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Sample records for stand-alone interbody fusion

  1. Stand-Alone Lateral Interbody Fusion for the Treatment of Low-Grade Degenerative Spondylolisthesis

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    Luis Marchi

    2012-01-01

    Full Text Available The purpose of this paper was to investigate the stand-alone lateral interbody fusion as a minimally invasive option for the treatment of low-grade degenerative spondylolisthesis with a minimum 24-month followup. Prospective nonrandomized observational single-center study. 52 consecutive patients (67.6±10 y/o; 73.1% female; 27.4±3.4 BMI with single-level grade I/II single-level degenerative spondylolisthesis without significant spine instability were included. Fusion procedures were performed as retroperitoneal lateral transpsoas interbody fusions without screw supplementation. The procedures were performed in average 73.2 minutes and with less than 50cc blood loss. VAS and Oswestry scores showed lasting improvements in clinical outcomes (60% and 54.5% change, resp.. The vertebral slippage was reduced in 90.4% of cases from mean values of 15.1% preoperatively to 7.4% at 6-week followup (P<0.001 and was maintained through 24 months (7.1%, P<0.001. Segmental lordosis (P<0.001 and disc height (P<0.001 were improved in postop evaluations. Cage subsidence occurred in 9/52 cases (17% and 7/52 cases (13% spine levels needed revision surgery. At the 24-month evaluation, solid fusion was observed in 86.5% of the levels treated. The minimally invasive lateral approach has been shown to be a safe and reproducible technique to treat low-grade degenerative spondylolisthesis.

  2. Maintenance of Segmental Lordosis and Disk Height in Stand-alone and Instrumented Extreme Lateral Interbody Fusion (XLIF).

    Science.gov (United States)

    Malham, Gregory M; Ellis, Ngaire J; Parker, Rhiannon M; Blecher, Carl M; White, Rohan; Goss, Ben; Seex, Kevin A

    2017-03-01

    A prospective single-surgeon nonrandomized clinical study. To evaluate the radiographic and clinical outcomes, by fixation type, in extreme lateral interbody fusion (XLIF) patients and provide an algorithm for determining patients suitable for stand-alone XLIF. XLIF may be supplemented with pedicle screw fixation, however, since stabilizing structures remain intact, it is suggested that stand-alone XLIF can be used for certain indications. This eliminates the associated morbidity, though subsidence rates may be elevated, potentially minimizing the clinical benefits. A fixation algorithm was developed after evaluation of patient outcomes from the surgeon's first 30 cases. This algorithm was used prospectively for 40 subsequent patients to determine the requirement for supplemental fixation. Preoperative, postoperative, and 12-month follow-up computed tomography scans were measured for segmental and global lumbar lordosis and posterior disk height. Clinical outcome measures included back and leg pain (visual analogue scale), Oswestry Disability Index (ODI), and SF-36 physical and mental component scores (PCS and MCS). Preoperatively to 12-month follow-up there were increases in segmental lordosis (7.9-9.4 degrees, P=0.0497), lumbar lordosis (48.8-55.2 degrees, P=0.0328), and disk height (3.7-5.5 mm, P=0.0018); there were also improvements in back (58.6%) and leg pain (60.0%), ODI (44.4%), PCS (56.7%), and MCS (16.1%) for stand-alone XLIF. For instrumented XLIF, segmental lordosis (7.6-10.5 degrees, P=0.0120) and disk height (3.5-5.6 mm, Plordosis decreased (51.1-45.8 degrees, P=0.2560). Back (49.8%) and leg pain (30.8%), ODI (32.3%), PCS (37.4%), and MCS (2.0%) were all improved. Subsidence occurred in 3 (7.5%) stand-alone patients. The XLIF treatment fixation algorithm provided a clinical pathway to select suitable patients for stand-alone XLIF. These patients achieved positive clinical outcomes, satisfactory fusion rates, with sustained correction of lordosis and

  3. Biomechanical comparison of a new stand-alone anterior lumbar interbody fusion cage with established fixation techniques – a three-dimensional finite element analysis

    Directory of Open Access Journals (Sweden)

    Hsieh Pang-Hsing

    2008-06-01

    Full Text Available Abstract Background Initial promise of a stand-alone interbody fusion cage to treat chronic back pain and restore disc height has not been realized. In some instances, a posterior spinal fixation has been used to enhance stability and increase fusion rate. In this manuscript, a new stand-alone cage is compared with conventional fixation methods based on the finite element analysis, with a focus on investigating cage-bone interface mechanics and stress distribution on the adjacent tissues. Methods Three trapezoid 8° interbody fusion cage models (dual paralleled cages, a single large cage, or a two-part cage consisting of a trapezoid box and threaded cylinder were created with or without pedicle screws fixation to investigate the relative importance of the screws on the spinal segmental response. The contact stress on the facet joint, slip displacement of the cage on the endplate, and rotational angle of the upper vertebra were measured under different loading conditions. Results Simulation results demonstrated less facet stress and slip displacement with the maximal contact on the cage-bone interface. A stand-alone two-part cage had good slip behavior under compression, flexion, extension, lateral bending and torsion, as compared with the other two interbody cages, even with the additional posterior fixation. However, the two-part cage had the lowest rotational angles under flexion and torsion, but had no differences under extension and lateral bending. Conclusion The biomechanical benefit of a stand-alone two-part fusion cage can be justified. This device provided the stability required for interbody fusion, which supports clinical trials of the cage as an alternative to circumferential fixations.

  4. [Biomechanicsl evaluation of a stand-alone interbody fusion cage based on porous TiO2/glass-ceramic on the human cervical spine].

    Science.gov (United States)

    Korinth, M C; Moersch, S; Ragoss, C; Schopphoff, E

    2003-12-01

    Recently, there has been a rapid increase in the use of cervical spine interbody fusion cages, differing in design and biomaterial used, in competition to autologous iliac bone graft and bone cement (PMMA). Limited biomechanical differences in primary stability, as well as advantages and disadvantages of each cage or material have been investigated in studies, using an in vitro human cervical spine model. 20 human cervical spine specimens were tested after fusion with either a cubical stand-alone interbody fusion cage manufactured from a new porous TiO2/glass composite (Ecopore) or PMMA after discectomy. Non-destructive biomechanical testing was performed, including flexion/extension and lateral bending using a spine testing apparatus. Three-dimensional segmental range of motion (ROM) was evaluated using an ultrasound measurement system. ROM increased more in flexion/extension and lateral bending after PMMA fusion (26.5%/36.1%), then after implantation of the Ecopore-cage (8.1%/7.8%). In this first biomechanical in vitro examination of a new porous ceramic bone replacement material a) the feasibility and reproducibility of biomechanical cadaveric cervical examination and its applicability was demonstrated, b) the stability of the ceramic cage as a stand alone interbody cage was confirmed in vitro, and c) basic information and knowledge for our intended biomechanical and histological in vivo testing, after implantation of Ecopore in cervical sheep spines, were obtained.

  5. Segmental kyphosis after cervical interbody fusion with stand-alone polyetheretherketone (PEEK) cages: a comparative study on 2 different PEEK cages.

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    Kim, Chi Heon; Chung, Chun Kee; Jahng, Tae-Ahn; Park, Sung Bae; Sohn, Seil; Lee, Sungjoon

    2015-02-01

    Retrospective comparative study. Two polyetheretherketone (PEEK) cages of different designs were compared in terms of the postoperative segmental kyphosis after anterior cervical discectomy and fusion. Segmental kyphosis occasionally occurs after the use of a stand-alone cage for anterior cervical discectomy and fusion. Although PEEK material seems to have less risk of segmental kyphosis compared with other materials, the occurrence of segmental kyphosis for PEEK cages has been reported to be from 0% to 29%. There have been a few reports that addressed the issue of PEEK cage design. A total of 41 consecutive patients who underwent single-level anterior discectomy and fusion with a stand-alone cage were included. Either a round tube-type (Solis; 18 patients, S-group) or a trapezoidal tube-type (MC+; 23 patients, M-group) cage was used. The contact area between the cage and the vertebral body is larger in MC+ than in Solis, and anchoring pins were present in the Solis cage. The effect of the cage type on the segmental angle (SA) (lordosis vs. kyphosis) at postoperative month 24 was analyzed. Preoperatively, segmental lordosis was present in 12/18 S-group and 16/23 M-group patients (P=0.84). The SA was more lordotic than the preoperative angle in both groups just after surgery, with no difference between groups (P=0.39). At 24 months, segmental lordosis was observed in 9/18 S-group and 20/23 M-group patients (P=0.01). The patients in M-group were 7.83 times more likely than patients in S-group (P=0.04; odds ratio, 7.83; 95% confidence interval, 1.09-56.28) not to develop segmental kyphosis. The design of the PEEK cage used may influence the SA, and this association needs to be considered when using stand-alone PEEK cages.

  6. [Application of a stand-alone interbody fusion cage based on a novel porous TiO2/glass composite. I. Implantation in the sheep cervical spine and radiological evaluation].

    Science.gov (United States)

    Korinth, M C; Hero, T; Mahnken, A H; Ragoss, C; Scherer, K

    2004-12-01

    Animals are becoming more and more common as in vitro and in vivo models for the human spine. Especially the sheep cervical spine is stated to be of good comparability and usefulness in the evaluation of in vivo radiological, biomechanical and histological behaviour of new bone replacement materials, implants and cages for cervical spine interbody fusion. In preceding biomechanical in vitro examination human cervical spine specimens were tested after fusion with either a cubical stand-alone interbody fusion cage manufactured from a new porous TiO/glass composite (Ecopore) or polymethyl-methacrylate (PMMA) after discectomy. First experience with the use of the new material and its influence on the primary stability after in vitro application were gained. After fusion of 10 sheep cervical spines in the levels C2/3 and C4/5 in each case with PMMA and with an Ecopore-cage, radiologic as well as computertomographic examinations were performed postoperatively and every 4 weeks during the following 2 and 4 months, respectively. Apart from establishing our animal model, we analysed the radiological changes and the degree of bony fusion of the operated segments during the course. In addition we performed measurements of the corresponding disc space heights (DSH) and intervertebral angles (IVA) for comparison among each other, during the course and with the initial values. Immediately after placement of both implants in the disc spaces the mean DSH and IVA increased (34.8% and 53.9%, respectively). During the following months DSH decreased to a greater extent in the Ecopore-segments than in the PMMA-segments, even to a value below the initial value (p>0.05). Similarly, the IVA decreased in both groups in the postoperative time lapse, but more distinct in the Ecopore-segments (pmodel of the sheep cervical spine. Distinct radiological changes regarding evident subsidence and detectable fusion of the segments, operated on with the new biomaterial, were seen. We demonstrated the

  7. [Clinical application of stand-alone MC+PEEK cage in the anterior cervical fusion].

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    Jiang, Bing; Cao, Yan-Qing; Pan, Hong; Zhu, Cheng-Run; Zhang, Xiao-Jun; Tao, Yue-Feng; Liu, Zhen

    2015-04-01

    To explore the effect of clinical application of stand-alone MC+PEEK cage in anterior cervical fusion. From January 2011 to January 2014,50 patients were treated with the MC+PEEK cage filled with autogenous cancellous illic-bone graft after anterior cervical discectomy. There were 22 patients with cervical spondylosis,26 patients with traumatic cervical disc herniation, 2 patients with cervical instability in these patients. There were 32 males and 18 females, aged from 30 to 79 years old with an average of 53.30 years old. There were 32 patients with single segment, 15 patients with double segments and 3 patients with three segments. Cervical AP and lateral and the flexion-extension X-rays were regularly taken in order to assess the cervical physiological curvature, the graft fusion and internal fixation related complications. Nerve function, clinical effect and bone fusion were respectively evaluated according to Japan Orthopedic Association (JOA), Otani grade and Suk method. All patients were followed up from 6 to 36 months with an average of 20 months. No correlated surgical complications were found and all patients obtained bony fusion with an average time of 4.30 months. JOA score had significantly improvement after surgery (P cervical fusion can obtain satisfactory clinical effect with less operation injury and reduce the complications. It is a better fusion method in anterior cervical fusion.

  8. Clinical and radiological outcome after anterior cervical discectomy and fusion with stand-alone empty polyetheretherketone (PEEK) cages.

    Science.gov (United States)

    Shiban, Ehab; Gapon, Karina; Wostrack, Maria; Meyer, Bernhard; Lehmberg, Jens

    2016-02-01

    To evaluate long-term results after one-, two-, and three-level anterior cervical discectomy and fusion (ACDF) with stand-alone empty polyetheretherketone (PEEK) cages. We performed a retrospective review of a consecutive patient cohort that underwent ACDF with stand-alone empty PEEK cages between 2007 and 2010 with a minimum follow-up of 12 months. Radiographic follow-up included static and flexion/extension radiographs. Changes in the operated segments were measured and compared to radiographs directly after surgery. Clinical outcome was evaluated by a physical examination, pain visual analog scale (VAS), and health-related quality of life (HRQL) using the EuroQOL questionnaire (EQ-5D). Analysis of associations between fusion, subsidence, cervical alignment, and clinical outcome parameters were performed. Of 407 consecutive cases, 318 met all inclusion criteria. Follow-up data were obtained from 265 (83 %) cases. The mean age at presentation was 55 years and 139 patients were male (52 %). In the sample, 127, 125, and 13 patients had one-, two-, and three-level surgeries, respectively; 132 (49 %) presented with spondylotic cervical myelopathy and 133 (50 %) with cervical radiculopathy. Fusion was achieved in 85, 95, and 94 % of segments in one-, two-, and three-level surgeries, respectively. Non-fusion was associated with higher VAS pain levels. Radiographic adjacent segment disease (ASD) was observed in 20, 29, and 15 % in one-, two-, and three-level surgeries, respectively. ASD was associated with lower HRQL. Subsidence was observed in 25, 27, and 15 % of segments in one-, two-, and three-level surgeries, respectively. However, this had no influence on clinical outcome. Follow-up operations for symptomatic adjacent disc disease and implant failure at index level were needed in 16 (6 %) and four (1.5 %) cases, respectively. Younger age was associated with better clinical outcome. Multilevel surgery favored better myelopathy outcomes and fusion reduced overall

  9. Stand-alone XLIF

    DEFF Research Database (Denmark)

    Hansen, E. J.; Simony, A.; Hummel, Stefan

    2015-01-01

    and clinical/radiological results in 22 patients treated with XLIF procedure for DS or degenerative disc disease (DDD). Material and methods: 22 consecutive patients with DS underwent surgery with the XLIF stand-alone procedure, with follow-up of 24 months. Clinical outcome scores were collected. Complications......Introduction: Adult thoracolumbar degeneration is an increasing challenge in the aging population. With age the progressive degeneration of the discs leads to an asymmetric collapse and a thoracolumbar coronal plane deformity, a degenerative scoliosis (DS). Aim: To evaluate the complication rate......-year follow-up, with a 31.8% revision rate. Due to the high revision rate we recommend supplementary posterior instrumentation, to achieve a higher fusion rate. When considering XLIF-stand-alone procedure for DS or DDD without supplemental posterior instrumentation, only single-level disease should...

  10. The da Vinci robotic surgical assisted anterior lumbar interbody fusion: technical development and case report.

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    Beutler, William J; Peppelman, Walter C; DiMarco, Luciano A

    2013-02-15

    Technique development to use the da Vince Robotic Surgical System for anterior lumbar interbody fusion at L5-S1 is detailed. A case report is also presented. To evaluate and develop the da Vinci robotic assisted laparoscopic anterior lumbar stand-alone interbody fusion procedure. Anterior lumbar interbody fusion is a common procedure associated with potential morbidity related to the surgical approach. The da Vinci robot provides intra-abdominal dissection and visualization advantages compared with the traditional open and laparoscopic approach. The surgical techniques for approach to the anterior lumbar spine using the da Vinci robot were developed and modified progressively beginning with operative models followed by placement of an interbody fusion cage in the living porcine model. Development continued to progress with placement of fusion cage in a human cadaver, completed first in the laboratory setting and then in the operating room. Finally, the first patient with fusion completed using the da Vinci robot-assisted approach is presented. The anterior transperitoneal approach to the lumbar spine is accomplished with enhanced visualization and dissection capability, with maintenance of pneumoperitoneum using the da Vinci robot. Blood loss is minimal. The visualization inside the disc space and surrounding structures was considered better than current open and laparoscopic techniques. The da Vinci robot Surgical System technique continues to develop and is now described for the transperitoneal approach to the anterior lumbar spine. 4.

  11. Anterior interbody fusion for cervical osteomyelitis

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    Bartal, A. D.; Schiffer, J.; Heilbronn, Y. D.; Yahel, M.

    1972-01-01

    Interbody fusion for stabilization of the cervical spine after osteomyelitic destruction of the body of C5 vertebra is reported in a patient with quadriplegia and sphincter disturbances secondary to an epidural abscess. The successful union of the bone graft along with complete neurological recovery after anterior decompression and evacuation of the epidural mass seem to justify the procedure. Images PMID:4554587

  12. [Mechanical studies of lumbar interbody fusion implants].

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    Bader, R J; Steinhauser, E; Rechl, H; Mittelmeier, W; Bertagnoli, R; Gradinger, R

    2002-05-01

    In addition to autogenous or allogeneic bone grafts, fusion cages composed of metal or plastic are being used increasingly as spacers for interbody fusion of spinal segments. The goal of this study was the mechanical testing of carbon fiber reinforced plastic (CFRP) fusion cages used for anterior lumbar interbody fusion. With a special testing device according to American Society for Testing and Materials (ASTM) standards, the mechanical properties of the implants were determined under four different loading conditions. The implants (UNION cages, Medtronic Sofamor Danek) provide sufficient axial compression, shear, and torsional strength of the implant body. Ultimate axial compression load of the fins is less than the physiological compression loads at the lumbar spine. Therefore by means of an appropriate surgical technique parallel grooves have to be reamed into the endplates of the vertebral bodies according to the fin geometry. Thereby axial compression forces affect the implants body and the fins are protected from damaging loading. Using a supplementary anterior or posterior instrumentation, in vivo failure of the fins as a result of physiological shear and torsional spinal loads is unlikely. Due to specific complications related to autogenous or allogeneic bone grafts, fusion cages made of metal or carbon fiber reinforced plastic are an important alternative implant in interbody fusion.

  13. A stand alone computer system to aid the development of mirror fusion test facility RF heating systems

    International Nuclear Information System (INIS)

    Thomas, R.A.

    1983-01-01

    The Mirror Fusion Test Facility (MFTF-B) control system architecture requires the Supervisory Control and Diagnostic System (SCDS) to communicate with a LSI-11 Local Control Computer (LCC) that in turn communicates via a fiber optic link to CAMAC based control hardware located near the machine. In many cases, the control hardware is very complex and requires a sizable development effort prior to being integrated into the overall MFTF-B system. One such effort was the development of the Electron Cyclotron Resonance Heating (ECRH) system. It became clear that a stand alone computer system was needed to simulate the functions of SCDS. This paper describes the hardware and software necessary to implement the SCDS Simulation Computer (SSC). It consists of a Digital Equipment Corporation (DEC) LSI-11 computer and a Winchester/Floppy disk operating under the DEC RT-11 operating system. All application software for MFTF-B is programmed in PASCAL, which allowed us to adapt procedures originally written for SCDS to the SSC. This nearly identical software interface means that software written during the equipment development will be useful to the SCDS programmers in the integration phase

  14. Mini-open transforaminal lumbar interbody fusion.

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    Tangviriyapaiboon, Teera

    2008-09-01

    To demonstrate the surgical technique and advantages of the mini-open transforaminal approach for lumbar interbody fusion (TLIF) combined with transpedicular screw fixation. Clinical and radiographic results were assessed to determine the clinical outcomes in twelve consecutive patients selected for minimally invasive access (mini-open technique) for TLIF in Prasat Neurological Institute. A retrospective analysis was performed on 12 patients (age range, 38-74 yr; mean, 54. 8 yr) who underwent mini-open transforaminal approach for lumbar interbody fusion (TLIF) combined with transpedicular screw fixation between September 2006 and June 2008. The titanium pedicle screws were introduced bilaterally through the 3.5 cm length, skin incisions with Spine Classics MLD- system retractor, autologous bone graft were inserted to perform TLIF in all patients. Eight patients were augmented anterior column support with titanium interbody cage, unilateral cage insertion in four patients and the others were inserted bilaterally interbody cages. Six patients presented with low back pain and associated radiculopathy, and six presented with low back pain only. Transforaminal lumbar interbody fusion was performed at L3-L4 in two patients, L4-L5 in four patients, L5-S1 in five patients, and two levels fusion in one patient. All patients were able to ambulate after spinal fusion. The patients were able to walk within 1.4 days (range 1-2 days). The hospital stay averaged 4.4 days (range 3-7 days). Periodic follow-up took place 1 to 21 months after surgery (mean, 7.4 months). The radiological fusion was archived in all nine patients who were operated on more than two months age. The other three patients who had been follow-up less than two months were probably fusion on the 1-month followed-up radiological examination. The use of mini-open technique for pedicle screw instrumentation with spinal fusion procedure provides excellent clinical results and may be an operation of choice for

  15. Complications in posterior lumbar interbody fusion

    OpenAIRE

    Kreuzer, Rolf-Peter

    2010-01-01

    From 1993 to 2000, 220 consecutive patients with unstable degenerative spondylolisthesis were studied after posterior lumbar interbody fusion (PLIF) using different types of grafts and pedicle screw systems. In a retrospective review the author detail the associated complications and their correlation with perioperative factors. The causes, strategies for their avoidance, and the clinical course of these complications are also disscused. The study group was composed of 136 women and 84 men...

  16. Lateral Interbody Fusion for Treatment of Discogenic Low Back Pain: Minimally Invasive Surgical Techniques

    Directory of Open Access Journals (Sweden)

    Luis Marchi

    2012-01-01

    Full Text Available Low back pain is one of the most common ailments in the general population, which tends to increase in severity along with aging. While few patients have severe enough symptoms or underlying pathology to warrant surgical intervention, in those select cases treatment choices remain controversial and reimbursement is a substancial barrier to surgery. The object of this study was to examine outcomes of discogenic back pain without radiculopathy following minimally-invasive lateral interbody fusion. Twenty-two patients were treated at either one or two levels (28 total between L2 and 5. Discectomy and interbody fusion were performed using a minimallyinvasive retroperitoneal lateral transpsoas approach. Clinical and radiographic parameters were analyzed at standard pre- and postoperative intervals up to 24 months. Mean surgical duration was 72.1 minutes. Three patients underwent supplemental percutaneous pedicle screw instrumentation. Four (14.3% stand-alone levels experienced cage subsidence. Pain (VAS and disability (ODI improved markedly postoperatively and were maintained through 24 months. Segmental lordosis increased significantly and fusion was achieved in 93% of levels. In this series, isolated axial low back pain arising from degenerative disc disease was treated with minimally-invasive lateral interbody fusion in significant radiographic and clinical improvements, which were maintained through 24 months.

  17. [Axial lumbar interbody fusion: prospective monocentric study].

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    Stulík, J; Adámek, S; Barna, M; Kaspříková, N; Polanecký, O; Kryl, J

    2014-01-01

    The aim of this prospective study was to evaluate clinical and radiographic results in the patients who underwent L5-S1 fixation using the technique of percutaneous lumbar interbody fusion (AxiaLIF). The study comprised 23 patients, 11 women and 12 men, who ranged from age of 21 to 63 years, with an average of 48.2 years. In all patients surgical posterior stabilisation involving the L5-S1 segment had previously been done. The initial indications for surgery were L5-S1 spondylolisthesis in 20 and L5-S1 spondylosis and stenosis in three patients. The AxiaLIF technique for L5-S1 fixation was indicated in overweight patients and in those after repeated abdominal or retroperitoneal surgery. A suitable position and shape of the sacrum or lumbosacral junction was another criterion. The patients were evaluated between 26 and 56 months (average, 40.4 months) after primary surgery and, on the basis of CT and radiographic findings, bone union and lumbosacral junction stability were assessed. The clinical outcome was investigated using the ODI and VAS systems and the results were statistically analysed by the Wilcoxon test for paired samples with statistical significance set at a level of 0.05. The average VAS value was 6.6 before surgery and, after surgery, 5.2 at three months, 4.2 at six months, 3.1 at one year, 2.9 at two years and 2.1 at three years (n=18). At two post-operative years, improvement in the VAS value by 56.1% was recorded. The average pre-operative ODI value was 25.1; the post-operative values were 17.0 at six months, 12.3 at one year, 10.6 at two years and 8.2 at three years (n=18). At two years after surgery the ODI value improved by 57.8%. To the question concerning their willingness to undergo, with acquired experience, surgery for the same diagnosis, 21 patients (91.3%) gave an affirmative answer. Neither screw breakage nor neurovascular damage or rectal injury was found. CT scans showed complete interbody bone fusion in 22 of the 23 patients (95

  18. Single anterior cervical discectomy and fusion (ACDF) using self- locking stand-alone polyetheretherketone (PEEK) cage: evaluation of pain and health-related quality of life.

    Science.gov (United States)

    Kapetanakis, Stylianos; Thomaidis, Tryfon; Charitoudis, George; Pavlidis, Pavlos; Theodosiadis, Panagiotis; Gkasdaris, Grigorios

    2017-09-01

    Anterior cervical discectomy and fusion (ACDF) constitutes the conventional treatment of cervical disc herniation due to degenerative disc disease (DDD). ACDF with plating presents a variety of complications postoperatively and stand-alone cages are thought to be a promising alternative. The aim of this study was firstly, to analyze prospectively collected data from a sample of patients treated with single ACDF using C-Plus self-locking stand-alone PEEK cage system, without the use of plates or screws, in order to evaluate pain levels of patients, utilizing Neck and Arm Pain scale as an expression of visual analogue scale (VAS). Secondly, we aimed to evaluate health-related quality of life, via the short-form 36 (SF-36) and Neck Disability Index (NDI). Thirty-six patients (19 male and 17 female) with mean age 49.6±7 years old who underwent successful single ACDF using self-locking stand-alone PEEK cage for symptomatic cervical DDD were selected for the study. Neck and Arm pain, as well as SF-36 and NDI were estimated preoperatively and 1, 3, 6, and 12 months postoperatively. Patients underwent preoperative and postoperative clinical, neurological and radiological evaluation. The clinical and radiological outcomes were satisfactory after a minimum 1-year follow-up. All results were statistically important (P<0.05), excluding improvement in NDI measured between 6 and 12 months. SF-36, Neck Pain, as well as Arm Pain featured gradual and constant improvement during follow-up, with best scores presenting at 12 months after surgery, while NDI reached its best at 6 months postoperatively. Generally, all scores showed improvement postoperatively during the different phases of the follow-up. Subsequently, ACDF using C-Plus cervical cage constitutes an effective method for cervical disc herniation treatment, in terms of postoperative improvement on pain levels and health-related quality of life and a safe alternative to the conventional method of treatment for cervical DDD.

  19. Single or double-level anterior interbody fusion techniques for cervical degenerative disc disease

    NARCIS (Netherlands)

    Jacobs, Wilco; Willems, Paul C.; van Limbeek, Jacques; Bartels, Ronald; Pavlov, Paul; Anderson, Patricia G.; Oner, Cumhur

    2011-01-01

    Background The number of surgical techniques for decompression and solid interbody fusion as treatment for cervical spondylosis has increased rapidly, but the rationale for the choice between different techniques remains unclear. Objectives To determine which technique of anterior interbody fusion

  20. Risk factors for subsidence in anterior cervical fusion with stand-alone polyetheretherketone (PEEK) cages: a review of 82 cases and 182 levels.

    Science.gov (United States)

    Kao, Ting-Hsien; Wu, Chen-Hao; Chou, Yu-Ching; Chen, Hsien-Te; Chen, Wen-Hsien; Tsou, Hsi-Kai

    2014-10-01

    To determine risk factors for subsidence in patients treated with anterior cervical discectomy and fusion (ACDF) and stand-alone polyetheretherketone (PEEK) cages. Records of patients with degenerative spondylosis or traumatic disc herniation resulting in radiculopathy or myelopathy between C2 and C7 who underwent ACDF with stand-alone PEEK cages were retrospectively reviewed. Cages were filled with autogenous cancellous bone harvested from iliac crest or hydroxyapatite. Subsidence was defined as a decrease of 3 mm or more of anterior or posterior disc height from that measured on the postoperative radiograph. Eighty-two patients (32 males, 50 females; 182 treatment levels) were included in the analysis. Most patients had 1-2 treatment levels (62.2 %), and 37.8 % had 3-4 treatment levels. Treatment levels were from C2-7. Of the 82 patients, cage subsidence occurred in 31 patients, and at 39 treatment levels. Multivariable analysis showed that subsidence was more likely to occur in patients with more than two treatment levels, and more likely to occur at treatment levels C5-7 than at levels C2-5. Subsidence was not associated with postoperative alignment change but associated with more disc height change (relatively oversized cage). Subsidence is associated with a greater number of treatment levels, treatment at C5-7 and relatively oversized cage use.

  1. Comparison of interbody fusion approaches for disabling low back pain.

    Science.gov (United States)

    Hacker, R J

    1997-03-15

    This is a study comparing two groups of patients surgically treated for disabling low back pain. One group was treated with lumbar anteroposterior fusion (360 degrees fusion), the other with posterior lumbar interbody fusion and an interbody fixation device. To determine which approach provided the best and most cost-effective outcome using similar patient selection criteria. Others have shown that certain patients with disabling low back pain benefit from lumbar fusion. Although rarely reported, the costs of different surgical treatments appear to vary significantly, whereas the patient outcome may vary little. Since 1991, 75 patients have been treated Starting in 1993, posterior lumbar interbody fusion BAK was offered to patients as an alternative to 360 degrees fusion. The treating surgeon reviewed the cases. The interbody fixation device used (BAK; Spine-Tech, Inc., Minneapolis, MN) was part of a Food and Drug Administration study. Patient selection criteria included examination, response to conservative therapy, imaging, psychological profile, and discography. North American Spine Society outcome questionnaires, BAK investigation data radiographs, chart entries, billing records and patient interviews were the basis for assessment. Age, sex compensable injury history and history of previous surgery were similar. Operative time; blood loss, hospitalization time, and total costs were significantly different. There was a quicker return to work and closure of workers compensation claims for the posterior lumbar interbody fusion-BAK group. Patient satisfaction was comparable at last follow-up. Posterior lumbar interbody fusion-BAK achieves equal patient satisfaction but fiscally surpasses the 360 degrees fusion approach. Today's environment of regulated medical practice requires the surgeon to consider cost effectiveness when performing fusion for low back pain.

  2. Anterior lumbar interbody fusion versus transforaminal lumbar interbody fusion--systematic review and meta-analysis.

    Science.gov (United States)

    Phan, Kevin; Thayaparan, Ganesha K; Mobbs, Ralph J

    2015-01-01

    To assess the clinical and radiographic outcomes and complications of anterior lumbar interbody fusion (ALIF) versus transforaminal lumbar interbody fusion (TLIF). A systematic literature search was conducted from six electronic databases. The relative risk and weighted mean difference (WMD) were used as statistical summary effect sizes. Fusion rates (88.6% vs. 91.9%, P = 0.23) and clinical outcomes were comparable between ALIF and TLIF. ALIF was associated with restoration of disk height (WMD, 2.71 mm, P = 0.01), segmental lordosis (WMD, 2.35, P = 0.03), and whole lumbar lordosis (WMD, 6.33, P = 0.03). ALIF was also associated with longer hospitalization (WMD, 1.8 days, P = 0.01), lower dural injury (0.4% vs. 3.8%, P = 0.05) but higher blood vessel injury (2.6% vs. 0%, P = 0.04). ALIF and TLIF appear to have similar success and clinical outcomes, with different complication profiles. ALIF may be associated with superior restoration of disk height and lordosis, but requires further validation in future studies.

  3. ANALYSIS OF INTERBODY VERSUS POSTEROLATERAL FUSION FOR LUMBAR SPONDYLOSIS

    Directory of Open Access Journals (Sweden)

    Rodrigo Góes Medéa de Mendonça

    2015-12-01

    Full Text Available Objective : To evaluate and compare radiographic and clinical evaluation of patients undergoing interbody fusion versus posterolateral fusion of the lumbar spine. Methods : Retrospective study of patients diagnosed with lumbar spondylosis that were surgically treated in the period from 2012 to 2014. The results were observed by clinical evaluation by the Visual Analogue Scale (VAS for low back and leg pain. We evaluated functional results and quality of life through the application of the Oswestry Disability Index (ODI and the Short Form-36 (SF-36 questionnaires, respectively. The pre and postoperative condition were compared in Group 1 (interbody fusion and Group 2 (posterolateral fusion, in addition to evaluation of fusion by means of post-operative radiograph. Results : A total of 30 patients of 36 were eligible, 12 in Group 1 and 18 in Group 2. The mean follow-up was 10.1 months. Statistical analysis showed similar scores for back and leg pain VAS, SF-36 function scores and Oswestry between groups with interbody and posterolateral fusion, and compared within these groups regarding the pre- and postoperative condition, and found no statistical significance. The successful fusion was similar in both groups, with 11 of 12 patients in Group 1 showing bone fusion and 17 of 18 in Group 2 showing arthrodesis. Conclusion : No clinical or radiographic differences between patients who underwent posterolateral or interbody fusion were observed. Both methods showed improvement in functional outcome and pain reduction.

  4. Biomechanics of an Expandable Lumbar Interbody Fusion Cage Deployed Through Transforaminal Approach

    Science.gov (United States)

    Mica, Michael Conti; Voronov, Leonard I.; Carandang, Gerard; Havey, Robert M.; Wojewnik, Bartosz

    2017-01-01

    Introduction A novel expandable lumbar interbody fusion cage has been developed which allows for a broad endplate footprint similar to an anterior lumbar interbody fusion (ALIF); however, it is deployed from a minimally invasive transforaminal unilateral approach. The perceived benefit is a stable circumferential fusion from a single approach that maintains the anterior tension band of the anterior longitudinal ligament. The purpose of this biomechanics laboratory study was to evaluate the biomechanical stability of an expandable lumbar interbody cage inserted using a transforaminal approach and deployed in situ compared to a traditional lumbar interbody cage inserted using an anterior approach (control device). Methods Twelve cadaveric spine specimens (L1-L5) were tested intact and after implantation of both the control and experimental devices in two (L2-L3 and L3-L4) segments of each specimen; the assignments of the control and experimental devices to these segments were alternated. Effect of supplemental pedicle screw-rod stabilization was also assessed. Moments were applied to the specimens in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). The effect of physiologic preload on construct stability was evaluated in FE. Segmental motions were measured using an optoelectronic motion measurement system. Results The deployable expendable TLIF cage and control devices significantly reduced FE motion with and without compressive preload when compared to the intact condition (p0.05). Adding bilateral pedicle screws resulted in further reduction of ROM for all loading modes compared to intact condition, with no statistical difference between the two constructs (p>0.05). Conclusions The ability of the deployable expendable interbody cage in reducing segmental motions was equivalent to the control cage when used as a stand-alone construct and also when supplemented with bilateral pedicle screw-rod instrumentation. The larger footprint of the fully

  5. Posterior lumbar interbody fusion with stand-alone Trabecular Metal cages for repeatedly recurrent lumbar disc herniation and back pain

    NARCIS (Netherlands)

    Lequin, Michiel B.; Verbaan, Dagmar; Bouma, Gerrit J.

    2014-01-01

    Patients with recurrent sciatica due to repeated reherniation of the intervertebral disc carry a poor prognosis for recovery and create a large burden on society. There is no consensus about the best treatment for this patient group. The goal of this study was to evaluate the 12-month results of the

  6. CHANGES IN RADIOGRAPHIC PARAMETERS AFTER MINIMALLY INVASIVE LUMBAR INTERBODY FUSION

    Directory of Open Access Journals (Sweden)

    Emiliano Vialle

    2015-12-01

    Full Text Available Objective : This study aims to evaluate changes in lumbosacral parameters after minimally invasive lumbar interbody fusion. The secondary aim was to evaluate whether interbody cage shape (crescent shaped or rectangular would influence the results. Method : Retrospective analysis of 70 patients who underwent one or two level lumbar interbody fusion through a minimally invasive posterolateral approach. This included midline preservation and unilateral facetectomy. Pre- and postoperative (three to six months postoperative radiographs were used for measuring lumbar lordosis (LL, segmental lordosis (SL at the level of interbody fusion, and sacral slope (SS. Further analyses divided the patients into Roussouly lumbar subgroups. Results : LL was significantly reduced after surgery (59o:39o, p=0.001 as well as the SS (33.8o:31.2o, p=0.05. SL did not change significantly (11.4:11.06, p=0.85. There were no significant differences when comparing patients who received crescent shaped cage (n=27 and rectangular cage (n=43. Hypolordotic patients (Roussouly types 1 and 2 had radiographic improvement in comparison to normolordotic and hyperlordotic groups (types 3 and 4. Conclusion : Minimally invasive lumbar interbody fusion caused reduction in lumbosacral parameters. Cage shape had no influence on the results.

  7. [Anterior lumbar interbody fusion. Indications, technique, advantages and disadvantages].

    Science.gov (United States)

    Richter, M; Weidenfeld, M; Uckmann, F P

    2015-02-01

    Anterior lumbar interbody fusion (ALIF) for lumbar interbody fusion from L2 to the sacrum has been an established technique for decades. The advantages and disadvantages of ALIF compared to posterior interbody fusion techniques are discussed. The operative technique is described in detail. Complications and avoidance strategies are discussed. This article is based on a selective literature search using PubMed and the experience of the authors in this medical field. The advantages of ALIF compared to posterior fusion techniques are the free approach to the anterior disc space without opening of the spinal canal or the neural foramina. This gives the possibility of an extensive anterior release and placement of the largest possible cages without the risk of neural structure damage. The disadvantages of ALIF are the additional anterior approach and the related complications. The most frequent complication is due to damage of vessels. The rate of complications is significantly increased in revision surgery. The ALIF technique meaningfully expands the repertoire of the spinal surgeon especially for the treatment of non-union after interbody fusion, in patients with epidural scar tissue at the index level and spinal infections. Advantages and disadvantages should be considered when evaluating the indications for ALIF.

  8. Lumbar interbody fusion: techniques, indications and comparison of interbody fusion options including PLIF, TLIF, MI-TLIF, OLIF/ATP, LLIF and ALIF

    Science.gov (United States)

    Phan, Kevin; Malham, Greg; Seex, Kevin; Rao, Prashanth J.

    2015-01-01

    Degenerative disc and facet joint disease of the lumbar spine is common in the ageing population, and is one of the most frequent causes of disability. Lumbar spondylosis may result in mechanical back pain, radicular and claudicant symptoms, reduced mobility and poor quality of life. Surgical interbody fusion of degenerative levels is an effective treatment option to stabilize the painful motion segment, and may provide indirect decompression of the neural elements, restore lordosis and correct deformity. The surgical options for interbody fusion of the lumbar spine include: posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), minimally invasive transforaminal lumbar interbody fusion (MI-TLIF), oblique lumbar interbody fusion/anterior to psoas (OLIF/ATP), lateral lumbar interbody fusion (LLIF) and anterior lumbar interbody fusion (ALIF). The indications may include: discogenic/facetogenic low back pain, neurogenic claudication, radiculopathy due to foraminal stenosis, lumbar degenerative spinal deformity including symptomatic spondylolisthesis and degenerative scoliosis. In general, traditional posterior approaches are frequently used with acceptable fusion rates and low complication rates, however they are limited by thecal sac and nerve root retraction, along with iatrogenic injury to the paraspinal musculature and disruption of the posterior tension band. Minimally invasive (MIS) posterior approaches have evolved in an attempt to reduce approach related complications. Anterior approaches avoid the spinal canal, cauda equina and nerve roots, however have issues with approach related abdominal and vascular complications. In addition, lateral and OLIF techniques have potential risks to the lumbar plexus and psoas muscle. The present study aims firstly to comprehensively review the available literature and evidence for different lumbar interbody fusion (LIF) techniques. Secondly, we propose a set of recommendations and guidelines

  9. Solar Charged Stand Alone Inverter

    OpenAIRE

    M.Vasugi; Prof R.Jayaraman

    2014-01-01

    This paper deals with solar powered stand alone inverter which converts the variable dc output of a photovoltaic solar panel into ac that can be fed to loads. Stand alone inverters are used in systems where the inverter get its energy from batteries charged by photo voltaic arrays. A charge controller limits the rate at which electric current is added to or drawn from electric batteries. This charge discharge controller is needed to prevent the battery from being overcharged o...

  10. POSTERIOR LUMBAR INTERBODY FUSION AND INSTRUMENTED POSTEROLATERAL FUSION IN ADULT SPONDYLOLISTHESIS: ASSESSMENT AND CLINICAL OUTCOME

    Directory of Open Access Journals (Sweden)

    Rajarajan

    2015-11-01

    Full Text Available OBJECTIVE: Aim of this study is to assess and compare the outcomes of posterior lumbar interbody fusion (PLIF and posterolateral fusion (PLF in adult isthmic spondylosthesis. BACKGROUND: Posterolateral fusion has been considered the best method and widely been used for surgical treatment of adult spondylolisthesis.Superior results have subsequently been reported with interbody fusion with cages and posterior instrumentation MATERIALS AND METHODS: Thirty six patients with isthmic spondylolisthesis were operated. One group (20 patients had decompression and posterolateral fusion (PLF with a pedicle screw system; other group (16 patients was treated by decompression, posterior lumbar interbody fusion (PLIF and a Pedicle screw system. In both groups adequate decompression was done RESULTS: Seventy seven percent of the patients had a good result with (PLIF and 68 percent with posterolateral fusion (PLF. However there was no statistical difference in cases with low grade slipping, whereas the difference was significant for cases with high grade slipping. Fusion rate was 93% with (PLIF and 68% with (PLF, but without any significant incidence in the functional outcome. 78% has relief of sciatica and neurogenic claudication. CONCLUSION: Based on these findings we found that for high grade spondylolisthesis which requires reduction or if the disc space is still high posterior lumbar inter body fusion is preferable. For low grade spondylolisthesis or if the disc space is narrow posterolateral fusion is preferable. A successful result of fusion operation depends on adequate decompression which relieves radicular symptoms.

  11. Anterior lumbar fusion with titanium threaded and mesh interbody cages.

    Science.gov (United States)

    Rauzzino, M J; Shaffrey, C I; Nockels, R P; Wiggins, G C; Rock, J; Wagner, J

    1999-12-15

    The authors report their experience with 42 patients in whom anterior lumbar fusion was performed using titanium cages as a versatile adjunct to treat a wide variety of spinal deformity and pathological conditions. These conditions included congenital, degenerative, iatrogenic, infectious, traumatic, and malignant disorders of the thoracolumbar spine. Fusion rates and complications are compared with data previously reported in the literature. Between July 1996 and July 1999 the senior authors (C.I.S., R.P.N., and M.J.R.) treated 42 patients by means of a transabdominal extraperitoneal (13 cases) or an anterolateral extraperitoneal approach (29 cases), 51 vertebral levels were fused using titanium cages packed with autologous bone. All vertebrectomies (27 cases) were reconstructed using a Miami Moss titanium mesh cage and Kaneda instrumentation. Interbody fusion (15 cases) was performed with either the BAK titanium threaded interbody cage (in 13 patients) or a Miami Moss titanium mesh cage (in two patients). The average follow-up period was 14.3 months. Seventeen patients had sustained a thoracolumbar burst fracture, 12 patients presented with degenerative spinal disorders, six with metastatic tumor, four with spinal deformity (one congenital and three iatrogenic), and three patients presented with spinal infections. In five patients anterior lumbar interbody fusion (ALIF) was supplemented with posterior segmental fixation at the time of the initial procedure. Of the 51 vertebral levels treated, solid arthrodesis was achieved in 49, a 96% fusion rate. One case of pseudarthrosis occurred in the group treated with BAK cages; the diagnosis was made based on the patient's continued mechanical back pain after undergoing L4-5 ALIF. The patient was treated with supplemental posterior fixation, and successful fusion occurred uneventfully with resolution of her back pain. In the group in which vertebrectomy was performed there was one case of fusion failure in a patient with

  12. The cost-effectiveness of interbody fusions versus posterolateral fusions in 137 patients with lumbar spondylolisthesis.

    Science.gov (United States)

    Bydon, Mohamad; Macki, Mohamed; Abt, Nicholas B; Witham, Timothy F; Wolinsky, Jean-Paul; Gokaslan, Ziya L; Bydon, Ali; Sciubba, Daniel M

    2015-03-01

    Reimbursements for interbody fusions have declined recently because of their questionable cost-effectiveness. A Markov model was adopted to compare the cost-effectiveness of posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (/TLIF) versus noninterbody fusion and posterolateral fusion (PLF) in patients with lumbar spondylolisthesis. Decision model analysis based on retrospective data from a single institutional series. One hundred thirty-seven patients underwent first-time instrumented lumbar fusions for degenerative or isthmic spondylolisthesis. Quality of life adjustments and expenditures were assigned to each short-term complication (durotomy, surgical site infection, and medical complication) and long-term outcome (bowel/bladder dysfunction and paraplegia, neurologic deficit, and chronic back pain). Patients were divided into a PLF cohort and a PLF plus PLIF/TLIF cohort. Anterior techniques and multilevel interbody fusions were excluded. Each short-term complication and long-term outcome was assigned a numerical quality-adjusted life-year (QALY), based on time trade-off values in the Beaver Dam Health Outcomes Study. The cost data for short-term complications were calculated from charges accrued by the institution's finance sector, and the cost data for long-term outcomes were estimated from the literature. The difference in cost of PLF plus PLIF/TLIF from the cost of PLF alone divided by the difference in QALY equals the cost-effectiveness ratio (CER). We do not report any study funding sources or any study-specific appraisal of potential conflict of interest-associated biases in this article. Of 137 first-time lumbar fusions for spondylolisthesis, 83 patients underwent PLF and 54 underwent PLIF/TLIF. The average time to reoperation was 3.5 years. The mean QALY over 3.5 years was 2.81 in the PLF cohort versus 2.66 in the PLIFo/TLIF cohort (p=.110). The mean 3.5-year costs of $54,827.05 after index interbody fusion were

  13. Analysis of Internet Information on Lateral Lumbar Interbody Fusion.

    Science.gov (United States)

    Belayneh, Rebekah; Mesfin, Addisu

    2016-07-01

    Lateral lumbar interbody fusion (LLIF) is a surgical technique that is being increasingly used. The authors' objective was to examine information on the Internet pertaining to the LLIF technique. An analysis was conducted of publicly accessible websites pertaining to LLIF. The following search engines were used: Google (www.google.com), Bing (www.bing.com), and Yahoo (www.yahoo.com). DuckDuckGo (www.duckduckgo.com) was an additional search engine used due to its emphasis on generating accurate and consistent results while protecting searchers' privacy and reducing advertisements. The top 35 websites providing information on LLIF from the 4 search engines were identified. A total of 140 websites were evaluated. Each web-site was categorized based on authorship (academic, private, medical industry, insurance company, other) and content of information. Using the search term lateral lumbar interbody fusion, 174,000 Google results, 112,000 Yahoo results, and 112,000 Bing results were obtained. DuckDuckGo does not display the number of results found for a search. From the top 140 websites collected from each website, 78 unique websites were identified. Websites were authored by a private medical group in 46.2% of the cases, an academic medical group in 26.9% of the cases, and the biomedical industry in 5.1% of the cases. Sixty-eight percent of websites reported indications, and 24.4% reported contraindications. Benefits of LLIF were reported by 69.2% of websites. Thirty-six percent of websites reported complications of LLIF. Overall, the quality of information regarding LLIF on the Internet is poor. Spine surgeons and spine societies can assist in improving the quality of the information on the Internet regarding LLIF. [Orthopedics. 2016; 39(4):e701-e707.]. Copyright 2016, SLACK Incorporated.

  14. The Stand-alone Heliostat

    International Nuclear Information System (INIS)

    Garcia Navajas, G. I.; Egea Gea, A.

    2000-01-01

    The first Autonomous Heliostat has been developed by CIEMAT at PSA facilities in Almeria. This heliostat is an innovative approach to reducing the civil engineering work costs in heliostat fields of central tower plants. Channels, cables and other electric elements have been eliminated in the new heliostat. Thus, one 70-nr, classical T glass/metal heliostat has been adapted to include all the new stand-alone concept components. A PV system is able to drive two sun-tracking DC motors between 5 and 24Vdc, 0 and 15A. The heliostat communicates with the control room 400-m away by using a radio-modem working at 9600 baud. An anemometer, a wind switcher, light and ambient temperature sensors have been installed on the heliostat for self-protection decision-making. A PV panel integrated into the heliostat reflecting surface, eliminates cabling and other elements required for a conventional power supply. Communication lines between master control and local control have been replaced by radio-modem. Testing has validated the technical feasibility of the prototype and quantified the real consumption and efficiencies of new elements. The extra costs produced.by the autonomous concepts are compared with the cost of civil work in conventional heliostat field. (Author) 8 refs

  15. Two-year outcomes of transforaminal lumbar interbody fusion.

    Science.gov (United States)

    Poh, Seng Yew; Yue, Wai Mun; Chen, Li-Tat John; Guo, Chang-Ming; Yeo, William; Tan, Seang-Beng

    2011-08-01

    To evaluate the outcomes, fusion rates, complications, and adjacent segment degeneration associated with transforaminal lumbar interbody fusion (TLIF). 32 men and 80 women aged 15 to 85 (mean, 57) years underwent 141 fusions (84 one-level, 27 2-level, and one 3-level) and were followed up for 24 to 76 (mean, 33) months. 92% of the patients had degenerative lumbar disease, 15 of whom had had previous lumbar surgery. Radiographic and clinical outcomes were assessed at 2 years. The short-form 36 (SF-36) health survey, visual analogue scale (VAS) for pain, and the modified North American Spine Society (NASS) Low Back Pain Outcome Instrument were used. Of the 141 levels fused, 110 (78%) were fused with remodelling and trabeculae (grade I), and 31 (22%) had intact grafts but were not fully incorporated (grade II). No patient had pseudoarthroses (grade III or IV). For one-level fusions, poorer radiological fusion grades correlated with higher VAS scores for pain (p<0.01). All components of the SF-36, the VAS scores for pain, and the NASS scores improved significantly after TLIF (p<0.01), except for general health in the SF-36 (p=0.59). Improvement from postoperative 6 months to 2 years was not significant, except for physical function (p<0.01) and role function (physical) [p=0.01] in the SF-36. Two years after TLIF, 50% of the patients reported returning to full function, whereas 72% were satisfied. 26 (23%) of the patients had adjacent segment degeneration, but only 4 of them were symptomatic. TLIF is a safe and effective treatment for degenerative lumbar diseases.

  16. Comparison of instrumented anterior interbody fusion with instrumented circumferential lumbar fusion.

    Science.gov (United States)

    Madan, S S; Boeree, N R

    2003-12-01

    Posterior lumbar interbody fusion (PLIF) restores disc height, the load bearing ability of anterior ligaments and muscles, root canal dimensions, and spinal balance. It immobilizes the painful degenerate spinal segment and decompresses the nerve roots. Anterior lumbar interbody fusion (ALIF) does the same, but could have complications of graft extrusion, compression and instability contributing to pseudarthrosis in the absence of instrumentation. The purpose of this study was to assess and compare the outcome of instrumented circumferential fusion through a posterior approach [PLIF and posterolateral fusion (PLF)] with instrumented ALIF using the Hartshill horseshoe cage, for comparable degrees of internal disc disruption and clinical disability. It was designed as a prospective study, comparing the outcome of two methods of instrumented interbody fusion for internal disc disruption. Between April 1994 and June 1998, the senior author (N.R.B.) performed 39 instrumented ALIF procedures and 35 instrumented circumferential fusion with PLIF procedures. The second author, an independent assessor (S.M.), performed the entire review. Preoperative radiographic assessment included plain radiographs, magnetic resonance imaging (MRI) and provocative discography in all the patients. The outcome in the two groups was compared in terms of radiological improvement and clinical improvement, measured on the basis of improvement of back pain and work capacity. Preoperatively, patients were asked to fill out a questionnaire giving their demographic details, maximum walking distance and current employment status in order to establish the comparability of the two groups. Patient assessment was with the Oswestry Disability Index, quality of life questionnaire (subjective), pain drawing, visual analogue scale, disability benefit, compensation status, and psychological profile. The results of the study showed a satisfactory outcome (scorelife questionnaire) score of 71.8% (28 patients) in

  17. Is the radiographic subsidence of stand-alone cages associated with adverse clinical outcomes after cervical spine fusion? An observational cohort study with 2-year follow-up outcome scoring.

    Science.gov (United States)

    Zajonz, Dirk; Franke, Anne-Catherine; von der Höh, Nicolas; Voelker, Anna; Moche, Michael; Gulow, Jens; Heyde, Christoph-Eckhard

    2014-01-01

    The stand-alone treatment of degenerative cervical spine pathologies is a proven method in clinical practice. However, its impact on subsidence, the resulting changes to the profile of the cervical spine and the possible influence of clinical results compared to treatment with additive plate osteosynthesis remain under discussion until present. This study was designed as a retrospective observational cohort study to test the hypothesis that radiographic subsidence of cervical cages is not associated with adverse clinical outcomes. 33 cervical segments were treated surgically by ACDF with stand-alone cage in 17 patients (11 female, 6 male), mean age 56 years (33-82 years), and re-examined after eight and twenty-six months (mean) by means of radiology and score assessment (Medical Outcomes Study Short Form (MOS-SF 36), Oswestry Neck Disability Index (ONDI), painDETECT questionnaire and the visual analogue scale (VAS)). Subsidence was observed in 50.5% of segments (18/33) and 70.6% of patients (12/17). 36.3% of cases of subsidence (12/33) were observed after eight months during mean time of follow-up 1. After 26 months during mean time of follow-up 2, full radiographic fusion was seen in 100%. MOS-SF 36, ONDI and VAS did not show any significant difference between cases with and without subsidence in the two-sample t-test. Only in one type of scoring (painDETECT questionnaire) did a statistically significant difference in t-Test emerge between the two groups (p = 0.03; α = 0.05). However, preoperative painDETECT score differ significantly between patients with subsidence (13.3 falling to 12.6) and patients without subsidence (7.8 dropped to 6.3). The radiological findings indicated 100% healing after stand-alone treatment with ACDF. Subsidence occurred in 50% of the segments treated. No impact on the clinical results was detected in the medium-term study period.

  18. Repeated adjacent-segment degeneration after posterior lumbar interbody fusion.

    Science.gov (United States)

    Okuda, Shinya; Oda, Takenori; Yamasaki, Ryoji; Maeno, Takafumi; Iwasaki, Motoki

    2014-05-01

    One of the most important sequelae affecting long-term results is adjacent-segment degeneration (ASD) after posterior lumbar interbody fusion (PLIF). Although several reports have described the incidence rate, there have been no reports of repeated ASD. The purpose of this report was to describe 1 case of repeated ASD after PLIF. A 62-year-old woman with L-4 degenerative spondylolisthesis underwent PLIF at L4-5. At the second operation, L3-4 PLIF was performed for L-3 degenerative spondylolisthesis 6 years after the primary operation. At the third operation, L2-3 PLIF was performed for L-2 degenerative spondylolisthesis 1.5 years after the primary operation. Vertebral collapse of L-1 was detected 1 year after the third operation, and the collapse had progressed. At the fourth operation, 3 years after the third operation, vertebral column resection of L-1 and replacement of titanium mesh cages with pedicle screw fixation between T-4 and L-5 was performed. Although the patient's symptoms resolved after each operation, the time between surgeries shortened. The sacral slope decreased gradually although each PLIF achieved local lordosis at the fused segment.

  19. Outcomes of extended transforaminal lumbar interbody fusion for lumbar spondylosis.

    Science.gov (United States)

    Talia, Adrian J; Wong, Michael L; Lau, Hui C; Kaye, Andrew H

    2015-11-01

    This study aims to assess the results of extended transforaminal lumbar interbody fusion (TLIF) for a two surgeon, single institution series. In total, extended TLIF with bilateral decompression was performed in 57 patients. Pain, American Spinal Injury Association scores, patient demographics, body mass index (BMI), perioperative indices and radiographic measurements were recorded and analysed. The surgeries were performed between February 2011 and January 2014 on 38 women and 19 men. The mean patient age was 62.86 years, and the mean BMI was 30.31 kg/m(2). In 49 patients, spondylolisthesis was the primary indication. The mean intraoperative time was 284.65 min, and this decreased as the series progressed. The median length of stay was 5 days (range: 2-9). The surgical complication rate was 19.3%. Two patients died from cardiopulmonary complications. Single level TLIF was performed in 78.9% of the cohort, with L4/5 the most commonly fused level. Significant pain reduction was achieved from a mean (± standard deviation) preoperative visual analogue scale (VAS) of 8.28 ± 1.39 to 1.50 ± 1.05 at 12 months postoperatively. No patients deteriorated neurologically. Spondylolisthesis was significantly corrected from a preoperative mean of 6.82 mm to 2.80 mm postoperatively. Although there is a learning curve associated with the procedure, extended TLIF with bilateral facet joint removal and decompression appeared to be a safe and effective alternative to other fusion techniques, and our results were comparable to other published case series. The stabilisation and correction of spinal deformity reduces pain, aids neurologic recovery and improves quality of life. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Evaluation of Anterior Vertebral Interbody Fusion Using Osteogenic Mesenchymal Stem Cells Transplanted in Collagen Sponge.

    Science.gov (United States)

    Yang, Wencheng; Dong, Youhai; Hong, Yang; Guang, Qian; Chen, Xujun

    2016-05-01

    The study used a rabbit model to achieve anterior vertebral interbody fusion using osteogenic mesenchymal stem cells (OMSCs) transplanted in collagen sponge. We investigated the effectiveness of graft material for anterior vertebral interbody fusion using a rabbit model by examining the OMSCs transplanted in collagen sponge. Anterior vertebral interbody fusion is commonly performed. Although autogenous bone graft remains the gold-standard fusion material, it requires a separate surgical procedure and is associated with significant short-term and long-term morbidity. Recently, mesenchymal stem cells from bone marrow have been studied in various fields, including posterolateral spinal fusion. Thus, we hypothesized that cultured OMSCs transplanted in porous collagen sponge could be used successfully even in anterior vertebral interbody fusion. Forty mature male White Zealand rabbits (weight, 3.5-4.5 kg) were randomly allocated to receive one of the following graft materials: porous collagen sponge plus cultured OMSCs (group I); porous collagen sponge alone (group II); autogenous bone graft (group III); and nothing (group IV). All animals underwent anterior vertebral interbody fusion at the L4/L5 level. The lumbar spine was harvested en bloc, and the new bone formation and spinal fusion was evaluated using radiographic analysis, microcomputed tomography, manual palpation test, and histologic examination at 8 and 12 weeks after surgery. New bone formation and bony fusion was evident as early as 8 weeks in groups I and III. And there was no statistically significant difference between 8 and 12 weeks. At both time points, by microcomputed tomography and histologic analysis, new bone formation was observed in both groups I and III, fibrous tissue was observed and there was no new bone in both groups II and IV; by manual palpation test, bony fusion was observed in 40% (4/10) of rabbits in group I, 70% (7/10) of rabbits in group III, and 0% (0/10) of rabbits in both groups

  1. Transforaminal lumbar interbody fusion vs. posterolateral instrumented fusion

    DEFF Research Database (Denmark)

    Christensen, A; Høy, K; Bünger, C

    2014-01-01

    difference in either cost or effects although a tendency for the TLIF regimen being more costly on bed days (a,not sign2,554) and production loss (a,not sign1,915) was observed. The probability that TLIF would be cost-effective did not exceed 30 % for any threshold of willingness to pay per quality......Long-lasting low back pain is an increasing problem, and for some patients surgery is the final option for improvement. Several techniques for spinal fusion are available and the optimal technique remains uncertain. The objective of this study was to assess the cost-effectiveness and cost...... Index and SF-6D questionnaires. Conventional cost-effectiveness methodology was employed to estimate net benefit and to illustrate cost-effectiveness acceptability curves. The statistical analysis was based on means and bootstrapped confidence intervals. Results showed no statistically significant...

  2. Basic Stand Alone Medicare Inpatient Claims PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Inpatient Public Use Files (PUF) named CMS 2008 BSA Inpatient Claims PUF with information from 2008 Medicare...

  3. Basic Stand Alone Carrier Line Items PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Carrier Line Items Public Use Files (PUF) with information from Medicare Carrier claims. The CMS BSA Carrier Line...

  4. Clinical study of bilateral decompression via vertebral lamina fenestration for lumbar interbody fusion in the treatment of lower lumbar instability

    OpenAIRE

    GUO, SHUGUANG; SUN, JUNYING; TANG, GENLIN

    2013-01-01

    The aim of this study was to observe the clinical effects of bilateral decompression via vertebral lamina fenestration for lumbar interbody fusion in the treatment of lower lumbar instability. The 48 patients comprised 27 males and 21 females, aged 47?72 years. Three cases had first and second degree lumbar spondylolisthesis and all received bilateral vertebral lamina fenestration for posterior lumbar interbody fusion (PLIF) using a threaded fusion cage (TFC), which maintains the three-column...

  5. Evaluation of a polyetheretherketone (PEEK) titanium composite interbody spacer in an ovine lumbar interbody fusion model: biomechanical, microcomputed tomographic, and histologic analyses.

    Science.gov (United States)

    McGilvray, Kirk C; Waldorff, Erik I; Easley, Jeremiah; Seim, Howard B; Zhang, Nianli; Linovitz, Raymond J; Ryaby, James T; Puttlitz, Christian M

    2017-12-01

    The most commonly used materials used for interbody cages are titanium metal and polymer polyetheretherketone (PEEK). Both of these materials have demonstrated good biocompatibility. A major disadvantage associated with solid titanium cages is their radiopacity, limiting the postoperative monitoring of spinal fusion via standard imaging modalities. However, PEEK is radiolucent, allowing for a temporal assessment of the fusion mass by clinicians. On the other hand, PEEK is hydrophobic, which can limit bony ingrowth. Although both PEEK and titanium have demonstrated clinical success in obtaining a solid spinal fusion, innovations are being developed to improve fusion rates and to create stronger constructs using hybrid additive manufacturing approaches by incorporating both materials into a single interbody device. The purpose of this study was to examine the interbody fusion characteristic of a PEEK Titanium Composite (PTC) cage for use in lumbar fusion. Thirty-four mature female sheep underwent two-level (L 2 -L 3 and L 4 -L 5 ) interbody fusion using either a PEEK or a PTC cage (one of each per animal). Animals were sacrificed at 0, 8, 12, and 18 weeks post surgery. Post sacrifice, each surgically treated functional spinal unit underwent non-destructive kinematic testing, microcomputed tomography scanning, and histomorphometric analyses. Relative to the standard PEEK cages, the PTC constructs demonstrated significant reductions in ranges of motion and a significant increase in stiffness. These biomechanical findings were reinforced by the presence of significantly more bone at the fusion site as well as ingrowth into the porous end plates. Overall, the results indicate that PTC interbody devices could potentially lead to a more robust intervertebral fusion relative to a standard PEEK device in a clinical setting. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  6. Comparison Between Posterior Lumbar Interbody Fusion and Transforaminal Lumbar Interbody Fusion for the Treatment of Lumbar Degenerative Diseases: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Lan, Tao; Hu, Shi-Yu; Zhang, Yuan-Tao; Zheng, Yu-Chen; Zhang, Rui; Shen, Zhe; Yang, Xin-Jian

    2018-04-01

    To compare the efficacy and safety in the management of lumbar diseases performed by either posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF). Interbody fusion is considered the "gold standard" in the treatment of lumbar degenerative diseases. Both PLIF and TLIF have been advocated, and it remains controversial as to the best operative technique. The electronic databases including Embase, PubMed, and Cochrane library were searched to identify relevant studies up to September 2017. The primary outcomes were fusion rate, complications, and clinical satisfaction. The secondary outcomes were length of hospitalization, operation time, blood loss, postoperative visual analog scale, Oswestry Disability Index, and Japanese Orthopaedic Association Score. Data analysis was conducted with RevMan 5.3 software. A total of 16 studies involving 1502 patients (805 patients in PLIF group and 697 in TLIF group) were included in the meta-analysis. The pooled analysis showed that there was no significant difference in terms of fusion rate (P > 0.05) and clinical satisfaction (P > 0.05) between the 2 groups. TLIF was superior to PLIF with significantly lower incidence of nerve root injury (P 0.05) and graft malposition (P > 0.05). PLIF required significant longer operation time (P degenerative lumbar diseases. However, TLIF was superior to PLIF with shorter operation time, less blood loss, and lower incidence of nerve root injury and dural tear. There is no significant difference between both groups regarding wound infection and graft malposition. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Stand alone photovoltaic systems: guarantee of results

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    This study aims to provide a guarantee of results for system performance for users of stand-alone photovoltaic (PV) systems, which have no back-up generator. The appropriate main performance criterion for PV systems is that a specified load is supplied with power either continuously or intermittently whenever the load requires power. A methodology to evaluate the power availability of stand-alone PV systems has been developed as part of the project, which encompasses power losses due to weather variations. The guarantee of results produced allows users to compare system designs from different manufacturers. (UK)

  8. Allograft Cellular Bone Matrix in Extreme Lateral Interbody Fusion: Preliminary Radiographic and Clinical Outcomes

    Directory of Open Access Journals (Sweden)

    Antoine G. Tohmeh

    2012-01-01

    Full Text Available Introduction. Extreme lateral interbody fusion (XLIF is a minimally disruptive alternative for anterior lumbar interbody fusion. Recently, synthetic and allograft materials have been increasingly used to eliminate donor-site pain and complications secondary to autogenous bone graft harvesting. The clinical use of allograft cellular bone graft has potential advantages over autograft by eliminating the need to harvest autograft while mimicking autograft's biologic function. The objective of this study was to examine 12-month radiographic and clinical outcomes in patients who underwent XLIF with Osteocel Plus, one such allograft cellular bone matrix. Methods. Forty (40 patients were treated at 61 levels with XLIF and Osteocel Plus and included in the analysis. Results. No complications were observed. From preoperative to 12-month postoperative followup, ODI improved 41%, LBP improved 55%, leg pain improved 43.3%, and QOL (SF-36 improved 56%. At 12 months, 92% reported being “very” or “somewhat” satisfied with their outcome and 86% being either “very” or “somewhat likely” to choose to undergo the procedure again. Complete fusion was observed in 90.2% (55/61 of XLIF levels. Conclusions. Complete interbody fusion with Osteocel Plus was shown in 90.2% of XLIF levels, with the remaining 9.8% being partially consolidated and progressing towards fusion at 12 months.

  9. Segmental and global lordosis changes with two-level axial lumbar interbody fusion and posterior instrumentation

    Science.gov (United States)

    Melgar, Miguel A; Tobler, William D; Ernst, Robert J; Raley, Thomas J; Anand, Neel; Miller, Larry E; Nasca, Richard J

    2014-01-01

    Background Loss of lumbar lordosis has been reported after lumbar interbody fusion surgery and may portend poor clinical and radiographic outcome. The objective of this research was to measure changes in segmental and global lumbar lordosis in patients treated with presacral axial L4-S1 interbody fusion and posterior instrumentation and to determine if these changes influenced patient outcomes. Methods We performed a retrospective, multi-center review of prospectively collected data in 58 consecutive patients with disabling lumbar pain and radiculopathy unresponsive to nonsurgical treatment who underwent L4-S1 interbody fusion with the AxiaLIF two-level system (Baxano Surgical, Raleigh NC). Main outcomes included back pain severity, Oswestry Disability Index (ODI), Odom's outcome criteria, and fusion status using flexion and extension radiographs and computed tomography scans. Segmental (L4-S1) and global (L1-S1) lumbar lordosis measurements were made using standing lateral radiographs. All patients were followed for at least 24 months (mean: 29 months, range 24-56 months). Results There was no bowel injury, vascular injury, deep infection, neurologic complication or implant failure. Mean back pain severity improved from 7.8±1.7 at baseline to 3.3±2.6 at 2 years (p lordosis, defined as a change in Cobb angle ≤ 5°, was identified in 84% of patients at L4-S1 and 81% of patients at L1-S1. Patients with loss or gain in segmental or global lordosis experienced similar 2-year outcomes versus those with less than a 5° change. Conclusions/Clinical Relevance Two-level axial interbody fusion supplemented with posterior fixation does not alter segmental or global lordosis in most patients. Patients with postoperative change in lordosis greater than 5° have similarly favorable long-term clinical outcomes and fusion rates compared to patients with less than 5° lordosis change. PMID:25694920

  10. Minimally invasive transforaminal lumbar interbody fusion for spondylolisthesis and degenerative spondylosis: 5-year results.

    Science.gov (United States)

    Park, Yung; Ha, Joong Won; Lee, Yun Tae; Sung, Na Young

    2014-06-01

    Multiple studies have reported favorable short-term results after treatment of spondylolisthesis and other degenerative lumbar diseases with minimally invasive transforaminal lumbar interbody fusion. However, to our knowledge, results at a minimum of 5 years have not been reported. We determined (1) changes to the Oswestry Disability Index, (2) frequency of radiographic fusion, (3) complications and reoperations, and (4) the learning curve associated with minimally invasive transforaminal lumbar interbody fusion at minimum 5-year followup. We reviewed our first 124 patients who underwent minimally invasive transforaminal lumbar interbody fusion to treat low-grade spondylolisthesis and degenerative lumbar diseases and did not need a major deformity correction. This represented 63% (124 of 198) of the transforaminal lumbar interbody fusion procedures we performed for those indications during the study period (2003-2007). Eighty-three (67%) patients had complete 5-year followup. Plain radiographs and CT scans were evaluated by two reviewers. Trends of surgical time, blood loss, and hospital stay over time were examined by logarithmic curve fit-regression analysis to evaluate the learning curve. At 5 years, mean Oswestry Disability Index improved from 60 points preoperatively to 24 points and 79 of 83 patients (95%) had improvement of greater than 10 points. At 5 years, 67 of 83 (81%) achieved radiographic fusion, including 64 of 72 patients (89%) who had single-level surgery. Perioperative complications occurred in 11 of 124 patients (9%), and another surgical procedure was performed in eight of 124 patients (6.5%) involving the index level and seven of 124 patients (5.6%) at adjacent levels. There were slowly decreasing trends of surgical time and hospital stay only in single-level surgery and almost no change in intraoperative blood loss over time, suggesting a challenging learning curve. Oswestry Disability Index scores improved for patients with spondylolisthesis

  11. Early benefits of minimally invasive transforaminal lumbar interbody fusion in comparison with the traditional open procedure

    Directory of Open Access Journals (Sweden)

    Gregor Rečnik

    2015-06-01

    Full Text Available AbstractBackgroundLumbar interbody fusion is a standard operative procedure in orthopedic spine surgery. Morphological and functional changes in the multifidus muscle after an open procedure have led to the development of a minimally invasive technique, after which no such muscle changes were observed. MethodsSixty-four patients, with clinical and radiological criteria for one-level transforaminal lumbar interbody fusion were enrolled in our prospective randomized study between December 2011 and March 2014. They were randomized into two groups: open approach (33 patients vs. minimally invasive approach (31 patients; one patient was excluded from each group due to postoperative complications. Independent samples T-test was used to compare average values of increase in creatin kinase (CK, which is an enzymatic marker of muscle injury, average surgical time, loss of blood during and after surgery, back pain according to the Visual Analogue Scale (VAS and day of discharge from the hospital. ResultsStatistically important (P< 0.001 lower blood loss (188 ml vs. 527 ml total, less CK increase (15 ukat/L vs. 29 ukat/L, lower VAS score after surgery (7.3 vs. 8.7 and earlier discharge from the hospital (3.5 days vs. 5.2 days were observed in the minimally invasive transforaminal lumbar interbody fusion group. No significant difference in average surgical time was recorded. Conclusions Our results suggest, that minimally invasive transforaminal lumbar interbody fusion causes is associated with less muscle damage, lower blood loss, less post surgical pain and faster early rehabilitation, which is in accordance with previous studies.

  12. Titanium vs. polyetheretherketone (PEEK) interbody fusion: Meta-analysis and review of the literature.

    Science.gov (United States)

    Seaman, Scott; Kerezoudis, Panagiotis; Bydon, Mohamad; Torner, James C; Hitchon, Patrick W

    2017-10-01

    Spinal interbody fusion is a standard and accepted method for spinal fusion. Interbody fusion devices include titanium (Ti) and polyetheretherketone (PEEK) cages with distinct biomechanical properties. Titanium and PEEK cages have been evaluated in the cervical and lumbar spine, with conflicting results in bony fusion and subsidence. Using Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines, we reviewed the available literature evaluating Ti and PEEK cages to assess subsidence and fusion rates. Six studies were included in the analysis, 3 of which were class IV evidence, 2 were class III, and 1 was class II. A total of 410 patients (Ti-228, PEEK-182) and 587 levels (Ti-327, PEEK-260) were studied. Pooled mean age was 50.8years in the Ti group, and 53.1years in the PEEK group. Anterior cervical discectomy was performed in 4 studies (395 levels) and transforaminal interbody fusion in 2 studies (192 levels). No statistically significant difference was found between groups with fusion (OR 1.16, 95% C.I 0.59-2.89, p=0.686, I 2 =49.7%) but there was a statistically significant the rate of subsidence with titanium (OR 3.59, 95% C.I 1.28-10.07, p=0.015, I 2 =56.9%) at last follow-up. Titanium and PEEK cages are associated with a similar rate of fusion, but there is an increased rate of subsidence with titanium cage. Future prospective randomized controlled trials are needed to further evaluate these cages using surgical and patient-reported outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. AxiaLIF system: minimally invasive device for presacral lumbar interbody spinal fusion.

    Science.gov (United States)

    Rapp, Steven M; Miller, Larry E; Block, Jon E

    2011-01-01

    Lumbar fusion is commonly performed to alleviate chronic low back and leg pain secondary to disc degeneration, spondylolisthesis with or without concomitant lumbar spinal stenosis, or chronic lumbar instability. However, the risk of iatrogenic injury during traditional anterior, posterior, and transforaminal open fusion surgery is significant. The axial lumbar interbody fusion (AxiaLIF) system is a minimally invasive fusion device that accesses the lumbar (L4-S1) intervertebral disc spaces via a reproducible presacral approach that avoids critical neurovascular and musculoligamentous structures. Since the AxiaLIF system received marketing clearance from the US Food and Drug Administration in 2004, clinical studies of this device have reported high fusion rates without implant subsidence, significant improvements in pain and function, and low complication rates. This paper describes the design and approach of this lumbar fusion system, details the indications for use, and summarizes the clinical experience with the AxiaLIF system to date.

  14. One-Level or Multilevel Interbody Fusion for Multilevel Lumbar Degenerative Diseases: A Prospective Randomized Control Study with a 4-Year Follow-Up.

    Science.gov (United States)

    Li, Tiefeng; Shi, Lei; Luo, Yibin; Chen, Deyu; Chen, Yu

    2018-02-01

    The treatment of multilevel lumbar degenerative disease (LDD) is complicated and challenging, and the optimal surgical strategy remains controversial. To compare the differences in clinical and radiologic outcomes and in complications after 1-level interbody fusion versus multilevel interbody fusion for the treatment of multilevel LDD. A total of 100 patients with multilevel LDD were randomized in a 1:1 ratio into the 1-level interbody fusion group or the multilevel interbody fusion group. Clinical and radiologic results and major complications in the 2 groups were analyzed. Clinical outcomes were assessed using the Visual Analog Scale for radicular and back pain, the Oswestry Disability Index, and the short-form 36 physical score. Clinical status was assessed by the Whitecloud classification. Radiologic evaluation included assessment of lumbar lordosis, pelvic incidence, and sacral slope. There were no significant differences in clinical and radiologic results between the 2 groups. Procedure duration and intraoperative blood loss were significantly greater in the multilevel interbody fusion group than in the 1-level interbody fusion group; the multilevel interbody fusion group also had greater incidences of temporary nerve root palsy, wound infection, and adjacent segment disease. A hybrid technique including 1-level interbody fusion and multilevel posterolateral fusion is recommended for patients with multilevel LDD. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Clinical outcome of stand-alone ALIF compared to posterior instrumentation for degenerative disc disease

    DEFF Research Database (Denmark)

    Udby, Peter M.; Bech-Azeddine, Rachid

    2015-01-01

    The objective of the article was to: a) present results from a case cohort pilot study comparing stand-alone ALIF and TLIF and, b) review the literature on studies comparing the clinical outcome of stand-alone ALIF with posterior instrumentation including TLIF or PLIF, in patients with disabling...... low back pain resulting from degenerative disc disease. ALIF surgery has previously been linked with certain high risk complications and unfavorable long term fusion results. Newer studies suggest that stand-alone ALIF can possibly be advantageous compared to other types of posterior instrumented...

  16. Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Perspective on Current Evidence and Clinical Knowledge

    Directory of Open Access Journals (Sweden)

    Ali Habib

    2012-01-01

    Full Text Available This paper reviews the current published data regarding open transforaminal lumbar interbody fusion (TLIF in relation to minimally invasive transforaminal lumbar interbody fusion (MI-TLIF. Introduction. MI-TLIF, a modern method for lumbar interbody arthrodesis, has allowed for a minimally invasive method to treat degenerative spinal pathologies. Currently, there is limited literature that compares TLIF directly to MI-TLIF. Thus, we seek to discuss the current literature on these techniques. Methods. Using a PubMed search, we reviewed recent publications of open and MI-TLIF, dating from 2002 to 2012. We discussed these studies and their findings in this paper, focusing on patient-reported outcomes as well as complications. Results. Data found in 14 articles of the literature was analyzed. Using these reports, we found mean follow-up was 20 months. The mean patient study size was 52. Seven of the articles directly compared outcomes of open TLIF with MI-TLIF, such as mean duration of surgery, length of post-operative stay, blood loss, and complications. Conclusion. Although high-class data comparing these two techniques is lacking, the current evidence supports MI-TLIF with outcomes comparable to that of the traditional, open technique. Further prospective, randomized studies will help to further our understanding of this minimally invasive technique.

  17. Stand-alone photovoltaic applications. Lessons learned

    International Nuclear Information System (INIS)

    Loois, G.; Van Hemert, B.

    1999-02-01

    The IEA Photovoltaic Power Systems Programme (PVPS) is one of the collaborative R and D agreements established within the IEA. The objective of Task III is to promote and facilitate the exchange of information and experiences in the field of PV Systems in Stand-alone and Island Applications (SAPV). The book focuses on the practical experiences gained, and does not aim to provide a complete manual on SAPV. When Task III started its activities in 1993, a collection of 50 'State of the art' projects was published in the book 'Examples of Stand-Alone Photovoltaic Systems'. This publication marked the base line for the work of the task. Now, in 1998, the showcases from each country demonstrate the lessons learned in five years of cooperation. The book consists of two parts. The first part contains eight chapters dealing with a specific aspect of stand-alone PV. The second part introduces 14 national showcase projects in a systematic presentation. Each chapter and showcase can be read independently from the rest of the book. Chapter 2, contributed by The Netherlands, analyses the market for stand-alone PV systems. It gives an overview of the 'traditional' application of stand-alone PV, which is the electrification of remote buildings and which has been addressed in depth in other publications. The focus is on the market niches of service applications that are also interesting for more densely populated areas, e.g. in industrialised countries. The United Kingdom illustrates the economic aspects in Chapter 3. Cost comparisons are made, but more important is the illustration of the non-financial considerations that make PV the preferred choice as a power source for many applications. Switzerland explores in Chapter 4 (financing aspects) different financing mechanisms, and financial policies used to overcome the initial cost barrier. Most of these approaches have been applied in developing countries rather than in the western world. Using various examples from all over the

  18. Do Lordotic Cages Provide Better Segmental Lordosis Versus Nonlordotic Cages in Lateral Lumbar Interbody Fusion (LLIF)?

    Science.gov (United States)

    Sembrano, Jonathan N; Horazdovsky, Ryan D; Sharma, Amit K; Yson, Sharon C; Santos, Edward R G; Polly, David W

    2017-05-01

    A retrospective comparative radiographic review. To evaluate the radiographic changes brought about by lordotic and nonlordotic cages on segmental and regional lumbar sagittal alignment and disk height in lateral lumbar interbody fusion (LLIF). The effects of cage design on operative level segmental lordosis in posterior interbody fusion procedures have been reported. However, there are no studies comparing the effect of sagittal implant geometry in LLIF. This is a comparative radiographic analysis of consecutive LLIF procedures performed with use of lordotic and nonlordotic interbody cages. Forty patients (61 levels) underwent LLIF. Average age was 57 years (range, 30-83 y). Ten-degree lordotic PEEK cages were used at 31 lumbar interbody levels, and nonlordotic cages were used at 30 levels. The following parameters were measured on preoperative and postoperative radiographs: segmental lordosis; anterior and posterior disk heights at operative level; segmental lordosis at supra-level and subjacent level; and overall lumbar (L1-S1) lordosis. Measurement changes for each cage group were compared using paired t test analysis. The use of lordotic cages in LLIF resulted in a significant increase in lordosis at operative levels (2.8 degrees; P=0.01), whereas nonlordotic cages did not (0.6 degrees; P=0.71) when compared with preoperative segmental lordosis. Anterior and posterior disk heights were significantly increased in both groups (Plordosis (lordotic P=0.86 vs. nonlordotic P=0.25). Lordotic cages provided significant increase in operative level segmental lordosis compared with nonlordotic cages although overall lumbar lordosis remained unchanged. Anterior and posterior disk heights were significantly increased by both cages, providing basis for indirect spinal decompression.

  19. Single-stage transforaminal decompression, debridement, interbody fusion, and posterior instrumentation for lumbosacral brucellosis.

    Science.gov (United States)

    Abulizi, Yakefu; Liang, Wei-Dong; Muheremu, Aikeremujiang; Maimaiti, Maierdan; Sheng, Wei-Bin

    2017-07-14

    Spinal brucellosis is a less commonly reported infectious spinal pathology. There are few reports regarding the surgical treatment of spinal brucellosis in existing literature. This retrospective study was conducted to determine the effectiveness of single-stage transforaminal decompression, debridement, interbody fusion, and posterior instrumentation for lumbosacral spinal brucellosis. From February 2012 to April 2015, 32 consecutive patients (19 males and 13 females, mean age 53.7 ± 8.7) with lumbosacral brucellosis treated by transforaminal decompression, debridement, interbody fusion, and posterior instrumentation were enrolled. Medical records, imaging studies, laboratory data were collected and summarized. Surgical outcomes were evaluated based on visual analogue scale (VAS), Oswestry Disability Index (ODI) and Japanese Orthopaedic Association (JOA) scale. The changes in C-reactive protein (CRP) levels, erythrocyte sedimentation rate (ESR), clinical symptoms and complications were investigated. Graft fusion was evaluated using Bridwell grading criteria. The mean follow-up period was 24.9 ± 8.2 months. Back pain and radiating leg pain was relieved significantly in all patients after operation. No implant failures were observed in any patients. Wound infection was observed in two patients and sinus formation was observed in one patient. Solid bony fusion was achieved in 30 patients and the fusion rate was 93.8%. The levels of ESR and CRP were returned to normal by the end of three months' follow-up. VAS and ODI scores were significantly improved (P brucellosis.

  20. Comparison of Clinical and Radiologic Results of Mini-Open Transforaminal Lumbar Interbody Fusion and Extreme Lateral Interbody Fusion Indirect Decompression for Degenerative Lumbar Spondylolisthesis.

    Science.gov (United States)

    Kono, Yutaka; Gen, Hogaku; Sakuma, Yoshio; Koshika, Yasuhide

    2018-04-01

    Retrospective study. In this study, we compared the postoperative outcomes of extreme lateral interbody fusion (XLIF) indirect decompression with that of mini-open transforaminal lumbar interbody fusion (TLIF) in patients with lumbar degenerative spondylolisthesis. There are very few reports examining postoperative results of XLIF and minimally invasive TLIF for degenerative lumbar spondylolisthesis, and no reports comparing XLIF and mini-open TLIF. Forty patients who underwent 1-level spinal fusion, either by XLIF indirect decompression (X group, 20 patients) or by mini-open TLIF (T group, 20 patients), for treatment of lumbar degenerative spondylolisthesis were included in this study. Invasiveness of surgery was evaluated on the basis of surgery time, blood loss, hospitalization period, and perioperative complications. The Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ), disc angle (DA), disc height (DH), and slipping length (SL) were evaluated before surgery, immediately after surgery, and at 12 months after surgery. Cross-sectional spinal canal area (CSA) was also measured before surgery and at 1 month after surgery. There was no significant difference between the groups in terms of surgery time or hospitalization period; however, X group showed a significant decrease in blood loss ( p X group ( p <0.05), and the changes in DA and SL were not significantly different between the two groups. The change in CSA was significantly greater in the T group ( p <0.001). Postoperative clinical results were equally favorable for both procedures; however, in comparison with mini-open TLIF, less blood loss and greater correction of DH were observed in XLIF.

  1. Transforaminal lumbar interbody fusion versus posterolateral fusion in degenerative lumbar spondylosis

    Science.gov (United States)

    Zhang, Bin-Fei; Ge, Chao-Yuan; Zheng, Bo-Long; Hao, Ding-Jun

    2016-01-01

    Abstract Objective: The aim of the study was to evaluate the efficacy and safety of transforaminal lumbar interbody fusion (TLIF) versus posterolateral fusion (PLF) in degenerative lumbar spondylosis. Methods: A systematic literature review was performed to obtain randomized controlled trials (RCTs) and observational studies (OSs) of TLIF and PLF for degenerative lumbar spondylosis. Trials performed before November 2015 were retrieved from the Medline, EMBASE, Cochrane library, and Chinese databases. Data extraction and quality evaluation of the trials were performed independently by 2 investigators. A meta-analysis was performed using STATA version 12.0. Results: Two RCTs and 5 OSs of 630 patients were included. Of these subjects, 325 were in the TLIF and 305 were in the PLF group. Results showed that TLIF did not increase the fusion rate based on RCTs (relative risk [RR] = 1.06; 95% confidence interval [CI]: 0.95–1.18; P = 0.321), but increased it based on OSs (RR = 1.14; 95% CI: 1.07–1.23; P = 0.000) and overall (RR = 1.11; 95% CI: 1.05–1.18; P = 0.001) as compared with PLF. TLIF was able to improve the clinical outcomes based on 1 RCT (RR = 1.33; 95% CI: 1.11–1.59, P = 0.002) and overall (RR = 1.19; 95% CI: 1.07–1.33; P = 0.001), but not based on OSs (RR = 1.11; 95% CI: 0.97–1.27; P = 0.129) as compared with PLF. There were no differences between TLIF and PLF in terms of visual analogue scale, Oswestry Disability Index, reoperation, complications, duration of surgical procedure, blood loss, and hospitalization. Conclusions: In conclusion, evidence is not sufficient to support that TLIF provides higher fusion rate than PLF, and this poor evidence indicates that TLIF might improve only clinical outcomes. Higher quality, multicenter RCTs are needed to better define the role of TLIF and PLF. PMID:27749558

  2. Transforaminal lumbar interbody fusion versus posterolateral fusion in degenerative lumbar spondylosis: A meta-analysis.

    Science.gov (United States)

    Zhang, Bin-Fei; Ge, Chao-Yuan; Zheng, Bo-Long; Hao, Ding-Jun

    2016-10-01

    The aim of the study was to evaluate the efficacy and safety of transforaminal lumbar interbody fusion (TLIF) versus posterolateral fusion (PLF) in degenerative lumbar spondylosis. A systematic literature review was performed to obtain randomized controlled trials (RCTs) and observational studies (OSs) of TLIF and PLF for degenerative lumbar spondylosis. Trials performed before November 2015 were retrieved from the Medline, EMBASE, Cochrane library, and Chinese databases. Data extraction and quality evaluation of the trials were performed independently by 2 investigators. A meta-analysis was performed using STATA version 12.0. Two RCTs and 5 OSs of 630 patients were included. Of these subjects, 325 were in the TLIF and 305 were in the PLF group. Results showed that TLIF did not increase the fusion rate based on RCTs (relative risk [RR] = 1.06; 95% confidence interval [CI]: 0.95-1.18; P = 0.321), but increased it based on OSs (RR = 1.14; 95% CI: 1.07-1.23; P = 0.000) and overall (RR = 1.11; 95% CI: 1.05-1.18; P = 0.001) as compared with PLF. TLIF was able to improve the clinical outcomes based on 1 RCT (RR = 1.33; 95% CI: 1.11-1.59, P = 0.002) and overall (RR = 1.19; 95% CI: 1.07-1.33; P = 0.001), but not based on OSs (RR = 1.11; 95% CI: 0.97-1.27; P = 0.129) as compared with PLF. There were no differences between TLIF and PLF in terms of visual analogue scale, Oswestry Disability Index, reoperation, complications, duration of surgical procedure, blood loss, and hospitalization. In conclusion, evidence is not sufficient to support that TLIF provides higher fusion rate than PLF, and this poor evidence indicates that TLIF might improve only clinical outcomes. Higher quality, multicenter RCTs are needed to better define the role of TLIF and PLF.

  3. Rational decision making in a wide scenario of different minimally invasive lumbar interbody fusion approaches and devices.

    Science.gov (United States)

    Pimenta, Luiz; Tohmeh, Antoine; Jones, David; Amaral, Rodrigo; Marchi, Luis; Oliveira, Leonardo; Pittman, Bruce C; Bae, Hyun

    2018-03-01

    With the proliferation of a variety of modern MIS spine surgery procedures, it is mandatory that the surgeon dominate all aspects involved in surgical indication. The information related to the decision making in patient selection for specific procedures is mandatory for surgical success. The objective of this study is to present decision-making criteria in minimally invasive surgery (MIS) selection for a variety of patients and pathologies. In this article, practicing surgeons who specialize in various MIS approaches for spinal fusion were engaged to provide expert opinion and literature review on decision making criteria for several MIS procedures. Pros, cons, relative limitations, and case examples are provided for patient selection in treatment with MIS posterolateral fusion (MIS-PLF), mini anterior lumbar interbody fusion (mini-ALIF), lateral interbody fusion (LLIF), MIS posterior lumbar interbody fusion (MIS-PLIF) and MIS transforaminal lumbar interbody fusion (MIS-TLIF). There is a variety of aspects to consider when deciding which modern MIS surgical approach is most appropriate to use based on patient and pathologic characteristics. The surgeon must adapt them to the characteristic of each type of patients, helping them to choose the most effective and efficient therapeutic option for each case.

  4. An analysis of postoperative thigh symptoms after minimally invasive transpsoas lumbar interbody fusion.

    Science.gov (United States)

    Cummock, Matthew D; Vanni, Steven; Levi, Allan D; Yu, Yong; Wang, Michael Y

    2011-07-01

    The minimally invasive transpsoas interbody fusion technique requires dissection through the psoas muscle, which contains the nerves of the lumbosacral plexus posteriorly and genitofemoral nerve anteriorly. Retraction of the psoas is becoming recognized as a cause of transient postoperative thigh pain, numbness, paresthesias, and weakness. However, few reports have described the nature of thigh symptoms after this procedure. The authors performed a review of patients who underwent the transpsoas technique for lumbar spondylotic disease, disc degeneration, and spondylolisthesis treated at a single academic medical center. A review of patient charts, including the use of detailed patient-driven pain diagrams performed at equal preoperative and follow-up intervals, investigated the survival of postoperative thigh pain, numbness, paresthesias, and weakness of the iliopsoas and quadriceps muscles in the follow-up period on the ipsilateral side of the surgical approach. Over a 3.2-year period, 59 patients underwent transpsoas interbody fusion surgery. Of these, 62.7% had thigh symptoms postoperatively. New thigh symptoms at first follow-up visit included the following: burning, aching, stabbing, or other pain (39.0%); numbness (42.4%); paresthesias (11.9%); and weakness (23.7%). At 3 months postoperatively, these percentages decreased to 15.5%, 24.1%, 5.6%, and 11.3%, respectively. Within the patient sample, 44% underwent a 1-level, 41% a 2-level, and 15% a 3-level transpsoas operation. While not statistically significant, thigh pain, numbness, and weakness were most prevalent after L4-5 transpsoas interbody fusion at the first postoperative follow-up. The number of lumbar levels that were surgically treated had no clear association with thigh symptoms but did correlate directly with surgical time, intraoperative blood loss, and length of hospital stay. Transpsoas interbody fusion is associated with high rates of immediate postoperative thigh symptoms. While larger

  5. Combined posteroanterior fusion versus transforaminal lumbar interbody fusion (TLIF) in thoracolumbar burst fractures.

    Science.gov (United States)

    Schmid, Rene; Lindtner, Richard Andreas; Lill, Markus; Blauth, Michael; Krappinger, Dietmar; Kammerlander, Christian

    2012-04-01

    The optimal treatment strategy for burst fractures of the thoracolumbar junction is discussed controversially in the literature. Whilst 360° fusion has shown to result in better radiological outcome, recent studies have failed to show its superiority concerning clinical outcome. The morbidity associated with the additional anterior approach may account for these findings. The aim of this prospective observational study was therefore to compare two different techniques for 360° fusion in thoracolumbar burst fractures using either thoracoscopy or a transforaminal approach (transforaminal lumbar interbody fusion (TLIF)) to support the anterior column. Posterior reduction and short-segmental fixation using angular stable pedicle screw systems were performed in all patients as a first step. Monocortical strut grafts were used for the anterior support in the TLIF group, whilst tricortical grafts or titanium vertebral body replacing implants of adjustable height were used in the combined posteroanterior group. At final follow-up, the radiological outcome was assessed by performing X-rays in a standing position. The clinical outcome was measured using five validated outcome scores. The morbidity associated with the approaches and the donor site was assessed as well. There were 21 patients in the TLIF group and 14 patients in the posteroanterior group included. The postoperative loss of correction was higher in the TLIF group (4.9°±8.3° versus 3.4°±6.4°, p>0.05). There were no significant differences regarding the outcome scores between the two groups. There were no differences in terms of return to employment, leisure activities and back function either. More patients suffered from donor-site morbidity in the TLIF group, whilst the morbidity associated with the surgical approach was higher in the posteroanterior group. The smaller donor-site morbidity in the posteroanterior group is counterbalanced by an additional morbidity associated with the anterior approach

  6. Minimally Invasive Transforaminal Lumbar Interbody Fusion and Unilateral Fixation for Degenerative Lumbar Disease.

    Science.gov (United States)

    Wang, Hui-Wang; Hu, Yong-Cheng; Wu, Zhan-Yong; Wu, Hua-Rong; Wu, Chun-Fu; Zhang, Lian-Suo; Xu, Wei-Kun; Fan, Hui-Long; Cai, Jin-Sheng; Ma, Jian-Qing

    2017-08-01

    To evaluate the clinical effect of the minimally invasive transforaminal lumbar interbody fusion combined with posterolateral fusion and unilateral fixation using a tubular retractor in the management of degenerative lumbar disease. A retrospective analysis was conducted to analyze the clinical outcome of 58 degenerative lumbar disease patients who were treated with minimally invasive transforaminal lumbar interbody fusion combined with posterolateral fusion and unilateral fixation during December 2012 to January 2015. The spine was unilaterally approached through a 3.0-cm skin incision centered on the disc space, located 2.5 cm lateral to the midline, and the multifidus muscles and longissimus dorsi were stripped off. After transforaminal lumbar interbody fusion and posterolateral fusion the unilateral pedicle screw fixation was performed. The visual analogue scale (VAS) for back and leg pain, the Oswestry disability index (ODI), and the MacNab score were applied to evaluate clinical effects. The operation time, peri-operative bleeding, postoperative time in bed, hospitalization costs, and the change in the intervertebral height were analyzed. Radiological fusion based on the Bridwell grading system was also assessed at the last follow-up. The quality of life of the patients before and after the operation was assessed using the short form-36 scale (SF-36). Fifty-eight operations were successfully performed, and no nerve root injury or dural tear occurred. The average operation time was 138 ± 33 min, intraoperative blood loss was 126 ± 50 mL, the duration from surgery to getting out of bed was 46 ± 8 h, and hospitalization cost was 1.6 ± 0.2 ten thousand yuan. All of the 58 patients were followed up for 7-31 months, with an average of 14.6 months. The postoperative VAS scores and ODI score were significantly improved compared with preoperative data (P degenerative lumbar disease, and the short-term clinical outcome is satisfactory

  7. A comparison of anterior cervical discectomy and fusion (ACDF) using self-locking stand-alone polyetheretherketone (PEEK) cage with ACDF using cage and plate in the treatment of three-level cervical degenerative spondylopathy: a retrospective study with 2-year follow-up.

    Science.gov (United States)

    Chen, Yuqiao; Lü, Guohua; Wang, Bing; Li, Lei; Kuang, Lei

    2016-07-01

    To evaluate the clinical efficacy and radiological outcomes of anterior cervical discectomy and fusion (ACDF) using self-locking polyetheretherketone (PEEK) cages for treatment of three-level cervical degenerative spondylopathy. Twenty-eight patients underwent three-level ACDF using self-locking stand-alone PEEK cages (group A), and 26 patients underwent three-level ACDF using cages and plate fixation (group B) were reviewed retrospectively. Clinical efficacy was evaluated by pre- and post-operative Japanese Orthopedic Association (JOA) scores and Neck Disability Index (NDI). The operation time, blood loss, surgical results according to Odom's criteria and post-operative dysphagia status were also recorded. Radiological outcomes including fusion, cervical Cobb's lordosis, fused segment angle, disc height, and cage subsidence were assessed. Clinical outcome measures such as dysphagia and fusion rate and the results of surgery evaluated according to Odom's criteria were not statistically significant (P > 0.05) between groups. The operation time was shorter and blood loss was less in group A (P  0.05). Post-operative cage subsidence, the loss of disc height, cervical lordosis and the fused segment angle were relatively higher in group A than group B (P < 0.05). ACDF using self-locking stand-alone cages showed similar clinical results as compared to ACDF using cages and plate fixation for the treatment of three-level cervical degenerative spondylopathy. However, potential long-term problems such as cage subsidence, loss of cervical lordosis and fused segment angle post-operatively were shown to be associated with patients who underwent ACDF using self-locking stand-alone cages.

  8. Investigation of different cage designs and mechano-regulation algorithms in the lumbar interbody fusion process - a finite element analysis.

    Science.gov (United States)

    Postigo, Sergio; Schmidt, Hendrik; Rohlmann, Antonius; Putzier, Michael; Simón, Antonio; Duda, Georg; Checa, Sara

    2014-04-11

    Lumbar interbody fusion cages are commonly used to treat painful spinal degeneration and instability by achieving bony fusion. Many different cage designs exist, however the effect of cage morphology and material properties on the fusion process remains largely unknown. This finite element model study aims to investigate the influence of different cage designs on bone fusion using two mechano-regulation algorithms of tissue formation. It could be observed that different cages play a distinct key role in the mechanical conditions within the fusion region and therefore regulate the time course of the fusion process. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Axial lumbar interbody fusion: a 6-year single-center experience

    Directory of Open Access Journals (Sweden)

    Zeilstra DJ

    2013-08-01

    Full Text Available Dick J Zeilstra,1 Larry E Miller,2,3 Jon E Block3 1Bergman Clinics, Naarden and NedSpine, Ede, The Netherlands; 2Miller Scientific Consulting, Inc, Arden, NC, USA; 3The Jon Block Group, San Francisco, CA, USA Introduction: The aim of this study is to report our 6-year single-center experience with L5–S1 axial lumbar interbody fusion (AxiaLIF. Methods: A total of 131 patients with symptomatic degenerative disc disease refractory to nonsurgical treatment were treated with AxiaLIF at L5–S1, and were followed for a minimum of 1 year (mean: 21 months. Main outcomes included back and leg pain severity, Oswestry Disability Index score, working status, analgesic medication use, patient satisfaction, and complications. Computed tomography was used to determine postoperative fusion status. Results: No intraoperative complications, including vascular, neural, urologic, or bowel injuries, were reported. Back and leg pain severity decreased by 51% and 42%, respectively, during the follow-up period (both P < 0.001. Back function scores improved 50% compared to baseline. Clinical success, defined as improvement ≥30%, was 67% for back pain severity, 65% for leg pain severity, and 71% for back function. The employment rate increased from 47% before surgery to 64% at final follow-up (P < 0.001. Less than one in four patients regularly used analgesic medications postsurgery. Patient satisfaction with the AxiaLIF procedure was 83%. The fusion rate was 87.8% at final follow-up. During follow-up, 17 (13.0% patients underwent 18 reoperations on the lumbar spine, including pedicle screw fixation (n = 10, total disc replacement of an uninvolved level (n = 3, facet screw fixation (n = 3, facet screw removal (n = 1, and interbody fusion at L4–L5 (n = 1. Eight (6.1% reoperations were at the index level. Conclusion: Single-level AxiaLIF is a safe and effective means to achieve lumbosacral fusion in patients with symptomatic degenerative disc disease. Keywords: Axia

  10. Clinical Outcomes of Extreme Lateral Interbody Fusion in the Treatment of Adult Degenerative Scoliosis

    Directory of Open Access Journals (Sweden)

    Adam M. Caputo

    2012-01-01

    Full Text Available Introduction. The use of extreme lateral interbody fusion (XLIF and other lateral access surgery is rapidly increasing in popularity. However, limited data is available regarding its use in scoliosis surgery. The objective of this study was to evaluate the clinical outcomes of adults with degenerative lumbar scoliosis treated with XLIF. Methods. Thirty consecutive patients with adult degenerative scoliosis treated by a single surgeon at a major academic institution were followed for an average of 14.3 months. Interbody fusion was completed using the XLIF technique with supplemental posterior instrumentation. Validated clinical outcome scores were obtained on patients preoperatively and at most recent follow-up. Complications were recorded. Results. The study group demonstrated improvement in multiple clinical outcome scores. Oswestry Disability Index scores improved from 24.8 to 19.0 (P < 0.001. Short Form-12 scores improved, although the change was not significant. Visual analog scores for back pain decreased from 6.8 to 4.6 (P < 0.001 while scores for leg pain decreased from 5.4 to 2.8 (P < 0.001. A total of six minor complications (20% were recorded, and two patients (6.7% required additional surgery. Conclusions. Based on the significant improvement in validated clinical outcome scores, XLIF is effective in the treatment of adult degenerative scoliosis.

  11. AxiaLIF system: minimally invasive device for presacral lumbar interbody spinal fusion

    Directory of Open Access Journals (Sweden)

    Rapp SM

    2011-08-01

    Full Text Available Steven M Rapp1, Larry E Miller2,3, Jon E Block31Michigan Spine Institute, Waterford, MI, USA; 2Miller Scientific Consulting Inc, Biltmore Lake, NC, USA; 3Jon E. Block, Ph.D., Inc., San Francisco, CA, USAAbstract: Lumbar fusion is commonly performed to alleviate chronic low back and leg pain secondary to disc degeneration, spondylolisthesis with or without concomitant lumbar spinal stenosis, or chronic lumbar instability. However, the risk of iatrogenic injury during traditional anterior, posterior, and transforaminal open fusion surgery is significant. The axial lumbar interbody fusion (AxiaLIF system is a minimally invasive fusion device that accesses the lumbar (L4–S1 intervertebral disc spaces via a reproducible presacral approach that avoids critical neurovascular and musculoligamentous structures. Since the AxiaLIF system received marketing clearance from the US Food and Drug Administration in 2004, clinical studies of this device have reported high fusion rates without implant subsidence, significant improvements in pain and function, and low complication rates. This paper describes the design and approach of this lumbar fusion system, details the indications for use, and summarizes the clinical experience with the AxiaLIF system to date.Keywords: AxiaLIF, fusion, lumbar, minimally invasive, presacral

  12. Developing a mobile stand alone photovoltaic generator

    International Nuclear Information System (INIS)

    Soler-Bientz, R.; Ricalde-Cab, L.O.; Solis-Rodriguez, L.E.

    2006-01-01

    This paper describes a recent work developed to create a mobile stand alone photovoltaic generator that can be easily relocated in remote areas to evaluate the feasibility of photovoltaic energy applications. A set of sensors were installed to monitor the electric current and voltage of the energy generated, the energy stored and the energy used by the loads that may be connected to the system. Other parameters like solar radiations (both on the horizontal and on the photovoltaic generation planes) and temperatures (of both the environment and the photovoltaic module) were monitored. This was done while considering the important role of temperature in the photovoltaic module performance. Finally, a measurement and communication hardware was installed to interface the system developed with a conventional computer. In this way, the performance of the overall system in real rural conditions could be evaluated efficiently. Visual software that reads, visualizes and saves the data generated by the system was also developed by means of the LabVIEW programming environment

  13. Clinical outcome of trans-sacral interbody fusion after partial reduction for high-grade l5-s1 spondylolisthesis.

    Science.gov (United States)

    Smith, J A; Deviren, V; Berven, S; Kleinstueck, F; Bradford, D S

    2001-10-15

    A clinical retrospective study was conducted. To evaluate the clinical and radiographic outcome of reduction followed by trans-sacral interbody fusion for high-grade spondylolisthesis. In situ posterior interbody fusion with fibula allograft has improved the fusion rates for patients with high-grade spondylolisthesis. The use of this technique in conjunction with partial reduction has not been reported. Nine consecutive patients underwent treatment of high-grade (Grade 3 or 4) spondylolisthesis with partial reduction followed by posterior interbody fusion using cortical allograft. The average age at the time of surgery was 27 years (range, 8-51 years), and the average follow-up period was 43 months (range, 24-72 months). Before surgery, eight patients had low back pain, seven patients had radiating leg pain, and five patients had hamstring tightness. The average grade of spondylolisthesis by Meyerding grading was 3.9 (range, 3-5). Charts and radiographs were evaluated, and outcomes were collected by use of the modified SRS outcomes instrument. Radiographic indexes demonstrated significant improvement with partial reduction and fusion. The slip angle, as measured from the inferior endplate of L5, improved from 41.2 degrees (range, 24-82 degrees ) before surgery to 21 degrees (range, 5-40 degrees ) after surgery. All the patients were extremely or somewhat satisfied with surgery. The two patients who underwent this operation without initial instrumentation experienced fractures of their interbody grafts. Both of these patients underwent repair of the pseudarthrosis with placement of trans-sacral pedicle screw instrumentation and subsequent fusion. Partial reduction followed by posterior interbody fusion is an effective technique for the management of high-grade spondylolisthesis in pediatric and adult patient populations, as assessed by radiographic and clinical criteria. Pedicle screw instrumentation with the sacral screws capturing L5 is recommended when this

  14. Does Lordotic Angle of Cage Determine Lumbar Lordosis in Lumbar Interbody Fusion?

    Science.gov (United States)

    Hong, Taek-Ho; Cho, Kyu-Jung; Kim, Young-Tae; Park, Jae-Woo; Seo, Beom-Ho; Kim, Nak-Chul

    2017-07-01

    Retrospective, radiological analysis. To determine that 15° lordotic angle cages create higher lumbar lordosis in open transforaminal lumbar interbody fusion (TLIF) than 4° and 8° cages. Restoration of lumbar lordosis is important to obtain good outcome after lumbar fusion surgery. Various shapes and angles of cages in interbody fusion have been used; however, it is not proved that lordotic angle of cages determine lumbar lordosis. Sixty-seven patients were evaluated after TLIF using 15° cages and screw instrumentation. For comparison, TLIF using 4° lordotic angle cages in 65 patients and 8° cages in 49 patients were analyzed. Lumbar lordosis angles, segmental lordosis angles, disc height, and bony union rate were measured on the radiographs. The lumbar lordosis was 31.1° preoperatively, improved to 42.9° postoperatively, and decreased to 36.4° at the last follow-up in the 15° group. It was 35.8° before surgery, corrected to 41.5° after surgery, and changed to 33.6° at the last follow-up in the 4° group. In the 8° group, it was 32.7° preoperatively, improved to 39.1° postoperatively, and decreased to 34.5° at the last follow-up. These changes showed statistical significances (P lordosis at L4-5 was 6.6° before surgery, 13.1° after surgery, and 9.8° at the last follow-up in the 15° group. It was 6.9°, 9.5°, and 6.2° in the 4° group and 6.7°, 9.8°, and 8.1° in the 8° group, respectively (P lordosis after TLIF. Cages with sufficient lordotic angle showed better restoration of lumbar lordosis and prevention of loss of correction. 4.

  15. Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation in surgical treatment for single-segment lumbar spinal tuberculosis

    OpenAIRE

    Zeng, Hao; Wang, Xiyang; Zhang, Penghui; Peng, Wei; Zhang, Yupeng; Liu, Zheng

    2015-01-01

    Objective: The aim of this study is to determine the feasibility and efficacy of surgical management of single-segment lumbar spinal tuberculosis (TB) by using single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation.Methods: Seventeen cases of single-segment lumbar TB were treated with single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reco...

  16. Spondylectomy and lateral lumbar interbody fusion for thoracolumbar kyphosis in an adult with achondroplasia

    Science.gov (United States)

    Miyazaki, Masashi; Kanezaki, Shozo; Notani, Naoki; Ishihara, Toshinobu; Tsumura, Hiroshi

    2017-01-01

    Abstract Rationale: Fixed thoracolumbar kyphosis with spinal stenosis in adult patients with achondroplasia presents a challenging issue. We describe the first case in which spondylectomy and minimally invasive lateral access interbody arthrodesis were used for the treatment of fixed severe thoracolumbar kyphosis and lumbar spinal canal stenosis in an adult with achondroplasia. Patient concerns: A 61-year-old man with a history of achondroplastic dwarfism presented with low back pain and radiculopathy and neurogenic claudication. Diagnoses: Plain radiographs revealed a high-grade thoracolumbar kyphotic deformity with diffuse degenerative changes in the lumbar spine. The apex was located at L2, the local kyphotic angle from L1 to L3 was 105°, and the anterior area was fused from the L1 to L3 vertebrae. MRI revealed significant canal and lateral recess stenosis secondary to facet hypertrophy. Interventions: We planned a front-back correction of the anterior and posterior spinal elements. We first performed anterior release at the fused part from L1 to L3 and XLIF at L3/4 and L4/5. Next, the patient was placed in the prone position. Spondylectomy at the L2 vertebra and posterior fusion from T10 to L5 were performed. Postoperative radiographs revealed L1 to L3 kyphosis of 32°. Outcomes: No complications occurred during or after surgery. Postoperatively, the patient's low back pain and neurological claudication were resolved. No worsening of kyphosis was observed 24 months postoperatively. Lessons: Circumferential decompression of the spinal cord at the apical vertebral level and decompression of lumbar canal stenosis were necessary. Front-back correction of the anterior and posterior spinal elements via spondylectomy and lateral lumbar interbody fusion is a reasonable surgical option for thoracolumbar kyphosis and developmental canal stenosis in patients with achondroplasia. PMID:29245270

  17. Treatment of Spinal Tuberculosis by Debridement, Interbody Fusion and Internal Fixation via Posterior Approach Only.

    Science.gov (United States)

    Tang, Ming-xing; Zhang, Hong-qi; Wang, Yu-xiang; Guo, Chao-feng; Liu, Jin-yang

    2016-02-01

    Surgical treatment for spinal tuberculosis includes focal tuberculosis debridement, segmental stability reconstruction, neural decompression and kyphotic deformity correction. For the lesions mainly involved anterior and middle column of the spine, anterior operation of debridement and fusion with internal fixation has been becoming the most frequently used surgical technique for the spinal tuberculosis. However, high risk of structural damage might relate with anterior surgery, such as damage in lungs, heart, kidney, ureter and bowel, and the deformity correction is also limited. Due to the organs are in the front of spine, there are less complications in posterior approach. Spinal pedicle screw passes through the spinal three-column structure, which provides more powerful orthopedic forces compared with the vertebral body screw, and the kyphotic deformity correction effect is better in posterior approach. In this paper, we report a 68-year-old male patient with thoracic tuberculosis who underwent surgical treatment by debridement, interbody fusion and internal fixation via posterior approach only. The patient was placed in prone position under general anesthesia. Posterior midline incision was performed, and the posterior spinal construction was exposed. Then place pedicle screw, and fix one side rod temporarily. Make the side of more bone destruction and larger abscess as lesion debridement side. Resect the unilateral facet joint, and retain contralateral structure integrity. Protect the spinal cord, nerve root. Clear sequestrum, necrotic tissue, abscess of paravertebral and intervertebral space. Specially designed titanium mesh cages or bone blocks were implanted into interbody. Fix both side rods and compress both sides to make the mesh cages and bone blocks tight. Reconstruct posterior column structure with allogeneic bone and autologous bone. Using this technique, the procedures of debridement, spinal cord decompression, deformity correction, bone grafting

  18. 39 CFR 122.2 - Stand-alone special services.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Stand-alone special services. 122.2 Section 122.2 Postal Service UNITED STATES POSTAL SERVICE POST OFFICE SERVICES [DOMESTIC MAIL] SERVICE STANDARDS FOR MARKET-DOMINANT SPECIAL SERVICES PRODUCTS § 122.2 Stand-alone special services. (a) The service standard...

  19. Uninstrumented Posterior Lumbar Interbody Fusion: Have Technological Advances in Stabilizing the Lumbar Spine Truly Improved Outcomes?

    Science.gov (United States)

    Prolo, Laura M; Oklund, Sally A; Zawadzki, Nadine; Desai, Manisha; Prolo, Donald J

    2018-04-06

    Since the 1980s, numerous operations have replaced posterior lumbar interbody fusion (PLIF) with human bone. These operations often involve expensive implants and complex procedures. Escalating expenditures in lumbar fusion surgery warrant re-evaluation of classical PLIF with allogeneic ilium and without instrumentation. The purpose of this study was to determine the long-term fusion rate and clinical outcomes of PLIF with allogeneic bone (allo-PLIF). Between 1981 and 2006, 321 patients aged 12-80 years underwent 339 1-level or 2-level allo-PLIFs for degenerative instability and were followed for 1-28 years. Fusion status was determined by radiographs and as available, by computed tomography scans. Clinical outcome was assessed by the Economic/Functional Outcome Scale. Of the 321 patients, 308 were followed postoperatively (average 6.7 years) and 297 (96%) fused. Fusion rates were lower for patients with substance abuse (89%, P = 0.007). Clinical outcomes in 87% of patients were excellent (52%) or good (35%). Economic/Functional Outcome Scale scores after initial allo-PLIF on average increased 5.2 points. Successful fusion correlated with nearly a 2-point gain in outcome score (P = 0.001). A positive association between a patient characteristic and outcome was observed only with age 65 years and greater, whereas negative associations in clinical outcomes were observed with mental illness, substance abuse, heavy stress to the low back, or industrial injuries. The total complication rate was 7%. With 3 decades of follow-up, we found that successful clinical outcomes are highly correlated with solid fusion using only allogeneic iliac bone. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. Posterior Decompression, Lumber Interbody Fusion and Internal Fixation in the Treatment of Upper Lumbar Intervertebral Disc Herniation

    Directory of Open Access Journals (Sweden)

    DONG Zhan

    2014-12-01

    Full Text Available Objective: To assess the clinical outcomes of posterior decompression, interbody fusion and internal fixationfor the treatment of the upper lumbar intervertebral disc herniation. Methods: Twelve patients with the upper lumbar intervertebral disc herniation were treated by posterior decompression, interbosy fusion and internal fixation. The time of the operation, the amount of bleeding and the clinical efficacy were evaluated. Results: The time of operation was (143±36 min and the amount of bleeding during operation was (331.5±47.9 mL. There was no spinal cord and injuries, nerve injury, epidural damage and leakage of cerebrospinal fluid. All patients were followed up for 10~19 months with the average being 12.6 months. The functional scoring of Japanese Orthopedic Association (JOA before the operation was (11.4±3.3 scores and final score after follow-up was (22.9±3.1 scores and there were statistical difference (P<0.01. Lumber interbody fusion of all patients completed successfully and the good rate after the operation was 91.7%. Conclusion: Posterior decompression, interbody fusion and internal fixation for the treatment of the upper lumbar intervertebral disc herniation was characterized by full exposure, safety and significant efficacy.

  1. Digitalized design of extraforaminal lumbar interbody fusion: a computer-based simulation and cadaveric study.

    Directory of Open Access Journals (Sweden)

    Mingjie Yang

    Full Text Available PURPOSE: This study aims to investigate the feasibility of a novel lumbar approach named extraforaminal lumbar interbody fusion (ELIF, a newly emerging minimally invasive technique for treating degenerative lumbar disorders, using a digitalized simulation and a cadaveric study. METHODS: The ELIF surgical procedure was simulated using the Mimics surgical simulator and included dissection of the superior articular process, dilation of the vertebral foramen, and placement of pedicle screws and a cage. ELIF anatomical measures were documented using a digitalized technique and subsequently validated on fresh cadavers. RESULTS: The use of the Mimics allowed for the vivid simulation of ELIF surgical procedures, while the cadaveric study proved the feasibility of this novel approach. ELIF had a relatively lateral access approach that was located 8-9 cm lateral to the median line with an access depth of approximately 9 cm through the intermuscular space. Dissection of the superior articular processes could fully expose the target intervertebral discs and facilitate a more inclined placement of the pedicle screws and cage with robust enhancement. CONCLUSIONS: According to the computer-based simulation and cadaveric study, it is feasible to perform ELIF. Further research including biomechanical study is needed to prove ELIF has a superior ability to preserve the posterior tension bands of the spinal column, with similar effects on spinal decompression, fixation, and fusion, and if it can enhance post-fusion spinal stability and expedites postoperative recovery.

  2. Digitalized design of extraforaminal lumbar interbody fusion: a computer-based simulation and cadaveric study.

    Science.gov (United States)

    Yang, Mingjie; Zeng, Cheng; Guo, Song; Pan, Jie; Han, Yingchao; Li, Zeqing; Li, Lijun; Tan, Jun

    2014-01-01

    This study aims to investigate the feasibility of a novel lumbar approach named extraforaminal lumbar interbody fusion (ELIF), a newly emerging minimally invasive technique for treating degenerative lumbar disorders, using a digitalized simulation and a cadaveric study. The ELIF surgical procedure was simulated using the Mimics surgical simulator and included dissection of the superior articular process, dilation of the vertebral foramen, and placement of pedicle screws and a cage. ELIF anatomical measures were documented using a digitalized technique and subsequently validated on fresh cadavers. The use of the Mimics allowed for the vivid simulation of ELIF surgical procedures, while the cadaveric study proved the feasibility of this novel approach. ELIF had a relatively lateral access approach that was located 8-9 cm lateral to the median line with an access depth of approximately 9 cm through the intermuscular space. Dissection of the superior articular processes could fully expose the target intervertebral discs and facilitate a more inclined placement of the pedicle screws and cage with robust enhancement. According to the computer-based simulation and cadaveric study, it is feasible to perform ELIF. Further research including biomechanical study is needed to prove ELIF has a superior ability to preserve the posterior tension bands of the spinal column, with similar effects on spinal decompression, fixation, and fusion, and if it can enhance post-fusion spinal stability and expedites postoperative recovery.

  3. Standard versus Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Prospective Randomized Study

    Directory of Open Access Journals (Sweden)

    Daniel Serban

    2017-01-01

    Full Text Available Symptomatic spondylolisthesis patients may benefit from surgical decompression and stabilization. The standard (S technique is a transforaminal lumbar interbody fusion (TLIF. Newer, minimally invasive (MI techniques seem to provide similar results with less morbidity. We enrolled patients with at least 6 months of symptoms and image-confirmed low-grade spondylolisthesis, at a single academic institution, between 2011 and 2015. The patients were randomized to either S or MI TLIF. The primary outcome measure was the Oswestry Disability Index (ODI improvement at 1 year. Secondary outcome measures included length of operation, estimated blood loss, length of hospitalization, and fusion rates at 1 year. Forty patients were enrolled in each group. The differences in mean operative time and estimated blood loss were not statistically significant between the two groups. The patients were discharged after surgery at 4.12 days for the S TLIF group and 1.92 days for the MI TLIF group. The ODI improvement was similar and statistically significant in both groups. The fusion was considered solid in 36 (90% of patients at 1 year in both groups. In conclusion, the two techniques provided similar clinical and radiological outcomes at 1 year. The patients undergoing MI TLIF had a shorter hospital stay. This trial is registered with NCT03155789.

  4. Anatomy of the psoas muscle and lumbar plexus with respect to the surgical approach for lateral transpsoas interbody fusion.

    Science.gov (United States)

    Kepler, Christopher K; Bogner, Eric A; Herzog, Richard J; Huang, Russel C

    2011-04-01

    Lateral transpsoas interbody fusion (LTIF) is a minimally invasive technique that permits interbody fusion utilizing cages placed via a direct lateral retroperitoneal approach. We sought to describe the locations of relevant neurovascular structures based on MRI with respect to this novel surgical approach. We retrospectively reviewed consecutive lumbosacral spine MRI scans in 43 skeletally mature adults. MRI scans were independently reviewed by two readers to identify the location of the psoas muscle, lumbar plexus, femoral nerve, inferior vena cava and right iliac vein. Structures potentially at risk for injury were identified by: a distance from the anterior aspect of the adjacent vertebral bodies of muscle and lumbar plexus is described which allows use of the psoas position as a proxy for lumbar plexus position to identify patients who may be at risk, particularly at the L4-5 level. Further study will establish the clinical relevance of these measurements and the ability of neurovascular structures to be retracted without significant injury.

  5. Radiographic Results of Single Level Transforaminal Lumbar Interbody Fusion in Degenerative Lumbar Spine Disease: Focusing on Changes of Segmental Lordosis in Fusion Segment

    OpenAIRE

    Kim, Sang-Bum; Jeon, Taek-Soo; Heo, Youn-Moo; Lee, Woo-Suk; Yi, Jin-Woong; Kim, Tae-Kyun; Hwang, Cheol-Mog

    2009-01-01

    Background To assess the radiographic results in patients who underwent transforaminal lumbar interbody fusion (TLIF), particularly the changes in segmental lordosis in the fusion segment, whole lumbar lordosis and disc height. Methods Twenty six cases of single-level TLIF in degenerative lumbar diseases were analyzed. The changes in segmental lordosis, whole lumbar lordosis, and disc height were evaluated before surgery, after surgery and at the final follow-up. Results The segmental lordosi...

  6. Surgical outcome of posterior lumbar interbody fusion with pedicle screw fixation for lumbar spondylolisthesis

    International Nuclear Information System (INIS)

    Shoda, Motoi; Kuno, Shigehiko; Inoue, Tatsushi

    2009-01-01

    Problems of lumbar spondylolisthesis treatment are many surgical tactics, elderly patient, osteoporosis, complications and recurrence of the symptoms. PLIF (posterior lumbar interbody fusion) and PS (pedicle screw) fixation technique for lumbar spondylolisthesis provide good patient satisfaction. Good outcome has been reported by only laminectomy alone, but patient satisfaction becomes worse year after year. The role of instrumentation for lumbar spondylolisthesis is decompression of the nerve root, correction of lumbar pathologies, bony fusion and early mobilization. We show our surgical technique and long term outcome of PLIF with PS for lumbar spondylolisthesis. Three hundred and fifty cases of lumbar spondylolisthesis were operated on in Department of Neurosurgery, Fujita Health University during the period of from December 1992 to August 2008. Patient background: age 16-84 years old (mean 62.5), Gender: male 153, female 197. Follow-up period 1-180 months (mean 61.2). Degenerative: 255, Isthmic: 63, Dysplastic: 10, Fracture: 5 and scoliosis 16 cases. Surgical procedure was PS with interbody fusion cage: 331, Hybrid cage (titanium cage with hydroxyapatite) 314, PS with Cerabone: 2 and PS with autograft: 17. CT was done to evaluate bony fusion postoperatively. Post operative improvements by JOA (Japan Orthopedic Association) score is 11.4 before surgery, 24.1 (post op. within 2 years), 25.4 (post op. 2-5 years), 25.0 (post op. 5-10 years) and 22.4 (post op. 10-15 years). Significant improvements were observed in %Slip and Slip angle but no remarkable change was observed in lumbar lordotic angle by postoperative X-ray evaluation. No root injury, and systemic complication except 4 cases of cerebrospinal fluid (CSF) leakage during surgery. Two cases were reoperated in whom cage with autograft migration due to pseudoarthrosis. Two cases had to undergo screw and cage system removal due to infection. Two cases of adjacent level stenosis had to undergo operation 10

  7. Visceral, vascular, and wound complications following over 13,000 lateral interbody fusions: a survey study and literature review.

    Science.gov (United States)

    Uribe, Juan S; Deukmedjian, Armen R

    2015-04-01

    Minimally invasive lateral interbody fusion (MIS-LIF) has become a popular less invasive treatment option for degenerative spinal disease, deformity, and trauma. While MIS-LIF offers several advantages over traditional anterior and posterior approaches, the procedure is not without risk. The purpose of this study was to evaluate the incidence of visceral, vascular, and wound complications following MIS-LIF performed by experienced surgeons. A survey was conducted by experienced (more than 100 case experience) MIS-LIF surgeons active in the society of lateral access surgery (SOLAS) to collect data on wound infections and visceral and vascular injuries. Of 77 spine surgeons surveyed, 40 (52 %) responded, including 25 (63 %) orthopedic surgeons and 15 (38 %) neurosurgeons, with 20 % practicing at an academic institution and 80 % in community practice. Between 2003 and 2013, 13,004 patients were treated with MIS-LIF by the 40 surgeons who responded to the survey. Of those patients, 0.08 % experienced a visceral complication (bowel injury), 0.10 % experienced a vascular injury, 0.27 % experienced a superficial wound infection, and 0.14 % experienced a deep wound infection. The incidence of surgical site infections and vascular and visceral complications following MIS-LIF in this large series was low and compared favorably with rates for alternative interbody fusion approaches. Although technically demanding, MIS-LIF is a reproducible approach for interbody fusion with a low risk of vascular and visceral complications and infections.

  8. Posterior lumbar interbody fusion and posterolateral fusion: Analogous procedures in decreasing the index of disability in patients with spondylolisthesis.

    Science.gov (United States)

    Alijani, Babak; Emamhadi, Mohamahreza; Behzadnia, Hamid; Aramnia, Ali; Chabok, Shahrokh Yousefzadeh; Ramtinfar, Sara; Leili, Ehsan Kazemnejad; Golmohamadi, Shabnam

    2015-01-01

    The purpose of this study was to evaluate the disability in patients with spondylolisthesis who assigned either to posterolateral fusion (PLF) or posterior lumbar interbody fusion (PLIF) and to compare it between two groups. In a prospective observational study, 102 surgical candidates with low-grade degenerative and isthmic spondylolisthesis enrolled from 2012 to 2014, and randomly assigned into two groups: PLF and PLIF. Evaluation of disability has been done by a questionnaire using Oswestry Disability Index (ODI). The questionnaire was completed by all patients before the surgery, the day after surgery, after 6 months and after 1-year. There were no statistically significant differences in terms of age and sex distribution and pre-operation ODI between groups (P > 0.05). Comparison of the mean ODI scores of two groups over the whole study period showed no significant statistical difference (P = 0.074). ODIs also showed no significant differences between two groups the day after surgery, 6(th) months and 1-year after surgery (P = 0.385, P = 0.093, P = 0.122 and P = 433) respectively. Analyzing the course of ODI over the study period, showed a significant descending pattern for either of groups (P disability of patients with spondylolisthesis, and none of the fusion techniques were related to a better outcome in terms of disability.

  9. Stand-alone induction generators for small water power schemes

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, Adam [Intermediate Technology Development Group, Rugby (United Kingdom); Smith, Nigel [Smith Associates, Nottingham (United Kingdom)

    1996-04-01

    Conventional technology for isolated power generation is the synchronous generator. Using stand-alone induction generators has proved to have tremendous advantages in remote regions of developing countries, where electricity has significant social benefits. (author)

  10. Basic Stand Alone Medicare DME Line Items PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Durable Medical Equipment (DME) Line Items Public Use Files (PUF) with information from Medicare DME claims. The...

  11. Basic Stand Alone Skilled Nursing Facility Beneficiary PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Skilled Nursing Facility (SNF) Beneficiary Public Use Files (PUF) with information from Medicare SNF claims. The...

  12. A STUDY OF POSTERIOR LUMBAR INTERBODY FUSION WITH LOCALLY HARVESTED SPINOLAMINECTOMY BONE GRAFT AND PEDICLE SCREW FIXATION IN SPONDYLOLISTHESIS

    Directory of Open Access Journals (Sweden)

    Pardhasaradhi M

    2017-08-01

    Full Text Available BACKGROUND Posterior Lumbar Interbody Fusion (PLIF and Transforaminal Lumbar Interbody Fusion (TLIF create intervertebral fusion by means of a posterior approach. Successful results have been reported with allograft, various cages (for interbody support, autograft and recombinant human bone morphogenetic protein‐2. Interbody fusion techniques facilitate reduction and enhance fusion. Corticocancellous laminectomy bone chips alone can be used as a means of spinal fusion in patients with single level instrumented PLIF. This has got a good fusion rate. PLIF with cage gives better fusion on radiology than PLIF with iliac bone graft, but no statistical difference in the clinical outcome. Cage use precludes complications associated with iliac bone harvesting. The reported adjacent segment degeneration was 40.5% and reoperation was 8.1% after 10 years of follow up. MATERIALS AND METHODS 30 cases of spondylolisthesis who attended the Orthopaedic Outpatient Department of Andhra Medical College, Visakhapatnam, from 2014 to 2016 were taken up for study. All the cases were examined clinically and confirmed radiologically. The patient’s age, sex, symptoms and duration were noted and were examined clinically for the status of the spine. Straight leg raising test was done and neurological examination of the lower limbs performed. All the patients were subjected to the radiological examination of the lumbosacral spine by taking anteroposterior, lateral (flexion and extension views, oblique views to demonstrate spondylolysis and spondylolisthesis. MRI and x-rays studies were done in all the cases to facilitate evaluation of the root compression disk changes and spinal cord changes. RESULTS In our study, we followed all the 30 patients after the surgery following procedure of removal of loose lamina, spinous process and fibrocartilaginous mass, PLIF with only the laminectomy bone mass and CD screw system fixation up to 2 years. 12 patients (40% had excellent

  13. Impaction durability of porous polyether-ether-ketone (PEEK) and titanium-coated PEEK interbody fusion devices.

    Science.gov (United States)

    Torstrick, F Brennan; Klosterhoff, Brett S; Westerlund, L Erik; Foley, Kevin T; Gochuico, Joanna; Lee, Christopher S D; Gall, Ken; Safranski, David L

    2018-05-01

    Various surface modifications, often incorporating roughened or porous surfaces, have recently been introduced to enhance osseointegration of interbody fusion devices. However, these topographical features can be vulnerable to damage during clinical impaction. Despite the potential negative impact of surface damage on clinical outcomes, current testing standards do not replicate clinically relevant impaction loading conditions. The purpose of this study was to compare the impaction durability of conventional smooth polyether-ether-ketone (PEEK) cervical interbody fusion devices with two surface-modified PEEK devices that feature either a porous structure or plasma-sprayed titanium coating. A recently developed biomechanical test method was adapted to simulate clinically relevant impaction loading conditions during cervical interbody fusion procedures. Three cervical interbody fusion devices were used in this study: smooth PEEK, plasma-sprayed titanium-coated PEEK, and porous PEEK (n=6). Following Kienle et al., devices were impacted between two polyurethane blocks mimicking vertebral bodies under a constant 200 N preload. The posterior tip of the device was placed at the entrance between the polyurethane blocks, and a guided 1-lb weight was impacted upon the anterior face with a maximum speed of 2.6 m/s to represent the strike force of a surgical mallet. Impacts were repeated until the device was fully impacted. Porous PEEK durability was assessed using micro-computed tomography (µCT) pre- and postimpaction. Titanium-coating coverage pre- and postimpaction was assessed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy. Changes to the surface roughness of smooth and titanium-coated devices were also evaluated. Porous PEEK and smooth PEEK devices showed minimal macroscopic signs of surface damage, whereas the titanium-coated devices exhibited substantial visible coating loss. Quantification of the porous PEEK deformation

  14. Minimally invasive presacral approach for revision of an Axial Lumbar Interbody Fusion rod due to fall-related lumbosacral instability: a case report

    Directory of Open Access Journals (Sweden)

    Cohen Anders

    2011-09-01

    Full Text Available Abstract Introduction The purpose of this study was to describe procedural details of a minimally invasive presacral approach for revision of an L5-S1 Axial Lumbar Interbody Fusion rod. Case presentation A 70-year-old Caucasian man presented to our facility with marked thoracolumbar scoliosis, osteoarthritic changes characterized by high-grade osteophytes, and significant intervertebral disc collapse and calcification. Our patient required crutches during ambulation and reported intractable axial and radicular pain. Multi-level reconstruction of L1-4 was accomplished with extreme lateral interbody fusion, although focal lumbosacral symptoms persisted due to disc space collapse at L5-S1. Lumbosacral interbody distraction and stabilization was achieved four weeks later with the Axial Lumbar Interbody Fusion System (TranS1 Inc., Wilmington, NC, USA and rod implantation via an axial presacral approach. Despite symptom resolution following this procedure, our patient suffered a fall six weeks postoperatively with direct sacral impaction resulting in symptom recurrence and loss of L5-S1 distraction. Following seven months of unsuccessful conservative care, a revision of the Axial Lumbar Interbody Fusion rod was performed that utilized the same presacral approach and used a larger diameter implant. Minimal adhesions were encountered upon presacral re-entry. A precise operative trajectory to the base of the previously implanted rod was achieved using fluoroscopic guidance. Surgical removal of the implant was successful with minimal bone resection required. A larger diameter Axial Lumbar Interbody Fusion rod was then implanted and joint distraction was re-established. The radicular symptoms resolved following revision surgery and our patient was ambulating without assistance on post-operative day one. No adverse events were reported. Conclusions The Axial Lumbar Interbody Fusion distraction rod may be revised and replaced with a larger diameter rod using

  15. Posterior lumbar interbody fusion using nonresorbable poly-ether-ether-ketone versus resorbable poly-L-lactide-co-D,L-lactide fusion devices: a prospective, randomized study to assess fusion and clinical outcome

    NARCIS (Netherlands)

    Jiya, T.U.; Smit, T.H.; Deddens, J.; Mullender, M.G.

    2009-01-01

    STUDY DESIGN: A prospective randomized clinical study. OBJECTIVE.: To assess fusion, clinical outcome, and complications. SUMMARY OF BACKGROUND DATA: Resorbable poly-L- lactide-co-D,L-lactide (PLDLLA) cages intended to aid spinal interbody fusion have been introduced into clinical practice within

  16. Extraforaminal Lumbar Interbody Fusion at the L5-S1 Level: Technical Considerations and Feasibility.

    Science.gov (United States)

    Kurzbuch, Arthur Robert; Kaech, Denis; Baranowski, Pawel; Baranowska, Alicja; Recoules-Arche, Didier

    2017-09-01

    Background  Extraforaminal lumbar interbody fusion (ELIF) surgery is a muscle-sparing approach that allows the treatment of various degenerative spinal diseases. It is technical challenging to perform the ELIF approach at the L5-S1 level because the sacral ala obstructs the view of the intervertebral disk space. Methods  We reported earlier on the ELIF technique in which the intervertebral disk is targeted at an angle of 45 degrees relative to the midline. In this article we describe the technical process we developed to overcome the anatomic relation between the sacral ala and the intervertebral disk space L5-S1 that hinders the ELIF approach at this level. We then report in a retrospective analysis on the short-term clinical and radiologic outcome of 100 consecutive patients with degenerative L5-S1 pathologies who underwent ELIF surgery. Results  The L5-S1 ELIF approach could be realized in all patients. The short-term clinical outcome was evaluated 5 months after surgery: 92% of the patients were satisfied with their postoperative result; 8% had a poor result. Overall, 17% of the patients presented light radicular or low back pain not influencing their daily activity, and 82% of the patients working before surgery returned to work 3 to 7 months after surgery. The radiologic outcome was documented by computed tomography at 5 months after surgery and showed fusion in 99% of the patients. Lumbar magnetic resonance imaging performed in 5 patients at 6 months after surgery revealed the integrity of the paraspinal muscles. Conclusions  ELIF surgery at the L5-S1 level is technically feasible for various degenerative spinal diseases. Analysis of the clinical and radiologic data in a consecutive retrospective cohort of patients who underwent this surgical procedure showed a good short-term clinical outcome and fusion rate. Georg Thieme Verlag KG Stuttgart · New York.

  17. Characterization of a novel caudal vertebral interbody fusion in a rat tail model: An implication for future material and mechanical testing

    Directory of Open Access Journals (Sweden)

    Yu-Cheng Yeh

    2017-02-01

    Conclusion: The rat caudal disc interbody fusion model proved to be an efficient, repeatable and easily accessible model. Future research into adjuvant treatments like growth factor injection and alternative fusion materials under conditions of osteoporosis using this model would be worthwhile.

  18. Does prone repositioning before posterior fixation produce greater lordosis in lateral lumbar interbody fusion (LLIF)?

    Science.gov (United States)

    Yson, Sharon C; Sembrano, Jonathan N; Santos, Edward R G; Luna, Jeffrey T P; Polly, David W

    2014-10-01

    Retrospective comparative radiographic review. To determine if lateral to prone repositioning before posterior fixation confers additional operative level lordosis in lateral lumbar interbody fusion (LLIF) procedures. In a review of 56 consecutive patients who underwent LLIF, there was no statistically significant change in segmental lordosis from lateral to prone once a cage is in place. The greatest lordosis increase was observed after cage insertion. We reviewed 56 consecutive patients who underwent LLIF in the lateral position followed by posterior fixation in the prone position. Eighty-eight levels were fused. Disk space angle was measured on intraoperative C-arm images, and change in operative level segmental lordosis brought about by each of the following was determined: (1) cage insertion, (2) prone repositioning, and (3) posterior instrumentation. Paired t test was used to determine significance (α=0.05). Mean lordosis improvement brought about by cage insertion was 2.6 degrees (P=0.00005). There was a 0.1 degree mean lordosis change brought about by lateral to prone positioning (P=0.47). Mean lordosis improvement brought about by posterior fixation, including rod compression, was 1.0 degree (P=0.03). In LLIF procedures, the largest increase in operative level segmental lordosis is brought about by cage insertion. Further lordosis may be gained by placing posterior fixation, including compressive maneuvers. Prone repositioning after cage placement does not produce any incremental lordosis change. Therefore, posterior fixation may be performed in the lateral position without compromising operative level sagittal alignment.

  19. Clinical outcomes of two minimally invasive transforaminal lumbar interbody fusion (TLIF) for lumbar degenerative diseases.

    Science.gov (United States)

    Tian, Yonghao; Liu, Xinyu

    2016-10-01

    There are two modified TLIF, including MIS-TLIF and TLIF through Wiltse approach (W-TLIF). Although both of the two minimally invasive surgical procedures can be effective in the treatment for lumbar degenerative diseases, no comparative analysis has been made so far regarding their clinical outcomes. To compare the clinical outcomes of MIS-TLIF and W-TLIF for the treatment for single-segment degenerative lumbar diseases. Ninety-seven patients with single-segment degenerative lumbar disorders were included in this study. Forty-seven underwent MIS-TLIF surgery (group A). For group B, fifty patients underwent W-TLIF. The Japanese Orthopedic Association (JOA) score, the visual analog scale (VAS) of low back pain (LBP) and leg pain, MRI score and atrophy rate of CSA, interbody fusion rate were assessed during the postoperative follow-up. Incision length, blood loss, operative time, CPK, and postoperative incision pain VAS were better in group A (P degenerative disease. MIS-TLIF has less blood loss, shorter surgical incision, and less lower postoperative back pain, while W-TLIF is less expensive for hospital stay with lower exposure to X-rays.

  20. Accidental Durotomy in Minimally Invasive Transforaminal Lumbar Interbody Fusion: Frequency, Risk Factors, and Management

    Directory of Open Access Journals (Sweden)

    Jan-Helge Klingler

    2015-01-01

    Full Text Available Purpose. To assess the frequency, risk factors, and management of accidental durotomy in minimally invasive transforaminal lumbar interbody fusion (MIS TLIF. Methods. This single-center study retrospectively investigates 372 patients who underwent MIS TLIF and were mobilized within 24 hours after surgery. The frequency of accidental durotomies, intraoperative closure technique, body mass index, and history of previous surgery was recorded. Results. We identified 32 accidental durotomies in 514 MIS TLIF levels (6.2%. Analysis showed a statistically significant relation of accidental durotomies to overweight patients (body mass index ≥25 kg/m2; P=0.0493. Patient age older than 65 years tended to be a positive predictor for accidental durotomies (P=0.0657. Mobilizing patients on the first postoperative day, we observed no durotomy-associated complications. Conclusions. The frequency of accidental durotomies in MIS TLIF is low, with overweight being a risk factor for accidental durotomies. The minimally invasive approach seems to minimize durotomy-associated complications (CSF leakage, pseudomeningocele because of the limited dead space in the soft tissue. Patients with accidental durotomy can usually be mobilized within 24 hours after MIS TLIF without increased risk. The minimally invasive TLIF technique might thus be beneficial in the prevention of postoperative immobilization-associated complications such as venous thromboembolism. This trial is registered with DRKS00006135.

  1. The expandable transforaminal lumbar interbody fusion – Two years follow-up

    Directory of Open Access Journals (Sweden)

    Joseph Gamal Boktor

    2018-01-01

    Conclusions: These preliminary results indicate that the use of an expandable interbody cage achieves good clinical outcomes by improving and maintaining foraminal dimensions and disc height with minimal complication rate.

  2. Evaluation of a novel tool for bone graft delivery in minimally invasive transforaminal lumbar interbody fusion

    Directory of Open Access Journals (Sweden)

    Kleiner JB

    2016-05-01

    Full Text Available Jeffrey B Kleiner, Hannah M Kleiner, E John Grimberg Jr, Stefanie J Throlson The Spine Center of Innovation, The Medical Center of Aurora, Aurora, CO, USA Study design: Disk material removed (DMR during L4-5 and L5-S1 transforaminal lumbar interbody fusion (T-LIF surgery was compared to the corresponding bone graft (BG volumes inserted at the time of fusion. A novel BG delivery tool (BGDT was used to apply the BG. In order to establish the percentage of DMR during T-LIF, it was compared to DMR during anterior diskectomy (AD. This study was performed prospectively. Summary of background data: Minimal information is available as to the volume of DMR during a T-LIF procedure, and the relationship between DMR and BG delivered is unknown. BG insertion has been empiric and technically challenging. Since the volume of BG applied to the prepared disk space likely impacts the probability of arthrodesis, an investigation is justified. Methods: A total of 65 patients with pathology at L4-5 and/or L5-S1 necessitating fusion were treated with a minimally invasive T-LIF procedure. DMR was volumetrically measured during disk space preparation. BG material consisting of local autograft, BG extender, and bone marrow aspirate were mixed to form a slurry. BG slurry was injected into the disk space using a novel BGDT and measured volumetrically. An additional 29 patients who were treated with L5-S1 AD were compared to L5-S1 T-LIF DMR to determine the percent of T-LIF DMR relative to AD. Results: DMR volumes averaged 3.6±2.2 mL. This represented 34% of the disk space relative to AD. The amount of BG delivered to the disk spaces was 9.3±3.2 mL, which is 2.6±2.2 times the amount of DMR. The BGDT allowed uncomplicated filling of the disk space in <1 minute. Conclusion: The volume of DMR during T-LIF allows for a predictable volume of BG delivery. The BGDT allowed complete filling of the entire prepared disk space. The T-LIF diskectomy debrides 34% of the disk

  3. Two-year Outcomes from a Single Surgeon's Learning Curve Experience of Oblique Lateral Interbody Fusion without Intraoperative Neuromonitoring.

    Science.gov (United States)

    Woods, Kamal; Fonseca, Ahtziri; Miller, Larry E

    2017-12-22

    Introduction Oblique lumbar interbody fusion (OLIF) is a newer procedure that avoids the psoas and lumbosacral plexus due to its oblique trajectory into the retroperitoneal space. While early experience with OLIF is reassuring, the longer-term clinical efficacy has not been well established. The purpose of this study was to describe two-year clinical outcomes with OLIF performed by a single surgeon during the learning curve without the aid of the neuromonitoring. Materials and methods Chart review was performed for the consecutive patients who underwent OLIF by a single surgeon. Back pain severity on a visual analog scale (VAS) and Oswestry Disability Index (ODI) were collected preoperatively and postoperatively at six weeks, three months, six months, one year and two years. Results A total of 21 patients (38 levels) were included in this study. The indications for surgery were degenerative disc disease (n=10, 47.6%), spondylolisthesis (n=9, 42.9%) and spinal stenosis (n=6, 28.6%). The median operating room time was 351 minutes (interquartile range (IQR): 279-406 minutes), blood loss was 40 ml (IQR: 30-150 ml), and hospital stay was 2.0 days (IQR: 1.0-3.5 days). The complication rate was 9.5%, both venous injuries. There were no other perioperative complications. Back pain severity decreased by 70%, on average, over two years (p safe and clinically efficacious for up to two years. The complication rate in this cohort is similar to other published OLIF series and appears acceptable when compared to the lateral lumbar interbody fusion (LLIF) and the anterior lumbar interbody fusion (ALIF). No motor or sensory deficits were observed in this study, supporting the premise that the neuromonitoring is unnecessary in OLIF.

  4. Preliminary Experience with Anterior Interbody Titanium Cage Fusion for Treatment of Cervical Disc Disease

    Directory of Open Access Journals (Sweden)

    Chung-Nan Lin

    2003-05-01

    Full Text Available This study evaluated the efficacy and safety of titanium cage implants in cervical reconstruction to treat cervical spondylosis. Surgical data covered a 4-year period from January 1999 to December 2002 and included 34 consecutive patients, 20 men and 14 women, with ages ranging from 27 to 84 years (mean, 57 years. Patients underwent anterior cervical microdiscectomy followed by interbody fusion with a titanium cage implant (rather than an autogenous iliac crest bone graft at a single level ranging from C3 to C7. Twenty-one patients had a herniated intervertebral disc, nine had degenerative disc disease, and four had previous failed autograft fusion surgery that required revision. At clinical presentation, 26 patients had neck pain, 23 had radiculopathy, and nine had myelopathy. Diagnostic imaging studies included spinal dynamic roentgenography, computerized tomography, and magnetic resonance imaging. Lesions were located at C3-4 in seven cases, C4-5 in 14 cases, C5-6 in nine cases, and C6-7 in four cases. The follow-up period ranged from 7 to 48 months (mean, 26 months. Results revealed that the procedure was technically feasible. There were no intra- or postoperative complications. The most commonly used cage was 9 mm high. Imaging studies showed no cage instability, migration, or pseudarthrosis. Although mild subsidence (< 5 mm was observed in three cases, these patients preserved adequate postoperative cervical lordosis and the subsidence did not preclude a good clinical result. The advantages of this procedure over a similar operation using traditional tricorticate bone graft are: no graft morbidity; shorter operation time (mean time saved, 35 minutes; reduced blood loss (average blood loss, 75 mL; and early postoperative ambulation (mean, 4.7 hospital days. Nearly all patients rapidly lost their neck pain (92%, 24/26 and radicular symptoms (87%, 20/23 after surgery. The recovery rate from myelopathy was 44% (4/9. Progressive bony shield

  5. Mast Quadrant-assisted Minimally Invasive Modified Transforaminal Lumbar Interbody Fusion: Single Incision Versus Double Incision

    Directory of Open Access Journals (Sweden)

    Xin-Lei Xia

    2015-01-01

    Full Text Available Background: The concept of minimally invasive techniques is to make every effort to reduce tissue damage. Certainly, reducing skin incision is an important part of these techniques. This study aimed to investigate the clinical feasibility of Mast Quadrant-assisted modified transforaminal lumbar interbody fusion (TLIF with a small single posterior median incision. Methods: During the period of March 2011 to March 2012, 34 patients with single-segment degenerative lumbar disease underwent the minimally invasive modified TLIF assisted by Mast Quadrant with a small single posterior median incision (single incision group. The cases in this group were compared to 37 patients with single-segment degenerative lumbar disease in the double incision group. The perioperative conditions of patients in these two groups were statistically analyzed and compared. The Oswestry Disability Index (ODI scores, Visual Analog Scale (VAS scores, and sacrospinalis muscle damage evaluation indicators before operation and 3, 12 months postoperation were compared. Results: A total of 31 and 35 cases in the single incision and double incision groups, respectively, completed at least 12 months of systemic follow-up. The differences in perioperative conditions between the two groups were not statistically significant. The incision length of the single incision group was significantly shorter than that of the double incision group (P < 0.01. The ODI and VAS scores of patients in both groups improved significantly at 3 and 12 months postoperation. However, these two indicators at 3 and 12 months postoperation and the sacrospinalis muscle damage evaluation indicators at 3 months postoperation did not differ significantly between the two groups (P ≥ 0.05. Conclusions: Mast Quadrant-assisted modified TLIF with a small single posterior median incision has excellent clinical feasibility compared to minimally invasive TLIF with a double paramedian incision.

  6. The stand-alone test and decreasing serial cost sharing

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Thorlund-Petersen, Lars

    2000-01-01

    The rule of decreasing serial cost sharing defined in de Frutos [1] over the class of concave cost functions may violate the important stand-alone test. Sufficient conditions for the test to be satisfied are given, in terms of individual rationality as well as coalitional stability...

  7. Stand-alone solutions, computer networks and extern communications

    International Nuclear Information System (INIS)

    Tarschisch, H.

    1988-01-01

    The advantages of local networks over stand-alone solutions are presented. Of the local networks (LAN), two are presently at the center of attention: the bus and the ring. ETHERNET and the IBM-Token-Ring are described as typical examples. Access to public networks, especially TELEPAC and ISDN, is discussed. 12 figs

  8. Ampere hour method of sizing a stand alone photovoltaic system ...

    African Journals Online (AJOL)

    Stand-alone photovoltaic power systems are natural options for application in electrification of remote areas which are not served by the grid electricity supply system. An ampere-hour ... Sizing of the balance-of-system were carefully handled to avoid undersizing or oversizing and subsequent variation in supply reliability.

  9. Effects of Addition of Preoperative Intravenous Ibuprofen to Pregabalin on Postoperative Pain in Posterior Lumbar Interbody Fusion Surgery

    Directory of Open Access Journals (Sweden)

    Hüseyin Ulaş Pınar

    2017-01-01

    Full Text Available Objective. Ibuprofen and pregabalin both have independent positive effects on postoperative pain. The aim of the study is researching effect of 800 mg i.v. ibuprofen in addition to preoperative single dose pregabalin on postoperative analgesia and morphine consumption in posterior lumbar interbody fusion surgery. Materials and Methods. 42 adult ASA I-II physical status patients received 150 mg oral pregabalin 1 hour before surgery. Patients received either 250 ml saline with 800 mg i.v. ibuprofen or saline without ibuprofen 30 minutes prior to the surgery. Postoperative analgesia was obtained by morphine patient controlled analgesia (PCA and 1 g i.v. paracetamol every six hours. PCA morphine consumption was recorded and postoperative pain was evaluated by Visual Analog Scale (VAS in postoperative recovery room, at the 1st, 2nd, 4th, 8th, 12th, 24th, 36th, and 48th hours. Results. Postoperative pain was significantly lower in ibuprofen group in recovery room, at the 1st, 2nd, 36th, and 48th hours. Total morphine consumption was lower in ibuprofen group at the 2nd, 4th, 8th, 12th, and 48th hours. Conclusions. Multimodal analgesia with preoperative ibuprofen added to preoperative pregabalin safely decreases postoperative pain and total morphine consumption in patients having posterior lumbar interbody fusion surgery, without increasing incidences of bleeding or other side effects.

  10. The effect of anterior longitudinal ligament resection on lordosis correction during minimally invasive lateral lumbar interbody fusion: Biomechanical and radiographic feasibility of an integrated spacer/plate interbody reconstruction device.

    Science.gov (United States)

    Kim, Choll; Harris, Jonathan A; Muzumdar, Aditya; Khalil, Saif; Sclafani, Joseph A; Raiszadeh, Kamshad; Bucklen, Brandon S

    2017-03-01

    Lateral lumbar interbody fusion is powerful for correcting degenerative conditions, yet sagittal correction remains limited by anterior longitudinal ligament tethering. Although lordosis has been restored via ligament release, biomechanical consequences remain unknown. Investigators examined radiographic and biomechanical of ligament release for restoration of lumbar lordosis. Six fresh-frozen human cadaveric spines (L3-S1) were tested: (Miller et al., 1988) intact; (Battie et al., 1995) 8mm spacer with intact anterior longitudinal ligament; (Cho et al., 2013) 8mm spacer without intact ligament following ligament resection; (Galbusera et al., 2013) 13mm lateral lumbar interbody fusion; (Goldstein et al., 2001) integrated 13mm spacer. Focal lordosis and range of motion were assessed by applying pure moments in flexion-extension, lateral bending, and axial rotation. Cadaveric radiographs showed significant improvement in lordosis correction following ligament resection (P0.05) but did little to restore lordosis. Ligament release significantly destabilized the spine relative to intact in all modes and 8mm with ligament in lateral bending and axial rotation (P0.05). Lordosis corrected by lateral lumbar interbody fusion can be improved by anterior longitudinal ligament resection, but significant construct instability and potential implant migration/dislodgment may result. This study shows that an added integrated lateral fixation system can significantly improve construct stability. Long-term multicenter studies are needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Models for a stand-alone PV system

    DEFF Research Database (Denmark)

    Hansen, A.D.; Sørensen, Poul Ejnar; Hansen, L.H.

    2001-01-01

    are based on the model descriptions found in the literature. The battery model is developed at UMASS and is known as the Kinetic Battery Model(KiBaM). The other component models in the PV system are based on simple electrical knowledge. The implementation is done using Matlab/Simulink, a simulation program......This report presents a number of models for modelling and simulation of a stand-alone photovoltaic (PV) system with a battery bank verified against a system installed at Risø National Laboratory. The work has been supported by the Danish Ministry ofEnergy, as a part of the activities in the Solar...... Energy Centre Denmark. The study is carried out at Risø National Laboratory with the main purpose to establish a library of simple mathematical models for each individual element of a stand-alone PVsystem, namely solar cells, battery, controller, inverter and load. The models for PV module and battery...

  12. Optimal sizing method for stand-alone photovoltaic power systems

    Energy Technology Data Exchange (ETDEWEB)

    Groumpos, P P; Papageorgiou, G

    1987-01-01

    The total life-cycle cost of stand-alone photovoltaic (SAPV) power systems is mathematically formulated. A new optimal sizing algorithm for the solar array and battery capacity is developed. The optimum value of a balancing parameter, M, for the optimal sizing of SAPV system components is derived. The proposed optimal sizing algorithm is used in an illustrative example, where a more economical life-cycle cost has bene obtained. The question of cost versus reliability is briefly discussed.

  13. Posterior lumbar interbody fusion (PLIF) with cages and local bone graft in the treatment of spinal stenosis.

    Science.gov (United States)

    Trouillier, Hans; Birkenmaier, Christof; Rauch, Alexander; Weiler, Christoph; Kauschke, Thomas; Refior, Hans Jürgen

    2006-08-01

    Posterior lumbar interbody fusion (PLIF) implants are increasingly being used for 360 degrees fusion after decompression of lumbar spinal stenosis combined with degenerative instability. Both titanium and PEEK (PolyEtherEtherKetone) implants are commonly used. Assessing the clinical and radiological results as well as typical complications, such as migration of the cages, is important. In addition, questions such as which radiological parameters can be used to assess successful fusion, and whether the exclusive use of local bone graft is sufficient, are frequently debated. We prospectively evaluated 30 patients after PLIF instrumentation for degenerative lumbar spinal canal stenosis, over a course of 42 months. In all cases, titanium cages and local bone graft were used for spondylodesis. The follow-up protocol of these 30 cases included standardised clinical and radiological evaluation at 3, 6, 12 and 42 months after surgery. Overall satisfactory results were achieved. With one exception, a stable result was achieved with restoration of the intervertebral space in the anterior column. After 42 months of follow-up in most cases, a radiologically visible loss of disc space height can be demonstrated. Clinically relevant migration of the cage in the dorsal direction was detected in one case. Based on our experience, posterior lumbar interbody fusion (PLIF) can be recommended for the treatment of monosegmental and bisegmental spinal stenosis, with or without segmental instability. Postoperative evaluation is mainly based on clinical parameters since the titanium implant affects the diagnostic value of imaging studies and is responsible for artefacts. The results observed in our group of patients suggest that local autologous bone graft procured from the posterior elements after decompression is an adequate material for bone grafting in this procedure.

  14. Do intraoperative radiographs predict final lumbar sagittal alignment following single-level transforaminal lumbar interbody fusion?

    Science.gov (United States)

    Salem, Khalid M I; Eranki, Aditya P; Paquette, Scott; Boyd, Michael; Street, John; Kwon, Brian K; Fisher, Charles G; Dvorak, Marcel F

    2018-05-01

    OBJECTIVE The study aimed to determine if the intraoperative segmental lordosis (as calculated on a cross-table lateral radiograph following a single-level transforaminal lumbar interbody fusion [TLIF] for degenerative spondylolisthesis/low-grade isthmic spondylolisthesis) is maintained at discharge and at 6 months postsurgery. METHODS The authors reviewed images and medical records of patients ≥ 16 years of age with a diagnosis of an isolated single-level, low-grade spondylolisthesis (degenerative or isthmic) with symptomatic spinal stenosis treated between January 2008 and April 2014. Age, sex, surgical level, surgical approach, and facetectomy (unilateral vs bilateral) were recorded. Upright standardized preoperative, early, and 6-month postoperative radiographs, as well as intraoperative lateral radiographs, were analyzed for the pelvic incidence, segmental lumbar lordosis (SLL) at the TILF level, and total LL (TLL). In addition, the anteroposterior position of the cage in the disc space was documented. Data are presented as the mean ± SD; a p value level using a bullet-shaped cage. A bilateral facetectomy was performed in 17 patients (20.2%), and 89.3% of procedures were done at the L4-5 and L5-S1 segments. SLL significantly improved intraoperatively from 15.8° ± 7.5° to 20.9° ± 7.7°, but the correction was lost after ambulation. Compared with preoperative values, at 6 months the change in SLL was modest at 1.8° ± 6.7° (p = 0.025), whereas TLL increased by 4.3° ± 9.6° (p level of surgery, and use of a bilateral facetectomy did not significantly affect postoperative LL. CONCLUSIONS Following a single-level TLIF procedure using a bullet-shaped cage, the intraoperative improvement in SLL is largely lost after ambulation. The improvement in TLL over time is probably due to the decompression part of the procedure. The approach, level of surgery, bilateral facetectomy, and position of the cage do not seem to have a significant effect on LL achieved

  15. Comparison of serum markers for muscle damage, surgical blood loss, postoperative recovery, and surgical site pain after extreme lateral interbody fusion with percutaneous pedicle screws or traditional open posterior lumbar interbody fusion.

    Science.gov (United States)

    Ohba, Tetsuro; Ebata, Shigeto; Haro, Hirotaka

    2017-10-16

    The benefits of extreme lateral interbody fusion (XLIF) as a minimally invasive lumbar spinal fusion treatment for lumbar degenerative spondylolisthesis have been unclear. We sought to evaluate the invasiveness and tolerability of XLIF with percutaneous pedicle screws (PPS) compared with traditional open posterior lumbar interbody fusion (PLIF). Fifty-six consecutive patients underwent open PLIF and 46 consecutive patients underwent single-staged treatment with XLIF with posterior PPS fixation for degenerative lumbar spondylolisthesis, and were followed up for a minimum of 1 year. We analyzed postoperative serum makers for muscle damage and inflammation, postoperative surgical pain, and performance status. A Roland-Morris Disability Questionnaire (RDQ) and Oswestry Disability Index (ODI) were obtained at the time of hospital admission and 1 year after surgery. Intraoperative blood loss (51 ± 41 ml in the XLIF/PPS group and 206 ± 191 ml in the PLIF group), postoperative WBC counts and serum CRP levels in the XLIF/PPS group were significantly lower than in the PLIF group. Postoperative serum CK levels were significantly lower in the XLIF/PPS group on postoperative days 4 and 7. Postoperative recovery of performance was significantly greater in the XLIF/PPS group than in the PLIF group from postoperative days 2 to 7. ODI and visual analog scale (VAS) score (lumbar) 1 year after surgery were significantly lower in the XLIF/PPS group compared with the PLIF group. The XLIF/PPS procedure is advantageous to minimize blood loss and muscle damage, with consequent earlier recovery of daily activities and reduced incidence of low back pain after surgery than with the open PLIF procedure.

  16. MIS Single-position Lateral and Oblique Lateral Lumbar Interbody Fusion and Bilateral Pedicle Screw Fixation: Feasibility and Perioperative Results.

    Science.gov (United States)

    Blizzard, Daniel J; Thomas, J Alex

    2018-03-15

    Retrospective review of prospectively collected data of the first 72 consecutive patients treated with single-position one- or two-level lateral (LLIF) or oblique lateral interbody fusion (OLLIF) with bilateral percutaneous pedicle screw and rod fixation by a single spine surgeon. To evaluate the clinical feasibility, accuracy, and efficiency of a single-position technique for LLIF and OLLIF with bilateral pedicle screw and rod fixation. Minimally-invasive lateral interbody approaches are performed in the lateral decubitus position. Subsequent repositioning prone for bilateral pedicle screw and rod fixation requires significant time and resources and does not facilitate increased lumbar lordosis. The first 72 consecutive patients (300 screws) treated with single-position LLIF or OLLIF and bilateral pedicle screws by a single surgeon between December 2013 and August 2016 were included in the study. Screw accuracy and fusion were graded using computed tomography and several timing parameters were recorded including retractor, fluoroscopy, and screw placement time. Complications including reoperation, infection, and postoperative radicular pain and weakness were recorded. Average screw placement time was 5.9 min/screw (standard deviation, SD: 1.5 min; range: 3-9.5 min). Average total operative time (interbody cage and pedicle screw placement) was 87.9 minutes (SD: 25.1 min; range: 49-195 min). Average fluoroscopy time was 15.0 s/screw (SD: 4.7 s; range: 6-25 s). The pedicle screw breach rate was 5.1% with 10/13 breaches measured as < 2 mm in magnitude. Fusion rate at 6-months postoperative was 87.5%. Two (2.8%) patients underwent reoperation for malpositioned pedicle screws with subsequent resolution of symptoms. The single-position, all-lateral technique was found to be feasible with accuracy, fluoroscopy usage, and complication rates comparable with the published literature. This technique eliminates the time and staffing associated with

  17. Models for a stand-alone PV system[Photovoltaic

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.D.; Soerensen, P.; Hansen, L.H.; Bindner, H.

    2000-12-01

    This report presents a number of models for modelling and simulation of a stand-alone photovoltaic (PV) system with a battery bank verified against a system installed at Risoe National Laboratory. The work has been supported by the Danish Ministry of Energy, as a part of the activities in the Solar Energy Centre Denmark. The study is carried out at Risoe National Laboratory with the main purpose to establish a library of simple mathematical models for each individual element of a stand-alone PV system, namely solar cells, battery, controller, inverter and load. The models for PV module and battery are based on the model descriptions found in the literature. The battery model is developed at UMASS and is known as the Kinetic Battery Model (KiBaM). The other component models in the PV system are based on simple electrical knowledge. The implementation is done using Matlab/Simulink, a simulation program that provides a graphical interface for building models as modular block diagrams. The non-linear behaviour of the battery, observed in the measurements, is investigated and compared to the KiBaM model's performance. A set of linear Black box models are estimated based on the battery measurements. The performance of the best linear Black box model is compared to the KiBaM model. A validation of each of the implemented mathematical model is performed by an interactive analysis and comparison between simulation results and measurements, acquired from the stand-alone PV system at Risoe. (au)

  18. Size-Prediction Analysis for Stand-Alone Photovoltaic System

    International Nuclear Information System (INIS)

    Erusiafe, N. E.; Chendo, M. A. C.

    2002-01-01

    The cost - effectiveness of photovoltaic (PV) generator depends, among others, on its ability to satisfy energy demand and the cost of achieving this. In this work a step - by - step procedure for predicting the size of the main components of a stand - alone PV system (array and storage) is presented. The results yield an expression which can he used lo determine the size of both components at optimum cost and desired reliability. The result from this work compare favourably with some earlier works in that, the system sizes shows some degree of agreement

  19. Availability model of stand-alone photovoltaic system

    Science.gov (United States)

    Mazurek, G.

    2017-08-01

    In this paper we present a simple, empirical model of stand-alone photovoltaic power system availability. The model is a final result of five-year long studies and ground measurements of solar irradiation carried out in Central Europe. The obtained results facilitate sizing of PV modules that have to be installed with taking into account system's availability level in each month of a year. The model can be extended to different geographical locations, with help of local meteorological data or solar irradiation datasets derived from satellite measurements.

  20. Future UK markets for stand-alone renewable energy systems

    International Nuclear Information System (INIS)

    Paish, O.

    1999-01-01

    A study to identify and quantify the market for stand-alone renewable energy supplies of power (photovoltaics, wind and micro-hydro electricity systems) was described. The study focused on small systems, generally less than a few kW installed capacity. It was suggested that in the UK, the emphasis on grid-connected renewable energy technologies (RETs) has blurred the fact that it is 'off-grid' renewable systems that can offer more immediate real commercial markets for the renewables business. With the likelihood of a significant increase in demand for renewables world wide over the next ten years, the UK needs to make a special effort to become involved

  1. Benchmarking the Collocation Stand-Alone Library and Toolkit (CSALT)

    Science.gov (United States)

    Hughes, Steven; Knittel, Jeremy; Shoan, Wendy; Kim, Youngkwang; Conway, Claire; Conway, Darrel J.

    2017-01-01

    This paper describes the processes and results of Verification and Validation (VV) efforts for the Collocation Stand Alone Library and Toolkit (CSALT). We describe the test program and environments, the tools used for independent test data, and comparison results. The VV effort employs classical problems with known analytic solutions, solutions from other available software tools, and comparisons to benchmarking data available in the public literature. Presenting all test results are beyond the scope of a single paper. Here we present high-level test results for a broad range of problems, and detailed comparisons for selected problems.

  2. Enhanced current and voltage regulators for stand-alone applications

    DEFF Research Database (Denmark)

    Federico, de Bosio; Pastorelli, Michele; Antonio DeSouza Ribeiro, Luiz

    2016-01-01

    State feedback decoupling permits to achieve a better dynamic response for Voltage Source in stand-alone applications. The design of current and voltage regulators is performed in the discrete-time domain since it provides better accuracy and allows direct pole placement. As the attainable...... bandwidth of the current loop is mainly limited by computational and PWM delays, a lead compensator structure is proposed to overcome this limitation. The design of the voltage regulator is based on the Nyquist criterion, verifying to guarantee a high sensitivity peak. Discrete-time domain implementation...

  3. Overpowering posterior lumbar instrumentation and fusion with hyperlordotic anterior lumbar interbody cages followed by posterior revision: a preliminary feasibility study.

    Science.gov (United States)

    Kadam, Abhijeet; Wigner, Nathan; Saville, Philip; Arlet, Vincent

    2017-12-01

    OBJECTIVE The authors' aim in this study was to evaluate whether sagittal plane correction can be obtained from the front by overpowering previous posterior instrumentation and/or fusion with hyperlordotic anterior lumbar interbody fusion (ALIF) cages in patients undergoing revision surgery for degenerative spinal conditions and/or spinal deformities. METHODS The authors report their experience with the application of hyperlordotic cages at 36 lumbar levels for ALIFs in a series of 20 patients who underwent revision spinal surgery at a single institution. Included patients underwent staged front-back procedures: ALIFs with hyperlordotic cages (12°, 20°, and 30°) followed by removal of posterior instrumentation and reinstrumentation from the back. Patients were divided into the following 2 groups depending on the extent of posterior instrumentation and fusion during the second stage: long constructs (≥ 6 levels with extension into thoracic spine and/or pelvis) and short constructs (lumbar lordosis increased from 44.3° to 59.8° (p lumbar levels that have pseudarthrosis from the previous posterior spinal fusion. Meticulous selection of levels for ALIF is crucial for safely and effectively performing this technique.

  4. Spondylectomy and lateral lumbar interbody fusion for thoracolumbar kyphosis in an adult with achondroplasia: A case report.

    Science.gov (United States)

    Miyazaki, Masashi; Kanezaki, Shozo; Notani, Naoki; Ishihara, Toshinobu; Tsumura, Hiroshi

    2017-12-01

    Fixed thoracolumbar kyphosis with spinal stenosis in adult patients with achondroplasia presents a challenging issue. We describe the first case in which spondylectomy and minimally invasive lateral access interbody arthrodesis were used for the treatment of fixed severe thoracolumbar kyphosis and lumbar spinal canal stenosis in an adult with achondroplasia. A 61-year-old man with a history of achondroplastic dwarfism presented with low back pain and radiculopathy and neurogenic claudication. Plain radiographs revealed a high-grade thoracolumbar kyphotic deformity with diffuse degenerative changes in the lumbar spine. The apex was located at L2, the local kyphotic angle from L1 to L3 was 105°, and the anterior area was fused from the L1 to L3 vertebrae. MRI revealed significant canal and lateral recess stenosis secondary to facet hypertrophy. We planned a front-back correction of the anterior and posterior spinal elements. We first performed anterior release at the fused part from L1 to L3 and XLIF at L3/4 and L4/5. Next, the patient was placed in the prone position. Spondylectomy at the L2 vertebra and posterior fusion from T10 to L5 were performed. Postoperative radiographs revealed L1 to L3 kyphosis of 32°. No complications occurred during or after surgery. Postoperatively, the patient's low back pain and neurological claudication were resolved. No worsening of kyphosis was observed 24 months postoperatively. Circumferential decompression of the spinal cord at the apical vertebral level and decompression of lumbar canal stenosis were necessary. Front-back correction of the anterior and posterior spinal elements via spondylectomy and lateral lumbar interbody fusion is a reasonable surgical option for thoracolumbar kyphosis and developmental canal stenosis in patients with achondroplasia.

  5. Effect of Smoking Status on Successful Arthrodesis, Clinical Outcome, and Complications After Anterior Lumbar Interbody Fusion (ALIF).

    Science.gov (United States)

    Phan, Kevin; Fadhil, Matthew; Chang, Nicholas; Giang, Gloria; Gragnaniello, Cristian; Mobbs, Ralph J

    2018-02-01

    Anterior lumbar interbody fusion (ALIF) is a surgical technique indicated for the treatment of several lumbar pathologies. Smoking has been suggested as a possible cause of reduced fusion rates after ALIF, although the literature regarding the impact of smoking status on lumbar spine surgery is not well established. This study aims to assess the impact of perioperative smoking status on the rates of perioperative complications, fusion, and adverse clinical outcomes in patients undergoing ALIF surgery. A retrospective analysis was performed on a prospectively maintained database of 137 patients, all of whom underwent ALIF surgery by the same primary spine surgeon. Smoking status was defined by the presence of active smoking in the 2 weeks before the procedure. Outcome measures included fusion rates, surgical complications, Short-Form 12, and Oswestry Disability Index. Patients were separated into nonsmokers (n = 114) and smokers (n = 23). Univariate analysis demonstrated that the percentage of patients with successful fusion differed significantly between the groups (69.6% vs. 85.1%, P = 0.006). Pseudarthrosis rates were shown to be significantly associated with perioperative smoking. Results for other postoperative complications and clinical outcomes were similar for both groups. On multivariate analysis, the rate of failed fusion was significantly greater for smokers than nonsmokers (odds ratio 37.10, P = 0.002). The rate of successful fusion after ALIF surgery was found to be significantly lower for smokers compared with nonsmokers. No significant association was found between smoking status and other perioperative complications or adverse clinical outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Preliminary results of anterior lumbar interbody fusion, anterior column realignment for the treatment of sagittal malalignment.

    Science.gov (United States)

    Hosseini, Pooria; Mundis, Gregory M; Eastlack, Robert K; Bagheri, Ramin; Vargas, Enrique; Tran, Stacie; Akbarnia, Behrooz A

    2017-12-01

    OBJECTIVE Sagittal malalignment decreases patients' quality of life and may require surgical correction to achieve realignment goals. High-risk posterior-based osteotomy techniques are the current standard treatment for addressing sagittal malalignment. More recently, anterior lumbar interbody fusion, anterior column realignment (ALIF ACR) has been introduced as an alternative for correction of sagittal deformity. The objective of this paper was to report clinical and radiographic results for patients treated using the ALIF-ACR technique. METHODS A retrospective study of 39 patients treated with ALIF ACR was performed. Patient demographics, operative details, radiographic parameters, neurological assessments, outcome measures, and preoperative, postoperative, and mean 1-year follow-up complications were studied. RESULTS The patient population comprised 39 patients (27 females and 12 males) with a mean follow-up of 13.3 ± 4.7 months, mean age of 66.1 ± 11.6 years, and mean body mass index of 27.3 ± 6.2 kg/m 2 . The mean number of ALIF levels treated was 1.5 ± 0.5. Thirty-three (84.6%) of 39 patients underwent posterior spinal fixation and 33 (84.6%) of 39 underwent posterior column osteotomy, of which 20 (60.6%) of 33 procedures were performed at the level of the ALIF ACR. Pelvic tilt, sacral slope, and pelvic incidence were not statistically significantly different between the preoperative and postoperative periods and between the preoperative and 1-year follow-up periods (except for PT between the preoperative and 1-year follow-up, p = 0.018). Sagittal vertical axis, T-1 spinopelvic inclination, lumbar lordosis, pelvic incidence-lumbar lordosis mismatch, intradiscal angle, and motion segment angle all improved from the preoperative to postoperative period and the preoperative to 1-year follow-up (p < 0.05). The changes in motion segment angle and intradiscal angle achieved in the ALIF-ACR group without osteotomy compared with the ALIF-ACR group with osteotomy

  7. Treatment of degenerative lumbar spondylolisthesis by using minimally invasive transforaminal lumbar interbody fusion and percutaneous pedicle screw fixation

    Directory of Open Access Journals (Sweden)

    Hao WU

    2016-04-01

    Full Text Available Objective To discuss clinical therapeutic effects of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF combined with percutaneous pedicle screw fixation for degenerative lumbar spondylolisthesis (DLS.  Methods A total of 32 DLS patients treated by MIS-TLIF and percutaneous pedicle screw fixation from January 2013 to September 2015 in Xuanwu Hospital, Capital Medical University were retrospectively reviewed. Visual Analogue Scale (VAS, Oswestry Disability Index (ODI and Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36 scores were assessed and compared between preoperation and one week, 3 months after operation and in the last follow-up. Lumbar lordosis angle, coronal Cobb angle, coronal and sagittal body shifting, complication, the degree of spondylolisthesis (Meyerding classification and the rate of spondylolisthesis were measured according to preoperative and postoperative spinal X-ray examination. Fusion rate was evaluated according to X-rays or CT in the last follow-up, and MRI was used to assess the degree of decompression.  Results Thirty-two patients were under test with mean operation time 160 min, intraoperative blood loss 120 ml, postoperative hospital stay 7.22 d and follow-up 10.83 months. Decompression and fusion levels ranged from L2-S1 and interbody fusion was performed in 32 patients and 41 levels were fused. Compared with preoperation, the VAS and ODI scores were significantly increased at one week, 3 months after operation and in the last follow-up (P = 0.000, for all, while SF-36 score (P = 0.002, 0.000, 0.000, lumbar lordotic angle (P = 0.000, for all, coronal Cobb angle (P = 0.000, for all and slippage rate (P = 0.000, for all were significantly decreased. The fusion rate was 92.22%, and the improvement rate of ODI was (80.51 ± 6.02% in the last follow-up. There were 3 cases appeared complications, including one case of infection and 2 cases of cerebrospinal fluid (CSF fistula, and were

  8. Clinico-radiological profile of indirect neural decompression using cage or auto graft as interbody construct in posterior lumbar interbody fusion in spondylolisthesis: Which is better?

    Directory of Open Access Journals (Sweden)

    Q R Abdul

    2011-01-01

    Full Text Available Study design: A prospective clinical study of posterior lumbar interbody fusion in grade I and II degenerative spondylolisthesis was conducted between Mar 2007 and Aug 2008. Purpose: The objective was to assess the clinicoradiological profile of structural v/s nonstructural graft on intervertebral disc height and its consequences on the low back pain (LBP assessed by Visual analog score (VAS score and oswestry disability index (ODI . This study involved 28 patients. Inclusion criteria: Age of 30-70 years, symptomatic patient with disturbed Activities of daily living (ADL, single-level L4/L5 or L5/S1 grade I or grade II degenerative spondylolisthesis. Exclusion criteria: Patients with osteoporosis, recent spondylodiscitis, subchondral sclerosis, visual and cognitive impairment and all other types of spondylolisthesis. All the patients underwent short-segment posterior fixation using CD2 or M8 instrumentation, laminectomy discectomy, reduction and distraction of the involved vertebral space. In 53.5% (n = 15 of the patients, snugly fitted local bone chips were used while in 46.4% (n = 13 of the patients, cage was used. Among the cage group, titanium cage was used in nine (32.1% and PEEK cages were used in four (14.2% patients. In one patient, a unilateral PEEK cage was used. The mean follow-up period was 24 months. Among the 28 patients, 67.8% (n = 19 were females and 32.14% (n = 9 were males. 68.24% (n = 18 had L4/L5 and 35.71% (n = 10 had L5/S1 spondylolisthesis. 39.28% (n = 11 were of grade I and 60.71% (n = 17 were of grade II spondylolisthesis. Conclusions: There was a statistically significant correlation (P < 0.012 and P < 0.027 between the change in disc height achieved and the improvement in VAS score in both the graft group and the cage group. The increment in disc height and VAS score was significantly better in the cage group (2 mm ± SD vis-a-vis 7.2 [88%] than the graft group (1.2 mm ± SD vis-a-vis 5 [62 %].

  9. Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation in surgical treatment for single-segment lumbar spinal tuberculosis.

    Science.gov (United States)

    Zeng, Hao; Wang, Xiyang; Zhang, Penghui; Peng, Wei; Liu, Zheng; Zhang, Yupeng

    2015-01-01

    The aim of this study is to determine the feasibility and efficacy of surgical management of single-segment lumbar spinal tuberculosis (TB) by using single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation. Seventeen cases of single-segment lumbar TB were treated with single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation. The mean follow-up was 36.9 months (range: 24-62 months). The kyphotic angle ranged from 15.2-35.1° preoperatively, with an average measurement of 27.8°. The American Spinal Injury Association (ASIA) score system was used to evaluate the neurological deficits and erythrocyte sedimentation rate (ESR) used to judge the activity of TB. Spinal TB was completely cured in all 17 patients. There was no recurrent TB infection. The postoperative kyphotic angle was 6.6-10.2°, 8.1° in average, and there was no significant loss of the correction at final follow-up. Solid fusion was achieved in all cases. Neurological condition in all patients was improved after surgery. Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation can be a feasible and effective method the in treatment of single-segment lumbar spinal TB.

  10. Preservation or Restoration of Segmental and Regional Spinal Lordosis Using Minimally Invasive Interbody Fusion Techniques in Degenerative Lumbar Conditions: A Literature Review.

    Science.gov (United States)

    Uribe, Juan S; Myhre, Sue Lynn; Youssef, Jim A

    2016-04-01

    A literature review. The purpose of this study was to review lumbar segmental and regional alignment changes following treatment with a variety of minimally invasive surgery (MIS) interbody fusion procedures for short-segment, degenerative conditions. An increasing number of lumbar fusions are being performed with minimally invasive exposures, despite a perception that minimally invasive lumbar interbody fusion procedures are unable to affect segmental and regional lordosis. Through a MEDLINE and Google Scholar search, a total of 23 articles were identified that reported alignment following minimally invasive lumbar fusion for degenerative (nondeformity) lumbar spinal conditions to examine aggregate changes in postoperative alignment. Of the 23 studies identified, 28 study cohorts were included in the analysis. Procedural cohorts included MIS ALIF (two), extreme lateral interbody fusion (XLIF) (16), and MIS posterior/transforaminal lumbar interbody fusion (P/TLIF) (11). Across 19 study cohorts and 720 patients, weighted average of lumbar lordosis preoperatively for all procedures was 43.5° (range 28.4°-52.5°) and increased 3.4° (9%) (range -2° to 7.4°) postoperatively (P lordosis increased, on average, by 4° from a weighted average of 8.3° preoperatively (range -0.8° to 15.8°) to 11.2° at postoperative time points (range -0.2° to 22.8°) (P lordosis and change in lumbar lordosis (r = 0.413; P = 0.003), wherein lower preoperative lumbar lordosis predicted a greater increase in postoperative lumbar lordosis. Significant gains in both weighted average lumbar lordosis and segmental lordosis were seen following MIS interbody fusion. None of the segmental lordosis cohorts and only two of the 19 lumbar lordosis cohorts showed decreases in lordosis postoperatively. These results suggest that MIS approaches are able to impact regional and local segmental alignment and that preoperative patient factors can impact the extent of correction gained

  11. Hydrogen Gas Production in a Stand-Alone Wind Farm

    Directory of Open Access Journals (Sweden)

    M. Naziry Kordkandy

    2017-04-01

    Full Text Available This paper is analyzing the operation of a stand-alone wind farm with variable speed turbines, permanent magnet synchronous generators (PMSG and a system for converting wind energy during wind speed variations. On this paper, the design and modeling of a wind system which uses PMSG’s to provide the required power of a hydrogen gas electrolyzer system, is discussed. This wind farm consists of three wind turbines, boost DC-DC converters, diode full bridge rectifiers, permanent magnet synchronous generators, MPPT control and a hydrogen gas electrolyzer system. The MPPT controller based on fuzzy logic is designed to adjust the duty ratio of the boost DC-DC converters to absorb maximum power. The proposed fuzzy logic controller assimilates, with (PSF MPPT algorithm which generally used to absorb maximum power from paralleled wind turbines and stores it in form of hydrogen gas. The system is modeled and its behavior is studied using the MATLAB software.

  12. Magnetic field measurements near stand-alone transformer stations.

    Science.gov (United States)

    Kandel, Shaiela; Hareuveny, Ronen; Yitzhak, Nir-Mordechay; Ruppin, Raphael

    2013-12-01

    Extremely low-frequency (ELF) magnetic field (MF) measurements around and above three stand-alone 22/0.4-kV transformer stations have been performed. The low-voltage (LV) cables between the transformer and the LV switchgear were found to be the major source of strong ELF MFs of limited spatial extent. The strong fields measured above the transformer stations support the assessment method, to be used in future epidemiological studies, of classifying apartments located right above the transformer stations as highly exposed to MFs. The results of the MF measurements above the ground around the transformer stations provide a basis for the assessment of the option of implementing precautionary procedures.

  13. Integral type small PWR with stand-alone safety

    International Nuclear Information System (INIS)

    Makihara, Yoshiaki

    2001-01-01

    A feasibility study is achieved on an integral type small PWR with stand-alone safety. It is designed to have the following features. (1) The coolant does not leak out at any accidental condition. (2) The fuel failure does never occur while it is supposed on the large scale PWR at the design base accident. (3) At any accidental condition the safety is secured without any support from the outside (stand-alone safety secure). (4) It has self-regulating characteristics and easy controllability. The above features can be satisfied by integrate the steam generator and CRDM in the reactor vessel while the pipe line break has to be considered on the conventional PWR. Several counter measures are planned to satisfy the above features. The economy feature is also attained by several simplifications such as (1) elimination of main coolant piping and pressurizer by the integration of primary cooling system and self-pressurizing, (2) elimination of RCP by application of natural circulating system, (3) elimination of ECCS and accumulator by application of static safety system, (4) large scale volume reduction of the container vessel by application of integrated primary cooling system, (5) elimination of boric acid treatment by deletion of chemical shim. The long operation period such as 10 years can be attained by the application of Gd fuel in one batch refueling. The construction period can be shortened by the standardizing the design and the introduction of modular component system. Furthermore the applicability of the reduced modulation core is also considered. (K. Tsuchihashi)

  14. Lateral retroperitoneal transpsoas interbody fusion in a patient with achondroplastic dwarfism.

    Science.gov (United States)

    Staub, Blake N; Holman, Paul J

    2015-02-01

    The authors present the first reported use of the lateral retroperitoneal transpsoas approach for interbody arthrodesis in a patient with achondroplastic dwarfism. The inherent anatomical abnormalities of the spine present in achondroplastic dwarfism predispose these patients to an increased incidence of spinal deformity as well as neurogenic claudication and potential radicular symptoms. The risks associated with prolonged general anesthesia and intolerance of significant blood loss in these patients makes them ideal candidates for minimally invasive spinal surgery. The patient in this case was a 51-year-old man with achondroplastic dwarfism who had a history of progressive claudication and radicular pain despite previous extensive lumbar laminectomies. The lateral retroperitoneal transpsoas approach was used for placement of interbody cages at L1/2, L2/3, L3/4, and L4/5, followed by posterior decompression and pedicle screw instrumentation. The patient tolerated the procedure well with no complications. Postoperatively his claudicatory and radicular symptoms resolved and a CT scan revealed solid arthrodesis with no periimplant lucencies.

  15. Comparative Study of the Difference of Perioperative Complication and Radiologic Results: MIS-DLIF (Minimally Invasive Direct Lateral Lumbar Interbody Fusion) Versus MIS-OLIF (Minimally Invasive Oblique Lateral Lumbar Interbody Fusion).

    Science.gov (United States)

    Jin, Jie; Ryu, Kyeong-Sik; Hur, Jung-Woo; Seong, Ji-Hoon; Kim, Jin-Sung; Cho, Hyun-Jin

    2018-02-01

    Retrospective observatory analysis. The purpose of this study was to compare the incidence of perioperative complication, difference of cage location, and sagittal alignment between minimally invasive oblique lateral lumbar interbody fusion (MIS-OLIF) and MIS-direct lateral lumbar interbody fusion (DLIF) in the cases of single-level surgery at L4-L5. MIS-DLIF using tubular retractor has been used for the treatment of lumbar degenerative diseases; however, blunt transpsoas dissection poses a risk of injury to the lumbar plexus. As an alternative, MIS-OLIF uses a window between the prevertebral venous structures and psoas muscle. A total of 43 consecutive patients who underwent MIS-DLIF or MIS-OLIF for various L4/L5 level pathologies between November 2011 and April 2014 by a single surgeon were retrospectively reviewed. A complication classification based on the relation to surgical procedure and effect duration was used. Perioperative complications until 3-month postoperatively were reviewed for the patients. Radiologic results including the cage location and sagittal alignment were also assessed with plain radiography. There were no significant statistical differences in perioperative parameters and early clinical outcome between 2 groups. Overall, there were 13 (59.1%) approach-related complications in the DLIF group and 3 (14.3%) in the OLIF group. In the DLIF group, 3 (45.6%) were classified as persistent, however, there was no persistent complication in the OLIF group. In the OLIF group, cage is located mostly in the middle 1/3 of vertebral body, significantly increasing posterior disk space height and foraminal height compared with the DLIF group. Global and segmental lumbar lordosis was greater in the DLIF group due to anterior cage position without statistical significance. In our report of L4/L5 level diseases, the OLIF technique may decrease approach-related perioperative morbidities by eliminating the risk of unwanted muscle and nerve manipulations. Using

  16. Increased incidence of pseudarthrosis after unilateral instrumented transforaminal lumbar interbody fusion in patients with lumbar spondylosis: Clinical article.

    Science.gov (United States)

    Gologorsky, Yakov; Skovrlj, Branko; Steinberger, Jeremy; Moore, Max; Arginteanu, Marc; Moore, Frank; Steinberger, Alfred

    2014-10-01

    Transforaminal lumbar interbody fusion (TLIF) with segmental pedicular instrumentation is a well established procedure used to treat lumbar spondylosis with or without spondylolisthesis. Available biomechanical and clinical studies that compared unilateral and bilateral constructs have produced conflicting data regarding patient outcomes and hardware complications. A prospective cohort study was undertaken by a group of neurosurgeons. They prospectively enrolled 80 patients into either bilateral or unilateral pedicle screw instrumentation groups (40 patients/group). Demographic data collected for each group included sex, age, body mass index, tobacco use, and Workers' Compensation/litigation status. Operative data included segments operated on, number of levels involved, estimated blood loss, length of hospital stay, and perioperative complications. Long-term outcomes (hardware malfunction, wound dehiscence, and pseudarthrosis) were recorded. For all patients, preoperative baseline and 6-month postoperative scores for Medical Outcomes 36-Item Short Form Health Survey (SF-36) outcomes were recorded. Patient follow-up times ranged from 37 to 63 months (mean 52 months). No patients were lost to follow-up. The patients who underwent unilateral pedicle screw instrumentation (unilateral cohort) were slightly younger than those who underwent bilateral pedicle screw instrumentation (bilateral cohort) (mean age 42 vs. 47 years, respectively; p = 0.02). No other significant differences were detected between cohorts with regard to demographic data, mean number of lumbar levels operated on, or distribution of the levels operated on. Estimated blood loss was higher for patients in the bilateral cohort, but length of stay was similar for patients in both cohorts. The incidence of pseudarthrosis was significantly higher among patients in the unilateral cohort (7 patients [17.5%]) than among those in the bilateral cohort (1 patient [2.5%]) (p = 0.02). Wound dehiscence occurred for

  17. Can cantilever transforaminal lumbar interbody fusion (C-TLIF) maintain segmental lordosis for degenerative spondylolisthesis on a long-term basis?

    Science.gov (United States)

    Kida, Kazunobu; Tadokoro, Nobuaki; Kumon, Masashi; Ikeuchi, Masahiko; Kawazoe, Tateo; Tani, Toshikazu

    2014-03-01

    To determine if cantilever transforaminal lumbar interbody fusion (C-TLIF) using the crescent-shaped titanium interbody spacer (IBS) favors acquisition of segmental and lumbar lordosis even for degenerative spondylolisthesis (DS) on a long-term basis. We analyzed 23 consecutive patients who underwent C-TLIF with pedicle screw instrumentations fixed with compression for a single-level DS. Measurements on the lateral radiographs taken preoperatively, 2 weeks postoperatively and at final follow-up included disc angle (DA), segmental angle (SA), lumbar lordosis (LL), disc height (%DH) and slip rate (%slip). There was a good functional recovery with 100 % fusion rate at the mean follow-up of 62 months. Segmental lordosis (DA and SA) and %DH initially increased, but subsequently decreased with the subsidence of the interbody spacer, resulting in a significant increase (p = 0.046) only in SA from 13.2° ± 5.5° preoperatively to 14.7° ± 6.4° at the final follow-up. Changes of LL and %slip were more consistent without correction loss finally showing an increase of LL by 3.6° (p = 0.005) and a slip reduction by 6.7 % (p lordosis on a long-term basis, which would be of benefit in preventing hypolordosis-induced back pain and the adjacent level disc disease.

  18. A control strategy for PV stand-alone applications

    Science.gov (United States)

    Slouma, S.; Baccar, H.

    2015-04-01

    This paper proposes a stand-alone photovoltaic (PV) system study in domestic applications. Because of the decrease in power of photovoltaic module as a consequence of changes in solar radiation and temperature which affect the photovoltaic module performance, the design and control of DC-DC buck converter was proposed for providing power to the load from a photovoltaic source.In fact, the control of this converter is carried out with integrated MPPT (Maximum Power Point Tracking) algorithm which ensures a maximum energy generated by the PV arrays. Moreover, the output stage is composed by a battery energy storage system, dc-ac inverter, LCL filter which enables higher efficiency, low distortion ac waveforms and low leakage currents. The control strategy adopted is cascade control composed by two regulation loops.Simulations performed with PSIM software were able to validate the control system.The realization and testing of the photovoltaic system were achieved in the Photovoltaic laboratory of the Centre for Research and Energy Technologies at the Technopark Borj Cedria. Experimental results verify the effeciency of the proposed system.

  19. A control strategy for PV stand-alone applications

    International Nuclear Information System (INIS)

    Slouma, S; Baccar, H

    2015-01-01

    This paper proposes a stand-alone photovoltaic (PV) system study in domestic applications. Because of the decrease in power of photovoltaic module as a consequence of changes in solar radiation and temperature which affect the photovoltaic module performance, the design and control of DC-DC buck converter was proposed for providing power to the load from a photovoltaic source.In fact, the control of this converter is carried out with integrated MPPT (Maximum Power Point Tracking) algorithm which ensures a maximum energy generated by the PV arrays. Moreover, the output stage is composed by a battery energy storage system, dc-ac inverter, LCL filter which enables higher efficiency, low distortion ac waveforms and low leakage currents. The control strategy adopted is cascade control composed by two regulation loops.Simulations performed with PSIM software were able to validate the control system.The realization and testing of the photovoltaic system were achieved in the Photovoltaic laboratory of the Centre for Research and Energy Technologies at the Technopark Borj Cedria. Experimental results verify the effeciency of the proposed system

  20. Improving efficiency of a regional stand alone bone bank.

    Science.gov (United States)

    Warnock, Jonathan M; Rowan, Clare H; Davidson, Helen; Millar, Ciara; McAlinden, M Gavan

    2016-03-01

    The introduction of a stand-alone Bone Bank in our Regional Orthopaedic Hospital has improved the availability of femoral head allograft. Benninger et al. (Bone Joint J 96-B:1307-1311, 2014), demonstrated their institutions bank to be cost effective despite a 30 % discard rate for harvested allograft. We sought to audit our own discard rates and subsequent cost-effectiveness of our bone bank. Donor recruitment. Before approaching a potential donor, our establishment's nurse specialists review their clinical notes and biochemical laboratory results, available on a regional Electronic Care Records. They view femoral head architecture on radiographs against set criteria, Patient Archive and Communication system (SECTRA, Sweden). In total 1383 femoral heads were harvested, 247 were discarded giving an overall rate of 17.9 %. The most common reasons for discard of harvested graft was a positive microbiology/bacteriology result, n = 96 (38.9 %). After a rise in discard rates in 2007, we have steadily reduced our discard rates since 2006/2007 (28.2 %), 2008/2009 (17 %), 2010/2011 (14.8 %), and finally to 10.3 % in 2012/2013. In the current financial year, our cost to harvest, test, store and release a femoral head is £ 610. With a structured donor recruitment process and unique pre-operative radiographic analysis we have successfully reduced our discard rates bi-annually making our bone bank increasingly cost-effective.

  1. The Stand-alone Heliostat; El Heliostato Autonomo

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Navajas, G.; Egea Gea, A. [Ciemat. Madrid (Spain)

    2000-07-01

    The first Autonomous Heliostat has been developed by CIEMAT at PSA facilities in Almeria. This heliostat is an innovative approach to reducing the civil engineering work costs in heliostat fields of central tower plants. Channels, cables and other electric elements have been eliminated in the new heliostat. Thus, one 70-m''2, classical T glass/metal heliostat has been adapted to include all the new stand-alone concept components. A PV system is able to drive two sun-tracking DC motors between 5 and 24 Vdc, 0 and 15A. The heliostat communicates with the control room 400-m away by using a radio-modern working at 9600 baud. An anemometer, a wind switcher, light and ambient temperature sensors have been installed on the heliostat for self-protection decision-making. A PV panel integrated into the heliostat reflecting surface, eliminates cabling and other elements required for a conventional power supply. Communication lines between master control and local control have been replaced by radio-modern. Testing has validated the technical feasibility of the prototype and quantified the real consumption and efficiencies of new elements. The extra costs produced by the autonomous concepts are compared with the cost of civil work in conventional heliostat field. (Author) 8 refs.

  2. The Stand-alone Heliostat; El Heliostato Autonomo

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Navajas, G; Egea Gea, A [Ciemat. Madrid (Spain)

    2000-07-01

    The first Autonomous Heliostat has been developed by CIEMAT at PSA facilities in Almeria. This heliostat is an innovative approach to reducing the civil engineering work costs in heliostat fields of central tower plants. Channels, cables and other electric elements have been eliminated in the new heliostat. Thus, one 70-m''2, classical T glass/metal heliostat has been adapted to include all the new stand-alone concept components. A PV system is able to drive two sun-tracking DC motors between 5 and 24 Vdc, 0 and 15A. The heliostat communicates with the control room 400-m away by using a radio-modern working at 9600 baud. An anemometer, a wind switcher, light and ambient temperature sensors have been installed on the heliostat for self-protection decision-making. A PV panel integrated into the heliostat reflecting surface, eliminates cabling and other elements required for a conventional power supply. Communication lines between master control and local control have been replaced by radio-modern. Testing has validated the technical feasibility of the prototype and quantified the real consumption and efficiencies of new elements. The extra costs produced by the autonomous concepts are compared with the cost of civil work in conventional heliostat field. (Author) 8 refs.

  3. JAERI Fuel Cleanup System (J-FCU) stand-alone tritium test at the TSTA

    International Nuclear Information System (INIS)

    Konishi, Satoshi; Hayashi, Takumi; Inoue, Masahiko

    1993-03-01

    JAERI designed, fabricated, and installed the JAERI Fuel Cleanup System (J-FCU) as a subsystem of simulated fusion fuel loop at the TSTA. The main function of the J-FCU is to purify and to recover hydrogen isotopes from simulated plasma exhaust while exhausting tritium free impurities. After a lot of deuterium tests, a first tritium test of the J-FCU was performed with one gram of tritium at the TSTA on June 1991. Main purpose of this test was to evaluate the total integrity and function of the J-FCU system with a DT mixture. Through this test, the J-FCU was operated well and its function with tritium was demonstrated. This report describes the detail test results of the J-FCU first tritium test and discuss its functions by stand-alone mode. Residual tritium inventory of the J-FCU system was also discussed. (author)

  4. The Efficacy of Vitamin C on Postoperative Outcomes after Posterior Lumbar Interbody Fusion: A Randomized, Placebo-Controlled Trial.

    Science.gov (United States)

    Lee, Gun Woo; Yang, Han Seok; Yeom, Jin S; Ahn, Myun-Whan

    2017-09-01

    Vitamin C has critical features relavant to postoperative pain management and functional improvement; however, no study has yet evaluated the effectiveness of vitamin C on improving the surgical outcomes for spine pathologies. Thus, this study aimed to explore the impact of vitamin C on postoperative outcomes after single-level posterior lumbar interbody fusion (PLIF) for lumbar spinal stenosis in prospectively randomized design. We conducted a 1-year prospective, randomized, placebo-controlled, double-blind study to evaluate the impact of vitamin C on the postoperative outcomes after PLIF surgery. A total of 123 eligible patients were randomly assigned to either group A (62 patients with vitamin C) or group B (61 patients with placebo). Patient follow-up was continued for at least 1 year after surgery. The primary outcome measure was pain intensity in the lower back using a visual analogue scale. The secondary outcome measures were: (1) the clinical outcome assessed using the Oswestry Disability Index (ODI); (2) the fusion rate assessed using dynamic radiographs and computed tomography scans; and (3) complications. Pain intensity in the lower back was significantly improved in both groups compared with preoperative pain intensity, but no significant difference was observed between the 2 groups over the follow-up period. The ODI score of group A at the third postoperative month was significantly higher than the score of group B. After the sixth postoperative month, the ODI score of group A was slightly higher than the score of group B; however, this difference was not significant. The fusion rates at 1 year after surgery and the complication rates were not significantly different between the 2 groups. Postoperative pain intensity, the primary outcome measure, was not significantly different at 1 year after surgery between the 2 groups. However, vitamin C may be associated with improving functional status after PLIF surgery, especially during the first 3

  5. Two-level anterior lumbar interbody fusion with percutaneous pedicle screw fixation. A minimum 3-year follow-up study

    International Nuclear Information System (INIS)

    Lee, Dong-Yeob; Lee, Sang-Ho; Maeng, Dae-Hyeon

    2010-01-01

    The clinical and radiological outcomes of two-level anterior lumbar interbody fusion (ALIF) with percutaneous pedicle screw fixation (PSF) were evaluated in 24 consecutive patients who underwent two level ALIF with percutaneous PSF for segmental instability and were followed up for more than 3 years. Clinical outcomes were assessed using a visual analogue scale (VAS) score and the Oswestry Disability Index (ODI). Sagittal alignment, bone union, and adjacent segment degeneration (ASD) were assessed using radiography and magnetic resonance imaging. The mean age of the patients at the time of operation was 56.3 years (range 39-70 years). Minor complications occurred in 2 patients in the perioperative period. At a mean follow-up duration of 39.4 months (range 36-42 months), VAS scores for back pain and leg pain, and ODI score decreased significantly (from 6.5, 6.8, and 46.9% to 3.0, 1.9, and 16.3%, respectively). Clinical success was achieved in 22 of the 24 patients. The mean segmental lordosis, whole lumbar lordosis, and sacral tilt significantly increased after surgery (from 25.1deg, 39.2deg, and 32.6deg to 32.9deg, 44.5deg, and 36.6deg, respectively). Solid fusion was achieved in 21 patients. ASD was found in 8 of the 24 patients. No patient underwent revision surgery due to nonunion or ASD. Two-level ALIF with percutaneous PSF yielded satisfactory clinical and radiological outcomes and could be a useful alternative to posterior fusion surgery. (author)

  6. Effect of Lumbar Lordosis on the Adjacent Segment in Transforaminal Lumbar Interbody Fusion: A Finite Element Analysis.

    Science.gov (United States)

    Zhao, Xin; Du, Lin; Xie, Youzhuan; Zhao, Jie

    2018-06-01

    We used a finite element (FE) analysis to investigate the biomechanical changes caused by transforaminal lumbar interbody fusion (TLIF) at the L4-L5 level by lumbar lordosis (LL) degree. A lumbar FE model (L1-S5) was constructed based on computed tomography scans of a 30-year-old healthy male volunteer (pelvic incidence,= 50°; LL, 52°). We investigated the influence of LL on the biomechanical behavior of the lumbar spine after TLIF in L4-L5 fusion models with 57°, 52°, 47°, and 40° LL. The LL was defined as the angle between the superior end plate of L1 and the superior end plate of S1. A 150-N vertical axial preload was imposed on the superior surface of L3. A 10-N/m moment was simultaneously applied on the L3 superior surface along the radial direction to simulate the 4 basic physiologic motions of flexion, extension, lateral bending, and torsion in the numeric simulations. The range of motion (ROM) and intradiscal pressure (IDP) of L3-L4 were evaluated and compared in the simulated cases. In all motion patterns, the ROM and IDP were both increased after TLIF. In addition, the decrease in lordosis generally increased the ROM and IDP in all motion patterns. This FE analysis indicated that decreased spinal lordosis may evoke overstress of the adjacent segment and increase the risk of the pathologic development of adjacent segment degeneration; thus, adjacent segment degeneration should be considered when planning a spinal fusion procedure. Copyright © 2018. Published by Elsevier Inc.

  7. Two-level anterior lumbar interbody fusion with percutaneous pedicle screw fixation. A minimum 3-year follow-up study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong-Yeob; Lee, Sang-Ho; Maeng, Dae-Hyeon [Wooridul Spine Hospital, Seoul (Korea, Republic of)

    2010-08-15

    The clinical and radiological outcomes of two-level anterior lumbar interbody fusion (ALIF) with percutaneous pedicle screw fixation (PSF) were evaluated in 24 consecutive patients who underwent two level ALIF with percutaneous PSF for segmental instability and were followed up for more than 3 years. Clinical outcomes were assessed using a visual analogue scale (VAS) score and the Oswestry Disability Index (ODI). Sagittal alignment, bone union, and adjacent segment degeneration (ASD) were assessed using radiography and magnetic resonance imaging. The mean age of the patients at the time of operation was 56.3 years (range 39-70 years). Minor complications occurred in 2 patients in the perioperative period. At a mean follow-up duration of 39.4 months (range 36-42 months), VAS scores for back pain and leg pain, and ODI score decreased significantly (from 6.5, 6.8, and 46.9% to 3.0, 1.9, and 16.3%, respectively). Clinical success was achieved in 22 of the 24 patients. The mean segmental lordosis, whole lumbar lordosis, and sacral tilt significantly increased after surgery (from 25.1deg, 39.2deg, and 32.6deg to 32.9deg, 44.5deg, and 36.6deg, respectively). Solid fusion was achieved in 21 patients. ASD was found in 8 of the 24 patients. No patient underwent revision surgery due to nonunion or ASD. Two-level ALIF with percutaneous PSF yielded satisfactory clinical and radiological outcomes and could be a useful alternative to posterior fusion surgery. (author)

  8. Late Results of Anterior Cervical Discectomy and Fusion with Interbody Cages

    OpenAIRE

    Da?l?, Murat; Er, Uygur; ?im?ek, Serkan; Bavbek, Murad

    2013-01-01

    Study Design Retrospective analysis. Purpose To evaluate the effectiveness of anterior cervical discectomy with fusion for degenerative cervical disc disease. Overview of Literature Anterior spinal surgery originated in the mid-1950s and graft for fusion was also employed. Currently anterior cervical microdiscectomy and fusion with an intervertebral cage is a widely accepted procedure for treatment of cervical disc hernia. Artificial grafts and cages for fusion are preferred because of their ...

  9. Effects of Lumbar Fusion Surgery with ISOBAR Devices Versus Posterior Lumbar Interbody Fusion Surgery on Pain and Disability in Patients with Lumbar Degenerative Diseases: A Meta-Analysis.

    Science.gov (United States)

    Su, Shu-Fen; Wu, Meng-Shan; Yeh, Wen-Ting; Liao, Ying-Chin

    2018-06-01

    Purpose/Aim: Lumbar degenerative diseases (LDDs) cause pain and disability and are treated with lumbar fusion surgery. The aim of this study was to evaluate the efficacy of lumbar fusion surgery with ISOBAR devices versus posterior lumbar interbody fusion (PLIF) surgery for alleviating LDD-associated pain and disability. We performed a literature review and meta-analysis conducted in accordance with Cochrane methodology. The analysis included Group Reading Assessment and Diagnostic Evaluation assessments, Jadad Quality Score evaluations, and Risk of Bias in Non-randomized Studies of Interventions assessments. We searched PubMed, MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, the Cochrane Library, ProQuest, the Airiti Library, and the China Academic Journals Full-text Database for relevant randomized controlled trials and cohort studies published in English or Chinese between 1997 and 2017. Outcome measures of interest included general pain, lower back pain, and disability. Of the 18 studies that met the inclusion criteria, 16 examined general pain (802 patients), 5 examined lower back pain (274 patients), and 15 examined disability (734 patients). General pain, lower back pain, and disability scores were significantly lower after lumbar fusion surgery with ISOBAR devices compared to presurgery. Moreover, lumbar fusion surgery with ISOBAR devices was more effective than PLIF for decreasing postoperative disability, although it did not provide any benefit in terms of general pain or lower back pain. Lumbar fusion surgery with ISOBAR devices alleviates general pain, lower back pain, and disability in LDD patients and is superior to PLIF for reducing postoperative disability. Given possible publication bias, we recommend further large-scale studies.

  10. Clinical study on minimally invasive transforaminal lumbar interbody fusion combined with percutaneous pedicle screw fixation for degenerative lumbar scoliosis

    Directory of Open Access Journals (Sweden)

    Hao WU

    2016-04-01

    Full Text Available Objective To discuss the operative essentials and therapeutic effects of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF combined with percutaneous pedicle screw fixation for degenerative lumbar scoliosis (DLS.  Methods A total of 17 DLS patients without prior spinal diseases were treated by MIS-TLIF and percutaneous pedicle screw fixation from January 2013 to September 2015 in Xuanwu Hospital, Capital Medical University. The operation time, intraoperative blood loss, hospital stay, and postoperative complication were recorded in each patient. Visual Analogue Scale (VAS and Oswestry Disability Index (ODI were used to evaluate postoperative improvement of low back and leg pain, and clinical effects were assessed according to Medical Outcome Study 36-Item Short-Form Health Survey (SF-36. Coronal Cobb angle, sagittal lordosis angle and spinal deviation distances on coronal and sagittal plane were measured before operation, one week, 3 months after operation and in the last follow-up in spinal full-length X-ray examination. Fusion rate was calculated according to X-ray or CT scan, and the degree of decompression was evaluated by MRI.  Results Decompression and fusion levels ranged from T12-S1 vertebrae, and interbody fusion was performed in 17 patients and 56 levels were fused. Average operation time was 200 min (180-300 min, intraoperative blood loss was 320 ml (200-1000 ml and hospital stay was 8.21 d (5-12 d. All patients were followed-up for 12.13 months (5-24 months. Compared with preoperation, VAS (P = 0.000, for all and ODI scores (P = 0.000, for all decreased significantly, SF-36 score increased (P = 0.000, for all, coronal Cobb angle (P = 0.000, for all, sagittal lordosis angle (P = 0.000, for all, coronal and sagittal deviation (P = 0.000, for all decreased significantly one week and 3 months after operation and in the last follow-up. The improvement rate of ODI was (86.51 ± 6.02%, fusion rate of vertebral bodies

  11. Neurological Complications after Lateral Transpsoas Approach to Anterior Interbody Fusion with a Novel Flat-Blade Spine-Fixed Retractor

    Directory of Open Access Journals (Sweden)

    Pierce Nunley

    2016-01-01

    Full Text Available Introduction. The lateral lumbar interbody fusion (LLIF surgical approach has potential advantages over other approaches but is associated with some unique neurologic risks due to the proximity of the lumbosacral plexus. The present study analyzed complications following LLIF surgical approach using a novel single flat-blade retractor system. Methods. A retrospective data collection of patients receiving LLIF using a novel single flat-blade retractor system at two institutions in the US. Inclusion criteria were all patients receiving an LLIF procedure with the RAVINE® Lateral Access System (K2M, Inc., Leesburg, VA, USA. There was no restriction on preoperative diagnosis or number of levels treated. Approach-related neurologic complications were collected and analyzed postoperatively through a minimum of one year. Results. Analysis included 253 patients with one to four treated lateral levels. Immediate postoperative neurologic complications were present in 11.1% (28/253 of patients. At one-year follow-up the approach-related neurologic complications resolved in all except 5 patients (2.0%. Conclusion. We observed an 11.1% neurologic complication rate in LLIF procedures. There was resolution of symptoms for most patients by 12-month follow-up, with only 2% of patients with residual symptoms. This supports the hypothesis that the vast majority of approach-related neurologic symptoms are transient.

  12. The Effect of the Retroperitoneal Transpsoas Minimally Invasive Lateral Interbody Fusion on Segmental and Regional Lumbar Lordosis

    Directory of Open Access Journals (Sweden)

    Tien V. Le

    2012-01-01

    Full Text Available Background. The minimally invasive lateral interbody fusion (MIS LIF in the lumbar spine can correct coronal Cobb angles, but the effect on sagittal plane correction is unclear. Methods. A retrospective review of thirty-five patients with lumbar degenerative disease who underwent MIS LIF without supplemental posterior instrumentation was undertaken to study the radiographic effect on the restoration of segmental and regional lumbar lordosis using the Cobb angles on pre- and postoperative radiographs. Mean disc height changes were also measured. Results. The mean follow-up period was 13.3 months. Fifty total levels were fused with a mean of 1.42 levels fused per patient. Mean segmental Cobb angle increased from 11.10° to 13.61° (<0.001 or 22.6%. L2-3 had the greatest proportional increase in segmental lordosis. Mean regional Cobb angle increased from 52.47° to 53.45° (=0.392. Mean disc height increased from 6.50 mm to 10.04 mm (<0.001 or 54.5%. Conclusions. The MIS LIF improves segmental lordosis and disc height in the lumbar spine but not regional lumbar lordosis. Anterior longitudinal ligament sectioning and/or the addition of a more lordotic implant may be necessary in cases where significant increases in regional lumbar lordosis are desired.

  13. Incidence of vascular complications during lateral lumbar interbody fusion: an examination of the mini-open access technique.

    Science.gov (United States)

    Kueper, Janina; Fantini, Gary A; Walker, Brendon R; Aichmair, Alexander; Hughes, Alexander P

    2015-04-01

    This article examines the incidence and management of vascular injury during Lateral Lumbar Interbody Fusion (LLIF). The details of the mini-open access technique are presented. A total of 900 patients who underwent a LLIF at an average 1.94 levels (range: 1-5 levels) by one of six fellowship trained surgeons on 1,754 levels from 2006 to 2013 were identified. The incidence of intraoperative vascular injury was retrospectively determined from the Operative Records. The management of vascular injury was evaluated. The mini-open access adapted by our institution for LLIF is described. The incidence of major vascular complication in our series was 1/900. The incidence of minor vascular injury was 4/900. The overall incidence of vascular injury was calculated to be 0.056 % per case and 0.029 % per level. All minor vascular injuries were identified to be segmental vessel lacerations, which were readily ligated under direct visualization without further extension of the incision with no clinical sequelae. The laceration of the abdominal aorta, the major vascular complication of this series, was emergently repaired through an exploratory laparotomy. None of the patients suffered long-term sequelae from their intraoperative vascular injuries. The mini-open lateral access technique for LLIF provides for minimal risk of vascular injury to the lumbar spine. In the rare event of minor vascular injury, the mini-open access approach allows for immediate visualization, confirmation and repair of the vessel with no long-term sequelae.

  14. Transforaminal lumbar interbody fusion using unilateral pedicle screw fixation plus contralateral translaminar facet screw fixation in lumbar degenerative diseases.

    Science.gov (United States)

    Liu, Fubing; Jiang, Chun; Cao, Yuanwu; Jiang, Xiaoxing; Feng, Zhenzhou

    2014-07-01

    Transforaminal lumbar interbody fusion (TLIF) has been used in lumbar degenerative diseases. Some researchers have applied unilateral fixation in TLIF to reduce operational trauma without compromising the clinical outcome, but it is always suspected biomechanically unstable. The supplementary contralateral translaminar facet screw (cTLFS) seemed to be able to overcome the inherent drawbacks of unilateral pedicle screw (uPS) fixation theoretically. This study evaluates the safety, feasibility and efficacy of TLIF using uPS with cTLFS fixation in the treatment of lumbar degenerative diseases (LDD). 50 patients (29 male) underwent the aforementioned surgical technique for their LDD between December 2009 and April 2012. The results were evaluated based on visual analogue scale (VAS) of the leg and back, Japanese Orthopedic Association (JOA) score and Oswestry Disability Index (ODI) were recorded. The radiographic examinations in form of X-ray, computed tomography (CT) or magnetic resonance imaging was done preoperatively and 1 week, 3 months, 6 months, 12 months and 24 months postoperatively. The student t-test was used for comparison between the preoperative values and postoperative counterparts. P degenerative diseases short termly.

  15. Transforaminal Lumbar Interbody Fusion with Rigid Interspinous Process Fixation: A Learning Curve Analysis of a Surgeon Team's First 74 Cases.

    Science.gov (United States)

    Doherty, Patrick; Welch, Arthur; Tharpe, Jason; Moore, Camille; Ferry, Chris

    2017-05-30

    Studies have shown that a significant learning curve may be associated with adopting minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) with bilateral pedicle screw fixation (BPSF). Accordingly, several hybrid TLIF techniques have been proposed as surrogates to the accepted BPSF technique, asserting that less/fewer fixation(s) or less disruptive fixation may decrease the learning curve while still maintaining the minimally disruptive benefits. TLIF with interspinous process fixation (ISPF) is one such surrogate procedure. However, despite perceived ease of adaptability given the favorable proximity of the spinous processes, no evidence exists demonstrating whether or not the technique may possess its own inherent learning curve. The purpose of this study was to determine whether an intraoperative learning curve for one- and two-level TLIF + ISPF may exist for a single lead surgeon. Seventy-four consecutive patients who received one- or two-Level TLIF with rigid ISPF by a single lead surgeon were retrospectively reviewed. It was the first TLIF + ISPF case series for the lead surgeon. Intraoperative blood loss (EBL), hospitalization length-of-stay (LOS), fluoroscopy time, and postoperative complications were collected. EBL, LOS, and fluoroscopy time were modeled as a function of case number using multiple linear regression methods. A change point was included in each model to allow the trajectory of the outcomes to change during the duration of the case series. These change points were determined using profile likelihood methods. Models were fit using the maximum likelihood estimates for the change points. Age, sex, body mass index (BMI), and the number of treated levels were included as covariates. EBL, LOS, and fluoroscopy time did not significantly differ by age, sex, or BMI (p ≥ 0.12). Only EBL differed significantly by the number of levels (p = 0.026). The case number was not a significant predictor of EBL, LOS, or fluoroscopy time (p ≥ 0

  16. Outcomes of oblique lateral interbody fusion for degenerative lumbar disease in patients under or over 65 years of age.

    Science.gov (United States)

    Jin, Chengzhen; Jaiswal, Milin S; Jeun, Sin-Soo; Ryu, Kyeong-Sik; Hur, Jung-Woo; Kim, Jin-Sung

    2018-02-20

    Oblique lateral interbody fusion (OLIF) offers the solution to problems of anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF). However, OLIF technique for degenerative spinal diseases of elderly patients has been rarely reported. The objective of this study was to determine the clinical and radiological results of OLIF technique for degenerative spinal diseases in patients under or over 65 years of age. Sixty-three patients who underwent OLIF procedure were enrolled, including 29 patients who were less than 65 years of age and 34 patients who were over 65 years of age. Fusion rate, change of disc height and lumbar lordotic angle, Numeric Rating Scale (NRS), return to daily activity, patient's satisfaction rate (PSR), and Oswestry disability index (ODI) were used to assess clinical and functional outcomes. The mean NRS scores for back and leg pain decreased, respectively, from 4.6 and 5.9 to 2.3 and 1.8 in the group A (less than 65 years) and from 4.5 and 6.8 to 2.6 and 2.2 in the group B (over 65 years) at the final follow-up period. The mean ODI scores improved from 48.4 to 24.0% in the group A and from 46.5 to 25.2% in the group B at the final follow-up period. In both groups, the NRS and ODI scores significantly changed preoperatively to postoperatively (p degenerative lumbar diseases in elderly patients showed favorable clinical and radiological outcomes.

  17. Trends Analysis of rhBMP Utilization in Single-Level Posterior Lumbar Interbody Fusion in the United States.

    Science.gov (United States)

    Lao, Lifeng; Cohen, Jeremiah R; Buser, Zorica; Brodke, Darrel S; Youssef, Jim A; Park, Jong-Beom; Yoon, S Tim; Wang, Jeffrey C; Meisel, Hans-Joerg

    2017-10-01

    Retrospective study. Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been widely used in spinal fusion surgery, but there is little information on rhBMP-2 utilization in single-level posterior lumbar interbody fusion (PLIF). The purpose of our study was to evaluate the trends and demographics of rhBMP-2 utilization in single-level PLIF. Patients who underwent single-level PLIF from 2005 to 2011 were identified by searching ICD-9 diagnosis and procedure codes in the PearlDiver Patient Records Database, a national database of orthopedic insurance records. The year of procedure, age, gender, and region of the United States were recorded for each patient. Results were reported for each variable as the incidence of procedures identified per 100 000 patients searched in the database. A total of 2735 patients had single-level PLIF. The average rate of single-level PLIF with rhBMP-2 maintained at a relatively stable level (28% to 31%) from 2005 to 2009, but decreased in 2010 (9.9%) and 2011 (11.8%). The overall incidence of single-level PLIF without rhBMP-2 (0.68 cases per 100 000 patients) was statistically higher ( P level PLIF with rhBMP-2 (0.21 cases per 100 000 patients). The average rate of single-level PLIF with rhBMP-2 utilization was the highest in West (30.1%), followed by Midwest (26.9%), South (20.5%), and Northeast (17.8%). The highest incidence of single-level PLIF with rhBMP-2 was observed in the age group level PLIF. There was a 3-fold increase in the rate of PLIF without rhBMP-2 compared to PLIF with rhBMP-2, with both procedures being mainly done in patients less than 65 years of age.

  18. Comparison of outcomes and safety of using hydroxyapatite granules as a substitute for autograft in cervical cages for anterior cervical discectomy and interbody fusion

    Directory of Open Access Journals (Sweden)

    Hosein Mashhadinezhad

    2014-03-01

    Full Text Available Background:   After cervical discectomy, autogenetic bone is packed into the cage to increase the rate of union between adjacent vertebral bodies, but donor site–related complications can still occur. In this study we evaluate the use   of hydroxyapatite granules as a substitute for autograft for interbody fusion.     Methods:   From November 2008 to November 2011, 236 patients participated in this study. Peek cages were packed with autologous bone grafts taken from the iliac crest in 112 patients and hydroxyapatite (HA granules in 124 patients.   Patients were followed for 12 months. The patients’ neurological signs, results, and complications were fully recorded   throughout the procedure. Radiological imaging was done to assess the fusion rate and settling ratio.     Results:   Formation of bony bridges at the third month was higher in the autograft group versus the granule group. However, there was no difference between both groups at the 12-month follow-up assessment. No difference (     P > 0.05   was found regarding improvement in neurological deficit as well as radicular pain and recovery rate between the two groups. Conclusions:   Interbody fusion cage containing HA granules proved to be an effective treatment for cervical spondylotic radiculopathy and/or myelopathy. Clinical and neurological outcome, radiographic measurement and fusion rate   in cage containing HA are similar and competitive with autograft packed cages.    

  19. Comparison of outcomes and safety of using hydroxyapatite granules as a substitute for autograft in cervical cages for anterior cervical discectomy and interbody fusion

    Directory of Open Access Journals (Sweden)

    Hosein Mashhadinezhad

    2014-03-01

    Full Text Available Background:   After cervical discectomy, autogenetic bone is packed into the cage to increase the rate of union between adjacent vertebral bodies, but donor site–related complications can still occur. In this study we evaluate the use   of hydroxyapatite granules as a substitute for autograft for interbody fusion.     Methods:   From November 2008 to November 2011, 236 patients participated in this study. Peek cages were packed with autologous bone grafts taken from the iliac crest in 112 patients and hydroxyapatite (HA granules in 124 patients.   Patients were followed for 12 months. The patients’ neurological signs, results, and complications were fully recorded   throughout the procedure. Radiological imaging was done to assess the fusion rate and settling ratio.     Results:   Formation of bony bridges at the third month was higher in the autograft group versus the granule group. However, there was no difference between both groups at the 12-month follow-up assessment. No difference (     P > 0.05   was found regarding improvement in neurological deficit as well as radicular pain and recovery rate between the two groups. Conclusions:   Interbody fusion cage containing HA granules proved to be an effective treatment for cervical spondylotic radiculopathy and/or myelopathy. Clinical and neurological outcome, radiographic measurement and fusion rate   in cage containing HA are similar and competitive with autograft packed cages.

  20. [Effect evaluation of over 5 year follow up of unilateral pedicle screw fixation with transforaminal lumbar interbody fusion for lumbar degenerative diseases].

    Science.gov (United States)

    Wang, Chong; Ying, Jin-He; Xie, Pan-Pan; Wu, Xiao-Guang

    2016-07-25

    To evaluate the clinical effects of over 5 year follow up of unilateral pedicle screw fixation with transforaminal lumbar interbody fusion(TLIF) in treating lumbar degenerative diseases. The clinical data of 24 patients with lumbar degenerative disease underwent unilateral pedicle screw fixation with transforaminal lumbar interbody fusion from March 2007 to October 2009, were retrospectively analyzed. There were 13 males and 11 females, aged from 34 to 68 years old with an average of 52 years. Postoperative pain and functional results were analyzed by the visual analogue scale(VAS) and Oswestry Disability Index(ODI). Radiological examination was obtained for each patient to assess the height of intervertebral space, postoperative intervertebral fusion conditions and general complications. All patients were followed up from 5 to 8 years with an average of 6.7 years. VAS scores of low back pain and leg pain decreased from preoperative 7.82±0.71, 8.42±1.24 to postoperative 1.87±0.81, 2.23±1.62, respectively( P degenerative diseases according to over 5 year follow up, however, its indications should be well considered. But the problems such as intervertebral space height of operated side loss and adjacent segment degeneration after unilateral pedicle screw fixation need further clinical study.

  1. [The shor-term clinical outcomes and safety of extreme lateral interbody fusion combined with percutaneous pedicle screw fixation for the treatment of degenerative lumbar disease].

    Science.gov (United States)

    Hu, Xu-Dong; Ma, Wei-Hu; Jiang, Wei-Yu; Ruan, Chao-Yue; Chen, Yun-Lin

    2017-02-25

    To evaluate the early efficacy and safety of extreme lateral interbody fusion (XLIF) combined with percutaneous pedicle screw fixation for lumbar degenerative disease. From January 2013 to June 2014, 13 patients with degenerative lumbar disease were treated with XLIF combined with percutaneous pedicle screw fixation, including 8 cases of lumbar instability, 5 cases of mild to moderate lumbar spondylolisthesis;there were 5 males and 8 females, aged from 56 to 73 years with an average of 62.1 years. All patients were single segment fusion. Operation time, perioperative bleeding and perioperative complications were recorded. Visual analogue scale (VAS) and Oswestry Disability Index (ODI) were used to evaluate the clinical efficacy. Interbody fusion rate was observed and the intervertebral foramen area changes were compared preoperation and postoperation by X-rays and CT scanning. The mean operation time and perioperative bleeding in the patients respectively was(62.8±5.2) min and(82.5±22.6) ml. One case occurred in the numbness of femoribus internus and 1 case occurred in the muscle weakness of hip flexion after operation, both of them recovered within 2 weeks. All the patients were followed up from 12 to 19 months with an average of 15.6 months. VAS was decreased from preoperative 7.31±0.75 to 2.31±0.75 at final follow-up( P degenerative disease.

  2. Trends Analysis of rhBMP2 Utilization in Single-Level Anterior Lumbar Interbody Fusion in the United States.

    Science.gov (United States)

    Lao, Lifeng; Cohen, Jeremiah R; Buser, Zorica; Brodke, Darrel S; Yoon, S Tim; Youssef, Jim A; Park, Jong-Beom; Meisel, Hans-Joerg; Wang, Jeffrey C

    2018-04-01

    Retrospective case study. To evaluate the trends and demographics of recombinant human bone morphogenetic protein 2 (rhBMP2) utilization in single-level anterior lumbar interbody fusion (ALIF) in the United States. Patients who underwent single-level ALIF from 2005 to 2011 were identified by searching ICD-9 diagnosis and procedure codes in the PearlDiver Patient Records Database (PearlDiver Technologies, Fort Wayne, IN), a national database of orthopedic insurance records. The year of procedure, age, gender, and region of the United States were analyzed for each patient. A total of 921 patients were identified who underwent a single-level ALIF in this study. The average rate of single-level ALIF with rhBMP2 utilization increased (35%-48%) from 2005 to 2009, but sharply decreased to 16.7% in 2010 and 15.0% in 2011. The overall incidence of single-level ALIF without rhBMP2 (0.20 cases per 100 000 patients) was more than twice of the incidence of single-level ALIF with rhBMP2 (0.09 cases per 100 000 patients). The average rate of single-level ALIF with rhBMP2 utilization is highest in West (41.4%), followed by Midwest (33.3%), South (26.5%) and Northeast (22.2%). The highest incidence of single-level ALIF with rhBMP2 was observed in the group aged less than 65 years (compared with any other age groups, P level ALIF increased from 2006 to 2009, but decreased in 2010 and 2011. The Northeast region had the lowest incidence of rhBMP2 utilization. The group aged less than 65 years trended to have the higher incidence of single-level ALIF with rhBMP2 utilization.

  3. Perioperative surgical complications and learning curve associated with minimally invasive transforaminal lumbar interbody fusion: a single-institute experience.

    Science.gov (United States)

    Park, Yung; Lee, Soo Bin; Seok, Sang Ok; Jo, Byung Woo; Ha, Joong Won

    2015-03-01

    As surgical complications tend to occur more frequently in the beginning stages of a surgeon's career, knowledge of perioperative complications is important to perform a safe procedure, especially if the surgeon is a novice. We sought to identify and describe perioperative complications and their management in connection with minimally invasive transforaminal lumbar interbody fusion (TLIF). We performed a retrospective chart review of our first 124 patients who underwent minimally invasive TLIF. The primary outcome measure was adverse events during the perioperative period, including neurovascular injury, implant-related complications, and wound infection. Pseudarthroses and adjacent segment pathologies were not included in this review. Adverse events that were not specifically related to spinal surgery and did not affect recovery were also excluded. Perioperative complications occurred in 9% of patients (11/124); including three cases of temporary postoperative neuralgia, two deep wound infections, two pedicle screw misplacements, two cage migrations, one dural tear, and one grafted bone extrusion. No neurologic deficits were reported. Eight complications occurred in the first one-third of the series and only 3 complications occurred in the last two-thirds of the series. Additional surgeries were performed in 6% of patients (7/124); including four reoperations (two for cage migrations, one for a misplaced screw, and one for an extruded graft bone fragment) and three hardware removals (one for a misplaced screw and two for infected cages). We found perioperative complications occurred more often in the early period of a surgeon's experience with minimally invasive TLIF. Implant-related complications were common and successfully managed by additional surgeries in this series. We suggest greater caution should be exercised to avoid the potential complications, especially when surgeon is a novice to this procedure.

  4. R and D into stand-alone PV systems for export

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    The current status of photovoltaic (PV) technology is reviewed for systems to provide electricity where mains supplies are unavailable, known as stand-alone PV systems. Typical applications and experiences with installed stand-alone systems are described. Economic issues and barriers to the wide use of PV systems are also examined. (UK)

  5. Is dibotermin alfa a cost-effective substitute for autologous iliac crest bone graft in single level lumbar interbody spine fusion?

    Science.gov (United States)

    Svedbom, Axel; Paech, Daniel; Leonard, Catherine; Donnell, David; Song, Fujian; Boszcyk, Bronek; Rothenfluh, Dominique A; Lloyd, Andrew; Borgman, Benny

    2015-11-01

    To evaluate the cost-effectiveness of dibotermin alfa compared with autologous iliac crest bone graft (ICBG) for patients undergoing single level lumbar interbody spinal fusion in a UK hospital setting. An individual patient data (IPD) meta-analysis of six randomized controlled clinical trials and two single arm trials compared dibotermin alfa on an absorbable collagen implantation matrix (ACIM) (n = 456) and ICBG (n = 244) on resource use, re-operation rates, and SF-6D (Short form 6-dimension) health utility (total N = 700). Failure-related second surgery, operating time, post-operative hospital stay, and quality-adjusted life years (QALYs) derived from the IPD meta-analysis were included as inputs in an economic evaluation undertaken to assess the cost-effectiveness of dibotermin alfa/ACIM versus ICBG for patients undergoing single level lumbar interbody spinal fusion. A four year time horizon and the United Kingdom (UK) National Health Service (NHS) and Personal Social Services (PSS) perspective was adopted in the base case, with sensitivity analyses performed to gauge parameter uncertainty. In the base case analysis, patients treated using dibotermin alfa/ACIM (12 mg pack) accrued 0.055 incremental QALYs at an incremental cost of £ 737, compared with patients treated with ICBG. This resulted in an incremental cost-effectiveness ratio (ICER) of £ 13,523, indicating that at a willingness-to-pay threshold of £ 20,000, dibotermin alfa/ACIM is a cost-effective intervention relative to ICBG from the NHS and PSS perspective. In a UK hospital setting, dibotermin alfa/ACIM is a cost-effective substitute for ICBG for patients who require lumbar interbody arthrodesis.

  6. AxiaLIF system: minimally invasive device for presacral lumbar interbody spinal fusion

    OpenAIRE

    Block, Jon; Rapp,; Miller,Larry E.

    2011-01-01

    Steven M Rapp1, Larry E Miller2,3, Jon E Block31Michigan Spine Institute, Waterford, MI, USA; 2Miller Scientific Consulting Inc, Biltmore Lake, NC, USA; 3Jon E. Block, Ph.D., Inc., San Francisco, CA, USAAbstract: Lumbar fusion is commonly performed to alleviate chronic low back and leg pain secondary to disc degeneration, spondylolisthesis with or without concomitant lumbar spinal stenosis, or chronic lumbar instability. However, the risk of iatrogenic injury during traditional anterior, post...

  7. Percutaneous transforaminal endoscopic decompression and cageless percutaneous bone graft transforaminal lumbar interbody fusion: A feasibility study

    Directory of Open Access Journals (Sweden)

    Ajay Krishnan

    2018-01-01

    RESULTS: All the outcome measures were significant (P < 0.05 and fusion achieved in all with a mean follow-up period was 39 ± 6.36 months. Operating room time was 250.23 ± 52.90 min (187–327. Postoperative LOH hospital stay was 29.92 ± 4.94 h (24–39. The tolerance score was 2.30 ± 0.85 (1–3. One superficial bone graft site infection resolved with antibiotics. CONCLUSION: It not appealing to be recommendable to general population inspite of it being low cost and with negligible complications. Further research and engineered tools are needed to reduce the operating time.

  8. Medium-term effects of Dynesys dynamic stabilization versus posterior lumbar interbody fusion for treatment of multisegmental lumbar degenerative disease.

    Science.gov (United States)

    Wu, Haiting; Pang, Qingjiang; Jiang, Guoqiang

    2017-10-01

    Objective To compare the medium-term clinical and radiographic outcomes of Dynesys dynamic stabilization and posterior lumbar interbody fusion (PLIF) for treatment of multisegmental lumbar degenerative disease. Methods Fifty-seven patients with multisegmental lumbar degenerative disease underwent Dynesys stabilization (n = 26) or PLIF (n = 31) from December 2008 to February 2010. The mean follow-up period was 50.3 (range, 46-65) months. Clinical outcomes were evaluated using a visual analogue scale (VAS) and the Oswestry disability index (ODI). Radiographic evaluations included disc height and range of motion (ROM) of the operative segments and proximal adjacent segment on lumbar flexion-extension X-rays. The intervertebral disc signal change was defined by magnetic resonance imaging, and disc degeneration was classified by the Pfirrmann grade. Results The clinical outcomes including the VAS score and ODI were significantly improved in both groups at 3 months and the final follow-up, but the difference between the two was not significant. At the final follow-up, the disc height of stabilized segments in both groups was significantly increased; the increase was more notable in the Dynesys than PLIF group. The ROM of stabilized segments at the final follow-up decreased from 6.20° to 2.76° and 6.56° to 0.00° in the Dynesys and PLIF groups, respectively. There was no distinct change in the height of the proximal adjacent segment in the two groups. The ROM of the proximal adjacent segment in both groups increased significantly at the final follow-up; the change was significantly greater in the PLIF than Dynesys group. Only one case of adjacent segment degeneration occurred in the PLIF group, and this patient underwent a second operation. Conclusions Both Dynesys stabilization and PLIF can improve the clinical and radiographic outcomes of multisegmental lumbar degenerative disease. Compared with PLIF, Dynesys stabilization can maintain the mobility of the

  9. Procedures for Determining the Performance of Stand-Alone Photovoltaic Systems; TOPICAL

    International Nuclear Information System (INIS)

    DeBlasio, R.; Durand, S.; Hansen, R.; Hutchinson, P.; Kroposki, B.; McNutt, P.; Rosenthal, A.; Thomas, M.

    1999-01-01

    This document provides the procedures for determining the performance of stand-alone PV systems. The procedures in this document provide a common approach for evaluating whether a given PV system is suitable to perform the function for which it was designed and manufactured to accomplish, and whether it will provide adequate power to run the load. These procedures cover small stand-alone PV systems. They cover complete outdoor system testing. Test results are valid only for the system that is tested

  10. The Influence of Pelvic Incidence and Lumbar Lordosis Mismatch on Development of Symptomatic Adjacent Level Disease Following Single-Level Transforaminal Lumbar Interbody Fusion.

    Science.gov (United States)

    Tempel, Zachary J; Gandhoke, Gurpreet S; Bolinger, Bryan D; Khattar, Nicolas K; Parry, Philip V; Chang, Yue-Fang; Okonkwo, David O; Kanter, Adam S

    2017-06-01

    Annual incidence of symptomatic adjacent level disease (ALD) following lumbar fusion surgery ranges from 0.6% to 3.9% per year. Sagittal malalignment may contribute to the development of ALD. To describe the relationship between pelvic incidence-lumbar lordosis (PI-LL) mismatch and the development of symptomatic ALD requiring revision surgery following single-level transforaminal lumbar interbody fusion for degenerative lumbar spondylosis and/or low-grade spondylolisthesis. All patients who underwent a single-level transforaminal lumbar interbody fusion at either L4/5 or L5/S1 between July 2006 and December 2012 were analyzed for pre- and postoperative spinopelvic parameters. Using univariate and logistic regression analysis, we compared the spinopelvic parameters of those patients who required revision surgery against those patients who did not develop symptomatic ALD. We calculated the predictive value of PI-LL mismatch. One hundred fifty-nine patients met the inclusion criteria. The results noted that, for a 1° increase in PI-LL mismatch (preop and postop), the odds of developing ALD requiring surgery increased by 1.3 and 1.4 fold, respectively, which were statistically significant increases. Based on our analysis, a PI-LL mismatch of >11° had a positive predictive value of 75% for the development of symptomatic ALD requiring revision surgery. A high PI-LL mismatch is strongly associated with the development of symptomatic ALD requiring revision lumbar spine surgery. The development of ALD may represent a global disease process as opposed to a focal condition. Spine surgeons may wish to consider assessment of spinopelvic parameters in the evaluation of degenerative lumbar spine pathology. Copyright © 2017 by the Congress of Neurological Surgeons

  11. Diagnostic method for lumbar foraminal stenosis based on the clinical results of transforaminal lumbar interbody fusion (TLIF). Utility of the foraminal stenosis score

    International Nuclear Information System (INIS)

    Yamada, Katsutaka; Nakamura, Jun-ichiro; Mitsugi, Naoto; Sato, Masatsune; Saito, Tomoyuki

    2010-01-01

    In this study we analyzed 73 cases treated by transforaminal lumbar interbody fusion (TLIF) for lumbar foraminal stenosis or central canal stenosis and foraminal stenosis, and based on the perioperative findings and outcome of treatment, we considered the diagnostic procedure for lumbar foraminal stenosis in the future. In 25 cases (34.2%) cases there was actually no clear perioperative evidence of foraminal stenosis. We compared the preoperative clinical and imaging findings in the group with perioperative findings and the group without perioperative findings performed a multiple logistic regression analysis to identify factors associated with foraminal stenosis. We also calculated the odds ratio for the perioperative findings and proposed a foraminal stenosis scoring system. (author)

  12. Stand-alone photovoltaic systems in the Netherlands. Evaluation of the market introduction

    International Nuclear Information System (INIS)

    Cloin, J.; Van Dijk, A.L.; Westra, C.A.

    1999-08-01

    The policy followed for stand-alone PV systems in the Netherlands is evaluated for the period 1997-1998. The world-wide powerful growth of the PV industry is not being followed by the increase in volume of implemented stand-alone PV systems in the Netherlands. This leads to the question whether the Dutch policy to stimulate stand-alone PV systems is effective. Recommendations on the use of communication as a strategic instrument are given, including the drawing up of a marketing plan. Other recommendations include increased transparency in the application for subsidies and a pro-active role of the Netherlands Agency for Energy and the Environment (Novem) in the contact with relevant market parties. The increased focus on product development aimed at the environmental benefits and general reliability of PV systems is recommended. 38 refs

  13. Stand-alone wind system with Vanadium Redox Battery energy storage

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Barote, L.; Weissbach, R.

    2008-01-01

    Energy storage devices are required for power balance and power quality in stand alone wind energy systems. A Vanadium Redox Flow Battery (VRB) system has many features which make its integration with a stand-alone wind energy system attractive. This paper proposes the integration of a VRB system...... with a typical stand-alone wind energy system during wind speed variation as well as transient performance under variable load. The investigated system consists of a variable speed wind turbine with permanent magnet synchronous generator (PMSG), diode rectifier bridge, buck-boost converter, bidirectional charge...... controller, transformer, inverter, ac loads and VRB (to store a surplus of wind energy and to supply power during a wind power shortage). The main purpose is to supply domestic appliances through a single phase 230V, 50Hz inverter. Simulations are accomplished in order to validate the stability of the supply....

  14. Connecting embedded and stand-alone peer mentoring models to enhance student engagement

    Directory of Open Access Journals (Sweden)

    Rhys Cooper

    2018-03-01

    Full Text Available This paper outlines the Trident Student Mentoring Program that runs in the College of Engineering at Victoria University, Melbourne, Australia. The program offers both embedded and stand-alone models of peer mentoring services to the same cohort of first-year students. It shows that by forming strong links between these two types of peer mentoring models, the inherent challenges of both, such as low attendance rates in stand-alone models and short periods of peer to peer time in embedded models, are mitigated.

  15. Sensorless direct voltage control of the stand-alone brushless doubly-fed generator

    DEFF Research Database (Denmark)

    Liu, Yi; Xu, Wei; Xiong, Fei

    2017-01-01

    The conventional stand-alone brushless doubly-fed generator (BDFG) control strategies need the feedback from the rotor position or speed sensors, which can reduce system reliability and increase the cost and axial volume of the machine. In this paper, a sensorless direct voltage control (DVC) str......) strategy is presented for the stand-alone BDFG. The satisfactory dynamic performance is verified by experimental results under four kinds of typical operation conditions. Besides, the proposed control strategy is robust due to no generator parameters being required....

  16. Linguistic and Structural Analyses of Stand-Alone Literature Reviews: Seventy-Five Years of Change

    Science.gov (United States)

    Wright, Heidi Rachel

    2016-01-01

    The purpose of this dissertation is to offer a multifaceted overview of stand-alone literature reviews. These texts, literature reviews published unattached to research articles, have existed for centuries but remained largely unstudied by linguists. Thus, the goal of this project is to present these reviews' situational, grammatical, and…

  17. Assessment of Stand-Alone Displays for Time Management in a Creativity-Driven Learning Environment

    DEFF Research Database (Denmark)

    Frimodt-Møller, Søren

    2017-01-01

    This paper considers the pros and cons of stand-alone displays, analog (e.g. billboards, blackboards, whiteboards, large pieces of paper etc.) as well as digital (e.g. large shared screens, digital whiteboards or similar), as tools for time management processes in a creativity-driven learning...

  18. Stand-alone version of the 11kW Gaia wind turbine

    DEFF Research Database (Denmark)

    Bindner, H.; Rosas, P.A.C.; Teodorescu, R.

    2004-01-01

    This report describes the development of a stand-alone version of the 11kW Gaia wind turbine. Various possible configurations are investigated and a configuration using a back-to-back converter is chosen. A model is developed for controller design of thefast controllers of the unit. Controllers...... assessment and controller design a dynamic performance assessment model has been developed....

  19. A maximum power point tracking scheme for a 1kw stand-alone ...

    African Journals Online (AJOL)

    A maximum power point tracking scheme for a 1kw stand-alone solar energy based power supply. ... Nigerian Journal of Technology ... A method for efficiently maximizing the output power of a solar panel supplying a load or battery bus under ...

  20. Use of Super-Capacitor to Enhance Charging Performance of Stand-Alone Solar PV System

    KAUST Repository

    Huang, B. J.; Hsu, P. C.; Ho, P. Y

    2011-01-01

    Introduction: The battery charging performance in a stand-alone solar PV system affects the PV system efficiency and the load operating time. The New Energy Center of National Taiwan University has been devoted to the development of a PWM charging

  1. Environmental/Climatic Effect on Stand-Alone Solar Energy Supply ...

    African Journals Online (AJOL)

    This paper investigates the climatic eects and environmental variations on the performance of a stand-alone photovoltaic system. The eects of partial shading with dierent climate conditions and load resistance variations were examined. A survey of some of the work done in this eld of environmental eect on solar panel was ...

  2. 11kW stand alone wind turbine based on proven wind turbine

    DEFF Research Database (Denmark)

    Bindner, H.; Wodstrup, J.; Andersen, J.

    2004-01-01

    and enable control of frequency and voltage independently on both the grid side and the generator side. The prototype has been installed at Risø. The paper will present results from test runs of the system both operating stand-alone supplying a single load and in parallel operation with a diesel genset....

  3. Modelling of fluid-solid interaction using two stand-alone codes

    CSIR Research Space (South Africa)

    Grobler, Jan H

    2010-01-01

    Full Text Available A method is proposed for the modelling of fluid-solid interaction in applications where fluid forces dominate. Data are transferred between two stand-alone codes: a dedicated computational fluid dynamics (CFD) code capable of free surface modelling...

  4. Minimally Invasive Transforaminal Lumbar Interbody Fusion with Percutaneous Bilateral Pedicle Screw Fixation for Lumbosacral Spine Degenerative Diseases. A retrospective database of 40 consecutive treated cases and literature review.

    Science.gov (United States)

    Millimaggi, Daniele Francesco; DI Norcia, Valerio; Luzzi, Sabino; Alfiero, Tommaso; Galzio, Renato Juan; Ricci, Alessandro

    2017-04-12

    To report our results about minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) with bilateral pedicle screw fixation, in patients with degenerative lumbosacral spine disease. To describe the indications, surgical technique and results of a consecutive series of 40 patients undergone MI-TLIF. Despite the limited number of clinical studies, published data suggest tremendous potential advantages of this technique. Forty patients with radiological findings of degenerative lumbosacral spine disease were undergone MI-TLIF between July 2012 and January 2015. Clinical outcomes were assessed by means of Oswestry Disability Index (ODI) and Health Survey Scoring (SF36) before surgery and at first year follow-up. Furthermore, the following parameters were retrospectively reviewed: age, sex, working activity, body mass index (BMI), type of degenerative disease, number of levels of fusion, operative time, blood loss, length of hospital stay. Average operative time was of 230 minutes, mean estimated blood loss 170 mL, average length of hospital stay 5 days. The ODI improved from a score of 59, preoperatively, to post-operative score of 20 at first year follow-up. Average SF36 score increased from 36 to 54 (Physical Health) and from 29 to 50 (Mental Health) at first year outcome evaluation. MI-TLIF with bilateral pedicle screw fixation is an excellent choice for selected patients suffering from symptomatic degenerative lumbosacral spine disease, especially secondary to recurrent disk herniations.

  5. First Results of a New Vacuum Plasma Sprayed (VPS Titanium-Coated Carbon/PEEK Composite Cage for Lumbar Interbody Fusion

    Directory of Open Access Journals (Sweden)

    Sven Hoppe

    2018-03-01

    Full Text Available The aim of this study was to assess the performance of a new vacuum plasma sprayed (VPS titanium-coated carbon/polyetheretherketone (PEEK cage under first use clinical conditions. Forty-two patients who underwent a one or two segment transforaminal lumbar interbody fusion (TLIF procedure with a new Ca/PEEK composite cage between 2012 and 2016 were retrospectively identified by an electronic patient chart review. Fusion rates (using X-ray, patient’s satisfaction, and complications were followed up for two years. A total of 90.4% of the patients were pain-free and satisfied after a follow up (FU period of 29.1 ± 9 (range 24–39 months. A mean increase of 3° in segmental lordosis in the early period (p = 0.002 returned to preoperative levels at final follow-ups. According to the Bridwell classification, the mean 24-month G1 fusion rate was calculated as 93.6% and the G2 as 6.4%. No radiolucency around the cage (G3 or clear pseudarthrosis could be seen (G4. In conclusion, biological properties of the inert, hydrophobic surface, which is the main disadvantage of PEEK, can be improved with VPS titanium coating, so that the carbon/PEEK composite cage, which has great advantages in respect of biomechanical properties, can be used safely in TLIF surgery. High fusion rates, good clinical outcome, and low implant-related complication rates without the need to use rhBMP or additional iliac bone graft can be achieved.

  6. Surgical data and early postoperative outcomes after minimally invasive lumbar interbody fusion: results of a prospective, multicenter, observational data-monitored study.

    Directory of Open Access Journals (Sweden)

    Paulo Pereira

    Full Text Available Minimally invasive lumbar interbody fusion (MILIF offers potential for reduced operative morbidity and earlier recovery compared with open procedures for patients with degenerative lumbar disorders (DLD. Firm conclusions about advantages of MILIF over open procedures cannot be made because of limited number of large studies of MILIF in a real-world setting. Clinical effectiveness of MILIF in a large, unselected real-world patient population was assessed in this Prospective, monitored, international, multicenter, observational study.To observe and document short-term recovery after minimally invasive interbody fusion for DLD.In a predefined 4-week analysis from this study, experienced surgeons (≥ 30 MILIF surgeries pre-study treated patients with DLD by one- or two-level MILIF. The primary study objective was to document patients' short-term post-interventional recovery (primary objective including back/leg pain (visual analog scale [VAS], disability (Oswestry Disability Index [ODI], health status (EQ-5D and Patient satisfaction.At 4 weeks, 249 of 252 patients were remaining in the study; the majority received one-level MILIF (83% and TLIF was the preferred approach (94.8%. For one-level (and two-level procedures, surgery duration was 128 (182 min, fluoroscopy time 115 (154 sec, and blood-loss 164 (233 mL. Time to first ambulation was 1.3 days and time to study-defined surgery recovery was 3.2 days. Patients reported significantly (P < 0.0001 reduced back pain (VAS: 2.9 vs 6.2, leg pain (VAS: 2.5 vs 5.9, and disability (ODI: 34.5% vs 45.5%, and a significantly (P < 0.0001 improved health status (EQ-5D index: 0.61 vs 0.34; EQ VAS: 65.4 vs 52.9 4 weeks postoperatively. One adverse event was classified as related to the minimally invasive surgical approach. No deep site infections or deaths were reported.For experienced surgeons, MILIF for DLD demonstrated early benefits (short time to first ambulation, early recovery, high patient satisfaction

  7. Use of appliances in stand-alone PV power supply systems: problems and solutions. Task 3 use of photovoltaic power systems in stand-alone and island applications

    Energy Technology Data Exchange (ETDEWEB)

    Vallve, X.; Gafas, G. [IEA PVPS, Task 3 (Spain); Villoz, M. [IEA PVPS, Task 3 (Switzerland); Wilshaw, A. [IEA PVPS, Task 3 (United Kingdom); Jacquin, P. [IEA PVPS, Task 3 (France)

    2002-09-15

    In Stand-Alone Photovoltaic Systems (SAPV systems), special attention must be paid to the used appliances and loads. Inappropriate loads are very often the origin of PV system malfunction or failure. Start-up power peaks, or reactive power and harmonic distortion can cause system signal instability and protective devices will close the system down. A well-matched load together with a carefully selected choice of appliances can lead to significant savings in terms of reduced need for PV and electricity storage capacity. Conversely, inefficient appliances and processes, standby loads and inappropriate loads will increase the requirement for expensive PV and storage capacity. This paper presents a survey of real cases with load related problems in worldwide applications, their effect on quality and cost of the service and the solutions that were adopted and suggested alternative solutions. One of the main conclusions of the work is the importance to integrate the choice of the appliance while designing the SAPV system. (author)

  8. Hybrid Configuration of Darrieus and Savonius Rotors for Stand-alone Power Systems

    Science.gov (United States)

    Wakui, Tetsuya; Tanzawa, Yoshiaki; Hashizume, Takumi; Nagao, Toshio

    The suitable hybrid configuration of Darrieus lift-type and Savonius drag-type rotors for stand-alone wind turbine-generator systems is discussed using our dynamic simulation model. Two types of hybrid configurations are taken up: Type-A installs the Savonius rotor inside the Darrieus rotor and Type-B installs the Savonius rotor outside the Darrieus rotor. The computed results of the output characteristics and the dynamic behaviors of the system operated at the maximum power coefficient points show that Type-A, which has fine operating behavior to wind speed changes and can be compactly designed because of a shorter rotational shaft, is an effective way for self-controlled stand-alone small-scale systems.

  9. Stand-Alone Microgrid Inverter Controller Design for Nonlinear, Unbalanced Load with Output Transformer

    Directory of Open Access Journals (Sweden)

    Jae-Uk Lim

    2018-04-01

    Full Text Available This paper proposes a technique that compensates for unbalance and nonlinearity in microgrid inverters with power transformers operating in stand-alone mode. When a microgrid inverter is operating in stand-alone mode, providing high-quality power is very important. When an unbalanced, nonlinear load is connected, zero sequence current and negative sequence current occur, which leads to an unbalanced output voltage. This paper examines why the zero sequence component occurs differently depending on the structure of a three-phase transformer connected to the inverter output terminal, and it proposes a method for controlling the zero sequence component. It also uses a resonant controller to remove the harmonics that correspond to the negative sequence component and the nonlinear component. The proposed elements were verified by a Powersim (PSIM simulation.

  10. A Three-Port Topology Comparison for a Low Power Stand-Alone Photovoltaic System

    DEFF Research Database (Denmark)

    Mira Albert, Maria del Carmen; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    Three-port converter (TPC) topologies for renewable energy systems aim to provide higher efficiency and power density than conventional cascaded structures. This work proposes an analytical comparison of different TPC topologies for a photovoltaic LED lamp stand-alone system. A comparison using c...... component stress factor (CSF) is performed, which gives a quantitative measure of the performance of the converter. The candidate topologies are compared to each other according to a defined LED lighting strategy and a solar irradiation profile.......Three-port converter (TPC) topologies for renewable energy systems aim to provide higher efficiency and power density than conventional cascaded structures. This work proposes an analytical comparison of different TPC topologies for a photovoltaic LED lamp stand-alone system. A comparison using...

  11. Analysis and controller design for stand-alone VSIs in synchronous reference frame

    DEFF Research Database (Denmark)

    Ramezani, Malek; Li, Shuhui; Golestan, Saeed

    2017-01-01

    -by-step graphical analysis and design approach for a three-phase stand-alone VSI system in the dq reference frame, which provides a clear systematic decoupling process to design the inner- and outer-loop current and voltage controllers, respectively. The closed-loop d- and q-axis output impedances of the stand......-alone VSI system by considering the coupling effects between axes are also formulated, modelled, and evaluated. The study investigates how the decoupling and compensating terms added in the current and voltage controllers affect the dynamic performance and output dq impedances of the VSI system. Simulation...... and hardware results verify the effectiveness of the graphic design and analysis strategy....

  12. A new approach for sizing stand alone photovoltaic systems based in neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Hontoria, L.; Aguilera, J. [Universidad de Jaen, Dept. de Electronica, Jaen (Spain); Zufiria, P. [UPM Ciudad Universitaria, Dept. de Matematica Aplicada a las Tecnologias de la Informacion, Madrid (Spain)

    2005-02-01

    Several methods for sizing stand alone photovoltaic (pv) systems has been developed. The more simplistic are called intuitive methods. They are a useful tool for a first approach in sizing stand alone photovoltaic systems. Nevertheless they are very inaccurate. Analytical methods use equations to describe the pv system size as a function of reliability. These ones are more accurate than the previous ones but they are also not accurate enough for sizing of high reliability. In a third group there are methods which use system simulations. These ones are called numerical methods. Many of the analytical methods employ the concept of reliability of the system or the complementary term: loss of load probability (LOLP). In this paper an improvement for obtaining LOLP curves based on the neural network called Multilayer Perceptron (MLP) is presented. A unique MLP for many locations of Spain has been trained and after the training, the MLP is able to generate LOLP curves for any value and location. (Author)

  13. Minimum cost solution of wind–photovoltaic based stand-alone power systems for remote consumers

    International Nuclear Information System (INIS)

    Kaldellis, J.K.; Zafirakis, D.; Kavadias, K.

    2012-01-01

    Renewable energy sources (RES) based stand-alone systems employing either wind or solar power and energy storage comprise a reliable energy alternative, on top of conventional diesel-electric generator sets, commonly used by remote consumers. However, such systems usually imply the need for oversizing and considerable energy storage requirements leading to relatively high costs. On the other hand, hybrid configurations that may exploit both wind and solar potential of a given area may considerably reduce energy storage capacity and improve the economic performance of the system. In this context, an integrated techno-economic methodology for the evaluation of hybrid wind–photovoltaic stand-alone power systems is currently developed, aiming at the designation of optimum configurations for a typical remote consumer, using economic performance criteria. For the problem investigation, the developed evaluation model is applied to four representative areas of the Greek territory with different wind potential characteristics in order to obtain optimum configurations on the basis of minimum initial investment, 10-year and 20-year total cost. According to the results obtained, the proposed solution is favorably compared with all other stand-alone energy alternatives, reflecting the ability of hybrid systems to adjust even in areas where the local RES potential is not necessarily of high quality. - Highlights: ► Wind- and PV-stand alone systems often imply use of extreme battery capacity. ► Hybrid wind–PV systems may reduce energy storage requirements and associated costs. ► An optimization methodology is developed, based on economic performance criteria. ► Methodology is applied to four Greek regions of different wind potential. ► Results obtained reflect the hybrid solution's advantages over other alternatives.

  14. Secure stand alone positive personnel identity verification system (SSA-PPIV)

    International Nuclear Information System (INIS)

    Merillat, P.D.

    1979-03-01

    The properties of a secure stand-alone positive personnel identity verification system are detailed. The system is designed to operate without the aid of a central computing facility and the verification function is performed in the absence of security personnel. Security is primarily achieved by means of data encryption on a magnetic stripe badge. Several operational configurations are discussed. Advantages and disadvantages of this system compared to a central computer driven system are detailed

  15. MOSFET Loss Evaluation for a Low-Power Stand-Alone Photovoltaic-LED System

    DEFF Research Database (Denmark)

    Mira Albert, Maria del Carmen; Knott, Arnold; Andersen, Michael A. E.

    2015-01-01

    This paper presents a performance evaluation and comparison of state-of-the-art low voltage Si MOSFETs for a stand-alone photovoltaic-LED Light to Light (LtL) system. The complete system is formed by two cascaded converters that will be optimized for a determined solar irradiation and LED...... illumination profiles. The comparison is performed based on dynamic characterization and evaluation of the devices energy loss at different current levels....

  16. Stand-Alone Solar Organic Rankine Cycle Water Pumping System and Its Economic Viability in Nepal

    OpenAIRE

    Suresh Baral; Kyung Chun Kim

    2015-01-01

    The current study presents the concept of a stand-alone solar organic Rankine cycle (ORC) water pumping system for rural Nepalese areas. Experimental results for this technology are presented based on a prototype. The economic viability of the system was assessed based on solar radiation data of different Nepalese geographic locations. The mechanical power produced by the solar ORC is coupled with a water pumping system for various applications, such as drinking and irrigation. The thermal ef...

  17. Methodology for the design of a stand-alone photovoltaic power supply

    OpenAIRE

    López Seguel, Julio; Seleme Junior, Seleme Isaac; Donoso-Garcia, Pedro F; Ferreira Morais, Lenin Martins; Cabaleiro Cortizo, Porfirio; Severo Mendes, Marcos A

    2013-01-01

    This paper presents a complete methodology for the design of an autonomous photovoltaic system to maximize the use of solar energy. It is a method that prioritizes the best cost-effective choice at every step of the project. In order to ensure the proper use and extended battery life time, a control strategy for charging the batteries is proposed. Experimental results are provided for a stand-alone photovoltaic system with low electrical power, intended primarily for the illumination and basi...

  18. Effect of Mechanical Ventilation Mode Type on Intra- and Postoperative Blood Loss in Patients Undergoing Posterior Lumbar Interbody Fusion Surgery: A Randomized Controlled Trial.

    Science.gov (United States)

    Kang, Woon-Seok; Oh, Chung-Sik; Kwon, Won-Kyoung; Rhee, Ka Young; Lee, Yun Gu; Kim, Tae-Hoon; Lee, Suk Ha; Kim, Seong-Hyop

    2016-07-01

    The aim of study was to evaluate the effect of mechanical ventilation mode type, pressure-controlled ventilation (PCV), or volume-controlled ventilation (VCV) on intra- and postoperative surgical bleeding in patients undergoing posterior lumbar interbody fusion (PLIF) surgery. This was a prospective, randomized, single-blinded, and parallel study that included 56 patients undergoing PLIF and who were mechanically ventilated using PCV or VCV. A permuted block randomization was used with a computer-generated list. The hemodynamic and respiratory parameters were measured after anesthesia induction in supine position, 5 min after patients were changed from supine to prone position, at the time of skin closure, and 5 min after the patients were changed from prone to supine position. The amount of intraoperative surgical bleeding, fluid administration, urine output, and transfusion requirement were measured at the end of surgery. The amount of postoperative bleeding and transfusion requirement were recorded every 24 h for 72 h. The primary outcome was the amount of intraoperative surgical bleeding, and 56 patients were analyzed. The amount of intraoperative surgical bleeding was significantly less in the PCV group than that in the VCV group (median, 253.0 [interquartile range, 179.0 to 316.5] ml in PCV group vs. 382.5 [328.0 to 489.5] ml in VCV group; P patients undergoing PLIF, which may be related to lower intraoperative peak inspiratory pressure.

  19. Modeling, Design and Simulation of Stand-Alone Photovoltaic Power Systems with Battery Storage

    Directory of Open Access Journals (Sweden)

    Abd Essalam BADOUD

    2013-06-01

    Full Text Available Stand alone renewable energy based on photovoltaic systems accompanied with battery storage system are beginning to play an important role over the world to supply power to remote areas. The objective of the study reported in this paper is to elaborate and design a bond graphs model for sizing stand-alone domestic solar photovoltaic electricity systems and simulating the performance of the systems in a tropical climate. The systems modelled consist of an array of PV modules, a lead-acid battery, and a number of direct current appliances. This paper proposes the combination of lead acid battery system with a typical stand alone photovoltaic energy system under variable loads. The main activities of this work purpose to establish library graphical models for each individual component of standalone photovoltaic system. Control strategy has been considered to achieve permanent power supply to the load via photovoltaic/battery based on the power available from the sun. The complete model was simulated under two testing including sunny and cloudy conditions. Simulation of the system using Symbols software was performed and the results of simulation show the superior stable control system and high efficiency. These results have been contrasted with real measured data from a measurement campaign plant carried on electrical engineering laboratory of Grenoble using various interconnection schemes are presented.

  20. Structure Optimization of Stand-Alone Renewable Power Systems Based on Multi Object Function

    Directory of Open Access Journals (Sweden)

    Jae-Hoon Cho

    2016-08-01

    Full Text Available This paper presents a methodology for the size optimization of a stand-alone hybrid PV/wind/diesel/battery system while considering the following factors: total annual cost (TAC, loss of power supply probability (LPSP, and the fuel cost of the diesel generator required by the user. A new optimization algorithm and an object function (including a penalty method are also proposed; these assist with designing the best structure for a hybrid system satisfying the constraints. In hybrid energy system sources such as photovoltaic (PV, wind, diesel, and energy storage devices are connected as an electrical load supply. Because the power produced by PV and wind turbine sources is dependent on the variation of the resources (sun and wind and the load demand fluctuates, such a hybrid system must be able to satisfy the load requirements at any time and store the excess energy for use in deficit conditions. Therefore, reliability and cost are the two main criteria when designing a stand-alone hybrid system. Moreover, the operation of a diesel generator is important to achieve greater reliability. In this paper, TAC, LPSP, and the fuel cost of the diesel generator are considered as the objective variables and a hybrid teaching–learning-based optimization algorithm is proposed and used to choose the best structure of a stand-alone hybrid PV/wind/diesel/battery system. Simulation results from MATLAB support the effectiveness of the proposed method and confirm that it is more efficient than conventional methods.

  1. Effect of Interbody Fusion on the Remaining Discs of the Lumbar Spine in Subjects with Disc Degeneration.

    Science.gov (United States)

    Ryu, Robert; Techy, Fernando; Varadarajan, Ravikumar; Amirouche, Farid

    2016-02-01

    To study effects (stress loads) of lumbar fusion on the remaining segments (adjacent or not) of the lumbar spine in the setting of degenerated adjacent discs. A lumbar spine finite element model was built and validated. The full model of the lumbar spine was a parametric finite element model of segments L 1-5 . Numerous hypothetical combinations of one-level lumbar spine fusion and one-level disc degeneration were created. These models were subjected to 10 Nm flexion and extension moments and the stresses on the endplates and consequently on the intervertebral lumbar discs measured. These values were compared to the stresses on healthy lumbar spine discs under the same load and fusion scenarios. Increased stress at endplates was observed only in the settings of L4-5 fusion and L3-4 disc degeneration (8% stress elevation at L2,3 in flexion or extension, and 25% elevation at L3,4 in flexion only). All other combinations showed less endplate stress than did the control model. For fusion at L3-4 and degeneration at L4-5 , the stresses in the endplates at the adjacent level inferior to the fused disc decreased for both loading disc height reductions. Stresses in flexion decreased after fusion by 29.5% and 25.8% for degeneration I and II, respectively. Results for extension were similar. For fusion at L2-3 and degeneration at L4-5 , stresses in the endplates decreased more markedly at the degenerated (30%), than at the fused level (14%) in the presence of 25% disc height reduction and 10 Nm flexion, whereas in extension stresses decreased more at the fused (24.3%) than the degenerated level (5.86%). For fusion at L3-4 and degeneration at L2-3 , there were no increases in endplate stress in any scenario. For fusion at L4-5 and degeneration at L3-4 , progression of degeneration from I to II had a significant effect only in flexion. A dramatic increase in stress was noted in the endplates of the degenerated disc (L3-4 ) in flexion for degeneration II. Stresses are greater

  2. Optimization of stand-alone photovoltaic systems with hydrogen storage for total energy self-sufficiency

    Energy Technology Data Exchange (ETDEWEB)

    Lund, P D [Helsinki Univ. of Technology, Espoo (Finland). Dept. of Technical Physics

    1991-01-01

    A new method for optimization of stand-alone photovoltaic-hydrogen energy systems is presented. The methodology gives the optimum values for the solar array and hydrogen storage size for any given system configuration and geographical site. Sensitivity analyses have been performed to study the effect of subsystem efficiencies on the total system performance and sizing, and also to identify possibilities for further improvements. Optimum system configurations have also been derived. The results indicate that a solar-hydrogen energy system is a very promising potential alternative for low power applications requiring a total electricity self-sufficiency. (Author).

  3. A Simple Sizing Algorithm for Stand-Alone PV/Wind/Battery Hybrid Microgrids

    Directory of Open Access Journals (Sweden)

    Jing Li

    2012-12-01

    Full Text Available In this paper, we develop a simple algorithm to determine the required number of generating units of wind-turbine generator and photovoltaic array, and the associated storage capacity for stand-alone hybrid microgrid. The algorithm is based on the observation that the state of charge of battery should be periodically invariant. The optimal sizing of hybrid microgrid is given in the sense that the life cycle cost of system is minimized while the given load power demand can be satisfied without load rejection. We also report a case study to show the efficacy of the developed algorithm.

  4. Lossy Data Aggregation with Network Coding in Stand-Alone Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Madsen, Tatiana Kozlova

    2011-01-01

    in chemical plants, etc. Given resource constrained operation of a sensor network where the nodes are battery powered and buffer sizes are limited, efficient methods for in-network data storage abd it subsequent fast and reliable transmission to a gateway is desirable. To save scarse resources and to prolong......This work focuses on a special type of wireless sensor networks (WSNs) that we refer to as a stand alone network. These netwoks operate in harsh and extreme environments where data collection is done only occasionally. Typical examples include habitat monitoring systems, monitoring systems...

  5. Boost converter with combined control loop for a stand-alone photovoltaic battery charge system

    DEFF Research Database (Denmark)

    Mira Albert, Maria del Carmen; Knott, Arnold; Thomsen, Ole Cornelius

    2013-01-01

    frequency avoids perturbations in the load being propagated to the photovoltaic panel and thus deviating the operating point. Linearization of the photovoltaic panel and converter state-space modeling is performed. In order to achieve stable operation under all operating conditions, the photovoltaic panel......The converter control scheme plays an important role in the performance of maximum power point tracking (MPPT) algorithms. In this paper, an input voltage control with double loop for a stand-alone photovoltaic system is designed and tested. The inner current control loop with high crossover...

  6. System design optimization for stand-alone photovoltaic systems sizing by using superstructure model

    International Nuclear Information System (INIS)

    Azau, M A M; Jaafar, S; Samsudin, K

    2013-01-01

    Although the photovoltaic (PV) systems have been increasingly installed as an alternative and renewable green power generation, the initial set up cost, maintenance cost and equipment mismatch are some of the key issues that slows down the installation in small household. This paper presents the design optimization of stand-alone photovoltaic systems using superstructure model where all possible types of technology of the equipment are captured and life cycle cost analysis is formulated as a mixed integer programming (MIP). A model for investment planning of power generation and long-term decision model are developed in order to help the system engineer to build a cost effective system.

  7. Development of a microprocessor controller for stand-alone photovoltaic power systems

    Science.gov (United States)

    Millner, A. R.; Kaufman, D. L.

    1984-01-01

    A controller for stand-alone photovoltaic systems has been developed using a low power CMOS microprocessor. It performs battery state of charge estimation, array control, load management, instrumentation, automatic testing, and communications functions. Array control options are sequential subarray switching and maximum power control. A calculator keypad and LCD display provides manual control, fault diagnosis and digital multimeter functions. An RS-232 port provides data logging or remote control capability. A prototype 5 kW unit has been built and tested successfully. The controller is expected to be useful in village photovoltaic power systems, large solar water pumping installations, and other battery management applications.

  8. Design, building and testing of a stand alone fuel cell hybrid system

    Energy Technology Data Exchange (ETDEWEB)

    Segura, F.; Duran, E.; Andujar, J.M. [Department of Electronic, Computer Science and Automatic Engineering, University of Huelva (Spain)

    2009-08-01

    This paper designs, sizes, builds and tests a stand alone fuel cell hybrid system made up of a fuel cell stack and a battery bank. This system has been sized to supply a typical telecommunication load profile, but moreover, the system can supply other profiles. For this purpose, a modular low cost electronic load bank has been designed and built. This load bank allows the power demand to be chosen by selecting different solid state relays. Moreover, a virtual instrument based on NI Labview {sup registered} has been designed to select the load power demand from the computer. (author)

  9. Design and Operation Studies of A Stand-Alone PV Generation System

    DEFF Research Database (Denmark)

    Hu, Yanting; Chen, Zhe; Zhang, Donglai

    2013-01-01

    This paper discusses the modeling, design and operation of a PV powered stand-alone system, which includes a PV array, a battery bank, power electronic converters and the associated control system. The design considerations are analyzed and a design platform is presented. Furthermore the operation...... modes of the system are described. A power electronic system with the associated control scheme has been proposed and simulation models have been developed. Simulation studies have been conducted on an example system; the results have demonstrated the effectiveness of the presented methods....

  10. State Feedback Decoupling with In-Loop Lead Compensator in Stand-Alone VSIs

    DEFF Research Database (Denmark)

    Federico, de Bosio; Pastorelli, Michele; de Sousa Ribeiro, Luiz Antonio

    2016-01-01

    The performance of current and voltage regulators during transients and steady-state is of primary concern for power converters intended for stand-alone applications. Dynamics performance and command tracking capability are enhanced by actively decoupling the controlled states variables. To further...... widen the current loop bandwidth while still preserving a well-damped system a lead compensator structure on the forward loop is proposed. A 3 kHz bandwidth with 0.707 damping factor is achieved for the inner current controller. Accordingly, also the voltage regulator bandwidth can be widen, thus...

  11. Information systems for the materials management department: stand-alone and enterprise resource planning systems.

    Science.gov (United States)

    2005-03-01

    Materials management information systems (MMISs) incorporate information tools that hospitals can use to automate certain business processes, increase staff compliance with these processes, and identify opportunities for cost savings. Recently, there has been a push by hospital administration to purchase enterprise resource planning (ERP) systems, information systems that promise to integrate many more facets of healthcare business. We offer this article to help materials managers, administrators, and others involved with information system selection understand the changes that have taken place in materials management information systems, decide whether they need a new system and, if so, whether a stand-alone MMIS or an ERP system will be the best choice.

  12. Restoration of lumbopelvic sagittal alignment and its maintenance following transforaminal lumbar interbody fusion (TLIF): comparison between straight type versus curvilinear type cage.

    Science.gov (United States)

    Kim, Jong-Tae; Shin, Myung-Hoon; Lee, Ho-Jin; Choi, Du-Yong

    2015-11-01

    To evaluate a radiological and clinical difference between the curvilinear type cages compared to the straight type cages for the restoration of lumbopelvic sagittal alignment and its maintenance after transforaminal lumbar interbody fusion (TLIF) procedure. 68 patients who underwent single-level TLIF using either the straight type or curvilinear type cage were retrospectively reviewed. Assessment of the lumbopelvic parameters and the height of disc space was performed before surgery as well as 2 days, 6 and 12 months after surgery. Clinical outcome was assessed using VAS and ODI. The curvilinear type cages were positioned more anteriorly than the straight type. Restoration of the segmental lordosis (SL) in the curvilinear group was significantly greater than the straight group and at 12 months of follow-up, the straight group showed greater decrease in the disc height than the curvilinear group. The straight group failed to show improvement of lumbar lordosis (LL), while the curvilinear group showed significant restoration of LL and could maintain it to the 6 months of follow-up. In both groups, pelvic tilt was significantly decreased and it lasted to 6 months in the straight group; whereas in the curvilinear group, it was maintained to the last follow-up of 12 months. There were no significant differences between the two groups in mean VAS and ODI score over the follow-up period. This study demonstrates that the curvilinear type cage is superior to the straight type cage in improving the SL and maintaining both the restored lumbopelvic parameters and elevated disc height. These results could be attributable to the anterior position of the curvilinear cage which permits easy restoration of segmental lordosis and less sinking of cages.

  13. The effectiveness of low-dose and high-dose tranexamic acid in posterior lumbar interbody fusion: a double-blinded, placebo-controlled randomized study.

    Science.gov (United States)

    Kim, Ki-Tack; Kim, Cheung-Kue; Kim, Yong-Chan; Juh, Hyung-Suk; Kim, Hyo-Jong; Kim, Hyeon-Soo; Hong, Se Jung; Hey, Hwee Weng Dennis

    2017-11-01

    Tranexamic acid is a proven drug used for reduction of intraoperative blood loss in spinal surgery. However, optimal dosing considering risk/benefits is not well established owing to the heterogeneity in patient selection and surgical procedures of previous studies. This study aimed to evaluate the effectiveness and safety of various tranexamic acid regimens in reducing perioperative blood loss in single-level posterior lumbar interbody fusion (PLIF). Patients were randomly grouped into three different interventions: low-dose tranexamic acid (LD), high-dose tranexamic acid (HD), and placebo-controlled (PC) groups. The HD and LD groups received 10 and 5 mg/kg of bolus loading dose and 2 and 1 mg/kg of continuous infusion until 5 h after surgery, respectively. Data on patient demographics and preoperative and 24-h postoperative laboratory values were collected. Outcome parameters include intraoperative blood loss, 24-h postoperative blood loss, and blood loss during removal of the last drain. Seventy-two patients (mean age 63.3 ± 7.6 years) showed similar baseline characteristics. Intraoperatively, blood loss was reduced by the administration of tranexamic acid (P = 0.04), contributed predominantly by a difference between the LD and HD groups (123 mL; P tranexamic acid use were noted. Tranexamic acid administration for single-level PLIF was effective and safe in reducing perioperative blood loss in a dose-dependent manner. An HD regimen comprising 10 mg/kg of bolus loading dose and 2 mg/kg/h of continuous infusion is recommended. Level 1 study according to Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence.

  14. Thirty-Day Readmission Risk Factors Following Single-Level Transforaminal Lumbar Interbody Fusion (TLIF) for 4992 Patients From the ACS-NSQIP Database.

    Science.gov (United States)

    Garcia, Roxanna M; Khanna, Ryan; Dahdaleh, Nader S; Cybulski, George; Lam, Sandi; Smith, Zachary A

    2017-05-01

    Retrospective cohort study. To describe the readmission rate and identify risk factors associated with 30-day readmission after transforaminal lumbar interbody fusion (TLIF) surgery. Patients who underwent elective single level TLIF surgery from 2011 to 2013 were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. Emergency or trauma cases were excluded. Preoperative, intraoperative, and postoperative variables were extracted. A multivariate binary regression identified predictors correlated with 30-day readmission. A total of 4992 patients were included in the analysis. The overall 30-day readmission rate was 5.51% (275/4992) for readmissions reported between 2011 to 2013. The mean age of patients readmitted was 62.40 years (standard error [SE] = 0.78) and 60.92 years (SE = 0.20) among those whom were not readmitted ( P = .05). The top three causes for readmission included postoperative pain control, deep or superficial surgical site infections. Predictors associated with 30-day readmission in a multivariate analysis included female gender (odds ratio [OR] = 1.27, 95% CI = 0.97-1.65), history of severe chronic obstructive pulmonary disease (OR = 1.81, 95% CI = 1.11-2.96), and in the postoperative period, American Society of Anesthesiologists class (OR = 1.30, 95% CI = 1.04-1.63), presence of superficial surgical site infection (OR= 18.23, 95% CI = 10.36-32.08), or urinary tract infection (OR = 4.93, 95% CI = 2.84-8.58). The readmission rate, risk factors, and causes following TLIF surgery are comparable to other lumbar spinal procedures reported from the ACS-NSQIP database.

  15. Simulation of stand alone PV systems; Dokuritsugata taiyoko hatsuden system no simulation

    Energy Technology Data Exchange (ETDEWEB)

    Tsuda, I.; Sakuta, K. [Electrotechnical Laboratory, Tsukuba (Japan); Oshiro, T. [Japan Quality Assurance Organization, Tokyo (Japan); Kurokawa, K. [Tokyo University of Agriculture and Technology, Tokyo (Japan)

    1997-11-25

    Studies are performed to develop a simulation program for a stand-alone photovoltaic power generation system equipped with a lead acid battery. In this stand-alone photovoltaic power generation system, the load is connected in shunt with the solar cell array output through the intermediary of a lead acid battery and inverter. The program is a model in which the solar cell model is built taking parallel resistance into account, and the temperature-dependence of the constants is described using approximations experimentally obtained by Solar Techno Center of JQA (Japan Quality Assurance Organization), Hamamatsu. Insolation data for the model is described using METPV compiled by Japan Weather Association, and load data is described using data actually measured at Shizuoka. This program is compared with the data of operation at Hamamatsu, and the result is almost satisfactory. Simulations are conducted at five typical locations in Japan using this program, and it is found that the array load matching correction factor is dependent on seasonal changes rather than locality, that the battery contribution rate does not change much throughout the year, and that it is not dependent on locality. 5 refs., 7 figs., 3 tabs.

  16. Modified Chaos Particle Swarm Optimization-Based Optimized Operation Model for Stand-Alone CCHP Microgrid

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2017-07-01

    Full Text Available The optimized dispatch of different distributed generations (DGs in stand-alone microgrid (MG is of great significance to the operation’s reliability and economy, especially for energy crisis and environmental pollution. Based on controllable load (CL and combined cooling-heating-power (CCHP model of micro-gas turbine (MT, a multi-objective optimization model with relevant constraints to optimize the generation cost, load cut compensation and environmental benefit is proposed in this paper. The MG studied in this paper consists of photovoltaic (PV, wind turbine (WT, fuel cell (FC, diesel engine (DE, MT and energy storage (ES. Four typical scenarios were designed according to different day types (work day or weekend and weather conditions (sunny or rainy in view of the uncertainty of renewable energy in variable situations and load fluctuation. A modified dispatch strategy for CCHP is presented to further improve the operation economy without reducing the consumers’ comfort feeling. Chaotic optimization and elite retention strategy are introduced into basic particle swarm optimization (PSO to propose modified chaos particle swarm optimization (MCPSO whose search capability and convergence speed are improved greatly. Simulation results validate the correctness of the proposed model and the effectiveness of MCPSO algorithm in the optimized operation application of stand-alone MG.

  17. Design of a Stand-Alone Photovoltaic Model for Home Lightings and Clean Environment

    Energy Technology Data Exchange (ETDEWEB)

    Ani, Vincent Anayochukwu, E-mail: vincent_ani@yahoo.com [Department of Electronic Engineering, University of Nigeria, Nsukka (Nigeria)

    2016-01-11

    This paper gives a well-documented health risk of fuel-based lighting (kerosene lamps and fuel-powered generators) and proposed a design of a stand-alone solar PV system for sustainable home lightings in rural Nigerian area. The design was done in three different patterns of electricity consumptions with energy efficient lightings (EELs) using two different battery types (Rolls Surrette 6CS25PS and Hoppecke 10 OpzS 1000) on; (i) judicious power consumption, (ii) normal power consumption, and (iii) excess power consumption; and compared them with the incandescent light bulb consumption. The stand-alone photovoltaic energy systems were designed to match the rural Nigerian sunlight and weather conditions to meet the required lightings of the household. The objective function and constraints for the design models were formulated and optimization procedures were used to demonstrate the best solution (reliability at the lowest lifecycle cost). Initial capital costs as well as annualized costs over 5, 10, 15, 20, and 25 years were quantified and documented. The design identified the most cost-effective and reliable solar and battery array among the patterns of electricity consumption with EEL options (judicious power consumption, normal power consumption, and excess power consumption).

  18. Design of Stand-Alone Hybrid Power Generation System at Brumbun Beach Tulungagung East Java

    Science.gov (United States)

    Rahmat, A. N.; Hidayat, M. N.; Ronilaya, F.; Setiawan, A.

    2018-04-01

    Indonesian government insists to optimize the use of renewable energy resources in electricity generation. One of the efforts is launching Independent Energy Village plan. This program aims to fulfill the need of electricity for isolated or remote villages in Indonesia. In order to support the penetration of renewable energy resources in electricity generation, a hybrid power generation system is developed. The simulation in this research is based on the availability of renewable energy resources in Brumbun beach, Tulungagung, East Java. Initially, the electricity was supplied through stand-alone electricity generations which are installed at each house. Hence, the use of electricity between 5 p.m. – 9 p.m. requires high operational costs. Based on the problem above, this research is conducted to design a stand-alone hybrid electricity generation system, which may consist of diesel, wind, and photovoltaic. The design is done by using HOMER software to optimize the use of electricity from renewable resources and to reduce the operation of diesel generation. The combination of renewable energy resources in electricity generation resulted in NPC of 44.680, COE of 0,268, and CO2 emissions of 0,038 % much lower than the use of diesel generator only.

  19. Fuzzy logic control of stand-alone photovoltaic system with battery storage

    Science.gov (United States)

    Lalouni, S.; Rekioua, D.; Rekioua, T.; Matagne, E.

    Photovoltaic energy has nowadays an increased importance in electrical power applications, since it is considered as an essentially inexhaustible and broadly available energy resource. However, the output power provided via the photovoltaic conversion process depends on solar irradiation and temperature. Therefore, to maximize the efficiency of the photovoltaic energy system, it is necessary to track the maximum power point of the PV array. The present paper proposes a maximum power point tracker (MPPT) method, based on fuzzy logic controller (FLC), applied to a stand-alone photovoltaic system. It uses a sampling measure of the PV array power and voltage then determines an optimal increment required to have the optimal operating voltage which permits maximum power tracking. This method carries high accuracy around the optimum point when compared to the conventional one. The stand-alone photovoltaic system used in this paper includes two bi-directional DC/DC converters and a lead-acid battery bank to overcome the scare periods. One converter works as an MPP tracker, while the other regulates the batteries state of charge and compensates the power deficit to provide a continuous delivery of energy to the load. The Obtained simulation results show the effectiveness of the proposed fuzzy logic controller.

  20. A sizing method for stand-alone PV installations with variable demand

    Energy Technology Data Exchange (ETDEWEB)

    Posadillo, R. [Grupo de Investigacion en Energias y Recursos Renovables, Dpto. de Fisica Aplicada, E.P.S., Universidad de Cordoba, Avda. Menendez Pidal s/n, 14004 Cordoba (Spain); Lopez Luque, R. [Grupo de Investigacion de Fisica Para las Energias y Recursos Renovables, Dpto. de Fisica Aplicada, Edificio C2 Campus de Rabanales, 14071 Cordoba (Spain)

    2008-05-15

    The practical applicability of the considerations made in a previous paper to characterize energy balances in stand-alone photovoltaic systems (SAPV) is presented. Given that energy balances were characterized based on monthly estimations, the method is appropriate for sizing installations with variable monthly demands and variable monthly panel tilt (for seasonal estimations). The method presented is original in that it is the only method proposed for this type of demand. The method is based on the rational utilization of daily solar radiation distribution functions. When exact mathematical expressions are not available, approximate empirical expressions can be used. The more precise the statistical characterization of the solar radiation on the receiver module, the more precise the sizing method given that the characterization will solely depend on the distribution function of the daily global irradiation on the tilted surface H{sub g{beta}}{sub i}. This method, like previous ones, uses the concept of loss of load probability (LLP) as a parameter to characterize system design and includes information on the standard deviation of this parameter ({sigma}{sub LLP}) as well as two new parameters: annual number of system failures (f) and the standard deviation of annual number of system failures ({sigma}{sub f}). This paper therefore provides an analytical method for evaluating and sizing stand-alone PV systems with variable monthly demand and panel inclination. The sizing method has also been applied in a practical manner. (author)

  1. Design of a Stand-Alone Photovoltaic (PV Models for Home Lightings and Clean Environment

    Directory of Open Access Journals (Sweden)

    Vincent Anayochukwu Ani

    2016-01-01

    Full Text Available This paper gives a well-documented health risks of fuel-based lighting (kerosene lamps and fuel-powered generators and proposed a design of a stand-alone solar PV system for sustainable home lightings in rural Nigerian area. The design was done in three different patterns of electricity consumptions with energy efficient lightings (EELs using two different battery types (Rolls Surrette 6CS25PS and hoppecke 10 OpzS 1000 on; i judicious power consumption, ii normal power consumption, iii excess power consumption; and compared them with the incandescent light bulb consumption. The stand-alone photovoltaic energy systems were designed to match the rural Nigerian sunlight and weather conditions to meet the required lightings of the household. The objective function and constraints for the design models were formulated and optimization procedure were used to demonstrate the best solution (reliability at the lowest lifecycle cost. Initial capital costs as well as annualized costs over 5, 10, 15, 20, and 25 years were quantified and documented. The design identified the most cost-effective and reliable solar and battery array among the patterns of electricity consumption with energy efficient lighting options (judicious power consumption, normal power consumption, and excess power consumption.

  2. International market assessment of stand-alone photovoltaic power systems for cottage industry applications

    Science.gov (United States)

    Philippi, T. M.

    1981-01-01

    The final result of an international assessment of the market for stand-alone photovoltaic systems in cottage industry applications is reported. Nonindustrialized countries without centrally planned economies were considered. Cottage industries were defined as small rural manufacturers, employing less than 50 people, producing consumer and simple products. The data to support this analysis were obtained from secondary and expert sources in the U.S. and in-country field investigations of the Philippines and Mexico. The near-term market for photovoltaics for rural cottage industry applications appears to be limited to demonstration projects and pilot programs, based on an in-depth study of the nature of cottage industry, its role in the rural economy, the electric energy requirements of cottage industry, and a financial analysis of stand-alone photovoltaic systems as compared to their most viable competitor, diesel driven generators. Photovoltaics are shown to be a better long-term option only for very low power requirements. Some of these uses would include clay mixers, grinders, centrifuges, lathes, power saws and lighting of a workshop.

  3. Coordination Control Strategy for AC/DC Hybrid Microgrids in Stand-Alone Mode

    Directory of Open Access Journals (Sweden)

    Dwi Riana Aryani

    2016-06-01

    Full Text Available Interest in DC microgrids is rapidly increasing along with the improvement of DC power technology because of its advantages. To support the integration process of DC microgrids with the existing AC utility grids, the form of hybrid AC/DC microgrids is considered for higher power conversion efficiency, lower component cost and better power quality. In the system, AC and DC portions are connected through interlink bidirectional AC/DC converters (IC with a proper control system and power management. In the stand-alone operation mode of AC/DC hybrid microgrids, the control of power injection through the IC is crucial in order to maintain the system security. This paper mainly deals with a coordination control strategy of IC and a battery energy storage system (BESS converter under stand-alone operation. A coordinated control strategy for the IC, which considers the state of charge (SOC level of BESS and the load shedding scheme as the last resort, is proposed to obtain better power sharing between AC and DC subgrids. The scheme will be tested with a hybrid AC/DC microgrid, using the tool of the PSCAD/EMTDC software.

  4. International market assessment of stand-alone photovoltaic power systems for cottage industry applications

    Science.gov (United States)

    Philippi, T. M.

    1981-11-01

    The final result of an international assessment of the market for stand-alone photovoltaic systems in cottage industry applications is reported. Nonindustrialized countries without centrally planned economies were considered. Cottage industries were defined as small rural manufacturers, employing less than 50 people, producing consumer and simple products. The data to support this analysis were obtained from secondary and expert sources in the U.S. and in-country field investigations of the Philippines and Mexico. The near-term market for photovoltaics for rural cottage industry applications appears to be limited to demonstration projects and pilot programs, based on an in-depth study of the nature of cottage industry, its role in the rural economy, the electric energy requirements of cottage industry, and a financial analysis of stand-alone photovoltaic systems as compared to their most viable competitor, diesel driven generators. Photovoltaics are shown to be a better long-term option only for very low power requirements. Some of these uses would include clay mixers, grinders, centrifuges, lathes, power saws and lighting of a workshop.

  5. Feasibility and Optimal Design of a Stand-Alone Photovoltaic Energy System for the Orphanage

    Directory of Open Access Journals (Sweden)

    Vincent Anayochukwu Ani

    2014-01-01

    Full Text Available Access to electricity can have a positive psychological impact through a lessening of the sense of exclusion, and vulnerability often felt by the orphanages. This paper presented the simulation and optimization study of a stand-alone photovoltaic power system that produced the desired power needs of an orphanage. Solar resources for the design of the system were obtained from the National Aeronautics and Space Administration (NASA Surface Meteorology and Solar Energy website at a location of 6°51′N latitude and 7°35′E longitude, with annual average solar radiation of 4.92 kWh/m2/d. This study is based on modeling, simulation, and optimization of energy system in the orphanage. The patterns of load consumption within the orphanage were studied and suitably modeled for optimization. Hybrid Optimization Model for Electric Renewables (HOMER software was used to analyze and design the proposed stand-alone photovoltaic power system model. The model was designed to provide an optimal system configuration based on an hour-by-hour data for energy availability and demands. A detailed design, description, and expected performance of the system were presented in this paper.

  6. Robust Power Management Control for Stand-Alone Hybrid Power Generation System

    International Nuclear Information System (INIS)

    Kamal, Elkhatib; Adouane, Lounis; Aitouche, Abdel; Mohammed, Walaa

    2017-01-01

    This paper presents a new robust fuzzy control of energy management strategy for the stand-alone hybrid power systems. It consists of two levels named centralized fuzzy supervisory control which generates the power references for each decentralized robust fuzzy control. Hybrid power systems comprises: a photovoltaic panel and wind turbine as renewable sources, a micro turbine generator and a battery storage system. The proposed control strategy is able to satisfy the load requirements based on a fuzzy supervisor controller and manage power flows between the different energy sources and the storage unit by respecting the state of charge and the variation of wind speed and irradiance. Centralized controller is designed based on If-Then fuzzy rules to manage and optimize the hybrid power system production by generating the reference power for photovoltaic panel and wind turbine. Decentralized controller is based on the Takagi-Sugeno fuzzy model and permits us to stabilize each photovoltaic panel and wind turbine in presence of disturbances and parametric uncertainties and to optimize the tracking reference which is given by the centralized controller level. The sufficient conditions stability are formulated in the format of linear matrix inequalities using the Lyapunov stability theory. The effectiveness of the proposed Strategy is finally demonstrated through a SAHPS (stand-alone hybrid power systems) to illustrate the effectiveness of the overall proposed method. (paper)

  7. Design of a Stand-Alone Photovoltaic Model for Home Lightings and Clean Environment

    International Nuclear Information System (INIS)

    Ani, Vincent Anayochukwu

    2016-01-01

    This paper gives a well-documented health risk of fuel-based lighting (kerosene lamps and fuel-powered generators) and proposed a design of a stand-alone solar PV system for sustainable home lightings in rural Nigerian area. The design was done in three different patterns of electricity consumptions with energy efficient lightings (EELs) using two different battery types (Rolls Surrette 6CS25PS and Hoppecke 10 OpzS 1000) on; (i) judicious power consumption, (ii) normal power consumption, and (iii) excess power consumption; and compared them with the incandescent light bulb consumption. The stand-alone photovoltaic energy systems were designed to match the rural Nigerian sunlight and weather conditions to meet the required lightings of the household. The objective function and constraints for the design models were formulated and optimization procedures were used to demonstrate the best solution (reliability at the lowest lifecycle cost). Initial capital costs as well as annualized costs over 5, 10, 15, 20, and 25 years were quantified and documented. The design identified the most cost-effective and reliable solar and battery array among the patterns of electricity consumption with EEL options (judicious power consumption, normal power consumption, and excess power consumption).

  8. Input of biomass in stand-alone small-scale installations for power generation. Calculation of the financial gap

    International Nuclear Information System (INIS)

    Van Tilburg, X.; De Vries, H.J.; Pfeiffer, A.E.; Beekes, M.; Cleijne, J.W.

    2005-09-01

    A number of new initiatives in which bio-oil is used in stand-alone plants for power generation has been reviewed. The question to be answered is whether the reference case for stand alone biomass projects based on burning of wood chips can still be considered representative for the costs and benefits in this category. ECN, in cooperation with KEMA, have determined the financial gap between the costs and benefits of projects in which bio-oil is used in stand alone plants for power generation. The ranges and reference case for bio-oil in stand alone applications show that these projects have a substantially lower financial gap than the current reference case based on wood chips [nl

  9. Spontaneous slip reduction of low-grade isthmic spondylolisthesis following circumferential release via bilateral minimally invasive transforaminal lumbar interbody fusion: technical note and short-term outcome.

    Science.gov (United States)

    Pan, Jie; Li, Lijun; Qian, Lie; Zhou, Wei; Tan, Jun; Zou, Le; Yang, Mingjie

    2011-02-15

    STUDY DESIGN.: Retrospective clinical data analysis. OBJECTIVE.: To investigate and verify our philosophy of spontaneous slip reduction following circumferential release via bilateral minimally invasive transforaminal lumbar interbody fusion (Mini-TLIF) for treatment of low-grade symptomatic isthmic spondylolisthesis. SUMMARY OF BACKGROUND DATA.: Symptomatic isthmic spondylolisthesis usually requires surgical intervention, and the most currently controversial focus is on method and degree of reduction; and Mini-TLIF is an attractive surgical procedure for isthmic spondylolisthesis. METHODS.: Between February 2004 and June 2008, 21 patients with low-grade isthmic spondylolisthesis underwent Mini-TLIF in our institute. Total resection of the scar around the pars interarticularis liberated the nerve roots, achieving posterior release as well. The disc was thoroughly resected, and the disc space was gradually distracted and thoroughly released with sequential disc shavers until rupture of anulus conjunct with anterior longitudinal ligament, accomplishing anterior release, so as to insert Cages. Because of circumferential release, the slipped vertebrae would tend to obtain spontaneous reduction, and with pedicle screw fixation, additional reduction would be achieved without any application of posterior translation force. Radiographs, Visual Analogue Scale, and Oswestry Disability Index were documented. All the cases were followed up for 10 to 26 months. RESULTS.: Slip percentage was reduced from 24.2% ± 6.9% to 10.5% ± 4.0%, and foraminal area percentage increased from 89.1% ± 3.0% to 93.6% ± 2.1%. Visual Analogue Scale and Oswestry Disability Index decreased from 7.8 ± 1.5 to 2.1 ± 1.1 and from 53.3 ± 16.2 to 17.0 ± 7.8, respectively. No neurologic complications were encountered. There were no signs of instrumentation failure. The fusion rate approached 100%. CONCLUSION.: Slip reduction is based on circumferential release. The procedure can be well performed

  10. Charactrization of a Li-ion battery based stand-alone a-Si photovoltaic system

    International Nuclear Information System (INIS)

    Hamid Vishkasougheh, Mehdi; Tunaboylu, Bahadir

    2014-01-01

    Highlights: • An Li-ion battery based stand-alone a-Si PV was designed. The system composed of three a-Si panels with an efficiency of 7% and 40 cells of LFP batteries. • Effects of solar radiation and environmental temperature for three cities, Istanbul, Ankara, and Adana, have been investigated on a-Si panels. • Using transition formulas BSPV outputs are predictable for any location out of standard test condition. - Abstract: The number of photovoltaic (PV) system installations is increasing rapidly. As more people learn about this versatile and often cost-effective power option, this trend will accelerate. This document presents a recommended design for a battery based stand-alone photovoltaic system (BSPV). BSPV system has the ability to be applied in different areas, including warning signals, lighting, refrigeration, communication, residential water pumping, remote sensing, and cathodic protection. The presented calculation method gives a proper idea for a system sizing technique. Based on application load, different scenarios are possible for designing a BSPV system. In this study, a battery based stand-alone system was designed. The electricity generation part is three a-Si panels, which are connected in parallel, and for the storage part LFP (lithium iron phosphate) battery was used. The high power LFP battery packs are 40 cells each 8S5P (configured 8 series 5 parallel). Each individual pack weighs 0.5 kg and is 25.6 V. In order to evaluate the efficiency of a-Si panels with respect to the temperature and the solar irradiation, cities of Istanbul, Ankara and Adana in Turkey were selected. Temperature and solar irradiation were gathered from reliable sources and by using translation equations, current and voltage output of panels were calculated. As a result of these calculations, current and energy outputs were computed by considering an average efficient solar irradiation time value per day in Turkey. The calculated power values were inserted to a

  11. Charactrization of a Li-ion battery based stand-alone a-Si photovoltaic system

    Energy Technology Data Exchange (ETDEWEB)

    Hamid Vishkasougheh, Mehdi, E-mail: mehdi.hamid2@gmail.com [Istanbul Sehir University, Kubakisi Caddesi, No: 27, Altunizade, Uskudar, Istanbul 34662 (Turkey); Tunaboylu, Bahadir [Istanbul Sehir University, Kubakisi Caddesi, No: 27, Altunizade, Uskudar, Istanbul 34662 (Turkey); Marmara Research Center, Materials Institute, PO Box 21, Gebze, Kocaeli 41470 (Turkey)

    2014-11-01

    Highlights: • An Li-ion battery based stand-alone a-Si PV was designed. The system composed of three a-Si panels with an efficiency of 7% and 40 cells of LFP batteries. • Effects of solar radiation and environmental temperature for three cities, Istanbul, Ankara, and Adana, have been investigated on a-Si panels. • Using transition formulas BSPV outputs are predictable for any location out of standard test condition. - Abstract: The number of photovoltaic (PV) system installations is increasing rapidly. As more people learn about this versatile and often cost-effective power option, this trend will accelerate. This document presents a recommended design for a battery based stand-alone photovoltaic system (BSPV). BSPV system has the ability to be applied in different areas, including warning signals, lighting, refrigeration, communication, residential water pumping, remote sensing, and cathodic protection. The presented calculation method gives a proper idea for a system sizing technique. Based on application load, different scenarios are possible for designing a BSPV system. In this study, a battery based stand-alone system was designed. The electricity generation part is three a-Si panels, which are connected in parallel, and for the storage part LFP (lithium iron phosphate) battery was used. The high power LFP battery packs are 40 cells each 8S5P (configured 8 series 5 parallel). Each individual pack weighs 0.5 kg and is 25.6 V. In order to evaluate the efficiency of a-Si panels with respect to the temperature and the solar irradiation, cities of Istanbul, Ankara and Adana in Turkey were selected. Temperature and solar irradiation were gathered from reliable sources and by using translation equations, current and voltage output of panels were calculated. As a result of these calculations, current and energy outputs were computed by considering an average efficient solar irradiation time value per day in Turkey. The calculated power values were inserted to a

  12. Posterior lumbar interbody fusion using non resorbable poly-ether-ether-ketone versus resorbable poly-L-lactide-co-D,L-lactide fusion devices. Clinical outcome at a minimum of 2-year follow-up.

    Science.gov (United States)

    Jiya, Timothy U; Smit, T; van Royen, B J; Mullender, M

    2011-04-01

    Previous papers on resorbable poly-L-lactide-co-D,L-lactide (PLDLLA) cages in spinal fusion have failed to report adequately on patient-centred clinical outcome measures. Also comparison of PLDLLA cage with a traditionally applicable counterpart has not been previously reported. This is the first randomized prospective study that assesses clinical outcome of PLDLLA cage compared with a poly-ether-ether-ketone (PEEK) implant. Twenty-six patients were randomly assigned to undergo instrumented posterior lumbar interbody fusion (PLIF) whereby either a PEEK cage or a PLDLLA cage was implanted. Clinical outcome based on visual analogue scale scores for leg pain and back pain, as well as Oswestry Disability Index (ODI) and SF-36 questionnaires were documented and analysed. When compared with preoperative values, all clinical parameters have significantly improved in the PEEK group at 2 years after surgery with the exception of SF-36 general health, SF-36 mental health and SF-36 role emotional scores. No clinical parameter showed significant improvement at 2 years after surgery compared with preoperative values in the PLDLLA patient group. Only six patients (50%) in the PLDLLA group showed improvement in the VAS scores for leg and back pain as well as the ODI, as opposed to 10 patients (71%) in the PEEK group. One-third of the patients in the PLDLLA group actually reported worsening of their pain scores and ODI. Three cases of mild to moderate osteolysis were seen in the PLDLLA group. Following up on our preliminary report, these 2-year results confirm the superiority of the PEEK implant to the resorbable PLDLLA implant in aiding spinal fusion and alleviating symptoms following PLIF in patients with degenerative spondylolisthesis associated with either canal stenosis or foramen stenosis or both and emanating from a single lumbar segment.

  13. Loss-of-load probabilities for stand-alone photovoltaic systems

    International Nuclear Information System (INIS)

    Klein, S.A.; Beckman, W.A.

    1989-01-01

    A general method is presented for estimating the loss-of-load probability of stand-alone photovoltaic systems. The method was developed by correlating simulation results. The simulations were driven with synthetic radiation sequences having the same statistical significance as available historical data. The methods assumes a constant nighttime load and accounts for the distribution and persistence in daily solar radiation data. It is shown that the 10 year average performance of systems having loss-of-load probabilities less than about 0.01 can vary greatly from one ten year period to the next and thereby cannot be considered realistic performance estimates of a system during its lifetime. (author). 26 refs, 15 figs, 4 tabs

  14. Stand-alone version of the 11kW Gaia wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Bindner, H.; Rosas, P.A.C.; Teodorescu, R.; Blaabjerg, F.

    2004-09-15

    This report describes the development of a stand-alone version of the 11kW Gaia wind turbine. Various possible configurations are investigated and a configuration using a back-to-back converter is chosen. A model is developed for controller design of the fast controllers of the unit. Controllers are designed and a prototype is built for testing. The report documents the performance of the prototype through measurements done on the full scale prototype installed in a test facility where it has been tested both as a standalone unit and in parallel with a diesel genset. For system wide power quality assessment and controller design a dynamic performance assessment model has been developed. (au)

  15. Size optimization of stand-alone photovoltaic (PV) room air conditioners

    International Nuclear Information System (INIS)

    Chen, Chien-Wei; Zahedi, A.

    2006-01-01

    Sizing of a stand-alone PV system determines the main cost of the system. PV electricity cost is determined by the amount of solar energy received, hence the actual climate and weather conditions such as solar irradiance and ambient temperature affect the size required and cost of the system. Air conditioning demand also depends on the weather conditions. Therefore, sizing a PV powered air conditioner must consider the characteristics of local climate and temperature. In this paper, sizing procedures and special considerations for air conditioning under Melbourne's climatic conditions is presented. The reliability of various PV-battery size combinations is simulated by MATLAB. As a result, excellent system performance can be predicated.(Author)

  16. An Analysis of Stand-alone GPS Quality and Simulated GNSS Quality for Road Pricing

    DEFF Research Database (Denmark)

    Zabic, Martina; Nielsen, Otto Anker

    2006-01-01

    Use of GPS for road pricing has often been suggested as the way of creating more efficient charging strategies than existing systems based on cordon lines or time use. In Denmark, Copenhagen participated with the AKTA project in the PRoGRESS programme, sponsored by the EU. The major part...... of the AKTA project was to equip 500 cars with GPS receivers. The paper presents the methods and results from a study of GPS quality in relation to road pricing in a dense urban area. The collected data from 500 cars over a two-year period in the Copenhagen region was analyzed in order to determine whether...... the stand alone GPS quality and reliability is adequate for implementation of an operational road pricing system in Copenhagen. The results from the analysis show that the satellite availability in Copenhagen is not sufficient to form the basis for a reliable operational road pricing system. The narrow...

  17. Integrated Three-Port DC-DC Converter for Photovoltaic (PV) Battery Stand-alone Systems

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Andersen, Michael A. E.

    2016-01-01

    of solar energy. Moreover, a novel transformer configuration enables variable turns ratio controlled by the phase between the two current excitations subjected to the primary windings, allowing a wider input/output range. 1 kW experimental prototype has been built to demonstrate a wellmanaged power flow......Several power sources such as PV solar arrays and battery are often used to manage the power flow for a photovoltaic (PV) based stand-alone power system due to the fluctuation nature of solar energy resource, and deliver a continuous power to the users in an appropriate form. Traditionally, three...... different single-input single-output (SISO) dc/dc converters would have been used. To reduce the cost and improve the power density of the system, an integrated three-port isolated dc/dc converter is proposed in this paper. It can realize all functions of the energy delivery due to the fluctuation nature...

  18. Study of Stand-Alone Microgrid under Condition of Faults on Distribution Line

    Science.gov (United States)

    Malla, S. G.; Bhende, C. N.

    2014-10-01

    The behavior of stand-alone microgrid is analyzed under the condition of faults on distribution feeders. During fault since battery is not able to maintain dc-link voltage within limit, the resistive dump load control is presented to do so. An inverter control is proposed to maintain balanced voltages at PCC under the unbalanced load condition and to reduce voltage unbalance factor (VUF) at load points. The proposed inverter control also has facility to protect itself from high fault current. Existing maximum power point tracker (MPPT) algorithm is modified to limit the speed of generator during fault. Extensive simulation results using MATLAB/SIMULINK established that the performance of the controllers is quite satisfactory under different fault conditions as well as unbalanced load conditions.

  19. Solar pv fed stand-alone excitation system of a synchronous machine for reactive power generation

    Science.gov (United States)

    Sudhakar, N.; Jain, Siddhartha; Jyotheeswara Reddy, K.

    2017-11-01

    This paper presents a model of a stand-alone solar energy conversion system based on synchronous machine working as a synchronous condenser in overexcited state. The proposed model consists of a Synchronous Condenser, a DC/DC boost converter whose output is fed to the field of the SC. The boost converter is supplied by the modelled solar panel and a day time variable irradiance is fed to the panel during the simulation time. The model also has one alternate source of rechargeable batteries for the time when irradiance falls below a threshold value. Also the excess power produced when there is ample irradiance is divided in two parts and one is fed to the boost converter while other is utilized to recharge the batteries. A simulation is done in MATLAB-SIMULINK and the obtained results show the utility of such modelling for supplying reactive power is feasible.

  20. Use of small stand-alone Internet nodes as a distributed control system

    Science.gov (United States)

    Goodwin, Robert W.; Kucera, Michael J.; Shea, Michael F.

    1994-12-01

    For several years, the standard model for accelerator control systems has been workstation consoles connected to VME local stations by a Local Area Network with analog and digital data being accessed via a field bus to custom I/O interface electronics. Commercially available hardware has now made it possible to implement a small stand-alone data acquisition station that combines the LAN connection, the computer, and the analog and digital I/O interface on a single board. This eliminates the complexity of a field bus and the associated proprietary I/O hardware. A minimum control system is one data acquisition station and a Macintosh or workstation console, both connected to the network; larger systems have more consoles and nodes. An implementation of this architecture is described along with performance and operational experience.

  1. Stand-Alone Photovoltaic System Operation with Energy Management and Fault Tolerant

    International Nuclear Information System (INIS)

    Jmashidpour, Ehsan; Poure, Philippe; Gholipour, E.; Saadate, Shahrokh

    2017-01-01

    This paper presents a stand-alone photovoltaic (PV) system with a fault tolerant operation capability. An energy management method is provided to keep the balance between produced and consumed energy instantaneously. As the storage element, an Ultra-Capacitor (UC) pack is used for facing high frequency variation of the load/source, and batteries are in charge of slow load /source variations. A Maximum Power Point Tracking (MPPT) algorithm is applied to control the boost converter of the PV source to achieve the maximum power. In order to improve the micro-grid service continuity and reliability, a fast fault diagnosis method based on the converter current shape for PV source is applied. Finally, the validity of the proposed energy management and the fault diagnosis method is confirmed by the simulation and experimental results. (author)

  2. Power quality improvement of a stand-alone power system subjected to various disturbances

    Science.gov (United States)

    Lone, Shameem Ahmad; Mufti, Mairaj Ud-Din

    In wind-diesel stand-alone power systems, the disturbances like random nature of wind power, turbulent wind, sudden changes in load demand and the wind park disconnection effect continuously the system voltage and frequency. The satisfactory operation of such a system is not an easy task and the control design has to take in to account all these subtleties. For maintaining the power quality, generally, a short-term energy storage device is used. In this paper, the performance of a wind-diesel system associated with a superconducting magnetic energy storage (SMES) system is studied. The effect of installing SMES at wind park bus/load bus, on the system performance is investigated. To control the exchange of real and reactive powers between the SMES unit and the wind-diesel system, a control strategy based on fuzzy logic is proposed. The dynamic models of the hybrid power system for most common scenarios are developed and the results presented.

  3. System Simulation by Recursive Feedback: Coupling a Set of Stand-Alone Subsystem Simulations

    Science.gov (United States)

    Nixon, D. D.

    2001-01-01

    Conventional construction of digital dynamic system simulations often involves collecting differential equations that model each subsystem, arran g them to a standard form, and obtaining their numerical gin solution as a single coupled, total-system simultaneous set. Simulation by numerical coupling of independent stand-alone subsimulations is a fundamentally different approach that is attractive because, among other things, the architecture naturally facilitates high fidelity, broad scope, and discipline independence. Recursive feedback is defined and discussed as a candidate approach to multidiscipline dynamic system simulation by numerical coupling of self-contained, single-discipline subsystem simulations. A satellite motion example containing three subsystems (orbit dynamics, attitude dynamics, and aerodynamics) has been defined and constructed using this approach. Conventional solution methods are used in the subsystem simulations. Distributed and centralized implementations of coupling have been considered. Numerical results are evaluated by direct comparison with a standard total-system, simultaneous-solution approach.

  4. Comparison of plate-cage construct and stand-alone anchored spacer in the surgical treatment of three-level cervical spondylotic myelopathy: a preliminary clinical study.

    Science.gov (United States)

    Shi, Sheng; Liu, Zu-De; Li, Xin-Feng; Qian, Lie; Zhong, Gui-Bin; Chen, Fang-Jing

    2015-09-01

    Although stand-alone cages were advocated to be superior to plate-cage construct (PCC) because of comparable clinical outcomes and fewer plate-related complications, cage dislocation and subsidence were frequently mentioned in multilevel fusion. There are some concerns about whether these issues can be effectively prevented in multilevel anterior cervical discectomy and fusion (ACDF) by stand-alone anchored spacer (SAAS). The aim was to compare clinical outcomes, radiologic parameters, and complications of PCC and SAAS in the treatment of three-level cervical spondylotic myelopathy (CSM). This was a retrospective comparative study. A total of 38 consecutive patients with three-level CSM (ACDF with PCC, 20 patients; ACDF with SAAS, 18 patients) were reviewed. Clinical outcomes were assessed using Japanese Orthopaedic Association and Neck Disability Index. The radiologic evaluations included cervical alignment (CA), segmental angle (SA), postoperative curvature loss (PCL), and incidence of subsidence. All the aforementioned parameters were compared before and after surgery between two groups. Besides, the aforementioned results were also compared between the two groups. The complications were also recorded. The mean follow-up period was 30.3 months. No significant differences were observed in clinical outcomes between the two groups (p>.05). Additionally, no significant differences existed in fusion rate between the two groups. There were significant differences in PCL of SA and CA and correction of SA between the two groups (pSAAS group, and the potential of SAAS to reduce the incidence of postoperative dysphagia was not proven. No other complications were observed in this study. In the surgical treatment of three-level CSM, PCC is superior to SAAS in correction and maintenance of SA and avoiding cage subsidence, although the technique of ACDF with SAAS yielded encouraging clinical outcomes and high fusion rate. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Imagery rescripting as a stand-alone treatment for patients with social phobia: a case series.

    Science.gov (United States)

    Frets, Petra G; Kevenaar, Ciska; van der Heiden, Colin

    2014-03-01

    The majority of patients with social phobia reports experiencing negative images, usually linked to memories of earlier aversive social experiences. Several studies have indicated that such negative self-imagery appears to have a causal role in maintaining social phobia, which suggests that interventions aimed at dealing with these images could be beneficial in the treatment of social phobia. One potentially powerful approach is imagery rescripting (IR), a clinical intervention that focuses on changing the meaning and impact of unpleasant memories. In the treatment of social phobia IR was only used as part of a broader cognitive-behavioral treatment package. However, we propose that IR alone might also be an effective treatment for this anxiety disorder. The present study reports an initial evaluation of the application of IR as a stand-alone treatment for six adult outpatients presenting with social phobia. A single case series using an A-B replication across patients design was employed. Following a no-treatment baseline period, IR was delivered weekly and patients were followed up for 3 and 6 months. For all patients, substantial reductions were obtained on all outcome measures at post-treatment, and gains were largely maintained at 6-months follow-up. The generalizability of the effects of IR for social phobia is limited by the small number of patients treated by only one therapist. The results of this preliminary case series suggest that IR as a stand alone treatment is an apparently effective intervention in the treatment of patients with social phobia, and indicate that controlled evaluation of its efficacy might be worthwhile. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Optimal expansion planning of stand-alone systems with stochastic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hoese, Alejandro [Instituto de Energia Electrica (IEE), Universidad Nacional de San Juan, (Argentina)

    1997-12-31

    Stand-alone systems in the range of 1 kW - 10 MW are taking relevance in the new (global) liberal concept of energy market. State and private investors are becoming increasingly attention on the use of renewable for these systems, but it must be shown that these non-conventional solutions are competitive with the established conventional ones. The high investment costs and the technical and economic uncertainties coupled with the use of time-dependent energy sources are the mainly inhibiting factors for the decision agents to choose these systems instead of conventional ones. In the paper a new model for optimal expansion planning of hybrid stand-alone generating systems under consideration of uncertainties is presented. This model is at present in {sup d}evelopment state{sup .} Results already obtained in the first steps of this research are promising and some of them are here presented. [Espanol] Los sistemas autocontenidos en el rango de 1 Kw a 10 MW estan tomando importancia en el nuevo (global) concepto liberal del mercado de la energia. Inversionistas privados y del Estado estan poniendo mayor atencion en el uso de energias renovables para estos sistemas, pero debe mostrarse que estas soluciones no-convencionales son competitivas con las convencionales establecidas. Los altos costos de inversion y las incertidumbres tecnicas y economicas aunadamente con el uso de fuentes de energia dependientes del tiempo son los principales factores inhibidores de los factores de decision para escoger estos sistemas en lugar de los convencionales. En este articulo se presenta un nuevo modelo de planeacion de expansion optima de sistemas hibridos autocontenidos de generacion electrica bajo la consideracion de incertidumbres. Este modelo esta actualmente en {sup e}stado de desarrollo{sup .} Los resultados ya obtenidos en las primeras etapas de esta investigacion son prometedores y se presentan algunos de ellos.

  7. Diagnostic value of the stand-alone synthetic image in digital breast tomosynthesis examinations.

    Science.gov (United States)

    Garayoa, Julia; Chevalier, Margarita; Castillo, Maria; Mahillo-Fernández, Ignacio; Amallal El Ouahabi, Najim; Estrada, Carmen; Tejerina, Alejandro; Benitez, Olivia; Valverde, Julio

    2018-02-01

    To demonstrate the non-inferiority of synthetic image (SI) mammography versus full-field digital mammography (FFDM) in breast tomosynthesis (DBT) examinations. An observational, retrospective, single-centre, multireader blinded study was performed, using 2384 images to directly compare SI and FFDM based on Breast Imaging Reporting and Data System (BIRADS) categorisation and visibility of radiological findings. Readers had no access to digital breast tomosynthesis slices. Multiple reader, multiple case (MRMC) receiver operating characteristic (ROC) methodology was used to compare the diagnostic performance of SI and FFDM images. The kappa statistic was used to estimate the inter-reader and intra-reader reliability. The area under the ROC curves (AUC) reveals the non-inferiority of SI versus FFDM based on BIRADS categorisation [difference between AUC (ΔAUC), -0.014] and lesion visibility (ΔAUC, -0.001) but the differences were not statistically significant (p=0.282 for BIRADS; p=0.961 for lesion visibility). On average, 77.4% of malignant lesions were detected with SI versus 76.5% with FFDM. Sensitivity and specificity of SI are superior to FFDM for malignant lesions scored as BIRADS 5 and breasts categorised as BIRADS 1. SI is not inferior to FFDM when DBT slices are not available during image reading. SI can replace FFDM, reducing the dose by 45%. • Stand-alone SI demonstrated performance not inferior for lesion visibility as compared to FFDM. • Stand-alone SI demonstrated performance not inferior for lesion BIRADS categorisation as compared to FFDM. • Synthetic images provide important dose savings in breast tomosynthesis examinations.

  8. Energy management system for stand-alone diesel-wind-biomass microgrid with energy storage system

    International Nuclear Information System (INIS)

    Wang, Chengshan; Liu, Yixin; Li, Xialin; Guo, Li; Qiao, Lei; Lu, Hai

    2016-01-01

    An energy management system for stand-alone microgrid composed of diesel generators, wind turbine generator, biomass generator and an ESS (energy storage system) is proposed in this paper. Different operation objectives are achieved by a hierarchical control structure with different time scales. Firstly, the optimal schedules of the diesel generators, wind turbine generator, biomass generator and ESS are determined fifteen minutes ahead according to the super short-term forecast of load and wind speed in the optimal scheduling layer. Comprehensive analysis which takes the uncertainty of load and wind speed into account is conducted in this layer to minimize the operation cost of the system and ensure a desirable range of the state of charge of the ESS. Secondly, the operation points of each unit are regulated dynamically to guarantee real-time power balance and safety range of diesel generation in the real-time control layer, based on which the response capability when suffering significant forecast deviation and other emergency issues, e.g. sudden load-up can be improved. Finally, the effectiveness of the proposed energy management strategy is verified on an RT-Lab based real-time simulation platform, and the economic performances with different types of ESS are analyzed as well. - Highlights: • A hierarchical control strategy is proposed for a stand-alone microgrid. • The uncertainties of load and wind speed have been considered. • Better economic performance and high reliability of the system can be achieved. • The influences of different energy storage systems have been analyzed.

  9. A Meta-Analytic Review of Stand-Alone Interventions to Improve Body Image.

    Directory of Open Access Journals (Sweden)

    Jessica M Alleva

    Full Text Available Numerous stand-alone interventions to improve body image have been developed. The present review used meta-analysis to estimate the effectiveness of such interventions, and to identify the specific change techniques that lead to improvement in body image.The inclusion criteria were that (a the intervention was stand-alone (i.e., solely focused on improving body image, (b a control group was used, (c participants were randomly assigned to conditions, and (d at least one pretest and one posttest measure of body image was taken. Effect sizes were meta-analysed and moderator analyses were conducted. A taxonomy of 48 change techniques used in interventions targeted at body image was developed; all interventions were coded using this taxonomy.The literature search identified 62 tests of interventions (N = 3,846. Interventions produced a small-to-medium improvement in body image (d+ = 0.38, a small-to-medium reduction in beauty ideal internalisation (d+ = -0.37, and a large reduction in social comparison tendencies (d+ = -0.72. However, the effect size for body image was inflated by bias both within and across studies, and was reliable but of small magnitude once corrections for bias were applied. Effect sizes for the other outcomes were no longer reliable once corrections for bias were applied. Several features of the sample, intervention, and methodology moderated intervention effects. Twelve change techniques were associated with improvements in body image, and three techniques were contra-indicated.The findings show that interventions engender only small improvements in body image, and underline the need for large-scale, high-quality trials in this area. The review identifies effective techniques that could be deployed in future interventions.

  10. Optimal expansion planning of stand-alone systems with stochastic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hoese, Alejandro [Instituto de Energia Electrica (IEE), Universidad Nacional de San Juan, (Argentina)

    1998-12-31

    Stand-alone systems in the range of 1 kW - 10 MW are taking relevance in the new (global) liberal concept of energy market. State and private investors are becoming increasingly attention on the use of renewable for these systems, but it must be shown that these non-conventional solutions are competitive with the established conventional ones. The high investment costs and the technical and economic uncertainties coupled with the use of time-dependent energy sources are the mainly inhibiting factors for the decision agents to choose these systems instead of conventional ones. In the paper a new model for optimal expansion planning of hybrid stand-alone generating systems under consideration of uncertainties is presented. This model is at present in {sup d}evelopment state{sup .} Results already obtained in the first steps of this research are promising and some of them are here presented. [Espanol] Los sistemas autocontenidos en el rango de 1 Kw a 10 MW estan tomando importancia en el nuevo (global) concepto liberal del mercado de la energia. Inversionistas privados y del Estado estan poniendo mayor atencion en el uso de energias renovables para estos sistemas, pero debe mostrarse que estas soluciones no-convencionales son competitivas con las convencionales establecidas. Los altos costos de inversion y las incertidumbres tecnicas y economicas aunadamente con el uso de fuentes de energia dependientes del tiempo son los principales factores inhibidores de los factores de decision para escoger estos sistemas en lugar de los convencionales. En este articulo se presenta un nuevo modelo de planeacion de expansion optima de sistemas hibridos autocontenidos de generacion electrica bajo la consideracion de incertidumbres. Este modelo esta actualmente en {sup e}stado de desarrollo{sup .} Los resultados ya obtenidos en las primeras etapas de esta investigacion son prometedores y se presentan algunos de ellos.

  11. Cortical bone trajectory screw fixation versus traditional pedicle screw fixation for 2-level posterior lumbar interbody fusion: comparison of surgical outcomes for 2-level degenerative lumbar spondylolisthesis.

    Science.gov (United States)

    Sakaura, Hironobu; Miwa, Toshitada; Yamashita, Tomoya; Kuroda, Yusuke; Ohwada, Tetsuo

    2018-01-01

    OBJECTIVE The cortical bone trajectory (CBT) screw technique is a new nontraditional pedicle screw (PS) insertion method. However, the biomechanical behavior of multilevel CBT screw/rod fixation remains unclear, and surgical outcomes in patients after 2-level posterior lumbar interbody fusion (PLIF) using CBT screw fixation have not been reported. Thus, the purposes of this study were to examine the clinical and radiological outcomes after 2-level PLIF using CBT screw fixation for 2-level degenerative lumbar spondylolisthesis (DS) and to compare these outcomes with those after 2-level PLIF using traditional PS fixation. METHODS The study included 22 consecutively treated patients who underwent 2-level PLIF with CBT screw fixation for 2-level DS (CBT group, mean follow-up 39 months) and a historical control group of 20 consecutively treated patients who underwent 2-level PLIF using traditional PS fixation for 2-level DS (PS group, mean follow-up 35 months). Clinical symptoms were evaluated using the Japanese Orthopaedic Association (JOA) scoring system. Bony union was assessed by dynamic plain radiographs and CT images. Surgery-related complications, including symptomatic adjacent-segment disease (ASD), were examined. RESULTS The mean operative duration and intraoperative blood loss were 192 minutes and 495 ml in the CBT group and 218 minutes and 612 ml in the PS group, respectively (p 0.05, respectively). The mean JOA score improved significantly from 12.3 points before surgery to 21.1 points (mean recovery rate 54.4%) at the latest follow-up in the CBT group and from 12.8 points before surgery to 20.4 points (mean recovery rate 51.8%) at the latest follow-up in the PS group (p > 0.05). Solid bony union was achieved at 90.9% of segments in the CBT group and 95.0% of segments in the PS group (p > 0.05). Symptomatic ASD developed in 2 patients in the CBT group (9.1%) and 4 patients in the PS group (20.0%, p > 0.05). CONCLUSIONS Two-level PLIF with CBT screw fixation

  12. Cost-effectiveness of minimally invasive versus open transforaminal lumbar interbody fusion for degenerative spondylolisthesis associated low-back and leg pain over two years.

    Science.gov (United States)

    Parker, Scott L; Adogwa, Owoicho; Bydon, Ali; Cheng, Joseph; McGirt, Matthew J

    2012-07-01

    Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for lumbar spondylolisthesis allows for surgical treatment of back and leg pain while theoretically minimizing tissue injury and accelerating overall recovery. Although the authors of previous studies have demonstrated shorter length of hospital stay and reduced blood loss with MIS versus open-TLIF, short- and long-term outcomes have been similar. No studies to date have evaluated the comprehensive health care costs associated with TLIF procedures or assessed the cost-utility of MIS- versus open-TLIF. As such, we set out to assess previously unstudied end points of health care cost and cost-utility associated with MIS- versus open-TLIF. Thirty patients undergoing MIS-TLIF (n=15) or open-TLIF (n=15) for grade I degenerative spondylolisthesis associated back and leg pain were prospectively studied. Total back-related medical resource use, missed work, and health-state values (quality-adjusted life years [QALYs], calculated from EQ-5D with U.S. valuation) were assessed after two-year follow-up. Two-year resource use was multiplied by unit costs on the basis of Medicare national allowable payment amounts (direct cost) and work-day losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). Difference in mean total cost per QALY gained for MIS- versus open-TLIF was assessed as incremental cost-effectiveness ratio (ICER: COSTmis-COSTopen/QALYmis-QALYopen). MIS versus open-TLIF cohorts were similar at baseline. By two years postoperatively, patients undergoing MIS- versus open-TLIF reported similar mean QALYs gained (0.50 vs. 0.41, P=0.17). Mean total two-year cost of MIS- and open-TLIF was $35,996 and $44,727, respectively. The $8,731 two-year cost savings of MIS- versus open-TLIF did not reach statistical significance (P=0.18) for this sample size. Although our limited sample size prevented statistical significance, MIS- versus open-TLIF was associated with reduced costs over

  13. TRANSFORAMINAL L U MBAR INTERBODY FUSION IN LOW GRADE COMBINED LYTIC AND DEGENERATIVE SPONDYLOLIDTHESIS : FUNCTIONAL OUTCOME OF 21 CASES

    Directory of Open Access Journals (Sweden)

    Suresh

    2015-10-01

    Full Text Available BACKGROUND: Spondylolisthesis is a heterogenous disorder characterised by subluxation of a vertebral body in sagittal plane occuring frequently at l4 - 5 and l5 - S1commonest being isthmic and degenerative variety. While majority are asymptomatic, a subset do produce pain with neurology. Complete decompression of roots is essential, as is the need for solid stabi lization. Several fusion techniques were reported in literature like PLF, TLIF, PLF, ALIF On theoretical grounds, TLIF has been suggested to be safe and result in an improved outcome compared to other techniques. Data to support this view, are lacking. M ETHODS: A total of 21 patients (age range, 27 - 62 years with adult isthmic and degenerative spondylolisthesis were operated. There were 8 males and 13 females with mean age of 46.8 pre - op and 2 - year follow - up, pain (VAS and functional disability were quan tified by Oswestry Disability Index (ODI.Radiological union assessed with xrays by Brantigen and Steffee criteria. The global outcome was excellent in 90%.and 92% fusion. 2 patients presented motor deficit which did not recover. RESULTS: The follow - up was for 2 years. The mean VAS score for low back pain improved from 7.0 preoperatively to 2.1, as did the mean VAS score for leg pain from 6.7 to 1.4 and the mean ODI from 59.5% to 11.3%. CONCLUSION: TLIF does affect the 2 - year outcome of surgical treatment of spondylolisthesis with decreased back pain and ODI’s, with advantages of minimal thecal retraction, restored segmental lordosis and preserved posterior tension band.

  14. Key factors for the implementation of successful, stand-alone village electrification schemes in Peru

    Science.gov (United States)

    Sanchez-Campos, Teodoro

    The hypothesis of this work is that there are social, financial, technical, managerial institutional and political key factors that may either support or prevent the success of small stand alone energy systems in rural areas. This research work aims at contributing to the identification of such factors and study their relevance to the performance and sustainability of stand alone energy systems in rural areas; to meet its purpose, a wide range of literature was reviewed including rural electrification programmes and projects, research and development projects on access to electricity in rural areas, impact studies and others, and a field research survey was done the Andes and Upper Jungle regions in Peru. Nineteen possible critical factors were identified, thirteen with relevance at the local context (the community or village), and six with relevance at the national (or wider) context. From literature review it was found that the possible local critical factors were relevant only to four categories of factors instead of the six considered initially (i.e. social, financial, technological and managerial): the other two categories, political and institutional were found to be more relevant to the national context, therefore those were included in the group of possible critical factors of wider context. A series of questionnaires were designed to collect field data information, which was later used to analyse and establish the relation of each identified factor with the success of the systems studied. The survey research was implemented in 14 villages, 7 with small diesel sets and 7 with small hydropower schemes, all spread in the Andes and Upper Jungle of Peru, which were carefully selected to be representative of regions with isolated stand alone systems and with different socioeconomic background. Out of the 13 possible critical factors of local context, it was found that only 3 are really critical, the others are important but not critical; one of them (technical

  15. Multi-objective analytical model for optimal sizing of stand-alone photovoltaic water pumping systems

    International Nuclear Information System (INIS)

    Olcan, Ceyda

    2015-01-01

    Highlights: • An analytical optimal sizing model is proposed for PV water pumping systems. • The objectives are chosen as deficiency of power supply and life-cycle costs. • The crop water requirements are estimated for a citrus tree yard in Antalya. • The optimal tilt angles are calculated for fixed, seasonal and monthly changes. • The sizing results showed the validity of the proposed analytical model. - Abstract: Stand-alone photovoltaic (PV) water pumping systems effectively use solar energy for irrigation purposes in remote areas. However the random variability and unpredictability of solar energy makes difficult the penetration of PV implementations and complicate the system design. An optimal sizing of these systems proves to be essential. This paper recommends a techno-economic optimization model to determine optimally the capacity of the components of PV water pumping system using a water storage tank. The proposed model is developed regarding the reliability and cost indicators, which are the deficiency of power supply probability and life-cycle costs, respectively. The novelty is that the proposed optimization model is analytically defined for two-objectives and it is able to find a compromise solution. The sizing of a stand-alone PV water pumping system comprises a detailed analysis of crop water requirements and optimal tilt angles. Besides the necessity of long solar radiation and temperature time series, the accurate forecasts of water supply needs have to be determined. The calculation of the optimal tilt angle for yearly, seasonally and monthly frequencies results in higher system efficiency. It is, therefore, suggested to change regularly the tilt angle in order to maximize solar energy output. The proposed optimal sizing model incorporates all these improvements and can accomplish a comprehensive optimization of PV water pumping systems. A case study is conducted considering the irrigation of citrus trees yard located in Antalya, Turkey

  16. Five-year durability of stand-alone interspinous process decompression for lumbar spinal stenosis

    Directory of Open Access Journals (Sweden)

    Nunley PD

    2017-09-01

    Full Text Available Pierce D Nunley,1 Vikas V Patel,2 Douglas G Orndorff,3 William F Lavelle,4 Jon E Block,5 Fred H Geisler6 1Spine Institute of Louisiana, Shreveport, LA, 2The Spine Center, University of Colorado Hospital, Denver, CO, 3Spine Colorado, Mercy Regional Hospital, Durango, CO, 4Upstate Bone and Joint Center, East Syracuse, NY, 5Independent Consultant, San Francisco, CA, 6Independent Consultant, Chicago, IL, USA Background: Lumbar spinal stenosis is the most common indication for spine surgery in older adults. Interspinous process decompression (IPD using a stand-alone spacer that functions as an extension blocker offers a minimally invasive treatment option for intermittent neurogenic claudication associated with spinal stenosis.Methods: This study evaluated the 5-year clinical outcomes for IPD (Superion® from a randomized controlled US Food and Drug Administration (FDA noninferiority trial. Outcomes included Zurich Claudication Questionnaire (ZCQ symptom severity (ss, physical function (pf, and patient satisfaction (ps subdomains, leg and back pain visual analog scale (VAS, and Oswestry Disability Index (ODI.Results: At 5 years, 84% of patients (74 of 88 demonstrated clinical success on at least two of three ZCQ domains. Individual ZCQ domain success rates were 75% (66 of 88, 81% (71 of 88, and 90% (79 of 88 for ZCQss, ZCQpf, and ZCQps, respectively. Leg and back pain success rates were 80% (68 of 85 and 65% (55 of 85, respectively, and the success rate for ODI was 65% (57 of 88. Percentage improvements over baseline were 42%, 39%, 75%, 66%, and 58% for ZCQss, ZCQpf, leg and back pain VAS, and ODI, respectively (all P<0.001. Within-group effect sizes were classified as very large for four of five clinical outcomes (ie, >1.0; all P<0.0001. Seventy-five percent of IPD patients were free from reoperation, revision, or supplemental fixation at their index level at 5 years.Conclusion: After 5 years of follow-up, IPD with a stand-alone spacer provides

  17. Efficiency of hydrogen gas production in a stand-alone solar hydrogen system

    International Nuclear Information System (INIS)

    Singh, K.; Tamakloe, R.Y.

    2003-01-01

    Many photovoltaic systems operate in a decentralised electricity producing system, or stand-alone mode and the total energy demand is met by the output of the photovoltaic array. The output of the photovoltaic system fluctuates and is unpredictable for many applications making some forms of energy storage system necessary. The role of storage medium is to store the excess energy produced by the photovoltaic arry, to absorb momentary power peaks and to supply energy during sunless periods. One of the storage modes is the use of electrochemical techniques, with batteries and water electrolysis as the most important examples. The present study includes three main parts: the first one is the hydrogen production form the electrolysis of water depending on the DC output current of the photovoltaic (PV) energy source and the charging of the battery. The second part presents the influence of various parameters on the efficiency of hydrogen gas production. The final part includes simulation studies with focus on solar hydrogen efficiency under the influence of various physical and chemical parameters. For a 50W panel-battery-electrolyser system, the dependence of volume of hydrogen gas on voltage, current and power yielded a maximum efficiency of 13.6% (author)

  18. Control of a Stand-Alone Variable Speed Wind Energy Supply System †

    Directory of Open Access Journals (Sweden)

    Mohamed M. Hamada

    2013-04-01

    Full Text Available This paper presents a simple control strategy for the operation of a variable speed stand-alone wind turbine with a permanent magnet synchronous generator (PMSG. The PMSG is connected to a three phase resistive load through a switch mode rectifier and a voltage source inverter. Control of the generator side converter is used to achieve maximum power extraction from the available wind power. Control of the DC-DC bidirectional buck-boost converter, which is connected between batteries bank and DC-link voltage, is used to maintain the DC-link voltage at a constant value. It is also used to make the batteries bank stores the surplus of wind energy and supplies this energy to the load during a wind power shortage. The load side voltage source inverter uses a relatively complex vector control scheme to control the output load voltage in terms of amplitude and frequency. The control strategy works under wind speed variation as well as with variable load. Extensive simulation results have been performed using MATLAB/SIMULINK.

  19. Optimal sizing method for constituent elements of stand-alone photovoltaic power systems

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Hirotada; Oi, Yoichi [Hokuriku Electric Power Co., Inc. Toyama (Japan)

    1988-12-25

    The purpose of the report was to calculate the optimal volume of constituent elements of stand-alone photovoltaic power systems, based on the distribution of global radiation on an inclined surface (herein-after called flux of solar radiation), which had been previously measured, and the size of load to be supplied. The least power generation cost was calculated, supposing that setting load was 176kWh/month and the loss of load probability (LOLP) was 1%, by using actual amount of solar radiation in May 1985. The cost was divided into two components: one was proportionate to the size of solar cell, and the other was in proportion to the battery volume. And then, the cost of twenty-year operation(TLC) was calculated. The size of array and the battery volume, which minimize the cost, can be determined when TLC is differentiate. Since auxiliary power source is not attached to this system, it is necessary to restrict the load in order to meet the electric power shortage. In case of the cost at construction in 1984, a standard model indicating the least power generation cost is a photovoltaic system with the array size of A=49.0m{sup 2} and the battery volume of Q=568(Ah). 4 refs., 9 figs., 10 tabs.

  20. Battery Storage Technologies for Electrical Applications: Impact in Stand-Alone Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Daniel Akinyele

    2017-11-01

    Full Text Available Batteries are promising storage technologies for stationary applications because of their maturity, and the ease with which they are designed and installed compared to other technologies. However, they pose threats to the environment and human health. Several studies have discussed the various battery technologies and applications, but evaluating the environmental impact of batteries in electrical systems remains a gap that requires concerted research efforts. This study first presents an overview of batteries and compares their technical properties such as the cycle life, power and energy densities, efficiencies and the costs. It proposes an optimal battery technology sizing and selection strategy, and then assesses the environmental impact of batteries in a typical renewable energy application by using a stand-alone photovoltaic (PV system as a case study. The greenhouse gas (GHG impact of the batteries is evaluated based on the life cycle emission rate parameter. Results reveal that the battery has a significant impact in the energy system, with a GHG impact of about 36–68% in a 1.5 kW PV system for different locations. The paper discusses new batteries, strategies to minimize battery impact and provides insights into the selection of batteries with improved cycling capacity, higher lifespan and lower cost that can achieve lower environmental impacts for future applications.

  1. Performance and Simulation of a Stand-alone Parabolic Trough Solar Thermal Power Plant

    Science.gov (United States)

    Mohammad, S. T.; Al-Kayiem, H. H.; Assadi, M. K.; Gilani, S. I. U. H.; Khlief, A. K.

    2018-05-01

    In this paper, a Simulink® Thermolib Model has been established for simulation performance evaluation of Stand-alone Parabolic Trough Solar Thermal Power Plant in Universiti Teknologi PETRONAS, Malaysia. This paper proposes a design of 1.2 kW parabolic trough power plant. The model is capable to predict temperatures at any system outlet in the plant, as well as the power output produced. The conditions that are taken into account as input to the model are: local solar radiation and ambient temperatures, which have been measured during the year. Other parameters that have been input to the model are the collector’s sizes, location in terms of latitude and altitude. Lastly, the results are presented in graphical manner to describe the analysed variations of various outputs of the solar fields obtained, and help to predict the performance of the plant. The developed model allows an initial evaluation of the viability and technical feasibility of any similar solar thermal power plant.

  2. Comparative analysis of distributed MPPT controllers for partially shaded stand alone photovoltaic systems

    International Nuclear Information System (INIS)

    Muthuramalingam, M.; Manoharan, P.S.

    2014-01-01

    Highlights: • Analyzes the performance of ANN and ANFIS MPPT algorithms by stand alone PV system. • ISSBC with ANFIS can provide the overall efficiency higher than ANN. • CHBMLI integrate with SHE ANN modulation technique improve output voltage quality. • Simulation and hardware results show the ANFIS algorithm efficient than ANN algorithm. - Abstract: This paper presents a unique combination of an interleaved soft switched boost converter (ISSBC) run by a set of two photovoltaic panel (PV) with a distributed MPPT, suitable to guarantee MPPT even under partial shadowed conditions, managed by an adaptive neuro fuzzy inference system trained by the training data derived from a particle swarm optimization (PSO–ANFIS) unit. The ISSBC is followed by a, single phase cascaded H bridge five-level inverter (CHI) driven by the individual DC outputs of the ISSBC, with selective harmonic elimination scheme to eliminate typically the seventh order harmonics. A comparison of different intelligent distributed maximum power point tracking (MPPT) algorithms for photovoltaic (PV) system under partial shadow conditions is carried out. The use of the ISSBC guarantees mitigation of ripple and it is meant to handle higher currents with minimal switching losses. Simulation was carried out in the Matlab Simulink environment and an experimental verification with a scaled down model validated the proposed scheme. It has been thus established, by both simulation and experimental verification, that the PSO–ANFIS model of distributed MPPT scheme of control outperforms other schemes of control for MPPT

  3. Can aqueous hydrogen peroxide be used as a stand-alone energy source?

    International Nuclear Information System (INIS)

    Disselkamp, Robert S.

    2010-01-01

    A novel electrochemical scheme to convert a stand-alone supply of aqueous hydrogen peroxide into a fuel cell-ready stream of hydrogen gas plus aqueous hydrogen peroxide is described. The electrochemical cell, consisting of a solid base and solid acid electrocatalyst, together with a proton exchange membrane, comprise the system that converts aqueous hydrogen peroxide into separate gas streams of oxygen and hydrogen. Aqueous hydrogen peroxide is contained in the anode compartment only and exists in the region where oxygen gas is formed, whereas the cathode compartment is where hydrogen gas is generated and therefore exists in a reduced state. A near zero theoretical over-potential can be achieved by the choice of basicity and acidity of the electrode materials. The primary cost of the electrochemical cell is electrode construction and the aqueous hydrogen peroxide energy storage compound. Additional research effort is required to experimentally validate the concept and explore the full economic impact should initial studies, based on the design presented here, prove promising. (author)

  4. An intelligent stand-alone ultrasonic device for monitoring local structural damage: implementation and preliminary experiments

    International Nuclear Information System (INIS)

    Pertsch, Alexander; Kim, Jin-Yeon; Wang, Yang; Jacobs, Laurence J

    2011-01-01

    Continuous structural health monitoring has the potential to significantly improve the safety management of aged, in-service civil structures. In particular, monitoring of local damage growth at hot-spot areas can help to prevent disastrous structural failures. Although ultrasonic nondestructive evaluation (NDE) has proved to be effective in monitoring local damage growth, conventional equipment and devices are usually bulky and only suitable for scheduled human inspections. The objective of this research is to harness the latest developments in embedded hardware and wireless communication for developing a stand-alone, compact ultrasonic device. The device is directed at the continuous structural health monitoring of civil structures. Relying on battery power, the device possesses the functionalities of high-speed actuation, sensing, signal processing, and wireless communication. Integrated with contact ultrasonic transducers, the device can generate 1 MHz Rayleigh surface waves in a steel specimen and measure response waves. An envelope detection algorithm based on the Hilbert transform is presented for efficiently determining the peak values of the response signals, from which small surface cracks are successfully identified

  5. Approaches for developing a sizing method for stand-alone PV systems with variable demand

    Energy Technology Data Exchange (ETDEWEB)

    Posadillo, R. [Grupo de Investigacion en Energias y Recursos Renovables, Dpto. de Fisica Aplicada, E.P.S., Universidad de Cordoba, Avda. Menendez Pidal s/n, 14004 Cordoba (Spain); Lopez Luque, R. [Grupo de Investigacion de Fisica para las Energias y Recursos Renovables, Dpto. de Fisica Aplicada. Edificio C2 Campus de Rabanales, 14071 Cordoba (Spain)

    2008-05-15

    Accurate sizing is one of the most important aspects to take into consideration when designing a stand-alone photovoltaic system (SAPV). Various methods, which differ in terms of their simplicity or reliability, have been developed for this purpose. Analytical methods, which seek functional relationships between variables of interest to the sizing problem, are one of these approaches. A series of rational considerations are presented in this paper with the aim of shedding light upon the basic principles and results of various sizing methods proposed by different authors. These considerations set the basis for a new analytical method that has been designed for systems with variable monthly energy demands. Following previous approaches, the method proposed is based on the concept of loss of load probability (LLP) - a parameter that is used to characterize system design. The method includes information on the standard deviation of loss of load probability ({sigma}{sub LLP}) and on two new parameters: annual number of system failures (f) and standard deviation of annual number of failures ({sigma}{sub f}). The method proves useful for sizing a PV system in a reliable manner and serves to explain the discrepancies found in the research on systems with LLP<10{sup -2}. We demonstrate that reliability depends not only on the sizing variables and on the distribution function of solar radiation, but on the minimum value as well, which in a given location and with a monthly average clearness index, achieves total solar radiation on the receiver surface. (author)

  6. Stand-alone excitation synchronous wind power generators with power flow management strategy

    Directory of Open Access Journals (Sweden)

    Tzuen-Lih Chern

    2014-09-01

    Full Text Available This study presents a stand-alone excitation synchronous wind power generator (SESWPG with power flow management strategy (PFMS. The rotor speed of the excitation synchronous generator tracks the utility grid frequency by using servo motor tracking technologies. The automatic voltage regulator governs the exciting current of generator to achieve the control goals of stable voltage. When wind power is less than the needs of the consumptive loading, the proposed PFMS increases motor torque to provide a positive power output for the loads, while keeping the generator speed constant. Conversely, during the periods of wind power greater than output loads, the redundant power of generator production is charged to the battery pack and the motor speed remains constant with very low power consumption. The advantage of the proposed SESWPG is that the generator can directly output stable alternating current (AC electricity without using additional DC–AC converters. The operation principles with software simulation for the system are described in detail. Experimental results of a laboratory prototype are shown to verify the feasibility of the system.

  7. Analysis and control of induction generator supplying stand-alone AC loads employing a Matrix Converter

    Directory of Open Access Journals (Sweden)

    Sumedha Mahajan

    2017-04-01

    Full Text Available This paper proposes a Capacitor Excited Induction Generator (CEIG-Matrix Converter (MC system for feeding stand-alone AC loads. The variable output voltage magnitude and frequency from CEIG is converted into a constant voltage magnitude and frequency at the load terminals by controlling MC using Space Vector Modulation (SVM technique. This single-stage MC is turned up as a good alternative for the proposed system against commonly used AC/DC/AC two stage power converters. The configuration and implementation of the closed-loop control scheme employing dSPACE 1103 real time controller have been fully described in the paper. The proposed closed-loop controller regulates the AC load voltage irrespective of changes in the prime mover speed and load. A method for predetermining the steady-state performance of the proposed system has been developed and described with relevant analytical expressions. The effectiveness of the proposed system is exemplified through simulation results for various operating conditions. The proposed control technique is further validated using an experimental setup developed in the laboratory.

  8. Design of a reliable and low-cost stand-alone micro hydropower station

    Energy Technology Data Exchange (ETDEWEB)

    Kusakana, K.; Munda, J.L. [Tshwane Univ. of Technology, Pretoria (South Africa)

    2008-07-01

    A stand-alone micro-hydropower station was presented. The plant was comprised of a squirrel cage induction machine coupled to a Kaplan water turbine. Power converters were used to control the variable frequency and voltage outputs of the generator caused by variations in water flow. The hydropower plant was installed a farm in the Kwazulu-Natal region of South Africa, and was designed to provide electricity in relation to the low power demand of users in the region as well as according to the site's hydrology and topology. Load forecasts for the 8 houses using the system were conducted. A generator with a higher output than the average power needed to feed the load was selected in order to ensure load supply during peak demand. The system was designed to shore energy generated during off-peak periods in batteries. An AC-DC-AC converter was used as an interface between the generator and the load in order to ensure voltage and frequency stabilization. Simulations of plant components were conducted to demonstrate output power supply during water flow variations. Results of the modelling study indicated that power converters are needed to stabilize generator outputs. The hydropower design is a cost-effective means of supplying power to low-income households. 10 refs., 2 tabs., 7 figs.

  9. Simulation of stand alone PV system; Dokuritsugata taiyoko hatsuden system no simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, H; Ogawa, H; Sekii, Y [Chiba Institute of Technology, Chiba (Japan); Tsuda, I; Nozaki, K [Electrotechnical Laboratory, Tsukuba (Japan); Kurokawa, K [Tokyo University of Agriculture and Technology, Tokyo (Japan)

    1996-10-27

    In order to evaluate the simulation results of a photovoltaic power generation system, an operation simulation was carried out using the actual measured data of a stand alone PV system in Miyakojima, Okinawa Prefecture, so as to make a comparison with the actual operation data. The electric power was supplied to 250 houses and primary/junior high schools in the surrounding villages, which had an average demand load of approximately 90kw and the maximum of approximately 200kw. The power was supplied through the PV power generation in the duration of the sunshine, with an excess power charged in storage batteries and then supplied from the batteries at night. The array capacity was made 750kWp, the output current and storage batteries being characteristic type with an actual efficiency curve used for the inverter. The weather data used were the actual inclined insolation quantity and the outside air temperature data for a period of one month of November. The power charged in excess of 100% in the batteries was termed as an overflow power. With the charging condition 30% or less, a diesel generator was run for a rated operation for one hour, the power of which was termed as a backup power. As a result, the simulation was found nearly in agreement with the actual measurements. 5 refs., 7 figs., 2 tabs.

  10. Solar photovoltaic applications seminar: design, installation and operation of small, stand-alone photovoltaic power systems

    Energy Technology Data Exchange (ETDEWEB)

    1980-07-01

    This seminar material was developed primarily to provide solar photovoltaic (PV) applied engineering technology to the Federal community. An introduction to photoconductivity, semiconductors, and solar photovoltaic cells is included along with a demonstration of specific applications and application identification. The seminar details general systems design and incorporates most known information from industry, academia, and Government concerning small solar cell power system design engineering, presented in a practical and applied manner. Solar PV power system applications involve classical direct electrical energy conversion and electric power system analysis and synthesis. Presentations and examples involve a variety of disciplines including structural analysis, electric power and load analysis, reliability, sizing and optimization; and, installation, operation and maintenance. Four specific system designs are demonstrated: water pumping, domestic uses, navigational and aircraft aids, and telecommunications. All of the applications discussed are for small power requirement (under 2 kilowatts), stand-alone systems to be used in remote locations. Also presented are practical lessons gained from currently installed and operating systems, problems at sites and their resolution, a logical progression through each major phase of system acquisition, as well as thorough design reviews for each application.

  11. Use of Super-Capacitor to Enhance Charging Performance of Stand-Alone Solar PV System

    KAUST Repository

    Huang, B. J.

    2011-01-01

    Introduction: The battery charging performance in a stand-alone solar PV system affects the PV system efficiency and the load operating time. The New Energy Center of National Taiwan University has been devoted to the development of a PWM charging technique to continue charging the lead-acid battery after the overcharge point to increase the battery storage capacity by more than 10%. The present study intends to use the super-capacitor to further increase the charge capacity before the overcharge point of the battery. The super-capacitor is connected in parallel to the lead-acid battery. This will reduce the overall charging impedance during the charge and increase the charging current, especially in sunny weather. A system dynamics model of the lead-acid battery and super-capacitor was derived and the control system simulation was carried out to predict the charging performance for various weathers. It shows that the overall battery impedance decreases and charging power increases with increasing solar radiation. An outdoor comparative test for two identical PV systems with and without supercapacitor was carried out. The use of super-capacitor is shown to be able to increase the lead-acid charging capacity by more than 25% at sunny weather and 10% in cloudy weather. © Springer-Verlag Berlin Heidelberg 2011.

  12. On the economics of stand-alone renewable hybrid power plants in remote regions

    International Nuclear Information System (INIS)

    Petrakopoulou, Fontina

    2016-01-01

    Highlights: • Economic evaluation of three renewable hybrid power plants for off-grid operation. • The high electricity cost of remote regions increases the competitiveness of renewable energy. • The proposed plants are economically viable when compared to the existing situation. • The zero direct emissions of the plants constitute an additional advantage of the plants. - Abstract: In recent years ever more examples of regions that have managed to achieve or orientate themselves toward renewable energy sufficiency are emerging. However, actions to create energy autonomy are mainly the result of isolated activities and they are less driven from fully organized movements. In addition, total energy independence without the support of a centralized electrical grid is yet to be achieved. The objectives of this work are to investigate the associated costs of stand-alone renewable hybrid power plants on a Greek island and compare them to the cost of the currently used fossil-fuel-based conventional plant. The plants examined here are designed to fully cover the electricity needs of the island. Islands may face numerous energy problems and rely heavily on foreign and environmentally-harmful fuels. It is shown that the relatively high cost of electricity of such a remote region can increase the competitiveness and promote the wider incorporation of technologies based on renewable energy sources that may, in other cases, seem economically inferior to business-as-usual energy solutions.

  13. MIRNA-DISTILLER: a stand-alone application to compile microRNA data from databases

    Directory of Open Access Journals (Sweden)

    Jessica K. Rieger

    2011-07-01

    Full Text Available MicroRNAs (miRNA are small non-coding RNA molecules of ~22 nucleotides which regulate large numbers of genes by binding to seed sequences at the 3’-UTR of target gene transcripts. The target mRNA is then usually degraded or translation is inhibited, although thus resulting in posttranscriptional down regulation of gene expression at the mRNA and/or protein level. Due to the bioinformatic difficulties in predicting functional miRNA binding sites, several publically available databases have been developed that predict miRNA binding sites based on different algorithms. The parallel use of different databases is currently indispensable, but highly uncomfortable and time consuming, especially when working with numerous genes of interest. We have therefore developed a new stand-alone program, termed MIRNA-DISTILLER, which allows to compile miRNA data for given target genes from public databases. Currently implemented are TargetScan, microCosm, and miRDB, which may be queried independently, pairwise, or together to calculate the respective intersections. Data are stored locally for application of further analysis tools including freely definable biological parameter filters, customized output-lists for both miRNAs and target genes, and various graphical facilities. The software, a data example file and a tutorial are freely available at http://www.ikp-stuttgart.de/content/language1/html/10415.asp

  14. MIRNA-DISTILLER: A Stand-Alone Application to Compile microRNA Data from Databases.

    Science.gov (United States)

    Rieger, Jessica K; Bodan, Denis A; Zanger, Ulrich M

    2011-01-01

    MicroRNAs (miRNA) are small non-coding RNA molecules of ∼22 nucleotides which regulate large numbers of genes by binding to seed sequences at the 3'-untranslated region of target gene transcripts. The target mRNA is then usually degraded or translation is inhibited, although thus resulting in posttranscriptional down regulation of gene expression at the mRNA and/or protein level. Due to the bioinformatic difficulties in predicting functional miRNA binding sites, several publically available databases have been developed that predict miRNA binding sites based on different algorithms. The parallel use of different databases is currently indispensable, but highly uncomfortable and time consuming, especially when working with numerous genes of interest. We have therefore developed a new stand-alone program, termed MIRNA-DISTILLER, which allows to compile miRNA data for given target genes from public databases. Currently implemented are TargetScan, microCosm, and miRDB, which may be queried independently, pairwise, or together to calculate the respective intersections. Data are stored locally for application of further analysis tools including freely definable biological parameter filters, customized output-lists for both miRNAs and target genes, and various graphical facilities. The software, a data example file and a tutorial are freely available at http://www.ikp-stuttgart.de/content/language1/html/10415.asp.

  15. Outcomes of interbody fusion cages used in 1 and 2-levels anterior cervical discectomy and fusion: titanium cages versus polyetheretherketone (PEEK) cages.

    Science.gov (United States)

    Niu, Chi-Chien; Liao, Jen-Chung; Chen, Wen-Jer; Chen, Lih-Huei

    2010-07-01

    A prospective study was performed in case with cervical spondylosis who underwent anterior cervical discectomy and fusion (ACDF) with titanium or polyetheretherketone (PEEK) cages. To find out which fusion cage yielded better clinical and radiographic results. Although use of autogenous iliac-bone grafts in ACDF for cervical disc diseases remain standard surgical procedure, donor site morbidity and graft collapse or breakage are concerns. Cage technology was developed to prevent these complications. However, there is no comparison regarding the efficacy between titanium and PEEK cage. January 2005 to January 2006, 53 patients who had 1 and 2-levels ACDF with titanium or PEEK cages were evaluated. We measured the rate and amount of interspace collapse, segmental sagittal angulations, and the radiographic fusion success rate. Odom criteria were used to assess the clinical results. The fusion rate was higher in the PEEK group (100% vs. 86.5%, P=0.0335). There was no significant difference between both groups in loss of cervical lordosis (3.2 + or - 2.4 vs. 2.8 + or - 3.4, P=0.166). The mean anterior interspace collapse (1.6 + or - 1.0 mm) in the titanium group was significantly higher than the collapse of the PEEK group (0.5 + or - 0.6 mm) (PPEEK group (PPEEK group achieved an 80% rate of successful clinical outcomes, compared with 75% in the titanium group (P=0.6642). The PEEK cage is superior to the titanium cage in maintaining cervical interspace height and radiographic fusion after 1 and 2-levels anterior cervical decompression procedures.

  16. 49 CFR 1109.4 - Mandatory mediation in rate cases to be considered under the stand-alone cost methodology.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Mandatory mediation in rate cases to be considered... § 1109.4 Mandatory mediation in rate cases to be considered under the stand-alone cost methodology. (a) A... methodology must engage in non-binding mediation of its dispute with the railroad upon filing a formal...

  17. An improved synchronous reference frame phase-locked loop for stand-alone variable speed constant frequency power generation systems

    DEFF Research Database (Denmark)

    Liu, Yi; Xu, Wei; Ke, Longzhang

    2017-01-01

    The phase-locked loop (PLL) based on conventional synchronous reference frame, i.e. dqPLL, is usually employed in grid-connected variable speed constant frequency (VSCF) power generation systems (PGSs). However, the voltage amplitude drop of stand-alone PGSs is often greater than that of the grid...

  18. Analyzing grid extension and stand-alone photovoltaic systems for the cost-effective electrification of Kenya

    NARCIS (Netherlands)

    Zeyringer, Marianne; Pachauri, Shonali; Schmid, Erwin; Schmidt, Johannes; Worrell, Ernst|info:eu-repo/dai/nl/106856715; Morawetz, Ulrich B.

    2015-01-01

    The declaration of 2014-2024 as the Decade of Sustainable Energy for All has catalyzed actions towards achieving universal electricity access. The high costs of building electric infrastructure are a major impediment to improved access, making stand-alone photovoltaic (PV) systems an attractive

  19. Stand-Alone Ethics, Social Responsibility, and Sustainability Course Requirements: A Snapshot from Australia and New Zealand

    Science.gov (United States)

    Rundle-Thiele, Sharyn R.; Wymer, Walter

    2010-01-01

    This article analyzes the extent to which Australian and New Zealand marketing educators use dedicated or stand-alone courses to equip students with alternative views of business. A census of marketing programs in degree-granting universities was conducted. Program brochures were obtained via the Internet and were content analyzed. This study…

  20. Stand-Alone Photovoltaic System Assessment in Warmer Urban Areas in Mexico

    Directory of Open Access Journals (Sweden)

    Alberto-Jesus Perea-Moreno

    2018-01-01

    Full Text Available The aim of this study is to examine the possibility of using a stand-alone photovoltaic system (SAPVS for electricity generation in urban areas in Southern Mexico. In Mexico, an urban area is defined as an area where more than 2500 inhabitants live. Due to constant migration from the countryside to the cities, the number of inhabitants of urban localities has been increasing. Global horizontal irradiation (GHI data were recorded every 10 min during 2014–2016 in Coatzacoalcos in the state of Veracruz located on 18°08′09″ N and 94°27′48″ W. In this study, batteries represented 77% of the total cost, 12 PV panels of 310 W could export 5.41 MWh to the grid, and an inverter with an integrated controller and charger was selected, which decreased the initial cost. The city of Coatzacoalcos was chosen because the average annual temperature is 28°, with an average relative humidity of 75% and an average irradiance of 5.3 kWh/m2/day. An emission factor 0.505 tCO2/MWh of greenhouse gases (GHG were obtained, based on the power system, the reduction of net annual GHG would be 11 tCO2 and a financial revenue of 36.951 × 103 $/tCO2 would be obtained. Financial parameters such as a 36.3% Internal Rate Return (IRR and 3.4 years payback show the financial viability of this investment. SAPVSs in urban areas in Mexico could be a benefit as long as housing has a high consumption of electricity.

  1. The Use of Artificial Neural Networks for Forecasting the Electric Demand of Stand-Alone Consumers

    Science.gov (United States)

    Ivanin, O. A.; Direktor, L. B.

    2018-05-01

    The problem of short-term forecasting of electric power demand of stand-alone consumers (small inhabited localities) situated outside centralized power supply areas is considered. The basic approaches to modeling the electric power demand depending on the forecasting time frame and the problems set, as well as the specific features of such modeling, are described. The advantages and disadvantages of the methods used for the short-term forecast of the electric demand are indicated, and difficulties involved in the solution of the problem are outlined. The basic principles of arranging artificial neural networks are set forth; it is also shown that the proposed method is preferable when the input information necessary for prediction is lacking or incomplete. The selection of the parameters that should be included into the list of the input data for modeling the electric power demand of residential areas using artificial neural networks is validated. The structure of a neural network is proposed for solving the problem of modeling the electric power demand of residential areas. The specific features of generation of the training dataset are outlined. The results of test modeling of daily electric demand curves for some settlements of Kamchatka and Yakutia based on known actual electric demand curves are provided. The reliability of the test modeling has been validated. A high value of the deviation of the modeled curve from the reference curve obtained in one of the four reference calculations is explained. The input data and the predicted power demand curves for the rural settlement of Kuokuiskii Nasleg are provided. The power demand curves were modeled for four characteristic days of the year, and they can be used in the future for designing a power supply system for the settlement. To enhance the accuracy of the method, a series of measures based on specific features of a neural network's functioning are proposed.

  2. Stand-Alone Solar Organic Rankine Cycle Water Pumping System and Its Economic Viability in Nepal

    Directory of Open Access Journals (Sweden)

    Suresh Baral

    2015-12-01

    Full Text Available The current study presents the concept of a stand-alone solar organic Rankine cycle (ORC water pumping system for rural Nepalese areas. Experimental results for this technology are presented based on a prototype. The economic viability of the system was assessed based on solar radiation data of different Nepalese geographic locations. The mechanical power produced by the solar ORC is coupled with a water pumping system for various applications, such as drinking and irrigation. The thermal efficiency of the system was found to be 8% with an operating temperature of 120 °C. The hot water produced by the unit has a temperature of 40 °C. Economic assessment was done for 1-kW and 5-kW solar ORC water pumping systems. These systems use different types of solar collectors: a parabolic trough collector (PTC and an evacuated tube collector (ETC. The economic analysis showed that the costs of water are $2.47/m3 (highest and $1.86/m3 (lowest for the 1-kW system and a 150-m pumping head. In addition, the cost of water is reduced when the size of the system is increased and the pumping head is reduced. The minimum volumes of water pumped are 2190 m3 and 11,100 m3 yearly for 1 kW and 5 kW, respectively. The payback period is eight years with a profitability index of 1.6. The system is highly feasible and promising in the context of Nepal.

  3. Optimum capacity determination of stand-alone hybrid generation system considering cost and reliability

    International Nuclear Information System (INIS)

    Chen, Hung-Cheng

    2013-01-01

    Highlights: ► This paper presents a methodology for the installation capacity optimization. ► Hybrid generation system is optimized by application of adaptive genetic algorithm. ► A cost investigation is made under various conditions and component characteristics. ► The optimization scheme is validated to meet the annual power load demand. -- Abstract: The aim of this work is to present an optimization methodology for the installation capacity of a stand-alone hybrid generation system, taking into consideration the cost and reliability. Firstly, on the basis of derived steady state models of a wind generator (WG), a photovoltaic array (PV), a battery and an inverter, the hybrid generation system is modeled for the purpose of capacity optimization. Secondly, the power system is analyzed for determining both the system structure and the operation control strategy. Thirdly, according to hourly weather database of wind speed, temperature and solar irradiation, annual power generation capacity is estimated for the system match design in order that an annual power load demand can be met. The capacity determination of a hybrid generation system becomes complicated as a result of the uncertainty in the renewable energy together with load demand and the nonlinearity of system components. Aimed at the power system reliability and the cost minimization, the capacity of a hybrid generation system is optimized by application of an adaptive genetic algorithm (AGA) to individual power generation units. A total cost investigation is made under various conditions, such as wind generator power curves, battery discharge depth and the loss of load probability (LOLP). At the end of this work, the capacity of a hybrid generation system is optimized at two installation sites, namely the offshore Orchid Island and Wuchi in Taiwan. The optimization scheme is validated to optimize power capacities of a photovoltaic array, a battery and a wind turbine generator with a relative

  4. The eBioKit, a stand-alone educational platform for bioinformatics.

    Science.gov (United States)

    Hernández-de-Diego, Rafael; de Villiers, Etienne P; Klingström, Tomas; Gourlé, Hadrien; Conesa, Ana; Bongcam-Rudloff, Erik

    2017-09-01

    Bioinformatics skills have become essential for many research areas; however, the availability of qualified researchers is usually lower than the demand and training to increase the number of able bioinformaticians is an important task for the bioinformatics community. When conducting training or hands-on tutorials, the lack of control over the analysis tools and repositories often results in undesirable situations during training, as unavailable online tools or version conflicts may delay, complicate, or even prevent the successful completion of a training event. The eBioKit is a stand-alone educational platform that hosts numerous tools and databases for bioinformatics research and allows training to take place in a controlled environment. A key advantage of the eBioKit over other existing teaching solutions is that all the required software and databases are locally installed on the system, significantly reducing the dependence on the internet. Furthermore, the architecture of the eBioKit has demonstrated itself to be an excellent balance between portability and performance, not only making the eBioKit an exceptional educational tool but also providing small research groups with a platform to incorporate bioinformatics analysis in their research. As a result, the eBioKit has formed an integral part of training and research performed by a wide variety of universities and organizations such as the Pan African Bioinformatics Network (H3ABioNet) as part of the initiative Human Heredity and Health in Africa (H3Africa), the Southern Africa Network for Biosciences (SAnBio) initiative, the Biosciences eastern and central Africa (BecA) hub, and the International Glossina Genome Initiative.

  5. "Candidatus Fokinia solitaria", a Novel "Stand-Alone" Symbiotic Lineage of Midichloriaceae (Rickettsiales.

    Directory of Open Access Journals (Sweden)

    Franziska Szokoli

    Full Text Available Recently, the family Midichloriaceae has been described within the bacterial order Rickettsiales. It includes a variety of bacterial endosymbionts detected in different metazoan host species belonging to Placozoa, Cnidaria, Arthropoda and Vertebrata. Representatives of Midichloriaceae are also considered possible etiological agents of certain animal diseases. Midichloriaceae have been found also in protists like ciliates and amoebae. The present work describes a new bacterial endosymbiont, "Candidatus Fokinia solitaria", retrieved from three different strains of a novel Paramecium species isolated from a wastewater treatment plant in Rio de Janeiro (Brazil. Symbionts were characterized through the full-cycle rRNA approach: SSU rRNA gene sequencing and fluorescence in situ hybridization (FISH with three species-specific oligonucleotide probes. In electron micrographs, the tiny rod-shaped endosymbionts (1.2 x 0.25-0.35 μm in size were not surrounded by a symbiontophorous vacuole and were located in the peripheral host cytoplasm, stratified in the host cortex in between the trichocysts or just below them. Frequently, they occurred inside autolysosomes. Phylogenetic analyses of Midichloriaceae apparently show different evolutionary pathways within the family. Some genera, such as "Ca. Midichloria" and "Ca. Lariskella", have been retrieved frequently and independently in different hosts and environmental surveys. On the contrary, others, such as Lyticum, "Ca. Anadelfobacter", "Ca. Defluviella" and the presently described "Ca. Fokinia solitaria", have been found only occasionally and associated to specific host species. These last are the only representatives in their own branches thus far. Present data do not allow to infer whether these genera, which we named "stand-alone lineages", are an indication of poorly sampled organisms, thus underrepresented in GenBank, or represent fast evolving, highly adapted evolutionary lineages.

  6. Study on the optimization of stand-alone type photovoltaic systems. 2

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Man Geun; Song, Jin Soo; Kim, Boo ho; Park, I June; Jung, Meung Woong; Yoo, Kyun Joung; Kim, Hong Woo [Korea Inst. of Energy Research, Taejon (Korea, Republic of)

    1995-12-01

    The objectives of this study are to make a maximization of the operating efficiency of photovoltaic power systems, to improve stand- align PV systems design, technical operation and system analysis, and to promote technical cooperation of mutual interest in the area of IEA/PVPS program. This study aims to investigating the problems of applied photovoltaic power systems currently in operation to improve a system design, seeking remedies of individual PVPS applications to improve the system efficiency and reliability and to raise the system economics, and reporting the international movements of PV system dissemination and technical cooperation for developing countries. For the purpose of this works 1) Investigations of applications of existing photovoltaic power systems: - Photovoltaic electric sources used for expressway lamps - Optimum design of solar light with low pressure sodium lamps under 8 hours lighting a day at night by program-able electronic timer. 2) Comparative analyses of Marado PV system and propose a new reliable PV-diesel hybrid system and high efficiency operations. 3) Overall review of Hahwado 60 KWp PV system extending from 25 KWp and the remote monitoring systems for measurement of its operating results. 4) Introduction of IEA/PVPS international cooperating program, especially in task III for stand- alone PV systems and isolated islands and Exco meeting. As results, investigative findings of PVPS currently in operation and the work for improvement - Propose a prescription of Marado PV systems being blocked up by explosion of electrical demands from residence, parallel operational dual inverter with a big capacity. - There are shortage of solar generated power due to shortage of solar cell capacity that results in an increased operating time of diesel generator. Hence the insolation capacity of solar cell per household is continuously increased from the 0.5 KWp to 2 KWp in Hanwado island electrification.

  7. A Low-Power Wearable Stand-Alone Tongue Drive System for People With Severe Disabilities.

    Science.gov (United States)

    Jafari, Ali; Buswell, Nathanael; Ghovanloo, Maysam; Mohsenin, Tinoosh

    2018-02-01

    This paper presents a low-power stand-alone tongue drive system (sTDS) used for individuals with severe disabilities to potentially control their environment such as computer, smartphone, and wheelchair using their voluntary tongue movements. A low-power local processor is proposed, which can perform signal processing to convert raw magnetic sensor signals to user-defined commands, on the sTDS wearable headset, rather than sending all raw data out to a PC or smartphone. The proposed sTDS significantly reduces the transmitter power consumption and subsequently increases the battery life. Assuming the sTDS user issues one command every 20 ms, the proposed local processor reduces the data volume that needs to be wirelessly transmitted by a factor of 64, from 9.6 to 0.15 kb/s. The proposed processor consists of three main blocks: serial peripheral interface bus for receiving raw data from magnetic sensors, external magnetic interference attenuation to attenuate external magnetic field from the raw magnetic signal, and a machine learning classifier for command detection. A proof-of-concept prototype sTDS has been implemented with a low-power IGLOO-nano field programmable gate array (FPGA), bluetooth low energy, battery and magnetic sensors on a headset, and tested. At clock frequency of 20 MHz, the processor takes 6.6 s and consumes 27 nJ for detecting a command with a detection accuracy of 96.9%. To further reduce power consumption, an application-specified integrated circuit processor for the sTDS is implemented at the postlayout level in 65-nm CMOS technology with 1-V power supply, and it consumes 0.43 mW, which is 10 lower than FPGA power consumption and occupies an area of only 0.016 mm.

  8. Hydrogen-based energy storage unit for stand alone PV systems

    International Nuclear Information System (INIS)

    Labbe, J.

    2006-12-01

    Stand alone systems supplied only by a photovoltaic generator need an energy storage unit to be fully self sufficient. Lead acid batteries are commonly used to store energy because of their low cost, despite several operational constraints. A hydrogen-based energy storage unit (HESU) could be another candidate, including an electrolyser, a fuel cell and a hydrogen tank. However many efforts still need to be carried out for this technology to reach an industrial stage. In particular, market outlets must be clearly identified. The study of small stationary applications (few kW) is performed by numerical simulations. A simulator is developed in the Matlab/Simulink environment. It is mainly composed of a photovoltaic field and a storage unit (lead acid batteries, HESU, or hybrid storage HESU/batteries). The system component sizing is achieved in order to ensure the complete system autonomy over a whole year of operation. The simulator is tested with 160 load profiles (1 kW as a yearly mean value) and three locations (Algeria, France and Norway). Two coefficients are set in order to quantify the correlation between the power consumption of the end user and the renewable resource availability at both daily and yearly scales. Among the tested cases, a limit value of the yearly correlation coefficient came out, enabling to recommend the use of the most adapted storage to a considered case. There are cases for which using HESU instead of lead acid batteries can increase the system efficiency, decrease the size of the photovoltaic field and improve the exploitation of the renewable resource. In addition, hybridization of HESU with batteries always leads to system enhancements regarding its sizing and performance, with an efficiency increase by 10 to 40 % depending on the considered location. The good agreement between the simulation data and field data gathered on real systems enabled the validation of the models used in this study. (author)

  9. Probabilistic modelling and analysis of stand-alone hybrid power systems

    International Nuclear Information System (INIS)

    Lujano-Rojas, Juan M.; Dufo-López, Rodolfo; Bernal-Agustín, José L.

    2013-01-01

    As a part of the Hybrid Intelligent Algorithm, a model based on an ANN (artificial neural network) has been proposed in this paper to represent hybrid system behaviour considering the uncertainty related to wind speed and solar radiation, battery bank lifetime, and fuel prices. The Hybrid Intelligent Algorithm suggests a combination of probabilistic analysis based on a Monte Carlo simulation approach and artificial neural network training embedded in a genetic algorithm optimisation model. The installation of a typical hybrid system was analysed. Probabilistic analysis was used to generate an input–output dataset of 519 samples that was later used to train the ANNs to reduce the computational effort required. The generalisation ability of the ANNs was measured in terms of RMSE (Root Mean Square Error), MBE (Mean Bias Error), MAE (Mean Absolute Error), and R-squared estimators using another data group of 200 samples. The results obtained from the estimation of the expected energy not supplied, the probability of a determined reliability level, and the estimation of expected value of net present cost show that the presented model is able to represent the main characteristics of a typical hybrid power system under uncertain operating conditions. - Highlights: • This paper presents a probabilistic model for stand-alone hybrid power system. • The model considers the main sources of uncertainty related to renewable resources. • The Hybrid Intelligent Algorithm has been applied to represent hybrid system behaviour. • The installation of a typical hybrid system was analysed. • The results obtained from the study case validate the presented model

  10. Feasibility study and energy conversion analysis of stand-alone hybrid renewable energy system

    International Nuclear Information System (INIS)

    Baghdadi, Fazia; Mohammedi, Kamal; Diaf, Said; Behar, Omar

    2015-01-01

    Highlights: • Hybrid stand-alone wind–solar–fossil power system is analyzed. • Measurement data are used to evaluate system performance. • The proposed system can generate about 70% from renewables. • Such a hybrid plant is very promising for remote regions in Algeria. - Abstract: There is a great interest in the development of renewable power technologies in Algeria, and more particularly hybrid concept. The present paper has investigated the performance of hybrid PV–Wind–Diesel–Battery configuration based on hourly measurements of Adrar climate (southern Algeria). Data of global solar radiation, ambient temperature and wind speed for a period of one year have been used. Firstly, the proposed hybrid system has been optimized by means of HOMER software. The optimization process has been carried out taking into account renewable resources potential and energy demand; while maximizing renewable electricity use and fuel saving are the purpose. In the second step, a mathematical model has been developed to ensure efficient energy management on the basis of various operation strategies. The analysis has shown that renewable energy system (PV–Wind) is able to supply about 70% of the demand. Wind power has ranked first with 43% of the annual total electricity production followed by diesel generator (with 31%) while the remaining fraction is being to PV panels. In this context, 69% of the fossil fuel can be saved when using the proposed hybrid configuration instead of the diesel generators that are currently installed in most remote regions in Algeria. Such a concept is very promising to meet the focus of renewable energy program announced in 2011.

  11. Stand alone solution for generation and storage of hydrogen and electric energy

    International Nuclear Information System (INIS)

    Gany, Alon; Elitzur, Shani; Valery

    2015-01-01

    A novel method enabling safe, simple, and controllable production, storage, and use of hydrogen as well as compact electric energy storage and generation via hydrogen- oxygen fuel cells has been developed. The technology indicates, in our opinion, a significant milestone in the search for practical utilization of hydrogen as an alternative energy source. It consists of an original thermal-chemical treatment / activation of aluminum powders to react spontaneously with water to produce hydrogen at regular conditions according to the reaction Al+3H 2 O=Al (OH) 3 +3/2H 2 . Only about 1-2% of lithium, based activator is applied, and any type of water including tap water, sea water and waste water may be used, making the method attractive for variety of applications. 11% of hydrogen compared to the aluminum mass can be obtained, and our experiments reveal 90% reaction yield and more. The technology has a clear advantage over batteries, providing specific electric energy of over 2 kW h/kg Al, 5-10 times greater than that of commonly used lithium-ion batteries. Combined with a fuel cell it may be particularly beneficial for stand-alone electric power generators, where there is no access to the grid. Such applications include emergency generators (e.g., in hospitals), electricity backup systems, and power generation in remote communication posts. Automotive applications may be considered as well. The technology provides green electric energy and quiet operation as well as additional heat energy resulting mainly from the exothermic aluminum-water reaction. (full text)

  12. Stand-alone flat-plate photovoltaic power systems: System sizing and life-cycle costing methodology for Federal agencies

    Science.gov (United States)

    Borden, C. S.; Volkmer, K.; Cochrane, E. H.; Lawson, A. C.

    1984-01-01

    A simple methodology to estimate photovoltaic system size and life-cycle costs in stand-alone applications is presented. It is designed to assist engineers at Government agencies in determining the feasibility of using small stand-alone photovoltaic systems to supply ac or dc power to the load. Photovoltaic system design considerations are presented as well as the equations for sizing the flat-plate array and the battery storage to meet the required load. Cost effectiveness of a candidate photovoltaic system is based on comparison with the life-cycle cost of alternative systems. Examples of alternative systems addressed are batteries, diesel generators, the utility grid, and other renewable energy systems.

  13. prfectBLAST: a platform-independent portable front end for the command terminal BLAST+ stand-alone suite.

    Science.gov (United States)

    Santiago-Sotelo, Perfecto; Ramirez-Prado, Jorge Humberto

    2012-11-01

    prfectBLAST is a multiplatform graphical user interface (GUI) for the stand-alone BLAST+ suite of applications. It allows researchers to do nucleotide or amino acid sequence similarity searches against public (or user-customized) databases that are locally stored. It does not require any dependencies or installation and can be used from a portable flash drive. prfectBLAST is implemented in Java version 6 (SUN) and runs on all platforms that support Java and for which National Center for Biotechnology Information has made available stand-alone BLAST executables, including MS Windows, Mac OS X, and Linux. It is free and open source software, made available under the GNU General Public License version 3 (GPLv3) and can be downloaded at www.cicy.mx/sitios/jramirez or http://code.google.com/p/prfectblast/.

  14. Modeling, design and analysis of a stand-alone hybrid power generation system using solar/urine

    International Nuclear Information System (INIS)

    Wu, Wei; Zhou, Ya-Yan; Lin, Mu-Hsuan; Hwang, Jenn-Jiang

    2013-01-01

    Highlights: • The stand-alone hybrid power system is presented. • The urine-to-hydrogen processor is proposed. • Scenario analysis of the hybrid power dispatching and the urine/solar demands is investigated. • The design, modeling and optimization of the hybrid power system is addressed by Aspen Plus and Matlab. - Abstract: The urine turned to hydrogen as an energy conversion process is integrated into a stand-alone hybrid (PV/FC/battery) power generation system. The optimization and simulation of a new urine-to-hydrogen processor is evaluated in Aspen Plus environment. In our approach, the PV generator aims to reduce urine consumption and the lithium-ion battery can compensate the power gap due to the fuel processing delay. Based on prescribed patterns of solar irradiation and the daily load demand of a 30-persons classroom, scenario analyses of the hybrid power dispatching and operational feasibility is addressed

  15. Enhancement of a stand-alone photovoltaic system's performance: Reduction of soft and hard shading

    Energy Technology Data Exchange (ETDEWEB)

    Lamont, Lisa A.; El Chaar, Lana [Petroleum Institute, Electrical Engineering Department, P.O. Box 2533, Abu Dhabi (United Arab Emirates)

    2011-04-15

    A stand-alone photovoltaic (PV) system is the most promising solution to supply electric power to meet energy demand in isolated locations. This technology can offer an interesting alternative to other currently existing sources of energy. Due to space constraint in the remote offshore oil and gas industry, a stand-alone system is used for cathodic protection, telemetry and valve control. However in such an environment, dust accumulation and bird droppings have been critical issues to the operation of off-grid solar devices. These factors do not only reduce the available power of the modules but also makes the cost of solar devices ineffective since cleaning, especially on well-head towers, is very expensive due to the location. Hence this paper presents two technical solutions that have shown promising results in reducing the impact of these factors. (author)

  16. Direct lateral approach to lumbar fusion is a biomechanically equivalent alternative to the anterior approach: an in vitro study.

    Science.gov (United States)

    Laws, Cory J; Coughlin, Dezba G; Lotz, Jeffrey C; Serhan, Hassan A; Hu, Serena S

    2012-05-01

    A human cadaveric biomechanical study of lumbar mobility before and after fusion and with or without supplemental instrumentation for 5 instrumentation configurations. To determine the biomechanical differences between anterior lumbar interbody fusion (ALIF) and direct lateral interbody fusion (DLIF) with and without supplementary instrumentation. Some prior studies have compared various surgical approaches using the same interbody device whereas others have investigated the stabilizing effect of supplemental instrumentation. No published studies have performed a side-by-side comparison of standard and minimally invasive techniques with and without supplemental instrumentation. Eight human lumbosacral specimens (16 motion segments) were tested in each of the 5 following configurations: (1) intact, (2) with ALIF or DLIF cage, (3) with cage plus stabilizing plate, (4) with cage plus unilateral pedicle screw fixation (PSF), and (5) with cage plus bilateral PSF. Pure moments were applied to induce specimen flexion, extension, lateral bending, and axial rotation. Three-dimensional kinematic responses were measured and used to calculate range of motion, stiffness, and neutral zone. Compared to the intact state, DLIF significantly reduced range of motion in flexion, extension, and lateral bending (P = 0.0117, P = 0.0015, P = 0.0031). Supplemental instrumentation significantly increased fused-specimen stiffness for both DLIF and ALIF groups. For the ALIF group, bilateral PSF increased stiffness relative to stand-alone cage by 455% in flexion and 317% in lateral bending (P = 0.0009 and P < 0.0001). The plate increased ALIF group stiffness by 211% in extension and 256% in axial rotation (P = 0.0467 and P = 0.0303). For the DLIF group, bilateral PSF increased stiffness by 350% in flexion and 222% in extension (P < 0.0001 and P = 0.0008). No differences were observed between ALIF and DLIF groups supplemented with bilateral PSF. Our data support that the direct lateral approach

  17. A review of three stand-alone topical thrombins for surgical hemostasis.

    Science.gov (United States)

    Cheng, Christine M; Meyer-Massetti, Carla; Kayser, Steven R

    2009-01-01

    Topical thrombins are active hemostatic agents that can be used to minimize blood loss during surgery. Before 2007, the only topical thrombins available were derived from bovine plasma. Antibody formation to bovine thrombin and/or factor V, with subsequent risk of cross-reactivity with human factor V, and hemorrhagic complications associated with human factor-V deficiencies have been described in case reports of surgeries in which bovine thrombins were used. This risk is now included in the boxed warning section of the bovine thrombin prescribing information. In 2007 and 2008, 2 new topical thrombins from nonbovine sources received approval for use from the US Food and Drug Administration. The 3 active topical thrombins that are currently marketed are bovine plasma-derived thrombin, human plasma-derived thrombin, and human recombinant thrombin. The purpose of this review was to evaluate the literature on the efficacy and safety of topical thrombins and discuss the pharmacoeconomic considerations associated with their use. PubMed, EMBASE, and International Pharmaceutical Abstracts were searched for relevant papers published in English through October 10,2008, using the terms thrombin, human recombinant thrombin, bovine thrombin, plasma derived thrombin, and topical thrombin. Manufacturer-provided materials were also reviewed. Abstracts and unpublished data, as well as evaluations of sealants, adhesives, glues, and other hemostats that contain thrombin mixed with fibrinogen and other clotting factors, were excluded. Four randomized, double-blind studies involving the active, stand-alone topical thrombins were found. The bovine thrombin involved in these studies was the predecessor to the currently marketed, highly purified bovine formulation. No studies comparing the human products, studies involving the highly purified bovine preparation, or placebo-controlled studies involving bovine thrombin were found. In a Phase III comparison of human recombinant thrombin and

  18. Control strategy of wind turbine based on permanent magnet synchronous generator and energy storage for stand-alone systems

    DEFF Research Database (Denmark)

    Deng, Fujin; Liu, Dong; Chen, Zhe

    2017-01-01

    This paper investigates a variable speed wind turbine based on permanent magnet synchronous generator and a full-scale power converter in a stand-alone system. An energy storage system(ESS) including battery and fuel cell-electrolyzer combination is connected to the DC link of the full-scale power...... converter through the power electronics interface. Wind is the primary power source of the system, the battery and FC-electrolyzer combination is used as a backup and a long-term storage system to provide or absorb power in the stand-alone system, respectively. In this paper, a control strategy is proposed...... for the operation of this variable speed wind turbine in a stand-alone system, where the generator-side converter and the ESS operate together to meet the demand of the loads. This control strategy is competent for supporting the variation of the loads or wind speed and limiting the DC-link voltage of the full...

  19. Sizing, techno-economic and generation management analysis of a stand alone photovoltaic power unit including storage devices

    International Nuclear Information System (INIS)

    Jallouli, Rihab; Krichen, Lotfi

    2012-01-01

    Due to the mismatch between the load demand and the intermittent solar energy, a stand-alone photovoltaic-hydrogen system and an optimal control scheme are designed to maintain the high system efficiency. Based on meteorological and the load demand data, a system sizing technique is proposed to establish the minimum capacity of the system components, which are a photovoltaic (PV) panel, a proton exchange membrane fuel cell (PEMFC), a battery bank and an alkaline electrolyzer (Elz). An accurate energy management scheme that is utilized during power transfer is proposed to meet the economic requirements. Case studies are used to verify the efficiency of the energy management strategy and system sizing technique. Simulation results illustrate a simple solution to the design and processing of stand-alone PV-hydrogen (PV-H 2 ) systems. -- Highlights: ► We study a stand alone PV-hydrogen system comprising renewable devices. ► A PV generator, a battery bank, a fuel cell and an electrolyzer are modeled. ► Power management taking into account the economic arrangement and the operating conditions to ensure energy availability is proposed.

  20. Optimum autonomous stand-alone photovoltaic system design on the basis of energy pay-back analysis

    International Nuclear Information System (INIS)

    Kaldellis, J.K.; Zafirakis, D.; Kondili, E.

    2009-01-01

    Stand-alone photovoltaic (PV) systems comprise one of the most promising electrification solutions for covering the demand of remote consumers. However, such systems are strongly questioned due to extreme life-cycle (LC) energy requirements. For similar installations to be considered as environmentally sustainable, their LC energy content must be compensated by the respective useful energy production, i.e. their energy pay-back period (EPBP) should be found less than their service period. In this context, an optimum sizing methodology is currently developed, based on the criterion of minimum embodied energy. Various energy autonomous stand-alone PV-lead-acid battery systems are examined and two different cases are investigated; a high solar potential area and a medium solar potential area. By considering that the PV-battery (PV-Bat) system's useful energy production is equal to the remote consumer's electricity consumption, optimum cadmium telluride (CdTe) based systems yield the minimum EPBP (15 years). If achieving to exploit the net PV energy production however, the EPBP is found less than 20 years for all PV types. Finally, the most interesting finding concerns the fact that in all cases examined the contribution of the battery component exceeds 27% of the system LC energy requirements, reflecting the difference between grid-connected and stand-alone configurations.

  1. A Case Study of Control and Improved Simplified Swarm Optimization for Economic Dispatch of a Stand-Alone Modular Microgrid

    Directory of Open Access Journals (Sweden)

    Xianyong Zhang

    2018-03-01

    Full Text Available Due to the complex configuration and control framework, the conventional microgrid is not cost-effective for engineering applications with small or medium capacity. A stand-alone modular microgrid with separated AC bus and decentralized control strategy is proposed in this paper. Each module is a self-powered system, which consists of wind and solar power, a storage battery, load and three-port converter. The modules are interconnected by three-port converters to form the microgrid. Characteristics, operation principle, control of the modular microgrid and the three-port converter are analyzed in detail. Distributed storage batteries enable power exchanges among modules to enhance economic returns. Economic dispatch of the stand-alone modular microgrid is a mixed-integer programming problem. A day-ahead operation optimization model including fuel cost, battery operation cost, and power transmission cost is established. Because there are so many constraints, it is difficult to produce a feasible solution and even more difficult to have an improved solution. An improved simplified swarm optimization (iSSO method is therefore proposed. The iSSO scheme designs the new update mechanism and survival of the fittest policy. The experimental results from the demonstration project on DongAo Island reflect the effectiveness of the stand-alone modular microgrid and the economic dispatch strategy based on the iSSO method.

  2. A New Vector Control of Brushless Doubly-Fed Inductor Generator With Transient Current Compensation for Stand-Alone Power Generation Applications

    DEFF Research Database (Denmark)

    Liu, Yi; Xu, Wei; Yu, Kailiang

    2018-01-01

    The stand-alone brushless doubly-fed induction generator (BDFIG) with the conventional control strategies suffers heavily from poor dynamic performance especially under heavy load disturbance. This paper presents a new vector control strategy of BDFIG for stand-alone power generation applications...... control strategies, and the results verify the satisfactory dynamic performance of the proposed strategy....

  3. New control strategy of stand-alone brushless doubly-fed induction generator for supplying unbalanced loads in ship shaft power generation system

    DEFF Research Database (Denmark)

    Liu, Yi; Xu, Wei; Xiong, Fei

    2017-01-01

    The ship shaft power generation system based on a stand-alone brushless doubly-fed induction generator (BDFIG) have demonstrated excellent saving-energy performance. This paper presents a new control scheme of the stand-alone BDFIG for supplying unbalanced loads in the ship shaft power generation...

  4. Time-sequential changes of differentially expressed miRNAs during the process of anterior lumbar interbody fusion using equine bone protein extract, rhBMP-2 and autograft

    Science.gov (United States)

    Chen, Da-Fu; Zhou, Zhi-Yu; Dai, Xue-Jun; Gao, Man-Man; Huang, Bao-Ding; Liang, Tang-Zhao; Shi, Rui; Zou, Li-Jin; Li, Hai-Sheng; Bünger, Cody; Tian, Wei; Zou, Xue-Nong

    2014-03-01

    The precise mechanism of bone regeneration in different bone graft substitutes has been well studied in recent researches. However, miRNAs regulation of the bone formation has been always mysterious. We developed the anterior lumbar interbody fusion (ALIF) model in pigs using equine bone protein extract (BPE), recombinant human bone morphogenetic protein-2 (rhBMP-2) on an absorbable collagen sponge (ACS), and autograft as bone graft substitute, respectively. The miRNA and gene expression profiles of different bone graft materials were examined using microarray technology and data analysis, including self-organizing maps, KEGG pathway and Biological process GO analyses. We then jointly analyzed miRNA and mRNA profiles of the bone fusion tissue at different time points respectively. Results showed that miRNAs, including let-7, miR-129, miR-21, miR-133, miR-140, miR-146, miR-184, and miR-224, were involved in the regulation of the immune and inflammation response, which provided suitable inflammatory microenvironment for bone formation. At late stage, several miRNAs directly regulate SMAD4, Estrogen receptor 1 and 5-hydroxytryptamine (serotonin) receptor 2C for bone formation. It can be concluded that miRNAs play important roles in balancing the inflammation and bone formation.

  5. Methanol production via pressurized entrained flow biomass gasification – Techno-economic comparison of integrated vs. stand-alone production

    International Nuclear Information System (INIS)

    Andersson, Jim; Lundgren, Joakim; Marklund, Magnus

    2014-01-01

    The main objective with this work was to investigate techno-economically the opportunity for integrated gasification-based biomass-to-methanol production in an existing chemical pulp and paper mill. Three different system configurations using the pressurized entrained flow biomass gasification (PEBG) technology were studied, one stand-alone plant, one where the bark boiler in the mill was replaced by a PEBG unit and one with a co-integration of a black liquor gasifier operated in parallel with a PEBG unit. The cases were analysed in terms of overall energy efficiency (calculated as electricity-equivalents) and process economics. The economics was assessed under the current as well as possible future energy market conditions. An economic policy support was found to be necessary to make the methanol production competitive under all market scenarios. In a future energy market, integrating a PEBG unit to replace the bark boiler was the most beneficial case from an economic point of view. In this case the methanol production cost was reduced in the range of 11–18 Euro per MWh compared to the stand-alone case. The overall plant efficiency increased approximately 7%-units compared to the original operation of the mill and the non-integrated stand-alone case. In the case with co-integration of the two parallel gasifiers, an equal increase of the system efficiency was achieved, but the economic benefit was not as apparent. Under similar conditions as the current market and when methanol was sold to replace fossil gasoline, co-integration of the two parallel gasifiers was the best alternative based on received IRR. - Highlights: • Techno-economic results regarding integration of methanol synthesis processes in a pulp and paper mill are presented. • The overall energy efficiency increases in integrated methanol production systems compared to stand-alone production units. • The economics of the integrated system improves compared to stand-alone alternatives. • Tax

  6. Stand-Alone Personalized Normative Feedback for College Student Drinkers: A Meta-Analytic Review, 2004 to 2014.

    Directory of Open Access Journals (Sweden)

    Keri B Dotson

    Full Text Available Norms clarification has been identified as an effective component of college student drinking interventions, prompting research on norms clarification as a single-component intervention known as Personalized Normative Feedback (PNF. Previous reviews have examined PNF in combination with other components but not as a stand-alone intervention.To investigate the degree to which computer-delivered stand-alone personalized normative feedback interventions reduce alcohol consumption and alcohol-related harms among college students and to compare gender-neutral and gender-specific PNF.Electronic databases were searched systematically through November 2014. Reference lists were reviewed manually and forward and backward searches were conducted.Outcome studies that compared computer-delivered, stand-alone PNF intervention with an assessment only, attention-matched, or active treatment control and reported alcohol use and harms among college students.Between-group effect sizes were calculated as the standardized mean difference in change scores between treatment and control groups divided by pooled standard deviation. Within-group effect sizes were calculated as the raw mean difference between baseline and follow-up divided by pooled within-groups standard deviation.Eight studies (13 interventions with a total of 2,050 participants were included. Compared to control participants, students who received gender-neutral (dbetween = 0.291, 95% CI [0.159, 0.423] and gender-specific PNF (dbetween = 0.284, 95% CI [0.117, 0.451] reported greater reductions in drinking from baseline to follow-up. Students who received gender-neutral PNF reported 3.027 (95% CI [2.171, 3.882] fewer drinks per week at first follow-up and gender-specific PNF reported 3.089 (95% CI [0.992, 5.186] fewer drinks. Intervention effects were small for harms (dbetween = 0.157, 95% CI [0.037, 0.278].Computer-delivered PNF is an effective stand-alone approach for reducing college student

  7. Stand-Alone Personalized Normative Feedback for College Student Drinkers: A Meta-Analytic Review, 2004 to 2014.

    Science.gov (United States)

    Dotson, Keri B; Dunn, Michael E; Bowers, Clint A

    2015-01-01

    Norms clarification has been identified as an effective component of college student drinking interventions, prompting research on norms clarification as a single-component intervention known as Personalized Normative Feedback (PNF). Previous reviews have examined PNF in combination with other components but not as a stand-alone intervention. To investigate the degree to which computer-delivered stand-alone personalized normative feedback interventions reduce alcohol consumption and alcohol-related harms among college students and to compare gender-neutral and gender-specific PNF. Electronic databases were searched systematically through November 2014. Reference lists were reviewed manually and forward and backward searches were conducted. Outcome studies that compared computer-delivered, stand-alone PNF intervention with an assessment only, attention-matched, or active treatment control and reported alcohol use and harms among college students. Between-group effect sizes were calculated as the standardized mean difference in change scores between treatment and control groups divided by pooled standard deviation. Within-group effect sizes were calculated as the raw mean difference between baseline and follow-up divided by pooled within-groups standard deviation. Eight studies (13 interventions) with a total of 2,050 participants were included. Compared to control participants, students who received gender-neutral (dbetween = 0.291, 95% CI [0.159, 0.423]) and gender-specific PNF (dbetween = 0.284, 95% CI [0.117, 0.451]) reported greater reductions in drinking from baseline to follow-up. Students who received gender-neutral PNF reported 3.027 (95% CI [2.171, 3.882]) fewer drinks per week at first follow-up and gender-specific PNF reported 3.089 (95% CI [0.992, 5.186]) fewer drinks. Intervention effects were small for harms (dbetween = 0.157, 95% CI [0.037, 0.278]). Computer-delivered PNF is an effective stand-alone approach for reducing college student drinking and

  8. An optimized Fuzzy Logic Controller by Water Cycle Algorithm for power management of Stand-alone Hybrid Green Power generation

    International Nuclear Information System (INIS)

    Sarvi, Mohammad; Avanaki, Isa Nasiri

    2015-01-01

    Highlights: • A new method to improve the performance of renewable power management is proposed. • The proposed method is based on Fuzzy Logic optimized by the Water Cycle Algorithm. • The proposed method characteristics are compared with two other methods. • The comparisons confirm that the proposed method is robust and effectiveness one. - Abstract: This paper aims to improve the power management system of a Stand-alone Hybrid Green Power generation based on the Fuzzy Logic Controller optimized by the Water Cycle Algorithm. The proposed Stand-alone Hybrid Green Power consists of wind energy conversion and photovoltaic systems as primary power sources and a battery, fuel cell, and Electrolyzer as energy storage systems. Hydrogen is produced from surplus power generated by the wind energy conversion and photovoltaic systems of Stand-alone Hybrid Green Power and stored in the hydrogen storage tank for fuel cell later using when the power generated by primary sources is lower than load demand. The proposed optimized Fuzzy Logic Controller based power management system determines the power that is generated by fuel cell or use by Electrolyzer. In a hybrid system, operation and maintenance cost and reliability of the system are the important issues that should be considered in studies. In this regard, Water Cycle Algorithm is used to optimize membership functions in order to simultaneously minimize the Loss of Power Supply Probability and operation and maintenance. The results are compared with the particle swarm optimization and the un-optimized Fuzzy Logic Controller power management system to prove that the proposed method is robust and effective. Reduction in Loss of Power Supply Probability and operation and maintenance, are the most advantages of the proposed method. Moreover the level of the State of Charge of the battery in the proposed method is higher than other mentioned methods which leads to increase battery lifetime.

  9. Hierarchical energy management system for stand-alone hybrid system based on generation costs and cascade control

    International Nuclear Information System (INIS)

    Torreglosa, J.P.; García, P.; Fernández, L.M.; Jurado, F.

    2014-01-01

    Highlights: • We present an energy management system for a stand-alone WT/PV/hydrogen/battery hybrid system. • Hierarchical control composed by master and slave control strategies. • Control assures reliable electricity support for stand-alone applications subject to technical and economic criteria. - Abstract: This paper presents an energy management system (EMS) for stand-alone hybrid systems composed by photovoltaic (PV) solar panels and a wind turbine (WT) as primary energy sources and two energy storage systems, which are a hydrogen system and a battery. The hydrogen system is composed of fuel cell (FC), electrolyzer and hydrogen storage tank. The EMS is a hierarchical control composed by a master control strategy and a slave control strategy. On the one hand, the master control generates the reference powers to meet several premises (such as to satisfy the load power demand, and to maintain the hydrogen tank level and the state of charge (SOC) of the battery between their target margins), taking also into account economic aspects to discriminate between using the battery or hydrogen system. On the other hand, the slave control modifies the reference powers generated by the master control according to the energy sources dynamic limitations, and maintains the DC bus voltage at its reference value. The models, implemented in MATLAB-Simulink environment, have been developed from commercially available components. To check the viability of the proposed EMS, two kinds of simulations were carried out: (1) A long-term simulation of 25 years (expected lifetime of the system) with a sample time of one hour to validate the master control of the EMS; and (2) A short-term simulation with sudden net power variations to validate the slave control of the EMS

  10. Efficiency of the hybrid solar-wind systems for electricity supply to the stand-alone sites

    International Nuclear Information System (INIS)

    Abdullaev, D.A.; Isaev, R.I.

    2000-01-01

    The features of stand-alone sites and principles of their electricity supply is described there is going observation of the works about conditions of production and efficiency of using autonomy wind turbines and photovoltaics. Their unsufficiency is estimated. The advantages of hybrid systems and their realization schemes is described. The advantage of hybrid solar-wind Battery system (HSWBS) on the basis of own researches and the facts of other authors are given. The conception overall discounting cost is developed on HSWBS case. (Author)

  11. Evaluation of a proper controller performance for maximum-power point tracking of a stand-alone PV system

    Energy Technology Data Exchange (ETDEWEB)

    Nafeh, A.E.-S.A.; Fahmy, F.H. [Electronics Research Institute, Cairo (Egypt); El-Zahab, E.M.A. [Cairo University, Giza (Egypt). Faculty of Engineering

    2003-02-01

    In this paper the implementation of a suggested stand-alone PV system, for maximum-power point tracking (MPPT), is carried out. Also, this paper presents a comparative study, through experimental work, between the conventional PI controller and the fuzzy logic controller (FLC) under different atmospheric conditions. The implemented system with both the PI controller and the FLC gives a good maximum-power operation of the PV array, but the tracking capability for different optimum operating points is better and faster for the case of using the FLC compared to the case of using the PI controller. (author)

  12. Evaluation of Coflex interspinous stabilization following decompression compared with decompression and posterior lumbar interbody fusion for the treatment of lumbar degenerative disease: A minimum 5-year follow-up study.

    Science.gov (United States)

    Yuan, Wei; Su, Qing-Jun; Liu, Tie; Yang, Jin-Cai; Kang, Nan; Guan, Li; Hai, Yong

    2017-01-01

    Few studies have compared the clinical and radiological outcomes between Coflex interspinous stabilization and posterior lumbar interbody fusion (PLIF) for degenerative lumbar disease. We compared the at least 5-year clinical and radiological outcomes of Coflex stabilization and PLIF for lumbar degenerative disease. Eighty-seven consecutive patients with lumbar degenerative disease were retrospectively reviewed. Forty-two patients underwent decompression and Coflex interspinous stabilization (Coflex group), 45 patients underwent decompression and PLIF (PLIF group). Clinical and radiological outcomes were evaluated. Coflex subjects experienced less blood loss, shorter hospital stays and shorter operative time than PLIF (all pdisease was higher in the PLIF group, but this did not achieve statistical significance (11.1% vs. 4.8%, p=0.277). Both groups provided sustainable improved clinical outcomes for lumbar degenerative disease through at least 5-year follow-up. The Coflex group had significantly better early efficacy than the PLIF group. Coflex interspinous implantation after decompression is safe and effective for lumbar degenerative disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. GOssTo: a stand-alone application and a web tool for calculating semantic similarities on the Gene Ontology.

    Science.gov (United States)

    Caniza, Horacio; Romero, Alfonso E; Heron, Samuel; Yang, Haixuan; Devoto, Alessandra; Frasca, Marco; Mesiti, Marco; Valentini, Giorgio; Paccanaro, Alberto

    2014-08-01

    We present GOssTo, the Gene Ontology semantic similarity Tool, a user-friendly software system for calculating semantic similarities between gene products according to the Gene Ontology. GOssTo is bundled with six semantic similarity measures, including both term- and graph-based measures, and has extension capabilities to allow the user to add new similarities. Importantly, for any measure, GOssTo can also calculate the Random Walk Contribution that has been shown to greatly improve the accuracy of similarity measures. GOssTo is very fast, easy to use, and it allows the calculation of similarities on a genomic scale in a few minutes on a regular desktop machine. alberto@cs.rhul.ac.uk GOssTo is available both as a stand-alone application running on GNU/Linux, Windows and MacOS from www.paccanarolab.org/gossto and as a web application from www.paccanarolab.org/gosstoweb. The stand-alone application features a simple and concise command line interface for easy integration into high-throughput data processing pipelines. © The Author 2014. Published by Oxford University Press.

  14. SedInConnect: a stand-alone, free and open source tool for the assessment of sediment connectivity

    Science.gov (United States)

    Crema, Stefano; Cavalli, Marco

    2018-02-01

    There is a growing call, within the scientific community, for solid theoretic frameworks and usable indices/models to assess sediment connectivity. Connectivity plays a significant role in characterizing structural properties of the landscape and, when considered in combination with forcing processes (e.g., rainfall-runoff modelling), can represent a valuable analysis for an improved landscape management. In this work, the authors present the development and application of SedInConnect: a free, open source and stand-alone application for the computation of the Index of Connectivity (IC), as expressed in Cavalli et al. (2013) with the addition of specific innovative features. The tool is intended to have a wide variety of users, both from the scientific community and from the authorities involved in the environmental planning. Thanks to its open source nature, the tool can be adapted and/or integrated according to the users' requirements. Furthermore, presenting an easy-to-use interface and being a stand-alone application, the tool can help management experts in the quantitative assessment of sediment connectivity in the context of hazard and risk assessment. An application to a sample dataset and an overview on up-to-date applications of the approach and of the tool shows the development potential of such analyses. The modelled connectivity, in fact, appears suitable not only to characterize sediment dynamics at the catchment scale but also to integrate prediction models and as a tool for helping geomorphological interpretation.

  15. Improved double integral sliding mode MPPT controller based parameter estimation for a stand-alone photovoltaic system

    International Nuclear Information System (INIS)

    Chatrenour, Nasrin; Razmi, Hadi; Doagou-Mojarrad, Hasan

    2017-01-01

    Highlights: • IDISMC based MPPT algorithm is introduced. • Hurwitz stability theorem is used for switching surface coefficients computation. • GA approach is presented for parameter estimation of the stand-alone PV system. - Abstract: In this paper, an Improved Double Integral Sliding Mode MPPT Controller (IDISMC) for a stand-alone photovoltaic (PV) system is proposed. Performance of a sliding mode controller (SMC) is greatly influenced by the choice of the sliding surface. Switching surface coefficients were selected by the use of Hurwitz stability theorem. The IDISMC not only is robust against parametric and non-parametric uncertainties, but also has a very small steady-state error, thanks to the use of double integral of tracking voltage error in the definition of its sliding surface. For realistic simulation, Genetic Algorithm (GA) method was used to estimate parameters of solar panels model. The validity of the proposed double integral SMC in maximum power point tracking was approved by comparing the simulation results obtained for a sample PV system with the results of other methods.

  16. Economic and Environmental Assessment of a Renewable Stand-Alone Energy Supply System Using Multi-objective Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dohyun; Han, Seulki; Kim, Jiyong Kim [Incheon National University, Incheon (Korea, Republic of)

    2017-06-15

    This study aims to propose a new optimization-based approach for design and analysis of the stand-alone hybrid energy supply system using renewable energy sources (RES). In the energy supply system, we include multiple energy production technologies such as Photovoltaics (PV), Wind turbine, and fossil-fuel-based AC generator along with different types of energy storage and conversion technologies such as battery and inverter. We then select six different regions of Korea to represent various characteristics of different RES potentials and demand profiles. We finally designed and analyzed the optimal RES stand-alone energy supply system in the selected regions using multiobjective optimization (MOOP) technique, which includes two objective functions: the minimum cost and the minimum CO{sub 2} emission. In addition, we discussed the feasibility and expecting benefits of the systems by comparing to conventional systems of Korea. As a result, the region of the highest RES potential showed the possibility to remarkably reduce CO{sub 2} emissions compared to the conventional system. Besides, the levelized cost of electricity (LCOE) of the RES-based energy system is identified to be slightly higher than conventional energy system: 0.35 and 0.46 $/kWh, respectively. However, the total life-cycle emission of CO{sub 2} (LCECO{sub 2}) can be reduced up to 470 gCO{sub 2}/kWh from 490 gCO{sub 2}/kWh of the conventional systems.

  17. Comparison of pulp-mill-integrated hydrogen production from gasified black liquor with stand-alone production from gasified biomass

    International Nuclear Information System (INIS)

    Andersson, E.; Harvey, S.

    2007-01-01

    When gasified black liquor is used for hydrogen production, significant amounts of biomass must be imported. This paper compares two alternative options for producing hydrogen from biomass: (A) pulp-mill-integrated hydrogen production from gasified back liquor; and (B) stand-alone production of hydrogen from gasified biomass. The comparison assumes that the same amount of biomass that is imported in Alternative A is supplied to a stand-alone hydrogen production plant and that the gasified black liquor in Alternative B is used in a black liquor gasification combined cycle (BLGCC) CHP unit. The comparison is based upon equal amounts of black liquor fed to the gasifier, and identical steam and power requirements for the pulp mill. The two systems are compared on the basis of total CO 2 emission consequences, based upon different assumptions for the reference energy system that reflect different societal CO 2 emissions reduction target levels. Ambitions targets are expected to lead to a more CO 2 -lean reference energy system, in which case hydrogen production from gasified black liquor (Alternative A) is best from a CO 2 emissions' perspective, whereas with high CO 2 emissions associated with electricity production, hydrogen from gasified biomass and electricity from gasified black liquor (Alternative B) is preferable. (author)

  18. Multi-objective optimal planning of the stand-alone microgrid system based on different benefit subjects

    International Nuclear Information System (INIS)

    Guo, Li; Wang, Nan; Lu, Hai; Li, Xialin; Wang, Chengshan

    2016-01-01

    As an important means to realize the energetic complementarity and improve the efficiency of renewable resources, the stand-alone microgrid (SAMG) system gains attention increasingly, especially in islands and remote areas. In this paper, considering the interest conflict of the distribution company and the distributed generation owner, a new multi-objective optimal planning model is formulated for medium voltage SAMG. Besides, to avoid the power constraint of distributed generation (DG) once the over-limit voltage occurs, a novel two-step power dispatch control method including the voltage regulation strategy is proposed, in which the absorption of distributed power by energy storage system (ESS) and the reactive power adjustment though its power control system are used to regulate voltage. The goal of this paper is to search the Pareto-optimal front of the site and capacity of DG as well as the contract price between both parties, and thus can provide effective references for practical planning of SAMG. Considering the high cost of ESS, the investment analysis of ESS is also discussed in the paper. - Highlights: • A multi-objective planning model based on different benefit subjects is proposed. • A two-step power dispatch method including the voltage regulation is proposed. • The economical efficiency of the proposed model is analyzed. • The effective reference for the stand-alone microgrid planning is provided.

  19. A Control Approach and Supplementary Controllers for a Stand-Alone System with Predominance of Wind Generation

    Directory of Open Access Journals (Sweden)

    Tiago Lukasievicz

    2018-02-01

    Full Text Available This paper proposes a control approach and supplementary controllers for the operation of a hybrid stand-alone system composed of a wind generation unit and a conventional generation unit based on synchronous generator (CGU. The proposed controllers allow the islanded or isolated operation of small power systems with predominance of wind generation. As an advantage and a paradigm shift, the DC-link voltage of the wind unit is controlled by means of a conventional synchronous generator connected to the AC grid of the system. Two supplementary controllers, added to a diesel generator (DIG and to a DC dump load (DL, are proposed to control the DC-link voltage. The wind generation unit operates in V-f control mode and the DIG operates in PQ control mode, which allows the stand-alone system to operate either in wind-diesel (WD mode or in wind-only (WO mode. The strong influence of the wind turbine speed variations in the DC-link voltage is mitigated by a low-pass filter added to the speed control loop of the wind turbine. The proposed control approach does not require the use battery bank and ultra-capacitor to control the DC-link voltage in wind generation units based on fully rated converter.

  20. Optimization of the photovoltaic-hydrogen supply system of a stand-alone remote-telecom application

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Guillermo; Martinez, Graciano; Galvez, Jose L.; Cuevas, Raquel; Maellas, Jesus [National Institute for Aerospace Technology (INTA), Renewable Energy Department, Ctra. Ajalvir km 4, E-28850 Torrejon de Ardoz, Madrid (Spain); Gila, Raul; Bueno, Emilio [Polytechnical School - Alcala de Henares University, Electronics Department, Campus Universitario, Ctra. De Madrid-Barcelona Km 33.600, Alcala de Henares, Madrid (Spain)

    2009-07-15

    Hydrogen is considered as the optimal carrier for the surplus energy storage from renewable resources. Although hydrogen and its application in fuel cell is considered as a high-cost energy system, some cost-efficient solutions have been found for their use in stand-alone applications, which usually depend on the variability of renewable sources that have to be oversized in order to reduce their dependence on external energy sources. This paper shows the results from the simulation of several alternatives of introducing hydrogen technologies to increase the independence of a remote-telecom application fed by photovoltaic panels. Hydrogen is obtained by electrolysis and it is used in a fuel cell when the renewable energy source is not enough to maintain the stand-alone application. TRNSYS simulation environment has been used for evaluating the proposed alternatives. The results show that the best configuration option is that considering the use of hydrogen as a way to storage the surplus of radiation and the management system can vary the number of photovoltaic panels assigned to feed the hydrogen generation, the batteries or the telecom application. (author)

  1. Human microRNA target analysis and gene ontology clustering by GOmir, a novel stand-alone application.

    Science.gov (United States)

    Roubelakis, Maria G; Zotos, Pantelis; Papachristoudis, Georgios; Michalopoulos, Ioannis; Pappa, Kalliopi I; Anagnou, Nicholas P; Kossida, Sophia

    2009-06-16

    microRNAs (miRNAs) are single-stranded RNA molecules of about 20-23 nucleotides length found in a wide variety of organisms. miRNAs regulate gene expression, by interacting with target mRNAs at specific sites in order to induce cleavage of the message or inhibit translation. Predicting or verifying mRNA targets of specific miRNAs is a difficult process of great importance. GOmir is a novel stand-alone application consisting of two separate tools: JTarget and TAGGO. JTarget integrates miRNA target prediction and functional analysis by combining the predicted target genes from TargetScan, miRanda, RNAhybrid and PicTar computational tools as well as the experimentally supported targets from TarBase and also providing a full gene description and functional analysis for each target gene. On the other hand, TAGGO application is designed to automatically group gene ontology annotations, taking advantage of the Gene Ontology (GO), in order to extract the main attributes of sets of proteins. GOmir represents a new tool incorporating two separate Java applications integrated into one stand-alone Java application. GOmir (by using up to five different databases) introduces miRNA predicted targets accompanied by (a) full gene description, (b) functional analysis and (c) detailed gene ontology clustering. Additionally, a reverse search initiated by a potential target can also be conducted. GOmir can freely be downloaded BRFAA.

  2. The SNAP trial: a double blind multi-center randomized controlled trial of a silicon nitride versus a PEEK cage in transforaminal lumbar interbody fusion in patients with symptomatic degenerative lumbar disc disorders: study protocol

    Science.gov (United States)

    2014-01-01

    Background Polyetheretherketone (PEEK) cages have been widely used in the treatment of lumbar degenerative disc disorders, and show good clinical results. Still, complications such as subsidence and migration of the cage are frequently seen. A lack of osteointegration and fibrous tissues surrounding PEEK cages are held responsible. Ceramic implants made of silicon nitride show better biocompatible and osteoconductive qualities, and therefore are expected to lower complication rates and allow for better fusion. Purpose of this study is to show that fusion with the silicon nitride cage produces non-inferior results in outcome of the Roland Morris Disability Questionnaire at all follow-up time points as compared to the same procedure with PEEK cages. Methods/Design This study is designed as a double blind multi-center randomized controlled trial with repeated measures analysis. 100 patients (18–75 years) presenting with symptomatic lumbar degenerative disorders unresponsive to at least 6 months of conservative treatment are included. Patients will be randomly assigned to a PEEK cage or a silicon nitride cage, and will undergo a transforaminal lumbar interbody fusion with pedicle screw fixation. Primary outcome measure is the functional improvement measured by the Roland Morris Disability Questionnaire. Secondary outcome parameters are the VAS leg, VAS back, SF-36, Likert scale, neurological outcome and radiographic assessment of fusion. After 1 year the fusion rate will be measured by radiograms and CT. Follow-up will be continued for 2 years. Patients and clinical observers who will perform the follow-up visits will be blinded for type of cage used during follow-up. Analyses of radiograms and CT will be performed independently by two experienced radiologists. Discussion In this study a PEEK cage will be compared with a silicon nitride cage in the treatment of symptomatic degenerative lumbar disc disorders. To our knowledge, this is the first randomized controlled

  3. Study on Soft Phase Locked Method to Solving the Synchronization Problem of Active Power Filter in Stand-alone Power Grid

    DEFF Research Database (Denmark)

    Zhuo, Fang; Wu, Longhui; Chen, Zhe

    2009-01-01

    on zero-cross detection can't work effectively in small rating stand-alone power grid. Then a soft phase locked loop with additional filter is proposed. It can lock the phase angle on to the positive sequence of fundamental voltage accurately and rapidly. It ensures the performance of APF applied...... in the small rating stand-alone power grid. Moreover, the soft phase locked loop is easy to be implemented in a Digital Signal Processor (DSP). Simulation and experimental results validate that the soft phase locked loop has satisfactory performance.......Traditional LC filters can't work stably in small rating stand-alone power grid. So active power filter (APF) is becoming an important tool to solve the power quality problem in small rating stand-alone power grid. In most current detection algorithm of APF, it needs a synchronizing signal. Firstly...

  4. Online retrieval of patient information by asynchronous communication between general purpose computer and stand-alone personal computer

    International Nuclear Information System (INIS)

    Tsutsumi, Reiko; Takahashi, Kazuei; Sato, Toshiko; Komatani, Akio; Yamaguchi, Koichi

    1988-01-01

    Asynchronous communication was made between host (FACOM M-340) and personal computer (OLIBETTIE S-2250) to get patient's information required for RIA test registration. The retrieval system consists of a keyboad input of six numeric codes, patient's ID, and a real time reply containing six parameters for the patient. Their identified parameters are patient's name, sex, date of birth (include area), department, and out- or inpatient. Linking this program to RIA registration program for individual patient, then, operator can input name of RIA test requested. Our simple retrieval program made a useful data network between different types of host and stand-alone personal computers, and enabled us accurate and labor-saving registration for RIA test. (author)

  5. Integration of hydrogen energy technologies in stand-alone power systems analysis of the current potential for applications

    International Nuclear Information System (INIS)

    Zoulias, E.I.; Lymberopoulos, N.; Tsoutsos, T.; Glockner, R.; Mydske, H.J.; Vosseler, I.; Gavalda, O.; Taylor, P.

    2006-01-01

    The European study entitled: 'Market Potential Analysis for Introduction of Hydrogen Energy Technology in Stand-Alone Power Systems (H-SAPS)' aimed to establish a broad understanding of the market potential for H-SAPS and provide a basis for promoting in wide scale new technological applications. The scope of the study was limited to small and medium installations, up to a few hundred kW power rating and based on RE as the primary energy source. The potential for hydrogen technology in SAPS was investigated through an assessment of the technical potential for hydrogen, the market analysis and the evaluation of external factors. The results are mostly directed towards action by governments and the research community but also industry involvement is identified. The results include targeted market research, establishment of individual cost targets, regulatory changes to facilitate alternative grid solutions, information and capacity building, focused technology research and bridging the technology gaps. (author)

  6. A soil-canopy scheme for use in a numerical model of the atmosphere: 1D stand-alone model

    Science.gov (United States)

    Kowalczyk, E. A.; Garratt, J. R.; Krummel, P. B.

    We provide a detailed description of a soil-canopy scheme for use in the CSIRO general circulation models (GCMs) (CSIRO-4 and CSIRO-9), in the form of a one-dimensional stand-alone model. In addition, the paper documents the model's ability to simulate realistic surface fluxes by comparison with mesoscale model simulations (involving more sophisticated soil and boundary-layer treatments) and observations, and the diurnal range in surface quantities, including extreme maximum surface temperatures. The sensitivity of the model to values of the surface resistance is also quantified. The model represents phase 1 of a longer-term plan to improve the atmospheric boundary layer (ABL) and surface schemes in the CSIRO GCMs.

  7. Risk factors for intervertebral instability assessed by temporal evaluation of the radiographs and reconstructed computed tomography images after L5-S1 single-level transforaminal interbody fusion: A retrospective study.

    Science.gov (United States)

    Kobayashi, Yoshiomi; Shinozaki, Yoshio; Takahashi, Yohei; Takaishi, Hironari; Ogawa, Jun

    2017-01-01

    Intervertebral instability risks following L5-S1 transforaminal lumbar interbody fusion (TLIF) and causes of bony bridge formation on computed tomography (CT) remain largely unknown. We evaluated the temporal changes on plain radiographs and reconstructed CT images from 178 patients who had undergone single-level L5-S1 TLIF between February 2011 and February 2015. We statistically analyzed temporal changes the L5-S1 angle on radiographs and intervertebral stability (IVS) at the last observation. Bony bridge formation between the L5-S1 vertebral bodies and the titanium cage subsidence were analyzed by using reconstructed CT. Preoperative L5-S1 angle in the non-IVS group was significantly greater than that in the IVS group. The cage subsidence was classified as follows: type A, both upper and lower endplates; type B, either endplate; or type C, no subsidence. Types B and C decreased over time, whereas type A increased after surgery. The bony bridges between vertebral bodies were found in 87.2% of patients, and 94.5% of all bony bridges were found only in the cage, not on the contralateral side. Our findings suggested that high preoperative L5-S1 angle increased the risk of intervertebral instability after TLIF. The L5-S1 angle decreased over time with increasing type A subsidence, and almost all bony bridges were found only in the cage. These results suggest that the vertebral bodies were stabilized because of cage subsidence, and final bony bridges were created. Methods to improve bony bridge creation are needed to obtain reliable L5-S1 intervertebral bone union. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Leadership in Dental Hygiene Degree Completion Programs: A Pilot Study Comparing Stand-Alone Leadership Courses and Leadership-Infused Curricula.

    Science.gov (United States)

    Smith, Michelle L; Gurenlian, JoAnn R; Freudenthal, Jacqueline J; Farnsworth, Tracy J

    2016-05-01

    The aim of this study was to define the extent to which leadership and leadership skills are taught in dental hygiene degree completion programs by comparing stand-alone leadership courses/hybrid programs with programs that infuse leadership skills throughout the curricula. The study involved a mixed-methods approach using qualitative and quantitative data. Semi-structured interviews were conducted with program directors and faculty members who teach a stand-alone leadership course, a hybrid program, or leadership-infused courses in these programs. A quantitative comparison of course syllabi determined differences in the extent of leadership content and experiences between stand-alone leadership courses and leadership-infused curricula. Of the 53 U.S. dental hygiene programs that offer degree completion programs, 49 met the inclusion criteria, and 19 programs provided course syllabi. Of the program directors and faculty members who teach a stand-alone leadership course or leadership-infused curriculum, 16 participated in the interview portion of the study. The results suggested that competencies related to leadership were not clearly defined or measurable in current teaching. Reported barriers to incorporating a stand-alone leadership course included overcrowded curricula, limited qualified faculty, and lack of resources. The findings of this study provide a synopsis of leadership content and gaps in leadership education for degree completion programs. Suggested changes included defining a need for leadership competencies and providing additional resources to educators such as courses provided by the American Dental Education Association and the American Dental Hygienists' Association.

  9. Stand-alone microgrids

    NARCIS (Netherlands)

    Bauer, P.; Weldemariam, L.E.; Raijen, E.

    2011-01-01

    Abstract- A hybrid power system (HPS) which consists of diesel Genset, PV -arrays and wind turbines with energy storing and power electronic devices is discussed in this paper. An inventory of different connection topologies is made for some of the sources that generate AC power and others that

  10. Epicardial, Biatrial Ablation With Integrated Uni-bipolar Radiofrequency Technology in Stand-alone Persistent Atrial Fibrillation.

    Science.gov (United States)

    Rosati, Fabrizio; Muneretto, Claudio; Merati, Elisa; Polvani, Gianluca; Moltrasio, Massimo; Tondo, Claudio; Curnis, Antonio; Cerini, Manuel; Metras, Alexandre; Bisleri, Gianluigi

    Although minimally invasive approaches for surgical treatment of stand-alone atrial fibrillation have gained popularity for the past decade, ablation technology and extensive lesion sets play a major role in the achievement of a successful procedure, especially in presence of persistent and long-standing persistent atrial fibrillation. We evaluated clinical outcomes after totally endoscopic biatrial epicardial ablation of persistent atrial fibrillation with a novel integrated uni-bipolar radiofrequency device. Forty-nine (49) consecutive patients with stand-alone atrial fibrillation underwent right-sided monolateral thoracoscopic surgical ablation with a novel integrated uni-bipolar radiofrequency energy delivery and temperature-controlled technology. Atrial fibrillation was persistent in 13 (26.5%) of 49 and long-standing persistent in 36 (73.5%) of 49 patients. Mean ± SD age was 60.6 ± 10.3 years. Median duration of atrial fibrillation was 74 months. Mean ± SD left atrial diameter was 44.7 ± 4.0 mm. Epicardial en bloc isolation of all pulmonary veins (box lesion) and additional ablation of the right atrial free wall was successfully performed via minimally invasive approach without any intraoperative and postoperative major complications. Intraoperative entrance and exit block was achieved in 77.5% (38/49) and 91.8% (45/49) of patients, respectively. Mean ± SD ablation time was 16.3 ± 4.8 minutes. No intensive care unit stay was required. Postoperative sinus rhythm was achieved in 93.8% (30/32) patients, and no pacemaker implantation was required. At 13 months, 87.7% (43/49) of patients were in sinus rhythm; 71.4% (35/49) were free from antiarrhythmic drugs and 75.5% (37/49) from oral anticoagulation. Integrated uni-bipolar radiofrequency ablation technology showed to be effective for the surgical treatment of atrial fibrillation with a total endoscopic approach. A versapolar suction device with extensive right-left atrial lesion set may further improve

  11. A Novel Method for Fast Configuration of Energy Storage Capacity in Stand-Alone and Grid-Connected Wind Energy Systems

    Directory of Open Access Journals (Sweden)

    Haixiang Zang

    2016-12-01

    Full Text Available In this paper, a novel method is proposed and applied to quickly calculate the capacity of energy storage for stand-alone and grid-connected wind energy systems, according to the discrete Fourier transform theory. Based on practical wind resource data and power data, which are derived from the American Wind Energy Technology Center and HOMER software separately, the energy storage capacity of a stand-alone wind energy system is investigated and calculated. Moreover, by applying the practical wind power data from a wind farm in Fujian Province, the energy storage capacity for a grid-connected wind system is discussed in this paper. This method can also be applied to determine the storage capacity of a stand-alone solar energy system with practical photovoltaic power data.

  12. Development of a Laser-Powered Dielectric Structure-Based Accelerator as a Stand-Alone Particle Source

    International Nuclear Information System (INIS)

    Yoder, R. B.; Travish, G.; Arab, E. R.; Fong, D.; Hoyer, Z.; Lacroix, U. H.; Vartanian, N.; Rosenzweig, J. B.

    2010-01-01

    An experimental program to develop and build a dielectric-based slab-symmetric structure (the micro-accelerator platform, or MAP) for generating and accelerating low-energy electrons is underway at UCLA and Manhattanville College. This optical acceleration structure is effectively a resonant cavity powered by a side-coupled laser, and has applications as a radiation source for medicine or industry. We present recent experimental and computational results on the accelerator, and progress toward its incorporation into a self-contained particle source. Such a particle source would incorporate a micron-scale electron emitter and a non-relativistic capture region to enable self-injection into the synchronous field within the accelerator. A prototype of the accelerator itself has been constructed from candidate dielectric materials using micromanufacturing techniques; the current status of the testing program is described. A novel electron emitter incorporating pyroelectric crystals with field-enhancing tips has been demonstrated to produce steady currents; the results are dependent on tip geometry, and appear suitable for injection into a microstructure. Extension of the MAP concept to non-relativistic velocities, as in the stand-alone source, requires a tapered structure that gives rise to numerous complications including beam defocusing and manufacturing challenges; approaches for addressing these complications are mentioned.

  13. Adaptive Artificial intelligence based fuzzy logic MPPTcontrol for stande-alone photovoltaic system under different atmospheric conditions

    Directory of Open Access Journals (Sweden)

    Zaghba Layachi

    2015-08-01

    Full Text Available there is an increased need for analysing the effect of atmospheric variables on photovoltaic (PV production and performance. The outputs from the different PV cells in different atmospheric conditions, such as irradiation and temperature , differ from each other evidencing knowledge deficiency in PV systems [14]. Maximum power point tracking (MPPT methods are used to maximize the PV array output power by tracking continuously the maximum power point (MPP. Among all MPPT methods existing in the literature, perturb and observe (P&O is the most commonly used for its simplicity and ease of implementation; however, it presents drawbacks such as slow response speed, oscillation around the MPP in steady state, and even tracking in wrong way under rapidly changing atmospheric conditions. In order to allow a functioning around the optimal point Mopt, we have inserted a DC-DC converter (Buck–Boost for a better matching between the PV and the load. This paper, we study the Maximum power point tracking using adaptive Intelligent fuzzy logic and conventional (P&O control for stande-alone photovoltaic Array system .In particular, the performances of the controllers are analyzed under variation weather conditions with are constant temperature and variable irradiation. The proposed system is simulated by using MATLAB-SIMULINK. According to the results, fuzzy logic controller has shown better performance during the optimization.

  14. Stand-alone power systems for the future: Optimal design, operation and control of solar-hydrogen energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Ulleberg, Oeystein

    1999-12-31

    This thesis gives a systematic review of the fundamentals of energy systems, the governing physical and chemical laws related to energy, inherent characteristics of energy system, and the availability of the earth`s energy. It shows clearly why solar-hydrogen systems are one of the most viable options for the future. The main subject discussed is the modelling of SAPS (Stand-Alone Power Systems), with focus on photovoltaic-hydrogen energy systems. Simulation models for a transient simulation program are developed for PV-H{sub 2} components, including models for photovoltaics, water electrolysis, hydrogen storage, fuel cells, and secondary batteries. A PV-H{sub 2} demonstration plant in Juelich, Germany, is studied as a reference plant and the models validated against data from this plant. Most of the models developed were found to be sufficiently accurate to perform short-term system simulations, while all were more than accurate enough to perform long-term simulations. Finally, the verified simulation models are used to find the optimal operation and control strategies of an existing PV-H{sub 2} system. The main conclusion is that the simulation methods can be successfully used to find optimal operation and control strategies for a system with fixed design, and similar methods could be used to find alternative system designs. 148 refs., 78 figs., 31 tabs.

  15. Power fluctuations suppression of stand-alone hybrid generation combining solar photovoltaic/wind turbine and fuel cell systems

    International Nuclear Information System (INIS)

    Ahmed, Nabil A.; Miyatake, Masafumi; Al-Othman, A.K.

    2008-01-01

    In this paper a hybrid energy system combining variable speed wind turbine, solar photovoltaic and fuel cell generation systems is presented to supply continuous power to residential power applications as stand-alone loads. The wind and photovoltaic systems are used as main energy sources while the fuel cell is used as secondary or back-up energy source. Three individual dc-dc boost converters are used to control the power flow to the load. A simple and cost effective control with dc-dc converters is used for maximum power point tracking and hence maximum power extracting from the wind turbine and the solar photovoltaic systems. The hybrid system is sized to power a typical 2 kW/150 V dc load as telecommunication power plants or ac residential power applications in isolated islands continuously throughout the year. The results show that even when the sun and wind are not available; the system is reliable and available and it can supply high-quality power to the load. The simulation results which proved the accuracy of the proposed controllers are given to demonstrate the availability of the proposed system in this paper. Also, a complete description of the management and control system is presented

  16. Comparison of Turkey’s Geographical Regions in terms of Stand-Alone PV System Design and Cost Parameters

    Directory of Open Access Journals (Sweden)

    Nevzat Onat

    2017-01-01

    Full Text Available Stand-alone photovoltaic (SAPV systems are widely used in rural areas where there is no national grid or as a precaution against power outages. In this study, technical and economic analysis of a SAPV system was carried out using meteorological data for 75 province centers in seven geographical regions of Turkey. Obtained results for each province center were separated by geographical area. The averages of the centers for each region are taken as output. A calculation algorithm based on MsExcel has been established for these operations. The analyses made with the developed algorithm are repeated for five different scenarios that they cover periods of time when a constant strong load is active for all seasons (winter, spring, summer, and autumn and all year round. The developed algorithm calculates the life-cycle cost, the unit energy cost, the electrical capacity utilization rate, the amount of generated/excess energy per month, the initial investment/replacement, and operating and maintenance (O&M costs of each element. As a result, geographical regions of Turkey are compared in terms of these outputs graphically. Further investigations may include the sale of excess energy generated, small-scale PV system cost factors parallel to the grid, and the effects of government incentives.

  17. Stand-alone power systems for the future: Optimal design, operation and control of solar-hydrogen energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Ulleberg, Oeystein

    1998-12-31

    This thesis gives a systematic review of the fundamentals of energy systems, the governing physical and chemical laws related to energy, inherent characteristics of energy system, and the availability of the earth`s energy. It shows clearly why solar-hydrogen systems are one of the most viable options for the future. The main subject discussed is the modelling of SAPS (Stand-Alone Power Systems), with focus on photovoltaic-hydrogen energy systems. Simulation models for a transient simulation program are developed for PV-H{sub 2} components, including models for photovoltaics, water electrolysis, hydrogen storage, fuel cells, and secondary batteries. A PV-H{sub 2} demonstration plant in Juelich, Germany, is studied as a reference plant and the models validated against data from this plant. Most of the models developed were found to be sufficiently accurate to perform short-term system simulations, while all were more than accurate enough to perform long-term simulations. Finally, the verified simulation models are used to find the optimal operation and control strategies of an existing PV-H{sub 2} system. The main conclusion is that the simulation methods can be successfully used to find optimal operation and control strategies for a system with fixed design, and similar methods could be used to find alternative system designs. 148 refs., 78 figs., 31 tabs.

  18. Modeling and control design of a stand alone wind energy conversion system based on functional model predictive control

    Energy Technology Data Exchange (ETDEWEB)

    Kassem, Ahmed M. [Beni-Suef University, Electrical Dept., Beni Suef (Egypt)

    2012-09-15

    This paper investigates the application of the model predictive control (MPC) approach to control the voltage and frequency of a stand alone wind generation system. This scheme consists of a wind turbine which drives an induction generator feeding an isolated load. A static VAR compensator is connected at the induction generator terminals to regulate the load voltage. The rotor speed, and thereby the load frequency are controlled via adjusting the mechanical power input using the blade pitch-angle. The MPC is used to calculate the optimal control actions including system constraints. To alleviate computational effort and to reduce numerical problems, particularly in large prediction horizon, an exponentially weighted functional model predictive control (FMPC) is employed. Digital simulations have been carried out in order to validate the effectiveness of the proposed scheme. The proposed controller has been tested through step changes in the wind speed and the load impedance. Simulation results show that adequate performance of the proposed wind energy scheme has been achieved. Moreover, this scheme is robust against the parameters variation and eliminates the influence of modeling and measurement errors. (orig.)

  19. Modeling and Experimental Test of Grid-Tied Photovoltaic Cell Emulating System in the Stand-alone Mode

    Directory of Open Access Journals (Sweden)

    Vu Minh Phap

    2017-06-01

    Full Text Available In recent decades, generation of electricity from solar arrays has been increased to meet the world's growing energy demand. However, the utilization rate of the power conditioner in the grid-tied solar power system is low because the operation of solar panels is dependent on sunlight. Thus, we studied the method that the small scale wind power generating system in size from a few hundred watts to two or three kilowatts can be connected to the grid-tied power conditioner of the solar power system for residential applications with low power ratings (single phase, size is limited to 10kW by emulating characteristic of the solar panel. In this paper, we introduce the application of the grid-tied PV cell emulating system in the stand-alone mode to improve the utilization rate of the power conditioner. The simulation and experimental test results verify that the PV cell emulating system can operate the power conditioner of the gridtied solar power system.

  20. Multi-Objective Optimal Design of Stand-Alone Hybrid Energy System Using Entropy Weight Method Based on HOMER

    Directory of Open Access Journals (Sweden)

    Jiaxin Lu

    2017-10-01

    Full Text Available Implementation of hybrid energy system (HES is generally considered as a promising way to satisfy the electrification requirements for remote areas. In the present study, a novel decision making methodology is proposed to identify the best compromise configuration of HES from a set of feasible combinations obtained from HOMER. For this purpose, a multi-objective function, which comprises four crucial and representative indices, is formulated by applying the weighted sum method. The entropy weight method is employed as a quantitative methodology for weighting factors calculation to enhance the objectivity of decision-making. Moreover, the optimal design of a stand-alone PV/wind/battery/diesel HES in Yongxing Island, China, is conducted as a case study to validate the effectiveness of the proposed method. Both the simulation and optimization results indicate that, the optimization method is able to identify the best trade-off configuration among system reliability, economy, practicability and environmental sustainability. Several useful conclusions are given by analyzing the operation of the best configuration.

  1. First clinical results of minimally invasive vector lumbar interbody fusion (MIS-VLIF) in spondylodiscitis and concomitant osteoporosis: a technical note.

    Science.gov (United States)

    Rieger, Bernhard; Jiang, Hongzhen; Ruess, Daniel; Reinshagen, Clemens; Molcanyi, Marek; Zivcak, Jozef; Tong, Huaiyu; Schackert, Gabriele

    2017-12-01

    First description of MIS-VLIF, a minimally invasive lumbar stabilization, to evaluate its safety and feasibility in patients suffering from weak bony conditions (lumbar spondylodiscitis and/or osteoporosis). After informed consent, 12 patients suffering from lumbar spondylodiscitis underwent single level MIS-VLIF. Eight of them had a manifest osteoporosis, either. Pre- and postoperative clinical status was documented using numeric rating scale (NRS) for leg and back pain. In all cases, the optimal height for the cage was preoperatively determined using software-based range of motion and sagittal balance analysis. CT scans were obtained to evaluate correct placement of the construct and to verify fusion after 6 months. Since 2013, 12 patients with lumbar pyogenic spondylodiscitis underwent MIS-VLIF. Mean surgery time was 169 ± 28 min and average blood loss was less than 400 ml. Postoperative CT scans showed correct placement of the implants. Eleven patients showed considerable postoperative improvement in clinical scores. In one patient, we observed screw loosening. After documented bony fusion in the CT scan, the fixation system was removed in two cases to achieve lower material load. The load-bearing trajectories (vectors) of MIS-VLIF are different from those of conventional coaxial pedicle screw implantation. The dorsally converging construct combines the heads of the dorsoventral pedicle screws with laminar pedicle screws following cortical bone structures within a small approach. In case of lumbar spondylodiscitis and/or osteoporosis, MIS-VLIF relies on cortical bony structures for all screw vectors and the construct does not depend on conventional coaxial pedicle screws in the presence of inflamed, weak, cancellous or osteoporotic bone. MIS-VLIF allows full 360° lumbar fusion including cage implantation via a small, unilateral dorsal midline approach.

  2. Techno-economic analysis of stand-alone photovoltaic/wind/battery/hydrogen systems for very small-scale applications

    Directory of Open Access Journals (Sweden)

    Stojković Saša M.

    2016-01-01

    Full Text Available The paper presents the results of a technical and economic analysis of three stand-alone hybrid power systems based on renewable energy sources which supply a specific group of low-power consumers. This particular case includes measuring sensors and obstacle lights on a meteorological mast for wind measurements requiring an uninterrupted power supply in cold climate conditions. Although these low-power (100 W measuring sensors and obstacle lights use little energy, their energy consumption is not the same as the available solar energy obtained on a daily or seasonal basis. In the paper, complementarity of renewable energy sources was analysed, as well as one of short-term lead-acid battery-based storage and seasonal, hydrogen-based (electrolyser, H2 tank, and fuel cells storage. These relatively complex power systems were proposed earlier for high-power consumers only, while this study specifically highlights the role of the hydrogen system for supplying low-power consumers. The analysis employed a numerical simulation method using the HOMER software tool. The results of the analysis suggest that solar and wind-solar systems, which involve meteorological conditions as referred to in this paper, include a relatively large number of lead-acid batteries. Additionally, the analysis suggests that the use of hydrogen power systems for supplying low power-consumers is entirely justifiable, as it significantly reduces the number of batteries (two at minimum in this particular case. It was shown that the increase in costs induced by the hydrogen system is acceptable.

  3. Energetic and financial investigation of a stand-alone solar-thermal Organic Rankine Cycle power plant

    International Nuclear Information System (INIS)

    Tzivanidis, Christos; Bellos, Evangelos; Antonopoulos, Kimon A.

    2016-01-01

    Highlights: • A stand-alone solar driven Organic Rankine Cycle is optimized parametrically. • The system is optimized energetically and financially. • Nine working fluids are tested with cyclohexane to be the most suitable. • A collecting area of 25,000 m"2 parabolic trough collectors is the optimum solution. • The maximum IRR is 13.46% and the payback period is about 9 years. - Abstract: The use of solar thermal energy for electricity production is a clean and sustainable way to cover the increasing energy needs of our society. The most mature technology for capturing solar energy in high temperature levels is the parabolic trough collectors (PTC). In this study, an Organic Rankine Cycle (ORC) coupled with PTC is analyzed parametrically in order to be optimized financially and energetically. The first step is the thermodynamic investigation of the ORC by using various working fluids. The second step is the energetic and financial investigation of the total system which includes the solar field, the storage tank and the ORC module. By testing many combinations of collecting areas and storage tank volumes, finally cyclohexane proved to be the most suitable working fluid for producing 1 MW_e_l with PTC. Specifically, in the optimum situation a solar field of 25,000 m"2 with storage tank of about 300 m"3 leads to a payback period of 9 years and to an internal rate of return (IRR) equal to 13.46%. Moreover, an economic comparison for different commercial collectors is presented, with Eurotrough ET-150 being the financially optimum solution for this case study.

  4. An adaptive artificial neural network model for sizing stand-alone photovoltaic systems: Application for isolated sites in Algeria

    International Nuclear Information System (INIS)

    Mellit, A.; Benghanem, M.; Hadj Arab, A.; Guessoum, G.

    2004-07-01

    In this paper we investigate, by using an adaptive Artificial Neural Network (ANN), in order to find a suitable model for sizing Stand-Alone Photovoltaic (SAPV) systems, based on a minimum of input data. This model combines Radial Basis Function (RBF) network and Infinite Impulse Response (IIR) filter in order to accelerate the convergence of the network. For the sizing of a photovoltaic (PV) system, we need to determine the optimal sizing coefficients (K PV , K B . These coefficients allow us to determine the number of solar panels and storage batteries necessary to satisfy a given consumption, especially in isolated sites where the global solar radiation data is not always available and which are considered the most important parameters for sizing a PV system. Obtained results by classical models (analytical, numerical, analytical- numerical, B-spline function) and new models like feed-forward (MLP), radial basis function (RBF), MLP-IIR and RBF-IIR have been compared with experimental sizing coefficients in order to illustrate the accuracy of the results of the new developed model. This model has been trained by using 200 known optimal sizing coefficients corresponding to 200 locations in Algeria. In this way, the adaptive model was trained to accept and even handle a number of unusual cases, the unknown validation sizing coefficients set produced very set accurate estimation and a correlation coefficient of 98% was obtained between the calculated and that estimated by the RBF-IIR model. This result indicates that the proposed method can be successfully used for the estimation of optimal sizing coefficients of SAPV systems for any locations in Algeria, but the methodology can be generalized using different locations over the world. (author)

  5. System dynamic model and charging control of lead-acid battery for stand-alone solar PV system

    KAUST Repository

    Huang, B.J.

    2010-05-01

    The lead-acid battery which is widely used in stand-alone solar system is easily damaged by a poor charging control which causes overcharging. The battery charging control is thus usually designed to stop charging after the overcharge point. This will reduce the storage energy capacity and reduce the service time in electricity supply. The design of charging control system however requires a good understanding of the system dynamic behaviour of the battery first. In the present study, a first-order system dynamics model of lead-acid battery at different operating points near the overcharge voltage was derived experimentally, from which a charging control system based on PI algorithm was developed using PWM charging technique. The feedback control system for battery charging after the overcharge point (14 V) was designed to compromise between the set-point response and the disturbance rejection. The experimental results show that the control system can suppress the battery voltage overshoot within 0.1 V when the solar irradiation is suddenly changed from 337 to 843 W/m2. A long-term outdoor test for a solar LED lighting system shows that the battery voltage never exceeded 14.1 V for the set point 14 V and the control system can prevent the battery from overcharging. The test result also indicates that the control system is able to increase the charged energy by 78%, as compared to the case that the charging stops after the overcharge point (14 V). © 2010 Elsevier Ltd. All rights reserved.

  6. Stand-alone front-end system for high- frequency, high-frame-rate coded excitation ultrasonic imaging.

    Science.gov (United States)

    Park, Jinhyoung; Hu, Changhong; Shung, K Kirk

    2011-12-01

    A stand-alone front-end system for high-frequency coded excitation imaging was implemented to achieve a wider dynamic range. The system included an arbitrary waveform amplifier, an arbitrary waveform generator, an analog receiver, a motor position interpreter, a motor controller and power supplies. The digitized arbitrary waveforms at a sampling rate of 150 MHz could be programmed and converted to an analog signal. The pulse was subsequently amplified to excite an ultrasound transducer, and the maximum output voltage level achieved was 120 V(pp). The bandwidth of the arbitrary waveform amplifier was from 1 to 70 MHz. The noise figure of the preamplifier was less than 7.7 dB and the bandwidth was 95 MHz. Phantoms and biological tissues were imaged at a frame rate as high as 68 frames per second (fps) to evaluate the performance of the system. During the measurement, 40-MHz lithium niobate (LiNbO(3)) single-element lightweight (<;0.28 g) transducers were utilized. The wire target measure- ment showed that the -6-dB axial resolution of a chirp-coded excitation was 50 μm and lateral resolution was 120 μm. The echo signal-to-noise ratios were found to be 54 and 65 dB for the short burst and coded excitation, respectively. The contrast resolution in a sphere phantom study was estimated to be 24 dB for the chirp-coded excitation and 15 dB for the short burst modes. In an in vivo study, zebrafish and mouse hearts were imaged. Boundaries of the zebrafish heart in the image could be differentiated because of the low-noise operation of the implemented system. In mouse heart images, valves and chambers could be readily visualized with the coded excitation.

  7. Post-processing in cardiovascular computed tomography. Performance of a client server solution versus a stand-alone solution

    International Nuclear Information System (INIS)

    Luecke, C.; Foldyna, B.; Andres, C.; Grothoff, M.; Nitzsche, S.; Gutberlet, M.; Lehmkuhl, L.; Boehmer-Lasthaus, S.

    2014-01-01

    Purpose: To compare the performance of server-based (CSS) versus stand-alone post-processing software (ES) for the evaluation of cardiovascular CT examinations (cvCT) and to determine the crucial steps. Data of 40 patients (20 patients for coronary artery evaluation and 20 patients prior to transcatheter aortic valve implantation [TAVI]) were evaluated by 5 radiologists with CSS and ES. Data acquisition was performed using a dual-source 128-row CT unit (SOMATOM Definition Flash, Siemens, Erlangen, Germany) and a 64-row CT unit (Brilliance 64, Philips, Hamburg, Germany). The following workflow was evaluated: Data loading, aorta and coronary segmentation, curved multiplanar reconstruction (cMPR) and 3 D volume rendering technique (3D-VRT), measuring of coronary artery stenosis and planimetry of the aortic annulus. The time requirement and subjective quality for the workflow were evaluated. The coronary arteries as well as the TAVI data could be evaluated significantly faster with CSS (5.5 ± 2.9 min and 8.2 ± 4.0 min, respectively) than with ES (13.9 ± 5.2 min and 15.2 ± 10.9 min, respectively, p = 0.01). Segmentation of the aorta (CSS: 1.9 ± 2.0 min, ES: 3.7 ± 3.3 min), generating cMPR of coronaries (CSS: 0.5 ± 0.2 min, ES: 5.1 ± 2.6 min), aorta and iliac vessels (CSS: 0.5 ± 0.4 min and 0.4 ± 0.4 min, respectively, ES: 1.6 ± 0.7 min and 2.8 ± 3 min, respectively) could be performed significantly faster with CSS than with ES with higher quality of cMPR, measuring of coronary stenosis and 3D-VRT (p < 0.05). Evaluation of cvCT can be accomplished significantly faster and better with CSS than with ES. The segmentation remains the most time-consuming workflow step, so optimization of segmentation algorithms could improve performance even further.

  8. Properties of an interspinous fixation device (ISD) in lumbar fusion constructs: a biomechanical study.

    Science.gov (United States)

    Techy, Fernando; Mageswaran, Prasath; Colbrunn, Robb W; Bonner, Tara F; McLain, Robert F

    2013-05-01

    Segmental fixation improves fusion rates and promotes patient mobility by controlling instability after lumbar surgery. Efforts to obtain stability using less invasive techniques have lead to the advent of new implants and constructs. A new interspinous fixation device (ISD) has been introduced as a minimally invasive method of stabilizing two adjacent interspinous processes by augmenting an interbody cage in transforaminal interbody fusion. The ISD is intended to replace the standard pedicle screw instrumentation used for posterior fixation. The purpose of this study is to compare the rigidity of these implant systems when supplementing an interbody cage as used in transforaminal lumbar interbody fusion. An in vitro human cadaveric biomechanical study. Seven human cadaver spines (T12 to the sacrum) were mounted in a custom-designed testing apparatus, for biomechanical testing using a multiaxial robotic system. A comparison of segmental stiffness was carried out among five conditions: intact spine control; interbody spacer (IBS), alone; interbody cage with ISD; IBS, ISD, and unilateral pedicle screws (unilat); and IBS, with bilateral pedicle screws (bilat). An industrial robot (KUKA, GmbH, Augsburg, Germany) applied a pure moment (±5 Nm) in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) through an anchor to the T12 vertebral body. The relative vertebral motion was captured using an optoelectronic camera system (Optotrak; Northern Digital, Inc., Waterloo, Ontario, Canada). The load sensor and the camera were synchronized. Maximum rotation was measured at each level and compared with the intact control. Implant constructs were compared with the control and with each other. A statistical analysis was performed using analysis of variance. A comparison between the intact spine and the IBS group showed no significant difference in the range of motion (ROM) in FE, LB, or AR for the operated level, L3-L4. After implantation of the ISD to augment

  9. A compact seven switches topology and reduced DC-link capacitor size for single-phase stand-alone PV system with hybrid energy storages

    DEFF Research Database (Denmark)

    Liu, Xiong; Wang, Peng; Loh, Poh Chiang

    2011-01-01

    Single-phase stand-alone PV system is suitable for household applications in remote area. Hybrid battery/ultra-capacitor energy storage can reduce charge and discharge cycles and avoid deep discharges of battery. This paper proposes a compact seven switches structure for stand-alone PV system......, which otherwise needs nine switches configuration, inclusive of one switch for boost converter, four switches for single-phase inverter and four switches for two DC/DC converters of battery and ultra-capacitor. It is well-known that a bulky DC-link capacitor is always required to absorb second......-order harmonic current caused by single-phase inverter. In the proposed compact topology, a small size DC-link capacitor can achieve the same function through charging/discharging control of ultra-capacitor to mitigate second-order ripple current. Simulation results are provided to validate the effectiveness...

  10. SoC-Based Output Voltage Control for BESS with a Lithium-Ion Battery in a Stand-Alone DC Microgrid

    Directory of Open Access Journals (Sweden)

    Seung-Yeong Yu

    2016-11-01

    Full Text Available This paper proposes a new DC output voltage control for a battery energy storage system (BESS with a lithium-ion battery based on the state of charge (SoC. The proposed control scheme was verified through computer simulations for a typical stand-alone DC microgrid, which consists of a BESS, photovoltaic (PV panel, engine generator (EG, and DC load. A scaled hardware prototype for a stand-alone DC microgrid was set up in the lab, in which the proposed control scheme was loaded in a DSP controller. The experimental results were compared with the simulation results for performance verification. The proposed control scheme provides relatively lower variation of the DC grid voltage than the conventional droop control.

  11. Systematic Multi-variable H-infinity Control Design for Primary Frequency Regulation in Stand-alone Microgrids with High Penetration of Renewable Energy Sources

    OpenAIRE

    Lam , Quang Linh; Bratcu , Antoneta Iuliana; Riu , Delphine

    2016-01-01

    International audience; In this paper, a systematic design of a robust multi-variable control structure for primary frequency regulation in microgrids with high rate of renewable source penetration is proposed. The considered microgrid represents a diesel-photovoltaic-supercapacitor hybrid power generation system operating in stand-alone mode. The proposed control structure relies on a two-level architecture: classical PI-based current tracking controllers are placed on the low control level ...

  12. Performance of a small stand alone photovoltaic-wind system at El Oyameyo D.F., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Juarez, A.; Campos, J. [Centro de Investigacion en Energia, UNAM, Mexico, D. F. (Mexico); Tiburcio Silver, A. [Instituto Tecnologico de Toluca-Division de Posgrado, Toluca (Mexico)

    1997-12-31

    El Oyameyo, is an ecological site located to the South-West of the Topilejo town, D.F., 19 degree 25` North latitude, 99 degree 5` West longitude and at an altitude of 3100 m. At present, there are 10 families living at this place. They have energy generators to produce their own electricity by means of solar or wind energy using photovoltaic (PV) technology and eolic systems, respectively. There are three different configurations of energy generators: DC regulated PV systems, AC regulated PV systems and one PV-Wind hybrid system. The electrical power installed for the stand alone PV systems are from 48 W-p up to 768 W-p range. Among these, there are 4 PV systems that are configurated in DC regulated systems, and other 6 are AC regulated systems. All these systems use lead-acid battery (scaled or vented) banks to store the energy produced daily by the systems. The PV-Wind hybrid system in formed, at present, by a 5.0 kW wind generator, a PV array of 768 W-p, a 37.8 kW-h storage battery bank and a 5.0 kW DC/AC inverter. In this work, we report the electricity generated, load pattern and overall system performance of the photovoltaic-wind hybrid system. The technical characteristics, energy test on the hybrid system and the experience obtained from energy handling and system maintenance for all the systems are presented. We found that all the systems had shown good performance and users` satisfaction. [Espanol] El Oyameyo es un lugar ecologico localizado al Sur-Oeste del pueblo de Topilejo, D. F., 19 grados 25` de latitud Norte 99 grados 5` de longitud Oeste y a una altitud de 3100m. Actualmente hay 10 familias viviendo en este lugar. Tienen generadores de energia para producir su propia electricidad mediante la energia solar y la del viento usando sistemas fotovoltaicos (FV) y sistemas eolicos, respectivamente. Hay tres diferentes configuraciones de generadores de energia: sistemas fotovoltaicos de CD regulados, sistemas fotovoltaicos de CA regulados y un sistema

  13. Design of a small scale stand-alone solar thermal co-generation plant for an isolated region in Egypt

    International Nuclear Information System (INIS)

    Abdelhady, Suzan; Borello, Domenico; Tortora, Eileen

    2014-01-01

    Highlights: • In the selected area, connection to the grid is very difficult and expensive. • The integrated unsteady CSP/ORC system, was modeled TRNSYS. • Assuming a CSP of 200,000 m 2 , 6 MW e and 21.5 MW th can be obtained. • The energy is sufficient to feed more than 3,300 rural users and two big factories. • PER = 1.43, LCOE = 1.25 USD/kW h and the GHG emissions are reduced of 7300 toe/year. - Abstract: Most of Egypt’s population is concentrated in the Nile Valley (5% of Egypt’s area), while the western desert occupies an area of 50% of the total area of Egypt with a small number of inhabitants. The New Valley is the largest governorates in Egypt which occupies 45.8% of the total area of the Country and 65% of the Western Desert and it is the least densely populated governorate in Egypt. However, New Valley has started to receive the migrated people from the Nile valley and Delta region and the demand for the energy is continuously increasing. However, the rural area in New Valley still suffers from lack of access to energy services. The very high transmission losses and costs are the main challenges for electrification in this area. Then, it is worth to investigate the opportunities for distributed energy generation. This area of Egypt receives some of the highest solar radiation in the world (up to 3000 kW h per square meters per year), making it a prime location for use of this resource. In this study, performance and economic assessment of a small scale stand-alone solar thermal co-generation plant using diathermic oil is presented. This configuration is considered as a promising and sustainable solution to provide electricity and heat to an isolated area satisfying the local loads. Parabolic trough plant has been modeled in TRNSYS simulation environment integrated with the Solar Thermal Electric Components (STEC) model library. Both solar and power cycle performances have been modeled based on the solar energy data of the plant site. The

  14. Performance of a small stand alone photovoltaic-wind system at El Oyameyo D.F., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Juarez, A; Campos, J [Centro de Investigacion en Energia, UNAM, Mexico, D. F. (Mexico); Tiburcio Silver, A [Instituto Tecnologico de Toluca-Division de Posgrado, Toluca (Mexico)

    1998-12-31

    El Oyameyo, is an ecological site located to the South-West of the Topilejo town, D.F., 19 degree 25` North latitude, 99 degree 5` West longitude and at an altitude of 3100 m. At present, there are 10 families living at this place. They have energy generators to produce their own electricity by means of solar or wind energy using photovoltaic (PV) technology and eolic systems, respectively. There are three different configurations of energy generators: DC regulated PV systems, AC regulated PV systems and one PV-Wind hybrid system. The electrical power installed for the stand alone PV systems are from 48 W-p up to 768 W-p range. Among these, there are 4 PV systems that are configurated in DC regulated systems, and other 6 are AC regulated systems. All these systems use lead-acid battery (scaled or vented) banks to store the energy produced daily by the systems. The PV-Wind hybrid system in formed, at present, by a 5.0 kW wind generator, a PV array of 768 W-p, a 37.8 kW-h storage battery bank and a 5.0 kW DC/AC inverter. In this work, we report the electricity generated, load pattern and overall system performance of the photovoltaic-wind hybrid system. The technical characteristics, energy test on the hybrid system and the experience obtained from energy handling and system maintenance for all the systems are presented. We found that all the systems had shown good performance and users` satisfaction. [Espanol] El Oyameyo es un lugar ecologico localizado al Sur-Oeste del pueblo de Topilejo, D. F., 19 grados 25` de latitud Norte 99 grados 5` de longitud Oeste y a una altitud de 3100m. Actualmente hay 10 familias viviendo en este lugar. Tienen generadores de energia para producir su propia electricidad mediante la energia solar y la del viento usando sistemas fotovoltaicos (FV) y sistemas eolicos, respectivamente. Hay tres diferentes configuraciones de generadores de energia: sistemas fotovoltaicos de CD regulados, sistemas fotovoltaicos de CA regulados y un sistema

  15. Posterior lumbar interbody fusion using non resorbable poly-ether-ether-ketone versus resorbable poly-L-lactide-co-D,L-lactide fusion devices. Clinical outcome at a minimum of 2-year follow-up

    NARCIS (Netherlands)

    Jiya, T.U.; Smit, T.H.; van Royen, B.J.; Mullender, M.G.

    2011-01-01

    Previous papers on resorbable poly-L-lactideco-D,L-lactide (PLDLLA) cages in spinal fusion have failed to report adequately on patient-centred clinical outcome measures. Also comparison of PLDLLA cage with a traditionally applicable counterpart has not been previously reported. This is the first

  16. Clinician's perspectives of the relocation of a regional child and adolescent mental health service from co-located to stand alone premises.

    Science.gov (United States)

    Francis, K J; Boyd, C P; Sewell, J; Nurse, S

    2008-01-01

    Australia's National Mental Health Strategy's statement of rights and responsibilities states that children and adolescents admitted to a mental health facility or community program have the right to be separated from adult patients and provided with programs suited to their developmental needs. However, in rural Australia, where a lack of healthcare services, financial constraints, greater service delivery areas and fewer mental healthcare specialists represent the norm, Child and Adolescent Mental Health Services (CAMHS) are sometimes co-located with adult mental health services. The aim of the present study was to evaluate the impact of a recent relocation of a regional CAMHS in Victoria from co-located to stand alone premises. Six CAMHS clinicians who had experienced service delivery at a co-located setting and the current stand-alone CAMHS setting were interviewed about their perceptions of the impact of the relocation on service delivery. An exploratory interviewing methodology was utilized due to the lack of previous research in this area. Interview data were transcribed and analysed according to interpretative phenomenological analysis techniques. Findings indicated a perception that the relocation was positive for clients due to the family-friendly environment at the new setting and separation of CAMHS from adult psychiatric services. However, the impact of the relocation on clinicians was marked by a perceived loss of social capital from adult psychiatric service clinicians. These results provide increased understanding of the effects of service relocation and the influence of co-located versus stand-alone settings on mental health service delivery - an area where little prior research exists.

  17. Factors that can influence the economic feasibility of stand-alone and grid-connected photovoltaic systems: case studies using the software AVES-F

    International Nuclear Information System (INIS)

    Blasques, L.C.M.; Pinho, J.T.

    2004-01-01

    This paper presents case studies of economic feasibility of solar photovoltaic systems using the software AVES-F (Analysis of Economic Feasibility of Photovoltaic Systems), developed by the authors, considering cases of stand-alone and grid-connected systems. The software takes into account several factors that can influence the economic feasibility of these kind of systems, like load to be supplied, distance to the grid, the use regime of the system, applied subsidies and others. The main goal of this paper is to analyze some of these factors and to observe how they can affect the economics of PV systems for electricity generation. (authors)

  18. DCE-MRI of the breast in a stand-alone setting outside a complementary strategy - results of the TK-study

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Clemens G.; Krammer, J.; Wasser, K.; Schoenberg, S.O. [University Medical Centre Mannheim, Medical Faculty Mannheim-University of Heidelberg, Institute of Clinical Radiology and Nuclear Medicine, Mannheim (Germany); Reich, C.; Kaiser, W.A. [Friedrich-Schiller-University Hospital Jena, Institute of Diagnostic and Interventional Radiology I, Jena (Germany); Dietzel, M. [Friedrich-Alexander-University Hospital Erlangen-Nuernberg, Department of Neuroradiology, Erlangen (Germany); Baltzer, P.A.T. [Medical University Vienna, Institute of Radiology and Nuclear Medicine, Vienna (Austria)

    2015-06-01

    To evaluate the accuracy of MRI of the breast (DCE-MRI) in a stand-alone setting with extended indications. According to the inclusion criteria, breast specialists were invited to refer patients to our institution for DCE-MRI. Depending on the MR findings, patients received either a follow-up or biopsy. Between 04/2006 and 12/2011 a consecutive total of 1,488 women were prospectively examined. Of 1,488 included patients, 393 patients were lost to follow-up, 1,095 patients were evaluated. 124 patients were diagnosed with malignancy by DCE-MRI (76 TP, 48 FP, 971 TN, 0 FN cases). Positive cases were confirmed by histology, negative cases by MR follow-ups or patient questionnaires over the next 5 years in 1,737 cases (sensitivity 100 %; specificity 95.2 %; PPV 61.3 %; NPV 100 %; accuracy 95.5 %). For invasive cancers only (DCIS excluded), the results were 63 TP; 27 FP; 971 TP and 0 FN (sensitivity 100 %; specificity 97.2 %; PPV 70 %; NPV 100 %; accuracy 97.5 %). The DCE-MRI indications tested imply that negative results in DCE-MRI reliably exclude cancer. The results were achieved in a stand-alone setting (single modality diagnosis). However, these results are strongly dependent on reader experience and adequate technical standards as prerequisites for optimal diagnoses. (orig.)

  19. DCE-MRI of the breast in a stand-alone setting outside a complementary strategy - results of the TK-study

    International Nuclear Information System (INIS)

    Kaiser, Clemens G.; Krammer, J.; Wasser, K.; Schoenberg, S.O.; Reich, C.; Kaiser, W.A.; Dietzel, M.; Baltzer, P.A.T.

    2015-01-01

    To evaluate the accuracy of MRI of the breast (DCE-MRI) in a stand-alone setting with extended indications. According to the inclusion criteria, breast specialists were invited to refer patients to our institution for DCE-MRI. Depending on the MR findings, patients received either a follow-up or biopsy. Between 04/2006 and 12/2011 a consecutive total of 1,488 women were prospectively examined. Of 1,488 included patients, 393 patients were lost to follow-up, 1,095 patients were evaluated. 124 patients were diagnosed with malignancy by DCE-MRI (76 TP, 48 FP, 971 TN, 0 FN cases). Positive cases were confirmed by histology, negative cases by MR follow-ups or patient questionnaires over the next 5 years in 1,737 cases (sensitivity 100 %; specificity 95.2 %; PPV 61.3 %; NPV 100 %; accuracy 95.5 %). For invasive cancers only (DCIS excluded), the results were 63 TP; 27 FP; 971 TP and 0 FN (sensitivity 100 %; specificity 97.2 %; PPV 70 %; NPV 100 %; accuracy 97.5 %). The DCE-MRI indications tested imply that negative results in DCE-MRI reliably exclude cancer. The results were achieved in a stand-alone setting (single modality diagnosis). However, these results are strongly dependent on reader experience and adequate technical standards as prerequisites for optimal diagnoses. (orig.)

  20. Avaliação clínica radiológica da artrodese lombar transforaminal aberta versus minimamente invasiva Evaluación clínica radiológica de la artrodesis lumbar transforaminal abierta versus mínimamente invasiva Clinical and radiological evaluation of open transforaminal lumbar interbody fusion versus minimally invasive

    Directory of Open Access Journals (Sweden)

    Cristiano Magalhães Menezes

    2009-09-01

    Full Text Available OBJETIVO: a proposta deste trabalho é comparar os resultados clínicos e radiológicos dos pacientes submetidos à artrodese transforaminal aberta e minimamente invasiva. MÉTODOS: quarenta e cinco pacientes foram submetidos à artrodese lombar transforaminal pelo Grupo de Cirurgia Espinhal do Hospital Lifecenter/Ortopédico de Belo Horizonte, no período de Dezembro de 2005 a Maio de 2007, sendo 15 no grupo de artrodese aberta e 30 pacientes do grupo de artrodese minimamente invasiva (MIS. As indicações para a artrodese intersomática foram: doença degenerativa do disco, associada ou não a hérnia de disco ou estenose do canal; espondilolistese de baixo grau espondilolítica ou degenerativa; e síndrome pós-laminectomia/discectomia. As variáveis analisadas foram: tempo de cirurgia, tempo de internação hospitalar, necessidade de hemotransfusão, escala analógica visual de dor (VAS lombar e dos membros inferiores, Oswestry, índice de consolidação da artrodese e retorno ao trabalho. RESULTADOS: o seguimento mínimo foi de 24 meses. Havia oito homens e sete mulheres no Grupo Aberto e 17 homens e 13 mulheres no Grupo MIS. O tempo cirúrgico médio foi de 222 minutos e 221 minutos, respectivamente. Houve melhora significativa da VAS e Oswestry no pós-operatório em ambos os grupos. O tempo de internação hospitalar variou de 3,3 dias para o Grupo Aberto e 1,8 dias para o Grupo MIS. O índice de fusão obtido foi de 93,3% em ambos os grupos. Houve necessidade de hemotransfusão em três pacientes no Grupo Aberto (20% e nenhum caso MIS. CONCLUSÕES: a transforaminal lumbar interbody fusion (TLIF minimamente invasiva apresenta resultados similares em longo prazo quando comparado à TLIF aberta, com os benefícios adicionais de menor morbidade pós-operatória, menor período de internação e reabilitação precoce.OBJETIVO: la propuesta de este trabajo es comparar los resultados clínicos y radiológicos de los pacientes sometidos a la

  1. Techno-economic assessment of FT unit for synthetic diesel production in existing stand-alone biomass gasification plant using process simulation tool

    DEFF Research Database (Denmark)

    Hunpinyo, Piyapong; Narataruksa, Phavanee; Tungkamani, Sabaithip

    2014-01-01

    For alternative thermo-chemical conversion process route via gasification, biomass can be gasified to produce syngas (mainly CO and H2). On more applications of utilization, syngas can be used to synthesize fuels through the catalytic process option for producing synthetic liquid fuels...... such as Fischer-Tropsch (FT) diesel. The embedding of the FT plant into the stand-alone based on power mode plants for production of a synthetic fuel is a promising practice, which requires an extensive adaptation of conventional techniques to the special chemical needs found in a gasified biomass. Because...... there are currently no plans to engage the FT process in Thailand, the authors have targeted that this work focus on improving the FT configurations in existing biomass gasification facilities (10 MWth). A process simulation model for calculating extended unit operations in a demonstrative context is designed...

  2. Effect of State Feedback Coupling and System Delays on the Transient Performance of Stand-Alone VSI with LC Output Filter

    DEFF Research Database (Denmark)

    Federico, de Bosio; de Sousa Ribeiro, Luiz Antonio; Freijedo Fernandez, Francisco Daniel

    2016-01-01

    The influence of state feedback coupling in the dynamics performance of power converters for stand-alone microgrids is investigated. Computation and PWM delays are the main factors that limit the achievable bandwidth of current regulators in digital implementations. In particular, the performance...... of state feedback decoupling is degraded because of these delays. Two decoupling techniques to improve the transient response of the system are investigated, named non-ideal and ideal capacitor voltage decoupling respectively. In particular, the latter solution consists in leading the capacitor voltage...... on the state feedback decoupling path in order to compensate for system delays. Practical implementation issues are discussed with reference to both the decoupling techniques. A design methodology for the voltage loop, that considers the closed loop transfer functions developed for the inner loop, is also...

  3. Synchronized Pulsed dc - dc Converter as Maximum Power Position Tracker with Wide Load and Insolation Variation for Stand Alone PV System

    International Nuclear Information System (INIS)

    Hardik, P. Desai; Ranjan Maheshwari

    2011-01-01

    This paper investigates the interest focused on employing parallel connected dc-dc converter with high tracking effectiveness under wide variation in environmental conditions (Insolation) and wide load variation. dc-dc converter is an essential part of the stand alone PV system. Paper also presents an approach on how duty cycle for maximum power position (MPP) is adjusted by taking care of varying load conditions and without iterative steps. Synchronized PWM pulses are employed for the converter. High tracking efficiency is achieved with continuous input and inductor current. In this approach, the converter can he utilized in buck as well in boost mode. The PV system simulation was verified and experimental results were in agreement to the presented scheme. (authors)

  4. Grid parity analysis of stand-alone hybrid microgrids: A comparative study of Germany, Pakistan, South Africa and the United States

    Science.gov (United States)

    Siddiqui, Jawad M.

    Grid parity for alternative energy resources occurs when the cost of electricity generated from the source is lower than or equal to the purchasing price of power from the electricity grid. This thesis aims to quantitatively analyze the evolution of hybrid stand-alone microgrids in the US, Germany, Pakistan and South Africa to determine grid parity for a solar PV/Diesel/Battery hybrid system. The Energy System Model (ESM) and NREL's Hybrid Optimization of Multiple Energy Resources (HOMER) software are used to simulate the microgrid operation and determine a Levelized Cost of Electricity (LCOE) figure for each location. This cost per kWh is then compared with two distinct estimates of future retail electricity prices at each location to determine grid parity points. Analysis results reveal that future estimates of LCOE for such hybrid stand-alone microgrids range within the 35-55 cents/kWh over the 25 year study period. Grid parity occurs earlier in locations with higher power prices or unreliable grids. For Pakistan grid parity is already here, while Germany hits parity between the years 2023-2029. Results for South Africa suggest a parity time range of the years 2040-2045. In the US, places with low grid prices do not hit parity during the study period. Sensitivity analysis results reveal the significant impact of financing and the cost of capital on these grid parity points, particularly in developing markets of Pakistan and South Africa. Overall, the study helps conclude that variations in energy markets may determine the fate of emerging energy technologies like microgrids. However, policy interventions have a significant impact on the final outcome, such as the grid parity in this case. Measures such as eliminating uncertainty in policies and improving financing can help these grids overcome barriers in developing economies, where they may find a greater use much earlier in time.

  5. Effects of ozone as a stand-alone and coagulation-aid treatment on the reduction of trihalomethanes precursors from high DOC and hardness water.

    Science.gov (United States)

    Sadrnourmohamadi, Mehrnaz; Gorczyca, Beata

    2015-04-15

    This study investigates the effect of ozone as a stand-alone and coagulation aid on the removal of dissolved organic carbon (DOC) from the water with a high level of DOC (13.8 mgL(-1)) and calcium hardness (270 mgL(-1)) CaCO3. Natural water collected from the Assiniboine River (Manitoba, Canada) was used in this study. Effectiveness of ozone treatment was evaluated by measurement of DOC, DOC fractions, UV254, and trihalomethane formation potential (THMFP). Additionally, zeta potential and dissolved calcium concentration were measured to discern the mechanism of ozone reactions. Results indicated that 0.8 mg O3/mg DOC ozone stand-alone can cause up to 86% UV254 reduction and up to 27% DOC reduction. DOC fractionation results showed that ozone can change the composition of DOC in the water samples, converting the hydrophobic fractions into hydrophilic ones and resulting in the reduction of THMFP. Also, ozone caused a decrease in particle stability and dissolved calcium concentration. These simultaneous ozonation effects caused improved water flocculation and enhanced removal of DOC. This resulted in reduction of the coagulant dosage when ozone doses higher than 0.2 mg O3/mg DOC were applied prior to coagulation with ferric sulfate. Also, pre-ozonation-coagulation process achieved preferential THMFP removal for all of the ozone doses tested (0-0.8 mg O3/mg DOC), leading to a lower specific THMFP in pre-ozonated-coagulated waters than in the corresponding ozonated waters. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. PR2ALIGN: a stand-alone software program and a web-server for protein sequence alignment using weighted biochemical properties of amino acids.

    Science.gov (United States)

    Kuznetsov, Igor B; McDuffie, Michael

    2015-05-07

    Alignment of amino acid sequences is the main sequence comparison method used in computational molecular biology. The selection of the amino acid substitution matrix best suitable for a given alignment problem is one of the most important decisions the user has to make. In a conventional amino acid substitution matrix all elements are fixed and their values cannot be easily adjusted. Moreover, most existing amino acid substitution matrices account for the average (dis)similarities between amino acid types and do not distinguish the contribution of a specific biochemical property to these (dis)similarities. PR2ALIGN is a stand-alone software program and a web-server that provide the functionality for implementing flexible user-specified alignment scoring functions and aligning pairs of amino acid sequences based on the comparison of the profiles of biochemical properties of these sequences. Unlike the conventional sequence alignment methods that use 20x20 fixed amino acid substitution matrices, PR2ALIGN uses a set of weighted biochemical properties of amino acids to measure the distance between pairs of aligned residues and to find an optimal minimal distance global alignment. The user can provide any number of amino acid properties and specify a weight for each property. The higher the weight for a given property, the more this property affects the final alignment. We show that in many cases the approach implemented in PR2ALIGN produces better quality pair-wise alignments than the conventional matrix-based approach. PR2ALIGN will be helpful for researchers who wish to align amino acid sequences by using flexible user-specified alignment scoring functions based on the biochemical properties of amino acids instead of the amino acid substitution matrix. To the best of the authors' knowledge, there are no existing stand-alone software programs or web-servers analogous to PR2ALIGN. The software is freely available from http://pr2align.rit.albany.edu.

  7. Influence of prevertebral soft tissue swelling on dysphagia after anterior cervical discectomy and fusion using a rectangular titanium stand-alone cage

    Directory of Open Access Journals (Sweden)

    Toru Yamagata

    2017-01-01

    Conclusions: Although the possible reasons for postoperative dysphagia may not only be multifactorial but also be highly surgeon-dependent, such a complication is still underestimated and needs to be carefully resolved. %PSTS appeared to be easy and reliable index to judge the possible risk of postoperative dysphagia.

  8. Stiffness Matters: Part II - The Effects of Plate Stiffness on Load-Sharing and the Progression of Fusion Following ACDF In Vivo.

    Science.gov (United States)

    Peterson, Joshua M; Chlebek, Carolyn; Clough, Ashley M; Wells, Alexandra K; Batzinger, Kathleen E; Houston, John M; Kradinova, Katerina; Glennon, Joseph C; DiRisio, Darryl J; Ledet, Eric H

    2018-03-19

    Real time in vivo measurement of forces in the cervical spine of goats following anterior cervical discectomy and fusion (ACDF). To measure interbody forces in the cervical spine during the time course of fusion following ACDF with plates of different stiffnesses. Following ACDF, the biomechanics of the arthrodesis is largely dictated by the plate. The properties of the plate prescribe the extent of load-sharing through the disc space versus the extent of stress-shielding. Load-sharing promotes interbody bone formation and stress-shielding can inhibit maturation of bone. However, these principles have never been validated in vivo. Measuring in vivo biomechanics of the cervical spine is critical to understanding the complex relationships between implant design, interbody loading, load-sharing, and the progression of fusion. Anterior cervical plates of distinct bending stiffnesses were placed surgically following ACDF in goats. A validated custom force-sensing interbody implant was placed in the disc space to measure load-sharing in the spine. Interbody loads were measured in vivo in real time during the course of fusion for each plate. Interbody forces during flexion/extension were highly dynamic. In animals that received high stiffness plates, maximum forces were in extension whereas in animals that received lower stiffness plates, maximum forces were in flexion. As fusion progressed, interbody load magnitude decreased. The magnitude of interbody forces in the cervical spine is dynamic and correlates to activity and posture of the head and neck. The magnitude and consistency of forces in the interbody space correlates to plate stiffness with more compliant plates resulting in more consistent load-sharing. The magnitude of interbody forces decreases as fusion matures suggesting that smart interbody implants may be used as a diagnostic tool to indicate the progression of interbody fusion. N/A.

  9. Minimal invasive transforaminal lumbar interbody fusion versus open transforaminal lumbar interbody fusion

    Directory of Open Access Journals (Sweden)

    Arvind G Kulkarni

    2016-01-01

    Conclusion: The results in MI TLIF are comparable with O-TLIF in terms of outcomes. The advantages of MI-TLIF are lesser blood loss, shorter hospital stay, lesser tissue trauma, and early mobilization. The challenges of MI-TLIF lie in the steep learning curve and significant radiation exposure. The ultimate success of TLIF lies in the execution of the procedure, and in this respect the ability to achieve similar results using a minimally invasive technique makes MI-TLIF an attractive alternative.

  10. A practical multi-objective design approach for optimum exhaust heat recovery from hybrid stand-alone PV-diesel power systems

    International Nuclear Information System (INIS)

    Yousefi, Moslem; Kim, Joong Hoon; Hooshyar, Danial; Yousefi, Milad; Sahari, Khairul Salleh Mohamed; Ahmad, Rodina Binti

    2017-01-01

    Highlights: • Heat recovery exchanger is designed based on practical conditions of a hybrid power system. • Off-the-grid electricity system modeling and analysis using micro-grid analysis software HOMER. • NSGA-II is used for the multi-objective design optimization task. • A new local search is proposed to incorporate the engineering knowledge in NSGA-II. • The proposed approach outperforms the existing ones. - Abstract: Integration of solar power and diesel generators (DGs) together with battery storage has proven to be an efficient choice for stand-alone power systems (SAPS). For higher energy efficiency, heat recovery from exhaust gas of the DG can also be employed to supply all or a portion of the thermal energy demand. Although the design of such heat recovery systems (HRSs) has been studied, the effect of solar power integration has not been taken into account. In this paper, a new approach for practical design of these systems based on varying engine loads is presented. Fast and elitist non-dominated sorting genetic algorithm (NSGA-II) equipped with a novel local search was used for the design process, considering conflicting objectives of annual energy recovery and total cost of the system, and six design variables. An integrated power system, designed for a remote SAPS, was used to evaluate the design approach. The optimum power supply system was first designed using the commercial software Hybrid Optimization of Multiple Energy Resources (HOMER), based on power demand and global solar energy in the region. Heat recovery design was based on the outcome of HOMER for DG hourly load, considering different power scenarios. The proposed approach improves the annual heat recovery of the PV/DG/battery system by 4%, PV/battery by 1.7%, and stand-alone DG by 1.8% when compared with a conventional design based on nominal DG load. The results prove that the proposed approach is effective and that load calculations should be taken into account prior to

  11. Custom-Made Titanium 3-Dimensional Printed Interbody Cages for Treatment of Osteoporotic Fracture-Related Spinal Deformity.

    Science.gov (United States)

    Siu, Timothy L; Rogers, Jeffrey M; Lin, Kainu; Thompson, Robert; Owbridge, Mark

    2018-03-01

    Advances in minimally invasive interbody fusion have greatly enhanced surgeons' capability to correct adult spinal deformity with reduced morbidity. However, the feasibility of such approaches is limited in patients with previous osteoporotic fractures as the resultant vertebral deformity renders the end plate geometry incongruous with conventional interbody implants. Current 3-dimensional (3D) printing technology offers a novel solution by fabricating custom-made implants tailored to individual anatomy. We present the results of a patient with osteoporotic lumbar fractures treated by such technology. A 74-year-old woman, with previous osteoporotic fractures at L2 and L3 resulting in concave deformity of the end plates, presented with intractable radiculopathy secondary to lateral recess and foraminal stenosis (L2-3 and L3-4). A minimally invasive lateral lumbar interbody fusion at L2-3 and L3-4 was considered favorable, but due to the associated vertebral collapse, off-the-shelf implants were not compatible with patient anatomy. In silico simulation based on preoperative computed tomography (CT) imaging was thus conducted to design customized cages to cater for the depressed recipient end plates and vertebral loss. The design was converted to implantable titanium cages through 3D additive manufacturing. At surgery, a tight fit between the implants and the targeted disk space was achieved. Postoperative CT scan confirmed excellent implant-end plate matching and restoration of lost disk space. The patient began to ambulate from postoperative day 1 and at 6-month follow-up resolution of radicular symptoms and CT evidence of interbody fusion were recorded. 3D-printed custom-made interbody cages can help overcome the difficulties in deformity correction secondary to osteoporotic fractures. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. The Research on Second-Order ADRC Algorithm of Using Wind Turbine Virtual Inertia to Participate in Primary Frequency Regulation in a Small Stand-Alone Microgrid

    Directory of Open Access Journals (Sweden)

    Wang Yi

    2018-01-01

    Full Text Available In order to improve the transient stability of frequency in a small stand-alone microgrid (SSM, this paper takes a SSM composed of a direct-drive permanent magnet synchronous generator (D-PMSG and a micro gas turbine (MGT as the background and uses wind turbine generator (WTG virtual inertia (VI to participate in the primary (short-term system frequency regulation. First of all, this paper constructs a grid-connected model composed of a WTG and a MGT, analyzes the WTG virtual inertia frequency regulation mechanism, and explains the principle of proportional-differentiation (PD virtual inertia control (VIC and its shortcomings. Secondly, the paper introduces the structure principle of n-order active disturbance rejection control (ADRC and deduces the design process of second-order ADRC-VIC. Finally, through the simulation and experimental verification, comparing the frequency perturbation of without-VIC, PD-VIC, and ADRC-VIC, it is concluded that PD-VIC and ADRC-VIC both can use the WTG virtual inertia to participate in the primary frequency regulation. The frequency regulation effect of ADRC-VIC is better than PD-VIC, ADRC-VIC can extend the rotor speed recovery time and avoid overshoot, and its frequency fluctuation amplitude and settling time are obviously improved, and ADRC-VIC can effectively avoid the overshoot phenomenon of the MGT output power.

  13. Optimal Sizing of a Stand-Alone Hybrid Power System Based on Battery/Hydrogen with an Improved Ant Colony Optimization

    Directory of Open Access Journals (Sweden)

    Weiqiang Dong

    2016-09-01

    Full Text Available A distributed power system with renewable energy sources is very popular in recent years due to the rapid depletion of conventional sources of energy. Reasonable sizing for such power systems could improve the power supply reliability and reduce the annual system cost. The goal of this work is to optimize the size of a stand-alone hybrid photovoltaic (PV/wind turbine (WT/battery (B/hydrogen system (a hybrid system based on battery and hydrogen (HS-BH for reliable and economic supply. Two objectives that take the minimum annual system cost and maximum system reliability described as the loss of power supply probability (LPSP have been addressed for sizing HS-BH from a more comprehensive perspective, considering the basic demand of load, the profit from hydrogen, which is produced by HS-BH, and an effective energy storage strategy. An improved ant colony optimization (ACO algorithm has been presented to solve the sizing problem of HS-BH. Finally, a simulation experiment has been done to demonstrate the developed results, in which some comparisons have been done to emphasize the advantage of HS-BH with the aid of data from an island of Zhejiang, China.

  14. Stand-Alone Containment Analysis of the Phébus FPT Tests with the ASTEC and the MELCOR Codes: The FPT-0 Test

    Directory of Open Access Journals (Sweden)

    Bruno Gonfiotti

    2017-01-01

    Full Text Available The integral Phébus tests were probably one of the most important experimental campaigns performed to investigate the progression of severe accidents in light water reactors. In these tests, the degradation of a PWR fuel bundle was investigated employing different control rod materials and burn-up levels in strongly or weakly oxidizing conditions. From the results of such tests, numerical codes such as ASTEC and MELCOR have been developed to describe the evolution of a severe accident. After the termination of the experimental Phébus campaign, these two codes were furthermore expanded. Therefore, the aim of the present work is to reanalyze the first Phébus test (FPT-0 employing the updated ASTEC and MELCOR versions to ensure that the new improvements introduced in such codes allow also a better prediction of these Phébus tests. The analysis focuses on the stand-alone containment aspects of this test, and the paper summarizes the main thermal-hydraulic results and presents different sensitivity analyses carried out on the aerosols and fission products behavior. This paper is part of a series of publications covering the four executed Phébus tests employing a solid PWR fuel bundle: FPT-0, FPT-1, FPT-2, and FPT-3.

  15. Development of Stand Alone Application Tool for Processing and Quality Measurement of Weld Imperfection Image Captured by μ-Focused Digital Radiography Using MATLAB- Based Graphical User Interface

    Directory of Open Access Journals (Sweden)

    PZ Nadila

    2012-12-01

    Full Text Available Digital radiography incresingly is being applied in the fabrication industry. Compared to film- based radiography, digitally radiographed images can be acquired with less time and fewer exposures. However, noises can simply occur on the digital image resulting in a low-quality result. Due to this and the system’s complexity, parameters’ sensitivity, and environmental effects, the results can be difficult to interpret, even for a radiographer. Therefore, the need of an application tool to improve and evaluate the image is becoming urgent. In this research, a user-friendly tool for image processing and image quality measurement was developed. The resulting tool contains important components needed by radiograph inspectors in analyzing defects and recording the results. This tool was written by using image processing and the graphical user interface development environment and compiler (GUIDE toolbox available in Matrix Laboratory (MATLAB R2008a. In image processing methods, contrast adjustment, and noise removal, edge detection was applied. In image quality measurement methods, mean square error (MSE, peak signal-to-noise ratio (PSNR, modulation transfer function (MTF, normalized signal-to-noise ratio (SNRnorm, sensitivity and unsharpness were used to measure the image quality. The graphical user interface (GUI wass then compiled to build a Windows, stand-alone application that enables this tool to be executed independently without the installation of MATLAB.

  16. Methodology for predicting sequences of mean monthly clearness index and daily solar radiation data in remote areas: Application for sizing a stand-alone PV system

    Energy Technology Data Exchange (ETDEWEB)

    Mellit, A. [Department of Electronics, Institute of Sciences Engineering, Centre University of Medea, Medea 26000 (Algeria); Department of Electronics, Faculty of Science Engineering, Blida University, Blida 09000 (Algeria); Kalogirou, S.A. [Higher Technical Institute, P.O. Box 20423, Nicosia 2152 (Cyprus); Shaari, S. [Faculty of Applied Sciences, Universiti Teknologi MARA 40450 Shah Alam, Selangor (Malaysia); Salhi, H. [Department of Electronics, Faculty of Science Engineering, Blida University, Blida 09000 (Algeria); Hadj Arab, A. [Development Centre of Renewable Energy (CDER), P.O. Box 62, Bouzareah, Algiers 16000 (Algeria); Departamento de Energias Renerables, CIEMAT, Arda Complutense, 22, Madrid 28040 (Spain)

    2008-07-15

    In this paper, a suitable adaptive neuro-fuzzy inference system (ANFIS) model is presented for estimating sequences of mean monthly clearness index (anti K{sub t}) and total solar radiation data in isolated sites based on geographical coordinates. The magnitude of solar radiation is the most important parameter for sizing photovoltaic (PV) systems. The ANFIS model is trained by using a multi-layer perceptron (MLP) based on fuzzy logic (FL) rules. The inputs of the ANFIS are the latitude, longitude, and altitude, while the outputs are the 12-values of mean monthly clearness index anti K{sub t}. These data have been collected from 60 locations in Algeria. The results show that the performance of the proposed approach in the prediction of mean monthly clearness index anti K{sub t} is favorably compared to the measured values. The root mean square error (RMSE) between measured and estimated values varies between 0.0215 and 0.0235 and the mean absolute percentage error (MAPE) is less than 2.2%. In addition, a comparison between the results obtained by the ANFIS model and artificial neural network (ANN) models, is presented in order to show the advantage of the proposed method. An example for sizing a stand-alone PV system is also presented. This technique has been applied to Algerian locations, but it can be generalized for any geographical position. It can also be used for estimating other meteorological parameters such as temperature, humidity and wind speed. (author)

  17. A Study on Electric Power Smoothing System for Lead-Acid Battery of Stand-Alone Natural Energy Power System Using EDLC

    Science.gov (United States)

    Jia, Yan; Shibata, Ryosuke; Yamamura, Naoki; Ishida, Muneaki

    To resolve energy shortage and global warming problem, renewable natural resource and its power system has been gradually generalizing. However, the power fluctuation suppressing in short period and the balance control of consumption and supply in long period are two of main problems that need to be resolved urgently in natural energy power system. In Stand-alone Natural Energy Power System (SNEPS) with power energy storage devices, power fluctuation in short period is one of the main reasons that recharge cycle times increase and lead-acid battery early failure. Hence, to prolong the service life of lead-acid battery and improve power quality through suppressing the power fluctuation, we proposed a method of electric power smoothing for lead-acid battery of SNEPS using bi-directional Buck/Boost converter and Electric Double Layer Capacitor (EDLC) in this paper. According to the test data of existing SNEPS, a power fluctuation condition is selected and as an example to analyze the validity of the proposed method. The analysis of frequency characteristics indicates the power fluctuation is suppressed a desired range in the target frequency region. The experimental results of confirmed the feasibility of the proposed system and the results well satisfy the requirement of system design.

  18. A case study of a typical 2.32 kW{sub P} stand-alone photovoltaic (SAPV) in composite climate of New Delhi (India)

    Energy Technology Data Exchange (ETDEWEB)

    Chel, Arvind; Tiwari, G.N. [Center for Energy Studies (CES), Indian Institute of Technology, Hauz Khas, New Delhi 110 016 (India)

    2011-04-15

    This paper presents rigorous experimental outdoor performance of a 2.32 kW{sub P} stand-alone photovoltaic (SAPV) system in New Delhi (India) for four weather types in each month such as clear, hazy, partially cloudy/foggy and fully cloudy/foggy weather conditions respectively. The daily power generated from the existing SAPV system was experimentally found in the range of 4-6 kW h/day depending on the prevailing sky conditions. The number of days and daily power generated corresponding to four weather types in each month were used to determine monthly and subsequently annual power generation from the existing SAPV system. There are three daily load profiles with and without earth to air heat exchanger suitable for three seasons like summer (3.75-6.15 kW h/day), winter (2.79-5.19 kW h/day) and rainy (3.75 kW h/day). The hourly efficiency of the SAPV system components are determined and presented in this paper. The life cycle cost (LCC) analysis for the existing typical SAPV system is carried out to determine unit cost of electricity. The effect of annual degradation rate of PV system efficiency is also presented in this paper. The energy production factor (EPF) and the energy payback time (EPBT) of the SAPV system was also determined and presented in this paper. (author)

  19. CRionScan: A stand-alone real time controller designed to perform ion beam imaging, dose controlled irradiation and proton beam writing

    Science.gov (United States)

    Daudin, L.; Barberet, Ph.; Serani, L.; Moretto, Ph.

    2013-07-01

    High resolution ion microbeams, usually used to perform elemental mapping, low dose targeted irradiation or ion beam lithography needs a very flexible beam control system. For this purpose, we have developed a dedicated system (called “CRionScan”), on the AIFIRA facility (Applications Interdisciplinaires des Faisceaux d'Ions en Région Aquitaine). It consists of a stand-alone real-time scanning and imaging instrument based on a Compact Reconfigurable Input/Output (Compact RIO) device from National Instruments™. It is based on a real-time controller, a Field Programmable Gate Array (FPGA), input/output modules and Ethernet connectivity. We have implemented a fast and deterministic beam scanning system interfaced with our commercial data acquisition system without any hardware development. CRionScan is built under LabVIEW™ and has been used on AIFIRA's nanobeam line since 2009 (Barberet et al., 2009, 2011) [1,2]. A Graphical User Interface (GUI) embedded in the Compact RIO as a web page is used to control the scanning parameters. In addition, a fast electrostatic beam blanking trigger has been included in the FPGA and high speed counters (15 MHz) have been implemented to perform dose controlled irradiation and on-line images on the GUI. Analog to Digital converters are used for the beam current measurement and in the near future for secondary electrons imaging. Other functionalities have been integrated in this controller like LED lighting using Pulse Width Modulation and a “NIM Wilkinson ADC” data acquisition.

  20. CRionScan: A stand-alone real time controller designed to perform ion beam imaging, dose controlled irradiation and proton beam writing

    Energy Technology Data Exchange (ETDEWEB)

    Daudin, L., E-mail: daudin@cenbg.in2p3.fr [Université Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Barberet, Ph.; Serani, L.; Moretto, Ph. [Université Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France)

    2013-07-01

    High resolution ion microbeams, usually used to perform elemental mapping, low dose targeted irradiation or ion beam lithography needs a very flexible beam control system. For this purpose, we have developed a dedicated system (called “CRionScan”), on the AIFIRA facility (Applications Interdisciplinaires des Faisceaux d’Ions en Région Aquitaine). It consists of a stand-alone real-time scanning and imaging instrument based on a Compact Reconfigurable Input/Output (Compact RIO) device from National Instruments™. It is based on a real-time controller, a Field Programmable Gate Array (FPGA), input/output modules and Ethernet connectivity. We have implemented a fast and deterministic beam scanning system interfaced with our commercial data acquisition system without any hardware development. CRionScan is built under LabVIEW™ and has been used on AIFIRA’s nanobeam line since 2009 (Barberet et al., 2009, 2011) [1,2]. A Graphical User Interface (GUI) embedded in the Compact RIO as a web page is used to control the scanning parameters. In addition, a fast electrostatic beam blanking trigger has been included in the FPGA and high speed counters (15 MHz) have been implemented to perform dose controlled irradiation and on-line images on the GUI. Analog to Digital converters are used for the beam current measurement and in the near future for secondary electrons imaging. Other functionalities have been integrated in this controller like LED lighting using Pulse Width Modulation and a “NIM Wilkinson ADC” data acquisition.

  1. Stand-alone photovoltaic (PV) integrated with earth to air heat exchanger (EAHE) for space heating/cooling of adobe house in New Delhi (India)

    International Nuclear Information System (INIS)

    Chel, Arvind; Tiwari, G.N.

    2010-01-01

    This paper deals with an experimental outdoor annual performance evaluation of 2.32 kW P photovoltaic (PV) power system located at solar energy park in New Delhi composite climatic conditions. This PV system operates the daily electrical load nearly 10 kW h/day which comprises of various applications such as electric air blower of an earth to air heat exchanger (EAHE) used for heating/cooling of adobe house, ceiling fan, fluorescent tube-light, computer, submersible water pump, etc. The outdoor efficiencies, power generated and lost in PV system components were determined using hourly experimental measured data for 1 year on typical clear day in each month. These realistic data are useful for design engineers for outdoor assessment of PV system components. The energy conservation, mitigation of CO 2 emission and carbon credit potential of the existing PV integrated EAHE system is presented in this paper. Also, the energy payback time (EPBT) and unit cost of electricity were determined for both stand-alone PV (SAPV) and building roof integrated PV (BIPV) systems.

  2. Direct Flux Control for Stand-Alone Operation Brushless Doubly Fed Induction Generators Using a Resonant-Based Sliding-Mode Control Approach

    Directory of Open Access Journals (Sweden)

    Kai Ji

    2018-04-01

    Full Text Available In this paper, a novel voltage control strategy for stand-alone operation brushless doubly fed induction generators for variable speed constant frequency wind energy conversion systems was presented and discussed. Based on the model of the power generation system, the proposed direct flux control strategy employs a nonlinear reduced-order generalized integrator-based resonant sliding-mode control approach to directly calculate and regulate the output value of converter which the control winding stator requires so as to eliminate its instantaneous errors, without involving any synchronous rotating coordinate transformations. The stability, robustness and convergence capability of the proposed control strategy were described and analyzed. Owing to the fact no additional current control inner loops are involved, the system configuration is therefore simplified and the dynamic performance enhanced. A constant converter switching frequency was achieved by using space vector pulse width modulation, which reduces the harmonics of the generator terminal voltage. In addition, the feasibility and validity of the proposed scheme is verified by experiments, and excellent steady and transient performance is achieved.

  3. Oligosaccharide nanomedicine of alginate sodium improves therapeutic results of posterior lumbar interbody fusion with cages for degenerative lumbar disease in osteoporosis patients by downregulating serum miR-155

    OpenAIRE

    Qu Y; Wang Z; Zhou H; Kang M; Dong R; Zhao J

    2017-01-01

    Yang Qu, Zhengming Wang, Haohan Zhou, Mingyang Kang, Rongpeng Dong, Jianwu Zhao Department of Orthopedics, The Second Hospital of Jilin University, Changchun, People’s Republic of China Abstract: Degenerative lumbar disease (DLD) is a significant issue for public health. Posterior lumbar intervertebral fusion with cages (PLIFC) has high-level fusion rate and realignment on DLD. However, there are some complications following the surgery. Alginate oligosaccharides (AOS) have antiox...

  4. Lumbar lordosis restoration following single-level instrumented fusion comparing 4 commonly used techniques.

    Science.gov (United States)

    Dimar, John R; Glassman, Steven D; Vemuri, Venu M; Esterberg, Justin L; Howard, Jennifer M; Carreon, Leah Y

    2011-11-09

    A major sequelae of lumbar fusion is acceleration of adjacent-level degeneration due to decreased lumbar lordosis. We evaluated the effectiveness of 4 common fusion techniques in restoring lordosis: instrumented posterolateral fusion, translumbar interbody fusion, anteroposterior fusion with posterior instrumentation, and anterior interbody fusion with lordotic threaded (LT) cages (Medtronic Sofamor Danek, Memphis, Tennessee). Radiographs were measured preoperatively, immediately postoperatively, and a minimum of 6 months postoperatively. Parameters measured included anterior and posterior disk space height, lumbar lordosis from L3 to S1, and surgical level lordosis.No significant difference in demographics existed among the 4 groups. All preoperative parameters were similar among the 4 groups. Lumbar lordosis at final follow-up showed no difference between the anteroposterior fusion with posterior instrumentation, translumbar interbody fusion, and LT cage groups, although the posterolateral fusion group showed a significant loss of lordosis (-10°) (Plordosis and showed maintenance of anterior and posterior disk space height postoperatively compared with the other groups. Instrumented posterolateral fusion produces a greater loss of lordosis compared with anteroposterior fusion with posterior instrumentation, translumbar interbody fusion, and LT cages. Maintenance of lordosis and anterior and posterior disk space height is significantly better with anterior interbody fusion with LT cages. Copyright 2011, SLACK Incorporated.

  5. The international phase 4 validation study of the EORTC QLQ-SWB32: A stand-alone measure of spiritual well-being for people receiving palliative care for cancer

    NARCIS (Netherlands)

    Vivat, B.; Young, T. E.; Winstanley, J.; Arraras, J. I.; Black, K.; Boyle, F.; Bredart, A.; Costantini, A.; Guo, J.; Irarrazaval, M. E.; Kobayashi, K.; Kruizinga, R.; Navarro, M.; Omidvari, S.; Rohde, G. E.; Serpentini, S.; Spry, N.; van Laarhoven, H. W. M.; Yang, G. M.

    2017-01-01

    The EORTC Quality of Life Group has just completed the final phase (field-testing and validation) of an international project to develop a stand-alone measure of spiritual well-being (SWB) for palliative cancer patients. Participants (n = 451)-from 14 countries on four continents; 54% female; 188

  6. The Impact of Course Delivery Systems on Student Achievement and Sense of Community: A Comparison of Learning Community versus Stand-Alone Classroom Settings in an Open-Enrollment Inner City Public Community College

    Science.gov (United States)

    Bandyopadhyay, Pamela

    2010-01-01

    This study examined the effects of two types of course delivery systems (learning community classroom environments versus stand-alone classroom environments) on the achievement of students who were simultaneously enrolled in remedial and college-level social science courses at an inner city open-enrollment public community college. This study was…

  7. CANGS DB: a stand-alone web-based database tool for processing, managing and analyzing 454 data in biodiversity studies

    Directory of Open Access Journals (Sweden)

    Schlötterer Christian

    2011-06-01

    Full Text Available Abstract Background Next generation sequencing (NGS is widely used in metagenomic and transcriptomic analyses in biodiversity. The ease of data generation provided by NGS platforms has allowed researchers to perform these analyses on their particular study systems. In particular the 454 platform has become the preferred choice for PCR amplicon based biodiversity surveys because it generates the longest sequence reads. Nevertheless, the handling and organization of massive amounts of sequencing data poses a major problem for the research community, particularly when multiple researchers are involved in data acquisition and analysis. An integrated and user-friendly tool, which performs quality control, read trimming, PCR primer removal, and data organization is desperately needed, therefore, to make data interpretation fast and manageable. Findings We developed CANGS DB (Cleaning and Analyzing Next Generation Sequences DataBase a flexible, stand alone and user-friendly integrated database tool. CANGS DB is specifically designed to organize and manage the massive amount of sequencing data arising from various NGS projects. CANGS DB also provides an intuitive user interface for sequence trimming and quality control, taxonomy analysis and rarefaction analysis. Our database tool can be easily adapted to handle multiple sequencing projects in parallel with different sample information, amplicon sizes, primer sequences, and quality thresholds, which makes this software especially useful for non-bioinformaticians. Furthermore, CANGS DB is especially suited for projects where multiple users need to access the data. CANGS DB is available at http://code.google.com/p/cangsdb/. Conclusion CANGS DB provides a simple and user-friendly solution to process, store and analyze 454 sequencing data. Being a local database that is accessible through a user-friendly interface, CANGS DB provides the perfect tool for collaborative amplicon based biodiversity surveys

  8. Hydrogen-based energy storage unit for stand alone PV systems; L'hydrogene electrolytique comme moyen de stockage d'electricite pour systemes photovoltaiques isoles

    Energy Technology Data Exchange (ETDEWEB)

    Labbe, J

    2006-12-15

    Stand alone systems supplied only by a photovoltaic generator need an energy storage unit to be fully self sufficient. Lead acid batteries are commonly used to store energy because of their low cost, despite several operational constraints. A hydrogen-based energy storage unit (HESU) could be another candidate, including an electrolyser, a fuel cell and a hydrogen tank. However many efforts still need to be carried out for this technology to reach an industrial stage. In particular, market outlets must be clearly identified. The study of small stationary applications (few kW) is performed by numerical simulations. A simulator is developed in the Matlab/Simulink environment. It is mainly composed of a photovoltaic field and a storage unit (lead acid batteries, HESU, or hybrid storage HESU/batteries). The system component sizing is achieved in order to ensure the complete system autonomy over a whole year of operation. The simulator is tested with 160 load profiles (1 kW as a yearly mean value) and three locations (Algeria, France and Norway). Two coefficients are set in order to quantify the correlation between the power consumption of the end user and the renewable resource availability at both daily and yearly scales. Among the tested cases, a limit value of the yearly correlation coefficient came out, enabling to recommend the use of the most adapted storage to a considered case. There are cases for which using HESU instead of lead acid batteries can increase the system efficiency, decrease the size of the photovoltaic field and improve the exploitation of the renewable resource. In addition, hybridization of HESU with batteries always leads to system enhancements regarding its sizing and performance, with an efficiency increase by 10 to 40 % depending on the considered location. The good agreement between the simulation data and field data gathered on real systems enabled the validation of the models used in this study. (author)

  9. Further development of LLNA:DAE method as stand-alone skin-sensitization testing method and applied for evaluation of relative skin-sensitizing potency between chemicals.

    Science.gov (United States)

    Yamashita, Kunihiko; Shinoda, Shinsuke; Hagiwara, Saori; Itagaki, Hiroshi

    2015-04-01

    To date, there has been no well-established local lymph node assay (LLNA) that includes an elicitation phase. Therefore, we developed a modified local lymph node assay with an elicitation phase (LLNA:DAE) to discriminate true skin sensitizers from chemicals that gave borderline positive results and previously reported this assay. To develop the LLNA:DAE method as a useful stand-alone testing method, we investigated the complete procedure for the LLNA:DAE method using hexyl cinnamic aldehyde (HCA), isoeugenol, and 2,4-dinitrochlorobenzene (DNCB) as test compounds. We defined the LLNA:DAE procedure as follows: in the dose-finding test, four concentrations of chemical applied to dorsum of the right ear on days 1, 2, and 3 and dorsum of both ears on day 10. Ear thickness and skin irritation score were measured on days 1, 3, 5, 10, and 12. Local lymph nodes were excised and weighed on day 12. The test dose for the primary LLNA:DAE study was selected as the dose that gave the highest left ear lymph node weight in the dose-finding study, or the lowest dose that produced a left ear lymph node of over 4 mg. This procedure was validated using nine different chemicals. Furthermore, qualitative relationship was observed between the degree of elicitation response in the left ear lymph node and the skin sensitizing potency of 32 chemicals tested in this study and the previous study. These results indicated that LLNA:DAE method was as first LLNA method that was able to evaluate the skin sensitizing potential and potency in elicitation response.

  10. Effects of a stand-alone web-based electronic screening and brief intervention targeting alcohol use in university students of legal drinking age: A randomized controlled trial.

    Science.gov (United States)

    Ganz, Thomas; Braun, Michael; Laging, Marion; Schermelleh-Engel, Karin; Michalak, Johannes; Heidenreich, Thomas

    2018-02-01

    Many intervention efforts targeting student drinking were developed to address US college students, which usually involves underage drinking. It remains unclear, if research evidence from these interventions is generalizable to university and college students of legal drinking age, e.g., in Europe. To evaluate the effectiveness of a translated and adapted version of the eCHECKUP TO GO, applied as stand-alone web-based electronic screening and brief intervention (e-SBI), in German university students at risk for hazardous drinking. A fully automated web-based two-arm parallel-group randomized controlled trial was conducted. Participants were randomized to an e-SBI or assessment-only (AO) condition. The current paper analyzed students with baseline AUDIT-C scores ≥3 for women and ≥4 for men (sample at baseline: e-SBI [n=514], AO [n=467]; 3-month follow-up: e-SBI [n=194], AO [n=231]; 6-month follow-up: e-SBI [n=146], AO [n=200]). The primary outcome was prior four weeks' alcohol consumption. Secondary outcomes were frequency of heavy drinking occasions, peak blood alcohol concentration, and number of alcohol-related problems. Mixed linear model analyses revealed significant interaction effects between groups and time points on the primary outcome after 3 and 6months. Compared to students in the AO condition, students in the e-SBI condition reported consuming 4.11 fewer standard drinks during the previous four weeks after 3months, and 4.78 fewer standard drinks after 6months. Mixed results were found on secondary outcomes. The results indicate that evidence on and knowledge of web-based e-SBIs based on US college student samples is transferable to German university students of legal drinking age. However, knowledge of what motivates students to complete programs under voluntary conditions, although rare, is needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Fusion

    CERN Document Server

    Mahaffey, James A

    2012-01-01

    As energy problems of the world grow, work toward fusion power continues at a greater pace than ever before. The topic of fusion is one that is often met with the most recognition and interest in the nuclear power arena. Written in clear and jargon-free prose, Fusion explores the big bang of creation to the blackout death of worn-out stars. A brief history of fusion research, beginning with the first tentative theories in the early 20th century, is also discussed, as well as the race for fusion power. This brand-new, full-color resource examines the various programs currently being funded or p

  12. Stand-alone containment analysis of Phébus FPT tests with ASTEC and MELCOR codes: the FPT-2 test.

    Science.gov (United States)

    Gonfiotti, Bruno; Paci, Sandro

    2018-03-01

    During the last 40 years, many studies have been carried out to investigate the different phenomena occurring during a Severe Accident (SA) in a Nuclear Power Plant (NPP). Such efforts have been supported by the execution of different experimental campaigns, and the integral Phébus FP tests were probably some of the most important experiments in this field. In these tests, the degradation of a Pressurized Water Reactor (PWR) fuel bundle was investigated employing different control rod materials and burn-up levels in strongly or weakly oxidizing conditions. From the findings on these and previous tests, numerical codes such as ASTEC and MELCOR have been developed to analyze the evolution of a SA in real NPPs. After the termination of the Phébus FP campaign, these two codes have been furthermore improved to implement the more recent findings coming from different experimental campaigns. Therefore, continuous verification and validation is still necessary to check that the new improvements introduced in such codes allow also a better prediction of these Phébus tests. The aim of the present work is to re-analyze the Phébus FPT-2 test employing the updated ASTEC and MELCOR code versions. The analysis focuses on the stand-alone containment aspects of this test, and three different spatial nodalizations of the containment vessel (CV) have been developed. The paper summarizes the main thermal-hydraulic results and presents different sensitivity analyses carried out on the aerosols and fission products (FP) behavior. When possible, a comparison among the results obtained during this work and by different authors in previous work is also performed. This paper is part of a series of publications covering the four Phébus FP tests using a PWR fuel bundle: FPT-0, FPT-1, FPT-2, and FPT-3, excluding the FPT-4 one, related to the study of the release of low-volatility FP and transuranic elements from a debris bed and a pool of melted fuel.

  13. Stand-alone containment analysis of Phébus FPT tests with ASTEC and MELCOR codes: the FPT-2 test

    Directory of Open Access Journals (Sweden)

    Bruno Gonfiotti

    2018-03-01

    Full Text Available During the last 40 years, many studies have been carried out to investigate the different phenomena occurring during a Severe Accident (SA in a Nuclear Power Plant (NPP. Such efforts have been supported by the execution of different experimental campaigns, and the integral Phébus FP tests were probably some of the most important experiments in this field. In these tests, the degradation of a Pressurized Water Reactor (PWR fuel bundle was investigated employing different control rod materials and burn-up levels in strongly or weakly oxidizing conditions. From the findings on these and previous tests, numerical codes such as ASTEC and MELCOR have been developed to analyze the evolution of a SA in real NPPs. After the termination of the Phébus FP campaign, these two codes have been furthermore improved to implement the more recent findings coming from different experimental campaigns. Therefore, continuous verification and validation is still necessary to check that the new improvements introduced in such codes allow also a better prediction of these Phébus tests. The aim of the present work is to re-analyze the Phébus FPT-2 test employing the updated ASTEC and MELCOR code versions. The analysis focuses on the stand-alone containment aspects of this test, and three different spatial nodalizations of the containment vessel (CV have been developed. The paper summarizes the main thermal-hydraulic results and presents different sensitivity analyses carried out on the aerosols and fission products (FP behavior. When possible, a comparison among the results obtained during this work and by different authors in previous work is also performed. This paper is part of a series of publications covering the four Phébus FP tests using a PWR fuel bundle: FPT-0, FPT-1, FPT-2, and FPT-3, excluding the FPT-4 one, related to the study of the release of low-volatility FP and transuranic elements from a debris bed and a pool of melted fuel. Keywords: Safety

  14. Oligosaccharide nanomedicine of alginate sodium improves therapeutic results of posterior lumbar interbody fusion with cages for degenerative lumbar disease in osteoporosis patients by downregulating serum miR-155

    Directory of Open Access Journals (Sweden)

    Qu Y

    2017-11-01

    Full Text Available Yang Qu, Zhengming Wang, Haohan Zhou, Mingyang Kang, Rongpeng Dong, Jianwu Zhao Department of Orthopedics, The Second Hospital of Jilin University, Changchun, People’s Republic of China Abstract: Degenerative lumbar disease (DLD is a significant issue for public health. Posterior lumbar intervertebral fusion with cages (PLIFC has high-level fusion rate and realignment on DLD. However, there are some complications following the surgery. Alginate oligosaccharides (AOS have antioxidant and anti-inflammatory activities and may be suitable for infection therapy. MiR-155 is a biomarker associated with inflammatory and oxidative stress. AOS may promote PLIFC therapy by regulating miR-155. Pluronic nanoparticles and oligosaccharide nanomedicine of alginate sodium (ONAS were prepared with ampicillin at size <200 nm. Ninety-six DLD osteoporosis patients received PLIFC and were evenly assigned into ONAS group (OG, oral administration of 100 mg ONAS daily and control group (PG, 100 mg pluronic nanoparticles. Serum miR-155 level was measured by real-time quantitative PCR. The levels of superoxide dismutase (SOD, glutathione (GSH, aspartate aminotransaminase (AST, alanine aminotransferase (ALT, interleukin-1β (IL-1β, and interleukin-1 receptor antagonist (IL-1ra were measured. Weighted mean difference (WMD, relative risk (RR, complications, surgery infection rate, fusion rate, and Japanese Orthopaedic Association (JOA scores were used to evaluate therapeutic efficacy. After 1-month therapy, infection rates and side effects were lower in OG than those in PG (RR =0.64, 95% confidence interval [CI] [0.48, 0.84], P=0.001. The fusion rates were higher in OG than in PG (WMD =21.96, 95% CI [–0.24, 37.62], P=0.021. The JOA scores were higher in OG than in PG (RR =0.52, 95% CI [0.33, 0.84], P=0.007, and no significant difference was found for the visual analog scale and Oswestry Disability Index. Serum levels of miR-155, ALT, AST, and IL-1β were lower while

  15. Oligosaccharide nanomedicine of alginate sodium improves therapeutic results of posterior lumbar interbody fusion with cages for degenerative lumbar disease in osteoporosis patients by downregulating serum miR-155.

    Science.gov (United States)

    Qu, Yang; Wang, Zhengming; Zhou, Haohan; Kang, Mingyang; Dong, Rongpeng; Zhao, Jianwu

    2017-01-01

    Degenerative lumbar disease (DLD) is a significant issue for public health. Posterior lumbar intervertebral fusion with cages (PLIFC) has high-level fusion rate and realignment on DLD. However, there are some complications following the surgery. Alginate oligosaccharides (AOS) have antioxidant and anti-inflammatory activities and may be suitable for infection therapy. MiR-155 is a biomarker associated with inflammatory and oxidative stress. AOS may promote PLIFC therapy by regulating miR-155. Pluronic nanoparticles and oligosaccharide nanomedicine of alginate sodium (ONAS) were prepared with ampicillin at size effects were lower in OG than those in PG (RR =0.64, 95% confidence interval [CI] [0.48, 0.84], P =0.001). The fusion rates were higher in OG than in PG (WMD =21.96, 95% CI [-0.24, 37.62], P =0.021). The JOA scores were higher in OG than in PG (RR =0.52, 95% CI [0.33, 0.84], P =0.007), and no significant difference was found for the visual analog scale and Oswestry Disability Index. Serum levels of miR-155, ALT, AST, and IL-1β were lower while SOD, GSH, and IL-1ra were higher in OG than in PG. MiR-155 mimic increased the levels of ALT, AST, and IL-1β and reduced the levels of SOD, GSH, and IL-1ra. In contrast, miR-155 inhibitor had reverse results. Therefore, ONAS has better improvement in complications and therapeutic effects on DLD by regulating serum miR-155.

  16. Wireless network of stand-alone end effect probes for soil in situ permittivity measurements over the 100MHZ-6GHz frequency range

    Science.gov (United States)

    Demontoux, François; Bircher, Simone; Ruffié, Gilles; Bonnaudiin, Fabrice; Wigneron, Jean-Pierre; Kerr, Yann

    2017-04-01

    , it should be useful to install many probes on the same site to obtain permittivity measurements over a large area. To reach this goal, the probes should communicate with each other to send data to a record device. Furthermore, it is needed to record measurements over a long time period (many months) to study the in-situ dielectric soil property variations according to changing weather conditions and seasonal trends. The goal of the research work presented is to develop a dielectric sensor system based on end effect probes able to communicate the data using wireless technology. It must be stand-alone from an electric and data recording point of view so it must integrate a VNA circuit instead of the ANRITSU VNA used for the moment. The LoRa wireless technology has been selected because of its low electric consumption and the large distance between equipment available. LoRaWAN™ is a Low Power Wide Area Network specification intended for wireless battery operated devices. The LoRaWAN data rates range from 0.3 kbps to 50 kbps which is sufficient for our probes' data exchanges. We will present the work done to perform the VNA and the LoRa communication board as well as the work done to improve the probes and the permittivity computation algorithm.

  17. Transforaminal lumbar interbody graft placement using an articulating delivery arm facilitates increased segmental lordosis with superior anterior and midline graft placement.

    Science.gov (United States)

    Shau, David N; Parker, Scott L; Mendenhall, Stephen K; Zuckerman, Scott L; Godil, Saniya S; Devin, Clinton J; McGirt, Matthew J

    2015-05-01

    Transforaminal lumbar interbody fusion (TLIF) is a frequently performed method of lumbar arthrodesis in patients failing medical management of back and leg pain. Accurate placement of the interbody graft and restoration of lordosis has been shown to be crucial when performing lumbar fusion procedures. We performed a single-surgeon, prospective, randomized study to determine whether a novel articulating versus traditional straight graft delivery arm system allows for superior graft placement and increased lordosis for single-level TLIF. Thirty consecutive patients undergoing single-level TLIF were included and prospectively randomized to one of the 2 groups (articulated vs. straight delivery arm system). Three radiographic characteristics were evaluated at 6-week follow-up: (1) degree of segmental lumbar lordosis at the fused level; (2) the percent anterior location of the interbody graft in disk space; and (3) the distance (mm) off midline of the interbody graft placement. Randomization yielded 16 patients in the articulated delivery arm cohort and 14 in the straight delivery arm cohort. The articulating delivery arm system yielded an average of 14.7-degree segmental lordosis at fused level, 35% anterior location, and 3.6 mm off midline. The straight delivery arm system yielded an average of 10.7-degree segmental lordosis at fused level, 46% anterior location, and 7.0 mm off midline. All 3 comparisons were statistically significant (Plordosis compared with a traditional straight delivery arm system.

  18. Tricortical cervical inter-body screw fixation.

    Directory of Open Access Journals (Sweden)

    Goel A

    1997-01-01

    Full Text Available A new tricortical method of screw implantation for anterior cervical interbody plate fixation is described. The screws are placed obliquely such that they engage the anterior cortex of the body and traverse through the cortices adjoining the disc space. By this method the screws not only hold the plate firmly with a tricortical purchase, but by virtue of their course stabilize the two adjoining vertebral bodies by themselves. Sixteen patients were treated by this method. In three of these cases only tricortical screws without the metal plate were used for fixation. The advantages of the technique are discussed.

  19. IEA PVPS Task 3. Use of photovoltaic systems in stand-alone and island applications. 'Swiss participation'; IEA PVPS Task 3. Use of photovoltaic systems in stand-alone and island applications. 'Participation Suisse'

    Energy Technology Data Exchange (ETDEWEB)

    Villoz, M. [Dynatex SA, Morges (Switzerland)

    2004-07-01

    This report describes the work done during five years of the second phase of Task 3 of the photovoltaic power systems programme of the International Energy Agency (IEA-PVPS). Task 3 activities were concentrated on stand-alone photovoltaic systems with the main effort on improving the quality and reducing the cost of these systems. The work was divided in 2 sub-tasks whose first one was concentrated on quality insurance schemes and second one on technical recommendations coming from practical experience. Twelve original reports have been published covering topics that can be sorted in 4 categories: the first one is dedicated on quality issues with a review of existing standards in the participating countries and a double paper giving quality assurance recommendations on project management and examples of applying these rules in practical cases. The second category dwelled on photovoltaic systems with papers on charge controllers, on lightning protection and monitoring of systems. The third category presents interesting studies on the storage of energy which remains the main subject where improvements should be made in order to lower the cost of energy; four papers describe the management and the test procedures of lead-acid batteries, how to choose a lead-acid battery and finally are there alternatives to lead-acid batteries for the storage of photovoltaic electricity. The last category worked on loads and users of renewable energy and gives a large amount of experience with loads, how to choose them and how the energy can be better used through demand side management. (author)

  20. Tissue identification with micro-magnetic resonance imaging in a caprine spinal fusion model

    NARCIS (Netherlands)

    Uffen, M.; Krijnen, M.; Hoogendoorn, R.; Strijkers, G.; Everts, V.; Wuisman, P.; Smit, T.

    2008-01-01

    Nonunion is a major complication of spinal interbody fusion. Currently X-ray and computed tomography (CT) are used for evaluating the spinal fusion process. However, both imaging modalities have limitations in judgment of the early stages of this fusion process, as they only visualize mineralized

  1. Search Improvement Process-Chaotic Optimization-Particle Swarm Optimization-Elite Retention Strategy and Improved Combined Cooling-Heating-Power Strategy Based Two-Time Scale Multi-Objective Optimization Model for Stand-Alone Microgrid Operation

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2017-11-01

    Full Text Available The optimal dispatching model for a stand-alone microgrid (MG is of great importance to its operation reliability and economy. This paper aims at addressing the difficulties in improving the operational economy and maintaining the power balance under uncertain load demand and renewable generation, which could be even worse in such abnormal conditions as storms or abnormally low or high temperatures. A new two-time scale multi-objective optimization model, including day-ahead cursory scheduling and real-time scheduling for finer adjustments, is proposed to optimize the operational cost, load shedding compensation and environmental benefit of stand-alone MG through controllable load (CL and multi-distributed generations (DGs. The main novelty of the proposed model is that the synergetic response of CL and energy storage system (ESS in real-time scheduling offset the operation uncertainty quickly. And the improved dispatch strategy for combined cooling-heating-power (CCHP enhanced the system economy while the comfort is guaranteed. An improved algorithm, Search Improvement Process-Chaotic Optimization-Particle Swarm Optimization-Elite Retention Strategy (SIP-CO-PSO-ERS algorithm with strong searching capability and fast convergence speed, was presented to deal with the problem brought by the increased errors between actual renewable generation and load and prior predictions. Four typical scenarios are designed according to the combinations of day types (work day or weekend and weather categories (sunny or rainy to verify the performance of the presented dispatch strategy. The simulation results show that the proposed two-time scale model and SIP-CO-PSO-ERS algorithm exhibit better performance in adaptability, convergence speed and search ability than conventional methods for the stand-alone MG’s operation.

  2. The international phase 4 validation study of the EORTC QLQ-SWB32: a stand-alone measure of spiritual wellbeing (SWB) for people receiving palliative care for cancer

    OpenAIRE

    Vivat, B.; Young, T.; Winstanley, J.; Arraras, J.; Black, K.; Boyle, F.; Brédart, A.; Costantini, A.; Guo, J.; Irarrazaval, M. E.; Kobayashi, K.; Kruizinga, R.; Navarro, M.; Omidvari, S.; Rohde, G. E.

    2017-01-01

    The EORTC Quality of Life (QL) Group has just completed the final phase (field-testing and validation) of an international project to develop a stand-alone measure of spiritual wellbeing (SWB) for palliative cancer patients. Participants (n= 451) - from 14 countries on four continents; 54% female; 188 Christian, 50 Muslim, 156 with no religion - completed a provisional 36-item measure of SWB plus the EORTC QLQ-C15-PAL (PAL), then took part in a structured debriefing interview. All items showe...

  3. Feasibility Analysis and Simulation of a Stand-Alone Photovoltaic Energy System for Electricity Generation and Environmental Sustainability – Equivalent to 650VA Fuel-Powered Generator – Popularly Known as “I Pass My Neighbour”

    International Nuclear Information System (INIS)

    Ani, Vincent Anayochukwu

    2015-01-01

    Photovoltaic (PV) power system can be used to replace wholly 650VA generator for electricity generation for household use in Nigeria. This paper presented the feasibility analysis of load data and simulation study of a stand-alone PV power system that produced the electrical needs of a household. This study is based on designing of PV energy system for household use. The patterns of load consumption within the household were studied and suitably modeled for simulation. The simulation study indicates that energy requirements to provide electricity, which is equivalent to 650VA generator for household use in Nigeria, can be accomplished by 520 W solar PV array, 2312 Ah nominal capacity battery, and a 1 kW DC/AC inverter. This would be suitable for deployment of 100% clean energy for environmental sustainability and uninterruptable power performance in the household. The results of this research show that, with a low-power consuming appliances, it is possible to meet the entire annual electricity demand of a single household solely through a stand-alone PV energy supply. Installing solar panels by most Nigerian home can significantly reduce home reliance on government power thereby reduce the strain on the current capacity of our power generation infrastructure. A detailed design and description of the system were presented in this paper.

  4. Feasibility Analysis and Simulation of a Stand-Alone Photovoltaic Energy System for Electricity Generation and Environmental Sustainability – Equivalent to 650VA Fuel-Powered Generator – Popularly Known as “I Pass My Neighbour”

    Energy Technology Data Exchange (ETDEWEB)

    Ani, Vincent Anayochukwu, E-mail: vincent_ani@yahoo.com [Department of Electronic Engineering, University of Nigeria Nsukka, Nsukka (Nigeria)

    2015-09-11

    Photovoltaic (PV) power system can be used to replace wholly 650VA generator for electricity generation for household use in Nigeria. This paper presented the feasibility analysis of load data and simulation study of a stand-alone PV power system that produced the electrical needs of a household. This study is based on designing of PV energy system for household use. The patterns of load consumption within the household were studied and suitably modeled for simulation. The simulation study indicates that energy requirements to provide electricity, which is equivalent to 650VA generator for household use in Nigeria, can be accomplished by 520 W solar PV array, 2312 Ah nominal capacity battery, and a 1 kW DC/AC inverter. This would be suitable for deployment of 100% clean energy for environmental sustainability and uninterruptable power performance in the household. The results of this research show that, with a low-power consuming appliances, it is possible to meet the entire annual electricity demand of a single household solely through a stand-alone PV energy supply. Installing solar panels by most Nigerian home can significantly reduce home reliance on government power thereby reduce the strain on the current capacity of our power generation infrastructure. A detailed design and description of the system were presented in this paper.

  5. Multiexpandable cage for minimally invasive posterior lumbar interbody fusion

    OpenAIRE

    Miller, Larry E.; Coe,Jeffrey; Zucherman,James; Kucharzyk,Donald; Poelstra,Kornelis; Kunwar,Sandeep

    2016-01-01

    Jeffrey D Coe,1 James F Zucherman,2 Donald W Kucharzyk,3 Kornelis A Poelstra,4 Larry E Miller,5 Sandeep Kunwar,6 1Silicon Valley Spine Institute, Campbell, 2San Francisco Orthopaedic Surgeons, San Francisco, CA, 3Orthopaedic Pediatric and Spine, Crown Point, IN, 4Department of Surgery, Sacred Heart Hospital on the Emerald Coast, Miramar Beach, FL, 5Miller Scientific Consulting, Inc., Asheville, NC, 6Bell Neuroscience Institute, Washington Hospital Healthcare System, Fremont, CA, USA Abstract:...

  6. Lateral Transpsoas Fusion: Indications and Outcomes

    Directory of Open Access Journals (Sweden)

    Vishal C. Patel

    2012-01-01

    Full Text Available Spinal fusion historically has been used extensively, and, recently, the lateral transpsoas approach to the thoracic and lumbar spine has become an increasingly common method to achieve fusion. Recent literature on this approach has elucidated its advantage over more traditional anterior and posterior approaches, which include a smaller tissue dissection, potentially lower blood loss, no need for an access surgeon, and a shorter hospital stay. Indications for the procedure have now expanded to include degenerative disc disease, spinal stenosis, degenerative scoliosis, nonunion, trauma, infection, and low-grade spondylolisthesis. Lateral interbody fusion has a similar if not lower rate of complications compared to traditional anterior and posterior approaches to interbody fusion. However, lateral interbody fusion has unique complications that include transient neurologic symptoms, motor deficits, and neural injuries that range from 1 to 60% in the literature. Additional studies are required to further evaluate and monitor the short- and long-term safety, efficacy, outcomes, and complications of lateral transpsoas procedures.

  7. Biomechanical Analysis of an Expandable Lumbar Interbody Spacer.

    Science.gov (United States)

    Soriano-Baron, Hector; Newcomb, Anna G U S; Malhotra, Devika; Palma, Atilio E; Martinez-Del-Campo, Eduardo; Crawford, Neil R; Theodore, Nicholas; Kelly, Brian P; Kaibara, Taro

    2018-06-01

    Recently developed expandable interbody spacers are widely accepted in spinal surgery; however, the resulting biomechanical effects of their use have not yet been fully studied. We analyzed the biomechanical effects of an expandable polyetheretherketone interbody spacer inserted through a bilateral posterior approach with and without different modalities of posterior augmentation. Biomechanical nondestructive flexibility testing was performed in 7 human cadaveric lumbar (L2-L5) specimens followed by axial compressive loading. Each specimen was tested under 6 conditions: 1) intact, 2) bilateral L3-L4 cortical screw/rod (CSR) alone, 3) WaveD alone, 4) WaveD + CSR, 5) WaveD + bilateral L3-L4 pedicle screw/rod (PSR), and 6) WaveD + CSR/PSR, where CSR/PSR was a hybrid construct comprising bilateral cortical-level L3 and pedicle-level L4 screws interconnected by rods. The range of motion (ROM) with the interbody spacer alone decreased significantly compared with the intact condition during flexion-extension (P = 0.02) but not during lateral bending or axial rotation (P ≥ 0.19). The addition of CSR or PSR to the interbody spacer alone condition significantly decreased the ROM compared with the interbody spacer alone (P ≤ 0.002); and WaveD + CSR, WaveD + PSR, and WaveD + CSR/PSR (hybrid) (P ≥ 0.29) did not differ. The axial compressive stiffness (resistance to change in foraminal height during compressive loading) with the interbody spacer alone did not differ from the intact condition (P = 0.96), whereas WaveD + posterior instrumentation significantly increased compressive stiffness compared with the intact condition and the interbody spacer alone (P ≤ 0.001). The WaveD alone significantly reduced ROM during flexion-extension while maintaining the axial compressive stiffness. CSR, PSR, and CSR/PSR hybrid constructs were all effective in augmenting the expandable interbody spacer system and improving its stability. Copyright © 2018 Elsevier Inc. All

  8. Fusão intersomática lombar transforaminal: experiência de uma instituição Fusión intersomática lumbar transforaminal: la experiencia de una institución Transforaminal lumbar interbody fusion: a single-center experience

    Directory of Open Access Journals (Sweden)

    Vinicius de Meldau Benites

    2012-12-01

    del dolor y/o claudicación neurogénicas en comparación con el status preoperatorio. Solamente cinco pacientes continuaron usando alguna medicación analgésica. Cinco pacientes presentaran alguna complicación, pero sólo dos de ellas están relacionadas directamente al procedimiento. CONCLUSIONES: Es una técnica segura, posible de ser realizada en todos los niveles de la columna lumbar y es aplicable a la mayoría de las enfermedades que afectan a esta región de la columna.OBJECTIVE: Describe the early results and experience from a reference center in spine surgery in São Paulo, Brazil with transforaminal lumbar interbody fusion (TLIF technique in its various indications. METHODS: We retrospectively reviewed the medical records of 25 patients who underwent surgery with TLIF technique in 2011. One patient was excluded because we considered that TLIF was not the most important technique used. The indications were 9 lumbar disc herniations, 7 spondylolistheses, 4 revision surgeries of which 2 were for pseudoarthroses and 2 for low back pain, and finally, 4 lumbar spinal stenoses. RESULTS: All the patients reported low back pain and/or neurologic claudication improvement when comparing to preoperative status. Only five patients continued using analgesics. Five patients presented some complication, but only two of them were related to the procedure. CONCLUSIONS: TLIF is a safe technique which can be performed at any lumbar level of the lumbar spine and is applicable to the majority of diseases that affect this region.

  9. Stand alone biofuel production from algae

    NARCIS (Netherlands)

    Wijffels, R.H.; Janssen, M.G.J.; Barbosa, M.J.

    2011-01-01

    In this feature, leading researchers in the field of microbial biotechnology speculate on the technical and conceptual developments that will drive innovative research and open new vistas over the next few years

  10. Informing Approaches in Establishing Stand Alone Community ...

    African Journals Online (AJOL)

    Literacy is usually considered the ability to read at a basic level. Now it is beginning to be defined more broadly to include applying reading, writing, and mathematical skills to obtain and use information and solve problems at levels of proficiency necessary to function in society, to achieve one's goals and develop one's ...

  11. Stand Alone Battery Thermal Management System

    Energy Technology Data Exchange (ETDEWEB)

    Brodie, Brad [Denso International America, Incorporated, Southfield, MI (United States)

    2015-09-30

    The objective of this project is research, development and demonstration of innovative thermal management concepts that reduce the cell or battery weight, complexity (component count) and/or cost by at least 20%. The project addresses two issues that are common problems with current state of the art lithium ion battery packs used in vehicles; low power at cold temperatures and reduced battery life when exposed to high temperatures. Typically, battery packs are “oversized” to satisfy the two issues mentioned above. The first phase of the project was spent making a battery pack simulation model using AMEsim software. The battery pack used as a benchmark was from the Fiat 500EV. FCA and NREL provided vehicle data and cell data that allowed an accurate model to be created that matched the electrical and thermal characteristics of the actual battery pack. The second phase involved using the battery model from the first phase and evaluate different thermal management concepts. In the end, a gas injection heat pump system was chosen as the dedicated thermal system to both heat and cool the battery pack. Based on the simulation model. The heat pump system could use 50% less energy to heat the battery pack in -20°C ambient conditions, and by keeping the battery cooler at hot climates, the battery pack size could be reduced by 5% and still meet the warranty requirements. During the final phase, the actual battery pack and heat pump system were installed in a test bench at DENSO to validate the simulation results. Also during this phase, the system was moved to NREL where testing was also done to validate the results. In conclusion, the heat pump system can improve “fuel economy” (for electric vehicle) by 12% average in cold climates. Also, the battery pack size, or capacity, could be reduced 5%, or if pack size is kept constant, the pack life could be increased by two years. Finally, the total battery pack and thermal system cost could be reduced 5% only if the system is integrated with the vehicle cabin air conditioning system. The reason why we were not able to achieve the 20% reduction target is because of the natural decay of the battery cell due to the number of cycles. Perhaps newer battery chemistries that are not so sensitive to cycling would have more potential for reducing the battery size due to thermal issues.

  12. Chapter 2: Stand-alone Applications - TOPCAT

    Science.gov (United States)

    Miller, C. J.

    Tool for OPerations on Catalogues And Tables or TOPCAT is a graphical viewer for table data. It offers a variety of ways to work with data tables, including a browser for the cell data, viewers for information about table and column metadata, dataset visualization, and even analysis. We discuss a small subset of TOPCAT's functionalities in this chapter. TOPCAT was originally developed as part of the Starlink program in the United Kingdom. It is now maintained by AstroGrid. The program is written in pure Java and available under the GNU General Public License. It is available for download and a version is included in the software distribution accompanying this book. TOPCAT is a GUI interface on top of the STIL library. A command line interface to this library, STILTS, described in Chapter 21 provides scriptable access to many of the capabilities described here. The purpose of this tutorial is to provide an overview of TOPCAT to the novice user. The best place to look for and learn about TOPCAT is the web page maintained by Mark B. Taylor. There, TOPCAT documentation is provided in HTML, PDF, via screen shots, etc. In this chapter we take the user through a few examples that give the general idea of how TOPCAT works. The majority of the functionality of TOPCAT is not included in this short tutorial. Our goal in this tutorial is to lead the reader through an exercise that would result in a publication quality figure (e.g. for a journal article). Specifically, we will use TOPCAT to show how the color-magnitude relation of a galaxy cluster compares to that of all galaxies in the Sloan Digital Sky Survey (York et al. 2000). This diagnostic is used not only in cluster finding, but its linear fit can provide insight into the age and/or metallicity of the oldest galaxies in galaxy clusters (which are some of the oldest galaxies in the Universe). The data we need for this exercise are: 1) the entire spectroscopic galaxy catalog from the SDSS, with galaxy positions, galaxy redshifts, and galaxy magnitudes and 2) galaxy members of a known galaxy cluster. For the former, we will download data directly from the SDSS servers to our local machine for analysis. For the latter, we will use TOPCAT's ability to call live cone search services.

  13. Multi-site evaluation of a computer aided detection (CAD) algorithm for small acute intra-cranial hemorrhage and development of a stand-alone CAD system ready for deployment in a clinical environment

    Science.gov (United States)

    Deshpande, Ruchi R.; Fernandez, James; Lee, Joon K.; Chan, Tao; Liu, Brent J.; Huang, H. K.

    2010-03-01

    Timely detection of Acute Intra-cranial Hemorrhage (AIH) in an emergency environment is essential for the triage of patients suffering from Traumatic Brain Injury. Moreover, the small size of lesions and lack of experience on the reader's part could lead to difficulties in the detection of AIH. A CT based CAD algorithm for the detection of AIH has been developed in order to improve upon the current standard of identification and treatment of AIH. A retrospective analysis of the algorithm has already been carried out with 135 AIH CT studies with 135 matched normal head CT studies from the Los Angeles County General Hospital/ University of Southern California Hospital System (LAC/USC). In the next step, AIH studies have been collected from Walter Reed Army Medical Center, and are currently being processed using the AIH CAD system as part of implementing a multi-site assessment and evaluation of the performance of the algorithm. The sensitivity and specificity numbers from the Walter Reed study will be compared with the numbers from the LAC/USC study to determine if there are differences in the presentation and detection due to the difference in the nature of trauma between the two sites. Simultaneously, a stand-alone system with a user friendly GUI has been developed to facilitate implementation in a clinical setting.

  14. The international phase 4 validation study of the EORTC QLQ-SWB32: A stand-alone measure of spiritual well-being for people receiving palliative care for cancer.

    Science.gov (United States)

    Vivat, B; Young, T E; Winstanley, J; Arraras, J I; Black, K; Boyle, F; Bredart, A; Costantini, A; Guo, J; Irarrazaval, M E; Kobayashi, K; Kruizinga, R; Navarro, M; Omidvari, S; Rohde, G E; Serpentini, S; Spry, N; Van Laarhoven, H W M; Yang, G M

    2017-11-01

    The EORTC Quality of Life Group has just completed the final phase (field-testing and validation) of an international project to develop a stand-alone measure of spiritual well-being (SWB) for palliative cancer patients. Participants (n = 451)-from 14 countries on four continents; 54% female; 188 Christian; 50 Muslim; 156 with no religion-completed a provisional 36-item measure of SWB plus the EORTC QLQ-C15-PAL (PAL), then took part in a structured debriefing interview. All items showed good score distribution across response categories. We assessed scale structure using principal component analysis and Rasch analysis, and explored construct validity, and convergent/divergent validity with the PAL. Twenty-two items in four scoring scales (Relationship with Self, Relationships with Others, Relationship with Someone or Something Greater, and Existential) explained 53% of the variance. The measure also includes a global SWB item and nine other items. Scores on the PAL global quality-of-life item and Emotional Functioning scale weakly-moderately correlated with scores on the global SWB item and two of the four SWB scales. This new validated 32-item SWB measure addresses a distinct aspect of quality-of-life, and is now available for use in research and clinical practice, with a role as both a measurement and an intervention tool. © 2017 John Wiley & Sons Ltd.

  15. Fusion Power Demonstration III

    International Nuclear Information System (INIS)

    Lee, J.D.

    1985-07-01

    This is the third in the series of reports covering the Fusion Power Demonstration (FPD) design study. This volume considers the FPD-III configuration that incorporates an octopole end plug. As compared with the quadrupole end-plugged designs of FPD-I and FPD-II, this octopole configuration reduces the number of end cell magnets and shortens the minimum ignition length of the central cell. The end-cell plasma length is also reduced, which in turn reduces the size and cost of the end cell magnets and shielding. As a contiuation in the series of documents covering the FPD, this report does not stand alone as a design description of FPD-III. Design details of FPD-III subsystems that do not differ significantly from those of the FPD-II configuration are not duplicated in this report

  16. Outcome of instrumented spinal fusion for chronic low back pain: review of 100 patients

    International Nuclear Information System (INIS)

    Qureshi, M.A; Pasha, I.F.; Malik, A.S.; Asad, A.; Aebi, M.

    2010-01-01

    Objective of this study was to evaluate the outcome of instrumented spinal fusion in selected patients with Chronic Low Back Pain (CLBP) in our setup. Consecutive first one hundred patients were selected from spine unit database that underwent instrumented spinal fusion for chronic low back pain lasting more than one year, due to degenerative disease of spine. Average age was 42 years. There were 62 males and 38 females. Diagnosis included; spinal stenosis (26%), failed disc surgery (22%), spondylolisthesis (19%), degenerative disc disease (17%), and instability (16%). Operations performed; Pedicle Screw Fixation (PSF) with Postero-lateral Fusion (PLF) in 3% patients. Trans Laminar Facet Screw (TLFS) with PLF in 24% patients. Anterior Lumbar Inter-body Fusion (ALIF) in 9% patients. Posterior Lumbar Inter-body Fusion (PLIF) in 40% patients and Trans-foraminal Lumbar Inter-body Fusion (TLIF) in 24% patients. Average follow up was for 30 months. 86% patients had full spinal fusion. 71% patients were fully satisfied with treatment, 28% were partially satisfied. Post-operatively, on average, visual analogue scale (VAS) showed 48 points significant improvement and Oswestry Disability Index (ODI) showed 53 points significant improvement. Instrumented Spinal Fusion is effective in our set up for relieving symptoms and improving functional outcome in selected patients with debilitating Chronic Low Back Pain due to degenerative disease of spine. Single fusion technique is not ideal for all types of patients and surgeon has to be versatile and trained in using different fusion techniques as the situation demands. (author)

  17. A Narrative Review of Lumbar Fusion Surgery With Relevance to Chiropractic Practice.

    Science.gov (United States)

    Daniels, Clinton J; Wakefield, Pamela J; Bub, Glenn A; Toombs, James D

    2016-12-01

    The purpose of this narrative review was to describe the most common spinal fusion surgical procedures, address the clinical indications for lumbar fusion in degeneration cases, identify potential complications, and discuss their relevance to chiropractic management of patients after surgical fusion. The PubMed database was searched from the beginning of the record through March 31, 2015, for English language articles related to lumbar fusion or arthrodesis or both and their incidence, procedures, complications, and postoperative chiropractic cases. Articles were retrieved and evaluated for relevance. The bibliographies of selected articles were also reviewed. The most typical lumbar fusion procedures are posterior lumbar interbody fusion, anterior lumbar interbody fusion, transforaminal interbody fusion, and lateral lumbar interbody fusion. Fair level evidence supports lumbar fusion procedures for degenerative spondylolisthesis with instability and for intractable low back pain that has failed conservative care. Complications and development of chronic pain after surgery is common, and these patients frequently present to chiropractic physicians. Several reports describe the potential benefit of chiropractic management with spinal manipulation, flexion-distraction manipulation, and manipulation under anesthesia for postfusion low back pain. There are no published experimental studies related specifically to chiropractic care of postfusion low back pain. This article describes the indications for fusion, common surgical practice, potential complications, and relevant published chiropractic literature. This review includes 10 cases that showed positive benefits from chiropractic manipulation, flexion-distraction, and/or manipulation under anesthesia for postfusion lumbar pain. Chiropractic care may have a role in helping patients in pain who have undergone lumbar fusion surgery.

  18. Post-processing in cardiovascular computed tomography. Performance of a client server solution versus a stand-alone solution; Bildnachverarbeitung in der kardiovaskulaeren Computertomografie. Performance von Client-Server- versus Einzelplatzloesung

    Energy Technology Data Exchange (ETDEWEB)

    Luecke, C.; Foldyna, B.; Andres, C.; Grothoff, M.; Nitzsche, S.; Gutberlet, M.; Lehmkuhl, L. [Leipzig Univ. - Herzzentrum (Germany). Abt. fuer Diagnostische und Interventionelle Radiologie; Boehmer-Lasthaus, S. [Siemens Healthcare Sector, Erlangen (Germany). Imaging and Therapy Div.

    2014-12-15

    Purpose: To compare the performance of server-based (CSS) versus stand-alone post-processing software (ES) for the evaluation of cardiovascular CT examinations (cvCT) and to determine the crucial steps. Data of 40 patients (20 patients for coronary artery evaluation and 20 patients prior to transcatheter aortic valve implantation [TAVI]) were evaluated by 5 radiologists with CSS and ES. Data acquisition was performed using a dual-source 128-row CT unit (SOMATOM Definition Flash, Siemens, Erlangen, Germany) and a 64-row CT unit (Brilliance 64, Philips, Hamburg, Germany). The following workflow was evaluated: Data loading, aorta and coronary segmentation, curved multiplanar reconstruction (cMPR) and 3 D volume rendering technique (3D-VRT), measuring of coronary artery stenosis and planimetry of the aortic annulus. The time requirement and subjective quality for the workflow were evaluated. The coronary arteries as well as the TAVI data could be evaluated significantly faster with CSS (5.5 ± 2.9 min and 8.2 ± 4.0 min, respectively) than with ES (13.9 ± 5.2 min and 15.2 ± 10.9 min, respectively, p = 0.01). Segmentation of the aorta (CSS: 1.9 ± 2.0 min, ES: 3.7 ± 3.3 min), generating cMPR of coronaries (CSS: 0.5 ± 0.2 min, ES: 5.1 ± 2.6 min), aorta and iliac vessels (CSS: 0.5 ± 0.4 min and 0.4 ± 0.4 min, respectively, ES: 1.6 ± 0.7 min and 2.8 ± 3 min, respectively) could be performed significantly faster with CSS than with ES with higher quality of cMPR, measuring of coronary stenosis and 3D-VRT (p < 0.05). Evaluation of cvCT can be accomplished significantly faster and better with CSS than with ES. The segmentation remains the most time-consuming workflow step, so optimization of segmentation algorithms could improve performance even further.

  19. STAND-ALONE WIND ENERGY CONVERSION SYSTEM WITH MAXIMUM POWER TRANSFER CONTROL SISTEMA AISLADO DE CONVERSIÓN EÓLICA CON CONTROL DE MÁXIMA TRANSFERENCIA DE POTENCIA

    Directory of Open Access Journals (Sweden)

    Miguel López

    2009-12-01

    Full Text Available A controlled wind generation system for a stand alone application is presented in this paper. A cascaded step-up/step-down power electronic converters topology is proposed to control the wind power system in the whole wind speed range. For the low wind speed range, the control strategy is aimed to follow the wind turbine’s maximal power coefficient by adjusting the generator’s rotational speed. For high wind speeds, the system power regulation is also made by controlling the generator speed. This control is made by the DC/DC power electronic converter, which modifies its input voltage, changing the machine voltage and consequently varying the generator’s rotor speed. The proposed system is validated by computer simulation. The proposed control system shows a good performance for its application in autonomous wind energy systems.Un sistema de generación eólica para una aplicación aislada es presentado en este artículo. Una topología de convertidores electrónicos de potencia elevador y reductor conectados en cascada es propuesta para controlar la producción eólica en todo el rango de velocidades del viento. Para el rango de vientos suaves, la estrategia de control permite seguir el máximo coeficiente de potencia de turbina eólica mediante el ajuste de la velocidad de rotación del generador. En el rango de vientos fuertes, la regulación de la potencia del sistema se hace igualmente por control de la velocidad de giro del generador. La acción de control es realizada mediante el convertidor DC/DC de potencia el cual modifica su tensión de entrada, cambiando así la tensión en los terminales de la máquina y por consecuencia variando la velocidad de rotación del generador. El sistema propuesto es validado mediante simulación por computador. Los resultados muestran que el sistema de control propuesto actúa de buena manera para su aplicación en sistemas autónomos de generación eólica.

  20. Results of instrumented posterolateral fusion in treatment of lumbar spondylolisthesis with and without segmental kyphosis: A retrospective investigation

    Directory of Open Access Journals (Sweden)

    Szu-Yuan Chen

    2015-06-01

    Full Text Available Background: Treatment by posterolateral fusion (PLF with pedicle-screw instrumentation can be unsuccessful in one-segment and low-grade lumbar spondylolisthesis. Segmental kyphosis, either rigid or dynamic, was hypothesized to be one of the factors interfering with the fusion results. Methods: From 2004 to 2005, 239 patients with single-segment and low-grade spondylolisthesis were recruited and divided into two groups: Group 1 consisting of 129 patients without segmental kyphosis and group 2 consisting of 110 patients with segmental kyphosis. All patients underwent instrumented PLF at the same medical institute, and the average follow-up period was 31 ± 19 months. We obtained plain radiographs of the lumbosacral spine with the anteroposterior view, the lateral view, and the dynamic flexion-extension views before the operation and during the follow-ups. The results of PLF in the two groups were then compared. Results: There was no significant difference in the demographic data of the two groups, except for gender distribution. The osseous fusion rates were 90.7% in group 1 and 68.2% in group 2 (p < 0.001. Conclusion: Instrumented PLF resulted in significantly higher osseous fusion rate in patients without segmental kyphosis than in the patients with segmental kyphosis. For the patients with sagittal imbalance, such as rigid or dynamic kyphosis, pedicle-screw fixation cannot ensure successful PLF. Interbody fusion by the posterior lumbar interbody fusion or transforaminal lumbar interbody fusion technique might help overcome this problem.

  1. Anterior cervical discectomy with or without fusion with ray titanium cage: a prospective randomized clinical study

    DEFF Research Database (Denmark)

    Hauerberg, J.; Kosteljanetz, M.; Bøge-Rasmussen, Torben

    2008-01-01

    STUDY DESIGN: A prospective randomized clinical study. OBJECTIVE: To compare 2 surgical methods in the treatment of cervical radiculopathy caused by hard or soft disc herniation; namely, simple discectomy versus discectomy with an additional interbody fusion with a Ray titanium cage. SUMMARY...... by fusion with a Ray titanium cage (40 patients) or to discectomy alone (46 patients). Clinical and radiologic follow-up was performed 3, 12, and 24 months after surgery. RESULTS: There was no statistically significant difference between the 2 groups concerning self-reported satisfaction or severity of pain...... adjacent disc degeneration or spondylosis were the same in both groups. CONCLUSION: This study showed no statistically significant difference between simple discectomy and discectomy followed by interbody fusion with a titanium cage in the surgical treatment of cervical radiculopathy caused by disc...

  2. Does PEEK/HA Enhance Bone Formation Compared With PEEK in a Sheep Cervical Fusion Model?

    Science.gov (United States)

    Walsh, William R; Pelletier, Matthew H; Bertollo, Nicky; Christou, Chris; Tan, Chris

    2016-11-01

    Polyetheretherketone (PEEK) has a wide range of clinical applications but does not directly bond to bone. Bulk incorporation of osteoconductive materials including hydroxyapatite (HA) into the PEEK matrix is a potential solution to address the formation of a fibrous tissue layer between PEEK and bone and has not been tested. Using in vivo ovine animal models, we asked: (1) Does PEEK-HA improve cortical and cancellous bone ongrowth compared with PEEK? (2) Does PEEK-HA improve bone ongrowth and fusion outcome in a more challenging functional ovine cervical fusion model? The in vivo responses of PEEK-HA Enhanced and PEEK-OPTIMA ® Natural were evaluated for bone ongrowth in the form of dowels implanted in the cancellous and cortical bone of adult sheep and examined at 4 and 12 weeks as well as interbody cervical fusion at 6, 12, and 26 weeks. The bone-implant interface was evaluated with radiographic and histologic endpoints for a qualitative assessment of direct bone contact of an intervening fibrous tissue later. Gamma-irradiated cortical allograft cages were evaluated as well. Incorporating HA into the PEEK matrix resulted in more direct bone apposition as opposed to the fibrous tissue interface with PEEK alone in the bone ongrowth as well as interbody cervical fusions. No adverse reactions were found at the implant-bone interface for either material. Radiography and histology revealed resorption and fracture of the allograft devices in vivo. Incorporating HA into PEEK provides a more favorable environment than PEEK alone for bone ongrowth. Cervical fusion was improved with PEEK-HA compared with PEEK alone as well as allograft bone interbody devices. Improving the bone-implant interface with a PEEK device by incorporating HA may improve interbody fusion results and requires further clinical studies.

  3. Test of the scroll pump in the JAERI Fuel Cleanup System in the Tritium Systems Test Assembly. JFCU scroll pump test and result, JFCU stand alone tritium test 2

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Takumi; Konishi, Satoshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Ohira, Shigeru [and others

    1993-03-01

    In the JAERI Fuel Cleanup System (JFCU), major subsystem of the TSTA simulated fusion fuel loop, a Normetex Scroll pump is used to pump out hydrogen isotope gases from the palladium diffuser. The characteristics of the pump was measured with hydrogen isotopes and helium, in a closed loop. Compression ratio and ultimate pressure were strongly affected by the delivery pressure and the species of the gas. Particularly with H{sub 2} and D{sub 2}, additional metal bellows pump was proved to be needed to satisfy the process requirement. For hydrogen isotopes, pumping characteristics improves with the mass of the gas and similar pumping capability was obtained with pure T{sub 2} and helium. (author).

  4. Adjacent Lumbar Disc Herniation after Lumbar Short Spinal Fusion

    OpenAIRE

    Ninomiya, Koshi; Iwatsuki, Koichi; Ohnishi, Yu-ichiro; Ohkawa, Toshika; Yoshimine, Toshiki

    2014-01-01

    A 70-year-old outpatient presented with a chief complaint of sudden left leg motor weakness and sensory disturbance. He had undergone L4/5 posterior interbody fusion with L3–5 posterior fusions for spondylolisthesis 3 years prior, and the screws were removed 1 year later. He has been followed up for 3 years, and there had been no adjacent segment problems before this presentation. Lumbar magnetic resonance imaging (MRI) showed a large L2/3 disc hernia descending to the L3/4 level. Compared to...

  5. Fiscal 2000 regional new energy vision formulation - Financially aided project. Report on regional new energy vision formulation for Ueno village (Object of survey: Commercialization feasibility study for a stand-alone type wind power generation system at Ueno German Culture Village); 2000 nendo Uenoson chiiki shin energy vision sakutei hokokusho. Ueno Doitsu bunkamura dokuritsugata furyoku hatsuden system jigyoka feasibility study chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-02-01

    A survey is conducted about the profitability of installing a stand-alone type wind power system at Ueno village (Miyako Island), Okinawa Prefecture. The German Culture Village, which is an integrated resort house provided with accommodations (500 people), educational and cultural facilities, and sports facilities consumes 272 MWh/year in electric power. The results of the survey are summarized in six chapters, which are (1) the survey of the business under the project to be the object of feasibility study, (2) project to be the object of feasibility study, (3) outline of the Okinawa Electric Power Co., Inc., Miyakojima system and problems to ensue from its interconnection with wind turbines, (4) survey of stand-alone type wind turbine power generation systems, (5) technical/economic feasibility study, and (6) project management and future tasks. It is concluded that there will be profit in the presence of a subsidy that covers 65% or more of the total cost of constructing a system comprising three 600 KW wind turbines, three 400 kW class diesel generators, and storage batteries. (NEDO)

  6. Alternative route of process modification for biofuel production by embedding the Fischer-Tropsch plant in existing stand-alone power plant (10 MW) based on biomass gasification - Part I: A conceptual modeling and simulation approach (a case study in Thailand)

    DEFF Research Database (Denmark)

    Hunpinyo, Piyapong; Cheali, Peam; Narataruksa, Phavanee

    2014-01-01

    a base case process model coupled with techno-economic evaluation for the FT synthesis. In particular, the FT process configurations are designed and assessed using current kinetic laboratory data by our research group for modeling specific reactions in PFR reactor. The calculation of equipment sizing......The utilization of syngas shows a highly potential to improve the economic potential of the stand-alone power unit-based gasification plants as well as enhancing the growing demand of transportation fuels. The thermochemical conversion of biomass via gasification to heat and power generations from...... incurred several major unit operations is performed for once-through mode (no recycles of unconverted syngas) with electricity co-production. This study provides a detailed base-case model for the synthesis with the capacities of 1, 2 and 3 MW of syngas technology sharing and the comparison between...

  7. Study of a stand alone power system based on a photovoltaic field, an electrolyser and a fuel cell: test bench and modelling; Etude d'un systeme autonome de production d'energie couplant un champ photovoltaique, un electrolyseur et une pile a combustible: realisation d'un banc d'essai et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Busquet, S.

    2003-12-01

    Our energetic future has to be based on non-polluting energies with long-term resources. Renewable energies are the best candidates but as their production is intermittent, storage way is necessary as well efficient as environmentally friendly. Coupled an electrolyser and a fuel cell allows to store electricity in gas form and furthermore to produce heat energy. The goal of this work is to evaluate performances of a stand-alone power system, producing electricity and heat, coupling a photovoltaic field and a hydrogen storage system, made of an electrolyser, a gas storage unit and a fuel cell. Hydrogen is the unique way to store electricity. To complete this task, two tools have been developed: a 3,6 kW test bench and a simulation tool. To select the test bench, a bibliographic study enables to collect the necessary information to size and to choice the system and its components. The low availability of components adapted to our application, forces us to create new devices (electrolyser, fuel cell, power management unit). The test bench is automatic and safe. Experimental analysis evaluates the efficiency of the hydrogen storage system, determining the different losses occurring in each component. Modifications are proposed to increase the performances of the storage system. The simulation tool enables to plan the operating of the test bench for a fixed load and place. This model can simulate any system based on experimental data of each component. Simulation results enable to characterise the functioning of the test bench in a stand-alone operation, to determine its performances and to evaluate the influence of the different losses. (author)

  8. Performance evaluation of stand alone hybrid PV-wind generator

    International Nuclear Information System (INIS)

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H.; Yahaya, M. S.

    2015-01-01

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand

  9. Radon Monitoring in Army Stand-Alone Housing Units

    Science.gov (United States)

    1990-04-01

    damage lung tissue and lead I to increased risk of developing lang cancer . Your risk of developing lung cancer from exposure to radon depends upon the...of developing lung cancer than exposure to a significantly elevated level for a short time. In general, your risk increases as the level of radon and...000mm 0Mmm *000 OOO 0 0w 0 0 000 -0-0 *4 0 880 mama 0 0000000000 000 000Eca ( el cN) 00 9 ’ qqO .00 1(10 0 -U M w co SEE wSS SEES NSEwESO m v MM O v mm

  10. Performance evaluation of stand alone hybrid PV-wind generator

    Science.gov (United States)

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H.; Yahaya, M. S.

    2015-05-01

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.

  11. Algal Hydrogen Production -- Stand Alone or Integrated System?

    Energy Technology Data Exchange (ETDEWEB)

    Ghirardi, Maria L.; Maness, Pin Ching; Kosourovo, Sergey

    2016-01-01

    Photosynthetic bacteria and green algae photoproduce H2. but do so utilizing different catalysts and substrates. Green algae use reductant generate mostly by water oxidation to catalyze the reduction of protons to H2 gas, while photosynthetic bacteria catalyze H2 production from organic acids using the nitrogenase enzyme. Moreover, these two organisms utilize different regions of the solar spectrum to perform photosynthesis: green algae's light harvesting antenna is comprised of chlorophyll molecules that absorb mostly blue and red light; photosynthetic bacteria harvest blue and far-red light through their light-harvesting pigments to run its non-oxygenic photosynthetic reactions. There is thus an opportunity to increase the range of solar spectrum used to photoproduce H2 by combining the light-harvesting and catalytic properties of these two organisms in a single process. In the current manuscript, we describe an experimental system that validates this hypothesis and demonstrates quantitatively the advantages of a two organism process for production of higher amounts of H2 and thus achieving solar light conversion efficiencies.

  12. Deterrents on the Over Utilisation of Stand Alone Photovoltaic (PV ...

    African Journals Online (AJOL)

    At inception of the programme, systems were either undersized, or over utilised as clients did not reveal their usage needs in an attempt to reduce costs. This resulted in battery failures and other system breakdowns. The NPVREP categorised systems in order to alleviate the problem of under sizing and/or over utilization of ...

  13. Basic Stand Alone Medicare Claims Public Use Files

    Data.gov (United States)

    U.S. Department of Health & Human Services — CMS is committed to increasing access to its Medicare claims data through the release of de-identified data files available for public use. They contain...

  14. The yeast stands alone: the future of protein biologic production.

    Science.gov (United States)

    Love, Kerry R; Dalvie, Neil C; Love, J Christopher

    2017-12-22

    Yeasts are promising alternative hosts for the manufacturing of recombinant protein therapeutics because they simply and efficiently meet needs for both platform and small-market drugs. Fast accumulation of biomass and low-cost media reduce the cost-of-goods when using yeast, which in turn can enable agile, small-volume manufacturing facilities. Small, tractable yeast genomes are amenable to rapid process development, facilitating strain and product quality by design. Specifically, Pichia pastoris is becoming a widely accepted yeast for biopharmaceutical manufacturing in much of the world owing to a clean secreted product and the rapidly expanding understanding of its cell biology as a host organism. We advocate for a near term partnership spanning industry and academia to promote open source, timely development of yeast hosts. Copyright © 2017. Published by Elsevier Ltd.

  15. Performance evaluation of stand alone hybrid PV-wind generator

    Energy Technology Data Exchange (ETDEWEB)

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H. [Faculty of Electrical Engineering, Universiti Teknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Melaka (Malaysia); Yahaya, M. S. [Faculty of Engineering Technology, Universiti Teknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Melaka (Malaysia)

    2015-05-15

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.

  16. Basic Stand Alone Medicare Prescription Drug Events PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This is a Public Use File for Prescription Drug Events drawn from the 2008 Beneficiary Summary File of Medicare beneficiaries enrolled during the calendar year 2008,...

  17. PV-Battery Sizing for Stand-Alone Lighting Applications

    OpenAIRE

    Herteleer, Bert; Cappelle, Jan; Appels, Reinhart; Lefevre, Buvana; Driesen, Johan; Catthoor, Francky

    2013-01-01

    This paper presents a follow-up and addition to a system sizing spreadsheet, detailed in [An autonomous photovoltaic system sizing program for office applications in Africa], with a focus on sizing or verifying the employability of an off-grid PV-battery system for night lighting. A dimensionless criterion, the Battery Usable Fraction UF_batt is defined, which aids both the calculations of systems and allows an approximate comparison of batteries, regardless of the employed battery chemistry....

  18. She stands alone: Pakistani woman film director, Shireen Pasha.

    Science.gov (United States)

    Mustafa, A

    1995-01-01

    This article describes the activities of film director Shireen Pasha in promoting truth in the mass media in Pakistan. Pasha is described as one who finds it inexcusable in a state-subsidized system that national problems of poverty are not aired openly. Pasha has pursued the goal of exposing the real lives of Pakistanis on film in contrast to the publicly aired segments of "pretty girls in nice drawing rooms." Foreign channels available through satellite communications technology are viewed by Pasha as inappropriate with regard to people's needs and uncreative. Pakistan began with one channel, PTV, which recently refused to air her documentary on living conditions in Pakistan's rural areas "The Travelogue Pakistan." "The Walled City of Lahore" was her film about life in the old city. Both films poetically depicted the honor of humans and their struggle to stay alive. Some of her documentaries are made to show the value of indigenous skills, centuries old know-how, and traditions, regardless of the poverty. Pasha is described as fighting with PTV management over use of resources. Pasha desires to invest in training people to do documentaries or be more field-oriented rather than investing in equipment. Pasha joined PTV in 1975 and left in 1990. Pasha is recognized for her isolation as a woman in the business world, her commitment to exposing remote cultures and truth, and the odds she must confront in attaining her goals. Pasha is committed to doing extensive research, usually conducted during the summer months, in order to construct a credible story line that is produced usually during the winter months. One model of film story line is defined as one where women are portrayed as starting from an indigenous skill or knowledge and shifting to a greater position of power and control over their lives. Pasha believes that people who make films have the responsibility to evoke a reaction in people and to offer solutions. Two acclaimed films, which were supported by USAID and the government, were "Before It's Too Late" and "Only One Way." Both deal with resource issues and the environment. She is currently director of her own film house, The Film Makers, in Lahore. After graduating from the National College of Arts in 1968, she furthered her education in the US in the history of art.

  19. Constraining lidar stand-alone retrievals with lunar photometry measurements

    Science.gov (United States)

    Ortiz-Amezcua, Pablo; Luis Guerrero-Rascado, Juan; Antonio Benavent-Oltra, Jose; Román, Roberto; Böckmann, Christine; Alados-Arboledas, Lucas

    2018-04-01

    This study combines atmospheric optical information measured with lidar and nocturnal photometers in order to find configurations that allow for the retrieval of particle microphysical properties without "3+2" lidar setups. It has been carried out using data measured at the EARLINET Granada station during the experimental campaign SLOPE in the framework of ACTRIS-2 project.

  20. A calcium phosphate implant with controlled macroporosity for anterior L5-S1 interbody fusion

    OpenAIRE

    Charrière, Eric; Zysset, Philippe

    2005-01-01

    In the United States approximately 50 million people suffer from low back pain. In the 20-50 years age group, this is the most important and expensive health care problem. The causes of low back pain are various. A herniated disk or spinal stenosis may trap nerve roots exiting the spinal column. Spondylolisthesis or degenerative disorders affecting the facet joints may cause some spinal units to become unstable. Although the majority of patients suffering back pain respond well to conservativ...

  1. Biomechanical evaluation of a spherical lumbar interbody device at varying levels of subsidence.

    Science.gov (United States)

    Rundell, Steven A; Isaza, Jorge E; Kurtz, Steven M

    2011-01-01

    Ulf Fernström implanted stainless steel ball bearings following discectomy, or for painful disc disease, and termed this procedure disc arthroplasty. Today, spherical interbody spacers are clinically available, but there is a paucity of associated biomechanical testing. The primary objective of the current study was to evaluate the biomechanics of a spherical interbody implant. It was hypothesized that implantation of a spherical interbody implant, with combined subsidence into the vertebral bodies, would result in similar ranges of motion (RoM) and facet contact forces (FCFs) when compared with an intact condition. A secondary objective of this study was to determine the effect of using a polyetheretherketone (PEEK) versus a cobalt chrome (CoCr) implant on vertebral body strains. We hypothesized that the material selection would have a negligible effect on vertebral body strains since both materials have elastic moduli substantially greater than the annulus. A finite element model of L3-L4 was created and validated by use of ROM, disc pressure, and bony strain from previously published data. Virtual implantation of a spherical interbody device was performed with 0, 2, and 4 mm of subsidence. The model was exercised in compression, flexion, extension, axial rotation, and lateral bending. The ROM, vertebral body effective (von Mises) strain, and FCFs were reported. Implantation of a PEEK implant resulted in slightly lower strain maxima when compared with a CoCr implant. For both materials, the peak strain experienced by the underlying bone was reduced with increasing subsidence. All levels of subsidence resulted in ROM and FCFs similar to the intact model. The results suggest that a simple spherical implant design is able to maintain segmental ROM and provide minimal differences in FCFs. Large areas of von Mises strain maxima were generated in the bone adjacent to the implant regardless of whether the implant was PEEK or CoCr.

  2. Does adding interbody fusion to posterolateral fusion increase success in the surgical management of degenerative lumbar spondylolisthesis?

    Directory of Open Access Journals (Sweden)

    Arturo Meissner-Haecker

    2018-01-01

    Full Text Available Resumen INTRODUCCIÓN Frecuentemente se agrega una artrodesis intersomática a la artrodesis posterolateral en el tratamiento quirúrgico de la espondilolistesis degenerativa. Sin embargo, la real utilidad de esta medida no está clara. MÉTODOS Para responder esta pregunta utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES Identificamos cuatro revisiones sistemáticas que en conjunto incluyen nueve estudios primarios, de los cuales ninguno corresponde a un ensayo aleatorizado. Concluimos que agregar una artrodesis intersomática a una artrodesis posterolateral en el tratamiento quirúrgico de la espondilolistesis degenerativa podría asociarse a una disminución en el deslizamiento del cuerpo vertebral y a una leve mejoría de la calidad de vida de los pacientes, pero asociado también a un mayor costo.

  3. Fusion Rates of Different Anterior Grafts in Thoracolumbar Fractures.

    Science.gov (United States)

    Antoni, Maxime; Charles, Yann Philippe; Walter, Axel; Schuller, Sébastien; Steib, Jean-Paul

    2015-11-01

    Retrospective CT analysis of anterior fusion in thoracolumbar trauma. The aim of this study was to compare fusion rates of different bone grafts and to analyze risk factors for pseudarthrosis. Interbody fusion is indicated in anterior column defects. Different grafts are used: autologous iliac crest, titanium mesh cages filled with cancellous bone, and autologous ribs. It is not clear which graft offers the most reliable fusion. Radiologic data of 116 patients (71 men, 45 women) operated for type A2, A3, B, or C fractures were analyzed. The average age was 44.6 years (range, 16-75 y) and follow-up was 2.7 years (range, 1-9 y). All patients were treated by posterior instrumentation followed by an anterior graft: 53 cases with iliac crest, 43 cases with mesh cages, and 20 with rib grafts. Fusion was evaluated on CT and classified into complete fusion, partial fusion, unipolar pseudarthrosis, and bipolar pseudarthrosis. Iliac crest fused in 66%, cages in 98%, and rib grafts in 90%. The fusion rate of cages filled with bone was significantly higher as the iliac graft fusion rate (P=0.002). The same was applied to rib grafts compared with iliac crest (P=0.041). Additional bone formation around the main graft, bridging both vertebral bodies, was observed in 31 of the 53 iliac crests grafts. Pseudarthrosis occurred more often in smokers (P=0.042). A relationship between fracture or instrumentation types, sex, age, BMI, and fusion could not be determined. Tricortical iliac crest grafts showed an unexpected high pseudarthrosis rate in thoracolumbar injuries. Their cortical bone is dense and their fusion surface is small. Rib grafts led to a better fusion when used in combination with the cancellous bone from the fractured vertebral body. Titanium mesh cages filled with cancellous bone led to the highest fusion rate and built a complete bony bridge between vertebral bodies. Smoking seemed to influence fusion. Case control study, Level III.

  4. Fusion energy

    International Nuclear Information System (INIS)

    Gross, R.A.

    1984-01-01

    This textbook covers the physics and technology upon which future fusion power reactors will be based. It reviews the history of fusion, reaction physics, plasma physics, heating, and confinement. Descriptions of commercial plants and design concepts are included. Topics covered include: fusion reactions and fuel resources; reaction rates; ignition, and confinement; basic plasma directory; Tokamak confinement physics; fusion technology; STARFIRE: A commercial Tokamak fusion power plant. MARS: A tandem-mirror fusion power plant; and other fusion reactor concepts

  5. Intervertebral Fusion with Mobile Microendoscopic Discectomy for Lumbar Degenerative Disc Disease.

    Science.gov (United States)

    Xu, Bao-Shan; Liu, Yue; Xu, Hai-Wei; Yang, Qiang; Ma, Xin-Long; Hu, Yong-Cheng

    2016-05-01

    The aim of this article is to introduce a technique for lumbar intervertebral fusion that incorporates mobile microendoscopic discectomy (MMED) for lumbar degenerative disc disease. Minimally invasive transforaminal lumbar interbody fusion is frequently performed to treat degenerative diseases of the lumbar spine; however, the scope of such surgery and vision is limited by what the naked eye can see through the expanding channel system. To expand the visual scope and reduce trauma, we perform lumbar intervertebral fusion with the aid of a MMED system that provides a wide field through freely tilting the surgical instrument and canals. We believe that this technique is a good option for treating lumbar degenerative disc disease that requires lumbar intervertebral fusion. © 2016 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

  6. Adjacent Lumbar Disc Herniation after Lumbar Short Spinal Fusion

    Directory of Open Access Journals (Sweden)

    Koshi Ninomiya

    2014-01-01

    Full Text Available A 70-year-old outpatient presented with a chief complaint of sudden left leg motor weakness and sensory disturbance. He had undergone L4/5 posterior interbody fusion with L3–5 posterior fusions for spondylolisthesis 3 years prior, and the screws were removed 1 year later. He has been followed up for 3 years, and there had been no adjacent segment problems before this presentation. Lumbar magnetic resonance imaging (MRI showed a large L2/3 disc hernia descending to the L3/4 level. Compared to the initial MRI, this hernia occurred in an “intact” disc among multilevel severely degenerated discs. Right leg paresis and bladder dysfunction appeared a few days after admission. Microscopic lumbar disc herniotomy was performed. The right leg motor weakness improved just after the operation, but the moderate left leg motor weakness and difficulty in urination persisted.

  7. Alternative route of process modification for biofuel production by embedding the Fischer–Tropsch plant in existing stand-alone power plant (10 MW) based on biomass gasification – Part I: A conceptual modeling and simulation approach (a case study in Thailand)

    International Nuclear Information System (INIS)

    Hunpinyo, Piyapong; Cheali, Peam; Narataruksa, Phavanee; Tungkamani, Sabaithip; Chollacoop, Nuwong

    2014-01-01

    Graphical abstract: SynBiofuel production through existing gasification plants in Thailand, using waste agricultural biomass as raw material, was studied. The process design was initiated conceptually in the areas of gas phase reaction system via Fischer-Tropsch (FT) synthesis. The development of FT configurations on syngas conversion to transportation fuels (e.g., diesel range) was investigated. In order to develop a techno-economic assessment, the three different capacities corresponding to 1 MW, 2 MW and 3 MW based on thermal input of syngas were evaluated. Once-through FT concept was proposed in which the unconverted syngas was combusted with air in an externally fired gas turbine (EFGT) to produce surplus electricity. The results of process simulation were discussed open-mindedly including the overall plant design and energy efficiency. Preliminary economics, and some site specific situations under which additional capital cost savings on existing infrastructure was realized. - Highlights: • Experimental results were used and integrated with a reactor model for SynBiofuel. • Process simulation with the lumped reaction rate was used to achieve accurate results. • Process simulation was performed using ASPEN Plus to design FT configurations. • Maximum energy FT efficiency was approximately 37%. • Economic potential was computed by ROI and PBP resulting in the attractive solutions. - Abstract: The utilization of syngas shows a highly potential to improve the economic potential of the stand-alone power unit-based gasification plants as well as enhancing the growing demand of transportation fuels. The thermochemical conversion of biomass via gasification to heat and power generations from the earlier study is further enhanced by integrating Fischer–Tropsch (FT) synthesis with the existing gasification pilot scale studied previously. To support the potential and perspectives in major economies due to scaling up in developing countries such as Thailand

  8. EMP Fusion

    OpenAIRE

    KUNTAY, Isık

    2010-01-01

    This paper introduces a novel fusion scheme, called EMP Fusion, which has the promise of achieving breakeven and realizing commercial fusion power. The method is based on harnessing the power of an electromagnetic pulse generated by the now well-developed flux compression technology. The electromagnetic pulse acts as a means of both heating up the plasma and confining the plasma, eliminating intermediate steps. The EMP Fusion device is simpler compared to other fusion devices and this reduces...

  9. Non-fusion rates in anterior cervical discectomy and implantation of empty polyetheretherketone cages.

    Science.gov (United States)

    Pechlivanis, Ioannis; Thuring, Theresa; Brenke, Christopher; Seiz, Marcel; Thome, Claudius; Barth, Martin; Harders, Albrecht; Schmieder, Kirsten

    2011-01-01

    A prospective analysis. Our aim was to assess the radiographically detectable bony fusion in patients with anterior cervical discectomy (ACD) and polyetheretherketone (PEEK)-cage implantation without additional filling. Furthermore, clinical data of patients with and without fusion were compared. PEEK-cage implantation is performed in cervical spinal surgery because of its benefits. However, fusion rates without filling of the cage have not been reported. Patients selected for ACD with PEEK-cage implantation prospectively underwent plain radiography in anterior-posterior and lateral projections during the postoperative hospital stay and at follow-up. Furthermore, clinical status was evaluated using the Odom scale, the Short Form-36, the Visual Analog Scale (VAS) for arm and neck pain, and the cervical Oswestry score. Fusion status, migration, and subsidence of the PEEK cage were evaluated on the basis of the lateral radiographs. Fusion was confirmed by presence of continuous trabecular bone bridges in the disc space. To exclude an influence of the cage on the evaluation of fusion rates, fusion was evaluated in analogous fashion retrospectively in a control group. A total of 52 patients underwent ACD and interbody fusion. One-level surgery was performed in 44 patients and 2-level surgery in 8 patients. A total of 60 ACD and interbody fusions with a PEEK cage were analyzed. A majority of operations were at the C5/6 level (40 patients, 77%). Cage height was 4 mm in 32 cases, 5 mm in 23 cases, and 6 mm in 5 cases. Bony fusion was present at 43 treated levels (71.7%), whereas at 17 levels (28.3%) no fusion was found. Statistical analysis revealed no significant difference between the fusion and non-fusion groups regarding time to follow-up, implanted cage height. Short Form-36, cervical Oswestry score, VAS arm and neck, or Odom criteria. In the control group, ACD was performed in 29 patients (42 levels; 18 one-level and 12 two-level operations). Bony fusion was present

  10. Techniques of lumbar-sacral spine fusion in spondylosis: systematic literature review and meta-analysis of randomized clinical trials.

    Science.gov (United States)

    Umeta, Ricardo S G; Avanzi, Osmar

    2011-07-01

    Spine fusions can be performed through different techniques and are used to treat a number of vertebral pathologies. However, there seems to be no consensus regarding which technique of fusion is best suited to treat each distinct spinal disease or group of diseases. To study the effectiveness and complications of the different techniques used for spinal fusion in patients with lumbar spondylosis. Systematic literature review and meta-analysis. Randomized clinical studies comparing the most commonly performed surgical techniques for spine fusion in lumbar-sacral spondylosis, as well as those reporting patient outcome were selected. Identify which technique, if any, presents the best clinical, functional, and radiographic outcome. Systematic literature review and meta-analysis based on scientific articles published and indexed to the following databases: PubMed (1966-2009), Cochrane Collaboration-CENTRAL, EMBASE (1980-2009), and LILACS (1982-2009). The general search strategy focused on the surgical treatment of patients with lumbar-sacral spondylosis. Eight studies met the inclusion criteria and were selected with a total of 1,136 patients. Meta-analysis showed that patients who underwent interbody fusion presented a significantly smaller blood loss (p=.001) and a greater rate of bone fusion (p=.02). Patients submitted to fusion using the posterolateral approach had a significantly shorter operative time (p=.007) and less perioperative complications (p=.03). No statistically significant difference was found for the other studied variables (pain, functional impairment, and return to work). The most commonly used techniques for lumbar spine fusion in patients with spondylosis were interbody fusion and posterolateral approach. Both techniques were comparable in final outcome, but the former presented better rates of fusion and the latter the less complications. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Osteoclast Fusion

    DEFF Research Database (Denmark)

    Marie Julie Møller, Anaïs; Delaissé, Jean-Marie; Søe, Kent

    2017-01-01

    on the nuclearity of fusion partners. While CD47 promotes cell fusions involving mono-nucleated pre-osteoclasts, syncytin-1 promotes fusion of two multi-nucleated osteoclasts, but also reduces the number of fusions between mono-nucleated pre-osteoclasts. Furthermore, CD47 seems to mediate fusion mostly through...... individual fusion events using time-lapse and antagonists of CD47 and syncytin-1. All time-lapse recordings have been studied by two independent observers. A total of 1808 fusion events were analyzed. The present study shows that CD47 and syncytin-1 have different roles in osteoclast fusion depending...... broad contact surfaces between the partners' cell membrane while syncytin-1 mediate fusion through phagocytic-cup like structure. J. Cell. Physiol. 9999: 1-8, 2016. © 2016 Wiley Periodicals, Inc....

  12. Fusion power

    International Nuclear Information System (INIS)

    Hancox, R.

    1981-01-01

    The principles of fusion power, and its advantages and disadvantages, are outlined. Present research programmes and future plans directed towards the development of a fusion power reactor, are summarized. (U.K.)

  13. Fusion rings and fusion ideals

    DEFF Research Database (Denmark)

    Andersen, Troels Bak

    by the so-called fusion ideals. The fusion rings of Wess-Zumino-Witten models have been widely studied and are well understood in terms of precise combinatorial descriptions and explicit generating sets of the fusion ideals. They also appear in another, more general, setting via tilting modules for quantum......This dissertation investigates fusion rings, which are Grothendieck groups of rigid, monoidal, semisimple, abelian categories. Special interest is in rational fusion rings, i.e., fusion rings which admit a finite basis, for as commutative rings they may be presented as quotients of polynomial rings...

  14. Fusion: introduction

    International Nuclear Information System (INIS)

    Decreton, M.

    2006-01-01

    The article gives an overview and introduction to the activities of SCK-CEN's research programme on fusion. The decision to construct the ITER international nuclear fusion experiment in Cadarache is highlighted. A summary of the Belgian contributions to fusion research is given with particular emphasis on studies of radiation effects on diagnostics systems, radiation effects on remote handling sensing systems, fusion waste management and socio-economic studies

  15. Membrane fusion

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    At Stanford University, Boxer lab, I worked on membrane fusion of small unilamellar lipid vesicles to flat membranes tethered to glass surfaces. This geometry closely resembles biological systems in which liposomes fuse to plasma membranes. The fusion mechanism was studied using DNA zippering...... between complementary strands linked to the two apposing membranes closely mimicking the zippering mechanism of SNARE fusion complexes....

  16. Fusion Canada

    International Nuclear Information System (INIS)

    1987-07-01

    This first issue of a quarterly newsletter announces the startup of the Tokamak de Varennes, describes Canada's national fusion program, and outlines the Canadian Fusion Fuels Technology Program. A map gives the location of the eleven principal fusion centres in Canada. (L.L.)

  17. Fusion neutronics

    CERN Document Server

    Wu, Yican

    2017-01-01

    This book provides a systematic and comprehensive introduction to fusion neutronics, covering all key topics from the fundamental theories and methodologies, as well as a wide range of fusion system designs and experiments. It is the first-ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators, fusion systems are normally characterized by their complex geometry and nuclear physics, which entail new challenges for neutronics such as complicated modeling, deep penetration, low simulation efficiency, multi-physics coupling, etc. The book focuses on the neutronics characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics, and which have since been widely applied all over the world. Further, it introduces readers to neutronics design’s unique principles and procedures, experimental methodologies and technologies for fusion systems...

  18. Comparison of Expandable and Fixed Interbody Cages in a Human Cadaver Corpectomy Model: Fatigue Characteristics.

    Science.gov (United States)

    Pekmezci, Murat; Tang, Jessica A; Cheng, Liu; Modak, Ashin; McClellan, Robert T; Buckley, Jenni M; Ames, Christopher P

    2016-11-01

    In vitro cadaver biomechanics study. The goal of this study is to compare the in situ fatigue life of expandable versus fixed interbody cage designs. Expandable cages are becoming more popular, in large part, due to their versatility; however, subsidence and catastrophic failure remain a concern. This in vitro analysis investigates the fatigue life of expandable and fixed interbody cages in a single level human cadaver corpectomy model by evaluating modes of subsidence of expandable and fixed cages as well as change in stiffness of the constructs with cyclic loading. Nineteen specimens from 10 human thoracolumbar spines (T10-L2, L3-L5) were biomechanically evaluated after a single level corpectomy that was reconstructed with an expandable or fixed cage and anterior dual rod instrumentation. All specimens underwent 98 K cycles to simulate 3 months of postoperative weight bearing. In addition, a third group with hyperlordotic cages was used to simulate catastrophic failure that is observed in clinical practice. Three fixed and 2 expandable cages withstood the cyclic loading despite perfect sagittal and coronal plane fitting of the endcaps. The majority of the constructs settled in after initial subsidence. The catastrophic failures that were observed in clinical practice could not be reproduced with hyperlordotic cages. However, all cages in this group subsided, and 60% resulted in endplate fractures during deployment of the cage. Despite greater surface contact area, expandable cages have a trend for higher subsidence rates when compared with fixed cages. When there is edge loading as in the hyperlordotic cage scenario, there is a higher risk of subsidence and intraoperative fracture during deployment of expandable cages.

  19. [Subsidence and its effects on the anterior plate stabilization in the course of cervical interbody spondylodesis. Part II. Clinical evaluation. Study design].

    Science.gov (United States)

    Hakało, Jerzy; Wroński, Jerzy

    2003-01-01

    Subsidence is a common phenomenon in the process of interbody fusion. The paper presents a retrospective clinical and radiological evaluation of subsidence in a group of 23 patients after cervical corpectomy with mesh cage and plate stabilization. Subsidence magnitude and its impact on the stabilizing system and on the clinical and radiological outcome were estimated. The mesh cage and cervical plate stabilization was preformed after one- (20 cases) or two-level (3 cases) corpectomy. The patients' mean age was 35 years (age range 18-72); 9 patients were aged over 50. Indications to corpectomy were: neurological impairment due to burst body fractures in 14 cases, multilevel spondylosis in 5, and OPLL in 2 patients. One patient had a kidney cancer metastasis. The mean follow-up period was 17 months (range 12-28 mo.). The patients' clinical status was evaluated using the ASIA scale in the post-traumatic group, and the Odom criteria in spondylotic cases. In all the cases pain severity was estimated by the VAS scale. Magnitude of subsidence was measured on consecutive lateral x-rays during the follow-up. Bone fusion was confirmed after 3 months in lateral flexion-extension x-rays. Changes in the local and general cervical lordosis were evaluated during the follow-up. A 72-year-old patient died after 6 weeks due to causes unrelated to the surgery. In all the remaining patients bone fusion was attained. There were no cases of the clinical status deterioration during the follow-up. Subsidence of over 1 mm was found in 19 patients (86.4%). The mean value of subsidence was 2.2 mm, but in a group of older patients (aged over 50) it amounted to 2.8 mm. In 4 cases (18.1%) with hardware complications, i.e. a screw breakage or slipping, the mean subsidence magnitude was 4.3 mm. Local and general cervical lordosis were maintained during the follow-up period, even in the group with excessive subsidence. The screw breakage site was invariably the round hole of the plate. The

  20. Fusion Physics

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Mitsuru; Lackner, Karl; Tran, Minh Quang [eds.

    2012-09-15

    Recreating the energy production process of the Sun - nuclear fusion - on Earth in a controlled fashion is one of the greatest challenges of this century. If achieved at affordable costs, energy supply security would be greatly enhanced and environmental degradation from fossil fuels greatly diminished. Fusion Physics describes the last fifty years or so of physics and research in innovative technologies to achieve controlled thermonuclear fusion for energy production. The International Atomic Energy Agency (IAEA) has been involved since its establishment in 1957 in fusion research. It has been the driving force behind the biennial conferences on Plasma Physics and Controlled Thermonuclear Fusion, today known as the Fusion Energy Conference. Hosted by several Member States, this biennial conference provides a global forum for exchange of the latest achievements in fusion research against the backdrop of the requirements for a net energy producing fusion device and, eventually, a fusion power plant. The scientific and technological knowledge compiled during this series of conferences, as well as by the IAEA Nuclear Fusion journal, is immense and will surely continue to grow in the future. It has led to the establishment of the International Thermonuclear Experimental Reactor (ITER), which represents the biggest experiment in energy production ever envisaged by humankind.

  1. Fusion breeder

    International Nuclear Information System (INIS)

    Moir, R.W.

    1982-01-01

    The fusion breeder is a fusion reactor designed with special blankets to maximize the transmutation by 14 MeV neutrons of uranium-238 to plutonium or thorium to uranium-233 for use as a fuel for fission reactors. Breeding fissile fuels has not been a goal of the US fusion energy program. This paper suggests it is time for a policy change to make the fusion breeder a goal of the US fusion program and the US nuclear energy program. The purpose of this paper is to suggest this policy change be made and tell why it should be made, and to outline specific research and development goals so that the fusion breeder will be developed in time to meet fissile fuel needs

  2. Fusion Implementation

    International Nuclear Information System (INIS)

    Schmidt, J.A.

    2002-01-01

    If a fusion DEMO reactor can be brought into operation during the first half of this century, fusion power production can have a significant impact on carbon dioxide production during the latter half of the century. An assessment of fusion implementation scenarios shows that the resource demands and waste production associated with these scenarios are manageable factors. If fusion is implemented during the latter half of this century it will be one element of a portfolio of (hopefully) carbon dioxide limiting sources of electrical power. It is time to assess the regional implications of fusion power implementation. An important attribute of fusion power is the wide range of possible regions of the country, or countries in the world, where power plants can be located. Unlike most renewable energy options, fusion energy will function within a local distribution system and not require costly, and difficult, long distance transmission systems. For example, the East Coast of the United States is a prime candidate for fusion power deployment by virtue of its distance from renewable energy sources. As fossil fuels become less and less available as an energy option, the transmission of energy across bodies of water will become very expensive. On a global scale, fusion power will be particularly attractive for regions separated from sources of renewable energy by oceans

  3. Thermonuclear fusion

    International Nuclear Information System (INIS)

    Weisse, J.

    2000-01-01

    This document takes stock of the two ways of thermonuclear fusion research explored today: magnetic confinement fusion and inertial confinement fusion. The basic physical principles are recalled first: fundamental nuclear reactions, high temperatures, elementary properties of plasmas, ignition criterion, magnetic confinement (charged particle in a uniform magnetic field, confinement and Tokamak principle, heating of magnetized plasmas (ohmic, neutral particles, high frequency waves, other heating means), results obtained so far (scale laws and extrapolation of performances, tritium experiments, ITER project), inertial fusion (hot spot ignition, instabilities, results (Centurion-Halite program, laser experiments). The second part presents the fusion reactor and its associated technologies: principle (tritium production, heat source, neutron protection, tritium generation, materials), magnetic fusion (superconducting magnets, divertor (role, principle, realization), inertial fusion (energy vector, laser adaptation, particle beams, reaction chamber, stresses, chamber concepts (dry and wet walls, liquid walls), targets (fabrication, injection and pointing)). The third chapter concerns the socio-economic aspects of thermonuclear fusion: safety (normal operation and accidents, wastes), costs (costs structure and elementary comparison, ecological impact and external costs). (J.S.)

  4. Fusion devices

    International Nuclear Information System (INIS)

    Fowler, T.K.

    1977-01-01

    Three types of thermonuclear fusion devices currently under development are reviewed for an electric utilities management audience. Overall design features of laser fusion, tokamak, and magnetic mirror type reactors are described and illustrated. Thrusts and trends in current research on these devices that promise to improve performance are briefly reviewed. Twenty photographs and drawings are included

  5. Local bone graft harvesting and volumes in posterolateral lumbar fusion: a technical report.

    Science.gov (United States)

    Carragee, Eugene J; Comer, Garet C; Smith, Micah W

    2011-06-01

    In lumbar surgery, local bone graft is often harvested and used in posterolateral fusion procedures. The volume of local bone graft available for posterolateral fusion has not been determined in North American patients. Some authors have described this as minimal, but others have suggested the volume was sufficient to be reliably used as a stand-alone bone graft substitute for single-level fusion. To describe the technique used and determine the volume of local bone graft available in a cohort of patients undergoing single-level primary posterolateral fusion by the authors harvesting technique. Technical description and cohort report. Consecutive patients undergoing lumbar posterolateral fusion with or without instrumentation for degenerative processes. Local bone graft volume. Consecutive patients undergoing lumbar posterolateral fusion with or without instrumentation for degenerative processes of were studied. Local bone graft was harvested by a standard method in each patient and the volume measured by a standard procedure. Twenty-five patients were studied, and of these 11 (44%) had a previous decompression. The mean volume of local bone graft harvested was measured to be 25 cc (range, 12-36 cc). Local bone graft was augmented by iliac crest bone in six of 25 patients (24%) if the posterolateral fusion bed was not well packed with local bone alone. There was a trend to greater local bone graft volumes in men and in patients without previous decompression. Large volumes of local bone can be harvested during posterolateral lumbar fusion surgery. Even in patients with previous decompression the volume harvested is similar to that reported harvested from the posterior iliac crest for single-level fusion. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Pseudarthrosis after lumbar spinal fusion: the role of {sup 18}F-fluoride PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Marloes; Willems, Paul; Jutten, Liesbeth; Arts, Chris; Rhijn, Lodewijk van [Maastricht University Medical Center, Department of Orthopedic Surgery, Postbox 5800, Maastricht (Netherlands); Weijers, Rene; Wierts, Roel; Urbach, Christian; Brans, Boudewijn [Maastricht University Medical Center, Radiology /Nuclear Medicine, Maastricht (Netherlands)

    2015-11-15

    Painful pseudarthrosis is one of the most important indications for (revision) surgery after spinal fusion procedures. If pseudarthrosis is the source of recurrent pain it may require revision surgery. It is therefore of great clinical importance to ascertain if it is the source of such pain. The correlation between findings on conventional imaging (plain radiography and CT) and clinical well-being has been shown to be moderate. The goal of this study was to determine the possible role of {sup 18}F-fluoride PET in patients after lumbar spinal interbody fusion by investigating the relationship between PET/CT findings and clinical function and pain. A cohort of 36 patients was retrospectively included in the study after {sup 18}F-fluoride PET/CT for either persistent or recurrent low back pain (18 patients) or during routine postoperative investigation (18 patients) between 9 and 76 months and 11 and 14 months after posterior lumbar interbody fusion, respectively. Sixty minutes after intravenous injection of 156 - 263 MBq (mean 199 MBq, median 196 MBq) {sup 18}F-fluoride, PET and CT images were acquired using an integrated PET/CT scanner, followed by a diagnostic CT scan. Two observers independently scored the images. The number of bony bridges between vertebrae was scored on the CT images to quantify interbody fusion (0, 1 or 2). Vertebral endplate and intervertebral disc space uptake were evaluated visually as well as semiquantitatively following {sup 18}F-fluoride PET. Findings on PET and CT were correlated with clinical wellbeing as measured by validated questionnaires concerning general daily functioning (Oswestry Disability Index), pain (visual analogue scale) and general health status (EuroQol). Patients were divided into three categories based on these questionnaire scores. No correlation was found between symptom severity and fusion status. However, {sup 18}F-fluoride activity in the vertebral endplates was significantly higher in patients in the lowest

  7. Pseudarthrosis after lumbar spinal fusion: the role of 18F-fluoride PET/CT

    International Nuclear Information System (INIS)

    Peters, Marloes; Willems, Paul; Jutten, Liesbeth; Arts, Chris; Rhijn, Lodewijk van; Weijers, Rene; Wierts, Roel; Urbach, Christian; Brans, Boudewijn

    2015-01-01

    Painful pseudarthrosis is one of the most important indications for (revision) surgery after spinal fusion procedures. If pseudarthrosis is the source of recurrent pain it may require revision surgery. It is therefore of great clinical importance to ascertain if it is the source of such pain. The correlation between findings on conventional imaging (plain radiography and CT) and clinical well-being has been shown to be moderate. The goal of this study was to determine the possible role of 18 F-fluoride PET in patients after lumbar spinal interbody fusion by investigating the relationship between PET/CT findings and clinical function and pain. A cohort of 36 patients was retrospectively included in the study after 18 F-fluoride PET/CT for either persistent or recurrent low back pain (18 patients) or during routine postoperative investigation (18 patients) between 9 and 76 months and 11 and 14 months after posterior lumbar interbody fusion, respectively. Sixty minutes after intravenous injection of 156 - 263 MBq (mean 199 MBq, median 196 MBq) 18 F-fluoride, PET and CT images were acquired using an integrated PET/CT scanner, followed by a diagnostic CT scan. Two observers independently scored the images. The number of bony bridges between vertebrae was scored on the CT images to quantify interbody fusion (0, 1 or 2). Vertebral endplate and intervertebral disc space uptake were evaluated visually as well as semiquantitatively following 18 F-fluoride PET. Findings on PET and CT were correlated with clinical wellbeing as measured by validated questionnaires concerning general daily functioning (Oswestry Disability Index), pain (visual analogue scale) and general health status (EuroQol). Patients were divided into three categories based on these questionnaire scores. No correlation was found between symptom severity and fusion status. However, 18 F-fluoride activity in the vertebral endplates was significantly higher in patients in the lowest Oswestry Disability Index

  8. Tools and methods for implementing the control systems on the Mirror Fusion Test Facility

    International Nuclear Information System (INIS)

    Minor, E.G.; Labiak, W.G.

    1981-01-01

    Installation of the major hardware subsystems for MFTF is nearing completion. These subsystems include the Fusion Chamber System, the eighty KV Neutral Beam System, the Superconducting Magnet System, and the Personnel Safety System. The Local Controls group has undertaken a uniform aproach to implementing the control systems for all of these hardware subsystems. This approach has two major aspects: (1) to provide a stand-alone computer control system with a remote, portable terminal so that computer control can be provided at the site of the hardware for initial testing, (2) to provide hardware simulators so that the complicated MFTF computer control system can be tested independent of the hardware. The software and hardware tools which were developed to carry out this plan will be described. Our experiences with bringing up subsystems containing up to 900 separate channels of control and status will also be described

  9. Atomic fusion, Gerrard atomic fusion

    International Nuclear Information System (INIS)

    Gerrard, T.H.

    1980-01-01

    In the approach to atomic fusion described here the heat produced in a fusion reaction, which is induced in a chamber by the interaction of laser beams and U.H.F. electromagnetic beams with atom streams, is transferred to a heat exchanger for electricity generation by a coolant flowing through a jacket surrounding the chamber. (U.K.)

  10. Peaceful fusion

    Energy Technology Data Exchange (ETDEWEB)

    Englert, Matthias [IANUS, TU Darmstadt (Germany)

    2014-07-01

    Like other intense neutron sources fusion reactors have in principle a potential to be used for military purposes. Although the use of fissile material is usually not considered when thinking of fusion reactors (except in fusion-fission hybrid concepts) quantitative estimates about the possible production potential of future commercial fusion reactor concepts show that significant amounts of weapon grade fissile materials could be produced even with very limited amounts of source materials. In this talk detailed burnup calculations with VESTA and MCMATH using an MCNP model of the PPCS-A will be presented. We compare different irradiation positions and the isotopic vectors of the plutonium bred in different blankets of the reactor wall with the liquid lead-lithium alloy replaced by uranium. The technical, regulatory and policy challenges to manage the proliferation risks of fusion power will be addressed as well. Some of these challenges would benefit if addressed at an early stage of the research and development process. Hence, research on fusion reactor safeguards should start as early as possible and accompany the current research on experimental fusion reactors.

  11. Cold fusion

    International Nuclear Information System (INIS)

    Suh, Suk Yong; Sung, Ki Woong; Kang, Joo Sang; Lee, Jong Jik

    1995-02-01

    So called 'cold fusion phenomena' are not confirmed yet. Excess heat generation is very delicate one. Neutron generation is most reliable results, however, the records are erratic and the same results could not be repeated. So there is no reason to exclude the malfunction of testing instruments. The same arguments arise in recording 4 He, 3 He, 3 H, which are not rich in quantity basically. An experiment where plenty of 4 He were recorded is attached in appendix. The problem is that we are trying to search cold fusion which is permitted by nature or not. The famous tunneling effect in quantum mechanics will answer it, however, the most fusion rate is known to be negligible. The focus of this project is on the theme that how to increase that negligible fusion rate. 6 figs, 4 tabs, 1512 refs. (Author)

  12. Cold fusion

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Suk Yong; Sung, Ki Woong; Kang, Joo Sang; Lee, Jong Jik [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-02-01

    So called `cold fusion phenomena` are not confirmed yet. Excess heat generation is very delicate one. Neutron generation is most reliable results, however, the records are erratic and the same results could not be repeated. So there is no reason to exclude the malfunction of testing instruments. The same arguments arise in recording {sup 4}He, {sup 3}He, {sup 3}H, which are not rich in quantity basically. An experiment where plenty of {sup 4}He were recorded is attached in appendix. The problem is that we are trying to search cold fusion which is permitted by nature or not. The famous tunneling effect in quantum mechanics will answer it, however, the most fusion rate is known to be negligible. The focus of this project is on the theme that how to increase that negligible fusion rate. 6 figs, 4 tabs, 1512 refs. (Author).

  13. Laser fusion

    International Nuclear Information System (INIS)

    Ashby, D.E.T.F.

    1976-01-01

    A short survey is given on laser fusion its basic concepts and problems and the present theoretical and experimental methods. The future research program of the USA in this field is outlined. (WBU) [de

  14. CORRECTION OF SEVERE STIFF SCOLIOSIS THROUGH EXTRAPLEURAL INTERBODY RELEASE AND OSTEOTOMY (LIEPO

    Directory of Open Access Journals (Sweden)

    Cleiton Dias Naves

    Full Text Available ABSTRACT Objective: To report a new technique for extrapleural interbody release with transcorporal osteotomy of the inferior vertebral plateau (LIEPO and to evaluate the correction potential of this technique and its complications. Method: We included patients with scoliosis with Cobb angle greater than 90° and flexibility less than 25% submitted to surgical treatment between 2012 and 2016 by the technique LIEPO at the National Institute of Traumatology and Orthopedics (INTO. Sagittal and coronal alignment, and the translation of the apical vertebra were measured and the degree of correction of the deformity was calculated through the pre and postoperative radiographs, and the complications were described. Results: Patients had an average bleed of 1,525 ml, 8.8 hours of surgical time, 123° of scoliosis in the preoperative period, and a mean correction of 66%. There was no case of permanent neurological damage and no surgical revision. Conclusion: The LIEPO technique proved to be effective and safe in the treatment of severe stiff scoliosis, reaching a correction potential close to the PEISR (Posterior extrapleural intervertebral space release technique and superior to that of the pVCR (posterior Vertebral Column Resection with no presence of infection and permanent neurological deficit. New studies are needed to validate this promising technique.

  15. Fusion energy

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    The efforts of the Chemical Technology Division in fusion energy include the areas of fuel handling, processing, and containment. Current studies are concerned largely with the development of vacuum pumps for fusion reactors and experiments and with development and evaluation of techniques for recovering tritium from solid or liquid breeding blankets. In addition, a small effort is devoted to support of the ORNL design of a major Tokamak experiment, The Next Step (TNS)

  16. Laser fusion

    International Nuclear Information System (INIS)

    Key, M.H.; Oxford Univ.

    1990-04-01

    The use of lasers to drive implosions for the purpose of inertially confined fusion is an area of intense activity where progress compares favourably with that made in magnetic fusion and there are significant prospects for future development. In this brief review the basic concept is summarised and the current status is outlined both in the area of laser technology and in the most recent results from implosion experiments. Prospects for the future are also considered. (author)

  17. Radiological and clinical outcomes of novel Ti/PEEK combined spinal fusion cages: a systematic review and preclinical evaluation.

    Science.gov (United States)

    Assem, Yusuf; Mobbs, Ralph J; Pelletier, Matthew H; Phan, Kevin; Walsh, William R

    2017-03-01

    The primary objective of this paper was to provide a systematic review of the available clinical studies of Ti/PEEK combined cages in spinal interbody fusion surgeries, focusing on their radiological and clinical outcomes. A secondary aim was to provide a review and evaluation of the in vitro and preclinical studies reported on Ti/PEEK-coated implants. A systematic search of the literature was performed in March 2015 via three databases: Medline, Embase and Cochrane library. The following key search terms were combined with synonyms to identify relevant articles: "spinal fusion," "PEEK," "titanium" and "cage." The novelty of this intervention translates into a paucity of clinical trials, albeit the results of the seven clinical studies that met the criteria for inclusion are promising. All studies reported rate of fusion as a primary outcome. Two studies reported slightly improved fusion in the experimental Ti/PEEK combination cohort, one study identical fusion (91.7 %) and three studies excellent fusion (96, 100 and 94 %) in the Ti/PEEK cohort, although no differences reached statistical significance. Clinical studies at this early stage demonstrate that Ti/PEEK implants are safe and efficacious, exhibiting similar fusion rates and clinical outcomes compared to the current standard PEEK. There is clinical evidence substantiating the improved radiographic fusion of Ti/PEEK, albeit the differences were not significant. This field is promising, gaining substantial popularity, and further clinical trials are needed in the future to establish Ti/PEEK cages as a mainstay of clinical practice.

  18. Nuclear fusion

    International Nuclear Information System (INIS)

    Al-zaelic, M.M.

    2013-01-01

    Nuclear fusion can be relied on to solve the global energy crisis if the process of limiting the heat produced by the fusion reaction (Plasma) is successful. Currently scientists are progressively working on this aspect whereas there are two methods to limit the heat produced by fusion reaction, the two methods are auto-restriction using laser beam and magnetic restriction through the use of magnetic fields and research is carried out to improve these two methods. It is expected that at the end of this century the nuclear fusion energy will play a vital role in overcoming the global energy crisis and for these reasons, acquiring energy through the use of nuclear fusion reactors is one of the most urge nt demands of all mankind at this time. The conclusion given is that the source of fuel for energy production is readily available and inexpensive ( hydrogen atoms) and whole process is free of risks and hazards, especially to general health and the environment . Nuclear fusion importance lies in the fact that energy produced by the process is estimated to be about four to five times the energy produced by nuclear fission. (author)

  19. Biomechanics of lumbar cortical screw-rod fixation versus pedicle screw-rod fixation with and without interbody support.

    Science.gov (United States)

    Perez-Orribo, Luis; Kalb, Samuel; Reyes, Phillip M; Chang, Steve W; Crawford, Neil R

    2013-04-15

    Seven different combinations of posterior screw fixation, with or without interbody support, were compared in vitro using nondestructive flexibility tests. To study the biomechanical behavior of a new cortical screw (CS) fixation construct relative to the traditional pedicle screw (PS) construct. The CS is an alternative to the PS for posterior fixation of the lumbar spine. The CS trajectory is more sagittally and cranially oriented than the PS, being anchored in the pars interarticularis. Like PS fixation, CS fixation uses interconnecting rods fastened with top-locking connectors. Stability after bilateral CS fixation was compared with stability after bilateral PS fixation in the setting of intact disc and with direct lateral interbody fixation (DLIF) or transforaminal lateral interbody fixation (TLIF) support. Standard nondestructive flexibility tests were performed in cadaveric lumbar specimens, allowing non-paired comparisons of specific conditions from 28 specimens (4 groups of 7) within a larger experiment of multiple hardware configurations. Condition tested and group from which results originated were as follows: (1) intact (all groups); (2) with L3-L4 bilateral PS-rods (group 1); (3) with bilateral CS-rods (group 2); (4) with DLIF (group 3); (5) with DLIF + CS-rods (group 4); (6) with DLIF + PS-rods (group 3); (7) with TLIF + CS-rods (group 2), and (8) with TLIF + PS-rods (group 2). To assess spinal stability, the mean range of motion, lax zone, and stiff zone at L3-L4 were compared during flexion-extension, lateral bending, and axial rotation. With intact disc, stability was equivalent after PS-rod and CS-rod fixation, except that PS-rod fixation was stiffer during axial rotation. With DLIF support, there was no significant difference in stability between PS-rod and CS-rod fixation. With TLIF support, PS-rod fixation was stiffer than CS-rod fixation during lateral bending. Bilateral CS-rod fixation provided about the same stability in cadaveric specimens

  20. Cold fusion