Customized photorefractive keratectomy to correct high ametropia after penetrating keratoplasty: A pilot study

OpenAIRE

De Rosa, Giuseppe; Boccia, Rosa; Santamaria, Carmine; Fabbozzi, Lorenzo; De Rosa, Luigi; Lanza, Michele

2014-01-01

Purpose: To evaluate preliminarily the safety and efficacy of customized photorefractive keratectomy (PRK) to correct ametropia and irregular astigmatism after penetrating keratoplasty (PK). Methods: This pilot study included five eyes of five patients with a mean spherical equivalent of −5.1 ± 1.46 D (range from −2.75 to −6.50 D). In all cases, ametropia and irregular astigmatism was corrected with topography-guided customized PRK. Ocular examinations with topographic analysis were perfor...

Indicações para ceratoplastia penetrante no Hospital das Clínicas-UNICAMP Penetrating keratoplasty indications in "Hospital das Clínicas-UNICAMP"

Directory of Open Access Journals (Sweden)

Vanessa Gonçalves Crespi Flores

2007-06-01

Full Text Available OBJETIVO: Determinar as principais causas de indicação de transplante penetrante no Hospital das Clínicas-UNICAMP no período de janeiro de 1999 a dezembro de 2003. MÉTODOS: Estudo de série de casos, retrospectivo, não comparativo. Os autores revisaram os prontuários de 857 pacientes submetidos à ceratoplastia penetrante no Hospital das Clínicas-UNICAMP entre 1999-2003 e os classificaram em categorias diagnósticas de indicação para cirurgia. RESULTADOS: Dentre os 857 prontuários revisados a idade variou de 0-88 anos (média 44 anos±1,2. Dentre as principais causas de indicação de transplante de córnea encontramos: ceratocone em 427 casos (49,82%; úlcera de córnea infecciosa perfurada ou não, 152 casos (17,74%; falência de transplante prévio, 87 casos (10,15%; ceratopatia bolhosa, 72 casos (8,40%; distrofia de Fuchs, 59 casos (6,88%; seqüela de tracoma, 28 casos (3,27%; outras causas, 32 casos (3,74%. Entre as crianças até 10 anos a principal causa de indicação de transplante foram as úlceras infecciosas (77,78% e entre 11-50 anos o ceratocone foi a principal causa (71,65%. CONCLUSÕES: Este estudo foi composto por uma população jovem e as principais causas de indicação de transplante foram o ceratocone e os transplantes tectônicos.PURPOSE: To determine the main causes of penetrating keratoplasty indications at "Hospital das Clínicas-UNICAMP" (January, 1999 to December, 2003. METHODS: A non-comparative, retrospective series of case studies. The authors reviewed the files of 857 patients who underwent penetrating keratoplasty at "Hospital das Clínicas-UNICAMP" between 1999-2003 and classified them into different categories according to diagnostic indication for surgery. RESULTS: The age range was between 0-88 years (average 44 years ±1.2. The main causes of penetrating keratoplasty were: keratoconus in 427 cases (49.82%; 152 cases (17.74% of corneal ulceration (perforated or not; corneal graft failure in 87

Update on the Management of High-Risk Penetrating Keratoplasty.

Science.gov (United States)

Jabbehdari, Sayena; Rafii, Alireza Baradaran; Yazdanpanah, Ghasem; Hamrah, Pedram; Holland, Edward J; Djalilian, Ali R

2017-03-01

In this article, we review the indications and latest management of high-risk penetrating keratoplasty. Despite the immune-privilege status of the cornea, immune-mediated graft rejection still remains the leading cause of corneal graft failure. This is particularly a problem in the high-risk graft recipients, namely patients with previous graft failure due to rejection and those with inflamed and vascularized corneal beds. A number of strategies including both local and systemic immunosuppression are currently used to increase the success rate of high-risk corneal grafts. Moreover, in cases of limbal stem cell deficiency, limbal stem cells transplantation is employed. Corticosteroids are still the top medication for prevention and treatment in cases of corneal graft rejection. Single and combined administration of immunosuppressive agents e.g. tacrolimus, cyclosporine and mycophenolate are promising adjunctive therapies for prolonging graft survival. In the future, cellular and molecular therapies should allow us to achieve immunologic tolerance even in high-risk grafts.

Endothelial keratoplasty using donor tissue not suitable for full-thickness penetrating keratoplasty.

Science.gov (United States)

Armour, Rebecca L; Ousley, Paula J; Wall, Jennifer; Hoar, Karen; Stoeger, Chris; Terry, Mark A

2007-06-01

To evaluate the use of corneal donor tissue deemed unsuitable for full-thickness penetrating keratoplasty (PK) for use in deep lamellar endothelial keratoplasty (DLEK) and to compare postoperative results to those of DLEK surgery using donor tissue that is suitable for PK. Small-incision DLEK surgery was performed using 39 donor corneas unsuitable for PK. Thirty-five donors had anterior scars or opacities, 3 donors had pterygia within the 8-mm zone, and 1 had prior LASIK. All donor preparation was completed by manual stromal dissection. The DLEK surgical and postoperative courses were reviewed. Preoperative and 6-month postoperative results of this study group were compared with a control group consisting of the first 55 consecutive small-incision DLEK patients receiving donor corneas that had no criteria excluding them from use in PK. Four eyes in the study group and 1 eye in the control group had the confounding variables of the presence of an anterior-chamber lens or surgical vitrectomy with macular disease in the recipient eye. There was no significant difference in preoperative measurements of best spectacle-corrected visual acuity (BSCVA; P = 0.372), donor endothelial cell density (ECD; P = 0.749), or corneal topography [surface regularity index (SRI), P = 0.485; or surface asymmetry index (SAI), P = 0.154] between the 2 groups. For the patients receiving corneas deemed unacceptable for PK, at 6 months after surgery, the vision (P = 0.002) and corneal topography measurements improved significantly from before surgery (SRI, P < 0.001; SAI, P < 0.001), and there was no significant change in refractive astigmatism (P = 0.240). There was a significant difference in the vision at 6 months postoperatively between the overall study group and the control group, with the mean vision of the study group at 20/56 and the control group at 20/43 (P = 0.015). If eyes with known cystoid macular edema (CME) and vitrectomy are removed from each group, there is no significant

Ahmed glaucoma valve in post-penetrating-keratoplasty glaucoma: A critically evaluated prospective clinical study

Science.gov (United States)

Panda, Anita; Prakash, Vadivelu Jaya; Dada, Tanuj; Gupta, Anoop Kishore; Khokhar, Sudarshan; Vanathi, Murugesan

2011-01-01

Aim: The aim was to evaluate the outcome of Ahmed glaucoma valve (AGV) in post-penetrating-keratoplasty glaucoma (PKPG). Materials and Methods: In this prospective study, 20 eyes of 20 adult patients with post-PKPG with intraocular pressure (IOP) >21 mmHg, on two or more antiglaucoma medications, underwent AG (model FP7) implantation and were followed up for a minimum of 6 months. Absolute success was defined as 5 glaucoma managed by AGV implantation revealed a satisfactory outcome up to 6 months of follow-up. PMID:21586837

Combined keratoplasty and cataract extraction.

Science.gov (United States)

Demeler, U; Hinzpeter, E N

1977-04-01

A short film showing our technique of combined penetrating keratoplasty and intracapsular cataract extraction was shown, and the postoperative results in 72 eyes after an average of 3 years were reported.

Quantification of collagen ultrastructure after penetrating keratoplasty - implications for corneal biomechanics.

Directory of Open Access Journals (Sweden)

Craig Boote

Full Text Available To quantify long-term changes in stromal collagen ultrastructure following penetrating keratoplasty (PK, and evaluate their possible implications for corneal biomechanics.A pair of 16 mm post-mortem corneo-scleral buttons was obtained from a patient receiving bilateral penetrating keratoplasty 12 (left/28 (right years previously. Small-angle x-ray scattering quantified collagen fibril spacing, diameter and spatial order at 0.5 mm or 0.25 mm intervals along linear scans across the graft margin. Corresponding control data was collected from two corneo-scleral buttons with no history of refractive surgery. Wide-angle x-ray scattering quantified collagen fibril orientation at 0.25 mm (horizontal×0.25 mm (vertical intervals across both PK specimens. Quantification of orientation changes in the graft margin were verified by equivalent analysis of data from a 13 year post-operative right PK specimen obtained from a second patient in a previous study, and comparison made with new and published data from normal corneas.Marked changes to normal fibril alignment, in favour of tangentially oriented collagen, were observed around the entire graft margin in all PK specimens. The total number of meridional fibrils in the wound margin was observed to decrease by up to 40%, with the number of tangentially oriented fibrils increasing by up to 46%. As a result, in some locations the number of fibrils aligned parallel to the wound outnumbered those spanning it by up to five times. Localised increases in fibril spacing and diameter, with an accompanying reduction in matrix order, were also evident.Abnormal collagen fibril size and spatial order within the PK graft margin are indicative of incomplete stromal wound remodelling and the long term persistence of fibrotic scar tissue. Lasting changes in collagen fibril orientation in and around PK wounds may alter corneal biomechanics and compromise the integrity of the graft-host interface in the long term.

Novel method to avoid the open-sky condition in penetrating keratoplasty: covered cornea technique.

Science.gov (United States)

Arslan, Osman S; Unal, Mustafa; Arici, Ceyhun; Cicik, Erdoğan; Mangan, Serhat; Atalay, Eray

2014-09-01

The aim of this study was to present a novel technique to avoid the open-sky condition in pediatric and adult penetrating keratoplasty (PK). Seventy-two eyes of 65 infants and children and 44 eyes of 44 adult patients were operated on using this technique. After trephining the recipient cornea up to a depth of 50% to 70%, the anterior chamber was entered at 1 point. Then, only a 2 clock hour segment of the recipient button was incised, and this segment was sutured to the recipient rim with a single tight suture. The procedure was repeated until the entire recipient button was excised and resutured. The donor corneal button was sutured to the recipient corneal rim. The sutures between the recipient button and the rim were then cut off, and the recipient button was drawn out. None of the patients operated on with this technique developed complications related to the open-sky condition. Visual acuities, graft failure rates, and endothelial cell loss were comparable with the findings of studies performed for conventional PK. The technique described avoids the open-sky condition during the entire PK procedure. Endothelial cell loss rates are acceptable.

Indications for and techniques of keratoplasty at Vietnam National Institute of Ophthalmology

Directory of Open Access Journals (Sweden)

Pham Ngoc Dong

2016-03-01

Full Text Available AIM: To report the indications for and techniques of corneal transplantation at Vietnam National Institute of Ophthalmology (VNIO over a period of 12y (2002-2013. METHODS: Records of patients who had undergone corneal transplantation at VNIO from January 1, 2002 to January 1, 2014 were reviewed to determine the indication for and type of corneal transplant performed. Patient age, gender, indication for corneal transplantation and surgical technique were recorded and analyzed. RESULTS: Corneal transplantation were underwent in 1390 eyes of 1278 patients with a mean age of 44.9±18.1y during the period under review. The most common indication was infectious corneal ulcer (n=670; 48.2%, followed by corneal scar (n=333, 24.0%, corneal dystrophy (n=138, 9.9% and failed graft (n=112, 8.1%. Nearly all procedures performed were penetrating keratoplasty (n=1300, 93.5%, with a few lamellar keratoplasty procedures performed: lamellar keratoplasty (n=52, 3.7%, Descemet’s stripping automated endothelial keratoplasty (n=27, 1.9% and deep anterior lamellar keratoplasty (n=11, 0.8%. CONCLUSION: While the most common indication for keratoplasty was infectious keratitis, nearly all indications for corneal transplantation were managed with penetrating keratoplasty. However, lamellar keratoplasty techniques, including deep anterior lamellar keratoplasty and Descemet’s stripping automated endothelial keratoplasty, are being performed with increasing frequency for isolated stromal and endothelial disorders, respectively.

Evolution of endothelial keratoplasty.

Science.gov (United States)

Price, Francis W; Price, Marianne O

2013-11-01

Endothelial keratoplasty has evolved into a popular alternative to penetrating keratoplasty (PK) for the treatment of endothelial dysfunction. Although the earliest iterations were challenging and were not widely adopted, the iteration known as Descemet stripping endothelial keratoplasty (DSEK) has gained widespread acceptance. DSEK combines a simplified technique for stripping dysfunctional endothelium from the host cornea and microkeratome dissection of the donor tissue, a step now commonly completed in advance by eye bank technicians. Studies show that a newer endothelial keratoplasty iteration, known as Descemet membrane endothelial keratoplasty (DMEK), provides an even faster and better visual recovery than DSEK does. In addition, DMEK significantly reduces the risk of immunologic graft rejection episodes compared with that in DSEK or in PK. Although the DMEK donor tissue, consisting of the bare endothelium and Descemet membrane without any stroma, is more challenging to prepare and position in the recipient eye, recent improvements in instrumentation and surgical techniques are increasing the ease and the reliability of the procedure. DSEK successfully mitigates 2 of the main liabilities of PK: ocular surface complications and structural problems (including induced astigmatism and perpetually weak wounds), whereas DMEK further mitigates the 2 principal remaining liabilities of PK: immunologic graft reactions and secondary glaucoma from prolonged topical corticosteroid use.

Comparison of graft survival following penetrating keratoplasty and Descemet's stripping endothelial keratoplasty in eyes with a glaucoma drainage device.

Science.gov (United States)

Iverson, Shawn M; Spierer, Oriel; Papachristou, George C; Feuer, William J; Shi, Wei; Greenfield, David S; O'Brien, Terrence P

2018-02-01

To compare corneal graft survival rates after penetrating keratoplasty (PK) and Descemet's stripping endothelial keratoplasty (DSEK) in patients with a glaucoma drainage device (GDD) or medically managed glaucoma. A retrospective chart review was conducted on consecutive patients who underwent primary PK or primary DSEK. Inclusion criteria consisted of eyes with a diagnosis of glaucoma prior to corneal transplantation and a minimum of 6 months of follow-up. Graft failure was defined as an edematous cornea with failure to maintain deturgescence lasting beyond a period of 1 month of intense steroid therapy or vascularization and scarring resulting in irreversible loss of central graft clarity. Corneal graft survival was calculated using Kaplan-Meier survival analysis. Patients were divided into four groups: GDD-PK, GDD-DSEK, medical-PK and medical-DSEK. Fifty-six eyes of 56 patients were identified as meeting inclusion criteria. Among eyes with a GDD, there was no difference in the proportion of failures between PK grafts (48%) and DSEK grafts (50%) (p = 0.90). Failure occurred earlier in DSEK recipients compared to PK recipients, 5.82 ± 6.77 months versus 14.40 ± 7.70 months, respectively (p = 0.04). A Kaplan-Meier analysis did not identify a difference between the four groups with respect to graft failure (p = 0.52). There is no significant difference in graft survival rates between medically and surgically treated glaucoma patients for either PK or DSEK grafts. In patients with GDD, graft failure occurs earlier in DSEK compared to PK.

Quantification of Collagen Ultrastructure after Penetrating Keratoplasty – Implications for Corneal Biomechanics

Science.gov (United States)

Gardner, Steven J.; Kamma-Lorger, Christina S.; Hayes, Sally; Nielsen, Kim; Hjortdal, Jesper; Sorensen, Thomas; Terrill, Nicholas J.; Meek, Keith M.

2013-01-01

Purpose To quantify long-term changes in stromal collagen ultrastructure following penetrating keratoplasty (PK), and evaluate their possible implications for corneal biomechanics. Methods A pair of 16 mm post-mortem corneo-scleral buttons was obtained from a patient receiving bilateral penetrating keratoplasty 12 (left)/28 (right) years previously. Small-angle x-ray scattering quantified collagen fibril spacing, diameter and spatial order at 0.5 mm or 0.25 mm intervals along linear scans across the graft margin. Corresponding control data was collected from two corneo-scleral buttons with no history of refractive surgery. Wide-angle x-ray scattering quantified collagen fibril orientation at 0.25 mm (horizontal)×0.25 mm (vertical) intervals across both PK specimens. Quantification of orientation changes in the graft margin were verified by equivalent analysis of data from a 13 year post-operative right PK specimen obtained from a second patient in a previous study, and comparison made with new and published data from normal corneas. Results Marked changes to normal fibril alignment, in favour of tangentially oriented collagen, were observed around the entire graft margin in all PK specimens. The total number of meridional fibrils in the wound margin was observed to decrease by up to 40%, with the number of tangentially oriented fibrils increasing by up to 46%. As a result, in some locations the number of fibrils aligned parallel to the wound outnumbered those spanning it by up to five times. Localised increases in fibril spacing and diameter, with an accompanying reduction in matrix order, were also evident. Conclusions Abnormal collagen fibril size and spatial order within the PK graft margin are indicative of incomplete stromal wound remodelling and the long term persistence of fibrotic scar tissue. Lasting changes in collagen fibril orientation in and around PK wounds may alter corneal biomechanics and compromise the integrity of the graft-host interface in the

Descemet Stripping Automated Endothelial Keratoplasty for Failed Penetrating Keratoplasty: Influence of the Graft-Host Junction on the Graft Survival Rate.

Science.gov (United States)

Omoto, Takashi; Sakisaka, Toshihiro; Toyono, Tetsuya; Yoshida, Junko; Shirakawa, Rika; Miyai, Takashi; Yamagami, Satoru; Usui, Tomohiko

2018-04-01

To investigate the clinical results of Descemet stripping automated endothelial keratoplasty (DSAEK) for failed penetrating keratoplasty (PK) and the influence of the graft-host junction (GHJ) on the graft survival rate. Data were retrospectively collected on patient demographics, visual outcomes, complications, and graft survival rate for 17 eyes of 16 patients who underwent DSAEK for failed PK. The graft survival rate was compared between the eyes when divided into a bump group and a well-aligned group according to the shape of the GHJ detected on anterior segment optical coherence tomography. The most common indication for initial PK was bullous keratopathy after glaucoma surgery (35.3%). Seven eyes (41.2%) were classified into the bump group and 10 eyes (58.8%) into the well-aligned group. The mean best-ever documented visual acuity (BDVA) after DSAEK was 0.33 logMAR. Postoperatively, almost 70% of eyes achieved a BDVA that was within 0.2 logMAR of their preoperative BDVA. Graft detachment occurred in 29.4% of eyes and primary graft failure in 17.6%. All primary failures occurred in the bump group. The cumulative graft survival rate was 82.3% at 1 year, 73.2% at 2 years, and 58.6% at 3 years. Graft failure was more likely in eyes in the bump group than in those in the well-aligned group (P = 0.037, Wilcoxon test). DSAEK for failed PK had a favorable outcome in this study. However, the GHJ should be assessed carefully before performing the procedure.

Quantitative & qualitative analysis of endothelial cells of donor cornea before & after penetrating keratoplasty in different pathological conditions

Directory of Open Access Journals (Sweden)

Aruna K.R. Gupta

2016-01-01

Full Text Available Background & objectives: Endothelial cells of the donor cornea are known to be affected quantitatively and qualitatively in different pathological conditions after penetrating keratoplasty (PK and this has direct effect on the clarity of vision obtained after PK. This study was undertaken to analyze the qualitative and quantitative changes in donor endothelial cells before and after PK in different pathological conditions. Methods: A prospective investigational analysis of 100 consecutive donor corneas used for penetrating keratoplasty between June 2006 and June 2008, was conducted. The patients were evaluated on the first day, at the end of first week, first month, third and six months and one year. Results: A decrease was observed in endothelial cell count in all pathological conditions. After one year of follow up the loss was 33.1 per cent in corneal opacity, 45.9 per cent in acute infective keratitis (AIK, 58.5 per cent in regrafts, 28.5 per cent in pseudophakic bullous keratopathy (PBK, 37 per cent in descemetocele, 27 per cent in keratoconus and 35.5 per cent in aphakic bullous keratopathy (ABK cases. Interpretation & conclusions: The endothelial cell loss was highest in regraft cases which was significant (P<0.05, while the least endothelial cell loss was seen in keratoconus cases. The cell loss was associated with increase in coefficient of variation (CV, i.e. polymegathism and pleomorphism. Inspite of this polymegathism and pleomorphism, the clarity of the graft was maintained.

A case of recipient bed melt and wound dehiscence after penetrating keratoplasty and subconjunctival injection of bevacizumab.

Science.gov (United States)

Bhasin, Purendra; Gujar, Prateek; Bhasin, Priyamvada

2012-11-01

We describe a case of recipient bed melt and wound dehiscence after uneventful penetrating keratoplasty and subconjunctival injection of bevacizumab. Three weeks postoperatively, the patient presented with limbal ischemia, recipient bed melt, and wound dehiscence corresponding to the area of bevacizumab injection. The melt was managed by application of cyanoacrylate glue along with bandage contact lens. Although the graft survived, there was a problem in re-epithelization. This case highlights the need for further studies to elucidate the therapeutic dose, side effects, and correct timing of using bevacizumab with respect to corneal transplant surgery.

Clinical outcomes of trabeculectomy vs. Ahmed glaucoma valve implantation in patients with penetrating keratoplasty : (Trabeculectomy vs. Ahmed galucoma valve in patients with penetrating keratoplasty).

Science.gov (United States)

Akdemir, Mehmet Orcun; Acar, Banu Torun; Kokturk, Furuzan; Acar, Suphi

2016-08-01

The aim of this study was to compare the visual outcomes, intraocular pressure (IOP), and endothelial cell loss caused by trabeculectomy (TRAB) and Ahmed glaucoma valve (AGV) implantation in patients who had previously undergone penetrating keratoplasty (PKP). The data from all patients who underwent surgical treatment of glaucoma after PKP were reviewed at the Cornea Department of Haydarpasa Numune Education and Research Hospital. Eighteen patients who had undergone surgical treatment of glaucoma after PKP were included in this retrospective study. Time between PKP and glaucoma surgeries, visual acuity results, IOP results, endothelial cell counts (ECC) before the surgery, at 1st, 6th, and 12th month of surgery were recorded. Differences between two groups were evaluated. Mean loss of ECC was 315 cells/mm(2) in the AGV group and 197 cells/mm(2) in TRAB group at 12th month of glaucoma surgery. The difference between endothelial cell loss at 12th month of surgery was statistically significant and higher in AGV group (p glaucoma. Ahmed glaucoma valve had a significantly better IOP lowering but higher endothelial cell loss effect.

The treatment of acute corneal hydrops by subtotal penetrating keratoplasty. Clinical case

Directory of Open Access Journals (Sweden)

I. A. Loskutov

2014-07-01

Full Text Available Clinical case of acute hydrops treatment using subtotal penetrating keratoplasty (PK is presented. The diagnosis of acute hydrops was based on clinical and functional evaluations including optical coherent tomography (OCT. A part of diseased cornea was removed and examined under a light microscope. These studies revealed morphological changes in almost all corneal layers. OCT and histology demonstrated that PK was indicated to this patient. Recent literature data on the epidemiology and pathogenesis of acute hydrops are presented. This rare disease results from tears in the Descemet’s membrane that allow aqueous humor to enter the stroma. Current treatment is aimed to suppress corneal inflammation, restore endothelium and Descemet’s membrane integrity and drain stromal cysts to optimize cornea healing. In this case, subtotal PK was performed due to the significant corneal thinning and a high risk of its melting. «Material for corneal graft» (iLab, Moscow, Russia was used as a donor material.

Laser welding in penetrating keratoplasty and cataract surgery of pediatric patients: early results

Science.gov (United States)

Rossi, Francesca; Pini, Roberto; Menabuoni, Luca; Malandrini, Alex; Canovetti, Annalisa; Lenzetti, Ivo; Capozzi, Paolo; Valente, Paola; Buzzonetti, Luca

2013-03-01

Diode laser welding of ocular tissues is a procedure that enables minimally invasive closure of a corneal wound. This procedure is based on a photothermal effect: a water solution of Indocyanine Green (ICG) is inserted in the surgical wound, in order to stain the corneal tissue walls. The stained tissue is then irradiated with a low power infrared diode laser, delivering laser light through a 300-μm core diameter optical fiber. This procedure enables an immediate closure of the wounds: it is thus possible to reduce or to substitute the use of surgical threads. This is of particular interest in children, because the immediate closure improves refractive outcome and anti-amblyopic effect; moreover this procedure avoids several general anaesthesia for suture management. In this work, we present the first use of diode laser welding procedure in paediatric patients. 5 selected patients underwent cataract surgery (Group 1), while 4 underwent fs-laserassisted penetrating keratoplasty (Group 2). In Group 1 the conventional surgery procedure was performed, while no stitches were used for the closure of the surgical wounds: these were laser welded and immediately closed. In Group 2 the donor button was sutured upon the recipient by 8 single stitches, instead of 16 single stitches or a running suture. The laser welding procedure was performed in order to join the donor tissue to the recipient bed. Objective observations in the follow up study evidenced a perfect adhesion of the laser welded tissues, no collateral effects and an optimal restoration of the treated tissues.

Indications of Optical Coherence Tomography in Keratoplasties: Literature Review

Directory of Open Access Journals (Sweden)

Thiago Trindade Nesi

2012-01-01

Full Text Available Optical coherence tomography (OCT of the anterior segment, in particular corneal OCT, has become a reliable tool for the cornea specialist, as it provides the acquisition of digital images at high resolution with a noncontact technology. In penetrating or lamellar keratoplasties, OCT can be used to assess central corneal thickness and pachymetry maps, as well as precise measurements of deep stromal opacities, thereby guiding the surgeon to choose the best treatment option. OCT has also been used to evaluate the keratoplasty postoperative period, for early identification of possible complications, such as secondary glaucoma or donor disc detachments in endothelial keratoplasties. Intraoperatively, OCT can be used to assess stromal bed regularity and transparency in anterior lamellar surgeries, especially for those techniques in which a bare Descemet’s membrane is the goal. The purpose of this paper is to review and discuss the role of OCT as a diagnostic tool in various types of keratoplasties.

Femtosecond laser-assisted keratoplasty in a child with corneal opacity:case report

Directory of Open Access Journals (Sweden)

E. Yu. Markova

2014-01-01

Full Text Available Corneal opacities are the fourth cause of blindness world-wide. Over the past two centuries, various corneal transplantation (i.e., keratoplasty methods have been developed and improved. Nowadays, femtolaserssisted keratoplasty is one of most promising techniques. Femtosecond laser have several advantages that provide additional surgical benefits. Among them, no thermal injury, the ability to cut deeply on a single plane and to perform various corneal profiles should be mentioned. In children, corneal disorders are of special importance while femtosecondassisted keraatoplasty case reports are rare. Here, we describe femtosecond laserssisted penetrating keratoplasty in a girl with a rough central corneal opacity.

Photorefractive keratectomy for post-penetrating keratoplasty myopia and astigmatism.

Science.gov (United States)

Bilgihan, K; Ozdek, S C; Akata, F; Hasanreisoğlu, B

2000-11-01

To determine the safety, effectiveness, and predictability of photorefractive keratectomy (PRK) for the correction of myopia and astigmatism after penetrating keratoplasty. Gazi University, Medical School, Department of Ophthalmology, Ankara, Turkey. Photorefractive keratectomy was performed in 16 eyes of 16 patients with postkeratoplasty myopia and astigmatism who were unable to wear glasses due to anisometropia and were contact lens intolerant. They were examined for uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and corneal transplant integrity before and after surgery. The mean follow-up after PRK was 26.0 months +/- 15.7 (SD) (range 12 to 63 months). The mean preoperative spherical equivalent refraction of -4.47 +/- 1.39 diopters (D) was -3.39 +/- 1.84 D (P >.05) at the last postoperative visit and the mean preoperative cylinder of -5.62 +/- 2.88 D was -3.23 +/- 1.70 D (P <.05); refractive regression correlated with the amount of ablation performed. The BSCVA decreased in 3 eyes (18.8%), and the UCVA decreased in 2 (12.5%). Six eyes (37.5%) had grade 2 to 3 haze, which resolved spontaneously in 4 eyes within a relatively long time but caused a decrease in BSCVA in 2 (12.5%). Two of the eyes (12.5%) had a rejection episode after PRK and were successfully treated with topical steroids. Photorefractive keratectomy to correct postkeratoplasty myopia and astigmatism appears to be less effective and less predictable than PRK for naturally occurring myopia and astigmatism. Corneal haze and refractive regression are more prevalent, and patient satisfaction is not good.

Fuchs' dystrophy associated with radial keratotomy: Lamellar or perforating keratoplasty?

Science.gov (United States)

Rodriguez-Ausin, P; Antolin-Garcia, D; Santamaria Garcia, L; Blazquez-Fernandez, A-B

2017-05-01

A 70 year-old male patient with a history of radial keratotomy suffering from Fuchs' dystrophy and a cataract. The patient received a two-step surgery: lens phacoemulsification and intraocular lens implant, followed by descemet stripping automated endothelial keratoplasty in both eyes, four months later. There were no complications apart from a recurrent cystoid macular oedema in both eyes. The best corrected visual acuity was 20/40 both eyes, and the patient was satisfied. Descemet stripping automated endothelial keratoplasty may be considered as an alternative to penetrating keratoplasty in the case of endothelial dysfunction and radial keratotomy in patients with no corneal ectasia or significant stromal opacity. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

Excimer laser-assisted anterior lamellar keratoplasty for keratoconus, corneal problems after laser in situ keratomileusis, and corneal stromal opacities.

Science.gov (United States)

Bilgihan, Kamil; Ozdek, Sengül C; Sari, Ayça; Hasanreisoğlu, Berati

2006-08-01

To evaluate excimer laser-assisted anterior lamellar keratoplasty to augment thin corneas as in keratoconus ( .05). This technique presents a different modality for the treatment of keratoconus, post-LASIK corneal problems, and other corneal stromal opacities with anterior lamellar keratoplasty. Additional studies with more patients and longer follow-up will help determine the role of this technique as a substitute for penetrating keratoplasty in these patients.

Estudo retrospectivo dos transplantes penetrantes de córnea da Santa Casa de Porto Alegre Retrospective study of penetrating keratoplasty at the Santa Casa of Porto Alegre

Directory of Open Access Journals (Sweden)

Caroline Fabris

2001-10-01

Full Text Available Objetivos: Traçar o perfil clínico e social dos pacientes submetidos a transplante de córnea e avaliar as principais indicações desses transplantes, tempo de espera para doação e os índices de sucesso, rejeição e falência dos transplantes penetrantes de córnea. Métodos: Foram analisados retrospectivamente os prontuários de 87 pacientes submetidos a transplante penetrante de córnea no Serviço de Oftalmologia da Santa Casa de Porto Alegre entre janeiro de 1990 e dezembro de 1998, totalizando 91 olhos. Destes, 56 pacientes foram chamados para avaliação clínica do enxerto durante o levantamento de dados para este estudo. Resultados: Considerando-se os 91 transplantes (87 pacientes, 53 (60,9% foram realizados em pacientes do sexo masculino e 34 (39%, do sexo feminino. A idade variou de 3 a 89 anos, com média de 42,3 ± 19,8 anos. As principais indicações para transplante de córnea foram ceratocone em 32 (35% olhos, ceratopatia bolhosa (pós-facectomia, distrofia de Fuchs e outros em 24 (26,4%, trauma mecânico em 9 (9,9%, causas infecciosas em 9 (9,9%, queimadura química em 2 (2,2%, queimadura térmica em 1 (1,1% e outras causas em 14 (15,4% olhos. O tempo médio de espera por doação de córnea foi de 17,3 ± 9,9 meses. Do total de 91 olhos transplantados, 25 (27,5% apresentaram rejeição e 12 (13,2% olhos apresentaram falência do transplante. Conclusões: Este estudo mostrou a epidemiologia dos pacientes transplantados. A falta de dados seriados devido à alta precoce e perda de acompanhamento dos pacientes tornou impossível a análise e a comparação dos resultados pós-operatórios com outros estudos.Purpose: To describe the clinical and social profile of recipient patients of transplanted corneas, and to evaluate main indications for corneal transplants, waiting time for donor tissue, and percentages of success, rejection and failure of penetrating keratoplasty. Methods: Retrospective chart review of 87 patients

Resultados e indicações de ceratoplastias penetrantes realizadas por médicos em treinamento, num país em desenvolvimento Indications and results of penetrating keratoplasty performed by training physicians in a developing country

Directory of Open Access Journals (Sweden)

Marta Ferrari Teixeira

2001-11-01

Full Text Available Objetivos: Avaliar as indicações mais freqüentes, bem como o resultado da acuidade visual final após a ceratoplastia penetrante, realizadas por residentes em treinamento. Métodos: Avaliaram-se retrospectivamente 159 casos de ceratoplastia penetrante realizadas no período de janeiro de 1991 a outubro de 1998, na Faculdade de Medicina de São José do Rio Preto - Hospital de Base, correlacionando-os em termos de indicação para ceratoplastia penetrante e acuidade visual final. O tempo mínimo de acompanhamento para obtenção da acuidade visual final foi de seis meses. Para comparação e análise estatística da acuidade visual final, os casos de ceratoplastia penetrante foram divididos em seis grupos de diagnóstico pré-operatório: ceratocone, ceratopatia bolhosa pseudofácica, ceratopatia bolhosa afácica, distrofia endotelial de Fuchs, ceratopatia em faixa e leucomas. Todas as cirurgias foram realizadas por residentes em treinamento, sob supervisão docente. Resultados: O ceratocone foi o grupo que atingiu um maior aumento médio de acuidade visual pós-operatória em linhas (7,55 ± 2,83 e a ceratopatia em faixa o menor (0,33 ± 3,20. Constatou-se significativa diferença entre as indicações encontradas nos países desenvolvidos, onde se observa predominância de ceratocone. De acordo com nosso estudo, as principais indicações para ceratoplastia penetrante foram, em ordem decrescente, leucoma, ceratopatia bolhosa pseudofácica, ceratocone, distrofia endotelial de Fuchs, ceratopatia bolhosa afácica e ceratopatia em faixa. Conclusão: O ceratocone apresentou diferença significativa (p Purpose: This study was designed to evaluate the most frequent indications, as well as the results of final visual acuity (VA after penetrating keratoplasty (PK, performed by residents. Methods: A consecutive series of 159 cases of PK was followed during the period from January 1991 to October 1998, at the Medical School of São Jose do Rio Preto

Indications and outcomes of pediatric keratoplasty in a tertiary eye care center: A retrospective review.

Science.gov (United States)

Gulias-Cañizo, Rosario; Gonzalez-Salinas, Roberto; Hernandez-Zimbron, Luis Fernando; Hernandez-Quintela, Everardo; Sanchez-Huerta, Valeria

2017-11-01

To evaluate indications and outcomes of pediatric keratoplasty in a tertiary eye center, and identify factors that affect visual outcomes.We performed a retrospective review of penetrating keratoplasty in children aged 0 to 18 years between 1995 and 2011 in the Asociación para Evitar la Ceguera en México IAP, Hospital "Dr. Luis Sánchez Bulnes".A total of 574 penetrating keratoplasties were performed during the study interval. Median follow-up was 5.0 years. Main indications included keratoconus (55.58%), postherpetic scarring (9.58%), traumatic opacities (7.49%), and bullous keratopathy (6.09%). Rejection rates at 5 years were 27% overall, and among indications, keratoconus showed the best graft survival at 60-months follow-up (85%). The percentage of patients with best corrected visual acuity (BCVA) posttransplant >20/400 at 5 years in the nonrejection group was 81.25% and 82.74% in 10 years of age (YOA) groups, respectively, versus a BCVA posttransplant > 20/400 at 5 years in the rejection group of 53.68% and 51.72% in 10 YOA groups, respectively. There was a statistically significant reduced rejection rate between genders at 18 months of follow-up, favoring males.Despite being considered a high-risk procedure in children, penetrating keratoplasty can achieve good results, especially in patients with keratoconus. It can achieve significative improvements of visual acuity, provided there is an adequate follow-up and treatment adherence.

Penetrating keratoplasty in eThekwini Health District 2011–2014

Directory of Open Access Journals (Sweden)

Monawwar Khan

2015-07-01

Full Text Available Background: Penetrating keratoplasty (PK – corneal transplantation or full-thickness corneal graft remains the primary sight-restoring procedure for corneal blindness. South Africa is experiencing a shortage of donor corneas, resulting in long waiting times for a corneal transplant. A corneal graft protocol has been drawn up in the eThekwini Health District to triage prospective corneal graft recipients. Aim: To describe the clinical and demographic profiles of patients on the elective corneal graft waiting list, the waiting time for PK and the scoring system prioritisation process of corneal graft allocation. Setting: All patients on the elective corneal graft waiting list in the eThekwini Health District. Methods: An observational, descriptive cross-sectional study was conducted for a 3-year period between April 2011 and March 2014. Results: A total of 104 patients were on the elective corneal graft waiting list for PK during the study period. Only 20% (n = 21 of patients received a corneal graft during the 3-year period. Amongst those that received a corneal graft, the median waiting period was 280 days (interquartile range 143–520 days. The majority of patients on the waiting list (67% were younger than 41 years of age. The commonest indication for PK was keratoconus (64%. Patients with higher pro forma scores are more likely to receive a corneal graft when a donor cornea becomes available. Conclusion: With a shortage of donor corneas, very few patients receive a corneal graft. Educational programmes are vital to increase awareness of corneal blindness and the value of corneal donations.

Comparison the post operative refractive errors in same size corneal transplantation through deep lamellar keratoplasty and penetrating keratoplasty methods after sutures removing in keratoconus patients

Directory of Open Access Journals (Sweden)

Hasan Razmjoo

2016-01-01

Full Text Available Background: Corneal transplantation is a surgery in which cornea is replaced by a donated one and can be completely penetrating keratoplasty (PK or included a part of cornea deep lamellar keratoplasty (DLK. Although the functional results are limited by some complications, it is considered as one of the most successful surgeries. This study aimed to compare the refractive errors after same size corneal transplantation through DLK and PK methods in keratoconus patients over 20 years. Materials and Methods: This descriptive, analytical study was conducted in Feiz Hospital, Sadra and Persian Clinics of Isfahan in 2013–2014. In this study, 35 patients underwent corneal transplantation by PK and 35 patients by DLK, after removing the sutures, the patients were compared in terms of best corrected visual acuity (BCVA and refractive errors. Data were analyzed using Chi-square and t Student tests by SPSS software. Results: The BCVA mean in DLK and PK groups was 6/10 ± 2/10 and 5/10 ± 2/10, respectively, with no significant difference (P = 0.4. The results showed 9 cases of DLK and 6 cases of PK had normal (8/10 ≤ BCVA visual acuity (25.7% vs. 17.1%, 24 cases of DLK and 27 cases of PK had mild vision impairment (68.6% vs. 77.1% and 2 cases of the DLK group and 2 cases of PK had moderate vision impairment, (5.7% vs. 5.7%, there was no significant difference in “BCVA” (P = 0.83. Conclusions: Both methods were acceptably effective in improving BCVA, but according to previous articles (5,9,10 the DLK method due to fewer complications and less risk of rejection was superior to another method and in the absence of any prohibition this method is recommended.

Development of a nomogram for femtosecond laser astigmatic keratotomy for astigmatism after keratoplasty.

Science.gov (United States)

St Clair, Ryan M; Sharma, Anushree; Huang, David; Yu, Fei; Goldich, Yakov; Rootman, David; Yoo, Sonia; Cabot, Florence; Jun, Jason; Zhang, Lijun; Aldave, Anthony J

2016-04-01

To develop a nomogram for femtosecond laser astigmatic keratotomy (AK) to treat post-keratoplasty astigmatism. Three academic medical centers. Retrospective interventional case series. A review of post-keratoplasty femtosecond laser AK was performed. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction, and keratometry were recorded preoperatively and 1, 3, 6, and 12 months postoperatively. The location, length, depth, and diameter of the AK incisions were recorded, and the surgically induced astigmatic correction was related to these variables using regression analysis. One hundred forty femtosecond laser AK procedures were performed after penetrating keratoplasty (PKP) (n = 129) or deep anterior lamellar keratoplasty (DALK) (n =11), with 89 procedures (80 PKP, 9 DALK) included in the analysis. The mean CDVA improved from 20/59 (0.47 logMAR ± 0.38 [SD]) preoperatively to 20/45 (0.35 ± 0.31 logMAR) postoperatively (P = .013) (n = 46). The mean keratometric astigmatism decreased from 8.26 ± 2.90 diopters (D) preoperatively to 3.62 ± 2.59 D postoperatively (P AK to treat post-keratoplasty astigmatism was generated using regression analysis. Femtosecond laser AK significantly improved UDVA and CDVA and significantly reduced keratometric astigmatism and refractive cylinder after keratoplasty. The nomogram generated should improve the accuracy of post-keratoplasty femtosecond laser AK. None of the authors has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Endoscopy-guided vitreoretinal surgery following penetrating corneal injury: a case report

Directory of Open Access Journals (Sweden)

Motoko Kawashima

2010-08-01

Full Text Available Motoko Kawashima1, Shinichi Kawashima2, Murat Dogru1,3, Makoto Inoue4, Jun Shimazaki1,51Department of Ophthalmology, Tokyo Dental College, Chiba, Japan; 2Department of Ophthalmology, International University of Health and Welfare, Tokyo, Japan; 3Department of Ocular Surface and Visual Optics, Keio University School of Medicine, Tokyo, Japan; 4Kyorin Eye Center, Tokyo, Japan; 5Department of Ophthalmology, Keio University School of Medicine, Tokyo, JapanIntroduction: Severe ocular trauma requires emergency surgery, and a fresh corneal graft may not always be available. We describe a case of perforating eye injury with corneal ­opacity, suspected endophthalmitis, and an intraocular foreign body. The patient was successfully treated with a two-step procedure comprising endoscopy-guided vitrectomy followed by corneal transplantation. This surgical technique offers a good option to vitrectomy with simultaneous keratoplasty in emergency cases where no graft is immediately available and there is the ­possibility of infection due to the presence of a foreign body.Case presentation: A 55-year-old Japanese woman was referred to our hospital with a ­perforating corneal and lens injury sustained with a muddy ferrous rod. Primary corneal sutures and lensectomy were performed immediately. Vitreoretinal surgery was required due to ­suspected endophthalmitis, vitreous hemorrhage, retinal detachment, dialysis and necrosis of the peripheral retina. Instead of conventional vitrectomy, endoscopy-guided vitreous surgery was performed with the Solid Fiber Catheter AS-611 (FiberTech, Tokyo, Japan due to the presence of corneal opacity and the unavailability of a donor cornea. The retina was successfully attached with the aid of a silicon oil tamponade. Following removal of the silicon oil at 3 months after surgery, penetrating keratoplasty and intraocular lens implantation with ciliary sulcus suture fixation were performed. At 6 months after penetrating

Correction of High Astigmatism after Penetrating Keratoplasty with Toric Multifocal Intraocular Lens Implantation

Directory of Open Access Journals (Sweden)

Raffaele Nuzzi

2017-07-01

Full Text Available After penetrating keratoplasty (PK, high astigmatism is often induced, being frequently about 4–6 dpt. According to the entity and typology of astigmatism, different methods of correction can be used. Selective suture removal, relaxing incisions, wedge resections, compression sutures, photorefractive keratectomy, and laser-assisted in situ keratomileusis can reduce corneal astigmatism and ametropia, but meanwhile they can cause a reduction in the corneal integrity and cause an over- or undercorrection. In case of moderate-to-high regular astigmatisms, the authors propose a toric multifocal intraocular lens (IOL implantation to preserve the corneal integrity (especially in PK after herpetic corneal leukoma keratitis. We evaluated a 45-year-old patient who at the age of 30 was subjected to PK in his left eye due to corneal leukoma herpetic keratitis, which led to high astigmatism (7.50 dpt cyl. 5°. The patient was subjected to phacoemulsification and customized toric multifocal IOL implantation in his left eye. The correction of PK-induced residual astigmatism with a toric IOL implantation is an excellent choice but has to be evaluated in relation to patient age, corneal integrity, longevity graft, and surgical risk. It seems to be a well-tolerated therapeutic choice and with good results.

Ahmed glaucoma valve in post-penetrating-keratoplasty glaucoma: A critically evaluated prospective clinical study

Directory of Open Access Journals (Sweden)

Anita Panda

2011-01-01

Full Text Available Aim: The aim was to evaluate the outcome of Ahmed glaucoma valve (AGV in post-penetrating-keratoplasty glaucoma (PKPG. Materials and Methods: In this prospective study, 20 eyes of 20 adult patients with post-PKPG with intraocular pressure (IOP >21 mmHg, on two or more antiglaucoma medications, underwent AG (model FP7 implantation and were followed up for a minimum of 6 months. Absolute success was defined as 5 < IOP < 21 mmHg and qualified success as 5 < IOP < 21 mmHg with medications or minor procedures. Results: The mean IOP decreased from 42.95 ± 10.24 to 17.69 ± 3.64 mmHg (P < 0.001 and the use of medications dropped from 2.92 to 0.39 (P < 0.001 after AGV implantation. The absolute success was achieved in 11 eyes and qualified success in 9. There was no significant change in best corrected visual acuity, graft clarity, or graft thickness. Six device-related complications occurred after AGV implantations which were successfully managed with medical or minor surgical therapy. Conclusions: Postkeratoplasty refractory glaucoma managed by AGV implantation revealed a satisfactory outcome up to 6 months of follow-up.

Microscopia confocal en operados de queratoplastia perforante Confocal microscopy in patients operated from penetrating keratoplasty

Directory of Open Access Journals (Sweden)

Zulema Gómez Castillo

2009-06-01

the characteristics of the corneal tissue in patients undergoing this type of transplantation through in vivo confocal microscopy. METHODS: A cross-sectional descriptive study was carried out in 40 eyes from 40 patients operated with penetrating keratoplasty in the Corneal Service of "Ramón Pando Ferrer" Cuban Institute of Ophthalmology from March 2006 to March 2007. A clinical ophthalmologic history was drafted, and they were all subjected to confocal microscopic examination of the corneal graft using confocal microscope CONFOSCAN 4. RESULTS: Pseuphakic bullosa keratopathy was the most common disease prior to surgery and was present in 77.5 % of patients. Corneal thickness decreased in 72.5 % of the operated patients. The epithelium was altered in 62.5 %. All of them presented with problems in the endotelial cellular form and size. Nervous plexuses were not observed in 82.5 % of patients. CONCLUSIONS: Confocal microscopy as a new science in the field of ophthalmology favors the follow-up of penetrating keratoplasty and allows preventing possible complications and assuring the success of surgery and the restoration of the refractive function of the cornea.

A case of acute postoperative keratitis after deep anterior lamellar keratoplasty by multidrug resistant Klebsiella

Directory of Open Access Journals (Sweden)

Leena Bajracharya

2015-01-01

Full Text Available A healthy lady of 42 years underwent deep anterior lamellar keratoplasty for granular dystrophy. The very next day, it was complicated by development of infectious keratitis. The organism was identified as multidrug resistant Klebsiella pneumoniae. Donor corneal button may be implicated in the transmission of infection in an otherwise uneventful surgery and follow-up. Nosocomial infections are usually severe, rapidly progressive and difficult to treat. Finally, the lady had to undergo therapeutic penetrating keratoplasty for complete resolution of infection.

Intraocular lens opacification after Descemet's stripping automated endothelial keratoplasty

Directory of Open Access Journals (Sweden)

Meng-Sheng Lee

2017-01-01

Full Text Available Compared with conventional penetrating keratoplasty, Descemet's stripping automated endothelial keratoplasty (DSAEK more effectively maintain global integrity and rapid vision rehabilitation with less ocular surface disorders in patients with endothelial dysfunction. Here, we report a case of a 76-year-old woman who experienced opacification of a hydrophilic intraocular lens (IOL approximately 10 months after DSAEK. The patient with no history of systemic disease developed pseudophakic bullous keratopathy in the right eye 2 years after undergoing cataract surgery. The best-corrected visual acuity (BCVA of the right eye was Snellen 0.01 when presented to our hospital. DSAEK was arranged and performed smoothly. However, the graft detached over the upper part of the cornea on postoperative day 1. Thus, rebubbling was performed immediately. After the procedure, the graft was well attached, and the cornea became clear gradually. The BCVA returned to Snellen 0.6. However, progressive opacification over the anterior surface of the IOL was observed 10 months postoperatively. Vision deteriorated to 0.5 with various refractive errors during 2-year follow-up. IOL exchange may be considered if the vision is getting worse. IOL opacification may result from a direct contact between the IOL surface and exogenous air, particularly in a hydrophilic IOL, and can be a rare but significant complication after DSAEK. Clinicians planning to perform DSAEK should consider the composition of the IOL, the amount of intracameral air, duration of air filling, and high intraocular pressure.

Ocular penetration and pharmacokinetics of topical gatifloxacin 0.3% and moxifloxacin 0.5% ophthalmic solutions after keratoplasty.

Science.gov (United States)

Holland, Edward J; Lane, Stephen S; Kim, Terry; Raizman, Michael; Dunn, Steven

2008-04-01

To compare the corneal and aqueous penetration and pharmacokinetics of gatifloxacin 0.3% and moxifloxacin 0.5% ophthalmic solutions and their effect on corneal reepithelialization after penetrating keratoplasty. In this randomized, open-label, parallel-controlled study, corneal and aqueous penetration and the pharmacokinetic parameters of topically applied gatifloxacin 0.3% and moxifloxacin 0.5% (2 preoperative doses of 1 drop given 5 minutes apart) were estimated by using a sparse sampling method. Corneal and aqueous samples were collected 0.25, 0.5, 1, or 2 hours after the final dose. The concentration was determined by a high-performance liquid chromatography method. Stromal Cmax:MBC50 (maximum drug concentration in serum to 50% minimum bactericidal concentration) ratios for selected ocular pathogens were also assessed. Postoperative corneal reepithelialization at days 1, 3, and 7 was evaluated and compared between groups. The calculated pharmacokinetic parameters were higher with moxifloxacin 0.5% than with gatifloxacin 0.3%. The stromal Cmax was 48.5 versus 15.7 microg/g (P = 0.04), and the stromal AUC0-2 (area under the concentration-time curve from 0 to 2 hours) was 30.9 versus 13.6 mug.h/g (P 0.05), and the endothelial AUC0-2 was 43.9 versus 9.8 microg.h/g (P 0.05), and the aqueous AUC0-2 was 1.2 versus 0.4 microg.h/mL (P < 0.05). Stromal Cmax:MBC50 ratios were higher in the moxifloxacin 0.5% group for each pathogen tested. The corneal reepithelialization rates were comparable between groups. Topical preoperative moxifloxacin 0.5% achieved greater corneal and aqueous penetration than did gatifloxacin 0.3%. The clinical significance of this difference is not known. Postoperative use of these agents had similar effects on corneal reepithelialization.

Management of Extreme Ametropia after Penetrating Keratoplasty: A Series of Surgical Procedures for High Myopia and Astigmatism

Directory of Open Access Journals (Sweden)

Jorge E. Valdez-Garcia

2014-08-01

Full Text Available A series of surgical interventions - relaxing corneal incisions, intraocular lens, and intrastromal rings - were used to correct a case of extreme ametropia in a thin cornea after a penetrating keratoplasty in an 18-year-old patient who presented with a -10.25 -8.50 × 120 preoperative refraction and 20/200 best-corrected visual acuity (BCVA. After a series of surgical procedures, the patient's BCVA in his left eye improved to 20/30 with +0.50 -1.00 × 170, the slit lamp examination showed no significant findings, and the patient's visual complaints disappeared. At the 1-year follow-up, the BCVA was 20/25, without visual complaints. The process of individualizing the surgical procedure in the present case was employed in an outcome-based approach, that is, the next surgical procedure was defined after the surgery and postoperative evaluation. The patient did not present complications during the follow-up period of 2.5 years.

[Management of corneal endothelial decompensation with Descemet's membrane endothelial keratoplasty in a patient with Ahmed glaucoma valve implant].

Science.gov (United States)

Röck, T; Bartz-Schmidt, K-U; Röck, D; Yoeruek, E

2014-05-01

Currently, the main causes for developing bullous keratopathy are from problems related to intraocular surgery, trauma, infection, Fuchs' endothelial dystrophy and chronically elevated intraocular pressure. In the 1990s penetrating keratoplasty was once considered the therapy of choice for treatment of bullous keratopathy but in recent years it has been replaced by posterior lamellar keratoplasty. The Descemet membrane endothelial keratoplasty (DMEK) procedure represents the final development of posterior lamellar keratoplasty. The question now arises whether DMEK can be used in patients with bullous keratopathy and Ahmed glaucoma valve implant. A 72-year-old man was referred to our hospital for further evaluation with the diagnosis of bullous keratopathy and pseudoexfoliative glaucoma. The bullous keratopathy was caused by a variety of previous operations as well as decompensation of intraocular pressure. This article describes the therapy of bullous keratopathy by DMEK with existing Ahmed glaucoma valve implant. After surgery the cornea became clear and the best-corrected visual acuity improved from hand movement to 0.2. The intraocular pressure remained normal (10-14 mmHg) without antiglaucoma medication and the endothelial cell count decreased only slightly over a follow-up of 13 months. No complications were encountered. The DMEK surgical procedure seems to be possible in patients with Ahmed glaucoma valve implant and endothelial decompensation. However, further studies with a larger number of patients should follow to validate the replacement of penetrating keratoplasty and other posterior lamellar procedures by DMEK.

Pre-banking microbial contamination of donor conjunctiva and storage medium for penetrating keratoplasty.

Science.gov (United States)

Inomata, Takenori; Ono, Koichi; Matsuba, Tsuyoshi; Shiang, Tina; Di Zazzo, Antonio; Nakatani, Satoru; Yamaguchi, Masahiro; Ebihara, Nobuyuki; Murakami, Akira

2017-09-01

The aims of this study were to investigate the incidence of positive donor tissue cultures before transfer to preservation medium (Optisol™-GS) for penetrating keratoplasty, to verify the efficacy of antibiotics contained in Optisol™-GS by examining the drug susceptibility and to assess the relationship between the results of our microbial assessments as well as donor factors and the incidence of contamination. We conducted a retrospective, cross-sectional study using Juntendo Eye Bank records for all corneal transplantations. Two hundred donor conjunctiva harvestings and storage medium (EP-II ® ) cultures were performed between July 2008 and June 2011. We analyzed the associations between donor factors (age, gender, history of cataract surgery, death-to-preservation interval, cause of death) and contamination rates using multivariate analysis by the generalized estimating equation model. We obtained positive bacterial cultures from 154 of the 200 eyes (77.0%). The isolated bacteria were indigenous, such as coagulase-negative Staphylococci, Corynebacterium sp., and methicillin-resistant Staphylococcus aureus (MRSA). There was significant resistance to levofloxacin (18 eyes, 9.0%) and gentamicin (12 eyes, 6.0%), and no vancomycin-resistant bacteria were detected. The donor factors did not correlate with the prevalence of bacterial contamination in our criteria. Pre-banking microbial assessment allows for microbial detection, bacterial susceptibility and resistance testing. This is useful for developing preservation mediums containing effective spectrum antibiotic agents for high quality control of corneal banking.

Corneal iron ring after conductive keratoplasty.

Science.gov (United States)

Kymionis, George D; Naoumidi, Tatiana L; Aslanides, Ioannis M; Pallikaris, Ioannis G

2003-08-01

To report formation of corneal iron ring deposits after conductive keratoplasty. Observational case report. Case report. A 54-year-old woman underwent conductive keratoplasty for hyperopia. One year after conductive keratoplasty, iron ring pattern pigmentation was detected at the corneal epithelium of both eyes. This is the first report of the appearance of corneal iron ring deposits following conductive keratoplasty treatment in a patient. It is suggested that alterations in tear film stability, resulting from conductive keratoplasty-induced changes in corneal curvature, constitute the contributory factor for these deposits.

Clinical Validation of Point-Source Corneal Topography in Keratoplasty

NARCIS (Netherlands)

Vrijling, A C L; Braaf, B.; Snellenburg, J.J.; de Lange, F.; Zaal, M.J.W.; van der Heijde, G.L.; Sicam, V.A.D.P.

2011-01-01

Purpose. To validate the clinical performance of point-source corneal topography (PCT) in postpenetrating keratoplasty (PKP) eyes and to compare it with conventional Placido-based topography. Methods. Corneal elevation maps of the anterior corneal surface were obtained from 20 post-PKP corneas using

Late occurrence of granular dystrophy in bilateral keratoconus: Penetrating keratoplasty and long-term follow-up

Directory of Open Access Journals (Sweden)

Varsha M Rathi

2011-01-01

Full Text Available We report a rare case of keratoconus with granular dystrophy with a follow-up of two decades, documenting the sequential presentation of two diseases confirmed by histology and genetic studies. A 13-year-old boy was diagnosed in 1988 with keratoconus in both eyes (BE based on slit-lamp biomicroscopy findings of corneal ectasia in BE accompanied by Fleischer′s ring, Vogt′s striae, a small, old, healed hydrops. The left eye (LE had central corneal thinning and scar in the central area involving the mid and posterior stroma secondary to healed hydrops. Penetrating keratoplasty (PKP was advised. The boy was lost to follow-up till 1991 and presented with white, dot-like opacities in the central cornea in the RE only, suggestive of granular corneal dystrophy. Similar findings of white, dot-like opacities were noted in the LE in 1995 and the patient subsequently underwent PKP in BE. Histopathology of corneal buttons confirmed the presence of patchy, crystal-like orange deposits, which stained bright red with Masson′s trichrome. Mutational analysis of the TGFBI gene in patient′s DNA revealed a heterozygous mutation corresponding to a change in Arg555Trp in the keratoepithelin protein. Granular dystrophy recurred after 8 years in the RE.

HERPES VIRUS CONTAMINATION OF DONOR’S TISSUE AS A POTENTIAL ETIOLOGY OF CORNEAL GRAFT DISEASE AFTER PENETRATING KERATOPLASTY

Directory of Open Access Journals (Sweden)

E. A. Mironkova

2012-01-01

Full Text Available We present the study of outcomes of PCR-diagnostics directed on detection of DNA of herpes-family viruses in donor’s corneal tissues taken during penetrating keratoplasty (PK. In total, there were 46 patients, who under- went PKs. They were followed up from 14 days till 12 months. PCR-research of fragments of a donor cornea re- vealed existence of DNA in 21.7%. The retrospective analysis showed that in the presence of herpes-virus DNA in donor’s cornea is the risk factor of postoperative complications development and increases the rejection rate 2–3 times, reaching 100% – 70%. Thus the high risk of graft failures remains associated not only with the system immunosupressive therapy which is usually considered as the precondition of activization of chronic infections, but also in the absence of that. It gives the ground to conclude that preoperative preparation of a donor material, especially «fresh» corneas, should include expanded PCR-diagnostics on herpes-viruses and its obligatory dis- carding in cases of positive tests. 

Weighing of risk factors for penetrating keratoplasty graft failure: application of Risk Score System

Directory of Open Access Journals (Sweden)

Abdo Karim Tourkmani

2017-03-01

Full Text Available AIM: To analyze the relationship between the score obtained in the Risk Score System (RSS proposed by Hicks et al with penetrating keratoplasty (PKP graft failure at 1y postoperatively and among each factor in the RSS with the risk of PKP graft failure using univariate and multivariate analysis. METHODS: The retrospective cohort study had 152 PKPs from 152 patients. Eighteen cases were excluded from our study due to primary failure (10 cases, incomplete medical notes (5 cases and follow-up less than 1y (3 cases. We included 134 PKPs from 134 patients stratified by preoperative risk score. Spearman coefficient was calculated for the relationship between the score obtained and risk of failure at 1y. Univariate and multivariate analysis were calculated for the impact of every single risk factor included in the RSS over graft failure at 1y. RESULTS: Spearman coefficient showed statistically significant correlation between the score in the RSS and graft failure (P0.05 between diagnosis and lens status with graft failure. The relationship between the other risk factors studied and graft failure was significant (P<0.05, although the results for previous grafts and graft failure was unreliable. None of our patients had previous blood transfusion, thus, it had no impact. CONCLUSION: After the application of multivariate analysis techniques, some risk factors do not show the expected impact over graft failure at 1y.

Measurements of intraocular pressure by Goldmann tonometry, Tonopen XL, and the transpalpebral tonometer, TGDc-01, after penetrating keratoplasty: a comparativye study.

Science.gov (United States)

Shemesh, Gabi; Waisbourd, Michael; Varssano, David; Michaeli, Adi; Lazar, Moshe; Kurtz, Shimon

2009-08-01

The aim of this study was to compare intraocular pressure (IOP) measurements obtained by Goldmann tonometry (GT), the Tonopen XL, and a new transpalpebral tonometer, TGDc-01, in eyes that had undergone penetrating keratoplasty (PKP). IOP was measured in post-PKP eyes by means of GT, Tonopen XL, and TGDc-01. Central corneal thickness measurements were also obtained for all eyes. Forty-five eyes of 43 patients were enrolled in the study. The mean IOP difference (+/-SD) was -0.42 +/- 5.83 mm Hg between GT and Tonopen and 3.20 +/- 7.55 mm Hg between GT and TGDc-01. The correlation coefficient was 0.84 between GT and Tonopen XL (P tonometer is simply inaccurate or whether avoiding contact with the corneal graft by measuring IOP through the eyelid enables it to provide more accurate IOP readings than those obtained by transcorneal techniques.

A new vision through combined osteo-odonto-keratoplasty: A review

Directory of Open Access Journals (Sweden)

Lakshmi Shetty

2014-01-01

Full Text Available This is an extensive review of osteo-odonto-keratoplasty (OOKP where the vision is restored by using tooth as an implant in the environment of the eye. The window of the soul is our eye and the window of the eye is cornea. This review article aims at discussing the remarkable operation to regain the sight of patients with corneal blindness. In this procedure where a multidisciplinary approach from both oral and maxillofacial surgeon and ophthalmologist contributes to restore vision in the most severe cases of corneal blindness. This involves removing a canine tooth from the patient, shaping and drilling to allow implantation of an artificial plastic corneal device and finally implanting back into the eye few months later. The OOKP, is the keratoprosthesis of choice for end-stage corneal blindness not amenable to penetrating keratoplasty. This transplantation procedure has an autologous dental root-bone lamina complex and buccal mucosal graft to secure the optical cylinder which acts as a ray of vision for corneal blindness. This review comprises the indications, contraindications, and patient assessment and the surgical procedure, complications ,surgical inter professionalism and future scope of OOKP. The source of data for the review has been Pubmed, Medline and all the research studies and published reports on osteo-odonto-keratoplasty. In this complex procedure good results can be obtained with modern technology and expertise.

Confocal microscopy findings in deep anterior lamellar keratoplasty performed after Descemet's stripping automated endothelial keratoplasty

Directory of Open Access Journals (Sweden)

Pang A

2014-01-01

Full Text Available Audrey Pang,1,2 Karim Mohamed-Noriega,1 Anita S Chan,1,3–5 Jodbhir S Mehta1,3 1Singapore National Eye Centre, 2Department of Ophthalmology, Tan Tock Seng Hospital, 3Singapore Eye Research Institute, 4Department of Histopathology, Pathology, Singapore General Hospital, 5Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore Background: This study describes the in vivo confocal microscopy findings in two patients who had deep anterior lamellar keratoplasty (DALK following Descemet's stripping automated endothelial keratoplasty (DSAEK. Methods: The study reviewed the cases of two patients who first underwent DSAEK followed by DALK when their vision failed to improve due to residual stromal scarring. In the first case, a DSAEK was performed for a patient with pseudophakic bullous keratopathy. After surgery, the patient's vision failed to improve satisfactorily due to residual anterior stromal opacity and irregularity. Subsequently, the patient underwent a DALK. The same two consecutive operations were performed for a second patient with keratoconus whose previous penetrating keratoplasty had failed and had secondary graft ectasia. In vivo confocal microscopy was performed 2 months after the DALK surgery in both cases. Results: At 3 months after DALK, the best-corrected visual acuity was 6/30 in case 1 and 6/24 in case 2. In vivo confocal microscopy in both cases revealed the presence of quiescent keratocytes in the stroma layers of the DSAEK and DALK grafts, which was similar in the central and peripheral cornea. There was no activated keratocytes or haze noted in the interface between the grafts. Conclusion: Our short-term results show that performing a DALK after a DSAEK is an effective way of restoring cornea clarity in patients with residual anterior stromal opacity. In vivo confocal microscopy showed that there were no activated keratocytes seen in the interface of the grafts, which suggests

Microkeratome-assisted lamellar keratoplasty for keratoconus: stromal sandwich.

Science.gov (United States)

Bilgihan, Kamil; Ozdek, Sengül C; Sari, Ayça; Hasanreisoglu, Berati

2003-07-01

To evaluate microkeratome-assisted lamellar keratoplasty for the treatment of keratoconus when it is not possible to correct the astigmatic ametropia with contact lenses. Ophthalmology Department, School of Medicine, Gazi University, Ankara, Turkey. This prospective study comprised 9 eyes of 7 keratoconus patients with contact lens intolerance. The donor cornea was prepared with a microkeratome and punched with a 7.25 mm or 7.50 mm trephine. Following the creation of a standard 9.0 mm corneal flap in the host cornea, the donor stromal button was implanted under this corneal flap like a sandwich. Transepithelial photorefractive keratectomy or laser in situ keratomileusis was performed when the corneal topography and refraction stabilized by the end of the sixth postoperative month. Follow-up ranged from 7 to 22 months. All patients gained 5 or more lines (mean 7.2 lines +/- 1.6 [SD]), and no patient lost a line of vision. The mean corneal thickness was 432.7 +/- 36.1 micrometers preoperatively and 578.1 +/- 45.1 micrometers after refractive surgery. The early visual results of this surgical technique are promising and seem to be comparable to those with penetrating keratoplasty.

Evaluation of an interlaced triple procedure: penetrating keratoplasty, extracapsular cataract extraction, and nonopen-sky intraocular lens implantation.

Science.gov (United States)

Yang, Shuo; Wang, Bin; Zhang, Yangyang; Zhai, Hualei; Wang, Junyi; Wang, Shuang; Xie, Lixin

2017-09-01

To evaluate an interlaced triple procedure that involved penetrating keratoplasty (PKP), extracapsular cataract extraction (ECCE) using diathermy capsulotomy, and nonopen-sky intraocular lens (IOL) implantation.This retrospective study involved data from 34 patients who were diagnosed with severe corneal opacities and cataracts. These patients were divided into an interlaced procedure group (21 patients) and a traditional procedure group (13 patients). In the interlaced group, the method of continuous curvilinear capsulorhexis (CCC) was completed via diathermy capsulotomy. The donor corneal button was sutured at 8 positions (at equal intervals) using 10-0 nylon sutures, and the IOL was inserted into the capsular bag using a closed anterior chamber approach at the 10:30 to 12 o'clock positions between the sutures. In the traditional group, CCC was completed using side-port capsular forceps, and the IOL was implanted using an open anterior chamber approach.In the interlaced group, the CCC, open-sky, and total operation times were significantly shorter than in the traditional group (P < .05). Neither the best-corrected visual acuity (BCVA) nor corneal endothelial cell density was significantly different between the groups at 1 and 6 months after the operation.This interlaced triple procedure for the treatment of corneal diseases with cataracts appears to be feasible and practical.

[Transpalpebral tonometry with a digital tonometer in healthy eyes and after penetrating keratoplasty].

Science.gov (United States)

Amm, M; Hedderich, J

2005-01-01

The Goldmann applanation technique established itself as gold standard for clinical intraocular pressure (IOP) measurement. But the device measures by corneal touch and presupposes corneal conditions within a normal range. So precise determination of IOP is crucial in corneal disorders and after corneal surgery. This pilot study presents tonometry data of normal and postkeratoplasty eyes measured transpalpebrally with a digital tonometer in comparison to Goldmann tonometry. The TGDc-01 tonometer is based on a ballistic principle of measurement. IOP was measured in 50 healthy eyes (group 1) and 40 eyes after penetrating keratoplasty (group 2) first by the TGDc-01 and after 3 minutes by Goldmann tonometry (Haag-Streit). Subjective refraction, keratometry and ultrasonic pachymetry were performed in all eyes. The IOP measurements in the postkeratoplasty eyes were done when corneal epithelium was fully closed and only a medium suture edema could be observed. The Pearson's product-moment correlation was r=0,46 for group 1 and 0,65 for group 2. Using the concordance correlation coefficient the value showed a reproducibility index of r(c)=0,44 in group 1 and r(c)=0,60 in group 2. Following the Bland-Altman-analysis 58% of the cases in group 1 had a difference between the two instruments of maximum 3 mmHg. In group 2, 53,5% of the eyes showed an absolute difference between Goldmann and TDGc-01 of 3 mmHg or less. A transpalpebral measurement technique-avoiding corneal contact-seems to be an alternative choice in patients with corneal pathologies and after corneal surgery. The TGDc-01 tonometer provided mostly similar results compared to the Goldmann device, but with fluctuations. Keeping the deviations between the two methods in mind we recommend, however, the use of the transpalpebral approach only in combination with other techniques (palpation, indentation) to obtain enough reliability of IOP information in problem eyes.

Black diaphragm intraocular lens implantation and penetrating keratoplasty in aphakic eyes with traumatic aniridia

Directory of Open Access Journals (Sweden)

Xiao-Guang Dong

2013-04-01

Full Text Available AIM: To evaluate the long-term outcome of implantation of black diaphragm intraocular (BDI lens combined with penetrating keratoplasty (PKP for managing aphakic eyes with traumatic aniridia and corneal damage. METHODS: Six aphakic eyes of six patients with traumatic aniridia and corneal damage had BDI lens implantation at Qingdao Eye Hospital, Shandong Eye Institute from June 2008 to November 2011. Medical records of the patients were reviewed. Three patients received PKP and after 12-18months were implanted with BDI lens. The other three patients completed PKP and BDI lens implantation at the same time. The corrected visual acuity, intraocular pressure and number of corneal endothelial cells were monitored. RESULTS: The patients were followed up for an average of 24.3±12.1months (range 14-48 months. All BDI lenses were located well. The best corrected visual acuity got improved in 5 patients (0.1-1.0 and decreased in 1 patient from 0.4 to 0.2. Three patients had normal intraocular pressure (IOP after implantation. Two patients required antiglaucoma medications to control IOP within the normal range and 1 patient implanted Ahmed glaucoma valve to control IOP. The corneal grafts kept transparent in all eyes and the corneal endothelial counting >1 000/mm2, although two patients experienced acute graft rejection and loss more than 30% corneal endothelial cells. CONCLUSION: Implantation of BDI lens combined with PKP is an effective option for managing aphakic eyes with traumatic aniridia and corneal damage. Although the results in our study are encouraging, additional studies of the long-term safety and efficacy are required. A larger study population and longer follow-up may be beneficial.

Safety of prophylactic intracameral moxifloxacin ophthalmic solution after cataract surgery in patients with penetrating keratoplasty

Directory of Open Access Journals (Sweden)

Osman Sevki Arslan

2014-10-01

Full Text Available AIM:To determine the safety of prophylactic intracameral moxifloxacin after cataract surgery in patients with penetrating keratoplasty (PKP.METHODS:In this retrospective study of consecutive patients who had phacoemulsification cataract surgery after PKP, were treated with intracameral moxifloxacin 0.5% ophthalmic solution (0.5 mg/0.1 mL. The main outcome measures were anterior chamber reaction, best corrected visual acuity (BCVA, corneal endothelial cell count (ECC, and central corneal thickness (CCT.RESULTS:Fifty-five patients were recruited (26 males, 29 females. The mean age was 54.36±4.97y (range 45-64y. All eyes had improved postoperative BCVA. The mean BCVA was 0.25 preoperatively and 0.57 postoperatively, which was statistically significant (P<0.001. One eye had 3+, 7 eyes had 2+, 12 eyes had 1+ and 8 eyes had trace amount of aqueous cells on the first day after surgery. All eyes had no anterior chamber cells at subsequent follow up examinations. Effective phacoemulsification time was 4.33±1.01s. The mean ECC was 2340.20 cells/mm2 preoperatively and 1948.75 cells/mm2 1mo postoperatively (P<0.001. The increase of 21.09 µm in postoperative pachymetry 1mo after surgery was statistically significant (P<0.001.CONCLUSION: No untoward effects were observed after intracameral injection of moxifloxacin (0.5 mg/0.1 mL in terms of anterior chamber reaction, CCT, ECC, and visual rehabilitation at the conclusion of cataract surgery in patients with PKP.

Subluxation of iris-sutured intraocular lenses and results of a closed chamber technique for repositioning after penetrating keratoplasty.

Science.gov (United States)

Jabbur, Nada S; Akpek, Esen Karamursel; Stark, Walter J

2005-05-01

To describe subluxation of iris-fixated intraocular lenses (IOLs) after penetrating keratoplasty (PK) as a postoperative complication and report the long-term outcomes of a closed-chamber refixation technique used in the management. This was a retrospective, noncomparative interventional case series in which 19 consecutive patient charts with a subluxated iris-fixated IOL after PK were retrospectively reviewed. Fourteen of the patients underwent surgery using a closed-chamber refixation technique. These patients were evaluated for visual outcome and surgical complications associated with the procedure. In 13 patients, postoperative follow-up was available. In all 13 cases, the fixated IOL appeared stable and remained well positioned during a follow-up period of 56 months (range, 6-122). All patients (100%) achieved improved uncorrected visual acuity. The postoperative visual acuity ranged from 20/20 to 20/100 with a mean of 20/40. Vitreous hemorrhage occurred in 1 patient, and an additional patient required a second surgery using the same technique. Both of these patients did well with a final visual acuity of 20/40 and 20/50, respectively. Subluxation of iris-fixated IOL after PK can occur as a postoperative complication. The technique that we herein describe enables secure refixation of subluxated IOLs and yields favorable long-term results.

Candida Endophthalmitis After Descemet Stripping Automated Endothelial Keratoplasty With Grafts From Both Eyes of a Donor With Possible Systemic Candidiasis.

Science.gov (United States)

Palioura, Sotiria; Sivaraman, Kavitha; Joag, Madhura; Sise, Adam; Batlle, Juan F; Miller, Darlene; Espana, Edgar M; Amescua, Guillermo; Yoo, Sonia H; Galor, Anat; Karp, Carol L

2018-04-01

To report 2 cases with late postoperative Candida albicans interface keratitis and endophthalmitis after Descemet stripping automated endothelial keratoplasty (DSAEK) with corneal grafts originating from a single donor with a history of presumed pulmonary candidiasis. Two patients underwent uncomplicated DSAEK by 2 corneal surgeons at different surgery centers but with tissue from the same donor and were referred to the Bascom Palmer Eye Institute with multifocal infiltrates at the graft-host cornea interface 6 to 8 weeks later, and anterior chamber cultures that were positive for the same genetic strain of C. albicans. Immediate explantation of DSAEK lenticules and daily intracameral and instrastromal voriconazole and amphotericin injections failed to control the infection. Thus, both patients underwent therapeutic penetrating keratoplasty with intraocular lens explantation, pars plana vitrectomy, and serial postoperative intraocular antifungal injection. Both patients are doing well at 2 years postoperatively with best-corrected vision of 20/20 and 20/30+ with rigid gas permeable lenses. One patient required repeat optical penetrating keratoplasty and glaucoma tube implantation 1 year after the original surgery. Literature review reveals that donor lenticule explantation and intraocular antifungals are often inadequate to control fungal interface keratitis, and a therapeutic graft is commonly needed. Interface fungal keratitis and endophthalmitis due to infected donor corneal tissue is difficult to treat, and both recipients of grafts originating from the same donor are at risk of developing this challenging condition.

Clinical outcomes after combined Ahmed glaucoma valve implantation and penetrating keratoplasty or pars plana vitrectomy.

Science.gov (United States)

Lee, Jin Young; Sung, Kyung Rim; Tchah, Hung Won; Yoon, Young Hee; Kim, June Gone; Kim, Myoung Joon; Kim, Jae Yong; Yun, Sung-Cheol; Lee, Joo Yong

2012-12-01

To evaluate whether a combination of penetrating keratoplasty (PKP) or pars plana vitrectomy (PPV) and Ahmed glaucoma valve (AGV) implantation affords a level of success similar to that of AGV implantation alone. Eighteen eyes underwent simultaneous PPV and AGV, 14 eyes with PKP and AGV and 30 eyes with AGV implantation alone were evaluated. Success was defined as attainment of an intraocular pressure (IOP) >5 and glaucoma medication. Kaplan-Meier survival analysis was performed to compare cumulative survival between the combined surgery groups and the AGV implantation-alone group. Cox proportional hazard regression analysis was conducted to identify factors predictive of success in each of the three groups. Mean (±standard deviation) preoperative IOP was 30.2 ± 10.2 mmHg in the PKP + AGV, 35.2 ± 9.8 mmHg in the PPV + AGV, and 36.2 ± 10.1 mmHg in the AGV implantation-alone group. The cumulative success rate at 18 months was 66.9%, 73.2%, and 70.8% in the three groups, respectively. Neither combined surgery group differed significantly in terms of cumulative success rate compared with the AGV implantation-alone group (p = 0.556, p = 0.487, respectively). The mean number of preoperative anti-glaucoma medications prescribed was significantly associated with success in the PKP + AGV implantation group (hazard ratio, 2.942; p = 0.024). Either PKP or PPV performed in conjunction with AGV implantation afforded similar success rates compared to patients treated with AGV implantation alone. Therefore, in patients with refractory glaucoma who have underlying corneal or retinal pathology requiring treatment with PKP or PPV, AGV implantation can be performed simultaneously.

Corneal endothelial rejection after penetrating keratoplasty treated with intravenous and topic corticosteroid: one year follow up

Directory of Open Access Journals (Sweden)

Ricardo Yuji Abe

2013-02-01

Full Text Available OBJECTIVE: To analyze the recovery of visual acuity (VA and graft survival after first episode of endothelial rejection in penetrating keratoplasty (PKP treated with intravenous (IV and topic corticosteroid. METHODS: Interventional, prospective, non-comparative case series study evolving 32 PKP patients in one year follow up, who presented first episode of corneal endothelial rejection. The patients were submitted to 500 mg IV injection of methylprednisolone in association with topical prednisolone. Main outcome measures included VA recovery and corneal edema regression. Second outcome included new rejections and graft failure. Multivariate analysis techniques were used to estimate rates of graft outcome events and the impact of risk factors. RESULTS: A total of 32 eyes from 32 patients (13 male and 19 female were included in the study. The mean VA (in number of letters before rejection was 48 (22 to 88 letters. Patients treated within 7 days or less of initial symptoms had better VA recovery, corneal edema regression and less graft failure (p<0.001. Patients with previous ocular surgery had worse VA recovery and more graft failure (p<0.047. CONCLUSION: The association between the other risk factors and the outcomes did not reach statistical significance in the multivariate model because of the small numbers of patients. Methylprednisolone in association with topical prednisolone is an alternative treatment for graft rejection. Our study showed that patients treated within 7 days of symptoms and no previous anterior segment surgery had better visual outcome and graft survival after treatment.

Profit-based conventional resource scheduling with renewable energy penetration

Science.gov (United States)

Reddy, K. Srikanth; Panwar, Lokesh Kumar; Kumar, Rajesh; Panigrahi, B. K.

2017-08-01

Technological breakthroughs in renewable energy technologies (RETs) enabled them to attain grid parity thereby making them potential contenders for existing conventional resources. To examine the market participation of RETs, this paper formulates a scheduling problem accommodating energy market participation of wind- and solar-independent power producers (IPPs) treating both conventional and RETs as identical entities. Furthermore, constraints pertaining to penetration and curtailments of RETs are restructured. Additionally, an appropriate objective function for profit incurred by conventional resource IPPs through reserve market participation as a function of renewable energy curtailment is also proposed. The proposed concept is simulated with a test system comprising 10 conventional generation units in conjunction with solar photovoltaic (SPV) and wind energy generators (WEG). The simulation results indicate that renewable energy integration and its curtailment limits influence the market participation or scheduling strategies of conventional resources in both energy and reserve markets. Furthermore, load and reliability parameters are also affected.

Topographic characteristics after Descemet's membrane endothelial keratoplasty and Descemet's stripping automated endothelial keratoplasty.

Directory of Open Access Journals (Sweden)

Takahiko Hayashi

Full Text Available To investigate the topographic characteristics of the posterior corneal surface after Descemet's endothelial membrane keratoplasty (DMEK and Descemet's stripping automated endothelial keratoplasty (DSAEK and their effects on postoperative visual acuity.Nineteen eyes of 19 patients after DMEK, 23 eyes of 23 patients after DSAEK, and 18 eyes of 18 control subjects were retrospectively analyzed. Best spectacle-corrected visual acuity (BSCVA, aberration factors (higher-order aberrations [HOAs], spherical aberrations [SAs], and coma aberrations [Comas] at 6.0 mm were evaluated preoperatively and at 1, 3, and 6 months postoperatively. The posterior refractive pattern of the topography map was classified into 5 grades (0-5 (posterior color grade using anterior segment optical coherence tomography. Correlations between BSCVA and some factors (abbreviation factors, posterior color grade were analyzed.BSCVA was significantly better after DMEK than after DSAEK (P < 0.001. Posterior HOAs, SAs, and Comas after each type of endothelial keratoplasty were significantly greater compared to control (P < 0.01. Posterior HOAs, total/anterior/posterior SAs, and posterior color grade were significantly lower in the DMEK group than in the DSAEK group at 3 months (P < 0.024 [posterior HOAs], P = 0.047 [total SA], P < 0.001 [anterior SAs], P = 0.021 [posterior SAs], and P < 0.001 [posterior color grade] and 6 months postoperatively (P = 0.034 [posterior HOAs], P < 0.001 [total SAs], P < 0.001 [anterior SAs], P = 0.013 [posterior SAs], and P = 0.004 [posterior color grade]. BSCVA was significantly correlated with HOAs, SAs, and posterior color grade (P < 0.001 for all except anterior HOAs [P = 0.004].High posterior color grades were associated with larger aberration factors and had a negative effect on visual function after endothelial keratoplasty. Rapid improvement of visual function after DMEK may be attributed to less change at the posterior surface.

Combined HLA matched limbal stem cells allograft with amniotic membrane transplantation as a prophylactic surgical procedure to prevent corneal graft rejection after penetrating keratoplasty: case report

Directory of Open Access Journals (Sweden)

Paolo Capozzi

2014-09-01

Full Text Available Purpose. To determine if the use of combined HLA matched limbal stem cells allograft with amniotic membrane transplantation (AMT is a safe and effective prophylactic surgical procedure to prevent corneal graft after penetrating keratoplasty (PK. Methods. We report the case of a 17 years old patient with a history of congenital glaucoma, trabeculectomy and multiple corneal graft rejections, presenting total limbal cell deficiency. To reduce the possibility of graft rejection in the left eye after a new PK, a two step procedure was performed. At first the patient underwent a combined HLA matched limbal stem cells allograft (LAT and AMT and then, 10 months later, a new PK. Results. During 12 months of follow-up, the corneal graft remained stable and smooth, with no sign of graft rejection. Conclusions. In our patient, the prophylactic use of LAT from HLA-matched donors and AMT before PK, may result in a better prognosis of corneal graft survival.

Complications and Management of Deep Anterior Lamellar Keratoplasty

Directory of Open Access Journals (Sweden)

Banu Torun Acar

2014-10-01

Full Text Available Objectives: To report the intraoperative and postoperative follow-up complications and management of these in deep anterior lamellar keratoplasty (DALK surgery. Materials and Methods: Two hundred eighty-four eyes of 252 patients followed up in our cornea clinic who underwent DALK using Anwar’s big-bubble technique with healthy Descemet’s membrane and endothelium were included in this study. Intraoperative and postoperative complications as well as the management and treatment of these complications were evaluated. Results: Big bubble was created in 220 (77.5% eyes of 284 eyes, and lamellar dissection was performed in 64 (22.5% eyes. Perforation occurred during trephination in 4 eyes, and the procedure was accomplished by penetrating keratoplasty (PK. Intraoperative microperforation occurred in 44 eyes. Perforation enlarged in 4 eyes and PK was performed. Operation was continued in 40 eyes with air injection into the anterior chamber. In postopertive follow-up period, double anterior chamber (DAC occurred in 32 of 40 eyes. DAC spontaneously regressed in 8 eyes, and air was given into the anterior chamber with a second surgical intervention in 24 eyes. DAC improved in 20 eyes. Four eyes underwent PK. Fungal keratitis evolved at the interface in one eye, because of no healing during the follow-up period, this eye underwent PK under antifungal therapy. Eyes with interface haze and Descemet’s membrane folds were followed. Conclusion: DALK is a difficult technique with a steep learning curve. In addition to the complications seen in PK, specific complications can occur in lamellar surgery. (Turk J Ophthalmol 2014; 44: 337-40

Early Ahmed glaucoma valve implantation after penetrating keratoplasty leads to better outcomes in an Asian population with preexisting glaucoma.

Directory of Open Access Journals (Sweden)

Ming-Cheng Tai

Full Text Available BACKGROUND: To evaluate the efficacy of Ahmed Glaucoma Valve (AGV surgery and the optimal interval between penetrating keratoplasty (PKP and AGV implantation in a population of Asian patients with preexisting glaucoma who underwent PKP. METHODOLOGY/PRINCIPAL FINDINGS: In total, 45 eyes of 45 patients were included in this retrospective chart review. The final intraocular pressures (IOPs, graft survival rate, and changes in visual acuity were assessed to evaluate the outcomes of AGV implantations in eyes in which AGV implantation occurred within 1 month of post-PKP IOP elevation (Group 1 and in eyes in which AGV implantation took place more than 1 month after the post-PKP IOP evaluation (Group 2. Factors that were associated with graft failure were analyzed, and the overall patterns of complications were reviewed. By their final follow-up visits, 58% of the patients had been successfully treated for glaucoma. After the operation, there were no statistically significant differences between the groups with respect to graft survival (p = 0.98, but significant differences for IOP control (p = 0.049 and the maintenance of visual acuity (VA (p21 mm Hg. The most common surgical complication, aside from graft failure, was hyphema. CONCLUSIONS/SIGNIFICANCE: Early AGV implantation results in a higher probability of AGV survival and a better VA outcome without increasing the risk of corneal graft failure as a result of post-PKP glaucoma drainage tube implantation.

Early Ahmed Glaucoma Valve Implantation after Penetrating Keratoplasty Leads to Better Outcomes in an Asian Population with Preexisting Glaucoma

Science.gov (United States)

Tai, Ming-Cheng; Chen, Yi-Hao; Cheng, Jen-Hao; Liang, Chang-Min; Chen, Jiann-Torng; Chen, Ching-Long; Lu, Da-Wen

2012-01-01

Background To evaluate the efficacy of Ahmed Glaucoma Valve (AGV) surgery and the optimal interval between penetrating keratoplasty (PKP) and AGV implantation in a population of Asian patients with preexisting glaucoma who underwent PKP. Methodology/Principal Findings In total, 45 eyes of 45 patients were included in this retrospective chart review. The final intraocular pressures (IOPs), graft survival rate, and changes in visual acuity were assessed to evaluate the outcomes of AGV implantations in eyes in which AGV implantation occurred within 1 month of post-PKP IOP elevation (Group 1) and in eyes in which AGV implantation took place more than 1 month after the post-PKP IOP evaluation (Group 2). Factors that were associated with graft failure were analyzed, and the overall patterns of complications were reviewed. By their final follow-up visits, 58% of the patients had been successfully treated for glaucoma. After the operation, there were no statistically significant differences between the groups with respect to graft survival (p = 0.98), but significant differences for IOP control (p = 0.049) and the maintenance of visual acuity (VA) (pglaucoma, a history of previous PKP, and a preoperative IOP that was >21 mm Hg. The most common surgical complication, aside from graft failure, was hyphema. Conclusions/Significance Early AGV implantation results in a higher probability of AGV survival and a better VA outcome without increasing the risk of corneal graft failure as a result of post-PKP glaucoma drainage tube implantation. PMID:22629464

[Astigmatic keratotomy with the femtosecond laser: correction of high astigmatisms after keratoplasty].

Science.gov (United States)

Kook, D; Bühren, J; Klaproth, O K; Bauch, A S; Derhartunian, V; Kohnen, T

2011-02-01

The purpose of this study was to evaluate a novel technique for the correction of postoperative astigmatism after penetrating keratoplasty with the use of the femtosecond laser creating astigmatic keratotomies (femto-AK) in the scope of a retrospective case series. Clinical data of ten eyes of nine patients with high residual astigmatism after penetrating keratoplasty undergoing paired femto-AK using a 60-kHz femtosecond laser (IntraLase™, AMO) were analyzed. A new software algorithm was used to create paired arcuate cuts deep into the donor corneal button with different cut angles. Target values were refraction, uncorrected visual acuity, best corrected visual acuity, topographic data (Orbscan®, Bausch & Lomb, Rochester, NY, USA), and corneal wavefront analysis using Visual Optics Lab (VOL)-Pro 7.14 Software (Sarver and Associates). Vector analysis was performed using the Holladay, Cravy and Koch formula. Statistical analysis was performed to detect significances between visits using Student's t test. All procedures were performed without any major complications. The mean follow-up was 13 months. The mean patient age was 48.7 years. The preoperative mean uncorrected visual acuity (logMAR) was 1.27, best corrected visual acuity 0.55, mean subjective cylinder -7.4 D, and mean topometric astigmatism 9.3 D. The postoperative mean uncorrected visual acuity (logMAR) was 1.12, best corrected visual acuity 0.47, mean subjective cylinder -4.1 D, and mean topometric astigmatism 6.5 D. Differences between corneal higher order aberrations showed a high standard deviation and were therefore not statistically significant. Astigmatic keratotomy using the femtosecond laser seems to be a safe and effective tool for the correction of higher corneal astigmatisms. Due to the biomechanical properties of the cornea and missing empirical data for the novel femto-AK technology, higher numbers of patients are necessary to develop optimal treatment nomograms.

Pseudomonas aeruginosa endophthalmitis after penetrating keratoplasty transmitted from the same donor to two recipients confirmed by pulsed-field gel electrophoresis.

Science.gov (United States)

Oguido, Ana Paula Miyagusko Taba; Casella, Antonio Marcelo Barbante; Hofling-Lima, Ana Luisa; Pacheco, Sergio Arruda; Bispo, Paulo José Martins; Marques, Fernanda

2011-09-01

Two devastating cases of multidrug-resistant Pseudomonas aeruginosa endophthalmitis after keratoplasty as the result of transmission from the same donor were confirmed by pulsed-field gel electrophoresis. Strategies for preventing donor-to-host transmission, such as the use of antimicrobial agents of greater efficacy and better methods for detecting microorganisms in preservation medium, could minimize this type of transmission.

[Remote results of high myopia surgical correction by tunnel keratoplasty ].

Science.gov (United States)

Dushin, N V; Beliaev, V S; Gonchar, P A; Barashkov, V I; Kravchinina, V V; Frolov, M A

2000-01-01

Remote results evidence high refraction efficiency of tunnel keratoplasty, stable results being observed for up to 15 years. A total of 104 operations (58 patients) were analyzed for a period of observation of more than 10 years. The patients' ages varied from 17 to 52 years, there were 34 women and 24 men. The main advantage of interlamellar refraction meridional keratoplasty is easiness of operation. At present it is the operation of choice for dosed reduction of eye refraction aimed at correction of high myopia and astigmatism. The possibility of correcting residual myopia after keratotomy and repair of refraction abnormalities resultant from perforating keratoplasty is particularly interesting. The possibility of regulating the corrective effect in remote periods by replacing the implants also deserves attention. Hence, low traumatism, high efficiency, and stability of the refraction effect once more confirm our recommendation to use tunnel keratoplasty in clinical practice.

Long-term outcomes of penetrating keratoplasty in keratoconus:analysis of the factors associated with final visual acuities

Directory of Open Access Journals (Sweden)

Jin A Choi

2014-06-01

Full Text Available AIM: To investigate the long-term results of penetrating keratoplasty (PK in patients with keratoconus (KC and to evaluate factors that might influence the final visual outcome.METHODS:We retrospectively reviewed the data of all patients with clinical KC who had undergone PK by a single corneal surgeon in a single center from May 1980 to December 2005. The age of the patients, preoperative best-corrected visual acuity (BCVA, corneal thickness, death to preservation time, and preservation to transplantation time were recorded. Additionally, postoperative complications such as graft rejection, development of glaucoma and specular microscopy were checked during the follow-up.RESULTS:Sixty-nine eyes from 69 patients were finally included. The follow-up period was 8.64±6.13y. Graft rejection occurred in 4 eyes of 69 cases (5.8%, and the time to graft rejection was 2.1±1.3y. A Kaplan–Meier survival analysis showed that the estimated cumulative probability of graft rejection at 6, 13, and 17y after PK were 95.6%, 90.0%, and 78.8%, respectively. When we evaluated factors that might influence final BCVA in eyes, no disparity donor-host trephine size (same graft size as well as higher spherical equivalent, and average K-value were associated with higher final BCVA. (P=0.006, 0.051, 0.092, and 0.021 in eyes with follow-up <8y; P=0.068, 0.065, and 0.030 in eyes with follow-up ≥8y, respectively.CONCLUSION: The long-term results of PK in patients with KC were favorable with a high percentage of good BCVA. Less myopic change and low average K-reading, as well as a surgical technique using the same size donor-recipient button may provide better visual outcomes particularly in patients with KC.

Endothelial cell density after deep anterior lamellar keratoplasty (Melles technique)

NARCIS (Netherlands)

Van Dooren, BTH; Mulder, PGH; Nieuwendaal, CP; Beekhuis, WH; Melles, GRJ

PURPOSE: To measure the recipient endothelial cell loss after the Melles technique for deep anterior lamellar keratoplasty. METHODS: In 21 eyes of 21 patients, a deep anterior lamellar keratoplasty procedure was performed. Before surgery and at 6, 12, and 24 months after surgery, specular microscopy

Endothelial cell density after deep anterior lamellar keratoplasty (Melles technique)

NARCIS (Netherlands)

van Dooren, Bart T. H.; Mulder, Paul G. H.; Nieuwendaal, Carla P.; Beekhuis, W. Houdijn; Melles, Gerrit R. J.

2004-01-01

To measure the recipient endothelial cell loss after the Melles technique for deep anterior lamellar keratoplasty. In 21 eyes of 21 patients, a deep anterior lamellar keratoplasty procedure was performed. Before surgery and at 6, 12, and 24 months after surgery, specular microscopy was performed to

Contact Lens Visual Rehabilitation in Keratoconus and Corneal Keratoplasty

Directory of Open Access Journals (Sweden)

Yelda Ozkurt

2012-01-01

Full Text Available Keratoconus is the most common corneal distrophy. It’s a noninflammatory progressive thinning process that leads to conical ectasia of the cornea, causing high myopia and astigmatism. Many treatment choices include spectacle correction and contact lens wear, collagen cross linking, intracorneal ring segments implantation and finally keratoplasty. Contact lenses are commonly used to reduce astigmatism and increase vision. There are various types of lenses are available. We reviewed soft contact lenses, rigid gas permeable contact lenses, piggyback contact lenses, hybrid contact lenses and scleral-semiscleral contact lenses in keratoconus management. The surgical option is keratoplasty, but even after sutur removal, high astigmatism may stil exists. Therefore, contact lens is an adequate treatment option to correct astigmatism after keratoplasty.

Deep anterior lamellar keratoplasty in the management of keratoconus

Directory of Open Access Journals (Sweden)

Rajesh Fogla

2013-01-01

Full Text Available Advanced cases of keratoconus often require surgical intervention to restore corneal anatomy and improve eyesight. Penetrating keratoplasty (PK although commonly performed has potential risk of immunological rejection and is now no longer automatically the first choice of surgery. DALK procedures have evolved, which allows surgical replacement of recipient′s corneal stroma, leaving behind healthy descemet membrane (DM and endothelium. This reduces the risk of allograft endothelial rejection and late graft failure. In recent times, DALK techniques have led to significant improvements in visual outcome and current results are comparable to PK. Big bubble technique of DALK has become the most popular among the various surgical techniques described. Manual near DM DALK also gives good outcome although the visual recovery is often delayed. Future integration of femtosecond laser technology along with diagnostic imaging technology is likely to further improve outcomes of DALK in keratoconus.

Corneal collagen cross-linking in the stabilization of PRK, LASIK, thermal keratoplasty, and orthokeratology.

Science.gov (United States)

Nguyen, Michelle K; Chuck, Roy S

2013-07-01

To describe the use of corneal collagen cross-linking (CXL) and its efficacy in the stabilization of keratorefractive procedures, including PRK, laser in-situ keratomileusis (LASIK), thermal keratoplasty, and orthokeratology. Since its introduction, CXL has quickly gained interest in the treatment of ectactic disorders due to its ability to increase the biomechanical stability of the cornea. In its earliest use, it has shown to be effective in the treatment of both keratoconus and post-LASIK ectasia. More recent studies of CXL in combination with keratorefractive procedures have shown varying degrees of success. CXL with PRK has shown to be effective in slowing or halting the progression of keratoconus, pellucid marginal degeneration, and post-LASIK ectasia, in addition to potentially decreasing or delaying the need for penetrating keratoplasty. Several small case series have also demonstrated improved stability and efficacy of PRK and LASIK when combined with CXL, as well as a potentially decreased risk of postprocedure ectasia. In conjunction with thermokeratoplasty and orthokeratology, CXL has shown improved but only temporary results in the treatment of keratoconus. Future studies are needed to determine the efficacy and long-term stability of CXL in combination with keratorefractive procedures, as well as to address possible complications.

Evaluation of the Role of Umbilical Cord Serum and Autologous Serum Therapy in Reepithelialization After Keratoplasty: A Randomized Controlled Clinical Trial.

Science.gov (United States)

Kamble, Neha; Sharma, Namrata; Maharana, Prafulla K; Bandivadekar, Pooja; Nagpal, Ritu; Agarwal, Tushar; Velpandian, Thirumurthy; Mittal, Suneeta; Vajpayee, Rasik B

2017-09-01

To evaluate the role of umbilical cord serum (UCS) and autologous serum (AS) therapy in reepithelialization of corneal graft after keratoplasty in a randomized controlled trial. A total of 105 eyes with epithelial defect (ED) after keratoplasty (penetrating keratoplasty-67 and anterior lamellar keratoplasty-38) on the first postoperative day were included in the study. The eyes were randomized into three groups: UCS (n=35), AS (n=35), and artificial tears (AT) (n=35). All patients received standard postoperative medical therapy. The primary outcome measure was time to epithelialization, and secondary outcome measures were best-corrected visual acuity and graft clarity. The ED healed completely in 103 eyes. The mean time for complete reepithelialization was 2.5±2.1, 3.1±2.2, and 4.5±1.4 days in UCS, AS, and AT groups, respectively. The mean percentage decrease in the size of the ED was significantly better in the UCS and AS groups as compared with the AT group (P=0.001). The rate of reepithelialization was comparable between the AS and UCS groups (P=0.3). On bivariate analysis, significant correlation was found between the mean size of postoperative ED, grade of the donor cornea (P=0.001), and the presence of preoperative ED (P=0.001). No complications were associated with the use of serum therapy. Most of the cases of postkeratoplasty corneal ED can be managed with AT only. The serum therapy (AS/UCS) helps in the faster reepithelialization of postkeratoplasty ED as compared with AT and may be considered as a treatment option for early epithelial healing.

Indications for Corneal Transplantation at a Tertiary Referral Center in Tehran

Directory of Open Access Journals (Sweden)

Mohammad Zare

2010-01-01

Full Text Available Purpose: To report the indications and techniques of corneal transplantation at a tertiary referral center in Tehran over a 3-year period. Methods: Records of patients who had undergone any kind of corneal transplantation at Labbafinejad Medical Center, Tehran, Iran from March 2004 to March 2007 were reviewed to determine the indications and types of corneal transplantation. Results: During this period, 776 eyes of 756 patients (including 504 male subjects with mean age of 41.3±21.3 years underwent corneal transplantation. The most common indication was keratoconus (n=317, 40.8% followed by bullous keratopathy (n=90, 11.6%, non-herpetic corneal scars (n=62, 8.0%, infectious corneal ulcers (n=61, 7.9%, previously failed grafts (n=61, 7.9%, endothelial and stromal corneal dystrophies (n=28, 3.6%, and trachoma keratopathy (n=26, 3.3%. Other indications including Terrien′s marginal degeneration, post-LASIK keratectasia, trauma, chemical burns, and peripheral ulcerative keratitis constituted the rest of cases. Techniques of corneal transplantation included penetrating keratoplasty (n=607, 78.2%, deep anterior lamellar keratoplasty (n=108, 13.9%, conventional lamellar keratoplasty (n=44, 5.7%, automated lamellar therapeutic keratoplasty (n=8, 1.0%, and Descemet stripping endothelial keratoplasty (n=6, 0.8% in descending order. The remaining cases were endothelial keratoplasty and sclerokeratoplasty. Conclusion: In this study, keratoconus was the most common indication for penetrating keratoplasty which was the most prevalent technique of corneal transplantation. However, deep anterior lamellar keratoplasty is emerging as a growing alternative for corneal pathologies not involving the endothelium.

Comparação entre os resultados pós-operatórios de pacientes submetidos ao procedimento tríplice e transplante de córnea combinado a fixação secundária de lente intra-ocular Comparison between the postoperative results of triple procedure and combined penetrating keratoplasty/ transsclerally sutured posterior chamber lens implantation

Directory of Open Access Journals (Sweden)

Daniela Maggioni Pereira Leão

2006-08-01

Full Text Available OBJETIVO: Comparar os resultados pós-operatórios de 2 grupos de pacientes submetidos a transplante de córnea com técnicas e tempo cirúrgico diferentes, em relação à abordagem do cristalino e/ou lente intra-ocular. MÉTODOS: Neste estudo retrospectivo foram analisados 37 olhos de pacientes divididos em 2 grupos: extração de catarata, implante de lentes intra-oculares (LIO e transplante de córnea no mesmo tempo cirúrgico - grupo 1 (G1 e extração de catarata sem implante de lentes intra-oculares no primeiro tempo cirúrgico e fixação secundária de lentes intra-oculares associada a transplante de córnea no segundo tempo cirúrgico - grupo 2 (G2. As variáveis estudadas foram: acuidade visual, pressão intra-ocular (PIO, astigmatismo refracional, astigmatismo ceratométrico e complicações pós-operatórias. RESULTADOS: Foi observado melhora da acuidade visual nos 2 grupos (G1 pPURPOSE: To compare the outcomes of two surgical techniques of penetrating keratoplasty with different surgical time, regarding the crystalline and the intraocular lens. METHODS: This retrospective study included 37 patients' eyes divided into 2 groups: extracapsular cataract extraction, posterior chamber intraocular lens implantation and penetrating keratoplasty (Group 1, G1 and transscleral fixation of posterior chamber lens and penetrating keratoplasty (Group 2, G2. The following parameters were recorded: visual acuity, intraocular pressure, refractive astigmatism, complication and keratometric astigmatism. RESULTS: Visual acuity improved in the two groups (G1 p<0.001 and G2 p=0.008. In G2 a significant change for the worse of intraocular pressure outcome was observed when compared with the other group (p=0.014. Regarding refractive and keratometric astigmatism no significant differences between the groups were found. The follow-up was 11 months. CONCLUSION: The most important negative prognostic factor affecting visual acuity was the postkeratoplasty

Changes in corneal sensation, epithelial damage, and tear function after descemet stripping automated endothelial keratoplasty.

Science.gov (United States)

Hirayama, Yumiko; Satake, Yoshiyuki; Hirayama, Masatoshi; Shimazaki-Den, Seika; Konomi, Kenji; Shimazaki, Jun

2013-09-01

To study the ocular surface changes in eyes after Descemet stripping automated endothelial keratoplasty (DSAEK) compared with those after penetrating keratoplasty (PKP). This prospective study compared the changes in 31 eyes of 28 patients who underwent DSAEK (DSAEK group) with those in 15 disease-matched eyes of 15 patients who underwent PKP (PKP group). Corneal epithelial integrity was evaluated using a fluorescein staining score. Corneal sensation was measured with a Cochet-Bonnet esthesiometer. Tear function was evaluated using the Schirmer test, tear clearance test, tear function index, and tear break-up time. The postoperative fluorescein staining score was significantly higher in the PKP group than in the DSAEK group (P = 0.02). Postoperative corneal sensation was significantly better in the DSAEK group than in the PKP group (P sensation after DSAEK was significantly better than the preoperative value (P = 0.02). There were no statistically significant changes in the Schirmer test, tear clearance test, tear function index, or break-up time before and after the surgery in both the DSAEK and PKP groups. No significant differences were observed between the DSAEK and PKP groups after the surgery. Corneal sensation was preserved, and epithelial damage was less severe after DSAEK compared with PKP. Preservation of corneal sensation may contribute to the early recovery of visual function and long-term maintenance of ocular surface health after DSAEK.

Visual outcomes after deep anterior lamellar keratoplasty using donor corneas without removal of Descemet membrane and endothelium

Directory of Open Access Journals (Sweden)

Tatiana Moura Bastos Prazeres

Full Text Available ABSTRACT Purpose: The optical quality of the interface after deep anterior lamellar keratoplasty (DALK using the big-bubble technique has been shown to be excellent, leading to results comparable to penetrating keratoplasty. However, there is little in the literature with respect to the controversy surrounding the preparation of the donor cornea. The purpose of this study was to evaluate visual acuity (VA in patients with keratoconus who underwent DALK without removal of the donor graft endothelium. Methods: The records of 90 patients who underwent DALK without the removal of the Descemet membrane (DM and endothelium were retrospectively reviewed. Data collected included uncorrected VA (UCVA and spectacle-corrected VA (SCVA at 7, 30, 180 days, and 1 year postoperatively. Contact lens-corrected visual acuity (CLVA was evaluated after 1 year of the procedure. Results: UCVA was significantly better than preoperative values at 7 days (p<0.001, 30 days (p<0.001, 180 days (p<0.001, and 1 year (p<0.001 after surgery. The 1-year postoperative mean SCVA and CLVA also improved when compared with preoperative SCVA (p<0.001 for both. Conclusions: DALK utilizing donor corneas with attached Descemet membrane and endothelium results in satisfactory VA in patients with keratoconus.

Laser in situ keratomileusis for residual hyperopic astigmatism after conductive keratoplasty.

Science.gov (United States)

Kymionis, George D; Aslanides, Ioannis M; Khoury, Aghlab N; Markomanolakis, Marinos M; Naoumidi, Tatiana; Pallikaris, loannis G

2004-01-01

To report a case of laser in situ keratomileusis (LASIK) in a patient with previous conductive keratoplasty. A 48-year-old man underwent conductive keratoplasty for low hyperopic astigmatism (manifest refraction OD: +2.25 -0.50 x 77 degrees; OS: +2.50 -0.50 x 105 degrees). Three months postoperatively, UCVA was 20/25 and BSCVA was 20/20 in both eyes; manifest refraction OD: -0.25 -0.75 x 110 degrees; OS: +0.75 -0.75 x 50 degrees. Sixteen months after the operation, regression of refractive outcome was (manifest) OD: +1.75 -1.25 x 90 degrees; OS: +2.50 -0.50 x 85 degrees; UCVA was 20/40 in the right eye and 20/63 in the left eye and BSCVA was 20/20 in both eyes. LASIK was performed for hyperopic regression in the left eye using an automated microkeratome (Alcon SKBM, 130-microm plate; Aesculap-Meditec MEL 70 excimer laser). LASIK was uneventful and no intraoperative or postoperative complications related to the previous conductive keratoplasty procedure or LASIK were observed. Three months after LASIK and 19 months after the initial conductive keratoplasty, the patient's left eye was emmetropic; UCVA was 20/20(-2), BSCVA was 20/20 and manifest refraction was +0.25 -0.25 x 35 degrees. There was a uniform increase in topographical steepening. Visual acuity, refraction and topographic findings remained unchanged at 6 months. Even though our experience is limited, treatment of hyperopia with LASIK in an eye with refractive regression following previous conductive keratoplasty resulted in a predicted refractive outcome, with no complications, and improvement in visual acuity at 6 months follow-up.

'Blue bubble' technique: an ab interno approach for Descemet separation in deep anterior lamellar keratoplasty using trypan blue stained viscoelastic device.

Science.gov (United States)

Livny, Eitan; Bahar, Irit; Hammel, Naama; Nahum, Yoav

2018-04-01

In this study, we examined a novel variant of 'big-bubble' deep anterior lamellar keratoplasty using trypan-blue-stained viscoelastic device for the creation of a pre-descemetic bubble. Ten corneoscleral rims were mounted on an artificial anterior chamber (AC). The AC was filled with air through a limbal paracentesis. A Melles' triangulated spatula was inserted through the paracentesis, with its tip penetrating the AC, was then slightly retracted and pushed into the deep stroma above the roof of the paracentesis. A mixture of trypan blue and viscoelastic device (Healon, Abbott Medical Optics, Abbott Park, Illinois) was injected into this intra-stromal pocket using a 27-G cannula to create a pre-descemetic separation bubble. Bubble type and visualization of dyed viscoelastic device were noted. The method was later employed in three cases. In all 10 corneoscleral rims, the technique successfully created a visible pre-descemetic (type 1) bubble that could be expanded up to the predicted diameter of trephination. Subsequent trephination and the removal of corneal stroma were uneventful. In two out of four clinical cases, a type 1 bubble was created, while in two others, visco-dissection failed and dyed viscoelastic was seen in the AC. The presented technique holds promise of being a relatively easy to perform, predictable and well-controlled alternative for achieving a type 1 bubble during deep anterior lamellar keratoplasty surgery. The trypan-blue-stained viscoelastic device facilitates proper visualization and control of the separation bubble and assists in identifying the penetrance to the separation bubble prior to removal of the stromal cap. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

MMSC-LIKE LIMBAL CELLS COTRANSPLANTATION PROMOTES LOCAL IMMUNOCORRECTION AND CORNEAL GRAFT TRANSPARENT RETENTION IN HIGH RISK KERATOPLASTY

Directory of Open Access Journals (Sweden)

S. A. Borzenok

2014-01-01

Full Text Available Aim was to evaluate clinical results of donor corneal graft survival in high-risk recipients in co-transplantation of preserved allogenic limbal grafts. Materials and methods. Two types of penetrative keratoplasties were carried out in patients with corneal graft opacities and high risk of rejection (n = 69. Co-transplantation of donor cornea and allogenic MMSC-like limbal cells in the form of limbal transplants was carried out in the 1st group (n = 36; in the 2nd group (n = 33 only the cornea was transplanted. Results. Observation of the patients during one year after surgery showed that the rate of transparent cornea engraftment increased in the 1st group (86,1 against 69,7% in the 2nd group. The density of endothelial cells was also higher in the 1st group (85,9 against 76,2% in the 2nd group. At the same time, progressive decreasing of pro-inflammatory cytokines (IL-6, IFNγ, TNFα and increasing of anti-inflammatory cytokines (IL-10, IL-1RA, TGFβ along with higher level of HLA-G5 were revealed in the recipients’ tear fluid in the 1st group in comparison to the 2nd group. Conclusion. Simultaneous transplantation of preserved limbal grafts with corneal graft in high-risk keratoplasty favors the transparent cornea engraftment, obviously, this is due to immunoregulatory activity of the MMSC-like limbal cells. 

Penetrating performance and “self-sharpening” behavior of fine-grained tungsten heavy alloy rod penetrators

Energy Technology Data Exchange (ETDEWEB)

Luo, Rongmei, E-mail: luorm_1999@126.com [School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu (China); College of Equipment Engineering, Shenyang Ligong University, Shenyang 110159, Liaoning (China); Huang, Dewu; Yang, Mingchuan; Tang, Enling; Wang, Meng; He, Liping [College of Equipment Engineering, Shenyang Ligong University, Shenyang 110159, Liaoning (China)

2016-10-15

Rod penetrators with 95W–3.75Ni–1.25Fe fine-grained tungsten heavy alloy (fine-grained 95W) and conventional tungsten heavy alloy rod penetrators with the same chemical composition (conventional 95W) were subjected to ballistic impact to compare their penetration performance. “Self-sharpening” behavior and an average 10.5% increase in penetration depth compared to conventional 95W penetrators. An acute head remained on the fine-grained 95W rod with SEM results revealing many micro-cracks and small debris on surface layer of the rod head. The stress-strain curves collected in the Split Hopkinson Pressure Bar (SHPB) experiment showed that critical failure strain values of the fine-grained 95W were 0.12 and 0.39 at strain rate of 2×10{sup 3} s{sup −1} and 3.9×10{sup 3} s{sup −1}, respectively, approximately 40% and 10% lower than those of the conventional 95W. The dynamic strength values of fine-grained 95W were 2100 MPa and 2520 MPa, respectively, which were 500 MPa and 520 MPa higher than those of the conventional 95W. The relationship among microstructure, mechanical property and “self-sharpening” behavior of fine-grained 95W is discussed in this work.

Opacification of hydrophilic intraocular lenses after Descemet stripping automated endothelial keratoplasty

Directory of Open Access Journals (Sweden)

Morgan-Warren PJ

2015-02-01

Full Text Available Peter J Morgan-Warren, Walter Andreatta, Amit K Patel Department of Ophthalmology, Solihull Hospital, Heart of England NHS Foundation Trust, Birmingham, UK Purpose: Opacification of hydrophilic acrylic intraocular lenses (IOLs is an emerging complication following Descemet stripping automated endothelial keratoplasty (DSAEK. We report six cases and review the current literature.Methods: In this retrospective, noncomparative, observational case series, patients with IOL opacification after previous DSAEK surgery were identified from corneal clinic records. Case notes were reviewed for demographic details, indication for DSAEK, IOL model, incidence of rebubbling, and postoperative course.Results: Six patients developed IOL opacification after DSAEK. All patients had Fuchs’ endothelial dystrophy and had previously received hydrophilic acrylic IOL models. Central anterior IOL opacification was noted in all six cases. Five cases (83% had required rebubbling due to dislocated graft tissue, and one had an early postoperative intraocular pressure (IOP rise. Five cases (83% were managed conservatively, and one case with a failed graft underwent redo DSAEK and IOL exchange.Conclusion: Repeated exposure to intracameral air, raised IOP, and other patient influences may be major etiological factors for IOL opacification after DSAEK. We advise avoiding hydrophilic acrylic IOL models in patients who may require future endothelial keratoplasty. Keywords: IOL, DSAEK, lamellar keratoplasty, endothelial corneal transplantation

[Interlamellar sectoral keratoplasty in the surgical correction of astigmatism].

Science.gov (United States)

Frolov, M A; Beliaev, V S; Dushin, N V; Kravchinina, V V; Barashkov, V I; Gonchar, P A

1996-01-01

A new original method of interlamellar sectorial keratoplasty is proposed for surgical correction of astigmatism. Eleven operations were carried out in 8 patients (11 eyes) with astigmatism of 4 to 7.0 diopters. Vision acuity without correction was 0.6 to 1.0 in 5 patients (7 eyes, 63.6%). In 2 patients (2 eyes, 18.2%) vision acuity without correction was 0.3 to 0.5 diopters, and in 2 more patients (2 eyes, 18.2%) it was from 0.1 to 0.3 diopters, that is, equal to the maximal vision acuity with the optimal correction. The refraction effect stabilized in 3-4 months. The highest refraction effect attained was 7.0 diopters. The patients were followed up for 3 months to 4 years. Clinical analysis of the operations confirmed the efficacy and reliability of the method and stability of refraction. Interlamellar sectorial keratoplasty is recommended for surgical correction of astigmatism.

Keratorefractive Effect of High Intensity Focused Ultrasound Keratoplasty on Rabbit Eyes

Directory of Open Access Journals (Sweden)

Zhiyu Du

2016-01-01

Full Text Available Purpose. To evaluate high intensity focused ultrasound (HIFU as an innovation and noninvasive technique to correct presbyopia by altering corneal curvature in the rabbit eye. Methods. Eighteen enucleated rabbit eyes were treated with a prototype HIFU keratoplasty. According to the therapy power, these eyes were divided three groups: group 1 (1 W, group 2 (2 W, and group 3 (3 W. The change in corneal power was quantified by a Sirius Scheimpflug camera. Light microscopy (LM and transmission electron microscopy (TEM were performed to determine the effect on the corneal stroma. Results. In the treated eyes, the corneal curvature increases from 49.42 ± 0.30 diopters (D and 48.00 ± 1.95 D before procedure to 51.37 ± 1.11 D and 57.00 ± 1.84 D after HIFU keratoplasty application in groups 1 and 3, respectively. The major axis and minor axis of the focal region got longer when the powers of the HIFU got increased; the difference was statistically significant (p<0.05. LM and TEM showed HIFU-induced shrinkage of corneal stromal collagen with little disturbance to the underlying epithelium. Conclusions. We have preliminarily exploited HIFU to establish a new technique for correcting presbyopia. HIFU keratoplasty will be a good application prospect for treating presbyopia.

Hybrid Technique of Lamellar Keratoplasty (DMEK-S

Directory of Open Access Journals (Sweden)

Pavel Studeny

2013-01-01

Full Text Available Purpose: To evaluate the outcomes of the hybrid technique of posterior lamellar keratoplasty (DMEK-S. Materials and Methods: 71 eyes of 55 patients enrolled in a single-center study underwent posterior lamellar keratoplasty with a hybrid lamella DMEK-S implanted using a solution implantation technique, owing to endothelial dysfunction. The outcome measures studied were visual acuity and endothelial cell density. Results: The rate of endothelial cell loss caused by surgery was 43.8%. During followups, we observed the stabilization of postoperative findings, or at minimum a very low rate of corneal endothelial cell loss. The UCDVA and BCDVA dramatically improved postoperatively. The rebubbling rate in our group of patients was 61.9%. We replaced the lamella due to its failure or malfunction in 17 patients (23.9%. Conclusion: In summary, DMEK-S combines the advantages of DSEK/DSAEK and DMEK. The central zone of bare Descemet’s membrane and endothelium allows for very good visual outcomes, and the peripheral rim allows for better manipulation of the lamella during implantation. It is an effective method of treating the endothelial dysfunction of various etiologies, but the high complication rate needs to be addressed before widespread implementation of the technique in the future.

Descemet's membrane endothelial keratoplasty surgery: update on the evidence and hurdles to acceptance.

Science.gov (United States)

Price, Marianne O; Price, Francis W

2013-07-01

Descemet's stripping endothelial keratoplasty (DSEK) is the most popular treatment for endothelial dysfunction, but Descemet's membrane endothelial keratoplasty (DMEK) now provides better vision with lower risk of immunologic rejection. Although DMEK is more challenging, advances in instrumentation and techniques are reducing the learning curve. In contrast to DSEK, which includes posterior donor stroma, DMEK consists merely of donor endothelium and Descemet's membrane, so DMEK does not create a stromal interface and induces significantly less posterior surface aberrations, resulting in better vision. Furthermore, multiple centers report remarkably low (<1%) cumulative probability of immunologic graft rejection episodes through 2 years after DMEK. Initially, the biggest challenges were tissue loss in preparation and ensuring attachment. Subsequent improvements have reduced complication rates to levels experienced with DSEK. DMEK/DSEK hybrids and 'thin' DSEK also can provide better vision than standard DSEK; randomized controlled comparisons with DMEK are needed. DMEK provides an anatomically exact replacement of dysfunctional host endothelium and has set new benchmarks for rejection risk and visual outcomes following endothelial replacement. DMEK is providing new insights into how different corneal layers contribute to immunogenicity and immune tolerance and into the key factors that limit vision after endothelial keratoplasty.

Collagen crosslinking for ectasia following PRK performed in excimer laser-assisted keratoplasty for keratoconus.

Science.gov (United States)

Spadea, Leopoldo

2012-01-01

To report the results of corneal collagen crosslinking (CXL) in a patient with corneal ectasia developed after excimer laser-assisted lamellar keratoplasty for keratoconus and a secondary photorefractive keratectomy (PRK) for residual refractive error. A 33-year-old woman, who had originally been treated for keratoconus in the right eye by excimer laser-assisted lamellar keratoplasty, subsequently had her residual ametropia treated by topographically guided, transepithelial excimer laser PRK. Five years after PRK, the patient developed corneal ectasia showing concomitant visual changes of best spectacle-corrected visual acuity (BSCVA) reduced to 20/33 with a refraction of -6.00 +6.00 × 30. The minimum corneal thickness at the ectasia apex was 406 µm. A treatment of riboflavin-UVA-induced corneal CXL was performed on the right eye. Two years after the CXL treatment, the right eye improved to 20/20 BSCVA with a refraction of plano +1.00 × 50 while exhibiting a clear lamellar graft. Corneal CXL provided safe and effective management of ectasia developed after excimer laser-assisted lamellar keratoplasty and PRK.

Glaucoma after corneal replacement.

Science.gov (United States)

Baltaziak, Monika; Chew, Hall F; Podbielski, Dominik W; Ahmed, Iqbal Ike K

Glaucoma is a well-known complication after corneal transplantation surgery. Traditional corneal transplantation surgery, specifically penetrating keratoplasty, has been slowly replaced by the advent of new corneal transplantation procedures: primarily lamellar keratoplasties. There has also been an emergence of keratoprosthesis implants for eyes that are high risk of failure with penetrating keratoplasty. Consequently, there are different rates of glaucoma, pathogenesis, and potential treatment in the form of medical, laser, or surgical therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

Delayed-Onset Post-Keratoplasty Endophthalmitis Caused by Vancomycin-Resistant Enterococcus faecium

Directory of Open Access Journals (Sweden)

Julio C. Hernandez-Camarena

2012-10-01

Full Text Available Background: Vancomycin-resistant Enterococcus (VRE endophthalmitis after penetrating keratoplasty (PKP is very rare, the management is a challenge due to both the pattern of antibiotic resistance and the aggressive nature of the infectious process. We report the first delayed-onset case of VRE endophthalmitis after PKP. Materials and Methods: Case report of a 51-year-old female with a 7-week history of PKP who arrived at the emergency room with signs and symptoms of endophthalmitis. Initial visual acuity was light perception, and a posterior pole exam was not possible due to the intense vitreous reaction. Mode B ultrasound was used to assess the posterior pole. The patient underwent pars plana vitrectomy and received intravitreous antibiotics. Results: Vitreous stains and cultures were positive for Enterococcus faecium resistant to vancomycin. Donor rim cultures and viral PCR were negative. Treatment was carried out by repeated intravitreal antibiotics and systemic linezolid. Clinical improvement was seen after the second dose of intravitreous antibiotics and systemic linezolid, but visual acuity remained at light perception consistent with the ischemic changes observed in the posterior pole. Conclusion: VRE endophthalmitis might be associated with positive donor rim cultures. Prompt use of systemic linezolid in addition to intravitreous antibiotics is recommendable, but even with prompt treatment, visual prognosis is guarded.

Does lamellar surgery for keratoconus experience the popularity it deserves?

Science.gov (United States)

Wisse, Robert P L; van den Hoven, Célinde M L; Van der Lelij, Allegonda

2014-08-01

To analyse developments in surgical treatment for keratoconus (KC) by assessing rates and types of corneal surgery from 2005 to 2010. The Dutch Transplantation Foundation supplied data on all keratoplasty procedures for KC performed from 2005 to 2010 in the Netherlands. Registration was carried out by the eyebank at allocation and by the surgeon at the time of surgery. The type of surgery was categorized as either a penetrating or a lamellar procedure. Five hundred and seventy-five anonymized records were received, with excellent data completion (99%). Patients undergoing penetrating surgery had on average a lower visual acuity, higher k-readings and were slightly older compared with the lamellar group. A previous corneal hydrops was recorded for 19.1% of patients. Regular penetrating keratoplasty decreased in popularity from 79.7% in 2005 to 43.7% in 2010, due to the increased rate of lamellar surgery (42.5% in 2010) and 'mushroom' penetrating keratoplasty (13.8% in 2010). When hydrops cases were excluded, popularity became equal (47.6% penetrating versus 52.4% lamellar surgery, in 2010). Lamellar surgery is gaining in popularity, although regular penetrating keratoplasty is still the more commonly performed procedure. Only when hydrops cases are excluded do transplant rates become comparable. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

The Results of Corneal Hydrops Treatment in Patients with Down Syndrome

Directory of Open Access Journals (Sweden)

V. K. Surkova

2018-01-01

Full Text Available The article describes the clinical cases of acute keratoconus in three patients with Down syndrome who underwent penetrating  keratoplasty. Acute keratoconus were diagnosed in patients by examination of medical history, biomicroscopy, corneal topography,optical coherence tomography. Acute keratoconus occurs suddenly due to the rupture of Descemet’s membrane in the zone of itsstretching, when chamber moisture seeps into the thickness of the stroma, causing its swelling and perforation. If untreated, theprocess continues for 3–5 months. Most researchers recommend keratoplasty during the cold period of the disease. However, withthe threat of perforation require urgent surgical intervention. There are two effective methods of surgical treatment: epikeratophakiaand penetrating keratoplasty. Patients underwent penetrating keratoplasty. The preference for this method was given in connectionwith the following factors: young age patients (under 40 years, relatively healthy transparent peripheral zone of the cornea, whichwas observed in our patients, genetically determined diseases — Down syndrome, the threat of corneal perforation in the centre, apenchant for rubbing his eye, low vision other eye and the desire to obtain speedy optical effect along with the treatment. All patientsafter penetrating keratoplasty had improvement of visual acuity with observation periods up to 1 year. Due to the relatively highincidence of keratoconus in patients with Down syndrome should focus the attention of ophthalmologists. Thus, difficulties in thediagnosis of ophthalmic pathology in patients with concomitant Down syndrome can cause errors in verification of diagnosis and hencewrong treatment selection. In case of hydrops of the cornea penetrating keratoplasty is the choice treatment and contributes to the preservation of the eye and visual functions.

Keratomycosis caused by Acremonium Recifei, treated with keratoplasty, Miconazole and Ketoconazole

NARCIS (Netherlands)

H.J. Simonsz (Huib)

1983-01-01

textabstractA patient is discussed who developed a fungal corneal ulcer due to Acremonium (Cephalosporium) Recifei after a piece of a coconut flew into his eye while he was cracking it. Treatment consisted of keratoplasty, Miconazole as ointment and intravenously, and Ketaconazole orally. Diagnosis

Donor disc attachment assessment with intraoperative spectral optical coherence tomography during descemet stripping automated endothelial keratoplasty

Directory of Open Access Journals (Sweden)

Edward Wylegala

2013-01-01

Full Text Available Optical coherence tomography has already been proven to be useful for pre- and post-surgical anterior eye segment assessment, especially in lamellar keratoplasty procedures. There is no evidence for intraoperative usefulness of optical coherence tomography (OCT. We present a case report of the intraoperative donor disc attachment assessment with spectral-domain optical coherence tomography in case of Descemet stripping automated endothelial keratoplasty (DSAEK surgery combined with corneal incisions. The effectiveness of the performed corneal stab incisions was visualized directly by OCT scan analysis. OCT assisted DSAEK allows the assessment of the accuracy of the Descemet stripping and donor disc attachment.

Crystal growth vs. conventional acid etching: A comparative evaluation of etch patterns, penetration depths, and bond strengths

Directory of Open Access Journals (Sweden)

Devanna Raghu

2008-01-01

Full Text Available The present study was undertaken to investigate the effect on enamel surface, penetration depth, and bond strength produced by 37% phosphoric acid and 20% sulfated polyacrylic acid as etching agents for direct bonding. Eighty teeth were used to study the efficacy of the etching agents on the enamel surface, penetration depth, and tensile bond strength. It was determined from the present study that a 30 sec application of 20% sulfated polyacrylic acid produced comparable etching topography with that of 37% phosphoric acid applied for 30 sec. The 37% phosphoric acid dissolves enamel to a greater extent than does the 20% sulfated polyacrylic acid. Instron Universal testing machine was used to evaluate the bond strengths of the two etching agents. Twenty percent sulfated polyacrylic acid provided adequate tensile bond strength. It was ascertained that crystal growth can be an alternative to conventional phosphoric acid etching as it dissolves lesser enamel and provides adequate tensile bond strength.

[Endothelial keratoplasty: Descemet stripping (DSEK) using TAN EndoGlide™ device: case series].

Science.gov (United States)

Pazos, Henrique Santiago Baltar; Pazos, Paula Fernanda Morais Ramalho Baltar; Nogueira Filho, Pedro Antônio; Grisolia, Ana Beatriz Diniz; Silva, André Berger Emiliano; Gomes, José Álvaro Pereira

2011-01-01

To report the results of Descemet stripping endothelial keratoplasty (DSEK) using the TAN EndoGlideTM device to facilitate the insertion of the endothelial membrane. Prospective clinical study that included nine patients presenting corneal edema secondary to endothelial dysfunction. Best corrected visual acuity, refraction, central corneal thickness, endothelial cell density and complications were analyzed after a six-month follow-up. There was a significant improvement in the corneal edema and visual acuity in 7 patients (77.78%). The best corrected visual acuity ranged between 20/40 and 20/200. The average density of endothelial cells in six months varied between 1,305 cells/mm² and 2,346 cells/mm² with an average loss of 33.14% cells. Detachment of part of the graft was observed in one eye (11.11%) and primary failure of the endothelial transplantation occurred in 2 eyes (22.22%). The device TAN EndoGlideTM facilitates the introduction of the graft in Descemet stripping endothelial keratoplasty.

Sequential selective same-day suture removal in the management of post-keratoplasty astigmatism.

Science.gov (United States)

Fares, U; Mokashi, A A; Elalfy, M S; Dua, H S

2013-09-01

In a previous study, we proposed that corneal topography performed 30-40 min after the initial suture removal can identify the next set of sutures requiring removal, for the treatment of post-keratoplasty astigmatism. The aim of this study was to evaluate the effect of removing subsequent sets of sutures at the same sitting. 10/0 nylon interrupted sutures were placed, to secure the graft-host junction, at the time of keratoplasty. Topography was performed using Pentacam (Oculus) before suture removal. The sutures to be removed in the steep semi-meridians were identified and removed at the slit-lamp biomicroscope. Topography was repeated 30-40 min post suture removal, the new steep semi-meridians determined, and the next set of sutures to be removed were identified and removed accordingly. Topography was repeated 4-6 weeks later and the magnitude of topographic astigmatism was recorded. A paired-samples t-test was used to evaluate the impact of selective suture removal on reducing the magnitude of topographic and refractive astigmatism. Twenty eyes of 20 patients underwent sequential selective same-day suture removal (SSSS) after corneal transplantation. This study showed that the topographic astigmatism decreased by about 46.7% (3.68 D) and the refractive astigmatism decreased by about 37.7% (2.61 D) following SSSS. Vector calculations also show a significant reduction of both topographic and refractive astigmatism (P<0.001). SSSS may help patients to achieve satisfactory vision more quickly and reduce the number of follow-up visits required post keratoplasty.

Intraocular pressure measurements after conductive keratoplasty.

Science.gov (United States)

Kymionis, George D; Naoumidi, Tatiana L; Aslanides, Ioannis M; Kumar, Vinod; Astyrakakis, Nikolaos I; Tsilimbaris, Miltiadis; Pallikaris, Ioannis G

2005-01-01

To determine the possible impact of conductive keratoplasty (CK) on intraocular pressure (IOP) measurements. A prospective, single-center, noncomparative interventional case series was performed. Baseline and postoperative IOPs were measured by Goldmann applanation tonometry in 32 eyes of 18 patients who underwent CK for hyperopia correction. Mean follow-up was 11.9 months (range: 8 to 18 months). After CK, a statistically significant decrease in the measured IOP was observed (before CK: 14.22+/-1.64 vs after CK: 12.66+/-2.21, P<.001). The change in IOP readings postoperatively was not correlated with age, sex, keratometric readings, or attempted correction. Despite the limitations due to the small number of patients enrolled in this study, the applanation tonometer appears to underestimate the true IOP after CK.

Non-Descemet’s stripping automated endothelial keratoplasty for bullous keratopathy secondary to iridoschisis

Directory of Open Access Journals (Sweden)

Minezaki T

2013-07-01

Full Text Available Teruumi Minezaki, Takaaki Hattori, Hayate Nakagawa, Shigeto Kumakura, Hiroshi GotoDepartment of Ophthalmology, Tokyo Medical University, Shinjukuku, Tokyo, JapanPurpose: To report a case of bullous keratopathy secondary to iridoschisis treated by non-Descemet's stripping automated endothelial keratoplasty (nDSAEK.Case report: A 79-year-old woman was referred to our hospital with loss of vision in the left eye. Slit lamp examination of her left eye showed a shallow anterior chamber with cataract and schisis in the inferior quadrant of iris stroma. Bullous keratopathy secondary to iridoschisis was diagnosed. Cataract surgery with iridectomy succeeded to deepen the anterior chamber and remove the floating iris leaf, although corneal edema remained. Four days later, nDSAEK was performed, which resolved corneal edema and restored visual acuity.Conclusion: The two-step surgery of cataract surgery plus iridectomy followed by nDSAEK may be an effective strategy for treating bullous keratopathy secondary to iridoschisis.Keywords: iridoschisis, bullous keratopathy, non-Descemet's stripping automated endothelial keratoplasty

Challenges in pediatric endothelial keratoplasty

Directory of Open Access Journals (Sweden)

Vikas Mittal

2014-01-01

Full Text Available We performed endothelial keratoplasty (EK in three eyes of two siblings (2.5 years, male and 3.5 years, female with congenital hereditary endothelial dystrophy (CHED and report the intraoperative and postoperative difficulties. Repeated iris prolapse, apprehension of crystalline lens touch due to positive vitreous pressure, and need for frequent air injections to attach the graft were intraoperative challenges in all three eyes. These were addressed by use of Sheet′s glide instead of Busin′s glide during graft insertion and suturing of main and side ports before air injection. One eye had graft dislocation on second postoperative day due to eye rubbing by the child. Graft was repositioned with air and a venting incision was created. Postoperative examination required repeated general anesthesia. Corneal edema resolved completely in all three eyes. Present case series highlights the possible intraoperative and postoperative challenges and their solutions in pediatric EK for CHED.

Quality of vision in patients with fuchs endothelial dystrophy and after descemet stripping endothelial keratoplasty

NARCIS (Netherlands)

van der Meulen, Ivanka J. E.; Patel, Sanjay V.; Lapid-Gortzak, Ruth; Nieuwendaal, Carla P.; McLaren, Jay W.; van den Berg, Thomas J. T. P.

2011-01-01

To evaluate the quality of vision (visual acuity and straylight) in patients with Fuchs dystrophy and the improvement in visual quality after Descemet stripping endothelial keratoplasty (DSEK). There was an observational case series (Amsterdam group) and a prospective interventional case series

Descemet membrane endothelial keratoplasty (DMEK) early stage graft failure in eyes with preexisting glaucoma.

Science.gov (United States)

Treder, Maximilian; Alnawaiseh, Maged; Eter, Nicole

2017-07-01

To evaluate the effect of a preexisting glaucoma on the early postoperative outcome of a descemet membrane endothelial keratoplasty (DMEK). All patients who underwent DMEK surgery at the Department of Ophthalmology of the University of Muenster with a follow-up of at least 3 months (90d) were included in this study. The best corrected distance visual acuity (BCDVA), the intraocular pressure (IOD), the rate of re-keratoplasty and the rebubbling rate were inter alia recorded. The results of patients with (group 1) and without a preexisting glaucoma (group 2) were compared. 74 eyes of 59 patients with a mean follow-up of 152 ± 70 days were included. 65 eyes were in group 1 and 9 eyes in group 2. The BCDVA significantly improved in both groups after surgery (p glaucoma compared to patients with a preexisting glaucoma. In the early stage outcome of DMEK no significant impact of a preexisting glaucoma was found.

[Interlamellar circular keratoplasty for correction of high myopia].

Science.gov (United States)

Beliaev, V S; Dushin, N V; Gonchar, P A; Frolov, M A; Barashkov, V I; Kravchinina, V V; Balikoev, T M

1995-01-01

A new method is proposed for the correction of high myopia: Interlamellar circular keratoplasty. This method has been used in 15 patients (17 eyes) aged 18 to 54 with 9 to 17 diopters myopia. Vision acuity attained was at least 0.5 in 10 (60.3%) patients; in 7 (35.2%) patients vision acuity was 0.3 without correction, that is, was equal to the maximal vision acuity with the optimal correction. The highest refraction effect was 15.0 diopters. The patients were followed up for 3 months to 16 years. The proposed method for the correction of high myopia is highly effective, simple, and is recommended for clinical practice.

Development of coring, consolidating, subterrene penetrators

International Nuclear Information System (INIS)

Murphy, H.D.; Neudecker, J.W.; Cort, G.E.; Turner, W.C.; McFarland, R.D.; Griggs, J.E.

1976-02-01

Coring penetrators offer two advantages over full face-melting penetrators, i.e., formation of larger boreholes with no increase in power and the production of glass-lined, structurally undisturbed cores which can be recovered with conventional core-retrieval systems. These cores are of significant value in geological exploratory drilling programs. The initial design details and fabrication features of a 114-mm-diam coring penetrator are discussed; significant factors for design optimization are also presented. Results of laboratory testing are reported and compared with performance predictions, and an initial field trial is described

Novel spatula and dissector for safer deep anterior lamellar keratoplasty

Directory of Open Access Journals (Sweden)

Gustavo ,2,3 Bonfadini

2014-10-01

Full Text Available Objective: We describe a novel spatula and dissector to facilitate the big-bubble technique in deep anterior lamellar keratoplasty (DALK. Methods: A 29-year-old man who was diagnosed with bilateral keratoconus underwent deep anterior lamellar keratoplasty (DALK. After 350μm partial thickness incision of the recipient cornea, the Bonfadini dissector was inserted at the deepest point in the peripheral incision and could be advanced to the center of the cornea safely because of its "semi-sharp" tip. After achieving the big-bubble (BB separation of Descemet membrane (DM from the overlying stroma, the anterior stromal disc was removed. Viscoelastic material was placed on the stromal bed to prevent uncontrolled collapse and perforation of DM during the paracentesis blade incision into the BB. We could detect the safe opening of the BB using the Bonfadini dissector by the leakage of air bubbles into the viscoelastic material. After injecting viscoelastic material into the BB space, we inserted the Bonfadini spatula into the bigbubble safely because of its curved profile and blunt edges. The groove along the length of the Bonfadini spatula enables safe and efficient incision or the residual stromal tissue using the pointed end of a sharp blade while protecting the underlying DM. After removal of posterior stroma, the donor button was sutured with 16 interrupted 10-0 nylon sutures. Results: This technique and the use of the Bonfadini spatula and dissector facilitate exposure of Descemet membrane. Conclusion: The smooth Bonfadini DALK spatula and dissector facilitate safe and efficient completion of DALK surgery.

Analysis of the Noneroding Penetration of Tungsten Alloy Long Rods into Aluminum Targets

National Research Council Canada - National Science Library

Segletes, Steven

2003-01-01

.... the eroding-penetration regimes. Conventional one-dimensional penetration analysis reveals that the noneroding datum is wholly consistent with the notion of treating the rod as if it penetrated in a rigid-body fashion, possessing...

Explore the full thick layer of corneal transplantation in the treatment of pseudomonas aeruginosa corneal ulcer infection

Directory of Open Access Journals (Sweden)

Xin Wang

2015-02-01

Full Text Available AIM: To explore the feasibility, safety and effect of the full-thickness lamellar keratoplasty for the treatment of pseudomonas aeruginosa corneal ulcer. METHODS: Based on a retrospective non-controlled study, 25 patients were given the full-thickness lamellar keratoplasty for clinical diagnosis of pseudomonas aeruginosa infection and corneal ulcer medication conventional anti-gram-negative bacteria. Routine follow-up were carried out at postoperative 1wk; 1, 3, 6, 12, 18mo to observe the situation of corneal epithelial healing, recurrent infection, immune rejection, graft transparency and best corrected visual acuity, etc. At the 6 and 12mo postoperative, corneal endothelial cell density was reexamined.RESULTS: No patients because of Descemet's membrane rupture underwent penetrating keratoplasty surgery: One only in cases of bacterial infection after 1mo, once again did not cultivate a culture of bacteria pseudomonas aeruginosa, and the remaining 24 cases average follow-up 14±6mo, corneal graft were transparent, the cure rate was 96%. At the sixth month after surgery, there were 16 cases of eye surgery best corrected visual acuity ≥4.5, of which 3 cases ≥4.8. At the sixth month after surgery, the average corneal endothelial cell density 2 425±278/mm2; At 12mo postoperatively, it was 2 257± 326/mm2.CONCLUSION: Full-thickness lamellar keratoplasty is an effective method of pseudomonas aeruginosa infection in the treatment of corneal ulcers, corneal drying material glycerol can be achieved by visual effects.

[Special penetration needling for refractory peripheral facial paralysis].

Science.gov (United States)

Cao, Rongjuan; Qiu, Xiaohu; Xie, Xiaokun

2018-03-12

To observe the clinical effect difference between special penetration needling and conventional penetration needling for the refractory peripheral facial paralysis. A total of 97 patients with intractable facial paralysis were randomized into an observation group (49 cases and 2 dropping) and a control group (48 cases and 4 dropping). In the observation group, special penetration needling at an angle about 45° between the penetration needle and paralysis muscle bundle was used, Yangbai (GB 14) through Touwei (ST 8), Yangbai (GB 14) through Shangxing (GV 23), Sizhukong (TE 23) through Yuyao (EX-HN 4), Qianzhen (Extra) through Yingxiang (LI 20), mutual penetration between Yingxiang (LI 20) and Jiache (ST 6). Conventional penetration needling was applied in the control group, Yangbai (GB 14) through Yuyao (EX-HN 4), Cuanzhu (BL 2) through Yuyao (EX-HN 4), mutual penetration between Dicang (ST 4) and Jiache (ST 6), Qianzheng (Extra) through Dicang (ST 4), Sibai (ST 2) through Yingxiang (LI 20). Three groups of electroacupuncture (discontinuous wave, 1 Hz) with tolerance were connected respectively in the two groups, Yangbai (GB 14) and Sizhukong (TE 23), Yangbai (GB 14) and Qianzheng (Extra), Yingxiang (LI 20) and Jiache (ST 6) in the observation group, Yangbai (GB 14) and Cuanzhu (BL 2), Dicang (ST 4) and Jiache (ST 6), Qianzheng (Extra) and Sibai (ST 2) in the control group. TDP was applied in the two groups at the affected Yifeng (TE 17), Jiache (ST 6) and Qianzheng (Extra), which were around the ear. Perpendicular insertion was used at Yifeng (TE 17) at the affected side and Hegu (LI 4) at the healthy side and bilateral Zusanli (ST 36). The needles were retained for 30 min. The treatment was given for 3 courses, once a day and 10 days as a course, 5 days at the interval. House-Brackmann (H-B) facial nerve grading score was recorded before and after treatment. The clinical effects were compared. The H-B scores after treatment in the two groups were higher than

Simultaneous topography-guided PRK followed by corneal collagen cross-linking after lamellar keratoplasty for keratoconus

Directory of Open Access Journals (Sweden)

Spadea L

2012-11-01

Full Text Available Leopoldo Spadea,1 Marino Paroli21University of L’Aquila, Department of Biotechnological and Applied Clinical Sciences, Eye Clinic, L’Aquila, 2La Sapienza University, Department of Biotechnology and Medical-Surgical Sciences, Latina, ItalyBackground: The purpose of this paper is to report the results of using combined treatment of customized excimer laser-assisted photorefractive keratectomy (PRK and prophylactic corneal collagen crosslinking (CXL for residual refractive error in a group of patients who had previously undergone lamellar keratoplasty for keratoconus.Methods: The study included 14 eyes from 14 patients who had originally been treated for keratoconus in one eye by excimer laser-assisted lamellar keratoplasty (ELLK, and subsequently presented with residual ametropia (-6.11 D ± 2.48, range -2.50 to -9.50. After a mean 40.1 ± 12.4 months since ELLK they underwent combined simultaneous corneal regularization treatment with topographically guided transepithelial excimer laser PRK (central corneal regularization and corneal CXL induced by riboflavin-ultraviolet A.Results: After a mean 15 ± 6.5 (range 6–24 months, all eyes gained at least one Snellen line of uncorrected distance visual acuity (range 1–10. No patient lost lines of corrected distance visual acuity, and four patients gained three lines of corrected distance visual acuity. Mean manifest refractive spherical equivalent was -0.79 ± 2.09 (range +1 to -3.0 D, and topographic keratometric astigmatism was 5.02 ± 2.93 (range 0.8–8.9 D. All the corneas remained clear (haze < 1.Conclusion: The combination of customized PRK and corneal CXL provided safe and effective results in the management of corneal regularization for refractive purposes after ELLK for keratoconus.Keywords: corneal collagen crosslinking, excimer laser-assisted lamellar keratoplasty, photorefractive keratectomy

Development prospects of keratoplasty in Moscow

Directory of Open Access Journals (Sweden)

E. M. Kildyushov

2013-01-01

Full Text Available A retrospective analysis of the statistical data for the years 2010‑2012 on mortality and the donor selection of the Bureau of Forensic Pathology of Moscow, Department of Forensic Pathology of Pirogov N. I. Russian National Research Medical University and ILab Eye Bank in order to determine the possible number of keratoplastic surgeries. The results of statistical data analysis testify to the fact that the number of available donor material is not sufficient to meet the needs for keratoplastic material and it is necessary to create eye banks, which would have provided this need. It is necessary to create eye banks, that possess a clear logistics chain of intake donor tissue, preliminary assessment of the donor tissue, laboratory diagnostics of the donor’s blood and delivery of tissue to the Bank. Theeye bank should not only produce preserved material for keratoplasty, but also carry out full morpho-functional assessment of material and its subsequent delivery to consumers in health facilities.

Preparation and thickness profile of endothelial keratoplasty lenticules from donated whole eyes with previous photorefractive keratectomy

Directory of Open Access Journals (Sweden)

Mozhgan Rezaei Kanavi

2017-01-01

Conclusion: PRK donor whole eyes are potential sources for preparation of microkeratome-assisted thin endothelial keratoplasty lenticules with a high endothelial cell count. Although an asymmetric and significant increase in thickness was present at the peripheral cornea, neither attachment nor clarity of transplanted lenticules was affected by variations in thickness of precut corneas.

Young donor-graft assisted endothelial keratoplasty (PDEK/DMEK) with epithelial debridement for chronic pseudophakic bullous keratopathy.

Science.gov (United States)

Agarwal, Amar; Narang, Priya; Kumar, Dhivya A; Agarwal, Ashvin

2017-10-01

The aim of this study was to describe the applicability and report visual outcomes for the treatment of subepithelial fibrosis and anterior stromal scarring in cases of chronic pseudophakic bullous keratopathy (PBK) with epithelial debridement and endothelial keratoplasty (EK) (pre-Descemet endothelial keratoplasty [PDEK]; Descemet membrane endothelial keratoplasty [(DMEK]) using young donor tissue. Prospective, single-centre, interventional study. 6 cases with chronic PBK (> 1 year duration). Case 1 underwent PDEK with glued intraocular lens (IOL) as a single-stage procedure, whereas cases 2 and 3 underwent glued IOL followed by DMEK and PDEK, respectively, as a second-stage procedure. Cases 4 and 6 underwent PDEK, whereas case 5 underwent DMEK. Epithelial debridement was performed in all cases at the time of EK, and young donor grafts were used. The main outcome measures were best spectacle-corrected visual acuity, clearance of corneal scar and haze, central corneal thickness (CCT), specular microscopy, and endothelial cell count (ECC). Postoperatively, all cases demonstrated significant improvement in visual acuity. The mean value of depth of subepithelial haze was 121±71.7 µm and 25.3 ± 19.8 µm in the preoperative and postoperative periods, respectively (p = 0.028). At the 1-month follow-up, the mean preoperative CCT of 676 ± 92.7 µm was reduced to 534.6 ± 21.1µm. At the 6-month follow-up, the mean ECC loss resulting from the procedure was 36.5 ± 10.4%. EK with epithelial debridement performed for the treatment of chronic PBK resulted in significantly improved visual acuity to a functional level, with the clearance of subepithelial fibrosis and anterior stromal scar, in most patients. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

A biodegradable, sustained-released, prednisolone acetate microfilm drug delivery system effectively prolongs corneal allograft survival in the rat keratoplasty model.

Directory of Open Access Journals (Sweden)

Yu-Chi Liu

Full Text Available Frequent and long-term use of topical corticosteroids after corneal transplantation is necessary to prevent graft rejection. However, it relies heavily on patient compliance, and sustained therapeutic drug levels are often not achieved with administration of topical eye drops. A biodegradable drug delivery system with a controlled and sustained drug release may circumvent these limitations. In this study, we investigated the efficacy of a prednisolone acetate (PA-loaded poly (d,l-lactide-co-ε-caprolactone (PLC microfilm drug delivery system on promoting the survival of allogeneic grafts after penetrating keratoplasty (PK using a rat model. The drug release profiles of the microfilms were characterized (group 1. Subsequently, forty-eight PK were performed in four experimental groups: syngeneic control grafts (group 2, allogeneic control grafts (group 3, allogeneic grafts with subconjunctivally-implanted PA microfilm (group 4, and allogeneic grafts with PA eye drops (group 5; n = 12 in each. PA-loaded microfilm achieved a sustained and steady release at a rate of 0.006-0.009 mg/day, with a consistent aqueous drug concentration of 207-209 ng/ml. The mean survival days was >28 days in group 2, 9.9±0.8 days in group 3, 26.8±2.7 days in group 4, and 26.4±3.4 days in group 5 (P = 0.023 and P = 0.027 compared with group 3. Statistically significant decrease in CD4+, CD163+, CD 25+, and CD54+ cell infiltration was observed in group 4 and group 5 compared with group 3 (P<0.001. There was no significant difference in the mean survival and immunohistochemical analysis between group 4 and group 5. These results showed that sustained PA-loaded microfilm effectively prolongs corneal allograft survival. It is as effective as conventional PA eye drops, providing a promising clinically applicable alternative for patients undergoing corneal transplantation.

Fitting an MSD (mini scleral design) rigid contact lens in advanced keratoconus with INTACS.

Science.gov (United States)

Dalton, Kristine; Sorbara, Luigina

2011-12-01

Keratoconus is a bilateral degenerative disease characterized by a non-inflammatory, progressive central corneal ectasia (typically asymmetric) and decreased vision. In its early stages it may be managed with spectacles and soft contact lenses but more commonly it is managed with rigid contact lenses. In advanced stages, when contact lenses can no longer be fit, have become intolerable, or corneal damage is severe, a penetrating keratoplasty is commonly performed. Alternative surgical techniques, such as the use of intra-stromal corneal ring segments (INTACS) have been developed to try and improve the fit of rigid contact lenses in keratoconic patients and avoid penetrating keratoplasties. This case report follows through the fitting of rigid contact lenses in an advanced keratoconic cornea after an INTACS procedure and discusses clinical findings, treatment options, and the use of mini-scleral and scleral lens designs as they relate to the challenges encountered in managing such a patient. Mini-scleral and scleral lenses are relatively easy to fit, and can be of benefit to many patients, including advanced keratoconic patients, post-INTAC patients and post-penetrating keratoplasty patients. 2011 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Successful treatment of Fusarium keratitis after photo refractive keratectomy

Directory of Open Access Journals (Sweden)

Gian Maria Cavallini

2013-01-01

Full Text Available A 39-year-old woman presented to our hospital with a history of photorefractive keratectomy (PRK, performed two weeks prior; slit-lamp examination revealed diffuse conjunctival congestion, corneal ulcer and stromal infiltration. After 5 days of antifungal and antibacteric treatment, the infiltrate progressively increased so that a therapeutic penetrating keratoplasty was necessary. The microbiological analyses revealed the presence of fungal filaments. Twenty days after surgery the patient had recurrent fungal infiltrate in the donor cornea with wound dehiscence. We performed a second penetrating keratoplasty. With the matrix-assisted-laser-desorption-ionization-time-of-flight analysis (MALDI-TOF we identified a Fusarium solani.Intravenous amphothericine B, a combination of intracameral and intrastromal voriconazole and intracameral amphotericine B were administered. After 6 months from the last surgery the infection was eradicated. The management of fungal keratitis after PRK depends on many factors: In our experience, a prompt keratoplasty and the use of intracameral antifungal medication proved to be very effective.

Opportunities for high wind energy penetration

DEFF Research Database (Denmark)

Tande, J.O.; Hansen, J.C.

1997-01-01

Wind power is today a mature technology, which at windy locations, is economically competitive to conventional power generation technologies. This and growing global environmental concerns have led governments to encourage and plan for wind energy development, a typical aim being 10% of electricity...... consumption. The successful operation of the three major power systems of Cape Verde, with a total wind energy penetration of about 15% since December 1994, demonstrates that power systems can be operated with high penetration of wind energy by adding simple control and monitoring systems only. Thorough...... analyses conclude that expanding to even above 15% wind energy penetration in the Cape Verde power systems is economical. Worldwide, numerous locations with favorable wind conditions and power systems similar to the Capeverdean provide good opportunities for installing wind farms and achieving high wind...

Healed corneal ulcer with keloid formation.

Science.gov (United States)

Alkatan, Hind M; Al-Arfaj, Khalid M; Hantera, Mohammed; Al-Kharashi, Soliman

2012-04-01

We are reporting a 34-year-old Arabic white female patient who presented with a white mass covering her left cornea following multiple ocular surgeries and healed corneal ulcer. The lesion obscured further view of the iris, pupil and lens. The patient underwent penetrating keratoplasty and the histopathologic study of the left corneal button showed epithelial hyperplasia, absent Bowman's layer and subepithelial fibrovascular proliferation. The histopathologic appearance was suggestive of a corneal keloid which was supported by further ultrastructural study. The corneal graft remained clear 6 months after surgery and the patient was satisfied with the visual outcome. Penetrating keratoplasty may be an effective surgical option for corneal keloids in young adult patients.

Evaluation of penetration and scattering components in conventional pinhole SPECT: phantom studies using Monte Carlo simulation

International Nuclear Information System (INIS)

Deloar, Hossain M; Watabe, Hiroshi; Aoi, Toshiyuki; Iida, Hidehiro

2003-01-01

In quantitative pinhole SPECT, photon penetration through the collimator edges (penetration), and photon scattering by the object (object scatter) and collimator (collimator scatter) have not been investigated rigorously. Monte Carlo simulation was used to evaluate these three physical processes for different tungsten knife-edge pinhole collimators using uniform, hotspot and donut phantoms filled with 201 Tl, 99m Tc, 123 I and 131 I solutions. For the hotspot phantom, the penetration levels with respect to total counts for a 1 mm pinhole aperture were 78%, 28% and 23% for 131 I, 123 I and 99m Tc, respectively. For a 2 mm aperture, these values were 65% for 131 I, 16% for 123 I and 12% for 99m Tc. For all pinholes, 201 Tl penetration was less than 4%. The evaluated scatter (from object and collimator) with a hotspot phantom for the 1 mm pinhole was 24%, 16%, 18% and 13% for 201 Tl, 99m Tc, 123 I and 131 I, respectively. Summation of the object and collimator scatter for the uniform phantom was approximately 20% higher than that for the hotspot phantom. Significant counts due to penetration and object and collimator scatter in the reconstructed image were observed inside the core of the donut phantom. The collimator scatter can be neglected for all isotopes used in this study except for 131 I. Object scatter correction for all radionuclides used in this study is necessary and correction for the penetration contribution is necessary for all radionuclides but 201 Tl

Changing indications and techniques for corneal transplantations at a tertiary referral center in Turkey, from 1995 to 2014

Directory of Open Access Journals (Sweden)

Altay Y

2016-06-01

Full Text Available Yesim Altay, Ayse Burcu, Gozde Aksoy, Evin Singar Ozdemir, Firdevs Ornek Department of Ophthalmology, Ankara Training and Research Hospital, Ankara, Turkey Background: Indications for corneal transplantation in developed and developing nations differ according to the different spectrum of corneal disease in each country. Objective: The purpose of this study is to analyze the changing indications and surgical techniques for corneal transplantation over the past 20 years at a tertiary referral center in Turkey. Methods: We retrospectively reviewed the records of patients who underwent keratoplasty from January 1995 to December 2014 (between 1995 and 2004, period 1, and between 2005 and 2014, period 2. Patients’ demographic data, indications for corneal transplantation, and the type of surgery were recorded. Results: The number of keratoplasties performed ranged from 548 in period 1 to 782 in period 2. Between 1995 and 2004, the leading indications were keratoconus (34.1%, bullous keratopathy (17%, and non-herpetic corneal scar (13.3%, and between 2005 and 2014, they were keratoconus (33.8%, corneal stromal dystrophy (14.2%, and bullous keratopathy (12.7%. All the keratoplasties performed in the 1995–2004 period were penetrating keratoplasty (PKP. During the period 2005–2014, PKP accounted for 93%, automated lamellar keratoplasty 5.8%, and deep anterior lamellar keratoplasty 1.2% of all corneal transplantations. Conclusion: Keratoconus was the leading indication for keratoplasty in both periods. In the 2005–2014 period, corneal stromal dystrophy increased significantly. All the keratoplasties performed in period 1 and 93% of all keratoplasties performed in period 2 were PKP. Keywords: corneal transplantation, indication, keratoconus, keratoplasty technique, pene­trating keratoplasty

The penetration of aerosols through fine capillaries

International Nuclear Information System (INIS)

Mitchell, J.P.; Edwards, R.T.; Ball, M.H.E.

1989-10-01

A novel experimental technique has been developed to study the penetration of aerosol particles ranging from about 1 to 15 μm aerodynamic diameter through capillaries varying from 20 to 80 μm bore and from 10 to 50 mm in length. When the driving pressure was 100 kPa, the penetration of the airborne particles was considerably smaller than expected from a simple comparison of particle diameter with the bore of the capillary. Particle size distributions determined after penetration through the capillaries were in almost all cases similar to the particle size distribution of the aerosol at the capillary entrance. This lack of size-selectivity can be explained in terms of the capillary behaving as a conventional suction-based sampler from a near still (calm) air environment. The resulting particle penetration data are important in assessing the potential for the leakage of aerosols through seals in containers used to transport radioactive materials. (author)

Retention and penetration of a conventional resin-based sealant and a photochromatic flowable composite resin placed on occlusal pits and fissures

Directory of Open Access Journals (Sweden)

Aguilar F

2007-01-01

Full Text Available This study compares the retention and penetration of a conventional resin-based sealant (Fluroshield and a photochromatic flowable composite resin (Tetric Flow Chroma placed on occlusal pits and fissures and submitted to thermal or chemical cycling regimens. Penetration assessment - ten premolars were sealed with each material, isolated (except for the sealed surface and immersed in 0.2% Rhodamine B. The teeth were serially sectioned in a mesiodistal direction. The images of the sections were digitized and analyzed (ImageLab. The distance between the most superficial and the deepest points on the occlusal central groove was calculated to determine the groove′s total depth. The length of the central groove filled with the sealant was divided by its total depth to obtain the percentage of sealing of the occlusal groove. Retention assessment - 30 premolars were sealed, their occlusal surfaces were photographed and the area occupied by the sealing materials was demarcated (ImageLab. The teeth were submitted to different treatments: thermocycled, stored in artificial saliva and immersed in acetic acid and saliva (10 cycles/day protocol for 30 days. New photographs were taken to assess the final area occupied by the materials. The difference between the final and initial area was calculated to obtain the material loss. The data was analyzed (two-way anova and Tukey′s test P < 0.05. Both materials presented similar penetration of the occlusal central groove. After thermal and chemical cycling, the materials did not differ with respect to retention, except for immersion in acetic acid. In this case, Tetric Flow Chroma presented greater retention than Fluoroshield.

Comparison of synthetic glues and 10-0 nylon in rabbit lamellar keratoplasty.

Science.gov (United States)

Cho, Soon Young; Kim, Man Soo; Oh, Su Ja; Chung, Sung Kun

2013-09-01

To evaluate changes in mean keratometry and to compare wound repair with corneal lamellar grafts in rabbit eyes using human synthetic tissue adhesives and 10-0 nylon. Corneal grafts were made using a 6.0-mm-diameter trephine and blades in the eyes of 15 New Zealand white rabbits. Human fibrin tissue adhesive (Tisseel) was used in group 1, human fibrin tissue adhesive (Beriplast P) was used in group 2, polyethylene glycol adhesive (Coseal) was used in group 3, and 8 bite sutures with 10-0 nylon were used in group 4 (control) for lamellar keratoplasty. Four bite sutures were made with 10-0 nylon in groups 1, 2, and 3. Slit-lamp microscopy and keratometry were performed at 3 days and 1, 2, and 4 weeks after the surgery. Histopathologic and electromicroscopic examinations were performed 4 weeks after the surgery. No inflammation or corneal toxicity was seen in groups 1 and 2. Histologically, a few inflammatory cells were seen in groups 3 and 4. Groups 1, 2, and 3 showed no statistically significant changes in mean keratometry at 4 weeks postoperatively compared with preoperative mean keratometry (Wilcoxon signed-rank test, P = 0.178, 0.208, and 0.889, respectively). The control group showed significant changes in mean keratometry at 4 weeks postoperatively (Wilcoxon signed-rank test, P = 0.018). Human fibrin tissue adhesives were well tolerated in rabbit eyes, with no apparent corneal toxicity. Polyethylene glycol adhesive showed more inflammation and insufficient wound repair compared with human fibrin tissue adhesives. Therefore, human fibrin tissue adhesives can be used as an alternative to sutures in lamellar keratoplasty.

Fungal keratitis secondary to Scedosporium apiospermum infection and successful treatment with surgical and medical intervention.

Science.gov (United States)

Kepez Yildiz, Burcin; Hasanreisoglu, Murat; Aktas, Zeynep; Aksu, Gulsah; Kocak, Burcak Comert; Akata, Fikret

2014-04-01

To report a rare case of severe fungal keratitis caused by Scedosporium apiospermum, which was treated with a penetrating tectonic keratoplasty and aggressive medical treatment. A 62-year-old woman with a history of soil contamination of the right eye while planting vegetables presented with a severe corneal abscess and ocular pain. The patient received medical treatment and underwent tectonic keratoplasty. Both corneal scrapings and the corneal button were evaluated microscopically. The samples were sent for aerobic and anaerobic bacterial and fungal cultures. Microbiological examinations showed S. apiospermum. The isolate was sensitive to amphoterycine B, caspofungin, voriconazole, and resistant to fluconazole. No clinical improvement was achieved with topical voriconazole, vancomycin, ceftazidime, and systemic voriconazole. A penetrating tectonic keratoplasty and lensectomy with continuation of anti-fungal therapy achieved satisfactory results. A fungal etiology should be suspected in a progressive and untreatable corneal abscess. Microbiological investigation is very important in early diagnosis. Despite early diagnosis and aggressive treatment, in selected cases removing the infected tissue surgically is vital in preserving the ocular globe and vision.

Modified Descemet’s Stripping Automated Endothelial Keratoplasty: The Use of Ophthalmic Viscoelastic Devices in Hypotonic Eyes That Had Undergone Glaucoma Filtering Surgeries

Directory of Open Access Journals (Sweden)

Itaru Oyakawa

2018-01-01

Full Text Available Purpose. Descemet’s stripping automated endothelial keratoplasty (DSAEK is more difficult in hypotonic eyes with filtering bleb, due to the difficulties in elevating the intraocular pressure (IOP. We report a new method that uses ophthalmic viscoelastic devices (OVDs to achieve good graft adhesion. Case Presentation. We performed modified DSAEK surgery on 2 eyes of 2 patients, who had previously undergone a trabeculectomy. Both eyes had functioning filtering blebs; the IOP was lower than 10 mmHg without medication. After the graft was inserted into the anterior chamber, the conjunctiva was penetrated, apart from the bleb, using a 30 G needle, and Healon V® was injected into the bleb until the encapsulated space was filled completely. Air was subsequently injected into the anterior chamber to promote the graft attachment to the back surface of the cornea. The IOP was elevated above 40 mmHg in both eyes 1 h after surgery and then decreased to less than 30 mmHg over the subsequent 3 h period. The implanted graft showed good adhesion and no dislocation. Conclusions. Our novel DSAEK procedure that adds one step of OVD injection into the filtering bleb may be useful for hypotonic eyes that had undergone filtering surgeries.

In situ ultrahigh-resolution optical coherence tomography characterization of eye bank corneal tissue processed for lamellar keratoplasty.

Science.gov (United States)

Brown, Jamin S; Wang, Danling; Li, Xiaoli; Baluyot, Florence; Iliakis, Bernie; Lindquist, Thomas D; Shirakawa, Rika; Shen, Tueng T; Li, Xingde

2008-08-01

To use optical coherence tomography (OCT) as a noninvasive tool to perform in situ characterization of eye bank corneal tissue processed for lamellar keratoplasty. A custom-built ultrahigh-resolution OCT (UHR-OCT) was used to characterize donor corneal tissue that had been processed for lamellar keratoplasty. Twenty-seven donor corneas were analyzed. Four donor corneas were used as controls, whereas the rest were processed into donor corneal buttons for lamellar transplantation by using hand dissection, a microkeratome, or a femtosecond laser. UHR-OCT was also used to noninvasively characterize and monitor the viable corneal tissue immersed in storage medium over 3 weeks. The UHR-OCT captured high-resolution images of the donor corneal tissue in situ. This noninvasive technique showed the changes in donor corneal tissue morphology with time while in storage medium. The characteristics of the lamellar corneal tissue with each processing modality were clearly visible by UHR-OCT. The in situ characterization of the femtosecond laser-cut corneal tissue was noted to have more interface debris than shown by routine histology. The effects of the femtosecond laser microcavitation bubbles on the corneal tissue were well visualized at the edges of the lamellar flap while in storage medium. The results of our feasibility study show that UHR-OCT can provide superb, in situ microstructural characterization of eye bank corneal tissue noninvasively. The UHR-OCT interface findings and corneal endothelial disc thickness uniformity analysis are valuable information that may be used to optimize the modalities and parameters for lamellar tissue processing. The UHR-OCT is a powerful approach that will allow us to further evaluate the tissue response to different processing techniques for posterior lamellar keratoplasty. It may also provide information that can be used to correlate with postoperative clinical outcomes. UHR-OCT has the potential to become a routine part of tissue

Efeito imunossupressor da ciclosporina intra-muscular administrada em diferentes períodos pós-operatórios em um modelo de transplante penetrante de córnea em ratos Immunosuppressive effect of intramuscular cyclosporine used at different post-operative period on a penetrating keratoplasty model in the rat

Directory of Open Access Journals (Sweden)

Roberto von Hertwig

1999-12-01

Full Text Available Objetivo: Avaliar o efeito imunossupressor da ciclosporina intramuscular (I.M., administrada por tempo limitado em diferentes períodos do pós-operatório, no transplante penetrante de córnea em um modelo experimental em rato, por meio de avaliação clínica e anátomo-patológica do enxerto corneano. Método: Foram utilizados ratos isogênicos Fischer como doadores e Lewis como receptores, em um modelo ortotópico de transplante de córnea. A administração de ciclosporina I.M. 10 mg/kg/dia foi iniciada em diferentes períodos nos grupos estudados: no pós-operatório imediato, no 7º dia pós-operatório e no 9º dia pós-operatório. A ciclosporina quando iniciada foi administrada até o 30º dia pós-operatório. Um grupo controle não recebeu a ciclosporina I.M. Os enxertos corneanos foram avaliadas clínica e histologicamente. Resultados: Rejeição foi observada nas primeiras três semanas do pós-operatório em 100% dos casos no grupo controle (n = 5 que não recebeu a ciclosporina. Os ratos tratados com ciclosporina (n = 15 apresentaram rejeição em apenas um caso, que teve curta evolução e poucos sinais clínicos. Os estudos histológicos confirmaram as avaliações clínicas. O grupo controle apresentou infiltrado no enxerto corneal com predomínio de linfócitos sobre neutrófilos com mais neovasos, com mais fibrose e com infiltrado inflamatório mais intenso do que os grupos tratados com ciclosporina. Conclusão: Os dados obtidos indicam que a ciclosporina I.M., pode ter efeito benéfico sobre o controle da rejeição do transplante de córnea, mesmo na sua fase ativa.Purpose: Corneal graft rejection suppression after intramus-cular cyclosporine administration at different periods of time was studied on a penetrating keratoplasty rejection model in the rat. Methods: Inbred Lewis rats were used as recipients and Fischer rats were used as donors in a orthotopic rejection model of corneal transplantation. Intramuscular injection

Intraocular pressure measurements and corneal biomechanical properties using a dynamic Scheimpflug analyzer, after several keratoplasty techniques, versus normal eyes.

Science.gov (United States)

Hugo, J; Granget, E; Ho Wang Yin, G; Sampo, M; Hoffart, L

2018-01-01

To evaluate the biomechanical properties of the cornea and their impact on intraocular pressure (IOP) measurement after lamellar keratoplasty, compared to healthy eyes, using a non-contact tonometer with a Scheimpflug camera. This study, from 2014 to 2015, included 22 primary DSAEK, 5 DALK, 6 DSAEK after PK, and 50 control eyes. Using a non-contact tonometer with a high-speed Scheimpflug camera (CORVIS ST, Oculus Optikgeräte GmbH, Wetzlar, Germany), several biomechanical parameters were recorded, including radius at highest concavity (R hc ) and defomation amplitude (DA). Central corneal thickness (CCT) and uncorrected IOP, were also recorded. For the control eyes only, a corrected IOP was calculated, based on age, central corneal thickness, and biomechanical parameters. R hc was significantly lower after DALK (R hc =5.54±0.71, P=0.007) and DSAEK (R hc =6.26±0.77, P=0.042) compared to control eyes (R hc =6.82±0.76). DA was higher after DALK and DSAEK, but not significantly (respectively 1.24±0.09 P=0.41 and 1.22±0.15, P=0.923) compared to normal eyes (1.18±0.15). Uncorrected IOP was not significantly different between post-keratoplasty and control eyes. In control eyes, the corrected IOP (15.23±1.88) was lower than the uncorrected IOP (16.10±2.34); a statistically significant positive correlation between R hc and CCT (R 2 =0.6020, P<0001), and a significant negative correlation between DA and CCT (R 2 =-0.641, P<0.0001) were found. Our study showed that, after lamellar keratoplasty, corneal biomechanics are altered. Corneas with higher ocular rigidity will show a lower DA and a higher R hc . Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Highly penetrative liposome nanomedicine generated by a biomimetic strategy for enhanced cancer chemotherapy.

Science.gov (United States)

Jia, Yali; Sheng, Zonghai; Hu, Dehong; Yan, Fei; Zhu, Mingting; Gao, Guanhui; Wang, Pan; Liu, Xin; Wang, Xiaobing; Zheng, Hairong

2018-04-25

Liposome nanomedicine has been successfully applied for cancer chemotherapy in patients. However, in general, the therapeutic efficacy is confined by its limited accumulation and penetration in solid tumors. Here, we established a biomimetic strategy for the preparation of highly penetrative liposome nanomedicine for enhanced chemotherapeutic efficacy. By applying this unique type of nanomedicine, membrane proteins on the cancer cells are used as highly penetrative targeting ligands. Biomimetic liposomes are highly stable, exhibiting a superior in vitro homologous targeting ability, and a 2.25-fold deeper penetration in 3D tumor spheroids when compared to conventional liposome nanomedicine. The fluorescence/photoacoustic dual-modal imaging approach demonstrated enhanced tumor accumulation and improved tumor penetration of the biomimetic liposome in C6 glioma tumor-bearing nude mice. Following the intravenous administration of biomimetic liposome nanomedicine, the tumor inhibition rate reached up to 93.3%, which was significantly higher when compared to that of conventional liposome nanomedicine (69.3%). Moreover, histopathological analyses demonstrated that biomimetic liposome nanomedicine has limited side effects. Therefore, these results suggested that a cancer cell membrane-based biomimetic strategy may provide a breakthrough approach for enhancing drug penetration and improving treatment efficacy, holding a great promise for further clinical studies.

Accuracy of conventional imaging of penetrating torso injuries in the trauma resuscitation room

NARCIS (Netherlands)

D.S.E. Varin (Dorien); A.N. Ringburg (Akkie); E.M.M. van Lieshout (Esther); P. Patka (Peter); I.B. Schipper (Inger)

2009-01-01

textabstractChest X-ray (CXR), abdominal ultrasound, cardiac ultrasound, and abdominal X-ray are the most frequently used imaging modalities to radiologically evaluate patients with penetrating torso trauma. The aim of this study was to evaluate the accuracy of these imaging modalities. From January

Corneal perforation after conductive keratoplasty with previous refractive surgery.

Science.gov (United States)

Kymionis, George D; Titze, Patrik; Markomanolakis, Marinos M; Aslanides, Ioannis M; Pallikaris, Ioannis G

2003-12-01

A 56-year-old woman had conductive keratoplasty (CK) for residual hyperopia and astigmatism. Three years before the procedure, the patient had arcuate keratotomy, followed by laser in situ keratomileusis 2 years later for high astigmatism correction in both eyes. During CK, a corneal perforation occurred in the right eye; during the postoperative examination, an iris perforation and anterior subcapsule opacification were seen beneath the perforation site. The perforation was managed with a bandage contact lens and an antibiotic-steroid ointment; it had a negative Seidel sign by the third day. The surgery in the left eye was uneventful. Three months after the procedure, the uncorrected visual acuity was 20/32 and the best corrected visual acuity 20/20 in both eyes with a significant improvement in corneal topography. Care must be taken to prevent CK-treated spots from coinciding with areas in the corneal stroma that might have been altered by previous refractive procedures.

Penetration enhancer-containing vesicles (PEVs) as carriers for cutaneous delivery of minoxidil.

Science.gov (United States)

Mura, Simona; Manconi, Maria; Sinico, Chiara; Valenti, Donatella; Fadda, Anna Maria

2009-10-01

The aim of this work was to evaluate the ability of a few different penetration enhancers to produce elastic vesicles with soy lecithin and the influence of the obtained vesicles on in vitro (trans)dermal delivery of minoxidil. To this purpose, so-called Penetration Enhancer-containing Vesicles (PEVs) were prepared as dehydrated-rehydrated vesicles by using soy lecithin and different amounts of three penetration enhancers, 2-(2-ethoxyethoxy)ethanol (Transcutol), capryl-caproyl macrogol 8-glyceride (Labrasol), and cineole. Soy lecithin liposomes, without penetration enhancers, were used as control. Prepared formulations were characterized in terms of size distribution, morphology, zeta potential, and vesicle deformability. The influence of PEVs on (trans)dermal delivery of minoxidil was studied by in vitro diffusion experiments through newborn pig skin in comparison with traditional liposomes and ethanolic solutions of the drug also containing each penetration enhancer. A skin pre-treatment study using empty PEVs and conventional liposomes was also carried out. Results showed that all the used penetration enhancers were able to give more deformable vesicles than conventional liposomes with a good drug entrapment efficiency and stability. In vitro skin penetration data showed that PEVs were able to give a statistically significant improvement of minoxidil deposition in the skin in comparison with classic liposomes and penetration enhancer-containing drug ethanolic solutions without any transdermal delivery. Moreover, the most deformable PEVs, prepared with Labrasol and cineole, were also able to deliver to the skin a higher total amount of minoxidil than the PE alcoholic solutions thus suggesting that minoxidil delivery to the skin was strictly correlated to vesicle deformability, and therefore to vesicle composition.

Spring-action Apparatus for Fixation of Eyeball (SAFE): a novel, cost-effective yet simple device for ophthalmic wet-lab training.

Science.gov (United States)

Ramakrishnan, Seema; Baskaran, Prabu; Fazal, Romana; Sulaiman, Syed Mohammad; Krishnan, Tiruvengada; Venkatesh, Rengaraj

2016-10-01

Achieving a formed and firm eyeball which is stably fixed in a holding device is a major challenge of surgical wet-lab training. Our innovation, the 'Spring-action Apparatus for Fixation of Eyeball (SAFE)' is a robust, simple and economical device to solve this problem. It consists of a hollow iron cylinder to which a spring-action syringe is attached. The spring-action syringe generates vacuum and enables reliable fixation of a human or animal cadaveric eye on the iron cylinder. The rise in intraocular pressure due to vacuum fixation can be varied as per need or nature of surgery being practised. A mask-fixed version of this device is also designed to train surgeons for appropriate hand positioning. An experienced surgeon performed various surgeries including manual small incision cataract surgery (MSICS), phacoemulsification, laser in situ keratomileusis (LASIK), femtosecond LASIK docking, Descemet's stripping endothelial keratoplasty, deep anterior lamellar keratoplasty, penetrating keratoplasty and trabeculectomy on this device, while a trainee surgeon practised MSICS and wound suturing. Skill-appropriate comfort level was much higher with SAFE than with conventional globe holders for both surgeons. Due to its stability, pressure adjustability, portability, cost-efficiency and simplicity, we recommend SAFE as the basic equipment for every wet lab. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

[Posterior lamellar keratoplasty with DSEK technique and use of the Tan EndoGlide - short-term results].

Science.gov (United States)

Kałuiny, Bartłomiej J; Piotrowiak, Ilona; Sołdańska, Beata; Grzybek, Katarzyna; Czajkowska, Monika; Galas, Małgorzata; Malukiewicz, Grazyna

2013-01-01

To present the differences in surgical technique of DSEK (Descemet's Stripping Endothelial Keratoplasty) with the use of Tan EndoGlide (Coronet, UK) and Busin Glide (Moria, FR). Short-term results will also be presented, DSEK was performed in 24 eyes, in 8 cases the surgery was combined with cataract phacoemulsification and lOL implantation. Surgery course and 6 months postoperative results of first 12 eyes performed with the use of Tan EndoGlide were compared with 12 consecutive eyes preformed with Busin Glide. Tan EndoGlide provided much more stable anterior chamber, donor tissue unfolding process was better controlled but the incision was wider incision. Surgically induced mean refractory cylinder 6. months after the surgery was 1.56 - 1.15 Dsph in Tan EndoGlide group and 1.18 +/- 1.10 Dsph in Busin Glide group (P 0.05). Mean CDVA was 0.65+/- 0.27 and 0.63 +/- 0.25, respectively (P>0,05). Statistically significant differences in intra- and post-operative complications between both groups were not found. The Tan EndoGlide used during posterior lamellar keratoplasty with DSEK technique is a good alternative to currently used methods. It provides better stabilization of the anterior chamber, however its use is linked with higher postoperative astigmatism in comparison with Busin Glide. The visual outcomes and endothelial cell loss 6 months after the surgery were similar in both groups.

Simultaneous topography-guided PRK followed by corneal collagen cross-linking after lamellar keratoplasty for keratoconus.

Science.gov (United States)

Spadea, Leopoldo; Paroli, Marino

2012-01-01

The purpose of this paper is to report the results of using combined treatment of customized excimer laser-assisted photorefractive keratectomy (PRK) and prophylactic corneal collagen crosslinking (CXL) for residual refractive error in a group of patients who had previously undergone lamellar keratoplasty for keratoconus. The study included 14 eyes from 14 patients who had originally been treated for keratoconus in one eye by excimer laser-assisted lamellar keratoplasty (ELLK), and subsequently presented with residual ametropia (-6.11 D ± 2.48, range -2.50 to -9.50). After a mean 40.1 ± 12.4 months since ELLK they underwent combined simultaneous corneal regularization treatment with topographically guided transepithelial excimer laser PRK (central corneal regularization) and corneal CXL induced by riboflavin-ultraviolet A. After a mean 15 ± 6.5 (range 6-24) months, all eyes gained at least one Snellen line of uncorrected distance visual acuity (range 1-10). No patient lost lines of corrected distance visual acuity, and four patients gained three lines of corrected distance visual acuity. Mean manifest refractive spherical equivalent was -0.79 ± 2.09 (range +1 to -3.0) D, and topographic keratometric astigmatism was 5.02 ± 2.93 (range 0.8-8.9) D. All the corneas remained clear (haze PRK and corneal CXL provided safe and effective results in the management of corneal regularization for refractive purposes after ELLK for keratoconus.

Outcomes of LASIK and PRK in previous penetrating corneal transplant recipients.

Science.gov (United States)

Kovoor, Timmy A; Mohamed, Engy; Cavanagh, H Dwight; Bowman, R Wayne

2009-09-01

To evaluate the safety and efficacy of excimer laser refractive surgery in correcting refractive error in eyes that have undergone previous penetrating keratoplasty (PK). Twenty-three keratorefractive procedures on 16 eyes from 16 consecutive subjects were evaluated between 2002 and 2008. Each patient presented a previous history of a PK with subsequent postoperative myopia and astigmatism. Keratometric value, manifest refraction, best-corrected visual acuity, uncorrected visual acuity, and complications were determined. There were a total of 14 photorefractive keratectomy (PRK) procedures performed on 11 eyes and 9 laser in situ keratomileusis (LASIK) procedures performed on 5 eyes. In the PRK group, the preoperative post-PK manifest refractive spherical equivalent and cylindrical error were -6.22 +/- 6.23 diopter and 5.23 +/- 2.26 D, respectively. The PRK postoperative manifest refractive spherical equivalent and cylindrical error were -3.61 +/- 4.23 D (P=0.25) and 3.21 +/- 1.78 D (P=0.02), respectively. In the LASIK group, the preoperative post-PK manifest refractive spherical equivalent and cylindrical error were -3.05 +/- 3.29 D and 4.11 +/- 2.38 D, respectively. The LASIK postoperative manifest refractive spherical equivalent and cylindrical error were -1.51 +/- 2.02 D (P=0.24) and 2.08 +/- 1.26 D (P=0.03), respectively. There was a 2-line or greater improvement of uncorrected visual acuity in 8 of the 14 PRK treatments and 5 of the 9 LASIK treatments. There were two episodes of acute graft rejection. One of the episodes resolved with topical and oral corticosteroids, and the other episode required a repeat corneal transplantation. PRK and LASIK are effective tools in reducing surgically induced astigmatism after penetrating corneal transplantation in most patients in this case series. The reduction of astigmatism may allow improved contact lens or spectacle fitting to achieve best-corrected binocular visual acuity.

Study on Penetration Characteristics of Tungsten Cylindrical Penetrator

Energy Technology Data Exchange (ETDEWEB)

Jo, Jong Hyun; Lee, Young Shin; Kim, Jae Hoon [Chungnam Nat' l Univ., Daejeon (Korea, Republic of); Bae, Yong Woon [Agency for Defense Development, Daejeon (Korea, Republic of)

2013-09-15

The design of missile require extremely small warheads that must be highly efficient and lethal. The penetration characteristics of each penetrator and the total number of penetrators on the warhead are obvious key factors that influence warhead lethality. The design of the penetrator shape and size are directly related to the space and weight of the warhead. The design of the penetrator L/D was directly related to the space and weight of the warhead. L and D are the length and the diameter of the projectile, respectively. The AUTODYN-3a code was used to study the effect of penetrator penetration. The objective of numerical analysis was to determine the penetration characteristics of penetrator produced by hypervelocity impacts under different initial conditions such as initial velocity, obliquity angle and L/D of penetrator. The residual velocity and residual mass were decreased with increasing initial impact velocity under L/D{<=}4.

High-velocity Penetration of Concrete Targets with Three Types of Projectiles: Experiments and Analysis

Directory of Open Access Journals (Sweden)

Shuang Zhang

Full Text Available Abstract This study conducted high-velocity penetration experiments using conventional ogive-nose, double-ogive-nose, and grooved-tapered projectiles of approximately 2.5 kg and initial velocities between 1000 and 1360 m/s to penetrate or perforate concrete targets with unconfined compressive strengths of nominally 40MPa. The penetration performance data of these three types of projectiles with two different types of materials (i.e., AerMet100 and DT300 were obtained. The crater depth model considering both the projectile mass and the initial velocity was proposed based on the test results and a theoretical analysis. The penetration ability and the trajectory stability of these three projectile types were compared and analyzed accordingly. The results showed that, under these experimental conditions, the effects of these two different kinds of projectile materials on the penetration depth and mass erosion rate of projectile were not obvious. The existing models could not reflect the crater depths for projectiles of greater weights or higher velocities, whereas the new model established in this study was reliable. The double-ogive-nose has a certain effect of drag reduction. Thus, the double-ogive-nose projectile has a higher penetration ability than the conventional ogive-nose projectile. Meanwhile, the grooved-tapered projectile has a better trajectory stability, because the convex parts of tapered shank generated the restoring moment to stabilize the trajectory.

Influence of topical human epidermal growth factor on postkeratoplasty re-epithelialisation

NARCIS (Netherlands)

M.M. Dellaert; T.A. Casey; S. Wiffen; J. Gordon (Jocelynne); P. Johnson (Jürgen); A.J. Geerards (Annette); W.J. Rijneveld (Wilhelmina); L. Remeijer (Lies); W.H. Beekhuis (Houdijn); P.G.H. Mulder (Paul)

1997-01-01

textabstractAIM: To test the efficacy and safety of recombinant human epidermal growth factor (hEGF) on corneal re-epithelialisation following penetrating keratoplasty. METHODS: A prospective, randomised, placebo controlled study was carried out in which patients were

A case of congenital corneal keloid.

Science.gov (United States)

Song, Jong-Suk; Kwon, Sangwon; Shyn, Kyung-Hwan

2005-06-01

To describe a case of unilateral comeal keloid and present the clinical and histopathological findings and the management. A 23-year-old Asian male patient was examined for a white spot on the left cornea that had been present since birth. On biomicroscopic examination, a well-demarcated vascularized comeal mass was found located nasal to the center. The pupil was displaced superiorly, and gonioscopic examination showed peripheral iridocomeal adhesion at 12 o'clock. The patient underwent penetrating keratoplasty. Histopathologic study showed a variously thickened epithelial layer, an absence of Bowman's layer, subepithelial fibrovascular hyperplasia, and an absence of dermal elements. These histopathologic findings suggested a congenital comeal keloid. The central graft comea remained clear at 18 months after surgery and the patient was satisfied with the result. Penetrating keratoplasty may be an effective surgical option for congenital keloids in young adult patients.

Study on the Impact Characteristics of Coherent Supersonic Jet and Conventional Supersonic Jet in EAF Steelmaking Process

Science.gov (United States)

Wei, Guangsheng; Zhu, Rong; Cheng, Ting; Dong, Kai; Yang, Lingzhi; Wu, Xuetao

2018-02-01

Supersonic oxygen-supplying technologies, including the coherent supersonic jet and the conventional supersonic jet, are now widely applied in electric arc furnace steelmaking processes to increase the bath stirring, reaction rates, and energy efficiency. However, there has been limited research on the impact characteristics of the two supersonic jets. In the present study, by integrating theoretical modeling and numerical simulations, a hybrid model was developed and modified to calculate the penetration depth and impact zone volume of the coherent and conventional supersonic jets. The computational fluid dynamics results were validated against water model experiments. The results show that the lance height has significant influence on the jet penetration depth and jet impact zone volume. The penetration depth decreases with increasing lance height, whereas the jet impact zone volume initially increases and then decreases with increasing lance height. In addition, the penetration depth and impact zone volume of the coherent supersonic jet are larger than those of the conventional supersonic jet at the same lance height, which illustrates the advantages of the coherent supersonic jet in delivering great amounts of oxygen to liquid melt with a better stirring effect compared to the conventional supersonic jet. A newly defined parameter, the k value, reflects the velocity attenuation and the potential core length of the main supersonic jet. Finally, a hybrid model and its modifications can well predict the penetration depth and impact zone volume of the coherent and conventional supersonic jets.

Atypical Presentation of Iridocorneal Endothelial Syndrome With Band Keratopathy but No Corneal Edema Managed With Descemet Membrane Endothelial Keratoplasty.

Science.gov (United States)

Zygoura, Vasiliki; Lavy, Itay; Verdijk, Robert M; Santander-García, Diana; Baydoun, Lamis; Dapena, Isabel; Melles, Gerrit R J

2018-04-17

To report an unusual presentation of iridocorneal endothelial (ICE) syndrome associated with band keratopathy and its management with ethylenediamine-tetraacetic acid (EDTA) chelation and Descemet membrane endothelial keratoplasty (DMEK). A 57-year-old female patient presented with unilateral progressive painless visual impairment, corneal band keratopathy, and morphological corneal endothelial changes without corneal edema or any previous ophthalmic, medical, or family history. Routine specular and confocal microscopy imaging, as well as biomicroscopy, best-corrected visual acuity, and pachymetry measurements were performed before and after the surgical procedures. Histopathologic and immunohistochemical evaluations of the surgically excised diseased DM-endothelium were performed. Superficial epithelial keratectomy with EDTA chelation was performed. After an initial period of a few months of corneal clearance, the patient presented with recurrence of visually significant band keratopathy. After 1 year, she underwent retreatment with superficial epithelial keratectomy and EDTA chelation, followed by DMEK. Histopathologic and immunohistochemical analysis showed ICE syndrome. Two years after DMEK surgery, the cornea was still clear and band keratopathy had not recurred. To the best of our knowledge, this is the first case in the literature that reports the association of ICE syndrome with band keratopathy. As band keratopathy recurred shortly after EDTA chelation, endothelial keratoplasty (DMEK) may be indicated to successfully treat such cases.

Fluorescent in situ hybridization (FISH) on corneal impression cytology specimens (CICS): study of epithelial cell survival after keratoplasty.

Science.gov (United States)

Catanese, Muriel; Popovici, Cornel; Proust, Hélène; Hoffart, Louis; Matonti, Frédéric; Cochereau, Isabelle; Conrath, John; Gabison, Eric E

2011-02-22

To assess corneal epithelial cell survival after keratoplasty. Corneal impression cytology (CIC) was performed on sex-mismatched corneal transplants. Fluorescent in situ hybridization (FISH) with sex chromosome-specific probes was performed to identify epithelial cell mosaicism and therefore allocate the donor or recipient origin of the cells. Twenty-four samples of corneal epithelial cells derived from 21 transplanted patients were analyzed. All patients received post-operative treatment using dexamethasone eye drops, with progressive tapering over 18 months, and nine patients also received 2% cyclosporine eye drops. Out of the 24 samples reaching quality criteria, sex mosaicism was found in 13, demonstrating the presence of donor-derived cells at the center of the graft for at least 211 days post keratoplasty. Kaplan-Meier analysis established a median survival of donor corneal epithelial cells of 385 days. Although not statistically significant, the disappearance of donor cells seemed to be delayed and the average number of persistent cells appeared to be greater when 2% cyclosporine was used topically as an additional immunosuppressive therapy. The combination of corneal impressions and FISH analysis is a valuable tool with negligible side effects to investigate the presence of epithelial cell mosaicism in sex-mismatched donor transplants. Epithelial cells survived at the center of the graft with a median survival of more than one year, suggesting slower epithelial turnover than previously described.

A simple rescue maneuver for unfolding and centering a tightly rolled graft in Descemet membrane endothelial keratoplasty

Directory of Open Access Journals (Sweden)

Droutsas K

2014-10-01

Full Text Available Konstantinos Droutsas,1,2 Thomas Bertelmann,1 Frank M Schroeder,1 Dimitrios Papaconstantinou,2 Walter Sekundo1 1Department of Ophthalmology, Philipps University, Marburg, Germany; 2First Department of Ophthalmology, University of Athens, Medical School of Athens, Athens, Greece Abstract: A 74-year-old man underwent Descemet membrane endothelial keratoplasty (DMEK for endothelial decompensation due to Fuchs endothelial dystrophy. After descemetorhexis, the DMEK graft was inserted into the anterior chamber. However, unfolding of the graft was not possible as the graft was very tightly rolled together and the anterior chamber deep. After placing a 30G-cannula connected to an air-filled syringe inside the roll's lumen, a small air bubble was injected, which allowed the roll to open up, until it assumed a “taco” configuration around the bubble. Then, the graft was centered by pressing the posterior part of the roll against, and sweeping it over the iris. In the present case a “tight” DMEK roll was successfully unfolded by injection of a single air bubble into the roll’s lumen and centered by a “sweeping” the partialy unfolded graft over the iris. This technique allowed a controlled unfolding and centering of the DMEK graft with limited trauma to the donor endothelium and may be applied in cases where other less traumatic maneuvers are not successful. Keywords: Fuchs endothelial dystrophy, surgical technique, endothelial keratoplasty

Use of the Femtosecond Lasers in Ophthalmology

Directory of Open Access Journals (Sweden)

Roszkowska Anna M

2018-01-01

Full Text Available Femtosecond laser (FSL is an infrared laser with a wavelength of 1053 nm. FS laser works producing photodisruption or photoionization of the optically transparent tissue such as cornea. Currently FS lasers have a wide range of applications in ophthalmic surgery. They are used above all in corneal surgery in refractive procedures and keratoplasty, and recently in cataract surgery. The use of the FSL in corneal refractive surgery includes LASIK flap creation, astigmatic keratotomy, Femtosecond Lenticule Extraction (FLEx, Small Incision Lenticule Extraction (SMILE and channels creation for implantation of the intrastromal corneal rings. As to the corneal grafting, the FS lasers are used in laser-assisted anterior and posterior lamellar keratoplasty and customized trephination in the penetrating keratoplasty. FS Laser Assisted Cataract Surgery (FLACS includes capsulorrhexis and nuclear fragmentation that enhance safety and efficacy of the procedure.

Use of the Femtosecond Lasers in Ophthalmology

Science.gov (United States)

Roszkowska, Anna M.; Urso, Mario; Signorino, Alberto; Aragona, Pasquale

2018-01-01

Femtosecond laser (FSL) is an infrared laser with a wavelength of 1053 nm. FS laser works producing photodisruption or photoionization of the optically transparent tissue such as cornea. Currently FS lasers have a wide range of applications in ophthalmic surgery. They are used above all in corneal surgery in refractive procedures and keratoplasty, and recently in cataract surgery. The use of the FSL in corneal refractive surgery includes LASIK flap creation, astigmatic keratotomy, Femtosecond Lenticule Extraction (FLEx), Small Incision Lenticule Extraction (SMILE) and channels creation for implantation of the intrastromal corneal rings. As to the corneal grafting, the FS lasers are used in laser-assisted anterior and posterior lamellar keratoplasty and customized trephination in the penetrating keratoplasty. FS Laser Assisted Cataract Surgery (FLACS) includes capsulorrhexis and nuclear fragmentation that enhance safety and efficacy of the procedure.

New continuous air pumping technique to improve clinical outcomes of descemet-stripping automated endothelial keratoplasty in asian patients with previous ahmed glaucoma valve implantation.

Directory of Open Access Journals (Sweden)

Chang-Min Liang

Full Text Available BACKGROUND: To evaluate the outcomes of Descemet-stripping automated endothelial keratoplasty (DSAEK with the use of continuous air pumping technique in Asian eyes with previous Ahmed glaucoma valve implantation. METHODS: The DSAEK procedure was modified in that complete air retention of the anterior chamber was maintained for 10 min using continuous air pumping at 30 mm Hg. The primary outcome measurement was graft survival, and postoperative clinical features including, rate of graft detachment, endothelial cell count, intraocular pressure (IOP, surgical time and cup/disc ratio were also recorded. RESULTS: A total of 13 eyes of 13 patients which underwent modified DSAEK and 6 eyes of 6 patients which underwent conventional DSAEK were included. There was a significant difference in graft survival curves between two groups (P = 0.029; the 1-year graft survival rates were estimated as 100% and 66.7% for patients with modified DSAEK and those with traditional DSAEK, respectively. The rate of graft detachment were 0% and 33.3% for the modified DSAEK and conventional DSAEK groups, respectively (P = 0.088. The significantly lowered surgical time for air tamponade was noted in the modified DSAEK group compared to that in the conventional DSAEK group [median (IQR: 10.0 (10.0, 10.0 min vs. 24.5 (22.0, 27.0 min; P<0.001] Postoperatively, patients in the modified DSAEK group had significantly lower IOP as compared to the conventional DSAEK group [12.0 (11.0, 15.0 mm Hg vs. 16.0 (15.0, 18.0 mm Hg; P = 0.047]. Modified DSAEK patients had higher endothelial cell counts as compared to conventional DSAEK patients [2148.0 (1964.0, 2218.0 vs. 1529.0 (713.0, 2014.0], but the difference did not reach statistical significance (P = 0.072. CONCLUSIONS: New continuous air pumping technique in DSAEK can be performed safely and effectively in patients with prior GDDs placement who have corneal failure.

Photorefractive keratectomy with corneal collagen cross-linking 1 year after intrastromal corneal ring segment implantation for the treatment of keratoconus

Directory of Open Access Journals (Sweden)

Maha Elfayoumi

2016-01-01

Conclusion PRK with CXL can be used to enhance aided and unaided visual acuity after treatment of keratoconus with Intacs implants, with a stable refractive outcome, and could postpone penetrating or lamellar keratoplasty in patients with the visually disabling disease of moderate keratoconus.

HMO market penetration and hospital cost inflation in California.

Science.gov (United States)

Robinson, J C

1991-11-20

OBJECTIVE--Health maintenance organizations (HMOs) have stimulated price competition in California hospital markets since 1983, when the state legislature eliminated barriers to selective contracting by conventional health insurance plans. This study measures the impact of HMO-induced price competition on the rate of inflation in average cost per admission for 298 private, non-HMO hospitals between 1982 and 1988. DATA--HMO market penetration was calculated using discharge abstract data on insurance coverage, ZIP code of residence, and hospital of choice for 3.35 million patients in 1983 and 3.41 million patients in 1988. Data on hospital characteristics were obtained from the American Hospital Association and other sources. -HMO coverage grew from an average of 8.3% of all admissions in local hospital markets in 1983 to 17.0% of all admissions in 1988. The average rate of growth in costs per admission between 1982 and 1988 was 9.4% lower in markets with relatively high HMO penetration compared with markets with relatively low HMO penetration (95% confidence interval, 5.2 to 13.8). Cost savings for these 298 hospitals are estimated at $1.04 billion for 1988. CONCLUSION--Price competition between HMOs and conventional health insurers can significantly reduce hospital cost inflation if legislative barriers to selective contracting are removed. The impact of competition in California was modest, however, when evaluated in terms of the 74.5% average rate of California hospital cost inflation during these years.

Manual and automatic flight control during severe turbulence penetration

Science.gov (United States)

Johnston, D. E.; Klein, R. H.; Hoh, R. H.

1976-01-01

An analytical and experimental investigation of possible contributing factors in jet aircraft turbulence upsets was conducted. Major contributing factors identified included autopilot and display deficiencies, the large aircraft inertia and associated long response time, and excessive pilot workload. An integrated flight and thrust energy management director system was synthesized. The system was incorporated in a moving-base simulation and evaluated using highly experienced airline pilots. The evaluation included comparison of pilot workload and flight performance during severe turbulence penetration utilizing four control/display concepts: manual control with conventional full panel display, conventional autopilot (A/P-A) with conventional full panel display, improved autopilot (A/P-B) with conventional full panel display plus thrust director display, and longitudinal flight director with conventional full panel display plus thrust director display. Simulation results show improved performance, reduced pilot workload, and a pilot preference for the autopilot system controlling to the flight director command and manual control of thrust following the trim thrust director.

Use of glycerol-preserved corneas for corneal transplants

Directory of Open Access Journals (Sweden)

Neeti Gupta

2017-01-01

Full Text Available Purpose: This study was carried out to see the results of glycerol-preserved cornea (GPC in emergency situation when fresh corneal tissue was not available. The aim was to study the outcome of corneal transplantation using GPC. Methods: This was a retrospective study. The medical records of all the patients were reviewed, who underwent keratoplasty using “GPC” during the period from October 2011 to December 2015. The indication of keratoplasty, duration of preservation of the GPC, and its outcome were analyzed. Descriptive statistics were applied. Results: Out of the 222 penetrating keratoplasty (PKP performed over the study period, the GPC was used in 34 patients (males = 31, 91.2% aged 15–74 years. Therapeutic keratoplasty was performed in all cases in this cohort except one in which tectonic keratoplasty was done. The primary indication of PKP (91.2% was infectious keratitis. Of these, 20 (64.5% patients presented with perforated corneal ulcers. Post-PKP, ocular anatomy was preserved in 91.2%, and visual acuity of perception of light positive and accurate projection of rays in all the quadrants was obtained in 76.5% cases. Complications included glaucoma (n = 12, 35.1%, phthisis bulbi (n = 2, 5.9%, and graft reinfection and endophthalmitis after PKP (n = 1, 2.9%. The secondary procedure post-GPC and PKP were trabeculectomy with mitomycin C (n = 7, 58.3% in patients not controlled on topical antiglaucoma medication. Optical keratoplasty was performed in (n = 3 8.8% patients and triple procedure in (n = 2 5.8% patients with good visual acuity postprocedure. Conclusions: Acellular GPCs are useful in emergency keratoplasty to avoid loss of vision and can save the eye.

Descemet Stripping Automated Endothelial Keratoplasty for Endothelial Dysfunction in Xeroderma Pigmentosum: A Clinicopathological Correlation and Review of Literature.

Science.gov (United States)

Vira, Divya; Fernandes, Merle; Mittal, Ruchi

2016-07-01

Xeroderma pigmentosum (XP) mainly affects the ocular surface; however, endothelial damage may also occur. We would like to report changes in the endothelial-Descemet layer and review the literature on similar findings in patients with XP, including the role of Descemet stripping automated endothelial keratoplasty (DSAEK) in the management of a 21-year-old man who presented with nonresolving corneal edema in the right eye after excision biopsy for conjunctival intraepithelial neoplasia. His best-corrected visual acuity (BCVA) was 20/200 in the right eye and 20/20 in the left eye. On general examination, there was patchy hyperpigmentation of the exposed areas of skin suggestive of XP. On examination of the right eye, there was stromal edema involving the exposed half of cornea. The left eye appeared normal. Pachymetry readings were 860 and 600 μm in the right and left eye, respectively. Descemet stripping automated endothelial keratoplasty was performed for endothelial dysfunction and the stripped endothelium, and Descemet membrane (DM) was sent for histopathologic evaluation. Postoperatively, the donor lenticule was well apposed and the overlying stromal edema resolved. The patient achieved a BCVA of 20/30 in the right eye without progression of corneal scarring at 1-year follow-up. In the meanwhile, however, the left eye developed corneal edema. Histopathology revealed gross attenuation of endothelial cells with uniform thickness of the DM. Corneal endothelial dysfunction in XP is amenable to treatment with DSAEK.

Recurrent progressive anterior segment fibrosis syndrome following a descemet-stripping endothelial keratoplasty in an infant with congenital aniridia

Directory of Open Access Journals (Sweden)

Mihir Kothari

2014-01-01

Full Text Available Progressive anterior segment fibrosis syndrome (ASFS, after intraocular surgery in older children (≥9 years and adults with congenital aniridia, is described in the literature. In this report, we describe an unique case of ASFS in an infant with congenital aniridia following a combined trabeculotomy-ectomy and its recurrence after a descemet stripping endothelial keratoplasty. The ophthalmologists should be well aware of this entity and warn the parents about its possibilities. Use of immunomodulators or prolonged anti-inflammatory therapy may be considered to prevent its occurrence.

Why doesn't conventional IVF work in the horse?

NARCIS (Netherlands)

Leemans, Bart; Gadella, Bart M; Stout, Tom Arjun Edgar; De Schauwer, Catharina; Nelis, Hilde Maria; Hoogewijs, Maarten; Van Soom, Ann

2016-01-01

In contrast to man and many other mammalian species, conventional in vitro fertilization (IVF) with horse gametes is not reliably successful. The apparent inability of stallion spermatozoa to penetrate the zona pellucida in vitro is most likely due to incomplete activation of spermatozoa

Synthesis and processing of composites by reactive metal penetration

Energy Technology Data Exchange (ETDEWEB)

Loehman, R.E.; Ewsuk, K.G. [Sandia National Laboratories, Albuquerque, NM (United States); Tomsia, A.P. [Pask Research and Engineering, Berkeley, CA (United States)] [and others

1995-05-01

Ceramic-metal composites are being developed because their high stiffness-to weight ratios, good fracture toughness, and variable electrical and thermal properties give them advantages over more conventional materials. However, because ceramic-metal composite components presently are more expensive than monolithic materials, improvements in processing are required to reduce manufacturing costs. Reactive metal penetration is a promising new method for making ceramic- and metal-matrix composites that has the advantage of being inherently a net-shape process. This technique, once fully developed, will provide another capability for manufacturing the advanced ceramic composites that are needed for many light-weight structural and wear applications. The lower densities of these composites lead directly to energy savings in use. Near-net-shape fabrication of composite parts should lead to additional savings because costly and energy intensive grinding and machining operations are significantly reduced, and the waste generated from such finishing operations is minimized. The goals of this research program are: (1) to identify feasible compositional systems for making composites by reactive metal penetration; (2) to understand the mechanism(s) of composite formation by reactive metal penetration; and (3) to learn how to control and optimize reactive metal penetration for economical production of composites and composite coatings.

Microsporidial infection masquerading as graft rejection post-Descemet's stripping automated endothelial keratoplasty

Directory of Open Access Journals (Sweden)

Lumbini Devi

2017-01-01

Full Text Available A 51-year-old immunocompetent male with a history of Fuchs' endothelial dystrophy and immature cataract who underwent Descemet's stripping automated endothelial keratoplasty with intraocular lens implantation in both eyes presented with redness and defective vision of 1-day duration in his left eye. Slit lamp examination revealed coarse superficial punctate lesions with graft edema. He was diagnosed with acute graft rejection and treated with topical steroids. Two days later, symptoms worsened in his left eye with the involvement of his right eye showing a similar clinical picture. An infectious etiology was suspected and in vivo confocal microscopy ordered, which revealed hyperreflective dots, highly suggestive of microsporidial spores. The patient was prescribed topical fluconazole 0.3% in both eyes. This unique presentation of bilateral graft edema following microsporidial keratoconjunctivitis in postgraft patients requires a high index of suspicion as it can be easily be mistaken for and mismanaged as acute graft rejection.

Stabilization of Bilateral Progressive Rheumatoid Corneal Melt with Infliximab

Directory of Open Access Journals (Sweden)

Sheelah F. Antao

2012-01-01

Results. A patient with rheumatoid arthritis presented with bilateral PUK following a 2-month history of ocular discomfort and redness. His systemic prednisolone (PDN and methotrexate (MTX were increased and, despite an initial favorable response, bilateral recurrent corneal perforations ensued. Both eyes underwent cyanoacrylate glue repair, amniotic membrane transplantation (AMT, and penetrating keratoplasty (PKP. Recurrence of the disease and bilateral perforations of the second PKP in both eyes prompted administration of intravenous infliximab immediately after the fourth PKP. The disease activity rapidly settled in both eyes, and at eighteen-month followup, after 12 infliximab infusions, the PUK remains quiescent with no further graft thinning or perforation. Conclusion. Infliximab can be used to arrest the progression of severe bilateral rheumatoid PUK in cases that are refractory to conventional treatment.

Electrospun nanofibrous SF/P(LLA-CL) membrane: a potential substratum for endothelial keratoplasty.

Science.gov (United States)

Chen, Junzhao; Yan, Chenxi; Zhu, Mengyu; Yao, Qinke; Shao, Chunyi; Lu, Wenjuan; Wang, Jing; Mo, Xiumei; Gu, Ping; Fu, Yao; Fan, Xianqun

2015-01-01

Cornea transplant technology has progressed markedly in recent decades, allowing surgeons to replace diseased corneal endothelium by a thin lamellar structure. A thin, transparent, biocompatible, tissue-engineered substratum with corneal endothelial cells for endothelial keratoplasty is currently of interest. Electrospinning a nanofibrous structure can simulate the extracellular matrix and have beneficial effects for cell culture. Silk fibroin (SF) has good biocompatibility but poor mechanical properties, while poly(L-lactic acid-co-ε-caprolactone) (P(LLA-CL)) has good mechanical properties but poor biocompatibility. Blending SF with P(LLA-CL) can maintain the advantages of both these materials and overcome their disadvantages. Blended electrospun nanofibrous membranes may be suitable for regeneration of the corneal endothelium. The aim of this study was to produce a tissue-engineered construct suitable for endothelial keratoplasty. Five scaffolds containing different SF:P(LLA-CL) blended ratios (100:0, 75:25, 50:50, 25:75, 0:100) were manufactured. A human corneal endothelial (B4G12) cell line was cultured on the membranes. Light transmission, speed of cell adherence, cell viability (live-dead test), cell proliferation (Ki-67, BrdU staining), and cell monolayer formation were detected on membranes with the different blended ratios, and expression of some functional genes was also detected by real-time polymerase chain reaction. Different blended ratios of scaffolds had different light transmittance properties. The 25:75 blended ratio membrane had the best transmittance among these scaffolds. All electrospun nanofibrous membranes showed improved speed of cell adherence when compared with the control group, especially when the P(LLA-CL) ratio increased. The 25:75 blended ratio membranes also had the highest cell proliferation. B4G12 cells could form a monolayer on all scaffolds, and most functional genes were also stably expressed on all scaffolds. Only two genes

CISO's guide to penetration testing a framework to plan, manage, and maximize benefits

CERN Document Server

Tiller, James S

2011-01-01

CISO's Guide to Penetration Testing: A Framework to Plan, Manage, and Maximize Benefits details the methodologies, framework, and unwritten conventions penetration tests should cover to provide the most value to your organization and your customers. Discussing the process from both a consultative and technical perspective, it provides an overview of the common tools and exploits used by attackers along with the rationale for why they are used. From the first meeting to accepting the deliverables and knowing what to do with the results, James Tiller explains what to expect from all phases of th

Correlation Between Cone Penetration Rate And Measured Cone Penetration Parameters In Silty Soils

DEFF Research Database (Denmark)

Poulsen, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

2013-01-01

This paper shows, how a change in cone penetration rate affects the cone penetration measurements, hence the cone resistance, pore pressure, and sleeve friction in silty soil. The standard rate of penetration is 20 mm/s, and it is generally accepted that undrained penetration occurs in clay while...... drained penetration occurs in sand. When lowering the penetration rate, the soil pore water starts to dissipate and a change in the drainage condition is seen. In intermediate soils such as silty soils, the standard cone penetration rate may result in a drainage condition that could be undrained......, partially or fully drained. However, lowering the penetration rate in silty soils has a great significance because of the soil permeability, and only a small change in penetration rate will result in changed cone penetration measurements. In this paper, analyses will be done on data from 15 field cone...

[Endoscopically controlled optimization of trans-scleral suture fixation of posterior chamber lenses in the ciliary sulcus].

Science.gov (United States)

Althaus, C; Sundmacher, R

1993-08-01

Two technical difficulties have to be overcome in transscleral suture fixation of posterior chamber intraocular lenses (PCL) in the ciliary sulcus: first, exact needle penetration through the sulcus, and second, exact positioning of the PCL haptics in the sulcus. Incongruence of the two may lead to long-term complications by compression or even strangulation of ciliary processes. Intraocular endoscopy was used intraoperatively to visualize the site of needle penetration and the final location of the haptics in patients. It turned out that with our previously described standard techniques the precision was far less than anticipated. Thus, new technical ways had to be sought to improve the precision of positioning. In secondary implantation without perforating keratoplasty we achieved the best results when the needle was passed ab externo before opening the eye and before anterior vitrectomy, taking advantage of a precisely prepared sclerocorneal zone. Passing the needle ab externo in an already hypotonic eyeball gives much less precise results. In combination with perforating keratoplasty with an open-sky approach, needle penetration ab interno is reliable. Correct positioning of the PCL haptics is at least as difficult as correct needle penetration, a fact which up to now has mostly been ignored. In 33 consecutively operated eyes the technique of implantation and PCL design was varied under endoscopical control.(ABSTRACT TRUNCATED AT 250 WORDS)

Descemet's stripping-automated endothelial keratoplasty for symptomatic thioridazine deposits in the cornea

Directory of Open Access Journals (Sweden)

Masoumeh Mohebbi

2017-01-01

Full Text Available The aim of this study was to use Descemet's Stripping-automated Endothelial Keratoplasty (DSAEK as a novel treatment to remove thioridazine corneal deposits. A 53-year-old female presented with a 3-month history of visual loss and glare. She had been taking thioridazine (100 mg/day for 1 year for a psychiatric disorder. Dense yellowish-brown deposits had developed in the posterior stroma. Thioridazine was discontinued, and she was switched to fluoxetine. One year after discontinuation of thioridazine, her symptoms and signs did not resolve. Standard DSAEK was performed on her left eye. Two weeks after DSAEK, an anterior subcapsular cataract was detected in the same eye. Phacoemulsification and intraocular lens implantation were performed after 3 months. The left cornea became completely clear after DSAEK, and the patient's best-corrected visual acuity improved from 20/40 to 20/20 at 1 month after cataract surgery. All-visual symptoms such as glare and halos improved postoperatively. We suggest that DSAEK can be used as a novel treatment to reduce vision problems caused by thioridazine-induced corneal deposits.

Bile fistula after penetrating hepatic trauma with expectant management in the "era" of endoscopic treatment: clinical report

OpenAIRE

Armenta-Duran, Eduardo; Enríquez-Domínguez, Lenin; Díaz-Rosales, Juan de Dios; Duarte-Erives, Ever

2013-01-01

Objective: to report a clinical case of bile fistula after penetrating hepatic trauma given its low incidence, which was expectant managed by not having endoscopic retrograde cholangiopancreatography. Clinical case: we present a 28 years-old man, with biliary fistula resulting after a penetrating hepatic trauma. Discussion: bile leakage is a major complication after liver surgery and a rare one in complication of major hepatic trauma. Conventional treatment has consisted of surgical intervent...

Economic Operation of Power Systems with Significant Wind Power Penetration

DEFF Research Database (Denmark)

Farashbashi-Astaneh, Seyed-Mostafa

This dissertation addresses economic operation of power systems with high penetration of wind power. Several studies are presented to address the economic operation of power systems with high penetration of variable wind power. The main concern in such power systems is high variability...... and unpredictability. Unlike conventional power plants, the output power of a wind farm is not controllable. This brings additional complexity to operation and planning of wind dominant power systems. The key solution in face of wind power uncertainty is to enhance power system flexibility. The enhanced flexibility......, cooperative wind-storage operation is studied. Lithium-Ion battery units are chosen as storage units. A novel formulation is proposed to investigate optimal operation of a storage unit considering power system balancing conditions and wind power imbalances. An optimization framework is presented to increase...

Effects of graphite on rheological and conventional properties of bituminous binders

Directory of Open Access Journals (Sweden)

Yunus Erkuş

2017-07-01

Full Text Available In this study, the effects of graphite used for developing the rheological and conventional properties of bitumen were investigated using various bituminous binder tests. Penetration, softening point, rotational viscosity (RV, dynamic shear rheometer (DSR and bending beam rheometer (BBR tests were applied to bituminous binders modified with four different proportions of graphite by bitumen weight. The penetration values declined while softening point values increased with rising graphite content. While graphite induced 8 °C increases in mixing-compacting temperature by increasing the viscosity values, it also increased the rutting parameter. According to the BBR test, the deformation and stiffness values changed significantly with increasing graphite content, but the m-values did not change significantly. These results showed that graphite generally used for improving the thermal properties can improve to high temperature performance of mixtures. Keywords: Graphite, Bitumen, Conventional properties, Rheological properties

A review of penetration mechanisms and dynamic properties of tungsten and depleted uranium penetrators

International Nuclear Information System (INIS)

Andrew, S.P.; Caligiuri, R.D.; Eiselstein, L.E.

1991-01-01

Kinetic energy penetrators must posses the best possible combination of hardness, stiffness, strength, and fracture toughness characteristics to be effective against modern armor systems. Over the last decade, depleted uranium (DU) and tungsten alloys have been the materials of choice for kinetic energy penetrators. Du and tungsten perform abut the same against semi-infinite targets, and DU outperforms tungsten penetrators in oblique, spaced array targets, but because of environmental and subsequent cost concerns, effort has focused on improving the performance of tungsten penetrators over the last few years. However, despite recent improvements in material properties, the penetration performance of tungsten still lags behind that of DU. One possible reason is the difference in deformation mechanisms at the leading edge of the penetrator during the penetration process-DU alloys tend to shear band and sharpen as they penetrate the target material, whereas tungsten penetrators tend to mushroom and blunt. As a first step to determine whether shear banding is truly the reason for superior DU performance, a review of the fabrication, high strain-rate properties, and penetration phenomena of penetrators manufactured from both tungsten and DU alloys. Specifically, the effects of composition, processing, and heat treatment on material properties and penetration mechanisms of these alloys are discussed

Early surgical managment of penetrating ocular injuries involving the posterior segment.

Science.gov (United States)

Michels, R G

1976-09-01

Pars plana vitrectomy technic can be used in the early management of certain penetrating ocular injuries involving the posterior segment, including selected intraocular foreign bodies. This study reports the results of ten consecutive cases of intraocular foreign bodies in the posterior segment treated by a combination of vitrectomy (including lensectomy when necessary) and foreign-body extraction with forceps. The foreign body was successfully removed in nine of ten eyes, and nine of ten eyes were salvaged. This favorable experience using early vitreous surgery suggests that the vitrectomy technic can be used in other penetrating injuries involving the posterior segment that are not associated with intraocular foreign bodies. Possible indications for early vitrectomy are presented, including cases with a poor prognosis when managed by conventional methods.

Singularity of the London penetration depth at quantum critical points in superconductors.

Science.gov (United States)

Chowdhury, Debanjan; Swingle, Brian; Berg, Erez; Sachdev, Subir

2013-10-11

We present a general theory of the singularity in the London penetration depth at symmetry-breaking and topological quantum critical points within a superconducting phase. While the critical exponents and ratios of amplitudes on the two sides of the transition are universal, an overall sign depends upon the interplay between the critical theory and the underlying Fermi surface. We determine these features for critical points to spin density wave and nematic ordering, and for a topological transition between a superconductor with Z2 fractionalization and a conventional superconductor. We note implications for recent measurements of the London penetration depth in BaFe2(As(1-x)P(x))2 [K. Hashimoto et al., Science 336, 1554 (2012)].

Influence of jet thrust on penetrator penetration when studying the structure of space object blanket

Directory of Open Access Journals (Sweden)

N. A. Fedorova

2014-01-01

Full Text Available The article presents the calculation-and-theory-based research results to examine the possibility for using the jet thrust impulse to increase a penetration depth of high-velocity penetrator modules. Such devices can be used for studies of Earth surface layer composition, and in the nearest future for other Solar system bodies too. Research equipment (sensors and different instruments is housed inside a metal body of the penetrator with a sharpened nose that decreases drag force in soil. It was assumed, that this penetrator is additionally equipped with the pulse jet engine, which is fired at a certain stage of penetrator motion into target.The penetrator is considered as a rigid body of variable mass, which is subjected to drag force and reactive force applied at the moment the engine fires. A drag force was represented with a binomial empirical law, and penetrator nose part was considered to be conical. The jet thrust force was supposed to be constant during its application time. It was in accordance with assumption that mass flow and flow rate of solid propellant combustion products were constant. The amount of propellant in the penetrator was characterized by Tsiolkovsky number Z, which specifies the ratio between the fuel mass and the penetrator structure mass with no fuel.The system of equations to describe the penetrator dynamics was given in dimensionless form using the values aligned with penetration of an equivalent inert penetrator as the time and penetration depth scales. Penetration dynamics of penetrator represented in this form allowed to eliminate the influence of penetrator initial mass and its cross-section diameter on the solution results. The lack of such dependency is convenient for comparing the calculation results since they hold for penetrators of various initial masses and cross-sections.To calculate the penetration a lunar regolith was taken as a soil material. Calculations were carried out for initial velocities of

A review of penetration mechanisms and dynamic properties of tungsten and depleted uranium penetrators

International Nuclear Information System (INIS)

Andrew, S.P.; Caligiuri, R.D.; Eiselstein, L.E.

1991-01-01

Over the last decade, depleted uranium (DU) and tungsten alloys have been the materials of choice for kinetic energy penetrators. However, despite improvements in mechanical properties in recent years, the penetration performance of tungsten still lags behind that of DU. One possible reason is the difference in deformation mechanisms- DU alloys tend to shear band as they penetrate the target material, whereas tungsten penetrators tend to mushroom. As a first step to determining whether shear banding is truly the reason for superior DU performance, a review and summary of the available information was performed. This paper presents a state-of-the-art review of the formulation, high strain- rate properties, and penetration phenomena of penetrators manufactured from both tungsten and DU alloys. Specifically, the effects of composition, processing, and heat treatment on mechanical properties and penetration mechanisms of these alloys are discussed. Penetration data and models for penetration mechanisms (in particular shear banding) are also presented, as well as the applicability of these models and their salient features

Epithelial Downgrowth after Intraocular Surgery Treated with Intracameral 5-Fluorouracil

Directory of Open Access Journals (Sweden)

Nina Ni

2015-01-01

Full Text Available Purpose. To present the clinical and histopathologic correlation of two cases of epithelial downgrowth (EDG after prior intraocular surgery. Methods. Observational case reports. Results. We present two cases of EDG occurring after intraocular surgery. In both cases, after two anterior chamber injections of 5-fluorouracil (5FU, the area of EDG initially regressed. In Case 1, a limited area of EDG eventually recurred, and penetrating keratoplasty with cryotherapy was curative. In Case 2, subsequent corneal edema required Descemet-stripping automated endothelial keratoplasty, and the patient remained clinically free of EDG without further treatment. Conclusion. Intracameral 5FU may have a role in the treatment of EDG after intraocular surgery, though its precise utilization and impact remain to be defined.

Rheological, mechanical and membrane penetration properties of novel dual drug systems for percutaneous delivery.

Science.gov (United States)

Woolfson, A D; Malcolm, R K; Campbell, K; Jones, D S; Russell, J A

2000-07-03

In this study it has been demonstrated that mixtures of two solid drugs, ibuprofen and methyl nicotinate, with different but complementary pharmacological activities and which exist as a single liquid phase over a wide composition range at skin temperature, can be formulated as o/w emulsions without the use of an additional hydrophobic carrier. These novel dual drug systems provided significantly enhanced in vitro penetration rates through a model lipophilic barrier membrane compared to conventional individual formulations of each active. Thus, for ibuprofen, drug penetration flux enhancements of three- and 10-fold were observed when compared to an aqueous ibuprofen suspension and a commercial alcohol-based ibuprofen formulation, respectively. Methyl nicotinate penetration rates were shown to be similar for aqueous gels and emulsified systems. Mechanisms explaining these observations are proposed. Novel dual drug formulations of ibuprofen and methyl nicotinate, formulated within the liquid range at skin temperature, were investigated by oscillatory rheology and texture profile analysis, demonstrating the effects of drug and viscosity enhancer concentrations, and disperse phase type upon the rheological, mechanical and drug penetration properties of these systems.

A Comparative Dermal Microdialysis Study of Diclofenac QPS versus Conventional 1% Diclofenac Gel

OpenAIRE

Sanjay Kumar H. Maroo; Ketan R. Patel; Vipul Prajapati; Rajen Shah; Milind Bagul; Rakesh U. Ojha

2013-01-01

The study was designed to evaluate penetration of diclofenac through skin after application of diclofenac 4 % quick penetrating solution (Dynapar QPS) versus conventional diclofenac 1% gel. In this 2 way crossover study, 6 male healthy human subjects were randomized to receive either 1 mg of diclofenac of the Dynapar QPS (25µl) or 1 mg of diclofenac from gel (100 mg) on to the marked area of the forearm three times daily for 3 days. On day 4, after 10th application, the dermal microdialysis w...

Residential heating costs: A comparison of geothermal solar and conventional resources

Science.gov (United States)

Bloomster, C. H.; Garrett-Price, B. A.; Fassbender, L. L.

1980-08-01

The costs of residential heating throughout the United States using conventional, solar, and geothermal energy were determined under current and projected conditions. These costs are very sensitive to location, being dependent on the local prices of conventional energy supplies, local solar insolation, climate, and the proximity and temperature of potential geothermal resources. The sharp price increases in imported fuels during 1979 and the planned decontrol of domestic oil and natural gas prices have set the stage for geothermal and solar market penetration in the 1980's.

Investigating power control in autonomous power systems with increasing wind power penetration

Energy Technology Data Exchange (ETDEWEB)

Margaris, Ioannis D. [National Technical Univ. of Athens (Greece). Electric Energy Systems Lab.; Hansen, Anca D.; Sorensen, Poul [Risoe National Laboratory, Roskilde (Denmark). Wind Energy Dept.; Hatziargyriou, Nikos D. [National Technical Univ. of Athens (Greece). Electric Energy Systems Lab.; Public Power Corporation S.A., Athens (Greece)

2009-07-01

Increasing levels of wind penetration in autonomous power systems has set intensively high standards with respect to wind turbine technology during the last years. Special features of non-interconnected power systems make security issues rather critical, as the operation of large wind farms like conventional power plants is becoming a necessity. This paper includes the study case of Rhodos island, in Greece, where rapidly increasing wind penetration has started to impose serious security issues for the immediate future. The scenarios studied here correspond to reference year of study 2012 and include wind farms with three different wind turbine technologies - namely Doubly Fed Induction Generator (DFIG), Permanent Magnet Synchronous Generator (PMSG) and Active Stall Induction Generator (ASIG) based wind turbines. Aggregated models of the wind farms are being used and results for different load cases are being analyzed and discussed. The ability of wind farms to assist in some of the power system control services traditionally carried out by conventional synchronous generation is being investigated and discussed. The power grid of the island, including speed governors and automatic voltage regulators, is simulated in the dedicated power system simulation program Power Factory from DIgSILENT. (orig.)

Physical Penetration Testing: A Whole New Story in Penetration Testing

NARCIS (Netherlands)

Dimkov, T.; Pieters, Wolter

2011-01-01

Physical penetration testing plays an important role in assuring a company that the security policies are properly enforced and that the security awareness of the employees is on the appropriate level. In physical penetration tests the tester physically enters restricted locations and directly

First Aspect of Conventional Power System Assessment for High Wind Power Plants Penetration

Directory of Open Access Journals (Sweden)

A Merzic

2012-11-01

Full Text Available Most power systems in underdeveloped and developing countries are based on conventional power plants, mainly "slow-response" thermal power plants and a certain number of hydro power plants; characterized by inflexible generating portfolios and traditionally designed to meet own electricity needs. Taking into account operational capabilities of conventional power systems, their development planning will face problems with integration of notable amounts of installed capacities in wind power plants (WPP. This is what highlights the purpose of this work and in that sense, here, possible variations of simulated output power from WPP in the 10 minute and hourly time interval, which need to be balanced, are investigated, presented and discussed. Comparative calculations for the amount of installed power in WPP that can be integrated into a certain power system, according to available secondary balancing power amounts, in case of concentrated and dispersed future WPP are given. The stated has been done using a part of the power system of Bosnia and Herzegovina. In the considered example, by planned geographically distributed WPP construction, even up to cca. 74% more in installed power of WPP can be integrated into the power system than in case of geographically concentrated WPP construction, for the same available amount of (secondary balancing power. These calculations have shown a significant benefit of planned, geographically distributed WPP construction, as an important recommendation for the development planning of conventional power systems, with limited balancing options. Keywords: balancing reserves,  geographical dispersion, output power  variations

Moorfields technique of donor cornea mounting for femtosecond-assisted keratoplasty: use of viscoelastic in the artificial anterior chamber.

Science.gov (United States)

Iovieno, Alfonso; Chowdhury, Vivek; Stevens, Julian D; Maurino, Vincenzo

2012-07-01

Appropriate mounting and cutting of the donor sclero-corneal cap is often cumbersome during femtosecond laser-assisted keratoplasty. The authors describe a technique for donor cornea femtosecond laser cutting using ophthalmic viscoelastic devices. The donor sclero-corneal cap is mounted on the artificial anterior chamber using a dispersive ophthalmic viscoelastic device instead of saline solution. The chances of artificial anterior chamber pressure loss, inadequate applanation, and fluid leaks are consistently reduced with the use of dispersive ophthalmic viscoelastic devices. The speed of donor femtosecond laser cutting is increased. The viscosity and elasticity of dispersive ophthalmic viscoelastic devices greatly assist the procedure with regard to ease of applanation, corneal endothelium protection, and decreased distortion of the applanated cornea. Copyright 2012, SLACK Incorporated.

Integration of electric drive vehicles in the Danish electricity network with high wind power penetration

DEFF Research Database (Denmark)

Chandrashekhara, Divya K; Østergaard, Jacob; Larsen, Esben

2010-01-01

/conventional) which are likely to fuel these cars. The study was carried out considering the Danish electricity network state around 2025, when the EDV penetration levels would be significant enough to have an impact on the power system. Some of the interesting findings of this study are - EDV have the potential......This paper presents the results of a study carried out to examine the feasibility of integrating electric drive vehicles (EDV) in the Danish electricity network which is characterised by high wind power penetration. One of the main aims of this study was to examine the effect of electric drive...... vehicles on the Danish electricity network, wind power penetration and electricity market. In particular the study examined the effect of electric drive vehicles on the generation capacity constraints, load curve, cross border transmission capacity and the type of generating sources (renewable...

Rapid penetration into granular media visualizing the fundamental physics of rapid earth penetration

CERN Document Server

Iskander, Magued

2015-01-01

Rapid Penetration into Granular Media: Visualizing the Fundamental Physics of Rapid Earth Penetration introduces readers to the variety of methods and techniques used to visualize, observe, and model the rapid penetration of natural and man-made projectiles into earth materials. It provides seasoned practitioners with a standard reference that showcases the topic's most recent developments in research and application. The text compiles the findings of new research developments on the subject, outlines the fundamental physics of rapid penetration into granular media, and assembles a com

Contact lenses fitting after intracorneal ring segments implantation in keratoconus

Directory of Open Access Journals (Sweden)

Luciane Bugmann Moreira

2013-08-01

Full Text Available PURPOSE: Evaluate contact lenses fitting after intracorneal ring implantation for keratoconus, its visual acuity and comfort. METHODS: Retrospective study of patients undergoing contact lenses fitting, after intracorneal ring for keratoconus. The criterion for contact lens fitting was unsatisfactory visual acuity with spectacle correction as referred by the patients. All patients were intolerants to contact lenses prior to intracorneal implantation. Visual acuity analysis was done by conversion of Snellen to logMAR scales. The comfort was evaluated according subjective questioning of good, medium or poor comfort. RESULTS: Nineteen patients were included in the study. Two patients (10.5% did not achieved good comfort with contact lenses and underwent penetrating keratoplasties. All the others 17 patients showed good or medium comfort. Four rigid gas-permeable contact lenses were fitted, one piggyback approach, 3 toric soft contact lenses, 2 soft lenses specially design for keratoconus and 7 disposable soft lenses. The average visual acuity improved from 0.77 ± 0.37 to 0.19 ± 0.13 logMAR units after contact lenses fitting. CONCLUSION: Contact lens fitting after intracorneal ring is possible, provides good comfort, improves visual acuity, and therefore, may postpone the need for penetrating keratoplasty.

Tumor penetrating peptides

Directory of Open Access Journals (Sweden)

Tambet eTeesalu

2013-08-01

Full Text Available Tumor-homing peptides can be used to deliver drugs into tumors. Phage library screening in live mice has recently identified homing peptides that specifically recognize the endothelium of tumor vessels, extravasate, and penetrate deep into the extravascular tumor tissue. The prototypic peptide of this class, iRGD (CRGDKGPDC, contains the integrin-binding RGD motif. RGD mediates tumor homing through binding to αv integrins, which are selectively expressed on various cells in tumors, including tumor endothelial cells. The tumor-penetrating properties of iRGD are mediated by a second sequence motif, R/KXXR/K. This C-end Rule (or CendR motif is active only when the second basic residue is exposed at the C-terminus of the peptide. Proteolytic processing of iRGD in tumors activates the cryptic CendR motif, which then binds to neuropilin-1 activating an endocytic bulk transport pathway through tumor tissue. Phage screening has also yielded tumor-penetrating peptides that function like iRGD in activating the CendR pathway, but bind to a different primary receptor. Moreover, novel tumor-homing peptides can be constructed from tumor-homing motifs, CendR elements and protease cleavage sites. Pathologies other than tumors can be targeted with tissue-penetrating peptides, and the primary receptor can also be a vascular zip code of a normal tissue. The CendR technology provides a solution to a major problem in tumor therapy, poor penetration of drugs into tumors. The tumor-penetrating peptides are capable of taking a payload deep into tumor tissue in mice, and they also penetrate into human tumors ex vivo. Targeting with these peptides specifically increases the accumulation in tumors of a variety of drugs and contrast agents, such as doxorubicin, antibodies and nanoparticle-based compounds. Remarkably the drug to be targeted does not have to be coupled to the peptide; the bulk transport system activated by the peptide sweeps along any compound that is

LASIK hipermetrópico pós-DSAEK (Descement Stripping Automated Endotelial Keratoplasty

Directory of Open Access Journals (Sweden)

Antonio Carlos Manhas Meireles

Full Text Available RESUMO O DSAEK (Descemet stripping automated endotelial Keratoplasty é um dos procedimentos de escolha para tratamento das doenças que acometem o endotélio corneano. Apesar do sucesso terapêutico, o procedimento pode induzir uma hipermetropia residual. Em média a refração se estabiliza em um perído que varia de 6 a 12 meses após o transplante. O objetivo desse relato é descrever a evolução dessa opção terapêutica utilizada em um paciente de 54 anos portador de Distrofia de Fuchs. O paciente foi submetido ao transplante de córnea (DSAEK e a remoção do cristalino no mesmo tempo cirúrgico o que resultou em hipermetropia residual. Após 3 anos de acompanhamento apresentava-se com a melhor visão corrigida de 20/20 (Snellen no olho operado com uma refração de +3,25 -1,00 (5º. Optou-se por realização de LASIK (Laser assisted in situ Keratomileusis hipermetrópico, obtendo um resultado visual satisfatório.

Deep ocean model penetrator experiments

International Nuclear Information System (INIS)

Freeman, T.J.; Burdett, J.R.F.

1986-01-01

Preliminary trials of experimental model penetrators in the deep ocean have been conducted as an international collaborative exercise by participating members (national bodies and the CEC) of the Engineering Studies Task Group of the Nuclear Energy Agency's Seabed Working Group. This report describes and gives the results of these experiments, which were conducted at two deep ocean study areas in the Atlantic: Great Meteor East and the Nares Abyssal Plain. Velocity profiles of penetrators of differing dimensions and weights have been determined as they free-fell through the water column and impacted the sediment. These velocity profiles are used to determine the final embedment depth of the penetrators and the resistance to penetration offered by the sediment. The results are compared with predictions of embedment depth derived from elementary models of a penetrator impacting with a sediment. It is tentatively concluded that once the resistance to penetration offered by a sediment at a particular site has been determined, this quantity can be used to sucessfully predict the embedment that penetrators of differing sizes and weights would achieve at the same site

Corneal Transplantation

DEFF Research Database (Denmark)

Hjortdal, Jesper Østergaard

with less risk of rejection episodes. Besides covering updated chapters on penetrating keratoplasty, and anterior and posterior lamellar procedures, this textbook also gives a thorough overview of the history of corneal transplantation and a detailed presentation of the microstructural components...... and to assist fellows and corneal surgeons in their advice and selection of patients for the best surgical procedure considering benefi ts and risks....

The penetrating depth analysis of Lunar Penetrating Radar onboard Chang’e-3 rover

Science.gov (United States)

Xing, Shu-Guo; Su, Yan; Feng, Jian-Qing; Dai, Shun; Xiao, Yuan; Ding, Chun-Yu; Li, Chun-Lai

2017-04-01

Lunar Penetrating Radar (LPR) has successfully been used to acquire a large amount of scientific data during its in-situ detection. The analysis of penetrating depth can help to determine whether the target is within the effective detection range and contribute to distinguishing useful echoes from noise. First, this study introduces two traditional methods, both based on a radar transmission equation, to calculate the penetrating depth. The only difference between the two methods is that the first method adopts system calibration parameters given in the calibration report and the second one uses high-voltage-off radar data. However, some prior knowledge and assumptions are needed in the radar equation and the accuracy of assumptions will directly influence the final results. Therefore, a new method termed the Correlation Coefficient Method (CCM) is provided in this study, which is only based on radar data without any a priori assumptions. The CCM can obtain the penetrating depth according to the different correlation between reflected echoes and noise. To be exact, there is a strong correlation in the useful reflected echoes and a random correlation in the noise between adjacent data traces. In addition, this method can acquire a variable penetrating depth along the profile of the rover, but only one single depth value can be obtained from traditional methods. Through a simulation, the CCM has been verified as an effective method to obtain penetration depth. The comparisons and analysis of the calculation results of these three methods are also implemented in this study. Finally, results show that the ultimate penetrating depth of Channel 1 and the estimated penetrating depth of Channel 2 range from 136.9 m to 165.5 m ({\\varepsilon }r=6.6) and from 13.0 m to 17.5 m ({\\varepsilon }r=2.3), respectively.

Biomaterials as novel penetration enhancers for transdermal and dermal drug delivery systems.

Science.gov (United States)

Chen, Yang; Wang, Manli; Fang, Liang

2013-01-01

The highly organized structure of the stratum corneum provides an effective barrier to the drug delivery into or across the skin. To overcome this barrier function, penetration enhancers are always used in the transdermal and dermal drug delivery systems. However, the conventional chemical enhancers are often limited by their inability to delivery large and hydrophilic molecules, and few to date have been routinely incorporated into the transdermal formulations due to their incompatibility and local irritation issues. Therefore, there has been a search for the compounds that exhibit broad enhancing activity for more drugs without producing much irritation. More recently, the use of biomaterials has emerged as a novel method to increase the skin permeability. In this paper, we present an overview of the investigations on the feasibility and application of biomaterials as penetration enhancers for transdermal or dermal drug delivery systems.

In-place HEPA filter penetration test

International Nuclear Information System (INIS)

Bergman, W.; Wilson, K.; Elliott, J.; Bettencourt, B.; Slawski, J.W.

1997-01-01

We have demonstrated the feasibility of conducting penetration tests on high efficiency particulate air (HEPA) filters as installed in nuclear ventilation systems. The in-place penetration test, which is designed to yield equivalent penetration measurements as the standard DOP efficiency test, is based on measuring the aerosol penetration of the filter installation as a function of particle size using a portable laser particle counter. This in-place penetration test is compared to the current in-place leak test using light scattering photometers for single HEPA filter installations and for HEPA filter plenums using the shroud method. Test results show the in-place penetration test is more sensitive than the in-place leak test, has a similar operating procedure, but takes longer to conduct. Additional tests are required to confirm that the in-place penetration test yields identical results as the standard dioctyl phthalate (DOP) penetration test for HEPA filters with controlled leaks in the filter and gasket and duct by-pass leaks. Further development of the procedure is also required to reduce the test time before the in- place penetration test is practical

Assessing high wind energy penetration

International Nuclear Information System (INIS)

Tande, J.O.

1995-01-01

In order to convincingly promote installing wind power capacity as a substantial part of the energy supply system, a set of careful analyses must be undertaken. This paper applies a case study concentrated on assessing the cost/benefit of high wind energy penetration. The case study considers expanding the grid connected wind power capacity in Praia, the capital of Cape Verde. The currently installed 1 MW of wind power is estimated to supply close to 10% of the electric energy consumption in 1996. Increasing the wind energy penetration to a higher level is considered viable as the project settings are close to ideal, including a very capable national utility company, Electra, a conventional power supply system based on imported heavy fuel and gas oil, and favourable wind conditions with an estimated annual average of 9.3 m/s at the hub height of the wind turbines. With the applied case study assumptions, simulations with WINSYS over the lifetime of the assessed wind power investment show that investments up to 4.2 MW are economically viable. The economic optimum is found at 2.4 MW reaching an internal rate of return of almost 8% p.a. This 2.4 MW of wind power would, together with the existing wind power, supply over 30% of the electric consumption in 1996. Applying the recommended practices for estimating the cost of wind energy, the life-cycle cost of this 2.4 MW investment is estimated at a 7% discount rate and a 20 year lifetime to 0.26 DKK/kW h. (Author)

The Potential for Energy Storage to Provide Peaking Capacity in California Under Increased Penetration of Solar Photovoltaics

Energy Technology Data Exchange (ETDEWEB)

Denholm, Paul L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Margolis, Robert M [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-03-14

In this report, we examine the potential for replacing conventional peaking capacity in California with energy storage, including analysis of the changing technical potential with increased storage deployment and the effect of PV deployment. We examine nine years of historic load data, a range of storage durations (2-8 hours), and a range of PV penetration levels (0%-30%). We demonstrate how PV increases the ability of storage to reduce peak net demand. In the scenarios analyzed, the expected penetration of PV in California in 2020 could more than double the potential for 4-hour energy storage to provide capacity services.

Electric vehicles to support large wind power penetration in future danish power systems

DEFF Research Database (Denmark)

Pillai, Jayakrishnan Radhakrishna; Bak-Jensen, Birgitte; Thøgersen, Paul

2012-01-01

Electric Vehicles (EVs) could play major role in the future intelligent grids to support a large penetration of renewable energy in Denmark, especially electricity production from wind turbines. The future power systems aims to phase-out big conventional fossil-fueled generators with large number...... on low voltage residential networks. Significant amount of EVs could be integrated in local distribution grids with the support of intelligent grid and smart charging strategies....

Electrospun nanofibrous SF/P(LLA-CL membrane: a potential substratum for endothelial keratoplasty

Directory of Open Access Journals (Sweden)

Chen JZ

2015-05-01

Full Text Available Junzhao Chen,1,* Chenxi Yan,1,* Mengyu Zhu,1,* Qinke Yao,1 Chunyi Shao,1 Wenjuan Lu,1 Jing Wang,2 Xiumei Mo,2 Ping Gu,1 Yao Fu,1 Xianqun Fan1 1Department of Ophthalmology, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, 2Biomaterials and Tissue Engineering Laboratory, College of Chemistry and Chemical Engineering and Biotechnology, Donghua University, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: Cornea transplant technology has progressed markedly in recent decades, allowing surgeons to replace diseased corneal endothelium by a thin lamellar structure. A thin, transparent, biocompatible, tissue-engineered substratum with corneal endothelial cells for endothelial keratoplasty is currently of interest. Electrospinning a nanofibrous structure can simulate the extracellular matrix and have beneficial effects for cell culture. Silk fibroin (SF has good biocompatibility but poor mechanical properties, while poly(L-lactic acid-co-Ɛ-caprolactone (P(LLA-CL has good mechanical properties but poor biocompatibility. Blending SF with P(LLA-CL can maintain the advantages of both these materials and overcome their disadvantages. Blended electrospun nanofibrous membranes may be suitable for regeneration of the corneal endothelium. The aim of this study was to produce a tissue-engineered construct suitable for endothelial keratoplasty.Methods: Five scaffolds containing different SF:P(LLA-CL blended ratios (100:0, 75:25, 50:50, 25:75, 0:100 were manufactured. A human corneal endothelial (B4G12 cell line was cultured on the membranes. Light transmission, speed of cell adherence, cell viability (live-dead test, cell proliferation (Ki-67, BrdU staining, and cell monolayer formation were detected on membranes with the different blended ratios, and expression of some functional genes was also detected by real-time polymerase chain reaction.Results: Different blended ratios of scaffolds

WAMS Based Intelligent Operation and Control of Modern Power System with large Scale Renewable Energy Penetration

DEFF Research Database (Denmark)

Rather, Zakir Hussain

security limits. Under such scenario, progressive displacement of conventional generation by wind generation is expected to eventually lead a complex power system with least presence of central power plants. Consequently the support from conventional power plants is expected to reach its all-time low...... system voltage control responsibility from conventional power plants to wind turbines. With increased wind penetration and displaced conventional central power plants, dynamic voltage security has been identified as one of the challenging issue for large scale wind integration. To address the dynamic...... security issue, a WAMS based systematic voltage control scheme for large scale wind integrated power system has been proposed. Along with the optimal reactive power compensation, the proposed scheme considers voltage support from wind farms (equipped with voltage support functionality) and refurbished...

Penetration portion shielding structure

International Nuclear Information System (INIS)

Hayashi, Katsumi; Narita, Hitoshi; Handa, Hiroyuki; Takeuchi, Jun; Tozuka, Fumio.

1994-01-01

Openings of a plurality of shieldings for penetration members are aligned to each other, and penetration members are inserted from the openings. Then, the openings of the plurality of shielding members are slightly displaced with each other to make the penetration portions into a helical configuration, so that leakage of radiation is reduced. Upon removal of the members, reverse operation is conducted. When a flowable shielding material is used, the penetration portions are constituted with two plates having previously formed openings and pipes for connecting the openings with each other and a vessel covering the entire of them. After passing the penetration members such as a cable, the relative position of the two plates is changed by twisting, to form a helical configuration which reduces radiation leakage. Since they are bent into the helical configuration, shielding performance is extremely improved compared with a case that radiation leakage is caused from an opening of a straight pipe. In addition, since they can be returned to straight pipes, attachment, detachment and maintenance can be conducted easily. (N.H.)

In-place HEPA filter penetration test

Energy Technology Data Exchange (ETDEWEB)

Bergman, W.; Wilson, K.; Elliott, J. [Lawrence Livermore National Lab., CA (United States)] [and others

1997-08-01

We have demonstrated the feasibility of conducting penetration tests on high efficiency particulate air (HEPA) filters as installed in nuclear ventilation systems. The in-place penetration test, which is designed to yield equivalent penetration measurements as the standard DOP efficiency test, is based on measuring the aerosol penetration of the filter installation as a function of particle size using a portable laser particle counter. This in-place penetration test is compared to the current in-place leak test using light scattering photometers for single HEPA filter installations and for HEPA filter plenums using the shroud method. Test results show the in-place penetration test is more sensitive than the in-place leak test, has a similar operating procedure, but takes longer to conduct. Additional tests are required to confirm that the in-place penetration test yields identical results as the standard dioctyl phthalate (DOP) penetration test for HEPA filters with controlled leaks in the filter and gasket and duct by-pass leaks. Further development of the procedure is also required to reduce the test time before the in-place penetration test is practical. 14 refs., 14 figs., 3 tabs.

Dynamic security issues in autonomous power systems with increasing wind power penetration

DEFF Research Database (Denmark)

Margaris, I.D.; Hansen, Anca Daniela; Sørensen, Poul Ejnar

2011-01-01

Asynchronous Generator (DFAG) and Permanent Magnet Synchronous Generator (PMSG) – are applied and issues regarding interaction with the power system are investigated. This paper provides conclusions about the dynamic security of non-interconnected power systems with high wind power penetration based...... on a complete model representation of the individual components of the system; three different types of conventional generators are included in the model, while the protection system is also incorporated. The load shedding following faults is finally discussed....

[Professor WU Zhongchao's experience of penetration needling].

Science.gov (United States)

Zhang, Ning; Wang, Bing; Zhou, Yu

2016-08-12

Professor WU Zhongchao has unique application of penetration needling in clinical treatment. Professor WU applies penetration needling along meridians, and the methods of penetration needling include self-meridian penetration, exterior-interior meridian penetration, identical-name meridian penetration, different meridian penetration. The meridian differentiation is performed according to different TCM syndromes, locations and natures of diseases and acupoint nature, so as to make a comprehensive assessment. The qi movement during acupuncture is focused. In addition, attention is paid on anatomy and long-needle penetration; the sequence and direction of acupuncture is essential, and the reinforcing and reducing methods have great originality, presented with holding, waiting, pressing and vibrating. Based on classical acupoint, the acupoint of penetration needling is flexible, forming unique combination of acupoints.

Sustainability of Routine Notification and Request legislation on eye bank tissue supply and corneal transplantation wait times in Canada.

Science.gov (United States)

Lee, Kenneth; Boimer, Corey; Hershenfeld, Samantha; Sharpen, Linda; Slomovic, Allan R

2011-10-01

To assess whether provinces with Routine Notification and Request (RNR) legislation have sustained increases in corneal tissue supply and decreases in wait times for corneal transplantation surgery. Cross-sectional survey of Canadian corneal transplant (CT) surgeons and eye banks. Canadian CT surgeons and representatives from the 10 Canadian eye banks. Voluntary and anonymous surveys were distributed between July and October 2009. Eligible CT surgeons were defined as ophthalmologists who practice in Canada; currently perform Penetrating keratoplasty (PKP), Deep anterior lamellar keratoplasty (DALK), Deep lamellar endothelial keratoplasty (DLEK), Descemet stripping endothelial keratoplasty (DSEK), or Descemet membrane endothelial keratoplasty (DMEK); and have obtained tissues from a Canadian eye bank. From 2006 to 2009, for provinces with RNR legislation and where data are available, mean wait times from date of diagnosis to date of CT surgery have increased: in Ontario, from 31 ± 34 weeks to 36 ± 27 weeks; in British Columbia, from 39 ± 20 weeks to 42 ± 35 weeks; in Manitoba, from 32 ± 23 weeks to 49 ± 36 weeks. In addition, the amount of corneal tissue in RNR provinces suitable for transplant, with the exception of British Columbia, has declined between 2006 and 2008: in Ontario, 1186 tissues to 999 tissues (16% decline); in Manitoba, 92 tissues to 83 tissues (10% decline); in New Brunswick, 129 tissues to 98 tissues (24% decline). Although initially effective, RNR legislation has not sustained an increase in corneal tissue availability nor has it shortened wait times in most provinces. Incorporation of community hospitals into the RNR catchment, improved enforcement, and continued education of hospital staff regarding the RNR process may be effective in making this legislation more sustainable in the long term. Copyright © 2011 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Metasploit penetration testing cookbook

CERN Document Server

Agarwal, Monika

2013-01-01

This book follows a Cookbook style with recipes explaining the steps for penetration testing with WLAN, VOIP, and even cloud computing. There is plenty of code and commands used to make your learning curve easy and quick.This book targets both professional penetration testers as well as new users of Metasploit, who wish to gain expertise over the framework and learn an additional skill of penetration testing, not limited to a particular OS. The book requires basic knowledge of scanning, exploitation, and the Ruby language.

Modeling of Oblique Penetration into Geologic Targets Using Cavity Expansion Penetrator Loading with Target free-Surface Effects

Energy Technology Data Exchange (ETDEWEB)

Jung, Joe; Longcope, Donald B.; Tabbara, Mazen R.

1999-05-03

A procedure has been developed to represent the loading on a penetrator and its motion during oblique penetration into geologic media. The penetrator is modeled with the explicit dynamics, finite element computer program PRONTO 3D and the coupled pressure on the penetrator is given in a new loading option based on a separate cavity expansion (CE) solution that accounts for the pressure-reduction from a nearby target free surface. The free-surface influ- ence distance is selected in a predictive manner by considering the pressure to expand a spherical cavity in a finite radius sphere of the target material. The CE/PRONTO 3D procedure allows a detailed description of the penetrator for predicting shock environments or structural failure dur- ing the entire penetration event and is sufficiently rapid to be used in design optimization. It has been evaluated by comparing its results with data from two field tests of a full-scale penetrator into frozen soil at an impact angles of 49.6 and 52.5 degrees from the horizontal. The measured penetrator rotations were 24 and 22 degrees, respectively. In the simulation, the rotation was21 degrees and predominately resulted from the pressure reduction of the free surface. Good agree- ment was also found for the penetration depth and axial and lateral acceleration at two locations in the penetrator.

A Mass Loss Penetration Model to Investigate the Dynamic Response of a Projectile Penetrating Concrete considering Mass Abrasion

Directory of Open Access Journals (Sweden)

NianSong Zhang

2015-01-01

Full Text Available A study on the dynamic response of a projectile penetrating concrete is conducted. The evolutional process of projectile mass loss and the effect of mass loss on penetration resistance are investigated using theoretical methods. A projectile penetration model considering projectile mass loss is established in three stages, namely, cratering phase, mass loss penetration phase, and remainder rigid projectile penetration phase.

FAA Fluorescent Penetrant Activities - An Update

Energy Technology Data Exchange (ETDEWEB)

Moore, D.G.

1998-10-20

The Federal Aviation Administration's Airworthiness Assurance NDI Validation Center (AANC) is currently characterizing low cycle fatigue specimens that will support the needs of penetrant manufacturers, commercial airline industry and the Federal Aviation Administration. The main focus of this characterization is to maintain and enhance the evaluation of penetrant inspection materials and apply resources to support the aircraft community needs. This paper discusses efforts to-date to document the Wright Laboratory penetrant evaluation process and characterize penetrant brightness readings in the initial set of sample calibration panels using Type 1 penetrant.

Penetration Tester's Open Source Toolkit

CERN Document Server

Faircloth, Jeremy

2011-01-01

Great commercial penetration testing tools can be very expensive and sometimes hard to use or of questionable accuracy. This book helps solve both of these problems. The open source, no-cost penetration testing tools presented do a great job and can be modified by the user for each situation. Many tools, even ones that cost thousands of dollars, do not come with any type of instruction on how and in which situations the penetration tester can best use them. Penetration Tester's Open Source Toolkit, Third Edition, expands upon existing instructions so that a professional can get the most accura

Intrastromal Corneal Ring Segments for Astigmatism Correction after Deep Anterior Lamellar Keratoplasty

Directory of Open Access Journals (Sweden)

Júlio C. D. Arantes

2017-01-01

Full Text Available Background. To evaluate the change in corneal astigmatism after intrastromal corneal ring segment (ICRS implantation in keratoconus patients with previous deep anterior lamellar keratoplasty (DALK. Design was a longitudinal, retrospective, interventional study. The study included 25 eyes of 24 patients with keratoconus who had DALK performed at least two years prior to ICRS implantation. All patients had a clear corneal graft with up to 8.00 D of corneal astigmatism and intolerance to contact lenses. The studied parameters were age, sex, corrected distance visual acuity (CDVA, maximum keratometry (K1, minimum keratometry (K2, spherical equivalent, and astigmatism. There was a statistically significant decrease in the postintervention analysis as follows: 3.5 D reduction in K1 (p<0.001; 1.53 D in K2 (p=0.005; and 2.52 D (p<0.001 in the average K. The spherical equivalent reduced from −3.67 D (±2.74 to −0.71 D (±2.35 (p<0.001. The topographic astigmatism reduced from 3.87 D preoperatively to 1.90 D postoperatively (p<0.001. The CDVA improved from 0.33 (±0.10 to 0.20 (±0.09, p<0.001. ICRS implantation is a useful option for the correction of astigmatism after DALK as it yields significant visual, topographic, and refractive results.

Boston Type 1 Keratoprosthesis versus Repeat Donor Keratoplasty for Corneal Graft Failure: A Systematic Review and Meta-analysis.

Science.gov (United States)

Ahmad, Sumayya; Mathews, Priya M; Lindsley, Kristina; Alkharashi, Majed; Hwang, Frank S; Ng, Sueko M; Aldave, Anthony J; Akpek, Esen Karamursel

2016-01-01

To compare repeat penetrating keratoplasty (PK) with Boston type I keratoprosthesis (KPro) implantation for full-thickness donor corneal graft failure. Previous donor graft failure is a common indication for both PK and KPro implantation. Selection of the surgical procedure is entirely dependent on the surgeon because there are no studies available for guidance. Therefore, a systematic review was undertaken to examine vision, device retention, graft clarity, and postoperative glaucoma and infection outcomes after repeat PK versus KPro implantation. Articles with data regarding repeat PK published between 1990 and 2014 were identified in PubMed, EMBASE, the Latin American and Caribbean Health Sciences Literature Database, and the Cochrane Central Register of Controlled Trials and were reviewed. Results were compared with a retrospective review of consecutive, nonrandomized, longitudinal case series of KPro implantations performed at 5 tertiary care centers in the United States. Visual acuity at 2 years was the primary outcome measure. The proportion of clear grafts in the repeat PK group, device retention in the KPro group, and the development of postoperative glaucoma and infection were secondary outcome measures. The search strategy identified 17 128 articles in the PK analysis. After screening, 26 studies (21 case series and 5 cohort studies) were included in the review. Pooled analysis of the 26 unique studies demonstrated a 42% (95% confidence interval [CI], 30%-56%) likelihood of maintaining 20/200 or better at 2 years after repeat PK, compared with an 80% (95% CI, 68%-88%) probability with KPro implantation. The probability of maintaining a clear graft at 5 years was 47% (95% CI, 40%-54%) after repeat PK, whereas the probability of retention of the KPro at 5 years was 75% (95% CI, 64%-84%). The rate of progression of glaucoma at 3 years was 25% (95% CI, 10%-44%) after repeat PK and 30% in the KPro cohort. These results demonstrate favorable outcomes of KPro

Effect of compressibility on the hypervelocity penetration

Science.gov (United States)

Song, W. J.; Chen, X. W.; Chen, P.

2018-02-01

We further consider the effect of rod strength by employing the compressible penetration model to study the effect of compressibility on hypervelocity penetration. Meanwhile, we define different instances of penetration efficiency in various modified models and compare these penetration efficiencies to identify the effects of different factors in the compressible model. To systematically discuss the effect of compressibility in different metallic rod-target combinations, we construct three cases, i.e., the penetrations by the more compressible rod into the less compressible target, rod into the analogously compressible target, and the less compressible rod into the more compressible target. The effects of volumetric strain, internal energy, and strength on the penetration efficiency are analyzed simultaneously. It indicates that the compressibility of the rod and target increases the pressure at the rod/target interface. The more compressible rod/target has larger volumetric strain and higher internal energy. Both the larger volumetric strain and higher strength enhance the penetration or anti-penetration ability. On the other hand, the higher internal energy weakens the penetration or anti-penetration ability. The two trends conflict, but the volumetric strain dominates in the variation of the penetration efficiency, which would not approach the hydrodynamic limit if the rod and target are not analogously compressible. However, if the compressibility of the rod and target is analogous, it has little effect on the penetration efficiency.

Market penetration analysis of fuel cell vehicles in Japan by using the energy system model MARKAL

International Nuclear Information System (INIS)

Endo, Eiichi

2007-01-01

The objective of the present work is to validate the hydrogen energy roadmap of Japan by analyzing the market penetration of fuel cell vehicles (FCVs) and the effects of a carbon tax using an energy system model of Japan based on MARKAL. The results of the analysis show that a hydrogen FCV would not be cost competitive until 2050 without a more severe carbon tax than the government's planned 2400 JPY/t-C carbon tax. However, as the carbon tax rate increases, instead of conventional vehicles including the gasoline hybrid electric vehicle, hydrogen FCVs gain market penetration earlier and more. By assuming a more severe carbon tax rate, such as 10 000 JPY/t-C, the market share of hydrogen FCVs approaches the governmental goal. This suggests that cheaper vehicle cost and hydrogen cost than those targeted in the roadmap should be attained or subsidies to hydrogen FCV and hydrogen refueling station will be necessary for achieving the goal of earlier market penetration. (author)

Web penetration testing with Kali Linux

CERN Document Server

Muniz, Joseph

2013-01-01

Web Penetration Testing with Kali Linux contains various penetration testing methods using BackTrack that will be used by the reader. It contains clear step-by-step instructions with lot of screenshots. It is written in an easy to understand language which will further simplify the understanding for the user.""Web Penetration Testing with Kali Linux"" is ideal for anyone who is interested in learning how to become a penetration tester. It will also help the users who are new to Kali Linux and want to learn the features and differences in Kali versus Backtrack, and seasoned penetration testers

Percutaneous penetration studies for risk assessment

DEFF Research Database (Denmark)

Sartorelli, Vittorio; Andersen, Helle Raun; Angerer, Jürgen

2000-01-01

. In order to predict the systemic risk of dermally absorbed chemicals and to enable agencies to set safety standards, data is needed on the rates of percutaneous penetration of important chemicals. Standardization of in vitro tests and comparison of their results with the in vivo data could produce...... internationally accepted penetration rates and/or absorption percentages very useful for regulatory toxicology. The work of the Percutaneous Penetration Subgroup of EC Dermal Exposure Network has been focussed on the standardization and validation of in vitro experiments, necessary to obtain internationally...... accepted penetration rates for regulatory purposes. The members of the Subgroup analyzed the guidelines on percutaneous penetration in vitro studies presented by various organizations and suggested a standardization of in vitro models for percutaneous penetration taking into account their individual...

Penetration of Photovoltaics in Greece

Directory of Open Access Journals (Sweden)

Eugenia Giannini

2015-06-01

Full Text Available Recently, an interesting experiment was completed in Greece concerning photovoltaic penetration into the electricity production sector. Based on the relevant laws and in accordance to the related European directives, an explosive penetration process was completed in less than three years, resulting in a 7% share of photovoltaics in electricity production instead of the previous negligible share. The legislation was based on licensing simplification and generous feed-in-tariffs. This approach transformed photovoltaic technology from a prohibitively expensive to a competitive one. This work aims to summarize the relevant legislation and illustrate its effect on the resulting penetration. A sigmoid-shape penetration was observed which was explained by a pulse-type driving force. The return on investment indicator was proposed as an appropriate driving force, which incorporates feed-in-tariffs and turnkey-cost. Furthermore, the resulting surcharge on the electricity price due to photovoltaic penetration was also analyzed.

Modeling of Oblique Penetration into Geologic Targets Using Cavity Expansion Penetrator Loading with Target free-Surface Effects

Energy Technology Data Exchange (ETDEWEB)

Jung, Joe; Longcope, Donald B.; Tabbara, Mazen R.

1999-06-01

A procedure has been developed to represent the loading on a penetrator and its motion during oblique penetration into geologic media. The penetrator is modeled with the explicit dynamics, finite element computer program PRONTO 3D and the coupled pressure on the penetrator is given in a new loading option based on a separate cavity expansion (CE) solution that accounts for the pressure reduction from a nearby target free surface. The free-surface influence distance is selected in a predictive manner by considering the pressure to expand a spherical cavity in a finite radius sphere of the target material. The CE/PRONTO 3D procedure allows a detailed description of the penetrator for predicting shock environments or structural failure during the entire penetra- tion event and is sufficiently rapid to be used in design optimization. It has been evaluated by comparing its results with data from two field tests of a full-scale penetrator into frozen soil at an impact angles of 49.6 and 52.5 degrees from the horizontal. The measured penetrator rotations were 24 and 22 degrees, respectively. In the simulation, the rotation was 21 degrees and predom- inately resulted from the pressure reduction of the free surface. Good agreement was also found for the penetration depth and axial and lateral acceleration at two locations in the penetrator.

Descemet Membrane Endothelial Keratoplasty Learning Curve for Graft Preparation in an Eye Bank Using 645 Donor Corneas.

Science.gov (United States)

Parekh, Mohit; Ruzza, Alessandro; Romano, Vito; Favaro, Elisa; Baruzzo, Mattia; Salvalaio, Gianni; Grassetto, Andrea; Ferrari, Stefano; Ponzin, Diego

2018-03-01

To investigate the learning curve of Descemet membrane endothelial keratoplasty (DMEK) graft preparation in an eye bank. Four operators prepared 645 DMEK grafts using the stripping technique between 2014 and 2017 at the Veneto Eye Bank Foundation, Italy. Endothelial cell loss (ECL) and tissue wastage were recorded retrospectively after DMEK preparation and correlated with the number of tissues prepared each year by each operator. On average, our operators performed 1 donor preparation a week over the course of this study. Only donors older than 60 years were used in this study, and approximately 10% of donors had diabetes. The Wilcoxon test for paired data and 1-way ANOVA were used for checking statistical significance with the Tukey test as post hoc analysis. P 0.05). There is a learning curve for DMEK graft preparation. ECL and tissue wastage can be reduced with practice and skills. However, each operator may be limited to his or her own learning capability.

Barrier penetration database

International Nuclear Information System (INIS)

Fainberg, A.; Bieber, A.M. Jr.

1978-11-01

This document is intended to supply the NRC and nuclear power plant licensees with basic data on the times required to penetrate forcibly the types of barriers commonly found in nuclear plants. These times are necessary for design and evaluation of the physical protection system required under 10CFR73.55. Each barrier listed is described in detail. Minor variations in basic barrier construction that result in the same penetration time, are also described

Concentrated solar power plants impact on PV penetration level and grid flexibility under Egyptian climate

Science.gov (United States)

Moukhtar, Ibrahim; Elbaset, Adel A.; El Dein, Adel Z.; Qudaih, Yaser; Mitani, Yasunori

2018-05-01

Photovoltaic (PV) system integration in the electric grid has been increasing over the past decades. However, the impact of PV penetration on the electric grid, especially during the periods of higher and lower generation for the solar system at the middle of the day and during cloudy weather or at night respectively, limit the high penetration of solar PV system. In this research, a Concentrated Solar Power (CSP) with Thermal Energy Storage (TES) has been aggregated with PV system in order to accommodate the required electrical power during the higher and lower solar energy at all timescales. This paper analyzes the impacts of CSP on the grid-connected PV considering high penetration of PV system, particularly when no energy storages in the form of batteries are used. Two cases have been studied, the first when only PV system is integrated into the electric grid and the second when two types of solar energy (PV and CSP) are integrated. The System Advisor Model (SAM) software is used to simulate the output power of renewable energy. Simulation results show that the performance of CSP has a great impact on the penetration level of PV system and on the flexibility of the electric grid. The overall grid flexibility increases due to the ability of CSP to store and dispatch the generated power. In addition, CSP/TES itself has inherent flexibility. Therefore, CSP reduces the minimum generation constraint of the conventional generators that allows more penetration of the PV system.

Optimal LFC SMC for three – area power system with high penetration of PV

Directory of Open Access Journals (Sweden)

Maksymilian Klimontowicz

2016-03-01

Full Text Available Electrical power systems are subjected to new trends appearing in grid structuring, electrical power sources, new control strategies, etc. The introduction of inverterbased distributed energy resources to replace conventional synchronous machines depletes the mechanical inertia, and causing the system to become more sensitive to disturbances. This paper proposed a simple and reliable solution to assure sufficient frequency stability of electrical power systems when subjected to high penetration of decoupled distributed generation. To achieve this, a decentralized sliding mode control was designed to operate as a compensator for conventional load frequency controllers. Subsequently, PV farms and battery energy storage systems were interconnected. Simulated network under different configurations were conducted using MATLAB.

Reactivation of Herpes Zoster Keratitis With Corneal Perforation After Zoster Vaccination.

Science.gov (United States)

Jastrzebski, Andre; Brownstein, Seymour; Ziai, Setareh; Saleh, Solin; Lam, Kay; Jackson, W Bruce

2017-06-01

We present a case of reactivated herpes zoster keratouveitis of 6 years duration with corneal perforation requiring penetrating keratoplasty shortly after inoculation with herpes zoster vaccine (Zostavax, Merck, Quebec, Canada). Retrospective case report. A 67-year-old woman with a 5-year history of recurrent unilateral herpes zoster keratouveitis in her right eye presented with another recurrence 2 weeks after Zostavax vaccination. Three months later, she developed descemetocele and 2 months afterward, corneal perforation, which was managed by penetrating keratoplasty. Immunohistopathological examination disclosed positive staining for varicella zoster virus in most of the keratocytes adjacent to the descemetocele and perforation, most vividly in the deeper two-thirds of the stroma where the keratocytes were most dense, but not in corneal epithelium or endothelium. Electron microscopic examination showed universally severely degenerated corneal keratocytes in the corneal stroma adjacent to the perforation with variable numbers of herpes virus capsids present in half of these cells. Only a rare normal-appearing keratocyte was identified in the more peripheral corneal stroma. We present a case of reactivation of herpes keratouveitis shortly after vaccination with Zostavax in a patient with previous herpes zoster ophthalmicus. We demonstrate, for the first time, ultrastructural evidence consistent with inactive virus capsids in diffusely degenerated keratocytes in the extracted corneal tissue.

Crosslinking and corneal cryotherapy in acanthamoeba keratitis -- a histological study.

Science.gov (United States)

Hager, Tobias; Hasenfus, A; Stachon, T; Seitz, B; Szentmáry, N

2016-01-01

Acanthamoeba keratitis is rare, but difficult to treat. Penetrating keratoplasty is performed in therapy-resistant cases. Nevertheless, subsequent recurrences occur in 40 % of the cases. In addition to triple-topical therapy (polyhexamid, propamidinisoethionat, neomycin), treatment alternatives are corneal cryotherapy and/or crosslinking (CXL). The aim of our present histological study was to analyze the persistence of acanthamoebatrophozoites and cysts, the persistence of bacteria, and activation of keratocytes in corneas of acanthamoeba keratitis patients following corneal cryotherapy and/or CXL. We analyzed histologically corneal buttons (from penetrating keratoplasties) of nine patients with acanthamoeba keratitis, following corneal cryotherapy (two patients) or a combination of crosslinking and corneal cryotherapy (seven patients), using haematoxilin–eosin, periodic acid Schiff (PAS), Gram and alpha-smooth muscle actin (alpha-SMA) stainings. Acanthamoeba trophozoites persisted in three corneas after cryotherapy and CXL. Cysts persisted in one of two corneas following corneal cryotherapy and in six of seven corneas after a combination of CXL and cryotherapy. One cornea showed positive Gram staining, but there were no alpha-SMA positive keratocytes in any of the corneas. Crosslinking and corneal cryotherapy have only limited impact on killing of acanthamoeba trophozoites, cysts, or bacteria. Corneal cryotherapy and CXL did not stimulate myofibroblastic transformation of keratocytes.

Comparison of Vibringe, EndoActivator, and needle irrigation on sealer penetration in extracted human teeth.

Science.gov (United States)

Bolles, Jordan A; He, Jianing; Svoboda, Kathy K H; Schneiderman, Emet; Glickman, Gerald N

2013-05-01

Vibringe is a new device that allows continuous sonic irrigation of the canal system during endodontic treatment. The aim of this study was to compare the effect of different irrigation systems on sealer penetration into dentinal tubules of extracted single-rooted teeth. Fifty single-rooted human teeth were instrumented and randomly divided into 4 groups: group 1 (control), saline; group 2 (conventional irrigation), 17% EDTA followed by 6% NaOCl; group 3 (EndoActivator), same irrigants as group 2; group 4 (Vibringe), same irrigants as group 2. Obturation of all teeth was done with gutta-percha and SimpliSeal labeled with fluorescent dye. Transverse sections at 1 mm and 5 mm from the root apex were examined by using confocal laser scanning microscopy. Percentage and maximum depth of sealer penetration were measured by using NIS-Elements Br 3.0 imaging software. Groups 3 and 4 had a significantly greater percentage of the canal wall penetrated by sealer at the 5-mm level than group 1 (P irrigation. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Acanthamoeba Keratitis at the King Khaled Eye Specialist Hospital

International Nuclear Information System (INIS)

Al-Mezaine, H.; Al-Muteb, M.; Al-Motowa, S.; Wagoner, M. D.

2005-01-01

To quantify the number of cases and clinical courses of Acanthamoeba keratitis treated at the King Khaled Eye Specialist Hospital (KKESH) between December 1982 and May 2005, and to review their clinical course and response to medical and surgical therapy. Retrospective review of medical records of all patients with Acanthamoeba keratitis diagnosed by the KKESH Microbiology or Pathology or Pathology Laboratory since the opening of the hospital. During a period of over 22 years, only six cases of confirmed. Acanthamoeba keratitis were diagnosedand treated at KKESH. In two cases the diagnosis was made by corneal biopsy, while four cases required examination of a histopathology specimen obtained at the time of therapeutic keratoplasty to establish the diagnosis. One eye was cured by medical therapy, while five eyes required one (4eyes) or two (1 eye) therapeutic penetrating keratoplasty (PKP) to achieve a clinical cure. Three eyes achieved good visual acuity (20/40, 20/50, 20/60), one eye achieved fair visual acuity (20/160), and two eyes suffered profound visual loss (hand motions). The incidence of Acanthamoeba keratitis may be less in Saudi Arabia than reported in Western countries although the clinical is similarly complicated, with most cases requiring therapeutic keratoplasty for definitive education of the organism. (author)

Diffusion of radioactively tagged penetrants through rubbery polymers. II. Dependence on molecular length of penetrant

International Nuclear Information System (INIS)

Rhee, C.K.; Ferry, J.D.; Fetters, L.J.

1977-01-01

The diffusion of radioactively tagged n-hexadecane, n-dotriacontane, and a polybutadiene oligomer with molecular weight 1600 has been studied in 12 rubbery polymers. Diffusion coefficients were obtained from the theory for the thin smear method: for n-hexadecane and for n-dotriacontane (with one exception), in the form appropriate for a completely miscible polymer-penetrant pair, and for the oligomer in the form appropriate for slow entry of the pentrant across the penetrant-polymer interface. For the four flexible linear penetrants, n-dodecane, n-hexadecane, n-dotriacontane, and oligomer, the ratios of diffusion coefficients (or translational friction coefficients) are nearly the same in every polymer. It is concluded that these penetrants travel with similar segmentwise motions, although that is not the case with bulkier, more rigid penetrants. For the three normal paraffins, the friction coefficient is approximately proportional to molecular weight, but that for the oligomer is smaller than would be predicted on this basis

Kali Linux wireless penetration testing essentials

CERN Document Server

Alamanni, Marco

2015-01-01

This book is targeted at information security professionals, penetration testers and network/system administrators who want to get started with wireless penetration testing. No prior experience with Kali Linux and wireless penetration testing is required, but familiarity with Linux and basic networking concepts is recommended.

Prospective Life Cycle Assessment of the Increased Electricity Demand Associated with the Penetration of Electric Vehicles in Spain

Directory of Open Access Journals (Sweden)

Zaira Navas-Anguita

2018-05-01

Full Text Available The penetration of electric vehicles (EV seems to be a forthcoming reality in the transport sector worldwide, involving significant increases in electricity demand. However, many countries such as Spain have not yet set binding policy targets in this regard. When compared to a business-as-usual situation, this work evaluates the life-cycle consequences of the increased electricity demand of the Spanish road transport technology mix until 2050. This is done by combining Life Cycle Assessment and Energy Systems Modelling under three alternative scenarios based on the low, medium, or high penetration rate of EV. In all cases, EV deployment is found to involve a relatively small percentage (<4% of the final electricity demand. Wind power and waste-to-energy plants arise as the main technologies responsible for meeting the increased electricity demand associated with EV penetration. When considering a high market penetration (20 million EV by 2050, the highest annual impacts potentially caused by the additional electricity demand are 0.93 Mt CO2 eq, 0.25 kDALY, and 30.34 PJ in terms of climate change, human health, and resources, respectively. Overall, EV penetration is concluded to slightly affect the national power generation sector, whereas it could dramatically reduce the life-cycle impacts associated with conventional transport.

Contemporary management of civilian penetrating cervicothoracic arterial injuries.

Science.gov (United States)

Weinberg, Jordan A; Moore, Andrew H; Magnotti, Louis J; Teague, Rebecca J; Ward, Tyler A; Wasmund, Joshua B; Lamb, Elena M P; Schroeppel, Thomas J; Savage, Stephanie A; Minard, Gayle; Maish, George O; Croce, Martin A; Fabian, Timothy C

2016-08-01

The management of arterial injury at the thoracic outlet has long hinged on the fundamental principles of extensile exposure and vascular anastomosis. Nonetheless, treatment options for such injuries have evolved to include both endovascular stent placement and temporary vascular shunts. The purpose of this study was to evaluate our recent experience with penetrating cervicothoracic arterial injuries in light of these developments in trauma care. Patients with penetrating injuries to the innominate, carotid, subclavian, or axillary arteries managed at a single civilian trauma center between 2000 and 2013 were categorized as the modern era (ME) cohort. The management strategies and outcomes pertaining to the ME group were compared to those of previously reported experience (PE) concerning injuries to the innominate, carotid, subclavian, or axillary arteries at the same institution from 1974 to 1988. Over the two eras, there were 202 patients: 110 in the ME group and 92 in the PE group. Most of the injuries in both groups were managed with primary repair (45% vs. 46%; p = 0.89). A similar proportion of injuries in each group was managed with anticoagulation alone (14% vs. 10%; p = 0.40). In the ME group, two cases were managed with temporary shunt placement, and endovascular stent placement was performed in 12 patients. Outcomes were similar between the groups (bivariate comparison): mortality (ME, 15% vs. PE, 14%; p = 0.76), amputation following subclavian or axillary artery injury (ME, 5% vs. PE, 4%; p = 0.58), and posttreatment stroke following carotid injury (ME, 2% vs. PE, 6%; p = 0.57). Experience with penetrating arterial cervicothoracic injuries at a high-volume urban trauma center remained remarkably similar with respect to both anatomic distribution of injury and treatment. Conventional operative exposure and repair remain the cornerstone of treatment for most civilian cervicothoracic arterial injuries. Therapeutic study, level V.

Surgical therapies for corneal perforations: 10 years of cases in a tertiary referral hospital

Directory of Open Access Journals (Sweden)

Yokogawa H

2014-10-01

Full Text Available Hideaki Yokogawa, Akira Kobayashi, Natsuko Yamazaki, Toshinori Masaki, Kazuhisa Sugiyama Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, JapanPurpose: To report surgical therapies for corneal perforations in a tertiary referral hospital.Methods: Thirty-one eyes of 31 patients (aged 62.4±18.3 years with surgically treated corneal perforations from January 2002 to July 2013 were included in this study. Demographic data such as cause of corneal perforation, surgical procedures, and visual outcomes were retrospectively analyzed.Results: The causes of corneal perforation (n=31 were divided into infectious (n=8, 26% and noninfectious (n=23, 74% categories. Infectious causes included fungal ulcer, herpetic stromal necrotizing keratitis, and bacterial ulcer. The causes of noninfectious keratopathy included corneal melting after removal of a metal foreign body, severe dry eye, lagophthalmos, canaliculitis, the oral anticancer drug S-1, keratoconus, rheumatoid arthritis, neurotrophic ulcer, atopic keratoconjunctivitis, and unknown causes. Initial surgical procedures included central large corneal graft (n=17, small corneal graft (n=7, and amniotic membrane transplantation (n=7. In two cases the perforation could not be sealed during the first surgical treatment and required subsequent procedures. All infectious keratitis required central large penetrating keratoplasty to obtain anatomical cure. In contrast, several surgical options were used for the treatment of noninfectious keratitis. After surgical treatment, anatomical cure was obtained in all cases. Mean postoperative best corrected visual acuity was better at 6 months (logMAR 1.3 than preoperatively (logMAR 1.8.Conclusion: Surgical therapies for corneal perforations in our hospital included central large lamellar/penetrating keratoplasty, small peripheral patch graft, and amniotic membrane transplantation. All treatments were effective. Corneal

Market penetration rates of new energy technologies

International Nuclear Information System (INIS)

Lund, Peter

2006-01-01

The market penetration rates of 11 different new energy technologies were studied covering energy production and end-use technologies. The penetration rates were determined by fitting observed market data to an epidemical diffusion model. The analyses show that the exponential penetration rates of new energy technologies may vary from 4 up to over 40%/yr. The corresponding take-over times from a 1% to 50% share of the estimated market potential may vary from less than 10 to 70 years. The lower rate is often associated with larger energy impacts. Short take-over times less than 25 years seem to be mainly associated with end-use technologies. Public policies and subsides have an important effect on the penetration. Some technologies penetrate fast without major support explained by technology maturity and competitive prices, e.g. compact fluorescent lamps show a 24.2%/yr growth rate globally. The penetration rates determined exhibit some uncertainty as penetration has not always proceeded close to saturation. The study indicates a decreasing penetration rate with increasing time or market share. If the market history is short, a temporally decreasing functional form for the penetration rate coefficient could be used to anticipate the probable behavior

Ethical hacking and penetration testing guide

CERN Document Server

Baloch, Rafay

2014-01-01

Requiring no prior hacking experience, Ethical Hacking and Penetration Testing Guide supplies a complete introduction to the steps required to complete a penetration test, or ethical hack, from beginning to end. You will learn how to properly utilize and interpret the results of modern-day hacking tools, which are required to complete a penetration test. The book covers a wide range of tools, including Backtrack Linux, Google reconnaissance, MetaGooFil, dig, Nmap, Nessus, Metasploit, Fast Track Autopwn, Netcat, and Hacker Defender rootkit. Supplying a simple and clean explanation of how to effectively utilize these tools, it details a four-step methodology for conducting an effective penetration test or hack.Providing an accessible introduction to penetration testing and hacking, the book supplies you with a fundamental understanding of offensive security. After completing the book you will be prepared to take on in-depth and advanced topics in hacking and penetration testing. The book walks you through each ...

Healed corneal ulcer with keloid formation

OpenAIRE

Alkatan, Hind M.; Al-Arfaj, Khalid M.; Hantera, Mohammed; Al-Kharashi, Soliman

2012-01-01

We are reporting a 34-year-old Arabic white female patient who presented with a white mass covering her left cornea following multiple ocular surgeries and healed corneal ulcer. The lesion obscured further view of the iris, pupil and lens. The patient underwent penetrating keratoplasty and the histopathologic study of the left corneal button showed epithelial hyperplasia, absent Bowman’s layer and subepithelial fibrovascular proliferation. The histopathologic appearance was suggestive of a co...

Evaluation of the learning curve of non-penetrating glaucoma surgery.

Science.gov (United States)

Aslan, Fatih; Yuce, Berna; Oztas, Zafer; Ates, Halil

2017-08-11

To evaluate the learning curve of non-penetrating glaucoma surgery (NPGS). The study included 32 eyes of 27 patients' (20 male and 7 female) with medically uncontrolled glaucoma. Non-penetrating glaucoma surgeries performed by trainees under control of an experienced surgeon between 2005 and 2007 at our tertiary referral hospital were evaluated. Residents were separated into two groups. Humanistic training model applied to the one in the first group, he studied with experimental models before performing NPGS. Two residents in the second group performed NPGS after a conventional training model. Surgeries of the residents were recorded on video and intraoperative parameters were scored by the experienced surgeon at the end of the study. Postoperative intraocular pressure, absolute and total success rates were analyzed. In the first group 19 eyes of 16 patients and in the second group 13 eyes of 11 patients had been operated by residents. Intraoperative parameters and complication rates were not statistically significant between groups (p > 0.05, Chi-square). The duration of surgery was 32.7 ± 5.6 min in the first group and 45 ± 3.8 min in the second group. The difference was statistically significant (p < 0.001, Student's t test). Absolute and total success was 68.8 and 93.8% in the first group and 62.5 and 87.5% in the second group, respectively. The difference was not statistically significant. Humanistic and conventional training models under control of an experienced surgeon are safe and effective for senior residents who manage phacoemulsification surgery in routine cataract cases. Senior residents can practice these surgical techniques with reasonable complication rates.

Predictors of Corneal Perforation or Need for Therapeutic Keratoplasty in Severe Fungal Keratitis: A Secondary Analysis of the Mycotic Ulcer Treatment Trial II.

Science.gov (United States)

Prajna, N Venkatesh; Krishnan, Tiruvengada; Rajaraman, Revathi; Patel, Sushila; Shah, Ranjeet; Srinivasan, Muthiah; Das, Manoranjan; Ray, Kathryn J; Oldenburg, Catherine E; McLeod, Stephen D; Zegans, Michael E; Acharya, Nisha R; Lietman, Thomas M; Rose-Nussbaumer, Jennifer

2017-09-01

Identifying patients with infectious keratitis who are at risk of experiencing a poor outcome may be useful to allocate resources toward high-risk patients, particularly in resource-poor settings. To determine baseline patient and ulcer characteristics that predict a high risk of developing corneal perforation and/or the need to undergo therapeutic penetrating keratoplasty (TPK). This is a secondary analysis of Mycotic Ulcer Treatment Trial II, a multicenter, double-masked, placebo-controlled randomized clinical trial that enrolled 240 patients with smear-positive filamentous fungal corneal ulcers who enrolled between May 2010 and August 2015. Participants had a baseline visual acuity of 20/400 or worse and were randomized to receive oral voriconazole or a placebo (all participants received topical voriconazole, 1%). After 39 participants (16.3%) were enrolled, topical natamycin, 5%, was also added. The primary outcome of this secondary analysis was the rate of corneal perforation or the need to undergo TPK. The mean (SD) age at enrollment was 49 (13) years, 104 participants (43.3%) were women, and all were of Southeast Asian descent. The presence of hypopyon at baseline indicated 2.28 times the odds of the patient developing corneal perforation and/or needing TPK (95% CI, 1.18-4.40; P = .01). Study participants whose infiltrate involved the posterior one-third had a 71.4% risk of developing corneal perforation and/or needing TPK. For each 1-mm increase in the geometric mean of the infiltrate, there was 1.37 (95% CI, 1.12-1.67; P = .002) increased odds of developing perforation and/or needing TPK. Other clinical features such as visual acuity, baseline culture positivity, type of filamentous fungal organism and duration of symptoms, and demographic characteristics, such as sex and occupation, were not significant predictors in the multivariable regression analysis. These results suggest that risk stratification from baseline ulcer characteristics can

Projectile penetration into ballistic gelatin.

Science.gov (United States)

Swain, M V; Kieser, D C; Shah, S; Kieser, J A

2014-01-01

Ballistic gelatin is frequently used as a model for soft biological tissues that experience projectile impact. In this paper we investigate the response of a number of gelatin materials to the penetration of spherical steel projectiles (7 to 11mm diameter) with a range of lower impacting velocities (projectile velocity are found to be linear for all systems above a certain threshold velocity required for initiating penetration. The data for a specific material impacted with different diameter spheres were able to be condensed to a single curve when the penetration depth was normalised by the projectile diameter. When the results are compared with a number of predictive relationships available in the literature, it is found that over the range of projectiles and compositions used, the results fit a simple relationship that takes into account the projectile diameter, the threshold velocity for penetration into the gelatin and a value of the shear modulus of the gelatin estimated from the threshold velocity for penetration. The normalised depth is found to fit the elastic Froude number when this is modified to allow for a threshold impact velocity. The normalised penetration data are found to best fit this modified elastic Froude number with a slope of 1/2 instead of 1/3 as suggested by Akers and Belmonte (2006). Possible explanations for this difference are discussed. © 2013 Published by Elsevier Ltd.

Diamond knife-assisted deep anterior lamellar keratoplasty to manage keratoconus.

Science.gov (United States)

Vajpayee, Rasik B; Maharana, Prafulla K; Sharma, Namrata; Agarwal, Tushar; Jhanji, Vishal

2014-02-01

To evaluate the outcomes of a new surgical technique, diamond knife-assisted deep anterior lamellar keratoplasty (DALK), and compare its visual and refractive results with big-bubble DALK in cases of keratoconus. Tertiary eyecare hospital. Comparative case series. The visual and surgical outcomes of diamond knife-assisted DALK were compared with those of successful big-bubble DALK. Diamond knife-assisted DALK was performed in 19 eyes and big-bubble DALK, in 11 eyes. All surgeries were completed successfully. No intraoperative or postoperative complications occurred with diamond knife-assisted DALK. Six months after diamond knife-assisted DALK, the mean corrected distance visual acuity (CDVA) improved significantly from 1.87 logMAR ± 0.22 (SD) to 0.23 ± 0.06 logMAR, the mean keratometry improved from 65.99 ± 8.86 diopters (D) to 45.13 ± 1.16 D, and the mean keratometric cylinder improved from 7.99 ± 3.81 D to 2.87 ± 0.59 D (all P=.005). Postoperatively, the mean refractive astigmatism was 2.55 ± 0.49 D and the mean spherical equivalent was -1.97 ± 0.56 D. The mean logMAR CDVA (P = .06), postoperative keratometry (P=.64), refractive cylinder (P=.63), and endothelial cell loss (P=.11) were comparable between diamond knife-assisted DALK and big-bubble DALK. Diamond knife-assisted DALK was effective and predictable as a surgical technique for management of keratoconus cases. This technique has the potential to offer visual and refractive outcomes comparable to those of big-bubble DALK. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

[Descemet's stripping automated endothelial keratoplasty (DEAEK). Systematic review of clinical-effectiveness and safety].

Science.gov (United States)

Paz-Valiñas, L; de la Fuente-Cid, R; de Rojas-Silva, M V; López-Rodríguez, I; López-García, M

2015-04-01

To conduct a systematic review of the efficacy/effectiveness, safety and cost of Descemet's stripping automated endothelial keratoplasty (DSAEK) technique in patients with corneal endothelial failure. Comprehensive literature search conducted in the main biomedical databases from January-May 2012. Following a critical perusal of the total of 485 abstracts retrieved, 16 case series and one economic evaluation study were included. Corrected distance visual acuity and uncorrected distance visual acuity improved after treatment with DSAEK, attaining values of 0.6 to 0.8 and 0.5 respectively. The degree of post-DSAEK astigmatism was not significant with respect to baseline values. The main complications were graft dislocation-detachment (1.5-23%), primary failure (0-12%) and endothelial rejection (0.8-8.5%). In Fuchs' dystrophy and bullous keratopathy, data on the effectiveness of DSAEK indicate post-intervention improvement in uncorrected and corrected distance visual acuity. Astigmatism arising after DSAEK was not significant. The most significant post-DSAEK complications are linked to the viability of the graft, with the most frequent complications being dislocation-detachment and, to a lesser extent, endothelial rejection. The studies that assess DSAEK are case series, and for the most part retrospective. The quality of this type of studies is both low and limited. Copyright © 2012 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

The Basics of Hacking and Penetration Testing Ethical Hacking and Penetration Testing Made Easy

CERN Document Server

Engebretson, Patrick

2011-01-01

The Basics of Hacking and Penetration Testing serves as an introduction to the steps required to complete a penetration test or perform an ethical hack. You learn how to properly utilize and interpret the results of modern day hacking tools; which are required to complete a penetration test. Tool coverage will include, Backtrack Linux, Google, Whois, Nmap, Nessus, Metasploit, Netcat, Netbus, and more. A simple and clean explanation of how to utilize these tools will allow you  to gain a solid understanding of each of the four phases and prepare them to take on more in-depth texts and topi

Comparative evaluation of microleakage in conventional glass ionomer cements and triclosan incorporated glass ionomer cements

Directory of Open Access Journals (Sweden)

Rani Somani

2014-01-01

Full Text Available Aim and Objective: The aim of the following study is to comparatively evaluate the microleakage of triclosan incorporated GIC with conventional restorative GIC. Materials and Methods: Triclosan in powder form was added to conventional GIC to formulate a concentration of 2.5%. Class five cavities were prepared in non-carious extracted molars and were respectively restored with conventional restorative GIC and triclosan incorporated GIC. Samples were kept in 10% methylene blue dye. Ground sections were obtained and were observed under a binocular microscope for dye penetration. Result: No significant difference was found in the microleakage of two groups. Conclusion: Triclosan incorporated GIC can be considered as an alternative to GIC with enhanced antibacterial property.

Low Force Penetration of Icy Regolith

Science.gov (United States)

Mantovani, J. G.; Galloway, G. M.; Zacny, K.

2016-01-01

A percussive cone penetrometer measures the strength of granular material by using percussion to deliver mechanical energy into the material. A percussive cone penetrometer was used in this study to penetrate a regolith ice mixture by breaking up ice and decompacting the regolith. As compared to a static cone penetrometer, percussion allows low reaction forces to push a penetrometer probe tip more easily into dry regolith in a low gravity environment from a planetary surface rover or a landed spacecraft. A percussive cone penetrates icy regolith at ice concentrations that a static cone cannot penetrate. In this study, the percussive penetrator was able to penetrate material under 65 N of down-force which could not be penetrated using a static cone under full body weight. This paper discusses using a percussive cone penetrometer to discern changes in the concentration of water-ice in a mixture of lunar regolith simulant and ice to a depth of one meter. The rate of penetration was found to be a function of the ice content and was not significantly affected by the down-force. The test results demonstrate that this method may be ideal for a small platform in a reduced gravity environment. However, there are some cases where the system may not be able to penetrate the icy regolith, and there is some risk of the probe tip becoming stuck so that it cannot be retracted. It is also shown that a percussive cone penetrometer could be used to prospect for water ice in regolith at concentrations as high as 8 by weight.

Ground penetrating radar

CERN Document Server

Daniels, David J

2004-01-01

Ground-penetrating radar has come to public attention in recent criminal investigations, but has actually been a developing and maturing remote sensing field for some time. In the light of recent expansion of the technique to a wide range of applications, the need for an up-to-date reference has become pressing. This fully revised and expanded edition of the best-selling Surface-Penetrating Radar (IEE, 1996) presents, for the non-specialist user or engineer, all the key elements of this technique, which span several disciplines including electromagnetics, geophysics and signal processing. The

Quercetin topical application, from conventional dosage forms to nanodosage forms.

Science.gov (United States)

Hatahet, T; Morille, M; Hommoss, A; Devoisselle, J M; Müller, R H; Bégu, S

2016-11-01

Skin is a multifunctional organ with activities in protection, metabolism and regulation. Skin is in a continuous exposure to oxidizing agents and inflammogens from the sun and from the contact with the environment. These agents may overload the skin auto-defense capacity. To strengthen skin defense mechanisms against oxidation and inflammation, supplementation of exogenous antioxidants is a promising strategy. Quercetin is a flavonoid with very pronounced effective antioxidant and antiinflammatory activities, and thus a candidate of first choice for such skin supplementation. Quercetin showed interesting actions in cellular and animal based models, ranging from protecting cells from UV irradiation to support skin regeneration in wound healing. However, due to its poor solubility, quercetin has limited skin penetration ability, and various formulation approaches were taken to increase its dermal penetration. In this article, the quercetin antioxidant and antiinflammatory activities in wound healing and supporting skin against aging are discussed in detail. In addition, quercetin topical formulations from conventional emulsions to novel nanoformulations in terms of skin penetration enhancement are also presented. This article gives a comprehensive review of quercetin for topical application from biological effects to pharmaceutical formulation design for the last 25 years of research. Copyright © 2016 Elsevier B.V. All rights reserved.

Long-rod penetration: the transition zone between rigid and hydrodynamic penetration modes

Directory of Open Access Journals (Sweden)

Jian-feng Lou

2014-06-01

Full Text Available Long-rod penetration in a wide range of velocity means that the initial impact velocity varies in a range from tens of meters per second to several kilometers per second. The long rods maintain rigid state when the impact velocity is low, the nose of rod deforms and even is blunted when the velocity gets higher, and the nose erodes and fails to lead to the consumption of long projectile when the velocity is very high due to instantaneous high pressure. That is, from low velocity to high velocity, the projectile undergoes rigid rods, deforming non-erosive rods, and erosive rods. Because of the complicated changes of the projectile, no well-established theoretical model and numerical simulation have been used to study the transition zone. Based on the analysis of penetration behavior in the transition zone, a phenomenological model to describe target resistance and a formula to calculate penetration depth in transition zone are proposed, and a method to obtain the boundary velocity of transition zone is determined. A combined theoretical analysis model for three response regions is built by analyzing the characteristics in these regions. The penetration depth predicted by this combined model is in good agreement with experimental result.

Interface Fluid Syndrome After Laser In Situ Keratomileusis (LASIK) Because of Fuchs Endothelial Dystrophy Reversed by Descemet Membrane Endothelial Keratoplasty (DMEK).

Science.gov (United States)

Luceri, Salvatore; Baksoellah, Zainab; Ilyas, Abbas; Baydoun, Lamis; Melles, Gerrit R J

2016-12-01

To describe a case that developed "interface fluid syndrome" after previous laser in situ keratomileusis (LASIK) because of Fuchs endothelial dystrophy (FED), which was reversed by Descemet membrane endothelial keratoplasty (DMEK). A 58-year-old male patient presented with bilateral visual impairment owing to FED and visually significant cataract. Cataract surgery was carried out in both eyes followed by DMEK in his left eye. After cataract surgery, visual acuity did not improve sufficiently because corneal thickness increased and a fine cleft with interface fluid developed between the LASIK-flap and the residual stromal bed. After uneventful DMEK in his left eye, the fluid resolved within a week and visual acuity improved rapidly. This case demonstrates that "interface fluid syndrome" after LASIK caused by concomitant endothelial dysfunction may be reversed by DMEK allowing fast visual recovery.

Plutonium in depleted uranium penetrators

International Nuclear Information System (INIS)

McLaughlin, J.P.; Leon-Vintro, L.; Smith, K.; Mitchell, P.I.; Zunic, Z.S.

2002-01-01

Depleted Uranium (DU) penetrators used in the recent Balkan conflicts have been found to be contaminated with trace amounts of transuranic materials such as plutonium. This contamination is usually a consequence of DU fabrication being carried out in facilities also using uranium recycled from spent military and civilian nuclear reactor fuel. Specific activities of 239+240 Plutonium generally in the range 1 to 12 Bq/kg have been found to be present in DU penetrators recovered from the attack sites of the 1999 NATO bombardment of Kosovo. A DU penetrator recovered from a May 1999 attack site at Bratoselce in southern Serbia and analysed by University College Dublin was found to contain 43.7 +/- 1.9 Bq/kg of 239+240 Plutonium. This analysis is described. An account is also given of the general population radiation dose implications arising from both the DU itself and from the presence of plutonium in the penetrators. According to current dosimetric models, in all scenarios considered likely ,the dose from the plutonium is estimated to be much smaller than that due to the uranium isotopes present in the penetrators. (author)

Ethical Dilemmas and Dimensions in Penetration Testing

OpenAIRE

Faily, Shamal; McAlaney, John; Iacob, C.

2015-01-01

Penetration testers are required to attack systems to evaluate their security, but without engaging in unethical behaviour while doing so. Despite work on hacker values and studies into security practice, there is little literature devoted to the ethical pressures associated with penetration testing. This paper presents several ethical dilemmas and dimensions associated with penetration testing;\\ud these shed light on the ethical positions taken by Penetration testers, and help identify poten...

Abstracts from the 5th International Conference for Healthcare and Medical Students (ICHAMS)

OpenAIRE

Sweeney, Yvonne; O?Neill, Hugh; Duffy, Garry; Creegan, Daniel; Bustos, Viviana; Harvey, Brian J.; Dalphy, Alexander; O?Grady, Anthony; Kay, Elaine; Samelska, Katarzyna; Izdebska, Justyna; Kurowska, Anna; Al-Zubaidy, Rena; Mroz, Magdalena; Harvey, Brian

2016-01-01

Table of contents O1: Assessing the protective effect of dexrazoxane against doxorubicin-induced toxicity in HL-1 cardiomyocytes Yvonne Sweeney, Hugh O?Neill, Garry Duffy O2: Role of KCNQ1 in epithelial barrier repair Daniel Creegan, Viviana Bustos, Brian J. Harvey O3: The suitability of non-small cell lung cancer cytology preparations for the analysis of anaplastic lymphoma kinase gene rearrangements Alexander Dalphy, Anthony O?Grady, Elaine Kay O4: Penetrating keratoplasty and descemet?s st...

Ceratoplastia endotelial lamelar profunda em distrofia de Fuchs: relato de caso Deep lamellar endothelial keratoplasty in Fuchs' dystrophy: case report

Directory of Open Access Journals (Sweden)

Fernando Trench de Oliveira Komatsu

2004-08-01

Full Text Available Descrever o caso de paciente portador de distrofia de Fuchs submetido a ceratoplastia endotelial lamelar profunda. O procedimento cirúrgico foi realizado no olho direito em um caso de distrofia de Fuchs com falência endotelial. Realizou-se incisão límbica superior, o estroma corneano foi delaminado e um disco lamelar de 8,5 mm com 0,150 mm de espessura, contendo estroma, membrana de Descemet e endotélio, foi transplantado sem sutura corneana. Foram avaliados: acuidade visual sem e com correção, biomicroscopia, topografia, paquimetria ultra-sônica e densidade endotelial. A paciente apresentava na avaliação pré-operatória acuidade visual com correção de 20/100 (+4,00 DE -3,25 DC x 60º, astigmatismo de 6,6 dioptrias (37,5 a 12º x 44,1 a 102º, espessura paquimétrica de 0,625 mm e contagem endotelial de 720 cel/mm². Após três meses da cirurgia, apresentava-se com acuidade visual com correção de 20/30 (-1,25 DE -0,50 DC x 45º, astigmatismo regular de 1,0 dioptria (37,2 a 75º x 38,2 a 165º, espessura paquimétrica de 0,503 mm e contagem endotelial de 2447 cel/mm². Observaram-se como complicações: corte inadvertido da íris, má coaptação de bordas, dobras do disco doador e nébula na interface. Os resultados preliminares sugerem que a ceratoplastia endotelial lamelar posterior é uma alternativa para o tratamento cirúrgico da distrofia de Fuchs com falência endotelial. Seguimento mais prolongado e maior número de casos são necessários para melhor entendimento e caracterização desta técnica e de suas repercussões.To report a case of deep lamellar endothelial keratoplasty (DLEK technique applied to a patient with Fuchs' dystrophy. The surgical procedure was performed on the right eye for a case of Fuchs' dystrophy with endothelial failure. Through a 9 mm self-sealing scleral tunnel incision, a stromal pocket was dissected at 0.35 mm depth. A 8.5 mm lamellar donor disc with 0.150 mm thickness, containing posterior

Skull penetrating wound

International Nuclear Information System (INIS)

Gonzalez Orlandi, Yvei; Junco Martin, Reinel; Rojas Manresa, Jorge; Duboy Limonta, Victor; Matos Herrera, Omar; Saez Corvo, Yunet

2011-01-01

The cranioencephalic trauma is common in the emergence centers to care for patients with multiple traumata and it becames in a health problem in many countries. Skull penetrating trauma is located in a special place due to its low frequency. In present paper a case of male patient aged 52 severely skull-injured with penetrating wound caused by a cold steel that remained introduced into the left frontotemporal region. After an imaging study the emergence surgical treatment was applied and patient evolves adequately after 25 days of hospitalization. Nowadays, she is under rehabilitation treatment due to a residual right hemiparesis.(author)

Blunt penetration technique for treatment of a completely obstructed anastomosis after rectal resection: a case report.

Science.gov (United States)

Yazawa, Keiichi; Morioka, Daisuke; Matsumoto, Chizuru; Miura, Yasuhiko; Togo, Shinji

2014-06-27

We present a case of completely obstructed anastomosis after rectal resection which was nonsurgically and successfully treated with a blunt penetration technique using a commonly used device for transanal ileus drainage. The technique we used in this case has not been previously reported. A 79-year-old Japanese man underwent redo rectal resection for completely separated anastomosis which was caused by anastomotic leakage after a sigmoidectomy performed 3 years previously that was remedied by diverging ileostomy. Immediately after the redo surgery, fluoroscopy showed good passage through the colorectal anastomosis but no anastomotic leakage. However, fluoroscopy and colonoscopy prior to the ileostomy takedown showed complete obstruction of the anastomosis. Unlike usual anastomotic strictures, the lumen between colon oral and rectum anal to the anastomosis was completely discontinued by a membranous structure. Therefore, a conventional balloon dilatation technique was unsuitable for this condition. We applied a blunt penetration technique using a commercially available device designed as a transanal drainage system for obstructing colorectal cancer to restore the continuity between the colon oral and rectum anal to the anastomosis. After restoring the continuity, we performed conventional balloon dilatation for the anastomosis and successfully treated the anastomotic obstruction. Subsequently, the patient underwent ileostomy takedown and is currently doing well 12 months after the ileostomy takedown. The penetration technique we applied is easy and less stressful to adopt because it does not require usage of materials specialized for other particular purposes. Furthermore, we believe that this technique is superior in safety to other reported methods for this condition even if applied in the wrong direction because this technique does not utilize electrocision or sharp needle puncture.

MDCT diagnosis of penetrating diaphragm injury

Energy Technology Data Exchange (ETDEWEB)

Bodanapally, Uttam K.; Shanmuganathan, Kathirkamanathan; Mirvis, Stuart E.; Sliker, Clint W.; Fleiter, Thorsten R.; Sarada, Kamal; Miller, Lisa A. [University of Maryland School of Medicine, Department of Diagnostic Radiology, Baltimore, MD (United States); Stein, Deborah M. [University of Maryland, Department of Surgery, Shock Trauma Center, Baltimore, MD (United States); Alexander, Melvin [National Study Center for Trauma and Emergency Medical Systems, Baltimore, MD (United States)

2009-08-15

The purpose of the study was to determine the diagnostic sensitivity and specificity of multidetector CT (MDCT) in detection of diaphragmatic injury following penetrating trauma. Chest and abdominal CT examinations performed preoperatively in 136 patients after penetrating trauma to the torso with injury trajectory in close proximity to the diaphragm were reviewed by radiologists unaware of surgical findings. Signs associated with diaphragmatic injuries in penetrating trauma were noted. These signs were correlated with surgical diagnoses, and their sensitivity and specificity in assisting the diagnosis were calculated. CT confirmed diaphragmatic injury in 41 of 47 injuries (sensitivity, 87.2%), and an intact diaphragm in 71 of 98 patients (specificity, 72.4%). The overall accuracy of MDCT was 77%. The most accurate sign helping the diagnosis was contiguous injury on either side of the diaphragm in single-entry penetrating trauma (sensitivity, 88%; specificity, 82%). Thus MDCT has high sensitivity and good specificity in detecting penetrating diaphragmatic injuries. (orig.)

MDCT diagnosis of penetrating diaphragm injury

International Nuclear Information System (INIS)

Bodanapally, Uttam K.; Shanmuganathan, Kathirkamanathan; Mirvis, Stuart E.; Sliker, Clint W.; Fleiter, Thorsten R.; Sarada, Kamal; Miller, Lisa A.; Stein, Deborah M.; Alexander, Melvin

2009-01-01

The purpose of the study was to determine the diagnostic sensitivity and specificity of multidetector CT (MDCT) in detection of diaphragmatic injury following penetrating trauma. Chest and abdominal CT examinations performed preoperatively in 136 patients after penetrating trauma to the torso with injury trajectory in close proximity to the diaphragm were reviewed by radiologists unaware of surgical findings. Signs associated with diaphragmatic injuries in penetrating trauma were noted. These signs were correlated with surgical diagnoses, and their sensitivity and specificity in assisting the diagnosis were calculated. CT confirmed diaphragmatic injury in 41 of 47 injuries (sensitivity, 87.2%), and an intact diaphragm in 71 of 98 patients (specificity, 72.4%). The overall accuracy of MDCT was 77%. The most accurate sign helping the diagnosis was contiguous injury on either side of the diaphragm in single-entry penetrating trauma (sensitivity, 88%; specificity, 82%). Thus MDCT has high sensitivity and good specificity in detecting penetrating diaphragmatic injuries. (orig.)

Synthesis and processing of composites by reactive metal penetration

Energy Technology Data Exchange (ETDEWEB)

Loehman, R.E.; Ewsuk, K.G. [Sandia National Labs., Albuquerque, NM (United States); Tomsia, A.P. [Pask Research and Engineering, Berkeley, CA (United States)] [and others

1997-04-01

Achieving better performance in commercial products and processes often is dependent on availability of new and improved materials. Ceramic-metal composites have advantages over more conventional materials because of their high stiffness-to-weight ratios, good fracture toughness, and because their electrical and thermal properties can be varied through control of their compositions and microstructures. However, ceramic composites will be more widely used only when their costs are competitive with other materials and when designers have more confidence in their reliability. Over the past four years reactive metal penetration has been shown to be a promising technique for making ceramic and metal-matrix composites to near-net-shape with control of both composition and microstructure. It appears that, with sufficient development, reactive metal penetration could be an economical process for manufacturing many of the advanced ceramic composites that are needed for light-weight structural and wear applications for transportation and energy conversion devices. Near-net-shape fabrication of parts is a significant advantage because costly and energy intensive grinding and machining operations are substantially reduced, and the waste generated from such finishing operations is minimized. The most promising compositions to date consist of Al and Al{sub 2}O{sub 3}; thus, these composites should be of particular interest to the aluminum industry. The goals of this ceramic-metal composite research and development program are: (1) to identify compositions favorable for making composites by reactive metal penetration; (2) to understand the mechanism(s) by which these composites are formed; (3) to control and optimize the process so that composites and composite coatings can be made economically; and (4) to apply R&D results to problems of interest to the aluminum industry.

Risk reserve constrained economic dispatch model with wind power penetration

Energy Technology Data Exchange (ETDEWEB)

Zhou, W.; Sun, H.; Peng, Y. [Department of Electrical and Electronics Engineering, Dalian University of Technology, Dalian, 116024 (China)

2010-12-15

This paper develops a modified economic dispatch (ED) optimization model with wind power penetration. Due to the uncertain nature of wind speed, both overestimation and underestimation of the available wind power are compensated using the up and down spinning reserves. In order to determine both of these two reserve demands, the risk-based up and down spinning reserve constraints are presented considering not only the uncertainty of available wind power, but also the load forecast error and generator outage rates. The predictor-corrector primal-dual interior point method is utilized to solve the proposed ED model. Simulation results of a system with ten conventional generators and one wind farm demonstrate the effectiveness of the proposed method. (authors)

FAA Fluorescent Penetrant Laboratory Inspections

Energy Technology Data Exchange (ETDEWEB)

WINDES,CONNOR L.; MOORE,DAVID G.

2000-08-02

The Federal Aviation Administration Airworthiness Assurance NDI Validation Center currently assesses the capability of various non-destructive inspection (NDI) methods used for analyzing aircraft components. The focus of one such exercise is to evaluate the sensitivity of fluorescent liquid penetrant inspection. A baseline procedure using the water-washable fluorescent penetrant method defines a foundation for comparing the brightness of low cycle fatigue cracks in titanium test panels. The analysis of deviations in the baseline procedure will determine an acceptable range of operation for the steps in the inspection process. The data also gives insight into the depth of each crack and which step(s) of the inspection process most affect penetrant sensitivities. A set of six low cycle fatigue cracks produced in 6.35-mm thick Ti-6Al-4V specimens was used to conduct the experiments to produce sensitivity data. The results will document the consistency of the crack readings and compare previous experiments to find the best parameters for water-washable penetrant.

Muon-spin-rotation measurements of the London penetration depths in YBa2Cu3O6.97

International Nuclear Information System (INIS)

Puempin, B.; Keller, H.; Kuendig, W.; Odermatt, W.; Savic, I.M.; Schneider, J.W.; Simmler, H.; Zimmermann, P.; Kaldis, E.; Rusiecki, S.; Maeno, Y.; Rossel, C.

1990-01-01

Muon-spin-rotation (μSR) experiments on a high-quality sintered YBa 2 Cu 3 O x sample [x=6.970(1)] were performed, in order to obtain an accurate knowledge of the magnitude and the temperature dependence of the magnetic penetration depth in this copper oxide superconductor. Special attention was given to the data analysis. In particular, the systematic errors introduced by different types of analyses were estimated. Our results show that the temperature dependence of the effective penetration depth λ eff into the sintered sample is well described by the two-fluid model, with λ eff (0)=155(10) nm. This behavior of λ eff (T) is consistent with conventional s-wave pairing. With the anisotropy ratio γ=λ c /λ ab =5(1) measured in a previous μSR experiment, the penetration depths λ ab (0)=130(10) nm and λ c (0)=500--800 nm (parallel and perpendicular to the CuO 2 planes, respectively) were extracted. Our results are compared with those obtained by other experimental techniques and theoretical predictions

Operating methods to remove the excess of penetrant in surface. Preponderant and characteristic part of water for water washable penetrants

International Nuclear Information System (INIS)

Dubosc, P.

1985-01-01

Penetrant use for quality control, although very well known (nuclear, space industries, offshore platforms) is often poorly practiced. This is largely due to a lack of understanding by the users the way that the different components of the system (penetrants, solvents, emulsifiers, and developers) function. In this talk, we shall explain a particular characteristic that the manufacturers of reputable penetrant seek to build into their water washable penetrants. It is a viscosity curve which has the function of keeping water in a well defined form. We show why the form of the curve is crucial, which reaction between water and penetrant it corresponds to, and we deduce the practical consequences of bringing into play procedures for removing excess penetrant with or without water [fr

Endophthalmitis after descemet stripping endothelial keratoplasty with concave-oriented dislocation on slit-lamp optical coherence topography.

Science.gov (United States)

Kaiura, Terry L; Ritterband, David C; Koplin, Richard S; Shih, Carolyn; Palmierto, Pat M; Seedor, John A

2010-02-01

To present the first reported case of Descemet membrane stripping endothelial keratoplasty (DSEK)-associated endophthalmitis with concave dislocation on slit-lamp optical coherence topography (SL-OCT). An 86-year-old man underwent DSEK for corneal decompensation secondary to prior surgery. On all postoperative visits, a slit-lamp examination and SL-OCT were performed. On the first postoperative day, the lenticle was dislocated in a concave configuration as imaged with the SL-OCT. On the second postoperative day, the patient had eye pain, nausea, and increased intraocular pressure. On SL-OCT imaging, the concave configuration and fibrin stranding were imaged. With intraocular pressure lowering, the patient's pain subsided, and he was scheduled for a lenticle refloat the following day. The next day, endophthalmitis was diagnosed secondary to exuberant purulent inflammation. At surgery, the lenticle was removed, cultures were obtained, and pars plana vitrectomy and intravitreal injections were administered. Intraoperative cultures were positive for heavy growth of Streptococcus pneumoniae. Endophthalmitis is a potential complication for any intraocular procedure including DSEK. SL-OCT imaging postoperatively may reveal concave lenticle configuration and subtle anterior chamber fibrin stranding may be early sign of endophthalmitis.

Varieties of cognitive penetration in visual perception.

Science.gov (United States)

Vetter, Petra; Newen, Albert

2014-07-01

Is our perceptual experience a veridical representation of the world or is it a product of our beliefs and past experiences? Cognitive penetration describes the influence of higher level cognitive factors on perceptual experience and has been a debated topic in philosophy of mind and cognitive science. Here, we focus on visual perception, particularly early vision, and how it is affected by contextual expectations and memorized cognitive contents. We argue for cognitive penetration based on recent empirical evidence demonstrating contextual and top-down influences on early visual processes. On the basis of a perceptual model, we propose different types of cognitive penetration depending on the processing level on which the penetration happens and depending on where the penetrating influence comes from. Our proposal has two consequences: (1) the traditional controversy on whether cognitive penetration occurs or not is ill posed, and (2) a clear-cut perception-cognition boundary cannot be maintained. Copyright © 2014 Elsevier Inc. All rights reserved.

Theoretical analysis and design of hydro-hammer with a jet actuator: An engineering application to improve the penetration rate of directional well drilling in hard rock formations.

Science.gov (United States)

He, Jiang-Fu; Liang, Yun-Pei; Li, Li-Jia; Luo, Yong-Jiang

2018-01-01

Rapid horizontal directional well drilling in hard or fractured formations requires efficient drilling technology. The penetration rate of conventional hard rock drilling technology in horizontal directional well excavations is relatively low, resulting in multiple overgrinding of drill cuttings in bottom boreholes. Conventional drilling techniques with reamer or diamond drill bit face difficulties due to the long construction periods, low penetration rates, and high engineering costs in the directional well drilling of hard rock. To improve the impact energy and penetration rate of directional well drilling in hard formations, a new drilling system with a percussive and rotary drilling technology has been proposed, and a hydro-hammer with a jet actuator has also been theoretically designed on the basis of the impulse hydro-turbine pressure model. In addition, the performance parameters of the hydro-hammer with a jet actuator have been numerically and experimentally analyzed, and the influence of impact stroke and pumped flow rate on the motion velocity and impact energy of the hydro-hammer has been obtained. Moreover, the designed hydro-hammer with a jet actuator has been applied to hard rock drilling in a trenchless drilling program. The motion velocity of the hydro-hammer ranges from 1.2 m/s to 3.19 m/s with diverse flow rates and impact strokes, and the motion frequency ranges from 10 Hz to 22 Hz. Moreover, the maximum impact energy of the hydro-hammer is 407 J, and the pumped flow rate is 2.3 m3/min. Thus, the average penetration rate of the optimized hydro-hammer improves by over 30% compared to conventional directional drilling in hard rock formations.

Fibrin glue as agent for sealing corneal and conjunctival wound leaks.

Science.gov (United States)

Scalcione, C; Ortiz-Vaquerizas, D; Said, D G; Dua, H S

2018-02-01

PurposeTo describe a novel use of fibrin glue in managing leaking blebs and leaking wounds following trauma or surgery.MethodsInterventional case series.ResultsWe report eight patients, including three where intra-operative or immediate post-penetrating keratoplasty recalcitrant leaks from the graft-host junction and/or openings created by the needle pass, were noted. All three had thin recipient beds in the sector of leak. This was managed by intra-cameral injection of fibrin glue in the affected quadrant. This stopped the leak and allowed the defect to heal. One patient of Descemets-stripping-endothelial-keratoplasty had leak from the surgical wound, which was also sealed with fibrin glue. Two patients with leaking glaucoma-surgery-related blebs were treated with intra-bleb injection of fibrin glue to stop the leak. One patient with a penetrating corneal injury with a metal wire had a brisk leak upon removal of the wire. This was sealed with fibrin glue. Another patient of chemical burn with spontaneous leaks was managed by glue injection in the perforations. Transient rise of intraocular pressure in one patient with a leaking bleb was the only adverse event recorded.ConclusionThis novel adaptation of the application of fibrin glue can help to deal with persistent intra-operative, post-operative and traumatic aqueous and air leaks.

Precut cornea for Descemet's stripping endothelial keratoplasty: experience at a single eye bank.

Science.gov (United States)

Mohamed, Ashik; Chaurasia, Sunita; Chandragiri, Venkataswamy; Kandhibanda, Srinivas; Gunnam, Srinivas; Garg, Prashant

2017-06-01

The aim of the study is to describe the experience with precut facility for endothelial keratoplasty at a single eye bank affiliated to a tertiary eye care center in India. Data on precut tissues from Nov 2012 to Dec 2014 were retrospectively reviewed from the electronic database of the eye bank of a tertiary eye care center in South India. Donor characteristic data including donor age, precut and postcut endothelial cell density (ECD), recipient age, and thickness of graft were collected. The number of precuts increased from 42 in 2012 (Nov and Dec) and 422 in 2013 to 584 in 2014. Of the total of 1048 precuts, seven (0.67 %) were miscut and could not be utilized for transplants. The donor age ranged from 2 to 89 years. A mean change of 43.6 ± 325.2 cells/mm 2 in ECD was noted after cut, proportional increase in mean being 1.9 %. The change in ECD after cut was negatively correlated with ECD before cut. The recipient age ranged from 1 to 89 years. The median thickness of donor lenticule after cut was 148 µm (interquartile range 131-166 µm). Analysis of precut donor corneas from a single eye bank shows that the ECD of the processed tissues was excellent for transplantation. The tissue wastage in the hands of eye bank personal was minimal.

Correlation of microstructure with dynamic deformation behavior and penetration performance of tungsten heavy alloys fabricated by mechanical alloying

Science.gov (United States)

Kim, Dong-Kuk; Lee, Sunghak; Ryu, Ho Jin; Hyunghong, Soon; Noh, Joon-Woong

2000-10-01

In this study, tungsten heavy alloy specimens were fabricated by mechanical alloying (MA), and their dynamic torsional properties and penetration performance were investigated. Dynamic torsional tests were conducted on the specimens fabricated with different sintering temperatures after MA, and then the test data were compared with those of a conventionally processed specimen. Refinement of tungsten particles was obtained after MA, but contiguity was seriously increased, thereby leading to low ductility and impact energy. Specimens in which both particle size and contiguity were simultaneously reduced by MA and two-step sintering and those having higher matrix fraction by partial MA were successfully fabricated. The dynamic test results indicated that the formation of adiabatic shear bands was expected because of the plastic localization at the central area of the gage section. Upon highspeed impact testing of these specimens, self-sharpening was promoted by the adiabatic shear band formation, but their penetration performance did not improve since much of kinetic energy of the penetrators was consumed for the microcrack formation due to interfacial debonding and cleavage fracture of tungsten particles. In order to improve penetration performance as well as to achieve selfsharpening by applying MA, conditions of MA and sintering process should be established so that alloy densification, particle refinement, and contiguity reduction can be simultaneously achieved.

Numerical simulation of water and sand blowouts when penetrating through shallow water flow formations in deep water drilling

Science.gov (United States)

Ren, Shaoran; Liu, Yanmin; Gong, Zhiwu; Yuan, Yujie; Yu, Lu; Wang, Yanyong; Xu, Yan; Deng, Junyu

2018-02-01

In this study, we applied a two-phase flow model to simulate water and sand blowout processes when penetrating shallow water flow (SWF) formations during deepwater drilling. We define `sand' as a pseudo-component with high density and viscosity, which can begin to flow with water when a critical pressure difference is attained. We calculated the water and sand blowout rates and analyzed the influencing factors from them, including overpressure of the SWF formation, as well as its zone size, porosity and permeability, and drilling speed (penetration rate). The obtained data can be used for the quantitative assessment of the potential severity of SWF hazards. The results indicate that overpressure of the SWF formation and its zone size have significant effects on SWF blowout. A 10% increase in the SWF formation overpressure can result in a more than 90% increase in the cumulative water blowout and a 150% increase in the sand blowout when a typical SWF sediment is drilled. Along with the conventional methods of well flow and pressure control, chemical plugging, and the application of multi-layer casing, water and sand blowouts can be effectively reduced by increasing the penetration rate. As such, increasing the penetration rate can be a useful measure for controlling SWF hazards during deepwater drilling.

Initial response of a rock penetrator

International Nuclear Information System (INIS)

Longcope, D.B.; Grady, D.E.

1977-12-01

An analysis based on elastic rod theory is given for the early-time axisymmetric response of pointed penetrators. Results of measurements by laser interferometry of the back surface particle velocity of laboratory scale penetrators impacted by sandstone targets are presented. Values of the initial pressure on the penetrator tip are determined which give good agreement between the analytical and experimental results. These initial tip pressures are found to be approximated by the stress-particle velocity Hugoniot for the target material

Evaporation Limited Radial Capillary Penetration in Porous Media.

Science.gov (United States)

Liu, Mingchao; Wu, Jian; Gan, Yixiang; Hanaor, Dorian A H; Chen, C Q

2016-09-27

The capillary penetration of fluids in thin porous layers is of fundamental interest in nature and various industrial applications. When capillary flows occur in porous media, the extent of penetration is known to increase with the square root of time following the Lucas-Washburn law. In practice, volatile liquid evaporates at the surface of porous media, which restricts penetration to a limited region. In this work, on the basis of Darcy's law and mass conservation, a general theoretical model is developed for the evaporation-limited radial capillary penetration in porous media. The presented model predicts that evaporation decreases the rate of fluid penetration and limits it to a critical radius. Furthermore, we construct a unified phase diagram that describes the limited penetration in an annular porous medium, in which the boundaries of outward and inward liquid are predicted quantitatively. It is expected that the proposed theoretical model will advance the understanding of penetration dynamics in porous media and facilitate the design of engineered porous architectures.

Non-penetrating filtration surgery versus trabeculectomy for open-angle glaucoma.

Science.gov (United States)

Eldaly, Mohamed A; Bunce, Catey; Elsheikha, Ola Z; Wormald, Richard

2014-02-15

Glaucoma is the second commonest cause of blindness worldwide. Non-penetrating glaucoma surgeries have been developed as a safer and more acceptable surgical intervention to patients compared to conventional procedures. To compare the effectiveness of non-penetrating trabecular surgery compared with conventional trabeculectomy in people with glaucoma. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 8), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to September 2013), EMBASE (January 1980 to September 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to September 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 27 September 2013. This review included relevant randomised controlled trials (RCTs) and quasi-RCTs on participants undergoing standard trabeculectomy for open-angle glaucoma compared to non-penetrating surgery, specifically viscocanalostomy or deep sclerectomy, with or without adjunctive measures. Two review authors independently reviewed the titles and abstracts of the search results. We obtained full copies of all potentially eligible studies and assessed each one according to the definitions in the 'Criteria for considering studies' section of this review. We used standard methodological procedures expected by The Cochrane Collaboration. We included five studies with a total of 311 eyes (247 participants) of which 133 eyes (participants) were quasi-randomised. One hundred and sixty eyes which had trabeculectomy were compared to 151 eyes that had non-penetrating

Potential of the octanol-water partition coefficient (logP) to predict the dermal penetration behaviour of amphiphilic compounds in aqueous solutions.

Science.gov (United States)

Korinth, Gintautas; Wellner, Tanja; Schaller, Karl Heinz; Drexler, Hans

2012-11-23

Aqueous amphiphilic compounds may exhibit enhanced skin penetration compared with neat compounds. Conventional models do not predict this percutaneous penetration behaviour. We investigated the potential of the octanol-water partition coefficient (logP) to predict dermal fluxes for eight compounds applied neat and as 50% aqueous solutions in diffusion cell experiments using human skin. Data for seven other compounds were accessed from literature. In total, seven glycol ethers, three alcohols, two glycols, and three other chemicals were considered. Of these 15 compounds, 10 penetrated faster through the skin as aqueous solutions than as neat compounds. The other five compounds exhibited larger fluxes as neat applications. For 13 of the 15 compounds, a consistent relationship was identified between the percutaneous penetration behaviour and the logP. Compared with the neat applications, positive logP were associated with larger fluxes for eight of the diluted compounds, and negative logP were associated with smaller fluxes for five of the diluted compounds. Our study demonstrates that decreases or enhancements in dermal penetration upon aqueous dilution can be predicted for many compounds from the sign of logP (i.e., positive or negative). This approach may be suitable as a first approximation in risk assessments of dermal exposure. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

The market penetration of energy-efficiency programs

Energy Technology Data Exchange (ETDEWEB)

Berry, L.

1990-04-01

The focus of this report is on one source of resource planning uncertainty: the expected market penetration of DSM (Demand Site Management) programs. Its purpose is to help refine planning assumptions and reduce uncertainty about the market penetration of utility DSM programs by: (1) investigating concepts and definitions of market penetration, (2) reviewing data that characterize patterns of variation (including ranges, averages and maximum levels) in program participation rates, (3) identifying the factors that affect participation, and (4) reviewing the structure and data requirements of models that forecast market penetration. 84 refs., 14 figs., 16 tabs.

Real-Time Penetrating Particle Analyzer (PAN)

Science.gov (United States)

Wu, X.; Ambrosi, G.; Bertucci, B.

2018-02-01

The PAN can measure penetrating particles with great precision to study energetic particles, solar activities, and the origin and propagation of cosmic rays. The real-time monitoring of penetrating particles is crucial for deep space human travel.

Control of penetration zone GMAW

Directory of Open Access Journals (Sweden)

Віталій Петрович Iванов

2016-11-01

Full Text Available Thermal properties of the base metal, shielding medium and the nature of the electrode metal transfer to a great extent determine the penetration area formation in gas-arc welding. It is not always possible to take into account the influence of these factors on penetration front forming within the existing models. The aim of the work was to research the penetration area forming in gas-arc welding. The research of the penetration area forming in gas-arc welding of CrNi austenitic steels was made. The parameters of the regime as well as the kind of the gaseous medium influence on the formation of the penetration zone were studied. The article shows a linear proportional relationship between the electrode feed rate and the size of the base metal plate. The penetration area formation mode for welding in argon and carbon dioxide have been worked out. Diameter, feed rate and the speed of the electrode movement have been chosen as the main input parameters. Multiple regression analysis method was used to make up the modes. The relations of the third order that make it possible to take into account the electrode metal transfer and thermal properties change of the materials to be welded were used. These relationships show quite good agreement with the experimental measurements in the calculation of the fusion zone shape with consumable electrode in argon and carbon dioxide. It was determined that the shape of the melting front curve can be shown as a generalized function in which the front motion parameters depend on feed rate and the diameter of the electrode. Penetration zone growth time is determined by the welding speed and is calculated as a discrete function of the distance from the electrode with the spacing along the movement coordinate. The influence of the mode parameters on the formation of the fusion zone has been investigated and the ways to manage and stabilize the weld pool formation have been identified. The modes can be used to develop

Re-engineering therapeutic antibodies for Alzheimer's disease as blood-brain barrier penetrating bi-specific antibodies.

Science.gov (United States)

Pardridge, William M

2016-12-01

Therapeutic antibodies are large molecule drugs that do not cross the blood-brain barrier (BBB). Therefore, drug development of therapeutic antibodies for Alzheimer's disease (AD) requires that these molecules be re-engineered to enable BBB delivery. This is possible by joining the therapeutic antibody with a transporter antibody, resulting in the engineering of a BBB-penetrating bispecific antibody (BSA). Areas covered: The manuscript covers transporter antibodies that cross the BBB via receptor-mediated transport systems on the BBB, such as the insulin receptor or transferrin receptor. Furthermore, it highlights therapeutic antibodies for AD that target the Abeta amyloid peptide, beta secretase-1, or the metabotropic glutamate receptor-1. BSAs are comprised of both the transporter antibody and the therapeutic antibody, as well as IgG constant region, which can induce immune tolerance or trigger transport via Fc receptors. Expert opinion: Multiple types of BSA molecular designs have been used to engineer BBB-penetrating BSAs, which differ in valency and spatial orientation of the transporter and therapeutic domains of the BSA. The plasma pharmacokinetics and dosing regimens of BSAs differ from that of conventional therapeutic antibodies. BBB-penetrating BSAs may be engineered in the future as new treatments of AD, as well as other neural disorders.

Development of penetrant materials from used oil

International Nuclear Information System (INIS)

Mohamad Pauzi Ismail; Azhar Azmi

2014-01-01

This paper described the results of experiment to produce penetrant for nondestructive testing using used engine oil. The used engine oil was obtained from motor vehicle. It was mixed with kerosene at several mix proportion. The penetrability of these mixing were measured and compared with the penetrant available on the market. The results of measurement were explained and discussed. (author)

Microwave heat treatment as a substitute for conventional treatment of palm oil fruits

International Nuclear Information System (INIS)

Mujahid H Al-Fayadh; Nor Azura Masabbir Ali

1996-01-01

Microwave energy has become a sound method of heat treatment because of its high penetration power, cleanliness and possible economic significance. In this research, microwave heat was used as a substitute for conventional blanching method of palm oil fruits. Microwave treatment at 2450 MHz and 800 watts gave very close color and frn,frying characteristics to oil of blanched fruits after one minute exposure time. However, five minutes of microwave heat gave severe husk oil discoloration after 49 hours of deep frying, compared to all oils extracted from fruits treated by either low, microwave exposure time or conventional steam treatment. Kernel oil, after five minutes of microwave treatment, was less discolored than both steam or microwave-treated fruits for one minute. More carotenes and discoloration compounds may be contributed to discoloration during microwave treatments. Oil chemical constants of both husk and kernel oils treated by microwave heat were close to those treated by conventional heat. Further research is needed to investigate detailed oil characteristics and evaluate the feasibility study for using microwave energy, as a substitute for conventional heat in palm oil industry

Two methodologies for physical penetration testing using social engineering

NARCIS (Netherlands)

Dimkov, T.; van Cleeff, A.; Pieters, Wolter; Hartel, Pieter H.

2010-01-01

Penetration tests on IT systems are sometimes coupled with physical penetration tests and social engineering. In physical penetration tests where social engineering is allowed, the penetration tester directly interacts with the employees. These interactions are usually based on deception and if not

Assessing the credibility of diverting through containment penetrations

International Nuclear Information System (INIS)

Cooley, J.N.; Swindle, D.W. Jr.

1980-01-01

A viable approach has been developed for identifying those containment penetrations in a nuclear fuel reprocessing plant which are credible diversion routes. The approach is based upon systematic engineering and design analyses and is applied to each type of penetration to determine which penetrations could be utilized to divert nuclear material from a reprocessing facility. The approach is described and the results of an application are discussed. In addition, the concept of credibility is developed and discussed. For a typical reprocessing plant design, the number of penetrations determined to be credible without process or piping modifications was approx. 16% of the penetrations originally identified

The influence of distributed generation penetration levels on energy markets

International Nuclear Information System (INIS)

Vahl, Fabrício Peter; Rüther, Ricardo; Casarotto Filho, Nelson

2013-01-01

Planning of national energy policies brings new dilemmas with the introduction of distributed generators (DG). Economic theory suggests that a perfectly competitive market would lead to efficient pricing. In the absence of competition, regulators play a fundamental role in attracting reasonably priced finance in order to maintain, refurbish and increase the infrastructure and provide services at a reasonable cost. Energy market price equilibrium is mainly dependent on suppliers, generators, energy sources and demand, represented by conventional utility grid users. Its behavior is similar to that of other commodities. As generation becomes less centralized with the increasing economic viability of renewable energy sources, new suppliers are being connected to the grid. Such evolution means the transition from a monopolistic market to a broader and more open environment, with an increasing number of competitors. We make use of variational inequalities to model a hypothetical DG market in different scenarios, from monopoly, to oligopoly, to open market. Such an approach enables different equilibrium outcomes due to different DG penetration levels. Based on these findings, we argue that energy policies for such markets must be developed according to each specific stage of the grid's lifecycle. We show how energy policies and market regulations may affect such a transition, which may be catastrophic if not managed properly, and which is dependent on the energy mix. -- Highlights: •DG affects energy markets depending on technologies, penetration and infrastructure. •Energy prices vary when the market moves from centralized to several suppliers. •Variational inequalities are presented to simulate a market under such transitions. •The increase of DG penetration level may present different energy prices variation. •If technical and political issues of smart grids are not improved, markets may crash

Quasi-relativistic effects in barrier-penetration processes

International Nuclear Information System (INIS)

Anchishkin, D.V.

1991-01-01

The problem of a particle tunneling through the potential barrier is solved within quasi-relativistic Schroedinger equation. It is shown that the subbarrier relativistic effects give a significant addition to penetration coefficient when some relations between parameters of the barrier and mass of a tunneling particle are satisfied. For instance an account of these effects for penetration of low energy π + -mesons through Coulomb barrier of the 298 U nuclei would give the increasing of penetration coefficient to 30 percent as compared to the nonrelativistic one. Also we give the criteria under which the contribution of the ''under barrier relativism'' to penetration coefficient becomes essential. 3 refs.; 6 figs. (author)

Retrospective study of penetrating keratoplasty at the Santa Casa of Porto Alegre

OpenAIRE

Fabris, Caroline; Corrêa, Zélia Maria S.; Marcon, Alexandre S.; Castro, Terla Nunes de; Marcon, Ítalo Mundialino; Pawlowski, Cristiane

2001-01-01

Objetivos: Traçar o perfil clínico e social dos pacientes submetidos a transplante de córnea e avaliar as principais indicações desses transplantes, tempo de espera para doação e os índices de sucesso, rejeição e falência dos transplantes penetrantes de córnea. Métodos: Foram analisados retrospectivamente os prontuários de 87 pacientes submetidos a transplante penetrante de córnea no Serviço de Oftalmologia da Santa Casa de Porto Alegre entre janeiro de 1990 e dezembro de 1998, totalizando 91...

Long-Term Functional and Anatomical Outcome after Descemet Stripping Automated Endothelial Keratoplasty: A Prospective Single-Center Study

Directory of Open Access Journals (Sweden)

Jeroen van Rooij

2018-01-01

Full Text Available Purpose. To investigate the long-term anatomical and functional outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK. Methods. Prospective follow-up of 114 eyes (95 subjects after DSAEK for endothelial dysfunction. Measurements included best spectacle-corrected visual acuity (BSCVA, straylight, endothelial cell density (ECD, and graft thickness. Results. The mean follow-up time was 5.1 ± 1.5 years. Four grafts ultimately failed (after 5 to 7 years. From baseline up to 1 year after DSAEK, mean BSCVA improved by 0.30 logMAR. This beneficial effect remained until the last follow-up (LFU. After DSAEK, straylight was reduced. ECD sharply dropped by 900 cells/mm2 (33% immediately after surgery and, thereafter, steadily decreased at a rate of 11 cells/mm2 per month. No significant correlation was observed between graft thickness at 3 years and BSCVA. Conclusions. We observed a low graft failure rate and a normalization of graft thickness. Postoperative straylight remained elevated relative to the normal population. The sharp initial and the subsequent more gradual ECD decline are consistent with other studies. A significant and prolonged functional gain can be achieved by posterior lamellar grafting for endothelial dysfunction.

Principais indicações de transplante penetrante de córnea em um serviço de referência no interior de São Paulo (Sorocaba - SP, Brasil Major indications for corneal penetrating keratoplasty at a reference service in São Paulo state (Sorocaba - SP, Brazil

Directory of Open Access Journals (Sweden)

Miguel José Calix Netto

2006-10-01

: São Paulo (68%, Minas Gerais (6%, Paraná (6%, Rio de Janeiro (5%, Maranhão (3% and others (12%. The main indications: keratoconus 65%, pseudophakic bullous keratopathy 21%, corneal scarring 10%, Fuchs dystrophy 1.9%, lattice dystrophy 0.9% and Stevens-Johnson syndrome 0.9%. CONCLUSION: Many patients referred to corneal transplantation had no indication for such procedure. This fact demonstrates the poor knowledge of general ophthalmologists about the real indications of penetrating keratoplasty. Keratoconus was the major indication followed by pseudophakic bullous keratopathy.

Thyroid Emphysema Following Penetrating Neck Trauma

Directory of Open Access Journals (Sweden)

Demet Karadağ

2011-03-01

Full Text Available Although traumatic thyroid gland rupture or hemorrhage is usually seen in goitrous glands, injuries of the normal thyroid gland after neck trauma have rarely been described in the literature. We describe a 44-year-old man who presented with thyroid emphysema and subcutaneous emphysema (SCE that occurred after penetrating neck trauma. CT images showed complete resolution of thyroid emphysema and subcutaneous emphysema at follow-up examination. Neck injuries can be life threatening. After penetrating neck traumas, physicians should consider subtle esophageal or tracheal laceration. Thyroid emphysema can occur as the result of penetrating neck trauma. The mechanism of emphysema of the thyroid parenchyma can be explained by the thyroid gland’s presence in a single visceral compartment that encompasses the larynx, trachea and thyroid gland. We describe an unusual case of thyroid emphysema of a normal thyroid gland following a penetrating neck injury.

Compound antimalarial ethosomal cataplasm: preparation, evaluation, and mechanism of penetration enhancement.

Science.gov (United States)

Shen, Shuo; Liu, Shu-Zhi; Zhang, Yu-Shi; Du, Mao-Bo; Liang, Ai-Hua; Song, Li-Hua; Ye, Zu-Guang

2015-01-01

Malaria is still a serious public health problem in some parts of the world. The problems of recurrence and drug resistance are increasingly more serious. Thus, it is necessary to develop a novel antimalarial agent. The objectives of this study were to construct a novel compound antimalarial transdermal nanosystem-ethosomal cataplasm, to investigate its characteristics and efficiency, and to systematically explore the penetration-enhancing mechanisms of ethosomal cataplasm. Artesunate-loaded ethosomes and febrifugine-loaded ethosomes were prepared, and their characteristics were evaluated. Drug-loaded ethosomes were incorporated in the matrix of cataplasm to form the compound antimalarial ethosomal cataplasm. With the help of ethosomal technology, the accumulated permeation quantity of artesunate significantly increased at 8 hours after administration, which was 1.57 times as much as that of conventional cataplasm. Soon after administration, the ethosomal cataplasm could make a large quantity of antimalarial drug quickly penetrate through skin, then the remaining drug in the ethosomal cataplasm could be steadily released. These characteristics of ethosomal cataplasm are favorable for antimalarial drugs to kill Plasmodium spp. quickly and prevent the resurgence of Plasmodium spp. As expected, the ethosomal cataplasm showed good antimalarial efficiency in this experiment. The negative conversion rates were 100% and the recurrence rates were 0% at all dosages. The mechanism of penetration enhancement of the ethosomal cataplasm was systematically explored using an optics microscope, polarization microscope, and transmission electron microscopy. The microstructure, ultrastructure, and birefringent structure in skin were observed. Data obtained in this study showed that the application of ethosomal technology to antimalarial cataplasm could improve the transdermal delivery of drug, enhance the efficacy, and facilitate practical application in clinic.

Crack growth rates in vessel head penetration materials

International Nuclear Information System (INIS)

Gomez Briceno, D.; Lapena, J.; Blazquez, F.

1994-01-01

The cracks detected in reactor vessel head penetrations in certain European plants have been attributed to Primary Water Stress Corrosion Cracking (PWSCC). The penetrations in question are made from Inconel 600. The susceptibility of this alloy to PWSCC has been widely studied in relation to use of this material for steam generator tubes. When the first reactor vessel head penetration cracks were detected, most of the available data on crack propagation rates were from test specimens made from steam generator tubes and tested under conditions that questioned the validity of these data for assessment of the evolution of cracks in penetrations. For this reason, the scope of the Spanish Research Project on the Inspection and Repair of PWR reactor vessel head penetrations included the acquisition of data on crack propagation rates in Inconel 600, representative of the materials used for vessel head penetrations. (authors). 1 fig., 2 tabs., 6 refs

Quantitative Analysis of Endothelial Cell Loss in Preloaded Descemet Membrane Endothelial Keratoplasty Grafts.

Science.gov (United States)

Wolle, Meraf A; DeMill, David L; Johnson, Lauren; Lentz, Stephen I; Woodward, Maria A; Mian, Shahzad I

2017-11-01

Availability of preloaded Descemet membrane endothelial keratoplasty (pDMEK) tissue may increase acceptance of DMEK in surgical management of endothelial disease. The goal of this study was to determine the safety of pDMEK grafts for 24 hours before surgery by analyzing endothelial cell loss (ECL) using 2 image analysis software programs. A total of 18 cadaveric corneas were prepared for DMEK using a standardized technique and loaded in a modified Jones tube injector. Nine of the corneas were injected into Calcein AM vital dye after 1 minute (controls), and the remaining 9 corneas were left preloaded for 24 hours before injection into vital dye for staining. The stained corneas were imaged using an inverted confocal microscope. ECL was then analyzed and quantified by 2 different graders using 2 image analysis software programs. The control DMEK tissue resulted in 22.0% ± 4.0% ECL compared with pDMEK tissue, which resulted in 19.2% ± 7.2% ECL (P = 0.31). Interobserver agreement was 0.93 for MetaMorph and 0.92 for Fiji. The average time required to process images with MetaMorph was 2 ± 1 minutes and with Fiji was 20 ± 10 minutes. Intraobserver agreement was 0.97 for MetaMorph and 0.93 for Fiji. Preloading DMEK tissue is safe and may provide an alternative technique for tissue distribution and surgery for DMEK. The use of MetaMorph software for quantifying ECL is a novel and accurate imaging method with increased efficiency and reproducibility compared with the previously validated Fiji.

Measurement of the London penetration depths in YBa2Cu3Ox by means of muon spin rotation (μ SR) experiments

International Nuclear Information System (INIS)

Pumpin, B.; Keller, H.; Kundig, W.; Odermatt, W.; Savic, I.M.; Schneider, J.W.; Simmler, H.; Zimmermann, P.

1989-01-01

The authors report on experiments conducted to get accurate values of the London penetration depths in YBa 2 Cu 3 O x , μSR measurements were performed on a high quality, sintered sample and a c-axis-oriented polycrystal. For the sintered sample the temperature dependence of the effective penetration depthλ eff is well described by the two-fluid model, withλ eff (0) = 155(10) nm. This behavior ofλ eff (T) is consistent with conventional s-wave pairing. The anisotropy ratioλ c /λ ab ≅5(1) was determined from measurements on the polycrystal. These results were used to calculateλ ab (0) = 130(10) nm andλ c (0)≅ 500-800 nm

Penetration of Photovoltaics in Greece

OpenAIRE

Eugenia Giannini; Antonia Moropoulou; Zacharias Maroulis; Glykeria Siouti

2015-01-01

Recently, an interesting experiment was completed in Greece concerning photovoltaic penetration into the electricity production sector. Based on the relevant laws and in accordance to the related European directives, an explosive penetration process was completed in less than three years, resulting in a 7% share of photovoltaics in electricity production instead of the previous negligible share. The legislation was based on licensing simplification and generous feed-in-tariffs. This approach ...

Recursive Monte Carlo method for deep-penetration problems

International Nuclear Information System (INIS)

Goldstein, M.; Greenspan, E.

1980-01-01

The Recursive Monte Carlo (RMC) method developed for estimating importance function distributions in deep-penetration problems is described. Unique features of the method, including the ability to infer the importance function distribution pertaining to many detectors from, essentially, a single M.C. run and the ability to use the history tape created for a representative region to calculate the importance function in identical regions, are illustrated. The RMC method is applied to the solution of two realistic deep-penetration problems - a concrete shield problem and a Tokamak major penetration problem. It is found that the RMC method can provide the importance function distributions, required for importance sampling, with accuracy that is suitable for an efficient solution of the deep-penetration problems considered. The use of the RMC method improved, by one to three orders of magnitude, the solution efficiency of the two deep-penetration problems considered: a concrete shield problem and a Tokamak major penetration problem. 8 figures, 4 tables

penetrating abdominal trauma

African Journals Online (AJOL)

gender, mechanism of injury, injury severity scores (ISS), penetrating ... ileus, reduced pulmonary function and loss of muscle mass and function, all of .... pathophysiology and rehabilitation. ... quality of life after surgery for colorectal cancer.

Optimized support vector regression for drilling rate of penetration estimation

Science.gov (United States)

Bodaghi, Asadollah; Ansari, Hamid Reza; Gholami, Mahsa

2015-12-01

In the petroleum industry, drilling optimization involves the selection of operating conditions for achieving the desired depth with the minimum expenditure while requirements of personal safety, environment protection, adequate information of penetrated formations and productivity are fulfilled. Since drilling optimization is highly dependent on the rate of penetration (ROP), estimation of this parameter is of great importance during well planning. In this research, a novel approach called `optimized support vector regression' is employed for making a formulation between input variables and ROP. Algorithms used for optimizing the support vector regression are the genetic algorithm (GA) and the cuckoo search algorithm (CS). Optimization implementation improved the support vector regression performance by virtue of selecting proper values for its parameters. In order to evaluate the ability of optimization algorithms in enhancing SVR performance, their results were compared to the hybrid of pattern search and grid search (HPG) which is conventionally employed for optimizing SVR. The results demonstrated that the CS algorithm achieved further improvement on prediction accuracy of SVR compared to the GA and HPG as well. Moreover, the predictive model derived from back propagation neural network (BPNN), which is the traditional approach for estimating ROP, is selected for comparisons with CSSVR. The comparative results revealed the superiority of CSSVR. This study inferred that CSSVR is a viable option for precise estimation of ROP.

Image-guided modified deep anterior lamellar keratoplasty (DALK) corneal transplant using intraoperative optical coherence tomography

Science.gov (United States)

Tao, Yuankai K.; LaBarbera, Michael; Ehlers, Justis P.; Srivastava, Sunil K.; Dupps, William J.

2015-03-01

Deep anterior lamellar keratoplasty (DALK) is an alternative to full-thickness corneal transplant and has advantages including the absence of allograft rejection; shortened duration of topical corticosteroid treatment and reduced associated risk of glaucoma, cataract, or infection; and enables use of grafts with poor endothelial quality. DALK begins by performing a trephination of approximately 80% stromal thickness, as measured by pachymetry. After removal of the anterior stoma, a needle is inserted into the residual stroma to inject air or viscoelastic to dissect Descemet's membrane. These procedures are inherently difficult and intraoperative rates of Descemet's membrane perforation between 4-39% have been reported. Optical coherence tomography (OCT) provides high-resolution images of tissue microstructures in the cornea, including Descemet's membrane, and allows quantitation of corneal layer thicknesses. Here, we use crosssectional intraoperative OCT (iOCT) measurements of corneal thickness during surgery and a novel micrometeradjustable biopsy punch to precision-cut the stroma down to Descemet's membrane. Our prototype cutting tool allows us to establish a dissection plane at the corneal endothelium interface, mitigates variability in cut-depths as a result of tremor, reduces procedure complexity, and reduces complication rates. iOCT-guided modified DALK procedures were performed on 47 cadaveric porcine eyes by non-experts and achieved a perforation rate of ~5% with a mean corneal dissection time care.

Nomogram to Predict Graft Thickness in Descemet Stripping Automated Endothelial Keratoplasty: An Eye Bank Study.

Science.gov (United States)

Bae, Steven S; Menninga, Isaac; Hoshino, Richard; Humphreys, Christine; Chan, Clara C

2018-06-01

The purpose of this study was to develop a nomogram to predict postcut thickness of corneal grafts prepared at an eye bank for Descemet stripping automated endothelial keratoplasty (DSAEK). Retrospective chart review was performed of DSAEK graft preparations by 3 experienced technicians from April 2012 to May 2017 at the Eye Bank of Canada-Ontario Division. Variables collected included the following: donor demographics, death-to-preservation time, death-to-processing time, precut tissue thickness, postcut tissue thickness, microkeratome head size, endothelial cell count, cut technician, and rate of perforation. Linear regression models were generated for each microkeratome head size (300 and 350 μm). A total of 780 grafts were processed during the study period. Twelve preparation attempts resulted in perforation (1.5%) and were excluded. Mean precut tissue thickness was 510 ± 49 μm (range: 363-670 μm). Mean postcut tissue thickness was 114 ± 22 μm (range: 57-193 μm). Seventy-nine percent (608/768) of grafts were ≤130 μm. The linear regression models included precut thickness and donor age, which were able to predict the thickness to within 25 μm 80% of the time. We report a nomogram to predict thickness of DSAEK corneal grafts prepared in an eye bank setting, which was accurate to within 25 μm 80% of the time. Other eye banks could consider performing similar analyses.

Characterization of nuclear reactor containment penetrations. Preliminary report

International Nuclear Information System (INIS)

Bump, T.R.; Seidensticker, R.W.; Shackelford, M.A.; Gambhir, V.K.; McLennan, G.L.

1984-06-01

This report summarizes the survey work conducted by Argonne National Laboratory on the design and details of major penetrations in 22 nuclear power plants. The survey includes all containment types and materials in current use. It also includes details of all types of penetrations (except for electrical penetration assemblies and valves) and the seals and gaskets used in them. The report provides a test matrix for testing major penetrations and for testing seals and gaskets in order to evaluate their leakage potential under severe accident conditions

40 CFR 1065.365 - Nonmethane cutter penetration fractions.

Science.gov (United States)

2010-07-01

... fractions. 1065.365 Section 1065.365 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Measurements § 1065.365 Nonmethane cutter penetration fractions. (a) Scope and frequency. If you use a FID... penetration fractions of methane, PFCH4, and ethane, PF C2H6. As detailed in this section, these penetration...

The penetration of aerosols through fine orifices

International Nuclear Information System (INIS)

Marshall, I.A.; Latham, L.J.; Ball, M.H.E.; Mitchell, J.P.

1991-07-01

A novel experimental technique has been extended to study the migration of gas-borne glass microspheres in the size range from about 1 to 15 μm volume equivalent diameter through orifices with bores and thicknesses in the range from 2 to 100 μm and 12.7 to 509 μm respectively. The penetration of these particles was significant with all orifices greater than 10 μm bore at a constant driving pressure of 100 kPa. However, few particles penetrated the 5 μm bore orifice, while virtually no particles penetrated the 2 μm bore orifice. Particle size distributions determined after penetration through the orifices were very similar to that of the upstream aerosol except when significant attenuation occurred. (author)

Temporary fire sealing of penetrations on TFTR

International Nuclear Information System (INIS)

Hondorp, H.L.

1981-02-01

The radiation shielding provided for TFTR for D-D and D-T operation will be penetrated by numerous electrical and mechanical services. Eventually, these penetrations will have to be sealed to provide the required fire resistance, tritium sealability, pressure integrity and radiation attenuation. For the initial hydrogen operation, however, fire sealing of the penetrations in the walls and floor is the primary concern. This report provides a discussion of the required and desirable properties of a temporary seal which can be used to seal these penetrations for the hydrogen operation and then subsequently be removed and replaced as required for the D-D and D-T operations. Several candidate designs are discussed and evaluated and recommendations are made for specific applications

Miniature Ground Penetrating Radar, CRUX GPR

Science.gov (United States)

Kim, Soon Sam; Carnes, Steven R.; Haldemann, Albert F.; Ulmer, Christopher T.; Ng, Eddie; Arcone, Steven A.

2006-01-01

Under NASA instrument development programs (PIDDP 2000-2002, MIPD 2003-2005, ESR and T, 2005) we have been developing miniature ground penetrating radars (GPR) for use in mapping subsurface stratigraphy from planetary rovers for Mars and lunar applications. The Mars GPR is for deeper penetration (up to 50 m depth) into the Martian subsurface at moderate resolution (0.5 m) for a geological characterization. As a part of the CRUX (Construction and Resource Utilization Explorer) instrument suite, the CRUX GPR is optimized for a lunar prospecting application. It will have shallower penetration (5 m depth) with higher resolution (10 cm) for construction operations including ISRU (in-situ resource utilization).

Building virtual pentesting labs for advanced penetration testing

CERN Document Server

Cardwell, Kevin

2014-01-01

Written in an easy-to-follow approach using hands-on examples, this book helps you create virtual environments for advanced penetration testing, enabling you to build a multi-layered architecture to include firewalls, IDS/IPS, web application firewalls, and endpoint protection, which is essential in the penetration testing world. If you are a penetration tester, security consultant, security test engineer, or analyst who wants to practice and perfect penetration testing skills by building virtual pen testing labs in varying industry scenarios, this is the book for you. This book is ideal if yo

Uneventful Anterior Migration of Intravitreal Ozurdex Implant in a Patient with Iris-Sutured Intraocular Lens and Descemet Stripping Automated Endothelial Keratoplasty.

Science.gov (United States)

Zafar, Andleeb; Aslanides, Ioannis M; Selimis, Vasileios; Tsoulnaras, Konstantinos I; Tabibian, David; Kymionis, George D

2018-01-01

We report here the case of a patient with anterior segment migration of intravitreal dexamethasone implant as well as its management and outcome. The patient had the following sequence of events: complicated cataract surgery, iris-sutured intraocular lens implant, followed by cystoid macular edema treated with intravitreal Avastin, retinal vein occlusion treated with intravitreal dexamethasone implant, corneal decompensation treated with Descemet stripping automated endothelial keratoplasty (DSAEK), and finally recurrence of macular edema treated with repeated intravitreal dexamethasone implant. Dexamethasone implant had completely dissolved from the eye 12 weeks after insertion without any complication. A conservative approach with regular monitoring in the situation of a quiet anterior segment without any corneal decompensation can provide enough time for the implant to dissolve without causing any complication to the involved eye, avoiding any additional surgical intervention, as presented in this case report. Despite the fact that the implant was left for natural dissolution, there were no adverse effects related to the graft or the eye.

Chronic Disease Prevalence and Medicare Advantage Market Penetration

Science.gov (United States)

Bernell, Stephanie Lazarus; Casim, Faizan M.; Wilmott, Jennifer; Pearson, Lindsey; Byler, Caitlin M.; Zhang, Zidong

2015-01-01

By March 2015, 30% of all Medicare beneficiaries were enrolled in Medicare Advantage (MA) plans. Research to date has not explored the impacts of MA market penetration on individual or population health outcomes. The primary objective of this study is to examine the relationships between MA market penetration and the beneficiary’s portfolio of cardiometabolic diagnoses. This study uses 2004 to 2008 Medical Expenditure Panel Survey (MEPS) Household Component data to construct an aggregate index that captures multiple diagnoses in one outcome measure (Chronic Disease Severity Index [CDSI]). The MEPS data for 8089 Medicare beneficiaries are merged with MA market penetration data from Centers for Medicare and Medicaid Services (CMS). Ordinary least squares regressions are run with SAS 9.3 to model the effects of MA market penetration on CDSI. The results suggest that each percentage increase in MA market penetration is associated with a greater than 2-point decline in CDSI (lower burden of cardiometabolic chronic disease). Spill-over effects may be driving improvements in the cardiometabolic health of beneficiary populations in counties with elevated levels of MA market penetration. PMID:28462266

Thermo-chemical Ice Penetrator for Icy Moons

Science.gov (United States)

Arenberg, J. W.; Lee, G.; Harpole, G.; Zamel, J.; Sen, B.; Ross, F.; Retherford, K. D.

2016-12-01

The ability to place sensors or to take samples below the ice surface enables a wide variety of potential scientific investigations. Penetrating an ice cap can be accomplished via a mechanical drill, laser drill, kinetic impactor, or heated penetrator. This poster reports on the development of technology for the latter most option, namely a self-heated probe driven by an exothermic chemical reaction: a Thermo-chemical ice penetrator (TChIP). Our penetrator design employs a eutectic mix of alkali metals that produce an exothermic reaction upon contact with an icy surface. This reaction increases once the ice starts melting, so no external power is required. This technology is inspired by a classified Cold-War era program developed at Northrop Grumman for the US Navy. Terrestrial demonstration of this technology took place in the Arctic; however, this device cannot be considered high TRL for application at the icy moons of the solar system due to the environmental differences between Earth's Arctic and the icy moons. These differences demand a TChIP design specific to these cold, low mass, airless worlds. It is expected that this model of TChIP performance will be complex, incorporating all of the forces on the penetrator, gravity, the thermo-chemistry at the interface between penetrator and ice, and multi-phase heat and mass transport, and hydrodynamics. Our initial efforts are aimed at the development of a validated set of tools and simulations to predict the performance of the penetrator for both the environment found on these icy moons and for a terrestrial environment. The purpose of the inclusion of the terrestrial environment is to aid in model validation. Once developed and validated, our models will allow us to design penetrators for a specific scientific application on a specific body. This poster discusses the range of scientific investigations that are enabled by TChIP. We also introduce the development plan to advance TChIP to the point where it can be

Penetration shielding applications of CYLSEC

International Nuclear Information System (INIS)

Dexheimer, D.T.; Hathaway, J.M.

1985-01-01

Evaluation of penetration and discontinuity shielding is necessary to meet 10CFR20 regulations for ensuring personnel exposures are as low as reasonably achievable (ALARA). Historically, those shielding evaluations have been done to some degree on all projects. However, many early plants used conservative methods due to lack of an economical computer code, resulting in costly penetration shielding programs. With the increased industry interest in cost effectively reducing personnel exposures to meet ALARA regulations and with the development of the CYLSEC gamma transport computer code at Bechtel, a comprehensive effort was initiated to reduce penetration and discontinuity shielding but still provide a prudent degree of protection for plant personnel from radiation streaming. This effort was more comprehensive than previous programs due to advances in shielding analysis technology and increased interest in controlling project costs while maintaining personnel exposures ALARA. Methodology and resulting cost savings are discussed

Development Of The Nuclear Optical Penetration

Science.gov (United States)

Inoue, K.; Koike, K.; Imada, Y.

1984-10-01

We have developed the nuclear optical penetration to be incorporated in the wall penetration of the shell to introduce a data transmission system using optical fibers into a nuclear power plant with a pressurized water reactor. Radiation-induced coloration in optical glass seriously affects transmission characteristics of optical fibers, whereas it has been revealed that the pure-silica core optical fiber without any dopant in the core has wide applicability in radiation fields thanks to its very low radiation-induced attenuation. The wall penetration of the shell should have airtightness and resistivity to heat, vibration, and pressure, let alone radiation, excellent enough to be invariable in data transmission efficiency even when subjected to severe environmental tests. The sealing modules of this newly developed nuclear optical penetration are hermetically sealed. The gap between the optical fiber rod (100 pm in core diameter and 5 mm in rod diameter) and stainless steel tube is sealed with lamingted glass layer. As the result of He gas leakage test, high airtightness of less than 10 cc/sec was achieved. No thermal deformation of the core was caused by sealing with laminated glass layer, nor was observed transmission loss. Then the sealiing modules were subjected to the irradiation test using 60 Co gamma ray exposure of 2 x 10 rads. Though silica glass layer supporting the fiber rod and sealing glass portion turned blackish purple, transparency of the fiber was not affected. Only less than 0.5 dB of connecting loss was observed at the connecting point with the optical fiber cable. The sealing modules were also found to have resistivity to vibration and pressure as excellent as that of existing nuclear electric penetrations. We expect the nuclear optical fiber penetration will be much effective in improving reliability of data transmission systems using optical fibers in radiation fields.

Theory of activated penetrant diffusion in viscous fluids and colloidal suspensions

International Nuclear Information System (INIS)

Zhang, Rui; Schweizer, Kenneth S.

2015-01-01

We heuristically formulate a microscopic, force level, self-consistent nonlinear Langevin equation theory for activated barrier hopping and non-hydrodynamic diffusion of a hard sphere penetrant in very dense hard sphere fluid matrices. Penetrant dynamics is controlled by a rich competition between force relaxation due to penetrant self-motion and collective matrix structural (alpha) relaxation. In the absence of penetrant-matrix attraction, three activated dynamical regimes are predicted as a function of penetrant-matrix size ratio which are physically distinguished by penetrant jump distance and the nature of matrix motion required to facilitate its hopping. The penetrant diffusion constant decreases the fastest with size ratio for relatively small penetrants where the matrix effectively acts as a vibrating amorphous solid. Increasing penetrant-matrix attraction strength reduces penetrant diffusivity due to physical bonding. For size ratios approaching unity, a distinct dynamical regime emerges associated with strong slaving of penetrant hopping to matrix structural relaxation. A crossover regime at intermediate penetrant-matrix size ratio connects the two limiting behaviors for hard penetrants, but essentially disappears if there are strong attractions with the matrix. Activated penetrant diffusivity decreases strongly with matrix volume fraction in a manner that intensifies as the size ratio increases. We propose and implement a quasi-universal approach for activated diffusion of a rigid atomic/molecular penetrant in a supercooled liquid based on a mapping between the hard sphere system and thermal liquids. Calculations for specific systems agree reasonably well with experiments over a wide range of temperature, covering more than 10 orders of magnitude of variation of the penetrant diffusion constant

Hacking and penetration testing with low power devices

CERN Document Server

Polstra, Philip

2014-01-01

Hacking and Penetration Testing with Low Power Devices shows you how to perform penetration tests using small, low-powered devices that are easily hidden and may be battery-powered. It shows how to use an army of devices, costing less than you might spend on a laptop, from distances of a mile or more. Hacking and Penetration Testing with Low Power Devices shows how to use devices running a version of The Deck, a full-featured penetration testing and forensics Linux distribution, and can run for days or weeks on batteries due to their low power consumption. Author Philip Polstra shows how to

HMO penetration and the geographic mobility of practicing physicians.

Science.gov (United States)

Polsky, D; Kletke, P R; Wozniak, G D; Escarce, J J

2000-09-01

In this study, we assessed the influence of changes in health maintenance organization (HMO) penetration on the probability that established patient care physicians relocated their practices or left patient care altogether. For physicians who relocated their practices, we also assessed the impact of HMO penetration on their destination choices. We found that larger increases in HMO penetration decreased the probability that medical/surgical specialists in early career stayed in patient care in the same market, but had no impact on generalists, hospital-based specialists, or mid career medical/surgical specialists. We also found that physicians who relocated their practices were much more likely to choose destination markets with the same level of HMO penetration or lower HMO penetration compared with their origin markets than they were to choose destination markets with higher HMO penetration. The largely negligible impact of changes in HMO penetration on established physicians' decisions to relocate their practices or leave patient care is consistent with high relocation and switching costs. Relocating physicians' attraction to destination markets with the same level of HMO penetration as their origin markets suggests that, while physicians' styles of medical practice may adapt to changes in market conditions, learning new practice styles is costly.

Skin Penetration Enhancement by Natural Oils for Dihydroquercetin Delivery.

Science.gov (United States)

Čižinauskas, Vytis; Elie, Nicolas; Brunelle, Alain; Briedis, Vitalis

2017-09-12

Natural oils are commonly used in topical pharmaceutical formulations as emulsifiers, stabilizers or solubility enhancers. They are presented as safe and inert components, mainly used for formulation purposes. It is confirmed that natural oils can affect the skin penetration of various substances. Fatty acids are mainly responsible for this effect. Current understanding lacks reliable scientific data on penetration of natural oils into the skin and their skin penetration enhancement potential. In the current study, fatty acid content analysis was used to determine the principal fatty acids in soybean, olive, avocado, sea-buckthorn pulp, raspberry seed and coconut oils. Time of flight secondary ion mass spectrometry bioimaging was used to determine the distribution of these fatty acids in human skin ex vivo after application of the oils. Skin penetration enhancement ratios were determined for a perspective antioxidant compound dihydroquercetin. The results demonstrated skin penetration of fatty acids from all oils tested. Only soybean and olive oils significantly increased the skin distribution of dihydroquercetin and can be used as skin penetration enhancers. However, no correlation can be determined between the fatty acids' composition and skin penetration enhancement using currently available methodological approaches. This indicates that potential chemical penetration enhancement should be evaluated during formulation of topically applied products containing natural oils.

A Study on Factors Affecting Airborne LiDAR Penetration

Directory of Open Access Journals (Sweden)

Wei-Chen Hsu

2015-01-01

Full Text Available This study uses data from different periods, areas and parameters of airborne LiDAR (light detection and ranging surveys to understand the factors that influence airborne LiDAR penetration rate. A discussion is presented on the relationships between these factors and LiDAR penetration rate. The results show that the flight height above ground level (AGL does not have any relationship with the penetration rate. There are some factors that should have larger influence. For example, the laser is affected by a wet ground surface by reducing the number of return echoes. The field of view (FOV has a slightly negative correlation with the penetration rate, which indicates that the laser incidence angle close to zero should achieve the best penetration. The vegetation cover rate also shows a negative correlation with the penetration rate, thus bare ground and reduced vegetation in the aftermath of a typhoon also cause high penetration rate. More return echoes could be extracted from the full-waveform system, thereby effectively improving the penetration rate. This study shows that full-waveform LiDAR is an effective method for increasing the number of surface reflected echoes. This study suggests avoiding LiDAR survey employment directly following precipitation to prevent laser echo reduction.

Penetration Testing Professional Ethics: a conceptual model and taxonomy

Directory of Open Access Journals (Sweden)

Justin Pierce

2006-05-01

Full Text Available In an environment where commercial software is continually patched to correct security flaws, penetration testing can provide organisations with a realistic assessment of their security posture. Penetration testing uses the same principles as criminal hackers to penetrate corporate networks and thereby verify the presence of software vulnerabilities. Network administrators can use the results of a penetration test to correct flaws and improve overall security. The use of hacking techniques, however, raises several ethical questions that centre on the integrity of the tester to maintain professional distance and uphold the profession. This paper discusses the ethics of penetration testing and presents our conceptual model and revised taxonomy.

Chronic Disease Prevalence and Medicare Advantage Market Penetration

Directory of Open Access Journals (Sweden)

Steven W. Howard

2015-10-01

Full Text Available By March 2015, 30% of all Medicare beneficiaries were enrolled in Medicare Advantage (MA plans. Research to date has not explored the impacts of MA market penetration on individual or population health outcomes. The primary objective of this study is to examine the relationships between MA market penetration and the beneficiary’s portfolio of cardiometabolic diagnoses. This study uses 2004 to 2008 Medical Expenditure Panel Survey (MEPS Household Component data to construct an aggregate index that captures multiple diagnoses in one outcome measure (Chronic Disease Severity Index [CDSI]. The MEPS data for 8089 Medicare beneficiaries are merged with MA market penetration data from Centers for Medicare and Medicaid Services (CMS. Ordinary least squares regressions are run with SAS 9.3 to model the effects of MA market penetration on CDSI. The results suggest that each percentage increase in MA market penetration is associated with a greater than 2-point decline in CDSI (lower burden of cardiometabolic chronic disease. Spill-over effects may be driving improvements in the cardiometabolic health of beneficiary populations in counties with elevated levels of MA market penetration.

Radon penetration of concrete slab cracks, joints, pipe penetrations, and sealants

NARCIS (Netherlands)

Nielson, KK; Rogers, VC; Holt, RB; Pugh, TD; Grondzik, WA; deMeijer, RJ

1997-01-01

Radon movement through 12 test slabs with different cracks, pipe penetrations, cold joints, masonry blocks, sealants, and tensile stresses characterized the importance of these anomalous structural domains, Diffusive and advective radon transport were measured with steady-state air pressure

Sphere impact and penetration into wet sand

KAUST Repository

Marston, J. O.

2012-08-07

We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

Sphere impact and penetration into wet sand

KAUST Repository

Marston, J. O.; Vakarelski, Ivan Uriev; Thoroddsen, Sigurdur T

2012-01-01

We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

Penetrating eye injury in war.

Science.gov (United States)

Biehl, J W; Valdez, J; Hemady, R K; Steidl, S M; Bourke, D L

1999-11-01

The percentage of penetrating eye injuries in war has increased significantly in this century compared with the total number of combat injuries. With the increasing use of fragmentation weapons and possibly laser weapons on the battle-field in the future, the rate of eye injuries may exceed the 13% of the total military injuries found in Operations Desert Storm/Shield. During the Iran-Iraq War (1980-1988), eye injuries revealed that retained foreign bodies and posterior segment injuries have an improved prognosis in future military ophthalmic surgery as a result of modern diagnostic and treatment modalities. Compared with the increasing penetrating eye injuries on the battlefield, advances in ophthalmic surgery are insignificant. Eye armor, such as visors that flip up and down and protect the eyes from laser injury, needs to be developed. Similar eye protection is being developed in civilian sportswear. Penetrating eye injury in the civilian sector is becoming much closer to the military model and is now comparable for several reasons.

Corneal graft reversal: Histopathologic report of two cases.

Science.gov (United States)

Qahtani, Abdullah A; Alkatan, Hind M

2014-10-01

Graft reversal is a rare cause for failed PKP. In this case report we are presenting 2 graft failure cases in which the corneal grafts were reversed unintentionally. The onset of signs of graft failure, however was variable. We have included their clinical course and the histopathologic findings of the removed corneal grafts. A total of 6 cases including ours have been reported so far. The aim of this report is to attract the attention of corneal surgeons to an additional rare cause for failed penetrating keratoplasty (PKP) which is donor graft reversal.

Cracks on instrumentation penetrations in reactor vessel: a new challenge; Fissuration des penetrations de cuve: un nouveau defi

Energy Technology Data Exchange (ETDEWEB)

Anon

2004-02-01

In august 2003 NRC (nuclear regulatory commission) issued a warning concerning the deposits of boron acid that might accumulate on instrumental penetrations in the bottom of PWR vessels. These deposits were first detected on the David-Besse power plant and more recently on the unit 1 of South Texas Project (STP) during a refueling shutdown. STP contracted with the Areva company in order to perform inspections on all the 58 vessel penetrations of the unit 1 and to propose solutions. For that purpose the Areva company had to design a specific visual inspection tool that combined both ultra-sound method and Foucault current probing. The results of the inspection campaign on the unit 1 showed that only 2 penetration tubes were concerned with axial defects in their walls, that no circumferential defects were detected and that butt welds presented no cracks. The 2 incriminated penetration tubes were repaired: a section of both was replaced by an alloy-690 tube. (A.C.)

Going skin deep: A direct comparison of penetration potential of lipid-based nanovesicles on the isolated perfused human skin flap model.

Science.gov (United States)

Ternullo, Selenia; de Weerd, Louis; Holsæter, Ann Mari; Flaten, Gøril Eide; Škalko-Basnet, Nataša

2017-12-01

Phospholipid-based nanocarriers are attractive drug carriers for improved local skin therapy. In the present study, the recently developed isolated perfused human skin flap (IPHSF) model was used to directly compare the skin penetration enhancing potential of the three commonly used nanocarriers, namely conventional liposomes (CLs), deformable liposomes (DLs) and solid lipid nanoparticles (SLNs). Two fluorescent markers, calcein (hydrophilic) or rhodamine (lipophilic), were incorporated individually in the three nanosystems. The nanocarrier size ranged between 200 and 300nm; the surface charge and entrapment efficiency for both markers were dependent on the lipid composition and the employed surfactant. Both carrier-associated markers could not penetrate the full thickness human skin, confirming their suitability for dermal drug delivery. CLs exhibited higher retention of both markers on the skin surface compared to DLs and SLNs, indicating a depo formation. DLs and SLNs enabled the deeper penetration of the two markers into the skin layers. In vitro and ex vivo skin penetration studies performed on the cellophane membrane and full thickness pig/human skin, respectively, confirmed the findings. In conclusion, efficient dermal drug delivery can be achieved by optimization of a lipid nanocarrier on the suitable skin-mimicking model to assure system's accumulation in the targeted skin layer. Copyright © 2017 Elsevier B.V. All rights reserved.

Penetration Testing dan Analisis Kemanan Web Paud Dikmas

OpenAIRE

Giffari, Abizar

2018-01-01

Sebuah instansi atau perusahaan tentunya mempunyai data penting yang tersimpan dalam sebuah sistem database yang kuat dan aman untuk menghindari ancaman pencurian data dari pihak luar. Untuk mengukur sejauh mana tingkat keamanan yang dibuat, diperlukan sebuah metode pengetesan yang disebut Penetration Testing. Penetration Testing memungkinkan kita untuk dapat menentukan sejauh mana tingkat keamanan sistem yang di test. Penetration Testing juga memungkinkan kita menyerang sistem layaknya attac...

Quantitative penetration testing with item response theory

NARCIS (Netherlands)

Pieters, W.; Arnold, F.; Stoelinga, M.I.A.

2013-01-01

Existing penetration testing approaches assess the vulnerability of a system by determining whether certain attack paths are possible in practice. Therefore, penetration testing has thus far been used as a qualitative research method. To enable quantitative approaches to security risk management,

Penetrating ureteral trauma

Directory of Open Access Journals (Sweden)

Gustavo P. Fraga

2007-04-01

Full Text Available OBJECTIVE: The purpose of this series is to report our experience in managing ureteral trauma, focusing on the importance of early diagnosis, correct treatment, and the impact of associated injuries on the management and morbid-mortality. MATERIALS AND METHODS: From January 1994 to December 2002, 1487 laparotomies for abdominal trauma were performed and 20 patients with ureteral lesions were identified, all of them secondary to penetrating injury. Medical charts were analyzed as well as information about trauma mechanisms, diagnostic routine, treatment and outcome. RESULTS: All patients were men. Mean age was 27 years. The mechanisms of injury were gunshot wounds in 18 cases (90% and stab wounds in two (10%. All penetrating abdominal injuries had primary indication of laparotomy, and neither excretory urography nor computed tomography were used in any case before surgery. The diagnosis of ureteric injury was made intra-operatively in 17 cases (85%. Two ureteral injuries (10% were initially missed. All patients had associated injuries. The treatment was dictated by the location, extension and time necessary to identify the injury. The overall incidence of complications was 55%. The presence of shock on admission, delayed diagnosis, Abdominal Trauma Index > 25, Injury Severity Score > 25 and colon injuries were associated to a high complication rate, however, there was no statistically significant difference. There were no mortalities in this group. CONCLUSIONS: A high index of suspicion is required for diagnosis of ureteral injuries. A thorough exploration of all retroperitoneal hematoma after penetrating trauma should be an accurate method of diagnosis; even though it failed in 10% of our cases.

Quantitative Penetration Testing with Item Response Theory

NARCIS (Netherlands)

Arnold, Florian; Pieters, Wolter; Stoelinga, Mariëlle Ida Antoinette

2014-01-01

Existing penetration testing approaches assess the vulnerability of a system by determining whether certain attack paths are possible in practice. Thus, penetration testing has so far been used as a qualitative research method. To enable quantitative approaches to security risk management, including

Quantitative penetration testing with item response theory

NARCIS (Netherlands)

Arnold, Florian; Pieters, Wolter; Stoelinga, Mariëlle

2013-01-01

Existing penetration testing approaches assess the vulnerability of a system by determining whether certain attack paths are possible in practice. Thus, penetration testing has so far been used as a qualitative research method. To enable quantitative approaches to security risk management, including

Chemical Penetration Enhancers for Transdermal Drug Delivery ...

African Journals Online (AJOL)

for transdermal administration. The permeation of drug through skin can be enhanced by both chemical penetration enhancement and physical methods. In this review, we have discussed the chemical penetration enhancement technology for transdermal drug delivery as well as the probable mechanisms of action.

Containment penetration design and analysis by finite element methods

International Nuclear Information System (INIS)

Perry, R.F.; Rigamonti, G.; Dainora, J.

1975-01-01

Containment penetration designs which provide complete support to process piping containing high pressure and high temperature fluids and which do not employ cooling coils, require special provisions to sustain loadings associated with normal/abnormal conditions and to limit maximum temperature transmitted to the containment concrete wall. In order to accomodate piping loads and fluid temperatures within code and regulatory limitations, the containment penetration designs require careful analysis of two critical regions: 1) the portion of the penetration sleeve which is exposed to containment ambient conditions and 2) the portion of the penetration which connects the sleeve to process piping (flued head). Analytical models using finite element representation of process piping, penetration flued head, and exposed sleeve were employed to investigate the penetration assembly design. By application of flexible multi-step analyses, different penetration configurations were evaluated to determine the effects of key design parameters. Among the parameters studied were flued head angles with the process piping, sleeve length and wall thickness. Special designs employing fins welded to the sleeve to further lower the temperature at the concrete wall interface were also investigated and fin geometry effects reported. (Auth.)

Akon - A Penetrator for Europa

Science.gov (United States)

Jones, Geraint

2016-04-01

Jupiter's moon Europa is one of the most intriguing objects in our Solar System. This 2000km-wide body has a geologically young solid water ice crust that is believed to cover a global ocean of liquid water. The presence of this ocean, together with a source of heating through tidal forces, make Europa a conceivable location for extraterrestrial life. The science case for exploring all aspects of this icy world is compelling. NASA has selected the Europa Mission (formerly Europa Clipper) to study Europa in detail in the 2020s through multiple flybys, and ESA's JUICE mission will perform two flybys of the body in the 2030s. The US agency has extended to the European Space Agency an invitation to provide a contribution to their mission. European scientists interested in Europa science and exploration are currently organizing themselves, in the framework of a coordinated Europa M5 Inititative to study concurrently the main options for this ESA contribution, from a simple addition of individual instruments to the NASA spacecraft, to a lander to investigate Europa's surface in situ. A high speed lander - a penetrator - is by far the most promising technology to achieve this latter option within the anticipated mass constraints, and studies of such a hard lander, many funded by ESA, are now at an advanced level. An international team to formally propose an Europa penetrator to ESA in response to the anticipated ESA M5 call is growing. The working title of this proposal is Akon (Άκων), named after the highly accurate javelin gifted to Europa by Zeus in ancient Greek mythology. We present plans for the Akon penetrator, which would impact Europa's surface at several hundred metres per second, and travel up to several metres into the moon's subsurface. To achieve this, the penetrator would be delivered to the surface by a dedicated descent module, to be destroyed on impact following release of the penetrator above the surface. It is planned that the instruments to be

Vehicle effects on human stratum corneum absorption and skin penetration.

Science.gov (United States)

Zhang, Alissa; Jung, Eui-Chang; Zhu, Hanjiang; Zou, Ying; Hui, Xiaoying; Maibach, Howard

2017-05-01

This study evaluated the effects of three vehicles-ethanol (EtOH), isopropyl alcohol (IPA), and isopropyl myristate (IPM)-on stratum corneum (SC) absorption and diffusion of the [ 14 C]-model compounds benzoic acid and butenafine hydrochloride to better understand the transport pathways of chemicals passing through and resident in SC. Following application of topical formulations to human dermatomed skin for 30 min, penetration flux was observed for 24 h post dosing, using an in vitro flow-through skin diffusion system. Skin absorption and penetration was compared to the chemical-SC (intact, delipidized, or SC lipid film) binding levels. A significant vehicle effect was observed for chemical skin penetration and SC absorption. IPA resulted in the greatest levels of intact SC/SC lipid absorption, skin penetration, and total skin absorption/penetration of benzoic acid, followed by IPM and EtOH, respectively. For intact SC absorption and total skin absorption/penetration of butenafine, the vehicle that demonstrated the highest level of sorption/penetration was EtOH, followed by IPA and IPM, respectively. The percent doses of butenafine that were absorbed in SC lipid film and penetrated through skin in 24 h were greatest for IPA, followed by EtOH and IPM, respectively. The vehicle effect was consistent between intact SC absorption and total chemical skin absorption and penetration, as well as SC lipid absorption and chemical penetration through skin, suggesting intercellular transport as a main pathway of skin penetration for model chemicals. These results suggest the potential to predict vehicle effects on skin permeability with simple SC absorption assays. As decontamination was applied 30 min after chemical exposure, significant vehicle effects on chemical SC partitioning and percutaneous penetration also suggest that skin decontamination efficiency is vehicle dependent, and an effective decontamination method should act on chemical solutes in the lipid domain.

Stylet penetration of Cacopsylla pyri; an electrical penetration graph (EPG) study

NARCIS (Netherlands)

Civolani, S.; Leis, M.; Grandi, G.; Garzo, E.; Pasqualini, E.; Musacchi, S.; Chicca, M.; Castaldelli, G.; Rossie, M.; Tjallingii, W.F.

2011-01-01

Detailed information on plant penetration activities by pear psylla Cacopsylla pyri L. (Hemiptera Psyllidae) is essential to study phytoplasma transmission of “Candidatus Phytoplasma pyri” responsible of pear decline disease (PD) and to trace and evaluate resistant traits in new pear tree selections

Prophylactic antibiotics for penetrating abdominal trauma.

Science.gov (United States)

Brand, Martin; Grieve, Andrew

2013-11-18

Penetrating abdominal trauma occurs when the peritoneal cavity is breached. Routine laparotomy for penetrating abdominal injuries began in the 1800s, with antibiotics first being used in World War II to combat septic complications associated with these injuries. This practice was marked with a reduction in sepsis-related mortality and morbidity. Whether prophylactic antibiotics are required in the prevention of infective complications following penetrating abdominal trauma is controversial, however, as no randomised placebo controlled trials have been published to date. There has also been debate about the timing of antibiotic prophylaxis. In 1972 Fullen noted a 7% to 11% post-surgical infection rate with pre-operative antibiotics, a 33% to 57% infection rate with intra-operative antibiotic administration and 30% to 70% infection rate with only post-operative antibiotic administration. Current guidelines state there is sufficient class I evidence to support the use of a single pre-operative broad spectrum antibiotic dose, with aerobic and anaerobic cover, and continuation (up to 24 hours) only in the event of a hollow viscus perforation found at exploratory laparotomy. To assess the benefits and harms of prophylactic antibiotics administered for penetrating abdominal injuries for the reduction of the incidence of septic complications, such as septicaemia, intra-abdominal abscesses and wound infections. Searches were not restricted by date, language or publication status. We searched the following electronic databases: the Cochrane Injuries Group Specialised Register, CENTRAL (The Cochrane Library 2013, issue 12 of 12), MEDLINE (OvidSP), Embase (OvidSP), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED), ISI Web of Science: Conference Proceedings Citation Index- Science (CPCI-S) and PubMed. Searches were last conducted in January 2013. All randomised controlled trials of antibiotic prophylaxis in patients with penetrating abdominal trauma versus no

Deformation analysis of shallow penetration in clay

Science.gov (United States)

Sagaseta, C.; Whittle, A. J.; Santagata, M.

1997-10-01

A new method of analysis is described for estimating the deformations and strains caused by shallow undrained penetration of piles and caissons in clay. The formulation combines previous analyses for steady, deep penetration, with methods used to compute soil deformations due to near-surface ground loss, and is referred to as the Shallow Strain Path Method (SSPM). Complete analytical solutions for the velocity and strain rates are given for a planar wall, an axisymmetric, closed-ended pile and unplugged, open-ended pile geometries. In these examples, the analyses consider a single source penetrating through the soil at a constant rate, generating a family of penetrometers with rounded tips, referred to as simple wall, pile and tube geometries. Soil deformations and strains are obtained by integrating the velocity and strain rates along the particle paths.The transition from shallow to deep penetration is analysed in detail. Shallow penetration causes heave at the ground surface, while settlements occur only in a thin veneer of material adjacent to the shaft and in a bulb-shaped region around the tip. The size of this region increases with the embedment depth. Deformations inside an open-ended pile/caisson are affected significantly by details of the simple tube wall geometry.

Air pollutant penetration through airflow leaks into buildings

Energy Technology Data Exchange (ETDEWEB)

Liu, De-Ling [Univ. of California, Berkeley, CA (United States)

2002-01-01

The penetration of ambient air pollutants into the indoor environment is of concern owing to several factors: (1) epidemiological studies have shown a strong association between ambient fine particulate pollution and elevated risk of human mortality; (2) people spend most of their time in indoor environments; and (3) most information about air pollutant concentration is only available from ambient routine monitoring networks. A good understanding of ambient air pollutant transport from source to receptor requires knowledge about pollutant penetration across building envelopes. Therefore, it is essential to gain insight into particle penetration in infiltrating air and the factors that affect it in order to assess human exposure more accurately, and to further prevent adverse human health effects from ambient particulate pollution. In this dissertation, the understanding of air pollutant infiltration across leaks in the building envelope was advanced by performing modeling predictions as well as experimental investigations. The modeling analyses quantified the extent of airborne particle and reactive gas (e.g., ozone) penetration through building cracks and wall cavities using engineering analysis that incorporates existing information on building leakage characteristics, knowledge of pollutant transport processes, as well as pollutant-surface interactions. Particle penetration is primarily governed by particle diameter and by the smallest dimension of the building cracks. Particles of 0.1-1 μm are predicted to have the highest penetration efficiency, nearly unity for crack heights of 0.25 mm or higher, assuming a pressure differential of 4 Pa or greater and a flow path length of 3 cm or less. Supermicron and ultrafine particles (less than 0.1 μm) are readily deposited on crack surfaces by means of gravitational settling and Brownian diffusion, respectively. The fraction of ozone penetration through building leaks could vary widely, depending significantly on its

Current Understanding of Physicochemical Mechanisms for Cell Membrane Penetration of Arginine-rich Cell Penetrating Peptides: Role of Glycosaminoglycan Interactions.

Science.gov (United States)

Takechi-Haraya, Yuki; Saito, Hiroyuki

2018-01-01

Arginine-rich cell penetrating peptides (CPPs) are very promising drug carriers to deliver membrane-impermeable pharmaceuticals, such as siRNA, bioactive peptides and proteins. CPPs directly penetrate into cells across cell membranes via a spontaneous energy-independent process, in which CPPs appear to interact with acidic lipids in the outer leaflet of the cell membrane. However, acidic lipids represent only 10 to 20% of the total membrane lipid content and in mammalian cell membranes they are predominantly located in the inner leaflet. Alternatively, CPPs favorably bind in a charge density- dependent manner to negatively charged, sulfated glycosaminoglycans (GAGs), such as heparan sulfate and chondroitin sulfate, which are abundant on the cell surface and are involved in many biological functions. We have recently demonstrated that the interaction of CPPs with sulfated GAGs plays a critical role in their direct cell membrane penetration: the favorable enthalpy contribution drives the high-affinity binding of arginine-rich CPPs to sulfated GAGs, initiating an efficient cell membrane penetration. The favorable enthalpy gain is presumably mainly derived from a unique property of the guanidino group of arginine residues forming multidentate hydrogen bonding with sulfate and carboxylate groups in GAGs. Such interactions can be accompanied with charge neutralization of arginine-rich CPPs, promoting their partition into cell membranes. This review summarizes the current understanding of the physicochemical mechanism for lipid membrane penetration of CPPs, and discusses the role of the GAG interactions on the cell membrane penetration of CPPs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

The large-scale integration of wind generation: Impacts on price, reliability and dispatchable conventional suppliers

International Nuclear Information System (INIS)

MacCormack, John; Hollis, Aidan; Zareipour, Hamidreza; Rosehart, William

2010-01-01

This work examines the effects of large-scale integration of wind powered electricity generation in a deregulated energy-only market on loads (in terms of electricity prices and supply reliability) and dispatchable conventional power suppliers. Hourly models of wind generation time series, load and resultant residual demand are created. From these a non-chronological residual demand duration curve is developed that is combined with a probabilistic model of dispatchable conventional generator availability, a model of an energy-only market with a price cap, and a model of generator costs and dispatch behavior. A number of simulations are performed to evaluate the effect on electricity prices, overall reliability of supply, the ability of a dominant supplier acting strategically to profitably withhold supplies, and the fixed cost recovery of dispatchable conventional power suppliers at different levels of wind generation penetration. Medium and long term responses of the market and/or regulator in the long term are discussed.

Application of Uintah-MPM to shaped charge jet penetration of aluminum

International Nuclear Information System (INIS)

Burghardt, J; Leavy, B; Brannon, R; Guilkey, J; Xue, Z

2010-01-01

The capability of the generalized interpolation material point (GIMP) method in simulation of penetration events is investigated. A series of experiments was performed wherein a shaped charge jet penetrates into a stack of aluminum plates. Electronic switches were used to measure the penetration time history. Flash x-ray techniques were used to measure the density, length, radius and velocity of the shaped charge jet. Simulations of the penetration event were performed using the Uintah MPM/GIMP code with several different models of the shaped charge jet being used. The predicted penetration time history for each jet model is compared with the experimentally observed penetration history. It was found that the characteristics of the predicted penetration were dependent on the way that the jet data are translated to a discrete description. The discrete jet descriptions were modified such that the predicted penetration histories fell very close to the range of the experimental data. In comparing the various discrete jet descriptions it was found that the cumulative kinetic energy flux curve represents an important way of characterizing the penetration characteristics of the jet. The GIMP method was found to be well suited for simulation of high rate penetration events.

Medicaid HMO penetration and its mix: did increased penetration affect physician participation in urban markets?

Science.gov (United States)

Adams, E Kathleen; Herring, Bradley

2008-02-01

To use changes in Medicaid health maintenance organization (HMO) penetration across markets over time to test for effects on the extent of Medicaid participation among physicians and to test for differences in the effects of increased use of commercial versus Medicaid-dominant plans within the market. The nationally representative Community Tracking Study's Physician Survey for three periods (1996-1997, 1998-1999, and 2000-2001) on 29,866 physicians combined with Centers for Medicare and Medicaid Services (CMS) and InterStudy data. Market-level estimates of Medicaid HMO penetration are used to test for (1) any participation in Medicaid and (2) the degree to which physicians have an "open" (i.e., nonlimited) practice accepting new Medicaid patients. Models account for physician, firm, and local characteristics, Medicaid relative payment levels adjusted for geographic variation in practice costs, and market-level fixed effects. There is a positive effect of increases in commercial Medicaid HMO penetration on the odds of accepting new Medicaid patients among all physicians, and in particular, among office-based physicians. In contrast, there is no effect, positive or negative, from expanding the penetration of Medicaid-dominant HMO plans within the market. Increases in cost-adjusted Medicaid fees, relative to Medicare levels, were associated with increases in the odds of participation and of physicians having an "open" Medicaid practice. Provider characteristics that consistently lower participation among all physicians include being older, board certified, a U.S. graduate and a solo practitioner. The effects of Medicaid HMO penetration on physician participation vary by the type of plan. If states are able to attract and retain commercial plans, participation by office-based physicians is likely to increase in a way that opens existing practices to more new Medicaid patients. Other policy variables that affect participation include the presence of a federally

Graft rejection episodes after Descemet stripping with endothelial keratoplasty: part two: the statistical analysis of probability and risk factors.

Science.gov (United States)

Price, M O; Jordan, C S; Moore, G; Price, F W

2009-03-01

To investigate risk factors and probability of initial immunological graft rejection episodes after Descemet stripping with endothelial keratoplasty (DSEK). Outcomes of 598 DSEK cases from a single tertiary referral centre were reviewed. Risk factors and probability of rejection were assessed by multivariate Cox proportional hazards modelling. Rejection episodes occurred in 54 eyes of 48 patients. Estimated probability of a rejection episode was 7.6% by 1 year and 12% by 2 years after grafting. Relative risk of rejection was five times higher for African-American patients compared with Caucasians (p = 0.0002). Eyes with pre-existing glaucoma (9%) or steroid-responsive ocular hypertension (27%) had twice the relative risk of rejection (p = 0.045) compared with eyes that did not have those problems. Patient age, sex and corneal diagnosis did not significantly influence rejection risk. Risk of rejection was not increased when fellow eyes were grafted within 1 year of the first eye (p = 0.62). Pre-existing glaucoma or steroid-responsive ocular hypertension and race were the two factors that independently influenced relative risk of rejection after DSEK. Rejection risk was not increased if the fellow eye was grafted within the prior year with DSEK.

Experimental study on the healing process following laser welding of the cornea.

Science.gov (United States)

Rossi, Francesca; Pini, Roberto; Menabuoni, Luca; Mencucci, Rita; Menchini, Ugo; Ambrosini, Stefano; Vannelli, Gabriella

2005-01-01

An experimental study evaluating the application of laser welding of the cornea and the subsequent healing process is presented. The welding of corneal wounds is achieved after staining the cut walls with a solution of the chromophore indocyanine green, and irradiating them with a diode laser (810 nm) operating at low power (60 to 90 mW). The result is a localized heating of the cut, inducing controlled welding of the stromal collagen. In order to optimize this technique and to study the healing process, experimental tests, simulating cataract surgery and penetrating keratoplasty, were performed on rabbits: conventional and laser-induced suturing of corneal wounds were thus compared. A follow-up study 7 to 90 days after surgery was carried out by means of objective and histological examinations, in order to optimize the welding technique and to investigate the subsequent healing process. The analyses of the laser-welded corneas evidenced a faster and more effective restoration of the architecture of the stroma. No thermal damage of the welded stroma was detected, nor were there foreign body reactions or other inflammatory processes. Copyright 2005 Society of Photo-Optical Instrumentation Engineers.

Investigating hydrocarbon contamination using ground penetrating radar

International Nuclear Information System (INIS)

Roest, P.B. van der; Brasser, D.J.S.; Wagebaert, A.P.J.; Stam, P.H.

1996-01-01

The increasing costs of remediating contaminated sites has stimulated research for cost reducing techniques in soil investigation and clean-up techniques. Under the traditional approach soil borings and groundwater wells are used to investigate contaminated soil. These are useful tools to determine the amount and characteristics of the contamination, but they are inefficient and costly in providing information on the location and extent of contamination as they only give information on one point. This often leads to uncertainty in estimating clean-up costs or, even worse, to unsuccessful clean-ups. MAP Environmental Research has developed a technology using Ground Penetrating Radar (GPR) in combination with in-house developed software to locate and define the extent of hydrocarbon contamination. With this technology, the quality of site investigation is increased while costs are reduced. Since 1994 MAP has been improving its technology and has applied it to over 100 projects, which all have been checked afterwards by conventional drilling. This paper gives some general characteristics of the method and presents a case study. The emphasis of this paper lies on the practical application of GPR to hydrocarbon contamination detection

Necrotizing nocardial scleritis after combined penetrating keratoplasty and phacoemulsification with intraocular lens implantation: a case report and review of the literature Esclerite necrosante por Nocardia após ceratoplastia penetrante e facoemulsificação com implante de lente intra-ocular: caso clínico e revisão de literatura

Directory of Open Access Journals (Sweden)

Jerome Charles Ramos-Esteban

2007-03-01

Full Text Available We report the history and clinical presentation of an 88-year-old female with Fuchs dystrophy who developed an acute anterior necrotizing scleritis in her left eye 23 months after an uncomplicated combined penetrating keratoplasty and phacoemulsification with intraocular lens implantation which progressed to slceral perforation with uveal prolapses. The patient underwent a complete systemic work-up for both autoimmune and infectious causes of scleritis. Surgical specimens of the area of scleral perforation were sent for histology and microbiologic studies. Analysis of surgical specimens revealed the presence of culture-proven Nocardia asteroides as a causative agent for the patient's scleral perforation. Results of her systemic autoimmune work-up were not conclusive. Successful treatment with tectonic scleral reinforcement with donor corneal tissue and preserved pericardium, oral and topical trimethoprim-sulfamethoxazole and topical amikacin salvaged the globe and increased vision. The patient's final best-corrected visual acuity sixteen months after her last operation remains 20/70. Prompt surgical intervention with submission of appropriate specimens for pathological diagnosis and microbiology, along with consultation with rheumatologic and infectious disease specialists, are mandatory to minimize visual loss in cases of suspected infectious necrotizing scleritis.Relato de caso de esclerite necrosante aguda, evoluindo para perfuração escleral com prolapso uveal, 23 meses após procedimento de ceratoplastia penetrante e facoemulsificação com implante de lente intra-ocular no olho esquerdo sem intercorrências.A paciente foi submetida à avaliação completa auto-imune para esclerite. Biópsia da área de perfuração escleral foi encaminhada para avaliação patológica e microbiológica. Análise de material cirúrgico revelou presença de cultura proveniente de Nocardia asteroides como agente causal da perfuração escleral. Resultados de

Prevention of serious impurity penetration into water-steam circuits

International Nuclear Information System (INIS)

Burgmann, F.; Bursik, A.; Flunkert, F.; Nieder, R.

1977-01-01

In consequence of reports from several power Plants concerning heavy damages due to penetrations of impurities into the water-steam circuit, the VGB Sub-Committee 'Water Chemistry in Thermal Power Plants' has established a working group to check-up how serious impurity penetration can be avoided. The lecture describes possible danger points. Suitable technical arrangements for the avoidance of penetrations, and possibilities for monitoring will be discussed. Penetration of impurities cannot be avoided with absolute reliability, even when the recommended arrangements and usual monitoring are realized. Additional measures for the protection of water steam circuits will be suggested. (orig.) [de

Consistent constitutive modeling of metallic target penetration using empirical, analytical, and numerical penetration models

Directory of Open Access Journals (Sweden)

John (Jack P. Riegel III

2016-04-01

Full Text Available Historically, there has been little correlation between the material properties used in (1 empirical formulae, (2 analytical formulations, and (3 numerical models. The various regressions and models may each provide excellent agreement for the depth of penetration into semi-infinite targets. But the input parameters for the empirically based procedures may have little in common with either the analytical model or the numerical model. This paper builds on previous work by Riegel and Anderson (2014 to show how the Effective Flow Stress (EFS strength model, based on empirical data, can be used as the average flow stress in the analytical Walker–Anderson Penetration model (WAPEN (Anderson and Walker, 1991 and how the same value may be utilized as an effective von Mises yield strength in numerical hydrocode simulations to predict the depth of penetration for eroding projectiles at impact velocities in the mechanical response regime of the materials. The method has the benefit of allowing the three techniques (empirical, analytical, and numerical to work in tandem. The empirical method can be used for many shot line calculations, but more advanced analytical or numerical models can be employed when necessary to address specific geometries such as edge effects or layering that are not treated by the simpler methods. Developing complete constitutive relationships for a material can be costly. If the only concern is depth of penetration, such a level of detail may not be required. The effective flow stress can be determined from a small set of depth of penetration experiments in many cases, especially for long penetrators such as the L/D = 10 ones considered here, making it a very practical approach. In the process of performing this effort, the authors considered numerical simulations by other researchers based on the same set of experimental data that the authors used for their empirical and analytical assessment. The goals were to establish a

Penetration analysis of projectile with inclined concrete target

Directory of Open Access Journals (Sweden)

Kim S.B.

2015-01-01

Full Text Available This paper presents numerical analysis result of projectile penetration with concrete target. We applied dynamic material properties of 4340 steels, aluminium and explosive for projectile body. Dynamic material properties were measured with static tensile testing machine and Hopkinson pressure bar tests. Moreover, we used three concrete damage models included in LS-DYNA 3D, such as SOIL_CONCRETE, CSCM (cap model with smooth interaction and CONCRETE_DAMAGE (K&C concrete models. Strain rate effect for concrete material is important to predict the fracture deformation and shape of concrete, and penetration depth for projectiles. CONCRETE_DAMAGE model with strain rate effect also applied to penetration analysis. Analysis result with CSCM model shows good agreement with penetration experimental data. The projectile trace and fracture shapes of concrete target were compared with experimental data.

Penetration analysis of projectile with inclined concrete target

Science.gov (United States)

Kim, S. B.; Kim, H. W.; Yoo, Y. H.

2015-09-01

This paper presents numerical analysis result of projectile penetration with concrete target. We applied dynamic material properties of 4340 steels, aluminium and explosive for projectile body. Dynamic material properties were measured with static tensile testing machine and Hopkinson pressure bar tests. Moreover, we used three concrete damage models included in LS-DYNA 3D, such as SOIL_CONCRETE, CSCM (cap model with smooth interaction) and CONCRETE_DAMAGE (K&C concrete) models. Strain rate effect for concrete material is important to predict the fracture deformation and shape of concrete, and penetration depth for projectiles. CONCRETE_DAMAGE model with strain rate effect also applied to penetration analysis. Analysis result with CSCM model shows good agreement with penetration experimental data. The projectile trace and fracture shapes of concrete target were compared with experimental data.

Age-related percutaneous penetration part 1: skin factors.

Science.gov (United States)

Konda, S; Meier-Davis, S R; Cayme, B; Shudo, J; Maibach, H I

2012-05-01

Changes in the skin that occur in the elderly may put them at increased risk for altered percutaneous penetration from pharmacotherapy along with potential adverse effects. Skin factors that may have a role in age-related percutaneous penetration include blood flow, pH, skin thickness, hair and pore density, and the content and structure of proteins, glycosaminoglycans (GAGs), water, and lipids. Each factor is examined as a function of increasing age along with its potential impact on percutaneous penetration. Additionally, topical drugs that successfully overcome the barrier function of the skin can still fall victim to cutaneous metabolism, thereby producing metabolites that may have increased or decreased activity. This overview discusses the current data and highlights the importance of further studies to evaluate the impact of skin factors in age-related percutaneous penetration.

Customized photorefractive keratectomy to correct high ametropia after penetrating keratoplasty: A pilot study

Directory of Open Access Journals (Sweden)

Giuseppe De Rosa

2015-07-01

Conclusion: Our pilot study suggests that customized PRK can be a safe and effective method for treating ametropia and irregular astigmatisms after PK. Future studies with larger samples and longer follow-ups should be performed to confirm these results.

Multi-Feature Based Multiple Landmine Detection Using Ground Penetration Radar

Directory of Open Access Journals (Sweden)

S. Park

2014-06-01

Full Text Available This paper presents a novel method for detection of multiple landmines using a ground penetrating radar (GPR. Conventional algorithms mainly focus on detection of a single landmine, which cannot linearly extend to the multiple landmine case. The proposed algorithm is composed of four steps; estimation of the number of multiple objects buried in the ground, isolation of each object, feature extraction and detection of landmines. The number of objects in the GPR signal is estimated by using the energy projection method. Then signals for the objects are extracted by using the symmetry filtering method. Each signal is then processed for features, which are given as input to the support vector machine (SVM for landmine detection. Three landmines buried in various ground conditions are considered for the test of the proposed method. They demonstrate that the proposed method can successfully detect multiple landmines.

Numerical analysis of impact-penetration problems for nuclear reactor safety

International Nuclear Information System (INIS)

Dubois, J.J.; Chedmail, J.F.; Bianchini, J.C.

1977-01-01

This paper discusses the finite element and finite difference analysis of two impact penetration problems, namely a fuel cask drop on a foundation slab and a missile penetration into a reinforced concrete structure. For a realistic detailed analysis, advanced techniques were required in the following areas: reinforced concrete simulation; remeshing algorithms for penetration induced distortions; boundary condition. The fuel cask drop on a concrete slab generates complex elasto plastic waves which propagate towards the pool where tensile cracks might appear. The problem is analysed in two steps: calculation of the energy absorbed locally around the impacted area; calculation of the three dimensional wave propagation towards the pool. For the analysis of missile penetration problems, two examples are shown: a 3000 kg missile with a velocity of 132 m/s penetrates a 1.2 m thick concrete wall (PAM-GDYNS) and a 3600 kg missile with a velocity of 90 m/s (F.D. Program HEMP-ESI) penetrates a wall at a floor level. For the second case, the computed impact-penetration mechanism is

Water Penetration through a Superhydrophobic Mesh During a Drop Impact

Science.gov (United States)

Ryu, Seunggeol; Sen, Prosenjit; Nam, Youngsuk; Lee, Choongyeop

2017-01-01

When a water drop impacts a mesh having submillimeter pores, a part of the drop penetrates through the mesh if the impact velocity is sufficiently large. Here we show that different surface wettability, i.e., hydrophobicity and superhydrophobicity, leads to different water penetration dynamics on a mesh during drop impact. We show, despite the water repellence of a superhydrophobic surface, that water can penetrate a superhydrophobic mesh more easily (i.e., at a lower impact velocity) over a hydrophobic mesh via a penetration mechanism unique to a superhydrophobic mesh. On a superhydrophobic mesh, the water penetration can occur during the drop recoil stage, which appears at a lower impact velocity than the critical impact velocity for water penetration right upon impact. We propose that this unique water penetration on a superhydrophobic mesh can be attributed to the combination of the hydrodynamic focusing and the momentum transfer from the water drop when it is about to bounce off the surface, at which point the water drop retrieves most of its kinetic energy due to the negligible friction on superhydrophobic surfaces.

Topological properties of the limited penetrable horizontal visibility graph family

Science.gov (United States)

Wang, Minggang; Vilela, André L. M.; Du, Ruijin; Zhao, Longfeng; Dong, Gaogao; Tian, Lixin; Stanley, H. Eugene

2018-05-01

The limited penetrable horizontal visibility graph algorithm was recently introduced to map time series in complex networks. In this work, we extend this algorithm to create a directed-limited penetrable horizontal visibility graph and an image-limited penetrable horizontal visibility graph. We define two algorithms and provide theoretical results on the topological properties of these graphs associated with different types of real-value series. We perform several numerical simulations to check the accuracy of our theoretical results. Finally, we present an application of the directed-limited penetrable horizontal visibility graph to measure real-value time series irreversibility and an application of the image-limited penetrable horizontal visibility graph that discriminates noise from chaos. We also propose a method to measure the systematic risk using the image-limited penetrable horizontal visibility graph, and the empirical results show the effectiveness of our proposed algorithms.

Uneventful Anterior Migration of Intravitreal Ozurdex Implant in a Patient with Iris-Sutured Intraocular Lens and Descemet Stripping Automated Endothelial Keratoplasty

Directory of Open Access Journals (Sweden)

Andleeb Zafar

2018-02-01

Full Text Available Purpose: We report here the case of a patient with anterior segment migration of intravitreal dexamethasone implant as well as its management and outcome. Methods: The patient had the following sequence of events: complicated cataract surgery, iris-sutured intraocular lens implant, followed by cystoid macular edema treated with intravitreal Avastin, retinal vein occlusion treated with intravitreal dexamethasone implant, corneal decompensation treated with Descemet stripping automated endothelial keratoplasty (DSAEK, and finally recurrence of macular edema treated with repeated intravitreal dexamethasone implant. Results: Dexamethasone implant had completely dissolved from the eye 12 weeks after insertion without any complication. Conclusion: A conservative approach with regular monitoring in the situation of a quiet anterior segment without any corneal decompensation can provide enough time for the implant to dissolve without causing any complication to the involved eye, avoiding any additional surgical intervention, as presented in this case report. Despite the fact that the implant was left for natural dissolution, there were no adverse effects related to the graft or the eye.

Impacts of fleet types and charging modes for electric vehicles on emissions under different penetrations of wind power

Science.gov (United States)

Chen, Xinyu; Zhang, Hongcai; Xu, Zhiwei; Nielsen, Chris P.; McElroy, Michael B.; Lv, Jiajun

2018-05-01

Current Chinese policy promotes the development of both electricity-propelled vehicles and carbon-free sources of power. Concern has been expressed that electric vehicles on average may emit more CO2 and conventional pollutants in China. Here, we explore the environmental implications of investments in different types of electric vehicle (public buses, taxis and private light-duty vehicles) and different modes (fast or slow) for charging under a range of different wind penetration levels. To do this, we take Beijing in 2020 as a case study and employ hourly simulation of vehicle charging behaviour and power system operation. Assuming the slow-charging option, we find that investments in electric private light-duty vehicles can result in an effective reduction in the emission of CO2 at several levels of wind penetration. The fast-charging option, however, is counter-productive. Electrifying buses and taxis offers the most effective option to reduce emissions of NOx, a major precursor for air pollution.

Skin pre-ablation and laser assisted microjet injection for deep tissue penetration.

Science.gov (United States)

Jang, Hun-Jae; Yeo, Seonggu; Yoh, Jack J

2017-04-01

For conventional needless injection, there still remain many unresolved issues such as the potential for cross-contamination, poor reliability of targeted delivery dose, and significantly painstaking procedures. As an alternative, the use of microjets generated with Er:YAG laser for delivering small doses with controlled penetration depths has been reported. In this study, a new system with two stages is evaluated for effective transdermal drug delivery. First, the skin is pre-ablated to eliminate the hard outer layer and second, laser-driven microjet penetrates the relatively weaker and freshly exposed epidermis. Each stage of operation shares a single Er:YAG laser that is suitable for skin ablation as well as for the generation of a microjet. In this study, pig skin is selected for quantification of the injection depth based on the two-stage procedure, namely pre-ablation and microjet injection. The three types of pre-ablation devised here consists of bulk ablation, fractional ablation, and fractional-rotational ablation. The number of laser pulses are 12, 18, and 24 for each ablation type. For fractional-rotational ablation, the fractional beams are rotated by 11.25° at each pulse. The drug permeation in the skin is evaluated using tissue marking dyes. The depth of penetration is quantified by a cross sectional view of the single spot injections. Multi-spot injections are also carried out to control the dose and spread of the drug. The benefits of a pre-ablation procedure prior to the actual microjet injection to the penetration is verified. The four possible combinations of injection are (a) microjet only; (b) bulk ablation and microjet injection; (c) fractional ablation and microjet injection; and (d) fractional-rotational ablation and microjet injection. Accordingly, the total depth increases with injection time for all cases. In particular, the total depth of penetration attained via fractional pre-ablation increased by 8 ∼ 11% and that of fractional

Containment penetration design and analysis by finite element methods

International Nuclear Information System (INIS)

Perry, R.F.; Rigamonti, G.; Dainora, J.

1975-01-01

Containment penetration designs which provide complete support to process piping containing high pressure and high temperature fluids and which do not employ cooling coils, require special provisions to sustain loadings associated with normal/abnormal conditions and to limit maximum temperature transmitted to the containment concrete wall. In order to accommodate piping imposed loads and fluid temperatures within code and regulatory limitations, the containment penetration designs require careful analysis of two critical regions: the portion of the penetration sleeve which is exposed to containment ambient conditions and the portion of the penetration which connects the sleeve to process piping (flued head). The length and thickness of the sleeve must be designed to provide maximum heat dissipation to the atmosphere and minimum heat conduction through the sleeve to meet concrete temperature limitations. The sleeve must have the capability to transmit the postulated piping loads to concrete embedments in the containment shell. The penetration flued head design must be strong enough to transfer high mechanical loads and be flexible enough to accommodate the thermal stresses generated by the high temperature fluid. Analytical models using finite element representations of process piping, penetration flued head, and exposed sleeve were employed to investigate the penetration assembly design. By application of flexible multi-step analyses, different penetration configurations were evaluated to determine the effects of key design parameters. Among the parameters studied were flued head profiles, flued head angles with the process piping, sleeve length and wall thickness. Special designs employing fins welded to the sleeve to lower the temperature at the concrete wall interface were investigated and fin geometry effects reported

Network Penetration Testing and Research

Science.gov (United States)

Murphy, Brandon F.

2013-01-01

This paper will focus the on research and testing done on penetrating a network for security purposes. This research will provide the IT security office new methods of attacks across and against a company's network as well as introduce them to new platforms and software that can be used to better assist with protecting against such attacks. Throughout this paper testing and research has been done on two different Linux based operating systems, for attacking and compromising a Windows based host computer. Backtrack 5 and BlackBuntu (Linux based penetration testing operating systems) are two different "attacker'' computers that will attempt to plant viruses and or NASA USRP - Internship Final Report exploits on a host Windows 7 operating system, as well as try to retrieve information from the host. On each Linux OS (Backtrack 5 and BlackBuntu) there is penetration testing software which provides the necessary tools to create exploits that can compromise a windows system as well as other operating systems. This paper will focus on two main methods of deploying exploits 1 onto a host computer in order to retrieve information from a compromised system. One method of deployment for an exploit that was tested is known as a "social engineering" exploit. This type of method requires interaction from unsuspecting user. With this user interaction, a deployed exploit may allow a malicious user to gain access to the unsuspecting user's computer as well as the network that such computer is connected to. Due to more advance security setting and antivirus protection and detection, this method is easily identified and defended against. The second method of exploit deployment is the method mainly focused upon within this paper. This method required extensive research on the best way to compromise a security enabled protected network. Once a network has been compromised, then any and all devices connected to such network has the potential to be compromised as well. With a compromised

Penetrating Brain Injury after Suicide Attempt with Speargun

Directory of Open Access Journals (Sweden)

John Ross Williams

2014-07-01

Full Text Available Penetrating cranial injury by mechanisms other than are exceedingly rare, and so strategies and guidelines for the management of PBI are largely informed by data from higher-velocity penetrating injuries. Here we present a case of penetrating brain injury by the low velocity mechanism of a harpoon from an underwater fishing speargun in an attempted suicide by a 56-year-old Caucasian male. The case raised a number of interesting points in management of lower-velocity penetrating brain injury (LVPBI, including benefit in delaying foreign body removal to allow for tamponade; the importance of history taking in establishing the social/legal significance of the events surrounding the injury; the use of cerebral angiogram in all cases of PBI; advantages of using DECT to reduce artifact when available; and antibiotic prophylaxis in the context of idiosyncratic histories of usage of penetrating objects before coming in contact with the intracranial environment. We present here the management of the case in full along with an extended discussion and review of existing literature regarding key points in management of LVPBI vs. higher velocity forms of intracranial injury.

Complications and management in Descemet′s stripping endothelial keratoplasty: Analysis of consecutive 430 cases

Directory of Open Access Journals (Sweden)

Samar K Basak

2014-01-01

Full Text Available Purpose: To analyze the complications and their managements in Descemet′s stripping endothelial keratoplasty (DSEK in consecutive 430 cases by single surgeon in a tertiary eye hospital. Materials and Methods: 430 eyes of 366 patients with endothelial dysfunctions scheduled for DSEK, were analyzed retrospectively. In all cases donor dissection was performed manually, and ′Taco′ insertion and unfolding technique was used. Intra-operative and postoperative complications with their managements and outcomes were reviewed retrospectively. Periodic endothelial cell density was analyzed for each patient till the last visit. Follow-up period was between 3 to 60 months (mean 18.7 months. Results: 13 (3.0% eyes had operative complications during donor dissection and 16 (3.7% had during recipient procedure. In 7 (1.6% eyes, donor lenticule was replaced with a new one during the surgery. In early postoperative period, 21 (4.9% eyes had donor dislocation and 12 (2.8% eyes had air-induced pupillary block; and they were managed immediately. 2 cases had primary graft failure and in 1 case had postoperative bacterial endophthalmitis requiring evisceration. In late postoperative period, 48 (11.3% eyes had secondary glaucoma and 14 (3.3% eyes had late secondary graft failure. Endothelial rejection occurred in 5 (1.2% cases. Mean endothelial cell loss was 19.7% after 3 months and 54.2% after 5 years. Total graft failure in this series was 31 (7.2% and in 17 cases re-DSEK was performed successfully. Conclusions: Both operative and postoperative complications do occur in DSEK. Most of these complications can be managed by medical or appropriate surgical means. Some of the complications can be avoided and reduced with experience.

CNS penetration of ART in HIV-infected children

NARCIS (Netherlands)

van den Hof, Malon; Blokhuis, Charlotte; Cohen, Sophie; Scherpbier, Henriette J.; Wit, Ferdinand W. N. M.; Pistorius, M. C. M.; Kootstra, Neeltje A.; Teunissen, Charlotte E.; Mathot, Ron A. A.; Pajkrt, Dasja

2018-01-01

Background: Paediatric data on CNS penetration of antiretroviral drugs are scarce. Objectives: To evaluate CNS penetration of antiretroviral drugs in HIV-infected children and explore associations with neurocognitive function. Patients and methods: Antiretroviral drug levels were measured in paired

Effects of soap-water wash on human epidermal penetration.

Science.gov (United States)

Zhu, Hanjiang; Jung, Eui-Chang; Phuong, Christina; Hui, Xiaoying; Maibach, Howard

2016-08-01

Skin decontamination is a primary interventional method used to decrease dermal absorption of hazardous contaminants, including chemical warfare agents, pesticides and industrial pollutants. Soap and water wash, the most common and readily available decontamination system, may enhance percutaneous absorption through the "wash-in effect." To understand better the effect of soap-water wash on percutaneous penetration, and provide insight to improving skin decontamination methods, in vitro human epidermal penetration rates of four C(14) -labeled model chemicals (hydroquinone, clonidine, benzoic acid and paraoxon) were assayed using flow-through diffusion cells. Stratum corneum (SC) absorption rates of these chemicals at various hydration levels (0-295% of the dry SC weights) were determined and compared with the results of the epidermal penetration study to clarify the effect of SC hydration on skin permeability. Results showed accelerated penetration curves of benzoic acid and paraoxon after surface wash at 30 min postdosing. Thirty minutes after washing (60 min postdosing), penetration rates of hydroquinone and benzoic acid decreased due to reduced amounts of chemical on the skin surface and in the SC. At the end of the experiment (90 min postdosing), a soap-water wash resulted in lower hydroquinone penetration, greater paraoxon penetration and similar levels of benzoic acid and clonidine penetration compared to penetration levels in the non-wash groups. The observed wash-in effect agrees with the enhancement effect of SC hydration on the SC chemical absorption rate. These results suggest SC hydration derived from surface wash to be one cause of the wash-in effect. Further, the occurrence of a wash-in effect is dependent on chemical identity and elapsed time between exposure and onset of decontamination. By reducing chemical residue quantity on skin surface and in the SC reservoir, the soap-water wash may decrease the total quantity of chemical absorbed in the

Corneal Transplantation in Auckland, New Zealand, 1999-2009: Indications, Patient Characteristics, Ethnicity, Social Deprivation, and Access to Services.

Science.gov (United States)

Crawford, Alexandra Z; McKelvie, James; Craig, Jennifer P; McGhee, Charles N J; Patel, Dipika V

2017-05-01

To analyze characteristics and indications for corneal transplantation in patients undergoing penetrating, lamellar, and endothelial keratoplasty in Auckland, New Zealand (NZ). Corneal transplantation data from the NZ National Eye Bank and hospital records of corneal transplant recipients in the Auckland region from January 1, 2000, to December 31, 2009, were collated. Patient demographics, preoperative diagnosis, indication, ocular and medical history, visual acuity, deprivation index, and access to transplantation surgery were analyzed. A total of 941 corneal transplants involving 770 patients were included for analysis. Mean age was 46 years. Age and ethnicity varied according to the transplant indication. A male preponderance and disproportionally high rates of Māori and Pacific ethnicity with a mean age of 30 years were observed in transplants for keratoconus. A total of 67.2% of corneal transplants were completed in the public health system and were associated with higher levels of deprivation than those completed in private facilities. Preoperative visual acuity varied according to the transplant type and indication. The most common clinical indication for corneal transplantation was keratoconus (41.3%), followed by repeat transplantation (21.0%). There was no significant change in the relative proportion of transplant indications in any year over the duration of this study (P = 0.41). A contralateral corneal transplant was present in 24.4% and glaucoma in 12.8% of penetrating keratoplasty recipients. Keratoconus is the leading indication for corneal transplantation in Auckland, NZ, and involves a disproportionately high rate of Māori and Pacific transplant recipients with a male preponderance and comparatively low mean age at the time of surgery.

Elastic behavior of MFI-type zeolites: Compressibility of H-ZSM-5 in penetrating and non-penetrating media

International Nuclear Information System (INIS)

Quartieri, Simona; Montagna, Gabriele; Arletti, Rossella; Vezzalini, Giovanna

2011-01-01

The elastic behavior of H-ZSM-5 was investigated by in-situ synchrotron X-ray powder diffraction, using both silicone oil (s.o.) and (16:3:1) methanol:ethanol:water (m.e.w.) as 'non-penetrating' and 'penetrating' pressure transmitting media, respectively. From P amb to 6.2 GPa the volume reduction observed in s.o. is 16.6%. This testifies that H-ZSM-5 is one of the most flexible microporous materials up to now compressed in s.o. Volume reduction observed in m.e.w. up to 7.6 GPa is 14.6%. A strong increase in the total electron number of the extraframework system, due to the penetration of water/alcohol molecules in the pores, is observed in m.e.w. This effect is the largest up to now observed in zeolites undergoing this phenomenon without cell volume expansion. The higher compressibility in s.o. than in m.e.w. can be ascribed to the penetration of the extra-water/alcohol molecules, which stiffen the structure and contrast the channel deformations. - Graphical abstract: High-pressure behavior of H-ZSM-5 compressed in (16:3:1) methanol:ethanol:water: (a) projection of the structure along the [0 1 0] direction at P amb , 2 GPa and after pressure release to original ambient conditions (P amb (rev)), and (b) P-dependence of the extraframework content expressed as total number of electrons (gray square represents the number of the extraframework electrons at P amb after decompression). Highlights: → X-ray powder diffraction study of H-ZSM-5 compressibility. → H-ZSM-5 is one of the softest porous material compressed in silicon oil. → Penetration of additional water/alcohol molecules upon compression in m.e.w. → Extra molecules contribute to stiffen the structure and to contrast HP effects.

Analysis of 178 penetrating stomach and small bowel injuries.

Science.gov (United States)

Salim, Ali; Teixeira, Pedro G R; Inaba, Kenji; Brown, Carlos; Browder, Timothy; Demetriades, Demetrios

2008-03-01

Surgical site infections (SSIs), such as wound infection, fascial dehiscence, and intraabdominal abscess, commonly occur following penetrating abdominal trauma. However, most of the literature involves penetrating colon injuries. There are few reports describing complications following penetrating stomach and small bowel injuries. Based on the hypothesis that SSIs are commonly found following penetrating stomach and small bowel trauma, a prospective observational study was performed at an academic Level I trauma center from March 1, 2004 until August 31, 2006. The subjects were patients who had sustained a penetrating injury to the stomach or small bowel. Patients were followed for the development of an SSI, defined as wound infection, fascial dehiscence, or intraabdominal abscess. A total of 178 patients were admitted with penetrating stomach or small bowel injuries over the 29-month period. There were 121 (68%) gunshot injuries and 57 (32%) stab wounds. Associated intraabdominal injuries occurred in 74% of patients. Overall, SSIs occurred in 20% of cases. Risk factors for SSI included associated duodenal or colon injury, whereas time to operating room, blood loss, and type and duration of antibiotic use were not. When associated colon injuries were excluded, SSIs occurred in 16% of patients with gastric injuries and 13% of those with small bowel injuries. SSIs commonly follow penetrating stomach and small bowel trauma. Risk factors for SSI include associated duodenal or colon injury. Delay to operating room, blood loss, and type and length of antibiotic prophylaxis were not associated with an increased risk of SSI.

Cycling of conventional power plants: Technical limits and actual costs

International Nuclear Information System (INIS)

Van den Bergh, Kenneth; Delarue, Erik

2015-01-01

Highlights: • Literature reports a wide range of cycling parameters (technical and cost-related). • The impact of different cycling parameters is assessed. • The German 2013 system is studied as a case study. • Even for stringent parameters, the dynamic limit of the portfolio is not reached. • Cycling costs can be reduced with 40% when taken into account in the scheduling. - Abstract: Cycling of conventional generation units is an important source of operational flexibility in the electricity generation system. Cycling is changing the power output of conventional units by means of ramping and switching (starting up and shutting down). In the literature, a wide range of technical and cost-related cycling parameters can be found. Different studies allocate different cycling parameters to similar generation units. This paper assesses the impact of different cycling parameters allocated to a conventional generation portfolio. Both the technical limitations of power plants and all costs related to cycling are considered. The results presented in this paper follow from a unit commitment model, used for a case study based on the German 2013 system. The conventional generation portfolio has to deliver different residual load time series, corresponding to different levels of renewables penetration. The study shows, under the assumptions made, that although the dynamic limits of some units are reached, the limits of the conventional generation portfolio as a whole are not reached, even if stringent dynamic parameters are assigned to the generation portfolio and a highly variable residual load is imposed to the system. The study shows also the importance of including full cycling costs in the unit commitment scheduling. The cycling cost can be reduced by up to 40% when fully taken into account

NRC Information Notice No. 93-25: Electrical penetration assembly degradation

International Nuclear Information System (INIS)

Grimes, B.K.

1993-01-01

In July 1987 and in October 1989, the licensee for the Trojan Nuclear Plant, the Portland and General Electric Company, reported problems with containment air leakage through its Bunker-Ramo electrical penetration assembly seals. In July and August 1991, the NRC inspected the use of containment electrical penetration assembly seals at Trojan and concluded that the licensee had not established an effective program for trending and evaluating electrical penetration assembly seal leakage. On October 28, 1991, while the plant was in a refueling outage, the licensee reported to the NRC that in the originally installed electrical penetration assemblies, the seal (polyurethane) and lubricant (Celvacen or Glycerin) materials were inappropriate for the application. The licensee concluded that these materials may cause seal degradation and that the seals may become degraded if subjected to design basis accident conditions for moisture or temperature. The licensee replaced the electrical penetration assembly seal with an environmentally qualified ethylene propylene rubber seal and added a silicone rubber backup O-ring to the outer face of each electrical penetration assembly module. The licensee subsequently replaced all the Bunker-Ramo electrical penetration assemblies with Conax assemblies

Penetration testing with Perl

CERN Document Server

Berdeaux, Douglas

2014-01-01

If you are an expert Perl programmer interested in penetration testing or information security, this guide is designed for you. However, it will also be helpful for you even if you have little or no Linux shell experience.

Compound antimalarial ethosomal cataplasm: preparation, evaluation, and mechanism of penetration enhancement

Directory of Open Access Journals (Sweden)

Shen S

2015-06-01

Full Text Available Shuo Shen, Shu-Zhi Liu, Yu-Shi Zhang, Mao-Bo Du, Ai-Hua Liang, Li-Hua Song, Zu-Guang Ye Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, People’s Republic of China Abstract: Malaria is still a serious public health problem in some parts of the world. The problems of recurrence and drug resistance are increasingly more serious. Thus, it is necessary to develop a novel antimalarial agent. The objectives of this study were to construct a novel compound antimalarial transdermal nanosystem–ethosomal cataplasm, to investigate its characteristics and efficiency, and to systematically explore the penetration-enhancing mechanisms of ethosomal cataplasm. Artesunate-loaded ethosomes and febrifugine-loaded ethosomes were prepared, and their characteristics were evaluated. Drug-loaded ethosomes were incorporated in the matrix of cataplasm to form the compound antimalarial ethosomal cataplasm. With the help of ethosomal technology, the accumulated permeation quantity of artesunate significantly increased at 8 hours after administration, which was 1.57 times as much as that of conventional cataplasm. Soon after administration, the ethosomal cataplasm could make a large quantity of antimalarial drug quickly penetrate through skin, then the remaining drug in the ethosomal cataplasm could be steadily released. These characteristics of ethosomal cataplasm are favorable for antimalarial drugs to kill Plasmodium spp. quickly and prevent the resurgence of Plasmodium spp. As expected, the ethosomal cataplasm showed good antimalarial efficiency in this experiment. The negative conversion rates were 100% and the recurrence rates were 0% at all dosages. The mechanism of penetration enhancement of the ethosomal cataplasm was systematically explored using an optics microscope, polarization microscope, and transmission electron microscopy. The microstructure, ultrastructure, and birefringent structure in skin were observed. Data

Standard practice for liquid penetrant examination for general industry

CERN Document Server

American Society for Testing and Materials. Philadelphia

2009-01-01

1.1 This practice covers procedures for penetrant examination of materials. Penetrant testing is a nondestructive testing method for detecting discontinuities that are open to the surface such as cracks, seams, laps, cold shuts, shrinkage, laminations, through leaks, or lack of fusion and is applicable to in-process, final, and maintenance testing. It can be effectively used in the examination of nonporous, metallic materials, ferrous and nonferrous metals, and of nonmetallic materials such as nonporous glazed or fully densified ceramics, as well as certain nonporous plastics, and glass. 1.2 This practice also provides a reference: 1.2.1 By which a liquid penetrant examination process recommended or required by individual organizations can be reviewed to ascertain its applicability and completeness. 1.2.2 For use in the preparation of process specifications and procedures dealing with the liquid penetrant testing of parts and materials. Agreement by the customer requesting penetrant inspection is strongly rec...

Evaporation and skin penetration characteristics of mosquito repellent formulations

International Nuclear Information System (INIS)

Reifenrath, W.G.; Hawkins, G.S.; Kurtz, M.S.

1989-01-01

Formulations of the mosquito repellent N,N-diethyl-3-methylbenzamide (deet) in combination with a variety of additives were developed to control repellent evaporation and percutaneous penetration. Deet was also formulated with the repellent dimethyl phthalate to study the interaction of the two compounds on the skin. The evaporation and penetration processes were evaluated on whole and split-thickness pig skin using radiolabeled repellents with an in vitro apparatus. Under essentially still air and air flow conditions, one of the deet formulations resulted in significantly reduced total evaporation and percutaneous penetration of deet as compared to unformulated repellent. When deet and dimethyl phthalate were combined, neither repellent affected the total amount of evaporation and penetration of the other compound. However, initial percutaneous penetration and evaporation rates were slightly less and decayed less rapidly than when both chemicals were tested separately at the same dose. These results indicated a degree of competition of the two compounds for the same avenues of loss

Integrated computation model of lithium-ion battery subject to nail penetration

International Nuclear Information System (INIS)

Liu, Binghe; Yin, Sha; Xu, Jun

2016-01-01

Highlights: • A coupling model to predict battery penetration process is established. • Penetration test is designed and validates the computational model. • Governing factors of the penetration induced short-circuit is discussed. • Critical safety battery design guidance is suggested. - Abstract: The nail penetration of lithium-ion batteries (LIBs) has become a standard battery safety evaluation method to mimic the potential penetration of a foreign object into LIB, which can lead to internal short circuit with catastrophic consequences, such as thermal runaway, fire, and explosion. To provide a safe, time-efficient, and cost-effective method for studying the nail penetration problem, an integrated computational method that considers the mechanical, electrochemical, and thermal behaviors of the jellyroll was developed using a coupled 3D mechanical model, a 1D battery model, and a short circuit model. The integrated model, along with the sub-models, was validated to agree reasonably well with experimental test data. In addition, a comprehensive quantitative analysis of governing factors, e.g., shapes, sizes, and displacements of nails, states of charge, and penetration speeds, was conducted. The proposed computational framework for LIB nail penetration was first introduced. This framework can provide an accurate prediction of the time history profile of battery voltage, temperature, and mechanical behavior. The factors that affected the behavior of the jellyroll under nail penetration were discussed systematically. Results provide a solid foundation for future in-depth studies on LIB nail penetration mechanisms and safety design.

Generic penetration in the retail antidepressant market.

Science.gov (United States)

Ventimiglia, Jeffrey; Kalali, Amir H

2010-06-01

In this article, we explore the accelerated penetration of generic antidepressants in the United States market following the availability of generic citalopram and sertraline. Analysis suggests that overall, generic penetration into the antidepressant market has grown from approximately 41 percent in January 2004 to over 73 percent in January 2010. Similar trends are uncovered when branded and generic prescriptions are analyzed by specialty.

Quantitative wood–adhesive penetration with X-ray computed tomography

Energy Technology Data Exchange (ETDEWEB)

Paris, Jesse L.; Kamke, Frederick A. (Oregon State U.); (Willamette Valley)

2015-09-01

Micro X-ray computed tomography (XCT) was used to analyze the 3D adhesive penetration behavior of different wood–adhesive bondlines. Three adhesives, a phenol formaldehyde (PF), a polymeric diphenylmethane diisocyanate (pMDI), and a hybrid polyvinyl acetate (PVA), all tagged with iodine for enhanced X-ray attenuation, were used to prepare single-bondline laminates in two softwoods, Douglas-fir and loblolly pine, and one hardwood, a hybrid polar. Adhesive penetration depth was measured with two separate calculations, and results were compared with 2D fluorescent micrographs. A total of 54 XCT scans were collected, representing six replicates of each treatment type; each replicate, however, consisted of approximately 1500 individual, cross-section slices stacked along the specimen length. As these adhesives were highly modified, the presented results do not indicate typical behavior for their broader adhesive classes. Still, clear penetration differences were observed between each adhesive type, and between wood species bonded with both the PF and pMDI adhesives. Furthermore, penetration results depended on the calculation method used. Two adhesive types with noticeably different resin distributions in the cured bondline, showed relatively similar penetration depths when calculated with a traditional effective penetration equation. However, when the same data was calculated with a weighted penetration calculation, which accounts for both adhesive area and depth, the results appeared to better represent the different distributions depicted in the photomicrographs and tomograms. Additionally, individual replicate comparisons showed variation due to specimen anatomy, not easily observed or interpreted from 2D images. Finally, 3D views of segmented 3D adhesive phases offered unique, in-situ views of the cured adhesive structures. In particular, voids formed by CO₂ bubbles generated during pMDI cure were clearly visible in penetrated columns of the solidified

Evaluation Technique of Chloride Penetration Using Apparent Diffusion Coefficient and Neural Network Algorithm

Directory of Open Access Journals (Sweden)

Yun-Yong Kim

2014-01-01

Full Text Available Diffusion coefficient from chloride migration test is currently used; however this cannot provide a conventional solution like total chloride contents since it depicts only ion migration velocity in electrical field. This paper proposes a simple analysis technique for chloride behavior using apparent diffusion coefficient from neural network algorithm with time-dependent diffusion phenomena. For this work, thirty mix proportions of high performance concrete are prepared and their diffusion coefficients are obtained after long term-NaCl submerged test. Considering time-dependent diffusion coefficient based on Fick’s 2nd Law and NNA (neural network algorithm, analysis technique for chloride penetration is proposed. The applicability of the proposed technique is verified through the results from accelerated test, long term submerged test, and field investigation results.

WAPTT - Web Application Penetration Testing Tool

Directory of Open Access Journals (Sweden)

DURIC, Z.

2014-02-01

Full Text Available Web applications vulnerabilities allow attackers to perform malicious actions that range from gaining unauthorized account access to obtaining sensitive data. The number of reported web application vulnerabilities in last decade is increasing dramatically. The most of vulnerabilities result from improper input validation and sanitization. The most important of these vulnerabilities based on improper input validation and sanitization are: SQL injection (SQLI, Cross-Site Scripting (XSS and Buffer Overflow (BOF. In order to address these vulnerabilities we designed and developed the WAPTT (Web Application Penetration Testing Tool tool - web application penetration testing tool. Unlike other web application penetration testing tools, this tool is modular, and can be easily extended by end-user. In order to improve efficiency of SQLI vulnerability detection, WAPTT uses an efficient algorithm for page similarity detection. The proposed tool showed promising results as compared to six well-known web application scanners in detecting various web application vulnerabilities.

Penetrating power of resonant electromagnetic induction imaging

Directory of Open Access Journals (Sweden)

Roberta Guilizzoni

2016-09-01

Full Text Available The possibility of revealing the presence and identifying the nature of conductive targets is of central interest in many fields, including security, medicine, industry, archaeology and geophysics. In many applications, these targets are shielded by external materials and thus cannot be directly accessed. Hence, interrogation techniques are required that allow penetration through the shielding materials, in order for the target to be identified. Electromagnetic interrogation techniques represent a powerful solution to this challenge, as they enable penetration through conductive shields. In this work, we demonstrate the power of resonant electromagnetic induction imaging to penetrate through metallic shields (1.5-mm-thick and image targets (having conductivities σ ranging from 0.54 to 59.77 MSm−1 concealed behind them.

An investigation of the maximum penetration level of a photovoltaic (PV) system into a traditional distribution grid

Science.gov (United States)

Chalise, Santosh

Although solar photovoltaic (PV) systems have remained the fastest growing renewable power generating technology, variability as well as uncertainty in the output of PV plants is a significant issue. This rapid increase in PV grid-connected generation presents not only progress in clean energy but also challenges in integration with traditional electric power grids which were designed for transmission and distribution of power from central stations. Unlike conventional electric generators, PV panels do not have rotating parts and thus have no inertia. This potentially causes a problem when the solar irradiance incident upon a PV plant changes suddenly, for example, when scattered clouds pass quickly overhead. The output power of the PV plant may fluctuate nearly as rapidly as the incident irradiance. These rapid power output fluctuations may then cause voltage fluctuations, frequency fluctuations, and power quality issues. These power quality issues are more severe with increasing PV plant power output. This limits the maximum power output allowed from interconnected PV plants. Voltage regulation of a distribution system, a focus of this research, is a prime limiting factor in PV penetration levels. The IEEE 13-node test feeder, modeled and tested in the MATLAB/Simulink environment, was used as an example distribution feeder to analyze the maximum acceptable penetration of a PV plant. The effect of the PV plant's location was investigated, along with the addition of a VAR compensating device (a D-STATCOM in this case). The results were used to develop simple guidelines for determining an initial estimate of the maximum PV penetration level on a distribution feeder. For example, when no compensating devices are added to the system, a higher level of PV penetration is generally achieved by installing the PV plant close to the substation. The opposite is true when a VAR compensator is installed with the PV plant. In these cases, PV penetration levels over 50% may be

Simple Amides of Oleanolic Acid as Effective Penetration Enhancers

Science.gov (United States)

Bednarczyk-Cwynar, Barbara; Partyka, Danuta; Zaprutko, Lucjusz

2015-01-01

Transdermal transport is now becoming one of the most convenient and safe pathways for drug delivery. In some cases it is necessary to use skin penetration enhancers in order to allow for the transdermal transport of drugs that are otherwise insufficiently skin-permeable. A series of oleanolic acid amides as potential transdermal penetration enhancers was formed by multistep synthesis and the synthesis of all newly prepared compounds is presented. The synthetized amides of oleanolic acid were tested for their in vitro penetration promoter activity. The above activity was evaluated by means of using the Fürst method. The relationships between the chemical structure of the studied compounds and penetration activity are presented. PMID:26010090

Simple amides of oleanolic acid as effective penetration enhancers.

Science.gov (United States)

Bednarczyk-Cwynar, Barbara; Partyka, Danuta; Zaprutko, Lucjusz

2015-01-01

Transdermal transport is now becoming one of the most convenient and safe pathways for drug delivery. In some cases it is necessary to use skin penetration enhancers in order to allow for the transdermal transport of drugs that are otherwise insufficiently skin-permeable. A series of oleanolic acid amides as potential transdermal penetration enhancers was formed by multistep synthesis and the synthesis of all newly prepared compounds is presented. The synthetized amides of oleanolic acid were tested for their in vitro penetration promoter activity. The above activity was evaluated by means of using the Fürst method. The relationships between the chemical structure of the studied compounds and penetration activity are presented.

A novel methanol sensor based on gas-penetration through a porous polypyrrole-coated polyacrylonitrile nanofiber mat.

Science.gov (United States)

Jun, Tae-Sun; Ho, Thi Anh; Rashid, Muhammad; Kim, Yong Shin

2013-09-01

In this work, we propose a novel chemoresistive gas sensor operated under a vertical analyte flow passing through a permeable sensing membrane. Such a configuration is different from the use of a planar sensor implemented under a conventional horizontal flow. A highly porous core-shell polyacrylonitrile-polypyrrole (PAN@PPy) nanofiber mat was prepared as the sensing element via electrospinning and two-step vapor-phase polymerization (VPP). Various analysis methods such as SEM, TEM, FT-IR and XPS measurements were employed in order to characterize structural features of the porous sensing mat. These analyses confirmed that very thin (ca. 10 nm) conductive PPy sheath layers were deposited by VPP on electrospun PAN nanofibers with an average diameter of 258 nm. Preliminary results revealed that the gas penetration-type PAN@PPy sensor had a higher sensor response and shorter detection and recovery times upon exposure to methanol analyte when compared with a conventional horizontal flow sensor due to efficient and fast analyte transfer into the sensing layer.

Safety considerations of laser related penetration in LCTR central power stations

International Nuclear Information System (INIS)

Botts, T.E.; Chan, C.K.; Ullman, A.Z.

1976-01-01

The following topics are briefly described: (1) requirements for optical penetration performance, (2) failure sequences in LCTR optical penetrations, (3) thermal stress in optical penetrations, and (4) nonlinear optical effects

Importance Of Penetration Testing For Legacy Operating System

Directory of Open Access Journals (Sweden)

Poorvi Bhatt

2017-12-01

Full Text Available Penetration testing is very important technique to find vulnerabilities in commercial networks. There are various techniques for ethical hacking via penetration testing. This report explains a white hat hacker approach of penetration testing. I have performed this test on private network where three PCs are connected through LAN via switch and without firewall. This network is not connected with Internet. All the PCs have windows operating system. The attacker host has windows server 2003 with Service Pack1 second host has windows XP with Service Pack 2 and third host has windows 2000 with service pack 4.

Magnetic field penetration into superconductors with sharp edges

International Nuclear Information System (INIS)

Zhilichev, Yuriy N.

2003-01-01

The magnetic field and surface currents induced within a superconductor are calculated assuming the field penetrates in it near sharp corners. Rounding the corners is used to keep the field less than a critical value. Analytical formulas for a corner radius are given for a wire of the rectangular cross-section and a cylinder in the external magnetic field. A boundary integral method is used to calculate the boundary of the Meissner domain when the external field penetrates deep into the superconductor. The effect of degree of penetration on the magnetic moment of superconducting cylinders and wires is discussed

Estimating residual life of alloy 600 RPV penetrations

International Nuclear Information System (INIS)

Hunt, E.S.; White, G.A.; Pathania, R.; Arey, M.L.; Whitaker, D.E.

1996-01-01

Primary water stress corrosion cracking (PWSCC) of Alloy 600 penetrations PWR in reactor pressure vessel (RPV) heads has become a significant economic concern worldwide. PWSCC of these penetrations has led to extended maintenance outages, expensive inspections and repairs, and in some cases, replacement of the entire vessel head. This paper describes methodology developed to predict the remaining life of Alloy 600 penetrations in reactor vessel heads. Predictions of remaining life are an important input to planning models used by utilities to select a strategy for responding to the PWSCC issue at the lowest life cycle cost with an acceptably low risk of leakage. The remaining life of RPV penetrations is determined using the results of inspections of penetrations and statistical methods to predict future degradation. The analysis takes into account the effects of material properties, welding residual stresses, and operating temperature on PWSCC initiation and growth. The probability of developing cracks of various depths is assessed using Monte Carlo methods which provide for uncertainties in the input assumptions. For plants which have not yet performed inspections, remaining life predictions are based on inspection results from similar plants which have performed inspections with corrections made for known differences in design details, material properties and operating conditions

Dynamic hole closure behind a deep ocean sediment penetrator

International Nuclear Information System (INIS)

Dzwilewski, P.T.; Karnes, C.H.

1982-01-01

A freefall or boosted penetrator is one concept being considered to dispose of nuclear waste in the deep ocean seabed. For this technique to be acceptable, the sediment must be an effective barrier to the migration of radioactive nuclides, which means that the hole behind the advancing penetrator must close. One mechanism which can cause the hole to close immediately behind the penetrator is the reduction in water pressure in the wake as water tries to follow the penetrator into the sediment. An approximate solution to this complex problem is presented which analyzes the deformation of the sediment with a nonlinear, large displacement and strain, Lagrangian finite-difference computer code (STEALTH). The water was treated by Bernoulli's Principle for flow in a pipe resulting in a pressure boundary condition applied to the sediment surface along the path after passage of the penetrator. Two one-dimensional and eight two-dimensional calculations were performed with various penetrator velocities (15, 30, and 60 m/s) and sediment shear strengths. In two of the calculations, the dynamic pressure reduction was neglected to see if geostatic stresses alone would close the hole. The results of this study showed that geostatic stresses alone would not close the hole but the dynamic pressure reduction would. The largest uncertainty in the analysis was the pressure conditions in the water behind the penetrator in which frictionless, steady-state flow, in a uniform diameter pipe was assumed. A more sophisticated and realistic pressure condition has been formulated and will be implemented in the computer code in the near future

Fundamentals of ground penetrating radar in environmental and engineering applications

Energy Technology Data Exchange (ETDEWEB)

Casas, A.; Pinto, V.; Rivero, L. [Barcelona Univ., Barcelona (Spain). Faculty of Geology, Dept. of Geochemistry, Petrology and Geological Prospecting

2000-12-01

Ground Penetrating Radar (GPR) is a high frequency electromagnetic sounding technique that has been developed to investigate the shallow subsurface using the contrast of dielectric properties. The method operates on the simple principle that electromagnetic waves, emitted from a transmitter antenna, are reflected from buried objects and detected at another antenna, acting as receiver. GPR data is presented in the form of time-distance plots that are analogous to conventional reflection seismic records, and in fact the method has many similarities to seismic reflection method with a pulse of electromagnetic energy substituting for the elastic (seismic) energy. Nevertheless, the principles and theory of the method are based on the wave equation derived from Maxwell's equations for electromagnetic wave propagation. This paper has been written for tutorial purposes, and it is hoped that it will provide the reader with a good outline of GPR presenting an overview of its theoretical basis, guidelines for interpretation and some practical field examples.

Fundamentals of ground penetrating radar in environmental and engineering applications

International Nuclear Information System (INIS)

Casas, A.; Pinto, V.; Rivero, L.

2000-01-01

Ground Penetrating Radar (GPR) is a high frequency electromagnetic sounding technique that has been developed to investigate the shallow subsurface using the contrast of dielectric properties. The method operates on the simple principle that electromagnetic waves, emitted from a transmitter antenna, are reflected from buried objects and detected at another antenna, acting as receiver. GPR data is presented in the form of time-distance plots that are analogous to conventional reflection seismic records, and in fact the method has many similarities to seismic reflection method with a pulse of electromagnetic energy substituting for the elastic (seismic) energy. Nevertheless, the principles and theory of the method are based on the wave equation derived from Maxwell's equations for electromagnetic wave propagation. This paper has been written for tutorial purposes, and it is hoped that it will provide the reader with a good outline of GPR presenting an overview of its theoretical basis, guidelines for interpretation and some practical field examples

Fundamental of ground penetrating radar in environmental and engineering applications

Directory of Open Access Journals (Sweden)

L. Rivero

2000-06-01

Full Text Available Ground Penetrating Radar (GPR is a high frequency electromagnetic sounding technique that has been developed to investigate the shallow subsurface using the contrast of dielectric properties. The method operates on the simple principle that electromagnetic waves, emitted from a transmitter antenna, are reflected from buried objects and detected at another antenna, acting as receiver. GPR data is presented in the form of time-distance plots that are analogous to conventional reflection seismic records, and in fact the method has many similarities to seismic reflection method with a pulse of electromagnetic energy substituting for the elastic (seismic energy. Nevertheless, the principles and theory of the method are based on the wave equation derived from Maxwell's equations for electromagnetic wave propagation. This paper has been written for tutorial purposes, and it is hoped that it will provide the reader with a good outline of GPR presenting an overview of its theoretical basis, guidelines for interpretation and some practical field examples.

Risk assessment of electric generation systems with high wind penetration

International Nuclear Information System (INIS)

Salgado Duarte, Yorlandys; Castillo Serpa, Alfredo M. del

2017-01-01

The research evaluates the risk function of an Electric Generation System (SGE) with high wind power penetration using the Sequential Monte Carlo Simulation (SMCS) method, which allows calculating indicators that characterize the performance of the SGE with expected average values. The research uses a Markov model of two states or four states according to the characteristics of the generator to simulate the instantaneous capacity. The primary sources of each conventional generator are assumed to be always available; however, wind power depends on the wind behavior in each analyzed region. In this research, the Chronological Series and Weibull models are used to model the wind behavior, and the analyzes are performed in the IEEE-RTS system. The work shows that the behavior of the probabilistic indicators used to analyze the static capacity of the SGE is determined by the model used to simulate the stochastic of the generators and by the primary energy source. (author)

Replica scale modelling of long rod tank penetrators

NARCIS (Netherlands)

Diederen, A.M.; Hoeneveld, J.C.

2001-01-01

Experiments and simulations have been conducted using scale size tungsten alloy penetrators at ordnance velocity against an oblique plate array consisting of an inert sandwich and a base armour. The penetrators are made from 2 types of tungsten alloy with different tensile strength. Two scale sizes

The Impact of IPv6 on Penetration Testing

NARCIS (Netherlands)

Ottow, Christiaan; van Vliet, Frank; de Boer, Pieter-Tjerk; Pras, Aiko

In this paper we discuss the impact the use of IPv6 has on remote penetration testing of servers and web applications. Several modifications to the penetration testing process are proposed to accommodate IPv6. Among these modifications are ways of performing fragmentation attacks, host discovery and

Conditions for plasmoid penetration across abrupt magnetic barriers

International Nuclear Information System (INIS)

Brenning, Nils; Hurtig, Tomas; Raadu, Michael A.

2005-01-01

The penetration of plasma clouds, or plasmoids, across abrupt magnetic barriers (of the scale less than a few ion gyro radii, using the plasmoid directed velocity) is studied. The insight gained earlier, from detailed experimental and computer simulation investigations of a case study, is generalized into other parameter regimes. It is concluded for what parameters a plasmoid should be expected to penetrate the magnetic barrier through self-polarization, penetrate through magnetic expulsion, or be rejected from the barrier. The scaling parameters are n e , v 0 , B perpendicular , m i , T i , and the width w of the plasmoid. The scaling is based on a model for strongly driven, nonlinear magnetic field diffusion into a plasma which is a generalization of the earlier laboratory findings. The results are applied to experiments earlier reported in the literature, and also to the proposed application of impulsive penetration of plasmoids from the solar wind into the Earth's magnetosphere

Long-term behavior of aortic intramural hematomas and penetrating ulcers.

Science.gov (United States)

Chou, Alan S; Ziganshin, Bulat A; Charilaou, Paris; Tranquilli, Maryann; Rizzo, John A; Elefteriades, John A

2016-02-01

For intramural hematoma and penetrating atherosclerotic ulcer, long-term behavior and treatment are controversial. This study evaluates the long-term behavior of intramural hematoma and penetrating atherosclerotic ulcer, including radiologic follow-up and survival analysis. Between 1995 and 2014, 108 patients (mean age, 70.8 ± 10 years; 56% female) presented with intramural hematoma or penetrating atherosclerotic ulcer to Yale-New Haven Hospital (New Haven, Conn). We reviewed the medical records, radiology, and online mortality databases. Ten of 55 patients (18%) with intramural hematoma and 17 of 53 patients (32%) with penetrating atherosclerotic ulcer had rupture state symptoms on admission, both greater than type A (8%) or type B dissection (4%) (P hematoma with follow-up imaging, 8 of 14 (57%) worsened (mean follow-up, 9.4 months) and 6 (43%) underwent late surgery. For patients with penetrating atherosclerotic ulcer with follow-up imaging, 6 of 20 (30%) worsened and underwent late surgery, and 11 (55%) showed no change (mean follow-up, 34.3 months). Overall survivals were 77%, 70%, 58%, and 33% at 1, 3, 5, and 10 years, respectively. No operative deaths occurred for patients with nonrupture state. Patients with penetrating atherosclerotic ulcer with initial surgical treatment had better long-term survival than patients treated medically (P = .037). In the intramural hematoma group, no such difference was observed (P = .10). At presentation, the incidence of early rupture of intramural hematoma and penetrating atherosclerotic ulcer was higher than for typical dissection. For branch vessels, intramural hematoma never occludes branch arteries. On imaging follow-up, patients with intramural hematoma and penetrating atherosclerotic ulcer rarely improved, with late surgery commonly needed. Better survival was observed for the initial surgical management of patients with penetrating atherosclerotic ulcer compared with initial medical management. Copyright © 2016

Laser assisted robotic surgery in cornea transplantation

Science.gov (United States)

Rossi, Francesca; Micheletti, Filippo; Magni, Giada; Pini, Roberto; Menabuoni, Luca; Leoni, Fabio; Magnani, Bernardo

2017-03-01

Robotic surgery is a reality in several surgical fields, such as in gastrointestinal surgery. In ophthalmic surgery the required high spatial precision is limiting the application of robotic system, and even if several attempts have been designed in the last 10 years, only some application in retinal surgery were tested in animal models. The combination of photonics and robotics can really open new frontiers in minimally invasive surgery, improving the precision, reducing tremor, amplifying scale of motion, and automating the procedure. In this manuscript we present the preliminary results in developing a vision guided robotic platform for laser-assisted anterior eye surgery. The robotic console is composed by a robotic arm equipped with an "end effector" designed to deliver laser light to the anterior corneal surface. The main intended application is for laser welding of corneal tissue in laser assisted penetrating keratoplasty and endothelial keratoplasty. The console is equipped with an integrated vision system. The experiment originates from a clear medical demand in order to improve the efficacy of different surgical procedures: when the prototype will be optimized, other surgical areas will be included in its application, such as neurosurgery, urology and spinal surgery.

A robotic platform for laser welding of corneal tissue

Science.gov (United States)

Rossi, Francesca; Micheletti, Filippo; Magni, Giada; Pini, Roberto; Menabuoni, Luca; Leoni, Fabio; Magnani, Bernardo

2017-07-01

Robotic surgery is a reality in several surgical fields, such as in gastrointestinal surgery. In ophthalmic surgery the required high spatial precision is limiting the application of robotic system, and even if several attempts have been designed in the last 10 years, only some application in retinal surgery were tested in animal models. The combination of photonics and robotics can really open new frontiers in minimally invasive surgery, improving the precision, reducing tremor, amplifying scale of motion, and automating the procedure. In this manuscript we present the preliminary results in developing a vision guided robotic platform for laser-assisted anterior eye surgery. The robotic console is composed by a robotic arm equipped with an "end effector" designed to deliver laser light to the anterior corneal surface. The main intended application is for laser welding of corneal tissue in laser assisted penetrating keratoplasty and endothelial keratoplasty. The console is equipped with an integrated vision system. The experiment originates from a clear medical demand in order to improve the efficacy of different surgical procedures: when the prototype will be optimized, other surgical areas will be included in its application, such as neurosurgery, urology and spinal surgery.

HMO penetration and physicians' earnings.

Science.gov (United States)

Hadley, J; Mitchell, J M

1999-11-01

The goal of this study is to estimate whether cross-sectional variations in enrollment in health maintenance organizations (HMOs) affected physicians' earnings and hourly income in 1990. Using data from a nationally representative sample of 4,577 younger physicians (penetration is endogenous and used the instrumental variables approach to obtain unbiased estimates. HMO penetration had a negative and statistically significant impact on physicians earnings in 1990. A doubling of the average level of HMO penetration in the market is estimated to reduce annual earnings by 7% to 10.7%, and hourly earnings by approximately 6% to 9%. It appears that HMOs were successful in reducing physicians' annual and per hour earnings in 1990, presumably through a combination of fewer visits and lower payment rates for people covered by HMOs. Although these results cannot be generalized to all physicians, the experience of a younger cohort of physicians may still be a good indicator of the future effects of HMOs because younger physicians may be more susceptible to market forces than older and more established physicians. Moreover, these results may be somewhat conservative because they reflect market behavior in 1990, several years before the rapid growth and more aggressive market behavior of HMOs in recent years.

Hybrid treatment of penetrating aortic ulcer

International Nuclear Information System (INIS)

Lara, Juan Antonio Herrero; Martins-Romeo, Daniela de Araujo; Escudero, Carlos Caparros; Falcon, Maria del Carmen Prieto; Batista, Vinicius Bianchi; Vazquez, Rosa Maria Lepe

2015-01-01

Penetrating atherosclerotic aortic ulcer is a rare entity with poor prognosis in the setting of acute aortic syndrome. In the literature, cases like the present one, located in the aortic arch, starting with chest pain and evolving with dysphonia, are even rarer. The present report emphasizes the role played by computed tomography in the diagnosis of penetrating atherosclerotic ulcer as well as in the differentiation of this condition from other acute aortic syndromes. Additionally, the authors describe a new therapeutic approach represented by a hybrid endovascular surgical procedure for treatment of the disease. (author)

Hybrid treatment of penetrating aortic ulcer

Energy Technology Data Exchange (ETDEWEB)

Lara, Juan Antonio Herrero; Martins-Romeo, Daniela de Araujo; Escudero, Carlos Caparros; Falcon, Maria del Carmen Prieto; Batista, Vinicius Bianchi, E-mail: jaherrero5@hotmail.com [Unidade de Gestao Clinica (UGC) de Diagnostico por Imagem - Hosppital Universitario Virgen Macarena, Sevilha (Spain); Vazquez, Rosa Maria Lepe [Unit of Radiodiagnosis - Hospital Nuestra Senora de la Merced, Osuna, Sevilha (Spain)

2015-05-15

Penetrating atherosclerotic aortic ulcer is a rare entity with poor prognosis in the setting of acute aortic syndrome. In the literature, cases like the present one, located in the aortic arch, starting with chest pain and evolving with dysphonia, are even rarer. The present report emphasizes the role played by computed tomography in the diagnosis of penetrating atherosclerotic ulcer as well as in the differentiation of this condition from other acute aortic syndromes. Additionally, the authors describe a new therapeutic approach represented by a hybrid endovascular surgical procedure for treatment of the disease. (author)

Methane penetration in DIII-D ELMing H-mode plasmas

International Nuclear Information System (INIS)

West, W.P.; Lasnier, C.J.; Whyte, D.G.; Isler, R.C.; Evans, T.E.; Jackson, G.L.; Rudakov, D.; Wade, M.R.; Strachan, J.

2003-01-01

Carbon penetration into the core plasma during midplane and divertor methane puffing has been measured for DIII-D ELMing H-mode plasmas. The methane puffs are adjusted to a measurable signal, but global plasma parameters are only weakly affected (line average density, e > increases by E , drops by 6+ density profiles in the core measured as a function of time using charge exchange recombination spectroscopy. The methane penetration factor is defined as the difference in the core content with the puff on and puff off, divided by the carbon confinement time and the methane puffing rate. In ELMing H-mode discharges with ion ∇B drift direction into the X-point, increasing the line averaged density from 5 to 8x10 19 m -3 dropped the penetration factor from 6.6% to 4.6% for main chamber puffing. The penetration factor for divertor puffing was below the detection limit (<1%). Changing the ion ∇B drift to away from the X-point decreased the penetration factor by more than a factor of five for main chamber puffing

Double ionization chamber survey meter for the separate measurement of penetrating and non-penetrating dose

International Nuclear Information System (INIS)

Lucas, A.C.

1987-01-01

The full capabilities of an advanced 8-bit microprocessor have been utilized in construction of a wide range, multiplexing survey meter based on dual electrometers and ionization chambers. The ionization chambers are constructed of modular conducting and non-conducting parts in such a way that the angular dependence for measurement of beta radiation is controlled by design. Display functions for the high range instrument include logarithmic or linear analog display, digital display of rate or dose, SI or English units, optionally for either total, penetrating, or non-penetrating dose. The instrument is presently configured to operate in the range 0.1 R/hr to 50,000 R/hr in support of the requirements of Regulatory Guide 19.7

Videofluoroscopic Predictors of Penetration-Aspiration in Parkinson's Disease Patients.

Science.gov (United States)

Argolo, Natalie; Sampaio, Marília; Pinho, Patrícia; Melo, Ailton; Nóbrega, Ana Caline

2015-12-01

Parkinson's disease (PD) patients show a high prevalence of swallowing disorders and tracheal aspiration of food. The videofluoroscopic study of swallowing (VFSS) allows clinicians to visualize the visuoperceptual and temporal parameters associated with swallowing disorders in an attempt to predict aspiration risk. However, this subject remains understudied in PD populations. Our aim was to identify the predictors of penetration-aspiration in PD patients using the VFSS. Consecutive patients were evaluated using VFSS with different consistencies and volumes of food. A speech-language pathologist measured the type of intra-oral bolus organization, loss of bolus control, bolus location at the initiation of the pharyngeal swallow, the presence of multiple swallows, piecemeal deglutition, bolus residue in the pharyngeal recesses and temporal measures. Scores ≥3 on the penetration-aspiration scale (PAS) indicated the occurrence of penetration-aspiration. Using logistic marginal regression, we found that residue in the vallecula, residue in the upper esophageal sphincter and piecemeal deglutition were associated with penetration-aspiration (odds ratio (OR) = 4.09, 2.87 and 3.83; P = 0.0040, 0.0071 and 0.0009, respectively). Penetration/aspiration occurred only with fluids (both of thin and thick consistency), and no significant differences were observed between fluid types or food volumes. The mechanisms underlying dysphagia and penetration/aspiration in PD patients and indications for further studies are discussed.

Grid of the Future: Quantification of Benefits from Flexible Energy Resources in Scenarios With Extra-High Penetration of Renewable Energy

Energy Technology Data Exchange (ETDEWEB)

Bebic, Jovan [General Electric International, Inc., Schenectady, NY (United States). Energy Consulting; Hinkle, Gene [General Electric International, Inc., Schenectady, NY (United States). Energy Consulting; Matic, Slobodan [General Electric International, Inc., Schenectady, NY (United States). Energy Consulting; Schmitt, William [General Electric International, Inc., Schenectady, NY (United States). Energy Consulting

2015-01-15

The main objective of this study is to quantify the entitlement for system benefits attainable by pervasive application of flexible energy resources in scenarios with extra-high penetration of renewable energy. The quantified benefits include savings in thermal energy and reduction of CO₂ emissions. Both are primarily a result of displacement of conventional thermal generation by renewable energy production, but there are secondary improvements that arise from lowering operating reserves, removing transmission constraints, and by partially removing energy-delivery losses due to energy production by distributed solar. The flexible energy resources in the context of this study include energy storage and adjustable loads. The flexibility of both was constrained to a time horizon of one day. In case of energy storage this means that the state of charge is restored to the starting value at the end of each day, while for load this means that the daily energy consumed is maintained constant. The extra-high penetration of renewable energy in the context of this study means the level of penetration resulting in significant number of hours where instantaneous power output from renewable resources added to the power output from baseload nuclear fleet surpasses the instantaneous power consumption by the load.

Measurements of the London penetration depths in YBa sub 2 Cu sub 3 O sub x by means of muon spin rotation (. mu. SR) experiments

Energy Technology Data Exchange (ETDEWEB)

Puempin, B.; Keller, H.; Kuendig, W.; Odermatt, W.; Savic, I.M.; Schneider, J.W.; Simmler, H.; Zimmermann, P. (Physik-Inst., Univ. Zuerich (Switzerland)); Bednorz, J.G.; Maeno, Y.; Mueller, K.A.; Rossel, C. (IBM Research Div., Zuerich Research Lab., Rueschlikon (Switzerland)); Kaldis, E.; Rusiecki, S. (Lab. fuer Festkoerperphysik, ETH Zuerich (Switzerland)); Assmus, W.; Kowalewski, J. (Physikalisches Inst., Univ. Frankfurt (Germany, F.R.))

1989-12-01

To get accurate values of the London penetration depths in YBa{sub 2}Cu{sub 3}O{sub x}, {mu}SR measurements were performed on a high quality, sintered sample and a c-axis-oriented polycrystal. For the sintered sample the temperature dependence of the effective penetration depth {lambda}{sub eff} is well described by the two-fluid model, with {lambda}{sub eff}(0) = 155(10) nm. This behavior of {lambda}{sub eff}(T) is consistent with conventional s-wave pairing. The anisotropy ratio {lambda}{sub c}/{lambda}{sub ab} {approx equal} 5(1) was determined from measurements on the polycrystal. These results were used to calculate {lambda}{sub ab}(0) = 130(10) nm and {lambda}{sub c}(0) {approx equal} 500-800 nm. (orig.).

Penetrating Cardiac and Hepatic Injury; Polytrauma of a Child After Bombing

Directory of Open Access Journals (Sweden)

Baris Akca

2013-10-01

Full Text Available After a bombing attack, patients were brought into hospital suffering from a combination of injuries caused by the blast, penetrating injuries and burns which as a case of polytrauma. In penetrating thoracoabdominal injuries due to bombing possibility of cardiac injury should be kept in mind. Penetrating cardiac injuries in children are rare but has a high mortality and morbidity. In some cases there may be difficulty in diagnosis of penetrating cardiac injury. In this case we want to share the diagnosis, treatment and follow-up processes of penetrating cardiac and hepatic injury with burns of a politrauma child due to bombing.

Cutaneous mucormycosis secondary to penetrative trauma.

Science.gov (United States)

Zahoor, Bilal; Kent, Stephen; Wall, Daryl

2016-07-01

Mucormycosis is a rare but serious sequelae of penetrating trauma [1-5]. In spite of aggressive management, mortality remains high due to dissemination of infection. We completed a review of literature to determine the most optimal treatment of cutaneous mucormycosis which occurs secondary to penetrating trauma. We completed a review regarding the management of mucormycosis in trauma patients. We selected a total of 36 reports, of which 18 were case-based, for review. Surgical debridement is a primary predictor of improved outcomes in the treatment of mucormycosis [3,6,7]. Anti-fungal therapy, especially lipid soluble formulation of Amphotericin B, is helpful as an adjunct or when surgical debridement has been maximally achieved. Further research is needed to fully evaluate the impact of topical dressings; negative pressure wound therapy is helpful. An aggressive and early surgical approach, even at the expense of disfigurement, is necessary to reduce mortality in the setting of cutaneous mucormycosis that results from penetrating trauma [4,8,9]. Anti-fungal therapy and negative pressure wound therapy are formidable adjuncts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Organ culture storage of pre-prepared corneal donor material for Descemet's membrane endothelial keratoplasty.

Science.gov (United States)

Bhogal, Maninder; Matter, Karl; Balda, Maria S; Allan, Bruce D

2016-11-01

To evaluate the effect of media composition and storage method on pre-prepared Descemet's membrane endothelial keratoplasty (DMEK) grafts. 50 corneas were used. Endothelial wound healing and proliferation in different media were assessed using a standard injury model. DMEK grafts were stored using three methods: peeling with free scroll storage; partial peeling with storage on the stroma and fluid bubble separation with storage on the stroma. Endothelial cell (EC) phenotype and the extent of endothelial overgrowth were examined. Global cell viability was assessed for storage methods that maintained a normal cell phenotype. 1 mm wounds healed within 4 days. Enhanced media did not increase EC proliferation but may have increased EC migration into the wounded area. Grafts that had been trephined showed evidence of EC overgrowth, whereas preservation of a physical barrier in the bubble group prevented this. In grafts stored in enhanced media or reapposed to the stroma after trephination, endothelial migration occurred sooner and cells underwent endothelial-mesenchymal transformation. Ongoing cell loss, with new patterns of cell death, was observed after returning grafts to storage. Grafts stored as free scrolls retained more viable ECs than grafts prepared with the fluid bubble method (74.2± 3% vs 60.3±6%, p=0.04 (n=8). Free scroll storage is superior to liquid bubble and partial peeling techniques. Free scrolls only showed overgrowth of ECs after 4 days in organ culture, indicating a viable time window for the clinical use of pre-prepared DMEK donor material using this method. Methods for tissue preparation and storage media developed for whole corneas should not be used in pre-prepared DMEK grafts without prior evaluation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

A comparison of conventional mechanical testing techniques with innovative testing techniques for the evaluation of mechanical properties of NPP structural materials

International Nuclear Information System (INIS)

Liddell, P.A.; Kopriva, R.

2015-01-01

The innovative testing methods of Small Punch (SP) and Automated Ball Indentation (ABI) tests are based on the determination of material properties from sub-sized samples. These methods are promising to evaluate the components of nuclear power plants since they preserve the structural integrity of the component. The SP test is a semi-destructive method that employs miniaturised plate-shaped samples of various geometries. The method is based on the penetration of a sample with a semi-spherical punch. The sample deflection is measured throughout the test. The ABI test is a fully automatic test based on multiple indentations at a single penetration location on a polished sample surface with a spherical indenter of various diameters. The purpose of the test is to determine the tensile properties of materials in a non-destructive and localised fashion. A comparison has been made between SP, ABI and conventional tensile tests on the measurement of yield strength for the A533B (JRQ) ferritic steel which is a base metal of the pressure vessels of western PWR. The results show an excellent correlation for both innovative methods and the conventional tensile tests

Wireless Network Penetration Testing and Security Auditing

Directory of Open Access Journals (Sweden)

Wang Shao-Long

2016-01-01

Full Text Available IEEE802.11 wireless wireless networks have security issues that are vulnerable to a variety of attacks. Due to using radio to transport data, attackers can bypass firewalls, sniff sensitive information, intercept packets and send malicious packets. Security auditing and penetration testing is expected to ensure wireless networks security. The contributions of this work are analyzed the vulnerability and types of attacks pertaining to IEEE 802.11 WLAN, performed well known attacks in a laboratory environment to conduct penetration tests to confirm whether our wireless network is hackable or not. WAIDPS is configured as auditing tool to view wireless attacks, such as WEP/WPA/WPA2 cracking, rouge access points, denial of service attack. WAIDPS is designed to detect wireless intrusion with additional features. Penetration testing and auditing will mitigate the risk and threatening to protect WALN.

Penetrating chest injury: A miraculous life salvage

Directory of Open Access Journals (Sweden)

Santosh B Dalavi

2013-01-01

Full Text Available An unusual penetrating chest injury was caused by high velocity road traffic accident. An 18-year-old had a four wheeler accident and was brought in emergency department with a ′bamboo′ stick on the left side chest exiting through back. After the stabilization of vital parameters, an inter-costal tube drainage was done on the left side. Except the minor brochopleural fistula which healed by 10 th day, his recovery was uneventful. The outcome was consistent with current aggressive management of penetrating chest injuries. Management of penetrating chest injury involving pulmonary trauma is based on three principles. One is stabilization of hemodynamics of patient with proper clinical evaluation. Second, a mere intercostal tube drainage sufficient for majority of the cases. Third, post-operative active as well as passive physiotherapy is necessary for speedy recovery.

Characteristics of rain penetration through a gravity ventilator used for natural ventilation.

Science.gov (United States)

Kim, Taehyeung; Lee, Dong Ho; Ahn, Kwangseog; Ha, Hyunchul; Park, Heechang; Piao, Cheng Xu; Li, Xiaoyu; Seo, Jeoungyoon

2008-01-01

Gravity ventilators rely simply on air buoyancy to extract air and are widely used to exhaust air contaminants and heat from workplaces using minimal energy. They are designed to maximize the exhaust flow rate, but the rain penetration sometimes causes malfunctioning. In this study, the characteristics of rain penetration through a ventilator were examined as a preliminary study to develop a ventilator with the maximum exhaust capacity while minimizing rain penetration. A model ventilator was built and exposed to artificial rain and wind. The paths, intensities and amounts of penetration through the ventilator were observed and measured in qualitative and quantitative fashions. In the first phase, the pathways and intensities of rain penetration were visually observed. In the second phase, the amounts of rain penetration were quantitatively measured under the different configurations of ventilator components that were installed based on the information obtained in the first-phase experiment. The effects of wind speed, grill direction, rain drainage width, outer wall height, neck height and leaning angle of the outer wall from the vertical position were analyzed. Wind speed significantly affected rain penetration. Under the low crosswind conditions, the rain penetration intensities were under the limit of detection. Under the high crosswind conditions, grill direction and neck height were the most significant factors in reducing rain penetration. The installation of rain drainage was also important in reducing rain penetration. The experimental results suggest that, with proper configurations of its components, a gravity ventilator can be used for natural ventilation without significant rain penetration problems.

Percutaneous penetration of 3H-Huangbai extracts and H3-berberine

International Nuclear Information System (INIS)

Jin Xipeng; Yu Xiaozhong; Zhang Nianbao; Kuang Jianwen

1992-01-01

The percutaneous penetration of 3 H-huangbai extracts and 3 H-berberine through excised guinea pig and human shins was studied using the static diffusion cell technique. The data were treated with mathematical model of skin absorption. The results showed that huangbai extracts and berberine could penetrate the guinea pig and human skins at (above) dose of 8.38 μg/cm 2 and 14.32 μg/cm 2 , respectively. The amount and rate of penetration increased linearly with the time of exposure and dose. The permeability of berberine through guinea pig and human skins in two vehicles (water and glycol) was lower than that of huangbai extracts. When Huangbai extracts and berberine were applied in glycol solution, the vehicle greatly enhanced the penetration of the two penetrant. The lag time of two penetrant through human skin was longer than that through guinea pig skin

Barbs facilitate the helical penetration of honeybee (Apis mellifera ligustica) stingers.

Science.gov (United States)

Wu, Jianing; Yan, Shaoze; Zhao, Jieliang; Ye, Yuying

2014-01-01

The stinger is a very small and efficient device that allows honeybees to perform two main physiological activities: repelling enemies and laying eggs for reproduction. In this study, we explored the specific characteristics of stinger penetration, where we focused on its movements and the effects of it microstructure. The stingers of Italian honeybees (Apis mellifera ligustica) were grouped and fixed onto four types of cubic substrates, before pressing into different substrates. The morphological characteristics of the stinger cross-sections were analyzed before and after penetration by microscopy. Our findings suggest that the honeybee stinger undergoes helical and clockwise rotation during penetration. We also found that the helical penetration of the stinger is associated directly with the spiral distribution of the barbs, thereby confirming that stinger penetration involves an advanced microstructure rather than a simple needle-like apparatus. These results provide new insights into the mechanism of honeybee stinger penetration.

Conducting network penetration and espionage in a global environment

CERN Document Server

Middleton, Bruce

2014-01-01

When it's all said and done, penetration testing remains the most effective way to identify security vulnerabilities in computer networks. Conducting Network Penetration and Espionage in a Global Environment provides detailed guidance on how to perform effective penetration testing of computer networks-using free, open source, and commercially available tools, including Backtrack, Metasploit, Wireshark, Nmap, Netcat, and Nessus. It also considers exploits and other programs using Python, PERL, BASH, PHP, Ruby, and Windows PowerShell.The book taps into Bruce Middleton's decades of experience wi

The Effect and Mechanism of Transdermal Penetration Enhancement of Fu's Cupping Therapy: New Physical Penetration Technology for Transdermal Administration with Traditional Chinese Medicine (TCM) Characteristics.

Science.gov (United States)

Xie, Wei-Jie; Zhang, Yong-Ping; Xu, Jian; Sun, Xiao-Bo; Yang, Fang-Fang

2017-03-27

In this paper, a new type of physical penetration technology for transdermal administration with traditional Chinese medicine (TCM) characteristics is presented. Fu's cupping therapy (FCT), was established and studied using in vitro and in vivo experiments and the penetration effect and mechanism of FCT physical penetration technology was preliminarily discussed. With 1-(4-chlorobenzoyl)-5-methoxy-2-methylindole-3-ylacetic acid (indomethacin, IM) as a model drug, the establishment of high, medium, and low references was completed for the chemical permeation system via in vitro transdermal tests. Furthermore, using chemical penetration enhancers (CPEs) and iontophoresis as references, the percutaneous penetration effect of FCT for IM patches was evaluated using seven species of in vitro diffusion kinetics models and in vitro drug distribution; the IM quantitative analysis method in vivo was established using ultra-performance liquid chromatography-tandem mass spectrometry technology (UPLC-MS/MS), and pharmacokinetic parameters: area under the zero and first moment curves from 0 to last time t (AUC 0-t , AUMC 0-t ), area under the zero and first moment curves from 0 to infinity (AUC 0-∞ , AUMC 0-∞ ), maximum plasma concentration (C max ) and mean residence time (MRT), were used as indicators to evaluate the percutaneous penetration effect of FCT in vivo. Additionally, we used the 3 K factorial design to study the joint synergistic penetration effect on FCT and chemical penetration enhancers. Through scanning electron microscopy (SEM) and transmission electron microscope (TEM) imaging, micro- and ultrastructural changes on the surface of the stratum corneum (SC) were observed to explore the FCT penetration mechanism. In vitro and in vivo skin permeation experiments revealed that both the total cumulative percutaneous amount and in vivo percutaneous absorption amount of IM using FCT were greater than the amount using CPEs and iontophoresis. Firstly, compared with

Field Test Evaluation of Effect on Cone Resistance Caused by Change in Penetration Rate

DEFF Research Database (Denmark)

Poulsen, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

2012-01-01

in the laboratory. A change in the measured cone resistance occurs by lowering the penetration rate. This is caused by the changes in drainage conditions. Compared to the normal penetration rate of 20 mm/s, this paper illustrates that lowering the penetration rate leads to an increase in the cone resistance from 1......This paper presents how a change in cone penetration rate affects the measured cone resistance during cone penetration testing in silty soils. Regardless of soil, type the standard rate of penetration is 20 mm/s and it is generally accepted that undrained penetration occurs in clay while drained...... penetration occurs in sand. In intermediate soils such as silty soils, the standard cone penetration rate may result in drainage conditions varying from undrained to partially or fully drained conditions. Field cone penetrations tests have been conducted with different penetration rates on a test site...

Participation of Flexible Loads in Load Frequency Control to Support High Wind Penetration

DEFF Research Database (Denmark)

Uslu, Umur; Zhang, Boyang; Pillai, Jayakrishnan Radhakrishna

2016-01-01

The increasing amount of fluctuating wind power penetration in power systems presents many challenges to its operation and control. The new wind power plants are replacing many of the conventional large power plants that ensure power balancing and ancillary services for stable and reliable...... operation of the grid. Therefore, new solutions for power balancing reserves have to be explored and utilized by the grid utilities. To meet these challenges, large sizable loads like alkaline electrolysers, heat pumps and electric vehicles which are gaining popularity can provide system support to the grid...... through their inherent flexibility and energy storage characteristics. This paper investigates the possibilities and potential of such flexible loads to participate in power system frequency regulation in a wind dominated power system. The results show that these consumption units provide better...

Experience With The Management Of unusual Penetrating Chest ...

African Journals Online (AJOL)

The presentation shows how a victim of fall from height in the bush can sustain a penetrating chest injury on a dry stick of a shrub. Applications on the principles of management of penetrating chest injury is needed despite the grotesque clinical appearance. [Jnl College of Medicine Vol.7(1) 2002: 40-42] ...

An explosive acoustic telemetry system for seabed penetrators

Energy Technology Data Exchange (ETDEWEB)

Hauser, G.C.; Hickerson, J.

1988-04-01

This report discusses the design and past applications of an explosive acoustic telemetry system (EATS) for gathering and transmitting data from seabed penetrators. The system was first fielded in 1982 and has since been used to measure penetrator performance on three other occasions. Descriptions are given of the mechanical hardware, system electronics, and software.

Operational experience of extreme wind penetrations

Energy Technology Data Exchange (ETDEWEB)

Estanqueiro, Ana [INETI/LNEG - National Laboratory for Energy and Geology, Lisbon (Portugal); Mateus, Carlos B. [Instituto de Meteorologia, Lisboa (Portugal); Pestana, Rui [Redes Energeticas Nacionais (REN), Lisboa (Portugal)

2010-07-01

This paper reports the operational experience from the Portuguese Power System during the 2009/2010 winter months when record wind penerations were observed: the instantaneous wind power penetration peaked at 70% of consumption during no-load periods and the wind energy accounted for more than 50% of the energy consumed for a large period. The regulation measures taken by the TSO are presented in the paper, together with the additional reserves operated for added system security. Information on the overall power system behavior under such extreme long-term wind power penetrations will also be addressed. (org.)

Generic Penetration of the SSRI Market.

Science.gov (United States)

Cascade, Elisa F; Kalali, Amir H

2008-04-01

In this article, we investigate the penetration of generic selective serotonin reuptake inhibitors (SSRIs) in the US market and the implications for patient out-of-pocket expense. The data suggest that generic penetration into the SSRI market has grown from approximately nine percent in 2000, the year that the patent for Prozac((R)) expired, to 72 percent in 2007. For December, 2007, the difference in patient out-of-pocket expense for branded vs. generic agents was, on average, $55.42 for patients paying by cash (i.e., they had no prescription drug insurance) and $22.39 for patients with insurance coverage.

Penetrating ocular trauma from trampoline spring.

Science.gov (United States)

Spokes, David; Siddiqui, Salina; Vize, Colin

2010-02-01

The case is presented of a 12-year old boy who sustained severe penetrating ocular trauma while playing on a domestic trampoline. A main spring broke under tension and the hook had struck the eye at high velocity and penetrated the sclera. Primary repair was undertaken but on review it became apparent the eye could not be salvaged. Evisceration was carried out and an orbital implant was placed. Post-operative cosmesis is acceptable. This type of injury has not been reported before. Adult supervision of children on trampolines is recommended to minimise the chance of serious injury.

Air Versus Sulfur Hexafluoride Gas Tamponade in Descemet Membrane Endothelial Keratoplasty: A Fellow Eye Comparison.

Science.gov (United States)

von Marchtaler, Philipp V; Weller, Julia M; Kruse, Friedrich E; Tourtas, Theofilos

2018-01-01

To perform a fellow eye comparison of outcomes and complications when using air or sulfur hexafluoride (SF6) gas as a tamponade in Descemet membrane endothelial keratoplasty (DMEK). One hundred thirty-six eyes of 68 consecutive patients who underwent uneventful DMEK in both eyes for Fuchs endothelial corneal dystrophy were included in this retrospective study. Inclusion criteria were air tamponade (80% of the anterior chamber volume) in the first eye and 20% SF6 gas tamponade (80% of the anterior chamber volume) in the second eye; and same donor tissue culture condition in both eyes. All eyes received laser iridotomy on the day before DMEK. Main outcome measures included preoperative and postoperative best-corrected visual acuity, endothelial cell density, corneal volume, rebubbling rate, and rate of postoperative pupillary block caused by the air/gas bubble. Thirteen of 68 eyes (19.1%) with an air tamponade needed rebubbling compared with 4 of 68 eyes (5.9%) with an SF6 gas tamponade (P = 0.036). Postoperative pupillary block necessitating partial release of air/gas occurred in 1 eye (1.5%) with an air tamponade and 3 eyes (4.4%) with an SF6 gas tamponade (P = 0.301). There were no significant differences in preoperative and postoperative best-corrected visual acuity, endothelial cell density, and corneal volume within 3-month follow-up. Our results confirm the previously reported better graft adhesion when using an SF6 gas tamponade in DMEK without increased endothelial cell toxicity. The rate of pupillary block in eyes with an SF6 gas tamponade was comparable to that with an air tamponade. As a consequence, we recommend using SF6 gas as the tamponade in DMEK.

Standardization of the Descemet membrane endothelial keratoplasty technique: Outcomes of the first 450 consecutive cases.

Science.gov (United States)

Satué, M; Rodríguez-Calvo-de-Mora, M; Naveiras, M; Cabrerizo, J; Dapena, I; Melles, G R J

2015-08-01

To evaluate the clinical outcome of the first 450 consecutive cases after Descemet membrane endothelial keratoplasty (DMEK), as well as the effect of standardization of the technique. Comparison between 3 groups: Group I: (cases 1-125), as the extended learning curve; Group II: (cases 126-250), transition to technique standardization; Group III: (cases 251-450), surgery with standardized technique. Best corrected visual acuity, endothelial cell density, pachymetry and intra- and postoperative complications were evaluated before, and 1, 3 and 6 months after DMEK. At 6 months after surgery, 79% of eyes reached a best corrected visual acuity of≥0.8 and 43%≥1.0. Mean preoperative endothelial cell density was 2,530±220 cells/mm2 and 1,613±495 at 6 months after surgery. Mean pachymetry measured 668±92 μm and 526±46 μm pre- and (6 months) postoperatively, respectively. There were no significant differences in best corrected visual acuity, endothelial cell density and pachymetry between the 3 groups (P > .05). Graft detachment presented in 17.3% of the eyes. The detachment rate declined from 24% to 12%, and the rate of secondary surgeries from 9.6% to 3.5%, from group I to III respectively. Visual outcomes and endothelial cell density after DMEK are independent of the technique standardization. However, technique standardization may have contributed to a lower graft detachment rate and a relatively low number of secondary interventions required. As such, DMEK may become the first choice of treatment in corneal endothelial disease. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

Topographic hot spot before descemet stripping automated endothelial keratoplasty is associated with postoperative hyperopic shift.

Science.gov (United States)

Shimizu, Tsutomu; Yamaguchi, Takefumi; Satake, Yoshiyuki; Shimazaki, Jun

2015-03-01

The aim of this study was to investigate topographic "hot spots" on the anterior corneal surface before Descemet stripping automated endothelial keratoplasty (DSAEK) and their effects on postoperative visual acuity and hyperopic shift. Twenty-seven eyes of 27 patients with bullous keratopathy, who underwent DSAEK were studied. We defined a hot spot as a focal area with relatively high refractive power on the anterior corneal surface in eyes with bullous keratopathy. Refractive spherical equivalent, keratometric value, and corneal topography were retrospectively evaluated using anterior segment optical coherence tomography (AS-OCT). Hot spots were identified in 11 eyes (42.3%) before DSAEK and disappeared in 9 eyes of these eyes (81.8%) at 6 months after DSAEK. AS-OCT revealed focal epithelial thickening in the same areas as the hot spots. There was no significant difference in the postoperative visual acuity between eyes with and without hot spots (P > 0.05). The keratometric value of the anterior corneal surface significantly flattened from 45.7 ± 2.7 diopters (D) before DSAEK to 44.2 ± 2.7 D 1 month after DSAEK in eyes with hot spots (P = 0.01), whereas in eyes without hot spots, there were no significant differences in the keratometric values before and after DSAEK. At 6 months, the refractive change was +1.1 ± 1.3 D in eyes with hot spots and -0.2 ± 0.6 D in eyes without hot spots (P = 0.034). In eyes with focal epithelial thickening, topographic hot spots on the anterior corneal surface were observed using AS-OCT. The hot spots disappeared after DSAEK and had no influence on the postoperative visual acuity.

Fire barrier penetration seals in nuclear power plants

International Nuclear Information System (INIS)

Bajwa, C.S.; West, K.S.

1996-07-01

NNPs are divided into separated fire areas by fire-rated structural barriers. Fire-rated penetration seals are installed to seal certain openings in these barriers, in order to provide reasonable assurance that a fire will be confined to the area where it started. The staff of the Fire Protection Engineering Section, Office of Nuclear Reactor Regulation, US NRC, conducted a comprehensive technical assessment of penetration seals to address reports of potential problems, to determine if there were any problems of safety significance, and to determine if NRC requirements, review guidance, and inspection procedures are adequate. It was concluded that the general condition of penetration seal programs in industry is satisfactory, and that the actions taken in 1988 and 1994 had increased industry awareness of potential problems and resulted in more thorough surveillances, maintenance, and corrective actions. These previous staff actions, together with continued licensee upkeep of existing penetration seal programs and continued NRC inspections, are adequate to maintain public health and safety. Several minor revisions to the NRC fire protection regulation and review guidance are recommended

Determining Hermeticity of Electron Devices by Dye Penetration

CERN Document Server

American Society for Testing and Materials. Philadelphia

1972-01-01

1.1 These practices cover procedures that will normally detect and locate the sites of gross leaks in electron devices. 1.2 These procedures are suitable for use on selected parts during receiving inspection or to verify and locate leakage sites for production control. They are not quantitative; no indication of leak size can be inferred from the test. 1.3 These procedures are most suitable for use on transparent glass-encased devices; all methods are applicable to transparent parts with an internal cavity. Method A, Penetrant-Capillary, is also applicable to parts, such as terminals, end seals or base assemblies, without an internal cavity, and Method C, Penetrant-Pressure Followed by Vacuum, can be used on opaque parts with an internal cavity. Method B, Penetrant-Pressure, can also be used on opaque parts with an internal cavity if the part is opened after dye penetration and before inspection. Parts that have an internal cavity may either contain gas (such as air, nitrogen, nitrogen-helium mixture, etc.) o...

Primary repair of penetrating colon injuries: a systematic review.

Science.gov (United States)

Singer, Marc A; Nelson, Richard L

2002-12-01

Primary repair of penetrating colon injuries is an appealing management option; however, uncertainty about its safety persists. This study was conducted to compare the morbidity and mortality of primary repair with fecal diversion in the management of penetrating colon injuries by use of a meta-analysis of randomized, prospective trials. We searched for prospective, randomized trials in MEDLINE (1966 to November 2001), the Cochrane Library, and EMBase using the terms colon, penetrating, injury, colostomy, prospective, and randomized. Studies were included if they were randomized, controlled trials that compared the outcomes of primary repair with fecal diversion in the management of penetrating colon injuries. Five studies were included. Reviewers performed data extraction independently. Outcomes evaluated from each trial included mortality, total complications, infectious complications, intra-abdominal infections, wound complications, penetrating abdominal trauma index, and length of stay. Peto odds ratios for combined effect were calculated with a 95 percent confidence interval for each outcome. Heterogeneity was also assessed for each outcome. The penetrating abdominal trauma index of included subjects did not differ significantly between studies. Mortality was not significantly different between groups (odds ratio, 1.70; 95 percent confidence interval, 0.51-5.66). However, total complications (odds ratio, 0.28; 95 percent confidence interval, 0.18-0.42), total infectious complications (odds ratio, 0.41; 95 percent confidence interval, 0.27-0.63), abdominal infections including dehiscence (odds ratio, 0.59; 95 percent confidence interval, 0.38-0.94), abdominal infections excluding dehiscence (odds ratio, 0.52; 95 percent confidence interval, 0.31-0.86), wound complications including dehiscence (odds ratio, 0.55; 95 percent confidence interval, 0.34-0.89), and wound complications excluding dehiscence (odds ratio, 0.43; 95 percent confidence interval, 0

Orientation dependence of deformation and penetration behavior of tungsten single-crystal rods

International Nuclear Information System (INIS)

Bruchey, W.J.; Horwath, E.J.; Kingman, P.W.

1991-01-01

This paper reports on the performance of tungsten single crystals as kinetic energy penetrator materials that was investigated in a high length-to-diameter (L/D) rod geometry at sub-scale (1/4 geometric scale). The [111]. [110], and [100] crystal orientations were tested in this 74-g LD = 15 geometry penetrator (6.90-mm diameter x 102.5-mm length). Several 93% tungsten alloy and uranium 3/4 titanium rod geometries were also tested to baseline expected performance of typical penetrator material/geometry combinations. Performance was determined for semi-infinite penetration into RHA steel and finite penetration into 76.20-mm RHA steel. Of the orientation tested, the [100] orientation provided the best ballistic results, with superior performance to mass and geometric equivalent 93% tungsten alloy rods. The [100] orientation also provided similar performance to geometric equivalent uranium 3/4 titanium rods. Favorable slip/cleavage during the compressive loading of the penetration process to allow penetrator material flow without large scale plastic deformation, and final shear localization at a favorable angle for easy material flow away from the penetration interface, contribute to the [100] orientation crystals' excellent performance. The net result was less energy expenditure during penetrator flow and, therefore, more energy for deformation of RHA

UO2/magnetite concrete interaction and penetration study

International Nuclear Information System (INIS)

Farhadieh, R.; Purviance, R.; Carlson, N.

1983-01-01

The concrete structure represents a line of defense in safety assessment of containment integrity and possible minimization of radiological releases following a reactor accident. The penetration study of hot UO 2 particles into limestone concrete and basalt concrete highlighted some major differences between the two concretes. These included penetration rate, melting and dissolution phenomena, released gases, pressurization of the UO 2 chamber, and characteristics of post-test concrete. The present study focuses on the phenomena associated with core debris interaction with and penetration into magnetite type concrete. The real material experiment was carried out with UO 2 particles and magnetite concrete in a test apparatus similar to the one utilized in the UO 2 /limestone experiment

Variance reduction methods applied to deep-penetration problems

International Nuclear Information System (INIS)

Cramer, S.N.

1984-01-01

All deep-penetration Monte Carlo calculations require variance reduction methods. Before beginning with a detailed approach to these methods, several general comments concerning deep-penetration calculations by Monte Carlo, the associated variance reduction, and the similarities and differences of these with regard to non-deep-penetration problems will be addressed. The experienced practitioner of Monte Carlo methods will easily find exceptions to any of these generalities, but it is felt that these comments will aid the novice in understanding some of the basic ideas and nomenclature. Also, from a practical point of view, the discussions and developments presented are oriented toward use of the computer codes which are presented in segments of this Monte Carlo course

A Study of Crystalline Mechanism of Penetration Sealer Materials.

Science.gov (United States)

Teng, Li-Wei; Huang, Ran; Chen, Jie; Cheng, An; Hsu, Hui-Mi

2014-01-14

It is quite common to dispense a topping material like crystalline penetration sealer materials (CPSM) onto the surface of a plastic substance such as concrete to extend its service life span by surface protections from outside breakthrough. The CPSM can penetrate into the existing pores or possible cracks in such a way that it may form crystals to block the potential paths which provide breakthrough for any unknown materials. This study investigated the crystalline mechanism formed in the part of concrete penetrated by the CPSM. We analyzed the chemical composites, in order to identify the mechanism of CPSM and to evaluate the penetrated depth. As shown in the results, SEM observes the acicular-structured crystals filling capillary pores for mortar substrate of the internal microstructure beneath the concrete surface; meanwhile, XRD and FT-IR showed the main hydration products of CPSM to be C-S-H gel and CaCO₃. Besides, MIP also shows CPSM with the ability to clog capillary pores of mortar substrate; thus, it reduces porosity, and appears to benefit in sealing pores or cracks. The depth of CPSM penetration capability indicated by TGA shows 0-10 mm of sealer layer beneath the concrete surface.

Penetration, Post-penetration Development, and Reproduction of Meloidogyne incognita on Cucumis melo var. texanus.

Science.gov (United States)

Faske, T R

2013-03-01

Cucumis melo var. texanus, a wild melon commonly found in the southern United States and two accessions, Burleson Co. and MX 1230, expressed resistance to Meloidogyne incognita in preliminary experiments. To characterize the mechanism of resistance, we evaluated root penetration, post-penetration development, reproduction, and emigration of M. incognita on these two accessions of C. melo var. texanus. Additionally, we evaluated 22 accessions of C. melo var. texanus for their reaction against M. incognita in a greenhouse experiment. Fewer (P ≤ 0.05) J2 penetrated the root system of C. melo var. texanus accessions (Burleson Co. and MX 1230) and C. metuliferus (PI 482452) (resistant control), 7 days after inoculation (DAI) than in C. melo 'Hales Best Jumbo' (susceptible control). A delayed (P ≤ 0.05) rate of nematode development was observed at 7, 14, and 21 DAI that contributed to lower (P ≤ 0.05) egg production on both accessions and C. metuliferus compared with C. melo. Though J2 emigration was observed on all Cucumis genotypes a higher (P ≤ 0.05) rate of J2 emigration was observed from 3 to 6 DAI on accession Burleson Co. and C. metuliferus than on C. melo. The 22 accessions of C. melo var. texanus varied relative to their reaction to M. incognita with eight supporting similar levels of nematode reproduction to that of C. metuliferus. Cucumis melo var. texanus may be a useful source of resistance against root-knot nematode in melon.

Spatiotemporal Dynamics of Soil Penetration Resistance of Recultivated Soil

Directory of Open Access Journals (Sweden)

Zadorozhnaya Galina

2018-03-01

Full Text Available This article examines changes in the spatial distribution of soil penetration resistance in ordinary chernozem (Calcic Chernozem and in the recultivated soil in 2012 and 2014. The measurements were carried out in the field using an Eijkelkamp penetrometer on a regular grid. The depth of measurement was 50 cm, the interval was 5 cm. The indices of variation of soil penetration resistance in space and time have been determined. The degree of spatial dependence of soil penetration resistance has been determined layer by layer. The nature of temporal dynamics of soil penetration resistance of chernozem and technical soil has been described. A significant positive relationship of the structure of chernozem in the two years of the research has been shown. Significant correlations between the data of different years in the technical soil were found to be mostly negative.

Lateral Tension-Induced Penetration of Particles into a Liposome

Directory of Open Access Journals (Sweden)

Kazuki Shigyou

2017-07-01

Full Text Available It is important that we understand the mechanism of the penetration of particles into a living cell to achieve advances in bionanotechnology, such as for treatment, visualization within a cell, and genetic modification. Although there have been many studies on the application of functional particles to cells, the basic mechanism of penetration across a biological membrane is still poorly understood. Here we used a model membrane system to demonstrate that lateral membrane tension drives particle penetration across a lipid bilayer. After the application of osmotic pressure, fully wrapped particles on a liposome surface were found to enter the liposome. We discuss the mechanism of the tension-induced penetration in terms of narrow constriction of the membrane at the neck part. The present findings are expected to provide insight into the application of particles to biological systems.

Antibody tumor penetration

Science.gov (United States)

Thurber, Greg M.; Schmidt, Michael M.; Wittrup, K. Dane

2009-01-01

Antibodies have proven to be effective agents in cancer imaging and therapy. One of the major challenges still facing the field is the heterogeneous distribution of these agents in tumors when administered systemically. Large regions of untargeted cells can therefore escape therapy and potentially select for more resistant cells. We present here a summary of theoretical and experimental approaches to analyze and improve antibody penetration in tumor tissue. PMID:18541331

TXRF versus conventional EDXRF using 150 nm AP1 sample support films

International Nuclear Information System (INIS)

Wobrauschek, P.; Buzanich, G.; Marosi, N.

2000-01-01

Total reflection x-ray fluorescence analysis (TXRF ) is a powerful analytical tool for trace element analysis in the ng/g concentration or pg absolute region for medium Z elements using commercial or own designed TXRF equipment. One of the goals of TXRF is the extreme small penetration depth of the primary radiation into the reflector - substrate of 3-4 run if an incidence angle of about 1 mrad is adjusted. Among others, this effect results in a drastically reduced background in the measured spectra. This is caused by the reduction of elastic and inelastic scattered primary radiation from the substrate. Since there are now thin film supports commercially available having a thickness of 150 nm it is interesting to compare experimental results using TXRF and sample support films in 45 o incident beam and 45 o fluorescence emission geometry. As this film is only about 50 times more in thickness than the penetration depth in a quartz reflector, tests were performed to compare the analytical results and detection limits achievable from the same samples analyzed in total reflection geometry on a quartz reflector and conventional EDRXS geometry on the AP1 film with a dimple in the center for easy placing of the droplet. A volume of 3-5 μl of a liquid sample were used in both cases, pipetted and vacuum dried to prepare the sample. A high power 3 kW Mo-anode X-ray tube was used, for TXRF the line focus and for the conventional geometry the point focus was chosen. As additional results measurements from the TRACOR TN 5000 spectrometer will be presented using an air cooled low power tube with Rh - anode in a compact commercially available unit. A comparison of the results will be given in terms of sensitivity and detection limits, and future aspects for improvements and applications will be discussed. (author)

Impact of 10% SF6 Gas Compared to 100% Air Tamponade in Descemet's Membrane Endothelial Keratoplasty.

Science.gov (United States)

Rickmann, Annekatrin; Szurman, Peter; Jung, Sacha; Boden, Karl Thomas; Wahl, Silke; Haus, Arno; Boden, Katrin; Januschowski, Kai

2018-04-01

To compare the clinical outcomes following Descemet's membrane endothelial keratoplasty (DMEK) with 100% air tamponade versus 10% sulfur hexafluoride (SF 6 ) tamponade. Retrospective analysis of 108 consecutive DMEK cases subdivided by anterior chamber tamponade with 54 eyes receiving 10% SF 6 and 54 eyes receiving 100% air injection. A post-hoc matched analysis revealed no statistically significant differences between the groups. The main outcome measurements were the complication rate, including intra- and postoperative complications and graft detachment rate requiring re-bubbling. Clinical outcome included best-corrected visual acuity (BCVA), endothelial cell count (ECC), and central corneal thickness (CCT) measured 1, 3, and 6 months after DMEK surgery. The graft detachment rate with consecutive re-bubbling was 18.5% in the air group and 22.2% in the SF 6 group (p = 0.2). Remaining small peripheral graft detachments with a clear cornea occurred more often in the 100% air group (air: 22.2%; 12/54, 6/12 inferior compared to SF 6 : 7.4%; 4/54, 2/4 inferior; p = 0.06). The primary graft failure rate was comparable between the two groups. No complete graft detachment occurred. Outcome results for BCVA, ECC, and CCT at all follow-up time points were comparable between the two groups. The clinical outcomes (including re-bubbling rate, primary graft failure rate, and endothelial cell loss) were comparable with 100% air versus 10% SF 6 tamponade, whereas other studies suggest that a higher SF 6 concentration (20%) may result in a lower re-bubbling rate.

The contemporary management of penetrating splenic injury.

Science.gov (United States)

Berg, Regan J; Inaba, Kenji; Okoye, Obi; Pasley, Jason; Teixeira, Pedro G; Esparza, Michael; Demetriades, Demetrios

2014-09-01

Selective non-operative management (NOM) is standard of care for clinically stable patients with blunt splenic trauma and expectant management approaches are increasingly utilised in penetrating abdominal trauma, including in the setting of solid organ injury. Despite this evolution of clinical practice, little is known about the safety and efficacy of NOM in penetrating splenic injury. Trauma registry and medical record review identified all consecutive patients presenting to LAC+USC Medical Center with penetrating splenic injury between January 2001 and December 2011. Associated injuries, incidence and nature of operative intervention, local and systemic complications and mortality were determined. During the study period, 225 patients experienced penetrating splenic trauma. The majority (187/225, 83%) underwent emergent laparotomy. Thirty-eight clinically stable patients underwent a deliberate trial of NOM and 24/38 (63%) were ultimately managed without laparotomy. Amongst patients failing NOM, 3/14 (21%) underwent splenectomy while an additional 6/14 (42%) had splenorrhaphy. Hollow viscus injury (HVI) occurred in 21% of all patients failing NOM. Forty percent of all NOM patients had diaphragmatic injury (DI). All patients undergoing delayed laparotomy for HVI or a splenic procedure presented symptomatically within 24h of the initial injury. No deaths occurred in patients undergoing NOM. Although the vast majority of penetrating splenic trauma requires urgent operative management, a group of patients does present without haemodynamic instability, peritonitis or radiologic evidence of hollow viscus injury. Management of these patients is complicated as over half may remain clinically stable and can avoid laparotomy, making them potential candidates for a trial of NOM. HVI is responsible for NOM failure in up to a fifth of these cases and typically presents within 24h of injury. Delayed laparotomy, within this limited time period, did not appear to increase

The Current Status of the Japanese Penetrator Mission: LUNAR-A

Science.gov (United States)

Tanaka, S.; Shiraishi, H.; Fujimura, A.; Hayakawa, H.

The scientific objective of the LUNAR-A, Japanese Penetrator Mission, is to explore the lunar interior by seismic and heat-flow experiments. Two penetrators containing two seismometers (horizontal and vertical components) and heat-flow probes will be deployed from a spacecraft onto the lunar surface, one on the nearside and the other on the farside of the moon. The final impact velocity of the penetrator will be about 300m/sec; it will encounter a shock of about 8000 G at impact on the lunar surface. According to numerous experimental impact tests using model penetrators and a lunar regolith analog target, each penetrator is predicted to penetrate to a depth of 1 to 3 m. The data obtained by the penetrators will be transmitted to the earth station via the LUNAR-A mother spacecraft orbiting at an altitude of about 200 km. The penetrator is a missile-shaped instrument carrier, which is about 14cm in diameter, 75cm in length, and about 14kg in weight without attitude control system. It contains a two-component seismometer and heat flow probes together with other supporting instruments such as a tilt meter and an accelerometer. The seismic observations are expected to provide key data on the size of the lunar core, as well as data on deep lunar mantle structure. The heat flow measurements at two penetrator deployment sites will also provide important data on the thermal structure and bulk concentrations of heat-generating elements in the Moon. These data will provide much stronger geophysical constraints on the origin and evolution of the Moon than has been obtained so far. The LUNAR-A spacecraft was supposed to be launched in the summer of 2004, but it was postponed due to the necessity of a replacement of the valves used in the RCS propulsion system of the spacecraft, following a recall issued by the manufacturer who found a malfunction of similar valves. Then, the technological review boards by ISAS and JAXA recommended that both the more robustness of the

Ink Penetration of Uncoated Inkjet Paper and Impact on Printing Quality

Directory of Open Access Journals (Sweden)

Ren'ai Li

2015-10-01

Full Text Available This study investigated ink penetration through imaging technology, first by gray and contour mapping and then calculating the ink penetration depth by programing. Next, a series of further analyses were carried out, including average ink permeability, ink distributions, and printability of different uncoated inkjet paper with different parameters. The impact on ink penetration of the microstructure and hydrophilicity of the uncoated paper was also studied. The experimental results indicated that paper specimens with sizing agent were resistant to the ink, resulting in a slow and shallow ink penetration. Paper containing filler had a more hydrophilic surface and porous structure, leading to a faster and deeper ink penetration. However, the calendering operation could make the paper structure more compact and reduce the porosity and penetration depth. When an appropriate combination of sizing agent, filler content, and the calendering process was utilized, a more stable hue could be produced with improvements in optical density, saturation, and color.

Barbs facilitate the helical penetration of honeybee (Apis mellifera ligustica stingers.

Directory of Open Access Journals (Sweden)

Jianing Wu

Full Text Available The stinger is a very small and efficient device that allows honeybees to perform two main physiological activities: repelling enemies and laying eggs for reproduction. In this study, we explored the specific characteristics of stinger penetration, where we focused on its movements and the effects of it microstructure. The stingers of Italian honeybees (Apis mellifera ligustica were grouped and fixed onto four types of cubic substrates, before pressing into different substrates. The morphological characteristics of the stinger cross-sections were analyzed before and after penetration by microscopy. Our findings suggest that the honeybee stinger undergoes helical and clockwise rotation during penetration. We also found that the helical penetration of the stinger is associated directly with the spiral distribution of the barbs, thereby confirming that stinger penetration involves an advanced microstructure rather than a simple needle-like apparatus. These results provide new insights into the mechanism of honeybee stinger penetration.

A state of the art on penetration failure estimation under external vessel cooling

International Nuclear Information System (INIS)

Min, B. T.; Park, R. J.; Kang, K. H.; Cho, Y. R.; Kim, J. W.; Kim, S. B.; Park, S. Y.; Lee, K. Y.

2000-04-01

A state of the art on penetration failure was reviewed and analyzed to establish the direction of the experimental program in the KNGR and to decide the test section design. The interaction between the corium and the reactor vessel and the corium behavior in the lower plenum of the reactor vessel were analyzed to investigate the penetration effect on severe accident progression, and the TMI-2 accident was investigated in the point of penetration failure. Theoretical model and experiment results on penetration failure under the severe accident were investigated and reviewed to establish the direction of the experimental program on the estimation of the penetration failure in the KNGR. These results were compared with the TMI-2 results. The existing test facilities on penetration failure were investigated and reviewed to decide the test section design. It can be said from the state of the art review that penetration in the lower plenum of the reactor vessel is a week point in the reactor vessel failure under the severe accident, but the reactor vessel may not be failed by penetration failure in condition with the coolant supply to the penetration. Since the penetration is different with reactor types and there is no study on estimation of the penetration welding, it is necessary to investigate failure or not of the penetration in condition with external vessel cooling to maintain the reactor vessel integrity in KNGR. In the present experimental program on the integrity estimation of the KNGR penetration, the aluminum oxide melt by thermite reaction and the test section with one penetration of the real size and real material were selected. The melt mass, the pressure of the system, and the vessel geometry were selected as an experimental parameter. (author)

Quantitative penetration testing with item response theory (extended version)

NARCIS (Netherlands)

Arnold, Florian; Pieters, Wolter; Stoelinga, Mariëlle Ida Antoinette

2013-01-01

Existing penetration testing approaches assess the vulnerability of a system by determining whether certain attack paths are possible in practice. Therefore, penetration testing has thus far been used as a qualitative research method. To enable quantitative approaches to security risk management,

Penetration and fusion of phospholipid vesicles by lysozyme

International Nuclear Information System (INIS)

Kim, J.; Kim, H.

1989-01-01

The lysozyme-induced fusion of phosphatidylserine/phosphatidylethanolamine vesicles as studied at a wide range of pH is found to correlate well with the binding of this protein to the vesicles. An identical 6000 molecular weight segment of lysozyme at the N-terminal region is found to be protected from tryptic digestion when initially incubated with vesicles at several pH values. Only this segment is labeled by dansyl chloride, which is partitioned into the bilayer. These results suggest the penetration of one segment of lysozyme into the bilayer. Photoactivated labeling of the membrane-penetrating segment of lysozyme with 3-(trifluoromethyl)-3-([ 125 I]iodophenyl)diazirine ([ 125 I]TID) and subsequent identification of the labeled residues by Edman degradation and gamma-ray counting indicate that four amino acids from the N-terminal are located outside the hydrophobic core of the bilayer. Although treatment of the membrane-embedded segment with aminopeptidase failed to cleave any amino acids from the N-terminal, it appears that a loop of lysozyme segment near the N-terminal penetrates into the bilayer at acidic pH. A helical wheel diagram shows that the labeling is done mainly on one surface of the alpha-helix. The penetration kinetics as studied by time-dependent [ 125 I]TID labeling coincide with the fusion kinetics, strongly suggesting that the penetration of the lysozyme segment into the vesicles is the cause of the fusion

Penetration and fusion of phospholipid vesicles by lysozyme

Energy Technology Data Exchange (ETDEWEB)

Kim, J.; Kim, H. (Korea Advanced Institute of Science and Technology, Seoul)

1989-10-01

The lysozyme-induced fusion of phosphatidylserine/phosphatidylethanolamine vesicles as studied at a wide range of pH is found to correlate well with the binding of this protein to the vesicles. An identical 6000 molecular weight segment of lysozyme at the N-terminal region is found to be protected from tryptic digestion when initially incubated with vesicles at several pH values. Only this segment is labeled by dansyl chloride, which is partitioned into the bilayer. These results suggest the penetration of one segment of lysozyme into the bilayer. Photoactivated labeling of the membrane-penetrating segment of lysozyme with 3-(trifluoromethyl)-3-(({sup 125}I)iodophenyl)diazirine (({sup 125}I)TID) and subsequent identification of the labeled residues by Edman degradation and gamma-ray counting indicate that four amino acids from the N-terminal are located outside the hydrophobic core of the bilayer. Although treatment of the membrane-embedded segment with aminopeptidase failed to cleave any amino acids from the N-terminal, it appears that a loop of lysozyme segment near the N-terminal penetrates into the bilayer at acidic pH. A helical wheel diagram shows that the labeling is done mainly on one surface of the alpha-helix. The penetration kinetics as studied by time-dependent ({sup 125}I)TID labeling coincide with the fusion kinetics, strongly suggesting that the penetration of the lysozyme segment into the vesicles is the cause of the fusion.

Effect of Drainage Conditions on Cone Penetration Testing in Silty Soils

DEFF Research Database (Denmark)

Poulsen, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

2011-01-01

This paper discusses the challenges that occur when performing Cone Penetration Tests (CPT) in silty soil due to changes in drainage conditions. In this paper, CPT results from various papers and researchers are collected and interpreted. Results from cone penetrations tests with various penetrat......This paper discusses the challenges that occur when performing Cone Penetration Tests (CPT) in silty soil due to changes in drainage conditions. In this paper, CPT results from various papers and researchers are collected and interpreted. Results from cone penetrations tests with various...

Effects of magnetic shear on current penetration in a tokamak

International Nuclear Information System (INIS)

Zhang Pengyun; Wang Long

2001-01-01

The penetrations of the parallel and perpendicular components of plasma currents are interrelated to each other due to the existence of magnetic shear in a tokamak configuration. Effects of the shear on the penetration of Fourier components of toroidal plasma current are analysed in a cylindrical column model. The current penetration is obviously strengthened by the shear for a bell-bike conductivity profile and low safety factor and low aspect ratio

Europa Kinetic Ice Penetrator (EKIP)

Data.gov (United States)

National Aeronautics and Space Administration — The goal of the proposed work is to validate an initial design for a Europa penetrator that can withstand the high g load associated with the expected hypervelocity...

In vitro penetration of bleaching agents into the pulp chamber

DEFF Research Database (Denmark)

Benetti, Ana Raquel; Valera, M C; Mancini, M N G

2004-01-01

To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures.......To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures....

Orientation dependence of deformation and penetration behavior of tungsten single crystal rods

International Nuclear Information System (INIS)

Bruchey, W.J. Jr.; Horwath, E.J.; Kingman, P.W.

1991-01-01

This paper reports on deformation and flow at a target/penetrator interface that occurs under conditions of high hydrostatic pressure and associated heat generation. To further elucidate the role of material structure in the penetration process, oriented single crystals of tungsten have been launched into steel targets and the residual penetrators recovered and analyzed. Both the penetration depth and the deformation characteristics were strongly influenced by the crystallographic orientation. Deformation modes for the left-angle 100 right-angle rod, which exhibited the best performance, appeared to involve considerable localized slip/cleavage and relatively less plastic working; the residual penetrator was extensively cracked and the eroded penetrator material was extruded in a smooth tube lined with an oriented array of discrete particle exhibiting cleavage fractures. Deformation appeared to be much less localized and to involve more extensive plastic working in the left-angle 011 right-angle rod, which exhibited the poorest penetration, while the left-angle 111 right-angle behaved in an intermediate fashion

Penetration of stimuli of fish skin for Acanthostomum brauni cercariae.

Science.gov (United States)

Ostrowski de Nuñez, M; Haas, W

1991-02-01

The cercaria of Acanthostomum brauni penetrates the skin of its fish host in response to a combination of two chemical signals from the fish skin surface: free fatty acids and a macro-molecular mucus component. The latter seems to be a protein, as the penetration-stimulating activity of fish skin surface mucus is eliminated by digestion with proteinase, but not by digestion with glycosidases, nor by a removal of glycosaminoglycans. These penetration-stimulating host signals differ from the glycoproteins that stimulate the attachment of A. brauni cercariae to the host and also from the macromolecular fish host signals which have been found to stimulate the attachment and penetration by Opisthorchis viverrini cercariae.

Impact of adult atopic dermatitis on topical drug penetration

DEFF Research Database (Denmark)

Garcia Ortiz, Patricia; Hansen, Steen H; Shah, Vinod P

2009-01-01

Appropriate methodologies for the determination of drug penetration in diseased skin have not yet been established. The aim of this study was to determine the cutaneous penetration of a metronidazole cream formulation in atopic dermatitis, employing dermal microdialysis and tape strip sampling...

Measurements of current penetration during PDX discharge start-up

International Nuclear Information System (INIS)

Meyerhofer, D.D.; Goldston, R.J.; Kaita, R.; Cavallo, A.; Grek, B.; Johnson, D.; McCune, D.C.; McGuire, K.; White, R.B.

1984-11-01

The current penetration phase of PDX discharges is examined. The Fast Ion Diagnostic Experiment has been used to measure the temporal evolution of the central q (r/a < 0.4), and to show the effect of magnetic perturbations on fast ions. During plasma current penetration, a series of magnetic perturbations was observed in the plasma. If the current was rising rapidly, the perturbations were accompanied by increases in β/sub theta/ + l/sub i//2 and decreases in the loop voltage, suggesting a rapid penetration of the plasma current. When the plasma current was rising slowly, a series of minor disruptions occurred. These were accompanied by decreases in β/sub theta/ + l/sub i//2 and the loop voltage, and increases in the plasma current. During this phase, current penetration may be enhanced by the change in the resistivity profile which accompanies the disruption

Endodontic sealers: Intratubular penetration and permeability to Enterococcus faecalis

Directory of Open Access Journals (Sweden)

Bortolini Maria Cecilia

2010-01-01

Full Text Available Aim : Evaluate in vitro the intratubular penetration and permeability of endodontic sealers in teeth contaminated with Enterococcus faecalis. Materials and Methods : Human canines were filled with AHPlus ® , Endo CPM-sealer ® or EndoRez ® sealers. To evaluate permeability, the coronary portion of each tooth was contaminated with E. faecalis, then the apical portion was immersed in brain heart infusion (BHI broth, and medium turbidity was observed for thirty days. Scanning electron microscope (SEM was used to evaluate the intratubular penetration of each sealer at the cervical, middle, and apical thirds of the tooth. Results : Only one tooth from the Endo CPM-sealer ® group presented broth contamination. EndoRez ® showed increased intratubular penetration compared to AHPlus ® and Endo CPM-sealer ® . Conclusions : Endo CPM-sealer ® showed greater permeability to E. faecalis and EndoRez ® showed increased intratubular penetration.

Penetrating spinal injuries and their management

Directory of Open Access Journals (Sweden)

A Kumar

2011-01-01

Full Text Available Penetrating spinal trauma due to missile/gunshot injuries has been well reported in the literature and has remained the domain of military warfare more often. Civic society′s recent upsurge in gunshot injuries has created a dilemma for the treating neurosurgeon in many ways as their management has always involved certain debatable and controversial issues. Both conservative and surgical management of penetrating spinal injuries (PSI have been practiced widely. The chief neurosurgical concern in these types of firearm injuries is the degree of damage sustained during the bullet traversing through the neural tissue and the after-effects of the same in long term. We had an interesting case of a penetrating bullet injury to cervical spine at C2 vertebral level. He was operated and the bullets were removed from posterior midline approach. Usually, the management of such cases differs from region to region depending on the preference of the surgeon but still certain common principles are followed world over. Thus, we realized the need to review the literature regarding spinal injuries with special emphasis on PSI and to study the recent guidelines for their treatment in light of our case.

Roentgenologic image of penetrating duodenal bulb ulcer

International Nuclear Information System (INIS)

Strunin, A.E.

1986-01-01

When studying a series of aimed roentgenograms in patients with peptic ulcer a gas bubble of irregular spherical configuration or two-layer niche were determined near the bulb medial contour. Gas bubble was from 0.5-0.7 to 3.5 cm in diameter. In such cases penetrating ulcers were determined in operations. Along with other signs gas bubble symptom, sometimes two-layer signs may be used for timely and exact roentgenological diagnosis of penetrating duodenal bulb ulcer in peptic ulcer disease

Study on penetration-induced initiation of energetic fragment

Science.gov (United States)

Qiao, Xiangxin; Xu, Heyang

2017-09-01

In order to investigate penetration-induced initiation of energetic fragment penetrating target, PTFE/Al (mass ratio 73.5/26.5) pressed and sintered into a Ф8mm × 8mm cylinder. To form energetic fragment, the cylinder was put into a closed container made by 35CrMnSiA. The container is 12mm long, 2mm thick. Energetic fragments were launched by a 14.5mm ballistic gun with a series of velocities and the penetrate process was simulated by AUTODYN-3D. The results show that the stress peak of energetic material exceed the initiation threshold, and energetic material will deflagrate, when energetic fragments impact velocity more than 800 m/s. The research results can provide reference for designs of energetic warhead.

A case of an intrahepatic fish bone penetration

International Nuclear Information System (INIS)

Tsuboi, Kazuhiko; Nakajima, Yoshiro; Yamamoto, Shunji; Nagao, Masatoshi; Nishimura, Kazumasa.

1981-01-01

A 56-year-old man was admitted to our hospital because of epigastric discomfort, appetite loss and body weight loss. A gallstone, signs of chronic inflammation and CEA-Z: 12.5 ng/ml were found. Abdominal CT scan revealed an intrahepatic low density nodule and an intra-and-extrahepatic high-dense, needle-like foreign body. By laparotomy a fish bone penetrating into the left lateral segment of the liver from the anterior wall of the prepyloric region of the stomach was found. Cholecystectomy was performed. The penetrating fish bone was withdrawn from the liver easily. The Postoperative course was smooth. The possibility of the definitive preoperative diagnosis of the intestinal fish bone penetration by abdominal CT scan was suggested. (author)

Interpretation of Cone Penetration Testing in Silty Soils Conducted under Partially Drained Conditions

DEFF Research Database (Denmark)

Holmsgaard, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

2016-01-01

The standard penetration rate used in cone penetration tests (CPTs) is 20 mm=s, regardless of soil type, which yields fully drained penetration in sand and fully undrained penetration in clay. However, for silty soils that represent an intermediate grain size composition and unique characteristic...

Microstructural observations on the terminal penetration of long rod projectile

OpenAIRE

Krushna Kumbhar; P. Ponguru Senthil; A.K. Gogia

2017-01-01

Present study focuses on the terminal penetration of tungsten heavy alloy (WHA) long rod penetrator impacted against armour steel at an impact velocity of 1600 m/s. The residual penetrator and armour steel target recovered after the ballistic test have been characterized using optical microscope, scanning electron microscope (SEM) and electron probe micro analyzer (EPMA). Metallurgical changes in target steel and WHA remnant have been analysed. Large shear stresses and shear localization have...

Two methodologies for physical penetration testing using social engineering

NARCIS (Netherlands)

Dimkov, T.; Pieters, Wolter; Hartel, Pieter H.

2009-01-01

During a penetration test on the physical security of an organization, if social engineering is used, the penetration tester directly interacts with the employees. These interactions are usually based on deception and if not done properly can upset the employees, violate their privacy or damage

Penetration of varnishes into demineralized root dentine in vitro

NARCIS (Netherlands)

Arends, J; Duschner, H; Ruben, JL

1997-01-01

In this paper the penetration of three different varnishes employed in caries prevention (Duraphat(R), Fluor Protector(R) and Cervitec(R)) into demineralized dentine is quantified using confocal laser scanning microscopy. The results show that the varnish penetration into lesions about 85 mu m in

High-pressure-induced water penetration into 3-isopropylmalate dehydrogenase

International Nuclear Information System (INIS)

Nagae, Takayuki; Kawamura, Takashi; Chavas, Leonard M. G.; Niwa, Ken; Hasegawa, Masashi; Kato, Chiaki; Watanabe, Nobuhisa

2012-01-01

Structures of 3-isopropylmalate dehydrogenase were determined at pressures ranging from 0.1 to 650 MPa. Comparison of these structures gives a detailed picture of the swelling of a cavity at the dimer interface and the generation of a new cleft on the molecular surface, which are accompanied by water penetration. Hydrostatic pressure induces structural changes in proteins, including denaturation, the mechanism of which has been attributed to water penetration into the protein interior. In this study, structures of 3-isopropylmalate dehydrogenase (IPMDH) from Shewanella oneidensis MR-1 were determined at about 2 Å resolution under pressures ranging from 0.1 to 650 MPa using a diamond anvil cell (DAC). Although most of the protein cavities are monotonically compressed as the pressure increases, the volume of one particular cavity at the dimer interface increases at pressures over 340 MPa. In parallel with this volume increase, water penetration into the cavity could be observed at pressures over 410 MPa. In addition, the generation of a new cleft on the molecular surface accompanied by water penetration could also be observed at pressures over 580 MPa. These water-penetration phenomena are considered to be initial steps in the pressure-denaturation process of IPMDH

A Study of Crystalline Mechanism of Penetration Sealer Materials

Directory of Open Access Journals (Sweden)

Li-Wei Teng

2014-01-01

Full Text Available It is quite common to dispense a topping material like crystalline penetration sealer materials (CPSM onto the surface of a plastic substance such as concrete to extend its service life span by surface protections from outside breakthrough. The CPSM can penetrate into the existing pores or possible cracks in such a way that it may form crystals to block the potential paths which provide breakthrough for any unknown materials. This study investigated the crystalline mechanism formed in the part of concrete penetrated by the CPSM. We analyzed the chemical composites, in order to identify the mechanism of CPSM and to evaluate the penetrated depth. As shown in the results, SEM observes the acicular-structured crystals filling capillary pores for mortar substrate of the internal microstructure beneath the concrete surface; meanwhile, XRD and FT-IR showed the main hydration products of CPSM to be C-S-H gel and CaCO3. Besides, MIP also shows CPSM with the ability to clog capillary pores of mortar substrate; thus, it reduces porosity, and appears to benefit in sealing pores or cracks. The depth of CPSM penetration capability indicated by TGA shows 0–10 mm of sealer layer beneath the concrete surface.

An integrated approach to fire penetration seal program management

International Nuclear Information System (INIS)

Rispoli, R.D.

1996-01-01

This paper discusses the utilization of a P.C. based program to facilitate the management of Entergy Operations Arkansas Nuclear One (ANO) fire barrier penetration seal program. The computer program was developed as part of a streamlining process to consolidate all aspects of the ANO Penetration Seal Program under one system. The program tracks historical information related to each seal such as maintenance activities, design modifications and evaluations. The program is integrated with approved penetration seal design details which have been substantiated by full scale fire tests. This control feature is intended to prevent the inadvertent utilization of an unacceptable penetration detail in a field application which may exceed the parameters tested. The system is also capable of controlling the scope of the periodic surveillance of penetration seals by randomly selecting the inspection population and generating associated inspection forms. Inputs to the data base are required throughout the modification and maintenance process to ensure configuration control and maintain accurate data base information. These inputs are verified and procedurally controlled by Fire Protection Engineering (FPE) personnel. The implementation of this system has resulted in significant cost savings and has minimized the allocation of resources necessary to ensure long term program viability

Use of Contact Lenses in Eyes with Severe Keratoconus: Long-term Results

Directory of Open Access Journals (Sweden)

Zerrin Tuncer

2012-05-01

Full Text Available Pur po se: To evaluate the long-term results of rigid gas permeable (RGP contact lenses in severe keratoconic eyes. Ma te ri al and Met hod: Severe keratoconic eyes with RGP contact lenses were evaluated retrospectively. Re sults: Long-term follow-up results of RGP contact lenses applied to 59 eyes of 42 patients (25 women, 17 men with a diagnosis of severe keratoconus were analyzed. Follow-up period was 3 to 12 years (mean: 6.57±3.60. The mean age at first exam was 25.88±9.10 years, the mean corneal curve K1 was 6.49±0.40 mm and K2 was 5.91±0.40 mm. Mean visual acuities with spectacles and contact lenses were 0.26±0.10 lines (0.63±0.20 logMAR and 0.66±0.20 lines (0.20±0.10 logMAR, respectively. The difference between both visual acuities was statistically significant (p=0.0001. At the last visit, the mean visual acuity with RGP contact lenses was 0.68±0.20 lines (0.19±0.10 logMAR. There was no statistically significant difference in visual acuity between first and last examinations with contact lenses (p=0.32. During the long-term follow-up period, apical scarring developed in 17 eyes. Only the 2 eyes of one patient needed penetrating keratoplasty after 6 years of RGP contact lens use. Dis cus si on: Use of RGP contact lenses should be considered before penetrating keratoplasty in cases of severe keratoconus. (Turk J Ophthalmol 2012; 42: 202-6

Study of the disorder by means of the superconducting penetration depth

International Nuclear Information System (INIS)

Arce, R.D.

1982-11-01

Measurements of the weak magnetic field penetration depth in the amorphous superconducting systems Lasub(1-x) Msub(x), being M = Cu, Al, Ga and Au, and in the Zr 70 Cu 30 system are presented. Measurements of the sample geometrical factors and the flux expulsion between the lowest temperature reached and the critical temperature, allows the determination of zero temperature penetration depth. The measurement of the flux expulsion as a function of temperature is used to determine the temperature dependence of penetration depth, used to evaluate the temperature dependence superconducting gap. The magnetization measurements have been made using an rf-SQUID. The evolution of the penetration depth with annealing is studied in the La 70 Cu 30 and Zr 70 Cu 30 systems. Measurements of the electrical resistivity and the critical temperature are used to verify the Gorkov equations in these materials. The variation of the penetration depth with annealing suggests that a metallurgical phase separation occurs within the submicrometer range. Penetration depth measurement is a tool to detect this type of phase separation in high kappa materials. (M.E.L.) [es

Market penetration of ethanol

International Nuclear Information System (INIS)

Szulczyk, Kenneth R.; McCarl, Bruce A.; Cornforth, Gerald

2010-01-01

This research examines in detail the technology and economics of substituting ethanol for gasoline. This endeavor examines three issues. First, the benefits of ethanol/gasoline blends are examined, and then the technical problems of large-scale implementation of ethanol. Second, ethanol production possibilities are examined in detail from a variety of feedstocks and technologies. The feedstocks are the starch/sugar crops and crop residues, while the technologies are corn wet mill, dry grind, and lignocellulosic fermentation. Examining in detail the production possibilities allows the researchers to identity the extent of technological change, production costs, byproducts, and GHG emissions. Finally, a U.S. agricultural model, FASOMGHG, is updated which predicts the market penetration of ethanol given technological progress, variety of technologies and feedstocks, market interactions, energy prices, and GHG prices. FASOMGHG has several interesting results. First, gasoline prices have a small expansionary impact on the U.S. ethanol industry. Both agricultural producers' income and cost both increase with higher energy prices. If wholesale gasoline is $4 per gallon, the predicted ethanol market penetration attains 53% of U.S. gasoline consumption in 2030. Second, the corn wet mill remains an important industry for ethanol production, because this industry also produces corn oil, which could be converted to biodiesel. Third, GHG prices expand the ethanol industry. However, the GHG price expands the corn wet mill, but has an ambiguous impact on lignocellulosic ethanol. Feedstocks for lignocellulosic fermentation can also be burned with coal to generate electricity. Both industries are quite GHG efficient. Finally, U.S. government subsidies on biofuels have an expansionary impact on ethanol production, but may only increase market penetration by an additional 1% in 2030, which is approximately 6 billion gallons. (author)

Review of Power System Stability with High Wind Power Penetration

DEFF Research Database (Denmark)

Hu, Rui; Hu, Weihao; Chen, Zhe

2015-01-01

analyzing methods and stability improvement approaches. With increasing wind power penetration, system balancing and the reduced inertia may cause a big threaten for stable operation of power systems. To mitigate or eliminate the wind impacts for high wind penetration systems, although the practical......This paper presents an overview of researches on power system stability with high wind power penetration including analyzing methods and improvement approaches. Power system stability issues can be classified diversely according to different considerations. Each classified issue has special...... and reliable choices currently are the strong outside connections or sufficient reserve capacity constructions, many novel theories and approaches are invented to investigate the stability issues, looking forward to an extra-high penetration or totally renewable resource based power systems. These analyzing...

Microstructural observations on the terminal penetration of long rod projectile

Directory of Open Access Journals (Sweden)

Krushna Kumbhar

2017-12-01

Full Text Available Present study focuses on the terminal penetration of tungsten heavy alloy (WHA long rod penetrator impacted against armour steel at an impact velocity of 1600 m/s. The residual penetrator and armour steel target recovered after the ballistic test have been characterized using optical microscope, scanning electron microscope (SEM and electron probe micro analyzer (EPMA. Metallurgical changes in target steel and WHA remnant have been analysed. Large shear stresses and shear localization have resulted in local failure and formation of erosion products. Severe plastic deformation acts as precursor for formation of adiabatic shear band (ASB induced cracks in target steel. Recovered WHA penetrator remnant also exhibits severe plastic deformation forming localized shear bands, ASB induced cracks and shock induced cracks.

Gastroscopic treatment of gastric band penetrating the gastric wall

DEFF Research Database (Denmark)

Jess, Per; Fonnest, G

1999-01-01

Gastric wall penetration of a gastric band after operation for morbid obesity is a well known late complication. The treatment is usually reoperation. In this case report we show that a band penetrating the gastric wall can be successfully treated by gastroscopic operation. This technique is more...

46 CFR 174.225 - Hull penetrations and shell connections.

Science.gov (United States)

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Hull penetrations and shell connections. 174.225 Section 174.225 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... § 174.225 Hull penetrations and shell connections. Each overboard discharge and shell connection except...

Penetrating abdominal injuries in adults seen at two teaching ...

African Journals Online (AJOL)

Objective: To determine the pattern and management outcome of penetrating abdominal injuries (PAI) in the two main teaching hospitals in Ghana. Study Design: A prospective ... Conclusion: Stab wounds are the main penetrating abdominal injuries seen mostly among young male adults in Ghana. Management was by a ...

Penetrating abdominal injury cases admitted in University of Benin ...

African Journals Online (AJOL)

The incidence of penetrating abdominal injuries especially through gunshot injuries is on the increase and is a major cause of morbidity and mortality in our community. Control measures and ways of reducing morbidity and mortality are suggested. Keywords: penetrating abdominal injuries, gun shot injuries. Annals of ...

Management of penetrating heart and accompanying lung injuries

International Nuclear Information System (INIS)

Ekim, H.; Basel, H.; Odabasi, D.; Tuncer, M.; Gumrukcuoglu, H.A.

2010-01-01

Objective: Penetrating heart injury is potentially a life threatening condition due to cardiac tamponade or exsanguinating hemorrhage. The aim of this study was to evaluate victims who were referred to our hospital with penetrating heart and accompanying lung injuries and to review our overall outcome with this type of combined injuries. Methodology: Twenty patients with combined penetrating heart and lung injuries were operated at Yuzuncu Yil University Research Hospital, between May 1999 and January 2010. The diagnosis of combined heart and lung injuries was proved by surgical exploration in all cases. The surgical procedures mainly included the relief of cardiac tamponade, control of bleeding, repair of cardiac and pulmonary lacerations, and coronary artery bypass grafting if required. Results: In this series of 20 patients; there were 18 males and two females between the age of 14 to 60 years, with a mean age of 34.8+-13.5 years. Seventeen victims sustained stab wounds, and the remaining three were injured by a gunshot wounds. In 20 patients there were 22 cardiac chamber injuries. The most commonly injured cardiac chamber was the right ventricle followed by the left ventricle. In addition to the injuries to heart muscle, injuries to the coronary arteries were found in two patients. The most commonly injured lung lobe was the left upper lobe. Conclusion: Our experience shows that early diagnosis and immediate surgical intervention are the main factors affecting patient survival after penetrating heart and lung injuries. Therefore, heart injury should always be kept in mind in victims with penetrating thoracic injuries. (author)

Penetration of ASM 981 in canine skin: a comparative study.

Science.gov (United States)

Gutzwiller, Meret E Ricklin; Reist, Martin; Persohn, Elke; Peel, John E; Roosje, Petra J

2006-01-01

ASM 981 has been developed for topical treatment of inflammatory skin diseases. It specifically inhibits the production and release of pro-inflammatory cytokines. We measured the skin penetration of ASM 981 in canine skin and compared penetration in living and frozen skin. To make penetration of ASM 981 visible in dog skin, tritium labelled ASM 981 was applied to a living dog and to defrosted skin of the same dog. Using qualitative autoradiography the radioactive molecules were detected in the lumen of the hair follicles until the infundibulum, around the superficial parts of the hair follicles and into a depth of the dermis of 200 to 500 microm. Activity could not be found in deeper parts of the hair follicles, the dermis or in the sebaceous glands. Penetration of ASM 981 is low in canine skin and is only equally spread in the upper third of the dermis 24 hours after application. Penetration in frozen skin takes even longer than in living canine skin but shows the same distribution.

Technology for a Thermo-chemical Ice Penetrator for Icy Moons

Science.gov (United States)

Arenberg, Jonathan; Harpole, George; Zamel, James; Sen, Bashwar; Lee, Greg; Ross, Floyd; Retherford, Kurt D.

2016-10-01

The ability to place sensors or to take samples below the ice surface enables a wide variety of potential scientific investigations. Penetrating an ice cap can be accomplished via a mechanical drill, laser drill, kinetic impactor, or heated penetrator. This poster reports on the development of technology for the latter most option, namely a self-heated probe driven by an exothermic chemical reaction: a Thermo-chemical ice penetrator (TChIP). Our penetrator design employs a eutectic mix of alkali metals that produce an exothermic reaction upon contact with an icy surface. This reaction increases once the ice starts melting, so no external power is required. This technology is inspired by a classified Cold-War era program developed at Northrop Grumman for the US Navy. Terrestrial demonstration of this technology took place in the Arctic; however, this device cannot be considered high TRL for application at the icy moons of the solar system due to the environmental differences between Earth's Arctic and the icy moons. These differences demand a TChIP design specific to these cold, low mass, airless worlds. It is expected that this model of TChIP performance will be complex, incorporating all of the forces on the penetrator, gravity, the thermo-chemistry at the interface between penetrator and ice, and multi-phase heat and mass transport, and hydrodynamics. Our initial efforts are aimed at the development of a validated set of tools and simulations to predict the performance of the penetrator for both the environment found on these icy moons and for a terrestrial environment. The purpose of the inclusion of the terrestrial environment is to aid in model validation. Once developed and validated, our models will allow us to design penetrators for a specific scientific application on a specific body. This poster discusses the range of scientific investigations that are enabled by TChIP. We also introduce the development plan to advance TChIP to the point where it can be

Demand side resource operation on the Irish power system with high wind power penetration

DEFF Research Database (Denmark)

Keane, A.; Tuohy, A.; Meibom, Peter

2011-01-01

part of the power system plant mix and contribute to the flexible operation of a power system. A model for demand side resources is proposed here that captures its key characteristics for commitment and dispatch calculations. The model is tested on the all island Irish power system, and the operation...... of the functions of conventional peaking plant. Demand side resources are also shown to be capable of improving the reliability of the system, with reserve capability identified as a key requirement in this respect....... of the model is simulated over one year in both a stochastic and deterministic mode, to illustrate the impact of wind and load uncertainty. The results illustrate that demand side resources can contribute to the efficient, flexible operation of systems with high penetrations of wind by replacing some...

Industrial Penetration and Internet Intensity

NARCIS (Netherlands)

C-L. Chang (Chia-Lin); M.J. McAleer (Michael); Y-C. Wu (Yu-Chieh)

2016-01-01

textabstractThis paper investigates the effect of industrial penetration and internet intensity for Taiwan manufacturing firms, and analyses whether the relationships are substitutes or complements. The sample observations are based on 153,081 manufacturing plants, and covers 26 two-digit industry

HMO penetration: has it hurt public hospitals?

Science.gov (United States)

Clement, J P; Grazier, K L

2001-01-01

The purpose of this study is to determine the extent to which health maintenance organization (HMO) penetration within the public hospitals' market area affects the financial performance and viability of these institutions, relative to private hospitals. Hospital- and market-specific measures are examined in a fully interacted model of over 2,300 hospitals in 321 metropolitan statistical areas (MSAs) in 1995. Although hospitals located in markets with higher HMO penetration have lower financial performance as reflected in revenues, expenses and operating margin, public hospitals are not more disadvantaged than other hospitals by managed care.

Flux penetration in a ferromagnetic/superconducting bilayer

Energy Technology Data Exchange (ETDEWEB)

Adamus, Z.; Cieplak, M.Z.; Abal' Oshev, A. [Polish Acad Sci, Inst Phys, PL-02668 Warsaw, (Poland); Konczykowski, M. [CEA/DSM/DRECAM, Laboratoire des Solides Irradies, F-91191 Gif Sur Yvette, (France); Konczykowski, M. [Ecole Polytech, CNRS - UMR 7642, F-91128 Palaiseau, (France); Cheng, X.M.; Zhu, L.Y.; Chien, C.L. [Johns Hopkins Univ, Dept Phys and Astron, Baltimore, MD 21218 (United States)

2007-07-01

An array of miniature Hall sensors is used to study the magnetic flux penetration in a ferromagnetic/superconducting bilayer consisting of Nb as a superconducting layer and Co/Pt multilayer with perpendicular magnetic anisotropy as a ferromagnetic layer, separated by an amorphous Si layer to avoid the proximity effect. It is found that the magnetic domains in the ferromagnetic layer create a large edge barrier in the superconducting layer which delays flux penetration. The smooth flux profiles observed in the absence of magnetic pinning change into terraced profiles in the presence of domains. (authors)

Towards Stochastic Optimization-Based Electric Vehicle Penetration in a Novel Archipelago Microgrid.

Science.gov (United States)

Yang, Qingyu; An, Dou; Yu, Wei; Tan, Zhengan; Yang, Xinyu

2016-06-17

Due to the advantage of avoiding upstream disturbance and voltage fluctuation from a power transmission system, Islanded Micro-Grids (IMG) have attracted much attention. In this paper, we first propose a novel self-sufficient Cyber-Physical System (CPS) supported by Internet of Things (IoT) techniques, namely "archipelago micro-grid (MG)", which integrates the power grid and sensor networks to make the grid operation effective and is comprised of multiple MGs while disconnected with the utility grid. The Electric Vehicles (EVs) are used to replace a portion of Conventional Vehicles (CVs) to reduce CO 2 emission and operation cost. Nonetheless, the intermittent nature and uncertainty of Renewable Energy Sources (RESs) remain a challenging issue in managing energy resources in the system. To address these issues, we formalize the optimal EV penetration problem as a two-stage Stochastic Optimal Penetration (SOP) model, which aims to minimize the emission and operation cost in the system. Uncertainties coming from RESs (e.g., wind, solar, and load demand) are considered in the stochastic model and random parameters to represent those uncertainties are captured by the Monte Carlo-based method. To enable the reasonable deployment of EVs in each MGs, we develop two scheduling schemes, namely Unlimited Coordinated Scheme (UCS) and Limited Coordinated Scheme (LCS), respectively. An extensive simulation study based on a modified 9 bus system with three MGs has been carried out to show the effectiveness of our proposed schemes. The evaluation data indicates that our proposed strategy can reduce both the environmental pollution created by CO 2 emissions and operation costs in UCS and LCS.

Generic penetration in the retail atypical antipsychotic market.

Science.gov (United States)

Lenderts, Susan; Kalali, Amir H; Buckley, Peter

2010-03-01

In this article, we explore the penetration of generic atypical antipsychotics in the United States market before and after the availability of generic risperidone in July 2008. Analysis suggests that, overall, generic penetration into the atypical antipsychotic market has grown from approximately three percent in January 2008 to more than 25 percent in December 2009. Similar trends are uncovered when branded and generic prescriptions are analyzed by specialty.

Penetration of charged particles through ordered isotropic matter

International Nuclear Information System (INIS)

Sigmund, P.

1977-01-01

A brief summary of some new results on fluctuation phenomena in particle penetration is presented. The results include collision statistics, positive and negative correlations and a framework for the treatment of cumulative effects in particle penetration. Incorporation of projectile and target states in the description and energy-loss straggling are discussed. Small-angle multiple scattering is considered and a comment made on ionic charge states. (B.R.H.)

Comparison of Sulfur Hexafluoride (SF6) and Air Tamponade in Noniridectomized Descemet Membrane Endothelial Keratoplasty.

Science.gov (United States)

Einan-Lifshitz, Adi; Sorkin, Nir; Boutin, Tanguy; Showail, Mahmood; Borovik, Armand; Jamshidi, Farzad; Chan, Clara C; Rootman, David S

2018-03-01

To compare the efficacy and safety of 20% sulfur hexafluoride gas (SF6) and air tamponade in patients who underwent noniridectomized Descemet membrane endothelial keratoplasty (DMEK). A retrospective chart review of patients who underwent DMEK with either air or SF6 tamponade: 41 eyes received air tamponade (group 1) and 41 received SF6 tamponade (group 2). Best spectacle-corrected visual acuity, endothelial cell density, and complications including graft detachment and elevated intraocular pressure were compared. The mean follow-up time was 8 ± 4 months in group 1 and 3 ± 2 months in group 2. Mean best spectacle-corrected visual acuity improved from 1.12 ± 0.88 to 0.64 ± 0.78 logarithm of the minimum angle of resolution (logMAR) in group 1 (P = 0.009) and from 1.00 ± 0.78 to 0.62 ± 0.53 logMAR in group 2 (P = 0.006). The graft detachment rate was 39% (16 eyes) in group 1 and 42% (17 eyes) in group 2 (P = 0.822). The rate of graft detachment larger than one third of the graft area was 17% in group 1 and 20% in group 2 (P = 0.775). Rebubbling was performed in 26.8% and 20% of eyes in group 1 and 2, respectively (P = 0.43). Average endothelial cell loss was 32% in group 1 and 33% in group 2 (P = 0.83). In the immediate postoperative period, elevated intraocular pressure was observed in 2 eyes (5%) in group 1 and in 4 eyes (10%) in group 2 (P = 0.4). There was 1 primary graft failure in each group. Use of air with it being readily available and short acting is a good method of Descemet membrane tamponade in noniridectomized DMEK.

Evaluation of nicotinamide microemulsion on the skin penetration enhancement.

Science.gov (United States)

Boonme, Prapaporn; Boonthongchuay, Chalida; Wongpoowarak, Wibul; Amnuaikit, Thanaporn

2016-01-01

This study purposed to evaluate a microemulsion containing nicotinamide for its characteristics, stability, and skin penetration and retention comparing with a solution of nicotinamide in 2:1 mixture of water and isopropyl alcohol (IPA). The microemulsion system was composed of 1:1 mixture of Span80 and Tween80 as a surfactant mixture, isopropyl palmitate (IPP) as an oil phase, and 2:1 mixture of water and IPA as an aqueous phase. Nicotinamide microemulsion was prepared by dissolving the active in the aqueous phase before simply mixing with the other components. It was determined for its characteristics and stability under various conditions. The skin penetration and retention studies of nicotinamide microemulsion and solution were performed by modified Franz diffusion cells, using newborn pig skin as the membrane. The results showed that nicotinamide microemulsion could be obtained as clear yellowish liquid, was water-in-oil (w/o) type, possessed Newtonian flow, and exhibited physicochemical stability when kept at 4 °C and room temperature (≈30 ± 2 °C) during 3 months. From the skin penetration data, the microemulsion could enhance the skin penetration of nicotinamide comparing with the solution. Additionally, nicotinamide microemulsion could provide much higher amount of skin retention than that of skin penetration, resulting in suitability for a cosmeceutical product.

Penetration of sub-micron aerosol droplets in composite cylindrical filtration elements

International Nuclear Information System (INIS)

Geurts, Bernard J.; Pratte, Pascal; Stolz, Steffen; Stabbert, Regina; Poux, Valerie; Nordlund, Markus; Winkelmann, Christoph

2011-01-01

Advection-diffusion transport of aerosol droplets in composite cylindrical filtration elements is analyzed and compared to experimental data. The penetration, characterizing the fraction of droplets that passes through the pores of a filtration element, is quantified for a range of flow rates. The advection-diffusion transport in a laminar Poiseuille flow is treated numerically for slender pores using a finite difference approach in cylindrical coordinates. The algebraic dependence of the penetration on the Peclet number as predicted theoretically, is confirmed by experimental findings at a variety of aspect ratios of the cylindrical pores. The effective penetration associated with a composite filtration element consisting of a set of parallel cylindrical pores is derived. The overall penetration of heterogeneous composite filtration elements shows an algebraic dependence to the fourth power on the radii of the individual pores that are contained. This gives rise to strong variations in the overall penetration in cases with uneven distributions of pore sizes, highly favoring filtration by the larger pores. The overall penetration is computed for a number of basic geometries, providing a point of reference for filtration design and experimental verification.

Deep penetration of light into biotissue

Science.gov (United States)

Bearden, Edward D.; Wilson, James D.; Zharov, Vladimir P.; Lowery, Curtis L.

2001-07-01

The results of a study of deep (several centimeters) light penetration into biological tissue are presented in order to estimate its significance to potentially photosensitive structures and processes including the fetal eyes. In order to accomplish this goal, samples of various tissues (fat, muscle, and uterus) from surgical patients and autopsies were examined with a double integrating sphere arrangement to determine their optical properties. The results were implemented in a Monte Carlo modeling program. Next, optical fiber probes were inserted into the uterus and abdominal wall of patients undergoing laparoscopic procedures. The fibers were couples to a photomultiplier tube with intervening filters allowing measurements of light penetration at various wavelengths. To determine the feasibility of stimulation in utero, a xenon lamp and waveguide were used to transilluminate the abdomen of several labor patients. Light in the range of 630 to 670 nm where the eye sensitivity and penetration depth are well matched, will likely provide the best chance of visual stimulation. Fetal heart rate, fetal movement, and fetal magnetoencephalography (SQUID) and electroencephalography (EEG) were observed in different studies to determine if stimulation has occurred. Since internal organs and the fetus are completely dark adapted, the amount of light required to simulate in our opinion could be on the order of 10(superscript -8 Watts.

Measuring penetration depth of electron beam welds. Final report