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Sample records for transumbilical laparoendoscopic single-site

  1. Transumbilical laparoendoscopic single-site donor nephrectomy: Without the use of a single port access device

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    Deepak Dubey

    2011-01-01

    Conclusions : Transumbilical LESS-DN can be cost-effectively performed using conventional laparoscopy instruments and without the need for a single port access device. Warm ischemia times with this technique are comparable with that during conventional multiport laparoscopic donor nephrectomy.

  2. Transumbilical laparoendoscopic single-site radical prostatectomy and cystectomy with the aid of a transurethral port: a feasibility study.

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    Su, Jian; Zhu, Qingyi; Yuan, Lin; Zhang, Yang; Zhang, Qingling; Wei, Yunfei

    2018-01-01

    To describe the surgical technique and report early outcomes of transurethral assisted laparoendoscopic single-site (LESS) radical prostatectomy (RP) and LESS radical cystectomy (RC) in a single institution. Between December 2014 and March 2016, a total of 114 LESS RPs and RCs were performed, comprising 68 LESS RPs, 38 LESS RCs with cutaneous ureterostomy (CU) and eight LESS RCs with orthotopic ileal neobladder (OIN). Access was achieved via a single-port, with four channels placed through a transumblical incision. After the apex of prostate was separated from the urethra, a self-developed port ('Zhu's port') was inserted through the urethra to facilitate resection of prostate and urethrovesical anastomosis. The peri-operative and postoperative data were collected and analysed retrospectively. Patients were followed up postoperatively for evidence of long-term side effects. All the procedures were completed successfully. No conversion to conventional laparoscopic surgery was necessary. For LESS RP, the average operating time was 152 min. Estimated blood loss was 117 mL. The mean hospital stay was 16.4 days after surgery. For LESS RC with CU and LESS RC with OIN, the mean operating times were 215 and 328 min, mean estimated blood loss was 175 and 252 mL, and mean hospital stay was 9.4 and 18.2 days, respectively. Six patients required blood transfusion (5.26%). Intra-operative complications occurred in two patients (1.75%), and postoperative complications in nine (7.89%). Fourteen out of 68 (20.6%) patients who underwent LESS RP had positive surgical margins. Follow-up ranged from 10 to 30.6 months. In the prostate cancer cases, good urinary control was observed in 35.3%, 97.1% and 100% of patients at 1, 6 and 12 months after the operation, respectively, while biochemical recurrence was observed in 11.8% patients. In the bladder cancer cases, two patients had local recurrence and two patients had distant metastasis. Our results showed that LESS RP and LESS RC

  3. Laparoendoscopic single site (LESS) cholecystectomy.

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    Hodgett, Steven E; Hernandez, Jonathan M; Morton, Connor A; Ross, Sharona B; Albrink, Michael; Rosemurgy, Alexander S

    2009-02-01

    The journey from conventional "open" operations to truly "minimally invasive" operations naturally includes progression from operations involving multiple trocars and multiple incisions to operations involving access through the umbilicus alone. Laparoscopic operations through the umbilicus alone, laparoendoscopic single site surgery (LESS), offer improved cosmesis and hopes for less pain and improved recovery. This study was undertaken to evaluate our initial experience with LESS cholecystectomy and to compare our initial experience to concurrent outcomes with more conventional multiport, multi-incision laparoscopic cholecystectomy. All patients referred for cholecystectomy over a 6-month period were offered LESS. Outcomes, including blood loss, operative time, complications, and length of stay were recorded. Outcomes with our first LESS cholecystectomies were compared to an uncontrolled group of concurrent patients undergoing multiport, multi-incision laparoscopic cholecystectomy at the same hospital by the same surgeon. Twenty-nine patients of median age 50 years undergoing LESS cholecystectomy from November 2007 until May 2008 were compared to 29* patients, median age 48 years, undergoing standard multiport, multiple-incision laparoscopic cholecystectomy over the same time period. Median operative time for patients undergoing LESS cholecystectomy was 72 min and was not different from that of patients undergoing multiport, multi-incision laparoscopic cholecystectomy (p = 0.81). Median length of hospital stay was 1.0 day for patients undergoing LESS cholecystectomy and was not different from patients undergoing standard laparoscopic cholecystectomy (p = 0.46). Operative estimated blood loss was less than 100 cc for all patients. No patients undergoing attempted LESS cholecystectomy had conversions to "open" operations; two patients had an additional trocar(s) placed distant from the umbilicus to aid in exposure. Three patients undergoing LESS cholecystectomy had

  4. Laparoendoscopic single site in pelvic surgery

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    Sanchez-Salas, Rafael; Clavijo, Rafael; Barret, Eric; Sotelo, Rene

    2012-01-01

    Laparoendoscopic single site (LESS) has recently gained momentum as feasible techniques for minimal access surgery. Our aim is to describe the current status of laparoendoscopic single site (LESS) in pelvic surgery. A comprehensive revision of the literature in LESS pelvic surgery was performed. References for this manuscript were obtained by performing a review of the available literature in PubMed from 01-01-01 to 30-11-11. References outside the search period were obtained selected manuscript΄s bibliography. Search terms included: pelvic anatomy, less in gynecology, single port colectomy, urological less, single port, single site, NOTES, LESS and single incision. 314 manuscripts were initially identified. Out of these, 46 manuscripts were selected based in their pelvic anatomy or surgical content; including experimental experience, clinical series and literature reviews. LESS drastically limit the surgeon's ability to perform in the operative field and the latter becomes hardened by the lack of space in anatomical location like the pelvis. Potential advantages of LESS are gained with the understanding that the surgical procedure is more technically challenging. Pelvic surgical procedures related to colorectal surgery, gynecology and urology have been performed with LESS technique and information available is mostly represented by case reports and short case series. Comparative series remain few. LESS pelvic surgery remain in its very beginning and due to the very specific anatomical conditions further development of LESS surgery in the mentioned area can be clearly be facilitated by using robotic technology. Standardization ad reproducibility of techniques are mandatory to further develop LESS in the surgical arena.. PMID:22557719

  5. Laparoendoscopic single site in pelvic surgery

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    Rafael Sanchez-Salas

    2012-01-01

    Full Text Available Laparoendoscopic single site (LESS has recently gained momentum as feasible techniques for minimal access surgery. Our aim is to describe the current status of laparoendoscopic single site (LESS in pelvic surgery. A comprehensive revision of the literature in LESS pelvic surgery was performed. References for this manuscript were obtained by performing a review of the available literature in PubMed from 01-01-01 to 30-11-11. References outside the search period were obtained selected manuscript΄s bibliography. Search terms included: pelvic anatomy, less in gynecology, single port colectomy, urological less, single port, single site, NOTES, LESS and single incision. 314 manuscripts were initially identified. Out of these, 46 manuscripts were selected based in their pelvic anatomy or surgical content; including experimental experience, clinical series and literature reviews. LESS drastically limit the surgeon′s ability to perform in the operative field and the latter becomes hardened by the lack of space in anatomical location like the pelvis. Potential advantages of LESS are gained with the understanding that the surgical procedure is more technically challenging. Pelvic surgical procedures related to colorectal surgery, gynecology and urology have been performed with LESS technique and information available is mostly represented by case reports and short case series. Comparative series remain few. LESS pelvic surgery remain in its very beginning and due to the very specific anatomical conditions further development of LESS surgery in the mentioned area can be clearly be facilitated by using robotic technology. Standardization ad reproducibility of techniques are mandatory to further develop LESS in the surgical arena..

  6. Laparoendoscopic single-site Heller myotomy with anterior fundoplication for achalasia.

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    Barry, Linda; Ross, Sharona; Dahal, Sujat; Morton, Connor; Okpaleke, Chinyere; Rosas, Melissa; Rosemurgy, Alexander S

    2011-06-01

    Laparoendoscopic single-site (LESS) surgery is beginning to include advanced laparoscopic operations such as Heller myotomy with anterior fundoplication. However, the efficacy of LESS Heller myotomy has not been established. This study aimed to evaluate the authors' initial experience with LESS Heller myotomy for achalasia. Transumbilical LESS Heller myotomy with concomitant anterior fundoplication for achalasia was undertaken for 66 patients after October 2007. Outcomes including operative time, complications, and length of hospital stay were recorded and compared with those for an earlier contiguous group of 66 consecutive patients undergoing conventional multi-incision laparoscopic Heller myotomy with anterior fundoplication. Symptoms before and after myotomy were scored by the patients using a Likert scale ranging from 0 (never/not severe) to 10 (always/very severe). Data were analyzed using the Mann-Whitney U test, the Wilcoxon matched-pairs test, and Fisher's exact test where appropriate. Patients undergoing LESS Heller myotomy were similar to those undergoing conventional laparoscopic Heller myotomy in gender, age, body mass index (BMI), blood loss, and length of hospital stay. However, the patients undergoing LESS Heller myotomies had operations of significantly longer duration (median, 117 vs. 93 min with the conventional laparoscopic approach) (pHeller myotomy, additional ports/incisions were required. No patients were converted to "open" operations, and no patients had procedure-specific complications. Symptom reduction was dramatic and satisfying after both LESS and conventional laparoscopic myotomy with fundoplication. The symptom reduction was similar with the two procedures. The LESS approach left no apparent umbilical scar. Heller myotomy with anterior fundoplication effectively treats achalasia. The findings showed LESS Heller myotomy with anterior fundoplication to be feasible, safe, and efficacious. Although the LESS approach increases operative

  7. Robotic laparoendoscopic single-site surgery: From present to future

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    Ayhan Verit

    2012-01-01

    Full Text Available The continued effort of improving cosmesis and reducing morbidity in urologic surgery has given rise to novel alternatives to traditional minimally invasive techniques: Laparoendoscopic Single-site Surgery (LESS and Natural Orifice Transluminal Endoscopic Surgery (NOTES. Despite the development of specialized access devices and instruments, the performance of complex procedures using LESS has been challenging due to loss of triangulation and instrument clashing. A robotic interface may represent the key factor in overcoming the critical restrictions related to NOTES and LESS. Although encouraging, current clinical evidence related to R-LESS remains limited as the current da Vinci® robotic platform has not been specifically designed for LESS. Robotic innovations are imminent and are likely to govern major changes to the current landscape of scarless surgery.

  8. Evolution of segmental anesthesia for Laparo-Endoscopic Single Site (LESS) cholecystectomy.

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    Ross, S B; Mangar, D; Karlnoski, R; Patel, R S; Camporesi, E M; Barry, L K; Luberice, K; Sprenker, C J; Rosemurgy, A S

    2012-06-01

    Transumbilical Laparo-Endoscopic Single Site (LESS) surgery promises improved cosmesis, quick recovery, reduced postoperative pain and shorter length of hospital stay. Since only a simple umbilical incision is used, LESS surgery can be completed with segmental epidural anesthesia. This study describes the evolution of our technique of LESS cholecystectomy from a combination of spinal and epidural anesthesia to thoracic epidural alone and presents our experience with its safety, the observed morbidity, and the reported patient satisfaction. In August 2009, a prospective evaluation of LESS cholecystectomy with regional anesthesia was undertaken. We recruited patients with chronic cholecystitis or symptomatic cholelithasis. Blood loss, operative time, complications, and length of hospital stay were measured. Preoperatively and 14 days postoperatively, outcome and symptom resolution were scored. Fifteen consecutive patients underwent LESS cholecystectomy; first with combined spinal-epidural (CSE), and then with thoracic epidural anesthesia alone. Immediate postoperative pain and discomfort were well tolerated. VAS scores upon admission to PACU were 0.4 (1.7±2.2). At postoperative day 14, the patients scored high values for "Satisfaction", 10 (10±1.0) and "Cosmesis", 10 (9.3±1.5). LESS cholecystectomy with epidural anesthesia can be undertaken safely. Patient satisfaction and cosmesis are particularly prominent amongst our patients. Our experience supports further utilization of epidural anesthesia for selected patients undergoing LESS cholecystectomy.

  9. Laparoendoscopic single site cholecystectomy: the first 100 patients.

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    Hernandez, Jonathan M; Morton, Connor A; Ross, Sharona; Albrink, Michael; Rosemurgy, Alexander S

    2009-08-01

    Laparoendoscopic single site (LESS) surgery promises improved cosmesis and possibly less pain. However, given the small series reported to date, true estimates of the advantages and possible disadvantages of LESS surgery remain unknown. This study was undertaken to evaluate the first 100 patients undergoing LESS cholecystectomy at our institution. Patients referred for cholecystectomy since November 2007 were considered for LESS cholecystectomy. Outcomes, including blood loss, operative time, complications, and length of stay, were recorded. Outcomes are compared with an uncontrolled concurrent group of patients undergoing multi-incision laparoscopic (i.e., conventional) cholecystectomy. One hundred patients with a median age of 44 years underwent LESS cholecystectomy; 30 patients with a median age of 46 years underwent conventional cholecystectomy over the same time period. Median operative time (70 vs 66 minutes, P = 0.67, Mann-Whitney) and hospital length of stay (1 vs 1 day, P = 0.81, Mann-Whitney) were not different for patients undergoing LESS or multi-incision cholecystectomies, respectively. Five patients undergoing LESS cholecystectomy had postoperative complications: cystic duct stump leak (one), pain control issues (three), and urinary retention (one). LESS cholecystectomy is a safe and effective alternative to conventional cholecystectomy. It can be undertaken without added operative time and provides patients with minimal, if any, scarring.

  10. Laparoendoscopic single site surgery in urology: A single centre experience

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    Arvind P Ganpule

    2012-01-01

    Full Text Available Objective : To analyze our experience of 87 cases with single port surgery, which is also known as laparoendoscopic single site surgery (LESS. Materials and Methods: Case records of all LESS procedures performed between December 2007 and June 2010 were analysed. The procedures performed were donor nephrectomy (n=45, simple nephrectomy (n=27, radical nephrectomy (n=5, pyeloplasty (n=9, and ureteroneocystostomy (n=1. Parameters analysed were operating room (OR time, estimated blood loss (EBL, visual analogue score (VAS, and complications in all patients undergoing LESS procedure and additionally, warm ischaemia time (WIT and graft outcome in patients undergoing LESS donor nephrectomy. In reconstructive procedures, the functional assessment was performed with a diuretic renogram at 6 months. Results: In LESS donor nephrectomy, the mean WIT was 6.9 ± 1.9 min. Mean serum creatinine in recipients at 1 month was 0.96 ± 0.21 mg%. We encountered one instance each of renal artery injury, renal vein injury, large bowel injury, minor cortical laceration at the upper pole and two instances of diaphragmatic injury. In LESS simple nephrectomy, the average OR time was 148.7 ± 52.2 min and hospital stay was 3.7 ± 1.2 days. There was one instance of large bowel injury during specimen retrieval. In LESS radical nephrectomy, the average OR time was 202.5 ± 35.7 min and average hospital stay was 4.2 ± 1.3 days. 6 patients of LESS pyeloplasty completed follow up with a diuretic renogram showing a good drainage. LESS ureteroneocystostomy could also be performed successfully without any complications. Conclusion: LESS surgery can be accomplished safely in nephrectomy and reconstructive procedures such as pyeloplasty and ureteroneocystostomy with equivalent outcomes as standard laparoscopy and with added benefits of cosmesis and quicker convalescence. LESS donor nephrectomy is a technically feasible procedure; current status of procedure needs to be proved with

  11. Learning curve for laparoendoscopic single-site surgery for an experienced laparoscopic surgeon

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    Pao-Ling Torng; Kuan-Hung Lin; Jing-Shiang Hwang; Hui-Shan Liu; I-Hui Chen; Chi-Ling Chen; Su-Cheng Huang

    2013-01-01

    Objectives: To assess the learning curve and safety of laparoendoscopic single-site (LESS) surgery of gynecological surgeries. Materials and methods: Sixty-three women who underwent LESS surgery by a single experienced laparoscopic surgeon from February 2011 to August 2011 were included. Commercialized single-incision laparoscopic surgery homemade ports were used, along with conventional straight instruments. The learning curve has been defined as the additional surgical time with respect ...

  12. Laparoendoscopic Single-Site Pyelolithotomy With Use of a Carter-Thomason Needle Grasper

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    Seo, Ill Young; Rim, Joung Sik

    2013-01-01

    Purpose To study the feasibility and safety of the procedure, we present our early experience with laparoendoscopic single-site (LESS) pyelolithotomy performed by use of a Carter-Thomason needle grasper. Materials and Methods Four patients underwent LESS pyelolithotomy for the removal of renal pelvic stones. The patients' mean age was 57.8 years, and their mean body mass index was 23.01. We used a homemade single-port device made with a surgical glove that was inserted into a 2.5-cm periumbil...

  13. Laparoendoscopic Single-Site Surgery (LESS for a Large Ovarian Tumour: First Clinical Case Report

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    Yao Dong Chua

    2011-01-01

    Main Outcome Measure(s. Conversion to standard laparoscopic technique or laparotomy, estimated blood loss, operative time , extent of scarring, occurrence of intra- and perioperative surgical complications, technical adequacy, and clinical outcome. Result(s. No conversion to standard laparoscopic technique or laparotomy, and no intraoperative or postoperative complications were observed. Total operative time was 99 minutes. The patient was discharged home on postoperative day one. Conclusion(s. Laparoendoscopic single-site bilateral salpingo-oophorectomy of a large ovarian tumour is feasible with standard laparoscopic instruments. It is safe and effective, with good results in terms of excellent cosmesis and minimal postoperative pain.

  14. Robot-Assisted Laparoendoscopic Single-Site Partial Nephrectomy With the Novel Da Vinci Single-Site Platform: Initial Experience

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    Komninos, Christos; Tuliao, Patrick; Kim, Dae Keun; Choi, Young Deuk; Chung, Byung Ha

    2014-01-01

    Purpose To report our initial clinical cases of robotic laparoendoscopic single-site (R-LESS) partial nephrectomy (PN) performed with the use of the novel Da Vinci R-LESS platform. Materials and Methods Three patients underwent R-LESS PN from November 2013 through February 2014. Perioperative and postoperative outcomes were collected and intraoperative difficulties were noted. Results Operative time and estimated blood loss volume ranged between 100 and 110 minutes and between 50 and 500 mL, respectively. None of the patients was transfused. All cases were completed with the off-clamp technique, whereas one case required conversion to the conventional (multiport) approach because of difficulty in creating the appropriate scope for safe tumor resection. No major postoperative complications occurred, and all tumors were resected in safe margins. Length of hospital stay ranged between 3 and 7 days. The lack of EndoWrist movements, the external collisions, and the bed assistant's limited working space were noticed to be the main drawbacks of this surgical method. Conclusions Our initial experience with R-LESS PN with the novel Da Vinci platform shows that even though the procedure is feasible, it should be applied in only appropriately selected patients. However, further improvement is needed to overcome the existing limitations. PMID:24955221

  15. Left Transperitoneal Adrenalectomy with a Laparoendoscopic Single-Site Surgery Combined Technique: Initial Case Reports

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    Yasuhiro Sumino

    2011-01-01

    Full Text Available Laparoendoscopic single-site surgery (LESS is a step toward the development of minimally invasive surgery. It is initially difficult for surgeons with limited experience to perform the surgery. We describe two cases of left adrenalectomy with a LESS combined with the addition of an accessory port. After a 2.5-cm skin incision was made at the level of the paraumbilicus to insert the primary 12-mm trocar for the laparoscope, a 5-mm nonbladed trocar was placed through the skin incision side-by-side with the primary trocar. A second 3-mm nonbladed trocar was then placed along the anterior axillary line; a multichannel trocar was not used as a single port. Both adrenalectomies were completed successfully. In patients with a minor adrenal tumor, a combined technique using LESS and an additional port is easier than LESS alone and may, therefore, be a bridge between the conventional laparoscopic approach and LESS.

  16. Laparoendoscopic single-site surgery in gynaecology: A new frontier in minimally invasive surgery

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    Fader Amanda

    2011-01-01

    Full Text Available Review Objective: To review the recent developments and published literature on laparoendoscopic single-site (LESS surgery in gynaecology. Recent Findings: Minimally invasive surgery has become a standard of care for the treatment of many benign and malignant gynaecological conditions. Recent advances in conventional laparoscopy and robotic-assisted surgery have favorably impacted the entire spectrum of gynaecological surgery. With the goal of improving morbidity and cosmesis, continued efforts towards refinement of laparoscopic techniques have lead to minimization of size and number of ports required for these procedures. LESS surgery is a recently proposed surgical term used to describe various techniques that aim at performing laparoscopic surgery through a single, small-skin incision concealed within the umbilicus. In the last 5 years, there has been a surge in the developments in surgical technology and techniques for LESS surgery, which have resulted in a significant increase in utilisation of LESS across many surgical subspecialties. Recently published outcomes data demonstrate feasibility, safety and reproducibility for LESS in gynaecology. The contemporary LESS literature, extent of gynaecological procedures utilising these techniques and limitations of current technology will be reviewed in this manuscript. Conclusions: LESS surgery represents the newest frontier in minimally invasive surgery. Comparative data and prospective trials are necessary in order to determine the clinical impact of LESS in treatment of gynaecological conditions.

  17. Is Laparoendoscopic Single-Site Adrenalectomy a Feasible Alternative in Treating Aldosterone-Producing Adenoma?

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    Che-Hsiung Wu

    2016-01-01

    Full Text Available Objective. To compare laparoendoscopic single-site (LESS and conventional multiport adrenalectomy in patients with aldosterone-producing adenoma (APA. Material and Methods. We retrospectively reviewed patients who had been clinically confirmed with unilateral APA and who underwent LESS or multiport adrenalectomy between 2009 and 2014. Perioperative data were obtained for all patients. Blood pressure and the levels of serum aldosterone, renin, and potassium were checked periodically. Results. We identified 45 APA patients in the LESS group and 71 in the multiport group. The baseline characteristics were matched between two groups. All adrenalectomies were completed successfully, except one with laparoscopic conversion in the single-port group and one open conversion in the multiport group. After a mean follow-up around one year, there were no significant group differences in the improvement of hypertension, number of types of medication taken, and cure of hypokalemia after operation. Conclusions. Our study confirm that LESS adrenalectomy achieved similar clinical and functional outcomes as conventional multiport adrenalectomy for management of unilateral APA.

  18. The learning curve of laparoendoscopic single-site (LESS) cholecystectomy: definable, short, and safe.

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    Hernandez, Jonathan; Ross, Sharona; Morton, Connor; McFarlin, Kellie; Dahal, Sujat; Golkar, Farhaad; Albrink, Michael; Rosemurgy, Alexander

    2010-11-01

    The applications of laparoendoscopic single-site (LESS) surgery, including cholecystectomy, are occurring quickly, although little is generally known about issues associated with the learning curve of this new technique including operative time, conversion rates, and safety. We prospectively followed all patients undergoing LESS cholecystectomy, and compared operations undertaken at our institutions in cohorts of 25 patients with respect to operative times, conversion rates, and complications. One-hundred fifty patients of mean age 46 years underwent LESS cholecystectomy. No significant differences in operative times were demonstrable between any of the 25-patient cohorts operated on at our institution. A significant reduction in operative times (p < 0.001) after completion of 75 LESS procedures was, however, identified with the experience of a single surgeon. No significant reduction in the number of procedures requiring an additional trocar(s) or conversion to open operations was observed after completion of 25 LESS cholecystectomies. Complication rates were low, and not significantly different between any 25-patient cohorts. For surgeons proficient with multi-incision laparoscopic cholecystectomy, the learning curve for LESS cholecystectomy begins near proficiency. Operative complications and conversions were infrequent and unchanged across successive 25-patient cohorts, and were similar to those reported for multi-incision laparoscopic cholecystectomy after the learning curve. Copyright © 2010 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  19. Defining the learning curve of laparoendoscopic single-site Heller myotomy.

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    Ross, Sharona B; Luberice, Kenneth; Kurian, Tony J; Paul, Harold; Rosemurgy, Alexander S

    2013-08-01

    Initial outcomes suggest laparoendoscopic single-site (LESS) Heller myotomy with anterior fundoplication provides safe, efficacious, and cosmetically superior outcomes relative to conventional laparoscopy. This study was undertaken to define the learning curve of LESS Heller myotomy with anterior fundoplication. One hundred patients underwent LESS Heller myotomy with anterior fundoplication. Symptom frequency and severity were scored using a Likert scale (0 = never/not bothersome to 10 = always/very bothersome). Symptom resolution, additional trocars, and complications were compared among patient quartiles. Median data are presented. Preoperative frequency/severity scores were: dysphagia = 10/8 and regurgitation = 8/7. Additional trocars were placed in 12 patients (10%), of whom all were in the first two quartiles. Esophagotomy/gastrotomy occurred in three patients. Postoperative complications occurred in 9 per cent. No conversions to "open" operations occurred. Length of stay was 1 day. Postoperative frequency/severity scores were: dysphagia = 2/0 and regurgitation = 0/0; scores were less than before myotomy (P Heller myotomy with anterior fundoplication well palliates symptoms of achalasia with no apparent scar. Placement of additional trocars only occurred early in the experience. For surgeons proficient with the conventional laparoscopic approach, the learning curve of LESS Heller myotomy with anterior fundoplication is short and safe, because proficiency is quickly attained.

  20. Compact teleoperated laparoendoscopic single-site robotic surgical system: Kinematics, control, and operation.

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    Isaac-Lowry, Oran Jacob; Okamoto, Steele; Pedram, Sahba Aghajani; Woo, Russell; Berkelman, Peter

    2017-12-01

    To date a variety of teleoperated surgical robotic systems have been developed to improve a surgeon's ability to perform demanding single-port procedures. However typical large systems are bulky, expensive, and afford limited angular motion, while smaller designs suffer complications arising from limited motion range, speed, and force generation. This work was to develop and validate a simple, compact, low cost single site teleoperated laparoendoscopic surgical robotic system, with demonstrated capability to carry out basic surgical procedures. This system builds upon previous work done at the University of Hawaii at Manoa and includes instrument and endoscope manipulators as well as compact articulated instruments designed to overcome single incision geometry complications. A robotic endoscope holder was used for the base, with an added support frame for teleoperated manipulators and instruments fabricated mostly from 3D printed parts. Kinematics and control methods were formulated for the novel manipulator configuration. Trajectory following results from an optical motion tracker and sample task performance results are presented. Results indicate that the system has successfully met the goal of basic surgical functionality while minimizing physical size, complexity, and cost. Copyright © 2017 John Wiley & Sons, Ltd.

  1. Quantifying the cognitive cost of laparo-endoscopic single-site surgeries: Gaze-based indices.

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    Di Stasi, Leandro L; Díaz-Piedra, Carolina; Ruiz-Rabelo, Juan Francisco; Rieiro, Héctor; Sanchez Carrion, Jose M; Catena, Andrés

    2017-11-01

    Despite the growing interest concerning the laparo-endoscopic single-site surgery (LESS) procedure, LESS presents multiple difficulties and challenges that are likely to increase the surgeon's cognitive cost, in terms of both cognitive load and performance. Nevertheless, there is currently no objective index capable of assessing the surgeon cognitive cost while performing LESS. We assessed if gaze-based indices might offer unique and unbiased measures to quantify LESS complexity and its cognitive cost. We expect that the assessment of surgeon's cognitive cost to improve patient safety by measuring fitness-for-duty and reducing surgeons overload. Using a wearable eye tracker device, we measured gaze entropy and velocity of surgical trainees and attending surgeons during two surgical procedures (LESS vs. multiport laparoscopy surgery [MPS]). None of the participants had previous experience with LESS. They performed two exercises with different complexity levels (Low: Pattern Cut vs. High: Peg Transfer). We also collected performance and subjective data. LESS caused higher cognitive demand than MPS, as indicated by increased gaze entropy in both surgical trainees and attending surgeons (exploration pattern became more random). Furthermore, gaze velocity was higher (exploration pattern became more rapid) for the LESS procedure independently of the surgeon's expertise. Perceived task complexity and laparoscopic accuracy confirmed gaze-based results. Gaze-based indices have great potential as objective and non-intrusive measures to assess surgeons' cognitive cost and fitness-for-duty. Furthermore, gaze-based indices might play a relevant role in defining future guidelines on surgeons' examinations to mark their achievements during the entire training (e.g. analyzing surgical learning curves). Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Laparoendoscopic single-site extraperitoneal inguinal hernia repair: initial experience in 10 patients.

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    Do, Minh; Liatsikos, Evangelos; Beatty, John; Haefner, Tim; Dunn, Ian; Kallidonis, Panagiotis; Stolzenburg, Jens-Uwe

    2011-06-01

    Recent technical advances and a trend toward laparoscopic single incision surgery have led us to explore the feasibility of laparoendoscopic single-site (LESS) hernia repair. We present our technique and initial experience with LESS extraperitoneal inguinal hernia repair in 10 consecutive men with unilateral inguinal hernias. Age range was 43.7 (28-64) years. Mean body mass index was 28 (range 24-30). Six were left inguinal hernias. There were six indirect and four direct hernias. Three patients had undergone previous open appendectomy. Incarcerated or bilateral hernias were excluded from our initial series. All cases were performed by three surgeons who were experienced in conventional totally extraperitoneal laparoscopic hernia repair as well as experienced in LESS. A literature review of current single-port inguinal hernia repair data is also presented. The mean operative time was 53 minutes (range 45-65  min). The average length of skin incision was 2.8  cm (range 2.3-3.2  cm). No drain was necessary in any of the patients, while no recordable bleeding was observed. There were no intraoperative or immediate postoperative complications. Hospitalization period was 2 days for all patients. After a limited follow-up of 1 month, there have been no recurrences and no complaints of testicular pain. The results of the current series compare favorably with those found in a literature review. LESS extraperitoneal inguinal hernia repair is both feasible and safe, although more technically demanding than its conventional laparoscopic counterpart. Although the cosmetic result with the former approach may prove superior, there are standing questions regarding the complications and long-term outcome. Randomized and if possible blinded trials that compare conventional and single-incision laparoscopic hernia repair may help to distinguish the most advantageous technique.

  3. Robotic-assisted laparoendoscopic single-site surgery (R-LESS) in urology: an evidence-based analysis.

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    Barret, E; Sanchez-Salas, R; Ercolani, M; Forgues, A; Rozet, F; Galiano, M; Cathelineau, X

    2011-06-01

    The objective of this manuscript is to provide an evidence-based analysis of the current status and future perspectives of robotic laparoendoscopic single-site surgery (R-LESS). A PubMed search has been performed for all relevant urological literature regarding natural orifice transluminal endoscopic surgery (NOTES) and laparoendoscopic single-site surgery (LESS). All clinical and investigative reports for robotic LESS and NOTES procedures in the urological literature have been considered. A significant number of clinical urological procedures have been successfully completed utilizing R-LESS procedures. The available experience is limited to referral centers, where the case volume is sufficient to help overcome the challenges and learning curve of LESS surgery. The robotic interface remains the best fit for LESS procedures but its mode of use continues to evolve in attempts to improve surgical technique. We stand today at the dawn of R-LESS surgery, but this approach may well become the standard of care in the near future. Further technological development is needed to allow widespread adoption of the technique.

  4. Current status of natural orifice trans-endoscopic surgery (NOTES and laparoendoscopic single site surgery (LESS in urologic surgery

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    Rafael E. Sanchez-Salas

    2010-08-01

    Full Text Available Laparoendoscopic single site surgery (LESS and natural orifice transluminal endoscopic surgery (NOTES represent novel approaches in urological surgery. To perform a review of the literature in order describe the current status of LESS and NOTES in Urology. References for this manuscript were obtained by performing a review of the available literature in PubMed from 01-01-02 to 15-05-09. Search terms included single port, single site, NOTES, LESS and single incision. A total of 412 manuscripts were initially identified. Out of these, 64 manuscripts were selected based in their urological content. The manuscript features subheadings for experimental and clinical studies, as NOTES-LESS is a new surgical technique and its future evolution will probably rely in initial verified feasibility. A subheading for reviews presents information regarding common language and consensus for the techniques. The issue of complications published in clinical series and the future needs of NOTES-LESS, are also presented.

  5. Laparoendoscopic single-site myomectomy and the use of fibrin sealant (Tisseel

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    Angelito Magno

    2015-11-01

    Full Text Available Myomectomy remains the standard surgical treatment for women with uterine myoma, who wish to preserve their fertility. However, it is often associated with increased blood loss and adhesion formation. Laparoscopic myomectomy has multiple advantages over open myomectomy1. A newer approach, laparoendoscopic single-site surgery, also known as LESS, has been developed and applied in gynecologic field.2 This is a case of a 41-year-old G2P1 patient, with the complaints of irregular menstrual cycles and lower abdominal pain for 6 months. Transvaginal ultrasound showed uterine myoma at the anterior corpus, measuring 6 × 5 cm2. The procedure is started by grasping the bilateral edges of the umbilicus with Allis forceps. A vertical incision, 1.5–2 cm, is made from the superficial skin of the umbilicus to the ventral peritoneum. A wound retractor of appropriate size is inserted and adjusted. A multiple instrument access port (LagisEndosurgical, Taichung, Taiwan is placed over the wound retractor (Figure 1. Prior to the procedure, inspection of the pelvic organs is performed to determine the pathology. Vasopressin is injected over the area of the myoma to decrease blood loss. Location of the myoma is then identified. Uterine incision is made on the serosa over the area of the myoma using the monopolar scissors. Using a bipolar instrument LigaSure®, ValleyLab, Inc., Boulder, Colorado, the incision is extended until the myoma is exposed. The myoma is grasped gently using the tenaculum forcep, and dissected bluntly along with it's pseudocapsule using the tip of suction irrigation gear. At the base of the myoma where feeding vessels may be located, coagulation by the advanced bipolar, is performed to prevent bleeding. The specimen is removed through the umbilicus. A sliding knot is made at the tail of one zero monofilament suture to fasten the anchor of the first knot. The uterus is then repaired with a continuous non-locking method. Hemostasis is

  6. Current status and future perspectives in laparoendoscopic single-site and natural orifice transluminal endoscopic urological surgery.

    Science.gov (United States)

    Autorino, Riccardo; Stein, Robert J; Lima, Estevão; Damiano, Rocco; Khanna, Rakesh; Haber, Georges-Pascal; White, Michael A; Kaouk, Jihad H

    2010-05-01

    Objective of this study is to provide an evidence-based analysis of the current status and future perspectives of scarless urological surgery. A PubMed search has been performed for all relevant urological literature regarding natural orifice transluminal endoscopic surgery (NOTES) and laparoendoscopic single-site surgery (LESS). In addition, experience with LESS and NOTES at our own institution has been considered. All clinical and investigative reports for LESS and NOTES procedures in the urological literature have been considered. A wide variety of clinical procedures in urology have been successfully completed by using LESS techniques. Thus far, experience with NOTES has largely been investigational, although early clinical reports are emerging. Further development of instrumentation and platforms is necessary for both techniques to become more widely adopted throughout the urological community.

  7. Comparison of different sets of instruments for laparoendoscopic single-site surgery in a surgical simulator with novices.

    Science.gov (United States)

    Wang, Dong; Shi, Long-Qing; Wang, Jing-Min; Jiang, Xiao-Hua; Ji, Zhen-Ling

    2016-04-01

    Given the parallel entry of working instruments through a single incision in laparoendoscopic single-site surgery, loss of triangulation in the abdominal cavity and counteracting movements of the instruments are inevitable obstacles. Some specially designed devices have emerged to ameliorate these challenges. Twenty-four novice participants were randomized into four groups using assigned instruments, conventional straight instruments, single-curved instruments, double-curved instruments and articulating instruments, respectively, to perform two basic tasks (peg transferring and pattern cutting) 14 times in a modified simulator. A test of the tasks and a resection of the intestine segment of a rat were performed. The task scores and evaluation of intraoperative skills during the resection of the intestine segment were recorded. The instrument of modified National Aeronautics and Space Administration Task Load Index (NASA-TLX) was completed. The task scores of the groups using single-curved instruments and articulating instruments were better than the other two groups on the simulator tasks, consistent with the evaluation of intraoperative skills during the resection of intestine segment. As the proficiency with the instruments increased, the task scores improved, as demonstrated by the learning curve. The workload measured by the modified NASA-TLX tool demonstrated that the groups using articulating instruments and double-curved instruments had a heavier workload in most of the categories compared with the other two groups. Single-curved and articulating instruments are more effective than conventional straight and double-curved devices, and are favourable in laparoendoscopic single-site surgery for novice learners. © 2013 Royal Australasian College of Surgeons.

  8. Laparoendoscopic Single-Site Surgery for the Treatment of Benign Adnexal Disease: A Prospective Trial

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    Anna Fagotti

    2010-01-01

    Full Text Available Background. To validate feasibility, efficacy, and safeness of laparoscopic treatment of benign adnexal diseases through a single transumbilical access (LESS in a prospective series of patients. Methods. A prospective clinical trial including 30 women has been conducted at the Division of Gynecology of Catholic University of Sacred Hearth of Rome. Patients underwent different laparoscopic procedures by LESS utilizing a multiport trocar and conventional straight laparoscopic instrumentation. Intra and perioperative outcome has been reported. Results. Ten mono/bilateral adnexectomies and 20 cystectomies have been performed by LESS approach. Laparoscopic procedures were completed through a single access in 28 cases (93.4%. No major intra- or postoperative complications were observed. Mean hospital stay was 1.3 days. Conclusions. LESS approach is feasible to treat benign adnexal disease with a very low conversion rate and no early or late complications. More clinical data are needed to confirm these advantages compared to standard laparoscopic technique.

  9. Robotic Laparoendoscopic Single-site Retroperitioneal Renal Surgery: Initial Investigation of a Purpose-built Single-port Surgical System.

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    Maurice, Matthew J; Ramirez, Daniel; Kaouk, Jihad H

    2017-04-01

    Robotic single-site retroperitoneal renal surgery has the potential to minimize the morbidity of standard transperitoneal and multiport approaches. Traditionally, technological limitations of non-purpose-built robotic platforms have hindered the application of this approach. To assess the feasibility of retroperitoneal renal surgery using a new purpose-built robotic single-port surgical system. This was a preclinical study using three male cadavers to assess the feasibility of the da Vinci SP1098 surgical system for robotic laparoendoscopic single-site (R-LESS) retroperitoneal renal surgery. We used the SP1098 to perform retroperitoneal R-LESS radical nephrectomy (n=1) and bilateral partial nephrectomy (n=4) on the anterior and posterior surfaces of the kidney. Improvements unique to this system include enhanced optics and intelligent instrument arm control. Access was obtained 2cm anterior and inferior to the tip of the 12th rib using a novel 2.5-cm robotic single-port system that accommodates three double-jointed articulating robotic instruments, an articulating camera, and an assistant port. The primary outcome was the technical feasibility of the procedures, as measured by the need for conversion to standard techniques, intraoperative complications, and operative times. All cases were completed without the need for conversion. There were no intraoperative complications. The operative time was 100min for radical nephrectomy, and the mean operative time was 91.8±18.5min for partial nephrectomy. Limitations include the preclinical model, the small sample size, and the lack of a control group. Single-site retroperitoneal renal surgery is feasible using the latest-generation SP1098 robotic platform. While the potential of the SP1098 appears promising, further study is needed for clinical evaluation of this investigational technology. In an experimental model, we used a new robotic system to successfully perform major surgery on the kidney through a single small

  10. Comparison between magnetic anchoring and guidance system camera-assisted laparoendoscopic single-site surgery nephrectomy and conventional laparoendoscopic single-site surgery nephrectomy in a porcine model: focus on ergonomics and workload profiles.

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    Han, Woong Kyu; Tan, Yung K; Olweny, Ephrem O; Yin, Gang; Liu, Zhuo-Wei; Faddegon, Stephen; Scott, Daniel J; Cadeddu, Jeffrey A

    2013-04-01

    To compare surgeon-assessed ergonomic and workload demands of magnetic anchoring and guidance system (MAGS) laparoendoscopic single-site surgery (LESS) nephrectomy with conventional LESS nephrectomy in a porcine model. Participants included two expert and five novice surgeons who each performed bilateral LESS nephrectomy in two nonsurvival animals using either the MAGS camera or conventional laparoscope. Task difficulty and workload demands of the surgeon and camera driver were assessed using the validated National Aeronautics and Space Administration Task Load Index (NASA-TLX) questionnaire. Surgeons were also asked to score 6 parameters on a Likert scale (range 1=low/easy to 5=high/hard): procedure-associated workload, ergonomics, technical challenge, visualization, accidental events, and instrument handling. Each step of the nephrectomy was also timed and instrument clashing was quantified. Scores for each parameter on the Likert scale were significantly lower for MAGS-LESS nephrectomy. Mean number of internal and external clashes were significantly lower for the MAGS camera (pNASA-TLX workload ratings by the surgeon and camera driver showed that MAGS resulted in a significantly lower workload than the conventional laparoscope during LESS nephrectomy (p<0.05). The use of the MAGS camera during LESS nephrectomy lowers the task workload for both the surgeon and camera driver when compared to conventional laparoscope use. Subjectively, it appears to also improve surgeons' impressions of ergonomics and technical challenge. Pending approval for clinical use, further evaluation in the clinical setting is warranted.

  11. Multicenter Experience with Nonischemic Multiport Laparoscopic and Laparoendoscopic Single-Site Partial Nephrectomy Utilizing Bipolar Radiofrequency Ablation Coagulator

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    Wassim M. Bazzi

    2011-01-01

    Full Text Available Objective. To investigate feasibility of multiport and laparoendoscopic single-site (LESS nonischemic laparoscopic partial nephrectomy (NI-LPN utilizing bipolar radiofrequency coagulator. Methods. Multicenter retrospective review of 60 patients (46 multiport/14 LESS undergoing NI-LPN between 4/2006 and 9/2009. Multiport and LESS NI-LPN utilized Habib 4X bipolar radiofrequency coagulator to form a hemostatic zone followed by nonischemic tumor excision and renorrhaphy. Demographics, tumor/perioperative characteristics, and outcomes were analyzed. Results. 59/60 (98.3% successfully underwent NI-LPN. Mean tumor size was 2.35 cm. Mean operative time was 160.0 minutes. Mean estimated blood loss was 131.4 mL. Preoperative/postoperative creatinine (mg/dL was 1.02/1.07 (=.471. All had negative margins. 12 (20% patients developed complications. 3 (5% developed urine leaks. No differences between multiport and LESS-PN were noted as regards demographics, tumor size, outcomes, and complications. Conclusion. Initial experience demonstrates that nonischemic multiport and LESS-PN is safe and efficacious, with excellent short-term preservation of renal function. Long-term data are needed to confirm oncological efficacy.

  12. [The LESS (Laparo-endoscopic Single-Site) procedure in urology. Technical and clinical aspects].

    Science.gov (United States)

    Neri, F; Cindolo, L; Gidaro, S; Schips, L

    2010-01-01

    Minimally invasive urology is rapidly advancing, and single-site laparoscopic surgery is being explored clinically. Such laparoscopic procedures are technically challenging and require an experienced laparoscopic surgeon due to the lack of port placement triangulation and instrument clashing. In the last years several surgeons all over the world have explored the feasibility and safety of LESS using several and different ports, approaches and devices. Hundreds of procedures have been described with overall favorable intraoperative and postoperative outcomes. Our experience consists of more than 30 procedures successfully completed for adrenal, kidney disease and varicocele. To date, LESS could be considered feasible and effective using currently available devices, however it is to be considered as an initial status technique requiring further confirmatory studies and advanced laparoscopic skills.

  13. Ovarian Suspension With Adjustable Sutures: An Easy and Helpful Technique for Facilitating Laparoendoscopic Single-Site Gynecologic Surgery.

    Science.gov (United States)

    Chen, Kuo-Hu; Chen, Li-Ru; Seow, Kok-Min

    2015-01-01

    To describe a method of ovarian suspension with adjustable sutures (OSAS) for facilitating laparoendoscopic single-site gynecologic surgery (LESS) and to investigate the effect of OSAS on LESS. Prospective cohort study (Canadian Task Force classification: II-2). University teaching hospital. One hundred seventy-eight patients with benign 5- to 15-cm cystic ovarian tumors who underwent LESS with OSAS (suspension group, n = 90) and without OSAS (control group, n = 88). For patients who underwent OSAS (suspension group), 1 end of double-head straight needles with a polypropylene suture was inserted into the pelvic cavity through the abdominal skin to penetrate the cyst or ovarian parenchyma and puncture outside the abdominal skin. After cutting off the needles, both sides of the remaining suture were held together by a clamp, without knotting, so that the manipulator could "lift," "loosen," or "fix" the stitches to adjust the tension. The average time to create OSAS was 2.9 min. For the suspension and control groups, the average blood loss was 81.4 and 131.8 mL (p < .001), and the operative time was 42.0 and 61.3 min (p < .001), respectively. There were no significant differences in the incidence of complications (5.6% vs 9.1%; p = .365), but there were significant differences in conversions to standard non-single-site laparoscopy (5.6% vs 15.9%; p = .025) and laparotomy (1.1% vs 6.8%; p = .040). Logistic regression analysis revealed that the ratios of conversion to standard non-single-site laparoscopy (odds ratio [OR], 0.126; 95% confidence interval [CI], 0.311-0.508) and laparotomy (OR, 0.032; 95% CI, 0.002-0.479) were much lower in the suspension group; the risk of complications was comparable (OR, 0.346; 95% CI, 0.085-1.403). OSAS is an easy, safe, and feasible method that offers advantages during LESS. Although routine use of OSAS is not necessary, OSAS can be considered during LESS to facilitate the surgery. Copyright © 2015 AAGL. Published by Elsevier Inc. All

  14. Laparoendoscopic single-site adrenalectomy versus conventional laparoscopic surgery: a systematic review and meta-analysis of observational studies.

    Science.gov (United States)

    Wang, Linhui; Wu, Zhenjie; Li, Mingmin; Cai, Chen; Liu, Bing; Yang, Qing; Sun, Yinghao

    2013-06-01

    To assess the surgical efficacy and potential advantages of laparoendoscopic single-site adrenalectomy (LESS-AD) compared with conventional laparoscopic adrenalectomy (CL-AD) based on published literature. An online systematic search in electronic databasesM including Pubmed, Embase, and the Cochrane Library, as well as manual bibliography searches were performed. All studies that compared LESS-AD with CL-AD were included. The outcome measures were the patient demographics, tumor size, blood loss, operative time, time to resumption of oral intake, hospital stay, postoperative pain, cosmesis satisfaction score, rates of complication, conversion, and transfusion. A meta-analysis of the results was conducted. A total of 443 patients were included: 171 patients in the LESS-AD group and 272 patients in the CL-AD group (nine studies). There was no significant difference between the two groups in any of the demographic parameters expect for lesion size (age: P=0.24; sex: P=0.35; body mass index: P=0.79; laterality: P=0.76; size: P=0.002). There was no significant difference in estimated blood loss, time to oral intake resumption, and length of stay between the two groups. The LESS-AD patients had a significantly lower postoperative visual analog pain score compared with the CL-AD group, but a longer operative time was noted. Both groups had a comparable cosmetic satisfaction score. The two groups had a comparable rate of complication, conversion, and transfusion. In early experience, LESS-AD appears to be a safe and feasible alternative to its conventional laparoscopic counterpart with decreased postoperative pain noted, albeit with a longer operative time. As a promising and emerging minimally invasive technique, however, the current evidence has not verified other potential advantages (ie, cosmesis, recovery time, convalescence, port-related complications, etc.) of LESS-AD.

  15. Minilaparoscopy-assisted transumbilical laparoscopic cholecystectomy

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    GERALDO JOSÉ DE SOUZA LIMA

    Full Text Available ABSTRACT The role of laparoscopy in the modern surgery era is well established. With the prospect of being able to improve the already privileged current situation, new alternatives have been proposed, such as natural orifice endoscopic surgery (NOTES, the method for single transumbilical access (LESS - Laparo-endoscopic single-site surgery and minilaparoscopy (MINI. The technique proposed by the authors uses a laparoscope with an operative channel like the flexible endoscope used in NOTES. All operative times are carried out through the umbilical trocar as in LESS, and assisted by a minilaparoscopy grasper. This new technic combines, and results from, the rationalization of technical particularities and synergy of these three approaches, seeking to join their advantages and minimize their disadvantages.

  16. Laparoendoscopic single-site repair of bladder rupture using a home-made single-port device: initial experience of treatment for a traumatic intraperitoneal bladder rupture.

    Science.gov (United States)

    Lee, Joo Yong; Kang, Dong Hyuk; Lee, Seung Wook

    2012-06-01

    We report our initial experience with a laparoendoscopic single-site (LESS) repair of a bladder rupture using a home-made single-port device. A 37-year-old man presented to the emergency department with complaints of voiding difficulty and gross hematuria after blunt trauma. Cystography and computed tomography revealed an intraperitoneal bladder rupture. The patient underwent LESS repair of a bladder rupture using the Alexis wound retractor, which was inserted through the umbilical incision. A home-made single-port device was made by fixing 6½ surgical gloves to the outer rim of the retractor and securing the glove finger to the end of 3 trocars with a tie. Using the flexible laparoscopic instruments and rigid instruments, LESS surgery was performed using a procedure similar to conventional laparoscopic surgery. The patient did not have any voiding problem after removal of the urethral Foley catheter on the 10th postoperative day. To our knowledge, this is the first published report of LESS repair of a traumatic bladder rupture using a home-made single-port device in the literature.

  17. Development of an in vivo visual robot system with a magnetic anchoring mechanism and a lens cleaning mechanism for laparoendoscopic single-site surgery (LESS).

    Science.gov (United States)

    Feng, Haibo; Dong, Dinghui; Ma, Tengfei; Zhuang, Jinlei; Fu, Yili; Lv, Yi; Li, Liyi

    2017-12-01

    Surgical robot systems which can significantly improve surgical procedures have been widely used in laparoendoscopic single-site surgery (LESS). For a relative complex surgical procedure, the development of an in vivo visual robot system for LESS can effectively improve the visualization for surgical robot systems. In this work, an in vivo visual robot system with a new mechanism for LESS was investigated. A finite element method (FEM) analysis was carried out to ensure the safety of the in vivo visual robot during the movement, which was the most important concern for surgical purposes. A master-slave control strategy was adopted, in which the control model was established by off-line experiments. The in vivo visual robot system was verified by using a phantom box. The experiment results show that the robot system can successfully realize the expected functionalities and meet the demands of LESS. The experiment results indicate that the in vivo visual robot with high manipulability has great potential in clinical application. Copyright © 2017 John Wiley & Sons, Ltd.

  18. Comparative Study of 2D and 3D Optical Imaging Systems: Laparoendoscopic Single-Site Surgery in an Ex Vivo Model.

    Science.gov (United States)

    Vilaça, Jaime; Pinto, José Pedro; Fernandes, Sandra; Costa, Patrício; Pinto, Jorge Correia; Leão, Pedro

    2017-12-01

    Usually laparoscopy is performed by means of a 2-dimensional (2D) image system and multiport approach. To overcome the lack of depth perception, new 3-dimensional (3D) systems are arising with the added advantage of providing stereoscopic vision. To further reduce surgery-related trauma, there are new minimally invasive surgical techniques being developed, such as LESS (laparoendoscopic single-site) surgery. The aim of this study was to compare 2D and 3D laparoscopic systems in LESS surgical procedures. All participants were selected from different levels of experience in laparoscopic surgery-10 novices, 7 intermediates, and 10 experts were included. None of the participants had had previous experience in LESS surgery. Participants were chosen randomly to begin their experience with either the 2D or 3D laparoscopic system. The exercise consisted of performing an ex vivo pork cholecystectomy through a SILS port with the assistance of a fixed distance laparoscope. Errors, time, and participants' preference were recorded. Statistical analysis of time and errors between groups was conducted with a Student's t test (using independent samples) and the Mann-Whitney test. In all 3 groups, the average time with the 2D system was significantly reduced after having used the 3D system ( P 3D system. This study suggests that the 3D system may improve the learning curve and that learning from the 3D system is transferable to the 2D environment. Additionally, the majority of participants prefer 3D equipment.

  19. Laparoendoscopic single site (LESS) in vivo suturing using a magnetic anchoring and guidance system (MAGS) camera in a porcine model: impact on ergonomics and workload.

    Science.gov (United States)

    Yin, Gang; Han, Woong Kyu; Faddegon, Stephen; Tan, Yung Khan; Liu, Zhuo-Wei; Olweny, Ephrem O; Scott, Daniel J; Cadeddu, Jeffrey A

    2013-01-01

    To compare the ergonomics and workload of the surgeon during single-site suturing while using the magnetic anchoring and guidance system (MAGS) camera vs a conventional laparoscope. Seven urologic surgeons were enrolled and divided into an expert group (n=2) and a novice group (n=5) according to their laparoendoscopic single-site (LESS) experience. Each surgeon performed 2 conventional LESS and 2 MAGS camera-assisted LESS vesicostomy closures in a porcine model. A Likert scale (scoring 1-5) questionnaire assessing workload, ergonomics, technical difficulty, visualization, and needle handling, as well as a validated National Aeronautics and Space Administration Task Load Index (NASA-TLX) questionnaire were used to evaluate the tasks and workloads. MAGS LESS suturing was universally favored by expert and novice surgeons compared with conventional LESS in workload (3.4 vs 4.2), ergonomics (3.4 vs 4.4), technical challenge (3.3 vs 4.3), visualization (2.4 vs 3.3), and needle handling (3.1 vs 3.9 respectively; PNASA-TLX assessments found MAGS LESS suturing significantly decreased the workload in physical demand (P=.004), temporal demand (P=.017), and effort (P=.006). External instrument clashing was significantly reduced in MAGS LESS suturing (P<.001). The total operative time of MAGS LESS suturing was comparable to that of conventional LESS (P=.89). MAGS camera technology significantly decreased surgeon workload and improved ergonomics. Nevertheless, LESS suturing and knot tying remains a challenging task that requires training, regardless of which camera is used. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Laparo-Endoscopic Single-Site Surgery for Radical and Cytoreductive Nephrectomy, Renal Vein Thrombectomy, and Partial Nephrectomy: A Prospective Pilot Evaluation

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    Ithaar H. Derweesh

    2010-01-01

    Full Text Available Introduction. Laparo-endoscopic single-site surgery (LESS may diminish morbidity of laparoscopic surgery. We prospectively evaluated feasibility and outcomes of LESS-Radical Nephrectomy (LESS-RN and Partial Nephrectomy (LESS-PN. Methods. 10 patients underwent LESS-RN (6 and LESS-PN (4 between 2/2009-5/2009. LESS-RN included 2 with renal vein thrombectomy, one of which was also cytoreductive. Transperitoneal LESS access was obtained by periumbilical incision. Patient/tumor characteristics, oncologic, and quality of life (QoL outcomes were analyzed. Results. 3 Men/7 Women (mean age 58.7 years, median follow-up 9.8 months underwent LESS. 9/10 cases were completed successfully. All had negative margins. Mean operative time was 161 minutes, estimated blood loss was 125 mL, and incision size was 4.4 cm. Median tumor size for LESS-RN and -PN was 5.0 and 1.7 cm (=.045. Median LESS-PN ischemia time was 24 minutes; mean preoperative/postoperative creatinine were 0.7/0.8 mg/dL (=.19. Mean pain score at discharge was 1.3. Mean preoperative, 3-, and 6-month postoperative SF-36 QoL Score was 73.8, 74.4 and 77.1 (=.222. All patients are currently alive. Conclusions. LESS-RN, renal vein thrombectomy, and PN are technically feasible and safe while maintaining adherence to oncologic principles, with excellent QoL preservation and low discharge pain scores. Further study is requisite.

  1. The Decline of Laparoendoscopic Single-Site Surgery: A Survey of the Endourological Society to Identify Shortcomings and Guidance for Future Directions.

    Science.gov (United States)

    Sorokin, Igor; Canvasser, Noah E; Irwin, Brian; Autorino, Riccardo; Liatsikos, Evangelos N; Cadeddu, Jeffrey A; Rane, Abhay

    2017-10-01

    To analyze the most recent temporal trends in the adoption of urologic laparoendoscopic single-site (LESS), to identify the perceived limitations associated with its decline, and to determine factors that might revive the role of LESS in the field of minimally invasive urologic surgery. A 15 question survey was created and sent to members of the Endourological Society in September 2016. Only members who performed LESS procedures in practice were asked to respond. In total, 106 urologists responded to the survey. Most of the respondents were from the United States (35%) and worked in an academic hospital (84.9%). Standard LESS was the most popular approach (78.1%), while 14.3% used robotics, and 7.6% used both. 2009 marked the most popular year to perform the initial (27.6%) and the majority (20%) of LESS procedures. The most common LESS procedure was a radical/simple nephrectomy (51%) followed by pyeloplasty (17.3%). In the past 12 months, 60% of respondents had performed no LESS procedures. Compared to conventional laparoscopy, respondents only believed cosmesis to be better, however, this enthusiasm waned over time. Worsening shifts in enthusiasm for LESS also occurred with patient desire, marketability, cost, safety, and robotic adaptability. The highest rated factor to help LESS regain popularity was a new robotic platform. The decline of LESS is apparent, with few urologists continuing to perform procedures attributed to multiple factors. The availability of a purpose-built robotic platform and better instrumentation might translate into a renewed future interest of LESS.

  2. Totally Transanal Laparo-Endoscopic Single-Site ProctoColectomy-Ileoanal J-Pouch (TLPC-J: An Experimental Study of a Novel Approach

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    Mohammad Reza Vahdad

    2015-09-01

    Full Text Available Background: The natural orifice transluminal endoscopic surgery (NOTES has become a commonly considered novel approach in the surgical field. The NOTES provide possibility of operation through the natural orifice and decreases the intentional puncture of the systemic organ and subsequent complications. Totally transanal laparo-endoscopic single-site proctoColectomy-Ileoanal J-Pouch (TLPC-J is a novel method in minimally invasive surgery for total colectomy. The main goal of this study is to perform this new method on an animal model, to assess probable complication and to resolve probable issues by using patients that are candidate for total colectomy. Method: Five dogs were prepared in lithotomy position. The TLPC-I procedure consists of endorectal technique with full thickness rectal dissection starting 1 cm orally from the dentate line above the peritoneal reflection and the proximal bowel was replaced into the abdominal cavity. Afterwards, the TriPort system was inserted in the anal canal and mesentrial resection of the total colon, mobilization of a distal ileal segment and intracorporeal suture of an ileal J-loop was accomplished by this system. An incision in the J-loop was conducted transanally. The J-pouch was created with an Endo-GIA® and sutured to the rectal wall. Results: All animals survived and passed stool with clear post operation situation. There was no infection in site of anastomosis. Conclusion: The TLPC-I provides the possibility of surgery without abdominal wall incision and decreases post operation complication such as pain, abdominal wound infection and wound dehiscence. This technique increases the quality of life and surgeons can discharge the patients early.

  3. Single-Incision Transumbilical Surgery (SITUS) versus Single-Port Laparoscopic Surgery and conventional laparoscopic surgery: a prospective randomized comparative study of performance with novices in a dry laboratory.

    Science.gov (United States)

    Schoenthaler, Martin; Avcil, Tuba; Sevcenco, Sabina; Nagele, Udo; Hermann, Thomas E W; Kuehhas, Franklin E; Shariat, Shahrokh F; Frankenschmidt, Alexander; Wetterauer, Ulrich; Miernik, Arkadiusz

    2015-01-01

    To evaluate the Single-Incision Transumbilical Surgery (SITUS) technique as compared to an established laparoendoscopic single-site surgery (LESS) technique (Single-Port Laparoscopic Surgery, SPLS) and conventional laparoscopy (CLS) in a surgical simulator model. Sixty-three medical students without previous laparoscopic experience were randomly assigned to one of the three groups (SITUS, SPLS and CLS). Subjects were asked to perform five standardized tasks of increasing difficulty adopted from the Fundamentals of Laparoscopic Surgery curriculum. Statistical evaluation included task completion times and accuracy. Overall performances of all tasks (except precision cutting) were significantly faster and of higher accuracy in the CLS and SITUS groups than in the SPLS group (p = 0.004 to p port-assisted LESS technique such as SPLS. The demonstrated advantages of SITUS may be attributed to a preservation of the basic principles of conventional laparoscopy, such as the use of straight instruments and an adequate degree of triangulation.

  4. Single site and conventional totally extraperitoneal techniques for uncomplicated inguinal hernia repair: A comparative study.

    Science.gov (United States)

    de Araújo, Felipe Brandão Corrêa; Starling, Eduardo Simão; Maricevich, Marco; Tobias-Machado, Marcos

    2014-10-01

    To demonstrate the feasibility of endoscopic extraperitoneal single site (EESS) inguinal hernia repair and compare it outcomes with the conventional totally extraperitoneal (TEP) technique. TEP inguinal hernia repair is a widely accepted alternative to conventional open technique with several perioperative advantages. Transumbilical laparoendoscopic singlesite surgery (LESS) is an emerging approach and has been reported for a number of surgical procedures with superior aesthetic results but other advantages need to be proven. Thirty-eight uncomplicated inguinal hernias were repaired by EESS approach between January 2010 and January 2011. All procedures were performed through a 25 cm infraumbilical incision using the Alexis wound retractor attached to a surgical glove and three trocars. Body mass index, age, operative time, blood loss, complications, conversion rate, analgesia requirement, hospital stay, return to normal activities and patient satisfaction with aesthetic results were analysed and compared with the last 38 matched-pair group of patients who underwent a conventional TEP inguinal hernia repair by the same surgeon. All procedures were performed successfully with no conversion. In both unilateral and bilateral EESS inguinal repairs, the mean operative time was longer than conventional TEP (55± 20 vs. 40± 15 min, P = 0.049 and 70± 15 vs. 55± 10 min, P = 0.014). Aesthetic result was superior in the EESS group (2.88± 0.43 vs. 2.79± 0.51, P = 0.042). There was no difference between the two approaches regarding blood loss, complications, hospital stay, time until returns to normal activities and analgesic requirement. EESS inguinal hernia repair is safe and effective, with superior cosmetic results in the treatment of uncomplicated inguinal hernias. Other advantages of this new technique still need to be proven.

  5. [Clinical retrospective control study of single-port laparoendoscopic and multi-port laparoscopic ovarian cystectomy].

    Science.gov (United States)

    Liu, X; Wen, M K; Liu, H Y; Sun, D W; Lang, J H; Fan, Q B; Shi, H H

    2017-10-25

    Objective: To investigate clinical outcomes of laparoendoscopic single-site ovarian cystectomy compared with traditional multi-port laparoscopic ovarian cystectomy. Methods: Data of 81 patients with ovarian cystectomy from January 2016 to May 2017, the single-site group ( n= 40) and the multi-port group ( n= 41) in Peking Union Medical College Hospital were retrospectively collected. The outcomes of single-site and multi-port groups were analyzed and compared, including: postoperative fever, operation time, blood loss, hemoglobin change, surgical complications, postoperative pain score, postoperative analgesic requirements, body image scale and cosmetic score, length of hospital stay, postoperative total cost. Results: No complication was found in two groups. No difference was found in postoperative fever, blood loss, hemoglobin change, postoperative pain score, length of hospital stay, and total cost between the two groups (all P> 0.05). Operation time was (50±20) minutes in single-site group, and (40±15) minutes in multi-port group; postoperative analgesic requirements was 28%(11/40) in single-site group, and 7%(4/41) in multi-port group; cosmetic score was 22.6±2.6 in single-site group, and 17.3±2.6 in multi-port group; body image scale was 5.7±1.2 in single-site group, and 6.2±1.2 in multi-port group; these four clinical parameters were statistical differences (all P< 0.05). Conculsion: Laparoendoscopic single-site ovarian cystectomy is feasible and safe, although it could't relieve the postoperative pian, it do offer a higher cosmetic satisfaction.

  6. The versatility of the transumbilical approach for laparotomy in infants

    African Journals Online (AJOL)

    cysts (n = 3), patent urachus (n = 3), postoperative complications of ... Keywords: abdominal masses, infants, laparotomy, transumbilical approach. Pediatric Surgery ... to the abdomen to facilitate the management of surgical pathologies other.

  7. Learning curve for laparoendoscopic single-site surgery for an experienced laparoscopic surgeon

    Directory of Open Access Journals (Sweden)

    Pao-Ling Torng

    2013-11-01

    Conclusion: LESS is a safe and feasible alternative to conventional laparoscopic surgery for adnexal and uterine diseases. A learning curve is not required for LESS surgery for experienced laparoscopic surgeons.

  8. Treatment of acute appendicitis with one-port transumbilical ...

    African Journals Online (AJOL)

    Background: Laparoscopic appendectomy is a feasible and safe alternative to open appendectomy for uncomplicated appendicitis. In the past decade several laparoscopic procedures have been described using one or more ports. We report our experience in treating acute appendicitis with one-port transumbilical ...

  9. Trans-umbilical Laparoscopic Appendectomy for Acute Appendicitis ...

    African Journals Online (AJOL)

    Trans-umbilical Laparoscopic Appendectomy for Acute Appendicitis without Raising Skin-flaps: An Easy-to-use Modification Applied to the Series of 164 Patients from a Rural Institute of Central India. Priyadarshan Anand Jategaonkar, Sudeep Pradeep Yadav1. INTRODUCTION. Laparoscopic appendectomy (LA) is widely ...

  10. Supra-transumbilical laparotomy (STL) approach for small bowel ...

    African Journals Online (AJOL)

    Background: Supra-Transumbilical Laparotomy (STL) has been used in paediatric surgery for a broad spectrum of abdominal procedures. We report our experience with STL approach for small bowel atresia repair in newborns and review previous published series on the topic. Patients and Methods: Fourteen patients with ...

  11. Transumbilical single-site laparoscopy takes the advantage of ultraminilaparotomy in managing an extremely large ovarian cyst

    Directory of Open Access Journals (Sweden)

    Hsuan Su

    2012-11-01

    Conclusion: This application not only provides both advantages of ultraminilaparotomy and laparoscopy but it also overcomes the limitations of both approaches. Therefore, it is the surgical approach of choice for a patient bearing an extremely large ovarian cystic tumor.

  12. Electrocautery device does not provide adequate pulmonary vessel sealing in transumbilical anatomic pulmonary lobectomy.

    Science.gov (United States)

    Liu, Hung-Ping; Chu, Yen; Wu, Yi-Cheng; Hsieh, Ming-Ju; Liu, Chieng-Ying; Chen, Tzu-Ping; Chao, Yin-Kai; Wu, Ching-Yang; Yeh, Chi-Ju; Ko, Po-Jen; Liu, Yun-Hen

    2016-05-01

    Safe pulmonary vessel sealing device plays a crucial role in anatomic lung resection. In 2014, we reported high rates of massive bleeding complications during transumbilical lobectomy in a canine model due to difficulty in managing the pulmonary vessel with an endostapler. In this animal survival series, we aimed to evaluate the outcome of pulmonary vessel sealing with an electrocautery device to simplify the transumbilical thoracic surgery. Under general anesthesia, a 3-cm longitudinal incision was made over the umbilicus. Under video guidance, a bronchoscope was inserted through the incision for exploration. The diaphragmatic wound was created with an electrocautery knife and used as the entrance into the thoracic cavity. Using the transumbilical technique, anatomic lobectomy was performed with electrosurgical devices and endoscopic vascular staplers in 15 canines. Transumbilical endoscopic anatomic lobectomy was successfully completed in 12 of the 15 animals. Intraoperative bleeding developed in three animals during pulmonary hilum dissection, where one animal was killed due to hemodynamic instability and the other two animals required thoracotomy to complete the operation. There were five delayed bleeding and surgical mortality cases caused by inadequate vessel sealing by electrosurgical devices. Postmortem examination confirmed correct transumbilical lobectomy in the twelve animals that survived the operations. Transumbilical anatomic lobectomy is technically feasible in a canine model; however, the electrosurgical devices were not effective in sealing the pulmonary vessel in the current canine model.

  13. Robotic single-site pelvic lymphadenectomy.

    Science.gov (United States)

    Tateo, Saverio; Nozza, Arrigo; Del Pezzo, Chiara; Mereu, Liliana

    2014-09-01

    To examine the feasibility of performing pelvic lymphadenectomy with robotic single site approach. Recent papers described the feasibility of robotic-single site hysterectomy [1-3] for benign and malign pathologies but only with the development of new single site 5mm instruments as the bipolar forceps, robotic single site platform can be safely utilized also for lymphadenectomy. A 65 year-old, multiparous patient with a body mass index of 22.5 and diagnosed with well differentiated adenocarcinoma of the endometrium underwent a robotic single-site peritoneal washing, total hysterectomy, bilateral adnexectomy and pelvic lymphadenectomy. The procedure was performed using the da Vinci Si Surgical System (Intuitive Surgical, Sunnyvale, CA) through a single 2,5 cm umbilical incision, with a multi-channel system and two single site robotic 5mm instruments. A 3-dimensional, HD 8.5mm endoscope and a 5mm accessory instrument were also utilized. Type I lymphonodes dissection for external iliac and obturator regions was performed [4]. Total operative time was 210 min; incision, trocar placement and docking time occurring in 12 min. Total console time was 183 min, estimated blood loss was 50 ml, no intra-operative or post-operative complications occurred. Hospital discharge occurred on post operative day 2 and total number of lymphnodes removed was 33. Difficulties in term of instrument's clashing and awkward motions have been encountered. Robotic single-site pelvic lymphadenectomy using bipolar forceps and monopolar hook is feasible. New developments are needed to improve surgical ergonomics and additional studies should be performed to explore possible benefits of this procedure. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Minimal invasive single-site surgery in colorectal procedures: Current state of the art

    Directory of Open Access Journals (Sweden)

    Diana Michele

    2011-01-01

    Full Text Available Background: Minimally invasive single-site (MISS surgery has recently been applied to colorectal surgery. We aimed to assess the current state of the art and the adequacy of preliminary oncological results. Methods: We performed a systematic review of the literature using Pubmed, Medline, SCOPUS and Web of Science databases. Keywords used were "Single Port" or "Single-Incision" or "LaparoEndoscopic Single Site" or "SILS™" and "Colon" or "Colorectal" and "Surgery". Results: Twenty-nine articles on colorectal MISS surgery have been published from July 2008 to July 2010, presenting data on 149 patients. One study reported analgesic requirement. The final incision length ranged from 2.5 to 8 cm. Only two studies reported fascial incision length. There were two port site hernias in a series of 13 patients (15.38%. Two "fully laparoscopic" MISS procedures with preparation and achievement of the anastomosis completely intracorporeally are reported. Future site of ileostomy was used as the sole access for the procedures in three studies. Lymph node harvesting, resection margins and length of specimen were sufficient in oncological cases. Conclusions: MISS colorectal surgery is a challenging procedure that seems to be safe and feasible, but the existing clinical evidence is limited. In selected cases, and especially when an ileostomy is planned, colorectal surgery may be an ideal indication for MISS surgery leading to a no-scar surgery. Despite preliminary oncological results showing the feasibility of MISS surgery, we want to stress the need to standardize the technique and carefully evaluate its application in oncosurgery under ethical committee control.

  15. Transumbilical Thoracoscopy Versus Conventional Thoracoscopy for Lung Wedge Resection: Safety and Efficacy in a Live Canine Model.

    Science.gov (United States)

    Chen, Tzu-Ping; Yen-Chu; Wu, Yi-Cheng; Yeh, Chi-Ju; Liu, Chien-Ying; Hsieh, Ming-Ju; Yuan, Hsu-Chia; Ko, Po-Jen; Liu, Yun-Hen

    2015-12-01

    Transumbilical single-port surgery has been associated with less postoperative pain and offers better cosmetic outcomes than conventional 3-port laparoscopic surgery. This study compares the safety and efficacy of transumbilical thoracoscopy and conventional thoracoscopy for lung wedge resection. The animals (n = 16) were randomly assigned to the transumbilical thoracoscopic approach group (n = 8) or conventional thoracoscopic approach group (n = 8). Transumbilical lung resection was performed via an umbilical incision and a diaphragmatic incision. In the conventional thoracoscopic group, lung resection was completed through a thoracic incision. For both procedures, we compared the surgical outcomes, for example, operating time and operative complications; physiologic parameters, for example, respiratory rate and body temperature; inflammatory parameters, for example, white blood cell count; and pulmonary parameters, for example, arterial blood gas levels. The animals were euthanized 2 weeks after the surgery for gross and histologic evaluations. The lung wedge resection was successfully performed in all animals. There was no significant difference in the mean operating times or complications between the transumbilical and the conventional thoracoscopic approach groups. With regard to the physiologic impact of the surgeries, the transumbilical approach was associated with significant elevations in body temperature on postoperative day 1, when compared with the standard thoracoscopic approach. This study suggests that both approaches for performing lung wedge resection were comparable in efficacy and postoperative complications. © The Author(s) 2014.

  16. Novel hybrid (magnet plus curve grasper) technique during transumbilical cholecystectomy: initial experience of a promising approach.

    Science.gov (United States)

    Millan, Carolina; Bignon, Horacion; Bellia, Gaston; Buela, Enrique; Rabinovich, Fernando; Albertal, Mariano; Martinez Ferro, Marcelo

    2013-10-01

    The use of magnets in transumbilical cholecystectomy (TUC) improves triangulation and achieves an optimal critical view. Nonetheless, the tendency of the magnets to collide hinders the process. In order to simplify the surgical technique, we developed a hybrid model with a single magnet and a curved grasper. All TUCs performed with a hybrid strategy in our pediatric population between September 2009 and July 2012 were retrospectively reviewed. Of 260 surgical procedures in which at least one magnet was used, 87 were TUCs. Of those, 62 were hybrid: 33 in adults and 29 in pediatric patients. The technique combines a magnet and a curved grasper. Through a transumbilical incision, we placed a 12-mm trocar and another flexible 5-mm trocar. The laparoscope with the working channel used the 12-mm trocar. The magnetic grasper was introduced to the abdominal cavity using the working channel to provide cephalic retraction of the gallbladder fundus. Across the flexible trocar, the assistant manipulated the curved grasper to mobilize the infundibulum. The surgeon operated through the working channel of the laparoscope. In this pediatric population, the mean age was 14 years (range, 4-17 years), and mean weight was 50 kg (range, 18-90 kg); 65% were girls. Mean operative time was 62 minutes. All procedures achieved a critical view of safety with no instrumental collision. There were no intraoperative or postoperative complications. The hospital stay was 1.4±0.6 days, and the median follow-up was 201 days. A hybrid technique, combining magnets and a curved grasper, simplifies transumbilical surgery. It seems feasible and safe for TUC and potentially reproducible.

  17. [Optimization of education for laparoendoscopic technologies in Ukraine].

    Science.gov (United States)

    Lesovoĭ, V N; Savenkov, V I; Tomin, M S

    2014-09-01

    International experience of training of surgeons, including urologists, in laparoendoscopic technologies, was analyzed. Practical course "The Fundamentals of aparoscopic Surgery" (FLS) and the European program of education for basic laparoscopic urologic skills (E-BLUS), which are used in specialized centers, constitute a standard programs of development of basic endosurgical skills. Such centers in Ukraine are absent. The project of complex system of a simulating education, testing and certification of surgeons, who are trained in endovideosurgical technologies, is proposed. While performing surveying of Ukrainian surgeons there were revealed the problems in a process of their education and introduction of highly technological methods: insufficient equipment with modern apparatuses, absence of a standardized pro- gram of education. The staged program of education was elaborated, taking into account progressive international experience and adopted to our environment and con ditions.

  18. A comparative study on trans-umbilical single-port laparoscopic approach versus conventional repair for incarcerated inguinal hernia in children

    OpenAIRE

    Jun, Zhang; Juntao, Ge; Shuli, Liu; Li, Long

    2016-01-01

    Purpose: The purpose of this study is to determine whether singleport laparoscopic repair (SLR) for incarcerated inguinal hernia in children is superior toconventional repair (CR) approaches. Method: Between March 2013 and September 2013, 126 infants and children treatedwere retrospectively reviewed. All the patients were divided into three groups. Group A (48 patients) underwent trans-umbilical SLR, group B (36 patients) was subjected to trans-umbilical conventional two-port laparoscopic rep...

  19. Colecistectomía endoscópica transumbilical: estudio preclínico de factibilidad en un modelo porcino Transumbilical endoscopic cholecystectomy: preclinical study of feasibility in a pig model

    Directory of Open Access Journals (Sweden)

    Rafael Torres Peña

    2010-06-01

    Full Text Available INTRODUCCIÓN. A partir del 2007 comenzó a popularizarse la cirugía endoscópica transumbilical, probablemente como consecuencia de los retos aún no resueltos que la cirugía endoscópica transluminal a través de orificios naturales ha debido enfrentar para su aplicación en la práctica clínica. Hasta la fecha se han descrito técnicas de cirugía endoscópica transumbilical con endoscopia flexible, con trocares multicanales, con varios trocares en una sola incisión, así como diferentes sistemas de retracción, tales como la retracción con suturas (técnicas de marionetas y la retracción magnética. El objetivo de esta investigación fue evaluar en un modelo porcino la factibilidad de una nueva técnica de colecistectomía endoscópica transumbilical. MÉTODOS. Se realizó un estudio prospectivo longitudinal en 6 cerdos con peso entre 22 y 26 kg. Se practicó la colecistectomía endoscópica transumbilical desde un puerto, con un solo canal de trabajo y con un nuevo sistema de retracción vesicular (TORCAM. La eutanasia de los animales se realizó de manera inmediata y fueron evaluadas las variables: factibilidad, calidad de exposición, efectos adversos del sistema de retracción, tiempo quirúrgico y examen macroscópico posoperatorio de la zona quirúrgica. RESULTADOS. La calidad de la retracción y exposición de la vesícula fue considerada óptima en todos los casos, lo que permitió la realización de la técnica quirúrgica en el 100 % de la muestra. No se reportaron complicaciones ni efectos adversos asociados al sistema de retracción vesicular. El tiempo quirúrgico promedio fue de 46 min. CONCLUSIONES. La colecistectomía endoscópica transumbilical propuesta es una nueva técnica que demostró ser factible en el modelo animal.INTRODUCTION. From 2007 transumbilical endoscopic surgery to become popular probably as a consequence of the not yet solved challenges that transluminal endoscopic surgery through natural orifices has

  20. Management of Gastropleural Fistula after Revisional Bariatric Surgery: A Hybrid Laparoendoscopic Approach.

    Science.gov (United States)

    Ghanem, Omar M; Abu Dayyeh, Barham K; Kellogg, Todd A

    2017-10-01

    Gastropleural fistula (GPF) is a serious complication after bariatric surgery. Multiple treatment modalities including pharmacologic, endoscopic, and revisional surgery have been proposed. We present a case of a GPF managed successfully with a laparoendoscopic approach utilizing a fistula plug. A 43-year-old male patient presented with a GPF after a revisional bariatric surgery. A laparoendoscopic approach including lysis of adhesions, identification of the fistula, plugging the fistula with a BioGore A® fistula plug, placement an enteric stent, placement of a feeding tube, and surgical drainage was performed. The multimedia video illustrates the technique used. Postoperatively, upper gastrointestinal (UGI) imaging showed no evidence of leak. The enteric stent was removed after 2 months after verifying complete healing of the fistula. A laparoendoscopic approach to GPF repair with the use of fistula plug is effective, safe, and feasible.

  1. Laparoendoscopic single-site surgery (LESS) for the treatment of different urologic pathologies in pediatrics: single-center single-surgeon experience.

    Science.gov (United States)

    Abdel-Karim, Aly M; Elmissery, Mostafa; Elsalmy, Salah; Moussa, Ahmed; Aboelfotoh, Ahmed

    2015-02-01

    Recently LESS has been reported as a valid minimally option for treatment of some urologic pathologies in pediatrics. However, the initial reports of pediatric LESS are still limited to case reports and initial case series. This may be due to the inherent technical difficulty of LESS and the currently available LESS instruments. In this report, we present the largest case series of pediatric LESS for treatment of different urologic pathologies in pediatrics. Included in this study are children who had LESS during the period of January 2011 to June 2013. Both Olympus TriPort (Olympus, New York, USA and Advance Surgical Concept, Wicklow, Ireland) and Covedien SILS access port (Covedien, Chicopec, Massachusetts, USA) were used and were inserted through the umbilicus. Exclusion criteria included children less than 3 years old, history of previous transperitoneal abdominal surgery, malignant indications, and complex urogenital congenital anomalies. All LESS procedures were done by a single experienced laparoscopist and data were reviewed retrospectively. Twenty-two children had 39 LESS procedures without conversion to conventional laparoscopy or open surgery. No intraoperative or postoperative complications were reported and no extra-port was added in any of the patients. The following table shows the mean age, operative time, hospital stay, VAS as well as the overall mean of different LESS procedures. In all patients the umbilical scar was invisible and all patients and their parents had high wound satisfaction. At a mean follow up of 18.6 ± 6.4 months, all patients with UPJO had successful repair. Our study included 13 boys with undescended testis who were managed in different ways according to the length of spermatic vessels and the size of the testis. One of the arguments against LESS management of undescended testis is that it requires a 2.5-cm incision, which is collectively larger than a 5-mm camera and two 3-mm working ports of conventional laparoscopy. However, the Triport access can be inserted through a 12-15-mm single umbilical incision without any additional openings in the abdomen as required with conventional laparoscopy which may increase the risk of internal organ injury and other port-related complications. Our results of five LESS varicocelectomies correlate with reports in the literature; regarding the operative time and hospital stay. LESS pediatric nephrectomy has been reported by many authors and our results correlates with that have been published. Compared with conventional laparoscopic nephrectomy, LESS nephrectomy seems to have shorter operative time and hospital stay. Although both cases of LESS nephrectomy were on the right side, we did not add any extra-ports which could be related to technical modifications during the surgery as well as the experience of the surgeon. To date, few data are available about LESS pyeloplasty in pediatrics. Our study included three patients who had left LESS pyeloplasties. In these patients, no extra-port was added. Despite of the technical difficulty of intracorporeal suturing during LESS, LESS pyeloplasty seems to be feasible with adequate training. Our patients had short hospital stay, low VAS at discharge, received a low dose of NSAID as postoperative analgesic and in all cases there was high wound satisfaction. One of the limitations of the current study could be the selection criteria of the patients, with children younger than 3 years and children who may be more technically difficult, being excluded. Furthermore, the number of patients in some indications is small and more patients are required to give solid conclusions and detect possible complications. Our study demonstrates the technical feasibility and safety of LESS for both ablative and reconstructive pathologies in pediatrics. However, more applications including a larger scale of pediatric patients as well as prospective comparative studies with conventional laparoscopy, are necessary. Copyright © 2014 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

  2. Single-port laparoscopic myomectomy using a new single-port transumbilical morcellation system: initial clinical study.

    Science.gov (United States)

    Kim, Yong-Wook; Park, Byung-Joon; Ro, Duck-Yeong; Kim, Tae-Eung

    2010-01-01

    To evaluate the feasibility of single-port laparoscopic myomectomy with transumbilical morcellation and suturing. Continuing prospective study (Canadian Task Force classification II-3). University hospital. Fifteen patients who underwent single-port laparoscopic myomectomy between September 2008 and October 2009 to remove single or multiple uterine myomas, at least 1 in each patient measuring greater than 4 cm in diameter. All single-port laparoscopic myomectomy procedures were performed by a single surgeon (Dr. Y.W. Kim). Myomas were extracted transumbilically by cutting the myomas into smaller pieces with a knife or a conventional electromechanical morcellator. After making a single 1.5- to 2.0-cm umbilical incision, the single-port system, created with a wound retractor and a surgical glove, was inserted. All operations were performed using conventional rigid straight laparoscopic instruments. Laparoscopic suturing was performed in intramural myomas and some subserosal myomas. Patient mean (SD; range) age was 38.3 (5.6; 29-49) years. The number of myomas per patient was 1.6 (1.4; 1-6). The diameter of the largest myomas was 6.1 (1.5; 4.2-9.6) cm. In 4 patients, only a knife was required for transumbilical extraction of myomas, and in 11 patients, transumbilical morcellation with an electromechanical morcellator with or without a knife was used. Transumbilical drainage tubes were inserted into the pelvic cavity in 11 of 15 patients. Operative time was 96.7 (33.8; 35-150) minutes. The decrease in postoperative hemoglobin concentration was 1.8 (1.2; 0.4-3.6) g/dL. During the operations, no patients required blood transfusion. No patients developed postoperative fever. Neither bowel injury nor urinary tract injury occurred in any patient. The postoperative hospital stay was 3.1 (0.8; 2-4) days. Single-port transumbilical morcellation using a conventional electromechanical morcellator with or without a knife is feasible. Single-port laparoscopic myomectomy is an

  3. Totally extraperitoneal (TEP) bilateral hernioplasty using the Single Site® robotic da Vinci platform (DV-SS TEP): description of the technique and preliminary results.

    Science.gov (United States)

    Cestari, A; Galli, A C; Sangalli, M N; Zanoni, M; Ferrari, M; Roviaro, G

    2017-06-01

    Laparoendoscopic single site totally extraperitoneal (TEP) hernia repair showed to be a feasible alternative to conventional laparoscopic hernia repair; nevertheless single site surgery, with the loss of instruments triangulation can be a demanding procedure. To overcome those hurdles, the Single Site® (SS) platform of the da Vinci (DV) Si robotic system enables to perform surgical procedures through a 25-mm skin incision, with a stable 3D vision and restoring an adequate triangulation of the surgical instruments. We present in details the technique and the preliminary results of DV-SS TEP, to our knowledge the first cases reported in literature. In March 2016, three consecutive male patients (mean age 46.6 years-mean BMI 25.3) with bilateral symptomatic inguinal hernia were submitted to DV-SS TEP in our institutions. Feasibility, codification of the technique, operative time and perioperative outcomes were recorded. All the procedures were completed as scheduled, with no conversion to other techniques. Mean operative time was 98.6 min, ranging between 155 and 55 min, reflecting the learning curve of the operating room team on this new procedure. No intraoperative or postoperative complications were experienced and all the patients were discharged within 24 h after surgery. Patients reported satisfactory postoperative course, with no recurrence of inguinal hernia and satisfaction in cosmetic result at 6-month follow-up. DV-SS TEP inguinal hernia repair showed to be feasible and effective surgical option for bilateral groin hernia repair. Patients' outcome was uneventful, with optimal cosmetic results. Further studies comparing this innovative technique to TEP or LESS TEP should be promoted.

  4. Transumbilical endoscopic surgery for incarcerated inguinal hernias in infants and children.

    Science.gov (United States)

    Zhou, Xuewu; Peng, Lei; Sha, Yongliang; Song, Daiqiang

    2014-01-01

    To describe transumbilical laparoscopic herniorrhaphy after unsuccessful attempted manual reduction of incarcerated inguinal hernias in infants and children. In our two hospitals, two-trocar transumbilical endoscopic surgery (TUES) is the standard technique used to repair incarcerated inguinal hernias in infants and children. Seventeen patients (aged 8months to 2.5years; median, 15months; 15 boys, 2 girls) with incarcerated inguinal hernias underwent urgent laparoscopy after unsuccessful attempted manual reduction. Two 3- or 5-mm trocars were inserted into the abdomen through two intraumbilical incisions, under laparoscopic guidance. The hernia was reduced by combined external manual pressure and internal pulling with bowel forceps. After inspection of the bowel, a round needle with a 2-0 nonabsorbable suture was introduced into the peritoneal cavity through the anterior abdominal wall near the internal inguinal ring. The hernial orifice was closed with an extraperitoneal purse-string suture around the internal inguinal ring, and tied with an intraperitoneal knot. A similar procedure was performed on the contralateral side if the processus vaginalis was patent. The TUES procedure was successful in all patients. No conversions to open surgery were required. The mean operating time was 30min (range, 25-40min). All patients were discharged on the second postoperative day. No complications such as postoperative bleeding, hydrocele, or scrotal edema were observed. The mean follow-up period was 15months. No cases of testicular atrophy, hypotrophy, or hernia recurrence were reported. Our preliminary experience with using TUES for the treatment of incarcerated inguinal hernias in infants and children had satisfactory outcomes. This technique appeared to be safe, effective, and reliable, and had excellent cosmetic results. Published by Elsevier Inc.

  5. Treatment of Duodenal Duplication by Trans-umbilical Exploratory Minimal Laparotomy

    Directory of Open Access Journals (Sweden)

    Li-Lan Chiang

    2009-08-01

    Full Text Available Duodenal duplication cysts are rare congenital lesions. Their presentation is often non-specific and physical examination and laboratory studies usually reveal no abnormal findings. The diagnosis of duodenal duplication cysts can thus be challenging and relies on ultrasonography, barium swallow, contrast enhanced computed tomography (CT, magnetic resonance imaging (MRI, and magnetic resonance cholangiopancreatography (MRCP. The management of duodenal duplication cyst is surgical. Laparotomy is usually necessary, and complete resection is the management goal. Subtotal excision with stripping of the mucosa due to close involvement of the pancreatobiliary tree, and endoscopic resection have Duodenal duplication cysts are rare congenital lesions usually diagnosed in infancy, although they may present in adulthood. Prenatal diagnosis is difficult, and postnatal diagnosis relies on ultrasonography, barium swallow, contrast-enhanced computerized tomography, magnetic resonance imaging (MRI, and magnetic resonance cholangiopancreatography. A female newborn was diagnosed with an abdominal cyst (size around 6 ×; 5 × 4 cm at gestational age (GA 24 weeks, by regular prenatal examination. After her birth at GA 37 weeks, we performed abdominal ultrasonography and MRI, but there was no definite diagnosis. The usual management of an abdominal cyst involves resection by laparotomy (requiring a large incision or laparoscopy (requiring several small incisions. We performed an exploratory trans-umbilical minimal laparotomy excision for surgery, and the pathology revealed duodenal duplication. In our case, there was no recurrence of the cyst after 18 months follow-up, and the operation scar was almost undetectable. Trans-umbilical minimal laparotomy excision may be considered as an alternative choice for the management of abdominal and duodenal duplication cysts.

  6. Laparoendoscopic pfannenstiel nephrectomy using conventional laparoscopic instruments - preliminary experience

    Directory of Open Access Journals (Sweden)

    Anibal W. Branco

    2010-12-01

    Full Text Available PURPOSE: To confirm the feasibility of the laparoendoscopic Pfannenstiel nephrectomy using conventional laparoscopic instruments. MATERIALS AND METHODS: Since March 2009, laparoscopic nephrectomy through a Pfannenstiel incision has been performed in selected patients in our service. The Veress needle was placed through the umbilicus which allowed carbon dioxide inflow. One 5 mm (or 10 mm trocar was placed at the umbilicus for the laparoscope, to guide the placement of three trocars over the Pfannenstiel incision. Additional trocars were placed as follows: a 10 mm in the midline, a 10 mm ipsilateral to the kidney to be removed (2 cm away from the middle one, and a 5 mm contralateral to the kidney to be removed (2 cm away from the middle one. The entire procedure was performed using conventional laparoscopic instruments. At the end of the surgery, trocars were removed and all three incisions were united into a single Pfannenstiel incision for specimen retrieval. RESULTS: Five nephrectomies were performed following this technique: one atrophic kidney, one kidney donation, two renal cancers and one bilateral renal atrophy. Median operative time was 100 minutes and median intraoperative blood loss was 100 cc. No intraoperative complications occurred and no patients required blood transfusion. Median length of hospital stay was 1 day (range 1 to 2 days. CONCLUSIONS: The use of the Pfannenstiel incision for laparoscopic nephrectomy seems to be feasible even when using conventional laparoscopic instruments, and can be considered a potential alternative for traditional laparoscopic nephrectomy.

  7. Trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife: a pilot animal study.

    Science.gov (United States)

    Jiang, Sheng-Jun; Shi, Hong; Swar, Gyanendra; Wang, Hai-Xia; Liu, Xiao-Jing; Wang, Yong-Guang

    2013-10-28

    To investigate the feasibility and safety of Natural orifice trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife in a non-survival porcine model. Pure natural orifice transluminal endoscopic surgery (NOTES) cholecystectomy was performed on three non-survival pigs, by transumbilical approach, using a water-jet hybrid-knife. Under general anesthesia, the following steps detailed the procedure: (1) incision of the umbilicus followed by the passage of a double-channel flexible endoscope through an overtube into the peritoneal cavity; (2) establishment of pneumoperitoneum; (3) abdominal exploration; (4) endoscopic cholecystectomy: dissection of the gallbladder performed using water jet equipment, ligation of the cystic artery and duct conducted using nylon loops; and (5) necropsy with macroscopic evaluation. Transumbilical endoscopic cholecystectomy was successfully completed in the first and third pig, with minor bleedings. The dissection times were 137 and 42 min, respectively. The total operation times were 167 and 69 min, respectively. And the lengths of resected specimen were 6.5 and 6.1 cm, respectively. Instillation of the fluid into the gallbladder bed produced edematous, distended tissue making separation safe and easy. Reliable ligation using double nylon loops insured the safety of cutting between the loops. There were no intraoperative complications or hemodynamic instability. Uncontrolled introperative bleeding occurred in the second case, leading to the operation failure. Pure NOTES trans-umbilical cholecystectomy with a water-jet hybrid-knife appears to be feasible and safe. Further investigation of this technique with long-term follow-up in animals is needed to confirm the preliminary observation.

  8. Abordaje transumbilical en pacientes pediátricos con sospecha de apendicitis aguda. Un serie de 424 pacientes

    Directory of Open Access Journals (Sweden)

    Luis Augusto Zárate Suárez

    2013-05-01

    Full Text Available Antecedentes: El tratamiento de la apendicitis aguda implica su extirpación; es frecuente la solicitud de cicatrices postquirúrgicas del mejor tamaño posible. Una de las estrategias disponibles es el abordaje transumbilical. Objetivos: Descubrir las características clínicas y los desenlaces operatorios de los pacientes pediátricos en quienes se realiza apendicectomía vía transumbilical. Metodología: Estudio prospectivo de 424 pacientes sucesivos en cuanto a los desenlaces operatorios a corto plazo. Resultados: El tiempo promedio de intervención quirúrgica fue de 22 minutos; 95,8% de los pacientes presentó evolución satisfactoria del postquirúrgico; 1,4% de los pacientes se reintervino para drenar un absceso intracavitario residual y 0,2% presentó infencción de sitio operatorio sin mas complicaciones. Conclusión: El abordaje transumbilical de la apendicitis es una alternativa minimamente invasiva para todos los estados de apendicitis aguda e implica disminución del tiempo de realización, menor estancia del postquirúrgico, menor incidencia de complicaciones y mayor conformidad con los resultados estéticos.

  9. The experience and awareness of laparoendoscopic procedures among Polish surgeons in everyday clinical practice.

    Science.gov (United States)

    Mitura, Kryspin; Dąbrowiecki, Stanisław; Śmietański, Maciej; Matyja, Andrzej

    2017-01-01

    In 2012, a total of 56 647 inguinal hernia repairs were performed in Poland. However, the absence of a uniform hernia repair register obscures the current herniology status in Poland, especially regarding laparoendoscopic procedures. To determine the awareness of laparoendoscopic procedures among Polish surgeons and to ascertain their everyday clinical practice. The data were collected at the national hernia conference in 2016, during an interactive session for surgeons with a special interest in herniology. They could respond to the survey items using the VoxVote application. All items and response options were displayed on participants' smartphones. The questions were related to transabdominal preperitoneal/totally extraperitoneal (TAPP/TEP) hernia repair. The surgeons responded to 27 questions regarding routine inguinal hernia repair. One hundred and six surgeons from all regions of Poland participated in the survey. 19.2% of respondents never inform patients about the possibility of performing laparoendoscopic repair. 45.2% admitted that they had referred a patient with a difficult inguinal hernia to another hospital or surgeon. Seventy-five percent stated they would be willing to perform TAPP/TEP if the reimbursement rates were more favourable. In bilateral hernias, 61.6% of the respondents perform a two-step open repair, while only 25% perform a single-stage laparoendoscopic repair of bilateral hernia. In women, only 13.3% perform laparoendoscopic hernia repairs, and 19.0% do not use mesh. The skill level to perform TAPP/TEP repair is still inadequate among Polish surgeons. The absence of accurate data makes it impossible to verify whether the treatment methods used are compliant with the guidelines.

  10. Single site laparoscopic right hemicolectomy: an oncological feasible option

    Directory of Open Access Journals (Sweden)

    Lim Yon Kuei

    2010-09-01

    Full Text Available Abstract Introduction We present the first 7 cases of single site right hemicolectomy in Asia using the new Single Site Laparoscopy (SSL access system from Ethicon Endo-surgery. Methods Right hemicolectomy was performed using the new Single Site Laparoscopy (SSL access system. Patient demographics, operative time, histology and post operative recovery and complications were collected and analysed. Results The median operative time was 90 mins (range 60 - 150 mins and a median wound size of 2.5 cm (range 2 to 4.5 cm. The median number of lymph nodes harvested was 24 (range 20 to 34 lymph nodes. The median length of proximal margin was 70 mm (range 30 to 145 mm and that of distal margin was 50 mm (35 to 120 mm. All patients had a median hospital stay of 7 days (range 5 to 11 and there were no significant perioperative complications except for 1 patient who had a minor myocardial event. Conclusion Right hemicolectomy using SSL access system is feasible and safe for oncologic surgery.

  11. Single-site neural tube closure in human embryos revisited.

    Science.gov (United States)

    de Bakker, Bernadette S; Driessen, Stan; Boukens, Bastiaan J D; van den Hoff, Maurice J B; Oostra, Roelof-Jan

    2017-10-01

    Since the multi-site closure theory was first proposed in 1991 as explanation for the preferential localizations of neural tube defects, the closure of the neural tube has been debated. Although the multi-site closure theory is much cited in clinical literature, single-site closure is most apparent in literature concerning embryology. Inspired by Victor Hamburgers (1900-2001) statement that "our real teacher has been and still is the embryo, who is, incidentally, the only teacher who is always right", we decided to critically review both theories of neural tube closure. To verify the theories of closure, we studied serial histological sections of 10 mouse embryos between 8.5 and 9.5 days of gestation and 18 human embryos of the Carnegie collection between Carnegie stage 9 (19-21 days) and 13 (28-32 days). Neural tube closure was histologically defined by the neuroepithelial remodeling of the two adjoining neural fold tips in the midline. We did not observe multiple fusion sites in neither mouse nor human embryos. A meta-analysis of case reports on neural tube defects showed that defects can occur at any level of the neural axis. Our data indicate that the human neural tube fuses at a single site and, therefore, we propose to reinstate the single-site closure theory for neural tube closure. We showed that neural tube defects are not restricted to a specific location, thereby refuting the reasoning underlying the multi-site closure theory. Clin. Anat. 30:988-999, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. Multifunctional Single-Site Catalysts for Alkoxycarbonylation of Terminal Alkynes.

    Science.gov (United States)

    Chen, Xingkun; Zhu, Hejun; Wang, Wenlong; Du, Hong; Wang, Tao; Yan, Li; Hu, Xiangping; Ding, Yunjie

    2016-09-08

    A multifunctional copolymer (PyPPh2 -SO3 H@porous organic polymers, POPs) was prepared by combining acidic groups and heterogeneous P,N ligands through the copolymerization of vinyl-functionalized 2-pyridyldiphenylphosphine (2-PyPPh2 ) and p-styrene sulfonic acid under solvothermal conditions. The morphology and chemical structure of the copolymer were evaluated using a series of characterization techniques. Compared with traditional homogeneous Pd(OAc)2 /2-PyPPh2 / p-toluenesulfonic acid catalyst, the copolymer supported palladium catalyst (Pd-PyPPh2 -SO3 H@POPs) exhibited higher activity for alkoxycarbonylation of terminal alkynes under the same conditions. This phenomenon could be attributed to the synergistic effect between the single-site Pd centers, 2-PyPPh2 ligands, and SO3 H groups, the outstanding swelling properties as well as the high enrichment of the reactant concentration by the porous catalyst. In addition, the catalyst could be reused at least 4 times without any apparent loss of activity. The excellent catalytic reactivity and good recycling properties make it an attractive catalyst for industrial applications. This work paves the way for advanced multifunctional porous organic polymers as a new type of platform for heterogeneous catalysis in the future. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Two-stage laparoscopic approaches for high anorectal malformation: transumbilical colostomy and anorectoplasty.

    Science.gov (United States)

    Yang, Li; Tang, Shao-Tao; Li, Shuai; Aubdoollah, T H; Cao, Guo-Qing; Lei, Hai-Yan; Wang, Xin-Xing

    2014-11-01

    Trans-umbilical colostomy (TUC) has been previously created in patients with Hirschsprung's disease and intermediate anorectal malformation (ARM), but not in patients with high-ARM. The purposes of this study were to assess the feasibility, safety, complications and cosmetic results of TUC in a divided fashion, and subsequently stoma closure and laparoscopic assisted anorectoplasty (LAARP) were simultaneously completed by using the colostomy site for a laparoscopic port in high-ARM patients. Twenty male patients with high-ARMs were chosen for this two-stage procedure. The first-stage consisted of creating the TUC in double-barreled fashion colostomy with a high chimney at the umbilicus, and the loop was divided at the same time, in such a way that the two diverting ends were located at the umbilical incision with the distal end half closed and slightly higher than proximal end. In the second-stage, 3 to 7 months later, the stoma was closed through a peristomal skin incision followed by end-to-end anastomosis and simultaneously LAARP was performed by placing a laparoscopic port at the umbilicus, which was previously the colonostomy site. Umbilical wound closure was performed in a semi-opened fashion to create a deep umbilicus. TUC and LAARP were successfully performed in 20 patients. Four cases with bladder neck fistulas and 16 cases with prostatic urethra fistulas were found. Postoperative complications were rectal mucosal prolapsed in three cases, anal stricture in two cases and wound dehiscence in one case. Neither umbilical ring narrowing, parastomal hernia nor obstructive symptoms was observed. Neither umbilical nor perineal wound infection was observed. Stoma care was easily carried-out by attaching stoma bag. Healing of umbilical wounds after the second-stage was excellent. Early functional stooling outcome were satisfactory. The umbilicus may be an alternative stoma site for double-barreled colostomy in high-ARM patients. The two-stage laparoscopic

  14. Olefin polymerization from single site catalysts confined within porous media

    Science.gov (United States)

    Kasi, Rajeswari M.

    Single Site Catalysts (SSCs) have been utilized for olefin polymerization. Altering the metal-ligand architecture in the SSCs, polyolefin properties can be enhanced in a rational manner. This influence of the ligands in the SSC on the property of polyolefins prepared can be referred to as the primary ligand influence. Extending this understanding and subsequent control of the metal-ligand framework to the interaction of SSCs within organic and inorganic supports is vital for the synthesis of polyolefins with tailored properties. The motivation behind this thesis was to explore the support influence on the reactivity of the SSC tethered to a support matrix during ethylene homo and copolymerization. In order to address this question of the support influence on the final polyolefin properties, synthetic routes to covalently bind SSCs on different matrices have been explored. Two distinct supported SSCs have been used to prepare branched polyethylenes. Branched polyethylenes can be prepared by either copolymerization (ethylene and alpha-olefin) or oligomerization/copolymerization processes (ethylene and in situ generated alpha-olefin). Synthetic routes to prepare precursor catalysts to Constrained Geometry Catalysts (CGCs) by silyl elimination chemistry have been developed (Chapter 2). Efficient synthetic protocols to assemble CGCs on aminomethylpolysytrene matrices (Chapter 3) and amine-functionalized mesoporous silica (Chapter 4) are also reported. These supported catalysts, with appropriate cocatalysts have been used to prepare ethylene homo and copolymers, the polymer thermal properties and microstructures were analyzed by various analytical techniques. Branched polyethylenes (LLDPE) can be prepared by copolymerization chemistry. It has been observed is that the influence of the support is seen in the production of lower crystalline forms of high density polyethylene (HDPE, 20--50% crystalline), while homogeneous polymerization of analogous soluble CGCs afford HDPE

  15. Current status of laparoendoscopic rendezvous in the treatment of cholelithiasis with concomitant choledocholithiasis.

    Science.gov (United States)

    Baloyiannis, Ioannis; Tzovaras, George

    2015-06-25

    The current evidence in favor of the laparoendoscopic rendezvous is promising and demonstrates the main advantages of this technique in regard to shorter hospital stay and selective cannulation of the common bile duct (CBD), avoiding thus the inadvertent cannulation of the pancreatic duct. In addition, in the rendezvous technique the contrast medium is not injected retrogradely as during the traditional endoscopic retrograde cholangiopancreatography (ERCP), when the medium accidentally could be injected under pressure into the pancreatic duct. The RV technique minimizes that risk. Both these main advantages of the RV technique over the classic ERCP, are related with a significant lower incidence of hyperamylasemia and post-ERCP pancreatitis, compared with the traditional two stage procedure. Choledocholithiasis is present in 10% to 15% of patients undergoing cholecystectomy. To date, the ideal management of CBD stones remains controversial. Prospective randomized trials have shown that laparoscopic management of the CBD stones, as a single stage procedure, is the most efficient and cost effective method of treatment. Laparoendoscopic rendezvous has been proposed as an alternative single stage approach. Several studies have shown the effective use of this technique in the treatment of CBD stones by improving patient compliance and clinical results including shorter hospital stay, higher success rate and less cost. The current evidence about the use of this technique presented in this review article is promising and demonstrates the main advantages of the procedure.

  16. Laparoendoscopic management of concomitant gallbladder stones and common bile duct stones: what is the best technique?

    Science.gov (United States)

    El-Geidie, Ahmed Abdel-Raouf

    2011-08-01

    The intraoperative use of endoscopic retrograde cholangiopancreatography (ERCP) during laparoscopic cholecystectomy (LC) is a safe, single-stage option for the management of concomitant gallstones (GS) and common bile duct stones (CBDS). This study aims to compare between 2 techniques of combined laparoendoscopic management, which are laparoendoscopic Rendez-vous (LC/LERV) technique and standard ERCP after the completion of LC intraoperative endoscopic sphincterotomy (IOES). Patients with GS and suspected CBDS were included. They were divided into 2 groups; LC/LERV and LC/IOES. Both groups were compared for failure of endoscopic sphincterotomy/stone extraction, operative time, conversion rate, mortality/morbidity, and length of hospital stay. Between October 2007 and February 2010, 98 patients with GS and CBDS were eligible for inclusion in the study. They were prospectively randomized into 2 groups; LC/LERV (N=45) and LC/IOES (N=53). There were no differences in preoperative parameters between both groups. There was a significant difference in operative time (shorter for LC/IOES). No difference was noted in success/failure rate, post-ERCP pancreatitis. Both Standard ERCP after the completion of LC and LC/LERV are valid single-session management for CBD stones, but LC-ERCP may be preferred.

  17. Supra-transumbilical laparotomy (STL approach for small bowel atresia repair: Our experience and review of the literature

    Directory of Open Access Journals (Sweden)

    Ernesto Leva

    2013-01-01

    Full Text Available Background: Supra-Transumbilical Laparotomy (STL has been used in paediatric surgery for a broad spectrum of abdominal procedures. We report our experience with STL approach for small bowel atresia repair in newborns and review previous published series on the topic. Patients and Methods: Fourteen patients with small bowel atresia were treated via STL approach at our Institution over a 5-year period and their charts were retrospectively reviewed. Results: STL procedure was performed at mean age of 3.1 day. No malrotation disorders were detected with pre-operative contrast enema. Eight patients (54.1% presented jejunal atresia, five (35.7% ileal atresia, and one (7.1% multiple ileal and jejunal atresias. Standard repair with primary end-to-back anastomosis was performed in all but one patient. In the newborn with multiple atresia, STL incision was converted in supra-umbilical transverse incision due to difficulty of exposition. After surgery, one patient developed anastomotic stricture, and another developed occlusion due to adhesions: Both infants required second laparotomy. No infections of the umbilical site were recorded, and cosmetic results were excellent in all patients. Conclusions: Increasing evidence suggests that STL approach for small bowel atresia is feasible, safe and provides adequate exposure for small bowel atresia surgery. When malrotation and colonic/multiple atresia are pre-operatively ruled out, STL procedure can be choosen as first approach.

  18. Robotic-assisted single-port donor nephrectomy using the da Vinci single-site platform.

    Science.gov (United States)

    LaMattina, John C; Alvarez-Casas, Josue; Lu, Irene; Powell, Jessica M; Sultan, Samuel; Phelan, Michael W; Barth, Rolf N

    2018-02-01

    Although single-port donor nephrectomy offers improved cosmetic outcomes, technical challenges have limited its application to selected centers. Our center has performed over 400 single-port donor nephrectomies. The da Vinci single-site robotic platform was utilized in an effort to overcome the steric, visualization, ergonomic, and other technical limitations associated with the single-port approach. Food and Drug Administration device exemption was obtained. Selection criteria for kidney donation included body mass index da Vinci single-site platform. Our experience supported the safety of this approach but found that the technology added cost and complexity without tangible benefit. Development of articulating instruments, energy, and stapling devices will be necessary for increased application of robotic single-site surgery for donor nephrectomy. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Single-Site Palladium(II) Catalyst for Oxidative Heck Reaction: Catalytic Performance and Kinetic Investigations

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Hui; Li, Mengyang; Zhang, Guanghui; Gallagher, James R.; Huang, Zhiliang; Sun, Yu; Luo, Zhong; Chen, Hongzhong; Miller, Jeffrey T.; Zou, Ruqiang; Lei, Aiwen; Zhao, Yanli

    2015-01-01

    ABSTRACT: The development of organometallic single-site catalysts (SSCs) has inspired the designs of new heterogeneous catalysts with high efficiency. Nevertheless, the application of SSCs in certain modern organic reactions, such as C-C bond formation reactions, has still been less investigated. In this study, a single-site Pd(II) catalyst was developed, where 2,2'-bipyridine-grafted periodic mesoporous organosilica (PMO) was employed as the support of a Pd(II) complex. The overall performance of the single-site Pd(II) catalyst in the oxidative Heck reaction was then investigated. The investigation results show that the catalyst displays over 99% selectivity for the product formation with high reaction yield. Kinetic profiles further confirm its high catalytic efficiency, showing that the rate constant is nearly 40 times higher than that for the free Pd(II) salt. X-ray absorption spectroscopy reveals that the catalyst has remarkable lifetime and recyclability.

  20. Efficacy of the Laparoendoscopic "Rendezvous" to Treat Cholecystocholedocholithiasis in 210 Consecutive Patients: A Single Center Experience.

    Science.gov (United States)

    La Greca, Gaetano; Pesce, Antonio; Vitale, Marco; Mannino, Maurizio; Di Marco, Federica; Di Blasi, Michele; Lombardo, Rosario; Puleo, Stefano; Russello, Domenico; Latteri, Saverio

    2017-08-01

    The simultaneous laparoendoscopic "rendezvous" (LERV) represents an alternative to sequential or totally laparoscopic approaches for patients affected by cholecystocholedocholithiasis. The aim of this study was to analyze the results in a large series of 210 consecutive patients. From 2002 to 2016 all patients affected by cholecystocholedocholithiasis were treated with a standardized "tailored" LERV. The relevant technical features of the procedure were recorded. An analysis of feasibility, effectiveness in stone clearance, and safety was performed. Among 214 patients with common bile duct stones, 210 were treated with LERV and 4 with open rendezvous approach. Intraoperative cholangiography confirmed common bile duct stones in 179 patients (85.2%) or sludge in 18 (8.5%) and in 98.9% stone clearance was obtained endoscopically. Endoscopic papilla cannulation was feasible in 161 patients (76.7%), whereas in 49 (23.3%) a transcystic guidewire was needed. The overall LERV feasibility was 96.6%. The conversion rate to open surgery was 3.3%. Minor morbidity was observed in 1.9% of cases, mortality in 0.47%, and the mean hospital stay was 4.3 days. These results confirm the high effectiveness of LERV. This approach to treat cholecystocholedocholithiasis should be preferred and therefore implemented where a strong collaboration between surgeons and endoscopists is possible.

  1. Ab initio calculations of partial molar properties in the single-site approximation

    DEFF Research Database (Denmark)

    Ruban, Andrei; Skriver, Hans Lomholt

    1997-01-01

    We discuss the application of the single-site approximation in calculations of partial molar quantities, e.g., impurity solution energy, segregation energy, and effective chemical potential, which are related to a variation of the composition of an alloy or its nonequivalent parts. We demonstrate...

  2. Robotic right colectomy using the Da Vinci Single-Site® platform: case report.

    Science.gov (United States)

    Morelli, Luca; Guadagni, Simone; Caprili, Giovanni; Di Candio, Giulio; Boggi, Ugo; Mosca, Franco

    2013-09-01

    While single-port laparoscopy for abdominal surgery is technically challenging, the Da Vinci Single-Site® robotic surgery platform may help to overcome some of the difficulties of this rapidly evolving technique. The authors of this article present a case of single-incision, robotic right colectomy using this device. A 74-year-old female with malignant polyp of caecum was operated on with a single-site approach using the Da Vinci Single-Site® robotic surgery device. Resection and anastomosis were performed extra-corporeally after undocking the robot. The procedure was successfully completed in 200 min. No surgical complications occurred during the intervention and the post-operative stay and no conversion to laparotomy or additional trocars were required. To the best of our knowledge, this is the first case of right colectomy using the Da Vinci Single-Site® robotic surgery platform to be reported. The procedure is feasible and safe and its main advantages are restoration of triangulation and reduced instrument clashes. Copyright © 2013 John Wiley & Sons, Ltd.

  3. Da Vinci single site© surgical platform in clinical practice: a systematic review.

    Science.gov (United States)

    Morelli, Luca; Guadagni, Simone; Di Franco, Gregorio; Palmeri, Matteo; Di Candio, Giulio; Mosca, Franco

    2016-12-01

    The Da Vinci single-site© surgical platform (DVSSP) is a set of single-site instruments and accessories specifically dedicated to robot-assisted single-site surgery. The PubMed database from inception to June 2015 was searched for English literature on the clinical use of DVSSP in general surgery, urology and gynecology. Twenty-nine articles involving the clinical application of DVSSP were identified; 15 articles on general surgery (561 procedures), four articles on urology (48 procedures) and 10 articles on gynecology (212 procedures). All studies have proven the safety and feasibility of the use of DVSSP. The principal reported advantage is the restoration of intra-abdominal triangulation, while the main reported limitation is the lack of the endowrist. Da Vinci systems have proven to be valuable assets in single-site surgery, owing to the combination of robot use with the dedicated single-incision platform. However, case-control or prospective trials are warranted to draw more definitive conc lusions. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  4. "Ultra-rapid" sequential treatment in cholecystocholedocholithiasis: alternative same-day approach to laparoendoscopic rendezvous.

    Science.gov (United States)

    Borreca, Dario; Bona, Alberto; Bellomo, Maria Paola; Borasi, Andrea; De Paolis, Paolo

    2015-12-01

    There is still no consensus about timing of laparoscopic cholecystectomy after endoscopic retrograde cholangiopancreatography in the treatment of cholecystocholedocholithiasis. The aim of our retrospective study is to analyze the optimal timing of surgical treatment in patients presenting concurrent choledocholithiasis, choosing to perform a sequential endoscopic plus surgical approach, introducing a same-day two-stage alternative. All cases of cholecystocholedocholithiasis occurred between January 2007 and December 2014 in "Gradenigo" Hospital (Turin-Italy) were reviewed. Patients were divided into three groups, based on the timing of cholecystectomy after endoscopic retrograde cholangiopancreatography, and compared. Out of 2233 cholecystectomies performed in the mentioned time interval, have been identified 93 patients that fulfill the selection criteria. 36 patients were treated with a same-day approach, while 29 within first 72 h and 28 with delayed surgery. The overall length of stay was significantly lower in patients that were treated with a same-day approach (4.7 days), compared with other groups (p = 0.001), while no significant differences were found in terms of length of surgical intervention, intraoperative complications and conversions to open procedure, postoperative stay, morbidity and mortality. Patients treated with delayed surgery had a 18 % recurrency rate of biliary events, with an odds ratio of 14.13 (p = 0.018). Same-day two-stage approach should be performed in suitable patients at the index admission, reducing overall risks, improving the patients' quality-of-life, preventing recurrency, leading to a significant cost abatement; furthermore, this approach allows same outcomes of laparoendoscopic rendezvous, avoiding technical and organizational troubles.

  5. Laparoendoscopic rendezvous in the treatment of cholecysto-choledocholitiasis: a single series of 200 patients.

    Science.gov (United States)

    La Barba, Giuliano; Gardini, Andrea; Cavargini, Elena; Casadei, Alessandro; Morgagni, Paolo; Bazzocchi, Francesca; D'Acapito, Fabrizio; Cavaliere, Davide; Curti, Roberta; Tringali, Domenico; Cucchetti, Alessandro; Ercolani, Giorgio

    2018-02-27

    Although the ideal management of cholecysto-choledocholitiasis is controversial, the two-stage approach, namely the common bile duct (CBD) clearance through endoscopic retrograde cholangiopancreatography (ERCP) followed by laparoscopic cholecystectomy, remains the standard way of management. However, whenever feasible, the one-stage approach, using the so-called "laparoendoscopic rendezvous" (LERV) technique, offers some advantages, mainly reducing the hospital stay and the risk of post-ERCP pancreatitis. The aim of this study was to evaluate the safety and the efficacy of the one-stage approach, and to compare our results with data from available large studies. We reviewed our series of consecutive patients with cholecysto-choledocholitiasis treated by LERV from January 2003, to October 2016. Both elective and emergency cases were included. The primary end-point was the efficacy to obtain the CBD stones clearance. Secondary end-points were morbidity and mortality, operative time, conversion rate, and in-hospital stay. A total of 200 patients underwent a LERV procedure for the intra-operative diagnosis by intra-operative cholangiogram of cholecysto-choledocholitiasis. In 187 patients (93.5%), it was possible to cannulate the cystic duct with the jag-wire. Success rate was 95%. Conversion rate was 3%. The mean operative time was 135 min and the mean in-hospital stay was 4 days. 29 (14.5%) were the early complications, six mild pancreatitis. Four patients required re-operation during the hospital stay. 11 patients (5.5%) developed late complications during a median follow-up of 57.7 months. Our results confirm that LERV technique is a safe procedure with high success rates for the treatment of cholecysto-choledocholitiasis. The major advantages include the single-stage treatment, the shorter hospital stay, and the lower incidence of post-ERCP pancreatitis.

  6. Cost analysis of laparoendoscopic rendezvous versus preoperative ERCP and laparoscopic cholecystectomy in the management of cholecystocholedocholithiasis.

    Science.gov (United States)

    Garbarini, Aldo; Reggio, Dario; Arolfo, Simone; Bruno, Marco; Passera, Roberto; Catalano, Giorgia; Barletti, Claudio; Salizzoni, Mauro; Morino, Mario; Petruzzelli, Luca; Arezzo, Alberto

    2017-08-01

    Evidence from controlled trials and meta-analyses suggests that laparoendoscopic rendezvous (LERV) is preferable to sequential treatment in the management of common bile duct stones. With this retrospective analysis of a prospective database that included consecutive patients treated for cholecystocholedocholithiasis at our institution between January 2007 and July 2015, we compared LERV with sequential treatment. The primary endpoint was global cost, defined as the cost/patient/hospital stay, and the secondary end points were efficacy and morbidity. Fisher's exact test or Mann-Whitney test was used. Of a total of 249 consecutive patients, 143 underwent LERV (group A) and 106 a two-stage procedure (group B). Based on an average cost of €613 for 1 day of hospital stay in the General Surgery Department, the overall median cost of treatment was €6403 for group A and €8194 for group B (p < 0.001). Operative time was significantly shorter (p < 0.001), and length of hospital stay was significantly longer for group B (p < 0.001). No mortality in either group was observed. The postoperative complications rate was significantly higher in group B than in group A (24.5 vs. 10.5%; p = 0.003). No significant difference in the postoperative pancreatitis rate or the number of patients with increased serum amylase at 24 h was observed in either group. Our study suggests that LERV is preferable to sequential treatment not only in terms of less morbidity, but also of lower costs accrued by a shorter hospital stay. However, the longer operative time raises multiple organizational issues in the coordination of surgery and endoscopy services.

  7. Laparoendoscopic Rendezvous for Concomitant Cholecystocholedocholithiasis: A Successful Modality Even in the Most Difficult Presentations Including Pregnancy.

    Science.gov (United States)

    Shirah, Bader Hamza; Mikwar, Zaher Abdulaziz; Ahmad, Akram Neyaz; Dahlan, Yaser Mohammed

    2016-01-01

    Background . Laparoendoscopic rendezvous (LERV) technique is emerging as an attractive treatment option for concomitant cholecystocholedocholithiasis. In this paper, we report our experience in performing the LERV technique in patients with unusual presentations in terms of anatomical difficulty, pregnancy, multiple comorbid diseases, and postlaparotomy. We aim to highlight the effectiveness of the LERV technique in some clinical situations where conventional methods would fail or carry high risks in adequately managing concomitant cholecystocholedocholithiasis. Methods . Four patients diagnosed to have concomitant cholecystocholedocholithiasis with associated difficult presentation or comorbid diseases were treated using the LERV technique. One patient presented with difficult anatomy where ERCP failed at initial attempts. Another patient was pregnant (first trimester). A third patient had complex comorbid diseases (bronchial asthma, hypertension, congestive heart failure, and end-stage renal disease on regular hemodialysis). A fourth patient had previous laparotomy and sigmoidectomy for diverticular disease and had severe hospital phobia. Results . All patients tolerated the LERV technique very well; no intraoperative occurrence was reported. The mean operative time was 86.3 ± 17.2 minutes; mean time of the endoscopic part was 29.4 ± 3.57 minutes. The mean blood loss was 44.3 ± 18.2 mL (range 20-85). Residual stone, postoperative complications, postoperative morbidity, and postoperative mortality were 0 (0%). Postoperative short hospital stay was reported in all patients, average 3 days (range 2-4). Conclusion . LERV procedure is a safe and effective treatment option for the management of concomitant cholecystocholedocholithiasis, even in difficult situations where other methods would fail or carry high risks, or in patients presenting with severe comorbid diseases or pregnancy. This procedure may emerge as an attractive alternative option for high

  8. [Transgastric laparo-endoscopic approach for difficult access lesions. Experimental mode].

    Science.gov (United States)

    Tapia-Vega, Marcel Adalid; Morales-Chávez, Carlos Ernesto; Aguirre-Olmedo, Itzé; Cuendis-Velázquez, Adolfo; Rojano-Rodríguez, Martín Edgardo; Cárdenas-Lailson, Luis Eduardo

    2014-01-01

    Gastric neoplasms can be treated by laparoscopy in a safe and efficient way. Some lesions are not accessible to laparoscopic surgery due to their location. A transgastric approach is proposed as an alternative. Show the results with the application of an endoscopic laparotomy in an animal model that maintains functional anatomy, to resect the posterior gastric neoplasms of the stomach wall, close to the cardia and pre-pyloric region. The laparo-endoscopic technique for resection of gastric neoplasms located in the posterior wall was developed in twelve pigs at the Hospital General Gea González from May to December 2011. An endoscopy was performed to establish the site of insertion of intragastric trocars. Three gastrotomies were made in the anterior wall; under endoscopic and laparoscopic vision the trocars were inserted. The stomach was insufflated with CO2. The lesion was resected maintaining a 20 mm circumferencial margin. The gastrotomies were sutured. The statistic analysis was made with t Student and exact Fisher tests. One-hundred percent of resections were achieved in an average time of 102.33 minutes (± 4.50). Two complications and no transoperatory deceases occurred. The technique we describe allows an appropriate approach to gastric lesions located in the posterior wall, those near to the esophagogastric juntion and the prepiloric region, due to the excellent exposure managed by working inside the stomach with a laparoscopic vision and the two intragastric movile ports. The laparoscopic transgastric approach is feasible and safe for the resection of gastric neoplasms located in the posterior wall, those close to the esophago-gastric junction, and the pre-pyloric region.

  9. Laparoendoscopic transgastric histoacryl injection of gastric varices: a new surgical approach.

    Science.gov (United States)

    Kassem, Mohamed I; El-Haddad, Hani M; El-Bahrawi, Hassan A

    2013-02-01

    Gastric varices (GVs) are a common finding in Egyptian patients with portal hypertension due to cirrhosis or schistosomal hepatic fibrosis. These patients present with an acute attack or history of hematemesis. Endoscopic histoacryl injection is the standard treatment in Egypt; however, because of technical difficulties it is possible to inject only a little amount of this material, as it may endanger the channels of the flexible endoscope. We thought of a new surgical laparoendoscopic technique to obviate the need for repeated endoscopies and complete obliteration of GVs. This study was conducted on 20 patients with portal hypertension and GVs. After the patient was placed under general anesthesia, a small gastrostomy was done in the anterior gastric wall through which a 10-mm trocar was inserted for the laparoscopic camera. Injection of GVs was done via a spinal needle or a central venous line needle inserted directly. Injection of an adequate amount of histoacryl was done under direct vision. This study was conducted from July 2009 to August 2011 on 20 patients with GVs. The age range was from 22 to 56 years, with a mean age of 39.8±7.85 years. There were 14 men (70%) and 6 women (30%). Fourteen patients (70%) showed complete obliteration of GVs after one session of treatment, whereas 6 patients (30%) had unsatisfactory results and were subjected to another session. GVs were completely obliterated after the second session in 4 patients. Two cases of recurrence of GVs were operated on. This new technique enabled us to inject GVs with a suitable amount of glue material under direct vision without harming the endoscope. Use of this procedure is recommended in patients fit for surgery and those who had failed endoscopic injection sclerotherapy.

  10. Laparoendoscopic Rendezvous for Concomitant Cholecystocholedocholithiasis: A Successful Modality Even in the Most Difficult Presentations Including Pregnancy

    Directory of Open Access Journals (Sweden)

    Bader Hamza Shirah

    2016-01-01

    Full Text Available Background. Laparoendoscopic rendezvous (LERV technique is emerging as an attractive treatment option for concomitant cholecystocholedocholithiasis. In this paper, we report our experience in performing the LERV technique in patients with unusual presentations in terms of anatomical difficulty, pregnancy, multiple comorbid diseases, and postlaparotomy. We aim to highlight the effectiveness of the LERV technique in some clinical situations where conventional methods would fail or carry high risks in adequately managing concomitant cholecystocholedocholithiasis. Methods. Four patients diagnosed to have concomitant cholecystocholedocholithiasis with associated difficult presentation or comorbid diseases were treated using the LERV technique. One patient presented with difficult anatomy where ERCP failed at initial attempts. Another patient was pregnant (first trimester. A third patient had complex comorbid diseases (bronchial asthma, hypertension, congestive heart failure, and end-stage renal disease on regular hemodialysis. A fourth patient had previous laparotomy and sigmoidectomy for diverticular disease and had severe hospital phobia. Results. All patients tolerated the LERV technique very well; no intraoperative occurrence was reported. The mean operative time was 86.3±17.2 minutes; mean time of the endoscopic part was 29.4±3.57 minutes. The mean blood loss was 44.3±18.2 mL (range 20–85. Residual stone, postoperative complications, postoperative morbidity, and postoperative mortality were 0 (0%. Postoperative short hospital stay was reported in all patients, average 3 days (range 2–4. Conclusion. LERV procedure is a safe and effective treatment option for the management of concomitant cholecystocholedocholithiasis, even in difficult situations where other methods would fail or carry high risks, or in patients presenting with severe comorbid diseases or pregnancy. This procedure may emerge as an attractive alternative option for high

  11. A comparative study on trans-umbilical single-port laparoscopic approach versus conventional repair for incarcerated inguinal hernia in children

    Directory of Open Access Journals (Sweden)

    Zhang Jun

    2016-01-01

    Full Text Available Purpose: The purpose of this study is to determine whether singleport laparoscopic repair (SLR for incarcerated inguinal hernia in children is superior toconventional repair (CR approaches. Method: Between March 2013 and September 2013, 126 infants and children treatedwere retrospectively reviewed. All the patients were divided into three groups. Group A (48 patients underwent trans-umbilical SLR, group B (36 patients was subjected to trans-umbilical conventional two-port laparoscopic repair (TLR while the conventional open surgery repair (COR was performed in group C (42 patients. Data regarding the operating time, bleeding volume, post-operative hydrocele formation, testicular atrophy, cosmetic results, recurrence rate, and duration of hospital stay of the patients were collected. Result: All the cases were completed successfully without conversion. The mean operative time for group A was 15 ± 3.9 min and 24 ± 7.2 min for unilateral hernia and bilateral hernia respectively, whereas for group B, it was 13 ± 6.7 min and 23 ± 9.2 min. The mean duration of surgery in group C was 35 ± 5.2 min for unilateral hernia. The recurrence rate was 0% in all the three groups. There were statistically significant differences in theoperating time, bleeding volume, post-operative hydrocele formation, cosmetic results and duration hospital stay between the three groups (P < 0.001. No statistically significant differences between SLR and TLR were observed except the more cosmetic result in SLR. Conclusion: SLR is safe and effective, minimally invasive, and is a new technology worth promoting.

  12. A comparative study on trans-umbilical single-port laparoscopic approach versus conventional repair for incarcerated inguinal hernia in children.

    Science.gov (United States)

    Jun, Zhang; Juntao, Ge; Shuli, Liu; Li, Long

    2016-01-01

    The purpose of this study is to determine whether singleport laparoscopic repair (SLR) for incarcerated inguinal hernia in children is superior toconventional repair (CR) approaches. Between March 2013 and September 2013, 126 infants and children treatedwere retrospectively reviewed. All the patients were divided into three groups. Group A (48 patients) underwent trans-umbilical SLR, group B (36 patients) was subjected to trans-umbilical conventional two-port laparoscopic repair (TLR) while the conventional open surgery repair (COR) was performed in group C (42 patients). Data regarding the operating time, bleeding volume, post-operative hydrocele formation, testicular atrophy, cosmetic results, recurrence rate, and duration of hospital stay of the patients were collected. All the cases were completed successfully without conversion. The mean operative time for group A was 15 ± 3.9 min and 24 ± 7.2 min for unilateral hernia and bilateral hernia respectively, whereas for group B, it was 13 ± 6.7 min and 23 ± 9.2 min. The mean duration of surgery in group C was 35 ± 5.2 min for unilateral hernia. The recurrence rate was 0% in all the three groups. There were statistically significant differences in theoperating time, bleeding volume, post-operative hydrocele formation, cosmetic results and duration hospital stay between the three groups (P < 0.001). No statistically significant differences between SLR and TLR were observed except the more cosmetic result in SLR. SLR is safe and effective, minimally invasive, and is a new technology worth promoting.

  13. Single-site catalyst promoters accelerate metal-catalyzed nitroarene hydrogenation

    KAUST Repository

    Wang, Liang

    2018-04-04

    Atomically dispersed supported metal catalysts are drawing wide attention because of the opportunities they offer for new catalytic properties combined with efficient use of the metals. We extend this class of materials to catalysts that incorporate atomically dispersed metal atoms as promoters. The catalysts are used for the challenging nitroarene hydrogenation and found to have both high activity and selectivity. The promoters are single-site Sn on TiO2 supports that incorporate metal nanoparticle catalysts. Represented as M/Sn-TiO2 (M = Au, Ru, Pt, Ni), these catalysts decidedly outperform the unpromoted supported metals, even for hydrogenation of nitroarenes substituted with various reducible groups. The high activity and selectivity of these catalysts result from the creation of oxygen vacancies on the TiO2 surface by single-site Sn, which leads to efficient, selective activation of the nitro group coupled with a reaction involving hydrogen atoms activated on metal nanoparticles.

  14. Single-site catalyst promoters accelerate metal-catalyzed nitroarene hydrogenation

    KAUST Repository

    Wang, Liang; Guan, Erjia; Zhang, Jian; Yang, Junhao; Zhu, Yihan; Han, Yu; Yang, Ming; Cen, Cheng; Fu, Gang; Gates, Bruce C.; Xiao, Feng-Shou

    2018-01-01

    Atomically dispersed supported metal catalysts are drawing wide attention because of the opportunities they offer for new catalytic properties combined with efficient use of the metals. We extend this class of materials to catalysts that incorporate atomically dispersed metal atoms as promoters. The catalysts are used for the challenging nitroarene hydrogenation and found to have both high activity and selectivity. The promoters are single-site Sn on TiO2 supports that incorporate metal nanoparticle catalysts. Represented as M/Sn-TiO2 (M = Au, Ru, Pt, Ni), these catalysts decidedly outperform the unpromoted supported metals, even for hydrogenation of nitroarenes substituted with various reducible groups. The high activity and selectivity of these catalysts result from the creation of oxygen vacancies on the TiO2 surface by single-site Sn, which leads to efficient, selective activation of the nitro group coupled with a reaction involving hydrogen atoms activated on metal nanoparticles.

  15. Well-defined single-site monohydride silica-supported zirconium from azazirconacyclopropane

    KAUST Repository

    Hamzaoui, Bilel

    2015-01-13

    The silica-supported azazirconacyclopropane ≡SiOZr(HNMe2)(η2-NMeCH2)(NMe2) (1) leads exclusively under hydrogenolysis conditions (H2, 150°C) to the single-site monopodal monohydride silica-supported zirconium species ≡SiOZr(HNMe2)(NMe2)2H (2). Reactivity studies by contacting compound 2 with ethylene, hydrogen/ethylene, propene, or hydrogen/propene, at a temperature of 200°C revealed alkene hydrogenation.

  16. Well-defined single-site monohydride silica-supported zirconium from azazirconacyclopropane

    KAUST Repository

    Hamzaoui, Bilel; El Eter, Mohamad; Abou-Hamad, Edy; Chen, Yin; Pelletier, Jeremie; Basset, Jean-Marie

    2015-01-01

    The silica-supported azazirconacyclopropane ≡SiOZr(HNMe2)(η2-NMeCH2)(NMe2) (1) leads exclusively under hydrogenolysis conditions (H2, 150°C) to the single-site monopodal monohydride silica-supported zirconium species ≡SiOZr(HNMe2)(NMe2)2H (2). Reactivity studies by contacting compound 2 with ethylene, hydrogen/ethylene, propene, or hydrogen/propene, at a temperature of 200°C revealed alkene hydrogenation.

  17. Ligand-tailored single-site silica supported titanium catalysts: Synthesis, characterization and towards cyanosilylation reaction

    International Nuclear Information System (INIS)

    Xu, Wei; Li, Yani; Yu, Bo; Yang, Jindou; Zhang, Ying; Chen, Xi; Zhang, Guofang; Gao, Ziwei

    2015-01-01

    A successive anchoring of Ti(NMe 2 ) 4 , cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on silica was conducted by SOMC strategy in moderate conditions. The silica, monitored by in-situ Fourier transform infrared spectroscopy (in-situ FT-IR), was pretreated at different temperatures (200, 500 and 800 °C). The ligand tailored silica-supported titanium complexes were characterized by in-situ FT-IR, 13 C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) and elemental analysis in detail, verifying that the surface titanium species are single sited. The catalytic activity of the ligand tailored single-site silica supported titanium complexes was evaluated by a cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the dehydroxylation temperatures of silica and the configuration of the ligands. - Graphical abstract: The ligand-tailored silica supported “single site” titanium complexes were synthesized by SOMC strategy and fully characterized. Their catalytic activity were evaluated by benzaldehyde silylcyanation. - Highlights: • Single-site silica supported Ti active species was prepared by SOMC technique. • O-donor ligand tailored Ti surface species was synthesized. • The surface species was characterized by XPS, 13 C CP-MAS NMR, XANES etc. • Catalytic activity of the Ti active species in silylcyanation reaction was evaluated

  18. Housing Retention in Single-Site Housing First for Chronically Homeless Individuals With Severe Alcohol Problems

    Science.gov (United States)

    Malone, Daniel K.; Clifasefi, Seema L.

    2013-01-01

    Objectives. We studied housing retention and its predictors in the single-site Housing First model. Methods. Participants (n = 111) were chronically homeless people with severe alcohol problems who lived in a single-site Housing First program and participated in a larger nonrandomized controlled trial (2005–2008) conducted in Seattle, Washington. At baseline, participants responded to self-report questionnaires assessing demographic, illness burden, alcohol and other drug use, and psychiatric variables. Housing status was recorded over 2 years. Results. Participants were interested in housing, although a sizable minority did not believe they would be able to maintain abstinence-based housing. Only 23% of participants returned to homelessness during the 2-year follow-up. Commonly cited risk factors—alcohol and other drug use, illness burden, psychiatric symptoms, and homelessness history—did not predict resumed homelessness. Active drinkers were more likely to stay in this housing project than nondrinkers. Conclusions. We found that single-site Housing First programming fills a gap in housing options for chronically homeless people with severe alcohol problems. PMID:24148063

  19. Ligand-tailored single-site silica supported titanium catalysts: Synthesis, characterization and towards cyanosilylation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wei; Li, Yani; Yu, Bo; Yang, Jindou; Zhang, Ying; Chen, Xi; Zhang, Guofang, E-mail: gfzhang@snnu.edu.cn; Gao, Ziwei, E-mail: zwgao@snnu.edu.cn

    2015-01-15

    A successive anchoring of Ti(NMe{sub 2}){sub 4}, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on silica was conducted by SOMC strategy in moderate conditions. The silica, monitored by in-situ Fourier transform infrared spectroscopy (in-situ FT-IR), was pretreated at different temperatures (200, 500 and 800 °C). The ligand tailored silica-supported titanium complexes were characterized by in-situ FT-IR, {sup 13}C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) and elemental analysis in detail, verifying that the surface titanium species are single sited. The catalytic activity of the ligand tailored single-site silica supported titanium complexes was evaluated by a cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the dehydroxylation temperatures of silica and the configuration of the ligands. - Graphical abstract: The ligand-tailored silica supported “single site” titanium complexes were synthesized by SOMC strategy and fully characterized. Their catalytic activity were evaluated by benzaldehyde silylcyanation. - Highlights: • Single-site silica supported Ti active species was prepared by SOMC technique. • O-donor ligand tailored Ti surface species was synthesized. • The surface species was characterized by XPS, {sup 13}C CP-MAS NMR, XANES etc. • Catalytic activity of the Ti active species in silylcyanation reaction was evaluated.

  20. Reactivity of a Carbon-Supported Single-Site Molybdenum Dioxo Catalyst for Biodiesel Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Mouat, Aidan R.; Lohr, Tracy L.; Wegener, Evan C.; Miller, Jeffrey T.; Delferro, Massimiliano; Stair, Peter C.; Marks, Tobin J.

    2016-08-23

    A single-site molybdenum dioxo catalyst, (Oc)2Mo(=O)2@C, was prepared via direct grafting of MoO2Cl2(dme) (dme = 1,2-dimethoxyethane) on high-surface- area activated carbon. The physicochemical and chemical properties of this catalyst were fully characterized by N2 physisorption, ICP-AES/OES, PXRD, STEM, XPS, XAS, temperature-programmed reduction with H2 (TPR-H2), and temperature-programmed NH3 desorption (TPD-NH3). The single-site nature of the Mo species is corroborated by XPS and TPR-H2 data, and it exhibits the lowest reported MoOx Tmax of reduction reported to date, suggesting a highly reactive MoVI center. (Oc)2Mo(=O)2@C catalyzes the transesterification of a variety of esters and triglycerides with ethanol, exhibiting high activity at moderate temperatures (60-90 °C) and with negligible deactivation. (Oc)2Mo(=O)2@C is resistant to water and can be recycled at least three times with no loss of activity. The transesterification reaction is determined experimentally to be first order in [ethanol] and first order in [Mo] with ΔH = 10.5(8) kcal mol-1 and ΔS = -32(2) eu. The low energy of activation is consistent with the moderate conditions needed to achieve rapid turnover. This highly active carbon-supported single-site molybdenum dioxo species is thus an efficient, robust, and lowcost catalyst with significant potential for transesterification processes.

  1. On multi-site damage identification using single-site training data

    Science.gov (United States)

    Barthorpe, R. J.; Manson, G.; Worden, K.

    2017-11-01

    This paper proposes a methodology for developing multi-site damage location systems for engineering structures that can be trained using single-site damaged state data only. The methodology involves training a sequence of binary classifiers based upon single-site damage data and combining the developed classifiers into a robust multi-class damage locator. In this way, the multi-site damage identification problem may be decomposed into a sequence of binary decisions. In this paper Support Vector Classifiers are adopted as the means of making these binary decisions. The proposed methodology represents an advancement on the state of the art in the field of multi-site damage identification which require either: (1) full damaged state data from single- and multi-site damage cases or (2) the development of a physics-based model to make multi-site model predictions. The potential benefit of the proposed methodology is that a significantly reduced number of recorded damage states may be required in order to train a multi-site damage locator without recourse to physics-based model predictions. In this paper it is first demonstrated that Support Vector Classification represents an appropriate approach to the multi-site damage location problem, with methods for combining binary classifiers discussed. Next, the proposed methodology is demonstrated and evaluated through application to a real engineering structure - a Piper Tomahawk trainer aircraft wing - with its performance compared to classifiers trained using the full damaged-state dataset.

  2. Ligand-tailored single-site silica supported titanium catalysts: Synthesis, characterization and towards cyanosilylation reaction

    Science.gov (United States)

    Xu, Wei; Li, Yani; Yu, Bo; Yang, Jindou; Zhang, Ying; Chen, Xi; Zhang, Guofang; Gao, Ziwei

    2015-01-01

    A successive anchoring of Ti(NMe2)4, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1‧-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on silica was conducted by SOMC strategy in moderate conditions. The silica, monitored by in-situ Fourier transform infrared spectroscopy (in-situ FT-IR), was pretreated at different temperatures (200, 500 and 800 °C). The ligand tailored silica-supported titanium complexes were characterized by in-situ FT-IR, 13C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) and elemental analysis in detail, verifying that the surface titanium species are single sited. The catalytic activity of the ligand tailored single-site silica supported titanium complexes was evaluated by a cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the dehydroxylation temperatures of silica and the configuration of the ligands.

  3. Single-Site Tetracoordinated Aluminum Hydride Supported on Mesoporous Silica. From Dream to Reality!

    KAUST Repository

    Werghi, Baraa

    2016-09-26

    The reaction of mesoporous silica (SBA15) dehydroxylated at 700 °C with diisobutylaluminum hydride, i-Bu2AlH, gives after thermal treatment a single-site tetrahedral aluminum hydride with high selectivity. The starting aluminum isobutyl and the final aluminum hydride have been fully characterized by FT-IR, advanced SS NMR spectroscopy (1H, 13C, multiple quanta (MQ) 2D 1H-1H, and 27Al), and elemental analysis, while DFT calculations provide a rationalization of the occurring reactivity. Trimeric i-Bu2AlH reacts selectively with surface silanols without affecting the siloxane bridges. Its analogous hydride catalyzes ethylene polymerization. Indeed, catalytic tests show that this single aluminum hydride site is active in the production of a high-density polyethylene (HDPE). © 2016 American Chemical Society.

  4. Single-Site Tetracoordinated Aluminum Hydride Supported on Mesoporous Silica. From Dream to Reality!

    KAUST Repository

    Werghi, Baraa; Bendjeriou-Sedjerari, Anissa; Jedidi, Abdesslem; Abou-Hamad, Edy; Cavallo, Luigi; Basset, Jean-Marie

    2016-01-01

    The reaction of mesoporous silica (SBA15) dehydroxylated at 700 °C with diisobutylaluminum hydride, i-Bu2AlH, gives after thermal treatment a single-site tetrahedral aluminum hydride with high selectivity. The starting aluminum isobutyl and the final aluminum hydride have been fully characterized by FT-IR, advanced SS NMR spectroscopy (1H, 13C, multiple quanta (MQ) 2D 1H-1H, and 27Al), and elemental analysis, while DFT calculations provide a rationalization of the occurring reactivity. Trimeric i-Bu2AlH reacts selectively with surface silanols without affecting the siloxane bridges. Its analogous hydride catalyzes ethylene polymerization. Indeed, catalytic tests show that this single aluminum hydride site is active in the production of a high-density polyethylene (HDPE). © 2016 American Chemical Society.

  5. Minimally invasive single-site surgery for the digestive system: A technological review

    Directory of Open Access Journals (Sweden)

    Dhumane Parag

    2011-01-01

    Full Text Available Minimally Invasive Single Site (MISS surgery is a better terminology to explain the novel concept of scarless surgery, which is increasingly making its way into clinical practice. But, there are some difficulties. We review the existing technologies for MISS surgery with regards to single-port devices, endoscope and camera, instruments, retractors and also the future perspectives for the evolution of MISS surgery. While we need to move ahead cautiously and wait for the development of appropriate technology, we believe that the "Ultimate form of Minimally Invasive Surgery" will be a hybrid form of MISS surgery and Natural Orifice Transluminal Endoscopic Surgery, complimented by technological innovations from the fields of robotics and computer-assisted surgery.

  6. Chemoselective single-site Earth-abundant metal catalysts at metal–organic framework nodes

    Energy Technology Data Exchange (ETDEWEB)

    Manna, Kuntal; Ji, Pengfei; Lin, Zekai; Greene, Francis X.; Urban, Ania; Thacker, Nathan C.; Lin, Wenbin (UC)

    2016-08-30

    Earth-abundant metal catalysts are critically needed for sustainable chemical synthesis. Here we report a simple, cheap and effective strategy of producing novel earth-abundant metal catalysts at metal–organic framework (MOF) nodes for broad-scope organic transformations. The straightforward metalation of MOF secondary building units (SBUs) with cobalt and iron salts affords highly active and reusable single-site solid catalysts for a range of organic reactions, including chemoselective borylation, silylation and amination of benzylic C–H bonds, as well as hydrogenation and hydroboration of alkenes and ketones. Our structural, spectroscopic and kinetic studies suggest that chemoselective organic transformations occur on site-isolated, electron-deficient and coordinatively unsaturated metal centres at the SBUs via σ-bond metathesis pathways and as a result of the steric environment around the catalytic site. MOFs thus provide a novel platform for the development of highly active and affordable base metal catalysts for the sustainable synthesis of fine chemicals.

  7. Single-site SBA-15 supported zirconium catalysts. Synthesis, characterization and toward cyanosilylation reaction

    International Nuclear Information System (INIS)

    Xu, Wei; Yu, Bo; Zhang, Ying; Chen, Xi; Zhang, Guofang; Gao, Ziwei

    2015-01-01

    Graphical abstract: Ligand-modified signal-site SBA-15 supported zirconium catalysts were synthesized by SOMC method and characterized by a variety of techniques. The zirconium surface complexes show high catalytic efficiency for cyanosilylation of benzaldehyde. - Highlights: • Some Zr active species have been anchored on the surface of SBA-15 by SOMC technique. • The structures of the Zr species have been characterized by a variety of techniques. • The anchored Zr species are single-sited surface complexes. • The Zr surface complexes are catalytic active for cyanosilylation of benzaldehyde. - Abstract: A successive anchoring of Zr(NMe 2 ) 4 , cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on dehydroxylated SBA-15 pretreated at 500 °C for 16 h (SBA-15 -500 ) was conducted by SOMC strategy in moderate conditions. The dehydoxylation of SBA-15 was monitored by in situ Fourier transform infrared spectroscopy (in situ FT-IR). The ligand-modified SBA-15 -500 supported zirconium complexes were characterized by in situ FT-IR, 13 C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MAS) and elemental analysis in detail, verifying that the surface zirconium species are single-sited. The catalytic activity of these complexes was evaluated by cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the structure of surface species and the configuration of the ligands

  8. Single-site SBA-15 supported zirconium catalysts. Synthesis, characterization and toward cyanosilylation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wei; Yu, Bo; Zhang, Ying; Chen, Xi; Zhang, Guofang, E-mail: gfzhang@snnu.edu.cn; Gao, Ziwei, E-mail: zwgao@snnu.edu.cn

    2015-01-15

    Graphical abstract: Ligand-modified signal-site SBA-15 supported zirconium catalysts were synthesized by SOMC method and characterized by a variety of techniques. The zirconium surface complexes show high catalytic efficiency for cyanosilylation of benzaldehyde. - Highlights: • Some Zr active species have been anchored on the surface of SBA-15 by SOMC technique. • The structures of the Zr species have been characterized by a variety of techniques. • The anchored Zr species are single-sited surface complexes. • The Zr surface complexes are catalytic active for cyanosilylation of benzaldehyde. - Abstract: A successive anchoring of Zr(NMe{sub 2}){sub 4}, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on dehydroxylated SBA-15 pretreated at 500 °C for 16 h (SBA-15{sub -500}) was conducted by SOMC strategy in moderate conditions. The dehydoxylation of SBA-15 was monitored by in situ Fourier transform infrared spectroscopy (in situ FT-IR). The ligand-modified SBA-15{sub -500} supported zirconium complexes were characterized by in situ FT-IR, {sup 13}C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MAS) and elemental analysis in detail, verifying that the surface zirconium species are single-sited. The catalytic activity of these complexes was evaluated by cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the structure of surface species and the configuration of the ligands.

  9. Catalysis by Design: Well-Defined Single-Site Heterogeneous Catalysts

    KAUST Repository

    Pelletier, Jeremie

    2016-03-09

    ConspectusHeterogeneous catalysis, a field important industrially and scientifically, is increasingly seeking and refining strategies to render itself more predictable. The main issue is due to the nature and the population of catalytically active sites. Their number is generally low to very low, their "acid strengths" or " redox properties" are not homogeneous, and the material may display related yet inactive sites on the same material. In many heterogeneous catalysts, the discovery of a structure-activity reationship is at best challenging. One possible solution is to generate single-site catalysts in which most, if not all, of the sites are structurally identical. Within this context and using the right tools, the catalyst structure can be designed and well-defined, to reach a molecular understanding. It is then feasible to understand the structure-activity relationship and to develop predictable heterogeneous catalysis. Single-site well-defined heterogeneous catalysts can be prepared using concepts and tools of surface organometallic chemistry (SOMC). This approach operates by reacting organometallic compounds with surfaces of highly divided oxides (or of metal nanoparticles). This strategy has a solid track record to reveal structure-activity relationship to the extent that it is becoming now quite predictable. Almost all elements of the periodical table have been grafted on surfaces of oxides (from simple oxides such as silica or alumina to more sophisticated materials regarding composition or porosity).Considering catalytic hydrocarbon transformations, heterogeneous catalysis outcome may now be predicted based on existing mechanistic proposals and the rules of molecular chemistry (organometallic, organic) associated with some concepts of surface sciences. A thorough characterization of the grafted metal centers must be carried out using tools spanning from molecular organometallic or surface chemistry. By selection of the metal, its ligand set, and the

  10. Exploiting nanospace for asymmetric catalysis: confinement of immobilized, single-site chiral catalysts enhances enantioselectivity.

    Science.gov (United States)

    Thomas, John Meurig; Raja, Robert

    2008-06-01

    In the mid-1990s, it became possible to prepare high-area silicas having pore diameters controllably adjustable in the range ca. 20-200 Å. Moreover, the inner walls of these nanoporous solids could be functionalized to yield single-site, chiral, catalytically active organometallic centers, the precise structures of which could be determined using in situ X-ray absorption and FTIR and multinuclear magic angle spinning (MAS) NMR spectroscopy. This approach opened up the prospect of performing heterogeneous enantioselective conversions in a novel manner, under the spatial restrictions imposed by the nanocavities within which the reactions occur. In particular, it suggested an alternative method for preparing pharmaceutically and agrochemically useful asymmetric products by capitalizing on the notion, initially tentatively perceived, that spatial confinement of prochiral reactants (and transition states formed at the chiral active center) would provide an altogether new method of boosting the enantioselectivity of the anchored chiral catalyst. Initially, we anchored chiral single-site heterogeneous catalysts to nanopores covalently via a ligand attached to Pd(II) or Rh(I) centers. Later, we employed a more convenient and cheaper electrostatic method, relying in part on strong hydrogen bonding. This Account provides many examples of these processes, encompassing hydrogenations, oxidations, and aminations. Of particular note is the facile synthesis from methyl benzoylformate of methyl mandelate, which is a precursor in the synthesis of pemoline, a stimulant of the central nervous system; our procedure offers several viable methods for reducing ketocarboxylic acids. In addition to relying on earlier (synchrotron-based) in situ techniques for characterizing catalysts, we have constructed experimental procedures involving robotically controlled catalytic reactors that allow the kinetics of conversion and enantioselectivity to be monitored continually, and we have access to

  11. Laparoendoscopic rendezvous may be an effective alternative to a failed preoperative endoscopic retrograde cholangiopancreatography in patients with cholecystocholedocholithiasis.

    Science.gov (United States)

    Tsiopoulos, Fotios; Kapsoritakis, Andreas; Psychos, Athanassios; Manolakis, Anastasios; Oikonomou, Konstantinos; Tzovaras, George; Baloyiannis, Ioannis; Tsikrika, Alexandra; Potamianos, Spyros

    2018-01-01

    Endoscopic retrograde cholangiopancreatography (ERCP), followed by laparoscopic cholecystectomy (LC), remains the standard way of management for patients with cholecystocholedocholithiasis. Laparoendoscopic rendezvous (LERV), a combined procedure for removing the gallbladder laparoscopically and clearing the common bile duct (CBD) endoscopically at the same time, could be an attractive alternative. The aim of this study was to compare LERV with classic ERCP in patients with cholecystocholedocholithiasis. 886 patients with cholecystocholedocholithiasis were treated either with the LERV technique (90 patients), or with the 2-stage approach, which includes preoperative ERCP followed by LC (796 patients). The primary endpoint was any difference in the success of CBD cannulation and clearance; secondary endpoints were the detection of differences in morbidity (especially post-ERCP pancreatitis [PEP]), and the feasibility of the two approaches. Successful cannulation of the CBD was more frequent with conventional ERCP compared with the LERV technique (89.8% vs. 75.5%, P=0.0001). LERV appears to be as effective as conventional ERCP for complete CBD clearance (85.5% vs. 82.8%, P<0.1). None of the patients in the LERV group had an episode of clinical PEP, whereas in the conventional ERCP group there were 23 episodes of PEP and one death. The median amylase level was higher in patients undergoing conventional ERCP group compared to patients in LERV group. Classic ERCP has a higher rate of successful CBD cannulation and a similar rate of CBD clearance compared to LERV.

  12. Single-site Lennard-Jones models via polynomial chaos surrogates of Monte Carlo molecular simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kadoura, Ahmad, E-mail: ahmad.kadoura@kaust.edu.sa, E-mail: adil.siripatana@kaust.edu.sa, E-mail: shuyu.sun@kaust.edu.sa, E-mail: omar.knio@kaust.edu.sa; Sun, Shuyu, E-mail: ahmad.kadoura@kaust.edu.sa, E-mail: adil.siripatana@kaust.edu.sa, E-mail: shuyu.sun@kaust.edu.sa, E-mail: omar.knio@kaust.edu.sa [Computational Transport Phenomena Laboratory, The Earth Sciences and Engineering Department, The Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia); Siripatana, Adil, E-mail: ahmad.kadoura@kaust.edu.sa, E-mail: adil.siripatana@kaust.edu.sa, E-mail: shuyu.sun@kaust.edu.sa, E-mail: omar.knio@kaust.edu.sa; Hoteit, Ibrahim, E-mail: ibrahim.hoteit@kaust.edu.sa [Earth Fluid Modeling and Predicting Group, The Earth Sciences and Engineering Department, The Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia); Knio, Omar, E-mail: ahmad.kadoura@kaust.edu.sa, E-mail: adil.siripatana@kaust.edu.sa, E-mail: shuyu.sun@kaust.edu.sa, E-mail: omar.knio@kaust.edu.sa [Uncertainty Quantification Center, The Applied Mathematics and Computational Science Department, The Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia)

    2016-06-07

    In this work, two Polynomial Chaos (PC) surrogates were generated to reproduce Monte Carlo (MC) molecular simulation results of the canonical (single-phase) and the NVT-Gibbs (two-phase) ensembles for a system of normalized structureless Lennard-Jones (LJ) particles. The main advantage of such surrogates, once generated, is the capability of accurately computing the needed thermodynamic quantities in a few seconds, thus efficiently replacing the computationally expensive MC molecular simulations. Benefiting from the tremendous computational time reduction, the PC surrogates were used to conduct large-scale optimization in order to propose single-site LJ models for several simple molecules. Experimental data, a set of supercritical isotherms, and part of the two-phase envelope, of several pure components were used for tuning the LJ parameters (ε, σ). Based on the conducted optimization, excellent fit was obtained for different noble gases (Ar, Kr, and Xe) and other small molecules (CH{sub 4}, N{sub 2}, and CO). On the other hand, due to the simplicity of the LJ model used, dramatic deviations between simulation and experimental data were observed, especially in the two-phase region, for more complex molecules such as CO{sub 2} and C{sub 2} H{sub 6}.

  13. Induction of prophage lambda by chlorinated organics: Detection of some single-species/single-site carcinogens

    Energy Technology Data Exchange (ETDEWEB)

    DeMarini, D.M.; Brooks, H.G. (Environmental Protection Agency, Research Triangle Park, NC (United States))

    1992-01-01

    Twenty-eight chlorinated organic compounds were evaluated for their ability to induce DNA damage using the Microscreen prophage-induction assay in Escherichia coli. Comparison of the performance characteristics of the prophage-induction and Salmonella assays to rodent carcinogenicity assays showed that the prophage-induction assay had a somewhat higher specificity than did the Salmonella assay (70% vs. 50%); sensitivity, concordance, and positive and negative predictivity were similar for the two microbial assays. The Microscreen prophage-induction assay failed to detect eight carcinogens, perhaps due to toxicity or other unknown factors; five of these eight carcinogens were detected by the Salmonella assay. However, the prophage-induction assay did detect six carcinogens that were not detected by the Salmonella assay, and five of these were single-species, single-site carcinogens, mostly mouse liver carcinogens. Some of these carcinogens, such as the chloroethanes, produce free radicals, which may be the basis for their carcinogenicity and ability to induce prophage. The prophage-induction (or other SOS) assay may be useful in identifying some genotoxic chlorinated carcinogens that induce DNA damage that do not revert the standard Salmonella tester strains.

  14. Hanford Site Welding Program Successfully Providing A Single Site Function For Use By Multiple Contractors

    International Nuclear Information System (INIS)

    Cannell, G.R.

    2009-01-01

    The Department of Energy, Richland Operations (DOE-RL) recently restructured its Hanford work scope, awarding two new contracts over the past several months for a total of three contracts to manage the sites cleanup efforts. DOE-RL met with key contractor personnel prior to and during contract transition to ensure site welding activities had appropriate oversight and maintained code compliance. The transition also provided an opportunity to establish a single site-wide function that would provide welding and materials engineering services to the Hanford site contractors: CH2M HILL Plateau Remediation Company (CHPRC); Mission Support Alliance (MSA); Washington River Protection Solutions (WRPS); and Washington Closure Hanford (WCH). Over the years, multiple and separate welding programs (amongst the several contractors) existed at the Hanford site leading to inefficiencies resulting from duplication of administrative efforts, maintenance of welding procedures, welder performance certifications, etc. The new, single program eliminates these inefficiencies. The new program, co-managed by two of the sites' new contractors, the CHPRC ('owner' of the program and responsible for construction welding services) and the MSA (provides maintenance welding services), provides more than just the traditional construction and maintenance welding services. Also provided, are welding engineering, specialty welding development/qualification for the closure of radioactive materials containers and materials evaluation/failure analysis. The following describes the new Hanford site welding program.

  15. Single-site Green function of the Dirac equation for full-potential electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Kordt, Pascal

    2012-05-30

    I present an elaborated analytical examination of the Green function of an electron scattered at a single-site potential, for both the Schroedinger and the Dirac equation, followed by an efficient numerical solution, in both cases for potentials of arbitrary shape without an atomic sphere approximation. A numerically stable way to calculate the corresponding regular and irregular wave functions and the Green function is via the angular Lippmann-Schwinger integral equations. These are solved based on an expansion in Chebyshev polynomials and their recursion relations, allowing to rewrite the Lippmann-Schwinger equations into a system of algebraic linear equations. Gonzales et al. developed this method for the Schroedinger equation, where it gives a much higher accuracy compared to previous perturbation methods, with only modest increase in computational effort. In order to apply it to the Dirac equation, I developed relativistic Lippmann-Schwinger equations, based on a decomposition of the potential matrix into spin spherical harmonics, exploiting certain properties of this matrix. The resulting method was embedded into a Korringa-Kohn-Rostoker code for density functional calculations. As an example, the method is applied by calculating phase shifts and the Mott scattering of a tungsten impurity. (orig.)

  16. Single-site Green function of the Dirac equation for full-potential electron scattering

    International Nuclear Information System (INIS)

    Kordt, Pascal

    2012-01-01

    I present an elaborated analytical examination of the Green function of an electron scattered at a single-site potential, for both the Schroedinger and the Dirac equation, followed by an efficient numerical solution, in both cases for potentials of arbitrary shape without an atomic sphere approximation. A numerically stable way to calculate the corresponding regular and irregular wave functions and the Green function is via the angular Lippmann-Schwinger integral equations. These are solved based on an expansion in Chebyshev polynomials and their recursion relations, allowing to rewrite the Lippmann-Schwinger equations into a system of algebraic linear equations. Gonzales et al. developed this method for the Schroedinger equation, where it gives a much higher accuracy compared to previous perturbation methods, with only modest increase in computational effort. In order to apply it to the Dirac equation, I developed relativistic Lippmann-Schwinger equations, based on a decomposition of the potential matrix into spin spherical harmonics, exploiting certain properties of this matrix. The resulting method was embedded into a Korringa-Kohn-Rostoker code for density functional calculations. As an example, the method is applied by calculating phase shifts and the Mott scattering of a tungsten impurity. (orig.)

  17. Evidence that adaptation in Drosophila is not limited by mutation at single sites.

    Directory of Open Access Journals (Sweden)

    Talia Karasov

    2010-06-01

    Full Text Available Adaptation in eukaryotes is generally assumed to be mutation-limited because of small effective population sizes. This view is difficult to reconcile, however, with the observation that adaptation to anthropogenic changes, such as the introduction of pesticides, can occur very rapidly. Here we investigate adaptation at a key insecticide resistance locus (Ace in Drosophila melanogaster and show that multiple simple and complex resistance alleles evolved quickly and repeatedly within individual populations. Our results imply that the current effective population size of modern D. melanogaster populations is likely to be substantially larger (> or = 100-fold than commonly believed. This discrepancy arises because estimates of the effective population size are generally derived from levels of standing variation and thus reveal long-term population dynamics dominated by sharp--even if infrequent--bottlenecks. The short-term effective population sizes relevant for strong adaptation, on the other hand, might be much closer to census population sizes. Adaptation in Drosophila may therefore not be limited by waiting for mutations at single sites, and complex adaptive alleles can be generated quickly without fixation of intermediate states. Adaptive events should also commonly involve the simultaneous rise in frequency of independently generated adaptive mutations. These so-called soft sweeps have very distinct effects on the linked neutral polymorphisms compared to the standard hard sweeps in mutation-limited scenarios. Methods for the mapping of adaptive mutations or association mapping of evolutionarily relevant mutations may thus need to be reconsidered.

  18. Single-site Lennard-Jones models via polynomial chaos surrogates of Monte Carlo molecular simulation

    KAUST Repository

    Kadoura, Ahmad Salim

    2016-06-01

    In this work, two Polynomial Chaos (PC) surrogates were generated to reproduce Monte Carlo (MC) molecular simulation results of the canonical (single-phase) and the NVT-Gibbs (two-phase) ensembles for a system of normalized structureless Lennard-Jones (LJ) particles. The main advantage of such surrogates, once generated, is the capability of accurately computing the needed thermodynamic quantities in a few seconds, thus efficiently replacing the computationally expensive MC molecular simulations. Benefiting from the tremendous computational time reduction, the PC surrogates were used to conduct large-scale optimization in order to propose single-site LJ models for several simple molecules. Experimental data, a set of supercritical isotherms, and part of the two-phase envelope, of several pure components were used for tuning the LJ parameters (ε, σ). Based on the conducted optimization, excellent fit was obtained for different noble gases (Ar, Kr, and Xe) and other small molecules (CH4, N2, and CO). On the other hand, due to the simplicity of the LJ model used, dramatic deviations between simulation and experimental data were observed, especially in the two-phase region, for more complex molecules such as CO2 and C2 H6.

  19. Single-site SBA-15 supported zirconium catalysts. Synthesis, characterization and toward cyanosilylation reaction

    Science.gov (United States)

    Xu, Wei; Yu, Bo; Zhang, Ying; Chen, Xi; Zhang, Guofang; Gao, Ziwei

    2015-01-01

    A successive anchoring of Zr(NMe2)4, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1‧-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on dehydroxylated SBA-15 pretreated at 500 °C for 16 h (SBA-15-500) was conducted by SOMC strategy in moderate conditions. The dehydoxylation of SBA-15 was monitored by in situ Fourier transform infrared spectroscopy (in situ FT-IR). The ligand-modified SBA-15-500 supported zirconium complexes were characterized by in situ FT-IR, 13C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MAS) and elemental analysis in detail, verifying that the surface zirconium species are single-sited. The catalytic activity of these complexes was evaluated by cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the structure of surface species and the configuration of the ligands.

  20. The concept, reality and utility of single-site heterogeneous catalysts (SSHCs).

    Science.gov (United States)

    Thomas, John Meurig

    2014-05-07

    Very substantial advances have recently been made in the design and construction of solid catalysts and in elucidating both their mode of operation and the factors that determine their selectivity and longevity. This Perspective explains how and why such progress has been made. One important factor, the deployment of single-site heterogeneous and enzymatic catalysts, used either alone or in conjunction with other strategies, including metabolic engineering, enables a multitude of new products (for example, environmentally clean jet fuel) to be readily manufactured. In a practical sense SSHCs enable the advantages of homogeneous and to a lesser degree enzymatic catalysts to be united with those of heterogeneous ones. With the aid of the vastly increasing families of nanoporous solids, desired catalytically active sites may be engineered in atomic detail on their inner, accessible surfaces, thereby opening up new possibilities in synthetic organic chemistry - as in the smooth formation of C-C and C[double bond, length as m-dash]N bonds in a number of intermolecular reactions - as well as in photocatalysts and in fluidized catalytic cracking of hydrocarbons.

  1. Individual single-site travel cost model for Czech paradise geopark

    Directory of Open Access Journals (Sweden)

    Jan Špaček

    2013-01-01

    Full Text Available Geotourism is a new phenomenon, which has emerged in the tourism literature during the past two decades, and whose meaning suffered from global census. Geotourism is still a new discipline and relatively little has been written about its demand side, demonstrated by a lack of studies in the literature This article studies the recreational value of geotourism areas, and focuses on the first geopark in the Czech Republic, namely the Czech Paradise Geopark. To assess the recreational value the travel cost method is applied, specifically the individual travel cost model. The necessary research data was gathered through intensive tourist surveys conducted in the study area. Data gathered in the respondents’ survey served to determine the consumer surplus as a measure of recreational value and to develop the single site travel cost model. The dependent variable in the conducted model is the number of visits in the area and among the independent variables, studied age, education, travel cost, family status, economic activity and income. The results were subsequently compared to findings in the available literature, research works and case studies.

  2. Screened Coulomb interactions in metallic alloys. II. Screening beyond the single-site and atomic-sphere approximations

    DEFF Research Database (Denmark)

    Ruban, Andrei; Simak, S.I.; Korzhavyi, P.A.

    2002-01-01

    -electron potential and energy. In the case of a random alloy such interactions can be accounted for only by lifting the atomic-sphere and single-site approximations, in order to include the polarization due to local environment effects. Nevertheless, a simple parametrization of the screened Coulomb interactions...... for the ordinary single-site methods, including the generalized perturbation method, is still possible. We obtained such a parametrization for bulk and surface NiPt alloys, which allows one to obtain quantitatively accurate effective interactions in this system....

  3. Electrocatalytic Water Oxidation by a Homogeneous Copper Catalyst Disfavors Single-Site Mechanisms.

    Science.gov (United States)

    Koepke, Sara J; Light, Kenneth M; VanNatta, Peter E; Wiley, Keaton M; Kieber-Emmons, Matthew T

    2017-06-28

    Deployment of solar fuels derived from water requires robust oxygen-evolving catalysts made from earth abundant materials. Copper has recently received much attention in this regard. Mechanistic parallels between Cu and single-site Ru/Ir/Mn water oxidation catalysts, including intermediacy of terminal Cu oxo/oxyl species, are prevalent in the literature; however, intermediacy of late transition metal oxo species would be remarkable given the high d-electron count would fill antibonding orbitals, making these species high in energy. This may suggest alternate pathways are at work in copper-based water oxidation. This report characterizes a dinuclear copper water oxidation catalyst, {[(L)Cu(II)] 2 -(μ-OH) 2 }(OTf) 2 (L = Me 2 TMPA = bis((6-methyl-2-pyridyl)methyl)(2-pyridylmethyl)amine) in which water oxidation proceeds with high Faradaic efficiency (>90%) and moderate rates (33 s -1 at ∼1 V overpotential, pH 12.5). A large kinetic isotope effect (k H /k D = 20) suggests proton coupled electron transfer in the initial oxidation as the rate-determining step. This species partially dissociates in aqueous solution at pH 12.5 to generate a mononuclear {[(L)Cu(II)(OH)]} + adduct (K eq = 0.0041). Calculations that reproduce the experimental findings reveal that oxidation of either the mononuclear or dinuclear species results in a common dinuclear intermediate, {[LCu(III)] 2 -(μ-O) 2 } 2+ , which avoids formation of terminal Cu(IV)═O/Cu(III)-O • intermediates. Calculations further reveal that both intermolecular water nucleophilic attack and redox isomerization of {[LCu(III)] 2 -(μ-O) 2 } 2+ are energetically accessible pathways for O-O bond formation. The consequences of these findings are discussed in relation to differences in water oxidation pathways between Cu catalysts and catalysts based on Ru, Ir, and Mn.

  4. Single-site properties of U impurities doped in La2Zn17 (abstract)

    Science.gov (United States)

    Suzuki, H.; Anzai, K.; Takagi, S.

    1997-04-01

    Thermodynamic and transport properties of heavy Fermion (HF) U compounds show similar behavior to HF Ce compounds. Although most of the magnetic properties of HF Ce compounds can be qualitatively understood on the basis of the impurity Kondo model, no such consensus for HF U compounds has been reached. In addition to this, the single-site properties of U impurities are not understood so well, in contrast to the case of Ce impurities. Recent works for dilute U systems reported new features as are not seen in dilute Ce systems. We have investigated a dilute-U2Zn17 system of (La1-zUz)2Zn17 in order to reveal the single U ion site properties of this system by preparing single crystals. The impurity contributions to various physical quantities such as ρimp(T), χimp(T), and Cimp(T) can be scaled by the U concentration between z=0.025 and 0.05, and the system is considered as in the dilute limit still for z=0.05. The electrical resistivity shows the typical impurity-Kondo upturn at low temperatures. The electronic specific-heat coefficient is strongly enhanced (γimp≈1.5 J/K2 mole U) and about 4 times as large as that for dense U2Zn17. Suppressions of the Kondo effect by the magnetic field are seen in γimp(H) and magnetoresistance. The relatively large anisotropy in χimp(T) indicates an existence of the crystal field. These features of this system will be explained in terms of the Kondo effect in the presence of the crystal field.

  5. Single-site robotic cholecystectomy and robotics training: should we start in the junior years?

    Science.gov (United States)

    Ayabe, Reed I; Parrish, Aaron B; Dauphine, Christine E; Hari, Danielle M; Ozao-Choy, Junko J

    2018-04-01

    It has become increasingly important to expose surgical residents to robotic surgery as its applications continue to expand. Single-site robotic cholecystectomy (SSRC) is an excellent introductory case to robotics. Resident involvement in SSRC is known to be feasible. Here, we sought to determine whether it is safe to introduce SSRC to junior residents. A total of 98 SSRC cases were performed by general surgery residents between August 2015 and August 2016. Cases were divided into groups based on resident level: second- and third-years (juniors) versus fourth- and fifth-years (seniors). Patient age, gender, race, body mass index, and comorbidities were recorded. The number of prior laparoscopic cholecystectomies completed by participating residents was noted. Outcomes including operative time, console time, rate of conversion to open cholecystectomy, and complication rate were compared between groups. Juniors performed 54 SSRC cases, whereas seniors performed 44. There were no significant differences in patient age, gender, race, body mass index, or comorbidities between the two groups. Juniors had less experience with laparoscopic cholecystectomy. There was no significant difference in mean operative time (92.7 min versus 98.0 min, P = 0.254), console time (48.7 min versus 50.8 min, P = 0.639), or complication rate (3.7% versus 2.3%, P = 0.68) between juniors and seniors. SSRC is an excellent way to introduce general surgery residents to robotics. This study shows that with attending supervision, SSRC is feasible and safe for both junior and senior residents with very low complication rates and no adverse effect on operative time. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Well-Defined Silica Supported Aluminum Hydride: Another Step Towards the Utopian Single Site Dream?

    KAUST Repository

    Werghi, Baraa; Bendjeriou-Sedjerari, Anissa; Sofack-Kreutzer, Julien; Jedidi, Abdesslem; Abou-Hamad, Edy; Cavallo, Luigi; Basset, Jean-Marie

    2015-01-01

    Reaction of triisobutylaluminum with SBA15700 at room temperature occurs by two parallel pathways involving either silanol or siloxane bridges. It leads to the formation of a well-defined bipodal [(≡SiO)2Al-CH2CH(CH3)2] 1a, silicon isobutyl [≡Si-CH2CH(CH3)2] 1b and a silicon hydride [≡Si-H] 1c. Their structural identity was characterized by FT-IR and advance solid-state NMR spectroscopies (1H, 13C, 29Si, 27Al and 2D multiple quantum), elemental and gas phase analysis, and DFT calculations. The reaction involves the formation of a highly reactive monopodal intermediate: [≡SiO-Al-[CH2CH(CH3)2]2], with evolution of isobutane. This intermediate undergoes two parallel routes: Transfer of either one isobutyl fragment or of one hydride to an adjacent silicon atom. Both processes occur by opening of a strained siloxane bridge, ≡Si-O-Si≡ but with two different mechanisms, showing that the reality of “single site” catalyst may be an utopia: DFT calculations indicate that isobutyl transfer occurs via a simple metathesis between the Al-isobutyl and O-Si bonds, while hydride transfer occurs via a two steps mechanism, the first one is a ß-H elimination to Al with elimination of isobutene, whereas the second is a metathesis step between the formed Al-H bond and a O-Si bond. Thermal treatment of 1a (at 250 °C) under high vacuum (10-5 mbar) generates Al-H through a ß-H elimination of isobutyl fragment. These supported well-defined Al-H which are highly stable with time, are tetra, penta and octa coordinated as demonstrated by IR and 27Al–1H J-HMQC NMR spectroscopy. All these observations indicate that surfaces atoms around the site of grafting play a considerable role in the reactivity of a single site system.

  7. Well-Defined Silica Supported Aluminum Hydride: Another Step Towards the Utopian Single Site Dream?

    KAUST Repository

    Werghi, Baraa

    2015-07-17

    Reaction of triisobutylaluminum with SBA15700 at room temperature occurs by two parallel pathways involving either silanol or siloxane bridges. It leads to the formation of a well-defined bipodal [(≡SiO)2Al-CH2CH(CH3)2] 1a, silicon isobutyl [≡Si-CH2CH(CH3)2] 1b and a silicon hydride [≡Si-H] 1c. Their structural identity was characterized by FT-IR and advance solid-state NMR spectroscopies (1H, 13C, 29Si, 27Al and 2D multiple quantum), elemental and gas phase analysis, and DFT calculations. The reaction involves the formation of a highly reactive monopodal intermediate: [≡SiO-Al-[CH2CH(CH3)2]2], with evolution of isobutane. This intermediate undergoes two parallel routes: Transfer of either one isobutyl fragment or of one hydride to an adjacent silicon atom. Both processes occur by opening of a strained siloxane bridge, ≡Si-O-Si≡ but with two different mechanisms, showing that the reality of “single site” catalyst may be an utopia: DFT calculations indicate that isobutyl transfer occurs via a simple metathesis between the Al-isobutyl and O-Si bonds, while hydride transfer occurs via a two steps mechanism, the first one is a ß-H elimination to Al with elimination of isobutene, whereas the second is a metathesis step between the formed Al-H bond and a O-Si bond. Thermal treatment of 1a (at 250 °C) under high vacuum (10-5 mbar) generates Al-H through a ß-H elimination of isobutyl fragment. These supported well-defined Al-H which are highly stable with time, are tetra, penta and octa coordinated as demonstrated by IR and 27Al–1H J-HMQC NMR spectroscopy. All these observations indicate that surfaces atoms around the site of grafting play a considerable role in the reactivity of a single site system.

  8. Single-site community consultation for emergency research in a community hospital setting.

    Science.gov (United States)

    Galbraith, Kyle L; Keck, Anna-Sigrid; Little, Charletta

    2014-01-01

    The purpose of this study was to evaluate community member feedback from community consultation and public disclosure activities performed for a clinical investigation involving a device designed to treat traumatic brain injury in prehospital contexts. The clinical investigation of that device was to be performed under the federal regulations providing an exception from prospective informed consent requirements in emergency settings. Secondarily, we sought to assess the community consultation process by measuring the levels of outreach provided by the different communication methods used in these activities, with special attention to the effectiveness of social media for community outreach. The medical device investigation consists of a single-site pilot study based at a 345-bed community hospital in east central Illinois, which also serves as the area's only level I trauma center. Investigators, in collaboration with the local institutional review board, fulfilled community consultation and public disclosure requirements through four public town hall meetings, seven targeted focus groups, targeted mailings to 884 community leaders and researchers, a press conference and press release, internal and external websites, and multiple postings to the hospital's Facebook and Twitter accounts. Community members provided feedback by completing paper or electronic comment cards. A total of 428 community members attended the four town hall meetings and seven focus group sessions. Attendance at each meeting ranged from 4 to 20 attendees for the town hall meetings and 8 to 140 attendees for the focus groups. The investigation's external website received 626 unique visitors and the intranet website received 528 unique visits. Social media postings on Facebook and Twitter received six comments and eight "likes" to indicate that an individual read the posting. In total, attendees completed 175 comment cards to provide their feedback. Community member attitudes regarding the

  9. Real-Time Visualization of Active Species in a Single-Site Metal–Organic Framework Photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Sizhuo [Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States; Pattengale, Brian [Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States; Lee, Sungsik [X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60349, United States; Huang, Jier [Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States

    2018-02-06

    In this work, we report a new single-site photocatalyst (Co-Ru-UIO- 67(bpy)) based on a metal-organic framework platform with incorporated molecular photosensitizer and catalyst. We show that this catalyst not only demonstrates exceptional activity for light-driven H2 production but also can be recycled without loss of activity. Using the combination of optical transient absorption spectroscopy and in situ X-ray absorption spectroscopy, we not only captured the key CoI intermediate species formed after ultrafast charge transfer from the incorporated photosensitizer but also identified the rate-limiting step in the catalytic cycle, providing insight into the catalysis mechanism of these single-site metal-organic framework photocatalysts.

  10. Therapeutic benefits of carbon dioxide (CO2) laser on single-site HPV lesions in the lower female genital tract

    Science.gov (United States)

    Urru, Giovanni; Moretti, Gianfranco

    1998-01-01

    Numerous studies have shown contradictory variable percentages of recurrent HPV lesions, after various therapies. The present study therefore evaluates the effectiveness of CO2 laser vaporization in the treatment of single-site HPV lesions of the lower female genital tract in order to confirm the conviction that physical therapy alone, in agreement with some findings reported in the literature, is capable of guaranteeing a high cure rate in selected patients. From January 1995 to June 1996, seventy- five female patients were treated with CO2 laser vaporization for single-site genital HPV lesions, some of which were associated with low-grade intra-epithelial neoplasia. The success rate after 12 months proved to be 97%. The pre-existing clinical symptoms disappeared in all the patients treated. No complication in the vaporization procedure was encountered.

  11. The effect of driving force on intramolecular electron transfer in proteins. Studies on single-site mutated azurins

    DEFF Research Database (Denmark)

    Farver, O; Skov, L K; van de Kamp, M

    1992-01-01

    -6972]. To further investigate the nature of this long-range electron transfer (LRET) proceeding within the protein matrix, we have now investigated it in two azurins where amino acids have been substituted by single-site mutation of the wild-type Pseudomonas aeruginosa azurin. In one mutated protein, a methionine...... the reorganization energy, lambda and electronic coupling factor, beta. The calculated values fit very well with a through-bond LRET mechanism....

  12. Robotic single-access splenectomy using the Da Vinci Single-Site® platform: a case report.

    Science.gov (United States)

    Corcione, Francesco; Bracale, Umberto; Pirozzi, Felice; Cuccurullo, Diego; Angelini, Pier Luigi

    2014-03-01

    Single-access laparoscopic splenectomy can offer patients some advantages. It has many difficulties, such as instrument clashing, lack of triangulation, odd angles and lack of space. The Da Vinci Single-Site® robotic surgery platform could decrease these difficulties. We present a case of single-access robotic splenectomy using this device. A 37 year-old female with idiopathic thrombocytopenic purpura was operated on with a single-site approach, using the Da Vinci Single-Site robotic surgery device. The procedure was successfully completed in 140 min. No intraoperative and postoperative complications occurred. The patient was discharged from hospital on day 3. Single-access robotic splenectomy seems to be feasible and safe using the new robotic single-access platform, which seems to overcome certain limits of previous robotic or conventional single-access laparoscopy. We think that additional studies should also be performed to explore the real cost-effectiveness of the platform. Copyright © 2013 John Wiley & Sons, Ltd.

  13. Open and laparo-endoscopic repair of incarcerated abdominal wall hernias by the use of biological and biosynthetic meshes

    Directory of Open Access Journals (Sweden)

    René H Fortelny

    2016-02-01

    Full Text Available Introduction: Although recently published guidelines recommend against the use of synthetic non-absorbable materials in cases of potentially contaminated or contaminated surgical fields due to the increased risk of infection [1, 2], the use of bio-prosthetic meshes for abdominal wall or ventral hernia repair is still controversially discussed in such cases. Bio-prosthetic meshes have been recommended due to less susceptibility for infection and the decreased risk of subsequent mesh explantation. The purpose of this review is to elucidate if there are any indications for the use of biological and biosynthetic meshes in incarcerated abdominal wall hernias based on the recently published literature.Methods: A literature search of the Medline database using the PubMed search engine, using the keywords returned 486 articles up to June 2015. The full text of 486 articles was assessed and 13 relevant papers were identified including 5 retrospective case cohort studies, 2 case controlled studies, 6 case series.Results: The results of Franklin et al [23, 24, 25] included the highest number of biological mesh repairs (Surgisis® by laparoscopic IPOM in infected fields which demonstrated a very low incidence of infection and recurrence (0,7% and 5,2%. Han et al [26] reported in his retrospective study the highest number of treated patients due to incarcerated hernias by open approach using acellular dermal matrix (ADM® with very low rate of infection as well as recurrences (1,6% and 15,9. Both studies achieved acceptable outcome in a follow up of at least 3,5 years compared to the use of synthetic mesh in this high-risk population [3]Conclusion:Currently there is a very limited evidence for the use of biological and biosynthetic meshes in strangulated hernias in either open or laparo-endoscopic repair. Finally, there is an urgent need to start with randomized controlled comparative trials as well as to support registries with data to achieve more

  14. Diagnostic Laparoscopy as Decision Tool for Re-recurrent Inguinal Hernia Treatment Following Open Anterior and Laparo-Endoscopic Posterior Repair

    Directory of Open Access Journals (Sweden)

    Ferdinand Köckerling

    2017-05-01

    Full Text Available IntroductionThe guidelines of the international hernia societies recommend posterior repair in laparo-endoscopic technique for recurrent inguinal hernia after open anterior mesh repair and, conversely, open anterior repair for recurrence after laparo-endoscopic primary repair. Even when these guidelines are followed, already 1 year after repair a re-recurrence rate of 1–2% must be expected, with that rate rising further in the subsequent years. Accordingly, increasingly more patients with re-recurrence after anterior and posterior mesh implantation must be treated, which constitutes a problem that to date has been investigated in only very few studies. Hence, there are no well-founded recommendations. This paper now presents a number of case reports aimed at identifying the role of explorative laparoscopy as decision tool for re-recurrent inguinal hernia treatment.Patients and methodsBased on three case reports the role of explorative laparoscopy as decision tool for re-recurrent inguinal hernia treatment is presented below.ResultsIn all the three cases described explorative laparoscopy played a key role as decision tool when deciding how best to treat re-recurrence after anterior and posterior inguinal hernia repair. In one case severe adhesions after robotic prostatectomy and in another case correct placement of the mesh in the posterior plane, adhesions from the cecum to the groin region and no definitive finding of a re-recurrence resulted in an open repair. In the third case, an insufficient laparoscopic posterior mesh placement made the re-recurrent TAPP procedure relatively easy.ConclusionExplorative laparoscopy is an important decision tool for re-recurrent inguinal hernia treatment to minimize the risks of the procedure for the patients.

  15. Hybrid Nanomaterials with Single-Site Catalysts by Spatially Controllable Immobilization of Nickel Complexes via Photoclick Chemistry for Alkene Epoxidation.

    Science.gov (United States)

    Ghosh, Dwaipayan; Febriansyah, Benny; Gupta, Disha; Ng, Leonard Kia-Sheun; Xi, Shibo; Du, Yonghua; Baikie, Tom; Dong, ZhiLi; Soo, Han Sen

    2018-05-22

    Catalyst deactivation is a persistent problem not only for the scientific community but also in industry. Isolated single-site heterogeneous catalysts have shown great promise to overcome these problems. Here, a versatile anchoring strategy for molecular complex immobilization on a broad range of semiconducting or insulating metal oxide ( e. g., titanium dioxide, mesoporous silica, cerium oxide, and tungsten oxide) nanoparticles to synthesize isolated single-site catalysts has been studied systematically. An oxidatively stable anchoring group, maleimide, is shown to form covalent linkages with surface hydroxyl functionalities of metal oxide nanoparticles by photoclick chemistry. The nanocomposites have been thoroughly characterized by techniques including UV-visible diffuse reflectance spectroscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, and X-ray absorption spectroscopy (XAS). The IR spectroscopic studies confirm the covalent linkages between the maleimide group and surface hydroxyl functionalities of the oxide nanoparticles. The hybrid nanomaterials function as highly efficient catalysts for essentially quantitative oxidations of terminal and internal alkenes and show molecular catalyst product selectivities even in more eco-friendly solvents. XAS studies verify the robustness of the catalysts after several catalytic cycles. We have applied the photoclick anchoring methodology to precisely control the deposition of a luminescent variant of our catalyst on the metal oxide nanoparticles. Overall, we demonstrate a general approach to use irradiation to anchor molecular complexes on oxide nanoparticles to create recyclable, hybrid, single-site catalysts that function with high selectivity in a broad range of solvents. We have achieved a facile, spatially and temporally controllable photoclick method that can potentially be extended to other ligands, catalysts, functional molecules, and surfaces.

  16. Isospecific propylene polymerization with in situ generated bis(phenoxy-amine)zirconium and hafnium single site catalysts.

    Science.gov (United States)

    Makio, Haruyuki; Prasad, Aitha Vishwa; Terao, Hiroshi; Saito, Junji; Fujita, Terunori

    2013-07-07

    Bis(phenoxy-imine) Zr and Hf complexes were activated with (i)Bu3Al or (i)Bu2AlH in conjunction with Ph3CB(C6F5)4 and tested as catalysts for propylene polymerization with emphasis on the enantioselectivity of the isospecific species and the single site polymerization characteristics. The isoselective species was identified as the in situ generated bis(phenoxy-amine) complex whose isoselectivity was sensitive to subtle changes in ligand structure. By employing specific substituents at certain key positions the isotacticity reached an extremely high level comparable to high-end commercial isotactic polypropylenes (Tm > 160 °C). Single site polymerization characteristics depended upon the efficiency and selectivity of the in situ imine reduction which is sensitive to the substituent on the imine nitrogen and the reaction conditions. By using (i)Bu2AlH as a reducing agent, quantitative imine reduction can be achieved with a stoichiometric amount of the reducing agent. This lower alkylaluminum loading is beneficial for the catalyst and significantly enhances the polymerization activity and the molecular weight of the resultant polymer.

  17. Wegner estimate and localization for alloy-type models with sign-changing exponentially decaying single-site potentials

    Science.gov (United States)

    Leonhardt, Karsten; Peyerimhoff, Norbert; Tautenhahn, Martin; Veselić, Ivan

    2015-05-01

    We study Schrödinger operators on L2(ℝd) and ℓ2(ℤd) with a random potential of alloy-type. The single-site potential is assumed to be exponentially decaying but not necessarily of fixed sign. In the continuum setting, we require a generalized step-function shape. Wegner estimates are bounds on the average number of eigenvalues in an energy interval of finite box restrictions of these types of operators. In the described situation, a Wegner estimate, which is polynomial in the volume of the box and linear in the size of the energy interval, holds. We apply the established Wegner estimate as an ingredient for a localization proof via multiscale analysis.

  18. Single-Site Active Iron-Based Bifunctional Oxygen Catalyst for a Compressible and Rechargeable Zinc-Air Battery.

    Science.gov (United States)

    Ma, Longtao; Chen, Shengmei; Pei, Zengxia; Huang, Yan; Liang, Guojin; Mo, Funian; Yang, Qi; Su, Jun; Gao, Yihua; Zapien, Juan Antonio; Zhi, Chunyi

    2018-02-27

    The exploitation of a high-efficient, low-cost, and stable non-noble-metal-based catalyst with oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) simultaneously, as air electrode material for a rechargeable zinc-air battery is significantly crucial. Meanwhile, the compressible flexibility of a battery is the prerequisite of wearable or/and portable electronics. Herein, we present a strategy via single-site dispersion of an Fe-N x species on a two-dimensional (2D) highly graphitic porous nitrogen-doped carbon layer to implement superior catalytic activity toward ORR/OER (with a half-wave potential of 0.86 V for ORR and an overpotential of 390 mV at 10 mA·cm -2 for OER) in an alkaline medium. Furthermore, an elastic polyacrylamide hydrogel based electrolyte with the capability to retain great elasticity even under a highly corrosive alkaline environment is utilized to develop a solid-state compressible and rechargeable zinc-air battery. The creatively developed battery has a low charge-discharge voltage gap (0.78 V at 5 mA·cm -2 ) and large power density (118 mW·cm -2 ). It could be compressed up to 54% strain and bent up to 90° without charge/discharge performance and output power degradation. Our results reveal that single-site dispersion of catalytic active sites on a porous support for a bifunctional oxygen catalyst as cathode integrating a specially designed elastic electrolyte is a feasible strategy for fabricating efficient compressible and rechargeable zinc-air batteries, which could enlighten the design and development of other functional electronic devices.

  19. Face, content, and construct validity of four, inanimate training exercises using the da Vinci ® Si surgical system configured with Single-Site ™ instrumentation.

    Science.gov (United States)

    Jarc, Anthony M; Curet, Myriam

    2015-08-01

    Validated training exercises are essential tools for surgeons as they develop technical skills to use robot-assisted minimally invasive surgical systems. The purpose of this study was to show face, content, and construct validity of four, inanimate training exercises using the da Vinci (®) Si surgical system configured with Single-Site (™) instrumentation. New (N = 21) and experienced (N = 6) surgeons participated in the study. New surgeons (11 Gynecology [GYN] and 10 General Surgery [GEN]) had not completed any da Vinci Single-Site cases but may have completed multiport cases using the da Vinci system. They participated in this study prior to attending a certification course focused on da Vinci Single-Site instrumentation. Experienced surgeons (5 GYN and 1 GEN) had completed at least 25 da Vinci Single-Site cases. The surgeons completed four inanimate training exercises and then rated them with a questionnaire. Raw metrics and overall normalized scores were computed using both video recordings and kinematic data collected from the surgical system. The experienced surgeons significantly outperformed new surgeons for many raw metrics and the overall normalized scores derived from video review (p da Vinci Single-Site surgery and actually testing the technical skills used during da Vinci Single-Site surgery. In summary, the four training exercises showed face, content, and construct validity. Improved overall scores could be developed using additional metrics not included in this study. The results suggest that the training exercises could be used in an overall training curriculum aimed at developing proficiency in technical skills for surgeons new to da Vinci Single-Site instrumentation.

  20. Society of Laparoendoscopic Surgeons

    Science.gov (United States)

    ... the Minimally Invasive Surgery and Therapy World. Nezhat’s History of Endoscopy In 2005 pioneering surgeon Dr. Camran Nezhat was awarded a fellowship by The American College of Obstetrics and Gynecology to research and write this important ...

  1. Seasonal variation of heavy metals in ambient air and precipitation at a single site in Washington, DC

    International Nuclear Information System (INIS)

    Melaku, Samuel; Morris, Vernon; Raghavan, Dharmaraj; Hosten, Charles

    2008-01-01

    Atmospheric samples of precipitation and ambient air were collected at a single site in Washington, DC, for 7 months (for ambient air samples) and 1 year (for wet deposition samples) and analyzed for arsenic, cadmium, chromium and lead. The ranges of heavy metal concentrations for 6-day wet deposition samples collected over the 1-year period were 0.20-1.3 μg/l, 0.060-5.1 μg/l, 0.062-4.6 μg/l and 0.11-3.2 μg/l for arsenic, cadmium, chromium and lead, respectively, with a precision better than 5% for more than 95% of the measurements. The ranges of heavy metal concentrations for the 6-day ambient air samples were 0.800-15.7 ng/m 3 , 1.50-30.0 ng/m 3 , 16.8-112 ng/m 3 , and 2.90-137 ng/m 3 for arsenic, cadmium, chromium and lead, respectively, with a precision better than 10%. The spread in the heavy metal concentration over the observation period suggests a high seasonal variability for heavy metal content in both ambient air and wet deposition samples. - High seasonal variability of heavy metals were observed in both ambient air and wet deposition samples

  2. Stability of detectability over 17 years at a single site and other lizard detection comparisons from Guam

    Science.gov (United States)

    Rodda, Gordon H.; Dean-Bradley, Kathryn; Campbell, Earl W.; Fritts, Thomas H.; Lardner, Bjorn; Yackel Adams, Amy A.; Reed, Robert N.

    2015-01-01

    To obtain quantitative information about population dynamics from counts of animals, the per capita detectabilities of each species must remain constant over the course of monitoring. We characterized lizard detection constancy for four species over 17 yr from a single site in northern Guam, a relatively benign situation because detection was relatively easy and we were able to hold constant the site, habitat type, species, season, and sampling method. We monitored two species of diurnal terrestrial skinks (Carlia ailanpalai [Curious Skink], Emoia caeruleocauda [Pacific Bluetailed Skink]) using glueboards placed on the ground in the shade for 3 h on rainless mornings, yielding 10,286 skink captures. We additionally monitored two species of nocturnal arboreal geckos (Hemidactylus frenatus [Common House Gecko]; Lepidodactylus lugubris [Mourning Gecko]) on the basis of 15,212 sightings. We compared these count samples to a series of complete censuses we conducted from four or more total removal plots (everything removed to mineral soil) totaling 400 m2(about 1% of study site) in each of the years 1995, 1999, and 2012, providing time-stamped quantification of detectability for each species. Unfortunately, the actual population trajectories taken by the four species were masked by unexplained variation in detectability. This observation of debilitating latent variability in lizard detectability under nearly ideal conditions undercuts our trust in population estimation techniques that fail to quantify venue-specific detectability, rely on pooled detection probability estimates, or assume that modulation in predefined environmental covariates suffices for estimating detectability.

  3. A modified technique reduced operative time of laparoendoscopic rendezvous endoscopic retrograde cholangiopancreatography combined with laparoscopic cholecystectomy for concomitant gallstone and common bile ductal stone.

    Science.gov (United States)

    Liu, Wei; Wang, Qunwei; Xiao, Jing; Zhao, Liying; Huang, Jiangsheng; Tan, Zhaohui; Li, Pengfei

    2014-01-01

    Laparoendoscopic rendezvous (LERV) endoscopic retrograde cholangiopancreatography (ERCP) and laparoscopic cholecystectomy (LC+ERCP/LERV) are considered an optimal approach for concomitant gallstones and common bile duct stones. The rendezvous technique is essential for the success of procedure. We applied two different LERV techniques, traditional technique and modified technique, in 60 consecutive cases from January 2011 to November 2012. 32 cases who underwent modified technique (group 1) from February 2012 to November 2012 were retrospectively compared to 28 cases (group 2) who underwent traditional technique from January 2011 to January 2012. There was no significant difference between two groups with respect to preoperative demographic features. Although the difference was not statistically significant, the procedure was successfully performed in 31 cases (96.9%) in group 1 and 24 cases (86.2%) in group 2. The mean operative time and time of endoscopic part were 82.6 ± 19.6 min and 26.5 ± 5.99 min in group 1 which were significantly shorter than those in group 2 (118.0 ± 23.1 min and 58.7 ± 13.3 min, resp.). There was no postoperative pancreatitis and mortality in both groups. The mean hospital stay, blood loss, incidence of complications, and residual stone were of no difference in both groups. This study proved that this modified technique can effectively reduce the operative time and time of endoscopic part of LC+ERCP/LERV compared with traditional technique.

  4. A Modified Technique Reduced Operative Time of Laparoendoscopic Rendezvous Endoscopic Retrograde Cholangiopancreatography Combined with Laparoscopic Cholecystectomy for Concomitant Gallstone and Common Bile Ductal Stone

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2014-01-01

    Full Text Available Laparoendoscopic rendezvous (LERV endoscopic retrograde cholangiopancreatography (ERCP and laparoscopic cholecystectomy (LC+ERCP/LERV are considered an optimal approach for concomitant gallstones and common bile duct stones. The rendezvous technique is essential for the success of procedure. We applied two different LERV techniques, traditional technique and modified technique, in 60 consecutive cases from January 2011 to November 2012. 32 cases who underwent modified technique (group 1 from February 2012 to November 2012 were retrospectively compared to 28 cases (group 2 who underwent traditional technique from January 2011 to January 2012. There was no significant difference between two groups with respect to preoperative demographic features. Although the difference was not statistically significant, the procedure was successfully performed in 31 cases (96.9% in group 1 and 24 cases (86.2% in group 2. The mean operative time and time of endoscopic part were 82.6 ± 19.6 min and 26.5 ± 5.99 min in group 1 which were significantly shorter than those in group 2 (118.0 ± 23.1 min and 58.7 ± 13.3 min, resp.. There was no postoperative pancreatitis and mortality in both groups. The mean hospital stay, blood loss, incidence of complications, and residual stone were of no difference in both groups. This study proved that this modified technique can effectively reduce the operative time and time of endoscopic part of LC+ERCP/LERV compared with traditional technique.

  5. Randomised study on single stage laparo-endoscopic rendezvous (intra-operative ERCP) procedure versus two stage approach (Pre-operative ERCP followed by laparoscopic cholecystectomy) for the management of cholelithiasis with choledocholithiasis.

    Science.gov (United States)

    Sahoo, Manash Ranjan; Kumar, Anil T; Patnaik, Aashish

    2014-07-01

    The 'Rendezvous' technique consists of laparoscopic cholecystectomy (LC) standards with intra-operative cholangiography followed by endoscopic sphincterotomy. The sphincterotome is driven across the papilla through a guidewire inserted by the transcystic route. In this study, we intended to compare the two methods in a prospective randomised trial. From 2005 to 2012, we enrolled 83 patients with a diagnosis of cholecysto-choledocolithiasis. They were randomised into two groups. In 'group-A',41 patients were treated with two stages management, first by pre-operative endoscopic retrograde cholangiopancreatography (ERCP) and common bile duct (CBD) clearance and second by LC. In 'group-B', 42 patients were treated with LC and intra-operative cholangiography; and when diagnosis of choledocholithiasis was confirmed, patients had undergone one stage management of by Laparo-endoscopic Rendezvous technique. In arm-A and arm-B groups, complete CBD clearance was achieved in 29 and 38 patients, respectively. Failure of the treatment in arm-A was 29% and in arm-B was 9.5%. In arm-A, selective CBD cannulation was achieved in 33 cases (80.5%) and in arm-B in 39 cases (93%). In arm-Agroup, post-ERCP hyperamylasia was presented in nine patients (22%) and severe pancreatitis in five patients (12%) versus none of the patients (0%) in arm-B group, respectively. Mean post-operative hospital stay in arm-A and arm-B groups are 10.9 and 6.8 days, respectively. One stage laparo-endoscopic rendezvous approach increases selective cannulation of CBD, reduces post-ERCP pancreatitis, reduces days of hospital stay, increases patient's compliance and prevents unnecessary intervention to CBD.

  6. Randomised study on single stage laparo-endoscopic rendezvous (intra-operative ERCP procedure versus two stage approach (Pre-operative ERCP followed by laparoscopic cholecystectomy for the management of cholelithiasis with choledocholithiasis

    Directory of Open Access Journals (Sweden)

    Manash Ranjan Sahoo

    2014-01-01

    Full Text Available Introduction : The ′Rendezvous′ technique consists of laparoscopic cholecystectomy (LC standards with intra-operative cholangiography followed by endoscopic sphincterotomy. The sphincterotome is driven across the papilla through a guidewire inserted by the transcystic route. In this study, we intended to compare the two methods in a prospective randomised trial. Materials And Methods: From 2005 to 2012, we enrolled 83 patients with a diagnosis of cholecysto-choledocolithiasis. They were randomised into two groups. In ′group-A′,41 patients were treated with two stages management, first by pre-operative endoscopic retrograde cholangiopancreatography (ERCP and common bile duct (CBD clearance and second by LC. In ′group-B′, 42 patients were treated with LC and intra-operative cholangiography; and when diagnosis of choledocholithiasis was confirmed, patients had undergone one stage management of by Laparo-endoscopic Rendezvous technique. Results: In arm-A and arm-B groups, complete CBD clearance was achieved in 29 and 38 patients, respectively. Failure of the treatment in arm-A was 29% and in arm-B was 9.5%. In arm-A, selective CBD cannulation was achieved in 33 cases (80.5% and in arm-B in 39 cases (93%. In arm-Agroup, post-ERCP hyperamylasia was presented in nine patients (22% and severe pancreatitis in five patients (12% versus none of the patients (0% in arm-B group, respectively. Mean post-operative hospital stay in arm-A and arm-B groups are 10.9 and 6.8 days, respectively. Conclusion: One stage laparo-endoscopic rendezvous approach increases selective cannulation of CBD, reduces post-ERCP pancreatitis, reduces days of hospital stay, increases patient′s compliance and prevents unnecessary intervention to CBD.

  7. Redox-active on-surface polymerization of single-site divalent cations from pure metals by a ketone-functionalized phenanthroline

    Energy Technology Data Exchange (ETDEWEB)

    Skomski, Daniel; Tempas, Christopher D.; Bukowski, Gregory S.; Smith, Kevin A.; Tait, Steven L., E-mail: tait@indiana.edu [Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405 (United States)

    2015-03-14

    Metallic iron, chromium, or platinum mixing with a ketone-functionalized phenanthroline ligand on a single crystal gold surface demonstrates redox activity to a well-defined oxidation state and assembly into thermally stable, one dimensional, polymeric chains. The diverging ligand geometry incorporates redox-active sub-units and bi-dentate binding sites. The gold surface provides a stable adsorption environment and directs growth of the polymeric chains, but is inert with regard to the redox chemistry. These systems are characterized by scanning tunnelling microscopy, non-contact atomic force microscopy, and X-ray photoelectron spectroscopy under ultra-high vacuum conditions. The relative propensity of the metals to interact with the ketone group is examined, and it is found that Fe and Cr more readily complex the ligand than Pt. The formation and stabilization of well-defined transition metal single-sites at surfaces may open new routes to achieve higher selectivity in heterogeneous catalysts.

  8. Enhancement of Ag-Based Plasmonic Photocatalysis in Hydrogen Production from Ammonia Borane by the Assistance of Single-Site Ti-Oxide Moieties within a Silica Framework.

    Science.gov (United States)

    Verma, Priyanka; Kuwahara, Yasutaka; Mori, Kohsuke; Yamashita, Hiromi

    2017-03-13

    Ag nanoparticles (NPs) have gained great attention owing to their interesting plasmonic properties and efficient catalysis under visible-light irradiation. In this study, an Ag-based plasmonic catalyst supported on mesoporous silica with isolated and tetrahedrally coordinated single-site Ti-oxide moieties, namely, Ag/Ti-SBA-15, was designed with the purpose of utilizing the broad spectral range of solar energy. The Ti-SBA-15 support allows the deposition of small Ag NPs with a narrow size distribution. The chemical structure, morphology, and optical properties of the prepared catalyst were characterized by techniques such as UV/Vis, FT extended X-ray absorption fine structure, and X-ray photoelectron spectroscopy, field-emission SEM, TEM, and N 2 physisorption studies. The catalytic activity of Ag/Ti-SBA-15 in hydrogen production from ammonia borane by hydrolysis was significantly enhanced in comparison with Ag/SBA-15 without Ti-oxide moieties and Ag/TiO 2 /SBA-15 involving agglomerated TiO 2 , both in the dark and under light irradiation. Improved electron transfer under light irradiation caused by the creation of heterojunctions between Ag NPs and Ti-oxide moieties explains the results obtained in the present study. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Hysterectomy and Bilateral Salpingoovariectomy in a Transsexual Subject without Visible Scaring

    OpenAIRE

    Perrone, Anna Myriam; Scifo, Maria Cristina; Martelli, Valentina; Casadio, Paolo; Morselli, Paolo Giovanni; Pelusi, Giuseppe; Meriggiola, Maria Cristina

    2010-01-01

    Objective. To report on the use of laparoendoscopic single-site surgery (LESS) for the management of total hysterectomy (TH) with bilateral salpingoovariectomy (BSO) in a subject affected by gender identity disorder. Design. Case report. Setting. University Hospital. Patient(s). A 27-year-old affected by Gender Identity Disorder underwent a hysterectomy and BSO as part of surgical sex reassignment. Intervention(s). Laparoendoscopic single-site surgery access for TH and BSO. Main Outcome ...

  10. Recruitment Strategies and Costs Associated With Enrolling People With Insomnia and High Blood Pressure Into an Online Behavioral Sleep Intervention: A Single-Site Pilot Study.

    Science.gov (United States)

    Routledge, Faye S; Davis, Tara D; Dunbar, Sandra B

    Recruitment in clinical research is a common challenge and source of study failure. The reporting of recruitment methods and costs in hypertension trials is limited especially for smaller, single-site trials, online intervention trials, and trials using newer online recruitment strategies. The aims of this study are to describe and examine the feasibility of newer online-e-mail recruitment strategies and traditional recruitment strategies used to enroll participants with insomnia and high blood pressure into an online behavioral sleep intervention study (Sleeping for Heart Health). The 16 online-e-mail-based and traditional recruitment strategies used are described. Recruitment strategy feasibility was examined by study interest and enrollee yields, conversion rates, and costs (direct, remuneration, labor, and cost per enrollee). From August 2014 to October 2015, 183 people were screened and 58 (31.7%) enrolled in the study (51.1 ± 12.9 years, 63.8% female, 72.4% African American, 136 ± 12/88 ± 7 mm Hg, 87.9% self-reported hypertension, 67.2% self-reported antihypertensive medication use). The recruitment strategies yielding the highest enrollees were the university hospital phone waiting message system (25.4%), Craigslist (22.4%), and flyers (20.3%) at a per enrollee cost of $42.84, $98.90, and $128.27, respectively. The university hospital phone waiting message system (55.6%) and flyers (54.5%) had the highest interested participant to enrolled participant conversion rate of all recruitment strategies. Approximately 70% of all enrolled participants were recruited from the university hospital phone waiting message system, Craigslist, or flyers. Given the recruitment challenges that most researchers face, we encourage the documenting, assessing, and reporting of detailed recruitment strategies and associated recruitment costs so that other researchers may benefit.

  11. A Synthetic Single-Site Fe Nitrogenase: High Turnover, Freeze-Quench (57)Fe Mössbauer Data, and a Hydride Resting State.

    Science.gov (United States)

    Del Castillo, Trevor J; Thompson, Niklas B; Peters, Jonas C

    2016-04-27

    The mechanisms of the few known molecular nitrogen-fixing systems, including nitrogenase enzymes, are of much interest but are not fully understood. We recently reported that Fe-N2 complexes of tetradentate P3(E) ligands (E = B, C) generate catalytic yields of NH3 under an atmosphere of N2 with acid and reductant at low temperatures. Here we show that these Fe catalysts are unexpectedly robust and retain activity after multiple reloadings. Nearly an order of magnitude improvement in yield of NH3 for each Fe catalyst has been realized (up to 64 equiv of NH3 produced per Fe for P3(B) and up to 47 equiv for P3(C)) by increasing acid/reductant loading with highly purified acid. Cyclic voltammetry shows the apparent onset of catalysis at the P3(B)Fe-N2/P3(B)Fe-N2(-) couple and controlled-potential electrolysis of P3(B)Fe(+) at -45 °C demonstrates that electrolytic N2 reduction to NH3 is feasible. Kinetic studies reveal first-order rate dependence on Fe catalyst concentration (P3(B)), consistent with a single-site catalyst model. An isostructural system (P3(Si)) is shown to be appreciably more selective for hydrogen evolution. In situ freeze-quench Mössbauer spectroscopy during turnover reveals an iron-borohydrido-hydride complex as a likely resting state of the P3(B)Fe catalyst system. We postulate that hydrogen-evolving reaction activity may prevent iron hydride formation from poisoning the P3(B)Fe system. This idea may be important to consider in the design of synthetic nitrogenases and may also have broader significance given that intermediate metal hydrides and hydrogen evolution may play a key role in biological nitrogen fixation.

  12. Directory of Open Access Journals (Sweden)

    Marcos Tobias-Machado

    2012-12-01

    Full Text Available IntroductionPelvic organ prolapse is an ordinary disease with around 200.000 surgeries performed annually in the US to treat this condition. The surgical treatment for complete vaginal vault prolapse after hysterectomy involves abdominal or vaginal sacrocolpopexy. The purpose of this video is to demonstrate the steps of a laparoendoscopic single-site surgery (LESS sacrocolpopexy performed by a simplified knotless technique.Materials and MethodsA 52 year-old female submitted a total hysterectomy five years ago due to miomatosis who developed vault prolapse and urinary incontinence after surgery. She was treated by transumbilical LESS cutaneous retractor and a surgical glove attached to three trocars through a 3.5 cm umbilical incision. Patient was positioned in lithotomy, the Y-shape polypropylene mesh was passed through the trocar. Only conventional laparoscopic instruments were used for intrabdominal dissection of vagina and peritoneum. The mesh was fixed to the vaginal fornix using 3 continuous sutures held in extremities by polymeric clips. The last helical suture was fixed by polymeric clips to the sacral periosteum from the promontory to achieve good vaginal positioning without tension. The posterior peritoneum was closed over the mesh.ResultsThe operative time was 150 minutes, blood loss of approximately 100 mL and the patient was discharged after 18 hours with no immediate complications and a 3 months follow-up free of vault prolapse and urinary incontinence until now.ConclusionsLESS sacrocolpopexy performed with conventional instruments is feasible and a safe procedure reproducing surgical steps of conventional laparoscopic or robotic surgery.

  13. Combined robotic transanal total mesorectal excision (R-taTME) and single-site plus one-port (R-SSPO) technique for ultra-low rectal surgery-initial experience with a new operation approach.

    Science.gov (United States)

    Kuo, Li-Jen; Ngu, James Chi-Yong; Tong, Yiu-Shun; Chen, Chia-Che

    2017-02-01

    Robot-assisted rectal surgery is gaining popularity, and robotic single-site surgery is also being explored clinically. We report our initial experience with robotic transanal total mesorectal excision (R-taTME) and radical proctectomy using the robotic single-site plus one-port (R-SSPO) technique for low rectal surgery. Between July 2015 and March 2016, 15 consecutive patients with ultra-low rectal lesions underwent R-taTME followed by radical proctectomy using the R-SSPO technique by a single surgeon. The clinical and pathological results were retrospectively analyzed. The median operative time was 473 (range, 335-569) min, and the estimated blood loss was 33 (range, 30-50) mL. The median number of lymph nodes harvested was 12 (range, 8-18). The median distal resection margin was 1.4 (range, 0.4-3.5) cm, and all patients had clear circumferential resection margins. We encountered a left ureteric transection intraoperatively in one patient, and another patient required reoperation for postoperative adhesive intestinal obstruction. There was no 30-day mortality. R-taTME followed by radical proctectomy using the R-SSPO technique for patients with low rectal lesions is technically feasible and safe without compromising oncologic outcomes. However, there were considerable limitations and a steep learning curve using current robotic technology.

  14. Transumbilical laparoscopic treatment of Congenital Infantile Fibrosarcoma of the Ileum

    Directory of Open Access Journals (Sweden)

    G. Scirè

    2014-08-01

    Full Text Available Congenital-Infantile Fibrosarcoma (CIF is a malignant mesenchymal tumor representing 10-20% of soft-tissue tumors. Complete surgical resection is generally the treatment of choice. The most recurrent cytogenetic abnormality was identified as the traslocation t(12;15(p13:q25, which bears the fusion of Tel gene EVT6 with TrkC gene. This study describes a case of infantile fibrosarcoma of the ileum in a female newborn examined for intestinal occlusion and its laparoscopic treatment.

  15. Transumbilical breast augmentation (TUBA): patient selection, technique, and clinical experience.

    Science.gov (United States)

    Pound, E C; Pound, E C

    2001-07-01

    The TUBA procedure offers another approach to placing inflatable breast implants in the subglandular or submuscular position. It is an easy procedure to learn and to perform, using only a few relatively inexpensive specialized instruments. It also can be modified to use preexisting scars on the abdomen as the access point. The authors believe that complications seem to occur less with TUBA patients than with patients having breast augmentation by other approaches, an observation shared by other plastic surgeons offering the TUBA procedure. Limitations include the fact that only inflatable implants can be used. Also, with increasing distance from the breast, there is less control over manipulation of the pocket. Fortunately, the authors have not found this to be a problem in achieving symmetry. Furthermore, bleeding tends to be minimal with this approach. Nevertheless, should technical difficulties arise, conversion to a standard breast incision is an easy back-up option and should be discussed with the patient before surgery. Interest in the TUBA approach to breast augmentation continues to grow. Patients appreciate the lack of scarring on the breast and the short recovery that allows them to resume their normal lifestyle quickly. The authors' caseload has increased considerably over the past 8 years through word-of-mouth advertising from satisfied patients. Other plastic surgeons who offer this approach agree that patient demand for this operation continues to grow dramatically in their practices.

  16. The versatility of the transumbilical approach for laparotomy in infants

    African Journals Online (AJOL)

    neonates and infants with gastrointestinal surgical ... surgical procedures in neonates and infants. .... trauma to the rectus abdominis muscle, which can cause .... pancreatectomy for persistent hyperinsulinemic hypoglycemia of infancy.

  17. Evaluating the Effectiveness of an Antimicrobial Stewardship Program on Reducing the Incidence Rate of Healthcare-Associated Clostridium difficile Infection: A Non-Randomized, Stepped Wedge, Single-Site, Observational Study.

    Science.gov (United States)

    DiDiodato, Giulio; McArthur, Leslie

    2016-01-01

    The incidence rate of healthcare-associated Clostridium difficile infection (HA-CDI) is estimated at 1 in 100 patients. Antibiotic exposure is the most consistently reported risk factor for HA-CDI. Strategies to reduce the risk of HA-CDI have focused on reducing antibiotic utilization. Prospective audit and feedback is a commonly used antimicrobial stewardship intervention (ASi). The impact of this ASi on risk of HA-CDI is equivocal. This study examines the effectiveness of a prospective audit and feedback ASi on reducing the risk of HA-CDI. Single-site, 339 bed community-hospital in Barrie, Ontario, Canada. Primary outcome is HA-CDI incidence rate. Daily prospective and audit ASi is the exposure variable. ASi implemented across 6 wards in a non-randomized, stepped wedge design. Criteria for ASi; any intravenous antibiotic use for ≥ 48 hrs, any oral fluoroquinolone or oral second generation cephalosporin use for ≥ 48 hrs, or any antimicrobial use for ≥ 5 days. HA-CDI cases and model covariates were aggregated by ward, year and month starting September 2008 and ending February 2016. Multi-level mixed effect negative binomial regression analysis was used to model the primary outcome, with intercept and slope coefficients for ward-level random effects estimated. Other covariates tested for inclusion in the final model were derived from previously published risk factors. Deviance residuals were used to assess the model's goodness-of-fit. The dataset included 486 observation periods, of which 350 were control periods and 136 were intervention periods. After accounting for all other model covariates, the estimated overall ASi incidence rate ratio (IRR) was 0.48 (95% 0.30, 0.79). The ASi effect was independent of antimicrobial utilization. The ASi did not seem to reduce the risk of Clostridium difficile infection on the surgery wards (IRR 0.87, 95% CI 0.45, 1.69) compared to the medicine wards (IRR 0.42, 95% CI 0.28, 0.63). The ward-level burden of Clostridium

  18. Evaluating the Effectiveness of an Antimicrobial Stewardship Program on Reducing the Incidence Rate of Healthcare-Associated Clostridium difficile Infection: A Non-Randomized, Stepped Wedge, Single-Site, Observational Study.

    Directory of Open Access Journals (Sweden)

    Giulio DiDiodato

    Full Text Available The incidence rate of healthcare-associated Clostridium difficile infection (HA-CDI is estimated at 1 in 100 patients. Antibiotic exposure is the most consistently reported risk factor for HA-CDI. Strategies to reduce the risk of HA-CDI have focused on reducing antibiotic utilization. Prospective audit and feedback is a commonly used antimicrobial stewardship intervention (ASi. The impact of this ASi on risk of HA-CDI is equivocal. This study examines the effectiveness of a prospective audit and feedback ASi on reducing the risk of HA-CDI.Single-site, 339 bed community-hospital in Barrie, Ontario, Canada. Primary outcome is HA-CDI incidence rate. Daily prospective and audit ASi is the exposure variable. ASi implemented across 6 wards in a non-randomized, stepped wedge design. Criteria for ASi; any intravenous antibiotic use for ≥ 48 hrs, any oral fluoroquinolone or oral second generation cephalosporin use for ≥ 48 hrs, or any antimicrobial use for ≥ 5 days. HA-CDI cases and model covariates were aggregated by ward, year and month starting September 2008 and ending February 2016. Multi-level mixed effect negative binomial regression analysis was used to model the primary outcome, with intercept and slope coefficients for ward-level random effects estimated. Other covariates tested for inclusion in the final model were derived from previously published risk factors. Deviance residuals were used to assess the model's goodness-of-fit.The dataset included 486 observation periods, of which 350 were control periods and 136 were intervention periods. After accounting for all other model covariates, the estimated overall ASi incidence rate ratio (IRR was 0.48 (95% 0.30, 0.79. The ASi effect was independent of antimicrobial utilization. The ASi did not seem to reduce the risk of Clostridium difficile infection on the surgery wards (IRR 0.87, 95% CI 0.45, 1.69 compared to the medicine wards (IRR 0.42, 95% CI 0.28, 0.63. The ward-level burden of

  19. Surface science of single-site heterogeneous olefin polymerization catalysts

    OpenAIRE

    Kim, Seong H.; Somorjai, Gabor A.

    2006-01-01

    This article reviews the surface science of the heterogeneous olefin polymerization catalysts. The specific focus is on how to prepare and characterize stereochemically specific heterogeneous model catalysts for the Ziegler–Natta polymerization. Under clean, ultra-high vacuum conditions, low-energy electron irradiation during the chemical vapor deposition of model Ziegler–Natta catalysts can be used to create a “single-site” catalyst film with a surface structure that produces only isotactic ...

  20. Intramolecular electron transfer in single-site-mutated azurins

    DEFF Research Database (Denmark)

    Farver, O; Skov, L K; Pascher, T

    1993-01-01

    . Natl. Acad. Sci. U.S.A. 86, 6968-6972]. The RSSR- radical produced in the above reaction was reoxidized in a slower intramolecular electron-transfer process (30-70 s-1 at 298 K) concomitant with a further reduction of the Cu(II) ion. The temperature dependence of the latter rates was determined......, lambda = 135 kJ mol-1 for the reorganization energy was derived. When Trp48, situated midway between the donor and the acceptor, was replaced by Leu or Met, only a small change in the rate of intramolecular electron transfer was observed, indicating that the aromatic residue in this position...... is apparently only marginally involved in electron transfer in wild-type azurin. Pathway calculations also suggest that a longer, through-backbone path is more efficient than the shorter one involving Trp48. The former pathway yields an exponential decay factor, beta, of 6.6 nm-1. Another mutation, raising...

  1. New Developments in Robotics and Single-site Gynecologic Surgery.

    Science.gov (United States)

    Matthews, Catherine A

    2017-06-01

    Within the last 10 years there have been significant advances in minimal-access surgery. Although no emerging technology has demonstrated improved outcomes or fewer complications than standard laparoscopy, the introduction of the robotic surgical platform has significantly lowered abdominal hysterectomy rates. While operative time and cost were higher in robotic-assisted procedures when the technology was first introduced, newer studies demonstrate equivalent or improved robotic surgical efficiency with increased experience. Single-port hysterectomy has not improved postoperative pain or subjective cosmetic results. Emerging platforms with flexible, articulating instruments may increase the uptake of single-port procedures including natural orifice transluminal endoscopic cases.

  2. Early laparoendoscopic rendezvous for acute biliary pancreatitis: preliminary results.

    Science.gov (United States)

    Borzellino, G; Lombardo, F; Minicozzi, A M; Donataccio, M; Cordiano, C

    2010-02-01

    Early restored patency of the papilla has been hypothesized to reduce complications and mortality of acute biliary pancreatitis. The aim of this study was to evaluate the role of urgent laparoscopic cholecystectomy with intraoperative cholangiography and rendezvous when necessary in acute biliary pancreatitis natural history. Patients observed in the early stage of an acute biliary pancreatitis were included in the study. Operative risk assessment based on American Society of Anesthesiologists (ASA) score allowed the performance of urgent laparoscopic cholecystectomy within 72 h from onset of symptoms in 55 patients and a delayed intervention during the same admission in 21 patients. Intraoperative cholangiography was performed in all cases, and clearance of common bile duct was performed by flushing when possible, or rendezvous when necessary. Evolution of pancreatitis was evaluated with clinical and radiological monitoring. Urgent laparoscopic cholecystectomy was performed in all cases without conversion. At intraoperative cholangiography common bile duct was free in 25 patients, a papillary spasm was observed in 9, and common bile duct stones in 21 patients. Patency of the papilla was restored by flushing in 13 patients, while a rendezvous was necessary in 17 patients. The rate of organ failure and pancreatic necrosis was 1.8%, overall mortality was 1.8%, and overall morbidity 21.8%. No infectious complications of peripancreatic collections were observed. Urgent laparoscopic cholecystectomy with selective intraoperative rendezvous may be considered as a treatment option in the early stage of acute biliary pancreatitis.

  3. The Effect of Product Safety Courses on the Adoption and Outcomes of LESS Surgery

    OpenAIRE

    Toomey, Paul G.; Ross, Sharona B.; Choung, Edward; Donn, Natalie; Vice, Michelle; Luberice, Kenneth; Albrink, Michael; Rosemurgy, Alexander S.

    2015-01-01

    Background and Objectives: As technology in surgery evolves, the medical instrument industry is inevitability involved in promoting the use and appropriate (ie, effective and safe) application of its products. This study was undertaken to evaluate industry-supported product safety courses in laparoendoscopic single-site (LESS) surgery, by using the metrics of surgeons' adoption of the technique, safety of the procedure, and surgeons' perception of the surgery. Methods: LESS surgery courses th...

  4. Single-Port Transumbilical Laparoscopic Appendectomy: A Preliminary Multicentric Comparative Study in 87 Patients with Acute Appendicitis

    Directory of Open Access Journals (Sweden)

    Ramon Vilallonga

    2012-01-01

    Full Text Available Introduction. Laparoscopic appendectomy (LA has been performed in many approaches such as open, laparoscopic and recently Single Port Access (SPAA. In order to elucidate its potential advantages, we compared the two laparoscopic approaches. Methods. 87 patients were included in a multicentric study for suspected appendicitis in order to perform (SPAA appendectomy or laparoscopic appendectomy (LA. All outcomes, including blood loss, operative time, complications, and length of stay and pain were recorded prospectively. Results. There were 46 patients in the SPAA group and 41 in the LAG with a mean operative time of 40,4 minutes in the SPAA group and 35,0 minutes in the LA group. Only one patient was converted to an open approach. We described only 2 complications. Pain was graded 2,8 in the SPAA group and 2,9 in the LA group, according to the AVS after 24 hours. Patients in the SPAA Group were more satisfied (7,5 versus 6,9 (<0.05. Same results were found for the cosmetic result (8,6 versus 7,4 (<0.05. Conclusion. Using the single port approach feasible and safe. The true benefit of the technique should be assessed by new randomised controlled trials.

  5. Single site porphyrine-like structures advantages over metals for selective electrochemical CO2 reduction

    DEFF Research Database (Denmark)

    Bagger, Alexander; Ju, Wen; Varela, Ana Sofia

    2017-01-01

    Currently, no catalysts are completely selective for the electrochemical CO2 Reduction Reaction (CO2RR). Based on trends in density functional theory calculations of reaction intermediates we find that the single metal site in a porphyrine-like structure has a simple advantage of limiting...... the competing Hydrogen Evolution Reaction (HER). The single metal site in a porphyrine-like structure requires an ontop site binding of hydrogen, compared to the hollow site binding of hydrogen on a metal catalyst surface. The difference in binding site structure gives a fundamental energy-shift in the scaling...... relation of ∼0.3eV between the COOH* vs. H* intermediate (CO2RR vs. HER). As a result, porphyrine-like catalysts have the advantage over metal catalyst of suppressing HER and enhancing CO2RR selectivity....

  6. Robustness of high-fidelity Rydberg gates with single-site addressability

    Science.gov (United States)

    Goerz, Michael H.; Halperin, Eli J.; Aytac, Jon M.; Koch, Christiane P.; Whaley, K. Birgitta

    2014-09-01

    Controlled-phase (cphase) gates can be realized with trapped neutral atoms by making use of the Rydberg blockade. Achieving the ultrahigh fidelities required for quantum computation with such Rydberg gates, however, is compromised by experimental inaccuracies in pulse amplitudes and timings, as well as by stray fields that cause fluctuations of the Rydberg levels. We report here a comparative study of analytic and numerical pulse sequences for the Rydberg cphase gate that specifically examines the robustness of the gate fidelity with respect to such experimental perturbations. Analytical pulse sequences of both simultaneous and stimulated Raman adiabatic passage (STIRAP) are found to be at best moderately robust under these perturbations. In contrast, optimal control theory is seen to allow generation of numerical pulses that are inherently robust within a predefined tolerance window. The resulting numerical pulse shapes display simple modulation patterns and can be rationalized in terms of an interference between distinct two-photon Rydberg excitation pathways. Pulses of such low complexity should be experimentally feasible, allowing gate fidelities of order 99.90-99.99% to be achievable under realistic experimental conditions.

  7. Micro-analysis of plaque fluid from single-site fasted plaque

    International Nuclear Information System (INIS)

    Vogel, G.L.; Carey, C.M.; Chow, L.C.; Tatevossian, A.

    1990-01-01

    Despite the site-specific nature of caries, nearly all data on the concentration of ions relevant to the level of saturation of plaque fluid with respect to calcium phosphate minerals or enamel are from studies that used pooled samples. A procedure is described for the collection and analysis of inorganic ions relevant to these saturation levels in plaque fluid samples collected from a single surface on a single tooth. Various methods for examining data obtained by this procedure are described, and a mathematical procedure employing potential plots is recommended

  8. Editing and methylation at a single site by functionally interdependent activities

    Czech Academy of Sciences Publication Activity Database

    Rubio, M.A.T.; Gaston, K.W.; McKenney, K. M.; Fleming, I.M.C.; Paris, Zdeněk; Limbach, P.A.; Alfonzo, J. D.

    2017-01-01

    Roč. 542, č. 7642 (2017), s. 494-497 ISSN 0028-0836 R&D Projects: GA ČR GJ15-21450Y Institutional support: RVO:60077344 Keywords : encoded transfer-rnas * Leishmania tarentolae * Trypanosoma brucei * DNA deamination * anticodon loop * mitochondria * marsupials * discovery Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Biochemistry and molecular biology Impact factor: 40.137, year: 2016

  9. Clean Chlorination of Silica Surfaces by a Single-site Substitution Approach

    KAUST Repository

    Maity, Niladri

    2018-02-12

    A chlorination method for the selective substitution of well-defined isolated silanol groups of the silica surface has been developed using the catalytic Appel reaction. Spectroscopic analysis, complemented by elemental microanalysis studies, reveals that a quantitative chlorination could be achieved with highly dehydroxylated silica materials that exclusively possess non-hydrogen bonded silanol groups. The employed method did not leave any carbon or phosphorous residue on the silica surface and can be regarded as a promising tool for the future functionalization of metal oxide surfaces.

  10. Catalysis by Design: Well-Defined Single-Site Heterogeneous Catalysts

    KAUST Repository

    Pelletier, Jeremie; Basset, Jean-Marie

    2016-01-01

    concepts and tools of surface organometallic chemistry (SOMC). This approach operates by reacting organometallic compounds with surfaces of highly divided oxides (or of metal nanoparticles). This strategy has a solid track record to reveal structure

  11. Selective alkane activation with single-site atoms on amorphous support

    Science.gov (United States)

    Hock, Adam S.; Schweitzer, Neil M.; Miller, Jeffrey T.; Hu, Bo

    2015-11-24

    The present invention relates generally to catalysts and methods for use in olefin production. More particularly, the present invention relates to novel amorphously supported single-center, Lewis acid metal ions and use of the same as catalysts.

  12. Rayleigh scattering from single-site polysylane adsorbed on silicon: Theory

    NARCIS (Netherlands)

    Wijers, Christianus M.J.

    1986-01-01

    An ordered set of dipoles with mutual interaction in the close vicinity of a dielectric surface is studied. The solution of that particular theoretical problem is given rigorously both for the static and dynamic case. It can serve as a description of the polysylane molecules formed at the surface of

  13. Clean Chlorination of Silica Surfaces by a Single-site Substitution Approach

    KAUST Repository

    Maity, Niladri; Barman, Samir; Abou-Hamad, Edy; D'Elia, Valerio; Basset, Jean-Marie

    2018-01-01

    A chlorination method for the selective substitution of well-defined isolated silanol groups of the silica surface has been developed using the catalytic Appel reaction. Spectroscopic analysis, complemented by elemental microanalysis studies, reveals that a quantitative chlorination could be achieved with highly dehydroxylated silica materials that exclusively possess non-hydrogen bonded silanol groups. The employed method did not leave any carbon or phosphorous residue on the silica surface and can be regarded as a promising tool for the future functionalization of metal oxide surfaces.

  14. High-quality Thermodynamic Data on the Stability Changes of Proteins Upon Single-site Mutations

    Energy Technology Data Exchange (ETDEWEB)

    Pucci, Fabrizio, E-mail: fapucci@ulb.ac.be; Bourgeas, Raphaël, E-mail: rbourgeas@ulb.ac.be; Rooman, Marianne, E-mail: mrooman@ulb.ac.be [Department of BioModeling, BioInformatics and BioProcesses, Université Libre de Bruxelles, CP 165/61, Roosevelt Avenue 50, 1050 Brussels, Belgium and Interuniversity Institute of Bioinformatics in Brussels, CP 263, Triumph Bld, 1050 Brussels (Belgium)

    2016-06-15

    We have set up and manually curated a dataset containing experimental information on the impact of amino acid substitutions in a protein on its thermal stability. It consists of a repository of experimentally measured melting temperatures (T{sub m}) and their changes upon point mutations (ΔT{sub m}) for proteins having a well-resolved x-ray structure. This high-quality dataset is designed for being used for the training or benchmarking of in silico thermal stability prediction methods. It also reports other experimentally measured thermodynamic quantities when available, i.e., the folding enthalpy (ΔH) and heat capacity (ΔC{sub P}) of the wild type proteins and their changes upon mutations (ΔΔH and ΔΔC{sub P}), as well as the change in folding free energy (ΔΔG) at a reference temperature. These data are analyzed in view of improving our insights into the correlation between thermal and thermodynamic stabilities, the asymmetry between the number of stabilizing and destabilizing mutations, and the difference in stabilization potential of thermostable versus mesostable proteins.

  15. Neoadjuvant chemotherapy for primary adenocarcinomas of the urinary bladder: a single-site experience.

    Science.gov (United States)

    Yu, Bin; Zhou, Jin; Cai, Hongzhou; Xu, Ting; Xu, Zicheng; Zou, Qing; Gu, Min

    2015-01-28

    Adenocarcinoma of the urinary bladder is a rare malignancy. Radical surgery is suggested as the best available treatment for early-stage disease, but there is currently no consensus on standard chemotherapy regimen for advanced stage. We assessed the feasibility and effect of neoadjuvant chemotherapy with gemcitabine and cisplatin (GC) plus S-1 for patients with locally advanced primary adenocarcinomas of the urinary bladder. Six patients with locally advanced urachal or non-urachal (n = 3, each) primary adenocarcinoma of the bladder were treated from October 2010 to October 2013 at a single center. All the patients were treated with 3 cycles (21d, each) of GC plus S-1 (gemcitabine, 1000 mg/m2, days 1 and 8; cisplatin, 70 mg/m2, day 2; and S-1, 50 mg bid, day 1-14). After neoadjuvant chemotherapy, patients with urachal cancer were treated with en bloc radical cystectomy and umbilectomy; the remaining 3 patients were treated with cystectomy. All patients successfully completed the neoadjuvant chemotherapy without serious side effects. Two patients were assessed as complete response, 2 as partial response, 1 as stable disease and 1 as progressive disease. Despite the limitations of a small study population, the GC plus S-1 regimen for locally advanced primary adenocarcinoma of the urinary bladder was effective, and facilitated the success of surgery to a certain extent. Short follow-up time was also a limitation of our study. More studies are needed to evaluate the results.

  16. Single-site Lennard-Jones models via polynomial chaos surrogates of Monte Carlo molecular simulation

    KAUST Repository

    Kadoura, Ahmad Salim; Siripatana, Adil; Sun, Shuyu; Knio, Omar; Hoteit, Ibrahim

    2016-01-01

    In this work, two Polynomial Chaos (PC) surrogates were generated to reproduce Monte Carlo (MC) molecular simulation results of the canonical (single-phase) and the NVT-Gibbs (two-phase) ensembles for a system of normalized structureless Lennard

  17. Single-site approximation for the s-f model of antiferromagnetic semiconductors

    International Nuclear Information System (INIS)

    Takahashi, Masao; Nolting, Wolfgang

    2001-01-01

    For the s-f model of an antiferromagnetic semiconductor, the effect of the antiferromagnetic ordering of the localized spins on the conduction-electron state is investigated over a wide range of exchange strengths by combining the effective-medium approach with the Green's function in the 2x2 sublattice Bloch function representation. The band splitting due to the reduced magnetic Brillouin zone occurs below the Neel temperature. There is a marked effect of the thermal fluctuation of the antiferromagnetically ordered localized spins on the conduction electron at the energies near the top (bottom) of the lower- (higher-) energy subband

  18. Ground surface temperature history at a single site in southern Portugal reconstructed from borehole temperatures

    Czech Academy of Sciences Publication Activity Database

    Correia, A.; Šafanda, Jan

    2001-01-01

    Roč. 29, 3/4 (2001), s. 155-165 ISSN 0921-8181 Grant - others:NATO(XX) CP(CZ)4/D/96/PO; UNESCO(XX) IGCP No.428 Institutional research plan: CEZ:AV0Z3012916 Keywords : recent climate * global warming * borehole temperatures * Portugal Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.381, year: 2001

  19. [Choledocholithiasis and pregnancy. Hybrid laparo-endoscopic treatment in one step].

    Science.gov (United States)

    Valadez-Caballero, David; González-Santamaría, Roberto; Soto-Mendoza, Héctor; Alberto Blanco-Figueroa, Jorge; Flores-Pantoja, Juan Manuel

    2014-01-01

    Complications associated with choledocholithiasis are uncommon during pregnancy. However, when it occurs, the morbidity and mortality related for the product and the mother increases, so a proper treatment is imperative in these patients. A 25-year-old pregnant woman on her second trimester. The current condition was started four days prior to the hospital admission with abdominal pain in the right upper quadrant with nausea and vomit.Twenty-four hours later jaundice and dark urine is observed. Physical examination shows scleral jaundice, right upper quadrant abdominal pain without peritoneal irritation. Uterus at umbilicus level without uterine activity. Uterus at umbilicus level without uterine activity. Laboratory tests showed elevated bilirubin and transaminases without leukocytosis; ultrasound reported live intrauterine unique product, with a heart rate of 128 beats per minute, gallbladder with multiple images inside that cast acoustic shadowing, and a 10 mm common bile duct dilated bile duct with dilatation of intrahepatic bile ducts. It was perform laparoscopic cholecystectomy with intraoperative cholangiography and placement of a transcystic jaguar guide for selective cannulation of the common bile duct. Intraoperative endoscopic retrograde cholangiopancreatography was performed with endoscopic stone extraction. The outcome was satisfactory with a hospital discharge at 48 hours. Current evidence has shown that the combined use of laparoscopy and therapeutic endoscopic cholangiography in one step is effective for the treatment of choledocholithiasis, decreasing the risk of complications associated with cannulation of the bile duct.

  20. Single port laparoscopic surgery

    DEFF Research Database (Denmark)

    Springborg, Henrik; Istre, Olav

    2012-01-01

    LESS, or laparo-endoscopic single site surgery, is a promising new method in minimally invasive surgery. An increasing number of surgical procedures are being performed using this technique, however, its large-scale adoption awaits results of prospective randomized controlled studies confirming...... potential benefits. Theoretically, cosmetic outcomes, postoperative pain and complication rates could be improved with use of single site surgery. This study describes introduction of the method in a private hospital in Denmark, in which 40 patients have been treated for benign gynecologic conditions....... Although the operations described are the first of their kind reported in Denmark, favorable operating times and very low complication rates are seen. It is the authors' opinion that in addition to being feasible for hysterectomy, single port laparoscopy may become the preferred method for many simple...

  1. MD simulations and QM/MM calculations show that single-site mutations of cytochrome P450BM3 alter the active site’s complexity and the chemoselectivity of oxidation without changing the active species† †Electronic supplementary information (ESI) available: The RMS deviation of the protein during 100 ns (and 200 ns) of simulation and the total QM/MM and ZPE energies, as well as the Cartesian coordinates of all of the computed species. See DOI: 10.1039/c7sc01932g

    Science.gov (United States)

    Dubey, Kshatresh Dutta; Wang, Binju; Vajpai, Manu

    2017-01-01

    It is a long-standing mechanistic consensus that the mutation of the proton-shuttle mediator Threonine (T) in Cytochrome P450 enzymes severs the water channel and thereby quenches the formation of the active species: the high-valent iron(iv)-oxo porphyrin π-cation radical species, compound I (Cpd I). Using MD simulations and hybrid QM/MM calculations of P450BM3 we demonstrate that this is not the case. Thus, while the original water channel is disrupted in the T268A mutant of the enzyme, a new channel is formed that generates Cpd I. With this new understanding, we address the puzzling regiochemical and kinetic-isotope effect (KIE) results (Volz et al., J. Am. Chem. Soc., 2002, 124, 9724–9725) on the sulfoxidation and N-dealkylation of dimethyl-(4-methylsulfanyl-phenyl)-amine by wild type (WT) P450BM3 and its T268A vs. F87A mutants. We show that the observed variable ratio of S/Me oxidation for these enzymes, vis-à-vis the constant KIE, originates from Cpd I being the sole oxidant. Thus, while the conserved KIE probes the conserved nature of the transition state, the variable regiochemical S/Me ratio reflects the active-site reorganization in the mutants: the shifted location of the new water channel in T268A tightens the binding of the S-end by Cpd I and increases the S/Me ratio, whereas the absence of π-interaction with the S-end in F87A creates a looser binding that lowers the S/Me ratio. Our results match the experimental findings. As such, this study sheds light on puzzling experimental results, and may shift a central paradigm in P450 research. The broader implication on enzymatic research is that a single-site mutation is not a localised alteration but one that may lead to a profound change in the active site, sufficiently so as to change the chemoselectivity of catalyzed reactions. PMID:29568477

  2. Robotic single port cholecystectomy (R-LESS-C): experience in 36 patients.

    Science.gov (United States)

    Uras, Cihan; Böler, Deniz Eren; Ergüner, Ilknur; Hamzaoğlu, Ismail

    2014-07-01

    Laparoendoscopic single-site surgery (LESS) has emerged as a result of a search for "pain-less" and "scar-less" surgery. Laparoendoscopic single-site cholecystectomy (LESS-C) is probably the most common application in general surgery, although it harbors certain limitations. It was proposed that the da Vinci Single-Site (Si) robotic system may overcome some of the difficulties experienced during LESS, providing three dimensional views and the ability to work in a right-handed fashion. Thirty-six robotic single port cholecystectomies (R-LESS-C) performed with the da Vinci Si robotic system are evaluated in this paper R-LESS-C performed in 36 patients were reviewed. The data related to the perioperative period (i.e., anesthesia time, operation time, docking time, and console time) was recorded prospectively, whereas the hospitalization period, postoperative visual analogue scale (VAS) pain scores were collected retrospectively. A total number of 36 patients, with a mean age of 40.1 years (21-64 years), underwent R-LESS-C. There were five men and 31 women. The mean anesthesia and operation times were 79.3 minutes (45-130 minutes) and 61.8 minutes (34-110 minutes), respectively. The mean docking time was 9.8 minutes (4-30 minutes) and the mean console time was 24.9 minutes (7-60 minutes). The mean hospital stay was 1.05 days (1-2 days) and the mean pain score (VAS) was 3.6 (2-8) in the first 24 hours. Incisional hernia was recorded in one patient. R-LESS-C can be performed reliably with acceptable operative times and safety. The da Vinci Si robotic system may ease LESS-C. Two issues should be considered for routine use: expensive resources are needed and the incidence of incisional hernia may increase. Copyright © 2013. Published by Elsevier B.V.

  3. Silica-supported, single-site titanium catalysts for olefin epoxidation. A molecular precursor strategy for control of catalyst structure.

    Science.gov (United States)

    Jarupatrakorn, Jonggol; Don Tilley, T

    2002-07-17

    A molecular precursor approach involving simple grafting procedures was used to produce site-isolated titanium-supported epoxidation catalysts of high activity and selectivity. The tris(tert-butoxy)siloxy titanium complexes Ti[OSi(O(t)Bu)(3)](4) (TiSi4), ((i)PrO)Ti[OSi(O(t)Bu)(3)](3) (TiSi3), and ((t)BuO)(3)TiOSi(O(t)Bu)(3) (TiSi) react with the hydroxyl groups of amorphous Aerosil, mesoporous MCM-41, and SBA-15 via loss of HO(t)Bu and/or HOSi(O(t)Bu)(3) and introduction of titanium species onto the silica surface. Powder X-ray diffraction, nitrogen adsorption/desorption, infrared, and diffuse reflectance ultraviolet spectroscopies were used to investigate the structures and chemical natures of the surface-bound titanium species. The titanium species exist mainly in isolated, tetrahedral coordination environments. Increasing the number of siloxide ligands in the molecular precursor decreases the amount of titanium that can be introduced this way, but also enhances the catalytic activity and selectivity for the epoxidation of cyclohexene with cumene hydroperoxide as oxidant. In addition, the high surface area mesoporous silicas (MCM-41 and SBA-15) are more effective than amorphous silica as supports for these catalysts. Supporting TiSi3 on the SBA-15 affords highly active cyclohexene epoxidation catalysts (0.25-1.77 wt % Ti loading) that provide turnover frequencies (TOFs) of 500-1500 h(-1) after 1 h (TOFs are reduced by about half after calcination). These results demonstrate that oxygen-rich siloxide complexes of titanium are useful as precursors to supported epoxidation catalysts.

  4. Skeletal survey quality in non-accidental injury – A single site evaluation of the effects of imaging checklists

    International Nuclear Information System (INIS)

    Weldon, J.; Price, R.

    2016-01-01

    Aims: Evidence suggests ongoing practice variability in the quality of skeletal survey examinations for non-accidental injury. The purpose of the study was to investigate the effects on examination quality following the implementation of imaging checklists. Method: A retrospective evaluation of skeletal survey examinations was carried out on studies performed between January 2007 and November 2014 at a large District General Hospital Trust. Longitudinal assessment was undertaken over three periods, before and following the introduction of two versions of imaging checklists, following modifications. Examinations were assessed and scored using three measures for completeness and quality employing a modified established scoring system against a professional body national standards document. Results: A total of 121 examinations met the inclusion criteria, all quality assessment measures showed improvements between each period. Examination completeness increased from median of 13 projections, to 20 throughout the three periods. Mann Whitney u Tests showed significant differences between each period. The mean combined anatomy score reduced from 3.11 to 1.10 throughout the three periods. Independent t Tests and Mann Whitney u Tests showed a significant decrease throughout the study period. Total percentage examination quality increased from median 44–83% throughout the three periods. Independent t Tests also showed significant differences between each period. Conclusion: The use of imaging checklists to improve quality and to support the optimal acquisition of the non-accidental injury skeletal survey shows encouraging results. However, further work is needed to optimise content and the use of checklists in practice. - Highlights: • Skeletal survey examinations for non-accidental practices have been shown to vary in content and in quality. • Checklists have demonstrated improvements in compliance to guidelines across health disciplines and in various settings. • Practice was assessed following the introduction of checklists using a modified scoring system against national standards. • Improvement in the content and quality were observed in all three measures. • Imaging checklists demonstrated improvements to skeletal survey examination content and quality.

  5. Intraoperative Radiation Using Low-Kilovoltage X-Rays for Early Breast Cancer: A Single Site Trial.

    Science.gov (United States)

    Silverstein, Melvin J; Epstein, Melinda S; Lin, Kevin; Chen, Peter; Khan, Sadia; Snyder, Lincoln; Guerra, Lisa E; De Leon, Cristina; Mackintosh, Ralph; Coleman, Colleen; Lopez, January; Kim, Brian

    2017-10-01

    Two prospective, randomized trials, TARGIT-A and ELIOT, have shown intraoperative radiation therapy (IORT) to be a safe alternative to whole breast radiation therapy following breast-conserving surgery for selected low-risk patients. However, minimal data are available about the clinical effectiveness of this modality of treatment using the Xoft ® Axxent ® Electronic Brachytherapy (eBx ® ) System ® . A total of 201 patients with 204 early-stage breast cancers were enrolled in a prospective X-ray IORT trial from June 2010 to September 2013. All tumors were treated with breast-conserving surgery and IORT. Data were collected at 1 week, 1 month, 6 months, 1 year, and yearly thereafter. With a median follow-up of 50 months, there have been seven ipsilateral breast tumor events (IBTE), no regional or distant recurrences, and no breast cancer-related deaths. One IBTE was within the IORT field, four outside of the IORT field but within the same quadrant as the index cancer, and two were new biologically different cancers in different quadrants. Three events were in patients who deviated from the protocol criteria. Kaplan-Meier analysis projects that 2.9% of patients will recur locally at 4 years. Recurrence rates observed in this trial were comparable to those of the TARGIT-A and ELIOT trials as well as the retrospective TARGIT-R trial. The low complication rates previously reported by our group as well as the low recurrence rates reported in this study support the cautious use and continued study of IORT in selected women with low-risk breast cancer.

  6. Tuning of the Lethal Response to Multiple Stressors with a Single-Site Mutation during Clinical Infection by Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Krishan Kumar

    2017-10-01

    Full Text Available The agr system of Staphylococcus aureus promotes invasion of host tissues, and as expected, agents that block agr quorum sensing have anti-infective properties. Paradoxically, agr-defective mutants are frequently recovered from patients, especially those persistently infected with S. aureus. We found that an agr deficiency increased survival of cultured bacteria during severe stress, such as treatment with gentamicin, ciprofloxacin, heat, or low pH. With daptomycin, deletion of agr decreased survival. Therefore, agr activity can be either detrimental or protective, depending on the type of lethal stress. Deletion of agr had no effect on the ability of the antimicrobials to block bacterial growth, indicating that agr effects are limited to lethal action. Thus, the effect of an agr deletion is on bacterial tolerance, not resistance. For gentamicin and daptomycin, activity can be altered by agr-regulated secreted factors. For ciprofloxacin, a detrimental function was downregulation of glutathione peroxidase (bsaA, an enzyme responsible for defense against oxidative stress. Deficiencies in agr and bsaA were epistatic for survival, consistent with agr having a destructive role mediated by reactive oxygen species. Enhanced susceptibility to lethal stress by wild-type agr, particularly antimicrobial stress, helps explain why inactivating mutations in S. aureus agr commonly occur in hospitalized patients during infection. Moreover, the agr quorum-sensing system of S. aureus provides a clinically relevant example in which a single-step change in the response to severe stress alters the evolutionary path of a pathogen during infection.

  7. Quasichemical theory and the description of associating fluids relative to a reference: Multiple bonding of a single site solute

    Science.gov (United States)

    Bansal, Artee; Chapman, Walter G.; Asthagiri, D.

    2017-09-01

    We derive an expression for the chemical potential of an associating solute in a solvent relative to the value in a reference fluid using the quasichemical organization of the potential distribution theorem. The fraction of times the solute is not associated with the solvent, the monomer fraction, is expressed in terms of (a) the statistics of occupancy of the solvent around the solute in the reference fluid and (b) the Widom factors that arise because of turning on solute-solvent association. Assuming pair-additivity, we expand the Widom factor into a product of Mayer f-functions and the resulting expression is rearranged to reveal a form of the monomer fraction that is analogous to that used within the statistical associating fluid theory (SAFT). The present formulation avoids all graph-theoretic arguments and provides a fresh, more intuitive, perspective on Wertheim's theory and SAFT. Importantly, multi-body effects are transparently incorporated into the very foundations of the theory. We illustrate the generality of the present approach by considering examples of multiple solvent association to a colloid solute with bonding domains that range from a small patch on the sphere to a Janus particle to a solute whose entire surface is available for association.

  8. Controlled synthesis of biodegradable lactide polymers and copolymers using novel in situ generated or single-site stereoselective polymerisation initiators

    NARCIS (Netherlands)

    Zhong, Zhiyuan; Dijkstra, Pieter J.; Feijen, Jan

    2004-01-01

    Polylactides and their copolymers are key biodegradable polymers used widely in biomedical, pharmaceutical and ecological applications. The development of synthetic pathways and catalyst/initiator systems to produce pre-designed polylactides, as well as the fundamental understanding of the

  9. Contributing factors of elective surgical case cancellation: a retrospective cross-sectional study at a single-site hospital.

    Science.gov (United States)

    Yu, Kaiye; Xie, Xiaolei; Luo, Li; Gong, Renrong

    2017-09-11

    Case cancellation (CC) has significant impact on the efficiency of operating room (OR) management, which can be mitigated by taking preventive measures. In this study, using the data of the West China Hospital (WCH), we identified the effect of contributing factors and recommended hospital interventions to facilitate CC prevention. We conducted a retrospective review of 11,331 elective surgical cases from January 1 to December 31, 2014. CC reasons were grouped into six categories. The methods of descriptive statistics and hypothesis test were used to identify the effect of factors. CC reasons (746) were divided into six broad categories: workup related (preoperative diagnostic assessment issues or sudden medical condition changes) (25.8%), non-specified reasons (25.8%), coordination issues (15.1%), patient related (13.0%), support system issues (11.8%), and doctor related (8.5%). The types of the most frequently performed operations are identified, as well as their CRs. The cancellation rate (CR) of males was lower than that of females (16.7% to 18.3%). A large difference in the CRs existed among doctors. The CR on Monday was significantly higher than the other four weekdays. Workup related issues, the types of procedures, the menstrual cycle of females, highly imbalanced CRs among doctors, and tendency of cancellation on Monday are the major identified factors, which account for a significant amount of preventable cancellations. It is suggested that corresponding hospital interventions can reduce CR and improve OR efficiency, including maintaining effective coordination, good communication and well-designed preoperative assessment processes, focusing on the type of procedures which are more time-consuming and complex, paying special attention to the physiology of females during surgery planning, taking measures to reduce CR of top eight doctors, and improving surgery scheduling on Monday.

  10. Fixation method does not affect restoration of rotation center in hip replacements: A single-site retrospective study

    Directory of Open Access Journals (Sweden)

    Wegner Alexander

    2012-06-01

    Full Text Available Abstract Background Aseptic loosening is one of the greatest problems in hip replacement surgery. The rotation center of the hip is believed to influence the longevity of fixation. The aim of this study was to compare the influence of cemented and cementless cup fixation techniques on the position of the center of rotation because cemented cup fixation requires the removal of more bone for solid fixation than the cementless technique. Methods We retrospectively compared pre- and post-operative positions of the hip rotation center in 25 and 68 patients who underwent artificial hip replacements in our department in 2007 using cemented or cementless cup fixation, respectively, with digital radiographic image analysis. Results The mean horizontal and vertical distances between the rotation center and the acetabular teardrop were compared in radiographic images taken pre- and post-operatively. The mean horizontal difference was −2.63 mm (range: -11.00 mm to 10.46 mm, standard deviation 4.23 mm for patients who underwent cementless fixation, and −2.84 mm (range: -10.87 to 5.30 mm, standard deviation 4.59 mm for patients who underwent cemented fixation. The mean vertical difference was 0.60 mm (range: -20.15 mm to 10.00 mm, standard deviation 3.93 mm and 0.41 mm (range: -9.26 mm to 6.54 mm, standard deviation 3.58 mm for the cementless and cemented fixation groups, respectively. The two fixation techniques had no significant difference on the position of the hip rotation center in the 93 patients in this study. Conclusions The hip rotation center was similarly restored using either the cemented or cementless fixation techniques in this patient cohort, indicating that the fixation technique itself does not interfere with the position of the center of rotation. To completely answer this question further studies with more patients are needed.

  11. Fixation method does not affect restoration of rotation center in hip replacements: A single-site retrospective study

    OpenAIRE

    Wegner, Alexander; Kauther, Max Daniel; Landgraeber, Stefan; von Knoch, Marius

    2012-01-01

    Abstract Background Aseptic loosening is one of the greatest problems in hip replacement surgery. The rotation center of the hip is believed to influence the longevity of fixation. The aim of this study was to compare the influence of cemented and cementless cup fixation techniques on the position of the center of rotation because cemented cup fixation requires the removal of more bone for solid fixation than the cementless technique. Methods We retrospectively compared pre- and post-operativ...

  12. Mechanistic studies aimed at the development of single site metal alkoxide catalysts for the production of polyoxygenates from renewable resources.

    Energy Technology Data Exchange (ETDEWEB)

    Chisholm, Malcolm H. [The Ohio State Univ., Columbus, OH (United States)

    2015-12-15

    The work proposed herein follows on directly from the existing 3 year grant and the request for funding is for 12 months to allow completion of this work and graduation of current students supported by DOE. The three primary projects are as follows. 1.) A comparative study of the reactivity of LMg(OR) (solvent), where L= a β-diiminate or pyrromethene ligand, in the ring-opening of cyclic esters. 2.) The homopolymerization of expoxides, particularly propylene oxide and styrene oxide, and their copolymerizations with carbon dioxide or organic anhydrides to yield polycarbonates or polyesters, respectively. 3.) The development of well-defined bismuth (III) complexes for ring-opening polymerizations that are tolerant of both air and water. In each of these topics special emphasis is placed on developing a detailed mechanistic understanding of the ring-opening event and how this is modified by the employment of specific metal and ligand combinations. This document also provides a report on findings of the past grant period that are not yet in the public domain/published and shows how the proposed work will bring the original project to conclusion.

  13. Supported Single-Site Ti(IV) on a Metal–Organic Framework for the Hydroboration of Carbonyl Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhiyuan [College; amp, Molecular Sciences, Institute of Advanced Studies, Wuhan University, Wuhan 430072, PR China; Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Liu, Dong [College; amp, Molecular Sciences, Institute of Advanced Studies, Wuhan University, Wuhan 430072, PR China; Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Camacho-Bunquin, Jeffrey [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Zhang, Guanghui [Department; Yang, Dali [College; amp, Molecular Sciences, Institute of Advanced Studies, Wuhan University, Wuhan 430072, PR China; Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; López-Encarnación, Juan M. [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Department; Xu, Yunjie [Department; Ferrandon, Magali S. [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Niklas, Jens [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Poluektov, Oleg G. [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Jellinek, Julius [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Lei, Aiwen [College; amp, Molecular Sciences, Institute of Advanced Studies, Wuhan University, Wuhan 430072, PR China; Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Bunel, Emilio E. [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Delferro, Massimiliano [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States

    2017-10-10

    ABSTRACT: A stable and structurally well-defined titanium alkoxide catalyst supported on a metal-organic-framework (MOF) of UiO-67 topology (ANL1-Ti(OiPr)2) was synthesized and fully characterized by a variety of analytical and spectroscopic techniques, including BET, TGA, PXRD, XAS, DRIFT, SEM, and DFT computations. The Ti-functionalized MOF was demonstrated active for the catalytic hydroboration of a wide range of aldehydes and ketones with HBpin as the boron source. Compared to traditional homogeneous and supported hydroboration catalysts, ANL1-Ti(OiPr)2 is completely recyclable and reusable, making it a promising hydroboration catalyst alternative for green and sustainable chemical synthesis. DFT calculations suggest that the catalytic hydroboration proceeds via a (1) hydride transfer between the active Ti-hydride species and a carbonyl moiety (rate determining step), and (2) alkoxide transfer (intramolecular σ-bond metathesis) to generate the boronate ester product.

  14. Large Conization and Laparoendoscopic Single-Port Pelvic Lymphadenectomy in Early-Stage Cervical Cancer for Fertility Preservation

    Directory of Open Access Journals (Sweden)

    Polat Dursun

    2013-01-01

    Full Text Available Fertility preservation in early-stage cervical cancer is a hot topic in gynecologic oncology. Although radical vaginal trachelectomy (RVT is suggested as a fertility preserving approach, there are some serious concerns like cervical stenosis, second trimester loss, preterm delivery in survivors, and lack of residual tumor in the majority of the surgical specimens. Therefore, less radical surgical operations have been proposed in early-stage cervical carcinomas. On the other hand, single-incision laparoscopic surgery (SILS is an evolving endoscopic approach for minimal access surgery. In this report, we present a case with early-stage cervical cancer who wishes to preserve fertility. We successfully performed single-port pelvic lymphadenectomy and large conization to preserve fertility potential of the patient. We think that combination of less radical approach like conization and single-port pelvic lymphadenectomy might be less minimally invasive and is still an effective surgical approach in well-selected cases with cervical carcinomas. Incorporation of single-port laparoscopy into the minimally invasive fertility sparing management of the cervical cancer will improve patients outcome with less complications and better cosmesis. Further studies are needed to reach a clear conclusion.

  15. Sources of pain in laparoendoscopic gynecological surgeons: An analysis of ergonomic factors and proposal of an aid to improve comfort.

    Science.gov (United States)

    Lee, Sa Ra; Shim, Sunah; Yu, Taeri; Jeong, Kyungah; Chung, Hye Won

    2017-01-01

    Minimally invasive surgery (MIS) offers cosmetic benefits to patients; however, surgeons often experience pain during MIS. We administered an ergonomic questionnaire to 176 Korean laparoscopic gynecological surgeons to determine potential sources of pain during surgery. Logistic regression analysis was used to identify factors that had a significant impact on gynecological surgeons' pain. Operating table height at the beginning of surgery and during the operation were significantly associated with neck and shoulder discomfort (P ergonomic solutions to reduce gynecological laparoscopic surgeons' pain. Based on our results, we propose the use of an ergonomic surgical step stool to reduce physical pain related to performing laparoscopic operations.

  16. Sources of pain in laparoendoscopic gynecological surgeons: An analysis of ergonomic factors and proposal of an aid to improve comfort.

    Directory of Open Access Journals (Sweden)

    Sa Ra Lee

    Full Text Available Minimally invasive surgery (MIS offers cosmetic benefits to patients; however, surgeons often experience pain during MIS. We administered an ergonomic questionnaire to 176 Korean laparoscopic gynecological surgeons to determine potential sources of pain during surgery. Logistic regression analysis was used to identify factors that had a significant impact on gynecological surgeons' pain. Operating table height at the beginning of surgery and during the operation were significantly associated with neck and shoulder discomfort (P <0.001. The ability to control the operating table height was the single factor most significantly associated with neck (P <0.001 and shoulder discomfort (P <0.001. Discomfort of the hand/digits was significantly associated with the trocar site (P = 0.035. The type of electrocautery activation switch and foot pedal were significantly related to surgeons' foot and leg discomfort (P <0.001. In evaluating the co-occurrence of pain in 4 different sites (neck, shoulder, back, hand/digits, the neck and shoulder were determined to have the highest co-occurrence of pain (Spearman's ρ = 0.64, P <0.001. These results provide guidance for identifying ergonomic solutions to reduce gynecological laparoscopic surgeons' pain. Based on our results, we propose the use of an ergonomic surgical step stool to reduce physical pain related to performing laparoscopic operations.

  17. Recent technological advancements in laparoscopic surgical instruments

    Science.gov (United States)

    Subido, Edwin D. C.; Pacis, Danica Mitch M.; Bugtai, Nilo T.

    2018-02-01

    Laparoscopy was a progressive step to advancing surgical procedures as it minimised the scars left on the body after surgery, compared to traditional open surgery. Many years later, single-incision laparoscopic surgery (SILS) was created where, instead of having multiple incisions, only one incision is made or multiple small incisions in one location. SILS, or laparoendoscopic single-site surgery (LESS), may produce lesser scars but drawbacks for the surgeons are still present. This paper aims to present related literature of the recent technological developments in laparoscopic tools and procedure particularly in the vision system, handheld instruments. Tech advances in LESS will also be shown. Furthermore, this review intends to give an update on what has been going on in the surgical robot market and state which companies are interested and are developing robotic systems for commercial use to challenge Intuitive Surgical's da Vinci Surgical System that currently dominates the market.

  18. Option Grids to facilitate shared decision making for patients with Osteoarthritis of the knee: protocol for a single site, efficacy trial.

    Science.gov (United States)

    Marrin, Katy; Wood, Fiona; Firth, Jill; Kinsey, Katharine; Edwards, Adrian; Brain, Kate E; Newcombe, Robert G; Nye, Alan; Pickles, Timothy; Hawthorne, Kamila; Elwyn, Glyn

    2014-04-07

    Despite policy interest, an ethical imperative, and evidence of the benefits of patient decision support tools, the adoption of shared decision making (SDM) in day-to-day clinical practice remains slow and is inhibited by barriers that include culture and attitudes; resources and time pressures. Patient decision support tools often require high levels of health and computer literacy. Option Grids are one-page evidence-based summaries of the available condition-specific treatment options, listing patients' frequently asked questions. They are designed to be sufficiently brief and accessible enough to support a better dialogue between patients and clinicians during routine consultations. This paper describes a study to assess whether an Option Grid for osteoarthritis of the knee (OA of the knee) facilitates SDM, and explores the use of Option Grids by patients disadvantaged by language or poor health literacy. This will be a stepped wedge exploratory trial involving 72 patients with OA of the knee referred from primary medical care to a specialist musculoskeletal service in Oldham. Six physiotherapists will sequentially join the trial and consult with six patients using usual care procedures. After a period of brief training in using the Option Grid, the same six physiotherapists will consult with six further patients using an Option Grid in the consultation. The primary outcome will be efficacy of the Option Grid in facilitating SDM as measured by observational scores using the OPTION scale. Comparisons will be made between patients who have received the Option Grid and those who received usual care. A Decision Quality Measure (DQM) will assess quality of decision making. The health literacy of patients will be measured using the REALM-R instrument. Consultations will be observed and audio-recorded. Interviews will be conducted with the physiotherapists, patients and any interpreters present to explore their views of using the Option Grid. Option Grids offer a potential solution to the barriers to implementing traditional decision aids into routine clinical practice. The study will assess whether Option Grids can facilitate SDM in day-to-day clinical practice and explore their use with patients disadvantaged by language or poor health literacy. Current Controlled Trials ISRCTN94871417.

  19. Population Pharmacokinetic Characteristics of Amikacin in Suspected Cases of Neonatal Sepsis in a Low-Resource African Setting: A Prospective Nonrandomized Single-Site Study

    Directory of Open Access Journals (Sweden)

    Seth K. Amponsah, PhD

    2017-01-01

    Conclusions: The V and half-life of amikacin in this cohort varied from that reported in non-African populations, and the high trough and low peak amikacin concentrations in both term and preterm neonates suggest strategies to optimize amikacin dosing are required in this population.

  20. Recruitment methods and costs for a randomized, placebo-controlled trial of chiropractic care for lumbar spinal stenosis: a single-site pilot study.

    Science.gov (United States)

    Cambron, Jerrilyn A; Dexheimer, Jennifer M; Chang, Mabel; Cramer, Gregory D

    2010-01-01

    The purpose of this article is to describe the methods for recruitment in a clinical trial on chiropractic care for lumbar spinal stenosis. This randomized, placebo-controlled pilot study investigated the efficacy of different amounts of total treatment dosage over 6 weeks in 60 volunteer subjects with lumbar spinal stenosis. Subjects were recruited for this study through several media venues, focusing on successful and cost-effective strategies. Included in our efforts were radio advertising, newspaper advertising, direct mail, and various other low-cost initiatives. Of the 1211 telephone screens, 60 responders (5.0%) were randomized into the study. The most successful recruitment method was radio advertising, generating more than 64% of the calls (776 subjects). Newspaper and magazine advertising generated approximately 9% of all calls (108 subjects), and direct mail generated less than 7% (79 subjects). The total direct cost for recruitment was $40 740 or $679 per randomized patient. The costs per randomization were highest for direct mail ($995 per randomization) and lowest for newspaper/magazine advertising ($558 per randomization). Success of recruitment methods may vary based on target population and location. Planning of recruitment efforts is essential to the success of any clinical trial. Copyright 2010 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  1. Interaction of water, alkyl hydroperoxide, and allylic alcohol with a single-site homogeneous Ti-Si epoxidation catalyst: A spectroscopic and computational study.

    Science.gov (United States)

    Urakawa, Atsushi; Bürgi, Thomas; Skrabal, Peter; Bangerter, Felix; Baiker, Alfons

    2005-02-17

    Tetrakis(trimethylsiloxy)titanium (TTMST, Ti(OSiMe3)4) possesses an isolated Ti center and is a highly active homogeneous catalyst in epoxidation of various olefins. The structure of TTMST resembles that of the active sites in some heterogeneous Ti-Si epoxidation catalysts, especially silylated titania-silica mixed oxides. Water cleaves the Ti-O-Si bond and deactivates the catalyst. An alkyl hydroperoxide, TBHP (tert-butyl hydroperoxide), does not cleave the Ti-O-Si bond, but interacts via weak hydrogen-bonding as supported by NMR, DOSY, IR, and computational studies. ATR-IR spectroscopy combined with computational investigations shows that more than one, that is, up to four, TBHP can undergo hydrogen-bonding with TTMST, leading to the activation of the O-O bond of TBHP. The greater the number of TBHP molecules that form hydrogen bonds to TTMST, the more electrophilic the O-O bond becomes, and the more active the complex is for epoxidation. An allylic alcohol, 2-cyclohexen-1-ol, does not interact strongly with TTMST, but the interaction is prominent when it interacts with the TTMST-TBHP complex. On the basis of the experimental and theoretical findings, a hydrogen-bond-assisted epoxidation mechanism of TTMST is suggested.

  2. Residues at a Single Site Differentiate Animal Cryptochromes from Cyclobutane Pyrimidine Dimer Photolyases by Affecting the Proteins' Preferences for Reduced FAD.

    Science.gov (United States)

    Xu, Lei; Wen, Bin; Wang, Yuan; Tian, Changqing; Wu, Mingcai; Zhu, Guoping

    2017-06-19

    Cryptochromes (CRYs) and photolyases belong to the cryptochrome/photolyase family (CPF). Reduced FAD is essential for photolyases to photorepair UV-induced cyclobutane pyrimidine dimers (CPDs) or 6-4 photoproducts in DNA. In Drosophila CRY (dCRY, a type I animal CRY), FAD is converted to the anionic radical but not to the reduced state upon illumination, which might induce a conformational change in the protein to relay the light signal downstream. To explore the foundation of these differences, multiple sequence alignment of 650 CPF protein sequences was performed. We identified a site facing FAD (Ala377 in Escherichia coli CPD photolyase and Val415 in dCRY), hereafter referred to as "site 377", that was distinctly conserved across these sequences: CPD photolyases often had Ala, Ser, or Asn at this site, whereas animal CRYs had Ile, Leu, or Val. The binding affinity for reduced FAD, but not the photorepair activity of E. coli photolyase, was dramatically impaired when replacing Ala377 with any of the three CRY residues. Conversely, in V415S and V415N mutants of dCRY, FAD was photoreduced to its fully reduced state after prolonged illumination, and light-dependent conformational changes of these mutants were severely inhibited. We speculate that the residues at site 377 play a key role in the different preferences of CPF proteins for reduced FAD, which differentiate animal CRYs from CPD photolyases. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. "Hydro-metathesis" of olefins: A catalytic reaction using a bifunctional single-site tantalum hydride catalyst supported on fibrous silica (KCC-1) nanospheres

    KAUST Repository

    Polshettiwar, Vivek

    2011-02-18

    Tantalizing hydrocarbons: Tantalum hydride supported on fibrous silica nanospheres (KCC-1) catalyzes, in the presence of hydrogen, the direct conversion of olefins into alkanes that have higher and lower numbers of carbon atoms (see scheme). This catalyst shows remarkable catalytic activity and stability, with excellent potential of regeneration. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Single-Site VO x Moieties Generated on Silica by Surface Organometallic Chemistry: A Way To Enhance the Catalytic Activity in the Oxidative Dehydrogenation of Propane

    KAUST Repository

    Barman, Samir

    2016-07-26

    We report here an accurate surface organometallic chemistry (SOMC) approach to propane oxidative dehydrogenation (ODH) using a μ2-oxo-bridged, bimetallic [V2O4(acac)2] (1) (acac = acetylacetonate anion) complex as a precursor. The identity and the nuclearity of the product of grafting and of the subsequent oxidative treatment have been systematically studied by means of FT-IR, Raman, solid-state (SS) NMR, UV-vis DRS, EPR and EXAFS spectroscopies. We show that the grafting of 1 on the silica surface under a rigorous SOMC protocol and the subsequent oxidative thermal treatment lead exclusively to well-defined and isolated monovanadate species. The resulting material has been tested for the oxidative dehydrogenation of propane in a moderate temperature range (400-525 °C) and compared with that of silica-supported vanadium catalysts prepared by the standard impregnation technique. The experimental results show that the catalytic activity in propane ODH is strongly upgraded by the degree of isolation of the VOx species that can be achieved by employing the SOMC protocol. © 2016 American Chemical Society.

  5. Conversion of actual flue gas CO 2 via cycloaddition to propylene oxide catalyzed by a single-site, recyclable zirconium catalyst

    KAUST Repository

    Kelly, Michael J.

    2017-06-12

    A reusable zirconium-based catalyst for the cycloaddition of CO2 to propylene oxide (PO) was prepared by the surface organometallic chemistry (SOMC) methodology. Accordingly, well-defined amounts of the ZrCl4·(OEt2)2 precursor were grafted on the surface of silica dehydroxylated at 700°C (SiO2-700) and at 200°C (SiO2-200) in order to afford surface coordination compounds with different podality and chemical environment. The identity of the surface complexes was thoroughly investigated by FT-IR, elemental microanalysis and solid state NMR and applied as a recoverable and reusable heterogeneous catalyst for the title reaction using pure CO2 and flue gas samples from a cement factory. The observed catalytic activity for the isolated zirconium complexes is rationalized by means of systematic DFT calculations.

  6. Single Site Silica Supported Tetramethyl Niobium by the SOMC Strategy: Synthesis, Characterization and Structure-Activity Relationship in Ethylene Oligomerization Reaction

    KAUST Repository

    Hamieh, Ali Imad Ali

    2017-06-06

    Silica supported Tetramethyl niobium complex [(≡SiO)NbMe4] 2 has been isolated by surface alkylation of [(≡SiO-)NbCl3Me] 1 with dimethyl zinc in pentane. 1 can be easily synthesized by grafting of NbCl3Me2 on to the surface of partially dehydroxylated silica by the SOMC strategy. Precise structural analysis was carried out by the FTIR, advance solid state NMR, elemental analysis and mass balance techniques (gas quantification after treating 2 with degassed water) . Complex 1 was found to be active in the ethylene oligomerization to produce up to C30, whereas to our surprise complex 2 selectively dimerizes ethylene into 1-butene in the absence of a co-catalyst at the same conversion levels.

  7. Stabilization of bacterially expressed erythropoietin by single site-specific introduction of short branched PEG chains at naturally occurring glycosylation sites.

    Science.gov (United States)

    Hoffmann, E; Streichert, K; Nischan, N; Seitz, C; Brunner, T; Schwagerus, S; Hackenberger, C P R; Rubini, M

    2016-05-24

    The covalent attachment of polyethylene glycol (PEG) to therapeutic proteins can improve their physicochemical properties. In this work we utilized the non-natural amino acid p-azidophenylalanine (pAzF) in combination with the chemoselective Staudinger-phosphite reaction to install branched PEG chains to recombinant unglycosylated erythropoietin (EPO) at each single naturally occurring glycosylation site. PEGylation with two short 750 or 2000 Da PEG units at positions 24, 38, or 83 significantly decreased unspecific aggregation and proteolytic degradation while biological activity in vitro was preserved or even increased in comparison to full-glycosylated EPO. This site-specific bioconjugation approach permits to analyse the impact of PEGylation at single positions. These results represent an important step towards the engineering of site-specifically modified EPO variants from bacterial expression with increased therapeutic efficacy.

  8. HuR binds to a single site on the C/EBPβ mRNA of 3T3-L1 adipocytes

    International Nuclear Information System (INIS)

    Jones, Heath; Carver, Melinda; Pekala, Phillip H.

    2007-01-01

    HuR is a ligand for nuclear mRNAs containing adenylate-uridylate rich elements in the 3'-untranslated region. Once bound to the mRNA, HuR is recognized by adapter proteins which then facilitate nuclear export of the complex. In the cytosol HuR is thought to function to control stability and translation of its ligand message. In the 3T3-L1 cells HuR is constitutively expressed and localized predominantly to the nucleus in the preadipocytes. However within 30 min of exposure to the differentiation stimulus, the HuR content in the cytosol increases consistent with HuR regulating the availability of relevant mRNAs for translation. Using in vitro RNA gel shifts, we have demonstrated that the C/EBPβ message is a ligand for HuR and that the single binding site is an adenylate-uridylate rich element in the 3'-untranslated region

  9. Complicated Fermi-type vibronic resonance: Untangling of the single-site quasi-line fluorescence excitation spectra of a methylated dibenzoporphin

    International Nuclear Information System (INIS)

    Arabei, S.M.; Kuzmitsky, V.A.; Solovyov, K.N.

    2008-01-01

    The quasi-line low-temperature (4.2 K) fluorescence excitation spectra of 2,3,12,13-tetramethyldibenzo[g,q]porphin introduced into an n-octane matrix have been measured in the range of the S 2 0 electronic transition at selective fluorescence monitoring for the two main types of impurity centers (sites). A characteristic feature of these spectra is that a conglomerate of quasi-lines - a structured complex band - is observed instead of one 0-0 quasi-line of the S 2 0 transition. In this band, the intensity distributions for the two main sites considerably differ from each other. The occurrence of such conglomerates is interpreted as a result of nonadiabatic vibrational-electronic interaction between the vibronic S 2 and S 1 states (the complex vibronic analogue of the Fermi resonance). The frequencies and intensities of individual transitions determined from the deconvolution of complex conglomerates are used as the initial data for solving the inverse spectroscopic problem: the determination of the unperturbed electronic and vibrational levels of states involved in the resonance and the vibronic-interaction matrix elements between them. This problem is solved with a method developed previously. The experimental results and their analysis are compared to the analogous data obtained earlier for meso-tetraazaporphin and meso-tetrapropylporphin. The energy intervals between the S 2 and S 1 electronic levels (ΔE S 2 S 1 ) of the two main types of impurity centers formed by molecules of a given porphyrin in the crystal matrix are found to significantly differ from each other, the values of this difference (δΔE S 2 S 1 ) being considerably greater for tetramethyldibenzoporphin, δΔE S 2 S 1 =228cm -1 , than for the two other porphyrins. At the same time, the energies of the unperturbed vibrational states of the S 1 electronic level participating in the resonance are very close to each other for these two sites

  10. "Hydro-metathesis" of olefins: A catalytic reaction using a bifunctional single-site tantalum hydride catalyst supported on fibrous silica (KCC-1) nanospheres

    KAUST Repository

    Polshettiwar, Vivek; Thivolle-Cazat, Jean; Taoufik, Mostafa; Stoffelbach, Franç ois; Norsic, Sé bastien; Basset, Jean-Marie

    2011-01-01

    Tantalizing hydrocarbons: Tantalum hydride supported on fibrous silica nanospheres (KCC-1) catalyzes, in the presence of hydrogen, the direct conversion of olefins into alkanes that have higher and lower numbers of carbon atoms (see scheme). This catalyst shows remarkable catalytic activity and stability, with excellent potential of regeneration. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. A single site for N-linked glycosylation in the envelope glycoprotein of feline immunodeficiency virus modulates the virus-receptor interaction

    Directory of Open Access Journals (Sweden)

    Samman Ayman

    2008-08-01

    Full Text Available Abstract Feline immunodeficiency virus (FIV targets helper T cells by attachment of the envelope glycoprotein (Env to CD134, a subsequent interaction with CXCR4 then facilitating the process of viral entry. As the CXCR4 binding site is not exposed until CD134-binding has occurred then the virus is protected from neutralising antibodies targeting the CXCR4-binding site on Env. Prototypic FIV vaccines based on the FL4 strain of FIV contain a cell culture-adapted strain of FIV Petaluma, a CD134-independent strain of FIV that interacts directly with CXCR4. In addition to a characteristic increase in charge in the V3 loop homologue of FIVFL4, we identified two mutations in potential sites for N-linked glycosylation in the region of FIV Env analogous to the V1–V2 region of HIV and SIV Env, T271I and N342Y. When these mutations were introduced into the primary GL8 and CPG41 strains of FIV, the T271I mutation was found to alter the nature of the virus-CD134 interaction; primary viruses carrying the T271I mutation no longer required determinants in cysteine-rich domain (CRD 2 of CD134 for viral entry. The T271I mutation did not confer CD134-independent infection upon GL8 or CPG41, nor did it increase the affinity of the CXCR4 interaction, suggesting that the principal effect was targeted at reducing the complexity of the Env-CD134 interaction.

  12. Single-Site VO x Moieties Generated on Silica by Surface Organometallic Chemistry: A Way To Enhance the Catalytic Activity in the Oxidative Dehydrogenation of Propane

    KAUST Repository

    Barman, Samir; Maity, Niladri; Bhatte, Kushal; Ould-Chikh, Samy; Dachwald, Oliver; Haeß ner, Carmen; Saih, Youssef; Abou-Hamad, Edy; Llorens, Isabelle; Hazemann, Jean-Louis; Kö hler, Klaus; D’ Elia, Valerio; Basset, Jean-Marie

    2016-01-01

    We report here an accurate surface organometallic chemistry (SOMC) approach to propane oxidative dehydrogenation (ODH) using a μ2-oxo-bridged, bimetallic [V2O4(acac)2] (1) (acac = acetylacetonate anion) complex as a precursor. The identity and the nuclearity of the product of grafting and of the subsequent oxidative treatment have been systematically studied by means of FT-IR, Raman, solid-state (SS) NMR, UV-vis DRS, EPR and EXAFS spectroscopies. We show that the grafting of 1 on the silica surface under a rigorous SOMC protocol and the subsequent oxidative thermal treatment lead exclusively to well-defined and isolated monovanadate species. The resulting material has been tested for the oxidative dehydrogenation of propane in a moderate temperature range (400-525 °C) and compared with that of silica-supported vanadium catalysts prepared by the standard impregnation technique. The experimental results show that the catalytic activity in propane ODH is strongly upgraded by the degree of isolation of the VOx species that can be achieved by employing the SOMC protocol. © 2016 American Chemical Society.

  13. Conversion of actual flue gas CO 2 via cycloaddition to propylene oxide catalyzed by a single-site, recyclable zirconium catalyst

    KAUST Repository

    Kelly, Michael J.; Barthel, Alexander; Maheu, Clement; Sodpiban, Ounjit; Dega, Frank-Blondel; Vummaleti, Sai V.C.; Abou-Hamad, Edy; Pelletier, Jeremie; Cavallo, Luigi; D'Elia, Valerio; Basset, Jean-Marie

    2017-01-01

    A reusable zirconium-based catalyst for the cycloaddition of CO2 to propylene oxide (PO) was prepared by the surface organometallic chemistry (SOMC) methodology. Accordingly, well-defined amounts of the ZrCl4·(OEt2)2 precursor were grafted on the surface of silica dehydroxylated at 700°C (SiO2-700) and at 200°C (SiO2-200) in order to afford surface coordination compounds with different podality and chemical environment. The identity of the surface complexes was thoroughly investigated by FT-IR, elemental microanalysis and solid state NMR and applied as a recoverable and reusable heterogeneous catalyst for the title reaction using pure CO2 and flue gas samples from a cement factory. The observed catalytic activity for the isolated zirconium complexes is rationalized by means of systematic DFT calculations.

  14. Single Site Silica Supported Tetramethyl Niobium by the SOMC Strategy: Synthesis, Characterization and Structure-Activity Relationship in Ethylene Oligomerization Reaction

    KAUST Repository

    Hamieh, Ali Imad Ali; Dey, Raju; Nekoueishahraki, Bijan; Samantaray, Manoja; Chen, Yin; Abou-Hamad, Edy; Basset, Jean-Marie

    2017-01-01

    Silica supported Tetramethyl niobium complex [(≡SiO)NbMe4] 2 has been isolated by surface alkylation of [(≡SiO-)NbCl3Me] 1 with dimethyl zinc in pentane. 1 can be easily synthesized by grafting of NbCl3Me2 on to the surface of partially dehydroxylated silica by the SOMC strategy. Precise structural analysis was carried out by the FTIR, advance solid state NMR, elemental analysis and mass balance techniques (gas quantification after treating 2 with degassed water) . Complex 1 was found to be active in the ethylene oligomerization to produce up to C30, whereas to our surprise complex 2 selectively dimerizes ethylene into 1-butene in the absence of a co-catalyst at the same conversion levels.

  15. Umbilical KeyPort bilateral laparoscopic orchiectomy in patient with complete androgen insensitivity syndrome

    Directory of Open Access Journals (Sweden)

    Felipe P. Andrade

    2012-10-01

    Full Text Available MAIN FINDINGS: A 22-year-old woman with complete androgen insensitivity syndrome (CAIS presenting with primary amenorrhea and normal female external genitalia was referred for laparoscopic gonadectomy. She had been diagnosed several years earlier but was reluctant to undergo surgery. CASE HYPOTHESIS: Diagnosis of this X-linked recessive inherited syndrome characterizes by disturbance of virilization in males with an AR mutation, XY karyotipe, female genitalia and severely undescended testis with risk of malignization. The optimal time to orchidectomy is not settled; neither the real risk of malignancy in these patients. Early surgery impacts development of a complete female phenotype, with enlargement of the breasts. Based on modern diagnostic imaging using DCE-MRI and surgical technology with single port laparoscopic access we hypothesize that the optimum time for gonadectomy is not at the time of diagnosis, but once feminization has completed. PROMISING FUTURE IMPLICATIONS: An umbilical laparoendoscopic single-site access for bilateral gonadectomy appears to be the first choice approach as leaves no visible incision and diminishes the psychological impact of surgery in a patient with CAIS absolutely reassured as female. KeyPort, a single port access with duo-rotate instruments developed by Richard Wolf facilitates this surgery and allows excellent cosmetic results.

  16. Two-Port Laparoscopic Reconstructive Surgery of the Urinary Tract with Reusable Umbilical System (Hybrid Less): A Proof of Concept Study.

    Science.gov (United States)

    Angulo, Javier C; Pérez, Sergio; García-Tello, Ana; Redondo, Cristina; Meilán, Elisa; Arance, Ignacio

    2016-01-01

    We compared perioperative results and complications of reconstructive surgery of the urinary tract performed using a multichannel platform through the umbilicus and one additional 3.5-mm with a cohort of patients simultaneously treated with conventional 4-port laparoscopy. Matched-pair study comparing perioperative outcomes, postoperative visual analogue pain scale (VAPS) and morbidity of 2-port (n = 20) and 4-port (n = 10) laparoscopic reconstructive urological surgery. Preoperative and perioperative data compared included demographics, type of surgery, operative time, blood loss, decrease in serum hemoglobin, operative complications, length of stay and postoperative complications according to Clavien-Dindo classification. There was no significant difference between groups regarding age, gender, body mass index, American Society of Anesthesiologists score, type of surgery, operative time, operative complications and intraoperative or postoperative transfusion. Estimated blood loss was lower using reduced-port approach. VAPS at postoperative day one was significantly lower for 2-port approach and so was the length of stay. Patient satisfaction with the wound was higher for 2-port surgery. Differences were not observed in number and severity of postoperative complications. Urological reconstructive operations can be safely performed using the hybrid laparoendoscopic single-site umbilical approach, resulting in lower blood loss, higher patient satisfaction and lower postoperative pain, which also facilitate earlier hospital discharge, than the same reconstructive procedures performed through multiport conventional laparoscopy. © 2016 S. Karger AG, Basel.

  17. Robotic single port cholecystectomy: current data and future perspectives.

    Science.gov (United States)

    Angelou, Anastasios; Skarmoutsos, Athanasios; Margonis, Georgios A; Moris, Demetrios; Tsigris, Christos; Pikoulis, Emmanouil

    2017-04-01

    Minimally invasive techniques are used more and more frequently. Since conventional laparoscopic approach has been the gold standard, surgeons in their effort to further reduce the invasiveness of conventional laparoscopic cholecystectomy have adopted Single Incision approach. The widespread adoption of robotics has led to the inevitable hybridization of robotic technology with laparoendoscopic single-site surgery (LESS). As a result, employment of the da Vinci surgical system may allow greater surgical maneuverability, improving ergonomics. A review of the English literature was conducted to evaluate all robotic single port cholecystectomy performed till today. Demographic data, operative parameters, postoperative outcomes and materials used for the operation were collected and assessed. A total of 12 studies, including 501 patients were analyzed. Demographics and clinical characteristics of the patients was heterogeneous, but in most studies a mean BMI port cholecystectomy is a safe and feasible alternative to conventional multiport laparoscopic or manual robotic approach. However, current data do not suggest a superiority of robotic SILC over other established methods.

  18. Consensus statement of the consortium for LESS cholecystectomy.

    Science.gov (United States)

    Ross, Sharona; Rosemurgy, Alexander; Albrink, Michael; Choung, Edward; Dapri, Giovanni; Gallagher, Scott; Hernandez, Jonathan; Horgan, Santiago; Kelley, William; Kia, Michael; Marks, Jeffrey; Martinez, Jose; Mintz, Yoav; Oleynikov, Dmitry; Pryor, Aurora; Rattner, David; Rivas, Homero; Roberts, Kurt; Rubach, Eugene; Schwaitzberg, Steven; Swanstrom, Lee; Sweeney, John; Wilson, Erik; Zemon, Harry; Zundel, Natan

    2012-10-01

    Many surgeons attempting Laparo-Endoscopic Single Site (LESS) cholecystectomy have found the operation difficult, which is inconsistent with our experience. This article is an attempt to promote a standardized approach that we feel surgeons with laparoscopic skills can perform safely and efficiently. This is a four-trocar approach consistent with the four incisions utilized in conventional laparoscopic cholecystectomy. After administration of general anesthesia, marcaine is injected at the umbilicus and a 12-mm vertical incision is made through the already existing anatomical scar of the umbilicus. A single four-trocar port is inserted. A 5-mm deflectable-tip laparoscope is placed through the trocar at the 8 o'clock position, a bariatric length rigid grasper is inserted through the trocar at the 4 o'clock position (to grasp the fundus), and a rigid bent grasper is placed through the 10-mm port (to grasp the infundibulum). This arrangement of the instruments promotes minimal internal and external instrument clashing with simultaneous optimization of the operative view. This orientation allows retraction of the gallbladder in a cephalad and lateral direction, development of a window between the gallbladder and the liver which promotes the "critical view" of the cystic duct and artery, and provides triangulation with excellent visualization of the operative field. The operation is concluded with diaphragmatic irrigation of marcaine solution to minimize postoperative pain. Standardization of LESS cholecystectomy will speed adoption, reduce intraoperative complications, and improve the efficiency and safety of the approach.

  19. New trends in minimally invasive urological surgery

    Directory of Open Access Journals (Sweden)

    Prabhakar Rajan

    2009-10-01

    Full Text Available Purpose: The perceived benefits of minimally-invasive surgery include less postoperative pain, shorter hospitalization, reduced morbidity and better cosmesis while maintaining diagnostic accuracy and therapeutic outcome. We review the new trends in minimally-invasive urological surgery. Materials and method: We reviewed the English language literature using the National Library of Medicine database to identify the latest technological advances in minimally-invasive surgery with particular reference to urology. Results: Amongst other advances, studies incorporating needlescopic surgery, laparoendoscopic single-site surgery , magnetic anchoring and guidance systems, natural orifice transluminal endoscopic surgery and flexible robots were considered of interest. The results from initial animal and human studies are also outlined. Conclusion: Minimally-invasive surgery continues to evolve to meet the demands of the operators and patients. Many novel technologies are still in the testing phase, whilst others have entered clinical practice. Further evaluation is required to confirm the safety and efficacy of these techniques and validate the published reports.

  20. Miniature surgical robots in the era of NOTES and LESS: dream or reality?

    Science.gov (United States)

    Zygomalas, Apollon; Kehagias, Ioannis; Giokas, Konstantinos; Koutsouris, Dimitrios

    2015-02-01

    Laparoscopy is an established method for the treatment of numerous surgical conditions. Natural orifice transluminal endoscopic surgery (NOTES) is a novel surgical technique that uses the natural orifices of the human body as entrances to the abdominal cavity. An alternative concept of minimally invasive approach to the abdominal cavity is to insert all the laparoscopic instruments through ports using a single small incision on the abdominal wall. A suggested name for this technique is laparoendoscopic single-site surgery (LESS). Considering the technical difficulties in NOTES and LESS and the progress in informatics and robotics, the use of robots seems ideal. The aim of this study is to investigate if there is at present, a realistic possibility of using miniature robots in NOTES or LESS in daily clinical practice. An up-to-date review on in vivo surgical miniature robots is made. A Web-based research of the English literature up to March 2013 using PubMed, Scopus, and Google Scholar as search engines was performed. The development of in vivo miniature robots for use in NOTES or LESS is a reality with great advancements, potential advantages, and possible application in minimally invasive surgery in the future. However, true totally NOTES or LESS procedures on humans using miniature robots either solely or as assistance, remain a dream at present. © The Author(s) 2014.

  1. In Silico Investigation of a Surgical Interface for Remote Control of Modular Miniature Robots in Minimally Invasive Surgery

    Directory of Open Access Journals (Sweden)

    Apollon Zygomalas

    2014-01-01

    Full Text Available Aim. Modular mini-robots can be used in novel minimally invasive surgery techniques like natural orifice transluminal endoscopic surgery (NOTES and laparoendoscopic single site (LESS surgery. The control of these miniature assistants is complicated. The aim of this study is the in silico investigation of a remote controlling interface for modular miniature robots which can be used in minimally invasive surgery. Methods. The conceptual controlling system was developed, programmed, and simulated using professional robotics simulation software. Three different modes of control were programmed. The remote controlling surgical interface was virtually designed as a high scale representation of the respective modular mini-robot, therefore a modular controlling system itself. Results. With the proposed modular controlling system the user could easily identify the conformation of the modular mini-robot and adequately modify it as needed. The arrangement of each module was always known. The in silico investigation gave useful information regarding the controlling mode, the adequate speed of rearrangements, and the number of modules needed for efficient working tasks. Conclusions. The proposed conceptual model may promote the research and development of more sophisticated modular controlling systems. Modular surgical interfaces may improve the handling and the dexterity of modular miniature robots during minimally invasive procedures.

  2. Innovations in robotic surgery.

    Science.gov (United States)

    Gettman, Matthew; Rivera, Marcelino

    2016-05-01

    Developments in robotic surgery have continued to advance care throughout the field of urology. The purpose of this review is to evaluate innovations in robotic surgery over the past 18 months. The release of the da Vinci Xi system heralded an improvement on the Si system with improved docking, the ability to further manipulate robotic arms without clashing, and an autofocus universal endoscope. Robotic simulation continues to evolve with improvements in simulation training design to include augmented reality in robotic surgical education. Robotic-assisted laparoendoscopic single-site surgery continues to evolve with improvements on technique that allow for tackling previously complex pathologic surgical anatomy including urologic oncology and reconstruction. Last, innovations of new surgical platforms with robotic systems to improve surgeon ergonomics and efficiency in ureteral and renal surgery are being applied in the clinical setting. Urologic surgery continues to be at the forefront of the revolution of robotic surgery with advancements in not only existing technology but also creation of entirely novel surgical systems.

  3. A single institution's experience with more than 500 laparoscopic Heller myotomies for achalasia.

    Science.gov (United States)

    Rosemurgy, Alexander S; Morton, Connor A; Rosas, Melissa; Albrink, Michael; Ross, Sharona B

    2010-05-01

    Long-term symptom relief and patient satisfaction after Heller myotomy are being reported. Herein, we report the largest experience of laparoscopic Heller myotomy for the treatment of achalasia. Since 1992, 505 patients have been prospectively followed after laparoscopic Heller myotomy. Until 2004, concomitant fundoplication was undertaken for a patulous hiatus, a large hiatal hernia, or to buttress the repair of an esophagotomy, then concomitant fundoplication became routinely applied. More recently, laparo-endoscopic single site (LESS) Heller myotomy has been performed when possible to improve cosmesis. Before and after myotomy, patients scored their symptoms. Before myotomy, 60% of patients underwent endoscopic therapy; of these patients, 27% had Botox (Allergan) therapy alone, 52% underwent dilation therapy alone, and 21% had both. Esophagotomy occurred in 7% of patients. Concomitant diverticulectomy was undertaken in 7%, fundoplication was performed in 59%, and LESS Heller myotomy was done in 12%. Median length of stay was 1 day. With mean follow-up at 31 months, the severity of all symptoms improved significantly. After myotomy, 95% experienced symptoms less than once per week, 86% believed their outcome is satisfying or better, and 92% would undergo myotomy again, if necessary. Symptoms after myotomy are similar with or without fundoplication and regardless of the laparoscopic approach used. Laparoscopic Heller myotomy safely and durably relieves symptoms of dysphagia. Confinement is short and satisfaction is very high. Relief of esophageal obstruction is paramount; the approach used or the application of a fundoplication has a lesser impact. Laparoscopic Heller myotomy, preferably with anterior fundoplication using a single site laparoscopic approach, is strongly encouraged for patients with symptomatic achalasia and is efficacious even after failures of dilation and/or Botox therapy. Copyright 2010 American College of Surgeons. Published by Elsevier Inc

  4. Advantages of robotics in benign gynecologic surgery.

    Science.gov (United States)

    Truong, Mireille; Kim, Jin Hee; Scheib, Stacey; Patzkowsky, Kristin

    2016-08-01

    The purpose of this article is to review the literature and discuss the advantages of robotics in benign gynecologic surgery. Minimally invasive surgery has become the preferred route over abdominal surgery. The laparoscopic or robotic approach is recommended when vaginal surgery is not feasible. Thus far, robotic gynecologic surgery data have demonstrated feasibility, safety, and equivalent clinical outcomes in comparison with laparoscopy and better clinical outcomes compared with laparotomy. Robotics was developed to overcome challenges of laparoscopy and has led to technological advantages such as improved ergonomics, visualization with three-dimensional capabilities, dexterity and range of motion with instrument articulation, and tremor filtration. To date, applications of robotics in benign gynecology include hysterectomy, myomectomy, endometriosis surgery, sacrocolpopexy, adnexal surgery, tubal reanastomosis, and cerclage. Though further data are needed, robotics may provide additional benefits over other approaches in the obese patient population and in higher complexity cases. Challenges that arose in the earlier adoption stage such as the steep learning curve, costs, and operative times are becoming more optimized with greater experience, with implementation of robotics in high-volume centers and with improved training of surgeons and robotic teams. Robotic laparoendoscopic single-site surgery, albeit still in its infancy where technical advantages compared with laparoscopic single-site surgery are still unclear, may provide a cost-reducing option compared with multiport robotics. The cost may even approach that of laparoscopy while still conferring similar perioperative outcomes. Advances in robotic technology such as the single-site platform and telesurgery, have the potential to revolutionize the field of minimally invasive gynecologic surgery. Higher quality evidence is needed to determine the advantages and disadvantages of robotic surgery in benign

  5. Single site mutations in the hetero-oligomeric Mrp antiporter from alkaliphilic Bacillus pseudofirmus OF4 that affect Na+/H+ antiport activity, sodium exclusion, individual Mrp protein levels, or Mrp complex formation.

    Science.gov (United States)

    Morino, Masato; Natsui, Shinsuke; Ono, Tomohiro; Swartz, Talia H; Krulwich, Terry A; Ito, Masahiro

    2010-10-01

    Mrp systems are widely distributed and structurally complex cation/proton antiporters. Antiport activity requires hetero-oligomeric complexes of all six or seven hydrophobic Mrp proteins (MrpA-MrpG). Here, a panel of site-directed mutants in conserved or proposed motif residues was made in the Mrp Na(+)(Li(+))/H(+) antiporter from an alkaliphilic Bacillus. The mutant operons were expressed in antiporter-deficient Escherichia coli KNabc and assessed for antiport properties, support of sodium resistance, membrane levels of each Mrp protein, and presence of monomeric and dimeric Mrp complexes. Antiport did not depend on a VFF motif or a conserved tyrosine pair, but a role for a conserved histidine in a potential quinone binding site of MrpA was supported. The importance of several acidic residues for antiport was confirmed, and the importance of additional residues was demonstrated (e.g. three lysine residues conserved across MrpA, MrpD, and membrane-bound respiratory Complex I subunits (NuoL/M/N)). The results extended indications that MrpE is required for normal membrane levels of other Mrp proteins and for complex formation. Moreover, mutations in several other Mrp proteins lead to greatly reduced membrane levels of MrpE. Thus, changes in either of the two Mrp modules, MrpA-MrpD and MrpE-MrpG, influence the other. Two mutants, MrpB-P37G and MrpC-Q70A, showed a normal phenotype but lacked the MrpA-MrpG monomeric complex while retaining the dimeric hetero-oligomeric complex. Finally, MrpG-P81A and MrpG-P81G mutants exhibited no antiport activity but supported sodium resistance and a low [Na(+)](in). Such mutants could be used to screen hypothesized but uncharacterized sodium efflux functions of Mrp apart from Na(+) (Li(+))/H(+) antiport.

  6. Single Site Mutations in the Hetero-oligomeric Mrp Antiporter from Alkaliphilic Bacillus pseudofirmus OF4 That Affect Na+/H+ Antiport Activity, Sodium Exclusion, Individual Mrp Protein Levels, or Mrp Complex Formation*

    OpenAIRE

    Morino, Masato; Natsui, Shinsuke; Ono, Tomohiro; Swartz, Talia H.; Krulwich, Terry A.; Ito, Masahiro

    2010-01-01

    Mrp systems are widely distributed and structurally complex cation/proton antiporters. Antiport activity requires hetero-oligomeric complexes of all six or seven hydrophobic Mrp proteins (MrpA–MrpG). Here, a panel of site-directed mutants in conserved or proposed motif residues was made in the Mrp Na+(Li+)/H+ antiporter from an alkaliphilic Bacillus. The mutant operons were expressed in antiporter-deficient Escherichia coli KNabc and assessed for antiport properties, support of sodium resista...

  7. Comparison of bromfenac 0.09% QD to nepafenac 0.1% TID after cataract surgery: pilot evaluation of visual acuity, macular volume, and retinal thickness at a single site

    Directory of Open Access Journals (Sweden)

    Cable M

    2012-07-01

    Full Text Available Melissa CableDiscover Vision Centers, Independence, MO, USAPurpose: The purpose of this study was to investigate the clinical outcomes of bromfenac ophthalmic solution 0.09% once daily (QD and nepafenac 0.1% ophthalmic suspension three times daily following cataract extraction with posterior chamber intraocular lens implantation, specifically looking at any differences in Early Treatment Diabetic Retinopathy Study visual acuities, macular volume, and/or retinal thickness changes.Methods: Subjects were randomly assigned to receive either bromfenac (n = 10 QD or nepafenac (n = 10 three times daily. Dosing began 3 days before cataract surgery, continuing to day 21 postsurgery. In addition to the investigated nonsteroidal antiinflammatory drug regimen, all subjects received antiinfective intraoperative and postoperative standard of care. Subjects were followed at 1 day and 1, 3, and 6 weeks postoperatively. Study visit assessments included best-corrected visual acuity, biomicroscopy, summed ocular inflammation score (anterior chamber cells and flare grading, intraocular pressure measurement, adverse event recording, and concomitant medication review. Optical coherence tomography was performed at 1, 3, and 6 weeks.Results: Both treatment groups had similar baseline measurements. Outcomes for mean letters read (P = 0.318, mean change in macular volume (P = 0.665, and retinal thickness (P = 0.552 were not statistically different between the groups from baseline through week six, although independently only the bromfenac group demonstrated a statistically significant improvement in letters gained from baseline to week six (P = 0.040. In the same time period, mean macular volume and retinal thickening worsened in the nepafenac group, demonstrating a statistically significant increase (P = 0.006 at week six for macular volume when compared to baseline. One subject in the nepafenac group experienced recurrent inflammation at week six, was unmasked, and then rescued with bromfenac 0.09% QD and difluprednate 0.05% QD.Conclusion: Both bromfenac and nepafenac resulted in positive clinical outcomes of Early Treatment Diabetic Retinopathy Study visual acuities. Postoperative measurements of macular volume and retinal thickness of bromfenac subjects showed a trend toward improved vision, less retinal thickening, and more stable macular volumes overall.Keywords: NSAIDs, phacoemulsification, inflammation, cataract, macular volume, retinal thickness

  8. Records of shallow-water marine invertebrates from French Frigate Shoals, Northwestern Hawaiian Islands with a note on nonindigenous species from NOWRAMP 2000 surveys at 39 sites and a 2002-03 survey at a single site (NODC Accession 0001083)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In September of 2000, the Northwest Hawaiian Islands Rapid Assessment and Monitoring Program (NOW-RAMP) Expedition surveyed French Frigate Shoals (FFS) and a number...

  9. Heterolytic cleavage of ammonia N-H bond by bifunctional activation in silica-grafted single site Ta(V) imido amido surface complex. Importance of the outer sphere NH3 assistance

    KAUST Repository

    Gouré, Eric

    2011-01-01

    Ammonia N-H bond is cleaved at room temperature by the silica-supported tantalum imido amido complex [(≡SiO)2Ta(NH)(-NH2)], 2, if excess ammonia is present, but requires 150 °C to achieve the same reaction if only one equivalent NH3 is added to 2. MAS solid-state 15N NMR and in situ IR spectroscopic studies of the reaction of either 15N or 2H labeled ammonia with 2 show that initial coordination of the ammonia is followed by scrambling of either 15N or 2H among ammonia, amido and imido groups. Density functional theory (DFT) calculations with a cluster model [{(μ-O)[(H3SiO) 2SiO]2}Ta(NH)(-NH2)(NH3)], 2 q·NH3, show that the intramolecular H transfer from Ta-NH2 to TaNH is ruled out, but the H transfers from the coordinated ammonia to the amido and imido groups have accessible energy barriers. The energy barrier for the ammonia N-H activation by the Ta-amido group is energetically preferred relative to the Ta-imido group. The importance of excess NH3 for getting full isotope scrambling is rationalized by an outer sphere assistance of ammonia acting as proton transfer agent, which equalizes the energy barriers for H transfer from coordinated ammonia to the amido and imido groups. In contrast, additional coordinated ammonia does not favor significantly the H transfer. These results rationalize the experimental conditions used. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2011.

  10. From single-site tantalum complexes to nanoparticles of TaxNy and TaOxNy supported on silica: elucidation of synthesis chemistry by dynamic nuclear polarization surface enhanced NMR spectroscopy and X-ray absorption spectroscopy

    KAUST Repository

    Mohandas, Janet Chakkamadathil

    2017-06-08

    Air-stable catalysts consisting of tantalum nitride nanoparticles represented as a mixture of TaxNy and TaOxNy with diameters in the range of 0.5 to 3 nm supported on highly dehydroxylated silica were synthesized from TaMe5 (Me = methyl) and dimeric Ta-2(OMe)(10) with guidance by the principles of surface organometallic chemistry (SOMC). Characterization of the supported precursors and the supported nanoparticles formed from them was carried out by IR, NMR, UV-Vis, extended X-ray absorption fine structure, and X-ray photoelectron spectroscopies complemented with XRD and high-resolution TEM, with dynamic nuclear polarization surface enhanced NMR spectroscopy being especially helpful by providing enhanced intensities of the signals of H-1, C-13, Si-29, and N-15 at their natural abundances. The characterization data provide details of the synthesis chemistry, including evidence of (a) O-2 insertion into Ta-CH3 species on the support and (b) a binuclear to mononuclear transformation of species formed from Ta-2(OMe)(10) on the support. A catalytic test reaction, cyclooctene epoxidation, was used to probe the supported nanoparticles, with 30% H2O2 serving as the oxidant. The catalysts gave selectivities up to 98% for the epoxide at conversions as high as 99% with a 3.4 wt% loading of Ta present as TaxNy/TaOxNy.

  11. From single-site tantalum complexes to nanoparticles of TaxNy and TaOxNy supported on silica: elucidation of synthesis chemistry by dynamic nuclear polarization surface enhanced NMR spectroscopy and X-ray absorption spectroscopy

    KAUST Repository

    Mohandas, Janet Chakkamadathil; Abou-Hamad, Edy; Callens, Emmanuel; Samantaray, Manoja; Gajan, David; Gurinov, Andrei; Ma, Tao; Ould-Chikh, Samy; Hoffman, Adam S.; Gates, Bruce C.; Basset, Jean-Marie

    2017-01-01

    Air-stable catalysts consisting of tantalum nitride nanoparticles represented as a mixture of TaxNy and TaOxNy with diameters in the range of 0.5 to 3 nm supported on highly dehydroxylated silica were synthesized from TaMe5 (Me = methyl) and dimeric

  12. Heterolytic cleavage of ammonia N-H bond by bifunctional activation in silica-grafted single site Ta(V) imido amido surface complex. Importance of the outer sphere NH3 assistance

    KAUST Repository

    Gouré , Eric; Avenier, Priscilla; Solá ns, Xavier Luis; Veyre, Laurent; Baudouin, Anne Christine; Kaya, Yasemin; Taoufik, Mostafa; Basset, Jean-Marie; Eisenstein, Odile; Quadrelli, Elsje Alessandra

    2011-01-01

    and imido groups have accessible energy barriers. The energy barrier for the ammonia N-H activation by the Ta-amido group is energetically preferred relative to the Ta-imido group. The importance of excess NH3 for getting full isotope scrambling

  13. Investigating the widely held belief that men and women with learning disabilities receive poor quality healthcare when admitted to hospital: a single-site study of 30-day readmission rates.

    Science.gov (United States)

    Kelly, C L; Thomson, K; Wagner, A P; Waters, J P; Thompson, A; Jones, S; Holland, A J; Redley, M

    2015-09-01

    This study aims to use 30-day readmission rates to investigate the presumption that men and women with learning disabilities (LDs, known internationally as intellectual disabilities) receive poorer quality hospital care than their non-disabled peers. A 12-month retrospective audit was conducted using Hospital Episode Statistics (HES) at a single acute hospital in the East of England. This identified all in-patient admissions; admissions where the person concerned was recognised as having a LD; and all emergency readmissions within 30 days of discharge. Additionally, the healthcare records of all patients identified as having a LD and readmitted within 30 days as a medical emergency were examined in order to determine whether or not these readmissions were potentially preventable. Over the study period, a total of 66 870 adults were admitted as in-patients, among whom 7408 were readmitted as medical emergencies within 30 days of discharge: a readmission rate of 11%. Of these 66 870 patients, 256 were identified as having a LD, with 32 of them experiencing at least one emergency readmission within 30 days: a readmission rate of 13%. When examined, the healthcare records pertaining to these 32 patients who had a total of 39 unique 30-day readmissions revealed that 69% (n = 26) of these readmissions were potentially preventable. Although overall readmission rates were similar for patients with LDs and those from the general population, patients with LDs had a much higher rate of potentially preventable readmissions when compared to a general population estimate from van Walraven et al. This suggests that there is still work to be done to ensure that this patient population receives hospital care that is both safe and of high quality. © 2015 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

  14. Impact of novel techniques on minimally invasive adrenal surgery: trends and outcomes from a contemporary international large series in urology.

    Science.gov (United States)

    Pavan, Nicola; Autorino, Riccardo; Lee, Hak; Porpiglia, Francesco; Sun, Yinghao; Greco, Francesco; Jeff Chueh, S; Han, Deok Hyun; Cindolo, Luca; Ferro, Matteo; Chen, Xiang; Branco, Anibal; Fornara, Paolo; Liao, Chun-Hou; Miyajima, Akira; Kyriazis, Iason; Puglisi, Marco; Fiori, Cristian; Yang, Bo; Fei, Guo; Altieri, Vincenzo; Jeong, Byong Chang; Berardinelli, Francesco; Schips, Luigi; De Cobelli, Ottavio; Chen, Zhi; Haber, Georges-Pascal; He, Yao; Oya, Mototsugu; Liatsikos, Evangelos; Brandao, Luis; Challacombe, Benjamin; Kaouk, Jihad; Darweesh, Ithaar

    2016-10-01

    To evaluate contemporary international trends in the implementation of minimally invasive adrenalectomy and to assess contemporary outcomes of different minimally invasive techniques performed at urologic centers worldwide. A retrospective multinational multicenter study of patients who underwent minimally invasive adrenalectomy from 2008 to 2013 at 14 urology institutions worldwide was included in the analysis. Cases were categorized based on the minimally invasive adrenalectomy technique: conventional laparoscopy (CL), robot-assisted laparoscopy (RAL), laparoendoscopic single-site surgery (LESS), and mini-laparoscopy (ML). The rates of the four treatment modalities were determined according to the year of surgery, and a regression analysis was performed for trends in all surgical modalities. Overall, a total of 737 adrenalectomies were performed across participating institutions and included in this analysis: 337 CL (46 % of cases), 57 ML (8 %), 263 LESS (36 %), and 80 RA (11 %). Overall, 204 (28 %) operations were performed with a retroperitoneal approach. The overall number of adrenalectomies increased from 2008 to 2013 (p = 0.05). A transperitoneal approach was preferred in all but the ML group (p Asia and South America reported the highest rate in LESS procedures, and RAL was adopted to larger extent in the USA. LESS had the fastest increase in utilization at 6 %/year. The rate of RAL procedures increased at slower rates (2.2 %/year), similar to ML (1.7 %/year). Limitations of this study are the retrospective design and the lack of a cost analysis. Several minimally invasive surgical techniques for the management of adrenal masses are successfully implemented in urology institutions worldwide. CL and LESS seem to represent the most commonly adopted techniques, whereas ML and RAL are growing at a slower rate. All the MIS techniques can be safely and effectively performed for a variety of adrenal disease.

  15. Virtually transparent epidermal imagery (VTEI): on new approaches to in vivo wireless high-definition video and image processing.

    Science.gov (United States)

    Anderson, Adam L; Lin, Bingxiong; Sun, Yu

    2013-12-01

    This work first overviews a novel design, and prototype implementation, of a virtually transparent epidermal imagery (VTEI) system for laparo-endoscopic single-site (LESS) surgery. The system uses a network of multiple, micro-cameras and multiview mosaicking to obtain a panoramic view of the surgery area. The prototype VTEI system also projects the generated panoramic view on the abdomen area to create a transparent display effect that mimics equivalent, but higher risk, open-cavity surgeries. The specific research focus of this paper is on two important aspects of a VTEI system: 1) in vivo wireless high-definition (HD) video transmission and 2) multi-image processing-both of which play key roles in next-generation systems. For transmission and reception, this paper proposes a theoretical wireless communication scheme for high-definition video in situations that require extremely small-footprint image sensors and in zero-latency applications. In such situations the typical optimized metrics in communication schemes, such as power and data rate, are far less important than latency and hardware footprint that absolutely preclude their use if not satisfied. This work proposes the use of a novel Frequency-Modulated Voltage-Division Multiplexing (FM-VDM) scheme where sensor data is kept analog and transmitted via "voltage-multiplexed" signals that are also frequency-modulated. Once images are received, a novel Homographic Image Mosaicking and Morphing (HIMM) algorithm is proposed to stitch images from respective cameras, that also compensates for irregular surfaces in real-time, into a single cohesive view of the surgical area. In VTEI, this view is then visible to the surgeon directly on the patient to give an "open cavity" feel to laparoscopic procedures.

  16. [Current status and changes of metabolic and bariatric surgery in China].

    Science.gov (United States)

    Liu, Jingang

    2017-04-25

    Through continuous development, metabolic and bariatric surgery (MBS) has become widely recognized in academic and medical circles. In China, the volume of MBS operations has increased year by year. Therapeutic goals of MBS have evolved from treating obesity to treating Type 2 diabetes mellitus, and further to treating a series of obesity-associated metabolic diseases (including conditions in the endocrine system, circulatory system, respiratory system, reproductive system, and etc). Surgical approach of MBS has also been evolving continuously. Currently the common surgical procedures include laparoscopic Roux-en-Y gastric bypass (LRYGB), laparoscopic sleeve gastrectomy (LSG), laparoscopic adjustable gastric banding (LAGB) and bilio-pancreatic diversion with duodenal switch (BPD-DS). All surgical procedures have pros and cons, and the choice of surgical procedures should be based on the conditions of patients, the surgeon's technical ability, and benefits and operative risks. With the development of MBS, the proportions of different surgical procedures also changed in China. In recent five years, the proportion of AGB has decreased continuously and LAGB is no longer a common procedure. The proportion of LSG has increased rapidly, rising from 9% in 2010 to 55% in 2015. The proportion of RYGB has increased from 57% to 64% between 2010 and 2013, and remained at 45% afterwards. Since 2010, most MBS operations are laparoscopic surgery. 3D Laparoscopic surgery, laparoendoscopic single-site surgery and da Vinci Robotic Surgery have also been introduced in MBS. This review discusses the status quo and changes of MBS in china, as well as the new technology in MBS, aiming to strengthen the information and comprehension of MBS in china.

  17. Distal pancreatectomy and splenectomy: a robotic or LESS approach.

    Science.gov (United States)

    Ryan, Carrie E; Ross, Sharona B; Sukharamwala, Prashant B; Sadowitz, Benjamin D; Wood, Thomas W; Rosemurgy, Alexander S

    2015-01-01

    The role and application of robotic surgery are debated, particularly given the expansion of laparoscopy, especially laparoendoscopic single-site (LESS) surgery. This cohort study was undertaken to delineate differences in outcomes between LESS and robotic distal pancreatectomy and splenectomy. With Institutional Review Board approval, patients undergoing LESS or robotic distal pancreatectomy and splenectomy from September 1, 2012, through December 31, 2014, were prospectively observed, and data were collected. The results are expressed as the median, with the mean ± SD. Thirty-four patients underwent a minimally invasive distal pancreatectomy and splenectomy: 18 with robotic and 16 with LESS surgery. The patients were similar in sex, age, and body mass index. Conversions to open surgery and estimated blood loss were similar. There were two intraoperative complications in the group that underwent the robotic approach. Time spent in the operating room was significantly longer with the robot (297 vs 254 minutes, P = .03), although operative duration (i.e., incision to closure) was not longer (225 vs 190 minutes; P = .15). Of the operations studied, 79% were undertaken for neoplastic processes. Tumor size was 3.5 cm for both approaches; R0 resections were achieved in all patients. Length of stay was similar in the two study groups (5 vs 4 days). There was one 30-day readmission after robotic surgery. Patient outcomes are similar with LESS or robotic distal pancreatectomy and splenectomy. Robotic operations require more time in the operating room. Both are safe and efficacious minimally invasive operations that follow similar oncologic principles for similar tumors, and both should be in the surgeon's armamentarium for distal pancreatectomy and splenectomy.

  18. The Effect of Product Safety Courses on the Adoption and Outcomes of LESS Surgery.

    Science.gov (United States)

    Toomey, Paul G; Ross, Sharona B; Choung, Edward; Donn, Natalie; Vice, Michelle; Luberice, Kenneth; Albrink, Michael; Rosemurgy, Alexander S

    2015-01-01

    As technology in surgery evolves, the medical instrument industry is inevitability involved in promoting the use and appropriate (ie, effective and safe) application of its products. This study was undertaken to evaluate industry-supported product safety courses in laparoendoscopic single-site (LESS) surgery, by using the metrics of surgeons' adoption of the technique, safety of the procedure, and surgeons' perception of the surgery. LESS surgery courses that involved didactic lectures, operative videos, operation observation, collaborative learning, and simulation, were attended by 226 surgeons. With Florida Hospital Tampa Institutional Review Board approval, the surgeons were queried before and immediately after the course, to assess their attitudes toward LESS surgery. Then, well after the course, the surgeons were contacted, repeatedly if necessary, to complete questionnaires. Before the course, 82% of the surgeons undertook more than 10 laparoscopic operations per month. Immediately after the course, 86% were confident that they were prepared to perform LESS surgery. Months after the course, 77% of the respondents had adopted LESS surgery, primarily cholecystectomy; 59% had added 1 or more trocars in 0-20% of their procedures; and 73% held the opinion that operating room observation was the most helpful learning experience. Complications with LESS surgery were noted 12% of the time. Advantages of the technique were better cosmesis (58%) and patient satisfaction (38%). Disadvantages included risk of complications (37%) and higher technical demand (25%). Seventy-eight percent viewed LESS surgery as an advancement in surgical technique. In multifaceted product safety courses, operating room observation is thought to provide the most helpful instruction for those wanting to undertake LESS surgery. The procedure has been safely adopted by surgeons who frequently perform laparoscopies. The tradeoff is in performing a more difficult technique to obtain better

  19. The Effect of Product Safety Courses on the Adoption and Outcomes of LESS Surgery

    Science.gov (United States)

    Toomey, Paul G.; Ross, Sharona B.; Choung, Edward; Donn, Natalie; Vice, Michelle; Luberice, Kenneth; Albrink, Michael

    2015-01-01

    Background and Objectives: As technology in surgery evolves, the medical instrument industry is inevitability involved in promoting the use and appropriate (ie, effective and safe) application of its products. This study was undertaken to evaluate industry-supported product safety courses in laparoendoscopic single-site (LESS) surgery, by using the metrics of surgeons' adoption of the technique, safety of the procedure, and surgeons' perception of the surgery. Methods: LESS surgery courses that involved didactic lectures, operative videos, operation observation, collaborative learning, and simulation, were attended by 226 surgeons. With Florida Hospital Tampa Institutional Review Board approval, the surgeons were queried before and immediately after the course, to assess their attitudes toward LESS surgery. Then, well after the course, the surgeons were contacted, repeatedly if necessary, to complete questionnaires. Results: Before the course, 82% of the surgeons undertook more than 10 laparoscopic operations per month. Immediately after the course, 86% were confident that they were prepared to perform LESS surgery. Months after the course, 77% of the respondents had adopted LESS surgery, primarily cholecystectomy; 59% had added 1 or more trocars in 0–20% of their procedures; and 73% held the opinion that operating room observation was the most helpful learning experience. Complications with LESS surgery were noted 12% of the time. Advantages of the technique were better cosmesis (58%) and patient satisfaction (38%). Disadvantages included risk of complications (37%) and higher technical demand (25%). Seventy-eight percent viewed LESS surgery as an advancement in surgical technique. Conclusion: In multifaceted product safety courses, operating room observation is thought to provide the most helpful instruction for those wanting to undertake LESS surgery. The procedure has been safely adopted by surgeons who frequently perform laparoscopies. The tradeoff is in

  20. New trends in minimally invasive urological surgery: what is beyond the robot?

    Science.gov (United States)

    Micali, Salvatore; Pini, Giovannalberto; Teber, Dogu; Sighinolfi, Maria Chiara; De Stefani, Stefano; Bianchi, Giampaolo; Rassweiler, Jens

    2013-06-01

    To review the minimal-invasive development of surgical technique in urology focusing on nomenclature, history and outcomes of Laparo-Endoscopic Single-site Surgery (LESS), Natural Orifice Translumenal Endoscopic Surgery (NOTES) and Computer-Assisted Surgery (CAS). A comprehensive literature search was conducted in order to find article related to LESS, NOTES and CAS in urology. The most relevant papers over the last 10 years were selected in base to the experience from the panel of experts, journal, authorship and/or content. Seven hundred and fifty manuscripts were found. Papers on LESS describe feasibility/safety in most of the procedures with a clinical experience of more than 300 cases and five compared results to standard laparoscopy without showing significant differences. NOTES accesses have been proved their feasibility/safety in experimental study. In human, the only procedures performed are on kidney and through a hybrid-Transvaginal route. New robots overcome the main drawbacks of the DaVinci® platform. The use of CAS is increasing its popularity in urology. LESS has been applied in clinical practice, but only ongoing technical and instrumental refinement will define its future role and overall benefit. The transition to a clinical application of NOTES seems at present only possible with multiple NOTES access and transvaginal access. Robot and Soft Tissue Navigation appear to be important to improve surgical skills. We are already witness to the advantages offered by the former even if costs need to be redefined based on pending long-term results. The latter will probably upgrade the quality of surgery in a near future.

  1. Minimally Invasive Pyeloplasty in Horseshoe Kidneys with Ureteropelvic Junction obstruction: A case series

    Directory of Open Access Journals (Sweden)

    Stephen Faddegon

    2013-04-01

    Full Text Available Background and Purpose Horseshoe kidney is an uncommon renal anomaly often associated with ureteropelvic junction (UPJ obstruction. Advanced minimally invasive surgical (MIS reconstructive techniques including laparoscopic and robotic surgery are now being utilized in this population. However, fewer than 30 cases of MIS UPJ reconstruction in horseshoe kidneys have been reported. We herein report our experience with these techniques in the largest series to date. Materials and Methods We performed a retrospective chart review of nine patients with UPJ obstruction in horseshoe kidneys who underwent MIS repair at our institution between March 2000 and January 2012. Four underwent laparoscopic, two robotic, and one laparoendoscopic single-site (LESS dismembered pyeloplasty. An additional two pediatric patients underwent robotic Hellstrom repair. Perioperative outcomes and treatment success were evaluated. Results Median patient age was 18 years (range 2.5-62 years. Median operative time was 136 minutes (range 109-230 min. and there were no perioperative complications. After a median follow-up of 11 months, clinical (symptomatic success was 100%, while radiographic success based on MAG-3 renogram was 78%. The two failures were defined by prolonged t1/2 drainage, but neither patient has required salvage therapy as they remain asymptomatic with stable differential renal function. Conclusions MIS repair of UPJ obstruction in horseshoe kidneys is feasible and safe. Although excellent short-term clinical success is achieved, radiographic success may be lower than MIS pyeloplasty in heterotopic kidneys, possibly due to inherent differences in anatomy. Larger studies are needed to evaluate MIS pyeloplasty in this population.

  2. Development of urologic laparoscopy in Germany, Austria, and Switzerland: a survey among urologists.

    Science.gov (United States)

    Imkamp, Florian; Herrmann, Thomas R W; Stolzenburg, Jens U; Rassweiler, Jens; Sulser, Tullio; Zimmermann, Uwe; Dziuba, Sebastian; Kuczyk, Markus A; Burchardt, Martin

    2014-12-01

    Laparoscopy introduction has dramatically changed urology. Novel techniques, such as laparoendoscopic single-site surgery (LESS) and natural orifice translumenal endoscopic surgery (NOTES), might also have substantial influence. This 2012 survey evaluated present laparoscopy use, its appraisal among urologic surgeons, laparoscopy training, and use of new techniques. Results were compared to the previous surveys, demonstrating the 10-year development of laparoscopy. A detailed questionnaire regarding demographic data, laparoscopy use, attitudes concerning laparoscopy, and novel techniques was send to 424 departments in Germany, Austria, and Switzerland. Procedures performed in 25 indications were quantitatively evaluated. The response rate was 63 % (269). Eighty-six percent of the respondents reported performing laparoscopy, compared to 54 % in 2002. Only 16 % expected economic advantages with laparoscopy, whereas 67 % expected shorter hospitalization. Seventy percent of responders anticipated comparable functional and oncological results between laparoscopic procedures and open surgery. Slow learning curves (81 %) and insufficient training facilities (32 %) were reported to impair laparoscopic surgery. On average, laparoscopic and non-laparoscopic surgical teams consisted of 2.5 and 3.5 members, respectively. LESS procedures were performed at 15 % of institutions. Twenty-two percent of respondents considered NOTES techniques valuable for future urology. Few indications (laparoscopic prostatectomies or nephrectomies) were performed frequently in specialized centers, and the rapidly increasing procedure numbers observed between 2002 and 2007 had dropped to a mild accretion. The results demonstrate broad acceptance of laparoscopy in German urologic surgery, depict the need for structured training facilities, and indicate limited impact of novel techniques (LESS and NOTES). The survey demonstrates the 10-year development of urologic laparoscopy and the broad acceptance

  3. Maximizing coupling strength of magnetically anchored surgical instruments: how thick can we go?

    Science.gov (United States)

    Best, Sara L; Bergs, Richard; Gedeon, Makram; Paramo, Juan; Fernandez, Raul; Cadeddu, Jeffrey A; Scott, Daniel J

    2011-01-01

    The Magnetic Anchoring and Guidance System (MAGS) includes an external magnet that controls intra-abdominal surgical instruments via magnetic attraction forces. We have performed NOTES (Natural Orifice Transluminal Endoscopic Surgery) and LESS (Laparoendoscopic Single Site) procedures using MAGS instruments in porcine models with up to 2.5-cm-thick abdominal walls, but this distance may not be sufficient in some humans. The purpose of this study was to determine the maximal abdominal wall thickness for which the current MAGS platform is suitable. Successive iterations of prototype instruments were developed; those evaluated in this study include external (134-583 g, 38-61 mm diameter) and internal (8-39 g, 10-22 mm diameter) components using various grades, diameters, thicknesses, and stacking/shielding/focusing configurations of permanent Neodymium-iron-boron (NdFeB) magnets. Nine configurations were tested for coupling strength across distances of 0.1-10 cm. The force-distance tests across an air medium were conducted at 0.5-mm increments using a robotic arm fitted with a force sensor. A minimum theoretical instrument drop-off (decoupling) threshold was defined as the separation distance at which force decreased below the weight of the heaviest internal component (39 g). Magnetic attraction forces decreased exponentially over distance. For the nine configurations tested, the average forces were 3,334 ± 1,239 gf at 0.1 cm, 158 ± 98 gf at 2.5 cm, and 8.7 ± 12 gf at 5 cm; the drop-off threshold was 3.64 ± 0.8 cm. The larger stacking configurations and magnets yielded up to a 592% increase in attraction force at 2.5 cm and extended the drop-off threshold distance by up to 107% over single-stack anchors. For the strongest configuration, coupling force ranged from 5,337 gf at 0.1 cm to 0 gf at 6.95 cm and yielded a drop-off threshold distance of 4.78 cm. This study suggests that the strongest configuration of currently available MAGS instruments is suitable for

  4. From single-site tantalum complexes to nanoparticles of Ta x N y and TaO x N y supported on silica: elucidation of synthesis chemistry by dynamic nuclear polarization surface enhanced NMR spectroscopy and X-ray absorption spectroscopy.

    Science.gov (United States)

    Mohandas, Janet C; Abou-Hamad, Edy; Callens, Emmanuel; Samantaray, Manoja K; Gajan, David; Gurinov, Andrei; Ma, Tao; Ould-Chikh, Samy; Hoffman, Adam S; Gates, Bruce C; Basset, Jean-Marie

    2017-08-01

    Air-stable catalysts consisting of tantalum nitride nanoparticles represented as a mixture of Ta x N y and TaO x N y with diameters in the range of 0.5 to 3 nm supported on highly dehydroxylated silica were synthesized from TaMe 5 (Me = methyl) and dimeric Ta 2 (OMe) 10 with guidance by the principles of surface organometallic chemistry (SOMC). Characterization of the supported precursors and the supported nanoparticles formed from them was carried out by IR, NMR, UV-Vis, extended X-ray absorption fine structure, and X-ray photoelectron spectroscopies complemented with XRD and high-resolution TEM, with dynamic nuclear polarization surface enhanced NMR spectroscopy being especially helpful by providing enhanced intensities of the signals of 1 H, 13 C, 29 Si, and 15 N at their natural abundances. The characterization data provide details of the synthesis chemistry, including evidence of (a) O 2 insertion into Ta-CH 3 species on the support and (b) a binuclear to mononuclear transformation of species formed from Ta 2 (OMe) 10 on the support. A catalytic test reaction, cyclooctene epoxidation, was used to probe the supported nanoparticles, with 30% H 2 O 2 serving as the oxidant. The catalysts gave selectivities up to 98% for the epoxide at conversions as high as 99% with a 3.4 wt% loading of Ta present as Ta x N y /TaO x N y .

  5. Single-incision total laparoscopic hysterectomy

    Directory of Open Access Journals (Sweden)

    Sinha Rakesh

    2011-01-01

    Full Text Available Single-incision laparoscopic surgery is an alternative to conventional multiport laparoscopy. Single-access laparoscopy using a transumbilical port affords maximum cosmetic benefits because the surgical incision is hidden in the umbilicus. The advantages of single-access laparoscopic surgery may include less bleeding, infection, and hernia formation and better cosmetic outcome and less pain. The disadvantages and limitations include longer surgery time, difficulty in learning the technique, and the need for specialized instruments. Ongoing refinement of the surgical technique and instrumentation is likely to expand its role in gynecologic surgery in the future. We perform single-incision total laparoscopic hysterectomy using three ports in the single transumbilical incision.

  6. Single incision laparoscopic pancreas resection for pancreatic metastasis of renal cell carcinoma.

    Science.gov (United States)

    Barbaros, Umut; Sümer, Aziz; Demirel, Tugrul; Karakullukçu, Nazlı; Batman, Burçin; Içscan, Yalın; Sarıçam, Gülay; Serin, Kürçsat; Loh, Wei-Liang; Dinççağ, Ahmet; Mercan, Selçuk

    2010-01-01

    Transumbilical single incision laparoscopic surgery (SILS) offers excellent cosmetic results and may be associated with decreased postoperative pain, reduced need for analgesia, and thus accelerated recovery. Herein, we report the first transumbilical single incision laparoscopic pancreatectomy case in a patient who had renal cell cancer metastasis on her pancreatic corpus and tail. A 59-year-old female who had metastatic lesions on her pancreas underwent laparoscopic subtotal pancreatectomy through a 2-cm umbilical incision. Single incision pancreatectomy was performed with a special port (SILS port) and articulated equipment. The procedure lasted 330 minutes. Estimated blood loss was 100mL. No perioperative complications occurred. The patient was discharged on the seventh postoperative day with a low-volume (20mL/day) pancreatic fistula that ceased spontaneously. Pathology result of the specimen was renal cell cancer metastases. This is the first reported SILS pancreatectomy case, demonstrating that even advanced surgical procedures can be performed using the SILS technique in well-experienced centers. Transumbilical single incision laparoscopic pancreatectomy is feasible and can be performed safely in experienced centers. SILS may improve cosmetic results and allow accelerated recovery for patients even with malignancy requiring advanced laparoscopic interventions.

  7. Mimicking physiological O2 tension in the female reproductive tract improves Assisted Reproduction outcomes in pig.

    Science.gov (United States)

    García-Martínez, S; Sánchez-Hurtado, M A; Gutiérrez, H; Sánchez-Margallo, F M; Romar, R; Latorre, R; Coy, P; López-Albors, O

    2018-02-27

    Is O2 tension in the pig oviduct and uterus affected by the estrous cycle stage and the animal's age, and can the outcome of in vitro embryo development be improved by mimicking these physiological values? O2 tension within the pig reproductive organs is affected by the animal's age, and values close to those measured in vivo have a positive impact on embryo development and quality when used during IVF and embryo culture (EC). To obtain a healthy embryo in vitro, it is necessary to adopt a culture microenvironment that approximates physiological conditions. Despite advances in surgical procedures and sensitive probes that allow accurate assessment of in vivo O2 tension, few such studies have been conducted recently in mammals. In addition, no reference values of physiological O2 tension in the reproductive tract exist for large animal models such as pig, and the effect of O2 tension on ART outcomes is unknown. This study was conducted in pigs. We measured oviductal and uterine O2 tension (n = 29 and 13 respectively) and then examined how the use of the physiological values in pig IVF and EC affected pig ART output (n = 1447 oocytes). The oviductal and uterine O2 tension at the different stages of the estrous cycle was monitored using a laparo-endoscopic single-site surgery (LESS) assisted approach along with a flexible and thin miniaturized luminescent probe. Two groups of pigs, Large-white x Landrace breed, were used: for the first group, 16 pre-pubertal gilts (5 months old and 95 kg) were induced to ovulate with equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG); in the second group 13 mature sows (24-48 months and 185 kg) were used. IVF and EC were performed at two different O2 tensions: Atmospheric O2 (20%) and the mean in vivo value measured (7%). At 18-20 hours post-insemination (hpi), a small sample of presumptive zygotes were fixed, stained, and examined under epifluorescence microscopy to assess the fertilization rates. At

  8. Prospective randomized clinical trial comparing laparoscopic cholecystectomy and hybrid natural orifice transluminal endoscopic surgery (NOTES) (NCT00835250).

    Science.gov (United States)

    Noguera, José F; Cuadrado, Angel; Dolz, Carlos; Olea, José M; García, Juan C

    2012-12-01

    Natural orifice transluminal endoscopic surgery (NOTES) is a technique still in experimental development whose safety and effectiveness call for assessment through clinical trials. In this paper we present a three-arm, noninferiority, prospective randomized clinical trial of 1 year duration comparing the vaginal and transumbilical approaches for transluminal endoscopic surgery with the conventional laparoscopic approach for elective cholecystectomy. Sixty female patients between the ages of 18 and 65 years who were eligible for elective cholecystectomy were randomized in a ratio of 1:1:1 to receive hybrid transvaginal NOTES (TV group), hybrid transumbilical NOTES (TU group) or conventional laparoscopy (CL group). The main study variable was parietal complications (wound infection, bleeding, and eventration). The analysis was by intention to treat, and losses were not replaced. Cholecystectomy was successfully performed on 94% of the patients. One patient in the TU group was reconverted to CL owing to difficulty in maneuvering the endoscope. After a minimum follow-up period of 1 year, no differences were noted in the rate of parietal complications. Postoperative pain, length of hospital stay, and time off from work were similar in the three groups. No patient developed dyspareunia. Surgical time was longer among cases in which a flexible endoscope was used (CL, 47.04 min; TV, 64.85 min; TU, 59.80 min). NOTES approaches using the flexible endoscope are not inferior in safety or effectiveness to conventional laparoscopy. The transumbilical approach with flexible endoscope is as effective and safe as the transvaginal approach and is a promising, single-incision approach.

  9. [Giant paraovarian cyst in childhood - Case report].

    Science.gov (United States)

    Torres, Janina P; Íñiguez, Rodrigo D

    2015-01-01

    Paraovarian cysts are very uncommon in children To present a case of giant paraovarian cyst case in a child and its management using a modified laparoscopic-assisted technique A 13-year-old patient with a 15 day-history of intermittent abdominal pain, located in the left hemiabdomen and associated with progressive increase in abdominal volume. Diagnostic imaging was inconclusive, describing a giant cystic formation that filled up the abdomen, but without specifying its origin. Laboratory tests and tumor markers were within normal range. Video-assisted transumbilical cystectomy, a modified laparoscopic procedure with diagnostic and therapeutic intent, was performed with a successful outcome. The histological study reported giant paraovarian cyst. Cytology results were negative for tumor cells. The patient remained asymptomatic during the postoperative follow-up. The video-assisted transumbilical cystectomy is a safe procedure and an excellent diagnostic and therapeutic alternative for the treatment of giant paraovarian cysts. Copyright © 2015. Publicado por Elsevier España, S.L.U.

  10. Single-incision laparoscopic cholecystectomy with needle graspers.

    Science.gov (United States)

    Sumiyoshi, Kinjiro; Sato, Norihiro; Akagawa, Shin; Hirano, Tatsuya; Koikawa, Kazuhiro; Horioka, Kohei; Ozono, Keigo; Fujiwara, Kenji; Tanaka, Masao; Sada, Masayuki

    2012-01-01

    Single-incision laparoscopic cholecystectomy (SILC) is a promising alternative to standard multi-incision laparoscopic cholecystectomy (LC). However, generalization of SILC is still hampered by technical difficulties mainly associated with the lack of trocars used for retraction of the gallbladder. We therefore developed a modified method of SILC with the use of needle graspers (SILC-N) for optimal retraction and exposure. In addition to two trocars inserted through a single transumbilical incision, two needle ports were placed on the right subcostal and lateral abdominal wall, through which needle graspers were used for retraction of the gallbladder. Since December, 2009, 12 patients with symptomatic cholelithiasis were treated by SILC-N. SILC-N was successfully performed in all but one patient requiring a conversion to the 4-port LC with a mean operative time of 71.5 (48-107) minutes. None of the patients experienced intraoperative or postoperative complications. The transumbilical incision and pinholes for needle graspers were almost invisible on discharge. Our preliminary results suggest that SILC-N is a simple, safe and feasible technique of cholecystectomy offering similar postoperative recovery and better cosmetic outcome as compared to conventional LC.

  11. Prolapse of inverted ileal loops through a patent vitellointestinal duct

    Science.gov (United States)

    Pathak, Ashish; Agarwal, Nitin; Singh, Poonam; Dhaneria, Mamta

    2015-01-01

    We report a case of a prolapsed patent vitellointestinal duct (PVID) in a 2-month-old girl child who presented with sudden increase in size of a polypoidal lesion into a large, ‘Y’-shaped reddish, prolapsing lesion, discharging gaseous and faecal matter at her umbilicus. The lesion was diagnosed as a prolapse of inverted ileal loops through the PVID. The child had no associated congenital anomalies. A transumbilical exploration was performed, followed by wedge resection and anastomosis. The child tolerated the procedure well and the postoperative course was uneventful. If the omphalomesenteric duct fails to obliterate a range of congenital defects related to the umbilicus, it can become clinically apparent. Meckel's diverticulum is the commonest of these defects but is most often asymptomatic. PVID is the most common symptomatic anomaly of the patent omphalomesenteric duct and requires prompt surgical correction to avoid complications. PMID:26494719

  12. Microlaparoscopic technique for partial salpingectomy using bipolar electrocoagulation.

    Science.gov (United States)

    Siegle, J C; Cartmell, L W; Rayburn, W F

    2001-07-01

    To describe a technique of performing a partial salpingectomy using a small-diameter (2-mm) laparoscope and bipolar electrocoagulation. Sixty consecutive women desiring permanent sterilization underwent laparoscopic partial salpingectomy using a 2-mm transumbilical laparoscope and secondary midline sites suprapubically and midway above the pubis. A midportion of the tube was coagulated using Kleppinger forceps, transected with scissors and removed using grasping forceps. Additional time to remove both coagulated tubal segments averaged 4 minutes (range, 3-10). Each segment (mean, 1.5 cm; range, 0.9-2.4 cm) was confirmed in the operating room, then histologically. The transected tubal edges were separated with no thermal injury to nearby structures and with no mesosalpingeal hemorrhage. No cases required conversion from microlaparoscopy to a traditional method, and recovery time was not prolonged. The puncture sites healed well without sutures. Successful removal of electrocoagulated tubal segments with histologic confirmation was undertaken microlaparoscopically, with minimal additional operative time.

  13. Construction of a specification from its singleton part

    NARCIS (Netherlands)

    Fernández, R.; Maillard, G.

    2006-01-01

    We state a construction theorem for specications starting from single-site conditional probabilities (singleton part). We consider general single-site spaces and kernels that are absolutely continuous with respect to a chosen product mea- sure (free measure). Under a natural order-consistency

  14. International guidelines for groin hernia management

    DEFF Research Database (Denmark)

    Jørgensen, Lars Nannestad; Bisgaard, Thue

    2018-01-01

    a complete search by The Dutch Cochrane database) to January 1, 2015 and to July 1, 2015 for level 1 publications. The articles were scored by teams of two or three according to Oxford, SIGN and Grade methodologies. During five 2-day meetings, results were discussed with the working group members leading......-risk environments is not recommended in open surgery. In laparo-endoscopic repair it is never recommended. Local anesthesia in open repair has many advantages, and its use is recommended provided the surgeon is experienced in this technique. General anesthesia is suggested over regional in patients aged 65...... of clinically significant chronic pain is in the 10-12% range, decreasing over time. Debilitating chronic pain affecting normal daily activities or work ranges from 0.5 to 6%. Chronic postoperative inguinal pain (CPIP) is defined as bothersome moderate pain impacting daily activities lasting at least 3 months...

  15. Temperature Dependence of the Stability of Ion Pair Interactions ...

    Indian Academy of Sciences (India)

    The occurrence of bridging water molecules between the ions ensures that the ions are not ... The structural features that render this thermostability ..... dehydrogenase single site mutant T198I from Thermus thermophilus with PDB ID 1BDM.

  16. TEK twisted gradient flow running coupling

    CERN Document Server

    Pérez, Margarita García; Keegan, Liam; Okawa, Masanori

    2014-01-01

    We measure the running of the twisted gradient flow coupling in the Twisted Eguchi-Kawai (TEK) model, the SU(N) gauge theory on a single site lattice with twisted boundary conditions in the large N limit.

  17. The Evolution of the Appendectomy: From Open to Laparoscopic to Single Incision

    Directory of Open Access Journals (Sweden)

    Noah J. Switzer

    2012-01-01

    Full Text Available Beginning with its initial description by Fitz in the 19th century, acute appendicitis has been a significant long-standing medical challenge; today it remains the most common gastrointestinal emergency in adults. Already in 1894, McBurney advocated for the surgical removal of the inflamed appendix and is credited with the initial description of an Open Appendectomy (OA. With the introduction of minimally invasive surgery, this classic approach evolved into a procedure with multiple, smaller incisions; a technique termed Laparoscopic Appendectomy (LA. There is much literature describing the advantages of this newer approach. To name a few, patients have significantly less wound infections, reduced pain, and a reduction in ileus compared with the OA. In the past few years, Single Incision Laparoscopic Appendectomy (SILA has gained popularity as the next major evolutionary advancement in the removal of the appendix. Described as a pioneer in the era of “scarless surgery,” it involves only one transumbilical incision. Patients are postulated to have reduced post-operative complications such as infection, hernias, and hematomas, as well as a quicker recovery time and less post-operative pain scores, in comparison to its predecessors. In this review, we explore the advancement of the appendectomy from open to laparoscopic to single incision.

  18. Solo-Surgeon Single-Port Laparoscopic Anterior Resection for Sigmoid Colon Cancer: Comparative Study.

    Science.gov (United States)

    Choi, Byung Jo; Jeong, Won Jun; Kim, Say-June; Lee, Sang Chul

    2018-03-01

    To report our experience with solo-surgeon, single-port laparoscopic anterior resection (solo SPAR) for sigmoid colon cancer. Data from sigmoid colon cancer patients who underwent anterior resections (ARs) using the single-port, solo surgery technique (n = 31) or the conventional single-port laparoscopic technique (n = 45), between January 2011 and July 2016, were retrospectively analyzed. In the solo surgeries, making the transumbilical incision into the peritoneal cavity was facilitated through the use of a self-retaining retractor system. After establishing a single port through the umbilicus, an adjustable mechanical camera holder replaced the human scope assistant. Patient and tumor characteristics and operative, pathologic, and postoperative outcomes were compared. The operative times and estimated blood losses were similar for the patients in both treatment groups. In addition, most of the postoperative variables were comparable between the two groups, including postoperative complications and hospital stays. In the solo SPAR group, comparable lymph nodes were attained, and sufficient proximal and distal cut margins were obtained. The difference in the proximal cut margin significantly favored the solo SPAR, compared with the conventional AR group (P = .000). This study shows that solo SPAR, using a passive camera system, is safe and feasible for use in sigmoid colon cancer surgery, if performed by an experienced laparoscopic surgeon. In addition to reducing the need for a surgical assistant, the oncologic requirements, including adequate margins and sufficient lymph node harvesting, could be fulfilled. Further evaluations, including prospective randomized studies, are warranted.

  19. Single port Billroth I gastrectomy

    Directory of Open Access Journals (Sweden)

    Jeremy R Huddy

    2013-01-01

    Full Text Available Introduction: Experience has allowed increasingly complex procedures to be undertaken by single port surgery. We describe a technique for single port Billroth I gastrectomy with a hand-sewn intracorporeal anastomosis in the resection of a benign tumour diagnosed incidentally on a background of cholelithiasis. Materials and Methods: Single port Billroth I gastrectomy and cholecystectomy was performed using a transumbilical quadport. Flexible tipped camera and straight conventional instruments were used throughout the procedure. The stomach was mobilised including a limited lymph node dissection and resection margins in the proximal antrum and duodenum were divided with a flexible tipped laparoscopic stapler. The lesser curve was reconstructed and an intracorporal hand sewn two layer end-to-end anastomosis was performed using unidirectional barbed sutures. Intraoperative endoscopy confirmed the anastomosis to be patent without leak. Results: Enteral feed was started on the day of surgery, increasing to a full diet by day 6. Analgesic requirements were a patient-controlled analgesia morphine pump for 4 postoperative days and paracetamol for 6 days. There were no postoperative complications and the patient was discharged on the eighth day. Histology confirmed gastric submucosal lipoma. Discussion: As technology improves more complex procedures are possible by single port laparoscopic surgery. In this case, flexible tipped cameras and unidirectional barbed sutures have facilitated an intracorporal hand-sewn two layer end-to-end anastomosis. Experience will allow such techniques to become mainstream.

  20. One-trocar appendectomy.

    Science.gov (United States)

    Rispoli, G; Armellino, M F; Esposito, C

    2002-05-01

    Laparoscopic appendectomy is a feasible and a safe alternative to open appendectomy. Several laparoscopic procedures have been described that use one or more trocars. We report our experience with the treatment of acute appendicitis using a laparoscopy-assisted technique by means of only one transumbilical trocar. From February 1996 to February 1999 we performed 65 laparoscopic appendectomies. In the procedures, a 10-mm operative telescope was used, with a 450-mm atraumatic grasper introduced through the operative channel. After the intraabdominal laparoscopic dissection, the appendix was exteriorized through the umbilical trocar. The appendectomy was performed outside the abdomen as in the open procedure. The procedure was completed using only one trocar in 55 patients (84.6%). Regarding the other 10 cases (15.3%), in 5 we used more than one trocar and in 5 conversion to open surgery was needed. The average operating time in our series was 25 min and the median time to discharge was 2 days. There were six (11%) postoperative complications (three serous umbilical secretion and three umbilical hematomas). Our results suggest that this technique, which combines the advantages of both the open and the laparoscopic procedures, is a valid alternative for the treatment of acute appendicitis. However, this procedure cannot always be completed using only one trocar, as happened in 10 cases in our series.

  1. The transverse colon cancer with the reversed rotation of the midgut treated with single incision laparoscopic colectomy.

    Science.gov (United States)

    Hirano, Yasumitsu; Hattori, Masakazu; Fujita, Manami; Nishida, Youji; Douden, Kenji; Hashizume, Yasuo

    2013-06-01

    Reversed rotation of the midgut is a rare type of intestinal malrotation. Moreover, synchronous colon cancer has rarely been reported. Preliminary experience with single-incision laparoscopic colectomy (SILC) for colon cancer with reversed rotation of the midgut is reported. An 82-year-old woman was admitted because of a fecal occult blood. A colonoscopy revealed transverse colon cancer. An air-barium contrast enema showed the right-sided sigmoid colon and the left-sided cecum. A computed tomography revealed that the duodenum and the transverse colon were situated at the ventral side of the superior mesenteric artery, and a preoperative diagnosis of suspicion of reversed rotation of the midgut was made. First, a lap protector was inserted through a 4.0 cm transumbilical incision. Four 5 mm ports were placed in the lap protector. On the observation of laparoscopy, the cecum and the ascending colon were not fixed with the retroperitoneum and situated on the left, and the sigmoid colon was situated on the right. We successfully mobilized the transverse colon using a single-incision laparoscopic approach. Resection was achieved following extracorporealization, and the anastomosis was performed extracorporeally using staplers. The patient was discharged on the thirteenth postoperative day. Postoperative follow-up did not reveal any umbilical wound complications. SILC for colon cancer associated with malrotation of the midgut is feasible and a promising alternative method because of its less invasiveness and its adaptability to the malrotation without extending the skin incision.

  2. Single-Access Laparoscopic Surgery for Ileal Disease

    Directory of Open Access Journals (Sweden)

    Mohamed Moftah

    2012-01-01

    Full Text Available Aim. Single-access laparoscopic surgery (SALS can be effective for benign and malignant diseases of the ileum in both the elective and urgent setting. Methods. Ten consecutive, nonselected patients with ileal disease requiring surgery over a twelve month period were included. All had a preoperative abdominopelvic computerized tomogram. Peritoneal access was achieved via a single transumbilical incision and a “surgical glove port” utilized as our preferred access device. With the pneumoperitoneum established, the relevant ileal loop was located using standard rigid instruments. For ileal resection, anastomosis, or enterotomy, the site of pathology was delivered and addressed extracorporeally. Result. The median (range age of the patients was 42.5 (22–78 years, and the median body mass index was 22 (20.2–28 kg/m2. Procedures included tru-cut biopsy of an ileal mesenteric mass, loop ileostomy and ileotomy for impacted gallstone extraction as well as ileal (=3 and ileocaecal resection (=4. Mean (range incision length was 2.5 (2–5 cm. All convalescences were uncomplicated. Conclusions. These preliminary results show that SALS is an efficient and safe modality for the surgical management of ileal disease with all the advantages of minimal access surgery and without requiring a significant increase in theatre resource or cost or incurring extra patient morbidity.

  3. Single-port access laparoscopic hysterectomy: a new dimension of minimally invasive surgery.

    Science.gov (United States)

    Liliana, Mereu; Alessandro, Pontis; Giada, Carri; Luca, Mencaglia

    2011-01-01

    The fundamental idea is to have all of the laparoscopic working ports entering the abdominal wall through the same incision. Single-incision laparoscopic surgery is an alternative to conventional multiport laparoscopy. Single-access laparoscopy using a transumbilical port affords maximum cosmetic benefits because the surgical incision is hidden in the umbilicus and reduces morbidity of minimally invasive surgery. The advantages of single-access laparoscopic surgery may include less bleeding, infection, and hernia formation and better cosmetic outcome and less pain. The disadvantages and limitations include longer surgery time, difficulty in learning the technique, and the need for specialized instruments. This review summarizes the history of SPAL hysterectomy (single-port access laparoscopy), and emphasizes nomenclature, surgical technique, instrumentation, and perioperative outcomes. Specific gynecological applications of single-port hysterectomy to date are summarized. Using the PubMed database, the English-language literature was reviewed for the past 40 years. Keyword searches included scarless, scar free, single-port/trocar/incision, single-port access laparoscopic hysterectomy. Within the bibliography of selected references, additional sources were retrieved. The purpose of the present article was to review the development and current status of SPAL hysterectomy and highlight important advances associated with this innovative approach.

  4. Managing obstructive gastric volvulus: challenges and solutions

    Directory of Open Access Journals (Sweden)

    Rodriguez-Garcia HA

    2017-03-01

    Full Text Available Hector Alejandro Rodriguez-Garcia,1 Andrew S Wright,2–4 Robert B Yates1–3 1Department of Surgery, Center for Esophageal and Gastric Surgery, 2Center for Videoendoscopic Surgery, 3Hernia Center, 4Institute for Simulation and Interprofessional Studies, UWMC, University of Washington, Seattle, USA Abstract: Gastric volvulus is the abnormal torsion of the stomach along its short or long axis. Most patients who experience gastric volvulus present with mild or intermittent gastric obstructive symptoms. However, severe acute gastric volvulus can result in complete gastric outlet obstruction and ischemia. Consequently, acute gastric volvulus warrants immediate evaluation and management. The goals of management are to relieve the obstruction and prevent recurrent volvulus. Techniques to manage gastric volvulus depend on patient characteristics and the presence of gastric ischemia. In the absence of gastric ischemia, gastric volvulus can be managed with anterior abdominal wall gastropexy or paraesophageal hernia repair. If gastric ischemia is present, operative resection of the affected portion of the stomach is indicated. When operative management is indicated, many patients with gastric volvulus can be managed with minimally invasive (laparoscopic, endoscopic, or laparoendoscopic techniques. Keywords: gastric volvulus, paraesophageal hernia, hiatal hernia

  5. Validación de la histerectomía laparoscópica por un solo puerto quirúrgico como una nueva técnica en Cuba Validation of the laparoscopic hysterectomy through an only surgical approach as a new technique in Cuba

    Directory of Open Access Journals (Sweden)

    Javier Ernesto Barreras González

    2011-12-01

    Full Text Available Introducción: disminuir la agresión a la biología del paciente y minimizar el acceso al área quirúrgica, ha sido una preocupación y una ambición permanente del cirujano. La cirugía a través de orificios naturales implica ganar el acceso a la cavidad abdominal a través del estómago, colon, vagina, útero o vejiga; y elimina, de hecho, los puertos de entrada en la pared abdominal, lo cual la incluye en un nuevo paradigma quirúrgico: la cirugía sin huellas. En el año 2007 se propone una nueva técnica de cirugía endoscópica transumbilical, acorde con los principios técnicos de la cirugía a través de orificios naturales. Su uso en ginecología comienza desde la década de los años setenta cuando se realizaron ligaduras tubarias, y recientemente se han introducido innovadoras técnicas de un solo puerto en procedimientos más complejos. Objetivos: demostrar la factibilidad y seguridad de la histerectomía laparoscópica por un solo puerto quirúrgico mediante una nueva técnica. Métodos: estudio prospectivo de serie de casos. Se realizó la técnica de histerectomía totalmente laparoscópica mediante un solo puerto quirúrgico y con instrumentos diseñados para tal efecto. Resultados: se realizó esta técnica a 10 pacientes con diagnóstico de fibroma uterino. El tiempo quirúrgico fue de 115 minutos (75-160 y la media de sangrado de 75 mL (20-400, y no se observaron complicaciones intraoperatorias ni posoperatorias en los casos estudiados. Conclusiones: la histerectomía laparoscópica por un solo puerto es una técnica factible, segura y reproducible a otros servicios de cirugía de mínimo acceso del país.Introduction: to decrease the act of aggression to patient's biology and to minimize the access to surgical area has been a concern and also a permanent ambition of surgeon. Surgery thorough natural orifices involves to access to abdominal cavity through stomach, colon, vagina, uterus or bladder and in fact eliminates the

  6. Novel approach of single-port laparoscopic appendectomy as a solo surgery: A prospective cohort study.

    Science.gov (United States)

    Kim, Say-June; Choi, Byung-Jo; Lee, Sang Chul

    2015-09-01

    Recent advances in medical equipment and surgical techniques have enabled solo surgery, wherein a surgeon operates alone without the participation of other surgical members. However, the application of solo surgery in single-port laparoscopic surgery (SPLS) has been rarely reported. Prospectively collected databases of 60 patients who underwent solo-SPLS for appendicitis between March 2013 and June 2014 were retrospectively reviewed. Making a transumbilical incision into the peritoneal cavity was facilitated by using a Lone Star self-retaining retractor. After the establishment of a single port through the umbilicus, we installed a mechanical adjustable camera holder (Endoworld®LAP53 Holding Systems). It was anchored to the operating table rail and firmly held the laparoscope with a possibility to adjust the same as required by the operator. The operative method was identical to the SPLS appendectomy, except for the use of these instruments. The median operation time was 50 min (25-120). None of the patients required open conversion, insertion of an additional port or help of a human assistant. The median length of hospital stay for all patients was 1.0 day (range: 1-3 days). The median dosage of required intravenous analgesics (ketorolac, 0.1 mg/kg of body weight) was 0.0 ampoule (0-4). The median interval to initiation of solid diet was 1 day (1-2). The incidence of postoperative complications was 8.3% (5/60). Our results shows that solo-SPLS appendectomy could be performed without increasing operation time or postoperative complications when performed by a surgeon competent in performing SPLS appendectomy. Copyright © 2015. Published by Elsevier Ltd.

  7. Intracorporeal hybrid single port vs conventional laparoscopic appendectomy in children

    Directory of Open Access Journals (Sweden)

    Paul Anthony Karam

    2016-12-01

    Full Text Available Transumbilical laparoscopic assisted appendectomy combines laparoscopic single port dissection with open appendectomy after exteriorization of the appendix through the port site. Compared to the conventional three-port approach, this technique provides an alternative with excellent cosmetic outcome. We developed a safe and effective technique to perform an intracorporeal single port appendectomy, using the same laparoscope employed in the extracorporeal procedure. Retrospective review of 71 consecutively performed intracorporeal single port appendectomies and 30 conventional three-port appendectomies in children 6 to 17 years of age. A straight 10-mm Storz telescope with inbuilt 6 mm working channel is used to dissect the appendix, combined with one port-less 2.3 mm percutaneous grasper. Polymer WECK® hem-o-lock® clips are applied to seal the base of the appendix and the appendiceal vessels. No intraoperative complications were reported with the hybrid intracorporeal single port appendectomy or three-port appendectomy. There were two post-operative complications in the group treated with the single port hybrid technique: one intra-abdominal abscess and one surgical site infection. Groups did not differ in age, weight, and types of appendicitis. Operative times were shorter for the hybrid technique (70 vs 79 minutes but did not differ significantly (P=0.19. This modified technique to a previously described single port extracorporeal appendectomy is easy to master and implement. It provides exposure similar to a three-port laparoscopic appendectomy, while maintaining virtually scarless results and potentially reduces the risk for surgical site infections compared to the extracorporeal technique.

  8. Eigenfunction statistics for Anderson model with Hölder continuous ...

    Indian Academy of Sciences (India)

    We consider random Schrödinger operators on l 2 ( Z d ) with α -Hölder continuous ( 0 < α ≤ 1 ) single site distribution. In localized regime, we study the distribution of eigenfunctions in space and energy simultaneously. In a certain scaling limit, we prove limit points are Poisson.

  9. Menstrual cups and sanitary pads to reduce school attrition, and sexually transmitted and reproductive tract infections: a cluster randomised controlled feasibility study in rural Western Kenya

    NARCIS (Netherlands)

    Phillips-Howard, Penelope A.; Nyothach, Elizabeth; ter Kuile, Feiko O.; Omoto, Jackton; Wang, Duolao; Zeh, Clement; Onyango, Clayton; Mason, Linda; Alexander, Kelly T.; Odhiambo, Frank O.; Eleveld, Alie; Mohammed, Aisha; van Eijk, Anna M.; Edwards, Rhiannon Tudor; Vulule, John; Faragher, Brian; Laserson, Kayla F.

    2016-01-01

    Conduct a feasibility study on the effect of menstrual hygiene on schoolgirls' school and health (reproductive/sexual) outcomes. 3-arm single-site open cluster randomised controlled pilot study. 30 primary schools in rural western Kenya, within a Health and Demographic Surveillance System. Primary

  10. The mass and age of the first SONG target

    DEFF Research Database (Denmark)

    Frandsen, S.; Andersen, M. Fredslund; Brogaard, K.

    2018-01-01

    possibilities for ground-based asteroseismology of solar-like oscillations with a fully robotic network have been illustrated with the results obtained from just a single site of the SONG network. The window function is still a severe problem which will be solved when there are more nodes in the network....

  11. First comprehensive inventory of a tropical site for a megadiverse group of insects, the true flies (Diptera)

    Science.gov (United States)

    Tropical insect biodiversity remains largely unknown for most research sites in the world, due to the overwhelming number of species and lack of focus by taxonomists. Single-site studies are necessary, however to establish baselines for comparative studies across space, and as the basis for ecologic...

  12. A simple approximation method for dilute Ising systems

    International Nuclear Information System (INIS)

    Saber, M.

    1996-10-01

    We describe a simple approximate method to analyze dilute Ising systems. The method takes into consideration the fluctuations of the effective field, and is based on a probability distribution of random variables which correctly accounts for all the single site kinematic relations. It is shown that the simplest approximation gives satisfactory results when compared with other methods. (author). 12 refs, 2 tabs

  13. Transumbilikal kolecystektomi

    DEFF Research Database (Denmark)

    Al-Tayar, Haytham Abdelredha Hamid; Nielsen, Paula Edeusa Cristina; Jørgensen, Lars Nannestad

    2010-01-01

    Recent development of minimally invasive surgery has raised interest in laparoscopic surgery through a single abdominal incision. The most common names for this technique is single incisional laparoscopic surgery (SILS) or laparoscopic endoscopic single-site surgery (LESS). This article describes...

  14. An efficient hybrid, nanostructured, epoxidation catalyst: titanium silsesquioxane-polystyrene copolymer supported on SBA-15

    NARCIS (Netherlands)

    Santen, van R.A.; Zhang, Lei; Abbenhuis, H.C.L.; Gerritsen, G.; Ní Bhriain, N.M.; Magusin, P.C.M.M.; Mezari, B.; Han, W.; Yang, Q.; Li, Can

    2007-01-01

    A novel interfacial hybrid epoxidation catalyst was designed with a new immobilization method for homogeneous catalysts by coating an inorganic support with an organic polymer film containing active sites. The titanium silsesquioxane (TiPOSS) complex, which contains a single-site titanium active

  15. 20 CFR 639.3 - Definitions.

    Science.gov (United States)

    2010-04-01

    ...), the single site of employment to which they are assigned as their home base, from which their work is..., including part-time employees, who in the aggregate work at least 4,000 hours per week, exclusive of hours... wholly or partially owned by a parent company are treated as separate employers or as a part of the...

  16. Mapping important nucleotides in the peptidyl transferase centre of 23 S rRNA using a random mutagenesis approach

    DEFF Research Database (Denmark)

    Porse, B T; Garrett, R A

    1995-01-01

    Random mutations were generated in the lower half of the peptidyl transferase loop in domain V of 23 S rRNA from Escherichia coli using a polymerase chain reaction (PCR) approach, a rapid procedure for identifying mutants and a plasmid-based expression system. The effects of 21 single-site mutati...

  17. Characterization of the functional epitope on the urokinase receptor. Complete alanine scanning mutagenesis supplemented by chemical cross-linking

    DEFF Research Database (Denmark)

    Gårdsvoll, Henrik; Gilquin, Bernard; Le Du, Marie Hélène

    2006-01-01

    a comprehensive alanine scanning mutagenesis of uPAR combined with low resolution distance constraints defined within the complex using chemical cross-linkers as molecular rulers. The kinetic rate constants for the interaction between pro-uPA and 244 purified uPAR mutants with single-site replacements were...

  18. Online CTE in the Community College

    Science.gov (United States)

    Garza Mitchell, Regina L.; Etshim, Rachal; Dietz, Brian T.

    2016-01-01

    This single-site case study explored how one community college integrated online education into CTE courses and programs. Through semi-structured interviews and document analysis, the study explores how one college integrated online education (fully online, hybrid, and web-enhanced) into areas typically considered "hands-on".…

  19. 75 FR 17692 - Foreign-Trade Zone 82; Application for Subzone Authority; ThyssenKrupp Steel and Stainless USA...

    Science.gov (United States)

    2010-04-07

    ... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [Docket 51-2008] Foreign-Trade Zone 82..., many existing facilities are ``mini-mills'' and have less integration at a single site. Product may... addressed to the Board's Executive Secretary at: Foreign-Trade Zones Board, U.S. Department of Commerce...

  20. Randomized, Controlled Trial of Atomoxetine for Attention-Deficit/Hyperactivity Disorder in Adolescents with Substance Use Disorder

    Science.gov (United States)

    Thurstone, Christian; Riggs, Paula D.; Salomonsen-Sautel, Stacy; Mikulich-Gilbertson, Susan K.

    2010-01-01

    Objective: To evaluate the effect of atomoxetine hydrochloride versus placebo on attention-deficit/hyperactivity disorder (ADHD) and substance use disorder (SUD) in adolescents receiving motivational interviewing/cognitive behavioral therapy (MI/CBT) for SUD. Method: This single-site, randomized, controlled trial was conducted between December…

  1. THE SCHOOL PARK.

    Science.gov (United States)

    FISCHER, JOHN H.

    TO ASSIST IN DESEGREGATION, VARIOUS MODELS FOR THE SCHOOL PARK ARE PROPOSED--(1) ASSEMBLING ALL STUDENTS AND SCHOOLS OF A SMALL OR MEDIUM-SIZED COMMUNITY ON A SINGLE CAMPUS, (2) SERVING ONE SECTION OF A LARGE CITY, (3) CENTERING ALL SCHOOL FACILITIES FOR A SINGLE LEVEL OF EDUCATION ON A SINGLE SITE, AND (4) ESTABLISHING RINGS OF SCHOOL PARKS ABOUT…

  2. THE DISTRIBUTION AND SPREAD OF ALIEN VASCULAR PLANTS ...

    African Journals Online (AJOL)

    Surveys of alien plants at subantarctic Prince Edward Island in 2001 show that the ranges of all three introduced species have increased since the last survey in 1998. Poa annua, the longest-established species, increased its range substantially after 1987, prior to which it was confined to a single site for more than 20 years ...

  3. Understanding the Hydro-metathesis Reaction of 1-decene by Using Well-defined Silica Supported W, Mo, Ta Carbene/Carbyne Complexes

    KAUST Repository

    Saidi, Aya; Samantaray, Manoja; Tretiakov, Mykyta; Kavitake, Santosh Giridhar; Basset, Jean-Marie

    2017-01-01

    Direct conversion of 1-decene to petroleum range alkanes was obtained using hydro-metathesis reaction. To understand this reaction we employed three different well-defined single site catalysts precursors; [(≡Si-O-)W(CH3)5] 1, [(≡Si-O-)Mo(≡CtBu)(CH2

  4. Metathesis of alkanes and related reactions

    KAUST Repository

    Basset, Jean-Marie; Copé ret, Christophe; Soulivong, Daravong; Taoufik, Mostafa; Thivolle-Cazat, Jean

    2010-01-01

    , the process proceeds at relatively low temperature (ambient conditions or higher). It was discovered through the use of a silica-supported tantalum hydride, (=SiO)2TaH, a multifunctional catalyst with a single site of action. This reaction completes the story

  5. H-H interactions in Pd

    DEFF Research Database (Denmark)

    Christensen, O. B.; Ditlevsen, Peter; Jacobsen, Karsten Wedel

    1989-01-01

    -medium theory to calculate total energies we show the same tendency for the short-range part of the H-H interaction when two H atoms are squeezed into a single site in Pd or PdH. At longer range (of the order a lattice constant) there is an attractive, lattice-mediated H-H interaction. On the basis...

  6. Building Bridges between Technology and Content Literacy in Special Education: Lessons Learned from Special Educators' Use of Integrated Technology and Perceived Benefits for Students

    Science.gov (United States)

    Ciampa, Katia

    2017-01-01

    This single-site case study describes the outcomes and lessons learned from the implementation of a technology professional development initiative aimed at helping three special education teachers from an urban elementary school learn how to infuse technology in their content literacy instruction. Three types of qualitative data were collected:…

  7. Single-atom-resolved fluorescence imaging of an atomic Mott insulator

    DEFF Research Database (Denmark)

    Sherson, Jacob; Weitenberg, Christof; Andres, Manuel

    2010-01-01

    in situ images of a quantum fluid in which each underlying quantum particle is detected. Here we report fluorescence imaging of strongly interacting bosonic Mott insulators in an optical lattice with single-atom and single-site resolution. From our images, we fully reconstruct the atom distribution...

  8. An inverted repeat motif stabilizes binding of E2F and enhances transcription of the dihydrofolate reductase gene

    DEFF Research Database (Denmark)

    Wade, M; Blake, M C; Jambou, R C

    1995-01-01

    consensus E2F site, significantly decrease the binding stability of all of the forms of E2F tested. The rate of association of E2F-1/DP-1 heterodimers with the inverted repeat wild type site was not significantly different from those with the two single site mutated probes. Furthermore, the mutations...

  9. Traditional-Aged College Juniors' Career Planning Self-Efficacy: A Case Study

    Science.gov (United States)

    Sherman, Dawn C.

    2012-01-01

    The purpose of this single-site case study was to explore and describe traditional-age college juniors' reports of self-efficacy (Bandura, 1997) regarding Career Planning (Barker & Kellen, 1998). More specifically, the career planning confidence levels of college juniors enrolled in a required career development course at a private business…

  10. Three Advantages of Cross-National Comparative Ethnography--Methodological Reflections from a Study of Migrants and Minority Ethnic Youth in English and Spanish Schools

    Science.gov (United States)

    Jørgensen, Clara Rübner

    2015-01-01

    This paper discusses the strengths of using ethnographic research methods in cross-national comparative research. It focuses particularly on the potential of applying such methods to the study of migrants and minority ethnic youth in education, where large-scale quantitative studies or single-sited ethnographies are currently dominant. By linking…

  11. Comparative, Diachronic, Ethnographic Research on Education

    Science.gov (United States)

    Tobin, Joseph

    2014-01-01

    Most qualitative studies in international education take place in a single site in a single nation. When studies are of more than one country, they most often use more quantitative than qualitative approaches. Beatrice and John Whiting conducted the most systematic of comparative cross-cultural studies of child rearing in their "Six…

  12. Proceedings – Mathematical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Recent results on localization, both exponential and dynamical, for various models of one-dimensional, continuum, random Schrödinger operators are reviewed. This includes Anderson models with indefinite single site potentials, the Bernoulli–Anderson model, the Poisson model, and the random displacement model.

  13. Activity and Selectivity for O-2 Reduction to H2O2 on Transition Metal Surfaces

    DEFF Research Database (Denmark)

    Siahrostami, Samira; Verdaguer Casadevall, Arnau; Karamad, Mohammadreza

    2013-01-01

    Industrially viable electrochemical production of H2O2 requires active, selective and stable electrocatalyst materials to catalyse the oxygen reduction reaction to H2O2. On the basis of density functional theory calculations, we explain why single site catalysts such as Pd/Au show improved...

  14. The Relationship between Reports of Psychological Capital and Reports of Job Satisfaction among Administrative Personnel at a Private Institution of Higher Education

    Science.gov (United States)

    Mello, James A.

    2012-01-01

    The purpose of this single-site case study was to investigate the relationship between administrative personnel's reports of psychological capital (Luthans, Youssef, & Avolio, 2007) and their reports of job satisfaction (Hackman & Oldham, 1980). Specifically, two surveys, the Psychological Capital Questionnaire (Luthans, Youssef, &…

  15. Effect of benzimidazole fungicides and calcium chloride on ...

    African Journals Online (AJOL)

    SERVER

    2007-06-04

    Jun 4, 2007 ... Botrytis cinerea (Besri and Diatta, 1985; Hmouni et al.,. 1996). It is very likely that the repetitive uses of these systemic fungicides and their persistence during long periods of conservation (Ben Arie, 1975; Prusky, 1985) have led to considerable selective pressure on both species. Moreover, the single site ...

  16. A well-defined silica-supported aluminium alkyl through an unprecedented, consecutive two-step protonolysis–alkyl transfer mechanism

    KAUST Repository

    Pelletier, Jé ré mie; Espinas, Jeff; Vu, Nghiem; Norsic, Sé bastien; Baudouin, Anne; Delevoye, Laurent; Tré bosc, Julien; Le Roux, Erwan; Santini, Catherine; Basset, Jean-Marie; Gauvin, Ré gis M.; Taoufik, Mostafa

    2011-01-01

    Impregnation of [(AliBu3)(Et2O)] on partially dehydroxylated SBA-15 affords a mesoporous material bearing the well-defined single site surface aluminium species [(≡SiO)2Al(iBu)(Et 2O)]. © The Royal Society of Chemistry.

  17. Describing an Environment for a Self-Sustaining Technology Transfer Service in a Small Research Budget University: A Case Study

    Science.gov (United States)

    Nieb, Sharon Lynn

    2014-01-01

    This single-site qualitative study sought to identify the characteristics that contribute to the self sustainability of technology transfer services at universities with small research budgets through a case study analysis of a small research budget university that has been operating a financially self-sustainable technology transfer service for…

  18. Mott Transition of Cerium Compound CeCu2Si2 in the Anderson ...

    African Journals Online (AJOL)

    The Exact-Diagonalization (ED) technique is applied to the Single Site Impurity Anderson Model (SIAM) and the Periodic Anderson Model (PAM) to elucidate the nature of the ground-state energy and the phase diagram of the two models. The results obtained show a smooth phase transition from an antiferromagnetic ...

  19. Flora of Chihuahuan desertscrub on limestone in northeastern Sonora, Mexico

    Science.gov (United States)

    Thomas R. Van Devender; Ana Lilia Reina-Guerrero; J. Jesus. Sanchez-Escalante

    2013-01-01

    Transects were done in desertscrub on limestone to characterize the flora of the westernmost Chihuahuan Desert. Most of the sites (15) were in the Municipios of Agua Prieta and Naco in northeastern Sonora, with single sites near Ascensión, northwestern Chihuahua and east of Douglas in southeastern Arizona. A total of 236 taxa were recorded on transects. Dicot perennial...

  20. Control and Characterization of Titanium Dioxide Morphology: Applications in Surface Organometallic Chemistry

    KAUST Repository

    Jeantelot, Gabriel

    2014-01-01

    metal oxide supports such as amorphous silica (SiO2) and γ-alumina (Al2O3). In this thesis, we sought to enable the use of titania (TiO2) as a new support for single-site well-defined grafting of metal complexes. This was achieved by synthesizing a

  1. STEM Faculty and Indirect Costs: What Administrators Need to Know

    Science.gov (United States)

    Gossman, Susan

    2016-01-01

    The focus of this single site, qualitative case study was on public research university STEM (science, technology, engineering and mathematics) faculty and their perspectives on, and behavior towards, indirect cost recovery. The explanatory scheme was derived from anthropological theory and incorporated organizational culture, resource dependency…

  2. Equity at Scale: How Public Charter School Networks Can Innovate and Improve Services for Students with Disabilities

    Science.gov (United States)

    O'Neill, Paul T.; Rhim, Lauren Morando

    2015-01-01

    When public charter schools first opened in the early 1990s, each was unique and independent. But as successful public charter schools continued to grow and expand their impact beyond a single site, and as organizations developed school designs that could be implemented at multiple locations, networks of public charter schools emerged. The public…

  3. Third Culture Kids and College Support: A Case Study

    Science.gov (United States)

    Holdren, Sarah Jennifer

    2013-01-01

    This single site case study applies the "Transition Cycle" framework (Pollock & Van Reken, 2009) to an institutionally-based, student-run support program for Third Culture Kids. The purpose of this study was to examine how Lewis and Clark College responded to the presence of Third Culture Kid, or Global Nomad, students on campus by…

  4. Center for Cancer Research plays key role in first FDA-approved drug for treatment of Merkel cell carcinoma | Center for Cancer Research

    Science.gov (United States)

    The Center for Cancer Research’s ability to rapidly deploy integrated basic and clinical research teams at a single site facilitated the rapid FDA approval of the immunotherapy drug avelumab for metastatic Merkel cell carcinoma, a rare, aggressive form of skin cancer. Learn more...  

  5. Continuity of Integrated Density of States - Independent Randomness

    Indian Academy of Sciences (India)

    In this paper we discuss the continuity properties of the integrated density of states for random models based on that of the single site distribution. Our results are valid for models with independent randomness with arbitrary free parts. In particular in the case of the Anderson type models (with stationary, growing, decaying ...

  6. Opportunities and costs for preventing vertebrate extinctions

    DEFF Research Database (Denmark)

    Conde, Dalia Amor; Colchero, Fernando; Güneralp, Burak

    2015-01-01

    -oriented organisations that aims to protect Critically Endangered and Endangered species restricted to single sites, has identified 920 species of mammals, birds, amphibians, reptiles, conifers and reef-building corals in 588 ‘trigger’ sites [3] . These are arguably the most irreplaceable category of important...

  7. Surgery in biliary lithiasis: from the traditional "open" approach to laparoscopy and the "rendezvous" technique.

    Science.gov (United States)

    Tarantino, Giuseppe; Magistri, Paolo; Ballarin, Roberto; Assirati, Giacomo; Di Cataldo, Antonio; Di Benedetto, Fabrizio

    2017-12-15

    According to the current literature, biliary lithiasis is a worldwide-diffused condition that affects almost 20% of the general population. The rate of common bile duct stones (CBDS) in patients with symptomatic cholelithiasis is estimated to be 10% to 33%, depending on patient's age. Compared to stones in the gallbladder, the natural history of secondary CBDS is still not completely understood. It is not clear whether an asymptomatic choledocholithiasis requires treatment or not. For many years, open cholecystectomy with choledochotomy and/or surgical sphincterotomy and cleaning of the bile duct were the gold standard to treat both pathologies. Development of both endoscopic retrograde cholangiopancreatography (ERCP) and laparoscopic surgery, together with improvements in diagnostic procedures, influenced new approaches to the management of CBDS in association with gallstones. We decided to systematically review the literature in order to identify all the current therapeutic options for CBDS. A systematic literature search was performed independently by two authors using PubMed, EMBASE, Scopus and the Cochrane Library Central. The therapeutic approach nowadays varies greatly according to the availability of experience and expertise in each center, and includes open or laparoscopic common bile duct exploration, various combinations of laparoscopic cholecystectomy and ERCP and combined laparoendoscopic rendezvous. Although ERCP followed by laparoscopic cholecystectomy is currently preferred in the majority of hospitals worldwide, the optimal treatment for concomitant gallstones and CBDS is still under debate, and greatly varies among different centers. Copyright © 2017 The Editorial Board of Hepatobiliary & Pancreatic Diseases International. Published by Elsevier B.V. All rights reserved.

  8. Endoscopic retrograde cholangiopancreatography with rendezvous cannulation reduces pancreatic injury.

    Science.gov (United States)

    Swahn, Fredrik; Regnér, Sara; Enochsson, Lars; Lundell, Lars; Permert, Johan; Nilsson, Magnus; Thorlacius, Henrik; Arnelo, Urban

    2013-09-28

    To examine whether rendezvous endoscopic retrograde cholangiopancreatography (ERCP) is associated with less pancreatic damage, measured as leakage of proenzymes, than conventional ERCP. Patients (n = 122) with symptomatic gallstone disease, intact papilla and no ongoing inflammation, were prospectively enrolled in this case-control designed study. Eighty-one patients were subjected to laparoscopic cholecystectomy and if intraoperative cholangiography suggested common bile duct stones (CBDS), rendezvous ERCP was performed intraoperatively (n = 40). Patients with a negative cholangiogram constituted the control group (n = 41). Another 41 patients with CBDS, not subjected to surgery, underwent conventional ERCP. Pancreatic proenzymes, procarboxypeptidase B and trypsinogen-2 levels in plasma, were analysed at 0, 4, 8 and 24 h. The proenzymes were determined in-house with a double-antibody enzyme linked immunosorbent assay. Pancreatic amylase was measured by an enzymatic colourimetric modular analyser with the manufacturer's reagents. All samples were blinded at analysis. Post ERCP pancreatitis (PEP) occurred in 3/41 (7%) of the patients cannulated with conventional ERCP and none in the rendezvous group. Increased serum levels indicating pancreatic leakage were significantly higher in the conventional ERCP group compared with the rendezvous ERCP group regarding pancreatic amylase levels in the 4- and 8-h samples (P = 0.0015; P = 0.03), procarboxypeptidase B in the 4- and 8-h samples (P rendezvous cannulation technique compared with patients that underwent cholecystectomy alone (control group). Post procedural concentrations of pancreatic amylase and procarboxypeptidase B were significantly correlated with pancreatic duct cannulation and opacification. Rendezvous ERCP reduces pancreatic enzyme leakage compared with conventional ERCP cannulation technique. Thus, laparo-endoscopic technique can be recommended with the ambition to minimise the risk for post ERCP

  9. Perception versus reality: elucidating motivation and expectations of current fellowship council minimally invasive surgery fellows.

    Science.gov (United States)

    Watkins, Jeffrey R; Pryor, Aurora D; Truitt, Michael S; Jeyarajah, D Rohan

    2018-04-17

    The aim of our study is to determine minimally invasive trainee motivation and expectations for their respective fellowship. Minimally Invasive Surgery (MIS) is one of the largest non-ACGME post-residency training pathways though little is known concerning the process of residents choosing MIS as a fellowship focus. As general surgery evolves, it is important to understand resident motivation in order to better prepare them for a surgical career. A survey invitation was sent to current trainees in the Minimally Invasive and related pathways through the Fellowship Council. The participants were asked to complete a web-based questionnaire detailing demographics, experiences preparing for fellowship, motivation in choosing an MIS fellowship, and expectations for surgical practice after fellowship. Sixty-seven MIS trainees responded to the survey out of 151 invitations (44%). The Fellowship Council website, mentors, and other fellows were cited as the most helpful source of information when applying for fellowship. Trainees were active in surgical societies as residents, with 78% having membership in the ACS and 60% in SAGES. When deciding to pursue MIS as a fellowship, the desire to increase laparoscopic training was the most important factor. The least important reasons cited were lack of laparoendoscopic training in residency and desire to learn robotic surgery. The majority of trainees believed their laparoscopic skill set was above that of their residency cohort (81%). The most desired post-fellowship employment model is hospital employee (46%) followed by private practice (27%). Most fellows plan on marketing themselves as MIS surgeons (90%) or General Surgeons (78%) when in practice. Residents who choose MIS as a fellowship have a strong exposure to laparoscopy and want to become specialists in their field. Mentors and surgical societies including ACS and SAGES play a vital role in preparing residents for fellowship and practice.

  10. Laparoscopic Choledochoduodenostomy.

    Science.gov (United States)

    Cuendis-Velázquez, Adolfo; E Trejo-Ávila, Mario; Rosales-Castañeda, Enrique; Cárdenas-Lailson, Eduardo; E Rojano-Rodríguez, Martin; Romero-Loera, Sujey; A Sanjuan-Martínez, Carlos; Moreno-Portillo, Mucio

    Today's options for biliary bypass procedures, for difficult choledocholithiasis, range from open surgery to laparo-endoscopic hybrid procedures. The aim of this study was to analyze the outcomes of patients with difficult choledocholithiasis treated with laparoscopic choledochoduodenostomy. We performed a prospective observational study from March 2011 to June 2016. We included patients with difficult common bile duct stones (recurrent or unresolved by ERCP) in which a biliary bypass procedure was required. We performed a laparoscopic bile duct exploration with choledochoduodenostomy and intraoperative cholangioscopy. A total of 19 patients were included. We found female predominance (78.9%), advanced mean age (72.4±12 years) and multiple comorbidities. Most patients with previous episodes of choledocholitiasis or cholangitis, mode 1 (min-max: 1-7). Mean common bile duct diameter 24.9±7mm. Mean operative time 218.5±74min, estimated blood loss 150 (30-600)mL, resume of oral intake 3.2±1 days, postoperative length of stay 4.9±2 days. We found a median of 18 (12-32) months of follow-up. All patients with normalization of liver enzymes during follow-up. One patient presented with sump syndrome and one patient died due to nosocomial pneumonia. Laparoscopic choledochoduodenostomy with intraoperative cholangioscopy seems to be safe and effective treatment for patients with difficult common bile duct stones no resolved by endoscopic procedures. This procedure is a good option for patients with advanced age and multiple comorbidities. We offer all the advantages of minimally invasive surgery to these patients. Copyright © 2017 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

  11. [Intraoperative choledochoscopy usefulness in the treatment of difficult biliary stones].

    Science.gov (United States)

    Cuendis-Velázquez, A; Rojano-Rodríguez, M E; Morales-Chávez, C E; González Angulo-Rocha, A; Fernández-Castro, E; Aguirre-Olmedo, I; Torres-Ruiz, M F; Orellana-Parra, J C; Cárdenas-Lailson, L E

    2014-01-01

    Choledocholithiasis presents in 5-10% of the patients with biliary lithiasis. Numerous treatment algorithms have been considered for this disease, however, up to 10% of these therapeutic procedures may fail. Intraoperative choledochoscopy has become a useful tool in the treatment of patients with difficult-to-manage choledocholithiasis. To determine the usefulness of intraoperative choledochoscopy in the laparoendoscopic treatment of difficult stones that was carried out in our service. A cross-sectional study was conducted. The case records were reviewed of the patients that underwent intraoperative choledochoscopy during biliary tree exploration plus laparoscopic choledochoduodenal anastomosis within the time frame of March 1, 2011 and May 31, 2012, at the Hospital General Dr. Manuel Gea González. Transabdominal choledochoscopies were performed with active stone extraction when necessary, followed by peroral choledochoscopies through the recently formed bilioenteric anastomosis. The data were analyzed with descriptive statistics and measures of central tendency. The mean age was 71 years, 57% of the patients were women, and the ASA III score predominated. Active extraction of stones with 7 to 35mm diameters was carried out in 4 of the cases and the absence of stones in the biliary tract was corroborated in all the patients. The mean surgery duration was 18 minutes (range: 4 to 45min). Choledochoscopy is a safe and effective minimally invasive procedure for the definitive treatment of difficult stones. Copyright © 2013 Asociación Mexicana de Gastroenterología. Published by Masson Doyma México S.A. All rights reserved.

  12. Lattice vibrations in K/sub c/Rb/sub 1-c/ alloys

    International Nuclear Information System (INIS)

    Kaplan, T.; Mostoller, M.; Gray, L.J.

    1985-01-01

    The authors have already studied this system theoretically using the mass defect coherent potential approximation (CPA) and the CPA-F. The deficiencies in the mass defect CPA and CPA-F theories have led them to apply a more sophisticated approximation which was developed by Kaplan, Leath, Gray and Diehl (KLGD). This approximation is a generalization of the CPA which is not restricted to single site averaging, but can include cluster scattering. More important, it can incorporate force constant changes without any restrictions. As a first application of KLGD, they have included nearest neighbor radial and tangential force constant changes with single site averaging. As in the previous cases, all longer range forces are included in a virtual crystal approximation. In this study they have not tried to fit the force constants. Instead they have used a pseudopotential approximation by Gruenewald and Scharnberg to determine the force constants in K-Rb alloys

  13. Isolation and characterization of fatty acid binding protein in the liver of the nurse shark, Ginglymostoma cirratum.

    Science.gov (United States)

    Bass, N M; Manning, J A; Luer, C A

    1991-01-01

    1. A 14.5 kDa fatty acid binding protein was isolated from the liver of the nurse shark, Ginglymostoma cirratum. 2. Purified shark liver FABP (pI = 5.4) bound oleic acid at a single site with an affinity similar to that of mammalian FABP. 3. The apparent size, pI and amino acid composition of shark liver FABP indicate a close structural relationship between this protein and mammalian heart FABP.

  14. Menstrual cups and sanitary pads to reduce school attrition, and sexually transmitted and reproductive tract infections: a cluster randomised controlled feasibility study in rural Western Kenya

    OpenAIRE

    Phillips-Howard, Penelope; Nyothach, Elizabeth; terKuile, Feiko; Omoto, Jackton; Wang, Duolao; Zeh, Clement; Onyango, Clayton; Mason, Linda; Alexander, Kelly T; Odhiambo, Frank; Eleveld, Alie; Mohammed, Aisha; vanEijk, Anna; Tudor Edwards, Rhiannon; Vulule, John

    2016-01-01

    Objectives Conduct a feasibility study on the effect of menstrual hygiene on schoolgirls' school and health (reproductive/sexual) outcomes. Design 3-arm single-site open cluster randomised controlled pilot study. Setting 30 primary schools in rural western Kenya, within a Health and Demographic Surveillance System. Participants Primary schoolgirls 14?16?years, experienced 3 menses, no precluding disability, and resident in the study area. Interventions 1 insertable menstrual cup, or monthly s...

  15. Accessing Remote Knowledge

    DEFF Research Database (Denmark)

    Maskell, Peter

    2014-01-01

    young, single-site firms search for distant sources of complementary competences. The discussion is positioned within a comprehensive framework that allows a systematic investigation of the approaches available to firms engaged in globally extended learning. By utilizing the distinction between problem...... awareness (what remote knowledge is needed?) and source awareness (where does this knowledge reside?) the article explores the relative merits and inherent limitations of pipelines, listening posts, crowdsourcing and trade fairs to acquire knowledge and solutions from geographically and relationally remote...

  16. Effect of Polarization on the Mobility of C60: A Kinetic Monte Carlo Study.

    Science.gov (United States)

    Volpi, Riccardo; Kottravel, Sathish; Nørby, Morten Steen; Stafström, Sven; Linares, Mathieu

    2016-02-09

    We present a study of mobility field and temperature dependence for C60 with Kinetic Monte Carlo simulations. We propose a new scheme to take into account polarization effects in organic materials through atomic induced dipoles on nearby molecules. This leads to an energy correction for the single site energies and to an external reorganization happening after each hopping. The inclusion of polarization allows us to obtain a good agreement with experiments for both mobility field and temperature dependence.

  17. 76 FR 48207 - Federal Implementation Plans: Interstate Transport of Fine Particulate Matter and Ozone and...

    Science.gov (United States)

    2011-08-08

    ..., or disruptions in electricity supply from other units or from the transmission grid. As a consequence... ([micro]g/m\\3\\) and the greatest reduction at a single site is 3.60 [micro]g/m\\3\\. For 24-hour PM 2.5 , the average reduction across all monitoring sites in covered states in 2014 is 4.3 [micro]g/ m\\3\\ and...

  18. Deficiency tracking system, conceptual business process requirements

    Energy Technology Data Exchange (ETDEWEB)

    Hermanson, M.L.

    1997-04-18

    The purpose of this document is to describe the conceptual business process requirements of a single, site-wide, consolidated, automated, deficiency management tracking, trending, and reporting system. This description will be used as the basis for the determination of the automated system acquisition strategy including the further definition of specific requirements, a ''make or buy'' determination and the development of specific software design details.

  19. Investing in Threatened Species Conservation: Does Corruption Outweigh Purchasing Power?

    OpenAIRE

    Garnett, Stephen T.; Joseph, Liana N.; Watson, James E. M.; Zander, Kerstin K.

    2011-01-01

    In many sectors, freedom in capital flow has allowed optimization of investment returns through choosing sites that provide the best value for money. These returns, however, can be compromised in countries where corruption is prevalent. We assessed where the best value for money might be obtained for investment in threatened species that occur at a single site, when taking into account corruption. We found that the influence of corruption on potential investment decisions was outweighed by th...

  20. Biotypes of scentless chamomile Matricaria maritima (L.) ssp. inodora (L.) Dostal and common poppy Papaver rhoeas (L.) resistant to tribenuron methyl, in Poland

    OpenAIRE

    Adamczewski Kazimierz; Kierzek Roman; Matysiak Kinga

    2014-01-01

    Scentless chamomile Matricaria maritima (L.) ssp. inodora (L.) Dostal and common poppy Papaver rhoeas (L.) are species which very often infest winter cereal and winter rape crops. Inhibitors of acetolactate synthase (ALS) are commonly used for control of these weeds. The herbicides are characterised by a single site of action in the plant, which has an influence on selection of the weed population and may result in a rapid development of resistance. In 2012, five seed samples of scen...

  1. Deficiency tracking system, conceptual business process requirements

    International Nuclear Information System (INIS)

    Hermanson, M.L.

    1997-01-01

    The purpose of this document is to describe the conceptual business process requirements of a single, site-wide, consolidated, automated, deficiency management tracking, trending, and reporting system. This description will be used as the basis for the determination of the automated system acquisition strategy including the further definition of specific requirements, a ''make or buy'' determination and the development of specific software design details

  2. Second order phase transition in two dimensional sine-Gordon field theory - lattice model

    International Nuclear Information System (INIS)

    Babu Joseph, K.; Kuriakose, V.C.

    1978-01-01

    Two dimensional sine-Gordon (SG) field theory on a lattice is studied using the single-site basis variational method of Drell and others. The nature of the phase transition associated with the spontaneous symmetry breakdown in a SG field system is clarified to be of second order. A generalisation is offered for a SG-type field theory in two dimensions with a potential of the form [cossup(n)((square root of lambda)/m)phi-1].(author)

  3. It is the team that makes the success; Das Team macht den Erfolg

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, J.P.

    2008-05-19

    Handmade solar collectors are a thing of the past. Industrial processes and modern production techniques like Kanban and Kaizen have become the rule rather than an exception. Viessmann, the world's number two producer (see Sun and Wind Energy 4/2007), constructed a new production unit at Faulquemont in the French region of Lorraine. Viessmann is the only producer capable of constructing highly selective coatings, thus combining all production stages in a single site. (orig.)

  4. FIRST RECORDS OF THE INVASIVE AMERICAN WASP ISODONTIA MEXICANA (HYMENOPTERA: SPHECIDAE) IN SERBIA

    OpenAIRE

    Ćetković, Aleksandar; Čubrilović, Branka; Plećaš, Milan; Popović, Anđelka; Savić, Dragiša; Stanisavljević, Ljubiša

    2012-01-01

    The first verified occurrences of the invasive American sphecid wasp, Isodontia mexicana (Saussure, 1867), in Serbia are reported. It was first collected from a trap-nest sample in the northern surroundings of Belgrade in 2010. During 2012, we recorded well-established, abundant populations in the central city area of Belgrade, its surroundings, and also at a single site on the Fruška Gora Mt. We briefly review the circumstances and course of its recent eastward and northeastward spreading in...

  5. Effects of surface and bulk transverse fields on critical behaviour of ferromagnetic films

    International Nuclear Information System (INIS)

    Saber, A.; Lo Russo, S.; Mattei, G.

    2002-02-01

    The influence of surface and bulk transverse fields on the critical behaviour of a ferromagnetic Ising film is studied using the effective field theory based on a single-site cluster method. Surface exchange enhancement is considered and a critical value is obtained. The dependence of the critical uniform transverse field on film thickness, phase diagrams in the fields, critical surface transverse field versus the bulk one, and exchange coupling ratio are presented. (author)

  6. Heller myotomy for achalasia. From the open to the laparoscopic approach.

    Science.gov (United States)

    Allaix, Marco E; Patti, Marco G

    2015-07-01

    The last three decades have witnessed a progressive evolution in the surgical treatment of esophageal achalasia, with a shift from open to a minimally invasive Heller myotomy. The laparoscopic approach is currently the standard of care with better short-term outcomes and similar long-term functional results when compared to open surgery. More recently, the laparoscopic single-site approach and the use of the robot have been proposed to further improve the surgical outcome in achalasia patients.

  7. Establishing a Research and Evaluation Capability for the Joint Medical Education and Training Campus

    OpenAIRE

    Kirby, Sheila Nataraj; Marsh, Julie A.; Thie, Harry J.

    2011-01-01

    In calling for the transformation of military medical education and training, the 2005 Base Realignment and Closure Commission recommended relocating basic and specialty enlisted medical training to a single site to take advantage of economies of scale and the opportunity for joint training. As a result, a joint medical education and training campus (METC) has been established at Fort Sam Houston, Texas. Two of METC's primary long-term goals are to become a high-performing learning organizati...

  8. The Age of Enlightenment: Evolving Opportunities in Brain Research Through Optical Manipulation of Neuronal Activity

    OpenAIRE

    Jerome, Jason; Heck, Detlef H.

    2011-01-01

    Optical manipulation of neuronal activity has rapidly developed into the most powerful and widely used approach to study mechanisms related to neuronal connectivity over a range of scales. Since the early use of single site uncaging to map network connectivity, rapid technological development of light modulation techniques has added important new options, such as fast scanning photostimulation, massively parallel control of light stimuli, holographic uncaging, and two-photon stimulation techn...

  9. Mindfulness-Based Cognitive Therapy as a Treatment for Chronic Tinnitus: A Randomized Controlled Trial

    OpenAIRE

    McKenna, L.; Marks, E. M.; Hallsworth, C. A.; Schaette, R.

    2017-01-01

    BACKGROUND: Tinnitus is experienced by up to 15% of the population and can lead to significant disability and distress. There is rarely a medical or surgical target and psychological therapies are recommended. We investigated whether mindfulness-based cognitive therapy (MBCT) could offer an effective new therapy for tinnitus. METHODS: This single-site randomized controlled trial compared MBCT to intensive relaxation training (RT) for chronic, distressing tinnitus in adults. Both treatments in...

  10. Lung disease associated with progressive systemic sclerosis. Assessment of interlobar variation by bronchoalveolar lavage and comparison with noninvasive evaluation of disease activity

    International Nuclear Information System (INIS)

    Miller, K.S.; Smith, E.A.; Kinsella, M.; Schabel, S.I.; Silver, R.M.

    1990-01-01

    Progressive systemic sclerosis (PSS), or scleroderma, is a disease of unknown etiology that involves many organ systems, including the lungs. The interstitial lung disease of systemic sclerosis is becoming an increasing cause of morbidity and mortality. This process has been previously evaluated with single-site bronchoalveolar lavage (BAL), gallium scanning, pulmonary function testing, and, occasionally, by open lung biopsy. As BAL has been shown to correlate well with open lung biopsy in systemic sclerosis, we sought to determine if single-site BAL accurately reflects alveolitis in a second site in the lung, and if BAL results correlate with other noninvasive tests of lung inflammation: gallium uptake, chest radiography, or arterial blood gas analysis. We performed 17 studies in 13 patients with scleroderma and found no significant lobar differences in lavage results or gallium scanning. By our criteria for normal versus active alveolitis, only two of 17 patient lavages would have been classified as normal by one side and abnormal by the other side. Although percent gallium uptake was equal bilaterally and supported the concept of alveolitis uniformity, gallium uptake intensity did not correlate with activity as measured by BAL. Furthermore, chest radiograph and arterial blood gas analysis did not correlate with BAL results or gallium scanning. We believe these data support the suitability of single-site lavage in the investigation of systemic-sclerosis-associated alveolitis and diminish the importance of gallium scanning in the investigation of systemic sclerosis pulmonary disease

  11. Single versus Two-Site Phacoemulsification and Mitomycin-C Trabeculectomy

    Directory of Open Access Journals (Sweden)

    Alireza Baradaran-Rafiee

    2008-11-01

    Full Text Available

    PURPOSE: To compare the outcomes of single-site versus two-site mitomycin-C (MMC augmented phacotrabeculectomy. METHODS: This matched randomized clinical trial included 34 eyes of 30 patients with visually significant cataracts and poorly controlled glaucoma. Equal numbers of eyes were randomly assigned to the single-site and two-site groups. In the single-site approach, phacoemulsification was performed under a superior scleral tunnel followed by trabeculectomy. The two-site approach included a temporal clear corneal phaco-emulsification combined with a separate superior trabeculectomy. MMC 0.2 mg/ml was similarly applied for one minute in both groups. RESULTS: Patients were followed for a mean period of 13±1.4 (range, 12 to 15 months. Mean best corrected visual acuity one year after surgery was 0.6±0.4 LogMAR in the single-site group and 0.4±0.28 LogMAR in the two-site group (P=0.12. In the single-site group, mean preoperative intraocular pressure (IOP was 26.4±6.6 mmHg which was decreased to 14.8±2.5 mmHg, one year after the operation (P < 0.001. Corresponding figures for the two-site group were 22.9±3.3 and 13.6±1.7 mmHg respectively (P < 0.001. At final follow up no significant difference in IOP existed between the study groups. Mean number of anti-glaucoma medications was 0.06±0.24 in the two-site group vs 0

  12. NOTES: issues and technical details with introduction of NOTES into a small general surgery residency program.

    Science.gov (United States)

    Kavic, Michael S; Mirza, Brian; Horne, Walter; Moskowitz, Jesse B

    2008-01-01

    Natural orifice translumenal endoscopic surgery (NOTES) is a development of recent origin. In 2004, Kalloo et al first described NOTES investigation in an animal model. Since then, several investigators have pursued NOTES study in animal survival and nonsurvival models. Our objectives for this project included studying NOTES intervention in a laboratory environment using large animal (swine) models and learning to do so in a safe, controlled manner. Ultimately, we intend to introduce NOTES methodology into our surgical residency training program. The expertise of an experienced laparoscopic surgeon, fellowship-trained laparoendoscopic surgeon, and veterinarian along with a senior surgical resident was utilized to bring the input of several disciplines to this study. The Institutional Animal Care and Use Committee (IACUC) of Northeastern Ohio Universities College of Medicine and Pharmacy (NEOUCOM/COP) approved this study. A series of 5 laboratory sessions using mixed breed farm swine varying in weight from 37 kg to 43.1 kg was planned for the initial phase of NOTES introduction into our residency program. Animals were not kept alive in this investigation. All animals were anesthetized using a standard swine protocol and euthanized following guidelines issued by the American Veterinary Medical Association Panel on Euthanasia. Equipment included a Fujinon EVE endoscope 0.8 cm in diameter with a suction/irrigation channel and one working channel. Initially, a US Endoscopy gastric overtube, 19.5 mm OD and 50 cm in length, was used to facilitate passage of the endoscope. However, this device was found to have insufficient length. Subsequently, commercially available 5/8" diameter clear plastic tubing, 70 cm to 80 cm in length, was adapted for use as an overtube. Standard endoscopic instruments included Boston Scientific biopsy forceps, needle-knife, papillotome, endoscopic clip applier, and Valley Lab electrosurgical unit. A Karl Storz laparoscope and tower were used for

  13. Effect of dexmedetomidine on the stress reaction caused by sevoflurance anesthesia in school-age children with different personality characteristics

    Directory of Open Access Journals (Sweden)

    Juan Fan

    2017-02-01

    Full Text Available Objective: To observe the effect of dexmedetomidine on the stress reaction caused by sevoflurance anesthesia during the perianesthesia period in school-age children with different personality characteristics. Methods: A total of 160 children who were admitted in our hospital for transumbilical single-port laparoscopic hernia inner ring ligation were included in the study and randomized into dexmedetomidine (D group and midazolam (M group. The children were performed with Eysenck Personality Questionnaire before operation (children edition. Children were divided into the emotion group (group I and stable group (group II. The operation was performed under sevoflurance inhalation anesthesia. Patients in DI and DII groups were given 1 毺g/kg DEX, MI and MII groups were given 0.05 mg/kg midazolam, for 15 min. MAP and HR one day before operation (T0, before anesthesia induction (T1, 1 min after pneumoperitoneum establishment (T2, the time after pulling out the laryngeal mask (T3, and the time after shifting from the recovery room (T4 were recorded. A volume of 6 mL venous blood 1 d before operation and 4 h after operation was collected. Blood sugar concentration, cortisol and IL-6 levels were detected. Results: MAP at T1, T2, T3, and T4 in DI and MI groups were significantly elevated when compared with at T0. MAP at T2 and T3 in DII group was significantly elevated when compared with at T0. MAP at T2, T3, and T4 in MII group was significantly elevated when compared with at T0. When compared with DI group, MAP at T1, T2, and T3 in DII group was significantly reduced; MAP at T2, T3, and T4 in MI group was significantly elevated; MAP at T1 in MII group was significantly reduced. When compared with DII group, MAP at T2, T3, and T4 in MI and MII groups was significantly elevated. HR at T1, T2, T3, and T4 was significantly elevated when compared with at T0. When compared with DI group, HR at T1, T2, and T3 in DII group was significantly reduced; HR at each

  14. Quantum many-body dynamics of ultracold atoms in optical lattices

    Energy Technology Data Exchange (ETDEWEB)

    Kessler, Stefan

    2014-04-15

    Ultracold atoms can be trapped in periodic intensity patterns of light created by counterpropagating laser beams, so-called optical lattices. In contrast to its natural counterpart, electrons in a solid state crystal, this man-made setup is very clean and highly isolated from environmental degrees of freedom. Moreover, to a large extent, the experimenter has dynamical control over the relevant system parameters: the interaction between atoms, the tunneling amplitude between lattice sites, and even the dimensionality of the lattice. These advantages render this system a unique platform for the simulation of quantum many-body dynamics for various lattice Hamiltonians as has been demonstrated in several experiments by now. The most significant step in recent times has arguably been the introduction of single-site detection of individual atoms in optical lattices. This technique, based on fluorescence microscopy, opens a new doorway for the study of quantum many-body states: the detection of the microscopic atom configuration. In this thesis, we theoretically explore the dynamics of ultracold atoms in optical lattices for various setups realized in present-day experiments. Our main focus lies on aspects that become experimentally accessible by (realistic extensions of) the novel single-site measurement technique. The first part deals with the expansion of initially confined atoms in a homogeneous lattice, which is one way to create atomic motion in experiments. We analyze the buildup of spatial correlations during the expansion of a finitely extended band insulating state in one dimension. The numerical simulation reveals the creation of remote spin-entangled fermions in the strongly interacting regime. We discuss the experimental observation of such spin-entangled pairs by means of a single-site measurement. Furthermore, we suggest studying the impact of observations on the expansion dynamics for the extreme case of a projective measurement in the spatial occupation

  15. Quantum many-body dynamics of ultracold atoms in optical lattices

    International Nuclear Information System (INIS)

    Kessler, Stefan

    2014-01-01

    Ultracold atoms can be trapped in periodic intensity patterns of light created by counterpropagating laser beams, so-called optical lattices. In contrast to its natural counterpart, electrons in a solid state crystal, this man-made setup is very clean and highly isolated from environmental degrees of freedom. Moreover, to a large extent, the experimenter has dynamical control over the relevant system parameters: the interaction between atoms, the tunneling amplitude between lattice sites, and even the dimensionality of the lattice. These advantages render this system a unique platform for the simulation of quantum many-body dynamics for various lattice Hamiltonians as has been demonstrated in several experiments by now. The most significant step in recent times has arguably been the introduction of single-site detection of individual atoms in optical lattices. This technique, based on fluorescence microscopy, opens a new doorway for the study of quantum many-body states: the detection of the microscopic atom configuration. In this thesis, we theoretically explore the dynamics of ultracold atoms in optical lattices for various setups realized in present-day experiments. Our main focus lies on aspects that become experimentally accessible by (realistic extensions of) the novel single-site measurement technique. The first part deals with the expansion of initially confined atoms in a homogeneous lattice, which is one way to create atomic motion in experiments. We analyze the buildup of spatial correlations during the expansion of a finitely extended band insulating state in one dimension. The numerical simulation reveals the creation of remote spin-entangled fermions in the strongly interacting regime. We discuss the experimental observation of such spin-entangled pairs by means of a single-site measurement. Furthermore, we suggest studying the impact of observations on the expansion dynamics for the extreme case of a projective measurement in the spatial occupation

  16. Cardiac pacing in heart failure patients with left bundle branch block: impact of pacing site for optimizing left ventricular resynchronization.

    Science.gov (United States)

    Pappone, C; Rosanio, S; Oreto, G; Tocchi, M; Gulletta, S; Salvati, A; Dicandia, C; Santinelli, V; Mazzone, P; Veglia, F; Ding, J; Sallusti, L; Spinelli, J; Vicedomini, G

    2000-07-01

    Acute left ventricular pacing has been associated with hemodynamic improvement in patients with congestive heart failure and wide QRS complex. We hypothesized that pacing two left ventricular sites simultaneously would produce faster activation and better systolic function than single-site pacing. We selected 14 heart failure patients (NYHA functional class III or IV) in normal sinus rhythm with left bundle branch block and QRS > 150 ms. An 8F dual micromanometer catheter was placed in the aorta for measuring +dP/dt (mmHg/s), aortic pulse pressure (mmHg), and end-diastolic pressure (mmHg). Pacing leads were positioned via coronary veins at the posterior base and lateral wall. Patients were acutely paced VDD at the posterior base, lateral wall, and both sites (dual-site) with 5 atrioventricular delays (from 8 ms to PR -30 ms). Pacing sequences were executed in randomized order using a custom external computer (FlexStim, Guidant CRM). Dual-site pacing increased peak +dP/dt significantly more than posterior base and lateral wall pacing. Dual-site and posterior base pacing raised aortic pulse pressure significantly more than lateral wall pacing. Dual-site pacing shortened QRS duration by 22 %, whereas posterior base and lateral wall pacing increased it by 2 and 12%, respectively (p = 0.006). In heart failure patients with left bundle branch block, dual-site pacing improves systolic function more than single-site stimulation. Improved ventricular activation synchrony, expressed by paced QRS narrowing, may account for the additional benefit of dual- vs single-site pacing in enhancing contractility. This novel approach deserves consideration for future heart failure pacing studies.

  17. Multisite rainfall downscaling and disaggregation in a tropical urban area

    Science.gov (United States)

    Lu, Y.; Qin, X. S.

    2014-02-01

    A systematic downscaling-disaggregation study was conducted over Singapore Island, with an aim to generate high spatial and temporal resolution rainfall data under future climate-change conditions. The study consisted of two major components. The first part was to perform an inter-comparison of various alternatives of downscaling and disaggregation methods based on observed data. This included (i) single-site generalized linear model (GLM) plus K-nearest neighbor (KNN) (S-G-K) vs. multisite GLM (M-G) for spatial downscaling, (ii) HYETOS vs. KNN for single-site disaggregation, and (iii) KNN vs. MuDRain (Multivariate Rainfall Disaggregation tool) for multisite disaggregation. The results revealed that, for multisite downscaling, M-G performs better than S-G-K in covering the observed data with a lower RMSE value; for single-site disaggregation, KNN could better keep the basic statistics (i.e. standard deviation, lag-1 autocorrelation and probability of wet hour) than HYETOS; for multisite disaggregation, MuDRain outperformed KNN in fitting interstation correlations. In the second part of the study, an integrated downscaling-disaggregation framework based on M-G, KNN, and MuDRain was used to generate hourly rainfall at multiple sites. The results indicated that the downscaled and disaggregated rainfall data based on multiple ensembles from HadCM3 for the period from 1980 to 2010 could well cover the observed mean rainfall amount and extreme data, and also reasonably keep the spatial correlations both at daily and hourly timescales. The framework was also used to project future rainfall conditions under HadCM3 SRES A2 and B2 scenarios. It was indicated that the annual rainfall amount could reduce up to 5% at the end of this century, but the rainfall of wet season and extreme hourly rainfall could notably increase.

  18. Natural single amino acid polymorphism (F19Y) in human galectin-8: detection of structural alterations and increased growth-regulatory activity on tumor cells.

    Science.gov (United States)

    Ruiz, Federico M; Scholz, Barbara A; Buzamet, Eliza; Kopitz, Jürgen; André, Sabine; Menéndez, Margarita; Romero, Antonio; Solís, Dolores; Gabius, Hans-Joachim

    2014-03-01

    Natural amino acid substitution by single-site nucleotide polymorphism can become a valuable tool for structure-activity correlations, especially if evidence for association to disease parameters exists. Focusing on the F19Y change in human galectin-8, connected clinically to rheumatoid arthritis, we here initiate the study of consequences of a single-site substitution in the carbohydrate recognition domain of this family of cellular effectors. We apply a strategically combined set of structural and cell biological techniques for comparing properties of the wild-type and variant proteins. The overall hydrodynamic behavior of the full-length protein and of the separate N-domain is not noticeably altered, but displacements in the F0 β-strand of the β-sandwich fold in the N-domain are induced, as evidenced by protein crystallography. Analysis of thermal stability by circular dichroism spectroscopy revealed perceptible differences for the full-length proteins, pointing to an impact of the substitution beyond the N-domain. In addition, small differences in thermodynamic parameters of carbohydrate binding are detected. On the level of two types of tumor cells, characteristics of binding appeared rather similar. In further comparison of the influence on proliferation, the variant proved to be more active as growth regulator in the six tested lines of neuroblastoma, erythroleukemia and colon adenocarcinoma. The seemingly subtle structural change identified here thus has functional implications in vitro, encouraging further analysis in autoimmune regulation and, in a broad context, in work with other natural single-site variants, using the documented combined strategy. The atomic coordinates and structure factors (codes 4BMB, 4BME) have been deposited in the Protein Data Bank. © 2014 FEBS.

  19. Natural Variation in Grain Composition of Wheat and Related Cereals

    OpenAIRE

    Shewry, Peter R; Hawkesford, Malcolm J; Piironen, Vieno; Lampi, Anna-Maija; Gebruers, Kurt; Boros, Danuta; Andersson, Annica AM; Åman, Per; Rakszegi, Mariann; Bedo, Zoltan; Ward, Jane L

    2013-01-01

    The wheat grain comprises three groups of major components, starch, protein, and cell wall polysaccharides (dietary fiber), and a range of minor components that may confer benefits to human health. Detailed analyses of dietary fiber and other bioactive components were carried out under the EU FP6 HEALTHGRAIN program on 150 bread wheat lines grown on a single site, 50 lines of other wheat species and other cereals grown on the same site, and 23−26 bread wheat lines grown in six environments. P...

  20. Well-defined silica-supported zirconium–imido complexes mediated heterogeneous imine metathesis

    KAUST Repository

    Hamzaoui, Bilel

    2016-02-15

    Upon prolonged thermal exposure under vacuum, a well-defined single-site surface species [(≡Si-O-)Zr(NEt2)3] (1) evolves into an ethylimido complex [(≡Si-O-)Zr(=NEt)NEt2] (2). Reactions of 2 with an imine substrate result in imido/imine (=NRi, R: Et, Ph) exchange (metathesis) with the formation of [(≡Si-O-)Zr(=NPh)NEt2] (3). Compounds 2 and 3 effectively catalyze imine/imine cross-metathesis and are thus considered as the first heterogeneous catalysts active for imine metathesis. © The Royal Society of Chemistry 2016.

  1. Increase in D-tagatose production rate by site-directed mutagenesis of L-arabinose isomerase from Geobacillus thermodenitrificans.

    Science.gov (United States)

    Oh, Hyo-Jung; Kim, Hye-Jung; Oh, Deok-Kun

    2006-02-01

    Among single-site mutations of L-arabinose isomerase derived from Geobacillus thermodenitrificans, two mutants were produced having the lowest and highest activities of D-tagatose production. Site-directed mutagenesis at these sites showed that the aromatic ring at amino acid 164 and the size of amino acid 475 were important for D-tagatose production. Among double-site mutations, one mutant converted D-galactose into D-tagatose with a yield of 58% whereas the wild type gave 46% D-tagatose conversion after 300 min at 65 degrees C.

  2. Temperature and magnetic field dependence of magnetic correlations in the heavy fermion compound CeCu6

    International Nuclear Information System (INIS)

    Regnault, L.P.; Rossat-Mignod, J.; Jacoud, J.L.; Erkelens, W.A.C.; Rijksuniversiteit Leiden

    1988-01-01

    Inelastic neutron scattering experiments have been performed on the heavy fermion compound CeCu 6 at very low temperatures (T > 20 mK) and under magnetic fields up to 50 kOe. The analysis of the data shows that the magnetic scattering is the superposition of a single site contribution of Lorentzian type and of a broadened inelastic contribution associated with AF correlations. These correlations saturate below 1.5 - 2 K and are completely destroyed above 40 kOe

  3. Variational study of the pair hopping model

    International Nuclear Information System (INIS)

    Fazekas, P.

    1990-01-01

    We study the ground state of a Hamiltonian introduced by Kolb and Penson for modelling situations in which small electron pairs are formed. The Hamiltonian consists of a tight binding band term, and a term describing the nearest neighbour hopping of electron pairs. We give a Gutzwiller-type variational treatment, first with a single-parameter Ansatz treated in the single site Gutzwiller approximation, and then with more complicated trial wave functions, and an improved Gutzwiller approximation. The calculation yields a transition from a partially paired normal state, in which the spin susceptibility has a diminished value, into a fully paired state. (author). 16 refs, 2 figs

  4. Doubly stochastic Poisson process models for precipitation at fine time-scales

    Science.gov (United States)

    Ramesh, Nadarajah I.; Onof, Christian; Xie, Dichao

    2012-09-01

    This paper considers a class of stochastic point process models, based on doubly stochastic Poisson processes, in the modelling of rainfall. We examine the application of this class of models, a neglected alternative to the widely-known Poisson cluster models, in the analysis of fine time-scale rainfall intensity. These models are mainly used to analyse tipping-bucket raingauge data from a single site but an extension to multiple sites is illustrated which reveals the potential of this class of models to study the temporal and spatial variability of precipitation at fine time-scales.

  5. Madelung energy for random metallic alloys in the coherent potential approximation

    DEFF Research Database (Denmark)

    Korzhavyi, P. A.; Ruban, Andrei; Abrikosov, I. A.

    1995-01-01

    Within the conventional single-site coherent potential approximation (CPA) used to calculate thermodynamic properties of random alloys, the effect of charge transfer is neglected. We discuss a number of recent models based on the same mathematical form but with a different prefactor β which allow...... random alloy, and in this case the screened-CPA method (β=1/2) gives more correct results. It is suggested that a comparison with the results obtained by the Connolly-Williams method may be used to determine an optimal value for β depending on the alloy under consideration....

  6. Probing the putative active site of YjdL

    DEFF Research Database (Denmark)

    Jensen, Johanne Mørch; Ismat, Fouzia; Szakonyi, Gerda

    2012-01-01

    pocket that opens towards the extracellular space. The C-terminal side chain faces in the opposite direction into a sub pocket that faces the cytoplasm. These data indicated a stabilizing effect on a bulky N-terminal residue by an Ala281Phe variant and on the dipeptide backbone by Trp278...... with Glu388, a preliminary orientation model of a dipeptide in the YjdL cavity is presented. Single site mutations of particularly Ala281 and Trp278 support the presented orientation. A dipeptide bound in the cavity of YjdL appears to be oriented such that the N-terminal side chain protrudes into a sub...

  7. Fluctuating local field method probed for a description of small classical correlated lattices

    Science.gov (United States)

    Rubtsov, Alexey N.

    2018-05-01

    Thermal-equilibrated finite classical lattices are considered as a minimal model of the systems showing an interplay between low-energy collective fluctuations and single-site degrees of freedom. Standard local field approach, as well as classical limit of the bosonic DMFT method, do not provide a satisfactory description of Ising and Heisenberg small lattices subjected to an external polarizing field. We show that a dramatic improvement can be achieved within a simple approach, in which the local field appears to be a fluctuating quantity related to the low-energy degree(s) of freedom.

  8. Self-consistent cluster theory for systems with off-diagonal disorder

    International Nuclear Information System (INIS)

    Kaplan, T.; Leath, P.L.; Gray, L.J.; Diehl, H.W.

    1980-01-01

    A self-consistent cluster theory for elementary excitations in systems with diagonal, off-diagonal, and environmental disorder is presented. The theory is developed in augmented space where the configurational average over the disorder is replaced by a ground-state matrix element in a translationally invariant system. The analyticity of the resulting approximate Green's function is proved. Numerical results for the self-consistent single-site and pair approximations are presented for the vibrational and electronic properties of disordered linear chains with diagonal, off-diagonal, and environmental disorder

  9. Ocean energy

    International Nuclear Information System (INIS)

    2006-01-01

    This annual evaluation is a synthesis of works published in 2006. Comparisons are presented between the wind power performances and European Commission White Paper and Biomass action plan objectives. The sector covers the energy exploitation of all energy flows specifically supplied by the seas and oceans. At present, most efforts in both research and development and in experimental implementation are concentrated on tidal currents and wave power. 90% of today worldwide ocean energy production is represented by a single site: the Rance Tidal Power Plant. Ocean energies must face up two challenges: progress has to be made in finalizing and perfecting technologies and costs must be brought under control. (A.L.B.)

  10. Heisenberg magnetic chain with single-ion easy-plane anisotropy: Hubbard operators approach

    International Nuclear Information System (INIS)

    Spirin, D.V.; Fridman, Y.A.

    2003-01-01

    We investigate the gap in excitation spectrum of one-dimensional S=1 ferro- and antiferromagnets with easy-plane single-ion anisotropy. The self-consistent modification of Hubbard operators approach which enables to account single-site term exactly is used. For antiferromagnetic model we found Haldane phase that exists up to point D=4J (where D is anisotropy parameter, J is exchange coupling), while quadrupolar phase realizes at larger values of anisotropy. Our results specify those of Golinelli et al. (Phys. Rev. B. 45 (1992) 9798), where similar model was studied. Besides the method gives gap value closer to numerical estimations than usual spin-wave theories

  11. Measurement of specific [3H]-ouabain binding to different types of human leucocytes

    DEFF Research Database (Denmark)

    Boon, Arnold; Oh, V M; Taylor, John E.

    1984-01-01

    We have studied the specific binding of [3H]-ouabain to intact mononuclear leucocytes (82% lymphocytes) and polymorphonuclear leucocytes. In both types of cells [3H]-ouabain binding was saturable, confined to a single site of high affinity, slow to reach equilibrium, slow to reverse, temperature...... were expressed per square micron of cell surface area the difference between the two cell types was proportionately greater (83 and 186 sites per micron 2 respectively). We conclude that the [3H]-ouabain binding sites on mononuclear and polymorphonuclear leucocytes are similar in nature, but different...

  12. Intermetallic Alloys as CO Electroreduction Catalysts-Role of Isolated Active Sites

    DEFF Research Database (Denmark)

    Karamad, Mohammadreza; Tripkovic, Vladimir; Rossmeisl, Jan

    2014-01-01

    One of the main challenges associated with the electrochemical CO or CO2 reduction is poor selectivity toward energetically rich products. In order to promote selectivity toward hydrocarbons and alcohols, most notably, the hydrogen evolution reaction (HER) should be suppressed. To achieve this goal...... potentially selective intermetallic surfaces on which CO can be reduced to methanol at potentials comparable to or even slightly positive than those for CO/CO2 reduction to methane on Cu. Common features shared by most of the selective alloys are single TM sites. The role of single sites is to block parasitic...... HER and thereby promote CO reduction....

  13. Enhancing the photon-extraction efficiency of site-controlled quantum dots by deterministically fabricated microlenses

    Science.gov (United States)

    Kaganskiy, Arsenty; Fischbach, Sarah; Strittmatter, André; Rodt, Sven; Heindel, Tobias; Reitzenstein, Stephan

    2018-04-01

    We report on the realization of scalable single-photon sources (SPSs) based on single site-controlled quantum dots (SCQDs) and deterministically fabricated microlenses. The fabrication process comprises the buried-stressor growth technique complemented with low-temperature in-situ electron-beam lithography for the integration of SCQDs into microlens structures with high yield and high alignment accuracy. The microlens-approach leads to a broadband enhancement of the photon-extraction efficiency of up to (21 ± 2)% and a high suppression of multi-photon events with g (2)(τ = 0) SPSs which, can be applied in photonic quantum circuits and advanced quantum computation schemes.

  14. Dual-probe spectroscopic fingerprints of defects in graphene

    DEFF Research Database (Denmark)

    Settnes, Mikkel; Power, Stephen; Petersen, Dirch Hjorth

    2014-01-01

    (e.g., an extended graphene sheet). Applying this method, we study the transport anisotropies in pristine graphene sheets, and analyze the spectroscopic fingerprints arising from quantum interference around single-site defects, such as vacancies and adatoms. Furthermore, we demonstrate that the dual......-probe setup is a useful tool for characterizing the electronic transport properties of extended defects or designed nanostructures. In particular, we show that nanoscale perforations, or antidots, in a graphene sheet display Fano-type resonances with a strong dependence on the edge geometry of the perforation....

  15. Repeated detection of European bat lyssavirus type 2 in dead bats found at a single roost site in the UK.

    Science.gov (United States)

    Banyard, Ashley C; Johnson, N; Voller, K; Hicks, D; Nunez, A; Hartley, M; Fooks, A R

    2009-01-01

    In August 2007, European bat lyssavirus type 2 (EBLV-2) was isolated from a Daubenton's bat found at Stokesay Castle. In September 2008, another bat from the same vicinity of Stokesay Castle also tested positive for EBLV-2. This is the first occurrence of repeated detection of EBLV-2 from a single site. Here, we report the detection of low levels of viral RNA in various bat organs by qRT-PCR and detection of viral antigen by immunohistochemistry. We also report sequence data from both cases and compare data with those derived from other EBLV-2 isolations in the UK.

  16. Localisation in a Growth Model with Interaction

    Science.gov (United States)

    Costa, M.; Menshikov, M.; Shcherbakov, V.; Vachkovskaia, M.

    2018-05-01

    This paper concerns the long term behaviour of a growth model describing a random sequential allocation of particles on a finite cycle graph. The model can be regarded as a reinforced urn model with graph-based interaction. It is motivated by cooperative sequential adsorption, where adsorption rates at a site depend on the configuration of existing particles in the neighbourhood of that site. Our main result is that, with probability one, the growth process will eventually localise either at a single site, or at a pair of neighbouring sites.

  17. Eguchi-Kawai reduction with one flavor of adjoint Moebius fermion

    OpenAIRE

    Cunningham, William; Giedt, Joel

    2013-01-01

    We study the single site lattice gauge theory of SU(N) coupled to one Dirac flavor of fermion in the adjoint representation. We utilize M\\"obius fermions for this study, and accelerate the calculation with graphics processing units (GPUs). Our Monte Carlo simulations indicate that for sufficiently large inverse 't Hooft coupling b = 1/g^2 N, and for N \\leq 10 the distribution of traced Polyakov loops has "fingers" that extend from the origin. However, in the massless case the distribution of ...

  18. Mass anomalous dimension of Adjoint QCD at large N from twisted volume reduction

    CERN Document Server

    Pérez, Margarita García; Keegan, Liam; Okawa, Masanori

    2015-01-01

    In this work we consider the $SU(N)$ gauge theory with two Dirac fermions in the adjoint representation, in the limit of large $N$. In this limit the infinite-volume physics of this model can be studied by means of the corresponding twisted reduced model defined on a single site lattice. Making use of this strategy we study the reduced model for various values of $N$ up to 289. By analyzing the eigenvalue distribution of the adjoint Dirac operator we test the conformality of the theory and extract the corresponding mass anomalous dimension.

  19. Mass anomalous dimension of adjoint QCD at large N from twisted volume reduction

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, Margarita García [Instituto de Física Teórica UAM-CSIC, Nicolás Cabrera 13-15, Universidad Autónoma de Madrid,E-28049-Madrid (Spain); González-Arroyo, Antonio [Instituto de Física Teórica UAM-CSIC, Nicolás Cabrera 13-15, Universidad Autónoma de Madrid,E-28049-Madrid (Spain); Departamento de Física Teórica, C-XI, Universidad Autónoma de Madrid,E-28049-Madrid (Spain); Keegan, Liam [PH-TH, CERN,CH-1211 Geneva 23 (Switzerland); Okawa, Masanori [Graduate School of Science, Hiroshima University,Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Core of Research for the Energetic Universe, Hiroshima University,Higashi-Hiroshima, Hiroshima 739-8526 (Japan)

    2015-08-07

    In this work we consider the SU(N) gauge theory with two Dirac fermions in the adjoint representation, in the limit of large N. In this limit the infinite-volume physics of this model can be studied by means of the corresponding twisted reduced model defined on a single site lattice. Making use of this strategy we study the reduced model for various values of N up to 289. By analyzing the eigenvalue distribution of the adjoint Dirac operator we test the conformality of the theory and extract the corresponding mass anomalous dimension.

  20. Density functional theory study of elemental mercury adsorption on boron doped graphene surface decorated by transition metals

    Energy Technology Data Exchange (ETDEWEB)

    Jungsuttiwong, Siriporn, E-mail: siriporn.j@ubu.ac.th [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190 (Thailand); Wongnongwa, Yutthana [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190 (Thailand); Namuangruk, Supawadee [National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Klong Luang, Pathum Thani 12120 (Thailand); Kungwan, Nawee [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Promarak, Vinich [Department of Material Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210 (Thailand); Kunaseth, Manaschai, E-mail: manaschai@nanotec.or.th [National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Klong Luang, Pathum Thani 12120 (Thailand)

    2016-01-30

    Graphical abstract: Decoration of Pd{sub 4}-A (square planar) on B-doped graphene significantly promotes Hg{sup 0} adsorption, a single site of Pd{sub 4} cluster on BDG could strongly adsorb up to six Hg atoms. - Highlights: • Transition metal atom and cluster binds strongly on B-doped graphene surface. • Decoration of transition metal on B-doped graphene significantly promotes Hg{sup 0} adsorption. • Adsorption strength of Hg{sup 0} atom on metal decorated B-doped graphene: Pd > Pt > Ru > W > Cu. • One site decorated Pd4 cluster adsorbed Hg{sup 0} strongly up to six atoms.

  1. Height probabilities in the Abelian sandpile model on the generalized finite Bethe lattice

    Science.gov (United States)

    Chen, Haiyan; Zhang, Fuji

    2013-08-01

    In this paper, we study the sandpile model on the generalized finite Bethe lattice with a particular boundary condition. Using a combinatorial method, we give the exact expressions for all single-site probabilities and some two-site joint probabilities. As a by-product, we prove that the height probabilities of bulk vertices are all the same for the Bethe lattice with certain given boundary condition, which was found from numerical evidence by Grassberger and Manna ["Some more sandpiles," J. Phys. (France) 51, 1077-1098 (1990)], 10.1051/jphys:0199000510110107700 but without a proof.

  2. Floquet Engineering of Optical Solenoids and Quantized Charge Pumping along Tailored Paths in Two-Dimensional Chern Insulators

    Science.gov (United States)

    Wang, Botao; Ünal, F. Nur; Eckardt, André

    2018-06-01

    The insertion of a local magnetic flux, as the one created by a thin solenoid, plays an important role in gedanken experiments of quantum Hall physics. By combining Floquet engineering of artificial magnetic fields with the ability of single-site addressing in quantum gas microscopes, we propose a scheme for the realization of such local solenoid-type magnetic fields in optical lattices. We show that it can be employed to manipulate and probe elementary excitations of a topological Chern insulator. This includes quantized adiabatic charge pumping along tailored paths inside the bulk, as well as the controlled population of edge modes.

  3. REopt Screenings Catalyze Development of Hundreds of Megawatts of Renewable Energy for Federal Agencies

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-04-26

    The Federal Energy Management Program (FEMP) offers renewable energy project assistance to federal agencies, which often begins with a desktop screening to develop a prioritized portfolio of project opportunities. FEMP uses the National Renewable Energy Laboratory's REopt energy planning platform to screen potential renewable energy opportunities at a single site or across a range of sites. REopt helps organizations prioritize the most economi­cally and technically viable projects for further study and identifies the size and mix of technologies that meet the orga­nization's goals at minimum cost, along with the optimal operating strategies.

  4. Critique of one-stop siting in Washington: streamlining review without compromising effectiveness

    International Nuclear Information System (INIS)

    Granger, J.A.; Wise, K.R.

    1980-01-01

    The state of Washington adopted a one-stop power plant siting law in 1970 so that the regulatory elements could be coordinated into a single siting decision. Efficiency improves as duplications and inconsistencies disappear, but increasing lead times and higher costs persist in the state. An analysis of the legislation examines why certain statutory and regulatory provisions allow this to happen, pointing particularly at the review and approval process. Appropriate reforms include adequate funds and staff for the permit agency, early identification of issues, prehearing conferences, and explicit guidelines and standards. 114 references and footnotes

  5. Well-defined silica-supported zirconium–imido complexes mediated heterogeneous imine metathesis

    KAUST Repository

    Hamzaoui, Bilel; Pelletier, Jeremie; Abou-Hamad, Edy; Basset, Jean-Marie

    2016-01-01

    Upon prolonged thermal exposure under vacuum, a well-defined single-site surface species [(≡Si-O-)Zr(NEt2)3] (1) evolves into an ethylimido complex [(≡Si-O-)Zr(=NEt)NEt2] (2). Reactions of 2 with an imine substrate result in imido/imine (=NRi, R: Et, Ph) exchange (metathesis) with the formation of [(≡Si-O-)Zr(=NPh)NEt2] (3). Compounds 2 and 3 effectively catalyze imine/imine cross-metathesis and are thus considered as the first heterogeneous catalysts active for imine metathesis. © The Royal Society of Chemistry 2016.

  6. Overview of the essential tools

    International Nuclear Information System (INIS)

    Mount, R.P.

    1989-01-01

    The essential tools needed for the analysis of HEP experiments are software, networking, data handling, and CPU power. Leaving most software topics to other papers, this paper describes how we can use today's hardware effectively for HEP data analysis. It describes a new but viable model for HEP computing and data handling on a single site, and outlines the challenge of extending this environment to the wider university-based community. Finally it touches on the revolution in software design that may be triggered by the revolution in computing technology. (orig.)

  7. The phase diagrams of the site-diluted spin-1/2 Ising superlattice

    International Nuclear Information System (INIS)

    Saber, A.; Essaoudi, I.; Ainane, A.; Dujardin, F.; Saber, M.; Stebe, B.

    1998-08-01

    Using the effective field theory with a probability distribution technique that accounts for the single-site spin correlations, the critical behavior of a diluted spin-1/2 Ising superlattice consisting of two different ferromagnet materials is examined. The critical temperature of the system is studied as a function of the thickness of the constituents in a unit cell, the concentration of magnetic atoms, and the exchange interactions in each material. It is shown that the properties of the diluted system are different from those of the corresponding pure system. (author)

  8. Polarized-neutron study of spin dynamics in the Kondo insulator YbB12.

    Science.gov (United States)

    Nemkovski, K S; Mignot, J-M; Alekseev, P A; Ivanov, A S; Nefeodova, E V; Rybina, A V; Regnault, L-P; Iga, F; Takabatake, T

    2007-09-28

    Inelastic neutron scattering experiments have been performed on the archetype compound YbB(12), using neutron polarization analysis to separate the magnetic signal from the phonon background. With decreasing temperature, components characteristic for a single-site spin-fluctuation dynamics are suppressed, giving place to specific, strongly Q-dependent, low-energy excitations near the spin-gap edge. This crossover is discussed in terms of a simple crystal-field description of the incoherent high-temperature state and a predominantly local mechanism for the formation of the low-temperature singlet ground state.

  9. Synthesis of cobalt-containing mesoporous catalysts using the ultrasonic-assisted “pH-adjusting” method: Importance of cobalt species in styrene oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Baitao, E-mail: btli@scut.edu.cn; Zhu, Yanrun; Jin, Xiaojing

    2015-01-15

    Cobalt-containing SBA-15 and MCM-41 (Co-SBA-15 and Co-MCM-41) mesoporous catalysts were prepared via ultrasonic-assisted “pH-adjusting” technique in this study. Their physiochemical structures were comprehensively characterized and correlated with catalytic activity in oxidation of styrene. The nature of cobalt species depended on the type of mesoporous silica as well as pH values. The different catalytic performance between Co-SBA-15 and Co-MCM-41 catalysts originated from cobalt species. Cobalt species were homogenously incorporated into the siliceous framework of Co-SBA-15 in single-site Co(II) state, while Co{sub 3}O{sub 4} particles were loaded on Co-MCM-41 catalysts. The styrene oxidation tests showed that the single-site Co(II) state was more beneficial to the catalytic oxidation of styrene. The higher styrene conversion and benzaldehyde selectivity over Co-SBA-15 catalysts were mainly attributed to single-site Co(II) state incorporated into the framework of SBA-15. The highest conversion of styrene (34.7%) with benzaldehyde selectivity of 88.2% was obtained over Co-SBA-15 catalyst prepared at pH of 7.5, at the mole ratio of 1:1 (styrene to H{sub 2}O{sub 2}) at 70 °C. - Graphical abstract: Cobalt-containing mesoporous silica catalysts were developed via ultrasonic-assisted “pH-adjusting” technique. Compared with Co{sub 3}O{sub 4} in Co-MCM-41, the single-site Co(II) state in Co-SBA-15 was more efficient for the styrene oxidation. - Highlights: • Fast and cost-effective ultrasonic technique for preparing mesoporous materials. • Incorporation of Co via ultrasonic irradiation and “pH-adjusting”. • Physicochemical comparison between Co-SBA-15 and Co-MCM-41. • Correlation of styrene oxidation activity and catalyst structural property.

  10. Spatial-temporal analysis of wind power forecast errors for West-Coast Norway

    Energy Technology Data Exchange (ETDEWEB)

    Revheim, Paal Preede; Beyer, Hans Georg [Agder Univ. (UiA), Grimstad (Norway). Dept. of Engineering Sciences

    2012-07-01

    In this paper the spatial-temporal structure of forecast errors for wind power in West-Coast Norway is analyzed. Starting on the qualitative analysis of the forecast error reduction, with respect to single site data, for the lumped conditions of groups of sites the spatial and temporal correlations of the wind power forecast errors within and between the same groups are studied in detail. Based on this, time-series regression models to be used to analytically describe the error reduction are set up. The models give an expected reduction in forecast error between 48.4% and 49%. (orig.)

  11. State and local fiscal impacts associated with nuclear energy centers: some initial considerations

    International Nuclear Information System (INIS)

    Bjornstad, D.J.

    1976-04-01

    The concept of the nuclear energy center is designed to consolidate a number of electrical power reactors and/or related fuel cycle activities on a single site. Such a siting strategy would concentrate a great deal of economic activity in one area and, as a consequence, generate significant impacts on state and local governments by increasing tax bases and public service demands and by altering intergovernmental fiscal relations. This study was designed to place rough empirical measures on relevant impact variables and to highlight areas for which a need for further research was indicated.

  12. Developing a Model for Optimizing Inventory of Repairable Items at Single Operating Base

    OpenAIRE

    Le, Tin

    2016-01-01

    The use of EOQ model in inventory management is popular. However, EOQ models has many disadvantages, especially, when the model is applied to manage repairable items. In order to deal with high-cost and repairable items, Craig C. Sherbrooke introduced a model in his book “Optimal Inventory Modeling of Systems: Multi-Echelon Techniques”. The research focus is to implement and develop a program to execute the single-site in-ventory model for repairable items. The model helps to significantl...

  13. Monte Carlo simulation techniques for predicting annual power production

    International Nuclear Information System (INIS)

    Cross, J.P.; Bulandr, P.J.

    1991-01-01

    As the owner and operator of a number of small to mid-sized hydroelectric sites, STS HydroPower has been faced with the need to accurately predict anticipated hydroelectric revenues over a period of years. The typical approach to this problem has been to look at each site from a mathematical deterministic perspective and evaluate the annual production from historic streamflows. Average annual production is simply taken to be the area under the flow duration curve defined by the operating and design characteristics of the selected turbines. Minimum annual production is taken to be a historic dry year scenario and maximum production is viewed as power generated under the most ideal of conditions. Such an approach creates two problems. First, in viewing the characteristics of a single site, it does not take into account the probability of such an event occurring. Second, in viewing all sites in a single organization's portfolio together, it does not reflect the varying flow conditions at the different sites. This paper attempts to address the first of these two concerns, that being the creation of a simulation model utilizing the Monte Carlo method at a single site. The result of the analysis is a picture of the production at the site that is both a better representation of anticipated conditions and defined probabilistically

  14. Multiple-scattering formalism for correlated systems: A KKR-DMFT approach

    International Nuclear Information System (INIS)

    Minar, J.; Perlov, A.; Ebert, H.; Chioncel, L.; Katsnelson, M. I.; Lichtenstein, A.I.

    2005-01-01

    We present a charge and self-energy self-consistent computational scheme for correlated systems based on the Korringa-Kohn-Rostoker (KKR) multiple scattering theory with the many-body effects described by the means of dynamical mean field theory (DMFT). The corresponding local multiorbital and energy dependent self-energy is included into the set of radial differential equations for the single-site wave functions. The KKR Green's function is written in terms of the multiple scattering path operator, the later one being evaluated using the single-site solution for the t-matrix that in turn is determined by the wave functions. An appealing feature of this approach is that it allows to consider local quantum and disorder fluctuations on the same footing. Within the coherent potential approximation (CPA) the correlated atoms are placed into a combined effective medium determined by the DMFT self-consistency condition. Results of corresponding calculations for pure Fe, Ni, and Fe x Ni 1-x alloys are presented

  15. NANOSTRUCTURED METAL OXIDE CATALYSTS VIA BUILDING BLOCK SYNTHESES

    Energy Technology Data Exchange (ETDEWEB)

    Craig E. Barnes

    2013-03-05

    A broadly applicable methodology has been developed to prepare new single site catalysts on silica supports. This methodology requires of three critical components: a rigid building block that will be the main structural and compositional component of the support matrix; a family of linking reagents that will be used to insert active metals into the matrix as well as cross link building blocks into a three dimensional matrix; and a clean coupling reaction that will connect building blocks and linking agents together in a controlled fashion. The final piece of conceptual strategy at the center of this methodology involves dosing the building block with known amounts of linking agents so that the targeted connectivity of a linking center to surrounding building blocks is obtained. Achieving targeted connectivities around catalytically active metals in these building block matrices is a critical element of the strategy by which single site catalysts are obtained. This methodology has been demonstrated with a model system involving only silicon and then with two metal-containing systems (titanium and vanadium). The effect that connectivity has on the reactivity of atomically dispersed titanium sites in silica building block matrices has been investigated in the selective oxidation of phenols to benezoquinones. 2-connected titanium sites are found to be five times as active (i.e. initial turnover frequencies) than 4-connected titanium sites (i.e. framework titanium sites).

  16. Optimizing Geographic Allotment of Photovoltaic Capacity in a Distributed Generation Setting: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Urquhart, B.; Sengupta, M.; Keller, J.

    2012-09-01

    A multi-objective optimization was performed to allocate 2MW of PV among four candidate sites on the island of Lanai such that energy was maximized and variability in the form of ramp rates was minimized. This resulted in an optimal solution set which provides a range of geographic allotment alternatives for the fixed PV capacity. Within the optimal set, a tradeoff between energy produced and variability experienced was found, whereby a decrease in variability always necessitates a simultaneous decrease in energy. A design point within the optimal set was selected for study which decreased extreme ramp rates by over 50% while only decreasing annual energy generation by 3% over the maximum generation allocation. To quantify the allotment mix selected, a metric was developed, called the ramp ratio, which compares ramping magnitude when all capacity is allotted to a single location to the aggregate ramping magnitude in a distributed scenario. The ramp ratio quantifies simultaneously how much smoothing a distributed scenario would experience over single site allotment and how much a single site is being under-utilized for its ability to reduce aggregate variability. This paper creates a framework for use by cities and municipal utilities to reduce variability impacts while planning for high penetration of PV on the distribution grid.

  17. One-Tube-Only Standardized Site-Directed Mutagenesis: An Alternative Approach to Generate Amino Acid Substitution Collections.

    Directory of Open Access Journals (Sweden)

    Janire Mingo

    Full Text Available Site-directed mutagenesis (SDM is a powerful tool to create defined collections of protein variants for experimental and clinical purposes, but effectiveness is compromised when a large number of mutations is required. We present here a one-tube-only standardized SDM approach that generates comprehensive collections of amino acid substitution variants, including scanning- and single site-multiple mutations. The approach combines unified mutagenic primer design with the mixing of multiple distinct primer pairs and/or plasmid templates to increase the yield of a single inverse-PCR mutagenesis reaction. Also, a user-friendly program for automatic design of standardized primers for Ala-scanning mutagenesis is made available. Experimental results were compared with a modeling approach together with stochastic simulation data. For single site-multiple mutagenesis purposes and for simultaneous mutagenesis in different plasmid backgrounds, combination of primer sets and/or plasmid templates in a single reaction tube yielded the distinct mutations in a stochastic fashion. For scanning mutagenesis, we found that a combination of overlapping primer sets in a single PCR reaction allowed the yield of different individual mutations, although this yield did not necessarily follow a stochastic trend. Double mutants were generated when the overlap of primer pairs was below 60%. Our results illustrate that one-tube-only SDM effectively reduces the number of reactions required in large-scale mutagenesis strategies, facilitating the generation of comprehensive collections of protein variants suitable for functional analysis.

  18. PNN NGC 246: A Complex Photometric Behaviour That Requires Wet

    Directory of Open Access Journals (Sweden)

    Pérez J. M. González

    2003-03-01

    Full Text Available We present a study over three single-site campaigns to investigate the photometric behaviour of the PNN NGC 246. We observed this object in 2000 and 2001. The analysis of the light curves indicates complex and variable temporal spectra. Using wavelet analysis we have found evidences for changes on time scales of hours in the 2000 dataset. The temporal spectra obtained during 2001 are quite different from the results of the previous year. The modulations in the light curve are more noticeable and the temporal spectra present a higher number of modulation frequencies. One peculiar characteristic is the presence of a variable harmonic structure related to one of these modulation frequencies. This complex photometric behaviour may be explained by a more complicated unresolved combination of modulation frequencies, but more likely due to a combination of pulsations of the star plus modulations related to interaction with a close companion, maybe indicating a disc. However, these characteristics cannot be confirmed from single site observations. The complex and variable behaviour of NGC 246 needs the WET co-operation in order to completely resolve its light curve.

  19. Molecular single photon double K-shell ionization

    International Nuclear Information System (INIS)

    Penent, F.; Nakano, M.; Tashiro, M.; Grozdanov, T.P.; Žitnik, M.; Carniato, S.; Selles, P.; Andric, L.; Lablanquie, P.; Palaudoux, J.; Shigemasa, E.; Iwayama, H.; Hikosaka, Y.; Soejima, K.; Suzuki, I.H.; Kouchi, N.; Ito, K.

    2014-01-01

    We have studied single photon double K-shell ionization of small molecules (N 2 , CO, C 2 H 2n (n = 1–3), …) and the Auger decay of the resulting double core hole (DCH) molecular ions thanks to multi-electron coincidence spectroscopy using a magnetic bottle time-of-flight spectrometer. The relative cross-sections for single-site (K −2 ) and two-site (K −1 K −1 ) double K-shell ionization with respect to single K-shell (K −1 ) ionization have been measured that gives important information on the mechanisms of single photon double ionization. The spectroscopy of two-site (K −1 K −1 ) DCH states in the C 2 H 2n (n = 1–3) series shows important chemical shifts due to a strong dependence on the C-C bond length. In addition, the complete cascade Auger decay following single site (K −2 ) ionization has been obtained

  20. Theoretical evaluation of electromagnetic emissions from GSM900 mobile telephony base stations in the West Bank and Gaza Strip-Palestine

    International Nuclear Information System (INIS)

    Lahham, Adnan; Abu Alkbash, Jehad; ALMasri, Hussien

    2017-01-01

    Theoretical assessments of power density in far-field conditions were used to evaluate the levels of environmental electromagnetic frequencies from selected GSM900 macrocell base stations in the West Bank and Gaza Strip. Assessments were based on calculating the power densities using commercially available software (RF-Map from Telstra Research Laboratories-Australia). Calculations were carried out for single base stations with multi-antenna systems and also for multiple base stations with multi-antenna systems at 1.7 m above the ground level. More than 100 power density levels were calculated at different locations around the investigated base stations. These locations include areas accessible to the general public (schools, parks, residential areas, streets and areas around kindergartens). The maximum calculated electromagnetic emission level resulted from a single site was 0.413 μW cm -2 and found at Hizma town near Jerusalem. Average maximum power density from all single sites was 0.16 μW cm -2 . The results of all calculated power density levels in 100 locations distributed over the West Bank and Gaza were nearly normally distributed with a peak value of ∼0.01% of the International Commission on Non-Ionizing Radiation Protection's limit recommended for general public. Comparison between calculated and experimentally measured value of maximum power density from a base station showed that calculations overestimate the actual measured power density by ∼27%. (authors)

  1. Assessing FPAR Source and Parameter Optimization Scheme in Application of a Diagnostic Carbon Flux Model

    Energy Technology Data Exchange (ETDEWEB)

    Turner, D P; Ritts, W D; Wharton, S; Thomas, C; Monson, R; Black, T A

    2009-02-26

    The combination of satellite remote sensing and carbon cycle models provides an opportunity for regional to global scale monitoring of terrestrial gross primary production, ecosystem respiration, and net ecosystem production. FPAR (the fraction of photosynthetically active radiation absorbed by the plant canopy) is a critical input to diagnostic models, however little is known about the relative effectiveness of FPAR products from different satellite sensors nor about the sensitivity of flux estimates to different parameterization approaches. In this study, we used multiyear observations of carbon flux at four eddy covariance flux tower sites within the conifer biome to evaluate these factors. FPAR products from the MODIS and SeaWiFS sensors, and the effects of single site vs. cross-site parameter optimization were tested with the CFLUX model. The SeaWiFs FPAR product showed greater dynamic range across sites and resulted in slightly reduced flux estimation errors relative to the MODIS product when using cross-site optimization. With site-specific parameter optimization, the flux model was effective in capturing seasonal and interannual variation in the carbon fluxes at these sites. The cross-site prediction errors were lower when using parameters from a cross-site optimization compared to parameter sets from optimization at single sites. These results support the practice of multisite optimization within a biome for parameterization of diagnostic carbon flux models.

  2. Nonperturbative volume reduction of large-N QCD with adjoint fermions

    International Nuclear Information System (INIS)

    Bringoltz, Barak; Sharpe, Stephen R.

    2009-01-01

    We use nonperturbative lattice techniques to study the volume-reduced 'Eguchi-Kawai' version of four-dimensional large-N QCD with a single adjoint Dirac fermion. We explore the phase diagram of this single-site theory in the space of quark mass and gauge coupling using Wilson fermions for a number of colors in the range 8≤N≤15. Our evidence suggests that these values of N are large enough to determine the nature of the phase diagram for N→∞. We identify the region in the parameter space where the (Z N ) 4 center symmetry is intact. According to previous theoretical work using the orbifolding paradigm, and assuming that translation invariance is not spontaneously broken in the infinite-volume theory, in this region volume reduction holds: the single-site and infinite-volume theories become equivalent when N→∞. We find strong evidence that this region includes both light and heavy quarks (with masses that are at the cutoff scale), and our results are consistent with this region extending toward the continuum limit. We also compare the action density and the eigenvalue density of the overlap Dirac operator in the fundamental representation with those obtained in large-N pure-gauge theory.

  3. Bifunctional nanocrystalline MgO for chiral epoxy ketones via Claisen-Schmidt condensation-asymmetric epoxidation reactions.

    Science.gov (United States)

    Choudary, Boyapati M; Kantam, Mannepalli L; Ranganath, Kalluri V S; Mahendar, Koosam; Sreedhar, Bojja

    2004-03-24

    Design and development of a truly nanobifunctional heterogeneous catalyst for the Claisen-Schmidt condensation (CSC) of benzaldehydes with acetophenones to yield chalcones quantitatively followed by asymmetric epoxidation (AE) to afford chiral epoxy ketones with moderate to good yields and impressive ee's is described. The nanomagnesium oxide (aerogel prepared) NAP-MgO was found to be superior over the NA-MgO and CM-MgO in terms of activity and enantioselectivity as applicable in these reactions. An elegant strategy for heterogenization of homogeneous catalysts is presented here to evolve single-site chiral catalysts for AE by a successful transfer of molecular chemistry to surface metal-organic chemistry with the retention of activity, selectivity/enantioselectivity. Brønsted hydroxyls are established as sole contributors for the epoxidation reaction, while they add on to the CSC, which is largely driven by Lewis basic O2-sites. Strong hydrogen-bond interactions between the surface -OH on MgO and -OH groups of diethyl tartrate are found inducing enantioselectivity in the AE reaction. Thus, the nanocrystalline NAP-MgO with its defined shape, size, and accessible OH groups allows the chemisorption of TBHP, DET, and olefin on its surface to accomplish single-site chiral catalysts to provide optimum ee's in AE reactions.

  4. Radioactivity in the oceans

    International Nuclear Information System (INIS)

    Templeton, W.L.

    1979-01-01

    While the revised ''Definition and Recommendations'' of the International Atomic Energy Agency (IAEA) restricts the dumping of the radioactive wastes that exceed specified concentration/mass limits, the acceptance of the concept of applying the release rate limits as developed by the IAEA provides a rational basis for further considering the emplacement of radioactive wastes in seabed as an attractive and acceptable alternative to terrestrial geological repositories. The technical basis for the present radiological assessment is on release rate limits and not on dumping rates. However, to meet the present requirements of the London Convention, it is necessary to express to Definition in terms of the concentration in a single site and the assumed upper limit on mass dumping rate at a single site of 100,000 tons/year with the added proviso of release rate limits for the finite ocean volume of 10 17 m 3 . This results in the concentration limits of a) 1 Ci/ton for α-emitters but limited to 10 -1 Ci/ton 226 Ra and supported 210 Po; b) 10 2 Ci/ton for β/γ-emitters with half-lives of at least 0.5 yr (excluding 3 H) and the mixtures of β/γ-emitters of unknown half-lives; and c) 10 6 Ci/ton for 3 H and the β/γ-emitters with half-lives less than 0.5 yr. (Yamashita, S.)

  5. Lista anotada y clave para las ranas (género Eleutherodactylus chocoanas del Valle del Cauca, y apuntes sobre las especies de la Cordillera Occidental adyacente

    Directory of Open Access Journals (Sweden)

    Lynch John Douglas

    1999-11-01

    Full Text Available Twenty-three species of the genus Eleutherodactylus are reported fram 24 localities in the western lowlands of Valle del Cauca, Colombia, with notes on their identificacion and distributions. Up to 16 species have been taken from a single site. The cloud forest fauna of  Eleutherodactylus found on the Cordillera Occidental above the drainages of the Anchicayá, Cajambre, Calima, and Dagua rivers consists of 24 species with up to 18 species being found in a single site.Se da información sobre la identificación y las distribuciones de 23 especies del género Eleutherodactylus de 24 sitios de las tierras bajas del occidente del Valle del Cauca, Colombia. Hasta 16 especies fueron registradas del mismo sitio. La fauna de Eleutherodactylus de los bosques nublados de la Cordillera Occidental en los drenajes de los ríos Anchicayá, Cajambre, Calima, y Dagua consta de 24 especies, con hasta 18 encontradas en un mismo sitio.

  6. An approximate inversion method of geoelectrical sounding data using linear and bayesian statistical approaches. Examples of Tritrivakely volcanic lake and Mahitsy area (central part of Madagascar)

    International Nuclear Information System (INIS)

    Ranaivo Nomenjanahary, F.; Rakoto, H.; Ratsimbazafy, J.B.

    1994-08-01

    This paper is concerned with resistivity sounding measurements performed from single site (vertical sounding) or from several sites (profiles) within a bounded area. The objective is to present an accurate information about the study area and to estimate the likelihood of the produced quantitative models. The achievement of this objective obviously requires quite relevant data and processing methods. It also requires interpretation methods which should take into account the probable effect of an heterogeneous structure. In front of such difficulties, the interpretation of resistivity sounding data inevitably involves the use of inversion methods. We suggest starting the interpretation in simple situation (1-D approximation), and using the rough but correct model obtained as an a-priori model for any more refined interpretation. Related to this point of view, special attention should be paid for the inverse problem applied to the resistivity sounding data. This inverse problem is nonlinear, while linearity inherent in the functional response used to describe the physical experiment. Two different approaches are used to build an approximate but higher dimensional inversion of geoelectrical data: the linear approach and the bayesian statistical approach. Some illustrations of their application in resistivity sounding data acquired at Tritrivakely volcanic lake (single site) and at Mahitsy area (several sites) will be given. (author). 28 refs, 7 figs

  7. A comparison of single- and multi-site calibration and validation: a case study of SWAT in the Miyun Reservoir watershed, China

    Science.gov (United States)

    Bai, Jianwen; Shen, Zhenyao; Yan, Tiezhu

    2017-09-01

    An essential task in evaluating global water resource and pollution problems is to obtain the optimum set of parameters in hydrological models through calibration and validation. For a large-scale watershed, single-site calibration and validation may ignore spatial heterogeneity and may not meet the needs of the entire watershed. The goal of this study is to apply a multi-site calibration and validation of the Soil andWater Assessment Tool (SWAT), using the observed flow data at three monitoring sites within the Baihe watershed of the Miyun Reservoir watershed, China. Our results indicate that the multi-site calibration parameter values are more reasonable than those obtained from single-site calibrations. These results are mainly due to significant differences in the topographic factors over the large-scale area, human activities and climate variability. The multi-site method involves the division of the large watershed into smaller watersheds, and applying the calibrated parameters of the multi-site calibration to the entire watershed. It was anticipated that this case study could provide experience of multi-site calibration in a large-scale basin, and provide a good foundation for the simulation of other pollutants in followup work in the Miyun Reservoir watershed and other similar large areas.

  8. Lymph nodes tuberculosis: a retrospective study on clinical and therapeutic features.

    Science.gov (United States)

    Benjelloun, Amine; Darouassi, Youssef; Zakaria, Yasser; Bouchentouf, Rachid; Errami, Noureddine

    2015-01-01

    Lymph nodes tuberculosis represents 30 percent of extra pulmonary tuberculosis in Morocco. We report here the experience of the pulmonology unit of the Avicenne Military Hospital in Marrakech for a period of 4 years. Our study interested 30 patients (15 males and 15 females) with an average age of 29 years old (10 to 62 years old). Tuberculosis has interested a single site in 28 patients, the other two patients had multiple but unilateral involvement. For the single sites, locations were jugulo-carotidian (20 patients), supra-calvicular (2 patients), axillary (2 patients), sub-mandibular (2 patients), spinal (2 patients) and mediastinal (2 patients). For the multiple locations, the involvement was jugulo-carotidian, sub-mandibular, spinal and sub-clavicular for one patient; and jugulo-carotidian and sub-clavicular for the other. Diagnosis was made by surgical biopsy and histology for all the patients. A six-month anti-tuberculous treatment was given afterward, with relapses in two patients.

  9. Designing and implementing E-health Applications in the UK's National Health Service.

    Science.gov (United States)

    Bower, D Jane; Barry, Nessa; Reid, Margaret; Norrie, John

    2005-12-01

    Telemedicine/e-health applications have the potential to play an important role in Britain's National Health Service (NHS), including the NHS in Scotland. The Scottish Telemedicine Action Forum (STAF) was established by the Scottish Executive Department of Health in 1999 to take a range of applications, targeted on national priorities, into routine service. In the process it has provided insights into how advanced information and communication technologies (ICTs) can be moved from the research stage into routine service. In this article four of the projects are described and analysed focusing on the key issues that have emerged as critical for carrying projects successfully through to implementation in service as follows: 1. A multisite videoconferencing network linking 15 minor injury units to the main accident and emergency (A&E) centre. 2. A single-site neonatal intensive care "cotside" laptop system to assist communication between parents and clinical staff. 3. A single-site outpatient chronic disease management system. 4. A multisite software audit tool to support the care of cleft lip and palate patients from birth onward.

  10. A new framework for estimating return levels using regional frequency analysis

    Science.gov (United States)

    Winter, Hugo; Bernardara, Pietro; Clegg, Georgina

    2017-04-01

    We propose a new framework for incorporating more spatial and temporal information into the estimation of extreme return levels. Currently, most studies use extreme value models applied to data from a single site; an approach which is inefficient statistically and leads to return level estimates that are less physically realistic. We aim to highlight the benefits that could be obtained by using methodology based upon regional frequency analysis as opposed to classic single site extreme value analysis. This motivates a shift in thinking, which permits the evaluation of local and regional effects and makes use of the wide variety of data that are now available on high temporal and spatial resolutions. The recent winter storms over the UK during the winters of 2013-14 and 2015-16, which have caused wide-ranging disruption and damaged important infrastructure, provide the main motivation for the current work. One of the most impactful natural hazards is flooding, which is often initiated by extreme precipitation. In this presentation, we focus on extreme rainfall, but shall discuss other meteorological variables alongside potentially damaging hazard combinations. To understand the risks posed by extreme precipitation, we need reliable statistical models which can be used to estimate quantities such as the T-year return level, i.e. the level which is expected to be exceeded once every T-years. Extreme value theory provides the main collection of statistical models that can be used to estimate the risks posed by extreme precipitation events. Broadly, at a single site, a statistical model is fitted to exceedances of a high threshold and the model is used to extrapolate to levels beyond the range of the observed data. However, when we have data at many sites over a spatial domain, fitting a separate model for each separate site makes little sense and it would be better if we could incorporate all this information to improve the reliability of return level estimates. Here

  11. The concurrence of musculoskeletal pain and associated work-related factors: a cross sectional study

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Pereira Fernandes

    2016-07-01

    Full Text Available Abstract Background Several recent studies have described the presence of musculoskeletal complaints, presenting evidence that multisite musculoskeletal pain (MP is more often present than single-site musculoskeletal pain. However, less is known about determinants of this multimorbidity, particularly, concerning the role of occupational factors and, mainly, what determines single or multisite pain. This study described the associations between pain in different body sites and investigated related factors to MP in workers from Brazil. Methods A total of 1070 workers (228 women and 842 men, from urban cleaning services and from shoe manufacturers, participated in this cross sectional study (response 97 %. Interviewer-administered questionnaire included sociodemographic factors, physical and psychosocial work demands, leisure-time activities and musculoskeletal pain which was presence of pain in previous seven days, considering eight body sites and MP, the sum score of all painful sites, varying 0–8. A factor analysis was performed that captured the nine variables of physical exposure into two latent factors. Associations of pain between different body sites were assessed. Cox regression analyses, presenting the prevalence ratio (PR, showed the related factors to MP. Results In the previous seven days, 30 % of workers had MP. For all body sites, comorbidity ranged from 72 % to 91 %. Having pain in one body site is associated with pain in other site and the associations between proximal sites were stronger than between more distal sites. High exposure to manual material handling and awkward postures (PR = 1.5, 95 % CI 1.1–2.0, job strain (PR = 1.2, 95 % CI 1.0–1.6, and low social support (PR = 1.3, 95 % CI 1.0–1.7 and being woman (PR = 1.7, 95 % CI 1.3–2.3 were associated with MP. Risk factors for single–site pain and for subsequent musculoskeletal comorbidity were very similar, suggesting an additive effect of

  12. Establishment of a Site-Specific Tropospheric Model Based on Ground Meteorological Parameters over the China Region.

    Science.gov (United States)

    Zhou, Chongchong; Peng, Bibo; Li, Wei; Zhong, Shiming; Ou, Jikun; Chen, Runjing; Zhao, Xinglong

    2017-07-27

    China is a country of vast territory with complicated geographical environment and climate conditions. With the rapid progress of the Chinese BeiDou satellite navigation system (BDS); more accurate tropospheric models must be applied to improve the accuracy of navigation and positioning. Based on the formula of the Saastamoinen and Callahan models; this study develops two single-site tropospheric models (named SAAS_S and CH_S models) for the Chinese region using radiosonde data from 2005 to 2012. We assess the two single-site tropospheric models with radiosonde data for 2013 and zenith tropospheric delay (ZTD) data from four International GNSS Service (IGS) stations and compare them to the results of the Saastamoinen and Callahan models. The experimental results show that: the mean accuracy of the SAAS_S model (bias: 0.19 cm; RMS: 3.19 cm) at all radiosonde stations is superior to those of the Saastamoinen (bias: 0.62 cm; RMS: 3.62 cm) and CH_S (bias: -0.05 cm; RMS: 3.38 cm) models. In most Chinese regions; the RMS values of the SAAS_S and CH_S models are about 0.51~2.12 cm smaller than those of their corresponding source models. The SAAS_S model exhibits a clear improvement in the accuracy over the Saastamoinen model in low latitude regions. When the SAAS_S model is replaced by the SAAS model in the positioning of GNSS; the mean accuracy of vertical direction in the China region can be improved by 1.12~1.55 cm and the accuracy of vertical direction in low latitude areas can be improved by 1.33~7.63 cm. The residuals of the SAAS_S model are closer to a normal distribution compared to those of the Saastamoinen model. Single-site tropospheric models based on the short period of the most recent data (for example 2 years) can also achieve a satisfactory accuracy. The average performance of the SAAS_S model (bias: 0.83 cm; RMS: 3.24 cm) at four IGS stations is superior to that of the Saastamoinen (bias: -0.86 cm; RMS: 3.59 cm) and CH_S (bias: 0.45 cm; RMS: 3.38 cm

  13. Historical Datasets Support Genomic Selection Models for the Prediction of Cotton Fiber Quality Phenotypes Across Multiple Environments.

    Science.gov (United States)

    Gapare, Washington; Liu, Shiming; Conaty, Warren; Zhu, Qian-Hao; Gillespie, Vanessa; Llewellyn, Danny; Stiller, Warwick; Wilson, Iain

    2018-03-20

    Genomic selection (GS) has successfully been used in plant breeding to improve selection efficiency and reduce breeding time and cost. However, there has not been a study to evaluate GS prediction models that may be used for predicting cotton breeding lines across multiple environments. In this study, we evaluated the performance of Bayes Ridge Regression, BayesA, BayesB, BayesC and Reproducing Kernel Hilbert Spaces regression models. We then extended the single-site GS model to accommodate genotype × environment interaction (G×E) in order to assess the merits of multi- over single-environment models in a practical breeding and selection context in cotton, a crop for which this has not previously been evaluated. Our study was based on a population of 215 upland cotton ( Gossypium hirsutum ) breeding lines which were evaluated for fiber length and strength at multiple locations in Australia and genotyped with 13,330 single nucleotide polymorphic (SNP) markers. BayesB, which assumes unique variance for each marker and a proportion of markers to have large effects, while most other markers have zero effect, was the preferred model. GS accuracy for fiber length based on a single-site model varied across sites, ranging from 0.27 to 0.77 (mean = 0.38), while that of fiber strength ranged from 0.19 to 0.58 (mean = 0.35) using randomly selected sub-populations as the training population. Prediction accuracies from the M×E model were higher than those for single-site and across-site models, with an average accuracy of 0.71 and 0.59 for fiber length and strength, respectively. The use of the M×E model could therefore identify which breeding lines have effects that are stable across environments and which ones are responsible for G×E and so reduce the amount of phenotypic screening required in cotton breeding programs to identify adaptable genotypes. Copyright © 2018, G3: Genes, Genomes, Genetics.

  14. Simultaneous Reduction of CO 2 and Splitting of H 2 O by a Single Immobilized Cobalt Phthalocyanine Electrocatalyst

    KAUST Repository

    Morlanés, Natalia

    2016-04-12

    Perfluorinated cobalt phthalocyanine (CoFPc) immobilized on carbon electrodes was found to electrocatalyze the reduction of CO2 selectively to CO in an aqueous solution. The conversion of CO2 became apparent at -0.5 V vs RHE, and the Faradaic efficiency for the CO production reached as high as 93% at -0.8 V vs RHE. Highly stable electrolysis of CO2/H2O into CO/O2 was achieved for 12 h by applying the same catalyst as the cathode for CO2 reduction and the anode for water oxidation. This result indicates the highly robust nature of the CoFPc at wide range of potentials from -0.9 V to +2.2 V vs RHE, demonstrating the potential bipolar electrolytic system for CO2/H2O electrolysis, using the single-site molecular CoFPc-based electrocatalyst, which is simple, inexpensive, robust, and efficient. © 2016 American Chemical Society.

  15. Effects of leadership characteristics on pediatric registered nurses' job satisfaction.

    Science.gov (United States)

    Roberts-Turner, Reneé; Hinds, Pamela S; Nelson, John; Pryor, Juanda; Robinson, Nellie C; Wang, Jichuan

    2014-01-01

    Job satisfaction levels among registered nurses (RNs) influence RN recruitment, retention, turnover, and patient outcomes. Researchers examining the relationship between characteristics of nursing leadership and RN job satisfaction have treated RNs as a monolithic group with little research on the satisfaction of hospital-based pediatric RNs. This study assessed the relationship of transformational and transactional nursing leadership characteristics and RN job satisfaction reported by pediatric RNs. This single site study included 935 hospital-based pediatric RNs who completed validated survey items regarding nursing leadership and job satisfaction. A structural equation model (SEM) was applied to assess how autonomy (transformational leadership) and distributive justice (transactional leadership) influence RN job satisfaction, and how RN socio-demographic characteristics influence job satisfaction via autonomy and distributive justice. Findings revealed that both autonomy and distributive justice had significant positive effects on RN job satisfaction but the largest source of influence was autonomy.

  16. Automated phase picker and source location algorithm for local distances using a single three component seismic station

    International Nuclear Information System (INIS)

    Saari, J.

    1989-12-01

    The paper describes procedures for automatic location of local events by using single-site, three-component (3c) seismogram records. Epicentral distance is determined from the time difference between P- and S-onsets. For onset time estimates a special phase picker algorithm is introduced. Onset detection is accomplished by comparing short-term average with long-term average after multiplication of north, east and vertical components of recording. For epicentral distances up to 100 km, errors seldom exceed 5 km. The slowness vector, essentially the azimuth, is estimated independently by using the Christoffersson et al. (1988) 'polarization' technique, although a priori knowledge of the P-onset time gives the best results. Differences between 'true' and observed azimuths are generally less than 12 deg C. Practical examples are given by demonstrating the viability of the procedures for automated 3c seismogram analysis. The results obtained compare favourably with those achieved by a miniarray of three stations. (orig.)

  17. Ground-state properties of ordered, partially ordered, and random Cu-Au and Ni-Pt alloys

    DEFF Research Database (Denmark)

    Ruban, Andrei; Abrikosov, I. A.; Skriver, Hans Lomholt

    1995-01-01

    We have studied the ground-state properties of ordered, partially ordered, and random Cu-Au and Ni-Pt alloys at the stoichiometric 1/4, 1/2, and 3/4 compositions in the framework of the multisublattice single-site (SS) coherent potential approximation (CPA). Charge-transfer effects in the random ...... for the ordered alloys are in good agreement with experimental data. For all the alloys the calculated ordering energy and the equilibrium lattices parameters are found to be almost exact quadratic functions of the long-range-order parameter....... and the partially ordered alloys are included in the screened impurity model. The prefactor in the Madelung energy is determined by the requirement that the total energy obtained in direct SS CPA calculations should equal the total energy given by the Connolly-Williams expansion based on Green’s function...

  18. Natural variation in grain composition of wheat and related cereals.

    Science.gov (United States)

    Shewry, Peter R; Hawkesford, Malcolm J; Piironen, Vieno; Lampi, Ann-Maija; Gebruers, Kurt; Boros, Danuta; Andersson, Annica A M; Åman, Per; Rakszegi, Mariann; Bedo, Zoltan; Ward, Jane L

    2013-09-04

    The wheat grain comprises three groups of major components, starch, protein, and cell wall polysaccharides (dietary fiber), and a range of minor components that may confer benefits to human health. Detailed analyses of dietary fiber and other bioactive components were carried out under the EU FP6 HEALTHGRAIN program on 150 bread wheat lines grown on a single site, 50 lines of other wheat species and other cereals grown on the same site, and 23-26 bread wheat lines grown in six environments. Principal component analysis allowed the 150 bread wheat lines to be classified on the basis of differences in their contents of bioactive components and wheat species (bread, durum, spelt, emmer, and einkorn wheats) to be clearly separated from related cereals (barley, rye, and oats). Such multivariate analyses could be used to define substantial equivalence when novel (including transgenic) cereals are considered.

  19. A silica-supported double-decker silsesquioxane provides a second skin for the selective generation of bipodal surface organometallic complexes

    KAUST Repository

    Espinas, Jeff

    2012-11-12

    A well-defined silica-based material with a homogeneous nanolayer presenting identical pairs of vicinal silanols has been prepared by reaction of the surface organometallic species [≡SiOZr(CH 2CMe 3) 3], obtained on a silica dehydroxylated at 900 °C, with the double-decker-shaped silsesquioxane (OH) 2DD(OH) 2. The surface structure has been established using extensive NMR characterization ( 1H, 13C, 29Si, HETCOR, double-quantum, triple-quantum). Treatment with Zr(CH 2CMe 3) 4 leads to the first well-defined single-site bipodal grafted bis-neopentyl zirconium complex. © 2012 American Chemical Society.

  20. Solid-State NMR and DFT Studies on the Formation of Well-Defined Silica-Supported Tantallaaziridines: From Synthesis to Catalytic Application

    KAUST Repository

    Hamzaoui, Bilel

    2016-01-27

    Single-site, well-defined, silica-supported tantallaaziridine intermediates [≡Si-O-Ta(η2-NRCH2)(NMe2)2] [R=Me (2), Ph (3)] were prepared from silica-supported tetrakis(dimethylamido)tantalum [≡Si-O-Ta(NMe2)4] (1) and fully characterized by FTIR spectroscopy, elemental analysis, and 1H,13C HETCOR and DQ TQ solid-state (SS) NMR spectroscopy. The formation mechanism, by β-H abstraction, was investigated by SS NMR spectroscopy and supported by DFT calculations. The C-H activation of the dimethylamide ligand is favored for R=Ph. The results from catalytic testing in the hydroaminoalkylation of alkenes were consistent with the N-alkyl aryl amine substrates being more efficient than N-dialkyl amines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. A biogeographical perspective on species abundance distributions

    DEFF Research Database (Denmark)

    Matthews, Thomas J.; Borges, Paulo A. V.; de Azevedo, Eduardo Brito

    2017-01-01

    It has become increasingly recognized that multiple processes can generate similar shapes of species abundance distributions (SADs), with the result that the fit of a given SAD model cannot unambiguously provide evidence in support of a given theory or model. An alternative approach to comparing...... the fit of different SAD models to data from a single site is to collect abundance data from a variety of sites, and then build models to analyse how different SAD properties (e.g. form, skewness) vary with different predictor variables. Such a biogeographical approach to SAD research is potentially very...... revealing, yet there has been a general lack of interest in SADs in the biogeographical literature. In this Perspective, we address this issue by highlighting findings of recent analyses of SADs that we consider to be of intrinsic biogeographical interest. We use arthropod data drawn from the Azorean...

  2. Preparing and probing many-body correlated systems in a Quantum Gas Microscope by engineering arbitrary landscape potentials

    Science.gov (United States)

    Rispoli, Matthew; Lukin, Alexander; Ma, Ruichao; Preiss, Philipp; Tai, M. Eric; Islam, Rajibul; Greiner, Markus

    2015-05-01

    Ultracold atoms in optical lattices provide a versatile tool box for observing the emergence of strongly correlated physics in quantum systems. Dynamic control of optical potentials on the single-site level allows us to prepare and probe many-body quantum states through local Hamiltonian engineering. We achieve these high precision levels of optical control through spatial light modulation with a DMD (digital micro-mirror device). This allows for both arbitrary beam shaping and aberration compensation in our imaging system to produce high fidelity optical potentials. We use these techniques to control state initialization, Hamiltonian dynamics, and measurement in experiments investigating low-dimensional many-body physics - from one-dimensional correlated quantum walks to characterizing entanglement.

  3. Evolution and current challenges of laparoscopic cholecystectomy

    Directory of Open Access Journals (Sweden)

    XU Dahua.

    2013-03-01

    Full Text Available Since its introduction at the end of the 20th century, laparoscopic cholecystectomy has evolved into a safe and convenient minimally invasive surgical method, which is now the gold standard therapy for cholelithiasis worldwide. Physicians have continued to improve upon the procedure, creating methods that further minimize the related scarring and pain, such as the laproendoscopic single-site cholecystectomy and the gasless-lift laparoscopy. Additionally, the primary challenge of limited operative space in these procedures remains a key feature requiring improvement. In this review, the development and progression of laparoscopic cholecystectomy over the past 26 years is discussed, highlighting the current advantages and disadvantages that need to be addressed by practicing physicians to maximize the clinical value of this important therapy.

  4. Molecular Active Sites in Heterogeneous Ir-La/C-Catalyzed Carbonylation of Methanol to Acetates.

    Science.gov (United States)

    Kwak, Ja Hun; Dagle, Robert; Tustin, Gerald C; Zoeller, Joseph R; Allard, Lawrence F; Wang, Yong

    2014-02-06

    We report that when Ir and La halides are deposited on carbon, exposure to CO spontaneously generates a discrete molecular heterobimetallic structure, containing an Ir-La covalent bond that acts as a highly active, selective, and stable heterogeneous catalyst for the carbonylation of methanol to produce acetic acid. This catalyst exhibits a very high productivity of ∼1.5 mol acetyl/mol Ir·s with >99% selectivity to acetyl (acetic acid and methyl acetate) without detectable loss in activity or selectivity for more than 1 month of continuous operation. The enhanced activity can be mechanistically rationalized by the presence of La within the ligand sphere of the discrete molecular Ir-La heterobimetallic structure, which acts as a Lewis acid to accelerate the normally rate-limiting CO insertion in Ir-catalyzed carbonylation. Similar approaches may provide opportunities for attaining molecular (single site) behavior similar to homogeneous catalysis on heterogeneous surfaces for other industrial applications.

  5. Lattice-Assisted Spectroscopy: A Generalized Scanning Tunneling Microscope for Ultracold Atoms.

    Science.gov (United States)

    Kantian, A; Schollwöck, U; Giamarchi, T

    2015-10-16

    We propose a scheme to measure the frequency-resolved local particle and hole spectra of any optical lattice-confined system of correlated ultracold atoms that offers single-site addressing and imaging, which is now an experimental reality. Combining perturbation theory and time-dependent density matrix renormalization group simulations, we quantitatively test and validate this approach of lattice-assisted spectroscopy on several one-dimensional example systems, such as the superfluid and Mott insulator, with and without a parabolic trap, and finally on edge states of the bosonic Su-Schrieffer-Heeger model. We highlight extensions of our basic scheme to obtain an even wider variety of interesting and important frequency resolved spectra.

  6. Complex magnetic differentiation of cobalts in Na x CoO2 with 22 K Néel temperature

    Science.gov (United States)

    Mukhamedshin, I. R.; Gilmutdinov, I. F.; Salosin, M. A.; Alloul, H.

    2014-06-01

    Single crystals of sodium cobaltates Na x CoO2 with x ≈ 0.8 were grown by the floating zone technique. Using electrochemical Na de-intercalation method we reduced the sodium content in the as-grown crystals down to pure phase with 22 K Néel temperature and x ≈ 0.77. The 59Co NMR study in the paramagnetic state of the T N = 22 K phase permitted us to evidence that at least 6 Co sites are differentiated. They could be separated by their magnetic behavior into three types: a single site with cobalt close to non-magnetic Co3+, two sites with the most magnetic cobalts in the system, and the remaining three sites displaying an intermediate behavior. This unusual magnetic differentiation calls for more detailed NMR experiments on our well characterized samples.

  7. Cumulants of heat transfer across nonlinear quantum systems

    Science.gov (United States)

    Li, Huanan; Agarwalla, Bijay Kumar; Li, Baowen; Wang, Jian-Sheng

    2013-12-01

    We consider thermal conduction across a general nonlinear phononic junction. Based on two-time observation protocol and the nonequilibrium Green's function method, heat transfer in steady-state regimes is studied, and practical formulas for the calculation of the cumulant generating function are obtained. As an application, the general formalism is used to study anharmonic effects on fluctuation of steady-state heat transfer across a single-site junction with a quartic nonlinear on-site pinning potential. An explicit nonlinear modification to the cumulant generating function exact up to the first order is given, in which the Gallavotti-Cohen fluctuation symmetry is found still valid. Numerically a self-consistent procedure is introduced, which works well for strong nonlinearity.

  8. Full Counting Statistics for Interacting Fermions with Determinantal Quantum Monte Carlo Simulations.

    Science.gov (United States)

    Humeniuk, Stephan; Büchler, Hans Peter

    2017-12-08

    We present a method for computing the full probability distribution function of quadratic observables such as particle number or magnetization for the Fermi-Hubbard model within the framework of determinantal quantum Monte Carlo calculations. Especially in cold atom experiments with single-site resolution, such a full counting statistics can be obtained from repeated projective measurements. We demonstrate that the full counting statistics can provide important information on the size of preformed pairs. Furthermore, we compute the full counting statistics of the staggered magnetization in the repulsive Hubbard model at half filling and find excellent agreement with recent experimental results. We show that current experiments are capable of probing the difference between the Hubbard model and the limiting Heisenberg model.

  9. Investing in Threatened Species Conservation: Does Corruption Outweigh Purchasing Power?

    Science.gov (United States)

    Garnett, Stephen T.; Joseph, Liana N.; Watson, James E. M.; Zander, Kerstin K.

    2011-01-01

    In many sectors, freedom in capital flow has allowed optimization of investment returns through choosing sites that provide the best value for money. These returns, however, can be compromised in countries where corruption is prevalent. We assessed where the best value for money might be obtained for investment in threatened species that occur at a single site, when taking into account corruption. We found that the influence of corruption on potential investment decisions was outweighed by the likely value for money in terms of pricing parity. Nevertheless global conservation is likely to get best returns in terms of threatened species security by investing in “honest” countries than in corrupt ones, particularly those with a high cost of living. PMID:21818383

  10. Multi-layer multi-configuration time-dependent Hartree (ML-MCTDH) approach to the correlated exciton-vibrational dynamics in the FMO complex

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Jan; Kühn, Oliver, E-mail: oliver.kuehn@uni-rostock.de [Institut für Physik, Universität Rostock, Albert-Einstein-Str. 23-24, 18059 Rostock (Germany); Shibl, Mohamed F., E-mail: mfshibl@qu.edu.qa; Al-Marri, Mohammed J. [Gas Processing Center, College of Engineering, Qatar University, P.O. Box 2713, Doha (Qatar)

    2016-05-14

    The coupled quantum dynamics of excitonic and vibrational degrees of freedom is investigated for high-dimensional models of the Fenna-Matthews-Olson complex. This includes a seven- and an eight-site model with 518 and 592 harmonic vibrational modes, respectively. The coupling between local electronic transitions and vibrations is described within the Huang-Rhys model using parameters that are obtained by discretization of an experimental spectral density. Different pathways of excitation energy flow are analyzed in terms of the reduced one-exciton density matrix, focussing on the role of vibrational and vibronic excitations. Distinct features due to both competing time scales of vibrational and exciton motion and vibronically assisted transfer are observed. The question of the effect of initial state preparation is addressed by comparing the case of an instantaneous Franck-Condon excitation at a single site with that of a laser field excitation.

  11. Synthesis of Isomeric Phosphoubiquitin Chains Reveals that Phosphorylation Controls Deubiquitinase Activity and Specificity

    Directory of Open Access Journals (Sweden)

    Nicolas Huguenin-Dezot

    2016-07-01

    Full Text Available Ubiquitin is post-translationally modified by phosphorylation at several sites, but the consequences of these modifications are largely unknown. Here, we synthesize multi-milligram quantities of ubiquitin phosphorylated at serine 20, serine 57, and serine 65 via genetic code expansion. We use these phosphoubiquitins for the enzymatic assembly of 20 isomeric phosphoubiquitin dimers, with different sites of isopeptide linkage and/or phosphorylation. We discover that phosphorylation of serine 20 on ubiquitin converts UBE3C from a dual-specificity E3 ligase into a ligase that primarily synthesizes K48 chains. We profile the activity of 31 deubiquitinases on the isomeric phosphoubiquitin dimers in 837 reactions, and we discover that phosphorylation at distinct sites in ubiquitin can activate or repress cleavage of a particular linkage by deubiquitinases and that phosphorylation at a single site in ubiquitin can control the specificity of deubiquitinases for distinct ubiquitin linkages.

  12. Modulation of fronto-parietal connections during the rubber hand illusion

    DEFF Research Database (Denmark)

    Karabanov, Anke Ninija; Ritterband-Rosenbaum, Anina; Christensen, Mark Schram

    2017-01-01

    Accumulating evidence suggests that parieto-frontal connections play a role in adjusting body ownership during the Rubber Hand Illusion (RHI). Using a motor version of the rubber hand illusion paradigm, we applied single-site and dual-site transcranial magnetic stimulation (TMS) to investigate...... and during three RHI conditions: a) agency and ownership, b) agency but no ownership and c) neither agency nor ownership. Parietal-motor communication differed among experimental conditions. The induction of action ownership was associated with an inhibitory parietal-to-motor connectivity, which...... cortico-spinal and parietal-frontal connectivity during perceived rubber hand ownership. Healthy volunteers received a conditioning TMS pulse over left anterior intraparietal sulcus (aIPS) and a test TMS pulse over left primary motor cortex (M1). Motor Evoked Potentials (MEPs) were recorded at rest...

  13. Investing in threatened species conservation: does corruption outweigh purchasing power?

    Science.gov (United States)

    Garnett, Stephen T; Joseph, Liana N; Watson, James E M; Zander, Kerstin K

    2011-01-01

    In many sectors, freedom in capital flow has allowed optimization of investment returns through choosing sites that provide the best value for money. These returns, however, can be compromised in countries where corruption is prevalent. We assessed where the best value for money might be obtained for investment in threatened species that occur at a single site, when taking into account corruption. We found that the influence of corruption on potential investment decisions was outweighed by the likely value for money in terms of pricing parity. Nevertheless global conservation is likely to get best returns in terms of threatened species security by investing in "honest" countries than in corrupt ones, particularly those with a high cost of living.

  14. Characterization of polypropylene–polyethylene blends by temperature rising elution and crystallization analysis fractionation

    Science.gov (United States)

    del Hierro, Pilar

    2010-01-01

    The introduction of single-site catalysts in the polyolefins industry opens new routes to design resins with improved performance through multicatalyst-multireactor processes. Physical combination of various polyolefin types in a secondary extrusion process is also a common practice to achieve new products with improved properties. The new resins have complex structures, especially in terms of composition distribution, and their characterization is not always an easy task. Techniques like temperature rising elution fractionation (TREF) or crystallization analysis fractionation (CRYSTAF) are currently used to characterize the composition distribution of these resins. It has been shown that certain combinations of polyolefins may result in equivocal results if only TREF or CRYSTAF is used separately for their characterization. PMID:20730530

  15. Interoperating AliEn and ARC for a Distributed Tier1 in the Nordic Countries

    CERN Document Server

    Gros, Philippe; Lindemann, Jonas; Saiz, Pablo; Zarochentsev, Andrey

    2011-01-01

    To reach its large computing needs, the ALICE experiment at CERN has developed its own middleware called AliEn, centralised and relying on pilot jobs. One of its strength is the automatic installation of the required packages. The Nordic countries have offered a distributed Tier-1 centre for the CERN experiments, where the job management should be done with the NorduGrid middleware ARC. We have developed an interoperation module to allow to unify several computing sites using ARC, and make them look like a single site from the point of view of AliEn. A prototype has been completed and tested out of production. This talk will present implementation details of the system and its performance in tests.

  16. The Nuclear Criticality Information System: An update

    International Nuclear Information System (INIS)

    Koponen, B.L.

    1991-07-01

    The US Department of Energy's Nuclear Criticality Information System (NCIS) has served the criticality community for the past ten years with publications and with an online information system. NCIS provides a mean for widely distributed nuclear criticality specialists to communicate and work together instantly. Users of the system may receive assistance from all members of the NCIS community, which provides a much broader base of support than is available at any single site. When unified by NCIS, these diverse specialists provide a resource that has proven to be very useful in the safe handling of fissile material. NCIS also is a source of current nuclear criticality safety information; the rapid access of such up-to-date information on the handling of fissile materials outside of nuclear reactors is international in scope, extending beyond political and geographical boundaries

  17. Axin-mediated CKI phosphorylation of beta-catenin at Ser 45

    DEFF Research Database (Denmark)

    Amit, Sharon; Hatzubai, Ada; Birman, Yaara

    2002-01-01

    The Wnt pathway controls numerous developmental processes via the beta-catenin-TCF/LEF transcription complex. Deregulation of the pathway results in the aberrant accumulation of beta-catenin in the nucleus, often leading to cancer. Normally, cytoplasmic beta-catenin associates with APC and axin...... and is continuously phosphorylated by GSK-3beta, marking it for proteasomal degradation. Wnt signaling is considered to prevent GSK-3beta from phosphorylating beta-catenin, thus causing its stabilization. However, the Wnt mechanism of action has not been resolved. Here we study the regulation of beta......-catenin phosphorylation and degradation by the Wnt pathway. Using mass spectrometry and phosphopeptide-specific antibodies, we show that a complex of axin and casein kinase I (CKI) induces beta-catenin phosphorylation at a single site: serine 45 (S45). Immunopurified axin and recombinant CKI phosphorylate beta...

  18. Simulation of the oxidation pathway on Si(100) using high-resolution EELS

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, Conor [Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia (CNR-ISM), Rome (Italy); Dipartimento di Fisica, Universita di Roma ' ' Tor Vergata' ' , Roma (Italy); European Theoretical Spectroscopy Facility (ETSF), Roma (Italy); Caramella, Lucia; Onida, Giovanni [Dipartimento di Fisica, Universita degli Studi di Milano (Italy); European Theoretical Spectroscopy Facility (ETSF), Milano (Italy)

    2012-06-15

    We compute high-resolution electron energy loss spectra (HREELS) of possible structural motifs that form during the dynamic oxidation process on Si(100), including the important metastable precursor silanone and an adjacent-dimer bridge (ADB) structure that may seed oxide formation. Spectroscopic fingerprints of single site, silanone, and ''seed'' structures are identified and related to changes in the surface bandstructure of the clean surface. Incorporation of oxygen into the silicon lattice through adsorption and dissociation of water is also examined. Results are compared to available HREELS spectra and surface optical data, which are closely related. Our simulations confirm that HREELS offers complementary evidence to surface optical spectroscopy, and show that its high sensitivity allows it to distinguish between energetically and structurally similar oxidation models. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Mean field approximation for the kinetics of the selective catalytic reduction of NO by ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Santos, M.; Bodanese, J.P. [Centro de Ensino Sao Jose, Universidade do Vale do Itajai (Brazil); S. Grandi, B.C. da [Departamento de Fisica, Universidade Federal de Santa Catarina, Florianopolis (Brazil)

    2007-04-15

    In this work we study a catalytic reaction model among three monomers in order to understand the chemical kinetics of the selective catalytic reduction of nitrogen oxide by ammonia (4NO+4NH{sub 3}+O{sub 2}{yields}4N{sub 2}+6H{sub 2}O). Our model takes into account the formation of the intermediate species in the global scheme of the reaction. In order to determine the dynamical behaviour of the model we used single site approximation method. In this approach we have observed that, depending on the values of the control parameters, the model presents an active or an inactive phase. In fact, the dynamical phase diagram of the model exhibits a first order line separating these two phases. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Reduction in total plasma ghrelin levels following catecholamine depletion: relation to bulimic and depressive symptoms.

    Science.gov (United States)

    Homan, Philipp; Grob, Simona; Milos, Gabriella; Schnyder, Ulrich; Hasler, Gregor

    2013-09-01

    There is increasing preclinical and clinical evidence of the important role played by the gastric peptide hormone ghrelin in the pathogenesis of symptoms of depression and eating disorders. To investigate the role of ghrelin and its considered counterpart, peptide tyrosine tyrosine (PYY), in the development of bulimic and depressive symptoms induced by catecholamine depletion, we administered the tyrosine hydroxylase inhibitor alpha-methyl-paratyrosine (AMPT) in a randomized, double-blind, placebo-controlled crossover, single-site experimental trial to 29 healthy controls and 20 subjects with fully recovered bulimia nervosa (rBN). We found a decrease between preprandial and postprandial plasma ghrelin levels (psymptoms (psymptoms induced by catecholamine depletion. These findings suggest a relationship between catecholamines and ghrelin with depressive symptoms. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. A Concept for Support of Firefighter Frontline Communication

    Directory of Open Access Journals (Sweden)

    Tobias Dyrks

    2013-04-01

    Full Text Available In an indoor firefighter mission, coordination and communication support are of the utmost importance. We present our experience from over five years of research with current firefighter support technology. In contrast to some large scale emergency response research, our work is focused on the frontline interaction between teams of firefighters and the incident commander on a single site. In this paper we investigate the flaws in firefighter communication systems. Frequent technical failures and the high cognitive costs incurred by communicating impede coordination. We then extract a list of requirements for an assistant emergency management technology from expert interviews. Thirdly, we provide a system concept and explore challenges for building a novel firefighter support system based on our previous work. The system has three key features: robust ad-hoc network, telemetry and text messaging, as well as implicit interaction. The result would provide a complementary mode of communication in addition to the current trunked radio.

  2. Valley Hall Conductivity in Graphene: Effects of Higher-Order Scattering

    Science.gov (United States)

    Ando, Tsuneya

    2018-04-01

    The valley Hall conductivity, having opposite signs between the K and K' valleys, is calculated in monolayer and bilayer graphenes with nonzero gap in the presence of short-range scatterers within a single-site approximation. In the case of small disorder, the Hall conductivity is quantized into ±e2/2h and ±e2/h in the monolayer and bilayer graphene, respectively, in the gap region, while it is enhanced over the results in the absence of scatterers in the band region. With the increase in the strength of each impurity potential, large asymmetry between the conduction and valence band appears. For scatterers with attractive potential, the disorder parameter is effectively enhanced and reduced in the conduction and valence band, respectively. The behavior is opposite for repulsive scatterers. Effects of skew scattering causing asymmetry in the scattering direction remain small and do not play significant role.

  3. Energy and polarization dependence of resonant inelastic X-ray scattering in Nd2CuO4

    International Nuclear Information System (INIS)

    Hill, J.P.; Kao, C.C.; Haemaelaeinen, K.

    1998-01-01

    The authors report the energy and polarization dependence of resonant inelastic x-ray scattering from Nd 2 CuO 4 . An energy loss feature at ∼6 eV is observed in the vicinity of the Cu K-edge. Numerical calculations based on the Anderson impurity model identify this as a charge transfer excitation to the anti-bonding state. The incident polarization is shown to select the intermediate states participating in the resonance process. Resonances are observed at 8,990 eV and 9,000 eV with the incident polarization perpendicular and parallel to the CuO planes, respectively. In contrast to the single-site model calculations, no resonances are observed associated with the 1s3d 10 L intermediate states, suggesting non-local effects play a role

  4. Assessing screening criteria for the radiocarbon dating of bone mineral

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Ricardo, E-mail: ldv1452@gmail.com [Leibniz Labor for Isotopic and Radiometric Dating, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany); Huels, Matthias [Leibniz Labor for Isotopic and Radiometric Dating, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Nadeau, Marie-Josee; Grootes, Pieter M. [Leibniz Labor for Isotopic and Radiometric Dating, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany); Garbe-Schoenberg, C.-Dieter [Institute of Geosciences, Marine Climate Research and ICPMS Lab, Kiel University, Ludewig-Meyn-Str. 10, D-24118 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany); Hollund, Hege I. [Institute for Geo- and Bioarchaeology, The VU University, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands); Lotnyk, Andriy [Faculty of Engineering, Institute for Material Science, Synthesis and Real Structure, Kiel University, Kaiserstr. 2, D-24143 Kiel (Germany); Leibniz Institute of Surface Modification (IOM), Permoserstr. 15, D-04318 Leipzig (Germany); Kienle, Lorenz [Faculty of Engineering, Institute for Material Science, Synthesis and Real Structure, Kiel University, Kaiserstr. 2, D-24143 Kiel (Germany); Graduate School Human Development in Landscapes, Christian Albrecht University, Kiel (Germany)

    2013-01-15

    Radiocarbon dating of bone mineral (carbonate in the apatite lattice) has been the target of sporadic research for the last 40 years. Results obtained by different decontamination protocols have, however, failed to provide a consistent agreement with reference ages. In particular, quality criteria to assess bone mineral radiocarbon dating reliability are still lacking. Systematic research was undertaken to identify optimal preservation criteria for bone mineral in archeological bones. Six human long bones, originating from a single site, were radiocarbon-dated both for collagen and apatite, with the level of agreement between the dates providing an indication of exogenous carbon contamination. Several techniques (Histology, FTIR, TEM, LA-ICP-MS) were employed to determine the preservation status of each sample. Research results highlight the importance of a micro-scale approach in establishing bone preservation, in particular the use of trace element concentration profiles demonstrated its potential use as a viable sample selection criterion for bone carbonate radiocarbon dating.

  5. Superfluid/Bose-glass transition in one dimension

    Science.gov (United States)

    Ristivojevic, Zoran; Petković, Aleksandra; Le Doussal, Pierre; Giamarchi, Thierry

    2014-09-01

    We consider a one-dimensional system of interacting bosons in a random potential. At zero temperature, it can be either in the superfluid or in the insulating phase. We study the transition at weak disorder and moderate interaction. Using a systematic approach, we derive the renormalization group equations at two-loop order and discuss the phase diagram. We find the universal form of the correlation functions at the transitions and compute the logarithmic corrections to the main universal power-law behavior. In order to mimic large density fluctuations on a single site, we study a simplified model of disordered two-leg bosonic ladders with correlated disorder across the rung. Contrarily to the single-chain case, the latter system exhibits a transition between a superfluid and a localized phase where the exponents of the correlation functions at the transition do not take universal values.

  6. Black Adolescent Females’ Perceptions of Racial Discrimination When Accessing Reproductive and General Health Care

    Directory of Open Access Journals (Sweden)

    Valerie J. Lewis

    2016-09-01

    Full Text Available Adolescents, like adults, frequently experience discrimination, which can be particularly salient in the context of reproductive health care. We examined urban Black adolescent females’ perceived experiences of racial discrimination during reproductive health care encounters. Structured face-to-face interviews were conducted with female African American patients, from age 13 through 20, who obtained reproductive health care services at a single site. Twenty-four participants were enrolled. All were in or graduated from high school, with a mean age of 16.8 years. These young Black women reported infrequent race-based discrimination in the health care setting; however, many reported commonly experiencing discrimination in other places. An awareness of the discrimination that minority young women experience in non–health care settings can help providers demonstrate cultural humility when addressing such concerns with their patients. With this information, providers can provide anticipatory guidance and the tools necessary to navigate complex social systems.

  7. The Environmental Effects of Global Changes on Northeast Central Europe in the Case of Non-Modified Agricultural Management

    Directory of Open Access Journals (Sweden)

    H. Wiggering

    2008-06-01

    Full Text Available Climate impact scenarios for agriculture usually consider yield development, landscape water balance, nutrient dynamics or the endangerment of habitats separately. Scenario results are further limited by roughly discriminated land use types at low spatial resolution or they are restricted to single sites and isolated crops. Here, we exemplify a well data based comprehensive sensitivity analysis of a drought endangered agrarian region in Northeast Germany using a 2050 climate scenario. Coherently modelled results on water balance and yields indicate that agricultural production may persist, whereas wetlands and groundwater production will be negatively affected. The average percolation rate decreases from 143 mm a-1 to 12 mm a-1, and the average yield decline broken down by crops ranges from 4% for summer wheat to 14% for potatoes (main cereals: 5%.

  8. Dynamical barrier for the formation of solitary waves in discrete lattices

    International Nuclear Information System (INIS)

    Kevrekidis, P.G.; Espinola-Rocha, J.A.; Drossinos, Y.; Stefanov, A.

    2008-01-01

    We consider the problem of the existence of a dynamical barrier of 'mass' that needs to be excited on a lattice site to lead to the formation and subsequent persistence of localized modes for a nonlinear Schroedinger lattice. We contrast the existence of a dynamical barrier with its absence in the static theory of localized modes in one spatial dimension. We suggest an energetic criterion that provides a sufficient, but not necessary, condition on the amplitude of a single-site initial condition required to form a solitary wave. We show that this effect is not one-dimensional by considering its two-dimensional analog. The existence of a sufficient condition for the excitation of localized modes in the non-integrable, discrete, nonlinear Schroedinger equation is compared to the dynamics of excitations in the integrable, both discrete and continuum, version of the nonlinear Schroedinger equation

  9. Dynamical barrier for the formation of solitary waves in discrete lattices

    Energy Technology Data Exchange (ETDEWEB)

    Kevrekidis, P.G. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003 (United States)], E-mail: kevrekid@math.umass.edu; Espinola-Rocha, J.A. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003 (United States); Drossinos, Y. [European Commission, Joint Research Centre, I-21020 Ispra (Vatican City State, Holy See,) (Italy); School of Mechanical and Systems Engineering, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU (United Kingdom); Stefanov, A. [Department of Mathematics, University of Kansas, 1460 Jayhawk Blvd., Lawrence, KS 66045-7523 (United States)

    2008-03-24

    We consider the problem of the existence of a dynamical barrier of 'mass' that needs to be excited on a lattice site to lead to the formation and subsequent persistence of localized modes for a nonlinear Schroedinger lattice. We contrast the existence of a dynamical barrier with its absence in the static theory of localized modes in one spatial dimension. We suggest an energetic criterion that provides a sufficient, but not necessary, condition on the amplitude of a single-site initial condition required to form a solitary wave. We show that this effect is not one-dimensional by considering its two-dimensional analog. The existence of a sufficient condition for the excitation of localized modes in the non-integrable, discrete, nonlinear Schroedinger equation is compared to the dynamics of excitations in the integrable, both discrete and continuum, version of the nonlinear Schroedinger equation.

  10. ESR dating: is it still an 'experimental' technique?

    International Nuclear Information System (INIS)

    Skinner, A.R.

    2000-01-01

    Nearly 25 years ago, Motoji Ikeya demonstrated the potential of ESR dating. From a single substance (stalagmitic carbonate) and a single site (Akiyoshi Cavern), the field has grown to include materials from all over the world and time periods from a few thousand years ago to several million years ago. A vigorous program of instrumentation development has increased the precision of measurements as well as opening up new ways of collecting and interpreting spectra. Yet there are still references to ESR dating as an 'experimental' technique, one which cannot be trusted to produce dates that are accurate or precise. This paper discusses areas for which this is true and suggests what should be done to convince skeptics. Other areas for which the evidence suggests that ESR is at least as reliable as 'standard' methods will also be covered

  11. Integration of vectors by homologous recombination in the plant pathogen Glomerella cingulata.

    Science.gov (United States)

    Rikkerink, E H; Solon, S L; Crowhurst, R N; Templeton, M D

    1994-03-01

    An homologous transformation system has been developed for the plant pathogenic fungus Glomerella cingulata (Colletotrichum gloeosporioides). A transformation vector containing the G. cingulata gpdA promoter fused to the hygromycin phosphotransferase gene was constructed. Southern analyses indicated that this vector integrated at single sites in most transformants. A novel method of PCR amplification across the recombination junction point indicated that the integration event occurred by homologous recombination in more than 95% of the transformants. Deletion studies demonstrated that 505 bp (the minimum length of homologous promoter DNA analysed which was still capable of promoter function) was sufficient to target integration events. Homologous integration of the vector resulted in duplication of the gdpA promoter region. When transformants were grown without selective pressure, a high incidence of vector excision by recombination between the duplicated regions was evident. The significance of these recombination characteristics is discussed with reference to the feasibility of performing gene disruption experiments.

  12. Opioid binding site in EL-4 thymoma cell line

    International Nuclear Information System (INIS)

    Fiorica, E.; Spector, S.

    1988-01-01

    Using EL-4 thymoma cell-line we found a binding site similar to the k opioid receptor of the nervous system. The Scatchard analysis of the binding of [ 3 H] bremazocine indicated a single site with a K/sub D/ = 60 +/- 17 nM and Bmax = 2.7 +/- 0.8 pmols/10 6 cells. To characterize this binding site, competition studies were performed using selective compounds for the various opioid receptors. The k agonist U-50,488H was the most potent displacer of [ 3 H] bremazocine with an IC 50 value = 0.57μM. The two steroisomers levorphanol and dextrorphan showed the same affinity for this site. While morphine, [D-Pen 2 , D-Pen 5 ] enkephalin and β-endorphin failed to displace, except at very high concentrations, codeine demonstrated a IC 50 = 60μM, that was similar to naloxone. 32 references, 3 figures, 2 tables

  13. Censored rainfall modelling for estimation of fine-scale extremes

    Science.gov (United States)

    Cross, David; Onof, Christian; Winter, Hugo; Bernardara, Pietro

    2018-01-01

    Reliable estimation of rainfall extremes is essential for drainage system design, flood mitigation, and risk quantification. However, traditional techniques lack physical realism and extrapolation can be highly uncertain. In this study, we improve the physical basis for short-duration extreme rainfall estimation by simulating the heavy portion of the rainfall record mechanistically using the Bartlett-Lewis rectangular pulse (BLRP) model. Mechanistic rainfall models have had a tendency to underestimate rainfall extremes at fine temporal scales. Despite this, the simple process representation of rectangular pulse models is appealing in the context of extreme rainfall estimation because it emulates the known phenomenology of rainfall generation. A censored approach to Bartlett-Lewis model calibration is proposed and performed for single-site rainfall from two gauges in the UK and Germany. Extreme rainfall estimation is performed for each gauge at the 5, 15, and 60 min resolutions, and considerations for censor selection discussed.

  14. The transverse spin-1 Ising model with random interactions

    Energy Technology Data Exchange (ETDEWEB)

    Bouziane, Touria [Department of Physics, Faculty of Sciences, University of Moulay Ismail, B.P. 11201 Meknes (Morocco)], E-mail: touria582004@yahoo.fr; Saber, Mohammed [Department of Physics, Faculty of Sciences, University of Moulay Ismail, B.P. 11201 Meknes (Morocco); Dpto. Fisica Aplicada I, EUPDS (EUPDS), Plaza Europa, 1, San Sebastian 20018 (Spain)

    2009-01-15

    The phase diagrams of the transverse spin-1 Ising model with random interactions are investigated using a new technique in the effective field theory that employs a probability distribution within the framework of the single-site cluster theory based on the use of exact Ising spin identities. A model is adopted in which the nearest-neighbor exchange couplings are independent random variables distributed according to the law P(J{sub ij})=p{delta}(J{sub ij}-J)+(1-p){delta}(J{sub ij}-{alpha}J). General formulae, applicable to lattices with coordination number N, are given. Numerical results are presented for a simple cubic lattice. The possible reentrant phenomenon displayed by the system due to the competitive effects between exchange interactions occurs for the appropriate range of the parameter {alpha}.

  15. Advanced Energy Saving and its Applications in Industry

    CERN Document Server

    Matsuda, Kazuo; Fushimi, Chihiro; Tsutsumi, Atsushi; Kishimoto, Akira

    2013-01-01

    The conventional approach for energy saving in a process system is to maximize heat recovery without changing any process conditions by using pinch technology. “Self-heat recuperation technology” was developed to achieve further energy saving in the process system by eliminating the necessity for any external heat input, such as firing or imported steam. Advanced Energy Saving and its Applications in Industry introduces the concept of self-heat recuperation and the application of such technology to a wide range of processes from heavy chemical complexes to other processes such as drying and gas separation processes, which require heating and cooling during operation.   Conventional energy saving items in a utility system are applied and implemented based on a single site approach, however, when looking at heavy chemical complexes, it was apparent that the low-grade heat discharged as waste from a refinery could also be used in an adjacent petrochemical plant. There could therefore be a large energy savin...

  16. Buried Volume Analysis for Propene Polymerization Catalysis Promoted by Group 4 Metals: a Tool for Molecular Mass Prediction

    KAUST Repository

    Falivene, Laura; Cavallo, Luigi; Talarico, Giovanni

    2015-01-01

    A comparison of the steric properties of homogeneous single site catalysts for propene polymerization using the percentage of buried volume (%VBur) as molecular descriptor is reported. The %VBur calculated on the neutral precursors of the active species seems to be a reliable tool to explain several experimental data related to the propene insertion and to the monomer chain transfer. Interestingly, a linear correlation between the buried volume calculated for a large set of neutral precursors and the energetic difference between propagation and termination steps calculated by DFT methods is found for Group 4 metal catalysts. The “master curves” derived for Ti, Zr and Hf confirm not only that the %VBur is an appropriate molecular descriptor for the systems considered but also that it could be used as tool for a large computational screening of new ligands.

  17. Inhibition by Siomycin and Thiostrepton of Both Aminoacyl-tRNA and Factor G Binding to Ribosomes

    Science.gov (United States)

    Ll, Juan Modole; Cabrer, Bartolomé; Parmeggiani, Andrea; Azquez, David V

    1971-01-01

    Siomycin, a peptide antibiotic that interacts with the 50S ribosomal subunit and inhibits binding of factor G, is shown also to inhibit binding of aminoacyl-tRNA; however, it does not impair binding of fMet-tRNA and completion of the initiation complex. Moreover, unlike other inhibitors of aminoacyl-tRNA binding (tetracycline, sparsomycin, and streptogramin A), siomycin completely abolishes the GTPase activity associated with the binding of aminoacyl-tRNA catalyzed by factor Tu. A single-site interaction of siomycin appears to be responsible for its effect on both the binding of the aminoacyl-tRNA-Tu-GTP complex and that of factor G. PMID:4331558

  18. Noise-induced hearing loss - An examination of the methods of assessment in a cross-sectional study of 87 industrial workers.

    Science.gov (United States)

    Das, S; Mulheran, M; Brewster, M; Banerjee, A R

    2018-04-01

    The surveillance of noise-induced hearing loss (NIHL) according to the Health and Safety Executive (HSE) differs from the medico-legal criteria used to assess NIHL. Our study compares the two systems and proposes a novel method of simplifying the medico-legal criteria and applying it to ascertain noise-induced hearing loss. The anonymised audiograms of a group of 87 industrial workers from a single site were analysed with both methods. The comparison showed approximately one-third of the workers assessed in this study had their noise-induced hearing loss underestimated by the HSE criteria. The majority of these individuals were over 40 years of age. The HSE criteria for noise-induced hearing loss need review and re-alignment with the medico-legal criteria to address the discrepancy between the two systems. © 2017 John Wiley & Sons Ltd.

  19. Electron Scattering in Solid Matter A Theoretical and Computational Treatise

    CERN Document Server

    Zabloudil, Jan; Szunyogh, Laszlo

    2005-01-01

    Addressing graduate students and researchers, this book gives a very detailed theoretical and computational description of multiple scattering in solid matter. Particular emphasis is placed on solids with reduced dimensions, on full potential approaches and on relativistic treatments. For the first time approaches such as the Screened Korringa-Kohn-Rostoker method that have emerged during the last 5 – 10 years are reviewed, considering all formal steps such as single-site scattering, structure constants and screening transformations, and also the numerical point of view. Furthermore, a very general approach is presented for solving the Poisson equation, needed within density functional theory in order to achieve self-consistency. Going beyond ordered matter and translationally invariant systems, special chapters are devoted to the Coherent Potential Approximation and to the Embedded Cluster Method, used, for example, for describing nanostructured matter in real space. In a final chapter, physical properties...

  20. Orbital effect of the magnetic field in dynamical mean-field theory

    Science.gov (United States)

    Acheche, S.; Arsenault, L.-F.; Tremblay, A.-M. S.

    2017-12-01

    The availability of large magnetic fields at international facilities and of simulated magnetic fields that can reach the flux-quantum-per-unit-area level in cold atoms calls for systematic studies of orbital effects of the magnetic field on the self-energy of interacting systems. Here we demonstrate theoretically that orbital effects of magnetic fields can be treated within single-site dynamical mean-field theory with a translationally invariant quantum impurity problem. As an example, we study the one-band Hubbard model on the square lattice using iterated perturbation theory as an impurity solver. We recover the expected quantum oscillations in the scattering rate, and we show that the magnetic fields allow the interaction-induced effective mass to be measured through the single-particle density of states accessible in tunneling experiments. The orbital effect of magnetic fields on scattering becomes particularly important in the Hofstadter butterfly regime.

  1. Application of objective clinical human reliability analysis (OCHRA) in assessment of technical performance in laparoscopic rectal cancer surgery.

    Science.gov (United States)

    Foster, J D; Miskovic, D; Allison, A S; Conti, J A; Ockrim, J; Cooper, E J; Hanna, G B; Francis, N K

    2016-06-01

    Laparoscopic rectal resection is technically challenging, with outcomes dependent upon technical performance. No robust objective assessment tool exists for laparoscopic rectal resection surgery. This study aimed to investigate the application of the objective clinical human reliability analysis (OCHRA) technique for assessing technical performance of laparoscopic rectal surgery and explore the validity and reliability of this technique. Laparoscopic rectal cancer resection operations were described in the format of a hierarchical task analysis. Potential technical errors were defined. The OCHRA technique was used to identify technical errors enacted in videos of twenty consecutive laparoscopic rectal cancer resection operations from a single site. The procedural task, spatial location, and circumstances of all identified errors were logged. Clinical validity was assessed through correlation with clinical outcomes; reliability was assessed by test-retest. A total of 335 execution errors identified, with a median 15 per operation. More errors were observed during pelvic tasks compared with abdominal tasks (p technical performance of laparoscopic rectal surgery.

  2. Pediatric morphea (localized scleroderma): review of 136 patients.

    Science.gov (United States)

    Christen-Zaech, Stéphanie; Hakim, Miriam D; Afsar, F Sule; Paller, Amy S

    2008-09-01

    Morphea is an autoimmune inflammatory sclerosing disorder that may cause permanent functional disability and disfigurement. We sought to determine the clinical features of morphea in a large pediatric cohort. We conducted a retrospective chart review of 136 pediatric patients with morphea from one center, 1989 to 2006. Most children showed linear morphea, with a disproportionately high number of Caucasian and female patients. Two patients with rapidly progressing generalized or extensive linear morphea and arthralgias developed restrictive pulmonary disease. Initial oral corticosteroid treatment and long-term methotrexate administration stabilized and/or led to disease improvement in most patients with aggressive disease. Retrospective analysis, relatively small sample size, and risk of a selected referral population to the single site are limitations. These data suggest an increased prevalence of morphea in Caucasian girls, and support methotrexate as treatment for problematic forms. Visceral manifestations rarely occur; the presence of progressive problematic cutaneous disease and arthralgias should trigger closer patient monitoring.

  3. Mixed spin Ising model with four-spin interaction and random crystal field

    International Nuclear Information System (INIS)

    Benayad, N.; Ghliyem, M.

    2012-01-01

    The effects of fluctuations of the crystal field on the phase diagram of the mixed spin-1/2 and spin-1 Ising model with four-spin interactions are investigated within the finite cluster approximation based on a single-site cluster theory. The state equations are derived for the two-dimensional square lattice. It has been found that the system exhibits a variety of interesting features resulting from the fluctuation of the crystal field interactions. In particular, for low mean value D of the crystal field, the critical temperature is not very sensitive to fluctuations and all transitions are of second order for any value of the four-spin interactions. But for relatively high D, the transition temperature depends on the fluctuation of the crystal field, and the system undergoes tricritical behaviour for any strength of the four-spin interactions. We have also found that the model may exhibit reentrance for appropriate values of the system parameters.

  4. Phase diagrams of a spin-1 Ising superlattice with alternating transverse field

    International Nuclear Information System (INIS)

    Saber, A.; Ez-Zahraouy, H.; Lo Russo, S.; Mattei, G.; Ainane, A.

    2003-01-01

    The effects of alternating transverse fields Ω a and Ω b on the critical behavior of an alternating spin-1 Ising superlattice are studied within an effective field theory with a probability distribution technique that accounts for the single-site spin correlation. Critical temperatures are calculated as a function of the thickness of the superlattice and the strength of the transverse field. Depending on the values of the transverse fields Ω a and Ω b , the critical temperature can increase or decrease with increasing the thickness of the film, such result is not obtained in the uniform transverse field case (Ω a = Ω b ). Furthermore, for each thickness L of the film, a long range ordered phase persist at low temperature for selected values of the transverse field Ω a and arbitrary values of Ω b . The effects of interlayer and intralayer exchange interactions are also examined

  5. Phosphorylation of dynamin I on Ser-795 by protein kinase C blocks its association with phospholipids

    DEFF Research Database (Denmark)

    Powell, K A; Valova, V A; Malladi, C S

    2000-01-01

    Dynamin I is phosphorylated in nerve terminals exclusively in the cytosolic compartment and in vitro by protein kinase C (PKC). Dephosphorylation is required for synaptic vesicle retrieval, suggesting that its phosphorylation affects its subcellular localization. An in vitro phospholipid binding ...... assay was established that prevents lipid vesiculation and dynamin lipid insertion into the lipid. Dynamin I bound the phospholipid in a concentration-dependent and saturable manner, with an apparent affinity of 230 +/- 51 nM. Optimal binding occurred with mixtures of phosphatidylserine...... the phosphorylation site in PKCalpha-phosphorylated dynamin I as a single site at Ser-795, located near a binding site for the SH3 domain of p85, the regulatory subunit of phosphatidylinositol 3-kinase. However, phosphorylation had no effect on dynamin binding to a bacterially expressed p85-SH3 domain. Thus...

  6. Buried Volume Analysis for Propene Polymerization Catalysis Promoted by Group 4 Metals: a Tool for Molecular Mass Prediction

    KAUST Repository

    Falivene, Laura

    2015-10-02

    A comparison of the steric properties of homogeneous single site catalysts for propene polymerization using the percentage of buried volume (%VBur) as molecular descriptor is reported. The %VBur calculated on the neutral precursors of the active species seems to be a reliable tool to explain several experimental data related to the propene insertion and to the monomer chain transfer. Interestingly, a linear correlation between the buried volume calculated for a large set of neutral precursors and the energetic difference between propagation and termination steps calculated by DFT methods is found for Group 4 metal catalysts. The “master curves” derived for Ti, Zr and Hf confirm not only that the %VBur is an appropriate molecular descriptor for the systems considered but also that it could be used as tool for a large computational screening of new ligands.

  7. Control and Characterization of Titanium Dioxide Morphology: Applications in Surface Organometallic Chemistry

    KAUST Repository

    Jeantelot, Gabriel

    2014-05-01

    Surface Organometallic Chemistry leads to the combination of the high activity and specificity of homogeneous catalysts with the recoverability and practicality of heterogeneous catalysts. Most metal complexes used in this chemistry are grafted on metal oxide supports such as amorphous silica (SiO2) and γ-alumina (Al2O3). In this thesis, we sought to enable the use of titania (TiO2) as a new support for single-site well-defined grafting of metal complexes. This was achieved by synthesizing a special type of anatase-TiO2, bearing a high density of identical hydroxyl groups, through hydrothermal synthesis then post-treatment under high vacuum followed by oxygen flow, and characterized by several analytical techniques including X-ray diffraction, transmission electron microscopy, infrared spectroscopy and nuclear magnetic resonance. Finally, as a proof of concept, the grafting of vanadium oxychloride (VOCl3) was successfully attempted.

  8. Vertical partitioning of relational OLTP databases using integer programming

    DEFF Research Database (Denmark)

    Amossen, Rasmus Resen

    2010-01-01

    A way to optimize performance of relational row store databases is to reduce the row widths by vertically partition- ing tables into table fractions in order to minimize the number of irrelevant columns/attributes read by each transaction. This pa- per considers vertical partitioning algorithms...... for relational row- store OLTP databases with an H-store-like architecture, meaning that we would like to maximize the number of single-sited transactions. We present a model for the vertical partitioning problem that, given a schema together with a vertical partitioning and a workload, estimates the costs...... applied to the TPC-C benchmark and the heuristic is shown to obtain solutions with costs close to the ones found using the quadratic program....

  9. A composite role of vitronectin and urokinase in the modulation of cell morphology upon expression of the urokinase receptor

    DEFF Research Database (Denmark)

    Hillig, Thore; Engelholm, Lars H; Ingvarsen, Signe

    2008-01-01

    The urokinase receptor, urokinase receptor (uPAR), is a glycosylphosphatidylinositol-anchored membrane protein engaged in pericellular proteolysis and cellular adhesion, migration, and modulation of cell morphology. A direct matrix adhesion is mediated through the binding of uPAR to vitronectin......, and this event is followed by downstream effects including changes in the cytoskeletal organization. However, it remains unclear whether the adhesion through uPAR-vitronectin is the only event capable of initiating these morphological rearrangements or whether lateral interactions between uPAR and integrins can...... a different single-site mutant, uPAR(Y57A), in the presence of a synthetic uPAR-binding peptide, as well as with wild-type uPAR, which underwent cytoskeletal rearrangements even when cultivated in uPA-deficient serum. Blocking of integrins with an Arg-Gly-Asp-containing peptide counteracted the matrix...

  10. A comparison of updating algorithms for large N reduced models

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, Margarita García [Instituto de Física Teórica UAM-CSIC, Universidad Autónoma de Madrid,Nicolás Cabrera 13-15, E-28049-Madrid (Spain); González-Arroyo, Antonio [Instituto de Física Teórica UAM-CSIC, Universidad Autónoma de Madrid,Nicolás Cabrera 13-15, E-28049-Madrid (Spain); Departamento de Física Teórica, C-XI Universidad Autónoma de Madrid,E-28049 Madrid (Spain); Keegan, Liam [PH-TH, CERN,CH-1211 Geneva 23 (Switzerland); Okawa, Masanori [Graduate School of Science, Hiroshima University,Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Core of Research for the Energetic Universe, Hiroshima University,Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Ramos, Alberto [PH-TH, CERN,CH-1211 Geneva 23 (Switzerland)

    2015-06-29

    We investigate Monte Carlo updating algorithms for simulating SU(N) Yang-Mills fields on a single-site lattice, such as for the Twisted Eguchi-Kawai model (TEK). We show that performing only over-relaxation (OR) updates of the gauge links is a valid simulation algorithm for the Fabricius and Haan formulation of this model, and that this decorrelates observables faster than using heat-bath updates. We consider two different methods of implementing the OR update: either updating the whole SU(N) matrix at once, or iterating through SU(2) subgroups of the SU(N) matrix, we find the same critical exponent in both cases, and only a slight difference between the two.

  11. A comparison of updating algorithms for large $N$ reduced models

    CERN Document Server

    Pérez, Margarita García; Keegan, Liam; Okawa, Masanori; Ramos, Alberto

    2015-01-01

    We investigate Monte Carlo updating algorithms for simulating $SU(N)$ Yang-Mills fields on a single-site lattice, such as for the Twisted Eguchi-Kawai model (TEK). We show that performing only over-relaxation (OR) updates of the gauge links is a valid simulation algorithm for the Fabricius and Haan formulation of this model, and that this decorrelates observables faster than using heat-bath updates. We consider two different methods of implementing the OR update: either updating the whole $SU(N)$ matrix at once, or iterating through $SU(2)$ subgroups of the $SU(N)$ matrix, we find the same critical exponent in both cases, and only a slight difference between the two.

  12. The use of isothermal titration calorimetry to determine the thermodynamics of metal ion binding to low-cost sorbents

    International Nuclear Information System (INIS)

    Karlsen, Vigdis; Heggset, Ellinor Baevre; Sorlie, Morten

    2010-01-01

    The thermodynamics of Al 3+ , Cr 3+ , and Pb 2+ binding to the abundant biopolymer chitin have been determined using isothermal titration calorimetry (ITC) and compared to what is observed for binding to activated carbon. The use of ITC enables the detection of two distinct binding sites on chitin for all three metal ions. For the relative strong binding sites, free energy changes ranges from -37.6 kJ/mol to -41.8 kJ/mol while the same values are from -30.1 kJ/mol to -31.8 kJ/mol for the relative weak binding sites. All binding reactions to chitin are entropically driven. Interactions of the metal ions to activated carbon are best fitted as a single-site binding with relative weak binding with free energy changes from -26.3 kJ/mol to -26.8 kJ/mol.

  13. Holographic method for site-resolved detection of a 2D array of ultracold atoms

    Science.gov (United States)

    Hoffmann, Daniel Kai; Deissler, Benjamin; Limmer, Wolfgang; Hecker Denschlag, Johannes

    2016-08-01

    We propose a novel approach to site-resolved detection of a 2D gas of ultracold atoms in an optical lattice. A near-resonant laser beam is coherently scattered by the atomic array, and after passing a lens its interference pattern is holographically recorded by superimposing it with a reference laser beam on a CCD chip. Fourier transformation of the recorded intensity pattern reconstructs the atomic distribution in the lattice with single-site resolution. The holographic detection method requires only about two hundred scattered photons per atom in order to achieve a high reconstruction fidelity of 99.9 %. Therefore, additional cooling during detection might not be necessary even for light atomic elements such as lithium. Furthermore, first investigations suggest that small aberrations of the lens can be post-corrected in imaging processing.

  14. Phase diagrams of a spin-1 Ising superlattice with alternating transverse field

    International Nuclear Information System (INIS)

    Saber, A.; Ez-Zahraouy, H.

    2000-09-01

    The effects of alternating transverse fields Ω a and Ω b on the critical behavior of an alternating spin-1 Ising superlattice are studied within an effective field theory with a probability distribution technique that accounts for the single-site spin correlations. Critical temperatures are calculated as a function of the thickness of the superlattice and the strength of the transverse field. Depending on the values of the transverse fields Ω a and Ω b , the critical temperature can increase or decrease with increasing the thickness of the film, such result is not obtained in the uniform transverse field case (Ω a = Ω b ). Furthermore, for each thickness L of the film, a long range ordered phase persists at low temperature for selected values of the transverse field Ω a and arbitrary values of Ω b . The effects of interlayer and intralayer exchange interactions are also examined. (author)

  15. Use of 137Cs in the study of soil erosion and sedimentation

    International Nuclear Information System (INIS)

    1998-07-01

    The use of radionuclides in soil erosion/deposition research overcomes many of the problems associated with traditional approaches and is now being applied successfully in several developed countries. Among these, the 137 Cs technique allows the assessment of both soil loss and deposition in the same watershed from a single site visit without the need for long-term financial commitments. Caesium-137, an artificial radionuclide with a half-life of 30.2 years, is distributed across the earth's surface due to fallout from atmospheric nuclear tests and accidental releases from nuclear reactors. Strongly absorbed by clay particles, it provides a unique tracer of soil movement. In response to the United Nations Conference on Environment and Development convened in Rio de Janeiro in June 1992, the UN system launched a worldwide environmental programme called EARTHWATCH. The IAEA joined this initiative through a series of activities on environmental monitoring, impact assessment and environmental protection

  16. Use of {sup 137}Cs in the study of soil erosion and sedimentation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    The use of radionuclides in soil erosion/deposition research overcomes many of the problems associated with traditional approaches and is now being applied successfully in several developed countries. Among these, the {sup 137}Cs technique allows the assessment of both soil loss and deposition in the same watershed from a single site visit without the need for long-term financial commitments. Caesium-137, an artificial radionuclide with a half-life of 30.2 years, is distributed across the earth`s surface due to fallout from atmospheric nuclear tests and accidental releases from nuclear reactors. Strongly absorbed by clay particles, it provides a unique tracer of soil movement. In response to the United Nations Conference on Environment and Development convened in Rio de Janeiro in June 1992, the UN system launched a worldwide environmental programme called EARTHWATCH. The IAEA joined this initiative through a series of activities on environmental monitoring, impact assessment and environmental protection Refs, figs, tabs

  17. The age of enlightenment: evolving opportunities in brain research through optical manipulation of neuronal activity

    Directory of Open Access Journals (Sweden)

    Jason eJerome

    2011-12-01

    Full Text Available Optical manipulation of neuronal activity has rapidly developed into the most powerful and widely used approach to study mechanisms related to neuronal connectivity over a range of scales. Since the early use of single site uncaging to map network connectivity, rapid technological development of light modulation techniques has added important new options, such as fast scanning photostimulation, massively parallel control of light stimuli, holographic uncaging and 2-photon stimulation techniques. Exciting new developments in optogenetics complement neurotransmitter uncaging techniques by providing cell-type specificity and in vivo usability, providing optical access to the neural substrates of behavior. Here we review the rapid evolution of methods for the optical manipulation of neuronal activity, emphasizing crucial recent developments.

  18. The age of enlightenment: evolving opportunities in brain research through optical manipulation of neuronal activity.

    Science.gov (United States)

    Jerome, Jason; Heck, Detlef H

    2011-01-01

    Optical manipulation of neuronal activity has rapidly developed into the most powerful and widely used approach to study mechanisms related to neuronal connectivity over a range of scales. Since the early use of single site uncaging to map network connectivity, rapid technological development of light modulation techniques has added important new options, such as fast scanning photostimulation, massively parallel control of light stimuli, holographic uncaging, and two-photon stimulation techniques. Exciting new developments in optogenetics complement neurotransmitter uncaging techniques by providing cell-type specificity and in vivo usability, providing optical access to the neural substrates of behavior. Here we review the rapid evolution of methods for the optical manipulation of neuronal activity, emphasizing crucial recent developments.

  19. REopt Screenings Catalyze Development of Hundreds of Megawatts of Renewable Energy for Federal Agencies

    Energy Technology Data Exchange (ETDEWEB)

    2017-04-24

    The U.S. Department of Energy's (DOE's) Federal Energy Management Program (FEMP) offers project assistance to federal agencies, which often begins with a desktop screening to develop a prioritized portfolio of renewable energy project opportunities. FEMP uses the National Renewable Energy Laboratory's (NREL) REopt energy planning platform to quickly and efficiently screen potential renewable energy opportunities at a single site or across a range of sites. REopt helps organizations prioritize the most economically and technically viable projects for further study, and identifies the size and mix of technologies that meet the organization's goals at minimum cost, along with the optimal operating strategies.

  20. Thermoelectric effects in a rectangular Aharonov-Bohm geometry

    Science.gov (United States)

    Pye, A. J.; Faux, D. A.; Kearney, M. J.

    2016-04-01

    The thermoelectric transport properties of a rectangular Aharonov-Bohm ring at low temperature are investigated using a theoretical approach based on Green's functions. The oscillations in the transmission coefficient as the field is varied can be used to tune the thermoelectric response of the ring. Large magnitude thermopowers are obtainable which, in conjunction with low conductance, can result in a high thermoelectric figure of merit. The effects of single site impurities and more general Anderson disorder are considered explicitly in the context of evaluating their effect on the Fano-type resonances in the transmission coefficient. Importantly, it is shown that even for moderate levels of disorder, the thermoelectric figure of merit can remain significant, increasing the appeal of such structures from the perspective of specialist thermoelectric applications.

  1. Effective field theory with differential operator technique for dynamic phase transition in ferromagnetic Ising model

    International Nuclear Information System (INIS)

    Kinoshita, Takehiro; Fujiyama, Shinya; Idogaki, Toshihiro; Tokita, Masahiko

    2009-01-01

    The non-equilibrium phase transition in a ferromagnetic Ising model is investigated by use of a new type of effective field theory (EFT) which correctly accounts for all the single-site kinematic relations by differential operator technique. In the presence of a time dependent oscillating external field, with decrease of the temperature the system undergoes a dynamic phase transition, which is characterized by the period averaged magnetization Q, from a dynamically disordered state Q = 0 to the dynamically ordered state Q ≠ 0. The results of the dynamic phase transition point T c determined from the behavior of the dynamic magnetization and the Liapunov exponent provided by EFT are improved than that of the standard mean field theory (MFT), especially for the one dimensional lattice where the standard MFT gives incorrect result of T c = 0 even in the case of zero external field.

  2. Proton and Electron Additions to Iron (II) Dinitrogen Complexes Containing Pendant Amines

    Energy Technology Data Exchange (ETDEWEB)

    Heiden, Zachariah M.; Chen, Shentan; Labios, Liezel AN; Bullock, R. Morris; Walter, Eric D.; Tyson, Elizabeth L.; Mock, Michael T.

    2014-03-10

    We describe a single site cis-(H)FeII-N2 complex, generated by the protonation of an iron-carbon bond of a "reduced" iron complex, that models key aspects of proposed protonated intermediates of the E4 state of nitrogenase. The influence on N2 binding from the addition of protons to the pendant amine sites in the second coordination sphere is described. Furthermore, the addition of electrons to the protonated complexes results in H2 loss. The mechanism of H2 loss is explored to draw a parallel to the origin of H2 loss (homolytic or heterolytic) and the nature of N2 coordination in intermediates of the E4 state of nitrogenase.

  3. Plant diversity predicts beta but not alpha diversity of soil microbes across grasslands worldwide

    Science.gov (United States)

    Prober, Suzanne M.; Leff, Jonathan W.; Bates, Scott T.; Borer, Elizabeth T.; Firn, Jennifer; Harpole, W. Stanley; Lind, Eric M.; Seabloom, Eric W.; Adler, Peter B.; Bakker, Jonathan D.; Cleland, Elsa E.; DeCrappeo, Nicole; DeLorenze, Elizabeth; Hagenah, Nicole; Hautier, Yann; Hofmockel, Kirsten S.; Kirkman, Kevin P.; Knops, Johannes M. H.; La Pierre, Kimberly J.; MacDougall, Andrew S.; McCulley, Rebecca L.; Mitchell, Charles E.; Risch, Anita C.; Schuetz, Martin; Stevens, Carly J.; Williams, Ryan J.; Fierer, Noah

    2015-01-01

    Aboveground–belowground interactions exert critical controls on the composition and function of terrestrial ecosystems, yet the fundamental relationships between plant diversity and soil microbial diversity remain elusive. Theory predicts predominantly positive associations but tests within single sites have shown variable relationships, and associations between plant and microbial diversity across broad spatial scales remain largely unexplored. We compared the diversity of plant, bacterial, archaeal and fungal communities in one hundred and forty-five 1 m2 plots across 25 temperate grassland sites from four continents. Across sites, the plant alpha diversity patterns were poorly related to those observed for any soil microbial group. However, plant beta diversity (compositional dissimilarity between sites) was significantly correlated with the beta diversity of bacterial and fungal communities, even after controlling for environmental factors. Thus, across a global range of temperate grasslands, plant diversity can predict patterns in the composition of soil microbial communities, but not patterns in alpha diversity.

  4. An albumin-oligonucleotide assembly for potential combinatorial drug delivery and half-life extension applications

    DEFF Research Database (Denmark)

    Kuhlmann, Matthias; Hamming, Jonas Bohn Refslund; Voldum, Anders

    2017-01-01

    The long blood circulatory property of human serum albumin, due to engagement with the cellular recycling neonatal Fc receptor (FcRn), is an attractive drug half-life extension enabling technology. This work describes a novel site-specific albumin double-stranded (ds) DNA assembly approach, in wh...... technology platform that offers potential combinatorial drug delivery and half-life extension applications.......The long blood circulatory property of human serum albumin, due to engagement with the cellular recycling neonatal Fc receptor (FcRn), is an attractive drug half-life extension enabling technology. This work describes a novel site-specific albumin double-stranded (ds) DNA assembly approach......, in which the 3' or 5' end maleimide-derivatized oligodeoxynucleotides are conjugated to albumin cysteine at position 34 (cys34) and annealed with complementary strands to allow single site-specific protein modification with functionalized ds oligodeoxynucleotides. Electrophoretic gel shift assays...

  5. A silica-supported double-decker silsesquioxane provides a second skin for the selective generation of bipodal surface organometallic complexes

    KAUST Repository

    Espinas, Jeff; Pelletier, Jeremie; Abou-Hamad, Edy; Emsley, Lyndon; Basset, Jean-Marie

    2012-01-01

    A well-defined silica-based material with a homogeneous nanolayer presenting identical pairs of vicinal silanols has been prepared by reaction of the surface organometallic species [≡SiOZr(CH 2CMe 3) 3], obtained on a silica dehydroxylated at 900 °C, with the double-decker-shaped silsesquioxane (OH) 2DD(OH) 2. The surface structure has been established using extensive NMR characterization ( 1H, 13C, 29Si, HETCOR, double-quantum, triple-quantum). Treatment with Zr(CH 2CMe 3) 4 leads to the first well-defined single-site bipodal grafted bis-neopentyl zirconium complex. © 2012 American Chemical Society.

  6. Readily releasable pool of synaptic vesicles measured at single synaptic contacts.

    Science.gov (United States)

    Trigo, Federico F; Sakaba, Takeshi; Ogden, David; Marty, Alain

    2012-10-30

    To distinguish between different models of vesicular release in brain synapses, it is necessary to know the number of vesicles of transmitter that can be released immediately at individual synapses by a high-calcium stimulus, the readily releasable pool (RRP). We used direct stimulation by calcium uncaging at identified, single-site inhibitory synapses to investigate the statistics of vesicular release and the size of the RRP. Vesicular release, detected as quantal responses in the postsynaptic neuron, showed an unexpected stochastic variation in the number of quanta from stimulus to stimulus at high intracellular calcium, with a mean of 1.9 per stimulus and a maximum of three or four. The results provide direct measurement of the RRP at single synaptic sites. They are consistent with models in which release proceeds from a small number of vesicle docking sites with an average occupancy around 0.7.

  7. High-level radioactive waste management in the United States. Background and status: 1996

    International Nuclear Information System (INIS)

    Dyer, J.R.

    1996-01-01

    The US high-level radioactive waste disposal program is investigating a site at Yucca Mountain, Nevada, to determine whether or not it is a suitable location for the development of a deep mined geologic repository. At this time, the US program is investigating a single site, although in the past, the program involved successive screening and comparison of alternate locations. The United States civilian reactor programs do not reprocess spent fuel; the high-level waste repository will be designed for the emplacement or spent fuel and a limited amount of vitrified high-level wastes from previous reprocessing in the US. The legislation enabling the US program also contains provisions for a Monitored Retrievable Storage facility, which could provide temporary storage of spent fuel accepted for disposal, and improve the flexibility of the repository development schedule

  8. Theory of singlet-doublet excitations in praseodymium

    International Nuclear Information System (INIS)

    Bak, P.

    1975-10-01

    The magnetic excitation spectrum in a paramagnetic singlet-doublet system is calculated using a diagrammatic high density expansion technique. The lowest order diagrams, which correspond to the random phase approximation (RPA), give a detailed description of the wave vector and temperature dependence of the four exciton modes in praseodymium in terms of a Hamiltonian including isotropic Heisenberg exchange interactions and anisotropic, dipolar-like interactions. The leading contributions to the linewidths of the excitations are obtained by extending the 1/Z expansion of the generalized susceptibility propagators one order beyond the random phase approximation. This damping corresponds to spin wave scattering on single-site fluctuations. The theoretical spectral functions are in detailed agreement with experiment

  9. Composition-driven Cu-speciation and reducibility in Cu-CHA zeolite catalysts: a multivariate XAS/FTIR approach to complexity† †Electronic supplementary information (ESI) available: Sample description and synthesis details, experimental setup for in situ XAS and FTIR spectroscopy, details on the MCR-ALS method, details on DFT-assisted XANES simulations, details on the determination of N pure by PCA, MCR-ALS results for downsized and upsized component spaces, additional information to support the assignment of theoretical XANES curves, details on EXAFS analysis, details on IR spectral deconvolution. See DOI: 10.1039/c7sc02266b Click here for additional data file.

    Science.gov (United States)

    Martini, A.; Lomachenko, K. A.; Pankin, I. A.; Negri, C.; Berlier, G.; Beato, P.; Falsig, H.; Bordiga, S.; Lamberti, C.

    2017-01-01

    The small pore Cu-CHA zeolite is attracting increasing attention as a versatile platform to design novel single-site catalysts for deNOx applications and for the direct conversion of methane to methanol. Understanding at the atomic scale how the catalyst composition influences the Cu-species formed during thermal activation is a key step to unveil the relevant composition–activity relationships. Herein, we explore by in situ XAS the impact of Cu-CHA catalyst composition on temperature-dependent Cu-speciation and reducibility. Advanced multivariate analysis of in situ XANES in combination with DFT-assisted simulation of XANES spectra and multi-component EXAFS fits as well as in situ FTIR spectroscopy of adsorbed N2 allow us to obtain unprecedented quantitative structural information on the complex dynamics during the speciation of Cu-sites inside the framework of the CHA zeolite. PMID:29147509

  10. New maneuver in robotic single-port cholecystectomy

    International Nuclear Information System (INIS)

    Ege, B.; Gulen, M.

    2017-01-01

    The need to integrate aspects of functional, psychosocial and cosmetic impairment into medical care is increasingly accepted among the physicians and the patients. For these reasons, single-port robotic surgery emerges as the most advanced approach using the technology. In this study, authors used a new robotic dissector with monopolar electrocautery feature in order to determine the device's safety and efficacy. Between January 2015 and February 2016, 10 out of 11 consecutive cholecystectomies were included in the study. There was no significant differences in port placement and docking time between two groups (p=0.382, p=0.789). The time spent by surgeon was significantly shorter in group 2 (p=0.005). Using robotic dissector with monopolar cautery significantly shortened the console time. This new instrument (Maryland monopolar dissector) provides more feasible and faster dissection of the Calot's triangle, supporting further the advantages of robotic single-site cholecystectomy. (author)

  11. Neutron scattering in disordered alloys: coherent and incoherent intensities

    International Nuclear Information System (INIS)

    Mookerjee, A.; Yussouff, M.

    1985-02-01

    A priori it is not clear how to split the total intensity of thermal neutron scattering from disordered alloys into a coherent and an incoherent part. We present here a formalism to do this. The formalism is based on the augmented space technique introduced earlier by one of the authors. It includes disorder in mass, force constants and scattering lengths. A self-consistent CCPA which is tractable for realistic calculations is presented for the coherent and incoherent intensities. This is expected to prove useful in theoretically analysis data for alloys (e.g. Nisub(x)Ptsub(1-x), Nisub(x)Pdsub(1-x), Nisub(x)Crsub(1-x)) for which it is necessary to go beyond the usual single site CPAs for reliable accuracy. (author)

  12. Relativistic studies in actinides

    International Nuclear Information System (INIS)

    Weinberger, P.; Gonis, A.

    1987-01-01

    In this review the theoretical background is given for a relativistic description for actinide systems. A short introduction is given of the density functional theory which forms the basis for a fully relativistic single-particle theory. A section on the Dirac Hamiltonian is followed by a brief summary on group theoretical concepts. Single site scattering is presented such that formal extensions to the case of the presence of an internal (external) magnetic field and/or anisotropic scattering are evident. Multiple scattering is discussed such that it can readily be applied also to the problem of dislocations. In connection with the problem of selfconsistency particular attention is drawn to the use of complex energies. Finally the various theoretical aspects discussed are illustrated through the results of numerical calculations. 101 refs.; 37 figs.; 5 tabs

  13. Flexible single-incision surgery: a fusion technique.

    Science.gov (United States)

    Noguera, José F; Dolz, Carlos; Cuadrado, Angel; Olea, José; García, Juan

    2013-06-01

    The development of natural orifice transluminal endoscopic surgery has led to other techniques, such as single-incision surgery. The use of the flexible endoscope for single-incision surgery paves the way for further refinement of both surgical methods. To describe a new, single-incision surgical technique, namely, flexible single-incision surgery. Assessment of the safety and effectiveness of endoscopic cholecystectomy in a series of 30 patients. This technique consists of a single umbilical incision through which a flexible endoscope is introduced and consists of 2 parallel entry ports that provide access to nonarticulated laparoscopic instruments. The technique was applied in all patients for whom it was prescribed. No general or surgical wound complications were noted. Surgical time was no longer than usual for single-port surgery. Flexible single-incision surgery is a new single-site surgical technique offering the same level of patient safety, with additional advantages for the surgeon at minimal cost.

  14. Screening for carcinoma in situ in the contralateral testicle in patients with testicular cancer

    DEFF Research Database (Denmark)

    Kier, M G G; Lauritsen, Jakob; Almstrup, Kristian

    2015-01-01

    population-based screening programme for contralateral CIS in patients with testicular cancer showed no significant difference in the risk for metachronous GCC between a screened and an unscreened cohort. Single-site biopsy including modern immunohistochemistry does not identify all cases of CIS.......BACKGROUND: Screening programmes for contralateral carcinoma in situ (CIS) testis in patients with unilateral germ-cell cancer (GCC) have never been evaluated. We investigated the effect of screening for contralateral CIS in a large nation-wide, population-based study. PATIENTS AND METHODS...... years was 1.9% in the screened cohort and 3.1% in the unscreened cohort (P = 0.097), hazard ratio (HR) for the unscreened cohort: 1.59 (P = 0.144). Expert revision with contemporary methodology of CIS-negative biopsy samples from patients with metachronous cancer revealed CIS in 17 out of 45 (38%) cases...

  15. In situ mapping of the hsp70 locus in seven species of the willistoni group of Drosophila

    International Nuclear Information System (INIS)

    Bonorino, C.B.C.; Valente, V.L.S.; Pereira, M.; Alonso, C.E.V.; Abdelhay, E.

    1993-01-01

    The hsp70 locus was mapped by in situ hybridization of a biotinylated probe (p PW 229) to the polythene chromosomes of seven species of the willistoni group of Drosophila. In all of them, the probe hybridized mainly at a single site of the third chromosome, corresponding in each case to a heat-induced puff site. Southern blot analysis comparing the Eco RI digested DNA of the willistoni species with D. melanogaster revealed that a large segment of DNA homologous to the hsp 70 probe detected in D. melanogaster does not exist in the willistoni group. These results suggested that this locus is not duplicated in the willistoni group as it is in the melanogaster. (author)

  16. OILMAP: A global approach to spill modeling

    International Nuclear Information System (INIS)

    Spaulding, M.L.; Howlett, E.; Anderson, E.; Jayko, K.

    1992-01-01

    OILMAP is an oil spill model system suitable for use in both rapid response mode and long-range contingency planning. It was developed for a personal computer and employs full-color graphics to enter data, set up spill scenarios, and view model predictions. The major components of OILMAP include environmental data entry and viewing capabilities, the oil spill models, and model prediction display capabilities. Graphic routines are provided for entering wind data, currents, and any type of geographically referenced data. Several modes of the spill model are available. The surface trajectory mode is intended for quick spill response. The weathering model includes the spreading, evaporation, entrainment, emulsification, and shoreline interaction of oil. The stochastic and receptor models simulate a large number of trajectories from a single site for generating probability statistics. Each model and the algorithms they use are described. Several additional capabilities are planned for OILMAP, including simulation of tactical spill response and subsurface oil transport. 8 refs

  17. Final Technical Report: Metal—Organic Surface Catalyst for Low-temperature Methane Oxidation: Bi-functional Union of Metal—Organic Complex and Chemically Complementary Surface

    Energy Technology Data Exchange (ETDEWEB)

    Tait, Steven L. [Indiana Univ., Bloomington, IN (United States)

    2016-10-01

    Stabilization and chemical control of transition metal centers is a critical problem in the advancement of heterogeneous catalysts to next-generation catalysts that exhibit high levels of selectivity, while maintaining strong activity and facile catalyst recycling. Supported metal nanoparticle catalysts typically suffer from having a wide range of metal sites with different coordination numbers and varying chemistry. This project is exploring new possibilities in catalysis by combining features of homogeneous catalysts with those of heterogeneous catalysts to develop new, bi-functional systems. The systems are more complex than traditional heterogeneous catalysts in that they utilize sequential active sites to accomplish the desired overall reaction. The interaction of metal—organic catalysts with surface supports and their interactions with reactants to enable the catalysis of critical reactions at lower temperatures are at the focus of this study. Our work targets key fundamental chemistry problems. How do the metal—organic complexes interact with the surface? Can those metal center sites be tuned for selectivity and activity as they are in the homogeneous system by ligand design? What steps are necessary to enable a cooperative chemistry to occur and open opportunities for bi-functional catalyst systems? Study of these systems will develop the concept of bringing together the advantages of heterogeneous catalysis with those of homogeneous catalysis, and take this a step further by pursuing the objective of a bi-functional system. The use of metal-organic complexes in surface catalysts is therefore of interest to create well-defined and highly regular single-site centers. While these are not likely to be stable in the high temperature environments (> 300 °C) typical of industrial heterogeneous catalysts, they could be applied in moderate temperature reactions (100-300 °C), made feasible by lowering reaction temperatures by better catalyst control. They also

  18. A set of lacZ mutations in Escherichia coli that allow rapid detection of each of the six base substitutions

    International Nuclear Information System (INIS)

    Cupples, C.G.; Miller, J.H.

    1989-01-01

    We describe the construction of six strains of Escherichia coli with different mutations at the same coding position in the lacZ gene, which specifies the active site glutamic acid residue at position 461 in beta'-galactosidase. Each strain is Lac- and reverts to Lac+ only by restoring the glutamic acid codon. The strains have been designed so that each reverts via one of the six base substitutions. The set of strains allows detection of each transition and transversion simply by monitoring the Lac- to Lac+ frequency, as demonstrated here with characterized mutagens and mutator alleles. These strains are useful for rapidly determining the mutagenic specificity of mutagens at a single site, for detecting low levels of stimulation of certain base substitutions, for monitoring specific base changes in response to various experimental conditions or strain backgrounds, and for isolating new mutator strains

  19. The effect of single oral doses of duloxetine, reboxetine, and midodrine on the urethral pressure in healthy female subjects, using urethral pressure reflectometry

    DEFF Research Database (Denmark)

    Klarskov, Niels; Cerneus, Dirk; Sawyer, William

    2018-01-01

    AIMS: To evaluate the effect on urethral pressure of reference drugs known to reduce stress urinary incontinence symptoms by different effect size and mechanisms of action on urethral musculature under four test conditions in healthy female subjects using urethral pressure reflectometry. METHODS......: Healthy females aged 18-55 years were recruited by advertising for this phase 1, single site, placebo-controlled, randomized, four-period, crossover study. The interventions were single oral doses of 10 mg Midodrine, 80 mg Duloxetine, 12 mg Reboxetine, and placebo. The endpoints were the opening urethral...... pressure measured in each period at four time points (predose and 2, 5.5, and 9 h after dosing). RESULTS: Twenty-nine females were enrolled; 25 randomized and 24 completed the study. The opening urethral pressure was higher in all measurements with filled bladder compared with empty bladder, and during...

  20. 'Stroke Room': Diagnosis and Treatment at a Single Location for Rapid Intraarterial Stroke Treatment.

    Science.gov (United States)

    Ragoschke-Schumm, Andreas; Yilmaz, Umut; Kostopoulos, Panagiotis; Lesmeister, Martin; Manitz, Matthias; Walter, Silke; Helwig, Stefan; Schwindling, Lenka; Fousse, Mathias; Haass, Anton; Garner, Dominique; Körner, Heiko; Roumia, Safwan; Grunwald, Iris; Nasreldein, Ali; Halmer, Ramona; Liu, Yang; Schlechtriemen, Thomas; Reith, Wolfgang; Fassbender, Klaus

    2015-01-01

    For patients with acute ischemic stroke, intra-arterial treatment (IAT) is considered to be an effective strategy for removing the obstructing clot. Because outcome crucially depends on time to treatment ('time-is-brain' concept), we assessed the effects of an intervention based on performing all the time-sensitive diagnostic and therapeutic procedures at a single location on the delay before intra-arterial stroke treatment. Consecutive acute stroke patients with large vessel occlusion who obtained IAT were evaluated before and after implementation (April 26, 2010) of an intervention focused on performing all the diagnostic and therapeutic measures at a single site ('stroke room'). After implementation of the intervention, the median intervals between admission and first angiography series were significantly shorter for 174 intervention patients (102 min, interquartile range (IQR) 85-120 min) than for 81 control patients (117 min, IQR 89-150 min; p room') saves crucial time until IAT. © 2015 S. Karger AG, Basel.

  1. Forbidden atomic transitions driven by an intensity-modulated laser trap.

    Science.gov (United States)

    Moore, Kaitlin R; Anderson, Sarah E; Raithel, Georg

    2015-01-20

    Spectroscopy is an essential tool in understanding and manipulating quantum systems, such as atoms and molecules. The model describing spectroscopy includes the multipole-field interaction, which leads to established spectroscopic selection rules, and an interaction that is quadratic in the field, which is not often employed. However, spectroscopy using the quadratic (ponderomotive) interaction promises two significant advantages over spectroscopy using the multipole-field interaction: flexible transition rules and vastly improved spatial addressability of the quantum system. Here we demonstrate ponderomotive spectroscopy by using optical-lattice-trapped Rydberg atoms, pulsating the lattice light and driving a microwave atomic transition that would otherwise be forbidden by established spectroscopic selection rules. This ability to measure frequencies of previously inaccessible transitions makes possible improved determinations of atomic characteristics and constants underlying physics. The spatial resolution of ponderomotive spectroscopy is orders of magnitude better than the transition frequency would suggest, promising single-site addressability in dense particle arrays for quantum computing applications.

  2. Characterization of (/sup 3/H)paroxetine binding in rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Marcusson, J.O.; Bergstroem, M.E.; Eriksson, K.; Ross, S.B.

    1988-06-01

    The binding of the 5-hydroxytryptamine (5-HT, serotonin) uptake inhibitor (3H)paroxetine to rat cortical homogenates has been characterized. The effect of tissue concentration was examined and, with 0.75 mg wet weight tissue/ml in a total volume of 1,600 microliter, the binding was optimized with an apparent dissociation constant (KD) of 0.03-0.05 nM. Competition experiments with 5-HT, citalopram, norzimeldine, and desipramine revealed a high (90%) proportion of displaceable binding that fitted a single-site binding model. Fluoxetine and imipramine revealed, in addition to a high-affinity (nanomolar) site, also a low-affinity (micromolar) site representing approximately 10% of the displaceable binding. The specificity of the (3H)paroxetine binding was emphasized by the fact that 5-HT was the only active neurotransmitter bound and that the serotonin S1 and S2 antagonist methysergide was without effect on the binding. Both 5-HT- and fluoxetine-sensitive (3H)paroxetine binding was completely abolished after protease treatment, suggesting that the binding site is of protein nature. Saturation studies with 5-HT (100 microM) sensitive (3H)paroxetine binding were also consistent with a single-site binding model, and the binding was competitively inhibited by 5-HT and imipramine. The number of binding sites (Bmax) for 5-HT-sensitive (3H)paroxetine and (3H)imipramine binding was the same, indicating that the radioligands bind to the same sites. Lesion experiments with p-chloroamphetamine resulted in a binding in frontal and parietal cortices becoming undetectable and a greater than 60% reduction in the striatum and hypothalamus, indicating a selective localization on 5-HT terminals. Together these findings suggest that (3H)paroxetine specifically and selectively labels the substrate recognition site for 5-HT uptake in rat brain.

  3. Whole body cardiovascular magnetic resonance imaging to stratify symptomatic and asymptomatic atherosclerotic burden in patients with isolated cardiovascular disease

    International Nuclear Information System (INIS)

    Weir-McCall, Jonathan R.; Duce, Suzanne L.; Gandy, Stephen J.; Matthew, Shona Z.; Martin, Patricia; Cassidy, Deirdre B.; McCormick, Lynne; Belch, Jill J. F.; Struthers, Allan D.; Colhoun, Helen M.; Houston, J. Graeme

    2016-01-01

    The aim of this study was to use whole body cardiovascular magnetic resonance imaging (WB CVMR) to assess the heart and arterial network in a single examination, so as to describe the burden of atherosclerosis and subclinical disease in participants with symptomatic single site vascular disease. 64 patients with a history of symptomatic single site vascular disease (38 coronary artery disease (CAD), 9 cerebrovascular disease, 17 peripheral arterial disease (PAD)) underwent whole body angiogram and cardiac MR in a 3 T scanner. The arterial tree was subdivided into 31 segments and each scored according to the degree of stenosis. From this a standardised atheroma score (SAS) was calculated. Cine and late gadolinium enhancement images of the left ventricle were obtained. Asymptomatic atherosclerotic disease with greater than 50 % stenosis in arteries other than that responsible for their presenting complain was detected in 37 % of CAD, 33 % of cerebrovascular and 47 % of PAD patients. Unrecognised myocardial infarcts were observed in 29 % of PAD patients. SAS was significantly higher in PAD patients 24 (17.5-30.5) compared to CAD 4 (2–11.25) or cerebrovascular disease patients 6 (2-10) (ANCOVA p < 0.001). Standardised atheroma score positively correlated with age (β 0.36 p = 0.002), smoking status (β 0.34 p = 0.002), and LV mass (β -0.61 p = 0.001) on multiple linear regression. WB CVMR is an effective method for the stratification of cardiovascular disease. The high prevalence of asymptomatic arterial disease, and silent myocardial infarctions, particularly in the peripheral arterial disease group, demonstrates the importance of a systematic approach to the assessment of cardiovascular disease

  4. The impact of genetic heterogeneity on biomarker development in kidney cancer assessed by multiregional sampling

    International Nuclear Information System (INIS)

    Sankin, Alexander; Hakimi, Abraham A; Mikkilineni, Nina; Ostrovnaya, Irina; Silk, Mikhail T; Liang, Yupu; Mano, Roy; Chevinsky, Michael; Motzer, Robert J; Solomon, Stephen B; Cheng, Emily H; Durack, Jeremy C; Coleman, Jonathan A; Russo, Paul; Hsieh, James J

    2014-01-01

    Primary clear cell renal cell carcinoma (ccRCC) genetic heterogeneity may lead to an underestimation of the mutational burden detected from a single site evaluation. We sought to characterize the extent of clonal branching involving key tumor suppressor mutations in primary ccRCC and determine if genetic heterogeneity could limit the mutation profiling from a single region assessment. Ex vivo core needle biopsies were obtained from three to five different regions of resected renal tumors at a single institution from 2012 to 2013. DNA was extracted and targeted sequencing was performed on five genes associated with ccRCC (von-Hippel Lindau [VHL], PBRM1, SETD2, BAP1, and KDM5C). We constructed phylogenetic trees by inferring clonal evolution based on the mutations present within each core and estimated the predictive power of detecting a mutation for each successive tumor region sampled. We obtained 47 ex vivo biopsy cores from 14 primary ccRCC's (median tumor size 4.5 cm, IQR 4.0–5.9 cm). Branching patterns of various complexities were observed in tumors with three or more mutations. A VHL mutation was detected in nine tumors (64%), each time being present ubiquitously throughout the tumor. Other genes had various degrees of regional mutational variation. Based on the mutations' prevalence we estimated that three different tumor regions should be sampled to detect mutations in PBRM1, SETD2, BAP1, and/or KDM5C with 90% certainty. The mutational burden of renal tumors varies by region sampled. Single site assessment of key tumor suppressor mutations in primary ccRCC may not adequately capture the genetic predictors of tumor behavior

  5. Statistical significance of cis-regulatory modules

    Directory of Open Access Journals (Sweden)

    Smith Andrew D

    2007-01-01

    Full Text Available Abstract Background It is becoming increasingly important for researchers to be able to scan through large genomic regions for transcription factor binding sites or clusters of binding sites forming cis-regulatory modules. Correspondingly, there has been a push to develop algorithms for the rapid detection and assessment of cis-regulatory modules. While various algorithms for this purpose have been introduced, most are not well suited for rapid, genome scale scanning. Results We introduce methods designed for the detection and statistical evaluation of cis-regulatory modules, modeled as either clusters of individual binding sites or as combinations of sites with constrained organization. In order to determine the statistical significance of module sites, we first need a method to determine the statistical significance of single transcription factor binding site matches. We introduce a straightforward method of estimating the statistical significance of single site matches using a database of known promoters to produce data structures that can be used to estimate p-values for binding site matches. We next introduce a technique to calculate the statistical significance of the arrangement of binding sites within a module using a max-gap model. If the module scanned for has defined organizational parameters, the probability of the module is corrected to account for organizational constraints. The statistical significance of single site matches and the architecture of sites within the module can be combined to provide an overall estimation of statistical significance of cis-regulatory module sites. Conclusion The methods introduced in this paper allow for the detection and statistical evaluation of single transcription factor binding sites and cis-regulatory modules. The features described are implemented in the Search Tool for Occurrences of Regulatory Motifs (STORM and MODSTORM software.

  6. DC-Analyzer-facilitated combinatorial strategy for rapid directed evolution of functional enzymes with multiple mutagenesis sites.

    Science.gov (United States)

    Wang, Xiong; Zheng, Kai; Zheng, Huayu; Nie, Hongli; Yang, Zujun; Tang, Lixia

    2014-12-20

    Iterative saturation mutagenesis (ISM) has been shown to be a powerful method for directed evolution. In this study, the approach was modified (termed M-ISM) by combining the single-site saturation mutagenesis method with a DC-Analyzer-facilitated combinatorial strategy, aiming to evolve novel biocatalysts efficiently in the case where multiple sites are targeted simultaneously. Initially, all target sites were explored individually by constructing single-site saturation mutagenesis libraries. Next, the top two to four variants in each library were selected and combined using the DC-Analyzer-facilitated combinatorial strategy. In addition to site-saturation mutagenesis, iterative saturation mutagenesis also needed to be performed. The advantages of M-ISM over ISM were that the screening effort is greatly reduced, and the entire M-ISM procedure was less time-consuming. The M-ISM strategy was successfully applied to the randomization of halohydrin dehalogenase from Agrobacterium radiobacter AD1 (HheC) when five interesting sites were targeted simultaneously. After screening 900 clones in total, six positive mutants were obtained. These mutants exhibited 4.0- to 9.3-fold higher k(cat) values than did the wild-type HheC toward 1,3-dichloro-2-propanol. However, with the ISM strategy, the best hit showed a 5.9-fold higher k(cat) value toward 1,3-DCP than the wild-type HheC, which was obtained after screening 4000 clones from four rounds of mutagenesis. Therefore, M-ISM could serve as a simple and efficient version of ISM for the randomization of target genes with multiple positions of interest.

  7. Viral Warts-A Clinico-Epidemiological Study

    Directory of Open Access Journals (Sweden)

    Laxmisha Chandrashekar

    2003-01-01

    Full Text Available Although clinical criteria, laboratory diagnosis and treatment are well established, scanty attention has been paid to prevalence and pattern of viral warts in India. HIV is widely prevalent and its influence on the number and morphology of viral warts has not yet been studied in our setup. Hence, this study was undertaken. One hindered and forty four cases of viral warts were studied between September 2000 and June 2002 at the department of Dermatology and STD, JIPMER, Pondicherry. These included 81childeren and 63 adults. In Children, viral warts were most commonly seen in the age group of 10to14 years (41.9%, whereas in adults, the most commonly seen in the age 14to20 years (46.03%. The average age at presentation was 11.5 years. The male to female ratio was 2.2 to 1 in children and 1.8 to 1 in adults. Family history of warts was observed in 27.7% of the cases. In children, multiple site involvement (62.9% was more common than single site involvement. The most commonly involved site was hand in children as also in adults. In adults, single site involvement (66.6%was more common than multiple site involvement. The most common type of wart seen in both children and adults was the common wart. Twenty percent of the cases showed koebnerization. Four cases were found to be seropositive for HIV infection, who were adult with genital warts, but florid manifestations were not seen.

  8. F429 Regulation of Tunnels in Cytochrome P450 2B4: A Top Down Study of Multiple Molecular Dynamics Simulations.

    Directory of Open Access Journals (Sweden)

    Giordano Mancini

    Full Text Available The root causes of the outcomes of the single-site mutation in enzymes remain by and large not well understood. This is the case of the F429H mutant of the cytochrome P450 (CYP 2B4 enzyme where the substitution, on the proximal surface of the active site, of a conserved phenylalanine 429 residue with histidine seems to hamper the formation of the active species, Compound I (porphyrin cation radical-Fe(IV = O, Cpd I from the ferric hydroperoxo (Fe(IIIOOH-, Cpd 0 precursor. Here we report a study based on extensive molecular dynamic (MD simulations of 4 CYP-2B4 point mutations compared to the WT enzyme, having the goal of better clarifying the importance of the proximal Phe429 residue on CYP 2B4 catalytic properties. To consolidate the huge amount of data coming from five simulations and extract the most distinct structural features of the five species studied we made an extensive use of cluster analysis. The results show that all studied single polymorphisms of F429, with different side chain properties: i drastically alter the reservoir of conformations accessible by the protein, perturbing global dynamics ii expose the thiolate group of residue Cys436 to the solvent, altering the electronic properties of Cpd0 and iii affect the various ingress and egress channels connecting the distal sites with the bulk environment, altering the reversibility of these channels. In particular, it was observed that the wild type enzyme exhibits unique structural features as compared to all mutant species in terms of weak interactions (hydrogen bonds that generate a completely different dynamical behavior of the complete system. Albeit not conclusive, the current computational investigation sheds some light on the subtle and critical effects that proximal single-site mutations can exert on the functional mechanisms of human microsomal CYPs which should go rather far beyond local structure characterization.

  9. Multi-site calibration, validation, and sensitivity analysis of the MIKE SHE Model for a large watershed in northern China

    Directory of Open Access Journals (Sweden)

    S. Wang

    2012-12-01

    Full Text Available Model calibration is essential for hydrologic modeling of large watersheds in a heterogeneous mountain environment. Little guidance is available for model calibration protocols for distributed models that aim at capturing the spatial variability of hydrologic processes. This study used the physically-based distributed hydrologic model, MIKE SHE, to contrast a lumped calibration protocol that used streamflow measured at one single watershed outlet to a multi-site calibration method which employed streamflow measurements at three stations within the large Chaohe River basin in northern China. Simulation results showed that the single-site calibrated model was able to sufficiently simulate the hydrographs for two of the three stations (Nash-Sutcliffe coefficient of 0.65–0.75, and correlation coefficient 0.81–0.87 during the testing period, but the model performed poorly for the third station (Nash-Sutcliffe coefficient only 0.44. Sensitivity analysis suggested that streamflow of upstream area of the watershed was dominated by slow groundwater, whilst streamflow of middle- and down- stream areas by relatively quick interflow. Therefore, a multi-site calibration protocol was deemed necessary. Due to the potential errors and uncertainties with respect to the representation of spatial variability, performance measures from the multi-site calibration protocol slightly decreased for two of the three stations, whereas it was improved greatly for the third station. We concluded that multi-site calibration protocol reached a compromise in term of model performance for the three stations, reasonably representing the hydrographs of all three stations with Nash-Sutcliffe coefficient ranging from 0.59–072. The multi-site calibration protocol applied in the analysis generally has advantages to the single site calibration protocol.

  10. Characterisation of the effect of ion channel modulators on I1-imidazoline binding sites in bovine adrenal medulla

    International Nuclear Information System (INIS)

    Musgrave, I.F.; Kotsopoulos, D.; Hughes, R.A.

    1998-01-01

    Full text: The structure of I 1 -imidazoline binding sites is still unknown and we have proposed that they represent ion channels (i). In these experiments we characterised the effects of the known ion channel modulators methyltriphenylphosphonium (MTPP), 4-aminopyridine (4-AP) and tetraethyl ammonium (TEA) on [ 3 H] clonidine binding in bovine adrenal medullary membranes as these membranes have a relatively well defined I 1 -imidazoline binding site (Molderings et al, 1993). Membranes from bovine adrenal medulla's were prepared by a minor modification of the method of Rapier et al. [ 3 H] Clonidine binding was performed by the method of Ernsberger et al (3), with [ 3 H] clonidine (62 Ci/mmol) used at a final concentration of 5 nM. [ 3 H] Clonidine binding was displaced from bovine adrenal medullary membranes by adrenergic drugs with the order of potency being oxymetazoline > clonidine > moxonidine = idazoxan >> yonimbine. This order of potency is consistent with previous studies of I 1 -imidazoline binding sites (4). Non-linear curve fitting to this data was consistent with a single site model. Both TEA and 4-AP displaced [ H] clonidine with similar potency to its effect on ion channels, TEA having a EC>> of 54 ± 0.3 μM (n=3). The displacement of [ 3 H] clonidine produced by both TEA and 4-AP also fitted to a single site model. Displacement of [ 3 H] clonidine by MTPP fitted a two site model (p 1 -imidazoline binding sites defined with [ 3 H] clonidine may represent ion channels. We have used this data to perform molecular modelling and have determined a common conformation of I 1 -prefering ligands which will aid in the development of I 1 -selective ligands in the future. Copyright (1998) Australian Neuroscience Society

  11. Does physical or psychosocial workload modify the effect of musculoskeletal pain on sickness absence? A prospective study among the Finnish population.

    Science.gov (United States)

    Neupane, Subas; Pensola, Tiina; Haukka, Eija; Ojajärvi, Anneli; Leino-Arjas, Päivi

    2016-07-01

    Previously, among food industry workers, multisite pain predicted sickness absence (SA) only in those with low biomechanical workload. Here we studied among a wide range of occupations whether the relationship of pain with SA was modified by the level of physical or psychosocial workload. A nationally representative sample (Health 2000 Survey) comprised 3420 occupationally active Finns aged 30-55 years. Baseline data on musculoskeletal pain during the preceding month, strenuous work history, current physical workload, job demands, job control, support at work, lifestyle, and chronic diseases were obtained in 2000/2001 by questionnaire, interview, and clinical examination. Musculoskeletal pain in 18 body locations was combined into four sites (neck, upper limbs, low back, and lower limbs) and classified as no pain, single-site pain, and multisite pain (2-4 sites). The data were linked with information from national registers on annual SA periods lasting ≥10 workdays for 2002-2008. Negative binomial regression analysis was used. At baseline, one-third of the study sample reported single-site and one-third multisite pain. Allowing for gender and age, the employees with multisite pain in strata with high physical workload and high job demands tended to have the highest risk of SA, but no statistically significant interactive effects between work factors and pain were observed. Further adjustment for health-related lifestyle and chronic diseases decreased the risk estimates in all strata. We did not find evidence for significant modification by physical or psychosocial workload of the relationship between musculoskeletal pain and SA periods lasting ≥10 workdays.

  12. Bipyridine- and phenanthroline-based metal-organic frameworks for highly efficient and tandem catalytic organic transformations via directed C-H activation

    Energy Technology Data Exchange (ETDEWEB)

    Manna, Kuntal [Univ. of Chicago, Chicago, IL (United States); Zhang, Teng [Univ. of Chicago, Chicago, IL (United States); Greene, Francis X. [Univ. of Chicago, Chicago, IL (United States); Lin, Wenbin [Univ. of Chicago, Chicago, IL (United States)

    2015-02-16

    We report here the synthesis of a series of robust and porous bipyridyl- and phenanthryl-based metal–organic frameworks (MOFs) of UiO topology (BPV-MOF, mBPV-MOF, and mPT-MOF) and their postsynthetic metalation to afford highly active single-site solid catalysts. While BPV-MOF was constructed from only bipyridyl-functionalized dicarboxylate linker, both mBPV- and mPT-MOF were built with a mixture of bipyridyl- or phenanthryl-functionalized and unfunctionalized dicarboxylate linkers. The postsynthetic metalation of these MOFs with [Ir(COD)(OMe)]2 provided Ir-functionalized MOFs (BPV-MOF-Ir, mBPV-MOF-Ir, and mPT-MOF-Ir), which are highly active catalysts for tandem hydrosilylation of aryl ketones and aldehydes followed by dehydrogenative ortho-silylation of benzylicsilyl ethers as well as C–H borylation of arenes using B₂pin₂. Both mBPV-MOF-Ir and mPT-MOF-Ir catalysts displayed superior activities compared to BPV-MOF-Ir due to the presence of larger open channels in the mixed-linker MOFs. Impressively, mBPV-MOF-Ir exhibited high TONs of up to 17000 for C–H borylation reactions and was recycled more than 15 times. The mPT-MOF-Ir system is also active in catalyzing tandem dehydrosilylation/dehydrogenative cyclization of N-methylbenzyl amines to azasilolanes in the absence of a hydrogen acceptor. Importantly, MOF-Ir catalysts are significantly more active (up to 95 times) and stable than their homogeneous counterparts for all three reactions, strongly supporting the beneficial effects of active site isolation within MOFs. This work illustrates the ability to increase MOF open channel sizes by using the mixed linker approach and shows the enormous potential of developing highly active and robust single-site solid catalysts based on MOFs containing nitrogen-donor ligands for important organic transformations.

  13. Staging of nasopharyngeal carcinoma investigated by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Lu Jincheng; Wei Baoqing; Chen Wenzhan; Qian Pudong; Zhang Yiqin; Wei Qing; Cha Wenwu; Li Feng; Ni Ming

    2006-01-01

    Background and purpose: To investigate the American Joint Commission on Cancer (AJCC) sixth edition staging system of nasopharyngeal carcinoma (NPC) by Magnetic Resonance Imaging (MRI). Patients and methods: One hundred and fifty-nine non-disseminated biopsy-proven NPC patients were studied with MRI before treatment. Retrieval of MRI information enabled us to restage all patients accurately according to the sixth edition of the AJCC staging system. Splitting the respective T and N stages by the significant defining factors identified, the cancer death hazard ratios were modeled by the Cox model in SPSS 10.0 for windows (SPSS Inc, Chicago, IL). Results: Single site of skull base abnormality (HR=3.91, 95% CI: 0.74-20.56) has a superior result to others involved in T3 (HR=5.83, 95% CI: 1.24-27.29). Involvement of either anterior or posterior cranial nerves solely (HR=6.02, 95% CI: 1.55-35.60) was not found to be as a poor prognostic indicator as others involved in T4 (HR=7.81, 95% CI: 1.81-33.63). Less than or equal to 3 cm of N1 (HR=4.01, 95% CI: 0.48-33.83) and N2 (HR=4.72, 95% CI: 0.62-35.78) have a better result than >3 cm of N1 (HR=8.09, 95% CI: 0.95-68.97) and N2 (HR=10.58, 95% CI: 1.32-84.62), respectively. Conclusions: Perhaps, it is better to down-stage single site of skull base abnormality from T3 to T2, and involvement of either anterior or posterior cranial nerves solely from T4 to T3, meanwhile, ≤3 cm of N2 down-stage to N1, >3 cm of N1 up-stage to N2

  14. A systematic review of the quality of homeopathic clinical trials

    Science.gov (United States)

    Jonas, Wayne B; Anderson, Rachel L; Crawford, Cindy C; Lyons, John S

    2001-01-01

    Background While a number of reviews of homeopathic clinical trials have been done, all have used methods dependent on allopathic diagnostic classifications foreign to homeopathic practice. In addition, no review has used established and validated quality criteria allowing direct comparison of the allopathic and homeopathic literature. Methods In a systematic review, we compared the quality of clinical-trial research in homeopathy to a sample of research on conventional therapies using a validated and system-neutral approach. All clinical trials on homeopathic treatments with parallel treatment groups published between 1945–1995 in English were selected. All were evaluated with an established set of 33 validity criteria previously validated on a broad range of health interventions across differing medical systems. Criteria covered statistical conclusion, internal, construct and external validity. Reliability of criteria application is greater than 0.95. Results 59 studies met the inclusion criteria. Of these, 79% were from peer-reviewed journals, 29% used a placebo control, 51% used random assignment, and 86% failed to consider potentially confounding variables. The main validity problems were in measurement where 96% did not report the proportion of subjects screened, and 64% did not report attrition rate. 17% of subjects dropped out in studies where this was reported. There was practically no replication of or overlap in the conditions studied and most studies were relatively small and done at a single-site. Compared to research on conventional therapies the overall quality of studies in homeopathy was worse and only slightly improved in more recent years. Conclusions Clinical homeopathic research is clearly in its infancy with most studies using poor sampling and measurement techniques, few subjects, single sites and no replication. Many of these problems are correctable even within a "holistic" paradigm given sufficient research expertise, support and methods

  15. Patterns and Timing of Initial Relapse in Patients Subsequently Undergoing Transplantation for Hodgkin's Lymphoma

    International Nuclear Information System (INIS)

    Dhakal, Sughosh; Biswas, Tithi; Liesveld, Jane L.; Friedberg, Jonathan W.; Phillips, Gordon L.; Constine, Louis S.

    2009-01-01

    Purpose: To evaluate the patterns and timing of initial recurrence in patients with Hodgkin's lymphoma (HL) who subsequently underwent high-dose chemotherapy with autologous stem cell transplantation to enhance our understanding of the natural history of this disease and its modern treatment strategies and to direct approaches to disease surveillance. Methods and Materials: The records of 69 patients with HL who had undergone high-dose chemotherapy with autologous stem cell transplantation in our center between May 1992 and June 2006 were analyzed. The initial diagnosis had been made between April 1982 and January 2005 at a median patient age of 33 years (range, 19-65). The patients were segregated according to the initial stage (Stage I-II vs. III-IV). Results: Early-stage HL patients developed a relapse at a median of 2.1 years (range, 0.5-10.3), with 91% of relapses at the initial disease site, 71% of which (65% overall) were only in previously involved sites. Advanced-stage HL patients developed a relapse at a median of 1.5 years (range, 0.6-10.5), with 97% at the initial site, 71% of which (69% overall) were only in previously involved sites. Single-site relapses occurred in 47% of early- vs. 26% of advanced-stage patients, and extranodal relapses occurred in 12% of early- vs. 31% of advanced-stage patients. Conclusions: Almost all patients with HL who develop relapse and subsequently undergo high-dose chemotherapy with autologous stem cell transplantation initially developed recurrence in previously involved disease sites. Early-stage HL relapses often occurred in single sites, and advanced-stage disease relapses were more likely in multiple and extranodal sites. The interval to recurrence was brief, suggesting that the frequency of screening should be the greatest in the early post-therapy years.

  16. Current Research Status of KHNP for Site Risk

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Kyemin; Jeon, Ho-Jun; Bahng, Ki-In; Na, Jang-Hwan [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    In Korea, by the geographical characteristics, many Nuclear Power Plants (NPPs) have been constructed and operated at a single site. This is above average level or number of plants per site in the world. For this reason, the public concerns for the safety of nuclear facilities increased after Fukushima Daiichi accident. As a result, comprehensive risk assessment and management for the site which have multi-unit NPPs were strongly asked. Currently, to solve it, many researches and projects has carried out by various Korean companies, research centers, and regulatory authorities. In this paper, R and D plans of KHNP for multi-unit risk were summarized. Firstly, the needs of multi-unit PSA were reviewed. R and D activities and plans of KHNP were summarized in the last part. In this paper, we summarized the R and D plans of KHNP for assessing the multi-unit risk. Currently, multi-unit risk or multi-unit PSA are important and practical issues in both nuclear industry and national energy policy. After Fukushima accident, several countries stopped the construction and the operation of NPPs, other countries which is maintaining the NPPs are being strongly asked to assess the risk for multi-unit NPPs at the same site. Because of Korean geographical characteristics, the number of NPPs which are above average level or number of plants per site in the world is being constructed and operated at a single site. The population density nearby each site is considered to be higher than that of other countries.

  17. Current Research Status of KHNP for Site Risk

    International Nuclear Information System (INIS)

    Oh, Kyemin; Jeon, Ho-Jun; Bahng, Ki-In; Na, Jang-Hwan

    2016-01-01

    In Korea, by the geographical characteristics, many Nuclear Power Plants (NPPs) have been constructed and operated at a single site. This is above average level or number of plants per site in the world. For this reason, the public concerns for the safety of nuclear facilities increased after Fukushima Daiichi accident. As a result, comprehensive risk assessment and management for the site which have multi-unit NPPs were strongly asked. Currently, to solve it, many researches and projects has carried out by various Korean companies, research centers, and regulatory authorities. In this paper, R and D plans of KHNP for multi-unit risk were summarized. Firstly, the needs of multi-unit PSA were reviewed. R and D activities and plans of KHNP were summarized in the last part. In this paper, we summarized the R and D plans of KHNP for assessing the multi-unit risk. Currently, multi-unit risk or multi-unit PSA are important and practical issues in both nuclear industry and national energy policy. After Fukushima accident, several countries stopped the construction and the operation of NPPs, other countries which is maintaining the NPPs are being strongly asked to assess the risk for multi-unit NPPs at the same site. Because of Korean geographical characteristics, the number of NPPs which are above average level or number of plants per site in the world is being constructed and operated at a single site. The population density nearby each site is considered to be higher than that of other countries

  18. Eu3+-doped β-Ga2O3 nanophosphors: annealing effect, electronic structure and optical spectroscopy.

    Science.gov (United States)

    Zhu, Haomiao; Li, Renfu; Luo, Wenqin; Chen, Xueyuan

    2011-03-14

    A comprehensive survey of electronic structure and optical properties of rare-earth ions-doped semiconductor is of vital importance for their potential applications. In this work, Eu(3+)-doped β-Ga(2)O(3) nanocrystals were synthesized via a combustion method. The evolution of the optical properties of nanophosphors with increasing the annealing temperature was investigated in detail by means of excitation and emission spectra at room temperature and 10 K. Eu(3+) ions were proved to be incorporated into the crystal lattice of the β-Ga(2)O(3) phase after annealing the as-prepared nanoparticles at 1100 °C. It was observed that the substitution of Eu(3+) for Ga(3+) occurred at merely single site, in spite of two crystallographically nonequivalent sites of Ga(3+) in β-Ga(2)O(3). Spectroscopic evidence corroborated and clarified the local symmetry of C(s) for Eu(3+) at this single site. From the high-resolution excitation and emission spectra, 71 crystal-field levels of Eu(3+) in β-Ga(2)O(3) were identified and analyzed in terms of 19 freely varied free-ions and crystal-field parameters based on C(s) symmetry. The standard deviation of the final fitting is as low as 12.9 cm(-1), indicating an excellent agreement between experimental and calculated energy levels. The temperature-dependent luminescence dynamics of the (5)D(0) multiplet for Eu(3+) in β-Ga(2)O(3) phosphors has also been revealed for the first time from 10 to 300 K.

  19. Theoretical Evaluation of Electromagnetic Emissions from GSM900 Mobile Telephony Base Stations in the West Bank and Gaza Strip-Palestine.

    Science.gov (United States)

    Lahham, Adnan; Alkbash, Jehad Abu; ALMasri, Hussien

    2017-04-20

    Theoretical assessments of power density in far-field conditions were used to evaluate the levels of environmental electromagnetic frequencies from selected GSM900 macrocell base stations in the West Bank and Gaza Strip. Assessments were based on calculating the power densities using commercially available software (RF-Map from Telstra Research Laboratories-Australia). Calculations were carried out for single base stations with multiantenna systems and also for multiple base stations with multiantenna systems at 1.7 m above the ground level. More than 100 power density levels were calculated at different locations around the investigated base stations. These locations include areas accessible to the general public (schools, parks, residential areas, streets and areas around kindergartens). The maximum calculated electromagnetic emission level resulted from a single site was 0.413 μW cm-2 and found at Hizma town near Jerusalem. Average maximum power density from all single sites was 0.16 μW cm-2. The results of all calculated power density levels in 100 locations distributed over the West Bank and Gaza were nearly normally distributed with a peak value of ~0.01% of the International Commission on Non-Ionizing Radiation Protection's limit recommended for general public. Comparison between calculated and experimentally measured value of maximum power density from a base station showed that calculations overestimate the actual measured power density by ~27%. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Eu/RG absorption and excitation spectroscopy in the solid rare gases: state dependence of crystal field splitting and Jahn-Teller coupling.

    Science.gov (United States)

    Byrne, Owen; McCaffrey, John G

    2011-03-28

    Absorption spectroscopy recorded for annealed samples of matrix-isolated atomic europium reveals a pair of thermally stable sites in Ar and Kr while a single site exists in Xe. Plots of the matrix shifts of the visible s → p bands versus host polarizability, allowed the association of the single site in Xe and the blue sites in Ar and Kr. On the basis of the similar ground state bond lengths expected for the Eu-rare gas (RG) diatomics and the known Na-RG molecules, the blue sites are attributed to Eu occupancy in the smaller tetra-vacancy while the red sites are proposed to arise from hexa-vacancy sites. Both sites are of cubic symmetry, consistent with the pronounced Jahn-Teller structure present on the y(8)P ← a(8)S(7/2) transition for these bands in the three hosts studied. Site-selective excitation spectroscopy has been used to reanalyze complex absorption spectra previously published by Jakob et al. [Phys. Lett. A 57, 67 (1976)] for the near-UV f → d transitions. On the basis that a pair of thermally stable sites exist in solid argon, the occurrence of crystal field splitting has been identified to occur for the J ≥ 5/2 level of the (8)P state when isolated in these two sites with cubic symmetry. From a detailed lineshape analysis, the magnitude of the crystal field splittings on the J = 5/2 level in Ar is found to be 105 and 123 cm(-1) for the red and blue sites, respectively.