Complications of transvaginal natural orifice transluminal endoscopic surgery: a series of 102 patients.

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Wood, Stephanie G; Panait, Lucian; Duffy, Andrew J; Bell, Robert L; Roberts, Kurt E

2014-04-01

To review the complications encountered in our facility and in previously published studies of transvaginal (TV) natural orifice transluminal endoscopic surgery (NOTES) to date. TV NOTES is currently observed with critical eyes from the surgical community, despite encouraging data to suggest improved short-term recovery and pain. All TV NOTES procedures performed in female patients between 18 and 65 years of age were included. The median follow-up was 90 days. The TV appendectomies and ventral hernia repairs were pure NOTES, through a SILS port in the vagina, whereas TV cholecystectomies were hybrid procedures with the addition of a 5-mm port in the umbilicus. A total of 102 TV NOTES procedures, including 72 TV cholecystectomies, 24 TV appendectomies, and 6 TV ventral hernia repairs, were performed. The average age was 37 years old and body mass index was 29 kg/m. Three major and 7 minor complications occurred. The first major complication was a rectal injury during a TV access port insertion. The second major complication was an omental vessel bleed after a TV cholecystectomy. The third complication was an intra-abdominal abscess after a TV appendectomy. Seven minor complications were urinary retention (4), transient brachial plexus injury, dislodgement of an intrauterine device, and vaginal granulation tissue. As techniques in TV surgery are adopted, inevitably, complications may occur due to the inherent learning curve. Laparoscopic instruments, although adaptable to TV approaches, have yet to be optimized. A high index of suspicion is necessary to identify complications and optimize outcomes for patients.

Natural orifice transluminal endoscopic surgery for patients with perforated peptic ulcer.

Science.gov (United States)

Bonin, Eduardo A; Moran, Erica; Gostout, Christopher J; McConico, Andrea L; Zielinski, Martin; Bingener, Juliane

2012-06-01

Perforation accounts for 70% of deaths attributed to peptic ulcers. Laparoscopic repair is effective but infrequently used. Our aim was to assess how many patients with perforated peptic ulcer could be candidates for a transluminal endoscopic omental patch closure. This retrospective study reviewed patients with perforated peptic ulcer from 2005 to 2010. Demographics, ulcer characteristics, operative procedure, and outcomes were recorded. Candidates for endoscopic transluminal repair were defined as those having undergone omental patch closure of an ulcer of appropriate size and no contraindications to laparoscopy or endoscopy. In the retrospective review, a total of 104 patients were identified; 62% female, mean age = 68 years, mean ASA of 3, and 63% medication-related ulcers. Fifty-nine (63%) had an omental patch (80% open), and 35 (37%) had other procedures. Ten patients had nonoperative management. Thirty-day mortality was 14% and 1 year mortality was 35%. Forty-nine patients (52%) were considered potential candidates for transluminal repair. Sixty-three percent of our patients sustained a medication-related perforation with 1 year mortality of 35%. The majority of patients were treated using open omental patch repair. Transluminal endoscopic repair may provide an additional situation for a minimally invasive approach for a number of these patients.

A novel semi-automatic snake robot for natural orifice transluminal endoscopic surgery: preclinical tests in animal and human cadaver models (with video).

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Son, Jaebum; Cho, Chang Nho; Kim, Kwang Gi; Chang, Tae Young; Jung, Hyunchul; Kim, Sung Chun; Kim, Min-Tae; Yang, Nari; Kim, Tae-Yun; Sohn, Dae Kyung

2015-06-01

Natural orifice transluminal endoscopic surgery (NOTES) is an emerging surgical technique. We aimed to design, create, and evaluate a new semi-automatic snake robot for NOTES. The snake robot employs the characteristics of both a manual endoscope and a multi-segment snake robot. This robot is inserted and retracted manually, like a classical endoscope, while its shape is controlled using embedded robot technology. The feasibility of a prototype robot for NOTES was evaluated in animals and human cadavers. The transverse stiffness and maneuverability of the snake robot appeared satisfactory. It could be advanced through the anus as far as the peritoneal cavity without any injury to adjacent organs. Preclinical tests showed that the device could navigate the peritoneal cavity. The snake robot has advantages of high transverse force and intuitive control. This new robot may be clinically superior to conventional tools for transanal NOTES.

Comparison of pain and postoperative stress in dogs undergoing natural orifice transluminal endoscopic surgery, laparoscopic, and open oophorectomy.

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Freeman, Lynetta J; Rahmani, Emad Y; Al-Haddad, Mohammad; Sherman, Stuart; Chiorean, Michael V; Selzer, Don J; Snyder, Paul W; Constable, Peter D

2010-08-01

Few studies are available to compare the potential benefits of natural orifice transluminal endoscopic surgery (NOTES) approaches to traditional surgery. To compare complications, surgical stress, and postoperative pain. Prospective study in dogs. Research laboratory. Thirty dogs. Oophorectomy procedures were performed via NOTES and laparoscopic and traditional open surgery. Operative time, pain scores, systemic stress parameters (cortisol, glucose), surgical stress markers (interleukin 6, C-reactive protein), 3-day observation. Median operative times were 76, 44, and 35 minutes for the NOTES, laparoscopic, and open procedures, respectively, with the NOTES procedure being significantly longer than the other 2 procedures. All ovaries were completely excised, and all the animals survived without complications. The NOTES animals had greater increases in serum cortisol concentrations at 2 hours but no statistically significant differences in glucose concentrations compared with the other groups. Serum interleukin 6 and C-reactive protein concentrations were significantly increased at specific times compared with baseline in the NOTES group, but not in the open or laparoscopic surgery groups. Based on the cumulative pain score and nociceptive thresholds, the animals in the NOTES group demonstrated less evidence of pain. Small sample size, limited follow-up. Although the NOTES oophorectomy procedures took approximately twice as long and there may be more evidence of tissue damage as judged by increases in serum cortisol and interleukin 6 concentrations, the dogs in the NOTES group had lower pain scores, especially when compared with animals undergoing open surgery. Copyright 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

Natural orifice transgastric endoscopic wedge hepatic resection in an experimental model using an intuitively controlled master and slave transluminal endoscopic robot (MASTER).

Science.gov (United States)

Phee, S J; Ho, K Y; Lomanto, D; Low, S C; Huynh, V A; Kencana, A P; Yang, K; Sun, Z L; Chung, S C Sydney

2010-09-01

The lack of triangulation of standard endoscopic devices limits the degree of freedom for surgical maneuvers during natural orifice transluminal endoscopic surgery (NOTES). This study explored the feasibility of adapting an intuitively controlled master and slave transluminal endoscopic robot (MASTER) the authors developed to facilitate wedge hepatic resection in NOTES. The MASTER consists of a master controller, a telesurgical workstation, and a slave manipulator that holds two end-effectors: a grasper, and a monopolar electrocautery hook. The master controller is attached to the wrist and fingers of the operator and connected to the manipulator by electrical and wire cables. Movements of the operator are detected and converted into control signals driving the slave manipulator via a tendon-sheath power transmission mechanism allowing nine degrees of freedom. Using this system, wedge hepatic resection was performed through the transgastric route on two female pigs under general anesthesia. Entry into the peritoneal cavity was via a 10-mm incision made on the anterior wall of the stomach by the electrocautery hook. Wedge hepatic resection was performed using the robotic grasper and hook. Hemostasis was achieved with the electrocautery hook. After the procedure, the resected liver tissue was retrieved through the mouth using the grasper. Using the MASTER, transgastric wedge hepatic resection was successfully performed on two pigs with no laparoscopic assistance. The entire procedure took 9.4 min (range, 8.5-10.2 min), with 7.1 min (range, 6-8.2 min) spent on excision of the liver tissue. The robotics-controlled device was able to grasp, retract, and excise the liver specimen successfully in the desired plane. This study demonstrated for the first time that the MASTER could effectively mitigate the technical constraints normally encountered in NOTES procedures. With it, the triangulation of surgical tools and the manipulation of tissue became easy, and wedge hepatic

Surgery via natural orifices in human beings: yesterday, today, tomorrow.

Science.gov (United States)

Moris, Demetrios N; Bramis, Konstantinos J; Mantonakis, Eleftherios I; Papalampros, Efstathios L; Petrou, Athanasios S; Papalampros, Alexandros E

2012-07-01

We performed an evaluation of models, techniques, and applicability to the clinical setting of natural orifice surgery (mainly natural orifice transluminal endoscopic surgery [NOTES]) primarily in general surgery procedures. NOTES has attracted much attention recently for its potential to establish a completely alternative approach to the traditional surgical procedures performed entirely through a natural orifice. Beyond the potentially scar-free surgery and abolishment of dermal incision-related complications, the safety and efficacy of this new surgical technology must be evaluated. Studies were identified by searching MEDLINE, EMBASE, Cochrane Library, and Entrez PubMed from 2007 to February 2011. Most of the references were identified from 2009 to 2010. There were limitations as far as the population that was evaluated (only human beings, no cadavers or animals) was concerned, but there were no limitations concerning the level of evidence of the studies that were evaluated. The studies that were deemed applicable for our review were published mainly from 2007 to 2010 (see Methods section). All the evaluated studies were conducted only in human beings. We studied the most common referred in the literature orifices such as vaginal, oral, gastric, esophageal, anal, or urethral. The optimal access route and method could not be established because of the different nature of each procedure. We mainly studied procedures in the field of general surgery such as cholecystectomy, intestinal cancers, renal cancers, appendectomy, mediastinoscopy, and peritoneoscopy. All procedures were feasible and most of them had an uneventful postoperative course. A number of technical problems were encountered, especially as far as pure NOTES procedures are concerned, which makes the need of developing new endoscopic instruments, to facilitate each approach, undeniable. NOTES is still in the early stages of development and more robust technologies will be needed to achieve reliable

Natural orifice transluminal endoscopic surgery gastrotomy closure with an over-the-endoscope clip: a randomized, controlled porcine study (with videos).

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von Renteln, Daniel; Schmidt, Arthur; Vassiliou, Melina C; Gieselmann, Maria; Caca, Karel

2009-10-01

Secure endoscopic closure of transgastric natural orifice transluminal endoscopic surgery (NOTES) access is of paramount importance. The over-the-scope clip (OTSC) system has previously been shown to be effective for NOTES gastrotomy closure. To compare OTSC gastrotomy closure with surgical closure. Randomized, controlled animal study. Animal facility laboratory. Thirty-six female domestic pigs. Gastrotomies were created by using a needle-knife and an 18-mm balloon. The animals were subsequently randomized to either open surgical repair with interrupted sutures or endoscopic repair with 12-mm OTSCs. In addition, pressurized leak tests were performed in ex vivo specimens of 18-mm scalpel incisions closed with suture (n = 14) and of intact stomachs (n = 10). The mean time for endoscopic closure was 9.8 minutes (range 3-22, SD 5.5). No complications occurred during either type of gastrotomy closure. At necropsy, examination of all OTSC and surgical closures demonstrated complete sealing of gastrotomy sites without evidence of injury to adjacent organs. Pressurized leak tests showed a mean burst pressure of 83 mm Hg (range 30-140, SD 27) for OTSC closures and 67 mm Hg (range 30-130, SD 27.7) for surgical sutures. Ex vivo hand-sewn sutures of 18-mm gastrotomies (n = 14) exhibited a mean burst pressure of 65 mm Hg (range 20-140, SD 31) and intact ex vivo stomachs (n = 10) had a mean burst pressure of 126 mm Hg (range 90-170, SD 28). The burst pressure of ex vivo intact stomachs was significantly higher compared with OTSC closures (P < .01), in vivo surgical closures (P < .01), and ex vivo hand-sewn closures (P < .01). There was a trend toward higher burst pressures in the OTSC closures compared with surgical closures (P = .063) and ex vivo hand-sewn closures (P = .094). In vivo surgical closures demonstrated similar burst pressures compared with ex vivo hand-sewn closures (P = .848). Nonsurvival setting. Endoscopic closure by using the OTSC system is comparable to

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

Directory of Open Access Journals (Sweden)

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.

Natural orifice translumenal endoscopic surgery (NOTES) for innovation in hepatobiliary and pancreatic surgery: preface.

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Sugimoto, Maki

2009-01-01

Natural orifice translumenal endoscopic surgery (NOTES) has captured the interest of interventional endoscopists and may represent the next stage of evolution of minimally invasive surgery. It provides the potential for performance of incisionless operations. It is gaining momentum both in the animal laboratory and in human case reports. Developments in the field of NOTES have led to the formation of the Natural Orifice Surgery Consortium for Assessment and Research (NOSCAR) in 2006. In this special issue, the current trends in NOTES in the field of hepatobiliary and pancreatic surgery are featured, including NOTES cholecystectomy, hepatectomy splenectomy, pancreatic necrosectomy, and the future of NOTES. In this issue, we discuss the potential benefits of these procedures in hepatobiliary and pancreatic surgery. We have just started the evaluation process for this new technology. The concept of NOTES is becoming established and is enormously advantageous for the patient. Both the surgeon and gastroenterologist should contribute to developing NOTES in making use of their specialties.

Laparoscopic sleeve gastrectomy for morbid obesity with natural orifice specimen extraction (NOSE).

Science.gov (United States)

Gunkova, P; Gunka, I; Zonca, P; Dostalik, J; Ihnat, P

2015-01-01

An experience with laparoscopic sleeve gastrectomy using the natural orifice specimen extraction (NOSE) technique. Bariatric surgery is nowadays the only long term effective obesity treatment method. Twenty one consecutive patients underwent laparoscopic sleeve gastrectomy with the use of natural orifice specimen extraction (NOSE) in the Surgical Clinic of Faculty Hospital Ostrava between May 2012 and August 2012. Inclusion criteria were the body mass index (BMI) higher than 35 kg/m2 or higher than 32 kg/m2 accompanied with relevant comorbidities. Among 21 patients in this series, there were three men (14.3%) and 18 women (85.7%). Their mean age was 40.9±10.2 years. Their mean preoperative BMI was 40.4±4.6 kg/m2. No patient had previous bariatric surgery, one patient had laparoscopic fundoplication. All operations were completed laparoscopically with no conversions to an open procedure. In two cases, laparoscopic cholecystectomy was performed and the gallbladder was extracted along with the gastric specimen by transgastric approach. Laparoscopic sleeve gastrectomy is a safe and effective bariatric procedure with low morbidity and mortality. Based on our initial experiences it could be an indication for NOSE with transgastric approach. Obese patients would benefit from this approach due to the elimination of wound complications (Tab. 2, Fig. 3, Ref. 22).

International Conference on Natural Orifice Transluminal Endoscopic Surgery (NOTES)

Science.gov (United States)

2006-06-01

hemangiomas, and one simple cyst), five were malignant in five patients (five hepatocarcinoma ). and four patients had an uncertain preoperative diagnosis...In the first three cases [ hepatocarcinoma (HCO of segment II, hydatid cyst of segment VI. and hemangioma of segment II], we used the Kellyclasia...HCC HCC HCC HCC HCC Hemangiomab l-’NH vs adenoma FNH vs adenoma FNH vs adenoma FHN. focal nodular hyperplasia; HCC, hepatocarcinoma 1

Do Basic Psychomotor Skills Transfer Between Different Image-based Procedures?

NARCIS (Netherlands)

Buzink, S.N.; Goossens, R.H.M.; Schoon, E.J.; De Ridder, H.; Jakimowicz, J.J.

2010-01-01

Background - Surgical techniques that draw from multiple types of image-based procedures (IBP) are increasing, such as Natural Orifice Transluminal Endoscopic Surgery, fusing laparoscopy and flexible endoscopy. However, little is known about the relation between psychomotor skills for performing

Randomized, blinded comparison of transgastric, transcolonic, and laparoscopic peritoneoscopy for the detection of peritoneal metastases in a human cadaver model

NARCIS (Netherlands)

Voermans, Rogier P.; Henegouwen, Mark I. van Berge; Cuba, Erienne de; Broek, Frank J. C. van den; van Acker, Gijs; Timmer, Robin; Fockens, Paul

2010-01-01

Background: Natural orifice transluminal endoscopic surgery peritoneoscopy may be able to replace laparoscopic peritoneoscopy (LAP) for staging of GI malignancies if it is proven to be equally accurate and safe. Objective: To compare transgastric peritoneoscopy (TGP) and transcolonic peritoneoscopy

Two cases of laparoscopic total colectomy with natural orifice specimen extraction and review of the literature.

Science.gov (United States)

Gundogan, Ersin; Aktas, Aydin; Kayaalp, Cuneyt; Gonultas, Fatih; Sumer, Fatih

2017-09-01

We present two cases of natural orifice specimen extraction (NOSE) after laparoscopic total colectomy and ileorectal anastomosis (TC-IRA), and we also review all of the previously reported cases. Our aim was to focus on patient selection for NOSE after TC-IRA. The PubMed and Google Scholar databases were scanned. Demographic features, surgical indications, and techniques were analyzed. Basic calculations were used for statistical analysis. A total of 13 cases were detected in addition to our 2 cases. All of the specimens were removed through the natural orifices successfully. No case required a diverting ileostomy. No patients were converted to open surgery or to conventional laparoscopy. Complications were reported in three patients. Transanal extractions were performed in 12 cases (10 colonic inertia, 2 polyposis), and transvaginal extractions were performed in 3 cases (2 malignancy, 1 colonic inertia). Both transanal and transvaginal specimen extractions after laparoscopic TC-IRA can be preferred. However, transanal extraction seems to be feasible in cases of TC for benign disease with a limited mesenteric-omental resection. If the indication is a malignancy requiring a mesenteric-omental resection, a transvaginal route should be preferred for a voluminous specimen.

The German registry for natural orifice translumenal endoscopic surgery: report of the first 551 patients.

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Lehmann, Kai S; Ritz, Jörg P; Wibmer, Andreas; Gellert, Klaus; Zornig, Carsten; Burghardt, Jens; Büsing, Martin; Runkel, Norbert; Kohlhaw, Kay; Albrecht, Roland; Kirchner, Tom G; Arlt, Georg; Mall, Julian W; Butters, Michael; Bulian, Dirk R; Bretschneider, Jörgen; Holmer, Christoph; Buhr, Heinz J

2010-08-01

To analyze patient outcome in the first 14 months of the German natural orifice translumenal endoscopic surgery (NOTES) registry (GNR). NOTES is a new surgical concept, which permits scarless intra-abdominal operations through natural orifices, such as the mouth, vagina, rectum, or urethra. The GNR was established as a nationwide outcome database to allow the monitoring and safe introduction of this technique in Germany. The GNR was designed as a voluntary database with online access. All surgeons in Germany who performed NOTES procedures were requested to participate in the registry. The GNR recorded demographical and therapy data as well as data on the postoperative course. A total of 572 target organs were operated in 551 patients. Cholecystectomies accounted for 85.3% of all NOTES procedures. All procedures were performed in female patients using transvaginal hybrid technique. Complications occurred in 3.1% of all patients, conversions to laparoscopy or open surgery in 4.9%. In cholecystectomies, institutional case volume, obesity, and age had substantial effect on conversion rate, operation length, and length of hospital stay, but no effect on complications. Despite the fact that NOTES has just recently been introduced, the technique has already gained considerable clinical application. Transvaginal hybrid NOTES cholecystectomy is a practicable and safe alternative to laparoscopic resection even in obese or older patients.

Effect of mitral orifice shape on intra-ventricular filling fluid dynamics

Science.gov (United States)

Okafor, Ikechukwu; Angirish, Yagna; Yoganathan, Ajit; Santhanakrishnan, Arvind

2013-11-01

The natural geometry of the mitral orifice is D-shaped. However, most current designs of prosthetic valves employ O-shaped orifice geometry. The goal of this study was to compare the effect of geometrical modification between the D and O orifice on the intra-ventricular fluid dynamics during diastolic filling. The different mitral orifice geometries were incorporated into an in vitro left heart simulator consisting of a flexible-walled anatomical left ventricle (LV) physical model enclosed in an acrylic housing. Physiological flow rates and pressures were obtained via tuning systemic resistance and compliance elements in the flow loop. A programmable piston pump was used to generate the LV model wall motion. 2D Particle image velocimetry measurements were conducted along multiple longitudinal planes perpendicular to the annulus plane. During peak diastole, the incoming jet width at the LV central plane was smaller for the D-orifice than that of the O-orifice. Further, the core of the vortex ring in the D-orifice was reduced in size compared to that of the O-orifice. The spatiotemporal spreading of the inflow jet as well as the propagation of the vortex ring will be discussed. This study was funded by a grant from the National Heart, Lung and Blood Institute (RO1HL70262).

Percutaneous transluminal coronary angioplasty

International Nuclear Information System (INIS)

Przybojewski, J.Z.; Weich, H.F.H.

1984-01-01

The purpose of this article is to review PTCA, percutaneous transluminal coronary angioplasty, which can be considered to be a truly revolutionary and fairly simple invasive form of intervention to atherosclerotic obstruction. The 'epidemic' of IHD, ischaemic heart disease, in the Republic of South Africa calls for the employment of this technique, which has already been carried out in a few teaching hospitals in this country. Very recently, modified balloon dilatation catheters have been used percutaneously in the non-operative transluminal correction of congenital coarctation of the aorta in infants and children, congenital pulmonary value stenosis, and hypoplasia and stenosis of the pulmonary arteries. It has also been employed for PTCA and for the simultaneous occlusion of coronary-bronchial artery anastomosis using a detachable balloon. The isotopes thallium 201 and technetium 99 were also used in scintiscanning

Single loop-and-clips technique (KING closure) for gastrotomy closure after transgastric ovariectomy: a survival experiment

Czech Academy of Sciences Publication Activity Database

Ryska, O.; Martinek, J.; Filípková, T.; Doležel, R.; Juhásová, Jana; Motlík, Jan; Zavoral, M.; Ryska, M.

2012-01-01

Roč. 7, č. 4 (2012), s. 233-239 ISSN 1895-4588 R&D Projects: GA MZd NS9994 Institutional research plan: CEZ:AV0Z50450515 Keywords : natural orifice transluminal endoscopic surgery * gastric closure * clips * endoloop Subject RIV: FJ - Surgery incl. Transplants Impact factor: 0.757, year: 2012

Percutaneous transluminal angioplasty of the carotid artery

International Nuclear Information System (INIS)

Numaguchi, Y.; Tulane Univ., New Orleans, LA; Puyau, F.A.; Provenza, L.J.; Richardson, D.E.

1984-01-01

The successful dilatation of postsurgical concentric stenosis of an internal carotid artery using percutaneous transluminal angioplasty (PTA) is reported here. Only one such case has been previously documented. Review of the literature disclosed 16 patients who received transluminal angioplasty for stenosis of carotid arteries by percutaneous or open arteriotomy techniques. The authors feel that PTA may be the treatment of choice for postoperative concentric stenosis of a short segment of the carotid artery as opposed to surgical repair. (orig.)

Development of a Virtual Reality Simulator for Natural Orifice Translumenal Endoscopic Surgery (NOTES) Cholecystectomy Procedure.

Science.gov (United States)

Ahn, Woojin; Dargar, Saurabh; Halic, Tansel; Lee, Jason; Li, Baichun; Pan, Junjun; Sankaranarayanan, Ganesh; Roberts, Kurt; De, Suvranu

2014-01-01

The first virtual-reality-based simulator for Natural Orifice Translumenal Endoscopic Surgery (NOTES) is developed called the Virtual Translumenal Endoscopic Surgery Trainer (VTESTTM). VTESTTM aims to simulate hybrid NOTES cholecystectomy procedure using a rigid scope inserted through the vaginal port. The hardware interface is designed for accurate motion tracking of the scope and laparoscopic instruments to reproduce the unique hand-eye coordination. The haptic-enabled multimodal interactive simulation includes exposing the Calot's triangle and detaching the gall bladder while performing electrosurgery. The developed VTESTTM was demonstrated and validated at NOSCAR 2013.

Endoscopic management of intraoperative small bowel laceration during natural orifice translumenal endoscopic surgery: a blinded porcine study.

Science.gov (United States)

Fyock, Christopher J; Forsmark, Chris E; Wagh, Mihir S

2011-01-01

Natural orifice translumenal endoscopic surgery (NOTES) has recently gained great enthusiasm, but there is concern regarding the ability to endoscopically manage complications purely via natural orifices. To assess the feasibility of endoscopically managing enteral perforation during NOTES using currently available endoscopic accessories. Twelve pigs underwent transgastric or transcolonic endoscopic exploration. Full-thickness enterotomies were intentionally created to mimic accidental small bowel lacerations during NOTES. These lacerations were then closed with endoclips. In the blinded arm of the study, small bowel repair was performed by a second blinded endoscopist. Adequate closure of the laceration was confirmed with a leak test. Primary access sites were closed with endoclips or T-anchors. At necropsy, the peritoneal cavity was inspected for abscesses, bleeding, or damage to surrounding structures. The enterotomy site was examined for adequacy of closure, adhesions, or evidence of infection. Fifteen small bowel lacerations were performed in 12 animals. Successful closure was achieved in all 10 cases in the nonblinded arm. Survival animals had an uncomplicated postoperative course and all enterotomy sites were well healed without evidence of necrosis, adhesions, abscess, or bleeding at necropsy. Leak test was negative in all animals. In the blinded arm, both small intestinal lacerations could not be identified by the blinded endoscopist. Necropsy revealed open small bowel lacerations. Small intestinal injuries are difficult to localize with currently available flexible endoscopes and accessories. Endoscopic clips, however, may be adequate for closure of small bowel lacerations if the site of injury is known.

Subclavian steal syndrome: treatment by percutaneous transluminal angioplasty

International Nuclear Information System (INIS)

Abath, Carlos Gustavo Coutinho; Silva, Marcos Antonio Barbosa da; Brito, Norma Maria Tenorio; Marques, Silvio Romero; Santa Cruz, Rodolfo

1995-01-01

The subclavian steal syndrome is a rare vascular disease that can be managed by interventional radiology. It is presented the experience with three cases of this syndrome that underwent percutaneous transluminal angioplasty, and a brief literature review is done. Two patients remained asymptomatic 23 and 30 months, respectively, after the procedure. One patient presented with recurrent symptoms 12 months after the dilatation. Considering the low morbidity and good clinical and technical results, percutaneous transluminal angioplasty is the first choice in the subclavian steal syndrome treatment. (author). 9 refs., 3 figs

The penetration of aerosols through fine orifices

International Nuclear Information System (INIS)

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

1991-07-01

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

High Pressure Water Stripping Using Multi-Orifice Nozzles

Science.gov (United States)

Hoppe, David

1999-01-01

The use of multi-orifice rotary nozzles greatly increases the speed and stripping effectiveness of high pressure water blasting systems, but also greatly increases the complexity of selecting and optimizing the operating parameters. The rotational speed of the nozzle must be coupled with its transverse velocity as it passes across the surface of the substrate being stripped. The radial and angular positions of each orifice must be included in the analysis of the nozzle configuration. Orifices at the outer edge of the nozzle head move at a faster rate than the orifices located near the center. The energy transmitted to the surface from the impact force of the water stream from an outer orifice is therefore spread over a larger area than energy from an inner orifice. Utilizing a larger diameter orifice in the outer radial positions increases the total energy transmitted from the outer orifice to compensate for the wider distribution of energy. The total flow rate from the combination of all orifices must be monitored and should be kept below the pump capacity while choosing orifice to insert in each position. The energy distribution from the orifice pattern is further complicated since the rotary path of all the orifices in the nozzle head pass through the center section. All orifices contribute to the stripping in the center of the path while only the outer most orifice contributes to the stripping at the edge of the nozzle. Additional orifices contribute to the stripping from the outer edge toward the center section. With all these parameters to configure and each parameter change affecting the others, a computer model was developed to track and coordinate these parameters. The computer simulation graphically indicates the cumulative affect from each parameter selected. The result from the proper choices in parameters is a well designed, highly efficient stripping system. A poorly chosen set of parameters will cause the nozzle to strip aggressively in some areas

Natural orifice translumenal endoscopic surgery: Progress in humans since white paper

Institute of Scientific and Technical Information of China (English)

Byron F Santos; Eric S Hungness

2011-01-01

Since the first description of the concept of natural orifice translumenal endoscopic surgery (NOTES), a substantial number of clinical NOTES reports have appeared in the literature. This editorial reviews the available human data addressing research questions originally proposed by the white paper, including determining the optimal method of access for NOTES, developing safe methods of lumenal closure, suturing and anastomotic devices,advanced multitasking platforms, addressing the risk of infection, managing complications, addressing challengeswith visualization, and training for NOTES procedures.An analysis of the literature reveals that so far transvaginal access and closure appear to be the most feasible techniques for NOTES, with a limited, but growing transgastric, transrectal, and transesophageal NOTES experience in humans. The theoretically increased risk of infection as a result of NOTES procedures has not been substantiated in transvaginal and transgastric procedures so far. Development of suturing and anastomotic devices and advanced platforms for NOTES has progressed slowly,with limited clinical data on their use so far. Data on the optimal management and incidence of intraoperative complications remain sparse, although possible factorscontributing to complications are discussed. Finally, this editorial discusses the likely direction of future NOTES development and its possible role in clinical practice.

Transluminal color-coded three-dimensional magnetic resonance angiography for visualization of signal Intensity distribution pattern within an unruptured cerebral aneurysm: preliminarily assessment with anterior communicating artery aneurysms

International Nuclear Information System (INIS)

Satoh, T.; Ekino, C.; Ohsako, C.

2004-01-01

The natural history of unruptured cerebral aneurysm is not known; also unknown is the potential growth and rupture in any individual aneurysm. The authors have developed transluminal color-coded three-dimensional magnetic resonance angiography (MRA) obtained by a time-of-flight sequence to investigate the interaction between the intra-aneurysmal signal intensity distribution patterns and configuration of unruptured cerebral aneurysms. Transluminal color-coded images were reconstructed from volume data of source magnetic resonance angiography by using a parallel volume-rendering algorithm with transluminal imaging technique. By selecting a numerical threshold range from a signal intensity opacity chart of the three-dimensional volume-rendering dataset several areas of signal intensity were depicted, assigned different colors, and visualized transparently through the walls of parent arteries and an aneurysm. Patterns of signal intensity distribution were analyzed with three operated cases of an unruptured anterior communicating artery aneurysm and compared with the actual configurations observed at microneurosurgery. A little difference in marginal features of an aneurysm was observed; however, transluminal color-coded images visualized the complex signal intensity distribution within an aneurysm in conjunction with aneurysmal geometry. Transluminal color-coded three-dimensional magnetic resonance angiography can thus provide numerical analysis of the interaction between spatial signal intensity distribution patterns and aneurysmal configurations and may offer an alternative and practical method to investigate the patient-specific natural history of individual unruptured cerebral aneurysms. (orig.)

Percutaneous transluminal angioplasty of infrarenal arteries in intermittent claudication

DEFF Research Database (Denmark)

Henriksen, L O; Jørgensen, B; Holstein, P E

1988-01-01

Percutaneous transluminal angioplasty was performed on 55 iliac and 31 femoropopliteal arteries in 71 patients with intermittent claudication (23 women, 48 men). The two-year patency rate was 80% after iliac and 41% after femoropopliteal angioplasty. In 17 femoropopliteal cases with lesions greater...... than or equal to 5 cm the 2-year patency rate was only 32%, but the corresponding figure for shorter lesions was 53%. Complicating haematoma appeared in 10% of the cases and the arterial state deteriorated in one patient. There was no distal embolization. Percutaneous transluminal angioplasty...

Motion of a single quantized vortex in an orifice

International Nuclear Information System (INIS)

Schwarz, K.W.

1993-01-01

Discrete phase-slip events are observed when superfluid 4 He moves through a microscopic orifice. In order to understand such behavior, one must know (a) how a quantized vortex is introduced into the orifice, and (b) how such a vortex evolves fluid dynamically so as to absorb energy from the applied flow field. To begin the study of the latter question, the authors present calculations done with an idealized orifice geometry. It is found that vortex loops larger than a critical size are carried out of the orifice and stretched by the diverging flow. As it stretches, such a vortex will cross the orifice, the energy required to stretch the vortex being absorbed from the flow field. Both a vortex loop introduced directly into the orifice and a remanent vortex extending to infinity will be discussed

Percutaneous transluminal biopsy using 7F forceps for diagnosing malignant biliary obstruction

Energy Technology Data Exchange (ETDEWEB)

Bahn, Young Eun; Kim, Young Hwan; An, Eun Jung; Kim, See Hyung [Keimyung Univ. College of Medicine, Daegu (Korea, Republic of)

2012-07-15

To evaluate the usefulness of the percutaneous transluminal biopsy using 7-F forceps for diagnosing malignant biliary obstruction. One hundred and seven consecutive patients with obstructive jaundice underwent transluminal forceps biopsy. The lesions involved the common bile duct (n = 33), common hepatic duct (n = 13), hilum (n = 17), right or left intrahepatic bile duct (n = 32), multiple sites (extra and intrahepatic ducts, n = 7), or anastomotic sites (n = 5). In each patient, an average of three specimens was taken with 7F biopsy forceps through a transhepatic biliary drainage tract. The final diagnosis was confirmed with pathologic findings, or a clinical and radiologic follow up. The final diagnoses showed malignancies in 75 patients and benign biliary obstructions in 32 patients. Pathologic classifications of malignancies established by forceps biopsy included 67 adenocarcinomas, 1 adenosquamous cell carcinoma, and 1 hepatocelluar carcinoma. There were 6 false-negative diagnoses. The diagnostic performance of transluminal forceps biopsy in malignant biliary obstruction had a sensitivity of 92%, specificity of 100%, positive predictive value of 100%, a negative predictive value of 84.2%, and an accuracy of 94.2%. Percutaneous transluminal forceps biopsy is a safe procedure that is easy to perform through a transhepatic biliary drainage tract. It is a highly accurate technique for diagnosing malignant biliary obstructions.

Experimental investigation of hydrodynamic cavitation through orifices of different geometries

Science.gov (United States)

Rudolf, Pavel; Kubina, Dávid; Hudec, Martin; Kozák, Jiří; Maršálek, Blahoslav; Maršálková, Eliška; Pochylý, František

Hydrodynamic cavitation in single and multihole orifices was experimentally investigated to assess their hydraulic characteristics: loss coefficients, inception cavitation number, cavitation number for transition to supercavitation. Significant difference for singlehole and multihole orifices was observed in terms of the measured loss coefficient. It is significantly more effective to use multihole orifices, where energy dissipation is much lower.It was found that using scaling factor given by ratio of orifice thickness suggests linear behaviour of both loss coefficient and inception cavitation number. Orifices seem to be convenient choice as flow constriction devices inducing cavitation due to their simplicity.

Experimental investigation of hydrodynamic cavitation through orifices of different geometries

Directory of Open Access Journals (Sweden)

Rudolf Pavel

2017-01-01

Full Text Available Hydrodynamic cavitation in single and multihole orifices was experimentally investigated to assess their hydraulic characteristics: loss coefficients, inception cavitation number, cavitation number for transition to supercavitation. Significant difference for singlehole and multihole orifices was observed in terms of the measured loss coefficient. It is significantly more effective to use multihole orifices, where energy dissipation is much lower.It was found that using scaling factor given by ratio of orifice thickness suggests linear behaviour of both loss coefficient and inception cavitation number. Orifices seem to be convenient choice as flow constriction devices inducing cavitation due to their simplicity.

Minimum wall pressure coefficient of orifice plate energy dissipater

Directory of Open Access Journals (Sweden)

Wan-zheng Ai

2015-01-01

Full Text Available Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics: the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter; the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter; and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.

Trabectome-Initiated Gonioscopy-Assisted Transluminal Trabeculotomy.

Science.gov (United States)

Smith, Brett L; Ellyson, Austin C; Kim, Won I

2018-03-01

To introduce a trabectome-initiated gonioscopy-assisted transluminal trabeculotomy (TIGATT) procedure and to report preliminary results. A preliminary case series of eight patients who have undergone the newly proposed TIGATT procedure is presented. TIGATT is a new concept that modifies established techniques by replacing the initial goniotomy incision of gonioscopy-assisted transluminal trabeculotomy (GATT) with an ab interno trabeculectomy ablation utilizing the trabectome. All surgeries were performed by a single surgeon (W.I.K.) between November 2014 and October 2015 in adults with primary open-angle glaucoma. Recorded outcome measures were intraocular pressure (IOP), number of medications, and complications. Eight patients with an age range of 63-93 yr underwent TIGATT with at least 3 mo of follow-up. Five of the eight initial patients had follow-up to 2 yr. The mean pre-operative IOP was 25 mmHg (standard deviation [SD] 7.0) on four medications (SD 1.1). The mean post-operative IOP at 3 mo was 14 mmHg (SD 1.8) on two medications (SD 1.3). The average decrease in IOP was 9.9 mmHg (SD 7.5) with an average decrease in medications of two (SD 1.4) at 3 mo. At 2 yr, the mean post-operative IOP was 14 mmHg (SD 3.2) on one medication (SD 1.1). The average decrease in IOP was 7.8 mmHg (SD 3.1) with an average decrease in medications of two (SD 1.8). There were two treatment failures that required further glaucoma surgery and one patient was lost to follow-up. The preliminary results and safety profile for TIGATT are promising and appear at least comparable with previously published results for both GATT and trabectome. Initiating the transluminal trabeculotomy with trabectome clearly exposes Schlemm's canal and facilitates threading the microcatheter into the canal. Additionally, if the 360-degree trabeculotomy cannot be completed because of an incompletely patent Schlemm's canal, the patient will at least have a trabectome ablation that can serve as their glaucoma

Calibration and use of filter test facility orifice plates

Science.gov (United States)

Fain, D. E.; Selby, T. W.

1984-07-01

There are three official DOE filter test facilities. These test facilities are used by the DOE, and others, to test nuclear grade HEPA filters to provide Quality Assurance that the filters meet the required specifications. The filters are tested for both filter efficiency and pressure drop. In the test equipment, standard orifice plates are used to set the specified flow rates for the tests. There has existed a need to calibrate the orifice plates from the three facilities with a common calibration source to assure that the facilities have comparable tests. A project has been undertaken to calibrate these orifice plates. In addition to reporting the results of the calibrations of the orifice plates, the means for using the calibration results will be discussed. A comparison of the orifice discharge coefficients for the orifice plates used at the seven facilities will be given. The pros and cons for the use of mass flow or volume flow rates for testing will be discussed. It is recommended that volume flow rates be used as a more practical and comparable means of testing filters. The rationale for this recommendation will be discussed.

Transluminal laser angioplasty

Science.gov (United States)

Otto, Wlodzimierz

1996-03-01

Twenty seven patients with femoral artery occlusion were treated by transluminal Nd:YAG laser angioplasty, in 16 patients the procedure was combined with intraarterial infusion of rTPA (actilyse-Boehringer Ing). In 5 out of 11 patients from the initial group recanalization was not successful. In 16 patients from the rTPA group satisfactory immediate results were achieved in all cases. In long time observations ranging from 9 to 24 months all patients remained free from symptoms, although in 4 of them angiography and Doppler ultrasound examination reveal no flow in the femoral artery. In the remaining 12 patients (75%), the previously occluded artery is patent. No complications of laser angioplasty nor intraarterial infusion of rTPA were noted in this series.

Fast-track video-assisted thoracoscopic surgery

DEFF Research Database (Denmark)

Holbek, Bo Laksafoss; Petersen, René Horsleben; Kehlet, Henrik

2016-01-01

Objectives To provide a short overview of fast-track video-assisted thoracoscopic surgery (VATS) and to identify areas requiring further research. Design A literature search was made using key words including: fast-track, enhanced recovery, video-assisted thoracoscopic surgery, robot......-assisted thoracoscopic surgery (RATS), robotic, thoracotomy, single-incision, uniportal, natural orifice transluminal endoscopic surgery (NOTES), chest tube, air-leak, digital drainage, pain management, analgesia, perioperative management, anaesthesia and non-intubated. References from articles were screened for further...

Investigation of wall mass transfer characteristics downstream of an orifice

International Nuclear Information System (INIS)

El-Gammal, M.; Ahmed, W.H.; Ching, C.Y.

2012-01-01

Highlights: ► Numerical simulations were performed for the mass transfer downstream of an orifice. ► The Low Reynolds Number K-ε turbulence model was used. ► The numerical results were in good agreement with existing experimental results. ► The maximum Sherwood number downstream of the orifice was significantly affected by the Reynolds number. ► The Sherwood number profile was well correlated with the turbulence kinetic energy profile close to the wall. - Abstract: Numerical simulations were performed to determine the effect of Reynolds number and orifice to pipe diameter ratio (d o /d) on the wall mass transfer rate downstream of an orifice. The simulations were performed for d o /d of 0.475 for Reynolds number up to 70,000. The effect of d o /d was determined by performing simulations at a Reynolds number of 70,000 for d o /d of 0.375, 0.475 and 0.575. The momentum and mass transport equations were solved using the Low Reynolds Number (LRN) K-ε turbulence model. The Sherwood number (Sh) profile downstream of the orifice was in relatively good agreement with existing experimental results. The Sh increases sharply downstream of the orifice, reaching a maximum within 1–2 diameters downstream of the orifice, before relaxing back to the fully developed pipe flow value. The Sh number well downstream of the orifice was in good agreement with results for fully developed pipe flow estimated from the correlation of . The peak Sh numbers from the simulations were higher than that predicted from and .

A Mandibular Second Premolar with Three Canals and Atypical Orifices

Directory of Open Access Journals (Sweden)

Neha Agarwal

2013-01-01

Full Text Available Background: Mandibular second premolars with three canals (Type V, Vertucci and separate foramina are very rare. The anatomy of the pulp chamber floor in these premolars usually reveals one lingual and two buccal orifices at the same level. This case report describes a second premolar with three canals and an unusual pulpal floor anatomy with one mesiobuccal and one distobuccal orifice at the same level and an orifice on the distolingual wall. Very careful examination of the pulpal space with an optical device and preoperative spiral computed tomography is recommended to locate any unusual orifices.

Killing rate of colony count by hydrodynamic cavitation due to square multi-orifice plates

Science.gov (United States)

Dong, Zhiyong; Zhao, Wenqian

2018-02-01

Currently,in water supply engineering, the conventional technique of disinfection by chlorination is employed to kill pathogenic microorganisms in raw water. However, chlorine reacts with organic compounds in water and generates disinfection byproducts (DBPs), such as trihalomethanes (THMs), haloacetic acids (HAAs) etc. These byproducts are of carcinogenic, teratogenic and mutagenic effects, which seriously threaten human health. Hydrodynamic cavitation is a novel technique of drinking water disinfection without DBPs. Effects of orifice size, orifice number and orifice layout of multi-orifice plate, cavitation number, cavitation time and orifice velocity on killing pathogenic microorganisms by cavitation were investigated experimentally in a self-developed square multi-orifice plate-type hydrodynamic cavitation device. The experimental results showed that cavitation effects increased with decrease in orifice size and increase in orifice number, cavitation time and orifice velocity. Along with lowering in cavitation number, there was an increase in Reynolds shear stress,thus enhancing the killing rate of pathogenic microorganism in raw water. In addition, the killing rate by staggered orifice layout was greater than that by checkerboard-type orifice layout.

Pressure atomizer having multiple orifices and turbulent generation feature

Science.gov (United States)

VanBrocklin, Paul G.; Geiger, Gail E.; Moran, Donald James; Fournier, Stephane

2002-01-01

A pressure atomizer includes a silicon plate having a top surface and a bottom surface. A portion of the top surface defines a turbulent chamber. The turbulent chamber is peripherally bounded by the top surface of the plate. The turbulent chamber is recessed a predetermined depth relative to the top surface. The silicon plate further defines at least one flow orifice. Each flow orifice extends from the bottom surface of the silicon plate to intersect with and open into the turbulent chamber. Each flow orifice is in fluid communication with the turbulent chamber.

Occurrence and prevention of enhanced oxide deposition in boiler flow control orifices

International Nuclear Information System (INIS)

Woolsey, I.S.; Thomas, D.M.; Garbett, K.; Bignold, G.J.

1989-10-01

Once-through boilers, such as those of the AGRs, incorporate flow control orifices at the boiler inlet to ensure a satisfactory flow distribution and stability in the parallel flow paths of the boiler. Deposition of corrosion products in the flow control orifice leads to changes in the orifice pressure loss characteristics, which could lead to problems of flow maldistribution within the boiler, and any adverse consequences resulting from this, such as tube overheating. To date, AGR boiler inlet orifices have not suffered significant fouling due to corrosion products in the boiler feedwater. However, oxide deposition in orifices has been observed in other plants, and in experimental loops operating under conditions very similar to those at inlet to AGR boilers. The lack of deposition in AGR flow control orifices is therefore somewhat surprising. This Report describes studies carried out to examine the factors controlling oxide deposition in flow control orifices, the intention of the work being to explain why deposition has not occurred in AGR boilers to date, and to provide means of preventing deposition in the future should this prove necessary. (author)

Numerical analysis for the flow field past a two-staged conical orifice

International Nuclear Information System (INIS)

Kim, Yeon Soo; Kim, You Gon

2001-01-01

The objective of the paper was to measure the pressure drop and to investigate the recirculation region of the conical orifices used in Kwang-yang Iron and Steel Company. The flow field with water used as a working fluid was the turbulent flow for Reynolds number of 2x10 4 . The effective parameters for the pressure drop and the recirculation region were the conical orifice's inclined angle (θ) against the wall, the interval(L) between orifices, the relative angle of rotation(α) of the orifices, the shape of the orifice's hole(circle, rectangle, triangle) having the same area. It was found that the shape of the orifice's hold affected the pressure drop and the flow field a lot. But the other parameters did not make much differences to the pressure drop. The PISO algorithm with FLUENT code was employed

Segmentally enclosed thrombolysis in percutaneous transluminal angioplasty for femoropopliteal occlusions

DEFF Research Database (Denmark)

Jørgensen, B; Tønnesen, K H; Nielsen, J D

1991-01-01

Segmentally enclosed thrombolysis (SET) was performed immediately following 34 percutaneous transluminal angioplasties (PTAs) for femoropopliteal occlusions. The dilated segment was sealed off with a double balloon catheter, and recombinant tissue plasminogen activator (rt-PA) 1 mg/ml and heparin...

Return to axi-symmetry for pipe flows generated after a fractal orifice

Energy Technology Data Exchange (ETDEWEB)

Nicolleau, F C G A, E-mail: F.Nicolleau@Sheffield.ac.uk [SFMG, Department of Mechanical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

2013-12-15

We present experimental results obtained from pipe flows generated by fractal shaped orifices or openings. We compare different fractal orifices and their efficiencies to re-generate axi-symmetric flows and to return to the standard flow generated by a perforated plate or a circular orifice plate. We consider two families of fractal openings: mono-orifice and complex orifice and emphasize the differences between the two fractal families. For the Reynolds number we used, we found that there is an optimum iteration for the fractal level above which no improvement for practical applications such as flowmetering is to be expected. The main parameters we propose for the characterization of the fractal orifice are the connexity parameter, the symmetry angle and the gap to the wall {delta}*{sub g}. The results presented here are among the first for flows forced through fractal openings and will serve as a reference for future studies and benchmarks for numerical applications. (paper)

Return to axi-symmetry for pipe flows generated after a fractal orifice

International Nuclear Information System (INIS)

Nicolleau, F C G A

2013-01-01

We present experimental results obtained from pipe flows generated by fractal shaped orifices or openings. We compare different fractal orifices and their efficiencies to re-generate axi-symmetric flows and to return to the standard flow generated by a perforated plate or a circular orifice plate. We consider two families of fractal openings: mono-orifice and complex orifice and emphasize the differences between the two fractal families. For the Reynolds number we used, we found that there is an optimum iteration for the fractal level above which no improvement for practical applications such as flowmetering is to be expected. The main parameters we propose for the characterization of the fractal orifice are the connexity parameter, the symmetry angle and the gap to the wall δ* g . The results presented here are among the first for flows forced through fractal openings and will serve as a reference for future studies and benchmarks for numerical applications. (paper)

EUS-guided biliary drainage by using a standardized approach for malignant biliary obstruction: rendezvous versus direct transluminal techniques (with videos).

Science.gov (United States)

Khashab, Mouen A; Valeshabad, Ali Kord; Modayil, Rani; Widmer, Jessica; Saxena, Payal; Idrees, Mehak; Iqbal, Shahzad; Kalloo, Anthony N; Stavropoulos, Stavros N

2013-11-01

EUS-guided biliary drainage (EGBD) can be performed via direct transluminal or rendezvous techniques. It is unknown how both techniques compare in terms of efficacy and adverse events. To describe outcomes of EGBD performed by using a standardized approach and compare outcomes of rendezvous and transluminal techniques. Retrospective analysis of prospectively collected data. Two tertiary-care centers. Consecutive jaundiced patients with distal malignant biliary obstruction who underwent EGBD after failed ERCP between July 2006 and December 2012 were included. EGBD by using a standardized algorithm. Technical success, clinical success, and adverse events. During the study period, 35 patients underwent EGBD (rendezvous n = 13, transluminal n = 20). Technical success was achieved in 33 patients (94%), and clinical success was attained in 32 of 33 patients (97.0%). The mean postprocedure bilirubin level was 1.38 mg/dL in the rendezvous group and 1.33 mg/dL in the transluminal group (P = .88). Similarly, length of hospital stay was not different between groups (P = .23). There was no significant difference in adverse event rate between rendezvous and transluminal groups (15.4% vs 10%; P = .64). Long-term outcomes were comparable between groups, with 1 stent migration in the rendezvous group at 62 days and 1 stent occlusion in the transluminal group at 42 days after EGBD. Retrospective analysis, small number of patients, and selection bias. EGBD is safe and effective when the described standardized approach is used. Stent occlusion is not common during long-term follow-up. Both rendezvous and direct transluminal techniques seem to be equally effective and safe. The latter approach is a reasonable alternative to rendezvous EGBD. Copyright © 2013. Published by Mosby, Inc.

Design and analysis of throttle orifice applying to small space with large pressure drop

International Nuclear Information System (INIS)

Li Yan; Lu Daogang; Zeng Xiaokang

2013-01-01

Throttle orifices are widely used in various pipe systems of nuclear power plants. Improper placement of orifices would aggravate the vibration of the pipe with strong noise, damaging the structure of the pipe and the completeness of the system. In this paper, effects of orifice diameter, thickness, eccentric distance and chamfering on the throttling are analyzed applying CFD software. Based on that, we propose the throttle orifices which apply to small space with large pressure drop are multiple eccentric orifices. The results show that the multiple eccentric orifices can effectively restrain the cavitation and flash distillation, while generating a large pressure drop. (authors)

Orifice design for the control of coupled region flow

International Nuclear Information System (INIS)

Atherton, R.; Spadaro, P.R.; Brummerhop, F.G.

1975-01-01

A fluid system arrangement for nuclear reactors is described comprising a triplate orifice apparatus which simultaneously controls core flow distribution, flow rate ratio between hydraulically coupled regions of the blanket and radial static pressure gradients entering and leaving the blanket fuel region. The design of the apparatus is based on the parameters of the diameter of the orifice holes, the friction factor, and expansion, contraction and turning pressure loss coefficients of the geometry of each orifice region. These above parameters are properly matched to provide the desired pressure drop, flow split and negligible cross flow at the interface of standard and power-flattened open lattice blanket regions. (U.S.)

Noise generated by cavitating single-hole and multi-hole orifices in a water pipe

NARCIS (Netherlands)

Testud, P.; Moussou, P.; Hirschberg, A.; Aurégan, Y.

2007-01-01

This paper presents an experimental study of the acoustical effects of cavitation caused by a water flow through an orifice. A circular-centered single-hole orifice and a multi-hole orifice are tested. Experiments are performed under industrial conditions: the pressure drop across the orifice varies

The influence of chamfering and corner radiusing on the discharge coefficient of rotating axial orifices

International Nuclear Information System (INIS)

Idris, A; Pullen, K

2013-01-01

The effects of chamfering and corner radiusing on the discharge coefficient of rotating axial orifices are presented in this paper. Both experimental and CFD results show that chamfering and corner radiusing improve the discharge coefficient of rotating orifices. For non-inclined rotating orifices, the discharge coefficient reduces with increasing speed, but chamfered and radiused orifices manage to have higher discharge coefficient (C d ) than the straight edge orifices. Comparing between chamfering and corner radiusing, the radiused corner orifice has the highest C d at every rotational speed. This is because the inlet radius helps guiding the flow into the orifice and avoiding flow separation at the inlet.

Energy dissipation characteristics of sharp-edged orifice plate

Directory of Open Access Journals (Sweden)

Ai Wanzheng

2015-08-01

Full Text Available The energy loss coefficient, relating directly to the energy dissipation ratio, is an important index of this energy dissipater. In this article, this coefficient and its affecting parameters were analyzed by theoretical considerations, and their relationships were obtained by numerical simulations. It could be concluded that the energy loss coefficient of sharp-edged orifice plate and its backflow region length were mainly dominated by the contraction ratio of the orifice plate. Sharp-edged orifice plate’s energy loss coefficient and its backflow region length all increase slightly with the increase in its thickness. When Reynolds number is in the range of 9.00×104–10.3×106, Reynolds number has little impacts on energy loss coefficient and backflow region length. Two empirical expressions, relating to backflow region length and energy loss coefficient, respectively, were presented.

A pulse-tube refrigerator using variable-resistance orifice

Science.gov (United States)

Huang, B. J.; Sun, B. W.

2003-01-01

In the present study, we propose a new design of orifice pulse-tube refrigerator (VROPT) using a variable-resistance valve to replace the conventional orifice. The variable-resistance orifice (VRO) is basically a high-speed solenoidal valve similar to the fuel jet device widely used in automobile engines. By changing the frequency and periods of ON and OFF of the valve through an electronic device, we can change the flow resistance of the VRO. This thus provides a possibility for an OPT to be controlled on-line during operation. From the results obtained in the present study, we have shown that VROPT is able to achieve on-line control by regulating the duty cycle d or frequency fv of the VRO. We also show that VROPT will not loss its thermal performance as compared to conventional OPT.

The Impact of Manifold-to-Orifice Turning Angle on Sharp-Edge Orifice Flow Characteristics in both Cavitation and Non-Cavitation Turbulent Flow Regimes (Preprint)

Science.gov (United States)

2007-06-01

varies as the cavitation number is lowered. The third is supercavitation where the vapor pocket attachment has moved to the orifice exit and beyond but...the flow still acts as attached. For this study only the 90 degree orifice angle configuration experienced supercavitation . For all other angles

Evaluation of RF properties by orifice design for IFMIF RFQ

International Nuclear Information System (INIS)

Maebara, Sunao; Sugimoto, Masayoshi

2005-03-01

Orifices for the IFMIF RFQ have been designed and fabricated, and RF properties have been evaluated by a network analyzer. The designed orifices were installed into a vacuum port of the 1.1m-long RFQ mock-up module, and the resonant frequency and the phase difference between cavities were measured for a quadrupole operation mode of TE 210 . It was found that the RF properties are not affected on condition that slit direction with the same direction of current flow at the RFQ wall. Orifice conductance from 0.22 to 0.25 m 3 /sec by nitrogen conversion at room temperature was designed, and an ultimate pressure level of 5x10 -7 [Pa] was evaluated for the 4.1m-long central module for the IFMIF RFQ. It was concluded that the designed orifices are effective for RF properties and vacuum conductance in the IFMIF RFQ. (author)

Energy Efficiency for Biodiesel Production by Combining Two Orifices in Hydrodynamic Cavitation Reactor

OpenAIRE

Mahlinda, Mahlinda; Djafar, Fitriana

2014-01-01

Research of energy efficiency for biodiesel production process by combining two orifices on  hydrodynamic cavitation reactor had been carried out. The aim of this reseach was to studied effect of the number of orifices toward increasing temperature without using external energy source to produce biodiesel that generated by cavitation effects on orifices. The results of preliminary research showed by combining two orifices arranged in series can produce the highest thermal energy reached 48oC....

Fabrication of small-orifice fuel injectors for diesel engines.

Energy Technology Data Exchange (ETDEWEB)

Woodford, J. B.; Fenske, G. R.

2005-04-08

Diesel fuel injector nozzles with spray hole diameters of 50-75 {micro}m have been fabricated via electroless nickel plating of conventionally made nozzles. Thick layers of nickel are deposited onto the orifice interior surfaces, reducing the diameter from {approx}200 {micro}m to the target diameter. The nickel plate is hard, smooth, and adherent, and covers the orifice interior surfaces uniformly.

Choked flow mechanism of HFC-134a flowing through short-tube orifices

Energy Technology Data Exchange (ETDEWEB)

Nilpueng, Kitti; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok (Thailand)

2011-02-15

This paper is a continuation of the author's previous work. New experimental data on the occurrence of choked flow phenomenon and mass flow rate of HFC-134a inside short-tube orifices under choked flow condition are presented. Short-tube orifices diameters ranging from 0.406 mm to 0.686 mm with lengths ranging from 1 mm to 3 mm which can be applied to a miniature vapour-compression refrigeration system are examined. The experimental results indicated that the occurrence of choked flow phenomena inside short-tube orifices is different from that obtained from short-tube orifice diameters of greater than 1 mm, which are typically used in air-conditioner. The beginning of choked flow is dependent on the downstream pressure, degree of subcooling, and length-to-diameter ratio. Under choked flow condition, the mass flow rate is greatly varied with the short-tube orifice dimension, but it is slightly affected by the operating conditions. A correlation of mass flow rate through short-tube orifices is proposed in terms of the dimensionless parameters. The predicted results show good agreement with experimental data with a mean deviation of 4.69%. (author) transfer coefficient was also proposed. (author)

Minimally invasive approaches for gastric cancer-Korean experience.

Science.gov (United States)

Yang, Han-Kwang; Suh, Yun-Suhk; Lee, Hyuk-Joon

2013-03-01

Laparoscopic surgery in Korea increased rapidly because of the early detection of gastric cancer by the development of diagnostic tools and nationwide screening. The Korean Laparoscopic Gastrointestinal Surgery Study Group (KLASS group) played a leading role in various projects related with minimally invasive surgery. The justification of minimally invasive procedures including robotic surgery, sentinel-node biopsy, or single-port surgery/Natural Orifice Transluminal Endoscopic Surgery (NOTES) must be predetermined by the clinical trial before a wide application, and the medical industry as well as surgeons should have great responsibility. Copyright © 2012 Wiley Periodicals, Inc.

The Double-Orifice Valve Technique to Treat Tricuspid Valve Incompetence.

Science.gov (United States)

Hetzer, Roland; Javier, Mariano; Delmo Walter, Eva Maria

2016-01-01

A straightforward tricuspid valve (TV) repair technique was used to treat either moderate or severe functional (normal valve with dilated annulus) or for primary/organic (Ebstein's anomaly, leaflet retraction/tethering and chordal malposition/tethering, with annular dilatation) TV incompetence, and its long-term outcome assessed. A double-orifice valve technique was employed in 91 patients (mean age 52.6 ± 23.2 years; median age 56 years; range: 0.6-82 years) with severe tricuspid regurgitation. Among the patients, three had post-transplant iatrogenic chordal rupture, five had infective endocarditis, 11 had mitral valve insufficiency, 23 had Ebstein's anomaly, and 47 had isolated severe TV incompetence. The basic principle was to reduce the distance between the coapting leaflets, wherein the most mobile leaflet could coapt to the opposite leaflet, by creating two orifices, ensuring valve competence. The TV repair was performed through a median sternotomy or right anterior thoracotomy in the fifth intercostal space under cardiopulmonary bypass. The degree and extent of creating a double-valve orifice was determined by considering the minimal body surface area (BSA)-related acceptable TV diameter. Repair was accomplished by passing pledgeted mattress sutures from the middle of the true anterior annulus to a spot on the opposite septal annulus, located approximately two-thirds of the length of the septal annulus to avoid injury to the bundle of His. The annular apposition divides the TV into a larger anterior and a smaller posterior orifices, enabling valve closure, on both sides. In adults, the diameter of the anterior valve orifice should be 23-25 mm, and the posterior orifice 15-18 mm; thus, the total valve orifice area is 5-6 cm2. In children, the total valve orifice should be a standard deviation of 1.7 mm for a BSA of 1.0m2. During a mean follow up of 8.7 ± 1.34 years (median 10 years; range: 1.5-25.9 years) there have been no reoperations for TV insufficiency

Sizing of high-pressure restriction orifices

International Nuclear Information System (INIS)

Casado Flores, E.

1995-01-01

Constant up-grading of power plants sometimes requires the modification of components which form part of suppliers' packages. In order to protect technology they have developed, however, the suppliers do not supply their calculation criteria. In order to reduce the costs of such improvements, and so as to be able to undertake the modification without having to rely on the original supplier, this paper describes the basic criteria applicable to the study of high-pressure restriction orifices, which can be considered to be representative of the components in question. The restriction orifices discussed are: - Insert - Multiplates in series with one perforation in each plate - Multiplates in series with several perforations in each plate For each type, an explanation of their sizing is given, together with the equations relating the corresponding flow and pressure drop. (Author)

Optimization of Orifice Geometry for Cross-Flow Mixing in a Cylindrical Duct

Science.gov (United States)

Kroll, J. T.; Sowa, W. A.; Samuelsen, G. S.

1996-01-01

Mixing of gaseous jets in a cross-flow has significant applications in engineering, one example of which is the dilution zone of a gas turbine combustor. Despite years of study, the design of the jet injection in combustors is largely based on practical experience. The emergence of NO(x) regulations for stationary gas turbines and the anticipation of aero-engine regulations requires an improved understanding of jet mixing as new combustor concepts are introduced. For example, the success of the staged combustor to reduce the emission of NO(x) is almost entirely dependent upon the rapid and complete dilution of the rich zone products within the mixing section. It is these mixing challenges to which the present study is directed. A series of experiments was undertaken to delineate the optimal mixer orifice geometry. A cross-flow to core-flow momentum-flux ratio of 40 and a mass flow ratio of 2.5 were selected as representative of a conventional design. An experimental test matrix was designed around three variables: the number of orifices, the orifice length-to- width ratio, and the orifice angle. A regression analysis was performed on the data to arrive at an interpolating equation that predicted the mixing performance of orifice geometry combinations within the range of the test matrix parameters. Results indicate that the best mixing orifice geometry tested involves eight orifices with a long-to-short side aspect ratio of 3.5 at a twenty-three degree inclination from the center-line of the mixing section.

Comparison of turbulent flow through hexagram and hexagon orifices in circular pipes using large-eddy simulation

Energy Technology Data Exchange (ETDEWEB)

Wang, Wei; Nicolleau, Franck C G A; Qin, Ning, E-mail: n.qin@sheffield.ac.uk [Department of Mechanical Engineering, The University of Sheffield, Sheffield, S1 3JD (United Kingdom)

2016-04-15

Characteristics of turbulent flow through a circular, a hexagon and a hexagram orifice with the same flow area in circular pipes are investigated using wall-modelled large-eddy simulation. Good agreements to available experimental data were obtained in both the mean velocity and turbulent kinetic energy. The hexagram orifice with alternating convex and concave corners introduces outwards radial velocity around the concave corners downstream of the orifice plate stronger than the hexagon orifice. The stronger outwards radial velocity transfers high momentum from the pipe centre towards the pipe wall to energize the orifice-forced vortex sheet rolling-up and leads to a delayed vortex break-down. Correspondingly, the hexagram has a more gradual flow recovery to a pipe flow and a reduced pressure drop than the hexagon orifice. Both the hexagon and hexagram orifices show an axis-switching phenomenon, which is observed from both the streamwise velocity and turbulent kinetic energy contours. To the best knowledge of the authors, this is the first comparison of orifice-forced turbulence development, mixing and flow dynamics between a regular and a fractal-based polygonal orifice. (paper)

Treatment of renovascular hypertension by transluminal angioplasty

DEFF Research Database (Denmark)

Øvrehus, Kristian A; Andersen, Poul E; Jacobsen, Ib A

2007-01-01

: with improved control of blood pressure; group III: unchanged blood pressure control. Grouping was performed immediately after treatment, at 1 month, 6 months and at the latest follow-up. One hundred-and-twenty-two patients (124 atherosclerotic and 12 fibromuscular lesions) were treated during 13 years......OBJECTIVE: The study is a follow-up on treatment of renovascular hypertension (RVH) with percutaneous transluminal renal angioplasty (PTRA). METHODS: Patients were screened on the basis of clinical criteria of increased probability of RVH with renography and in selected cases with renal vein renin...

Amputation-Free Survival after Crural Percutaneous Transluminal Angioplasty for Critical Limb Ischemia

DEFF Research Database (Denmark)

Strøm, M; Konge, L; Lönn, L

2016-01-01

BACKGROUND AND AIM: To evaluate the amputation-free survival after below the knee percutaneous transluminal angioplasty in a consecutive group of patients with critical ischemia of the lower extremity. MATERIALS AND METHODS: A total of 70 consecutive patients with critical ischemia were treated......-up clinical examinations were performed within 6 weeks and after 1 year. All medical records were crosschecked with the national vascular registry ensuring a valid 1-year status in 97% of the patients. RESULTS: A total of 15 major amputations were performed during follow-up, with 11 amputations performed...... within the first year. Complications after percutaneous transluminal angioplasty were rare. Cumulative mortality after 1 and 2 years was 22% and 34%, respectively. Amputation-free survival at 1 and 2 years of follow-up was 68% and 58%, respectively. There were no association between known risk factors...

Orifice Mass Flow Calculation in NASA's W-8 Single Stage Axial Compressor Facility

Science.gov (United States)

Bozak, Richard F.

2018-01-01

Updates to the orifice mass flow calculation for the W-8 Single Stage Axial Compressor Facility at NASA Glenn Research Center are provided to include the effect of humidity and incorporate ISO 5167. A methodology for including the effect of humidity into the inlet orifice mass flow calculation is provided. Orifice mass flow calculations provided by ASME PTC-19.5-2004, ASME MFC-3M-2004, ASME Fluid Meters, and ISO 5167 are compared for W-8's atmospheric inlet orifice plate. Differences in expansion factor and discharge coefficient given by these standards give a variation of about +/- 75% mass flow except for a few cases. A comparison of the calculations with an inlet static pressure mass flow correlation and a fan exit mass flow integration using test data from a 2017 turbofan rotor test in W-8 show good agreement between the inlet static pressure mass flow correlation, ISO 5167, and ASME Fluid Meters. While W-8's atmospheric inlet orifice plate violates the pipe diameter limit defined by each of the standards, the ISO 5167 is chosen to be the primary orifice mass flow calculation to use in the W-8 facility.

Preparation of spherical particles by vibrating orifice technique

Science.gov (United States)

Shibata, Shuichi; Tomizawa, Atsushi; Yoshikawa, Hidemi; Yano, Tetsuji; Yamane, Masayuki

2000-05-01

Preparation of micrometer-sized spherical particles containing Rhodamine 6G (R6G) has been investigated for the spherical cavity micro-laser. Using phenyl triethoxy silane (PTES) as a starting material, R6G-doped monodisperse spherical particles were prepared by the vibrating orifice technique. Processing consists of two major processes: (1) Hydrolysis and polymerization of PTES and (2) Droplet formation from PTES oligomers by vibrating orifice technique. A cylindrical liquid jet passing through the orifice of 10 and 20 micrometers in diameter breaks up into equal- sized droplets by mechanical vibration. Alcohol solvent of these droplets was evaporated during flying with carrier gas and subsequently solidified in ammonium water trap. For making smooth surface and god shaped particles, control of molecular weight of PTES oligomer was essential. R6G-doped hybrid spherical particles of 4 to 10 micrometers size of cavity structure were successfully obtained. The spherical particles were pumped by a second harmonic pulse of Q- switched Nd:YAG laser and laser emission peaks were observed at wavelengths which correspond to the resonance modes.

Transport phenomena of macro and micro flows behind orifice and flow accelerated corrosion

International Nuclear Information System (INIS)

Fujisawa, Nobuyuki; Hayase, Toshiyuki; Ohara, Taku; Ikohagi, Toshiaki

2008-01-01

This paper describes experiment and numerical simulations for macro and micro flows behind an orifice model in a square pipe, which are carried from the viewpoint of flow accelerated corrosion (FAC). The measurements of velocity field behind the orifice model were carried out using particle image velocimetry, and the variations of velocity field with respect to the accuracy of the orifice position were studied. It is found that the reattachment behavior of the flow is highly influenced by the orifice position, which is a critical problem for predicting the pipe thinning phenomena by FAC. The DNS simulation was also conducted for calculating the macro flow behind the orifice. The result suggests that the DNS simulation is applicable to the prediction of pipe thinning macro flow for highly aged nuclear plant. The micro flow simulation can predict the pipe thinning phenomena near the wall. (author)

[Fourth branchial cleft deformity with skin orifice: a series of 10 cases].

Science.gov (United States)

Huang, S L; Zhang, B; Chen, L S; Liang, L; Luo, X N; Lu, Z M; Zhang, S Y

2016-10-07

Objective: To report rare cases of congenital neck cutaneous sinus with an orifice near the sternoclavicular joint and to investigate their origins and managements. Methods: A total of ten patients with congenital neck cutaneous sinus having an orifice near the sternoclavicular joint treated in the Guangdong General Hospital from January 2010 to June 2015 were retrospectively analyzed. Results: There four boys and six girls, aging from 11 months to 96 months with an average of 33.4 months, and they had a common feature showing a congenital cutaneous sinus with an orifice near sternoclavicular joint. Discharge of pus from the orifice or abscess formation was commonly seen soon after infection. With bacteriological study, staphylococcus aureus was positive in five cases and klebsiella pneumonia in a case. Another orifice of fistula/sinus was not depicted in pyriform with barium swallow X-ray in five cases Ultrasound studies of three cases demonstrated anechoic (i.e., nearly black) and solid-cystic lesion near sternoclavicular joint with posterior acoustic enhancement. Magnetic resonance imaging (MRI) showed isointensity of the lesion on T1 and T2 weighted images with heterogeneous enhancement and a close relationship with sternoclavicular joint. All patients underwent laryngoscopic examination, which showed no orifice of sinus in pyriform at same side. Surgical resection of fistula/sinus was performed in all cases. The lengths of the fistula varied from 5 mm to 22 mm with an average of 11 mm. Postoperative pathological examination showed all specimens were accordance with fistula. No complications were noticed. Recurrence was not observed in the cases by following-up of 6 months to 70 months (median: 33 months). Conclusion: Congenital neck cutaneous sinus with orifice near the sternoclavicular joint maybe a special clinical phenotype of the fourth branchial cleft sinus with skin orifice in cervicothoracic junction. Differential diagnoses between low cervical diseases

Percutaneous transluminal angioplasty in arteriosclerosis

International Nuclear Information System (INIS)

Chung, Soo Young; Cha, In Ho

1984-01-01

Percutaneous transluminal angioplasty (PTA) is a non-operative therapeutic procedure to the dilation of stenosis or to the recanalization of occlusion in atherosclerotic arteries using of dilatation catheters. PTA was performed 37 times in 34 patients with arteriosclerotic for 1 year and 4 months from March, 1982 to June, 1983 at department of radiology, Klinikum Barmen/west Germany. The results were as follows; 1. The male to female ratio was 2 : 1 and peak age range was from 61 to 70. 2. The most common indication was clinical stage II b with 19 cases (51.3%). 3. PTA was performed most commonly in superficial femora artery in 25 cases (67.5%). 4. Acute major complication occurred in 2 cases (5.4%). PTA is a alternative or complementary therapeutic procedure to vascular surgery.

The Timing and Frequency of Complications After Peripheral Percutaneous Transluminal Angioplasty and Iliac Stenting: Is a Change from Inpatient to Outpatient Therapy Feasible?

International Nuclear Information System (INIS)

Burns, Briony J.; Phillips, Andrea J.; Fox, Anthony; Boardman, Phillip; Phillips-Hughes, Jane

2000-01-01

Purpose: A prospective study was performed to assess the frequency and timing of complications after transluminal angioplasty and stent placement with a view to changing our practice and performing these procedures on an outpatient basis.Method: A total of 266 angioplasties and 51 stent deployments were attempted on 240 consecutive patients. Immediate complications were documented by the radiologists. The timing and nature of any complications during and beyond the first 24 hr were reported by the vascular surgeons.Results: There were 14 complications in 240 patients, giving a complication rate of 4.8% per vessel segment dilated. There were five major and nine minor complications. Eighty-six percent of complications were evident before the patient had left the angiography suite. All complications were evident within 4.5 hr of the procedure.Conclusion: The timing of complications suggests it would be reasonable to perform percutaneous transluminal angioplasties and iliac stenting on an outpatient basis in suitable patients

Percutaneous transluminal angioplasty (PTA) after kidney transplantation

International Nuclear Information System (INIS)

Fava, C.; Grosso, M.; Sandrone, M.; Malfi, B.; Segoloni, G.P.; Colla, L.

1988-01-01

Renal artery stenosis is a frequent complication of kidney transplantation (10%). Percutaneous transluminal angioplasty (PTA) has recently been proposed as a potential therapeutic procedure. Twelve transplant patients with arterial stenosis underwent PTA. The procedure was successful in 10 cases (83.3%). Restenosis occurred in 2 patients (16.7%); both of them underwent PTA successfully. No complications occurred. A considerable improvement in glomerular filtration rate and a reduction in high blood pressure were observed in all patients after successful PTA. The authors belive PTA to be the therapy of choice in the treatment of arterial stenoses in kidney transplant patients

The effect of orifice plate insertion on low NOx radial swirl burner performances (simulated variable area burner)

International Nuclear Information System (INIS)

Mohammad Nazri Mohd Jaafar

2000-01-01

The effect of inserting an outlet orifice plate of different sizes at the exit plane of the swirler outlet were studied for small radial swirler with fixed curves vanes. Tests were carried out using two different sizes flame tubes of 76 mm and 140 mm inside diameter, respectively and 330 mm in length. The system was fuelled via eight vane passage fuel nozzles of 3.5 mm diameter hole. This type of fuel injection helps in mixing the fuel and air better prior to ignition. Tests were carried out at 20 mm W.G. pressure loss which is representative of gas burners for domestic central heating system operating conditions. Tests were also carried out at 400 K preheated inlet air temperature and using only natural gas as fuel. The aim of the insertion of orifice plate was to create the swirler pressure loss at the swirler outlet phase so that the swirler outlet shear layer turbulence was maximize to assist with fuel/air mixing. For the present work, the smallest orifice plate exhibited a very low NO x emissions even at 0.7 equivalence ratio were NO x is well below 10 ppm corrected at 0% oxygen at dry basis. Other emissions such as carbon monoxide and unburned hydrocarbon were below 10 ppm and 100 ppm, respectively, over a wide range of operating equivalence ratios. The implies that good combustion was achieved using the smallest orifice plate. (Author)

Minimally invasive splenectomy: an update and review

Science.gov (United States)

Gamme, Gary; Birch, Daniel W.; Karmali, Shahzeer

2013-01-01

Laparoscopic splenectomy (LS) has become an established standard of care in the management of surgical diseases of the spleen. The present article is an update and review of current procedures and controversies regarding minimally invasive splenectomy. We review the indications and contraindications for LS as well as preoperative considerations. An individual assessment of the procedures and outcomes of multiport laparoscopic splenectomy, hand-assisted laparoscopic splenectomy, robotic splenectomy, natural orifice transluminal endoscopic splenectomy and single-port splenectomy is included. Furthermore, this review examines postoperative considerations after LS, including the postoperative course of uncomplicated patients, postoperative portal vein thrombosis, infections and malignancy. PMID:23883500

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.

Neutron Imaging study of bubble behaviors in Nanofluid Through Engineered Orifices

International Nuclear Information System (INIS)

Seo, Seok Bin; Bang, In Cheol; Kim, Tae Joo

2014-01-01

Most studies focused on the change of surface parameters through deposited nanoparticles, while Vafaei and Wen firstly discussed modification of bubble dynamics by dispersed nanoparticles in fluid as well as deposited ones. The boiling mechanism, as an effective heat transfer mode, includes bubble generation, growth, departure, and coalescence. Therefore the change of bubble dynamics can lead to the change of boiling heat transfer condition. That is, not only surface characteristics but the dispersed nanoparticles would be the essential parameters of boiling mechanism in terms of bubble dynamics. For advanced visualization of opaque fluids, the neutron imaging technique is introduced. In the present study, the bubble dynamics in nanofluid through engineered orifices was studied. The main parameters of engineered orifices are size and geometry. Photographic analysis of bubble departure frequency and averaged bubble departure volume provides as follows: With increasing orifice diameter, averaged bubble departure volume increases, while bubble departure frequency decreases. The results are attributed to enhanced capillary force by increasing contact perimeter. Averaged bubble departure volume and bubble departure frequency remain similar for three different types of orifices. But edges of the triangle and square orifice produce small bubbles which interrupts bubble generation. The converged triple contact line due to the edge may be a reason for the emerged baby bubbles. Nanofluid shows less averaged bubble departure volume and higher bubble departure frequency. Considering little change in physical properties of the fluid, interaction between bubble interface and nanoparticles may be in charge of the results

Nuclear Techniques for Coronary Heart Disease Therapy after Percutaneous Transluminal Coronary Angioplasty

International Nuclear Information System (INIS)

Nurlaila-Z

2005-01-01

Nuclear techniques studies of the heart represent one of the fastest growing areas of research. Several years ago, nuclear medicine cardiac studies were limited for the evaluation and diagnosis of myocardial infarction. Development in radiopharmaceutical-chemistry and instrumentation have made possible advances in nuclear medicine for restenosis cardiovascular therapy after percutaneous transluminal coronary angioplasty.The radionuclide as radiation source can be delivered to the target basically by two techniques, those are catheter-based systems and radioactive stents. For this purpose,it can be use the γ and β emitter radionuclides, in which the β emitter radionuclides is an ideal radionuclide for endovascular therapy. Restenosis after percutaneous transluminal coronary angioplasty can be prevented by using the radioactive stent. This review discusses several techniques which could be used for restenosis cardiovascular therapy. Furthermore, several types of radiopharmaceutical and kinds of radionuclides as well as doses of the compounds for this purpose are also reviewed. (author)

Value of Duplex scanning in the selection of patients for percutaneous transluminal angioplasty

NARCIS (Netherlands)

van der Heijden, F. H.; Legemate, D. A.; van Leeuwen, M. S.; Mali, W. P.; Eikelboom, B. C.

1993-01-01

Duplex scanning is becoming increasingly important in the diagnosis and follow-up of arterial lesions, though most surgeons and radiologists currently still prefer diagnostic angiography prior to percutaneous transluminal angioplasty (PTA). We performed PTA based on Duplex scanning alone in 31

Variable orifice using an iris shutter

International Nuclear Information System (INIS)

Beeman, R.; Brajkovich, S.J.

1978-01-01

A variable orifice forming mechanism is described that utilizes shutter arrangement adapted to control gas flow, conductance in vacuum systems, as a heat shield for furnace windows, as a beam shutter in sputtering operations, and in any other application requiring periodic or continuously-variable control of material, gas, or fluid flow

Localization of root canal orifices in mandibular second molars in relation to occlusal dimension.

Science.gov (United States)

Gorduysus, O; Nagas, E; Cehreli, Z C; Gorduysus, M; Yilmaz, Z

2009-11-01

To evaluate the localization and distribution of canal orifices of mandibular second molar teeth in relation to the mesio-distal and bucco-lingual dimensions of coronal tissue. Fifty extracted mandibular second molar teeth were embedded into plaster blocks with their vertical axes aligned perpendicular to the horizontal plane. The teeth were photographed digitally from the occlusal aspect under 12 x magnification. Thereafter, the occlusal halves of crowns were sectioned off to expose the root canal orifices. The teeth were than photographed under the same magnification, after which the pre- and post-sectioning images of each specimen were stacked into a single file. To plot the coordinate of each canal orifice, a 0.5-mm grid analytical plane was mounted digitally on the stack so that the x- and y-axes of the plane were superimposed on the mesiodistal and buccolingual axes (bisectors) of the tooth crowns. Localization and distribution of the coordinates of the canal orifices were evaluated using the chi-square test (P = 0.05). Only one tooth displayed a single root canal orifice, located in the mesiobuccal-distolingual 'centre' of the occlusal surface. The majority of mandibular second molars had three orifices (72%), followed by those with two (16%) and four (10%). The distal canal was located lingual to the centre of the occlusal plane. The distal canal was located lingual to the centre of the occlusal plane of mandibular second molars. The possibility of observing more divergent localizations and orifice numbers should not be overlooked in clinical practice.

Fabrication and Characterization of Device Pressure Regulation System Orifice of Manufacturing Process Gel Uranium Column Gelation External

International Nuclear Information System (INIS)

Triyono; Sutarni; Indra Suryawan

2009-01-01

The device pressure regulation orifice system of manufacturing process gel uranium on external column gelation has been made and characterized. The device consists : compressor 5.75-6.75 kg / cm 2 , air container tank, power supply 24 volts dc, solenoid valve 24 volts dc, pressure indicator 0-100 mbar, pressure indicator 0-250 mbar, mechanical valve and power electric 380 volts 50 Hz. The activity includes: installation device system and characterization with pressure variation orifice 5-75 mbar on the compressor 5.75-6.5 kg/cm 2 continuously for 1 minute. The method of installation i.e: wiring and piping to first component and support component (compressor and pressure air indicator, air container tank and pressure air indicator, solenoid valve, power supply 220 volts / 24 volts dc and orifice). After apparatus installed has been tested by the characterization without feed under air pressure varied to orifice of 5-75 mbar and device characterization with variation diameter orifice of 0.5-1 mm and orifice pressure of 5-75 mbar. The result in the characterization an every component good function, can be operation by input pressure range of 15-185 mbar orifice pressure range of 5-75 mbar. The characterization result device pressure regulation orifice system showed that: the system can be good operation of air pressure regulation orifice between 5-75 mbar with diameter orifice 0.5 mm to result gelation range of 10-25 piece / minute with variation air pressure input between 15-185 mbar of air pressure compressor 5.75-6.5 kg cm 2 . (author)

Effect of plate shapes in orifice plate type flowmeters

International Nuclear Information System (INIS)

Moeller, S.V.

1984-01-01

The study of unusual plate shapes in orifice plate type flowmeters is presented, with a view to providing data for the substitution of the plate with one centered circular orifice in those applications where its use is not possible. For this purpose, six pairs of plates with different forms, with and without chamfered edges, were made and tested in a closed water loop. Results show that, generally, the use of chamfers improves the results and, in the case of perforated and slotlike orificed plates, the narrow-ness of the fluid passage tends to make unnecessary its use. (Author) [pt

Flow-throttling orifice nozzle

International Nuclear Information System (INIS)

Sletten, H.L.

1975-01-01

A series-parallel-flow type throttling apparatus to restrict coolant flow to certain fuel assemblies of a nuclear reactor is comprised of an axial extension nozzle of the fuel assembly. The nozzle has a series of concentric tubes with parallel-flow orifice holes in each tube. Flow passes from a high pressure plenum chamber outside the nozzle through the holes in each tube in series to the inside of the innermost tube where the coolant, having dissipated most of its pressure, flows axially to the fuel element. (U.S.)

Gaseous Nitrogen Orifice Mass Flow Calculator

Science.gov (United States)

Ritrivi, Charles

2013-01-01

The Gaseous Nitrogen (GN2) Orifice Mass Flow Calculator was used to determine Space Shuttle Orbiter Water Spray Boiler (WSB) GN2 high-pressure tank source depletion rates for various leak scenarios, and the ability of the GN2 consumables to support cooling of Auxiliary Power Unit (APU) lubrication during entry. The data was used to support flight rationale concerning loss of an orbiter APU/hydraulic system and mission work-arounds. The GN2 mass flow-rate calculator standardizes a method for rapid assessment of GN2 mass flow through various orifice sizes for various discharge coefficients, delta pressures, and temperatures. The calculator utilizes a 0.9-lb (0.4 kg) GN2 source regulated to 40 psia (.276 kPa). These parameters correspond to the Space Shuttle WSB GN2 Source and Water Tank Bellows, but can be changed in the spreadsheet to accommodate any system parameters. The calculator can be used to analyze a leak source, leak rate, gas consumables depletion time, and puncture diameter that simulates the measured GN2 system pressure drop.

A Study of System Pressure Transients Generated by Isolation Valve Open/Closure in Orifice Manifold

Energy Technology Data Exchange (ETDEWEB)

Kim, M. [KEPCO, Daejeon (Korea, Republic of); Bae, S. W.; Kim, J. I.; Park, S. J. [KHNP, Abu Dhabi (United Arab Emirates)

2016-05-15

In this study, we explore the effects of pressure transients on peak and minimal pressures caused by the actuation of isolation valve and control valve reacting to the combined orifice operation of orifice manifold with motor-operated valve installed in the rear of the orifice. We then use the collected data to direct our effort towards cause analysis and propose improvements to efficiency and safety of operation. This formation is used to by domestic and foreign nuclear power plants as a mean to control flow rate, producing required flow rate jointly together by combination of the orifices. No significant impacts on the internals of manifold orifice due to peak pressure has been observed, although chance of cavitation at the outlet of control valve is significant. Considering the peak pressure, as well as minimum pressure occurs in low flow rate conditions, the pressure transient is more so affected by the characteristics (modified equal percentage) of control valve. Isolation valve of the orifice and control valve operate organically, therefore stroke time for valves need to be applied in order for both valves to cooperatively formulate an optimized operation.

Short- and long-term functional effects of percutaneous transluminal angioplasty in hemodialysis vascular access

NARCIS (Netherlands)

J. van der Linden (Joke); J.H. Smits (Johannes); J.H. Assink (Jan Hendrik); D.W. Wolterbeek (Derk); J.J. Zijlstra (Jan); G.H.T. de Jong (Gijs); M.A. van den Dorpel (Marinus); P.J. Blankestijn (Peter)

2002-01-01

textabstractThe efficacy of percutaneous transluminal angioplasty (PTA) is usually expressed as the angiographic result. Access flow (Qa) measurements offer a means to quantify the functional effects. This study was performed to evaluate the short-term functional and

Endoscopic treatment of multilocular walled-off pancreatic necrosis with the multiple transluminal gateway technique.

Science.gov (United States)

Jagielski, Mateusz; Smoczyński, Marian; Adrych, Krystian

2017-06-01

The development of minimally invasive techniques allowed access to the necrotic cavity through transperitoneal, retroperitoneal, transmural and transpapillary routes. The choice of access to walled-off pancreatic necrosis (WOPN) should depend not only on the spread of necrosis, but also on the experience of the clinical center. Herein we describe treatment of a patient with multilocular symptomatic walled-off pancreatic necrosis using minimally invasive techniques. The single transmural access (single transluminal gateway technique - SGT) to the necrotic collection of the patient was ineffective. The second gastrocystostomy was performed using the same minimally invasive technique as an extra way of access to the necrosis (multiple transluminal gateway technique - MTGT). In the described case the performance of the new technique consisting in endoscopic multiplexing transmural access (MTGT) was effective enough and led to complete recovery of the patient.

Experiment of cavitation erosion at the exit of a long orifice

Energy Technology Data Exchange (ETDEWEB)

Yagi, Yoshinori; Murase, Michio [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2002-09-01

We performed experiments to clarify mechanism of cavitation erosion and to predict cavitation erosion rate at the exit of a long orifice equipped at the chemical and volume control system in a pressurized water reactor (PWR). In order to find this mechanism, we used a high speed video camera. As the result, we observed bubble collapses near the exit of the orifice when flow condition was oscillating. So the bubble collapses due to the oscillation might cause the first stage erosion at the exit of the orifice. Using the orifice which had the cone-shaped exit, we observed that bubbles collapsed near the exit and then they collapsed at the upstream like a chain reaction. So this bubble collapse mechanism could be explained as follows: shock wave was generated by the bubble collapse near the exit, then it propagated upwards, consequently it caused the bubble collapse at the upstream. And we predicted erosion rate by evaluating the effect of the velocity and comparing the erosion resistance between the test speciment (aluminum) and the plant material (stainless steel) by means of vibratory tests. We compared the predicted erosion rate with that of the average value estimated from plant investigation, then we examined the applicability of these method to the plant evaluations. (author)

Long-term results of brachiocephalic artery percutaneous transluminal angioplasty

International Nuclear Information System (INIS)

Mc Namara, T.O.; Gardner, K.

1990-01-01

This paper establishes the ling-term and angiographic sequelae of percutaneous transluminal angioplasty (PTA) of stenoses of the origins of the brachycephalic arteries. From November of the proximal segments of the brachycephalic arteries. Clinical follow-up after PTA was 45 months. Two patients had recurrence of vertigo, after 16 and 75 months. There was no evidence of restenosis in the patient whose recurrence was after 16 months, but considerable restenosis was noted in the patient whose symptoms recurred after 75 months. That patient underwent successful repeated PTA

Orifice jet brazing process development, qualification, and initial application

International Nuclear Information System (INIS)

1971-05-01

Experiments were carried out to develop acceptable procedures for brazing molybdenum alloy orifices to fuel element channel inlets of the NERVA R-1 reactor core. Results achieved with various procedures are described, and qualification tests of the selected process are documented. The recommended procedure includes preplacing of Au-Ni-Cr alloy washers and induction heating to 1600 0 F, holding two minutes, heating further to 2400 0 F, holding one minute, and allowing to cool. Inert atmosphere is used, and fixturing maintains proper positioning of the orifices. Leak testing of the joints has demonstrated reproducibly satisfactory sealing. Repair brazing is feasible if needed. (auth)

Energy Efficiency for Biodiesel Production by Combining Two Orifices in Hydrodynamic Cavitation Reactor

Directory of Open Access Journals (Sweden)

Mahlinda Mahlinda

2014-12-01

Full Text Available Research of energy efficiency for biodiesel production process by combining two orifices on  hydrodynamic cavitation reactor had been carried out. The aim of this reseach was to studied effect of the number of orifices toward increasing temperature without using external energy source to produce biodiesel that generated by cavitation effects on orifices. The results of preliminary research showed by combining two orifices arranged in series can produce the highest thermal energy reached 48oC. Result of biodiesel production showed that yield of the highest biodiesel was 96.34% using molar ratio a methanol:oil with comparison 6:1, KOH as catalyst (1% for 50 minutes processing time. For biodiesel quality testing showed all selected parameter met the requirements of the Indonesian National Standard (SNI 04-7182:2006. Identification of biodiesel compound using GCMS showed the biodiesel compounds consisted of methyl oleate, methyl palmitate, acid linoleid, methyl stearate, palmitic acid and oleic acid with the total contents 98.39%.

Acute occlusion of the coronary artery after transluminal balloon coronary angioplasty

International Nuclear Information System (INIS)

Savchenko, A.P.; Matchin, Yu.G.; Lyakishev, A.A.

1995-01-01

The research was aimed at elucidation of the relationship of the clinical and angiographic factors, on the one hand, and development of acute occlusion following transluminal balloon coronary angioplasty TBCA, on the other. TBCA was carried out in 162 patients. Eight (4.9 %) patients developed acute occlusion of the coronary artery, which was complicated by acute myocardial infarction in 50 % cases. 35 refs.; 4 tabs

Cavitation in flow through a micro-orifice inside a silicon microchannel

Science.gov (United States)

Mishra, Chandan; Peles, Yoav

2005-01-01

Hydrodynamic cavitation in flows through a micro-orifice entrenched in a microchannel has been detected and experimentally investigated. Microfabrication techniques have been employed to design and develop a microfluidic device containing an 11.5μm wide micro-orifice inside a 100.2μm wide and 101.3μm deep microchannel. The flow of de-ionized water through the micro-orifice reveals the presence of multifarious cavitating flow regimes. This investigation divulges both similarities and differences between cavitation in micro-orifices and cavitation in their macroscale counterparts. The low incipient cavitation number obtained from the current experiments suggests a dominant size scale effect. Choking cavitation is observed to be independent of any pressure or velocity scale effects. However, choking is significantly influenced by the small stream nuclei residence time at such scales. Flow rate choking leads to the establishment of a stationary cavity. Large flow and cavitation hysteresis have been detected at the microscale leading to very high desinent cavitation numbers. The rapid transition from incipient bubbles to choking cavitation and subsequent supercavitation suggests the presence of radically different flow patterns at the microscale. Supercavitation results in a thick cavity, which extends throughout the microchannel, and is encompassed by the liquid. Cavitation at the microscale is expected to considerably influence the design of innovative high-speed microfluidic systems.

Euro-NOTES Status Paper: from the concept to clinical practice.

Science.gov (United States)

Fuchs, K H; Meining, A; von Renteln, D; Fernandez-Esparrach, G; Breithaupt, W; Zornig, C; Lacy, A

2013-05-01

The concept of natural orifice transluminal endoscopic surgery (NOTES) consists of the reduction of access trauma by using a natural orifice access to the intra-abdominal cavity. This could possibly lead to less postoperative pain, quicker recovery from surgery, fewer postoperative complications, fewer wound infections, and fewer long-term problems such as hernias. The Euro-NOTES Foundation has organized yearly meetings to work on this concept to bring it safely into clinical practice. The aim of this Euro-NOTES status update is to assess the yearly scientific working group reports and provide an overview on the current clinical practice of NOTES procedures. After the Euro-NOTES meeting 2011 in Frankfurt, Germany, an analysis was started regarding the most important topics of the European working groups. All prospectively documented information was gathered from Euro-NOTES and D-NOTES working groups from 2007 to 2011. The top five topics were analyzed. The statements of the working group activities demonstrate the growing information and changing insights. The most important selected topics were infection issue, peritoneal access, education and training, platforms and new technology, closure, suture, and anastomosis. The focus on research topics changed over time. The principle of hybrid access has overcome the technical and safety limitations of pure NOTES. Currently the following NOTES access routes are established for several indications: transvaginal access for cholecystectomy, appendectomy and colon resections; transesophageal access for myotomy; transgastric access for full-thickness small-tumor resections; and transanal/transcolonic access for rectal and colon resections. NOTES and hybrid NOTES techniques have emerged for all natural orifices and were introduced into clinical practice with a good safety record. There are different indications for different natural orifices. Each technique has been optimized for the purpose of finding a safe and realistic

Early detection of restenosis after successful percutaneous transluminal coronary angioplasty by exercise-redistribution Thallium scintigraphy

NARCIS (Netherlands)

W. Wijns (William); P.W.J.C. Serruys (Patrick); J.H.C. Reiber (Johan); P.J. de Feyter (Pim); M.J.B.M. van den Brand (Marcel); M.L. Simoons (Maarten); P.G. Hugenholtz (Paul)

1985-01-01

textabstractThe value of exercise testing and thallium scintigraphy in predicting recurrence of angina pectoris and restenosis after a primary successful transluminal coronary angioplasty (PTCA) was prospectively evaluated. In 89 patients, a symptom-limited exercise electrocardiogram (ECG) and

Detectability of Middle Mesial Root Canal Orifices by Troughing Technique in Mandibular Molars: A Micro-computed Tomographic Study.

Science.gov (United States)

Keleş, Ali; Keskin, Cangül

2017-08-01

The objective of the present study was to measure the orifice depth of middle mesial canals (MMCs) and evaluate the detectability of orifices using troughing preparation. For this study, 85 mandibular molar teeth with MMCs were selected from the scanned micro-computed tomographic images. The MMCs were categorized, and the distances between the MMC orifices and the cementoenamel junctions (CEJ) were recorded as the depth of the orifice. Data were evaluated with frequency analysis and a chi-square test using SPSS (SPSS Inc, Chicago, IL), and the results indicated a 5% significance level. It was found that 77.41% of the MMC orifices were at the CEJ level, whereas 5.38% and 9.69% of the MMC orifices were detectable within 1-mm and 2-mm depths from the CEJ, respectively. Of the specimens, 7.52% had MMC orifices deeper than 2 mm from the CEJ. Confluent anatomy was the most frequent configuration. No significant relation was detected between the orifice depth and MMC configuration (P > .05). It was concluded that 77.41% of the specimens did not require troughing preparation, the remaining 15.07% would require troughing, and 7.52% could not be accessed even with the troughing preparation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Requirements for Vertically Installed Runoff Control Boards for the “Paddy Field Dam” and Appropriate Orifice Shapes

Science.gov (United States)

Natsuki, Yoshikawa; Hideyuki, Koide; Shin-Ichi, Misawa

While the “Paddy Field Dam” project has been recognized as an effective flood control measure, there are some cases in which the runoff control boards are vertically installed on the opening of the drainage boxes without careful consideration of the orifice shape and size. The important criteria for the runoff control boards to be satisfied are: 1. to maintain a sufficient peak runoff control function, 2. to avoid excessive ponding causing overflow, 3. to minimize the influence to the ordinary water management, and 4. to reserve sufficient orifice area to avoid blockage of the orifice with floating litters. The purpose of this study is to examine proper shapes and sizes of the orifice to satisfy the criteria for the vertically installed runoff control boards through experiments and simulations. Given the condition that the orifice has sufficient area to avoid overflow with 10 and 20 year return period rainfall event (criteria 2), the simulation results show that the orifice with horizontally wider shapes has advantages over the square or circular shapes in terms of the criteria 1 and 3. The disadvantage of the horizontally wider shapes is the blockage of the orifice with floating litters (criteria 4). In conclusion, we proposed to secure sufficient vertical distance to avoid this problem by setting a lower limit on the vertical distance and then determine the widest horizontal distance to optimize all the criteria. In addition, we have constructed the “Orifice Design Assist Tool” on the basis of the examinations in this study.

CIRUGÍA ENDOSCÓPICA TRANSLUMINAL: ¡ES POSIBLE!

Directory of Open Access Journals (Sweden)

Arecio Peñaloza-Ramírez

2015-03-01

Full Text Available Introducción: La cirugía endoscópica transluminal es una técnica de ingreso a través de orificios naturales a la cavidad peritoneal y a los órganos allí contenidos, que busca disminuir los efectos adversos y las complicaciones de los procedimientos abiertos, acorde con la tendencia mundial de obtener resultados iguales a través de abordajes menos invasivos. Objetivo: Determinar las complicaciones de la cirugía endoscópica transluminal para la revisión de la cavidad peritoneal y la toma de biopsia hepática en cerdos. Metodología: Estudio experimental en 12 cerdos. Se tomó biopsia hepática transgástrica y se hizo un seguimiento durante 30 días, evaluando complicaciones y mortalidad. Al final se realizó autopsia al animal. Resultados: No se encontró mortalidad intraoperatoria. La mediana de tiempo quirúrgico fue de 84,5 minutos (RIQ 76-99. Se utilizaron para el cierre de la gastrotomía en promedio 7,8 clips (DE 3.5. En la peritoneoscopia se observó el intestino delgado, bazo, hígado y colon en la mayoría de los casos. La calidad de la biopsia hepática fue buena en 10 especímenes. La cicatrización gástrica fue adecuada en el 81.8%. Se encontraron cultivos de líquido peritoneal positivos en 9 casos. Conclusiones: La técnica requiere destreza y la peritoneoscopia es difícil por la falta de apoyo del equipo al maniobrar en retroflexión. El potencial de la técnica y el enorme beneficio para los pacientes son razones suficientes para continuar avanzando en este tipo de abordajes

Inactivation of Heterosigma akashiwo in ballast water by circular orifice plate-generated hydrodynamic cavitation.

Science.gov (United States)

Feng, Daolun; Zhao, Jie; Liu, Tian

2016-01-01

The discharge of alien ballast water is a well-known, major reason for marine species invasion. Here, circular orifice plate-generated hydrodynamic cavitation was used to inactivate Heterosigma akashiwo in ballast water. In comparison with single- and multihole orifice plates, the conical-hole orifice plate yielded the highest inactivation percentage, 51.12%, and consumed only 6.84% energy (based on a 50% inactivation percentage). Repeating treatment, either using double series-connection or circling inactivation, elevated the inactivation percentage, yet consumed much more energy. The results indicate that conical-hole-generated hydrodynamic cavitation shows great potential as a pre-inactivation method for ballast water treatment.

Renal artery blood flow assessed by video dilution technique before and after percutaneous transluminal angioplasty

International Nuclear Information System (INIS)

Lantz, B.M.T.; Link, D.P.; Lewis, E.L.; Foerster, J.M.; Lee, G.

1981-01-01

Successful percutaneous transluminal angioplasty was performed in 3 cases of renal artery stenosis where the effect upon renal blood flow was quantified by video dilution technique. This technique adds important information to pressure gradients and renin assays obtained during the dilatation procedure. (Auth.)

Transluminal endovascular stent-graft for the treatment of aortic aneurysms

Energy Technology Data Exchange (ETDEWEB)

Lee, Do Yun; Chang, Byung Chul; Shim, Won Heum; Cho, Seung Yun; Chung, Nam Sik; Kwon, Hyuk Moon; Lee, Young Joon; Lee, Jong Tae [Yonsei University College of Medicine, Seoul (Korea, Republic of)

1995-09-15

The standard treatment for aortic aneurysms is surgical replacement with a prosthetic graft. Currently there is great interest in endoluminal intervention for treatment of aortic aneurysm. The purpose of this study was to evaluate the safety and effectiveness of endoluminally placed Stent-graft for the treatment of aortic aneurysms. Transluminal endovascular Stent-graft placements were attempted in 9 patients with infra-renal aortic aneurysms(n 6), thoracic aortic aneurysm(n = 1), and aortic dissection(n = 2). The endovascular Stent-grafts were custom-designed for each patient and were constructed of self-expandable modified Gianturco Stents covered with polytetrafluroethylene. The Stent-grafts were introduced through a 16-18 French sheath and expanded to 17-30 mm in diameter. The endovascular therapy was performed using a common femoral artery cutdown with local anesthesia. The endovascular Stent-graft deployment was achieved in 7 of 9 patients. Two cases failed deployment of the Stent-graft due to iliac artery stenosis and tortousity. There were complete thrombosis of the thoracic and infra-renal aortic aneurysm surround the Stent-graft in 3 patients, and persistent leak with partial thrombosis in 2. Two patients with aortic dissection were successfully treated by obliteration of entry tears. There were no major complication associated with Stent-graft placement. These preliminary results show that transluminal endovascular Stent-grafts offer great promise and good results. Further investigation is needed to establish its long-term safety and efficacy.

Transluminal endovascular stent-graft for the treatment of aortic aneurysms

International Nuclear Information System (INIS)

Lee, Do Yun; Chang, Byung Chul; Shim, Won Heum; Cho, Seung Yun; Chung, Nam Sik; Kwon, Hyuk Moon; Lee, Young Joon; Lee, Jong Tae

1995-01-01

The standard treatment for aortic aneurysms is surgical replacement with a prosthetic graft. Currently there is great interest in endoluminal intervention for treatment of aortic aneurysm. The purpose of this study was to evaluate the safety and effectiveness of endoluminally placed Stent-graft for the treatment of aortic aneurysms. Transluminal endovascular Stent-graft placements were attempted in 9 patients with infra-renal aortic aneurysms(n 6), thoracic aortic aneurysm(n = 1), and aortic dissection(n = 2). The endovascular Stent-grafts were custom-designed for each patient and were constructed of self-expandable modified Gianturco Stents covered with polytetrafluroethylene. The Stent-grafts were introduced through a 16-18 French sheath and expanded to 17-30 mm in diameter. The endovascular therapy was performed using a common femoral artery cutdown with local anesthesia. The endovascular Stent-graft deployment was achieved in 7 of 9 patients. Two cases failed deployment of the Stent-graft due to iliac artery stenosis and tortousity. There were complete thrombosis of the thoracic and infra-renal aortic aneurysm surround the Stent-graft in 3 patients, and persistent leak with partial thrombosis in 2. Two patients with aortic dissection were successfully treated by obliteration of entry tears. There were no major complication associated with Stent-graft placement. These preliminary results show that transluminal endovascular Stent-grafts offer great promise and good results. Further investigation is needed to establish its long-term safety and efficacy

Flow and mass transfer downstream of an orifice under flow accelerated corrosion conditions

International Nuclear Information System (INIS)

Ahmed, Wael H.; Bello, Mufatiu M.; El Nakla, Meamer; Al Sarkhi, Abdelsalam

2012-01-01

Highlights: ► Mass transfer downstream of orifices was numerically and experimentally investigated. ► The surface wear pattern is measured and used to validate the present numerical results. ► The maximum mass transfer coefficient found to occur at approximately 2–3 pipe diameters downstream of the orifice. ► The FAC wear rates were correlated with the turbulence kinetic energy and wall mass transfer in terms of Sherwood number. ► The current study offered very useful information for FAC engineers for better preparation of nuclear plant inspection scope. - Abstract: Local flow parameters play an important role in characterizing flow accelerated corrosion (FAC) downstream of sudden area change in power plant piping systems. Accurate prediction of the highest FAC wear rate locations enables the mitigation of sudden and catastrophic failures, and the improvement of the plant capacity factor. The objective of the present study is to evaluate the effect of the local flow and mass transfer parameters on flow accelerated corrosion downstream of an orifice. In the present study, orifice to pipe diameter ratios of 0.25, 0.5 and 0.74 were investigated numerically by solving the continuity and momentum equations at Reynolds number of Re = 20,000. Laboratory experiments, using test sections made of hydrocal (CaSO 4 ·½H 2 O) were carried out in order to determine the surface wear pattern and validate the present numerical results. The numerical results were compared to the plants data as well as to the present experiments. The maximum mass transfer coefficient found to occur at approximately 2–3 pipe diameters downstream of the orifice. This location was also found to correspond to the location of elevated turbulent kinetic energy generated within the flow separation vortices downstream of the orifice. The FAC wear rates were correlated with the turbulence kinetic energy and wall mass transfer in terms of Sherwood number. The current study found to offer very

Microcomputed tomography analysis of mesiobuccal orifices and major apical foramen in first maxillary molars.

Science.gov (United States)

Spagnuolo, Gianrico; Ametrano, Gianluca; D'Antò, Vincenzo; Formisano, Anna; Simeone, Michele; Riccitiello, Francesco; Amato, Massimo; Rengo, Sandro

2012-01-01

Aim of the study was to determined by microcomputed tomography (µCT) the horizontal distance between the main (MB1) and the second mesiobuccal canal (MB2) orifices, the vertical distance between the MB1 and MB2 orifices planes, and the distance between the anatomic apex and major apical foramen (AF). Furthermore, we characterized the entire internal and external anatomy of the MB, distalbuccal (DB) and palatal (P) maxillary first molars roots. Twenty-two intact extracted first maxillary molars were scanned by X-ray computed transaxial µCT and then 2D and 3D images were processed and analyzed. The results showed that 77.27% of the mesiobuccal (MB) roots presented a second MB canal, and 29.41% of the MB2 were independent from the MB1 canals. In 15 teeth, there were three root canal orifices on the chamber floor, and 10 of these teeth presented MB2 canals. The mean vertical distance between the MB1 and MB2 planes was 1.68 ± 0.83 mm. Seven teeth had four orifices. The mean horizontal interorificial distance between the MB1 and MB2 orifices was 1.21 ± 0.5 mm. Accessory canals were observed in 33.33% of the roots, loops in 6.06%, while isthmuses were found in 15 of the 22 MB roots. Of the total roots, 74.24% presented one foramen, while all of the roots showed a major apical foramen that was not coincident with the anatomic apex. Our µCT analysis provided interesting features on the horizontal and vertical distance between the MB1 and MB2 orifices and on the distance of AF and anatomic apex. These results have an important clinical value because might support the endodontist in the recruitment, negotiation and obturation of maxillary first molar canal system.

Impact of valve prosthesis-patient mismatch estimated by echocardiographic-determined effective orifice area on long-term outcome after aortic valve replacement.

Science.gov (United States)

Florath, Ines; Albert, Alexander; Rosendahl, Ulrich; Ennker, Ina Carolin; Ennker, Jrgen

2008-06-01

The impact of valve prosthesis-patient mismatch on long-term outcome after aortic valve replacement estimated by various variables such as projected indexed effective orifice area and internal geometric orifice area obtained from in vivo or in vitro published data is still controversial. The effective orifice area was measured by echocardiography in 533 patients. The mean age of the patients was 71 +/- 9 years; mean follow-up time was 4.7 +/- 2.2 years. The impact of severe (indexed effective orifice area regression. Severe mismatch (hazard ratio: 1.9 [1.08-3.21]) was a significant predictor of survival time after adjustment for age, left ventricular ejection fraction, atrial fibrillation, New York Heart Association class, serum creatinine, and hemoglobin level. The 5- and 7-year survival rates were 71% +/- 4% and 54% +/- 8% for patients with severe mismatch and 83% +/- 4% and 80% +/- 8% for patients with mild mismatch, respectively. The correlation between projected and measured indexed effective orifice area was of medium strength (r = 0.49), and the frequency of observed mismatch depended linearly on the projected indexed effective orifice area. Although projected indexed effective orifice area and indexed internal geometric orifice area were significant predictors of severe mismatch, the sensitivity and specificity for severe prosthesis-patient mismatch were only 75% and 52%, using an optimal threshold of projected indexed effective orifice area defined by the Youden index. Severe prosthesis-patient mismatch estimated by effective orifice area measured within 10 days was an independent risk factor of survival time. Projected indexed effective orifice area determined at surgery does not sufficiently predict mismatch.

Transgastric endoluminal gastrojejunostomy: technical development from bench to animal study (with video).

Science.gov (United States)

Chiu, Philip Wai Yan; Wai Ng, Enders Kwok; Teoh, Anthony Yun Bun; Lam, Candice Chuen Hing; Lau, James Yun Wong; Sung, Joseph Jao Yiu

2010-02-01

Gastrojejunal anastomosis is commonly performed for palliative management of malignant gastric outlet obstruction and bariatric surgery. Natural orifice transluminal endoscopic surgery revolutionized the surgical approach to intra-abdominal surgery. This study explored the possibility of performing gastrojejunostomy (GJ) by using a hybrid natural orifice transluminal endoscopic surgery approach. To develop a surgical technique for the performance of transgastric endoscopic GJ (TGEJ) in a porcine model. Prospective series of animal experiments. University hospital animal laboratory. Thirteen female domestic pigs. With the animals under general anesthesia, the endoscope is passed through the gastrotomy and a segment of small bowel is retrieved into the stomach. An enterotomy is then created, and an EndoGIA stapler is introduced through an intragastric port and passed between the small bowel and stomach wall. A GJ is formed after firing of the EndoGIA stapler. The pigs are allowed to resume their diet 1 day after the operation and are allowed to survive for 2 weeks before they are euthanized. The patency of the GJ is confirmed with a repeat endoscopy, contrast study, and postmortem examination. A total of 13 TEGJs were performed, 11 of which were successful. The mean operative time was 53.6 +/- 45.7 minutes. The mean time for gastrotomy was 4.7 minutes, and that for GJ was 42.5 minutes. One TEGJ was converted to open surgery because of malpositioning of the intragastric port, and the other failed because the enterotomy was too extensive. Ten of 11 pigs survived for 2 weeks, and endoscopic examination with contrast study confirmed that all the gastrojejunostomies were patent. On postmortem examination, the average size of the GJ was 30 mm. The length between duodenojejunal flexure and the site chosen to perform the GJ could not be determined. TEGJ is technically feasible with a patent and sizable anastomosis.

Development of honeycomb type orifices for flow zoning in PFBR

Energy Technology Data Exchange (ETDEWEB)

Pandey, G.K., E-mail: gkpandey@igcar.gov.in; Ramdasu, D.; Padmakumar, G.; Prakash, V.; Rajan, K.K.

2013-09-15

Highlights: • Cavitation free flow zoning devices are developed for reactor core in PFBR. • These devices are experimentally investigated for their hydraulic characteristics. • Pressure drop and cavitation are two main characteristics to be investigated. • Various configurations of devices utilized in different zones are discussed. • Loss coefficient for each configuration is compared and reported. -- Abstract: The prototype fast breeder reactor (PFBR) is in its advanced phase of construction at Kalpakkam, India. It is a sodium cooled, pool type reactor with two loop concept where each loop have one primary sodium pump (PSP), one secondary sodium pump (SSP) and two intermediate heat exchangers (IHX). PFBR core subassemblies (SA) are supported vertically inside the sleeves provided in the grid plate (GP). The GP acts as a coolant header through which flow is distributed among the SA to remove fission heat. Since the power profile of the reactor core is not uniform, it is necessary to distribute the coolant flow (called flow zoning) to each subassembly according to their power levels to get maximum mean outlet temperature of sodium at core outlet. To achieve this, PFBR core is divided into 15 zones such as fuel, blanket, reflector, storage, etc. according to their respective power levels. The flow zoning in the different SAs of the reactor core is achieved by installing permanent pressure dropping devices in the foot of the subassembly. Orifices having honey-comb type geometry were developed to meet the flow zoning requirements of fuel zone. These orifices being of very complex geometry requires precision methods of manufacturing to achieve the desired shape under specified tolerances. Investment casting method was optimized to manufacture this orifice plate successfully. Hydraulics of these orifices is important in achieving the required pressure drop without cavitation. The pressure drop across these orifice geometries depends mainly on geometrical

Percutaneous transluminal rotational atherectomy in the treatment of peripheral vascular disease using a transluminal endatherectomy catheter (TEC): Initial results and angiographic follow-up

International Nuclear Information System (INIS)

Rilinger, Norbert; Goerich, Johannes; Scharrer-Pamler, Reinhard; Vogel, Jochen; Tomczak, Reinhard; Merkle, Elmar; Sokiranski, Roman; Brambs, Hans-Juergen

1997-01-01

Purpose. To evaluate the clinical results of percutaneous transluminal rotational atherectomy in the treatment of peripheral vascular disease. Methods. Rotational atherectomy was performed in 39 patients aged 39-87 years (mean 66.6 years). A total of 71 lesions (43 stenoses and 28 occlusions) were treated in 40 limbs. Additional balloon angioplasty was required in 54% of lesions. Fifteen patients (37.5%) presented in Fontaine stage II, 10 patients (25%) in Fontaine stage III and 15 patients (37.5%) in Fontaine stage IV. Rotational atherectomy at 750 rpm was carried out over a 0.014-inch guidewire with continuous aspiration into a vacuum, bottle. Follow-up angiography and color flow Doppler examinations were performed in 22 patients (23 limbs) after a mean period of 6 months (range 2-14 months). Results. There was one primary technical failure. In 36 of 40 lesions there was a good angiographic result with residual stenoses in less than 30%. In 70 lesions treated by rotational atherectomy, however, 54% showed residual stenoses of 30%-50% and these cases required additional balloon angioplasty. The mean ankle-brachial index improved significantly (p<0.001), from 0.49 before the procedure to 1.01 after the procedure. A single distal embolus, related to primary recanalization, occurred and there were two large inguinal hematomas. Cumulative clinical patency after 6 months was 83.8% and cumulative angiographic patency after 6 months was 79.1%. Conclusion. Percutaneous rotational atherectomy is a promising approach for the treatment of chronic peripheral vascular disease. Further prospective, randomized studies are necessary to compare percutaneous transluminal angioplasty with this new technical approach

The impact assessment of eccentric installation and roughness change in piping on the orifice flow measurement

International Nuclear Information System (INIS)

Nishi, Y.; Eguchi, Y.; Nishihara, T.; Kanai, T.; Kondo, M.

2012-01-01

In orifice flowmeters used in nuclear power plants, requirements for the inner surface roughness of upstream piping and eccentric installation exist depending on certain standards. If these cannot be satisfied based on the installation condition, an appropriate error margin must be considered, although this remains to be clarified. In this research, quantitative data concerning the relative error of orifice flowmeters were obtained during experiments with the parameters of the inner surface roughness of upstream piping and the installation eccentricity of the orifice hole. The maximum Reynolds number of the experimental facility is about 1.6x10 6 . In orifice flowmeters, the flow rate is calculated based on the differential pressure between upstream and downstream orifices and the peculiar discharge coefficient C. The latter value shows an upward trend with increasing roughness of piping, while change of 0.3% of C was observed in terms of roughness (case 2), which approaches the limits of the JIS standard. With significant roughness (Case 3) that exceeds five times the JIS standard, C is shown to have increased by about 1%. No influence was observed by varying the direction of eccentric installation, hence this was fixed and the amount of eccentricity was considered. Change in C of about 0.25% was observed when around twice the standard level of eccentricity was applied. The error margin data under conditions exceeding the JIS standard for the orifice flowmeter was obtained. (authors)

Technological advances in robotic-assisted laparoscopic surgery.

Science.gov (United States)

Tan, Gerald Y; Goel, Raj K; Kaouk, Jihad H; Tewari, Ashutosh K

2009-05-01

In this article, the authors describe the evolution of urologic robotic systems and the current state-of-the-art features and existing limitations of the da Vinci S HD System (Intuitive Surgical, Inc.). They then review promising innovations in scaling down the footprint of robotic platforms, the early experience with mobile miniaturized in vivo robots, advances in endoscopic navigation systems using augmented reality technologies and tracking devices, the emergence of technologies for robotic natural orifice transluminal endoscopic surgery and single-port surgery, advances in flexible robotics and haptics, the development of new virtual reality simulator training platforms compatible with the existing da Vinci system, and recent experiences with remote robotic surgery and telestration.

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.

Effect of sleep-inducing music on sleep in persons with percutaneous transluminal coronary angiography in the cardiac care unit.

Science.gov (United States)

Ryu, Min-Jung; Park, Jeong Sook; Park, Heeok

2012-03-01

The study compared the effect of earplug-delivered sleep-inducing music on sleep in persons with percutaneous transluminal coronary angiography in the cardiac care unit. Diverse types of music have been claimed to improve sleeping elsewhere, but relatively little is known in South Korea. Most studies investigating the effect of sleep-inducing music on sleep have involved persons with insomnia, even though many persons with cardiovascular disease in the intensive care unit suffer from sleeping problems. There is a need to investigate the effect of sleep-inducing music on sleep disorders in persons with percutaneous transluminal coronary angiography in the cardiac care unit. An experimental research design was used. Data collection was conducted in the cardiac care unit of K University Hospital in D city, from 3 September-4 October 2010. Fifty-eight subjects participated and were randomly assigned to the experimental group (earplug-delivered sleep-inducing music for 52 min beginning at 10:00 pm, while wearing an eyeshield, n = 29) and the control group (no music, but earplugs and eyeshield worn, n = 29). The quantity and quality of sleep were measured using questionnaires at 7 am the next morning for each group. Participants in the experimental group reported that the sleeping quantity and quality were significantly higher than control group (t = 3·181, p = 0·002, t = 5·269, p music significantly improved sleep in patients with percutaneous transluminal coronary angiography at a cardiac care unit. Offering earplugs and playing sleep-inducing music may be a meaningful and easily enacted nursing intervention to improve sleep for intensive care unit patients. Nurses working at cardiac care unit can use music to improve sleeping in clients with percutaneous transluminal coronary angiography. © 2011 Blackwell Publishing Ltd.

Case report: renovascular hypertension following radiotherapy and chemotherapy treated by transluminal angioplasty

International Nuclear Information System (INIS)

Minton, M.J.; McIvor, J.; Cappuccio, F.P.; MacGregor, G.A.; Newlands, E.S.

1986-01-01

A man aged 33 with poorly controlled hypertension who had been treated with radiotherapy and combination chemotherapy for testicular teratoma 8 years earlier was found on arteriography to have 75% stenosis of the left renal artery and occlusion of the right renal artery. The stenosis was dilated by transluminal angioplasty and the hypertension adequately controlled. Patients who develop high blood pressure after abdominal radiotherapy with or without chemotherapy should be investigated for renal artery stenosis. (author)

Mass transfer coefficient in disturbed flow due to orifice for flow accelerated corrosion in nuclear power plant

International Nuclear Information System (INIS)

Prasad, Mahendra; Gaikwad, Avinash J.; Sridharan, Arunkumar; Parida, Smrutiranjan

2015-01-01

The flow of fluid in pipes cause corrosion wherein the inner surface of pipe becomes progressively thinner and susceptible to failure. This form of corrosion dependent on flow dynamics is called Flow Accelerated Corrosion (FAC) and has been observed in Nuclear Power Plants (NPPs). Mass transfer coefficient (MTC) is related to extent of wall thinning and it changes from its value in a straight pipe (with same fluid parameters) for flow in orifices, bends, junctions etc. due to gross disturbance of the velocity profile. This paper presents two-dimensional computational fluid dynamics (CFD) simulations for an orifice configuration in a straight pipe. Turbulent model K- ω with shear stress transport and transition flow was the model used for simulation studies. The mass transfer boundary layer (MTBL) thickness δ mtbl is related to the Schmidt number (Sc) and hydrodynamic boundary layer thickness δ h , as δ mtbl ~ δh/(Sc 1/3 ). MTBL is significantly smaller than δ h and hence boundary layer meshing was carried out deep into δ mtbl . Uniform velocity profile was applied at the inlet. Post orifice fluid shows large recirculating flows on the upper and lower wall. At various locations after orifice, mass transfer coefficient is calculated and compared with the value in straight pipe with fully developed turbulent flow. The MTC due to the orifice increases and it is correlated with enhanced FAC in region after orifice. (author)

Numerical simulation of progressive BWR fuel inlet orifices

International Nuclear Information System (INIS)

Sara Lundgren; Hernan Tinoco; Aleksander Pohl; Wiktor Frid

2005-01-01

Full text of publication follows: A 'progressive' orifice is characterized by an edge-shaped hole that gives a Reynolds number dependent resistance coefficient. For Reynolds numbers smaller than a critical one, the resistance coefficient has a high constant value that drops to a much lower value for Reynolds numbers greater than this critical value. A similar effect is widely known for external flows around bodies of different shapes, i. e. spheres, cylinders, etc., and the sudden drop in drag coefficient is due to the shift from laminar to turbulent boundary-layer flow. Experimentally, progressive orifices have been investigated under high-pressure and high-temperature conditions by Akiba et al. (2001) for a reduced set of geometrical parameters. Using the sparse experimental data, a core stability study was carried out by Forsmaks Kraftgrupp AB that showed an improvement in core stability but without the expected reduction in pump power at normal operation. The reason for this partial success was the impossibility of optimizing the fuel inlet pressure drop owing to the limited amount of available data. Due to the high costs associated with the experimental generation of high-pressure, high-temperature data, it was considered that, if possible, the lacking data could be generated numerically at much lower cost. Therefore, the present work deals with the possibility of numerically simulate the flow through progressive orifices, and with the conditions under which to reproduce and generate resistance coefficient data by means of a commercial CFD-code. The results obtained with a two-dimensional, axisymmetric approximation show that Reynolds Averaged Navier-Stokes (RANS) turbulence models are able to qualitatively capture the physics of the phenomenon but with an earlier transition to turbulent boundary-layer flow and with an underestimation of the resistance coefficient by approximately 20 %. This underestimation of the resistance coefficient is related to the two

Numerical simulation of progressive BWR fuel inlet orifices

Energy Technology Data Exchange (ETDEWEB)

Sara Lundgren; Hernan Tinoco [Forsmarks Kraftgrupp AB, 742 03 Oesthammar (Sweden); Aleksander Pohl; Wiktor Frid [The Royal Institute of Technology, Dept. Energy Technology, SE-100 44 Stockholm (Sweden)

2005-07-01

Full text of publication follows: A 'progressive' orifice is characterized by an edge-shaped hole that gives a Reynolds number dependent resistance coefficient. For Reynolds numbers smaller than a critical one, the resistance coefficient has a high constant value that drops to a much lower value for Reynolds numbers greater than this critical value. A similar effect is widely known for external flows around bodies of different shapes, i. e. spheres, cylinders, etc., and the sudden drop in drag coefficient is due to the shift from laminar to turbulent boundary-layer flow. Experimentally, progressive orifices have been investigated under high-pressure and high-temperature conditions by Akiba et al. (2001) for a reduced set of geometrical parameters. Using the sparse experimental data, a core stability study was carried out by Forsmaks Kraftgrupp AB that showed an improvement in core stability but without the expected reduction in pump power at normal operation. The reason for this partial success was the impossibility of optimizing the fuel inlet pressure drop owing to the limited amount of available data. Due to the high costs associated with the experimental generation of high-pressure, high-temperature data, it was considered that, if possible, the lacking data could be generated numerically at much lower cost. Therefore, the present work deals with the possibility of numerically simulate the flow through progressive orifices, and with the conditions under which to reproduce and generate resistance coefficient data by means of a commercial CFD-code. The results obtained with a two-dimensional, axisymmetric approximation show that Reynolds Averaged Navier-Stokes (RANS) turbulence models are able to qualitatively capture the physics of the phenomenon but with an earlier transition to turbulent boundary-layer flow and with an underestimation of the resistance coefficient by approximately 20 %. This underestimation of the resistance coefficient is related to

Percutaneous transluminal angioplasty (PTA) of supra-aortic arteries especially the internal carotid artery

Energy Technology Data Exchange (ETDEWEB)

Kachel, R.; Basche, S. (Medizinische Akademie, Erfurt (Germany, F.R.). Radiologische Klinik); Heerklotz, I.; Grossmann, K. (Medizinische Akademie, Erfurt (Germany, F.R.). Klinik fuer Innere Medizin); Endler, S. (Medizinische Akademie, Erfurt (Germany, F.R.). Klinik fuer Neurologie und Psychiatrie)

1991-06-01

We present our experience with 105 patients in whom percutaneous transluminal angioplasty was performed in 112 stenosed or occluded supra-aortic arteries. Symtoms of cerebrovascular and/or vertebrobasilar insufficiency were present in 104 of the 105 patients. The angioplasty was successful in 35 stenoses of the internal carotid artery, 2 stenoses of the common carotid artery, 1 stenosis of the external carotid artery, 15 stenoses of the vertebral artery, 3 stenoses of the innominate artery and 44 stenoses of the subclavian artery. There were only 4 minor-complications (2 haematomas, 1 transient ischemic attack, 1 small thrombus of the internal carotid artery which was detected by 111-indium platelet scintigraphy and treated by thrombendarterectomy before the appearance of neurological symptoms). All patients were symptom free after angioplasty. During the observations period of 3 to 109 months (average 58 months) there were only two cases with re-stenosis after subclavian angioplasty. The results of more than 700 personal and international published percutaneous transluminal angioplasties of supra-aortic arteries are presented. The results suggest that angioplasty of supra-aortic arteries is an effective method. On strict definition of the indications, the complication rate for angioplasty of the supra-aortic arteries is not likely to be higher than that for operative treatment. (orig.).

Organic compounds generated after the flow of water through micro-orifices: Were they synthesized?

Directory of Open Access Journals (Sweden)

Tomiichi Hasegawa

2017-08-01

Full Text Available Micro-fluid mechanics is an important area of research in modern fluid mechanics because of its many potential industrial and biological applications. However, the field is not fully understood yet. In previous work, when passing ultrapure water (UPW in which air was dissolved (UPW* through micro-orifices, we found that the flow velocity decreased and stopped over time, and membranes were frequently formed in the orifice when the flow stopped. The membrane came from the dissolved air in UPW*, and membrane formation was closely related to electric charges generated in orifices by the flow. In the present paper, we clarified the components of the membrane and suggested a mechanism for membrane formation. We examined the effect of contaminants on the membrane formation and confirmed our previous results. We identified the chemical components of the membrane and those present in the UPW* itself by using an electron probe microanalyzer and found that the proportion of each element differed between the membrane and UPW*. Raman and infrared (IR spectroscopy showed that the membrane consisted of organic substances such as carotenoids, amides, esters, and sugars. We irradiated UPW* with ultraviolet light to cut organic chains that may be left in UPW* as contaminants. We found a similar membrane and organic compounds as in nonirradiated UPW*. Furthermore, although the UPW that was kept from contact with air after it was supplied from the UPW maker (UPW0 and bubbled with Ar gas (UPW0 bubbled with Ar formed no membrane, the UPW0 bubbled with CO2 formed thin membranes, and Raman and IR analysis showed that this membrane contained carboxylic acid salts, carotenoids, or a mixture of both. We found that electric grounding of the orifice reduces the probability of membrane formation and that the jets issuing from an aperture bear negative charges, and we assumed that the micro-orifices possess positive charges generated by flows. Consequently, we suggest that

Performance of an Orifice Compensated Two-Lobe Hole-Entry Hybrid Journal Bearing

Directory of Open Access Journals (Sweden)

J. Sharana Basavaraja

2008-01-01

Full Text Available The work presented in this paper aims to study the performance of a two-lobe hole-entry hybrid journal bearing system compensated by orifice restrictors. The Reynolds equation governing the flow of lubricant in the clearance space between the journal and bearing together with the equation of flow through an orifice restrictor has been solved using FEM and Galerkin's method. The bearing performance characteristics results have been simulated for an orifice compensated nonrecessed two-lobe hole-entry hybrid journal bearing symmetric configuration for the various values of offset factor (, restrictor design parameter (2, and the value of external load (0. Further, a comparative study of the performance of a two-lobe hole-entry hybrid journal bearing system with a circular hole-entry symmetric hybrid journal bearing system has also been carried out so that a designer has a better flexibility in choosing a suitable bearing configuration. The simulated numerical results indicate that for the two-lobe symmetric hole-entry hybrid journal bearing system with an offset factor ( greater than one provides 30 to 50 percent larger values of direct stiffness and direct damping coefficients as compared to a circular symmetric hole-entry hybrid journal bearing system.

Transluminal coronary angioplasty (TCA) techniques, indications and results

International Nuclear Information System (INIS)

Kober, G.; Lang, H.; Vallbracht, C.; Bussmann, W.D.; Hopf, R.; Kunkel, B.; Kaltenbach, M.

1985-01-01

Transluminal coronary angioplasty (TCA) was introduced in 1977 for dilatation of coronary stenoses. From October 1977 to December 1984 1087 procedures have been performed in Frankfurt. The mean success rate was 77% with an increase from 58% to 84% since 1977. Recurrences were seen within the first year in 15% of the patients, which could be treated successfully in a high percentage with a second TCA. Emergency bypass operations were necessary in 5.2%. Four patients (fatality rate 0.37%) died as the consequence of the intervention. Within few years TCA has become an established procedure for myocardial revascularisation, with a high success rate. Major progress has been possible in the last few years due to technical developments, which are still going on. They may lead to further improvement of the results and enlargement of the indication for TCA. (orig.) [de

Short-, medium-, and long-term follow-up after percutaneous transluminal coronary angioplasty for stable and unstable angina pectoris

NARCIS (Netherlands)

O. Kamp (Otto); K.J. Beatt (Kevin); P.J. de Feyter (Pim); M.J.B.M. van den Brand (Marcel); H. Suryapranata (Harry); H.E. Luijten; P.W.J.C. Serruys (Patrick)

1989-01-01

textabstractThe first 840 consecutive patients who underwent percutaneous transluminal coronary angioplasty (PTCA) performed in the same institution were retrospectively assessed at an average follow-up period of 25 months after the initial procedure. The study population consisted of 506 patients

Exploring the umbilical and vaginal port during minimally invasive surgery.

Science.gov (United States)

Tinelli, Andrea; Tsin, Daniel A; Forgione, Antonello; Zorron, Ricardo; Dapri, Giovanni; Malvasi, Antonio; Benhidjeb, Tahar; Sparic, Radmila; Nezhat, Farr

2017-09-01

This article focuses on the anatomy, literature, and our own experiences in an effort to assist in the decision-making process of choosing between an umbilical or vaginal port. Umbilical access is more familiar to general surgeons; it is thicker than the transvaginal entry, and has more nerve endings and sensory innervations. This combination increases tissue damage and pain in the umbilical port site. The vaginal route requires prophylactic antibiotics, a Foley catheter, and a period of postoperative sexual abstinence. Removal of large specimens is a challenge in traditional laparoscopy. Recently, there has been increased interest in going beyond traditional laparoscopy by using the navel in single-incision and port-reduction techniques. The benefits for removal of surgical specimens by colpotomy are not new. There is increasing interest in techniques that use vaginotomy in multifunctional ways, as described under the names of culdolaparoscopy, minilaparoscopy-assisted natural orifice surgery, and natural orifice transluminal endoscopic surgery. Both the navel and the transvaginal accesses are safe and convenient to use in the hands of experienced laparoscopic surgeons. The umbilical site has been successfully used in laparoscopy as an entry and extraction port. Vaginal entry and extraction is associated with a lower risk of incisional hernias, less postoperative pain, and excellent cosmetic results.

Robotic laparoendoscopic single-site surgery: From present to future

Directory of Open Access Journals (Sweden)

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.

Evaluation of the flow-accelerated corrosion downstream of an orifice. 1. Measurements and numerical analysis of flow field

International Nuclear Information System (INIS)

Utanohara, Yoichi; Nagaya, Yukinori; Nakamura, Akira; Murase, Michio

2008-01-01

In this study, in order to evaluate the effects of flow field on corrosion rate due to flow accelerated corrosion (FAC), an orifice flow was measured and calculated. The diameter of pipe is 50 mm and that of the orifice is 24.3 mm, and flow velocity in a water loop was set at 2.41 m/s. Flow field was measured by laser Doppler velocimetry (LDV) and particle image velocimetry (PIV), and compared with a calculation for the same flow conditions. Measurements of wall shear stress downstream of the orifice was also planed. The calculated velocity distribution of standard k-□ agreed qualitatively with PIV data and quantitatively with LDV data. Instantaneous flow field measured by PIV showed vortices around the jet from the orifice and some of them reached near the pipe wall. (author)

Pressure heat pumping in the orifice pulse-tube refrigerator

International Nuclear Information System (INIS)

Boer, P.C.T. de

1996-01-01

The mechanism by which heat is pumped as a result of pressure changes in an orifice pulse-tube refrigerator (OPTR) is analyzed thermodynamically. The thermodynamic cycle considered consists of four steps: (1) the pressure is increased by a factor π 1 due to motion of a piston in the heat exchanger at the warm end of the regenerator; (2) the pressure is decreased by a factor π 2 due to leakage out of the orifice; (3) the pressure is further decreased due to motion of the piston back to its original position; (4) the pressure is increased to its value at the start of the cycle due to leakage through the orifice back into the pulse tube. The regenerator and the heat exchangers are taken to be perfect. The pressure is assumed to be uniform during the entire cycle. The temperature profiles of the gas in the pulse tube after each step are derived analytically. Knowledge of the temperature at which gas enters the cold heat exchanger during steps 3 and 4 provides the heat removed per cycle from this exchanger. Knowledge of the pressure as a function of piston position provides the work done per cycle by the piston. The pressure heat pumping mechanism considered is effective only in the presence of a regenerator. Detailed results are presented for the heat removed per cycle, for the coefficient of performance, and for the refrigeration efficiency as a function of the compression ratio π 1 and the expansion ratio π 2 . Results are also given for the influence on performance of the ratio of specific heats. The results obtained are compared with corresponding results for the basic pulse-tube refrigerator (BPTR) operating by surface heat pumping

A Systematic Review of Outcomes Following Percutaneous Transluminal Angioplasty and Stenting in the Treatment of Transplant Renal Artery Stenosis

NARCIS (Netherlands)

Ngo, A. T.; Markar, S. R.; de Lijster, M. S.; Duncan, N.; Taube, D.; Hamady, M. S.

2015-01-01

To evaluate outcomes following treatment of transplant renal artery stenosis by percutaneous transluminal angioplasty and stent insertion. A literature search was performed using Pubmed, MEDLINE, Embase, Wiley Interscience and the Cochrane Library databases. Outcome measures were glomerular

A perspective of percutaneous transluminal angioplasty.

Science.gov (United States)

Stanson, A W

1983-01-01

PTA is a relatively new procedure which is still evolving. More technical improvements are needed. Stiffer balloon plastics and devices to measure arterial wall compliance during balloon inflation are predicted to lead to better long-term success rates. Increasing case numbers provide greater expertise and subsequent refinements in performance and case selection. These factors will lead to improved statistics. Other features of overall patient care must be considered also. The procedure is easy for patients to tolerate, and they can return to activities and work in three or four days. The overall cost is much cheaper than surgery, even at a conservative success rate of 65 percent. There is minimal risk and morbidity, and virtually no mortality. PTA can be repeated if the lesion recurs. Severe complications are rare and almost always surgically treatable. If PTA fails to achieve success, a traditional surgical procedure can be performed. Percutaneous transluminal angioplasty is an important therapeutic alternative to traditional medical and surgical treatment for occlusive arterial disease. It can save legs, veins, time, and money. We need to refine and accurately record the use of this procedure. Total cooperation among clinicians, surgeons, and radiologists is essential for proper utilization of PTA.

Numerical simulation of progressive inlet orifices in boiling water reactor fuel

International Nuclear Information System (INIS)

Lundgren, Sara

2004-07-01

This thesis was carried out at Forsmark Nuclear Power Plant. The power plant in Forsmark consists of three boiling water reactors (BWR) which produce about 17% of Swedish electricity. In a BWR the nuclear reactions are used to boil water inside the reactor vessel. The water works both as a coolant and as a moderator and the resulting steam is used directly to run the turbines. A problem when running a BWR at low flow conditions is the density wave oscillations that might occur to the water flow inside the fuel assemblies. These oscillations arise due to the connection between power and flow rate in a heated channel with two-phase flow. In order to improve the stability performance of the channel an orifice plate is placed at the inlet of each fuel assembly. Today these orifice plates have sharp edges and a constant resistance coefficient. Experimental work has been done with progressive orifices, the edge of which is half-oval in shape. The advantage of progressive orifices is the lower pressure losses with an increase of the Reynolds number, a similar phenomenon that appears in external flow around curved bodies. Since there are high costs associated with experimental generation of high- temperature and high-pressure data, it is of some interest to be able to reproduce and generate data using Computational Fluid Dynamics (CFD). This work deals with the possibility to use the CFD-code Fluent to do numerical simulations of the flow through progressive orifices. The following conclusions may be drawn from the numerical results: All simulations using Reynolds-Averaged Navier-Stokes (RANS) turbulence models, two-dimensional and three-dimensional, capture an abrupt decrease of the resistance coefficient at higher Reynolds numbers. Two-equation models seem to under-predict the critical Reynolds number. The five-equation Reynolds Stress Model (RSM) gives a critical Reynolds number of the same order of magnitude of that measured in experiments. No major differences have

Mechanisms of natural ventilation in livestock buildings

DEFF Research Database (Denmark)

Rong, Li; Bjerg, Bjarne; Batzanas, Thomas

2016-01-01

Studies on the mechanisms of natural ventilation in livestock buildings are reviewed and influences on discharge and pressure coefficients are discussed. Compared to studies conducted on buildings for human occupation and industrial buildings which focus on thermal comfort, ventilation systems......, indoor air quality, building physics and energy etc., our understanding of the mechanisms involved in natural ventilation of livestock buildings are still limited to the application of the orifice equation. It has been observed that the assumptions made for application of the orifice equation...... are not valid for wind-induced cross ventilation through large openings. This review identifies that the power balance model, the concept of stream tube and the local dynamic similarity model has helped in the fundamental understanding of wind-induced natural ventilation in buildings for human occupation...

Ruptured Splenic Abscess following Percutaneous Transluminal Angioplasty in a 40-Year-Old Man

Directory of Open Access Journals (Sweden)

C. Rajasekharan

2012-05-01

Full Text Available The incidence of splenic abscesses is currently 0.14–0.7% with a reported mortality of 0–47%. The diagnosis of splenic abscess which has ruptured into the abdomen is often overlooked because of its rarity and its misleading clinical presentations. Percutaneous coronary interventions (PCIs and coronary stenting procedures increased from 184,000 to 885,000 (from 335 to 1,550 and from 3,000 to 770,000 (from 5 to 1,350 per one million inhabitants, respectively. A 40-year-old Asian male presented to our emergency department with upper abdominal pain 5 days after a percutaneous transluminal coronary angioplasty. Clinical examination raised the possibilities of acute pancreatitis and intraabdominal sepsis. An initial ultrasound of the abdomen and blood tests were negative. A computed tomography scan of the abdomen revealed a splenic abscess that had ruptured into the abdomen. Pus culture revealed a multidrug-resistant strain of Klebsiella pneumoniae that was sensitive to meropenem. The patient recovered quickly after open surgical drainage and antibiotic therapy. As this is the second case of splenic abscess and the first case report of a ruptured splenic abscess following a PCI, it will be rational to administer a short course of antibiotic prophylaxis for high-risk immunocompromised patients who are undergoing percutaneous transluminal coronary intervention.

Software development for a orifice plate characterization used in the oil and gas industry; Desenvolvimento de um 'software' para caracterizacao de placas de orificio utilizadas na industria do petroleo

Energy Technology Data Exchange (ETDEWEB)

Andreas, N. Andreas [Universidade Federal de Itajuba (UNIFEI), MG (Brazil)

2008-07-01

The petroleum industry is an economic area that has a strong impact, because this, the information precision is one of the most important facts and it is able to be defined with software simulation. The knowledge of the exactly quantify of petroleum is fundamental, and then the instrumentation is essential for this measurement. There are many mechanisms to measure the volume flow, and one of the most used is the Orifice Plates, which has been more common in the Natural Gas Industry. The software development goal is the characterization of these Orifice Plates, allowing that the constant, which characterizes certain Plate, to be determined without Labor instruments, for that the software has an actualized database. But, the software needs some variables, that are responsible for the environment characteristics and the used material, to calculate the constant of the Orifice Plate, for example, fluid viscosity, environment temperature and kind of the Orifice Plate. The utilized equations in this software are based on the Stolz II equations. This tool is able to facilitate the work in petroleum industry, besides it is done for mobile applications, allowing analyses in real time. (author)

Association Between Disruption of Fibrin Sheaths Using Percutaneous Transluminal Angioplasty Balloons and Late Onset of Central Venous Stenosis

International Nuclear Information System (INIS)

Ni, Nina; Mojibian, Hamid; Pollak, Jeffrey; Tal, Michael

2011-01-01

To compare the rates of central venous stenosis in patients undergoing hemodialysis who underwent disruption of fibrin sheath with percutaneous transluminal angioplasty balloons and those who underwent over-the-wire catheter exchange. This study is a retrospective review of 209 percutaneous transluminal angioplasty balloon disruption and 1304 over-the-wire catheter exchange procedures performed in 753 patients. Approval from the Human Investigations Committee was obtained for this study. Up to 10-year follow-up was performed. A χ 2 test was used to compare the rates of central venous stenosis after balloon disruption versus catheter exchange. A t-test was used to compare time to central venous stenosis development. Of the 753 patients in the study, 127 patients underwent balloon disruption of fibrin sheath and 626 had catheter exchange. Within the balloon disruption group, 18 (14.2%) of 127 patients subsequently developed central venous stenosis, compared with 44 (7.0%) of 626 in the catheter exchange group (P 2 test). Time to central venous stenosis development was approximately 3 years in both groups and not significantly different (1371 and 1010 days, P = 0.20). A total of 25.2% of patients in the balloon disruption group had four or more subsequent catheter exchanges, versus 12.6% in the catheter exchange group (P 2 test). In conclusions, there is a possible association between percutaneous transluminal angioplasty balloon disruption of fibrin sheath and late-onset central venous stenosis. Because venography was not routinely performed in catheter exchange patients, future randomized studies are necessary to confirm these findings.

Shear flow over a plane wall with an axisymmetric cavity or a circular orifice of finite thickness

International Nuclear Information System (INIS)

Pozrikidis, C.

1994-01-01

Shear flow over a plane wall that contains an axisymmetric depression or pore is studied using a new boundary integral method which is suitable for computing three-dimensional Stokes flow within axisymmetric domains. Numerical results are presented for cavities in the shape of a section of a sphere or a circular cylinder of finite length, and for a family of pores or orifices with finite thickness. The results illustrate the distribution of shear stresses over the plane wall and inside the cavities or pores. It is found that in most cases, the distribution of shear stresses over the plane wall, around the depressions, is well approximated with that for flow over an orifice of infinitesimal thickness for which an exact solution is available. The kinematic structure of the flow is discussed with reference to eddy formation and three-dimensional flow reversal. It is shown that the thickness of a circular orifice or depth of a pore play an important role in determining the kinematical structure of the flow underneath the orifice in the lower half-space

Percutaneous Transluminal Angioplasty of Renal Artery Fibromuscular Dysplasia: Mid-term Results

International Nuclear Information System (INIS)

Kim, Hyo Jin; Do, Young Soo; Shin, Sung Wook; Park, Kwang Bo; Cho, Sung Ki; Choe, Yeon Hyeon; Choo, Sung Wook; Choo, In Wook; Kim, Duk Kyung

2008-01-01

To evaluate mid-term imaging, clinical follow-up, and restenosis rates from patients that had undergone percutaneous transluminal renal artery angioplasty (PTRA) for symptomatic renal artery fibromuscular dysplasia (FMD). Between March 1999 and July 2006, 16 consecutive renal artery FMD patients underwent PTRA for poorly controlled hypertension. The patients were enrolled into this retrospective study after receiving 19 primary and four secondary PTRAs in 19 renal artery segments. Follow-up monitoring of blood pressure, use of antihypertensive medication, and the serum creatinine level after PTRA were assessed at 1, 3, 6, 9, 12 months, and each following year. The degree of restenosis was evaluated with computed tomographic angiography (CTA) after PTRA at 6, 12 months, and every year if possible. Technical and clinical success rates for the treatment of FMD, and restenosis rates for the renal artery were evaluated. The technical success rate for primary PTRA was 79% (15/19) and the complication rate was 16% (3/19). Hypertension improved in 80% (12/15) of the patients after four weeks follow-up, and was finally cured or improved in 93% (14/15) during the mean follow-up period of 23.6 months. There was a cumulative 22% (4/18) restenosis rate during the follow-up period. All of the patients were treated with a second PTRA without complications and all of the patients were cured of hypertension after the second PTRA. Percutaneous transluminal renal artery angioplasty for clinically symptomatic renal FMD is technically and clinically successful and safe to perform. For all patients with restenosis, there was a good response after undergoing a second PTRA

Nuclear medical control of the efficiency of transluminal coronary angioplasty (TCA)

International Nuclear Information System (INIS)

Klepzig, H. Jr.; Scherer, D.; Kober, G.; Maul, F.D.; Kanemoto, N.; Standke, R.; Hoer, G.; Kaltenbach, M.; Frankfurt Univ.

1982-01-01

To assess the results of transluminal coronary angioplasty 48 patients with coronary heart disease were investigated at rest and during exercise with the ECG (46 patients), thallium-201 myocardial scintigraphy (26 patients), and equilibrium radionuclide ventriculography (38 patients). Exercise stress test was quantified by means of an ischemia score, myocardial scintigraphy by an vitality index and by corresponding redistribution factors, and radionuclide ventriculography by ejection fraction and maximum systolic volume change as a fraction of enddiastolic volume. This, the results show, that in selected cases, TCA can achieve improved left ventricular function and perfusion comparable to that of aortocoronary bypass surgery. (orig./MG) [de

Cardiac troponin T and CK-MB mass release after visually successful percutaneous transluminal coronary angioplasty in stable angina pectoris

DEFF Research Database (Denmark)

Ravkilde, J; Nissen, H; Mickley, H

1994-01-01

The incidence of cardiac troponin T (Tn-T) and creatine kinase (CK) isoenzyme MB mass release was studied in 23 patients with stable angina pectoris undergoing visually successful percutaneous transluminal coronary angioplasty (PTCA). Serial blood samples were drawn for measurement of serum Tn...

Impact of L/D on 90 Degree Sharp-Edge Orifice Flow with Manifold Passage Cross Flow (Preprint)

Science.gov (United States)

2007-04-30

that are observed by measurement as the flow transitions from non-cavitation to cavitation (turbulent flow), supercavitation , and finally separation in...include inception of cavitation, supercavitation , and separation. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...cavitation to cavitation (turbulent flow), supercavitation , and finally separation in sharp-edge 90 degree orifices. This study includes orifice L/D from

Laparoscopic right-sided colonic resection with transluminal colonoscopic specimen extraction

Science.gov (United States)

Kayaalp, Cuneyt; Kutluturk, Koray; Yagci, Mehmet Ali; Ates, Mustafa

2015-01-01

overall experience in the literature was 80% (12/15) in selected cases. CONCLUSION: Transcolonic specimen extraction for right-sided colonic resection is feasible in selected patients. Both natural orifice surgery and intracorporeal anastomosis avoids mini-laparotomy for specimen extraction or anastomosis. PMID:26380054

Cavitating Orifice: Flow regime transitions and low frequency sound production

NARCIS (Netherlands)

Testud, P.; Moussou, P.; Hirschberg, A.; Aurégan, Y.

2005-01-01

Detailed data are provided for the broadband noise in a cavitating pipe flow through a circular orifice in water. Experiments are performed under industrial conditions, i.e., with a pressure drop varying from 3 to 30 bars and a cavitation number in the range 0.10 = s = 0.77. The speed of sound

High Viscosity Liquid Flow through the Round Orifices at Small Reynold’s Numbe rs

Directory of Open Access Journals (Sweden)

V. N. Pil'gunov

2015-01-01

Full Text Available The paper presents research results of the mineral oil flow process with viscosity of 30 cSt through a round orifice with the sharp inlet edge of 0.9 mm in diameter. Pilot studies were conducted using a module from the transparent plexiglas that allowed to visualize hydrodynamic processes. The intake and off-take channels of the module with their sufficient extension had diameter of 20 mm (24 diameters of an orifice that allows us to consider compression of a stream as perfect. Drawing the enameled nichrome wire with a mark as a stripping isolation of 0.1 mm width enabled sounding of electric processes in the stream sections. Intensive high- frequency electric processes were revealed in cavitation stream. The paper gives experimental values of coefficientsof volumetric and mass flow at low (150 orifice. Free jet at a speed exceeding 50 m/s strikes a wall, barrier, installed at a distance of 100 diameters of the orifice: the reflection from walls, barriers shot blast, which caused intense foaming and conversion of oil into the two-phase mixture "fluid- combined air." We investigate the "life cycle" of a two-phase mixture: flotation bubbles in a viscous medium, and there was no air passes completely evolved in the dissolved state in a time not exceeding 30 minutes. Volumetric analysis of the foam allowed us to estimate the percentage of volumetric gas content of oil, which was 9% at 240С and atmospheric pressure of 97.5 kPa. An explanation of the possible cause cavitation edge at the end of a viscous fluid through an orifice with a sharp edge - appearance in fluid large tensile forces due to the centrifugal force on the particles of the fluid streams in passing peripheral sharp edge. Experimental research data flow of a viscous fluid in the annular orifice formed sharp edge and the surface of the string. Detected failure mode expiration free jet and conversion shareware transparent

[Effect of nattokinase on restenosis after percutaneous transluminal angioplasty of the abdominal artery in rabbits].

Science.gov (United States)

Gong, Min; Lin, Huan-bing; Wang, Qian; Xu, Jiang-ping

2008-08-01

To investigate the effect of nattokinase on intimal hyperplasia in rabbit abdominal artery after balloon injury and explore a novel strategy for the preventing restenosis after percutaneous transluminal angioplasty. Fifty-six New Zealand rabbits were randomly divided into 7 groups, namely the solvent control group, model group, natto extract lavage group, refined nattokinse lavage group, intravenous refined nattokinse injection group, clopidogrel group and clopidogrel-aspirin group. Balloon injury was induced by inserting the catheter through the femoral artery into the thoracic aorta of the rabbits. The platelet counts were notad and platelet aggregation was observed, and the abdominal artery was taken for pathological analysis. The expressions of MMP-2 and -9 in the abdominal artery were detected immunohistochemically. There was no significant difference in the platelet counts, platelet aggregation rate or MMP-2 and -9 expression between the model group and the nattokinse-treated groups (P>0.05). The stenosis index in each nattokinse-treated group was significantly greater and the neointimal proliferation index smaller than that of the model group (P<0.01 or 0.05). Nattokinse can inhibit restenosis of rabbit abdominal artery after percutaneous transluminal angioplasty, which is independent of its actions on the platelet or MMP-2 and -9 expressions.

Transgastric pure-NOTES peritoneoscopy and endoscopic ultrasonography for staging of gastrointestinal cancers

DEFF Research Database (Denmark)

Donatsky, Anders Meller; Vilmann, Peter; Meisner, Søren

2012-01-01

BACKGROUND: Human natural orifice transluminal endoscopic surgery (NOTES) has mainly been based on simultaneous laparoscopic assistance (hybrid NOTES), forgoing the theoretical benefits of the NOTES technique. This is due to a lack of NOTES-specific instruments and endoscopes, making pure-NOTES...... procedures difficult and time consuming. An area where pure NOTES could be adopted at its present stage of development is minimally invasive staging of gastrointestinal (GI) cancer. The aim of this study is to evaluate the feasibility of combining transgastric (TG) pure-NOTES peritoneoscopy...... and intraperitoneal endoscopic ultrasonography (ip-EUS) with intraluminal EUS (il-EUS) for peritoneal evaluation. METHODS: This was a feasibility and survival study where il-EUS followed by ip-EUS and peritoneoscopy was performed in 10 pigs subjected to TG pure NOTES. A score was given with regard to achieved...

A New Era of Minimally Invasive Surgery: Progress and Development of Major Technical Innovations in General Surgery Over the Last Decade.

Science.gov (United States)

Siddaiah-Subramanya, Manjunath; Tiang, Kor Woi; Nyandowe, Masimba

2017-10-01

Minimally invasive surgery (MIS) continues to play an important role in general surgery as an alternative to traditional open surgery as well as traditional laparoscopic techniques. Since the 1980s, technological advancement and innovation have seen surgical techniques in MIS rapidly grow as it is viewed as more desirable. MIS, which includes natural orifice transluminal endoscopic surgery (NOTES) and single-incision laparoscopic surgery (SILS), is less invasive and has better cosmetic results. The technological growth and adoption of NOTES and SILS by clinicians in the last decade has however not been uniform. We look at the differences in new developments and advancement in the different techniques in the last 10 years. We also aim to explain these differences as well as the implications in general surgery for the future.

Percutaneous transluminal angioplasty of an occluded surgical splenorenal shunt in a 4-year-old child after liver transplantation

Energy Technology Data Exchange (ETDEWEB)

Yussim, Ethan; Belenky, Alexander; Atar, Eli [Department of Diagnostic Radiology, Rabin Medical Center, Vascular and Interventional Radiology Unit, Petah Tikva (Israel); Shapiro, Rivka [Schneider Children' s Medical Center, Institute of Pediatric Gastroenterology and Nutrition, Petah Tikva (Israel); Mor, Eytan [Rabin Medical Center, Department of Organ Transplantation, Petah Tikva (Israel)

2005-07-01

Percutaneous transluminal angioplasty is increasingly used in children. We present a case of successful balloon angioplasty of an occluded surgical splenorenal shunt in a 4-year-old child who underwent liver transplantation because of biliary atresia. Percutaneous reopening of the shunt is a relatively safe procedure that may spare patients of surgical intervention. (orig.)

Percutaneous transluminal angioplasty of an occluded surgical splenorenal shunt in a 4-year-old child after liver transplantation

International Nuclear Information System (INIS)

Yussim, Ethan; Belenky, Alexander; Atar, Eli; Shapiro, Rivka; Mor, Eytan

2005-01-01

Percutaneous transluminal angioplasty is increasingly used in children. We present a case of successful balloon angioplasty of an occluded surgical splenorenal shunt in a 4-year-old child who underwent liver transplantation because of biliary atresia. Percutaneous reopening of the shunt is a relatively safe procedure that may spare patients of surgical intervention. (orig.)

Effect of Orifice Nozzle Design and Input Power on Two-Phase Flow and Mass Transfer Characteristics

Energy Technology Data Exchange (ETDEWEB)

Yang, Hei Cheon [Chonnam Nat’l Univ., Gwangju (Korea, Republic of)

2016-04-15

It is necessary to investigate the input power as well as the mass transfer characteristics of the aeration process in order to improve the energy efficiency of an aerobic water treatment. The objective of this study is to experimentally investigate the effect of orifice nozzle design and input power on the flow and mass transfer characteristics of a vertical two-phase flow. The mass ratio, input power, volumetric mass transfer coefficient, and mass transfer efficiency were calculated using the measured data. It was found that as the input power increases the volumetric mass transfer coefficient increases, while the mass ratio and mass transfer efficiency decrease. The mass ratio, volumetric mass transfer coefficient, and mass transfer efficiency were higher for the orifice configuration with a smaller orifice nozzle area ratio. An empirical correlation was proposed to estimate the effect of mass ratio, input power, and Froude number on the volumetric mass transfer coefficient.

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.

Transluminal recanalization of chronic total occlusion of radial artery using rendezvous technique: a case report and literature review.

Science.gov (United States)

Arabi, Mohammad; Ahmed, Ishtiaq; Qattan, Nabeel

2014-01-01

Although endovascular management of lower extremity peripheral arterial disease (PAD) is well studied, little information exists regarding endovascular treatment of critical upper limb ischemia. We report a case of transluminal recanalization of right radial artery chronic total occlusion (CTO) using rendezvous technique in a patient with critical hand ischemia and dry gangrene of the right index finger.

Laboratory evaluation of a vibrating orifice monodisperse aerosol generator

International Nuclear Information System (INIS)

Everitt, N.M.; Snelling, K.W.

1985-02-01

The Berglund-Liu vibrating orifice aerosol generator is capable of producing monodisperse particles in the diameter range 5 to 50 μm. Experiments have been carried out to set up and evaluate such a generator for the preparation of standard liquid (olive oil) and solid (methylene blue) aerosols in the size range 8 to 13 μm. Modifications have been made to the apparatus to improve its performance and increase its particle output. (author)

[The usefullness of percutaneous transluminal balloon angioplasty in the management of budd-Chiari syndrome].

Science.gov (United States)

Kim, Se Hwan; Yu, Kyung Sool; Baek, Seung Min; Lee, Seung Yup; Kim, Hyun Su; Tak, Won Young; Kweon, Young Oh; Kim, Sung Kook; Choi, Yong Hwan; Chung, Joon Mo

2002-06-01

Membranous obstruction is the most common cause of Budd-Chiari syndrome in Orientals. Recently, percutaneous transluminal balloon angioplasty (PTBA) has been successfully applied as a treatment of membranous obstruction. We evaluated etiologies and clinical manifestations in our cases and the usefulness of PTBA. Twelve cases of Budd-Chiari syndrome were analyzed. 50.3 years was the average age of the cases (ranging from 37 to 67 years). Major symptoms or signs were superficial collateral vessels on the chest or the abdomen in 6 cases, ascites in 3, abdominal pain in 4, hepatomegaly in 4, splenomegaly in 3, melena or hematemesis in 2, and leg edema in 2. Upper gastrointestinal endoscopy showed esophageal varices in 6 cases and two of these 6 cases had gastric varices. Of 8 cases with liver cirrhosis, 4 were classified as Child-Pugh class A and 4 as B. Four patients with cirrhosis had concurrent hepatocellular carcinoma including 1 patient who was HBs Ag positive. Etiologies were membranous obstruction in 11 cases and protein C deficiency in 1 case. The main site of obstruction was IVC in 8 and hepatic vein in 4. PTBA was successfully performed in 8 cases of membranous obstruction. During the mean follow-up period of 27.6 months (12-40 months), there were no reobstructions except in 2 cases. The most common cause of Budd-Chiari syndrome in our cases was membranous obstruction of IVC. Percutaneous transluminal balloon angioplasty is a very useful treatment method.

Preoperative ultrasound measurements predict the feasibility of gallbladder extraction during transgastric natural orifice translumenal endoscopic surgery cholecystectomy.

Science.gov (United States)

Santos, Byron F; Auyang, Edward D; Hungness, Eric S; Desai, Kush R; Chan, Edward S; van Beek, Darren B; Wang, Edward C; Soper, Nathaniel J

2011-04-01

Extraction of a gallbladder through an endoscopic overtube during natural orifice translumenal endoscopic surgery (NOTES) transgastric cholecystectomy avoids potential injury to the esophagus. This study examined the rate of successful gallbladder specimen extraction through an overtube and hypothesized that preoperative ultrasound findings could predict successful specimen passage. Gallbladder specimens from patients undergoing laparoscopic cholecystectomy were measured, and an attempt was made to pull the specimens through a commercially available overtube with an inner diameter of 16.7-mm. A radiologist blinded to the outcomes reviewed the available preoperative ultrasound measurements from these patients. Ultrasound dimensions including gallbladder length, width, and depth; wall thickness; common bile duct diameter; and size of the largest gallstone (LGS) were recorded. Multiple logistic regression analysis was performed to determine whether ultrasound findings and patient characteristics (age, body mass index [BMI], and sex) could predict the ability of a specimen to pass through the overtube. Of 57 patients, 44 (77%) who had preoperative ultrasounds available for electronic review were included in the final analysis. Gallstones were present in 35 (79%) of these 44 patients. Intraoperative gallbladder perforation occurred in 18 (41%) of the 44 patients, and 16 (36%) of the 44 gallbladders could be extracted through the overtube. Measurement of LGS was possible for 23 patients, and indeterminate gallstone size (IGS) was determined for 12 patients. The rate for passage of perforated versus intact gallbladders was similar (40% vs. 23%; p = 0.054). The LGS (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.02-1.33; p = 0.021) and IGS (OR, 22.97; 95% CI, 1.99-265.63; p = 0.025) predicted failed passage on multivariate logistic regression analysis. The passage rate was 80% for LGS smaller than 10 mm or no stones present, 18% for LGS 10 mm or larger, and 8% for

Repair of Double Orifice Left AV Valve (DOLAVV with Endocardial Cushion Defect in Adult

Directory of Open Access Journals (Sweden)

Vivek Velayudhan Pillai

Full Text Available Abstract Double orifice left atrioventricular valve (DOLAVV or double orifice mitral valve (DOMV is a rare congenital cardiac anomaly manifesting either as an isolated lesion (mitral stenosis or mitral insufficiency or in association with other congenital cardiac defects. Signs of mitral valve disease are usually present along with the symptoms of associated coexistent congenital heart diseases. Mitral insufficiency due to annular dilatation is seen when DOLAVV is associated with endocardial cushion defects. Surgical intervention like mitral valve repair or replacement is required in 50% of patients and yields good results. We report a case of a 56-year-old lady who successfully underwent surgical correction of DOLAVV with partial atrioventricular canal defect.

Complications in percutaneous transluminal stenting for carotid artery stenosis

International Nuclear Information System (INIS)

Li Shenmao; Miao Zhongrong; Zhu Fengshui; Ji Xunming; Jiao Liqun; Qi Jianshu; Ling Feng

2007-01-01

Objective: To discuss the complications of endovascular stenting for carotid artery stenosis. Methods: Cerebral vascular angiography and cervical Doppler sonography were performed in 648 patients with carotid artery stenosis. Emboli-protected device was used in 365 patients and none in 283 patients. Results: All 648 patients were technically successful (100%). Symptoms disappeared or improved in 78.7% patients. Slow heart rate during operation existed in 26.4% patients. Embolism caused by dislodgment of emboli occurred in 5 patients, 3 of them recovered after treatment and 2 had unilateral dyskinesias. Intracranial hemorrhage occurred in 3 patients. Stroke or death within 30 days after operation occurred in 6 patients(1.24%). 322 patients (77.8%)were followed up. Restenosis occurred in 17 patients(3.3%). Conclusion: Percutaneous transluminal stenting is a safe option for carotid artery stenosis. Correct evaluation of clinical and angiographic data before operation, together with normative manipulation and nursing during and after operation are the key points to avoid complications. (authors)

Transluminal Recanalization of Chronic Total Occlusion of Radial Artery Using Rendezvous Technique: A Case Report and Literature Review

Directory of Open Access Journals (Sweden)

Mohammad Arabi

2014-01-01

Full Text Available Although endovascular management of lower extremity peripheral arterial disease (PAD is well studied, little information exists regarding endovascular treatment of critical upper limb ischemia. We report a case of transluminal recanalization of right radial artery chronic total occlusion (CTO using rendezvous technique in a patient with critical hand ischemia and dry gangrene of the right index finger.

Long-Term Follow-up of the PADI Trial : Percutaneous Transluminal Angioplasty Versus Drug-Eluting Stents for Infrapopliteal Lesions in Critical Limb Ischemia

NARCIS (Netherlands)

Spreen, Marlon I; Martens, Jasper M; Knippenberg, Bob; van Dijk, Lukas C; De Vries, Jean-Paul P. M.; Vos, Jan Albert; de Borst, Gert Jan; Vonken, Evert-Jan P A; Bijlstra, Okker D; Wever, Jan J; Statius van Eps, Randolph G; Mali, Willem P Th M; van Overhagen, Hendrik

2017-01-01

BACKGROUND: Clinical outcomes reported after treatment of infrapopliteal lesions with drug-eluting stents (DESs) have been more favorable compared with percutaneous transluminal angioplasty with a bailout bare metal stent (PTA-BMS) through midterm follow-up in patients with critical limb ischemia.

The exposure of radiologists and patients to radiation during coronary angiography and percutaneous transluminal coronary angioplasty (PTCA)

International Nuclear Information System (INIS)

Karppinen, J.; Parviainen, T.

1993-03-01

The exposure of radiologists and patients to radiation during coronary angiography and percutaneous transluminal coronary angioplasty (PTCA) in Finland was studied using phantom measurements. Additional tests were made concerning the performance of TV fluoroscopy systems, cine fluorographic units and film processing. These tests include sensitometric quality control of film processing, automatic exposure control in fluoroscopy and cinefluorography, and contrast and resolution in a cine frame and TV image

Appendiceal Abscesses Reduced in Size by Drainage of Pus from the Appendiceal Orifice during Colonoscopy: A Report of Three Cases

Directory of Open Access Journals (Sweden)

Shinjiro Kobayashi

2014-11-01

Full Text Available Interval appendectomy (IA for appendiceal abscesses is useful for avoiding extended surgery and preventing postoperative complications. However, IA has problems in that it takes time before an abscess is reduced in size in some cases and in that elective surgery may result in a delay in treatment in patients with a malignant tumor of the appendix. In order to rule out malignancy, we performed colonoscopy on three patients with an appendiceal abscess that did not decrease in size 5 or more days after IA. After malignancy had been ruled out by examination of the area of the appendiceal orifice, the appendiceal orifice was compressed with a colonoscope, and a catheter was inserted through the orifice. Then, drainage of pus was observed from the appendiceal orifice into the cecal lumen. Computed tomography performed 3 days after colonoscopy revealed a marked reduction in abscess size in all patients. No endoscopy-related complication was noted. Colonoscopy in patients with an appendiceal abscess may not only differentiate malignant tumors, but also accelerate reduction in abscess size.

Flow through a cylindrical pipe with a periodic array of fractal orifices

NARCIS (Netherlands)

van Melick, P.A.J.; Geurts, Bernardus J.

2013-01-01

We apply direct numerical simulation (DNS) of the incompressible Navier–Stokes equations to predict flow through a cylindrical pipe in which a periodic array of orifice plates with a fractal perimeter is mounted. The flow is simulated using a volume penalization immersed boundary method with which

Flow through a cylindrical pipe with a periodic array of fractal orifices

NARCIS (Netherlands)

van Melick, P.A.J.; Geurts, B.J.

2013-01-01

We apply direct numerical simulation (DNS) of the incompressible Navier-Stokes equations to predict flow through a cylindrical pipe in which a periodic array of orifice plates with a fractal perimeter is mounted. The flow is simulated using a volume penalization immersed boundary method with which

MR imaging of the entry, the abdominal communicating orifice, and the retrograde dissection in aortic dissections

International Nuclear Information System (INIS)

Yoshida, Y.; Mukohara, N.; Nakamura, K.; Sugimura, K.; Kono, M.

1986-01-01

MR imaging (1.5 T) was performed on 41 patients with aortic dissection. Entries were clearly visualized on the MR images as partial defects of the intimal flap in 18 of 21 patients (85.7%). In eight of ten patients, the locations of abdominal communicating orifices corresponded to the lowest signal intensities of the false lumina. Retrograde disections were diagnosed in all six patients from gradual increases in signal intensities of the false lumina toward the heart. MR imaging was very useful in diagnosing entries of the thoracic aorta, abdominal communicating orifices between true and false lumina, and retrograde dissections

Comparison of the effect of stem cell therapy and percutaneous transluminal angioplasty on diabetic foot disease in patients with critical limb ischemia

Czech Academy of Sciences Publication Activity Database

Dubský, M.; Jirkovská, A.; Bém, R.; Fejfarová, V.; Pagacová, L.; Němcová, A.; Sixta, B.; Chlupáč, J.; Peregrin, J. H.; Syková, Eva; Jude, E. B.

2014-01-01

Roč. 16, č. 12 (2014), s. 1733-1738 ISSN 1465-3249 Grant - others:GA MZd(CZ) 00023001IKEM Institutional support: RVO:68378041 Keywords : critical limb ischemia * stem cell therapy * percutaneous transluminal angioplasty Subject RIV: FH - Neurology Impact factor: 3.293, year: 2014

Coronal microleakage of three different dental biomaterials as intra-orifice barrier during nonvital bleaching

Directory of Open Access Journals (Sweden)

Nafiseh Zarenejad

2015-01-01

Full Text Available Background: This study was designed to assess the microleakage of glass-ionomer (GI, mineral trioxide aggregate (MTA, and calcium-enriched mixture (CEM cement as coronal orifice barrier during walking bleaching. Materials and Methods: In this experimental study, endodontic treatment was done for 70 extracted human incisors without canal calcification, caries, restoration, resorption, or cracks. The teeth were then divided into three experimental using "Simple randomization allocation" (n = 20 and two control groups (n = 5. The three cements were applied as 3-mm intra-orifice barrier in test groups, and bleaching process was then conducted using a mixture of sodium perborate powder and distilled water, for 9 days. For leakage evaluation, bovine serum albumin marker was traced in a dual-chamber technique with Bradford indicator. The Kruskal-Wallis and Mann-Whitney tests were used for statistical analysis. Results: The mean ± standard deviation leakage of samples from negative control, positive control, GI, MTA, and CEM cement groups were 0.0, 8.9 ± 0.03, 0.47 ± 0.02, 0.48 ± 0.02, and 0.49 ± 0.02 mg/mL, respectively. Statistical analysis showed no significant difference between three experimental groups (P > 0.05. Conclusion: It is concluded that GI, MTA, and CEM cements are considered as suitable intra-orifice barrier to provide coronal seal during walking bleaching.

Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber

Energy Technology Data Exchange (ETDEWEB)

Guerra, V.G.; Goncalves, J.A.S. [Department of Chemical Engineering, Federal University of Sao Carlos, Via Washington Luiz, Km. 235, 13565-905 Sao Carlos, SP (Brazil); Coury, J.R. [Department of Chemical Engineering, Federal University of Sao Carlos, Via Washington Luiz, Km. 235, 13565-905 Sao Carlos, SP (Brazil)], E-mail: jcoury@ufscar.br

2009-01-15

Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets.

Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber

International Nuclear Information System (INIS)

Guerra, V.G.; Goncalves, J.A.S.; Coury, J.R.

2009-01-01

Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets

Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber.

Science.gov (United States)

Guerra, V G; Gonçalves, J A S; Coury, J R

2009-01-15

Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets.

Transluminal radio-frequency thermal ablation using a stent-type electrode: an experimental study

Energy Technology Data Exchange (ETDEWEB)

Kim, Young Sun; Rhim, Hyun Chul [Hanyang University College of Medicine, Seoul (Korea, Republic of); Song, Ho Young [Asan Medical Center, Seoul (Korea, Republic of)] [and others

2003-06-01

To assess the feasibility of transluminal radiofrequency thermal ablation using a stent-type electrode and to determine, by means of in-vivo and in-vivo animal studies, the appropriate parameters. In-vivo: the radiofrequency electrode used was a self-expandable nitinol stent with 1cm insulated ends. A stent was placed in the portal vein of bovine liver, and ablations at target temperatures of 70, 80, 90, and 100 .deg. C were performed. Ablated sizes were measured longitudinally. In vivo: four mongrel dogs were anesthetized, and a stent was inserted in the common bile duct under fluoroscopic guidance through an ultrasound-guided gall bladder puncture site. The ablation temperature was set at 80 .deg. C, and each dog underwent proximal and distal esophageal ablations lasting 12 minutes. They were sacrificed immediately. In-vivo: ablated sizes showed significant correlation with target temperatures (r>0.04; p<0.05). Although most lesions were fusiform, dumbbell-shaped lesions with central thinning were found in two cases in the 70 .deg. C group. In all cases in the 70 .deg. C and 80 .deg. C group, the length of the insulated segment was less than 1cm. In-vivo: at microscopy, tissues at the center of the biliary stent showed more prominent pathological change than those at the periphery while those remote from the stent showed minimal or no change. In esophageal ablations, the mean highest temperature was 48.6 .deg. C. Microscopy demonstrated the destruction and shedding of mucosa, edema, and coagulation necrosis of submucosa, but in muscle layers no abnormalities were apparent. Transluminal radio-frequency thermal ablation using a stent-type electrode may be useful for elongating patency. The appropriate target temperature for biliary ablation is 80 .deg. C.

Is the Watanabe heritable hyperlipidemic rabbit a suitable experimental model for percutaneous transluminal coronary angioplasty in humans? A light microscopic, immunohistochemical and ultrastructural study

NARCIS (Netherlands)

Wanibuchi, H.; Dingemans, K. P.; Becker, A. E.; Ueda, M.; Naruko, T.; Tanizawa, S.; Nakamura, K.

1993-01-01

This study was designed to assess an experimental model for the study of mechanisms that underlie restenosis after percutaneous transluminal coronary angioplasty. The Watanabe heritable hyperlipidemic (WHHL) rabbit lacks the receptor for low density lipoproteins, produces atherosclerotic lesions

Flow motion waves with high and low frequency in severe ischaemia before and after percutaneous transluminal angioplasty

OpenAIRE

Hoffmann, Ulrich; Schneider, Ernst; Bollinger, Alfred

2017-01-01

Study of objective - The aim was to evaluate skin flux and prevalence of low and high frequency flow motion waves in patients with severe ischaemia due to peripheral arterial occlusive disease before and after percutaneous transluminal angioplasty (PTA) with and without local thrombolysis. Design - Flow motion was recorded by the laser Doppler technique at the dorsum of the foot before, one day, and one month after PTA. The results were separately analysed in patients with successful and unsu...

Burnout experiments in freon 12 using different types of orifices to simulate the core grids

International Nuclear Information System (INIS)

Ladeira, L.; Katsaounis, A.; Orlowski, R.; Fulfs, H.; Hofmann, K.

1978-01-01

This paper will report on burnout experiments carried out in freon 12 mainly at steady state and further at mass flow or power transient conditions with annular test sections axially uniformly heating either the inside or both the inside and outside rod. The runs are performed without orifice and using three different types of orifices simulating the reactor spacer grid. An important influence of the flow restriction on burnout position and value is measured. Furthermore, the comparison between the burnout correlations W2, W3, B and W2 and GE and experimental results from the literature using simple test section geometries in water and freon 12 demonstrate, that the accuracy is more or less comparable for both fluids. (orig.) [de

A computational investigation on the influence of the use of elliptical orifices on the inner nozzle flow and cavitation development in diesel injector nozzles

International Nuclear Information System (INIS)

Molina, S.; Salvador, F.J.; Carreres, M.; Jaramillo, D.

2014-01-01

Highlights: • The influence of elliptical orifices on the inner nozzle flow is compared. • Five nozzles with different elliptical and circular orifices are simulated. • Differences in the flow coefficients and cavitation morphology are observed. • Horizontal axis orifices are ease to cavitate, with a higher discharge coefficient. • A better mixing process quality is expected for the horizontal major axis nozzles. - Abstract: In this paper a computational study was carried out in order to investigate the influence of the use of elliptical orifices on the inner nozzle flow and cavitation development. With this aim, a large number of injection conditions have been simulated and analysed for 5 different nozzles: four nozzles with different elliptical orifices and one standard nozzle with circular orifices. The four elliptical nozzles differ from each other in the orientation of the major axis (vertical or horizontal) and in the eccentricity value, but keeping the same outlet section in all cases. The comparison has been made in terms of mass flow, momentum flux and other important non-dimensional parameters which help to describe the behaviour of the inner nozzle flow: discharge coefficient (C d ), area coefficient (C a ) and velocity coefficient (C v ). The simulations have been done with a code able to simulate the flow under either cavitating or non-cavitating conditions. This code has been previously validated using experimental measurements over the standard nozzle with circular orifices. The main results of the investigation have shown how the different geometries modify the critical cavitation conditions as well as the discharge coefficient and the effective velocity. In particular, elliptical geometries with vertically oriented major axis are less prone to cavitate and have a lower discharge coefficient, whereas elliptical geometries with horizontally oriented major axis are more prone to cavitate and show a higher discharge coefficient

Simulation of Micro-Channel and Micro-Orifice Flow Using Lattice Boltzmann Method with Langmuir Slip Model

Directory of Open Access Journals (Sweden)

A. R. Rahmati

2016-12-01

Full Text Available Because of its kinetic nature and computational advantages, the Lattice Boltzmann method (LBM has been well accepted as a useful tool to simulate micro-scale flows. The slip boundary model plays a crucial role in the accuracy of solutions for micro-channel flow simulations. The most used slip boundary condition is the Maxwell slip model. The results of Maxwell slip model are affected by the accommodation coefficient significantly, but there is not an explicitly relationship between properties at wall and accommodation coefficient. In the present wok, Langmuir slip model is used beside LBM to simulate micro-channel and micro-orifice flows. Slip velocity and nonlinear pressure drop profiles are presented as two major effects in such flows. The results are in good agreement with existing results in the literature.

Evaluation of the flow-accelerated corrosion downstream of an orifice. 2. Measurement of corrosion rate and evaluation on the effects of the flow field

International Nuclear Information System (INIS)

Nagaya, Yukinori; Utanohara, Yoichi; Nakamura, Akira; Murase, Michio

2008-01-01

In this study, in order to evaluate the effects of flow field on corrosion rate due to flow accelerated corrosion (FAC), a corrosion rate downstream of an orifice was measured using the electric resistance method. The diameter of the pipe is 50 mm and that of the orifice is 24.3 mm, and flow velocity of the experimental loop was set at 5m/s, and the temperature of water was controlled within ±1 at 150deg-C. There were no significant circumferential difference in measured corrosion rate, and the maximum corrosion rate was observed at 1D or 2D downstream from the orifice. The ratios of the measured corrosion rate and the calculated wall shear stress at the 1D downstream from the orifice to the value at upstream under well developed flow agreed well. (author)

Advanced ultrasonic technology for natural gas measurement

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-11-15

In recent years, due to rising environmental and safety concerns, increasing commodity prices, and operational inefficiencies, a paradigm shift has been taking place with respect to gas measurement. The price of natural gas depends on the location, time of the year, and type of consumer. There is wide uncertainty associated with an orifice meter. This paper presents the use of advanced ultrasonic technology for the measurement of natural gas. For many years, multi-path ultrasonic meters with intelligent sensor technology have been used for gas measurement. This paper gives the various applications of ultrasonic technology along with their advantages and a draws a comparison with orifice meters. From the study it can be concluded that extensive advances in the use of ultrasonic technology for gas measurement have widened the areas of application and that varying frequencies combined with sealed transducer designs make it possible to measure atmospheric and sour gas in custody transfer process control and flaring accurately.

Successful intestinal ischemia treatment by percutaneus transluminal angioplasty of visceral arteries in a patient with abdominal angina

Directory of Open Access Journals (Sweden)

Nenezić Dragoslav

2011-01-01

Full Text Available Introduction. Abdominal angina, also known as chronic mesenteric ischemia or intestinal angina, is a rare disease caused by intestinal flow reduction due to stenosis or occlusion of mesenteric arteries. A case of successful treatment of a patient with abdominal angina by percutaneous transuliminal angioplasty of high-grade superior mesenteric artery and coeliac trunk stenosis was presented. Case Outline. A 77-year-old male patient was admitted at our Clinic for severe postprandial abdominal pains followed by frequent diarrhoeas. Extensive gastrointestinal investigations were performed and all results were normal. Multislice computerized (MSCT arteriography was indicated which revealed ostial celiac trunk and superior mesenteric artery subocclusion. Percutaneous transluminal angioplasty of the superior mesenteric artery and coeliac trunk was done with two stents implantation. Just a few hours following the intervention, after food ingestion, there were no abdominal pains. Six months later, the patient described a significant feeling of relief after food ingestion and no arduousness at all. Conclusion. High-grade visceral arteries stenoses in patients with intestinal ischemia symptoms can be treated by either surgical procedures or percutaneus transluminal angioplasty. In cases when a low operative risk is anticipated, surgical treatment is recommended due to a better anatomical outcome, while percutaneus angioplasty is advised to elderly patients in whom increased operative risks can be expected.

Simplified one-orifice venoplasty for middle hepatic vein reconstruction in adult living donor liver transplantation using right lobe grafts.

Science.gov (United States)

Kim, Joo Dong; Choi, Dong Lak; Han, Young Seok

2014-05-01

Middle hepatic vein (MHV) reconstruction is often essential to avoid hepatic congestion and serious graft dysfunction in living donor liver transplantation (LDLT). The aim of this report was to introduce evolution of our MHV reconstruction technique and excellent outcomes of simplified one-orifice venoplasty. We compared clinical outcomes with two reconstruction techniques through retrospective review of 95 recipients who underwent LDLT using right lobe grafts at our institution from January 2008 to April 2012; group 1 received separate outflow reconstruction and group 2 received new one-orifice technique. The early patency rates of MHV in group 2 were higher than those in group 1; 98.4% vs. 88.2% on postoperative day 7 (p = 0.054) and 96.7% vs. 82.4% on postoperative day 14, respectively (p = 0.023). Right hepatic vein (RHV) stenosis developed in three cases in group 1, but no RHV stenosis developed because we adopted one-orifice technique (p = 0.043). The levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in group 2 were significantly lower than those in group 1 during the early post-transplant period. In conclusion, our simplified one-orifice venoplasty technique could secure venous outflow and improve graft function during right lobe LDLT. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[Urethroplasty with transection of urethral orifice and preservation and lengthening of urethral plate: highly applicable to the treatment of hypospadias].

Science.gov (United States)

Wang, Wen-Min; Qiu, Wei-Feng; Qian, Chong

2010-07-01

To explore the feasibility of urethroplasty with transection of the urethral orifice and preservation and lengthening of the urethral plate in the treatment of hypospadias. Forty-eight patients with hypospadias (18 of the coronal type, 21 the penile type, 8 the penoscrotal type and 1 the perineal type) underwent urethroplasty with transection of the urethral orifice and preservation and lengthening of the urethral plate. The surgical effects were observed by following up the patients for 3-27 months. One-stage surgical success was achieved in 44 of the cases, with satisfactory functional and cosmetic results but no complications. Two cases developed urinary fistula and another 2 urethral stricture, but all cured by the second surgery. Urethroplasty with transection of the urethral orifice and preservation and lengthening of the urethral plate is a simple, safe and effective surgical procedure for the treatment of hypospadias.

Flow resistance of orifices and spacers of BWR thermal-hydraulic and neutronic coupling loop

International Nuclear Information System (INIS)

Iguchi, Tadashi; Asaka, Hideaki; Nakamura, Hideo

2002-03-01

Authors are performing THYNC experiments to study thermal-hydraulic instability under neutronic and thermal-hydraulic coupling. In THYNC experiments, the orifices are installed at the exit of the test section and the spacers are installed in the test section, in order to properly simulate in-core thermal-hydraulics in the reactor core. It is necessary to know the flow resistance of the orifices and spacers for the analysis of THYNC experimental results. Consequently, authors measured the flow resistance of orifice and spacer under single-phase and two-phase flows. Using the experimental results, authors investigated the dependency of the flow resistances on the parameters, such as pressure, mass flux, an geometries. Furthermore, authors investigated the applicability of the basic two-phase flow models, for example the separate flow model, to the two-phase flow multiplier. As the result of the investigation on the single-phase flow experiment, it was found (1) that the effects of pressure and mass flux flow resistance are described by a function of Reynolds number, and (2) that flow resistances of the orifice and the spacer are calculated with the previous prediction methods. However, it was necessary to introduce an empirical coefficient, since it was difficult to predict accurately the flow resistance only with the previous prediction method due to the complicated geometry dependency, for example a flow area blockage ratio. On the other hand, according to the investigation on two-phase flow experiment, the followings were found. (1) Relation between the two-phase flow multiplier and the quality is regarded to be linear under pressure of 2MPa - 7MPa. The relation is dependent on pressure and geometry, and is little dependent on mass flux. (2) Relation between the two-phase flow multiplier and void fraction is little dependent on pressure, mass flux, and geometry under pressure of 0.2MPa - 7MPa and void fraction less than 0.6. The relation is less dependent on

Behandling af renovaskulær hypertension med transluminal angioplastik--13 års erfaring--sekundærpublikation

DEFF Research Database (Denmark)

Øvrehus, Kristian Altern; Andersen, Poul Erik; Jacobsen, Ib Abildgaard

2008-01-01

angioplasty. A total of 124 patients were treated; 31% were normotensive immediately after angioplasty, 59% had improved blood pressure control and 10% had unchanged hypertension. The corresponding figures after six months and at the latest follow-up were 13, 72 and 15%. Udgivelsesdato: 2008-Jan-21......The result of treatment of renovascular hypertension by renal angioplasty over a period of 13 years was analysed. Patients with a positive diagnostic work-up with renography or renal vein renin measurement had renal angiography performed and in cases of renal artery stenosis, transluminal...

Wall-resolved Large Eddy Simulation of a flow through a square-edged orifice in a round pipe at Re = 25,000

Energy Technology Data Exchange (ETDEWEB)

Benhamadouche, S., E-mail: sofiane.benhamadouche@edf.fr; Arenas, M.; Malouf, W.J.

2017-02-15

Highlights: • Wall-resolved LES can predict the flow through a square-edged orifice at Re = 25,000. • LES results are compared with the available experimental data and ISO 5167-2. • Pressure loss and discharge coefficients are in very good agreement with ISO 5167-2. • The present wall-resolved LES could be used as reference data for RANS validation. - Abstract: The orifice plate is a pressure differential device frequently used for flow measurements in pipes across different industries. The present study demonstrates the accuracy obtainable using a wall-resolved Large Eddy Simulation (LES) approach to predict the velocity, the Reynolds stresses, the pressure loss and the discharge coefficient for a flow through a square-edged orifice in a round pipe at a Reynolds number of 25,000. The ratio of the orifice diameter to the pipe diameter is β = 0.62, and the ratio of the orifice thickness to the pipe diameter is 0.11. The mesh is sized using refinement criteria at the wall and preliminary RANS results to ensure that the solution is resolved beyond an estimated Taylor micro-scale. The inlet condition is simulated using a recycling method, and the LES is run with a dynamic Smagorinsky sub-grid scale (SGS) model. The sensitivity to the SGS model and to the pressure–velocity coupling is shown to be small in the present study. The LES is compared with the available experimental data and ISO 5167-2. In general, the LES shows good agreement with the velocity from the experimental data. The profiles of the Reynolds stresses are similar, but an offset is observed in the diagonal stresses. The pressure loss and discharge coefficients are shown to be in very good agreement with the predictions of ISO 5167-2. Therefore, the wall-resolved LES is shown to be highly accurate in simulating the flow across a square-edged orifice.

Wall-resolved Large Eddy Simulation of a flow through a square-edged orifice in a round pipe at Re = 25,000

International Nuclear Information System (INIS)

Benhamadouche, S.; Arenas, M.; Malouf, W.J.

2017-01-01

Highlights: • Wall-resolved LES can predict the flow through a square-edged orifice at Re = 25,000. • LES results are compared with the available experimental data and ISO 5167-2. • Pressure loss and discharge coefficients are in very good agreement with ISO 5167-2. • The present wall-resolved LES could be used as reference data for RANS validation. - Abstract: The orifice plate is a pressure differential device frequently used for flow measurements in pipes across different industries. The present study demonstrates the accuracy obtainable using a wall-resolved Large Eddy Simulation (LES) approach to predict the velocity, the Reynolds stresses, the pressure loss and the discharge coefficient for a flow through a square-edged orifice in a round pipe at a Reynolds number of 25,000. The ratio of the orifice diameter to the pipe diameter is β = 0.62, and the ratio of the orifice thickness to the pipe diameter is 0.11. The mesh is sized using refinement criteria at the wall and preliminary RANS results to ensure that the solution is resolved beyond an estimated Taylor micro-scale. The inlet condition is simulated using a recycling method, and the LES is run with a dynamic Smagorinsky sub-grid scale (SGS) model. The sensitivity to the SGS model and to the pressure–velocity coupling is shown to be small in the present study. The LES is compared with the available experimental data and ISO 5167-2. In general, the LES shows good agreement with the velocity from the experimental data. The profiles of the Reynolds stresses are similar, but an offset is observed in the diagonal stresses. The pressure loss and discharge coefficients are shown to be in very good agreement with the predictions of ISO 5167-2. Therefore, the wall-resolved LES is shown to be highly accurate in simulating the flow across a square-edged orifice.

Percutaneous transluminal angioplasty of renal artery: therapeutic experience of 31 patients

International Nuclear Information System (INIS)

Kim, Seung Cheol; Park, Jae Hyung; Chung, Jin Wook; Han, Joon Koo; Kim, Hong Dae; Jeong, Yoong Ki; Kim, Seung Hoon; Yeon, Kyung Mo

1995-01-01

The purpose of this study is to introduce the experience of 31 patients who had renovascular hypertension and underwent percutaneous transluminal angioplasty of renal artery (PTA). The subjects were 31 patients with hypertension and stenotic renal artery or arteries on angiography. The criteria of stenosis is more than 50% narrowing of the artery. The technical results were considered to be successful if residual stenosis is less than 50%. The clinical results were classified as cure, improvement and fail. And clinical results were analyzed according to the follow-up duration, short term (≤6 mo) and long term (> 6 mo). Technical success rate was 90.2% (37/41) and clinical success rate were 82.8% (24/29) on short term follow-up and 84.2% (16/19) on long term follow-up. Recurred cases were 7 cases. PTA is a safe and effective therapeutic modality on renovascular hypertension

Peroral Endoscopic Myotomy for Treating Achalasia and Esophageal Motility Disorders

Science.gov (United States)

Youn, Young Hoon; Minami, Hitomi; Chiu, Philip Wai Yan; Park, Hyojin

2016-01-01

Peroral endoscopic myotomy (POEM) is the application of esophageal myotomy to the concept of natural orifice transluminal surgery (NOTES) by utilizing a submucosal tunneling method. Since the first case of POEM was performed for treating achalasia in Japan in 2008, this procedure is being more widely used by many skillful endosopists all over the world. Currently, POEM is a spotlighted, emerging treatment option for achalasia, and the indications for POEM are expanding to include long-standing, sigmoid shaped esophagus in achalasia, even previously failed endoscopic treatment or surgical myotomy, and other spastic esophageal motility disorders. Accumulating data about POEM demonstrate excellent short-term outcomes with minimal risk of major adverse events, and some existing long-term data show the efficacy of POEM to be long lasting. In this review article, we review the technical details and clinical outcomes of POEM, and discuss some considerations of POEM in special situations. PMID:26717928

Effects of Burner Configurations on the Natural Oscillation Characteristics of Laminar Jet Diffusion Flames

Directory of Open Access Journals (Sweden)

K. R. V. Manikantachari

2015-09-01

Full Text Available In this work, effects of burner configurations on the natural oscillations of methane laminar diffusion flames under atmospheric pressure and normal gravity conditions have been studied experimentally. Three regimes of laminar diffusion flames, namely, steady, intermittent flickering and continuous flickering have been investigated. Burner configurations such as straight pipe, contoured nozzle and that having an orifice plate at the exit have been considered. All burners have the same area of cross section at the exit and same burner lip thickness. Flame height data has been extracted from direct flame video using MATLAB. Shadowgraph videos have been captured to analyze the plume width characteristics. Results show that, the oscillation characteristics of the orifice burner is significantly different from the other two burners; orifice burner produces a shorter flame and wider thermal plume width in the steady flame regime and the onset of the oscillation/flickering regimes for the orifice burner occurs at a higher fuel flow rate. In the natural flickering regime, the dominating frequency of flame flickering remains within a small range, 12.5 Hz to 15 Hz, for all the burners and for all fuel flow rates. The time-averaged flame length-scale parameters, such as the maximum and the minimum flame heights, increase with respect to the fuel flow rate, however, the difference in the maximum and the minimum flame heights remains almost constant.

Characterization of surface position in a liquid dispensing orifice

Energy Technology Data Exchange (ETDEWEB)

Farahi, R H [ORNL; Passian, Ali [ORNL; Thundat, Thomas George [ORNL; Lereu, Aude L [ORNL; Tetard, Laurene [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Jones, Yolanda [ORNL

2009-01-01

Precision microdispencing technology delivers picoliter amounts of fluid for printing, electronic, optical, chemical and biomedical applications. In particular, microjetting is capable of accurate, flexible, and non-contact coating with polymers, thus allowing the functionalization of delicate microsensors such as microcantilevers. Information on various phases of droplet formation are important to control volume, uniformity, velocity and rate. One such aspect is the ringing of the meniscus after droplet breakoff which can affect subsequent drop formation. We present analysis of an optical characterization technique and experimental results on the behaviour of menisus oscillations in an orifice of a piezoelectric microjet.

Percutaneous transluminal angioplasty combining intraarterial drug perfusion for the treatment of chronic lower limb ischemia

International Nuclear Information System (INIS)

Liu Yuan; He Chunshui; Liao Huaqiang; Zeng Wei; Zhang Hongwei; Liu Yang; Mu Yan; Liao Huaqiang; Guan Yongsong

2008-01-01

Objective: To evaluate the clinical effects of balloon angioplasty in combination with intraarterial perfusion of vasoactive drugs in the treatment of chronic lower limb ischemia. Methods: A total of 21 patients were treated with percutaneous transfemoral or transaxillary approach of balloon dilatation of the occlusive arterial segments, and then followed by perfusion of urokinase, Lipo prostaglandin E 1 and ginkgo leaf injection, respectively, into the responsible arteries via the catheter. Postoperatively, some of the patients with tibioperoneal arteries occlusion were perfused with the same drugs into their diseased arterial segments, one time per day altogether 5-7 times, through the ipsilateral femoral arterial sheath reserved temporarily, and then followed by observation for improvement of ischemia, superficial ulceration and gangrenous change. Results: Of the 21 patients, 20 were successfully treated with percutaneous transluminal balloon dilation and arterial perfusion with a technical successful rate of 95.2% (20/21). Five of the total 20 were additionally treated with the same drugs perfusion 5-7 days through the retained sheath, showing well patency. No serious complications occurred and ischemic symptoms of limbs improved, such as rest pain, claudication and dermo temperature. During 2-7 months follow-up, healing of skin ulcer occurred in 4 patients and breakoff of necrotic digits in 2 with the surface wound healed. Necrotic toes in all patients were dehydrated with stopping of necrosis and without any amputation. Conclusions: Percutaneous transluminal angioplasty combining intraarterial drug perfusion is safe and effective for promoting blood circulation with healing of ulceration and ceasing the development of lesions; with furthermore of maintaining the arterial patency through the retained vascular sheath for sustaining the drug plerfusion. (authors)

Percutaneous Transluminal Angioplasty for Complete Membranous Obstruction of Suprahepatic Inferior Vena Cava: Long-Term Results

Energy Technology Data Exchange (ETDEWEB)

Kucukay, Fahrettin, E-mail: fkucukay@hotmail.com [Turkiye Yuksek Ihtisas Hospital, Department of Interventional Radiology (Turkey); Akdogan, Meral, E-mail: akdmeral@yahoo.com [Turkiye Yuksek Ihtisas Hospital, Department of Gastroenterology (Turkey); Bostanci, Erdal Birol, E-mail: ebbostanci@yahoo.com [Turkiye Yuksek Ihtisas Hospital, Department of Gastrointestinal Surgery (Turkey); Ulus, Ahmet Tulga, E-mail: uluss@yahoo.com [Hacettepe University, Department of Cardiovascular Surgery (Turkey); Kucukay, Murat Bulent, E-mail: dr-mbk@hotmail.com [Lokman Hekim Hospital, Department of Internal Medicine (Turkey)

2016-10-15

PurposeTo determine the long-term results of percutaneous transluminal angioplasty (PTA) for a complete membranous obstruction of the suprahepatic inferior vena cava.MethodsPatients (n = 65) who were referred to the interventional unit for PTA for a complete membranous obstruction of the suprahepatic inferior vena cava between January 2006 and October 2014 were included in the study. Thirty-two patients (18 males, 14 females, mean age 35 ± 10.7, range 20–42 years) were treated. The patients presented with symptoms of ascites (88 %), pleural effusion (53 %), varicose veins (94 %), hepatomegaly (97 %), abdominal pain (84 %), and splenomegaly (40 %). Transjugular liver access set and re-entry catheter were used to puncture and traverse the obstruction from the jugular side. PTA balloon dilations were performed. The mean follow-up period was 65.6 ± 24.5 months. The objective was to evaluate technical success, complications, primary patency, and clinical improvement in the symptoms of the patients.ResultsThe technical success rate was 94 %. In two patients, obstruction could not be traversed. These patients underwent cavoatrial graft bypass surgery. There were no procedure-related complications. Clinical improvements were achieved in all patients within 3 months. The primary patency rate at 4 years was 90 %. There was no primary assisted patency. There was no need for metallic stent deployment in the cohort. The secondary patency rate at 4 years was 100 %.ConclusionsPercutaneous transluminal angioplasty for a complete membranous obstruction of the suprahepatic inferior vena cava is safe and effective, and the long-term results are excellent.

A comphrehensive model for the amplification of acoustic pressure waves by single hole orifices

NARCIS (Netherlands)

Moussou, P.; Testud, Ph.; Auregan, Y.; Hirschberg, A.

2008-01-01

Using a parallel flow approximation, a simple model of hydrodynamic instability is proposed for describing the behavior of an orifice as an acoustic amplifier. It is shown that the growing of perturbations in the vena contracta can generate negative damping for Strouhal numbers of the order of

The whistling potentiality of an orifice in a confined flow using an energetic criterion

NARCIS (Netherlands)

Testud, P.; Aurégan, Y.; Moussou, P.; Hirschberg, A.

2009-01-01

Using a two-source method, the scattering matrices of 10 sharp-edged thin orifices are measured under different subsonic flow conditions. The data are analysed in terms of net acoustical energy balance: the potential whistling frequency range is defined as the one associated with acoustical energy

The usefulness of percutaneous transluminal angioplasty of the middle cerebral artery stenosis in patients with transient ischemic attack

Energy Technology Data Exchange (ETDEWEB)

Lee, Young Chul; Lim, Hyo Soon; Kim, Jae Kyu; Seo, Jeong Jin; Jeong, Gwang Woo; Kang, Heoung Keun [Chonnam National Univ. Medical School, Kwangju (Korea, Republic of)

2001-06-01

To determine the effectiveness of percutaneous transluminal angioplasty(PTA) of atherosclerotic middle cerebral artery(MCA) stenosis in patients with transient ischemic attack (TIA). Ten patients with TIA who had undergone PTA were retrospectively investigated. In all ten, angiography revealed stenosis of the MCA. Mechanical dilatation was performed at the stenotic portion, and the angiographic findings after PTA, as well as peri/post-angioplastic complications, were evaluated. Four to 64 (mean, 23.5) months later, neurologic symptoms and the nature and timing of recurrent attacks were also assessed. The degree of stenosis before PTA was 50-75% in six patients and greater than 75% in four. Complete or partial angiographic recanalization of the stenotic segment occurred in nine patients (90%). During follow-up, seven patients recovered without recurrent TIA or cerebral stroke; one reported a tingling sensation and one experienced vertebrobasilar insufficiency. Motor aphasia developed in one patient after PTA, but after systemic heparinization, improved within 24 hours. One patient who suffered intracranial hemorrhage due to vascular rupture during PTA did three days later. PTA for atherosclerotic MCA stenosis in patients with TIA is an effective therapeutic method.

The usefulness of percutaneous transluminal angioplasty of the middle cerebral artery stenosis in patients with transient ischemic attack

International Nuclear Information System (INIS)

Lee, Young Chul; Lim, Hyo Soon; Kim, Jae Kyu; Seo, Jeong Jin; Jeong, Gwang Woo; Kang, Heoung Keun

2001-01-01

To determine the effectiveness of percutaneous transluminal angioplasty(PTA) of atherosclerotic middle cerebral artery(MCA) stenosis in patients with transient ischemic attack (TIA). Ten patients with TIA who had undergone PTA were retrospectively investigated. In all ten, angiography revealed stenosis of the MCA. Mechanical dilatation was performed at the stenotic portion, and the angiographic findings after PTA, as well as peri/post-angioplastic complications, were evaluated. Four to 64 (mean, 23.5) months later, neurologic symptoms and the nature and timing of recurrent attacks were also assessed. The degree of stenosis before PTA was 50-75% in six patients and greater than 75% in four. Complete or partial angiographic recanalization of the stenotic segment occurred in nine patients (90%). During follow-up, seven patients recovered without recurrent TIA or cerebral stroke; one reported a tingling sensation and one experienced vertebrobasilar insufficiency. Motor aphasia developed in one patient after PTA, but after systemic heparinization, improved within 24 hours. One patient who suffered intracranial hemorrhage due to vascular rupture during PTA did three days later. PTA for atherosclerotic MCA stenosis in patients with TIA is an effective therapeutic method

Assessment of percutaneous transluminal coronary angioplasty with 123IODO-heptadecanoic acid

International Nuclear Information System (INIS)

Stoddart, P.G.P.; Wilde, P.; Papouchado, M.; Jones, J.V.

1987-01-01

Ten patients underwent myocardial scintigraphy with 123 I-iodo-heptadecanoic acid (HDA), which was injected in the last minute of maximal exercise testing. Six of the patients were rescanned following percutaneous transluminal coronary angioplasty. All ten patients underwent full coronary angiography. There were visible perfusion defects on the static images in 74% of the myocardial areas which were supplied by an artery with a stenosis greater than 75%. The mean half life recorded from areas distal to an arterial stenosis of at least 90% (35.69 min±41.25 min), was longer than the expected normal mean (18.85 min±3.35 min). However, the difference was not statistically significant. The static images changed in some patients following angioplasty, however there was no consistent alteration in the half-lives. It was concluded that HDA is a suitable agent for investigating myocardial perfusion, but that the half life cannot be measured adequately for clinical purposes with a planar imaging sytsem. (orig.)

Optimization and audit of radiation dose during percutaneous transluminal coronary angioplasty

International Nuclear Information System (INIS)

Livingstone, Roshan S.; Timothy Peace, B.S.; Chandy, Sunil; Gorge, Paul V.; Pati, Purendra

2007-01-01

The percutaneous transluminal coronary angioplasty (PTCA) is one of the interventional procedures which impart high radiation doses to patients compared to the other cardiologic procedures. This study intends to audit and optimize radiation dose imparted to patients undergoing PTCA. Forty-four patients who underwent PTCA involving single or multiple stent placement guided under cardiovascular X-ray machine were included in the study. Radiation doses were measured using dose area product (DAP) meter for patients undergoing single and multiple stent placements during PTCA. A dose reduction of 27-47% was achieved using copper filters and optimal exposure parameters. The mean DAP values before optimization were 66.16 and 122.68 Gy cm 2 for single and multiple stent placement respectively. These values were 48.67 and 65.44 Gy cm 2 respectively after optimization. In the present scenario, due to the increase in the number of PTCAs performed and the associated risk from radiation, periodical audit of radiation doses for interventional procedures are recommended. (author)

Experimental otitis media with effusion induced by electron beam irradiation to pharyngeal orifice of auditory tube in guinea pig

International Nuclear Information System (INIS)

Kokubu, Michiyo; Amatsu, Mutsuo

1984-01-01

The purpose of the present study was to obtain a more natural tubal insufficiency than that obtained by the conventional methods to clarify the middle ear pathology associated with tubal dysfunction. For this purpose, the pharyngeal orifice of the auditory tube in the guinea pigs was irradiated with electron beam with a dose of 2,000 rad following the preliminary experiments to determine the appropriate dose. The guinea pigs with intact drum and normal Pryer reflex were used for the present experiment series. A specially devised apparatus was used for avoiding the dipersing beam. Histopathological changes of the middle ear and auditory tube were observed in a series of single specimen with H-E staining 1, 2, 3, 6, 12 months after irradiation. In this study, middle ear with effusion was used to clarify the dynamic process of the pathological changes between the auditory tube and the middle ear. In summary, the present study revealed that the electron beam irradiation to the pharyngeal orifice caused various grades of otitis media with effusion which could be classified into three groups. Of these groups 1) and 2), 3) were likely to be corresponding with so-called serous and purulent otitis media with effusion in human respectively. Infection due to the malfunction caused by the epithelial damage of the auditory tube was an important promoting factor to change the serous type effusion for the purulent type effusion. (J.P.N.)

A double parameters measurement of steam-water two-phase flow with single orifice

International Nuclear Information System (INIS)

Zhong Shuoping; Tong Yunxian; Yu Meiying

1992-08-01

A double parameters measurement of steam-water two-phase flow with single orifice is described. An on-line measurement device based on micro-computer has been developed. The measured r.m.s error of steam quality is less than 6.5% and the measured relative r.m.s. error of mass flow rate is less than 9%

Percutaneous Transluminal Angioplasty and Enclosed Thrombolysis Versus Percutaneous Transluminal Angioplasty in the Treatment of Femoropopliteal Occlusions: Results of a Prospective Randomized Trial

International Nuclear Information System (INIS)

Nicholson, Tony

1998-01-01

Purpose: To determine whether percutaneous transluminal angioplasty (PTA) and enclosed thrombolysis (ET) is superior to PTA alone in the treatment of femoropopliteal occlusions. Methods: Twenty-five patients with 5-15-cm-long occlusions in the femoropopliteal segments, with otherwise normal run-in arteries and at least one normal tibioperoneal artery to the foot, were randomized to ET/PTA or PTA alone. Ankle brachial systolic index (ABI) was measured before the procedure and at 24 hr and 12 months after the procedure, when a duplex scan was also carried out. End points in the study were patency at, or repeat intervention before, 12 months. Results: Procedures were successful in 23 of 25 patients. There was one immediate occlusion of tibioperoneal arteries, and one early reocclusion of a reopened segment in the ET/PTA group. There was one early reocclusion in the PTA group. At 12 months patency was 70% and 69.2% in the ET/PTA and PTA groups respectively. Covariant analysis showed no significant difference in ABI between the two groups at any of the three measurement times. Conclusion: This trial demonstrated no difference between ET/PTA and PTA alone in femoropopliteal occlusions associated with normal proximal arteries and at least one normal tibioperoneal artery

Method for generating small and ultra small apertures, slits, nozzles and orifices

Science.gov (United States)

Khounsary, Ali M [Hinsdale, IL

2012-05-22

A method and device for one or more small apertures, slits, nozzles and orifices, preferably having a high aspect ratio. In one embodiment, one or more alternating layers of sacrificial layers and blocking layers are deposited onto a substrate. Each sacrificial layer is made of a material which preferably allows a radiation to substantially pass through. Each blocking layer is made of a material which substantially blocks the radiation.

Orifice microreactor for the production of an organic peroxide – non-reactive and reactive characterization

NARCIS (Netherlands)

Illg, T.; Hessel, V.; Löb, P.; Schouten, J.C.

2012-01-01

In this article, the transfer of a two-step, biphasic, and exothermic peroxide synthesis into a microreactor assisted process is discussed as well as the non-reactive and reactive characterization of the developed orifice microreactor. Residence time distribution measurements showed nearly ideal

Gonioscopy-assisted Transluminal Trabeculotomy (GATT): Thermal Suture Modification With a Dye-stained Rounded Tip.

Science.gov (United States)

Grover, Davinder S; Fellman, Ronald L

2016-06-01

To describe a novel technique for thermally marking the tip of a suture, in preparation for a gonioscopy-assisted transluminal trabeculotomy. One patient was used as an example for this technique. Technique report. The authors introduce a modification of a novel surgical procedure (GATT) in which a suture is marked and thermally blunted allowing a proper visualization while performing an ab interno, minimally invasive, circumferential 360-degree suture trabeculotomy. The authors have previously reported on the GATT surgery with the use of an illuminated microcatheter, which allowed for visualization of the tip of the catheter as it circumnavigated Schlemm canal. This modification allows for similar visualization of the tip of the suture, however, is much more cost-effective while still maintaining similar safety.

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.

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.

Submucosal tunneling techniques: current perspectives.

Science.gov (United States)

Kobara, Hideki; Mori, Hirohito; Rafiq, Kazi; Fujihara, Shintaro; Nishiyama, Noriko; Ayaki, Maki; Yachida, Tatsuo; Matsunaga, Tae; Tani, Johji; Miyoshi, Hisaaki; Yoneyama, Hirohito; Morishita, Asahiro; Oryu, Makoto; Iwama, Hisakazu; Masaki, Tsutomu

2014-01-01

Advances in endoscopic submucosal dissection include a submucosal tunneling technique, involving the introduction of tunnels into the submucosa. These tunnels permit safer offset entry into the peritoneal cavity for natural orifice transluminal endoscopic surgery. Technical advantages include the visual identification of the layers of the gut, blood vessels, and subepithelial tumors. The creation of a mucosal flap that minimizes air and fluid leakage into the extraluminal cavity can enhance the safety and efficacy of surgery. This submucosal tunneling technique was adapted for esophageal myotomy, culminating in its application to patients with achalasia. This method, known as per oral endoscopic myotomy, has opened up the new discipline of submucosal endoscopic surgery. Other clinical applications of the submucosal tunneling technique include its use in the removal of gastrointestinal subepithelial tumors and endomicroscopy for the diagnosis of functional and motility disorders. This review suggests that the submucosal tunneling technique, involving a mucosal safety flap, can have potential values for future endoscopic developments.

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.

Periodic cavitation shedding in a cylindrical orifice

Energy Technology Data Exchange (ETDEWEB)

Stanley, C.; Barber, T.; Milton, B.; Rosengarten, G. [University of New South Wales, School of Mechanical and Manufacturing Engineering, Sydney (Australia)

2011-11-15

Cavitation structures in a large-scale (D = 8.25 mm), plain orifice style nozzle within a unique experimental rig are investigated using high-speed visualisation and digital image processing techniques. Refractive index matching with an acrylic nozzle is achieved using aqueous sodium iodide for the test fluid. Cavitation collapse length, unsteady shedding frequency and spray angles are measured for cavitation conditions from incipient to supercavitation for a range of Reynolds numbers, for a fixed L/D ratio of 4.85. Periodic cavitation shedding was shown to occur with frequencies between 500 and 2,000 Hz for conditions in which cavitation occupied less than 30% of the nozzle length. A discontinuity in collapse length was shown to occur once the cavitation exceeded this length, coinciding with a loss of periodic shedding. A mechanism for this behaviour is discussed. Peak spray angles of approximately {theta} {approx} 14 were recorded for supercavitation conditions indicating the positive influence of cavitation bubble collapse on the jet atomisation process. (orig.)

Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device

International Nuclear Information System (INIS)

Papell, S.S.; Nyland, T.W.; Saiyed, N.H.

1992-07-01

Liquid hydrogen mass flow rate, pressure drop, and temperature drop data were obtained for a number of multiple orifice Joule-Thomson devices known as visco jets. The present investigation continues a study to develop an equation for predicting two phase flow of cryogens through these devices. The test apparatus design allowed isenthalpic expansion of the cryogen through the visco jets. The data covered a range of inlet and outlet operating conditions. The mass flow rate range single phase or two phase was 0.015 to 0.98 lbm/hr. The manufacturer's equation was found to overpredict the single phase hydrogen data by 10 percent and the two phase data by as much as 27 percent. Two modifications of the equation resulted in a data correlation that predicts both the single and two phase flow across the visco jet. The first modification was of a theoretical nature, and the second strictly empirical. The former reduced the spread in the two phase data. It was a multiplication factor of 1-X applied to the manufacturer's equation. The parameter X is the flow quality downstream of the visco jet based on isenthalpic expansion across the device. The latter modification was a 10 percent correction term that correlated 90 percent of the single and two phase data to within +/- 10 percent scatter band. 3 refs

Percutaneous transluminal angioplasty in the region of the renal artery: indications, technique and results

Energy Technology Data Exchange (ETDEWEB)

Olbert, F; Ogris, E; Muzika, N; Schlegl, A; Vacariu, O; Diez, W

1985-01-01

The paper reports the results obtained by percutaneous transluminal angioplasty (PTA) in the treatment of renal artery stenosis in 25 patients with secondary hypertension and discusses indications and the technique used. The follow-up period ranged from 0.5 to 12 months. All interventions were performed with the Olbert catheter system. Following PTA a significant decrease in systolic, diastolic and mean arterial pressure was observed in nearly all patients. The response of the plasma renin activity (PRA) to orthostatic stimulation and pharmacological stimulation by furosemide was determined in a subset of 15 patients before and after PTA. A significant decrease in both basal and stimulated PRA values was observed subsequent to PTA. The decrease in PRA values after successful PTA did not, however, correlate with the extent of the blood pressure changes. (Author).

Percutaneous transluminal angioplasty in the region of the renal artery: indications, technique and results

International Nuclear Information System (INIS)

Olbert, F.; Ogris, E.; Muzika, N.; Schlegl, A.; Vacariu, O.; Diez, W.

1985-01-01

The paper reports the results obtained by percutaneous transluminal angioplasty (PTA) in the treatment of renal artery stenosis in 25 patients with secondary hypertension and discusses indications and the technique used. The follow-up period ranged from 0.5 to 12 months. All interventions were performed with the Olbert catheter system. Following PTA a significant decrease in systolic, diastolic and mean arterial pressure was observed in nearly all patients. The response of the plasma renin activity (PRA) to orthostatic stimulation and pharmacological stimulation by furosemide was determined in a subset of 15 patients before and after PTA. A significant decrease in both basal and stimulated PRA values was observed subsequent to PTA. The decrease in PRA values after successful PTA did not, however, correlate with the extent of the blood pressure changes. (Author)

Quantitative analysis of the side-branch orifice after bifurcation stenting using en-face processing of OCT images: a comparison between Xience V and Resolute Integrity stents.

Science.gov (United States)

Minami, Yoshiyasu; Wang, Zhao; Aguirre, Aaron D; Lee, Stephen; Uemura, Shiro; Soeda, Tsunenari; Vergallo, Rocco; Raffel, Owen C; Barlis, Peter; Itoh, Tomonori; Lee, Hang; Fujimoto, James; Jang, Ik-Kyung

2016-01-01

Methods for intravascular assessment of the side-branch (SB) orifice after stenting are not readily available. The aim of this study was to assess the utility of an en-face projection processing for optical coherence tomography (OCT) images for SB evaluation. Measurements of the SB orifice obtained using en-face OCT images were validated using a phantom model. Linear regression modeling was applied to estimated area measurements made on the en-face images. The SB orifice was then analyzed in 88 patients with bifurcation lesions treated with either Xience V (everolimus-eluting stent) or Resolute Integrity [zotarolimus-eluting stent (ZES)]. The SB orifice area (A) and the area obstructed by struts (B) were calculated, and the %open area was evaluated as (A-B)/A*100. Linear regression modeling demonstrated that the observed departures of the intercept and slope were not significantly different from 0 (-0.12 ± 0.22, P=0.59) and 1 (1.01 ± 0.06, R(2)=0.88, P=0.87), respectively. In cases without SB dilatation, the %open area was significantly larger in the everolimus-eluting stent group (n=25) than in the ZES group [n=32; 89.2% (83.7-91.3) vs. 84.3% (78.9-87.8), P=0.04]. A significant difference in %open area between cases with and those without SB dilatation was demonstrated in the ZES group [91.4% (86.1-94.0) vs. 84.3% (78.9-87.8), P=0.04]. The accuracy of SB orifice measurement on an en-face OCT image was validated using a phantom model. This novel approach enables quantitative evaluation of the differences in SB orifice area free from struts among different stent types and different treatment strategies in vivo.

A case of ectopic ureteral orifice with hypoplastic kidney diagnosed by enhanced computed tomography

International Nuclear Information System (INIS)

Kishi, Mikio; Yoshimoto, Jun; Matsumura, Yosuke; Ohmori, Hiroyuki

1983-01-01

A case of ectopic ureteral orifice, 6 year old girl with urinary incontinece, is herein reported. Cystoscopy and excretory urogram showed absense of right half of trigone and non visualizing kidney. By enhanced computed tomography, right hypoplastic kidney was found and right nephrectomy was performed. We emphasize that enhanced computed tomography is very usefull for diagnosis of localization of hypoplastic kidney. (author)

Combined experimental and computational investigation of the cavitating flow in an orifice plate with special emphasis on surrogate-based optimization method

International Nuclear Information System (INIS)

Li, XianLin; Huang, Biao; Chen, Tairan; Liu, Ying; Qiu, Si Cong; Zhao, Jing

2017-01-01

We investigated the influence of geometrical parameters of the orifice plate on the cavitation structures, and optimized these parameters by using a surrogate-based model with special emphasis on the concentration of hydroxyl radical released. The results show that for the orifice plate of the hydrodynamic cavitation system, the possible location of the inception of the cavity spreads to throat and divergent section of the venturi geometry. Based on the surrogate model and global sensitivity assessment, the diameter of throat Dt and diameter of inlet Din significantly influenced the size of the cavity, while the length of throat Lt had little effect on both cavitation intensity and flow rate. It should be noted that when Lt is decreased, the size of cavity would be slightly decreased but the flow rate increased clearly. The increase of the diverging section is in favor of the size of cavity. By comparing the experimental measurements on the concentration of Methylene blue, the optimum geometry of the orifice plate for best cavitational activity is proposed

Combined experimental and computational investigation of the cavitating flow in an orifice plate with special emphasis on surrogate-based optimization method

Energy Technology Data Exchange (ETDEWEB)

Li, XianLin; Huang, Biao; Chen, Tairan; Liu, Ying; Qiu, Si Cong [School of Mechanical and Vehicular Engineering, Beijing Institute of Technology, Beijing (China); Zhao, Jing [China Academy of Launch Vehicle Technology, Beijing (China)

2017-01-15

We investigated the influence of geometrical parameters of the orifice plate on the cavitation structures, and optimized these parameters by using a surrogate-based model with special emphasis on the concentration of hydroxyl radical released. The results show that for the orifice plate of the hydrodynamic cavitation system, the possible location of the inception of the cavity spreads to throat and divergent section of the venturi geometry. Based on the surrogate model and global sensitivity assessment, the diameter of throat Dt and diameter of inlet Din significantly influenced the size of the cavity, while the length of throat Lt had little effect on both cavitation intensity and flow rate. It should be noted that when Lt is decreased, the size of cavity would be slightly decreased but the flow rate increased clearly. The increase of the diverging section is in favor of the size of cavity. By comparing the experimental measurements on the concentration of Methylene blue, the optimum geometry of the orifice plate for best cavitational activity is proposed.

Dual discharge from a stratified two-phase region through side orifices oriented horizontally

Energy Technology Data Exchange (ETDEWEB)

Hassan, I G; Soliman, H M; Sims, G E [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Mechanical Engineering; Kowalski, J E [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

1996-12-31

Experimental data are presented for the mass flow rate and quality of two-phase (air-water) discharge from a stratified region through two side orifices (6.35 mm i.d.) with their parallel centre lines located in a horizontal plane. These data correspond to different values of the interface level between the onsets of gas and liquid entrainments for test-section pressures of 316 and 517 kPa, test-section-to-separators pressure difference ranging from 40 to 235 kPa, orifice separating distance to diameter ratio ranging from 1.5 to 8 and different hydraulic resistances of the lines connecting the test section to the separators. Influences of these independent variables on the deviation between the present results (of mass flow rate and quality) and those corresponding to a single discharge are presented and discussed. Normalized plots are presented showing that the present data of dual discharge and those of a single discharge can be collapsed for the whole test range when specific definition for the dimensionless height of the interface and mass flow rate are used. Excellent agreement is demonstrated between single-discharge correlations and the present data using these dimensionless quantities. (author). 12 refs., 1 tab., 16 figs.

Dual discharge from a stratified two-phase region through side orifices oriented horizontally

International Nuclear Information System (INIS)

Hassan, I.G.; Soliman, H.M.; Sims, G.E.; Kowalski, J.E.

1995-01-01

Experimental data are presented for the mass flow rate and quality of two-phase (air-water) discharge from a stratified region through two side orifices (6.35 mm i.d.) with their parallel centre lines located in a horizontal plane. These data correspond to different values of the interface level between the onsets of gas and liquid entrainments for test-section pressures of 316 and 517 kPa, test-section-to-separators pressure difference ranging from 40 to 235 kPa, orifice separating distance to diameter ratio ranging from 1.5 to 8 and different hydraulic resistances of the lines connecting the test section to the separators. Influences of these independent variables on the deviation between the present results (of mass flow rate and quality) and those corresponding to a single discharge are presented and discussed. Normalized plots are presented showing that the present data of dual discharge and those of a single discharge can be collapsed for the whole test range when specific definition for the dimensionless height of the interface and mass flow rate are used. Excellent agreement is demonstrated between single-discharge correlations and the present data using these dimensionless quantities. (author). 12 refs., 1 tab., 16 figs

Iatrogenic Subtotal Stenosis of the Right Subclavian Artery Treated With Percutaneous Transluminal Angioplasty

International Nuclear Information System (INIS)

Smeenk, Robert M.; Kock, Mark C. J. M.; Elgersma, Otto E. H.; Schnater, Marco J.

2011-01-01

This report describes a rare vascular complication of surgical placement of a marking clip and a possible approach to problem solving. A 55-year-old patient presented with loss of sensation in the fingers and loss of peripheral pulsations in the right arm 4 days after right upper lobectomy for a pT2N1 moderately differentiated adenocarcinoma of the lung. Duplex examination and computed tomography were performed the same day and showed a subtotal stenosis of the right subclavian artery, which was caused by the surgical placement of a metal clip to mark the surgical boundary. Selective angiography was subsequently performed. Percutaneous transluminal angioplasty (PTA) successfully dilated the stenosis and pushed the clip off. Flow in the right subclavian artery (RSA) was completely restored as were neurology and peripheral pulses. In conclusion, arterial stenosis by a surgical (marking) clip may be feasibly treated with PTA.

Clinical application of Inoue-balloon in percutaneous transluminal angioplasty for Budd-Chiari syndrome

International Nuclear Information System (INIS)

Mei Jian; Qu Jian; Zhu Yaoqing; Wang Lei; Liu Cheng

2007-01-01

Objective: To investigate the feasibility and effect of recanalization of inferior vena cava with percutaneous transluminal angioplasty(PTA)by Inoue-balloon. Methods: Eighty-nine patients with Budd-chiari syndrome (BCS )were treated with PTA by Inoue-balloon. Results: After PTA, the median (interquartile range)diameter of hepatic segment inferior vena cava increased from 0.00 (0.20-0.00) cm to 1.90 (2.00 1.47)cm; (P < 0.001), and the mean pressure of inferior vena cava reduced from (20.63 ± 7.22) mmHg to (12.13 ± 5.60) mmHg; (P < 0.001); with only less serious complications as rupture in two cases and without need of prior minor diameter balloon dilation in Inoue-balloon PTA. Conclusion: The advantages of Inoue- balloon PTA for BCS are more reliable and facile than those of polyethylene balloon, and may take the place in the foreseen future. (authors)

Aggressive nonsurgical management of acute coronary artery occlusions developing immediately after percutaneous transluminal coronary angioplasty (PTCA)

International Nuclear Information System (INIS)

Levin, D.C.; Meyerovitz, M.; Boxt, L.; Taus, R.; Ganz, P.; Friedman, P.; Selwyn, A.

1986-01-01

In 368 consecutive percutaneous transluminal coronary angiography (PTCA) procedures, acute occlusion of the dilated artery developed within the first hour after the procedure in 24 cases (6.5%). Four patients underwent emergency bypass surgery. In 17 of the remaining 20 patients, repeat balloon dilation was immediately attempted, and was successful in 11 instances (65%). Five of the six cases in which repeat balloon dilation was not successful responded well to surgical or medical therapy. The author conclude that acute occlusions of dilated coronary arteries shortly after PTCA do not automatically necessitate emergency bypass. Approximately two thirds of such cases can be managed by repeat dilation, converting a potential complication into a successful outcome

The Performance Test for Reactor Coolant Pump (RCP) adopting Variable Restriction Orifice Type Control Valve

Energy Technology Data Exchange (ETDEWEB)

Kim, S.; Bae, B. U.; Cho, Y. J. and others

2014-05-15

The design values of the RCPTF are 17.2 MPa, 343 .deg. C, 11.7 m{sup 3}/s, and 13 MW in the maximum pressure, temperature, flow rate, and electrical power, respectively. In the RCPTF, various types of tests can be performed including a hydraulic performance test to acquire a H-Q curve as well seal transient tests, thrust bearing transient test, cost down test, NPSHR verification test, and so on. After a commissioning startup test was successfully perfomed, mechanical structures are improved including a flow stabilizer and variable restriction orifice. Two- branch pipe (Y-branch) was installed to regulate the flow rate in the range of performance tests. In the main pipe, a flow restrictor (RO: Restriction Orifice) for limiting the maximum flow rate was installed. In the branch pipe line, a globe valve and a butterfly valves for regulating the flow rate was located on the each branch line. When the pressure loss of the valve side is smaller than that of the RO side, the flow rate of valve side was increasing and the flow disturbance was occurred in the lower pipe line. Due to flow disturbnace, it is to cause an error when measuring RCP head and flow measurement of the venturi flow meter installed in the lower main pipe line, and thus leading to a decrease in measurement accuracy as a result. To increase the efficiency of the flow control availability of the test facility, the variable restriction orifice (VRO) type flow control valve was designed and manufactured. In the RCPTF in KAERI, the performance tests and various kinds of transient tests of the RCP were successfully performed. In this study, H-Q curve of the pump using the VRO revealed a similar trend to the result from two ROs. The VRO was confirmed to effectively cover the full test range of the flow rate.

Nuclear medical quality control of transluminal coronary angioplastic (TCA)

International Nuclear Information System (INIS)

Klepzig, H. Jr.; Scherer, D.; Kober, G.; Kaltenbach, M.; Maul, F.D.; Standke, R.; Hoer, G.; Kanemoto, N.

1984-01-01

To assess the results of transluminal coronary angioplasty 48 patients with coronary heart disease were investigated at rest and during exercise with the ECG (46 patients), thallium-201 myocardial scintigraphy (26 patients), and equilibrium radionuclide ventriculography (38 patients). Exercise stress test was quantified by means of an ischemia score, myocardial scintigraphy by an vitality index and by corresponding redistribution factors, and radionuclide ventriculography by ejection fraction and maximum systolic volume change as a fraction of enddiastolic volume. The patients were divided into three groups: 36 patients had successful TCA (group 1); 6 patients underwent aortocoronary bypass operation (ACB, group 2); in 6 patients TCA was unsuccessful, they served as control (group 3). On average TCA yielded a reduction of coronary artery stenosis from 83% to 44%. Functional improvement was comparable in group 1 and 2: Ischemia score was reduced significantly. Perfusion index increased, the corresponding redistribution factors decreased. Left ventricular ejection fraction increased at rest and during exercise. Maximum systolic volume change increased correspondingly. Only slight changes were noted in group 3. Three months later 2 of 16 reinvestigated patients showed a restenosis and one a new narrowing distal to the successfully dilated stenosis. Functional deterioration could be demonstrated in these, whilst maintainance of the good functional results was documented in the others. (orig./MG) [de

Exercise electrocardiography and myocardial scintigraphy in the serial evaluation of the results of percutaneous transluminal coronary angioplasty

International Nuclear Information System (INIS)

Schall, J.M.; Chaitman, B.R.; David, P.R.; Dupras, G.; Brevers, G; Val, P.G.; Crepeau, J.; Lesperance, J.; Bourassa, M.G.

1982-01-01

The diagnostic value of exercise electrocardiography using 14 leads and thallium-201 scintigraphy were evaluated in 54 of 70 patients who underwent percutaneous transluminal coronary angioplasty (PTCA), both in the initial assessment and serial follow-up of patients after PTCA. Of the 45 patients who had successful PTCA, 36 had complete noninvasive studies performed before and 1 month after PTCA. The use of clinical symptoms in conjunction with the physiologic data, ECG and myocardial scintigram acquired during exercise provide important short-term data on the angiographic evolution of PTCA results. The noninvasive tests may be useful in determining guidelines for repeat angiography in patients who have had PTCA

Long-term outcome of endovascular treatment versus medical care for carotid artery stenosis in patients not suitable for surgery and randomised in the Carotid and Vertebral Artery Transluminal Angioplasty study (CAVATAS).

LENUS (Irish Health Repository)

Ederle, Jörg

2009-01-01

Optimal treatment of carotid stenosis in patients not suitable for surgery is unclear. The Carotid and Vertebral Artery Transluminal Angioplasty study contained a trial comparing medical and endovascular treatment in patients not suitable for surgery.

Comparative Performance of a Non-recessed Hole-entry Hybrid/Hydrostatic Conical Journal Bearing Compensated with Capillary and Orifice Restrictors

Directory of Open Access Journals (Sweden)

P.G. Khakse

2016-06-01

Full Text Available This research paper deals with the theoretical study of comparison of capillary and orifice compensated non-recess hole-entry hydrostatic/ hybrid conical journal bearing. Modified Reynolds equation governing the flow of lubricant in the clearance space of conical journal and bearing has been solved using FEM, Newton-Raphson method and Gauss elimination method. Spherical coordinate system has been employed to obtain the results. The results have been computed for uniform distribution of holes in the circumferential direction with the range of restrictor design parameter C ̅_s2 = 0.02 - 0.1. The numerically simulated result shows, the use of orifice restrictor is to increase bearing stiffness, threshold speed and maximum pressure compared to capillary restrictor for applied radial load.

Close to Transplant Renal Artery Stenosis and Percutaneous Transluminal Treatment

Directory of Open Access Journals (Sweden)

Leonardou Polytimi

2011-01-01

Full Text Available Purpose. To evaluate the efficacy of percutaneous transluminal angioplasty (PTA in the management of arterial stenosis located close to the allograft anastomosis (close-TRAS. Materials and Methods. 31 patients with renal transplants were admitted to our institution because of persistent hypertension and impairment of transplant renal function and underwent angiography for vascular investigation. 27 were diagnosed suffering from transplant renal artery stenosis (TRAS, whereas 4 had severe iliac artery stenosis proximal to the transplant anastomosis (Prox-TRAS. 3 cases of TRAS coexisted with segmental renal arterial stenosis, whereas 3 other cases of TRAS were caused by kinking and focal stenosis in the middle of the transplanted renal artery. Results. Angioplasty and stenting were successfully applied to all patients with iliac artery stenosis as well as to those with TRAS and segmental artery stenosis. Two of three patients with kinking were well treated with angioplasty and stenting, whereas one treated only with angioplasty necessitated surgery. No major procedure-related complications appeared, and the result was decrease of the serum creatinine level and of the blood pressure. Conclusions. PTA is the appropriate initial treatment of TRAS and close-TRAS, with low morbidity and mortality rates, achieving improvement of graft function and amelioration of hypertension.

Diagnostic pure transgastric NOTES in an intensive therapy unit patient

Directory of Open Access Journals (Sweden)

Maciej Michalik

2011-06-01

Full Text Available Natural orifice transluminal endoscopic surgery (NOTES is a natural consequence of evolution in minimally invasivesurgery. It allows one to reduce surgical trauma and the number of complications and to improve cosmetic outcomes.It also shortens the patient’s recovery time. So far there have been only nine NOTES procedures performed in Polandand around 200 NOTES interventions performed worldwide. In this paper a transgastric diagnostic NOTES procedurein a critically ill patient is described. A 60-year-old male patient with multi-organ failure (circulatory, respiratory andrenal insufficiency, with co-morbid hypothyroidism and diabetes mellitus hospitalized in the intensive therapy unit(ITU with unknown cause of his condition was qualified for transgastric diagnostic NOTES procedure. This interventionrevealed the diagnosis of metastatic neoplastic disease and allowed persistent therapy to be avoided. DiagnosticNOTES in selected patients seems to be a very useful. It provides fast diagnosis with relatively small perioperativetrauma. It is an easy procedure that requires a regular or operative endoscope, one surgeon and an endoscopic nurse.It can be done anywhere, including at the patient’s bedside. It provides specimens for histopathology and speeds updiagnostics and decision making, especially in terminally ill patients.

Surgical Outcomes of Gonioscopy-assisted Transluminal Trabeculotomy (GATT) in Patients With Open-angle Glaucoma.

Science.gov (United States)

Rahmatnejad, Kamran; Pruzan, Noelle L; Amanullah, Sarah; Shaukat, Bilal A; Resende, Arthur F; Waisbourd, Michael; Zhan, Tingting; Moster, Marlene R

2017-12-01

To evaluate the efficacy and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) in patients with open-angle glaucoma. A retrospective chart review of adult patients who underwent GATT due to inadequately controlled intraocular pressure (IOP) or intolerance to medication. Main outcome measures were success rate, IOP, and number of glaucoma medications. Success was defined as IOP reduction >20% from baseline or IOP between 5 to 21 mm Hg, and no need for further glaucoma surgery. When success criteria were not met for any postoperative visit >3 months after surgery, failure was determined. In total, 66 patients, average age 62.9±14.9 years (50.8% female) were included in the analysis. Average follow-up was 11.9 months (range, 3 to 30 mo) and overall success rate was 63.0%. Mean IOP was 26.1±9.9 mm Hg preoperatively and 14.6±4.7 mm Hg at 12 months (44% IOP decrease; P<0.001). Mean number of medications decreased from 3.1±1.1 preoperatively to 1.2±0.9 at 12 months (P<0.001). No significant differences between patients with primary open-angle glaucoma and other types of glaucoma were found.The rate of hyphema at 1 week and 1 month postoperatively was 38% and 6%, respectively. Overall GATT success rate among white and black patients was 69% and 42%, respectively, which was statistically significant (P<0.05). The future of GATT as a minimally invasive glaucoma surgery in adults seems promising. This position is supported by its low rate of long-term complications and the conjunctiva-sparing nature of the surgery.

Needs analysis for developing a virtual-reality NOTES simulator.

Science.gov (United States)

Sankaranarayanan, Ganesh; Matthes, Kai; Nemani, Arun; Ahn, Woojin; Kato, Masayuki; Jones, Daniel B; Schwaitzberg, Steven; De, Suvranu

2013-05-01

INTRODUCTION AND STUDY AIM: Natural orifice translumenal endoscopic surgery (NOTES) is an emerging surgical technique that requires a cautious adoption approach to ensure patient safety. High-fidelity virtual-reality-based simulators allow development of new surgical procedures and tools and train medical personnel without risk to human patients. As part of a project funded by the National Institutes of Health, we are developing the virtual transluminal endoscopic surgery trainer (VTEST) for this purpose. The objective of this study is to conduct a structured needs analysis to identify the design parameters for such a virtual-reality-based simulator for NOTES. A 30-point questionnaire was distributed at the 2011 National Orifice Surgery Consortium for Assessment and Research meeting to obtain responses from experts. Ordinal logistic regression and the Wilcoxon rank-sum test were used for analysis. A total of 22 NOTES experts participated in the study. Cholecystectomy (CE, 68 %) followed by appendectomy (AE, 63 %) (CE vs AE, p = 0.0521) was selected as the first choice for simulation. Flexible (FL, 47 %) and hybrid (HY, 47 %) approaches were equally favorable compared with rigid (RI, 6 %) with p virtual NOTES simulator in training and testing new tools for NOTES were rated very high by the participants. Our study reinforces the importance of developing a virtual NOTES simulator and clearly presents expert preferences. The results of this analysis will direct our initial development of the VTEST platform.

Radiation dose to patients from the coronary angiography and percutaneous transluminal coronary angioplasty in interventional radiology procedures

International Nuclear Information System (INIS)

Zheng, Jun-Zheng; Bai, Mei; Liu, Bin

2008-01-01

Full text: Objective: To survey and assess radiation dose to patients from coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) in Beijing Xuanwu Hospital of Capital University of Medical Sciences. Methods: The dose-area product (DAP) values to the patient and cumulative dose (CD) were recorded from 84 coronary angiographies and 51 percutaneous transluminal coronary angioplasty. A Monte-Carlo based program PCXMC was used to calculate the effective dose from DAP values for each patient. Organ doses were also measured by thermoluminescent dosimeters (TLD) using a human-shaped phantom to compare the calculated organ dose from DAP. Results: The difference between the organ doses measured by TLDs and those from PCXMC software (P>0.05) were tolerable. The DAP value ranged from 7611∼60538 mGy·cm 2 for CA and 16423∼161973 mGy·cm 2 for PTCA. The effective dose for all procedures was determined to be in the range of 1.1∼6.9 mSv for CA and 2.3∼20.1 mSv for PTCA. CD ranged from 120.0 to 1016.0 mGy for CA and 287 to 2883 mGy for PTCA. Conversion factors between effective dose and DAP were 0.114∼0.139 mSv·Gy - 1·cm -2 for CA and 0.124∼0.142 mSv·Gy -1 ·cm -2 for PTCA; Conversion factors between organ dose and CD were derived for CA and PTCA, respectively. Conclusions: DAP and CD can be used as the dose indicator to calculate the organ dose and effective dose of patient based on Monte Carlo simulation. Using this method can provide important information of patient absorbed dose and enhance the radiation protection of patient in interventional radiology procedures. (author)

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

Directory of Open Access Journals (Sweden)

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.

An unusual complication of combined gonioscopy-assisted transluminal trabeculotomy and phacoemulsification: vision loss due to intracapsular hematoma.

Science.gov (United States)

Yalinbas, Duygu; Aktas, Zeynep; Hepsen, İbrahim; Dilekmen, Nilay

2017-09-23

To report two cases with an acute vision loss due to intracapsular hemorrhage (hematoma) after an uncomplicated gonioscopy-assisted transluminal trabeculotomy (GATT) combined with phacoemulsification surgery. Case report. Seventy-six-year-old male and 75-year-old female patients with cataract and pseudoexfoliative glaucoma (XFG) uncontrolled with maximum medical therapy both underwent GATT combined with phacoemulsification. Shortly after the surgery, intracapsular hematoma behind the intraocular lens (IOL) were noted in both patients. Hematoma cleared in both of them via IOL extraction-anterior vitrectomy and YAG-laser capsulotomy, respectively. Hematoma cleared in both patients without any surgical complications. Vision loss due to unclearing intracapsular hematoma might be an early complication of combined GATT and phacoemulsification surgery.

Experimental study of cooling performance of pneumatic synthetic jet with singular slot rectangular orifice

Science.gov (United States)

Yu, Roger Ho Zhen; Ismail, Mohd Azmi bin; Ramdan, Muhammad Iftishah; Mustaffa, Nur Musfirah binti

2017-03-01

Synthetic Jet generates turbulence flow in cooling the microelectronic devices. In this paper, the experiment investigation of the cooling performance of pneumatic synthetic jet with single slot rectangular orifices at low frequency motion is presented. The velocity profile at the end of the orifice was measured and used as characteristic performance of synthetic jet in the present study. Frequencies of synthetic jet and the compressed air pressure supplied to the pneumatic cylinder (1bar to 5bar) were the parameters of the flow measurement. The air velocity of the synthetic jet was measured by using anemometer air flow meter. The maximum air velocity was 0.5 m/s and it occurred at frequency motion of 8 Hz. The optimum compressed air supplied pressure of the synthetic jet study was 4 bar. The cooling performance of synthetic jet at several driven frequencies from 0 Hz to 8 Hz and heat dissipation between 2.5W and 9W were also investigate in the present study. The results showed that the Nusselt number increased and thermal resistance decreased with both frequency and Reynolds number. The lowest thermal resistance was 5.25°C/W and the highest Nusselt number was 13.39 at heat dissipation of 9W and driven frequency of 8Hz.

Long-term survival in children with atrioventricular septal defect and common atrioventricular valvar orifice in Sweden.

Science.gov (United States)

Frid, Christina; Björkhem, Gudrun; Jonzon, Anders; Sunnegårdh, Jan; Annerén, Göran; Lundell, Bo

2004-02-01

The survival for patients with atrioventricular septal defect has improved markedly over the last decades and, during the same period, the survival of children with Down's syndrome has also increased. The aim of our study was to investigate long-term survival in patients having atrioventricular septal defect with common valvar orifice, but without associated significant congenital heart defects, in the setting of Down's syndrome, comparing the findings to those in chromosomally normal children with the same malformation. In a population-based retrospective study, we scrutinised the medical records from 801 liveborn children with atrioventricular septal defect born in Sweden during the period 1973 through 1997. Data on gender, presence or absence of Down's syndrome, associated congenital heart defects, date of birth, operation and death were recorded and followed up until 2001. An isolated atrioventricular septal defect with common atrioventricular valvar orifice was present in 502 children, of whom 86% had Down's syndrome. We found a significant reduc tion over time in age at operation, and in postoperative mortality at 30 days, from 28 to 1%. Using a multiple logistic regression model, we found no significant differences in mortality between genders, nor between those with or without Down's syndrome. Early corrective surgery could not be identified as a significant independent factor for survival. The 5-year postoperative survival in patients with Down's syndrome increased from 65% over the period from 1973 through 1977, to about 90% in the period 1993 through 1997, and the same trend was observed in chromosomally normal patients. Survival in uncomplicated atrioventricular septal defect with common atrioventricular valvar orifice has greatly increased, and surgical correction is now equally successful in patients with Down's syndrome and chromosomally normal patients, and for both genders. Death in connection with surgery is no longer the major threat, and focus

The counter-current flooding limit in vertical tubes with and without orifices

International Nuclear Information System (INIS)

Tye, P.; Davidson, M.; Teyssedou, A.; Tapucu, A.; Matuszkiewicz, A.; Midvidy, W.

1993-01-01

For hypothetical loss of coolant accidents in nuclear reactors, rapid reflooding of the core is desirable. In CANDU reactors the cooling water is injected into the headers which are connected to the fuel channels by the feeder pipes. These pipes consist of vertical and horizontal runs; in some feeders, orifices and/or venturi flow meters are installed for flow adjustments and measurements respectively. For certain postulated accident scenarios, steam coming from the fuel channels and/or generated in the hot feeders may flow in the direction opposite to that of the cooling water thereby, creating a vertical or horizontal counter-current two-phase flow. Under these conditions, the rate at which cooling water can enter the fuel channels may be limited by the flooding phenomena. This phenomena is greatly affected by the geometry of the feeder pips, shape and number of fittings, and the flow area restrictions located in the feeders. In this paper the influence that orifice type flow area restrictions have on the counter-current flooding limit (CCFL) in a vertical tube is examined. air and water at close to atmospheric conditions are used as the working fluids. The data collected on the counter-current flooding limit in a vertical tube both with and without flow area restrictions is compared against some of the most commonly used correlations that are available in the open literature. Data on the two-phase counter-current pressure drop below the flooding point are also presented. 12 refs., 10 figs., 1 tab

Infrapopliteal Percutaneous Transluminal Balloon Angioplasty: Clinical Results and Influence Factors

Energy Technology Data Exchange (ETDEWEB)

Song, Jang Hyeon; Lee, Seung Jin; Jung, Hye Doo; Lim, Jae Hoon; Chang, Nam Kyu; Yim, Nam Yeol; Kim, Jae Kyu [Dept. of Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of); Lee, Keun Bae [Dept. of Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of)

2011-09-15

To assess the efficacy of percutaneous transluminal angioplasty (PTA) in patients with infrapopliteal arterial disease, and to determine the influencing factor for prognosis. A total of 55 patients (60 limbs) with infrapopliteal arterial stenosis or occlusion underwent PTA. Atherosclerotic risk factors, clinical symptoms, TransAtlantic Inter-Society Consensus (TASC) classification, and vascular wall calcification were evaluated before PTA. The number of patent infrapopliteal arteries was estimated, and the outcome was evaluated by symptom relief and limb salvage. Technical success was achieved in 53/60 limbs (88.3%) and 81/93 arteries (87.1%), TASC classification (p = 0.038) and vascular calcification (p = 0.002) influenced on technical failure. During follow-up, 26 of 55 limbs (47%) achieved symptom relief and 42/55 limbs (76%) underwent limb salvage. Non-diabetic patients (9/12, 75%) were superior to diabetic patients (17/43, 40%) in terms of symptom relief (p = 0.024). TASC classification and vascular wall calcification influenced on symptom relief and limb salvage. The number of patent infrapopliteal arteries after PTA influenced symptom relief (p < 0.001) and limb amputation (p = 0.003). PTA in patients with chronic critical limb ischemia is worthwhile as a primary treatment. The influence factors should be considered before PTA, and PTA should be performed in as many involved arteries as possible.

Infrapopliteal Percutaneous Transluminal Balloon Angioplasty: Clinical Results and Influence Factors

International Nuclear Information System (INIS)

Song, Jang Hyeon; Lee, Seung Jin; Jung, Hye Doo; Lim, Jae Hoon; Chang, Nam Kyu; Yim, Nam Yeol; Kim, Jae Kyu; Lee, Keun Bae

2011-01-01

To assess the efficacy of percutaneous transluminal angioplasty (PTA) in patients with infrapopliteal arterial disease, and to determine the influencing factor for prognosis. A total of 55 patients (60 limbs) with infrapopliteal arterial stenosis or occlusion underwent PTA. Atherosclerotic risk factors, clinical symptoms, TransAtlantic Inter-Society Consensus (TASC) classification, and vascular wall calcification were evaluated before PTA. The number of patent infrapopliteal arteries was estimated, and the outcome was evaluated by symptom relief and limb salvage. Technical success was achieved in 53/60 limbs (88.3%) and 81/93 arteries (87.1%), TASC classification (p = 0.038) and vascular calcification (p = 0.002) influenced on technical failure. During follow-up, 26 of 55 limbs (47%) achieved symptom relief and 42/55 limbs (76%) underwent limb salvage. Non-diabetic patients (9/12, 75%) were superior to diabetic patients (17/43, 40%) in terms of symptom relief (p = 0.024). TASC classification and vascular wall calcification influenced on symptom relief and limb salvage. The number of patent infrapopliteal arteries after PTA influenced symptom relief (p < 0.001) and limb amputation (p = 0.003). PTA in patients with chronic critical limb ischemia is worthwhile as a primary treatment. The influence factors should be considered before PTA, and PTA should be performed in as many involved arteries as possible.

The Influence of Swirl Brakes and a Tip Discharge Orifice on the Rotordynamic Forces Generated by Discharge-to-Suction Leakage Flows in Shrouded Centrifugal Pumps

Science.gov (United States)

Sivo, Joseph M.; Acosta, A. J.; Brennen, C. E.; Caughey, T. K.

1993-01-01

Recent experiments conducted in the Rotor Force Test Facility at the California Institute of Technology have examined the effects of a tip leakage restriction and swirl brakes on the rotordynamic forces due to leakage flows on an impeller undergoing a prescribed circular whirl. The experiments simulate the leakage flow conditions and geometry of the Alternate Turbopump Design (ATD) of the Space Shuttle High Pressure Oxygen Turbopump and are critical to evaluating the pump's rotordynamic instability problems. Previous experimental and analytical results have shown that discharge-to-suction leakage flows in the annulus of a shrouded centrifugal pump contribute substantially to the fluid induced rotordynamic forces. Also, previous experiments have shown that leakage inlet (pump discharge) swirl can increase the cross-coupled stiffness coefficient and hence increase the range of positive whirl for which the tangential force is destabilizing. In recent experimental work, the present authors demonstrated that when the swirl velocity within the leakage path is reduced by the introduction of ribs or swirl brakes, then a substantial decrease in both the destabilizing normal and tangential forces could be achieved. Motivation for the present research is that previous experiments have shown that restrictions such as wear rings or orifices at pump inlets affect the leakage forces. Recent pump designs such as the Space Shuttle Alternate Turbopump Design (ATD) utilize tip orifices at discharge for the purpose of establishing axial thrust balance. The ATD has experienced rotordynamic instability problems and one may surmise that these tip discharge orifices may also have an important effect on the normal and tangential forces in the plane of impeller rotation. The present study determines if such tip leakage restrictions contribute to undesirable rotordynamic forces. Additional motivation for the present study is that the widening of the leakage path annular clearance and the

Percutaneous transluminal mitral commissurotomy for rheumatic mitral stenosis in a 5-year-old child.

Science.gov (United States)

Ullah, Maad; Sultan, Mehboob; Akbar, Hajira; Sadiq, Nadeem

2012-06-01

We report a 5-year-old boy weighing 11 kg, with severe mitral valve stenosis of rheumatic aetiology, who underwent successful percutaneous transluminal mitral commissurotomy (PTMC) with valvuloplasty balloon. Postprocedural mean pressure gradient across the mitral valve decreased to 6 mmHg from an initially recorded value of 22 mmHg. In addition to symptomatic improvement, the mitral valvular area increased from 0.4 to 0.8 cm(2) without significant change in mitral regurgitation. At 1- and 3-month follow up, transthoracic echocardiography revealed further improvement with an increase in mitral valve area to 1.0 cm(2), a decrease in pulmonary arterial pressure, and a mean mitral valve pressure gradient of 8 mmHg with trivial mitral regurgitation. To best of our knowledge, this is the first successful PTMC procedure performed in the youngest and smallest ever reported child with rheumatic mitral stenosis (MS). We conclude that PTMC with valvuloplasty balloon could be a logical alternative to surgery in young patients with rheumatic MS.

Continuous synthesis of tert.-butyl peroxypivalate using a single channel micro reactor equipped with orifices as emulsification units

NARCIS (Netherlands)

Illg, T.; Hessel, V.; Löb, P.; Schouten, J.C.

2011-01-01

The two-step synthesis of tert-butyl peroxypivalate is performed in a single-channel microreactor. The first step, the deprotonation of tert-butyl hydroperoxide, is done in a simple mixer tube setup. The residence time section for the second reaction step is equipped with orifices for interfacial

Peroral endoscopic myotomy (POEM) for treating esophageal motility disorders

Science.gov (United States)

Wong, Ian

2017-01-01

Pneumatic dilatation and Heller myotomy have been thoroughly studied as the most viable treatment options for achalasia. The pendulum, however, is shifting to the minimally invasive approach. Since Inoue et al. published the experience of the first 17 cases of peroral endoscopic myotomy (POEM) in 2010, there have been at least 5,000 cases performed worldwide and the number is increasing exponentially. Experts across the globe have been extending the indications to various esophageal motility disorders, to patients of extremes of age, sigmoidal esophagus and re-operated patients. There are a few variations in technique across different centers in defining the gastroesophageal junction (GEJ) and adequacy of myotomy, the optimal length, site of myotomy and whether the full thickness of the muscle wall should be cut. Large case series demonstrated its promising efficacy & reasonable complication profile. Randomized controlled trial in comparison with the gold standard, Heller myotomy, is ongoing. The future application of submucosal tunnelling technique is thrilling with its extension in tumour resection, antropyloromyotomy and other natural orifice transluminal endoscopic surgery (NOTES). PMID:28616407

Endoscopic approaches to treatment of achalasia

Science.gov (United States)

Friedel, David; Modayil, Rani; Iqbal, Shahzad; Grendell, James H.

2013-01-01

Endoscopic therapy for achalasia is directed at disrupting or weakening the lower esophageal sphincter (LES). The two most commonly utilized endoscopic interventions are large balloon pneumatic dilation (PD) and botulinum toxin injection (BTI). These interventions have been extensively scrutinized and compared with each other as well as with surgical disruption (myotomy) of the LES. PD is generally more effective in improving dysphagia in achalasia than BTI, with the latter reserved for infirm older people, and PD may approach treatment results attained with myotomy. However, PD may need to be repeated. Small balloon dilation and endoscopic stent placement for achalasia have only been used in select centers. Per oral endoscopic myotomy is a newer endoscopic modality that will likely change the treatment paradigm for achalasia. It arose from the field of natural orifice transluminal endoscopic surgery and represents a scarless endoscopic approach to Heller myotomy. This is a technique that requires extensive training and preparation and thus there should be rigorous accreditation and monitoring of outcomes to ensure safety and efficacy. PMID:23503707

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

Science.gov (United States)

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.

Improved left ventricular function and perfusion at rest after successful transluminal coronary angioplasty

International Nuclear Information System (INIS)

Klepzig, H.; Kaltenbach, M.; Standke, R.; Maul, F.D.; Hoer, G.

1991-01-01

The purpose of this study was to evaluate left ventricular function and perfusion at rest before and after percutaneous transluminal coronary angioplasty. In consecutive 69 patients in whom coronary stenoses were dilated, the radionuclide left ventricular ejection fraction at rest increased significantly. In 26 of these patients, the ejection fraction increased by at least 4%. In these patients, exercise-induced ischemic ST depression had been more pronounced than in the others. 36 other patients underwent 201 Tl myocardial scintigraphy before and after angioplasty. Twelve patients in whom pre-PTCA images had revealed regions with irreversible 201 Tl uptake defects, showed normal 201 Tl distribution patterns on post-PTCA scintigrams. Post-exercise 201 Tl uptake (representing myocardial perfusion and metabolic activity) during pre-PTCA exercise stress tests was significantly lower in these cases. It is concluded that PTCA can improve left ventricular function and perfusion at rest. This improvement is most obvious in patients with pronounced exercise-induced myocardial ischemia as diagnosed by typical ST segment depression and reduced thallium uptake. (orig.) [de

Percutaneous transluminal angioplasty and stent placement for iliofemoral arterial atherosclerotic occlusive disease

International Nuclear Information System (INIS)

Zheng Yanbo; Jiang Wenjin; Liu Sheng; Song Xuepeng; Sheng Qirui

2006-01-01

Objectives: To assess the safety and efficacy of percutaneous transluminal angioplasty (PTA) and stent placement for the treatment of iliofemoral arterial atherosclerotic occlusive diseases. Methods From April 1999 to August 2004, 13 cases of iliofemoral arterial occlusions were recanalized with contact thrombolytic therapy combined with guide wire mechanical recanalization method, followed by angioplasty and stent placement. A total of 25 self-expanding Wallstents were deployed. All patients were followed up by means of duplex ultrasound, angiography, or both. Results: All 13 cases were successfully recanalized, with technical successful rate of 100%. Available follow-up for all patients from 8 months-5 years (mean 26.2 months) included one patient undergoing again with successful contact thrombolysis because of early thrombosis; another patient with recurrent symptoms at 19 month after operation undertaking surgical bypass because of later reocclusion; all of the rest stents showing patency by the end of the study. Conclusions: Contact thrombolysis combined with guide wire mechanical recanalization for iliofemoral arterial occlusion is safe and effective, whereas PTA and stent placement would have the nearly same efficacy for the disease with mild injury and low restenosis. (authors)

Disinfection of Escherichia coli bacteria using hybrid method of ozonation and hydrodynamic cavitation with orifice plate

Science.gov (United States)

Karamah, Eva F.; Ghaudenson, Rioneli; Amalia, Fitri; Bismo, Setijo

2017-11-01

This research aims to evaluate the performance of hybrid method of ozonation and hydrodynamic cavitation with orifice plate on E.coli bacteria disinfection. In this research, ozone dose, circulation flowrate, and disinfection method were varied. Ozone was produced by commercial ozonator with ozone dose of 64.83 mg/hour, 108.18 mg/hour, and 135.04 mg/hour. Meanwhile, hydrodynamic cavitation was generated by an orifice plate. The disinfection method compared in this research were: hydrodynamic cavitation, ozonation, and the combination of both. The best result on each method was achieved on the 60th minutes and with a circulation flowrate of 7 L/min. The hybrid method attained final concentration of 0 CFU/mL from the initial concentration of 2.10 × 105 CFU/mL. The ozonation method attained final concentration of 0 CFU/mL from the initial concentration of 1.32 × 105 CFU/mL. Cavitation method gives the least disinfection with final concentration of 5.20 × 104 CFU/mL from the initial concentration of 2.17 × 105 CFU/mL. In conclusion, hybrid method gives a faster and better disinfection of E.coli than each method on its own.

Burnout experiments in freon 12 using different types of orifices to simulate the core grids - comparision between measured and predicted burnout values

International Nuclear Information System (INIS)

Katsaounis, A.; Orlowski, R.; Fulfs, H.; Hofmann, K.; Ladeira, L.C.D.

1978-06-01

This paper will report on burnout experiments carried out in freon 12 mainly at steady state and further at mass flow or power transient conditions with annular test sections axially uniformly heating either the inside or both the inside and outside rod. The runs are performed without orifice and using three different types of orifices simulating the reactor spacer grid. An important influence of the flow restriction on burnout position and value is measured. Furthermore, the comparison between the burnout correlations W2, W3, BandW2 and GE and experimental results from the literature using simple test section geometries in water and freon 12 demonstrate, that the accuracy is more or less comparable for both fluids

Endovascular treatment with angioplasty or stenting versus endarterectomy in patients with carotid artery stenosis in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS): long-term follow-up of a randomised trial.

LENUS (Irish Health Repository)

Ederle, Jörg

2009-10-01

Endovascular treatment (angioplasty with or without stenting) is an alternative to carotid endarterectomy for carotid artery stenosis but there are scarce long-term efficacy data showing that it prevents stroke. We therefore report the long-term results of the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS).

Duplex-guided percutaneous transluminal angioplasty in iliac arterial occlusive disease.

Science.gov (United States)

Krasznai, A G; Sigterman, T A; Welten, R J; Heijboer, R; Sikkink, C J J M; van de Akker, L H J M; Bouwman, L H

2013-11-01

Chronic renal insufficiency (CRI) is a growing global problem. PTA can be performed without nephrotoxic contrast, utilizing Doppler-ultrasound (Duplex) guidance. Duplex-guided infra-inguinal interventions and access-related interventions have been reported. Duplex-guided iliac interventions have not been performed to any extent because of the anatomic location. In our study we evaluated the safety and efficacy of Duplex-guided percutaneous transluminal angioplasty (DuPTA) in iliac arteries. From June 2012 until February 2013, 31 patients (35 iliac lesions), underwent DuPTA. Indications ranged from Rutherford 3 to 5. Preoperative evaluation included Ankle Brachial Index (ABI), Duplex and MRA. Procedural success was defined as crossing the lesion with a guidewire and dilating or stenting the lesion. Clinical success was defined as 50% reduction in peak systolic velocity (PSV) or clinical improvement. PSV was evaluated after PTA, then at 2 weeks. Clinical results were assessed 2 weeks after the procedure. Procedural success was achieved in 94% of patients (33/35), all of whom also had clinical success. Post-procedural PSV reduction showed an average improvement of 63% (431 cm/s to 153 cm/s). Mean preoperative ABI was 0.72 and improved to 0.88 postoperatively. PTA using Duplex-guidance in significant iliac stenosis is a safe method with major advantages in patients at high risk for developing contrast-induced nephropathy. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Incidence of vascular complications in patients submitted to percutaneous transluminal coronary angioplasty by transradial and transfemoral arterial approach Incidencia de complicaciones vasculares en pacientes sometidos a angioplastía coronaria transluminal percutánea por vía arterial transradial y transfemoral Incidência de complicações vasculares em pacientes submetidos a angioplastia coronariana transluminal percutânea por via arterial transradial e transfemoral

Directory of Open Access Journals (Sweden)

Marinez Kellermann Armendaris

2008-03-01

Full Text Available OBJECTIVE: To describe the vascular complications of transradial and transfemoral artery punctures in patients submitted to percutaneous transluminal coronary angioplasty (PTCA. METHODS: Prospective cohort study including patients submitted to PTCA. An interview was performed and an instrument applied to collect risk factors/predictors of complications. After the procedure, a physical examination was performed, vital signs were measured and the puncture site was assessed. RESULTS: 199 patients were included, age 64±10 years. Complications found for the radial and femoral approach were respectively: ecchymosis (18.29%, (17.14%; bruising (17.66%, (14.27%; urinary retention (2.43%, (25.71%; loss of vessel permeability (8.53%, (0%. CONCLUSION: The complications found were considered minor or secondary, depending on the classification found in literature. A higher rate of vascular complications related to transradial artery punctures compared to the interventions performed by transfemoral approach.OBJETIVO: Describir complicaciones vasculares relacionadas a punciones arteriales transradial y transfemoral en pacientes sometidos a angioplastía coronaria transluminal percutánea (ACTP. MÉTODOS: Se trata de un estudio de cohorte prospectivo realizado con pacientes sometidos a ACTP. Se llevó a cabo una entrevista y aplicó un instrumento para obtener factores de riesgo/predictores. Fue realizado un examen físico, medición de signos vitales y se evaluó el lugar de punción. RESULTADOS: Fueron incluidos 199 pacientes, edad 64±10 años. Las complicaciones encontradas para vía radial y femoral respectivamente, fueron: esquimosis (18,29%, (17,14%; hematoma (17,66%, (14,27%; retención urinaria (2,43%, (25,71%; pérdida de permeabilidad de vaso (8,53%, (0%. CONCLUSIÓN: Las complicaciones fueron consideradas menores o secundarias conforme clasificación literaria. Existe una mayor incidencia de complicaciones vasculares relacionadas a punciones

Direct target NOTES: prospective applications for next generation robotic platforms.

Science.gov (United States)

Atallah, S; Hodges, A; Larach, S W

2018-05-01

A new era in surgical robotics has centered on alternative access to anatomic targets and next generation designs include flexible, single-port systems which follow circuitous rather than straight pathways. Such systems maintain a small footprint and could be utilized for specialized operations based on direct organ target natural orifice transluminal endoscopic surgery (NOTES), of which transanal total mesorectal excision (taTME) is an important derivative. During two sessions, four direct target NOTES operations were conducted on a cadaveric model using a flexible robotic system to demonstrate proof-of-concept of the application of a next generation robotic system to specific types of NOTES operations, all of which required removal of a direct target organ through natural orifice access. These four operations were (a) robotic taTME, (b) robotic transvaginal hysterectomy in conjunction with (c) robotic transvaginal salpingo-oophorectomy, and in an ex vivo model, (d) trans-cecal appendectomy. Feasibility was demonstrated in all cases using the Flex ® Robotic System with Colorectal Drive. During taTME, the platform excursion was 17 cm along a non-linear path; operative time was 57 min for the transanal portion of the dissection. Robotic transvaginal hysterectomy was successfully completed in 78 min with transvaginal extraction of the uterus, although laparoscopic assistance was required. Robotic transvaginal unilateral salpingo-oophorectomy with transvaginal extraction of the ovary and fallopian tube was performed without laparoscopic assistance in 13.5 min. In an ex vivo model, a robotic trans-cecal appendectomy was also successfully performed for the purpose of demonstrating proof-of-concept only; this was completed in 24 min. A flexible robotic system has the potential to access anatomy along circuitous paths, making it a suitable platform for direct target NOTES. The conceptual operations posed could be considered suitable for next generation robotics once

FORMULATION DEVELOPMENT OF MUCOADHESIVE MICROCAPSULES OF METFORMIN HYDROCHLORIDE USING NATURAL AND SYNTHETIC POLYMERS AND IN VITRO CHARACTERIZATION

OpenAIRE

Yellanki Shiva Kumar; Deb Sambit kumar; Goranti Sharada; Nerella Naveen kumar

2010-01-01

The objective of this work was to develop optimized and systematically evaluate performances of mucoadhesive microcapsules of antihyperglycemic agent drug Metformin. Alginate microcapsules coated with mucoadhesive natural or synthetic polymers were prepared by Orifice-Ionic Gelation technique utilizing calcium chloride as a cross linking agent. The effect of type (natural or synthetic) and concentration of coating polymers and concentration of alginate on formulation was investigated. Prepare...

Transluminal Angioplasty of Peroneal Artery Branches in Diabetics: Initial Technical Experience

International Nuclear Information System (INIS)

Graziani, Lanfroi; Silvestro, Antonio; Monge, Luca; Boffano, Gian Mario; Kokaly, Francesco; Casadidio, Ilaria; Giannini, Francesco

2008-01-01

The present study aimed to report the technical feasibility of percutaneous transluminal angioplasty (PTA) of obstructed or insufficient collateral branches (anterior and posterior perforating branches) from distal peroneal to foot arteries in diabetic patients with chronic critical limb ischemia (CLI) and chronic noncrossable occlusion of the anterior and posterior tibial arteries. Twenty-four diabetic CLI patients (age, 67 ± 8 years; 87% males) undergoing collateral PTA were included. Baseline clinical angiographic and follow-up data were retrospectively reviewed. Collateral PTA was associated with a concomitant PTA of other sites in 21 (83%) cases. In 15 cases the treated collateral linked the peroneal with the plantaris communis; in 9 cases, the peroneal with the dorsalis pedis. Angiographic results of collateral PTA were good in 13 cases (<30% residual stenosis), whereas the result was considered moderate (30%-49% residual stenosis) in the remaining cases. Neither perforation nor acute occlusion of the treated collaterals or other relevant complications were observed. Mean follow-up was 32 ± 17 months. Major amputation was necessary for two (8.3%) patients. Cumulative limb salvage rates at 2 and 4 years were 96% and 87%, respectively. In conclusion, this initial experience shows that PTA of the collateral branches from distal peroneal to foot arteries is a feasible technique. Future studies are required to define the clinical role of this novel approach

Characterization of Gatewell Orifice Lighting at the Bonneville Dam Second Powerhouse and Compendium of Research on Light Guidance with Juvenile Salmonids

Energy Technology Data Exchange (ETDEWEB)

Mueller, Robert P.; Simmons, Mary Ann

2007-12-29

The goal of the study described in this report is to provide U.S. Army Corps of Engineers (USACE) biologists and engineers with general design guidelines for using artificial lighting to enhance the passage of juvenile salmonids into the collection channel at the Bonneville Dam second powerhouse (B2). During fall 2007, Pacific Northwest National Laboratory (PNNL) researchers measured light levels in the field at one powerhouse orifice through which fish must pass to reach the collection channel. Two light types were evaluated—light-emitting diode (LED) lights and halogen spot lights. Additional measurements with mercury lamps were made at the PNNL Aquatic Research Laboratory to determine baseline intensity of the current lighting. A separate chapter synthesizes the relevant literature related to light and fish guidance for both field and laboratory studies. PNNL will also review the Corps plans for existing lighting protocol at all of the Portland District projects and help develop a uniform lighting scheme which could be implemented. The specific objectives for this study are to 1. Create a synthesis report of existing lighting data for juvenile salmonid attraction and deterrence and how the data are used at fish bypass facilities. 2. Evaluate current B2 orifice lighting conditions with both LED and halogen sources. 3. Make recommendations as to what lighting intensity, source, and configuration would improve passage at the B2 orifices. 4. Review USACE plans for retrofit of existing systems (to be assessed at a later date).

A mathematical model for erosion-corrosion downstream of an orifice

International Nuclear Information System (INIS)

Thomas, R.M.

1989-08-01

In certain types of nuclear plant, the internal surfaces of the steel high-pressure boiler tubes become covered with magnetite. This normal growth of protective magnetite may, in unfavourable circumstances, be replaced by rapid attack on the tube wall. Particularly at risk are the regions downstream of the orifice plates commonly fitted near the boiler inlet. An attempt is made to construct a mathematical model for this erosion-corrosion which is considerably more complete than those available hitherto. A systematic synthesis is developed of the various aspects of the phenomenon, namely the mechanism of the topotactic oxidation at the interface between magnetite and metal, the kinetics of the electrode reactions at the magnetite/solution interface, the thermodynamics of magnetite solubility and the calculation of mass transfer in solution. With one choice of parameters and some simplification, the treatment reduces to the original theory of Bignold. (author)

CFD study of a simple orifice pulse tube cooler

Science.gov (United States)

Zhang, X. B.; Qiu, L. M.; Gan, Z. H.; He, Y. L.

2007-05-01

Pulse tube cooler (PTC) has the advantages of long-life and low vibration over the conventional cryocoolers, such as G-M and Stirling coolers because of the absence of moving parts in low temperature. This paper performs a two-dimensional axis-symmetric computational fluid dynamic (CFD) simulation of a GM-type simple orifice PTC (OPTC). The detailed modeling process and the general results such as the phase difference between velocity and pressure at cold end, the temperature profiles along the wall as well as the temperature oscillations at cold end with different heat loads are presented. Emphases are put on analyzing the complicated phenomena of multi-dimensional flow and heat transfer in the pulse tube under conditions of oscillating pressure. Swirling flow pattern in the pulse tube is observed and the mechanism of formation is analyzed in details, which is further validated by modeling a basic PTC. The swirl causes undesirable mixing in the thermally stratified fluid and is partially responsible for the poor overall performance of the cooler, such as unsteady cold-end temperature.

Usefulness of percutaneous transluminal coronary angioplasty in silent myocardial ischemia

International Nuclear Information System (INIS)

Hou, Mami

1996-01-01

The usefulness of percutaneous transluminal coronary angioplasty (PTCA) was assessed in patients with exercise-induced asymptomatic myocardial ischemia (silent ischemia) and compared with exercise-induced symptomatic myocardial ischemia (symptomatic ischemia). Patients with single vessel coronary artery disease (51 with angina pectoris, 40 with old myocardial infarction) and evidence of stress-induced ischemia on thallium-201 single photon emission computed tomography (SPECT) underwent successful PTCA. Thirty-seven percent of angina patients and 60% of infarction patients showed asymptomatic exercise-induced ischemia. There was no significant difference in population characteristics between silent and symptomatic patients. Patients with silent angina had significantly higher percentage thallium uptake and washout rate than symptomatic patients. After PTCA, both percentage diameter stenosis and percentage thallium uptake were improved in all patients with angina irrespective of the presence or absence of symptoms. There were no significant differences in percentage thallium uptake and washout rate between patients with silent and symptomatic infarction. After PTCA, percentage diameter stenosis, percentage thallium uptake, and washout rate improved in all infarction patients irrespective of the symptoms. Zero percent of silent angina patients, 12% of symptomatic angina patients, 12% of silent infarction patients, 19% of symptomatic infarction patients had cardiac events during about 4.5 years after PTCA. The incidence of cardiac events did not significantly differ in any patient group. PTCA improved myocardial perfusion in all patients, and the incidence of cardiac events did not differ between the silent and symptomatic groups. Revascularization with PTCA is suitable for patients with silent as well as symptomatic ischemia. (author)

Retroperitoneal abscess after transanal minimally invasive surgery: case report and review of literature

Directory of Open Access Journals (Sweden)

Aaron Raney

2017-10-01

Full Text Available Abscesses are a rare complication of transanal minimally invasive surgery and transanal endoscopic micro surgery. Reported cases have been in the rectal and pre-sacral areas and have been managed with either antibiotics alone or in conjunction with laparotomy and diverting colostomy. We report a case of a large retroperitoneal abscess following a Transanal minimally invasive surgery full thickness rectal polyp excision. The patient was successfully managed conservatively with antibiotics and a percutaneous drain. Retroperitoneal infection should be included in a differential diagnosis following a Transanal minimally invasive surgery procedure as the presentation can be insidious and timely intervention is needed to prevent further morbidity. Resumo: Os abscessos são uma complicação rara da cirurgia de ressecção transanal minimamente invasiva (TAMIS e da micro cirurgia endoscópica transanal (TEMS. Os casos notificados foram nas áreas rectal e pré-sacral e foram administrados com antibióticos isoladamente ou em conjunto com laparotomia e desvio de colostomia. Relatamos um caso de grande abscesso retroperitoneal após uma excisão de pólipo retal de espessura total TAMIS. O paciente foi tratado com sucesso com a administração de antibióticos e drenagem percutânea. Para prevenir mais morbidade é necessária incluir a infecção retroperitoneal no diagnostico diferencial após um procedimento TAMIS onde a apresentação pode ser insidiosa e a intervenção atempada. Keywords: Colorectal surgery, Transanal minimally invasive surgery (TAMIS, Retroperitoneal abscess, Natural orifice transluminal endoscopic surgery (NOTES, Single-site laparoscopic surgery (SILS, Surgical oncology, Palavras-chave: Cirurgia colorretal, Cirurgia de ressecção transanal minimamente invasiva (TAMIS, Abscesso retroperitoneal, Cirurgia endoscópica transluminal de orifício natural (NOTES, Cirurgia laparoscópica de único local (SILS, Oncologia cirúrgica

Numerical simulation of trans-critical carbon dioxide (R744) flow through short tube orifices

Energy Technology Data Exchange (ETDEWEB)

Garcia-Valladares, O. [Centro de Investigacion en Energia de la Universidad Nacional Autonoma de Mexico, Privada Xochicalco S/N, Apdo. Postal 34, 62580 Temixco, Morelos (Mexico)

2006-02-01

A detailed one-dimensional numerical simulation of the fluid-dynamic behaviour of short tube orifices expansion devices working with trans-critical carbon dioxide (CO{sub 2} or R744) has been developed. The discretized governing equations are coupled using an implicit step by step method. A special treatment has been implemented in order to consider transitions (subcooled liquid region and equilibrium two-phase region). The numerical model allows analysis of aspects such as geometry, different working conditions, critical or non-critical flow conditions, etc. Comparison of the numerical simulation with experimental data presented in the technical literature will be shown in the present article. (author)

Randomized trial of Legflow® paclitaxel eluting balloon and stenting versus standard percutaneous transluminal angioplasty and stenting for the treatment of intermediate and long lesions of the superficial femoral artery (RAPID trial): Study protocol for a randomized controlled trial

NARCIS (Netherlands)

A. Karimi; S.W. de Boer (Sanne W.); D.A.F. Van Den Heuvel; B. Fioole (Bram); D. Vroegindeweij (Dammis); J.M.M. Heyligers (Jan); P.N.M. Lohle (Paul N.M.); O.E. Elgersma (Otto E.); R.P.T. Nolthenius (Rudolf ); J.A. Vos (Jan Albert); J.-P.P.M. de Vries (Jean-Paul)

2013-01-01

textabstractBackground: Restenosis after percutaneous transluminal angioplasty (PTA) of the superficial femoral artery (SFA) may occur in 45% of patients at 2 years follow-up. Paclitaxel-coated balloons have been found to reduce neointimal hyperplasia, and thus reduce restenosis. Recently, the

Long-term risk of carotid restenosis in patients randomly assigned to endovascular treatment or endarterectomy in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS): long-term follow-up of a randomised trial.

LENUS (Irish Health Repository)

Bonati, Leo H

2009-10-01

In the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), early recurrent carotid stenosis was more common in patients assigned to endovascular treatment than it was in patients assigned to endarterectomy (CEA), raising concerns about the long-term effectiveness of endovascular treatment. We aimed to investigate the long-term risks of restenosis in patients included in CAVATAS.

A Miniature Robot for Retraction Tasks under Vision Assistance in Minimally Invasive Surgery

Directory of Open Access Journals (Sweden)

Giuseppe Tortora

2014-03-01

Full Text Available Minimally Invasive Surgery (MIS is one of the main aims of modern medicine. It enables surgery to be performed with a lower number and severity of incisions. Medical robots have been developed worldwide to offer a robotic alternative to traditional medical procedures. New approaches aimed at a substantial decrease of visible scars have been explored, such as Natural Orifice Transluminal Endoscopic Surgery (NOTES. Simple surgical tasks such as the retraction of an organ can be a challenge when performed from narrow access ports. For this reason, there is a continuous need to develop new robotic tools for performing dedicated tasks. This article illustrates the design and testing of a new robotic tool for retraction tasks under vision assistance for NOTES. The retraction robots integrate brushless motors to enable additional degrees of freedom to that provided by magnetic anchoring, thus improving the dexterity of the overall platform. The retraction robot can be easily controlled to reach the target organ and apply a retraction force of up to 1.53 N. Additional degrees of freedom can be used for smooth manipulation and grasping of the organ.

Estimation of the measurement error of eccentrically installed orifice plates

Energy Technology Data Exchange (ETDEWEB)

Barton, Neil; Hodgkinson, Edwin; Reader-Harris, Michael

2005-07-01

The presentation discusses methods for simulation and estimation of flow measurement errors. The main conclusions are: Computational Fluid Dynamics (CFD) simulation methods and published test measurements have been used to estimate the error of a metering system over a period when its orifice plates were eccentric and when leaking O-rings allowed some gas to bypass the meter. It was found that plate eccentricity effects would result in errors of between -2% and -3% for individual meters. Validation against test data suggests that these estimates of error should be within 1% of the actual error, but it is unclear whether the simulations over-estimate or under-estimate the error. Simulations were also run to assess how leakage at the periphery affects the metering error. Various alternative leakage scenarios were modelled and it was found that the leakage rate has an effect on the error, but that the leakage distribution does not. Correction factors, based on the CFD results, were then used to predict the system's mis-measurement over a three-year period (tk)

Randomized trial of Legflow((R)) paclitaxel eluting balloon and stenting versus standard percutaneous transluminal angioplasty and stenting for the treatment of intermediate and long lesions of the superficial femoral artery (RAPID trial): study protocol for a randomized controlled trial

NARCIS (Netherlands)

Karimi, A.; Boer, S.W. de; Heuvel, D.A. Van Den; Fioole, B.; Vroegindeweij, D.; Heyligers, J.M.M; Lohle, P.N.; Elgersma, O.; Nolthenius, R.P.T.; Vos, J.A.; Vries, J.P. de

2013-01-01

BACKGROUND: Restenosis after percutaneous transluminal angioplasty (PTA) of the superficial femoral artery (SFA) may occur in 45% of patients at 2 years follow-up. Paclitaxel-coated balloons have been found to reduce neointimal hyperplasia, and thus reduce restenosis. Recently, the Legflow((R))

Quantitative characterization of near-field fuel sprays by multi-orifice direct injection using ultrafast x-tomography technique

International Nuclear Information System (INIS)

Liu, X.; Im, K.S.; Wang, Y.; Wang, J.; Hung, D.L.S.; Winkelman, J.R.; Tate, M.W.; Ercan, A.; Koerner, L.J.; Caswell, T.; Chamberlain, D.; Schuette, D.R.; Philipp, H.; Smilgies, D.M.; Gruner, S.M.

2006-01-01

A low-pressure direct injection fuel system for spark ignition direct injection engines has been developed, in which a high-turbulence nozzle technology was employed to achieve fine fuel droplet size at a low injection pressure around 2 MPa. It is particularly important to study spray characteristics in the near-nozzle region due to the immediate liquid breakup at the nozzle exit. By using an ultrafast x-ray area detector and intense synchrotron x-ray beams, the interior structure and dynamics of the direct injection gasoline sprays from a multi-orifice turbulence-assisted nozzle were elucidated for the first time in a highly quantitative manner with μs-temporal resolution. Revealed by a newly developed, ultrafast computed x-microtomography technique, many detailed features associated with the transient liquid flows are readily observable in the reconstructed spray. Furthermore, an accurate 3-dimensional fuel density distribution, in the form of fuel volume fraction, was obtained by the time-resolved computed tomography. The time-dependent fuel density distribution revealed that the fuel jet is well broken up immediately at the nozzle exits. These results not only reveal the near-field characteristics of the partial atomized fuel sprays with unprecedented detail, but also facilitate the development of an advanced multi-orifice direct injector. This ultrafast tomography capability also will facilitate the realistic computational fluid dynamic simulations in highly transient and multiphase fuel spray systems.

Angiographic Characteristics of Symptomatic Recurrent Disease After Infrainguinal Percutaneous Transluminal Angioplasty

International Nuclear Information System (INIS)

Soeder, Heini K.; Manninen, Hannu I.; Matsi, Pekka J.

1999-01-01

Purpose: To evaluate the angiographic patterns of clinically manifest recurrent disease after infrainguinal percutaneous transluminal angioplasty (PTA) of stenoses and total occlusions. Methods: Among 326 infrainguinal PTAs on 263 consecutive patients, selective angiography was performed on 61 limbs of 52 patients 1-60 months after the primary intervention because of clinically suspected recurrent disease. Lesion-specific and patient-related factors were analyzed for 75 angiographically confirmed recurrent lesions in 57 limbs of 48 patients. Results: Recurrent disease was more frequently a stenosis when the original target lesion was a stenosis (92%, 44/48) than when the original lesion was a total occlusion (59%, 16/27; p < 0.001). When the original target lesion was a stenosis, the total length of the recurrent disease was longer than that of the original lesion [3.9 ± 3.9 cm (mean ± standard deviation) vs 2.8 ± 2.7 cm; p= 0.03], while in the subgroup of original total occlusions the length of the recurrent lesion was shorter than that of the original occlusion (7.1 ± 5.0 cm vs 9.9 ± 6.9 cm; p0.02). Half the restenoses (22/44) extended beyond one or both ends of the original stenosis and 38% (6/16) of the reocclusions extended beyond the distal end of the original occlusion. Conclusions: The type of recurrent disease depends on the original lesion type and the restenotic lesion frequently extends beyond one or both ends of the original target lesion

[Synchronized anterograde perfusion during percutaneous transluminal coronary angioplasty: preliminary clinical study].

Science.gov (United States)

Farcot, J C; Berland, J; Derumeaux, G; Letac, B; Bourdarias, J P

1995-03-01

A new circulatory system, "physiologic anteroperfusion system", has been developed and tested in 6 patients with significant proximal coronary artery stenosis. Prolonged and safe balloon inflation was possible without any ischemic signs. The system consists of an electronic cardiac synchroperfusor which, by activating a pulsatile unit, permits increased diastolic anteroperfusion of autologous blood under physiologic pressure through low-profile standard angioplasty catheters. This study reports the results obtained in 6 patients during proximal prolonged percutaneous transluminal coronary angioplasty. Four men and two women suffering from severe exertional angina pectoris, with normal resting left ventricular function, no collaterals and excellent apical two-dimensional four-chamber echocardiographic views were studied. After a 90 +/- 10 seconds of control occlusion under continuous monitoring of hemodynamics, electrocardiograms (3 to 4 leads), two-dimensional echo and chest pain grading, a second balloon inflation protected by the physiologic anteroperfusion system at a flow rate of 44 +/- 12 ml/min was performed for fifteen minutes. The ischemic signs present in the myocardium depending on the occluded artery were totally abolished during prolonged inflation protected by physiologic anteroperfusion system. All the patients were successfully dilated and were discharged from hospital the following morning without cardiac enzyme elevation or signs of central or peripheral hemolysis. Conclusion, in 6 patients with severe proximal coronary artery stenosis, safe prolonged proximal angioplasty without signs of ischemia was performed using a new simple physiologic anteroperfusion system, which allows active diastolic flow-pressure controlled autologous arterial blood perfusion, through standard low profile catheters.

Pressure drop calculation using a one-dimensional mathematical model for two-phase flow through an orifice

DEFF Research Database (Denmark)

Petkov, K.P.; Puton, M; Madsen, Søren Peder

2014-01-01

are accounted for through both friction and acceleration as in a conventional formulation. However, in this analysis the acceleration term is both attributed geometrical effects through the area change and fluid dynamic effects through the expansion of the two-phase flow. The comparison of numerical...... is a one dimensional formulation in space and the equations incorporates the change in tubes and orifice diameter as formulated in (S. Madsen et.al., Dynamic Modeling of Phase Crossings in Two-Phase Flow, Communications in Computational Physics 12 (4), 1129-1147). The pressure changes in the flow...

Pemodelan Dan Analisis Pengaruh Variasi Oli dan Diameter Orifice terhadap Gaya Redam Shock Absorber Dan Respon Dinamis Sepeda Motor Yamaha Jupiter Z 2008

Directory of Open Access Journals (Sweden)

Newanda Asa Wahid

2017-03-01

Full Text Available Sepeda motor merupakan moda transportasi yang paling banyak diminati oleh masyarakat Indonesia. Dalam hal kenyamanan, maka komponen sepeda motor yang berperan penting adalah sistem suspensi. Sistem suspensi berfungsi menyerap getaran berlebih akibat profil permukaan jalan, sehingga meningkatkan kenyamanan dan keamanan. Oleh karena itu, perlu dilakukan penelitian untuk mendapatkan sistem suspensi yang terbaik. Dalam tugas akhir ini dilakukan pemodelan dan analisis pengaruh perubahan parameter sistem suspensi sepeda motor Yamaha Jupiter Z 2008 khususnya pada komponen monotube hydraulic shock absorber yang didasarkan pada pemodelan setengah kendaraan. Parameter yang divariasikan adalah tipe oli dan diameter orifice, dimana terdapat 5 macam tipe oli dengan rentang nilai massa jenis (ρ sebesar 845 – 874 kg/m3, dan viskositas (ν sebesar 11,3 – 46 mm2/s, sementara untuk diameter orifice yaitu saat kompresi (Docomp sebesar 1,2 – 1,5 mm, saat ekspansi (Doexp sebesar 0,8 – 1 mm. Input yang digunakan pada simulasi adalah input sinusoidal dan input bump modified. Dari penelitian ini didapatkan hasil bahwa sistem suspensi modifikasi monotube hydraulic shock absorber yang menghasilkan gaya redam optimal memiliki nilai parameter viskositas kinematis oli 46 mm2/s, massa jenis oli 845 kg/m3, diameter orifice kompresi 0,00135 m, dan diameter orifice ekspansi 0,0009 m. Nilai gaya redam optimal yang dihasilkan sistem suspensi modifikasi adalah sebesar 1171,3 N, lebih tinggi hingga 546,44 N dibandingkan dengan gaya redam sistem supensi asli yang bernilai 624,86 N pada frekuensi 2 Hz. Pada sistem setengah kendaraan motor dengan penggunaan sistem suspensi asli maupun modifikasi, untuk input bump, respon kendaraan dan penumpang mencapai steady state kurang dari 2 detik dan 5 detik, sedangkan untuk input sinusoidal responnya mencapai steady state kurang dari 2 detik dan 3 detik. Penggunaan suspensi asli maupun modifikasi menghasilkan nilai perpindahan RMS yang

Percutaneous transluminal angioplasty with stenting for treatment of superior vena cava obstructive syndrome

International Nuclear Information System (INIS)

Chen Shiwei; Qiao Delin

2004-01-01

Objective: To evaluate the clinical value of percutaneous transluminal angioplasty with stenting (PTAS) for the treatment of superior vana cava obstructive syndrome (SVCOS). Methods: 15 cases of SVCOS including 10 cases of lung cancer with mediastinal lymphatic metastasis, 3 cases as malignant lymphoma and 2 cases of esophageal cancer with mediastinal lymphadenopathy, were undergone right subclavian vein or elbow vein catheterization for pressure measurement and DSA imaging of SVC with displaying the obstructive characteristics. A self-expanding stent was then implanted through right femoral vein catheterization. Results: 15 cases were all successfully under-taken angioplasty and stenting, except 1 case with a long stricture over 10 cm requiring 2 stents. After successful stent placement, DSA revealed smooth flow of contrast with almost normal diameter of SVC lumen, together with disappearance or relief of SVCOS. The SVC pressure decreased from 30.5±2.3 cmH 2 O down to 8.8 ± 1.5 cmH 2 O after recanalization, with a significant difference in statistics (P<0.01). All the patients were followed up for 6 months and obstructive symptom did not reappear except one case complicated with thrombosis which was treated by regional thrombolysis and balloon dilation leading to obviously improved symptom. Conclusion: PTAS for the treatment of SVCOS is effective, safe, simple and of less complications. (authors)

Selection of patients with infrainguinal arterial occlusive disease for percutaneous transluminal angioplasty with duplex scanning

International Nuclear Information System (INIS)

Bostroem Ardin, A.; Hellberg, A.; Ljungman, C.; Logason, K.; Karacagil, S.; Loefberg, A.M.; Andren, B.

2002-01-01

Aim: To evaluate the role of duplex scanning in the selection of patients with infrainguinal arterial occlusive disease for percutaneous transluminal angioplasty (PTA). Material and Methods: From January 1995 through May 2000, 702 patients (952 limbs), with chronic lower extremity ischemia due to infrainguinal atherosclerotic disease diagnosed by duplex scanning, were retrospectively studied. Diagnostic angiography (130 limbs) or infrainguinal PTA (108 limbs) was performed in 238 limbs. Two investigators retrospectively analyzed the duplex examinations and angiographies in a blinded manner and used similar criteria for the interpretation of lesions suitable or not suitable for PTA. Results: The superficial femoral, popliteal and crural artery lesions were correctly selected for PTA in 85%, 66% and 32%, respectively. The accuracy, sensitivity, specificity, negative predictive value and positive predictive value of duplex scanning to appropriately categorize femoropopliteal lesions as suitable or unsuitable for PTA were 89%, 83%, 92%, 94% and 78%, respectively. The accuracy of duplex scanning for predicting the performance of infrainguinal PTA was 83%. Conclusion: Duplex scanning has an important impact on the selection of treatment modalities in limbs with infrainguinal arterial occlusive disease. Femoropopliteal lesions can be reliably selected to PTA according to duplex scan findings

[Meta-analysis of percutaneous transluminal atherectomy in the treatment for in-stent restenosis of lower extremity peripheral artery disease].

Science.gov (United States)

Li, Weihao; Zhang, Tao; Liu, Yunfeng; Zhang, Yongbao; Li, Qingle; Zhang, Xiaoming; Shen, Chenyang

2015-11-24

To evaluate the clinical safety and efficacy of percutaneous transluminal atherectomy for in-stent restenosis (ISR) in patients with low extremity peripheral arterial diseases (PAD). PubMed, Elsevier, EBSCO, Spring databases and Cochrane Library were searched for relevant articles. Based on the different mechanisms of atherectomy, the patients were divided into mechanic atherectomy group and laser atherectomy group. The safety end points included the rate of distal embolism and severe arterial wall injuries. And the efficacy end points included primary patency rate and freedom from target vessel revascularization (TVR-free) 6 months and 12 months after surgery. A total of 9 studies and 620 patients (published between 2006 and 2014) were accepted. The rate of distal embolism was 4.2% (95% confidence interval (CI): 1.7%-6.7%), while that of severe arterial wall injuries was 1.9% (95%CI: 0.9%-3.0%), respectively. Laser atherectomy was responsible for more distal embolism (6.8%) compared to mechanic atherectomy (2.0%), which was significantly different (Q=21.66, P=0.010). At 6-month follow-up, primary patency rate and rate of TVR-free were 63.0% (95% CI: 55.5%-70.6%) and 80.4% (95% CI: 70.5%-90.3%), while at 12-month follow-up were 43.5% (95%CI: 32.2%-54.9%) and 58.0% (95% CI: 52.1%-63.9%), respectively. The free-TVR rate at 6 months follow-up in mechanical atherectomy group was 77.9%, and was inferior to that in laser atherectomy group (80.8%, Q=13.49, P=0.009). Published bias was discovered at the analysis of 12-month TVR-free rate by means of Begg Test (P=0.039). Meta analysis concerned about the 3 randomized controlled trials demonstrated that there was no significant improvement using atherectomy for ISR comparing to standard balloon at 6-month TVR-free rate (OR=1.34, 95% CI: 0.86-2.07, P=0.196). To treat ISR lesion in lower extremities, laser atherectomy has a lower free-TVR rate in the middle term follow-up.A higher rate of distal embolism is noted though. On

Patients' feelings and experiences during and after peripheral percutaneous transluminal angioplasty

International Nuclear Information System (INIS)

Lundén, Maud; Lundgren, Solveig M.; Persson, Lars-Olof; Lepp, Margret

2015-01-01

Background: Peripheral Arterial Disease (PAD) often caused by atherosclerosis is a major health care issue worldwide. Percutaneous Transluminal Angioplasty (PTA) on the lower limb is a common procedure used to enhance peripheral circulation. With an increasing number of individuals acquiring peripheral PTA treatment and with an increased focus on patient centred care, there is a need to find out more about patients' feelings and thoughts of undergoing PTA. Aim: The aim was to identify patients who are predominantly anxious or calm during and after peripheral PTA and to explore reasons for these feelings. Method: The study includes 51 patients who received PTA treatment in western Sweden. Findings: Seventy-eight percent of the patients rated themselves as calm after the PTA. The analysed interviews resulted in two themes: reasons for feelings of calmness and reasons for feelings of anxiety. Conclusion: In order to feel calm during and after the PTA, information given prior to the PTA needs to be comprehensive and consistent with the actual situation at the angiography suite. The dialogue with the physician and the radiographers was considered valuable, as was the ability to follow the procedure on the image screen. It is concluded that a thorough dialogue with the physician in a calm setting after the PTA is important for the patients' ability to foresee and plan for the future. Moreover, there is a need to find ways to improve analgesic routines regarding assessment and evaluation in connection with PTA treatment as pain is shown to increase anxiety

Transvaginal organ extraction: potential for broad clinical application.

Science.gov (United States)

Jacobsen, Garth R; Barajas-Gamboa, Juan S; Coker, Alisa M; Cheverie, Joslin; Macias, C Aitor; Sandler, Bryan J; Talamini, Mark A; Horgan, Santiago

2014-02-01

Natural orifice transluminal endoscopic surgery procedures have evolved over the past few years. A transvaginal approach is a promising alternative for intraperitoneal procedures. Our objective was to evaluate the safety and feasibility of transvaginal organ extraction. This institutional review board-approved protocol involved retrospective review of an ongoing prospective study. Female subjects who presented to our hospital for elective cholecystectomy, appendectomy, or sleeve gastrectomy were offered participation in the study. Eligible patients met the following criteria: age between 18 and 75, diagnosis of gallbladder disease, acute appendicitis, or morbid obesity who desired surgical treatment. A hybrid transvaginal natural orifice approach was used in this series. Thirty-four women underwent transvaginal organ extraction between September 2007 and January 2012. The mean age was 40 ± 12.1 years (range 23-63 years). The mean body mass index was 27 ± 6.4 kg/m(2) (range 16-43 kg/m(2)). All patients had an American Society of Anesthesiologists classification of two or below. The mean operative time for cholecystectomy, appendectomy, and sleeve gastrectomy was 90, 71, and 135 min, respectively. There were no conversions to open operation and no intraoperative complications. The mean hospital stay was 2 days for all cases. Patients were followed for a mean of 24 months (range 1-61 months). There were two pregnancies and two successful vaginal deliveries. Six patients (18 %) had minor complaints of spotting or heavy menses in the immediate postoperative period that resolved with conservative measures. There were no abdominal wall complications. There were no long-term complications and no mortalities. This initial experience suggests that this surgical approach is safe, does not increase length of stay, and has no long-term vaginal complications. Given this attractive profile, a transvaginal approach may prove to be a superior mode of organ extraction

Educational and training aspects of new surgical techniques: experience with the endoscopic–laparoscopic interdisciplinary training entity (ELITE) model in training for a natural orifice translumenal endoscopic surgery (NOTES) approach to appendectomy.

Science.gov (United States)

Gillen, Sonja; Gröne, Jörn; Knödgen, Fritz; Wolf, Petra; Meyer, Michael; Friess, Helmut; Buhr, Heinz-Johannes; Ritz, Jörg-Peter; Feussner, Hubertus; Lehmann, Kai S

2012-08-01

Natural orifice translumenal endoscopic surgery (NOTES) is a new surgical concept that requires training before it is introduced into clinical practice. The endoscopic–laparoscopic interdisciplinary training entity (ELITE) is a training model for NOTES interventions. The latest research has concentrated on new materials for organs with realistic optical and haptic characteristics and the possibility of high-frequency dissection. This study aimed to assess both the ELITE model in a surgical training course and the construct validity of a newly developed NOTES appendectomy scenario. The 70 attendees of the 2010 Practical Course for Visceral Surgery (Warnemuende, Germany) took part in the study and performed a NOTES appendectomy via a transsigmoidal access. The primary end point was the total time required for the appendectomy, including retrieval of the appendix. Subjective evaluation of the model was performed using a questionnaire. Subgroups were analyzed according to laparoscopic and endoscopic experience. The participants with endoscopic or laparoscopic experience completed the task significantly faster than the inexperienced participants (p = 0.009 and 0.019, respectively). Endoscopic experience was the strongest influencing factor, whereas laparoscopic experience had limited impact on the participants with previous endoscopic experience. As shown by the findings, 87.3% of the participants stated that the ELITE model was suitable for the NOTES training scenario, and 88.7% found the newly developed model anatomically realistic. This study was able to establish face and construct validity for the ELITE model with a large group of surgeons. The ELITE model seems to be well suited for the training of NOTES as a new surgical technique in an established gastrointestinal surgery skills course.

Effect of percutaneous transluminal angioplasty on the stenosis of autogenous radiocephalic ateriovenous fistula for hemodialysis

Energy Technology Data Exchange (ETDEWEB)

Jeong, Sun Min; Kim, Jeong Ho; Byun, Sung Su; Kang, Jin MMo; Choi, Sang Tae; Kim, Jong Woo; Kim, Hyung Sik; Choi, Hye Young [Gachon University Gil Medical Center, Incheon (Korea, Republic of); Park, Jae Hyung [Dept. of Radiology, Seonam University College of Medicine, Myongji Hospital, Goyang (Korea, Republic of)

2016-02-15

The purpose of this study was to evaluate the effectiveness of percutaneous transluminal angioplasty (PTA) on stenosis of autogenous radiocephalic arteriovenous fistula (RCF) for hemodialysis and to determine the factors influencing patency. This retrospective study included 136 patients referred for PTA of RCF stenosis between March 2005 and July 2014. The technical success rate, complications, and patency rate were evaluated. The following factors were analyzed as they might influence patency: age, gender, site and duration of arteriovenous fistula, underlying disease, body mass index, hypercholesterolemia, smoking, peripheral artery or coronary artery occlusive disease, stenosis length/grade, cutting balloon, and balloon size. The initial technical success rate was 91.9% (125/136). Complications included vessel rupture (n = 2) and vessel dissection (n = 2). The patency rates at 6, 12, 24, and 48 months after PTA were 81.9, 67.1, 52.7, and 42.3%, respectively. The patency rate was higher in cases with longer (> 3 cm) stenosis (p = 0.04). Use of cutting balloon and larger size of balloon catheter made the patency longer, but this difference was not statistically significant (p = 0.637, 0.258). PTA is a safe and effective way to manage stenosis in RCF. The length of stenosis was the only factor which affected the patency rate in this study.

Efficacy of 24-Hour Blood Pressure Monitoring in Evaluating Response to Percutaneous Transluminal Renal Angioplasty.

Science.gov (United States)

Jujo, Kentaro; Saito, Katsumi; Ishida, Issei; Furuki, Yuho; Ouchi, Taisuke; Kim, Ahsung; Suzuki, Yuki; Sekiguchi, Haruki; Yamaguchi, Junichi; Ogawa, Hiroshi; Hagiwara, Nobuhisa

2016-08-25

Percutaneous transluminal renal angioplasty (PTRA) improves patency in atherosclerotic renal artery stenosis (ARAS), but improvement in clinic blood pressure (BP) is seen in only 20-40% of patients who undergo PTRA. This study investigated the effects of PTRA on BP lowering, assessed on 24-h ambulatory BP monitoring (ABPM), and identified preoperative features predictive of satisfactory BP improvement after PTRA. Of 1,753 consecutive patients undergoing coronary angiography, 31 patients with angiographically significant ARAS and translesional pressure gradient (TLPG) >20 mmHg underwent PTRA. ABPM was performed before, at 1 month and at 1 year after PTRA; patients with average systolic ABPM-BP decrease >10 mmHg at 1 month from baseline were categorized as responders. There was no obvious relationship between clinic BP and ABPM-BP at baseline. ABPM-BP was significantly higher in responders at baseline (SBP: 148 vs. 126 mmHg, PABPM-BP achieved a larger decrease in ABPM-BP, but the severity of stenosis reflected by TLPG; renal duplex findings; and neurohumoral parameters other than baseline renal function, did not differ between the groups. Clinic BP does not represent daily hemodynamic status, whereas high ABPM-BP is a potent predictor of satisfactory BP response to PTRA. (Circ J 2016; 80: 1922-1930).

Restenosis after stenting in symptomatic vertebral arterial orifice disease and considerations for better outcome

Science.gov (United States)

Chang, Jun Young; Park, Hyun; Kwon, Oki

2017-01-01

We have performed stenting in 11 patients with symptomatic vertebral arterial orifice stenosis refractory to medical treatment or impairment in anterior circulation. Three of the 11 patients experienced asymptomatic severe in-stent restenosis or occlusion. Bare metal stents were used in those three patients, two of whom received revascularization therapy. Development of sufficient cervical collateral channels reconstituting the distal vertebral artery was the common feature in patients with asymptomatic in-stent restenosis. In selecting appropriate stents, consideration of mechanical strength and drug-eluting properties of a stent according to characteristics of the target vessel is important to reduce the risk of in-stent restenosis. Any decision to perform revascularization should be based on the presence of abundant cervical collaterals as well as clinical symptoms of vertebrobasilar ischemia. PMID:28304206

Transcatheter pledget-assisted suture tricuspid annuloplasty (PASTA) to create a double-orifice valve.

Science.gov (United States)

Khan, Jaffar M; Rogers, Toby; Schenke, William H; Greenbaum, Adam B; Babaliaros, Vasilis C; Paone, Gaetano; Ramasawmy, Rajiv; Chen, Marcus Y; Herzka, Daniel A; Lederman, Robert J

2018-02-06

Pledget-assisted suture tricuspid valve annuloplasty (PASTA) is a novel technique using marketed equipment to deliver percutaneous trans-annular sutures to create a double-orifice tricuspid valve. Tricuspid regurgitation is a malignant disease with high surgical mortality and no commercially available transcatheter solution in the US. Two iterations of PASTA were tested using trans-apical or trans-jugular access in swine. Catheters directed paired coronary guidewires to septal and lateral targets on the tricuspid annulus under fluoroscopic and echocardiographic guidance. Guidewires were electrified to traverse the annular targets and exchanged for pledgeted sutures. The sutures were drawn together and knotted, apposing septal and lateral targets, creating a double orifice tricuspid valve. Twenty-two pigs underwent PASTA. Annular and chamber dimensions were reduced (annular area, 10.1 ± 0.8 cm 2 to 3.8 ± 1.5 cm 2 (naïve) and 13.1 ± 1.5 cm 2 to 6.2 ± 1.0 cm 2 (diseased); septal-lateral diameter, 3.9 ± 0.3 mm to 1.4 ± 0.6 mm (naïve) and 4.4 ± 0.4 mm to 1.7 ± 1.0 mm (diseased); and right ventricular end-diastolic volume, 94 ± 13 ml to 85 ± 14 ml (naïve) and 157 ± 25 ml to 143 ± 20 ml (diseased)). MRI derived tricuspid regurgitation fraction fell from 32 ± 12% to 4 ± 5%. Results were sustained at 30 days. Pledget pull-through force was five-fold higher (40.6 ± 11.7N vs 8.0 ± 2.6N, P PASTA reduces annular dimensions and tricuspid regurgitation in pigs. It may be cautiously applied to selected patients with severe tricuspid regurgitation and no options. This is the first transcatheter procedure, to our knowledge, to deliver standard pledgeted sutures to repair cardiac pathology. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Injection and spray characteristics of a variable orifice nozzle applied the jerk type fuel injection pump for DI diesel engine; Jerk shiki nenryo funsha pump wo mochiita kahen funko nozzle no funsha funmu tokusei

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, T; Matsui, K; Iwasaki, T; Kobayashi, T [Zexel Corp., Tokyo (Japan); Matsumoto, Y [The University of Tokyo, Tokyo (Japan)

1997-10-01

A Variable Orifice Nozzle (VON) by changing a cross-sectional area of the nozzle injection hole, for improving a rate of injection and injection duration, has been developed to study its injection and spray characteristics. The nozzle geometry was optimized to analyze a nozzle internal flow by computational method. Results show that, injection and spray pattern responded to the nozzle orifice cross-sectional area which is changing larger to smaller in the part load range. This results suggest to contribute a combustion improvement which decreasing NOx and soot. 14 refs., 10 figs.

A study on the root cause identification of local wall thinning caused by deflected turbulent flow inside orifice of carbon steel components

International Nuclear Information System (INIS)

Park, S. H.; Kim, K. H.; Hwang, K. M.

2010-01-01

When components made of carbon steel in nuclear, fossil, and industry plants are exposed to flowing fluid, wall thinning caused by FAC (flow accelerated corrosion) can be generated and eventually ruptured at the portion of pressure boundary. A study to identify the locations generating local wall thinning and to disclose turbulence coefficients related to the local wall thinning was performed. Experiments and numerical analyses for orifice of down-scaled piping components were performed and the results were compared. Based on the results that the flow behaviors inside piping components can be simulated by numerical analysis, numerical analyses for magnified models to actual size of plants were performed. To disclose the relationship between turbulence coefficients and local thinning rate, numerical analyses were preformed for orifice components included in the main feedwater systems. The turbulence coefficients based on the numerical analyses were compared with the local wear rate based on the measured data. From the comparison of the results, the vertical flow velocity component (Vr) flowing to the wall after separating in the wall due to the geometrical configuration and colliding with the wall directly at an angle of some degree was analogous to the configuration of local wall thinning. (authors)

Per-oral endoscopic myotomy for achalasia: An American perspective

Science.gov (United States)

Friedel, David; Modayil, Rani; Iqbal, Shahzad; Grendell, James H; Stavropoulos, Stavros N

2013-01-01

Achalasia is an uncommon esophageal motility disorder characterized by the selective loss of enteric neurons leading to absence of peristalsis and impaired relaxation of the lower esophageal sphincter. Per-oral endoscopic myotomy (POEM) is a novel modality for the treatment of achalasia performed by gastroenterologists and surgeons. It represents a natural orifice transluminal endoscopic surgery (NOTES) approach to Heller myotomy. POEM has the minimal invasiveness of an endoscopic procedure that can duplicate results of the surgical Heller myotomy. POEM is conceptually similar to a surgical myotomy without the inherent external incisions and post-operative care associated with surgery. Initial high success and low complications rates promise a great future for this technique. In fact, POEM has been successfully performed on patients with end-stage achalasia as an initial treatment reserving esophagectomy for those without good response. The volume of POEMs performed worldwide has grown exponentially. In fact, surgeons who have performed Heller myotomy have embraced POEM as the preferred intervention for achalasia. However, the niche of POEM remains to be defined and long term results are awaited. We describe our experience with POEM having performed the first POEM outside of Japan in 2009, the evolution of our technique, and give our perspective on its future. PMID:24044040

Comparison and Efficacy of LigaSure and Rubber Band Ligature in Closing the Inflamed Cecal Stump in a Rat Model of Acute Appendicitis

Directory of Open Access Journals (Sweden)

Chun-Chieh Yeh

2015-01-01

Full Text Available Safety of either LigaSure or rubber band in closing inflamed appendiceal stump in acute appendicitis has been less investigated. In this study, cecal ligation followed by resecting inflamed cecum was performed to mimic appendectomy in a rat model of acute appendicitis. Rats were sacrificed immediately (Group A and 7 days (Group B after cecal resection, respectively. The cecal stumps were closed by silk ligature (S, 5 mm LigaSure (L, or rubber band (R. Seven days after cecal resection, the LigaSure (BL and silk subgroups (BS had significantly less intra-abdominal adhesion and better laparotomy wound healing than rubber band subgroup (BR. The initial bursting pressure at cecal stump was comparable among the three methods; along with tissue healing process, both BL and BS provided a higher bursting pressure than BR 7 days after appendectomy. BL subgroup had more abundant hydroxyproline deposition than BS and BR subgroup. Furthermore, serum TNF-α in BR group kept persistently increasing along with time after cecal resection. Thus, the finding that LigaSure but not rubber band is safe in sealing off the inflamed cecal stump in rat model of acute appendicitis suggests the possibility of applying LigaSure for appendectomy via single port procedure or natural orifice transluminal endoscopic surgery (NOTES.

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

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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.

Oxide deposition in the orifices of AGR boiler inlet ferrule assemblies

International Nuclear Information System (INIS)

Thomas, D.M.

1988-08-01

In experiments designed to study the erosion-corrosion behaviour of AGR boiler inlet ferrules using the CERL high velocity circulating isothermal water rig, oxide deposition was frequently found within the flow control orifices. The present investigation was carried out as a preliminary to a programme of experiments addressed specifically to this problem. Analysis shows the deposits to be predominantly magnetite (or possible maghemite) with traces of α-haematite. Calculations indicate that the maximum rate of magnetite deposition is mass transfer limited, although in some experiments no deposition occurred in cases where mass transfer would have allowed substantial deposition. Thus the occurrence of deposition is thought to depend on the rig potential as this varies with experimental conditions. In these experiments the surface potential is not found to be governed by the hydrogen level. Metallographic cross-sections through the ferrule control bores show the deposits to be found in regions of separated flow, and the flow markings in the deposits show that the flow is turbulent in these zones. The exact morphology is thought to be influenced by machining marks within the control bore. (author)

Fabrication and Application of Mono-sized Spherical Micro Particles by Pulsated Orifice Ejection Method

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DONG Wei

2018-02-01

Full Text Available A novel technology called pulsated orifice ejection method(POEM and used for preparing mono-sized and high-precision spherical micro particles was introduced in this article. The working principle of the technique was illustrated and it was in two modes:low-melting point diaphragm mode and high-melting point rod mode, depending on the different melting points of materials. The particles prepared by POEM have the advantages of mono-sized, uniform and controllable particle size, high sphericity, and consistent thermal history. By introducing the application of particles prepared by this method, showing the huge application prospects of this technology in electronic packaging, bioengineering, micro-fabrication, rapid solidification analysis of metal droplets, additive manufacturing and so on.With the development of POEM, this technology is predicted to have wider prospects due to its unique characteristics.

Ablación miocárdica septal transluminal percutánea en pacientes con miocardiopatía hipertrófica septal obstructiva: Resultados agudos y seguimiento a 3 años

OpenAIRE

Llamas-Esperón,Guillermo A.; Loera Pinales,Armando; Sandoval Navarrete,Santiago; Zamora Muciño,Alberto; Ramírez Robledo,Miguel A.; Varela Ortiz,Samuel; Casas Juárez,Ulices; Fuantos Delgado,María de la Luz; Albarrán Domínguez,Javier; Muñoz Sandoval,Rocío; Sandoval Rodríguez,Eufracino; Ruiz Esparza,M. Eugenia

2009-01-01

Objetivo: Reportar los resultados agudos y a largo plazo de la ablación miocárdica septal transluminal percutánea (AMSTP) como tratamiento de la miocardiopatía hipertrófica septal obstructiva (MHSO). La AMSTP se considera una alternativa del tratamiento quirúrgico en pacientes con MHSO y sintomatología refractaria a otras opciones de tratamiento. La respuesta aguda suele ser satisfactoria, pero los resultados a largo plazo no se han descrito de forma suficiente. Métodos: Realizamos AMSTP en 8...

High-Flow Nasal Cannula Therapy in a Patient with Reperfusion Pulmonary Edema following Percutaneous Transluminal Pulmonary Angioplasty

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Kiyoshi Moriyama

2014-01-01

Full Text Available A 62-year-old woman with Wolff-Parkinson-White syndrome was with recent worsening of dyspnea to New York Heart Association functional status Class III. The patient was diagnosed as having central type chronic thromboembolic pulmonary hypertension. By cardiac catheterization, her mean pulmonary artery pressure was 53 mmHg with total pulmonary resistance 2238 dynes·sec·cm−5. After medical therapies with tadalafil, furosemide, ambrisentan, beraprost, and warfarin were initiated, percutaneous transluminal pulmonary angioplasty (PTPA was performed. Following PTPA, life-threating hypoxemia resulting from postoperative reperfusion pulmonary edema developed. High-flow nasal cannula therapy (HFNC was applied, and 100% oxygen at 50 L/min of flow was required to keep oxygenation. HFNC was continued for 3 days, and the patient was discharged on 8th postoperative day with SpO2 of 97% on 3 L/min of oxygen inhalation. Because of the simplicity of the technique, the lower cost of equipment, and remarkable patient tolerance to the treatment, we speculate that HFNC can take over the post of noninvasive ventilation as first-line therapy for patients with acute respiratory failure.

The Use of Below-Knee Percutaneous Transluminal Angioplasty in Arterial Occlusive Disease Causing Chronic Critical Limb Ischemia

International Nuclear Information System (INIS)

Loefberg, Ann-Marie; Loerelius, Lars-Erik; Karacagil, Sadettin; Westman, Bo; Almgren, Bo; Berqgvist, David

1996-01-01

Purpose: To determine the efficacy, safety and long-term results of crural artery percutaneous transluminal angioplasty (PTA) in limbs with chronic critical limb ischemia (CLI). Methods: Patients undergoing crural artery PTA due to CLI were followed at regular clinic visits with ankle brachial pressure index (ABPI) measurements. PTA of the crural arteries was attempted either alone (n= 39) or in combination with PTA of the superficial and/or popliteal artery (n= 55) in 86 limbs (82 patients and 94 procedures) presenting with CLI. The ages of patients ranged from 37 to 94 years (mean 72 years). The indications for PTA were rest pain in 10 and ulcer/gangrene in 84 limbs.Results: A technically successful PTA with at least one crural level was achieved in 88% of cases (n= 83). Cumulative primary clinical success rates at 6, 12, 24, and 36 months were 55%, 51%, 36%, and 36%, respectively. Cumulative secondary clinical success and limb salvage rates at 36 months were 44% and 72%, respectively. Conclusion: PTA of the crural arteries might be considered the primary choice of treatment in patients with CLI and distal lesions with localized stenosis or segmental short occlusions

Clinical application of hepatic vein percutaneous transluminal angioplasty and stent after stent placement in inferior vena cava

International Nuclear Information System (INIS)

Xu Hao; Zu Maoheng; Gu Yuming; Li Guojun; Zhang Qingqiao; Wei Ning; Xu Wei; Liu Hongtao

2005-01-01

Objective: To investigate the feasibility and effect of recanalization of hepatic vein with percutaneous transluminal angioplasty (PTA) and stent after stent placement in inferior vena cava (IVC). Methods: Eleven patients with Budd-Chiari syndrome (BCS)were once performed metal stent placement in IVC at other hospital, but ascites was not subsided in 9 patients after the stent placement and occurred again in 2 patients in 3 months after the procedure. PTA and metal stent placement were used to treat the occlusion of the hepatic vein (HV) via stent in IVC. Results: Recanalization of occlusive HV was successful in all 11 patients, and symptoms disappeared or were obviously improved. The mean blood pressure in HV dropped from pre-operation (45.12 ± 1.57) cm H 2 O (1 cm H 2 O=0.098 kPa) to post-operation (17.53 ± 0.68) cm H 2 O (P<0.01). In a period of 4-30 months (mean: 13.6 months) following-up, no patient reoccurred symptoms. Conclusion: Recanalization of HV via stent in IVC is a feasible and effective method for occlusive HV, but it is difficult. (authors)

Evaluation of effective regurgitant orifice area of mitral valvular regurgitation by multislice cardiac computed tomography

International Nuclear Information System (INIS)

Vural, M.; Ucar, O.; Celebi, O.O.; Cicekcioglu, H.; Durmaz, H.A.; Selvi, N.A.; Koparal, S.; Aydogdu, S.

2010-01-01

The purpose of our study was to assess the diagnostic accuracy of multislice computed tomography (MSCT) for the identification and quantification of mitral valve regurgitation in comparison with transthoracic echocardiography (TTE). Twenty-six patients (15 females, 11 males with a mean age of 44.6±14.1 years) who were in follow-up with the diagnosis of mitral regurgitation and those who were referred for MSCT were enrolled. MSCT results were compared with TTE measurements. The mean effective mitral regurgitant orifice area at MSCT was 23.1±13.0 mm 2 and at echocardiography was 24.4±16.0mm 2 . Bland-Altman analysis showed good agreement between the two imaging methods. MSCT provides reliable and good results for the evaluation of mitral regurgitation. (author)

The role of percutaneous transluminal coronary angioplasty in heart transplant recipients.

Science.gov (United States)

Schnetzler, B; Drobinski, G; Dorent, R; Camproux, A C; Ghossoub, J; Thomas, D; Gandjbakhch, I

2000-06-01

Review the acute and late results of percutaneous transluminal coronary angioplasty (PTCA) in heart transplant recipients and examine the factors predictive of restenosis. Coronary graft disease (CGD) is the main factor responsible for late graft loss. Medical treatment, surgical revascularization, or retransplantation gives only suboptimal results in this regard. Therefore, PTCA has been attempted in this situation. More than 332 heart transplantations in our institution have been performed since 1992, the date of the first PTCA in our patients. We are currently in charge of 450 patients. All the characteristics, procedure-related information, and clinical outcome of patients needing PTCA were assessed by review of each patient's clinical records. All coronary angiograms were reviewed by an independent cardiologist. Since 1992, 53 coronary sites have been dilated in the course of 39 procedures in 29 patients. Indication for PTCA was asymptomatic angiographic coronary graft disease in 35 sites (64.8%), angina in 9 (16.6%), silent ischemia in 2 (3.7%), acute myocardial infarction in 1 (1.8%), and CHF in 7 (12.9%). Primary success ( 50%) was 32.5% (14/43). Mean follow-up was 1.27 year +/- 1.2 (SD). Five deaths (17. 2%) occurred in follow-up and were all in relation to coronary graft disease. Mean time separating PTCA from death was 0.9 year +/- 1.3 (SD). We also sought to look at factors predictive of restenosis. By multivariate analysis, a positive recipient's serology for cytomegalovirus (CMV) before the graft was the only factor found protective against restenosis (odds ratio 22.4; confidence interval 1.1 to 443.4). PTCA in heart transplant recipients allows a high level of primary success with a low periprocedural-complication rate. Restenosis rate seems equivalent to restenosis rate in native coronary arteries. Mortality during follow-up is increased in this population and is the consequence of a high level of coronary events. Recipient positivity for CMV before

THE PERFORMANCE ANALYSIS OF A PACKED COLUMN : CALIBRATION OF AN ORIFICE

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Aynur ŞENOL

2003-01-01

Full Text Available Investigations to develop data for this study were made using a pilot scale glass column of 9 cm inside diameter randomly filled to a depth of 1.90 cm with a Raschig type ring at a slightly modified geometry. The geometrical characteristics of packing are: the total area of a single particle ad = 2.3 cm2; specific area ap = 10.37 cm2/cm3; voidage ? = 0.545 m3/m3. The efficiency tests were run using trichloroethylene/n-heptane system under total reflux conditions. Using the modified versions of the Eckert flooding model and the Bravo effective area (ae approach, as well as the Onda wetted area (aw and individual mass transfer coefficient models, it has been attempted to estimate the packing efficiency theoretically. This article also deals with the design strategies attributed to a randomly packed column. Emphasis is mainly placed on the way to formulate an algorithm of designing a pilot scale column through the models being attributed to the film theory. Using the column dry pressure drop properties based on the air flowing it has been achieved a generalized flow rate approach for calibrating of an orifice through which the air passes.

Membranous obstruction of inferior vena cava(MOIVC): treatment with percutaneous transluminal angioplasty(PTA) and self expandable metallic stent

Energy Technology Data Exchange (ETDEWEB)

Lee, Ki Yeol; Kim, Baek Hyun; Cha, In Ho; Lee, Nam Joon; Kim, Yun Hwan; Kim, Jung Hyuk [College of Medicine, Korea University, Seoul (Korea, Republic of)

1994-03-15

Percutaneous transluminal angioplasty(PTA) with a balloon catheter is a standard method of treatment for membranous obstruction of inferior vena cava(MOIVC). But, correct therapeutic approach has not been established for MOIVC patients whose lesion is associated with extensive thrombotic IVC occlusion. We tried to treat MOIVC associated with or without thrombus. We treated 13 cases of MOIVC(associated with thrombus in 7 cases, no thrombus in 6 cases) with PTA, thrombolysis and self-expandable metallic stents. PTA was successful in 8 cases, but failed in 5 cases. The recurred cases were retreated with PTA, but follow-up study revealed recoiling restenosis in 4 cases and intimal hyperplasia in 1 case at previous PTA site which could be overcome with a self-expandable metallic stent. The complication were occurred in 3 cases which were hemothorax, hemopericardium, and hemoperitoneum respectively. However, those were resolved by conservative treatment only. Recanalization and dilatation could be done in MOIVC patients with or without thrombosis for improvement of patient's symptom. Gianturco self-expandable metallic stent is useful in treatment of recurred MOIVC after balloon dilatation and preventing reocclusion of the IVC after PTA.

Quantitative exercise thallium-201 scintigraphy for predicting angina recurrence after percutaneous transluminal coronary angioplasty

International Nuclear Information System (INIS)

Stuckey, T.D.; Burwell, L.R.; Nygaard, T.W.; Gibson, R.S.; Watson, D.D.; Beller, G.A.

1989-01-01

The aim of this prospective study was to determine the value of quantitative exercise thallium-201 scintigraphy for predicting short-term outcome in patients after percutaneous transluminal coronary angioplasty (PTCA). Quantitative exercise thallium-201 scintigraphy was performed 2.2 +/- 1.2 weeks after successful PTCA in 68 asymptomatic patients, 64 (94%) of whom had class III or IV angina before the procedure. Clinical follow-up was obtained in all patients at a mean of 10 +/- 2 months and all were followed for at least 6 months; 45 patients (66%) remained asymptomatic during follow-up and 23 (34%) developed recurrent class III or IV angina at a mean of 2.6 +/- 1.2 months. Multivariate analysis of 22 clinical, angiographic and exercise test variables revealed that thallium-201 redistribution, any thallium scan abnormality, presence of a distal stenosis and treadmill time were the only significant predictors of recurrent angina after PTCA. Using a stepwise discriminant function model, thallium-201 redistribution was the only significant independent predictor. Despite its prognostic value relative to other variables as a predictor, thallium redistribution at 2 weeks after PTCA was only detected in 9 of the 23 patients (39%) who subsequently developed recurrent angina, although only 2 of the 45 patients (9%) who remained asymptomatic during follow-up demonstrated thallium-201 redistribution at the time of early testing. After repeat angiography was performed in 17 of the 23 patients with recurrent angina, 14 (82%) demonstrated restenosis and 3 (18%) had worse narrowing distal to or remote from the site of dilatation

Modelling of fluid flow through short tube orifices under metastable conditions: A new numerical validation approach for evaluating the mass flow rate with refrigerant mixtures (HFC-407C and HFC-410A)

International Nuclear Information System (INIS)

García-Valladares, O.; Santoyo, E.

2014-01-01

In a previous work, one-dimensional numerical modelling of fluid-flow inside short tube orifices was performed, and successfully validated against a wide range of mass flow rate measurements reported for the refrigerant HFC-134a. Governing equations of continuity, momentum, energy and entropy were solved for describing the fluid flow under a wide variety of thermodynamic transitions (e.g., subcooled liquid region, metastable liquid region, metastable two-phase region and equilibrium two-phase region), including sudden contraction and enlargement. In this new study, a comprehensive comparison analysis between numerical simulation data and experimental measurements obtained for HFC-407C and HFC-410A refrigerants (N o  = 241) to extend the applicability of the same mathematical model was carried out. Using a widespread statistical analysis, based on weighted linear regressions with an outlier detection/rejection module at 95% of confidence level, the prediction performance of the mathematical model was again assessed. Linear regressions between predicted mass flow rate data and experimental measurements were computed, and used them as a statistical comparison criterion. A statistical comparison between predicted simulation results and mass flow rate experimental data are reported. Average deviation errors of ±11.1% (for the refrigerant HFC-407C) and ±7.3% (for refrigerant HFC-410A) were found between numerical model and experimental data. These results demonstrate a new and robust application of the model to predict reliably the mass flow rate through short tube orifices under metastable conditions, which enable this tool to be reliably used for the design of short tube orifices. - Highlights: •A modelling for evaluating short tube orifice was developed for refrigerant mixtures. •The numerical model applied considered metastable regions and choke flow. •The model was validated against experimental data for HFC-407C and HFC-410A. •Statistical analysis based

Triple-orifice valve repair in severe Barlow disease with multiple-jet mitral regurgitation: report of mid-term experience.

Science.gov (United States)

Fucci, Carlo; Faggiano, Pompilio; Nardi, Matilde; D'Aloia, Antonio; Coletti, Giuseppe; De Cicco, Giuseppe; Latini, Leonardo; Vizzardi, Enrico; Lorusso, Roberto

2013-09-10

Barlow disease represents a surgical challenge for mitral valve repair (MR) in the presence of mitral insufficiency (MI) with multiple regurgitant jets. We hereby present our mid-term experience using a modified edge-to-edge technique to address this peculiar MI. From March 2003 till December 2010, 25 consecutive patients (mean age 54 ± 7 years, 14 males) affected by severe Barlow disease with multiple regurgitant jets were submitted to MR. Preoperative transesophageal echo (TEE) in all the cases showed at least 2 regurgitant jets, involving one or both leaflets in more than one segment. In all the patients, a triple orifice valve (TOV) repair with annuloplasty was performed. Intra-operative TEE and postoperative transthoracic echocardiography (TTE) were carried out to evaluate results of the TOV repair. There was no in-hospital death and one late death (non-cardiac related). At intra-operative TEE, the three orifices showed a mean total valve area of 2.9 ± 0.1cm(2) (range 2.5-3.3 cm(2)) with no residual regurgitation (2 cases of trivial MI) and no sign of valve stenosis (mean transvalvular gradient 4.6 ± 1.5 mmHg). At follow up (mean 38 ± 22 months), TTE showed favourable MR and no recurrence of significant MI (6 cases of trivial and 1 of mild MI). Stress TTE was performed in 5 cases showing persistent effective valve function (2 cases of trivial MI at peak exercise). All the patients showed significant NYHA functional class improvement. This report indicates that the TOV technique is effective in correcting complex Barlow mitral valves with multiple jets. Further studies are required to confirm long-term applicability and durability in more numerous clinical cases. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Gonioscopy-assisted Transluminal Trabeculotomy: An Ab Interno Circumferential Trabeculotomy: 24 Months Follow-up.

Science.gov (United States)

Grover, Davinder S; Smith, Oluwatosin; Fellman, Ronald L; Godfrey, David G; Gupta, Aditi; Montes de Oca, Ildamaris; Feuer, William J

2018-05-01

The purpose of this study was to provide 24-month follow-up on surgical success and safety of an ab interno circumferential 360-degree trabeculotomy. Chart review of patients who underwent a gonioscopy-assisted transluminal trabeculotomy (GATT) procedure was performed by 4 of the authors (D.S.G., O.S., R.L.F., and D.G.G.). The surgery was performed in adults with various types of open-angle glaucoma with preoperative intraocular pressures (IOPs) of ≥18 mm Hg. In total, 198 patients aged 24 to 89 years underwent the GATT procedure with at least 18 months follow-up. Patients with primary open-angle glaucoma had an average IOP decrease of 9.2 mm Hg at 24 months with an average decrease of 1.43 glaucoma medications. The mean percentage of IOP decrease in these primary open-angle glaucoma groups at 24 months was 37.3%. In secondary open-angle glaucoma, at 24 months there was an average decrease in IOP of 14.1 mm Hg on an average of 2.0 fewer medications. The mean percentage of IOP decrease in the secondary open-angle glaucoma groups at 24 months was 49.8%. The cumulative proportion of failure at 24 months ranged from 0.18 to 0.48, depending on the group. In all 6 study groups, at all 5 postoperative time points (3, 6, 12, 18, and 24 mo) the mean IOP and reduction in glaucoma medications was significantly reduced from baseline (P<0.001) with the exception of one time point. The 24-month results demonstrate that GATT is relatively safe and effective in treating various forms of open-angle glaucoma. The long-term results for GATT are relatively equivalent to those previously reported for GATT and ab externo trabeculotomy studies.

Taking NOTES: translumenal flexible endoscopy and endoscopic surgery.

Science.gov (United States)

Willingham, Field F; Brugge, William R

2007-09-01

To review the current state of natural orifice surgery and examine the concerns, challenges, and opportunities presented by translumenal research. Translumenal endoscopic procedures have been the focus of extensive research. Researchers have reported natural orifice translumenal endoscopic surgery in a swine model in several areas involving the abdominal cavity. Diagnostic procedures have included endoscopic peritoneoscopy, liver biopsy, lymphadenectomy, and abdominal exploration. Several gynecologic procedures including tubal ligation, oophorectomy, and partial hysterectomy have been demonstrated using current commercial endoscopes. Gastrointestinal surgical procedures, including gastrojejunostomy, cholecystectomy, splenectomy, and distal pancreatectomy have been performed successfully via transgastric and/or transcolonic approaches. There have been no studies of natural orifice translumenal endoscopic surgery procedures published in humans. While fundamental questions about the emerging technology have not been scrutinized, limitations of the large animal model will pose a challenge to the development of large randomized trials. While natural orifice translumenal endoscopic surgery may represent a paradigm shift and may offer significant benefits to patients, rigorous testing of the techniques is lacking and current data have been drawn from case series.

Update on Instrumentations for Cholecystectomies Performed via Transvaginal Route: State of the Art and Future Prospectives

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Elia Pulvirenti

2010-01-01

Full Text Available Natural Orifice Transluminal Endoscopic Surgery (NOTES is an innovative approach in which a flexible endoscope enters the abdominal cavity via the transesophageal, transgastric, transcolonic, transvaginal or transvescical route, combining the technique of minimally invasive surgery with flexible endoscopy. Several groups have described different modifications by using flexible endoscopes with different levels of laparoscopic assistance. Transvaginal cholecystectomy (TVC consists in accessing the abdominal cavity through a posterior colpotomy and using the vaginal incision as a visual or operative port. An increasing interest has arisen around the TVC; nevertheless, the most common and highlighted concern is about the lack of specific instruments dedicated to the vaginal access route. TVC should be distinguished between “pure”, in which the entire operation is performed through the transvaginal route, and “hybrid”, in which the colpotomy represents only a support to introduce instruments and the operation is performed mainly by the classic transabdominal-introduced instruments. Although this new technique seems very appealing for patients, on the other hand it is very challenging for the surgeon because of the difficulties related to the mode of access, the limited technology currently available and the risk of complications related to the organ utilized for access. In this brief review all the most recent advancements in the field of TVC's techniques and instrumentations are listed and discussed.

The future of NOTES from the conservative point of view.

Science.gov (United States)

Kano, Nobuyasu

2009-01-01

Recently, the unfamiliar term "natural orifice transluminal endoscopic surgery (NOTES)" appeared in my field. Actually, I am hesitant to accept this technique in my surgical practice. In this paper, I will review some references and try to establish my position toward NOTES. The author has been skeptical and ironical about the clinical potentiality of NOTES since hearing the presentation about NOTES for the first time. I have been concerned about making a puncture in the gastrointestinal tract as an old surgeon who believes that intestinal injury must not occur during surgery. However, recent advances in the research of NOTES are changing my stubborn belief. What I have to do is to avoid interrupting or disturbing young surgeons' challenges to develop NOTES. I remember that some senior surgeons were against us when we started laparoscopic surgery around 1990. Senior surgeons and physicians must be generous, considerate, helpful and supportive to our followers. I have been enthusiastic about the development and spread of laparoscopic surgery since 1987 and have been doing various surgical procedures myself, including those involving the biliary tract, pancreas, spleen, upper and lower gastrointestinal tract, adrenal, kidney and gynecologic organs. Recently, the unfamiliar term "NOTES" appeared in my field. Actually, I am hesitant to accept this technique in my surgical practice. In this paper I will review some references and try to establish my position toward NOTES.

Transvaginal Appendectomy: A Systematic Review

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Mehmet Ali Yagci

2014-01-01

Full Text Available Background. Natural orifice transluminal endoscopic surgery (NOTES is a new approach that allows minimal invasive surgery through the mouth, anus, or vagina. Objective. To summarize the recent clinical appraisal, feasibility, complications, and limitations of transvaginal appendectomy for humans and outline the techniques. Data Sources. PubMed/MEDLINE, Cochrane, Google-Scholar, EBSCO, clinicaltrials.gov and congress abstracts, were searched. Study Selection. All related reports were included, irrespective of age, region, race, obesity, comorbidities or history of previous surgery. No restrictions were made in terms of language, country or journal. Main Outcome Measures. Patient selection criteria, surgical techniques, and results. Results. There were total 112 transvaginal appendectomies. All the selected patients had uncomplicated appendicitis and there were no morbidly obese patients. There was no standard surgical technique for transvaginal appendectomy. Mean operating time was 53.3 minutes (25–130 minutes. Conversion and complication rates were 3.6% and 8.2%, respectively. Mean length of hospital stay was 1.9 days. Limitations. There are a limited number of comparative studies and an absence of randomized studies. Conclusions. For now, nonmorbidly obese females with noncomplicated appendicitis can be a candidate for transvaginal appendectomy. It may decrease postoperative pain and enable the return to normal life and work off time. More comparative studies including subgroups are necessary.

Single port VATS: recent developments in Asia.

Science.gov (United States)

Yu, Peter S Y; Capili, Freddie; Ng, Calvin S H

2016-03-01

Single port video-assisted thoracic surgery (VATS) is the most recent evolution in minimally invasive thoracic surgery. With increasing global popularity, the single port VATS approach has been adopted by experienced thoracic surgeons in many Asian countries. From initial experience of single port VATS lobectomy to the more complex sleeve resection procedures now forming part of daily practice in some Asia institutes, the region has been the proving ground for single port VATS approaches' feasibility and safety. In addition, certain technical refinements in single port VATS lung resection and lymph node dissection have also sprung from Asia. Novel equipment designed to facilitate single port VATS allowing further reduce access trauma are being realized by the partnership between surgeons and the industries. Advanced thoracoscopes and staplers that are narrower and more maneuverable are particularly important in the smaller habitus of patients from Asia. These and similar new generation equipment are being applied to single port VATS in novel ways. As dedicated thoracic surgeons in the region continue to striving for excellence, innovative ideas in single incision access including subxiphoid and embryonic natural-orifice transluminal endoscopic surgery (e-NOTES) have been explored. Adjunct techniques and technology used in association with single port VATS such as non-intubated surgery, hybrid operating room image guidance and electromagnetic navigational bronchoscopy are all in rapid development in Asia.

Diabetes insipidus-like state complicating percutaneous transluminal renal stenting for transplant renal artery stenosis.

Science.gov (United States)

Tian, Lu; He, Yangyan; Zhang, Hongkun; Wu, Ziheng; Li, Donglin; Chen, Shanwen

2014-07-01

To report the incidence, etiology, and treatments of diabetes insipidus-like state that complicate percutaneous transluminal renal stenting (PTRS) for transplant renal artery stenosis (TRAS). Data from 7 patients on whom PTRS for TRAS was performed between October 2008 and March 2012 were reviewed retrospectively. The parameters investigated included blood flow velocity, blood pressure, and creatinine levels before and after the intervention. The procedural success rate was 100%. Three cases developed a diabetes insipidus-like state in the immediate postprocedural period. Urine output returned to normal within 2 weeks after treatment. The median blood flow velocity was significantly reduced from 4.51 m/sec (4.31-4.61 m/sec) at the time of TRAS diagnosis to 1.33 m/sec (1.31-1.51 m/sec) at the most recent follow-up of the group with a diabetes insipidus-like state. The ratio of median blood flow velocity before and after stenting in the group with a diabetes insipidus-like state was significantly higher than that in the group without a diabetes insipidus-like state (3.39 vs. 1.93). Diabetes insipidus-like state that complicates PTRS for TRAS is not an uncommon event, but appears to be underreported in the medical literature. A high ratio of pre- and poststenting median blood flow velocity may be a predictor for a postprocedural diabetes insipidus-like state. The most probable cause may be the marked increase in renal arterial flow. Early recognition of the condition is essential to avoid dehydration and electrolyte imbalance. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of Hydrodynamic Cavitation of a Restriction Orifice on Crud-like Deposits

International Nuclear Information System (INIS)

Kim, Seong Man; Lee, Seung Won; Park, Sung Dae; Kang, Sarah; Seo, Han; Bang, In Cheol

2011-01-01

Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core has shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice fundamentally

Effects of Hydrodynamic Cavitation of a Restriction Orifice on Crud-like Deposits

Energy Technology Data Exchange (ETDEWEB)

Kim, Seong Man; Lee, Seung Won; Park, Sung Dae; Kang, Sarah; Seo, Han; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2011-10-15

Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core has shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice fundamentally

Experimental study of the core grid by-pass orifices inlet pressure drop of the new core of the R A 6 reactor

International Nuclear Information System (INIS)

Masson, V. P; Garcia, J. C; Delmastro, D. F

2006-01-01

In this work the core grid by-pass orifices inlet pressure drop of the new core of the R A6 reactor are experimentally studied.The experiments are performed using a 1:1 scale mock-up of an external fuel element cell.Different gaps between fuel elements are considered in order to take into account the design allowances. Different flows are considered to take into account the normal operation flow range.Measurement uncertainties are included.The results will be used to calculate the core flow distribution [es

Analysis of Simultaneous Gas-Liquid Flow Through an Orifice and Its Application to Flow Metering Etude de l'écoulement simultané d'un mélange gaz-liquide à travers un orifice et son application à la mesure du débit

Directory of Open Access Journals (Sweden)

Pascal H.

2006-11-01

Full Text Available The purpose of this article is to show a more accurate orifice equation for a two-phase flow, such a compressible mixture of gas and liquid. The orifice equation given here con be used for the measurement of a gas-liquid mixture of fine emulsions by the orificemeter method. From the thermodynamic point of view, an equation of state has been formulated which provides the relationship between the specific mass of the mixture and pressure, under conditions of adiabatic expansion. The results obtained enable the mass flow rates of gas and liquid ta be determined without separation of the phases, provided thot the gas liquid mass ratio is known. The critical pressure ratio corresponding ta sonic velocity is also determined. Cet article présente une relation plus précise pour l'écoulement d'un système à deux phases, tel qu'un mélange compressible gaz-liquide, à travers un diaphragme. Cette relation peut être utilisée pour des mesures de mélanges gaz-liquide très finement divisés, c'est-à-dire des émulsions ou brouillards, par la méthode du diaphragme en paroi mince. Du point de vue thermodynamique, on a formulé une équation d'état donnant la relation entre la masse spécifique du mélange et la pression dans des conditions d'expansion adiabatique. Les résultats obtenus per-mettent de déterminer le débit massique du gaz et du liquide, sans séparation des deux phases, à condition que le rapport de masse gaz-liquide soit connu. On détermine également le rapport de pression critique correspondantà la vitesse du son.

Verification procedures of ultrasonic flow meters for natural gas applications; Procedimento de verificacao de medidores ultra-sonicos para gas natural

Energy Technology Data Exchange (ETDEWEB)

Lourenco, Tulio C. [TRANSPETRO, Rio de Janeiro, RJ (Brazil)

2009-12-19

In recent years, the use of ultrasonic flow meters for natural gas applications has grown significantly, especially after the issuance of AGA Report 9 and AGA Report 10. The reasons this technology has stood out from the others, such as orifice-plates or turbines, are: accuracy, wide range ability, it is bi-directional, robustness, low maintenance and, mainly, integrated diagnostic parameters, such as sound velocity, signal quality and profile velocity analysis. TRANSPETRO currently operates 56 ultrasonic natural gas flow-meter systems. For operational control applications, 90% of the meters are ultrasonic, of which 85% are provided with internal diagnostic tools through the manufacturer's software. Within this perspective, it is essential and unquestionable that there are procedures and routines for ultrasonic flow-meter verification and analysis, in order to monitor their performance and integrity, in addition to the early identification of potential problems. This paper discusses the practical application of several tools and diagnostic parameters inherent in ultrasonic flow meters in periodical verifications using TRANSPETRO's procedure. (author)

Efficacy of Ultrasound-Guided Axillary Brachial Plexus Block for Analgesia During Percutaneous Transluminal Angioplasty for Dialysis Access

International Nuclear Information System (INIS)

Chiba, Emiko; Hamamoto, Kohei; Nagashima, Michio; Matsuura, Katsuhiko; Okochi, Tomohisa; Tanno, Keisuke; Tanaka, Osamu

2016-01-01

PurposeTo evaluate the efficacy and safety of ultrasound (US)-guided axillary brachial plexus block (ABPB) for analgesia during percutaneous transluminal angioplasty (PTA) for dialysis access.Subjects and MethodsTwenty-one patients who underwent PTA for stenotic dialysis access shunts and who had previous experience of PTA without sedation, analgesia, and anesthesia were included. The access type in all patients was native arteriovenous fistulae in the forearm. Two radiologists performed US-guided ABPB for the radial and musculocutaneous nerves before PTA. The patients’ pain scores were evaluated using a visual analog scale (VAS) after PTA, and these were compared with previous sessions without US-guided ABPB. The patient’s motor/sensory paralysis after PTA was also examined.ResultsThe mean time required to achieve US-guided ABPB was 8 min. The success rate of this procedure was 100 %, and there were no significant complications. All 21 patients reported lower VAS with US-guided ABPB as compared to without the block (p < 0.01). All patients expressed the desire for an ABPB for future PTA sessions, if required. Transient motor paralysis occurred in 8 patients, but resolved in all after 60 min.ConclusionUS-guided ABPB is feasible and effective for analgesia in patients undergoing PTA for stenotic dialysis access sites.Level of EvidenceLevel 4 (case series).

Percutaneous transluminal angioplasty of malfunctioning Brescia-Cimino arteriovenous fistula: analysis of factors adversely affecting long-term patency

International Nuclear Information System (INIS)

Sugimoto, Koji; Hirota, Shozo; Sugimura, Kazuro; Higashino, Takanori; Kuwata, Yoichiro; Imanaka, Kazufumi

2003-01-01

Our objective was to identify the factors adversely affecting long-term patency after percutaneous transluminal angioplasty (PTA) for hemodialysis Brescia-Cimino arteriovenous fistulas. Between November 1995 and March 2000, 91 PTA procedures were performed on 50 patients with 57 Brescia-Cimino fistulas. A retrospective study based on the chart review was performed. The initial technical success rate for all procedures and the primary and secondary patency rates for all fistulas were calculated. Regarding fistulas successfully maintained by the primary PTA, the primary and secondary patency rates were compared using the Kaplan-Meier method between two patient groups. They were classified on the basis of several factors, including age (older, over 70 years, and younger group), age of the fistulas (older, over 6 months, and younger group), with or without diabetes mellitus (DM), solitary or multiple lesions, long or short segment lesion, stenosis or occlusion, and with or without arterial and/or anastomotic lesions. Initial technical success rates for all procedures and fistulas were 91.2 and 89.5%, respectively. Cumulative primary and secondary patency rates at 1 year were 47.3 and 67.3%, respectively. In the comparative study, the secondary patency rate for the older group was lower than that of the younger group with statistical significance (p =0.029). The higher age is the only factor that reduces the long-term patency rate after PTA. (orig.)

Efficacy of Ultrasound-Guided Axillary Brachial Plexus Block for Analgesia During Percutaneous Transluminal Angioplasty for Dialysis Access

Energy Technology Data Exchange (ETDEWEB)

Chiba, Emiko, E-mail: chibaemi23@comet.ocn.ne.jp; Hamamoto, Kohei, E-mail: hkouhei917@gmail.com [Jichi Medical University, Department of Radiology, Saitama Medical Center (Japan); Nagashima, Michio, E-mail: nagamic00@gmail.com [Asahikawa Medical University, Department of Emergency Medicine (Japan); Matsuura, Katsuhiko, E-mail: kmatsur@gmail.com; Okochi, Tomohisa, E-mail: t-shachi@dj8.so-net.ne.jp; Tanno, Keisuke, E-mail: tankichi1974@gmail.com; Tanaka, Osamu, E-mail: otanaka@omiya.jichi.ac.jp [Jichi Medical University, Department of Radiology, Saitama Medical Center (Japan)

2016-10-15

PurposeTo evaluate the efficacy and safety of ultrasound (US)-guided axillary brachial plexus block (ABPB) for analgesia during percutaneous transluminal angioplasty (PTA) for dialysis access.Subjects and MethodsTwenty-one patients who underwent PTA for stenotic dialysis access shunts and who had previous experience of PTA without sedation, analgesia, and anesthesia were included. The access type in all patients was native arteriovenous fistulae in the forearm. Two radiologists performed US-guided ABPB for the radial and musculocutaneous nerves before PTA. The patients’ pain scores were evaluated using a visual analog scale (VAS) after PTA, and these were compared with previous sessions without US-guided ABPB. The patient’s motor/sensory paralysis after PTA was also examined.ResultsThe mean time required to achieve US-guided ABPB was 8 min. The success rate of this procedure was 100 %, and there were no significant complications. All 21 patients reported lower VAS with US-guided ABPB as compared to without the block (p < 0.01). All patients expressed the desire for an ABPB for future PTA sessions, if required. Transient motor paralysis occurred in 8 patients, but resolved in all after 60 min.ConclusionUS-guided ABPB is feasible and effective for analgesia in patients undergoing PTA for stenotic dialysis access sites.Level of EvidenceLevel 4 (case series).

QUALITY OF LIFE AND COMPLIANCE TO THERAPY IN PATIENTS FOLLOWING SUCCESSFUL TRANSLUMINAL CORONARY ANGIOPLASTY, WHO WERE PRESCRIBED LESCOL XL (FLUVASTATIN ADDED TO STANDARD THERAPY. RESULTS OF THE LESQOL OPEN-LABEL OBSERVATIONAL STUDY

Directory of Open Access Journals (Sweden)

A. V. Susekov

2010-01-01

Full Text Available Aim. The main aim of the present study was to evaluate quality of life changes and compliance to therapy in patients following successful transluminal angioplasty, who were prescribed fluvastatin extended release in addition to standard treatment.Material and methods. This was a national prospective multicenter observational study. Patients with coronary heart disease following successful transluminal coronary angioplasty, who were prescribed fluvastatin extended release (Lescol Forte, Novartis 80 mg QD were included in the present observation. The following efficacy and safety parameters were evaluated: quality of life evaluated with SF-36 scale before and during treatment; hypolipidemic efficacy, compliance to therapy; adverse events and serious adverse events. Observation period was 6 months in all patients and 12 months in some patients at the discretion of the investigator.Results. 524 patients (79% men and 21% women completed the 6 months observation period and 116 patients were followed up for 12 months. Significant increase of all measures of SF-36 scales, physical and mental health was observed in 6 and 12 months of fluvastatin extended release treatment. Total and low density lipoprotein cholesterol reduction was 30.5% and 54.9% respectively, p<0.01, in 6 months and 34.2% and 34.3% respectively in 12 months of treatment, p<0.01. High density lipoprotein cholesterol was significantly increased by 22.5% in 12 months of treatment, p<0.01. There were very few adverse events and laboratory changes during the course of treatment.Conclusion. LESQOL study showed significant increase in quality of life and good hypolipidemic efficacy as well as good tolerability of fluvastatin extended release in patients after coronary angioplasty.

Use of a balloon-expandable metallic stent for treatment of nasopharyngeal stenosis in dogs and cats: six cases (2005-2007).

Science.gov (United States)

Berent, Allyson C; Weisse, Chick; Todd, Kimberly; Rondeau, Mark P; Reiter, Alexander M

2008-11-01

To determine outcome associated with use of a balloon-expandable metallic stent for treatment of nasopharyngeal stenosis in dogs and cats. Retrospective case series. 3 dogs and 3 cats. All 6 animals had severe inspiratory stertor at initial examination. Two animals had no orifice present at the stenosis. Nasopharyngeal stenosis was diagnosed and stent size determined by use of computed tomography. A percutaneous transluminal angioplasty balloon premounted with a balloon-expandable metallic stent was placed over a guidewire, advanced through the stenotic lesion under fluoroscopic and rhinoscopic guidance, and dilated to restore patency. All animals had immediate resolution of clinical signs after stent placement. The procedure took a median of 38 minutes (range, 22 to 70 minutes). One animal with a stenosis located far caudally needed the tip of the stent resected because of hairball entrapment and exaggerated swallowing. Both animals without an orifice in the stenosis had tissue in-growth requiring a covered stent. All animals were reexamined 6 to 12 weeks after treatment via rhinoscopy, radiography, computed tomography, or a combination of techniques. All animals lacked signs of discomfort; 5 of 6 were breathing normally 12 to 28 months after the procedure. Transnasal balloon-expandable metallic stent placement may represent a rapid, safe, noninvasive, and effective treatment in animals with nasopharyngeal stenosis. If the stenosis is extremely caudal in the nasopharynx, serial balloon dilatation might be considered prior to stent placement. A covered stent should be considered initially if the stenosis is completely closed.

Outcomes of Gonioscopy-assisted Transluminal Trabeculotomy (GATT) in Eyes With Prior Incisional Glaucoma Surgery.

Science.gov (United States)

Grover, Davinder S; Godfrey, David G; Smith, Oluwatosin; Shi, Wei; Feuer, William J; Fellman, Ronald L

2017-01-01

To report on outcomes of gonioscopy-assisted transluminal trabeculotomy (GATT) in eyes with prior incisional glaucoma surgery. A retrospective review was performed for all patients who underwent a GATT procedure with a history of prior incisional glaucoma surgery. Thirty-five eyes of 35 patients were treated. The mean age was 67.7 years. Nineteen eyes had a prior trabeculectomy, 13 eyes had a prior glaucoma drainage device, 4 eyes had a prior trabectome, and 5 eyes had prior endocyclophotocoagulation. Mean follow-up time was 22.7 months. For all eyes, the mean preoperative intraocular pressure (IOP) (SD) was 25.7 (6.5) mm Hg on 3.2 (1.0) glaucoma medications and at 24 months, the mean IOP (SD) was 15.4 (4.9) mm Hg on 2.0 (1.4) glaucoma medications (P<0.001). The prior trabeculectomy group had a preoperative IOP (SD) of 24.6 (6.4) mm Hg on 3.2 (1.0) medications and at month 24, the mean IOP (SD) was 16.7 (5.6) mm Hg on 2.1 (1.4) glaucoma medications. In the prior glaucoma drainage device group, the mean preoperative IOP (SD) was 27.0 (7.1) mm Hg on 3.4 (1.1) glaucoma medications and at 24 months, the mean IOP (SD) was 12.9 (2.6) mm Hg on 2.1 (1.2) glaucoma medications. At 24 months, the cumulative proportion of failure was 0.4 and the cumulative proportion of reoperation was 0.29. GATT appears to be safe and successful in treating 60% to 70% of open-angle patients with prior incisional glaucoma surgery. When considering all eyes, there was a significant decrease in IOP and required glaucoma medications at 24 months. This surgery should be considered in certain patients with open angles who have failed a primary traditional glaucoma surgery.

Percutaneous transluminal forceps biopsy in patients suspected of having malignant biliary obstruction: factors influencing the outcomes of 271 patients

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Park, Jung Gu; Jung, Gyoo-Sik; Yun, Jong Hyouk [Kosin University College of Medicine, Department of Radiology, Seo-gu, Busan (Korea, Republic of); Yun, Byung Chul; Lee, Sang Uk; Han, Byung Hoon [Kosin University College of Medicine, Department of Internal Medicine, Busan (Korea, Republic of); Ko, Ji Ho [Busan Medical Center, Department of Radiology, Busan (Korea, Republic of)

2017-10-15

To evaluate predictive factors for false-negative diagnosis of percutaneous forceps biopsies in patients suspected of having a malignant biliary obstruction Two hundred seventy one consecutive patients with obstructive jaundice underwent percutaneous forceps biopsy. In each patient, three to five specimens (mean, 3.5 specimens) were collected from the lesion. The final diagnosis for each patient was confirmed with pathologic findings at surgery, additional histocytologic data, or clinical and radiologic follow-up. Univariate and multivariate logistic regression analysis was used to identify risk factors associated with false-negative diagnosis. One hundred ninety four of 271 biopsies resulted in correct diagnoses of malignancy, while 20 biopsy diagnoses were proved to be true-negative. There were 57 false-negative diagnoses and no false-positive diagnoses. The diagnostic performance of transluminal forceps biopsy in malignant biliary obstructions was as follows: sensitivity, 77.2%; specificity, 100%; and accuracy, 78.9%; positive predictive value, 100%, negative predictive value; 25.9%. Periampullary segment of common bile duct, intrahepatic bile duct and metastatic disease were the significant risk factors of false-negative diagnosis. Percutaneous forceps biopsy provides relatively high accuracy in the diagnosis of malignant biliary obstructions. The predictive factors of false-negative biopsy were determined to be biopsy site and origin of primary tumour. (orig.)

The Use of Color-Coded Duplex Scanning in the Selection of Patients with Lower Extremity Arterial Disease for Percutaneous Transluminal Angioplasty: A Prospective Study

International Nuclear Information System (INIS)

Elsman, Bernard H.P.; Legemate, Dink A.; Heyden, Frank W.H.M. van der; Vos, Henk de; Mali, Willem P.T.M.; Eikelboom, Bert C.

1996-01-01

Purpose: To exploit the potential benefits of percutaneous transluminal angioplasty (PTA) in patients with short obstructive lesions in the lower extremity, it is preferable to select patients suitable for PTA before proceeding to hospital admission and angiography. The aim of this prospective study was to evaluate the role of color-coded duplex scanning in the correct selection of patients for PTA and its influence on planning the approach to the lesion. Methods: On the basis of clinical history, physical examination, pressure indices, and ultrasound duplex scanning, 109 patients were scheduled for PTA. Results: The indication for PTA was correct in 103 patients (94%), while the procedure was performed successfully in 98 patients (90%). The approach to the lesion was planned successfully in the majority of patients. Conclusion: This study shows that it is justifiable to plan PTA on the basis of information obtained by duplex scanning. Results of the duplex scan may guide the catheterization route

The predictive value of angiographic results for the outcome of percutaneous transluminal angioplasty in stenosed femoral bypass grafts

International Nuclear Information System (INIS)

Spijkerboer, Anje M.; Beek, Frederik J. A.; Graaf, Yolanda van der; Eikelboom, Bert C.; Mali, Willem P. T. M.

1997-01-01

Purpose. To assess the predictive value of immediate angiographic results after percutaneous transluminal angioplasty (PTA) for stenoses in femoral bypass grafts using duplex ultrasound (DUS) criteria. Methods. A 1-year follow-up with DUS was performed in 38 patients with 50 stenoses in 41 grafts, treated with PTA for a graft stenosis. The indication for PTA according to DUS criteria was a severe stenosis in 43 lesions, and a moderate stenosis in 7 lesions. In the moderate stenosis group 3 patients showed claudication and 1 patient had a nonhealing ulcer. For the purposes of statistical evaluation, primary patency was considered present if the graft was not occluded. The graft was considered to have failed when it was found to be occluded on DUS, or when secondary interventions (surgery, repeat PTA) were performed. Results. After 1 year the cumulative primary patency rate was 44$ [95% confidence interval (CI) 27.8-59.8]. Stenoses with initially good angiographic results after PTA (<30% residual stenosis) were 2.9 times more likely to be patent at 1 year than stenoses with initially poor or moderate angiographic results (hazard ratio 2.9, 95% CI 1.3-6.4,p=0.007). Conclusion. A poor or moderate angiographic result immediately following PTA was prognostic for poor long-term results and may indicate a requirement for earlier surgical intervention

Office hysteroscopic treatment of a vanishing external uterine orifice in a postmenopausal woman with an obstetrical history of 44 abortions

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Maurizio Guida

2015-11-01

Full Text Available Cervical stenosis, defined as cervical scarring of variable degree, represents a significant anatomical impediment to hysteroscopic procedures. Acquired cervical stenoses are more common than congenital forms and they are mainly associated with aging, estrogen–progesteron drugs, cervical trauma or carcinoma. The overcoming of cervical stenosis at office hysteroscopy is challenging and it often fails requiring the scheduling of the patient for an in-patient treatment under general anesthesia. We report the office hysteroscopy treatment of a vanishing external uterine orifice in a postmenopausal woman with an ultrasonographic report of a heterogeneous and thick endometrium suggestive of endometrial pathology, focusing on the main surgical steps to perform an adequate management.

Natural Orifice Translumenal Endoscopic Surgery for Anterior Spinal Procedures

OpenAIRE

Magno, Priscilla; Khashab, Mouen A.; Mas, Manuel; Giday, Samuel A.; Buscaglia, Jonathan M.; Shin, Eun Ji; Dray, Xavier; Kalloo, Anthony N.

2012-01-01

Background. NOTES techniques allow transesophageal access to the mediastinum. The aim of this study was to assess the feasibility of transesophageal biopsy of thoracic vertebrae. Methods. Nonsurvival experiments on four 50-kg porcine animals were performed. Transesophageal access to the mediastinum was attained using submucosal tunneling technique. Results. The posterior mediastinum was successfully accessed and navigated in all animals. Vertebral bodies and intervertebral spaces were easily ...

Could lymphatic mapping and sentinel node biopsy provide oncological providence for local resectional techniques for colon cancer? A review of the literature

Directory of Open Access Journals (Sweden)

Leroy Joel

2008-09-01

propriety for endoscopic resective techniques (including Natural Orifice Transluminal Endoscopic Surgery [NOTES] cannot be definitively answered at present. Study heterogeneity may account for the variability evident in the results from different centers. Enhanced capacity (perhaps to the level necessary to consider selective avoidance of en bloc mesenteric resection by its confinement to only early stage disease is plausible although not proven. Specific study of the technique in early stage tumors is clearly essential before proffering this approach.

Pressure-wire-guided percutaneous transluminal pulmonary angioplasty: a breakthrough in catheter-interventional therapy for chronic thromboembolic pulmonary hypertension.

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Inami, Takumi; Kataoka, Masaharu; Shimura, Nobuhiko; Ishiguro, Haruhisa; Yanagisawa, Ryoji; Fukuda, Keiichi; Yoshino, Hideaki; Satoh, Toru

2014-11-01

This study sought to prove the safety and effectiveness of pressure-wire-guided percutaneous transluminal pulmonary angioplasty (PTPA). PTPA has been demonstrated to be effective for treatment of chronic thromboembolic pulmonary hypertension. However, a major and occasionally fatal complication after PTPA is reperfusion pulmonary edema. To avoid this, we developed the PEPSI (Pulmonary Edema Predictive Scoring Index). The pressure wire has been used to detect insufficiency of flow in a vessel. We included 350 consecutive PTPA sessions in 103 patients with chronic thromboembolic pulmonary hypertension from January 1, 2009 to December 31, 2013. During these 5 years, 140 PTPA sessions were performed without guidance, 65 with guidance of PEPSI alone, and 145 with both PEPSI and pressure-wire guidance. Each PTPA session was finished after achieving PEPSI scores of PEPSI guidance and each target lesion achieving distal mean pulmonary arterial pressure PEPSI (0% and 6.9%, respectively). Furthermore, the group guided by pressure wire and PEPSI accomplished the same hemodynamic improvements with fewer numbers of target lesions treated and sessions performed. The combined approach using pressure wire and PEPSI produced more efficient clinical results and greatly reduced reperfusion pulmonary edema and vessel complications. This is further evidence that PTPA is an alternative strategy for treating chronic thromboembolic pulmonary hypertension. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Future of uniportal video-assisted thoracoscopic surgery-emerging technology.

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Li, Zheng; Ng, Calvin S H

2016-03-01

Uniportal VATS poses unique difficulties to the surgeon, mainly as a consequence of operating through a small single incision. The instruments in uniportal VATS have limited movement through the small incision. In addition, the approach to the surgical operating site is unidirectional, which may restrict vision and retraction, and unavoidably suffers from instrument fencing. Recent thoracoscopic technology in the form of a wide variable angled lens has to some extent improved these shortcomings. The development of an extendable flexible thoracoscope and wireless steerable endoscope (WSE) systems can further improve the visualization for surgery and reduce or even remove fencing between endoscope and instruments. New single incision access platforms both derived from Natural orifice transluminal endoscopic surgery (NOTES) and robotic surgery approaches are on the horizon. These may allow uniportal VATS to be performed through an even smaller ultra-minimally invasive incision, with improved vision, more freedom of movement of the instruments and greater precision. However, a number of problems remain to be resolved, including provision of a stable platform and payload, applied force limitations and equipment sterilization. Advances in uniportal VATS major lung resection techniques have not only challenged the surgeon to acquire new skills and knowledge, but at the same time have rekindled the collaborative spirit between industry and clinician in developing novel equipment and technology to push the boundaries of minimally invasive surgery. These technological improvements and innovations may improve operating efficiency and safety during uniportal VATS surgery.

Room air versus carbon dioxide pneumoperitoneum: effects on oxidative state, apoptosis and histology of splanchnic organs.

Science.gov (United States)

Ypsilantis, Petros; Lambropoulou, Maria; Tentes, Ioannis; Chryssidou, Maria; Georgantas, Themistoklis; Simopoulos, Constantinos

2016-04-01

Although CO2 is the insufflation gas of choice in laparoscopic procedures, room air is usually used in natural orifice transluminal endoscopic surgery. The aim of the present study was to compare the safety of room air versus CO2 pneumoperitoneum in terms of their effect on the oxidative state, apoptosis and tissue injury of splanchnic organs. Eighteen Wistar rats were assigned to three groups (n = 6 per group) and were subjected to 8 mm Hg room air (group Pne-Air) or CO2 pneumoperitoneum (group Pne-CO2) or sham operation for 60 min. Forty-five minutes postdeflation, tissue samples were excised from the liver, stomach, ileum and kidneys for reduced glutathione-to-glutathione disulfide (GSH/GSSG) ratio, caspase-8 and caspase-3 and hypoxia-inducible factor-1α (HIF-1α) immunohistochemical assessment and histopathologic examination. GSH/GSSG ratio substantially declined in both pneumoperitoneum groups. No change was noted in HIF-1α expression. Mild upregulation of caspase-8 and caspase-3 was noted in both pneumoperitoneum groups being less pronounced in group Pne-Air. Histopathologic score was increased in all organs studied, but the stomach, in both pneumoperitoneum groups. Pneumoperitoneum established by either room air or CO2 induced substantial oxidative stress, mild apoptosis and mild tissue injury in splanchnic organs. While air pneumoperitoneum conferred a less pronounced apoptotic effect, the oxidative state and histopathologic profile of splanchnic organs did not differ between insufflation gases.

Laparoscopic colorectal surgery: Current status and implementation of the latest technological innovations.

Science.gov (United States)

Pascual, Marta; Salvans, Silvia; Pera, Miguel

2016-01-14

The introduction of laparoscopy is an example of surgical innovation with a rapid implementation in many areas of surgery. A large number of controlled studies and meta-analyses have shown that laparoscopic colorectal surgery is associated with the same benefits than other minimally invasive procedures, including lesser pain, earlier recovery of bowel transit and shorter hospital stay. On the other hand, despite initial concerns about oncological safety, well-designed prospective randomized multicentre trials have demonstrated that oncological outcomes of laparoscopy and open surgery are similar. Although the use of laparoscopy in colorectal surgery has increased in recent years, the percentages of patients treated with surgery using minimally invasive techniques are still reduced and there are also substantial differences among centres. It has been argued that the limiting factor for the use of laparoscopic procedures is the number of surgeons with adequate skills to perform a laparoscopic colectomy rather than the tumour of patients' characteristics. In this regard, future efforts to increase the use of laparoscopic techniques in colorectal surgery will necessarily require more efforts in teaching surgeons. We here present a review of recent controversies of the use of laparoscopy in colorectal surgery, such as in rectal cancer operations, the possibility of reproducing complete mesocolon excision, and the benefits of intra-corporeal anastomosis after right hemicolectomy. We also describe the results of latest innovations such as single incision laparoscopic surgery, robotic surgery and natural orifice transluminal endoscopic surgery for colon and rectal diseases.

[Alternative approaches in thyroid surgery].

Science.gov (United States)

Maurer, E; Wächter, S; Bartsch, D K

2017-08-01

In thyroid surgery multiple different cervical minimally invasive (partly endoscopically assisted) and extracervical endoscopic (partly robot-assisted) approaches have been developed in the last 20 years. The aim of all these alternative approaches to the thyroid gland is optimization of the cosmetic result. The indications for the use of alternative and conventional approaches are principally the same. Important requirements for the use of alternative methods are nevertheless a broad experience in conventional thyroid operations of the thyroid and adequate patient selection under consideration of the size of the thyroid and the underlying pathology. Contraindications for the use of alternative approaches are a large size of the thyroid gland including local symptoms, advanced carcinomas, reoperations and previous radiations of the anterior neck. The current article gives an overview of the clinically implemented alternative approaches for thyroid surgery. Of those the majority must still be considered as experimental. The alternative approaches to the thyroid gland can be divided in cervical minimally invasive, extracervical endosopic (robot-assisted) and transoral operations (natural orifice transluminal endoscopic surgery, NOTES). Since conventional thyroid operations are standardized procedures with low complication rates, alternative approaches to the thyroid gland are considered critically in Germany. The request for a perfect cosmetic result should not overweigh patients' safety. Only a few alternative approaches (e. g. MIVAT, RAT) can yet be considered as a safe addition in experienced hands in highly selected patients.

Requirements of exercise myocardial scintigraphy (EMS) using Tl-201 prior and subsequent to coronary revascularisation, based on the example of transluminal angioplasty

International Nuclear Information System (INIS)

Maul, F.D.; Hoer, G.; Standke, R.; Kober, G.; Klepzig, H. Jr.; Doerr, G.; Baum, R.P.; Happ, J.; Kaltenbach, M.; Frankfurt Univ.

1985-01-01

Quantitative exercise myocardial scintigraphy (EMS) using Thallium-201 in planar technique was applied in 128 patients prior and subsequent to transluminal coronary angioplasty. The overall sensitivity was 92%, and 88% for multivessel disease. In contrast to previous reports, the sensitivity for lesions of the posterior wall proved not inferior to that for lesions of the anterior wall: RCA-stenoses 92%; LCX-stenoses 100% and RIA-stenoses 93%. The specificity was found to be 88%, and the accuracy 92%. Myocardial ischaemia, as detected by EMS and ex. ECG, amounted to 84% and 72%, respectively in single vessel disease. The degree of ischaemia, which was measured semiquantitatively in terms of score, paralleled that of stenosis. The accuracy for localisation of anterior or posterior wall lesions was 92%. In unsuccessfully treated patients the results were completely reproducible (100%) both in terms of the decision 'CAD yes or no', and regarding the localisation of a myocardial lesion. The reproducibility for detection of myocardial ischaemia was 82%. Conclusion: In comparison with SPECT the quantitative planar EMS procedure using Tl-201 is the method of choice for the detection and assessment of ischaemia prior and subsequent to revascularisation therapy. (orig.) [de

Does bladder outlet obstruction affect distance between the ureteric orifices in patients with benign prostate hyperplasia?

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Cüneyt Özden

2009-01-01

Full Text Available Objectives: Many morphological changes occur in the bladder due to bladder outlet obstruction (BOO in pa-tients with benign prostate hyperplasia (BPH. In the present study we evaluated the relationship between in-terureteric distance (IUD of the orifices and BOO in BPH patients.Materials and methods: Thirty-seven consecutive pa-tients with lower urinary tract symptoms at the urology polyclinic included in the study. Patients divided into 2 groups according to maximal flow rate (Qmax. The first group constituted of 18 patients with Qmax 15ml/s. The IUD measurement was performed with Doppler ultrasonography.Results: There was no significant difference between the groups regarding mean age and prostate volume. Mean IUD in the first group was 32.7±5.4 mm and mean IUD in the second group was 31.5±5.1 mm. There was no statistically significant difference between the groups regarding the IUD.Conclusions: Data obtained from the study revealed that measurement of IUD with Doppler ultrasonography not significantly related to BOO.

The Role of Duplex Scanning in the Selection of Patients with Critical Lower-Limb Ischemia for Infrainguinal Percutaneous Transluminal Angioplasty

International Nuclear Information System (INIS)

Loefberg, Anne-Marie; Karacagil, Sadettin; Hellberg, Anders; Bostroem, Annika; Ljungman, Christer; Ostholm, Goerel

2001-01-01

Purpose: To investigate the role of duplex scanning in the selection of patients with critical lower-limb ischemia (CLI) for infrainguinal percutaneous transluminal angioplasty (PTA).Methods: One hundred and sixty-two limbs with CLI (150 patients) that underwent duplex scanning within 3 months prior to conventional diagnostic angiography (n = 88) or infrainguinal PTA (n = 74) were retrospectively studied. The findings obtained from duplex scanning and angiography were analyzed in a masked fashion by two different investigators.Results: The accuracy, sensitivity, specificity, and negative and positive predictive values of duplex scanning in the selection of patients for infrainguinal PTA were 86%, 84%, 89%, 86%, and 87% respectively. Forty-two procedures (57%) were performed at multiple arterial segments. The accuracy of duplex scanning in the selection of femoropopliteal and crural lesions for PTA was over 85%. However, the sensitivity of duplex scanning in the selection of popliteal and crural lesions for PTA was 49% and 38% respectively, compared with 80% for superior femoral artery lesions. In 39% of patients who were correctly selected for PTA, duplex scanning misdiagnosed one of the multiple lesions treated by PTA.Conclusion: Duplex scanning can safely be used for the selection of patients for infrainguinal PTA. The sensitivity of duplex scanning in the selection of lesions for PTA was less satisfactory in the popliteal and crural arteries compared with the femoropopliteal arteries

Urethral orifice hyaluronic acid injections: a novel animal model of bladder outlet obstruction.

Science.gov (United States)

Wang, Yongquan; Xiong, Zhiyong; Gong, Wei; Zhou, Zhansong; Lu, Gensheng

2015-02-21

We produced a novel model of bladder outlet obstruction (BOO) by periurethral injection of hyaluronic acid and compared the cystometric features, postoperative complications, and histopathological changes of that model with that of traditional open surgery. Forty female Sprague-Dawley rats were divided into three groups. Fifteen rats were subcutaneously injected with 0.2 ml hyaluronic acid at 5, 7, and 12 o'clock around the urethral orifice. Another fifteen rats underwent traditional open partial proximal urethral obstruction surgery, and 10 normal rats used as controls. After 4 weeks, filling cystometry, postoperative complications, and histopathological features were evaluated in each group. Three rats were also observed for 12 weeks after hyaluronic acid injection to evaluate the long-term effect. Hyaluronic acid periurethral injection caused increased maximum cystometric capacity, maximum bladder pressure, micturition interval, and post-void residual urine volume compared with control (p injection group had significantly shorter operative time, less incidence of incision infection and bladder stone formation compared with the surgery group (p injection and surgery bladders; these were not observed in the control group. Bladder weight and thickness of smooth muscle in the injection and surgery groups were significantly greater than those in the control group (p injection or control groups. Rats periurethrally injected hyaluronic acid were stable the compound was not fully absorbed in any rat after 12 weeks. Hyaluronic acid periurethral injection generates a simple, effective, and persistent animal model of BOO with lower complications, compared with traditional surgery.

Prediction of flow rates through an orifice at pressures corresponding to the transition between molecular and isentropic flow

International Nuclear Information System (INIS)

DeMuth, S.F.; Watson, J.S.

1985-01-01

A model of compressible flow through an orifice, in the region of transition from free molecular to isentropic expansion flow, has been developed and tested for accuracy. The transitional or slip regime is defined as the conditions where molecular interactions are too many for free molecular flow modeling, yet not great enough for isentropic expansion flow modeling. Due to a lack of literature establishing a well-accepted model for predicting transitional flow, it was felt such work would be beneficial. The model is nonlinear and cannot be satisfactorily linearized for a linear regression analysis. Consequently, a computer routine was developed which minimized the sum of the squares of the residual flow for the nonlinear model. The results indicate an average accuracy within 15% of the measured flow throughout the range of test conditions. Furthermore, the results of the regression analysis indicate that the transitional regime lies between Knudsen numbers of approximately 2 and 45. 4 refs., 3 figs., 1 tab

Neointimal Hyperplasia after Silverhawk Atherectomy versus Percutaneous Transluminal Angioplasty (PTA) in Femoropopliteal Stent Reobstructions: A Controlled, Randomized Pilot Trial

International Nuclear Information System (INIS)

Brodmann, Marianne; Rief, Peter; Froehlich, Harald; Dorr, Andreas; Gary, Thomas; Eller, Philipp; Hafner, Franz; Deutschmann, Hannes; Seinost, Gerald; Pilger, Ernst

2013-01-01

Due to intimal hyperplasia instent reobstruction in the femoropopliteal arterial segment is still an unsolved problem. Different techniques have been discussed in case of reintervention to guarantee longlasting patency rate. We conducted a randomized, controlled, pilot trial comparing Silverhawk atherectomy with percutaneous transluminal angioplasty (PTA) in patients with a first instent reobstruction in the femoropopliteal arterial segment, to evaluate intima media thickness (IMT) within the treated segment, as a parameter of recurrence of intimal hyperplasia. In a total 19 patients were included: 9 patients in the atherectomy device and 10 patients in the PTA arm. IMT within the treated segment was statistically significantly elevated in all patients treated with the Silverhawk device versus the patients treated with PTA. The obvious differentiation in elevation of IMT in nonfavor for patients treated with the Silverhawk device started at month 2 (max IMT SH 0.178 mm vs. IMT PTA 0.1 mm, p = 0.001) with a spike at month 5 (max IMT SH 0.206 mm vs. IMT PTA 0.145 mm, p = 0.003) and a decline once again at month 6 (max IMT SH 0.177 mm vs. IMT PTA 0.121 mm, p = 0.02). The values for mean IMT performed the same way. Although Silverhawk atherectomy provides good results at first sight, in the midterm follow-up of treatment of first instent restenosis it did not perform better than PTA as it showed elevated reoccurrence of intimal media hyperplasia.

Neointimal Hyperplasia after Silverhawk Atherectomy versus Percutaneous Transluminal Angioplasty (PTA) in Femoropopliteal Stent Reobstructions: A Controlled, Randomized Pilot Trial

Energy Technology Data Exchange (ETDEWEB)

Brodmann, Marianne, E-mail: marianne.brodmann@medunigraz.at; Rief, Peter; Froehlich, Harald; Dorr, Andreas; Gary, Thomas; Eller, Philipp; Hafner, Franz [Medical University of Graz, Division of Angiology (Austria); Deutschmann, Hannes [Medical University Graz, Division of Interventional Radiology (Austria); Seinost, Gerald; Pilger, Ernst [Medical University of Graz, Division of Angiology (Austria)

2013-02-15

Due to intimal hyperplasia instent reobstruction in the femoropopliteal arterial segment is still an unsolved problem. Different techniques have been discussed in case of reintervention to guarantee longlasting patency rate. We conducted a randomized, controlled, pilot trial comparing Silverhawk atherectomy with percutaneous transluminal angioplasty (PTA) in patients with a first instent reobstruction in the femoropopliteal arterial segment, to evaluate intima media thickness (IMT) within the treated segment, as a parameter of recurrence of intimal hyperplasia. In a total 19 patients were included: 9 patients in the atherectomy device and 10 patients in the PTA arm. IMT within the treated segment was statistically significantly elevated in all patients treated with the Silverhawk device versus the patients treated with PTA. The obvious differentiation in elevation of IMT in nonfavor for patients treated with the Silverhawk device started at month 2 (max IMT SH 0.178 mm vs. IMT PTA 0.1 mm, p = 0.001) with a spike at month 5 (max IMT SH 0.206 mm vs. IMT PTA 0.145 mm, p = 0.003) and a decline once again at month 6 (max IMT SH 0.177 mm vs. IMT PTA 0.121 mm, p = 0.02). The values for mean IMT performed the same way. Although Silverhawk atherectomy provides good results at first sight, in the midterm follow-up of treatment of first instent restenosis it did not perform better than PTA as it showed elevated reoccurrence of intimal media hyperplasia.

A three-dimensional semi-analytical solution for predicting drug release through the orifice of a spherical device.

Science.gov (United States)

Simon, Laurent; Ospina, Juan

2016-07-25

Three-dimensional solute transport was investigated for a spherical device with a release hole. The governing equation was derived using the Fick's second law. A mixed Neumann-Dirichlet condition was imposed at the boundary to represent diffusion through a small region on the surface of the device. The cumulative percentage of drug released was calculated in the Laplace domain and represented by the first term of an infinite series of Legendre and modified Bessel functions of the first kind. Application of the Zakian algorithm yielded the time-domain closed-form expression. The first-order solution closely matched a numerical solution generated by Mathematica(®). The proposed method allowed computation of the characteristic time. A larger surface pore resulted in a smaller effective time constant. The agreement between the numerical solution and the semi-analytical method improved noticeably as the size of the orifice increased. It took four time constants for the device to release approximately ninety-eight of its drug content. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigation on Hydrodynamic Cavitation of a Restriction Orifice and Static Mixer on Crud-like Deposits

International Nuclear Information System (INIS)

Kim, Seong Man; Lee, Seung Won; Park, Seong Dae; Kang, Sa Rah; Seo, Han; Bang, In Cheol

2012-01-01

Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core have shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice and static mixer fundamentally

Investigation on Hydrodynamic Cavitation of a Restriction Orifice and Static Mixer on Crud-like Deposits

Energy Technology Data Exchange (ETDEWEB)

Kim, Seong Man; Lee, Seung Won; Park, Seong Dae; Kang, Sa Rah; Seo, Han; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2012-05-15

Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core have shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice and static mixer fundamentally

Experimental study of mixed convection flow through a horizontal orifice or vent linking two compartments

International Nuclear Information System (INIS)

Varrall, Kevin

2016-01-01

To answer building issues and fire safety challenges, this thesis deals with the mixed convection flow through a horizontal orifice or vent linking two compartments. The aim is to improve the understanding and the modeling of the exchange of gas through the opening. A small scale experimental study and a theoretical approach are proposed. The study focuses first on the influence of the geometrical ratio L/D of the opening on the flow rate at the vent for free convection regime. Non-intrusive measurements, via the tracking of the interface between two non miscible liquids in an isothermal approach, and thanks to the SPIV in a thermal approach, permit to describe the bidirectional exchange process and to consolidate existing correlations. Experiments for mixed convection regime aim to study the impact of mechanical ventilation (in blowing and extracting modes) on the exchanged flow rates. The comparison between existing correlations and experimental data shows large differences. A modification of the correlation of Cooper is proposed. A theoretical approach from the simplified Navier Stokes equations and with the Boussinesq approximation permits to discuss the construction of existing correlations. From this theory, a more accurate model than those available in the literature is proposed thanks to an adjustment of discharge coefficients from experimental data. (author)

Transcutaneous oximetry compared to ankle-brachial-index measurement in the evaluation of percutaneous transluminal angioplasty

International Nuclear Information System (INIS)

Wildgruber, Moritz; Wolf, Oliver; Weiss, Wolfgang; Berger, Hermann; Lutzenberger, Werner; Eckstein, Hans-Henning; Heider, Peter

2007-01-01

Objective: To investigate transcutaneous oximetry as parameter of the microcirculation is correlated to ankle-brachial-index as parameter of the macrocirculation after peripheral angioplasty procedures. Design: Prospective study. Materials and methods: 60 patients suffering from intermittent claudication were scheduled for angioplasty treatment. 45 patients were considered as eligible for angioplasty after angiographic evaluation, 15 patients underwent angiography only. Transcutaneous oximetry measurements were performed before the procedure, at the end of intervention, 24 h as well as 2 and 4 weeks after percutaneous transluminal angioplasty. Ankle-brachial-indices were obtained before intervention, 24 h as well as 2 and 4 weeks later. Results: Ankle-brachial-indices increased significantly at 24 h after angioplasty in patients being treated with angioplasty. Transcutaneous oximetry values dropped significantly at the end of the procedure and returned close to the baseline levels at 2 and 4 weeks after angioplasty. Ankle-brachial-indices and transcutaneous oximetry were positively correlated before (r = 0.3833, p = 0.009) as well as 4 weeks after angioplasty (r = 0.4596, p = 0.001). Immediately after radiological interventions, ankle-brachial-indices and transcutaneous oximetry are not positively correlated. In patients undergoing angiography only, transcutaneous oximetry levels drop significantly immediately after angiography and remain at decreased levels even at 4 weeks after intervention. Conclusion: Transcutaneous oximetry as parameter of the microcirculation is positively correlated with ankle-brachial-index as parameter of the macrocirculation before and at 4 weeks after angioplasty. Intraarterial angiography leads to a sudden decrease in skin microcirculation without affecting macrocirculation. As indicated by a lack of recovery in transcutaneous oximetry levels after 4 weeks, angiography alone results in a prolonged impaired microcirculation which may

Natural Modes of Multi-Orifice Bubbling from a Common Plenum

Czech Academy of Sciences Publication Activity Database

Růžička, Marek; Drahoš, Jiří; Zahradník, Jindřich; Thomas, N. H.

1999-01-01

Roč. 54, č. 21 (1999), s. 5223-5229 ISSN 0009-2509 R&D Projects: GA AV ČR KSK2040602 Grant - others:CEC(XE) INCO-COPERNICUS:ERB IC15-CT98-0904 Institutional research plan: CEZ:AV0Z4072921 Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.218, year: 1999

Gonioscopy-assisted transluminal trabeculotomy, ab interno trabeculotomy: technique report and preliminary results.

Science.gov (United States)

Grover, Davinder S; Godfrey, David G; Smith, Oluwatosin; Feuer, William J; Montes de Oca, Ildamaris; Fellman, Ronald L

2014-04-01

To introduce a minimally invasive, ab interno approach to a circumferential 360-degree trabeculotomy and to report the preliminary results. Retrospective, noncomparative cases series. Eighty-five eyes of 85 consecutive patients who sought treatment at Glaucoma Associates of Texas with uncontrolled open-angle glaucoma and underwent gonioscopy-assisted transluminal trabeculotomy (GATT) for whom there was at least 6 months of follow-up data. Retrospective chart review of patients who underwent GATT by 4 of the authors (D.S.G., D.G.G., O.S., R.L.F.) between October 2011 and October 2012. The surgery was performed in adults with various open-angle glaucomas. Intraocular pressure (IOP), glaucoma medications, visual acuity, and intraoperative as well as postoperative complications. Eighty-five patients with an age range of 24 to 88 years underwent GATT with at least 6 months of follow-up. In 57 patients with primary open-angle glaucoma, the IOP decreased by 7.7 mmHg (standard deviation [SD], 6.2 mm Hg; 30.0% [SD, 22.7%]) with an average decrease in glaucoma medications of 0.9 (SD, 1.3) at 6 months. In this group, the IOP decreased by 11.1 mmHg (SD, 6.1 mmHg; 39.8% [SD, 16.0%]) with 1.1 fewer glaucoma medications at 12 months. In the secondary glaucoma group of 28 patients, IOP decreased by 17.2 mmHg (SD, 10.8 mmHg; 52.7% [SD, 15.8%]) with an average of 2.2 fewer glaucoma medications at 6 months. In this group, the IOP decreased by 19.9 mmHg (SD, 10.2 mmHg; 56.8% [SD, 17.4%]) with an average of 1.9 fewer medications (SD, 2.1) at 12 months. Treatment was considered to have failed in 9% (8/85) of patients because of the need for further glaucoma surgery. The cumulative proportion of failure at 1 year ranged from 0.1 to 0.32, depending on the group. Lens status or concurrent cataract surgery did not have a statistically significant effect on IOP in eyes that underwent GATT at either 6 or 12 months (P > 0.35). The most common complication was transient hyphema, seen in

Comparing Percutaneous Transluminal Angioplasty and Stent Placement for Treatment of Subclavian Arterial Occlusive Disease: A Systematic Review and Meta-Analysis

International Nuclear Information System (INIS)

Ahmed, Ahmed T.; Mohammed, Khaled; Chehab, Monzer; Brinjikji, Waleed; Hassan Murad, M.; Cloft, Harry; Bjarnason, Haraldur

2016-01-01

Background and PurposeSubclavian artery occlusive disease (SAOD) is often associated with cerebrovascular symptoms such as subclavian steal syndrome and stroke. We conducted a systematic review and meta-analysis to compare percutaneous transluminal angioplasty (PTA) and stent placement for the treatment of SAOD.Materials and MethodsWe searched Medline, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus through October 16, 2014. From each study, we abstracted baseline patient characteristics, study design variables, and outcome data including rates of technical success, primary patency (≤2 and >2 years follow-up), symptom resolution, and complications. Meta-analysis was performed using a random-effects model.ResultsA total of 35 non-comparative studies with 1726 patients were included. Technical success rate was significantly higher in the stent group than the PTA group (92.8 vs 86.8 %, p = 0.007). Long-term primary patency rates (76.9 vs 79.6 %, p = 0.729) and symptom resolution rates (82.2 vs 73.0 %, p = 0.327) were not statistically different. There was no statistically significant difference in the rates of stroke or death.ConclusionStent placement for treatment of SAOD may be associated with higher rates of technical success but similar rates of symptom resolution and long-term outcomes. The confidence in the available estimates is low. Further comparative studies are needed to guide patients and clinicians in shared decision making.

Comparing Percutaneous Transluminal Angioplasty and Stent Placement for Treatment of Subclavian Arterial Occlusive Disease: A Systematic Review and Meta-Analysis

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Ahmed T., E-mail: Ahmed.Ahmed1@mayo.edu; Mohammed, Khaled, E-mail: Mohammed.Khaled@mayo.edu [Mayo Clinic, Evidence-Based Practice Research Program (United States); Chehab, Monzer, E-mail: moe.chehab@beumont.edu [Oakland University William Beaumont School of Medicine, Department of Diagnostic Radiology and Molecular Imaging (United States); Brinjikji, Waleed, E-mail: Brinjikji.Waleed@mayo.edu [Mayo Clinic, Department of Radiology (United States); Hassan Murad, M., E-mail: Murad.Mohammad@mayo.edu [Mayo Clinic, Evidence-Based Practice Research Program (United States); Cloft, Harry, E-mail: Cloft.Harry@mayo.edu; Bjarnason, Haraldur, E-mail: Bjarnason.Haraldur@mayo.edu [Mayo Clinic, Department of Radiology (United States)

2016-05-15

Background and PurposeSubclavian artery occlusive disease (SAOD) is often associated with cerebrovascular symptoms such as subclavian steal syndrome and stroke. We conducted a systematic review and meta-analysis to compare percutaneous transluminal angioplasty (PTA) and stent placement for the treatment of SAOD.Materials and MethodsWe searched Medline, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus through October 16, 2014. From each study, we abstracted baseline patient characteristics, study design variables, and outcome data including rates of technical success, primary patency (≤2 and >2 years follow-up), symptom resolution, and complications. Meta-analysis was performed using a random-effects model.ResultsA total of 35 non-comparative studies with 1726 patients were included. Technical success rate was significantly higher in the stent group than the PTA group (92.8 vs 86.8 %, p = 0.007). Long-term primary patency rates (76.9 vs 79.6 %, p = 0.729) and symptom resolution rates (82.2 vs 73.0 %, p = 0.327) were not statistically different. There was no statistically significant difference in the rates of stroke or death.ConclusionStent placement for treatment of SAOD may be associated with higher rates of technical success but similar rates of symptom resolution and long-term outcomes. The confidence in the available estimates is low. Further comparative studies are needed to guide patients and clinicians in shared decision making.

ESBWR enhanced flow distribution with optimized orificing and related fuel cycle performance

Energy Technology Data Exchange (ETDEWEB)

Pearson, G. J.; Karve, A. A.; Fawcett, R. M. [Global Nuclear Fuel - America, 3901 Castle Hayne Road, Wilmington, NC 28401 (United States)

2012-07-01

The Economic Simplified Boiling Water Reactor (ESBWR) is GEH's latest Generation III+ reactor design with natural circulation coolant flow and passive safety features. Reliance on natural circulation as the sole means of core coolant driving force results in increased power-to-flow ratio and places increased importance on the efficient distribution of core flow in order to achieve optimum thermal margins and improved fuel cycle efficiency. In addition, the large core size of the ESBWR, containing 1132 bundles, greatly benefits from a more targeted distribution of flow, directing a higher fraction of flow to high power bundles in the 'ring of fire' region of typical BWR loading patterns and a lower fraction of flow to low power bundles on and near the core periphery. Desirable flow distributions can be achieved by modifying the hydraulic resistance of the inlet orifices to preferentially force flow to the targeted region. The inlet orifice is a feature that is incorporated into the fuel support piece of a typical BWR design. The majority of existing forced circulation BWR's rely on only two orifice types - a peripheral orifice located along the outermost row and a central orifice in all other locations. A more optimum distribution of core flow is achievable with the introduction of multiple inlet orifice types. Multi-zone orifice layouts comprised of two, three and four types have been evaluated for the ESBWR. An efficient radial distribution of flow can have a direct beneficial effect on the Minimum Critical Power Ratio (MCPR). An improved multi-zone orifice layout in the ESBWR has the potential of significantly increasing active flow in high power bundles. On average, this flow increase corresponds to a noteworthy MCPR improvement. Additional MCPR margin may be used to enhance operating flexibility and to achieve reduced fuel cycle costs over the plant lifetime. Combined with GNF's latest high performance fuel design for the ESBWR, GNF2E

ESBWR enhanced flow distribution with optimized orificing and related fuel cycle performance

International Nuclear Information System (INIS)

Pearson, G. J.; Karve, A. A.; Fawcett, R. M.

2012-01-01

The Economic Simplified Boiling Water Reactor (ESBWR) is GEH's latest Generation III+ reactor design with natural circulation coolant flow and passive safety features. Reliance on natural circulation as the sole means of core coolant driving force results in increased power-to-flow ratio and places increased importance on the efficient distribution of core flow in order to achieve optimum thermal margins and improved fuel cycle efficiency. In addition, the large core size of the ESBWR, containing 1132 bundles, greatly benefits from a more targeted distribution of flow, directing a higher fraction of flow to high power bundles in the 'ring of fire' region of typical BWR loading patterns and a lower fraction of flow to low power bundles on and near the core periphery. Desirable flow distributions can be achieved by modifying the hydraulic resistance of the inlet orifices to preferentially force flow to the targeted region. The inlet orifice is a feature that is incorporated into the fuel support piece of a typical BWR design. The majority of existing forced circulation BWR's rely on only two orifice types - a peripheral orifice located along the outermost row and a central orifice in all other locations. A more optimum distribution of core flow is achievable with the introduction of multiple inlet orifice types. Multi-zone orifice layouts comprised of two, three and four types have been evaluated for the ESBWR. An efficient radial distribution of flow can have a direct beneficial effect on the Minimum Critical Power Ratio (MCPR). An improved multi-zone orifice layout in the ESBWR has the potential of significantly increasing active flow in high power bundles. On average, this flow increase corresponds to a noteworthy MCPR improvement. Additional MCPR margin may be used to enhance operating flexibility and to achieve reduced fuel cycle costs over the plant lifetime. Combined with GNF's latest high performance fuel design for the ESBWR, GNF2E, and improved loading

Efficacy of percutaneous transluminal renal angioplasty with stent in elderly male patients with atherosclerotic renal artery stenosis

Directory of Open Access Journals (Sweden)

Zhao J

2012-10-01

Full Text Available Jiahui Zhao, Qingli Cheng, Xiaoying Zhang, Meihua Li, Sheng Liu, Xiaodan WangDepartment of Geriatric Nephrology, Chinese PLA General Hospital, Beijing, ChinaObjectives: Percutaneous transluminal renal angioplasty with stent implantation (PTRAS has become the treatment of choice for atherosclerotic renal artery stenosis (ARAS. This study evaluates the long-term effects of PTRAS on hypertension and renal function in elderly patients with ARAS.Methods: We conducted a retrospective cohort study of all patients who underwent PTRAS in the geriatric division of a tertiary medical center during the period 2003–2010. The clinical data were extracted from the medical records of each patient. Changes in blood pressure, antihypertensive treatment, and estimated glomerular filtration rate were analyzed before and after PTRAS.Results: Eighty-six stents in 81 elderly patients were placed successfully. The average age of the patients was 76.2 years (65–89 years. Mean follow-up was 31.3 months (range 12 –49 months. There was a significant decrease in both systolic and diastolic blood pressure at the third day after the PTRAS procedure and the reduction in blood pressure was constant throughout the follow-up period until 36 months after PTRAS. However, there was no marked benefit to renal function outcome during the follow-up period. The incidence of contrast-induced nephropathy was 9.9% in this study group. The rate of renal artery restenosis was 14.8%. The survival rate was 96.3% for 4 years after the procedure.Conclusion: It is beneficial to control blood pressure in elderly patients with ARAS up to 36 months after a PTRAS procedure. However, their renal function improvement is limited.Keywords: angioplasty, hypertension, renal function, elderly, renal artery stenosis

Flow motion waves with high and low frequency in severe ischaemia before and after percutaneous transluminal angioplasty.

Science.gov (United States)

Hoffmann, U; Schneider, E; Bollinger, A

1990-09-01

STUDY OF OBJECTIVE: The aim was to evaluate skin flux and prevalence of low and high frequency flow motion waves in patients with severe ischaemia due to peripheral arterial occlusive disease before and after percutaneous transluminal angioplasty (PTA) with and without local thrombolysis. Flow motion was recorded by the laser Doppler technique at the dorsum of the foot before, one day, and one month after PTA. The results were separately analysed in patients with successful and unsuccessful treatment. 18 patients with rest pain or incipient gangrene were included. Mean pretreatment systolic ankle pressure was 55.8(SD 25.5) mm Hg, and mean transcutaneous PO2 at 43 degrees C was 5.2(9.4) mm Hg. Arteriography revealed relevant stenoses or occlusions of the femoropopliteal and calf arteries. Before treatment two patterns of flow motion with characteristic frequency ranges were observed at the foot dorsum and at a probe temperature of 32 degrees C: low frequency (LF) waves with a mean frequency of 2.2(0.5) cycles.min-1 and a mean amplitude of 0.73(0.42) arbitrary units (AU) and high frequency (HF) waves with a mean frequency of 22.6(4.2) cycles.min-1 and a mean amplitude of 0.39(0.33) AU. PTA was successful in 11 of the 18 patients. After successful treatment, prevalence of HF waves decreased from 10/11 to 4/11 cases (p less than 0.001), but remained nearly unchanged after failed procedure. Prevalence of LF waves before and after PTA did not differ significantly. Our data support the hypothesis that HF waves represent a reaction of skin microcirculation to severe ischaemia. With reference to animal studies it is proposed that HF waves originate from terminal arterioles. They may function as a compensatory mechanism of flow regulation involved in pathophysiology of ischaemia.

Stability of multilead ST-segment "fingerprints" over time after percutaneous transluminal coronary angioplasty and its usefulness in detecting reocclusion.

Science.gov (United States)

Krucoff, M W; Parente, A R; Bottner, R K; Renzi, R H; Stark, K S; Shugoll, R A; Ahmed, S W; DeMichele, J; Stroming, S L; Green, C E

1988-06-01

Multilead ST-segment recordings taken during percutaneous transluminal coronary angioplasty (PTCA) could function as an individualized noninvasive template or "fingerprint," useful in evaluating transient ischemic episodes after leaving the catheterization laboratory. To evaluate the reproducibility of such ST-segment patterns over time, these changes were analyzed in patients grouped according to the time between occlusion and reocclusion. For the patients in group 1, the study required comparing their "fingerprints" in repeat balloon inflation during PTCA (reocclusion in less than 1 hour), for those in group 2, comparing ST "fingerprints" during PTCA with ST changes during spontaneous early myocardial infarction (reocclusion in 24 hours) and in group 3, comparing ST "fingerprints" with ST changes during repeat PTCA for restenosis greater than 1 month after the initial PTCA. The ST "fingerprints" among the 20 patients in group 1 were identical in 14 cases (70%) and clearly related in another 4 (20%). Of the 23 patients in group 2, 12 (52%) had the same and 8 (35%) had related patterns. Of 19 patients in group 3, 8 (42% had the same pattern and 8 (42%) had related patterns. Thus, ST fingerprints were the same or clearly related with reocclusion in the same patient from less than 1 hour to greater than 1 month after initial occlusion in 87% of patients overall, in 90% in less than 1 hour, in 87% in less than 24 hours and in 84% greater than 1 month later. Multilead pattern ST-segment "fingerprints" may serve as a noninvasive marker for detecting site-specific reocclusion.

Neointimal hyperplasia after silverhawk atherectomy versus percutaneous transluminal angioplasty (PTA) in femoropopliteal stent reobstructions: a controlled, randomized pilot trial.

Science.gov (United States)

Brodmann, Marianne; Rief, Peter; Froehlich, Harald; Dorr, Andreas; Gary, Thomas; Eller, Philipp; Hafner, Franz; Deutschmann, Hannes; Seinost, Gerald; Pilger, Ernst

2013-02-01

Due to intimal hyperplasia instent reobstruction in the femoropopliteal arterial segment is still an unsolved problem. Different techniques have been discussed in case of reintervention to guarantee longlasting patency rate. We conducted a randomized, controlled, pilot trial comparing Silverhawk atherectomy with percutaneous transluminal angioplasty (PTA) in patients with a first instent reobstruction in the femoropopliteal arterial segment, to evaluate intima media thickness (IMT) within the treated segment, as a parameter of recurrence of intimal hyperplasia. In a total 19 patients were included: 9 patients in the atherectomy device and 10 patients in the PTA arm. IMT within the treated segment was statistically significantly elevated in all patients treated with the Silverhawk device versus the patients treated with PTA. The obvious differentiation in elevation of IMT in nonfavor for patients treated with the Silverhawk device started at month 2 (max IMT SH 0.178 mm vs. IMT PTA 0.1 mm, p = 0.001) with a spike at month 5 (max IMT SH 0.206 mm vs. IMT PTA 0.145 mm, p = 0.003) and a decline once again at month 6 (max IMT SH 0.177 mm vs. IMT PTA 0.121 mm, p = 0.02). The values for mean IMT performed the same way. Although Silverhawk atherectomy provides good results at first sight, in the midterm follow-up of treatment of first instent restenosis it did not perform better than PTA as it showed elevated reoccurrence of intimal media hyperplasia.

Assessment of myocardial bridge by cardiac CT: Intracoronary transluminal attenuation gradient derived from diastolic phase predicts systolic compression

Energy Technology Data Exchange (ETDEWEB)

Yu, Meng Meng; Zhang, Yang; Li, Yue Hua; Li, Wen Bin; Li, Ming Hua; Zhang, Jiayin [Institute of Diagnostic and Interventional Radiology, Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, Shangha (China)

2017-08-01

To study the predictive value of transluminal attenuation gradient (TAG) derived from diastolic phase of coronary computed tomography angiography (CCTA) for identifying systolic compression of myocardial bridge (MB). Consecutive patients diagnosed with MB based on CCTA findings and without obstructive coronary artery disease were retrospectively enrolled. In total, 143 patients with 144 MBs were included in the study. Patients were classified into three groups: without systolic compression, with systolic compression < 50%, and with systolic compression ≥ 50%. TAG was defined as the linear regression coefficient between intraluminal attenuation in Hounsfield units (HU) and length from the vessel ostium. Other indices such as the length and depth of the MB were also recorded. TAG was the lowest in MB patients with systolic compression ≥ 50% (-19.9 ± 8.7 HU/10 mm). Receiver operating characteristic curve analysis was performed to determine the optimal cutoff values for identifying systolic compression ≥ 50%. The result indicated an optimal cutoff value of TAG as -18.8 HU/10 mm (area under curve = 0.778, p < 0.001), which yielded higher sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy (54.1, 80.5, 72.8, and 75.0%, respectively). In addition, the TAG of MB with diastolic compression was significantly lower than the TAG of MB without diastolic compression (-21.4 ± 4.8 HU/10 mm vs. -12.7 ± 8 HU/10 mm, p < 0.001). TAG was a better predictor of MB with systolic compression ≥ 50%, compared to the length or depth of the MB. The TAG of MB with persistent diastolic compression was significantly lower than the TAG without diastolic compression.

Current status of core and advanced adult gastrointestinal endoscopy training in Canada: Survey of existing accredited programs.

Science.gov (United States)

Xiong, Xin; Barkun, Alan N; Waschke, Kevin; Martel, Myriam

2013-01-01

To determine the current status of core and advanced adult gastroenterology training in Canada. A survey consisting of 20 questions pertaining to core and advanced endoscopy training was circulated to 14 accredited adult gastroenterology residency program directors. For continuous variables, median and range were analyzed; for categorical variables, percentage and associated 95% CIs were analyzed. All 14 programs responded to the survey. The median number of core trainees was six (range four to 16). The median (range) procedural volumes for gastroscopy, colonoscopy, percutaneous endoscopic gastrostomy and sigmoidoscopy, respectively, were 400 (150 to 1000), 325 (200 to 1500), 15 (zero to 250) and 60 (25 to 300). Eleven of 13 (84.6%) programs used endoscopy simulators in their curriculum. Eight of 14 programs (57%) provided a structured advanced endoscopy training fellowship. The majority (88%) offered training of combined endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasonography. The median number of positions offered yearly for advanced endoscopy fellowship was one (range one to three). The median (range) procedural volumes for ERCP, endoscopic ultrasonography and endoscopic mucosal resection, respectively, were 325 (200 to 750), 250 (80 to 400) and 20 (10 to 63). None of the current programs offered training in endoscopic submucosal dissection or natural orifice transluminal endoscopic surgery. Most accredited adult Canadian gastroenterology programs met the minimal procedural requirements recommended by the Canadian Association of Gastroenterology during core training. However, a more heterogeneous experience has been observed for advanced training. Additional studies would be required to validate and standardize evaluation tools used during gastroenterology curricula.

Diagnosis and management of esophageal achalasia.

Science.gov (United States)

Stavropoulos, Stavros N; Friedel, David; Modayil, Rani; Parkman, Henry P

2016-09-13

Achalasia is a rare esophageal motility disorder that is usually idiopathic in origin. It is characterized by dysphagia, and patients often have chest pain, regurgitation, weight loss, and an abnormal barium radiograph showing esophageal dilation with narrowing at the gastroesophageal junction. Abnormal or absent esophageal peristalsis and impaired relaxation of the lower esophageal sphincter (LES) are typically seen on esophageal manometry. The advent of high resolution manometry (HRM) has allowed more precise diagnosis of achalasia, subtype designation, and differentiation from other esophageal motor disorders with an initial seminal publication in 2008 followed by further refinements of what has been termed the Chicago classification. Potential treatments include drugs, endoscopic botulinum toxin injection, balloon dilation, traditional surgery (usually laparoscopic Heller myotomy; LHM), and a novel, less invasive, natural orifice transluminal endoscopic surgery (NOTES) approach to Heller myotomy termed peroral endoscopic myotomy (POEM). The first human POEM was performed in 2008, with the first publication appearing in 2010 and evidence now rapidly accumulating showing POEM to be comparable to traditional surgery in terms of clinical success and radiologic and manometric post-therapy outcomes. This review discusses the diagnosis and management of achalasia with particular emphasis on the recent developments of HRM and POEM, which arguably represent the most important advances in the field since the advent of laparoscopic Heller myotomy in the 1990s. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Graphic and haptic simulation for transvaginal cholecystectomy training in NOTES.

Science.gov (United States)

Pan, Jun J; Ahn, Woojin; Dargar, Saurabh; Halic, Tansel; Li, Bai C; Sankaranarayanan, Ganesh; Roberts, Kurt; Schwaitzberg, Steven; De, Suvranu

2016-04-01

Natural Orifice Transluminal Endoscopic Surgery (NOTES) provides an emerging surgical technique which usually needs a long learning curve for surgeons. Virtual reality (VR) medical simulators with vision and haptic feedback can usually offer an efficient and cost-effective alternative without risk to the traditional training approaches. Under this motivation, we developed the first virtual reality simulator for transvaginal cholecystectomy in NOTES (VTEST™). This VR-based surgical simulator aims to simulate the hybrid NOTES of cholecystectomy. We use a 6DOF haptic device and a tracking sensor to construct the core hardware component of simulator. For software, an innovative approach based on the inner-spheres is presented to deform the organs in real time. To handle the frequent collision between soft tissue and surgical instruments, an adaptive collision detection method based on GPU is designed and implemented. To give a realistic visual performance of gallbladder fat tissue removal by cautery hook, a multi-layer hexahedral model is presented to simulate the electric dissection of fat tissue. From the experimental results, trainees can operate in real time with high degree of stability and fidelity. A preliminary study was also performed to evaluate the realism and the usefulness of this hybrid NOTES simulator. This prototyped simulation system has been verified by surgeons through a pilot study. Some items of its visual performance and the utility were rated fairly high by the participants during testing. It exhibits the potential to improve the surgical skills of trainee and effectively shorten their learning curve. Copyright © 2016 Elsevier Inc. All rights reserved.

Total Vaginal NOTES Hysterectomy: A New Approach to Hysterectomy.

Science.gov (United States)

Baekelandt, Jan

2015-01-01

The aim of this study was to demonstrate the feasibility of a total hysterectomy performed entirely by transvaginal natural orifice transluminal endoscopic surgery (vNOTES). Conventional, reusable laparoscopic instruments were used, inserted through an inexpensive, self-constructed single-port device. Ten total vaginal NOTES hysterectomies (TVNHs) were performed by a single surgeon. The self-constructed single-port device was made by assembling a surgical glove, a wound protector or modified laryngeal mask airway, 1 reusable 10-mm trocar, and 4 reusable 5-mm trocars. This gloveport was inserted into the vagina to create a pneumovagina. The conventional steps of a vaginal hysterectomy were followed, but performed endoscopically with standard reusable endoscopic instruments. The patient and perioperative data were analyzed. No conversion to standard laparoscopy or laparotomy was necessary in any of the 10 patients who underwent a TVNH. Mean operation time was 97 min (range: 60-120); mean drop in hemoglobin level was 1.5 g/dL (range: 0.5-2.4). There were no operative complications, and postoperative pain scores were very low. This first report on a small number of patients demonstrates that TVNH is possible. By incorporating the advantages of endoscopic surgery, TVNH broadens the indications for vaginal hysterectomy and helps overcome its limitations. At the same time, the NOTES approach avoids abdominal wall wounds and trocar-related complications. TVNH is feasible, even when performed with reusable, conventional laparoscopic instruments. This frugally innovative technique also enables surgeons to perform hysterectomies by vNOTES in low resource settings. Copyright © 2015 AAGL. Published by Elsevier Inc. All rights reserved.

Transgastric pure-NOTES peritoneoscopy and endoscopic ultrasonography for staging of gastrointestinal cancers: a survival and feasibility study.

Science.gov (United States)

Donatsky, Anders Meller; Vilmann, Peter; Meisner, Søren; Jørgensen, Lars Nannestad; Rosenberg, Jacob

2012-06-01

Human natural orifice transluminal endoscopic surgery (NOTES) has mainly been based on simultaneous laparoscopic assistance (hybrid NOTES), forgoing the theoretical benefits of the NOTES technique. This is due to a lack of NOTES-specific instruments and endoscopes, making pure-NOTES procedures difficult and time consuming. An area where pure NOTES could be adopted at its present stage of development is minimally invasive staging of gastrointestinal (GI) cancer. The aim of this study is to evaluate the feasibility of combining transgastric (TG) pure-NOTES peritoneoscopy and intraperitoneal endoscopic ultrasonography (ip-EUS) with intraluminal EUS (il-EUS) for peritoneal evaluation. This was a feasibility and survival study where il-EUS followed by ip-EUS and peritoneoscopy was performed in 10 pigs subjected to TG pure NOTES. A score was given with regard to achieved visualisation of predefined anatomical structures. Survival was assessed at postoperative day (POD) 14. All animals survived until POD 14. Median total procedural time was 94 min (range 74-130 min). Median time for il-EUS, ip-EUS and peritoneoscopy was 11 min (range 7-14 min), 13 min (range 8-20 min) and 10 min (range 6-23 min). Il-EUS, ip-EUS and peritoneoscopy resulted in a score of 15/15 points (range 14-15 points), 6/9 points (range 1-8 points) and 12/13 points (range 8-13 points). TG pure-NOTES peritoneoscopy and ip-EUS combined with il-EUS is feasible and provides sufficient peritoneal evaluation. The technique could have potential for minimally invasive staging of GI cancers.

Do basic psychomotor skills transfer between different image-based procedures?

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Buzink, Sonja N; Goossens, Richard H M; Schoon, Erik J; de Ridder, Huib; Jakimowicz, Jack J

2010-05-01

Surgical techniques that draw from multiple types of image-based procedures (IBP) are increasing, such as Natural Orifice Transluminal Endoscopic Surgery, fusing laparoscopy and flexible endoscopy. However, little is known about the relation between psychomotor skills for performing different types of IBP. For example, do basic psychomotor colonoscopy and laparoscopy skills interact? Following a cross-over study design, 29 naïve endoscopists were trained on the Simbionix GI Mentor and the SimSurgery SEP simulators. Group C (n = 15) commenced with a laparoscopy session, followed by four colonoscopy sessions and a second laparoscopy session. Group L (n = 14) started with a colonoscopy session, followed by four laparoscopy sessions and a second colonoscopy session. No significant differences were found between the performances of group L and group C in their first training sessions on either technique. With additional colonoscopy training, group C outperformed group L in the second laparoscopy training session on the camera navigation task. Overall, training in the basic colonoscopy tasks does not affect performance of basic laparoscopy tasks (and vice versa). However, to limited extent, training of basic psychomotor skills for colonoscopy do appear to contribute to the performance of angled laparoscope navigation tasks. Thus, training and assessment of IBP type-specific skills should focus on each type of tasks independently. Future research should further investigate the influence of psychometric abilities on the performance of IBP and the transfer of skills for physicians who are experienced in one IBP type and would like to become proficient in another type of IBP.

Non-invasive imaging of myocardial bridge by coronary computed tomography angiography: the value of transluminal attenuation gradient to predict significant dynamic compression

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Li, Yuehua; Yu, Mengmeng; Zhang, Jiayin; Li, Minghua [Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, Institute of Diagnostic and Interventional Radiology, Shanghai (China); Lu, Zhigang; Wei, Meng [Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, Department of Cardiology, Shanghai (China)

2017-05-15

To study the diagnostic value of transluminal attenuation gradient (TAG) measured by coronary computed tomography angiography (CCTA) for identifying relevant dynamic compression of myocardial bridge (MB). Patients with confirmed MB who underwent both CCTA and ICA within one month were retrospectively included. TAG was defined as the linear regression coefficient between luminal attenuation and distance. The TAG of MB vessel, length and depth of MB were measured and correlated with the presence and degree of dynamic compression observed at ICA. Systolic compression ≥50 % was considered significant. 302 patients with confirmed MB lesions were included. TAG was lowest (-17.4 ± 6.7 HU/10 mm) in patients with significant dynamic compression and highest in patients without MB compression (-9.5 ± 4.3 HU/10 mm, p < 0.001). Linear correlation revealed relation between the percentage of systolic compression and TAG (Pearson correlation, r = -0.52, p < 0.001) and no significant relation between the percentage of systolic compression and MB depth or length. ROC curve analysis determined the best cut-off value of TAG as -14.8HU/10 mm (area under curve = 0.813, 95 % confidence interval = 0.764-0.855, p < 0.001), which yielded high diagnostic accuracy (82.1 %, 248/302). The degree of ICA-assessed systolic compression of MB significantly correlates with TAG but not MB depth or length. (orig.)

EMR of laterally spreading lesions around or involving the appendiceal orifice: technique, risk factors for failure, and outcomes of a tertiary referral cohort (with video).

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Tate, David J; Desomer, Lobke; Awadie, Halim; Goodrick, Kathleen; Hourigan, Luke; Singh, Rajvinder; Williams, Stephen J; Bourke, Michael J

2018-05-01

EMR of sessile periappendiceal laterally spreading lesions (PA-LSLs) is technically demanding because of poor endoscopic access to the appendiceal lumen and the thin colonic wall at the base of the cecum. We aimed to assess the feasibility and safety of EMR for PA-LSLs. Consecutive LSLs ≥20 mm and PA-LSLs ≥10 mm detected at 3 academic endoscopy centers from September 2008 until January 2017 were eligible. Prospective patient, procedural, and lesion data were collected. PA-LSLs were compared with LSLs in other colonic locations. Thirty-eight PA-LSLs were compared with 1721 LSLs. Referral for surgery without an attempt at EMR was more likely with PA-LSLs (28.9% vs 5.1%, P < .001), and those that involved a greater percentage of the appendiceal orifice (AO) were less likely to be attempted (P = .038). Most PA-LSLs (10/11) were not attempted because of deep extension into the appendiceal lumen; 2 of 11 of these surgical specimens contained invasive cancer. Once attempted, complete clearance of visible adenoma (92.6% PA-LSLs vs 97.6% LSLs, P = .14), adverse events, and rates of adenoma recurrence did not vary significantly between PA-LSLs and LSLs. All 7 patients with prior appendicectomy achieved complete adenoma clearance. There were no cases of post-EMR appendicitis. Twenty of 22 PA-LSLs (91%) eligible for surveillance avoided surgery to longest follow-up. EMR is a safe, effective, and durable treatment for PA-LSLs when specific criteria are fulfilled. If the distal margin of the PA-LSL within the AO cannot be visualized or if more than 50% of the circumference of the orifice is involved, surgery should be considered. (Clinical trial registration number: NTC01368289.). Copyright © 2018. Published by Elsevier Inc.

An Assessment on Temperature Profile of Jet-A/Biodiesel Mixture in a Simple Combustion Chamber with Plain Orifice Atomiser

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Ng, W. X.; Mazlan, N. M.; Ismail, M. A.; Rajendran, P.

2018-05-01

The preliminary study to evaluate influence of biodiesel/kerosene mixtures on combustion temperature profile is explored. A simple cylindrical combustion chamber configuration with plain orifice atomiser is used for the evaluation. The evaluation is performed under stoichiometric air to fuel ratio. Six samples of fuels are used: 100BD (pure biodiesel), 100KE (pure Jet-A), 20KE80BD (20% Jet-A/80% Biodiesel), 40KE60BD (40% Jet-A/60% Biodiesel), 60KE40BD (60% Jet-A/40% Biodiesel), and 80KE20BD (80% Jet-A/20% Biodiesel). Results showed that the oxygen content, viscosity, and lower heating value are key parameters in affecting the temperature profile inside the chamber. Biodiesel is known to have higher energy content, higher viscosity and lower heating value compared to kerosene. Mixing biodiesel with kerosene improves viscosity and caloric value but reduces oxygen content of the fuel. High oxygen content of the biodiesel resulted to the highest flame temperature. However the flame temperature reduce as the percentage of biodiesel in the fuel mixture reduces.

77 FR 11120 - Scientific Information Request on Treatment Strategies for Patients With Peripheral Artery...

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2012-02-24

... transluminal angioplasty, atherectomy, or stents), and/or surgical revascularization (endarterectomy, bypass... endovascular intervention (percutaneous transluminal angioplasty, atherectomy, or stents) and surgical...

Increased Plasma Cathepsin S at the Time of Percutaneous Transluminal Angioplasty is Associated with 6-Months’ Restenosis of the Femoropopliteal Artery

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Mijovski Mojca Bozic

2018-01-01

Full Text Available Background: We tested the hypothesis that increased levels of cathepsin S and decreased levels of cystatin C in plasma at the time of percutaneous transluminal angioplasty (PTA are associated with the occurrence of 6-months’ restenosis of the femoropopliteal artery (FPA. Methods: 20 patients with restenosis and 24 matched patients with patent FPA after a 6-months follow-up were in - cluded in this study. They all exhibited disabling claudication or critical limb ischemia and had undergone technically successful PTA. They were all receiving statins and ACE in hi - bitors (or angiotensin II receptor antagonist before the PTA and the therapy did not change throughout the observational period. Plasma concentrations of C-reactive protein were < 10 mg/L and of creatinine within the reference range at the time of the PTA. Plasma concentration and activity of cathepsin S, together with its potent inhibitor cystatin C, were measured the day before and the day after the PTA. Results: The increased plasma concentration and activity of cathepsin S at the time of PTA was associated with the occurrence of 6-months’ restenosis of FPA, independently of established risk factors (lesion complexity, infrapopliteal run-off vessels, type of PTA, age, gender, smoking, diabetes, lipids and of cystatin C. Plasma cystatin C concentration was not associated with restenosis and did not correlate with cathepsin S activity and concentration in the plasma. Conclusion: Increased level of plasma cathepsin S at the time of PTA is associated with 6-months’ restenosis of PTA, independently of established risk factors.

Gonioscopy assisted transluminal trabeculotomy: an ab interno circumferential trabeculotomy for the treatment of primary congenital glaucoma and juvenile open angle glaucoma.

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Grover, Davinder S; Smith, Oluwatosin; Fellman, Ronald L; Godfrey, David G; Butler, Michelle R; Montes de Oca, Ildamaris; Feuer, William J

2015-08-01

To introduce a novel ab interno 360° trabeculotomy for treating primary congenital glaucoma (PCG) and juvenile open angle glaucoma (JOAG) and report preliminary results. A retrospective chart review of patients who underwent a gonioscopy assisted transluminal trabeculotomy (GATT) procedure by four of the authors (DSG, OS, RLF and DGG) between October 2011 and October 2013. The surgery was performed in patients ≤30 years old with a dysgenic anterior segment angle and uncontrolled PCG and JOAG. Fourteen eyes of 10 patients underwent GATT with follow-up >12 months (12-33 months; mean 20.4). Patients ranged in age from 17 months to 30 years (mean=18.4 years), and five (50%) were female patients. No complications occurred during or following surgery except for early postoperative hyphema in five (36%) of eyes, all cleared by 1 month. The mean intraocular pressure (IOP) decreased from 27.3 to 14.8 mm Hg and the mean number of medications required decreased from 2.6 to 0.86. Five eyes had a drop in IOP ≥15 mm Hg (range 15-39). The preliminary results and safety for GATT, a minimally invasive conjunctival sparing circumferential trabeculotomy, are promising and at least equivalent to previous results for ab externo trabeculotomy for the treatment of PCG and JOAG. All eyes in the study were considered a clinical success. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Post-marketing surveillance in the published medical and grey literature for percutaneous transluminal coronary angioplasty catheters: a systematic review.

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Polisena, Julie; Forster, Alan J; Cimon, Karen; Rabb, Danielle

2013-10-10

Post-marketing surveillance (PMS) may identify rare serious incidents or adverse events due to the long-term use of a medical device, which was not captured in the pre-market process. Percutaneous transluminal coronary angioplasty (PTCA) is a non-surgical procedure that uses a balloon-tipped catheter to enlarge a narrowed artery. In 2011, 1,942 adverse event reports related to the use of PTCA catheters were submitted to the FDA by the manufacturers, an increase from the 883 reported in 2008. The primary research objective is to conduct a systematic review of the published and grey literature published between 2007 and 2012 for the frequency of incidents, adverse events and malfunctions associated with the use of PTCA catheters in patients with coronary artery disease (CAD). Grey literature has not been commercially published. We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials and PubMed for medical literature on PMS for PTCA catheters in patients with CAD published between January 2007 and July 2012. We also searched the grey literature. This review included 11 studies. The in-hospital adverse events reported were individual cases of myocardial infarction and hematoma. In studies of patients with coronary perforation, more patients with balloon angioplasty were identified compared with patients who required stenting. Our systematic review illustrates that the volume and quality of PMS studies associated with the use of PTCA catheters in patients with CAD are low in the published and grey literature, and may not be useful sources of information for decisions on safety. In most studies, the objectives were not to monitor the long-term safety of the use of PTCA catheters in clinical practice. Future studies can explore the strengths and limitations of PMS databases administered by regulatory authorities.

Mathematical modeling of cryogenic spills onto quiescent sea waters followed by pool fires of liquefied natural gas (LNG)

International Nuclear Information System (INIS)

Esteves, Alan Silva; Reis Parise, José Alberto

2013-01-01

Spill and combustion of a pool as a result of a spreading of liquefied natural gas (LNG) at sea from punctures on carrier hulls is presented. Models from literature combined mechanisms of flow thorough an orifice, formation of a semicircular pool, vaporization of a cryogenic fluid by boiling and pool fire heating, ignition, non-premixed turbulent fire with variation with height of the emissive power of the ‘visible’ plume, burning of fuel along the ‘luminous’ zone (fire base) and radiation emitted by gray gases and soot particles from the combustion zone. A review of the experimental data on vaporization velocity and burning rate is presented. Predictions agreed well with existing experimental data and other models. The model simulated fires from 1 to 5 m diameter holes in vessel geometries of 125,000 and 265,000 m 3 . Predictions are plausible, and robust enough to be applied in industrial practice. The construction of an LNG terminal involves, among other parameters, the prediction of thermal radiation fields emitted by pool fires. This is to evaluate safe distances to vulnerable resources around the facility. -- Highlights: • More than 20 orifice models published since 1969 were reviewed. • Flow parameter adjusted with proxy equations for a ∗,max and t * v within 1/3 ≤ ϕ ≤ 30. • Review of experimental of data for vaporization velocities covered since 1978. • The axial emissive power along the fire plume increases with vaporization velocity. • Plume height/diameter ratio of termal plume was nearly insensitive to the scale up of carrier cargo capacity

A method for simulating the release of natural gas from the rupture of high-pressure pipelines in any terrain.

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Deng, Yajun; Hu, Hongbing; Yu, Bo; Sun, Dongliang; Hou, Lei; Liang, Yongtu

2018-01-15

The rupture of a high-pressure natural gas pipeline can pose a serious threat to human life and environment. In this research, a method has been proposed to simulate the release of natural gas from the rupture of high-pressure pipelines in any terrain. The process of gas releases from the rupture of a high-pressure pipeline is divided into three stages, namely the discharge, jet, and dispersion stages. Firstly, a discharge model is established to calculate the release rate of the orifice. Secondly, an improved jet model is proposed to obtain the parameters of the pseudo source. Thirdly, a fast-modeling method applicable to any terrain is introduced. Finally, based upon these three steps, a dispersion model, which can take any terrain into account, is established. Then, the dispersion scenarios of released gas in four different terrains are studied. Moreover, the effects of pipeline pressure, pipeline diameter, wind speed and concentration of hydrogen sulfide on the dispersion scenario in real terrain are systematically analyzed. The results provide significant guidance for risk assessment and contingency planning of a ruptured natural gas pipeline. Copyright © 2017. Published by Elsevier B.V.

Training in peroral endoscopic myotomy (POEM) for esophageal achalasia

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Eleftheriadis, Nicholas; Inoue, Haruhiro; Ikeda, Haruo; Onimaru, Manabu; Yoshida, Akira; Hosoya, Toshihisa; Maselli, Roberta; Kudo, Shin-ei

2012-01-01

Peroral endoscopic myotomy (POEM) has been developed in the context of natural orifice transluminal endoscopic surgery (NOTES) as a minimally invasive endoscopic treatment for symptomatic esophageal achalasia, which is a chronic progressive benign disease with severe morbidity and difficult management. Since September 2008, POEM has been successfully performed in more than 200 consecutive patients with symptomatic achalasia at the Digestive Disease Center of Showa University, Northern Yokohama Hospital, Yokohama, Japan, with excellent short- and long-term results and absence of serious complications. International experience of POEM within clinical studies is also promising. According to these results, POEM is considered as a safe procedure that can be applied to all achalasia patients. However, the low incidence of achalasia (0.3%–1% per 100,000 population), in combination with the potential serious complications related to the technically demanding POEM procedure, has made training difficult. There is therefore an urgent need for an animal model for training to decrease the learning curve. Further, there are other ethical and training issues to address. The pig is the most appropriate animal model for training in POEM due to its anatomy being similar to that of humans. The porcine esophagus has the advantage of easy mobilization due to absence of tight junctions to surrounding organs. A non-survival porcine model would be a simple, inexpensive, and reproducible animal model for training in POEM, without the need for concern about complications. A possible training process might first involve observation of POEM performed by specialists, then training on non-survival and survival porcine models, followed by training in humans under specialist guidance and finally, performance of POEM in humans. PMID:22888256

Influence of the tilt angle of Percutaneous Aortic Prosthesis on Velocity and Shear Stress Fields

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Bruno Alvares de Azevedo Gomes

Full Text Available Abstract Background: Due to the nature of the percutaneous prosthesis deployment process, a variation in its final position is expected. Prosthetic valve placement will define the spatial location of its effective orifice in relation to the aortic annulus. The blood flow pattern in the ascending aorta is related to the aortic remodeling process, and depends on the spatial location of the effective orifice. The hemodynamic effect of small variations in the angle of inclination of the effective orifice has not been studied in detail. Objective: To implement an in vitro simulation to characterize the hydrodynamic blood flow pattern associated with small variations in the effective orifice inclination. Methods: A three-dimensional aortic phantom was constructed, reproducing the anatomy of one patient submitted to percutaneous aortic valve implantation. Flow analysis was performed by use of the Particle Image Velocimetry technique. The flow pattern in the ascending aorta was characterized for six flow rate levels. In addition, six angles of inclination of the effective orifice were assessed. Results: The effective orifice at the -4° and -2° angles directed the main flow towards the anterior wall of the aortic model, inducing asymmetric and high shear stress in that region. However, the effective orifice at the +3° and +5° angles mimics the physiological pattern, centralizing the main flow and promoting a symmetric distribution of shear stress. Conclusion: The measurements performed suggest that small changes in the angle of inclination of the percutaneous prosthesis aid in the generation of a physiological hemodynamic pattern, and can contribute to reduce aortic remodeling.

Transjejunal Extraction of Gallbladder After Mini-Laparoscopic Cholecystectomy in Patients with Previous Roux-en-Y Gastric Bypass: A Small Case Series.

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Kayaalp, Cuneyt; Tardu, Ali; Yagci, Mehmet Ali; Sumer, Fatih

2015-07-01

The length of incisions on the abdominal wall directly correlates with wound-related morbidities and patient comfort. Both mini-laparoscopy (only ≤5-mm trocars) and natural orifice specimen extraction avoid larger abdominal incisions. This study described a new natural orifice translumenal endoscopic surgery (NOTES(®); American Society for Gastrointestinal Endoscopy [Oak Brook, IL] and Society of American Gastrointestinal and Endoscopic Surgeons [Los Angeles, CA]) cholecystectomy technique by combination of these two advanced laparoscopic techniques for cholelithiasis in patients who had prior laparoscopic Roux-en-Y gastric bypass (LRYGB) for obesity. Three patients (two males, one female; 39, 62, and 34 years old, respectively) were admitted with symptomatic cholelithiasis (multiple millimeter-sized gallstones), and all had previously had LRYGB. They were treated by mini-laparoscopic cholecystectomy using three 5-mm trocars. The gallbladder was removed through the dilated efferent limb of the jejunum, 5 cm distal from the gastrojejunostomy. Transjejunal extraction was performed under endoscopic guidance. The gallbladder in the jejenum was passed through the anastomosis and extracted with an endoscopic snare by the transoral way. The enterotomy was closed intracorporeally. There was no conversion or additional trocar requirement. All the procedures were completed successfully without problems. Respective operating times were 95, 75, and 120 minutes. Only 1 patient required postoperative analgesic; the others did not. The patients started to get a liquid diet on the night of surgery and were discharged on Days 1, 1, and 2, respectively, with normal diet recommendations. There were no morbidities. Mini-laparoscopic cholecystectomy is technically feasible in patients with previous LRYGB. Prior LRYGB was not an obstacle for transoral specimen extraction. The dilated efferent jejunal limb is a good alternative route for natural orifice specimen extraction. This

Angioplasty: MedlinePlus Health Topic

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... segment (Medical Encyclopedia) Also in Spanish Directional coronary atherectomy (DCA) (Medical Encyclopedia) Also in Spanish Percutaneous transluminal ... segment Coronary artery balloon angioplasty - slideshow Directional coronary atherectomy ... transluminal coronary angioplasty (PTCA) Stent Related ...

Evaluation of the restenosis of coronary artery after percutaneous transluminal coronary angioplasty by three-dimensional coronary magnetic resonance angiography

International Nuclear Information System (INIS)

Arisaka, Hiraku

2000-01-01

Coronary magnetic resonance angiography (MRA) has been recently brought into clinical use, however, there has not been reports on the comparison with MRA and conventional contrast coronary angiography (CAG) in the detection of the localization and characteristics of coronary restenosis after percutaneous transluminal coronary angioplasty (PTCA). To assess the restenosis of coronary artery after PTCA, this study compared three-dimensional (3D) coronary MRA and CAG. One hundred three patients (76 males and 27 females, average age of 64.6±9.3 years old) were performed coronary MRA at 3-6 months after PTCA. The right coronary artery (RCA) group consist of 21 patients, the left anterior descending branch (LAD) 63 patients and the left circumflex branch (LCX) 19 patients. Coronary MRA was performed with the patients in supine position on a 1.5 T whole body scanner (MAGNETOM VISION, Siemens AG, Germany) using body array coil. The imaging technique used a 3-D gradient echo sequence with respiratory gating and fat suppression. The slice thickness was 2 mm, slab thickness 32 mm, a field of view of 300 mm and a matrix of 128 x 256. Other parameters were an echo time of 2.7 ms and a repetition time of 600 to 1100 msec. The measurement time of 1 imaging slab took 15 to 20 minutes depending on the patient's heart rate. The coronary arteries were reconstructed from the 3-D data set using a multiplanar reconstruction (MPR) technique. According to previous coronary MRA studies, a significant stenosis with a luminal reduction of ≥50% was assumed if a marked signal reduction or signal loss of a vessel segment was visible. In CAG, 57 of 103 patients showed restenosis. In coronary MRA, 37 of 103 patients demonstrated restenosis. The sensitivity, specificity, positive and negative predictive values were 64.9%, 100%, 100% and 69.6%, respectively. Predictive accuracy was 79.6%. Three-dimensional coronary MRA is useful in a noninvasive diagnostic method to evaluate the coronary

Pulmonary edema predictive scoring index (PEPSI), a new index to predict risk of reperfusion pulmonary edema and improvement of hemodynamics in percutaneous transluminal pulmonary angioplasty.

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Inami, Takumi; Kataoka, Masaharu; Shimura, Nobuhiko; Ishiguro, Haruhisa; Yanagisawa, Ryoji; Taguchi, Hiroki; Fukuda, Keiichi; Yoshino, Hideaki; Satoh, Toru

2013-07-01

This study sought to identify useful predictors for hemodynamic improvement and risk of reperfusion pulmonary edema (RPE), a major complication of this procedure. Percutaneous transluminal pulmonary angioplasty (PTPA) has been reported to be effective for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH). PTPA has not been widespread because RPE has not been well predicted. We included 140 consecutive procedures in 54 patients with CTEPH. The flow appearance of the target vessels was graded into 4 groups (Pulmonary Flow Grade), and we proposed PEPSI (Pulmonary Edema Predictive Scoring Index) = (sum total change of Pulmonary Flow Grade scores) × (baseline pulmonary vascular resistance). Correlations between occurrence of RPE and 11 variables, including hemodynamic parameters, number of target vessels, and PEPSI, were analyzed. Hemodynamic parameters significantly improved after median observation period of 6.4 months, and the sum total changes in Pulmonary Flow Grade scores were significantly correlated with the improvement in hemodynamics. Multivariate analysis revealed that PEPSI was the strongest factor correlated with the occurrence of RPE (p PEPSI to be a useful marker of the risk of RPE (cutoff value 35.4, negative predictive value 92.3%). Pulmonary Flow Grade score is useful in determining therapeutic efficacy, and PEPSI is highly supportive to reduce the risk of RPE after PTPA. Using these 2 indexes, PTPA could become a safe and common therapeutic strategy for CTEPH. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Decolorization of Acid Orange 7 by an electric field-assisted modified orifice plate hydrodynamic cavitation system: Optimization of operational parameters.

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Jung, Kyung-Won; Park, Dae-Seon; Hwang, Min-Jin; Ahn, Kyu-Hong

2015-09-01

In this study, the decolorization of Acid Orange 7 (AO-7) with intensified performance was obtained using hydrodynamic cavitation (HC) combined with an electric field (graphite electrodes). As a preliminary step, various HC systems were compared in terms of decolorization, and, among them, the electric field-assisted modified orifice plate HC (EFM-HC) system exhibited perfect decolorization performance within 40 min of reaction time. Interestingly, when H2O2 was injected into the EFM-HC system as an additional oxidant, the reactor performance gradually decreased as the dosing ratio increased; thus, the remaining experiments were performed without H2O2. Subsequently, an optimization process was conducted using response surface methodology with a Box-Behnken design. The inlet pressure, initial pH, applied voltage, and reaction time were chosen as operational key factors, while decolorization was selected as the response variable. The overall performance revealed that the selected parameters were either slightly interdependent, or had significant interactive effects on the decolorization. In the verification test, complete decolorization was observed under statistically optimized conditions. This study suggests that EFM-HC is a useful method for pretreatment of dye wastewater with positive economic and commercial benefits. Copyright © 2015 Elsevier B.V. All rights reserved.

Submucosal tunnel endoscopy: Peroral endoscopic myotomy and peroral endoscopic tumor resection

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Eleftheriadis, Nikolas; Inoue, Haruhiro; Ikeda, Haruo; Onimaru, Manabu; Maselli, Roberta; Santi, Grace

2016-01-01

Peroral endoscopic myotomy (POEM) is an innovative, minimally invasive, endoscopic treatment for esophageal achalasia and other esophageal motility disorders, emerged from the natural orifice transluminal endoscopic surgery procedures, and since the first human case performed by Inoue in 2008, showed exciting results in international level, with more than 4000 cases globally up to now. POEM showed superior characteristics than the standard 100-year-old surgical or laparoscopic Heller myotomy (LHM), not only for all types of esophageal achalasia [classical (I), vigorous (II), spastic (III), Chicago Classification], but also for advanced sigmoid type achalasia (S1 and S2), failed LHM, or other esophageal motility disorders (diffuse esophageal spasm, nutcracker esophagus or Jackhammer esophagus). POEM starts with a mucosal incision, followed by submucosal tunnel creation crossing the esophagogastric junction (EGJ) and myotomy. Finally the mucosal entry is closed with endoscopic clip placement. POEM permitted relatively free choice of myotomy length and localization. Although it is technically demanding procedure, POEM can be performed safely and achieves very good control of dysphagia and chest pain. Gastroesophageal reflux is the most common troublesome side effect, and is well controllable with proton pump inhibitors. Furthermore, POEM opened the era of submucosal tunnel endoscopy, with many other applications. Based on the same principles with POEM, in combination with new technological developments, such as endoscopic suturing, peroral endoscopic tumor resection (POET), is safely and effectively applied for challenging submucosal esophageal, EGJ and gastric cardia tumors (submucosal tumors), emerged from muscularis propria. POET showed up to know promising results, however, it is restricted to specialized centers. The present article reviews the recent data of POEM and POET and discussed controversial issues that need further study and future perspectives. PMID

The transvaginal hybrid NOTES versus conventionally assisted laparoscopic sigmoid resection for diverticular disease (TRANSVERSAL) trial: study protocol for a randomized controlled trial.

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Senft, Jonas D; Warschkow, Rene; Diener, Markus K; Tarantino, Ignazio; Steinemann, Daniel C; Lamm, Sebastian; Simon, Thomas; Zerz, Andreas; Müller-Stich, Beat P; Linke, Georg R

2014-11-20

Natural orifice transluminal endoscopic surgery (NOTES) is the consequence of further development of minimally invasive surgery to reduce abdominal incisions and surgical trauma. The potential benefits are expected to be less postoperative pain, faster convalescence, and reduced risk for incisional hernias and wound infections compared to conventional methods. Recent clinical studies have demonstrated the feasibility and safety of transvaginal NOTES, and transvaginal access is currently the most frequent clinically applied route for NOTES procedures. However, despite increasing clinical application, no firm clinical evidence is available for objective assessment of the potential benefits and risks of transvaginal NOTES compared to the current surgical standard. The TRANSVERSAL trial is designed as a randomized controlled trial to compare transvaginal hybrid NOTES and laparoscopic-assisted sigmoid resection. Female patients referred to elective sigmoid resection due to complicated or reoccurring diverticulitis of the sigmoid colon are considered eligible. The primary endpoint will be pain intensity during mobilization 24 hours postoperatively as measured by the blinded patient and blinded assessor on a visual analogue scale (VAS). Secondary outcomes include daily pain intensity and analgesic use, patient mobility, intraoperative complications, morbidity, length of stay, quality of life, and sexual function. Follow-up visits are scheduled 3, 12, and 36 months after surgery. A total sample size of 58 patients was determined for the analysis of the primary endpoint. The confirmatory analysis will be performed based on the intention-to-treat (ITT) principle. The TRANSVERSAL trial is the first study to compare transvaginal hybrid NOTES and conventionally assisted laparoscopic surgery for colonic resection in a randomized controlled setting. The results of the TRANSVERSAL trial will allow objective assessment of the potential benefits and risks of NOTES compared to the

Comparison of immediate postoperative pain after transvaginal versus traditional laparoscopic cholecystectomy.

Science.gov (United States)

Wood, Stephanie G; Dabu-Bondoc, Susan; Dai, Feng; Mikhael, Hosni; Vadivelu, Nalini; Roberts, Kurt E

2014-04-01

Transvaginal cholecystectomy (TVC) is the most common natural orifice transluminal surgery (NOTES) performed in women, yet there is a paucity of data on intraoperative and immediate postoperative pain management. Previous studies have demonstrated that NOTES procedures are associated with less postoperative pain and faster recovery times. This study analyzes intraoperative and postoperative opioid use for TVC compared with traditional four-port laparoscopic cholecystectomies (LCs). This is a retrospective analysis of consecutive TVC and LC female patients between August 2009 and August 2012 in an academic institution. We compared demographics, intraoperative and postoperative opioid use and times in the operating room (OR) and in the post anesthesia care unit (PACU). A total of 68 TVC and 67 LC patients were included in this study. The TVC and LC groups were similar in terms of age (both 41 years) and body mass index (29 and 31 kg/m2, respectively). The intraoperative preparation, surgical, and emergence times were significantly longer for the TVC than for the LC (p ≤ 0.01). Compared with the LC group, the intraoperative opioid requirement was significantly greater (TVC 27 mg vs. LC 25 mg; p = 0.003), but after adjusting for anesthesia time, the difference in OR opioid consumption became non-significant (p = 0.08). The PACU opioid requirement (TVC 2.5 vs. LC 5 mg; p = 0.04) was significantly lower for the TVC group, and a greater proportion of patients did not need any pain medications (TVC 38 % vs. LC 21 %; p = 0.04), compared with the LC group. The average PACU pain scores were not significantly different between the groups (p = 0.45). TVC patients did not experience more pain than LC patients. Although the average pain scores of TVC patients did not differ from those of the LC patients, TVC patients did require less pain medication in the PACU.

Cirurgia por orifícios naturais transcolônica: acesso NOTES peri-retal (PNA para excisão mesoretal total Transcolonic natural orifice surgery: peri-rectal NOTES access (PNA for total mesorectal excision

Directory of Open Access Journals (Sweden)

Ricardo Zorron

2010-03-01

Full Text Available OBJETIVOS: Cirurgia por orifícios naturais tem sido recentemente aplicada em series clínicas para cirurgia abdominal. Apesar de potenciais vantagens do acesso NOTES transcolônico para doenças colorretais, este ainda não havia sido utilizado clinicamente. O presente trabalho descreve a primeira aplicação bem-sucedida de NOTES transcolônico da literatura, em uma nova abordagem de excisão mesoretal total (TME para cancer de reto. MÉTODOS: Foi obtida aprovação de Comitê de Ética em Pesquisa para cirurgias por orifícios naturais, e o paciente assinou termo de consentimento informado. Em um paciente de 54 anos portador de adenocarcinoma de reto, o procedimento de retossigmoidectomia e linfadenectomia, com excisão mesoretal total foi realizada utilizando um acesso posterior transcolônico pouco acima da borda anal. A dissecção mesorretal foi conseguida utilizando um colonoscópio flexível e instrumentos endoscópicos, com assistência laparoscópica. O espécime foi retirado via transanal, e anastomose foi transorificial, com estoma proximal de proteção. RESULTADOS: O tempo operatório foi de 350 min, não ocorrendo complicações operatórias. A evolução pós-operatória foi favorável, e o paciente recebeu alta no sexto dia de pós-operatório com dieta plena. CONCLUSÃO: Este primeiro relato bem sucedido de cirurgia NOTES transcolônica traz potencialmente novas fronteiras de aplicações clínicas na cirurgia minimamente invasiva. O tratamento de doenças colorretais utilizando o novo acesso flexível PNA (Perirectal NOTES Access é uma promissora nova abordagem, paralelamente à laparoscopia e cirurgia aberta, para melhoria do tratamento dos pacientes.OBJECTIVES: Clinical natural orifice surgery has been applied for abdominal surgery in recent years. Despite potential advantages of transcolonic NOTES for colorectal diseases, it was since now not yet clinically applied. The study describes the first successful human

Development and in vitro evaluation of diclofenac sodium loaded mucoadhesive microsphere with natural gum for sustained delivery.

Science.gov (United States)

Amin, Md Lutful; Jesmeen, Tasbira; Sutradhar, Kumar Bishwajit; Mannan, Md Abdul

2013-12-01

The objective of this study was to develop and evaluate mucoadhesive microsphere of diclofenac sodium with natural gums for sustained delivery. Guar gum and tragacanth were used along with sodium alginate as mucoadhesive polymers. Microspheres were formulated using orifice-ionic gelation method. Particle size, surface morphology, swelling study and drug entrapment efficiency of the prepared microspheres were determined. In vitro evaluation was carried out comprising of mucoadhesion and drug release study. The prepared microspheres were discrete and free flowing. Sodium alginate and natural gum, at a ratio of 1:0.25, showed good mucoadhesive property and they had high drug entrapment efficiencies. They also exhibited the best rate retarding effect among all the formulations. Drug entrapment efficiency of all the microspheres ranged from 80.42% to 91.67%. An inverse relationship was found between extent of crosslinking and drug release rate. Release rate was slow and extended in case of the formulations of 1:0.25 ratio (F1 and F3), releasing 68.36% and 70.56% drug respectively after 8 hours. Tragacanth-containing microspheres of F1 showed superiority over other formulations, with best mucoadhesive and rate retarding profile. The correlation value (r(2)) indicated that the drug release of all the formulations followed Higuchi's model. Overall, the results indicated that mucoadhesive microspheres containing natural gum can be promising in terms of prolonged delivery with good mucoadhesive action, targeting the absorption site to thrive oral drug delivery.

Interventional treatment of renal artery stenosis: a mid-term evaluation of clinical efficacy

International Nuclear Information System (INIS)

Liu Jing; Zhang Xitong

2009-01-01

Objective: To assess the clinical efficacy of interventional management for the treatment of renal artery stenosis. Methods: Percutaneous transluminal balloon renal angioplasty and / or percutaneous transluminal renal artery stenting were performed in 47 patients with renal artery stenosis (55 stenosed arteries in total). A follow-up study on the blood pressure and renal function was conducted and the results were statistically analyzed. Results: Fifty-four stenosed renal arteries were successfully reopened, of which only percutaneous transluminal balloon angioplasty was adopted in 17 and percutaneous transluminal renal artery stenting in 37. One patient died during the procedure. A follow-up for a mean period of (2.5 ± 0.6) years was carried out. The blood pressure determined at one (n = 46), 6 (n = 46), 12 (n = 33) and 24 (n = 29) months after the treatment was significantly decreased when compared to that determined before the treatment (P < 0.01). The clinical effective rate was 89.13% (41 / 46), 72.73% (24 / 33) and 62.07% (18 / 29), respectively. After the therapy,the renal function was improved in 5, remained unchanged in 33 and became worse in 3 patients. The comparison of the post-operative renograms (obtained within 2 months) with the pre-operative ones showed that in eight patients there was an increase in renal blood flow with an improvement in renal function impairment, which took a turn from severe degree to mild or moderate degree. Nevertheless, severe impairment in renal blood flow remained in 3 patients. Conclusion: Percutaneous transluminal balloon renal angioplasty and percutaneous transluminal renal artery stenting are safe and effective treatments for the renal artery stenosis, which also has a beneficial effect on the related renal hypertension and renal insufficiency. (authors)

Effect of distributor on performance of a continuous fluidized bed dryer

Science.gov (United States)

Yogendrasasidhar, D.; Srinivas, G.; Pydi Setty, Y.

2018-03-01

Proper gas distribution is very important in fluidized bed drying in industrial practice. Improper distribution of gas may lead to non-idealities like channeling, short circuiting and accumulation which gives rise to non-uniform quality of dried product. Gas distribution depends on the distributor plate used. Gas distribution mainly depends on orifice diameter, number of orifices and opening area of the distributor plate. Small orifice diameter leads to clogging, and a large orifice diameter gives uneven distribution of gas. The present work involves experimental studies using different distributor plates and simulation studies using ASPEN PLUS steady state simulator. The effect of various parameters such as orifice diameter, number of orifices and the opening area of the distributor plate on the performance of fluidized bed dryer have been studied through simulation and experimentation. Simulations were carried out (i) with increasing air inlet temperature to study the characteristics of solid temperature and moisture in outlet (ii) with increasing orifice diameter and (iii) with increase in number orifices to study the solid outlet temperature profiles. It can be observed from the simulation that, an increase in orifice diameter and number orifices increases solid outlet temperature upto certain condition and then after there is no effect with further increase. Experiments were carried out with increasing opening area (3.4 to 42%) in the form of increasing orifice diameter keeping the number of orifices constant and increasing number of orifices of the distributor plate keeping the orifice diameter constant. It can be seen that the drying rate and solid outlet temperature increase upto certain condition and then after with further increase in the orifice diameter and number of orifices, the change in the drying rate and solid outlet temperature observed is little. The optimum values of orifice diameter and number of orifices from experimentation are found to be 5

Survival and sudden cardiac death after septal ablation for hypertrophic obstructive cardiomyopathy

DEFF Research Database (Denmark)

Jensen, Morten Kvistholm; Havndrup, Ole; Hassager, Christian

2011-01-01

Reports of long-term survival and the risk of sudden cardiac death (SCD) after percutaneous transluminal septal myocardial ablation (PTSMA) in patients with hypertrophic obstructive cardiomyopathy (HOCM) are sparse.......Reports of long-term survival and the risk of sudden cardiac death (SCD) after percutaneous transluminal septal myocardial ablation (PTSMA) in patients with hypertrophic obstructive cardiomyopathy (HOCM) are sparse....

The Relationship Between Neutrophil–Lymphocyte Ratio and Primary Patency of Percutaneous Transluminal Angioplasty in Hemodialysis Arteriovenous Fistula Stenosis When Using Conventional and Drug-Eluting Balloons

Energy Technology Data Exchange (ETDEWEB)

Çildağ, Mehmet Burak, E-mail: mbcildag@yahoo.com [Adnan Menderes University, Department of Diagnostic and Interventional Radiology (Turkey); Çildağ, Songül, E-mail: songulcildag@yahoo.com [Adnan Menderes University, Department of Immunology and Allergy (Turkey); Köseoğlu, Ömer Faruk Kutsi, E-mail: kutsikoseoglu@yahoo.com [Adnan Menderes University, Department of Diagnostic and Interventional Radiology (Turkey)

2016-12-15

ObjectiveThe aim of this study is to investigate the potential association of neutrophil–lymphocyte ratio (NLR) between primary patency of percutaneous transluminal angioplasty (PTA) in hemodialysis arteriovenous fistula stenosis and type (Conventional and Drug-Eluting) of balloons used in PTA.Material-MethodThis retrospective study consists of 78 patients with significant arteriovenous fistulas stenosis who were treated with PTA by using Drug-Eluting Balloon (DEB) (n = 29) or Conventional Balloon (CB) (n = 49). NLR was calculated from preinterventional blood samples. All patients were classified into two groups. Group A; primary patency <12 months (43/78), Group B; primary patency ≥12 months (35/78). Cox regression analysis and Kaplan–Meier method were used to determine respectively independent factors affecting the primary patency and to compare the primary patency for the two balloon types.ResultsNLR ratio and balloon type of the two groups were significantly different (p = 0.002, p = 0.010). The cut-off value of NLR was 3.18 for determination of primary patency, with sensitivity of 81.4 % and specificity of 51.4 %. Primary patency rates between PTA with DEB and CB displayed statistically significant differences (p < 0.05). The cut-off value was 3.28 for determination of 12-month primary patency with the conventional balloon group; sensitivity was 81.8 % and specificity was 81.3 %. There was no statistical relation between NLR levels and the drug-eluting balloon group in 12-month primary patency (p = 0.927).ConclusionIncreased level of NLR may be a risk factor in the development of early AVF restenosis after successful PTA. Preferring Drug-Eluting Balloon at an increased level of NLR can be beneficial to prolong patency.

Apparatus for use in radioimmunoassays

International Nuclear Information System (INIS)

Chen, C-H.; Tsay, H-M.; Heyer, R.E.

1979-01-01

Apparatus for solid-phase antibody separation techniques used in radioimmunoassays is described in this invention. It consists of a rectangular prism tray with multiple wells protruding into its interior from one side. Near the base of the tray is an orifice used for creating evacuated condition within the structure. At the base of each well there is an orifice of such size and shape as to retain an aqueous liquid under given pressure conditions but permit the evacuation of this liquid at reduced pressure. The outlet of these orifices is in the shape of an inverted conical frustrum. Each of the wells contains an antibody coated disc of porous cellulose paper surrounded by a plastic support. The porous nature of the cellulose paper ensures contact between the antibody coating and the antigen. The use of antibody coated porous cellulose paper in combination with the vacuum operated apparatus simplifies the manipulative steps whilst still maintaining the sensitivity of the radioimmunoassay. It also obviates the need for aspiration and thus lessens the risk of contamination from one sample to another. (UK)

Balloon angioplasty in acute and chronic coronary artery disease

International Nuclear Information System (INIS)

Holmes, D.R. Jr.; Vlietstra, R.E.

1989-01-01

Percutaneous transluminal coronary angioplasty has grown exponentially since its introduction. Currently, selection criteria include single-vessel and multivessel disease, stable and unstable angina, and acute infarction. The outcome depends on specific patient and antiographic characteristics. In ideal lesions, success rates should be greater than 90%, with low morbidity and mortality. With more severe and diffuse multivessel disease, success rates are lower and complication rates are higher. In these cases, percutaneous transluminal coronary angioplasty still offers a reasonable option, provided complete revascularization can be achieved or the angina-producing lesion dilated. Numerous issues remain unresolved, including (1) the role of percutaneous transluminal coronary angioplasty vs coronary surgery (currently being tested), (2) restenosis, which occurs in approximately 30% of treated lesions, and (3) organizational adjustments such as training and certification to maintain high standards of care

Natural convection in closed vertical cylinders with particular reference to gas cooled reactor standpipes

International Nuclear Information System (INIS)

Spence, I.D.

1975-09-01

The access to the core for fuel assemblies and control rods of the Advanced Gas Cooled Reactor is through the top cap by means of standpipes. The standpipe is essentially a cylindrical, vertical tube with cooled side wall, closed upper end and an orifice at the lower end which is exposed to the hot core fluid. This creates confined natural convection flow in the empty standpipe and this is the subject of this thesis. The investigation is carried out using analytical and experimental methods. For the analytical work, solution of laminar and turbulent flow is attempted using finite-difference computer techniques. The laminar flow performance is evaluated using two different finite-difference procedures, and the results are compared to each other and to existing analytical and experimental results for the open thermosyphon with cool inflow and hot sidewall, i.e. the complementary problem to the present one. For turbulent flow a two equation turbulence model is employed which provides transport equations for the kinetic energy of turbulence and its dissipation rate. The experimental rig is a full scale replica of the Advanced Gas Cooled Reactor control rod mechanism standpipe. Carbon dioxide and helium are used as the working fluids for the series of tests. (author)

Transluminal coronary angioplasty in the treatment of silent ischemia

International Nuclear Information System (INIS)

Bergin, P.; Myler, R.K.; Shaw, R.E.; Stertzer, S.H.; Clark, D.A.; Ryan, C.; Murphy, M.C.

1988-01-01

Fifty-four asymptomatic patients with positive thallium exercise tests underwent coronary angiography followed by coronary angioplasty (PTCA), as the primary therapy for silent ischemia. The procedure was technically successful in 89% of these patients. Emergency bypass graft surgery was necessary in 2 (3.6%) and q-wave myocardial infarction occurred in 1 (1.8%) of these. All fifty-four patients have been followed for a mean of 35 months since angioplasty. Of the 48 patients with initially successful PTCA, 12 had either clinical restenosis (9/14 or 19%) or a new lesion (3/48 or 6%) during follow-up, which required a repeat PTCA. At the longest follow-up, 46 (85%) had been successfully treated with on or more PTCA procedures. Two patients (3.6%) had sustained late q-wave myocardial infarction and two additional patients reported angina pectoris. There were no deaths. Angioplasty as a primary therapy for silent ischemia appears efficacious, with success and restenosis rates comparable to those in the symptomatic population. Event-free survival is improved, compared with natural history data for patients with silent ischemia from other studies. Prudent risk/benefit analysis may help to define subgroups most likely to benefit from this intervention

Left ventricular mass regression is independent of gradient drop and effective orifice area after aortic valve replacement with a porcine bioprosthesis.

Science.gov (United States)

Sádaba, Justo Rafael; Herregods, Marie-Christine; Bogaert, Jan; Harringer, Wolfgang; Gerosa, Gino

2012-11-01

The question of whether left ventricular mass (LVM) regression following aortic valve replacement (AVR) is affected by the prosthesis indexed effective orifice area (IEOA) and transprosthetic gradient has not been fully elucidated. Data from a prospective, core-laboratory-reviewed echocardiography and magnetic resonance imaging (MRI) study was used to determine if the degree of LVM regression following AVR with two types of porcine bioprosthesis in patients suffering from predominant aortic valve stenosis (AS) was related to the prosthesis IEOA and transprosthetic gradient. Over a two-year period, 149 patients enrolled at eight centers received either an Epic or an Epic Supra aortic bioprosthesis (St. Jude Medical, MN, USA). Preoperative valve dysfunction was pure AS in 54 patients (36%) and mixed valve disease (primarily stenosis) in 95 patients (64%). LVM was determined preoperatively and at six months postoperatively, using MRI. The prosthesis IEOA and transprosthetic gradient were calculated at six months by means of echocardiography. Data were available for 111 patients at both enrolment and six months postoperatively. The LVM at enrolment and at follow up was 154.96 +/- 42.50 g and 114.83 +/- 29.20 g, respectively (p regression methods, showed LVM regression to be independent of the mean systolic pressure gradient, peak systolic pressure and prosthesis IEOA at six months (p = 0.53, 0.43, and 0.15, respectively). At six months after AVR with a porcine bioprosthesis to treat AS, there was a significant LVM regression that was independent of the prosthesis IEOA and the mean systolic pressure gradient and peak systolic pressure.

Training in peroral endoscopic myotomy (POEM for esophageal achalasia

Directory of Open Access Journals (Sweden)

Eleftheriadis N

2012-07-01

Full Text Available Nicholas Eleftheriadis, Haruhiro Inoue, Haruo Ikeda, Manabu Onimaru, Akira Yoshida, Toshihisa Hosoya, Roberta Maselli, Shin-ei KudoDigestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, JapanAbstract: Peroral endoscopic myotomy (POEM has been developed in the context of natural orifice transluminal endoscopic surgery (NOTES as a minimally invasive endoscopic treatment for symptomatic esophageal achalasia, which is a chronic progressive benign disease with severe morbidity and difficult management. Since September 2008, POEM has been successfully performed in more than 200 consecutive patients with symptomatic achalasia at the Digestive Disease Center of Showa University, Northern Yokohama Hospital, Yokohama, Japan, with excellent short- and long-term results and absence of serious complications. International experience of POEM within clinical studies is also promising. According to these results, POEM is considered as a safe procedure that can be applied to all achalasia patients. However, the low incidence of achalasia (0.3%–1% per 100,000 population, in combination with the potential serious complications related to the technically demanding POEM procedure, has made training difficult. There is therefore an urgent need for an animal model for training to decrease the learning curve. Further, there are other ethical and training issues to address. The pig is the most appropriate animal model for training in POEM due to its anatomy being similar to that of humans. The porcine esophagus has the advantage of easy mobilization due to absence of tight junctions to surrounding organs. A non-survival porcine model would be a simple, inexpensive, and reproducible animal model for training in POEM, without the need for concern about complications. A possible training process might first involve observation of POEM performed by specialists, then training on non-survival and survival porcine models, followed by training in

Hybrid NOTES transvaginal cholecystectomy: operative and long-term results after 18 cases.

Science.gov (United States)

Pugliese, Raffaele; Forgione, Antonello; Sansonna, Fabio; Ferrari, Giovanni Carlo; Di Lernia, Stefano; Magistro, Carmelo

2010-03-01

Natural orifice transluminal endoscopic surgery (NOTES) is a novel technique that aims at reducing or abolishing skin incisions and potentially also postoperative pain. The purpose of this study was to analyse operative and long-term results of a series of hybrid transvaginal cholecystectomy. Between July 2007 and May 2009, transvaginal NOTES cholecystectomy for symptomatic cholelithiasis was performed by a hybrid technique in 18 women (mean age 54 years), including four women with a body mass index >30 kg/m(2). Dissection was conducted in the first four cases by a round-tip unipolar electrode (UE) introduced through the operative channel of the endoscope coming from the vagina and in the last 14 cases by a ultrasonic scalpel (US) introduced through a 5-mm abdominal port. The short-term outcomes and the long-term results of the two methods were compared. The transvaginal approach entailed no intraoperative complication and no conversion. The overall mean duration of procedures was 75 min (range 40-190). In the first four cases (UE), the operating time was 148 min (range 140-190), whilst in the last 14 (US), it was considerably shorter, 53 min (range 40-60, p < 0.01). We experienced one biliary leak in the UE group, whilst morbidity with US was nil (p < 0.005). The biliary leak healed in 7 days with nasobiliary drainage. No other complications were encountered in either group. The mean follow-up was 12 months (range 1-22), and none of the patients has complained of dyspareunia or other colpotomy-related complications so far. Until specifically designed endoscopic tools are available for NOTES, the hybrid technique with US dissection conducted through a 5-mm port should be preferred in transvaginal cholecystectomy in order to shorten the duration of surgery and make this approach effective, safe and reproducible. After a mean follow-up of 1 year, none of our patients has complained of any problem related to transvaginal approach.

True NOTES TME resection with splenic flexure release, high ligation of IMA, and side-to-end hand-sewn coloanal anastomosis.

Science.gov (United States)

Marks, John H; Lopez-Acevedo, Nicolas; Krishnan, Barath; Johnson, Matthew N; Montenegro, Grace A; Marks, Gerald J

2016-10-01

Natural orifice transluminal endoscopic surgery (NOTES) represents the ultimate expression of minimally invasive surgery. We have developed and present here an initial feasibility and safety study of transanal total mesorectal excision (TME) with splenic flexure release, high ligation of the IMA and IMV, and side-to-end coloanal anastomosis with temporary diverting ileostomy for rectal cancer. A program of full NOTES TME resection with release of the splenic flexure, high ligation of the IMA/IMV, with side-to-end coloanal anastomosis was performed transanally from December 2013 to July 2014. Demographics, preoperative, perioperative, and postoperative data were prospectively obtained. Operative components were broken into TME, colonic mobilization, splenic flexure release, IMA/IMV transection, transanal extraction of specimen, and coloanal anastomosis for analysis of performance completion. There were 3 women and 1 man on whom we operated. Mean age was 56 (46-65). Mean BMI was 26 (23.8-30.2). The operation was completed entirely transanally in 2 patients. Transanal component completion of the operation was as follows: TME in 3/4; colonic mobilization in 4/4; splenic flexure release in 3/4; IMA/IMV transection in 3/4; transanal specimen extraction in 4/4; coloanal anastomosis in 4/4. Abdominal time for completion of component parts was: splenic flexure release 4:53 (min:s), IMA/IMV 19:43, completion of TME 13:41. Mean EBL was 194 cc (25-500). Aside from stoma site, there were no abdominal incisions. There were no mortalities. Mesorectum was intact in all 4 patients and with negative circumferential and distal margins. This experience supports the feasibility and safety of a true NOTES TME. The critical anatomic views demonstrated on video affirm the potential of this approach for distal rectal cancer. Colorectal surgery represents the most logical application for NOTES. While highly promising, a great deal of work remains to develop the technique and applicability

[Transoral thyroid and parathyroid surgery : Implementation and evaluation of the transoral endoscopic technique via the vestibular approach (TOETVA)].

Science.gov (United States)

Karakas, E; Anuwong, A; Ketwong, K; Kounnamas, A; Schopf, S; Klein, G

2018-04-10

More than 10 years ago various research groups in Germany first reported the possibility of transoral surgery of the thyroid and parathyroid glands. These were developed and evaluated within the framework of natural orifice transluminal endoscopic surgery (NOTES). While development of these innovative and new techniques that enabled surgery without visible scars did not become well accepted in Europe and America, it led to an optimized transoral endoscopic thyroidectomy vestibular approach (TOETVA), which was implemented particularly in Asia. We report the preparation, step-by-step implementation, and first promising results for TOETVA of an international surgical cooperation. A Thai-Austrian-German cooperation was started in June 2017. Between June and November 2017 the first 10 TOETVA procedures were performed in female and male patient(s) presenting with single thyroid nodules, sporadic primary hyperparathyroidism and solitary parathyroid adenoma or thyroglossal duct cysts. The TOETVA technique was performed using 3 laparoscopic ports inserted at the oral vestibule and a CO 2 insufflation pressure at 6-8 mm Hg. Each surgery was performed using laparoscopic instruments and ultrasonic or bipolar devices. Surgical outcome, complications and conversions to an open technique were recorded. Of the patients six presented with single thyroid nodules, two patients had multinodular goitre with scintigraphically cold nodules and multifocal hyperfunctioning thyroid tissue, one patient suffered from sporadic primary hyperparathyroidism with a left sided parathyroid adenoma and one patient suffered from a thyroglossal duct cyst. No conversion to conventional open surgery was necessary. Average tumor size was 3.1 cm (range 1-4 cm). There was no relevant loss of blood or subsequent bleeding. No temporary or permanent hoarseness or mental nerve injury occurred, while transient hypoparathyroidism was evident after successful parathyroid resection. Of the patients five

Experimental and numerical investigations of BWR fuel bundle inlet flow

International Nuclear Information System (INIS)

Hoashi, E; Morooka, S; Ishitori, T; Komita, H; Endo, T; Honda, H; Yamamoto, T; Kato, T; Kawamura, S

2009-01-01

We have been studying the mechanism of the flow pattern near the fuel bundle inlet of BWR using both flow visualization test and computational fluid dynamics (CFD) simulation. In the visualization test, both single- and multi-bundle test sections were used. The former test section includes only a corner orifice facing two support beams and the latter simulates 16 bundles surrounded by four beams. An observation window is set on the side of the walls imitating the support beams upstream of the orifices in both test sections. In the CFD simulation, as well as the visualization test, the single-bundle model is composed of one bundle with a corner orifice and the multi-bundle model is a 1/4 cut of the test section that includes 4 bundles with the following four orifices: a corner orifice facing the corner of the two neighboring support beams, a center orifice at the opposite side from the corner orifice, and two side orifices. Twin-vortices were observed just upstream of the corner orifice in the multi-bundle test as well as the single-bundle test. A single-vortex and a vortex filament were observed at the side orifice inlet and no vortex was observed at the center orifice. These flow patterns were also predicted in the CFD simulation using Reynolds Stress Model as a turbulent model and the results were in good agreement with the test results mentioned above. (author)

FLOW-INDUCED VIBRATION IN PIPES: CHALLENGESS AND SOLUTIONS - A REVIEW

Directory of Open Access Journals (Sweden)

M. SIBA

2016-03-01

Full Text Available The Flow-induced vibration has recently been the topic of experimental, numerical, and theoretical studies. It was intended to implement better applications for controlling the flow using orifice technique. Having the flow under control, the orifice becomes an instrument for measuring the flow. The flow of all fluid such as water, oil, gas and vapours through an orifice was tested and mathematical models were developed adequately. The basic theme for these enormous studies was the need for the very accurate flow measurements through orifices. All experimental, theoretical, numerical, and analytical studies have agreed that there is more than one avenue to develop, modify, and enhance such measurements. However, one factor that affects the flow measurements is the vibration which was not treated as required until the mid-20th century due to enormous discoveries that damages could be rooted to vibration. Researchers have studied vibration and then proposed mathematical models in conjunction with the pressure and velocity measurements of the flowing fluids and then the effect of the vibration, induced or not induced, has been under continuous investigation. This paper is an attempt to review the previous studies regarding understanding the nature of the vibration and the possible effects of vibration on the flow and on the piping structure in order to limit the damage caused by the vibration. This study shows that the need for more experimental studies and more comprehensive analytical approaches are, in particular, very essential to develop better results.

[Value of evaluating the coronary collateral circulation by transluminal attenuation gradient in patients with chronic total occlusion and related influencing factors].

Science.gov (United States)

Chen, Y L; Wang, R; He, Y; Li, J N; Yuan, F; Tian, R; Ge, C J; Zhou, Y; Huang, R C; Cui, S; Song, X T

2017-10-24

Objective: To observe the value of evaluating the coronary collateral circulation of chronic total occlusion (CTO) by transluminal attenuation gradient (TAG) and Rentrop grading, and analyze the influencing factors for coronary collateral circulation. Methods: A total of 179 CTO patients admitted to Beijing Anzhen hospital during June 2013 to August 2016 were included in this study.All patients received coronary computed tomographic angiography (CCTA) examination before coronary angiography.Finally, 75 patients (79 vessels) were enrolled.Patients were divided into two groups on the basis of Rentrop classification.The Rentrop 3 was defined as a well-developed coronary collateral circulation group, including 50 CTO vessels, Rentrop 2 or below was defined as poorly-developed collateral circulation group, including 29 vessels.TAG values in patients with various Rentrop grades were analyzed.Univariate and multivariate analysis were used to determine the predictors of collateral circulation. Results: TAG increased consistently in proportion to the angiographic extent of collateral flow (TAG was (-33.6±24.4), (-16.5±15.7) and (-12.8±15.8) HU/10 mm in patients with Rentrop grade 0 or 1, 2 and 3, respectively, P =0.007). Number of good collateral circulation vessels predicted by TAG≥15.6 HU/10 mm was 45(57.0%, 45/79), and 50 (63.3%, 50/79) by Rentrop grade ( P =0.383). Prevalence of diabetes was significantly lower (20.8%(10/48) vs. 48.1%(13/27), P =0.01), while history of previous myocardial infarction (MI) was significantly higher (35.4%(17/48) vs. 11.1%(3/27), P =0.02) in patients with good collateral circulation than in patients with poor collateral circulation.The TAG of the good collateral circulation group was significantly higher than in poorly collateral circulation group ((-12.8±15.8) HU/10 mm vs. (-21.2±19.6) HU/10mm, P =0.041). Multiple logistic regression analysis revealed that history of MI ( OR =0.196, 95% CI 0.041-0.936, P =0.041) and diabetes( OR =6

A scaling study of the natural circulation flow of the ex-vessel core catcher cooling system of a 1400MW PWR for designing a scale-down test facility

International Nuclear Information System (INIS)

Rhee, Bo. W.; Ha, K. S.; Park, R. J.; Song, J. H.

2012-01-01

A scaling study on the steady state natural circulation flow along the flow path of the ex-vessel core catcher cooling system of 1400MWe PWR is described. The scaling criteria for reproducing the same thermalhydraulic characteristics of the natural circulation flow as the prototype core catcher cooling system in the scale-down test facility is derived and the resulting natural circulation flow characteristics of the prototype and scale-down facility analyzed and compared. The purpose of this study is to apply the similarity law to the prototype EU-APR1400 core catcher cooling system and the model test facility of this prototype system and derive a relationship between the heating channel characteristics and the down-comer piping characteristics so as to determine the down-comer pipe size and the orifice size of the model test facility. As the geometry and the heating wall heat flux of the heating channel of the model test facility will be the same as those of the prototype core catcher cooling system except the width of the heating channel is reduced, the axial distribution of the coolant quality (or void fraction) is expected to resemble each other between the prototype and model facility. Thus using this fact, the down-comer piping design characteristics of the model facility can be determined from the relationship derived from the similarity law

Revascularização miocárdica de urgência após complicação de angioplastia transluminal coronária: abordagem cirúrgica atual Emergency myocardial revascularization after complicated percutaneous transluminal coronary angioplasty: actual surgical approach

Directory of Open Access Journals (Sweden)

Luís Alberto Dallan

1990-04-01

transluminal coronary angioplasty (PTCA. Seventy-nine (3.2% patients subsequently underwent emergency miocardial revascularization, and 32 (40.5% developed myocardial infarction with 12 (15.2% deaths. The operative mortality rate was significantly increased among elderly patients, those with left main occlusive dissection, late coronary thrombosis, and specially among patients with hemodynamic instability after PTCA. Additional minutes or hours of low myocardial and systemic perfusion after failed PTCA also increase the risk of immediate surgical revascularization. Despite the growing role of PTCA in the treatment of more complex coronary atherosclerotic heart diseases, the number of failed procedures that necessitate coronary artery bypass surgery decreased last two years (10/1351. This have been possible by placing a reperfusion catheter (Stack across the narrowed coronary artery lumen. Surgical results were consistently improved by modifications in myocardial protection techniques, besides the use of reperfusion catheter after failed PTCA.

Analytical evaluation on dynamical response characteristics of reduced-moderation water reactor with tight-lattice core under natural circulation core cooling

International Nuclear Information System (INIS)

Ishikawa, Nobuyuki; Okubo, Tsutomu

2009-01-01

The time-domain analyses with TRAC-BF1 code were performed for clarifying the dynamical response characteristics of the reduced-moderation water reactor (RMWR) with tight-lattice core configuration. The response characteristics were evaluated based on the step response basically utilized for dynamical system evaluation. As for the most fundamental dynamical characteristics, the channel flow response characteristics of single fuel assembly were evaluated. In the evaluation, the appropriate single-phase pressure drop setting at the inlet orifice was determined in terms of response stability from the design viewpoint. In addition, from the investigation on the relation of the response and transit time of coolant, it is confirmed that the channel flow response of RMWR is dominated by the transit time of vapor phase resulting from a high void fraction operation condition. As for a natural circulation flow response, it is clarified that the response is strongly influenced by the effect of two-phase pressure loss owing to a high void fraction condition. The reactor power response with reactivity feedback shows quite stable response characteristics on account of the small absolute value of void reactivity coefficient.

Impact of body image on patients' attitude towards conventional, minimal invasive, and natural orifice surgery.

Science.gov (United States)

Lamadé, Wolfram; Friedrich, Colin; Ulmer, Christoph; Basar, Tarkan; Weiss, Heinz; Thon, Klaus-Peter

2011-03-01

A series of investigations proposed that patients' preference on minimal invasive and scarless surgery may be influenced by age, sex, and surgical as well as endoscopic history of the individual patient. However, it is unknown which psychological criteria lead to the acceptance of increased personal surgical risk or increased personal expenses in patients demanding scarless operations. We investigated whether individual body image contributes to the patient's readiness to assume higher risk in favor of potentially increased cosmesis. We conducted a nonrandomized survey among 63 consecutive surgical patients after receiving surgery. Individual body image perception was assessed postoperatively applying the FKB-20 questionnaire extended by four additional items. The FKB-20 questionnaire is a validated tool for measuring body image disturbances resulting in a two-dimensional score with negative body image (NBI) and vital body dynamics (VBD) being the two resulting scores. A subgroup analysis was performed according to the conducted operations: conventional open surgery = group 1, traditional laparoscopic surgery = group 2, and no scar surgery = group 3. There was a significant correlation between a negative body image and the preference for scar sparing and scarless surgery indicated by a significantly increased acceptance of surgical risks and the willingness to spend additional money for receiving scarless surgery (r = 0.333; p = 0.0227). Allocated to operation subgroups, 17 of 63 patients belonged to group 1 (OS), 29 to group 2 (minimally invasive surgery), and 17 patients to group 3 (no scar). Although age and sex were unequally distributed, the groups were homogenous regarding body mass index and body image (NBI). Subgroup analysis revealed that postoperative desire for scar sparing approaches was most frequently expressed by patients who received no scar operations. Patients with an NBI tend towards scarless surgery and are willing to accept increased operative risk and to spend additional money for improved postoperative cosmesis.

Single-incision laparoscopic surgery through an ostomy site: a natural approach by an unnatural orifice.

Science.gov (United States)

Lopez, Nicole E; Peterson, Carrie Y; Ramamoorthy, Sonia L; McLemore, Elisabeth C; Sedrak, Michael F; Lowy, Andrew M; Horgan, Santiago; Talamini, Mark A; Sicklick, Jason K

2015-02-01

Single-incision laparoscopic surgery (SILS) is gaining popularity for a wide variety of surgical operations and capitalizes on the benefits of traditional laparoscopic surgery without incurring multiple incision sites. Traditionally, SILS is performed by a midline periumbilical approach. However, such a minimally invasive approach may be utilized in patients who already have an abdominal incision. Our series retrospectively reviews 7 cases in which we utilized the fascial defect at the time of after ostomy reversal as our SILS incision site. In turn, we performed a variety of concurrent intra-abdominal procedures with excellent technical success and outcomes. Our study is the largest single-institution case series of this novel approach and suggests that utilizing an existing ostomy-site abdominal incision is a safe and effective location for SILS port placement and should be considered in patients undergoing concurrent procedures.

Pioneers of invasive cardiovascular medicine - Charles Theodore dotter and colleagues: Short historical review

Directory of Open Access Journals (Sweden)

Kostić Jelena

2014-01-01

Full Text Available Within modern medicine at the beginning of 21st century, we are witnessing a revolutionary development of the invasive diagnostics and therapy of cardiovascular system diseases. With the discovery of X-rays at the end of 19th century by Wilhelm Roentgen, it is appropriate to reflect on the gifted individuals whose efforts drastically altered radiology and cardiology. The early techniques used in peripheral percutaneous transluminal angioplasty form the basis for subsequent percutaneous intervention both in the peripheral and coronary arteries and are largely the contribution of Charles Dotter. The main goal of his work was the use of catheters for diagnosis and treatment in an attempt to replace the scalpel. He was 20 years ahead of his time, especially with percutaneous transluminal angioplasty. The first percutaneous transluminal angioplasty marked a new era in the treatment of peripheral atherosclerotic lesions. This practical genius dedicated his considerable energy to the belief that there is always a better way to treat disease. His personal contributions to clinical medicine, research, and teaching have saved millions of limbs and lives all over the world. European physicians, who were more open to unproven techniques, almost immediately embraced percutaneous transluminal angioplasty. Without the contribution and help of his colleagues, Forssmann, Sones and Gruntzig, all of them pioneers, nothing would be done. They were all ahead of there time and opened completely new chapter in medicine.

Kronisk tarmiskæmi hos en yngre patient

DEFF Research Database (Denmark)

Hansen, Lars Koch; Kammerlander, Heidi; Cecere, Stefano

2012-01-01

A 46 year-old woman presented with classic symptoms. Computed tomography-angiography and duplex ultrasonography showed stenosis of the aa. mesenteria superior et inferior. The patient was moved to a university hospital and a percutaneous transluminal angioplasty with insertion of stents was perfo......A 46 year-old woman presented with classic symptoms. Computed tomography-angiography and duplex ultrasonography showed stenosis of the aa. mesenteria superior et inferior. The patient was moved to a university hospital and a percutaneous transluminal angioplasty with insertion of stents...... was performed. She was discharged shortly after feeling well....

Process of motion by unit steps over a surface provided with elements regularly arranged

International Nuclear Information System (INIS)

Cooper, D.E.; Hendee, L.C. III; Hill, W.G. Jr.; Leshem, Adam; Marugg, M.L.

1977-01-01

This invention concerns a process for moving by unit steps an apparatus travelling over a surface provided with an array of orifices aligned and evenly spaced in several lines and several parallel rows regularly spaced, the lines and rows being parallel to axes x and y of Cartesian co-ordinates, each orifice having a separate address in the Cartesian co-ordinate system. The surface travelling apparatus has two previously connected arms aranged in directions transversal to each other thus forming an angle corresponding to the intersection of axes x and y. In the inspection and/or repair of nuclear or similar steam generator tubes, it is desirable that such an apparatus should be able to move in front of a surface comprising an array of orifices by the selective alternate introduction and retraction of two sets of anchoring claws of the two respective arms, in relation to the orifices of the array, it being possible to shift the arms in a movement of translation, transversally to each other, as a set of claws is withdrawn from the orifices. The invention concerns a process and aparatus as indicated above that reduces to a minimum the path length of the apparatus between the orifices it is effectively opposite and a given orifice [fr

A study of response time of pitot pressure probes designed for rapid response and protection of transducer

Science.gov (United States)

Moore, J. A.

1979-01-01

An eight orifice probe, designed to protect the transducer without the use of a baffle, was compared to a standard orifice-baffle probe in the small shock tube and in the expansion tube under normal run conditions. In both facilities, the response time of eight orifice probe was considerable better than the standard probe design.

Colecistectomía transvaginal (NOTES combinada con minilaparoscopia Transvaginal cholecystectomy (NOTES combined with minilaparoscopy

Directory of Open Access Journals (Sweden)

C. Dolz

2007-12-01

Veres needle in the umbilical fundus, followed by the insertion of a 5-mm trocar. A second 3-mm trocar was placed in the right upper quadrant. A colpotomy was performed, and a 12-mm trocar placed inside the vagina allowed the insertion of a videogastroscope as far as the hilum of the liver. Results: cholecystectomy was performed by using a combination of working tools inserted through the entry port for the minilaparoscopy and the videogastroscope. The gallbladder was removed transvaginally through the videogastroscope. There were no postoperative complications, and the patient was discharged within 24 hours. Conclusions: transvaginal cholecystectomy is possible and safe when performed by a multidisciplinary team working together. Natural orifice transluminal endoscopic surgery (NOTES is an emerging modality that seeks to be less invasive, better tolerated, and more respectful of esthetics than laparoscopic surgery. It will probably open the way for very important medical and technological innovations over the coming years.

Medline Plus

Full Text Available ... breast Macular degeneration Nerve conduction Osteoarthritis Osteoporosis Ovulation Parkinson disease Percutaneous transluminal coronary angioplasty (PTCA) Peristalsis Phagocytosis ...

Medline Plus

Full Text Available ... breast Macular degeneration Nerve conduction Osteoarthritis Osteoporosis Ovulation Parkinson disease Percutaneous transluminal coronary angioplasty (PTCA) Peristalsis Phagocytosis Pituitary ...

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

Fuel temperature influence on the performance of a last generation common-rail diesel ballistic injector. Part II: 1D model development, validation and analysis

International Nuclear Information System (INIS)

Payri, R.; Salvador, F.J.; Carreres, M.; De la Morena, J.

2016-01-01

Highlights: • A 1D model of a solenoid common-rail ballistic injector is implemented in AMESim. • A detailed dimensional and a hydraulic characterization lead to a fair validation. • Fuel temperature influence on injector dynamics is assessed through 1D simulations. • Temperature impacts through changes in inlet orifice regime and viscous friction. • Cold fuel temperature leads to a slower injection opening due to high viscosity. - Abstract: A one-dimensional model of a solenoid-driven common-rail diesel injector has been developed in order to study the influence of fuel temperature on the injection process. The model has been implemented after a thorough characterization of the injector, both from the dimensional and the hydraulic point of view. In this sense, experimental tools for the determination of the geometry of the injector lines and orifices have been described in the paper, together with the hydraulic setup introduced to characterize the flow behaviour through the calibrated orifices. An extensive validation of the model has been performed by comparing the modelled mass flow rate against the experimental results introduced in the first part of the paper, which were performed for different engine-like operating conditions involving a wide range of fuel temperatures, injection pressures and energizing times. In that first part of the study, an important influence of the fuel temperature was reported, especially in terms of the dynamic behaviour of the injector, due to its ballistic nature. The results from the model have allowed to explain and further extend the findings of the experimental study by analyzing key features of the injector dynamics, such as the pressure drop established in the control volume due to the control orifices performance or the forces due to viscous friction, also assessing their influence on the needle lift laws.

Influence of three mechanical bileaflet prosthetic valve designs on the three-dimensional flow field inside a simulated aorta.

Science.gov (United States)

Akutsu, Toshinosuke; Matsumoto, Akira

2010-12-01

The current design of the bileaflet valve, the leaflets of which open outside first, differs significantly from the natural valve whose leaflets open center first. This difference generates a completely different flow field in the bileaflet valve compared to that in the natural heart valve. In a previous study, it was demonstrated that the valve design greatly affects the aortic flow field as well as the circulatory flow inside sinuses of Valsalva, using saline solution as a working fluid. A limited discussion on the turbulence flow field that could be generated by the valve was provided. In this continuation of that study, therefore, a dynamic PIV study was conducted to analyze the influence of the heart valve design on the aortic flow field, and particularly on the turbulent profile. This study also aimed to determine the influence of the viscosity of the testing fluid. Three bileaflet prostheses-the St. Jude Medical (SJM), the On-X, and the MIRA valves-were tested under pulsatile flow conditions. Flow through the central orifice of the SJM valve was slower than that through the newer designs. The newer designs tend to show strong flow through all orifices. The On-X valve generates simple jet-type flow while the MIRA valve with circumferentially curved leaflets generates a strong but three-dimensionally diffuse flow, resulting in a more complex flow field downstream of the aortic valve with higher turbulence. A 180° orientation that is more popular clinically seems to provide a less diffuse flow than a 90° orientation. The effect of increasing the viscosity was found to be an increase in the flow velocity through the central orifice and a more organized flow field for all of the valves tested.

Effectiveness of selective intracoronary thrombolysis in acute myocardial infarction

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Hiroshi; Nosaka, Hideyuki; Saitoh, Taroh

1984-10-01

Protective effects of percutaneous transluminal coronary recanalization (PTCR) on the myocardium were investigated by creatine phosphokinase levels, regional left ventricular wall motion in chronic stage and /sup 201/Tl myocardial single photon emission computed tomography. Recanalization of the occlusive coronary artery at the early stage of myocardial infarction was effective for the protection of the myocardium and heart functions. This effect depended largely on the degree of occlusion at the time of the first imaging, the final degree of occlusion after recanalization, and the time required for the recanalization. Cases in which percutaneous transluminal coronary angiography was performed following PTCR are also presented and examined. (Namekawa, K.).

Effectiveness of selective intracoronary thrombolysis in acute myocardial infarction

International Nuclear Information System (INIS)

Yamaguchi, Hiroshi; Nosaka, Hideyuki; Saitoh, Taroh

1984-01-01

Protective effects of percutaneous transluminal coronary recanalization (PTCR) on the myocardium were investigated by creatine phospho kinase levels, regional left ventricular wall motion in chronic stage and 201 Tl myocardial single photon emission computed tomography. Recanalization of the occlusive coronary artery at the early stage of myocardial infarction was effective for the protection of the myocardium and heart functions. This effect depended largely on the degree of occlusion at the time of the first imaging, the final degree of occlusion after recanalization, and the time required for the recanalization. Cases in which percutaneous transluminal coronary angiography was performed following PTCR are also presented and examined. (Namekawa, K.)

Pressure drop in ET-RR-1

International Nuclear Information System (INIS)

Khattab, M.; Mina, A.R.

1990-01-01

Measurements of pressure drop through a bundle comprising 16 rods and their lower arrangement grid as well as orifices similar to those of ET-RR-1 core have been done. Experiments are carried out under adiabatic turbulent flow conditions at about 35 degree C. Bundle Reynolds number range is 4 x 10 -2 x 10. Orifices of diameters 4.5, 3.25 or 2.5 cm. are mounted underneath the bundle. The bundle and lower grid pressure drop coefficients are 3.75 and 1.8 respectively. Orifices pressure drop coefficients are 2.65, 19.67 and 53.55 respectively. The ratio of bundle pressure drop to that of 4.5 cm. Orifice diameter is 1.415. The pressure drop coefficients are utilizer to calculate flow through bundles. The flow rate per bundle is 39.1, 20.4 or 13.1 m 3 /hr. Depending on orifice diameter

External Cylindrical Nozzle with Controlled Vacuum

Directory of Open Access Journals (Sweden)

V. N. Pil'gunov

2015-01-01

Full Text Available There is a developed design of the external cylindrical nozzle with a vacuum camera. The paper studies the nozzle controllability of flow rate via regulated connection of the evacuated chamber to the atmosphere through an air throttle. Working capacity of the nozzle with inlet round or triangular orifice are researched. The gap is provided in the nozzle design between the external wall of the inlet orifice and the end face of the straight case in the nozzle case. The presented mathematical model of the nozzle with the evacuated chamber allows us to estimate the expected vacuum amount in the compressed section of a stream and maximum permissible absolute pressure at the inlet orifice. The paper gives experimental characteristics of the fluid flow process through the nozzle for different values of internal diameter of a straight case and an extent of its end face remoteness from an external wall of the inlet orifice. It estimates how geometry of nozzle constructive elements influences on the volume flow rate. It is established that the nozzle capacity significantly depends on the shape of inlet orifice. Triangular orifice nozzles steadily work in the mode of completely filled flow area of the straight case at much more amounts of the limit pressure of the flow. Vacuum depth in the evacuated chamber also depends on the shape of inlet orifice: the greatest vacuum is reached in a nozzle with the triangular orifice which 1.5 times exceeds the greatest vacuum with the round orifice. Possibility to control nozzle capacity through the regulated connection of the evacuated chamber to the atmosphere was experimentally estimated, thus depth of flow rate regulation of the nozzle with a triangular orifice was 45% in comparison with 10% regulation depth of the nozzle with a round orifice. Depth of regulation calculated by a mathematical model appeared to be much more. The paper presents experimental dependences of the flow coefficients of nozzle input orifice

Surgery with cooperative robots.

Science.gov (United States)

Lehman, Amy C; Berg, Kyle A; Dumpert, Jason; Wood, Nathan A; Visty, Abigail Q; Rentschler, Mark E; Platt, Stephen R; Farritor, Shane M; Oleynikov, Dmitry

2008-03-01

Advances in endoscopic techniques for abdominal procedures continue to reduce the invasiveness of surgery. Gaining access to the peritoneal cavity through small incisions prompted the first significant shift in general surgery. The complete elimination of external incisions through natural orifice access is potentially the next step in reducing patient trauma. While minimally invasive techniques offer significant patient advantages, the procedures are surgically challenging. Robotic surgical systems are being developed that address the visualization and manipulation limitations, but many of these systems remain constrained by the entry incisions. Alternatively, miniature in vivo robots are being developed that are completely inserted into the peritoneal cavity for laparoscopic and natural orifice procedures. These robots can provide vision and task assistance without the constraints of the entry incision, and can reduce the number of incisions required for laparoscopic procedures. In this study, a series of minimally invasive animal-model surgeries were performed using multiple miniature in vivo robots in cooperation with existing laparoscopy and endoscopy tools as well as the da Vinci Surgical System. These procedures demonstrate that miniature in vivo robots can address the visualization constraints of minimally invasive surgery by providing video feedback and task assistance from arbitrary orientations within the peritoneal cavity.

Numerical Simulation of Twin Nozzle Injectors

OpenAIRE

Milak, Dino

2015-01-01

Fuel injectors for marine applications have traditionally utilized nozzles with symmetric equispaced orifice configuration. But in light of the new marine emission legislations the twin nozzle concept has arisen. The twin nozzle differs from the conventional configuration by utilizing two closely spaced orifices to substitute each orifice in the conventional nozzle. Injector manufacturers regard twin nozzle injectors as a promising approach to facilitate stable spray patterns independent of t...

The current state of per oral endoscopic myotomy for achalasia

Science.gov (United States)

Smith, Shane P.

2017-01-01

Achalasia is an acquired neuromuscular disorder that has been treated using a variety of modalities throughout medical history. Recently, the technique of per oral endoscopic myotomy (POEM) was introduced to treat the disease using a truly minimally invasive, natural orifice technique that is rapidly being adopted across the world. This review outlines the development of POEM, the technique itself, and gives a comparison to other procedures, specifically laparoscopic Heller myotomy (LHM). PMID:29078682

Multistage-multiorifice flow fractionation (MS-MOFF): continuous size-based separation of microspheres using multiple series of contraction/expansion microchannels.

Science.gov (United States)

Sim, Tae Seok; Kwon, Kiho; Park, Jae Chan; Lee, Jeong-Gun; Jung, Hyo-Il

2011-01-07

Previously we introduced a novel hydrodynamic method using a multi-orifice microchannel for size-based particle separation, which is called a multi-orifice flow fractionation (MOFF). The MOFF has several advantages such as continuous, non-intrusive, and minimal power consumption. However, it has a limitation that the recovery yield is relatively low. Although the recovery may be increased by adjusting parameters such as the Reynolds number and central collecting region, poor purity inevitably followed. We newly designed and fabricated a microfluidic channel for multi-stage multi-orifice flow fractionation (MS-MOFF), which is made by combining three multi-orifice segments, and consists of 3 inlets, 3 filters, 3 multi-orifice segments and 5 outlets. The structure and dimensions of the MS-MOFF were determined by the hydrodynamic principles to have constant Reynolds numbers at each multi-orifice segment. Polystyrene microspheres of two different sizes (7 μm and 15 μm) were tested. With this device, we made an attempt to improve recovery and minimize loss of purity by collecting and re-separating non-selected particles of the first separation. The final recovery successfully increased from 73.2% to 88.7% while the final purity slightly decreased from 91.4% to 89.1% (for 15 μm). These values were never achievable with the single-stage MOFF (SS-MOFF) having only one multi-orifice segment in our previous work. The MS-MOFF channel will be useful for clinical applications, such as separation of circulating tumor cells (CTC) or rare cells from human blood samples.

Morphologic observation of mucosa-associated lymphoid tissue in the large intestine of Bactrian camels (Camelus bactrianus).

Science.gov (United States)

ZhaXi, Yingpai; Wang, Wenhui; Zhang, Wangdong; Gao, Qiang; Guo, Minggang; Jia, Shuai

2014-07-01

The structure and distribution of the mucosa-associated lymphoid tissue (MALT) throughout the large intestine of 10 Bactrian camels were comparatively studied by anatomical and histological methods. The results showed that Peyer's patches (PPs) were mainly located on the mucosal surfaces of the entire ileocecal orifice, the beginning of the cecum and the first third of the colon. The shape of PPs gradually changed from "scrotiform" to "faviform" along the large intestine with the scrotiform PP as the major type in the ileocecal orifice. The distribution density also gradually decreased from the ileocecal orifice to the colon. The histological observations further revealed that the MALT in the form of PPs or isolated lymphoid follicles (ILF) and lamina propria lymphocytes was mainly present in the lamina propria and submucosa from the entire ileocecal orifice, where the muscularis mucosa is usually incomplete, to the colonic forepart. In addition, lymphoid tissue was much more abundant in the lamina propria and submucosa of the ileocecal orifice as compared to the cecum and colon. Statistically, the MALT of the ileocecal orifice contained a higher number of lymphoid follicles (37.7/10 mm(2) ) than that of the cecum, colon, or rectum (P lymphoid follicles were clearly visible. Together, our data suggest that the ileocecal orifice constitutes the main inductive site for the mucosal immunity in the large intestine of the Bactrian camel; and that scrotiform PPs are likely to the result of long-term adaptation of the Bactrian camel to the harsh living environment. © 2014 Wiley Periodicals, Inc.

Below knee angioplasty in elderly patients: Predictors of major adverse clinical outcomes.

LENUS (Irish Health Repository)

Keeling, Aoife N

2011-03-01

To determine predictors of clinical outcome following percutaneous transluminal angioplasty (PTA) in elderly patients with below knee atherosclerotic lesions causing intermittent claudication (IC) or critical limb ischaemia (CLI).

Mixing and NOx Emission Calculations of Confined Reacting Jet Flows in Cylindrical and Annular Ducts

Science.gov (United States)

Oechsle, Victor L.; Connor, Christopher H.; Holdeman, James D. (Technical Monitor)

2000-01-01

Rapid mixing of cold lateral jets with hot cross-stream flows in confined configurations is of practical interest in gas turbine combustors as it strongly affects combustor exit temperature quality, and gaseous emissions in for example rich-lean combustion. It is therefore important to further improve our fundamental understanding of the important processes of dilution jet mixing especially when the injected jet mass flow rate exceeds that of the cross-stream. The results reported in this report describe some of the main flow characteristics which develop in the mixing process in a cylindrical duct. A three-dimensional computational fluid dynamics (CFD) code has been used to predict the mixing flow field characteristics and NOx emission in a quench section of a rich-burn/quick-mix/lean-burn (RQL) combustor. Sixty configurations have been analyzed in both circular and annular geometries in a fully reacting environment simulating the operating condition of an actual RQL gas turbine combustion liner. The evaluation matrix was constructed by varying the number of orifices per row and orifice shape. Other parameters such as J (momentum-flux ratio), MR (mass flowrate ratio), DR (density ratio), and mixer sector orifice ACd (effective orifice area) were maintained constant throughout the entire study. The results indicate that the mixing flow field can be correlated with the NOx production if they are referenced with the stoichiometric equivalence ratio value and not the equilibrium value. The mixing flowfields in both circular and annular mixers are different. The penetration of equal jets in both annular and circular geometries is vastly different which significantly affects the performance of the mixing section. In the computational results with the circular mixer, most of the NOx formation occurred behind the orifice starting at the orifice wake region. General trends have been observed in the NOx production as the number of orifices is changed and this appears to be

Comparative evaluation of a two stroke compressed natural gas mixer design using simulation and experimental techniques

Energy Technology Data Exchange (ETDEWEB)

Ramasamy, D.; Bakar, R.A.; Rahim, M.F.; Noor, M.M. [Malaysia Pahang Univ., Pahang (Malaysia). Automotive Focus Group

2008-07-01

A study was conducted in which a two-stroke engine was converted for use with bi-fuel, notably compressed natural gas and gasoline. The excessive by-products generated by two-stroke engine combustion can be attributed to the inefficient combustion process. This prototype uniflow-type single-cylinder engine was equipped with a bi-fuel conversion system. A dedicated mixer was also developed to meter the gaseous fuel through the engine intake system. It was designed to meet air and fuel requirement similar to its gasoline counterpart. The mixer was modeled to obtain optimum orifice diameter using three different sizes of 14, 16 and 18 mm respectively. A standard computational fluid dynamics (CFD) software package was used to simulate the flow. A pressure reading was obtained during the prototype test. The drop in pressure across the venturi was shown to be an important parameter as it determined the actual fuel-air ratio in the actual engine. A good agreement of CFD outputs with that of the experimental outputs was recorded. The experimental technique validated the pressure distribution predicted by CFD means on the effects of the three insert rings in the CNG mixer. The simulation exercise can be used to predict the amount of CNG consumed by the engine. It was concluded that the 14 mm throat ring was best suited for the CNG mixer because it provided the best suction. Once the mixer is tested on a real engine, it will clear any doubts as to whether the throat can function at high engine speeds. 5 refs., 3 tabs., 8 figs.

Plasma characteristics in the discharge region of a 20 A emission current hollow cathode

Science.gov (United States)

Mingming, SUN; Tianping, ZHANG; Xiaodong, WEN; Weilong, GUO; Jiayao, SONG

2018-02-01

Numerical calculation and fluid simulation methods were used to obtain the plasma characteristics in the discharge region of the LIPS-300 ion thruster’s 20 A emission current hollow cathode and to verify the structural design of the emitter. The results of the two methods indicated that the highest plasma density and electron temperature, which improved significantly in the orifice region, were located in the discharge region of the hollow cathode. The magnitude of plasma density was about 1021 m-3 in the emitter and orifice regions, as obtained by numerical calculations, but decreased exponentially in the plume region with the distance from the orifice exit. Meanwhile, compared to the emitter region, the electron temperature and current improved by about 36% in the orifice region. The hollow cathode performance test results were in good agreement with the numerical calculation results, which proved that that the structural design of the emitter and the orifice met the requirements of a 20 A emission current. The numerical calculation method can be used to estimate plasma characteristics in the preliminary design stage of hollow cathodes.

Detailed evaluation of two phase natural circulation flow in the cooling channel of the ex-vessel core catcher for EU-APR1400

Energy Technology Data Exchange (ETDEWEB)

Park, Rae-Joon, E-mail: rjpark@kaeri.re.kr; Ha, Kwang-Soon; Rhee, Bo-Wook; Kim, Hwan Yeol

2016-03-15

Highlights: • Ex-vessel core catcher of PECS is installed in EU-APR1400. • CE-PECS has been conducted to test a cooling capability of the PECS. • Two phase flow in CE-PECS and PECS was analyzed using RELAP5/MOD3. • RELAP5 results are very similar to the CE-PECS data. • The super-step design is suitable for steam injection into the downcomer in PECS. - Abstract: The ex-vessel core catcher of the PECS (Passive Ex-vessel corium retaining and Cooling System) is installed to retain and cool down the corium in the reactor cavity of the EU (European Union)-APR (Advanced Power Reactor) 1400. A verification experiment on the cooling capability of the PECS has been conducted in the CE (Cooling Experiment)-PECS. Simulations of a two-phase natural circulation flow using the RELAP5/MOD3 computer code in the CE-PECS and PECS have been conducted to predict the two-phase flow characteristics, to determine the natural circulation mass flow rate in the cooling channel, and to evaluate the scaling in the experimental design of the CE-PECS. Particularly from a comparative study of the prototype PECS and the scaled test facility of the CE-PECS, the orifice loss coefficient in the CE-PECS was found to be 6 to maintain the coolant circulation mass flux, which is approximately 273.1 kg/m{sup 2} s. The RELAP5 results on the coolant circulation mass flow rate are very similar to the CE-PECS experimental results. An increase in the coolant injection temperature and the heat flux lead to an increase in the coolant circulation mass flow rate. In the base case simulation, a lot of vapor was injected into the downcomer, which leads to an instability of the two-phase natural circulation flow. A super-step design at a downcomer inlet is suitable to prevent vapor injection into the downcomer piping.

Detailed evaluation of two phase natural circulation flow in the cooling channel of the ex-vessel core catcher for EU-APR1400

International Nuclear Information System (INIS)

Park, Rae-Joon; Ha, Kwang-Soon; Rhee, Bo-Wook; Kim, Hwan Yeol

2016-01-01

Highlights: • Ex-vessel core catcher of PECS is installed in EU-APR1400. • CE-PECS has been conducted to test a cooling capability of the PECS. • Two phase flow in CE-PECS and PECS was analyzed using RELAP5/MOD3. • RELAP5 results are very similar to the CE-PECS data. • The super-step design is suitable for steam injection into the downcomer in PECS. - Abstract: The ex-vessel core catcher of the PECS (Passive Ex-vessel corium retaining and Cooling System) is installed to retain and cool down the corium in the reactor cavity of the EU (European Union)-APR (Advanced Power Reactor) 1400. A verification experiment on the cooling capability of the PECS has been conducted in the CE (Cooling Experiment)-PECS. Simulations of a two-phase natural circulation flow using the RELAP5/MOD3 computer code in the CE-PECS and PECS have been conducted to predict the two-phase flow characteristics, to determine the natural circulation mass flow rate in the cooling channel, and to evaluate the scaling in the experimental design of the CE-PECS. Particularly from a comparative study of the prototype PECS and the scaled test facility of the CE-PECS, the orifice loss coefficient in the CE-PECS was found to be 6 to maintain the coolant circulation mass flux, which is approximately 273.1 kg/m"2 s. The RELAP5 results on the coolant circulation mass flow rate are very similar to the CE-PECS experimental results. An increase in the coolant injection temperature and the heat flux lead to an increase in the coolant circulation mass flow rate. In the base case simulation, a lot of vapor was injected into the downcomer, which leads to an instability of the two-phase natural circulation flow. A super-step design at a downcomer inlet is suitable to prevent vapor injection into the downcomer piping.

Orifice diseases project - experience of the "Hospital das Clínicas" University of São Paulo Medical Center in day-hospital of anorectal disease Projeto doenças orificiais experiência do HCFMUSP em hospital-dia e doenças anorretais

Directory of Open Access Journals (Sweden)

Sergio Carlos Nahas

1999-06-01

Full Text Available The treatment of malignant or benign colorectal pathologies that require more complex management are priorities in tertiary hospitals such as "Hospital das Clínicas" University of São Paulo Medical Center (HCFMUSP. Therefore, benign, uncomplicated orifice conditions are relegated to second place. The number of patients with hemorrhoids, perianal fistulas, fissures, condylomas and pilonidal cysts who seek treatment at the HFMUSP is very great, resulting in over-crowding in the outpatient clinics and a long waiting list for recommended surgical treatment (at times over 18 months. The authors describe the experience of the HCFMUSP over an eight-day period with day-hospital surgery in which 140 patients underwent surgery. Data was prospectively taken on the patients undergoing surgery for benign orifice pathologies including age, sex, diagnosis, surgery performed, immediate and late postoperative complications, and follow-up. 140 patients operated on over eight days were studied. 68 were males (48.75% with ages ranging from 25 to 62 (mean 35.2 yrs.. Hemorrhoids was the most frequent condition encountered (82 hemorrhoidectomies, 58.6%, followed by perineal fistula (28 fistula repairs, 20.0%. The most common complication was headache secondary to rachianesthesia occurring in 9 patients (6.4%. One patient (0.7% developed bleeding immediately PO that required reoperation. Mean follow-up was 104 days. Day-surgery characterized by quality care and low morbidity is feasible in tertiary public hospitals, permitting surgery for benign orifice pathologies on many patients within a short period of time.O tratamento das patologias colorretais malignas ou benignas, que necessitam tratamento com maior grau de complexidade são prioridades em hospitais terciários, como é o Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP, permanecendo assim as patologias orificiais benignas em um segundo plano. Todavia devido à sua

Disintegration of materials by cavitating microjets

Directory of Open Access Journals (Sweden)

Mlkvik M.

2013-04-01

Full Text Available In the paper is presented an investigation of material disintegration by cavitating microjets. Cavitating microjet develops behind the micro-orifice at high flow speeds, when local pressure drop initiates a cavitation phenomenon. Described is a method and presented are selected results of experiments. Experiments were carried out with 2 micro-orifices at different flow conditions (cavitation number, distance between sample and micro-orifice. Experiments are based on flow visualisation as well as on a character of material displacement.

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

Process and apparatus for sealing nuclear reactor fuel

International Nuclear Information System (INIS)

Duncan, R.; Barna, R.P.

1978-01-01

A process and apparatus for simultaneously pressurizing a fuel rod having a plug in one end, welding a plug in the other end and sealing a gas pressurizing orifice therein in a single operation is described. A weld chamber is provided which accommodates one end of a seal rod having a plug fixed in the rod end by a friction fit. A mechanism pushes the fuel rod into the weld chamber which is then pressurized to force gas through a plug orifice into the fuel rod. During subsequent rotation of the rod, an electrode in the weld chamber forms a weld puddle which bridges the end plug-fuel rod interface and the plug orifice to thereby weld the plug in the rod and seal the plug orifice in a single operation. 6 claims, 3 figures

Cough urethrocystography: The best radiological evaluation of female stress urinary incontinence?

International Nuclear Information System (INIS)

Varpula, M.; Maekinen, J.; Kiilholma, P.

1989-01-01

Urethrocystography and simultaneous urethrocystometry were performed on 40 women with primary urinary incontinence. The posterior urethrovesical angle, inclination angle, urethropelvic angle, and an orifice descent angle, not earlier described, were measured on radiographs obtained at rest, during coughing and during straining. The orifice descent angle was used to describe the descent of the internal urethral orifice in the cough radiographs, and was the only measurement that provided a significant correlation with urethrocystometry. The other angles measured, and radiographs obtained at rest or during straining were not useful in the evaluation of female stress urinary incontinence. The authors conclude that the best imaging method for the evaluation of female stress urinary incontinence is urethrocystography employing a single lateral view taken during coughing, with measurement of the orifice descent angle. (orig.)

Numerical calculation for flow field of servo-tube guided hydraulic control rod driving system

International Nuclear Information System (INIS)

He Keyu; Han Weishi

2010-01-01

A new-style hydraulic control rod driving mechanism was put forward by using servo-tube control elements for the design of control rod driving mechanism. The results of numerical simulation by CFD program Fluent for flow field of hydraulic driving cylinder indicate that the bigger the outer diameter of servo-tube, the smaller the resistance coefficient of variable throttle orifice. The zero position gap of variable throttle orifice could be determined on 0.2 mm in the design. The pressure difference between the upper and nether surfaces of piston was mainly created by the throttle function of fixed throttle orifice. It can be effectively controlled by changing the gap of variable throttle orifice. And the lift force of driving cylinder is able to meet the requirement on the design load. (authors)

Counter-current flow in a vertical to horizontal tube with obstructions

Energy Technology Data Exchange (ETDEWEB)

Tye, P.; Matuszkiewicz, A.; Teyssedou, A. [Institut de Genie Nucleaire, Quebec (Canada)] [and others

1995-09-01

This paper presents experimental results on counter-current flow and flooding in an elbow between a vertical and a horizontal run. The experimental technique used allowed not only the flooding limit to be determined, but also the entire partial delivery region to be studied as well. The influence that various size orifices placed in the horizontal run have on both the delivered liquid flow rates and on the flooding limits is also examined. It is observed that both the flooding limits and the delivered liquid flow rates decrease with decreasing orifice size. Further, it is also observed that the mechanisms that govern the partial delivery of the liquid are significantly different when an orifice is present in the horizontal leg as compared to the case when no orifice is present.

Biomedical device prototype based on small scale hydrodynamic cavitation

Science.gov (United States)

Ghorbani, Morteza; Sozer, Canberk; Alcan, Gokhan; Unel, Mustafa; Ekici, Sinan; Uvet, Huseyin; Koşar, Ali

2018-03-01

This study presents a biomedical device prototype based on small scale hydrodynamic cavitation. The application of small scale hydrodynamic cavitation and its integration to a biomedical device prototype is offered as an important alternative to other techniques, such as ultrasound therapy, and thus constitutes a local, cheap, and energy-efficient solution, for urinary stone therapy and abnormal tissue ablation (e.g., benign prostate hyperplasia (BPH)). The destructive nature of bubbly, cavitating, flows was exploited, and the potential of the prototype was assessed and characterized. Bubbles generated in a small flow restrictive element (micro-orifice) based on hydrodynamic cavitation were utilized for this purpose. The small bubbly, cavitating, flow generator (micro-orifice) was fitted to a small flexible probe, which was actuated with a micromanipulator using fine control. This probe also houses an imaging device for visualization so that the emerging cavitating flow could be locally targeted to the desired spot. In this study, the feasibility of this alternative treatment method and its integration to a device prototype were successfully accomplished.

Biomedical device prototype based on small scale hydrodynamic cavitation

Directory of Open Access Journals (Sweden)

Morteza Ghorbani

2018-03-01

Full Text Available This study presents a biomedical device prototype based on small scale hydrodynamic cavitation. The application of small scale hydrodynamic cavitation and its integration to a biomedical device prototype is offered as an important alternative to other techniques, such as ultrasound therapy, and thus constitutes a local, cheap, and energy-efficient solution, for urinary stone therapy and abnormal tissue ablation (e.g., benign prostate hyperplasia (BPH. The destructive nature of bubbly, cavitating, flows was exploited, and the potential of the prototype was assessed and characterized. Bubbles generated in a small flow restrictive element (micro-orifice based on hydrodynamic cavitation were utilized for this purpose. The small bubbly, cavitating, flow generator (micro-orifice was fitted to a small flexible probe, which was actuated with a micromanipulator using fine control. This probe also houses an imaging device for visualization so that the emerging cavitating flow could be locally targeted to the desired spot. In this study, the feasibility of this alternative treatment method and its integration to a device prototype were successfully accomplished.

Nature of convection-stabilized dc arcs in dual-flow nozzle geometry

International Nuclear Information System (INIS)

Serbetci, I.; Nagamatsu, H.T.

1990-01-01

In this paper, an experimental investigation of the steady-state low-current air arcs in a dual-flow nozzle system is presented. First, the cold flow with no arc as determined for various nozzle geometries, i.e., two- and three-dimensional and orifice nozzles, and nozzle pressure ratios. Supersonic flow separation and oblique and detached shock waves were observed in the flow field. Using a finite-element computer program, the Mach number contours were determined in the flow field for various nozzle-gap spacings and pressure ratios. In addition, the dc arc voltage and current measurements were made for an electrode gap spacing of ∼ 5.5 cm and current levels of I ∼ 25, 50, and 100 A for the three nozzle geometries. The arc voltage and arc power increased rapidly as the flow speed increased from zero to sonic velocity at the nozzle throat. The shock waves in the converging-diverging nozzles resulted in a decrease in the overall resistance by about 15 percent

Next nature : nature changes along with us

NARCIS (Netherlands)

Mensvoort, van K.M.; Grievink, H.J.

2011-01-01

We debate saving nature, we dream about escaping to nature, but rarely do we ask "What is nature?". The Next Nature book radically shifts your notion of nature. Where technology and nature are traditionally seen as opposed, they now appear to merge or even trade places. With our urge to design our

Distortion of plasma due to installation of an orifice in helium discharge positive column

International Nuclear Information System (INIS)

Moslehi- Fard, M.; Bidadi, H.; Khorram, S.; Sobhanian, S.; Muradov, A.H.; Jallali, H.; Shirin Pour, M.

2003-01-01

Complicated potential structure formed at a constriction of positive column of a DC discharge with heated cathode in He at low discharge currents is investigated. According to the potential structure, electrons and ions are accelerated by the electric field and their energy distribution functions acquire multi humped shapes. Additional maximums on distribution function quickly disappear due to collisions and radial losses. The nature of current passing through the potential structure is cleared up on the base of measured distributions. Attempt was made to calculate potential drop in DL tacking into account electron energy distribution variations

Percutaneous transluminal angioplasty of supraaortic vessel

International Nuclear Information System (INIS)

Belli, L.; Puricelli, G.; Cerasano, A.; Cornalba, P.; Rota, L.; Facchinetti, P.

1988-01-01

Sixteen cases are reported of dilatation of supra-aortic vessels; in 14/16 patients the vessel involved was either the subclavian artery or the brachio-cephalich trunk. Special attention is paid to the choice of patients - the ideal one presenting with a single uncalcified lesion, with stenosis more than 50% of diameter; the symptoms have recently appeared, with a significant difference (more than 20 mmHg) in the pressure of the two arms. The technical aspects of the angioplastic procedure are discussed, especially in order to preserve the intracriminal circulation and to limit possible complications. The presence of reversed blood flow in the vertebral artery is extremely important to preserve intracranial circulation from possible embolism; normal flow obtained at the end of the procedure is therefore an useful proof of successful dilatation. The advantages are stressed of dilatation over the surgical technique used in the past. Finally, the importance is emphasized of a correct follow-up and doppler control of supra-aortic circulation

Morphometry of the Myopectineal Orifice

African Journals Online (AJOL)

Hp 630 Dual Core

ГЕНЙФСЧРЖ ОО ЙФСЛР КЗФРЛГХ СЕЕЧФ ЦКФСЧЙК Г ЩЗГНРЗХХ ГЦ ЦКЗ ОСЩЗФ ЗЪЦФЗПЛЦЫ СИ ЦКЗ. ГДЖСПЗР ЦКЗ ПЫСТЗЕЦЛРЗГО СФЛИЛЕЗ ...

Nature and nature values in organic agriculture

DEFF Research Database (Denmark)

Hansen, Lene; Noe, Egon; Højring, Katrine

2006-01-01

The relationship between agriculture and nature is a centra issue in the current agricultural debate. Organic farming has ambitions and a special potential in relation to nature. Consideration for nature is part of the guiding principals of organic farming and many organic farmers are committed...... to protecting natural qualities. However, the issue of nature, landscape, and land use is not straightforward. Nature is an ambiguous concept that involves multiple interests and actors reaching far beyond farmers. The Danish research project ......

Comparison of Inflammatory Response to Transgastric and Transcolonic NOTES

Czech Academy of Sciences Publication Activity Database

Hucl, T.; Beneš, M.; Kočík, M.; Šplíchalová, Alla; Malušková, J.; Krak, M.; Lánská, V.; Heczková, M.; Kieslichová, E.; Oliverius, M.; Špičák, J.

2016-01-01

Roč. 2016, MAY (2016), s. 7320275 ISSN 1687-6121 Institutional support: RVO:61388971 Keywords : TRANSLUMINAL ENDOSCOPIC SURGERY * NOTES TRANSVAGINAL CHOLECYSTECTOMY * PORCINE SURVIVAL MODEL Subject RIV: EE - Microbiology, Virology Impact factor: 1.863, year: 2016

Glacier surge mechanism based on linked cavity configuration of the basal water conduit system

Science.gov (United States)

Kamb, Barclay

1987-08-01

Based on observations of the 1982-1983 surge of Variegated Glacier, Alaska, a model of the surge mechanism is developed in terms of a transition from the normal tunnel configuration of the basal water conduit system to a linked cavity configuration that tends to restrict the flow of water, resulting in increased basal water pressures that cause rapid basal sliding. The linked cavity system consists of basal cavities formed by ice-bedrock separation (cavitation), ˜1 m high and ˜10 m in horizontal dimensions, widely scattered over the glacier bed, and hydraulically linked by narrow connections where separation is minimal (separation gap ≲ 0.1 m). The narrow connections, called orifices, control the water flow through the conduit system; by throttling the flow through the large cavities, the orifices keep the water flux transmitted by the basal water system at normal levels even though the total cavity cross-sectional area (˜200 m2) is much larger than that of a tunnel system (˜10 m2). A physical model of the linked cavity system is formulated in terms of the dimensions of the "typical" cavity and orifice and the numbers of these across the glacier width. The model concentrates on the detailed configuration of the typical orifice and its response to basal water pressure and basal sliding, which determines the water flux carried by the system under given conditions. Configurations are worked out for two idealized orifice types, step orifices that form in the lee of downglacier-facing bedrock steps, and wave orifices that form on the lee slopes of quasisinusoidal bedrock waves and are similar to transverse "N channels." The orifice configurations are obtained from the results of solutions of the basal-sliding-with-separation problem for an ice mass constituting of linear half-space of linear rheology, with nonlinearity introduced by making the viscosity stress-dependent on an intuitive basis. Modification of the orifice shapes by melting of the ice roof due to

Fluid-solid contact vessel having fluid distributors therein

Science.gov (United States)

Jones, Jr., John B.

1980-09-09

Rectangularly-shaped fluid distributors for large diameter, vertical vessels include reinforcers for high heat operation, vertical sides with gas distributing orifices and overhanging, sloped roofs. Devices are provided for cleaning the orifices from a buildup of solid deposits resulting from the reactions in the vessel.

Air-water screen

Energy Technology Data Exchange (ETDEWEB)

Prokopov, O.I.; Kutepov, A.I.

1980-12-08

The air-water screen based on inventor's certificate No. 577364 contains horizontal water and air lines with water and air nozzles. The air line is situated inside the water line eccentrically and contracts it in the area of the nozzle, whose orifices are situated along the line of contact, while the orifices of the water nozzle are situated symmetrically relative to the air orifices and are located at an acute angle to them. To raise the protective properties, on the end of the water line is a lateral nozzle water distributor is an additional nozzle, connected to this container.

Performance comparison of air-source heat pump water heater with different expansion devices

International Nuclear Information System (INIS)

Peng, Jing-Wei; Li, Hui; Zhang, Chun-Lu

2016-01-01

Highlights: • An air-source heat pump water heater model was developed and validated. • System performance with EEV, capillary tube or short tube orifice were compared. • Short tube orifice is more suitable for heat pump water heater than capillary tube. - Abstract: Air source heat pump water heater (ASHPWH) is designed to work under wide operating conditions. Therefore, both the system and components require higher reliability and stability than ordinary heat pump air-conditioning systems. In this paper, a quasi-steady-state system model of ASHPWH using electronic expansion valve (EEV), capillary tube or short tube orifice as expansion device is developed and validated by a prototype using R134a and scroll compressor, by which the system performance is evaluated and compared at varying water temperature and different ambient temperature. Flow characteristics of those three expansion devices in ASHPWH are comparatively analyzed. Results show that the EEV throttling system performs best. Compared with capillary tube, flow characteristics of short tube orifice are closer to that of EEV and therefore more suitable for ASHPWH. Reliability concern of liquid carryover to the compressor in the system using short tube orifice is investigated as well. Higher superheat or less system refrigerant charge could help mitigate the risk.

The role of atherectomy in the treatment of lower extremity peripheral artery disease

Science.gov (United States)

2012-01-01

Background The incidence of lower extremity peripheral artery disease (LE-PAD) continues to increase and associated morbidity remains high. Despite the significant development of percutaneous revascularization strategies, over the past decade, LE-PAD still represents a unique challenge for interventional cardiologists and vascular surgeons. Method Typical features of atherosclerosis that affects peripheral vascular bed (diffuse nature, poor distal runoff, critical limb ischemia, chronic total occlusion) contribute to the disappointing results of traditional percutaneous transluminal angioplasty (PTA). New technologies have been developed in attempt to improve the safety and effectiveness of percutaneous revascularization. Among these, atherectomy, debulking and removing atherosclerotic plaque, offers the potential advantage of eliminating stretch on arterial walls and reducing rates of restenosis. Conclusions This review summarizes the features and the current applications of new debulking devices. PMID:23173800

The Nature of Natural Hazards Communication (Invited)

Science.gov (United States)

Kontar, Y. Y.

2013-12-01

Some of the many issues of interest to natural hazards professionals include the analysis of proactive approaches to the governance of risk from natural hazards and approaches to broaden the scope of public policies related to the management of risks from natural hazards, as well as including emergency and environmental management, community development and spatial planning related to natural hazards. During the talk we will present results of scientific review, analysis and synthesis, which emphasize same new trends in communication of the natural hazards theories and practices within an up-to-the-minute context of new environmental and climate change issues, new technologies, and a new focus on resiliency. The presentation is divided into five sections that focus on natural hazards communication in terms of education, risk management, public discourse, engaging the public, theoretical perspectives, and new media. It includes results of case studies and best practices. It delves into natural hazards communication theories, including diffusion, argumentation, and constructivism, to name a few. The presentation will provide information about: (1) A manual of natural hazards communication for scientists, policymakers, and media; (2) An up-to-the-minute context of environmental hazards, new technologies & political landscape; (3) A work by natural hazards scientists for geoscientists working with social scientists and communication principles; (4) A work underpinned by key natural hazards communication theories and interspersed with pragmatic solutions; (5) A work that crosses traditional natural hazards boundaries: international, interdisciplinary, theoretical/applied. We will further explore how spatial planning can contribute to risk governance by influencing the occupation of natural hazard-prone areas, and review the central role of emergency management in risk policy. The goal of this presentation is to contribute to the augmentation of the conceptual framework

Regularities, Natural Patterns and Laws of Nature

Directory of Open Access Journals (Sweden)

Stathis Psillos

2014-02-01

Full Text Available  The goal of this paper is to sketch an empiricist metaphysics of laws of nature. The key idea is that there are regularities without regularity-enforcers. Differently put, there are natural laws without law-makers of a distinct metaphysical kind. This sketch will rely on the concept of a natural pattern and more significantly on the existence of a network of natural patterns in nature. The relation between a regularity and a pattern will be analysed in terms of mereology.  Here is the road map. In section 2, I will briefly discuss the relation between empiricism and metaphysics, aiming to show that an empiricist metaphysics is possible. In section 3, I will offer arguments against stronger metaphysical views of laws. Then, in section 4 I will motivate nomic objectivism. In section 5, I will address the question ‘what is a regularity?’ and will develop a novel answer to it, based on the notion of a natural pattern. In section 6, I will raise the question: ‘what is a law of nature?’, the answer to which will be: a law of nature is a regularity that is characterised by the unity of a natural pattern.

On Small Disturbance Ascent Vent Behavior

Science.gov (United States)

Woronowicz, Michael

2015-01-01

As a spacecraft undergoes ascent in a launch vehicle, its ambient pressure environment transitions from one atmosphere to high vacuum in a matter of a few minutes. Venting of internal cavities is necessary to prevent the buildup of pressure differentials across cavity walls. These pressure differentials are often restricted to low levels to prevent violation of container integrity. Such vents usually consist of fixed orifices, ducts, or combinations of both. Duct conductance behavior is fundamentally different from that for orifices in pressure driven flows governing the launch vehicle ascent depressurization environment. Duct conductance is governed by the average pressure across its length, while orifice conductance is dictated by a pressure ratio. Hence, one cannot define a valid equivalent orifice for a given duct across a range of pressure levels. This presentation discusses development of expressions for these two types of vent elements in the limit of small pressure differentials, explores conditions for their validity, and compares their features regarding ascent depressurization performance.

Collagen turnover in arterial disease

NARCIS (Netherlands)

Sluijter, J.P.G.

2004-01-01

Increased atherosclerotic plaque formation can lead to lumen reduction and finally to lumen obstruction. Percutaneous transluminal angioplasty (PTA) or balloon angioplasty (dilation) are approaches generally used to treat coronary, but also peripheral atherosclerotic disease. Their goal is to

Intraarterial 192Ir high-dose-rate brachytherapy for prophylaxis of restenosis after femoropopliteal percutaneous transluminal angioplasty: the prospective randomized Vienna-2-trial radiotherapy parameters and risk factors analysis

International Nuclear Information System (INIS)

Pokrajac, Boris; Poetter, Richard; Maca, Thomas; Fellner, Claudia; Mittlboeck, Martina; Ahmadi, Ramazanali; Seitz, Wolfgang; Minar, Erich

2000-01-01

Purpose: The aim of the Vienna-2-trial was to compare the restenosis rate of femoropopliteal arteries after percutaneous transluminal angioplasty (PTA) with or without intraarterial high-dose-rate (HDR) brachytherapy (BT) using an 192 Ir source. Materials and Methods: A prospective, randomized trial was conducted from 11/96 to 8/98. A total of 113 patients (63 men, 50 women), with a mean age of 71 years (range, 43-89 years) were included. Inclusion criteria were (1) claudication or critical limb ischemia, (2) de-novo stenosis of 5 cm or more, (3) restenosis after former PTA of any length, and (4) no stent implantation. Patients were randomized after successful PTA for BT vs. no further treatment. A well-balanced patient distribution was achieved for the criteria used for stratification, as there were 'de-novo stenosis vs. restenosis after former PTA', 'stenosis vs. occlusion', 'claudication vs. critical limb ischemia' and above these for 'diabetes vs. nondiabetes'. PTA length was not well balanced between the treatment arms: a PTA length of 4-10 cm was seen in 19 patients in the PTA alone group and in 11 patients in the PTA+BT group, whereas a PTA length of greater than10 cm was seen in 35 patients and 42 patients, respectively. A dose of 12 Gy was prescribed in 3-mm distance from the source axis. According to AAPM recommendations, the dose was 6.8 Gy in 5-mm distance (vessel radius + 2 mm). Primary endpoint of the study was femoropopliteal patency after 6 months. Results: PTA and additional BT were feasible and well tolerated by all 57 pts in this treatment arm. No acute, subacute, and late adverse side effects related to BT were seen after a mean follow up of 12 months (6-24 months) in 107 patients (PTA n = 54; PTA+ BT n = 53). Crude restenosis rate at 6 months was in the PTA arm 54% vs. 28% in the PTA + BT arm (χ 2 test; p 10 cm) showed significant decrease of the restenosis rate, if BT was added. Significant reduction was not achieved in diabetes patients

NOTES performed using multiple ports of entry: Current experience and potential implications for urologic applications.

Science.gov (United States)

Lima, Estevao; Rolanda, Carla; Correia-Pinto, Jorge

2009-05-01

An isolated transgastric port raises serious limitations in performing natural orifice translumenal endoscopic surgery (NOTES) complex procedures in the urology field. In an attempt to overcome these limitations, several solutions has been advanced, such as the hybrid approach (adding a single abdominal port access) or the pure NOTES combined approach (joining multiple natural orifice ports). To review the current state of experimental and clinical results of multiple ports in NOTES, a literature search of PubMed was performed, seeking publications from January 2002 to 2008 on NOTES. In addition, we looked at pertinent abstracts of annual meetings of the American Urological Association, the European Association of Urology, and the World Congress of Endourology from 2007. Multiple ports of entry seem to be necessary, mainly for moderately complex procedures. Thus, we could find studies using the hybrid approach (combination of transgastric or transvaginal access with a single transabdominal port), or using the pure NOTES combined approach (transgastric and transvesical, transvaginal and transcolonic, or transgastric and transvaginal). There is still limited experience in humans using these approaches, and no comparative studies exist to date. It is predictable that for moderately complex procedures, we will need multiple ports, so the transvaginal-transabdominal (hybrid) approach is the most appealing, whereas in a pure NOTES perspective, the transgastric-transvesical approach seems to be the preferred approach. We are waiting for new equipment and instruments that are more appropriate for these novel techniques.

Indexed effective orifice area is a significant predictor of higher mid- and long-term mortality rates following aortic valve replacement in patients with prosthesis-patient mismatch.

Science.gov (United States)

Chen, Jian; Lin, Yiyun; Kang, Bo; Wang, Zhinong

2014-02-01

Prosthesis-patient mismatch (PPM) is defined as a too-small effective orifice area (EOA) of an inserted prosthetic relative to body size, resulting in an abnormally high postoperative gradient. It is unclear, however, whether residual stenosis after aortic valve replacement (AVR) has a negative impact on mid- and long-term survivals. We searched electronic databases, including PubMed, Embase, Medline and the Cochrane controlled trials register, through October 2012, to identify published full-text English studies on the association between PPM and mortality rates. A significant PPM was defined as an indexed EOA (iEOA)<0.85 cm2/m2, and severe PPM as an iEOA<0.65 cm2/m2. Two reviewers independently assessed the studies for inclusion and extracted data. Fourteen observational studies, involving 14 874 patients, met our final inclusion criteria. Meta-analysis demonstrated that PPM significantly increased mid-term (odds ratio [OR] 1.42, 95% confidence interval [CI] 1.19-1.69) and long-term (OR 1.52, 95% CI 1.26-1.84) all-cause mortalities. Subgroup analysis showed that PPM was associated with higher mid- and long-term mortality rates only in younger and predominantly female populations. Risk-adjusted sensitivity analysis showed that severe PPM was associated with reduced survival (adjusted hazard ratio [HR] 1.50, 95% CI 1.24-1.80), whereas moderate PPM was not (adjusted HR 0.96, 95% CI 0.86-1.07). Regardless of severity, however, PPM had a negative effect on survival in patients with impaired ejection fraction (adjusted HR 1.26, 95% CI 1.09-1.47). PPM (iEOA<0.85 cm2/m2) after AVR tended to be associated with increased long-term all-cause mortality in younger patients, females and patients with preoperative left ventricular dysfunction. Severe PPM (iEOA<0.65 cm2/m2) was a significant predictor of reduced long-term survival in all populations undergoing AVR.

Comparison of peak flow velocity through the left ventricular outflow tract and effective orifice area indexed to body surface area in Golden Retriever puppies to predict development of subaortic stenosis in adult dogs.

Science.gov (United States)

Javard, Romain; Bélanger, Marie-Claude; Côté, Etienne; Beauchamp, Guy; Pibarot, Philippe

2014-12-15

To evaluate the usefulness of Doppler-derived peak flow velocity through the left ventricular outflow tract (LVOT Vmax) and effective orifice area indexed to body surface area (EOAi) in puppies to predict development of subaortic stenosis (SAS) in the same dogs as adults. Prospective, longitudinal, observational study. 38 Golden Retrievers. Cardiac auscultation and echocardiography were performed on 2- to 6-month-old puppies, then repeated at 12 to 18 months. Subaortic stenosis was diagnosed when LVOT Vmax was ≥ 2.3 m/s in adult dogs with left basilar systolic murmurs. All puppies with EOAi 2.3 m/s in puppyhood was 63% sensitive and 100% specific for SAS in adulthood. In puppies, LVOT Vmax was more strongly associated with a future diagnosis of SAS (area under the curve [AUC], 0.89) than was EOAi (AUC, 0.80). In puppies, the combination of LVOT Vmax and EOAi yielded slightly higher sensitivity (69%) and specificity (100%) for adult SAS than did LVOT Vmax alone. In unaffected and affected dogs, LVOT Vmax increased significantly from puppyhood to adulthood but EOAi did not. In Golden Retriever puppies, LVOT Vmax > 2.3 m/s and EOAi < 1.46 cm(2)/m(2) were both associated with a diagnosis of SAS at adulthood. The combination of these 2 criteria may result in higher sensitivity for SAS screening. Unlike LVOT Vmax, EOAi did not change during growth in either unaffected Golden Retrievers or those with SAS.

Indirect evidence for a role of a subpopulation of activated neutrophils in the remodelling process after percutaneous coronary intervention

NARCIS (Netherlands)

Costa, MA; de Wit, LEA; de Valk, V.; Serrano, P; Wardeh, AJ; Serruys, PW; Sluiter, W

Aim Leukocytes have been implicated in restenosis following percutaneous transluminal coronary angioplasty. We investigated the link between the activated status of circulating neutrophils and restenosis after angioplasty. Methods and Results The population of 108 patients with single, de novo

Fast leak of a channel filled with helium at a pressure of 2 bars (channel H5)

International Nuclear Information System (INIS)

Bauer, E.; Tribolet, J.

1987-01-01

The loss of seal of a helium-filled channel opening the entire cross section of the front part leads to a fast leak. The channel fills to the upper generatrix of the leak orifice and part of the helium contained in the channel escapes into the circuit. The pressure drop in the reflector can lead to reactor and main pump shutdown. On the other hand, the Cooling Circuit Shutdown Bar circuit pumps remain in operation. This paper evaluates the consequences of an incident of this nature for the reactor and the surrounding experimental zones

Simple fibre based dispersion management for two-photon excited fluorescence imaging through an endoscope

DEFF Research Database (Denmark)

Dimopoulos, Konstantinos; Marti, Dominik; Andersen, Peter E.

2018-01-01

We want to implement two-photon excitation fluorescence microscopy (TPEFM) into endoscopes, since TPEFM can provide relevant biomarkers for cancer staging and grading in hollow organs, endoscopically accessible through natural orifices. However, many obstacles must be overcome, among others...... the delivery of short laser pulses to the distal end of the endoscope. To this avail, we present imaging results using an all-fibre dispersion management scheme in a TPEFM setup. The scheme has been conceived by Jespersen et al. in 20101 and relies on the combination of a single mode fibre with normal...

Nature and nature values in organic agriculture

DEFF Research Database (Denmark)

Hansen, Lene; Noe, Egon; Højring, Katrine

2006-01-01

The relationship between agriculture and nature is a centra issue in the current agricultural debate. Organic farming has ambitions and a special potential in relation to nature. Consideration for nature is part of the guiding principals of organic farming and many organic farmers are committed...

Natural radiation; A radiacao natural

Energy Technology Data Exchange (ETDEWEB)

Feliciano, Vanusa Maria Delage

2016-07-01

Cosmic radiation, as well as cosmogenic radiation, terrestrial radiation, radon and thorium are introduced in this chapter 3. The distribution of natural radiation sources is treated, where the percentage distribution of the contribution relative to exposure to radiation from natural and artificial sources is also included.

Safety and efficacy of recombinant hirudin (CGP 39 393) versus heparin in patients with stable angina undergoing coronary angioplasty

NARCIS (Netherlands)

van den Bos, A. A.; Deckers, J. W.; Heyndrickx, G. R.; Laarman, G. J.; Suryapranata, H.; Zijlstra, F.; Close, P.; Rijnierse, J. J.; Buller, H. R.; Serruys, P. W.

1993-01-01

Enhanced thrombin activity has been associated with acute and long-term complications following balloon angioplasty (percutaneous transluminal coronary angioplasty (PTCA). We evaluated, in a 2-to-1 randomized, double-blind trial, the effects of recombinant hirudin, CGP 39 393, relative to

Safety and efficacy of recombinant Hirudin (CGP 39 393) versus Heparin in patients with stable angina undergoing coronary angioplasty

NARCIS (Netherlands)

A.A. van den Bos (Arjan); G.R. Heyndrickx (Guy); G-J. Laarman (GertJan); H. Suryapranata (Harry); F. Zijlstra (Felix); P. Close (Philip); J.J.M.M. Rijnierse (Joep); H.R. Büller (Harry); P.W.J.C. Serruys (Patrick); J.W. Deckers (Jaap)

1993-01-01

textabstractBACKGROUND. Enhanced thrombin activity has been associated with acute and long-term complications following balloon angioplasty (percutaneous transluminal coronary angioplasty (PTCA). We evaluated, in a 2-to-1 randomized, double-blind trial, the effects of recombinant hirudin, CGP 39

Hemodynamic Measurements for the Selection of Patients With Renal Artery Stenosis: A Systematic Review

NARCIS (Netherlands)

van Brussel, Peter M.; van de Hoef, Tim P.; de Winter, Robbert J.; Vogt, Liffert; van den Born, Bert-Jan

2017-01-01

Interventions targeting renal artery stenoses have been shown to lower blood pressure and preserve renal function. In recent studies, the efficacy of catheter-based percutaneous transluminal renal angioplasty with stent placement has been called into question. In the identification of functional

Natural Colorants: Food Colorants from Natural Sources.

Science.gov (United States)

Sigurdson, Gregory T; Tang, Peipei; Giusti, M Mónica

2017-02-28

The color of food is often associated with the flavor, safety, and nutritional value of the product. Synthetic food colorants have been used because of their high stability and low cost. However, consumer perception and demand have driven the replacement of synthetic colorants with naturally derived alternatives. Natural pigment applications can be limited by lower stability, weaker tinctorial strength, interactions with food ingredients, and inability to match desired hues. Therefore, no single naturally derived colorant can serve as a universal alternative for a specified synthetic colorant in all applications. This review summarizes major environmental and biological sources for natural colorants as well as nature-identical counterparts. Chemical characteristics of prevalent pigments, including anthocyanins, carotenoids, betalains, and chlorophylls, are described. The possible applications and hues (warm, cool, and achromatic) of currently used natural pigments, such as anthocyanins as red and blue colorants, and possible future alternatives, such as purple violacein and red pyranoanthocyanins, are also discussed.

Modelling and Experimental Investigation of an Active Damper

Directory of Open Access Journals (Sweden)

Rafael Luís Teixeira

2006-01-01

Full Text Available This paper presents a validation methodology of the dynamic behavior of an active viscous damper. The damper has two flexible metallic bellows connected to a rigid reservoir filled with fluid. When one of the bellows is connected to a vibrating structure a periodic flow passes through a variable internal orifice and the damping effect is produced. The size of the orifice is adjusted by a controlled linear piezoelectric actuator that positions the conical core into a conical cavity. The device finite element structural model consists of the valve body and its conical core that are assumed rigid and the flexible bellows are represented by two pistons with elastic suspensions. The flow developed inside the damper is modeled considering the fluid-structure interation, using the Lagrangean-Eulerian formulation. To validate the proposed model a prototype was constructed and experimental tests and numerical simulations are accomplished in the time domain, applying harmonic excitations. The results are compared using curves that relate the damping coefficient with the orifice size and with the input velocity applied at the bellows face. However, for the proper control design and system operation, the direct use of the finite element model becomes unviable due to its high computational time. Then, a reduced second order discrete dynamic model for the damper was developed. The model parameters are identified by analysis in the frequency domain, using impulsive excitation force, for constant and variable orifice sizes. At low excitation frequencies, the damper prototype behaves like a single degree of freedom system which damping factor changes with the orifice size A fuzzy controller was designed and it generates the orifice reference size associated to the desired damping factor. The active system presented better performance when compared to the passive one.

Mixing and NO(x) Emission Calculations of Confined Reacting Jet Flows in a Cylindrical Duct

Science.gov (United States)

Holdeman, James D. (Technical Monitor); Oechsle, Victor L.

2003-01-01

Rapid mixing of cold lateral jets with hot cross-stream flows in confined configurations is of practical interest in gas turbine combustors as it strongly affects combustor exit temperature quality, and gaseous emissions in for example rich-lean combustion. It is therefore important to further improve our fundamental understanding of the important processes of dilution jet mixing especially when the injected jet mass flow rate exceeds that of the cross-stream. The results reported in this report describe some of the main flow characteristics which develop in the mixing process in a cylindrical duct. A 3-dimensional tool has been used to predict the mixing flow field characteristics and NOx emission in a quench section of an RQL combustor, Eighteen configurations have been analyzed in a circular geometry in a fully reacting environment simulating the operating condition of an actual RQL gas turbine combustion liner. The evaluation matrix was constructed by varying three parameters: 1) jet-to-mainstream momentum-flux ratio (J), 2) orifice shape or orifice aspect ratio, and 3) slot slant angle. The results indicate that the mixing flow field significantly varies with the value of the jet penetration and subsequently, slanting elongated slots generally improve the mixing uniformity at high J conditions. Round orifices produce more uniform mixing and low NO(x) emissions at low J due to the strong and adequate jet penetration. No significant correlation was found between the NO(x) production rates and the mixing deviation parameters, however, strong correlation was found between NO(x) formation and jet penetration. In the computational results, most of the NO(x) formation occurred behind the orifice starting at the orifice wake region. Additional NO(x) is formed upstream of the orifice in certain configurations with high J conditions due to the upstream recirculation.

Mother natural: Motivations and associations for consuming natural foods.

Science.gov (United States)

Moscato, Emily M; Machin, Jane E

2018-02-01

Natural is perceived as innately positive and is a widely sought-after attribute in food products. The natural food industry continues to grow in response to rising consumer demand. This qualitative study explored mothers' motivations for purchasing and consuming natural food products for themselves and their families. Mothers are an important population because of their disproportionate influence on household food consumption. We employed participant photography and a series of three weekly focus groups to derive a rich understanding of the activities surrounding and motivations behind seeking natural in everyday buying decisions. Five major themes were identified. First, natural nurtures well-being: physical, psychological, social, and emotional health. Second, natural behaves "supernaturally," allowing positive attributes to be transmitted from the source to the recipient. Third, natural is associated with authenticity, providing a sense of trust, transparency, and control. Fourth, consuming natural reinforces the socially constructed idea of a good mother. Lastly, the preference for natural does not always translate into purchase; mothers face compromises because of conflicting priorities and resources. Understanding mothers' multiple motivations provides deeper insight into the attraction for natural products. The findings have application in positioning interventions for more nutritional eating and revising regulations on the food label natural. Copyright © 2017 Elsevier Ltd. All rights reserved.

Renal sympathetic denervation: MDCT evaluation of the renal arteries.

LENUS (Irish Health Repository)

Hutchinson, Barry D

2013-08-01

Percutaneous transluminal renal sympathetic denervation is a new treatment of refractory systemic hypertension. The purpose of this study was to assess the clinical utility of MDCT to evaluate the anatomic configuration of the renal arteries in the context of renal sympathetic denervation.

Femoral artery recanalisation with percutaneous angioplasty and segmentally enclosed plasminogen activator

DEFF Research Database (Denmark)

Jørgensen, B; Tønnesen, K H; Bülow, J

1989-01-01

To establish whether re-occlusion of the femoral artery could be prevented, in 6 consecutive patients undergoing percutaneous transluminal angioplasty (PTA) for superficial femoral artery occlusion the recanalised segment was isolated, with a 7-French double-balloon catheter. 5 mg recombined huma...

Simulation of air velocity in a vertical perforated air distributor

Science.gov (United States)

Ngu, T. N. W.; Chu, C. M.; Janaun, J. A.

2016-06-01

Perforated pipes are utilized to divide a fluid flow into several smaller streams. Uniform flow distribution requirement is of great concern in engineering applications because it has significant influence on the performance of fluidic devices. For industrial applications, it is crucial to provide a uniform velocity distribution through orifices. In this research, flow distribution patterns of a closed-end multiple outlet pipe standing vertically for air delivery in the horizontal direction was simulated. Computational Fluid Dynamics (CFD), a tool of research for enhancing and understanding design was used as the simulator and the drawing software SolidWorks was used for geometry setup. The main purpose of this work is to establish the influence of size of orifices, intervals between outlets, and the length of tube in order to attain uniformity of exit flows through a multi outlet perforated tube. However, due to the gravitational effect, the compactness of paddy increases gradually from top to bottom of dryer, uniform flow pattern was aimed for top orifices and larger flow for bottom orifices.

A pulse tube cryocooler with a cold reservoir

Science.gov (United States)

Zhang, X. B.; Zhang, K. H.; Qiu, L. M.; Gan, Z. H.; Shen, X.; Xiang, S. J.

2013-02-01

Phase difference between pressure wave and mass flow is decisive to the cooling capacity of regenerative cryocoolers. Unlike the direct phase shifting using a piston or displacer in conventional Stirling or GM cryocoolers, the pulse tube cyocooler (PTC) indirectly adjusts the cold phase due to the absence of moving parts at the cold end. The present paper proposed and validated theoretically and experimentally a novel configuration of PTC, termed cold reservoir PTC, in which a reservoir together with an adjustable orifice is connected to the cold end of the pulse tube. The impedance from the additional orifice to the cold end helps to increase the mass flow in phase with the pressure wave at the cold end. Theoretical analyses with the linear model for the orifice and double-inlet PTCs indicate that the cooling performance can be improved by introducing the cold reservoir. The preliminary experiments with a home-made single-stage GM PTC further validated the results on the premise of minor opening of the cold-end orifice.

Application of X-ray micro-computed tomography on high-speed cavitating diesel fuel flows

Energy Technology Data Exchange (ETDEWEB)

Mitroglou, N.; Lorenzi, M.; Gavaises, M. [City University London, School of Mathematics Computer Science and Engineering, London (United Kingdom); Santini, M. [University of Bergamo, Department of Engineering, Bergamo (Italy)

2016-11-15

The flow inside a purpose built enlarged single-orifice nozzle replica is quantified using time-averaged X-ray micro-computed tomography (micro-CT) and high-speed shadowgraphy. Results have been obtained at Reynolds and cavitation numbers similar to those of real-size injectors. Good agreement for the cavitation extent inside the orifice is found between the micro-CT and the corresponding temporal mean 2D cavitation image, as captured by the high-speed camera. However, the internal 3D structure of the developing cavitation cloud reveals a hollow vapour cloud ring formed at the hole entrance and extending only at the lower part of the hole due to the asymmetric flow entry. Moreover, the cavitation volume fraction exhibits a significant gradient along the orifice volume. The cavitation number and the needle valve lift seem to be the most influential operating parameters, while the Reynolds number seems to have only small effect for the range of values tested. Overall, the study demonstrates that use of micro-CT can be a reliable tool for cavitation in nozzle orifices operating under nominal steady-state conditions. (orig.)

Application of X-ray micro-computed tomography on high-speed cavitating diesel fuel flows

Science.gov (United States)

Mitroglou, N.; Lorenzi, M.; Santini, M.; Gavaises, M.

2016-11-01

The flow inside a purpose built enlarged single-orifice nozzle replica is quantified using time-averaged X-ray micro-computed tomography (micro-CT) and high-speed shadowgraphy. Results have been obtained at Reynolds and cavitation numbers similar to those of real-size injectors. Good agreement for the cavitation extent inside the orifice is found between the micro-CT and the corresponding temporal mean 2D cavitation image, as captured by the high-speed camera. However, the internal 3D structure of the developing cavitation cloud reveals a hollow vapour cloud ring formed at the hole entrance and extending only at the lower part of the hole due to the asymmetric flow entry. Moreover, the cavitation volume fraction exhibits a significant gradient along the orifice volume. The cavitation number and the needle valve lift seem to be the most influential operating parameters, while the Reynolds number seems to have only small effect for the range of values tested. Overall, the study demonstrates that use of micro-CT can be a reliable tool for cavitation in nozzle orifices operating under nominal steady-state conditions.

Application of X-ray micro-computed tomography on high-speed cavitating diesel fuel flows

International Nuclear Information System (INIS)

Mitroglou, N.; Lorenzi, M.; Gavaises, M.; Santini, M.

2016-01-01

The flow inside a purpose built enlarged single-orifice nozzle replica is quantified using time-averaged X-ray micro-computed tomography (micro-CT) and high-speed shadowgraphy. Results have been obtained at Reynolds and cavitation numbers similar to those of real-size injectors. Good agreement for the cavitation extent inside the orifice is found between the micro-CT and the corresponding temporal mean 2D cavitation image, as captured by the high-speed camera. However, the internal 3D structure of the developing cavitation cloud reveals a hollow vapour cloud ring formed at the hole entrance and extending only at the lower part of the hole due to the asymmetric flow entry. Moreover, the cavitation volume fraction exhibits a significant gradient along the orifice volume. The cavitation number and the needle valve lift seem to be the most influential operating parameters, while the Reynolds number seems to have only small effect for the range of values tested. Overall, the study demonstrates that use of micro-CT can be a reliable tool for cavitation in nozzle orifices operating under nominal steady-state conditions. (orig.)

Control rod driving hydraulic pressure device

International Nuclear Information System (INIS)

Ogawa, Masahide.

1993-01-01

The present invention concerns a control rod driving hydraulic device of a BWR type reactor, and provides an improvement for a means for supplying mechanical seal flashing water of a pump. That is, a mechanical seal flashing pipeline is branched at the downstream of a pressure-reducing orifice and connected to a minimum flow pipeline. With such a constitution, the minimum flow pipeline is connected to a minimum flow pipeline of an auxiliary pump at the downstream of the pressure-reducing orifice and returned to a suction pipeline of the pump. Pressure at the downstream of the pressure-reducing orifice is set, in the orifice, to a pressure required for mechanical seal flashing. Accordingly, the mechanical seal flashing pipeline is connected and a part of minimum flow rate is utilized, thereby enabling to cool mechanical seals. As a result, flow rate of the mechanical flashing water which has been flown out can be saved. The exhaustion amount from the pump can be reduced, to decrease the shaft power and reduce the capacity of the motor. (I.S.)

Hydrodynamic Cavitation-Assisted Synthesis of Nanocalcite

Directory of Open Access Journals (Sweden)

Shirish H. Sonawane

2010-01-01

Full Text Available A systematic study was made on the synthesis of nanocalcite using a hydrodynamic cavitation reactor. The effects of various parameters such as diameter and geometry of orifice, CO2 flow rate, and Ca(OH2 concentration were investigated. It was observed that the orifice diameter and its geometry had significant effect on the carbonation process. The reaction rate was significantly faster than that observed in a conventional carbonation process. The particle size was significantly affected by the reactor geometry. The results showed that an orifice with 5 holes of 1 mm size resulted in the particle size reduction to 37 nm. The experimental investigation reveals that hydrodynamic cavitation may be more energy efficient.

Focusing liquid microjets with nozzles

International Nuclear Information System (INIS)

Acero, A J; Ferrera, C; Montanero, J M; Gañán-Calvo, A M

2012-01-01

The stability of flow focusing taking place in a converging–diverging nozzle, as well as the size of the resulting microjets, is examined experimentally in this paper. The results obtained in most aspects of the problem are similar to those of the classical plate-orifice configuration. There is, however, a notable difference between flow focusing in nozzles and in the plate-orifice configuration. In the former case, the liquid meniscus oscillates laterally (global whipping) for a significant area of the control parameter plane, a phenomenon never observed when focusing with the plate-orifice configuration. Global whipping may constitute an important drawback of flow focusing with nozzles because it reduces the robustness of the technique. (paper)

A laser-induced-fluorescence visualization study of transverse, sonic fuel injection in a nonreacting supersonic combustor

Science.gov (United States)

Mcdaniel, J. C.; Graves, J., Jr.

1986-01-01

The present paper reports work which has been conducted in the first phase of a research program which is to provide a data base of spatially-resolved measurements in nonreacting supersonic combustors. In the measurements, a nonintrusive diagnostic technique based on the utilization of laser-induced fluorescence (LIF) is employed. The reported work had the objective to conduct LIF visualization studies of the injection of a simulated fuel into a Mach 2.07 airstream for comparison with corresponding numerical calculations. Attention is given to injection from a single orifice into a constant-area duct, injection from a single orifice behind a rearward-facing step, and injection from staged orifices behind a rearward-facing step.

Super Natural II--a database of natural products.

Science.gov (United States)

Banerjee, Priyanka; Erehman, Jevgeni; Gohlke, Björn-Oliver; Wilhelm, Thomas; Preissner, Robert; Dunkel, Mathias

2015-01-01

Natural products play a significant role in drug discovery and development. Many topological pharmacophore patterns are common between natural products and commercial drugs. A better understanding of the specific physicochemical and structural features of natural products is important for corresponding drug development. Several encyclopedias of natural compounds have been composed, but the information remains scattered or not freely available. The first version of the Supernatural database containing ∼ 50,000 compounds was published in 2006 to face these challenges. Here we present a new, updated and expanded version of natural product database, Super Natural II (http://bioinformatics.charite.de/supernatural), comprising ∼ 326,000 molecules. It provides all corresponding 2D structures, the most important structural and physicochemical properties, the predicted toxicity class for ∼ 170,000 compounds and the vendor information for the vast majority of compounds. The new version allows a template-based search for similar compounds as well as a search for compound names, vendors, specific physical properties or any substructures. Super Natural II also provides information about the pathways associated with synthesis and degradation of the natural products, as well as their mechanism of action with respect to structurally similar drugs and their target proteins. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Natural gas

Energy Technology Data Exchange (ETDEWEB)

Fraser, J W

1967-08-01

This report on the natural gas industry of Canada includes: composition and uses of natural gas, production statistics, exploration and development, reserve estimates, natural gas processing, transportation, and marketing. For the Canadian natural gas industry, 1966 was a year of moderate expansion in all phases, with a strong demand continuing for sulfur and liquid hydrocarbons produced as by-products of gas processing. Value of natural gas production increased to $199 million and ranked sixth in terms of value of mineral ouput in Canada. Currently, natural gas provides over 70% of Canada's energy requirements. Proved remaining marketable reserves are estimated to be in excess of a 29-yr supply.

40 CFR Appendix B to Part 75 - Quality Assurance and Quality Control Procedures

Science.gov (United States)

2010-07-01

...-, nozzle-, or venturi-type fuel flowmeter under section 2.1.6 of appendix D to this part. These procedures... procedures for inspection of the primary element (i.e., orifice, venturi, or nozzle) of an orifice-, venturi... bypass stack, each of which has a certified flow monitor (e.g., a unit with a wet SO2 scrubber...

Automatic coolant flow control device for a nuclear reactor assembly

Science.gov (United States)

Hutter, Ernest

1986-01-01

A device which controls coolant flow through a nuclear reactor assembly comprises a baffle means at the exit end of said assembly having a plurality of orifices, and a bimetallic member in operative relation to the baffle means such that at increased temperatures said bimetallic member deforms to unblock some of said orifices and allow increased coolant flow therethrough.

Hydraulic servo control spool valve

Science.gov (United States)

Miller, Donald M.

1983-01-01

A servo operated spool valve having a fixed sleeve and axially movable spool. The sleeve is machined in two halves to form a long, narrow tapered orifice slot across which a transverse wall of the spool is positioned. The axial position of the spool wall along the slot regulates the open orifice area with extreme precision.

Steady flow torques in a servo motor operated rotary directional control valve

International Nuclear Information System (INIS)

Wang, He; Gong, Guofang; Zhou, Hongbin; Wang, Wei

2016-01-01

Highlights: • A novel servo motor operated rotary directional control valve is proposed. • Steady flow torque is a crucial issue that affects rotary valve performance. • Steady flow torque is analyzed on the aspects of theory, simulation and experiment. • Change law of the steady flow torque with spool rotation angle is explored. • Effect of pressure drop and flow rate on the steady flow torque is studied. - Abstract: In this paper, a servo motor operated rotary directional control valve is proposed, and a systematic analysis of steady flow torques in this valve is provided by theoretical calculation, CFD simulation and experimental test. In the analysis, spool rotation angle corresponding to the maximum orifice opening is tagged as 0°. Over a complete change cycle of the orifice, the range of spool rotation angle is symmetric about 0°. The results show that the direction of steady flow torques in this valve is always the direction of orifice closing. The steady flow torques serve as resistances to the spool rotation when the orifice opening increases, while impetuses to the spool rotation when the orifice opening decreases. At a certain pressure drop or flow rate, steady flow torques are approximately equal and opposite when at spool rotation angles which are symmetric about 0°. When the spool rotates from 0°, at a certain pressure drop, their values increase first then decrease with the spool rotation and reach their maximum values at an angle corresponding to about 1/2 of the maximum orifice opening, and at a certain flow rate, their values increase with the spool rotation. The steady flow torques in this valve are the sums of those in the meter-in and meter-out valve chambers. At a certain spool rotation angle, steady flow torques in the meter-in and meter-out valve chambers are approximately proportional to the pressure drop and the second power of the flow rate through the orifice. Theoretical calculation and CFD simulation can be validated by

One for all? : connectedness to nature, inclusion of nature, environmental identity, and implicit association with nature

NARCIS (Netherlands)

Brügger, A; Kaiser, F.G.; Roczen, N.

2011-01-01

Pleasurable experiences in nature are suspected to promote a personal connection with nature, and subsequently, nature conservation in individuals. Using an Internet-based survey employing a convenience sample of the general population (N = 1,309), we developed a connection-with-nature instrument

A preliminary stability analysis of MYRRHA Primary Heat Exchanger two-phase tube bundle

Energy Technology Data Exchange (ETDEWEB)

Castelliti, Diego [Studiecentrum voor kernenergie – Centre d’étude de l’énergie nucléaire (SCK-CEN), Boeretang 200, Mol (Belgium); GeNERG – DIME/TEC, University of Genova, Via all’Opera Pia 15/a, 16145 Genova (Italy); Lomonaco, Guglielmo, E-mail: guglielmo.lomonaco@unige.it [GeNERG – DIME/TEC, University of Genova, Via all’Opera Pia 15/a, 16145 Genova (Italy); INFN, Via Dodecaneso 33, 16146 Genova (Italy)

2016-08-15

the channel. The stability assessment should take in consideration all the possible reactor operational power levels in order to prove the stable behavior under all operational conditions. The tube bundle stability assessment has been carried out by following a similar procedure used for BWR fuel channels, through a specific RELAP5-3D model representing the PHX and able to evaluate the propagation of a density wave in the tube length. A series of suitable boundary conditions, on both primary and secondary side, and perturbation triggers have been foreseen into the model, so to discover all kind of unstable behavior and to dimension the needed orifice to guarantee the flow stability in all operating conditions. The PHX stability analysis is initially performed on the original tube bundle without the adoption of any stabilizing devices, in order to check the natural behavior of the system. The possible adoption and design of an orifice is then conducted on the basis of this preliminary study. The system response against the various types of instabilities, before the introduction of an orifice, is not completely satisfactory: a stable flow is found within certain specific system parameters ranges. After the introduction of a suitable orifice, the system behavior becomes stable under all operating conditions against all types of two-phase flow instabilities.

A Natural Logic for Natural-Language Knowledge Bases

DEFF Research Database (Denmark)

Andreasen, Troels; Styltsvig, Henrik Bulskov; Jensen, Per Anker

2017-01-01

We describe a natural logic for computational reasoning with a regimented fragment of natural language. The natural logic comes with intuitive inference rules enabling deductions and with an internal graph representation facilitating conceptual path finding between pairs of terms as an approach t...

A Natural Logic for Natural-language Knowledge Bases

DEFF Research Database (Denmark)

Andreasen, Troels; Bulskov, Henrik; Jensen, Per Anker

2017-01-01

We describe a natural logic for computational reasoning with a regimented fragment of natural language. The natural logic comes with intuitive inference rules enabling deductions and with an internal graph representation facilitating conceptual path finding between pairs of terms as an approach t...

[Development of the Feelings toward Nature Scale and relationship between feelings toward nature and proximity to nature].

Science.gov (United States)

Shibata, Seiji

2016-04-01

In the field of environmental psychology, there is rapidly growing interest in the concept of connectivity with nature, describing an individual's sense of being connected with nature. The author developed a new scale for assessing feelings toward nature, including connectedness. Confirmatory factor analysis indicated a five-factor model consisting of restorativeness, oneness, mystery, care, and aversion. Then, the relationships among availability of nature in respondents' neighborhood, age, and each subscale score of the Feelings toward Nature Scale, were analyzed using structural equation modeling. The availability of nature in neighborhoods was assessed using a geographic information system and respondents' subjective evaluations. Results indicate that overall connectedness to nature is weaker as availability of nature decreases, as assessed by subjective evaluation. Results also suggest that aversion toward nature in younger people is relatively stronger than in older generations.

Clinical-pathological-angiographic correlations following transluminal atherectomy

International Nuclear Information System (INIS)

Althaus, S.J.; Maynar, M.; Reyes, R.; Pulido-Duque, J.M.; Casal, G.; Hunter, D.W.; Castaneda-Zuniga, W.R.; Amplatz, K.

1989-01-01

Following percutaneous atherectomy, arterial and catheter diameter relationships were correlated with angiographic and ankle-arm index results. There was a greater amount of tissue removed, improved luminal reconstitution, and ankle-arm index in lesions where the catheter and arterial diameters were equal or within 0.5 mm. Excluding lesions requiring angioplasty, 77% of our lesions had less than 30% residual stenosis; including lesions requiring concomitant angioplasty, the initial overall patency was 93%, with a 1-year patency rate of 92.5%. This study indicates that adequate matching of the atherectomy catheter diameter to the arterial diameter is necessary to optimize tissue removal and clinical results