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Sample records for natural orifices transluminal

  1. [Natural Orifice Transluminal Endoscopic Surgery (NOTES)].

    Science.gov (United States)

    Kim, Yong Sik; Kim, Chul Young; Chun, Hoon Jai

    2008-03-01

    Recently, the field of gastrointestinal endoscopy is developing rapidly. Once limited to the gastroinstestinal lumen, the endoscopic technology is now breaking the barriers and extending its boundary to peritoneal and pleural space. In 2004, Dr. Kalloo, a gastroenterologist, observed intraperitoneal organs of a pig using a conventional endoscope through the stomach wall. Since then, new endoscopic technique of intraperitoneal intervention with transluminal approach named the Natural Orifice Transluminal Endoscopic Surgery or NOTES has been introduced. NOTES reaches the target organ by inserting the endoscope through a natural orifice (e.g. mouth, anus, vagina, urethra) and entering the peritoneal lumen by means of making an incision on the luminal wall. After a series of successful experiences in animal studies, NOTES are now being tried on human subjects. There are still many obstacles to overcome, but bright future for this new technology is expected because of its proposed advantages of less pain, lower complication rate, short recovery time, and scarless access. In this review, we plan to learn about NOTES.

  2. Patient and physician perception of natural orifice transluminal endoscopic appendectomy

    Czech Academy of Sciences Publication Activity Database

    Hucl, T.; Saglová, A.; Beneš, M.; Kocík, M.; Oliverius, M.; Valenta, Zdeněk; Špičák, J.

    2012-01-01

    Roč. 18, č. 15 (2012), s. 1800-1805 ISSN 1007-9327 Institutional research plan: CEZ:AV0Z10300504 Keywords : natural orifice transluminal endoscopic surgery * patient perception * physician perception * appendectomy * laparoscopy Subject RIV: FJ - Surgery incl. Transplants Impact factor: 2.547, year: 2012

  3. Review of transvaginal natural orifice transluminal endoscopic surgery in gynecology

    Directory of Open Access Journals (Sweden)

    Naoyuki Yoshiki

    2017-02-01

    Full Text Available Recent technologic advances in endoscopic instrumentation and optics have allowed the development of a less invasive alternative to conventional laparoscopic surgery. During the past decade, natural orifice transluminal endoscopic surgery (NOTES flourished in the field of general surgery, and it has emerged as a new concept of minimally invasive surgery. NOTES yields access to the abdominal cavity without any incisions on the abdominal wall (scarless surgery, and the natural orifices of the body surface, such as the mouth and the vagina, serve as the gateway to the peritoneal cavity. In gynecology, the vagina of a woman can be considered as an additional route for surgery. Recently, clinical application of transvaginal NOTES has broadened significantly in gynecology. Using transvaginal NOTES by applying the method of single-incision laparoscopic surgery via the vaginal route, not only adnexal surgery and hysterectomy, but also myomectomy and oncologic surgery could be performed safely and effectively in selected patients. In future, further studies should be conducted to evaluate the true clinical feasibility and safety of transvaginal NOTES.

  4. Robot-assisted natural orifice transluminal endoscopic surgery for hysterectomy.

    Science.gov (United States)

    Lee, Chyi-Long; Wu, Kai-Yun; Su, Hsuan; Han, Chien-Min; Huang, Chen-Ying; Yen, Chih-Feng

    2015-12-01

    To describe the surgical procedures of robot-assisted natural orifice transluminal endoscopic surgery (NOTES) for hysterectomy and to evaluate its feasibility. From December 2014 to February 2015, four patients with benign diseases who were eligible for robot-assisted NOTES at Chang Gung Memorial Hospital were recruited to this study. Intraoperative and postoperative surgical outcomes were evaluated. Robot-assisted NOTES hysterectomy was successfully performed in all these patients. None of the patients had vaginal delivery, with two being nulliparous. The mean ± standard error of the mean uterine weight was 365.5 ± 69.2 g, the mean operative time was 198.8 ± 39.0 minutes, the mean docking time was 38.3 ± 2.4 minutes, the mean blood loss was 180.0 ± 56.1 mL, and the mean postoperative hospital stay was 2.5 ± 0.3 days. The final pathologic diagnoses were adenomyosis and/or leiomyomas. The novel robot-assisted NOTES technology created scarless skin wounds. More importantly, the device allows the surgeon to reach deeper places to achieve hemostasis, and perform surgery on larger tumors using the curved cannulae-wristed instrument. However, its implementation is limited by the lack of appropriate instrumentation, which requires further development and break through. At this stage, robot-assisted NOTES is only useful for limited applications in highly selected patients. Copyright © 2015. Published by Elsevier B.V.

  5. Natural orifice transluminal endoscopic surgery vs laparoscopic ovariectomy: Complications and inflammatory response

    Czech Academy of Sciences Publication Activity Database

    Martínek, J.; Ryska, O.; Filípková, T.; Doležel, R.; Juhás, Štefan; Motlík, Jan; Holubová, Monika; Nosek, V.; Rotnáglová, B.; Zavoral, M.; Ryska, M.

    2012-01-01

    Roč. 18, č. 27 (2012), s. 3558-3564 ISSN 1007-9327 Institutional research plan: CEZ:AV0Z50450515 Keywords : Natural orifice transluminal endoscopic surgery * Laparoscopy * Ovariectomy Subject RIV: FP - Other Medical Disciplines Impact factor: 2.547, year: 2012

  6. Technical skill set training in natural orifice transluminal endoscopic surgery: how should we approach it?

    LENUS (Irish Health Repository)

    Nugent, Emmeline

    2011-03-01

    The boundaries in minimally invasive techniques are continually being pushed further. Recent years have brought new and exciting changes with the advent of natural orifice transluminal endoscopic surgery. With the evolution of this field of surgery come challenges in the development of new instruments and the actual steps of the procedure. Included in these challenges is the idea of developing a proficiency-based curriculum for training.

  7. In vitro comparison and evaluation of seven gastric closure modalities for natural orifice transluminal endoscopic surgery (NOTES)

    NARCIS (Netherlands)

    Voermans, R. P.; Worm, A. M.; van Berge Henegouwen, M. I.; Breedveld, P.; Bemelman, W. A.; Fockens, P.

    2008-01-01

    BACKGROUND AND STUDY AIMS: Secure transluminal closure is the most fundamental prerequisite for the safe introduction of natural orifice transluminal endoscopic surgery (NOTES). The aim was to compare acute strength of various gastrotomy closure techniques in an in vitro porcine stomach model by

  8. In vivo microrobots for natural orifice transluminal surgery. Current status and future perspectives.

    Science.gov (United States)

    Forgione, A

    2009-06-01

    The possibility to operate inside the peritoneal cavity through small holes performed in hollow organs that is presented by Natural Orifice Transluminal Endoscopic Surgery (NOTES) represents a major paradigm shift in general surgery. While this new approach seems very appealing from patients' perspectives because it eliminates completely abdominal wall aggression and promises to reduce postoperative pain, it is very challenging for surgeons because of the major constraints imposed by both the mode of access and the limited technology currently available. For this reason NOTES applications at the present time are performed by only a few surgeons and mainly to perform non-complex procedures. While new devices are under development, many of them are trying mainly to simply improve current endoscopic platforms and seem not to offer breakthrough solutions. The numerous challenges introduced by natural orifice approaches require a radical shift in the conception of new technologies in order to make this emerging operative access safe and reproducible. The convergence of several enabling technologies in the field of miniaturization, communication and micro-mechatronics brings the possibility to realize on a large scale the revolutionary concept of miniature in vivo co-operative robots. These robots provide vision and task assistance without the constraints of the entry incision and have been shown in experimental settings to possess many qualities that could be ideal to partner with Natural Orifice Surgery. This article explores the current status of microrobotics as well as presents potential future scenarios of their applications in NOTES.

  9. A review on the status of natural orifice transluminal endoscopic surgery (NOTES cholecystectomy: techniques and challenges

    Directory of Open Access Journals (Sweden)

    Michael C Meadows

    2010-09-01

    Full Text Available Michael C Meadows1,3, Ronald S Chamberlain1,2,31Department of Surgery, Saint Barnabas Medical Center, Livingston, NJ, USA; 2Department of Surgery, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA; 3Saint George’s University, School of Medicine, West Indies, GrenadaIntroduction: The evolution of techniques for the performance of a cholecystectomy over the last 25 years has been swift. The laparoscopic approach is now the gold standard for removal of the gall bladder and is the most frequently performed minimally invasive procedure globally. Currently in its infancy stage, natural orifice transluminal endoscopy surgery, or NOTES, is purported to be the next leap forward in minimally invasive approaches. The safety, feasibility, and effectiveness of this procedure, as well as the significance of potential benefits to patients beyond current surgical approaches are yet undetermined.Methods: A comprehensive literature search was conducted using PubMed, a search engine ­created by the National Library of Medicine. Keywords used in the search included “natural orifice transluminal endoscopic surgery”, “NOTES”, “cholecystectomy”, “transcolonic”, “transvaginal”, and “transgastric”. The accumulated literature was critically analyzed and reviewed.Results: One-hundred and eighty-six cases of NOTES cholecystectomies have been published to date. Of these, 174 have been performed through a transvaginal approach. The remainder of the procedures were performed transgastrically. There are no published reports of ­transcolonic cholecystectomies performed in humans. Four of 186 cases (2.15% were converted to traditional laparoscopy due to intraoperative complications. No significant complications or mortalities have been reported.Conclusion: NOTES cholecystectomy appears to be a feasible procedure. However, technical, safety, and ethical issues remain relatively unresolved. Besides improved cosmesis, whether additional

  10. Pure natural orifice transluminal endoscopic surgery (NOTES) with ultrasonography-guided transgastric access and over-the-scope-clip closure

    DEFF Research Database (Denmark)

    Donatsky, Anders Meller; Andersen, Luise; Nielsen, Ole Lerberg

    2012-01-01

    Most natural orifice transluminal endoscopic surgery (NOTES) procedures to date rely on the hybrid technique with simultaneous laparoscopic access to protect against access-related complications and to achieve adequate triangulation for dissection. This is done at the cost of the potential benefits...

  11. Embryonal natural orifice transluminal endoscopic surgery treating severe acute pancreatitis complicated by abdominal compartment syndrome.

    Science.gov (United States)

    Zhu, Huiming; Liao, Xiumin; Guo, Shaoqing; Xuong, Gaofei; Jiang, Di; Liu, Yujie

    2014-10-01

    This study aims to estimate the value of embryonal natural orifice transluminal endoscopic surgery (ENOTES) as a treatment for severe acute pancreatitis (SAP) complicated by abdominal compartment syndrome (ACS). The patients who were randomized into ENOTES group and surgery group underwent ENOTES and laparotomy, respectively. The Efficacy and complications of these two treatments were compared. Enterocinesia was observed earlier in patients of ENOTES group than that of surgery group. Acute Physiology and Chronic Health Evaluation II (APACHE II) score of patients in ENOTES group was superior to that of surgery group on the 1st, 3rd and 5th day after treatment (P complications and mortality were observed between two groups (P complications.

  12. Assessing transgastric Natural Orifice Transluminal Endoscopic Surgery prior to clinical implementation

    DEFF Research Database (Denmark)

    Donatsky, Anders Meller

    2014-01-01

    The objective was to investigate whether transgastric Natural Orifice Transluminal Endoscopic Surgery (NOTES) could be implemented safely in clinical practice. The experimental studies proved ultrasonography guided access through the stomach to be feasible and safe without iatrogenic complications...... visualisation of anatomical structures of interest in the diagnostics and staging of upper gastrointestinal cancers. Another problem with TG NOTES is the risk of intra-abdominal infections. Using a multimodal decontamination regimen reduced the rate of intra-abdominal pathology, but the risk of intra......-abdominal abscess formation as a result of contamination from the access route was still present. To reduce this contamination, mouthwash with chlorhexidine was effective in a human randomised study. The same study also found significant higher bacterial load in the stomach of patients using proton pump inhibitor...

  13. Feasibility study of natural orifice transluminal endoscopic surgery inguinal hernia repair.

    Science.gov (United States)

    Sherwinter, Danny A; Eckstein, Jeremy G

    2009-07-01

    A potentially less-invasive technique, transluminal surgery, may reduce or eliminate pain and decrease time to full return of activities after abdominal operations. Inguinal hernia repair is perfectly suited to the transgastric endoscopic approach and has not been previously reported. Our purpose was to evaluate the feasibility of transgastric bilateral inguinal herniorrhaphy (BIH). Feasibility study with a nonsurvival canine model. Under general anesthesia, male mongrel dogs weighing 20 to 30 kg had a dual-channel endoscope introduced into the peritoneal cavity over a percutaneously placed guidewire. An overtube with an insufflation channel was used. Peritoneoscopy was performed, and bilateral deep and superficial inguinal rings were identified. The endoscope was removed, premounted with a 4 x 6 cm acellular human dermal implant and then readvanced intraperitoneally through the overtube. The implant was then deployed across the entire myopectineal orifice and draped over the cord structures. Bioglue was then applied endoscopically, and the implant was attached to the peritoneum. After completion of bilateral repairs, the animals were killed and necropsy performed. Five dogs underwent pure natural orifice transluminal endoscopic surgery (NOTES) intraperitoneal onlay mesh (IPOM) BIH. Accurate placement and adequate myopectineal coverage was accomplished in all subjects. At necropsy no injuries to the major structures were noted but Bioglue misapplication with contamination of unintended sites did occur. Our study involved only a small number of subjects in nonsurvival experiments, and no gastric closure was used. Many of the characteristics of inguinal hernia repair are especially well suited to the transgastric approach. The repair is in line with the transgastric endoscope vector, bilateral defects are adjacent, and the IPOM technique does not require significant manipulation or novel instrumentation.

  14. Success and complication parameters for laparoscopic surgery: a benchmark for natural orifice transluminal endoscopic surgery.

    Science.gov (United States)

    Gutt, C N; Müller-Stich, B P; Reiter, M A

    2009-01-01

    Natural orifice transluminal endoscopic surgery (NOTES) currently represents an issue of particular interest among surgeons and gastroenterologists. The principle of NOTES is the reduction of the operative trauma by using natural orifices of the human body to access the abdominal cavity. Regarding the tendency to further minimization of the surgical trauma, NOTES may be considered as a logical step in the evolution of minimally invasive surgery. Pioneers of this technique regard NOTES as the successor to laparoscopic surgery in enabling surgeons and gastroenterologists to conduct scarless surgery. This might not only lead to better cosmetic results but also enhance the prospect of decreases in wound infections and incisional hernias, as well as reducing operative stress, postoperative immobility, and pain. In this article the authors collect and review the existing literature concerning NOTES and establish a benchmark for the assessment of this new technique by stating results from conventional minimally invasive surgery as the gold standard. It is shown that publications investigating possible advantages or long-term results of NOTES are scarce. However, the investigation and verification of potential advantages and disadvantages represent the most important step in the development of a new technique. Only proven advantages would justify the broad implementation of a new technique in relation to its specific risks. Conventional laparoscopic surgery as the current standard of minimally invasive surgery will be the benchmark for NOTES with regard to most issues. Superiority of NOTES in at least several issues would be the best argument for its further implementation into clinical practice.

  15. NOViSE: a virtual natural orifice transluminal endoscopic surgery simulator.

    Science.gov (United States)

    Korzeniowski, Przemyslaw; Barrow, Alastair; Sodergren, Mikael H; Hald, Niels; Bello, Fernando

    2016-12-01

    Natural orifice transluminal endoscopic surgery (NOTES) is a novel technique in minimally invasive surgery whereby a flexible endoscope is inserted via a natural orifice to gain access to the abdominal cavity, leaving no external scars. This innovative use of flexible endoscopy creates many new challenges and is associated with a steep learning curve for clinicians. We developed NOViSE-the first force-feedback-enabled virtual reality simulator for NOTES training supporting a flexible endoscope. The haptic device is custom-built, and the behaviour of the virtual flexible endoscope is based on an established theoretical framework-the Cosserat theory of elastic rods. We present the application of NOViSE to the simulation of a hybrid trans-gastric cholecystectomy procedure. Preliminary results of face, content and construct validation have previously shown that NOViSE delivers the required level of realism for training of endoscopic manipulation skills specific to NOTES. VR simulation of NOTES procedures can contribute to surgical training and improve the educational experience without putting patients at risk, raising ethical issues or requiring expensive animal or cadaver facilities. In the context of an experimental technique, NOViSE could potentially facilitate NOTES development and contribute to its wider use by keeping practitioners up to date with this novel surgical technique. NOViSE is a first prototype, and the initial results indicate that it provides promising foundations for further development.

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

    Science.gov (United States)

    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.

  17. Embryonic natural orifice transluminal endoscopic surgery in the treatment of severe acute pancreatitis complicated by abdominal compartment syndrome.

    Science.gov (United States)

    Zhu, Hui-Ming; Guo, Shao-Qing; Liao, Xiu-Min; Zhang, Li; Cai, Li

    2015-01-01

    The study aimed to estimate the value of embryonal natural orifice transluminal endoscopic surgery (ENOTES) in treating severe acute pancreatitis (SAP) complicated with abdominal compartment syndrome (ACS). The patients, who were randomized into an ENOTES group and an operative group, underwent ENOTES and laparotomy, respectively. The results and complications of the two groups were compared. Enterocinesia was observed earlier in the ENOTES group than in the operative group. Acute Physiology and Chronic Health Evaluation II (APACHE II) score of patients in the ENOTES group was lower than that of the operative group on the 1st, 3rd and 5th post-operative day (Pcomplications and mortality between the two groups (Pcomplications.

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

    Science.gov (United States)

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

    2010-05-01

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

  19. EFFECTS OF NATURAL ORIFICE SECRETIONS IN PERITONEAL CAVITY IN THE BACKGROUND OF NATURAL ORIFICE TRANSLUMINAL ENDOSCOPIC SURGERY (NOTES AN EXPERIMENTAL STUDY IN ANIMALS

    Directory of Open Access Journals (Sweden)

    Devendra

    2015-03-01

    Full Text Available Natural Orifice Transluminal Endoscopic Surgery (NOTES is a new form of minimally invasive surgery which eliminates traditional skin incisions by accessing internal body cavities through natural orifices. In our experimental animal study, we compared the incidences intraperitoneal abscess formation , culture swab of peritoneal cavity positive for organism, intraperitoneal adhesion formation and mean adhesion score before and after lavaging the portal of entry of albino rat , i.e. transgastric and transvaginal. On vaginal route as a portal of entry into peritoneal cavity , on the 7th day , 66% rats developed abscesses , 88% rats had culture swab positive and 88% rats developed intraperitoneal adhesion (grade - 2 before any cleansing of vaginal cavity with antiseptic solution . Now after lavage with povidone iodine solution, only 11% developed abscesses , 22% were peritoneal swab culture positive and 33% had interbowel and parietal adhesion of (grade 0 - 1. On 21 st day , the complication observed was adhesion formation in pre lavage group of 66% incidence and 16% after vaginal lavage. The incidence of complications were reduced significantly after lavage with antiseptic solution as shown by p values (p<0.01 for abscess formation, p< 0.01 for culture positivity and p< 0.01 for adhesions formation. Also the mean adhesion scoring was significantly reduced (p <0.02 after vaginal lavage on the 7 th day. Gastric route as the portal of entry into the peritoneal cavity, again the same variables were compared on the 7th and the 21st day , but wash was given with antibiotic solution (Cefazolin. On the 7th day , 44% had abscesses, 77% were culture positive and 66% had adhesions (Grade 1 - 2 before gastric lavage with antibiotic solution . After wash of stomach, 11% were culture positive and 44% developed adhesions (Grade 0 - 1. Here, abscess formation (p<0.02 and mean adhesion scoring (p<0.05 were significantly reduced after stomach wash. On the 21st day

  20. Assessment of the therapeutic efficacy and safety of natural orifice transluminal endoscopic surgery in patients with fulminant acute pancreatitis

    Directory of Open Access Journals (Sweden)

    ZHU Huiming

    2013-03-01

    Full Text Available ObjectiveTo evaluate the therapeutic effect of natural orifice transluminal endoscopic surgery (NOTES intervention in a cohort of patients treated for fulminant acute pancreatitis (FAP over a five-year period. MethodsBetween September 2007 and June 2012, 24 patients were treated with NOTES within 72 h of FAP onset and included 18 males and six females between the ages of 21-76 years old. The procedure was performed via the mouth to the stomach wall for penetration into the abdominal cavity and extraction of the inflammatory secretion followed by saline washes and lavage tube placement. Abdominal cavity lavage and peritoneal dialysis were carried out for one week. Outcome measures included abdominal pressure, bowel sounds, serum levels of inflammatory markers (tumor necrosis factor-alpha (TNFα, interleukin (IL-6, and IL-8, recovery time, and APACHE II score Data were analyzed using the Chi-squared test or F-test. ResultsIn 19 patients, the peritoneal effusion fluid volume removed during the NOTES procedure ranged from 200-2100 ml, and involved serous (n=7, blood (n=5, cellulose (n=5, and suppurative (n=2 fluids. In four patients, the lesser omental bursa effusion fluid volume ranged from 460-2500 ml, and involved serous (n=2 and blood (n=2 fluid. Abdominal pressure had decreased by day 2 after the NOTES procedure (8.60±2.65 vs. admission: 29.2±5.6 cm H2O. Intestinal peristalsis (admission: 1.68±1.02 times/minute was resolved by day 6 after the NOTES procedure (4.30±1.75 times/minute. Serum levels of TNFα, IL-6, and IL-8 were decreased significantly after the NOTES procedure (admission vs. day 6, all P<0.01. In addition, APACHE II score decreased after the NOTES procedure (admission: 12.76±6.68 vs. day 6: 6.46±1.84. The cure rate was 95.8%, and only one patient died (due to progressive multiple organ failure. The mean duration of hospital stay was 21.98±7.88 days. ConclusionNOTES intervention with extraction of the inflammatory

  1. IMELDA transvaginal approach to ectopic pregnancy: diagnosis by transvaginal hydrolaparoscopy and treatment by transvaginal natural orifice transluminal endoscopic surgery.

    Science.gov (United States)

    Baekelandt, Jan; Vercammen, Jona

    2017-01-01

    To demonstrate a new minimally invasive approach for the diagnosis and treatment of ectopic pregnancy. Stepwise explanation of the technique using original video footage. Hospital. Since 2014, 15 patients were treated transvaginally for ectopic pregnancy and pregnancy of unknown location (PUL). In case of a diagnosis of ectopic pregnancy on ultrasound, a 2.5-cm colpotomy is made under general anesthesia, and the ectopic pregnancy is treated by transvaginal natural orifice transluminal endoscopic surgery (vNOTES) salpingectomy or salpingostomy. In case of a PUL on ultrasound, transvaginal hydrolaparoscopy (TVHL), an established technique for fertility exploration under local or general anesthesia, is used to investigate. If a tubal pregnancy is confirmed on TVHL, the colpotomy is extended to a 2.5-cm incision, and the ectopic pregnancy is treated transvaginally by vNOTES. If the TVHL investigation of the pelvis is negative (fallopian tubes and ovaries are normal), the procedure is stopped and the patient is followed up further. If the TVHL is inconclusive, the NaCl is drained and CO 2 is insufflated (requiring general anesthesia) through the 4-mm TVHL port to improve visualization. Again, an ectopic pregnancy is then treated by vNOTES, and in case of a negative investigation the procedure is stopped and the patient is followed up further. Successful diagnosis and treatment of ectopic pregnancies. All patients were successfully operated without complications or conversions to standard laparoscopy. Twelve patients were treated by vNOTES for ectopic pregnancy. Three TVHL explorations for PUL were negative, and these patients were followed up; two patients developed a normal intrauterine pregnancy, and the third patient was treated with methotrexate for persistent asymptomatic raised hCG levels. Transvaginal hydrolaparoscopy and vNOTES are complementary techniques enabling gynecologic surgeons to explore PUL and treat ectopic pregnancies via minimally invasive

  2. Cosmetic issues of abdominal surgery: results of an enquiry into possible grounds for a natural orifice transluminal endoscopic surgery (NOTES) approach.

    Science.gov (United States)

    Hagen, M E; Wagner, O J; Christen, D; Morel, P

    2008-07-01

    Decreased scarring is an advantage of minimally invasive surgery. The new experimental technique of natural orifice transluminal surgery (NOTES) aims at totally scarless surgery. We examined the general attitudes of patients and unaffected persons towards scarless surgery. We used a 7-item questionnaire in structured interviews with hospital visitors, following detailed standardized explanation of terms used and of possible complications, to groups of 10 participants, during an "open ward" day. A visual analog scale (VAS) from 1 (none) to 10 (very much) was used for all but one item. Questions concerned the importance of cosmetic results in abdominal surgery, satisfaction regarding existing scars, hypothetical acceptance of increased risk as a trade-off for the absence of scars, and other issues. Data were analyzed for participants overall, and for three age groups and both sexes. 292 participants (male : female 1 : 1; mean age 43 years) completed the questionnaire. Cosmetic issues were rated as important (median 8), but acceptance of existing scars was also high in those affected (median 8, n=68). Approval of scarless surgery decreased with a presumed risk increase (from score 9 down to score 5), and overall an increase in risk of 10 % was judged to be acceptable as a trade-off for total absence of scarring. Younger people tended to be less satisfied with scars, but were also less inclined than older people to accept higher surgical risk in this hypothetical context. People generally seem to favor scarless abdominal surgery, even with some increase in risk.

  3. On-demand endoscopic CO2 insufflation with feedback pressure regulation during natural orifice transluminal endoscopic surgery (NOTES) peritoneoscopy induces minimal hemodynamic and respiratory changes.

    Science.gov (United States)

    Navarro-Ripoll, Ricard; Martínez-Pallí, Graciela; Guarner-Argente, Carlos; Córdova, Henry; Martínez-Zamora, Maria Angels; Comas, Jaume; Rodríguez de Miguel, Cristina; Beltrán, Mireia; Rodríguez-D'Jesús, Antonio; Hernández-Cera, Clara; Llach, Josep; Balust, Jaume; Fernández-Esparrach, Glòria

    2012-08-01

    Endoscopic insufflation has been associated with marked increase in intra-abdominal pressure (IAP) and hemodynamic and respiratory changes during transgastric surgery. To investigate the hemodynamic and respiratory effects during intraperitoneal cavity exploration through 3 different natural orifice transluminal endoscopic surgery (NOTES) access locations compared with laparoscopy. Survival experiments using 40 female pigs randomized to transgastric, transcolonic, transvaginal, and laparoscopic peritoneoscopy. On-demand endoscopic insufflation of CO(2) with feedback pressure regulation was used in NOTES with a maximum pressure of 14 mm Hg. In the laparoscopy group, the IAP was maintained at 14 mm Hg. NOTES procedures were performed by an endoscopist (with the assistance of a gynecologist in the transvaginal group and a second endoscopist in the transgastric and transrectal groups) and laparoscopy by 2 surgeons. Invasive hemodynamic and respiratory data. Blood samples were drawn for gas analyses. All experiments except one in the transrectal group were completed. The IAP was significantly lower in all NOTES groups compared with the laparoscopy group. A significant increase in mean systemic arterial blood pressure was observed in the laparoscopy group at 15 and 30 minutes of intraperitoneal cavity exploration, but it remained unchanged during all NOTES procedures. An increase in airway pressures was observed at 15 and 30 minutes of peritoneoscopy in the animals undergoing laparoscopy, whereas those parameters remained unchanged in the NOTES groups. The laparoscopy group showed a significant impairment in pulmonary gas exchange (decrease in Pao(2), increase in Paco(2), and decrease in arterial pH) after 30 minutes of peritoneoscopy, whereas only a slight increase in Paco(2) was observed in the transrectal and transvaginal groups. Healthy animal model. On-demand endoscopic insufflation of CO(2) with feedback pressure regulation can minimize the risk of hemodynamic and

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

    Science.gov (United States)

    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

  5. Natural Orifice Transesophageal Endoscopic Surgery: State of the Art

    Directory of Open Access Journals (Sweden)

    João Moreira-Pinto

    2012-01-01

    Full Text Available The main goal of Natural Orifice Transluminal Endoscopic Surgery (NOTES is performing surgery avoiding skin incisions. Theoretical advantages of NOTES include decreased postoperative pain, reduction/elimination of general anesthesia, improved cosmetic outcomes, elimination of skin incision-related complications such as wound infections and hernias, and increased overall patient satisfaction. Although various forms of port creation to accomplish thoracic NOTES procedures have been proposed, transesophageal NOTES has been shown to be the most reliable one. The evolution of endoscopic submucosal transesophageal access resulted in the development of per-oral endoscopic myotomy (POEM, which had a fast transition to clinical practice. The authors present a review of the current state of the art concerning transesophageal NOTES, looking at its potential for diagnostic and therapeutic interventions as well as the hurdles yet to be overcome.

  6. A novel, new robotic platform for natural orifice distal pancreatectomy.

    Science.gov (United States)

    Thakkar, Shyam; Awad, Michael; Gurram, Krishna C; Tully, Steven; Wright, Cornell; Sanan, Siddharth; Choset, Howie

    2015-06-01

    Laparoendoscopic technology has revolutionized the practice of surgery; however, surgeons have not widely accepted laparoscopic techniques for pancreatic surgeries due to the complexity of the operation. Natural orifice transluminal endoscopic surgery (NOTES) offers a great new potential for pancreatic procedures, with early data showing benefits of reduced visible scarring and the potential for decreased wound infections, hernias, pain, and postoperative complications. However, there are significant limitations to the currently used flexible endoscopy tools, including a diminished visual field, spatial orientation and tissue manipulation issues, and 2-dimensional visual feedback. We have adopted a novel snake-like robot, the minimally invasive cardiac surgery (MICS) robot, which addresses these issues. In the current pilot study, the MICS robot was evaluated for transrectal distal pancreas exploration and resection in 2 nonsurvival porcine models. Abdominal navigation and accessing the pancreas was investigated in the first pig, and based on its success, pancreas resection was studied in pig 2. The MICS robot was successful in accessing and visualizing the right upper, left upper, and left lower quadrants of the abdomen in pig 1 and was able to perform a successful complex NOTES procedure with distal pancreas resection in pig 2, with only minimal laparoscopic retraction assistance. In conclusion, preliminary results showing the MICS robot in natural orifice distal pancreatectomy are positive. Enhancements to optics and instrumentation will help further increase the usability in pancreatic interventions. Future indications may include transgastric NOTES approaches, endoluminal procedures, and single-port applications. © The Author(s) 2014.

  7. 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

  8. International Conference on Natural Orifice Transluminal Endoscopic Surgery (NOTES)

    Science.gov (United States)

    2006-06-01

    n = 1; 15) Male (« = 7) Female (n = 9) Mesenteric thrombosis (n = 6) Gardner’s syndrome (n = 2) Pseudoobstruction (/; = 2) Trauma (n = 2...but it was stopped 1 week before the operation. There were also two cases of pneumonia, one case of deep vein thrombosis in the lower limb, and...through the peritoneum, especially in nonobese patients (Figs. 4 and 5). The inferior mesenteric artery originates from the anterior wall of the

  9. Developing Modularized Virtual Reality Simulators for Natural Orifice Translumenal Endoscopic Surgery (NOTES).

    Science.gov (United States)

    Ahn, Woojin; Dorozhkin, Denis; Schwaitzberg, Steven; Jones, Daniel B; De, Suvranu

    2016-01-01

    Natural orifice translumenal endoscopic surgery (NOTES) procedures are rapidly being developed in diverse surgical fields. We are developing a Virtual Translumenal Endoscopic Surgery Trainer (VTEST™) built on a modularized platform that facilitates rapid development of virtual reality (VR) NOTES simulators. Both the hardware interface and software components consist of independent reusable and customizable modules. The developed modules are integrated to build a VR-NOTES simulator for training in the hybrid transvaginal NOTES cholecystectomy. The simulator was demonstrated and evaluated by expert NOTES surgeons at the 2015 Natural Orifice Surgery Consortium for Assessment and Research (NOSCAR) summit.

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

    Science.gov (United States)

    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.

  11. Natural Orifice Transluminal Endoscopic Surgery (NOTES) - současný stav, vlastní zkušenosti

    Czech Academy of Sciences Publication Activity Database

    Ryska, O.; Martínek, J.; Doležel, R.; Filípková, T.; Juhás, Štefan; Juhásová, Jana; Zavoral, M.; Ryska, M.

    2011-01-01

    Roč. 65, č. 5 (2011), s. 264-271 ISSN 1210-7824 R&D Projects: GA MZd NS9994 Institutional research plan: CEZ:AV0Z50450515 Keywords : NOTES * endoscopy * minimal invasive surgery Subject RIV: FJ - Surgery incl. Transplants

  12. Current status and prerequisites for natural orifice translumenal endoscopic surgery (NOTES).

    Science.gov (United States)

    Tomikawa, Morimasa; Xu, Hao; Hashizume, Makoto

    2010-10-01

    Natural orifice translumenal endoscopic surgery (NOTES) is a sophisticated form of endoscopic surgery whose use has recently spread rapidly around the world. Although hundreds of reports of animal studies and clinical cases about NOTES have been published since 2004, NOTES is still in the experimental phase. The formation of an iatrogenic incision in the lumenal wall of intraperitoneal organs is a major disadvantage of NOTES. No reliable technique for complete closure has yet been established, and this problem must be resolved before NOTES can be adopted as a routine clinical practice. Several devices for the closure of lumenal incisions in the stomach or colorectum have been developed, and their safety and usefulness have been examined in animal studies and clinical cases. Kyushu University has been involved in furthering the adoption of NOTES as a routine clinical practice, and the Kyushu University Training Center for Minimally Invasive Surgery holds training sessions on endoscopic surgical techniques for surgeons from all over Japan. Studies to develop a navigation system and robotic technology for use with NOTES are also in progress at Kyushu University. The further development of endoscopy-related technologies and equipment, such as robotic technology, is therefore essential to allow the safe, widespread adoption of pure NOTES.

  13. Improvements in robotic natural orifice surgery with a novel material handling system.

    Science.gov (United States)

    Midday, Jeff; Nelson, Carl A; Oleynikov, Dmitry

    2013-09-01

    Natural orifice translumenal endoscopic surgery (NOTES) has many potential advantages over other minimally invasive surgical techniques, but it presents a number of challenges introduced by the restrictive natural access points. Fully insertable dexterous in vivo robots have been developed that eliminate the spatial restrictions of the entry point, but they also are isolated within the abdomen. A material handling system (MHS) developed to bridge the gap between the in vivo robots and the surgical team promises a number of improvements over other current technologies. The MHS was implemented with two different nonsurvival swine models to validate the utility and benefits of the system. The first procedure was attempted transgastrically but proved too difficult because the geometry of the esophagus was prohibitively small. The system was instead inserted via a 50-mm GelPort and tested for robustness. The second procedure used a transvaginal insertion via a custom 25-mm trocar. Throughout both procedures, the practitioners were asked for qualitative feedback regarding the effectiveness of the device and its long-term efficiencies. The MHS was able to deliver a standard surgical staple securely to the peritoneal cavity. The practitioner was able to use the laparoscopic grasper both to insert and to remove the staple from the MHS. The system also proved capable of maintaining insufflation pressure throughout a procedure. It was cycled a total of five times in both the insertion and the retraction directions. Visualization from the MHS camera was poor at times because the lighting on the system was somewhat inadequate. No excessive bleeding or collateral damage to surrounding tissues was observed during the procedure. This study demonstrated that the MHS is fully capable of achieving payload transport during a NOTES operation. The system is intuitive and easy to use. It dramatically decreases collateral trauma in the natural access point and can advantageously reduce

  14. Natural-orifice transluminal endoscopic surgery (NOTES) in Europe: summary of the working group reports of the Euro-NOTES meeting 2010

    DEFF Research Database (Denmark)

    Meining, A; Feussner, H; Swain, P

    2011-01-01

    collaboration and indications, robotics and platforms, and matters related to training and education. This review summarizes consensus statements of the working groups to give an overview of what has been achieved so far and what might be relevant for research related to NOTES in the near future....... formed, consisting of participants with varying scientific and medical backgrounds. Each group was assigned to an important topic: the correct strategy for dealing with bacterial contamination and related complications, the question of the ideal entry point and secure closure, interdisciplinary...

  15. [Transluminal esophagoplasty (TE)].

    Science.gov (United States)

    Simonetti, G; Meloni, G B; Urigo, F; Canalis, G C; Tomiselli, A; Trignano, M; Bresadola, F

    1985-10-01

    The authors analyze their experience on 9 cases of esophageal stenosis dilated by "Grüntzig" type balloon catheter under fluoroscopic examination (transluminal esophagus plastica: TE). This procedure also allows dilatation of severe narrowing, offering distinct advantages represented by: low risk, easy performance, good tolerance, reduction or disappearance of disphagia. Esophageal perforation is possible, though it never appeared in author's experience.

  16. 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

  17. 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.

  18. Transgastric organ resection solely with the prototype R-scope and the self-approximating transluminal access technique.

    Science.gov (United States)

    Moyer, Matthew T; Haluck, Randy S; Gopal, Jegan; Pauli, Eric M; Mathew, Abraham

    2010-07-01

    The self-approximating transluminal access technique (STAT) has been demonstrated to provide safe transluminal access and in-line endoscope positioning to target abdominal organs during natural orifice transluminal endoscopic surgery (NOTES). To date, organ resection with NOTES has typically required percutaneous assistance. We hypothesized that the in-line positioning and partial stability provided by STAT would allow single-access NOTES procedures if a multiarticulated endoscope could be used. Assessment of single-site NOTES, using STAT and a prototype, multi-articulated endoscope. Animal survival study. Penn State Hershey Medical Center Research Laboratories. Thirteen pigs underwent NOTES using a prototype endoscope with 2 articulated channels, a grasping forceps, and an insulated-tip needle-knife. The gallbladder was dissected using a fundus down technique, and hemoclips and a detachable loop were placed on the cystic duct and artery before removal. After a 2- to 3-week observation period, animals were euthanized and necropsy performed. All target organs were successfully resected without laparoscopic assistance. Significant complications were 2 perforations (1 caused by a prototype duodenal occlusion device and 1 caused by enterotomy during cholecystectomy) and 1 entrapment of the small bowel with an endoloop. Postoperatively, all animals gained weight appropriately with 1 killed on postoperative day 12 because of lethargy (cystic duct leak/biloma). This is a limited animal survival study without control arm. The combination of the R-scope and STAT does allow effective, single-site NOTES procedures; however, although the R-scope provides improved tissue manipulation and visibility, the complications incurred here suggest that further improvements in devices and technique will be required for safe and effective single-site NOTES procedures. Copyright 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  19. 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.

  20. Morphometry of the Myopectineal Orifice

    African Journals Online (AJOL)

    Hp 630 Dual Core

    Morphometry of the Myopectineal Orifice: Relevance in Prosthesis Hernia Repair. B.M. Ndung'u, .C. Koech, M.K. Tharao ... inguinofemoral hernias occur through a weakness in a common potential weak area at the lower end of the abdomen. ..... polypropylene mesh in vivo: an experimental study in dogs. Eur J Surg. 1998 ...

  1. Impacte fisiològic de la cirurgia endoscòpica transluminal a través d’orificis naturals (NOTES) utilitzant diferents vies d’accés: estudi comparatiu en un model porcí

    OpenAIRE

    Guarner Argente, Carlos

    2011-01-01

    [cat] L’aparició de la cirurgia mínimament invasiva ha revolucionat el camp de la cirurgia abdominal. El cirurgians intenten minimitzar el dany produït per les grans incisions de la cirurgia oberta mitjançant la tecnologia endoscòpica. D’altra banda, els endoscopistes tenen la possibilitat de realitzar teràpies cada cop més agressives i que substitueixen, en molts casos, la necessitat de cirurgia El paradigma de la cirurgia combinada amb l’endoscòpia és la cirurgia endoscòpica transluminal a ...

  2. 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.

  3. 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...

  4. Improved Orifice Plate for Spray Gun

    Science.gov (United States)

    Cunningham, W.

    1986-01-01

    Erratic spray pattern of commercial spray gun changed to repeatable one by simple redesign of two parts. In modified spray gun orifice plate and polytetrafluoroethylene bushing redesigned to assure centering and alignment with nozzle. Such improvement useful in many industrial applications requiring repeatable spray patterns. Might include spraying of foam insulation, paint, other protective coatings, detergents, abrasives, adhesives, process chemicals, or fuels. Unmodified spray gun produces erratic spray because lateral misalignment between orifice plate and nozzle.

  5. 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

  6. Double orifice mitral valve: A case report

    Directory of Open Access Journals (Sweden)

    Musić Ljilja

    2016-01-01

    Full Text Available Introduction. Double orifice mitrol valve (DOMV is a very rare congenital heart defect. Case report. We reported 20-year-old male referred to our center due to evaluation of his cardiologic status. He was operated on shortly after birth for a tracheoesophageal fistula. Accidentally, echocardiography examination at the age of 4 years revealed double orifice mitral valve (DOMV without the presence of mitral regurgitation, as well as mitral stenosis, with normal dimensions of all cardiac chambers. The patient was asymptomatic, even more he was a kick boxer. His physical finding was normal. Electrocardiography showed regular sinus rhythm, incomplete right bundle branch block. Transthoracic echocardiography (TTE examination revealed the normal size of the left atrial, mitral leaflets were slightly more redundant. The left and right heart chambers, aorta, tricuspid valve and pulmonary artery valve were normal. During TTE examination on a short axis view two asymmetric mitral orifices were seen as a double mitral orifice through which we registered normal flow, without regurgitation and mitral stenosis. Transesophageal echocardiography (TEE examination from the transgastric view at the level of mitral valve, showed 2 single asymmetric mitral orifices separated by fibrous tissue, mitral leaflet with a separate insertion of hordes for each orifice. Conclusion. The presented patient with DOMV is the only one recognized in our country. The case is interesting because during 16-year a follow-up period there were no functional changes despite the fact that he performed very demanded sport activities. This is very important because there is no information in the literature about that.

  7. Quasisteady aero-acoustic response of orifices

    NARCIS (Netherlands)

    Durrieu, P.; Hofmans, G.; Ajello, G.; Boot, R.; Aurégan, Y.; Hirschberg, A.; Peters, M.C.A.M.

    2001-01-01

    The low frequency response of orifices (slit, circular diaphragm, and perforated plate) in the presence of mean flow is well predicted by a quasisteady theory. A refinement is brought to the theory by considering a Mach number dependent vena contracta coefficient. The measurements of the vena

  8. Percutaneous Transluminal Angioplasty of Peripheral Bypass Stenoses

    International Nuclear Information System (INIS)

    Hoksbergen, Arjan W.J.; Legemate, Dink A.; Reekers, Jim A.; Ubbink, Dirk T.; Jacobs, Michael J.H.M.

    1999-01-01

    Purpose: To assess the success of percutaneous transluminal angioplasty (PTA) in treating peripheral bypass stenoses. Methods: Patients who received a femoropopliteal or femorocrural bypass graft for limb ischemia were included in a duplex surveillance program. If duplex ultrasound revealed a short (<2 cm) severe (peak systolic velocity ratio ≥ 4.5) stenosis, patients were scheduled for arteriography and PTA. Fifty-eight peripheral bypass stenoses in 39 grafts in 37 patients were treated with PTA. The cumulative primary patency of treated stenoses was calculated. Results: During the first year after PTA 31 (53%) treated lesions remained patent, 15 (26%) lesions restenosed at a median interval of 5.0 (range 1-12) months and 4 (7%) bypasses occluded. The cumulative primary patency of 58 treated graft stenoses at 1 year was 60% [95% confidence interval (CI) 46%-74%] and 55% (95% CI 41%-70%) at 2 years. Graft body stenoses showed a better 2-year cumulative primary patency (86%; 95% CI 68%-100%) compared with juxta-anastomotic lesions (45%; 95% CI 29%-62%; p < 0.05). Conclusion: PTA is justifiable as the initial treatment of peripheral bypass stenoses. Nevertheless, the restenosis rate is rather high, especially in juxta-anastomotic lesions. Continuation of duplex surveillance after PTA and timely reintervention is recommended

  9. 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.

  10. 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)

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Double-orifice mitral valve associated with atrioventricular canal ...

    African Journals Online (AJOL)

    A 4 year-old male presented with effort dyspnea, and was diagnosed as atrioventricular canal defects. This finding was confirmed by open heart surgery, and a congenital double orifice mitral valve was discovered. The septal defect was closed but the double orifice mitral valve was respected because of the absence of ...

  16. 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.)

  17. 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.

  18. 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.)

  19. 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.

  20. Flow balancing orifice for ITER toroidal field coil

    Science.gov (United States)

    Litvinovich, A. V.; Y Rodin, I.; Kovalchuk, O. A.; Safonov, A. V.; Stepanov, D. B.; Guryeva, T. M.

    2017-12-01

    Flow balancing orifices (FBOs) are used in in International thermonuclear experimental reactor (ITER) Toroidal Field coil to uniform flow rate of cooling gas in the side double pancakes which have a different conductor length: 99 m and 305 m, respectively. FBOs consist of straight parts, elbows produced from a 316L stainless steel tube 21.34 x 2.11 mm and orifices made from a 316L stainless steel rod. Each of right and left FBOs contains 6 orifices, straight FBOs contain 4 and 6 orifices. Before manufacturing of qualification samples D.V. Efremov Institute of Electrophysical Apparatus (JSC NIIEFA) proposed to ITER a new approach to provide the seamless connection between a tube and a plate therefore the most critical weld between the orifice with 1 mm thickness and the tube removed from the FBOs final design. The proposed orifice diameter is three times less than the minimum requirement of the ISO 5167, therefore it was tasked to define accuracy of calculation flow characteristics at room temperature and compare with the experimental data. In 2015 the qualification samples of flow balancing orifices were produced and tested. The results of experimental data showed that the deviation of calculated data is less than 7%. Based on this result and other tests ITER approved the design of FBOs, which made it possible to start the serial production. In 2016 JSC NIIEFA delivered 50 FBOs to ITER, i.e. 24 left side, 24 right side and 2 straight FBOs. In order to define the quality of FBOs the test facility in JSC NIIEFA was prepared. The helium tightness test at 10-9 m3·Pa/s the pressure up to 3 MPa, flow rate measuring at the various pressure drops, the non-destructive tests of orifices and weld seams (ISO 5817, class B) were conducted. Other tests such as check dimensions and thermo cycling 300 - 80 - 300 K also were carried out for each FBO.

  1. 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.

  2. Meibomian orifices and Marx's line. Studied by triple vital staining.

    Science.gov (United States)

    Norn, M

    1985-12-01

    The ciliary margins of the lower lids have been vital stained by the lipid-specific Sudan III powder, fluorescein 0.1% and the bottom of the lacrimal river (Marx's line) by lissamine green 1% in 100 cases. The Meibomian orifices are situated in a straight row just in front of the Marx's line in the lipid phase. With increasing age (greater than 50 years) the orifices are more often displaced and also discharge their lipid in the depth of the aqueous phase. The number averaged 21.5 in the lipid phase and 1.7 in the aqueous phase. Active orifices staining with lipid were found in 45% of all orifices in normals, independent of age, and were increased in conjunctivitis in the lipid phase. Lissamine green-stained orifices were independent of age, phase and diagnosis. The anterior edge of Marx's line may run an irregular course in elderly normals (greater than 50 years), significantly more often in conjunctivitis and blepharitis.

  3. 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

  4. 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

  5. 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

  6. 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)

  7. Detonation Initiation by Shock Reflection from an Orifice Plate

    Science.gov (United States)

    Ciccarelli, G.; de Witt, B.

    2006-07-01

    Results from an experimental investigation of the interaction of a “non-ideal” shock wave and a single obstacle are reported. The shock wave is produced ahead of an accelerated flame in a 14 cm inner-diameter tube partially filled with orifice plates. The shock wave interacts with a single larger blockage orifice plate placed 15-45 cm after the last orifice plate in the flame acceleration section of the tube. Experiments were performed with stoichiometric ethylene-oxygen mixtures with varying amounts of nitrogen dilution at atmospheric pressure and temperature. The critical nitrogen dilution was found for detonation initiation. It is shown that detonation initiation occurs if the chemical induction time based on the reflected shock state is shorter than the time required for an acoustic wave to traverse the orifice plate upstream surface, from the inner to the outer diameter. The similarity between the present results and those obtained from previous investigators looking at detonation initiation by ideal shock reflection produced in a shock tube indicates that the phenomenon is not sensitive to the detailed structure of the shock front but only on the average shock strength.

  8. On the performance and flow characteristics of jet pumps with multiple orifices

    NARCIS (Netherlands)

    Oosterhuis, Joris; Timmer, Michael Andreas Gerardus; Bühler, Simon; van der Meer, Theodorus H.; Wilcox, Douglas

    2016-01-01

    The design of compact thermoacoustic devices requires compact jet pump geometries, which can be realized by employing jet pumps with multiple orifices. The oscillatory flow through the orifice(s) of a jet pump generates asymmetric hydrodynamic end effects, which result in a time-averaged pressure

  9. 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)

  10. Double Orifice Fissured Subaortic Membrane in the Adult

    Directory of Open Access Journals (Sweden)

    Giordano Zampi

    2017-01-01

    Full Text Available Left ventricle outflow tract obstruction is a relatively common form of congenital heart disease, occurring in 2.8 out of 10,000 live births and accounts for 3-6% of congenital heart diseases. Subvalvular aortic stenosis can be either a fixed stenosis resulting from subaortic membrane or a dynamic stenosis because of hypertrophic cardiomyopathy. We described an original and rare image of double orifice fissured subaortic membrane in the adult.

  11. 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

  12. 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)

  13. 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.

  14. Long-term outcome of percutaneous transluminal septal myocardial ablation in hypertrophic obstructive cardiomyopathy: a Scandinavian multicenter study

    DEFF Research Database (Denmark)

    Jensen, Morten Kvistholm; Almaas, Vibeke Marie; Jacobsson, Linda

    2011-01-01

    Single-center reports on percutaneous transluminal septal myocardial ablation (PTSMA) in patients with hypertrophic obstructive cardiomyopathy have shown considerable differences in outcome.......Single-center reports on percutaneous transluminal septal myocardial ablation (PTSMA) in patients with hypertrophic obstructive cardiomyopathy have shown considerable differences in outcome....

  15. Parameters for dimensional inspection of orifice plates and roughness of the straight stretches of the tubing

    Directory of Open Access Journals (Sweden)

    Alberto Kennedy de Almeida Medeiros

    2006-01-01

    Full Text Available According to the Technical Regulation of Measurement of Petroleum and Natural Gas (approved in 2000 by ANP - the Petroleum National Agency of Brazil, the systems of measurement of natural gas should use ultra-sonic flow meters, turbines and, especially, the orifice plates, which represent the most expressive base of the flow systems, being used in the fiscal and operational measurements. This work aims to evaluate the parameters that should be accounted for during the dimensional inspection of orifice plate and roughness of the straight stretches of the tubing used for measurement of natural gas, with the objective of guiding the responsible professionals for the measurement of volumes of natural gas by orifice plate, as well as the professionals of calibration laboratories. In this work, minimum specifications are recommended, irrespective of the pressure tapping or orifice type, in agreement with the norms ISO, AGA and the ANP regulations. The influence of these specifications on the parameters used in the calculation of the volumetric flow is also analyzed.Segundo o Regulamento Técnico de Medição de Petróleo e Gás natural (aprovado em 2000, nos sistemas de medições de gás natural devem ser utilizados medidores de vazão tipo ultra-sônico, turbinas e, em especial, as placas de orifício, que representam a base mais expressiva do sistema de vazão, sendo empregadas nas medições fiscais e nas medições operacionais. Este trabalho tem como objetivo avaliar os parâmetros a serem considerados durante a inspeção dimensional de placa de orifício e da rugosidade dos trechos retos de tubulações usados para medição de gás natural, visando orientar os profissionais responsáveis pela medição de volume de gás natural por placa de orifício, como também a profissionais de laboratórios de calibração visando a emissão do certificado de calibração. No trabalho, são recomendadas especificações mínimas, indepen-dentemente do

  16. Kilowatt Isotope Power System: component test report for the ground demonstration system jet condenser orifice performance. 77-KIPS-103

    Energy Technology Data Exchange (ETDEWEB)

    Brainard, E.L.

    1977-11-08

    The purpose of these tests was to determine which orifice elements achieved satisfactory hydraulic and thermal performance prior to their incorporation into the Jet Condenser Assembly. Requirements were as set forth within the Kilowatt Isotope Power System (KIPS) Component Test Procedure number 414 for the Jet Condenser Orifice Performance testing. The results of the performance testing conducted on the Jet Condenser Orifices are presented. Part Number 720841 Jet Condenser Orifice Nozzle successfully completed the orifice screening tests.

  17. Acoustic Luneburg lens using orifice-type metamaterial unit cells

    Science.gov (United States)

    Park, Choon Mahn; Lee, Sang Hun

    2018-02-01

    A two-dimensional acoustic Luneburg lens that can be easily expanded into a three-dimensional sphere is fabricated. The required spatial distribution of the refractive index for this Luneburg lens is realized using the characteristics of orifice-type metamaterial unit cells. Typical characteristics of the resulting acoustic Luneburg lens, such as its aberration-free performance and capability for antipodal focusing of the lens for the incident plane waves, are investigated through experiments and simulations with the attenuation loss at frequencies that satisfy the homogeneous medium condition of the metamaterial. With the designed metamaterial, we achieved the minimum spot that lies within the classical diffraction limit at the focal point.

  18. 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

  19. 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

  20. 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

  1. 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)

  2. Optimization of orifice geometry for crossflow mixing in a cylindrical duct

    OpenAIRE

    Kroll, JT; Sowa, WA; Samuelsen, GS; Holdeman, JD

    2000-01-01

    Mixing of gaseous jets in a crossflow has significant applications in combustion science and engineering, one example of which is the mixing zone of a rich-burn/quick-mix/lean-burn gas turbine combustor. A major design question is the jet orifice shape and jet orifice number that optimizes the mixing performance. To delineate the optimal orifice features for a given axial distance and momentum-flux ratio, a statistical design of experiments test matrix was established around three variables: ...

  3. 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.

  4. Systematic review of exercise training or percutaneous transluminal angioplasty for intermittent claudication

    NARCIS (Netherlands)

    Frans, F. A.; Bipat, S.; Reekers, J. A.; Legemate, D. A.; Koelemay, M. J. W.

    2012-01-01

    Background: The aim was to summarize the results of all randomized clinical trials (RCTs) comparing percutaneous transluminal angioplasty (PTA) with (supervised) exercise therapy ((S)ET) in patients with intermittent claudication (IC) to obtain the best estimates of their relative effectiveness.

  5. Theoretical and numerical study of hydraulic characteristics of orifice energy dissipator

    Directory of Open Access Journals (Sweden)

    Ning He

    2010-06-01

    Full Text Available Different factors affecting the efficiency of the orifice energy dissipator were investigated based on a series of theoretical analyses and numerical simulations. The main factors investigated by dimension analysis were identified, including the Reynolds number (Re, the ratio of the orifice diameter to the inner diameter of the pipe (d/D, and the ratio of distances between orifices to the inner diameter of the pipe (L/D. Then, numerical simulations were conducted with a k-ɛ two-equation turbulence model. The calculation results show the following: Hydraulic characteristics change dramatically as flow passes through the orifice, with abruptly increasing velocity and turbulent energy, and decreasing pressure. The turbulent energy appears to be low in the middle and high near the pipe wall. For the energy dissipation setup with only one orifice, when Re is smaller than 105, the orifice energy dissipation coefficient K increases rapidly with the increase of Re. When Re is larger than 105, K gradually stabilizes. As d/D increases, K and the length of the recirculation region L1 show similar variation patterns, which inversely vary with d/D. The function curves can be approximated as straight lines. For the energy dissipation model with two orifices, because of different incoming flows at different orifices, the energy dissipation coefficient of the second orifice (K2 is smaller than that of the first. If L/D is less than 5, the K value of the L/D model, depending on the variation of K2, increases with the spacing between two orifices L, and an orifice cannot fulfill its energy dissipation function. If L/D is greater than 5, K2 tends to be steady; thus, the K value of the L/D model gradually stabilizes. Then, the flow fully develops, and L has almost no impact on the value of K.

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

    National Research Council Canada - National Science Library

    Nurick, W. H; Ohanian, T; Talley, D. G; Strakey, P. A

    2007-01-01

    .... This paper deals with predicting the initiation of cavitation, cavitation impacts on Cc, and non-cavitation impacts on Cd from L/D of 5 sharp-edge orifices with both single angle and compound angle directional flow...

  7. Swirling flow in a tube with variably-shaped outlet orifices: An LES and VLES study

    International Nuclear Information System (INIS)

    Chang, C.-Y.; Jakirlić, S.; Dietrich, K.; Basara, B.; Tropea, C.

    2014-01-01

    Highlights: • A new VLES model is formulated and interactively validated in some generic flows. • VLES is applied to a swirling pipe characterized by differently-shaped outlet orifice. • Complementary LES and RANS computations are also performed. • Enhancement of the ‘core jet’ is reproduced by VLES and LES, not by RANS. • Opposite orientation of the mean streamlines and the helical structures is captured. - Abstract: The swirling flow in a tube with the outlet designed in the form of an orifice nozzle with centered and eccentrical openings, investigated experimentally by Grundmann et al. (2012), was studied computationally by employing Large Eddy Simulation (LES) method and a Hybrid LES/RANS (Reynolds-Averaged Navier–Stokes) method. The latter method, denoted by VLES (Very Large Eddy Simulation) according to Speziale (1998), represents a variable resolution computational scheme enabling a seamless transition from RANS to the direct numerical solution of the Navier–Stokes equations (DNS) depending on the ratio of the turbulent viscosities associated with the unresolved scales corresponding to the LES cut-off and the ‘unsteady’ scales pertinent to the turbulent properties of the VLES residual motion, which varies within the flow domain. Before computing the swirling pipe configuration, the VLES model is interactively validated in the process of the model derivation in some generic flows featured by natural decay of the homogeneous isotropic turbulence and separation from a curved continuous surface. The background RANS model representing the basis of the VLES method is the eddy-viscosity-based ζ-f model proposed by Hanjalic et al. (2004). The inflowing swirl generated by two tangential inlets has the same intensity in all cases considered. However, the abrupt outlet cross-section contraction created by variably-shaped orifices causes strong modification of the flow within the tube resembling a three-layered structure characterized by an

  8. 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)

  9. The influence of orifice height on flow rate of powder excipients.

    Science.gov (United States)

    Zatloukal, Z; Sklubalová, Z

    2011-12-01

    The influence of the orifice height of a cylindrical, flat-bottomed hopper on the mass flow rate of the free-flowable size fractions of sodium chloride and boric acid was investigated. It was observed that a zone of sudden acceleration of the mass flow under gravity occurred when a critical orifice height had been achieved. Based on the results, an orifice diameter equal to 12 mm with a height of between 8-16 mm is recommended for the faster flow of sodium chloride while an orifice diameter equal to 8 mm with a height of less than 8mm is appropriate for the slower flow of boric acid. In summary, the orifice height should be taken into consideration as an important parameter of a cylindrical test hopper in order to obtain a reproducible and comparable mass flow as the single-point characteristic of powder flowability.

  10. Gas Generator Feedline Orifice Sizing Methodology: Effects of Unsteadiness and Non-Axisymmetric Flow

    Science.gov (United States)

    Rothermel, Jeffry; West, Jeffrey S.

    2011-01-01

    Engine LH2 and LO2 gas generator feed assemblies were modeled with computational fluid dynamics (CFD) methods at 100% rated power level, using on-center square- and round-edge orifices. The purpose of the orifices is to regulate the flow of fuel and oxidizer to the gas generator, enabling optimal power supply to the turbine and pump assemblies. The unsteady Reynolds-Averaged Navier-Stokes equations were solved on unstructured grids at second-order spatial and temporal accuracy. The LO2 model was validated against published experimental data and semi-empirical relationships for thin-plate orifices over a range of Reynolds numbers. Predictions for the LO2 square- and round-edge orifices precisely match experiment and semi-empirical formulas, despite complex feedline geometry whereby a portion of the flow from the engine main feedlines travels at a right-angle through a smaller-diameter pipe containing the orifice. Predictions for LH2 square- and round-edge orifice designs match experiment and semi-empirical formulas to varying degrees depending on the semi-empirical formula being evaluated. LO2 mass flow rate through the square-edge orifice is predicted to be 25 percent less than the flow rate budgeted in the original engine balance, which was subsequently modified. LH2 mass flow rate through the square-edge orifice is predicted to be 5 percent greater than the flow rate budgeted in the engine balance. Since CFD predictions for LO2 and LH2 square-edge orifice pressure loss coefficients, K, both agree with published data, the equation for K has been used to define a procedure for orifice sizing.

  11. 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)

  12. 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.

  13. 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)

  14. 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.

  15. 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

  16. Novel Design of Orifice Type Control Element for Mitigating Instabilities Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An orifice element is commonly used in liquid rocket engine test facilities to provide a large reduction in pressure over a very small distance in the piping system....

  17. Novel Design of Orifice Type Control Element for Mitigating Instabilities Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An orifice element is commonly used in liquid rocket engine test facilities either as a flow metering device, or to provide a large reduction in pressure over a very...

  18. Diagnostic evaluation of appendiceal orifice inflammation in ulcerative colitis.

    Science.gov (United States)

    Zhan, Da Qin; Chen, Xing; Wang, Rong; Zhang, Jing; Zhao, Dan Yu; Zhang, Shu Jing; Wang, Zhi Feng; Ma, Rui Jun; Hou, Bo

    2016-09-01

    To evaluate the diagnostic significance of appendiceal orifice inflammation (AOI) in ulcerative colitis (UC) patients. We retrospectively examined data from patients with colitis from May 2010 to January 2014 and assigned them to two groups: UC cases and specific colitis cases. First, we clarified the difference in the AOI+ rate between the two groups. Thereafter, imaging findings of all the patients with colitis were re-examined. Features of AOI alone or in combination with proctitis (referred to as "combination features") were considered as the two separate diagnostic criteria for diagnosing UC. By comparing the current diagnoses with the previous diagnoses, evaluation indexes were obtained. A total of 3582 colitis cases (UC cases: 427; specific colitis cases: 3155) were examined. The mean AOI+ rates in UC and specific colitis cases were 26.2% and 0.7%, respectively; a Chi-squared test indicated that the difference between these rates was statistically significant (x2=6.81; pUC, the sensitivity was 26.2% [95% confidence interval (CI), 22.3%-30.6%], agreement rate was 90.6%, and specificity was 99.3% (95% CI, 98.9%-99.5%). When the combination features were used to diagnose UC, the sensitivity was 26.2% (95% CI, 22.3%-30.6%), agreement rate was 91.1%, and specificity was 99.9% (95% CI, 99.7%-100%). Combining AOI features and proctitis may lead to a more effective UC diagnosis and enable physicians to identify this condition more promptly among miscellaneous diseases.

  19. Investigation of the sound generation mechanisms for in-duct orifice plates.

    Science.gov (United States)

    Tao, Fuyang; Joseph, Phillip; Zhang, Xin; Stalnov, Oksana; Siercke, Matthias; Scheel, Henning

    2017-08-01

    Sound generation due to an orifice plate in a hard-walled flow duct which is commonly used in air distribution systems (ADS) and flow meters is investigated. The aim is to provide an understanding of this noise generation mechanism based on measurements of the source pressure distribution over the orifice plate. A simple model based on Curle's acoustic analogy is described that relates the broadband in-duct sound field to the surface pressure cross spectrum on both sides of the orifice plate. This work describes careful measurements of the surface pressure cross spectrum over the orifice plate from which the surface pressure distribution and correlation length is deduced. This information is then used to predict the radiated in-duct sound field. Agreement within 3 dB between the predicted and directly measured sound fields is obtained, providing direct confirmation that the surface pressure fluctuations acting over the orifice plates are the main noise sources. Based on the developed model, the contributions to the sound field from different radial locations of the orifice plate are calculated. The surface pressure is shown to follow a U 3.9 velocity scaling law and the area over which the surface sources are correlated follows a U 1.8 velocity scaling law.

  20. Effect of Orifice Diameter on Bubble Generation Process in Melt Gas Injection to Prepare Aluminum Foams

    Science.gov (United States)

    Yuan, Jianyu; Li, Yanxiang; Wang, Ningzhen; Cheng, Ying; Chen, Xiang

    2016-06-01

    The bubble generation process in conditioned A356 alloy melt through submerged spiry orifices with a wide diameter range (from 0.07 to 1.0 mm) is investigated in order to prepare aluminum foams with fine pores. The gas flow rate and chamber pressure relationship for each orifice is first determined when blowing gas in atmospheric environment. The effects of chamber pressure ( P c) and orifice diameter ( D o) on bubble size are then analyzed separately when blowing gas in melt. A three-dimensional fitting curve is obtained illustrating both the influences of orifice diameter and chamber pressure on bubble size based on the experimental data. It is found that the bubble size has a V-shaped relationship with orifice diameter and chamber pressure neighboring the optimized parameter ( D o = 0.25 mm, P c = 0.4 MPa). The bubble generation mechanism is proposed based on the Rayleigh-Plesset equation. It is found that the bubbles will not be generated until a threshold pressure difference is reached. The threshold pressure difference is dependent on the orifice diameter, which determines the time span of pre-formation stage and bubble growth stage.

  1. 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.

  2. PIV and DNS analyses of viscoelastic turbulent flows behind a rectangular orifice

    International Nuclear Information System (INIS)

    Tsukahara, Takahiro; Motozawa, Masaaki; Tsurumi, Daisei; Kawaguchi, Yasuo

    2013-01-01

    Highlights: • Viscoelastic fluid turbulence in relaxing and non-equilibrium flow is investigated. • Numerical and experimental results of viscoelastic turbulent orifice flow are provided. • DNS result using Giesekus model agrees well with the experimental one by surfactant solution. • Formation of Kelvin–Helmholtz vortices behind the orifice weakens in viscoelastic flows. • Highly viscoelastic flow reduces the form drag, but increases the skin friction due to extra stress. -- Abstract: We performed PIV (particle image velocimetry) measurements and DNS (direct numerical simulations) on turbulent orifice flows for the Newtonian fluid and viscoelastic fluids, and compared their results with emphasis on turbulence statistics and vortical motions just behind the orifice rib. In the experiment, a cationic surfactant solution of CTAC (cetyltrimethyl ammonium chloride) was chosen as the viscoelastic fluid that is known to provide substantial drag reduction in the case of smooth-wall turbulence. In the viscoelastic flows, the formation of the Kelvin–Helmholtz vortices emanating from the orifice edge was found to be attenuated compared to the Newtonian case, resulting in the suppression of turbulent eddies and Reynolds shear stress behind the orifice. However, the variation of the drag depended on the Reynolds number and the surfactant concentration (or the Weissenberg number): that is, the drag-reducing effect can be achieved only in limited conditions or low Reynolds-number flows. Although DNS results was found to be in qualitative agreement with the experimental data, we discussed also inconsistency between the experimental and DNS results

  3. Enrichment of syngas-converting communities from a multi-orifice baffled bioreactor.

    Science.gov (United States)

    Arantes, Ana L; Alves, Joana I; Stams, Alfons J M; Alves, M Madalena; Sousa, Diana Z

    2017-11-21

    The substitution of natural gas by renewable biomethane is an interesting option to reduce global carbon footprint. Syngas fermentation has potential in this context, as a diverse range of low-biodegradable materials that can be used. In this study, anaerobic sludge acclimatized to syngas in a multi-orifice baffled bioreactor (MOBB) was used to start enrichments with CO. The main goals were to identify the key players in CO conversion and evaluate potential interspecies metabolic interactions conferring robustness to the process. Anaerobic sludge incubated with 0.7 × 10 5  Pa CO produced methane and acetate. When the antibiotics vancomycin and/or erythromycin were added, no methane was produced, indicating that direct methanogenesis from CO did not occur. Acetobacterium and Sporomusa were the predominant bacterial species in CO-converting enrichments, together with methanogens from the genera Methanobacterium and Methanospirillum. Subsequently, a highly enriched culture mainly composed of a Sporomusa sp. was obtained that could convert up to 1.7 × 10 5  Pa CO to hydrogen and acetate. These results attest the role of Sporomusa species in the enrichment as primary CO utilizers and show their importance for methane production as conveyers of hydrogen to methanogens present in the culture. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  4. 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

  5. Subclavian steal syndrome: treatment by percutaneous transluminal angioplasty; Sindrome do roubo da subclavia: tratamento por angioplastia transluminar percutanea

    Energy Technology Data Exchange (ETDEWEB)

    Abath, Carlos Gustavo Coutinho [Instituto de Medicina e Cirurgia, Recife, PE (Brazil)]|[Hospital Memorial Sao Jose, Recife, PE (Brazil); Silva, Marcos Antonio Barbosa da [Instituto de Medicina e Cirurgia, Recife, PE (Brazil); Brito, Norma Maria Tenorio [Hospital Memorial Sao Jose, Recife, PE (Brazil); Marques, Silvio Romero; Santa Cruz, Rodolfo [Pernambuco Univ., Recife, PE (Brazil). Hospital das Clinicas; Henrique, Darcy [Real Hospital Portugues, Recife, PE (Brazil)

    1995-09-01

    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.

  6. 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.

  7. Normal and stenotic human aortic valve opening: in vitro assessment of orifice area changes with flow.

    Science.gov (United States)

    Montarello, J K; Perakis, A C; Rosenthal, E; Boyd, E G; Yates, A K; Deverall, P B; Sowton, E; Curry, P V

    1990-06-01

    The ability to measure aortic valve area clinically has emphasized the need to understand the changes in aortic valve orifice area during flow. To compare the performance of normal and stenotic human aortic valves we used a pulsatile flow model that simulated in vivo flow conditions. Five normal autopsy specimens and 15 stenotic valves removed at operation were mounted into the model. Valve function was assessed by analysis of video recordings of valve leaflet motion during flow. Over the flow rates tested normal valves demonstrated a linear increase in orifice area. There was no resistance to leaflet opening and valve closure was rapid. The majority of stenotic valves demonstrated an increase in orifice area at low flow rates. No valve showed any increase in maximal area beyond flow rates of 3 l min-1. Increased leaflet resistance of these abnormal valves resulted in notably slower opening and closing rates. In patients with a high cardiac output and severe stenosis, overestimation of the anatomic orifice area derived by the Gorlin equation can result. This is not related to variability in maximal orifice area.

  8. 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

  9. 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

  10. 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)

  11. Color Doppler imaging of the ophthalmic artery blood flow spectra of patients who have had a transient ischemic attack. Correlations with generalized iris transluminance and pseudoexfoliation syndrome.

    Science.gov (United States)

    Repo, L P; Suhonen, M T; Teräsvirta, M E; Koivisto, K J

    1995-08-01

    To study the interrelations among pseudoexfoliation syndrome (PXS), abnormal iris transluminance, and ophthalmic artery blood flow in a controlled study. Ultrasonographic examination using color Doppler imaging (CDI) was performed on the ophthalmic arteries of 46 unselected patients (92 eyes) who have had at least one transient ischemic attack (TIA) and on 32 healthy subjects (64 eyes). The authors recorded the peak systolic and end diastolic velocities and determined the resistivity indices. Iris transillumination photographs were evaluated by two ophthalmologists in a blind trial to show the presence of abnormal iris transluminance of these eyes. Biomicroscopic examination was performed to show the presence of PXS. The frequency of abnormal iris transluminance in the whole group of patients who had had a TIA and in control subjects was 63% and 28%, respectively (P iris transluminance and healthy subjects without transluminance was statistically significant (P iris transluminance. The exceptionally high frequency of PXS in the eyes of patients who had had a TIA with positive iris transluminance suggests pathologic changes in the blood supply of PXS eyes. High values of resistivity indices for the ophthalmic arteries of these eyes suggest that disturbances in the ciliary circulation may be the possible cause of these changes.

  12. High-level vibration and noise analysis of nuclear pipes with orifice

    International Nuclear Information System (INIS)

    Mao, Qing; Bi, Qincheng; Li, Huixiong; Duan, Quan; Zhang, Yixiong; Zang, Fenggang; Xiang, Wenyuan

    2003-01-01

    Vibration caused structure failure is a common occurrence in industry piping. In the design process of nuclear piping, fluid-induced vibration effect is normally not taken into account because of the lack of practical guidance and regulatory requirements. Nuclear pipes suffering from high-level vibration and noise problems have been studied in this paper. Field investigation and vibration measurement provide basic information to exclude resonance and pump excitation from the fundamental cause of this issue. Since the vibration and noise is extremely high at the position near a single throttle orifice, cavitation after the orifice is believed to be the fundamental reason to cause the problem. Numerical analysis and laboratory simulating test have been implemented to validate this engineering judgment. In order to eliminate cavitation phenomenon, multi-step orifice design as well as the relevant validation test have been made. After field modification, the vibration and noise are both significantly reduced. (author)

  13. Case Study of Variable Orifice Damper for Seismic Protection of Structures

    Directory of Open Access Journals (Sweden)

    Cristian Pastia

    2009-01-01

    Full Text Available The seismic protection is, without any doubt, a worldwide priority, and that is why one of the main preoccupations of the researchers in the field is finding some innovative concepts concerning the seismic protection of the structures. The aim of the paper consists in the analytical and numerical study of the variable orifice damper implemented in a single degree of freedom (SDOF structure in order to increase people’s safety and reduce the seismic risk. The variable orifice damper is the common semi-active hydraulic device which may be utilized as part of seismic isolation system or within the lateral bracing of a structure. The semi-active control strategy is realized using on-off clipping control algorithm. It is concluded that the variable orifice damper afforded a substantial reduction of the displacement response of a SDOF system in comparison to the response with passive control fluid device.

  14. Bubble Formation at a Submerged Orifice for Aluminum Foams Produced by Gas Injection Method

    Science.gov (United States)

    Fan, Xueliu; Chen, Xiang; Liu, Xingnan; Zhang, Huiming; Li, Yanxiang

    2013-02-01

    The bubble formation at a submerged orifice in the process of aluminum foams produced by gas injection method is investigated. The experimental results show that the increase of the gas flow rate and the orifice diameter can lead to increasing of the bubble size. The large orifice can make the frequency of bubble formation decrease by slowing down the increase of the gas chamber pressure when the gas flow rate increases. The effect of the gas chamber volume on the bubble size can be ignored in the experiment when it expands from 1 to 125 cm3. A theoretical model of bubble formation, expansion, and detachment under constant flow conditions is established to predict the bubble size. The theoretical predictions for air-aluminum melt systems are consistent with the experimental results.

  15. 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...

  16. 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.)

  17. Successful treatment of double-orifice mitral stenosis with percutaneous balloon mitral commissurotomy.

    Science.gov (United States)

    Patted, Suresh V; Halkati, Prabhu C; Ambar, Sameer S; Sattur, Ameet G

    2012-01-01

    Double-orifice mitral valve (DOMV) is an uncommon congenital anomaly, being present in 0.05% of the general population. The isolated occurrence of this anomaly is very rare and, to our knowledge, no data are currently available on the incidence of an isolated DOMV. A DOMV is characterized by a mitral valve with a single fibrous annulus with 2 orifices opening into the left ventricle (LV). Subvalvular structures, especially the tensor apparatus, invariably show various degrees of abnormality. It can substantially obstruct mitral valve inflow or cause mitral valve incompetence. We present a rare case of nineteen-year-old male who underwent percutaneous mitral balloon commissurotomy in stenotic DOMV.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. Radiation-induced skin injury after percutaneous transluminal coronary angioplasty. Case report

    Energy Technology Data Exchange (ETDEWEB)

    Soevik, E. [Dept. of Radiology, National Hospital, Univ. Oslo (Norway); Kloew, N.E. [Dept. of Radiology, National Hospital, Univ. Oslo (Norway); Hellesnes, J. [Dept. of Health Physics, National Hospital, Univ. Oslo (Norway); Lykke, J. [Dept. of Surgery, Stensby Hospital, Minnesund (Norway)

    1995-05-01

    A 58-year-old man underwent percutaneous transluminal coronary angioplasties in June 1992 and May 1993. Approximately 3 weeks after the last procedure, a cutaneous lesion developed into an ulcer over the right scapular region. The ulcer failed to heal with conservative treatment; therefore, surgical excision was performed. The localization and the course of the development indicated injury caused by radiation, and this was confirmed by the histologic examination. To avoid such injury in interventional procedures with long fluoroscopic time, several percautions should be taken. These include continuous surveillance of the X-ray dosage, the use of different projections to avoid exposure to one skin area throughout the whole procedure, keeping the irradiated area as small as possible, and good planning of the procedure. (orig.).

  3. 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%

  4. Apertures with Laval Nozzle and Circular Orifice in Secondary Electron Detector for Environmental Scanning Electron Microscope

    Czech Academy of Sciences Publication Activity Database

    Vyroubal, P.; Maxa, J.; Neděla, Vilém; Jirák, Josef; Hladká, K.

    2013-01-01

    Roč. 8, č. 1 (2013), s. 59-69 ISSN 1802-2308 R&D Projects: GA ČR GAP102/10/1410 Institutional support: RVO:68081731 Keywords : Aperture * Laval nozzle * circular orifice * pressure * detector * Mach number * flow * trajectory of secondary electrons Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  5. 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%.

  6. DNS of viscoelastic turbulent channel flow with rectangular orifice at low Reynolds number

    International Nuclear Information System (INIS)

    Tsukahara, Takahiro; Kawase, Tomohiro; Kawaguchi, Yasuo

    2011-01-01

    Direct numerical simulations of turbulent viscoelastic-fluid flow in a channel with a rectangular orifice were performed to investigate the influence of viscoelasticity on turbulence statistics and turbulent structures downstream of the orifice. The geometry considered is periodic rectangular orifices with 1:2 expansion. The constitutive equation follows the Giesekus model, valid for polymer (or surfactant) solutions, which are generally capable of reducing the turbulent frictional drag in a smooth channel. The friction Reynolds number and the Weissenberg number were set to 100 and 20-30, respectively. A drag reduction of about 20% was achieved in the viscoelastic flows. The onset Reynolds number for the transition from a symmetric to an asymmetric state was found to be shifted to higher values than that for the Newtonian flow. In the viscoelastic flow, the turbulent kinetic energy was decreased and fewer turbulent eddies were observed, as the Kelvin-Helmholtz vortices were quickly damped. Away from the orifice, quasi-streamwise vortices in the viscoelastic flow were sustained for a longer period, accompanied by energy exchange from elastic energy of the viscoelastic fluid to kinetic energy.

  7. 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

  8. 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

  9. 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.

  10. 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)

  11. 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)

  12. On the propagation mechanism of a detonation wave in a round tube with orifice plates

    Science.gov (United States)

    Ciccarelli, G.; Cross, M.

    2016-09-01

    This study deals with the investigation of the detonation propagation mechanism in a circular tube with orifice plates. Experiments were performed with hydrogen air in a 10-cm-inner-diameter tube with the second half of the tube filled with equally spaced orifice plates. A self-sustained Chapman-Jouguet (CJ) detonation wave was initiated in the smooth first half of the tube and transmitted into the orifice-plate-laden second half of the tube. The details of the propagation were obtained using the soot-foil technique. Two types of foils were used between obstacles, a wall-foil placed on the tube wall, and a flat-foil (sooted on both sides) placed horizontally across the diameter of the tube. When placed after the first orifice plate, the flat foil shows symmetric detonation wave diffraction and failure, while the wall foil shows re-initiation via multiple local hot spots created when the decoupled shock wave interacts with the tube wall. At the end of the tube, where the detonation propagated at an average velocity much lower than the theoretical CJ value, the detonation propagation is much more asymmetric with only a few hot spots on the tube wall leading to local detonation initiation. Consecutive foils also show that the detonation structure changes after each obstacle interaction. For a mixture near the detonation propagation limit, detonation re-initiation occurs at a single wall hot spot producing a patch of small detonation cells. The local overdriven detonation wave is short lived, but is sufficient to keep the global explosion front propagating. Results associated with the effect of orifice plate blockage and spacing on the detonation propagation mechanism are also presented.

  13. Neoglottis reconstruction with sternohyoid muscles on upper-tracheal orifice after laryngectomy.

    Science.gov (United States)

    Li, Chang Jiang; Cheng, Lei; Wu, Haitao; Tao, Lei; Zhou, Liang

    2017-01-01

    Ideal speech restoration remains a difficult challenge for patients undergoing laryngectomy so far. Our aim was to explore the feasibility of neoglottic reconstruction with sternohyoid muscles on upper-tracheal orifice after total laryngectomy which can obtain relatively ideal voice rehabilitation. Fifteen male patients are laryngectomized, of whom eight with standard total laryngectomy and seven underwent nonstandard total laryngectomy with epiglottis conserved. After laryngectomy, the upper margin of the anterior hypopharyngeal mucosa (postcricoid mucosa) was stitched to the posterior margin of upper-tracheal orifice and a triangle-shaped neoglottis on upper-tracheal orifice was reconstructed using bilateral sternohyoid muscles near the hyoid bone which were sutured to the posterior wall and bilateral of upper-tracheal orifice. Then tracheolingual root anastomosis was done and reconstruction surgery was completed. Finally, a satisfactory voice was achieved in 14 of 15 patients except one whose neoglottis is stenosed and 11 cases had no severe complications including aspiration erroneous deglutition. The stomach catheters were removed successfully from 4 to 6 weeks after surgery in 11 cases, respectively. The neoglottis had to be closed in three patients because of aspiration problem. One neoglottis was closed 3 weeks after surgical reconstruction because of tracheal rings tear which created a bigger neoglottis. One neoglottis was removed 32 moths after total laryngectomy due to big neoglottis. Another one was closed 3 weeks after surgery by reason of the fear of aspiration without psychological preparation. Therefore, it is feasible to use the sternohyoid muscles for creation of a neoglottis on upper-tracheal orifice and provide an alternative surgical method of the voice restoration for the patients after laryngectomy.

  14. How the anal gland orifice could be found in anal abscess operations

    Directory of Open Access Journals (Sweden)

    Shahram Paydar

    2015-01-01

    Full Text Available Background: On an average 30-50% of patients who undergo incision and drainage (I and D of anal abscess will develop recurrence or fistula formation. It is claimed that finding the internal orifice of anal abscess to distract the corresponding anal gland duct; will decline the rate of future anal fistula. Surgeons supporting I and D alone claim that finding the internal opening is hazardous. This study is conducted to assess short-term results of optional method to manage patients with anal abscess and fitula-in-ano at the same time. Materials and Methods: In this cross-sectional descriptive study 49 from 77 patients with anal abscess whose internal orifice was not identified by pressing on the abscess, diluted hydrogen peroxide (2% and methylene blue was injected into the abscess cavity and the anal canal was inspected to find out the internal opening. Once the opening was distinguished, an incision was given from the anal verge to the internal opening. Results: The internal orifice was identified in 44 out of 49 patients (90% who underwent this new technique. Up to 18 months during follow-up, only 2.5% of patients with primary fistulotomy developed fistula on the site of a previous abscess. Conclusion: Conventional method to seek the internal orifice of anal abscesses is successful in about one-third of cases. By applying this new technique, surgeons would properly find the internal opening in >90% of patients. Needless to say, safe identification of the anal gland orifice in anal abscess disease best helps surgeons to do primary fistulotomy and in turn it would significantly decrease the rate of recurrence in anal abscess and fistula formation.

  15. Investigation of orifice aeroacoustics by means of multi-port methods

    Science.gov (United States)

    Sack, Stefan; Åbom, Mats

    2017-10-01

    Comprehensive methods to cascade active multi-ports, e.g., for acoustic network prediction, have until now only been available for plane waves. This paper presents procedures to combine multi-ports with an arbitrary number of considered duct modes. A multi-port method is used to extract complex mode amplitudes from experimental data of single and tandem in-duct orifice plates for Helmholtz numbers up to around 4 and, hence, beyond the cut-on of several higher order modes. The theory of connecting single multi-ports to linear cascades is derived for the passive properties (the scattering of the system) and the active properties (the source cross-spectrum matrix of the system). One scope of this paper is to investigate the influence of the hydrodynamic near field on the accuracy of both the passive and the active predictions in multi-port cascades. The scattering and the source cross-spectrum matrix of tandem orifice configurations is measured for three cases, namely, with a distance between the plates of 10 duct diameter, for which the downstream orifice is outside the jet of the upstream orifice, 4 duct diameter, and 2 duct diameter (both inside the jet). The results are compared with predictions from single orifice measurements. It is shown that the scattering is only sensitive to disturbed inflow in certain frequency ranges where coupling between the flow and sound field exists, whereas the source cross-spectrum matrix is very sensitive to disturbed inflow for all frequencies. An important part of the analysis is based on an eigenvalue analysis of the scattering matrix and the source cross-spectrum matrix to evaluate the potential of sound amplification and dominant source mechanisms.

  16. Effect of vortex orifice air distributor on granule growth in conical fluidized bed granulation with bottom entry spray

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, Y.; Sekiguchi, I. [Chuo Univ., Tokyo (Japan). Faculty of Science and Engineering

    2000-02-01

    This investigation is undertaken to obtain information on the effect of vortex orifice air distributors on the granule growth in conical fluidized bed granulation with a bottom entry spray. The five types of vortex orifice distributors suitable for a strong swirling air supply at the base of the conical bed were prepared. Although all these orifices consisted of four tangential injection nozzles with the same opening, the opening size of the air injection nozzle in each of the orifices was different. Intensity of the air injection nozzle torque within the vortex orifice was measured by a torque balance method. The granule formation of fluidising lactose particles in the process of size-enlargement was carried out by spraying an aqueous HPC solution into the bed where the moisture content of granules was maintained at or below 0.30 wt %. As a result, granule growth in the bed could be precisely controlled by changes in the air injection nozzle torques arising from the vortex orifice distributor. The extent of granule growth, namely the granule growth conversion increasing with accumulated content of HPC in the bed particles during the operating time decreased according to the air injection nozzle torque within the vortex orifice. Using these process variables, granule growth conversion could be arranged experimentally. It is finally found that one of the features of the proposed air distributor is useful for size-control of granule products in the conical fluidized bed granulation with a bottom entry spray. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Wael H., E-mail: ahmedw@kfupm.edu.sa [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals (KFUPM), P.O. Box 874, Dhahran 31261 (Saudi Arabia); Bello, Mufatiu M.; El Nakla, Meamer; Al Sarkhi, Abdelsalam [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals (KFUPM), P.O. Box 874, Dhahran 31261 (Saudi Arabia)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Mass transfer downstream of orifices was numerically and experimentally investigated. Black-Right-Pointing-Pointer The surface wear pattern is measured and used to validate the present numerical results. Black-Right-Pointing-Pointer The maximum mass transfer coefficient found to occur at approximately 2-3 pipe diameters downstream of the orifice. Black-Right-Pointing-Pointer The FAC wear rates were correlated with the turbulence kinetic energy and wall mass transfer in terms of Sherwood number. Black-Right-Pointing-Pointer 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{sub 4}{center_dot} Vulgar-Fraction-One-Half H{sub 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

  18. 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

  19. 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

  20. Infrared thermography as option for evaluating the treatment effect of percutaneous transluminal angioplasty by patients with peripheral arterial disease.

    Science.gov (United States)

    Staffa, Erik; Bernard, Vladan; Kubicek, Lubos; Vlachovsky, Robert; Vlk, Daniel; Mornstein, Vojtech; Bourek, Ales; Staffa, Robert

    2017-02-01

    Aim of this study was to evaluate the possible use of infrared thermography as a supplementary method to the ankle-brachial index used in assessing the treatment effect of percutaneous transluminal angioplasty. The study included 21 patients, mean age was 60.22 years. Healthy control group included 20 persons, mean age was 55.60 years. Patients with symptomatic peripheral arterial disease (Fontaine stages I-III) were admitted for endovascular treatment by percutaneous transluminal angioplasty. Thermal images and ankle-brachial index values were obtained before and after treatment by percutaneous transluminal angioplasty. Median temperature change in the treated limb was 0.4℃, for non-treated limb was -0.5℃. The median value of ankle-brachial index in the treated limb increased by 0.17 from 0.81 after the procedure. The median value of ankle-brachial index in the non-treated limb decreased by 0.03 from the value of 1.01. Significant difference between treated limb and non-treated limb in change of ankle-brachial index was found with p value = .0035. The surface temperature obtained by the infrared thermography correlates with ankle-brachial index. We present data showing that the increase of ankle-brachial index is associated with increase of skin temperature in the case of limbs treated by percutaneous transluminal angioplasty. Our results also suggest potential of the use of infrared thermography for monitoring foot temperature as a means of early detection of onset of foot ischemic disorders.

  1. 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...

  2. Estenose arterial pós-transplante hepático: tratamento com angioplastia transluminal percutânea

    Directory of Open Access Journals (Sweden)

    Néstor Hugo Kisilevzky

    Full Text Available Vascular complications after liver transplantation include oclusion or stenosis at the sites of anastomosis in the hepatic artery, portal vein, and vena cava. Balloon angioplasty of these stenosis carries little risk and is a useful procedure for the treatment of these problems. The purpose of this paper was to assess whether percutaneous transluminal angioplasty can help to prolong allograft survival and impruve allograft function in patient with hepatic artery stenosis after liver transplantation. We report a 43-year-old mate with stenosis of hepatic artery anastomosis after liver transplantation. An abrupt elevation of liver enzymes and serum bilirrubin levels was noted on the fifth postoperative month. The patient underwent percutaneous liver biopsy, which revealed important ductal depletion due to hypoperfusion, even though Doppler ultrasound examination demonstrated arterial flow. An angiogram confirmed severe stenosis of the arterial anastomosis with poor intraparenchymal arterial perfusion pattern. In an attempt to preserve the graft, a percutaneous transluminal angioplasty was performed using microballoons mounted on a hydrophylic micro guidewire. Intervention proceeded without complications. Liver enzimes and bilirrubin levels decreased within twenty-four hours of angioplasty. Normal levels were achieved after one week. Seven month after angioplasty, the patient is in a optimal clinical condition with no signs of graft impairment. We conclude that percutaneous transluminal angioplasty of hepatic artery stenosis after liver transplantation is relatively safe and may help decrease allograft loss.

  3. Low frequency sound absorption of orifice plates, perforated plates and nozzles

    Science.gov (United States)

    Salikuddin, M.; Plumblee, H. E., Jr.

    1980-01-01

    Analyses of impulse time history data from acoustic transmission tests for conical nozzles attached to a pipe show internal reflections from the solid contraction and open area tend to cancel. To gain understanding of the opposing reflections, tests were conducted by replacing the conical nozzles with orifice plates. The primary variable was the open to solid area ratio. Internal reflection coefficient data reveal that, at an area ratio of 10-12%, the low frequency internal reflection is reduced from unity to about 0.2. Based on comparisons of far-field and internal data, acoustic energy is not conserved. Results are presented for complex reflection coefficient and far-field noise for a series of orifice and perforated plate configurations.

  4. 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

  5. A sticky situation: management of spray polyurethane foam insulation in body orifices.

    Science.gov (United States)

    Sowerby, Robert J; Sowerby, Leigh J; Vinden, Chris

    2011-11-01

    Spray polyurethane foam insulation is commonly used in the construction industry to fill gaps, seal, and insulate. We present three cases of intentional spray foam insertion in body orifices and discuss the management of such situations in the emergency department. This series includes a case of oral foam insertion used in a suicide attempt by suffocation and two cases of rectal insertion. All of these cases had potential long-term consequences; one was life-threatening. To our knowledge, this is the first published report on the medical management and removal of foam insulation from body orifices. In all three cases, the foam insulation material was successfully removed after allowing the material to harden.

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

    OpenAIRE

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

    2015-01-01

    Background 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. Methods 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 t...

  7. Correlation between flow accelerated corrosion and wall shear stress downstream from an orifice

    International Nuclear Information System (INIS)

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

    2013-01-01

    Flow accelerated corrosion (FAC) thinning rate downstream from an orifice was measured under different velocity conditions in a high-temperature water test loop to understand the effects of flow velocity on FAC thinning rate. The FAC tendency differed downstream and upstream from the orifice. The metal loss increased linearly with time downstream from the orifice, though metal loss rate gradually decreased with time upstream. FAC rate increased as flow velocity increased, particularly from 1D to 3D. The maximum FAC thinning rate increased in proportional to the 0.51th power of the mean cross-sectional velocity in this experiment. The root mean square (RMS) of wall shear stress predicted by large eddy simulation (LES) had a clear relationship with FAC thinning rate. This result indicated that FAC thinning rate can be described as a function of the wall shear stress. Additionally, the mass transfer coefficient estimated from the RMS of wall shear stress had an almost linear correlation with FAC thinning rate. (author)

  8. 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.

  9. Effect of chamfer geometry on the pressure drop of perforated plates with thin orifices

    International Nuclear Information System (INIS)

    Barros Filho, José A.; Santos, André A.C.; Navarro, Moysés A.; Jordão, Elizabete

    2015-01-01

    Highlights: • CFD estimation of pressure drop of perforated plates with chamfered thin orifices. • Different chamfer geometric features evaluated. • Calculation validated against reduced scale experiments. - Abstract: Perforated plates with thin orifices is one of the options under considerations to be used in the debris filtering bottom end pieces for the next generation of fuel assemblies for the Brazilian nuclear plants. The increase in pressure drop can be drastically reduced by optimizing the chamfer geometries. This paper describes the development and validation of a procedure devised to use Computational Fluid Dynamics (CFD) to accurately estimate the pressure drop of water flow through perforated plates with chamfered thin orifices. The procedure comprises a scaled down calculation domain, grid configuration and a set of numerical solution parameters. The validation was performed against experiments with a set of plates with different chamfer geometric features like position (inlet, outlet and both sides), angles and sizes. Three turbulence models were evaluated with the standard k–ε giving the best result. For the range of parameters evaluated here the pressure drop decrease of a two sided chamfer plate can be estimated as a sum of both inlet and outlet chamfers individually. In both cases the pressure drop decreases rapidly for small chamfers and more slowly for larger chamfers. In the flat regions the chamfer angle has little influence at the inlet and is more important at outlet

  10. 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)

  11. 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

  12. Percutaneous transluminal angioplasty in the treatment of renovascular hypertension: sequential prospective study

    Directory of Open Access Journals (Sweden)

    Fausto Miranda Jr.

    Full Text Available OBJECTIVE: to evaluate the use of percutaneous transluminal renal angioplasty (PTRA in the treatment of renal vascular hypertension. DESIGN: sequential prospective PTRA treatment of severe arterial hypertension, screening by the captopril test, confirmed by renal arteriography, and the result evaluated by post-PTRA arteriography, blood pressure measurement and renal function. SITE: Vascular Surgery, angioradiology sector, and Nephrology outpatients department of the Federal University of São Paulo - Paulista School of Medicine, São Paulo, Brazil, a tertiary health-care institution. PARTICIPANTS: PTRA was employed on 32 patients screened by clinical examination, captopril test and renal arteriography. EVALUATION: PTRA results were evaluated by the criteria of the Cooperative Study of Renovascular Hypertension. RESULTS: after PTRA the completion arteriography showed no renal stenosis in 24 patients (75%, residual stenosis (20-50% in 3 (9.4% and no change in 5 (15.6%. The blood pressure results were: 3 patients (9.4% were cured, 24 (75% improved: and 5 (15.6% were unchanged. We observed normal renal function before and after PTRA in 25 patients (78%; altered pre- and improved post-PTRA in 2 (6.3%; post-PTRA remained unaltered in 2 (6.3%; and altered pre- and worsened post-PTRA in 3 (9.4%. Recurrence of stenosis occurred in one patient after 8 months. CONCLUSIONS: PTRA is a convenient procedure, relatively safe and an effective complementary method of medical therapy for controlling renovascular hypertension.

  13. 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).

  14. 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.

  15. [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.

  16. Assessment Of Coronary Artery Aneurysms Using Transluminal Attenuation Gradient And Computational Modeling In Kawasaki Disease Patients

    Science.gov (United States)

    Grande Gutierrez, Noelia; Kahn, Andrew; Shirinsky, Olga; Gagarina, Nina; Lyskina, Galina; Fukazawa, Ryuji; Owaga, Shunichi; Burns, Jane; Marsden, Alison

    2015-11-01

    Kawasaki Disease (KD) can result in coronary artery aneurysms (CAA) in up to 25% of patients, putting them at risk of thrombus formation, myocardial infarction and sudden death. Clinical guidelines recommend CAA diameter >8 mm as the arbitrary criterion for initiating systemic anticoagulation. KD patient specific modeling and flow simulations suggest that hemodynamic data can predict regions at increased risk of thrombosis. Transluminal Attenuation Gradient (TAG) is determined from the change in radiological attenuation per vessel length and has been proposed as a non-invasive method for characterizing coronary stenosis from CT Angiography. We hypothesized that CAA abnormal flow could be quantified using TAG. We computed hemodynamics for patient specific coronary models using a stabilized finite element method, coupled numerically to a lumped parameter network to model the heart and vascular boundary conditions. TAG was quantified in the major coronary arteries. We compared TAG for aneurysmal and normal arteries and we analyzed TAG correlation with hemodynamic and geometrical parameters. Our results suggest that TAG may provide hemodynamic data not available from anatomy alone. TAG represents a possible extension to standard CTA that could help to better evaluate the risk of thrombus formation in KD.

  17. Transluminal Attenuation Gradient for Thrombotic Risk Assessment in Kawasaki Disease Patients with Coronary Artery Aneurysms

    Science.gov (United States)

    Grande Gutierrez, Noelia; Kahn, Andrew; Burns, Jane; Marsden, Alison

    2014-11-01

    Kawasaki Disease (KD) can result in coronary aneurysms in up to 25% of patients if not treated early putting patients at risk of thrombus formation, myocardial infarction and sudden death. Clinical guidelines for administering anti-coagulation therapy currently rely on anatomy alone. Previous studies including patient specific modeling and computer simulations in KD patients have suggested that hemodynamic data can predict regions susceptible to thrombus formation. In particular, high Particle Residence Time gradient (PRTg) regions have shown to correlate with regions of thrombus formation. Transluminal Attenuation Gradient (TAG) is determined from the change in radiological attenuation per vessel length. TAG has been used for characterizing coronary artery stenoses, however this approach has not yet been used in aneurysmal vessels. The aim of this study is to analyze the correlation between TAG and PRTg in KD patients with aneurysms and evaluate the use of TAG as an index to quantify thrombotic risk. Patient specific anatomic models for fluids simulations were constructed from CT angiographic image data from 3 KD aneurysm patients and one normal control. TAG values for the aneurysm patients were markedly lower than for the non-aneurysmal patient (mean -18.38 vs. -2). In addition, TAG values were compared to PRTg obtained for each patient. Thrombotic risk stratification for KD aneurysms may be improved by incorporating TAG and should be evaluated in future prospective studies.

  18. Effect of percutaneous transluminal angioplasty in insufficiency of arteriovenous fistula for hemodialysis

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chung Sik; Goo, Dong Erk; Kim Kyeung Suk; Kim, Hun Hwa; Kim, Dae Ho; Choi, Deuk Lin; Mun, Chul; Lee, Hee Bal [Soonchunhyang Univ. College of Medicine, Asan (Korea, Republic of)

    1999-06-01

    To evaluate the effectiveness of percutaneous transluminal angioplasty(PTA) and to determine the factors affecting the long-term patency rate in the management of insufficient hemodialytic arteriovenous fistula(AVF). Forty-nine cases of insufficient hemodialytic AVF were treated in 44 patients(native AVF:20, graft AVF:29, M:17, F:27, Age:22-70 years). In 28 thrombus patients, thrombolysis was performed with urokinase, and was followed by PTA. The initial success rate and complications of PTA were evaluated. According to the site and length of the stenosis, type and age of the AVF, the presence or abscence of thrombus, a history of diabetic mellitus, the patient's age, and the duration of renal failure, patency rates were compared within each subgroup using the Kaplan-Meier logrank test. The initial success rate of PTA for insufficient hemodialytic AVF was 88%(43/49), the patency rate of PTA was 67% at 6 months, and 50% at 12 months. The initial success rate of thrombolysis was 89%(25/28). The complication rate of PTA was 12%(6/49), of which five cases were vein rupture, and one was subcutaneous hematoma. Statistically, the patency rates in the above mentioned subgroups were not significantly different. PTA with or without thrombolysis offers safe and effective management of insufficient hemodialytic AVF.

  19. 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)

  20. Diabetic foot wounds in haemodialysis patients: 2-year outcome after percutaneous transluminal angioplasty and minor amputation.

    Science.gov (United States)

    Matsuzaki, Kyoichi; Miyamoto, Akira; Hakamata, Naohiro; Fukuda, Masahiro; Yamauchi, Yasutaka; Akita, Takako; Kuhara, Ryoji; Tezuka, Shingo

    2012-12-01

    Critical limb ischaemia (CLI) is known to be associated with high mortality. In some patients, surgery cannot be performed due to high risk of perioperative death and complications. In other cases, there is only pain at rest but no wound. Therefore, it is difficult to accurately predict the prognosis of individual patients. We examined the prognosis of CLI cases in which therapeutic footwear was made for ambulation after wounds healed. The subjects were 31 haemodialysis patients with diabetic foot wounds, which were treated with percutaneous transluminal angioplasty and minor amputation. The subjects were 22 men and 9 women. Female patients were significantly older than male patients (P = 0.046). Two-year postoperative outcomes were survival in 19 patients and death in 12 patients. Eight of twelve deceased patients had a history of coronary intervention. There were 8 deaths among 13 patients with such history, indicating a marginally significant increase in the mortality rate (P = 0.060). Re-amputation was performed in 6 of 19 patients who survived. Two years postoperatively, 41.9% of patients overall survived without re-amputation. It is important to increase the number of cases for further study to improve the well-being of CLI patients and to examine medical economics. © 2012 The Authors. International Wound Journal © 2012 Blackwell Publishing Ltd and Medicalhelplines.com Inc.

  1. Effect of percutaneous transluminal angioplasty on tissue oxygenation in ischemic diabetic feet.

    Science.gov (United States)

    Kim, Hong-Ryul; Han, Seung-Kyu; Rha, Seung-Woon; Kim, Hyun-Surk; Kim, Woo-Kyung

    2011-01-01

    Percutaneous transluminal angioplasty (PTA) has been performed as an alternative to bypass surgery for improving tissue oxygenation in ischemic diabetic feet because the former is less invasive than the latter. The purpose of this study was to evaluate the effect of PTA on tissue oxygenation in ischemic diabetic feet. This study included 29 ischemic diabetic feet, as determined by a transcutaneous oxygen pressure (TcPO(2) )50%, respectively. For evaluation of tissue oxygenation, the foot TcPO(2) was measured before PTA and weekly for 6 weeks after PTA. Immediately after PTA, 26 feet were evaluated as being successful and the remaining three as acceptable. Before PTA, the average foot TcPO(2) was 12.7 ± 8.9 mmHg. The TcPO(2) values were increased to 43.6 ± 24.1, 51.0 ± 22.6, 58.3 ± 23.0, 61.3 ± 24.2, 59.0 ± 22.2, and 53.8 ± 21.0 mmHg 1, 2, 3, 4, 5, and 6 weeks after PTA, respectively (pdiabetic feet. The maximal level of tissue oxygenation was measured on the fourth week following PTA. © 2010 by the Wound Healing Society.

  2. Percutaneous transluminal angioplasty in severe diabetic foot ischemia: outcomes and prognostic factors.

    Science.gov (United States)

    Jacqueminet, S; Hartemann-Heurtier, A; Izzillo, R; Cluzel, P; Golmard, J L; Ha Van, G; Koskas, F; Grimaldi, A

    2005-09-01

    To evaluate the outcomes of severe ischemic diabetic foot ulcers for which percutaneous transluminal angioplasty (PTA) was considered as the first-line vascular procedure. Factors associated with successful PTA were sought. In 32 consecutive diabetic patients with foot ulcers and severe limb ischemia, PTA was performed if feasible; if not, primary bypass grafting was done when feasible. All patients were followed until healing or for at least one year. Patients with worsening ulcers after PTA underwent bypass grafting. Clinical and angiographic factors influencing outcomes after PTA were sought by univariate and multivariate analysis. PTA was done in 25 of the 32 (78%) patients, and considered clinically successful in 13 (52%). After 1 year, the healing rate was 70% and the limb salvage rate 90%. Successful PTA was significantly associated with a higher post-PTA transcutaneous oxygen pressure (P = 0.03) and presence of at least one patent pedal vessel (P = 0.03) in the univariate analysis; only a patent pedal vessel was significant in the multivariate analysis. Primary PTA in diabetic patients with severe ischemic foot ulcers provides similar outcomes to usual results obtained in severe ischemia in absence of diabetes. The presence of one patent pedal vessel on arteriography before PTA is the best prognostic factor.

  3. 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)

  4. Incomplete revascularization in multivessel percutaneous transluminal coronary angioplasty: the role for stress thallium-201 imaging

    International Nuclear Information System (INIS)

    Breisblatt, W.M.; Barnes, J.V.; Weiland, F.; Spaccavento, L.J.

    1988-01-01

    Evaluation of patients with multivessel coronary disease for percutaneous transluminal coronary angioplasty raises the question: Is incomplete revascularization an acceptable procedure in these patients, or does complete revascularization need to be performed, as in coronary artery bypass grafting? To provide an answer the present study utilized exercise thallium imaging as a guide to the performance of angioplasty in 85 patients with multivessel coronary disease. Preangioplasty exercise thallium imaging helped to identify the primary stenosis (culprit lesion) in 93% of patients. Two weeks to 1 month after dilation of this lesion, repeat thallium imaging identified two patient groups: Group 1, 47 patients with no evidence of ischemia in a second vascular distribution and Group 2, 38 patients with evidence of further angioplasty. In Group 2 47% of patients had angioplasty of a second vessel and 79% required multivessel angioplasty at 1 year follow-up. In contrast, only six Group 1 patients (13%) required angioplasty of a second vessel at 1 year. Thus, incomplete revascularization may be an acceptable approach in many patients with multivessel coronary disease. Stress thallium-201 imaging may be a useful technique in the evaluation and management of these patients

  5. Primary percutaneous transluminal coronary angioplasty in the acute infarction of the right ventricle

    Directory of Open Access Journals (Sweden)

    Gligić Branko

    2003-01-01

    Full Text Available Background. Predilection site for the acute myocardial infarction of the right ventricle, (AMI-RV is the upper third of the right coronary artery and for this reason such an infarction is followed by numerous complications, primarily by conduction disorders and very often by sudden and rapid cardiogenic shock development. Methods. Primary percutaneous transluminal coronary angioplasty (PPTCA was performed on three patients in whom the acute infarction of the right ventricular was diagnosed and who had been hospitalized six hours after the beginning of chest pain. In all three patients intracoronary stent was implanted. On the admission patients had been in the threatening cardiogenic shock, with the prominent chest pain and with the elevation of ST-segment in V4R>2 mV. In the course of intervention patients were administered low-molecular intracoronary heparin with direct platelet glycoprotein IIb/IIIa inhibitors (abciximab, according to the established procedure applied in such cases. Results. The complete dilatation of the infarcted artery was established with the signs of reperfusion and the further clinical course was completely normal, there was no heart failure and patients had no subjective difficulties. Conclusion. Invasive approach in the treatment of AMI-RV is justifiable, and possibly the therapy of choice of these patients, providing well trained and equipped team is available.

  6. 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)

  7. Measurement of flow accelerated corrosion rate at an elbow pipe and combination effect of an upstream orifice

    International Nuclear Information System (INIS)

    Utanohara, Yoichi; Kamahori, Koichi; Nakamura, Akira; Murase, Michio

    2016-01-01

    Flow accelerated corrosion (FAC) rates at an elbow pipe with the diameter of D = 50 mm were measured by using corrosion sensors made of carbon steel. In addition, FAC rates at the elbow with an upstream orifice were measured to investigate the enhancement of FAC due to pipe geometries. The diameter ratio of the orifice was 0.5. The water temperature was 150°C, the mean cross-sectional velocity was 4.98 m/s, the dissolved oxygen concentration was under 0.2 μg/kg, and pH was nearly neutral (about 7.0) at room temperature. The FAC rate was smaller at the intrados of the elbow pipe than at other circumferential locations due to low flow velocity near the inner surface. The ratio of the maximum FAC rate at the elbow pipe to the FAC rate in the straight pipe was about 3.7 without the upstream orifice and about 15.4 with the upstream orifice. This showed that the orifice significantly affected the FAC rate at the elbow pipe because of the short distance of 2.65D between the orifice and the elbow pipe. (author)

  8. NOTES: a review.

    Science.gov (United States)

    Mansard, Magnus Jayaraj; Reddy, D Nageshwar; Rao, G Venkat

    2009-01-01

    A few years ago a new approach to performing abdominal surgery was presented, i.e. via the natural body orifices using endoscopes. The interest and research in this approach progressed very rapidly, in spite of the initial skepticism. It was initially demonstrated in animal models, then in human beings and has now very nearly become routine practice. This article reviews the development of natural orifice transluminal endoscopic surgery (NOTES), its benefits and the hurdles we have yet to overcome.

  9. [Renal artery stenosis after transplantation: treatment using percutaneous transluminal angioplasty and placement of an expandable metal luminal prosthesis].

    Science.gov (United States)

    Guzmán-Rodríguez, J Hugo; Plata-Muñoz, Juan José; Mancilla, Eduardo; Dorantes, Joel; Narváez, René; Martínez, Raúl; Tielve, Manuel; Bezaury, Paulina; Correa-Rotter, Ricardo; Alberú, Josefina

    2003-01-01

    Transplant renal artery stenosis (TRAS) is a cause of severe post transplant hypertension with a widely variable reported incidence from 1 to 25%. We herein report 3 cases of endoluminal stent placement after percutaneous transluminal angioplasty for treatment of TRAS. Clinical and laboratory findings during their follow-up, suggestive of TRAS included: elevated mean blood pressure, bruit over the graft area(2/3), and increase in serum creatinine (2/3). Doppler sonography, radioisotope renography and arteriography were performed to confirm TRAS diagnosis. The series includes 2 female and 1 male patients; the time elapsed between transplantation and TRAS diagnosis was 25 d, 12 and 65 months, respectively. All grafts were from living related donors. Patients received at least 3 antihypertensive drugs without adequate blood pressure control. Vascular anastomosis was end to end from the renal to the hypogastric artery in two cases, and end to side to the external iliac artery in the other one. After the diagnosis of TRAS, percutaneous transluminal angioplasty with endoluminal metallic Palmaz stent placement was accomplished in the three cases. No complications occurred during or after the procedures. Beneficial clinical results were obtained in all cases documented by a decrease in both: serum creatinine, and mean blood pressure. Average follow-up after stent placement was 13, 19 and 36 months, respectively without evidence of stenosis recurrence Percutaneous transluminal angioplasty with stent placement is a safe and effective treatment for TRAS associated hypertension and renal dysfunction. Extended follow-up is necessary to evaluate long-term efficacy and safety of this procedure.

  10. Percutaneous transluminal angioplasty of chronic arterial occlusive disease below the knee joint

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Woong; Kim, Jae Kyu; Park, Soo Min; Kim, Yun Hyeon; Kang, Heoung Keun [Chonnam Univ. Medical School, Kwangju (Korea, Republic of)

    1996-01-01

    The purpose of this study was to determine the safety and efficacy of the percutaneous transluminal angioplasty(PTA) in patients with chronic arterial occlusive disease below the knee joint. We retrospectively analyzed the results of 36 procedures in 16 patients. There were 15 men and one woman, aged 57-75 years(mean, 62 years). Indications were disabling claudication (SVS/ISCVS grade 1, category 3) in five cases, rest pain(grade 2, category 4) in three cases, and non-healing ulceration or gangrene(grade3, category 5) in eight cases. PTA was performed by using small vessel balloon catheter of 2-4 mm and 3 mm monorail balloon catheter in tibioperoneal vessels and 5-6 mm balloon catheter in distal popliteal artery and tibioperoneal trunk. Combined thrombolytic therapy with Urokinase was performed in 14 patients. Involved infrapopliteal vessels were four distal popliteal arteries, 15 tibioperoneal trunks, six anterior tibial arteries, five posterior tibial arteries, and seven peroneal arteries. Technical success was determined when post-PTA angiogram showed less than 30% of residual stenosis. Clinical success was defined as improvement of clinical symptoms, such as disappearance of claudication or rest pain, and healing of ulcereation. Technical success was achieved in 30 of 36 arteries(83%). Clinical success was achieved in 12 of 16 patients(75%) at an average follow-up of 13.3 months(range, 2-46 months). Clinical success rate was 100% in grade 1 category 3 patients, 67% in grade 2 category 4 patients, and 63% in grade 3 category 5 patients. Complication included two distal emboli, one vessel rupture, one vessel thrombosis, and one occluding intimal flap. PTA was an effective method for treatment of chronic arterial occlusive disease below the knee joint and considered as the procedure of first choice. Severe claudicant(grade1) should be included in the indication of the tibioperoneal PTA.

  11. 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.

  12. [Application of percutaneous transluminal angioplasty in the surgical treatment of patients with diabetic feet].

    Science.gov (United States)

    Gao, Y; Cui, Z J; Shi, X; Guo, P F; Meng, Q N; Yang, G Y; Yang, R Q

    2016-08-20

    To explore the application of percutaneous transluminal angioplasty (PTA) in the surgical treatment of patients with diabetic feet. The clinical data of 83 patients with diabetic feet, 95 limbs (95 wounds) in total, hospitalized in our unit from September 2011 to September 2014, conforming to the study criteria, were retrospectively analyzed. Patients were divided into conventional treatment group (CT, n=43, 51 wounds) and PTA group (n=40, 44 wounds) according to whether receiving PTA treatment or not. Patients in two groups received conventional debridement after admission, and patients in PTA group received another PTA treatment before debridement. Granulation growing well rates of wounds of patients in two groups were calculated on post debridement day (PDD) 3, 6, 9, and 12. Two stage preoperative preparation time of wounds of patients in two groups was recorded. Status of free skin graft survival of wounds and wound healing of patients in two groups were recorded according to the grade of Wagner. Values of ankle-brachial index (ABI) and ulcer recurrence of patients in two groups checked every month during follow-up time of half a year were recorded. Data were processed with chi-square test and t test. Granulation growing well rate of wounds of patients in group CT rose slowly after treatment, which was less than 40% on PDD 12. Granulation growing well rate of wounds of patients in PTA group rose significantly on PDD 9 and all the granulation grew well on PDD 12. On PDD 9 and 12, Granulation growing well rates of wounds of patients in PTA group were significantly higher than those in group CT (with χ(2) values respectively 30.008 and 47.810, P values below 0.01). Two stage preoperative preparation time of wounds of patients in group CT [(24±10) d] was obviously longer than that in PTA group [(15±3) d, t=5.709, Pdiabetic foot.

  13. Transluminal Nd:YAG laser embolysis: A reasonable method to reperfuse occluded branch retinal arteries

    Directory of Open Access Journals (Sweden)

    Stanca Horia T.

    2014-01-01

    Full Text Available Introduction. Central retinal artery occlusion (CRAO and branch retinal artery occlusion (BRAO result in partial or complete retinal ischemia and sudden loss of vision; at this moment, there is no effective therapy for CRAO and BRAO. Transluminal Nd:YAG laser embolysis (TYE represents a therapeutic approach used for retinal vascular occlusive diseases. The main indication is branch retinal artery occlusion with visible embolus; for central retinal artery occlusion this tehnique is hardly applicable. The principle of this method consists of intravascular embolus breakage using the 1064 nm Nd:YAG laser, focused on the embolus surface. Case report. We presented 5 cases with BRAO, 3 with infero-temporal and 2 with supero-temporal BRAO, all of them treated with TYE, with variable results. All the patients had a visible embolus within the BRA, the laser applications being delivered directly to the embolus. Conclusion. Despite our short-term experience regarding this therapeutical approach, we can resume that the moment of emboli distruction, as close as possible to the onset of the occlusion, is decisive for regaining vision and that applying the procedure correctly is superior to observation in most cases. Worldwide experience with TYE is still limited, but the technique seems feasible also when treating CRAO caused by visible emboli on the optic disc surface. This most certainly calls for random trials for identifying precisely the role of TYE in treatment of retinal occlusion pathology, though the relatively small number of properly diagnosed cases affects this objective. In all cases, the risks of TYE must be weighed against the possibility of severe and permanent loss of vision secondary to retinal artery occlusions.

  14. 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

  15. 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...

  16. 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

  17. Plate-type acoustic metamaterial with cavities coupled via an orifice for enhanced sound transmission loss

    Science.gov (United States)

    Ang, Linus Yinn Leng; Koh, Yong Khiang; Lee, Heow Pueh

    2018-01-01

    Membrane-type acoustic metamaterials generally involve a heavy platelet attached to a pretensioned membrane. Their acoustical performance is characterised solely based on the resonant behaviour of the membrane-platelet assembly. However, typical designs may pose manufacturing issues if extended in scale for industrial applications. Examples include the spatial consistency of the platelet(s), the uniformity of the membrane pretension, and the durability of the membrane—not to mention stress relaxation. As large-scale designs are recently gaining interest, it is imperative to address the shortcomings for manufacturability. This study presents a proof-of-concept design using tensionless membranes without any platelets. The results showed that the acoustical performance could be complemented by the coupling effect between two enclosed cavities via an orifice. The orifice diameter could serve as a tuning parameter for broadband or narrowband transmission loss at selected frequencies. Consequently, the proposed design could address the shortcomings of membrane-type acoustic metamaterials and complement their acoustical performance with the additional feature.

  18. 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.

  19. 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

  20. Short term evolution of the percutaneous transluminal angioplasty with long balloon for the treatment of critical limb ischemia

    International Nuclear Information System (INIS)

    Qin Yonglin; Deng Gang; Guo Jinhe; He Shicheng; Fang Wen; Zhu Guangyu; Teng Gaojun

    2008-01-01

    Objective: To evaluate the feasibility, safety and short term efficacy of percutaneous transluminal angioplasty with long balloon for the treatment of critical lower limb ischemia (CLI). Methods: Data of 21 patients with critically ischemic limbs, treated with percutaneous transluminal angioplasty (PTA) with long balloon between January and June 2007 were collected and analyzed retrospectively. Balloon with different length was selected according to the extent of the lesions. Procedural success rate, early complications and continued clinical improvement were observed. Primary patency, cumulative patency and limb salvage with survival were statistically calculated. Results: Two cases of pseudoaneurysm formation occurred as the early processing complication at the puncture sites. Procedural success rates were different and associated with the sites and severities of stenosis, but much lower for crural arteries with occlusive lesion. No severe dissection occurred after PTA. Clinical success rate was 90.5%. The average hospital stay was 6 days. Primary patency, secondary patency and limb salvage were 95.2%, 100% and 100% respectively, at 6 months. Conclusions: PTA with long balloon is safe, effective and feasible in patients with critical lower limb ischemic disease, providing good limb salvage and less complications. (authors)

  1. 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.

  2. 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

  3. 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

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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

  7. 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)

  8. A combination of left ventricular noncompaction and double orifice mitral valve

    Directory of Open Access Journals (Sweden)

    Song Ze-Zhou

    2009-03-01

    Full Text Available Abstract A 24-year-old woman admitted with mild chest distress associated with activity without chest complaint for twenty days. Two orifices were visible at the level of the mitral valve with a transthoracic short-axis view of the two-dimensional and three-dimensional echocardiography. The left ventricle was mildly dilatated and the left ventricular wall was thickened, especially at the apex and anterolateral wall, and appeared sponge-like. There were numerous, excessively prominent trabeculations associated with intertrabecular recesses. Although the coexistence of NVM and DOMV could be a coincidence, we believe that both defects were probably caused by a developmental arrest of the left ventricular myocardium in the present case.

  9. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  10. Cholecystectomie: transvaginaal, transgastrisch, transumbilicaal of 'gewoon' laparoscopisch

    NARCIS (Netherlands)

    Gouma, Dirk J.

    2011-01-01

    Natural Orifice Transluminal Endoscopic Surgery (NOTES), transvaginal cholecystectomy in particular, is a new development in minimally invasive surgery. The relatively limited studies conducted have shown good short-term results. The benefits, in terms of cosmetic results and pain, should be weighed

  11. Author Details

    African Journals Online (AJOL)

    Mouafo Tambo, F.F. Vol 11, No 1 (2017) - Articles Quoi de neuf: Management of congenital scoliosis. Abstract · Vol 11, No 2 (2017) - Quoi de neuf / What is new? Natural orifice transluminal endoscopic surgery (notes): A new challenge for surgeons in Africa Abstract. ISSN: 1997-3756. AJOL African Journals Online.

  12. Feasibility Study of EUS-NOTES as a Novel Approach for Pancreatic Cancer Staging and Therapy

    DEFF Research Database (Denmark)

    Săftoiu, Adrian; Bhutani, Manoop S; Vilmann, Peter

    2012-01-01

    Background/Aims: EUS guided Natural Orifice Transluminal Endoscopic Surgery (NOTES) could be a potentially viable approach for pancreatic surgery. EUS-guided access through the stomach wall may prove to be a safe and effective method for accessing the pancreas. The aim of the study was to assess...

  13. 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

  14. 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.

  15. Percutaneous transluminal septal alcoholization for the treatment of refractory hypertrophic obstructive cardiomyopathy: initial experience in the Federal District

    Directory of Open Access Journals (Sweden)

    Evandro César Vidal Osterne

    2003-04-01

    Full Text Available OBJECTIVE: To analyze the efficacy of percutaneous transluminal septal alcoholization in the treatment of refractory obstructive hypertrophic cardiomyopathy (HOC. METHODS: The patients were referred for alcoholization after Doppler echocardiography. Before and after alcoholization, the intraventricular pressure gradient was recorded. Alcoholization was performed with a 3mL injection of absolute alcohol through a coronary angioplasty balloon catheter. The procedure was concluded after a significant reduction or abolition of the pressure gradient. RESULTS: Of 22 patients, 18 (81.8% successfully concluded the procedure with a reduction in intraventricular pressure gradient at baseline (from 67.6±24.2 mmHg to 3.8± 1.9 mmHg, p<0.005 and after extrasystole (from 110.4± 24.2 mmHg to 9.6±2.6 mm Hg, p<0.005. A significant reduction in mean interventricular septal thickness (from 2± 0.3 mm to 1.7±0.2 mm, p<0.005 and in peak pressure gradient (from 90.7±23.5 mmHg to 6.1±1.4 mmHg, p<0.005 was observed on Doppler echocardiography after 6 months, when all patients were in functional class I. The most frequent acute complication, present in 11% of the patients, was the need for definitive pacing implantation. Relapse of the symptoms and reappearance of the pressure gradient occurred in 16.6% of the patients. One patient (5.5% died probably due to a diffuse coronary spasm prior to the procedure, and another died suddenly on late follow-up. CONCLUSION: Percutaneous transluminal septal alcoholization is effective and safe in the treatment of HOC.

  16. 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)

  17. 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 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.

  18. Internal Flow and Near-Orifice Spray Visualisations of a Model Pharmaceutical Pressurised Metered Dose Inhaler

    International Nuclear Information System (INIS)

    Versteeg, H K; Hargrave, G K; Kirby, M

    2006-01-01

    The pressurised Metered Dose Inhaler (pMDI) has become the most prescribed drug delivery system for treating the respiratory diseases. However, the spray generation mechanism of these devices has not been extensively researched and there is very little information regarding the two-phase fluid dynamics associated with pre-atomisation inside the valve stem. The aim of the work presented in this paper is to provide high-quality, time-resolved imaging of the internal flow structures of pMDIs in an attempt to link the characteristics of the internal flow to external spray atomization processes. Visualisations of the aerosols in the near-orifice region findings from previous studies of commercial pMDIs and showed the following characteristics: (i) start-up transient (ii) fully developed spray with slow spray density variations and (iii) rapid spray density pulsations with large droplet production. The results clearly highlighted the potential of optical diagnostics in the development of improved accounts of the state of the flow inside a pMDI valve and its relationship with drop formation

  19. 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

  20. An experimental study on the onset of detonation downstream of a perforated plate with staggered orifices

    Science.gov (United States)

    Lin, Wei; Zhou, Jin; Lin, Zhiyong; Liu, Shijie

    2017-09-01

    The present study investigated the onset of detonation (OD) process which takes place downstream of a 0.9-mm-thick perforated plate. The orifice diameter of the plate is 1.6 mm with a blockage of 59%, and it was placed perpendicular to the axial direction of a smooth detonation tube. `Stable' mixture C2H2 + 2.5O2 + 70%Ar and `unstable' mixture C2H2 + 5N2O were tested, respectively. Ionization probes and smoked foils were used to record detonation velocities and corresponding cellular patterns. Excellent agreement of the velocity trends and smoked foil results shows that a critical pressure range exists to identify `go' and `no go' of OD downstream of the perforated plate. However, the OD mechanisms for these two gaseous mixtures are distinct: for the `stable' mixture, OD occurs in the downstream near field (6 tube diameters in this study), whereas, OD in the `unstable' mixture could also observed in the far field via the transition of deflagration to detonation after a long duration of quasi-steady regime. This distance reaches up to tens of tube diameters when close to the critical pressure.

  1. 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.

  2. 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)

  3. D0 Silicon Upgrade: Calculating Mass Flow Rates at Sub-Sonic Conditions Trhough Venturis (FT-4052-H & FT-4053-H) and an Orifice Plate (F)-2019-H)

    Energy Technology Data Exchange (ETDEWEB)

    Zaczek, Mauiusz; /Fermilab

    1996-08-15

    The purpose of this engineering note is to explain the method involved in calculating the mass flow rates through venturis and orifice plates at sub-sonic conditions. In particular, the mass flow rate calculations are required for two FLOW-DYNE venturi flow meters, serial no. 35821 and no. 35822, and an orifice plate flow meter, serial no. 35823. The two venturis, FT-4052-H and FT-4053-H, are located in the D-Zero VLPC valve box at the refrigerator and the orifice plate, FO-2019-H, is on the high pressure helium supply line in the assembly building.

  4. Performance evaluation of a developed orifice type heater for thermal compensation control at J-PARC cryogenic hydrogen system

    Science.gov (United States)

    Tatsumoto, H.; Aso, T.; Ohtsu, K.; Kawakami, Y.

    2015-12-01

    Supercritical hydrogen with a temperature of less than 20 K and a pressure of 1.5 MPa is used as moderator material at J-PARC. Total nuclear heating of 3.75 kW is generated by three moderators for a 1-MW proton beam operation. We have developed an orifice-type high-power heater for thermal compensation to mitigate hydrogen pressure fluctuation caused by the abrupt huge heat load and to reduce the fluctuation in the temperature of the supply hydrogen to less than 0.25 K. Through a performance test, we confirmed that the developed orifice-type heater could be heated uniformly and showed fast response, as expected. Furthermore, a simulation model that can describe heater behaviors has been established on the basis of the experimental data. The heater control approach was studied using the aforementioned heater simulation model and a dynamic simulation code developed by the authors.

  5. Numerical studies of manipulation and separation of Janus particles in nano-orifice based DC-dielectrophoretic microfluidic chips

    International Nuclear Information System (INIS)

    Zhao, Kai; Li, Dongqing

    2017-01-01

    The direct current dielectrophoretic (DC-DEP) manipulation and separation of polystyrene-based Janus particles and the homogeneous polystyrene particles in microchannels are numerically investigated. To induce the DEP force, a small electric potential difference is applied across the microchannel via a smaller nano-orifice on one side of the channel walls and a larger micro-orifice on the opposite channel wall. A strong non-uniform electric field gradient is generated by the asymmetric orifices, and the particles will undergo the DEP forces when moving with the flow through the vicinity of the small orifice, where the strongest electrical field gradient exists. By adjusting the electrical conductivity of the suspending solution, one kind of the particles will experience the negative DEP force while another will undergo the positive DEP force. In this way, the separation of 5 µ m Janus particles and homogeneous polystyrene particles, and the separation of 3 µ m and 5 µ m Janus particles were numerically demonstrated. Moreover, in order to further understand the dielectrophoretic motion of the Janus particles, the DC-DEP force on the Janus particles was analyzed and the effects of the electric fields, as well as the coating coverage, thickness, and electric conductivity of the Janus particles were studied. The results show that the Janus particles with gold coating coverage over 50% will experience positive DEP forces and be attracted towards the maximum electric fields. It is also found that the effect of the gold coating thickness of the Janus particles on their trajectories can be neglected when using the DC-DEP method. (paper)

  6. 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).

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  8. 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.

  9. Sulodexide as Adjunctive Therapy in Diabetic Foot Patients With Critical Limb Ischemia Treated With Percutaneous Transluminal Angioplasty.

    Science.gov (United States)

    Piaggesi, Alberto; Abbruzzese, Lorenza; Mattaliano, Chiara; Bargellini, Irene; Cicorelli, Antonello; Iacopi, Elisabetta; Lunardi, Alessandro; Coppelli, Alberto; Goretti, Chiara; Cioni, Roberto

    2014-06-01

    We evaluated the safety and efficacy of sulodexide, a biocompound of glycosamin-glicans, as adjunct medical therapy to percutaneous transluminal angioplasty (PTA) in diabetes mellitus (DM) patients with critical limb ischemia (CLI). We studied 27 consecutive DM patients with CLI successfully subjected to PTA who, on top of standard antiplatelet therapy, received sulodexide 25 mg bid, and were followed-up for 24 weeks, monitoring adverse events, transcutaneous oxygen tension (TcPO 2 ), ankle-brachial pressure index, pain, and ulcer dimension. At the end of follow-up, ulcer healing, amputation rates, and cardiovascular risk profile of patients were evaluated. Patients were compared with a historical superimposable control group that was treated for the same indications in the same way as the study group, except for sulodexide inception. No differences in ulcer healing and amputation rates were found at the end of follow-up between the groups. In the study group, TcPO 2 was significantly (P < .05) higher at the end of follow-up, and pain intensity was reduced more rapidly. Plasma fibrinogen and plasma creatinine concentration were significantly (P < .05) reduced in study group at the end of follow-up. No differences in adverse events were observed between the groups during follow-up. Our data suggest that sulodexide administration after PTA, on top of antiplatelet therapy, may improve the outcome of PTA in DM patients with CLI by improving microcirculatory function. © The Author(s) 2014.

  10. Patient effective doses during intracoronary irradiation with a Rhenium 188 full filled balloon catheter after percutaneous transluminal coronary artery

    Energy Technology Data Exchange (ETDEWEB)

    Ponce V, L.; Peix G, A.; Llerena R, L.; Santana V, L. [Instituto de Cardiologia, La Habana (Cuba); Lopez D, A. [Hospital Hermanos Amejeiras, La Habana (Cuba)

    2006-07-01

    Intracoronary irradiation with a full filled Re188 balloon catheter treatment technique (IRT) after Percutaneous Transluminal Coronary Artery (PTCA) should represent an addition patient exposure dose with respect to common PTCA procedure. Our proposes were determinate the absorbed doses and estimate the risk for fatal cancer in 25 patients (15 males, mean age: 559 years old) treated during an IRT randomized clinical trial carried out in our institution as part of IAEA technical cooperation project. 20 Gy was always the prescribed doses for each patient. The average Re188 concentrated activity used and treatment time were 5256{+-}2371 MBq/ml in 1.5-2 ml and 466{+-}195 seconds, respectively. Two thermoluminescent dosimeters were attached in the chest and pelvis for each patient treated. Calibration for attenuation and scattered radiations was done. The maximal and mean value effective dose obtained for chest patient region were 18 mSv and 15{+-}6 mSv, respectively and for pelvis patient region the results were 10 mSv and 8{+-}3 mSv, respectively. The total risk to develop fatal cancer was 0.084% for patient treated. The patient effective doses is slightly superior to those reported for common procedures as PTCA. The IRT is considered a quite safe procedure, but in order to exposure radiation level optimization the continuous review of procedure should be constantly done. (Author)

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

    Directory of Open Access Journals (Sweden)

    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.

  12. 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).

  13. 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)

  14. 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.

  15. Mechanisms of natural ventilation in livestock buildings

    DEFF Research Database (Denmark)

    Rong, Li; Bjerg, Bjarne Schmidt; 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...

  16. Surgical Repair of Mid-shaft Hypospadias Using a Transverse Preputial Island Flap and Pedicled Dartos Flap Around Urethral Orifice.

    Science.gov (United States)

    Liang, Weiqiang; Ji, Chenyang; Chen, Yuhong; Zhang, Ganling; Zhang, Jiaqi; Yao, Yuanyuan; Zhang, Jinming

    2016-08-01

    To evaluate the effects, particularly the incidence of anastomotic fistula, of a pedicled dartos flap around the urethral orifice in the treatment of urethroplasty of mid-shaft hypospadias. A total of 46 cases of congenital mid-shaft hypospadias were included in this study. The patients ranged in age from 0.7 to 25.4 years and the average was 5.8 years. The patients received penis chordee correction. A transverse preputial island flap was developed for urethral reconstruction. The proximal dartos of the urethral orifice was used to develop a pedicled dartos flap, which was transposed to cover and strengthen neourethral anastomosis. The ventral penile skin defect was repaired by another flap. The 46 patients were examined during follow-up visits for 6 months to 3 years. An anastomotic fistula was observed in one case (2.2 %). Scar healing without fistula was observed in another patient due to poor blood supply to part of the ventral penile skin. No other incidences of fistula, urethral rupture, flap necrosis, wound infections, urinary tract (meatal) stenosis, or urethral diverticulum were observed in the patients. A pedicled dartos flap around the urethral orifice can take advantage of well-vascularized local tissue to add a protective layer to the proximal aspect of the neourethral anastomosis for reducing the incidence of anastomotic fistula in mid-shaft hypospadias repair using a transverse preputial island flap. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  17. 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

  18. 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

    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...... 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...

  19. Measurements of Thermal Effects on Acoustic Screech in a Choked Circular Jet Emanating from a Sharp-Edged Orifice

    Science.gov (United States)

    Kandula, Max

    2012-01-01

    Experiments are performed in a 24.4 mm diameter choked circular hot and cold jets issuing from a sharp-edged orifice at a fully expanded jet Mach number of 1.85. The stagnation temperature of the hot and the cold jets are 319 K and 299 K respectively. The results suggest that temperature effects on the screech amplitude and frequency are manifested for the fundamental, with a reduced amplitude and increased frequency for hot jet relative to the cold jet. Temperature effects on the second harmonic are also observed.

  20. 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.

  1. Effects of percutaneous transluminal angioplasty on muscle BOLD-MRI in patients with peripheral arterial occlusive disease: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Huegli, Rolf W. [University Hospital Basel, Department of Radiology, Division of Interventional Radiology, Basel (Switzerland)]|[Kantonsspital Bruderholz, Department of Radiology, Bruderholz (Switzerland); Schulte, Anja-Carina [University of Basel, Biocenter, Basel (Switzerland); Aschwanden, Markus; Thalhammer, Christoph [University Hospital Basel, Department of Angiology, Basel (Switzerland); Kos, Sebastian; Jacob, Augustinus L.; Bilecen, Deniz [University Hospital Basel, Department of Radiology, Division of Interventional Radiology, Basel (Switzerland)

    2009-02-15

    The purpose was to evaluate the effect of percutaneous transluminal angioplasty (PTA) of the superficial femoral artery (SFA) on the blood oxygenation level-dependent (BOLD) signal change in the calf musculature of patients with intermittent claudication. Ten patients (mean age, 63.4 {+-} 11.6 years) with symptomatic peripheral arterial occlusive disease (PAOD) caused by SFA stenoses were investigated before and after PTA. Patients underwent BOLD-MRI 1 day before and 6 weeks after PTA. A T2*-weighted single-shot multi-echo echo-planar MR-imaging technique was applied. The BOLD measurements were acquired at mid-calf level during reactive hyperaemia at 1.5 T. This transient hyperperfusion of the muscle tissue was provoked by suprasystolic cuff compression. Key parameters describing the BOLD signal curve included maximum T2*(T2*{sub max}), time-to-peak to reach T2*{sub max} (TTP) and T2* end value (EV) after 600 s of hyperemia. Paired t-tests were applied for statistic comparison. Between baseline and post-PTA, T2*{sub max} increased from 11.1{+-}3.6% to 12.3{+-}3.8% (p=0.51), TTP decreased from 48.5{+-}20.8 s to 35.3{+-}11.6 s (p=0.11) and EV decreased from 6.1{+-}6.4% to 5.0{+-}4.2% (p=0.69). In conclusion, BOLD-MRI reveals changes of the key parameters T2*{sub max}, TTP, and EV after successful PTA of the calf muscles during reactive hyperaemia. (orig.)

  2. 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

  3. 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.

  4. Post-marketing surveillance in the published medical and grey literature for percutaneous transluminal coronary angioplasty catheters: a systematic review.

    Science.gov (United States)

    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.

  5. Drug-Coated Balloon Versus Standard Percutaneous Transluminal Angioplasty for the Treatment of Superficial Femoral and Popliteal Peripheral Artery Disease

    Science.gov (United States)

    Tepe, Gunnar; Schneider, Peter; Brodmann, Marianne; Krishnan, Prakash; Micari, Antonio; Metzger, Christopher; Scheinert, Dierk; Zeller, Thomas; Cohen, David J.; Snead, David B.; Alexander, Beaux; Landini, Mario; Jaff, Michael R.

    2015-01-01

    Background— Drug-coated balloons (DCBs) have shown promise in improving the outcomes for patients with peripheral artery disease. We compared a paclitaxel-coated balloon with percutaneous transluminal angioplasty (PTA) for the treatment of symptomatic superficial femoral and popliteal artery disease. Methods and Results— The IN.PACT SFA Trial is a prospective, multicenter, single-blinded, randomized trial in which 331 patients with intermittent claudication or ischemic rest pain attributable to superficial femoral and popliteal peripheral artery disease were randomly assigned in a 2:1 ratio to treatment with DCB or PTA. The primary efficacy end point was primary patency, defined as freedom from restenosis or clinically driven target lesion revascularization at 12 months. Baseline characteristics were similar between the 2 groups. Mean lesion length and the percentage of total occlusions for the DCB and PTA arms were 8.94±4.89 and 8.81±5.12 cm (P=0.82) and 25.8% and 19.5% (P=0.22), respectively. DCB resulted in higher primary patency versus PTA (82.2% versus 52.4%; P<0.001). The rate of clinically driven target lesion revascularization was 2.4% in the DCB arm in comparison with 20.6% in the PTA arm (P<0.001). There was a low rate of vessel thrombosis in both arms (1.4% after DCB and 3.7% after PTA [P=0.10]). There were no device- or procedure-related deaths and no major amputations. Conclusions— In this prospective, multicenter, randomized trial, DCB was superior to PTA and had a favorable safety profile for the treatment of patients with symptomatic femoropopliteal peripheral artery disease. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique Identifiers: NCT01175850 and NCT01566461. PMID:25472980

  6. 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.

  7. [Pulmonary vein orifice cryoablation for atrial fibrillation with mitral valve disease using a specially designed cryo-probe].

    Science.gov (United States)

    Furukawa, Hiroshi; Konishi, Toshio; Fukata, Mutsumu; Okura, Kazuhiro

    2006-05-01

    To evaluate the effectiveness of pulmonary vein orifice cryoablation (PVOC) for atrial fibrillation during mitral valve surgery. Twenty-two patients (12 men and 10 women) with mitral valve disease complicated with atrial fibrillation have been treated by PVOC since March 2000. During the mitral valve operations, all four pulmonary vein orifices were ablated using a ball-shaped cryo-probe. A newly designed cryo-probe was used for the last seven patients. Success was defined as atrial defibrillation within 6 months after the operation. The success rate was 72.7% (16/22) of all patients, and improved from 66.6% to 85.7% (6/7) in the patients treated with the new cryo-probe. The mean left atrial dimension was smaller (50.2 +/- 4.1 vs. 61.5 +/- 9.4 mm, p < 0.01), and the duration of atrial fibrillation was also shorter (27.2 +/- 42.8 vs. 138.0 +/- 95.6 months, p < 0.01) in the successful group. PVOC with mitral valve surgery is a simple and less invasive procedure, so could be an effective option for atrial fibrillation.

  8. [Planimetric measurement of the regurgitant orifice area using tridimensional transoesophageal echocardiography for aortic regurgitation, reproducibility and feasibility].

    Science.gov (United States)

    Picard, F-A; Garçon, P; Chaudeurge, A; Simion, C; Cador, R

    2014-11-01

    Aortic regurgitation is mainly evaluated by trans-thoracic echocardiography using multi-parametric qualitative and semi quantitative tools. All those parameters can fail to meet expectations, resulting in an imperfect diagnostic reliability and assessment of aortic regurgitation severity can be challenging. We sought to evaluate feasibility and intra- and inter-observer reproducibility of aortic regurgitant orifice area measured by planimetry with tridimensional trans-esophageal echocardiography on patients with at least grade 2/4 aortic regurgitation. Consecutive patients with at least grade 2/4 aortic regurgitation measured by trans-thoracic echocardiography and referred for trans-esophageal echocardiography for any reason were included. Planimetric reconstructions of regurgitant orifice area were studied and reproducibility indexes between senior and junior observers were calculated. Twenty-three patients were included in this study. Intra- and inter-observer reproducibility were excellent with an ICC of 0.95 [0.88-0.98], Ptridimensional trans-esophageal echocardiography seems to be feasible and has great intra- and inter-observer reproducibility. Reconstruction durations were compatible with a daily use. There is a need now to investigate the reliability of this measurement as compared with the reference technique. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  9. 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.

  10. Transluminal retroperitoneal endoscopic necrosectomy with the use of hydrogen peroxide and without external irrigation: a novel approach for the treatment of walled-off pancreatic necrosis.

    Science.gov (United States)

    Abdelhafez, Mohamed; Elnegouly, Mayada; Hasab Allah, M S; Elshazli, Mostafa; Mikhail, Hany M S; Yosry, Ayman

    2013-10-01

    Transluminal retroperitoneal endoscopic necrosectomy (TREN) is an attractive NOTES technique alternative to surgery for treatment of walled-off pancreatic necrosis (WOPN). The main limitations to this technique are the need for repeated sessions, prolonged external irrigation, and EUS availability. In our study, we introduced new modifications, including the use of hydrogen peroxide, and abandoning the use of EUS and external irrigation. This is a retrospective study of outcome of consecutive patients who underwent TREN for WOPN between April 2011 and August 2012. The technique included (1) non-EUS-guided transluminal drainage, and (2) direct endoscopic debridement using hydrogen peroxide and different accessories. No external irrigation was used. Ten patients were included. Initial clinical and technical success was achieved in all patients. Complete radiological success and long-term clinical efficacy was achieved in nine patients (1 patient had an inaccessible left paracolic gutter collection and died 62 days after endotherapy). Mean number of sessions was 1.4 (range 1-2). Complications included bleeding, which was self-limited in three patients and endoscopically controlled in one. All patients avoided surgery, and no recurrence was reported during median follow-up of 289 (range 133-429) days. TREN is a safe and effective treatment for WOPN and could be performed safely without EUS guidance in selected cases. Hydrogen peroxide played a major role in reduction of number of sessions and timing. External irrigation of WOPN is not necessary, if adequate debridement could be achieved.

  11. Low-Dose Paclitaxel–Coated Versus Uncoated Percutaneous Transluminal Balloon Angioplasty for Femoropopliteal Peripheral Artery Disease

    Science.gov (United States)

    Werner, Martin; Meyer, Dirk-Roelfs; Reimer, Peter; Krüger, Karsten; Jaff, Michael R.; Brodmann, Marianne

    2017-01-01

    Background: Numerous studies have reported favorable outcomes using drug-coated balloons (DCBs) for treatment of symptomatic peripheral artery disease of the superficial femoral and popliteal arteries. However, the treatment effect compared with an uncoated balloon has differed greatly among the randomized trials, with better outcomes observed with higher-dose DCBs. This European trial was designed to assess the safety and effectiveness of a next-generation low-dose (2-µg/mm2 surface dose of paclitaxel) DCB. Methods: This was a prospective, randomized, multicenter, single-blinded trial. Patients were randomized (3:1) to treatment with a low-dose DCB or an uncoated percutaneous transluminal angioplasty (PTA) balloon. The primary safety end point was a composite of freedom from device- and procedure-related death through 30 days after the procedure and freedom from target limb major amputation and clinically driven target lesion revascularization through 12 months after the procedure. The primary effectiveness end point was primary patency at 12 months. Results: Patients were randomized to treatment with a DCB (222 patients, 254 lesions) or uncoated PTA balloon (72 patients, 79 lesions) after successful predilatation. Mean lesion length was 7.2 and 7.1 cm, and 19.2% and 19.0% of lesions represented total occlusions, respectively. The primary safety end point was met, and superiority was demonstrated; freedom from a primary safety event was 94.1% (193 of 205) with DCB and 83.3% (50 of 60) with PTA, for a difference of 10.8% (95% confidence interval, 0.9%–23.0%). The primary effectiveness end point was met, and superiority of DCB over PTA was achieved (83.9% [188 of 224] versus 60.6% [40 of 66]; P<0.001). Outcomes with DCB were also superior to PTA per the Kaplan-Meier estimate for primary patency (89.0% versus 65.0% at 365 days; log-rank P<0.001) and for rates of clinically driven target lesion revascularization (5.9% versus 16.7%; P=0.014). Conclusions

  12. 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))

  13. 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

  14. 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.

  15. 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).

  16. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Planimetric Measurement of the Regurgitant Orifice Area Using Multidetector CT for Aortic Regurgitation: a Comparison with the Use of Echocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Min Hee; Choe, Yeon Hyeon; Cho, Soo Jin; Park, Seung Woo; Park, Pyo Won; Oh, Jae K. [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2010-04-15

    This study compared the area of the regurgitant orifice, as measured by the use of multidetector-row CT (MDCT), with the severity of aortic regurgitation (AR) as determined by the use of echocardiography for AR. In this study, 45 AR patients underwent electrocardiography- gated 40-slice or 64-slice MDCT and transthoracic or transesophageal echocardiography. We reconstructed CT data sets during mid-systolic to enddiastolic phases in 10% steps (20% and 35-95% of the R-R interval), planimetrically measuring the abnormally opened aortic valve area during diastole on CT reformatted images and comparing the area of the aortic regurgitant orifice (ARO) so measured with the severity of AR, as determined by echocardiography. In the 14 patients found to have mild AR, the ARO area was 0.18{+-} 0.13 cm{sup 2} (range, 0.04-0.54 cm{sup 2}). In the 15 moderate AR patients, the ARO area was 0.36 {+-} 0.23 cm{sup 2} (range, 0.09-0.81 cm{sup 2}). In the 16 severe AR patients, the ARO area was 1.00 {+-} 0.51 cm{sup 2} (range, 0.23-1.84 cm{sup 2}). Receiver-operator characteristic curve analysis determined a sensitivity of 85% and a specificity of 82%, for a cutoff of 0.47 cm{sup 2}, to distinguish severe AR from less than severe AR with the use of CT (area under the curve = 0.91; 95% confidence interval, 0.84-1.00; p < 0.001). Planimetric measurement of the ARO area using MDCT is useful for the quantitative evaluation of the severity of aortic regurgitation.

  19. In Vitro Microleakage of Mineral Trioxide Aggregate, Calcium-Enriched Mixture Cement and Biodentine Intra-Orifice Barriers

    Science.gov (United States)

    Ramezanali, Fatemeh; Aryanezhad, Sasan; Mohammadian, Fatemeh; Dibaji, Fatemeh; Kharazifard, Mohammad Javad

    2017-01-01

    Introduction: This in vitro study compared the coronal microleakage of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement and Biodentine as intra-orifice barriers. Methods and Materials: The study was conducted on 76 extracted single-canal human teeth. Their root canals were prepared using ProTaper rotary files and filled with gutta percha and AH-26 sealer using lateral condensation technique. Coronal 3 mm of the gutta percha was removed from the root canals and replaced randomly with MTA, CEM cement or Biodentine in the three experimental groups (n=22). A positive and a negative control group were also included (n=5). The entire root surfaces of all teeth were covered with two layers of nail varnish in such a way that only the access openings were not coated. In the negative control group, the access opening was also coated with nail varnish. All teeth were immersed in India ink and after clearing, the samples were evaluated under a stereomicroscope under ×10 magnification to assess the degree of dye penetration. The data were analyzed using the Kruskal-Wallis test. The level of significance was set at 0.05. Results: The negative control group showed no leakage while the positive control group showed significantly higher microleakage than the test groups (P>0.05). CEM cement had the lowest (0.175±0.068 mm) and MTA showed the highest dye penetration (0.238±0.159 mm) among the experimental groups; although these differences were not statistically significant (P=0.313). Conclusion: CEM cement exhibited the least microleakage as an intra-orifice barrier in endodontically treated teeth. PMID:28512488

  20. Three-dimensional echocardiographic planimetry of maximal regurgitant orifice area in myxomatous mitral regurgitation: intraoperative comparison with proximal flow convergence

    Science.gov (United States)

    Breburda, C. S.; Griffin, B. P.; Pu, M.; Rodriguez, L.; Cosgrove, D. M. 3rd; Thomas, J. D.

    1998-01-01

    OBJECTIVES: We sought to validate direct planimetry of mitral regurgitant orifice area from three-dimensional echocardiographic reconstructions. BACKGROUND: Regurgitant orifice area (ROA) is an important measure of the severity of mitral regurgitation (MR) that up to now has been calculated from hemodynamic data rather than measured directly. We hypothesized that improved spatial resolution of the mitral valve (MV) with three-dimensional (3D) echo might allow accurate planimetry of ROA. METHODS: We reconstructed the MV using 3D echo with 3 degrees rotational acquisitions (TomTec) using a transesophageal (TEE) multiplane probe in 15 patients undergoing MV repair (age 59 +/- 11 years). One observer reconstructed the prolapsing mitral leaflet in a left atrial plane parallel to the ROA and planimetered the two-dimensional (2D) projection of the maximal ROA. A second observer, blinded to the results of the first, calculated maximal ROA using the proximal convergence method defined as maximal flow rate (2pi(r2)va, where r is the radius of a color alias contour with velocity va) divided by regurgitant peak velocity (obtained by continuous wave [CW] Doppler) and corrected as necessary for proximal flow constraint. RESULTS: Maximal ROA was 0.79 +/- 0.39 (mean +/- SD) cm2 by 3D and 0.86 +/- 0.42 cm2 by proximal convergence (p = NS). Maximal ROA by 3D echo (y) was highly correlated with the corresponding flow measurement (x) (y = 0.87x + 0.03, r = 0.95, p proximal convergence measurements.

  1. Placement of Endovascular Stent across the Branching Arteries: Long-term Serial Evaluation of Stent-tissue Responses Overlying the Arterial Orifices in an Experimental Study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Il; Chung, Jin Wook, E-mail: chungjw@snu.ac.kr [Seoul National University College of Medicine, Department of Radiology (Korea, Republic of); Kim, Hyun Beom [National Cancer Center of Korea, Department of Radiology and Center for Liver Cancer, Research Institute and Hospital (Korea, Republic of); Park, Jae Hyung [Seoul National University College of Medicine, Department of Radiology (Korea, Republic of); Seo, Jeong Wook [Seoul National University College of Medicine, Department of Pathology (Korea, Republic of); Kim, Hyo-Cheol; Jae, Hwan Jun; Lee, Whal [Seoul National University College of Medicine, Department of Radiology (Korea, Republic of)

    2012-10-15

    PurposeThis study was designed to investigate the effects of stenting across the branching arteries on the patency and stent-tissue responses over the branching arterial orifices. Methods: Thirteen dogs were observed after placing aortic stents across the celiac arteries (CA), superior mesenteric arteries (SMA), and renal arteries (RA). The animals were grouped according to stent types: large-cell group (n = 6) and small-cell group (n = 7). Angiography was performed to evaluate the branching artery patency at 2, 6, and 12 months after stent insertion, and the stent-tissue responses covering the orifices were evaluated on histopathologic examination. Results: All branching arteries were patent on follow-up angiography; however, three patterns of stent-tissue responses over the orifices were observed: neointimal layering, bridging septa, and papillary hyperplasia. Although neointimal layering and bridging septa were evenly observed, severe papillary hyperplasia was more frequent at SMA and CA than RA. Four RA showed less than 50% ostial patency, and localized infarct was observed in six kidneys (24%). The ostial patency tended to decrease with small-cell stent during the follow-up period. Conclusions: Various stent-tissue responses over the branching artery orifices are induced by the aortic stent covering the branching arteries and may not be easily detected by conventional angiography. Subclinical renal infarct also may occur despite patent renal angiography.

  2. Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full - Part 2: Orifice plates

    CERN Document Server

    International Organization for Standardization. Geneva

    2003-01-01

    ISO 5167-2:2003 specifies the geometry and method of use (installation and operating conditions) of orifice plates when they are inserted in a conduit running full to determine the flow-rate of the fluid flowing in the conduit. It also provides background information for calculating the flow-rate and is applicable in conjunction with the requirements given in ISO 5167-1. ISO 5167-2:2003 is applicable to primary devices having an orifice plate used with flange pressure tappings, or with corner pressure tappings, or with D and D/2 pressure tappings. Other pressure tappings such as vena contracta and pipe tappings have been used with orifice plates but are not covered by ISO 5167-2:2003. ISO 5167-2:2003 is applicable only to a flow which remains subsonic throughout the measuring section and where the fluid can be considered as single phase. It is not applicable to the measurement of pulsating flow. It does not cover the use of orifice plates in pipe sizes less than 50 mm or more than 1 000 mm, or for pipe Reynol...

  3. 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

  4. Sequential Venous Percutaneous Transluminal Angioplasty and Balloon Dilatation of the Interatrial Septum during Percutaneous Edge-to-Edge Mitral Valve Repair

    Directory of Open Access Journals (Sweden)

    Rezo Jorbenadze

    2017-01-01

    Full Text Available Percutaneous edge-to-edge mitral valve repair (PMVR is widely used for selected, high-risk patients with severe mitral valve regurgitation (MR. This report describes a case of 81-year-old woman presenting with severe and highly symptomatic mitral valve regurgitation (MR caused by a flail of the posterior mitral valve leaflet (PML. PMVR turned out to be challenging in this patient because of a stenosis and tortuosity of both iliac veins as well as sclerosis of the interatrial septum, precluding the vascular and left atrial access by standard methods, respectively. We managed to achieve atrial access by venous percutaneous transluminal angioplasty (PTA and balloon dilatation of the interatrial septum. Subsequently, we could advance the MitraClip® system to the left atrium, and deployment of the clip in the central segment of the mitral valve leaflets (A2/P2 resulted in a significant reduction of MR.

  5. Randomized, multicenter study comparing expanded polytetrafluoroethylene-covered endoprosthesis placement with percutaneous transluminal angioplasty in the treatment of superficial femoral artery occlusive disease.

    Science.gov (United States)

    Saxon, Richard R; Dake, Michael D; Volgelzang, Robert L; Katzen, Barry T; Becker, Gary J

    2008-06-01

    To compare the safety and effectiveness of the Viabahn endoprosthesis with that of percutaneous transluminal angioplasty (PTA) alone in the treatment of symptomatic peripheral arterial disease (PAD) affecting the superficial femoral artery (SFA). From 1998 to 1999, patients with symptomatic SFA PAD were enrolled in a prospective, multicenter randomized study and underwent either PTA alone (n = 100) or PTA followed by stent-graft placement (expanded polytetrafluoroethylene/nitinol self-expanding stent-graft) (n = 97) for stenoses or occlusions of the SFA that were 13 cm long or shorter. At baseline, there were no significant differences between the PTA and stent-graft treatment groups, including chronic limb ischemia status and treated lesion length. The stent-graft group had a significantly higher technical success rate (95% vs 66%, P late major adverse events. In this multicenter study, the patency, technical success, and clinical status results obtained with stent-grafts were superior to those obtained with PTA alone.

  6. The outcomes of initial endoscopic transluminal drainage are superior to percutaneous drainage for patients with infected pancreatic necrosis: a prospective cohort study.

    Science.gov (United States)

    He, Wen-Hua; Zhu, Yong; Zhu, Yin; Liu, Pi; Zeng, Hao; Xia, Liang; Yu, Chen; Chen, Hai-Ming; Shu, Xu; Liu, Zhi-Jian; Chen, You-Xiang; Lu, Nong-Hua

    2017-07-01

    The commonly used minimally invasive methods for patients with infected pancreatic necrosis (IPN) are initial endoscopic transluminal drainage (ETD) and percutaneous catheter drainage (PCD), which are followed, if necessary, by endoscopic or surgical necrosectomy. This study intends to explore which of the two minimally invasive treatments leads to a better prognosis. Patients with IPN and an indication for intervention were prospectively enrolled and underwent either initial ETD or PCD followed, if necessary, by endoscopic or surgical necrosectomy. Initial treatment success occurred in 8 of 11 patients after ETD (72.7%) and in 3 of 13 patients after PCD (30.8%) (risk ratio [RR] with ETD, 2.36; 95% CI 0.97-5.77; P = 0.04). After 1 year of follow-up, 72.7% of patients survived with ETD, and 69.2% survived with PCD (RR 1.05; 95% CI 0.63-1.75; P = 0.85). Intestinal fistula seems to have occurred less in the patients who received initial ETD rather than PCD therapy (9.1 vs. 38.5%; RR 0.24; 95% CI 0.03-1.73; P = 0.098). Fewer patients who underwent an initial ETD were transferred to surgery (9.1 vs. 46.2%; RR 0.20; 95% CI 0.03-1.40; P = 0.047). A higher rate of new-onset diabetes (3 cases) or impaired glucose tolerance (1 case) occurred in initial PCD compared to ETD (40 vs. 0%, P = 0.042). The outcomes of initial endoscopic transluminal drainage are superior to percutaneous drainage for patients with infected pancreatic necrosis (ChiCTR-ONRC-13003653).

  7. Risk of contrast induced nephropathy in diabetic patients affected by critical limb ischemia and diabetic foot ulcers treated by percutaneous transluminal angioplasty of lower limbs.

    Science.gov (United States)

    Meloni, Marco; Giurato, Laura; Izzo, Valentina; Stefanini, Matteo; Gandini, Roberto; Uccioli, Luigi

    2017-03-01

    The aim of this study is to evaluate the risk of contrast induced nephropathy (CIN) in diabetic patients with critical limb ischemia (CLI) and foot ulcers (FUs) treated by percutaneous transluminal angioplasty of lower limbs. The study group was composed of 145 diabetic patients who underwent a limb salvage protocol because of CLI and FUs between 2012 and 2015. All patients received a prophylactic strategy against the administration of contrast medium. Serum creatinine (SCr) levels were evaluated the day of procedure and for 3 days after. CIN was considered in case of increase of 25% of SCr in comparison to baseline value or an absolute increase of at least 0.5 mg/dl without other interfering factors. CIN occurred in 9% (14/145) of the cases. In the 1-year follow-up SCr returned to baseline values in 10 patients (71 %), 3 patients died (21%), and 1 patient had a major cardiovascular event (7%). No patients required dialysis. The risk was independent of chronic kidney disease stage. The rate of contrast nephropathy in each stage (X = 0.27) was as follows: 3/20 (15%) in stage 2; 3/66 (4.6%) in stage 3, 7/51 (13.7%) in stage 4; and 1/8 (12.5%) in stage 5. At the univariate analysis factors predicting this risk were anemia (HR 95% 2.5 [CI 1.8-4.2] P = .039) and heart failure (HR 95% 2.6 [CI 2.1-4.6] P = .038), while any significant variable was found at multivariate analysis. Peripheral percutaneous transluminal angioplasty in diabetic patients with CLI and FUs can be performed with a good safety factor and a low risk of contrast medium toxicity. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Per-oral endoscopic myotomy for achalasia: An American perspective

    OpenAIRE

    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 t...

  9. 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.

  10. Acquisition and correlation of cryogenic nitrogen mass flow data through a multiple orifice Joule-Thomson device

    Science.gov (United States)

    Papell, S. Stephen; Saiyed, Naseem H.; Nyland, Ted W.

    1990-05-01

    Liquid nitrogen mass flow rate, pressure drop, and temperature drop data were obtained for a series of multiple orifice Joule-Thomson devices, known as Visco Jets, over a wide range of flow resistance. The test rig used to acquire the data was designed to minimize heat transfer so that fluid expansion through the Visco Jets would be isenthalpic. The data include a range of fluid inlet pressures from 30 to 60 psia, fluid inlet temperatures from 118 to 164 R, outlet pressures from 2.8 to 55.8 psia, outlet temperatures from 117 to 162 R and flow rate from 0.04 to 4.0 lbm/hr of nitrogen. A flow rate equation supplied by the manufacturer was found to accurately predict single-phase (noncavitating) liquid nitrogen flow through the Visco Jets. For cavitating flow, the manufacturer's equation was found to be inaccurate. Greatly improved results were achieved with a modified version of the single-phase equation. The modification consists of a multiplication factor to the manufacturer's equation equal to one minus the downstream quality on an isenthalpic expansion of the fluid across the Visco Jet. For a range of flow resistances represented by Visco Jet Lohm ratings between 17,600 and 80,000, 100 percent of the single-phase data and 85 percent of the two-phase data fall within + or - 10 percent of predicted values.

  11. 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.

  12. 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

  13. Dependency of single-phase FAC of carbon and low-alloy steels for NPP system piping on pH, orifice distance and material

    International Nuclear Information System (INIS)

    Moon, Jeong Ho; Chung, Hung Ho; Sung, Ki Woung; Kim, Uh Chul; Rho, Jae Seong

    2005-01-01

    To investigate the Flow-Accelerated Corrosion (FAC) dependency of carbon steel (A106 Gr. B) and low-alloy steels (1Cr-1/2Mo, 2 1/4Cr-1Mo) on pH, orifice distance, and material, experiments were carried out. These experiments were performed using a flow velocity of 4 m/sec (partly 9 m/sec) at pH 8.0∼10.0 in an oxygen-free aqueous solution re-circulated in an Erosion-Corrosion Test Loop at 130 .deg. ... for 500 hours. The weight loss of the carbon steel specimens appeared to be positively dependent on the flow velocity. That of the carbon and low-alloy steel specimens also showed to be distinguishably dependent on the pH. At pH levels of 8.0∼9.5 it decreased, but increased from 9.5 to 10.0. Utility water chemistry personnel should carefully consider this kind of pH dependency to control the water system pH to mitigate FAC of the piping system material. The weight loss of the specimens located further from the orifice in the distance range of 6.8∼27.2 mm was shown to be greater, except for 2 1/4Cr-1Mo, which showed no orifice distance dependency. Low alloy steel specimens exhibited a factor of two times better resistance to FAC than that of the carbon steel. Based on this kind of FAC dependency of the carbon and low-alloy steels on the orifice distance and material, we conclude that it is necessary to alternate the composition of the secondary piping system material of NPPs, using low-alloy steels, such as 2 1/4Cr-1Mo, particularly when the system piping has to be replaced

  14. The exposure of radiologists and patients to radiation during coronary angiography and percutaneous transluminal coronary angioplasty (PTCA). The performance of cine x-ray equipment and film processing; Saeteilyaltistus sydaenangiografiatutkimuksissa ja kineangiografialaitteiden toimintakunto

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. 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

  16. 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).

  17. 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.

  18. In vitro measurement of stenotic human aortic valve orifice area in a pulsatile flow model. Validation of the continuity equation.

    Science.gov (United States)

    Perakis, A C; Montarello, J K; Rosenthal, E; Boyd, E G; Yates, A K; Deverall, P B; Curry, P V; Sowton, E

    1990-06-01

    Aortic valve orifice area estimation in patients with aortic stenosis may be obtained non-invasively using several Doppler echocardiographic methods. Their validity has been established by correlation with catheterization data using the Gorlin formula, with its inherent limitations, and small discrepancies between the methods are present. To evaluate these differences further, 15 patients with severe aortic stenosis (mean transvalvular gradient 70, range 40-130 mmHg) had aortic valve area estimations by Doppler echocardiography using two variations of the continuity equation. The intact valves removed at valve replacement surgery were then mounted in a pulsatile model and the anatomical area was measured (mean 0.67 +/- 0.17 cm-2) from video recordings during flow at 5.4 l min-1. Aortic valve area calculated using the integrals of the velocity-time curves measured at the left ventricular outflow tract and aortic jet (mean 0.65 +/- 0.17 cm2) correlated best with the anatomical area (r = 0.87, P less than 0.001). The area derived by using the ratio of maximum velocities from the left ventricular outflow tract and aortic jet (mean 0.69 +/- 0.18 cm2) also correlated well with the anatomical area (r = 0.79, P less than 0.001). The index between the left ventricular outflow tract and aortic jet maximum velocities was less than or equal to 0.25 in all. In patients with severe aortic stenosis the aortic valve area can be reliably estimated using Doppler echocardiography.

  19. Revascularização do miocárdio sem circulação extracorpórea com derivação intraluminal temporária (DILT na emergência pós angioplastia transluminal coronária (ATC Myocardial revascularization without cardiopulmonary bypass with temporary intraluminal shunt: emergential approach after transluminal coronary angioplasty

    Directory of Open Access Journals (Sweden)

    Ana M. Rocha Pinto

    1996-09-01

    Full Text Available No período de novembro 1989 a dezembro 1995, 18 doentes foram submetidos a cirurgia de emergência para revascularização do miocárdio sem circulação extracorpórea (CEC, devido a insucesso de angioplastia transluminal percutânea (ATC. Todos os pacientes apresentavam lesões do ramo interventricular anterior (RIA, coronária direita (CD ou coronária diagonal (Dg, passíveis de abordagem sem CEC. Em todos utilizamos derivação intraluminal temporária (DITL para manter o fluxo coronariano e minimizar a isquemia. Três (16,66% doentes foram operados na vigência de infarto agudo do miocárdio e 4 (22,22% doentes com importante corrente de lesão ao ECG. O choque cardiogênico estava presente em 3 (16,66% doentes. Não houve mortalidade. Realizamos estudo estatístico para comparação da mortalidade referida por diversos autores utilizando revascularização com CEC.From November 1989 through December 1995, eighteen patients underwent emergency coronary artery bypass grafting without cardiopulmonary bypass following percutaneous transluminal coronary angioplasty (PTCA. All patients had lesions in the left anterior descending coronary artery, diagonal coronary artery or right coronary artery, when we could reach without using cardiopulmonary bypass. In all cases we used a temporary intraluminal shunt in order to allow perfusion through the coronary artery and prevent ischemic effects. Three (16.66% patients had myocardial infarction before going to emergency surgery and 4 (22.22% patients had important ST segment elevation. The cardiogenic shock was present in 3 (16.66% patients. The in-hospital mortality was zero. We compared the several authors mortality rates and ours by a statistic analysis.

  20. Infrapopliteal Percutan Transluminal Angioplasty of Patients with TASC D Group Diabetic Foot Lesions According to the Transatlantic Inter-Society Consensus II

    Directory of Open Access Journals (Sweden)

    Mehmet Burak Çildağ

    2017-06-01

    Full Text Available Aim: We aimed to evaluate the effectiveness of percutaneous transluminal angioplasty (PTA in limb salvage in patients with diabetic foot disease and critical limb ischemia according to the Trans-Atlantic Inter-Society Consensus II (TASC classification system for type TASC D infrapopliteal artery disease. Methods: We retrospectively reviewed the angiographic records of patients with diabetic food disease and critical limb ischemia who underwent PTA between January 2014 and December 2015. Patients with TASC D isolated infrapopliteal artery disease and followed up for 12 months were included in the study. Technical success and limb salvage rates at 12 months were evaluated. Results: During the study period, 72 patients were screened for study enrolment and 32 met the inclusion criteria. The overall initial technical success rate in PTA was 68.8%. Limb salvage rate was 72.7% at 12 months in patients who had technical success. Among the factors that affected initial technical success and limb salvage at 12 months, only length of occlusion was found to be significant. Conclusion: PTA shows an effective technical success and good limb salvage rates in di¬abetic patients with TASC D group of critical limb ischemia. PTA may be attempted as an alternative treatment in patients with critical limb ischemia rated unfit for surgery.

  1. Transluminal attenuation gradient in coronary computed tomography angiography for determining stenosis severity of calcified coronary artery: a primary study with dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Minwen; Wei, Mengqi; Wen, Didi; Zhao, Hongliang; Liu, Ying; Li, Jian [Fourth Military Medical University, Department of Radiology, Xijing Hospital, Xi' an, Shaanxi Province (China); Li, Jiayi [Fourth Military Medical University, Department of Cardiology, Xijing Hospital, Xi' an, Shaanxi Province (China)

    2015-05-01

    To evaluate the diagnostic accuracy of transluminal attenuation gradient (TAG) for stenosis severity of calcified lesions assessed by coronary computed tomography angiography (CCTA). One hundred seven patients who underwent CCTA and coronary angiography (CAG) were enrolled. TAGs of 309 major epicardial coronary arteries were measured. The impact of plaque composition, Agatston scores, and lesion length ratio on TAG were analyzed. Diagnostic performance vs. CAG of TAG, CCTA, and combined TAG/CCTA were evaluated, and incremental value of TAG for reclassification of CCTA stenosis severity in calcified lesions was also analyzed. TAG decreased consistently with stenosis severity. TAG was significantly lower in coronary arteries with calcification scores >300 and lesion length ratios >2/3. TAG improved diagnostic accuracy of CCTA (c-statistic =0.982 vs. 0.942, P = 0.0001) in calcified lesions, and the sensitivity, specificity, positive, and negative predictive values of TAG cutoff ≤ -11.33 were 72 %, 91 %, 88 %, and 78 %, respectively. The addition of TAG to CCTA resulted in significant reclassification (NRI =0.093, P = 0.022) in calcified vessels. Measurement of TAG may improve diagnostic performance and reclassification of CCTA in coronary stenosis caused by calcified lesions. (orig.)

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

    Science.gov (United States)

    Dubský, Michal; Jirkovská, Alexandra; Bem, Robert; Fejfarová, Vladimíra; Pagacová, Libuse; Nemcová, Andrea; Sixta, Bedrich; Chlupac, Jaroslav; Peregrin, Jan H; Syková, Eva; Jude, Edward B

    2014-12-01

    The aim of our study was to compare the effect of autologous stem cell therapy (SCT) and percutaneous transluminal angioplasty (PTA) on diabetic foot disease (DFD) in patients with critical limb ischemia (CLI). Thirty-one patients with DFD and CLI treated by autologous stem cells and 30 patients treated by PTA were included in the study; 23 patients with the same inclusion criteria who could not undergo PTA or SCT formed the control group. Amputation-free survival, transcutaneous oxygen pressure (TcPO2) and wound healing were assessed over 12 months. Amputation-free survival after 6 and 12 months was significantly greater in the SCT and PTA groups compared with controls (P = 0.001 and P = 0.0029, respectively) without significant differences between the active treatment groups. Increase in TcPO2 did not differ between SCT and PTA groups until 12 months (both Ps diabetic foot and an observable effect of SCT on wound healing. Our results support SCT as a potential promising treatment in patients with CLI and diabetic foot. Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  3. C-reactive protein as an outcome predictor for percutaneous transluminal angioplasty in diabetic patients with peripheral arterial disease and infected foot ulcers.

    Science.gov (United States)

    Lin, Cheng-Wei; Hsu, Lung-An; Chen, Chun-Chi; Yeh, Jiun-Ting; Sun, Jui-Hung; Lin, Chia-Hung; Chen, Szu-Tah; Hsu, Brend Ray-Sea; Huang, Yu-Yao

    2010-11-01

    Although percutaneous transluminal angioplasty (PTA) is an effective therapeutic procedure for critical limb ischemia, several clinical factors can influence the outcome of PTA for peripheral arterial disease (PAD). The aim of this study is to identify the outcome predictors of PTA in infected diabetic foot patients with PAD. Eighty-five diabetic patients with a total of 90 infected limbs treated by PTA participated in this study. Patients were initially admitted for infected foot ulcers and were later diagnosed with PAD. Even though all patients underwent successful PTA within 15 days of admission, limb salvage was successful in 66 cases while 24 underwent subsequent amputation. The clinical characteristics and laboratory variables of both groups before PTA were compared and analyzed. Significantly higher level of C-reactive protein (CRP) was observed in the major amputation group before PTA. The cutoff value via receiver operating characteristic curve was 50mg/L (81.8% specificity, 70.7% sensitivity). Multivariate logistic regression analysis revealed that CRP levels may serve as valuable marker in determining a successful outcome. Reduced CRP levels (diabetic patients with infected foot ulcers. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  4. Medical operating personnel exposition levels during intracoronary irradiation using a Re188 full filled balloon catheter after percutaneous transluminal coronary artery

    Energy Technology Data Exchange (ETDEWEB)

    Ponce V, F.; Peix G, A.; Llerena R, L.; Santana V, L. [Instituto de Cardiologia, La Habana (Cuba); Lopez D, A. [Hospital Hermanos Amejeiras, La Habana (Cuba)

    2006-07-01

    The intracoronary irradiation using a full filled conventional balloon catheter with Rhenium 188 (Re188) after Percutaneous Transluminal Coronary Artery (PTCA) is a new relative treatment technique to reduce restenosis where the medical operating personnel are exposed to additional radiation ionizing level in the cath lab. In this study a radiation exposure level to medical operating personnel in the cath lab were measured with a Geiger Muller detector in 7 place to different distance from patient (to chest and abdominal region) catheter tabletop during a randomized clinical trial carried out in 25 patients whose were treated. The average concentrated Re188 activity used and treatment time were 5256{+-}2371 MBq/ml in 1.5-2 ml and 466{+-}195 seconds. At 3 cm from right arm patient the average maximum exposition rate were 0,63 mSv/h and 0,51 mSv h, to chest and abdominal patient level, respectively, where also average exposed dose per treated patient was 0,06 mSv and 0,05 mSv, respectively. Our results show that intracoronary irradiation with Re188 in the cath lab do not increase significatively the exposure radiation level to medical operating staff during treatment procedure and it is safe according national and international radiation protection regulations. (Author)

  5. Non-invasive imaging of myocardial bridge by coronary computed tomography angiography: the value of transluminal attenuation gradient to predict significant dynamic compression

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  6. Denervation of pulmonary trunk and pulmonary orifice in patients with surgically corrected mitral valve disease against high pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    N. A. Trofimov

    2017-01-01

    Full Text Available Aim: To study efficacy and safety of denervation of the trunk and pulmonary arteries (PADN procedure in patients with surgical correction of the mitral valve against a high degree of pulmonary hypertension compared to those of the isolated correction of mitral valve disease.Materials and methods: Placement of a mechanical mitral valve prosthesis and radiofrequency ablation Maze IV with Atri Cure ablator was performed in 39 patients with a mitral valve disease and high pulmonary hypertension (> 40 mm Hg and atrial fibrillation. From those, 8 patients (main group had additional circular denervation of the ganglionic plexus of the pulmonary trunk and orifice (PADN with a radiofrequency bipolar Atri Cure ablator under the control of transmurality.Results: All patients who had underwent surgery showed positive changes of the echocardiographic parameters, such as a decrease in the heart cavities sizes, degree of pulmonary hypertension, and an improvement in the systolic function of the left ventricle. There were no deaths, as well as specific complications related to the PADN procedure. In the main group of patients (n = 8, pulmonary hypertension decreased from 56.3 ± 5.4 mm Hg to 23.4 ± 2.7 mm Hg at day 1, to 24.3 ± 3.1 mm Hg at day 7, and to 23.7 ± 3.8 mm Hg at 1 month after the PADN procedure. At day 1, the target levels of pulmonary hypertension were achieved in 87.5% (7/8 of patients in the main study group and in 25.8% (8/31 of patients in the control group (p = 0.001. At day 7, the corresponding values were 75% (6/8 and 32.3% (10/31, respectively. Better results in the main study group were observed throughout the whole follow-up period (up to 2 months.Conclusion: The circular PADN procedure using a radio frequency bipolar ablator under the control of transmurality is an effective and safe method to correct a high-degree pulmonary hypertension. Further studies on the effectiveness of this procedure in

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. Increased Plasma Cathepsin S at the Time of Percutaneous Transluminal Angioplasty is Associated with 6-Months’ Restenosis of the Femoropopliteal Artery

    Directory of Open Access Journals (Sweden)

    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.

  12. Traços psicológicos dos pacientes submetidos a angioplastia transluminal coronária Psychological profile of patients that underwent coronary angioplasty

    Directory of Open Access Journals (Sweden)

    Lourdes Helena de Campos

    1990-12-01

    Full Text Available Este trabalho teve por objetivo a identificação de traços psicológicos e características emocionais comuns aos pacientes que foram, pela primeira vez, submetidos a angioplastia transluminal coronária (ATC, no Instituto Dante Pazzanese de Cardiologia. Foram analisados 84 pacientes, de ambros os sexos, com idade média de 55 anos. Foram realizadas, pela equipe de psicólogos, duas entrevistas semidirigidas, durante cada uma das quais foram aplicados o Inventário de Ansiedade Traço - Estado (IDATE e a Escala de Hamilton. Essas entrevistas foram realizadas imediatamente anterior à ATC e um dia após o procedimento, na alta dos pacientes. Os resultados permitiram-nos concluir que a grande maioria apresentou padrão comportamental tipo A, próprio do coronariano, alto estresse constitucional e ambiental e ansiedade - traço acima da média. Obtiveram alta porcentagem, também, as variáveis tensão, depressão, grau de competitividade e labilidade de humor.This paper presents psychological and emotional characteristics that were found common to patients that underwent a first coronary angioplasty at Instituto Dante Pazzanese de Cardiologia. We studied 84 patients of both sexes, with mean age of 55 years. Two semi-directed interviews were conducted by the psychology team, and during each of them the State-Trait - Anxiety Inventory STAI and the Hamilton Scale were applied. Such interviews were conducted immediately before PTCA and repeated one day after it, at patient's discharge. We concluded that most patients had a type A personality, typical of patients with coronary artey disease, high constitutional stress and anxiety-trace higher than the average population. There was also a high incidence of tension, depression, competitivity and humor lability.

  13. 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.

  14. Predicting Factors for Successful Maturation of Autogenous Haemodialysis Fistulas After Salvage Percutaneous Transluminal Angioplasty in Diabetic Nephropathy: A Study on Follow-Up Doppler Ultrasonography

    International Nuclear Information System (INIS)

    Jeon, Eui-Yong; Cho, Young Kwon; Cho, Sung Bum; Yoon, Dae Young; Suh, Seong O

    2016-01-01

    Maturation failure of autogenous arteriovenous fistula (aAVF) has been increasing after surgical procedures and the salvage percutaneous transluminal angioplasty (sPTA) for immature aAVF has been identified as an effective treatment modality. The aim of this study was to identify factors predicting successful aAVF maturation and to determine positive technical aspects of sPTA. We retrospectively reviewed medical records and radiological images of 59 patients who had undergone sPTA for non-maturing aAVFs. We analysed images from pre-surgical mapping Doppler ultrasonography, angiography, and angioplasty and follow-up Doppler ultrasonography performed within two weeks after sPTA. We assessed the following factors, for their ability to predict successful aAVF maturation: 1) patient factors (age; sex; co-morbidities; and aAVF age, side and type); 2) vessel factors (cephalic vein diameter and depth, presence of accessory veins, and pre- and postoperative radial artery disease); 3) lesion factors (stenosis number, location and severity); and 4) technical factors (presence of residual stenosis and anatomic success ratio (ASR) on follow-up Doppler ultrasonography). The technical and clinical success rates were both 94.9% (56/59); the mean ASR was 0.84. An ASR of ≥ 0.7 and no significant residual stenosis (< 30%) (both P < 0.001) on two-week follow-up Doppler ultrasonography predicted successful aAVF maturation. For more precise prediction of successful aAVF maturation after sPTA, short-term follow-up Doppler ultrasonography (< 2 weeks) was useful. If the ASR was < 0.7 or if residual stenosis was ≥ 30%, immediate repeat sPTA is recommended

  15. 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.

  16. 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...

  17. Cost-Effectiveness of Endovascular Femoropopliteal Intervention Using Drug-Coated Balloons Versus Standard Percutaneous Transluminal Angioplasty: Results From the IN.PACT SFA II Trial.

    Science.gov (United States)

    Salisbury, Adam C; Li, Haiyan; Vilain, Katherine R; Jaff, Michael R; Schneider, Peter A; Laird, John R; Cohen, David J

    2016-11-28

    The aim of this study was to evaluate the cost-effectiveness of drug-coated balloon (DCB) angioplasty versus standard percutaneous transluminal angioplasty (PTA). Recent trials have reported lower rates of target lesion revascularization with DCB angioplasty versus standard PTA. However, the cost-effectiveness of DCB angioplasty is unknown. A prospective economic study was performed alongside the IN.PACT SFA II (IN.PACT Admiral Drug-Coated Balloon vs. Standard Balloon Angioplasty for the Treatment of Superficial Femoral Artery [SFA] and Proximal Popliteal Artery [PPA]) trial, which randomized 181 patients with femoropopliteal disease to the IN.PACT DCB versus standard PTA. Resource use data were collected over 2-year follow-up, and costs were assigned using resource-based accounting and billing data. Health utilities were assessed using the EuroQol 5-dimensions questionnaire. Cost-effectiveness was assessed as cost per quality-adjusted life-year (QALY) gained using a decision-analytic model on the basis of empirical data from the trial assuming identical long-term mortality. Initial costs were $1,129 per patient higher with DCB angioplasty than standard PTA, driven by higher costs for the DCB itself. Between discharge and 24 months, target limb-related costs were $1,212 per patient lower with DCB angioplasty such that discounted 2-year costs were similar for the 2 groups ($11,277 vs. $11,359, p = 0.97), whereas QALYs tended to be greater among patients treated with DCBs (1.53 ± 0.44 vs. 1.47 ± 0.42, p = 0.40). The probability that DCB angioplasty is cost-effective compared with standard PTA was 70% using a threshold of $50,000 per QALY gained and 79% at a threshold of $150,000 per QALY gained. For patients with femoropopliteal disease, DCB angioplasty is associated with better 2-year outcomes and similar target limb-related costs compared with standard PTA. Formal cost-effectiveness analysis on the basis of these results suggests that use of the DCB angioplasty

  18. Cognitive functioning and subjective quality of life in relapsing-remitting multiple sclerosis patients before and after percutaneous transluminal angioplasty: a preliminary report

    Directory of Open Access Journals (Sweden)

    De Pasquale C

    2014-06-01

    Full Text Available Concetta De Pasquale,1,2 Maria Luisa Pistorio,1 Massimiliano Veroux,2 Alessia Giaquinta,2 Pierfrancesco Veroux,2 Michele Fornaro11Department of Education Science, University of Catania, Catania, Italy; 2Vascular Surgery and Organ Transplant Unit, Department of Surgery Transplantation and Advanced Technologies, University Hospital of Catania, Catania, ItalyBackground: Multiple sclerosis (MS is a disease of the nervous system that has profound effects on everyday functioning and quality of life of not only the person who is diagnosed, but also her/his family and acquaintances. Despite this, the uncertainties of the actual etiological basis of MS make it difficult to reach a conclusive statement about the optimal therapeutic management of the disease, which may differ depending on the given case and phase of illness. This has led to an interest in potential novel therapeutic avenues, including percutaneous transluminal angioplasty (PTA. Yet, evidence in support of PTA in the management of MS is scarce and contradictory. The aim of the present study was to provide a preliminary assessment as to whether PTA may impact subjective quality of life and cognitive functioning in severe MS. Method: Ninety-five MS outpatients were followed-up for 24 months on a scheduled basis using the Milan Overall Dementia Assessment and the short-form 36-item scales, and were clinically evaluated by an appointed neurologist and psychiatrist. Results: At end point (month 24, only a minority of patients were still active in the study (n=33 or 34.74%. Among other measures, those who remained in the study until completion showed a significantly better Expanded Disability Status Scale and Milan Overall Dementia Assessment autonomy profile at study entrance compared to those patients who did not remain in the study until completion. Limitations were: a lack of any active control group; small sample size; Berkson’s bias; and selection by indication biases.Conclusion: Given

  19. A new era of therapeutic strategies for chronic thromboembolic pulmonary hypertension by two different interventional therapies; pulmonary endarterectomy and percutaneous transluminal pulmonary angioplasty.

    Directory of Open Access Journals (Sweden)

    Takumi Inami

    Full Text Available BACKGROUND: Pulmonary endarterectomy (PEA is established for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH. Recently, percutaneous transluminal pulmonary angioplasty (PTPA has been added for peripheral-type CTEPH, whose lesions exist in segmental, subsegmental, and more distal pulmonary arteries. A shift in clinical practice of interventional therapies occurred in 2009 (first mainly PEA, later PTPA. We examined the latest clinical outcomes of patients with CTEPH. METHODS AND RESULTS: This study retrospectively included 136 patients with CTEPH. Twenty-nine were treated only with drug (Drug-group, and the other 107 underwent interventional therapies (Interventions-group (39 underwent PEA [PEA-group] and 68 underwent PTPA [PTPA-group]. Total 213 PTPA sessions (failures, 0%; mortality rate, 1.47% was performed in the PTPA-group (complications: reperfusion pulmonary edema, 7.0%; hemosputum or hemoptysis, 5.6%; vessel dissection, 2.3%; wiring perforation, 0.9%. Although baseline hemodynamic parameters were significantly more severe in the Interventions-group, the outcome after the diagnosis was much better in the Interventions-group than in the Drug-group (98% vs. 64% 5-year survival, p<0.0001. Hemodynamic improvement in the PEA-group was a 46% decrease in mean pulmonary arterial pressure (PAP and a 49% decrease in total pulmonary resistance (TPR (follow-up period; 74.7 ± 32.3 months, while those in the PTPA-group were a 40% decrease in mean PAP and a 49% decrease in TPR (follow-up period; 17.4 ± 9.3 months. The 2-year survival rate in the Drug-group was 82.0%, and the 2-year survival rate, occurrence of right heart failure, and re-vascularization rate in the PEA-group were 97.4%, 2.6%, and 2.8%, and those in the PTPA-group were 98.5%, 2.9%, and 2.9%, respectively. CONCLUSION: The patients who underwent interventional therapies had better results than those treated only with drugs. The availability of both of these operative

  20. [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

  1. Natural gas; Gas Natural

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos A.; Moraes, Claudia C.D. [Eletricidade de Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil); Fonseca, Carlos H.F. [Centrais Eletricas de Santa Catarina S.A., Florianopolis, SC (Brazil); Silva, Clecio Fabricio da; Alves, Ricardo P. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Sposito, Edivaldo Soares; Hulle, Lutero [Espirito Santo Centrais Eletricas S.A. (ESCELSA), Vitoria, ES (Brazil); S. Martins, Icaro da [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil); Vilhena, Joao Luiz S. de [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Fagundes, Zaluar Aquino [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1996-12-31

    An increase in the consumption of natural gas in Brazil is an expected fact in what concerns energetic planning. This work presents the existing situation in what concerns natural gas utilization in the main world economies, as well as an analysis of the participation of this fuel among the energy final consumption per sources. The Brazilian consumption of natural gas is also analysed as well as the international agreement between Brazil and Bolivia for natural gas commercialization. Some legal, institutional and political aspects related to natural gas commercialization are also discussed. Finally, several benefits to be brought by the utilization of natural gas are presented 10 refs., 3 tabs.

  2. Global numerical model for the assessment of the effect of geometry and operation conditions on insert and orifice region plasmas of a thermionic hollow cathode electron source

    International Nuclear Information System (INIS)

    Korkmaz, O.; Celik, M.

    2014-01-01

    Thermionic hollow cathodes have been widely used in wide variety of areas such as spacecraft electric propulsion systems, material processing and lasers for more than half a century as efficient electron sources. Especially in electric propulsion systems, hollow cathodes are being used as electron sources for propellant ionization and ion beam neutralization. Moreover, it is also a promising candidate for utilization as a stand-alone propulsion system in microsatellites or nanosatellites due to its small physical size, low power consumption and ease of operation. On the other hand, the small geometry of the typical orificed hollow cathodes makes the plasma diagnostics difficult which is why numerical studies become important for understanding the driving physical processes behind their operation, and the effects of the geometry and the operation parameters on cathode performance. In this paper, a global numerical model for the insert and orifice plasma of a hollow cathode is presented where volume averaged plasma parameters are considered for both regions. The results of this study show that the developed model can be used for designing and sizing orificed hollow cathodes as comparisons with the results of experimental and other numerical studies are in good agreement with the ones obtained from the developed model. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Global numerical model for the assessment of the effect of geometry and operation conditions on insert and orifice region plasmas of a thermionic hollow cathode electron source

    Energy Technology Data Exchange (ETDEWEB)

    Korkmaz, O.; Celik, M. [Department of Mechanical Engineering, Bogazici University, Istanbul (Turkey)

    2014-11-15

    Thermionic hollow cathodes have been widely used in wide variety of areas such as spacecraft electric propulsion systems, material processing and lasers for more than half a century as efficient electron sources. Especially in electric propulsion systems, hollow cathodes are being used as electron sources for propellant ionization and ion beam neutralization. Moreover, it is also a promising candidate for utilization as a stand-alone propulsion system in microsatellites or nanosatellites due to its small physical size, low power consumption and ease of operation. On the other hand, the small geometry of the typical orificed hollow cathodes makes the plasma diagnostics difficult which is why numerical studies become important for understanding the driving physical processes behind their operation, and the effects of the geometry and the operation parameters on cathode performance. In this paper, a global numerical model for the insert and orifice plasma of a hollow cathode is presented where volume averaged plasma parameters are considered for both regions. The results of this study show that the developed model can be used for designing and sizing orificed hollow cathodes as comparisons with the results of experimental and other numerical studies are in good agreement with the ones obtained from the developed model. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. [Effect of modified huanglian wendan decoction in treating senile patients with mild cognitive impairment of turbid-phlegm blocking orifice syndrome].

    Science.gov (United States)

    Guo, Ren-zhen; Zhou, Wen-quan; Luo, Zeng-gang

    2010-01-01

    To observe the clinical efficacy of modified Huanglian Wendan Decoction (HWD) in treating senile mild cognitive impairment (MCI) of turbid-phlegm blocking orifice syndrome. With a block randomized, double-blinded and controlled design adopted, the 64 patients of MCI selected from December 2007 to February 2009 were randomly and equally assigned to two groups. The treatment group was treated with HWD in dose of 200 mL, twice a day; the control group was given Aniracetam 0.2 g (for patients over 70-years-old, 0.1 g) three times a day. And the illusive medicine in dosage-form of capsule/decoction simulated to that used in the opposite group was applied. The medication and observation lasted for three months. Chinese medicine syndrome, cognition capacity (by MMSE), laboratory indexes [acetylcholine (Ach), superoxide dismutase (SOD), malondialdehyde (MDA)] and safety related indexes in patients were observed. After treatment, MMSE score increased in both groups, but the increment in the treatment group was significantly higher than that in the control group (PAniracetam; and with effects for raising SOD activity and reducing MDA level similar to those of Aniracetam.

  5. Linearized Euler Equations for the Determination of Scattering Matrices for Orifice and Perforated Plate Configurations in the High Mach Number Regime

    Directory of Open Access Journals (Sweden)

    Moritz Schulze

    2016-10-01

    Full Text Available The interaction of a plane acoustic wave and a sheared flow is numerically investigated for simple orifice and perforated plate configurations in an isolated, non-resonant environment for Mach numbers up to choked conditions in the holes. Analytical derivations found in the literature are not valid in this regime due to restrictions to low Mach numbers and incompressible conditions. To allow for a systematic and detailed parameter study, a low-cost hybrid Computational Fluid Dynamic/Computational Aeroacoustic (CFD/CAA methodology is used. For the CFD simulations, a standard k–ϵ Reynolds-Averaged Navier–Stokes (RANS model is employed, while the CAA simulations are based on frequency space transformed linearized Euler equations (LEE, which are discretized in a stabilized Finite Element method. Simulation times in the order of seconds per frequency allow for a detailed parameter study. From the application of the Multi Microphone Method together with the two-source location procedure, acoustic scattering matrices are calculated and compared to experimental findings showing very good agreement. The scattering properties are presented in the form of scattering matrices for a frequency range of 500–1500 Hz.

  6. 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.

  7. Fused aortic valve without an elliptical-shaped systolic orifice in patients with severe aortic stenosis: cardiac computed tomography is useful for differentiation between bicuspid aortic valve with raphe and tricuspid aortic valve with commissural fusion

    Energy Technology Data Exchange (ETDEWEB)

    Bak, So Hyeon; Ko, Sung Min [Konkuk University School of Medicine, Departments of Radiology, Konkuk University Medical Center, Seoul (Korea, Republic of); Song, Meong Gun; Shin, Je Kyoun; Chee, Hyun Kun; Kim, Jun Suk [Konkuk University School of Medicine, Departments of Thoracic Surgery, Konkuk University Medical Center, Seoul (Korea, Republic of)

    2015-04-01

    The objective is to determine cardiac computed tomography (CCT) features capable of differentiating between bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) in severe aortic stenosis (AS) patients with fused cusp and without elliptical-shaped systolic orifices. We retrospectively enrolled 53 patients who had severe AS with fused cusps and without an elliptical-shaped systolic orifice on CCT and who had undergone surgery. CCT features were analyzed using: (1) aortic valve findings including cusp size, cusp area, opening shape, midline calcification, fusion length, calcium volume score, and calcium grade; (2) diameters of ascending and descending aorta, and main pulmonary artery; and (3) rheumatic mitral valve findings. The variables were evaluated using univariate and multivariate logistic regression analyses. At surgery, 19 patients had BAV and 34 had TAV. CCT features including uneven cusp size, uneven cusp area, round-shaped systolic orifice, longer cusp fusion, and dilatation of ascending aorta were significantly associated with BAV (P < 0.05). In particular, fusion length (OR, 1.76; P = 0.001), uneven cusp area (OR, 10.46; P = 0.012), and midline calcification (OR, 0.08; P = 0.013) were strongly associated with BAV. CCT provides diagnostic clues that helps differentiate between BAV with raphe and TAV with commissural fusion in patients with severe AS. (orig.)

  8. Hydraulic Robotic Surgical Tool Changing Manipulator.

    Science.gov (United States)

    Pourghodrat, Abolfazl; Nelson, Carl A; Oleynikov, Dmitry

    2017-03-01

    Natural orifice transluminal endoscopic surgery (NOTES) is a surgical technique to perform "scarless" abdominal operations. Robotic technology has been exploited to improve NOTES and circumvent its limitations. Lack of a multitasking platform is a major limitation. Manual tool exchange can be time consuming and may lead to complications such as bleeding. Previous multifunctional manipulator designs use electric motors. These designs are bulky, slow, and expensive. This paper presents design, prototyping, and testing of a hydraulic robotic tool changing manipulator. The manipulator is small, fast, low-cost, and capable of carrying four different types of laparoscopic instruments.

  9. Fast-track video-assisted thoracoscopic surgery

    DEFF Research Database (Denmark)

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

    2016-01-01

    -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...... articles. Using abstracts, areas of interest for developing a fast-track protocol were selected. Results The minimally invasive approach can be divided into several surgical methods that need further research to establish superiority. The role of intubation has to be further examined as well as the role...

  10. Anesthesia for Routine and Advanced Upper Gastrointestinal Endoscopic Procedures.

    Science.gov (United States)

    Sharp, Christopher D; Tayler, Ezekiel; Ginsberg, Gregory G

    2017-12-01

    This article aims to detail the breadth and depth of advanced upper gastrointestinal endoscopic procedures. It will focus on sedation and airway management concerns pertaining to this emerged and emerging class of minimally invasive interventions. The article will also cover endoscopic hemostasis, endoscopic resection, stenting and Barrett eradication therapy plus endoscopic ultrasound. It additionally will address the nuances of endoscopic retrograde cholangiopancreatography and new natural orifice transluminal endoscopic surgery procedures including endoscopic cystgastrostomy and the per-oral endoscopic myotomy procedure. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Design and Analysis of a Novel Articulated Drive Mechanism for Multifunctional NOTES Robot.

    Science.gov (United States)

    Shen, Tao; Nelson, Carl A; Warburton, Kevin; Oleynikov, Dmitry

    2015-02-01

    This paper presents a novel articulated drive mechanism (ADM) for a multifunctional natural orifice transluminal endoscopic surgery (NOTES) robotic manipulator. It consists mainly of three major components including a snakelike linkage, motor housing, and an arm connector. The ADM can articulate into complex shapes for improved access to surgical targets. A connector provides an efficient and convenient modularity for insertion and removal of the robot. Four DC motors guide eight cables to steer the robot. The workspace, cable displacement and force transmission relationships are derived. Experimental results give preliminary validation of the feasibility and capability of the ADM system.

  12. 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.

  13. 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

  14. 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.

  15. Efectividad clínica en el cuidado del orificio de salida del catéter peritoneal Clinical effectiveness in peritoneal catheter exit orifice care

    Directory of Open Access Journals (Sweden)

    Antonia Gil Gil

    2012-09-01

    methods followed by the professionals who provide peritoneal catheter exit orifice care. We found that all of them had a sound basis and showed effective results. However, we asked ourselves which of them would be the most suitable to use in our unit. We opted to use the recommendations of scientific literature, including variables such as the specific needs of each patient, according to the environmental conditions of our community and the seasons of the year. The main objective of our study was to assess the validity and effectiveness of the protocol we had established for our patients. We carried out a descriptive and longitudinal epidemiological study lasting 2 years and 8 months. We calculated the incidence rate of catheter exit orifice infections and peritonitis per patient and for each of the years of the study (2008-2009-2010. We assessed the result by comparing them with the normality indices set by the Spanish Nephrology Association, in 2007. We broke down the total of infections according to seasons and calculated the percentage. We differentiated between infections caused by gram + and gram-bacteria. The results obtained showed that our protocol is valid and suitable for our patients, obtaining an overall peritonitis incidence rate of 0.72 for every 24 patient-months and an exit orifice infection rate of 0.61 patient-years, both of which are lower than the standard established by the Spanish Nephrology Association (2007. A higher incidence of infections was found in the summer period, specifically 46%. 1% chlorhexidine covers gram+ bacteria, gram- bacteria, spores, viruses and fungi but was found to be most effective with gram+ microorganisms.

  16. 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.

  17. Design of a randomized controlled trial of comprehensive rehabilitation in patients with myocardial infarction, stabilized acute coronary syndrome, percutaneous transluminal coronary angioplasty or coronary artery bypass grafting: Akershus Comprehensive Cardiac Rehabilitation Trial (the CORE Study

    Directory of Open Access Journals (Sweden)

    Karin Kogstad Else

    2000-11-01

    Full Text Available Abstract Objectives 1. To assess the long-term effectiveness of a comprehensive cardiac rehabilitation programme on quality of life and survival in patients with a large spectrum of cardiovascular diseases (myocardial infarction, acute coronary syndrome, percutaneous transluminal coronary angioplasty and coronary artery bypass grafting. 2. To establish the degree of correlation between expected improvement of health-related quality of life and improvement in physical function attributable to rehabilitation in the intervention group, in comparison with similar changes in the conventional care group. Design Randomized, controlled, parallel-group design (intervention/conventional care. Setting Akershus County, southeast of Oslo City, Norway. Participants 500 patients, men and women, aged 40-85 years, who have sustained at least one of the above-mentioned cardiovascular diseases. Interventions 8 weeks of supervised, structured physical training of three periods of 20 min per week, targeting a heart rate of 60-70% of the individual's maximum; home-based physical exercise training with the same basic schedule as in the supervised period; quantification of patients' compliance with the exercise programme by the use of wristwatches, information stored in the watch memory being retrieved once a month during the 3-year follow-up period; and life-style modification with an emphasis on the cessation of smoking and on healthy nutrition and weight control.

  18. Utilizing flat-panel detector parenchymal blood volume imaging (FD-PBV) for quantitative kidney perfusion analysis during the process of percutaneous transluminal renal angioplasty (PTRA): A case report.

    Science.gov (United States)

    Qiu, Chenyang; Shao, Jiang; Liu, Xiu; Liu, Bao

    2017-11-01

    Traditional digital subtraction angiography (DSA) provides lumen morphology of renal artery as indicators for vascular patency in patients with renal artery stenosis (RAS). It, however, lacks hemodynamic information toward target kidney. To solve this shortcoming, a novel technique, flat-panel detector parenchymal blood volume imaging (FD-PBV), is introduced, which is able to evaluate hemodynamic changes of target kidney intraoperatively. A 77-year-old female presented with hypertension, intermittent dizziness, nausea, and fatigue. Ninety-nine percent stenosis of left RAS was found. Percutaneous transluminal renal angioplasty was performed, along with FD-PBV acquisition protocol. Her symptoms relieved gradually after procedure. Intuitive FD-PBV maps showed her renal perfusion improved remarkably. Quantitative analysis of FD-PBV showed her kidney volume was 47.02 and 75.61 cm with average density of contrast medium (CM) 58.1 HU and 311.5 HU before and after stenting. Follow-up at 6 months showed patency of the stent and stable kidney blood perfusion. FD-PBV technique possesses a remarkable value in quantitatively assessing the changes of kidney blood perfusion and can be a useful auxiliary technique for DSA. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

  19. Drug-Coated Balloon vs Standard Percutaneous Transluminal Angioplasty for the Treatment of Atherosclerotic Lesions in the Superficial Femoral and Proximal Popliteal Arteries: One-Year Results of the MDT-2113 SFA Japan Randomized Trial.

    Science.gov (United States)

    Iida, Osamu; Soga, Yoshimitsu; Urasawa, Kazushi; Saito, Shigeru; Jaff, Michael R; Wang, Hong; Ookubo, Hiroko; Yokoi, Hiroyoshi

    2018-02-01

    To assess the safety and effectiveness of the MDT-2113 (IN.PACT Admiral) drug-coated balloon (DCB) for the treatment of de novo and native artery restenotic lesions in the superficial femoral and proximal popliteal arteries vs percutaneous transluminal angioplasty (PTA) with an uncoated balloon in a Japanese cohort. MDT-2113 SFA Japan ( ClinicalTrials.gov identifier NCT01947478) is an independently adjudicated, prospective, randomized, single-blinded trial that randomized (2:1) 100 patients (mean age 73.6±7.0 years; 76 men) from 11 Japanese centers to treatment with DCB (n=68) or PTA (n=32). Baseline characteristics were similar between the groups, including mean lesion length (9.15±5.85 and 8.89±6.01 cm for the DCB and PTA groups, respectively). The primary effectiveness outcome was primary patency at 12 months, defined as freedom from clinically-driven target lesion revascularization (CD-TLR) and freedom from restenosis as determined by duplex ultrasonography. The safety endpoint was a composite of 30-day device- and procedure-related death and target limb major amputation and clinically-driven target vessel revascularization within 12 months. Patients treated with DCBs exhibited superior 12-month primary patency (89%) compared to patients treated with PTA (48%, pSFA Japan trial showed superior treatment effect for DCB vs PTA, with excellent patency and low CD-TLR rates. These results are consistent with other IN.PACT SFA DCB trials and demonstrate the safety and effectiveness of this DCB for the treatment of femoropopliteal lesions in this Japanese cohort.

  20. Drug-coated balloon versus standard percutaneous transluminal angioplasty for the treatment of superficial femoral and popliteal peripheral artery disease: 12-month results from the IN.PACT SFA randomized trial.

    Science.gov (United States)

    Tepe, Gunnar; Laird, John; Schneider, Peter; Brodmann, Marianne; Krishnan, Prakash; Micari, Antonio; Metzger, Christopher; Scheinert, Dierk; Zeller, Thomas; Cohen, David J; Snead, David B; Alexander, Beaux; Landini, Mario; Jaff, Michael R

    2015-02-03

    Drug-coated balloons (DCBs) have shown promise in improving the outcomes for patients with peripheral artery disease. We compared a paclitaxel-coated balloon with percutaneous transluminal angioplasty (PTA) for the treatment of symptomatic superficial femoral and popliteal artery disease. The IN.PACT SFA Trial is a prospective, multicenter, single-blinded, randomized trial in which 331 patients with intermittent claudication or ischemic rest pain attributable to superficial femoral and popliteal peripheral artery disease were randomly assigned in a 2:1 ratio to treatment with DCB or PTA. The primary efficacy end point was primary patency, defined as freedom from restenosis or clinically driven target lesion revascularization at 12 months. Baseline characteristics were similar between the 2 groups. Mean lesion length and the percentage of total occlusions for the DCB and PTA arms were 8.94 ± 4.89 and 8.81 ± 5.12 cm (P=0.82) and 25.8% and 19.5% (P=0.22), respectively. DCB resulted in higher primary patency versus PTA (82.2% versus 52.4%; P<0.001). The rate of clinically driven target lesion revascularization was 2.4% in the DCB arm in comparison with 20.6% in the PTA arm (P<0.001). There was a low rate of vessel thrombosis in both arms (1.4% after DCB and 3.7% after PTA [P=0.10]). There were no device- or procedure-related deaths and no major amputations. In this prospective, multicenter, randomized trial, DCB was superior to PTA and had a favorable safety profile for the treatment of patients with symptomatic femoropopliteal peripheral artery disease. http://www.clinicaltrials.gov. Unique Identifiers: NCT01175850 and NCT01566461. © 2014 The Authors.

  1. PLURALIZING NATURE

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    not necessary mean planning for a one common nature. As exemplified by the River Aire Re-naturalization Project (2002-2015), landscape architecture might provide an alternative approach to nature restoration that is more site specific and allows for multiple interpretations to coexist. In the presentation...

  2. 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

  3. Low-Dose Paclitaxel-Coated Versus Uncoated Percutaneous Transluminal Balloon Angioplasty for Femoropopliteal Peripheral Artery Disease: One-Year Results of the ILLUMENATE European Randomized Clinical Trial (Randomized Trial of a Novel Paclitaxel-Coated Percutaneous Angioplasty Balloon).

    Science.gov (United States)

    Schroeder, Henrik; Werner, Martin; Meyer, Dirk-Roelfs; Reimer, Peter; Krüger, Karsten; Jaff, Michael R; Brodmann, Marianne

    2017-06-06

    Numerous studies have reported favorable outcomes using drug-coated balloons (DCBs) for treatment of symptomatic peripheral artery disease of the superficial femoral and popliteal arteries. However, the treatment effect compared with an uncoated balloon has differed greatly among the randomized trials, with better outcomes observed with higher-dose DCBs. This European trial was designed to assess the safety and effectiveness of a next-generation low-dose (2-µg/mm 2 surface dose of paclitaxel) DCB. This was a prospective, randomized, multicenter, single-blinded trial. Patients were randomized (3:1) to treatment with a low-dose DCB or an uncoated percutaneous transluminal angioplasty (PTA) balloon. The primary safety end point was a composite of freedom from device- and procedure-related death through 30 days after the procedure and freedom from target limb major amputation and clinically driven target lesion revascularization through 12 months after the procedure. The primary effectiveness end point was primary patency at 12 months. Patients were randomized to treatment with a DCB (222 patients, 254 lesions) or uncoated PTA balloon (72 patients, 79 lesions) after successful predilatation. Mean lesion length was 7.2 and 7.1 cm, and 19.2% and 19.0% of lesions represented total occlusions, respectively. The primary safety end point was met, and superiority was demonstrated; freedom from a primary safety event was 94.1% (193 of 205) with DCB and 83.3% (50 of 60) with PTA, for a difference of 10.8% (95% confidence interval, 0.9%-23.0%). The primary effectiveness end point was met, and superiority of DCB over PTA was achieved (83.9% [188 of 224] versus 60.6% [40 of 66]; P <0.001). Outcomes with DCB were also superior to PTA per the Kaplan-Meier estimate for primary patency (89.0% versus 65.0% at 365 days; log-rank P <0.001) and for rates of clinically driven target lesion revascularization (5.9% versus 16.7%; P =0.014). Superiority with a low-dose DCB for femoropopliteal

  4. The second law analysis of natural gas behavior within a vortex tube

    Directory of Open Access Journals (Sweden)

    Kargaran Mahyar

    2013-01-01

    Full Text Available Vortex tube is a simple device without a moving part which is capable of separating hot and cold gas streams from a higher pressure inlet gas stream. The mechanism of energy separation has been investigated by several scientists and second law approach has emerged as an important tool for optimizing the vortex tube performance. Here, a thermodynamic model has been used to investigate vortex tube energy separation. Further, a method has been proposed for optimizing the vortex tube based on the rate of entropy generation obtained from experiments. Also, an experimental study has been carried out to investigate the effects of the hot tube length and cold orifice diameter on entropy generation within a vortex tube with natural gas as working fluid. A comparison has been made between air and natural gas as working fluids. The results show that the longest tube generates lowest entropy for NG. For air, it is middle tube which generates lowest entropy. Integration of entropy generation for all available cold mass fractions unveiled that an optimized value for hot tube length and cold orifice diameter is exist.

  5. PLURALIZING NATURE

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    Denmark is widely recognised for its democratic approach to planning and the idea of planning for the common good. This interest in the common good and common values seems also to be reflected in the way which nature restoration is planned and managed – one common nature directed by the public...... authorities. But nature restoration is far from being a neural undertaking. Just like any other type of heritage production it can be the source of dissonance – ‘our’ nature is not necessary ‘their’ nature. Often this dissonance is managed in ways, which are not particular sensitive to site......-specificity. As exemplified by the Skjern River Restoration Project (1999-2003), one interpretation of the landscape sometimes suppresses other valid interpretations neglecting its diverse history. However, evidence from Switzerland suggests that planning for the common good, in the case of nature restoration, does...

  6. Temporal naturalism

    Science.gov (United States)

    Smolin, Lee

    2015-11-01

    Two people may claim both to be naturalists, but have divergent conceptions of basic elements of the natural world which lead them to mean different things when they talk about laws of nature, or states, or the role of mathematics in physics. These disagreements do not much affect the ordinary practice of science which is about small subsystems of the universe, described or explained against a background, idealized to be fixed. But these issues become crucial when we consider including the whole universe within our system, for then there is no fixed background to reference observables to. I argue here that the key issue responsible for divergent versions of naturalism and divergent approaches to cosmology is the conception of time. One version, which I call temporal naturalism, holds that time, in the sense of the succession of present moments, is real, and that laws of nature evolve in that time. This is contrasted with timeless naturalism, which holds that laws are immutable and the present moment and its passage are illusions. I argue that temporal naturalism is empirically more adequate than the alternatives, because it offers testable explanations for puzzles its rivals cannot address, and is likely a better basis for solving major puzzles that presently face cosmology and physics. This essay also addresses the problem of qualia and experience within naturalism and argues that only temporal naturalism can make a place for qualia as intrinsic qualities of matter.

  7. Natural Philosophy

    OpenAIRE

    Blair, Ann M.

    2006-01-01

    Natural philosophy” is often used by European historians as an umbrella term to designate the study of nature before it can easily be identified with what we call “science” today, to avoid the modern and potentially anachronistic connotations of that term. But “natural philosophy” (and its equivalents in different languages) was also an actor's category, a term commonly used throughout the early modern period and typically defined quite broadly as the study of natural bodies. As the central ...

  8. Framing nature

    NARCIS (Netherlands)

    Jansen, Peter

    2017-01-01

    This PhD thesis is about communication concerning nature in the Netherlands. The purpose of this exploratory study is to take both a theoretical and an empirical look at whether (implicit) religious elements play a role in this communication about nature in the Netherlands.

    In this PhD

  9. natural theology

    African Journals Online (AJOL)

    p1243322

    ancient Greece. The aim of this article is not to propose a new natural theology; nor does it seek to resurrect older models. It is necessary, however, to examine the extent to ... In studies like this one the South African context is relevant, as Barth is ... human reason to reach knowledge about God's nature and works insofar as.

  10. Nature Watch

    Indian Academy of Sciences (India)

    Nature Watch. When Dragons Fly ... K A Subramanian. A Natural History of Odonata. We have all held them by their wings, made them lift pebbles from our palms, tied their tails to paper flags and watched them flyaway, wondering all the while where and how they lived and what they did. I only knew that we called them ...

  11. Nature Detectives

    Science.gov (United States)

    Harr, Natalie; Lee, Richard E.; Jr.

    2010-01-01

    Richard Louv's "Last Child in the Woods" (2008) added to a growing consensus to get children outside and experiencing nature. Using ideas from place-based education, the authors present a simple year-long project that brings science, nature, and other curriculum standards to life right in your school yard. With a focus on journaling, this project…

  12. Matematica Natural.

    Science.gov (United States)

    Lozano, Patricia; Medearis, Linda

    Matematica Natural (Natural Mathematics) is a mathematics curriculum for young children based on the assumption that they learn mathematics through concrete, real life, relevant experiences and that educational differences rather than cultural differences influence math achievement. The curriculum uses hands-on materials and activities to teach…

  13. Natur formet

    DEFF Research Database (Denmark)

    Søberg, Martin

    2011-01-01

    Anmeldelse af Malene Hauxner, "Fra naturlig natur til SUPERNATUR – Europæisk landskabsarkitektur 1967-2007 set fra Danmark", Risskov: Ikaros Press, 2011.......Anmeldelse af Malene Hauxner, "Fra naturlig natur til SUPERNATUR – Europæisk landskabsarkitektur 1967-2007 set fra Danmark", Risskov: Ikaros Press, 2011....

  14. Framing nature

    NARCIS (Netherlands)

    Jansen, Peter

    2017-01-01

    This PhD thesis is about communication concerning nature in the Netherlands. The purpose of this exploratory study is to take both a theoretical and an empirical look at whether (implicit) religious elements play a role in this communication about nature in the Netherlands.   In this PhD thesis

  15. Dissonant Nature

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2013-01-01

    Nature restoration is far from being a neural undertaking. Just like any other type of heritage production it can be the source of dissonance – ‘our’ nature is not necessary ‘their’ nature. Often this dissonance is managed in ways, which are not particular sensitive to site......-specificity. As exemplified by the Skjern River Restoration Project (1999-2003), one interpretation of the landscape sometimes suppresses other valid interpretations neglecting its diverse history. Landscape architecture might, however, provide an alternative approach to nature restoration that is more site specific...... and allows for multiple interpretations to coexist. Evidence can be found in the Re-naturalization of River Aire (2002-2015), a restoration project, which reveals approaches that could be labelled landscape architecture specific....

  16. Writing Nature

    Directory of Open Access Journals (Sweden)

    Kristin Asdal

    2014-06-01

    Full Text Available This special issue of the Nordic Journal of Science and Technology Studies is interested in how nature, in different versions and forms, is invited into our studies, analyses, and stories. How is it that we “write nature”? How is it that we provide space for, and actually describe the actors, agents, or surroundings, in our stories and analyses? The articles in the issue each deal with different understandings of both the practices of writing and the introduction of various natures into these. In this introduction to the issue the editors engage with actor-network theory as a material semiotic resource for writing nature. We propose to foreground actor-network theory as a writing tool, at the expense of actor-network theory as a distinct vocabulary. In doing this and pointing out the semiotic origins to material-semiotics we also want to problematize a clear-cut material approach to writing nature.

  17. Natural Childbirth

    Science.gov (United States)

    ... Things That Help Feelings Expert Answers Q&A Movies & More for Teens Teens site Sitio para adolescentes ... the Pain? Print en español Parto natural Some women choose to give birth using no medications at ...

  18. Natural Communities

    Data.gov (United States)

    Kansas Data Access and Support Center — This dataset shows the locations of known tracts of high quality natural communities in Kansas, generalized to the PLSS section. It is not a compehensive dataset of...

  19. Pluralising Nature

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2017-01-01

    Denmark is recognised for its democratic approach to planning, and for the idea of planning for the common good. This interest in the common good and in common values also seems to be reflected in the way that the restoration of nature is planned and managed, suggesting that there is one common...... “nature” that everyone can agree on. But nature restoration is far from being an unproblematic undertaking. As with any other type of heritage production, it can be the source of dissonance. As exemplified by the Skjern River Restoration Project, one perception of a landscape and its value as “nature” can...... suppress other valid perceptions, in conflict with the need for different groups of people to be able to identify with the same territory. However, planning for the common good, in the case of nature restoration, does not necessarily mean planning for one common nature. Understanding and working...

  20. Natural Propositions

    DEFF Research Database (Denmark)

    Stjernfelt, Frederik

    Preface -- Introduction -- The generality of signs -- Dicisigns -- Some consequences of the dicisign doctrine -- Dicisigns and cognition -- Natural propositions--the evolution of semiotic self-control -- Dicisigns beyond language -- Operational and optimal iconicity in Peirce's diagrammatology...

  1. Natural aphrodisiacs.

    Science.gov (United States)

    Shamloul, Rany

    2010-01-01

    The search for a remedy or a prescription that can enhance sexual function and/or treat male erectile dysfunction has been an obsession throughout known history. Whether it was an Eastern civilization or a Western one, religious or atheist, man's aspiration for a better or best "manhood" has been a history-time goal. This review will discuss the current research done on the most popular natural aphrodisiacs and examine the weight of evidence to support or discourage the use of any of these substances to enhance sexual desire and/or function. Review of the current evidence on the use of natural substances as aphrodisiacs. Efficacy of natural aphrodisiacs in enhancing sexual function in men and women. There is little evidence from literature to recommend the usage of natural aphrodisiacs for the enhancement of sexual desire and/or performance. Data on yohimbine's efficacy does not support the wide use of the drug, which has only mild effects in the treatment of psychogenic ED. Although there's a positive trend towards recommending ginseng as an effective aphrodisiac, however, more in depth studies involving large number of subjects and its mechanism of action are needed before definite conclusions could be reached. Data on the use of natural aphrodisiacs in women is limited. The current body of objective evidence does not support the use of any natural aphrodisiac as an effective treatment for male or female sexual dysfunctions. Potent men and men with ED will continue the search for natural aphrodisiacs despite the current disappointing data on their effectiveness. Care should be taken regarding the fraud addition of sildenafil analogues to natural aphrodisiacs.

  2. The influence of the surgical operating microscope in locating the mesiolingual canal orifice: a laboratory analysis Influência do microscópio cirúrgico na localização do canal mesiopalatino: uma análise laboratorial

    Directory of Open Access Journals (Sweden)

    Tauby Coutinho Filho

    2006-03-01

    Full Text Available The aim of this study was to evaluate the influence of using the surgical operating microscope (SOM for detection of the mesiolingual (ML canal orifice in extracted first maxillary permanent molars. One hundred and eight human first maxillary permanent molars were randomly selected and mounted onto a dental chair mannequin. Conventional access cavity was prepared and an attempt was made to locate the mesiolingual canal orifice using only a sharp explorer, a mirror and a #10 K-file. A mesiolingual canal orifice was either located or not located. If not located, the teeth were then evaluated by using a surgical operating microscope (SOM. The mesiobuccal roots of all teeth where the ML canal orifice had not been located were sectioned in an axial plane and the sections were explored with an adjunctive use of the SOM at a 25 X magnification. ML canal orifices were detected in 58 teeth using only a sharp explorer, a mirror and #10 K-file. In the remaining 50 teeth, 37 ML canal orifices were located by using the SOM and 3 ML canal orifices were located after root sectioning. In 10 teeth, the ML canal orifices were not found. The results of this study showed a high incidence of a ML canal in the mesiobuccal roots of the first maxillary molars (90.7% and demonstrated that the adjunctive use of the SOM increased the ability of the dental clinician to locate the ML canal orifice.O objetivo deste estudo foi avaliar a influência do uso do microscópio cirúrgico na localização do canal mesiopalatino (MP em primeiros molares superiores humanos permanentes extraídos. Cento e oito primeiros molares superiores permanentes foram selecionados aleatoriamente e montados em um manequim dental. Uma cavidade de acesso convencional foi realizada e uma tentativa de se localizar o canal mesiopalatino foi feita, utilizando-se somente uma sonda exploradora afiada, um odontoscópio e uma lima tipo K tamanho 10. Quando não localizado o referido canal, os dentes foram

  3. Natural Disaster and Natural Selection

    OpenAIRE

    Uchida, Hirofumi; Miyakawa, Daisuke; Hosono, Kaoru; Ono, Arito; Uchino, Taisuke; Uesugi, Iichiro

    2013-01-01

    In this paper, we investigate whether a natural selection mechanism works for firm exit. By using data of firms after a devastating earthquake, the Greeat Tohoku Earthquake, we examine the impact of firm efficiency on firm exit both inside and outside the earthquake-affected areas. We find evidence suggesting that more efficeint firms are less likely to exit both inside and outside the affected areas, which supports the natural selection mechanism. However, we also find that the mechanism is ...

  4. Eventos adversos e motivos de descarte relacionados ao reuso de produtos médicos hospitalares em angioplastia coronária Adverse events and reasons for discard related to the reuse of cardiac catheters in percutaneous transluminal coronary angioplasty

    Directory of Open Access Journals (Sweden)

    Margarete Ártico Batista

    2006-09-01

    Full Text Available OBJETIVO: Descrever os eventos adversos ocorridos durante e após angioplastia coronária (ATC, possivelmente relacionados ao reuso de produtos médico-hospitalares, além de quantificar e identificar os motivos de descarte em relação ao primeiro uso e ao reuso. MÉTODO: Foram estudados 60 pacientes, sendo que 29 (48,3% apresentavam angina instável, 27 (45% IAM e quatro (6,7% outros diagnósticos. Durante o procedimento e na permanência na Unidade Intensiva Coronariana, atentou-se à possibilidade de ocorrência dos eventos adversos febre, hipertensão, hipotensão, calafrios, sudorese, sangramento, náuseas e vômitos. Foram avaliados sete produtos médico-hospitalares: introdutor, cateter-guia, fio-guia 0.35, fio-guia 0.014, cateter- balão para angioplastia, seringa com manômetro para insuflar balão (indeflator e torneira de três vias (manifold. No total de produtos (76 de primeiro uso e 410 reprocessados, verificou-se se houve descarte e se isto ocorreu antes ou durante o procedimento e quais os motivos para tanto. Utilizou-se o teste Qui Quadrado, admitindo-se erro alfa de 5%. RESULTADOS: Vinte e seis pacientes apresentaram eventos adversos. A hipotensão foi o evento mais prevalente e ocorreu em 11(18,3% casos. Não houve, porém, significância estatística entre o evento adverso hipotensão e reuso ou não dos produtos médico-hospitalares. Por não estarem íntegros, foram descartados três produtos de primeiro uso e 55 produtos dos reutilizados. CONCLUSÃO: Os eventos adversos apresentados pelos pacientes submetidos à angioplastia não estão associados ao reuso dos produtos médico-hospitalares. A integridade e funcionalidade foram os motivos principais de descarte.OBJECTIVE: To describe the adverse effects that occur during and after percutaneous transluminal coronary angioplasty (PTCA possibly related to the reuse of medical equipment. An additional objective is to quantify and identify the reasons of discard in respect to

  5. Emancipating Nature

    DEFF Research Database (Denmark)

    Munk, Anders Kristian

    2012-01-01

    The issue of riverine flooding in the UK is closely tied up with computer simulations. Arguably, these modelling practices are ripe with the anticipation of nature. They aspire to pre-empt it, hence expect it to be ‘out there’, and ultimately work through formalized distillations of it – hydrodyn......The issue of riverine flooding in the UK is closely tied up with computer simulations. Arguably, these modelling practices are ripe with the anticipation of nature. They aspire to pre-empt it, hence expect it to be ‘out there’, and ultimately work through formalized distillations...... of it – hydrodynamic equations – which have their own anticipations and place their own demands on their modellers. Through the experience of a flood modelling apprenticeship I argue that the taking-place of such anticipations paradoxically relies on the birth of a hybrid, the model-modeller, and thus on a nature...

  6. Provincialising Nature

    DEFF Research Database (Denmark)

    Provincialising Nature: Multidisciplinary Approaches to the Politics of the Environment in Latin America offers a timely analysis of some of the crucial challenges, contradictions and promises within current environmental discourses and practices in the region. This book shows both challenging...... scenarios and original perspectives that have emerged in Latin America in relation to the globally urgent issues of climate change and the environmental crisis. Two interconnected analytical frameworks guide the discussions in the book: the relationship between nature, knowledge and identity and their role...

  7. Natural pedagogy.

    Science.gov (United States)

    Csibra, Gergely; Gergely, György

    2009-04-01

    We propose that human communication is specifically adapted to allow the transmission of generic knowledge between individuals. Such a communication system, which we call 'natural pedagogy', enables fast and efficient social learning of cognitively opaque cultural knowledge that would be hard to acquire relying on purely observational learning mechanisms alone. We argue that human infants are prepared to be at the receptive side of natural pedagogy (i) by being sensitive to ostensive signals that indicate that they are being addressed by communication, (ii) by developing referential expectations in ostensive contexts and (iii) by being biased to interpret ostensive-referential communication as conveying information that is kind-relevant and generalizable.

  8. Natural aerodynamics

    CERN Document Server

    Scorer, R S

    1958-01-01

    Natural Aerodynamics focuses on the mathematics of any problem in air motion.This book discusses the general form of the law of fluid motion, relationship between pressure and wind, production of vortex filaments, and conduction of vorticity by viscosity. The flow at moderate Reynolds numbers, turbulence in a stably stratified fluid, natural exploitation of atmospheric thermals, and plumes in turbulent crosswinds are also elaborated. This text likewise considers the waves produced by thermals, transformation of thin layer clouds, method of small perturbations, and dangers of extra-polation.Thi

  9. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 2. Nature Watch Decline of a Montane Ecosystem. Kartik Shanker. Feature Article Volume 2 Issue 2 February 1997 pp 75-82. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/02/0075-0082 ...

  10. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 8. Nature Watch - Hornbills – Giants Among the Forest Birds. T R Shankar Raman Divya Mudappa. Feature Article Volume 3 Issue 8 August 1998 pp 56-65. Fulltext. Click here to view fulltext PDF. Permanent link:

  11. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 9. Nature Watch - Coral Reefs and their Fauna: An Underwater Fantasyland. Anuradha Bhat. Feature Article Volume 9 Issue 9 September 2004 pp 62-73. Fulltext. Click here to view fulltext PDF. Permanent link:

  12. Nature Watch

    Indian Academy of Sciences (India)

    Annual Meetings · Mid Year Meetings · Discussion Meetings · Public Lectures · Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 7. Nature Watch - Tent-making Bats. N Gopukumar J Balasingh. Feature Article Volume 7 Issue ...

  13. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 3. Nature Watch Diversity of Bats. G Marimuthu. Feature Article Volume 1 Issue 3 March 1996 pp 103-110. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/001/03/0103-0110. Author Affiliations.

  14. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 5. Nature Watch Will the Meek Inherit the Earth? Kartik Shanker. Feature Article Volume 2 Issue 5 May 1997 pp 54-59. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/05/0054-0059 ...

  15. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 8. Nature Watch: On the Trail of Skinks of the Western Ghats. Anirudha Datta-Roy. Feature Article Volume 19 Issue 8 August 2014 pp 753-763. Fulltext. Click here to view fulltext PDF. Permanent link:

  16. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 3. Nature Watch Diversity of Bats. G Marimuthu. Feature Article Volume 1 Issue 3 March 1996 pp 103-110. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/03/0103-0110. Author Affiliations.

  17. Nature Watch

    Indian Academy of Sciences (India)

    After the 1960s man's attention was diverted towards the Thar ... effects also. The alluvial and inter-dunal plains have gypsiferous hard pen sediments, which are responsible for serious water logging and salinity-alkalinity problems. Moreover, natural surface drainage system is absent and the ground water is highly saline.

  18. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 8. Nature Watch - Secrets of the Shieldtails. Kartik Shanker. Feature Article Volume 1 Issue 8 August 1996 pp 64-70. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/08/0064-0070 ...

  19. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 7. Nature Watch - Singapore's Jurong BirdPark: A Study Model. Abraham Verghese. Feature Article Volume 6 Issue 7 July 2001 pp 74-88. Fulltext. Click here to view fulltext PDF. Permanent link:

  20. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 7. Nature Watch - The Odyssey of the Olive Ridley. Kartik Shanker. Feature Article Volume 4 Issue 7 July 1999 pp 68-78. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/004/07/0068-0078 ...

  1. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 12. Nature Watch - Sarus Crane: On its Way to Extinction. Alok Kumar Mishra. Feature Article Volume 14 Issue 12 December 2009 pp 1206-1209. Fulltext. Click here to view fulltext PDF. Permanent link:

  2. Kritikkens natur

    DEFF Research Database (Denmark)

    Schatz-Jakobsen, Claus

    1999-01-01

    Artiklen introducerer det nye forskningsfelt inden for samtænkning af litteratur, kultur og natur, den såkaldt økologiske kritik, og kaster et kritisk blik på  dens brug af romantisk litteratur som proto-økologisk kanon....

  3. Nature Watch

    Indian Academy of Sciences (India)

    Nature Watch - Tracking Turtles through Time and Space. Kartik Shanker. General Article Volume 7 Issue 6 June 2002 ... Keywords. Turtles; animal navigation; conservation biology; nesting behaviour; telemetry. Author Affiliations. Kartik Shanker1. Wildlife Institute of India PO Box 18, Chandrabani Dehradun 248001, India.

  4. Nature Watch

    Indian Academy of Sciences (India)

    ... Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 5. Nature Watch - Thinking Like a Tahr: When Males and Females go their Separate Ways. M D Madhusudan. Feature Article Volume 3 Issue 5 May 1998 pp 43-47 ...

  5. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 10. Nature Watch The Amazing Desert Gerbil. Ishwar Prakash. Feature Article Volume 2 Issue 10 October 1997 pp 54-61. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/10/0054-0061 ...

  6. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 3. Nature Watch: Symbiosis in Coastal Marine Communities. Neelam Pereira. Feature Article Volume 20 Issue 3 March 2015 pp 245-253. Fulltext. Click here to view fulltext PDF. Permanent link:

  7. Natural fibers

    Science.gov (United States)

    Craig M. Clemons; Daniel F. Caulfield

    2005-01-01

    The term “natural fibers” covers a broad range of vegetable, animal, and mineral fibers. However, in the composites industry, it usually refers to wood fiber and agrobased bast, leaf, seed, and stem fibers. These fibers often contribute greatly to the structural performance of the plant and, when used in plastic composites, can provide significant reinforcement. Below...

  8. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 8. Nature Watch - Secrets of the Shieldtails. Kartik Shanker. Feature Article Volume 1 Issue 8 August 1996 pp 64-70. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/001/08/0064-0070 ...

  9. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 10. Nature Watch - When Dragons Fly. K A Subramanian. Feature Article Volume 7 Issue 10 October 2002 pp 69-78. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/10/0069-0078 ...

  10. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 8. Nature Watch - The Treasures of the Night Sky. P N Shankar B S Shylaja. Feature Article Volume 6 Issue 8 August 2001 pp 82-89. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/006/08/0082- ...

  11. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 1. Nature Watch The Kokum Tree. M D Subash Chandran. Feature Article Volume 1 Issue 1 January 1996 pp 86-89. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/001/01/0086-0089 ...

  12. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 7. Nature Watch - On Observing the Night Sky. P N Shankar B S Shylaja. Feature Article Volume 6 Issue 7 July 2001 pp 89-96. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/006/07/0089-0096 ...

  13. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 4. Nature Watch The Ancient Mariners. Kartik Shanker. Feature Article Volume 1 Issue 4 April 1996 pp 50-57. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/001/04/0050-0057. Author Affiliations.

  14. Nature Watch

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... ... 20; Issue 1. Nature Watch: A Tale of Two Turtles. V Deepak. Feature Article Volume 20 Issue 1 January 2015 pp 47-54. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/020/01/0047-0054. Keywords. Ecology; endemic; India; turtles; tortoises; Western Ghats.

  15. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 7. Nature Watch - The Odyssey of the Olive Ridley. Kartik Shanker. Feature Article Volume 4 Issue 7 July 1999 pp 68-78. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/004/07/0068-0078 ...

  16. Unbounded Naturalism

    Directory of Open Access Journals (Sweden)

    Andrew Taggart

    2008-10-01

    Full Text Available nbsp;font face="Times, serif"font size="3"In the Anglo-American reception of John McDowellrsquo;s /font/fontfont face="Times, serif"font size="3"emMind and World/em/font/fontfont face="Times, serif"font size="3", there has been little attention paid to the developmental aspect of his lsquo;partially re-enchantedrsquo; naturalism. In lsquo;Naturalism Unboundedrsquo;, I argue that McDowellrsquo;s story of our normal upbringing (/font/fontfont face="Times, serif"font size="3"emBildung/em/font/fontfont face="Times, serif"font size="3" presents problems for his claim that we have a lsquo;standing obligationrsquo; to reflect on our perceptual experiences. I follow this critique up with a Hegelian-inspired attempt to retain and revise the vital points he makes about experience./font/font

  17. Jagtens natur

    DEFF Research Database (Denmark)

    Gjerris, Mickey; Borkfelt, Sune; Gamborg, Christian

    2017-01-01

    Jagt kan ses som en konfrontation mellem menneskeverdenen og den vilde natur. I dag kan det dog være svært at få øje på det vilde i naturen i et land som Danmark, hvor over 60 % af det samlede areal anvendes til landbrug, og kun få pletter er overladt til sig selv. Ikke desto mindre spiller naturen...... en stor rolle for både jægerne og for de, der forholder sig kritisk til jagt. Der er stor enighed mellem disse parter om, at naturen er noget, vi skal tage vare på – men når det kommer til, hvilken natur der sigtes til, og hvordan vi skal tage vare på den, skilles vandene. Det skal bemærkes, at vi i...

  18. Natural games

    International Nuclear Information System (INIS)

    Anttila, Jani; Annila, Arto

    2011-01-01

    A course of a game is formulated as a physical process that will consume free energy in the least time. Accordingly, the rate of entropy increase is the payoff function that will subsume all forms of free energy that motivate diverse decisions. Also other concepts of game theory are related to their profound physical counterparts. When the physical portrayal of behavior is mathematically analyzed, the course of a game is found to be inherently unpredictable because each move affects motives in the future. Despite the non-holonomic character of the natural process, the objective of consuming free energy in the least time will direct an extensive-form game toward a Lyapunov-stable point that satisfies the minimax theorem. -- Highlights: → Behavior in the context of game theory is described as a natural process. → The rate of entropy increase, derived from statistical physics of open systems, is identified as the payoff function. → Entropy as the payoff function also clarifies motives of collaboration and subjective nature of decision making. → Evolutionary equation of motion that accounts for the course of a game is inherently unpredictable.

  19. Natural relaxation

    Science.gov (United States)

    Marzola, Luca; Raidal, Martti

    2016-11-01

    Motivated by natural inflation, we propose a relaxation mechanism consistent with inflationary cosmology that explains the hierarchy between the electroweak scale and Planck scale. This scenario is based on a selection mechanism that identifies the low-scale dynamics as the one that is screened from UV physics. The scenario also predicts the near-criticality and metastability of the Standard Model (SM) vacuum state, explaining the Higgs boson mass observed at the Large Hadron Collider (LHC). Once Majorana right-handed neutrinos are introduced to provide a viable reheating channel, our framework yields a corresponding mass scale that allows for the seesaw mechanism as well as for standard thermal leptogenesis. We argue that considering singlet scalar dark matter extensions of the proposed scenario could solve the vacuum stability problem and discuss how the cosmological constant problem is possibly addressed.

  20. Natural uranium

    International Nuclear Information System (INIS)

    Ammerich, Marc; Frot, Patricia; Gambini, Denis-Jean; Gauron, Christine; Moureaux, Patrick; Herbelet, Gilbert; Lahaye, Thierry; Pihet, Pascal; Rannou, Alain

    2014-08-01

    This sheet belongs to a collection which relates to the use of radionuclides essentially in unsealed sources. Its goal is to gather on a single document the most relevant information as well as the best prevention practices to be implemented. These sheets are made for the persons in charge of radiation protection: users, radioprotection-skill persons, labor physicians. Each sheet treats of: 1 - the radio-physical and biological properties; 2 - the main uses; 3 - the dosimetric parameters; 4 - the measurement; 5 - the protection means; 6 - the areas delimitation and monitoring; 7 - the personnel classification, training and monitoring; 8 - the effluents and wastes; 9 - the authorization and declaration administrative procedures; 10 - the transport; and 11 - the right conduct to adopt in case of incident or accident. This sheet deals specifically with natural uranium

  1. Natural isotopes

    International Nuclear Information System (INIS)

    Vogel, J.C.

    1986-01-01

    14 C dates between 600 and 900 AD were obtained for early Iron Age sites in Natal, and from 1300 to 1450 AD for rock engraving sites in Bushmanland. Palaeoenvironmental data derived from the dating of samples related to sedimentary and geomorphic features in the central and northern Namib Desert enabled the production of a tentative graph for the changes in humidity in the region over the past 40000 years. These results suggest that relatively humid conditions came to an end in the Namib at ±25000 BP (before present). The increased precision of the SIRA mass spectrometer enabled the remeasurement of 13 C and 18 O in the Cango stalagmite. This data confirmed that the environmental temperatures in the Southern Cape remained constant to within ±1 o C during the past 5500 years. Techniques and applications for environmental isotopes in hydrology were developed to determine the origin and movement of ground water. Isotopic fractionation effects in light elements in nature were investigated. The 15 N/ 14 N ratio in bones of animals and humans increases in proportion to the aridity of the environment. This suggests that 15 N in bone from dated archaeological sites could be used to detect changes in past climatic conditions as naturally formed nitrate minerals are higly soluble and are only preserved in special, very dry environments. The sources and sinks of CO 2 on the South African subcontinent were also determined. The 13 C/ 12 C ratios of air CO 2 obtained suggest that the vegetation provides the major proportion of respired CO 2 . 9 refs., 1 fig

  2. Complication related to colostomy orifice: intestinal evisceration

    Directory of Open Access Journals (Sweden)

    Valdemir José Alegre Salles

    2011-12-01

    Full Text Available Intestinal evisceration at the site of a stoma is a rare event, with high morbimortality. Its clinical manifestation often occurs between the sixth and seventh days after surgery. The risk factors most frequently related to evisceration are: increased intra-abdominal pressure, digestive tract cancer surgery, emergency surgery and stomas in the surgical incision. The authors report the case of a male patient, aged 62, suffering from adenocarcinoma of the rectum with obstructive acute abdomen, who underwent loop transversotomy for decompression. On the fourth day after surgery, he had a bronchospasm crisis, with evisceration of ileum and colon through the colostomic hole. The association of some triggering factors, such as emergency surgery, colorectal malignant neoplasm, increased intra-abdominal pressure and technical failure of colostomy were decisive in the development of this rare peri-colostomy complication.A evisceração intestinal desenvolvida no sítio de um estoma é um evento raro, tendo elevada morbimortalidade. Sua manifestação clínica ocorre frequentemente entre o sexto e o sétimo dias de pós-operatório. Os fatores de risco mais frequentemente relacionados à evisceração são: aumento da pressão intra-abdominal, câncer do aparelho digestório, cirurgia de urgência e estomias na incisão cirúrgica. Os autores relatam o caso de um paciente do sexo masculino, com 62 anos, portador de adenocarcinoma do reto médio com abdômen agudo obstrutivo, sendo submetido à transversostomia em alça, com finalidade descompressiva. No quarto dia de pós-operatório com crise de broncoespasmo, apresentou evisceração do cólon e íleo pelo orifício abdominal colostômico. A associação de alguns fatores desencadeantes, como a cirurgia de urgência, a doença neoplásica colorretal maligna, o aumento da pressão intra-abdominal e a falha técnica na confecção da colostomia, foram determinantes para o desenvolvimento desta rara complicação pericolostômica.

  3. 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...

  4. 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.

  5. Same Surgery - Altered Techniques; Past, Present and Future of Laparoscopic and Endoscopic Surgery

    Directory of Open Access Journals (Sweden)

    Fevzi Cengiz

    2013-01-01

    Full Text Available   From the first civilization on, tubes have been used in medicine for diagnosis and treatment. Rectal speculum was the first ever described endoscopic assessment method. Phillip Bozzini invented the first modern endoscope in1805,Antoine Jean Desormeaux invented a multipurpose endoscope by improving Bozzini’s Lichtleiter. Intraabdominal use of tubes(laparoscopy was started in1901 by Georg Kelling who first introduced the cystoscope into the abdominal space of a dog. Dramatic improvements were made in laparoscopic instruments and technique by studies of Kurt Semm. John E.A. Wickham used the term minimal invasive surgery for the first time in1983.The objective of this manuscript is to guide surgeons through transluminal approach which was established by simultaneous discovery of endoscopy and laparoscopy, and improved by the introduction of Natural Orifice Endoscopic Surgery (NOTES in 2004.

  6. 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 ......

  7. Submucosal tunneling techniques: current perspectives

    Directory of Open Access Journals (Sweden)

    Kobara H

    2014-04-01

    Full Text Available Hideki Kobara,1 Hirohito Mori,1 Kazi Rafiq,2 Shintaro Fujihara,1 Noriko Nishiyama,1 Maki Ayaki,1 Tatsuo Yachida,1 Tae Matsunaga,1 Johji Tani,1 Hisaaki Miyoshi,1 Hirohito Yoneyama,1 Asahiro Morishita,1 Makoto Oryu,1 Hisakazu Iwama,3 Tsutomu Masaki1 1Department of Gastroenterology and Neurology, 2Department of Pharmacology, 3Life Science Research Center, Faculty of Medicine, Kagawa University, Miki-cho, Kita-Gun, Kagawa, Japan Abstract: 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. Keywords: submucosal endoscopy, submucosal tunneling method, natural orifice transluminal endoscopic surgery, peroral endoscopic myotomy, gastrointestinal subepithelial tumor, functional and motility disorders

  8. Feasibility of NOTES omental plug repair of perforated peptic ulcers: results from a clinical pilot trial.

    Science.gov (United States)

    Bingener, Juliane; Loomis, Erica A; Gostout, Christopher J; Zielinski, Martin D; Buttar, Navtej S; Song, Louis M Wong Kee; Baron, Todd H; Ghahfarokhi, Leili Shahgholi; Rajan, Elizabeth

    2013-06-01

    Ulcer perforation carries up to a 30 % 1-year mortality rate. Intervention-related adverse events are among statistically significant predictors of 1-year mortality. A natural orifice transluminal endoscopic surgical (NOTES) approach may be less invasive and may decrease procedure-related adverse events by diminishing the so-called second hit, thus leading to decreased morbidity and mortality. We sought to assess the feasibility of an endoscopic transluminal omental plug technique in patients with perforated gastroduodenal ulcers under laparoscopic guidance. Patients with suspected acute gastroduodenal ulcer perforations were offered participation in this prospective pilot study. Closure of the perforation was attempted using the NOTES omental plug technique. Demographic, clinical, endoscopic, and radiographic data were abstracted, as were data for morbidity, mortality, and pilot data regarding quality of life (QOL). From February 2010 through February 2012, a total of 17 patients presented to a tertiary care center with clinically suspected perforated ulcer. Of seven patients (mean age 79 years, range 64-89 years) who consented to the study, three underwent the study procedure. All patients had multiple comorbidities. Two patients presented with 4-6 mm perforated peptic ulcers and underwent successful laparoscopic-assisted NOTES omental and falciform ligament patch closure, respectively. Postoperative radiographic contrast studies showed no leak, and patients were discharged home on postoperative days 3 and 4. The third patient had undergone enterocutaneous fistula repair with herniorrhaphy 6 weeks before. Although a transluminal endoscopic approach was feasible, the omentum was under too much tension to be secured. This procedure was converted to an open omental patch repair. For all but one patient who provided consent, obtaining QOL data was feasible. Initial results from a laparoscopic-assisted NOTES approach for closure of perforated peptic ulcers appear

  9. 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 t...

  10. Natural gas trends

    International Nuclear Information System (INIS)

    Anderson, A.

    1991-01-01

    This book provides data on many facets of the natural gas industry. Topics include: Canadian, Mexican; US natural gas reserves and production; Mexican and US natural gas consumption; market conditions for natural gas in the US; and Canadian natural gas exports

  11. Nonlinear friction modelling and compensation control of hysteresis phenomena for a pair of tendon-sheath actuated surgical robots

    Science.gov (United States)

    Do, T. N.; Tjahjowidodo, T.; Lau, M. W. S.; Phee, S. J.

    2015-08-01

    Natural Orifice Transluminal Endoscopic Surgery (NOTES) is a special method that allows surgical operations via natural orifices like mouth, anus, and vagina, without leaving visible scars. The use of flexible tendon-sheath mechanism (TSM) is common in these systems because of its light weight in structure, flexibility, and easy transmission of power. However, nonlinear friction and backlash hysteresis pose many challenges to control of such systems; in addition, they do not provide haptic feedback to assist the surgeon in the operation of the systems. In this paper, we propose a new dynamic friction model and backlash hysteresis nonlinearity for a pair of TSM to deal with these problems. The proposed friction model, unlike current approaches in the literature, is smooth and able to capture the force at near zero velocity when the system is stationary or operates at small motion. This model can be used to estimate the friction force for haptic feedback purpose. To improve the system tracking performances, a backlash hysteresis model will be introduced, which can be used in a feedforward controller scheme. The controller involves a simple computation of the inverse hysteresis model. The proposed models are configuration independent and able to capture the nonlinearities for arbitrary tendon-sheath shapes. A representative experimental setup is used to validate the proposed models and to demonstrate the improvement in position tracking accuracy and the possibility of providing desired force information at the distal end of a pair of TSM slave manipulator for haptic feedback to the surgeons.

  12. Per oral endoscopic myotomy for the treatment of achalasia.

    Science.gov (United States)

    Stavropoulos, Stavros N; Modayil, Rani; Friedel, David

    2015-09-01

    Per oral endoscopic myotomy (POEM) represents the culmination of natural orifice transluminal endoscopic surgery (NOTES) research, and its most successful application to date. Over a thousand POEMs have been performed globally with remarkable results in terms of clinical efficacy and safety. We examine the most recent literature concerning POEM since the last two comprehensive analyses [Natural Orifice Surgery Consortium for Assessment and Research (NOSCAR) White Paper, ASGE Preservation and Incorporation of Valuable endoscopic Innovations (PIVI)], and integrate this literature in the consensus POEM guidelines and perspective. These current works are largely centered on POEM operator learning curve, comparison of POEM and laparoscopic Heller myotomy (LHM) and extended application of POEM. POEM and LHM are comparable in terms of efficacy (diminished dysphagia and Eckardt score) and complications including GERD. POEM has been successfully performed in a wide variety of patients including children, those with prior achalasia therapy and those with spastic esophageal disorders. POEM has been validated as a treatment for achalasia. Issues remain regarding its longer term efficacy in comparison with LHM. Subsequent comparison trials are needed. http://links.lww.com/COG/A14.

  13. 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.

  14. 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.

  15. 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.

  16. What is 'Natural'in Natural Selection?

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 5. What is 'Natural' in Natural Selection? Abhijeet S Bardapurkar. Classroom Volume 18 Issue 5 May 2013 pp 475-482. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/018/05/0475-0482. Keywords.

  17. Natural and near natural tropical forest values

    Science.gov (United States)

    Daniel H. Henning

    2011-01-01

    This paper identifies and describes some of the values associated with tropical rain forests in their natural and near-natural conditions. Tropical rain forests are moist forests in the humid tropics where temperature and rainfall are high and the dry season is short. These closed (non-logged) and broad-leaved forests are a global resource. Located almost entirely in...

  18. Learning from nature: Nature-inspired algorithms

    DEFF Research Database (Denmark)

    Albeanu, Grigore; Madsen, Henrik; Popentiu-Vladicescu, Florin

    2016-01-01

    During last decade, the nature has inspired researchers to develop new algorithms. The largest collection of nature-inspired algorithms is biology-inspired: swarm intelligence (particle swarm optimization, ant colony optimization, cuckoo search, bees' algorithm, bat algorithm, firefly algorithm etc...

  19. Three Sorts of Naturalism

    DEFF Research Database (Denmark)

    Fink, Hans

    2006-01-01

    In "Two sorts of Naturalism" John McDowell is sketching his own sort of naturalism in ethics as an alternative to "bald naturalism". In this paper I distinguish materialist, idealist and absolute conceptions of nature and of naturalism in order to provide a framework for a clearer understanding...... of what McDowell's own naturalism amounts to. I argue that nothing short of an absolute naturalism will do for a number of McDowell's own purposes, but that it is far from obvious that this is his position. If he directly denies that it is, he seems to be left with some rather awkward choices....

  20. Three Sorts of Naturalism

    OpenAIRE

    Fink, Hans

    2006-01-01

    In "Two sorts of Naturalism" John McDowell is sketching his own sort of naturalism in ethics as an alternative to "bald naturalism". In this paper I distinguish materialist, idealist and absolute conceptions of nature and of naturalism in order to provide a framework for a clearer understanding of what McDowell's own naturalism amounts to. I argue that nothing short of an absolute naturalism will do for a number of McDowell's own purposes, but that it is far from obvious that this is his posi...

  1. 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

  2. Natural short sleeper

    Science.gov (United States)

    Sleep - natural short sleeper ... 7 to 9 hours of sleep each night. Short sleepers sleep less than 75% of what is normal for their age. Natural short sleepers are different from people who chronically do ...

  3. Natural gas annual 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-09-01

    This document provides information on the supply and disposition of natural gas to a wide audience. The 1996 data are presented in a sequence that follows natural gas from it`s production to it`s end use.

  4. Vermont Natural Resources Atlas

    Data.gov (United States)

    Vermont Center for Geographic Information — The purpose of the�Natural Resources Atlas�is to provide geographic information about environmental features and sites that the Vermont Agency of Natural Resources...

  5. Natural Weathering Exposure Station

    Data.gov (United States)

    Federal Laboratory Consortium — The Corps of Engineers' Treat Island Natural Weathering Exposure Station is a long-term natural weathering facility used to study concrete durability. Located on the...

  6. Natural Language Processing

    OpenAIRE

    Preeti; BrahmaleenKaurSidhu

    2013-01-01

    Natural language processing (NLP) work began more than sixty years ago; it is a field of computer science and linguistics devoted to creating computer systems that use human (natural) language. Natural Language Processing holds great promise for making computer interfaces that are easier to use for people, since people will be able to talk to the computer in their own language, rather than learn a specialized language of computer commands. Natural Language processing techniques can make possi...

  7. Natural gas annual 1993

    International Nuclear Information System (INIS)

    1994-01-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1993 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. Tables summarizing natural gas supply and disposition from 1989 to 1993 are given for each Census Division and each State. Annual historical data are shown at the national level

  8. Natural gas annual 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-17

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1994 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. This is followed by tables summarizing natural gas supply and disposition from 1990 to 1994 for each Census Division and each State. Annual historical data are shown at the national level.

  9. Natural gas annual 1995

    International Nuclear Information System (INIS)

    1996-11-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1995 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. This is followed by tables summarizing natural gas supply and disposition from 1991 to 1995 for each Census Division and each State. Annual historical data are shown at the national level

  10. Natural gas annual 1991

    International Nuclear Information System (INIS)

    1992-01-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1991 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. Tables summarizing natural gas supply and disposition form 1987 to 1991 are given for each Census Division and each State. Annual historical data are shown at the national level

  11. Natural Gas Basics

    Energy Technology Data Exchange (ETDEWEB)

    2016-06-01

    Natural gas powers about 150,000 vehicles in the United States and roughly 22 million vehicles worldwide. Natural gas vehicles (NGVs) are a good choice for high-mileage fleets -- such as buses, taxis, and refuse vehicles -- that are centrally fueled or operate within a limited area or along a route with natural gas fueling stations. This brochure highlights the advantages of natural gas as an alternative fuel, including its domestic availability, established distribution network, relatively low cost, and emissions benefits.

  12. Natural Gas Basics

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-06-08

    Natural gas powers about 150,000 vehicles in the United States and roughly 22 million vehicles worldwide. Natural gas vehicles (NGVs) are a good choice for high-mileage fleets -- such as buses, taxis, and refuse vehicles -- that are centrally fueled or operate within a limited area or along a route with natural gas fueling stations. This brochure highlights the advantages of natural gas as an alternative fuel, including its domestic availability, established distribution network, relatively low cost, and emissions benefits.

  13. Natural gas annual 1991

    International Nuclear Information System (INIS)

    1993-01-01

    The Natural Gas Annual 1991 provides information on the supply and disposition of natural gas to a wide audience including industry, consumers Federal and State agencies, and education institutions. This report, the Natural Gas Annual 1991 Supplement: Company Profiles, presents a detailed profile of selected companies

  14. Naturalisms and religion

    NARCIS (Netherlands)

    Drees, Willem

    1997-01-01

    Such terms as materialism, naturalism, and near synonyms evoke strong negative reactions among many believers. However, the notion of naturalism has various meanings; implications for religion differ for the several varieties of naturalism. In this paper I analyze epistemological and ontological

  15. Natural gas for vehicles

    International Nuclear Information System (INIS)

    Prieur, A.

    2006-01-01

    Following a decade-long upsurge in the use of natural gas in the energy sector (heating and especially electricity), new outlets for natural gas are being developed in the transport sector. For countries endowed with substantial local resources, development in this sector can help reduce oil dependence. In addition, natural gas is often used to reduce pollution, particularly in cities

  16. Nature and Health

    NARCIS (Netherlands)

    Hartig, T.; Mitchell, R.; Vries, de S.; Frumkin, H.

    2014-01-01

    Urbanization, resource exploitation, and lifestyle changes have diminished possibilities for human contact with nature in urbanized societies. Concern about the loss has helped motivate research on the health benefits of contact with nature. Reviewing that research here, we focus on nature as

  17. Capturing Nature's Diversity

    Science.gov (United States)

    Pascolutti, Mauro; Campitelli, Marc; Nguyen, Bao; Pham, Ngoc; Gorse, Alain-Dominique; Quinn, Ronald J.

    2015-01-01

    Natural products are universally recognized to contribute valuable chemical diversity to the design of molecular screening libraries. The analysis undertaken in this work, provides a foundation for the generation of fragment screening libraries that capture the diverse range of molecular recognition building blocks embedded within natural products. Physicochemical properties were used to select fragment-sized natural products from a database of known natural products (Dictionary of Natural Products). PCA analysis was used to illustrate the positioning of the fragment subset within the property space of the non-fragment sized natural products in the dataset. Structural diversity was analysed by three distinct methods: atom function analysis, using pharmacophore fingerprints, atom type analysis, using radial fingerprints, and scaffold analysis. Small pharmacophore triplets, representing the range of chemical features present in natural products that are capable of engaging in molecular interactions with small, contiguous areas of protein binding surfaces, were analysed. We demonstrate that fragment-sized natural products capture more than half of the small pharmacophore triplet diversity observed in non fragment-sized natural product datasets. Atom type analysis using radial fingerprints was represented by a self-organizing map. We examined the structural diversity of non-flat fragment-sized natural product scaffolds, rich in sp3 configured centres. From these results we demonstrate that 2-ring fragment-sized natural products effectively balance the opposing characteristics of minimal complexity and broad structural diversity when compared to the larger, more complex fragment-like natural products. These naturally-derived fragments could be used as the starting point for the generation of a highly diverse library with the scope for further medicinal chemistry elaboration due to their minimal structural complexity. This study highlights the possibility to capture a

  18. Nature in Preschool

    DEFF Research Database (Denmark)

    Husted, Mia; Frøkjær, Thorleif

    Nature and nature phenomena’ has formed a specific curriculum theme in Danish preschool since early childhood curriculum was prescribed by law in 2004. However, recent evaluations show that the implementation of an early childhood curriculum has not produced an increased pedagogical focus...... on ‘nature and nature phenomena’ in preschools (EVA 2012). This finding, along with an increased political interest in goals and measurable outcome of early childhood curriculum (Broström 2012), will be the starting point in our ambition to carry out a more thorough qualitative investigation into links...... between preschool teachers’ understanding and interest in teaching nature and the rather poor evaluation....

  19. Natural gas marketing II

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This book covers all aspects of gas marketing, from the basic regulatory structure to the latest developments in negotiating agreements and locating markets. Topics include: Federal regulation of the gas industry; Fundamentals of gas marketing contracts; FERC actions encouraging competitive markets; Marketing conditions from the pipelines' perspective; State non-utility regulation of natural gas production, transportation, and marketing; Natural gas wellhead agreements and tariffs; Natural gas processing agreements; Effective management of producer's natural gas contracts; Producer-pipeline litigation; Natural gas purchasing from the perspective of industrial gas users; Gas marketing by co-owners: problems of disproportionate sales, gas balancing, and accounting to royalty owners; Alternatives and new directions in marketing

  20. On nature and bioethics.

    Science.gov (United States)

    Peterson, Paul Silas

    2010-01-01

    The account of nature and humanity's relationship to nature are of central importance for bioethics. The Scientific Revolution was a critical development in the history of this question and many contemporary accounts of nature find their beginnings here. While the innovative approach to nature going out of the seventeenth century was reliant upon accounts of nature from the early modern period, the Middle Ages, late-antiquity and antiquity, it also parted ways with some of the understandings of nature from these epochs. Here I analyze this development and suggests that some of the insights from older understandings of nature may be helpful for bioethics today, even if there can be no simple return to them.

  1. Nature as Dissonant Heritage

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    Many former sites of land reclamation, where rivers and wetlands have been cultivated for the purpose of modern agriculture, are now subject to projects of nature restoration. In this context nature is often referred to as ‘the nature’ or simply ‘nature’ as it was something objective and self......-evident. But who define and decide what kind of nature to restore? And is nature restoration not a contradiction in terms in our deeply cultivated landscapes? To examine these questions it makes sense to draw parallels between nature restoration and the concept of ‘dissonant heritage’ (Ashworth 2010), which...... concerns situations of mismatch between people and their heritage. The aim of the paper is to uncover the latent cultural dissonance in relation to nature restoration and to explain how landscape architecture could play an important role in the management of this dissonance. If one accepts that heritage...

  2. Nature and health.

    Science.gov (United States)

    Hartig, Terry; Mitchell, Richard; de Vries, Sjerp; Frumkin, Howard

    2014-01-01

    Urbanization, resource exploitation, and lifestyle changes have diminished possibilities for human contact with nature in urbanized societies. Concern about the loss has helped motivate research on the health benefits of contact with nature. Reviewing that research here, we focus on nature as represented by aspects of the physical environment relevant to planning, design, and policy measures that serve broad segments of urbanized societies. We discuss difficulties in defining "nature" and reasons for the current expansion of the research field, and we assess available reviews. We then consider research on pathways between nature and health involving air quality, physical activity, social cohesion, and stress reduction. Finally, we discuss methodological issues and priorities for future research. The extant research does describe an array of benefits of contact with nature, and evidence regarding some benefits is strong; however, some findings indicate caution is needed in applying beliefs about those benefits, and substantial gaps in knowledge remain.

  3. Natural gas annual 1997

    International Nuclear Information System (INIS)

    1998-10-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1997 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. This is followed by tables summarizing natural gas supply and disposition from 1993 to 1997 for each Census Division and each State. Annual historical data are shown at the national level. 27 figs., 109 tabs

  4. The City and Nature

    Directory of Open Access Journals (Sweden)

    Eduard Tovmasyan

    2016-09-01

    Full Text Available Animate “nature–1” around us is transforming into supported or non-supported by man “nature-2” within the framework of the urban development of town areas. Interaction of town and nature is a bilateral process. Experts underline 4 groups of town planning risks related to the interaction of town and nature: ecological, natural and biosphere, sanitary-epidemiologic risks as well as planning and management risks. The latter is often connected with protest population activities. The magazine is looking forward to readers comments.

  5. Natural gas outlook

    International Nuclear Information System (INIS)

    Molyneaux, M.P.

    1998-01-01

    An overview of natural gas markets in Canada and in the United States was provided. The major factors that determine the direction of natural gas prices were depicted graphically. Price volatility has decreased in recent months. As expected, April through November total energy consumption reached historically high levels. Demand for natural gas during the summer of 1997 was not as strong as anticipated. Nuclear energy appears to be on the slippery slope, with natural gas-driven electricity projects to fill the void. Hydroelectricity had a strong showing in 1997. Prospects are less bright for 1998 due to above average temperatures. Canadian natural gas export capacity has increased 5.5 times between 1986 and estimated 1999 levels. Despite this, in 1997, deliveries to the United States were marginally behind expectations. Natural gas consumption, comparative fuel prices, natural gas drilling activity, natural gas storage capacity, actual storage by region, and average weekly spot natural gas prices, for both the U. S. and Canada, were also provided. With regard to Canada, it was suggested that Canadian producers are well positioned for a significant increase in their price realization mostly because of the increase in Canada's export capacity in 1997 (+175 Mmcf/d), 1998 (1,060 Mmcf/d) and potentially in 1999 or 2000, via the Alliance Pipeline project. Nevertheless, with current production projections it appears next to impossible to fill the 10.9 Bcf/d of export capacity that will be potentially in place by the end of 1999. tabs., figs

  6. Nature-based integration

    DEFF Research Database (Denmark)

    Pitkänen, Kati; Oratuomi, Joose; Hellgren, Daniela

    Increased attention to, and careful planning of the integration of migrants into Nordic societies is ever more important. Nature based integration is a new solution to respond to this need. This report presents the results of a Nordic survey and workshop and illustrates current practices of nature...... based integration by case study descriptions from Denmark, Sweden Norway and Finland. Across Nordic countries several practical projects and initiatives have been launched to promote the benefits of nature in integration and there is also growing academic interest in the topic. Nordic countries have...... the potential of becoming real forerunners in nature based integration even at the global scale....

  7. Early modern natural history

    Indian Academy of Sciences (India)

    Early modern natural history: Contributions from the Americas and India. Rajesh Kochhar. Perspectives Volume 37 Issue ... Keywords. India; medical botany; natural history; scientific botany; the Americas. Author Affiliations. Rajesh Kochhar1. Indian Institute of Science Education and Research, Mohali 140 306 Punjab, India ...

  8. Nature Foil Reliefs

    Science.gov (United States)

    Lane, Shaw J.

    2012-01-01

    Nature has always been a source of inspiration for artists across the centuries. Artists such as Leonardo da Vinci, Georgia O'Keeffe, Ansel Adams, and Andy Goldsworthy all drew inspiration for their work from nature. Seeds come from the dried pods, which when planted and cared for, bear fruit. In this article, the author describes how her…

  9. SUIKERBOSRAND NATURE RESERVE

    African Journals Online (AJOL)

    Suikerbosrand Nature Reserve and fts educational facilities are run by the Transvaal. Division of. Nature Conservation. ... tion and the education facilities provided. The former are utilized mainly by the general public ... artist Paul Bosman (already reviewed in the EEASA newsletter). The co-founders of the Foundation are.

  10. European natural gas

    International Nuclear Information System (INIS)

    Thackeray, Fred

    1999-11-01

    Contains Executive Summary and Chapters on: Main issues; Natural gas consumption and supply: statistics and key features of individual countries; Sectoral natural gas consumption; Indigenous production; Imports; Prices and taxes; The spot market: The interconnector; Forecasts of production and consumption and contracted imports; Progress of markets liberalisation; Effects of environmentalist developments; Transmission networks and storage; Some principal players. (Author)

  11. Natural Ventilation in Atria

    DEFF Research Database (Denmark)

    Svidt, Kjeld; Heiselberg, Per; Hendriksen, Ole Juhl

    This case study comprises a monitoring programme as well as a Computational Fluid Dynamics (CFD) analysis of a natural ventilated atrium. The purpose has been to analyse the performance of a typical natural ventilation system in Denmark under both summer and winter conditions....

  12. Nature and landscape protection

    International Nuclear Information System (INIS)

    Klinda, J.; Lieskovska, Z.

    1998-01-01

    In accordance with National Council of the Slovak Republic Act N. 287/1994 Coll. on Nature and Landscape Protection, the system of complex nature landscape protection has been designed based on five levels of protection. Categories of protected areas as well as cultural monuments in the Slovak Republic are reviewed.Slovak contribution to the world heritage is included

  13. Exposure to natural radiation

    International Nuclear Information System (INIS)

    Green, B.M.R.

    1985-01-01

    A brief report is given of a seminar on the exposure to enhanced natural radiation and its regulatory implications held in 1985 at Maastricht, the Netherlands. The themes of the working sessions included sources of enhanced natural radiation, parameters influencing human exposure, measurement and survey programmes, technical countermeasures, risk and assessment studies, philosophies of dose limitations and national and international policies. (U.K.)

  14. Chemistry of Natural Dyes

    Indian Academy of Sciences (India)

    The sulfonated oils, which possess better metal bind- ing capacity than the natural oils due to the presence of sulfonic acid group, bind to metal ions forming a complex with the dye to give superior fastness and hue. Limitations of Natural Dyes. Tedious extraction of colouring component from the raw mate- rial, low colour ...

  15. Archives: Sciences & Nature

    African Journals Online (AJOL)

    Items 1 - 9 of 9 ... Archives: Sciences & Nature. Journal Home > Archives: Sciences & Nature. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives. 1 - 9 of 9 Items. 2011. Vol 8, No 1-2 ...

  16. Modeling Natural Selection

    Science.gov (United States)

    Bogiages, Christopher A.; Lotter, Christine

    2011-01-01

    In their research, scientists generate, test, and modify scientific models. These models can be shared with others and demonstrate a scientist's understanding of how the natural world works. Similarly, students can generate and modify models to gain a better understanding of the content, process, and nature of science (Kenyon, Schwarz, and Hug…

  17. Nature as Measure

    DEFF Research Database (Denmark)

    Peters, Terri

    2011-01-01

    The potential for biomimicry lies far beyond the direct imitation of natural forms. Guest-editor Terri Peters describes how Janine Benyus, the biologist and innovation consultant, is using biomimicry to create performance metrics from natural technologies and processes for assessing aspects...

  18. Revenge of Mother Nature

    DEFF Research Database (Denmark)

    Hansen, Kim Toft

    2018-01-01

    by employing the well-known mythical trope of the forest. This specific attention towards nature, the forest and the Swedish landscape not only establishes a supernatural sense of place and nature. While creating a generic hybrid between crime fiction and tropes and motifs from the horror genre and what has...... been dubbed ecohorror (Murray & Heumann 2016; Crosby 2014), the supernaturalisation of the landscape in both series establishes an ecocriti-cal consideration of retaliating nature reacting against human interference with nature. The visual etymology of such place sensibilities reaches back in Nordic...... landscape iconography with an obvious relationship with the notion of the Nordic sublime in romantic landscape painting (Alsen & Landmann 2016). These dramas address nature and ecocritical issues by way of a supernature with agency....

  19. Nature teaching structures

    DEFF Research Database (Denmark)

    Wester, Ture

    2002-01-01

    -living nature a number of striking statical and kinematical peculiarities have been observed. The paper will try to isolate and describe some of these observations and their relation to our engineered structures based on human thinking. The paper will deal with basic aspects as geometry, topology, redundancy...... and rare piece of fine architecture - or a common organism in Nature. That is why Nature makes an excellent object for architectural students to study structures from a conceptual and a morphological point of view. And that is why Nature - who has developed her structural systems by trial-and-error through...... millions of years - acts as an excellent teacher of these topics. At the same time, the idiom of Nature seems to possess a considerable attraction for students and is able to convey inspiration and imagination to the creative process of shaping architectural structures. In our surrounding living and non...

  20. Unnaturalised racial naturalism.

    Science.gov (United States)

    Hochman, Adam

    2014-06-01

    Quayshawn Spencer (2014) misunderstands my treatment of racial naturalism. I argued that racial naturalism must entail a strong claim, such as "races are subspecies", if it is to be a substantive position that contrasts with anti-realism about biological race. My recognition that not all race naturalists make such a strong claim is evident throughout the article Spencer reviews (Hochman, 2013a). Spencer seems to agree with me that there are no human subspecies, and he endorses a weaker form of racial naturalism. However, he supports his preferred version of 'racial naturalism' with arguments that are not well described as 'naturalistic'. I argue that Spencer offers us an unnaturalised racial naturalism. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Perkutan transluminal embolisering af pulmonale arteriovenøse misdannelser

    DEFF Research Database (Denmark)

    Kjeldsen, A D; Andersen, P E; Oxhøj, H

    1998-01-01

    , due to lack of the normal filter function of the lung, paradoxical embolism. Women are particularly at risk during pregnancy. Among patients with Hereditary Haemorrhagic Telangiectasia 15-33% also have PAVM. Embolotherapy is a safe and efficacious treatment for occlusion of PAVM. Since serious...

  2. Intravaskulaer ultralyd og perkutan transluminal angioplastik. Praeliminaere resultater

    DEFF Research Database (Denmark)

    Vogt, K C; Rasmussen, John Bøje Grønvall; Just, S R

    1995-01-01

    PTA. Comparing IVUS with angiography revealed an acceptable agreement in quantifying stenoses before the intervention but not after. We conclude that IVUS is a feasible method to evaluate stenosis in blood vessels before and after PTA. By supplying additional information to angiography, it may improve...

  3. Acute complications of percutaneous transluminal coronary angioplasty for total occlusion

    NARCIS (Netherlands)

    S. Plante (Sylvain); G-J. Laarman (GertJan); P.J. de Feyter (Pim); M. Samson; B.J.W.M. Rensing (Benno); V.A.W.M. Umans (Victor); H. Suryapranata (Harry); M.J.B.M. van den Brand (Marcel); P.W.J.C. Serruys (Patrick)

    1991-01-01

    markdownabstractAbstract The incidence of major complications after percutaneous coronary angioplasty (PTCA) of a totally occluded artery was assessed retrospectively. A total of 1649 PTCA procedures were analyzed. After exclusion of procedures for acute myocardial infarction or total occlusion

  4. Transluminal angioplasty of a stenotic surgical splenorenal shunt

    International Nuclear Information System (INIS)

    Beers, B. van; Roche, A.; Cauquil, P.

    1988-01-01

    A stenosis of a side-to-side splenorenal shunt was treated by percutaneous angioplasty two years after the performance of the shunt. After dilatation, there was a fall of the splenorenal pressure gradient from 28 to 17 cm H 2 O and good transanastomotic flow was re-estabilshed. As in other arterial and venous territories, angioplasty may be an interesting alternative to surgery. (orig.)

  5. Almacenamiento de gas natural

    Directory of Open Access Journals (Sweden)

    Tomás Correa

    2008-12-01

    Full Text Available The largest reserves of natural gas worldwide are found in regions far of main cities, being necessary different alternatives to transport the fluid to the consumption cities, such as pipelines, CNG or ships, LNG, depending on distances between producing regions and demanding regions and the producing volumes. Consumption regions have three different markets to naturalgas; residential and commercial, industrial and power generation sector. The residential and commercial is highly seasonal and power generation sector is quite variable depending on increases of temperature during summer time. There are also external issuesthat affect the normal gas flow such as fails on the national system or unexpected interruptions on it, what imply that companies which distribute natural gas should design plans that allow supplying the requirements above mentioned. One plan is using underground natural gas storage with capacities and deliverability rates enough to supply demands. In Colombia there are no laws in this sense but it could be an exploration to discuss different ways to store gas either way as underground natural gas storage or above superficies. Existing basically three different types of underground natural gas storage; depleted reservoirs, salt caverns and aquifers. All ofthem are adequate according to geological characteristics and the needs of the distributors companies of natural gas. This paper is anexploration of technical and economical characteristics of different kind of storages used to store natural gas worldwide.

  6. Natural gas in Mexico

    International Nuclear Information System (INIS)

    Ramirez, M.

    1999-01-01

    A series of overhead viewgraphs accompanied this presentation which focused on various aspects of the natural gas industry in Mexico. Some of the viewgraphs depicted statistics from 1998 regarding natural gas throughput from various companies in North America, natural gas reserves around the world, and natural gas reserves in Mexico. Other viewgraphs depicted associated and non-associated natural gas production from 1988 to 1998 in million cubic feet per day. The Burgos Basin and the Cantarell Basin gas production from 1997 to 2004 was also depicted. Other viewgraphs were entitled: (1) gas processing infrastructure for 1999, (2) cryogenic plant at Cd. PEMEX, (3) average annual growth of dry natural gas production for 1997-2004 is estimated at 5.2 per cent, (4) gas flows for December 1998, (5) PGPB- interconnect points, (6) U.S. Mexico gas trade for 1994-1998, (7) PGPB's interconnect projects with U.S., and (8) natural gas storage areas. Technological innovations in the industry include more efficient gas turbines which allow for cogeneration, heat recovery steam generators which reduce pollutant emissions by 21 per cent, cold boxes which increase heat transfer efficiency, and lateral reboilers which reduce energy consumption and total costs. A pie chart depicting natural gas demand by sector shows that natural gas for power generation will increase from 16 per cent in 1997 to 31 per cent in 2004. The opportunities for cogeneration projects were also reviewed. The Comision Federal de Electricidad and independent power producers represent the largest opportunity. The 1997-2001 investment program proposes an 85 per cent sulphur dioxide emission reduction compared to 1997 levels. This presentation also noted that during the 1998-2001 period, total ethane production will grow by 58 tbd. 31 figs

  7. Living in cities, naturally.

    Science.gov (United States)

    Hartig, Terry; Kahn, Peter H

    2016-05-20

    Natural features, settings, and processes in urban areas can help to reduce stress associated with urban life. In this and other ways, public health benefits from, street trees, green roofs, community gardens, parks and open spaces, and extensive connective pathways for walking and biking. Such urban design provisions can also yield ecological benefits, not only directly but also through the role they play in shaping attitudes toward the environment and environmental protection. Knowledge of the psychological benefits of nature experience supports efforts to better integrate nature into the architecture, infrastructure, and public spaces of urban areas. Copyright © 2016, American Association for the Advancement of Science.

  8. EEC's: natural uramium supplies

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The demand for nuclear fuel to supply the nuclear plants within the ECC (31,200 MW at the end of last year) totalled nearly 9,600 tons of natural uranium and 4,900 of separation work units (SWU). Once reactors currently under construction come into service, the demand for natural uranium will reach 13,200 tons by 1985 and that for SWUs to 8,600. If one takes the years 1981 to 1985, total natural uranium needs during this period will be 56,300 tons and those for SWUs 35.100 [fr

  9. Closer to Nature?

    DEFF Research Database (Denmark)

    Borkfelt, Sune; Kondrup, Sara; Röcklinsberg, Helena

    2015-01-01

    discourses in order to sell one image of animal welfare in intensive animal production while the actual production at the same time presupposes a quite different paradigm of animal welfare. Specifically, product advertising utilizes representations tied to concepts of naturalness in depictions of both animal...... lives and product processes as “natural”. Product marketing suggests a coherence between nature, production process (farm, animal), and end product, thereby creating associations that the lives of production animals are lived in nature and that their products bring a wholesome and sustainable...

  10. Structural patterns in nature

    DEFF Research Database (Denmark)

    Wester, Ture

    2003-01-01

    It seemens that some very basic randomly produced geometric/topological patterns are commonly found in Nature and have often very distinctive structural qualities. In Nature we find the same pattern in all scales from the universe to molecules, from solar systems to packing of cells, from glaciers...... to sea shells, from river systems to trees etc. Sometimes this seeming archetypical morphology involve structrual action and sometimes not-but the fact that it often posses efficient structural action opens a tool for evaluation and analysis of structures in nature and at the same time might...

  11. Structural patterns in nature

    DEFF Research Database (Denmark)

    Wester, Ture

    2004-01-01

    It seems that some very basic randomly produced geometric/topological patterns are commonly found in Nature and have often very distinctive structural qualities. In nature we find the same pattern in all scales from the universe to molecules, from solar systems to packing of cells, from glaciers...... to sea shells, from river systems to trees etc. Sometimes this seeming archetypical morphology involve structural action and sometimes not - but the fact that it often posses efficient structural action opens a tool for evaluation and analyses of structures in nature and at the same time might...

  12. The unnatural racial naturalism.

    Science.gov (United States)

    Spencer, Quayshawn

    2014-06-01

    In the recent article, "Against the New Racial Naturalism", Adam Hochman (2013, p. 332) argues that new racial naturalists have been too hasty in their racial interpretation of genetic clustering results of human populations. While Hochman makes a number of good points, the purpose of this paper is to show that Hochman's attack on new racial naturalists is misguided due to his definition of 'racial naturalism'. Thus, I will show that Hochman's critique is merely a consequence of an unnatural interpretation of racial naturalism. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. The mechanization of natural philosophy

    CERN Document Server

    Garber, Daniel

    2014-01-01

    This book reviews the transformation of natural philosophy in the 16th and 17th centuries: description of nature in mathematical terms; comparison of natural phenomena to existing or imaginary machines and the use of mechanical analogies in natural philosophy.

  14. Natural Gas Acquisition Program

    Data.gov (United States)

    General Services Administration — The "NGAP" system is a web based application which serves NGAP GSA users for tracking information details for various natural gas supply chain elements like Agency,...

  15. Vermont Designated Natural Areas

    Data.gov (United States)

    Vermont Center for Geographic Information — Under Natural Areas Law (10 Vermont Statutes Annotated, Chapter 83 � 2607) the FPR commissioner, with the approval of the governor, may designate and set aside areas...

  16. Biomimetics: nature based innovation

    National Research Council Canada - National Science Library

    Bar-Cohen, Yoseph

    2012-01-01

    "Based on the concept that nature offers numerous sources of inspiration for inventions related to mechanisms, materials, processes, and algorithms, this book covers the topic of biomimetics and the inspired innovation...

  17. Natural radioactive phon

    International Nuclear Information System (INIS)

    Birjukovs, V.; Birjukov, P.

    2004-01-01

    The natural radiating phon is determined by radioactive isotopes of elements which time of half-decay is commensurable in due course existence of the Earth, dispersing in rocks, ground, water and air, and also space radiation. (authors)

  18. Natural gas for vehicles

    International Nuclear Information System (INIS)

    Chauveron, S. de

    1996-01-01

    This article presents compressed natural gas for vehicles (CNG), which can provide considerable advantages both as an alternative fuel and as a clean fuel. These assets are not only economic but also technical. The first part deals with what is at stake in developing natural gas as a motor fuel. The first countries to use CNG were those with natural gas resources in their subsoil. Today, with a large number of countries having to cope with growing concern about increasing urban pollution, natural gas is also seen as a clean fuel that can help cut vehicle pollutant emissions dramatically. In the second part a brief technical descriptions is given of CNG stations and vehicles, with the aim of acquainting the reader with some of CNG's specific technical features as compared to gasoline and diesel oil. Here CNG technologies are seen to be very close to the more conventional ones. (author)

  19. Natural gas benefits

    International Nuclear Information System (INIS)

    1999-01-01

    The General Auditor in the Netherlands studied the natural gas policy in the Netherlands, as has been executed in the past decades, in the period 1997-1999. The purpose of the study is to inform the Dutch parliament on the planning and the backgrounds of the natural gas policy and on the policy risks with respect to the benefits for the Dutch State, taking into account the developments in the policy environment. The final conclusion is that the proposed liberalization of the national natural gas market will result in a considerable deprivation of income for the State in case the benefit policy is not adjusted. This report includes a reaction of the Dutch Minister of Economic Affairs and an afterword of the General Auditor. In the appendix an outline is given of the natural gas policy

  20. Web life: Ask Nature

    Science.gov (United States)

    2012-11-01

    Ask Nature is a site devoted to biomimicry, an interdisciplinary field in which practitioners study how animals and plants solve problems, and then use those solutions to develop better human technologies.

  1. Natural gas pricing

    International Nuclear Information System (INIS)

    Freedenthal, C.

    1993-01-01

    Natural gas pricing is the heart and soul of the gas business. Price specifically affects every phase of the industry. Too low a price will result in short supplies as seen in the mid-1970s when natural gas was scarce and in tight supply. To fully understand the pricing of this energy commodity, it is important to understand the total energy picture. In addition, the effect and impact of world and US economies, and economics in general are crucial to understanding natural gas pricing. The purpose of this presentation will be to show the parameters going into US natural gas pricing including the influence of the many outside industry factors like crude oil and coal pricing, market drivers pushing the gas industry, supply/demand parameters, risk management for buyers and sellers, and other elements involved in pricing analysis

  2. Art, Technology and Nature

    DEFF Research Database (Denmark)

    Since 1900, the connections between art and technology with nature have become increasingly inextricable. Through a selection of innovative readings by international scholars, this book presents the first investigation of the intersections between art, technology and nature in post-medieval times....... Transdisciplinary in approach, this volume’s 14 essays explore art, technology and nature’s shifting constellations that are discernible at the micro level and as part of a larger chronological pattern. Included are subjects ranging from Renaissance wooden dolls, science in the Italian art academies, and artisanal...... Camilla Skovbjerg Paldam and Jacob Wamberg trace the Kantian heritage of radically separating art and technology, and inserting both at a distance to nature, suggesting this was a transient chapter in history. Thus, they argue, the present renegotiation between art, technology and nature is reminiscent...

  3. Nature as Dissonant Heritage

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    -evident. But who define and decide what kind of nature to restore? And is nature restoration not a contradiction in terms in our deeply cultivated landscapes? To examine these questions it makes sense to draw parallels between nature restoration and the concept of ‘dissonant heritage’ (Ashworth 2010), which...... concerns situations of mismatch between people and their heritage. The aim of the paper is to uncover the latent cultural dissonance in relation to nature restoration and to explain how landscape architecture could play an important role in the management of this dissonance. If one accepts that heritage...... is not the same as history, but a contemporary product shaped from history, it is clear that the same area or object could be part of different heritages, creates by different groups of people for different reasons. Heritance logically and potentially involves disinheritance – our heritage is not necessary...

  4. Natural product antifoulants

    Digital Repository Service at National Institute of Oceanography (India)

    Raveendran, T.V.; Mol, V.P.L.

    Natural Product Antifoulants (NPAs) have been proposed as one of the best replacement options for the most successful antifouling agent, tri-n-butyl tin (TBT), which, due to its ecological incompatibility, is currently facing total global ban...

  5. Breast reconstruction - natural tissue

    Science.gov (United States)

    ... After a mastectomy , some women choose to have cosmetic surgery to remake their breast. This type of surgery ... cancer - breast reconstruction with natural tissue Patient Instructions Cosmetic breast surgery - discharge Mastectomy and breast reconstruction - what to ask ...

  6. Solitonic natural orbitals

    Science.gov (United States)

    Cioslowski, Jerzy

    2018-04-01

    The dependence of the natural amplitudes of the harmonium atom in its ground state on the confinement strength ω is thoroughly investigated. A combination of rigorous analysis and extensive, highly accurate numerical calculations reveals the presence of only one positive-valued natural amplitude ("the normal sign pattern") for all ω ≥1/2 . More importantly, it is shown that unusual, weakly occupied natural orbitals (NOs) corresponding to additional positive-valued natural amplitudes emerge upon sufficient weakening of the confinement. These solitonic NOs, whose shapes remain almost invariant as their radial positions drift toward infinity upon the critical values of ω being approached from below, exhibit strong radial localization. Their asymptotic properties are extracted from the numerical data and their relevance to calculations on fully Coulombic systems is discussed.

  7. Historic Natural Vegetation

    Data.gov (United States)

    California Natural Resource Agency — In 2001, the US Fish and Wildlife Service (USFWS) and the U.S. Bureau of Reclamation (BOR) contracted with the California State University, Chico Research Foundation...

  8. Natural Gas Liquid Pipelines

    Data.gov (United States)

    Department of Homeland Security — Natural gas interstate and intrastate pipelines in the United States. Based on a variety of sources with varying scales and levels of accuracy and therefore accuracy...

  9. Is image steganography natural?

    Science.gov (United States)

    Martín, Alvaro; Sapiro, Guillermo; Seroussi, Gadiel

    2005-12-01

    Steganography is the art of secret communication. Its purpose is to hide the presence of information, using, for example, images as covers. We experimentally investigate if stego-images, bearing a secret message, are statistically "natural." For this purpose, we use recent results on the statistics of natural images and investigate the effect of some popular steganography techniques. We found that these fundamental statistics of natural images are, in fact, generally altered by the hidden "nonnatural" information. Frequently, the change is consistently biased in a given direction. However, for the class of natural images considered, the change generally falls within the intrinsic variability of the statistics, and, thus, does not allow for reliable detection, unless knowledge of the data hiding process is taken into account. In the latter case, significant levels of detection are demonstrated.

  10. Natural Hazards Image Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Photographs and other visual media provide valuable pre- and post-event data for natural hazards. Research, mitigation, and forecasting rely on visual data for...

  11. Natural gas supplies

    International Nuclear Information System (INIS)

    2009-10-01

    This article comments data about the share of natural gas in the energy demand in Europe, about the uses of natural gas by different sectors (housing and office buildings, electricity production, and industry) in Europe, and about gas European imports and about gas supply origins. Graphs are displaying the evolution of energy demand in some European countries between 1990 and 2006 and for different energy sources (natural gas, coal, oil, primary energy, and renewable energies), the evolution of gas production and consumption in different countries of the European Union between 1990 and 2006, and gas import origins in the European Union in 2006. Gas pipeline projects between gas producing countries and Europe are briefly presented, and the development of liquefied natural gas is briefly commented and outlined as a contribution to supply diversification

  12. Natural Gas Market Hubs

    Data.gov (United States)

    Department of Homeland Security — A hub is a physical transfer point for natural gas where several pipelines are connected. A market center is a hub where the operator offers services that facilitate...

  13. Radon - natural health threat

    International Nuclear Information System (INIS)

    Wrixon, Anthony

    1985-01-01

    Natural sources of radiation attract little attention, yet a survey has found radon gas in buildings at levels which put the occupants at some risk. The author wants safety standards set without undue delay. (author)

  14. Are Emotions Natural Kinds?

    Science.gov (United States)

    Barrett, Lisa Feldman

    2006-03-01

    Laypeople and scientists alike believe that they know anger, or sadness, or fear, when they see it. These emotions and a few others are presumed to have specific causal mechanisms in the brain and properties that are observable (on the face, in the voice, in the body, or in experience)-that is, they are assumed to be natural kinds. If a given emotion is a natural kind and can be identified objectively, then it is possible to make discoveries about that emotion. Indeed, the scientific study of emotion is founded on this assumption. In this article, I review the accumulating empirical evidence that is inconsistent with the view that there are kinds of emotion with boundaries that are carved in nature. I then consider what moving beyond a natural-kind view might mean for the scientific understanding of emotion. © 2006 Association for Psychological Science.

  15. More natural gas

    International Nuclear Information System (INIS)

    Leprince, P.; Valais, M.

    1993-01-01

    This paper reports that large resources and growing markets are the salient prospects of natural gas for the coming decades. The greater impact of natural gas on the worldwide energy market can become a reality if several scientific disciplines can be mobilized in order to succeed in cutting production costs. Modeling, mechanics of complex fluids, and physical chemistry of interfaces are basic disciplines for understanding and mastering the gas processing technologies

  16. Lesson "Balance in Nature

    Science.gov (United States)

    Chapanova, V.

    2012-04-01

    Lesson "Balance in Nature" This simulation game-lesson (Balance in Nature) gives an opportunity for the students to show creativity, work independently, and to create models and ideas. It creates future-oriented thought connected to their experience, allowing them to propose solutions for global problems and personal responsibility for their activities. The class is divided in two teams. Each team chooses questions. 1. Question: Pollution in the environment. 2. Question: Care for nature and climate. The teams work on the chosen tasks. They make drafts, notes and formulate their solutions on small pieces of paper, explaining the impact on nature and society. They express their points of view using many different opinions. This generates alternative thoughts and results in creative solutions. With the new knowledge and positive behaviour defined, everybody realizes that they can do something positive towards nature and climate problems and the importance of individuals for solving global problems is evident. Our main goal is to recover the ecological balance, and everybody explains his or her own well-grounded opinions. In this work process the students obtain knowledge, skills and more responsible behaviour. This process, based on his or her own experience, dialogue and teamwork, helps the participant's self-development. Making the model "human↔ nature" expresses how human activities impact the natural Earth and how these impacts in turn affect society. Taking personal responsibility, we can reduce global warming and help the Earth. By helping nature we help ourselves. Teacher: Veselina Boycheva-Chapanova " Saint Patriarch Evtimii" Scholl Str. "Ivan Vazov"-19 Plovdiv Bulgaria

  17. Natural gas supplies

    International Nuclear Information System (INIS)

    2009-01-01

    After having briefly commented the share of natural gas in the primary consumed energy in Europe and in France, and the reasons for its evolution, this document highlights that gas is mainly used for heating, electricity production and industrial purposes, that Europe possesses limited gas resources and must therefore rely on importations. It comments the diversification of supply sources, evokes new gas-pipeline projects between Europe and producer countries (mainly Russia), and briefly comments the development of liquefied natural gas

  18. Natural Hazards, Second Edition

    Science.gov (United States)

    Rouhban, Badaoui

    Natural disaster loss is on the rise, and the vulnerability of the human and physical environment to the violent forces of nature is increasing. In many parts of the world, disasters caused by natural hazards such as earthquakes, floods, landslides, drought, wildfires, intense windstorms, tsunami, and volcanic eruptions have caused the loss of human lives, injury, homelessness, and the destruction of economic and social infrastructure. Over the last few years, there has been an increase in the occurrence, severity, and intensity of disasters, culminating with the devastating tsunami of 26 December 2004 in South East Asia.Natural hazards are often unexpected or uncontrollable natural events of varying magnitude. Understanding their mechanisms and assessing their distribution in time and space are necessary for refining risk mitigation measures. This second edition of Natural Hazards, (following a first edition published in 1991 by Cambridge University Press), written by Edward Bryant, associate dean of science at Wollongong University, Australia, grapples with this crucial issue, aspects of hazard prediction, and other issues. The book presents a comprehensive analysis of different categories of hazards of climatic and geological origin.

  19. The system of nature

    CERN Document Server

    D'Holbac, Baron

    1999-01-01

    "The source of Man's unhappiness is his ignorance of Nature."D'Holbach believed that the misery he saw in mankind around him was caused by religion and its superstitious beliefs - that there was a God who controlled destiny and would reward or punish individuals. The System of Nature was written to replace these delusions with a schema of understanding based solely on the physical workings of nature. "Let Man study this nature, let him learn her laws, contemplate her energies." For d'Holbach the soul is only the physical body, understood from a certain point of view, which dies when the body dies. All the events and the nature of the world can be understood in terms of the motion and properties of matter; even the tiniest causes contribute to huge events - a simple change in the diet of an Emperor (or some other such insignificant cause), he suggests might have been capable of "saving kingdoms." For him, nature's laws are fixed and necessary, and if Man wants to find happiness it is best to accept this - if g...

  20. Natural Resource Management Plan

    Energy Technology Data Exchange (ETDEWEB)

    Green, T. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Schwager, K. [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2016-10-01

    This comprehensive Natural Resource Management Plan (NRMP) for Brookhaven National Laboratory (BNL) was built on the successful foundation of the Wildlife Management Plan for BNL, which it replaces. This update to the 2003 plan continues to build on successes and efforts to better understand the ecosystems and natural resources found on the BNL site. The plan establishes the basis for managing the varied natural resources located on the 5,265-acre BNL site, setting goals and actions to achieve those goals. The planning of this document is based on the knowledge and expertise gained over the past 15 years by the Natural Resources management staff at BNL in concert with local natural resource agencies including the New York State Department of Environmental Conservation, Long Island Pine Barrens Joint Planning and Policy Commission, The Nature Conservancy, and others. The development of this plan works toward sound ecological management that not only benefits BNL’s ecosystems but also benefits the greater Pine Barrens habitats in which BNL is situated. This plan applies equally to the Upton Ecological and Research Reserve (Upton Reserve). Any difference in management between the larger BNL area and the Upton Reserve are noted in the text.

  1. Blackouts and natural risks

    Science.gov (United States)

    Danihelka, P.; Paldusová, E.; Dobeš, P.

    2009-04-01

    "Blackout" has become the common definition for the situation when electricity supply and demand are not balanced and security of supply fails. These failures have many impacts besides the lights going out, but this term is used commonly. Blackouts have drastic impacts for the society on whole and its citizens and some of them can influence big areas and last for long period, so the consequences are catastrophic. Even if at the European scale, the large extend blackouts are supposed to be exceptional, real frequency is relatively high, approximately once per two years. According to statistics, blackouts are often caused by natural causes, especially lightning. An example of lightning caused blackout is New York blackout 1977, leading to the stand-by of nuclear power plant Indian Point and with overall cost more than 300 mil. USD. There is a clear a distinction between those blackouts caused by nature and those that were caused by other faults. Usually, the nature-caused disturbances as Canada 1988, Sweden 2005 and France 1999, stay inside one country. However, their duration can extend to several weeks, and thus the costs of the interruptions and social impacts are high. Blackouts of only technologic and/or anthropogenic origin are frequently shorter, but may concern more end-users, when cascading from one country to another. Lightning is not the only natural event causing blackouts. Eighteen various case studies of blackout caused by natural events different then lightning were studied and following natural phenomenon found as a root causes: 1x forest fire, 1x snow calamity, 1x ice storm, 1x landslide, 1x high temperature, 1x geomagnetic storm, 2x earthquake, 2x inundation, 2x contact of line with trees, 6x storm (wind, hurricane…). We can conclude, that natural event are frequent cause of blackout of medium or large extend and this phenomena should be studied more in details. This contribution was supported by Ministry of Environment of the Czech Republic.

  2. Natural Dietary Phytosterols.

    Science.gov (United States)

    Racette, Susan B; Lin, Xiaobo; Ma, Lina; Ostlund, Richard E

    2015-01-01

    Most clinical phytosterol studies are performed by adding purified supplements to smaller phytosterol amounts present in the natural diet. However, natural dietary phytosterols themselves may also have important effects on cholesterol metabolism. Epidemiological work using food frequency questionnaires to estimate dietary intake suggest that extremes of normal consumption may be associated with 3-14% changes in LDL cholesterol. Standardized food databases do not have enough phytosterol values to allow calculation of phytosterol intake for individuals outside of specialized studies. Natural diets contain phytosterol amounts ranging from less than 60 mg/2000 kcal to over 500 mg/2000 kcal. Physiological studies in which whole body cholesterol metabolism is investigated show large effects of natural dietary phytosterols on cholesterol absorption efficiency, cholesterol biosynthesis and cholesterol excretion which exceed the magnitude of changes in LDL cholesterol. The dual effects of natural phytosterols on both LDL-C and whole body cholesterol metabolism need to be considered in relating them to potential protection from coronary heart disease risk.

  3. Symmetries in nature

    International Nuclear Information System (INIS)

    Mainzer, K.

    1988-01-01

    Symmetry, disymmetry, chirality etc. are well-known topics in chemistry. But they cannot only be found on the molecular level of matter. Atoms and elementary particles in physics are also characterized by particular symmetry groups. Even living organisms and populations on the macroscopic level have functional properties of symmetry. The whole physical, chemical, and biological evolution seems to be regulated by the emergence of new symmetries and the breaking down of old ones. One is reminded of Heisenberg's famous statement: 'Die letzte Wurzel der Erscheinungen ist also nicht die Materie, sondern das mathematische Gesetz, die Symmetrie, die mathematische Form' (Wandlungen in den Grundlagen der Naturwissenschaften, 1959). Historically the belief in symmetry and simplicity of nature has a long philosophical tradition from the Pythagoreans, Plato and Greek astronomers to Kepler and modern scientists. Today, 'symmetries in nature' is a common topic of mathematics, physics, chemistry, and biology. A lot of Nobel prizes were given in honour of inquiries concerning symmetries in nature. The fascination of symmetries is not only motivated by science, but by art and religion too. Therefore 'symmetris in nature' is an interdisciplinary topic which may help to overcome C.P. Snow's 'Two Cultures' of natural sciences and humanities. (author) 17 refs., 21 figs

  4. Natural gas purchasing

    International Nuclear Information System (INIS)

    Freedenthal, C.

    1993-01-01

    In recent years, natural gas has gained new momentum because of changes in marketing and regulations. The gas industry has always received an inordinate amount of regulatory control starting at the well head where the gas is produced to the consuming burner tip. Regulations have drastically impacted the availability of gas. Changes in the marketing and regulations have made the natural gas market sensitive at the point of production, the well head. Now, with plentiful supply and ease of transportation to bring the gas from the producing fields to the consumer, natural gas markets are taking advantage of the changed conditions. At the same time, new markets are developing to take advantage of the changes. This section shows consumers, especially the energy planners for large buyers of fuel, the advantages, sources and new methods of securing natural gas supplies. Background on how natural gas is produced and marketed are given. This section lists marketing sources, regulatory agencies and information groups available to help buyers and consumers of this important fuel for US industries and residences. 7 figs., 8 tabs

  5. Natural resource damage assessment

    International Nuclear Information System (INIS)

    Seddelmeyer, J.

    1991-01-01

    The assessment and collection of natural resource damages from petroleum and chemical companies unfortunate enough to have injured publicly owned natural resources is perhaps the most rapidly expanding area of environmental liability. The idea of recovering for injury to publicly owned natural resources is an extension of traditional common law tort concepts under which a person who negligently injures another or his property is called upon to compensate the injured party. Normally, once liability has been established, it is a fairly straightforward matter to calculate the various elements of loss, such as the cost to repair or replace damaged property, or medical expenses, and lost income. More difficult questions, such as the amount to be awarded for pain and suffering or emotional distress, are left to the jury, although courts limit the circumstances in which the jury is permitted to award such damages

  6. Natural gas storage

    International Nuclear Information System (INIS)

    Bautz, R.

    2009-01-01

    Storage is an important link in the natural gas supply chain. It is a valuable aid to providing the link between remote sources of production and consumption locations. After a brief recall covering the role of storage this article describes the various options for storing natural gas: saline cavities, aquifers, liquefied gas tanks or artificial cavities. A report follows on the different solutions adopted in Europe and in Switzerland, more particularly that chosen by Gaznat in order to contribute to securing supplies in Western Switzerland. Market deregulation has brought changes to the regulations, which are in turn modifying the rules that were in force until just recently, and new topics are arising, such as strategic reserves and pricing rules for stored natural gas. (author)

  7. Natural photonic crystals

    Science.gov (United States)

    Vigneron, Jean Pol; Simonis, Priscilla

    2012-10-01

    Photonic structures appeared in nature several hundred millions years ago. In the living world, color is used for communication and this important function strongly impacts the individual chances of survival as well as the chances to reproduce. This has a statistical influence on species populations. Therefore, because they are involved in evolution, natural color-generating structures are - from some point of view - highly optimized. In this short review, a survey is presented of the development of natural photonic crystal-type structures occurring in insects, spiders, birds, fishes and other marine animals, in plants and more, from the standpoint of light-waves propagation. One-, two-, and three-dimensional structures will be reviewed with selected examples.

  8. Hauntings of Human Nature

    DEFF Research Database (Denmark)

    Clasen, Mathias

    2017-01-01

    The central conflicts of Stephen King’s horror novel The Shining are rooted in human nature and reflect evolutionarily recurrent adaptive problems—the problem of balancing conflicting evolved motives, such as motives for selfish status striving versus motives for affiliative nurturing behavior...... the psychological underpinnings of the novel and the crucial function of the supernatural elements in the meaning structure of the novel. Hence we need an evolutionary psychological perspective which builds on recent findings in the sciences of human nature to account for the novel’s meaning, effects, and continued......, and the problem of surviving the hostile forces of nature. Moreover, the supernatural elements of the novel resonate with evolved intuitions about non-material, moral forces at work in the world. That is why the novel continues to engage readers worldwide. Most critics, however, have overlooked or distorted...

  9. nature in the city

    Directory of Open Access Journals (Sweden)

    Elena Grigoryeva

    2016-08-01

    The object of the issue is a wonderful museum on the Kulikovo Field designed by Sergey Gnedovsky. The unusual architecture of the new museum makes it akin to the earth’s tectonic fault caused by an intolerable tension in expectation of the battle (pp. 113-123. Oleg Yavein and Ilya Lezhava bring us back to the classic of the 20th century Mies van der Rohe and his unique dialogue with nature (pp. 162-175. Relationship between architecture and nature is a rich and limitless theme, like both of these substances. That is why the new Project Baikal issue contains, as usual, more questions than answers. Such is the nature of our journal.

  10. Down with natural selection?

    Science.gov (United States)

    Pigliucci, Massimo

    2009-01-01

    Biologists are increasingly reexamining the conceptual structure of evolutionary theory, which dates back to the so-called Modern Synthesis of the 1930s and 1940s. Calls for an Extended Evolutionary Synthesis (EES) cite a number of empirical and theoretical advances that need to be accounted for, including evolvability, evolutionary novelties, capacitors of phenotypic evolution, developmental plasticity, and phenotypic attractors. In Biological Emergences, however, Robert Reid outlines a theory of evolution in which natural selection plays no role or-worse-actually impedes evolution by what Reid calls "natural experimentation." For Reid, biological complexity emerges because of intrinsic mechanisms that work in opposition to natural selection, a view that would reopen old questions of orthogenesis and Lamarckism. This review outlines why we do need an EES, but also why it is unlikely to take the shape that Reid advocates.

  11. Nature/culture/seawater.

    Science.gov (United States)

    Helmreich, Stefan

    2011-01-01

    Seawater has occupied an ambiguous place in anthropological categories of "nature" and "culture." Seawater as nature appears as potentiality of form and uncontainable flux; it moves faster than culture - with culture frequently figured through land-based metaphors - even as culture seeks to channel water's (nature's) flow. Seawater as culture manifests as a medium of pleasure, sustenance, travel, disaster. I argue that, although seawater's qualities in early anthropology were portrayed impressionistically, today technical, scientific descriptions of water's form prevail. For example, processes of globalization - which may also be called "oceanization" - are often described as "currents," "flows," and "circulations." Examining sea-set ethnography, maritime anthropologies, and contemporary social theory, I propose that seawater has operated as a “theory machine” for generating insights about human cultural organization. I develop this argument with ethnography from the Sargasso Sea and in the Sea Islands. I conclude with a critique of appeals to water's form in social theory.

  12. Knowledge and Natural Resources

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Justinussen, Jens Christian Svabo

    2016-01-01

    Arctic economies are generally natural resource based economies, whether they are indigenous economies largely dependent on living on the land or industrialized economies depending on marine resources, mineral resources or fossil or renewable energy resources. However, the central role of knowledge...... for Arctic communities to secure local benefits and achieve sustainable development around their natural resources is often overlooked in the literature. This chapter will look at the knowledge-natural resources link for local benefits and sustainable Arctic development. For doing so, the chapter will focus...... on the Icelandic and Faroese experiences with marine resources and renewable energy resources in geothermal, hydro, tidal and wind power. Iceland and the Faroe Islands are selected because they are examples of very small Arctic societies, which particularly well illustrate how the combination of human capital...

  13. Natural gas's hottest spot

    International Nuclear Information System (INIS)

    Peterson, T.

    1993-01-01

    This paper reviews the growing power and economic strength of Enron Corp., a natural gas distributor and exploration company. The paper reviews the policy of the company to exploit deregulation at home and privatization of all sorts of energy companies abroad. Enron is actively building its own power plants in the US and has successfully boosted their profits by 20 percent in what was considered a flat natural gas market. The paper goes on to discuss the company's view of the new energy tax and how it should benefit natural gas companies as a whole. Finally the paper reviews the contracting procedures of the company to secure long-term fixed price contracts in a volatile market which precludes most companies from taking the risk

  14. Canadian natural gas

    International Nuclear Information System (INIS)

    Lucas, D.A.

    1991-01-01

    Canada's natural gas industry enjoys a quiet confidence as it looks ahead to the 1990s. In this paper, the author explains why, despite some critical uncertainties, the optimism endures. Reviewing the current conditions of supply, production, consumption, pipelines, and pipeline expansion plans, the author contends that the New World of the 1990s will belong to natural gas. The author's assessment of natural gas markets proceeds far beyond the borders of Canada. The author examines the determinants of gas prices throughout North America and he identifies the one force that promises to seize almost complete control of gas prices throughout the continent. While the analysis points out the attributes of this new pricing regime, it also names the obstacles that could prevent this emerging mechanism from assuming its anticipated position

  15. Natural products in endodontics.

    Science.gov (United States)

    Almadi, Ebtissam M; Almohaimede, Amal A

    2018-02-01

    Herbal remedies are used throughout the world, either in earlier or in recent times. The number of studies on this alternative therapeutic system increased in the last decades. In this paper, the relevant literature on the use of natural products in root canal therapy is revised from a MEDLINE database search. The uses of medicinal plants in endodontics include cleaning and disinfection of root canals, intracanal medicaments between appointments, sealer cements, and for removal of obturation material. Other studies showed the effect of natural products in pulpal and dentin repair. Their use is anecdotal, and their effectiveness showed to be variable and is always compared to the chemical standards currently being used. Alkaloids, coumarins, saponins, and flavonoids are aromatic substances that are produced by plants and evaluated for their therapeutic potential. Further investigation into benefits of natural products is warranted.

  16. Natural Selection and Morality

    Directory of Open Access Journals (Sweden)

    Alejandro Rosas

    2006-12-01

    Full Text Available Resumen:En este ensayo abordo los intentos, relativamente recientes, de dar una explicación de la moralidad como adaptación por selección natural. Mi exposición tiene una introducción y cuatro partes: en la primera explico en qué consiste la paradoja del altruismo biológico. En la segunda expongo la solución que apela a la selección de grupos, recientemente resurgida; la solución que presuntamente aplicó Charles Darwin cuando formuló sus reflexiones biológicas sobre la moralidad humana. En la tercera expongo la solución sociobiológica, que opta por negar que la selección natural pueda explicar directamente la moralidad humana. La moralidad se presenta más bien como opuesta a la naturaleza diseñada por selección natural. En la cuarta parte desarrollo brevemente una explicación de la moralidad como adaptación que beneficia a los individuos. No opone la moralidad a la naturaleza, ni apela a la selección de grupos. Se sirve de un mecanismo de selección que opera a través de preferencias en la interacción social.Abstract:In this essay, I address recent attempts to account for morality as an adaptation due to natural selection. After a brief introduction, my exposition has four sections. I first explain the paradox of biological altruism. Second, I explain the solution to the paradox in terms of group selection. This solution was presumably applied by Darwin himself as he discussed human morality, and it has experienced a recent revival, though it remains suspicious to most biologists. In the third section I offer a socio-biological solution that opts for denying that morality can be explained by any form of natural selection. Morality is opposed to human nature as designed by natural selection. In the fourth, I argue for an explanation in terms of individual selection. It does not oppose morality to nature, and does not need the workings of group selection; rather, it operates through the agents’ psychological preferences

  17. MENOPAUSE AND NATURAL HEALING

    Directory of Open Access Journals (Sweden)

    Lucija Vrabič Dežman

    2008-12-01

    The studies could not decisively confirm the effectiveness of various phytoestrogens inamelioration of climacteric symptoms. Most studies have proven the effectiveness of thenatural medication made of Cimicifuga racemosa and its safe short-term use. Gynecologists should be familiar with the basics of phytotherapy and the results of clinical studiesin this field in order to confidently advise women to use the natural medications in caseswhere despite the climacteric symptoms they cannot or will not use HRT, consequentlygreatly reducing the quality of their lives. In cases where climacteric symptoms are mild tomoderate, some menopausal societies around the globe suggest trying natural medicationfirst, and only later implementing HRT

  18. The natural gas market

    International Nuclear Information System (INIS)

    Lagrasta, F.; Kaminski, V.; Prevatt, R.

    1999-01-01

    This chapter presents a brief history of the natural gas market highlighting the changes in the gas market and examining risk management in practice detailing the types of price risks, and the use of hedging using forwards and swaps. Options to manage risk are identified, and the role of risk management in financing, the role of the intermediary, and the market outlook are discussed. Panels describing the market structure, storage and natural gas risk management, the art of risk management, the winter 1995-96 basis blowout, spark spreads, the UK gas market and Europe, and weather derivatives are presented

  19. Natures of Conduct

    DEFF Research Database (Denmark)

    Sielemann, Rasmus Basse

    Natures of Conduct explores the rationalities, practices and techniques of government processes in the Danish West Indies in the period between the late eighteenth century to the end of Danish colonial rule in 1917. In doing so, it engages Michel Foucault’s concepts of governmentality and the ‘di......Natures of Conduct explores the rationalities, practices and techniques of government processes in the Danish West Indies in the period between the late eighteenth century to the end of Danish colonial rule in 1917. In doing so, it engages Michel Foucault’s concepts of governmentality...

  20. Monitoring natural phytoplankton communities

    DEFF Research Database (Denmark)

    Haraguchi, L.; Jakobsen, H. H.; Lundholm, Nina

    2017-01-01

    -consuming and/or expensive, limiting sampling frequency. The use of faster methods, such as flow cytometry, has become more frequent in phytoplankton studies, although comparisons between this technique and traditional ones are still scarce. This study aimed to assess if natural phytoplankton communities...... carbon biomass with PFCM, applying the same conversion factors as for microscopy. Biomasses obtained with PFCM, estimated from live cells, were higher than microscopy for natural samples. We conclude that PFCM results are comparable to classical techniques, yet the data from PFCM had poor taxonomic...

  1. The natural radiation background

    International Nuclear Information System (INIS)

    Duggleby, J.C.

    1982-01-01

    The components of the natural background radiation and their variations are described. Cosmic radiation is a major contributor to the external dose to the human body whilst naturally-occurring radionuclides of primordial and cosmogenic origin contribute to both the external and internal doses, with the primordial radionuclides being the major contributor in both cases. Man has continually modified the radiation dose to which he has been subjected. The two traditional methods of measuring background radiation, ionisation chamber measurements and scintillation counting, are looked at and the prospect of using thermoluminescent dosimetry is considered

  2. Reducing natural disaster vulnerability

    Science.gov (United States)

    Zielinski, Sarah

    2006-04-01

    Because poor countries are vulnerable to the impact of natural disasters, the U.K. Department for International Development (DFID) launched on 30 March a new policy to better integrate natural disaster risk reduction into development and humanitarian activities. Gareth Thomas, U.K. development minister, said, ``There is nothing we can do to stop hurricanes, tsunamis, and earthquakes from striking. But what we can do is help put simple measures in place, such as better built houses, schools, and hospitals alongside more high-tech early warning systems to reduce the loss of life.''

  3. Training and natural immunity

    DEFF Research Database (Denmark)

    Pedersen, Bente Klarlund; Helge, Jørn Wulff; Richter, Erik

    2000-01-01

    these subjects were used to eliminate day-to-day variation in the immunological tests. Independently of diet, training increased the percentage of CD3-CD16+ CD56+ natural killer (NK) cells from [mean (SEM)] 14 (1) % to 20 (3) % (P = 0.05), whereas the NK-cell activity, either unstimulated or stimulated...... influence natural immunity, and suggest that ingestion of a fat-rich diet during training is detrimental to the immune system compared to the effect of a carbohydrate-rich diet....

  4. Nature of Human Rights

    Directory of Open Access Journals (Sweden)

    Carlos López Dawson

    2016-07-01

    Full Text Available In the formation of a new Constitution the constituents will require to know or reach an agreement on the nature of human rights; then, to determine how the State will enforce the respect to those rights. To do so, it is necessary to resort to the history and evolution of these rights, and the present work aims to contribute to an efficient productive debate about the nature of human rights, so that citizens can decide on the understanding that this is a thoughtful democratic and humanistic founded decision. The analysis is in the actual technical-ideological republican system which correspond to the current state of international law

  5. Battles Fought in Nature

    DEFF Research Database (Denmark)

    Poulsen, Dorthe Varning; Stigsdottir, Ulrika S.

    2015-01-01

    Using horticultural activities and nature experiences to aid the recovery of returning soldiers has a long history. An increasing number of practical experiences and a few research studies confirm the fact that it may well be beneficial. A review by Varning Poulsen et al. (Under review) describes...... the contradiction between the large number of programs using nature-based therapy to treat veterans with Post Traumatic Stress Disorder (PTSD) and the small amount of scientific studies in the field. In order to increase knowledge in this field, a project was initiated in Denmark. The overall aim of the project was...

  6. Natural language modeling

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, J.K. [Sandia National Labs., Albuquerque, NM (United States)

    1997-11-01

    This seminar describes a process and methodology that uses structured natural language to enable the construction of precise information requirements directly from users, experts, and managers. The main focus of this natural language approach is to create the precise information requirements and to do it in such a way that the business and technical experts are fully accountable for the results. These requirements can then be implemented using appropriate tools and technology. This requirement set is also a universal learning tool because it has all of the knowledge that is needed to understand a particular process (e.g., expense vouchers, project management, budget reviews, tax, laws, machine function).

  7. Structural patterns in nature

    DEFF Research Database (Denmark)

    Wester, Ture

    2004-01-01

    It seems that some very basic randomly produced geometric/topological patterns are commonly found in Nature and have often very distinctive structural qualities. In nature we find the same pattern in all scales from the universe to molecules, from solar systems to packing of cells, from glaciers...... be an inspiration to structural morphologists and other dealing with the shaping of structures for buildings and other objects. Often the patterns appear in "dual" materializations, which indicate two radically different structural types of action. Randomness as a generator for optimal and basic structural action...

  8. Structural patterns in nature

    DEFF Research Database (Denmark)

    Wester, Ture

    2003-01-01

    It seemens that some very basic randomly produced geometric/topological patterns are commonly found in Nature and have often very distinctive structural qualities. In Nature we find the same pattern in all scales from the universe to molecules, from solar systems to packing of cells, from glaciers...... be an inspiration to structural morphologists and other dealing with the shaping of structures for buildings and other objects. Often the patterns appear in "dual" materializations, which indicate two radically different structural types of action. Randomness as a generator for optimal and basic structural action...

  9. Enhance Nature Exploration with Technology

    Science.gov (United States)

    Holloway, Patricia; Mahan, Carol

    2012-01-01

    Kids and nature seem like a natural combination, but what was natural a generation ago is different today. Children are spending less time outdoors but continue to need nature for their physical, emotional, and mental development. This fact has led author Richard Louv to suggest that today's children are suffering from "nature-deficit disorder"…

  10. AT THE WHIM OF NATURE "NATURAL DISASTERS": CAUSES AND PREVENTION

    OpenAIRE

    Akhand Pratibha; Akhand Archna

    2017-01-01

    This paper seeks to determine the natural disasters, causes and effects on environment. Natural disasters are any catastrophic event that is caused by nature or the natural processes of the earth. It could be related to weather, geology, biology or even factors outside the Earth. Examples are earthquakes, hurricanes, droughts and flooding. Nature is bountiful full of resources used by the living organisms use for their survival and well-being. But nature has its own control systems. Resources...

  11. Nature as Inspiration

    Science.gov (United States)

    Tank, Kristina; Moore, Tamara; Strnat, Meg

    2015-01-01

    This article describes the final lesson within a seven-day STEM and literacy unit that is part of the Picture STEM curriculum (pictureSTEM. org) and uses engineering to integrate science and mathematics learning in a meaningful way (Tank and Moore 2013). For this engineering challenge, students used nature as a source of inspiration for designs to…

  12. THE NATURE OF COMPREHENSION.

    Science.gov (United States)

    CLELAND, DONALD L.

    THE NATURE OF COMPREHENSION IS DEFINED AND CLARIFIED. THE LITERATURE IS SURVEYED TO SHOW THAT THE DEVELOPMENT OF CONCEPTS IS IMPORTANT IN INTELLECTUAL ACTIVITIES. IT IS POINTED OUT THAT CONCEPTS ARE BUILT FROM PERCEPTS, IMAGES, SENSATION, AND MEMORIES, AND THAT THE STEPS WHICH ARE EMPLOYED AS CONCEPTS ARE BUILT AND REFINED AND INCLUDE PERCEIVING,…

  13. Livelihoods and natural resources

    DEFF Research Database (Denmark)

    Cotta, Jamie Nicole

    This dissertation research contributes to the emerging body of knowledge on the economic contributions of natural resources to rural livelihoods, including their role in household shock coping, in the humid tropics. Data from one of the first comprehensive household income quantifications...

  14. Nature in motion

    NARCIS (Netherlands)

    Drenthen, M.; Keulartz, F.W.J.; Proctor, J.

    2009-01-01

    As Raymond Williams (1983) famously declared, nature is one of the most complex words in the English language – and, we may confidently predict, its Germanic relatives including Dutch. The workshop that took place in June 2007 in the Netherlands, from which this volume is derived, was based on an

  15. Saving Natural Inflation

    Energy Technology Data Exchange (ETDEWEB)

    Croon, Djuna; Sanz, Verónica, E-mail: d.croon@sussex.ac.uk, E-mail: v.sanz@sussex.ac.uk [Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom)

    2015-02-01

    Slow-roll inflation requires the inflaton field to have an exceptionally flat potential, which combined with measurements of the scale of inflation demands some degree of fine-tuning. Alternatively, the flatness of the potential could be due to the inflaton's origin as a pseudo-Goldstone boson, as in Natural Inflation. Alas, consistency with Planck data places the original proposal of Natural Inflation in a tight spot, as it requires a trans-Planckian excursion of the inflaton. Although one can still tune the renormalizable potential to sub-Planckian values, higher order corrections from quantum gravity or sources of breaking of the Goldstone symmetry would ruin the predictivity of the model. In this paper we show how in more realistic models of Natural Inflation one could achieve inflation without a trans-Planckian excursion of the field. We show how a variant of Extra-natural inflation with bulk fermions can achieve the desired goal and discuss its four-dimensional duals. We also present a new type of four dimensional models inspired in Little Higgs and Composite Higgs models which can lead to sub-Planckian values of the inflaton field.

  16. Nature Identical Prosody

    DEFF Research Database (Denmark)

    Juel Henrichsen, Peter

    2012-01-01

    ; such as low naturalness (DiSyn) and dependence on huge amounts of background data (UnitSyn). We present a hybrid model based on high-level speech data. As preliminary tests show, prosodic models combining DiSyn style at the phone level with UnitSyn style at the supra-segmental levels may approach Unit...

  17. Bosbus; mobile nature reserve

    NARCIS (Netherlands)

    Matton, T.; Kuypers, V.H.M.; Timmermans, W.

    2004-01-01

    Nature has discovered the global village. Over the years, hundreds of exotic plants and animals have made their way into the Netherlands. They take advantage of the existing urban infrastructure to seek out suitable niches in the city. People rarely think of these urban ecosystems in terms of

  18. Cultivating human nature

    NARCIS (Netherlands)

    Derksen, Maarten

    2007-01-01

    Evolutionary psychology claims to offer a unified perspective on human nature and culture, which can serve to further the integration of psychology and the social sciences. I describe four approaches to evolutionary psychology, and note increasing attention to the agency of the individual in

  19. Managing natural resources

    International Development Research Centre (IDRC) Digital Library (Canada)

    The balance between these two is a key issue in many developing ... that results when trees are cut to make fuel. New bamboo-based ... Improvement Center and the Mexican natural resources agency INIFAP can- vassed farmers and catalogued the attrib- utes of preferred varieties. These were then “frozen in time” in ...

  20. Surfaces with Natural Ridges

    DEFF Research Database (Denmark)

    Brander, David; Markvorsen, Steen

    2015-01-01

    We discuss surfaces with singularities, both in mathematics and in the real world. For many types of mathematical surface, singularities are natural and can be regarded as part of the surface. The most emblematic example is that of surfaces of constant negative Gauss curvature, all of which neces...