Fetal small bowel volvulus without malrotation: the whirlpool & coffee bean signs.

PubMed

Jakhere, S G; Saifi, S A; Ranwaka, A A

2014-01-01

Intestinal volvulus is a common condition seen in infancy and adulthood, but small bowel volvulus is a rare condition affecting the fetus in utero. Very few cases have been reported describing the ultrasound findings of the same. We present a case report of a case of intestinal volvulus which was diagnosed prenatally based on the ultrasound features of whirlpool sign and coffee bean sign. An emergency caesarian section was performed, small bowel volvulus was confirmed on post-natal ultrasound, and the neonate was subsequently operated. Although these signs have been separately described previously in the literature, in our case both these signs were seen in the same patient. Our case is a rare presentation with the occurrence of volvulus without malrotation, the contrary being more common.

Volvulus of the small intestine associated with left paraduodenal hernia: a case report.

PubMed

Ghorbel, Soufiene; Chouikh, Taieb; Chariag, Awatef; Nouira, Faouzi; Khemakhem, Rachid; Jlidi, Said; Chaouachi, Beji

2011-02-01

To report a rare case of a left paraduodenal hernia presenting as volvulus of the small intestine associated to an intestinal malrotation. A 2 months-old girl presented with history of bilious vomiting, sonography showed signs of volvulus and emergency laparotomy was performed and confirmed left paraduodenal hernia containing a part of the ileon, coecum with right colon and volvulus of the small intestine out of the hernia sac. Paraduodenal hernia is an uncommon cause of small bowel volvulus. It can be suspected by clinical and radiological findings, surgery is always required to prevent small bowel necrosis and to repair the defect.

Chronic gastric instability and presumed incomplete volvulus in dogs.

PubMed

Paris, J K; Yool, D A; Reed, N; Ridyard, A E; Chandler, M L; Simpson, J W

2011-12-01

Chronic gastric volvulus in dogs results in long-standing gastrointestinal signs unlike those of acute gastric dilatation and volvulus. This report describes chronic gastric volvulus in seven dogs. The majority of dogs presented with weight loss, chronic vomiting, lethargy and abdominal pain. A combination of radiographic, ultrasonographic and endoscopic imaging indicated altered positioning of gastric landmarks. Dynamic changes were identified in some cases. Exploratory coeliotomy and surgical gastropexy were performed in all dogs. Clinical signs improved or resolved in six of seven dogs postoperatively. Chronic gastric volvulus is an uncommon condition in dogs, but should be considered as a differential in cases presenting with the above clinical signs. © 2011 British Small Animal Veterinary Association.

Neonatal sigmoid volvulus.

PubMed

Khalayleh, Harbi; Koplewitz, Benjamin Z; Kapuller, Vadim; Armon, Yaron; Abu-Leil, Sinan; Arbell, Dan

2016-11-01

Neonatal sigmoid volvulus is a rare entity. It is associated with Hirschsprung's disease. Presentation is acute abdominal distention, vomiting and obstipation. Abdominal radiograph will show the "coffee bean" sign, but this is frequently missed and the diagnosis requires a high index of suspicion. Treatment options include contrast enema, colonoscopy or laparotomy, depending on the condition of the baby and local availability. During the last 6years, 6 infants with sigmoid volvulus were treated in our department. Four presented during the first 48h since birth, and 2 presented at the age of 2 and 7weeks of age. One child was operated and 5 had primary contrast enema with radiologic de-volvulus. Rectal biopsy was performed in all cases; three children had Hirschsprung's disease. Those with normal biopsies responded well to rectal washouts. Two patients had early one stage transanal pullthrough and one had 2 further occasions of sigmoid volvulus prior to definitive surgery. All three recovered with an uneventful course. Neonatal sigmoid volvulus requires a high level of suspicion. Contrast enema is efficient for primary de-volvulus. Rectal biopsy should be performed and if positive for Hirschsprung's disease, surgery should be performed sooner rather than later. Copyright © 2016 Elsevier Inc. All rights reserved.

Caecal volvulus: a consequence of acute cholecystitis

PubMed Central

Anjum, Ghulam Ali; Jaberansari, Sarah; Habeeb, Kayode

2013-01-01

Caecal volvulus is an uncommon cause of closed loop intestinal obstruction which can lead to caecal gangrene and high mortality. Delay in diagnosis is one of the causes of this high mortality. Caecal volvulus is reported to be associated with previous abdominal surgery in most cases. We present the first reported case of caecal volvulus following/associated with acute cholecystitis. PMID:23749828

Diagnosis of pediatric colonic volvulus with abdominal radiography: how good are we?

PubMed

Marine, Megan B; Cooper, Matthew L; Delaney, Lisa R; Jennings, Samuel Gregory; Rescorla, Frederick J; Karmazyn, Boaz

2017-04-01

Colonic volvulus is rare in children and associated with colonic dysmotility. Diagnosis of colonic volvulus on radiographs in these patients can be challenging. The purpose of the study was to identify the accuracy of abdominal radiographs and findings suggestive of colonic volvulus. A retrospective (2003- 2014) study of all children with colonic volvulus proven surgically or endoscopically reviewed their medical charts for underlying disease and clinical presentation as well as their original radiograph reports. Two pediatric radiologists (reader 1 and reader 2) independently reviewed the radiographs. The kappa test was used to evaluate interobserver variability. There were 19 cases of colonic volvulus in 18 patients (11 males) a mean age 14 years. Cecal volvulus was the most common finding at 14/19 cases (74%). Sixteen of 18 (89%) patients had neurological impairment and 10 of 18 (56%) had intestinal dysmotility. The most common presentation was abdominal distension (14/19 [74%]) and pain (11/19 [58%]). Colonic volvulus was diagnosed in only 7/16 (44%) of the abdominal radiographs. The specific finding of a coffee-bean sign was retrospectively observed only by reader 2 in two cases. Absence of rectal gas and focal colonic loop dilation were the most common findings by the readers (average 73.5% and 87%, respectively) with Kappa values of 0.3 and 0.38, respectively. Diagnosis of colonic volvulus in children can be challenging. Radiologists should be alerted to the possibility of colonic volvulus when there is focal colonic loop distention or absent rectal gas.

Laparoscopic management of terminal ileal volvulus caused by Meckel's diverticulum.

PubMed

Xanthis, A; Hakeem, A; Safranek, P

2015-04-01

Complications from a Meckel's diverticulum include diverticulitis, bleeding, intussusception, bowel obstruction, a volvulus, a vesicodiverticular fistula, perforation or very rarely as a tumour. We report a case where a Meckel's diverticulum presented with a terminal ileal volvulus in a 32-year-old man without the presence of a typical vitelline band or axial torsion of the diverticulum causing the volvulus. It was successfully managed laparoscopically.

Spontaneous Acute Mesenteroaxial Gastric Volvulus Diagnosed by Computed Tomography Scan in a Young Man.

PubMed

Jabbour, Gaby; Afifi, Ibrahim; Ellabib, Mohamed; El-Menyar, Ayman; Al-Thani, Hassan

2016-04-26

Acute gastric volvulus is a surgical emergency that requires early recognition and treatment. Acute idiopathic mesenteroaxial gastric volvulus is a rare sub-type and there are few cases reported in children and there are even fewer reports in adults. We report a rare case of a 23-year-old man who presented with a 1-day history of vomiting, epigastric pain, distention, and constipation. The diagnosis for mesenteroaxial type gastric volvulus was confirmed by abdominal radiography and computed tomography. The patient was successfully treated by laparotomy with resection of the ischemic stomach wall and anastomosis. Acute spontaneous mesenteroaxial gastric volvulus is rare in adults and early diagnosis is challenging due to non-specific symptoms. A missed or delayed diagnosis may result in serious complications due to gastric obstruction. A patient presenting with severe epigastric pain and clinical evidence of gastric outlet obstruction should be considered as a surgical emergency to rule out gastric volvulus. High index of suspicion, early diagnosis and prompt surgical management are important for favorable outcome in patients with acute spontaneous gastric volvulus.

Roux limb volvulus in laparoscopic Roux-en-Y gastric bypass due to Roux limb stabilization suture: case series.

PubMed

Marr, Brendan; Yenumula, Panduranga

2012-01-01

Complications after laparoscopic Roux-en-Y gastric bypass surgery may be related to the type of surgical technique employed. One technique, the placement of a Roux limb stabilization suture, presumably prevents kink at the gastrojejunal anastomosis. However, it can have an adverse effect and we studied a series of cases presenting with intestinal obstruction secondary to this stitch. A retrospective review of a prospectively collected database of laparoscopic Roux-en-Y gastric bypass cases who had reoperations for Roux limb volvulus was performed at a single bariatric center by a single surgeon. Out of 199 patients who underwent laparoscopic Roux en Y gastric bypass with placement of Roux limb stabilization suture, 4 patients (2.01%) presented with Roux limb volvulus postoperatively. BMI was 45.35 ± 2.95. The postoperative time to presentation was 11 ± 10.6 months. All four patients required surgical exploration to reduce the volvulus. In all cases, the Roux limb volvulus was directly attributable to the presence of the stabilization suture. In subsequent 250 cases where this suture was eliminated, there was no volvulus of Roux limb seen. The use of a stabilization suture can result in volvulus of the Roux limb causing intestinal obstruction and this complication can be prevented by avoiding this suture.

Successful treatment of small intestinal volvulus in two cats.

PubMed

Knell, Sebastian C; Andreoni, Angelo A; Dennler, Matthias; Venzin, Claudio M

2010-11-01

Mesenteric volvulus describes a torsion of the small intestine around the mesenteric root, which can be partial or complete. In dogs, it is an uncommon condition, with German shepherd dogs showing a predisposition. Chronic mesenteric volvulus has also been described. In cats, previous reports have documented two cases of small intestinal volvulus, both diagnosed at necropsy, and a further case of volvulus of the colon in a patient that died after surgery. This report describes two cats with mesenteric volvulus that were successfully treated. To the authors' knowledge, no reports of antemortem diagnosis or treatment of small intestinal volvulus in cats have previously been published. On the basis of the cases presented, it appears that the diagnosis of intestinal volvulus may be more difficult in cats than in dogs, but that the prognosis may not be as poor. Therefore, it is suggested that owners be encouraged to pursue surgery. Copyright © 2010 ISFM and AAFP. Published by Elsevier Ltd. All rights reserved.

Gastric Volvulus with Segmental Necrosis Treated with Wedge Resection and Gastrogastrostomy.

PubMed

Merz, Alexa Elizabeth; Preston, Jennifer Francis

2017-12-01

Ischemic necrosis is a feared complication of acute gastric volvulus, occurring in 11% of patients presenting with the condition and responsible for mortality in 30%. In such cases, there are few well-validated options for surgical reconstruction. We present the case of a 77-year-old woman with intraabdominal mesenteroaxial gastric volvulus with segmental ischemic gastric necrosis who underwent wedge gastrectomy and hand-sewn gastrogastrostomy. She did well postoperatively and experienced no significant gastrointestinal complications. Gastric wedge resection with gastrogastrostomy presents a novel surgical intervention for a rare and highly morbid entity. We hope to add it to the repertoire of surgeons facing acute gastric volvulus complicated by segmental necrosis.

Wandering Spleen and Organoaxial Gastric Volvulus after Morgagni Hernia Repair: A Case Report and Review of the Literature

PubMed Central

Gulia, Caterina; Miele, Vittorio; Trinci, Margherita; Briganti, Vito

2016-01-01

Wandering spleen and gastric volvulus are two rare entities that have been described in association with congenital diaphragmatic hernia. The diagnosis is difficult and any delay can result in ischemia and necrosis of both organs. We present a case of a 13-year-old girl, previously operated on for anterior diaphragmatic hernia and intrathoracic gastric volvulus, that presented to our service for a subdiaphragmatic gastric volvulus recurrence associated with a wandering spleen. In this report we reviewed the literature, analyzing the clinical presentation, diagnostic assessment, and treatment options of both conditions, in particular in the case associated with diaphragmatic hernia. PMID:27703832

Perinatal Survival of a Fetus with Intestinal Volvulus and Intussusception: A Case Report and Review of the Literature

PubMed Central

Ohuoba, Esohe; Fruhman, Gary; Olutoye, Oluyinka; Zacharias, Nikolaos

2013-01-01

Fetal intestinal volvulus is a rare life-threatening condition. Late diagnosis of volvulus contributes to high rate of morbidity and mortality. It has variable degrees of presentation and survival. Intrauterine volvulus may be complicated by intestinal atresia due to ischemic necrosis. To our knowledge, there are three reported cases of term fetal demise. We report a case of fetal intestinal volvulus with perinatal survival of the largest term infant described with this complication to date. The volvulus was associated with type 3A jejunal atresia and intestinal pathology was noted on prenatal ultrasound. The infant was born via urgent cesarean delivery at 376/7 weeks of gestation and underwent emergent exploratory laparotomy with resection of small bowel and primary end-to-end anastomosis. Intrauterine intestinal volvulus may be suspected on prenatal ultrasound but only definitively diagnosed postnatally. Signs of fetal distress and volvulus are rarely associated with reports of survival in the term fetus. We review reported cases of prenatally suspected volvulus in infants documented to survive past the neonatal period. As fetal volvulus and most intestinal atresias/stenoses manifest during the third trimester, we recommend that the limited fetal anatomical survey during growth ultrasounds at 32 to 36 weeks routinely include an assessment of the fetal bowel. PMID:24147247

Perinatal survival of a fetus with intestinal volvulus and intussusception: a case report and review of the literature.

PubMed

Ohuoba, Esohe; Fruhman, Gary; Olutoye, Oluyinka; Zacharias, Nikolaos

2013-10-01

Fetal intestinal volvulus is a rare life-threatening condition. Late diagnosis of volvulus contributes to high rate of morbidity and mortality. It has variable degrees of presentation and survival. Intrauterine volvulus may be complicated by intestinal atresia due to ischemic necrosis. To our knowledge, there are three reported cases of term fetal demise. We report a case of fetal intestinal volvulus with perinatal survival of the largest term infant described with this complication to date. The volvulus was associated with type 3A jejunal atresia and intestinal pathology was noted on prenatal ultrasound. The infant was born via urgent cesarean delivery at 37(6/7) weeks of gestation and underwent emergent exploratory laparotomy with resection of small bowel and primary end-to-end anastomosis. Intrauterine intestinal volvulus may be suspected on prenatal ultrasound but only definitively diagnosed postnatally. Signs of fetal distress and volvulus are rarely associated with reports of survival in the term fetus. We review reported cases of prenatally suspected volvulus in infants documented to survive past the neonatal period. As fetal volvulus and most intestinal atresias/stenoses manifest during the third trimester, we recommend that the limited fetal anatomical survey during growth ultrasounds at 32 to 36 weeks routinely include an assessment of the fetal bowel.

A unique case of recurrent metachronous volvulus of the gastrointestinal tract.

PubMed

Avgerinos, Dimitrios V; Llaguna, Omar H; Friedman, Richard L

2009-12-01

Colonic volvulus is an uncommon disease that predisposes patients to bowel obstruction in both the adult and pediatric population. The international literature offers few reports of synchronous or metachronous volvulus of 2 organs of the gastrointestinal tract. We describe a unique case of a patient who presented with recurrent metachronous volvulus of the sigmoid colon, cecum, and stomach. The patient underwent multiple operations for bowel obstruction, lysis of adhesions, and colon resection. The interesting intraoperative findings were a very long mesentery and peritoneal attachments of the intraabdominal gastrointestinal organs that made the stomach and colon extremely mobile and thus susceptible to volvulus. Prophylactic pexis of the cecum and the stomach during the first operation, in light of the elongated mesentery, may have prevented the subsequent episodes of volvulus.

Treatment of recurrent sigmoid volvulus in Parkinson's disease by percutaneous endoscopic colostomy

PubMed Central

Toebosch, Susan; Tudyka, Vera; Masclee, Ad; Koek, Ger

2012-01-01

The exact aetiology of sigmoid volvulus in Parkinson's disease (PD) remains unclear. A multiplicity of factors may give rise to decreased gastrointestinal function in PD patients. Early recognition and treatment of constipation in PD patients may alter complications like sigmoid volvulus. Treatment of sigmoid volvulus in PD patients does not differ from other patients and involves endoscopic detorsion. If feasible, secondary sigmoidal resection should be performed. However, if the expected surgical morbidity and mortality is unacceptably high or if the patient refuses surgery, percutaneous endoscopic colostomy (PEC) should be considered. We describe an elderly PD patient who presented with sigmoid volvulus. She was treated conservatively with endoscopic detorsion. Surgery was consistently refused by the patient. After recurrence of the sigmoid volvulus a PEC was placed. PMID:23155325

Gastric volvulus with partial and complete gastric necrosis

PubMed Central

Shukla, Ram Mohan; Mandal, Kartik Chandra; Maitra, Sujay; Ray, Amit; Sarkar, Ruchirendu; Mukhopadhyay, Biswanath; Bhattacharya, Malay

2014-01-01

Here, we report two interesting cases of gastric necrosis in acute gastric volvulus due to eventration of the diaphragm. Both the cases presented with a significant challenge and were managed successfully. The management of the cases is presented and relevant literature is discussed. To the best of our knowledge, this is the first case report of gastric volvulus with gastric necrosis requiring complete and partial gastrectomy in the available English literature. PMID:24604987

Transverse colon volvulus in neurologicaly imparied patient as an emergency surgical condition: A case report.

PubMed

Miličković, Maja; Savić, Đorđe; Stanković, Nikola; Vukadin, Miroslav; Božić, Dejana

2017-01-01

Transverse colon volvulus is an uncommon cause of bowel obstruction in general. Predisposing factors are mental retardation, dysmotility disorders, chronic constipation and congenital megacolon. We presented transverse colon volvulus in a 16-year-old boy with cerebral palsy. Chronic constipation in neurologicaly impaired patient was a risk factor predisposing to volvulus. The patient was admitted to the hospital with enormous abdominal distension and acute respiratory insufficiency. A boy was emergently taken to the operating room for exploratory laparotomy. During the surgery, a 360º clockwise volvulus of the transverse colon was found. After reduction of volvulus, an enormous transverse colon was resected and colostomy was formed. In the postoperative period, despite the good functioning of stoma and intraabdominal normotension, numerous and long lasting respiratory problems developed. The patient was discharged from our institution after 8 months. Though very rare in pediatric group, the possibility of a transverse colon volvulus must be considered in the differential diagnosis of acute large bowel obstruction.

Intestinal malrotation and catastrophic volvulus in infancy.

PubMed

Lee, Henry Chong; Pickard, Sarah S; Sridhar, Sunita; Dutta, Sanjeev

2012-07-01

Intestinal malrotation in the newborn is usually diagnosed after signs of intestinal obstruction, such as bilious emesis, and corrected with the Ladd procedure. The objective of this report is to describe the presentation of severe cases of midgut volvulus presenting in infancy, and to discuss the characteristics of these cases. We performed a 7-year review at our institution and present two cases of catastrophic midgut volvulus presenting in the post-neonatal period, ending in death soon after the onset of symptoms. These two patients also had significant laboratory abnormalities compared to patients with more typical presentations resulting in favorable outcomes. Although most cases of intestinal malrotation in infancy can be treated successfully, in some circumstances, patients' symptoms may not be detected early enough for effective treatment, and therefore may result in catastrophic midgut volvulus and death. Copyright © 2012 Elsevier Inc. All rights reserved.

Acute gastric volvulus: A vicious twist of tummy-case report.

PubMed

Kumar, Basudev; Kalra, Tarun; Namdeo, Ratnakar; Soni, Rajesh Kumar; Sinha, Ajit

2017-01-01

Gastric volvulus is an uncommon disorder and can present either in the acute or chronic setting with variable symptoms. A robust blood supply of the stomach from different sources does not allow ischemia to develop early. When it occurs in the acute scenario, patients present with severe epigastric pain and retching without vomiting. Together with inability to pass nasogastric tube, they constitute Borchardt's triad. We report a case which presented in the emergency department with severe abdominal pain, abdominal distension and vomiting and a previous history of pulmonary tuberculosis. An incidental finding of uterovaginal prolapse was present. A diagnosis of acute gastric volvulus with peritonitis was made and total gastrectomy with Roux-en-Y esophagojejunostomy for gangrenous and perforated stomach was performed. Primary gastric volvulus occurs in the absence of any defect in the diaphragm or adjacent organ pathology and may be caused by weakening of gastric supports. We wish to highlight if there is a possible association of primary gastric volvulus with uterovaginal prolapse reflecting a general laxity of body ligaments or with fibrosis of the lung secondary to pulmonary tuberculosis resulting into the twisting of the stomach. Acute gastric volvulus is a surgical emergency requiring early diagnosis and aggressive management, as a delay results into complications like gangrene and perforation which substantially increase the morbidity and mortality in these patients. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Fetal primary small bowel volvulus in a child without intestinal malrotation.

PubMed

Chung, Jae Hee; Lim, Gye-Yeon; We, Ji Sun

2013-07-01

Fetal primary small bowel volvulus without atresia or malrotation is an extremely rare but life-threatening surgical emergency. We report a case of primary small bowel volvulus that presented as sudden fetal distress and was diagnosed on the basis of the 'whirl-pool sign' of fetal sonography. This diagnosis led to emergency operation after birth at the third trimester with a good outcome. Although the pathogenesis of fetal primary small bowel volvulus is unclear, ganglion cell immaturity may play a role in the etiology. Copyright © 2013 Elsevier Inc. All rights reserved.

Inherited and predisposing factors in the development of gastric dilatation volvulus in dogs.

PubMed

Bell, Jerold S

2014-09-01

This review article summarizes what is known as well as what is undetermined concerning the inherited and environmental pathogenesis of gastric dilatation volvulus in dogs. The disorder primarily affects large and giant, deep-chested breeds. A concise description of a typical dog affected with gastric dilatation volvulus is presented. Copyright © 2014 Elsevier Inc. All rights reserved.

Manufactured volvulus.

PubMed

Zweifel, Noemi; Meuli, Martin; Subotic, Ulrike; Moehrlen, Ueli; Mazzone, Luca; Arlettaz, Romaine

2013-06-01

Malrotation with a common mesentery is the classical pathology allowing midgut volvulus to occur. There are only a few reports of small bowel volvulus without malrotation or other pathology triggering volvulation. We describe three cases of small bowel volvulus in very premature newborns with a perfectly normal intra-abdominal anatomy and focus on the question, what might have set off volvulation. In 2005 to 2008, three patients developed small bowel volvulus without any underlying pathology. Retrospective patient chart review was performed with special focus on clinical presentation, preoperative management, intraoperative findings, and potential causative explanations. Mean follow-up period was 46 months. All patients were born between 27 and 31 weeks (mean 28 weeks) with a birth weight between 800 and 1,000 g (mean 887 g). They presented with an almost identical pattern of symptoms including sudden abdominal distension, abdominal tenderness, erythema of the abdominal wall, high gastric residuals, and radiographic signs of ileus. All of them were treated with intensive abdominal massage or pelvic rotation to improve bowel movement before becoming symptomatic. Properistaltic maneuvers including abdominal massage and pelvic rotation may cause what we term a "manufactured" volvulus in very premature newborns. Thus, this practice was stopped. Georg Thieme Verlag KG Stuttgart · New York.

Volvulus in term and preterm infants - clinical presentation and outcome.

PubMed

Horsch, Sandra; Albayrak, Bilge; Tröbs, Ralf-Bodo; Roll, Claudia

2016-06-01

Our aim was to assess if term and preterm infants with volvulus showed different patterns with regard to pathogenesis, clinical presentation and outcome. We reviewed the medical records and imaging data of infants aged less than six months with volvulus treated in a single surgical referral centre from 2006-2013. Volvulus was diagnosed in 19 infants, with no anatomical anomaly in three of the 12 preterm infants and one of the seven term infants. Most cases (74%) presented during the first eight days of life. Later presentations occurred exclusively in preterm infants, with only one of the five having no anatomic anomalies. Bilious vomiting was the leading symptom in six of the seven term infants, while the symptoms in preterm infants were rather nonspecific. Intestinal necrosis, with the need for bowel resection, occurred in one term (14%) infant and nine (75%) preterm infants. The clinical presentation and outcome of volvulus differed between preterm and term infants, but the rate and distribution of underlying anomalies did not differ. Symptoms in preterm infants were often nonspecific and led to a delay in diagnosis. This might have contributed to the higher rate of intestinal necrosis in preterm infants. ©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Recurrent intestinal volvulus in midgut malrotation causing acute bowel obstruction: A case report

PubMed Central

Sheikh, Fayed; Balarajah, Vickna; Ayantunde, Abraham Abiodun

2013-01-01

Intestinal malrotation occurs when there is a disruption in the normal embryological development of the bowel. The majority of patients present with clinical features in childhood, though rarely a first presentation can take place in adulthood. Recurrent bowel obstruction in patients with previous abdominal operation for midgut malrotation is mostly due to adhesions but very few reported cases have been due to recurrent volvulus. We present the case of a 22-year-old gentleman who had laparotomy in childhood for small bowel volvulus and then presented with acute bowel obstruction. Preoperative computerised tomography scan showed small bowel obstruction and features in keeping with midgut malrotation. Emergency laparotomy findings confirmed midgut malrotation with absent appendix, abnormal location of caecum, ascending colon and small bowel. In addition, there were small bowel volvulus and a segment of terminal ileal stricture. Limited right hemicolectomy was performed with excellent postoperative recovery. This case is presented to illustrate a rare occurrence and raise an awareness of the possibility of dreadful recurrent volvulus even several years following an initial Ladd’s procedure for midgut malrotation. Therefore, one will need to exercise a high index of suspicion and this becomes very crucial in order to ensure prompt surgical intervention and thereby preventing an attendant bowel ischaemia with its associated high fatality. PMID:23556060

Recurrent intestinal volvulus in midgut malrotation causing acute bowel obstruction: A case report.

PubMed

Sheikh, Fayed; Balarajah, Vickna; Ayantunde, Abraham Abiodun

2013-03-27

Intestinal malrotation occurs when there is a disruption in the normal embryological development of the bowel. The majority of patients present with clinical features in childhood, though rarely a first presentation can take place in adulthood. Recurrent bowel obstruction in patients with previous abdominal operation for midgut malrotation is mostly due to adhesions but very few reported cases have been due to recurrent volvulus. We present the case of a 22-year-old gentleman who had laparotomy in childhood for small bowel volvulus and then presented with acute bowel obstruction. Preoperative computerised tomography scan showed small bowel obstruction and features in keeping with midgut malrotation. Emergency laparotomy findings confirmed midgut malrotation with absent appendix, abnormal location of caecum, ascending colon and small bowel. In addition, there were small bowel volvulus and a segment of terminal ileal stricture. Limited right hemicolectomy was performed with excellent postoperative recovery. This case is presented to illustrate a rare occurrence and raise an awareness of the possibility of dreadful recurrent volvulus even several years following an initial Ladd's procedure for midgut malrotation. Therefore, one will need to exercise a high index of suspicion and this becomes very crucial in order to ensure prompt surgical intervention and thereby preventing an attendant bowel ischaemia with its associated high fatality.

Mesenteric lipoblastoma presenting as a small intestinal volvulus in an infant: A case report and literature review.

PubMed

Nagano, Yuka; Uchida, Keiichi; Inoue, Mikihiro; Ide, Shozo; Shimura, Tadanobu; Hashimoto, Kiyoshi; Koike, Yuki; Kusunoki, Masato

2017-01-01

A 1-year-old boy with no underlying disorder presented with non-bilious vomiting since 4 days before admission. He was referred to our hospital and was diagnosed with a small bowel obstruction due to an intraabdominal tumor. Laparotomy revealed an intestinal volvulus with a soft and lobulated tumor arising from the mesentery. The resected tumor with a small part of the small bowel was diagnosed as lipoblastoma histologically. From a literature review, mesenteric lipoblastoma with an intestinal volvulus showed different characteristics such as greater frequency of vomiting and less frequency of abdominal mass as clinical symptoms, and the size of the tumor was smaller than that of the tumor without the intestinal volvulus. Copyright © 2013. Published by Elsevier Taiwan.

Primary small intestinal volvulus after laparoscopic rectopexy for rectal prolapse.

PubMed

Koizumi, Michihiro; Yamada, Takeshi; Shinji, Seiichi; Yokoyama, Yasuyuki; Takahashi, Goro; Hotta, Masahiro; Iwai, Takuma; Hara, Keisuke; Takeda, Kohki; Kan, Hayato; Takasaki, Hideaki; Ohta, Keiichiro; Uchida, Eiji

2018-02-01

Primary small intestinal volvulus is defined as torsion in the absence of congenital malrotation, band, or postoperative adhesions. Its occurrence as an early postoperative complication is rare. A 40-year-old woman presented with rectal prolapse, and laparoscopic rectopexy was uneventfully performed. She could not have food on the day after surgery. She started oral intake on postoperative day 3 but developed abdominal pain after the meal. Contrast-enhanced CT revealed torsion of the small intestinal mesentery. An emergent laparotomy showed small intestinal volvulus, without congenital malformation or intestinal adhesions. We diagnosed it as primary small intestinal volvulus. The strangulated intestine was resected, and reconstruction was performed. The patient recovered uneventfully after the second surgery. To the best of our knowledge, this is the first report of primary small intestinal volvulus occurring after rectopexy for rectal prolapse. Primary small intestinal volvulus could be a postoperative complication after laparoscopy. © 2018 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.

Intrauterine midgut volvulus without malrotation: Diagnosis from the ‘coffee bean sign’

PubMed Central

Park, Jun Seok; Cha, Seong Jae; Kim, Beom Gyu; Kim, Yong Seok; Choi, Yoo Shin; Chang, In Taik; Kim, Gwang Jun; Lee, Woo Seok; Kim, Gi Hyeon

2008-01-01

Fetal midgut volvulus is quite rare, and most cases are associated with abnormalities of intestinal rotation or fixation. We report a case of midgut volvulus without malrotation, associated with a meconium pellet, during the gestation period. This 2.79 kg, 33-wk infant was born via a spontaneous vaginal delivery caused by preterm labor. Prenatal ultrasound showed dilated bowel loops with the appearance of a ‘coffee bean sign’. This patient had an unusual presentation with a distended abdomen showing skin discoloration. An emergency laparotomy revealed a midgut volvulus and a twisted small bowel, caused by complicated meconium ileus. Such nonspecific prenatal radiological signs and a low index of suspicion of a volvulus during gestation might delay appropriate surgical management and result in ischemic necrosis of the bowel. Preterm labor, specific prenatal sonographic findings (for example, the coffee bean sign) and bluish discoloration of the abdominal wall could suggest intrauterine midgut volvulus requiring prompt surgical intervention. PMID:18322966

Prenatal diagnosis and management of an intestinal volvulus with meconium ileus and peritonitis.

PubMed

Takacs, Z F; Meier, C M; Solomayer, E-F; Gortner, L; Meyberg-Solomayer, G

2014-08-01

Fetal intestinal volvulus is a rare but serious finding with a high risk of potential life threatening fetal complications. Delay in diagnosis or treatment can increase mortality and morbidity. We report a case of mild fetal bowel dilatation at 30 weeks of gestation and intestinal volvulus presented by the 'whirl-sign', intestinal perforation and meconium peritonitis with fetal ascites and polyhydramnios at 33 weeks of gestation. This case emphasizes the role of examination of the bowel in third trimester ultrasound and the importance of quick decision to delivery and interdisciplinary perinatal management at suspected fetal volvulus with bowel necrosis and intraabdominal bleeding.

Pouch Volvulus in Patients Having Undergone Restorative Proctocolectomy for Ulcerative Colitis: A Case Series.

PubMed

Landisch, Rachel M; Knechtges, Paul M; Otterson, Mary F; Ludwig, Kirk A; Ridolfi, Timothy J

2018-06-01

Restorative proctocolectomy with IPAA improves quality of life in patients with medically refractory ulcerative colitis. Although bowel obstruction is common, pouch volvulus is rare and described only in case reports. Diagnosis can be challenging, resulting in delayed care and heightened morbidity. The purpose of this study was to delineate the symptoms and successful management strategies used in patients with IPAA volvulus that result in pouch salvage. This study was a case series. The study was conducted at a tertiary referral center for ulcerative colitis in Milwaukee, Wisconsin. Patients included those with volvulus of the IPAA. Over the study period (2010-2015), 6 patients were diagnosed with IPAA volvulus. The primary outcomes were symptom manifestation, diagnostic practices, and treatment of pouch volvulus. Six patients with ulcerative colitis were identified with pouch volvulus. The majority (n = 4) underwent a laparoscopic pouch creation and had early symptom manifestation after surgery. Complications preceding volvulus included pouch ulceration (n = 5) and pouchitis (n = 4). The most common presenting symptoms of volvulus were abdominal pain (n = 4) and obstipation (n = 4). Multiple imaging modalities were used, but volvulus was most frequently identified by CT scan. Management was primarily operative (n = 5), composed of excision of the pouch (n = 3), pouch-pexy (n = 1), and detorsion with defect closure (n = 1). Both operative and nonoperative treatment with endoscopic detorsion resulted in low morbidity and improved patient symptoms. This single-institution study is limited by its retrospective design and small number of patients. IPAA volvulus is a rare and challenging cause of bowel obstruction in ulcerative colitis. Heralding signs and symptoms, such as pouch ulceration and acute obstipation, should initiate a workup for a twisting pouch. Diagnosis, which is multimodal, must occur early to avert necrosis and allow for preservation of a well-functioning pouch. See Video Abstract at http://links.lww.com/DCR/A561.

Neonatal intestinal volvulus due to a persistent right vitelline artery.

PubMed

Loh, Amos H P; Prasad, Sai T R; Chew, Sung-Hock; Jacobsen, Anette S

2007-04-01

We report a case of neonatal intestinal volvulus around a persistent right vitelline artery, presenting as an aberrant parieto-mesenteric band on exploratory laparotomy. To our knowledge, this is the first case report in the English literature of a persistent right vitelline artery causing axial intestinal volvulus in a neonate. A review of the literature and the embryopathogenesis is discussed, as well as the importance of emergent diagnoses of such lesions.

[ACUTE MESENTEROAXIAL GASTRIC VOLVULUS: A REPORT ON ONE CASE

PubMed

Díaz, Juan; Martell, Alex; Ramírez, Lisbeth; Ulloa, Delia

1998-01-01

Acute gastric volvulus in children is uncommon. This paper reports a case presented in a 14-year-old female whose diagnosis was suspected preoperatively taking into account the Brouchardt triad (vomiting, epigastric pain and inability to pass the nasogastric tube into the stomach). The child underwent laparatomy and the final diagnosis was mesenteroaxial gastric volvulus complicated with gastric perforation. Closure of the perforation and gastropexy were performed and the operative results were satisfactory.

Acute transverse colon volvulus with secondary gastric isquemia. Case report.

PubMed

Sala-Hernández, Ángela; Pous-Serrano, Salvador; Lucas-Mera, Elí; Carvajal-Amaya, Nicolás

2016-03-01

Acute colonic volvulus accounts for 10% of all intestinal obstructions being the transverse colon volvulus an exceptional localization (2-4%). Late diagnosis is made as there are no pathognomonic clinical or radiological findings for this pathology. We present the case of an 81 year-old male with acute transverse colon volvulus that involved the gastric antrum causing irreversible ischemia. Subtotal gastrectomy, subtotal colectomy and reconstruction with Y en Roux gastrojejunostomy and ileosigmoid anastomosis was performed given the good overall status of the patient. Decompressive colonoscopy is not advised given the high probability of ischemic lesions in these cases; surgical exploration is mandatory in these circumstances. Surgical detortion with or without colopexia carries important recurrence rates. Treatment of choice includes colectomy with or without primary anastomosis. There are no reports on gastric ischemic necrosis in the setting of a transverse colon volvulus making this case unusual and unique.

Sigmoid volvulus in an adolescent girl: staged management with emergency colonoscopic reduction and decompression followed by elective sigmoid colectomy

PubMed Central

Patel, Ramnik V; Njere, Ike; Campbell, Alison; Daniel, Rejoo; Azaz, Amer; Fleet, Mahmud

2014-01-01

A case of acute sigmoid volvulus in a 14-year-old adolescent girl presenting with acute low large bowel obstruction with a background of chronic constipation has been presented. Abdominal radiograph and CT scan helped in diagnosis. She underwent emergency colonoscopic detorsion and decompression uneventfully. Lower gastrointestinal contrast study showed very redundant sigmoid colonic loop without any transition zone and she subsequently underwent elective sigmoid colectomy with good outcome. The sigmoid volvulus should be considered in the differential diagnosis of paediatric acute abdomen presenting with marked abdominal distention, absolute constipation and pain but without vomiting. Plain abdominal radiograph and the CT scan are helpful to confirm the diagnosis. Early colonoscopic detorsion and decompression allows direct visualisation of the vascular compromise, assessment of band width of the volvulus and can reduce complications and mortality. Associated Hirschsprung's disease should be suspected if clinical and radiological features are suggestive in which case a rectal biopsy before definitive surgery should be considered. PMID:25143313

Sigmoid volvulus in an adolescent girl: staged management with emergency colonoscopic reduction and decompression followed by elective sigmoid colectomy.

PubMed

Patel, Ramnik V; Njere, Ike; Campbell, Alison; Daniel, Rejoo; Azaz, Amer; Fleet, Mahmud

2014-08-20

A case of acute sigmoid volvulus in a 14-year-old adolescent girl presenting with acute low large bowel obstruction with a background of chronic constipation has been presented. Abdominal radiograph and CT scan helped in diagnosis. She underwent emergency colonoscopic detorsion and decompression uneventfully. Lower gastrointestinal contrast study showed very redundant sigmoid colonic loop without any transition zone and she subsequently underwent elective sigmoid colectomy with good outcome. The sigmoid volvulus should be considered in the differential diagnosis of paediatric acute abdomen presenting with marked abdominal distention, absolute constipation and pain but without vomiting. Plain abdominal radiograph and the CT scan are helpful to confirm the diagnosis. Early colonoscopic detorsion and decompression allows direct visualisation of the vascular compromise, assessment of band width of the volvulus and can reduce complications and mortality. Associated Hirschsprung's disease should be suspected if clinical and radiological features are suggestive in which case a rectal biopsy before definitive surgery should be considered. 2014 BMJ Publishing Group Ltd.

Cecal volvulus caused by endometriosis in a young woman.

PubMed

Ito, Daisuke; Kaneko, Susumu; Morita, Kouji; Seiichiro, Shimizu; Teruya, Masanori; Kaminishi, Michio

2015-06-24

Cecal volvulus is relatively rare. Moreover, to the best of our knowledge, a case of cecal volvulus caused by endometriosis has not yet been reported. A 41-year-old woman was admitted to our hospital with a 14-day history of subacute intermittent right lower quadrant abdominal pain. Simple abdominal radiography and abdominal computed tomography findings were suggestive of sigmoid volvulus, and she underwent an emergency colonoscopy. Following colonoscopic reduction, the patient's symptoms resolved quickly, and elective laparoscopic surgery was scheduled 2 weeks after admission. Intraoperative examination revealed a significantly distended cecum and ascending colon, which was twisted around a short rope-like adhesion that connected the cecum and the mesentery of the transverse colon, whereas the sigmoid colon was neither twisted nor extended. We laparoscopically performed an ileocecal resection. The postsurgery histopathological examination revealed the presence of endometrial tissue in the short rope-like adhesion. This finding confirmed that cecal volvulus in this patient was caused by endometriosis. Cecal volvulus should be considered in relatively young women who present with atypical right lower abdominal pain. Whenever possible, secondary factors should be evaluated preoperatively, especially in relatively young patients.

Small bowel volvulus in pregnancy with associated superior mesenteric artery occlusion.

PubMed

Esterson, Yonah B; Villani, Robert; Dela Cruz, Ronald A; Friedman, Barak; Grimaldi, Gregory M

Here we report the case of a pregnant 28-year-old who presented with acute upper abdominal pain. CT demonstrated midgut volvulus with short segment occlusion of the superior mesenteric artery (SMA). Emergent detorsion of the small bowel was performed, at which time underlying intestinal malrotation was discovered. Following detorsion, the SMA had a bounding pulse and did not require thrombectomy or revascularization. Fewer than 25 cases of midgut volvulus during pregnancy have been reported over the past 20years. To our knowledge, this is the first report of maternal midgut volvulus in which imaging captures the resultant occlusion of the SMA. Copyright © 2017 Elsevier Inc. All rights reserved.

Imaging diagnosis--Use of multiphasic contrast-enhanced computed tomography for diagnosis of mesenteric volvulus in a dog.

PubMed

Chow, Kathleen Ella; Stent, Andrew William; Milne, Marjorie

2014-01-01

A 4-year-old German shorthaired pointer presented with collapse and hematochezia. Radiographs showed gas and fluid-distended small intestines and loss of serosal detail. Ultrasound examination showed hypomotile, fluid-distended small intestines, and thrombosed jejunal veins. Multiphasic contrast-enhanced computed tomography was performed and showed a CT "whirl sign," an important but nonspecific sign of intestinal volvulus in human patients. At surgery, the majority of the small intestine was entangled in the volvulus and showed black discoloration. The patient was euthanized. Postmortem evaluation yielded a diagnosis of jejunoileal mesenteric volvulus secondary to a congenital omphalomesenteric duct remnant. © 2013 American College of Veterinary Radiology.

Pediatric colonic volvulus: A single-institution experience and review.

PubMed

Tannouri, Sami; Hendi, Aditi; Gilje, Elizabeth; Grissom, Leslie; Katz, Douglas

2017-06-01

Pediatric colonic volvulus is both rare and underreported. Existing literature consists only of case reports and small series. We present an analysis of cases (n=11) over 15 years at a single institution, focusing on workup and diagnosis. This was an institutional review board approved single-institution retrospective chart review of 11 cases of large bowel volvulus occurring over 15 years (2000-2015). In our series, the most common presenting symptoms were abdominal pain and distention. Afflicted patients often had prior abdominal surgery, a neurodevelopmental disorder or chronic constipation. Of the imaging modalities utilized in the 11 patients studied, colonic volvulus was correctly diagnosed by barium enema in 100% of both cases, CT in 55.6% of cases and by plain radiography of the abdomen in only 22.2%of cases. Colonic volvulus was confirmed by laparotomy in all cases. The cecum (n=5) was the most often affected colonic segment, followed by the sigmoid (n=3). Operative treatment mainly consisted of resection (63.6%) and ostomy creation (36.4%). Colopexy was performed in 18.2% of cases. Plain abdominal radiography may be performed as an initial diagnostic study, however, it should be followed CT or air or contrast enema in children where there is high clinical suspicion and who do not have indications for immediate laparotomy. CT may be the most specific and useful test in diagnosis of colonic volvulus and has the added advantage of detection of complications including bowel ischemia. We demonstrate a range of diagnostic and therapeutic modalities for pediatric colonic volvulus. This underscores the need for further study to draft standard best practices for this life-threatening condition. Prognosis Study: Level IV. Study of a Diagnostic Test: Level III. Copyright © 2017 Elsevier Inc. All rights reserved.

Gastrointestinal stromal tumor of Meckel's diverticulum: a rare cause of intestinal volvulus.

PubMed

Cengız, Fevzi; Sun, Mehmet Ali; Esen, Özgür Sipahi; Erkan, Nazif

2012-08-01

Meckel's diverticulum is the most common congenital abnormality of the gastrointestinal tract. Most cases are asymptomatic; however, when symptomatic, it is often misdiagnosed at presentation. Common complications presenting in adults include bleeding, obstruction, diverticulitis, and perforation. Tumors within a Meckel's diverticulum are rare. Herein, we present a gastrointestinal stromal tumor arising from the Meckel's diverticulum that led to intestinal obstruction by volvulus.

Segmental volvulus in the neonate: A particular clinical entity.

PubMed

Khen-Dunlop, Naziha; Beaudoin, Sylvie; Marion, Blandine; Rousseau, Véronique; Giuseppi, Agnes; Nicloux, Muriel; Grevent, David; Salomon, Laurent J; Aigrain, Yves; Lapillonne, Alexandre; Sarnacki, Sabine

2017-03-01

Complete intestinal volvulus is mainly related to congenital anomalies of the so-called intestinal malrotation, whereas segmental volvulus appears as a distinct entity, mostly observed during the perinatal period. Because these two situations are still lumped together, the aim of this study was to describe the particular condition of neonatal segmental volvulus. We analyzed the circumstances of diagnosis and management of 17 consecutives neonates operated for segmental volvulus more than a 10-year period in a single institution. During the same period, 19 cases of neonatal complete midgut volvulus were operated. Prenatal US exam anomalies were observed in 16/17 (94%) of segmental volvulus, significantly more frequently than in complete volvulus (p=0.003). Intestinal malposition was described peroperatively in all cases of complete volvulus, but also in 4/17 segmental volvulus (23%). Intestinal resection was performed in 88% of segmental volvulus when only one extensive intestinal necrosis was observed in complete volvulus. Parenteral nutrition was required in all patients with segmental volvulus with a median duration of 50days (range 5-251). Segmental volvulus occurs mainly prenatally and leads to fetal ultrasound anomalies. This situation, despite a limited length of intestinal loss, is associated to significant postnatal morbidity. Treatment study. Level IV. Copyright © 2016 Elsevier Inc. All rights reserved.

Management of the colonic volvulus in 2016.

PubMed

Perrot, L; Fohlen, A; Alves, A; Lubrano, J

2016-06-01

Colonic volvulus is the third leading cause of colonic obstruction worldwide, occurring at two principal locations: the sigmoid colon and cecum. In Western countries, sigmoid volvulus preferentially affects elderly men whereas cecal volvulus affects younger women. Some risk factors, such as chronic constipation, high-fiber diet, frequent use of laxatives, personal past history of laparotomy and anatomic predispositions, are common to both locations. Clinical symptomatology is non-specific, including a combination of abdominal pain, gaseous distention, and bowel obstruction. Abdominopelvic computerized tomography is currently the gold standard examination, allowing positive diagnosis as well as detection of complications. Specific management depends on the location, patient comorbidities and colonic wall viability, but treatment is an emergency in every case. If clinical or radiological signs of gravity are present, emergency surgery is mandatory, but is associated with high morbidity and mortality rates. For sigmoid volvulus without criteria of gravity, the ideal strategy is an endoscopic detorsion procedure followed, within 2 to 5 days, by surgery that includes a sigmoid colectomy with primary anastomosis. Exclusively endoscopic therapy must be reserved for patients who are at excessive risk for surgical intervention. In cecal volvulus, endoscopy has no role and surgery is the rule. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Intestinal Volvulus in Idiopathic Steatorrhea

PubMed Central

Warner, H. A.; Kinnear, D. G.; Cameron, D. G.

1963-01-01

Volvulus of the intestine has recently been observed in three patients with idiopathic steatorrhea in relapse. Two patients gave a history of intermittent abdominal pain, distension and obstipation. Radiographic studies during these attacks revealed obstruction at the level of the sigmoid colon. Reduction under proctoscopic control was achieved in one instance, spontaneous resolution occurring in the other. The third patient presented as a surgical emergency and underwent operative reduction of a small intestinal volvulus. Persistence of diarrhea and weight loss postoperatively led to further investigation and a diagnosis of idiopathic steatorrhea. In all cases, treatment resulted in clinical remission with a coincident disappearance of obstructive intestinal symptoms. The pathogenesis of volvulus in sprue is poorly understood. Atonicity and dilatation of the bowel and stretching of the mesentery likely represent important factors. The symptoms of recurrent abdominal pain and distension in idiopathic steatorrhea necessitate an increased awareness of intestinal volvulus as a complication of this disease. ImagesFig. 1Fig. 2Fig. 3Figs. 4 and 5Fig. 6 PMID:13998948

A Rare Case of Splenic Torsion with Sigmoid Volvulus in a 14-Year-Old Girl.

PubMed

Ahmadi, Hamid; Tehrani, Mahdieh Mohammad Khan

2016-01-01

Wandering spleen is an uncommon entity in adults and has been described only rarely with sigmoid volvulus, that rarely affects children and adolescents. It is usually described in adults.Wandering spleen characterized by the abnormal location of the spleen, caused by incomplete fusion of the four primary splenic ligaments, allowing the spleen to be mobile within the abdomen.The wandering spleen can lead to torsion and subsequent splenic infarction or rupture. Clinical suspicion plus urgent investigation and intervention are important. We present a rare clinical case of acute abdomen due to torsion of wandering spleen and volvulus of sigmoid in a 14-year-old girl presented with painful periumbilical mass. Detorsion of sigmoid occurred while undergoing exploratory laparotomy and splenectomy was performed. The possibility of torsion and its complication like gastric, pancreas tail and colon volvulus should be kept in mind in the differential diagnosis of the acute abdomen to avoid serious complications.

Gastric Volvulus: A Rare Entity Case Report and Literature Review

PubMed Central

Akhtar, Aisha; Sheikh, Abdul Ahad E; Sheikh, Abu Baker; Perisetti, Abhilash

2018-01-01

Gastric volvulus is a rare entity defined as an abnormal rotation of the stomach around itself. It is a diagnosis of exclusion; the clinical index of suspicion is always low and is mostly diagnosed on imaging or on the surgery table. When it occurs, it is an emergency due to the risk of strangulation and consequent gangrene of the stomach. Mesentero-axial (MA) gastric volvuli constitute one-third of all cases. Here, we are present an interesting case of acute MA gastric volvulus diagnosed with imaging and treated subsequently. PMID:29755908

Atraumatic splenic rupture and ileal volvulus following cocaine abuse.

PubMed

Ballard, David H; Smith, J Patrick; Samra, Navdeep S

2015-01-01

We present the case of a 38-year-old male with an atraumatic splenic rupture, hemoperitoneum, and ileal volvulus following acute cocaine intoxication. Computed tomography showed a "whirl sign", a subcapsular splenic hematoma with suspected peripheral laceration, and diffuse hemoperitoneum. At laparotomy, the spleen was confirmed to be the source of bleeding and was removed. A nonreducible volvulus was found at the distal ileum, and this segment of small bowel was removed. The patient had an uneventful postoperative recovery. Copyright © 2015 Elsevier Inc. All rights reserved.

Diagnosis and treatment of mesenteric volvulus in a red kangaroo (Macropus rufus).

PubMed

Knafo, S Emmanuelle; Rosenblatt, Alana J; Morrisey, James K; Flanders, James A; Thompson, Margret S; Knapp-Hoch, Heather M

2014-04-01

An 8-year-old male red kangaroo (Macropus rufus) was evaluated with a 2-week history of vomiting and anorexia. Four days prior, the patient became refractory to medical management. The kangaroo was admitted for diagnostic testing and treatment including whole body CT, blood work, and emergency laparotomy. CT findings of a severely enlarged stomach, splenic displacement, and a whirl sign were indicative of mesenteric volvulus with gastric dilatation-volvulus (GDV). Contrast enhancement of abdominal viscera suggested intact arterial blood supply; however, compression of the caudal vena cava and portal vein indicated venous obstruction. Results of preoperative blood work suggested biliary stasis without evidence of inflammation. Additionally, a tooth root abscess was diagnosed on the basis of results of CT. Exploratory laparotomy confirmed the diagnosis of mesenteric volvulus and GDV. The volvuli were corrected by clockwise derotation, and a gastropexy was performed. Tissue samples were obtained from the spleen and liver for evaluation. The kangaroo recovered from surgery, and the abscessed tooth was extracted 6 days later. Eight days after initial evaluation, the kangaroo was discharged. In the present report, the CT whirl sign was used to diagnose volvulus of the abdominal viscera, which suggests that this diagnostic indicator has utility in veterinary patients. Mesenteric volvulus with GDV was successfully treated in a nondomestic species. The tooth root abscess, a common condition in macropods, may explain the historic episodes of anorexia reported by the owner and may have contributed to the development of mesenteric volvulus and GDV in this kangaroo.

Intestinal volvulus: aetiology, morbidity, and mortality in Nigerian children.

PubMed

Ameh, E A; Nmadu, P T

2000-01-01

In developed countries, intestinal volvulus in children is most frequently due to malrotation. To review the experience in Nigeria, a retrospective analysis of 28 patients managed over 25 years at the Ahmadu Bello University Teaching Hospital, Zaria, Nigeria, was undertaken. There were 22 boys and 6 girls with an age range of 4 days to 14 years (median 4 years). There were equal numbers over and less than 5 years of age. Vomiting (89%) and abdominal distension (79%) were the most prominent features. Thirteen children (46%) had fever, associated with bowel gangrene in 5, while 8 (29%) presented with severe dehydration and shock. A plain abdominal radiograph was the only investigation performed, but the features were not specific for volvulus. In 11 children (39%) the volvulus was idiopathic, in 9 (32%) due to adhesions or bands, in 5 (18%) to malrotation, and in 1 each a Meckel's diverticulum, internal herniation, and ventriculoperitoneal shunt. Twenty-three patients had a small-bowel, 4 sigmoid, and 1 caecal volvulus. The bowel resection rate for gangrene was 46% (small bowel 9, sigmoid 3, caecum 1). All patients with malrotation had Ladd's procedure performed. Wound infections occurred in 10 patients (36%), complete wound dehiscence in 1, and recurrence in 1 (idiopathic terminal ileal volvulus). The mortality was 21%, mostly from overwhelming infection (2 neonates, 11-year-old, 3 >/= 5 years). Intestinal volvulus in our environment differs in aetiology from other reports. The resection rates are similar, however. This condition carries high morbidity and mortality.

Volvulus of the Small Bowel and Colon

PubMed Central

Kapadia, Muneera R.

2017-01-01

Volvulus of the intestines may involve either the small bowel or colon. In the pediatric population, small bowel volvulus is more common, while in the adult population, colonic volvulus is more often seen. The two most common types of colonic volvulus include sigmoid and cecal volvulus. Prompt diagnosis and treatment is imperative, otherwise bowel ischemia may ensue. Treatment often involves emergent surgical exploration and bowel resection. PMID:28144211

[Intestinal volvulus. Case report and a literature review].

PubMed

Santín-Rivero, Jorge; Núñez-García, Edgar; Aguirre-García, Manuel; Hagerman-Ruiz-Galindo, Gonzalo; de la Vega-González, Francisco; Moctezuma-Velasco, Carla Rubi

2015-01-01

Small bowel volvulus is a rare cause of intestinal obstruction in adult patients. This disease is more common in children and its aetiology and management is different to that in adults. A 30 year-old male with sarcoidosis presents with acute abdomen and clinical data of intestinal obstruction. Small bowel volvulus is diagnosed by a contrast abdominal tomography and an exploratory laparotomy is performed with devolvulation and no intestinal resection. In the days following surgery, he developed a recurrent small bowel volvulus, which was again managed with surgery, but without intestinal resection. Medical treatment for sarcoidosis was started, and with his clinical progress being satisfactory,he was discharged to home. Making an early and correct diagnosis of small bowel volvulus prevents large intestinal resections. Many surgical procedures have been described with a high rate of complications. Therefore, conservative surgical management (no intestinal resection) is recommended as the best treatment with the lowest morbidity and mortality rate. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

Small Bowel Volvulus in the Adult Populace of the United States: Results From a Population-Based Study

PubMed Central

Coe, Taylor M.; Chang, David C.; Sicklick, Jason K.

2015-01-01

Background Small bowel volvulus is a rare entity in Western adults. Greater insight into epidemiology and outcomes may be gained from a national database inquiry. Methods The Nationwide Inpatient Sample (1998–2010), a 20% stratified sample of United States hospitals, was retrospectively reviewed for small bowel volvulus cases (ICD-9 560.2 excluding gastric/colonic procedures) in patients ≥18-years old. Results There were 2,065,599 hospitalizations for bowel obstruction (ICD-9 560.x). Of those, there were 20,680 (1.00%) small bowel volvulus cases; 169 were attributable to intestinal malrotation. Most cases presented emergently (89.24%) and operative management was employed more frequently than non-operative (65.21% vs. 34.79%, P<0.0001). Predictors of mortality included age >50-years, Charlson comorbidity index ≥1, emergent admission, peritonitis, acute vascular insufficiency, coagulopathy, and non-operative management (P<0.0001). Conclusions As the first population-based epidemiological study of small bowel volvulus, our findings provide a robust representation of this rare cause of small bowel obstruction in American adults. PMID:26002189

An Unusual Case of Caecal Volvulus due to Appendicitis, Successfully Managed by Caecopexy.

PubMed

Bhatti, Samiullah; Khan, Mahmood Ayyaz; Farooka, Waris; Butt, Usman Ismat; Rehman, Usman Ali; Malik, Awais Amjad

2017-03-01

Caecal volvulus is a rare cause of intestinal obstruction. Caecal volvulus precipitated by acute appendicitis is even rarer. We report an unusual case of caecal volvulus with acute appendicitis as a cause. A 55-year female presented in surgical emergency with 3 days history of abdominal pain, distension and absolute constipation; and 2 days history of vomiting. Her past surgical history was significant for hysterectomy 5 years back. On examination, abdomen was distended and bowel sounds exaggerated. X-ray abdomen erect showed a single large air fluid level in the right hemiabdomen. A preoperative diagnosis of intestinal obstruction due to adhesions was made and patient prepared for exploratory laparotomy. On exploration, a huge caecum was lying in the midline and was twisted around a band arising from the appendix and attached deep into the pelvis. The appendix was densely inflammed. The volvulus was de-twisted in a counter clockwise manner. Viability of the caecum was confirmed and appendectomy was done. Caecopexy was performed and abdomen was closed. Postoperative recovery of the patient was uneventful and she was safely discharged on 5th postoperative day.

Acute gastric volvulus treated with laparoscopic reduction and percutaneous endoscopic gastrostomy.

PubMed

Jeong, Sang-Ho; Ha, Chang-Youn; Lee, Young-Joon; Choi, Sang-Kyung; Hong, Soon-Chan; Jung, Eun-Jung; Ju, Young-Tae; Jeong, Chi-Young; Ha, Woo-Song

2013-07-01

Acute gastric volvulus requires emergency surgery, and a laparoscopic approach for both acute and chronic gastric volvulus was reported recently to give good results. The case of a 50-year-old patient with acute primary gastric volvulus who was treated by laparoscopic reduction and percutaneous endoscopic gastrostomy is described here. This approach seems to be feasible and safe for not only chronic gastric volvulus, but also acute gastric volvulus.

Organo-axial volvulus of the small intestine: radiological case report and consideration for its mechanism.

PubMed

Ishiguro, Toshitaka; Hiyama, Takashi; Nasu, Katsuhiro; Akashi, Yoshimasa; Minami, Manabu

2017-07-01

Gastrointestinal volvulus is mainly classified into two subtypes, mesentero-axial volvulus and organo-axial volvulus. The detailed imaging findings of organo-axial volvulus of the small intestine have never been reported as far as we know. In this article, we report a case of organo-axial volvulus of the small intestine, focusing on the computed tomography (CT) findings. An 80-year-old man was radiologically diagnosed as having organo-axial volvulus of the terminal ileum and it was confirmed by open surgery without adhesion or any other anatomical abnormalities. CT showed two specific findings, split-bowel sign and rotating-C sign, which we think reflect pathophysiologic features of organo-axial volvulus. We think the pathogenic mechanism of organo-axial volvulus can be explained by the convergence of the reversed-rotational twist following the formation of a twisted but non-obstructive circular loop, even if there is no adhesion. Radiologists should be aware that organo-axial volvulus can occur even in the small intestine, and in the case of small bowel obstruction with single transition point, the two pathophysiologic signs mentioned above must be looked for to diagnose the possibility of organo-axial volvulus.

[Postnatal diagnosis of gastric volvulus revealing congenital diaphragmatic hernia].

PubMed

Aprahamian, A; Nouyrigat, V; Grévent, D; Hervieux, E; Chéron, G

2017-05-01

Postnatally diagnosed congenital diaphragmatic hernias (CDH) are rare and have a better prognosis than those diagnosed prenatally. Postnatal symptoms can be respiratory, digestive, or mixed. Gastric volvulus can reveal CDH. Symptoms are pain, abdominal distension, and/or vomiting. Upper gastrointestinal barium X-ray radiography provides the diagnosis. Prognosis is related to early surgical management in complicated forms with intestinal occlusion or sub-occlusion. We report on an infant who presented with vomiting, which revealed gastric volvulus associated with a CDH. Progression was favorable after surgical treatment. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Sigmoid Volvulus Through a Transmesenteric Hernia.

PubMed

Brandão, Pedro Nuno; Martins, Vilma; Silva, Cristina; Davide, José

2017-06-01

Internal hernias are a rare pathology with very low incidence. Transmesenteric hernias represent less than 10% of all cases and may occur at any age. They involve more often the small bowel and, more rarely, the colon. We present a case of a sigmoid volvulus through a transmesenteric hernia in a 19-year-old patient.

[Mesenteric volvulus associated with mesenteric lipoma: about a case].

PubMed

Dème, Hamidou; Badji, Nfally; Akpo, Léra Géraud; Touré, Mouhamed Hamine; Draha, Ronald; Niang, Fallou Gallas; Diop, Abdoulaye Dione; Niang, El Hadj

2016-01-01

We report the case of a 7-year old patient presenting for acute paroxysmal abdominal pain at the level of epigastrium associated with vomiting without involving blockage of materials and gas. Clinical examination and laboratory tests were unremarkable. Abdominal ultrasound was requested as a first line investigationa and showed a right echogenic homogeneous flank and iliac fossa mass with regular contours without vascular Doppler signal and associated with "whirl sign" of mesenteric vessels. On CT scan this mass was seen as a well-defined lipoma formation, exerting a mass effect on the cecum, which was in direct contact with mesenteric volvulus. Arrangement of the mesenteric vessels at their origin was normal. The diagnosis of mesenteric volvulus associated with lipoma was retained. Surgical management and histological analysis of the surgical specimen confirmed the diagnosis. This clinical case aims to highlight the contribution of ultrasound and CT scan in the diagnosis of midgut volvulus.

Volvulus and bowel obstruction in ATR-X syndrome-clinical report and review of literature.

PubMed

Horesh, Nir; Pery, Ron; Amiel, Imri; Shwaartz, Chaya; Speter, Chen; Guranda, Larisa; Gutman, Mordechai; Hoffman, Aviad

2015-11-01

Alpha thalassemia-mental retardation, X-linked (ATR-X) syndrome is a rare genetic disorder with a variety of clinical manifestations. Gastrointestinal symptoms described in this syndrome include difficulties in feeding, regurgitation and vomiting which may lead to aspiration pneumonia, abdominal pain, distention, and constipation. We present a 19-year-old male diagnosed with ATR-X syndrome, who suffered from recurrent colonic volvulus that ultimately led to bowel necrosis with severe septic shock requiring emergent surgical intervention. During 1 year, the patient was readmitted four times due to poor oral intake, dehydration and abdominal distention. Investigation revealed partial small bowel volvulus which resolved with non-operative treatment. Small and large bowel volvulus are uncommon and life-threatening gastrointestinal manifestations of ATR-X patients, which may contribute to the common phenomenon of prolonged food refusal in these patients. © 2015 Wiley Periodicals, Inc.

Chylous ascites associated with intestinal obstruction from volvulus due to Petersen's hernia: report of a case.

PubMed

Akama, Yuichi; Shimizu, Tetsuya; Fujita, Itsuo; Kanazawa, Yoshikazu; Kakinuma, Daisuke; Kanno, Hitoshi; Yamagishi, Aya; Arai, Hiroki; Uchida, Eiji

2016-12-01

Chylous ascites is an uncommon finding which is usually associated with recent abdominal/oncologic or retroperitoneal surgery. It is not usually seen in cases of acute obstruction. A patient who had previously undergone a laparoscopy-assisted distal gastrectomy with Roux-en-Y reconstruction for early gastric cancer presented with acute abdominal pain and epigastric fullness. Computed tomography suggested small bowel obstruction due to volvulus. We were able to reduce the volvulus and close a Petersen's hernia without resecting the bowel; a large amount of chylous ascites was an incidental finding. We present a case of chylous ascites occurring in a setting of small bowel obstruction due to Petersen's hernia, 3 years after successful distal gastrectomy for early gastric cancer, with no evidence of tumor recurrence.

Gastric dilatation-volvulus as complication after surgical removal of a splenic haemangiosarcoma in a dog.

PubMed

Marconato, L

2006-09-01

An 8-year-old crossbreed dog presented after one episode of acute collapse due to rupture of a splenic haemangiosarcoma. Following splenectomy the dog recovered well. Two days after discharge the dog re-presented because of gastric dilatation-volvulus (GDV) that eventually led to his death. Splenectomy to remove a voluminous splenic tumour may predispose to GDV and dogs may benefit from concurrent prophylactic gastropexy.

A case of closed loop small bowel obstruction within a strangulated incisional hernia in association with an acute gastric volvulus.

PubMed

Kosai, Nik Ritza; Gendeh, H S; Noorharisman, M; Sutton, Paul Anthony; Das, Srijit

2014-01-01

Small bowel obstruction is a common clinical problem presenting with abdominal distention, colicky pain, absolute constipation and bilious vomiting. There are numerous causes, most commonly attributed to an incarcerated hernia, adhesions or obstructing mass secondary to malignancy. Here we present an unusual cause of a small bowel obstruction secondary to an incarcerated incisional hernia in association with an acute organoaxial gastric volvulus.

Small bowel volvulus in the adult populace of the United States: results from a population-based study.

PubMed

Coe, Taylor M; Chang, David C; Sicklick, Jason K

2015-08-01

Small bowel volvulus is a rare entity in Western adults. Greater insight into epidemiology and outcomes may be gained from a national database inquiry. The Nationwide Inpatient Sample (1998 to 2010), a 20% stratified sample of United States hospitals, was retrospectively reviewed for small bowel volvulus cases (International Classification of Diseases, 9th Edition [ICD-9] code 560.2 excluding gastric/colonic procedures) in patients greater than or equal to 18 years old. There were 2,065,599 hospitalizations for bowel obstruction (ICD-9 560.x). Of those, there were 20,680 (1.00%) small bowel volvulus cases; 169 were attributable to intestinal malrotation. Most cases presented emergently (89.24%) and operative management was employed more frequently than nonoperative (65.21% vs 34.79%, P < .0001). Predictors of mortality included age greater than 50 years, Charlson comorbidity index greater than or equal to 1, emergent admission, peritonitis, acute vascular insufficiency, coagulopathy, and nonoperative management (P < .0001). As the first population-based epidemiological study of small bowel volvulus, our findings provide a robust representation of this rare cause of small bowel obstruction in American adults. Copyright © 2015 Elsevier Inc. All rights reserved.

Primary Segmental Volvulus Mimicking Ileal Atresia

PubMed Central

Rao, Sadashiva; B Shetty, Kishan

2013-01-01

Neonatal intestinal volvulus in the absence of malrotation is a rare occurrence and rarer still is the intestinal volvulus in absence of any other predisposing factors. Primary segmental volvulus in neonates is very rare entity, which can have catastrophic outcome if not intervened at appropriate time. We report two such cases, which were preoperatively diagnosed as ileal atresia and intraoperatively revealed to be primary segmental volvulus of the ileum. PMID:26023426

Computed tomography findings of acute gastric volvulus.

PubMed

Millet, Ingrid; Orliac, Celine; Alili, Chakib; Guillon, Françoise; Taourel, Patrice

2014-12-01

To assess the diagnostic performance of CT signs of gastric volvulus in both confirmed cases and control subjects. We retrospectively reviewed CT findings in 10 patients with surgically confirmed acute gastric volvulus and 20 control subjects with gastric distension. Two radiologists independently evaluated CT images for risk factors of gastric volvulus, direct findings of gastric volvulus by assessing gastric dilatation, the presence of an antropyloric transition point, the respective position of the different stomach segments and of the greater and lesser curvatures, stenosis of the gastric segments through the oesophageal hiatus and for findings of gastric ischemia. The sensitivity and specificity of each finding were calculated. The most sensitive direct signs of gastric volvulus were an antropyloric transition point without any abnormality at the transition zone and the antrum at the same level or higher than the fundus. The presence of both these two findings as diagnostic criteria of gastric volvulus had 100% sensitivity and specificity for the diagnosis of gastric volvulus. There was no association between CT signs of ischemia and final bowel ischemia at pathology. CT is both highly sensitive and specific for diagnosing acute gastric volvulus. CT is highly reliable for diagnosing acute gastric volvulus with two findings. The two signs are gastropyloric transition zone and abnormal location of the antrum. This allows fast surgical management of this emergency.

Intestinal volvulus: aetiology, morbidity and mortality in Tunisian children.

PubMed

Faouzi, Nouira; Yosra, Ben Ahmed; Said, Jlidi; Soufiane, Ghorbel; Aouatef, Charieg; Rachid, Khemakhem; Beji, Chaouachi

2011-01-01

Intestinal volvulus (IV) can occur at various sites of the gastrointestinal tract. In Europe, IV in children is most frequently due to malrotation but in Asia Ascaris infestation is a common cause. This report reviews the experience with IV in children in Tunisia; analyzes the aetiologies as well as the clinical presentations and the benefits of the Ladd's procedure in the treatment of the IV. The authors retrospectively reviewed the case records of all children with IV from January 2000 to December 2009 at the Tunis Children's Hospital. There were 22 boys and nine girls with an age range of one day to four years. Twenty-five (80%) patients presented during the neonatal period. The most common presentation was bilious vomiting and dehydration. The aetiology was identified in all patients: Anomalies in rotation (n=22), omphalo-mesenteric duct (n=3), internal hernia (n=3), cystic lymphangioma (n=2), caocal volvulus (n=1). The bowel resection rate for gangrene was 16%. All patients with malrotation had Ladd's procedure performed. Five patients (19%) developed wound infections. One patient presented with adhesive small bowel obstruction. There were no recurrences following Ladd's procedure for malrotation. Two neonates (6%) died from overwhelming infections. Intestinal volvulus in our environment differs in aetiology from other reports. The resection rates are not similar, however. Early diagnosis reduced the high morbidity and mortality in our study.

Delayed presentation of congenital diaphragmatic hernia manifesting as combined-type acute gastric volvulus: a case report and review of the literature.

PubMed

Anaya-Ayala, Javier E; Naik-Mathuria, Bindi; Olutoye, Oluyinka O

2008-03-01

Acute gastric volvulus associated with congenital diaphragmatic hernia is an unusual surgical emergency. We describe a case of an 11-year-old girl who presented with a 4-day history of abdominal pain, nonproductive retching, cough, and shortness of breath. A chest radiograph revealed a large air-fluid level in left hemithorax and the presence of intestinal loops with marked mediastinal deviation. Nasogastric decompression was unsuccessful. Via a thoracoscopic approach, the large fluid-filled stomach was percutaneously decompressed but could not be reduced. Through a left subcostal incision, a left-sided diaphragmatic defect about 4 x 5 cm was encountered. A large portion of small intestines, ascending and transverse colon, strangulated but viable stomach, and a large spleen herniated through the defect. The contents were reduced, revealing a combined gastric volvulus. Once the diaphragmatic defect was repaired primarily, there was insufficient space in the abdominal cavity to contain all the viscera reduced form the chest. Therefore, we placed an AlloDerm patch on the fascia and closed with a wound V.A.C (Kinetic Concepts Inc, San Antonio, TX). Two weeks later, the wound was definitively closed; she recovered uneventfully and was discharged home 3 days later. To our knowledge, only 26 previous cases of acute gastric volvulus complicating a congenital diaphragmatic hernia in children have been reported in the literature. Our patient represents the 27th case and the first combined type acute gastric volvulus case.

Volvulus without malposition--a single-center experience.

PubMed

Kargl, Simon; Wagner, Oliver; Pumberger, Wolfgang

2015-01-01

This is a single-center case series about the rare condition of volvulus without malposition and/or malrotation (VWM) in preterm babies. We focus on diagnostic difficulties, and our results should help to distinguish VWM as a distinct entity different from classical volvulus and segmental volvulus. Medical chart review of infants with VWM from 2003-2012 was used. A total of 15 patients were identified. All of them had volvulus in the absence of intestinal malposition or other associated intestinal pathologies. All patients were born prematurely. Emergency laparotomy was necessary in all 15 patients. Two groups were identified. Group 1 includes four patients with typical signs of meconium obstruction of prematurity (MOP). Small bowel resection was only necessary in one of these four patients, all survived without residual intestinal lesions. Group 2 consists of 11 patients without signs of MOP-small bowel resection and temporary enterostomy were necessary in all these children. Four patients presented with pneumatosis intestinalis on the abdominal plain film, suggesting necrotizing enterocolitis. Although two infants died, the survivors showed complete recovery. VWM is a distinct disease of prematurity. When associated with MOP, VWM has a favorable outcome of treatment. In contrast, VWM occurring in the absence of signs of meconium obstruction requires small bowel resection. VWM primarily affects the top of the midgut (ileum). Because of absent malposition, presentation of VWM may be uncharacteristic. Pneumatosis intestinalis in advanced VWM may lead to diagnostic difficulties and a delay in treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

Midgut volvulus following laparoscopic gastric banding--a rare and dangerous situation.

PubMed

Arbell, Dan; Koplewitz, Benjamin; Zamir, Gideon; Bala, Miklosh

2007-06-01

Intestinal malrotation is usually encountered in infants. Its main complication is midgut volvulus, a situation that presents itself with bilious vomiting. This symptom allows for early surgical treatment. A delay in diagnosis and treatment may lead to catastrophic sequelae, such as extensive bowel necrosis and death. This situation is rare but well known in adults. Laparoscopic gastric banding is a popular option for treating morbid obesity. One of the consequences of this procedure may be impaired vomiting when there is an obstruction below the band. In this paper, we present a case in which a patient suffered from midgut volvulus 4 years after a laparoscopic gastric banding. Owing to impaired vomiting, the diagnosis was delayed, therefore, severely endangering the patient. This case prompted us to suggest that malrotation should be actively sought after before or during any bariatric procedure.

Reverse intestinal rotation: a rare case of volvulus around a vitelline duct remnant

PubMed Central

Dreyer, Stephan; Kaczynski, Jakub; Hrobar, Petr; Collins, Patrick

2014-01-01

We present a rare case of reverse intestinal rotation with volvulus around a Meckel's diverticulum attached to a vitelline duct remnant. The diagnosis was established by CT. The patient was treated with exploratory laparotomy and small bowel resection. The patient made a full recovery and was discharged home on the seventh postoperative day. PMID:25246458

Diagnosis, treatment and prognosis of small bowel volvulus in adults: A monocentric summary of a rare small intestinal obstruction.

PubMed

Li, Xiaohang; Zhang, Jialin; Li, Baifeng; Yi, Dehui; Zhang, Chengshuo; Sun, Ning; Lv, Wu; Jiao, Ao

2017-01-01

Small bowel volvulus is a rare disease, which is also challenging to diagnose. The aims of this study were to characterize the clinical and radiological features associated with small bowel volvulus and treatment and to identify risk factors for associated small bowel necrosis. Patients with small bowel volvulus who underwent operations from January 2001 to December 2015 at the First Affiliated Hospital of China Medical University (Shenyang, China) were reviewed. Clinical, surgical and postsurgical data were registered and analyzed. Thirty-one patients were included for analysis. Fifteen patients were female (48.4%), with an average age of 47.7 years (18-79 years). The clinical signs and symptoms were unspecific and resembled intestinal obstruction. Clinical examination revealed abdominal distension and/or diffuse tenderness with or without signs of peritonitis. The use of CT scans, X-rays or ultrasound did not differ significantly between patients. In 9 of 20 patients that received abdominal CT scans, "whirlpool sign" on the CT scan was present. Secondary small bowel volvulus was present in 58.1% of patients, and causes included bands (3), adhesion (7), congenital anomalies (7) and stromal tumor (1). Out of the 31 patients, 15 with gangrenous small bowel had to undergo intestinal resection. Intestinal gangrene was present with higher neutrophils count (p<0.0001) and the presence of bloody ascites (p = 0.004). Three patients died of septic shock (9.68%), and the recurrence rate was 3.23%. To complete an early and accurate diagnosis, a CT scan plus physical exam seems to be the best plan. After diagnosis, an urgent laparotomy must be performed to avoid intestinal necrosis and perforation. After surgery, more than 90% of the patients can expect to have a favorable prognosis.

Comparison of Surgically Treated Large Versus Small Intestinal Volvulus (2009-2014).

PubMed

Davis, Elizabeth; Townsend, Forrest I; Bennett, Julie W; Takacs, Joel; Bloch, Christopher P

2016-01-01

The purpose of this retrospective study was to compare the outcome for dogs with surgically treated large versus small intestinal volvulus between October 2009 and February 2014. A total of 15 dogs met the inclusion criteria and underwent an abdominal exploratory. Nine dogs were diagnosed with large intestinal volvulus during the study period, and all nine had surgical correction for large intestinal volvulus. All dogs were discharged from the hospital. Of the seven dogs available for phone follow-up (74 to 955 days postoperatively), all seven were alive and doing well. Six dogs were diagnosed with small intestinal volvulus during the study period. One of the six survived to hospital discharge. Three of the six were euthanized at the time of surgery due to an extensive amount of necrotic bowel. Of the three who were not, one died postoperatively the same day, one died 3 days later, and one dog survived for greater than 730 days. Results concluded that the outcome in dogs with surgically corrected large intestinal volvulus is excellent, compared with a poor outcome in dogs with small intestinal volvulus. The overall survival to discharge for large intestinal volvulus was 100%, versus 16% for small intestinal volvulus.

Ileocolic intussusception mimicking the imaging appearance of midgut volvulus as a result of extrinsic duodenal obstruction.

PubMed

Gasparini, Flavia F; Navarro, Oscar M; Dasgupta, Roshni; Gerstle, J Ted; Thorner, Paul S; Manson, David E

2005-12-01

Duodenal obstruction caused by ileocolic intussusception in the absence of intestinal malrotation is extremely rare. We present and discuss the imaging findings in an infant with an intussusception secondary to a duplication cyst in whom sonography also showed inversion of the orientation of the mesenteric vessels and a distended stomach. A contrast medium study revealed a proximal duodenal obstruction with a beak appearance suggestive of midgut volvulus. At surgery, an ileocolic intussusception causing duodenal obstruction without concomitant malrotation or volvulus was found. The combination of duodenal obstruction and abnormal relationship of the mesenteric vessels as a result of ileocolic intussusception has not previously been reported in the literature.

Laparoscopic Approach for Metachronous Cecal and Sigmoid Volvulus

PubMed Central

Greenstein, Alexander J.; Zisman, Sharon R.

2010-01-01

Background: Metachronous colonic volvulus is a rare event that has never been approached laparoscopically. Methods: Here we discuss the case of a 63-year-old female with a metachronous sigmoid and cecal volvulus. Results: The patient underwent 2 separate successful laparoscopic resections. Discussion and Conclusion: The following is a discussion of the case and the laparoscopic technique, accompanied by a brief review of colonic volvulus. In experienced hands, laparoscopy is a safe approach for acute colonic volvulus. PMID:21605523

A small intestine volvulus caused by strangulation of a mesenteric lipoma: a case report.

PubMed

Kakiuchi, Yoshihiko; Mashima, Hiroaki; Hori, Naoto; Takashima, Hirotoshi

2017-03-13

An emergency department encounters a variety of cases, including rare cases of the strangulation of a mesenteric lipoma by the greater omentum band. A 67-year-old Japanese man presented with nausea, vomiting, and upper abdominal pain. There were no abnormalities detected by routine blood tests other than a slight rise in his white cell count. A contrast-enhanced computed tomography scan of his abdomen revealed a dilated intestine, a small intestine volvulus, and a well-capsulated homogeneous mass. He was suspected of having a small intestine volvulus that was affected by a mesenteric lipoma; therefore, single-port laparoscopic surgery was performed. Laparoscopy revealed a small intestine volvulus secondary to the strangulation of a mesenteric lipoma. The band and tumor were removed. He had no postoperative complications and was discharged on postoperative day 6. Although this case was an emergency, it showed that single-port laparoscopic surgery can be a safe, useful, and efficacious procedure.

A Peterson's hernia and subsequent small bowel volvulus: surgical reconstruction utilizing transverse colon as a new Roux-en-Y limb - 1 case.

PubMed

Jang, Jae Seong; Shin, Dong Gue

2013-12-01

Peterson's hernia is an internal hernia that can occur after Roux-en-Y anastomosis. It often accompanies small bowel volvulus and is prone to strangulation. Reconstruction of intestinal continuity after massive small bowel resection in a patient who undergoes near total gastrectomy and Roux-en-Y anastomosis can be difficult. A 74-year-old man who had undergone a near total gastrectomy and Roux-en-Y gastrojejunostomy for stomach cancer presented with abdominal pain. The preoperative computed tomography showed strangulated small bowel volvulus. During the emergent laparotomy, we found a strangulated Peterson's hernia with small bowel volvulus. After resection of the necrotized intestine, we made a new Roux-en-Y anastomosis connecting the remnant stomach and the jejunum with a transverse colon segment. We were safely able to connect the remnant stomach and the jejunum by making a new Roux-en-Y anastomosis utilizing a transverse colon segment as a new Roux-limb by two stage operation.

Unusual presentation of adult Marfan syndrome as a complex diaphragmatic hiatus hernia.

PubMed

Thakur, Shruti; Jhobta, Anupam; Sharma, Brij; Chauhan, Arun; Thakur, Charu S

2017-07-01

Marfan syndrome is multisystem connective tissue disorder that primarily involves the skeletal, cardiovascular, and ocular systems. The gastrointestinal complications in Marfan syndrome are rare, with only a few case reports described in the literature. We present a 25-year-old woman who presented with acute abdominal pain for 1 day. The imaging features revealed complex diaphragmatic hiatus hernia with organoaxial gastric volvulus. This is a unique case report about an adult patient with Marfan syndrome who presented with symptomatic paraesophageal hernia and organoaxial gastric volvulus. Copyright © 2014. Published by Elsevier Taiwan.

The high incidence of intestinal volvulus in Iran 1

PubMed Central

Saidi, Farrokh

1969-01-01

The incidence of intestinal volvulus gleaned from the world's medical literature spread over the past seven decades supports the contention that this bowel disorder has distinct geographical predilections. Sigmoid volvulus, invariably superimposed upon a redundancy of this part of the bowel, probably results from a functional disturbance of the colon mediated perhaps by a high-residue vegetable diet. The same factors appear to hold for small bowel volvulus, though caecal volvulus occurs strictly on the basis of preexisting anatomical abnormalities. ImagesFIG. 1 PMID:5350109

A neonate with intestinal volvulus without malrotation exhibiting early jaundice with a suspected fetal onset.

PubMed

Hara, Kaori; Kinoshita, Mari; Kin, Takane; Arimitsu, Takeshi; Matsuzaki, Yohei; Ikeda, Kazushige; Tomita, Hiroshi; Fujino, Akihiro; Kuroda, Tatsuo

2015-01-01

Intestinal volvulus without malrotation is a rare disease that causes volvulus of the small intestine despite normal intestinal rotation and fixation. We encountered a neonate with this disease who developed early jaundice and was suspected to have a fetal onset. This patient was characterized by early jaundice complicating intestinal volvulus without malrotation and is considered to have exhibited reduced fetal movement and early jaundice as a result of volvulus, necrosis, and hemorrhage of the small intestine in the fetal period. If abdominal distention accompanied by early jaundice is noted in a neonate, intestinal volvulus without malrotation and associated intraabdominal hemorrhage should be suspected and promptly treated.

Cecal volvulus: Report of a case and review of Japanese literature

PubMed Central

Katoh, Toshio; Shigemori, Tsunehiko; Fukaya, Ryo; Suzuki, Hiroshi

2009-01-01

A 78-year-old woman presented with fever, severe abdominal pain, and distension. She had been institutionalized for depression and senile dementia. Laboratory examinations disclosed a leucocytosis (WBC: 12 500/μL) and elevated levels of serum C-reactive protein (2.8 mEq/L). Diagnosis of acute cecal volvulus was made from a “coffee bean sign” on an abdominal computed tomography and a “beak sign” on a gastrographin enema. An emergent laparotomy confirmed the diagnosis and an ileo-colectomy with primary anastomosis was carried out. The patient recovered after intensive respiratory care and fluid therapy, and then returned to her former institution. A review of Japanese literature disclosed that: (1) a marked increase of aged patients with mental disability presenting with cecal volvulus, (2) adoption of ileo-colectomy as the standard surgical procedure, and (3) improved survival of the patients, were observed in the last decade. PMID:19469008

Small intestinal volvulus following laparotomy for endometrial clear cell carcinoma in a woman with a past history of total gastrectomy and Roux-en-Y anastomosis for gastric carcinoma.

PubMed

Chin, Georgiana S M; Heng, Robert; Neesham, Deborah E; Petersen, Rodney W

2002-12-01

Small intestinal volvulus is a rare complication following Roux-en-Y anastomosis. A 63-year-old woman was diagnosed with small intestinal volvulus following laparotomy for clear cell carcinoma of the endometrium. Her past medical history included a total gastrectomy and antecolic Roux-en-Y anastomosis for Duke's B gastric carcinoma. Operative findings were of transmesenteric herniation of the ileum through the Roux-en-Y small intestinal mesenteric window, with metastatic deposits fixing the hernia at its base to create a volvulus. The proximal transverse colon was very dilated and thin due to partial obstruction by the volvulus. Her treatment involved adhesiolysis and unraveling of the small intestinal volvulus. This is the first case report of a small intestinal volvulus following a Roux-en-Y anastomosis involving a metastatic gynacological malignancy.

Is isomerism a risk factor for intestinal volvulus?

PubMed

Landisch, Rachel M; Loomba, Rohit S; Salazar, Jose H; Buelow, Matthew W; Frommelt, Michele; Anderson, Robert H; Wagner, Amy J

2018-03-06

Isomerism, or heterotaxy syndrome, affects many organ systems anatomically and functionally. Intestinal malrotation is common in patients with isomerism. Despite a low reported risk of volvulus, some physicians perform routine screening and prophylactic Ladd procedures on asymptomatic patients with isomerism who are found to have intestinal malrotation. The primary aim of this study was to determine if isomerism is an independent risk factor for volvulus. Kid's Inpatient Database data from 1997 to 2012 was utilized for this study. Characteristics of admissions with and without isomerism were compared with a particular focus on intestinal malrotation, volvulus, and Ladd procedure. A logistic regression was conducted to determine independent risk factors for volvulus with respect to isomerism. 15,962,403 inpatient admissions were included in the analysis, of which 7970 (0.05%) patients had isomerism, and 6 patients (0.1%) developed volvulus. Isomerism was associated with a 52-fold increase in the odds of intestinal malrotation by univariate analysis. Of 251 with isomerism and intestinal malrotation, only 2.4% experienced volvulus. Logistic regression demonstrated that isomerism was not an independent risk factor for volvulus. Isomerism is associated with an increased risk of intestinal malrotation but is not an independent risk factor for volvulus. Prognosis study. Level III. Copyright © 2018 Elsevier Inc. All rights reserved.

Malrotation volvulus in a neonate: a novel surgical approach.

PubMed

Houben, C H; Mitton, S; Capps, S

2006-04-01

A newborn presented with bilious vomiting secondary to a malrotation and presumed perinatal-onset volvulus. Laparotomy was performed at 20 h of age at which the volvulus was derotated. Nevertheless the small but not the large bowel appeared to be completely ischaemic and non-viable. A second-look laparotomy was performed 24 h later with no significant improvement. In a new approach to the problem, nothing further was done and the child was left alone on parenteral nutrition and naso-gastric aspiration for 11 weeks. Further exploration showed that 40 cm of small bowel had survived intact and restorative surgery was carried out. Parenteral nutrition was discontinued after 9 months and the child, now aged 3.5 years, is thriving.

[Intestinal volvulus due to yeyunal duplication].

PubMed

Rodríguez Iglesias, P; Carazo Palacios, M E; Lluna González, J; Ibáñez Pradas, V; Rodríguez Caraballo, L

2014-10-01

Duplications of the alimentary tract are congenital malformations. The ileum is the most commonly affected organ. A lot of duplications are incidentally diagnosed but most of patients present a combination of pain or complications such as obstructive symptoms, intestinal intussusception, perforation or volvulus. We report the case of a 6-years-old girl, with intermittent abdominal pain and vomits for two months long. Laboratory work was completely normal and in the radiology analysis (abdominal sonography and magnetic resonance) a cystic image with intestinal volvulus was observed. The patient underwent laparotomy, Ladd's procedure was done and the cyst was resected. In conclusion, if a patient is admitted with abdominal pain and obstructive symptoms, it is important to consider duplication of the alimentary tract as a possible diagnosis.

[Pneumatosis cystoides intestinalis complicated with intestinal volvulus].

PubMed

Fuenmayor, Carmen Elena; Gainza, Carlos; García, Maryori; Zambrano, Richard; Torres, Gledys; Hernández, Yohanys; García, Anna

2017-01-01

Pneumatosis cystoides intestinalis is a rare condition in which multiple gas-filled cysts are found within the wall of the gastrointestinal tract either in the subserosa or submucosa. Its pathogenesis is uncertain and several pathogenic mechanisms have been proposed to explain its origin. The case of a male patient of 46 years with previous diagnosis of pneumatosis cystic intestinalis, who consulted for abdominal pain, vomiting and fever (39 °C) is presented. By the time of admission ther were signs of peritoneal irritation. The X-ray abdominal reported distension and intestinal hydro-air levels. Exploratory laparotomy was performed and revealed small bowel volvulus with strangulation of some intestinal segment. Histological diagnosis was pneumatosis cystic intestinalis complicated with Infarction trans-mural by intestinal volvulus. The patient evolved satisfactorily.

Volvulus of the liver with intrathoracic herniation.

PubMed

Moussa, G; Thomson, P M; Bohra, A

2014-10-01

We present a rare case of a liver volvulus, stomach and transverse colon herniating through the diaphragm. This scenario has not been reported previously. We discuss the presentation and management of this interesting case. A 65-year-old woman with a history of sarcoidosis and recurrent pericardial effusions, treated previously with a subxiphoid pericardial oval window fenestration, presented with acute upper abdominal pain radiating to the chest. High contrast computed tomography showed a volvulus of the liver with consequent venous congestion, and herniation of the liver, stomach and transverse colon through an anterior diaphragmatic defect. With liver perfusion threatened, an urgent laparoscopic repair was performed. The stomach and transverse colon were reduced, and the twisted left lobe of the liver was unrotated and reduced into the abdominal cavity. A double-sided synthetic mesh was used to repair the defect. The patient made an uneventful recovery. This is a novel complication of a patient presenting with abdominal pain with a previous history of pericardial window fenestration. A laparoscopic reduction and repair can be performed safely with excellent postoperative results.

[The diagnostic performance of color Doppler ultrasonography for newborn four cases of midgut volvulus accompanied by intestinal malrotation].

PubMed

Ikeshima, Yukari; Hisano, Katsuya; Morisawa, Takeshi; Inoue, Kozue; Shimamoto, Masahiro; Koujitani, Toshiaki; Yonetani, Masahiko; Yasufuku, Masao

2014-03-01

Midgut volvulus accompanied by intestinal malrotation is classified as a surgical emergency disease of the newborn, which emerges with the bilious vomiting or melena. This report presents four patients of this disease in our hospital, evaluated by color Doppler ultrasonography before surgical operation. All four patients were presented by bilious vomiting at the onset. By color Doppler ultrasonography method, the whirlpool sign which is the view of intestine and superior mesenteric vein rotated around with the axis of superior mesenteric artery, were shown in all cases. This whirlpool sign led to the diagnosis of midgut volvulus accompanied by intestinal malrotation. Intestinal contrast imaging was tested in three patients for the purpose of confirming the diagnosis. Repair of the volvulus and a ladd operation was performed in all four patients, without the excision of intestine because of no intestinal ischemic change. The clinical courses of four cases were good, and all patients were discharged within 17 days. Early diagnosis and timely surgical operation are essential for decreasing the possibility of occurring intestinal ischemic changes and improving clinical outcome after surgical operation. We propose that color Doppler ultrasonography is the powerful tool for the diagnosis of this disease, especially for the newborn, for whom the available diagnostic tests are limited.

The management of gastric volvulus in elderly patients.

PubMed

Zuiki, Toru; Hosoya, Yoshinori; Lefor, Alan Kawarai; Tanaka, Hiroyuki; Komatsubara, Toshihide; Miyahara, Yuzo; Sanada, Yukihiro; Ohki, Jun; Sekiguchi, Chuji; Sata, Naohiro

2016-01-01

Gastric volvulus is torsion of the stomach and requires immediate treatment. The optimal treatment strategy for patients with gastric volvulus is not established, because of significant variations in the cause and clinical course of this condition. We describe our experience with six elderly patients with gastric volvulus caused by different conditions using various approaches. This includes two patients managed with endoscopic reduction, followed by endoscopic or laparoscopic gastropexy. Endoscopy is a necessary first step to determine the optimal treatment strategy, and endoscopic reduction is often effective. The indications for surgical repair of gastric volvulus depend on the patient's overall condition, and several options are available. In some elderly patients with severe comorbidities, major surgery may have an unacceptably high risk. We propose a novel treatment strategy for gastric volvulus in the elderly and a review of the literature. Early endoscopy is necessary in patients with gastric volvulus. Endoscopic or laparoscopic gastropexy may be adequate therapy in selected elderly patients. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

[Prenatal intestinal volvulus: A life-threatening event with good long-term outcome].

PubMed

Raherison, R; Grosos, C; Lemale, J; Blondiaux, E; Sabourdin, N; Dahan, S; Rosenblatt, J; Guilbert, J; Jouannic, J-M; Mitanchez, D; Audry, G; Auber, F

2012-04-01

To describe the outcome of neonates with prenatal intestinal volvulus. All neonates with prenatal intestinal volvulus managed in our institution between May 2004 and December 2010 were retrospectively studied. All neonates with prenatal or neonatal diagnosis of prenatal intestinal volvulus were included. We analyzed age at diagnosis, fetal ultrasound (US) scan and magnetic resonance imaging (MRI) findings, clinical signs at birth, surgical findings, management, and postoperative outcome. Ten neonates with prenatal intestinal volvulus were identified. Prenatal US scans or MRI demonstrated evidence of meconium peritonitis in one fetus and bowel dilatation in 2 others. The mean gestational age at birth was 36 weeks (range, 31-38 weeks) and the mean birth weight was 2811g (range, 2050-3700g). One premature neonate developed respiratory distress and required ventilatory support at birth. In 7 neonates, clinical examination showed distended abdomen and emesis, whereas plain abdominal radiographs showed intestinal obstruction. All neonates underwent surgery and all had normal intestinal rotation, except one with total intestinal volvulus secondary to malrotation. Other causes of volvulus were suspected in 4 neonates: mesenteric defect (n=1), intestinal atresia (n=2) and narrow mesentery (n=1). Detorsion of total volvulus, ileostomy, or intestinal resection with primary anastomosis was performed in 2, 5, and 3 neonates, respectively. One patient with total intestinal volvulus secondary to malrotation died, whereas all other neonates survived. In one patient, the postoperative course was complicated by intestinal dysmotility of the distal small bowel requiring a secondary jejunoileostomy. Stoma closure was subsequently performed at 1 year of age with good outcome. One patient developed angiocholitis treated successfully with antibiotics. Median time to initiate enteral feeds was 7 days (range, 4-16 days) and all patients were subsequently weaned from parenteral nutrition. Median duration of parenteral nutrition was 29 days (range, 6-667 days). None of the patients had cystic fibrosis. Unlike postnatal volvulus, most prenatal volvulus occurs without malrotation. Although prenatal volvulus is a life-threatening condition, our results suggest that good long-term outcome can be achieved in most cases. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Cecal volvulus as a complication of gastric banding.

PubMed

Fakhro, Abdulla; O'Riordan, James M; Lawler, Leo P; O'Connell, P Ronan

2009-12-01

Surgery is an increasingly important management option for patients with obesity. Laparoscopic adjustable gastric banding is a procedure employed to treat morbid obesity refractory to medical therapy. It works by reducing the capacity of the stomach and promoting early satiety. We report the unusual case of a 33-year-old female who presented acutely 2 years following laparoscopic adjustable gastric banding with cecal volvulus and closed loop obstruction caused by displacement of the connecting tube.

Diagnosis, treatment and prognosis of small bowel volvulus in adults: A monocentric summary of a rare small intestinal obstruction

PubMed Central

Li, Xiaohang; Zhang, Jialin; Li, Baifeng; Yi, Dehui; Zhang, Chengshuo; Sun, Ning; Lv, Wu; Jiao, Ao

2017-01-01

Objectives Small bowel volvulus is a rare disease, which is also challenging to diagnose. The aims of this study were to characterize the clinical and radiological features associated with small bowel volvulus and treatment and to identify risk factors for associated small bowel necrosis. Methods Patients with small bowel volvulus who underwent operations from January 2001 to December 2015 at the First Affiliated Hospital of China Medical University (Shenyang, China) were reviewed. Clinical, surgical and postsurgical data were registered and analyzed. Results Thirty-one patients were included for analysis. Fifteen patients were female (48.4%), with an average age of 47.7 years (18–79 years). The clinical signs and symptoms were unspecific and resembled intestinal obstruction. Clinical examination revealed abdominal distension and/or diffuse tenderness with or without signs of peritonitis. The use of CT scans, X-rays or ultrasound did not differ significantly between patients. In 9 of 20 patients that received abdominal CT scans, “whirlpool sign” on the CT scan was present. Secondary small bowel volvulus was present in 58.1% of patients, and causes included bands (3), adhesion (7), congenital anomalies (7) and stromal tumor (1). Out of the 31 patients, 15 with gangrenous small bowel had to undergo intestinal resection. Intestinal gangrene was present with higher neutrophils count (p<0.0001) and the presence of bloody ascites (p = 0.004). Three patients died of septic shock (9.68%), and the recurrence rate was 3.23%. Conclusions To complete an early and accurate diagnosis, a CT scan plus physical exam seems to be the best plan. After diagnosis, an urgent laparotomy must be performed to avoid intestinal necrosis and perforation. After surgery, more than 90% of the patients can expect to have a favorable prognosis. PMID:28426721

Management of Colonic Volvulus

PubMed Central

Gingold, Daniel; Murrell, Zuri

2012-01-01

Colonic volvulus is a common cause of large bowel obstruction worldwide. It can affect all parts of the colon, but most commonly occurs in the sigmoid and cecal areas. This disease has been described for centuries, and was studied by Hippocrates himself. Currently, colonic volvulus is the third most common cause of large bowel obstruction worldwide, and is responsible for ∼15% of large bowel obstructions in the United States. This article will discuss the history of colonic volvulus, and the predisposing factors that lead to this disease. Moreover, the epidemiology and diagnosis of each type of colonic volvulus, along with the various treatment options will be reviewed. PMID:24294126

Acute caecal volvulus: A diagnostic paradigm.

PubMed

Chaudry, Tariq Hassan; Jamil, Munawar; Niaz, Khurram; Basher, Goher

2015-12-01

Acute Caecal Volvulus is a rare etiology in cases of Intestinal obstruction. We are presenting the data of 11 cases out of 1032 cases of intestinal obstruction between June 2008 to June 2013, who presented in the emergency department of Bahawal Victoria Hospital Bahawalpur. The mean age was 36±3.38 years with female preponderance in this retrospective study. The persistent distinctive features were chronic intermittent pain followed by the passage of flatus (54%), severe right lower quadrant colicky pain (31%) and abdominal distention (59%). Radiologically the dilated caecum with air fluid level (68%) was persistent finding with lateralization of small gut in few patients (12%). Cecopexy (18%), right Hemicolectomy with primary anastomosis (63.63%) and Ileostomy with mucous fistula (18%) were offered. Wound sepsis (27%) and chest infection (18%) were common sequele. Acute Caecal Volvulus diagnosis requires a heightened clinical suspicion on the basis of symptoms like RLQ pain/mass which is relieved by passage of flatus and early radiological assistance in all cases of intestinal obstruction.

Small intestinal volvulus caused by loose surgical staples.

PubMed

Page, Matthew P; Kim, Heung Bae; Fishman, Steven J

2009-09-01

Small intestinal volvulus beyond infancy is rare and usually has an iatrogenic cause. The authors describe an adolescent boy with small bowel volvulus secondary to the presence of free intraperitoneal surgical staples after a laparoscopic appendectomy.

Malrotation with transverse colon volvulus in early pregnancy: a rare cause for acute intestinal obstruction

PubMed Central

Sharma, Digvijoy; Parameshwaran, Rajesh; Dani, Tushar; Shetty, Prashanth

2013-01-01

Colonic volvulus is a relatively uncommon cause of large bowel obstruction, accounting for 10% of colonic obstructions. Volvulus of the transverse colon is quite rare, accounting for only 4–11% of all reported cases. We report an unusual case of documented volvulus of the transverse colon in a pregnant woman with intestinal malrotation and concomitant acute intestinal obstruction by congenital bands and adhesions. PMID:23964051

Chronic Gastric Volvulus with Laparoscopic Gastropexy after Endoscopic Reduction: A Case Report.

PubMed

Lee, Hye Yeon; Park, Jung Hyun; Kim, Sung Geun

2015-06-01

Gastric volvulus is an uncommon clinical entity. There are three types of gastric volvulus; organoaxial, mesenteroaxial and combined type. This condition can lead to a closed-loop obstruction or strangulation. Traditional surgical therapy for gastric volvulus is based on an open approach. Here we report a successful case of a patient with chronic gastric volvulus with a laparoscopic treatment. A 79-year-old woman came to the emergency department with epigastric pain accompanied by nausea for 2 weeks. Abdominal computed tomography revealed markedly distended stomach with transposition of gastroesophageal Junction and gastric antrum. Barium meal study revealed presence of the antrum was folded over 180 degrees that was located above gastroesophageal junction. We attempted an endoscopic reduction, but it was unsuccessful. The patient got laparoscopic anterior gastropexy. Based on our result, laparoscopic gastropexy can be considered as a good choice of the treatment for gastric volvulus.

Small bowel volvulus with jejunal diverticulum: Primary or secondary?

PubMed

Shen, Xiao-Fei; Guan, Wen-Xian; Cao, Ke; Wang, Hao; Du, Jun-Feng

2015-09-28

Small bowel volvulus, which is torsion of the small bowel and its mesentery, is a medical emergency, and is categorized as primary or secondary type. Primary type often occurs without any apparent intrinsic anatomical anomalies, while the secondary type is common clinically and could be caused by numerous factors including postoperative adhesions, intestinal diverticulum, and/or tumors. Here, we report a rare case of a 60-year-old man diagnosed with small bowel volvulus using multidetector computed tomography (MDCT) angiography. Further discovery by laparotomy showed one jejunal diverticulum, longer corresponding mesentery with a narrower insertion, and a lack of mesenteric fat. This case report includes several etiological factors of small bowel volvulus, and we discuss the possible cause of small bowel volvulus in this patient. We also highlight the importance of MDCT angiography in the diagnosis of volvulus and share our experience in treating this disease.

Small bowel volvulus with jejunal diverticulum: Primary or secondary?

PubMed Central

Shen, Xiao-Fei; Guan, Wen-Xian; Cao, Ke; Wang, Hao; Du, Jun-Feng

2015-01-01

Small bowel volvulus, which is torsion of the small bowel and its mesentery, is a medical emergency, and is categorized as primary or secondary type. Primary type often occurs without any apparent intrinsic anatomical anomalies, while the secondary type is common clinically and could be caused by numerous factors including postoperative adhesions, intestinal diverticulum, and/or tumors. Here, we report a rare case of a 60-year-old man diagnosed with small bowel volvulus using multidetector computed tomography (MDCT) angiography. Further discovery by laparotomy showed one jejunal diverticulum, longer corresponding mesentery with a narrower insertion, and a lack of mesenteric fat. This case report includes several etiological factors of small bowel volvulus, and we discuss the possible cause of small bowel volvulus in this patient. We also highlight the importance of MDCT angiography in the diagnosis of volvulus and share our experience in treating this disease. PMID:26420976

Volvulus of the gastrointestinal tract: appearances at multimodality imaging.

PubMed

Peterson, Christine M; Anderson, John S; Hara, Amy K; Carenza, Jeffrey W; Menias, Christine O

2009-01-01

Volvulus of the gastrointestinal tract, a clinically relevant cause of acute or recurring abdominal pain in adults, remains a diagnostic dilemma for radiologists in a large number of cases. The clinical symptoms associated with volvulus are often nonspecific and include pain and nausea with vomiting. Yet referring clinicians often rely on radiologists to make the diagnosis; volvulus is rarely diagnosed clinically. Radiography, fluoroscopy, and computed tomography are the imaging methods most often used for this purpose. Prompt diagnosis is critical to avoid life-threatening complications such as bowel ischemia and infarction. Thus, it is useful for radiologists to be familiar with the various appearances of volvulus throughout the gastrointestinal tract. (c) RSNA, 2009.

Immune recognition of Onchocerca volvulus proteins in the human host and animal models of onchocerciasis.

PubMed

Manchang, T K; Ajonina-Ekoti, I; Ndjonka, D; Eisenbarth, A; Achukwi, M D; Renz, A; Brattig, N W; Liebau, E; Breloer, M

2015-05-01

Onchocerca volvulus is a tissue-dwelling, vector-borne nematode parasite of humans and is the causative agent of onchocerciasis or river blindness. Natural infections of BALB/c mice with Litomosoides sigmodontis and of cattle with Onchocerca ochengi were used as models to study the immune responses to O. volvulus-derived recombinant proteins (OvALT-2, OvNLT-1, Ov103 and Ov7). The humoral immune response of O. volvulus-infected humans against OvALT-2, OvNLT-1 and Ov7 revealed pronounced immunoglobulin G (IgG) titres which were, however, significantly lower than against the lysate of O. volvulus adult female worms. Sera derived from patients displaying the hyperreactive form of onchocerciasis showed a uniform trend of higher IgG reactivity both to the single proteins and the O. volvulus lysate. Sera derived from L. sigmodontis-infected mice and from calves exposed to O. ochengi transmission in a hyperendemic area also contained IgM and IgG1 specific for O. volvulus-derived recombinant proteins. These results strongly suggest that L. sigmodontis-specific and O. ochengi-specific immunoglobulins elicited during natural infection of mice and cattle cross-reacted with O. volvulus-derived recombinant antigens. Monitoring O. ochengi-infected calves over a 26-month period, provided a comprehensive kinetic of the humoral response to infection that was strictly correlated with parasite load and occurrence of microfilariae.

Gastric dilatation and volvulus in a red panda (Ailurus fulgens).

PubMed

Neilsen, Colleen; Mans, Christoph; Colopy, Sara A

2014-11-01

To describe the successful management of gastric dilatation and volvulus (GDV) in a red panda. Clinical report. Red panda diagnosed with GDV. A 12-year-old male red panda (Ailurus fulgens) was evaluated for acute onset inappetence, staggering, collapse, and tachypnea. Gastric dilatation and volvulus (GDV) was diagnosed by radiography, abdominal ultrasonography, and exploratory celiotomy. Torsion of the stomach was corrected and an incisional gastropexy performed to prevent recurrence. No organs were devitalized, no other abnormalities detected, and the red panda recovered fully within 72 hours. GDV should be considered as a differential diagnosis for red pandas presenting with acute onset of unspecific signs such as collapse, inappetence, and abdominal distension. GDV in red pandas can be diagnosed and successfully treated as described in dogs. © Copyright 2014 by The American College of Veterinary Surgeons.

Predisposing factors for colonic torsion/volvulus in dogs: a retrospective study of six cases (1992-2010).

PubMed

Gagnon, Dominique; Brisson, Brigitte

2013-01-01

The purposes of this retrospective study were to review cases of colonic torsion/volvulus between July 1992 and August 2010 and to determine if any predisposing factors exist for the development of this condition. Six dogs were diagnosed with colonic torsion/volvulus during the study period. Four dogs had a history of previous gastric dilation-volvulus (GDV) with prophylactic gastropexy. Three of six dogs diagnosed with colonic torsion/volvulus had large intestinal entrapment and strangulation around the gastropexy site at the time of surgery. The history, clinical signs, physical examination, and radiologic findings were not specific for colonic torsion/volvulus in any dog. Early exploratory laparotomy was indicated to confirm the diagnosis and perform surgical correction of the affected bowel segments. Three of five dogs that underwent surgery had a left abdominal wall colopexy performed. All five dogs that underwent surgery in this study survived postoperatively. One patient was euthanized without surgical intervention. Results suggest that colonic torsion/volvulus should be considered in any large-breed dog with nonspecific gastrointestinal clinical signs and a history of previous gastropexy. Early recognition and prompt treatment of this condition may result in a good outcome.

Appropriate treatment of acute sigmoid volvulus in the emergency setting

PubMed Central

Lou, Zheng; Yu, En-Da; Zhang, Wei; Meng, Rong-Gui; Hao, Li-Qiang; Fu, Chuan-Gang

2013-01-01

AIM: To investigate an appropriate strategy for the treatment of patients with acute sigmoid volvulus in the emergency setting. METHODS: A retrospective review of 28 patients with acute sigmoid volvulus treated in the Department of Colorectal Surgery, Changhai Hospital, Shanghai from January 2001 to July 2012 was performed. Following the diagnosis of acute sigmoid volvulus, an initial colonoscopic approach was adopted if there was no evidence of diffuse peritonitis. RESULTS: Of the 28 patients with acute sigmoid volvulus, 19 (67.9%) were male and 9 (32.1%) were female. Their mean age was 63.1 ± 22.9 years (range, 21-93 years). Six (21.4%) patients had a history of abdominal surgery, and 17 (60.7%) patients had a history of constipation. Abdominal radiography or computed tomography was performed in all patients. Colonoscopic detorsion was performed in all 28 patients with a success rate of 92.8% (26/28). Emergency surgery was required in the other two patients. Of the 26 successfully treated patients, seven (26.9%) had recurrent volvulus. CONCLUSION: Colonoscopy is the primary emergency treatment of choice in uncomplicated acute sigmoid volvulus. Emergency surgery is only for patients in whom nonoperative treatment is unsuccessful, or in those with peritonitis. PMID:23946604

Acute gastric volvulus in operated cases of tracheoesophageal fistula

PubMed Central

Joshi, Milind; Parelkar, Sandesh

2010-01-01

A report of two neonates of esophageal atresia with tracheoesophageal fistula who had acute gastric volvulus in the postoperative period and required gastropexy after correction of the volvulus. Such postoperative complication has not been reported in the literature so far. PMID:21180502

Magnetic Resonance Imaging Diagnosis of Volvulus through Mesenteric Defect in Neonate

PubMed Central

Leopold, Scott; Al-Qaraghouli, Mohammed; Hussain, Naveed; Finck, Christine

2016-01-01

Antenatal midgut volvulus is a rare surgical emergency in which bowel is severely compromised. Rarely the etiology is a mesenteric defect. Early diagnosis is essential and lifesaving in the immediate newborn period. Typically upper gastrointestinal or ultrasound imaging can be suggestive of the diagnosis of volvulus in the neonate. Sometimes, however, the diagnosis may be elusive. Herein, we report on the use of neonatal magnetic resonance imaging to diagnose a midgut volvulus that occurred through a congenital mesenteric defect. PMID:27551577

Gastric volvulus as a complication in the recipients after adult living donor liver transplantation.

PubMed

Shirouzu, Yasumasa; Sakurai, Koichi; Asonuma, Katsuhiro; Inomata, Yukihiro

2010-04-01

We report 4 adult cases of mesenteroaxial gastric volvulus after living donor liver transplantation (LDLT). All 4 recipients were female with a median age of 31 years (range, 21-69). All had undergone right lobe LDLT. Gastric volvulus developed on postoperative days (POD) 4-30, and all were successfully treated with an endoscopic correction procedure. Two of 4 needed a repeated correction procedure and 1 needed a surgical revision for the recurrent volvulus. Although this type of the complication is unusual, earlier post-transplant endoscopic intervention is useful to reverse the pyloroantral obstruction. These cases let us recognize that gastric volvulus is one of the complications after right lobe LDLT. Copyright 2010 Mosby, Inc. All rights reserved.

Hemorrhagic shock caused by sigmoid colon volvulus: An autopsy case

PubMed Central

Sato, Hiroaki; Tanaka, Toshiko; Tanaka, Noriyuki

2011-01-01

Summary Background Many reports have described sigmoid volvulus, but fatal hemorrhagic shock resulting from the rupture of the involved artery has not been reported as a complication of a sigmoid volvulus. Case Report A 71-year-old man with slight abdominal pain and obstipation in hypotension died at a nursing home without seeing a doctor. At autopsy, a mesenteric hematoma and hemoperitoneum was observed with approximately 1,000 ml of blood in the abdominal cavity. The sigmoid colon and the mesentery were twisted at an adhesion site of a sigmoid colon to an ileum, and the condition was determined to be a sigmoid volvulus. The volvulus was observed to be loosened. The inferior mesenteric artery was incorporated into the twisted part of the mesentery, but remained patent, and its peripheral branch near the hematoma ruptured without histological abnormality. Conclusions Since ischemic-reperfusion injury occurs with a temporarily occluded artery, the acute re-loading of blood flow may injure the distal vessels after spontaneous reduction of compression by loosening of the volvulus. PMID:22129905

Utility of CT Findings in the Diagnosis of Cecal Volvulus.

PubMed

Dane, Bari; Hindman, Nicole; Johnson, Evan; Rosenkrantz, Andrew B

2017-10-01

The objective of our study was to assess the utility of CT features in the diagnosis of cecal volvulus. Forty-three patients undergoing CT for cecal volvulus and with surgical or clinical follow-up were included. Two radiologists (11 years and 1 year of experience) evaluated CT examinations for the following: whirl sign, abnormal cecal position, "bird beak" sign, severe cecal distention, mesenteric engorgement, a newly described "central appendix" sign (defined as abnormal appendix position near midline), and overall impression for cecal volvulus. Univariable and multivariable assessments were performed. Patients with CT examinations in which the appendix was not visible were excluded from calculations involving the central appendix sign. Fifty-one percent (n = 22) of patients had cecal volvulus. All CT findings were significantly more common in patients with cecal volvulus (p < 0.01) other than mesenteric engorgement for reader 1 (p = 0.332). Readers 1 and 2 identified the central appendix sign in 92.9% and 92.3% of patients with volvulus versus in 37.5 and 31.1% of patients without volvulus. The whirl sign exhibited a sensitivity for cecal volvulus of 90.9% for reader 1 and 95.5% for reader 2, and a specificity of 61.9% for both readers. Abnormal cecal position exhibited a sensitivity of 90.0% for reader 1 and 100.0% for reader 2 and a specificity of 66.7% and 38.1%. The bird beak sign exhibited a sensitivity of 86.4% for reader 1 and 100.0% for reader 2 and a specificity of 85.7% and 71.4%. Severe cecal distention exhibited a sensitivity of 100.0% for both readers and a specificity of 81.0% and 61.9%. Mesenteric engorgement exhibited a sensitivity of 40.9% for reader 1 and 100.0% for reader 2 and a specificity of 76.2% and 71.4%. The central appendix sign exhibited a sensitivity of 92.9% for reader 1 and 92.3% for reader 2 and a specificity of 62.5% and 68.8%. Overall impression exhibited a sensitivity of 100.0% for both readers and a specificity of 76.2% and 57.1%. At multivariable analysis, the AUC for cecal volvulus ranged from 0.787 to 0.931, and the whirl sign was an independent predictor of volvulus for both readers (p ≤ 0.014); the central appendix sign was also an independent predictor in patients with a visualized appendix for reader 2 (p ≤ 0.001). CT exhibited high diagnostic performance and very high sensitivity for cecal volvulus. The whirl sign was a significant independent predictor of volvulus for both readers.

Segmental jejunal entrapment, volvulus, and strangulation secondary to intra-abdominal adhesions in a dog.

PubMed

Di Cicco, Michael F; Bennett, R Avery; Ragetly, Chantal; Sippel, Kate M

2011-01-01

A 4 yr old, castrated male dachshund was presented for lethargy, restlessness, a "hunched" posture, and a painful abdomen. A gastric foreign body had been surgically removed 24 mo previously. Exploratory celiotomy revealed a devitalized segment of jejunum with twisted mesentery. Several adhesions and fibrous bands were present within the abdomen, presumptively from the previous gastric foreign body surgery. Histopathology determined that a fibrous tissue band caused entrapment of the segment of intestine and its mesentery resulting in volvulus and ischemic necrosis of the intestine. This case is unique because it involved a focal area of the jejunum that was incarcerated in fibrous adhesions.

Meconium pseudocyst secondary to ileum volvulus perforation without peritoneal calcification: a case report.

PubMed

Valladares, Esther; Rodríguez, David; Vela, Antonio; Cabré, Sergi; Lailla, Josep Maria

2010-08-31

A case of giant meconium pseudocyst secondary to ileum volvulus perforation is presented. Conventional radiographic features of meconium peritonitis with secondary meconium pseudocyst formation are well described. Our case is unusual in comparison to other cases reported in the literature and needs to be reported because the meconium pseudocyst presented without the typical ultrasound features (calcifications, polyhydramnios and ascites) and was initially identified as an abdominal mass. We describe the case of a 29-year-old Caucasian woman in her third trimester of pregnancy, in which an abdominal mass was detected in the fetus. The newborn was diagnosed in the early neonatal period with meconium pseudocyst secondary to ileum volvulus perforation. The prenatal appearance of a meconium pseudocyst can be complemented by other signs of bowel obstruction (if present) such as polyhydramnios and fetal bowel dilatation. This is an original case report of interest to all clinicians in the perinatology and fetal ultrasound field. We consider that the utility of this case is the recognition that a meconium pseudocyst might appear without the typical ultrasound features and should be considered as a differential diagnosis when an echogenic intra-abdominal cyst is seen.

Gastric volvulus following diagnostic upper gastrointestinal endoscopy: a rare complication.

PubMed

Karthikeyan, Vilvapathy Senguttuvan; Sistla, Sarath Chandra; Ram, Duvuru; Rajkumar, Nagarajan

2014-02-10

Esophagogastroduodenoscopy (EGD) is a commonly used, safe diagnostic modality for evaluation of epigastric pain and rarely its major complications include perforation, haemorrhage, dysrhythmias and death. Gastric volvulus has been reported to complicate percutaneous endoscopic gastrostomy but its occurrence after diagnostic EGD has not yet been reported in literature. The successful management relies on prompt diagnosis and gastric untwisting, decompression and gastropexy or gastrectomy in full thickness necrosis of the stomach wall. A 38-year-old woman presented with epigastric pain and EGD showed pangastritis. Immediately after EGD she developed increased severity of pain, vomiting and abdominal distension. Emergency laparotomy carried out for peritoneal signs revealed eventration of left hemidiaphragm with the stomach twisted anticlockwise in the longitudinal axis. After gastric decompression and untwisting of volvulus, anterior gastropexy and gastrostomy was carried out. Hence, we report this rare complication of diagnostic endoscopy and review the existing literature on the management.

Wandering spleen with gastric volvulus and intestinal non-rotation in an adult male patient

PubMed Central

Kohda, Eiichi; Iizuka, Yuo; Nagamoto, Masashi; Ishii, Tomotaka; Saida, Yoshihisa; Shimizu, Norikazu; Gomi, Tatsuya

2013-01-01

We report an extremely rare case of wandering spleen (WS) complicated with gastric volvulus and intestinal non-rotation in a male adult. A 22-year-old man who had been previously treated for Wilson disease was admitted with severe abdominal pain. Radiological findings showed WS in the midline of the pelvic area. The stomach was mesenteroaxially twisted and intestinal non-rotation was observed. Radiology results did not show any evidence of splenic or gastrointestinal (GI) infarction. Elective emergency laparoscopy confirmed WS and intestinal non-rotation; however, gastric volvulus was not observed. It was suspected that the stomach had untwisted when gastric and laparoscopic tubes were inserted. Surgery is strongly recommended for WS because of the high risk of serious complications; however, some asymptomatic adult patients are still treated conservatively, such as the patient in this study. The present case is reported with reference to the literature. PMID:24349711

Wandering spleen with gastric volvulus and intestinal non-rotation in an adult male patient.

PubMed

Ooka, Minako; Kohda, Eiichi; Iizuka, Yuo; Nagamoto, Masashi; Ishii, Tomotaka; Saida, Yoshihisa; Shimizu, Norikazu; Gomi, Tatsuya

2013-01-01

We report an extremely rare case of wandering spleen (WS) complicated with gastric volvulus and intestinal non-rotation in a male adult. A 22-year-old man who had been previously treated for Wilson disease was admitted with severe abdominal pain. Radiological findings showed WS in the midline of the pelvic area. The stomach was mesenteroaxially twisted and intestinal non-rotation was observed. Radiology results did not show any evidence of splenic or gastrointestinal (GI) infarction. Elective emergency laparoscopy confirmed WS and intestinal non-rotation; however, gastric volvulus was not observed. It was suspected that the stomach had untwisted when gastric and laparoscopic tubes were inserted. Surgery is strongly recommended for WS because of the high risk of serious complications; however, some asymptomatic adult patients are still treated conservatively, such as the patient in this study. The present case is reported with reference to the literature.

Gastric dilatation and volvulus in a brachycephalic dog with hiatal hernia.

PubMed

Aslanian, M E; Sharp, C R; Garneau, M S

2014-10-01

A brachycephalic dog was presented with an acute onset of retching and abdominal discomfort. The dog had a chronic history of stertor and exercise intolerance suggestive of brachycephalic airway obstructive syndrome. Radiographs were consistent with a Type II hiatal hernia. The dog was referred and within hours of admission became acutely painful and developed tympanic abdominal distension. A right lateral abdominal radiograph confirmed gastric dilatation and volvulus with herniation of the pylorus through the hiatus. An emergency exploratory coeliotomy was performed, during which the stomach was derotated, and an incisional gastropexy, herniorrhaphy and splenectomy were performed. A staphylectomy was performed immediately following the exploratory coeliotomy. The dog recovered uneventfully. Gastric dilatation and volvulus is a potentially life-threatening complication that can occur in dogs with Type II hiatal hernia and should be considered a surgical emergency. © 2014 British Small Animal Veterinary Association.

[Malrotation with or without volvulus].

PubMed

Heidsma, Charlotte M; Hulsker, Caroline C C; van der Zee, David; Kramer, William H

2015-01-01

Malrotation occurs when there is a failure in the intestinal rotation leading to abnormal fixation to the abdominal wall and a mesentery with a short root. Volvulus is a life-threatening complication of malrotation. It can lead to irreversible intestinal necrosis and requires immediate attention. Early recognition of malrotation and surgical correction could prevent the onset of volvulus. We describe 3 cases of children with a malrotation. Case A involves a 2-year-old boy who suffered from repeated episodes of vomiting. Case B, a 1-month-old female, was taken to the general practitioner after acute onset of crying and flexing of the legs. Case C, a 5-year-old-boy with no medical history, had started vomiting hourly. In presenting these 3 cases, we highlight the dangers of untreated malrotation and make recommendations on how to manage a patient suspected of having this congenital abnormality.

Full-thickness small intestine necrosis with midgut volvulus, distributed in a patchy fashion, is reversible with moderate blood flow: resumption of normal function to non-viable intestine.

PubMed

Amano, Hizuru; Uchida, Hiroo; Kawashima, Hiroshi; Tanaka, Yujiro; Kishimoto, Hiroshi

2014-08-01

Midgut volvulus is a highly life-threatening condition that carries a high risk of short gut syndrome. We report a case of catastrophic neonatal midgut volvulus in which second-look laparotomy revealed apparently non-viable remnant small intestine but with a moderate blood supply. Full-thickness small intestine necrosis was distributed in a patchy fashion, with non-viable and necrotic areas distributed so widely that no portion of the intestine could be resected. A section of full-thickness necrotic intestine preserved at surgery was able to regenerate, and normal function was restored over a period of 1 month. This case indicated that intestinal resumption may be dependent on blood flow. Even when intestinal viability is questionable, preservation enables the chance of regeneration if moderate blood flow is present.

Gastric volvulus through morgagni hernia: an easily overlooked emergency.

PubMed

Sonthalia, Nikhil; Ray, Sayantan; Khanra, Dibbendhu; Saha, Avishek; Maitra, Subhasis; Saha, Manjari; Talukdar, Arunansu

2013-06-01

Intractable vomiting in an elderly patient is an emergency condition requiring prompt diagnosis and intervention. Acute gastric outlet obstruction due to gastric volvulus through Morgagni-type diaphragmatic hernia is an exceedingly rare cause of this nonspecific complaint. Our aim was to highlight that Morgagni hernia, although rare in adults, should be suspected in the appropriate clinical setting, and that a clue toward diagnosis often comes from routine chest and abdominal x-ray studies. In addition, we emphasize the atypical radiological findings and importance of emergency surgical intervention in such a case. We describe the case of a 78-year-old woman who presented to the Emergency Department with a 4-day history of intractable vomiting, and with no definitive clue to the diagnosis on examination. Her routine chest and abdomen x-ray studies suggested abnormal air-fluid level at right hemithorax, which prompted a computed tomography (CT) scan of the abdomen and an upper gastrointestinal contrast study. Gastric volvulus through a foramen of Morgagni was diagnosed and transthoracic reduction of the contents was performed, along with repair of the defect. A symptomatic Morgagni hernia in adults, although rare, can present with a variety of symptoms ranging from nonspecific complaints of bloating and indigestion to the more severe complaint of intestinal obstruction. Gastric volvulus and obstructive features are less frequently reported as acute complications of these hernias, which need early identification and intervention. Copyright © 2013 Elsevier Inc. All rights reserved.

Gastric Volvulus in Guinea Pigs: Comparison with Other Species

PubMed Central

Dudley, Emily S; Boivin, Gregory P

2011-01-01

Gastric volvulus has been documented in several species of animals and is associated with high morbidity and mortality. We report 2 cases of gastric volvulus in guinea pigs that died without detection of prior clinical signs. Both guinea pigs were adult female guinea pigs in a breeding colony and had given birth to multiple litters; one was pregnant at the time of death. Gastric rotations of 540° and 360° were identified at necropsy examination. These cases include the first known report of gastric rotation greater than 360° in any species. Although gastric volvulus has been reported to occur in guinea pigs, little is known about its risk factors, etiology, and pathogenesis. We conducted a literature review to compare gastric volvulus between guinea pigs and other species. PMID:21838984

[Surgical treatment of colonic volvulus. 10-year experience at the Instituto Nacional de la Nutrición Salvador Zubirán].

PubMed

Remes-Troche, J M; Pérez-Martínez, C; Rembis, V; Arch Ferrer, J; Ayala González, M; Takahashi, T

1997-01-01

To analyze morbidity-mortality and results of surgical treatment for colonic volvulus. Retrospective review of 33 patients who underwent surgical treatment for colonic volvulus from 1986 through 1996. Mean age was 62 +/- 20 years (SD) with predominance of female sex (2:1). There were 25 cases of sigmoid volvulus (76%), 7 in the cecum (21%) and 1 in the transverse colon (3%). Colonic necrosis and/or perforation were most frequently seen in the right and transverse colon (50%) than in the sigmoid (4%) (P < 0.002). Operative morbidity was 45% with mortality of 21%. Age was the only variable statistically significant for operative morbidity (52 +/- 23 years in patients without morbidity vs 71 +/- 17 years in patients with morbidity, P = 0.02). Surgical procedures for sigmoid volvulus were resection in 13 and fixation in 12. Recurrence after fixation was 38% to 12 months and 69% to 24 months (Kaplan-Meier), with associated mortality of 50%. There was no recurrence after resections. Treatment for cecal volvulus was cecopexy in 4 cases, with one recurrence; and right hemicolectomy without recurrence. The results should encourage resective procedures in sigmoid volvulus because the risk of recurrence after fixation is high and the morbidity-mortality is similar. Elderly patients are more susceptible to complications.

Acute primary mesenteroaxial gastric volvulus in a 6 years old child; the contribution of ultrasonographic findings to the prompt diagnosis (a case report and review of the literature).

PubMed

Patoulias, Dimitrios; Rafailidis, Vasileios; Kalogirou, Maria; Farmakis, Konstantinos; Rafailidis, Dimitrios; Patoulias, Ioannis

2017-01-01

The aim of the present case study is to raise concern on the proper diagnostic approach of acute gastric volvulus (AGV) cases, in which, the key issue is the timely diagnosis and the prompt therapeutic intervention. After thorough and systematic research of the current literature, it is concluded that early diagnosis remains challenging, while there is no relevant publication with emphasis on the contribution of ultrasonography to the diagnostic documentation of AGV. A 6 years old boy was admitted to our Department due to repeatedly non bilious vomiting and food refusal during the last 72 hours before admission. Physical examination revealed the presence of a spherical, painful mass in the epigastrium, which did not recede a er placement of a nasogastric tube. Abdominal radiography showed the presence of a large gastric air bubble. Ultrasonography highlighted a distended and fluid-filled stomach, which was displaced in a cephalic position compared to esophagus and a pylorus pointing downward, in a cranial caudal orientation. Following barium meal examination confirmed the diagnosis of gastric volvulus. Patient underwent an urgent exploratory laparotomy, revealing the presence of acute mesenteroaxial gastric volvulus with a serosal ecchymosis in the major arc. After restoration of the gastric volvulus, thorough intraoperative investigation on the existence of a subject cause followed. Presence of relaxation of stomach's ligaments was finally documented. Fixation of the stomach' fundus to the diaphragm and anterior gastropexy were then conducted. Postoperative period was uneventful and the patient was discharged home on the 4th postoperative day. In conclusion, we believe that ultrasonography plays a significant role in the diagnostic approach of acute gastric volvulus, as it has the potential to detect findings suggestive of the diagnosis. Once the diagnosis is suspected on ultrasonography, contrast series should be performed, without further delay, in order to con rm the diagnosis.

A case of fetal intestinal volvulus without malrotation causing severe anemia.

PubMed

Nakagawa, Tomoko; Tachibana, Daisuke; Kitada, Kohei; Kurihara, Yasushi; Terada, Hiroyuki; Koyama, Masayasu; Sakae, Yukari; Morotomi, Yoshiki; Nomura, Shiho; Saito, Mika

2015-01-01

Fetal intestinal volvulus without malrotation is a rare, life-threatening disease. Left untreated, hemorrhage from necrotic bowel tissue will lead to severe fetal anemia and even intrauterine death. We encountered a case of fetal intestinal volvulus causing severe anemia, which was diagnosed postnatally and successfully treated with surgical intervention.

A Case of Fetal Intestinal Volvulus Without Malrotation Causing Severe Anemia

PubMed Central

Nakagawa, Tomoko; Tachibana, Daisuke; Kitada, Kohei; Kurihara, Yasushi; Terada, Hiroyuki; Koyama, Masayasu; Sakae, Yukari; Morotomi, Yoshiki; Nomura, Shiho; Saito, Mika

2015-01-01

Fetal intestinal volvulus without malrotation is a rare, life-threatening disease. Left untreated, hemorrhage from necrotic bowel tissue will lead to severe fetal anemia and even intrauterine death. We encountered a case of fetal intestinal volvulus causing severe anemia, which was diagnosed postnatally and successfully treated with surgical intervention. PMID:25628516

Rearing Xyleborus volvulus (Coleoptera: Curculionidae) on Media Containing Sawdust from Avocado or Silkbay, with or without Raffaelea lauricola (Ophiostomatales: Ophiostomataceae)

USDA-ARS?s Scientific Manuscript database

Like other ambrosia beetles, Xyleborus volvulus Fabricius (Coleoptera: Curculionidae) lives in a mutualistic symbiotic relationship with fungi that serve as food source. Until recently, X. volvulus was not considered a pest, and none of its symbionts were considered plant pathogens. However, recent ...

Gastric volvulus in children--a diagnostic problem: two case reports.

PubMed

Trecroci, Ilaria; Morabito, Giuliana; Romano, Claudio; Salamone, Ignazio

2016-05-31

Gastric volvulus is a clinically significant cause of acute or recurrent abdominal pain and chronic vomiting in children. Since related clinical symptoms are nonspecific, clinicians often refer to radiologists for a diagnostic evaluation. Early diagnosis is crucial to prevent life-threatening complications of prolonged volvulus, such as intestinal ischemia, infarction, strangulation, necrosis, and perforation that may require immediate surgical treatment. In this report, we describe clinical and radiological criteria for diagnosis of gastric volvulus in children. We describe two pediatric clinical cases. A 16-month-old female Caucasian child was admitted to our hospital for recurrent postprandial vomiting episodes, which started at 11 months old, associated with failure to thrive. A 9-month-old term-born baby boy was admitted for chronic, recurrent, postprandial vomiting, which started at 7 months of age, with progressive failure to thrive. A barium study allowed definitive diagnosis of chronic organoaxial gastric volvulus. Gastric volvulus is an extremely rare disorder in the pediatric population. It can be considered a complex clinical condition with regard to the etiology and the management. A nonoperative approach is advisable in the absence of warning signs.

In utero exposure to Onchocerca volvulus: relationship to subsequent infection intensity and cellular immune responsiveness.

PubMed Central

Elson, L H; Days, A; Calvopiña, M; Paredes, W; Araujo, E; Guderian, R H; Bradley, J E; Nutman, T B

1996-01-01

Afro-Ecuadorian individuals from an area where Onchocerca volvulus is hyperendemic have been monitored for infection over the past 16 years. To determine whether in utero exposure to O. volvulus biases a child's subsequent immune responses, children (9 to 16 years old) for whom the mother's infection status was known were chosen for study. Children of infected mothers (n = 19) had significantly higher levels of skin microfilariae than children of uninfected mothers (n = 13; P = 0.021). While the serum levels of O. volvulus-specific immunoglobulin G (IgG), IgG subclasses, and IgE showed no significant differences between the two groups of children, peripheral blood mononuclear cells of children of infected mothers produced higher levels of Th2-type cytokines to several parasite antigens and lower levels of Th1-type cytokines to nonparasite antigens than those of children of uninfected mothers. Thus, in utero exposure to O. volvulus has a long-term effect on the child's subsequent cellular immune response that may render the child more susceptible to O. volvulus infection postnatally. PMID:8945547

Gastric volvulus in guinea pigs: comparison with other species.

PubMed

Dudley, Emily S; Boivin, Gregory P

2011-07-01

Gastric volvulus has been documented in several species of animals and is associated with high morbidity and mortality. We report 2 cases of gastric volvulus in guinea pigs that died without detection of prior clinical signs. Both guinea pigs were adult female guinea pigs in a breeding colony and had given birth to multiple litters; one was pregnant at the time of death. Gastric rotations of 540° and 360° were identified at necropsy examination. These cases include the first known report of gastric rotation greater than 360° in any species. Although gastric volvulus has been reported to occur in guinea pigs, little is known about its risk factors, etiology, and pathogenesis. We conducted a literature review to compare gastric volvulus between guinea pigs and other species. Copyright 2011 by the American Association for Laboratory Animal Science

Twists and turns in the body: an imaging spectrum.

PubMed

Luk, Shiobhon Y; Fung, K H

2010-10-01

Life is full of twists and turns. These surprises can sometimes be wonderfully invigorating. Twists and turns can also occur in the body, however, sometimes with dangerous consequences. Torsion and volvulus are important causes of acute abdominal pain. The clinical symptoms and signs associated with torsion and volvulus are often non-specific and are difficult to diagnose clinically. Clinicians frequently rely on imaging methods to make the diagnosis. Prompt and accurate diagnosis is important to avoid the life-threatening complications of torsion and volvulus. Therefore, it is helpful to be familiar with the features of torsion and volvulus.

Antenatal diagnosis and management of foetal intestinal volvulus.

PubMed

Yip, K W; Cheng, Y K Y; Leung, T Y

2017-04-01

In-utero intestinal volvulus is a rare but potential life threatening foetal complications. It is a surgical emergency and delay in diagnosis or treatment can increase the morbidity and mortality to the foetus. We report a case of mild foetal bowel dilatation diagnosed at 21 weeks of gestation. She was closely follow up and at 31 weeks of gestation, in-utero intestinal volvulus was diagnosed with the characteristic 'whirlpool' sign on ultrasound examination. This case emphasises the importance of early recognition and quick decision to delivery when intestinal volvulus is diagnosed. This enabled early surgical intervention to prevent further foetal morbidity.

Prenatal intestinal volvulus: look for cystic fibrosis.

PubMed

Chouikh, Taieb; Mottet, Nicolas; Cabrol, Christelle; Chaussy, Yann

2016-12-21

Intestinal volvulus is a life-threatening emergency requiring prompt surgical management. Prenatal intestinal volvulus is rare, and most are secondary to intestinal atresia, mesenteric defect or without any underlying cause. Cystic fibrosis (CF) is known to cause digestive tract disorders. After birth, 10-15% of newborns with CF may develop intestinal obstruction within a few days of birth because of meconial ileus. 1 This obstruction is a result of dehydrated thickened meconium obstructing the intestinal lumen. We report two cases of fetuses with prenatal diagnosis of segmental volvulus in whom CF was diagnosed. 2016 BMJ Publishing Group Ltd.

Intestinal Rotation Abnormalities and Midgut Volvulus.

PubMed

Langer, Jacob C

2017-02-01

Rotation abnormalities may be asymptomatic or may be associated with obstruction caused by bands, midgut volvulus, or associated atresia or web. The most important goal of clinicians is to determine whether the patient has midgut volvulus with intestinal ischemia, in which case an emergency laparotomy should be done. If the patient is not acutely ill, the next goal is to determine whether the patient has a narrow-based small bowel mesentery. In general, the outcomes for children with a rotation abnormality are excellent, unless there has been midgut volvulus with significant intestinal ischemia. Copyright © 2016 Elsevier Inc. All rights reserved.

Chronic mesenteric volvulus in a dog

PubMed Central

Spevakow, Andrea B.; Nibblett, Belle Marie D.; Carr, Anthony P.; Linn, Kathleen A.

2010-01-01

A chronic, partial mesenteric volvulus was found on laparotomy of an adult Bernese mountain dog with a 4-month history of intermittent vomiting, diarrhea, and weight loss. The dog had elevated cholestatic and hepatocellular leakage enzymes, increased bile acids, azotemia, isosthenuria, and a hypokalemic, hypochloremic, metabolic alkalosis. The dog recovered fully following reduction of the volvulus. PMID:20357947

Rearing Xyleborus volvulus (Coleoptera: Curculionidae) on Media Containing Sawdust from Avocado or Silkbay, With or Without Raffaelea lauricola (Ophiostomatales: Ophiostomataceae).

PubMed

Menocal, Octavio; Cruz, Luisa F; Kendra, Paul E; Crane, Jonathan H; Ploetz, Randy C; Carrillo, Daniel

2017-12-08

Like other ambrosia beetles, Xyleborus volvulus Fabricius (Coleoptera: Curculionidae) lives in a mutualistic symbiotic relationship with fungi that serve as food source. Until recently, X. volvulus was not considered a pest, and none of its symbionts were considered plant pathogens. However, recent reports of an association between X. volvulus and Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva (Ophiostomatales: Ophiostomataceae), the cause of the laurel wilt disease of avocado (Persea americana Mill. [Laurales: Lauraceae]), and its potential role as vector of the pathogen merit further investigation. The objective of this study was to evaluate three artificial media containing sawdust obtained from avocado or silkbay (Persea humilis Nash) for laboratory rearing of X. volvulus. The effect of R. lauricola in the media on the beetle's reproduction was also evaluated. Of the three media, the one with the lowest content of sawdust and intermediate water content provided the best conditions for rearing X. volvulus. Reproduction on this medium was not affected by the sawdust species or the presence of R. lauricola. On the other two media, there was a significant interaction between sawdust species and R. lauricola. The presence of R. lauricola generally had a negative effect on brood production. There was limited colonization of the mycangia of X. volvulus by R. lauricola on media inoculated with the pathogen. From galleries formed within the best medium, there was 50% recovery of R. lauricola, but recovery was much less from the other two media. Here, we report the best artificial substrate currently known for X. volvulus. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

[Volvulus of the cecum: a rare cause of intestinal occlusion: about two cases].

PubMed

Mazine, Khalid; Elbouhaddouti, Hicham; Toughrai, Imane; Mouaqit, Ouadie; Benjelloun, Elbachir; Ousadden, Abdelmalek; Taleb, Khalid Ait

2017-01-01

The cecum is the second part of the colon that is most commonly affected by the volvulus after sigmoid colon and before left corner and the transverse colon. This condition occurs in patients with abnormally mobile cecum. Volvulus is characterized by torsion or tilt. Clinically, it appears as bowel obstruction due to acute strangulation. Abdominal x-ray without treatment and abdominal CT scan are the radiological procedures of choice in the diagnosis of volvulus of the cecum. Treatment is based on emergency surgical excision of the cecum and of the terminal ileum. We report two cases of patients with volvulus of the cecum admitted to the emergency department with acute intestinal obstruction. In both patients, the diagnosis was confirmed by abdomino-pelvic CT scan and the treatment was based on ileocolic resection with immediate restoration of the intestinal continuity. The postoperative course was uneventful.

Caecal volvulus in a patient with chronic intestinal pseudo-obstruction

PubMed Central

El-Khatib, C

2011-01-01

Chronic intestinal pseudo-obstruction (CIPO) is a rare disorder characterised by recurrent symptoms and signs of intestinal obstruction without an underlying mechanical cause. Caecal volvulus remains a rare cause of intestinal obstruction that often requires operative intervention. We describe the previously unreported case of caecal volvulus occurring in an adult patient with CIPO, together with his subsequent management. PMID:22004621

Acute Organoaxial gastric volvulus: A massive problem with a twist-case report.

PubMed

Al Daoud, Fadi; Daswani, Gul Sachwani; Perinjelil, Vinu; Nigam, Tina

2017-01-01

Gastric volvulus (GV) is a rare and life threatening condition if not treated promptly or wrongly diagnosed. The main complication of gastric volvulus is foregut obstruction. The extreme rotation can cut off blood supply to the stomach and even distal organs, which can lead to ischemia and necrosis of the affected area. We report a case of a 41yo female that complained of severe abdominal pain, nausea and vomiting for approximately 3days after eating a large meal. The patient didn't have any flatus or bowel movements in the last 24h. CT of the abdomen and pelvis showed a dilatation of the stomach and esophageal hernia. Laparotomy confirmed an organoaxial volvulus at the level of the antrum and body of the stomach. Gastropexy was implemented and the stomach fixed to the posterior abdominal wall to prevent recurrence. GV may have a significant related morbidity and mortality rate. It can be missed easily on diagnosis. The presence of vomiting not responding to initial antiemetic treatment, as well as, the presence of a hiatal hernia on the imaging studies should trigger our thinking of gastric volvulus, regardless of the stable appearance of the patient. Chronic GV can manifests as atypical chest, abdomen and gastro intestinal symptoms. We recommend that everyone with these atypical symptoms seek medical attention to rule out GV. Early diagnosis and treatment will reduce the risk of developing chronic gastric volvulus to acute gastric volvulus. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

The threatened stomach: management of the acute gastric volvulus.

PubMed

Light, D; Links, D; Griffin, M

2016-05-01

Acute presentation of gastric volvulus is a rare condition with a high mortality for acute ischaemia. This study was undertaken to investigate the acute management, diagnosis, and long-term outcomes of patients presenting with acute gastric volvulus. Cases were reviewed retrospectively from 2004 to 2014. Patients presenting as an emergency admission with acute gastric volvulus were included. Thirty-six patients were included, five of whom had previous surgery. The mean age was 71 years old. All patients presented with vomiting and chest/epigastric pain. CT was diagnostic in all 26 patients. Barium swallow was diagnostic in two/four patients. OGD was diagnostic in 9 of 20 patients. All patients had an NG tube placed, and eight patients were treated conservatively and made a full recovery. Twenty-nine patients proceeded to surgery. Nine had a laparoscopic repair with two open conversions. Four patients had gastric necrosis, and all had open surgery with resection. Three patients had a mediastinal perforation, and one patient required an additional thoracotomy. All patients with viable stomach had a hiatal repair (where appropriate), 11 had a gastropexy, and 11 had a fundoplication. Mortality for gastric necrosis/perforation was 30 %. Mean postoperative stay was 4 days for laparoscopic repair and 8 days for uncomplicated open surgery. Nine of twenty-nine had transient dysphagia postoperatively. Three of eight patients treated conservatively had an elective procedure subsequently. Acute paraoesophageal hiatus hernia requires early resuscitation and diagnosis. CT should be favoured in assessment, and an NG tube placed promptly. A conservative management may be considered safely in stable patients. Surgical management should be prompt for unstable patients. Gastric ischaemia or perforation has a mortality of 30 %. Laparoscopic repair has a shorter postoperative stay, but has a higher recurrence rate. Surgery for patients without gastric ischaemia has good long-term outcomes with minimal morbidity.

Laparoscopic diagnosis of magnetic malrotation with fistula and volvulus.

PubMed

Wooten, Kimberly E; Hartin, Charles W; Ozgediz, Doruk E

2012-01-01

Most foreign bodies that a child ingests pass harmlessly through the gastrointestinal tract. However, ingesting multiple magnets places a child at risk for serious viscus injury. A 16-y-old boy swallowed multiple magnets and presented with abdominal pain and emesis. Upon laparoscopy, the boy was found to have malrotation with volvulus caused by a cecal magnet attracted to a gastric magnet, resulting in a gastrocecal fistula. We review the management of magnet ingestion with an emphasis on a high index of suspicion and the use of laparoscopy for diagnosis, as well as the consequences of a coexisting rotational anomaly.

Intestinal volvulus and perforation caused by multiple magnet ingestion: report of a case.

PubMed

Ilçe, Zekeriya; Samsum, Hakan; Mammadov, Emil; Celayir, Sinan

2007-01-01

Ingested magnets can cause intestinal fistulas, perforation, and obstruction. There have been reports of magnet ingestion causing intestinal volvulus, but multiple magnet ingestion causing perforation and intestinal volvulus in a child is very unusual. We report the case of a 4-year-old girl, who ingested four magnets she acquired as toys, which caused intestinal volvulus and perforation as a result of pressure necrosis, several days after ingestion. At surgery we repaired two perforations, but additional bowel resection was not required. The patient was discharged on postoperative day 10. If multiple magnet ingestion is suspected in a child, the child must be monitored carefully. If there are signs of obstruction, emergency surgery is mandatory.

Effect of electrospun nanofibers on flexural properties of fiberglass composites

NASA Astrophysics Data System (ADS)

White, Fatima T.

In the present study, sintered electrospun TEOS nanofibers were interleaved in S2 fiberglass woven fabric layers, and composite panels were fabricated using the heated vacuum assisted resin transfer molding (H-VARTM) process. Cured panels were water jet cut to obtain the flexural test coupons. Flexural coupons were then tested using ASTM D7264 standard. The mechanical properties such as flexural strength, ultimate flexural failure strains, flexural modulus, and fiber volume fraction were measured. The S-2 fiberglass composite with the sintered TEOS electrospun nanofibers displayed lower flexural stiffness and strength as compared to the composites that were fabricated using S-2 fiberglass composite without the TEOS electrospun nanofibers. The present study also indicated that the composites fabricated with sintered TEOS electrospun nanofibers have larger failure strains as compared to the ones that were fabricated without the presence of electrospun nanofibers. The study indicates that the nanoengineered composites have better energy absorbing mechanism under flexural loading as compared to conventional fiberglass composites without presence of nanofibers.

[Elective laparoscopic right colectomy for caecal volvulus: case report and literature review].

PubMed

Ramírez-Ramírez, Moisés Marino; Villanueva-Sáenz, Eduardo; Ramírez-Wiella-Schwuchow, Gustavo

Caecal volvulus is an uncommon cause of intestinal obstruction. Its clinical presentation is non-specific, with the diagnosis usually confirmed by barium enema and abdominal computed tomography. Treatment depends on many factors, and minimally invasive approaches are becoming the treatment of choice. A 54 years old female, admitted to the Emergency Department with clinical symptoms of intestinal obstruction. On physical examination she had a palpable, firm, and tympanitic mass in the right abdomen, with peritoneal irritation. The radiographs of the abdomen, barium enema and abdominal computed tomography showed caecal volvulus. As she showed a full remission after the barium enema, with no clinical or biochemical data of systemic inflammatory response syndrome or peritoneal irritation, she was discharged to her home. Two weeks later, a laparoscopic right hemicolectomy was performed with an ileo-transverse extracorporeal anastomosis. Her progress was satisfactory, and she was discharged 4 days after surgery due to improvement. Caecal volvulus is a rare cause of intestinal obstruction, with high mortality rates, and is caused by excessive mobility of the caecum. Its incidence is increasing. Treatment depends on many factors. Early non-surgical untwisting, followed by an elective laparoscopic surgical procedure offers several advantages and reduces mortality. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

Incidence of gastric dilatation-volvulus following a splenectomy in 238 dogs.

PubMed

Maki, Lynn C; Males, Kristina N; Byrnes, Madeline J; El-Saad, Anthony A; Coronado, George S

2017-12-01

There is contradicting information in the veterinary literature regarding canine splenectomy and the increased risk for subsequent gastric dilatation-volvulus. The main purpose of this study was to determine the rate of occurrence of gastric dilatation-volvulus following splenectomy in medium to large breed dogs compared with a control group undergoing other abdominal procedures. Follow-up was performed by reviewing the medical records and conducting phone interviews. Weight, gender, and presence of a hemoabdomen at the time of surgery were not significantly associated with occurrence of gastric dilatation-volvulus, while increasing age was. Ten of 238 (4%) dogs in the splenectomy group and 3/209 (1.4%) dogs in the control group subsequently developed gastric dilatation-volvulus, which was not significantly different ( P = 0.08). While the findings approach significance and support a need for future investigation, the current recommendation for gastropexy at time of splenic removal should be made on a case by case basis and while considering previously documented risk factors.

Large-scale entomologic assessment of Onchocerca volvulus transmission by poolscreen PCR in Mexico.

PubMed

Rodríguez-Pérez, Mario A; Katholi, Charles R; Hassan, Hassan K; Unnasch, Thomas R

2006-06-01

To study the impact of mass Mectizan treatment on Onchocerca volvulus transmission in Mexico, entomological surveys were carried out in the endemic foci of Oaxaca, Southern Chiapas, and Northern Chiapas. Collected flies were screened by polymerase chain reaction (PCR) for O. volvulus parasites. The prevalence of infected and infective flies was estimated using the PoolScreen algorithm and with a novel probability-based method. O. volvulus infective larvae were not detected in flies from 6/13 communities. In 7/13 communities, infective flies were detected, with prevalences ranging from 1.6/10,000 to 29.0/10,000 and seasonal transmission potentials ranging from 0.4 to 3.3. Infected and infective flies were found in a community in Northern Chiapas, suggesting that, according to World Health Organization criteria, autochthonous transmission exists in this focus. These data suggest that O. volvulus transmission in Mexico has been suppressed or brought to a level that may be insufficient to sustain the parasite population.

The risk of volvulus in abdominal wall defects.

PubMed

Abdelhafeez, Abdelhafeez H; Schultz, Jessica A; Ertl, Allison; Cassidy, Laura D; Wagner, Amy J

2015-04-01

Congenital abdominal wall defects are associated with abnormal intestinal rotation and fixation. A Ladd's procedure is not routinely performed in these patients; it is believed intestinal fixation is provided by adhesions that develop post-repair of the defects. However, patients with omphalocele may not have adequately protective postoperative adhesions because of difference in the inflammatory state of the bowel wall and in repair strategy. The aim of this study is to describe the occurrence of midgut volvulus in patients with gastroschisis or omphalocele. A retrospective chart review was performed for all patients managed in a single institution born between 1/1/2000 and 12/31/2008 with a diagnosis of gastroschisis or omphalocele. Patient charts were reviewed through 12/31/2012 for occurrence of midgut volvulus or need for second laparotomy. Of the 206 patients identified with abdominal wall defects, 142 patients (69%) had gastroschisis and 64 patients (31%) had omphalocele. Patients' follow up ranged from 4 years to 13 years. The median gestational age was 36 weeks (26-41 weeks) and the median birth weight was 2.42 kg (0.8-4.87 kg). None of the patients with gastroschisis developed midgut volvulus, however two patients (3%) with omphalocele developed midgut volvulus. No patients with gastroschisis developed midgut volvulus. Therefore, the current practice of not routinely performing a Ladd's procedure is a safe approach during surgical repair of gastroschisis. The two cases of volvulus in patients with omphalocele may be related to less bowel fixation. It is necessary to examine current practice in regards to the need for assessing the risk of volvulus during omphalocele closure and counseling of these patients. This assessment may be achieved via routine examination of the width of the small bowel mesenteric base, whenever feasible; however, the sample size is relatively small to draw any definitive conclusions. Published by Elsevier Inc.

Rare small intestinal volvulus from entrapment in hepato-diaphragmatic adhesions in a 45-year-old lady

PubMed Central

Olaoye, Iyiade Olatunde; Adesina, Micheal Dapo

2016-01-01

Small intestinal volvulus is rare in adults and rarely caused by string adhesions between the liver and the diaphragm. Similar adhesions were described in Fitz-Hugh-Curtis syndrome. We report a 45-year-old lady with small intestinal volvulus from entrapment of a loop in string adhesions between the liver and the diaphragm. Her plain radiographs showed a significant shadow of the trapped loop. PMID:28003317

Small intestinal volvulus in a free-ranging female dugong (Dugong dugon).

PubMed

Gillespie, A; Burgess, E; Lanyon, J; Owen, H

2011-07-01

An adult female dugong (Dugong dugon) was found dead and floating in Moreton Bay, Queensland, Australia. This animal was found to have a 360° mesenteric volvulus with infarction of the associated segment of small intestine, and fibrinous peritonitis. Mortality was attributed to the volvulus and its sequelae. The cause was not apparent on gross or histological examination. © 2011 The Authors. Australian Veterinary Journal © 2011 Australian Veterinary Association.

Design and experimental characterization of flexure activated by SMA wires for microassembly operations

NASA Astrophysics Data System (ADS)

Flores, Abiud; Ahuett, Horacio; Song, Gangbing

2006-03-01

Compliant mechanisms have a wide range of application in microassembly, micromanipulation and microsurgery. This article presents a low cost Flexure-Stage actuated by two SMA-wires that produces displacement in one direction in a range from 0 to 10 μm. The Flexure-Stage acts as a mechanical transform by reducing and changing the direction of the SMA actuator output displacement. The Flexure-Stage system has its application in microassembly operation and was built at cost of US$ 35 cost. The design methodology of a flexure-stage from concept design through FEA modeling and finally to construction and characterization is presented in this paper.

Resection and primary anastomosis with or without modified blow-hole colostomy for sigmoid volvulus

PubMed Central

Coban, Sacid; Yilmaz, Mehmet; Terzi, Alpaslan; Yildiz, Fahrettin; Ozgor, Dincer; Ara, Cengiz; Yologlu, Saim; Kirimlioglu, Vedat

2008-01-01

AIM: To evaluate the efficacy of resection and primary anastomosis (RPA) and RPA with modified blow-hole colostomy for sigmoid volvulus. METHODS: From March 2000 to September 2007, 77 patients with acute sigmoid volvulus were treated. A total of 47 patients underwent RPA or RPA with modified blow-hole colostomy. Twenty-five patients received RPA (Group A), and the remaining 22 patients had RPA with modified blow-hole colostomy (Group B). The clinical course and postoperative complications of the two groups were compared. RESULTS: The mean hospital stay, wound infection and mortality did not differ significantly between the groups. Superficial wound infection rate was higher in group A (32% vs 9.1%). Anastomotic leakage was observed only in group A, with a rate of 6.3%. The difference was numerically impressive but was statistically not significant. CONCLUSION: RPA with modified blow-hole colostomy provides satisfactory results. It is easy to perform and may become a method of choice in patients with sigmoid volvulus. Further studies are required to further establish its role in the treatment of sigmoid volvulus. PMID:18810779

[The significance of electronic CTG for intrauterine volvulus in the 32nd week of gestation].

PubMed

Schiermeier, S; Reinhard, J; Westhof, G; Hatzmann, W

2008-02-01

Intrauterine intestinal volvulus is a difficult diagnosis to make, but has life-threatening implications for the fetus. We present a case of vulvulus without malrotation in a single fetus revealed in the 32nd gestation week in a 44-year-old woman. The presenting complaint of this patient was reduced fetal movements. Ultrasound examination showed a normal result except for a dilated stomach. Doppler ultrasound results were within the normal range. Computed cardiotocography (CTG) showed pathological results for acceleration and suspect values for variability. Short-term variability (STV) was at 2.80 ms. Due to the pathological computed CTG results a Caesarian section was carried out. The newborn received prompt postnatal surgical treatment and continues to be in good overall condition.

Determination of the acid-base status in 50 horses admitted with colic between December 1998 and May 1999.

PubMed Central

Nappert, G; Johnson, P J

2001-01-01

The purpose of the present study was to investigate the acid-base status and the concentration of organic acids in horses with colic caused by various disorders. Blood samples were collected from 50 horses with colic and from 20 controls. No intravenous fluids had been given prior to sample collection. Identified causes of colic included gastric ulceration, small intestinal volvulus, cecal intussusception, cecal rupture, colonic impaction, left dorsal colon displacement, right dorsal colon displacement, colonic volvulus, colitis, peritonitis, and uterine torsion. Thirty-seven horses recovered from treatment of colic, 8 horses were euthanized, and 5 died. Most cases were not in severe metabolic acidosis. In previous studies, most horses presented for diagnosis and treatment of colic were in metabolic acidosis and in shock. PMID:11565369

The relationship between fibre post geometry and flexural properties: an assessment through a modified three-point bending test.

PubMed

Soares, L P; de Vasconcellos, A B; da Silva, A H Monteiro da Fonseca Thomé; Sampaio, E M; Vianna, G A de Deus Carneiro

2010-12-01

The aim of this study was to investigate the flexural properties of five types of fiber-reinforced dowels using a modified three-point bending test. Fiber-reinforced resin dowels were tested by a modified three-point bending test associated with models for cylindrical and conical simple-supported beams. The fracture load ranged from 86 to 246 N and the flexural strength from 423 to 1192 MPa. FRC Postec had significantly higher flexural strength and fracture loads values. Thus, the present study demonstrated higher flexural strength values for the FRC Postec fibre posts, suggesting that this system would present a better response to the forces of mastication.

Onchocerciasis in Venezuela: prevalence of microfilaraemia in Amerindians and morphological characteristics of the microfilariae from the Upper Orinoco Focus.

PubMed

Botto, C; Arango, M; Yarzábal, L

1984-09-01

Data are presented on microfilaraemia in 191 Yanomami Amerindians from two areas of Venezuela's Upper Orinoco Basin, where an endemic focus of onchocerciasis has been recently detected. Onchocerca microfilariae were found in the blood of 12.6% of the persons examined. In the village with the higher number of examined individuals (N = 162), the prevalence of microfilaraemia in the age groups covaried with the prevalence of microfilariae in the skin and with the parasite load (mf/mg of skin). A positive correlation was found between age and these three variables. The prevalence of Onchocerca microfilaraemia in the Upper Orinoco focus is high, and may be related to the ability of the strain to invade the blood stream. Morphobiometric characteristics of the Onchocerca microfilariae isolated from human blood are similar to those of O. volvulus fixed in formalin from skin and from the uterus of female O. volvulus worms. All have a very short cephalic space. Comparisons with the entity from the Upper Caura river designated as Microfilaria bolivarensis were also made. It was concluded that there are no valid biometric differences in thick blood smears between microfilaria bolivarensis and microfilaria of O. volvulus from the Upper Orinoco deme. A more striking difference may be in the concentration of microfilariae observed in the blood, which in one case of mf. bolivarensis was more than forty times the highest number recorded for microfilaria O. volvulus in Parima.

Colonic or ileocecocolic volvulus in 13 dogs (2005-2016).

PubMed

Plavec, Tanja; Rupp, Stefan; Kessler, Martin

2017-08-01

To describe the clinical and clinicopathological features of colonic or ileocecocolic volvulus (CV/ICV) in dogs. Retrospective case series. Thirteen dogs with surgically confirmed CV/ICV. Medical records were reviewed for signalment, medical history, clinical signs, laboratory data, radiographic findings, treatment, and outcome. All cases consisted of large-breed dogs (median weight 37.1 kg, range, 22.7-58.5 kg), 8 of these male (6 intact). The most common clinical signs included vomiting, depression, inappetence, and diarrhea with or without tenesmus. All cases presented in shock with abdominal distension, abdominal pain, or both. Dogs were treated for shock and operated immediately after a presumptive diagnosis was based on clinical and radiographic examinations. Three dogs were euthanatized during surgery, 10 dogs were discharged live from the hospital, 9 of these were alive at follow-up 6 to 70 months (median 24 months) after surgery. CV and ICV are rare disorders that seem to carry a better prognosis than mesenteric volvulus. Immediate laparotomy is recommended in suspected cases and the prognosis is fair. © 2017 The American College of Veterinary Surgeons.

Laparoscopic Repair of Intrathoracic Stomach: Clinical and Health-related Quality of Life Outcomes.

PubMed

Karim, Muhammad A; Maloney, Jay; Ali, AbdulMajid

2016-12-01

This study aims to evaluate the clinical and quality of health outcomes in patients undergoing laparoscopic repair of intrathoracic stomach with or without gastric volvulus. From January 2007 to December 2013, a prospectively maintained data, of patients undergoing surgical repair of intrathoracic stomach, with or without gastric volvulus, was reviewed. Patient demographics, ASA grade, diagnostic technique, semiurgent/emergency status, type of volvulus if present, details of surgery and perioperative complications were recorded. Validated SF-36 questionnaires were completed by patients to record preoperative and postoperative quality of life (QoL) status. Patients managed by nonoperative measures were excluded from the study. Thirty patients were identified with intrathoracic stomach. Fourteen patients had gastric volvulus. Twenty-seven patients (10 emergency, 17 semiurgent) underwent laparoscopic repair of intrathoracic stomach and were included in the study. Mean operating time was 156 (SD, 37.5; range, 105 to 230) minutes. All 27 operations were completed by laparoscopic approach. There was no conversion to open procedure or mortality at 30 days. Mean hospital stay was 5.2 (range, 1 to 15) days. There were 3 (11%) early postoperative complications. One (3.7%) patient developed recurrence at 2 years which required reoperation. Mean follow-up was 10.5 (range, 1 to 36) months. ASA grade and operative time determined the postoperative hospital stay (P=0.001, 0.001, respectively), whereas body mass index and age were shown to have no influence. Patient-reported QoL scores improved across all scales of the health questionnaire after surgery especially bodily pain, social functioning, and physical functioning. Laparoscopic surgery is a safe and effective treatment option for intrathoracic stomach, with or without gastric volvulus. It is associated with low rates of complications and recurrence. Self-reported patient data shows significant improvement to overall QoL after surgery for intrathoracic stomach.

Small bowel volvulus due to torsion of pedunculated uterine leiomyoma: CT findings.

PubMed

Guglielmo, Nicola; Malgras, Brice; Place, Vinciane; Guerrache, Youcef; Pautrat, Karine; Pocard, Marc; Soyer, Philippe

Torsion of a uterine leiomyoma is a rare complication that can be life threatening because of ischemia or necrosis. This condition may also lead to gastrointestinal complications such as obstruction or, more rarely, small bowel volvulus. Its diagnosis is difficult and can be facilitated with the use of computed tomography or magnetic resonance imaging. Treatment is based on emergency surgical resection of the twisted uterine leiomyoma and detorsion of the small bowel volvulus. Copyright © 2016 Elsevier Inc. All rights reserved.

Emergence of Onchocerca volvulus from Skin Mimicking Dracunculiasis medinensis

PubMed Central

Eberhard, Mark L.; Ruiz-Tiben, Ernesto; Korkor, Andrew S.; Roy, Sharon L.; Downs, Philip

2010-01-01

We describe 11 cases of suspected Dracunculus medinensis infection in which the worm recovered was identified as Onchocerca volvulus. Identification was based on morphology of the examined specimen. PMID:21118947

Segmental dilatation of the ileum covered almost entirely by gastric mucosa: report of a case.

PubMed

Kobayashi, Tsutomu; Uchida, Nobuyuki; Shiojima, Masayuki; Sasamoto, Hajime; Shimura, Tatsuo; Takahasi, Atsusi; Kuwano, Hiroyuki

2007-01-01

A 13-year-old boy was referred to our hospital for investigation of intermittent abdominal colic pain and vomiting. He underwent an emergency laparotomy, which revealed a volvulus and segmental dilatation of the ileum. The dilated intestine was not associated with poor intestinal circulation. Because the dilated ileum did not seem to be the cause of the volvulus, we simply released the volvulus. However, after surgery, the patient still suffered from persistent abdominal pain, further episodes of volvulus, and invagination of the dilated ileum. Thus, we performed a second operation to resect the segmental dilatation of the ileum. Pathological examination revealed that most of the mucosa of the dilated ileum was composed of ectopic gastric mucosa. We postulate that the ectopic gastric mucosa led to the formation of segmental dilatation of the ileum.

Diagnosis of a sigmoid volvulus in pregnancy: ultrasonography and magnetic resonance imaging findings

PubMed Central

Palmucci, Stefano; Lanza, Maria Letizia; Gulino, Fabrizio; Scilletta, Beniamino; Ettorre, Giovanni Carlo

2014-01-01

Sigmoid volvulus complicating pregnancy is a rare, non-obstetric cause of abdominal pain that requires prompt surgical intervention (decompression) to avoid intestinal ischemia and perforation. We report the case of a 31-week pregnant woman with abdominal pain and subsequent development of constipation. Preoperative diagnosis was achieved using magnetic resonance imaging and ultrasonography: the large bowel distension and a typical whirl sign - near a sigmoid colon transition point - suggested the diagnosis of sigmoid volvulus. The decision to refer the patient for emergency laparotomy was adopted without any ionizing radiation exposure, and the pre-operative diagnosis was confirmed after surgery. Imaging features of sigmoid volvulus and differential diagnosis from other non-obstetric abdominal emergencies in pregnancy are discussed in our report, with special emphasis on the diagnostic capabilities of ultrasonography and magnetic resonance imaging. PMID:24967020

Diagnosis of a sigmoid volvulus in pregnancy: ultrasonography and magnetic resonance imaging findings.

PubMed

Palmucci, Stefano; Lanza, Maria Letizia; Gulino, Fabrizio; Scilletta, Beniamino; Ettorre, Giovanni Carlo

2014-02-01

Sigmoid volvulus complicating pregnancy is a rare, non-obstetric cause of abdominal pain that requires prompt surgical intervention (decompression) to avoid intestinal ischemia and perforation. We report the case of a 31-week pregnant woman with abdominal pain and subsequent development of constipation. Preoperative diagnosis was achieved using magnetic resonance imaging and ultrasonography: the large bowel distension and a typical whirl sign - near a sigmoid colon transition point - suggested the diagnosis of sigmoid volvulus. The decision to refer the patient for emergency laparotomy was adopted without any ionizing radiation exposure, and the pre-operative diagnosis was confirmed after surgery. Imaging features of sigmoid volvulus and differential diagnosis from other non-obstetric abdominal emergencies in pregnancy are discussed in our report, with special emphasis on the diagnostic capabilities of ultrasonography and magnetic resonance imaging.

Percutaneous Endoscopic Colostomy: A New Technique for the Treatment of Recurrent Sigmoid Volvulus

PubMed Central

Al-Alawi, Ibrahim K.

2010-01-01

Sigmoid volvulus is a common cause of large bowel obstruction in western countries and Africa. It accounts for 25% of the patients admitted to the hospital for large bowel obstruction. The acute management of sigmoid volvulus is sigmoidoscopic decompression. However, the recurrence rate can be as high as 60% in some series. Recurrent sigmoid volvulus in elderly patients who are not fit for definitive surgery is difficult to manage. The percutaneous endoscopic placement of two percutaneous endoscopic colostomy tube placement is a simple and relatively safe procedure. The two tubes should be left open to act as vents for the colon from over-distending. In our opinion, this aspect is key to its success as it keeps the sigmoid colon deflated until adhesions form between the colon and the abdominal wall. PMID:20339184

Gastric dilatation volvulus: a retrospective study of 203 dogs with ventral midline gastropexy.

PubMed

Ullmann, B; Seehaus, N; Hungerbühler, S; Meyer-Lindenberg, A

2016-01-01

To evaluate the recurrence rate of gastric dilatation volvulus and the incidence of complications in subsequent coeliotomies following ventral midline gastropexy. The medical records of dogs treated for gastric dilatation volvulus by ventral midline gastropexy were retrospectively reviewed. Owners were contacted and invited to complete a questionnaire and to return to the clinic for ultrasonographic and radiographic follow-up. The questionnaire was completed by 203 owners 2 to 123 months postoperatively, 24 of whom attended the follow-up examination. Of the 203 dogs, 13 (6 · 4%) underwent subsequent ventral midline coeliotomy and none developed complications related to the gastropexy site. In 23 of the 24 re-evaluated dogs, the stomach was closely associated with the abdominal on radiography and/or ultrasound. The recurrence rate for clinical signs of gastric dilatation or gastric dilatation volvulus after ventral midline gastropexy was 6 · 4%. This study shows that the recurrence of gastric dilatation volvulus after ventral midline gastropexy is low and adhesion of the stomach to the abdominal wall is persistent in almost all dogs that were re-examined. The gastropexy site did not appear to interfere with subsequent coeliotomy. © 2015 British Small Animal Veterinary Association.

Fetal midgut volvulus: report of eight cases.

PubMed

Sciarrone, A; Teruzzi, E; Pertusio, A; Bastonero, S; Errante, G; Todros, T; Viora, E

2016-01-01

To evaluate whether prenatal diagnosis of intestinal midgut volvulus (a rare condition due to the small bowel loops twisting) can improve the prognosis of the newborns. In our Prenatal Diagnosis Center, eight cases of intestinal volvulus observed between 2007 and 2014 were retrospectively considered. Ultrasonographic signs can be direct and specific (whirlpool sign, coffee bean sign) or indirect and non-specific (abdominal mass, dilated bowel loops, pseudocysts, ascites, polyhydramnios). Prenatal diagnosis was performed at 20-34 weeks of gestation. All newborns were exposed to an emergency surgery: the major complication was due to cystic fibrosis. An early suspicion of intestinal volvulus allows the clinician to refer the patient to a tertiary center so to confirm the diagnosis and perform an appropriate follow-up in order to identify the proper time of delivery. The prognosis of the babies with prenatal intestinal volvulus depends on the length of the segment involved, on the level of intestinal obstruction, on the presence of meconium peritonitis and on the gestational age at birth. Our experience, according with the literature, suggests that ascites and absence of abdominal peristalsis are ultrasonographic signs that, in the third trimester of pregnancy, correctly lead to an immediate delivery intervention.

Torsion and volvulus of the transverse and descending colon in a German shepherd dog.

PubMed

Halfacree, Z J; Beck, A L; Lee, K C L; Lipscomb, V J

2006-08-01

A German shepherd dog was presented two months after surgery for correction of acute gastric dilatation volvulus. The dog had been diagnosed with exocrine pancreatic insufficiency. Radiographs revealed marked gaseous distension of one loop of intestine with a generalised increase in intestinal gas content. A 360 degrees anticlockwise rotation of the descending and transverse colon, around the longitudinal axis of the mesocolon, was diagnosed at exploratory coeliotomy. The transverse and descending colon appeared uniformly necrotic and an end-to-end colo-colic resection and anastomosis was performed. The dog initially made satisfactory postoperative progress but was euthanased on the third postoperative day after it developed an intestinal intussusception.

[Urgent surgical treatment of gastric volvulus related to upside-down stomach syndrome].

PubMed

Hána, L; Kasalický, M; Koblihová, E; Suchánek, Š; Horažďovský, P; Ryska, M

2015-12-01

Upside-down stomach syndrome is a rare type of a large paraoesophageal hiatal hernia, which requires an immediate surgical treatment in case of incarceration. The authors present a case report of a 53-year-old male patient with gastric volvulus related to the upside-down stomach syndrome. Surgical treatment was complicated by an injury to distal oesophagus, which was successfully treated using a self-expandable metallic stent among other methods. Despite the complicated postoperative course with a necessity of reoperation, insertion of an oesophageal stent, thoracotomy for a mediastinal abscess and secondary healing of the laparotomy, the patient was discharged in a good condition with healed oesophageal perforation and laparotomy after 52 days.

Gastric Dilitation-Volvulus in a Red Panda (Ailurus fulgens)

PubMed Central

SCHLANSER, Justin R.; AGNEW, Dalen; PAPERD, Deborah W.; HARRISON, Tara M.

2014-01-01

ABSTRACT A 10-year-old male red panda presented acutely with symptoms of shock due to acute abdominal distress and respiratory compromise. Abdominal ultrasound confirmed a severely distended stomach for which passage of an orogastric tube for relief was unsuccessful. Intra-operatively, the stomach was found to be distended and torsed around its long axis supporting the diagnosis of Gastric dilitation-volvulus (GDV). The animal arrested and died intra-operatively and was submitted for necropsy with lesions supportive of the diagnosis of GDV. No risk factors for GDV were found to correlate between the panda and those described in domestic dogs. This case suggests that red pandas can be susceptible to this condition in captive settings. PMID:24521795

Gastric dilitation-volvulus in a Red Panda (Ailurus fulgens).

PubMed

Schlanser, Justin R; Agnew, Dalen; Paperd, Deborah W; Harrison, Tara M

2014-06-01

A 10-year-old male red panda presented acutely with symptoms of shock due to acute abdominal distress and respiratory compromise. Abdominal ultrasound confirmed a severely distended stomach for which passage of an orogastric tube for relief was unsuccessful. Intra-operatively, the stomach was found to be distended and torsed around its long axis supporting the diagnosis of Gastric dilitation-volvulus (GDV). The animal arrested and died intra-operatively and was submitted for necropsy with lesions supportive of the diagnosis of GDV. No risk factors for GDV were found to correlate between the panda and those described in domestic dogs. This case suggests that red pandas can be susceptible to this condition in captive settings.

Jejuno-jejunal intussusception in a guinea pig (Cavia porcellus)

PubMed Central

Fetzer, Tara J.; Mans, Christoph

2017-01-01

An approximately four-year-old male castrated guinea pig (Cavia porcellus) was presented for painful defecation with a 24-hour history of hyporexia and intermittent episodes of rolling behavior. Upon presentation the patient was quiet, alert, and responsive, and mildly hypothermic. Abdominal palpation revealed an approximately 2-cm long oblong mass within the caudal abdomen. Abdominal radiographs revealed gastric dilation without volvulus and a peritoneal mass effect. The patient was euthanized following gastric reflux of brown malodorous fluid from his nares and oral cavity. A necropsy was performed and revealed a jejuno-jejunal intussusception causing mechanical gastrointestinal ileus, and gastric dilatation without volvulus. While non-obstructive gastrointestinal stasis is common and obstructive ileus is uncommon in guinea pigs, this report shows that intestinal intussusception is a differential in guinea pigs with ileus and gastric dilatation. PMID:29038782

Neonatal Intrathoracic Stomach without Gastric Volvulus.

PubMed

Bokka, Sriharsha; Mohanty, Manoj Kumar

2016-10-01

Intrathoracic stomach is a rare and serious congenital abnormality. The anomaly may be complicated by gastric volvulus and can lead to ischemic gastric infarction in the neonate. If diagnosed antenatally, neonatal management can be planned in advance so as to reduce morbidity. This anomaly must be differentiated from the more common congenital diaphragmatic hernia, as associated pulmonary hypoplasia is common in the latter and rare with gastric herniation. We report a case of intrathoracic stomach in a neonate without volvulus, fortunately a rare entity which was managed operatively, and the child has been under regular follow-up.

Recurrence of gastric dilatation-volvulus after incisional gastropexy in a rottweiler.

PubMed

Hammel, Scott P; Novo, Roberto E

2006-01-01

An adult, castrated male rottweiler with a history of gastric dilatation-volvulus (GDV), which was treated 4 months previously by surgical gastric resection and incisional gastropexy, had a recurrence of clinical signs. Abdominal exploratory surgery revealed a 180 degrees -clockwise GDV, with a stretched adhesion at the original gastropexy site. The stomach was repositioned, and additional gastropexies were performed adjacent to the original gastropexy site and at the gastric fundus. The recurrence of GDV in this dog with an intact gastropexy suggested that a risk for volvulus remains after therapeutic incisional gastropexy.

Sonographic diagnosis of fetal intestinal volvulus with ileal atresia: a case report.

PubMed

Yu, Wang; Ailu, Cai; Bing, Wang

2013-05-01

Fetal intestinal volvulus is a rare life-threatening condition usually manifesting after birth with most cases being associated with intestinal malrotation. It appears on prenatal sonography (US) as a twisting of the bowel loops around the mesenteric artery, leading to mechanical obstruction and ischemic necrosis of the bowel. We report a case of intrauterine intestinal volvulus with ileal atresia, suspected when US revealed a typical "whirlpool" sign at 37 weeks' gestation, with a segment of markedly distended bowel loops and small amount of fetal ascites. Copyright © 2012 Wiley Periodicals, Inc.

Rare small intestinal volvulus from entrapment in hepato-diaphragmatic adhesions in a 45-year-old lady.

PubMed

Olaoye, Iyiade Olatunde; Adesina, Micheal Dapo

2016-12-20

Small intestinal volvulus is rare in adults and rarely caused by string adhesions between the liver and the diaphragm. Similar adhesions were described in Fitz-Hugh-Curtis syndrome. We report a 45-year-old lady with small intestinal volvulus from entrapment of a loop in string adhesions between the liver and the diaphragm. Her plain radiographs showed a significant shadow of the trapped loop. Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author 2016.

Colonic volvulus in the United States: trends, outcomes, and predictors of mortality.

PubMed

Halabi, Wissam J; Jafari, Mehraneh D; Kang, Celeste Y; Nguyen, Vinh Q; Carmichael, Joseph C; Mills, Steven; Pigazzi, Alessio; Stamos, Michael J

2014-02-01

Colonic volvulus is a rare entity associated with high mortality rates. Most studies come from areas of high endemicity and are limited by small numbers. No studies have investigated trends, outcomes, and predictors of mortality at the national level. The Nationwide Inpatient Sample 2002-2010 was retrospectively reviewed for colonic volvulus cases admitted emergently. Patients' demographics, hospital factors, and outcomes of the different procedures were analyzed. The LASSO algorithm for logistic regression was used to build a predictive model for mortality in cases of sigmoid (SV) and cecal volvulus (CV) taking into account preoperative and operative variables. An estimated 3,351,152 cases of bowel obstruction were admitted in the United States over the study period. Colonic volvulus was found to be the cause in 63,749 cases (1.90%). The incidence of CV increased by 5.53% per year whereas the incidence of SV remained stable. SV was more common in elderly males (aged 70 years), African Americans, and patients with diabetes and neuropsychiatric disorders. In contrast, CV was more common in younger females. Nonsurgical decompression alone was used in 17% of cases. Among cases managed surgically, resective procedures were performed in 89% of cases, whereas operative detorsion with or without fixation procedures remained uncommon. Mortality rates were 9.44% for SV, 6.64% for CV, 17% for synchronous CV and SV, and 18% for transverse colon volvulus. The LASSO algorithm identified bowel gangrene and peritonitis, coagulopathy, age, the use of stoma, and chronic kidney disease as strong predictors of mortality. Colonic volvulus is a rare cause of bowel obstruction in the United States and is associated with high mortality rates. CV and SV affect different populations and the incidence of CV is on the rise. The presence of bowel gangrene and coagulopathy strongly predicts mortality, suggesting that prompt diagnosis and management are essential.

Modified tube gastropexy using a mushroom-tipped silicone catheter for management of gastric dilatation-volvulus in dogs.

PubMed

Belch, A; Rubinos, C; Barnes, D C; Nelissen, P

2017-02-01

To report the short- and long-term complications and clinical outcomes of a cohort of dogs managed for gastric dilatation-volvulus using a modified right-sided tube gastropexy technique. Retrospective case series. Of 31 dogs treated, 29 (93·5%) had an excellent short-term outcome, and gastric dilatation-volvulus did not recur in any dog. Twenty-six dogs (84%) were initially fed via the gastrostomy tube postoperatively; three (9·7%) suffered a major complication including septic peritonitis (n=1), and premature tube removal (n=2). Fourteen dogs (45·1%) had minor complications including mild, self-limiting discharge from the stoma site in 13. Modified tube gastropexy using a mushroom-tipped silicone catheter is an effective and safe surgical method for the management of gastric dilatation-volvulus. The gastrostomy tube allowed early enteral feeding and easy administration of medications, including gastroprotectants. © 2017 British Small Animal Veterinary Association.

Intestinal volvulus following laparoscopic surgery: a literature review and case report.

PubMed

Ferguson, Louise; Higgs, Zoe; Brown, Sylvia; McCarter, Douglas; McKay, Colin

2008-06-01

Since its introduction in the early 1990s, the laparoscopic cholecystectomy has become the standard surgical intervention for cholelithiasis. The laparoscopic technique is being used in an increasing number of abdominal procedures. Intestinal volvulus is a rare complication of laparoscopic procedures, such as the laparoscopic cholecystectomy. A review of the literature revealed 12 reports of this complication occurring without a clear cause. Etiologic factors that have been postulated include congenital malrotation, previous surgery, and intraoperative factors, such as pneumoperitoneum, mobilization of the bowel, and patient position. In this paper, we review the literature for this rare complication and report on a case of cecal bascule (a type of cecal volvulus) occurring following the laparoscopic cholecystectomy. Of the 12 prior reports of intestinal volvulus following laparoscopic procedures, 8 of these followed the laparoscopic cholecystectomy, of which two were cecal volvulae. This is the first reported case of a cecal bascule occurring following the laparoscopic cholecystectomy.

An unexpected cause of small bowel obstruction in an adult patient: midgut volvulus

PubMed Central

Söker, Gökhan; Yılmaz, Cengiz; Karateke, Faruk; Gülek, Bozkurt

2014-01-01

The most important complication of intestinal malrotation is midgut volvulus because it may lead to intestinal ischaemia and necrosis. A 29-year-old male patient was admitted to the emergency department with abdominal pain. Ultrasonography (US), colour Doppler ultrasonography (CDUS), CT and barium studies were carried out. On US and CDUS, twisting of intestinal segments around the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) and alteration of the SMA–SMV relationship were detected. CT demonstrated that the small intestine was making a rotation around the SMA and SMV, which amounted to more than 360°. The upper gastrointestinal barium series revealed a corkscrew appearance of the duodenum and proximal jejunum, which is a pathognomonic finding of midgut volvulus. Prior knowledge of characteristic imaging findings of midgut volvulus is essential in order to reach proper diagnosis and establish proper treatment before the development of intestinal ischaemia and necrosis. PMID:24811563

Thoracoscopic management of volvulus of the gastric conduit following minimally invasive Ivor-Lewis esophagectomy.

PubMed

Linson, Jeremy; Latzko, Michael; Ahmed, Bestoun; Awad, Ziad

2016-07-01

We present a case of emergent thoracoscopic management of volvulus of the gastric conduit following minimally invasive Ivor-Lewis esophagectomy. The patient is a 69-year-old Caucasian male with a history of adenocarcinoma of the lower third of the esophagus. Initial presentation was dysphagia with solid foods, which progressed in severity until he was unable to swallow anything. EUS demonstrated a partially obstructing mass at 33 cm; biopsy revealed poorly differentiated adenocarcinoma, stage T3N2Mx. PET scan did not reveal any metastatic disease. Preoperative management included neo-adjuvant chemoradiation therapy (5-FU and cisplatin) and early placement of a jejunal feeding tube. Intra-operative leak test was performed as a matter of routine following completion of the esophagogastric anastomosis. A nasogastric tube was placed intra-operatively and removed on POD2 according to our standard pathway. Postoperatively, the patient progressed without difficulty to POD4, when we routinely obtain an upper GI swallow study. This demonstrated a lack of transit of contrast through the distal neo-esophagus. Follow-up endoscopy revealed volvulus of the gastric conduit with obliteration of the lumen. We immediately took the patient to the OR for thoracoscopic detorsion, which we accomplished successfully by entering the existing trochar sites and using blunt dissection.␣Upon entering the thoracic cavity, the staple line that had been oriented anteriorly was now posterior. Attachments were gently teased away from the chest wall and the conduit was detorsed and anchored to the chest wall in the correct orientation with silk suture. Intra-operative endoscopy demonstrated a patent conduit. Postoperative upper GI fluoroscopy now showed good transit of contrast. The patient continued to improve and was eventually advanced to mechanical soft diet and discharged on postoperative day 9. Early intervention is indicated in cases of volvulus of the gastric conduit following Ivor-Lewis esophagectomy.

Identification of the forest strain of Onchocerca volvulus using the polymerase chain reaction technique.

PubMed

Adewale, B; Mafe, M A; Oyerinde, J P O

2005-01-01

Annual mass treatment with ivermectin for 12-15 years in endemic communities is the control strategy adopted by the African Programme for Onchocerciasis Control (APOC) for the control of onchocerciasis in Nigeria. This long-term treatment necessitates the use of Polymerase Chain Reaction (PCR) for the proper identification of the Onchocerca species and strains in endemic areas and also for monitoring recrudescence of infection in areas where infection has been controlled. This study, which forms part of a larger study on transmission of onchocerciasis identifies the Onchocerca volvulus strain in Ondo state using the Polymerase Chain Reaction (PCR) technique. Deoxyribonucleic acid (DNA) was extracted from the adult worm of Onchocerca parasite using the glass bead method of extraction. The repeated sequence family present in the genome of the parasite designated as 0-150bp was amplified by the polymerase chain reaction (PCR). The amplified parasites produced significant products visible as bands in a 2% agarose gel stained with ethidium bromide. Hybridization of the PCR products with specific DNA probe identified the products as forest strain of Onchocerca volvulus. The epidemiological implication of this is that there would be more of the skin lesions and low blindness rate in the area.

Multidetector computed tomography diagnosis of gastric volvulus through the foramen of Morgagni.

PubMed

Lecouvet, S; Coulier, B; Pierard, F; Gogoase, M; Coppens, J P; Van Hoof, M

2014-01-01

Morgagni hernia is considered to be the rarest form of all diaphragmatic hernias. It develops through a congenital defect in the retrosternal area. Usually asymptomatic, this entity can lead to life-threatening complications such as incarceration, strangulation or volvulus of the herniated viscus. We hereby report a rare case of organoaxial gastric volvulus producing through the foramen of Morgagni in a 78-year-old woman. The full diagnosis was made by upper gastro-intestinal series and multidetector computed tomography (MDCT). The basic anatomy, physiopathology, diagnostic methods, complications and surgical treatment of Morgagni hernia are briefly reviewed.

Gastric dilatation-volvulus after splenic torsion in two dogs.

PubMed

Millis, D L; Nemzek, J; Riggs, C; Walshaw, R

1995-08-01

Two dogs developed gastric dilatation-volvulus 2 and 17 months, respectively, after splenectomy for treatment of splenic torsion. Splenic displacement and torsion may stretch the gastric ligaments, allowing increased mobility of the stomach. After splenectomy, an anatomic void may be created in the cranioventral part of the abdomen, contributing to the mobility of the stomach. Veterinarians treating dogs with isolated splenic torsion may wish to consider prophylactic gastropexy at splenectomy, to reduce the chance of future gastric dilatation-volvulus. Prophylactic gastropexy should be done only if the dog's hemodynamic status is stable enough to allow for performance of the additional surgery.

Cardiac compression due to gastric volvulus: an unusual cause of chest pain.

PubMed

Brown, Alex; Austin, David; Kanakala, Venkatesh

2017-05-22

A 42-year-old man was admitted to coronary care for assessment with severe retrosternal chest pain. Echocardiography showed significant external compression of the left atrium. A subsequent CT scan revealed him to have a large hiatus hernia, with most of his stomach herniating into his thorax causing left atrial compression and gastric volvulus. He subsequently underwent successful emergency decompression of the gastric volvulus and repair of his hiatus hernia. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

The mitogenome of Onchocerca volvulus from the Brazilian Amazonia focus.

PubMed

Crainey, James L; Silva, Túllio R R da; Encinas, Fernando; Marín, Michel A; Vicente, Ana Carolina P; Luz, Sérgio L B

2016-01-01

We report here the first complete mitochondria genome of Onchocerca volvulus from a focus outside of Africa. An O. volvulus mitogenome from the Brazilian Amazonia focus was obtained using a combination of high-throughput and Sanger sequencing technologies. Comparisons made between this mitochondrial genome and publicly available mitochondrial sequences identified 46 variant nucleotide positions and suggested that our Brazilian mitogenome is more closely related to Cameroon-origin mitochondria than West African-origin mitochondria. As well as providing insights into the origins of Latin American onchocerciasis, the Brazilian Amazonia focus mitogenome may also have value as an epidemiological resource.

The risk of midgut volvulus in patients with abdominal wall defects: A multi-institutional study.

PubMed

Fawley, Jason A; Abdelhafeez, Abdelhafeez H; Schultz, Jessica A; Ertl, Allison; Cassidy, Laura D; Peter, Shawn St; Wagner, Amy J

2017-01-01

The management of malrotation in patients with congenital abdominal wall defects has varied among surgeons. We were interested in investigating the risk of midgut volvulus in patients with gastroschisis and omphalocele to help determine if these patients may benefit from undergoing a Ladd procedure. A retrospective chart review was performed for all patients managed at three institutions born between 1/1/2000 and 12/31/2008 with a diagnosis of gastroschisis or omphalocele. Patient charts were reviewed through 12/31/2012 for occurrence of midgut volvulus or need for second laparotomy. Of the 414 patients identified with abdominal wall defects, 299 patients (72%) had gastroschisis, and 115 patients (28%) had omphalocele. The mean gestational age at birth was 36.1±2.3weeks, and the mean birth weight was 2.57±0.7kg. There were a total of 8 (1.9%) cases of midgut volvulus: 3 (1.0%) patients with gastroschisis compared to 5 patients (4.4%) with omphalocele (p=0.04). Patients with omphalocele have a greater risk of developing midgut volvulus, and a Ladd procedure should be considered during definitive repair to mitigate these risks. III; retrospective comparative study. Copyright © 2017 Elsevier Inc. All rights reserved.

Nodding syndrome (NS) and Onchocerca Volvulus (OV) in Northern Uganda.

PubMed

Lagoro, David Kitara; Arony, Denis Anywar

2017-01-01

Nodding Syndrome (NS) is a childhood neurological disorder characterized by atonic seizures, cognitive decline, school dropout, muscle weakness, thermal dysfunction, wasting and stunted growth. There are recent published information suggesting associations between Nodding Syndrome (NS) with cerebrospinal fluid (CSF) VGKC antibodies and serum leiomidin-1 antibody cross reacting with Onchocerca Volvulus ( OV ). These findings suggest a neuro-inflammatory cause of NS and they are important findings in the search for the cause of Nodding Syndrome. These observations perhaps provide further, the unique explanation for the association between Nodding Syndrome and Onchocerca Volvulus . Many clinical and epidemiological studies had shown a significant correlation between NS and infestation with a nematode, Onchocerca volvulus which causes a disease, Onchocerciasis , some of which when left untreated can develop visual defect ("River Blindness"). While these studies conducted in Northern Uganda and Southern Sudan indicate a statistically significant association with ( OV infection (using positive skin snips), we observe that ( OV is generally endemic in many parts of Sub Saharan Africa and Latin America and that to date, no NS cases have been recorded in those regions. This letter to the Editor is to provide additional information on the current view about the relationship between Nodding Syndrome and Onchocerca Volvulus as seen in Northern Uganda.

Nodding syndrome (NS) and Onchocerca Volvulus (OV) in Northern Uganda

PubMed Central

Lagoro, David Kitara; Arony, Denis Anywar

2017-01-01

Nodding Syndrome (NS) is a childhood neurological disorder characterized by atonic seizures, cognitive decline, school dropout, muscle weakness, thermal dysfunction, wasting and stunted growth. There are recent published information suggesting associations between Nodding Syndrome (NS) with cerebrospinal fluid (CSF) VGKC antibodies and serum leiomidin-1 antibody cross reacting with Onchocerca Volvulus (OV). These findings suggest a neuro-inflammatory cause of NS and they are important findings in the search for the cause of Nodding Syndrome. These observations perhaps provide further, the unique explanation for the association between Nodding Syndrome and Onchocerca Volvulus. Many clinical and epidemiological studies had shown a significant correlation between NS and infestation with a nematode, Onchocerca volvulus which causes a disease, Onchocerciasis, some of which when left untreated can develop visual defect ("River Blindness"). While these studies conducted in Northern Uganda and Southern Sudan indicate a statistically significant association with (OV infection (using positive skin snips), we observe that (OV is generally endemic in many parts of Sub Saharan Africa and Latin America and that to date, no NS cases have been recorded in those regions. This letter to the Editor is to provide additional information on the current view about the relationship between Nodding Syndrome and Onchocerca Volvulus as seen in Northern Uganda. PMID:29138647

Design of an adjustable bipod flexure for a large-aperture mirror of a space camera.

PubMed

Liu, Bei; Wang, Wei; Qu, Yan-Jun; Li, Xu-Peng; Wang, Xiao; Zhao, Hui

2018-05-20

An adjustable bipod flexure (ABF) technique for a large-aperture mirror of a space camera is presented. The proposed flexure mount can decrease the surface distortions caused by the machining error and the assembly error of the mirror assembly (MA) in a horizontal optical testing layout. Through the analysis of the compliance matrix of conventional bipod flexure, the positional relationship between the rotation center and the apex of the flexure is investigated. Then, the principle of the adjustable flexure, known as the trapezoidal switching principle, is proposed based on the analysis result. The structure and application of the flexure are also described. The optical performance of the mirror mounted by the adjustable flexures in different misalignments was performed using finite element methods. The result shows that the astigmatic aberration due to gravity is effectively reduced by adjusting the mount, and the root-mean-square value of the mirror can be minimized with the misalignment between the flexure pivot and the neutral plane minimized. New monolithic bipod flexures, based on the optimal regulating variable Δ u according to the measurement results, are manufactured to replace the ABFs to secure the mirror's safety against launch loads. Modal analysis verified the mechanical safety of the MA with respect to the new monolithic flexures.

A rare case of post-splenectomy gastric volvulus managed by laparoscopic anterior gastropexy

PubMed Central

Gupta, Rahul Amreesh; Das, Rinki; Verma, Ganga Ram

2017-01-01

We report an extremely rare case of recurrent gastric volvulus after open splenectomy for hereditary spherocytosis. The initial episode was managed by endoscopic derotation. Later, for recurrent symptoms, she was successfully managed by laparoscopic anterior gastropexy. PMID:28281486

Ongoing Transmission of Onchocerca volvulus after 25 Years of Annual Ivermectin Mass Treatments in the Vina du Nord River Valley, in North Cameroon

PubMed Central

Eisenbarth, Albert; Achukwi, Mbunkah Daniel; Renz, Alfons

2016-01-01

Background Recent reports of transmission interruption of Onchocerca volvulus, the causing agent of river blindness, in former endemic foci in the Americas, and more recently in West and East Africa, raise the question whether elimination of this debilitating disease is underway after long-term treatment of the population at risk with ivermectin. The situation in Central Africa has not yet been clearly assessed. Methods and findings Entomologic data from two former endemic river basins in North Cameroon were generated over a period of 43 and 48 months to follow-up transmission levels in areas under prolonged ivermectin control. Moreover, epidemiologic parameters of animal-borne Onchocerca spp. transmitted by the same local black fly vectors of the Simulium damnosum complex were recorded and their impact on O. volvulus transmission success evaluated. With mitochondrial DNA markers we unambiguously confirmed the presence of infective O. volvulus larvae in vectors from the Sudan savannah region (mean Annual Transmission Potential 2009–2012: 98, range 47–221), but not from the Adamawa highland region. Transmission rates of O. ochengi, a parasite of Zebu cattle, were high in both foci. Conclusions/significance The high cattle livestock density in conjunction with the high transmission rates of the bovine filaria O. ochengi prevents the transmission of O. volvulus on the Adamawa plateau, whereas transmission in a former hyperendemic focus was markedly reduced, but not completely interrupted after 25 years of ivermectin control. This study may be helpful to gauge the impact of the presence of animal-filariae for O. volvulus transmission in terms of the growing human and livestock populations in sub-Saharan countries. PMID:26926855

Primary Volvulus of the Small Intestine Exhibiting Chylous Ascites: A Case Report.

PubMed

Hayama, Tamuro; Shioya, Takeshi; Hankyo, Meishi; Shimizu, Takao; Shibuya, Hajime; Komine, Osamu; Watanabe, Yoshimasa; Nanbu, Kotaro; Yamada, Taro

2017-01-01

Primary volvulus of the small intestine associated with chylous ascites is very rare, with only four reported cases. In this paper, we report a new case of primary volvulus associated with chylous ascites. The patient was a 70-year-old man. After experiencing bloating and abdominal pain for several hours, he called an ambulance and underwent an emergency examination at our hospital. Abdominal distension, pressure pain, and rebound tenderness were observed throughout his entire abdomen. The patient had a history of hypertension for which he was receiving oral treatment. Abdominal contrast-enhanced computed tomography (CT) revealed an edematous change in the intestinal membrane and volvulus of the small intestine. As findings suggestive of ischemia were observed in part of the intestines, emergency surgery was performed on the day of admission. Open surgery revealed approximately 500 mL of chylous ascites in the abdominal cavity. The small intestine had twisted 180° in a counter-clockwise direction at the root of the superior mesenteric artery, and the mesentery appeared milky white with edematous changes extending 75 to 240 cm from the ligament of Treitz. There was no evidence of intestinal necrosis; therefore intestinal resection was not performed. The volvulus of the small intestine was corrected. Moreover, because there was no other underlying disease observed, surgery was completed. The ascites collected during surgery revealed high levels of triglycerides at 332 mg/dL, and chylous ascites was diagnosed. An abdominal CT performed on the third day after surgery showed an improvement in intestinal edema, and primary volvulus of the small intestine associated with chylous ascites was diagnosed. Postoperative progress was good, and the patient was discharged on hospital day 10.

Intestinal Malrotation and Volvulus in Neonates: Laparoscopy Versus Open Laparotomy.

PubMed

Ferrero, Luisa; Ahmed, Yosra Ben; Philippe, Paul; Reinberg, Olivier; Lacreuse, Isabelle; Schneider, Anne; Moog, Raphael; Gomes-Ferreira, Cindy; Becmeur, François

2017-03-01

Intestinal malrotations with midgut volvulus are surgical emergencies that can lead to life-threatening intestinal necrosis. This study evaluates the feasibility and the outcomes of laparoscopic treatment of midgut volvulus compared with classic open Ladd's procedure in neonates. The medical records of all neonates with diagnosis of malrotation and volvulus, who underwent surgery between January 1993 and January 2014, were reviewed. We considered the group of neonates laparoscopically treated (Group A, n = 20) and we compared it with an equal number of neonates treated with the classical open Ladd's procedure (Group B, n = 20). The median age at surgery was 8.4 days and the mean weight was 3.340 kg. The suspicion of volvulus was documented by plain abdominal radiograph, upper gastrointestinal contrast study, and/or ultrasound scanning of the mesenteric vessels. All the patients were treated according to the Ladd's procedure. Conversion to an open procedure was necessary in 25% of the patients. The mean operative time was 80 minutes (28-190 minutes) in Group A and 61 minutes (40-130 minutes) in Group B (P = .04). The median time to full diet (P = .02) and hospital stay (P = .04) was better in Group A. Rehospitalization because of recurrence of occlusive symptoms occurred in 30% of patients in Group A (n = 6) and in 40% of patients in Group B (n = 8). Among these, all the 6 patients of Group A underwent redo surgery for additional division of Ladd's bands or debridement; instead in Group B, 4 of 8 patients underwent open redo surgery. Laparoscopic exploration is the procedure of choice in case of suspicion of intestinal malrotation and volvulus. Laparoscopic treatment is feasible and safe even in neonatal age without additional risks compared with classical open Ladd's procedure.

Successful Interruption of Transmission of Onchocerca volvulus in the Escuintla-Guatemala Focus, Guatemala

PubMed Central

Gonzalez, Rodrigo J.; Cruz-Ortiz, Nancy; Rizzo, Nidia; Richards, Jane; Zea-Flores, Guillermo; Domínguez, Alfredo; Sauerbrey, Mauricio; Catú, Eduardo; Oliva, Orlando; Richards, Frank O.; Lindblade, Kim A.

2009-01-01

Background Elimination of onchocerciasis (river blindness) through mass administration of ivermectin in the six countries in Latin America where it is endemic is considered feasible due to the relatively small size and geographic isolation of endemic foci. We evaluated whether transmission of onchocerciasis has been interrupted in the endemic focus of Escuintla-Guatemala in Guatemala, based on World Health Organization criteria for the certification of elimination of onchocerciasis. Methodology/Principal Findings We conducted evaluations of ocular morbidity and past exposure to Onchocerca volvulus in the human population, while potential vectors (Simulium ochraceum) were captured and tested for O. volvulus DNA; all of the evaluations were carried out in potentially endemic communities (PEC; those with a history of actual or suspected transmission or those currently under semiannual mass treatment with ivermectin) within the focus. The prevalence of microfilariae in the anterior segment of the eye in 329 individuals (≥7 years old, resident in the PEC for at least 5 years) was 0% (one-sided 95% confidence interval [CI] 0–0.9%). The prevalence of antibodies to a recombinant O. volvulus antigen (Ov-16) in 6,432 school children (aged 6 to 12 years old) was 0% (one-sided 95% IC 0–0.05%). Out of a total of 14,099 S. ochraceum tested for O. volvulus DNA, none was positive (95% CI 0–0.01%). The seasonal transmission potential was, therefore, 0 infective stage larvae per person per season. Conclusions/Significance Based on these evaluations, transmission of onchocerciasis in the Escuintla-Guatemala focus has been successfully interrupted. Although this is the second onchocerciasis focus in Latin America to have demonstrated interruption of transmission, it is the first focus with a well-documented history of intense transmission to have eliminated O. volvulus. PMID:19333366

A Clinician's Guide to the Diagnosis and Management of Gallbladder Volvulus.

PubMed

Pottorf, Brian J; Alfaro, Leonardo; Hollis, Harris W

2013-01-01

Gallbladder volvulus (GV), or torsion of the gallbladder, is an uncommon surgical emergency. This article reviews the world literature related to GV. We examine the history of gallbladder torsion and highlight the critical constellation of presenting signs and symptoms, which guide the acute care physician and surgeon to accurate and timely diagnosis of GV before surgical intervention. A comprehensive review of all published cases of GV was performed using the National Library of Medicine (PubMed) database. Lists of typical symptoms and clinical presentations are provided to allow clinicians to establish an accurate preoperative diagnosis. GV is frequently undiagnosed before surgical intervention. However, clinical presentation and associated radiographic findings can lead to an accurate diagnosis if the clinician is aware of this uncommon condition. When the diagnosis has been established before operative intervention, expeditious laparoscopic cholecystectomy can be performed safely. Delays in diagnosis may mandate open cholecystectomy if laparoscopic extraction is contraindicated because of undesirable sequelae of gallbladder necrosis, specifically perforation, bilious peritonitis, and hemodynamic instability.

Late intestinal obstruction due to an intestinal volvulus in a pregnant patient with a previous Roux-en-Y gastric bypass.

PubMed

Gazzalle, Anajara; Braun, Débora; Cavazzola, Leandro Totti; Wendt, Luiz Roberto; Navarini, Daniel; Fauri, Marcelo de Azevedo; Vitola, Santo Pascual

2010-12-01

This is a case of a 33 weeks pregnant woman, presented 2 years after laparoscopic Roux-en-Y gastric bypass, with abdominal pain for 2 days. A laparoscopic cholecystectomy was performed 1 day earlier in another hospital, without improving the pain. She presented at our hospital with acute abdominal pain and clinical signs of intestinal obstruction, undergoing an exploratory laparotomy that revealed a volvulus and necrosis of the jejunum from the gastroenteroanastomosis through the lateral enteroenterostomy, which was resected with the reconstruction of the Roux-en-Y limb performed at the same operation. Patient and neonate presented with improvement after surgery and the patient was discharged on postoperative day 15. Internal hernias after bariatric surgery have been reported as the cause of acute abdomen problems during pregnancy, which may progress to necrosis and perforation. The delay of surgical intervention could have brought a tragic outcome for mother and neonate.

Cross-sectional study of the association of abomasal displacement or volvulus with serum electrolyte and mineral concentrations in dairy cows.

PubMed Central

Delgado-Lecaroz, R; Warnick, L D; Guard, C L; Smith, M C; Barry, D A

2000-01-01

The objective of this study was to evaluate serum mineral and electrolyte concentrations at the time of on-farm diagnosis of left displaced abomasum, right displaced abomasum, or abomasal volvulus in dairy cows. Data were collected from 104 affected cows and 96 control cows matched with cases, based on herd, parity, and stage of lactation. Cows with abomasal displacement or volvulus had significantly lower calcium, phosphorous, magnesium, potassium, and chloride concentrations and increased anion gap at the time of diagnosis compared with control cows from the same herds. The percentages of cases and controls with total serum calcium concentrations below the lower limit of the laboratory reference range (2.08 mmol/L [8.3 mg/dL]) were 70% and 23%, respectively. Based on the large percentage of cases with hypocalcemia, administering calcium salts at the time of treatment of field cases of abomasal displacement or volvulus may be beneficial. PMID:10769767

Prospective analysis of percutaneous endoscopic colostomy at a tertiary referral centre.

PubMed

Baraza, W; Brown, S; McAlindon, M; Hurlstone, P

2007-11-01

Percutaneous endoscopic colostomy (PEC) is an alternative to surgery in selected patients with recurrent sigmoid volvulus, recurrent pseudo-obstruction or severe slow-transit constipation. A percutaneous tube acts as an irrigation or decompressant channel, or as a mode of sigmoidopexy. This prospective study evaluated the safety and efficacy of this procedure at a single tertiary referral centre. Nineteen patients with recurrent sigmoid volvulus, ten with idiopathic slow-transit constipation and four with pseudo-obstruction underwent PEC. The tube was left in place indefinitely in those with recurrent sigmoid volvulus or constipation, whereas in patients with pseudo-obstruction it was left in place for a variable period of time, depending on symptoms. Thirty-five procedures were performed in 33 patients. Three patients developed peritonitis, of whom one died, and ten patients had minor complications. Symptoms resolved in 26 patients. This large prospective study has confirmed the value of PEC in the treatment of recurrent sigmoid volvulus and pseudo-obstruction in high-risk surgical patients. Copyright (c) 2007 British Journal of Surgery Society Ltd.

Intestinal volvulus in cetaceans.

PubMed

Begeman, L; St Leger, J A; Blyde, D J; Jauniaux, T P; Lair, S; Lovewell, G; Raverty, S; Seibel, H; Siebert, U; Staggs, S L; Martelli, P; Keesler, R I

2013-07-01

Intestinal volvulus was recognized as the cause of death in 18 cetaceans, including 8 species of toothed whales (suborder Odontoceti). Cases originated from 11 institutions from around the world and included both captive (n = 9) and free-ranging (n = 9) animals. When the clinical history was available (n = 9), animals consistently demonstrated acute dullness 1 to 5 days prior to death. In 3 of these animals (33%), there was a history of chronic gastrointestinal illness. The pathological findings were similar to those described in other animal species and humans, and consisted of intestinal volvulus and a well-demarcated segment of distended, congested, and edematous intestine with gas and bloody fluid contents. Associated lesions included congested and edematous mesentery and mesenteric lymph nodes, and often serofibrinous or hemorrhagic abdominal effusion. The volvulus involved the cranial part of the intestines in 85% (11 of 13). Potential predisposing causes were recognized in most cases (13 of 18, 72%) but were variable. Further studies investigating predisposing factors are necessary to help prevent occurrence and enhance early clinical diagnosis and management of the condition.

The genome of Onchocerca volvulus, agent of river blindness

PubMed Central

Cotton, James A.; Bennuru, Sasisekhar; Grote, Alexandra; Harsha, Bhavana; Tracey, Alan; Beech, Robin; Doyle, Stephen R.; Dunn, Matthew; Dunning Hotopp, Julie C.; Holroyd, Nancy; Kikuchi, Taisei; Lambert, Olivia; Mhashilkar, Amruta; Mutowo, Prudence; Nursimulu, Nirvana; Ribeiro, Jose M. C.; Rogers, Matthew B.; Stanley, Eleanor; Swapna, Lakshmipuram S.; Tsai, Isheng J.; Unnasch, Thomas R.; Voronin, Denis; Parkinson, John; Nutman, Thomas B.; Ghedin, Elodie; Berriman, Matthew; Lustigman, Sara

2017-01-01

Human onchocerciasis is a serious neglected tropical disease caused by the filarial nematode Onchocerca volvulus that can lead to blindness and chronic disability. Control of the disease relies largely on mass administration of a single drug, and the development of new drugs and vaccines depends on a better knowledge of parasite biology. Here, we describe the chromosomes of O. volvulus and its Wolbachia endosymbiont. We provide the highest-quality sequence assembly for any parasitic nematode to date, giving a glimpse into the evolution of filarial parasite chromosomes and proteomes. This resource was used to investigate gene families with key functions that could be potentially exploited as targets for future drugs. Using metabolic reconstruction of the nematode and its endosymbiont, we identified enzymes that are likely to be essential for O. volvulus viability. In addition, we have generated a list of proteins that could be targeted by Federal-Drug-Agency-approved but repurposed drugs, providing starting points for anti-onchocerciasis drug development. PMID:27869790

Gastric dilation-volvulus in dogs attending UK emergency-care veterinary practices: prevalence, risk factors and survival.

PubMed

O'Neill, D G; Case, J; Boag, A K; Church, D B; McGreevy, P D; Thomson, P C; Brodbelt, D C

2017-11-01

To report prevalence, risk factors and clinical outcomes for presumptive gastric dilation-volvulus diagnosed among an emergency-care population of UK dogs. The study used a cross-sectional design using emergency-care veterinary clinical records from the VetCompass Programme spanning September 1, 2012 to February 28, 2014 and risk factor analysis using multivariable logistic regression modelling. The study population comprised 77,088 dogs attending 50 Vets Now clinics. Overall, 492 dogs had presumptive gastric dilation-volvulus diagnoses, giving a prevalence of 0·64% (95% Confidence interval: 0·58 to 0·70%). Compared with cross-bred dogs, breeds with the highest odds ratios for the diagnosis of presumptive gastric dilation-volvulus were the great Dane (odds ratio: 114·3, 95% Confidence interval 55·1 to 237·1, P<0·001), akita (odds ratio: 84·4, 95% Confidence interval 33·6 to 211·9, P<0·001) and dogue de Bordeaux (odds ratio: 82·9, 95% Confidence interval 39·0 to 176·3, P<0·001). Odds increased as dogs aged up to 12 years and neutered male dogs had 1·3 (95% Confidence interval 1·0 to 1·8, P=0·041) times the odds compared with entire females. Of the cases that were presented alive, 49·7% survived to discharge overall, but 79·3% of surgical cases survived to discharge. Approximately 80% of surgically managed cases survived to discharge. Certain large breeds were highly predisposed. © 2017 British Small Animal Veterinary Association.

Volvulus of the colon in four dogs.

PubMed

Bentley, Adrienne M; O'Toole, Therese E; Kowaleski, Michael P; Casale, Sue A; McCarthy, Robert J

2005-07-15

Four dogs were examined because of vomiting of 7 to 48 hours' duration. Gas-distended segments of intestine were identified radiographically in all dogs, but the affected portion of the intestinal tract could not always be identified as the colon. Volvulus of the colon was diagnosed during surgery in all 4 dogs. Gastrocolopexy was performed following derotation of the colon in 3 of the dogs. In 1 dog, a colectomy and an ileorectal anastomosis were performed. All 4 dogs survived. Volvulus of the colon should be considered as a cause of vomiting of short duration in dogs for which there is radiographic evidence of intestinal dilatation.

Volvulus of the Small Intestine in Adults

PubMed Central

Talbot, C. H.

1960-01-01

Five cases of volvulus of varying lengths of the small intestine are described. The incidence and the aetiology of the condition are briefly discussed. Shock as a feature of extensive volvulus is stressed, and its cause in these cases is related to the previous animal experimental work of others. The other clinical features are briefly described. In the management of these cases the urgency for laparotomy is stressed and immediate delivery from the abdomen of the whole small bowel is advocated. Reference is made to the literature of massive resection of the small intestine to illustrate that the prognosis is not necessarily poor when resections are extensive. PMID:13836720

Management of sigmoid volvulus: options and prognosis.

PubMed

Maddah, Ghodratollah; Kazemzadeh, Gholam Hossein; Abdollahi, Abbas; Bahar, Mostafa Mehrabi; Tavassoli, Alireza; Shabahang, Hossein

2014-01-01

To describe the management of sigmoid volvulus with reference to the type of surgical procedures performed and to determine the prognosis of sigmoid volvulus. A case series. Ghaem Hospital of Mashhad, University of Medical Sciences, Mashhad, Iran, from 1996 to 2008. A total of 944 cases of colon obstruction were reviewed. Demographic, laboratory and treatment results, mortality and complications were recorded. The data was analyzed using descriptive statistics as frequency and percentage for the qualitative variables and mean and standard deviation values for the quantitative variables. Also chisquare and Fisher's exact test were used for the association between the qualitative variables. SPSS statistical software (version 18) was used for the data analysis. In all patients except those with symptoms or signs of gangrenous bowel, a long rectal tube was inserted via the rectosigmoidoscope which was successful in 80 (36.87%) cases. Rectosigmoidoscopic detorsion was unsuccessful in 137 (63.13%) patients, who underwent an emergent laparotomy. The surgical procedures performed in these cases were resection and primary anastomosis in 40 (29.1%), Mikulicz procedure in 9 (6.6%), laparotomy detorsion in 37 (27.01%), Hartmann procedure in 47 (34.3%), mesosigmoidoplasty in 3 (2.19%) patients and total colectomy in one (0.73%) case. The overall mortality was 9.8% (22) patients. In sigmoid volvulus, the most important determinant of patient outcome is bowel viability. The initial treatment of sigmoid colon volvulus is sigmoidoscopy with rectal tube placement.

Elimination of Onchocerca volvulus Transmission in the Huehuetenango Focus of Guatemala

PubMed Central

Cruz-Ortiz, Nancy; Gonzalez, Rodrigo J.; Lindblade, Kim A.; Richards, Frank O.; Sauerbrey, Mauricio; Zea-Flores, Guillermo; Dominguez, Alfredo; Oliva, Orlando; Catú, Eduardo; Rizzo, Nidia

2012-01-01

In Latin America, onchocerciasis is targeted for elimination by 2012 through twice-yearly mass treatment of the eligible population with ivermectin. In Guatemala, two of the four historical endemic foci have demonstrated elimination of transmission, following World Health Organization guidelines. Using established guidelines ophthalmological, serological, and entomological evaluations were conducted in 2007-8 to determine the transmission status of onchocerciasis in the Huehuetenango focus. The prevalence of Onchocerca volvulus microfilariae in the anterior segment of the eye in 365 residents was 0% (95% confidence interval [CI] 0–0.8%), the prevalence of infection of O. volvulus in Simulium ochraceum among 8252 flies collected between November 2007 and April 2008 was 0% (95% CI 0–0.02%), and the prevalence of antibodies to a recombinant O. volvulus antigen in 3118 school age children was 0% (95% CI 0–0.1%). These results showed transmission interruption; thus, in 2009 mass treatment was halted and posttreatment surveillance began. To verify for potential recrudescence an entomological evaluation (from December 2010 to April 2011) was conducted during the 2nd and 3rd year of posttreatment surveillance. A total of 4587 S. ochraceum were collected, and the prevalence of infection of O. volvulus was 0% (95% CI 0–0.04%). Transmission of onchocerciasis in the Huehuetenango focus has been eliminated. PMID:22970346

Gastric dilatation-volvulus syndrome in dogs.

PubMed

Monnet, Eric

2003-09-01

Gastric dilatation-volvulus is a medical and surgical emergency that principally affects large-breed dogs. Surgical treatment should be undertaken as soon as the patient has been stabilized with fluid therapy and decompression. A gastrectomy might be required if the stomach is becoming necrotic. A gastropexy is required to prevent recurrence.

Rectal volvulus following laparoscopic left hemicolectomy

PubMed Central

Sutton, Paul Anthony; Lee, Han Sian; Din, Islah; Vimalachandran, Dale

2013-01-01

A 60-year-old lady with a history of Dukes B2 (T3N0M0) colorectal cancer presented some 2 years following a laparoscopic left hemicolectomy with a 4-day history of absolute constipation. A plain radiograph demonstrated large bowel obstruction, and subsequent CT of the abdomen showed the level of the obstruction to be at the rectum. Initially the aetiology was believed to be recurrence at the site of the anastomosis; however, subsequent review of the imaging and indeed endoscopic examination of the rectum showed it to be volvulus. This was initially treated with endoscopic decompression and later by the insertion of a flatus tube to good effect. The patient was discharged 3 days later with no recurrence of her symptoms at 2 months. PMID:23608861

Prediction of Mean and Design Fatigue Lives of Self Compacting Concrete Beams in Flexure

NASA Astrophysics Data System (ADS)

Goel, S.; Singh, S. P.; Singh, P.; Kaushik, S. K.

2012-02-01

In this paper, result of an investigation conducted to study the flexural fatigue characteristics of self compacting concrete (SCC) beams in flexure are presented. An experimental programme was planned in which approximately 60 SCC beam specimens of size 100 × 100 × 500 mm were tested under flexural fatigue loading. Approximately 45 static flexural tests were also conducted to facilitate fatigue testing. The flexural fatigue and static flexural strength tests were conducted on a 100 kN servo-controlled actuator. The fatigue life data thus obtained have been used to establish the probability distributions of fatigue life of SCC using two-parameter Weibull distribution. The parameters of the Weibull distribution have been obtained by different methods of analysis. Using the distribution parameters, the mean and design fatigue lives of SCC have been estimated and compared with Normally vibrated concrete (NVC), the data for which have been taken from literature. It has been observed that SCC exhibits higher mean and design fatigue lives compared to NVC.

Meckel's diverticulum incarcerated in a transmesocolic internal hernia

PubMed Central

Wu, Si-Yuan; Ho, Meng-Hsing; Hsu, Sheng-Der

2014-01-01

Intestinal obstruction is a common complication associated with Meckel’s diverticulum in adults. The diverticulum itself or its fibrous band can lead to an intestinal volvulus, intussusceptions, or closed-loop obstructions, which require surgery. The incarceration of Meckel’s diverticulum in either inguinal or femoral hernia sacs (Littre’s hernia) is another, less common, etiology underlying intestinal obstruction. This case report describes a 45-year-old man who had an obstruction associated with a Meckel’s diverticulum that passed through a congenital defect in the mesocolon into the right subphrenic space. The patient, who had not undergone abdominal surgery previously, came to the emergency room with acute onset of intermittent epigastric pain and abdominal distention. Computed tomography images showed the presence of a segment of the small bowel and a diverticulum in the right subphrenic space and paracolic gutter. The twisted mesentery and the dilated loops of the proximal small bowel were indicative of an intestinal volvulus and obstruction. Meckel’s diverticulum complicated by a transmesocolic internal hernia was diagnosed, and this condition was confirmed during emergency surgery. The patient’s postoperative recovery was uneventful. This case report highlights another presentation of Meckel’s diverticulum, that is, in combination with a transmesocolic internal hernia. This etiology may lead to an intestinal volvulus and necessitate early surgery. PMID:25309093

A case of triple volvulus.

PubMed

Elsharif, M; Basu, I; Phillips, D

2012-03-01

Situs inversus is a rare congenital anomaly that has reportedly been associated with caecal volvulus. We describe a case of partial situs inversus complicated by intestinal obstruction secondary to three simultaneously occurring volvuli of the stomach, caecum and sigmoid colon. To our knowledge, this is the first documented case in the literature of multiple, simultaneously occurring volvuli.

Bile peritonitis associated with gastric dilation-volvulus in a dog.

PubMed

Hewitt, Saundra A; Brisson, Brigitte A; Holmberg, David L

2005-03-01

This report describes a case of septic peritonitis and gall bladder rupture in German shepherd dog that developed 7 d after surgical treatment for gastric dilation-volvulus. Histological examination confirmed gall bladder necrosis, secondary to an acute ischemic event. Postoperative acute necrotizing cholecystitis has not been a previously reported complication in dogs.

The efficiency of sonography in diagnosing volvulus in neonates with suspected intestinal malrotation

PubMed Central

Zhang, Wenhua; Sun, Hongjun; Luo, Fangqiong

2017-01-01

Abstract This study is to prospectively evaluate the efficiency of sonography for volvulus diagnosis in neonates with clinically suspected intestinal malrotation. A total of 83 patients with suspected intestinal malrotation who underwent detailed abdominal sonography and upper gastrointestinal contrast study were included. Malrotation was characterized by inversion of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) in sonographic examination. The “whirlpool sign” of Color Doppler Sonography was recognized as a characteristic for malrotation with volvulus. The degrees of rotation of the SMV winding around SMA were also detected by sonography. Surgery was performed in patients with sonography diagnosed malrotation. A total of 39 patients were sonographically diagnosed as malrotation which was subsequently confirmed by surgery. The sensitivity and positive predictive value of the sonographic diagnosis were both 100% (39/39). The sensitivity, specificity and accuracy of “whirlpool sign” for the detection of midgut volvulus were 95.2% (20/21), 88.9% (16/18), and 92.3% (36/39), respectively. Greater degrees of rotation (equal or greater than 720°) showed higher risk (odds ratio, 5.0; P < .01) for intestinal necrosis occurrence. Sonography is more accurate in diagnosing suspected malrotation than upper gastrointestinal contrast study. Specific sonographic “whirlpool sign” related to volvulus may be used as a potential indicator for intestinal necrosis. In addition, sonography can exclude malrotation and may help the diagnosis of other diseases, such as annular pancreas and duodenal atresia. PMID:29049228

The efficiency of sonography in diagnosing volvulus in neonates with suspected intestinal malrotation.

PubMed

Zhang, Wenhua; Sun, Hongjun; Luo, Fangqiong

2017-10-01

This study is to prospectively evaluate the efficiency of sonography for volvulus diagnosis in neonates with clinically suspected intestinal malrotation.A total of 83 patients with suspected intestinal malrotation who underwent detailed abdominal sonography and upper gastrointestinal contrast study were included. Malrotation was characterized by inversion of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) in sonographic examination. The "whirlpool sign" of Color Doppler Sonography was recognized as a characteristic for malrotation with volvulus. The degrees of rotation of the SMV winding around SMA were also detected by sonography. Surgery was performed in patients with sonography diagnosed malrotation.A total of 39 patients were sonographically diagnosed as malrotation which was subsequently confirmed by surgery. The sensitivity and positive predictive value of the sonographic diagnosis were both 100% (39/39). The sensitivity, specificity and accuracy of "whirlpool sign" for the detection of midgut volvulus were 95.2% (20/21), 88.9% (16/18), and 92.3% (36/39), respectively. Greater degrees of rotation (equal or greater than 720°) showed higher risk (odds ratio, 5.0; P < .01) for intestinal necrosis occurrence.Sonography is more accurate in diagnosing suspected malrotation than upper gastrointestinal contrast study. Specific sonographic "whirlpool sign" related to volvulus may be used as a potential indicator for intestinal necrosis. In addition, sonography can exclude malrotation and may help the diagnosis of other diseases, such as annular pancreas and duodenal atresia.

Gallbladder Volvulus: A Rare Emergent Cause of Acute Cholecystitis, if Untreated, Progresses to Necrosis and Perforation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Justin L, Regner, E-mail: Justin.Regner@BSWHealth.org; Angela, Lomas

An 86 year-old woman with a past medical history significant for abdominal hernia and Alzheimer dementia presented to the Emergency Department with a 24 hour history of acute right upper quadrant pain associated with nausea and non-bilious emesis. Physical exam revealed right sided abdominal tenderness with associated mass. All laboratory values were within normal ranges. Both abdominal ultrasound and computed tomography of the abdomen/pelvis revealed a large distended gallbladder with wall thickening and gallstones. Based on presentation and radiologic findings, the emergency general surgery service was consulted for suspected acute cholecystitis. The patient was then admitted for intravenous antibiotics andmore » scheduled for laparoscopic cholecystectomy the following day. Intra-operative findings revealed volvulus with acute necrosis of the entire gallbladder. The gallbladder had a long pedunculated cystic duct and artery that was detorsed before proceeding with resection. Postoperatively, the patient did well and was discharged a few days later tolerating a regular diet.« less

Finite Element Analysis and Optimization of Flexure Bearing for Linear Motor Compressor

NASA Astrophysics Data System (ADS)

Khot, Maruti; Gawali, Bajirao

Nowadays linear motor compressors are commonly used in miniature cryocoolers instead of rotary compressors because rotary compressors apply large radial forces to the piston, which provide no useful work, cause large amount of wear and usually require lubrication. Recent trends favour flexure supported configurations for long life. The present work aims at designing and geometrical optimization of flexure bearings using finite element analysis and the development of design charts for selection purposes. The work also covers the manufacturing of flexures using different materials and the validation of the experimental finite element analysis results.

A Clinician’s Guide to the Diagnosis and Management of Gallbladder Volvulus

PubMed Central

Pottorf, Brian J; Alfaro, Leonardo; Hollis, Harris W

2013-01-01

Introduction: Gallbladder volvulus (GV), or torsion of the gallbladder, is an uncommon surgical emergency. This article reviews the world literature related to GV. We examine the history of gallbladder torsion and highlight the critical constellation of presenting signs and symptoms, which guide the acute care physician and surgeon to accurate and timely diagnosis of GV before surgical intervention. Methods: A comprehensive review of all published cases of GV was performed using the National Library of Medicine (PubMed) database. Results: Lists of typical symptoms and clinical presentations are provided to allow clinicians to establish an accurate preoperative diagnosis. Conclusion: GV is frequently undiagnosed before surgical intervention. However, clinical presentation and associated radiographic findings can lead to an accurate diagnosis if the clinician is aware of this uncommon condition. When the diagnosis has been established before operative intervention, expeditious laparoscopic cholecystectomy can be performed safely. Delays in diagnosis may mandate open cholecystectomy if laparoscopic extraction is contraindicated because of undesirable sequelae of gallbladder necrosis, specifically perforation, bilious peritonitis, and hemodynamic instability. PMID:23704849

A case of triple volvulus

PubMed Central

Basu, I; Phillips, D

2012-01-01

Situs inversus is a rare congenital anomaly that has reportedly been associated with caecal volvulus. We describe a case of partial situs inversus complicated by intestinal obstruction secondary to three simultaneously occurring volvuli of the stomach, caecum and sigmoid colon. To our knowledge, this is the first documented case in the literature of multiple, simultaneously occurring volvuli. PMID:22391352

Bile peritonitis associated with gastric dilation-volvulus in a dog

PubMed Central

2005-01-01

Abstract This report describes a case of septic peritonitis and gall bladder rupture in German shepherd dog that developed 7 d after surgical treatment for gastric dilation-volvulus. Histological examination confirmed gall bladder necrosis, secondary to an acute ischemic event. Postoperative acute necrotizing cholecystitis has not been a previously reported complication in dogs. PMID:15884650

Flexural Behavior of HPFRCC Members with Inhomogeneous Material Properties.

PubMed

Shin, Kyung-Joon; Jang, Kyu-Hyeon; Choi, Young-Cheol; Lee, Seong-Cheol

2015-04-21

In this paper, the flexural behavior of High-performance Fiber-Reinforced Cementitious Composite (HPFRCC) has been investigated, especially focusing on the localization of cracks, which significantly governs the flexural behavior of HPFRCC members. From four points bending tests with HPFRCC members, it was observed that almost evenly distributed cracks formed gradually, followed by a localized crack that determined the failure of the members. In order to investigate the effect of a localized crack on the flexural behavior of HPFRCC members, an analytical procedure has been developed with the consideration of intrinsic inhomogeneous material properties of HPFRCC such as cracking and ultimate tensile strengths. From the comparison, while the predictions with homogeneous material properties overestimated flexural strength and ductility of HPFRCC members, it was found that the analysis results considering localization effect with inhomogeneous material properties showed good agreement with the test results, not only the flexural strength and ductility but also the crack widths. The test results and the developed analysis procedure presented in this paper can be usefully applied for the prediction of flexural behaviors of HPFRCC members by considering the effect of localized cracking behavior.

Emergency canine surgery in a deployed forward surgical team: a case report.

PubMed

Beitler, Alan L; Jeanette, Joseph P; McGraw, Andrew L; Butera, Jennifer R; Vanfosson, Christopher A; Seery, Jason M

2011-04-01

Forward surgical teams (FSTs) perform a variety of non-doctrinal functions. During their deployment to Afghanistan, the 541st FST (Airborne) performed emergency surgery on a German shepherd military working dog (MWD). Retrospective examination of a case of veterinary surgery in a deployed FST. A 5 1/2-year-old German shepherd MWD presented with extreme lethargy, tachycardia, excessive drooling, and a firm, distended abdomen. These conditions resulted from gastric dilatation with volvulus. Since evacuation to a veterinarian was untenable, emergency laparotomy was performed in the FST. The gastric dilatation with volvulus was treated by detorsion and gastropexy, and the canine patient fully recovered. Canine surgery can be safely performed in an FST. Based on the number of MWDs deployed throughout the theater, FSTs may be called upon to care for them in the absence of available veterinary care.

[Intrauterine intestinal volvulus].

PubMed

Gawrych, Elzbieta; Chojnacka, Hanna; Wegrzynowski, Jerzy; Rajewska, Justyna

2009-07-01

Intrauterine intestinal volvulus is an extremely rare case of acute congenital intestinal obstruction. The diagnosis is usually possible in the third trimester of a pregnancy. Fetal midgut volvulus is most likely to be recognized by observing a typical clockwise whirlpool sign during color Doppler investigation. Multiple dilated intestinal loops with fluid levels are usually visible during the antenatal ultrasound as well. Physical and radiographic findings in the newborn indicate intestinal obstruction and an emergency surgery is required. The authors describe intrauterine volvulus in 3 female newborns in which surgical treatment was individualized. The decision about primary or delayed anastomosis after resection of the gangrenous part of the small bowel was made at the time of the surgery and depended on the general condition of the newborn, as well as presence or absence of meconium peritonitis. Double loop jejunostomy was performed in case of two newborns, followed by a delayed end-to-end anastomosis. In case of the third newborn, good blood supply of the small intestine after untwisting and 0.25% lignocaine injections into mesentery led to the assumption that the torsion was not complete and ischemia was reversible. In the two cases of incomplete rotation the cecum was sutured to the left abdominal wall to prevent further twisting. The postoperative course was uneventful and oral alimentation caused no problems. Physical development of all these children has been normal (current age: 1-2 years) and the parents have not observed any disorders or problems regarding passage of food through the alimentary canal. Prompt antenatal diagnosis of this surgical emergency and adequate choice of intervention may greatly reduce mortality due to intrauterine volvulus.

Novel Approach to Treat Uncomplicated Sigmoid Volvulus Combining Minimally Invasive Surgery with Enhanced Recovery, in a Rural Hospital in Zambia.

PubMed

van der Naald, Niels; Prins, Marloes I; Otten, Kars; Kumwenda, Dayson; Bleichrodt, Robert P

2018-06-01

In sub-Saharan Africa, sigmoid volvulus is a frequent cause of bowel obstruction. The aim of this study was to evaluate the results of acute sigmoid resection and anastomosis via a mini-laparotomy in patients with uncomplicated sigmoid volvulus, following the principles of "Enhanced Recovery After Surgery (ERAS)", in a low-resource setting. Patients with uncomplicated sigmoid volvulus were operated acutely, via a mini-laparotomy, according to the principles of ERAS. Intraoperative complications, duration of operation, morbidity, mortality and length of hospital stay were evaluated, retrospectively. From 1 March 2012 to 1 September 2017, 31 consecutive patients were treated with acute sigmoid resection and anastomosis, via a mini-laparotomy. There were 29 men and 2 women, median age 57 (range 17-92) years. Patients were operated after a median period of 4 (range 1.5-18) hours. The median duration of the operative procedure was 50 (range 30-105) minutes. Two patients died (6.3%). One patient died during an uncomplicated operation. The cause of death is unknown. One patient with a newly diagnosed HIV infection had an anastomotic dehiscence. After Hartmann's procedure, he died on the 17th post-operative day as a result of a HIV-related double-sided pneumonia, without signs of abdominal sepsis. One patient had an urinary retention and 1 patient haematuria after bladder catheter insertion. Acute sigmoid resection and primary anastomosis via a mini-laparotomy for uncomplicated sigmoid volvulus, without preoperative endoscopic decompression is a safe procedure with a low morbidity and mortality.

Update on Thales flexure bearing coolers and drive electronics

NASA Astrophysics Data System (ADS)

Willems, D.; Benschop, T.; v. d. Groep, W.; Mullié, J.; v. d. Weijden, H.; Tops, M.

2009-05-01

Thales Cryogenics has a long background in delivering cryogenic coolers with an MTTF far above 20.000 hrs for military, civil and space programs. Developments in these markets required continuous update of the flexure bearing cooler portfolio for new and emerging applications. The cooling requirements of new application have not only their influence on the size of the compressor, cold finger and cooling technology used but also on the integration and control of the cooler in the application. Thales Cryogenics developed a compact Cooler Drive Electronics based on DSP technology that could be used for driving linear flexure bearing coolers with extreme temperature stability and with additional diagnostics inside the CDE. This CDE has a wide application and can be modified to specific customer requirements. During the presentation the latest developments in flexure bearing cooler technology will be presented both for Stirling and Pulse Tube coolers. Also the relation between the most important recent detector requirements and possible available solutions on cryocooler level will be presented.

Ventral marsupialisation in the treatment of gastric dilatation-volvulus in two dogs.

PubMed

Mills, J

2000-06-01

A ventral marsupialisation technique is described which was used successfully to manage gastric dilatation-volvulus (GDV) in two large breed dogs. The procedure allowed the stomach to be completely and rapidly emptied and lavaged without peritoneal contamination. Drainage was maintained in the postoperative period for both dogs and the technique was expected to result in a permanent ventral gastropexy.

Assessment of two methods of gastric decompression for the initial management of gastric dilatation-volvulus.

PubMed

Goodrich, Z J; Powell, L L; Hulting, K J

2013-02-01

To assess gastric trocarization and orogastric tubing as a means of gastric decompression for the initial management of gastric dilatation-volvulus. Retrospective review of 116 gastric dilatation-volvulus cases from June 2001 to October 2009. Decompression was performed via orogastric tubing in 31 dogs, gastric trocarization in 39 dogs and a combination of both in 46 dogs. Tubing was successful in 59 (75·5%) dogs and unsuccessful in 18 (23·4%) dogs. Trocarization was successful in 73 (86%) dogs and unsuccessful in 12 (14%) dogs. No evidence of gastric perforation was noted at surgery in dogs undergoing either technique. One dog that underwent trocarization had a splenic laceration identified at surgery that did not require treatment. Oesophageal rupture or aspiration pneumonia was not identified in any dog during hospitalization. No statistical difference was found between the method of gastric decompression and gastric compromise requiring surgical intervention or survival to discharge. Orogastric tubing and gastric trocarization are associated with low complication and high success rates. Either technique is an acceptable method for gastric decompression in dogs with gastric dilatation-volvulus. © 2013 British Small Animal Veterinary Association.

An unusual cause of paediatric abdominal pain: Mesenteric masses accompanied with volvulus.

PubMed

Yang, Chao; Wang, Shan; Zhang, Jun; Kong, Xiang Ru; Zhao, Zhenzhen; Li, Chang Chun

2016-07-01

Volvulus caused by mesenteric masses is rare and may result in serious consequences. This study aimed to better characterize volvulus caused by mesenteric masses in children. A retrospective study was conducted in 24 patients who underwent surgical treatment between January 1994 and January 2014 in one single institution. There were 10 boys and 14 girls. The most frequent findings were abdominal pain (100%), emesis (91.7%) and nausea (83.3%). Physical examination showed positive ileus signs in majority cases, and palpable mass was found in half of the patients. Ultrasound and CT scans revealed mesenteric masses in 21 and 24 patients, and 'whirlpool sign' was observed in 19 and 22 patients, respectively. Emergency laparotomy was performed in all patients. Histological examination revealed that 18 cystic masses were lymphangioma, 5 solid cases were lipoma and the remaining one was lipoblastoma. The postoperative course was uneventful in 22 patients, and postoperative obstruction and incision infection occurred in 2 patients. There was no evidence of recurrence at follow-up. Volvulus caused by mesenteric masses is a rare but potentially life-threatening cause of abdominal pain, which should be considered in the differential diagnosis of paediatric acute abdominal pain.

Retinoid Expression in Onchocercal Skin Disease: Pilot Study

PubMed Central

Mawson, Anthony R; Makunde, Williams H; Penman, Alan D; Hernandez Morales, Veronica de Los Angeles; Kalinga, Akili K; Francis, Filbert; Rubinchik, Semyon; Kibweja, Addow

2017-01-01

Based on the observation that the parasite Onchocerca volvulus selectively absorbs vitamin A from the host, and the known toxicity of vitamin A in higher concentration, it was hypothesized that dying microfilariae (mf) release their stores of vitamin A (retinoids) into the host circulation in toxic concentrations, inducing the signs and symptoms of onchocerciasis. We conducted a pilot study to test the hypothesis in Songea communities in Southern Tanzania, where mass drug administration with ivermectin had not been implemented by the time of the survey. The specific aim was to evaluate the correlation between the diagnosis of onchocerciasis and increased levels of retinoic acid at infection sites. The analysis was performed by determining copy numbers of a genome of O volvulus present in skin snip samples of persons with onchocerciacis, and correlating these numbers with expression levels of retinoic acid receptor-α (RAR-α), which is inducible by retinoic acid. Total DNA and RNA were extracted from each of 25 mf-positive and 25 mf-negative skin samples and evaluated using quantitative polymerase chain reaction with appropriate negative controls. Analysis of the samples, adjusted with glyceraldehyde 3-phosphate dehydrogenase gene levels, revealed that most samples with detectable RAR-α transcripts had higher levels of RAR-α expression than the assay control. However, the quality and number of samples were insufficient for statistical analysis. Fold data on the expression levels of both O volvulus DNA and RAR RNA suggested a possible trend toward higher relative RAR-α expression in samples with higher levels of O volvulus DNA (r2 = 0.25, P = .079). Evidence of a contribution of vitamin A to the pathology of onchocerciasis thus remains elusive. Future studies on the role of retinoids in onchocerciasis will require larger groups of participants as well as careful monitoring of the cold chain and tissue storage procedures in view of the sensitivity of vitamin A to heat and light. PMID:29317828

Reproductive Status of Onchocerca volvulus after Ivermectin Treatment in an Ivermectin-Naïve and a Frequently Treated Population from Cameroon

PubMed Central

Bopda, Jean; Kengne-Ouafo, Jonas A.; Njiokou, Flobert; Prichard, Roger K.; Wanji, Samuel; Kamgno, Joseph; Boussinesq, Michel

2014-01-01

Background For two decades, onchocerciasis control has been based on mass treatment with ivermectin (IVM), repeated annually or six-monthly. This drug kills Onchocerca volvulus microfilariae (mf) present in the skin and the eyes (microfilaricidal effect) and prevents for 3–4 months the release of new mf by adult female worms (embryostatic effect). In some Ghanaian communities, the long-term use of IVM was associated with a more rapid than expected skin repopulation by mf after treatment. Here, we assessed whether the embryostatic effect of IVM on O. volvulus has been altered following frequent treatment in Cameroonian patients. Methodology Onchocercal nodules were surgically removed just before (D0) and 80 days (D80) after a standard dose of IVM in two cohorts with different treatment histories: a group who had received repeated doses of IVM over 13 years, and a control group with no history of large-scale treatments. Excised nodules were digested with collagenase to isolate adult worms. Embryograms were prepared with females for the evaluation of their reproductive capacities. Principal Findings Oocyte production was not affected by IVM. The mean number of intermediate embryos (morulae and coiled mf) decreased similarly in the two groups between D0 and D80. In contrast, an accumulation of stretched mf, either viable or degenerating, was observed at D80. However, it was observed that the increase in number of degenerating mf between D0 and D80 was much lower in the frequently treated group than in the control one (Incidence Rate Ratio: 0.25; 95% CI: 0.10–0.63; p = 0.003), which may indicate a reduced sequestration of mf in the worms from the frequently treated group. Conclusion/Significance IVM still had an embryostatic effect on O. volvulus, but the effect was reduced in the frequently treated cohort compared with the control population. PMID:24762816

Retinoid Expression in Onchocercal Skin Disease: Pilot Study.

PubMed

Mawson, Anthony R; Makunde, Williams H; Penman, Alan D; Hernandez Morales, Veronica de Los Angeles; Kalinga, Akili K; Francis, Filbert; Rubinchik, Semyon; Kibweja, Addow

2017-01-01

Based on the observation that the parasite Onchocerca volvulus selectively absorbs vitamin A from the host, and the known toxicity of vitamin A in higher concentration, it was hypothesized that dying microfilariae (mf) release their stores of vitamin A (retinoids) into the host circulation in toxic concentrations, inducing the signs and symptoms of onchocerciasis. We conducted a pilot study to test the hypothesis in Songea communities in Southern Tanzania, where mass drug administration with ivermectin had not been implemented by the time of the survey. The specific aim was to evaluate the correlation between the diagnosis of onchocerciasis and increased levels of retinoic acid at infection sites. The analysis was performed by determining copy numbers of a genome of O volvulus present in skin snip samples of persons with onchocerciacis, and correlating these numbers with expression levels of retinoic acid receptor-α (RAR-α), which is inducible by retinoic acid. Total DNA and RNA were extracted from each of 25 mf-positive and 25 mf-negative skin samples and evaluated using quantitative polymerase chain reaction with appropriate negative controls. Analysis of the samples, adjusted with glyceraldehyde 3-phosphate dehydrogenase gene levels, revealed that most samples with detectable RAR-α transcripts had higher levels of RAR-α expression than the assay control. However, the quality and number of samples were insufficient for statistical analysis. Fold data on the expression levels of both O volvulus DNA and RAR RNA suggested a possible trend toward higher relative RAR-α expression in samples with higher levels of O volvulus DNA ( r 2  = 0.25, P  = .079). Evidence of a contribution of vitamin A to the pathology of onchocerciasis thus remains elusive. Future studies on the role of retinoids in onchocerciasis will require larger groups of participants as well as careful monitoring of the cold chain and tissue storage procedures in view of the sensitivity of vitamin A to heat and light.

[Volvulus of the small bowel due to ascaris lumbricoides package: about a case].

PubMed

Diouf, Cheikh; Kane, Ahmed; Ndoye, Ndeye Aby; Ndour, Oumar; Faye-Fall, Aimé Lakh; Fall, Mbaye; Alumeti, Désiré Munyali; Ngom, Gabriel

2016-01-01

We report an exceptional case of a 7 year-old patient with necrotic small bowel volvulus due to adult ascaris lumbricoides. At the admission, the child had intestinal obstruction evolving since two days with alteration of general state. Abdominal radiography without preparation showed small bowel air-fluid levels and tiger-stripe appearance evoking the diagnosis of acute intestinal obstruction associated with abdominal mass. After resuscitation, the surgical treatment consisted of laparotomy which showed necrotic volvulus of the terminal ileum containing adult ascaris lumbricoides. The patient underwent small bowel resection, approximately one meter of affected section was removed and then an ileostomy was performed. The evolution was favorable. The patient underwent ileorectal anastomosis four weeks later. After a 2 year follow-up period the child had no symptoms.

The volumetric fraction of inorganic particles and the flexural strength of composites for posterior teeth.

PubMed

Adabo, Gelson Luis; dos Santos Cruz, Carlos Alberto; Fonseca, Renata Garcia; Vaz, Luís Geraldo

2003-07-01

To evaluate the content of inorganic particles and the flexural strength of new condensable composites for posterior teeth in comparison to hybrid conventional composites. The determination of the content of inorganic particles was performed by mass weighing of a polymerized composite before and after the elimination of the organic phase. The volumetric particle content was determined by a practical method based on Archimedes' principle, which calculates the volume of the composite and their particles by differential mass measured in the air and in water. The flexural strength of three points was evaluated according to the norm ISO 4049:1988. The results showed the following filler content: Alert, 67.26%; Z-100, 65.27%; Filtek P 60, 62.34%; Ariston pHc, 64.07%; Tetric Ceram, 57.22%; Definite, 54.42%; Solitaire, 47.76%. In the flexural strength test, the materials presented the following decreasing order of resistance: Filtek P 60 (170.02 MPa)>Z-100 (151.34 MPa)>Tetric Ceram (126.14 MPa)=Alert (124.89 MPa)>Ariston pHc (102.00 MPa)=Definite (93.63 MPa)>Solitaire (56.71 MPa). New condensable composites for posterior teeth present a concentration of inorganic particles similar to those of hybrid composites but do not necessarily present higher flexural strength.

Case study of flexure and shear strengthening of RC beams by CFRP using FEA

NASA Astrophysics Data System (ADS)

Jankowiak, Iwona

2018-01-01

In the paper the preliminary results of study on strengthening RC beams by means of CFRP materials under mixed shear-flexural work condition are presented. The Finite Element Method analyses were performed using numerical models proposed and verified earlier by the results of laboratory tests [4, 5] for estimation of effectiveness of CFRP strengthening of RC beams under flexure. The currently conducted analyses deal with 3D models of RC beams under mixed shear-flexural loading conditions. The symmetry of analyzed beams was taken into account (in both directions). The application of Concrete Damage Plasticity (CDP) model of RC beam allowed to predict a layout and propagation of cracks leading to failure. Different cases of strengthening were analyzed: with the use of CFRP strip or CFRP closed hoops as well as with the combination of above mentioned. The preliminary study was carried out and the first results were presented.

Compliance and control characteristics of an additive manufactured-flexure stage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, ChaBum; Tarbutton, Joshua A.

2015-04-15

This paper presents a compliance and positioning control characteristics of additive manufactured-nanopositioning system consisted of the flexure mechanism and voice coil motor (VCM). The double compound notch type flexure stage was designed to utilize the elastic deformation of two symmetrical four-bar mechanisms to provide a millimeter-level working range. Additive manufacturing (AM) process, stereolithography, was used to fabricate the flexure stage. The AM stage was inspected by using 3D X-ray computerized tomography scanner: air-voids and shape irregularity. The compliance, open-loop resonance peak, and damping ratio of the AM stage were measured 0.317 mm/N, 80 Hz, and 0.19, respectively. The AM stagemore » was proportional-integral-derivative positioning feedback-controlled and the capacitive type sensor was used to measure the displacement. As a result, the AM flexure mechanism was successfully 25 nm positioning controlled within 500 μm range. The resonance peak was found approximately at 280 Hz in closed-loop. This research showed that the AM flexure mechanism and the VCM can provide millimeter range with high precision and can be a good alternative to an expensive metal-based flexure mechanism and piezoelectric transducer.« less

A retrospective study of factors influencing survival following surgery for gastric dilatation-volvulus syndrome in 306 dogs.

PubMed

Mackenzie, George; Barnhart, Mathew; Kennedy, Shawn; DeHoff, William; Schertel, Eric

2010-01-01

Gastric dilatation-volvulus (GDV) is a life-threatening condition in dogs that has been associated with high mortality rates in previous studies. Factors were evaluated in this study for their influence on overall and postoperative mortality in 306 confirmed cases of GDV between 2000 and 2004. The overall mortality rate was 10%, and the postoperative mortality rate was 6.1%. The factor that was associated with a significant increase in overall mortality was the presence of preoperative cardiac arrhythmias. Factors that were associated with a significant increase in postoperative mortality were postoperative cardiac arrhythmias, splenectomy, or splenectomy with partial gastric resection. The factor that was associated with a significant decrease in the overall mortality rate was time from presentation to surgery. This study documents that certain factors continue to affect the overall and postoperative mortality rates associated with GDV, but these mortality rates have decreased compared to previously reported rates.

Acute gastric dilatation and volvulus in a free-living polar bear

USGS Publications Warehouse

Amstrup, Steven C.; Nielsen, Carol A.

1989-01-01

A large, adult male polar bear (Ursus maritimus) was found dead on a barrier island north of Prudhoe Bay, Alaska (USA), in June 1987. There were no external signs of trauma. A twisted distended stomach, distinctive parenchymal and fascial congestion, and significant difficulty in repositioning the anterior abdominal organs, indicated that gastric dilatation-volvulus (GDV) was the proximate cause of death. Polar bears frequently consume large quantities of food at one time and have large stomachs that are well adapted to periodic gorging. The scarcity of food in winter and early spring, combined with voluntary fasting and protracted vigorous activity during the breeding season in late spring may have predisposed this bear to GDV. The relationship between GDV and postprandial exercise emphasizes the need for a better understanding of how the present human invasion of arctic habitats may influence polar bear activities.

Genetic selection of low fertile Onchocerca volvulus by ivermectin treatment.

PubMed

Bourguinat, Catherine; Pion, Sébastien D S; Kamgno, Joseph; Gardon, Jacques; Duke, Brian O L; Boussinesq, Michel; Prichard, Roger K

2007-08-30

Onchocerca volvulus is the causative agent of onchocerciasis, or "river blindness". Ivermectin has been used for mass treatment of onchocerciasis for up to 18 years, and recently there have been reports of poor parasitological responses to the drug. Should ivermectin resistance be developing, it would have a genetic basis. We monitored genetic changes in parasites obtained from the same patients before use of ivermectin and following different levels of ivermectin exposure. O. volvulus adult worms were obtained from 73 patients before exposure to ivermectin and in the same patients following three years of annual or three-monthly treatment at 150 microg/kg or 800 microg/kg. Genotype frequencies were determined in beta-tubulin, a gene previously found to be linked to ivermectin selection and resistance in parasitic nematodes. Such frequencies were also determined in two other genes, heat shock protein 60 and acidic ribosomal protein, not known to be linked to ivermectin effects. In addition, we investigated the relationship between beta-tubulin genotype and female parasite fertility. We found a significant selection for beta-tubulin heterozygotes in female worms. There was no significant selection for the two other genes. Quarterly ivermectin treatment over three years reduced the frequency of the beta-tubulin "aa" homozygotes from 68.6% to 25.6%, while the "ab" heterozygotes increased from 20.9% to 69.2% in the female parasites. The female worms that were homozygous at the beta-tubulin locus were more fertile than the heterozygous female worms before treatment (67% versus 37%; p = 0.003) and twelve months after the last dose of ivermectin in the groups treated annually (60% versus 17%; p<0.001). Differences in fertility between heterozygous and homozygous worms were less apparent three months after the last treatment in the groups treated three-monthly. The results indicate that ivermectin is causing genetic selection on O. volvulus. This genetic selection is associated with a lower reproductive rate in the female parasites. We hypothesize that this genetic selection indicates that a population of O. volvulus, which is more tolerant to ivermectin, is being selected. This selection could have implications for the development of ivermectin resistance in O. volvulus and for the ongoing onchocerciasis control programmes.

Determination of service stresses in pretensioned beams, final report, December 2009.

DOT National Transportation Integrated Search

2009-12-01

This report presents research on the evaluation of service flexural stresses and cracking moment in prestressed concrete members and on the minimum reinforcement requirements that are currently controlled by the flexural cracking moment. In prestress...

[Dolichomegacolon of the Andes and intestinal volvulus due to altitude].

PubMed

Frisancho, Oscar

2008-01-01

Sigmoid volvulus is a frequent cause of emergencies in hospitals in the Andean area, representing more than 50% of all intestinal obstructions. Andean dolichomegacolon (DCMA) and retractile mesocolonitis are the main contributing factors for volvulus. The mesocolonitis nears the proximal and distal segment of the sigmoid handle, favoring its torsion. Copious intake of fermentable food is the precipitating factor for volvulus. The majority of patients are seen during sowing and harvest periods, in which the consumption of this type of food increases. Andean people who live at an altitude of 3,000 m have a larger and thicker colon than coastal residents. We call this acquired characteristic the Andean dolichomegacolon (DCMA). A fiber-rich diet may inhibit the histological phenomenon known as elastogenesis, developing--over the years--the megacolon. Another important factor may be the lower atmospheric pressure in the altitude, and according to Boyle and Mariotte's physical law, the expansion of intraluminal gas may have an influence on intestinal enlargement. DCMA has many special anatomic, clinical, radiological, histological and serological features which make it different from the . chagasic megacolon. Mild emergency procedures may be performed to treat the sigmoid volvulus, such as endoscopic disvolvulation. Changing the colon rotation is helpful in diminishing abdominal pressure and restore complete blood circulation. An emergency surgery treatment must take the patient's general condition and the colon handle condition during surgery as a guiding point. High rates of mortality are found in relation to elderly patients, disease evolution time and stage of intestinal ischemia. Other new therapeutic procedures such as percutaneous sigmoidpexy, laparoscopic sigmoidectomy and mesosigmoplasty are under review, and have precise indications. Wider series are needed to evaluate them better.

More patients should undergo surgery after sigmoid volvulus.

PubMed

Ifversen, Anne Kathrine Wewer; Kjaer, Daniel Willy

2014-12-28

To assess the outcome of patients treated conservatively vs surgically during their first admission for sigmoid volvulus. We conducted a retrospective study of 61 patients admitted to Aarhus University Hospital in Denmark between 1996 and 2011 for their first incidence of sigmoid volvulus. The condition was diagnosed by radiography, sigmoidoscopy or surgery. Patients treated with surgery underwent either a sigmoid resection or a percutaneous endoscopic colostomy (PEC). Conservatively treated patients were managed without surgery. Data was recorded into a Microsoft Access database and calculations were performed with Microsoft Excel. Kaplan-Meier plotting and Mantel-Cox (log-rank) testing were performed using GraphPad Prism software. Mortality was defined as death within 30 d after intervention or surgery. Among the total 61 patients, 4 underwent emergency surgery, 55 underwent endoscopy, 1 experienced resolution of the volvulus after contrast enema, and 1 died without treatment because of large bowel perforation. Following emergency treatment, 28 patients underwent sigmoid resection (semi-elective n = 18; elective n = 10). Two patients who were unfit for surgery underwent PEC and both died, 1 after 36 d and the other after 9 mo, respectively. The remaining 26 patients were managed conservatively without sigmoid resection. Patients treated conservatively on their first admission had a poorer survival rate than patients treated surgically on their first admission (95%CI: 3.67-14.37, P = 0.036). Sixty-three percent of the 26 conservatively treated patients had not experienced a recurrence 3 mo after treatment, but that number dropped to 24% 2 years after treatment. Eight of the 14 patients with recurrence after conservative treatment had surgery with no 30-d mortality. Surgically-treated sigmoid volvulus patients had a higher long-term survival rate than conservatively managed patients, indicating a benefit of surgical resection or PEC insertion if feasible.

More patients should undergo surgery after sigmoid volvulus

PubMed Central

Ifversen, Anne Kathrine Wewer; Kjaer, Daniel Willy

2014-01-01

AIM: To assess the outcome of patients treated conservatively vs surgically during their first admission for sigmoid volvulus. METHODS: We conducted a retrospective study of 61 patients admitted to Aarhus University Hospital in Denmark between 1996 and 2011 for their first incidence of sigmoid volvulus. The condition was diagnosed by radiography, sigmoidoscopy or surgery. Patients treated with surgery underwent either a sigmoid resection or a percutaneous endoscopic colostomy (PEC). Conservatively treated patients were managed without surgery. Data was recorded into a Microsoft Access database and calculations were performed with Microsoft Excel. Kaplan-Meier plotting and Mantel-Cox (log-rank) testing were performed using GraphPad Prism software. Mortality was defined as death within 30 d after intervention or surgery. RESULTS: Among the total 61 patients, 4 underwent emergency surgery, 55 underwent endoscopy, 1 experienced resolution of the volvulus after contrast enema, and 1 died without treatment because of large bowel perforation. Following emergency treatment, 28 patients underwent sigmoid resection (semi-elective n = 18; elective n = 10). Two patients who were unfit for surgery underwent PEC and both died, 1 after 36 d and the other after 9 mo, respectively. The remaining 26 patients were managed conservatively without sigmoid resection. Patients treated conservatively on their first admission had a poorer survival rate than patients treated surgically on their first admission (95%CI: 3.67-14.37, P = 0.036). Sixty-three percent of the 26 conservatively treated patients had not experienced a recurrence 3 mo after treatment, but that number dropped to 24% 2 years after treatment. Eight of the 14 patients with recurrence after conservative treatment had surgery with no 30-d mortality. CONCLUSION: Surgically-treated sigmoid volvulus patients had a higher long-term survival rate than conservatively managed patients, indicating a benefit of surgical resection or PEC insertion if feasible. PMID:25561806

Role of the ultrasonographic 'whirlpool sign' in intestinal volvulus: a systematic review and meta-analysis.

PubMed

Enyuma, Callistus O A; Adam, Ahmed; Aigbodion, Sunday J; McDowall, Jared; Gerber, Louis; Buchanan, Sean; Laher, Abdullah E

2018-05-08

Intestinal volvulus is a potentially life-threatening condition that occurs when loops of bowel twist around its supporting mesentery and associated vasculature. Clinicians often rely on various radiological investigations for prompt diagnosis to avoid complications such as bowel infarction. This review assesses the clinical reliability of the ultrasonographic whirlpool sign (WS) in the diagnosis of intestinal volvulus. In adherence with the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-analyses) statement, a systematic search of BMJ Best Practice, Cochrane Database of Systematic Reviews, EMBASE, Google Scholar, PubMed, Scopus and Web of Science databases was performed (August 2017), using relevant search terms. Selected studies were ranked for quality and relevance using the CASP (Critical Appraisal Skills Program) tool. Sixteen articles (1640 participants) were assessed. The mean and median sample size was 102.5 (SD ± 192.23) and 28 (range 7-770), respectively. The WS was positive in 212 of 255 (83.1%) patients with intestinal volvulus. Meta-analysis of the studies that provided sufficient data resulted in a pooled sensitivity and specificity of 87.42% (95% confidence interval (CI): 81.05-92.25) and 98.63% (95% CI: 97.88-99.18), respectively, with an estimated summary effect of 5.28 (95% CI: 4.47-6.08, P < 0.001). There was negligible inter-study heterogeneity, which was suggested by an I 2 statistic of 0% (95% CI: 0.00-76.34) and a τ 2 parameter of 0 (95% CI: 0.00-5.35). Though the pooled sensitivity was less than ideal (87.42%), this review and meta-analysis nevertheless supports the reliability of the ultrasonographic WS as an acceptable indicator of intestinal volvulus. © 2018 Royal Australasian College of Surgeons.

Flexural eczema versus atopic dermatitis.

PubMed

Jacob, Sharon E; Goldenberg, Alina; Nedorost, Susan; Thyssen, Jacob P; Fonacier, Luz; Spiewak, Radoslaw

2015-01-01

Flexural eczema and atopic dermatitis are frequently synonymized. As respiratory atopy is rarely tested for and found in these patients, systematically equating a flexural distribution of dermatitis with atopic dermatitis may too frequently result in misclassified diagnoses and potentially missed opportunity for intervention toward improving patients' symptoms and quality of life. We present a critical review of the available evidence for the atopic dermatitis diagnosis and discuss the similarities between atopic dermatitis and allergic contact dermatitis. Because neither flexural predilection nor atopy is specific for atopic dermatitis, we conclude that the term atopic dermatitis is a misnomer and propose an etymologic reclassification of atopic dermatitis to "atopy-related" dermatitis. Allergic contact dermatitis can induce an atopic dermatitis-like phenotype, and thus, flexural dermatitis cannot be assumed as atopic without further testing. Patch testing should at least be considered in cases of chronic or recurrent eczema regardless of the working diagnosis.

Thermal stresses, differential subsidence, and flexure at oceanic fracture zones

NASA Technical Reports Server (NTRS)

Wessel, Pal; Haxby, William F.

1990-01-01

Geosat geoid undulations over four Pacific fracture zones have been analyzed. After correcting for the isostatic thermal edge effect, the amplitudes of the residuals are shown to be proportional to the age offset. The shape of the residuals seems to broaden with increasing age. Both geoid anomalies and available ship bathymetry data suggest that slip must sometimes occur on the main fracture zone or secondary faults. Existing models for flexure at fracture zones cannot explain the observed anomalies. A combination model accounting for slip and including flexure from thermal stresses and differential subsidence is presented. This model accounts for lateral variations in flexural rigidity from brittle and ductile yielding due to both thermal and flexural stresses and explains both the amplitudes and the shape of the anomalies along each fracture zone. The best fitting models have mechanical plate thicknesses that are described by the depth to the 600-700 C isotherms.

Prenatal Diagnosis of a Segmental Small Bowel Volvulus with Threatened Premature Labor

PubMed Central

Mottet, Nicolas; Ramanah, Rajeev; Riethmuller, Didier

2017-01-01

Fetal primary small bowel volvulus is extremely rare but represents a serious life-threatening condition needing emergency neonatal surgical management to avoid severe digestive consequences. We report a case of primary small bowel volvulus with meconium peritonitis prenatally diagnosed at 27 weeks and 4 days of gestation during threatened premature labor with reduced fetal movements. Ultrasound showed a small bowel mildly dilated with thickened and hyperechogenic intestinal wall, with a typical whirlpool configuration. Normal fetal development allowed continuation of pregnancy with ultrasound follow-up. Induction of labor was decided at 37 weeks and 2 days of gestation because of a significant aggravation of intestinal dilatation appearing more extensive with peritoneal calcifications leading to the suspicion of meconium peritonitis, associated with reduced fetal movements and reduced fetal heart rate variability, for neonatal surgical management with a good outcome. PMID:29230337

Intestinal volvulus with coagulative hepatic necrosis in a chicken.

PubMed

Haridy, Mohie; Goryo, Masanobu; Sasaki, Jun; Okada, Kosuke

2010-04-01

A 7-week-old SPF chicken inoculated at 4 weeks of age with chicken anemia virus was puffed up depressed and had ruffled feathers and a good body condition. Intestinal volvulus involving the jejunum and part of the duodenum forming two loops with one knob was observed. Microscopically, venous infarction of the obstructed loops, periportal and sublobular multifocal coagulative hepatic necrosis and granulomatous inflammation of the cecal tonsils were observed. Gram staining revealed no bacteria in hepatic tissue; however, gram-positive bacilli were detected in the necrotic debris in the intestinal lumen. Immunosuppression might have predisposed the chicken to intestinal and cecal tonsil infection that then progressed to volvulus. Loss of the mucosal barrier in infarction might allow bacterial toxins and vasoactive factors to escape into the systemic circulation (toxemia) and be responsible for the hepatic necrosis.

Estimating flexural rigidity and load magnitude required for formation of Ross Island flexure moat

NASA Astrophysics Data System (ADS)

Jha, S.; Harry, D. L.; Wenman, C. P.

2017-12-01

Lithospheric flexural subsidence around Ross Island in West Antarctica led to formation of the Ross Island flexure moat. This subsidence was caused by two major volcanic phases on Ross Island. The first phase saw the first surficial expression of Ross Island and volcanism at Mt. Bird to the north of Ross Island, which lasted from 5.2 - 2.9 Ma. The second phase lasted from 1.78 Ma to present and is comprised of eruptions from Mt. Terror to the east, Mt. Erebus to the west and Hut Point Peninsula (HPP) to the south of Ross Island. Flexural subsidence of the lithosphere due to volcanism on Ross Island led to formation of a sedimentary moat around the island, which is preserved in stratigraphy imaged on seismic reflection profiles. We identified 5 unconformities (from deepest upward Ri, RMU1, RMU2, RMU3, RMU4) in the seismic surveys which correspond to flexural subsidence episodes around Ross Island since early Pliocene. Ri (4.4 Ma) lies near the bottom of the flexural moat and RMU4 near the seafloor and top of the moat fill. These unconformities were used to make isopach maps to constrain flexure modeling of the area. Isopach maps show circular or semi-circular flexure basins around Ross Island which is approximated using a continuous plate, point load flexure model. We used Ri - sea floor isopach to constrain flexure models for 5 profiles centered on 4 volcanic centers and trending radially out of Ross Island. Flexure models along two profiles beginning on Mt. Bird and one profile off HPP show a flexural rigidity range of 1.47 - 6.44 x 1018 Nm with load center of mass on Mt. Bird and on HPP, respectively. A similar model along a profile initiating on Mt. Terror, passing through Mt Erebus and extending west of Ross Island across the moat, yielded a higher flexural rigidity estimate of 2.03 x 1019 Nm with load centered at Mt. Erebus. A flexure model to the north east of Ross Island along a profile beginning at Mt Terror and trending north, provide the highest flexural rigidity estimate of 6.9 x 1019 Nm. The load magnitudes determined from these flexure models lie in the range of 4.6 x 1015 N - 4.3 x 1016 N. This is less than the topographic load (6.9 x 1017 N estimated from BEDMAP2) produced by the island by one to two orders of magnitude. The difference in load magnitudes suggest anomalously low densities caused by high lower crust and mantle temperatures in the region.

EFFECTS OF CYCLIC FLEXURAL FATIGUE ON PORCINE BIOPROSTHETIC HEART VALVE HETEROGRAFT BIOMATERIALS

PubMed Central

Mirnajafi, Ali; Zubiate, Brett; Sacks, Michael S.

2009-01-01

While bioprosthetic heart valves (BHV) remain the primary treatment modality for adult heart valve replacement, continued problems with durability remain. Several studies have implicated flexure as a major damage mode in porcine-derived heterograft biomaterials used in BHV fabrication. While conventional accelerated wear testing can provide valuable insights into BHV damage phenomena, the constituent tissues are subjected to complex, time-varying deformation modes (i.e. tension and flexure), that do not allow for the control of the amount, direction, and location of flexure. Thus, in the present study customized fatigue testing devices were developed to subject circumferentially oriented porcine BHV tissue strips to controlled cyclic flexural loading. By using this approach, we were able to study layer-specific structural damage induced by cyclic flexural tensile and compressive stresses alone. 10×106, 25×106 and 50×106 cycle levels were used, with resulting changes in flexural stiffness and collagen structure assessed. Results indicated that flexural rigidity was markedly reduced after only 10×106 cycles, and progressively decayed at a lower rate with cycle number thereafter. Moreover, the against-curvature fatigue direction induced the most damage, suggesting that the ventricularis and fibrosa layers have low resistance to cyclic flexural compressive and tensile loads, respectively. The histological analyses indicated progressive collagen fiber delamination as early as 10×106 cycles, but otherwise no change in gross collagen orientation. Our results underscore that porcine-derived heterograft biomaterials are very sensitive to flexural fatigue, with delamination of the tissue layers the primary underlying mechanism. This appears to be in contrast to pericardial BHV, wherein high tensile stresses are considered to be the major cause of structural failure. These findings point towards the need for the development of chemical fixation technologies that minimize flexure induced damage to extend porcine heterograft biomaterial durability. PMID:20166221

Effect of flexure beam geometry and material on the displacement of piezo actuated diaphragm for micropump

NASA Astrophysics Data System (ADS)

Roopa, R.; Navin Karanth, P.; Kulkarni, S. M.

2018-02-01

In this paper, we present a COMSOL analysis of flexure diaphragm for piezo actuated valveless micropump. Diaphragms play an important role in micropumps, till now plane diaphragms are commonly used in micropumps. Use of compliant flexure hinges in diaphragm and other MEMS application is one of the new approach to achieving high deflection in diaphragm at low operating voltage. Flexures hinges in diaphragm acts as simply supported beam. Out-off plane compliance value and stiffness is considered for the selection of proper flexure for diaphragm. Diaphragm material also plays an important role in the diaphragm central deflection. Factor considered for diaphragm material selection is resilience; it is the ratio of yield stress to static modulus. Higher is the resilience will leads to higher deflection generated, it also imparts good compliance. Based on the resilience beryllium copper, stainless steel and brass materials are selected for diaphragm analysis. Simulations have been performed using COMSOL multiphysics. This study reports the effect of flexure hinge geometry and diaphragm material on the central deflection of diaphragms and compared with existing plane diaphragm. Simulation results illustrates that the deflection of three flexure diaphragm with 2mm width and 2mm length flexure is 6.75µm for stainless steel, 10.89 for beryllium copper and 12.10µm for brass, at 140V which is approximately twice that of plane diaphragm deflection. The maximum in both plane and three flexure diaphragm deflection is obtained for brass diaphragm compared to stainless steel and beryllium copper.

Gastric Dilatation and Volvulus in a Red Panda (Ailurus fulgens)

PubMed Central

Neilsen, Colleen; Mans, Christoph; Colopy, Sara A.

2014-01-01

A 12-year-old male red panda (Ailurus fulgens) was evaluated for acute onset inappetance, staggering, collapse, and tachypnea. Gastric dilatation and volvulus (GDV) was diagnosed by radiography, abdominal ultrasonography, and exploratory celiotomy. Torsion of the stomach was corrected and an incisional gastropexy performed to prevent recurrence. No organs were devitalized, no other abnormalities detected, and the red panda recovered fully within 72 hours. PMID:24467661

Concurrent gall bladder, liver lobe torsion, and bile peritonitis in a German shepherd dog 2 months after gastric dilatation/volvulus gastropexy and splenectomy.

PubMed

Tubby, Kurtis G

2013-08-01

Postmortem examination of a 7-year-old German shepherd dog which had gastric dilatation/volvulus and splenectomy 2 months earlier revealed that the right middle and quadrate liver lobes were diffusely congested and torsed. The gall bladder was grossly distended and torsed along its long axis and there was evidence of bile peritonitis.

Ileocecocolic volvulus in a German shepherd dog

PubMed Central

Javard, Romain; Specchi, Swan; Benamou, Jérôme; Lapointe, Catherine; Deffontaines, Jean-Baptiste; Planté, Jérôme; d’Anjou, Marc-André

2014-01-01

This report describes an ileocecocolic volvulus in a German shepherd dog with risk factors of previous abdominal surgeries and concurrent chronic enteropathy. Contrast-enhanced computed tomography (CT) with multiplanar reformatting was more sensitive than abdominal radiographs or ultrasound to obtain a diagnosis, because of the presence of a “whirl-sign” on CT. A combination of colopexy and cecopexy was succesfully used to treat the patient’s condition. PMID:25392556

Onchocerciasis-related epilepsy? Prospects at a time of uncertainty.

PubMed

Marin, Benoît; Boussinesq, Michel; Druet-Cabanac, Michel; Kamgno, Joseph; Bouteille, Bernard; Preux, Pierre-Marie

2006-01-01

Epilepsy and onchocerciasis (river blindness) constitute serious public health problems in several tropical countries. There are four main mechanisms that might explain a relationship between these two diseases: (i) the presence of Onchocerca volvulus in the central nervous system; (ii) the pathogenicity of various O. volvulus strains; (iii) immunological mechanisms involving cross-reactive immunization or cytokine production during infection; and (iv) the triggering role of insomnia due to itching.

Concurrent gall bladder, liver lobe torsion, and bile peritonitis in a German shepherd dog 2 months after gastric dilatation/volvulus gastropexy and splenectomy

PubMed Central

Tubby, Kurtis G.

2013-01-01

Postmortem examination of a 7-year-old German shepherd dog which had gastric dilatation/volvulus and splenectomy 2 months earlier revealed that the right middle and quadrate liver lobes were diffusely congested and torsed. The gall bladder was grossly distended and torsed along its long axis and there was evidence of bile peritonitis. PMID:24155480

Immunohistological studies on neoplasms of female and male Onchocerca volvulus: filarial origin and absence of Wolbachia from tumor cells

PubMed Central

BRATTIG, N. W.; HOERAUF, A.; FISCHER, P. U.; LIEBAU, E.; BANDI, C.; DEBRAH, A.; BÜTTNER, M.; BÜTTNER, D. W.

2010-01-01

SUMMARY Up to 5% of untreated female Onchocerca volvulus filariae develop potentially fatal pleomorphic neoplasms, whose incidence is increased following ivermectin treatment. We studied the occurrence of 8 filarial proteins and of Wolbachia endobacteria in the tumor cells. Onchocercomas from patients, untreated and treated with antibiotics and anthelminthics, were examined by immunohistology. Neoplasms were diagnosed in 112 of 3587 female and in 2 of 1570 male O. volvulus. The following proteins and other compounds of O. volvulus were expressed in the cells of the neoplasms: glutathione S-transferase 1, lysosomal aspartic protease, cAMP-dependent protein kinase, alpha-enolase, aspartate aminotransferase, ankyrin E1, tropomyosin, heat shock protein 60, transforming growth factor-beta, and prostaglandin E2. These findings prove the filarial origin of the neoplasms and confirm the pleomorphism of the tumor cells. Signs indicating malignancy of the neoplasms are described. Wolbachia were observed in the hypodermis, oocytes, and embryos of tumor-harbouring filariae using antibodies against Wolbachia surface protein, Wolbachia HtrA-type serine protease, and Wolbachia aspartate aminotransferase. In contrast, Wolbachia were not found in the cells of the neoplasms. Further, neoplasm-containing worms were not observed after more than 10 months after the start of sufficient treatment with doxycycline or doxycycline plus ivermectin. PMID:20199697

[A right sided colon volvulus with necrosis in a young patient. A case reported].

PubMed

Márquez-Díaz, Adrián; Ramírez-Ortega, Miguel Angel

2010-01-01

Colon volvulus (CV) is the twisting or rotation of an intestinal segment over the mesenterium, which causes occlusion and vascular compromise. It is a frequent disease in individuals over 65 years-old. We report a young patient with right CV and necrosis. A 17 year-old male with clinical findings of acute abdomen presented in the emergency room. During the surgical procedure, a right sided was found, CV with ileocecal valve and caecum ischemia and right colon necrosis with mesenteric vessels thrombosis. The case presented begun with sudden abdominal pain, with intestinal occlusion data, and widespread peritoneal rebound tenderles which suggested an intestinal occlusion. A simple abdomen Rx showed prominent right side colon distention with air levels in small bowel and a "coffee bean" image, suggestive of CVA hemicolectomy with termino-lateral ileocolic anastomosis was performed. Right-sided CV is considered as congenital in origin. They corresponded to 21% of cases in Mexico, with an average age of presentation at 62 years. The CV represents 10% of the causes of large bowel obstruction in Mexico. This is the first case in young people reported in Mexican literature.

Seismic Stratigraphy of the Ross Island Flexural Basin, West Antarctica

NASA Astrophysics Data System (ADS)

Wenman, C. P.; Harry, D. L.; Jha, S.

2014-12-01

Marine seismic reflection data collected over the past 30+ years in the Ross Sea region of southwest Antarctica has been tied to the ANDRILL and CIROS boreholes to develop a seismic stratigraphic model that constrains the spatial and temporal evolution of the flexural basin surrounding Ross Island. Ross Island was formed from 4.6 Ma to present by extrusive volcanism in the Ross Sea at the southern end of the Terror Rift. Preliminary mapping has identified a hinge zone trending northeastward from Mt. Bird, separating the well-developed flexural moat on the west side of the island from sub-horizontal strata on the northeast and east sides. The flexural moat on the west and north-northwest sides of the island is approximately 40-45 km wide with sediment fill thickness of roughly 1100 m. Seismic lines to the east and northeast of the island do not indicate the presence of a flexural moat. Instead, the thickness of strata on the east side of the island that are time-equivalent to the infill of the flexural moat on the west side remains constant from the Coulman High westward to within ~28 km of Ross Island (the landward extent of the seismic data coverage). The concordant post-Miocene strata on the east and northeast sides of Ross Island imply either that the flexural basin does not extend more than ~28 km eastward from the Ross Island shoreline, or that the flexural basin is not present on that side of the island. The first scenario requires that the elastic strength of the lithosphere differ on either side of the hinge. The second scenario can be explained by a mechanical rupture in the lithosphere beneath Ross Island, with Ross Island acting as an end-load on a mechanical half-plate that forms the lithosphere beneath Ross Island and westward. In this model, the lithosphere east of Ross Island and the hinge forms a second half-plate, bearing little or none of the Ross Island volcanic load.

Effects of porcelain thickness on the flexural strength and crack propagation in a bilayered zirconia system.

PubMed

Figueiredo, Viviane Maria Gonçalves de; Pereira, Sarina Maciel Braga; Bressiani, Eduardo; Valera, Márcia Carneiro; Bottino, Marco Antônio; Zhang, Yu; Melo, Renata Marques de

2017-01-01

This study evaluated the influence of porcelain (VM9, VITA Zahnfabrik, Germany) thickness on the flexural strength and crack propagation in bilayered zirconia systems (YZ, VITA Zahnfabrik, Germany). Thirty zirconia bars (20.0x4.0x1.0 mm) and six zirconia blocks (12.0x7.5x1.2 mm) were prepared and veneered with porcelain with different thickness: 1 mm, 2 mm, or 3 mm. The bars of each experimental group (n=10) were subjected to four-point flexural strength testing. In each ceramic block, a Vickers indentation was created under a load of 10 kgf for 10 seconds, for the propagation of cracks. The results of flexural strength were evaluated by One-way ANOVA and Tukey's test, with a significance level of 5%. The factor "thickness of the porcelain" was statistically significant (p=0.001) and the l-mm group presented the highest values of flexural strength. The cracks were predominant among the bending specimens with 1 and 2 mm of porcelain, and catastrophic failures were found in 50% of 3-mm-thick porcelain. After the indentation of blocks, the most severe defects were observed in blocks with 3-mm-thick porcelain. The smallest (1 mm) thickness of porcelain on the zirconia infrastructure presented higher values of flexural strength. Better resistance to defect propagation was observed near the porcelain/ zirconia interface for all groups. Higher flexural strength was found for a thinner porcelain layer in a bilayered zirconia system. The damage caused by a Vickers indentation near and far the interface with the zirconia shows that the stress profiles are different.

Effects of porcelain thickness on the flexural strength and crack propagation in a bilayered zirconia system

PubMed Central

de Figueiredo, Viviane Maria Gonçalves; Pereira, Sarina Maciel Braga; Bressiani, Eduardo; Valera, Márcia Carneiro; Bottino, Marco Antônio; Zhang, Yu; de Melo, Renata Marques

2017-01-01

Abstract Objective: This study evaluated the influence of porcelain (VM9, VITA Zahnfabrik, Germany) thickness on the flexural strength and crack propagation in bilayered zirconia systems (YZ, VITA Zahnfabrik, Germany). Material and Methods: Thirty zirconia bars (20.0x4.0x1.0 mm) and six zirconia blocks (12.0x7.5x1.2 mm) were prepared and veneered with porcelain with different thickness: 1 mm, 2 mm, or 3 mm. The bars of each experimental group (n=10) were subjected to four-point flexural strength testing. In each ceramic block, a Vickers indentation was created under a load of 10 kgf for 10 seconds, for the propagation of cracks. Results: The results of flexural strength were evaluated by One-way ANOVA and Tukey's test, with a significance level of 5%. The factor “thickness of the porcelain” was statistically significant (p=0.001) and the l-mm group presented the highest values of flexural strength. The cracks were predominant among the bending specimens with 1 and 2 mm of porcelain, and catastrophic failures were found in 50% of 3-mm-thick porcelain. After the indentation of blocks, the most severe defects were observed in blocks with 3-mm-thick porcelain. Conclusion: The smallest (1 mm) thickness of porcelain on the zirconia infrastructure presented higher values of flexural strength. Better resistance to defect propagation was observed near the porcelain/ zirconia interface for all groups. Higher flexural strength was found for a thinner porcelain layer in a bilayered zirconia system. The damage caused by a Vickers indentation near and far the interface with the zirconia shows that the stress profiles are different. PMID:29069155

Boerhaave's syndrome in a patient with an upside down stomach: A case report.

PubMed

Saito, Shin; Hosoya, Yoshinori; Kurashina, Kentaro; Matsumoto, Shiro; Kanamaru, Rihito; Ui, Takashi; Haruta, Hidenori; Kitayama, Joji; Lefor, Alan K; Sata, Naohiro

2016-01-01

Spontaneous esophageal perforation, or Boerhaave's syndrome, is a life-threating condition which usually requires emergent surgery. An upside down stomach is defined as a gastric volvulus in a huge supradiaphragmatic sac. In general, this condition can result in ischemia and perforation of the stomach. This is the first report of a patient with Boerhaave's syndrome and an upside down stomach. A 79-year-old woman presented with sudden epigastric pain following hematemesis. Evaluation of the patient showed both an esophageal perforation and an upside down stomach. Surgical drainage and irrigation of the mediastinum and pleural cavities were undertaken emergently. Due to the concurrent gastric volvulus, a gastrostomy was placed to fix and decompress the stomach. The patient had an uneventful hospital course and was discharged. Boerhaave's syndrome is a rare but severe complication caused by excessive vomiting, due to a sudden elevation in intraluminal esophageal pressure resulting in esophageal perforation. Acute gastric volvulus can result in ischemia and perforation of the stomach, but has not previously been reported with esophageal perforation. The most likely mechanism associating an upside down stomach with Boerhaave's syndrome is acute gastric outlet obstruction resulting in vomiting, and subsequent esophageal perforation. Perforation of the esophagus as well as perforation of the stomach must be considered in patients with an upside down stomach although both upside down stomach and Boerhaave's syndrome are rare clinical entities. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Laparoscopic management of totally intra-thoracic stomach with chronic volvulus

PubMed Central

Toydemir, Toygar; Çipe, Gökhan; Karatepe, Oğuzhan; Yerdel, Mehmet Ali

2013-01-01

AIM: To evaluate the outcomes of patients who underwent laparoscopic repair of intra-thoracic gastric volvulus (IGV) and to assess the preoperative work-up. METHODS: A retrospective review of a prospectively collected database of patient medical records identified 14 patients who underwent a laparoscopic repair of IGV. The procedure included reduction of the stomach into the abdomen, total sac excision, reinforced hiatoplasty with mesh and construction of a partial fundoplication. All perioperative data, operative details and complications were recorded. All patients had at least 6 mo of follow-up. RESULTS: There were 4 male and 10 female patients. The mean age and the mean body mass index were 66 years and 28.7 kg/m2, respectively. All patients presented with epigastric discomfort and early satiety. There was no mortality, and none of the cases were converted to an open procedure. The mean operative time was 235 min, and the mean length of hospitalization was 2 d. There were no intraoperative complications. Four minor complications occurred in 3 patients including pleural effusion, subcutaneous emphysema, dysphagia and delayed gastric emptying. All minor complications resolved spontaneously without any intervention. During the mean follow-up of 29 mo, one patient had a radiological wrap herniation without volvulus. She remains symptom free with daily medication. CONCLUSION: The laparoscopic management of IGV is a safe but technically demanding procedure. The best outcomes can be achieved in centers with extensive experience in minimally invasive esophageal surgery. PMID:24124329

A case report and literature review of sigmoid volvulus in children.

PubMed

Chang, Po-Hsiung; Jeng, Chin-Ming; Chen, Der-Fang; Lin, Lung-Huang

2017-12-01

Sigmoid volvulus (SV) is an exceptionally rare but potentially life-threatening condition in children. Abdominal distention for 1 week. Sigmoid volvulus. We present a case of a 12-year-old boy with mechanical ileus who was finally confirmed to have SV with the combination of abdominal plain film, sonography, and computed tomography (CT) with the finding of mesenteric artery rotation. Because bowel obstruction was suspected, abdominal plain film, sonography, and CT were performed. The abdominal CT demonstrated whirlpool sign with torsion of the sigmoid vessels. In addition, lower gastrointestinal filling study showed that the contrast medium could only reach the upper descending colon. Therefore, he received laparotomy with mesosigmoidoplasty for detorsion of the sigmoid. The postoperative recovery was smooth under empirical antibiotic treatment with cefazolin. A follow-up lower gastrointestinal series on the seventh day of admission showed no obstruction compared with the previous series. He was finally discharged in a stable condition 8 days after admission. SV is a congenital anomaly and an uncommon diagnosis in children. Nevertheless, case series and case reports of SV are becoming more prevalent in the literature. Failure to recognize SV may result in life-threatening complications such as sigmoid gangrene/perforation, peritonitis, sepsis, and death. Thus, if the children have persistent and recurrent abdominal distention, abdominal pain, and vomiting, physicians should consider SV as a "do not miss diagnosis" in the differential diagnosis. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Entomologic considerations in the study of onchocerciasis transmission.

PubMed

Vargas, L; Díaz-Nájera, A

1980-01-01

The entomological resources utilized for a better understanding of Onchocerca volvulus transmission are discussed in this paper. Vector density, anthropohilia, gonotrophic cycyle, parous condition longevity and probability of survival in days after the infectious meal are assessed here in order to integrate an overall picture. The concept of vectorial capacity is developed stressing the quantitative aspects. Parasitism of the black-flies by filariae that are doubtfully identified as O. volvulus is also mentioned here.

Lethal mechanisms in gastric volvulus.

PubMed

Omond, Kimberley J; Byard, Roger W

2017-01-01

A 55-year-old wheelchair-bound woman with severe cerebral palsy was found at autopsy to have marked distention of the stomach due to a volvulus. The stomach was viable, and filled with air and fluid and had pushed the left dome of the diaphragm upwards causing marked compression of the left lung with a mediastinal shift to the right (including the heart). There was no evidence of gastric perforation, ischaemic necrosis or peritonitis. Removal of the organ block revealed marked kyphoscoliosis. Histology confirmed the viability of the stomach and biochemistry showed no dehydration. Death in cases of acute gastric volvulus usually occurs because of compromise of the gastric blood supply resulting in ischaemic necrosis with distention from swallowed air and fluid resulting in perforation with lethal peritonitis. Hypovolaemic shock may also occur. However, the current case demonstrates an alternative lethal mechanism, that of respiratory compromise due to marked thoracic organ compression.

A case report of percutaneous endoscopic gastrostomy left-side gastropexy to resolve a recurrent gastric dilatation in a dog previously treated with right-side gastropexy for gastric dilatation volvulus.

PubMed

Spinella, Giuseppe; Cinti, Filippo; Pietra, Marco; Capitani, Ombretta; Valentini, Simona

2014-12-01

A 6-year-old, large-breed, female dog was evaluated for gastric dilatation (GD). The dog was affected by GD volvulus, which had been surgically treated with gastric derotation and right incisional gastropexy. Recurrence of GD appeared 36 hours after surgery. The dilatation was immediately treated with an orogastric probe but still recurred 4 times. Therefore, a left-side gastropexy by percutaneous endoscopic gastrostomy (PEG) was performed to prevent intermittent GD. After PEG tube placement, the patient recovered rapidly without side effects. Several techniques of gastropexy have been described as a prophylactic method for gastric dilatation volvulus, but to the authors' knowledge, this is the first report of left-sided PEG gastropexy performed in a case of canine GD recurrence after an incisional right gastropexy. Copyright © 2015 Elsevier Inc. All rights reserved.

The effect of core material, veneering porcelain, and fabrication technique on the biaxial flexural strength and weibull analysis of selected dental ceramics.

PubMed

Lin, Wei-Shao; Ercoli, Carlo; Feng, Changyong; Morton, Dean

2012-07-01

The objective of this study was to compare the effect of veneering porcelain (monolithic or bilayer specimens) and core fabrication technique (heat-pressed or CAD/CAM) on the biaxial flexural strength and Weibull modulus of leucite-reinforced and lithium-disilicate glass ceramics. In addition, the effect of veneering technique (heat-pressed or powder/liquid layering) for zirconia ceramics on the biaxial flexural strength and Weibull modulus was studied. Five ceramic core materials (IPS Empress Esthetic, IPS Empress CAD, IPS e.max Press, IPS e.max CAD, IPS e.max ZirCAD) and three corresponding veneering porcelains (IPS Empress Esthetic Veneer, IPS e.max Ceram, IPS e.max ZirPress) were selected for this study. Each core material group contained three subgroups based on the core material thickness and the presence of corresponding veneering porcelain as follows: 1.5 mm core material only (subgroup 1.5C), 0.8 mm core material only (subgroup 0.8C), and 1.5 mm core/veneer group: 0.8 mm core with 0.7 mm corresponding veneering porcelain with a powder/liquid layering technique (subgroup 0.8C-0.7VL). The ZirCAD group had one additional 1.5 mm core/veneer subgroup with 0.7 mm heat-pressed veneering porcelain (subgroup 0.8C-0.7VP). The biaxial flexural strengths were compared for each subgroup (n = 10) according to ISO standard 6872:2008 with ANOVA and Tukey's post hoc multiple comparison test (p≤ 0.05). The reliability of strength was analyzed with the Weibull distribution. For all core materials, the 1.5 mm core/veneer subgroups (0.8C-0.7VL, 0.8C-0.7VP) had significantly lower mean biaxial flexural strengths (p < 0.0001) than the other two subgroups (subgroups 1.5C and 0.8C). For the ZirCAD group, the 0.8C-0.7VL subgroup had significantly lower flexural strength (p= 0.004) than subgroup 0.8C-0.7VP. Nonetheless, both veneered ZirCAD groups showed greater flexural strength than the monolithic Empress and e.max groups, regardless of core thickness and fabrication techniques. Comparing fabrication techniques, Empress Esthetic/CAD, e.max Press/CAD had similar biaxial flexural strength (p= 0.28 for Empress pair; p= 0.87 for e.max pair); however, e.max CAD/Press groups had significantly higher flexural strength (p < 0.0001) than Empress Esthetic/CAD groups. Monolithic core specimens presented with higher Weibull modulus with all selected core materials. For the ZirCAD group, although the bilayer 0.8C-0.7VL subgroup exhibited significantly lower flexural strength, it had highest Weibull modulus than the 0.8C-0.7VP subgroup. The present study suggests that veneering porcelain onto a ceramic core material diminishes the flexural strength and the reliability of the bilayer specimens. Leucite-reinforced glass-ceramic cores have lower flexural strength than lithium-disilicate ones, while fabrication techniques (heat-pressed or CAD/CAM) and specimen thicknesses do not affect the flexural strength of all glass ceramics. Compared with the heat-pressed veneering technique, the powder/liquid veneering technique exhibited lower flexural strength but increased reliability with a higher Weibull modulus for zirconia bilayer specimens. Zirconia-veneered ceramics exhibited greater flexural strength than monolithic leucite-reinforced and lithium-disilicate ceramics regardless of zirconia veneering techniques (heat-pressed or powder/liquid technique). © 2012 by the American College of Prosthodontists.

Genetic Selection of Low Fertile Onchocerca volvulus by Ivermectin Treatment

PubMed Central

Bourguinat, Catherine; Pion, Sébastien D. S.; Kamgno, Joseph; Gardon, Jacques

2007-01-01

Background Onchocerca volvulus is the causative agent of onchocerciasis, or “river blindness”. Ivermectin has been used for mass treatment of onchocerciasis for up to 18 years, and recently there have been reports of poor parasitological responses to the drug. Should ivermectin resistance be developing, it would have a genetic basis. We monitored genetic changes in parasites obtained from the same patients before use of ivermectin and following different levels of ivermectin exposure. Methods and Findings O. volvulus adult worms were obtained from 73 patients before exposure to ivermectin and in the same patients following three years of annual or three-monthly treatment at 150 µg/kg or 800 µg/kg. Genotype frequencies were determined in β-tubulin, a gene previously found to be linked to ivermectin selection and resistance in parasitic nematodes. Such frequencies were also determined in two other genes, heat shock protein 60 and acidic ribosomal protein, not known to be linked to ivermectin effects. In addition, we investigated the relationship between β-tubulin genotype and female parasite fertility. We found a significant selection for β-tubulin heterozygotes in female worms. There was no significant selection for the two other genes. Quarterly ivermectin treatment over three years reduced the frequency of the β-tubulin “aa” homozygotes from 68.6% to 25.6%, while the “ab” heterozygotes increased from 20.9% to 69.2% in the female parasites. The female worms that were homozygous at the β-tubulin locus were more fertile than the heterozygous female worms before treatment (67% versus 37%; p = 0.003) and twelve months after the last dose of ivermectin in the groups treated annually (60% versus 17%; p<0.001). Differences in fertility between heterozygous and homozygous worms were less apparent three months after the last treatment in the groups treated three-monthly. Conclusions The results indicate that ivermectin is causing genetic selection on O. volvulus. This genetic selection is associated with a lower reproductive rate in the female parasites. We hypothesize that this genetic selection indicates that a population of O. volvulus, which is more tolerant to ivermectin, is being selected. This selection could have implications for the development of ivermectin resistance in O. volvulus and for the ongoing onchocerciasis control programmes. PMID:17989786

Effect of Heat-Pressing Temperature and Holding Time on the Microstructure and Flexural Strength of Lithium Disilicate Glass-Ceramics

PubMed Central

Gao, Jing; Wang, Hui; Chen, Jihua

2015-01-01

The present study aimed to evaluate the influence of various heat-pressing procedures (different holding time and heat pressing temperature) on the microstructure and flexural strength of lithium disilicate glass ceramic. An experimental lithium silicate glass ceramic (ELDC) was prepared from the SiO2-Li2O-K2O-Al2O3-ZrO2-P2O5 system and heat-pressed following different procedures by varying temperature and holding time. The flexural strength was tested and microstructure was analyzed. The relationships between the microstructure, mechanical properties and heat-pressing procedures were discussed in-depth. Results verified the feasibility of the application of dental heat-pressing technique in processing the experimental lithium disilicate glass ceramic. Different heat-pressing procedures showed significant influence on microstructure and flexural strength. ELDC heat-pressed at 950℃ with holding time of 15 min achieved an almost pore-free microstructure and the highest flexural strength, which was suitable for dental restorative application. PMID:25985206

Factors associated with perioperative mortality in dogs with surgically managed gastric dilatation-volvulus: 137 cases (1988-1993).

PubMed

Brourman, J D; Schertel, E R; Allen, D A; Birchard, S J; DeHoff, W D

1996-06-01

To evaluate factors associated with perioperative mortality in dogs with gastric dilatation-volvulus and to determine the influence of treatment differences between university and private specialty practices on outcome. Retrospective analysis of medical records. 137 dogs with gastric dilatation-volvulus. Signalment; frequency of preoperative and postoperative treatments and complications; intraoperative findings; surgical technique; and hematologic, serum biochemical, and electrocardiographic results were recorded, evaluated for association with mortality, and compared between institutions. Mortality did not differ between institutions, and overall mortality was 18% (24/137). Surgical techniques differed between institutions, but were not associated with mortality. Gastric necrosis was associated with significantly higher mortality (46%; 13/28). When partial gastrectomy or splenectomy was performed, mortality (35 and 32% or 8/23 and 10/31, respectively) was significantly increased. Splenectomy was performed in 11 of 23 dogs requiring partial gastrectomy, and when both procedures were performed, mortality (55%; 6/11) was significantly increased. Preoperative cardiac arrhythmias were associated with significantly higher mortality (38%; 6/16). Mortality in dogs > 10 years old was not significantly greater than that in younger dogs. Patient management differences between practices did not seem to influence survival in dogs with surgically managed gastric dilatation-volvulus. Signalment, including age, did not influence mortality. Gastric necrosis, gastric resection, splenectomy, and preoperative cardiac arrhythmias were associated with mortality > 30%.

Canine gastric dilatation/volvulus syndrome in a veterinary critical care unit: 295 cases (1986-1992).

PubMed

Brockman, D J; Washabau, R J; Drobatz, K J

1995-08-15

Two hundred ninety-five case records were included in an analysis of dogs treated by a standardized protocol for gastric dilatation/volvulus syndrome between 1986 and 1992. A breed predisposition was demonstrated for Great Danes, German Shepherd Dogs, large mixed-breed dogs, and Standard Poodles. One hundred and ninety-three dogs had gastric dilatation and volvulus (GDV) confirmed at surgery, 66 had simple gastric dilatation (GD), and 36 others had gastric dilatation but volvulus could not be proved or disproved (GD +/- V). Among dogs with GDV, the fatality rate was 15% (29/193). Twenty-six (13.5%) dogs with GDV underwent partial gastrectomy, and 8 (31%) died or were subsequently euthanatized. In comparing the group of dogs with GDV that survived to those that died, there were no statistical differences in the age of dog, time between onset of clinical signs and admission, time from admission to surgery, or duration of anesthesia. Cardiac arrhythmias were detected in 40% (78/193) of the dogs with GDV. There also was no statistical correlation between development of a cardiac arrhythmia and outcome in dogs with GDV. The causes of death in dogs with GDV were multiple and varied; presumed gastric necrosis was a common reason for intraoperative euthanasia (11 dogs). Among dogs with GD or GD +/- V, the fatality rate was 0.9% (1/102).

Finite element analysis of end notch flexure specimen

NASA Technical Reports Server (NTRS)

Mall, S.; Kochhar, N. K.

1986-01-01

A finite element analysis of the end notch flexure specimen for mode II interlaminar fracture toughness measurement was conducted. The effect of friction between the crack faces and large deflection on the evaluation of G sub IIc from this specimen were investigated. Results of this study are presented in this paper.

Finite-element analysis of end-notch flexure specimens

NASA Technical Reports Server (NTRS)

Mall, S.; Kochhar, N. K.

1986-01-01

A finite-element analysis of the end-notch flexure specimen for Mode II interlaminar fracture toughness measurement was conducted. The effects of friction between the crack faces and large deflection on the evaluation of G(IIc) from this specimen were investigated. Results of this study are presented in this paper.

Design of a flexure mount for optics in dynamic and cryogenic environments

NASA Technical Reports Server (NTRS)

Pollard, Lloyd Wayne

1989-01-01

The design of a flexure mount for a mirror operating in a cryogenic environment is presented. This structure represents a design effort recently submitted to NASA Ames for the support of the primary mirror of the Space Infrared Telescope Facility (SIRTF). The support structure must passively accommodate the differential thermal contraction between the glass mirror and the aluminium structure of the telescope during cryogenic cooldown. Further, it must support the one meter diameter, 116 kilogram (258 pound) primary mirror during a severe launch to orbit without exceeding the micro-yield of the material anywhere in the flexure mount. Procedures used to establish the maximum allowable radial stiffness of the flexural mount, based on the finite element program NASTRAN and the optical program FRINGE, are discussed. Early design concepts were evaluated using a parametric design program, and the development of that program is presented. Dynamic loading analyses performed with NASTRAN are discussed. Methods of combining modal responses resulting from a displacement response spectrum analysis are discussed, and a combination scheme called MRSS, modified root of sum of squares, is presented. Model combination schemes using MRSS, SRSS, and ABS are compared to the results of the modal frequency response analysis performed with NASTRAN.

Co-endemicity of loiasis and onchocerciasis in rain forest communities in southwestern Nigeria.

PubMed

Ojurongbe, Olusola; Akindele, Akeem Abiodun; Adeleke, Monsuru Adebayo; Oyedeji, Matthew Oyebode; Adedokun, Samuel Adeyinka; Ojo, Josephine Folashade; Akinleye, Callistus Adewale; Bolaji, Oloyede Samuel; Adefioye, Olusegun Adelowo; Adeyeba, Oluwaseyi Adegboyega

2015-03-01

Loiasis is currently receiving attention as a disease of public health importance because of the possibility of increased risk of developing neurologic serious adverse event following mass ivermectin treatment against onchocerciasis in individual co-infected with Onchocerca volvulus and Loa loa. Rapid assessment procedure for loiasis (RAPLOA) was conducted in 12 communities covering the 3 senatorial districts of Osun State, Nigeria. A total of 960 people were interviewed for history of eye worm using the WHO guidelines for rapid assessment. The survey confirmed the presence of loiasis in all the 12 communities with 4 in Osun East/Ife south senatorial district being at high risk with a prevalence of over 40%. Based on the RAPLOA results, communities within Osun East/Ife south senatorial district were selected for microfilaraemic assessment of L. loa and O. volvulus. A total of 1115 and 1091 individuals were screened for L. loa and O. volvulus microfilaria worms respectively. 160 (14.3%) had L. loa microfilaria detected in their blood with 8 (5.0%) individuals having L. loa loads above 8000 mf/ml. 166 (15.2%) subjects had O. volvulus microfilaria (range 4-504 mf/ml) detected in their skin snip. 30 (2.69%) subjects were co-infected with both L. loa and O. volvulus. There was a significant variation in the prevalence (2.1% to 33.3%) of onchocerciasis in the communities studied (p = 0.001). Five (41.7%) of the studied communities had a prevalence that is equal to or greater than 20%. Low prevalence of onchocerciasis and loiasis co-infection in this study suggests that loiasis may not pose a serious epidemiological threat to the continuous distribution and sustainability of ivermectin for the treatment of onchocerciasis. Evaluation of the interruption of onchocerciasis transmissions in this region using all the indicators set forth by WHO is therefore suggested.

O-5S quantitative real-time PCR: a new diagnostic tool for laboratory confirmation of human onchocerciasis.

PubMed

Mekonnen, Solomon A; Beissner, Marcus; Saar, Malkin; Ali, Solomon; Zeynudin, Ahmed; Tesfaye, Kassahun; Adbaru, Mulatu G; Battke, Florian; Poppert, Sven; Hoelscher, Michael; Löscher, Thomas; Bretzel, Gisela; Herbinger, Karl-Heinz

2017-10-02

Onchocerciasis is a parasitic disease caused by the filarial nematode Onchocerca volvulus. In endemic areas, the diagnosis is commonly confirmed by microscopic examination of skin snip samples, though this technique is considered to have low sensitivity. The available melting-curve based quantitative real-time PCR (qPCR) using degenerated primers targeting the O-150 repeat of O. volvulus was considered insufficient for confirming the individual diagnosis, especially in elimination studies. This study aimed to improve detection of O. volvulus DNA in clinical samples through the development of a highly sensitive qPCR assay. A novel hydrolysis probe based qPCR assay was designed targeting the specific sequence of the O. volvulus O-5S rRNA gene. A total of 200 clinically suspected onchocerciasis cases were included from Goma district in South-west Ethiopia, from October 2012 through May 2013. Skin snip samples were collected and subjected to microscopy, O-150 qPCR, and the novel O-5S qPCR. Among the 200 individuals, 133 patients tested positive (positivity rate of 66.5%) and 67 negative by O-5S qPCR, 74 tested positive by microscopy (37.0%) and 78 tested positive by O-150 qPCR (39.0%). Among the 133 O-5S qPCR positive individuals, microscopy and O-150 qPCR detected 55.6 and 59.4% patients, respectively, implying a higher sensitivity of O-5S qPCR than microscopy and O-150 qPCR. None of the 67 individuals who tested negative by O-5S qPCR tested positive by microscopy or O-150 qPCR, implying 100% specificity of the newly designed O-5S qPCR assay. The novel O-5S qPCR assay is more sensitive than both microscopic examination and the existing O-150 qPCR for the detection of O. volvulus from skin snip samples. The newly designed assay is an important step towards appropriate individual diagnosis and control of onchocerciasis.

Elimination of onchocerciasis in Ecuador: findings of post-treatment surveillance.

PubMed

Guevara, Ángel; Lovato, Raquel; Proaño, Roberto; Rodriguez-Perez, Mario A; Unnasch, Thomas; Cooper, Philip J; Guderian, Ronald H

2018-04-24

The Esmeraldas focus of onchocerciasis in Ecuador expanded geographically during the 1980s and was associated with severe ocular and skin disease. Mass drug administration (MDA) with ivermectin started in 1991, initially once but later twice a year, in the principle endemic focus followed by all satellite foci. Treatment was stopped in 2009 when entomological assessments determined that transmission of Onchocerca volvulus had been interrupted. Three years after the cessation of ivermectin treatment in 2012, as defined by the WHO guidelines for onchocerciasis elimination, blackfly collections were done in four sentinel sites in former hyperendemic areas. The presence of infective larvae in local vectors, Simulium exiguum and Simulum quadrivittatum, was assessed by detection of O. volvulus DNA by PCR. Additional flies captured in four extra-sentinel sites located in former hyper- and mesoendemic dispersed isolated areas were also assessed. The results from 68,310 captured blackflies, 40,114 from four sentinel villages in the previously hyperendemic areas (Corriente Grande, El Tigre, San Miguel on Río Cayapas and Naranjal on Río Canandé) and 28,197 from extra-sentinel locations, were all negative for the presence of O. volvulus. These extra-sentinel sites (Hualpí on Río Hoja Blanca, Capulí on Río Onzole, La Ceiba on Río Tululví and Medianía on Río Verde) were included to provide additional evidence of the impact of MDA on the transmission of O. volvulus in isolated endemic areas. Our data indicate that transmission of O. volvulus has been stopped in all endemic areas in Ecuador, including all satellite foci outside the main focus. These findings indicate that a strategy of ivermectin distribution twice a year to over 85% of the treatment-eligible population was effective in eliminating the infection from Ecuador in a focus with a highly competent primary vector, S. exiguum, and where the infection rates were equal to or greater than observed in many onchocerciasis foci in Africa.

Small-bowel volvulus in late pregnancy due to internal hernia after laparoscopic Roux-en-Y gastric bypass.

PubMed

Naef, Markus; Mouton, Wolfgang G; Wagner, Hans E

2010-12-01

Internal hernias are a specific cause of acute abdominal pain and are a well-known complication after laparoscopic Roux-en-Y gastric bypass for morbid obesity. Although internal hernias are a rare cause of intestinal obstruction, they may evolve towards serious complications, such as extensive bowel ischemia and gangrene, with the need for bowel resection and sometimes for a challenging reconstruction of intestinal continuity. The antecolic position of the Roux limb is associated with a decrease in the incidence of small-bowel obstruction and internal hernias. The best prevention of the formation of these hernias is probably by closure of potential mesenteric defects at the initial operation with a non-absorbable running suture. We present a patient in late pregnancy with a small-bowel volvulus following laparoscopic Roux-en-Y gastric bypass for morbid obesity and discuss the available literature. For a favorable obstetric and neonatal outcome, it is crucial not to delay surgical exploration and an emergency operation usually is mandatory.

Review of gastric torsion in eight guinea pigs (Cavia porcellus).

PubMed

Nógrádi, Anna Linda; Cope, Iain; Balogh, Márton; Gál, János

2017-12-01

The authors present eight cases of gastric dilatation and volvulus (GDV) in guinea pigs from the Department and Clinic of Exotic Animal and Wildlife Medicine, University of Veterinary Medicine, Budapest, Hungary between 2012 and 2016. Seven animals were operated on and two survived. Gastric torsion has been noted in many mammalian species. Gastric volvulus has a high morbidity and high mortality rate with a guarded to poor prognosis in all of these species. How GDV develops is still not widely understood. Postmortem examinations, in both our cases and previously reported cases, have failed to reveal the exact causes of the gastric torsions. The aetiology of gastric torsion in guinea pigs is probably multifactorial. Feeding fewer meals per day, eating rapidly, decreased food particle size, exercise, stress after a meal, competition, age, and an aggressive or fearful temperament, are all likely and potential risk factors for GDV development in a similar fashion to dogs. Sex, breeding, dental diseases, anatomical abnormalities, pain and pregnancy may also be contributing factors.

Clinics in diagnostic imaging (171). Caecal volvulus with underlying intestinal malrotation.

PubMed

Ooi, Su Kai Gideon; Tan, Tien Jin; Ngu, James Chi Yong

2016-11-01

A 46-year-old Chinese woman with a history of cholecystectomy and appendicectomy presented to the emergency department with symptoms of intestinal obstruction. Physical examination revealed central abdominal tenderness but no clinical features of peritonism. Plain radiography of the abdomen revealed a grossly distended large bowel loop with the long axis extending from the right lower abdomen toward the epigastrium, and an intraluminal air-fluid level. These findings were suspicious for an acute caecal volvulus, which was confirmed on subsequent contrast-enhanced computed tomography (CT) of the abdomen and pelvis. CT demonstrated an abnormal positional relationship between the superior mesenteric vein and artery, indicative of an underlying intestinal malrotation. This case highlights the utility of preoperative imaging in establishing the diagnosis of an uncommon cause of bowel obstruction. It also shows the importance of recognising the characteristic imaging features early, so as to ensure appropriate and expedient management, thus reducing patient morbidity arising from complications. Copyright: © Singapore Medical Association.

Comments on new classification, treatment algorithm and prognosis-estimating systems for sigmoid volvulus and ileosigmoid knotting: necessity and utility.

PubMed

Aksungur, N; Korkut, E

2018-05-24

We read Atamanalp classification, treatment algorithm and prognosis-estimating systems for sigmoid volvulus (SV) and ileosigmoid knotting (ISK) in Colorectal Disease [1,2]. Our comments relate to necessity and utility of these new classification systems. Classification or staging systems are generally used in malignant or premalignant pathologies such as colorectal cancers [3] or polyps [4]. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

[Laparoscopic gastric sleeve in gastric volvulus secondary to diaphragmatic eventration in an adult patient].

PubMed

Gálvez-Valdovinos, Ramiro; Marín-Santillán, Ernesto; Funes-Rodríguez, Juan Francisco; López-Ambriz, Gustavo

2016-01-01

Acute gastric volvulus is a rare, but potentially life-threatening, cause of upper gastrointestinal obstruction. Male of 60 years old with severe epigastric pain and abdominal distension with haematemesis on two occasions. The patient was haemodynamically stable, with abdominal distension and palpable epigastric fullness. Hematic cytology showed: haemoglobin 8.2g/dl and haematocrit 27%. Abdominal X-ray showed an elevation of left diaphragm with a hugely dilated stomach. A nasogastric tube was inserted. Endoscopy was performed. There was no active bleeding, but it was impossible to reach the duodenum due to the stomach distortion. The upper gastrointestinal X-ray study showed the appearance of an inverted stomach in the chest and an organoaxial gastric torsion. The CT scans of thorax and abdomen showed a gastric ascent into the thoracic cavity. Laparoscopic surgery was performed, finding the left hemi-diaphragm elevated, and the stomach, splenic angle of the colon, the spleen and tail of the pancreas were also raised. A linear gastrectomy (gastric sleeve) was performed. The postoperative progress was satisfactory. Oral feeding was started 72 hours after surgery, and the patient was discharged, and has remained asymptomatic during the following by 8 years. Emergency physicians must maintain a high level of suspicion in patients that present with signs and symptoms suggesting upper digestive tract occlusion. The gastric sleeve is an excellent alternative to avoid recurrence of gastric volvulus. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

Subsurface mapping of the Ross Island flexural basin, southwest Antarctica

NASA Astrophysics Data System (ADS)

Wenman, Christopher P.

Ross Island is a post-Miocene (< 4.6 Ma) volcanic island located in the Ross Sea region of southwest Antarctica. This region of Antarctica borders the western edge of the West Antarctic Rift System, along the Transantarctic Mountain front. Marine and over-ice multi-channel seismic reflection surveys and borehole studies targeting the Ross Sea region over the last 30+ years have been used in this study to develop a seismic stratigraphic model of the development and evolution of the Ross Island flexural basin. Four key stratigraphic horizons were identified and mapped to fully capture the basin-fill, as well as strata lying above and below the flexural basin. From oldest to youngest these horizons are named RIB-m, RIM-g, RIM-b and RIB-r. Time structure, isochron and isochore maps were created for the horizons and the stratigraphic intervals they bound. The seismic stratigraphic record shows the Ross Island flexural moat formation post-dates the main tectonic subsidence phase within the Victoria Land Basin. The maps presented here are the first to fully illustrate the evolution of the Ross Island flexural basin. The maps highlight depositional patterns of two distinct periods of flexural subsidence and basin-filling superimposed on the older N-S trending Victoria Land Basin depocenter. Two units of flexural basin fill, Unit FFI between horizons RIM-g and RIM-b (the oldest flexural basin fill), and Unit FFII between horizons RIM-b and RIB-r (the youngest flexural basin fill) are associated with the two periods of flexural subsidence. Flexural moat subsidence and subsequent filling occurred episodically during periods of active volcanism on the island. Unit FFI is estimated to range from ca. 4 to 2 Ma, corresponding with formation of the Mt. Bird volcanic edifice on Ross Island. Unit FFII ranges in age from ca. 2 to 1 Ma, and is related to Mt. Terror, Mt. Erebus, and Hut Point Peninsula volcanism. The isochore maps suggest the depocenter of the flexural basin during both time intervals was located north of the island, instead of directly beneath the Ross Island topographic load. Factors contributing to the northerly location of the depocenter include i) volcanic loading by McMurdo Volcanic Group subsea volcanic features north of the island, ii) partial compensation of the main Ross Island load by low-density, partially molten rock beneath the island, iii) extensional faulting within the Terror Rift, and iv) seaward-thickening shelf sediments transported from the Ross Ice Shelf. The seismic data show that the onset of filling of the flexural moat around Ross Island coincided with the end of ice grounding events in the area. We infer that this was caused by flexural subsidence of the seafloor to accommodate the Ross Island load.

Flexural behaviour of RCC beams with externally bonded FRP

NASA Astrophysics Data System (ADS)

Vignesh, S. Arun; Sumathi, A.; Saravana Raja Mohan, K.

2017-07-01

The increasing use of carbon and glass fibre reinforced polymer (FRP) sheets for strengthening existing reinforced concrete beams has generated considerable interest in understanding the behavior of the FRP sheets when subjected to bending. The study on flexure includes various parameters like percentage of increase in strength of the member due to the externally bonded Fiber reinforced polymer, examining the crack patterns, reasons of debonding of the fibre from the structure, scaling, convenience of using the fibres, cost effectiveness etc. The present work aims to study experimentally about the reasons behind the failure due to flexure of an EB-FRP concrete beam by studying the various parameters. Deflection control may become as important as flexural strength for the design of FRPreinforced concrete structures. A numerical model is created using FEM software and the results are compared with that of the experiment.

The effects of stacking sequence and thermal cycling on the flexural properties of laminate composites of aluminium-epoxy/basalt-glass fibres

NASA Astrophysics Data System (ADS)

Abdollahi Azghan, Mehdi; Eslami-Farsani, Reza

2018-02-01

The current study aimed at investigating the effects of different stacking sequences and thermal cycling on the flexural properties of fibre metal laminates (FMLs). FMLs were composed of two aluminium alloy 2024-T3 sheets and epoxy polymer-matrix composites that have four layers of basalt and/or glass fibres with five different stacking sequences. For FML samples the thermal cycle time was about 6 min for temperature cycles from 25 °C to 115 °C. Flexural properties of samples evaluated after 55 thermal cycles and compared to non-exposed samples. Surface modification of aluminium performed by electrochemical treatment (anodizing) method and aluminium surfaces have been examined by scanning electron microscopy (SEM). Also, the flexural failure mechanisms investigated by the optical microscope study of fractured surfaces. SEM images indicated that the porosity of the aluminium surface increased after anodizing process. The findings of the present study showed that flexural modulus were maximum for basalt fibres based FML, minimum for glass fibres based FML while basalt/glass fibres based FML lies between them. Due to change in the failure mechanism of basalt/glass fibres based FMLs that have glass fibres at outer layer of the polymer composite, the flexural strength of this FML is lower than glass and basalt fibres based FML. After thermal cycling, due to the good thermal properties of basalt fibres, flexural properties of basalt fibres based FML structures decreased less than other composites.

Tensile and flexural strength of commercially pure titanium submitted to laser and tungsten inert gas welds.

PubMed

Atoui, Juliana Abdallah; Felipucci, Daniela Nair Borges; Pagnano, Valéria Oliveira; Orsi, Iara Augusta; Nóbilo, Mauro Antônio de Arruda; Bezzon, Osvaldo Luiz

2013-01-01

This study evaluated the tensile and flexural strength of tungsten inert gas (TIG) welds in specimens made of commercially pure titanium (CP Ti) compared with laser welds. Sixty cylindrical specimens (2 mm diameter x 55 mm thick) were randomly assigned to 3 groups for each test (n=10): no welding (control), TIG welding (10 V, 36 A, 8 s) and Nd:YAG laser welding (380 V, 8 ms). The specimens were radiographed and subjected to tensile and flexural strength tests at a crosshead speed of 1.0 mm/min using a load cell of 500 kgf applied on the welded interface or at the middle point of the non-welded specimens. Tensile strength data were analyzed by ANOVA and Tukey's test, and flexural strength data by the Kruskal-Wallis test (α=0.05). Non-welded specimens presented significantly higher tensile strength (control=605.84 ± 19.83) (p=0.015) and flexural strength (control=1908.75) (p=0.000) than TIG- and laser-welded ones. There were no significant differences (p>0.05) between the welding types for neither the tensile strength test (TIG=514.90 ± 37.76; laser=515.85 ± 62.07) nor the flexural strength test (TIG=1559.66; laser=1621.64). As far as tensile and flexural strengths are concerned, TIG was similar to laser and could be suitable to replace laser welding in implant-supported rehabilitations.

[Colon transverse volvulus; a case report].

PubMed

Ramírez-Wiella-Schwuchow, G; Villanueva-Sáenz, E; Bolaños-Badillo, L E; García-Hernández, L A

2009-01-01

Colon transverse volvulus is an uncommon pathology which is associate with alterations of the colonic motility, mental disorders and congenital anomalies of the fixation of the colon sistem. Up to 1994, 72 cases has been reported in world-wide literature. To report a case of colon transverse volvulus and the treatment. A female 46 years old who show intense abdominal pain 2 days of evolution. The physical exploration show important abdominal distension and pain in left inferior quadrant. The Rx of abdomen with gas absence in rectal descendent colon and ampula with level and important distension of proximal colon. Colonoscopic study with impossibility to advance endoscopy throw colon transverse by zone of stenosis, wasn't made a contrast study, underwent laparotomy of urgency, it was done right hemicolectomy and ileocoloanastomosis with good evolution and given of discharge fourth postsurgical day. This possibility is due to have in mind diagnoses, the treatment is surgical secondary to a high index of recidivate, nevertheless recommends the colonoscopy study accomplishment in order to discard obstructive injuries mainly cancer.

Transmission of Onchocerca volvulus by Simulium neavei in Mount Elgon Focus of Eastern Uganda Has Been Interrupted

PubMed Central

Katabarwa, Moses; Lakwo, Tom; Habomugisha, Peace; Agunyo, Stella; Byamukama, Edson; Oguttu, David; Ndyomugyenyi, Richard; Tukesiga, Ephraim; Ochieng, Galex Orukan; Abwaimo, Francis; Onapa, Ambrose; Lwamafa, Dennis W. K.; Walsh, Frank; Unnasch, Thomas R.; Richards, Frank O.

2014-01-01

The study determined that Simulium neavei-transmitted onchocerciasis in Mount Elgon onchocerciasis focus had been interrupted. Annual mass treatment with ivermectin changed to two times per year along with vector elimination in 2007. Then, baseline microfilaria (mf) prevalence data of 1994 in five sentinel communities were compared with follow-up data in 2005 and 2011. Blood spots from 3,051 children obtained in 2009 were analyzed for Onchocerca volvulus immunoglobulin G4 antibodies. Fresh water crab host captures and blackflies collected indicated their infestation with larval stages of S. neavei and presence or absence of the vector, respectively. Mf rates dropped from 62.2% to 0.5%, and 1 (0.03%) of 3,051 children was positive for O. volvulus antibodies. Crab infestation dropped from 41.9% in 2007 to 0%, and S. neavei biting reduced to zero. Both remained zero for the next 3 years, confirming interruption of onchocerciasis transmission, and interventions were halted. PMID:24686740

Adjustable bipod flexures for mounting mirrors in a space telescope.

PubMed

Kihm, Hagyong; Yang, Ho-Soon; Moon, Il Kweon; Yeon, Jeong-Heum; Lee, Seung-Hoon; Lee, Yun-Woo

2012-11-10

A new mirror mounting technique applicable to the primary mirror in a space telescope is presented. This mounting technique replaces conventional bipod flexures with flexures having mechanical shims so that adjustments can be made to counter the effects of gravitational distortion of the mirror surface while being tested in the horizontal position. Astigmatic aberration due to the gravitational changes is effectively reduced by adjusting the shim thickness, and the relation between the astigmatism and the shim thickness is investigated. We tested the mirror interferometrically at the center of curvature using a null lens. Then we repeated the test after rotating the mirror about its optical axis by 180° in the horizontal setup, and searched for the minimum system error. With the proposed flexure mount, the gravitational stress at the adhesive coupling between the mirror and the mount is reduced by half that of a conventional bipod flexure for better mechanical safety under launch loads. Analytical results using finite element methods are compared with experimental results from the optical interferometer. Vibration tests verified the mechanical safety and optical stability, and qualified their use in space applications.

Effect of in vitro aging on the flexural strength and probability to fracture of Y-TZP zirconia ceramics for all-ceramic restorations.

PubMed

Siarampi, Eleni; Kontonasaki, Eleana; Andrikopoulos, Konstantinos S; Kantiranis, Nikolaos; Voyiatzis, George A; Zorba, Triantafillia; Paraskevopoulos, Konstantinos M; Koidis, Petros

2014-12-01

Dental zirconia restorations should present long-term clinical survival and be in service within the oral environment for many years. However, low temperature degradation could affect their mechanical properties and survival. The aim of this study was to investigate the effect of in vitro aging on the flexural strength of yttrium-stabilized (Y-TZP) zirconia ceramics for ceramic restorations. One hundred twenty bar-shaped specimens were prepared from two ceramics (ZENO Zr (WI) and IPS e.max(®) ZirCAD (IV)), and loaded until fracture according to ISO 6872. The specimens from each ceramic (nx=60) were divided in three groups (control, aged for 5h, aged for 10h). One-way ANOVA was used to assess statistically significant differences among flexural strength values (P<0.05). The variability of the flexural strength values was analyzed using the two-parameter Weibull distribution function, which was applied for the estimation of Weibull modulus (m) and characteristic strength (σ0). The crystalline phase polymorphs of the materials (tetragonal, t, and monoclinic, m, zirconia) were investigated by X-ray diffraction (XRD) analysis, Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. A slight increase of the flexural strength after 5h, and a decrease after 10h of aging, was recorded for both ceramics, however statistically significant was for the WI group (P<0.05). Both ceramics presented a t→m phase transformation, with the m-phase increasing from 4 to 5% at 5h to around 15% after 10h. The significant reduction of the flexural strength after 10h of in vitro aging, suggests high fracture probability for one of the zirconia ceramics tested. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Design of the GOES Telescope secondary mirror mounting

NASA Technical Reports Server (NTRS)

Hookman, Robert A.

1989-01-01

The GOES Telescope utilizes a flexure mounting system for the secondary mirror to minimize thermally induced distortions of the secondary mirror. The detailed design is presented along with a discussion of the microradian pointing requirements and how they were achieved. The methodology used to dynamically tune the flexure/secondary mirror assembly to minimize structural interactions will also be discussed.

Flexural creep of structural flakeboards under cyclic humidity

Treesearch

M.C. Yeh; R.C. Tang; Chung-Yun Hse

1990-01-01

Flexural creep behavior of randomly oriented structural flakeboards under cyclic humidity is presented. Specimens fabricated with 5 and 7 percent phenol-formaldehyde resin were subjected to constant concentrated load in bending under slow and fast cyclic relative humidity (RH) between 65 and 95 percent for 100 days. The temperature was set at a constant 75°F through...

Monolithic superelastic rods with variable flexural stiffness for spinal fusion: modeling of the processing-properties relationship.

PubMed

Facchinello, Yann; Brailovski, Vladimir; Petit, Yvan; Mac-Thiong, Jean-Marc

2014-11-01

The concept of a monolithic Ti-Ni spinal rod with variable flexural stiffness is proposed to reduce the risks associated with spinal fusion. The variable stiffness is conferred to the rod using the Joule-heating local annealing technique. The annealing temperature and the mechanical properties' distributions resulted from this thermal treatment are numerically modeled and experimentally measured. To illustrate the possible applications of such a modeling approach, two case studies are presented: (a) optimization of the Joule-heating strategy to reduce annealing time, and (b) modulation of the rod's overall flexural stiffness using partial annealing. A numerical model of a human spine coupled with the model of the variable flexural stiffness spinal rod developed in this work can ultimately be used to maximize the stabilization capability of spinal instrumentation, while simultaneously decreasing the risks associated with spinal fusion. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

Construction, wind tunnel testing and data analysis for a 1/5 scale ultra-light wing model

NASA Technical Reports Server (NTRS)

James, Michael D.; Smith, Howard W.

1993-01-01

This report documents the construction, wind tunnel testing, and data analysis of a 1/5 scale ultra-light wing section. Wind tunnel testing provided accurate and meaningful lift, drag, and pitching moment data. This data was processed and graphically presented as follows: C(sub L) vs. gamma; C(sub D) vs. gamma; C(sub M) vs. gamma; and C(sub L) vs. C(sub D). The wing fabric flexure was found to be significant and its possible effects on aerodynamic data was discussed. The fabric flexure is directly related to wing angle of attack and airspeed. Different wing section shapes created by fabric flexure are presented with explanations of the types of pressures that act upon the wing surface. This report provides conclusive aerodynamic data for ultra-light wings.

Influence of Grid Reinforcement Placed In Masonry Bed Joints on Its Flexural Strength

NASA Astrophysics Data System (ADS)

Piekarczyk, Adam

2017-10-01

The paper presents the test results of the flexural strength of masonry when plane of failure is perpendicular to the bed joints. Comparison tests of unreinforced specimens and specimens reinforced with steel wire, glass and basalt fibre grids applied in masonry bed joints showed the higher flexural strength and crack resistance of masonry reinforced in this manner and so loaded. Reinforced masonry exposed plastic character after cracking allow for large horizontal displacements and transfer the considerable loads perpendicular to their surface. The strengthening of masonry was observed in most tests of reinforced specimens leading to occurrence of the maximum load in after cracking phase.

Flexural creep behaviour of jute polypropylene composites

NASA Astrophysics Data System (ADS)

Chandekar, Harichandra; Chaudhari, Vikas

2016-09-01

Present study is about the flexural creep behaviour of jute fabric reinforced polypropylene (Jute-PP) composites. The PP sheet and alkali treated jute fabric is stacked alternately and hot pressed in compression molding machine to get Jute-PP composite laminate. The flexural creep study is carried out on dynamic mechanical analyzer. The creep behaviour of the composite is modeled using four-parameter Burgers model. Short-term accelerated creep testing is conducted which is later used to predict long term creep behaviour. The feasibility of the construction of a master curve using the time-temperature superposition (TTS) principle to predict long term creep behavior of unreinforced PP and Jute-PP composite is investigated.

Prediction of properties of intraply hybrid composites

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Sinclair, J. H.

1979-01-01

Equations based on the mixtures rule are presented for predicting the physical, thermal, hygral, and mechanical properties of unidirectional intraply hybrid composites (UIHC) from the corresponding properties of their constituent composites. Bounds were derived for uniaxial longitudinal strengths, tension, compression, and flexure of UIHC. The equations predict shear and flexural properties which agree with experimental data from UIHC. Use of these equations in a composites mechanics computer code predicted flexural moduli which agree with experimental data from various intraply hybrid angleplied laminates (IHAL). It is indicated, briefly, how these equations can be used in conjunction with composite mechanics and structural analysis during the analysis/design process.

Elastic thickness determination based on Vening Meinesz-Moritz and flexural theories of isostasy

NASA Astrophysics Data System (ADS)

Eshagh, Mehdi

2018-06-01

Elastic thickness (Te) is one of mechanical properties of the Earth's lithosphere. The lithosphere is assumed to be a thin elastic shell, which is bended under the topographic, bathymetric and sediment loads on. The flexure of this elastic shell depends on its thickness or Te. Those shells having larger Te flex less. In this paper, a forward computational method is presented based on the Vening Meinesz-Moritz (VMM) and flexural theories of isostasy. Two Moho flexure models are determined using these theories, considering effects of surface and subsurface loads. Different values are selected for Te in the flexural method to see by which one, the closest Moho flexure to that of the VMM is achieved. The effects of topographic/bathymetric, sediments and crustal crystalline masses, and laterally variable upper mantle density, Young's modulus and Poisson's ratio are considered in whole computational process. Our mathematical derivations are based on spherical harmonics, which can be used to estimate Te at any single point, meaning that there is no edge effect in the method. However, the Te map needs to be filtered to remove noise at some points. A median filter with a window size of 5° × 5° and overlap of 4° works well for this purpose. The method is applied to estimate Te over South America using the data of CRUST1.0 and a global gravity model.

Synthesis of Zinc Oxide Nanoparticles and Their Effect on the Compressive Strength and Setting Time of Self-Compacted Concrete Paste as Cementitious Composites

PubMed Central

Arefi, Mohammad Reza; Rezaei-Zarchi, Saeed

2012-01-01

In the present study, the mechanical properties of self-compacting concrete were investigated after the addition of different amounts of ZnO nanoparticles. The zinc oxide nanoparticles, with an average particle size of about 30 nm, were synthesized and their properties studied with the help of a scanning electron microscope (SEM) and X-ray diffraction. The prepared nanoparticles were partially added to self-compacting concrete at different concentrations (0.05, 0.1, 0.2, 0.5 and 1.0%), and the mechanical (flexural and split tensile) strength of the specimens measured after 7, 14, 21 and 28 days, respectively. The present results have shown that the ZnO nanoparticles were able to improve the flexural strength of self-compacting concrete. The increased ZnO content of more than 0.2% could increase the flexural strength, and the maximum flexural and split tensile strength was observed after the addition of 0.5% nanoparticles. Finally, ZnO nanoparticles could improve the pore structure of the self-compacted concrete and shift the distributed pores to harmless and less-harmful pores, while increasing mechanical strength. PMID:22605981

Synthesis of zinc oxide nanoparticles and their effect on the compressive strength and setting time of self-compacted concrete paste as cementitious composites.

PubMed

Arefi, Mohammad Reza; Rezaei-Zarchi, Saeed

2012-01-01

In the present study, the mechanical properties of self-compacting concrete were investigated after the addition of different amounts of ZnO nanoparticles. The zinc oxide nanoparticles, with an average particle size of about 30 nm, were synthesized and their properties studied with the help of a scanning electron microscope (SEM) and X-ray diffraction. The prepared nanoparticles were partially added to self-compacting concrete at different concentrations (0.05, 0.1, 0.2, 0.5 and 1.0%), and the mechanical (flexural and split tensile) strength of the specimens measured after 7, 14, 21 and 28 days, respectively. The present results have shown that the ZnO nanoparticles were able to improve the flexural strength of self-compacting concrete. The increased ZnO content of more than 0.2% could increase the flexural strength, and the maximum flexural and split tensile strength was observed after the addition of 0.5% nanoparticles. Finally, ZnO nanoparticles could improve the pore structure of the self-compacted concrete and shift the distributed pores to harmless and less-harmful pores, while increasing mechanical strength.

The vectoral role of several blackfly species (Diptera: Simuliidae) in relation to human onchocerciasis in the Sierra Parima and Upper Orinoco regions of Venezuela.

PubMed

Basáñez, M G; Yarzábal, L; Takaoka, H; Suzuki, H; Noda, S; Tada, I

1988-12-01

Experimental and natural infections with Onchocerca volvulus were studied in several anthropophilic blackfly species present in the endemic area of the Upper Orinoco region of Venezuela. When fed on four different Yanomami volunteers in the Sierra Parima, the total infection rate was 31.4% for Simulium guianense in comparison with 7.5% for S. limbatum. The proportion of ingested microfilariae that entered the thorax during the first 24 hours and completed development to the infective stage was also much lower in the latter than in the former species. There was no larval development of O. volvulus in S. antillarum, but one female harboured in its head six infective larvae of a zoonotic filaria. When S. oyapokense s.l. was fed on an infected volunteer in the Upper Orinoco most flies ingested few microfilariae, and further development reached only the L1 stage. Natural infection and infectivity rates for S. guianense in two localities of the Sierra Parima were 0.2-4.0% and 1.3-10.2%, respectively, more than 50% of the L3 larvae being in the head. The corresponding data for S. oyapockense s.l. in the Upper Orinoco were 0.1-0.5%, although the only L3 larva found did not correspond to O. volvulus. It is suggested that S. guianense is the main vector of onchocerciasis in the Sierra Parima and that S. limbatum could play a secondary role. Simulium oyapockense s.l. replaces them in the Upper Orinoco and may maintain a degree of transmission, but its epidemiological importance remains to be assessed.

Statistical Analysis of Compressive and Flexural Test Results on the Sustainable Adobe Reinforced with Steel Wire Mesh

NASA Astrophysics Data System (ADS)

Jokhio, Gul A.; Syed Mohsin, Sharifah M.; Gul, Yasmeen

2018-04-01

It has been established that Adobe provides, in addition to being sustainable and economic, a better indoor air quality without spending extensive amounts of energy as opposed to the modern synthetic materials. The material, however, suffers from weak structural behaviour when subjected to adverse loading conditions. A wide range of mechanical properties has been reported in literature owing to lack of research and standardization. The present paper presents the statistical analysis of the results that were obtained through compressive and flexural tests on Adobe samples. Adobe specimens with and without wire mesh reinforcement were tested and the results were reported. The statistical analysis of these results presents an interesting read. It has been found that the compressive strength of adobe increases by about 43% after adding a single layer of wire mesh reinforcement. This increase is statistically significant. The flexural response of Adobe has also shown improvement with the addition of wire mesh reinforcement, however, the statistical significance of the same cannot be established.

Extracts of Euphorbia hirta Linn. (Euphorbiaceae) and Rauvolfia vomitoria Afzel (Apocynaceae) demonstrate activities against Onchocerca volvulus microfilariae in vitro.

PubMed

Attah, Simon K; Ayeh-Kumi, Patrick F; Sittie, Archibald A; Oppong, Isaac V; Nyarko, Alexander K

2013-03-18

Onchocerciasis transmitted by Onchocerca volvulus is the second major cause of blindness in the world and it impacts negatively on the socio-economic development of the communities affected. Currently, ivermectin, a microfilaricidal drug is the only drug recommended for treating this disease. There have been speculations, of late, concerning O. volvulus resistance to ivermectin. Owing to this, it has become imperative to search for new drugs. World-wide, ethnomedicines including extracts of Euphorbia hirta and Rauvolfia vomitoria are used for treating various diseases, both infectious and non-infectious. In this study extracts of the two plants were evaluated in vitro in order to determine their effect against O. volvulus microfilariae. The toxicity of the E. hirta extracts on monkey kidney cell (LLCMK2) lines was also determined. The investigations showed that extracts of both plants immobilised microfilariae at different levels in vitro and, therefore, possess antifilarial properties. It was found that all the E. hirta extracts with the exception of the hexane extracts were more effective than those of R. vomitoria. Among the extracts of E. hirta the ethyl acetate fraction was most effective, and comparable to that of dimethanesulphonate salt but higher than that of Melarsoprol (Mel B). However, the crude ethanolic extract of E. hirta was found to be the least toxic to the LLCMK2 compared to the fractionated forms. Extracts from both plants possess antifilarial properties; however, the crude extract of E. hirta was found to be least toxic to LLCMK2.

Extracts of Euphorbia hirta Linn. (Euphorbiaceae) and Rauvolfia vomitoria Afzel (Apocynaceae) demonstrate activities against Onchocerca volvulus Microfilariae in vitro

PubMed Central

2013-01-01

Background Onchocerciasis transmitted by Onchocerca volvulus is the second major cause of blindness in the world and it impacts negatively on the socio-economic development of the communities affected. Currently, ivermectin, a microfilaricidal drug is the only drug recommended for treating this disease. There have been speculations, of late, concerning O. volvulus resistance to ivermectin. Owing to this, it has become imperative to search for new drugs. World-wide, ethnomedicines including extracts of Euphorbia hirta and Rauvolfia vomitoria are used for treating various diseases, both infectious and non-infectious. Method In this study extracts of the two plants were evaluated in vitro in order to determine their effect against O. volvulus microfilariae. The toxicity of the E. hirta extracts on monkey kidney cell (LLCMK2) lines was also determined. Results The investigations showed that extracts of both plants immobilised microfilariae at different levels in vitro and, therefore, possess antifilarial properties. It was found that all the E. hirta extracts with the exception of the hexane extracts were more effective than those of R. vomitoria. Among the extracts of E. hirta the ethyl acetate fraction was most effective, and comparable to that of dimethanesulphonate salt but higher than that of Melarsoprol (Mel B). However, the crude ethanolic extract of E. hirta was found to be the least toxic to the LLCMK2 compared to the fractionated forms. Conclusions Extracts from both plants possess antifilarial properties; however, the crude extract of E. hirta was found to be least toxic to LLCMK2. PMID:23506674

Occlusal force, electromyographic activity of masticatory muscles and mandibular flexure of subjects with different facial types

PubMed Central

CUSTODIO, William; GOMES, Simone Guimarães Farias; FAOT, Fernanda; GARCIA, Renata Cunha Matheus Rodrigues; DEL BEL CURY, Altair Antoninha

2011-01-01

Objective The aim of this study was to evaluate whether vertical facial patterns influence maximal occlusal force (MOF), masticatory muscle electromyographic (EMG) activity, and medial mandibular flexure (MMF). Material and Methods Seventy-eight dentate subjects were divided into 3 groups by Ricketts's analysis: brachyfacial, mesofacial and dolychofacial. Maximum occlusal force in the molar region was bilaterally measured with a force transducer. The electromyographic activities of the masseter and anterior temporal muscles were recorded during maximal voluntary clenching. Medial mandibular flexure was calculated by subtracting the intermolar distance of maximum opening or protrusion from the distance in the rest position. The data were analyzed using ANOVA followed by Tukey's HSD test. The significance level was set at 5%. Results Data on maximum occlusal force showed that shorter faces had higher occlusal forces (P<0.0001). Brachyfacial subjects presented higher levels of masseter electromyographic activity and medial mandibular flexure, followed by the mesofacial and dolychofacial groups. Additionally, dolychofacial subjects showed significantly lower electromyographic temporalis activities (P<0.05). Conclusion Within the limitations of the study, it may be concluded that maximum occlusal force, masticatory muscle activity and medial mandibular flexure were influenced by the vertical facial pattern. PMID:21655772

Stage-Specific Transcriptome and Proteome Analyses of the Filarial Parasite Onchocerca volvulus and Its Wolbachia Endosymbiont

PubMed Central

Bennuru, Sasisekhar; Cotton, James A.; Ribeiro, Jose M. C.; Grote, Alexandra; Harsha, Bhavana; Holroyd, Nancy; Mhashilkar, Amruta; Molina, Douglas M.; Randall, Arlo Z.; Shandling, Adam D.; Unnasch, Thomas R.; Ghedin, Elodie; Berriman, Matthew

2016-01-01

ABSTRACT Onchocerciasis (river blindness) is a neglected tropical disease that has been successfully targeted by mass drug treatment programs in the Americas and small parts of Africa. Achieving the long-term goal of elimination of onchocerciasis, however, requires additional tools, including drugs, vaccines, and biomarkers of infection. Here, we describe the transcriptome and proteome profiles of the major vector and the human host stages (L1, L2, L3, molting L3, L4, adult male, and adult female) of Onchocerca volvulus along with the proteome of each parasitic stage and of its Wolbachia endosymbiont (wOv). In so doing, we have identified stage-specific pathways important to the parasite’s adaptation to its human host during its early development. Further, we generated a protein array that, when screened with well-characterized human samples, identified novel diagnostic biomarkers of O. volvulus infection and new potential vaccine candidates. This immunomic approach not only demonstrates the power of this postgenomic discovery platform but also provides additional tools for onchocerciasis control programs. PMID:27881553

Climatic conditions as a risk factor in canine gastric dilatation-volvulus.

PubMed

Dennler, R; Koch, D; Hassig, M; Howard, J; Montavon, P M

2005-01-01

Canine acute gastric dilatation-volvulus (GDV) is a life-threatening condition of multifactorial origin. The risk of developing GDV is influenced by a variety of factors, including breed, age, gender, temperament, diet and management. A relationship between seasonal variations and the frequency of GDV has been previously documented although no association was found with any specific climatic event. Variables in weather conditions within a defined geographic region were investigated in a retrospective study of 287 client-owned dogs diagnosed with GDV between 1992 and 1999. Monthly incidences were evaluated and differences in atmospheric temperature, humidity and pressure between days in which GDV cases were observed and days in which no case was presented were examined. Although temperature was significantly associated with the occurrence of GDV, the difference in temperatures between days with and days without GDV cases was so small that it is unlikely to be of clinical relevance. Moreover, no significant association was found between GDV occurrence and atmospheric pressure or humidity, and a seasonal variation in GDV incidence was not observed.

[Intestinal volvulus caused by the ingestion of magnet balls: unexpected risk in children].

PubMed

Kubačková, D; Nosek, J; Třeška, V; Vacek, V; Pizingerová, K

2015-05-01

The occurrence of swallowed foreign bodies in the digestive system is a common problem in children with the highest incidence in children aged six months to five years. Most swallowed objects leave the human body per vias naturales while 10-20% of swallowed foreign bodies need to be removed with an endoscope. Serious and life-threatening situations are caused by the ingestion of foreign bodies in about 1% of all cases. The authors present a case of a two-year-old girl diagnosed with acute abdomen for which she was operated on. A small bowel volvulus and several intestinal fistulas were found intraoperatively. The cause of this finding was the ingestion of magnetic balls and a swallowed metal body drawn to them by magnetic force. If more than one magnetic body is ingested, it is necessary to admit the patient to hospital and to remove these foreign bodies using an endoscope. The position of the magnets which is not changing in a location inaccessible for an endoscope during 2448 hours is an indication for urgent operation.

Human infection patterns and heterogeneous exposure in river blindness

PubMed Central

Filipe, João A. N.; Boussinesq, Michel; Renz, Alfons; Collins, Richard C.; Vivas-Martinez, Sarai; Grillet, María-Eugenia; Little, Mark P.; Basáñez, María-Gloria

2005-01-01

Here we analyze patterns of human infection with Onchocerca volvulus (the cause of river blindness) in different continents and ecologies. In contrast with some geohelminths and schistosome parasites whose worm burdens typically exhibit a humped pattern with host age, patterns of O. volvulus infection vary markedly with locality. To test the hypothesis that such differences are partly due to heterogeneity in exposure to vector bites, we develop an age- and sex-structured model for intensity of infection, with parasite regulation within humans and vectors. The model is fitted to microfilarial data from savannah villages of northern Cameroon, coffee fincas of central Guatemala, and forest-dwelling communities of southern Venezuela that were recorded before introducing ivermectin treatment. Estimates of transmission and infection loads are compared with entomological and epidemiological field data. Host age- and sex-heterogeneous exposure largely explains locale-specific infection patterns in onchocerciasis (whereas acquired protective immunity has been invoked for other helminth infections). The basic reproductive number,R0, ranges from 5 to 8, which is slightly above estimates for other helminth parasites but well below previously presented values. PMID:16217028

Gallbladder volvulus with segmental right liver lobe hypoplasia/atrophy: a preoperative diagnostic dilemma.

PubMed

Musthafa, Shameel; Aftab, Zia; Ali, Syed Muhammad; Khanna, Maneesh

2018-06-08

Gallbladder volvulus (GBV) due to rotation of the gall bladder (GB) around its own mesentery is a rare surgical emergency and often identified intraoperatively. Typically, cholecystitis is the initial clinical diagnosis, but a high index of suspicion on imaging can alert the physician for the possibility of GBV requiring urgent surgical intervention. We describe a case of a young female patient with hypoplasia/atrophy of the posterior segment of the right liver lobe and a GB with no hepatic attachments but only mesenteric pedicle. She presented with first episode of sudden-onset, severe right subcostal pain. The ultrasonogram and magnetic resonance cholangiopancreatogram findings were suggestive of GBV. She underwent laparoscopic exploration that confirmed GBV of a free-floating GB with a thrombosed cystic artery. The GB was detorted, and cholecystectomy was performed. She had an uneventful postoperative course and was discharged with no complications. Histopathological examination showed intramural haematoma of the GB with wall necrosis. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

The prevalence, intensity and clinical manifestations of Onchocerca volvulus infection in Toro local government area of Bauchi State, Nigeria.

PubMed

Anosike, J C; Celestine; Onwuliri, O E; Onwuliri, V A

2001-07-01

Between January and October 1994, a study of the prevalence, intensity and clinical manifestations of onchocerciasis in nine communities of Toro local government area of Bauchi State, Nigeria was undertaken using the skin-snip method. Of the 1117 inhabitants examined, 188 (16.8%) were positive for microfilariae of Onchocerca volvulus. The prevalence of onchocerciasis was significantly higher (P < 0.05) among males than females, in subjects 21 years of age and above than in those in the first two decades of life, in nomads, farmers, hunters and fishermen than smiths and traders. Intensity of infection was light, not exceeding a geometric mean of 5.3 microfilaria per 2 mm skin bite. Preponderance of positive cases below 20 years presented no chronic signs. Conversely, persons above 20 years had higher microfilaria counts which coincides with the period when most clinical signs manifest. Microfilarial-rate and -density in relation to age were closely associated (r = 0.75, P < 0.001). The need for a sustained mass distribution of Mectizan in these communities is highlighted.

Effect of the addition of silanated silica on the mechanical properties of microwave heat-cured acrylic resin.

PubMed

da Silva, Lucas H; Feitosa, Sabrina A; Valera, Marcia C; de Araujo, Maria A M; Tango, Rubens N

2012-06-01

The purpose of this study was to evaluate the flexural strength and Vickers hardness of a microwave energy heat-cured acrylic resin by adding different concentrations of silane surface-treated nanoparticle silica. Acrylic resin specimens with dimensions of 65 × 10 × 2.5 mm were formed and divided into five experimental groups (n = 10) according to the silica concentration added to the acrylic resin mass (weight %) prior to polymerisation : G1, without silica; G2, 0.1% silica; G3, 0.5% silica; G4, 1.0% silica; and G5, 5.0% silica. The specimens were submitted to a three-point flexural strength test and to the Vickers hardness test (HVN). The data obtained were statistically analysed by anova and the Tukey test (α = 0.05). Regarding flexural strength, G5 differed from the other experimental groups (G1, G2, G3 and G4) presenting the lowest mean, while G4 presented a significantly higher mean, with the exception of group G3. Regarding Vickers hardness, a decrease in values was observed, in which G1 presented the highest hardness compared with the other experimental groups. Incorporating surface-treated silica resulted in direct benefits in the flexural strength of the acrylic resin activated by microwave energy; however, similar results were not achieved for hardness. © 2012 The Gerodontology Society and John Wiley & Sons A/S.

Gastric Necrosis due to Acute Massive Gastric Dilatation.

PubMed

Aydin, Ibrahim; Pergel, Ahmet; Yucel, Ahmet Fikret; Sahin, Dursun Ali; Ozer, Ender

2013-01-01

Gastric necrosis due to acute massive gastric dilatation is relatively rare. Vascular reasons, herniation, volvulus, acute gastric dilatation, anorexia, and bulimia nervosa play a role in the etiology of the disease. Early diagnosis and treatment are highly important as the associated morbidity and mortality rates are high. In this case report, we present a case of gastric necrosis due to acute gastric dilatation accompanied with the relevant literature.

Gastric Necrosis due to Acute Massive Gastric Dilatation

PubMed Central

Pergel, Ahmet; Yucel, Ahmet Fikret; Sahin, Dursun Ali; Ozer, Ender

2013-01-01

Gastric necrosis due to acute massive gastric dilatation is relatively rare. Vascular reasons, herniation, volvulus, acute gastric dilatation, anorexia, and bulimia nervosa play a role in the etiology of the disease. Early diagnosis and treatment are highly important as the associated morbidity and mortality rates are high. In this case report, we present a case of gastric necrosis due to acute gastric dilatation accompanied with the relevant literature. PMID:23983714

Association between previous splenectomy and gastric dilatation-volvulus in dogs: 453 cases (2004-2009).

PubMed

Sartor, Angela J; Bentley, Adrienne M; Brown, Dorothy C

2013-05-15

To evaluate the association between previous splenectomy and gastric dilatation-volvulus (GDV) in dogs. Multi-institutional retrospective case-control study. Animals-151 dogs treated surgically for GDV and 302 control dogs with no history of GDV. Computerized records of dogs evaluated via exploratory laparotomy or abdominal ultrasonography were searched, and dogs with GDV and dogs without GDV (control dogs) were identified. Two control dogs were matched with respect to age, body weight, sex, neuter status, and breed to each dog with GDV. Data were collected on the presence or absence of the spleen for both dogs with GDV and control dogs. Conditional logistic regression analysis was used to investigate the association of previous splenectomy with GDV. 6 (4%) dogs in the GDV group and 3 (1%) dogs in the control group had a history of previous splenectomy. The odds of GDV in dogs with a history of previous splenectomy in this population of dogs were 5.3 times those of dogs without a history of previous splenectomy (95% confidence interval, 1.1 to 26.8). For the patients in the present study, there was an increased odds of GDV in dogs with a history of splenectomy. Prophylactic gastropexy may be considered in dogs undergoing a splenectomy, particularly if other risk factors for GDV are present.

Biaxial flexural strength of CAD/CAM ceramics.

PubMed

Buso, L; Oliveira-Júnior, O B; Hiroshi Fujiy, F; Leão Lombardo, G H; Ramalho Sarmento, H; Campos, F; Assunção Souza, R O

2011-06-01

Aim of the study was to evaluate the biaxial flexural strength of ceramics processed using the Cerec inLab system. The hypothesis was that the flexural strength would be influenced by the type of ceramic. Ten samples (ISO 6872) of each ceramic (N.=50/n.=10) were made using Cerec inLab (software Cerec 3D) (Ø:15 mm, thickness: 1.2 mm). Three silica-based ceramics (Vita Mark II [VM], ProCad [PC] and e-max CAD ECAD]) and two yttria-stabilized tetragonal-zirconia-polycrystalline ceramics (Y-TZP) (e-max ZirCad [ZrCAD] and Vita In-Ceram 2000 YZ Cubes [VYZ]) were tested. The samples were finished with wet silicone carbide papers up to 1 200-grit and polished in a polishing machine with diamond paste (3 µm). The samples were then submitted to biaxial flexural strength testing in a universal testing machine (EMIC), 1 mm/min. The data (MPa) were analyzed using the Kruskal-Wallis and Dunn (5%) tests. Scanning electronic microscopy (SEM) was performed on a representative sample from each group. The values (median, mean±sd) obtained for the experimental groups were: VM (101.7, 102.1±13.65 MPa), PC (165.2, 160±34.7 MPa), ECAD (437.2, 416.1±50.1 MPa), ZrCAD (804.2, 800.8±64.47 MPa) and VYZ (792.7, 807±100.7 MPa). The type of ceramic influenced the flexural strength values (P=0.0001). The ceramics ECADa, e-max ZrCADa and VYZa presented similar flexural strength values which were significantly higher than the other groups (PCb and VM IIb), which were similar statistically between them (Dunn's test). The hypothesis was accepted. The polycrystalline ceramics (Y-TZP) should be material chosen for make FPDs because of their higher flexural strength values.

Mesentero-axial gastric volvulus after removal of laparoscopic adjustable gastric band.

PubMed

Pirmadjid, N; Pournaras, D J; Huan, S; Sujendran, V

2017-02-01

Despite the decreasing popularity of gastric banding, a large number of patients still have a band in situ. Although immediate postoperative complications are relatively rare, long-term complications of gastric banding are more common but are not reported to occur after band removal. We report a case of gastric volvulus and subsequent ischaemic perforation in a patient shortly after band removal, resulting in emergency laparotomy and total gastrectomy. Severe continuing pain persisting after band deflation and even gastric band removal should be treated as an emergency and urgent investigation should not be delayed.

Giant colonic volvulus due to colonic pseudo-obstruction

PubMed Central

Karaman, Kerem; Tanoglu, Alpaslan; Beyazit, Yavuz; Han, Ismet

2015-01-01

Acute colonic pseudo-obstruction (ACPO), also known as Ogilvie’s syndrome, is a clinical syndrome characterised by gross dilation of the caecum and right hemicolon, which sometimes extends to the sigmoid colon and rectum in the absence of an anatomic lesion in the intestinal lumen. It is characterised by impaired propulsion of contents of the gastrointestinal tract, which results in a clinical picture of intestinal obstruction. A careful examination of the markedly distended colon can exclude several colonic pathologies, including mechanical obstruction and other causes of toxic megacolon. ACPO can sometimes predispose or mimic colonic volvulus, especially in geriatric patients. PMID:25716038

Rapid Suppression of Onchocerca volvulus Transmission in Two Communities of the Southern Chiapas Focus, Mexico, Achieved by Quarterly Treatments with Mectizan

PubMed Central

Rodríguez-Pérez, Mario A.; Lutzow-Steiner, Miguel A.; Segura-Cabrera, Aldo; Lizarazo-Ortega, Cristian; Domínguez-Vázquez, Alfredo; Sauerbrey, Mauricio; Richards, Frank; Unnasch, Thomas R.; Hassan, Hassan K.; Hernández-Hernández, Raymundo

2008-01-01

The impact of quarterly Mectizan (ivermectin) treatments on transmission, microfiladermia, and ocular lesions was evaluated in two formerly hyperendemic communities (Las Golondrinas and Las Nubes II) located in the main endemic focus for onchocerciasis in Southern Chiapas, Mexico. The data suggest that Onchocerca volvulus transmission has been suppressed after elimination of microfiladermia in these two communities. Increasing the frequency of Mectizan treatment to four times per year appears to have resulted in the rapid suppression of transmission in communities with residual transmission. PMID:18689630

Analysis of Flexural Fatigue Strength of Self Compacting Fibre Reinforced Concrete Beams

NASA Astrophysics Data System (ADS)

Murali, G.; Sudar Celestina, J. P. Arul; Subhashini, N.; Vigneshwari, M.

2017-07-01

This study presents the extensive statistical investigation ofvariations in flexural fatigue life of self-compacting Fibrous Concrete (FC) beams. For this purpose, the experimental data of earlier researchers were examined by two parameter Weibull distribution.Two methods namely Graphical and moment wereused to analyse the variations in experimental data and the results have been presented in the form of probability of survival. The Weibull parameters values obtained from graphical and method of moments are precise. At 0.7 stress level, the fatigue life shows 59861 cyclesfor areliability of 90%.

Topology-optimization-based design method of flexures for mounting the primary mirror of a large-aperture space telescope.

PubMed

Hu, Rui; Liu, Shutian; Li, Quhao

2017-05-20

For the development of a large-aperture space telescope, one of the key techniques is the method for designing the flexures for mounting the primary mirror, as the flexures are the key components. In this paper, a topology-optimization-based method for designing flexures is presented. The structural performances of the mirror system under multiple load conditions, including static gravity and thermal loads, as well as the dynamic vibration, are considered. The mirror surface shape error caused by gravity and the thermal effect is treated as the objective function, and the first-order natural frequency of the mirror structural system is taken as the constraint. The pattern repetition constraint is added, which can ensure symmetrical material distribution. The topology optimization model for flexure design is established. The substructuring method is also used to condense the degrees of freedom (DOF) of all the nodes of the mirror system, except for the nodes that are linked to the mounting flexures, to reduce the computation effort during the optimization iteration process. A potential optimized configuration is achieved by solving the optimization model and post-processing. A detailed shape optimization is subsequently conducted to optimize its dimension parameters. Our optimization method deduces new mounting structures that significantly enhance the optical performance of the mirror system compared to the traditional methods, which only focus on the parameters of existing structures. Design results demonstrate the effectiveness of the proposed optimization method.

Flexural stiffness of the composite steel and fibre-reinforced concrete circular hollow section column

NASA Astrophysics Data System (ADS)

Tretyakov, A.; Tkalenko, I.; Wald, F.; Novak, J.; Stefan, R.; Kohoutková, A.

2017-09-01

The recent development in technology of production and transportation of steel fibre-reinforced concrete enables its utilization in composite steel-concrete structures. This work is a part of a project which focuses on development of mechanical behaviour of circular hollow section (CHS) composite steel and fibre-concrete (SFRC) columns at elevate temperature. Research includes two levels of accuracy/complexity, allowing simplified or advanced approach for design that follows upcoming changes in European standard for composite member design in fire EN1994-1-2 [1]. One part is dedicated to determination and description of flexural stiffness of the SFRC CHS columns. To determinate flexural stiffness were prepared series of pure bending tests at elevated and ambient temperature. Presented paper focuses on the results of the tests and determination of flexural stiffness at ambient temperature. Obtained outputs were compared to data of existing studies about concrete-filled tube members with plain concrete and values analytically calculated according to the existing European standard EN1994-1-1 [2].

Minimum Surface-Effect Microgripper Design for Force-Reflective Telemanipulation of a Microscopic Environment

NASA Technical Reports Server (NTRS)

Goldfarb, Michael; Celanovic, Nikola

1996-01-01

This paper describes the fundamental physical motivations for minimum surface effect design, and presents a microgripper that incorporates a piezoelectric ceramic actuator and a flexure-based structure and transmission. The microgripper serves effectively as a one degree-of-freedom prototype of minimum surface effect micromanipulator design. Data is presented that characterizes the microgripper performance under both pure position and pure force control, followed by a discussion of the attributes and limitations of flexure-based design. The microgripper is interfaced with a force-reflective macrogripper, and the pair controlled with a hybrid position/force scheme. Data is presented that illustrates the effective operation of the telerobotic pair.

Flexure and impact properties of glass fiber reinforced nylon 6-polypropylene composites

NASA Astrophysics Data System (ADS)

Kusaseh, N. M.; Nuruzzaman, D. M.; Ismail, N. M.; Hamedon, Z.; Azhari, A.; Iqbal, A. K. M. A.

2018-03-01

In recent years, polymer composites are rapidly developing and replacing the metals or alloys in numerous engineering applications. These polymer composites are the topic of interests in industrial applications such as automotive and aerospace industries. In the present research study, glass fiber (GF) reinforced nylon 6 (PA6)-polypropylene (PP) composite specimens were prepared successfully using injection molding process. Test specimens of five different compositions such as, 70%PA6+30%PP, 65%PA6+30%PP+5%GF, 60%PA6+30%PP+10%GF, 55%PA6+30%PP+15%GF and 50%PA6+30%PP+20%GF were prepared. In the experiments, flexure and impact tests were carried out. The obtained results revealed that flexure and impact properties of the polymer composites were significantly influenced by the glass fiber content. Results showed that flexural strength is low for pure polymer blend and flexural strength of GF reinforced composite increases gradually with the increase in glass fiber content. Test results also revealed that the impact strength of 70%PA6+30%PP is the highest and 55%PA6+30%PP+15%GF composite shows moderate impact strength. On the other hand, 50%PA6+30%PP+20%GF composite shows low toughness or reduced impact strength.

Development of 1-m primary mirror for a spaceborne camera

NASA Astrophysics Data System (ADS)

Kihm, Hagyong; Yang, Ho-Soon; Rhee, Hyug-Gyo; Lee, Yun-Woo

2015-09-01

We present the development of a 1-m lightweight mirror system for a spaceborne electro-optical camera. The mirror design was optimized to satisfy the performance requirements under launch loads and space environment. The mirror made of Zerodur® has pockets at the back surface and three square bosses at the rim. Metallic bipod flexures support the mirror at the bosses and adjust the mirror's surface distortion due to gravity. We also show an analytical formulation of the bipod flexure, where compliance and stiffness matrices of the bipod flexure are derived to estimate theoretical performance and to make initial design guidelines. Optomechanical performances such as surface distortions due to gravity is explained. Environmental verification of the mirror is achieved by vibration tests.

Reversibility of cardiopulmonary impairment after laparoscopic repair of large hiatal hernia

PubMed Central

Asti, Emanuele; Bonavina, Luigi; Lombardi, Massimo; Bandera, Francesco; Secchi, Francesco; Guazzi, Marco

2015-01-01

Giant hiatus hernia with or without intrathoracic gastric volvulus often presents with symptoms suggestive of both cardiac and pulmonary compression. Cardiopulmonary impairment may be reversible in these patients by laparoscopic crural repair and fundoplication as shown in this case report. Cardiac magnetic resonance and the cardiopulmonary exercise test may help selecting patients for surgery. These preliminary findings led us to start a prospective study using this multimodality diagnostic approach. PMID:26210719

Bacteremia and bacterial translocation in the naturally occurring canine gastric dilatation-volvulus patient.

PubMed

Winkler, Kevin P; Greenfield, Cathy L; Schaeffer, David J

2003-01-01

This prospective study was performed to determine the prevalence of bacteremia in the naturally occurring gastric dilatation-volvulus (GDV) patient, the possible relationship between bacteremia and survival, and whether bacteremia was a result of translocation from the stomach. Blood cultures were collected from each patient. Bacterial cultures were collected from the liver, mesenteric lymph node, and stomach. Forty-three percent of the GDV cases and 40% of the controls developed positive blood cultures. Gram-negative rods were the most frequently isolated organisms. Evidence of bacterial translocation from the stomach could not be demonstrated in GDV patients, and survival was not affected by the presence of bacteremia.

Neonatal intestinal volvulus and preduodenal portal vein associated with situs ambiguus: report of a case.

PubMed

Watanabe, Toshihiko; Nakano, Miwako; Yamazawa, Kazuki; Maeyama, Katsuhiro; Endo, Masao

2011-05-01

Situs ambiguus is a rare lateralization anomaly that is frequently associated with other malformations, including preduodenal portal vein (PDPV), intestinal malrotation, and cardiovascular anomalies. This is a case report on a newborn that was clinically diagnosed with situs ambiguus and midgut volvulus. During surgery the patient was found to have intestinal malrotation, Meckel's diverticulum, and PDPV that was not a direct cause of duodenal obstruction. The patient was treated with Ladd's procedure and resection of Meckel's diverticulum. It is important to be familiar with the spectrum of situs anomalies to prevent trauma to the portal vein with serious complications during surgery.

Gastric ulceration subsequent to partial invagination of the stomach in a dog with gastric dilatation-volvulus.

PubMed

Parton, Amanda T; Volk, Susan W; Weisse, Chick

2006-06-15

CASE DESCRIPTION-An 8-year-old castrated male German Shepherd Dog was evaluated because of abdominal distension, retching, and vomiting. CLINICAL FINDINGS-Gastric dilatation-volvulus was suspected on the basis of the dog's signalment, history, clinical signs, and results of clinicopathologic analyses and abdominal radiography. Celiotomy was performed, and gastric dilatation-volvulus was confirmed along with splenomegaly. Gastric invagination was performed over an area of gastric necrosis. The dog was reevaluated 21 days later after an episode of collapse. Findings of physical examination and clinicopathologic analyses were suggestive of internal hemorrhage. Abdominal ultrasonography and subsequent celiotomy revealed severe gastric ulceration at the gastric invagination site, splenic torsion, and a focal splenic infarct. TREATMENT AND OUTCOME-Splenectomy and gastrectomy of the necrotic tissue were performed. The dog was discharged from the hospital, and the owner was instructed to administer gastroprotectants and feed the dog a bland diet. The dog was reported to be healthy 3.25 years after surgery. CLINICAL RELEVANCE-Findings suggest that complications associated with the gastric invagination procedure include severe gastric ulceration that may require subsequent surgery. Prolonged treatment with gastroprotectants following gastric invagination surgery may be necessary to avoid gastric ulceration in dogs.

A rotating electrical transfer device

NASA Technical Reports Server (NTRS)

Porter, R. S.

1985-01-01

The design, development, and performance characteristics of two roll ring configurations - a roll ring being a device used in transferring electrical energy across a continuously rotating or oscillating interface through one or more flexible rolling contacts, or flexures are described. Emphasis is placed on the design problems and solutions encountered during development in the areas of flexure fatigue, contact electroplating, electrical noise, and control of interface geometry. Also, the present status of each configuration is summarized.

Active Flexural-Slip Faulting: Controls Exerted by Stratigraphy, Geometry, and Fold Kinematics

NASA Astrophysics Data System (ADS)

Li, Tao; Chen, Jie; Thompson Jobe, Jessica A.; Burbank, Douglas W.

2017-10-01

Flexural slip plays an important role in accommodating fold growth, and its topographic expression, flexural-slip fault (FSF) scarps, may be one of the most commonly occurring secondary structures in areas dominated by active thrusts and folds. Where FSF scarps are present and what factors control their occurrence, however, are typically poorly known. Through an investigation of clearly expressed FSF scarps, well-preserved fluvial terraces, and well-exposed bedrock at eight sites in the Pamir-Tian Shan convergent zone and Kuche fold belt, NW China, we summarize the most favorable conditions for active flexural-slip faulting. Our study yields six key results. First, flexural slip operates commonly in well-layered beds, although uncommonly can occur in massive, poorly layered beds as well. Second, in well-layered beds, the slip surface is commonly located either (a) close to the contact of competent and incompetent beds or (b) within thin incompetent beds. Third, FSF scarps are always found overlying steep beds with dips of 30-100°. Fourth, slip surfaces are typically spaced between 10 and 440 m but can reach up to 600 m. Fifth, FSF scarps at most sites can be observed far away from the hinge-migrated fold scarps, suggesting that compared to hinge migration, limb rotation is generally required to accumulate flexural slip and produce associated topographic scarps. Finally, a higher regional convergent rate seems to facilitate the creation of FSF scarps more often than lower rates, whereas well-preserved, old terraces capped by thin deposits are more likely to record FSF scarps than unevenly preserved, young terraces with thick sedimentary caps.

Flexural plate wave devices fabricated from silicon carbide membrane

NASA Astrophysics Data System (ADS)

Diagne, Ndeye Fama

Flexural Plate Wave (FPW) devices fabricated from Silicon Carbide (SiC) membranes are presented here which exhibit electrical and mechanical characteristics in its transfer functions that makes it very useful as a low voltage probe device capable of functioning in small areas that are commonly inaccessible to ordinary devices. The low input impedance characteristic of this current driven device makes it possible for it to operate at very low voltages, thereby reducing the hazards for flammable or explosive areas to be probed. The Flexural Plate Wave (FPW) devices are of a family of gravimetric type sensors that permit direct measurements of the mass of the vibrating element. The primary objective was to study the suitability of Silicon Carbide (SiC) membranes as a replacement of Silicon Nitride (SiN) membrane in flexural plate wave devices developed by Sandia National Laboratories. Fabrication of the Flexural Plate Wave devices involves the overlaying a silicon wafer with membranes of 3C-SiC thin film upon which conducting meander lines are placed. The input excitation energy is in the form of an input current. The lines of current along the direction of the conducting Meander Lines Transducer (MLTs) and the applied perpendicular external magnetic field set up a mechanical wave perpendicular to both, exciting the membrane by means of a Lorentz force, which in turn sets up flexural waves that propagate along the thin membrane. The physical dimensions, the mass density, the tension in the membrane and the meander spacing are physical characteristics that determine resonance frequency of the Flexural Plate Wave (FPW) device. Of primary interest is the determination of the resonant frequency of the silicon carbide membrane as functions of the device physical characteristic parameters. The appropriate transduction scheme with Meander Line Transducers (IDTs) are used to excite the membrane. Equivalent circuit models characterizing the reflection response S11 (amplitude and phase) for a one-port Flexural PlateWave device and the transmission response S21 of a two-port device are used for the development of the equivalent mechanical characteristics.

The relationship between compressive strength and flexural strength of pavement geopolymer grouting material

NASA Astrophysics Data System (ADS)

Zhang, L.; Han, X. X.; Ge, J.; Wang, C. H.

2018-01-01

To determine the relationship between compressive strength and flexural strength of pavement geopolymer grouting material, 20 groups of geopolymer grouting materials were prepared, the compressive strength and flexural strength were determined by mechanical properties test. On the basis of excluding the abnormal values through boxplot, the results show that, the compressive strength test results were normal, but there were two mild outliers in 7days flexural strength test. The compressive strength and flexural strength were linearly fitted by SPSS, six regression models were obtained by linear fitting of compressive strength and flexural strength. The linear relationship between compressive strength and flexural strength can be better expressed by the cubic curve model, and the correlation coefficient was 0.842.

Mechanical properties and flexure behaviour of lightweight foamed concrete incorporating coir fibre

NASA Astrophysics Data System (ADS)

Mohamad, Noridah; Afif Iman, Muhamad; Othuman Mydin, M. A.; Samad, A. A. A.; Rosli, J. A.; Noorwirdawati, A.

2018-04-01

This paper presents an experimental investigation on the mechanical properties and flexural behaviour of lightweight foamed concrete (LFC) with added coir fibre as filler. The compressive strength (Pt), tensile strength (Ft), modulus of elasticity (E), ultimate load and crack pattern of the foamed concrete were determined. The coir fibre was added to the foamed concrete mixture at 0.1%, 0.2% and 0.3% of the total weight of cement. Effects of various percentage of coir fibre used on foam concrete’s mechanical and properties and flexural behaviour were studied and analysed. It was found that the increase percentage of fibre resulted in increase in compressive strength, tensile strength and modulus of elasticity of LFC mixture. LFC with added coir of 0.3% experienced the smallest crack propagation.

A Flexure-Based Mechanism for Precision Adjustment of National Ignition Facility Target Shrouds in Three Rotational Degrees of Freedom

DOE PAGES

Boehm, K. -J.; Gibson, C. R.; Hollaway, J. R.; ...

2016-09-01

This study presents the design of a flexure-based mount allowing adjustment in three rotational degrees of freedom (DOFs) through high-precision set-screw actuators. The requirements of the application called for small but controlled angular adjustments for mounting a cantilevered beam. The proposed design is based on an array of parallel beams to provide sufficiently high stiffness in the translational directions while allowing angular adjustment through the actuators. A simplified physical model in combination with standard beam theory was applied to estimate the deflection profile and maximum stresses in the beams. A finite element model was built to calculate the stresses andmore » beam profiles for scenarios in which the flexure is simultaneously actuated in more than one DOF.« less

Constitutive Behavior and Finite Element Analysis of FRP Composite and Concrete Members.

PubMed

Ann, Ki Yong; Cho, Chang-Geun

2013-09-10

The present study concerns compressive and flexural constitutive models incorporated into an isoparametric beam finite element scheme for fiber reinforced polymer (FRP) and concrete composites, using their multi-axial constitutive behavior. The constitutive behavior of concrete was treated in triaxial stress states as an orthotropic hypoelasticity-based formulation to determine the confinement effect of concrete from a three-dimensional failure surface in triaxial stress states. The constitutive behavior of the FRP composite was formulated from the two-dimensional classical lamination theory. To predict the flexural behavior of circular cross-section with FRP sheet and concrete composite, a layered discretization of cross-sections was incorporated into nonlinear isoparametric beam finite elements. The predicted constitutive behavior was validated by a comparison to available experimental results in the compressive and flexural beam loading test.

Integrated tuned vibration absorbers: a theoretical study.

PubMed

Gardonio, Paolo; Zilletti, Michele

2013-11-01

This article presents a simulation study on two integrated tuned vibration absorbers (TVAs) designed to control the global flexural vibration of lightly damped thin structures subject to broad frequency band disturbances. The first one consists of a single axial switching TVA composed by a seismic mass mounted on variable axial spring and damper elements so that the characteristic damping and natural frequency of the absorber can be switched iteratively to control the resonant response of three flexural modes of the hosting structure. The second one consists of a single three-axes TVA composed by a seismic mass mounted on axial and rotational springs and dampers, which are arranged in such a way that the suspended mass is characterized by uncoupled heave and pitch-rolling vibrations. In this case the three damping and natural frequency parameters of the absorber are tuned separately to control three flexural modes of the hosting structure. The simulation study shows that the proposed single-unit absorbers produce, respectively, 5.3 and 8.7 dB reductions of the global flexural vibration of a rectangular plate between 20 and 120 Hz.

Effects of KMnO4 Treatment on the Flexural, Impact, and Thermal Properties of Sugar Palm Fiber-Reinforced Thermoplastic Polyurethane Composites

NASA Astrophysics Data System (ADS)

Mohammed, A. A.; Bachtiar, D.; Rejab, M. R. M.; Jiang, X. X.; Abas, Falak O.; Abass, Raghad U.; Hasany, S. F.; Siregar, Januar P.

2018-05-01

Global warming has had a great impact on environmental changes since the last decade. Eco-friendly industrial products are of great importance to sustain life on earth, including using natural composites. Natural fibers used as fillers are also environmentally valuable because of their biodegradable nature. However, compatibility issues between the fiber and its respective matrix is a major concern. The present work focused on the study of the flexural, impact, and thermal behaviors of environmentally friendly sugar palm fibers (SPF) incorporated into a composite with thermoplastic polyurethane (TPU). Two techniques (extrusion and compression molding) were used to prepare these composites. The fiber size and dosage were kept constant at 250 µm and 30 wt.% SPF, respectively. The effects of potassium permanganate (KMnO4) treatment on the flexural, impact, and thermal behaviors of the treated SPF with 6% NaOH-reinforced TPU composites were investigated. Three different concentrations of KMnO4 (0.033%, 0.066%, and 0.125%) were studied for this purpose. The characterization of the flexural and impact properties of the new TPU/SPF composites was studied as per American Society for Testing Materials ASTM standards. Thermogravimetric analysis was employed for thermal behavior analysis of the TPU/SPF composites. The best flexural strength, impact strength, and modulus properties (8.118 MPa, 55.185 kJ/m2, and 262.102 MPa, respectively) were obtained with a 0.033% KMnO4-treated sample. However, all flexural strength, impact strength, and modulus properties for the KMnO4-treated samples were lower than the sample treated only with 6% NaOH. The highest thermal stability was also shown by the sample treated with 0.033% KMnO4. Therefore, this method enhanced the thermal properties of the TPU/SPF composites with clear deterioration of the flexural and impact properties.

Acute abdomen in mentally retarded patients: role of aerophagia. Report of nine cases.

PubMed

van der Kolk, M B; Bender, M H; Goris, R J

1999-05-01

Between 1993 and 1996 nine mentally retarded patients presented because of an acute abdomen. All had the habit of aerophagia, diagnosed previously by a general practitioner. Massive distension of the bowel led to ileus, volvulus, and necrosis. After placement of a percutaneous endoscopic gastrostomy catheter or performing a gastrostomy during laparotomy with the intention to use as a desufflator, no recurrence of the signs and symptoms of an acute abdomen were observed.

Food engorgement in 35 dogs (2009-2013) compared with 36 dogs with gastric dilation and volvulus.

PubMed

Smart, Lisa; Reese, Shona; Hosgood, Giselle

2017-11-25

The clinical features and management of food engorgement (FE) in dogs have not been previously described. This retrospective observational study describes characteristics and outcome of 35 dogs with FE, and compares features on presentation to 36 dogs with gastric dilation and volvulus (GDV). Cases were retrospectively reviewed for history, clinical findings and outcome. Gastric distension was measured by caudal gastric margin (CGM), level with lumbar vertebrae, on a lateral abdominal radiograph. Frequent characteristics of dogs with FE included tachycardia, tachypnoea, hyperproteinaemia, increased base excess (BE), mild hypernatraemia and hyperlactataemia. There was overlap in CGM between dogs with GDV (CGM range L3 to >L6) and dogs with FE (CGM range

Minimum surface-effect microgripper design for force-reflective telemanipulation of a microscopic environment

NASA Technical Reports Server (NTRS)

Goldfarb, Michael; Celanovic, Nikola

1996-01-01

This paper describes the fundamental physical motivations for a minimum surface effect design, and presents a microgripper that incorporates a piezoelectric ceramic actuator and a flexure-based structure and transmission. The microgripper serves effectively as a one degree-of-freedom prototype of a minimum surface effect micromanipulator design. Data is presented that characterizes the microgripper performance under both pure position and pure force control, followed by a discussion of the attributes and limitations of flexure-based design. The microgripper is interfaced with a force reflective macrogripper, and the pair is controlled with a hybrid position/force scheme. Data is presented that illustrates the effective operation of the telerobotic pair.

Flexural Properties of PLA Components Under Various Test Condition Manufactured by 3D Printer

NASA Astrophysics Data System (ADS)

Jaya Christiyan, K. G.; Chandrasekhar, U.; Venkateswarlu, K.

2018-06-01

Rapid Prototyping (RP) technologies have emerged as a fabrication method to obtain engineering components in the resent past. Desktop 3D printing, also referred as an additive layer manufacturing technology is a powerful method of RP technique that can fabricate 3 dimensional engineering components. In this method, 3D digital data is converted into real product. In the present investigation, Polylactic Acid (PLA) was considered as a starting material. Flexural strength of PLA material was evaluated using 3-point bend test, as per ASTM D790 standard. Specimens with flat (0°) and vertical (90°) orientation were considered. Moreover, layer thicknesses of 0.2, 0.25, and 0.3 mm were considered. To fabricate these specimens, printing speed of 38 and 52 mm/s was maintained. Nozzle diameter of 0.4 mm with 40 % of infill density were used. Based on the experimental results, it was observed that 0° orientation, 38 mm/s printing speed, and 0.2 mm layer thickness resulted maximum flexural strength, as compared to all other specimens. The improved flexural strength was due to the lower layer thickness (0.2 mm) specimens, as compared with other specimens made of 0.25 and 0.30 mm layer thicknesses. It was concluded that flexural strength properties were greatly influenced by lower the layer thickness, printing speed, and orientation.

Mechanical characterization and structural analysis of recycled fiber-reinforced-polymer resin-transfer-molded beams

NASA Astrophysics Data System (ADS)

Tan, Eugene Wie Loon

1999-09-01

The present investigation was focussed on the mechanical characterization and structural analysis of resin-transfer-molded beams containing recycled fiber-reinforced polymers. The beams were structurally reinforced with continuous unidirectional glass fibers. The reinforcing filler materials consisted entirely of recycled fiber-reinforced polymer wastes (trim and overspray). The principal resin was a 100-percent dicyclo-pentadiene unsaturated polyester specially formulated with very low viscosity for resin transfer molding. Variations of the resin transfer molding technique were employed to produce specimens for material characterization. The basic materials that constituted the structural beams, continuous-glass-fiber-reinforced, recycled-trim-filled and recycled-overspray-filled unsaturated polyesters, were fully characterized in axial and transverse compression and tension, and inplane and interlaminar shear, to ascertain their strengths, ultimate strains, elastic moduli and Poisson's ratios. Experimentally determined mechanical properties of the recycled-trim-filled and recycled-overspray-filled materials from the present investigation were superior to those of unsaturated polyester polymer concretes and Portland cement concretes. Mechanical testing and finite element analyses of flexure (1 x 1 x 20 in) and beam (2 x 4 x 40 in) specimens were conducted. These structurally-reinforced specimens were tested and analyzed in four-point, third-point flexure to determine their ultimate loads, maximum fiber stresses and mid-span deflections. The experimentally determined load capacities of these specimens were compared to those of equivalent steel-reinforced Portland cement concrete beams computed using reinforced concrete theory. Mechanics of materials beam theory was utilized to predict the ultimate loads and mid-span deflections of the flexure and beam specimens. However, these predictions proved to be severely inadequate. Finite element (fracture propagation) analyses of the flexure and beam specimens were also performed. These progressive failure analyses more closely approximated flexural behavior under actual testing conditions by reducing the elastic moduli of elements that were considered to have partially or totally failed. Individual element failures were predicted using the maximum stress, Tsai-Hill and Tsai-Wu failure criteria. Excellent predictions of flexural behavior were attributed to the progressive failure analyses combined with an appropriate failure criterion, and the reliable input material properties that were generated.

Comparison of Flexural Strength of Different CAD/CAM PMMA-Based Polymers.

PubMed

Alp, Gülce; Murat, Sema; Yilmaz, Burak

2018-01-28

To compare the flexural strength of different computer-aided design/computer-aided manufacturing (CAD/CAM) poly(methyl methacrylate)-based (PMMA) polymers and conventional interim resin materials after thermocycling. Rectangular-shaped specimens (n = 15, for each material) (25 × 2 × 2 mm 3 ) were fabricated from 3 CAD/CAM PMMA-based polymers (Telio CAD [T]; M-PM-Disc [M]; Polident-PMMA [P]), 1 bis-acrylate composite resin (Protemp 4 [PT]), and 1 conventional PMMA (ArtConcept Artegral Dentine [C]) according to ISO 10477:2004 Standards (Dentistry-Polymer-Based Crown and Bridge Materials). The specimens were subjected to 10,000 thermocycles (5 to 55°C). Three-point flexural strength of the specimens was tested in a universal testing machine at a 1.0 mm/min crosshead speed, and the flexural strength data (σ) were calculated (MPa). The flexural strength values were statistically analyzed using 1-way ANOVA, and Tukey HSD post-hoc test for multiple comparisons (α = 0.05). Flexural strength values ranged between 66.1 ± 13.1 and 131.9 ± 19.8 MPa. There were significant differences among the flexural strengths of tested materials, except for between T and P CAD/CAM PMMA-based polymers (p > 0.05). CAD/CAM PMMA-based polymer M had the highest flexural strength and conventional PMMA had the lowest (p < 0.05). CAD/CAM PMMA-based T and P polymers had significantly higher flexural strength than the bis-acrylate composite resin (p < 0.05), and conventional PMMA (p < 0.0001), and significantly lower flexural strength compared to CAD/CAM PMMA-based M (p < 0.05). The flexural strength of CAD/CAM PMMA-based polymers was greater than the flexural strength of bis-acrylate composite resin, which had a greater flexural strength compared to conventional PMMA resin. © 2018 by the American College of Prosthodontists.

Stress analysis of the space telescope focal plane structure joint

NASA Technical Reports Server (NTRS)

Foster, W. A., Jr.; Shoemaker, W. L.

1985-01-01

Two major efforts were begun concerning the Space Telescope focal plane structure joint. The 3-D solid finite element modeling of the bipod flexure plate was carried out. Conceptual models were developed for the load transfer through the three major bolts to the flexure plate. The flexure plate drawings were reconstructed using DADAM for the purpose of developing a file from which the coordinates of any point on the flexure plate could be determined and also to locate the attachment points of the various components which connect with the flexure plate. For modeling convenience the CADAM drawing of the flexure plate has been divided into several regions which will be subdivided into finite elements using MSGMESH, which is a finite element mesh generator available with MSC/NASTRAN. In addition to the CADAM work on the flexure plate, an effort was also begun to develop computer aided drawings of the peripheral beam which will be used to assist in modeling the connection between it and the flexure plate.

Stage-specific Proteomes from Onchocerca ochengi, Sister Species of the Human River Blindness Parasite, Uncover Adaptations to a Nodular Lifestyle.

PubMed

Armstrong, Stuart D; Xia, Dong; Bah, Germanus S; Krishna, Ritesh; Ngangyung, Henrietta F; LaCourse, E James; McSorley, Henry J; Kengne-Ouafo, Jonas A; Chounna-Ndongmo, Patrick W; Wanji, Samuel; Enyong, Peter A; Taylor, David W; Blaxter, Mark L; Wastling, Jonathan M; Tanya, Vincent N; Makepeace, Benjamin L

2016-08-01

Despite 40 years of control efforts, onchocerciasis (river blindness) remains one of the most important neglected tropical diseases, with 17 million people affected. The etiological agent, Onchocerca volvulus, is a filarial nematode with a complex lifecycle involving several distinct stages in the definitive host and blackfly vector. The challenges of obtaining sufficient material have prevented high-throughput studies and the development of novel strategies for disease control and diagnosis. Here, we utilize the closest relative of O. volvulus, the bovine parasite Onchocerca ochengi, to compare stage-specific proteomes and host-parasite interactions within the secretome. We identified a total of 4260 unique O. ochengi proteins from adult males and females, infective larvae, intrauterine microfilariae, and fluid from intradermal nodules. In addition, 135 proteins were detected from the obligate Wolbachia symbiont. Observed protein families that were enriched in all whole body extracts relative to the complete search database included immunoglobulin-domain proteins, whereas redox and detoxification enzymes and proteins involved in intracellular transport displayed stage-specific overrepresentation. Unexpectedly, the larval stages exhibited enrichment for several mitochondrial-related protein families, including members of peptidase family M16 and proteins which mediate mitochondrial fission and fusion. Quantification of proteins across the lifecycle using the Hi-3 approach supported these qualitative analyses. In nodule fluid, we identified 94 O. ochengi secreted proteins, including homologs of transforming growth factor-β and a second member of a novel 6-ShK toxin domain family, which was originally described from a model filarial nematode (Litomosoides sigmodontis). Strikingly, the 498 bovine proteins identified in nodule fluid were strongly dominated by antimicrobial proteins, especially cathelicidins. This first high-throughput analysis of an Onchocerca spp. proteome across the lifecycle highlights its profound complexity and emphasizes the extremely close relationship between O. ochengi and O. volvulus The insights presented here provide new candidates for vaccine development, drug targeting and diagnostic biomarkers. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Stage-specific Proteomes from Onchocerca ochengi, Sister Species of the Human River Blindness Parasite, Uncover Adaptations to a Nodular Lifestyle*

PubMed Central

Armstrong, Stuart D.; Xia, Dong; Bah, Germanus S.; Krishna, Ritesh; Ngangyung, Henrietta F.; LaCourse, E. James; McSorley, Henry J.; Kengne-Ouafo, Jonas A.; Chounna-Ndongmo, Patrick W.; Wanji, Samuel; Enyong, Peter A.; Taylor, David W.; Blaxter, Mark L.; Wastling, Jonathan M.; Tanya, Vincent N.; Makepeace, Benjamin L.

2016-01-01

Despite 40 years of control efforts, onchocerciasis (river blindness) remains one of the most important neglected tropical diseases, with 17 million people affected. The etiological agent, Onchocerca volvulus, is a filarial nematode with a complex lifecycle involving several distinct stages in the definitive host and blackfly vector. The challenges of obtaining sufficient material have prevented high-throughput studies and the development of novel strategies for disease control and diagnosis. Here, we utilize the closest relative of O. volvulus, the bovine parasite Onchocerca ochengi, to compare stage-specific proteomes and host-parasite interactions within the secretome. We identified a total of 4260 unique O. ochengi proteins from adult males and females, infective larvae, intrauterine microfilariae, and fluid from intradermal nodules. In addition, 135 proteins were detected from the obligate Wolbachia symbiont. Observed protein families that were enriched in all whole body extracts relative to the complete search database included immunoglobulin-domain proteins, whereas redox and detoxification enzymes and proteins involved in intracellular transport displayed stage-specific overrepresentation. Unexpectedly, the larval stages exhibited enrichment for several mitochondrial-related protein families, including members of peptidase family M16 and proteins which mediate mitochondrial fission and fusion. Quantification of proteins across the lifecycle using the Hi-3 approach supported these qualitative analyses. In nodule fluid, we identified 94 O. ochengi secreted proteins, including homologs of transforming growth factor-β and a second member of a novel 6-ShK toxin domain family, which was originally described from a model filarial nematode (Litomosoides sigmodontis). Strikingly, the 498 bovine proteins identified in nodule fluid were strongly dominated by antimicrobial proteins, especially cathelicidins. This first high-throughput analysis of an Onchocerca spp. proteome across the lifecycle highlights its profound complexity and emphasizes the extremely close relationship between O. ochengi and O. volvulus. The insights presented here provide new candidates for vaccine development, drug targeting and diagnostic biomarkers. PMID:27226403

Miserere colic (Miserere mei). Contribution on etymology and clinical features; hypothesis on its appearance in medical literature during centuries 17th-18th.

PubMed

Acea Nebril, B

2001-03-01

The definition of ileus has undergone deep changes over the last three millennia. The term ileus was originally used in Classic Greece to describe a common cause of intestinal obstruction, and subsequently the Romans would often translate it into the Latin word volvulus. During the Renaissance, ileus, volvulus and intussusception became synonymous with a vulgar term--Miserere Mei or Miserere colic--whose origin and evolution are still much of a mystery. This paper provides some historical investigation on the Miserere Mei or Miserere colic, with the aim of discussing its evolution within medical literature during the 17th and 18th centuries.

Effects of slag on flexural strength of slurry infiltrated fibrous concrete

NASA Astrophysics Data System (ADS)

Elavarasi, D.; Saravana Raja Mohan, K.; Parthasarathy, P.; Dinesh, T.

2017-07-01

Slurry infiltrated fibrous concrete is one of the new advanced concrete composite which differs from method of fabrication and composition of the matrix. Extensive research is being carried out on alternative binders or supplements to cement aiming to reduce environmental impact. However, little has been published to investigate the structural behaviour of SIFCON incorporating with mineral admixtures, particularly as regards its ultrahigh ductility, which may alter the mode of failure from brittle to the more desirable ductile. An experimental study was carried out to investigate the flexural behavior of SIFCON containing three different percentage of fibre content 6%,8% &10% with incorporation of optimum dosage of blast furnace slag replaced by cement. Strength characteristics such as Compressive strength and splitting tensile strength test were carry out for SIFCON incorporating 10% of fibre content and different percentage of slag (0, 15, 30, 45, 60%&75%) to optimize the replacement level. The test results found that the maximum strengths were attained at 30% of blast furnace slag replaced by cement. To study the flexural behavior of SIFCON beam of size 1.2x0.1x0.2m containing different percentages (6%, 8% & 10%) fibre content incorporating with and without the optimum percentage of slag were cast and tested. Both flexural strength and Load displacement characteristics of the specimens were studied under flexure. The outcomespresentedfromtest resultshave been compared. The test results reveals that the flexural strength, toughness, ductility and stiffness characteristics were significantly improved due to incorporation of optimum dosage of slag enhancing when compared to without mineral admixtures also compared to conventional concrete(RCC). Major conclusions were drawn from the investigations which are presented.

Flexural modeling of the elastic lithosphere at an ocean trench: A parameter sensitivity analysis using analytical solutions

NASA Astrophysics Data System (ADS)

Contreras-Reyes, Eduardo; Garay, Jeremías

2018-01-01

The outer rise is a topographic bulge seaward of the trench at a subduction zone that is caused by bending and flexure of the oceanic lithosphere as subduction commences. The classic model of the flexure of oceanic lithosphere w (x) is a hydrostatic restoring force acting upon an elastic plate at the trench axis. The governing parameters are elastic thickness Te, shear force V0, and bending moment M0. V0 and M0 are unknown variables that are typically replaced by other quantities such as the height of the fore-bulge, wb, and the half-width of the fore-bulge, (xb - xo). However, this method is difficult to implement with the presence of excessive topographic noise around the bulge of the outer rise. Here, we present an alternative method to the classic model, in which lithospheric flexure w (x) is a function of the flexure at the trench axis w0, the initial dip angle of subduction β0, and the elastic thickness Te. In this investigation, we apply a sensitivity analysis to both methods in order to determine the impact of the differing parameters on the solution, w (x). The parametric sensitivity analysis suggests that stable solutions for the alternative approach requires relatively low β0 values (<15°), which are consistent with the initial dip angles observed in seismic velocity-depth models across convergent margins worldwide. The predicted flexure for both methods are compared with observed bathymetric profiles across the Izu-Mariana trench, where the old and cold Pacific plate is characterized by a pronounced outer rise bulge. The alternative method is a more suitable approach, assuming that accurate geometric information at the trench axis (i.e., w0 and β0) is available.

Comparison of flexural properties of aramid-reinforced pultrusions having varied matrices, pretreatments and postcures

NASA Technical Reports Server (NTRS)

Wilson, Maywood L.; Johnson, Gary S.; Macconochie, Ian O.

1987-01-01

Aramid-reinforced composite materials of equal fiber volume and varied polymer thermoset matrices were pultruded and flexurally tested to failure. The objective was to improve the flexural properties of aramid-reinforced pultrusions. Pultrusions of both sized and unsized aramid fiber with four different resin systems were compared to determine the effects of sizing compounds and postcuring on flexural strength, fiber wettability, and fiber-to-resin interface bonding. Improvements in flexural strength resulting from pretreatments with the sizing solutions used were marginal. The most significant improvements in flexural properties resulted from postcuring. Flexural strengths ranged from a low of 39,647 psi (273MPa) to a high of 80,390 psi (554 MPa), an overall increase of 103 percent. The fact that postcuring improved the flexural properties of the pultrusions of the four resin systems indicates that a full cure did not occur in any of the resin systems during the pultrusion process. The increased flexural strengths of the polyester and vinyl ester pultrusions were the most surprising. The four resin systems examined were Interplastic Corporation VE 8300 vinyl ester, Ashland Chemical Company Aropol 7430 Polyester, and Shell Chemical Company Epon 9302 and Epon 9310 epoxides.

Mechanical design of deformation compensated flexural pivots structured for linear nanopositioning stages

DOEpatents

Shu, Deming; Kearney, Steven P.; Preissner, Curt A.

2015-02-17

A method and deformation compensated flexural pivots structured for precision linear nanopositioning stages are provided. A deformation-compensated flexural linear guiding mechanism includes a basic parallel mechanism including a U-shaped member and a pair of parallel bars linked to respective pairs of I-link bars and each of the I-bars coupled by a respective pair of flexural pivots. The basic parallel mechanism includes substantially evenly distributed flexural pivots minimizing center shift dynamic errors.

Helical comb magnetostrictive patch transducers for inspecting spiral welded pipes using flexural guided waves.

PubMed

Zhang, Xiaowei; Tang, Zhifeng; Lv, Fuzai; Pan, Xiaohong

2017-02-01

A wavefront analysis indicates that a flexural wave propagates at a helix angle with respect to the pipe axis. The expression for calculation of the helix angle for each flexural mode is given, and the helix angle dispersion curves for flexural modes are calculated. According to the new understanding of flexural guided waves, a helical comb magnetostrictive patch transducer (HCMPT) is proposed for selectively exciting a single predominant flexural torsional guided wave in a pipe and inspecting spiral welded pipes using flexural waves. A HCMPT contains a pre-magnetized magnetostrictive patch that is helically coupled with the outer surface of a pipe, and a novel compound comb coil that is wrapped around the helical magnetostrictive patch. The proposed wideband HCMPT possesses the direction control ability. A verification experiment indicates that flexural torsional mode T(3,1) at center frequency f=64kHz is effectively actuated by a HCMPT with 13-degree helix angle. Flexural torsional modes T(N,1) with circumferential order N equals 1-5 are selected to inspect a seamless steel pipe, artificial defects are effectively detected by the proposed HCMPT. A 20-degree HCMPT is adopted to inspect a spiral welded pipe, an artificial notch with cross section loss CSL=2.7% is effectively detected by using flexural waves. Copyright © 2016 Elsevier B.V. All rights reserved.

A 3D printed electromagnetic nonlinear vibration energy harvester

NASA Astrophysics Data System (ADS)

Constantinou, P.; Roy, S.

2016-09-01

A 3D printed electromagnetic vibration energy harvester is presented. The motion of the device is in-plane with the excitation vibrations, and this is enabled through the exploitation of a leaf isosceles trapezoidal flexural pivot topology. This topology is ideally suited for systems requiring restricted out-of-plane motion and benefits from being fabricated monolithically. This is achieved by 3D printing the topology with materials having a low flexural modulus. The presented system has a nonlinear softening spring response, as a result of designed magnetic force interactions. A discussion of fatigue performance is presented and it is suggested that whilst fabricating, the raster of the suspension element is printed perpendicular to the flexural direction and that the experienced stress is as low as possible during operation, to ensure longevity. A demonstrated power of ˜25 μW at 0.1 g is achieved and 2.9 mW is demonstrated at 1 g. The corresponding bandwidths reach up-to 4.5 Hz. The system’s corresponding power density of ˜0.48 mW cm-3 and normalised power integral density of 11.9 kg m-3 (at 1 g) are comparable to other in-plane systems found in the literature.

Late Cenozoic flexural deformation of the middle U.S. Atlantic passive margin

NASA Technical Reports Server (NTRS)

Pazzaglia, Frank J.; Gardner, Thomas, W.

1994-01-01

Despite the century-long recognition of regional epeirogeny along the middle Atlantic passive margin, relatively few studies have focused on understanding postrift uplift mechanisms. Here, we demonstrate that epeirogenic uplift of the central Appalachian Piedmont and subsidence of the Salisbury Embayment represent first-order, flexural isostatic processes driven by continental denudation and offshore deposition. Our results show that regional epeirogenic processes, present on all Atlantic-type passive margins, are best resolved by specific stratigraphic and geomorphic relationships, rather than topography. A simple one-dimensional geodynamic model, constrained by well-dated Baltimore Canyon trough, Coastal Plain, and lower Susquehanna River (piedmont) stratigraphy, simulates flexural deforamtion of the U.S. Atlantic margin. The model represents the passive margin lithosphree as a uniformly thick elastic plate, without horizontal compressive stresses, that deforms flexurally under the stress of strike-averaged, vertically applied line loads. Model results illustrate a complex interaction among margin stratigraphy and geomorphology, the isostatic repsonse to denudational and depositional processes, and the modulating influence of exogenic forces such as eustasy. The current elevation, with respect to modern sea level, of fluvial terraces and correlateive Coastal Plain deposits or unconformities is successfully predicted through the synthesis of paleotopography, eustatic change, and margin flexure. Results suggest that the middle U.S. Atlantic margin landward of East Coast Magnetic Anomaly is underlain by lithoshpere with an average elastic thickness of 40 km (flexural rigidity, D = 4 X 10(exp 23) N m), the margin experience an average, long-term denudation rate of approximately 10m/m.y., and the Piedmont has been flexurally upwaped between 35 and 130 meters in the last 15 m.y. Long term isostatic continental uplift resulting rom denudation and basin subsidence resulting rom sediment loading are accomodated primately by a convex-up flexural hinge, physiographically represented by the Fall Zone. Our results elucidate an inherent danger in using topography alone to constrain late-stage passive margin deformation mechanisms. Only through careful synthesis of field stratigraphic and geomorphic elements such as fluvial terraces, Coastal Plain deposits, and offshore stratigraphy can age control be extended from the offshore depositional setting to the erosionally dominated continent. This sudy demonstrates that despite a relatively subdued topography, the middle U.S. Atlantic margin experiences progressive flexural isostatic deformation similar to that proposed for high-relief margins characterized by great escarpments. Thus margin topographic diversity remains a function of other factors, such as lithospheric composition and/or structure, supracrustal stratigraphy and structure, degree of drainage integration, drainage divide migration and climate.

Mortality and morbidity due to gastric dilatation-volvulus syndrome in pedigree dogs in the UK.

PubMed

Evans, Katy M; Adams, Vicki J

2010-07-01

To estimate breed-specific risk of death due to, and prevalence of, gastric dilatation-volvulus (GDV) in UK pedigree dogs. Data were available on the reported cause of and age at death and occurrence of and age at diagnosis of disease from the 2004 purebred dog health survey. A total of 15,881 dogs of 165 breeds had died in the previous 10 years; GDV was the cause of death in 65 breeds. There were 36,006 live dogs of 169 breeds of which 48 breeds had experienced > or =1 episodes of GDV. Prevalence ratios were used to estimate breed-specific GDV mortality and morbidity risks. Gastric dilatation-volvulus was the cause of death for 389 dogs, representing 2.5% (95% CI: 2.2-2.7) of all deaths reported and the median age at death was 7.92 years. There were 253 episodes in 238 live dogs. The median age at first diagnosis was five years. Breeds at greatest risk of GDV mortality were the bloodhound, Grand Bleu de Gascogne, German longhaired pointer and Neapolitan mastiff. Breeds at greatest risk of GDV morbidity were the Grand Bleu de Gascogne, bloodhound, otterhound, Irish setter and Weimaraner. These results suggest that 16 breeds, mainly large/giant, are at increased risk of morbidity/mortality due to GDV.

Detection of Onchocerca volvulus (Nematoda: Onchocercidae) infection in vectors from Amazonian Brazil following mass Mectizan distribution.

PubMed

Marchon-Silva, Verônica; Caër, Julien Charles; Post, Rory James; Maia-Herzog, Marilza; Fernandes, Octavio

2007-05-01

Detection of Onchocerca volvulus in Simulium populations is of primary importance in the assessment of the effectiveness of onchocerciasis control programs. In Brazil, the main focus of onchocerciasis is in the Amazon region, in a Yanomami reserve. The main onchocerciasis control strategy in Brazil is the semi-annually mass distribution of the microfilaricide ivermectin. In accordance with the control strategy for the disease, polymerase chain reaction (PCR) was applied in pools of simuliids from the area to detect the helminth infection in the vectors, as recommended by the Onchocerciasis Elimination Program for the Americas and the World Health Organization. Systematic sampling was performed monthly from September 1998 to October 1999, and a total of 4942 blackflies were collected from two sites (2576 from Balawaú and 2366 from Toototobi). The molecular methodology was found to be highly sensitive and specific for the detection of infected and/or infective blackflies in pools of 50 blackflies. The results from the material collected under field conditions showed that after the sixth cycle of distribution of ivermectin, the prevalence of infected blackflies with O. volvulus had decreased from 8.6 to 0.3% in Balawaú and from 4 to 0.1% in Toototobi.

Effect of fiber fibrillation on impact and flexural strength of coir fiber reinforced epoxy hybrid composites

NASA Astrophysics Data System (ADS)

Mawardi, I.; Jufriadi; Hanif

2018-03-01

This study aims to develop fiber-reinforced epoxy resin composites. This study presents the effect of fiber fibrillation on the impact and flextural strength of the epoxy hybrid composite reinforced by coir fiber. Coir is soaked in 5% NaOH solution for 5 hours. Then fiber is rocessed using a blender of 2000 rpm density fibrillation. The length of time the fibrillation varied for 10, 20 and 30 minutes. Volume fraction of 30% fiber and matrix 70% composited. The composite uses a matrix of epoxy by hand lay up method. The implemented tests are impact and flexural tests. The test results show fiber fibrillation treatment can improve the composite mechanical properties. The highest impact and flexural strength, 24.45 kJ/m2 and 87.91 MPa were produced with fiber fibrillation for 10 minutes.

Constitutive Behavior and Finite Element Analysis of FRP Composite and Concrete Members

PubMed Central

Ann, Ki Yong; Cho, Chang-Geun

2013-01-01

The present study concerns compressive and flexural constitutive models incorporated into an isoparametric beam finite element scheme for fiber reinforced polymer (FRP) and concrete composites, using their multi-axial constitutive behavior. The constitutive behavior of concrete was treated in triaxial stress states as an orthotropic hypoelasticity-based formulation to determine the confinement effect of concrete from a three-dimensional failure surface in triaxial stress states. The constitutive behavior of the FRP composite was formulated from the two-dimensional classical lamination theory. To predict the flexural behavior of circular cross-section with FRP sheet and concrete composite, a layered discretization of cross-sections was incorporated into nonlinear isoparametric beam finite elements. The predicted constitutive behavior was validated by a comparison to available experimental results in the compressive and flexural beam loading test. PMID:28788312

Monolithic Flexure Pre-Stressed Ultrasonic Horns

NASA Technical Reports Server (NTRS)

Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Allen, Phillip Grant (Inventor); Bao, Xiaoqi (Inventor); Bar-Cohen, Yoseph (Inventor)

2016-01-01

A monolithic ultrasonic horn where the horn, backing, and pre-stress structures are combined in a single monolithic piece is disclosed. Pre-stress is applied by external flexure structures. The provision of the external flexures has numerous advantages including the elimination of the need for a pre-stress bolt. The removal of the pre-stress bolt eliminates potential internal electric discharge points in the actuator. In addition, it reduces the chances of mechanical failure in the actuator stacks that result from the free surface in the hole of conventional ring stacks. In addition, the removal of the stress bolt and the corresponding reduction in the overall number of parts reduces the overall complexity of the resulting ultrasonic horn actuator and simplifies the ease of the design, fabrication and integration of the actuator of the present invention into other structures.

Monolithic Flexure Pre-Stressed Ultrasonic Horns

NASA Technical Reports Server (NTRS)

Bao, Xiaoqi (Inventor); Bar-Cohen, Yoseph (Inventor); Badescu, Mircea (Inventor); Allen, Phillip Grant (Inventor); Sherrit, Stewart (Inventor)

2015-01-01

A monolithic ultrasonic horn where the horn, backing, and pre-stress structures are combined in a single monolithic piece is disclosed. Pre-stress is applied by external flexure structures. The provision of the external flexures has numerous advantages including the elimination of the need for a pre-stress bolt. The removal of the pre-stress bolt eliminates potential internal electric discharge points in the actuator. In addition, it reduces the chances of mechanical failure in the actuator stacks that result from the free surface in the hole of conventional ring stacks. In addition, the removal of the stress bolt and the corresponding reduction in the overall number of parts reduces the overall complexity of the resulting ultrasonic horn actuator and simplifies the ease of the design, fabrication and integration of the actuator of the present invention into other structures.

Accelerated Testing of Polymeric Composites Using the Dynamic Mechanical Analyzer

NASA Technical Reports Server (NTRS)

Abdel-Magid, Becky M.; Gates, Thomas S.

2000-01-01

Creep properties of IM7/K3B composite material were obtained using three accelerated test methods at elevated temperatures. Results of flexural creep tests using the dynamic mechanical analyzer (DMA) were compared with results of conventional tensile and compression creep tests. The procedures of the three test methods are described and the results are presented. Despite minor differences in the time shift factor of the creep compliance curves, the DMA results compared favorably with the results from the tensile and compressive creep tests. Some insight is given into establishing correlations between creep compliance in flexure and creep compliance in tension and compression. It is shown that with careful consideration of the limitations of flexure creep, a viable and reliable accelerated test procedure can be developed using the DMA to obtain the viscoelastic properties of composites in extreme environments.

Subsidence of a volcanic basin by flexure and lower crustal flow: The eastern Snake River Plain, Idaho

NASA Astrophysics Data System (ADS)

McQuarrie, Nadine; Rodgers, David W.

1998-04-01

The Eastern Snake River Plain (ESRP) is a linear volcanic basin interpreted by many workers to reflect late Cenozoic migration of North America over the Yellowstone hotspot. Thermal subsidence of this volcanic province with respect to Yellowstone has been documented by several workers, but no one has characterized subsidence with respect to the adjacent Basin and Range Province. This paper documents crustal flexure along the northwest edge of the ESRP, uses flexure to model the dimensions of a dense load beneath the basin, and presents evidence in support of density-driven subsidence and lower crustal flow away from the basin. Crustal flexure adjacent to the ESRP is reflected by the attitudes of Mesozoic fold hinges and Neogene volcanic rocks. Fold hinges formed with a subhorizontal plunge and a trend perpendicular to the ESRP but now show a southward plunge near the ESRP of as much as 20°-25°. We present a contour map of equal fold plunges proximal to the ESRP that shows flexure is roughly parallel to and extends 10-20 km north of the average edge of the ESRP. Flexural profiles indicate the minimum amount of ESRP subsidence, with respect to the Basin and Range; subsidence ranges from 4.5 to 8.5 km. The structural contour map and published seismic and gravity data were used to develop and constrain flexural subsidence models. These models indicate the flexed crust is very weak (flexural parameter of 4-10 km), interpreted to be a result of the high heat flow of the ESRP. Assuming subsidence was induced by emplacement of a dense crustal layer beneath the ESRP, a midcrustal "sill" identified in previous seismic surveys is too wide and probably too thin to produce the measured flexure. New dimensions include a thickness of 17-25 km and a half width of 40-50 km, which place the edge of the sill beneath the edge of the ESRP. The dimensions of the ESRP sill are based on isostatic compensation in the lower crust because compensation in the asthenosphere requires an unreasonable sill thickness of 30+ km and because ESRP seismic, gravity, and heat flow data support lower crustal compensation. Density-driven lower crustal flow away from the ESRP is proposed to accommodate subsidence and maintain isostatic equilibrium. Timing of subsidence is constrained by ESRP exploratory wells, where 6.6 Ma rhyolites at a depth of 1.5 km indicate most subsidence occurred prior to their emplacement, and by strong spatial correlations between plunge contours and Quaternary volcanic rift zones. Two processes interpreted to contribute to the load include an extensive midcrustal mafic load emplaced at ˜10 Ma, which provided the heat source for the initial rhyolitic volcanism on the ESRP, and continuing, localized loads from dikes and sills associated with Quaternary basalts. Widespread ˜10 Ma magmatism and subsidence conflicts with simple time-transgressive migration of the Yellowstone hotspot, indicating a need for revision of the hotspot paradigm.

Acute gastric volvulus associated with wandering spleen in an adult treated laparoscopically after endoscopic reduction: a case report.

PubMed

Omata, Jiro; Utsunomiya, Katsuyuki; Kajiwara, Yoshiki; Takahata, Risa; Miyasaka, Nobuo; Sugasawa, Hidekazu; Sakamoto, Naoko; Yamagishi, Yoji; Fukumura, Makiko; Kitagawa, Daiki; Konno, Mitsuhiko; Okusa, Yasushi; Murayama, Michinori

2016-12-01

A 43-year-old female was referred to our hospital for sudden onset of abdominal pain, fullness, and vomiting. Physical examination revealed abdominal distension with mild epigastric tenderness. Abdominal radiography showed massive gastric distension and plain computed tomography (CT) a markedly enlarged stomach filled with gas and fluid. A large volume of gastric contents was suctioned out via a nasogastric (NG) tube. Contrast-enhanced CT showed a grossly distended stomach with displacement of the antrum above the gastroesophageal junction, and the spleen was dislocated inferiorly. Upper gastrointestinal (GI) series showed the greater curvature to be elevated and the gastric fundus to be lower than normal. Acute mesenteroaxial gastric volvulus was diagnosed. GI endoscopy showed a distortion of the gastric anatomy with difficulty intubating the pylorus. Various endoscopic maneuvers were required to reposition the stomach, and the symptoms showed immediate and complete solution. GI fluoroscopy was performed 3 days later. Initially, most of the contrast medium accumulated in the fundus, which was drawn prominently downward, and then began flowing into the duodenum with anteflexion. Elective laparoscopic surgery was performed 1 month later. The stomach was in its normal position, but the fundus was folded posteroinferiorly. The spleen attached to the fundus was normal in size but extremely mobile. We diagnosed a wandering spleen based on the operative findings. Gastropexy was performed for the treatment of gastric volvulus and wandering spleen. The patient remained asymptomatic, and there was no evidence of recurrence during a follow-up period of 24 months. This report describes a rare adult case of acute gastric volvulus associated with wandering spleen. Because delay in treatment can result in lethal complications, it is critical to provide a prompt and correct diagnosis and surgical intervention. We advocate laparoscopic surgery after endoscopic reduction because it is a safe and effective procedure with lower invasiveness.

Report of the first international workshop on onchocerciasis-associated epilepsy.

PubMed

Colebunders, Robert; Mandro, Michel; Njamnshi, Alfred K; Boussinesq, Michel; Hotterbeekx, An; Kamgno, Joseph; O'Neill, Sarah; Hopkins, Adrian; Suykerbuyk, Patrick; Basáñez, Maria-Gloria; Post, Rory J; Pedrique, Belén; Preux, Pierre-Marie; Stolk, Wilma A; Nutman, Thomas B; Idro, Richard

2018-03-22

Recently, several epidemiological studies performed in Onchocerca volvulus-endemic regions have suggested that onchocerciasis-associated epilepsy (OAE) may constitute an important but neglected public health problem in many countries where onchocerciasis is still endemic. On October 12-14 th 2017, the first international workshop on onchocerciasis-associated epilepsy (OAE) was held in Antwerp, Belgium. The workshop was attended by 79 participants from 20 different countries. Recent research findings strongly suggest that O. volvulus is an important contributor to epilepsy, particularly in meso- and hyperendemic areas for onchocerciasis. Infection with O. volvulus is associated with a spectrum of epileptic seizures, mainly generalised tonic-clonic seizures but also atonic neck seizures (nodding), and stunted growth. OAE is characterised by an onset of seizures between the ages of 3-18 years. Multidisciplinary working groups discussed topics such as how to 1) strengthen the evidence for an association between onchocerciasis and epilepsy, 2) determine the burden of disease caused by OAE, 3) prevent OAE, 4) improve the treatment/care for persons with OAE and affected families, 5) identify the pathophysiological mechanism of OAE, and 6) deal with misconceptions, stigma, discrimination and gender violence associated with OAE. An OAE Alliance was created to increase awareness about OAE and its public health importance, stimulate research and disseminate research findings, and create partnerships between OAE researchers, communities, advocacy groups, ministries of health, non-governmental organisations, the pharmaceutical industry and funding organizations. Although the exact pathophysiological mechanism underlying OAE remains unknown, there is increasing evidence that by controlling and eliminating onchocerciasis, OAE will also disappear. Therefore, OAE constitutes an additional argument for strengthening onchocerciasis elimination efforts. Given the high numbers of people with epilepsy in O. volvulus-endemic regions, more advocacy is urgently needed to provide anti-epileptic treatment to improve the quality of life of these individuals and their families.

Oligonucleotide Based Magnetic Bead Capture of Onchocerca volvulus DNA for PCR Pool Screening of Vector Black Flies

PubMed Central

Gopal, Hemavathi; Hassan, Hassan K.; Rodríguez-Pérez, Mario A.; Toé, Laurent D.; Lustigman, Sara; Unnasch, Thomas R.

2012-01-01

Background Entomological surveys of Simulium vectors are an important component in the criteria used to determine if Onchocerca volvulus transmission has been interrupted and if focal elimination of the parasite has been achieved. However, because infection in the vector population is quite rare in areas where control has succeeded, large numbers of flies need to be examined to certify transmission interruption. Currently, this is accomplished through PCR pool screening of large numbers of flies. The efficiency of this process is limited by the size of the pools that may be screened, which is in turn determined by the constraints imposed by the biochemistry of the assay. The current method of DNA purification from pools of vector black flies relies upon silica adsorption. This method can be applied to screen pools containing a maximum of 50 individuals (from the Latin American vectors) or 100 individuals (from the African vectors). Methodology/Principal Findings We have evaluated an alternative method of DNA purification for pool screening of black flies which relies upon oligonucleotide capture of Onchocerca volvulus genomic DNA from homogenates prepared from pools of Latin American and African vectors. The oligonucleotide capture assay was shown to reliably detect one O. volvulus infective larva in pools containing 200 African or Latin American flies, representing a two-four fold improvement over the conventional assay. The capture assay requires an equivalent amount of technical time to conduct as the conventional assay, resulting in a two-four fold reduction in labor costs per insect assayed and reduces reagent costs to $3.81 per pool of 200 flies, or less than $0.02 per insect assayed. Conclusions/Significance The oligonucleotide capture assay represents a substantial improvement in the procedure used to detect parasite prevalence in the vector population, a major metric employed in the process of certifying the elimination of onchocerciasis. PMID:22724041

Flexural properties untreated and treated kenaf fiber reinforced polypropylene composites

NASA Astrophysics Data System (ADS)

Husin, Muhammad Muslimin; Mustapa, Mohammad Sukri; Wahab, Md Saidin; Arifin, Ahmad Mubarak Tajul; Masirin, Mohd Idrus Mohd; Jais, Farhana Hazwanee

2017-05-01

Today natural fiber polymer composites are being extensively used as alternatives in producing furniture to fulfill society demand instead of saving cost and environmentally friendly. The objective of this search is to investigate the untreated fine and rough kenaf fiber (KF) as well as treated KF reinforced with polypropylene (PP) on the flexural strength. Flexural strengths of pure PP, 10%, and 20% of untreated fine and rough KF by weight to PP have been recorded. In addition, flexural strengths of treated KF soaked with 5% and 10% of Sodium Hydroxide (NaOH) have also been recorded. KF reinforced PP (PP/KF) untreated and treated composites were melt blended and then injection molded to observe their flexural strengths by measuring their threshold. Three point bending test was apply to determine the flexural stress of the composites. The result show treated fine KF produce better flexural performance at 20% PP/KF. Scanning Electron Microscopy (SEM) is used to observe the morphological surface PP/KF. Overall 5% NaOH with 20% PP/KF (Fine KF) show good interfacial bonding PP/KF and best result with flexural stress value 30.25MPa.

Comparative study of flexural strength test methods on CAD/CAM Y-TZP dental ceramics

PubMed Central

Xu, Yongxiang; Han, Jianmin; Lin, Hong; An, Linan

2015-01-01

Clinically, fractures are the main cause of computer-aided design and computer-aided manufacturing (CAD/CAM) 3 mol%-yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) all-ceramic dental restorations failure because of repetitive occlusal loading. The goal of this work is to study the effect of test methods and specimen’s size on the flexural strength of five ceramic products. Both bi-axial flexure test (BI) and uni-axial flexure tests (UNI), including three-point flexure test (3PF) and four-point flexure test (4PF), are used in this study. For all five products, the flexural strength is as follows: BI > 3PF > 4PF. Furthermore, specimens with smaller size (3PF-s) have higher values than the bigger ones (3PF). The difference between BI and UNI resulted from the edge flaws in ceramic specimens. The relationship between different UNI (including 3PF-s, 3PF and 4PF) can be explained according to Weibull statistical fracture theory. BI is recommended to evaluate the flexural strength of CAD/CAM Y-TZP dental ceramics. PMID:26816646

Flexural toughness of steel fiber reinforced high performance concrete containing nano-SiO2 and fly ash.

PubMed

Zhang, Peng; Zhao, Ya-Nan; Li, Qing-Fu; Wang, Peng; Zhang, Tian-Hang

2014-01-01

This paper aims to clarify the effect of steel fiber on the flexural toughness of the high performance concrete containing fly ash and nano-SiO2. The flexural toughness was evaluated by two methods, which are based on ASTM C1018 and DBV-1998, respectively. By means of three-point bending method, the flexural toughness indices, variation coefficients of bearing capacity, deformation energy, and equivalent flexural strength of the specimen were measured, respectively, and the relational curves between the vertical load and the midspan deflection (P(V)-δ) were obtained. The results indicate that steel fiber has great effect on the flexural toughness parameters and relational curves (P(V)-δ) of the three-point bending beam specimen. When the content of steel fiber increases from 0.5% to 2%, the flexural toughness parameters increase gradually and the curves are becoming plumper and plumper with the increase of steel fiber content, respectively. However these flexural toughness parameters begin to decrease and the curves become thinner and thinner after the steel fiber content exceeds 2%. It seems that the contribution of steel fiber to the improvement of flexural toughness of the high performance concrete containing fly ash and nano-SiO2 is well performed only when the steel fiber content is less than 2%.

Precision tip-tilt-piston actuator that provides exact constraint

DOEpatents

Hale, Layton C.

1999-01-01

A precision device which can precisely actuate three degrees of freedom of an optic mount, commonly referred to as tip, tilt, and piston. The device consists of three identical flexure mechanisms, an optic mount to be supported and positioned, a structure that supports the flexure mechanisms, and three commercially available linear actuators. The advantages of the precision device is in the arrangement of the constraints offered by the flexure mechanism and not in the particular design of the flexure mechanisms, as other types of mechanisms could be substituted. Each flexure mechanism constrains two degrees of freedom in the plane of the mechanisms and one direction is actuated. All other degrees of freedom are free to move within the range of flexure mechanisms. Typically, three flexure mechanisms are equally spaced in angle about to optic mount and arranged so that each actuated degree of freedom is perpendicular to the plane formed by the optic mount. This arrangement exactly constrains the optic mount and allows arbitrary actuated movement of the plane within the range of the flexure mechanisms. Each flexure mechanism provides a mechanical advantage, typically on the order of 5:1, between the commercially available actuator and the functional point on the optic mount. This improves resolution by the same ratio and stiffness by the square of the ratio.

Flexural properties of polyethylene, glass and carbon fiber-reinforced resin composites for prosthetic frameworks.

PubMed

Maruo, Yukinori; Nishigawa, Goro; Irie, Masao; Yoshihara, Kumiko; Minagi, Shogo

2015-01-01

High flexural properties are needed for fixed partial denture or implant prosthesis to resist susceptibility to failures caused by occlusal overload. The aim of this investigation was to clarify the effects of four different kinds of fibers on the flexural properties of fiber-reinforced composites. Polyethylene fiber, glass fiber and two types of carbon fibers were used for reinforcement. Seven groups of specimens, 2 × 2 × 25 mm, were prepared (n = 10 per group). Four groups of resin composite specimens were reinforced with polyethylene, glass or one type of carbon fiber. The remaining three groups served as controls, with each group comprising one brand of resin composite without any fiber. After 24-h water storage in 37°C distilled water, the flexural properties of each specimen were examined with static three-point flexural test at a crosshead speed of 0.5 mm/min. Compared to the control without any fiber, glass and carbon fibers significantly increased the flexural strength (p < 0.05). On the contrary, the polyethylene fiber decreased the flexural strength (p < 0.05). Among the fibers, carbon fiber exhibited higher flexural strength than glass fiber (p < 0.05). Similar trends were observed for flexural modulus and fracture energy. However, there was no significant difference in fracture energy between carbon and glass fibers (p > 0.05). Fibers could, therefore, improve the flexural properties of resin composite and carbon fibers in longitudinal form yielded the better effects for reinforcement.

Flexural rigidity of the Basin and Range-Colorado Plateau-Rocky Mountain transition from coherence analysis of gravity and topography

NASA Technical Reports Server (NTRS)

Lowery, Anthony R.; Smith, Robert B.

1994-01-01

Stochastic inversion for flexural loads and flexural rigidity of the continental elastic layer can be accomplished most effectively by using the coherence of gravity and topography. However, the spatial resolution of coherence analysis has been limited by use of two-dimensional periodogram spectra from very large (greater than 10(exp 5)sq km) windows that generally include multiple tectonic features. Using a two-dimensional spectral estimator based on the maximum entropy method, the spatial resolution of flexural proerties can be enhanced by a factor of 4 or more, enabling more detailed analysis at the scale of individual tectonic features. This new approach is used to map the spatial variation of flexural rigidity along the Basin and Range transition to the Colorado Plateau and Middle Rocky Mountains physiographic provinces. Large variations in flexural isostatic responses are found, with rigidities ranging from as low as 8.7 x 10(exp 20) N m (elastic thickness (T(sub e) = 4.6 km) in the Basin and Range to as high as 4.1 x 10(exp 24) N m T(sub e) = 77 km) in the Middle Rocky Mountains. These results compare favorably woith independent determinations of flexural rigidity in the region. Areas of low flexural rigidity correlate strongly with areas of high surface heat flow, as is expected from the contingence of flexural rigidity on a temperature-dependent flow law. Also, late Cenozoic normal faults with large displacements are found primarily in area of low flexural rigidity region. The highest flexural rigidity is found within the Archean Wyoming craton, where evidence suggests that deeply rooted cratonic lithosphere may play a role in determining the distribution of tectonism at the surface.

Effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, G.D.; Ho, B.Ping Hsiao; Wallace, J.F.

1993-02-01

The effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates with ply orientation of (0(2),90(2))2S and (90(2),0(2))2S are examined. The relative importance of shear and tensile stresses is examined by varying the span-to-depth ratios of flexural test specimens from 8 to 45. Acoustic emission signals are measured during the flexural tests in order to monitor the initiation and growth of damage. Optical microscopy is used to examine specimens for resin cracking, delamination, and fiber breaks after testing. Transverse matrix cracks and delaminations occur in all specimens, regardless of ply orientation, span-to-depth ratio, or previous exposuremore » of specimens to thermal and mechanical fatigue. A small amount of fiber tensile fracture occurs in the outer 0 deg ply of specimens with high span-to-depth ratios. Because of the complex failure modes, the flexural test results represent the apparent strengths rather than the true flexural or shear strengths for these cross-ply laminates. Thermal cycling of specimens prior to flexural testing does not reduce the apparent flexural strength or change the mode of failure. However, fewer acoustic events are recorded at all strains during flexural testing of specimens exposed to prior thermal cycling. High temperature thermal cycling (32 to 260 C, 100 cycles) causes a greater reduction in acoustic events than low temperature thermal cycling (-85 to +85 C, 500 cycles). Mechanical cycling (0 to 50 percent of the flexural strength, 100 cycles) has a similar effect, except that acoustic events are reduced only at strains less than the maximum strain applied during flexural fatigue.« less

Effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates

NASA Technical Reports Server (NTRS)

Roberts, Gary D.; Ho, Barry Ping Hsiao; Wallace, John F.

1993-01-01

The effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates with ply orientation of (0(2),90(2))2S and (90(2),0(2))2S are examined. The relative importance of shear and tensile stresses is examined by varying the span-to-depth ratios of flexural test specimens from 8 to 45. Acoustic emission signals are measured during the flexural tests in order to monitor the initiation and growth of damage. Optical microscopy is used to examine specimens for resin cracking, delamination, and fiber breaks after testing. Transverse matrix cracks and delaminations occur in all specimens, regardless of ply orientation, span-to-depth ratio, or previous exposure of specimens to thermal and mechanical fatigue. A small amount of fiber tensile fracture occurs in the outer 0 deg ply of specimens with high span-to-depth ratios. Because of the complex failure modes, the flexural test results represent the 'apparent' strengths rather than the true flexural or shear strengths for these cross-ply laminates. Thermal cycling of specimens prior to flexural testing does not reduce the apparent flexural strength or change the mode of failure. However, fewer acoustic events are recorded at all strains during flexural testing of specimens exposed to prior thermal cycling. High temperature thermal cycling (32 to 260 C, 100 cycles) causes a greater reduction in acoustic events than low temperature thermal cycling (-85 to +85 C, 500 cycles). Mechanical cycling (0 to 50 percent of the flexural strength, 100 cycles) has a similar effect, except that acoustic events are reduced only at strains less than the maximum strain applied during flexural fatigue.

The nonlinear flexural response of a whole teleost fish: Contribution of scales and skin.

PubMed

Szewciw, Lawrence; Zhu, Deju; Barthelat, Francois

2017-12-01

The scaled skin of fish is an intricate system that provides mechanical protection against hard and sharp puncture, while maintaining the high flexural compliance required for unhindered locomotion. This unusual combination of local hardness and global compliance makes fish skin an interesting model for bioinspired protective systems. In this work we investigate the flexural response of whole teleost fish, and how scales may affect global flexural stiffness. A bending moment is imposed on the entire body of a striped bass (Morone saxatilis). Imaging is used to measure local curvature, to generate moment-curvature curves as function of position along the entire axis of the fish. We find that the flexural stiffness is the highest in the thick middle portion of the fish, and lowest in the caudal and rostral ends. The flexural response is nonlinear, with an initial soft response followed by significant stiffening at larger flexural deformations. Low flexural stiffness at low curvatures promotes efficient swimming, while higher stiffness at high curvatures enables a possible tendon effect, where the mechanical energy at the end of a stroke is stored in the form of strain energy in the fish skin. To assess the contribution of the scales to stiffening we performed flexural tests with and without scales, following a careful protocol to take in account tissue degradation and the effects of temperature. Our findings suggest that scales do not substantially increase the whole body flexural stiffness of teleost fish over ranges of deformations which are typical of swimming and maneuvering. Teleost scales are thin and relatively flexible, so they can accommodate large flexural deformations. This finding is in contrast to the bulkier ganoid scales which were shown in previous reports to have a profound impact of global flexural deformations and swimming in fish like gar or Polypterus. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evolution of flexural rigidity according to the cross-sectional dimension of a superelastic nickel titanium orthodontic wire.

PubMed

Garrec, Pascal; Tavernier, Bruno; Jordan, Laurence

2005-08-01

The choice of the most suitable orthodontic wire for each stage of treatment requires estimation of the forces generated. In theory, the selection of wire sequences should initially utilize a lower flexural rigidity; thus clinicians use smaller round cross-sectional dimension wires to generate lighter forces during the preliminary alignment stage. This assessment is true for conventional alloys, but not necessarily for superelastic nickel titanium (NiTi). In this case, the flexural rigidity dependence on cross-sectional dimension differs from the linear elasticity prediction because of the martensitic transformation process. It decreases with increasing deflection and this phenomenon is accentuated in the unloading process. This behaviour should lead us to consider differently the biomechanical approach to orthodontic treatment. The present study compared bending in 10 archwires made from NiTi orthodontics alloy of two cross-sectional dimensions. The results were based on microstructural and mechanical investigations. With conventional alloys, the flexural rigidity was constant for each wire and increased largely with the cross-sectional dimension for the same strain. With NiTi alloys, the flexural rigidity is not constant and the influence of size was not as important as it should be. This result can be explained by the non-constant elastic modulus during the martensite transformation process. Thus, in some cases, treatment can begin with full-size (rectangular) wires that nearly fill the bracket slot with a force application deemed to be physiologically desirable for tooth movement and compatible with patient comfort.

A novel vibration assisted polishing device based on the flexural mechanism driven by the piezoelectric actuators

NASA Astrophysics Data System (ADS)

Wang, Guilian; Zhou, Xiaoqin; Ma, Peiqun; Wang, Rongqi; Meng, Guangwei; Yang, Xu

2018-01-01

The vibration assisted polishing has widely application fields because of higher machining frequency and better polishing quality, especially the polishing with the non-resonant mode that is regarded as a kind of promising polishing method. This paper reports a novel vibration assisted polishing device, consisting of the flexible hinge mechanism driven by the piezoelectric actuators, which is suitable for polishing planes or curve surfaces with slow curvature. Firstly, the generation methods of vibration trajectory are investigated for the same frequency and different frequency signals' inputs, respectively, and then the types of elliptic and Lissajous's vibration trajectories are generated respectively. Secondly, a flexural mechanism consisting of the right circular flexible hinges and the leaf springs is developed to produce two-dimensional vibration trajectory. Statics and dynamics investigating of this flexible mechanism are finished in detail. The analytical models about input and output compliances of the flexural mechanism are established according to the matrix-based compliance modeling, and the dynamic model of the flexural mechanism based on the Euler-Lagrange equation is also presented. The finite element model of the flexural mechanism was established to carry out the numerical simulation in order to testify the rationality of device design. Finally, the polishing experiment is carried out to prove the effectiveness of the vibration device. The experimental results show that this novel vibration assisted polishing device developed in this study can remove more effectively the cutting marks left by last process and obviously reduce the workpiece surface roughness.

Compressive and flexural strength of concrete containing palm oil biomass clinker and polypropylene fibres

NASA Astrophysics Data System (ADS)

Ibrahim, M. H. Wan; Mangi, Sajjad Ali; Burhanudin, M. K.; Ridzuan, M. B.; Jamaluddin, N.; Shahidan, S.; Wong, YH; Faisal, SK; Fadzil, M. A.; Ramadhansyah, P. J.; Ayop, S. S.; Othman, N. H.

2017-11-01

This paper presents the effects of using palm oil biomass (POB) clinker with polypropylene (PP) fibres in concrete on its compressive and flexural strength performances. Due to infrastructural development works, the use of concrete in the construction industry has been increased. Simultaneously, it raises the demand natural sand, which causes depletion of natural resources. While considering the environmental and economic benefits, the utilization of industrial waste by-products in concrete will be the alternative solution of the problem. Among the waste products, one of such waste by-product is the palm oil biomass clinker, which is a waste product from burning processes of palm oil fibres. Therefore, it is important to utilize palm oil biomass clinker as partial replacement of fine aggregates in concrete. Considering the facts, an experimental study was conducted to find out the potential usage of palm oil fibres in concrete. In this study, total 48 number of specimens were cast to evaluate the compressive and flexural strength performances. Polypropylene fibre was added in concrete at the rate of 0.2%, 0.4% and 0.6%, and sand was replaced at a constant rate of 10% with palm oil biomass clinker. The flexural strength of concrete was noticed in the range of 2.25 MPa and 2.29 MPa, whereas, the higher value of flexural strength was recorded with 0.4% polypropylene fibre addition. Hence, these results show that the strength performances of concrete containing POB clinker could be improved with the addition of polypropylene fibre.

Reliability Quantification of the Flexure: A Critical Stirling Convertor Component

NASA Technical Reports Server (NTRS)

Shah, Ashwin R.; Korovaichuk, Igor; Zampino, Edward J.

2004-01-01

Uncertainties in the manufacturing, fabrication process, material behavior, loads, and boundary conditions results in the variation of the stresses and strains induced in the flexures and its fatigue life. Past experience and the test data at material coupon levels revealed a significant amount of scatter of the fatigue life. Owing to these facts, the design of the flexure, using conventional approaches based on safety factor or traditional reliability based on similar equipment considerations does not provide a direct measure of reliability. Additionally, it may not be feasible to run actual long term fatigue tests due to cost and time constraints. Therefore it is difficult to ascertain material fatigue strength limit. The objective of the paper is to present a methodology and quantified results of numerical simulation for the reliability of flexures used in the Stirling convertor for their structural performance. The proposed approach is based on application of finite element analysis method in combination with the random fatigue limit model, which includes uncertainties in material fatigue life. Additionally, sensitivity of fatigue life reliability to the design variables is quantified and its use to develop guidelines to improve design, manufacturing, quality control and inspection design process is described.

A combined experimental and finite element study to predict the failure mechanisms in SiC coated carbon/carbon composites at room and elevated temperatures under flexural loading

NASA Technical Reports Server (NTRS)

Mahfuz, Hassan; Das, Partha S.; Xue, Dongwei; Krishnagopalan, Jaya; Jeelani, Shaik

1993-01-01

Response of quasi-isotropic laminates of SiC coated Carbon/Carbon (C/C) composites have been investigated under flexural loading at various temperatures. Variation of load-deflection behavior with temperatures are studied. Increase in flexural strength and stiffness are observed with the rise in temperature. Extensive analyses through Optical Microscope (OM) and Non-Destructive Evaluation (NDE) have been performed to understand the failure mechanisms. Damage zone is found only within the neighborhood of the loading plane. Isoparametric layered shell elements developed on the basis of the first order shear deformation theory have been used to model the thin laminates of C/C under flexural loading. Large deformation behavior has been considered in the finite element analysis to account for the non-linearities encountered during the actual test. Data generated using finite element analysis are presented to corroborate the experimental findings, and a comparison in respect of displacement and stress-strain behavior are given to check the accuracy of the finite element analysis. Reasonable correlation between the experimental and finite element results have been established.

A novel constrained H2 optimization algorithm for mechatronics design in flexure-linked biaxial gantry.

PubMed

Ma, Jun; Chen, Si-Lu; Kamaldin, Nazir; Teo, Chek Sing; Tay, Arthur; Mamun, Abdullah Al; Tan, Kok Kiong

2017-11-01

The biaxial gantry is widely used in many industrial processes that require high precision Cartesian motion. The conventional rigid-link version suffers from breaking down of joints if any de-synchronization between the two carriages occurs. To prevent above potential risk, a flexure-linked biaxial gantry is designed to allow a small rotation angle of the cross-arm. Nevertheless, the chattering of control signals and inappropriate design of the flexure joint will possibly induce resonant modes of the end-effector. Thus, in this work, the design requirements in terms of tracking accuracy, biaxial synchronization, and resonant mode suppression are achieved by integrated optimization of the stiffness of flexures and PID controller parameters for a class of point-to-point reference trajectories with same dynamics but different steps. From here, an H 2 optimization problem with defined constraints is formulated, and an efficient iterative solver is proposed by hybridizing direct computation of constrained projection gradient and line search of optimal step. Comparative experimental results obtained on the testbed are presented to verify the effectiveness of the proposed method. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

An Experimental Study on Strengthening of Reinforced Concrete Flexural Members using Steel Wire Mesh

NASA Astrophysics Data System (ADS)

Al Saadi, Hamza Salim Mohammed; Mohandas, Hoby P.; Namasivayam, Aravind

2017-01-01

One of the major challenges and contemporary research in the field of structural engineering is strengthening of existing structural elements using readily available materials in the market. Several investigations were conducted on strengthening of various structural components using traditional and advanced materials. Many researchers tried to enhance the reinforced concrete (RC) beams strength using steel plate, Glass and Carbon Fibre Reinforced Polymers (GFRP & CFRP). For the reason that high weight to the strength ratio and compatibility in strength between FRP composites and steel bars, steel plates and GFRP and CFRP composites are not used for strengthening works practically. Hence, in this present work the suitability of using wire mesh for the purpose of strengthening the RC flexural members is studied by conducting experimental works. New technique of strengthening system using wire mesh with a view to improve sectional properties and subsequently flexural strength of RC beams is adopted in this work. The results for experimental and theoretical analysis were compared and found that good correlation exists between them. The experimental results indicate that RC beams strengthened with steel wire mesh are easy technique for strengthening of existing flexural members.

Preoperative thoracic radiographic findings in dogs presenting for gastric dilatation-volvulus (2000-2010): 101 cases.

PubMed

Green, Jaime L; Cimino Brown, Dorothy; Agnello, Kimberly A

2012-10-01

To identify the incidence of clinically significant findings on preoperative thoracic radiographs in dogs with gastric dilatation-volvulus (GDV) and to determine if those findings are associated with survival. Retrospective study from 2000 to 2010. Urban university small animal teaching hospital. One hundred and one dogs diagnosed with GDV that had thoracic radiographs obtained preoperatively, and medical records available with the following information available: signalment, time of presentation, respiratory status, plasma lactate, presence of cardiac arrhythmias, reason for thoracic radiographs, radiographic findings, and outcome. None. Findings on preoperative thoracic radiographs included small vena cava (40%), esophageal dilation (39%), microcardia (34%), aspiration pneumonia (14%), cardiomegaly (5%), pulmonary nodule (4%), pulmonary edema (2%), sternal lymphadenopathy (1%), and pulmonary bullae (1%). Eighty-four percent of dogs (85 out of 101) survived to discharge. Dogs without cardiomegaly on presenting thoracic radiographs had a 10.2 greater odds of surviving to discharge. The most common findings on preoperative thoracic radiographs include esophageal dilation, microcardia, and a small vena cava while the incidence of pulmonary nodules was low. A negative association between survival and presence of cardiomegaly on preoperative thoracic radiographs in dogs with GDV supports the need to obtain these images for prognostic information in spite of the emergency surgical nature of the GDV. The main limitations of this study include the possibilities of type I and type II errors, the retrospective nature of the study, and the lack of well-defined criteria for obtaining thoracic radiographs. © Veterinary Emergency and Critical Care Society 2012.

Flexural phonon limited phonon drag thermopower in bilayer graphene

NASA Astrophysics Data System (ADS)

Ansari, Mohd Meenhaz; Ashraf, SSZ

2018-05-01

We investigate the phonon drag thermopower from flexural phonons as a function of electron temperature and carrier concentration in the Bloch-Gruneisen regime in non-strained bilayer graphene using Boltzmann transport equation approach. The flexural phonons are expected to be the major source of intrinsic scattering mechanism in unstrained bilayer graphene due to their large density. The flexural phonon modes dispersion relation is quadratic so these low energy flexural phonons abound at room temperature and as a result deform the bilayer graphene sheet in the out of plane direction and affects the transport properties. We also produce analytical result for phonon-drag thermopower from flexural phonons and find that phonon-drag thermopower depicts T2 dependence on temperature and n-1 on carrier concentration.

Cardiopulmonary measurements in dogs undergoing gastropexy without gastrectomy for correction of gastric dilatation-volvulus.

PubMed

Wagner, A E; Dunlop, C I; Chapman, P L

1999-08-15

To measure cardiopulmonary variables, including cardiac index, in dogs with naturally acquired gastric dilatation-volvulus (GDV). Prospective clinical study. 6 dogs with GDV. In addition to typical medical and surgical management of GDV, the dorsal metatarsal and pulmonary arteries and right atrium of the dogs were catheterized to obtain cardiopulmonary measurements before and during anesthesia and surgery. All dogs underwent gastropexy but none required gastrectomy. Mean cardiac index and mean arterial blood pressure for this small population of dogs with GDV were not significantly different from those reported for clinically normal awake or anesthetized dogs. Dogs with naturally acquired GDV without gastric necrosis may not have the classic characteristics, including decreased cardiac index and hypotension, of hypovolemic circulatory shock.

A prospective study of survival and recurrence following the acute gastric dilatation-volvulus syndrome in 136 dogs.

PubMed

Glickman, L T; Lantz, G C; Schellenberg, D B; Glickman, N W

1998-01-01

Dogs (n = 136) with gastric dilatation-volvulus (GDV) syndrome were followed over time to measure recurrence and mortality rates and to identify prognostic factors. Thirty-three (24.3%) died or were euthanized during the first seven days. Of 85 cases that were followed for up to three years, nine (10.6%) cases each had a recurrence of GDV and seven (8.2%) cases died or were euthanized. The median survival times for cases that had gastropexies and those that did not were 547 and 188 days, respectively. Depressed or comatose cases on admission were three and 36 times, respectively, more likely to die than alert cases, while cases with gastric necrosis were 11 times more likely to die.

Evaluation of lidocaine treatment on frequency of cardiac arrhythmias, acute kidney injury, and hospitalization time in dogs with gastric dilatation volvulus.

PubMed

Bruchim, Yaron; Itay, Srugo; Shira, Ben-Halevy; Kelmer, Efrat; Sigal, Yudelecitch; Itamar, Aroch; Gilad, Segev

2012-08-01

To assess the efficacy of IV lidocaine in decreasing complication rate and improving the outcome in dogs with gastric dilatation volvulus (GDV). Prospective non-controlled study of 83 lidocaine-treated dogs with GDV compared to 47 untreated historical controls with GDV. University veterinary teaching hospital. One hundred and thirty client-owned dogs with naturally occurring GDV. Study group dogs were treated at presentation with lidocaine (2 mg/kg, IV bolus) followed by constant rate infusion (CRI) of 0.05 mg/kg/min for 24 h. Historical control dogs did not receive any lidocaine. There were no group differences in age, body weight, time lag from onset of clinical signs to presentation, rectal temperature and pulse rate at presentation, and proportion of gastric wall necrosis. The proportions of cardiac arrhythmias and acute kidney injury (AKI) were significantly (P< 0.001 and P = 0.045, respectively) lower in the lidocaine group (10/83 [12%] versus 18/47 [38.3%] and 3/83 [3.6] versus 0/47). Median hospitalization time period was shorter (P = 0.05) in the lidocaine group compared to the controls (median 48 h; range 24-360 h versus median 72 h; range 24-144 h, respectively). Early treatment with IV lidocaine bolus, followed by CRI of lidocaine for 24 h post presentation decreased the occurrence of cardiac arrhythmias, AKI and hospitalization time period significantly in lidocaine-treated dogs with GDV compared to untreated historical controls. Due to the nonblinded, placebo-uncontrolled, nonrandomized nature of the current study, further evaluation of the efficacy of lidocaine in dogs with GDV is warranted. © Veterinary Emergency and Critical Care Society 2012.

Filariasis in Travelers Presenting to the GeoSentinel Surveillance Network

PubMed Central

Lipner, Ettie M.; Law, Melissa A.; Barnett, Elizabeth; Keystone, Jay S.; von Sonnenburg, Frank; Loutan, Louis; Prevots, D. Rebecca; Klion, Amy D.; Nutman, Thomas B.

2007-01-01

Background As international travel increases, there is rising exposure to many pathogens not traditionally encountered in the resource-rich countries of the world. Filarial infections, a great problem throughout the tropics and subtropics, are relatively rare among travelers even to filaria-endemic regions of the world. The GeoSentinel Surveillance Network, a global network of medicine/travel clinics, was established in 1995 to detect morbidity trends among travelers. Principal Findings We examined data from the GeoSentinel database to determine demographic and travel characteristics associated with filaria acquisition and to understand the differences in clinical presentation between nonendemic visitors and those born in filaria-endemic regions of the world. Filarial infections comprised 0.62% (n = 271) of all medical conditions reported to the GeoSentinel Network from travelers; 37% of patients were diagnosed with Onchocerca volvulus, 25% were infected with Loa loa, and another 25% were diagnosed with Wuchereria bancrofti. Most infections were reported from immigrants and from those immigrants returning to their county of origin (those visiting friends and relatives); the majority of filarial infections were acquired in sub-Saharan Africa. Among the patients who were natives of filaria-nonendemic regions, 70.6% acquired their filarial infection with exposure greater than 1 month. Moreover, nonendemic visitors to filaria-endemic regions were more likely to present to GeoSentinel sites with clinically symptomatic conditions compared with those who had lifelong exposure. Significance Codifying the filarial infections presenting to the GeoSentinel Surveillance Network has provided insights into the clinical differences seen among filaria-infected expatriates and those from endemic regions and demonstrated that O. volvulus infection can be acquired with short-term travel. PMID:18160987

Effect of etching time and resin bond on the flexural strength of IPS e.max Press glass ceramic.

PubMed

Xiaoping, Luo; Dongfeng, Ren; Silikas, Nick

2014-12-01

To evaluate the effect of hydrofluoric acid (HFA) etching time and resin cement bond on the flexural strength of IPS e.max(®) Press glass ceramic. Two hundred and ten bars, 25mm×3mm×2mm, were made from IPS e.max(®) Press ingots through lost-wax, hot-pressed ceramic fabrication technology and randomly divided into five groups with forty-two per group after polishing. The ceramic surfaces of different groups were etched by 9.5% hydrofluoric acid gel for 0, 20, 40, 60 and 120s respectively. Two specimens of each group were selected randomly to examine the surface roughness and 3-dimensional topography with atomic force microscope (AFM), and microstructure was analyzed by the field emission scanning electron microscope (FE-SEM). Then each group were subdivided into two subgroups (n=20). One subgroup of this material was selected to receive a thin (approximately 0.1mm) layer of resin luting agent (Variolink N) whereas the other subgroup remained unaltered. Half of subgroup's specimens were thermocycled 10,000 times before a 3-point bending test in order to determine the flexural strength. Interface between resin cement and ceramic was examined with field emission scanning electronic microscope. Roughness values increased with increasing etching time. The mean flexural strength values of group 0s, 20s, 40s, 60s and 120s were 384±33, 347±43, 330±53, 327±67 and 317±41MPa respectively. Increasing HF etching times reduced the mean flexural strength (p<0.05). However, the mean flexural strength of each group, except group 0s, increased significantly to 420±31, 435±50, 400±39 and 412±58MPa after the application of dual-curing resin cement. In the present investigation, no significant differences after thermocycling on the flexural strengths were evident. Overtime HF etching could have a wakening effect on IPS e.max(®) Press glass ceramic, but resin cement bonding to appropriately etched surface would strengthen the dental ceramic. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Flexural strengthening of Reinforced Concrete (RC) Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP) Laminates

NASA Astrophysics Data System (ADS)

Aravind, N.; Samanta, Amiya K.; Roy, Dilip Kr. Singha; Thanikal, Joseph V.

2015-01-01

Strengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP) sheets for strengthening Reinforced Concrete (RC) beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC) beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.

A disturbance observer-based adaptive control approach for flexure beam nano manipulators.

PubMed

Zhang, Yangming; Yan, Peng; Zhang, Zhen

2016-01-01

This paper presents a systematic modeling and control methodology for a two-dimensional flexure beam-based servo stage supporting micro/nano manipulations. Compared with conventional mechatronic systems, such systems have major control challenges including cross-axis coupling, dynamical uncertainties, as well as input saturations, which may have adverse effects on system performance unless effectively eliminated. A novel disturbance observer-based adaptive backstepping-like control approach is developed for high precision servo manipulation purposes, which effectively accommodates model uncertainties and coupling dynamics. An auxiliary system is also introduced, on top of the proposed control scheme, to compensate the input saturations. The proposed control architecture is deployed on a customized-designed nano manipulating system featured with a flexure beam structure and voice coil actuators (VCA). Real time experiments on various manipulating tasks, such as trajectory/contour tracking, demonstrate precision errors of less than 1%. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Solution hardened platinum alloy flexure materials for improved performance and reliability of MEMS devices

NASA Astrophysics Data System (ADS)

Brazzle, John D.; Taylor, William P.; Ganesh, Bala; Price, James J.; Bernstein, Jonathan J.

2005-01-01

Solution hardened platinum alloys are presented for use as a MEMS flexure material. Two Pt alloys are discussed in this work; Pt alloyed with 15% Rh and 6% Ru (known as Alloy 851) and an alloy of Pt with 10% Ir. These alloys do not require protective masking, resulting in fewer fabrication steps because the alloys can be exposed to fluorine, chlorine and oxygen plasmas as well as wet chemical etches without damage. These alloys combine many desirable properties such as biocompatibility, extreme corrosion resistance, good electrical/thermal conductivity, high Young's modulus, high yield strength [1], low hysteresis and fatigue, and they are non-ferromagnetic. Compositional profiles for the sputtered films are described, as well as stress control during deposition. Nanoindentation experiments were performed to measure mechanical properties. The mechanical performance of these Pt alloy flexures as supports for rotating micromirror structures is described.

Biobased Epoxy Resins from Deconstructed Native Softwood Lignin.

PubMed

van de Pas, Daniel J; Torr, Kirk M

2017-08-14

The synthesis of novel epoxy resins from lignin hydrogenolysis products is reported. Native lignin in pine wood was depolymerized by mild hydrogenolysis to give an oil product that was reacted with epichlorohydrin to give epoxy prepolymers. These were blended with bisphenol A diglycidyl ether or glycerol diglycidyl ether and cured with diethylenetriamine or isophorone diamine. The key novelty of this work lies in using the inherent properties of the native lignin in preparing new biobased epoxy resins. The lignin-derived epoxy prepolymers could be used to replace 25-75% of the bisphenol A diglycidyl ether equivalent, leading to increases of up to 52% in the flexural modulus and up to 38% in the flexural strength. Improvements in the flexural strength were attributed to the oligomeric products present in the lignin hydrogenolysis oil. These results indicate lignin hydrogenolysis products have potential as sustainable biobased polyols in the synthesis of high performance epoxy resins.

Systemic drug-related intertriginous and flexural exanthema (SDRIFE).

PubMed

Elmariah, Sarina B; Cheung, Wang; Wang, Nadia; Kamino, Hideko; Pomeranz, Miriam K

2009-08-15

A 72-year-old man with a history of metastatic melanoma presented with a two-day history of erythematous and edematous plaques, with scattered bullae on the neck, chest, axillae, and inguinal and gluteal folds, which began five days after infusion of an experimental drug. The clinical and histopathologic findings were consistent with systemic drug-related intertriginous and flexural exanthema (SDRIFE), which is an uncommon drug reaction that results in symmetric erythema that affects the buttocks, groin, and/or thighs as well other flexural folds. The clinical manifestations of SDRIFE are highly characteristic and include distinctive primary cutaneous lesions with a specific distribution and course; however, heterogeneity exists with respect to histopathologic features, skin test results, and in vitro investigations. The exact mechanism of SDRIFE remains unknown but is thought to result from a type IV delayed hypersensitivity immune response. Treatment is symptomatic and includes topical or oral glucocorticoids.

Acoustically Generated Flows in Flexural Plate Wave Sensors: a Multifield Analysis

NASA Astrophysics Data System (ADS)

Sayar, Ersin; Farouk, Bakhtier

2011-11-01

Acoustically excited flows in a microchannel flexural plate wave device are explored numerically with a coupled solid-fluid mechanics model. The device can be exploited to integrate micropumps with microfluidic chips. A comprehensive understanding of the device requires the development of coupled two or three-dimensional fluid structure interactive (FSI) models. The channel walls are composed of layers of ZnO, Si3N4 and Al. An isothermal equation of state for the fluid (water) is employed. The flexural motions of the channel walls and the resulting flowfields are solved simultaneously. A parametric analysis is performed by varying the values of the driving frequency, voltage of the electrical signal and the channel height. The time averaged axial velocity is found to be proportional to the square of the wave amplitude. The present approach is superior to the method of successive approximations where the solid-liquid coupling is weak.

Thermal and mechanical behaviour of sub micron sized fly ash reinforced polyester resin composite

NASA Astrophysics Data System (ADS)

Nantha Kumar, P.; Rajadurai, A.; Muthuramalingam, T.

2018-04-01

The utilization of particles reinforced resin matrix composites is being increased owing to its lower density and high strength to weight ratio. In the present study, an attempt has been made to synthesize fly ash particles reinforced polyester resin composite for engine cowling application. The thermal stability and mechanical behaviours such as hardness and flexural strength of the composite with 2, 3 and 4 weight % of reinforcement is studied and analyzed. The thermo gravimetric analysis indicates that the higher addition of reinforcement increases the decomposition temperature due to its refractory nature. It is also observed that the hardness increases with higher filler addition owing to the resistance of FA particles towards penetration. The flexural strength is found to increase up to the addition of 3% of FA particles, whereas the polyester resin composite prepared with 4% FA particles addition is observed to have low flexural strength owing to agglomeration of particles.

The impact of hydrofluoric acid etching followed by unfilled resin on the biaxial strength of a glass-ceramic.

PubMed

Posritong, Sumana; Borges, Alexandre Luiz Souto; Chu, Tien-Min Gabriel; Eckert, George J; Bottino, Marco A; Bottino, Marco C

2013-11-01

To evaluate the null hypotheses that hydrofluoric (HF) acid etching time would neither decrease the biaxial flexural strength of a glass-based veneering ceramic nor enhance it after silane and unfilled resin (UR) applications. Disc-shaped IPS e.max ZirPress specimens were allocated into 12 groups: G1-control (no-etching), G2-30 s, G3-60 s, G4-90 s, G5-120 s, G6-60 s+60 s. Groups (G7-G12) were treated in the same fashion as G1-G6, but followed by silane and UR applications. Surface morphology and roughness (Ra and Rq) of the ceramics were assessed by means of scanning electron microscopy (SEM) and profilometry, respectively. Flexural strength was determined by biaxial testing. Data were analyzed by two-way ANOVA and the Sidak test (α=0.05). Weibull statistics were estimated and finite element analysis (FEA) was carried out to verify the stress concentration end areas of fracture. The interaction (etching time vs. surface treatment) was significant for Ra (p=0.008) and Rq (0.0075). Resin-treated groups presented significantly lower Ra and Rq than non-treated groups, except for the 60s group (p<0.005). SEM revealed that etching affected the ceramic microstructure and that the UR was able to penetrate into the irregularities. A significant effect of etching time (p=0.029) on flexural strength was seen. G7-G12 presented higher strength than G1-G6 (p<0.0001). None of experimental groups failed to show 95% confidence intervals of σ0 and m overlapped. FEA showed lower stress concentration after resin treatment. HF acid etching time did not show a damaging effect on the ceramic flexural strength. Moreover, the flexural strength could be enhanced after UR treatment. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

The flexural properties of endodontic post materials.

PubMed

Stewardson, Dominic A; Shortall, Adrian C; Marquis, Peter M; Lumley, Philip J

2010-08-01

To measure the flexural strengths and moduli of endodontic post materials and to assess the effect on the calculated flexural properties of varying the diameter/length (D/L) ratio of three-point bend test samples. Three-point bend testing of samples of 2mm diameter metal and fiber-reinforced composite (FRC) rods was carried out and the mechanical properties calculated at support widths of 16 mm, 32 mm and 64 mm. Weibull analysis was performed on the strength data. The flexural strengths of all the FRC post materials exceeded the yield strengths of the gold and stainless steel samples; the flexural strengths of two FRC materials were comparable with the yield strength of titanium. Stainless steel recorded the highest flexural modulus while the titanium and the two carbon fiber materials exhibited similar values just exceeding that of gold. The remaining glass fiber materials were of lower modulus within the range of 41-57 GPa. Weibull modulus values for the FRC materials ranged from 16.77 to 30.09. Decreasing the L/D ratio produced a marked decrease in flexural modulus for all materials. The flexural strengths of FRC endodontic post materials as new generally exceed the yield strengths of metals from which endodontic posts are made. The high Weibull modulus values suggest good clinical reliability of FRC posts. The flexural modulus values of the tested posts were from 2-6 times (FRC) to 4-10 times (metal) that of dentin. Valid measurement of flexural properties of endodontic post materials requires that test samples have appropriate L/D ratios. Copyright 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Nonlinear mode interaction in equal-leg angle struts susceptible to cellular buckling.

PubMed

Bai, L; Wang, F; Wadee, M A; Yang, J

2017-11-01

A variational model that describes the interactive buckling of a thin-walled equal-leg angle strut under pure axial compression is presented. A formulation combining the Rayleigh-Ritz method and continuous displacement functions is used to derive a system of differential and integral equilibrium equations for the structural component. Solving the equations using numerical continuation reveals progressive cellular buckling (or snaking) arising from the nonlinear interaction between the weak-axis flexural buckling mode and the strong-axis flexural-torsional buckling mode for the first time-the resulting behaviour being highly unstable. Physical experiments conducted on 10 cold-formed steel specimens are presented and the results show good agreement with the variational model.

Flexural Toughness of Steel Fiber Reinforced High Performance Concrete Containing Nano-SiO2 and Fly Ash

PubMed Central

Zhao, Ya-Nan; Li, Qing-Fu; Wang, Peng; Zhang, Tian-Hang

2014-01-01

This paper aims to clarify the effect of steel fiber on the flexural toughness of the high performance concrete containing fly ash and nano-SiO2. The flexural toughness was evaluated by two methods, which are based on ASTM C1018 and DBV-1998, respectively. By means of three-point bending method, the flexural toughness indices, variation coefficients of bearing capacity, deformation energy, and equivalent flexural strength of the specimen were measured, respectively, and the relational curves between the vertical load and the midspan deflection (P V-δ) were obtained. The results indicate that steel fiber has great effect on the flexural toughness parameters and relational curves (P V-δ) of the three-point bending beam specimen. When the content of steel fiber increases from 0.5% to 2%, the flexural toughness parameters increase gradually and the curves are becoming plumper and plumper with the increase of steel fiber content, respectively. However these flexural toughness parameters begin to decrease and the curves become thinner and thinner after the steel fiber content exceeds 2%. It seems that the contribution of steel fiber to the improvement of flexural toughness of the high performance concrete containing fly ash and nano-SiO2 is well performed only when the steel fiber content is less than 2%. PMID:24883395

Experimental investigation on flexure and impact properties of injection molded polypropylene-nylon 6-glass fiber polymer composites

NASA Astrophysics Data System (ADS)

Nuruzzaman, D. M.; Kusaseh, N. M.; Chowdhury, M. A.; Rahman, N. A. N. A.; Oumer, A. N.; Fatchurrohman, N.; Iqbal, A. K. M. A.; Ismail, N. M.

2018-04-01

In this research study, glass fiber (GF) reinforced polypropylene (PP)-nylon 6 (PA6) polymer blend composites were prepared using injection molding process. Specimens of four different compositions such as 80%PP+20%PA6, 80%PP+18%PA6+2%GF, 80%PP+16%PA6+4%GF and 80%PP+14%PA6+6%GF were prepared. In the injection molding process, suitable process parameters were selected depending on the type of composite specimen in producing defects free dog bone shaped specimens. Flexure and impact tests were carried out according to ASTM standard. The important flexure properties such as flexural modulus, flexural yield strength, flexural strength and flexural strain were investigated. The obtained results revealed that flexural modulus of 80%PP+20%PA6 polymer blend is the lowest and the polymer blend composite shows steadily improved modulus as the glass fiber content is increased. Results also showed that flexural strength of pure polymer blend is the lowest but it improves gradually when the glass fiber content is increased. Impact test results revealed that impact strength of 80%PP+20%PA6 polymer blend is the highest whereas all the composites show reduced impact strength or toughness. It is noticed that 80%PP+14%PA6+6%GF composite exhibits the lowest impact strength.

Volvulus - childhood

MedlinePlus

... away if this happens. Alternative Names Childhood ... In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; 2016:chap 330. ...

Laboratory and environmental decay of wood–plastic composite boards: flexural properties

Treesearch

Rebecca Ibach; Marek Gnatowski; Grace Sun; Jessie Glaeser; Mathew Leung; John Haight

2017-01-01

The flexural properties of wood–plastic composite (WPC) deck boards exposed to 9.5 years of environmental decay in Hilo, Hawaii, were compared to samples exposed to moisture and decay fungi for 12 weeks in the laboratory, to establish a correlation between sample flexural properties and calculated void volume. Specimens were tested for flexural strength and modulus,...

Mechanical properties of resin cements with different activation modes.

PubMed

Braga, R R; Cesar, P F; Gonzaga, C C

2002-03-01

Dual-cured cements have been studied in terms of the hardness or degree of conversion achieved with different curing modes. However, little emphasis is given to the influence of the curing method on other mechanical properties. This study investigated the flexural strength, flexural modulus and hardness of four proprietary resin cements. Materials tested were: Enforce and Variolink II (light-, self- and dual-cured), RelyX ARC (self- and dual-cured) and C & B (self-cured). Specimens were fractured using a three-point bending test. Pre-failure loads corresponding to specific displacements of the cross-head were used for flexural modulus calculation. Knoop hardness (KHN) was measured on fragments obtained after the flexural test. Tests were performed after 24 h storage at 37 degrees C. RelyX ARC dual-cured showed higher flexural strength than the other groups. RelyX ARC and Variolink II depended upon photo-activation to achieve higher hardness values. Enforce showed similar hardness for dual- and self-curing modes. No correlation was found between flexural strength and hardness, indicating that other factors besides the degree of cure (e.g. filler content and monomer type) affect the flexural strength of composites. No statistical difference was detected in the flexural modulus among the different groups.

Improved Strength and Toughness of Carbon Woven Fabric Composites with Functionalized MWCNTs

PubMed Central

Soliman, Eslam; Kandil, Usama; Reda Taha, Mahmoud

2014-01-01

This investigation examines the role of carboxyl functionalized multi-walled carbon nanotubes (COOH-MWCNTs) in the on- and off-axis flexure and the shear responses of thin carbon woven fabric composite plates. The chemically functionalized COOH-MWCNTs were used to fabricate epoxy nanocomposites and, subsequently, carbon woven fabric plates to be tested on flexure and shear. In addition to the neat epoxy, three loadings of COOH-MWCNTs were examined: 0.5 wt%, 1.0 wt% and 1.5 wt% of epoxy. While no significant statistical difference in the flexure response of the on-axis specimens was observed, significant increases in the flexure strength, modulus and toughness of the off-axis specimens were observed. The average increase in flexure strength and flexure modulus with the addition of 1.5 wt% COOH-MWCNTs improved by 28% and 19%, respectively. Finite element modeling is used to demonstrate fiber domination in on-axis flexure behavior and matrix domination in off-axis flexure behavior. Furthermore, the 1.5 wt% COOH-MWCNTs increased the toughness of carbon woven composites tested on shear by 33%. Microstructural investigation using Fourier Transform Infrared Spectroscopy (FTIR) proves the existence of chemical bonds between the COOH-MWCNTs and the epoxy matrix. PMID:28788698

Slow Crack Growth Behavior and Life/Reliability Analysis of 96 wt % Alumina at Ambient Temperature With Various Specimen/Loading Configurations

NASA Technical Reports Server (NTRS)

Choi, Sung R.; Powers, Lynn M.; Nemeth, Noel N.

2000-01-01

Extensive constant stress-rate testing for 96 wt % alumina was conducted in room-temperature distilled water using four different specimen/loading configurations: rectangular beam test specimens under four-point uniaxial flexure, square plate test specimens in ring-on-ring biaxial flexure, square plate test specimens in ball-on-ring biaxial flexure, and dog-boned tensile test specimens in pure tension. The slow crack growth (SCG) parameter n was almost independent of specimen/loading configurations, in either four-point uniaxial flexure, ring-on-ring biaxial flexure, ball-on-ring biaxial flexure, or pure tension, ranging from n = 35 to 47 with an average value of n = 41.1 +/- 4.5. The prediction of fatigue strength/reliability based on the four-point uniaxial flexure data by using the CARES/Life design code as well as a simple PIA model was in good agreement with both the ring-on-ring biaxial and the ball-on-ring biaxial flexure data. A poor prediction using the PIA model was observed for the dog-boned tensile test specimens, presumably due to different flaw population involved in the tensile test specimens.

Cymatics for the cloaking of flexural vibrations in a structured plate

PubMed Central

Misseroni, D.; Colquitt, D. J.; Movchan, A. B.; Movchan, N. V.; Jones, I. S.

2016-01-01

Based on rigorous theoretical findings, we present a proof-of-concept design for a structured square cloak enclosing a void in an elastic lattice. We implement high-precision fabrication and experimental testing of an elastic invisibility cloak for flexural waves in a mechanical lattice. This is accompanied by verifications and numerical modelling performed through finite element simulations. The primary advantage of our square lattice cloak, over other designs, is the straightforward implementation and the ease of construction. The elastic lattice cloak, implemented experimentally, shows high efficiency. PMID:27068339

Duodenal lengthening in an adult with ultra-short bowel syndrome. A case report.

PubMed

Bueno, Javier; Burgos, Rosa; Redecillas, Susana; López, Manuel; Balsells, Joaquin

2018-01-01

We have recently demonstrated the feasibility of lengthening the duodenum in children with short bowel syndrome and a dilated duodenum. This procedure gains additional intestinal length in a challenging area of autologous gut reconstruction. Herein, we report the successful application of this technique in an adult with ultra-short bowel syndrome. A 25-year-old man with a history of mid-gut volvulus was referred to our center for intestinal transplant evaluation. Only a megaduodenum stump that reached as far as the third portion (30 cm of length) and the colon up to the hepatic flexure in the form of a mucous fistula was retained. A gastrostomy tube drained gastric and bilio-pancreatic secretions (output range: 2.5-4 liters/day). The time spent on parenteral nutrition (3 liters/day; 1500 calories/day) and I.V. fluid (1.5-2 liters/day) administration was 24 hours per day. The patient underwent duodenal lengthening and tapering with 7 sequential transverse applications (5 of 45 mm and 2 of 60 mm) of an endoscopic stapler on the anterior and posterior walls of the duodenum, respecting the pancreatic parenchyma and end-to-side duodeno-colonic anastomosis. The final duodenal length was 83 cm. The pre-lengthening citrulline level increased from 13.6 micromol/L to 21.6 micromol/L one year post-lengthening. After 24 month of follow-up, the time on a parenteral pump was shortened to 9 hours during the night. The volume and calorie requirements were also reduced by half. Duodenal lengthening may be effective as part of the autologous intestinal reconstruction armamentarium in adults with short bowel syndrome.

Comparison of the recurrence rate of gastric dilatation with or without volvulus in dogs after circumcostal gastropexy versus gastrocolopexy.

PubMed

Eggertsdóttir, A V; Stigen y, Ø; Lønaas, L; Langeland, M; Devor, M; Vibe-Petersen, G; Eriksen, T

2001-01-01

To compare the recurrence rate of acute gastric dilatation with or without volvulus (GDV) after circumcostal gastropexy (CCGP) or gastrocolopexy (GCP) in dogs. A prospective, double-blind, multicenter, randomized, controlled, clinical trial with two groups (A and B). Fifty-four client-owned dogs presented for treatment of GDV. Dogs with acute GDV that had not previously had a gastropexy performed were included. The preoperative treatment before gastropexy was standardized. A CCGP was performed on dogs in group A, and a GCP was performed on dogs in group B. Postoperative treatment was standardized, but deviation did occur according to the special needs of particular patients. A minimal follow-up time of 180 days was required for dogs not excluded from the study. The median follow-up time in group A was 700 days; in group B, it was 400 days. The occurrence of abdominal pain and gastrointestinal problems after surgery were recorded by the owners. There was no significant difference in the recurrence rate of GDV between the two groups. At the end of the study, the recurrence rate was 9% and 20% in group A and in group B, respectively. Both surgical techniques are effective in preventing recurrence of GDV. Copyright 2001 by The American College of Veterinary Surgeons

Vaccines to combat river blindness: expression, selection and formulation of vaccines against infection with Onchocerca volvulus in a mouse model

PubMed Central

Hess, Jessica A.; Zhan, Bin; Bonne-Année, Sandra; Deckman, Jessica M.; Bottazzi, Maria Elena; Hotez, Peter J.; Klei, Thomas R.; Lustigman, Sara; Abraham, David

2014-01-01

Human onchocerciasis is a neglected tropical disease caused by Onchocerca volvulus and an important cause of blindness and chronic disability in the developing world. Although mass drug administration of ivermectin has had a profound effect on control of the disease, additional tools are critically needed including the need for a vaccine against onchocerciasis. The objectives of the present study were to: (i) select antigens with known vaccine pedigrees as components of a vaccine; (ii) produce the selected vaccine antigens under controlled conditions, using two expression systems and in one laboratory and (iii) evaluate their vaccine efficacy using a single immunization protocol in mice. In addition, we tested the hypothesis that joining protective antigens as a fusion protein or in combination, into a multivalent vaccine, would improve the ability of the vaccine to induce protective immunity. Out of eight vaccine candidates tested in this study, Ov-103, Ov-RAL-2 and Ov-CPI-2M were shown to reproducibly induce protective immunity when administered individually, as fusion proteins or in combination. Although there was no increase in the level of protective immunity induced by combining the antigens into one vaccine, these antigens remain strong candidates for inclusion in a vaccine to control onchocerciasis in humans. PMID:24907553

Introduction to TAFI - A Matlab® toolbox for analysis of flexural isostasy

NASA Astrophysics Data System (ADS)

Jha, S.; Harry, D. L.; Schutt, D.

2016-12-01

The isostatic response of vertical tectonic loads emplaced on thin elastic plates overlying inviscid substrate and the corresponding gravity anomalies are commonly modeled using well established theories and methodologies of flexural analysis. However, such analysis requires some mathematical and coding expertise on part of users. With that in mind, we designed a new interactive Matlab® toolbox called Toolbox for Analysis of Flexural Isostasy (TAFI). TAFI allows users to create forward models (2-D and 3-D) of flexural deformation of the lithosphere and resulting gravity anomaly. TAFI computes Green's Functions for flexure of the elastic plate subjected to point or line loads, and analytical solution for harmonic loads. Flexure due to non-impulsive, distributed 2-D or 3-D loads are computed by convolving the appropriate Green's function with a user-supplied spatially discretized load function. The gravity anomaly associated with each density interface is calculated by using the Fourier Transform of flexural deflection of these interfaces and estimating the gravity in the wavenumber domain. All models created in TAFI are based on Matlab's intrinsic functions and do not require any specialized toolbox, function or library except those distributed with TAFI. Modeling functions within TAFI can be called from Matlab workspace, from within user written programs or from the TAFI's graphical user interface (GUI). The GUI enables the user to model the flexural deflection of lithosphere interactively, enabling real time comparison of model fit with observed data constraining the flexural deformation and gravity, facilitating rapid search for best fitting flexural model. TAFI is a very useful teaching and research tool and have been tested rigorously in graduate level teaching and basic research environment.

The effect on the flexural strength, flexural modulus and compressive strength of fibre reinforced acrylic with that of plain unfilled acrylic resin - an in vitro study.

PubMed

Thomas, Tony C; K, Aswini Kumar; Mohamed, Shamaz; Krishnan, Vinod; Mathew, Anil; V, Manju

2015-03-01

The aim of this in vitro study was to compare the flexural strength, the flexural modulus and compressive strength of the acrylic polymer reinforced with glass, carbon, polyethylene and Kevlar fibres with that of plain unfilled resin. A total of 50 specimens were prepared and divided into 10 specimens each under 5 groups namely group 1- control group without any fibres, group 2 - carbon fibres, group 3- glass fibres, group 4 - polyethylene, group 5- Kevlar. Universal testing machine (Tinius olsen, USA) was used for the testing of these specimens. Out of each group, 5 specimens were randomly selected and testing was done for flexural strength using a three point deflection test and three point bending test for compressive strength and the modulus was plotted using a graphical method. Statistical analysis was done using statistical software. The respective mean values for samples in regard to their flexural strength for PMMA plain, PMMA+ glass fibre, PMMA+ carbon, PMMA+ polyethylene and PMMA+ Kevlar were 90.64, 100.79, 102.58, 94.13 and 96.43 respectively. Scheffes post hoc test clearly indicated that only mean flexural strength values of PMMA + Carbon, has the highest mean value. One-way ANOVA revealed a non-significant difference among the groups in regard to their compressive strength. The study concludes that carbon fibre reinforced samples has the greatest flexural strength and greatest flexural modulus, however the compressive strength remains unchanged.

Monolithic Flexure Pre-Stressed Ultrasonic Horns

NASA Technical Reports Server (NTRS)

Sherrit, Stewart; Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph; Allen, Phillip Grant

2011-01-01

High-power ultrasonic actuators are generally assembled with a horn, backing, stress bolt, piezoelectric rings, and electrodes. The manufacturing process is complex, expensive, difficult, and time-consuming. The internal stress bolt needs to be insulated and presents a potential internal discharge point, which can decrease actuator life. Also, the introduction of a center hole for the bolt causes many failures, reducing the throughput of the manufactured actuators. A new design has been developed for producing ultrasonic horn actuators. This design consists of using flexures rather than stress bolts, allowing one to apply pre-load to the piezoelectric material. It also allows one to manufacture them from a single material/plate, rapid prototype them, or make an array in a plate or 3D structure. The actuator is easily assembled, and application of pre-stress greater than 25 MPa was demonstrated. The horn consists of external flexures that eliminate the need for the conventional stress bolt internal to the piezoelectric, and reduces the related complexity. The stress bolts are required in existing horns to provide prestress on piezoelectric stacks when driven at high power levels. In addition, the manufacturing process benefits from the amenability to produce horn structures with internal cavities. The removal of the pre-stress bolt removes a potential internal electric discharge point in the actuator. In addition, it significantly reduces the chances of mechanical failure in the piezoelectric stacks that result from the hole surface in conventional piezoelectric actuators. The novel features of this disclosure are: 1. A design that can be manufactured from a single piece of metal using EDM, precision machining, or rapid prototyping. 2. Increased electromechanical coupling of the horn actuator. 3. Higher energy density. 4. A monolithic structure of a horn that consists of an external flexure or flexures that can be used to pre-stress a solid piezoelectric structure rather than a bolt, which requires a through hole in the piezoelectric material. 5. A flexure system with low stiffness that accommodates mechanical creep with minor reduction in pre-stress.

Preparation, mechanical, and in vitro properties of glass fiber-reinforced polycarbonate composites for orthodontic application.

PubMed

Tanimoto, Yasuhiro; Inami, Toshihiro; Yamaguchi, Masaru; Nishiyama, Norihiro; Kasai, Kazutaka

2015-05-01

Generally, orthodontic treatment uses metallic wires made from stainless steel, cobalt-chromium-nickel alloy, β-titanium alloy, and nickel-titanium (Ni-Ti) alloy. However, these wires are not esthetically pleasing and may induce allergic or toxic reactions. To correct these issues, in the present study we developed glass-fiber-reinforced plastic (GFRP) orthodontic wires made from polycarbonate and E-glass fiber by using pultrusion. After fabricating these GFRP round wires with a diameter of 0.45 mm (0.018 inch), we examined their mechanical and in vitro properties. To investigate how the glass-fiber diameter affected their physical properties, we prepared GFRP wires of varying diameters (7 and 13 µm). Both the GFRP with 13-µm fibers (GFRP-13) and GFRP with 7 µm fibers (GFRP-7) were more transparent than the metallic orthodontic wires. Flexural strengths of GFRP-13 and GFRP-7 were 690.3 ± 99.2 and 938.1 ± 95.0 MPa, respectively; flexural moduli of GFRP-13 and GFRP-7 were 25.4 ± 4.9 and 34.7 ± 7.7 GPa, respectively. These flexural properties of the GFRP wires were nearly equivalent to those of available Ni-Ti wires. GFRP-7 had better flexural properties than GFRP-13, indicating that the flexural properties of GFRP increase with decreasing fiber diameter. Using thermocycling, we found no significant change in the flexural properties of the GFRPs after 600 or 1,200 cycles. Using a cytotoxicity detection kit, we found that the glass fiber and polycarbonate components comprising the GFRP were not cytotoxic within the limitations of this study. We expect this metal-free GFRP wire composed of polycarbonate and glass fiber to be useful as an esthetically pleasing alternative to current metallic orthodontic wire. © 2014 Wiley Periodicals, Inc.

Optimal design of a Φ760 mm lightweight SiC mirror and the flexural mount for a space telescope

NASA Astrophysics Data System (ADS)

Li, Zongxuan; Chen, Xue; Wang, Shaoju; Jin, Guang

2017-12-01

A flexural support technique for lightweighted Primary Mirror Assembly (PMA) of a space telescope is presented in this article. The proposed three-point flexural mount based on a cartwheel flexure can maintain the surface figure of the PMA in a horizontal optical testing layout. The on-orbit surface error of the PMA causes significant degradation in image quality. On-ground optical testing cannot determine the zero-gravity figure of the PMA due to surface distortion by gravity. We unveiled the crucial fact that through a delicate mounting structure design, the surface figure can remain constant precisely without inducing distinguishable astigmatism when PMA rotates with respect to the optical axis, and the figure can be considered as the zero-gravity surface figure on the orbit. A design case is described to show the lightweight design of a SiC mirror and the optimal flexural mounting. Topology optimization and integrated opto-mechanical analysis using the finite element method are utilized in the design process. The Primary Mirror and mounting structures were fabricated and assembled. After the PMA mirror surface was polished to λ/50 RMS, optical testing in different clocking configurations was performed, respectively, through rotating the PMA by multiple angles. Test results show that the surface figure remained invariant, indicating that gravity release on the orbit will not cause an additional surface error. Vibration tests including sweep sine and random vibration were also performed to validate the mechanical design. The requirements for the mounting technique in space were qualified.

Flexural Plate Wave Devices for Chemical Analysis

DTIC Science & Technology

1991-04-16

Naval Research Laboratory Washi..gton. DC 20375-5000 NRL Memorandum Report 6815 AD-A234 129 Flexural Plate Wave Devices for Chemical Analysis JAY W...4. TITLE AND SUBTITLE S. FUNDING NUMBERS Flexural Plate Wave Devices for Chemical Analysis 6. AUTHOR(S) 61-1638-01 Jay W. Grate. Stuart W. Wenzel... ANALYSIS INTRODUCTION Flexural plate wave (FPW) devices offer many attractive features for chemical analysis (1-9). As gravimetric sensors for chemical

Mechanical properties of kenaf composites using dynamic mechanical analysis

NASA Astrophysics Data System (ADS)

Loveless, Thomas A.

Natural fibers show potential to replace glass fibers in thermoset and thermoplastic composites. Kenaf is a bast-type fiber with high specific strength and great potential to compete with glass fibers. In this research kenaf/epoxy composites were analyzed using Dynamic Mechanical Analysis (DMA). A three-point bend apparatus was used in the DMA testing. The samples were tested at 1 hertz, at a displacement of 10 ?m, and at room temperature. The fiber volume content of the kenaf was varied from 20% - 40% in 5% increments. Ten samples of each fiber volume fraction were manufactured and tested. The flexural storage modulus, the flexural loss modulus, and the loss factor were reported. Generally as the fiber volume fraction of kenaf increased, the flexural storage and flexural loss modulus increased. The loss factor remained relatively constant with increasing fiber volume fraction. Woven and chopped fiberglass/epoxy composites were manufactured and tested to be compared with the kenaf/epoxy composites. Both of the fiberglass/epoxy composites reported higher flexural storage and flexural loss modulus values. The kenaf/epoxy composites reported higher loss factor values. The specific flexural storage and specific flexural loss modulus were calculated for both the fiberglass and kenaf fiber composites. Even though the kenaf composites reported a lower density, the fiberglass composites reported higher specific mechanical properties.

Femoral hernia repair

MedlinePlus

Dunbar KB, Jeyarajah DR. Abdominal hernias and gastric volvulus. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease . 10th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap ...

[Our current approach in the treatment of sigmoid colon volvulus].

PubMed

Taviloğlu, Korhan; Aydin, Erol; Ertekin, Cemalettin; Güloğlu, Recep; Kurtoğlu, Mehmet

2002-04-01

Our aim was to emphasize the role of endoscopic detorsion in the treatment of sigmoid colon volvulus, which we currently apply in the majority of our cases. The data of 37 patients were analyzed in a retrospective manner, during a 86-month period, between May 1994 and July 2001. The patients were classified into three groups. The first group consisted of 9 patients with resection and anastomosis, the second group consisted of 20 patients with Hartmann's procedure, and the third group consisted of 8 patients with endoscopic detorsion. Complications were encountered in 7 patients (19%), and 3 patients (8%) died following treatment. We favor colonic resection following endoscopic treatment. Resection should be preferred, if endoscopic detorsion is not successful or in the presence of a complication.

Experimental Evaluation of Three Designs of Electrodynamic Flexural Transducers

PubMed Central

Eriksson, Tobias J. R.; Laws, Michael; Kang, Lei; Fan, Yichao; Ramadas, Sivaram N.; Dixon, Steve

2016-01-01

Three designs for electrodynamic flexural transducers (EDFT) for air-coupled ultrasonics are presented and compared. An all-metal housing was used for robustness, which makes the designs more suitable for industrial applications. The housing is designed such that there is a thin metal plate at the front, with a fundamental flexural vibration mode at ∼50 kHz. By using a flexural resonance mode, good coupling to the load medium was achieved without the use of matching layers. The front radiating plate is actuated electrodynamically by a spiral coil inside the transducer, which produces an induced magnetic field when an AC current is applied to it. The transducers operate without the use of piezoelectric materials, which can simplify manufacturing and prolong the lifetime of the transducers, as well as open up possibilities for high-temperature applications. The results show that different designs perform best for the generation and reception of ultrasound. All three designs produced large acoustic pressure outputs, with a recorded sound pressure level (SPL) above 120 dB at a 40 cm distance from the highest output transducer. The sensitivity of the transducers was low, however, with single shot signal-to-noise ratio (SNR)≃15 dB in transmit–receive mode, with transmitter and receiver 40 cm apart. PMID:27571075

Exact analytical solution of shear-induced flexural vibration of functionally graded piezoelectric beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Pankaj, E-mail: psharma@rtu.ac.in; Parashar, Sandeep Kumar, E-mail: parashar2@yahoo.com

The priority of this paper is to obtain the exact analytical solution for free flexural vibration of FGPM beam actuated using the d{sub 15} effect. In piezoelectric actuators, the potential use of d{sub 15} effect has been of particular interest for engineering applications since shear piezoelectric coefficient d15 is much higher than the other piezoelectric coupling constants d{sub 31} and d{sub 33}. The applications of shear actuators are to induce and control the flexural vibrations of beams and plates. In this study, a modified Timoshenko beam theory is used where electric potential is assumed to vary sinusoidaly along the thicknessmore » direction. The material properties are assumed to be graded across the thickness in accordance with power law distribution. Hamilton's principle is employed to obtain the equations of motion along with the associated boundary conditions for FGPM beams. Exact analytical solution is derived thus obtained equations of motion. Results for clamped-clamped and clamped-free boundary conditions are presented. The presented result and method shell serve as benchmark for comparing the results obtained from the other approximate methods.« less

The Dynamic Performance of Flexural Ultrasonic Transducers.

PubMed

Feeney, Andrew; Kang, Lei; Rowlands, George; Dixon, Steve

2018-01-18

Flexural ultrasonic transducers are principally used as proximity sensors and for industrial metrology. Their operation relies on a piezoelectric ceramic to generate a flexing of a metallic membrane, which delivers the ultrasound signal. The performance of flexural ultrasonic transducers has been largely limited to excitation through a short voltage burst signal at a designated mechanical resonance frequency. However, a steady-state amplitude response is not generated instantaneously in a flexural ultrasonic transducer from a drive excitation signal, and differences in the drive characteristics between transmitting and receiving transducers can affect the measured response. This research investigates the dynamic performance of flexural ultrasonic transducers using acoustic microphone measurements and laser Doppler vibrometry, supported by a detailed mechanical analog model, in a process which has not before been applied to the flexural ultrasonic transducer. These techniques are employed to gain insights into the physics of their vibration behaviour, vital for the optimisation of industrial ultrasound systems.

The Dynamic Performance of Flexural Ultrasonic Transducers

PubMed Central

Kang, Lei; Rowlands, George; Dixon, Steve

2018-01-01

Flexural ultrasonic transducers are principally used as proximity sensors and for industrial metrology. Their operation relies on a piezoelectric ceramic to generate a flexing of a metallic membrane, which delivers the ultrasound signal. The performance of flexural ultrasonic transducers has been largely limited to excitation through a short voltage burst signal at a designated mechanical resonance frequency. However, a steady-state amplitude response is not generated instantaneously in a flexural ultrasonic transducer from a drive excitation signal, and differences in the drive characteristics between transmitting and receiving transducers can affect the measured response. This research investigates the dynamic performance of flexural ultrasonic transducers using acoustic microphone measurements and laser Doppler vibrometry, supported by a detailed mechanical analog model, in a process which has not before been applied to the flexural ultrasonic transducer. These techniques are employed to gain insights into the physics of their vibration behaviour, vital for the optimisation of industrial ultrasound systems. PMID:29346297

[The effect of core veneer thickness ratio on the flexural strength of diatomite-based dental ceramic].

PubMed

Jiang, Jie; Zhang, Xin; Gao, Mei-qin; Zhang, Fei-min; Lu, Xiao-li

2015-06-01

To evaluate the effect of different core veneer thickness ratios on the flexural strength and failure mode of bilayered diatomite-based dental ceramics. Diatomite-based dental ceramics blocks (16 mm×5.4 mm×1 mm) were sintered with different thickness of veneer porcelains: 0 mm (group A), 0.6 mm (group B), 0.8 mm (group C) and 1.0 mm (group D). Flexural strength was detected and scanning electron microscope was used to observe the interface microstructure. Statistical analysis was performed using SPSS 17.0 software package. With the increase of the thickness of the veneer porcelain, flexural strength of group C showed highest flexural strength up to (277.24±5.47) MPa. Different core veneer thickness ratios can significantly influence the flexural strength of bilayered diatomite-based dental ceramics. Supported by Science and Technology Projects of Nantong City (HS2013010).

Influence of Tension Stiffening on the Flexural Stiffness of Reinforced Concrete Circular Sections

PubMed Central

Morelli, Francesco; Amico, Cosimo; Salvatore, Walter; Squeglia, Nunziante; Stacul, Stefano

2017-01-01

Within this paper, the assessment of tension stiffening effects on a reinforced concrete element with circular section subjected to axial and bending loads is presented. To this purpose, an enhancement of an analytical model already present within the actual technical literature is proposed. The accuracy of the enhanced method is assessed by comparing the experimental results carried out in past research and the numerical ones obtained by the model. Finally, a parametric study is executed in order to study the influence of axial compressive force on the flexural stiffness of reinforced concrete elements that are characterized by a circular section, comparing the secant stiffness evaluated at yielding and at maximum resistance, considering and not considering the effects of tension stiffness. PMID:28773028

Influence of Tension Stiffening on the Flexural Stiffness of Reinforced Concrete Circular Sections.

PubMed

Morelli, Francesco; Amico, Cosimo; Salvatore, Walter; Squeglia, Nunziante; Stacul, Stefano

2017-06-18

Within this paper, the assessment of tension stiffening effects on a reinforced concrete element with the circular sections subjected to axial and bending loads is presented. To this purpose, an enhancement of an analytical model already present within the actual technical literature is proposed. The accuracy of the enhanced method is assessed by comparing the experimental results carried out in past research and the numerical ones obtained by the model. Finally, a parametric study is executed in order to study the influence of axial compressive force on the flexural stiffness of reinforced concrete elements that are characterized by a circular section, comparing the secant stiffness evaluated at yielding and at maximum resistance, considering and not considering the effects of tension stiffness.

Mechanical properties and micro-morphology of fiber posts.

PubMed

Zicari, F; Coutinho, E; Scotti, R; Van Meerbeek, B; Naert, I

2013-04-01

To evaluate flexural properties of different fiber posts systems and to morphologically characterize their micro-structure. Six types of translucent fiber posts were selected: RelyX Post (3M ESPE), ParaPost Taper Lux (Colthéne-Whaledent), GC Fiber Post (GC), LuxaPost (DMG), FRC Postec Plus (Ivoclar-Vivadent), D.T. Light-Post (RTD). For each post system and size, ten specimens were subjected to a three-points bending test. Maximum fracture load, flexural strength and flexural modulus were determined using a universal loading device (5848 MicroTester(®), Instron). Besides, for each system, three intact posts of similar dimensions were processed for scanning electron microscopy to morphologically characterize the micro-structure. The following structural characteristics were analyzed: fibers/matrix ratio, density of fibers, diameter of fibers and distribution of fibers. Data were statistically analyzed with ANOVA. Type and diameter of posts were found to significantly affect the fracture load, flexural strength and flexural modulus (p<0.05). Regarding maximum fracture load, it was found to increase with post diameter, in each post system (p<0.001). Regarding flexural strength and flexural modulus, the highest values were recorded for posts with the smallest diameter (p<0.001). Finally, structural characteristics significantly varied among the post systems tested. However, any correlation has been found between flexural strength and structural characteristics. Flexural strength appeared not to be correlated to structural characteristics of fiber posts, but it may rather be affected by mechanical properties of the resin matrix and the interfacial adhesion between fibers and resin matrix. Copyright © 2013. Published by Elsevier Ltd.

The Effect on the Flexural Strength, Flexural Modulus and Compressive Strength of Fibre Reinforced Acrylic with That of Plain Unfilled Acrylic Resin – An in Vitro Study

PubMed Central

Thomas, Tony C; K, Aswini Kumar; Krishnan, Vinod; Mathew, Anil; V, Manju

2015-01-01

Aim: The aim of this in vitro study was to compare the flexural strength, the flexural modulus and compressive strength of the acrylic polymer reinforced with glass, carbon, polyethylene and Kevlar fibres with that of plain unfilled resin. Materials and Methods: A total of 50 specimens were prepared and divided into 10 specimens each under 5 groups namely group 1- control group without any fibres, group 2 – carbon fibres, group 3- glass fibres, group 4 – polyethylene, group 5- Kevlar. Universal testing machine (Tinius olsen, USA) was used for the testing of these specimens. Out of each group, 5 specimens were randomly selected and testing was done for flexural strength using a three point deflection test and three point bending test for compressive strength and the modulus was plotted using a graphical method. Statistical analysis was done using statistical software. Results: The respective mean values for samples in regard to their flexural strength for PMMA plain, PMMA+ glass fibre, PMMA+ carbon, PMMA+ polyethylene and PMMA+ Kevlar were 90.64, 100.79, 102.58, 94.13 and 96.43 respectively. Scheffes post hoc test clearly indicated that only mean flexural strength values of PMMA + Carbon, has the highest mean value. One-way ANOVA revealed a non-significant difference among the groups in regard to their compressive strength. Conclusion: The study concludes that carbon fibre reinforced samples has the greatest flexural strength and greatest flexural modulus, however the compressive strength remains unchanged. PMID:25954696

Hemostatic variables, plasma lactate concentration, and inflammatory biomarkers in dogs with gastric dilatation-volvulus.

PubMed

Verschoof, J; Moritz, A; Kramer, M; Bauer, N

2015-01-01

Prospective characterization of hemostastatic variables, plasma lactate concentration, and inflammatory biomarkers in dogs with gastric dilatation-volvulus (GDV). Coagulation variables (platelets, prothrombin time [PT], activated partial thromboplastin time [aPTT], fibrinogen, antithrombin [AT], protein C [PC], protein S [PS], D-dimers), plasma lactate concentration and inflammatory biomarkers (C-reactive protein, white blood cell [WBC] count, lymphocyte and neutrophil numbers) were assessed in 20 dogs with GDV presented between 2011 and 2012. Blood was taken preoperatively and at days 1 and 3 postoperatively. The prognostic value of these variables before and after surgery was evaluated as well as the behavior of variables during the study. Overall, 7/20 (35%) dogs did not survive; two dogs (29%) were euthanized during surgery due to severe gastric necrosis and 5 (71%) dogs after surgery due to sepsis and disseminated intravascular coagulopathy. Prior to surgery, median plasma lactate concentration was significantly (p = 0.01) lower in survivors (6.2 mmol/l, range 1.9-9.7 mmol/l) when compared to non-survivors (11.8 mmol/l, range 7.5-16.2 mmol/l). In dogs dying after surgery, significantly higher plasma lactate concentration, coagulation times and D-dimer concentration were present as well as lower fibrinogen concentration and activity of PC and AT compared to survivors. At discharge, activity of AT, PC and PS were markedly below the reference interval in 6/13 (46%), 11/13 (85%), and 8/13 (62%) dogs, respectively. Only lactate plasma concentration was of preoperative prognostic value. After surgery, severe abnormalities of coagulation variables, especially the endogenous anticoagulants were present in most of the dogs. The severity of the abnormalities was associated with survival.

Obligatory symbiotic Wolbachia endobacteria are absent from Loa loa

PubMed Central

Büttner, Dietrich W; Wanji, Samuel; Bazzocchi, Chiara; Bain, Odile; Fischer, Peter

2003-01-01

Background Many filarial nematodes harbour Wolbachia endobacteria. These endobacteria are transmitted vertically from one generation to the next. In several filarial species that have been studied to date they are obligatory symbionts of their hosts. Elimination of the endobacteria by antibiotics interrupts the embryogenesis and hence the production of microfilariae. The medical implication of this being that the use of doxycycline for the treatment of human onchocerciasis and bancroftian filariasis leads to elimination of the Wolbachia and hence sterilisation of the female worms. Wolbachia play a role in the immunopathology of patients and may contribute to side effects seen after antifilarial chemotherapy. In several studies Wolbachia were not observed in Loa loa. Since these results have been doubted, and because of the medical significance, several independent methods were applied to search for Wolbachia in L. loa. Methods Loa loa and Onchocerca volvulus were studied by electron microscopy, histology with silver staining, and immunohistology using antibodies against WSP, Wolbachia aspartate aminotransferase, and heat shock protein 60. The results achieved with L. loa and O. volvulus were compared. Searching for Wolbachia, genes were amplified by PCR coding for the bacterial 16S rDNA, the FTSZ cell division protein, and WSP. Results No Wolbachia endobacteria were discovered by immunohistology in 13 male and 14 female L. loa worms and in numerous L. loa microfilariae. In contrast, endobacteria were found in large numbers in O. volvulus and 14 other filaria species. No intracellular bacteria were seen in electron micrographs of oocytes and young morulae of L. loa in contrast to O. volvulus. In agreement with these results, Wolbachia DNA was not detected by PCR in three male and six female L. loa worms and in two microfilariae samples of L. loa. Conclusions Loa loa do not harbour obligatory symbiotic Wolbachia endobacteria in essential numbers to enable their efficient vertical transmission or to play a role in production of microfilariae. Exclusively, the filariae cause the immunopathology of loiasis is patients and the adverse side effects after antifilarial chemotherapy. Doxycycline cannot be used to cure loiais but it probably does not represent a risk for L. loa patients when administered to patients with co-infections of onchocerciasis. PMID:12801420

A Comparison of the Flexural and Impact Strengths and Flexural Modulus of CAD/CAM and Conventional Heat-Cured Polymethyl Methacrylate (PMMA).

PubMed

Al-Dwairi, Ziad N; Tahboub, Kawkab Y; Baba, Nadim Z; Goodacre, Charles J

2018-06-13

The introduction of computer-aided design/computer-aided manufacturing (CAD/CAM) technology to the field of removable prosthodontics has recently made it possible to fabricate complete dentures of prepolymerized polymethyl methacrylate (PMMA) blocks, which are claimed to be of better mechanical properties; however, no published reports that have evaluated mechanical properties of CAD/CAM PMMA. The purpose of this study was to compare flexural strength, impact strength, and flexural modulus of two brands of CAD/CAM PMMA and a conventional heat-cured PMMA. 45 rectangular specimens (65 mm × 10 mm × 3 mm) were fabricated (15 CAD/CAM AvaDent PMMA specimens from AvaDent, 15 CAD/CAM Tizian PMMA specimens from Shütz Dental, 15 conventional Meliodent PMMA specimens from Heraeus Kulzer) and stored in distilled water at (37  ± 1°C) for 7 days. Specimens (N = 15) in each group were subjected to the three-point bending test and impact strength test, employing the Charpy configuration on unnotched specimens. The morphology of the fractured specimens was studied under a scanning electron microscope (SEM). Statistical analysis was performed using one-way ANOVA and Tukey pairwise multiple comparisons with 95% confidence interval. The Schütz Dental specimens showed the highest mean flexural strength (130.67 MPa) and impact strength (29.56 kg/m 2 ). The highest mean flexural modulus was recorded in the AvaDent group (2519.6 MPa). The conventional heat-cured group showed the lowest mean flexural strength (93.33 MPa), impact strength (14.756 kg/m 2 ), and flexural modulus (2117.2 MPa). Differences in means of flexural properties between AvaDent and Schütz Dental specimens were not statistically significant (p > 0.05). As CAD/CAM PMMA specimens exhibited improved flexural strength, flexural modulus, and impact strength in comparison to the conventional heat-cured groups, CAD/CAM dentures are expected to be more durable. Different brands of CAD/CAM PMMA may have inherent variations in mechanical properties. © 2018 by the American College of Prosthodontists.

Isolated resonator gyroscope with a drive and sense plate

NASA Technical Reports Server (NTRS)

Shcheglov, Kirill V. (Inventor); Challoner, A. Dorian (Inventor)

2006-01-01

The present invention discloses a resonator gyroscope comprising a vibrationally isolated resonator including a proof mass, a counterbalancing plate having an extensive planar region, and one or more flexures interconnecting the proof mass and counterbalancing plate. A baseplate is affixed to the resonator by the one or more flexures and sense and drive electrodes are affixed to the baseplate proximate to the extensive planar region of the counterbalancing plate for exciting the resonator and sensing movement of the gyroscope. The isolated resonator transfers substantially no net momentum to the baseplate when the resonator is excited.

Mechanical performance of porous concrete pavement containing nano black rice husk ash

NASA Astrophysics Data System (ADS)

Ibrahim, M. Y. Mohd; Ramadhansyah, P. J.; Rosli, H. Mohd; Ibrahim, M. H. Wan

2018-01-01

This paper presents an experimental research on the performance of nano black rice husk ash on the porous concrete pavement properties. The performance of the porous concrete pavement mixtures was investigated based on their compressive strength, flexural strength, and splitting tensile strength. The results indicated that using nano material from black rice husk ash improved the mechanical properties of porous concrete pavement. In addition, the result of compressive, flexural, and splitting tensile strength was increased with increasing in curing age. Finally, porous concrete pavement with 10% replacement levels exhibited an excellent performance with good strength compared to others.

Design optimization of continuous partially prestressed concrete beams

NASA Astrophysics Data System (ADS)

Al-Gahtani, A. S.; Al-Saadoun, S. S.; Abul-Feilat, E. A.

1995-04-01

An effective formulation for optimum design of two-span continuous partially prestressed concrete beams is described in this paper. Variable prestressing forces along the tendon profile, which may be jacked from one end or both ends with flexibility in the overlapping range and location, and the induced secondary effects are considered. The imposed constraints are on flexural stresses, ultimate flexural strength, cracking moment, ultimate shear strength, reinforcement limits cross-section dimensions, and cable profile geometries. These constraints are formulated in accordance with ACI (American Concrete Institute) code provisions. The capabilities of the program to solve several engineering problems are presented.

Flexural controls on late Neogene basin evolution in southern McMurdo Sound, Antarctica

NASA Astrophysics Data System (ADS)

Aitken, Alan R. A.; Wilson, Gary S.; Jordan, Thomas; Tinto, Kirsty; Blakemore, Hamish

2012-01-01

The basins of southern McMurdo Sound have evolved under the influence of lithospheric flexure induced by the loads of the Erebus Volcanic Province. To characterise these basins, it is important to investigate the lithosphere's flexural properties, and estimate their influence on basin architecture and evolution. Seismic and gravity data are used to constrain 3D forward modelling of the progressive development of accommodation space within the flexural basins. Elastic plate flexure was calculated for a range of effective elastic thicknesses (T e) from 0.5 to 25 km using a spectral method. Models with low, but nonzero, T e values (2 km < T e < 5 km) produce the best fit to the gravity data, although uncertainty is high due to inaccuracies in the Digital Elevation Model. The slopes of flexural horizons revealed in seismic reflection lines are consistent with this, indicating a T e of 2 km to 5 km, although the depths to these horizons are not consistent, perhaps due to a northwards slope, or step, in the pre-flexural surface. These results indicate that the lithospheric strength of southern McMurdo Sound is significantly less than estimates of the regional average (T e ~ 20 km). This low strength may reflect the weakening effects of the Terror Rift, and perhaps also the Discovery Accommodation Zone, a region of major transverse faulting. A low T e model (T e = 3) for southern McMurdo Sound predicts the development of two discrete flexural depressions, each 2-2.5 km deep. The predicted stratigraphy of the northern basin reflects flexure due to Ross Island, predominantly erupted since ca. 1.8 Ma. The predicted stratigraphy of the southern basin reflects more gradual flexure from ca. 10 Ma to ca. 2 Ma, due to the more dispersed volcanoes of the Discovery subprovince. Collectively, these two basins have the potential to preserve a remarkable stratigraphic record of Antarctic climate change through the late Neogene.

Reprint of: Flexural controls on late Neogene basin evolution in southern McMurdo Sound, Antarctica

NASA Astrophysics Data System (ADS)

Aitken, Alan R. A.; Wilson, Gary S.; Jordan, Tom; Tinto, Kirsty; Blakemore, Hamish

2012-10-01

The basins of southern McMurdo Sound have evolved under the influence of lithospheric flexure induced by the loads of the Erebus Volcanic Province. To characterise these basins, it is important to investigate the lithosphere's flexural properties, and estimate their influence on basin architecture and evolution. Seismic and gravity data are used to constrain 3D forward modelling of the progressive development of accommodation space within the flexural basins. Elastic plate flexure was calculated for a range of effective elastic thicknesses (Te) from 0.5 to 25 km using a spectral method. Models with low, but nonzero, Te values (2 km < Te < 5 km) produce the best fit to the gravity data, although uncertainty is high due to inaccuracies in the Digital Elevation Model. The slopes of flexural horizons revealed in seismic reflection lines are consistent with this, indicating a Te of 2 km to 5 km, although the depths to these horizons are not consistent, perhaps due to a northwards slope, or step, in the pre-flexural surface. These results indicate that the lithospheric strength of southern McMurdo Sound is significantly less than estimates of the regional average (Te ~ 20 km). This low strength may reflect the weakening effects of the Terror Rift, and perhaps also the Discovery Accommodation Zone, a region of major transverse faulting. A low Te model (Te = 3) for southern McMurdo Sound predicts the development of two discrete flexural depressions, each 2-2.5 km deep. The predicted stratigraphy of the northern basin reflects flexure due to Ross Island, predominantly erupted since ca. 1.8 Ma. The predicted stratigraphy of the southern basin reflects more gradual flexure from ca. 10 Ma to ca. 2 Ma, due to the more dispersed volcanoes of the Discovery subprovince. Collectively, these two basins have the potential to preserve a remarkable stratigraphic record of Antarctic climate change through the late Neogene.

Flexural behavior of the fibrous cementitious composites (FCC) containing hybrid fibres

NASA Astrophysics Data System (ADS)

Ramli, Mahyuddin; Ban, Cheah Chee; Samsudin, Muhamad Fadli

2018-02-01

In this study, the flexural behavior of the fibrous cementitious composites containing hybrid fibers was investigated. Waste materials or by product materials such as pulverized fuel ash (PFA) and ground granulated blast-furnace slag (GGBS) was used as supplementary cement replacement. In addition, barchip and kenaf fiber will be used as additional materials for enhance the flexural behavior of cementitious composites. A seven mix design of fibrous cementitious composites containing hybrid fiber mortar were fabricated with PFA-GGBS as cement replacement at 50% with hybridization of barchip and kenaf fiber between 0.5% and 2.0% by total volume weight. The FCC with hybrid fibers mortar will be fabricated by using 50 × 50 × 50 mm, 40 × 40 × 160 mm and 350 × 125 × 30 mm steel mold for assessment of mechanical performances and flexural behavior characteristics. The flexural behavior and mechanical performance of the PFA-GGBS with hybrid fiber mortar block was assessed in terms of load deflection response, stress-strain response, crack development, compressive and flexural strength after water curing for 28 days. Moreover, the specimen HBK 1 and HBK 2 was observed equivalent or better in mechanical performance and flexural behavior as compared to control mortar.

Light-weight sandwich panel honeycomb core with hybrid carbon-glass fiber composite skin for electric vehicle application

NASA Astrophysics Data System (ADS)

Cahyono, Sukmaji Indro; Widodo, Angit; Anwar, Miftahul; Diharjo, Kuncoro; Triyono, Teguh; Hapid, A.; Kaleg, S.

2016-03-01

The carbon fiber reinforced plastic (CFRP) composite is relative high cost material in current manufacturing process of electric vehicle body structure. Sandwich panels consisting polypropylene (PP) honeycomb core with hybrid carbon-glass fiber composite skin were investigated. The aim of present paper was evaluate the flexural properties and bending rigidity of various volume fraction carbon-glass fiber composite skins with the honeycomb core. The flexural properties and cost of panels were compared to the reported values of solid hybrid Carbon/Glass FRP used for the frame body structure of electric vehicle. The finite element model of represented sandwich panel was established to characterize the flexural properties of material using homogenization technique. Finally, simplified model was employed to crashworthiness analysis for engine hood of the body electric vehicle structure. The good cost-electiveness of honeycomb core with hybrid carbon-glass fiber skin has the potential to be used as a light-weight alternative material in body electric vehicle fabricated.

Analysis of flexural wave cloaks

NASA Astrophysics Data System (ADS)

Climente, Alfonso; Torrent, Daniel; Sánchez-Dehesa, José

2016-12-01

This work presents a comprehensive study of the cloak for bending waves theoretically proposed by Farhat et al. [see Phys. Rev. Lett. 103, 024301 (2009)] and later on experimentally realized by Stenger et al. [see Phys. Rev. Lett. 108, 014301 (2012)]. This study uses a semi-analytical approach, the multilayer scattering method, which is based in the Kirchoff-Love wave equation for flexural waves in thin plates. Our approach was unable to reproduce the predicted behavior of the theoretically proposed cloak. This disagreement is here explained in terms of the simplified wave equation employed in the cloak design, which employed unusual boundary conditions for the cloaking shell. However, our approach reproduces fairly well the measured displacement maps for the fabricated cloak, indicating the validity of our approach. Also, the cloak quality has been here analyzed using the so called averaged visibility and the scattering cross section. The results obtained from both analysis let us to conclude that there is room for further improvements of this type of flexural wave cloak by using better design procedures.

Determination of Temperature- Dependent Mechanical Properties of Carbon Composites Under Tensile and Flexural Loading

NASA Astrophysics Data System (ADS)

Chripunow, Andre; Kubisch, Aline; Ruder, Matthias; Forster, Andreas; Korber, Hannes

2014-06-01

The presented test setup utilises a custom-built furnace realising test temperatures of up to 500°C. In order to ensure always optimal test conditions the temperature cell can be exchanged depending on the mechanical tests and specimen sizes. Cells for tensile and flexural loadings had been developed. With the latter one it is possible to perform three-point-bending tests, interlaminar-shear-strength tests as well as tests to determine the interlaminar fracture toughness. In this work the effect of fibre orientation on the mechanical properties of CFRP prepreg material under tensile and flexural loads at elevated temperatures was studied. Especially the matrix dominated layups showed a rather early decay of the mechanical properties even at temperatures quite lower than Tg. An analytical model has been used to describe the temperature-dependent properties. The model shows good agreement concerning the strength whereas the proper prediction of the moduli was only possible for the matrix dominated layups.

Transformation elastodynamics and cloaking for flexural waves

NASA Astrophysics Data System (ADS)

Colquitt, D. J.; Brun, M.; Gei, M.; Movchan, A. B.; Movchan, N. V.; Jones, I. S.

2014-12-01

The paper addresses an important issue of cloaking transformations for fourth-order partial differential equations representing flexural waves in thin elastic plates. It is shown that, in contrast with the Helmholtz equation, the general form of the partial differential equation is not invariant with respect to the cloaking transformation. The significant result of this paper is the analysis of the transformed equation and its interpretation in the framework of the linear theory of pre-stressed plates. The paper provides a formal framework for transformation elastodynamics as applied to elastic plates. Furthermore, an algorithm is proposed for designing a broadband square cloak for flexural waves, which employs a regularised push-out transformation. Illustrative numerical examples show high accuracy and efficiency of the proposed cloaking algorithm. In particular, a physical configuration involving a perturbation of an interference pattern generated by two coherent sources is presented. It is demonstrated that the perturbation produced by a cloaked defect is negligibly small even for such a delicate interference pattern.

Composite resin reinforced with pre-tensioned glass fibers. Influence of prestressing on flexural properties.

PubMed

Schlichting, Luís Henrique; de Andrada, Mauro Amaral Caldeira; Vieira, Luiz Clóvis Cardoso; de Oliveira Barra, Guilherme Mariz; Magne, Pascal

2010-02-01

This investigation evaluated the flexural properties of two composite resins, and the influence of unidirectional glass fiber reinforcements, with and without pre-tensioning. Two composite resins (Q: Quixfil and A: Adoro) were used to fabricate 2 mm x 2 mm x 25 mm beams (N = 10), reinforced with two fiber bundles along the long axis of the beam and pre-tensioned under a load equivalent to 73.5% of its tensile strength (groups QPF and APF). In two other experimental groups, the bundles were similarly positioned but without pre-tension (groups QF and AF). Two more groups were included without fiber reinforcement (control groups Q and A). After 24h storage, specimens were subjected to a three-point flexural bending test to establish the flexural module, the deflection at initial failure and the flexural strength. Data were analyzed using a two-way analysis of variance (composite resin system and fiber reinforcement type) and the Tukey HSD post hoc tests (alpha = .05). The results showed that prestressing increased the flexural module of Adoro specimens (p<.001) but not Quixfil (p = .17). Prestressed beams reached greater deflection at initial failure than those conventionally reinforced (p<.001), namely .85-1.35 mm for Adoro and .66-.90 mm for Quixfil. Prestressing also significantly increased the flexural strength of beams (p<.001) in both Adoro and Quixfil groups, from 443.46 to 569.15 MPa and from 425.47 to 568.00 MPa, respectively. Pre-tensioning of unidirectional glass fibers increased both deflection until initial failure and flexural strength of Quixfil and Adoro composite resins, however, with limited effects on the flexural modulus. Copyright 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Surface orientation effects on bending properties of surgical mesh are independent of tensile properties.

PubMed

Simon, David D; Andrews, Sharon M; Robinson-Zeigler, Rebecca; Valdes, Thelma; Woods, Terry O

2018-02-01

Current mechanical testing of surgical mesh focuses primarily on tensile properties even though implanted devices are not subjected to pure tensile loads. Our objective was to determine the flexural (bending) properties of surgical mesh and determine if they correlate with mesh tensile properties. The flexural rigidity values of 11 different surgical mesh designs were determined along three textile directions (machine, cross-machine, and 45° to machine; n = 5 for each) using ASTM D1388-14 while tracking surface orientation. Tensile testing was also performed on the same specimens using ASTM D882-12. Linear regressions were performed to compare mesh flexural rigidity to mesh thickness, areal mass density, filament diameter, ultimate tensile strength, and maximum extension. Of 33 mesh specimen groups, 30 had significant differences in flexural rigidity values when comparing surface orientations (top and bottom). Flexural rigidity and mesh tensile properties also varied with textile direction (machine and cross-machine). There was no strong correlation between the flexural and tensile properties, with mesh thickness having the best overall correlation with flexural rigidity. Currently, surface orientation is not indicated on marketed surgical mesh, and a single mesh may behave differently depending on the direction of loading. The lack of correlation between flexural stiffness and tensile properties indicates the need to examine mesh bending stiffness to provide a more comprehensive understanding of surgical mesh mechanical behaviors. Further investigation is needed to determine if these flexural properties result in the surgical mesh behaving mechanically different depending on implantation direction. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 854-862, 2018. © 2017 Wiley Periodicals, Inc.

Evaluation of fracture toughness and mechanical properties of ternary thiol-ene-methacrylate systems as resin matrix for dental restorative composites.

PubMed

Beigi, Saeed; Yeganeh, Hamid; Atai, Mohammad

2013-07-01

Study and evaluation of fracture toughness, flexural and dynamic mechanical properties, and crosslink density of ternary thiol-ene-methacrylate systems and comparison with corresponding conventional methacrylate system were considered in the present study. Urethane tetra allyl ether monomer (UTAE) was synthesized as ene monomer. Different formulations were prepared based on combination of UTAE, BisGMA/TEGDMA and a tetrathiol monomer (PETMP). The photocuring reaction was conducted under visible light using BD/CQ combination as photoinitiator system. Mechanical properties were evaluated via measuring flexural strength, flexural modulus and fracture toughness. Scanning electron microscopy (SEM) was utilized to study the morphology of the fractured specimen's cross section. Viscoelastic properties of the samples were also determined by dynamic mechanical thermal analysis (DMTA). The same study was performed on a conventional methacrylate system. The data were analyzed and compared by ANOVA and Tukey HSD tests (significance level=0.05). The results showed improvement in fracture toughness of the specimens containing thiol-ene moieties. DMTA revealed a lower glass transition temperature and more homogenous structure for thiol-ene containing specimens in comparison to the system containing merely methacrylate monomer. The flexural modulus and flexural strength of the specimens with higher thiol-ene content were lower than the neat methacrylate system. The SEM micrographs of the fractured surface of specimens with higher methacrylate content were smooth and mirror-like (shiny) which represent brittle fracture. The thiol-ene-methacrylate system can be used as resin matrix of dental composites with enhanced fracture toughness in comparison to the methacrylate analogous. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Evaluation of machinability and flexural strength of a novel dental machinable glass-ceramic.

PubMed

Qin, Feng; Zheng, Shucan; Luo, Zufeng; Li, Yong; Guo, Ling; Zhao, Yunfeng; Fu, Qiang

2009-10-01

To evaluate the machinability and flexural strength of a novel dental machinable glass-ceramic (named PMC), and to compare the machinability property with that of Vita Mark II and human enamel. The raw batch materials were selected and mixed. Four groups of novel glass-ceramics were formed at different nucleation temperatures, and were assigned to Group 1, Group 2, Group 3 and Group 4. The machinability of the four groups of novel glass-ceramics, Vita Mark II ceramic and freshly extracted human premolars were compared by means of drilling depth measurement. A three-point bending test was used to measure the flexural strength of the novel glass-ceramics. The crystalline phases of the group with the best machinability were identified by X-ray diffraction. In terms of the drilling depth, Group 2 of the novel glass-ceramics proves to have the largest drilling depth. There was no statistical difference among Group 1, Group 4 and the natural teeth. The drilling depth of Vita MK II was statistically less than that of Group 1, Group 4 and the natural teeth. Group 3 had the least drilling depth. In respect of the flexural strength, Group 2 exhibited the maximum flexural strength; Group 1 was statistically weaker than Group 2; there was no statistical difference between Group 3 and Group 4, and they were the weakest materials. XRD of Group 2 ceramic showed that a new type of dental machinable glass-ceramic containing calcium-mica had been developed by the present study and was named PMC. PMC is promising for application as a dental machinable ceramic due to its good machinability and relatively high strength.

Combined laparoscopic ovariectomy and laparoscopic-assisted gastropexy in dogs susceptible to gastric dilatation-volvulus

PubMed Central

Rivier, Pablo; Furneaux, Rob; Viguier, Eric

2011-01-01

This prospective study describes a simple method of combining laparoscopic ovariectomy and laparoscopic-assisted prophylactic gastropexy and determines the duration of surgery, complications, and long-term outcome including prevention of gastric dilatation-volvulus (GDV). Laparoscopic ovariectomy and laparoscopic-assisted gastropexy were performed on 26 sexually intact female dogs susceptible to GDV. The mean surgery time was 60.8 ± 12.4 min. No GDV episode was seen during the study period (mean follow-up: 5.2 ± 1.4 y). All dogs had an intact gastropexy attachment assessed by ultrasonography at 1 y. Post-operative complications were minor and owners were satisfied with the procedure. Combined laparoscopic ovariectomy and laparoscopic- assisted gastropexy appears to be a successful and low morbidity alternative procedure to both ovariectomy/ovariohysterectomy and gastropexy via open ventral-midline laparotomy. PMID:21461209

Combined laparoscopic ovariectomy and laparoscopic-assisted gastropexy in dogs susceptible to gastric dilatation-volvulus.

PubMed

Rivier, Pablo; Furneaux, Rob; Viguier, Eric

2011-01-01

This prospective study describes a simple method of combining laparoscopic ovariectomy and laparoscopic-assisted prophylactic gastropexy and determines the duration of surgery, complications, and long-term outcome including prevention of gastric dilatation-volvulus (GDV). Laparoscopic ovariectomy and laparoscopic-assisted gastropexy were performed on 26 sexually intact female dogs susceptible to GDV. The mean surgery time was 60.8 ± 12.4 min. No GDV episode was seen during the study period (mean follow-up: 5.2 ± 1.4 y). All dogs had an intact gastropexy attachment assessed by ultrasonography at 1 y. Post-operative complications were minor and owners were satisfied with the procedure. Combined laparoscopic ovariectomy and laparoscopic- assisted gastropexy appears to be a successful and low morbidity alternative procedure to both ovariectomy/ovariohysterectomy and gastropexy via open ventral-midline laparotomy.

Small intestinal obstruction by remnants of the omphalomesenteric duct: findings on contrast enema.

PubMed

Fenton, L Z; Buonomo, C; Share, J C; Chung, T

2000-03-01

We reviewed the contrast enema examinations and medical records of six patients with small intestinal obstruction due to omphalomesenteric duct remnant to evaluate for characteristic imaging findings. In five out of the six patients the point of obstruction was demonstrated on the enema; in three patients, the characteristic "beak" of a volvulus was seen, either in the terminal ileum or cecum. In three patients, there was medial deviation of the cecum. The characteristic radiographic features of volvulus at the cecum or terminal ileum and medial deviation of the cecum should suggest persistence of an omphalomesenteric duct remnant as the etiology of obstruction in a child less than 2 years of age. The appearance of omphalomesenteric duct remnant obstruction on enema examination, though not specific, is characteristic and should be familiar to pediatric radiologists.

Postoperative management of dogs with gastric dilatation and volvulus.

PubMed

Bruchim, Yaron; Kelmer, Efrat

2014-09-01

The objective of the study was to review the veterinary literature for evidence-based and common clinical practice supporting the postoperative management of dogs with gastric dilatation and volvulus (GDV). GDV involves rapid accumulation of gas in the stomach, gastric volvulus, increased intragastric pressure, and decreased venous return. GDV is characterized by relative hypovolemic-distributive and cardiogenic shock, during which the whole body may be subjected to inadequate tissue perfusion and ischemia. Intensive postoperative management of the patients with GDV is essential for survival. Therapy in the postoperative period is focused on maintaining tissue perfusion along with intensive monitoring for prevention and early identification of ischemia-reperfusion injury (IRI) and consequent potential complications such as hypotension, cardiac arrhythmias, acute kidney injury (AKI), gastric ulceration, electrolyte imbalances, and pain. In addition, early identification of patients in need for re-exploration owing to gastric necrosis, abdominal sepsis, or splenic thrombosis is crucial. Therapy with intravenous lidocaine may play a central role in combating IRI and cardiac arrhythmias. The most serious complications of GDV are associated with IRI and consequent systemic inflammatory response syndrome and multiple organ dysfunction syndrome. Other reported complications include hypotension, AKI, disseminated intravascular coagulation, gastric ulceration, and cardiac arrhythmias. Despite appropriate medical and surgical treatment, the reported mortality rate in dogs with GDV is high (10%-28%). Dogs with GDV that are affected with gastric necrosis or develop AKI have higher mortality rates. Copyright © 2014 Elsevier Inc. All rights reserved.

Gross and histologic evaluation of hepatogastric ligaments in clinically normal dogs and dogs with gastric dilatation-volvulus.

PubMed

Hall, J A; Willer, R L; Seim, H B; Powers, B E

1995-12-01

OBJECTIVE--To investigate any potential structural differences in hepatogastric ligaments between clinically normal dogs and dogs with gastric dilatation-volvulus (GDV). DESIGN--Case-control study. ANIMALS--Hepatogastric ligaments were examined in 13 large-breed control dogs and in 13 large-breed dogs referred for surgical treatment of GDV. PROCEDURE--Measurements and biopsies of hepatogastric ligaments were performed at the time of surgery, circumcostal gastropexy, for correction of GDV. Serial sections from each ligament were stained with H&E, Masson's trichrome, and elastin stains to assess morphology, including smooth muscle, collagen, and elastic fiber contents. RESULTS--There were no differences observed by light microscopy in incidence or degree of histopathologic alterations between the 2 groups of dogs. The lengths of hepatogastric ligaments in GDV-affected dogs, however, were significantly longer than those of control dogs (GDV-affected dogs, 7.0 [5.0 to 9.5] cm median [range]; control dogs, 5.0 [3.0 to 7.5] cm median [range]; P = 0.01). CONCLUSIONS--Causality can not be inferred from this study. It is not known whether the ligaments were lengthened as a result of GDV or whether the lengthened ligaments predisposed dogs to GDV. CLINICAL RELEVANCE--This finding may reflect increased laxity of the supporting hepatogastric ligament in the right quadrant of the abdomen. An elongated ligament may permit increased stomach mobility and predispose dogs to partial or complete gastric volvulus.

Use of ultrasonography to diagnose large colon volvulus in horses.

PubMed

Abutarbush, Sameeh M

2006-02-01

To describe the use of ultrasonography to diagnose large colon volvulus (LCV) in horses. Descriptive report. 4 horses with clinical signs of abdominal pain. Each horse was administered analgesic agents for pain control and placed in stocks. Ultrasonographic evaluations were performed with a 3.5-MHz sector scanning transducer that was placed parallel to the long axis of the horse (longitudinal imaging) over an area of the left ventral aspect of the abdomen. The boundaries of the evaluated region included the ventral midline, 2 vertical lines at the level of the left 10th and 17th intercostal spaces, and a horizontal line between the 2 vertical lines at the level of the costal arch of the left 10th intercostal area. In all horses, nonsacculated large colon was identified ultrasonographically in the left ventral portion of the abdomen; this finding was considered indicative of LCV. In 3 horses, the LCV involved intestinal rotation of 180 degrees, whereas in 1 horse, the LCV involved intestinal rotation of 540 degrees. As confirmed by surgical or postmortem findings, the degree and location of the volvulus were correctly estimated from ultrasonographic images. In horses, this method of diagnosis of LCV appears to be of value regardless of the location at which the rotation of the large colon occurs. Ultrasonographic findings may aid in the earlier diagnosis of LCV in horses, especially at an early stage of the disease when other clinical signs are equivocal.

Methods for strengthening reinforced concrete bridge girders containing poorly detailed flexural steel using near-surface mounted metallics.

DOT National Transportation Integrated Search

2015-08-01

Many older reinforced concrete deck girder (RCDG) bridges contain straight-bar terminations of flexural reinforcement in : flexural tension zones without special detailing. Common bridge design practice of the 1950s did not consider the additional : ...

Effects of metal- and fiber-reinforced composite root canal posts on flexural properties.

PubMed

Kim, Su-Hyeon; Oh, Tack-Oon; Kim, Ju-Young; Park, Chun-Woong; Baek, Seung-Ho; Park, Eun-Seok

2016-01-01

The aim of this study was to observe the effects of different test conditions on the flexural properties of root canal post. Metal- and fiber-reinforced composite root canal posts of various diameters were measured to determine flexural properties using a threepoint bending test at different conditions. In this study, the span length/post diameter ratio of root canal posts varied from 3.0 to 10.0. Multiple regression models for maximum load as a dependent variable were statistically significant. The models for flexural properties as dependent variables were statistically significant, but linear regression models could not be fitted to data sets. At a low span length/post diameter ratio, the flexural properties were distorted by occurrence of shear stress in short samples. It was impossible to obtain high span length/post diameter ratio with root canal posts. The addition of parameters or coefficients is necessary to appropriately represent the flexural properties of root canal posts.

Geometric controls of the flexural gravity waves on the Ross Ice Shelf

NASA Astrophysics Data System (ADS)

Sergienko, O. V.

2017-12-01

Long-period ocean waves, formed locally or at distant sources, can reach sub-ice-shelf cavities and excite coupled motion in the cavity and the ice shelf - flexural gravity waves. Three-dimensional numerical simulations of the flexural gravity waves on the Ross Ice Shelf show that propagation of these waves is strongly controlled by the geometry of the system - the cavity shape, its water-column thickness and the ice-shelf thickness. The results of numerical simulations demonstrate that propagation of the waves is spatially organized in beams, whose orientation is determined by the direction of the of the open ocean waves incident on the ice-shelf front. As a result, depending on the beams orientation, parts of the Ross Ice Shelf experience significantly larger flexural stresses compared to other parts where the flexural gravity beams do not propagate. Very long-period waves can propagate farther away from the ice-shelf front exciting flexural stresses in the vicinity of the grounding line.

Behaviour of partially composite precast concrete sandwich panels under flexural and axial loads

NASA Astrophysics Data System (ADS)

Tomlinson, Douglas George

Precast concrete sandwich panels are commonly used on building exteriors. They are typically composed of two concrete wythes that surround rigid insulation. They are advantageous as they provide both structural and thermal resistance. The structural response of sandwich panels is heavily influenced by shear connectors that link the wythes together. This thesis presents a study on partially composite non-prestressed precast concrete wall panels. Nine flexure tests were conducted on a wall design incorporating 'floating' concrete studs and Glass Fibre Reinforced Polymer (GFRP) connectors. The studs encapsulate and stiffen the connectors, reducing shear deformations. Ultimate loads increased from 58 to 80% that of a composite section as the connectors' reinforcement ratio increased from 2.6 to 9.8%. This design was optimized by reinforcing the studs and integrating them with the structural wythe; new connectors composed of angled steel or Basalt-FRP (BFRP) were used. The load-slip response of the new connector design was studied through 38 double shear push-through tests using various connector diameters and insertion angles. Larger connectors were stronger but more likely to pull out. Seven flexure tests were conducted on the new wall design reinforced with different combinations of steel and BFRP connectors and reinforcement. Composite action varied from 50 to 90% depending on connector and reinforcement material. Following this study, the axial-bending interaction curves were established for the new wall design using both BFRP and steel connectors and reinforcement. Eight panels were axially loaded to predesignated loads then loaded in flexure to failure. A technique is presented to experimentally determine the effective centroid of partially composite sections. Beyond the tension and compression-controlled failure regions of the interaction curve, a third region was observed in between, governed by connector failure. Theoretical models were developed for the bond-slip behaviour of the shear connection and to analyze the full panel's flexural and axial response to determine the longitudinal shear force transferred between wythes and account for partial composite behavior. The models were validated against experiments and used to conduct a parametric study. Among several interesting findings, the study demonstrated how composite action increases with the slenderness of axially loaded panels.

Extensional Fault Evolution and its Flexural Isostatic Response During Iberia-Newfoundland Rifted Margin Formation

NASA Astrophysics Data System (ADS)

Gómez-Romeu, J.; Kusznir, N.; Manatschal, G.; Roberts, A.

2017-12-01

During the formation of magma-poor rifted margins, upper lithosphere thinning and stretching is achieved by extensional faulting, however, there is still debate and uncertainty how faults evolve during rifting leading to breakup. Seismic data provides an image of the present-day structural and stratigraphic configuration and thus initial fault geometry is unknown. To understand the geometric evolution of extensional faults at rifted margins it is extremely important to also consider the flexural response of the lithosphere produced by fault displacement resulting in footwall uplift and hangingwall subsidence. We investigate how the flexural isostatic response to extensional faulting controls the structural development of rifted margins. To achieve our aim, we use a kinematic forward model (RIFTER) which incorporates the flexural isostatic response to extensional faulting, crustal thinning, lithosphere thermal loads, sedimentation and erosion. Inputs for RIFTER are derived from seismic reflection interpretation and outputs of RIFTER are the prediction of the structural and stratigraphic consequences of recursive sequential faulting and sedimentation. Using RIFTER we model the simultaneous tectonic development of the Iberia-Newfoundland conjugate rifted margins along the ISE01-SCREECH1 and TGS/LG12-SCREECH2 seismic lines. We quantitatively test and calibrate the model against observed target data restored to breakup time. Two quantitative methods are used to obtain this target data: (i) gravity anomaly inversion which predicts Moho depth and continental lithosphere thinning and (ii) reverse post-rift subsidence modelling to give water and Moho depths at breakup time. We show that extensional faulting occurs on steep ( 60°) normal faults in both proximal and distal parts of rifted margins. Extensional faults together with their flexural isostatic response produce not only sub-horizontal exhumed footwall surfaces (i.e. the rolling hinge model) and highly rotated (60° or more) pre- and syn-rift stratigraphy, but also extensional allochthons underlain by apparent horizontal detachments. These detachment faults were never active in this sub-horizontal geometry; they were only active as steep faults which were isostatically rotated to their present sub-horizontal position.

Evolving lithospheric flexure and paleotopography of the Pyrenean Orogen from 3D flexural modeling and basin analysis

NASA Astrophysics Data System (ADS)

Curry, M. E.; van der Beek, P.; Huismans, R. S.; Muñoz, J. A.

2017-12-01

The Pyrenees are an asymmetric, doubly-vergent orogen with retro- and pro- foreland basins that preserve a record of deformation since the Mesozoic. The extensive research and exploration efforts on the mountain belt and flanking foreland basins provide an exceptional dataset for investigating geodynamics and surface processes over large spatial and temporal scales in western Europe. We present the results of a numerical modeling study investigating the spatio-temporal variation in lithospheric flexure in response to the developing orogen. We employ a finite element method to model the 3D flexural deformation of the lithosphere beneath the Pyrenean orogen since the onset of convergence in the late Cretaceous. Using subsurface, geophysical, and structural data, we describe the evolving geometry of both the French Aquitaine and Spanish Ebro foreland basins at the present (post-orogenic), the mid-Eocene (peak orogenic), the Paleocene (early orogenic), and the end of the Cretaceous (pre- to early orogenic). The flexural modeling provides insight into how both the rigidity of the lithosphere and the paleotopographic load have varied over the course of orogenesis to shape the basin geometry. We find that the overriding European plate has higher rigidity than the subducting Iberian plate, with modern Effective Elastic Thickness (EET) values of 20 ± 2 and 12 ± 2 km, respectively. Modeling indicates that the modern rigidity of both plates decreases westward towards the Bay of Biscay. The lithospheric rigidity has increased by 50% since the Mesozoic with early Cenozoic EET values of 13 ± 2 and 8 ± 1 km for the European and Iberian plates, respectively. The topographic load began increasing with convergence in the late Cretaceous, reaching modern levels in the central and eastern Pyrenees by the Eocene. In contrast, the topographic load in the western Pyrenees was 70% of the modern value in the Eocene, and experienced topographic growth through the Oligo-Miocene. The westward propagation of topographic growth and erosion is supported by subsidence analysis and low-temperature thermochronology data. These results have implications for surface processes and foreland basin development of the Pyrenean Orogen, inheritance of Hercynian crustal properties, and the geodynamic evolution of western Europe.

Mechanical properties and material characterization of polysialate structural composites

NASA Astrophysics Data System (ADS)

Foden, Andrew James

One of the major concerns in using Fiber Reinforced Composites in applications that are subjected to fire is their resistance to high temperature. Some of the fabrics used in FRC, such as carbon, are fire resistant. However, almost all the resins used cannot withstand temperatures higher than 200°C. This dissertation deals with the development and use of a potassium aluminosilicate (GEOPOLYMER) resin that is inorganic and can sustain more than 1000°C. The results presented include the mechanical properties of the unreinforced polysialate matrix in tension, flexure, and compression as well as the strain capacities and surface energy. The mechanical properties of the matrix reinforced with several different fabrics were obtained in flexure, tension, compression and shear. The strength and stiffness of the composite was evaluated for each loading condition. Tests were conducted on unexposed samples as well as samples exposed to temperatures from 200 to 1000°C. Fatigue properties were determined using flexural loading. A study of the effect of several processing variables on the properties of the composite was undertaken to determine the optimum procedure for manufacturing composite plates. The processing variables studied were the curing temperature and pressure, and the post cure drying time required to remove any residual water. The optimum manufacturing conditions were determined using the void content, density, fiber volume fraction, and flexural strength. Analytical models are presented based on both micro and macro mechanical analysis of the composite. Classic laminate theory is used to evaluate the state of the composite as it is being loaded to determine the failure mechanisms. Several failure criteria theories are considered. The analysis is then used to explain the mechanical behavior of the composite that was observed during the experimental study.

Erosional dynamics, flexural isostasy, and long-lived escarpments: A numerical modeling study

NASA Technical Reports Server (NTRS)

Tucker, Gregory E.; Slingerland, Rudy L.

1994-01-01

Erosional escarpments common features of high-elevation rifted continets. Fission track data suffest that these escarpments form by base level lowering and/or marginal uplift during rifting, followed by lateral retreat of an erosion front across tens to hundreds of kioometers. Previous modeling studies have shown that this characteristic pattern of denudation can have a profound impact upon marginal isostatic uplift and the evolution of offshore sedimentary basins. Yet at present there is only a rudimentary understanding of the geomorphic mechanisms capable of driving such prolonged escarpment retreat. In this study we present a nonlinear, two-dimensional landscape evolution model tha tis used to asses the necessary and sufficient conditions for long-term retreat of a rift-generated escarpment. The model represents topography as a grid of cells, with drainage networkds evolving as water flows across the grid in the direction of steepest descent. The model accounts for sediment production by weathering, fluvial sediment transport, bedrock channel erosion, and hillslope sediment transport by diffusive mechanisms and by mass failure. Numerical experiments presented explore the effects of different combinations of erosion processes and of dynamic coupling between denudation and flexural isostatic uplift. Model results suggest that the necessary and sufficient conditions for long-term escarpment retreat are (1) incising bedrock channels in which the erosion rate increases with increasing drainage area, so that the channels steepen and propagate headward; (2) a low rate of sediment production relative to sediment transport efficiency, which promotes relief-generating processes over diffusive ones; (3) high continental elevation, which allows greater freedom for fluvial dissection; and (4) any process, including flexural isostatic uplift, that helps to maintain a drainage divide near an escarpment crest. Flexural isostatic uplift also facilitates escarpment, thereby increasing channel gradients and accelerating erosion which in turn generates additional isostatic uplift. Of all the above conditions, high continental elevation is common ot most rift margin escarpments and may ultimately be the most important factor.

Vaccines to combat river blindness: expression, selection and formulation of vaccines against infection with Onchocerca volvulus in a mouse model.

PubMed

Hess, Jessica A; Zhan, Bin; Bonne-Année, Sandra; Deckman, Jessica M; Bottazzi, Maria Elena; Hotez, Peter J; Klei, Thomas R; Lustigman, Sara; Abraham, David

2014-08-01

Human onchocerciasis is a neglected tropical disease caused by Onchocerca volvulus and an important cause of blindness and chronic disability in the developing world. Although mass drug administration of ivermectin has had a profound effect on control of the disease, additional tools are critically needed including the need for a vaccine against onchocerciasis. The objectives of the present study were to: (i) select antigens with known vaccine pedigrees as components of a vaccine; (ii) produce the selected vaccine antigens under controlled conditions, using two expression systems and in one laboratory and (iii) evaluate their vaccine efficacy using a single immunisation protocol in mice. In addition, we tested the hypothesis that joining protective antigens as a fusion protein or in combination, into a multivalent vaccine, would improve the ability of the vaccine to induce protective immunity. Out of eight vaccine candidates tested in this study, Ov-103, Ov-RAL-2 and Ov-CPI-2M were shown to reproducibly induce protective immunity when administered individually, as fusion proteins or in combination. Although there was no increase in the level of protective immunity induced by combining the antigens into one vaccine, these antigens remain strong candidates for inclusion in a vaccine to control onchocerciasis in humans. Copyright © 2014 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Fractography and the Surface Crack in Flexure (SCF) method for evaluating fracture toughness of ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quinn, G.D.; Gettings, R.J.; Kuebler, J.J.

1996-12-31

The surface crack in flexure (SCF) method, also known as the controlled surface flaw method, has been used to measure fracture toughness of ceramics and glasses for almost 20 years. New fracture toughness results for a range of ceramics and glasses including alumina, boron carbide, silicon carbide, silicon nitride, titanium diboride, zirconia, glass ceramic, borosilicate crown glass, and a whisker-reinforced alumina are presented in this paper. Some materials are conducive to precrack measurements, while others are not. New techniques for detecting the precracks are presented. A surprising outcome from a recently concluded Versailles Advanced Materials and Standards (VAMAS) round robinmore » project was that the computed toughness is often not sensitive to the exact precrack size measurement. Consistent results were obtained by many laboratories despite different viewing modes and magnifications. The reasons for this consistency and why toughness is insensitive to precrack size is presented.« less

Effects of Simulated Functional Loading Conditions on Dentin, Composite, and Laminate Structures

PubMed Central

Walker, Mary P.; Teitelbaum, Heather K.; Eick, J. David; Williams, Karen B.

2008-01-01

Use of composite restorations continues to increase, tempered by more potential problems when placed in posterior dentition. Thus, it is essential to understand how these materials function under stress-bearing clinical conditions. Since mastication is difficult to replicate in the laboratory, cyclic loading is frequently used within in vitro evaluations but often employs traditional fatigue testing, which typically does not simulate occlusal loading because higher stresses and loading frequencies are used, so failure mechanisms may be different. The present investigation utilized relevant parameters (specimen size; loading frequency) to assess the effects of cyclic loading on flexural mechanical properties and fracture morphology of (coronal) dentin, composite, and dentin-adhesive-composite “laminate” structures. Incremental monitoring of flexural modulus on individual beams over 60,000 loading cycles revealed a gradual increase across materials; post-hoc comparisons indicated statistical significance only for 1 versus 60k cycles. Paired specimens were tested (one exposed to 60k loading cycles, one to static loading only), and comparisons of flexural modulus and strength showed statistically significantly higher values for cyclically-loaded specimens across materials, with no observable differences in fracture morphology. Localized reorganization of dentin collagen and polymer chains could have increased flexural modulus and strength during cyclic loading, which may have implications toward the life and failure mechanisms of clinical restorations and underlying tooth structure. PMID:18823019

Splenic abscess owing to cancer at the splenic flexure

PubMed Central

Awotar, Gavish K.; Luo, Fuwen; Zhao, Zhengdong; Guan, Guoxin; Ning, Shili; Ren, Jinshuai; Liu, Yaqing; Wang, Guangzhi; Liu, Pixu

2016-01-01

Abstract Background: The cancer of the splenic flexure of the colon is a rare medical entity with severe morbidity because of its insidious onset. Methods: We present the case of a 59-year-old male patient with dull left upper quadrant pain, leukocytosis, and anemia. A splenic abscess described as an air-fluid level with splenocolic fistula was found on CT scan imaging. Surgery was done for splenic pus drainage. He was again admitted 2 months later for intestinal obstruction. Results: An exploratory laparotomy showed multiple hard, gray liver nodules as well as a hard mass in the small bowel. Owing to extensive adhesions and a late stage of cancer involvement, the splenic flexure tumor was not resected. A loop transverse colostomy was done and a ColoplastTM Colostomy bag placed. We also reviewed the literature-linking colon cancer and splenic abscess with specific attention to the carcinoma of the splenic flexure. As the latter invades through the spleen matter, there is the creation of a splenocolic fistula, which allows the migration of normal gut flora into the spleen. This leads to the formation of the splenic abscess. Conclusion: This is the 13th case report pertaining to invading colonic cancer causing a splenic abscess. Although the treatment for splenic abscesses is shifting from splenectomy to image-guided percutaneous pus drainage, the few reported cases make the proper management of such complication still unclear. PMID:27661050

Spatiotemporal distribution of extracellular matrix changes during mouse duodenojejunal flexure formation.

PubMed

Onouchi, Sawa; Ichii, Osamu; Nakamura, Teppei; Elewa, Yaser Hosny Ali; Kon, Yasuhiro

2016-08-01

Although gut flexures characterize gut morphology, the mechanisms underlying flexure formation remain obscure. Previously, we analyzed the mouse duodenojejunal flexure (DJF) as a model for its formation and reported asymmetric morphologies between the inner and outer bending sides of the fetal mouse DJF, implying their contribution to DJF formation. We now present the extracellular matrix (ECM) as an important factor for gut morphogenesis. We investigate ECM distribution during mouse DJF formation by histological techniques. In the intercellular space of the gut wall, high Alcian-Blue positivity for proteoglycans shifted from the outer to the inner side of the gut wall during DJF formation. Immunopositivity for fibronectin, collagen I, or pan-tenascin was higher at the inner than at the outer side. Collagen IV and laminins localized to the epithelial basement membrane. Beneath the mesothelium at the pre-formation stage, collagen IV and laminin immunopositivity showed inverse results, corresponding to the different cellular characteristics at this site. At the post-formation stage, however, laminin positivity beneath the mesothelium was the reverse of that observed during the pre-formation stage. High immunopositivity for collagen IV and laminins at the inner gut wall mesenchyme of the post-formation DJF implied a different blood vessel distribution. We conclude that ECM distribution changes spatiotemporally during mouse DJF formation, indicating ECM association with the establishment of asymmetric morphologies during this process.

Method and apparatus for actively controlling a micro-scale flexural plate wave device

DOEpatents

Dohner, Jeffrey L.

2001-01-01

An actively controlled flexural plate wave device provides a micro-scale pump. A method of actively controlling a flexural plate wave device produces traveling waves in the device by coordinating the interaction of a magnetic field with actively controlled currents. An actively-controlled flexural plate wave device can be placed in a fluid channel and adapted for use as a micro-scale fluid pump to cool or drive micro-scale systems, for example, micro-chips, micro-electrical-mechanical devices, micro-fluid circuits, or micro-scale chemical analysis devices.

Flexure bearing support, with particular application to stirling machines

DOEpatents

Beckett, Carl D.; Lauhala, Victor C.; Neely, Ron; Penswick, Laurence B.; Ritter, Darren C.; Nelson, Richard L.; Wimer, Burnell P.

1996-01-01

The use of flexures in the form of flat spiral springs cut from sheet metal materials provides support for coaxial nonrotating linear reciprocating members in power conversion machinery, such as Stirling cycle engines or heat pumps. They permit operation with little or no rubbing contact or other wear mechanisms. The relatively movable members include one member having a hollow interior structure within which the flexures are located. The flexures permit limited axial movement between the interconnected members, but prevent adverse rotational movement and radial displacement from their desired coaxial positions.

Flexure bearing support, with particular application to Stirling machines

DOEpatents

Beckett, C.D.; Lauhala, V.C.; Neely, R.; Penswick, L.B.; Ritter, D.C.; Nelson, R.L.; Wimer, B.P.

1996-06-04

The use of flexures in the form of flat spiral springs cut from sheet metal materials provides support for coaxial non-rotating linear reciprocating members in power conversion machinery, such as Stirling cycle engines or heat pumps. They permit operation with little or no rubbing contact or other wear mechanisms. The relatively movable members include one member having a hollow interior structure within which the flexures are located. The flexures permit limited axial movement between the interconnected members, but prevent adverse rotational movement and radial displacement from their desired coaxial positions. 8 figs.

Influence of manufacturing parameters on the strength of PLA parts using Layered Manufacturing technique: A statistical approach

NASA Astrophysics Data System (ADS)

Jaya Christiyan, K. G.; Chandrasekhar, U.; Mathivanan, N. Rajesh; Venkateswarlu, K.

2018-02-01

A 3D printing was successfully used to fabricate samples of Polylactic Acid (PLA). Processing parameters such as Lay-up speed, Lay-up thickness, and printing nozzle were varied. All samples were tested for flexural strength using three point load test. A statistical mathematical model was developed to correlate the processing parameters with flexural strength. The result clearly demonstrated that the lay-up thickness and nozzle diameter influenced flexural strength significantly, whereas lay-up speed hardly influenced the flexural strength.

Plate equations for piezoelectrically actuated flexural mode ultrasound transducers.

PubMed

Perçin, Gökhan

2003-01-01

This paper considers variational methods to derive two-dimensional plate equations for piezoelectrically actuated flexural mode ultrasound transducers. In the absence of analytical expressions for the equivalent circuit parameters of a flexural mode transducer, it is difficult to calculate its optimal parameters and dimensions, and to choose suitable materials. The influence of coupling between flexural and extensional deformation, and coupling between the structure and the acoustic volume on the dynamic response of piezoelectrically actuated flexural mode transducer is analyzed using variational methods. Variational methods are applied to derive two-dimensional plate equations for the transducer, and to calculate the coupled electromechanical field variables. In these methods, the variations across the thickness direction vanish by using the stress resultants. Thus, two-dimensional plate equations for a stepwise laminated circular plate are obtained.

Variations in lithospheric thickness on Venus

NASA Technical Reports Server (NTRS)

Johnson, C. L.; Sandwell, David T.

1992-01-01

Recent analyses of Magellan data have indicated many regions exhibiting topograhic flexure. On Venus, flexure is associated predominantly with coronae and the chasmata with Aphrodite Terra. Modeling of these flexural signatures allows the elastic and mechanical thickness of the lithosphere to be estimated. In areas where the lithosphere is flexed beyond its elastic limit the saturation moment provides information on the strength of the lithosphere. Modeling of 12 flexural features on Venus has indicated lithospheric thicknesses comparable with terrestrial values. This has important implications for the venusian heat budget. Flexure of a thin elastic plate due simultaneously to a line load on a continuous plate and a bending moment applied to the end of a broken plate is considered. The mean radius and regional topographic gradient are also included in the model. Features with a large radius of curvature were selected so that a two-dimensional approximation could be used. Comparisons with an axisymmetric model were made for some features to check the validity of the two-dimensional assumption. The best-fit elastic thickness was found for each profile crossing a given flexural feature. In addition, the surface stress and bending moment at the first zero crossing of each profile were also calculated. Flexural amplitudes and elastic thicknesses obtained for 12 features vary significantly. Three examples of the model fitting procedures are discussed.

Effect of silver nano particles on flexural strength of acrylic resins.

PubMed

Sodagar, Ahmad; Kassaee, Mohammad Zaman; Akhavan, Azam; Javadi, Negar; Arab, Sepideh; Kharazifard, Mohammad Javad

2012-04-01

Poly(methyl methacrylate), PMMA, is widely used for fabrication of removable orthodontic appliances. Silver nano particles (AgNps) have been added to PMMA because of their antimicrobial properties. The aim of this study is to investigate the effect of AgNps on the flexural strength of PMMA. Acrylic liquid containing 0.05% and 0.2% AgNps was prepared for two kinds of acrylic resins: Rapid Repair &Selecta Plus. Two groups without AgNps were used as control groups. For each one, flexural strength was investigated via Three Point Bending method for the 15 acrylic blocks. Two-way ANOVA, one way ANOVA and Tukey tests were used for statistical analysis. Rapid Repair without AgNps showed the highest flexural strength. Addition of 0.05% AgNps to Rapid Repair, significantly decreased its flexural strength while, continuing the addition up to 0.2% increased it nearly up to its primary level. In contrast, addition of AgNps to Selecta Plus increased its flexural strength but addition of 0.05% nano particles was more effective than 0.2%. The effect of AgNps on flexural strength of PMMA depends on several factors including the type of acrylics and the concentrations of nano particles. Copyright © 2011 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Paleobathymetry from 3-D flexural backstripping: Implementation and application to NW Australia and Liberia passive margins

NASA Astrophysics Data System (ADS)

Lovely, Peter; Chauvin, Benjamin; Brennan, Patrick; Laroche, Matt

2015-04-01

Understanding paleobathymetry is important to hydrocarbon explorationists, as it impacts depositional environments, reservoir quality, source rock preservation, hydrocarbon migration pathways, and paleo-stress. At long wavelengths (basin scale), bathymetry is controlled predominantly by isostatic compensation of vertical loads, which include sediment, water and spatial and temporal variations in the thickness and temperature of the crust and lithospheric mantle. Roberts, et al. (2003) present a workflow to account for these loads and derive paleobathymetry by 3-D flexural backstripping. However, to our knowledge, commercially packaged software for flexural backstripping is limited to two dimensions, and 3-D software is limited to Airy isostasy, which does not account for the elastic stiffness of the earth's crust and may, as a result, produce local error of 1km or more. We have developed a 3-D backstripping application that incorporates flexural isostasy, and is implemented in a workflow modeled after Roberts, et al. (2003). The application restores the isostatic components of basin geometry and bathymetry, and may account for the effects of sediment loading (isostasy & compaction), and rift-related subsidence (post- and syn-rift effects of homogeneous or depth-dependent pure-shear stretching models. Effects of dynamic topography, if quantifiable, may be prescribed as a bulk shift after backstripping. Implemented as a plug-in to Gocad, the application is accessible to a broad audience of geoscientists. The flexural isostasy implementation accounts for basin geometry and spatially heterogeneous layer thickness by discretizing each layer as a series of cylindrical loads of varying density and thickness at the nodes of a square grid. The isostatic effect of a single cylindrical load is provided by Brotchie & Silvester (1969) and the effect of multiple loads may be summed linearly. An iterative approach for calculating local water depth accounts for variations in eustatic sea level, allows for emergent topography, and overcomes potential pitfalls associated with the analytical solution for a "filled" basin. We review the numerical implementation of flexural backstripping, and discuss implications, as well as limitations, of paleobathymetric maps for source rock preservation and reservoir presence in two diverse passive margin settings: offshore Liberia and the Northwest Shelf of Australia.

Flexural bending of southern Tibet in a retro foreland setting

PubMed Central

Wang, Erchie; Kamp, Peter J. J.; Xu, Ganqing; Hodges, Kip V.; Meng, Kai; Chen, Lin; Wang, Gang; Luo, Hui

2015-01-01

The highest elevation of the Tibetan Plateau, lying 5,700 m above sea level, occurs within the part of the Lhasa block immediately north of the India-Tibet suture zone (Yarlung Zangbo suture zone, YZSZ), being 700 m higher than the maximum elevation of more northern parts of the plateau. Various mechanisms have been proposed to explain this differentially higher topography and the rock uplift that led to it, invoking crustal compression or extension. Here we present the results of structural investigations along the length of the high elevation belt and suture zone, which rather indicate flexural bending of the southern margin of the Lhasa block (Gangdese magmatic belt) and occurrence of an adjacent foreland basin (Kailas Basin), both elements resulting from supra-crustal loading of the Lhasa block by the Zangbo Complex (Indian plate rocks) via the Great Counter Thrust. Hence we interpret the differential elevation of the southern margin of the plateau as due originally to uplift of a forebulge in a retro foreland setting modified by subsequent processes. Identification of this flexural deformation has implications for early evolution of the India-Tibet continental collision zone, implying an initial (Late Oligocene) symmetrical architecture that subsequently transitioned into the present asymmetrical wedge architecture. PMID:26174578

Wave propagation and power flow in an acoustic metamaterial plate with lateral local resonance attachment

NASA Astrophysics Data System (ADS)

Wang, Ting; Sheng, Meiping; Ding, Xiaodong; Yan, Xiaowei

2018-03-01

This paper presents analysis on wave propagation and power flow in an acoustic metamaterial plate with lateral local resonance. The metamaterial is designed to have lateral local resonance systems attached to a homogeneous plate. Relevant theoretical analysis, numerical modelling and application prospect are presented. Results show that the metamaterial has two complete band gaps for flexural wave absorption and vibration attenuation. Damping can smooth and lower the metamaterial’s frequency responses in high frequency ranges at the expense of the band gap effect, and as an important factor to calculate the power flow is thoroughly investigated. Moreover, the effective mass density becomes negative and unbounded at specific frequencies. Simultaneously, power flow within band gaps are dramatically blocked from the power flow contour and power flow maps. Results from finite element modelling and power flow analysis reveal the working mechanism of the flexural wave attenuation and power flow blocked within the band gaps, where part of the flexural vibration is absorbed by the vertical resonator and the rest is transformed through four-link-mechanisms to the lateral resonators that oscillate and generate inertial forces indirectly to counterbalance the shear forces induced by the vibrational plate. The power flow is stored in the vertical and lateral local resonance, as well as in the connected plate.

Isolated resonator gyroscope with isolation trimming using a secondary element

NASA Technical Reports Server (NTRS)

Challoner, A. Dorian (Inventor); Shcheglov, Kirill V. (Inventor)

2006-01-01

The present invention discloses a resonator gyroscope including an isolated resonator. One or more flexures support the isolated resonator and a baseplate is affixed to the resonator by the flexures. Drive and sense elements are affixed to the baseplate and used to excite the resonator and sense movement of the gyroscope. In addition, at least one secondary element (e.g., another electrode) is affixed to the baseplate and used for trimming isolation of the resonator. The resonator operates such that it transfers substantially no net momentum to the baseplate when the resonator is excited. Typically, the isolated resonator comprises a proof mass and a counterbalancing plate.

Design of a Minimum Surface-Effect Three Degree-of-Freedom Micromanipulator

NASA Technical Reports Server (NTRS)

Goldfarb, Michael; Speich, John E.

1997-01-01

This paper describes the fundamental physical motivations for small-scale minimum surface-effect design, and presents a three degree-of-freedom micromanipulator design that incorporates a minimum surface-effect approach. The primary focus of the design is the split-tube flexure, a unique small-scale revolute joint that exhibits a considerably larger range of motion and significantly better multi-axis revolute joint characteristics than a conventional flexure. The development of this joint enables the implementation of a small-scale spatially-loaded revolute joint-based manipulator with well-behaved kinematic characteristics and without the backlash and stick-slip behavior that would otherwise prevent precision control

Steel Fibers Reinforced Concrete Pipes - Experimental Tests and Numerical Simulation

NASA Astrophysics Data System (ADS)

Doru, Zdrenghea

2017-10-01

The paper presents in the first part a state of the art review of reinforced concrete pipes used in micro tunnelling realised through pipes jacking method and design methods for steel fibres reinforced concrete. In part two experimental tests are presented on inner pipes with diameters of 1410mm and 2200mm, and specimens (100x100x500mm) of reinforced concrete with metal fibres (35 kg / m3). In part two experimental tests are presented on pipes with inner diameters of 1410mm and 2200mm, and specimens (100x100x500mm) of reinforced concrete with steel fibres (35 kg / m3). The results obtained are analysed and are calculated residual flexural tensile strengths which characterise the post-cracking behaviour of steel fibres reinforced concrete. In the third part are presented numerical simulations of the tests of pipes and specimens. The model adopted for the pipes test was a three-dimensional model and loads considered were those obtained in experimental tests at reaching breaking forces. Tensile stresses determined were compared with mean flexural tensile strength. To validate tensile parameters of steel fibres reinforced concrete, experimental tests of the specimens were modelled with MIDAS program to reproduce the flexural breaking behaviour. To simulate post - cracking behaviour was used the method σ — ε based on the relationship stress - strain, according to RILEM TC 162-TDF. For the specimens tested were plotted F — δ diagrams, which have been superimposed for comparison with the similar diagrams of experimental tests. The comparison of experimental results with those obtained from numerical simulation leads to the following conclusions: - the maximum forces obtained by numerical calculation have higher values than the experimental values for the same tensile stresses; - forces corresponding of residual strengths have very similar values between the experimental and numerical calculations; - generally the numerical model estimates a breaking force greater than that obtained in the experimental tests. Experimental and numerical studies are used to establish the residual characteristic flexural tensile strength minimum guaranteed and limits of applicability of concrete pipes reinforced with steel fibres used in various field and loading situations.

Effect of heat polymerization conditions and microwave on the flexural strength of polymethyl methacrylate

PubMed Central

Ozkir, Serhat Emre; Yilmaz, Burak; Unal, Server Mutluay; Culhaoglu, Ahmet; Kurkcuoglu, Isin

2018-01-01

Objective: The objective of this study is the effect of different heat polymerization conditions on the strength of polymethyl methacrylate (PMMA) resin base is unknown. Distinguishing one method that provides improved mechanical properties may be beneficial to the clinical success of complete and partial dentures and overdentures. The purpose of this study was to evaluate the effect of different polymerization methods on the flexural strength of a dental PMMA resin. Materials and Methods: Forty PMMA specimens (64 mm × 10 mm × 4 mm) were prepared with 4 different polymerization methods (n = 10); heat polymerization at 74°C for 9 h, at 100°C for 40 min, and with 620 kPa pressure at 100°C for 20 min. The remaining group of specimens was microwave polymerized at 180 W for 6 min. All specimens were thermocycled at 5°C and 55°C for 5000 times. Three-point flexure test was used to measure the flexural strength of specimens. One-way ANOVA and Tukey Honestly Significant Difference were applied to analyze the differences in flexural strengths (α = 0.05). Results: The flexural strength of heat-polymerized groups was similar. The flexural strength of microwave polymerized group was significantly different and lower than the other groups (P < 0.05). Conclusion: Polymerizing conventional heat-polymerizing PMMA resin with microwave energy resulted in a significant decrease in flexural strength. The results of this study suggest that clinicians may benefit from using heat polymerization when processing PMMA denture bases instead of microvawe polymerization when tested brand is used. PMID:29657535

Evaluation of cyclic flexural fatigue of M-wire nickel-titanium rotary instruments.

PubMed

Al-Hadlaq, Solaiman M S; Aljarbou, Fahad A; AlThumairy, Riyadh I

2010-02-01

This study was conducted to investigate cyclic flexural fatigue resistance of GT series X rotary files made from the newly developed M-wire nickel-titanium alloy compared with GT and Profile nickel-titanium files made from a conventional nickel-titanium alloy. Fifteen files, size 30/0.04, of each type were used to evaluate the cyclic flexural fatigue resistance. A simple device was specifically constructed to measure the time each file type required to fail under cyclic flexural fatigue testing. The results of this experiment indicated that the GT series X files had superior cyclic flexural fatigue resistance than the other 2 file types made from a conventional nickel-titanium alloy (P = .004). On the other hand, the difference between the Profile and the GT files was not statistically significant. The findings of this study suggest that size 30/0.04 nickel-titanium rotary files made from the newly developed M-wire alloy have better cyclic flexural fatigue resistance than files of similar design and size made from the conventional nickel-titanium alloy. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Stomach gas analyses in canine acute gastric dilatation with volvulus.

PubMed

Van Kruiningen, H J; Gargamelli, C; Havier, J; Frueh, S; Jin, L; Suib, S

2013-01-01

The origin of the gas in the stomachs of dogs with acute gastric dilatation or gastric dilatation with volvulus (GDV) often is disputed. We tested the hypothesis that gaseous distention resulted from aerophagia. Ten cases of GDV that were submitted to an emergency clinic were sampled intraoperatively. With the abdomen open, the needle of a vacutainer blood collection set was inserted into the distended stomach, and gas was collected into 10 mL glass vacutainer vials with rubber stoppers. These were stored at room temperature for 1-7 days and then analyzed by gas chromatography and mass spectroscopy. CO2 composition ranged from 13 to 20%. One dog had an H2 concentration of 29%. Because the CO2 content of atmospheric air is less than 1%, these findings suggest that the gaseous gastric distention in GDV is not the result of aerophagia. Copyright © 2013 by the American College of Veterinary Internal Medicine.

GASTRIC DILATATION VOLVULUS IN ADULT MANED WOLVES (CHRYSOCYON BRACHYURUS).

PubMed

Hinton, Jenna D; Padilla, Luis R; Joyner, Priscilla H; Schnellbacher, Rodney; Walsh, Timothy F; Aitken-Palmer, Copper

2017-06-01

Gastric dilatation volvulus (GDV) was identified in six adult maned wolves ( Chrysocyon brachyurus ) housed at the Smithsonian Conservation Biology Institute in Front Royal, Virginia, and the Dickerson Park Zoo in Springfield, Missouri. Four individuals were found dead in their enclosures, and GDV was diagnosed postmortem based on radiographic and necropsy findings. Two individuals were diagnosed with GDV antemortem, with one wolf surviving following surgical intervention and supportive management. A concurrent splenic torsion was identified in three of six cases. Although GDV has been well documented in domestic dogs and is known to occur in maned wolves, objective, detailed case descriptions have been limited in this species. This report represents the first description of a surviving case of GDV in the maned wolf. Thorough species-specific documentation of any acutely fatal condition, such as GDV, is imperative for proper case recognition and medical management, with profound implications for species recovery efforts.

Diet-related risk factors for gastric dilatation-volvulus in dogs of high-risk breeds.

PubMed

Raghavan, Malathi; Glickman, Nita; McCabe, George; Lantz, Gary; Glickman, Lawrence T

2004-01-01

A nested case-control study was conducted among 1634 dogs with complete diet information in a 5-year prospective study to determine diet-related risk factors for gastric dilatation-volvulus (GDV). Cases included 106 dogs that developed GDV; controls included 212 dogs without GDV that were frequency matched to cases by year of GDV onset. Proportionate energy consumed from major food types and from carbohydrates was determined. Dogs were categorized as consuming either a low volume or high volume of food based on the median number of cups of food fed per kg of body weight per meal. Dogs fed a larger volume of food per meal were at a significantly (P<0.05) increased risk of GDV, regardless of the number of meals fed daily. For both large- and giant-breed dogs, the risk of GDV was highest for dogs fed a larger volume of food once daily.

Occurrence and recurrence of gastric dilatation with or without volvulus after incisional gastropexy.

PubMed

Przywara, John F; Abel, Steven B; Peacock, John T; Shott, Susan

2014-10-01

This study investigated recurrence of gastric dilatation without (GD) or with volvulus (GDV) after incisional gastropexy (IG) in dogs that underwent IG for prevention of GDV. Signalment, concurrent surgical procedures, presence of GD or GDV at the time of IG were obtained from medical records of dogs that underwent IG. Owners were contacted to determine whether the dogs experienced GD or GDV after IG, dates of postoperative GD or GDV episodes, survival status, date of death for deceased dogs. Gastric dilatation and GDV recurrence rates were calculated for 40 dogs that had at least 2 y follow-up from the time when IG was performed and for dogs that experienced GD or GDV during the follow-up period. No dogs experienced GDV after IG and 2 dogs (5.0%) experienced GD after IG. The results suggest that GD and GDV rates after IG may be comparable to recurrence rates after other methods of gastropexy.

A case of child death caused by intestinal volvulus following magnetic toy ingestion.

PubMed

Olczak, Mieszko; Skrzypek, Ewa

2015-05-01

An 8-year boy was admitted to the ER of one of Warsaw's pediatric hospitals with a history of having bloody vomiting the day before. During admission the boy collapsed and lost consciousness. CPR was unsuccessful. On medico-legal autopsy, two foreign objects (small magnetic spheres--0.5 cm in diameter) were found in two different places in the small and large intestines and were notably attracted magnetically one to another. A loop of approximately 1-m length with features of small intestinal hemorrhagic necrosis and small intestinal mechanical obstruction was found. The cause of death was intestinal volvulus and small intestinal mechanical obstruction caused by ingestion of foreign objects (two neodymium magnets). Most likely these small magnetic spheres were part of a popular toy, the safety of which, lately, has been widely discussed. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Flexural resistance of heat-pressed and CAD-CAM lithium disilicate with different translucencies.

PubMed

Fabian Fonzar, Riccardo; Carrabba, Michele; Sedda, Maurizio; Ferrari, Marco; Goracci, Cecilia; Vichi, Alessandro

2017-01-01

To compare flexural strength of CAD-CAM and heat-pressed lithium disilicate. For Pressed specimens (Group A), acrylate polymer blocks were cut with a saw in bars shape. Sprueing, investing and preheating procedures were carried out following manufacturer's instructions. IPS e.max Press ingots (Ivoclar-Vivadent) were divided into subgroups (n=15) according to translucency: A.1=HT-A3; A.2=MT-A3; A.3=LT-A3; A.4=MO2. Ingots were then pressed following manufacturer's instructions. For CAD-CAM specimens (Group B) blocks of IPS e.max CAD (Ivoclar-Vivadent) were divided into subgroups: B.1=HT-A3; B.2=MT-A3; B.3=LT-A3; B.4=MO2. Specimens (n=15) were obtained by cutting the blocks with a saw. Final crystallization was performed following manufacturer's instructions. Both Press and CAD specimens were polished and finished with silica carbide papers of increasing grit. Final dimensions of the specimens were 4.0±0.2mm, 1.2±0.2mm, and 16.0±0.2mm. Specimens were tested using a three-point bending test. Flexural strength, Weibull modulus, and Weibull characteristic strength were calculated. Flexural strength data were statistically analyzed. The overall means of Press and CAD specimens did not differ significantly. Within the Press group different translucencies were found to have similar flexural strength. Within the CAD group, statistically significant differences emerged among the tested translucencies (p<0.001). Specifically, MT had significantly higher flexural strength than HT and MO. Also, LT exhibited significantly higher flexural strength than MO. The choice between IPS e.max Press and IPS e.max CAD formulations can be based on different criteria than flexural resistance. Within each formulation, for IPS e.max Press translucency does not affect the flexural strength while for IPS e.max CAD it is an influential factor. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Effect of thickness and surface modifications on flexural strength of monolithic zirconia.

PubMed

Ozer, Fusun; Naden, Andrew; Turp, Volkan; Mante, Francis; Sen, Deniz; Blatz, Markus B

2017-10-14

A recommended minimum thickness for monolithic zirconia restorations has not been reported. Assessing a proper thickness that has the necessary load-bearing capacity but also conserves dental hard tissues is essential. The purpose of this in vitro study was to evaluate the effect of thickness and surface modifications on monolithic zirconia after simulated masticatory stresses. Monolithic zirconia disks (10 mm in diameter) were fabricated with 1.3 mm and 0.8 mm thicknesses. For each thickness, 21 disks were fabricated. The specimens of each group were further divided into 3 subgroups (n=7) according to the surface treatments applied: untreated (control), airborne-particle abrasion with 50-μm Al 2 O 3 particles at a pressure of 400 kPa at 10 mm, and grinding with a diamond rotary instrument followed by polishing. The biaxial flexure strength was determined by using a piston-on-3-balls technique in a universal testing machine. Flexural loading was applied with a 1.4-mm diameter steel cylinder, centered on the disk, at a crosshead speed of 0.5 mm/min until fracture occurred. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were performed. The data were statistically analyzed with 2-way ANOVA, Tamhane T2, 1-way ANOVA, and Student t tests (α=.05). The 1.3-mm specimens had significantly higher flexural strength than the 0.8-mm specimens (P<.05). Airborne-particle abrasion significantly increased the flexural strength (P<.05). Grinding and polishing did not affect the flexural strength of the specimens (P>.05). The mean flexural strength of 0.8-mm and 1.3-mm thick monolithic zirconia was greater than reported masticatory forces. Airborne-particle abrasion increased the flexural strength of monolithic zirconia. Grinding did not affect flexural strength if subsequently polished. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Evaluation of initial plasma lactate values as a predictor of gastric necrosis and initial and subsequent plasma lactate values as a predictor of survival in dogs with gastric dilatation-volvulus: 84 dogs (2003-2007).

PubMed

Green, Tiffany I; Tonozzi, Caroline C; Kirby, Rebecca; Rudloff, Elke

2011-02-01

To test whether an initial plasma lactate ≥ 6.0 mmol/L is associated with the presence of macroscopic gastric wall necrosis and overall survival in dogs presenting with gastric dilatation-volvulus (GDV). Additionally, if no association was identified we sought to identify a different predictive initial plasma lactate concentration and to examine whether serial plasma lactate concentrations provide better prediction of survival. Retrospective study over a 5-year period (2003-2007). Urban private referral small animal teaching hospital. Eighty-four client-owned dogs with a diagnosis of GDV and plasma lactate measurements. None. There was no statistically significant relationship found between survival and the presence of macroscopic gastric wall necrosis with the initial plasma lactate ≥ 6 mmol/L. There was a significant relationship between the initial plasma lactate >2.9 mmol/L for predicting necrosis and <4.1 mmol/L for predicting survival to discharge. Forty dogs that had an increased initial plasma lactate (>2.5 mmol/L) also had a subsequent plasma lactate measured within 12 hours of presentation, with 37/40 dogs surviving and 70% of these surviving dogs having the subsequent lactate decrease by ≥ 50% within 12 hours. The 3/40 that died failed to decrease their plasma lactate by ≥ 50% from the initial blood lactate. The results of this study indicate that an initial presenting plasma lactate concentration ≥ 6.0 mmol/L is not predictive of macroscopic gastric wall necrosis or survival in dogs presenting with GDV. A decrease in plasma lactate concentrations ≥ 50% within 12 hours may be a good indicator for survival. Limitations to the study include its retrospective nature, the small number of patients, and the number of dogs that were euthanized rather than allowed to progress to a natural outcome. © Veterinary Emergency and Critical Care Society 2011.