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1

Fluid-structure interaction in abdominal aortic aneurysms: effects of asymmetry and wall thickness  

Microsoft Academic Search

BACKGROUND: Abdominal aortic aneurysm (AAA) is a prevalent disease which is of significant concern because of the morbidity associated with the continuing expansion of the abdominal aorta and its ultimate rupture. The transient interaction between blood flow and the wall contributes to wall stress which, if it exceeds the failure strength of the dilated arterial wall, will lead to aneurysm

Christine M Scotti; Alexander D Shkolnik; Satish C Muluk; Ender A Finol

2005-01-01

2

Abdominal wall surgery  

MedlinePLUS

Abdominal wall surgery is surgery that improves the appearance of flabby, stretched-out abdominal (belly) muscles and skin. ... mini-tummy tuck" to more complicated, extensive surgery. Abdominal wall surgery is not the same as liposuction, which ...

3

[Full-thickness abdominal wall closure of laparoscopic trocar incision sites: a new, simplified technique].  

PubMed

Description of a safe, quick, easy and cheap technique of suture closure of laparoscopic trocar sites utilizing a reusable instrument ("hook-needle") developed for the purpose. The procedure is done under laparoscopic vision without the need for laparoscopic suture handling and results in a one stage closure of all relevant layers of the abdominal wall. Other techniques recently published for the same purpose are critically reviewed. PMID:8925703

Schwegler, I; Riedtmann-Klee, H J; Aeberhard, P

1996-07-01

4

The Effects of Modified Wall Squat Exercises on Average Adults' Deep Abdominal Muscle Thickness and Lumbar Stability  

PubMed Central

[Purpose] The purpose of this study was to compare the effects of bridge exercises applying the abdominal drawing-in method and modified wall squat exercises on deep abdominal muscle thickness and lumbar stability. [Subjects] A total of 30 subjects were equally divided into an experimental group and a control group. [Methods] The experimental group completed modified wall squat exercises, and the control group performed bridge exercises. Both did so for 30 minutes three times per week over a six-week period. Both groups’ transversus abdominis (Tra), internal oblique (IO), and multifidus muscle thickness were measured using ultrasonography, while their static lumbar stability and dynamic lumbar stability were measured using a pressure biofeedback unit. [Results] A comparison of the pre-intervention and post-intervention measures of the experimental group and the control group was made; the Tra and IO thicknesses were significantly different in both groups. [Conclusion] The modified wall squat exercise and bridge exercise affected the thicknesses of the Tra and the IO muscles. While the bridge exercise requirs space and a mattress to lie on, the modified wall squat exercise can be conveniently performed anytime.

Cho, Misuk

2013-01-01

5

Fetal abdominal wall defects.  

PubMed

The most common fetal abdominal wall defects are gastroschisis and omphalocele, both with a prevalence of about three in 10,000 births. Prenatal ultrasound has a high sensitivity for these abnormalities already at the time of the first-trimester nuchal scan. Major unrelated defects are associated with gastroschisis in about 10% of cases, whereas omphalocele is associated with chromosomal or genetic abnormalities in a much higher proportion of cases. Challenges in management of gastroschisis are related to the prevention of late intrauterine death, and the prediction and treatment of complex forms. With omphalocele, the main difficulty is the exclusion of associated conditions, not all diagnosed prenatally. An outline of the postnatal treatment of abdominal wall defects is given. Other rarer forms of abdominal wall defects are pentalogy of Cantrell, omphalocele, bladder exstrophy, imperforate anus, spina bifida complex, prune-belly syndrome, body stalk anomaly, and bladder and cloacal exstrophy; they deserve multidisciplinary counselling and management. PMID:24342556

Prefumo, Federico; Izzi, Claudia

2014-04-01

6

Traumatic abdominal wall hernia  

PubMed Central

INTRODUCTION Traumatic abdominal wall hernia (TAWH) is a rare entity. Most cases occur in children, following an injury from the bicycle handle bar. In adults, it usually results from road traffic accidents (RTA). We present one of the largest reported cases of TAWH following RTA managed by delayed mesh repair. PRESENTATION OF CASE A 35 yr old obese male with RTA was diagnosed with TAWH with 19 cm × 15 cm defect in left flank. As there were no intra abdominal injuries and overlying skin was abraded, he was planned for elective repair after 6 months. On exploration a defect of 30 cm × 45 cm was found extending from midline anteriorly to 8 cm short of midline posteriorly in transverse axis and costal margin to iliac crest in craniocaudal axis. After restoration of bowel into abdominal cavity, primary closure or even approximation of muscular defect was not possible thus a mesh closure using 60 cm × 60 cm prolene mesh in subcutaneous plane was done. After 4 months follow up, patient is healthy and has no recurrence. DISCUSSION Emergent surgical management of TAWH is usually favoured due to high incidence of associated intra abdominal injuries. Delayed repair may be undertaken in selected cases. CONCLUSION TAWH, although rare, should be suspected in cases of RTA with abdominal wall swellings. With time, the hernia defect may enlarge and muscles may undergo atrophy making delayed repair difficult.

Yadav, Siddharth; Jain, Sunil K.; Arora, Jainendra K.; Sharma, Piyush; Sharma, Abhinav; Bhagwan, Jai; Goyal, Kaushal; Sahoo, Bhabani S.

2012-01-01

7

Laparoscopic Morgagni hernia repair using single-site umbilical and full-thickness abdominal wall repair: technical report of two cases.  

PubMed

Single incision laparoscopic surgery is used in many centres for routine cases such as appendectomy, splenectomy and cholecystectomy. Morgagni hernias are uncommon and account for 1-2% of all congenital diaphragmatic hernia. We report our first laparoscopic repair of two Morgagni hernias, using a single umbilical incision and full-thickness abdominal wall repair with standard straight laparoscopic instruments. Operative time was short and compared favourably with the laparoscopic repair. PMID:23519862

van Niekerk, Martin L

2013-01-01

8

Comparison of the Changes in Thickness of the Abdominal Wall Muscles of Stroke Patients According to the Duration of Their Illness as Observed Using Ultrasonographic Images  

PubMed Central

[Purpose] This study was conducted in order to investigate the importance of trunk muscle strength in stroke patients. By comparing the thicknesses of the abdominal wall muscles through ultrasonography, relative to the duration of illness, the results of the objective data were applied. [Methods] Thirty stroke patients were divided into three groups including an acute phase group participating in the study within 1 month after the onset of a stroke (n=10), a subacute phase group participating less than 6 months (n=10) after a stroke, and a chronic phase group participating more than 6 months (n=10) after suffering a stroke. The thicknesses of the transversus abdominis muscles (TrA), internal oblique muscle (IO), and the external oblique muscle (EO) were measured at rest and during abdominal draw-in maneuver (ADIM) in a supine hook-lying position, and their differences were compared. [Results] The results showed that, in comparison of the thicknesses of the paretic and nonparetic sides, the TrA of the subacute phase and chronic phase groups showed significant differences. In addition, the IO of the subacute phase group and the EO of the chronic phase groups also showed significant differences. [Conclusion] According to the duration of illness in stroke patients, the abdominal wall muscles become noticeably infirm and asymmetric. By improving their symmetry, the functions of the trunk muscles can be recovered.

Seo, DongKwon; Lee, SeungWon; Kwon, OhSung

2013-01-01

9

Considerations in Abdominal Wall Reconstruction  

PubMed Central

Reconstruction of complex defects of the central abdomen is both challenging and technically demanding for plastic surgeons. Advancements in the use of pedicle and free tissue transfer along with the use of bioprosthetic and synthetic meshes have provided for novel approaches to these complex defects. Accordingly, detailed knowledge of abdominal wall and lower extremity anatomy in combination with insight into the design, implementation, and limitations of various flaps is essential to solve these complex clinical problems. Although these defects can be attributed to a myriad of etiologic factors, the objectives in abdominal wall reconstruction are consistent and include the restoration of abdominal wall integrity, protection of intraabdominal viscera, and the prevention of herniation. In this article, it is our goal to review pertinent anatomy, pre- and postoperative care regimens, and the various local, regional, and distant flaps that can be utilized in the reconstruction of these complex clinical cases of the central abdomen.

Sacks, Justin M.; Broyles, Justin M.; Baumann, Donald P.

2012-01-01

10

Abdominal Wall Tumors and Their Reconstruction  

Microsoft Academic Search

\\u000a The abdominal wall protects and contains the abdominal viscera, and serves to position and stabilize the thorax and upper\\u000a body in space during movement. Components of the abdominal wall may be completely replaced if needed. The internal protective\\u000a function of the abdominal wall can be replaced with synthetic meshes, fascial flaps, or grafts. External skin can usually\\u000a be replaced with

Gregory A. Dumanian

11

Autologous closure of giant abdominal wall defects.  

PubMed

Split-thickness skin graft coverage of exposed and granulating intestines within large abdominal wall defects provides a life-saving permanent biologic dressing. The resultant abdominal wall defect often is closed with mesh, which may infect and fistulize. This report describes bilateral advancement flaps of the external oblique and recti muscles in 11 patients treated over 3 years. The defects, which averaged 16 x 24 cm, were due to necrotizing fasciitis subsequent to trauma with bowel perforation (3 patients), multiple ventral herniorrhaphies (2 patients), perforated diverticulitis (4 patients), and perforated peptic ulcer (2 patients). Eight patients were initially treated elsewhere where closure was achieved by split-thickness skin graft in five patients or mesh in 3 patients; 3 developed enterocutaneous fistulae and were transferred for closure while receiving long-term antibiotic and total parenteral nutrition therapy. All 11 patients had successful primary closure. The 8 patients operated on electively had primary healing; 2 developed seromas. Two of the three patients operated on urgently developed superficial wound infections; both healed by second intent without compromise of the primary closure. The following conclusions can be drawn: (1) the linea alba survives despite necrotizing fasciitis, (2) a tension-free primary closure is feasible; (3) morbidity is minimal, and (4) the long-term result is excellent. PMID:9655268

Lucas, C E; Ledgerwood, A M

1998-07-01

12

Spontaneous Endometriosis of the Abdominal Wall  

Microsoft Academic Search

Background: The abdominal wall is the commonest site of extrapelvic endometriosis, which usually develops in association with a prior surgical scar. Case: A 28-year-old woman with two endometriomas in the recti abdominis, which developed in a scarless abdomen. Conclusions: Abdominal wall endometrioma can develop spontaneously in the absence of prior surgical scar and should be considered in the differential diagnosis

Steve C. Ideyi; Moshe Schein; Massoma Niazi; Paul H. Gerst

2003-01-01

13

Genetics Home Reference: Abdominal wall defect  

MedlinePLUS

... is inherited in the pattern of that condition. Where can I find information about diagnosis or management ... genetics professional in my area? in the Handbook. Where can I find additional information about abdominal wall ...

14

Desmoid tumours of the anterior abdominal wall  

Microsoft Academic Search

Aims:To review the surgical management and outcomes for large desmoid tumours of the abdominal wall.Methods:Seven patients with large desmoid tumours of the anterior abdominal wall were treated by wide local excision and reconstruction with two layers of Marlex V mesh (Bard, Galway, Ireland).Results:No patient having initial surgery at this hospital has either a significant residual functional deficit or developed a

R. J. Sutton; J. M. Thomas

1999-01-01

15

Flap Coverage of Anterior Abdominal Wall Defects  

PubMed Central

Reconstruction of complex defects of the anterior abdomen is both challenging and technically demanding for reconstructive surgeons. Advancements in the use of pedicle and free tissue transfer along with the use of bioprosthetic and synthetic meshes have provided for novel approaches to these complex defects. Accordingly, detailed knowledge of abdominal wall and lower extremity anatomy in combination with insight into the design, implementation, and limitations of various flaps is essential to solve these complex clinical problems. Although these defects can be attributed to a myriad of etiologic factors, the objectives in abdominal wall reconstruction are consistent and include the restoration of abdominal wall integrity, protection of intraabdominal viscera, and the prevention of herniation. In this article, the authors review pertinent anatomy and the various local, regional, and distant flaps that can be utilized in the reconstruction of these complex clinical cases of the anterior abdomen.

Sacks, Justin M.; Broyles, Justin M.; Baumann, Donald P.

2012-01-01

16

Bioprosthetic Mesh in Abdominal Wall Reconstruction  

PubMed Central

Mesh materials have undergone a considerable evolution over the last several decades. There has been enhancement of biomechanical properties, improvement in manufacturing processes, and development of antiadhesive laminate synthetic meshes. The evolution of bioprosthetic mesh materials has markedly changed our indications and methods for complex abdominal wall reconstruction. The authors review the optimal properties of bioprosthetic mesh materials, their evolution over time, and their indications for use. The techniques to optimize outcomes are described using bioprosthetic mesh for complex abdominal wall reconstruction. Bioprosthetic mesh materials clearly have certain advantages over other implantable mesh materials in select indications. Appropriate patient selection and surgical technique are critical to the successful use of bioprosthetic materials for abdominal wall repair.

Baumann, Donald P.; Butler, Charles E.

2012-01-01

17

Tube wall thickness measurement apparatus  

DOEpatents

An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

Lagasse, P.R.

1985-06-21

18

Tube wall thickness measurement apparatus  

DOEpatents

An apparatus for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

Lagasse, Paul R. (Santa Fe, NM)

1987-01-01

19

Intraperitoneal haemorrhage from anterior abdominal wall varices.  

PubMed Central

Patients with oesophageal varices frequently present with gastrointestinal haemorrhage but bleeding from varices at other sites is rare. We present a patient with hepatitis C-induced cirrhosis and partial portal vein occlusion who developed spontaneous haemorrhage from anterior abdominal wall varices into the rectus abdominus muscle and peritoneal cavity. Images Figure 1

Hunt, J. B.; Appleyard, M.; Thursz, M.; Carey, P. D.; Guillou, P. J.; Thomas, H. C.

1993-01-01

20

Anesthetic Considerations for Abdominal Wall Reconstructive Surgery  

PubMed Central

Anesthesia considerations for abdominal wall reconstruction (AWR) are numerous and depend upon the medical status of the patient and the projected procedure. Obesity, sleep apnea, hypertension, and cardiovascular disease are not uncommon in patients with abdominal wall defects; pulmonary functions and cardiac output can be affected by the surgical procedure. Patients with chronic obstructive pulmonary disease are also at a higher risk of coughing during the postoperative awakening process, which can compromise the reconstruction of the fascia. Given the increased complexity of the patients presenting for AWR, and the importance of the anesthesia for these specific procedures, it is important that surgeons are aware of the challenges that anesthesiologists face when treating these patients. Some of these challenges and their resolution are reviewed here.

Slabach, Rachel; Suyderhoud, Johan P.

2012-01-01

21

Heterotopic ossification of the abdominal wall  

PubMed Central

INTRODUCTION Heterotopic ossification is a rare, benign condition which occurs when bone develops in tissues that do not normally ossify. PRESENTATION OF CASE We herein report the case of a 73-year-old gentleman who underwent a laparotomy for a large splenic flexure tumour considered unresectable at initial intervention. Following delivery of chemotherapy, he was referred for a second opinion and the tumour with adjacent structures was removed at a subsequent laparotomy. A segment of abnormal hard tissue present in the abdominal wall was also excised. Histopathology revealed metaplastic bone deposition. DISCUSSION Heterotopic ossification may occur at various sites and is a recognised but exceedingly infrequent sequela of abdominal surgery. CONCLUSION This case highlights clinical, aetiological and histopathological features of this rare finding.

Hogan, Niamh M.; Caffrey, Emer; Curran, Stephanie; Sheehan, Margaret; Joyce, Myles R.

2012-01-01

22

Turbine airfoil with outer wall thickness indicators  

DOEpatents

A turbine airfoil usable in a turbine engine and including a depth indicator for determining outer wall blade thickness. The airfoil may include an outer wall having a plurality of grooves in the outer surface of the outer wall. The grooves may have a depth that represents a desired outer surface and wall thickness of the outer wall. The material forming an outer surface of the outer wall may be removed to be flush with an innermost point in each groove, thereby reducing the wall thickness and increasing efficiency. The plurality of grooves may be positioned in a radially outer region of the airfoil proximate to the tip.

Marra, John J; James, Allister W; Merrill, Gary B

2013-08-06

23

Remote revascularization of abdominal wall transplants using the forearm.  

PubMed

Primary abdominal wall closure following small bowel transplantation is frequently impossible due to contraction of the abdominal domain. Although abdominal wall transplantation was reported 10 years ago this, technique has not been widely adopted, partly due to its complexity, but largely because of concerns that storing the abdominal allograft until the end of a prolonged intestinal transplant procedure would cause severe ischemia-reperfusion injury. We report six cases of combined small bowel and abdominal wall transplantation where the ischemic time was minimized by remotely revascularizing the abdominal wall on the forearm vessels, synchronous to the intestinal procedure. When the visceral transplant was complete, the abdominal wall was removed from the forearm and revascularized on the abdomen (n?=?4), or used to close the abdomen while still vascularized on the forearm (n?=?2). Primary abdominal wall closure was achieved in all. Mean cold ischemia was 305?min (300-330?min), and revascularization on the arm was 50?min (30-60?min). Three patients had proven abdominal wall rejection, all treated successfully. Immediate revascularization of the abdominal wall allograft substantially reduces cold ischemia without imposing constraints on the intestinal transplant. Reducing storage time may also have benefits with respect to ischemia-reperfusion-related graft immunogenicity. PMID:24797611

Giele, H; Bendon, C; Reddy, S; Ramcharan, R; Sinha, S; Friend, P; Vaidya, A

2014-06-01

24

Spontaneous abdominal wall endometriosis: a case report.  

PubMed

Endometriosis is the presence of endometrial glands and stroma outside the uterus. Spontaneous abdominal wall endometriosis (AWE) is any ectopic endometrium found superficial to the peritoneum without the presence of any previous scar. Rarely, endometriosis represents a disease of specific interest to the general surgeon, on account of its extrapelvic localisations. We describe a case with spontaneous AWE presenting as a painful mass with cyclic symptoms. A 28-year-old woman presented to the day-surgery division of our department, suffering from a painful mass in the left lower abdominal quadrant. A mobile mass of 5 x 4 cm was identified. The initial diagnosis was lipoma and excision was planned. During the operation two masses were spotted, very close to one another, and were excised within healthy limits. Pathology revealed endometrial glands surrounded by a disintegrating mantle of endometrial stroma and fibrous scar tissue in which there was a scattering of leucocytes. The woman had no scars. She was discharged from hospital after 2 hours. Two years after the excision she is free of disease and no recurrence has been observed. Spontaneous AWE is rare, accounting for 20% of all AWEs. The triad ; mass, pain and cyclic symptomatology helps in the diagnosis, but unfortunately it is not present in all cases. Spontaneous endometriomas are usually diagnosed by pathology and the treatment of choice is surgical excision. PMID:20184068

Papavramidis, Th S; Sapalidis, K; Michalopoulos, N; Karayanopoulou, G; Raptou, G; Tzioufa, V; Kesisoglou, I; Papavramidis, S T

2009-01-01

25

Tensor fascia lata musculocutaneous flap for abdominal wall reconstruction  

SciTech Connect

We report a case of abdominal wall reconstruction following excision of irradiated skin and a ventral hernia. A very large tensor fascia lata musculocutaneous flap was used with good results. The anatomical features of this flap make it an excellent method of abdominal wall reconstruction.

Peled, I.J.; Kaplan, H.Y.; Herson, M.; Wexler, M.R.

1983-08-01

26

A Traumatic Abdominal Wall Hernia Repair: A Laparoscopic Approach  

PubMed Central

Background: Traumatic abdominal wall hernias from blunt trauma usually occur as a consequence of motor vehicle collisions where the force is tangential, sudden, and severe. Although rare, these hernias can go undetected due to preservation of the skin overlying the hernia defect. Open repairs can be challenging and unsuccessful due to avulsion of muscle directly from the iliac crest, with or without bone loss. A laparoscopic approach to traumatic abdominal wall hernia can aid in the delineation of the hernia and allow for a safe and effective repair. Case Description: A 36-year-old female was admitted to our Level 1 trauma center with a traumatic abdominal wall hernia located in the right flank near the iliac crest after being involved in a high-impact motor vehicle collision. Computed tomography and magnetic resonance imaging of the abdomen revealed the presence of an abdominal wall defect that was unapparent on physical examination. The traumatic abdominal wall hernia in the right flank was successfully repaired laparoscopically. One-year follow-up has shown no sign of recurrence. Discussion: A traumatic abdominal wall hernia rarely presents following blunt trauma, but should be suspected following a high-impact motor vehicle collision. Frequently, repair is complicated by the need to have fixation of mesh to bony landmarks (eg, iliac crest). In spite of this challenge, the laparoscopic approach with tension-free mesh repair of a traumatic abdominal wall hernia can be accomplished successfully using an approach similar to that taken for laparoscopic inguinal hernia repair.

Wilson, Kenneth L.; Rosser, James C.

2012-01-01

27

Abdominal wall paresis as a complication of laparoscopic surgery  

Microsoft Academic Search

Purpose  Abdominal wall nerve injury as a result of trocar placement for laparoscopic surgery is rare. We intend to discuss causes\\u000a of abdominal wall paresis as well as relevant anatomy.\\u000a \\u000a \\u000a \\u000a Methods  A review of the nerve supply of the abdominal wall is illustrated with a rare case of a patient presenting with paresis of\\u000a the internal oblique muscle due to a trocar

G. H. van Ramshorst; G.-J. Kleinrensink; J. J. Hermans; T. Terkivatan; J. F. Lange

2009-01-01

28

Abdominal wall haematoma in the obese: a dangerous phenomenon.  

PubMed

We report the case of a 59-year-old obese female who developed an abdominal wall haematoma during administration of prophylactic clexane. Compared with the non-obese, the subcutaneous tissue of the obese is considered dysfunctional and has a different vascular structure and extra-cellular matrix composition. While the development of an abdominal wall haematoma is relatively uncommon, when they occur they can have fatal consequences. The altered subcutaneous tissue environment in the obese attenuates the normal external compression of an abdominal wall haematoma and as a result the obese are at greater risk of haemorrhage. PMID:24964461

Goldstein, Jerome M; Sebire, Dale

2013-01-01

29

Malignant granular cell tumor of the abdominal wall.  

PubMed

The granular cell tumor is an uncommon tumor that usually appears as a solitary small nodular growth and runs a benign course. It occurs widely throughout the body, but is rarely described in the abdominal wall. The authors report a case of malignant granular cell tumor which was arising in anterior abdominal wall of a 67-year-old woman. Malignant variant is rare and the abdominal wall site is extremely uncommon. Regarding this clinical case and the literature the authors purpose to review the criteria of malignancy. PMID:16259279

Chelly, I; Bellil, K; Mekni, A; Bellil, S; Belhadjsalah, M; Kchir, N; Haouet, S; Zitouna, M M

2005-06-01

30

Ultrasound of the abdominal wall: what lies beneath?  

PubMed

Clinically equivocal abdominal wall lesions often pose diagnostic dilemmas for clinicians. It can be equally challenging to appreciate the nature of abdominal wall lesions found incidentally on abdominal ultrasound examinations. Ultrasound is a non-ionizing, cheap, and easily accessible investigation for such lesions. It is widely used and has the added advantage of being a dynamic investigation. However, imaging with ultrasound is operator-dependent and relies on technical skills. It is important to understand the imaging of normal anatomy and to be familiar with the imaging appearance of lesions. We present a review of various lesions seen during ultrasound examinations of the abdominal wall or as incidental findings on abdominal ultrasound. PMID:22854266

Jain, N; Goyal, N; Mukherjee, K; Kamath, S

2013-01-01

31

Desmoid tumor of the abdominal wall: a case report  

PubMed Central

Introduction Desmoid tumors are rare lesions without any metastatic potential but a strong tendency to invade locally and to recur. These tumors are associated with women of fertile age, especially during and after pregnancy. Case presentation The case of a desmoid tumor of the anterior abdominal wall in a 40-year-old Caucasian man with no relevant family history is presented, describing its appearance on computed tomography and ultrasonography. The patient, who presented with a painless mass in the left anterolateral abdomen, had a history of previous urgent abdominal surgery after a shotgun injury two years earlier. Radical resection of the affected abdominal wall musculature was performed, and the defect was reconstructed with polypropylene mesh. Conclusion The diagnosis of desmoid tumor should be strongly considered even in male patients with an abdominal mass and a history of previous abdominal surgery. The goal of its treatment is complete tumor excision and avoidance of the development of complications such as hernia.

2011-01-01

32

Wandering ascaris coming out through the abdominal wall.  

PubMed

A rare case of ascaris coming out through the anterior abdominal wall is reported here. A 40-year-old female had undergone dilatation and curettage by a quack. On the second day she presented with presented with features of peritonitis. She was explored. Resection anastomosis of the ileum was done for multiple perforations of the ileum. Patient developed a fistula in the anterior abdominal wall which was draining bile-colored fluid. On the 12(th) postoperative day a 10-cm-long worm was seen coming out through the fistulous tract which was found to be Ascaris lumbricoids. Ascaris lumbricoids can lead to many complications ranging from worm colic to intestinal obstruction, volvulus, peritonitis, pancreatitis, cholangiohepatitis, liver abscess and many more. Worm has been reported to come out through mouth, nostrils, abdominal drains, T-tubes etc. But ascaris coming out through the anterior abdominal wall is very rare hence reported here. PMID:23930192

Wani, Mohd L; Rather, Ajaz A; Parray, Fazl Q; Ahangar, Abdul G; Bijli, Akram H; Irshad, Ifat; Nayeem-Ul-Hassan; Khan, Tahir S

2013-06-01

33

Wandering Ascaris Coming Out Through the Abdominal Wall  

PubMed Central

A rare case of ascaris coming out through the anterior abdominal wall is reported here. A 40-year-old female had undergone dilatation and curettage by a quack. On the second day she presented with presented with features of peritonitis. She was explored. Resection anastomosis of the ileum was done for multiple perforations of the ileum. Patient developed a fistula in the anterior abdominal wall which was draining bile-colored fluid. On the 12th postoperative day a 10-cm-long worm was seen coming out through the fistulous tract which was found to be Ascaris lumbricoids. Ascaris lumbricoids can lead to many complications ranging from worm colic to intestinal obstruction, volvulus, peritonitis, pancreatitis, cholangiohepatitis, liver abscess and many more. Worm has been reported to come out through mouth, nostrils, abdominal drains, T-tubes etc. But ascaris coming out through the anterior abdominal wall is very rare hence reported here.

Wani, Mohd L; Rather, Ajaz A.; Parray, Fazl Q.; Ahangar, Abdul G.; Bijli, Akram H.; Irshad, Ifat; Nayeem-Ul-Hassan; Khan, Tahir S.

2013-01-01

34

Massive ventral hernias: role of tissue expansion in abdominal wall restoration following abdominal compartment syndrome.  

PubMed

Massive ventral hernias may result from a variety of clinical situations. One such clinical situation, a common problem in trauma patients, is abdominal compartment syndrome. Abdominal compartment syndrome frequently results in a massive abdominal defect when primary closure after surgical decompression is not possible. We offer a technique for repairing these massive ventral hernias by first expanding the lateral abdominal wall muscles, fasciae, and skin with tissue expanders and then closing the defect with elements of the "components separation" method. Additionally we present other clinical situations resulting in a massive ventral hernia that were repaired using this technique. PMID:12013296

Admire, Anthony A; Dolich, Matthew O; Sisley, Amy C; Samimi, Kian J

2002-05-01

35

The biology of hernias and the abdominal wall  

Microsoft Academic Search

The fundamental mechanism for hernia formation is loss of the mechanical integrity of abdominal wall structural tissue that\\u000a results in the inability to offset and contain intra-abdominal forces during valsalva and loading of the torso. There is evidence\\u000a that genetic or systemic extracellular matrix disorders may predispose patients to hernia formation. There is also evidence\\u000a that acute laparotomy wound failure

Michael G. Franz

2006-01-01

36

WSES guidelines for emergency repair of complicated abdominal wall hernias.  

PubMed

Emergency repair of complicated abdominal hernias is associated with poor prognosis and a high rate of post-operative complications.A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bergamo in July 2013, during the 2nd Congress of the World Society of Emergency Surgery with the goal of defining recommendations for emergency repair of abdominal wall hernias in adults. This document represents the executive summary of the consensus conference approved by a WSES expert panel. PMID:24289453

Sartelli, Massimo; Coccolini, Federico; van Ramshorst, Gabrielle H; Campanelli, Giampiero; Mandalà, Vincenzo; Ansaloni, Luca; Moore, Ernest E; Peitzman, Andrew; Velmahos, George; Moore, Fredrick Alan; Leppaniemi, Ari; Burlew, Clay Cothren; Biffl, Walter; Koike, Kaoru; Kluger, Yoram; Fraga, Gustavo P; Ordonez, Carlos A; Di Saverio, Salomone; Agresta, Ferdinando; Sakakushev, Boris; Gerych, Igor; Wani, Imtiaz; Kelly, Michael D; Gomes, Carlos Augusto; Faro, Mario Paulo; Taviloglu, Korhan; Demetrashvili, Zaza; Lee, Jae Gil; Vettoretto, Nereo; Guercioni, Gianluca; Tranà, Cristian; Cui, Yunfeng; Kok, Kenneth Yy; Ghnnam, Wagih M; Abbas, Ashraf El-Sayed; Sato, Norio; Marwah, Sanjay; Rangarajan, Muthukumaran; Ben-Ishay, Offir; Adesunkanmi, Abdul Rashid K; Segovia Lohse, Helmut Alfredo; Kenig, Jakub; Mandalà, Stefano; Patrizi, Andrea; Scibé, Rodolfo; Catena, Fausto

2013-01-01

37

Improving the Efficiency of Abdominal Aortic Aneurysm Wall Stress Computations  

PubMed Central

An abdominal aortic aneurysm is a pathological dilation of the abdominal aorta, which carries a high mortality rate if ruptured. The most commonly used surrogate marker of rupture risk is the maximal transverse diameter of the aneurysm. More recent studies suggest that wall stress from models of patient-specific aneurysm geometries extracted, for instance, from computed tomography images may be a more accurate predictor of rupture risk and an important factor in AAA size progression. However, quantification of wall stress is typically computationally intensive and time-consuming, mainly due to the nonlinear mechanical behavior of the abdominal aortic aneurysm walls. These difficulties have limited the potential of computational models in clinical practice. To facilitate computation of wall stresses, we propose to use a linear approach that ensures equilibrium of wall stresses in the aneurysms. This proposed linear model approach is easy to implement and eliminates the burden of nonlinear computations. To assess the accuracy of our proposed approach to compute wall stresses, results from idealized and patient-specific model simulations were compared to those obtained using conventional approaches and to those of a hypothetical, reference abdominal aortic aneurysm model. For the reference model, wall mechanical properties and the initial unloaded and unstressed configuration were assumed to be known, and the resulting wall stresses were used as reference for comparison. Our proposed linear approach accurately approximates wall stresses for varying model geometries and wall material properties. Our findings suggest that the proposed linear approach could be used as an effective, efficient, easy-to-use clinical tool to estimate patient-specific wall stresses.

Zelaya, Jaime E.; Goenezen, Sevan; Dargon, Phong T.; Azarbal, Amir-Farzin; Rugonyi, Sandra

2014-01-01

38

Improving the efficiency of abdominal aortic aneurysm wall stress computations.  

PubMed

An abdominal aortic aneurysm is a pathological dilation of the abdominal aorta, which carries a high mortality rate if ruptured. The most commonly used surrogate marker of rupture risk is the maximal transverse diameter of the aneurysm. More recent studies suggest that wall stress from models of patient-specific aneurysm geometries extracted, for instance, from computed tomography images may be a more accurate predictor of rupture risk and an important factor in AAA size progression. However, quantification of wall stress is typically computationally intensive and time-consuming, mainly due to the nonlinear mechanical behavior of the abdominal aortic aneurysm walls. These difficulties have limited the potential of computational models in clinical practice. To facilitate computation of wall stresses, we propose to use a linear approach that ensures equilibrium of wall stresses in the aneurysms. This proposed linear model approach is easy to implement and eliminates the burden of nonlinear computations. To assess the accuracy of our proposed approach to compute wall stresses, results from idealized and patient-specific model simulations were compared to those obtained using conventional approaches and to those of a hypothetical, reference abdominal aortic aneurysm model. For the reference model, wall mechanical properties and the initial unloaded and unstressed configuration were assumed to be known, and the resulting wall stresses were used as reference for comparison. Our proposed linear approach accurately approximates wall stresses for varying model geometries and wall material properties. Our findings suggest that the proposed linear approach could be used as an effective, efficient, easy-to-use clinical tool to estimate patient-specific wall stresses. PMID:25007052

Zelaya, Jaime E; Goenezen, Sevan; Dargon, Phong T; Azarbal, Amir-Farzin; Rugonyi, Sandra

2014-01-01

39

On thick domain walls in general relativity  

NASA Technical Reports Server (NTRS)

Planar scalar field configurations in general relativity differ considerably from those in flat space. It is shown that static domain walls of finite thickness in curved space-time do not possess a reflection symmetry. At infinity, the space-time tends to the Taub vacuum on one side of the wall and to the Minkowski vacuum (Rindler space-time) on the other. Massive test particles are always accelerated towards the Minkowski side, i.e., domain walls are attractive on the Taub side, but repulsive on the Minkowski side (Taub-vacuum cleaner). It is also proved that the pressure in all directions is always negative. Finally, a brief comment is made concerning the possibility of infinite, i.e., bigger than horizon size, domain walls in our universe. All of the results are independent of the form of the potential V(phi) greater than or equal to 0 of the scalar field phi.

Goetz, Guenter; Noetzold, Dirk

1989-01-01

40

[Desmoid tumors of the abdominal wall: three cases].  

PubMed

Desmoids tumors are rare. They often develop from the fascia and muscles of the abdominal wall. They are considered as benign, but endowed with local aggressiveness. Treatment is primarily surgical. Complete resection with large safety margins and sometimes complex reconstruction is necessary to reduce the risk of local reccurrence. WE report three cases of histology proven desmoids tumors of the abdominal wall treated between 2000 and 2007. Etiologic factors, diagnosis, surgical management and adjuvant therapy in case of incomplete resection or reccurrence are discussed. PMID:20143748

Soufi, M; Lahlou, M K; Bensaid, M; Messrouri, R; Benamer, S; Essadel, A; Mdaghri, J; Mohammadine, E; Taghy, A; Settaf, A; Chad, B

2009-12-01

41

Transient abdominal wall deformity in an infant Blaming the caudal?  

PubMed

Locoregional anesthesia is an important aspect of perioperative analgesia. It decreases requirements for anesthetic agents and opioids, decreases the surgical stress response, and provides postoperative analgesia. Nonetheless, pediatric patients, especially infants, demonstrate specificities towards regional anesthesia techniques, as an increased sensitivity to local anesthetics (LA) and a higher ease of LA spread especially when using blocks that rely on the volume of LA and its spread as those used for abdominal wall analgesia or caudal. Thus, we present a case of transient abdominal wall deformity following caudal anesthesia in an infant. PMID:24666789

Tosetti, Sylvain; Frigon, Chantal

2014-06-01

42

Ultrasonography and computed tomography of inflammatory abdominal wall lesions  

SciTech Connect

Twenty-four patients with inflammatory lesions of the abdominal wall were examined by ultrasonography. Nine of these patients underwent computed tomographic (CT) scanning as well. Both ultrasonography and CT clearly delineated the exact location and extent of abdominal wall abscesses. Abscesses were easily differentiated from cellulitis or phlegmon with ultrasound. The peritoneal line was more clearly delineated on ultrasonograms than on CT scans; abscesses were also more distinct on the ultrasonograms because of their low echogenicity compared with the surrounding structures. Gas bubbles, fat density with specific low attenuation values, and underlying inflamed bowel loops in obese patients with Crohn's disease were better delineated by CT.

Yeh, H.C.; Rabinowitz, J.G.

1982-09-01

43

High accuracy wall thickness loss monitoring  

NASA Astrophysics Data System (ADS)

Ultrasonic inspection of wall thickness in pipes is a standard technique applied widely in the petrochemical industry. The potential precision of repeat measurements with permanently installed ultrasonic sensors however significantly surpasses that of handheld sensors as uncertainties associated with coupling fluids and positional offsets are eliminated. With permanently installed sensors the precise evaluation of very small wall loss rates becomes feasible in a matter of hours. The improved accuracy and speed of wall loss rate measurements can be used to evaluate and develop more effective mitigation strategies. This paper presents an overview of factors causing variability in the ultrasonic measurements which are then systematically addressed and an experimental setup with the best achievable stability based on these considerations is presented. In the experimental setup galvanic corrosion is used to induce predictable and very small wall thickness loss. Furthermore, it is shown that the experimental measurements can be used to assess the effect of reduced wall loss that is produced by the injection of corrosion inhibitor. The measurements show an estimated standard deviation of about 20nm, which in turn allows us to evaluate the effect and behaviour of corrosion inhibitors within less than an hour.

Gajdacsi, Attila; Cegla, Frederic

2014-02-01

44

Gas turbine bucket wall thickness control  

DOEpatents

A core for use in casting a turbine bucket including serpentine cooling passages is divided into two pieces including a leading edge core section and a trailing edge core section. Wall thicknesses at the leading edge and the trailing edge of the turbine bucket can be controlled independent of each other by separately positioning the leading edge core section and the trailing edge core section in the casting die. The controlled leading and trailing edge thicknesses can thus be optimized for efficient cooling, resulting in more efficient turbine operation.

Stathopoulos, Dimitrios (Glenmont, NY); Xu, Liming (Greenville, SC); Lewis, Doyle C. (Greer, SC)

2002-01-01

45

Abdominal wall trigger point case study.  

PubMed

Myofascial trigger points (TrPs) are posited to be an element in the etiology of both musculoskeletal and visceral pain. However, the recognition of TrPs as a causative factor in a patient's pain presentation varies amongst physicians and therapists. When myofascial pain syndrome is responsible for a patient's condition and is not recognized by the patient's medical advisors, the patient may be put through a plethora of testing procedures to find the cause of the patient's pain, and prescribed medications in an effort to treat the patient's symptoms. The case review presented here involves a patient with severe anterior abdominal pain, with a history of Crohn's disease, who experienced a long and difficult medical process before a diagnosis of myofascial pain syndrome was made. PMID:23561860

Muscolino, Joseph E

2013-04-01

46

[Malignant transformation of abdominal wall endometriosis: a new case report].  

PubMed

Cancer arising in abdominal wall endometriosis is a rare event, hindering diagnosis and making management uncertain. A cesarean section scar is generally at the origin of the disease. We report the case of a 45-year-old woman, with a past medical history of cesarean deliveries, complaining of a repeat abdominal wall endometriosis which transformed into a clear-cell carcinoma. Outcome was rapidly fatal. Compared with endometriosis-associated ovarian carcinoma, the prognosis of this abdominal scar complication is poor. In the literature, survival rate reaches only 57% after a short follow-up of 20 months. Clear-cell carcinoma is the most common histological subtype, followed by endometrioid carcinoma. Radical surgery is the main treatment. Good technique and proper care during cesarean section may help in preventing this endometriosis complication. PMID:16575366

Sergent, F; Baron, M; Le Cornec, J-B; Scotté, M; Mace, P; Marpeau, L

2006-04-01

47

Extragastrointestinal stromal tumour of the abdominal wall - a case report.  

PubMed

Stromal tumours occurring in areas other than the GastroIntestinal Tract (GIT) are known as Extra GastroIntestinal Stromal Tumours (EGISTs). They usually arise in the mesentery, omentum or retroperitoneum, while EGISTs which occur in the abdominal wall are very rare. Both gastrointestinal stromal tumours (GISTs) and EGISTs are histologically and immunophenotypically similar. We are reporting a case of EGIST, which occurred in the anterior abdominal wall in a twenty five-year-old female patient. The tumour was present in the right loin and imaging studies suggested that it was a desmoid tumour. It was surgically excised by doing an abdominal wall mesh repair. The histological examinations revealed a tumour with spindle cell morphology, with <2 mitoses per 50 High Power Field (HPF) and no necrosis, with tumour free margins. Immunohistochemistry was strongly positive for CD117 and Smooth Muscle Actin (SMA), while it was negative for ?-catenin and S100. The patient is well post operatively and is on close follow up. EGISTs should be considered in the differential diagnosis of mesenchymal tumours which occur in the abdominal wall, inspite of their rarity, as the high risk patients may need Imatinib chemotherapy. PMID:24551695

Kumar, A Sathish Selva; Padmini, R; Veena, G; Murugesan, N

2013-12-01

48

Malignant Schwannoma of Anterior Abdominal Wall: Report of a Case  

PubMed Central

Malignant schwannoma of the anterior abdominal wall nerves is extremely rare. Malignant peripheral nerve sheath tumors (MPNST) represent approximately 10% of all soft tissue sarcomas and it is found in 4% of patients with neurofibromatosis 1. We present a case of malignant schwannoma in a 28-year-old female patient with neurofibromatosis 1. She presented with a painful mass in the right upper quadrant of her abdomen. The tumor location was in the abdominal wall in explorative laparatomy and malignant schwannoma was diagnosed in pathologic assessment. The tumor recurred in 3 months and computed tomography showed two masses in the right side of abdominopelvic cavity. Thereafter, second complete surgical resection was performed and pathologic finding was the same. In spite of administering chemotherapy after second surgery,the tumor recurred and magnetic resonance imaging finding showed a huge heterogeneously enhancing mass with adhesion to the inner side of the abdominal wall. The patient died because of acute respiratory failure due to multiple bilateral pulmonary metastases. Tumor location and rapid recurrence was unique in our patient. Keywords Malignant peripheral nerve sheath tumor; Malignant schwannoma; Abdominal wall

Khorgami, Zhamak; Nasiri, Shirzad; Rezakhanlu, Freshteh; Sodagari, Nassim

2009-01-01

49

Reconstruction of extensive abdominal wall defect using an eccentric perforator-based pedicled anterolateral thigh flap: a case report.  

PubMed

Reconstruction of extensive abdominal wall defects is a challenge for reconstructive surgeons. In this report, a case of reconstruction of a large abdominal wall defect using an eccentric perforator-based pedicled anterolateral thigh (ALT) flap is presented. A 30-year-old man presented with recurrent desmoid-type fibromatosis in the abdominal wall. The recurrent tumor was radically excised, and the en bloc excision resulted in a full-thickness, large abdominal wall defect (25 cm × 20 cm). An eccentric perforator-based pedicled ALT flap, including wide fascial extension, was transferred to the abdominal defect; fascial portions were sutured to the remnant abdominal fascia. Plication of the fascia along the sutured portion was performed to relieve the skin tension between the flap and the marginal skin of the abdominal defect. Eight months after surgery, the reconstructed abdomen had an acceptable esthetic appearance without tumor recurrence or hernia. The use of an eccentric perforator-based pedicled ALT flap may be an alternative method for the reconstruction of extensive abdominal wall defects. PMID:23836365

Jang, Joonchul; Jeong, Seong-Ho; Han, Seung-Kyu; Kim, Woo-Kyung

2013-09-01

50

Simulation of ultrasonic pulse propagation through the abdominal wall.  

PubMed

Ultrasonic pulse propagation through the abdominal wall has been simulated using a model for two-dimensional propagation through anatomically realistic tissue cross sections. The time-domain equations for wave propagation in a medium of variable sound speed and density were discretized to obtain a set of coupled finite-difference equations. These difference equations were solved numerically using a two-step MacCormack scheme that is fourth-order accurate in space and second-order accurate in time. The inhomogeneous tissue of the abdominal wall was represented by two-dimensional matrices of sound speed and density values. These values were determined by processing scanned images of abdominal wall cross sections stained to identify connective tissue, muscle, and fat, each of which was assumed to have a constant sound speed and density. The computational configuration was chosen to simulate that of wavefront distortion measurements performed on the same specimens. Qualitative agreement was found between those measurements and the results of the present computations, indicating that the computational model correctly depicts the salient characteristics of ultrasonic wavefront distortion in vivo. However, quantitative agreement was limited by the two-dimensionality of the computation and the absence of detailed tissue microstructure. Calculations performed using an asymptotic straight-ray approximation showed good agreement with time-shift aberrations predicted by the full-wave method, but did not explain the amplitude fluctuations and waveform distortion found in the experiments and the full-wave calculations. Visualization of computed wave propagation within tissue cross sections suggests that amplitude fluctuations and waveform distortion observed in ultrasonic propagation through the abdominal wall are associated with scattering from internal inhomogeneities such as septa within the subcutaneous fat. These observations, as well as statistical analysis of computed and observed amplitude fluctuations, suggest that weak fluctuation models do not fully describe ultrasonic wavefront distortion caused by the abdominal wall. PMID:9265762

Mast, T D; Hinkelman, L M; Orr, M J; Sparrow, V W; Waag, R C

1997-08-01

51

[PAUL procedure. A new biocompatible concept for the therapy of congenital abdominal wall defects].  

PubMed

Treatment of small congenital abdominal wall defects (e.g. omphalocele and gastroschisis) can be performed by direct closure. In large defects non-resorbable artificial materials (e.g. Gore-Tex) are necessary to close the fascia. The aim of this study was to find out whether a new procedure, the PAUL pocedure, might be suitable for the treatment of large abdominal wall defects. A full thickness abdominal wall defect was created in young Wistar Rats. These defects were then closed by implantation of a 1x2 cm sized piece of PTFE (Dual-Mesh), a polypropylene mesh (Prolene(R)) or by using the PAUL procedure. Over a period of 6 weeks no wound infections or hernias were monitored. In contrast to PTFE the PAUL procedure showed only minimal adhesion to the intestine and a high stability of the implanted material. A xenogenic extracellular matrix, such as that used in the PAUL procedure, may induce an immune response, which is comparable with a remodeling reaction rather than rejection. Based on these good results a large animal model study (Goettinger mini-piglets) was performed. No wound infections or hernias could be observed throughout the experiment. Control laparoscopy after 3, 6, 9, and 12 months showed only minimal adhesion to the intestine. Our results indicate that the PAUL procedure can be used easily and successfully for the therapy of congenital abdominal wall defects. PMID:19756429

Meyer, T; Seifert, A; Meyer, B; Ulrichs, K; Germer, C-T

2010-03-01

52

Complex abdominal wall repair using a porcine dermal matrix.  

PubMed

Management of complex abdominal defects remains a significant challenge for many surgeons, especially in contaminated fields. Currently, available biosynthetic grafts include human cadaveric dermis (AlloDerm), porcine dermal (Permacol and Strattice), and submucosal (Surgisis) sources. All these grafts are composed of an acellular collagen scaffold to provide a bridge for tissue incorporation and neovascularization. The authors describe a case report of a woman who required dual mesh explantation and successive reparative surgery using a porcine dermal matrix for a complex and infected abdominal wound. Twelve months postdischarge the patient remains well, she is pain free, and she returned home to full activities with complete wound closure and without any evidence of residual or recurrent hernia. The patient was satisfied with her cosmetic results. In conclusion, the authors' experience shows that the use of Permacol, a porcine dermal matrix, has been successful in treating an infected abdomen and a vast abdominal wall defect. PMID:22006210

Gentile, Pietro; Colicchia, Gianfranco Marcello; Nicoli, Fabio; Cervelli, Giulio; Curcio, Cristiano Beniamino; Brinci, Lorenzo; Cervelli, Valerio

2013-12-01

53

Massive abdominal-wall hernia reconstruction with expanded external/internal oblique and transversalis musculofascia.  

PubMed

We describe a technique for expansion and primary closure of massive and large recalcitrant abdominal-wall hernias in the middle and lower abdomen utilizing expanders placed in the lateral abdominal wall between the external oblique and the deeper complex of the internal oblique and transversalis fasciae. Since this technique describes expansion of the lateral abdominal wall, insertion incisions are made in the lateral abdominal wall away from the primary zone of injury surrounding the abdominal hernia and without interrupting the blood supply or innervation to the abdominal-wall muscle, fascia, or skin. This technique, described in four patients with massive abdominal-wall hernias, has been used successfully for primary closure with vascularized autogenous abdominal-wall fascia, obviating the need for interposition of prosthetic material or extraabdominal flaps. PMID:9252598

Jacobsen, W M; Petty, P M; Bite, U; Johnson, C H

1997-08-01

54

Clear Cell Adenocarcinoma Arising from Abdominal Wall Endometriosis  

PubMed Central

Endometriosis is a frequent benign disorder. Malignancy arising in extraovarian endometriosis is a rare event. A 49-year-old woman is presented with a large painful abdominal wall mass. She underwent a myomectomy, 20 years before, for uterus leiomyoma. Computed tomography suggested that this was a desmoid tumor and she underwent surgery. Histological examination showed a clear cell adenocarcinoma associated with endometriosis foci. Pelvic ultrasound, computed tomography, and endometrial curettage did not show any malignancy or endometriosis in the uterus and ovaries. Adjuvant chemotherapy was recommended, but the patient was lost to follow up. Six months later, she returned with a recurrence of the abdominal wall mass. She was given chemotherapy and then she was reoperated.

Achach, Thouraya; Rammeh, Soumaya; Trabelsi, Amel; Ltaief, Rached; Ben Abdelkrim, Soumaya; Mokni, Moncef; Korbi, Sadok

2008-01-01

55

Report of Three Cases of Unusual Anterior Abdominal Wall Defects in Fallujah General Hospital During the Year 2010  

PubMed Central

Abdominal wall defects occur when the normal sequence of the gastro intestinal tract development is interrupted. Gastroschisis represents a herniation of abdominal contents through a paramedian full-thickness abdominal wall fusion defect without involving the umbilical cord. Evisceration usually only contains intestinal loops and has no surrounding membrane unlike omphalocoele. It is unusual for a newborn with gastroschisis to have other serious birth defects. Neonates with gastroschisis have better prognosis than those with omphalocele. Very rarely is gastroschisis associated with herniation of other organs, and their presence makes the prognosis worse. I report three cases of unusual anterior abdominal wall defects during the year 2010, each having specific associated abnormalities. One was stillborn, and the other two died shortly after delivery.

Alaani, Samira

2012-01-01

56

The Role of Stem Cells in Abdominal Wall Repair  

Microsoft Academic Search

\\u000a Incisional hernias fundamentally result from acute laparotomy wound failure. Evidence supports the mechanism that gaps in\\u000a the early laparotomy repair progress to clinical incisional hernias [1, 2]. The linea alba is especially at risk for acute wound failure because of the low number of repair fibroblasts and relative\\u000a ischemia at this location of the abdominal wall. Laparotomy wound-healing failure occurs

M. G. Franz

57

Blood vessel matrix: a new alternative for abdominal wall reconstruction  

Microsoft Academic Search

Background  Biologic matrices offer a new approach to the management of abdominal wall defects when the use of other foreign material\\u000a is not ideal. A member of our team (GEA) developed a biological decellularized matrix generated from harvested blood vessels\\u000a of swine blood vessel matrix (BVMx). The aim of our study was to investigate whether this novel collagen-based biological\\u000a matrix is

C. F. Bellows; W. Jian; M. K. McHale; D. Cardenas; J. L. West; S. P. Lerner; G. E. Amiel

2008-01-01

58

Traumatic handlebar hernia: A rare abdominal wall hernia  

Microsoft Academic Search

Traumatic abdominal wall herniation (TAWH) caused by direct trauma from bicycle handlebars are rare. There are only 21 reported cases of handlebar hernias. An 11-year-old boy presented to the emergency room soon after falling from his bicycle and hitting his right lower quadrant on the handlebars. The patient’s vital signs and initial laboratory studies were normal. Physical exam showed a

J. Goliath; V. Mittal; J. McDonough

2004-01-01

59

"Acute postoperative open abdominal wall": Nosological concept and treatment implications  

PubMed Central

The so-called “burst abdomen” has been described for many years and is a well-known clinical condition, whereas the concept of the “open abdomen” is relatively new. In clinical practice, both nosological entities are characterized by a complex spectrum of symptoms apparently disconnected, which in many cases poses a great challenge for surgical repair. In order to assess the management of these disorders in a more comprehensive and integral fashion, the concept of “acute postoperative open abdominal wall” (acute POAW) is presented, which in turn can be divided into “intentional” or planned acute POAW and “unintentional” or unplanned POAW. The understanding of the acute POAW as a single clinical process not only allows a better optimization of the therapeutic approach in the surgical repair of abdominal wall-related disorders, but also the stratification and collection of data in different patient subsets, favoring a better knowledge of the wide spectrum of conditions involved in the surgical reconstruction of the abdominal wall.

Lopez-Cano, Manuel; Pereira, Jose A; Armengol-Carrasco, Manuel

2013-01-01

60

"Acute postoperative open abdominal wall": Nosological concept and treatment implications.  

PubMed

The so-called "burst abdomen" has been described for many years and is a well-known clinical condition, whereas the concept of the "open abdomen" is relatively new. In clinical practice, both nosological entities are characterized by a complex spectrum of symptoms apparently disconnected, which in many cases poses a great challenge for surgical repair. In order to assess the management of these disorders in a more comprehensive and integral fashion, the concept of "acute postoperative open abdominal wall" (acute POAW) is presented, which in turn can be divided into "intentional" or planned acute POAW and "unintentional" or unplanned POAW. The understanding of the acute POAW as a single clinical process not only allows a better optimization of the therapeutic approach in the surgical repair of abdominal wall-related disorders, but also the stratification and collection of data in different patient subsets, favoring a better knowledge of the wide spectrum of conditions involved in the surgical reconstruction of the abdominal wall. PMID:24392182

López-Cano, Manuel; Pereira, José A; Armengol-Carrasco, Manuel

2013-12-27

61

Fetal aorta wall inflammation in ultrasound-detected aortic intima/media thickness and growth retardation.  

PubMed

Several studies have reported that fetuses with intrauterine growth restriction (IUGR) and infants with low birth weight present increased intima/media thickness (aIMT) of the abdominal aorta wall compared with fetuses and infants appropriate for gestational age (AGA). Evidence suggested that aIMT might be related to inflammation, probably indicating a very early stage of future adulthood disease, such as atherosclerosis. We aimed to investigate histological findings in the abdominal aorta wall of one IUGR stillbirth in which ultrasound had detected aIMT. Microscopy observations of the abdominal aorta wall confirmed the intima thickening and detected condensation of the elastic fibers forming an evident internal elastic membrane and presence of inflammatory elements, such as macrophages, activated endothelial cells, and fibroblastoid cells. The present study highlights that IUGR associated with aIMT is related to inflammation, which might represent a very early sign of future adult lesions. PMID:21742382

Lo Vasco, Vincenza Rita; Salmaso, Roberto; Zanardo, Vincenzo; Businaro, Rita; Visentin, Silvia; Trevisanuto, Daniele; Cosmi, Erich

2011-09-01

62

Distribution of Wall Stress in Abdominal Aortic Aneurysm (AAA)  

NASA Astrophysics Data System (ADS)

Abdominal aortic aneurysm (AAA) rupture is believed to occur when the mechanical stress acting on the wall exceeds the strength of the wall tissue. Therefore, knowledge of the AAA wall stress distribution could be useful in assessing its risk of rupture. In our research, a finite element analysis was used to determine the wall stresses both in idealized models and in a real clinical model in which the aorta was considered isotropic with nonlinear material properties and was loaded with a given pressure. In the idealized models, both maximum diameter and asymmetry were found to have substantial influence on the distribution of the wall stress. The thrombus inside the AAA was also found to help protecting the walls from high stresses. Using CT scans of the AAA, the actual geometry of the aneurysm was reconstructed and we found that wall tension increases on the flatter surface (typically corresponds to the posterior surface) and at the inflection points of the bulge. In addition to the static analysis, we also performed simulations of the effect of unsteady pressure wave propagation inside the aneurysm.

Lasheras, Juan

2005-11-01

63

New portable pipe wall thickness measuring technique  

NASA Astrophysics Data System (ADS)

One of the biggest inspection challenges facing many of the process industries; namely the petrochemical, refining, fossil power, and pulp and paper industries is: How to effectively examine their insulated piping? While there are a number of failure mechanisms involved in various process piping systems, piping degradation through corrosion and erosion are by far the most prevalent. This degradation can be in the form of external corrosion under insulation, internal corrosion through a variety of mechanisms, and internal erosion caused by the flow of the product through the pipe. Refineries, chemical plants and electrical power plants have MANY thousands of miles of pipe that are insulated to prevent heat loss or heat absorption. This insulation is often made up of several materials, with calcium based material being the most dense. The insulating material is usually wrapped with an aluminum or stainless steel outer wrap. Verification of wall thickness of these pipes can be accomplished by removing the insulation and doing an ultrasound inspection or by taking x- rays at a tangent to the edge of the pipe through the insulation. Both of these processes are slow and expensive. The time required to obtain data is measured in hours per meter. The ultrasound method requires that the insulation be plugged after the inspection. The surface needs to be cleaned or the resulting data will not be accurate. The tangent x-ray only shows two thicknesses and requires that the area be roped off because of radiation safety.

Pascente, Joseph E.

1998-03-01

64

Effects of the flexibility of the arterial wall on the wall shear stresses and wall tension in Abdominal Aortic Aneurysms.  

NASA Astrophysics Data System (ADS)

As an abdominal aortic aneurysm develops, large changes occur in the composition and structure of the arterial wall, which result in its stiffening. So far, most studies, whether experimental or numerical, have been conducted assuming the walls to be rigid. A numerical simulation of the fluid structure interactions is performed in different models of aneurysms in order to analyze the effects that the wall compliance might have on the flow topology. Both symmetric and non-symmetric models of aneurysms are considered, all idealistic in shape. The wall mechanical properties are varied in order to simulate the progressive stiffening of the walls. The spatial and temporal distributions of wall tension are calculated for the different values of the wall elasticity and compared to the results for the rigid walls. In the case of rigid walls, the calculation of the wall shear stresses and pressure compare very well with experimental results.

Salsac, Anne-Virginie; Fernandez, Miguel; Chomaz, Jean-Marc

2005-11-01

65

Postoperative fistula of the abdominal wall after laparascopic cholecystectomy due to lost gallstones  

Microsoft Academic Search

Abdominal fistula caused by cholesterol gallstones, which remained in the abdominal wall after laparascopic cholecystectomy: a laparascopic cholecystectomy was performed in a 60-years-old man who was diagnosed as acute necrosing cholecystitis due to cholecystolithiasis. After removal of the gallbladder using an Endocath some gallstones remained in the excision channel of the abdominal wall. Therefore, a fistula developed in the excision

H. Weiler; A. Grandel

2002-01-01

66

Anterior Abdominal Wall Abscess Secondary to Subcutaneous Gallstones  

PubMed Central

Abdominal wall abscess secondary to spontaneous cholecystocutaneous gallstone fistulation is an uncommon presentation of a rare pathological process. Having been described relatively frequently in the 19th century, it is now much less common in the late 20th and early 21st century, probably due to earlier recognition of symptoms, better imaging and surgical treatment of biliary tract disease. Here we describe a report of a case with an unusual clinical presentation of the already rare pathological disease process of spontaneous cholecystocutaneous fistula.

Murphy, John A.; Vimalachandran, C. Dale; Howes, Nathan; Ghaneh, Paula

2008-01-01

67

In vivo evaluation of acellular human dermis for abdominal wall repair.  

PubMed

Limitations of synthetic biomaterials for abdominal wall repair have led investigators to seek naturally derived matrices, such as human acellular dermis, because of their excellent biocompatibility and their ability to naturally interface with host tissues with minimal tissue response. In this study, we investigated two different biomaterials derived from human dermis (FlexHD acellular dermis and FlexHD acellular dermis-thick) in a rabbit abdominal hernia repair model. One quarter of the abdominal wall was replaced with each biomaterial, and the animals were followed for up to 24 weeks. Rabbit hernias repaired with AlloDerm, a commercially available acellular dermal matrix, and sham operated animals served as controls. Retrieved samples of these implants were assessed grossly and histologically. Collagen production measurements and tension studies were performed. FlexHD acellular dermis, FlexHD acellular dermis-thick, and AlloDerm maintained their strength in the rabbit hernia repair model with no incidence of hernia formation or bowel adhesion. The exact size measurements at 24 weeks were 217.0 +/- 20.9% for FlexHD acellular dermis, 200.8 +/- 23.5% for FlexHD acellular dermis-thick, and 209.7 +/- 32.9% for AlloDerm. Macroscopic and microscopic evaluation showed excellent integration and tissue formation. All biomaterials studied harbored cells that produced new collagen fibers, and a six-fold increase in these fibers was observed at 24 weeks. This study shows that acellular biomaterials derived from human dermis are suitable for abdominal hernia repair. PMID:20014294

Eberli, Daniel; Rodriguez, Sergio; Atala, Anthony; Yoo, James J

2010-06-15

68

Evaluation of a new composite prosthesis for the repair of abdominal wall defects.  

PubMed

The degree of integration of biomaterials used in the repair of abdominal wall defects seems to depend upon the structure of the prosthesis. The present investigation evaluates the behaviour in terms of adhesion formation and integration of a new composite prosthesis that could be employed in this clinical application. Full-thickness abdominal wall defects (7 x 5 cm) were created in 16 anaesthetized New Zealand white rabbits and the prosthesis were placed in direct contact with the visceral peritoneum during the experiment. The defects were repaired with a composite prosthesis or pure polypropylene mesh to establish two study groups (n = 8 each). The composite device was constituted by a polypropylene mesh physically attached to a poly(ether)urethane-polydimethylsiloxane laminar sheet. Animals were sacrificed 7, 14, 21 and 30 days after implant and prosthesis/surrounding tissue specimens subjected to light and electron microscopy. Firm adhesions were detected in the polypropylene implants, while they were not present in the composite implants. The excellent behaviour of the composite prosthesis shown in this study warrants further investigation on its use for the repair of abdominal wall defects when a prosthetic device needs to be placed in contact with the intestinal loops. PMID:17554600

Losi, Paola; Munaò, Antonella; Spiller, Dario; Briganti, Enrica; Martinelli, Ilaria; Scoccianti, Marco; Soldani, Giorgio

2007-10-01

69

Biometric estimation of chest wall thickness of females  

SciTech Connect

Optimal use of whole-body counting data to estimate pulmonary deposition of many of the actinides is dependent upon accurate measurement of the thickness of the chest wall because of severe attenuation of low-energy x rays and photons associated with the decay of these radionuclides. An algorithm for estimation of female chest wall thicknesses, verified by real-time ultrasonic measurements, has been derived based on the correlation of measured chest wall thickness and other common biometric quantities. Use of this algorithm will reduce the error generally associated with estimation of internal actinide deposition previously resulting from assuming an average chest wall thickness for all female subjects.

Berger, C.D.; Lane, B.H.

1985-09-01

70

Traumatic anterior abdominal wall hernia: A report of three rare cases  

PubMed Central

Traumatic abdominal wall hernia is a rare condition that can follow any blunt trauma. Associated intra-abdominal injuries are infrequent. In this study, we are reporting three cases, diagnosed as abdominal wall hernia associated with herniation of bowel loops due to blunt trauma. In one case, injury of the herniated bowel was seen. In western medical literature, only few cases have been reported especially with intra-abdominal injuries.

Singal, Rikki; Dalal, Usha; Dalal, Ashwani Kumar; Attri, Ashok Kumar; Gupta, Raman; Gupta, Anupama; Naredi, Bikash; Kenwar, Deepesh Benjamin; Gupta, Samita

2011-01-01

71

Abdominoplasty and abdominal wall rehabilitation: a comprehensive approach.  

PubMed

Standard abdominoplasty techniques involve a low horizontal or W skin excision, muscle plication, and umbilical transposition. Newer techniques include suction-assisted lipectomy, the use of high lateral tension with fascial suspension, and external oblique muscle advancement. The author has modified these traditional procedures and added new techniques to improve the aesthetic and functional results of the abdominoplasty procedure. This modification provides a comprehensive approach to abdominal wall aesthetic improvement and rehabilitation. The comprehensive approach described includes four components: the "U-M dermolipectomy," "V umbilicoplasty," the rectus abdominis "myofascial release," and suction-assisted lipectomy. The patient is marked while standing for areas of suction lipectomy and undermining. The lower incision is designed as an open U with the lateral limbs placed inside the bikini line. The upper incision is a lazy M with the higher peaks located at the level of the flanks. Subcutaneous hydration is achieved to perform suction along the flanks, waistline, and iliac areas. Gentle suction of the flaps is also performed. The umbilicus is cored out in a heart shape. The flaps within the U-M marks are excised, and the undermining is performed to the xiphoid and costal margins. The rectus diastasis is marked, and the anterior rectus fascia is incised at the junction of the medial third with the central third of the width of the rectus sheath. Horizontal figure-eight plication sutures by using the lateral fascial edge enable easier infolding of the central tissue. The new recipient of the umbilicus is made by an incision in a V shape on the abdominal flap. The umbilicus is telescoped, and the triangular flap of the abdomen is sutured to the triangular defect of the umbilicus. Skin flap fixation to the umbilicus relieves tension in the lower portion of the flap. The upper skin flap, which is cut in an M manner, provides lateral tension and matches the length of the lower flap. A standard fascial suspension is used and closure is performed in layers. The techniques described here are intertwined procedures. Each facilitates the accomplishment of the other procedure, and they complement each other. They all attain the 12 objectives of the abdominoplasty described. These combined techniques have been used in 104 patients in a period of 11 years. Complications were minimal and easily manageable, except for one patient who required excision of a pseudobursa and retightening of the lower quadrants of the abdominal wall musculature to correct extreme lordosis. A comprehensive approach for the treatment of complex abdominal wall aesthetic and functional defects is presented. These require thoughtful integration of the four components mentioned. This approach has allowed predictable, reproducible, and aesthetically pleasing results. PMID:10627012

Ramirez, O M

2000-01-01

72

[Gasless laparoscopic cholecystectomy using retractor of the abdominal wall].  

PubMed

The Authors present a new gasless laparoscopic cholecystectomy method using an abdominal wall elevator with subcutaneous traction ("laparotenser"). Fifty patients between May 1994 and March 1995 were operated by videolaparoscopy using this new gasless method. Twenty of them were operated with Nagai's method while the laparotenser was used in the remaining thirty. The results obtained are similar to those using pneumoperitoneum. It has been observed a global reduction of costs, less postoperative pain, no influence in cardiovascular and metabolic indexes. No complications were reported during the postoperative period but two cases of conversion to laparotomy not related to the method used were needed. Laparoscopic cholecystectomy without pneumoperitoneum using the subcutaneous elevator of the abdominal wall ("laparotenser") has demonstrated that it's possible to operate in a working space similar to that created by the pneumoperitoneum. After an initial period of distrust towards the laparoscopic methods without pneumoperitoneum it has been accepted that gasless methods multiply the indications to minimally invasive surgery in patients with cardiorespiratory problems considered no ideal candidates to laparoscopic cholecystectomy with pneumoperitoneum. PMID:8679422

D'Urbano, C; Fuertes Guiro, F; Sampietro, R

1996-03-01

73

An abdominal wall simulator for testing suprapubic urinary catheters.  

PubMed

Urinary catheters (drainage tubes) are in widespread use. The most common type of long-term catheter is the Foley, which is made from natural or synthetic rubber. Foley catheters are passed into the bladder via the urethra or the suprapubic puncture channel (through the abdominal wall). A simulator for the abdominal wall has been developed to simulate aspects of the interaction between it and a suprapubic catheter. The simulator is based on a slab of ultrasoft elastomer with tensionable reinforcing polyamide filaments. The behaviour of the simulator has been compared with data published. A soft membrane (contact pressure) transducer (SMT) was used and novel instrumented 'tongs' for lateral indentation of the puncture track giving indentation stiffness. Slab materials were used with shear moduli of 0.1 and 0.021 MPa. Two filament-tensioning methods were used: by clamping to a winding mechanism and by weights. The combination of the softer slab material and tensioning by weights gave good conformity to physiological data; other combinations did not. PMID:11556670

Coveney, V A; Gröver, D

2001-08-01

74

[Diagnostic difficulty of abdominal wall endometrioma: clinical case and literature review].  

PubMed

Abdominal wall endometrioma is a rare clinical condition with which the general surgeon is faced and usually presents a diagnostic challenge due to the similar signs and symptoms that this illness shares with other tumors of the abdominal wall. A clinical case which exemplifies this diagnostic challenge is presented, and a review is made about the physiopathology, diagnosis and treatment of abdominal wall endometriomas, emphasizing on the different diagnoses with which it can be confused. PMID:18798406

Martínez, Denzil Garteiz; Romano, Rafael Carbo; Sánchez, Alejandro Weber; Horcasitas, Lourdes Molinar

2008-02-01

75

Elasticity of the anterior abdominal wall and impact for reparation of incisional hernias using mesh implants  

Microsoft Academic Search

Summary.   Mesh implantation to repair incisional hernia involves extensive disturbance of the integrity of the abdominal wall. To define\\u000a the physiological requirements, we measured the elasticity of the abdominal wall of 14 anatomic samples. The complete abdominal\\u000a wall was excised and stretched at a strain of 0–24 N in horizontal, vertical and oblique (upper and lower abdomen) directions.\\u000a The resulting mean

K. Junge; U. Klinge; A. Prescher; P. Giboni; M. Niewiera; V. Schumpelick

2001-01-01

76

Reconstruction of Abdominal Wall Musculofascial Defects with Small Intestinal Submucosa Scaffolds Seeded with Tenocytes in Rats  

PubMed Central

The repair of abdominal wall defects following surgery remains a difficult challenge. Although multiple methods have been described to restore the integrity of the abdominal wall, there is no clear consensus on the ideal material for reconstruction. This study explored the feasibility of in vivo reconstruction of a rat model of an abdominal wall defect with a composite scaffold of tenocytes and porcine small intestinal submucosa (SIS). In the current study, we created a 2×1.5?cm abdominal wall defect in the anterolateral abdominal wall of Sprague-Dawley rats, which were assigned into three groups: the cell-SIS construct group, the cell-free SIS scaffold group, and the abdominal wall defect group. Tenocytes were obtained from the tendons of rat limbs. After isolation and expansion, cells (2×107/mL) were seeded onto the three-layer SIS scaffolds and cultured in vitro for 5 days. Cell-SIS constructs or cell-free constructs were implanted to repair the abdominal wall defects. The results showed that the tenocytes could grow on the SIS scaffold and secreted corresponding matrices. In addition, both scaffolds could repair the abdominal wall defects with no hernia recurrence. In comparison to the cell-free SIS scaffold, the composite scaffold exhibited increased vascular regeneration and mechanical strength. Furthermore, following increased time in vivo, the mechanical strength of the composite scaffold became stronger. The results indicate that the composite scaffold can provide increased mechanical strength that may be suitable for repairing abdominal wall defects.

Song, Zhicheng; Peng, Zhiyou; Liu, Zhengni; Yang, Jianjun; Tang, Rui

2013-01-01

77

Evaluation of Tube Wall Thickness of Feed Water Heater  

Microsoft Academic Search

With regard to the high pressure (HP) feed water heater of thermal power plant at Tokyo Electric Power Company (TEPCO) sites, inspection of feed water (FW) tubes wall thickness are conducted whenever required such that frequent tube leak occurs. As a standard inspection methodology, FW heater is disassembled during planned outage, tube wall thickness is measured by the ultrasonic pulse

Takahisa Uchikura; Koichi Morisaki; Seiichi Hamada

2008-01-01

78

Thickness of Rectus Abdominis Muscle and Abdominal Subcutaneous Fat Tissue in Adult Women: Correlation with Age, Pregnancy, Laparotomy, and Body Mass Index  

PubMed Central

Background Rectus abdominis muscle and abdominal subcutaneous fat tissue are useful for reconstruction of the chest wall, and abdominal, vaginal, and perianal defects. Thus, preoperative evaluation of rectus abdominis muscle and abdominal subcutaneous fat tissue is important. This is a retrospective study that measured the thickness of rectus abdominis muscle and abdominal subcutaneous fat tissue using computed tomography (CT) and analyzed the correlation with the patients' age, gestational history, history of laparotomy, and body mass index (BMI). Methods A total of 545 adult women were studied. Rectus abdominis muscle and abdominal subcutaneous fat thicknesses were measured with abdominopelvic CT. The results were analyzed to determine if the thickness of the rectus abdominis muscle or subcutaneous fat tissue was significantly correlated with age, number of pregnancies, history of laparotomy, and BMI. Results Rectus abdominis muscle thicknesses were 9.58 mm (right) and 9.73 mm (left) at the xiphoid level and 10.26 mm (right) and 10.26 mm (left) at the umbilicus level. Subcutaneous fat thicknesses were 24.31 mm (right) and 23.39 mm (left). Rectus abdominismuscle thickness decreased with age and pregnancy. History of laparotomy had a significant negative correlation with rectus abdominis muscle thickness at the xiphoid level. Abdominal subcutaneous fat thickness had no correlation with age, number of pregnancies, or history of laparotomy. Conclusions Age, gestational history, and history of laparotomy influenced rectus abdominis muscle thickness but did not influence abdominal subcutaneous fat thickness. These results are clinically valuable for planning a rectus abdominis muscle flap and safe elevation of muscle flap.

Kim, Jungmin; Lim, Hyoseob; Lee, Se Il

2012-01-01

79

Fetal abdominal wall repair with a collagen biomatrix in an experimental sheep model for gastroschisis.  

PubMed

We evaluated the regeneration of the abdominal wall using a dual-layer collagen biomatrix, and the protective effect on the bowel of fetal abdominal wall repair in a fetal sheep model for gastroschisis. In 14 fetal lambs, the abdominal wall was opened at 79 days' gestation, creating a gastroschisis. In group 1, the gastroschisis was left uncovered. In group 2, the bowel was repositioned, and the defect was closed by suturing a collagen biomatrix into the abdominal wall. A cesarean section was performed at 140 days' gestation, and macroscopic and histological evaluation was performed. In the five lambs with a gastroschisis, the eviscerated part of the bowel was coalescent, showed extensive adhesions, and was covered by fibrous peel. In group 2, the abdominal wall had closed, with a firm connection to the native abdominal wall. The biomatrix was largely degraded and replaced by connective tissue with collagen and fibroblasts, neovascularisation, and scattered muscle cells. Minor or no adhesions of the bowel and no peel formation were observed. Abdominal wall tissue replacement using a collagen biomatrix was feasible in fetal lambs, resulting in a closed abdominal wall at birth. Immediate closure of the gastroschisis strongly diminished or prevented bowel adhesions and peel formation. PMID:18636946

Roelofs, Luc A J; Eggink, Alex J; Hulsbergen-van de Kaa, Christina A; van den Berg, Paul P; van Kuppevelt, Toin H; van Moerkerk, Herman T B; Crevels, A Jane; Lotgering, Fred K; Feitz, Wout F J; Wijnen, Rene M H

2008-12-01

80

Influence of Temporary Abdominal Wall Repair on the Intestinal Integrity: An Experimental Study in the Rat  

Microsoft Academic Search

Background and Aims: The aim of this study was to analyze intestinal integrity after temporary abdominal wall repair with absorbable mesh. Methods: Rats underwent abdominal wall repair with absorbable mesh or sham operation. Myeloperoxidase-positive cells in the intestinal muscularis were histochemically quantified. Intestinal transit was visualized 48 h after surgery. Local and systemic inflammatory response was measured with TNF-? and

M. Overhaus; N. Schaefer; A. Hirner; J. C. Kalff; R. H. Tolba

2008-01-01

81

Measuring and modeling patient-specific distributions of material properties in abdominal aortic aneurysm wall.  

PubMed

Both the clinically established diameter criterion and novel approaches of computational finite element (FE) analyses for rupture risk stratification of abdominal aortic aneurysms (AAA) are based on assumptions of population-averaged, uniform material properties for the AAA wall. The presence of inter-patient and intra-patient variations in material properties is known, but has so far not been addressed sufficiently. In order to enable the preoperative estimation of patient-specific AAA wall properties in the future, we investigated the relationship between non-invasively assessable clinical parameters and experimentally measured AAA wall properties. We harvested n = 163 AAA wall specimens (n = 50 patients) during open surgery and recorded the exact excision sites. Specimens were tested for their thickness, elastic properties, and failure loads using uniaxial tensile tests. In addition, 43 non-invasively assessable patient-specific or specimen-specific parameters were obtained from recordings made during surgery and patient charts. Experimental results were correlated with the non-invasively assessable parameters and simple regression models were created to mathematically describe the relationships. Wall thickness was most significantly correlated with the metabolic activity at the excision site assessed by PET/CT (? = 0.499, P = 4 × 10(-7)) and to thrombocyte counts from laboratory blood analyses (? = 0.445, P = 3 × 10(-9)). Wall thickness was increased in patients suffering from diabetes mellitus, while it was significantly thinner in patients suffering from chronic kidney disease (CKD). Elastic AAA wall properties had significant correlations with the metabolic activity at the excision site (PET/CT), with existent calcifications, and with the diameter of the non-dilated aorta proximal to the AAA. Failure properties (wall strength and failure tension) had correlations with the patient's medical history and with results from laboratory blood analyses. Interestingly, AAA wall failure tension was significantly reduced for patients with CKD and elevated blood levels of potassium and urea, respectively, both of which are associated with kidney disease. This study is a first step to a future preoperative estimation of AAA wall properties. Results can be conveyed to both the diameter criterion and FE analyses to refine rupture risk prediction. The fact that AAA wall from patients suffering from CKD featured reduced failure tension implies an increased AAA rupture risk for this patient group at comparably smaller AAA diameters. PMID:22955570

Reeps, C; Maier, A; Pelisek, J; Härtl, F; Grabher-Meier, V; Wall, W A; Essler, M; Eckstein, H-H; Gee, M W

2013-08-01

82

Granular cell tumor of the abdominal wall: case report and review of the literature.  

PubMed

Granular cell tumors (GCT's) are uncommon soft tissue neoplasms most likely of neural or neuroectodermal origin. They can be found in virtually any body site, but they are rarely located in the abdominal wall. We report the case of a patient with a history of breast cancer presenting with a slow-growing, firm and painless nodule in the abdominal wall. After ruling out metastatic origin of the mass by CT scan and MRI, an incisional biopsy was performed. Anatomopathologic findings were congruent with a benign granular cell tumor of the abdominal wall. En-bloc surgical resection with reconstruction of the abdominal wall defect using a prosthetic mesh was performed. Preoperative histopathologic diagnosis of an abdominal wall tumor is important. Broad surgical excision to obtain negative margins should be the therapeutic goal in all cases of GCT as positive margins are highly correlated with recurrence of the lesion. PMID:24294803

Toelen, C; Goovaerts, G; Huyghe, M

2013-01-01

83

Wall stress reduction in abdominal aortic aneurysms as a result of polymeric endoaortic paving.  

PubMed

Polymeric endoaortic paving (PEAP) may improve endovascular repair of abdominal aortic aneurysms (AAA) since it has the potential to treat patients with complex AAA geometries while reducing the incidence of migration and endoleak. Polycaprolactone (PCL)/polyurethane (PU) blends are proposed as PEAP materials due to their range of mechanical properties, thermoformability, and resistance to biodegradation. In this study, the reduction in AAA wall stress that can be achieved using PEAP was estimated and compared to that resulting from stent-grafts. This was accomplished by mechanically modeling the anisotropic response of PCL/PU blends and implementing these results into finite element model (FEM) simulations. We found that at the maximum diameter of the AAA, the 50/50 and 10/90 PCL/PU blends reduced wall stress by 99 and 98%, respectively, while a stent-graft reduced wall stress by 99%. Our results also show that wall stress reduction increases with increasing PEAP thickness and PCL content in the blend ratio. These results indicate that PEAP can reduce AAA wall stress as effectively as a stent-graft. As such, we propose that PEAP may provide an improved treatment alternative for AAA, since many of the limitations of stent-grafts have the potential to be solved using this approach. PMID:21350892

Ashton, John H; Ayyalasomayajula, Avinash; Simon, Bruce R; Vande Geest, Jonathan P

2011-06-01

84

Cross-Barrel Temperature Difference Due to Wall Thickness Variation.  

National Technical Information Service (NTIS)

Advances in manufacturing techniques have reduced, but not eliminated, cross-barrel wall thickness variation in the production of gun barrels. Structurally, these small variations will not appreciably diminish the strength of the barrel, and are, therefor...

N. Gerber M. L. Bundy

1993-01-01

85

Analysis of Short Cylindrical Shells of Variable Wall Thickness.  

National Technical Information Service (NTIS)

Transfer matrices are developed relating stress resultants, moments, displacements, and rotations at the two ends of a short cylindrical shell with variable wall thickness. The matrix elements are derived through Taylor's expansions for the variables (inc...

W. E. Jahsman O. Hoffman

1965-01-01

86

Myocardium wall thickness transducer and measuring method  

NASA Technical Reports Server (NTRS)

A miniature transducer for measuring changes of thickness of the myocardium is described. The device is easily implantable without traumatizing the subject, without affecting the normal muscle behavior, and is removable and implantable at a different muscle location. Operating features of the device are described.

Feldstein, C.; Lewis, G. W.; Silver, R. H.; Culler, V. H. (inventors)

1976-01-01

87

Evaluation of Tube Wall Thickness of Feed Water Heater  

NASA Astrophysics Data System (ADS)

With regard to the high pressure (HP) feed water heater of thermal power plant at Tokyo Electric Power Company (TEPCO) sites, inspection of feed water (FW) tubes wall thickness are conducted whenever required such that frequent tube leak occurs. As a standard inspection methodology, FW heater is disassembled during planned outage, tube wall thickness is measured by the ultrasonic pulse techique (UT), then plugs are installed at the both ends of FW tube if its measured wall thickness is found below calculated threshold. However, the root causes of wall thinning of FW tube are various such as erosion and corrosion, based on wall thinning condition, the above threshold is not applied but utilizing the other technically well-grounded evaluation method is sometimes more rational. Therefore, TEPCO classified wall-thinning condition based on inspection data and established technically well-grounded and rational evaluation methodologies of FW tube wall thickness to suite each wall thinning condition. Moreover, with recent improvement of inspection technique, technology enabled faster, larger amount, and more accurate data acquisition, TEPCO has developed the systematized evaluation methodology that can transact data acquisition and evaluation simultaneously. This article introduces the logic of evaluation methods and examined algorithms to make them systematized.

Uchikura, Takahisa; Morisaki, Koichi; Hamada, Seiichi

88

Influence of wall thickness on the stability of the resistive wall mode in tokamak plasmas  

SciTech Connect

The influence of finite wall thickness on the stability of the resistive wall mode (RWM) in a tokamak is determined using a simple cylindrical plasma model in which the dissipation required to stabilize the mode is provided by neoclassical parallel ion viscosity. For present-day tokamaks, which possess relatively thin walls, finite wall thickness effects are found to have relatively little influence on the RWM stability boundaries, which are almost the same as those calculated in the thin-wall limit. On the other hand, for next-step devices, which are likely to possess much thicker walls than present-day tokamaks, finite wall thickness effects are found to significantly impede the ability of plasma rotation to stabilize the RWM all the way to the perfect-wall stability limit.

Fitzpatrick, Richard [Department of Physics, Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

2013-01-15

89

Reconstruction of abdominal wall musculofascial defects with small intestinal submucosa scaffolds seeded with tenocytes in rats.  

PubMed

The repair of abdominal wall defects following surgery remains a difficult challenge. Although multiple methods have been described to restore the integrity of the abdominal wall, there is no clear consensus on the ideal material for reconstruction. This study explored the feasibility of in vivo reconstruction of a rat model of an abdominal wall defect with a composite scaffold of tenocytes and porcine small intestinal submucosa (SIS). In the current study, we created a 2×1.5?cm abdominal wall defect in the anterolateral abdominal wall of Sprague-Dawley rats, which were assigned into three groups: the cell-SIS construct group, the cell-free SIS scaffold group, and the abdominal wall defect group. Tenocytes were obtained from the tendons of rat limbs. After isolation and expansion, cells (2×10(7)/mL) were seeded onto the three-layer SIS scaffolds and cultured in vitro for 5 days. Cell-SIS constructs or cell-free constructs were implanted to repair the abdominal wall defects. The results showed that the tenocytes could grow on the SIS scaffold and secreted corresponding matrices. In addition, both scaffolds could repair the abdominal wall defects with no hernia recurrence. In comparison to the cell-free SIS scaffold, the composite scaffold exhibited increased vascular regeneration and mechanical strength. Furthermore, following increased time in vivo, the mechanical strength of the composite scaffold became stronger. The results indicate that the composite scaffold can provide increased mechanical strength that may be suitable for repairing abdominal wall defects. PMID:23402600

Song, Zhicheng; Peng, Zhiyou; Liu, Zhengni; Yang, Jianjun; Tang, Rui; Gu, Yan

2013-07-01

90

49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.  

Code of Federal Regulations, 2013 CFR

... false Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation...109 Nominal wall thickness (t ) for steel pipe. (a) If the nominal wall thickness for steel pipe is not known, it is determined...

2013-10-01

91

Bladder wall thickness mapping for magnetic resonance cystography  

NASA Astrophysics Data System (ADS)

Clinical studies have shown evidence that the bladder wall thickness is an effective biomarker for bladder abnormalities. Clinical optical cystoscopy, the current gold standard, cannot show the wall thickness. The use of ultrasound by experts may generate some local thickness information, but the information is limited in field-of-view and is user dependent. Recent advances in magnetic resonance (MR) imaging technologies lead MR-based virtual cystoscopy or MR cystography toward a potential alternative to map the wall thickness for the entire bladder. From a high-resolution structural MR volumetric image of the abdomen, a reasonable segmentation of the inner and outer borders of the bladder wall can be achievable. Starting from here, this paper reviews the limitation of a previous distance field-based approach of measuring the thickness between the two borders and then provides a solution to overcome the limitation by an electric field-based strategy. In addition, this paper further investigates a surface-fitting strategy to minimize the discretization errors on the voxel-like borders and facilitate the thickness mapping on the three-dimensional patient-specific bladder model. The presented thickness calculation and mapping were tested on both phantom and human subject datasets. The results are preliminary but very promising with a noticeable improvement over the previous distance field-based approach.

Zhao, Yang; Liang, Zhengrong; Zhu, Hongbin; Han, Hao; Duan, Chaijie; Yan, Zengmin; Lu, Hongbing; Gu, Xianfeng

2013-08-01

92

Bladder Wall Thickness Mapping for Magnetic Resonance Cystography  

PubMed Central

Clinical studies have shown the evidence that the bladder wall thickness is an effective biomarker for bladder abnormalities. The clinical optical cystoscopy, the current gold standard, cannot show the wall thickness. The use of ultrasound by experts may generate some local thickness information, but the information is limited in field-of-view and is user dependent. Recent advances in magnetic resonance (MR) imaging technologies lead MR-based virtual cystoscopy or MR cystography toward a potential alternative to map the wall thickness for the entire bladder. From a high resolution structural MR volumetric image of the abdomen, a reasonable segmentation of the inner and outer borders of the bladder wall can be achievable. Starting from here, this paper reviews the limitation of a previous distance field-based approach of measuring the thickness between the two borders and then provides a solution to overcome the limitation by an electric field-based strategy. In addition, this paper further investigates a surface fitting strategy to minimize the discretization errors on the voxel-like borders and facilitate the thickness mapping on the three-dimensional patient-specific bladder model. The presented thickness calculation and mapping were tested on both phantom and human subject datasets. The results are preliminary but very promising with a noticeable improvement over the previous distance field-based approach.

Zhao, Yang; Liang, Zhengrong; Zhu, Hongbin; Han, Hao; Duan, Chaijie; Yan, Zengmin; Lu, Hongbing; Gu, Xianfeng

2013-01-01

93

Abdominal wall and stomach perforation following accidental electrocution with high tension wire: a unique case.  

PubMed

The usual form of direct gastrointestinal injury following high-tension electric injury is widespread necrosis of the colon or the small intestine. It usually occurs in combination with extensive electric burns of the overlying abdominal wall. We report a case of immediate post-electrocution abdominal wall and stomach perforation following high tension electric injury. The total absence of coagulation necrosis of the stomach or other portions of the gastrointestinal tract and the absence of burns of the abdominal wall were other unique features of the case reported. The patient was successfully treated. PMID:8505515

Kumar, S; Thomas, S; Lehri, S

1993-01-01

94

The use of Surgisis for abdominal wall reconstruction in the separation of omphalopagus conjoined twins.  

PubMed

Abdominal wall reconstruction in omphalopagus twins poses a difficult reconstructive challenge, as separation often results in a large abdominal wall defect. A number of options are available for closure, including tissue flaps, expanders and patches made of foreign material. Surgisis is a new biodegradable small intestine scaffolding substrate that permits tissue in-growth and results in a permanent durable scar. We describe its use in abdominal wall reconstruction after separation of a set of conjoined twins. A set of omphalopagus conjoined twins shared liver and abdominal wall. After separation at 6 months of age, Twin A's abdomen could be closed primarily, but Twin B could not. A 4-ply Surgisis mesh was used in the upper abdominal closure, and a skin flap was created, to completely cover the patch. Both twins survived the operation. A small portion of the skin flap over the Surgisis broke down, healing by secondary intention. In follow up of over 18 months post procedure, there have been no wound infections and the abdominal wall is intact with no evidence of a hernia. Surgisis can be successfully used for the reconstruction of complex abdominal wall defects in the pediatric patient, including reconstruction after separation of conjoined twins. PMID:17437118

Dasgupta, Roshni; Wales, Paul W; Zuker, Ronald M; Fisher, David M; Langer, Jacob C

2007-09-01

95

Evolution of the wall shear stresses during the progressive enlargement of symmetric abdominal aortic aneurysms  

Microsoft Academic Search

The changes in the evolution of the spatial and temporal distribution of the wall shear stresses (WSS) and gradients of wall shear stresses (GWSS) at different stages of the enlargement of an abdominal aortic aneurysm (AAA) are important in understanding the aetiology and progression of this vascular disease since they affect the wall structural integrity, primarily via the changes induced

S. R. S PARKS; J.-M. C HOMAZ; J. C. L ASHERAS

96

Architectural and morphological assessment of rat abdominal wall muscles: comparison for use as a human model  

PubMed Central

The abdominal wall is a composite of muscles that are important for the mechanical stability of the spine and pelvis. Tremendous clinical attention is given to these muscles, yet little is known about how they function in isolation or how they interact with one another. Given the morphological, vascular, and innervation complexities associated with these muscles and their proximity to the internal organs, an appropriate animal model is important for understanding their physiological and mechanical significance during function. To determine the extent to which the rat abdominal wall resembles that of human, 10 adult male Sprague-Dawley rats were killed and formalin-fixed for architectural and morphological analyses of the four abdominal wall muscles (rectus abdominis, external oblique, internal oblique, and transversus abdominis). Physiological cross-sectional areas and optimal fascicle lengths demonstrated a pattern that was similar to human abdominal wall muscles. In addition, sarcomere lengths measured in the neutral spine posture were similar to human in their relation to optimal sarcomere length. These data indicate that the force-generating and length change capabilities of these muscles, relative to one another, are similar in rat and human. Finally, the fiber lines of action of each abdominal muscle were similar to human over most of the abdominal wall. The main exception was in the lower abdominal region (inferior to the pelvic crest), where the external oblique becomes aponeurotic in human but continues as muscle fibers into its pelvic insertion in the rat. We conclude that, based on the morphology and architecture of the abdominal wall muscles, the adult male Sprague-Dawley rat is a good candidate for a model representation of human, particularly in the middle and upper abdominal wall regions.

Brown, Stephen H M; Banuelos, Karina; Ward, Samuel R; Lieber, Richard L

2010-01-01

97

Synovial sarcoma of the abdominal wall: a case report and study of its fine structure.  

PubMed

A case of synovial sarcoma in the abdominal wall of a 50-year-old Iraq female is reported. The ultrastructure of the tumor has been studied. Eight other cases of synovial sarcoma in the abdominal wall which reported in the English literature up to 1978 have been reviewed. Synovial sarcomas in the abdominal wall tend to occur with a much greater frequency in females in contrast to such tumors in the extremities or the neck which tend to occur with a much greater frequency in males. No ultrastructure studies of abdominal wall synovial sarcomas could be found in the English literature. Ultrastructure characteristics of this tumor were similar to those arising in the usual sites and in the neck. However, the present study has indicated that the light and dark cells reported by earlier workers are not solely limited to the epitheloid areas but are also present in the spindle cell zones. PMID:6275210

Al-Dewachi, H S; Sangal, B C; Zakaria, M A

1981-01-01

98

Case of a sigmoid colon cancer with metachronous metastases to the mesorectum and the abdominal wall  

Microsoft Academic Search

BACKROUND: Sigmoid colon cancer metachronous metastases commonly occur in the liver and lungs with sporadic reports also to the spleen, stomach, thyroid gland, abdominal wall and upper urinary tract. This is a rare case of metachronous metastases invading the mesorectum and the abdominal wall. CASE PRESENTATION: A 72-year-old female underwent sigmoidectomy for stage I (T2N0 M0) sigmoid colon cancer in

John Kalaitzis; George Filippou; Adamantia Zizi-Sermpetzoglou; Athanasios Marinis; Andreas Hadjimarcou; Nikolaos Paschalidis; Spyros Rizos

2010-01-01

99

An unusual case of abdominal wall bleeding after renal allograft biopsy  

PubMed Central

We report an unusual case of a enlarging anterior abdominal wall hematoma after percutaneous biopsy of a renal allograft. Angiography-directed embolization of the vessels filling the pseudoaneurysm was done and followed up with surgical exploration of the hematoma. In order to avoid this complication, Color Doppler evaluation of the overlying abdominal wall is suggested to look for significant vessels before the biopsy procedure.

Koshy, C. G.; Chacko, B. R.; Babu, S.; Basu, G.; Selvaraj, D.; John, G. T.

2011-01-01

100

Repair and regeneration of the abdominal wall musculofascial defect using silk fibroin-chitosan blend.  

PubMed

Reconstructive surgery with synthetic or biological materials is commonly performed to repair abdominal wall musculofascial defects that result from ventral hernias. A study was conducted to investigate the feasibility of using silk fibroin and chitosan blend (SFCS) scaffolds for ventral hernia repair in guinea pigs. We compared SFCS with biodegradable human acellular dermal matrix (HADM) and nonbiodegradable polypropylene mesh by implanting each to repair an incisionally created ventral hernia in the abdominal wall using an inlay technique. At 4 weeks, both HADM and SFCS underwent remodeling by host tissue, but polypropylene mesh resulted in extensive bowel adhesions and scarring. Abdominal wall repairs with SFCS showed tissue remodeling in all 3 dimensions, with seamless integration at the interface with adjacent native tissue. The SFCS repair sites remained intact, and their mechanical strength was similar to that of the native abdominal wall despite greater degradation and remodeling of SFCS than of HADM. The deposition of new extracellular matrix consisting of collagen and ground substance, uniform vascularization, and cellular infiltration in SFCS repair sites contributed to the increase in mechanical strength of the regenerated tissue. Thus, SFCS is a potentially useful material for clinical abdominal wall reconstruction, since it becomes remodeled and integrated into the surrounding abdominal wall and maintains adequate tensile strength. PMID:17518675

Gobin, Andrea S; Butler, Charles E; Mathur, Anshu B

2006-12-01

101

Strain behavior of pressurized cracked thick-walled cylinders  

Microsoft Academic Search

External circumferential strains were measured on large thick-wall pressure vessels containing internal fatigue cracks, using\\u000a bonded strain gages. When strains measured over the cracks become compressive they predict impending failure. Normalization\\u000a by the Lam strain relates them to the fraction of fatigue life consumed and provides estimates of longevity.

J. F. Throop; R. R. Fujczak

1982-01-01

102

Excision of a large abdominal wall lipoma improved bowel passage in a Proteus syndrome patient  

PubMed Central

Proteus syndrome is an extremely rare congenital disorder that produces multifocal overgrowth of tissue. This report presents a surgical case of a large lipoma in the abdominal wall of a patient with Proteus syndrome. She was diagnosed with Proteus syndrome based on certain diagnostic criteria. The neoplasm increased in size gradually, producing hemihypertrophy of her left lower extremity and trunk, and spread to her retroperitoneum and her left abdominal wall. She experienced gradually progressive constipation, nausea, vomiting, and abdominal pain. Computed tomography (CT) of the abdomen demonstrated a large mass in the subcutaneous adipose tissue of the left lower abdominal wall which measured 12 cm × 8 cm x 6 cm in diameter and encased the left colon. This mass in the abdominal wall was excised. The weight of the excised mass was 1550 g. The histopathological diagnosis of this mass was lipoma. After surgery, the encasement of the left colon was improved, and the patient was able to move her bowels twice per day. The excision of the large lipoma in the abdominal wall contributed to the improved bowel passage in this patient with Proteus syndrome.

Nakayama, Yoshifumi; Kusuda, Shinichi; Nagata, Naoki; Yamaguchi, Koji

2009-01-01

103

Intra-abdominal pressure and abdominal wall muscular function: spinal unloading mechanism  

PubMed Central

BACKGROUND The roles of antagonistic activation of abdominal muscles and of intra-abdominal pressurization remain enigmatic, but are thought to be associated with both spinal unloading and spinal stabilization in activities such as lifting. Biomechanical analyses are needed to understand the function of intra-abdominal pressurization because of the anatomical and physiological complexity, but prior analyses have been over-simplified. METHODS To test whether increased intra-abdominal pressure was associated with reduced spinal compression forces for efforts that generated moments about each of the principal axis directions, a previously published biomechanical model of the spine and its musculature was modified by the addition of anatomically realistic three-layers of curved abdominal musculature connected by fascia to the spine. Published values of muscle cross-sectional areas and the active and passive stiffness properties were assigned. The muscle activations were calculated assuming minimized muscle stress and stretch for the model loaded with flexion, extension, lateral bending and axial rotation moments of up to 60 Nm, along with intra-abdominal pressurization of 5 or 10 kPa (37.5 or 75 mmHg) and partial bodyweight (340 N). FINDINGS The analysis predicted a reduction in spinal compressive force with increase in intra-abdominal pressurization from 5 to 10 kPa. This reduction at 60 Nm external effort was 21% for extension effort, 18% for flexion effort, 29% for lateral bending and 31% for axial rotation. INTERPRETATION This analysis predicts that intra-abdominal pressure produces spinal unloading, and shows likely muscle activation patterns that achieve this.

Stokes, Ian A.F.; Gardner-Morse, Mack G.; Henry, Sharon M.

2010-01-01

104

The effect of abdominal wall plication on intra-abdominal pressure and lower extremity venous flow: a case report  

PubMed Central

SUMMARY Abdominal wall plication is known to cause increased intra-abdominal pressure (IAP). Whether plication-associated increased IAP causes lower extremity venous stasis, a recognized risk factor for DVT, remains unknown. A 55 year old woman had a unilateral pedicled TRAM procedure for mastectomy reconstruction. Prior to plication, duplex ultrasound measured proximal femoral vein (PFV) cross-sectional diameter and volume-flow. PFV measurements were repeated immediately after plication and on post-operative days (POD) 1, 2, and 4. Bladder pressure was measured at similar timepoints. PFV volume-flow decreased from 0.22 L/min to 0.16 L/min (73% of baseline) immediately post-plication and reached a nadir of 0.08 L/min (36% of baseline) on POD 2. Bladder pressure increased from 13mm Hg to 19mm Hg after plication, and peaked at 31mmHg after intra-operative trunk flexion to 30°. Thus, abdominal wall placation was associated with increased intra-abdominal pressure and ultrasound-documented lower extremity venous stasis that persisted for 48 hours after surgery.

Pannucci, Christopher J.; Alderman, Amy K.; Brown, Sandra L.; Wakefield, Thomas W.; Wilkins, Edwin G.

2011-01-01

105

Association of intraluminal thrombus in abdominal aortic aneurysm with local hypoxia and wall weakening  

Microsoft Academic Search

Purpose: Our previous computer models suggested that intraluminal thrombus (ILT) within an abdominal aortic aneurysm (AAA) attenuates oxygen diffusion to the AAA wall, possibly causing localized hypoxia and contributing to wall weakening. The purpose of this work was to investigate this possibility. Methods: In one arm of this study, patients with AAA were placed in one of two groups: (1)

David A. Vorp; Paul C. Lee; David H. J. Wang; Michel S. Makaroun; Edwin M. Nemoto; Satoshi Ogawa; Marshall W. Webster

2001-01-01

106

Tissue engineering approach to repair abdominal wall defects using cell-seeded bovine tunica vaginalis in a rabbit model.  

PubMed

The aim of this study was to engineer skeletal muscle tissue for repair abdominal wall defects. Myoblast were seeded onto the scaffolds and cultivated in vitro for 5 days. Full thickness abdominal wall defects (3 x 4 cm) were created in 18 male New Zealand white rabbits and randomly divided into two equal groups. The defects of the first group were repaired with myoblast-seeded-bovine tunica vaginalis whereas the second group repaired with non-seeded-bovine tunica vaginalis and function as a control. Three animals were sacrificed at 7th, 14th, and 30th days of post-implantation from each group and the explanted specimens were subjected to macroscopic and microscopic analysis. In every case, seeded scaffolds have better deposition of newly formed collagen with neo-vascularisation than control group. Interestingly, multinucleated myotubes and myofibers were only detected in cell-seeded group. This study demonstrated that myoblast-seeded-bovine tunica vaginalis can be used as an effective scaffold to repair severe and large abdominal wall defects with regeneration of skeletal muscle tissue. PMID:20135201

Ayele, T; Zuki, A B Z; Noorjahan, B M A; Noordin, M M

2010-05-01

107

The Effect of Abdominal Bracing in Combination with Low Extremity Movements on Changes in Thickness of Abdominal Muscles and Lumbar Strength for Low Back Pain  

PubMed Central

[Purpose] The purpose of this study was to investigate the effects of abdominal bracing with low extremity movement on changes in thickness of abdominal muscles and lumbar strength. [Subjects] Sixteen patients with chronic low back pain were randomly assigned to two groups: an abdominal bracing with active straight leg raise (ABSLR) group and abdominal bracing with ankle dorsiflexion (ABDF) group. [Methods] All subjects were evaluated for their abdominal muscle strength using a MedX Lumbar Extension Machine and thickness of external oblique (EO), internal oblique (IO), and transverse abdominis (TrA) muscles using rehabilitative ultrasound imaging. Subjects in both groups were instructed to perform Abdominal bracing (AB). Simultaneously, those in the ABSLR group performed active SLR, and those in the ABDF group performed ankle dorsiflexion. [Results] In comparison between the ABSLR and ABDF groups, significant differences in the thickness of the IO and TrA muscles were observed after the intervention in the ABSLR group. Also, lumbar strength was showed a significant increase in both groups after interventions. [Conclusion] The results of this study demonstrated that ABSLR is a more effective method than ABDF for improvement of abdominal stabilization by increasing the thicknesses of the TrA and IO.

Lee, So Hee; Kim, Tae Hoon; Lee, Byoung Hee

2014-01-01

108

Ultrasonic Wall Thickness Monitoring at High Temperatures (>500 °C)  

NASA Astrophysics Data System (ADS)

Corrosion and erosion shorten the life of components that are used in the petrochemical industry. In order to mitigate the safety and financial risks posed by the degradation mechanisms, plant operators monitor wall thicknesses at regular inspection intervals. In high temperature locations inspections have to be carried out at plant shut downs because conventional ultrasonic sensors cannot withstand the high operating temperatures. The authors have developed a waveguide based high temperature thickness gauge for monitoring of wall thicknesses in high temperature areas. The waveguide allows the use of conventional transduction systems (max temp. 60 °C) at one end and guides ultrasonic waves into the high temperature region where the inspection is to be carried out. Slender stainless steel waveguides allow a temperature drop of ~500-600 °C per 200 mm length to be sustained simply by natural convection cooling. This paper describes the technical challenges that had to be overcome (dispersion and source/receiver characteristics) in order to implement this ``acoustic cable''. A range of experimental results of thickness measurements on components of different thickness, and furnace tests at different temperatures are presented. An accelerated corrosion test that demonstrates the effectiveness of the monitoring for corrosion is also presented.

Cegla, F. B.; Allin, J.; Davies, J. O.; Collins, P.; Cawley, P.

2011-06-01

109

The Limb-Abdominal Wall Complex Defects, a form of Amniotic Band Sydrome: A Rare Case Report.  

PubMed

The limb-body wall complex defects a form of amniotic band syndrome which consists of a polymal formation with a thoracic and /or an abdominal-schisis, eventration of the internal organ and anomalies of the extremities. We are presenting a case of a limb-body wall complex defect with the phenotype of a placenta-abdominal attachment, anomalies of the abdominal wall defect, absence of the right lower limb and genitourinary defects. PMID:23634417

Das, Sudhanshu Ku; Maharana, Sidharth Sankar; Subudhi, Monalisa; Rao, P V Subha

2013-03-01

110

The Limb-Abdominal Wall Complex Defects, a form of Amniotic Band Sydrome: A Rare Case Report  

PubMed Central

The limb-body wall complex defects a form of amniotic band syndrome which consists of a polymal formation with a thoracic and /or an abdominal-schisis, eventration of the internal organ and anomalies of the extremities. We are presenting a case of a limb-body wall complex defect with the phenotype of a placenta-abdominal attachment, anomalies of the abdominal wall defect, absence of the right lower limb and genitourinary defects.

Das, Sudhanshu Ku.; Maharana, Sidharth Sankar; Subudhi, Monalisa; Rao, P. V. Subha

2013-01-01

111

Multilayer injection moulding of thick-walled optical plastics parts  

NASA Astrophysics Data System (ADS)

Optical components are often thick-walled. The cycle time of precise polymer optics with a wall thickness of more than 20 mm exceeds several minutes. The multilayer injection moulding or compression moulding lowers the cycle time and increases the quality of the moulded parts. For the production of multilayer moulded lenses the mould design plays an important role. An innovative mould concept is presented with the possiblity to produce double or triple layer lenses. To ensure the quality and the endurance of multilayer moulded optical components in their applications, the cohesion in the interface is important. Tensile shear tests show the ability of multilayer moulded parts with high cohesion values for optical applications.

Hopmann, Ch.; Neuss, A.; Weber, M.; Walach, P.

2014-05-01

112

Leukoaraiosis is associated with arterial wall thickness: a quantitative analysis.  

PubMed

Leukoaraiosis refers to an age-related, abnormal appearance of the brain white matter on neuroimaging. The association between leukoaraiosis and cerebrovascular disease suggests that ischemia may be an important contributing factor; however, the pathogenesis of the condition remains controversial. We hypothesized that physical abnormalities of blood vessels might be culpable and compared the external and internal measurements of blood vessel walls between brains that demonstrated leukoaraiosis on imaging and normal control brains. Fourteen brains of individuals who had been diagnosed as having severe leukoaraiosis and five non-leukoaraiosis control brains were studied. Arterial cross-sections were evaluated by length measurements with an image analysis device. Arterial wall thickness and the ratio of the outer and inner diameters of the vessel were measured. We measured a total of 108 vessels in the leukoaraiosis group and 95 vessels in the control group. The vessel walls of the leukoaraiosis patients were an average of 5.5?µm thicker than the walls of control vessels of the same inside diameter (P?=?0.0000, 95% CI 3.01-8.08) and an average of 2.3?µm thicker than walls of control vessels of the same outside diameter (P?=?0.016, 95% CI 0.48-4.17). Our data provide evidence that leukoaraiosis is associated with vessel wall thickening in an additive fashion and indicate that structural vascular abnormalities are associated with leukoaraiosis. PMID:22017293

Auriel, Eitan; Csiba, Laszlo; Berenyi, Ervin; Varkonyi, Ildiko; Mehes, Gabor; Kardos, Laszlo; Karni, Arnon; Bornstein, Natan M

2012-06-01

113

Adiabatic shear banding in a thick-walled steel tube  

Microsoft Academic Search

We analyze the initiation and propagation of adiabatic shear bands in a thick-walled 4340 steel tube with a V-notch in the middle. The material is modeled as strain hardening, strain-rate hardening and thermal softening. The deformations\\u000a are assumed to be locally adiabatic and the effect of inertia forces is considered. Two different loadings, i.e., torsional,\\u000a and combined torsional and axial

R. C. Batra; D. Rattazzi

1997-01-01

114

Evaluation of UT Wall Thickness Measurements and Measurement Methodology  

SciTech Connect

CH2M HILL has requested that PNNL examine the ultrasonic methodology utilized in the inspection of the Hanford double shell waste tanks. Specifically, PNNL is to evaluate the UT process variability and capability to detect changes in wall thickness and to document the UT operator's techniques and methodology in the determination of the reported minimum and average UT data and how it compares to the raw (unanalyzed) UT data.

Weier, Dennis R.; Pardini, Allan F.

2007-10-01

115

Texture analysis improves level set segmentation of the anterior abdominal wall  

SciTech Connect

Purpose: The treatment of ventral hernias (VH) has been a challenging problem for medical care. Repair of these hernias is fraught with failure; recurrence rates ranging from 24% to 43% have been reported, even with the use of biocompatible mesh. Currently, computed tomography (CT) is used to guide intervention through expert, but qualitative, clinical judgments, notably, quantitative metrics based on image-processing are not used. The authors propose that image segmentation methods to capture the three-dimensional structure of the abdominal wall and its abnormalities will provide a foundation on which to measure geometric properties of hernias and surrounding tissues and, therefore, to optimize intervention.Methods: In this study with 20 clinically acquired CT scans on postoperative patients, the authors demonstrated a novel approach to geometric classification of the abdominal. The authors’ approach uses a texture analysis based on Gabor filters to extract feature vectors and follows a fuzzy c-means clustering method to estimate voxelwise probability memberships for eight clusters. The memberships estimated from the texture analysis are helpful to identify anatomical structures with inhomogeneous intensities. The membership was used to guide the level set evolution, as well as to derive an initial start close to the abdominal wall.Results: Segmentation results on abdominal walls were both quantitatively and qualitatively validated with surface errors based on manually labeled ground truth. Using texture, mean surface errors for the outer surface of the abdominal wall were less than 2 mm, with 91% of the outer surface less than 5 mm away from the manual tracings; errors were significantly greater (2–5 mm) for methods that did not use the texture.Conclusions: The authors’ approach establishes a baseline for characterizing the abdominal wall for improving VH care. Inherent texture patterns in CT scans are helpful to the tissue classification, and texture analysis can improve the level set segmentation around the abdominal region.

Xu, Zhoubing [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 (United States)] [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 (United States); Allen, Wade M. [Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States)] [Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States); Baucom, Rebeccah B.; Poulose, Benjamin K. [General Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37235 (United States)] [General Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37235 (United States); Landman, Bennett A. [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 and Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States)] [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 and Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States)

2013-12-15

116

Use of biological meshes for abdominal wall reconstruction in highly contaminated fields  

PubMed Central

Abdominal wall defects and incisional hernias represent a challenging problem. In particular, when a synthetic mesh is applied to contaminated wounds, its removal is required in 50%-90% of cases. Biosynthetic meshes are the newest tool available to surgeons and they could have a role in ventral hernia repair in a potentially contaminated field. We describe the use of a sheet of bovine pericardium graft in the reconstruction of abdominal wall defect in two patients. Bovine pericardium graft was placed in the retrorectus space and secured to the anterior abdominal wall using polypropylene sutures in a tension-free manner. We experienced no evidence of recurrence at 4 and 5 years follow-up.

Cavallaro, Andrea; Lo Menzo, Emanuele; Di Vita, Maria; Zanghi, Antonio; Cavallaro, Vincenzo; Veroux, Pier Francesco; Cappellani, Alessandro

2010-01-01

117

Anterior Abdominal Wall Leiomyoma Arising De Novo in a Perimenopausal Woman  

PubMed Central

Extrauterine or extraintestinal leiomyomas are extremely uncommon especially in the pre-peritoneal area or within the anterior abdominal wall muscles. These tumors have been ascribed to intraoperative seeding during resection of a fibroid or a leiomyoma of gut, to exogenous hormone replacement therapy or a major derangement of glucose and/or lipid metabolism. So far, there is no published report of de novo origin of anterior abdominal wall pure leiomyoma in the literature. The author herein reports a case of perimenopausal multiparous woman without any listing of previous gynecological surgery or hormone therapy who presented with a large pre-peritoneal intramuscular leiomyoma of the anterior abdominal wall. The patient underwent complete primary resection with amelioration of her symptoms.

Al-Wadaani, Hamed A.

2012-01-01

118

Paediatric abdominal wall hernia following handlebar injury: should we diagnose more and operate less?  

PubMed

Traumatic abdominal wall hernia following handlebar injury can be easily missed and is thus underreported. A 12-year-old boy presented with handlebar injury to the left upper quadrant of his abdomen. Except for a localised swelling, thought to be related to a haematoma, he was haemodynamically stable. CT revealed an abdominal wall defect with herniating fat that was not evident clinically and was also missed on immediate ultrasound examination. As there were no associated injuries and the abdominal wall defect was small without any herniating bowel loops, masterly inactivity was observed. After 6 weeks, the swelling has disappeared completely and there is progressive reduction in the size of the defect. PMID:23606382

Upasani, Anand; Bouhadiba, Nordeen

2013-01-01

119

Immediate reconstruction of full-thickness chest wall defects  

SciTech Connect

Twenty-one patients had full-thickness chest wall defects reconstructed at the New York University Medical Center in the last ten years. Marlex mesh provided chest wall stability in 5 patients. In 9 patients with radiation ulcers Marlex mesh was not required; a severe fibrotic reaction had obliterated the pleural space and prevented paradoxical motion. Partial sternal resections did not require Marlex stabilization, while a total sternectomy resulted in marked ventilatory insufficiency in a patient who would have benefited from the use of a stabilizing material. Random pattern flaps were used initially; more recently, axial pattern, myocutaneous, and myocutaneous free flaps were employed. Necrosis developed in 4 (36%) of the 11 patients with random pattern flaps, but was not seen with the newer flap techniques. Myocutaneous free flaps provided uncomplicated coverage of and stability to three large, potentially contaminated defects. It seems that with the currently available flap techniques and the methods of chest wall stabilization, immediate repair of all full-thickness chest wall defects is possible.

Boyd, A.D.; Shaw, W.W.; McCarthy, J.G.; Baker, D.C.; Trehan, N.K.; Acinapura, A.J.; Spencer, F.C.

1981-10-01

120

Expanded use of transplantation techniques: abdominal wall transplantation and intestinal autotransplantation.  

PubMed

Surgical principles and techniques derived from organ transplantation surgery can provide novel applications in general surgery. We present an update on our 5-year experience with intestinal autotransplantation and abdominal wall transplantation. Nine patients underwent intestinal or multivisceral transplantation with the addition of 10 abdominal wall grafts to cover the large open areas from previous surgeries. Seven patients underwent near-total abdominal evisceration, ex vivo resection of masses at the base of the mesentery, followed by intestinal autotransplantation; 44% of the abdominal wall graft recipients are alive, but none of the fatalities were related to the graft itself. In two cases the graft had to be removed due to venous thrombosis. Of patients with intestinal autotransplants, 71% are alive with two mortalities due to recurrent metastatic malignancy. In only one case, the intestinal autograft had to be removed because of venous thrombosis. All surviving patients but one are on a regular diet; two are on supplemental enteral feeds. These results show that anastomotic and resection techniques derived from the experience in solid organ transplant can be utilized in complex wound closure, as is the case of abdominal wall transplantation, or resection of large retroperitoneal tumors with intestinal autotransplantation. PMID:15251385

Selvaggi, G; Levi, D M; Kato, T; Madariaga, J; Moon, J; Nishida, S; Tzakis, A G

2004-06-01

121

Reducing Effective Liquid Wall Thickness in a HYLIFE-II Fusion Breeder  

Microsoft Academic Search

One of the major inertial fusion energy reactor designs is HYLIFE-II which uses protective flowing liquid wall between fusion plasma and solid first wall. The most attractive aspect of this reactor is that protective liquid wall eliminates the frequent replacement of the first wall structure during reactor lifetime. Liquid wall thickness must be at least the thickness required for supplying

Mustafa Übeyli

2004-01-01

122

Thick-wall effects in the theory of resistive wall modes  

SciTech Connect

Magnetic interaction of the plasma perturbations with the nearby resistive wall is considered as a resistive wall mode (RWM) problem, but with two essential differences from the traditional thin-wall approach. First, the wall is treated as magnetically thick, which means that the skin depth is not assumed larger than the wall thickness. Second, the plasma is allowed to enter the region where the RWM must be deeply unstable without rotation. The latter corresponds to the plasma operation above the no-wall stability limit demonstrated in the DIII-D tokamak [E. J. Strait et al., Phys. Plasmas 11, 2505 (2004)]. It is shown that the rotational stabilization observed in these experiments can be reproduced in this model if the mode is forced to rotate with a frequency above a critical level. The analytical estimates show that this effect (absent in the model based on the thin-wall approximation) is strong at realistic parameters. The model also predicts that the locking of the rotationally stabilized mode gives rise to instability with a growth rate much larger than its thin-wall estimate.

Pustovitov, V. D. [Institute of Tokamak Physics, National Research Centre 'Kurchatov Institute', Kurchatov Sq., 1, Moscow 123182 (Russian Federation)

2012-06-15

123

[Tension-free plasty in the surgery of abdominal wall hernias].  

PubMed

The article presents an experience with application of tension-free plasty of the anterior abdominal wall using reticular endoprostheses. New endoprostheses of Reperen are developed and applied, a method of sutureless fixation of polypropylene net in the abdominal wall tissues is proposed when performing plasty for great ventral hernias. Advantages of new methods are shown compared with analogs both in selective and in emergency surgery, in different age groups of patients. The direct and long-term postoperative results and parameters of quality of life are investigated. PMID:21137266

Parshikov, V V; Medvedev, A P; Samsonov, A A; Romanov, R V; Samsonov, A V; Gradusov, V P; Petrov, V V; Khodak, V A; Baburin, A B

2010-01-01

124

The abdominal wall lumps and bumps: cross-sectional imaging spectrum.  

PubMed

This article focuses on the cross-sectional imaging spectrum of abnormalities that affect the abdominal wall, with emphasis on magnetic resonance imaging (MRI). Cross-sectional imaging is valuable for diagnosing and evaluating the extent of abdominal-wall masses. With the increasing use of MRI, it is often possible to reach a diagnosis or narrow the differential diagnosis, thereby guiding effective management. Neoplastic and non-neoplastic pathologies will be illustrated, and the distinctive imaging characteristics of these entities will be highlighted. PMID:22884230

Virmani, Vivek; Sethi, Vineeta; Fasih, Najla; Ryan, John; Kielar, Ania

2014-02-01

125

Fungating carcinoma of the stomach: en bloc multiple organ resection and abdominal wall reconstruction.  

PubMed Central

A patient with carcinoma of the stomach invading multiple adjacent organs and fungating through the anterior abdominal wall was treated by en bloc multiple organ resection and abdominal wall reconstruction. The patient is alive and well at the time of writing, six months after the operation. The rationale for embarking on multiple organ resection for gastric cancer is discussed. However, such an aggressive surgical approach should only be applied to carefully selected patients who are medically fit and have no evidence of widespread systemic metastases. Images Figure

Chu, K. M.; Lai, D. T.; Stern, H. S.; Sheldon, D. M.

1995-01-01

126

The use of three different mesh materials in the treatment of abdominal wall defects.  

PubMed

Various prosthetic materials have been proposed for the repair of abdominal wall defects. These materials offer tension-free repair and significantly lower recurrence rate. Their respective properties are related to such complications as seroma, infection, fistula formation, intestinal adhesions and removal. We compared the final outcome in treating abdominal wall defects in 56 patients with three different prosthetic materials: conventional polypropylene in a preperitoneal location, expanded polytetrafluoroethylene mesh, and hydrophilic membrane coated polyester mesh in an intraperitoneal location. The hydrophilic coated polyester group exhibited the lowest complication rate and the polypropylene group the highest. PMID:12152638

Deligiannidis, N; Papavasiliou, I; Sapalidis, K; Kesisoglou, I; Papavramidis, S; Gamvros, O

2002-07-01

127

Comparison of abdominal muscle thickness with vaginal pressure changes in healthy women.  

PubMed

[Purpose] The purpose of this study was to verify the efficacy of a pelvic floor muscle exercise program by comparing subjects' muscle thickness with changes in vaginal pressure. [Subjects] Two groups of female participants without a medical history of pelvic floor muscle dysfunction were evaluated. The mean age of Group I was 33.5?years and that of Group II was 49.69?years. [Methods] The participants were instructed to perform a pelvic floor muscle contraction. While measuring the vaginal pressure of the pelvic floor muscle, biofeedback was given on five levels, and the thicknesses of the transversus abdominis, external oblique, and internal oblique muscles were measured with ultrasound. [Results] The thickness of the transversus abdominis muscle was significantly increased at 30 cmH2O in Group I, and at 20 cmH2O in Group II. The thickness of the internal oblique abdominal muscle significantly increased at maximum contraction in Group II. [Conclusion] Different abdominal muscles contracted depending on vaginal pressure. The result may be used to create and implement an exercise program that effectively strengthens the pelvic floor muscles. PMID:24707099

Kim, Bo-In; Hwang-Bo, Gak; Kim, Ha-Roo

2014-03-01

128

Impact of calcifications on patient-specific wall stress analysis of abdominal aortic aneurysms  

Microsoft Academic Search

As a degenerative and inflammatory desease of elderly patients, about 80% of abdominal aortic aneurysms (AAA) show considerable\\u000a wall calcification. Effect of calcifications on computational wall stress analyses of AAAs has been rarely treated in literature\\u000a so far. Calcifications are heterogeneously distributed, non-fibrous, stiff plaques which are most commonly found near the\\u000a luminal surface in between the intima and the

A. Maier; M. W. Gee; C. Reeps; H.-H. Eckstein; W. A. Wall

2010-01-01

129

Correlation of Fetal Abdominal Subcutaneous Tissue Thickness by Ultrasound to Predict Birth Weight  

PubMed Central

Introduction: Fetal growth abnormality is associated with changes in the soft tissue mass, which is decreased in growth restricted fetuses and increased in macrosomia. Objective: To correlate fetal abdominal subcutaneous tissue thickness (FASTT) measured by ultrasound at term and birth weight and to obtain a cut-off value of FASTT to predict large and small for gestational age babies in our population. Methods: FASTT was measured at the anterior 1/3rd of abdominal circumference by ultrasound after 36 weeks and weight of the baby measured after birth. Results:There was positive correlation between FASTT and birth weight. FASTT of 6.25 mm was sensitive to predict large for gestational age (LGA) babies and had a high negative predictive value; FASTT measurement for prediction of small babies with birth weight < 2500 g was not sensitive. Conclusion: FASTT can be used as an additional indicator to predict large for gestational age babies along with other known birth weight indicators.

Nathan, Anitha; R, Amar; Vasudeva, Akhila; Adiga, Prashanth; Bhat, Parvati V; Kumar N, Pratap

2014-01-01

130

Exercises to activate the deeper abdominal wall muscles: the Lewit: a preliminary study.  

PubMed

The abdominal wall is a prime target for therapeutic exercises aimed to prevent and rehabilitate low back pain and to enhance performance training. This study examined the "Lewit," a corrective exercise prescribed for several purposes, which is performed lying supine in a crook-lying position and involves forceful breathing. Muscle activation and lumbar posture were compared with bracing the abdominal wall (stiffening) with robust effort and "hollowing" (attempting to draw in the wall toward the naval) with robust effort. Eight healthy male volunteers with 6 channels of electromyography were collected by means of surface electrode pairs of the rectus abdominis, external oblique, and internal oblique (IO) together with lumbar motion. The Lewit exercise caused higher muscle activity in the deeper abdominal wall muscles, in particular the IO and by default the transverse abdominis were activated at 54% maximum voluntary contractions (MVCs) on average and 84% MVC peak with no change in spine posture to maintain the elastic equilibrium of the lumbar spine. The Lewit is a deep oblique muscle activation exercise, and the activation levels are of a sufficient magnitude for training muscle engrams. This information will assist strength and conditioning coaches with program design decisions where this corrective abdominal exercise may be considered for clients who elevate the ribcage during strength exertions, or for clients targeting the deep obliques. PMID:24345966

Badiuk, Boyd W N; Andersen, Jordan T; McGill, Stuart M

2014-03-01

131

Fine-needle aspiration cytology of abdominal wall endometriosis: a study of 10 cases.  

PubMed

While about 15% of menstruating women develop endometriosis, abdominal wall endometriosis is relatively rare. We present 10 cases of abdominal wall endometriosis diagnosed by fine-needle aspiration (FNA) cytology and confirmed by subsequent surgical excision. A palpable abdominal wall mass was the most common symptom, followed by pain. Nine cases were associated with previous surgery. The smear showed glandular epithelial cells and spindle or ovoid stromal cells accompanied by macrophages in eight cases. The nucleus was round-to-oval and the nucleolus was inconspicuous. Mitosis was not observed in any case. In two cases, which were suspicious of malignancy on FNA, the epithelial cells showed anisonucleosis, hyperchromasia, and small conspicuous nucleoli. The stromal cells were spindle or ovoid in shape, without metaplastic changes. Histiocytes were noted in nine cases and hemosiderin-laden histiocytes were noted in two cases. The proportion of inflammatory cells varied. FNA diagnosis of abdominal wall endometriosis is possible when the cytological features are interpreted cautiously, together with the patient's clinical history. An accurate diagnosis on FNA will prevent unnecessary surgery. PMID:21987456

Kim, Jung Yeon; Kwon, Ji Eun; Kim, Hyun-Jung; Park, Kyeongmee

2013-02-01

132

Mammary Silicone Granuloma. Migration of Silicone Fluid to Abdominal Wall and Inguinal Region.  

National Technical Information Service (NTIS)

Two and one-half years after having had silicone fluid injected into her breasts, a 22-year-old woman noticed two painful masses in the subcutaneous tissue of her abdominal wall. Similar lesions appeared four months later in both breasts and in the inguin...

C. Delage J. J. Shane F. B. Johnson

1973-01-01

133

A case of rheumatoid arthritis presenting with postherpetic neuralgia and abdominal-wall pseudohernia.  

PubMed

Postherpetic neuralgia is a common complication, while the postherpetic abdominal-wall pseudohernia (AWP) is a quite rare complication of herpes zoster (HZ). We report a patient >45 years of age with a history of rheumatoid arthritis (RA) who presented with two chronic HZ complications. A 75-year-old woman was admitted with neuralgia following cutaneous herpes zoster 6 weeks before. She was on long-term glucocorticoid, antimalarial and non-steroidal anti-inflammatory treatment. Confluent ulcers began to fill with granulation tissue, crusts, scars and skin discoloration in the area of the left T12-L2 dermatomes and reducible, painless swelling of the left flank, 20 × 20 cm, without palpable defect in abdominal-wall. There were typical joint deformity and positive rheumatoid factor. On neurological examination superficial abdominal reflexes were diminished in the left side, with hypesthesia of the overlying skin. Needle electromyography revealed denervational changes limited to the left-side muscles (on affected dermatomes T12-L2). Thoracoabdominal CT did not reveal the presence of existing hernia. There was an abdominal distension, the left abdominal-wall was thinner than the right side. The patient was treated with an oral preparation containing benfotiamine and vitamins B6 and B12, carbamazepine, amitriptyline, gabapentin, and local lidocaine. Skin rash left with scarring and pigmentary changes and the abdominal-wall swelling resolved within 8 months, however, the pain still persisted. To our best knowledge, this is the first observation of RA-associated postherpetic AWP. This rare motor complication appears to be self-limited with a good prognosis for recovery, while postherpetic neuralgia may require a combination of treatments for adequate pain relief. Older age, female sex, greater rash and acute pain severity are considered as risk factors associated with severe postherpetic neuralgia. In addition, patients with RA, mainly those treated with oral corticosteroids, are also at increased risk of HZ complications. PMID:20066424

Dobrev, Hristo P; Atanassova, Penka A; Sirakov, Vladimir N; Zisova, Lilia G

2012-06-01

134

Terahertz inline wall thickness monitoring system for plastic pipe extrusion  

NASA Astrophysics Data System (ADS)

Conventional and commercially available inline wall thickness monitoring systems for pipe extrusion are usually based on ultrasonic or x-ray technology. Disadvantages of ultrasonic systems are the usual need of water as a coupling media and the high damping in thick walled or foamed pipes. For x-ray systems special safety requirements have to be taken into account because of the ionizing radiation. The terahertz (THz) technology offers a novel approach to solve these problems. THz waves have many properties which are suitable for the non-destructive testing of plastics. The absorption of electrical isolators is typically very low and the radiation is non-ionizing in comparison to x-rays. Through the electromagnetic origin of the THz waves they can be used for contact free measurements. Foams show a much lower absorption in contrast to acoustic waves. The developed system uses THz pulses which are generated by stimulating photoconductive switches with femtosecond laser pulses. The time of flight of THz pulses can be determined with a resolution in the magnitude of several ten femtoseconds. Hence the thickness of an object like plastic pipes can be determined with a high accuracy by measuring the time delay between two reflections on materials interfaces e.g. at the pipe's inner and outer surface, similar to the ultrasonic technique. Knowing the refractive index of the sample the absolute layer thickness from the transit time difference can be calculated easily. This method in principle also allows the measurement of multilayer systems and the characterization of foamed pipes.

Hauck, J.; Stich, D.; Heidemeyer, P.; Bastian, M.; Hochrein, T.

2014-05-01

135

The influence of porosity on the integration histology of two polypropylene meshes for the treatment of abdominal wall defects in dogs  

Microsoft Academic Search

Two types of monofilament polypropylene mesh with different pore sizes, mass densities and burst strengths were used to repair\\u000a two identical paired full-thickness abdominal wall defects in ten dogs, in order to compare their integration histology 90 days\\u000a after implantation. On one side a standard mesh, Prolene® (Ethicon), was sutured to the borders of the defect, while on the other a

F. H. Greca; Z. A. Souza-Filho; A. Giovanini; M. R. Rubin; R. F. Kuenzer; F. B. Reese; L. M. Araujo

2008-01-01

136

Correlations of coronary plaque wall thickness with wall pressure and wall pressure gradient: a representative case study  

PubMed Central

Background There are two major hemodynamic stresses imposed at the blood arterial wall interface by flowing blood: the wall shear stress (WSS) acting tangentially to the wall, and the wall pressure (WP) acting normally to the wall. The role of flow wall shear stress in atherosclerosis progression has been under intensive investigation, while the impact of blood pressure on plaque progression has been under-studied. Method The correlations of wall thickness (WT) with wall pressure (WP, blood pressure on the lumen wall) and spatial wall pressure gradient (WPG) in a human atherosclerotic right coronary artery were studied. The pulsatile blood flow was simulated using a three dimensional mathematical model. The blood was treated as an incompressible viscous non-Newtonian fluid. The geometry of the artery was re-constructed using an in vivo intravascular ultrasound (IVUS) 44-slice dataset obtained from a patient with consent obtained. The WT, the WP and the WPG were averaged on each slice, respectively, and Pearson correlation analysis was performed on slice averaged base. Each slice was then divided into 8 segments and averaged vessel WT, WP and WPG were collected from all 352 segments for correlation analysis. Each slice was also divided into 2 segments (inner semi-wall of bend and outer semi-wall of bend) and the correlation analysis was performed on the 88 segments. Results Under mean pressure, the Pearson coefficient for correlation between WT and WP was r?=?? 0.52 (p?wall thickness correlated negatively with wall pressure (r?=??0.81 by slice) and positively with wall pressure gradient (r?=?0.45). The slice averaged WT has a strong linear relationship with the slice averaged WP. Large-scale patient studies are needed to further confirm our findings.

2012-01-01

137

Case of a sigmoid colon cancer with metachronous metastases to the mesorectum and the abdominal wall  

PubMed Central

Backround Sigmoid colon cancer metachronous metastases commonly occur in the liver and lungs with sporadic reports also to the spleen, stomach, thyroid gland, abdominal wall and upper urinary tract. This is a rare case of metachronous metastases invading the mesorectum and the abdominal wall. Case presentation A 72-year-old female underwent sigmoidectomy for stage I (T2N0 M0) sigmoid colon cancer in May 2008. In June 2009, an abdominal computed tomography scan revealed a tumor 2 cm in size at the lower anterior mesorectum and a second mass 2 cm in size at the anterior abdominal wall midline. Total colonoscopy showed no mucosal lesion. The serum carcinoembryonic antigen level was normal. A biopsy of the mesorectum tumor showed similar histologic characteristics with the primary tumor. Since no other site of recurrence was identified, an abdominoperineal resection was attempted. During the operation and after the removal of the incision recurrence, sinus bradycardia and signs of myocardial ischemia were noticed. A loop transverse colostomy was immediately perfomed and the operation was terminated. Postoperative cardiologic examination revealed an acute myocardium infract. Chemo-radiation of the mesorectum tumor and re-evaluation for surgical excision was decided. Conclusion Metachronous metastasis of the mesorectum from sigmoid colon cancer is extremely rare. Although patterns of lymphatic spread from rectal cancer to sigmoid colon have recently been demonstrated, there is no evidence of metachronous mesorectum invasion from sigmoid colon cancer. This could be the issue for future trials.

2010-01-01

138

Lipedema complicated by lymphedema of the abdominal wall and lower limbs.  

PubMed

We describe a 52 year-old woman in whom lymphedema primarily of the abdominal wall was superimposed on lipedema resulting in an abdomen of enormous dimensions with marked impairment of ambulation. Treatment consisted of preoperative compression of the legs by an external pneumatic device (Lympha-Press) followed by excision of the lymphedematous abdominal fat pad in conjunction with "debulking" of the right leg. The patient illustrates the extremes of lipedema complicated by lymphedema and the technical difficulties associated with its management. PMID:10897469

Zelikovski, A; Haddad, M; Koren, A; Avrahami, R; Loewinger, J

2000-06-01

139

The effects of abdominal draw-in maneuver and core exercise on abdominal muscle thickness and Oswestry disability index in subjects with chronic low back pain  

PubMed Central

The purpose of this study was to effects of abdominal draw-in maneuver and core exercise with 4 weeks using the musculoskeletal ultrasonography on muscle thickness and disability in subjects with low back pain. Twenty patients with nonspecific back pain (abdominal draw-in maneuver group: n= 10, core exercise group: n= 10) were recruited in the study. Both group received exercise intervention 3 times a week for 4weeks. The test were based on muscle thickness (transversus abdominis; Tra, internal oblique; IO and external oblique; EO), disability (Oswestry disability index; ODI) measured immediately before and after intervention. The data was measured by SPSS program 12.0 version and analyzed by Paired t-test and Independent t-test. The following results were obtained. The thickness of IO, EO for both group significantly improved except for muscle thickness of Tra. The ODI were significant difference for both groups. As the results of this study, we suggest that it may be effective method to apply to increase for the thickness of Tra, EO using abdominal draw-in maneuver and thickness of IO using core exercise.

Park, Seong-Doo; Yu, Seong-Hun

2013-01-01

140

Histological characteristics of the abdominal aortic wall in patients with vascular chronic Q fever.  

PubMed

The aim of this study was to describe specific histological findings of the Coxiella burnetii-infected aneurysmal abdominal aortic wall. Tissue samples of the aneurysmal abdominal aortic wall from seven patients with chronic Q fever and 15 patients without evidence of Q fever infection were analysed and compared. Chronic Q fever was diagnosed using serology and tissue PCR analysis. Histological sections were stained using haematoxylin and eosin staining, Elastica van Gieson staining and immunohistochemical staining for macrophages (CD68), T lymphocytes (CD3), T lymphocyte subsets (CD4 and CD8) and B lymphocytes (CD20). Samples were scored by one pathologist, blinded for Q fever status, using a standard score form. Seven tissue samples from patients with chronic Q fever and 15 tissue samples from patients without Q fever were collected. Four of seven chronic Q fever samples showed a necrotizing granulomatous response of the vascular wall, which was characterized by necrotic core of the arteriosclerotic plaque (P = 0.005) and a presence of high numbers of macrophages in the adventitia (P = 0.007) distributed in typical palisading formation (P = 0.005) and surrounded by the presence of high numbers of T lymphocytes located diffusely in media and adventitia. Necrotizing granulomas are a histological finding in the C. burnetii-infected aneurysmal abdominal aortic wall. Chronic Q fever should be included in the list of infectious diseases with necrotizing granulomatous response, such as tuberculosis, cat scratch disease and syphilis. PMID:24953727

Hagenaars, Julia C J P; Koning, Olivier H J; van den Haak, Ronald F F; Verhoeven, Bart A N; Renders, Nicole H M; Hermans, Mirjam H A; Wever, Peter C; van Suylen, Robert Jan

2014-08-01

141

Stress intensity factors in a reinforced thick-walled cylinder  

NASA Technical Reports Server (NTRS)

An elastic thick-walled cylinder containing a radial crack is considered. It is assumed that the cylinder is reinforced by an elastic membrane on its inner surface. The model is intended to simulate pressure vessels with cladding. The formulation of the problem is reduced to a singular integral equation. Various special cases including that of a crack terminating at the cylinder-reinforcement interface are investigated and numerical examples are given. Results indicate that in the case of the crack touching the interface the crack surface displacement derivative is finite and consequently the stress state around the corresponding crack tip is bounded; and generally, for realistic values of the stiffness parameter, the effect of the reinforcement is not very significant.

Tang, R.; Erdogan, F.

1984-01-01

142

The logic behind thick, liquid-walled, fusion concepts  

NASA Astrophysics Data System (ADS)

It may be possible to surround the region where fusion reactions are taking place with a neutronically thick liquid blanket which has penetrations that allow only a few tenths of a percent of the neutrons to leak out. Even these neutrons can be attenuated by adding an accurately placed liquid or solid near the target to shadow-shield the beam ports from line-of-sight neutrons. The logic of such designs are discussed and their evolution is described with examples applied to both magnetic and inertial fusion (HYLIFE-II). These designs with liquid protection are self healing when exposed to pulsed loading and have a number of advantages-over the usual designs with solid first walls. For example, the liquid-protected solid components will last the life of the plant, and therefore the capacity factor is estimated to be approximately 10% higher than for the non-liquid-walled blankets, because no blanket replacement shutdowns are required. The component replacement, operations, and maintenance costs might be half the usual value because no blanket change-out costs or accompanying facilities are required. These combined savings might lower the cost of electricity by 20%. Nuclear-grade construction should not be needed, largely because the liquid attenuates neutrons and results in less activation of materials. Upon decommissioning, the reactor materials should qualify for disposal by shallow burial even when constructed of ordinary 304 stainless steel. The need for a high-intensity 14-MeV neutron test facility to develop first-wall materials is avoided or greatly reduced, saving billions of development dollars. Flowing molten Li, the molten salt Flibe (Li2BeF4), and molten Lil7Pb83 have been considered. An advantage of molten salt is that it will not burn and has a low tritium solubility and therefore low tritium inventory.

Moir, R. W.

1994-04-01

143

The logic behind thick, liquid-walled, fusion concepts  

SciTech Connect

It may be possible to surround the region where fusion reactions are taking place with a neutronically thick liquid blanket which has penetrations that allow only a few tenths of a percent of the neutrons to leak out. Even these neutrons can be attenuated by adding an accurately placed liquid or solid near the target to shadow-shield the beam ports from line-of-sight neutrons. The logic of such designs are discussed and their evolution is described with examples applied to both magnetic and inertial fusion (HYLIFE-II). These designs with liquid protection are self healing when exposed to pulsed loading and have a number of advantages-over the usual designs with solid first walls. For example, the liquid-protected solid components will last the life of the plant, and therefore the capacity factor is estimated to be approximately 10% higher than for the non-liquid-walled blankets, because no blanket replacement shutdowns are required. The component replacement, operations, and maintenance costs might be half the usual value because no blanket change-out costs or accompanying facilities are required. These combined savings might lower the cost of electricity by 20%. Nuclear-grade construction should not be needed, largely because the liquid attenuates neutrons and results in less activation of materials. Upon decommissioning, the reactor materials should qualify for disposal by shallow burial even when constructed of ordinary 304 stainless steel. The need for a high-intensity 14-MeV neutron test facility to develop first-wall materials is avoided or greatly reduced, saving billions of development dollars. Flowing molten Li, the molten salt Flibe (Li{sub 2}BeF{sub 4}), and molten Li{sub l7}Pb{sub 83} have been considered. An advantage of molten salt is that it will not burn and has a low tritium solubility and therefore low tritium inventory.

Moir, R.W.

1994-04-15

144

A new description of the anterior abdominal wall in man and mammals.  

PubMed Central

The ventral abdominal walls of 116 specimens (41 human and 75 from nine mammalian families) of various ages and both sexes were studied anatomically and histologically. In man, each abdominal aponeurosis was bilaminar, and each wall of the rectus sheath was trilaminar (plywood-like). The two layers of the internal oblique emerged, in part of its extent, superficial to the external oblique and also passed deep to the transversus abdominis. All the six aponeurotic layers were oblique and crossed the mid-line, forming the following digastric muscles: the two external obliques together, the two transversus abdominis muscles together, one internal oblique (anterior layer) with the opposite external oblique (posterior layer) and one internal oblique (posterior layer) with the opposite transversus abdominis (anterior layer). The linea alba might be considered less the insertion of the abdominal muscles, but rather the common area of decussation of their intermediate aponeuroses. In all mammals, the internal oblique aponeurosis passed either superficial to that of the external oblique or deep to that of the transversus. The transversus aponeurosis was always oblique and in all eutheria it split into two layers. All abdominal aponeuroses crossed the middle line forming digastric muscles between the two sides. The functional significance and surgical application of these findings are discussed. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15

Rizk, N N

1980-01-01

145

Abdominal wall defects: autopsy findings of distinct groups suggest different pathogenetic mechanisms.  

PubMed

Central and lateral abdominal wall defects are probably distinct and likely arise from different pathogenetic mechanisms. An autopsy study was done using data from a total of 45 central and lateral abdominal wall defect cases to evaluate if they are indeed separate entities and to suggest possible mechanisms involved in their formation. Central defects were found to be statistically different from lateral defects; malformations that co-existed with central defects were mainly bilateral and internal and also involved "inferior" organs in relation to fetal-embryonal blood flow. Patients with lateral defects were more often female, and their coexistent defects were usually unilateral and external, with only 1 defect occurring in an "inferior" organ. These results indicate mechanisms of a vascular perfusion deficit for the majority of the central defects and of external disruption for the lateral defects. PMID:18563957

Giménez-Scherer, Juan Antonio; Davies, Belinda R; Reséndiz-Morán, Mario A; Durán-Padilla, Marco A

2009-01-01

146

Biological and biomechanical assessment of a long-term bioresorbable silk-derived surgical mesh in an abdominal body wall defect model  

Microsoft Academic Search

Background  The patient’s own repair of a body wall defect would be enhanced by a mechanically robust, physically tailorable, bioresorbable\\u000a mesh scaffold that: (1) supports rapid host tissue ingrowth and development, while (2) reducing the complications associated\\u000a with permanent synthetic and allogenic and xenogenic biological implants.\\u000a \\u000a \\u000a \\u000a Methods  A full-thickness 1-cm-diameter abdominal wall defect was made in 36 Sprague–Dawley rats, which were divided

R. L. Horan; D. S. Bramono; J. R. L. Stanley; Q. Simmons; J. Chen; H. E. Boepple; G. H. Altman

2009-01-01

147

Current practice of abdominal wall closure in elective surgery - Is there any consensus?  

PubMed Central

Background Development of incisional hernia after open abdominal surgery remains a major cause of post-operative morbidity. The aim of this study was to determine the current practice of surgeons in terms of access to and closure of the abdominal cavity in elective open surgery. Methods Twelve surgical departments of the INSECT-Trial group documented the following variables for 50 consecutive patients undergoing abdominal surgery: fascial closure techniques, applied suture materials, application of subcutaneous sutures, subcutaneous drains, methods for skin closure. Descriptive analysis was performed and consensus of treatment variables was categorized into four levels: Strong consensus >95%, consensus 75–95%, overall agreement 50–75%, no consensus <50%. Results 157 out of 599 patients were eligible for analysis (85 (54%) midline, 54 (35%) transverse incisions). After midline incisions the fascia was closed continuously in 55 patients (65%), using slowly absorbable (n = 47, 55%), braided (n = 32, 38%) sutures with a strength of 1 (n = 48, 57%). In the transverse setting the fascia was closed continuously in 39 patients (72%) with slowly absorbable (n = 22, 41%) braided sutures (n = 27, 50%) with a strength of 1 (n = 30, 56%). Conclusion In the present evaluation midline incision was the most frequently applied access in elective open abdominal surgery. None of the treatments for abdominal wall closure (except skin closure in the midline group) is performed on a consensus level.

Rahbari, Nuh N; Knebel, Phillip; Diener, Markus K; Seidlmayer, Christoph; Ridwelski, Karsten; Stoltzing, Hartmut; Seiler, Christoph M

2009-01-01

148

Total transvaginal endoscopic abdominal wall hernia repair: a NOTES survival study  

Microsoft Academic Search

Hypothesis Natural orifice transluminal endoscopic surgery (NOTES) has gained widespread interest as a potentially less invasive alternative\\u000a to laparoscopic surgery or, else, an evolution as the next-generation surgery. The main objective of this study was to assess\\u000a the safety of transluminal abdominal wall hernia repair for potential human application by specifically investigating the\\u000a feasibility and challenges of using a transvaginal

D. Lomanto; U. Dhir; J. B. Y. So; W. K. Cheah; M. A. Moe; K. Y. Ho

2009-01-01

149

Aesthetic and Functional Abdominal Wall Reconstruction After Multiple Bowel Perforations Secondary to Liposuction  

Microsoft Academic Search

This report describes a case of aesthetic and functional abdominal wall reconstruction performed to salvage a deformed, scarred,\\u000a and herniated anterior abdomen after severe peritonitis and partial rectus muscle necrosis secondary to multiple bowel perforations\\u000a sustained during liposuction performed in a cosmetic clinic. The diagnosis of intestinal perforation was missed intraoperatively\\u000a and in the immediate postoperative period. The patient was

Michele Di Candia; Charles M. Malata

2011-01-01

150

A case of rheumatoid arthritis presenting with postherpetic neuralgia and abdominal-wall pseudohernia  

Microsoft Academic Search

Postherpetic neuralgia is a common complication, while the postherpetic abdominal-wall pseudohernia (AWP) is a quite rare\\u000a complication of herpes zoster (HZ). We report a patient >45 years of age with a history of rheumatoid arthritis (RA) who presented\\u000a with two chronic HZ complications. A 75-year-old woman was admitted with neuralgia following cutaneous herpes zoster 6 weeks\\u000a before. She was on long-term glucocorticoid,

Hristo P. Dobrev; Penka A. Atanassova; Vladimir N. Sirakov; Lilia G. Zisova

151

Regions of high wall stress can predict the future location of rupture of abdominal aortic aneurysm.  

PubMed

Predicting the wall stress in abdominal aortic aneurysm (AAA) using computational modeling may be a useful adjunct to traditional clinical parameters that indicate the risk of rupture. Maximum diameter has been shown to have many limitations, and using current technology it is possible to provide a patient-specific computational risk assessment using routinely acquired medical images. We present a case of AAA rupture where the exact rupture point was clearly visible on the computed tomography (CT) images. A blind computational study based on CT scans acquired 4 months earlier predicted elevated wall stresses in the same region that later experienced rupture. PMID:24554200

Doyle, Barry J; McGloughlin, Timothy M; Miller, Karol; Powell, Janet T; Norman, Paul E

2014-06-01

152

The "sliding door" technique for closure of abdominal wall defects after rectus abdominis musculocutaneous flap transposition.  

PubMed

Radical surgery is often necessary in patients with local recurrence of rectal cancer or in those with carcinoma associated with an anal fistula. The surgery may include extended excision of the perineal area and can create a large dead space in the pelvis and a large skin defect, often necessitating reconstruction of the pelvic floor using rectus abdominis musculocutaneous (RAM) flap transposition. Wound dehiscence and incisional hernia are common complications of RAM flap transposition. We report herein our encounter with 3 patients in whom we used a "sliding door" technique for reconstruction of the abdominal wall after the creation of a RAM flap. One patient underwent abdominoperineal resection with sacrectomy and RAM flap transposition; he experienced a postoperative surgical site infection and wound dehiscence, which we urgently repaired by reconstructing the abdominal wall using the sliding door technique. Two other patients underwent posterior pelvic exenteration with sacrectomy and RAM flap transposition. These patients underwent simultaneous abdominal wall reconstruction using the sliding door technique. No patient experienced postoperative pelvic sepsis, wound dehiscence, or incisional hernia. The sliding door technique might be useful for preventing wound dehiscence and incisional hernia in patients undergoing RAM flap transposition. PMID:24394135

Nakamoto, Takayuki; Koyama, Fumikazu; Kobata, Yasunori; Nagao, Mitsuo; Nakagawa, Tadashi; Nakamura, Shinji; Ueda, Takeshi; Nishigori, Naoto; Inoue, Takashi; Kawasaki, Keijiro; Obara, Shinsaku; Fujii, Hisao; Kido, Akira; Koizumi, Munehisa; Tanaka, Yasuhito; Nakajima, Yoshiyuki

2013-11-01

153

Evolution of the wall shear stresses during the progressive enlargement of symmetric abdominal aortic aneurysms  

NASA Astrophysics Data System (ADS)

The changes in the evolution of the spatial and temporal distribution of the wall shear stresses (WSS) and gradients of wall shear stresses (GWSS) at different stages of the enlargement of an abdominal aortic aneurysm (AAA) are important in understanding the aetiology and progression of this vascular disease since they affect the wall structural integrity, primarily via the changes induced on the shape, functions and metabolism of the endothelial cells. Particle image velocimetry (PIV) measurements were performed in in vitro aneurysm models, while changing their geometric parameters systematically. It has been shown that, even at the very early stages of the disease, i.e. increase in the diameter ? 50%, the flow separates from the wall and a large vortex ring, usually followed by internal shear layers, is created. These lead to the generation of WSS that drastically differ in mean and fluctuating components from the healthy vessel. Inside the AAA, the mean WSS becomes negative along most of the aneurysmal wall and the magnitude of the WSS can be as low as 26% of the value in a healthy abdominal aorta.

Salsac, A.-V.; Sparks, S. R.; Chomaz, J.-M.; Lasheras, J. C.

2006-08-01

154

Impact of poroelasticity of intraluminal thrombus on wall stress of abdominal aortic aneurysms  

PubMed Central

Background The predictions of stress fields in Abdominal Aortic Aneurysm (AAA) depend on constitutive descriptions of the aneurysm wall and the Intra-luminal Thrombus (ILT). ILT is a porous diluted structure (biphasic solid–fluid material) and its impact on AAA biomechanics is controversially discussed in the literature. Specifically, pressure measurements showed that the ILT cannot protect the wall from the arterial pressure, while other (numerical and experimental) studies showed that at the same time it reduces the stress in the wall. Method To explore this phenomenon further a poroelastic description of the ILT was integrated in Finite Element (FE) Models of the AAA. The AAA model was loaded by a pressure step and a cyclic pressure wave and their transition into wall tension was investigated. To this end ILT’s permeability was varied within a microstructurally motivated range. Results The two-phase model verified that the ILT transmits the entire mean arterial pressure to the wall while, at the same time, it significantly reduces the stress in the wall. The predicted mean stress in the AAA wall was insensitive to the permeability of the ILT and coincided with the results of AAA models using a single-phase ILT description. Conclusion At steady state, the biphasic ILT behaves like a single-phase material in an AAA model. Consequently, computational efficient FE single-phase models, as they have been exclusively used in the past, accurately predict the wall stress in AAA models.

2012-01-01

155

The quasi-static failure properties of the abdominal aortic aneurysm wall estimated by a mixed experimental-numerical approach.  

PubMed

Assessing the risk for abdominal aortic aneurysm (AAA) rupture is critical in the management of aneurysm patients and an individual assessment is possible with the biomechanical rupture risk assessment. Such an assessment could potentially be improved by a constitutive AAA wall model that accounts for irreversible damage-related deformations. Because of that the present study estimated the elastic and inelastic properties of the AAA wall through a mixed experimental-numerical approach. Specifically, finite element (FE) models of bone-shaped tensile specimens were used to merge data from failure testing of the AAA wall with their measured collagen orientation distribution. A histo-mechanical constitutive model for collagen fibers was employed, where plastic fibril sliding determined not only remaining deformations but also weakening of the fiber. The developed FE models were able to replicate the experimentally recorded load-displacement property of all 16 AAA wall specimens that were investigated in the study. Tensile testing in longitudinal direction of the AAA defined a Cauchy strength of 569(SD 411) kPa that was reached at a stretch of 1.436(SD 0.118). The stiffness and strength of specimens decreased with the wall thickness and were elevated (p = 0.018; p = 0.030) in patients with chronic obstructive pulmonary disease (COPD). Smoking affected the tissue parameters that were related to the irreversible deformation response, and no correlation with gender and age was found. The observed effects on the biomechanical properties of the AAA wall could have long-term consequences for the management of aneurysm patients, i.e., specifically they might influence future AAA rupture risk assessments. However, in order to design appropriate clinical validation studies our findings should firstly be verified in a larger patient cohort. PMID:23263935

Forsell, Caroline; Swedenborg, Jesper; Roy, Joy; Gasser, T Christian

2013-07-01

156

Impairment of Lung and Chest Wall Mechanics in Patients with Acute Respiratory Distress Syndrome Role of Abdominal Distension  

Microsoft Academic Search

Recent data have suggested that the elastic properties of the chest wall (CW) may be compromised in patients with ARDS because of abdominal distension (4). We partitioned CW and lung (L) mechan- ics, assessed the role of abdominal distension, and verified whether the underlying disease responsi- ble for ARDS affects the impairment of respiratory mechanics. Volume-pressure (V-P) curves (inter- rupter

V. MARCO RANIERI; NICOLA BRIENZA; SERGIO SANTOSTASI; FILOMENA PUNTILLO; LUCIANA MASCIA; NICOLA VITALE; ROCCO GIULIANI; VINCENZO MEMEO; FRANCESCO BRUNO; TOMMASO FIORE; ANTONIO BRIENZA; ARTHUR S. SLUTSKY

157

Evaluation of Seprafilm and Amniotic Membrane as Adhesion Prophylaxis in Mesh Repair of Abdominal Wall Hernia in Rats  

Microsoft Academic Search

Introduction: Adhesion formation following abdominal wall hernia repair with prosthetic mesh may lead to intestinal obstruction and enterocutaneous fistula. Physical barriers, namely, human amniotic membrane (HAM) or Seprafilm (Genzyme, Cambridge, Mass., USA), a bio-absorbable, translucent membrane composed of carboxymethylcellulose and hyaluronic acid, have been reported to prevent postsurgical intra-abdominal adhesions. Objective: Evaluating the effect of HAM and Seprafilm in preventing

A. Szabo; M. Haj; I. Waxsman; A. Eitan

2000-01-01

158

Successful MRI-Guided Focused Ultrasound Uterine Fibroid Treatment Despite an Ostomy and Significant Abdominal Wall Scarring  

PubMed Central

We present a case of successful magnetic resonance imaging-guided focused ultrasound surgery (MRgFUS) of a uterine fibroid in a patient with extensive anterior abdominal wall surgical scars from two longitudinal laparotomies, a total colectomy and ileostomy. This case demonstrates that MRgFUS can be safely used in patients with an ostomy and significant abdominal wall scarring, but careful pretreatment planning and positioning during treatment is needed.

Machtinger, Ronit; Tempany, Clare M. C.; Kanan Roddy, Angela; Fennessy, Fiona M.

2011-01-01

159

Fournier's gangrene - delayed pedicle flap based upon the anterior abdominal wall.  

PubMed

Introduction: Fournier's gangrene is a poly-microbial necrotizing fasciitis that involves the perineum and/or external genitalia. Urgent surgical debridement is well recognized as essential acute treatment yet unique challenges arise for plastic surgical reconstruction to obtain a complete functional recovery. This case describes a successful delayed pedicle flap repair based upon the anterior abdominal wall. Case description: A 24 year old man was admitted to ICU ten days after elective circumcision with Fournier's gangrene. He underwent a number of surgical debridements, and was referred for plastic surgical management. He had penile reconstruction using a random pattern abdominal flap, which was performed as a three stage procedure including flap vascular delay technique. Discussion: Perineal and penile skin loss can be significant and is difficult to repair. Various techniques have been used to reconstruct lost tissue: skin grafts, transposition of the testes and spermatic cords to the thigh, flaps, and other types of pediculated myocutaneous flaps. Muscle flap reconstruction provides an environment that allows for complete regeneration of the urethral epithelium but is bulky and unsightly. Skin grafts contract and may produce painful and dysfunctional reconstructions. This novel technique produces a functional, and aesthetic reconstruction. Conclusion: Penile skin recovery following Fournier's gangrene recovery is problematic. This case demonstrates the functionality of a delayed flap repair using the anterior abdominal wall. PMID:25010310

Sliwinski, Ania; Kavanagh, Liam E; Bolton, Damien; Lawrentschuk, Nathan; Crock, John G

2014-01-01

160

Rejection of Permacol® mesh used in abdominal wall repair: A case report  

PubMed Central

Permacol® mesh has shown promise when used in abdominal wall repair, especially in the presence of a contaminated surgical field. This biomaterial, derived from porcine dermis collagen, has proposed advantages over synthetic materials due to increased biocompatibility and reduced foreign body reaction within human tissues. However, we present a case report describing a patient who displayed rejection to a Permacol® mesh when used in the repair of abdominal wound dehiscence following an emergency laparotomy. Review of the English language literature using PubMed and Medline, showed only two previously published cases of explantation of Permacol® due to sepsis or wound breakdown. The authors believe this is the first case of severe foreign body reaction leading to rejection of Permacol®. Both animal and human studies show conflicting evidence of biocompatibility. There are several reports of successful use of Permacol® to repair complex incisional herniae or abdominal walls in the presence of significant contamination. It appears from the literature that Permacol® is a promising material, but as we have demonstrated, it has the potential to evoke a foreign body reaction and rejection in certain subjects.

Wotton, Franchesca T; Akoh, Jacob A

2009-01-01

161

Complex Abdominal Wall Reconstruction: A Comparison of Flap and Mesh Closure  

PubMed Central

Objective To analyze a series of patients treated for recurrent or chronic abdominal wall hernias and determine a treatment protocol for defect reconstruction. Summary Background Data Complex or recurrent abdominal wall defects may be the result of a failed prior attempt at closure, trauma, infection, radiation necrosis, or tumor resection. The use of prosthetic mesh as a fascial substitute or reinforcement has been widely reported. In wounds with unstable soft tissue coverage, however, the use of prosthetic mesh poses an increased risk for extrusion or infection, and vascularized autogenous tissue may be required to achieve herniorrhaphy and stable coverage. Methods Patients undergoing abdominal wall reconstruction for 106 recurrent or complex defects (104 patients) were retrospectively analyzed. For each patient, hernia etiology, size and location, average time present, technique of reconstruction, and postoperative results, including recurrence and complication rates, were reviewed. Patients were divided into two groups based on defect components: Type I defects with intact or stable skin coverage over hernia defect, and Type II defects with unstable or absent skin coverage over hernia defect. The defects were also assigned to one of the following zones based on primary defect location to assist in the selection and evaluation of their treatment: Zone 1A, upper midline; Zone IB, lower midline; Zone 2, upper quadrant; Zone 3, lower quadrant. Results A majority of the defects (68%) were incisional hernias. Of 50 Type I defects, 10 (20%) were repaired directly, 28 (56%) were repaired with mesh only, and 12 (24%) required flap reconstruction. For the 56 Type II defects reconstructed, flaps were used in the majority of patients (n = 48; 80%). The overall complication and recurrence rates for the series were 29% and 8%, respectively. Conclusions For Type I hernias with stable skin coverage, intraperitoneal placement of Prolene mesh is preferred, and has not been associated with visceral complications or failure of hernia repair. For Type II defects, the use of flaps is advisable, with tensor fascia lata representing the flap of choice, particularly in the lower abdomen. Rectus advancement procedures may be used for well-selected midline defects of either type. The concept of tissue expansion to increase both the fascial dimensions of the flap and zones safely reached by flap transposition is introduced. Overall failure is often is due to primary closure under tension, extraperitoneal placement of mesh, flap use for inappropriate zone, or technical error in flap use. With use of the proposed algorithm based on defect analysis and location, abdominal wall reconstruction has been achieved in 92% of patients with complex abdominal defects.

Mathes, Stephen J.; Steinwald, Paul M.; Foster, Robert D.; Hoffman, William Y.; Anthony, James P.

2000-01-01

162

The use of prosthesis in abdominal and thoracic wall defect, 15 year experience: evaluation of tissue reactions and complications.  

PubMed

Synthetic prosthesis (Polypropylene, Dacron and expanded Polyterafluoroethylene) is now widely used in abdominal and thoracic wall reconstructive surgery. Many surgeons have reported great success with various types of prosthetic implants but tissue reactions and other complications have never been well defined. The aim of this study was to determine which molecules react upon tissue contact, which synthetic materials result in less complications and whether some non-specialized prosthetics are correlated with certain types of complications. We studied 54 patients from 1982-1997 who had each been re-operated on for prosthetic complications. Our clinical data was then compared to data collected from animal models. Twenty-one pigs received one or more prosthetic implants: 14 of these pigs received their implants with a "proper surgical technique" while 8 underwent "improper surgical technique". The results from both the clinical and animal study were significantly similar. From a microscopic point of view, we can conclude that different tissues react in the same way with the same or similar types of prostheses. The reactions begin to differ when the thickness and rigidity of the material is considered. A PTFE-polyporpylene combination (Composix Mesh) seems to be the most effective solution, especially in abdominal defect repair which involves peritoneal organ contact. We would also like to emphasize that prosthetic complications can be quite serious and this type of procedure should only be performed by experienced and qualified surgeons. PMID:10514913

Francioni, G; Ansaldo, V; Magistrelli, P; Pari, A M; Rinaldi, P; Sani, C; Rafaeli, W; Pari, G

1999-01-01

163

Domain wall structure in Permalloy films with decreasing thickness at the Bloch to Neel transition  

SciTech Connect

The Bloch to Neel wall transition is investigated in Permalloy films between 160 and 10 nm thickness using direct integration of the Landau{endash}Lifshitz{endash}Gilbert equation in a three-dimensional Cartesian lattice. At 80 nm, the wall is a symmetric Bloch wall characterized by two adjoining vortices with the magnetization at the wall center pointing perpendicular to the plane of the material throughout the thickness. The Bloch to Neel transition takes place between 35 and 30 nm, below which the wall becomes a symmetric Ne{prime}el wall. For the Bloch walls, our wall energy per unit area calculations match reasonably well the results of A. Hubert{close_quote}s Ritz method calculations [Magnetic Domains (Springer, New York, 1998), p. 251] and A. E. Labonte{close_quote}s numerical calculations [J. Appl. Phys. 40, 2450 (1969)]. For the Neel walls, however, our results indicate an approximately 70% higher energy for thicknesses of 30 nm and below, since the Neel wall tails are included. For thicknesses below 160 nm, the anisotropy energy component is low, and both C-shaped and symmetric Bloch walls are dominated by exchange interaction. As the wall transforms from Bloch to Neel below 35 nm, the energy contribution changes from 76% exchange and 24% demagnetization to 70% demagnetization and 30% exchange, respectively. Wall widths are computed for thicknesses between 10 and 640 nm along with the out-of-plane magnetization due to the presence of the vortex. {copyright} 2001 American Institute of Physics.

Trunk, T.; Redjdal, M.; Kakay, A.; Ruane, M. F.; Humphrey, F. B.

2001-06-01

164

Abdominal Wall Abscess due to Acute Perforated Sigmoid Diverticulitis: A Case Report with MDCT and US Findings  

PubMed Central

Perforation of the inflamed diverticula is a common diverticulitis complication. It usually leads to the formation of a local abscess. In some rare cases, the inflammatory process may spread towards extra-abdominal sites like the anterior or posterior abdominal wall or the thigh and form an abscess in these sites. We present the case of a 73-year-old man with a history of pain at the lower left quadrant of the abdomen for 20 days and a visible mass in this site. Ultrasonography and computed tomography revealed this mass to be an abscess of the abdominal wall which had been formed by the spread of ruptured sigmoid diverticulitis by continuity of tissue through the lower left abdominal wall. Local drainage of the abscess was performed and the patient was discharged after alleviation of symptoms and an uneventful course. We also discuss causes of abdominal wall abscesses along with the possible pathways by which an intra-abdominal abscess could spread outside the abdominal cavity.

Vasileios, Rafailidis; Anna, Gavriilidou; Christos, Liouliakis; Asimina, Tsimitri; Sofia, Paschaloudi; Vasiliki, Karadimou

2013-01-01

165

Spatial orientation of collagen fibers in the abdominal aortic aneurysm's wall and its relation to wall mechanics.  

PubMed

Collagen is the most abundant protein in mammals and provides the abdominal aortic aneurysm (AAA) wall with mechanical strength, stiffness and toughness. Specifically, the spatial orientation of collagen fibers in the wall has a major impact on its mechanical properties. Apart from valuable microhistological information, this data can be integrated by histomechanical constitutive models thought to improve biomechanical simulations, i.e. to improve the biomechanical rupture risk assessment of AAAs. Tissue samples (n = 24) from the AAA wall were harvested during elective AAA repair, fixated, embedded, sectioned and investigated by polarized light microscopy. The birefringent properties of collagen were reinforced by picrosirius red staining and the three-dimensional collagen fiber orientations were identified with a universal rotary stage. Two constitutive models for collagen fibers were used to integrate the identified structural information in a macroscopic AAA wall model. The collagen fiber orientation in the AAA wall was widely dispersed and could be captured by a Bingham distribution function (?(1) = 11.6, ?(2) = 9.7). The dispersion was much larger in the tangential plane than in the cross-sectional plane, and no significant difference between the medial and adventitial layers could be identified. The layered directional organization of collagen in normal aortas was not evident in the AAA. The collagen organization identified, combined with constitutive descriptions of collagen fibers that depend on its orientation, explain the anisotropic (orthotropic) mechanical properties of the AAA wall. The mechanical properties of collagen fibers depend largely on their undulation, which is an important structural parameter that requires further experimental investigation. PMID:22579983

Gasser, T Christian; Gallinetti, Sara; Xing, Xiao; Forsell, Caroline; Swedenborg, Jesper; Roy, Joy

2012-08-01

166

Left common iliac artery to inferior vena cava abdominal wall arteriovenous graft for hemodialysis access.  

PubMed

We describe a novel arteriovenous graft configuration in the abdominal wall for hemodialysis in a 51-year-old woman with sickle cell disease. Upper extremity access sites were exhausted, and intrathoracic central veins occluded. Because of diminished quality of the left groin due to scar tissue from previous infected access, inadequate vasculature, and the presence of functional femoral catheter in the right groin with common iliac vein stenosis, we decided to create an arteriovenous graft from the left common iliac artery to the inferior vena cava. Adequate thrill and uneventful postoperative recovery was observed. At 4 months, the patient has been successfully using her graft. PMID:22494692

Zamani, Nader; Anaya-Ayala, Javier E; Ismail, Nyla; Peden, Eric K

2012-08-01

167

Management of Anterior Abdominal Wall Defect Using a Pedicled Tensor Fascia Lata Flap: A Case Report  

PubMed Central

Degloving injuries to anterior abdominal wall are rare due to the mechanism of injury. Pedicled tensor fascia lata is known to be a versatile flap with ability to reach the lower anterior abdomen. A 34-year-old man who was involved in a road traffic accident presented with degloving injury and defect at the left inguinal region, sigmoid colon injury, and scrotal bruises. At investigation, he was found to have pelvic fracture. The management consisted of colostomy and tensor fascia lata to cover the defect at reversal. Though he developed burst abdomen on fifth postoperative day, the flap healed with no complications.

Ojuka, K. D.; Nangole, F.; Ngugi, M.

2012-01-01

168

PET/CT demonstration and monitoring of thoracic and abdominal wall mesothelioma.  

PubMed

Mesothelioma is a malignancy arising from the embryonic coelomic mesodermal lining forming the pleura, peritoneum, pericardium, and tunica vaginalis. It is mostly induced by exposure to asbestos. The author presents a 77-year-old woman with an atypical manifestation of epithelioid mesothelioma, which does not follow the expected clinical characteristics of this disease mentioned above. In this case, PET/CT provides useful information concerning the extension of the lesions to thoracic and abdominal walls not fully evaluated by the initial conventional cross-sectional imaging. PET/CT also allows an accurate therapeutic monitoring of the disease. PMID:23510890

Nguyen, Ba D

2014-01-01

169

Increased left ventricular torsion in hypertrophic cardiomyopathy mutation carriers with normal wall thickness  

Microsoft Academic Search

BACKGROUND: Increased left ventricular (LV) torsion has been observed in patients with manifest familial hypertrophic cardiomyopathy (HCM), and is thought to be caused by subendocardial dysfunction. We hypothesize that increased LV torsion is already present in healthy mutation carriers with normal wall thickness. METHODS: Seventeen carriers with an LV wall thickness <10 mm, and seventeen age and gender matched controls

Iris K Rüssel; Wessel P Brouwer; Tjeerd Germans; Paul Knaapen; J Tim Marcus; Jolanda van der Velden; Marco JW Götte; Albert C van Rossum

2011-01-01

170

Wall-Thickness Mastering of Computer-Assisted Gages. Final Report.  

National Technical Information Service (NTIS)

An alternate method of gage mastering and a device to verify the accuracy of wall thickness measurements were developed. These are used with computer-assisted gages that measure the contour and wall thickness of metal or plastic parts. A computer program ...

R. E. Hines

1982-01-01

171

Reducing Effective Liquid Wall Thickness in a HYLIFE-II Fusion Breeder  

NASA Astrophysics Data System (ADS)

One of the major inertial fusion energy reactor designs is HYLIFE-II which uses protective flowing liquid wall between fusion plasma and solid first wall. The most attractive aspect of this reactor is that protective liquid wall eliminates the frequent replacement of the first wall structure during reactor lifetime. Liquid wall thickness must be at least the thickness required for supplying sufficient tritium for the deuterium-tritium (DT) driver and satisfying radiation damage on the first wall below the limits. Reducing this thickness results less pumping power requirements and cost of electricity. In this study, investigation on potential of utilizing refractory alloys (W-5Re, TZM and Nb-1Zr) as first wall to reduce effective liquid wall thickness in HYLIFE-II reactor using liquid wall of Flibe + 10 mol % UF4 mixture. Neutron transport calculations were carried out with the help of the SCALE4.3 system by solving the Boltzmann transport equation with the XSDRNPM code in 238 neutron groups and a S8-P3 approximation. Numerical results showed that using W-5Re or TZM as first wall was effective in decreasing liquid wall thickness in contrast to Nb-1Zr.

Übeyli, Mustafa

2004-09-01

172

Comparison of the Abdominal Wall Stability of Endopath Optiview with the Standard Laparoscopic Cannula  

PubMed

We conducted a prospective trial to compare the intraabdominal wall stability of the sheath of the Endopath Optiview with that of a conventional reusable cannula. In 100 consecutive women undergoing elective laparoscopic sterilization in an ambulatory surgical unit, we alternately used a standard reusable 10-mm cannula (group A) or the Optiview 10- to 12-mm cannula (group B) to establish the intraabdominal surgical port. Single-incision bipolar laparoscopic tubal occlusion was performed, and the force required to remove the cannula sheath from the abdominal cavity was determined by spring-loaded force gauge. The mean (± SEM) peak force required to remove the cannula sheath in group A was 2.25 ± 0.19 lbs. The comparative value for group B was 5.32 ± 0.28 lbs. (p <0.005). The in situ operative sheath of the Endopath Optiview has greater intraabdominal wall stability than a standard reusable cannula. PMID:9074140

Kaali; Barad; Merkatz

1996-08-01

173

Minimizing abdominal wall damage during high-intensity focused ultrasound ablation by inducing artificial ascites.  

PubMed

High-intensity focused ultrasound (HIFU) is becoming an important tool for tumor treatment [especially hepatocellular carcinoma (HCC)] in Asian countries. A HIFU system provides unique advantages of low invasiveness and absence of nonradiation. However, if the target HCC is close to the proximal surface of the liver, HIFU may overheat diaphragm, abdominal wall or skin. To avoid this complication, a method using artificial ascites in the abdominal cavity to separate the liver from the peritoneum, and to serve as a heat sink to cool overlying structures and thereby avoid inducing permanent damage was proposed. Target tissue that was 10 mm below the liver surface was ablated in 12 New Zealand white rabbits: 6 in the experimental group and 6 in the control group. Artificial ascites was established in the experimental group by injecting normal saline into the abdominal cavity until the pressure reached 150 mm H2O. Artificial ascites not only reduced the probability and extent of thermal damage to intervening structures, but also had no adverse affect on the efficacy of HIFU ablation. PMID:18647009

Wu, Chih-Ching; Chen, Wen-Shiang; Ho, Ming-Chih; Huang, Kai-Wen; Chen, Chiung-Nien; Yen, Jia-Yush; Lee, Po-Huang

2008-07-01

174

Efficacy and safety of hyaluronate membrane in the rabbit cecum-abdominal wall adhesion model  

PubMed Central

Purpose Tissue adhesion is a well-known postsurgical phenomenon, causing pain, functional obstruction, and difficult reoperative surgery. To overcome these problems, various synthetic and natural polymer membranes have been developed as postoperative tissue adhesion barriers. However, limitation in their use has hindered its actual application. We prepared a hyaluronate membrane (HM) to evaluate its efficacy and safety as an adhesion barrier compared to a commercialized product (Interceed, Ethicon). Methods To evaluate the antiadhesion effect, a cecum-abdominal wall abrasion model was adopted in a rabbit. The denuded cecum was covered by Interceed or HM or neither and apposed to the abdominal wall (each, n = 10). Four weeks after surgery, the level of adhesion was graded. Acute and chronic toxicity of the three groups were also evaluated. Results Blood samples drawn to evaluate acute toxicity at postoperative day 3 and 7 showed no significant difference among the three groups. The grade and area of adhesion were significantly lower in the HM compared to those of the control and Interceed at four weeks after surgery. Histologic evaluations, which was carried out to estimate tissue reactions at the site of application, as well as to assess chronic toxicity for the major organs, were not significantly different in the three groups. Conclusion This study showed that the antiadhesion efficacy of HM was superior to commercialized antiadhesion membrane, Interceed. Low inflammatory response and nontoxicity were also demonstrated. From these results, we suggest that the HM is a good candidate as a tissue adhesion barrier.

Kim, Jae Young; Cho, Wan Jin; Kim, Jun Ho; Lim, Sae Hwan; Kim, Hyun Jung; Lee, Young Woo

2013-01-01

175

Architectural Analysis of Human Abdominal Wall Muscles: Implications for Mechanical Function  

PubMed Central

Study Design Cadaveric analysis of human abdominal muscle architecture. Objective To quantify the architectural properties of rectus abdominis (RA), external oblique (EO), internal oblique (IO) and transverse abdominis (TrA), and model mechanical function in light of these new data. Summary of Background Data Knowledge of muscle architecture provides the structural basis for predicting muscle function. Abdominal muscles greatly affect spine loading, stability, injury prevention and rehabilitation; however, their architectural properties are unknown. Methods Abdominal muscles from eleven elderly human cadavers were removed intact, separated into regions and micro-dissected for quantification of physiological cross-sectional area (PCSA), fascicle length and sarcomere length. From these data, sarcomere operating length ranges were calculated. Results IO had the largest PCSA and RA the smallest, and would thus generate the largest and smallest isometric forces, respectively. RA had the longest fascicle length, followed by EO, and would thus be capable of generating force over the widest range of lengths. Measured sarcomere lengths, in the post-mortem neutral spine posture, were significantly longer in RA and EO (3.29±0.07 and 3.18±0.11 ?m) compared to IO and TrA (2.61±0.06 and 2.58±0.05 ?m) (p < 0.0001). Biomechanical modeling predicted that RA, EO and TrA act at optimal force-generating length in the mid-range of lumbar spine flexion, where IO can generate approximately 90% of its maximum force. Conclusions These data provide clinically relevant insights into the ability of the abdominal wall muscles to generate force and change length throughout the lumbar spine range of motion. This will impact the understanding of potential postures in which the force-generating and spine stabilizing ability of these muscles become compromised, which can guide exercise/rehabilitation development and prescription. Future work should explore the mechanical interactions among these muscles and their relationship to spine health and function.

Brown, Stephen H. M.; Ward, Samuel R.; Cook, Mark S.; Lieber, Richard L.

2010-01-01

176

Domain wall structure in Permalloy films with decreasing thickness at the Bloch to Néel transition  

Microsoft Academic Search

The Bloch to Néel wall transition is investigated in Permalloy films between 160 and 10 nm thickness using direct integration of the Landau-Lifshitz-Gilbert equation in a three-dimensional Cartesian lattice. At 80 nm, the wall is a symmetric Bloch wall characterized by two adjoining vortices with the magnetization at the wall center pointing perpendicular to the plane of the material throughout

T. Trunk; M. Redjdal; A. Kákay; M. F. Ruane; F. B. Humphrey

2001-01-01

177

Patient-specific left atrial wall-thickness measurement and visualization for radiofrequency ablation  

NASA Astrophysics Data System (ADS)

INTRODUCTION: For radiofrequency (RF) catheter ablation of the left atrium, safe and effective dosing of RF energy requires transmural left atrium ablation without injury to extra-cardiac structures. The thickness of the left atrial wall may be a key parameter in determining the appropriate amount of energy to deliver. While left atrial wall-thickness is known to exhibit inter- and intra-patient variation, this is not taken into account in the current clinical workflow. Our goal is to develop a tool for presenting patient-specific left atrial thickness information to the clinician in order to assist in the determination of the proper RF energy dose. METHODS: We use an interactive segmentation method with manual correction to segment the left atrial blood pool and heart wall from contrast-enhanced cardiac CT images. We then create a mesh from the segmented blood pool and determine the wall thickness, on a per-vertex basis, orthogonal to the mesh surface. The thickness measurement is visualized by assigning colors to the vertices of the blood pool mesh. We applied our method to 5 contrast-enhanced cardiac CT images. RESULTS: Left atrial wall-thickness measurements were generally consistent with published thickness ranges. Variations were found to exist between patients, and between regions within each patient. CONCLUSION: It is possible to visually determine areas of thick vs. thin heart wall with high resolution in a patient-specific manner.

Inoue, Jiro; Skanes, Allan C.; White, James A.; Rajchl, Martin; Drangova, Maria

2014-03-01

178

Quantitative evaluation of abdominal wall perfusion after different types of laparotomy closure using laser-fluorescence videography.  

PubMed

Laparotomy closure relies on the incisional edges as anchor for the suture material. The results of these techniques are not satisfying, with failure rates of up to 20%. To investigate the effect of different conventional closure techniques and a novel "bridging technique" on abdominal wall perfusion an animal study was performed in rabbits. Abdominal wall perfusion was measured using the method of dynamic laser-fluorescence videography in the first 72 h of incisional wound healing in 25 animals. Suture tension was controlled with a water-filled polyurethane balloon connected to a pressure detector. The effect of laparotomy closure on abdominal wall tissue perfusion depends significantly on the applied technique and suture tension. Avoiding direct sutures in the incisional edges during laparotomy closure leads to a better tissue perfusion of the incisional region than conventional suture techniques. Suture tension can be controlled and adjusted using a water-filled polyurethane balloon as a pressure sensor. PMID:12090573

Höer, J; Töns, C; Schachtrupp, A; Anurov, M; Titkova, S; Oettinger, A; Wetter, O; Schumpelick, V

2002-03-01

179

Tension-free repair during extensive radical surgery for cecal cancer with abdominal wall invasion and inguinal lymph node metastasis  

PubMed Central

We report a case of cecal cancer with invasion of the abdominal wall and right inguinal lymph node metastasis. This patient had undergone an appendectomy 2 years previously. He underwent extensive radical right hemicolectomy with anastomosis and tension-free repair of the damaged right lower abdominal wall. The surgery progressed successfully, and the vital signs of the patient were stable (approximately 200 mL blood loss). Postoperative diagnosis revealed moderately to poorly differentiated adenocarcinoma of the cecum with invasion of the abdominal wall and metastasis of the inguinal lymph nodes (pT4bN2bM1, IV4a). The patient has remained well post-surgery.

Xu, Kaiwu; Chen, Zhihui; Song, Xinming

2014-01-01

180

New technical approach for the repair of an abdominal wall defect after a transverse rectus abdominis myocutaneous flap: a case report  

PubMed Central

Introduction Breast reconstruction with autologous tissue transfer is now a standard operation, but abnormalities of the abdominal wall contour represent a complication which has led surgeons to invent techniques to minimize the morbidity of the donor site. Case presentation We report the case of a woman who had bilateral transverse rectus abdominis myocutaneous flap (TRAM-flap) breast reconstruction. The surgery led to the patient developing an enormous abdominal bulge that caused her disability in terms of abdominal wall and bowel function, pain and contour. In the absence of rectus muscle, the large defect was repaired using a combination of the abdominal wall component separation technique of Ramirez et al and additional mesh augmentation with a lightweight, large-pore polypropylene mesh (Ultrapro®). Conclusion The procedure of Ramirez et al is helpful in achieving a tension-free closure of large defects in the anterior abdominal wall. The additional mesh augmentation allows reinforcement of the thinned lateral abdominal wall.

Kaemmer, Daniel A; Conze, Joachim; Otto, Jens; Schumpelick, Volker

2008-01-01

181

Method and apparatus for determining diameter and wall thickness of minute hollow spherical shells  

DOEpatents

Method and apparatus for determining diameter and wall thickness of hollow microspheres or shells wherein terminal velocities of shells traveling in fluid-filled conduits of differing diameters are measured. A wall-effect factor is determined as a ratio of the terminal velocities, and shell outside diameter may then be ascertained as a predetermined empirical function of wall-effect factor. For shells of known outside diameter, wall thickness may then be ascertained as a predetermined empirical function of terminal velocity in either conduit.

Steinman, David A. (Ann Arbor, MI)

1982-01-01

182

Method and apparatus for determining diameter and wall thickness of minute hollow spherical shells  

DOEpatents

Method and apparatus for determining diameter and wall thickness of hollow microspheres or shells wherein terminal velocities of shells traveling in fluid-filled conduits of differing diameters are measured. A wall-effect factor is determined as a ratio of the terminal velocities, and shell outside diameter may then be ascertained as a predetermined empirical function of wall-effect factor. For shells of known outside diameter, wall thickness may then be ascertained as a predetermined empirical function of terminal velocity in either conduit.

Steinman, D.A.

1980-05-30

183

Method of controlling the side wall thickness of a turbine nozzle segment for improved cooling  

DOEpatents

A gas turbine nozzle segment has outer and inner bands and a vane extending therebetween. Each band has a side wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band has an inturned flange defining with the nozzle wall an undercut region. The outer surface of the side wall is provided with a step prior to welding the cover to the side wall. A thermal barrier coating is applied in the step and, after the cover is welded to the side wall, the side wall is finally machined to a controlled thickness removing all, some or none of the coating.

Burdgick, Steven Sebastian (Schenectady, NY)

2002-01-01

184

Host tissue integration process in abdominal wall defect repair: a comparison of two porcine-derived grafts in a long-term study.  

PubMed

Background: The aim of this study was to compare the host tissue integration process and biomechanical behaviour after implantation of porcine small intestine submucosa (PSIS) and porcine acellular dermal matrix (PADM) grafts in a rat abdominal wall defect model during a long-term follow-up of 360 days. Objectives: Full-thickness abdominal wall defects were created in 40 Sprague-Dawley rats and repaired with either PSIS or PADM grafts. Rats were sacrificed at 14, 30, 90 and 360 days to evaluate the presence of herniation, infection, adhesions and changes in thickness and strength properties of the regenerated tissue at the defect site. Histopathology and immunohistochemistry were performed to evaluate the host tissue integration process assessed by the level of collagen deposition, vascularization and inflammatory host sub-chronic and chronic responses. Results: PADM grafts had greater strength in vitro (p < 0.01). Moreover, the strength of the PADM grafts integrated with the surrounding host tissues was greater than that of the PSIS grafts at 360 days postimplantation (p < 0.05). A stronger integration into the host tissue was observed for the PADM grafts, which showed oriented bands of collagen deposition intermixed with similar newly formed blood vessels compared to that of PSIS grafts after 360 days. The PADM grafts showed slower infiltration of macrophages but developed into a more heavily infiltrated tissue compared to the PSIS grafts (p < 0.05). The level of leukocyte infiltration after implantation was similar in both grafts (p > 0.05). Conclusion: PADM grafts exhibit more delayed but also more effective host integration than PSIS grafts during the 360 days following implantation, supporting the development of more robust abdominal wall strength. PMID:24707915

Liu, Zhengni; Yang, Zhi; Zhou, Zhiyuan; Song, Zhicheng; Wang, Huichun; Yang, JianJun; Tang, Rui; Tan, Qiang; Gu, Yan

2014-07-01

185

Bronchial wall thickness measurement in computed tomography: effect of intravenous contrast agent and reconstruction kernel.  

PubMed

Bronchial wall thickness measurements in computed tomography (CT) has become a useful tool for assessment of the severity of diseaseand the response to treatment in a large number of pulmonary diseases. However, there are only few reports evaluating its dependence on different scan protocols. The effect of intravenous contrast medium has not been analyzed. The aim of this study was to evaluate the influence of intravenous contrast medium application, the contrast phase (arterial and venous) and different reconstruction kernels on bronchial wall measurements of a newly developed algorithm. The bronchial wall thickness was analyzed in 630 bronchial sections of 56 CT examinations with dedicated software (MEVIS Airway Examiner, Fraunhofer MEVIS Bremen, Germany). Application of i.v. contrast agent significantly increased bronchial wall thickness (paired t-test, p<0.001). Comparing arterial and venous phase, bronchial wall thickness was significant higher in the arterial phase (paired t-test, p=0.045). Bronchial wall thickness also increased (ANOVA with Bonferroni correction, p<0.001) when using a softer reconstruction kernel. The absolute differences in bronchial wall thickness were independent of bronchial size and generation. PMID:22673777

Dettmer, S; Entrup, J; Schmidt, M; de Wall, C; Wacker, F; Shin, H

2012-11-01

186

Axisymmetric Wave Transmission Through Wall Thickness Discontinuities in Fluid-Filled Cylindrical Shells.  

National Technical Information Service (NTIS)

The propagation of axisymmetric flexural type waves through wall thickness discontinuities in fluid-filled cylindrical shells is investigated. Dispersion curves for wave behaviour in fluid-filled shells are obtained and the values are used in equations re...

C. R. Fuller

1981-01-01

187

Subcostal transversus abdominis plane phenol injection for abdominal wall cancer pain.  

PubMed

A subcostal transversus abdominis plane (TAP) phenol injection was performed on a patient with refractory cancer pain due a metastatic involvement of the abdominal wall. A diagnostic block with local anesthetic was performed under ultrasound guidance (USG), resulting in a decrease of 80% and 100% in dynamic and static visual analog scale (VAS) for pain, respectively, for 20 hours. A phenol injection was then performed under USG. The patient reported 70% and 100% reduction in the dynamic and static VAS for pain and had a 50% decrease in the opioid requirement that was maintained for 2 months. TAP blocks offer an interesting tool for either diagnosis or therapeutic purpose in chronic pain management. USG provides an optimal approach to soft-tissue lesions where fluoroscopy techniques are not useful. PMID:23560547

Restrepo-Garces, Carlos Eduardo; Asenjo, Juan Francisco; Gomez, Carlos Mario; Jaramillo, Santiago; Acosta, Nathalia; Ramirez, Lizeth Jazmin; Lopera, Luz Maria; Vargas, Juan Felipe

2014-03-01

188

Abdominal wall port site metastasis after robotically staged endometrial carcinoma: A case report  

PubMed Central

INTRODUCTION The incidence of port-site metastasis following robotic-assisted laparoscopic hysterectomy is unknown. PRESENTATION OF CASE We present a case of a 78-year-old female diagnosed with an incidental grade 3 endometrial adenocarcinoma on a final hysterectomy specimen. She subsequently underwent a robotic staging surgery with a gynecologic oncologist where nodal pathology was found to be negative; her final stage was 1B. One year following diagnosis, she developed a recurrence on her abdominal wall at the former port-sites with concomitant vaginal cuff recurrence. DISCUSSION We hypothesize possible modes of metastasis and present limited published data to date on port site metastasis following robotic hysterectomy for endometrial cancer. CONCLUSION This is the second reported case of port-site metastasis following robotic surgery for endometrial cancer.

Nguyen, My-Linh T.; Friedman, Jaclyn; Pradhan, Tana S.; Pua, Tarah L.; Tedjarati, Sean S.

2013-01-01

189

Deletion of Mesenchymal Glucocorticoid Receptor Attenuates Embryonic Lung Development and Abdominal Wall Closure  

PubMed Central

As a member of the nuclear hormone receptor superfamily of ligand-activated transcription factors, the glucocorticoid receptor (GR) is essential for normal embryonic development. To date, the role of mesenchymal glucocorticoid signaling during development has not been fully elucidated. In the present study, we investigated the role of the GR during embryogenesis specifically in mesenchymal tissues. To this aim, we crossed GRflox mice with Dermo1-Cre mice to generate GRDermo1 mice, where the GR gene was deleted within mesenchymal cells. Compared to their wild type littermates, GRDermo1 mice displayed severe pulmonary atelectasis, defects in abdominal wall formation resulting in intestinal herniation, abnormal extracellular matrix synthesis in connective tissues and high postnatal lethality. Lungs of GRDermo1 mice failed to progress from the canalicular to saccular stage, as evidenced by the presence of immature air sacs, thickened interstitial mesenchyme and an underdeveloped vascular network between E17.5 and E18.5. Furthermore, myofibroblasts and vascular smooth muscle cells, although present in normal numbers in GRDermo1 animals, were characterized by significantly reduced elastin synthesis, whilst epithelial lining cells of the immature saccules were poorly differentiated. A marked reduction in normal elastin and collagen deposits were also observed in connective tissues adjacent to the umbilical hernia. This study demonstrates that eliminating the GR in cells of the mesenchymal lineage results in marked effects on interstitial fibroblast function, including a significant decrease in elastin synthesis. This results in lung atelectasis and postnatal lethality, as well as additional and hitherto unrecognized developmental defects in abdominal wall formation. In addition, altered glucocorticoid signaling in the mesenchyme attenuates normal lung epithelial differentiation.

Stoner, Shihani; Tuckermann, Jan; Seibel, Markus; Zhou, Hong

2013-01-01

190

Repair of Abdominal Wall Defects with Biodegradable Laminar Prostheses: Polymeric or Biological?  

PubMed Central

Introduction Biological and synthetic laminar absorbable prostheses are available for the repair of hernia defects in the abdominal wall. They share the important feature of being gradually degraded in the host, resulting in place the formation of a neotissue. This study was designed to assess the host tissue’s incorporation of collagen bioprostheses and a synthetic absorbable prosthesis. Methods Partial defects were created in the abdominal walls of 72 New Zealand rabbits and repaired using collagen bioprostheses Tutomesh® and Strattice® or a synthetic prosthesis Bio-A®. Specimens were collected for light microscopy, collagens gene and protein expression, macrophage response and biomechanical resistance at 14, 30, 90 and 180 days post-implantation. Results Tutomesh® and Bio-A® were gradually infiltrated by the host tissue and almost completely degraded by 180 days post-implantation. In contrast, Strattice® exhibited material encapsulation, no prosthetic degradation and low cell infiltration at earlier timepoints, whereas at later study time, collagen deposition could be observed within the mesh. In the short term, Bio-A® exhibited higher level of collagen 1 and 3 mRNA expression compared with the two other biological prostheses, which exhibited two peaks of higher expression at 14 and 90 days. The expression of collagen III was homogeneous throughout the study and collagen I deposition was more evident in Strattice®. Macrophage response decreased over time in biomeshes. However, in the synthetic mesh remained high and homogeneous until 90 days. The biomechanical analysis demonstrated the progressively increasing tensile strength of all biomaterials. Conclusions The tissue infiltration of laminar absorbable prostheses is affected by the structure and composition of the mesh. The synthetic prosthesis exhibited a distinct pattern of tissue incorporation and a greater macrophage response than did the biological prostheses. Of all of the laminar, absorbable biomaterials that were tested in this study, Strattice® demonstrated the optimal levels of integration and degradation.

Pascual, Gemma; Sotomayor, Sandra; Rodriguez, Marta; Perez-Kohler, Barbara; Bellon, Juan M.

2012-01-01

191

Nitrate Diffusional Releases from the Saltstone Facility, Vault 2, with Respect to Different Concrete Wall Thicknesses  

Microsoft Academic Search

To assist the Saltstone Vault 2 Design Team, an investigation was conducted to evaluate the effectiveness of alternative concrete wall thicknesses in limiting nitrate diffusion away from the planned facility. While the current design calls for 18-inch concrete walls, alternative thicknesses of 12-in, 8-in, and 6-in were evaluated using a simplified 1-D numerical model. To serve as a guide for

2005-01-01

192

Experimental determination of stress-concentration factors in thick-walled cylinders with crossholes and sideholes  

Microsoft Academic Search

In a companion paper1 submitted to ASME, the theoretical determination of stress-concentration factors in thick-walled cylinders was reported.\\u000a The present paper reports the results of experiments conducted to check the predictions of the theory. The configuration is\\u000a a thick-walled cylinder with crossholes or sideholes oriented perpendicular to the bore. Stress concentrations occur at the\\u000a “tee” intersections of the holes with

J. C. Gerdeen; R. E. Smith

1972-01-01

193

Transient increase in wall thickness of the left ventricular apex after stunned myocardium: a case report.  

PubMed

A case of transiently increased wall thickness in the left ventricular apex after stunned myocardium due to severe attack of vasospastic angina is described. "Ace of spades" configuration, documented by left ventriculogram and increased apical wall thickness of the left ventricle, as revealed by two-dimensional echocardiograms returned to normal in 2 months. This transiently increased left ventricular mass may have been due to myocardial edema, which is occasionally seen in the recovery course of active myocarditis. PMID:1533169

Iga, K; Kitaguchi, K; Hori, K; Matumura, T; Gen, H; Tomonaga, G; Tamamura, T

1992-01-01

194

Experimental determination of splitting in axially collapsed thick-walled fibre-reinforced composite frusta  

Microsoft Academic Search

The failure mechanisms of thick-walled circular frusta, made of glassfibre-reinforced composite material, when subjected to axial compression are reported. Depending on wall thickness and the semi-apical angle, a conical shell may fail by four distinct deformation modes: progressive crushing, splitting, mid-length failure and progressive folding.Progressive crushing was found to offer the highest energy-absorption efficiency, the two latter belonging to catastrophic

A. G. Mamalis; D. E. Manolakos; G. A. Demosthenous; M. B. Ioannidis

1997-01-01

195

Periapical radiographs overestimate root canal wall thickness during post space preparation  

Microsoft Academic Search

Souza EM, Bretas RT, Cenci MS, Maia-Filho EM, Bonetti-Filho I. Periapical radiographs overestimate root canal wall thickness during post space preparation. International Endodontic Journal, 41, 658-663, 2008. Aim To evaluate differences between anatomic and radiographic measurements of root canal wall thick- ness (RCWT) after each root canal preparation stage during post placement. Methodology Twenty mandibular premolars with a single canal

E. M. Souza; R. T. Bretas; M. S. Cenci; E. M. Maia-Filho; I. Bonetti-Filho

2008-01-01

196

Clad vent set cup open end (closure weld zone) wall-thickness study  

Microsoft Academic Search

The wall thickness at the open end of Clad Vent Set (CVS) cups is a very important parameter for maintaining control of the fueled CVS closure weld process. Ideally, the wall thickness in the closure weld zone should be constant. The DOP-26 iridium alloy is very difficult to machine; therefore, key dimensional features are established during the two-draw warm-forming operation.

G. B. Ulrich; M. W. Sherrill

1994-01-01

197

Optimization of Part Wall Thicknesses to Reduce Warpage of Injection-Molded Parts Based on The Modified Complex Method  

Microsoft Academic Search

The objective of this work is to minimize warpage of injection-molded parts by deliberately varying each part wall thickness within prescribed dimensional tolerance. The continuous design space of wall thicknesses is explored in search of the optimum wall thickness for given process conditions. The objective function to be minimized is the numeric warpage value, which requires extensive computational time. Once

B. H. Lee; B. H. Kim

1995-01-01

198

Clad vent set cup open end (closure weld zone) wall-thickness study  

SciTech Connect

The wall thickness at the open end of Clad Vent Set (CVS) cups is a very important parameter for maintaining control of the fueled CVS closure weld process. Ideally, the wall thickness in the closure weld zone should be constant. The DOP-26 iridium alloy is very difficult to machine; therefore, key dimensional features are established during the two-draw warm-forming operation. Unfortunately, anisotropy in the forming blanks produces four ears at the open end of each cup. Formation of these ears produces axial and circumferential variations in wall thickness. The cup certification requirement is that the wall thickness in the closure weld zone, defined as the 2.5-mm band at the open end of a cup, measure from 0.63 to 0.73 mm. The wall thickness certification data for the open end of the CVS cups have been statistically evaluated. These data show that the cups recently produced for the Cassini mission have well-controlled open-end wall thicknesses.

Ulrich, G.B.; Sherrill, M.W.

1994-09-01

199

Post-cast EDM method for reducing the thickness of a turbine nozzle wall  

DOEpatents

A post-cast EDM process is used to remove material from the interior surface of a nozzle vane cavity of a turbine. A thin electrode is passed through the cavity between opposite ends of the nozzle vane and displaced along the interior nozzle wall to remove the material along a predetermined path, thus reducing the thickness of the wall between the cavity and the external surface of the nozzle. In another form, an EDM process employing a profile as an electrode is disposed in the cavity and advanced against the wall to remove material from the wall until the final wall thickness is achieved, with the interior wall surface being complementary to the profile surface.

Jones, Raymond Joseph (Duanesburg, NY); Bojappa, Parvangada Ganapathy (Schenectady, NY); Kirkpatrick, Francis Lawrence (Galway, NY); Schotsch, Margaret Jones (Clifton Park, NY); Rajan, Rajiv (Guilderland, NY); Wei, Bin (Mechanicville, NY)

2002-01-01

200

Reconstruction of carotid bifurcation hemodynamics and wall thickness using computational fluid dynamics and MRI  

Microsoft Academic Search

A thorough understanding of the relationship between local hemodynamics and plaque progression has been hindered by an inability to prospectively monitor these factors in vivo in humans. In this study a novel approach for noninvasively recon- structing artery wall thickness and local hemodynamics at the human carotid bifurcation is presented. Three-dimensional (3D) models of the lumen and wall boundaries, from

David A. Steinman; Jonathan B. Thomas; Hanif M. Ladak; Jaques S. Milner; Brian K. Rutt; J. David Spence

2002-01-01

201

Huge desmoid tumor of the anterior abdominal wall mimicking an intraabdominal mass in a postpartum woman: a case report  

PubMed Central

Desmoid tumors are benign neoplasms that most often arise from muscle aponeurosis and have been associated with both trauma and pregnancy. The etiology of desmoids has not been determined. We report the case of anterior abdominal wall desmoid tumor in a female patient with previous history of cesarean section. Preoperative ultrasound and computed tomography demonstrated a large mass mimicking a large hematoma or an intraabdominal mass. The tumor was removed by wide excision with safe margins. The abdominal wall defect was reconstructed with polypropylene mesh. Subsequent histology revealed a desmoid tumor. Desmoid tumors in females are often associated with pregnancy or occur post-partum. The reasons behind this association are unclear. The most common sites are in the abdominal muscles.

Trigui, Khaled; Bouassida, Mahdi; Kilani, Houda; Mighri, Mohamed Mongi; Sassi, Selim; Chebbi, Fathi; Touinsi, Hassen; Sassi, Sadok

2013-01-01

202

Huge desmoid tumor of the anterior abdominal wall mimicking an intraabdominal mass in a postpartum woman: a case report.  

PubMed

Desmoid tumors are benign neoplasms that most often arise from muscle aponeurosis and have been associated with both trauma and pregnancy. The etiology of desmoids has not been determined. We report the case of anterior abdominal wall desmoid tumor in a female patient with previous history of cesarean section. Preoperative ultrasound and computed tomography demonstrated a large mass mimicking a large hematoma or an intraabdominal mass. The tumor was removed by wide excision with safe margins. The abdominal wall defect was reconstructed with polypropylene mesh. Subsequent histology revealed a desmoid tumor. Desmoid tumors in females are often associated with pregnancy or occur post-partum. The reasons behind this association are unclear. The most common sites are in the abdominal muscles. PMID:23593530

Trigui, Khaled; Bouassida, Mahdi; Kilani, Houda; Mighri, Mohamed Mongi; Sassi, Selim; Chebbi, Fathi; Touinsi, Hassen; Sassi, Sadok

2013-01-01

203

Systematic review and meta-analysis of the effectiveness of antibiotic prophylaxis in prevention of wound infection after mesh repair of abdominal wall hernia  

Microsoft Academic Search

Background: The aim was to determine whether systemic antibiotic prophylaxis prevented wound infection after of abdominal wall hernia with mesh. Method: This was a systematic review of the available literature identified from multiple database using the terms 'hernia' and 'antibiotic prophylaxis'. Randomized placebo-controlled trials of antibiotic prophylaxis in abdominal wall mesh hernia repair with explicitly defined wound infection criteria and

T. J. Aufenacker; M. J. W. Koelemay; D. J. Gouma; M. P. Simons

2006-01-01

204

[On the mechanism of action of cryomassage of the abdominal wall in the patients presenting with gastroduodenal pathology].  

PubMed

The mechanism of action of cryomassage of the abdominal wall in the patients presenting with gastroduodenal pathology is considered. The authors suppose that the positive effect of cryotherapy is underlain by normalization of microcirculation in the digestive organs and the resulting improvement of energy and plastic support of intracellular processes, e.g. phosphorylation. PMID:24437209

FilimonovR, R M; Stiazhkina, E M; Filimonova, T R

2013-01-01

205

Two-stage free latissimus dorsi flap: a safe strategy for reconstruction of large defects of the abdominal wall.  

PubMed

We report a case of full abdominal wall reconstruction after resection of a dermatofibrosarcoma protuberans. The treatment comprised wide resection with a 5 cm peripheral margin and deep resection to a disease-free anatomical structure. The reconstruction was done in two-stages with a free latissimus dorsi flap. PMID:23547533

Fejjal, Nawfal; Hafidi, Jawad; Belmir, Redouane; El Mazouz, Samir; Abbassi, Abdellah; Lahlou, Khalid; Gharib, Noureddine

2013-06-01

206

CLASSICAL AREAS OF PHENOMENOLOGY: Influence of the abdominal wall on the nonlinear propagation of focused therapeutic ultrasound  

Microsoft Academic Search

This article theoretically studies the influence of inhomogeneous abdominal walls on focused therapeutic ultrasound based on the phase screen model. An inhomogeneous tissue is considered as a combination of a homogeneous medium and a phase aberration screen. Variations of acoustic parameters such as peak positive pressure, peak negative pressure, and acoustic intensity are discussed with respect to the phase screen

Zhen-Bo Liu; Ting-Bo Fan; Dong Zhang; Xiu-Fen Gong

2009-01-01

207

Performance Evaluation of Several Types of Pulsed Eddy Current Probes for Detecting Wall Thickness Reduction  

NASA Astrophysics Data System (ADS)

In this paper, four different types of pulsed eddy current (PEC) probe are designed and their performance of detecting wall thickness reduction is compared. By using the backward difference method in time and the finite element method in space, PEC signals from various thickness and materials are numerically calculated and three features of the signal are selected. Since PEC signals and features are obtained by various types and sizes of probe, the comparison is made through the normalized features which reflect the sensitivity of the feature to thickness reduction. The normalized features indicate that the shielded reflection probe provides the best sensitivity to wall thickness reduction for all three signal features. Results show that the best sensitivity to thickness reduction is achieved by the peak value, but also suggest that the time to peak can be a good candidate because of its linear relationship with the thickness variation.

Shin, Young-Kil; Choi, Dong-Myung; Jung, Hee-Sung; Um, Tae-Gun

2010-02-01

208

[Morphology of tissue reactions around implants after combined surgical repair of the abdominal wall].  

PubMed

Tissue reactions to titanium-nickelide and polypropylen and caprone implants used in surgical treatment of anterior aldomen wall hernias were studied in experiment. Digital density of leukocytes, fibroblasts, vessels, thickness of the capsule were studied. Pronounced inflammatory reaction was observed on day 3 which attenuated on day 14 in case of titanium nickelide and on day 30-60 in case of polypropylene and caprone. Fibroplastic processes start in the first group after 7 days while in the second group only after 30 days of the experiment. Thickness of the capsule around titanium-nickelide was 2-3 times less than around polypropylene and caprone. Thus, titanium-nickelide material is biologically more inert than caprone and polypropylen which are widely used in surgery of hernias. PMID:15154379

Vostrikov, O V; Zotov, V A; Nikitenko, E V

2004-01-01

209

Giant pseudocyst of the anterior abdominal wall following mesh repair of incisional hernia: a rare complication managed laparoscopically.  

PubMed

Giant pseudocyst formation of the anterior abdominal wall, following on-lay polypropylene mesh repair for incisional hernia is an under reported complication. We report an unusual case of a 56-year-old female who underwent a polypropylene mesh repair of incisional hernia 2 years back. Subsequently she developed a giant pseudocyst of the anterior abdominal wall, which was occupying the whole of the abdomen from the xiphisternum to the pubic bone, and over both the flanks. Over a period of one year, the cyst had defied multiple attempts at aspiration. The patient underwent a laparoscopic drainage of the collection with piecemeal excision of the entire cyst wall. Histopathology of the cyst wall revealed necrotic material with intervening areas of hemorrhage. No epithelial lining was seen. There has been no recurrence in the two years of follow-up. Conclusion: giant pseudocyst of the anterior abdominal wall is a rare complication following mesh repair of an incisional hernia. Such pseudocysts can be managed successfully by laparoscopic procedures. PMID:16136392

Mehrotra, Prateek K; Ramachandran, C S; Goel, Deep; Arora, Vijay

2006-04-01

210

3-D segmentation and quantitative analysis of inner and outer walls of thrombotic abdominal aortic aneurysms  

NASA Astrophysics Data System (ADS)

An abdominal aortic aneurysm (AAA) is an area of a localized widening of the abdominal aorta, with a frequent presence of thrombus. A ruptured aneurysm can cause death due to severe internal bleeding. AAA thrombus segmentation and quantitative analysis are of paramount importance for diagnosis, risk assessment, and determination of treatment options. Until now, only a small number of methods for thrombus segmentation and analysis have been presented in the literature, either requiring substantial user interaction or exhibiting insufficient performance. We report a novel method offering minimal user interaction and high accuracy. Our thrombus segmentation method is composed of an initial automated luminal surface segmentation, followed by a cost function-based optimal segmentation of the inner and outer surfaces of the aortic wall. The approach utilizes the power and flexibility of the optimal triangle mesh-based 3-D graph search method, in which cost functions for thrombus inner and outer surfaces are based on gradient magnitudes. Sometimes local failures caused by image ambiguity occur, in which case several control points are used to guide the computer segmentation without the need to trace borders manually. Our method was tested in 9 MDCT image datasets (951 image slices). With the exception of a case in which the thrombus was highly eccentric, visually acceptable aortic lumen and thrombus segmentation results were achieved. No user interaction was used in 3 out of 8 datasets, and 7.80 +/- 2.71 mouse clicks per case / 0.083 +/- 0.035 mouse clicks per image slice were required in the remaining 5 datasets.

Lee, Kyungmoo; Yin, Yin; Wahle, Andreas; Olszewski, Mark E.; Sonka, Milan

2008-04-01

211

Development of Eddy Current Probe for Thick-Walled Plates and Quantitative Evaluation of Cracks  

NASA Astrophysics Data System (ADS)

This paper demonstrates the crack detection of thick-walled non-magnetic metal plates by eddy current testing, which used to be difficult because of the skin effect generally. For the purpose, this paper proposes a novel eddy current testing probe for cracks in thick-walled plates and evaluates the capability of the present probe. The probe was designed, based on the numerical computation using 3D fast eddy current code. The advantages of the present probe are strong eddy current on the back of specimens and small decay of eddy current in the thickness direction. Through experiments, we confirmed that this probe can detect the back artificial defect on INCONEL718 specimen with thickness of 7.0mm and 304 Stainless steel specimen with thickness of 8.0mm.

Takagi, T.; Uchimoto, T.; Sato, K.; Huang, H.

2003-03-01

212

Colonic wall thickness using level sets for CT virtual colonoscopy visual assessment and polyp detection  

NASA Astrophysics Data System (ADS)

The detection of polyps in virtual colonoscopy is an active area of research. One of the critical elements in detecting cancerous polyps using virtual colonoscopy, especially in conjunction with computer-aided detection, is the accurate segmentation of the colon wall. The large CT attenuation difference between the lumen and inner, mucosal layer of the colon wall makes the segmentation of the lumen easily performed by traditional threshold segmentation techniques. However, determining the location of the colon outer wall is often difficult due to the low contrast difference between the colon wall's outer serosal layer and the fat surrounding the colon. We have developed an automatic, level set based method to determine from a CT colonography scan the location of the colon inner boundary and the colon outer wall boundary. From the location of the inner and outer colon wall boundaries, the wall thickness throughout the colon can be computed. Color mapping of the wall thickness on the colon surface allows for easy visual determination of potential regions of interest. Since the colon wall tends to be thicker at polyp locations, potential polyps also can be detected automatically at sites of increased colon wall thickness. This method was validated on several CT colonography scans containing optical colonoscopy-proven polyps. The method accurately determined thicker colonic wall regions in areas where polyps are present in the ground truth datasets and detected the polyps at a false positive rate between 44.4% and 82.8% lower than a state-of-the-art curvature-based method for initial polyp detection.

Van Uitert, Robert L.; Summers, Ronald M.

2007-03-01

213

Airway wall thickness assessment: a new functionality in virtual bronchoscopy investigation  

NASA Astrophysics Data System (ADS)

While classic virtual bronchoscopy offers visualization facilities for investigating the shape of the inner airway wall surface, it provides no information regarding the local thickness of the wall. Such information may be crucial for evaluating the severity of remodeling of the bronchial wall in asthma and to guide bronchial biopsies for staging of lung cancers. This paper develops a new functionality with the virtual bronchoscopy, allowing to estimate and map the information of the bronchus wall thickness on the lumen wall surface, and to display it as coded colors during endoluminal navigation. The local bronchus wall thickness estimation relies on a new automated 3D segmentation approach using strong 3D morphological filtering and model-fitting. Such an approach reconstructs the inner/outer airway wall surfaces from multi-detector CT data as follows. First, the airway lumen is segmented and its surface geometry reconstructed using either a restricted Delaunay or a Marching Cubes based triangulation approach. The lumen mesh is then locally deformed in the surface normal direction under specific force constraints which stabilize the model evolution at the level of the outer bronchus wall surface. The developed segmentation approach was validated with respect to both 3D mathematicallysimulated image phantoms of bronchus-vessel subdivisions and to state-of-the-art cross-section area estimation techniques when applied to clinical data. The investigation in virtual bronchoscopy mode is further enhanced by encoding the local wall thickness at each vertex of the lumen surface mesh and displaying it during navigation, according to a specific color map.

Saragaglia, A.; Fetita, C.; Brillet, P. Y.; Pr"teux, F.; Grenier, P. A.

2007-03-01

214

Study of Intrusion Bending for Steel Tubes with Thin Wall Thickness  

NASA Astrophysics Data System (ADS)

In regard to light-weight structural members for automobiles, attention to hydroforming has been increasing. Intrusion-bending method is well suited to the preliminary bending of hydroformed structural members of automobiles, because straight tubes can be bent into three-dimensional forms by this new method. However, in the case of tubes with a thin wall thickness, wrinkling remains a problem. In this report, application of intrusion bending method to tubes with extremely low ratios of wall thickness to outer diameter (from 1.2 to 1.9%), and whose steel grades are SSPDX, SAFC440R, and SAFC590T was investigated. A summary of this study is as follows. Effects of steel grades and wall thickness ratios on wrinkle formation, eccentricity, and ovality are studied. Relationships between wrinkle generation and gyro movement are investigated.

Naoi, Hisashi; Kitakami, Naoki; Mizumura, Masaaki; Kuriyama, Yukihisa

2008-06-01

215

Composite prostheses used to repair abdominal wall defects: physical or chemical adhesion barriers?  

PubMed

In a composite prosthesis, the component placed at the peritoneal interface takes the form of a physical or chemical barrier. In this experimental study performed on the white New Zealand rabbit, several composites were examined to establish the effectiveness of these barriers at impeding adhesion formation. The biomaterials tested were two polypropylene prostheses (PP) with the physical barriers of expanded polytetrafluoroethylene or polyurethane (PP + ePTFE and PP + PU) and two prostheses (one polyester and the other PP) with the absorbable chemical barriers of polyethylene glycol/glycerol and hyaluronate, respectively (PO + gl and PP + hy). The composites were used to repair 7 x 5 cm defects created in the abdominal wall of the animals by placing the implant in contact with the visceral peritoneum and the subcutaneous tissue and fixing it to recipient tissue by 4/0 polypropylene running suture. Fourteen days after surgery the animals were sacrificed and specimens were taken for light microscopy and scanning electron microscopy. Adhesions developing at the prosthesis/visceral peritoneal interface were quantified. All the prostheses induced optimal mesothelialization. Composites with physical barriers behaved similarly in terms of provoking adhesions. However, the prostheses with chemical barriers differed in their effectiveness at preventing adhesions. Overall, the best results were obtained with the PP + PU composite. PMID:15977312

Bellón, J M; Serrano, N; Rodríguez, M; García-Honduvilla, N; Pascual, G; Buján, J

2005-08-01

216

Histological response to and immunogenicity of different material patches implanted in rabbit abdominal walls.  

PubMed

The high failure rate of traditional procedures of repairing pelvic organ prolapse by using sutures pushes multiple transvaginal mesh delivery systems into the marketplace; however, these are currently without optimal clinical results. We observed the short-term histological changes and the effects of Th1/Th2 cytokines after the implantation in rabbit abdominal walls of five materials, i.e., porcine urinary bladder matrix (UBM), cross-linked UBM, polypropylene mesh, composite cross-linked UBM, and composite UBM, and explored the feasibility of their application to pelvic reconstructive surgery. Grafts were harvested at 1, 2, 4, 8, and 12 weeks after surgery and were processed for histology in order to evaluate the host inflammatory response and the degree of tissue incorporation. Additionally, graft site cytokine levels were determined by reverse transcriptase polymerase chain reaction. The results demonstrate that the two composite groups were associated with an erosion response, whereas the other groups induced a milder response than the composite groups. The Th1/Th2 cytokine mRNA expression levels of the cross-linked UBM group at each time point were similar to that of the sham group, whereas the other groups elicited a more variable expression. The cross-linked UBM showed slow degradation, mild inflammatory response, and low immunogenicity. This suggests that cross-linked UBM is a better material of choice for pelvic reconstructive surgery. PMID:23633460

Fan, Xuemei; Xu, Senlin; Wang, Yanzhou; Li, Shengping; Wang, Yu; Xu, Huicheng

2013-08-01

217

A Comparison of Vaginal Pressures and Abdominal Muscle Thickness According to Childbirth Delivery Method during the Valsalva Maneuver  

PubMed Central

[Purpose] The purpose of this study was to compare the effect of childbirth delivery method on vaginal pressure and abdominal thickness during the Valsalva maneuver (VAL). [Subjects] Thirty healthy female volunteers (26–39?years of age) were selected for this research. Their delivery histories were: nulliparous 10, vaginal delivery 10, and Cesarean delivery 10. None of the participants had a history of incontinence. [Methods] In the crook-lying position, a perineometer probe was inserted into the vagina and the transducer was placed transversely on the right side of the body during the Valsalva maneuver. [Results] There were significant differences in the thickness of the transverses abdominis (TrA) between in all the groups rest and the Valsalva maneuver, and there were significant differences in the internus oblique (IO) in the nulliparous group. During the Valsalva maneuver, there were significant differences in the TrA between the nulliparous group and the vaginal delivery group, and there were significant differences in the IO between the nulliparous delivery group and the vaginal delivery group, and between the nulliparous group and the Cesarean section group. Delivery history changed vaginal pressure, and there were significant differences between the nulliparous group and the vaginal delivery group, and between the nulliparous group and the Cesarean delivery group. [Conclusion] Pregnancy and delivery method may affect pelvic floor and abdominal muscles during the Valsalva maneuver.

Kim, Haroo; Kak, Hwang-Bo; Kim, Boin

2014-01-01

218

A Comparison of Vaginal Pressures and Abdominal Muscle Thickness According to Childbirth Delivery Method during the Valsalva Maneuver.  

PubMed

[Purpose] The purpose of this study was to compare the effect of childbirth delivery method on vaginal pressure and abdominal thickness during the Valsalva maneuver (VAL). [Subjects] Thirty healthy female volunteers (26-39?years of age) were selected for this research. Their delivery histories were: nulliparous 10, vaginal delivery 10, and Cesarean delivery 10. None of the participants had a history of incontinence. [Methods] In the crook-lying position, a perineometer probe was inserted into the vagina and the transducer was placed transversely on the right side of the body during the Valsalva maneuver. [Results] There were significant differences in the thickness of the transverses abdominis (TrA) between in all the groups rest and the Valsalva maneuver, and there were significant differences in the internus oblique (IO) in the nulliparous group. During the Valsalva maneuver, there were significant differences in the TrA between the nulliparous group and the vaginal delivery group, and there were significant differences in the IO between the nulliparous delivery group and the vaginal delivery group, and between the nulliparous group and the Cesarean section group. Delivery history changed vaginal pressure, and there were significant differences between the nulliparous group and the vaginal delivery group, and between the nulliparous group and the Cesarean delivery group. [Conclusion] Pregnancy and delivery method may affect pelvic floor and abdominal muscles during the Valsalva maneuver. PMID:24707104

Kim, Haroo; Kak, Hwang-Bo; Kim, Boin

2014-03-01

219

General tube law for collapsible thin and thick-wall tubes.  

PubMed

Modeling the complex deformations of cylindrical tubes under external pressure is of interest in engineering and physiological applications. The highly non-linear post-buckling behavior of cross-section of the tube during collapse attracted researchers for years. Major efforts were concentrated on studying the behavior of thin-wall tubes. Unfortunately, the knowledge on post-buckling of thick-wall tubes is still incomplete, although many experimental and several theoretical studies have been performed. In this study we systematically studied the effect of the wall thickness on post-buckling behavior of the tube. For this purpose, we utilized a computational model for evaluation of the real geometry of the deformed cross-sectional area due to negative transmural (internal minus external) pressure. We also developed an experimental method to validate the computational results. Based on the computed cross-sections of tubes with different wall thicknesses, we developed a general tube law that accounts for thin or thick wall tubes and fits the numerical data of computed cross-sectional areas versus transmural pressures. PMID:24837222

Kozlovsky, Pavel; Zaretsky, Uri; Jaffa, Ariel J; Elad, David

2014-07-18

220

An Elastomeric Patch Electrospun from a Blended Solution of Dermal Extracellular Matrix and Biodegradable Polyurethane for Rat Abdominal Wall Repair  

PubMed Central

A biodegradable elastomeric scaffold was created by electrospinning a mixed solution of poly(ester urethane)urea (PEUU) and porcine dermal extracellular matrix (dECM) digest, with PEUU included to provide elasticity, flexibility, and mechanical support and dECM used to enhance bioactivity and biocompatibility. Micrographs and differential scanning calorimetry demonstrated partial miscibility between PEUU and dECM. With greater dECM content, scaffolds were found to possess lower breaking strains and suture retention strength, although initial modulus was greater with higher dECM concentrations. The hybrid scaffolds containing 0% to 50% dECM had tensile strengths of 5 to 7?MPa, breaking strains of 138% to 611%, initial moduli of 3 to 11 Mpa, and suture retention strengths of 35 to 59?MPa. When hydrated, scaffolds were found to contract markedly with 50% dECM content. When used in a rat full-thickness abdominal wall replacement model, no herniation, infection, or tissue adhesion was observed after 4 and 8 weeks with a scaffold containing 25% dECM or a control 100% PEUU scaffold. Scaffolds incorporating dECM were significantly thicker at the time of explant, with greater numbers of associated smooth muscle actin–positive staining cells than in the control, but minimal cellular infiltration and remodeling of the scaffold were detected regardless of dECM addition. The processing of dECM and PEUU from a mixed solution thus provided a scaffold with evidence of better bioactivity and with mechanical properties not achievable with digested dECM alone.

Hong, Yi; Takanari, Keisuke; Amoroso, Nicholas J.; Hashizume, Ryotaro; Brennan-Pierce, Ellen P.; Freund, John M.; Badylak, Stephen F.

2012-01-01

221

Reconstruction of Abdominal Wall of a Chronically Infected Postoperative Wound with a Rectus Abdominis Myofascial Splitting Flap  

PubMed Central

Background If a chronically infected abdominal wound develops, complications such as peritonitis and an abdominal wall defect could occur. This could prolong the patient's hospital stay and increase the possibility of re-operation or another infection as well. For this reason, a solution for infection control is necessary. In this study, surgery using a rectus abdominis muscle myofascial splitting flap was performed on an abdominal wall defect. Methods From 2009 to 2012, 5 patients who underwent surgery due to ovarian rupture, cesarean section, or uterine myoma were chosen. In each case, during the first week after operation, the wound showed signs of infection. Surgery was chosen because the wounds did not resolve with dressing. Debridement was performed along the previous operation wound and dissection of the skin was performed to separate the skin and subcutaneous tissue from the attenuated rectus muscle and Scarpa's fascial layers. Once the anterior rectus sheath and muscle were adequately mobilized, the fascia and muscle flap were advanced medially so that the skin defect could be covered for reconstruction. Results Upon 3-week follow-up after a rectus abdominis myofascial splitting flap operation, no major complication occurred. In addition, all of the patients showed satisfaction in terms of function and esthetics at 3 to 6 months post-surgery. Conclusions Using a rectus abdominis myofascial splitting flap has many esthetic and functional benefits over previous methods of abdominal defect treatment, and notably, it enabled infection control by reconstruction using muscle.

Bae, Sung Kyu; Kang, Seok Joo; Kim, Jin Woo; Kim, Young Hwan

2013-01-01

222

Patient-specific models of wall stress in abdominal aortic aneurysm: a comparison between MR and CT  

NASA Astrophysics Data System (ADS)

Finite element method based patient-specific wall stress in abdominal aortic aneurysm (AAA) may provide a more accurate rupture risk predictor than the currently used maximum transverse diameter. In this study, we have investigated the sensitivity of the wall stress in AAA with respect to geometrical variations. We have acquired MR and CT images for four patients with AAA. Three individual users have delineated the AAA vessel wall contours on the image slices. These contours were used to generate synthetic feature images for a deformable model based segmentation method. We investigated the reproducibility and the influence of the user variability on the wall stress. For sufficiently smooth models of the AAA wall, the peak wall stress is reproducible for three out of the four AAA geometries. The 0.99 percentiles of the wall stress show excellent reproducibility for all four AAAs. The variations induced by user variability are larger than the errors caused by the segmentation variability. The influence of the user variability appears to be similar for MR and CT. We conclude that the peak wall stress in AAA is sensitive to small geometrical variations. To increase reproducibility it appears to be best not to allow too much geometrical detail in the simulations. This could be achieved either by using a sufficiently smooth geometry representation or by using a more robust statistical parameter derived from the wall stress distribution.

de Putter, Sander; Breeuwer, Marcel; van de Vosse, Frans N.; Kose, Ursula; Gerritsen, Frans A.

2006-03-01

223

Use of a pre-expanded "propeller" deep inferior epigastric perforator (DIEP) flap for a large abdominal wall defect.  

PubMed

Large abdominal wall soft tissue defects are traditionally reconstructed using loco-regional flaps and/or tissue expanders. Pedicled perforator flaps offer similar tissue coverage with minimal donor site morbidity and do not require microsurgical skills. The deep inferior epigastric perforator (DIEP) flap has become increasingly popular for breast reconstruction and offers abundant soft tissue while permitting primary donor site closure. To minimize operative sessions, recovery time, donor site morbidity, and avoid microsurgery, we combined tissue expansion with a "propeller" flap design and report this first case of a pre-expanded pedicled perforator flap based on the DIEP to address a large abdominal wall defect due to a burn injury. PMID:23031631

Cheng, Angela; Saint-Cyr, Michel

2013-06-01

224

Evaluation of a Porcine Dermal Collagen (Permacol) Implant for Abdominal Wall Reconstruction in a Pediatric Multitrauma Patient  

PubMed Central

The presence of a contaminated surgical field in abdominal wall defects caused by trauma presents a challenge for surgeons. Both primary suture and synthetic meshes are strongly discouraged as surgical treatments in such cases. We describe the use of a porcine dermal collagen (Permacol) implant in an eight-year-old patient with multiple injuries. Three months after discharge, the child remains well with good cosmetic results. He is free of pain and has returned to full activity levels with complete wound closure and without any evidence of residual hernia. In conclusion, our experience indicates that the use of Permacol can be considered an efficient technique for reconstructing an infected abdominal wall defect of a pediatric multitrauma patient.

Mnouskin, Youri; Verdiger Kurzbart, Edna; Yoffe, Boris

2014-01-01

225

An exact solution for a thick domain wall in general relativity  

NASA Technical Reports Server (NTRS)

An exact solution of the Einstein equations for a static, planar domain wall with finite thickness is presented. At infinity, density and pressure vanish and the space-time tends to the Minkowski vacuum on one side of the wall and to the Taub vacuum on the other side. A surprising feature of this solution is that the density and pressure distribution are symmetric about the central plane of the wall whereas the space-time metric and therefore also the gravitational field experienced by a test particle is asymmetric.

Goetz, Guenter; Noetzold, Dirk

1989-01-01

226

Successful Treatment of Mesenteric Varices After Living Donor Liver Transplantation with Retrograde Transvenous Obliteration Via an Abdominal Wall Vein  

SciTech Connect

Balloon-occluded retrograde transvenous obliteration is an established treatment for gastric varices; it has been used more rarely to treat mesenteric varices. We report a 12-year-old girl who had received a living donor liver transplant and suffered melena due to ruptured mesenteric varices. We addressed treatment of the mesenteric varices by retrograde transvenous obliteration of an abdominal wall collateral vein detected by superior mesenteric arteriography.

Ikeda, Osamu, E-mail: osamu-3643ik@do9.enjoy.ne.jp; Tamura, Yoshitaka; Nakasone, Yutaka; Yamashita, Yasuyuki [Kumamoto University Graduate School of Medical and Pharmaceutical Sciences, Department of Diagnostic Radiology (Japan); Okajima, Hideaki; Asonuma, Katsuhiro; Inomata, Yukihiro [Kumamoto University Graduate School of Medical and Pharmaceutical Sciences, Department of Transplantation and Pediatric Surgery (Japan)

2010-06-15

227

Desmoid Tumors of the Anterior Abdominal Wall: Results from a Monocentric Surgical Experience and Review of the Literature  

Microsoft Academic Search

Background  Desmoid tumor, also known as aggressive fibromatosis, is a rare soft tissue tumor. For those cases localized in the anterior\\u000a abdominal wall, radical resection and reconstruction with a mesh is indicated. Because the rarity of the disease, randomized\\u000a trials are lacking, but in reported retrospective series, it is clear that although it is considered a benign lesion, local\\u000a recurrence is

Emilio Bertani; Antonio Chiappa; Alessandro Testori; Giovanni Mazzarol; Roberto Biffi; Stefano Martella; Ugo Pace; Javier Soteldo; Paolo Della Vigna; Rosalba Lembo; Bruno Andreoni

2009-01-01

228

The venous anatomy of the abdominal wall for Deep Inferior Epigastric Artery (DIEP) flaps in breast reconstruction  

PubMed Central

Background Despite improving outcomes, venous problems in the harvest of deep inferior epigastric artery perforator (DIEP) flaps remain the more common vascular complications. However, it is apparent that the venous anatomy of the anterior abdominal wall has not been described to the same extent as the arterial anatomy. Cadaveric dissection studies of venous anatomy frequently lack the detail of their arterial counterparts. Venous valves complicate retrograde injection, resulting in poor quality studies with limited anatomical information. Methods The current manuscript comprises a review of the literature, highlighting key features of the anatomy of the venous drainage of the abdominal wall integument, with particular pertinence to DIEP flaps. Both cadaveric and clinical studies are included in this review. Our own cadaveric and in-vivo studies were undertaken and included in detail in this manuscript, with the cadaveric component utilizing direct catheter venography and the in-vivo studies were undertaken using preoperative computed tomographic angiography (CTA), mapping in-vivo venous flow. Results Several key features of the venous anatomy of the abdominal wall render it different to other regions, and are of particular importance to DIEP flap transfer. Conclusions The cause of venous compromise is multi-factorial, with perforator diameter, midline crossover, and deep-superficial venous communications all important. Venous cadaveric studies as well as clinical CTA preoperatively can identify these anomalies.

Ashton, Mark W

2012-01-01

229

Magnet Fall inside a Conductive Pipe: Motion and the Role of the Pipe Wall Thickness  

ERIC Educational Resources Information Center

Theoretical models and experimental results are presented for the retarded fall of a strong magnet inside a vertical conductive non-magnetic tube. Predictions and experimental results are in good agreement modelling the magnet as a simple magnetic dipole. The effect of varying the pipe wall thickness on the retarding magnetic drag is studied for…

Donoso, G.; Ladera, C. L.; Martin, P.

2009-01-01

230

Optimum material distributions for prescribed apparent fracture toughness in thick-walled FGM circular pipes  

Microsoft Academic Search

This study treats the inverse problem of evaluating optimum material distributions intending to realize prescribed apparent fracture toughness in thick-walled functionally graded material (FGM) circular pipes. The incompatible eigenstrain induced in the pipes after cooling from the sintering temperature due to the nonhomogeneous coefficient of thermal expansion is taken into consideration. An approximation method of finding stress intensity factors for

A. M. Afsar; H. Sekine

2001-01-01

231

Strength of thick-walled vessels of brittle materials under external pressure  

Microsoft Academic Search

In modern technology use is made of thick-walled vessels of brittle materials such as concrete which are subjected to significant internal pressures. As a result of the poor resistance of brittle materials to tension, in the installation of such vessels those zones of the material in which tensile stresses from service loads are expected are subjected to preliminary strain (compression)

L. K. Luksha

1977-01-01

232

Wall-Thickness Dependence of Cooling-Induced Deformation of Polystyrene Spherical Shells  

SciTech Connect

Experiments on the wall-thickness dependence of the cooling-induced deformation (CID) of polystyrene (PS) spherical shells were carried out. For the experiments, the PS shells were fabricated by the density-matched emulsion method using the hand-shaken microencapsulation technique. The number-averaged and weight-averaged molecular weights of the PS were M{sub n} 1.1 x 10{sup 5} and M{sub w} = 4.0 x 10{sup 5}, respectively. The diameter of the PS shells was {approx}400-550 {mu}m. To investigate the wall-thickness dependence of the CID, the wall thickness of the PS shells was varied between 5 and 60 {mu}m. In the experiments, the PS shells were cooled by using liquid nitrogen, and their images were captured at 0 and -190 deg. C. For the investigation of the CID, two shapes of each shell that were measured at 0 and -190 deg. C were compared. The thinner PS shells showed larger CID. The maximum deformation was almost 1% of the outer radius when the shell aspect ratio (outer radius)/(wall thickness) was higher than 20. The repeatability of the CID was studied, and the results implied that residual stress in the PS shells had an influence on the CID.

Endo, T.; Kobayashi, N.; Goto, K.; Yasuda, M.; Fujima, Y. [Nagoya University (Japan)

2003-05-15

233

Optimal Design of Dynamically Loaded Rigid-Plastic Structures. Application: Thick-Walled Concrete Tube  

Microsoft Academic Search

A general approximate method for the optimal design of perfectly plastic inhomogeneous structures exposed to dynamic pressure is presented. The solution is based on the kinematical approach and on simple rigid-plastic idealization and leads to mathematical programming. The application of the method is illustrated by the optimal design of thick-walled concrete tubes reinforced on their exterior surface by steel wires.

M. Heinloo; S. Kaliszky

1981-01-01

234

Asymmetric bifurcations of thick-walled circular cylindrical elastic tubes under axial loading and external pressure  

Microsoft Academic Search

In this paper, we consider bifurcation from a circular cylindrical deformed configuration of a thick-walled circular cylindrical tube of incompressible isotropic elastic material subject to combined axial loading and external pressure. In particular, we examine both axisymmetric and asymmetric modes of bifurcation. The analysis is based on the three-dimensional incremental equilibrium equations, which are derived and then solved numerically for

Y. Zhu; X. Y. Luo; R. W. Ogden

2008-01-01

235

Ultrasonographic Evaluation of Bowel Wall Thickness and Intramural Blood Flow in Ulcerative Colitis  

PubMed Central

Aim. This study aimed at assessing Doppler ultrasonographic findings of gut wall vessels and thickness in active and quiescent ulcerative colitis. Methods. Fifty patients with ulcerative colitis were studied using transabdominal grayscale and Doppler sonography of sigmoid, distal and middle parts of descending colon in different stages of the disease. Thickness of colon wall in the most involved site, number of color signals in each box, resistive index (RI), and pulsatility index (PI) were evaluated. Results. The median thickness of the colon wall in the most involved sites was 4.3?mm in acute phase and 4.4?mm in the inactive phase (P = 0.47). The median number of the color signals in the active phase at the most involved site, distal part of descending colon and sigmoid was higher than that of the color signals in the inactive phase (P = 0.0001). In the most involved site, the PI and RI were undetectable in the inactive phase. The median PI was 1.4 in the mild phase, 1.3 in the moderate phase, and 1.1 in the severe phase (P = 0.002). Conclusion. In contrast to the colon wall thickness, increased intramural blood flow reflected the clinical severity in ulcerative colitis patients.

Bavil, Abolhassan Shakeri; Somi, Mohommad Hossein; Nemati, Masoud; Nadergoli, Batool Seyfi; Ghabili, Kamyar; Mirnour, Reshad; Ashrafi, Hamideh

2012-01-01

236

Room temperature synthesis of indium tin oxide nanotubes with high precision wall thickness by electroless deposition  

PubMed Central

Summary Conductive nanotubes consisting of indium tin oxide (ITO) were fabricated by electroless deposition using ion track etched polycarbonate templates. To produce nanotubes (NTs) with thin walls and small surface roughness, the tubes were generated by a multi-step procedure under aqueous conditions. The approach reported below yields open end nanotubes with well defined outer diameter and wall thickness. In the past, zinc oxide films were mostly preferred and were synthesized using electroless deposition based on aqueous solutions. All these methods previously developed, are not adaptable in the case of ITO nanotubes, even with modifications. In the present work, therefore, we investigated the necessary conditions for the growth of ITO-NTs to achieve a wall thickness of around 10 nm. In addition, the effects of pH and reductive concentrations for the formation of ITO-NTs are also discussed.

Ionescu, Emanuel; Fu, Ganhua; Ensinger, Wolfgang

2011-01-01

237

Abdominal hollowing and lateral abdominal wall muscles' activity in both healthy men & women: An ultrasonic assessment in supine and standing positions.  

PubMed

The objective of this study was to investigate the effects of Abdominal Hollowing (AH) maneuver on External Oblique (EO), Internal Oblique (IO) and Transversus Abdominis (TrA) muscles in both healthy men and women during the two postures of supine and upright standing. The study was conducted on 43 asymptomatic volunteers (22 males and 21 females) aged 19-44 (27.8±6.4) years. Rehabilitative Ultrasonic Imaging (RUSI) was simultaneously performed to measure muscle thickness in both rest and during AH maneuvers while activation of the TrA during AH was controlled by Pressure Biofeedback (PBF) device. Mixed-model ANOVA with repeated measures design, and Pearson correlation tests were used to analyze the data. Muscle thickness of all muscles was significantly higher for male subjects (F>6.2, p<0.017). The interaction effect of gender and muscle status was significant only for IO (F=7.458, p=0.009) indicating that AH maneuver increased the thickness of IO in men. Interaction effect of posture and muscle status on muscular thickness indicated that changing position only affects the resting thickness of TrA (F=5.617, p=0.023). Standing posture significantly affected the TrA contraction ratio (t=3.122, p=0.003) and TrA preferential activation ratio (t=2.76, p=0.008). There was no relationship between age and muscle thickness (r=0.262, p=0.09). The PBF has been introduced as a clinical and available device for monitoring TrA activity, while RUSI showed that both TrA and IO muscles had activated after AH maneuver. We recommend performing further investigations using electromyography and RUSI simultaneously at more functional postures such as upright standing. PMID:21147426

Manshadi, Farideh Dehghan; Parnianpour, Mohamad; Sarrafzadeh, Javad; Azghani, Mahmood Reza; Kazemnejad, Anooshirvan

2011-01-01

238

Repair of Abdominal Wall Defects In Vitro and In Vivo Using VEGF Sustained-Release Multi-Walled Carbon Nanotubes (MWNT) Composite Scaffolds  

PubMed Central

Objective Porcine acellular dermal matrices (ADM) have been widely used in experimental and clinical research for abdominal wall repair. Compared to porcine small intestinal submucosa (SIS), the effect of these matrices on the regenerative capacity of blood vessels is still not ideal. Multi-walled carbon nanotubes (MWNTs) can more effectively transport VEGF to cells or tissues because of their large specific surface area and interior cavity. In this study, we explored the safety and efficacy of implanted VEGF-loaded MWNT composite scaffolds in vitro and vivo to repair abdominal wall defects. Materials and Methods VEGF-loaded MWNTs were prepared by a modified plasma polymerization treatment. Four composite scaffolds were evaluated for cytotoxicity, proliferation, and release dynamics. We created 3 cm×4 cm abdominal wall defects in 43 Sprague-Dawley rats. After implantation times of 2, 4, 8, and 12 weeks, the scaffolds and the surrounding tissues were collected and examined by gross inspection, biomechanical testing, and histological examination. Results A 5–10 nm poly(lactic-co-glycolic acid) (PLGA) film was evenly distributed on MWNTs. The 3% MWNT composite group showed lower cytotoxicity and appropriate release performance, and it was thus tested in vivo. In rats with the 3% composite implanted, host cells were prevented from migrating to the ADM at 2 weeks, vascularization was established more rapidly at 12 weeks, and the values for both the maximum load and the elastic modulus were significantly lower than in the ADM-alone group (p<0.01). Histological staining revealed that the MWNT was still not completely eliminated 12 weeks after implantation. Conclusion MWNTs were able to carry VEGF to cells or tissues, and the 3% MWNT composite material showed lower cytotoxicity and had an appropriate release performance, which prompted faster vascularization of the ADM than other scaffolds. Nevertheless, the MWNTs induced harmful effects that should be carefully considered in biomedical studies.

Yang, Jianjun; Liu, Zhengni; Peng, Zhiyou; Tang, Rui; Gu, Yan

2013-01-01

239

Effects of the Transient Blood Flow-Wall Interaction on the Wall Stress Distribution in Abdominal Aortic Aneurysm (AAA)  

NASA Astrophysics Data System (ADS)

Our static finite element analysis (FEA) of both idealized and real clinical models has shown that the maximum diameter and asymmetry have substantial influence on the AAA wall stress distribution. The thrombus inside the AAA was also found to reduce the magnitude of the wall stresses. To achieve a better understanding of the wall stress distribution in real AAAs, a dynamic FEA was also performed. We considered models, both symmetric and non-symmetric, in which the aorta is assumed isotropic with nonlinear material properties. For the limiting case of rigid walls, the evolution of the flow pattern and the wall shear stresses due to fluid flow at different stages of cardiac cycle predicted by our simulations are compared with experimental results obtained in in-vitro models. A good agreement is found between both results. Finally, we have extended the analysis to the physiologically correct case of deformable walls and characterized the transient effects on the wall stresses.

Tang, Rubing; Geindreau, Christian; Lasheras, Juan

2006-11-01

240

Stability of thin-walled high-pressure cylindrical pipes with non-circular cross-section and variable wall thickness subjected to non-homogeneous corrosion  

Microsoft Academic Search

This paper proposes a method for determining the critical time of stability loss of thin-walled cylindrical pipes with non-circular cross-section and variable wall thickness along the directrix subjected to non-homogeneous corrosion from the inside. The method is based upon the model of a thin elastic cylindrical shell with a non-circular cross-section and variable wall thickness along the directrix. It is

E. M. Gutman; J. Haddad; R. Bergman

2005-01-01

241

Abdominal Pain Syndrome  

MedlinePLUS

... of the structures within the abdomen or the abdominal wall. In addition, pain messages originating in the chest, ... lungs) Pulmonary embolism (blood clots to the lungs) Abdominal or chest wall pain: Shingles (herpes zoster infection) Costochondritis (inflammation of ...

242

Critical analysis of strattice performance in complex abdominal wall reconstruction: intermediate-risk patients and early complications.  

PubMed

Abstract The purpose of this study was to analyze the performance of a porcine-derived acellular dermal matrix (Strattice Reconstructive Tissue Matrix) in patients at increased risk for perioperative complications. We reviewed medical records for patients with complex abdominal wall reconstruction (AWR) and Strattice underlay from 2007 to 2010. Intermediate-risk patients were defined as having multiple comorbidities without abdominal infection. Forty-one patients met the inclusion criteria (mean age, 60 years; mean body mass index, 35.5 kg/m(2)). Comorbidities included coronary artery disease (63.4%), diabetes mellitus (36.6%), and chronic obstructive pulmonary disease (17.1%). Fascial closure was achieved in 40 patients (97.6%). Average hospitalization was 6.4 days (range, 1-24 days). Complications included seroma (7.3%), wound dehiscence with Strattice exposure (4.9%), cellulitis (2.4%), and hematoma (2.4%). All patients achieved abdominal wall closure with no recurrent hernias or need for Strattice removal. Patients with multiple comorbidities at intermediate risk of postoperative complications can achieve successful, safe AWR with Strattice. PMID:24229027

Patel, Ketan M; Albino, Frank P; Nahabedian, Maurice Y; Bhanot, Parag

2013-01-01

243

Bacteria in sputum of stable severe asthma and increased airway wall thickness  

PubMed Central

Background Patients with chronic asthma have thicker intrapulmonary airways measured on high resolution computed tomography (HRCT). We determined whether the presence of lower airway bacteria was associated with increased airway wall thickness. Methods In 56 patients with stable severe asthma, sputum specimens obtained either spontaneously or after induction with hypertonic saline were cultured for bacteria and thoracic HRCT scans obtained. Wall thickness (WT) and area (WA) expressed as a ratio of airway diameter (D) and total area, respectively, were measured at five levels. Results Positive bacterial cultures were obtained in 29 patients, with H. influenzae, P. aeruginosa and S. aureus being the commonest strains. Logistic regression analysis showed that this was associated with the duration of asthma and the exacerbations during the past year. In airways > 2 mm, there was no significant difference in WA (67.5 ± 5.4 vs 66.4 ± 5.4) and WT/D (21.6 ± 2.7 vs 21.3 ± 2.4) between the culture negative versus positive groups. Similarly, in airways (? 2 mm), there were no significant differences in these parameters. The ratio of ?wall area to Pi was negatively correlated with FEV1% predicted (p < 0.05). Conclusions Bacterial colonization of the lower airways is common in patients with chronic severe asthma and is linked to the duration of asthma and having had exacerbations in the past year, but not with an increase in airway wall thickness.

2012-01-01

244

Ultrasonographic Study of Gallbladder Wall Thickness and Emptying in Cirrhotic Patients without Gallstones  

PubMed Central

Background and Aim. Gallbladder wall thickening and impaired contractility are currently reported in cirrhotic patients and often related to portal hypertension and hepatic failure. The purpose of this work was to evaluate, by ultrasonographic method, gallbladder wall thickness and gallbladder emptying after a standard meal in normal subjects and in patients with compensated liver cirrhosis without gallstones. Methods. Twenty-three patients with Child-Pugh class A liver cirrhosis and twenty healthy controls were studied. Gallbladder wall thickness (GWT), gallbladder fasting volume (FV), residual volume (RV), and maximum percentage of emptying (%E) were calculated. Measurements of mean portal velocity, portal vein flow, and serum albumin were performed too. Statistical analysis was assessed by Student's “t test” for unpaired data. Results. GWT was 0.60 ± 0.22 cm in cirrhotic patients and 0.21 ± 0.06 cm in controls (P < .0001). FV and RV were, respectively, 37.8 ± 3.7 cm3 and 21.8 ± 3 cm3 in cirrhotic patients, 21.9 ± 4.2 cm3 and 4.6 ± 2.2 cm3 in healthy volunteers (P < .0001). %E was smaller in cirrhotics (42.6 ± 7.8) as compared to controls (80.3 ± 7.2; P < .0001). Conclusions. In patients with compensated liver cirrhosis without gallstones gallbladder wall thickness is increased whereas its contractility is reduced. These early structural and functional alterations could play a role in gallstone formation in more advanced stages of the disease.

Loreno, Massimiliano; Travali, Salvatore; Bucceri, Anna Maria; Scalisi, Giuseppe; Virgilio, Carla; Brogna, Alfio

2009-01-01

245

Alveolar Antral Artery: Does its Diameter Correlate with Maxillary lateral wall Thickness in Dentate Patients?  

PubMed Central

Introduction: Knowledge of the presence of the alveolar antral artery in the lateral maxillary sinus wall is essential for surgeons who operate in this region. The purpose of this study was to investigate the correlation between alveolar antral artery diameter and lateral maxillary bony wall thickness in dentate patients. Materials and Methods: Thirty five Cone-Beam Computed Tomography (CBCT) scans from 35 dentate patients were selected in coronal sections in three locations; second premolar (P2), first molar (M1), and second molar (M2). The presence of the alveolar antral artery in each situation was determined and the bone thickness in the region of alveolar antral artery was measured perpendicular to the lateral wall of the maxilla. Results: The alveolar antral artery was present in 67.1% CBCTs. The difference between the alveolar antral artery diameter was only significant in the first and second molar area (P=0.039).There were significant differences between bone thickness in three locations, with the thickest bone in the first molar area followed by the second molar and second premolar, respectively. The correlation coefficient showed that there is a positive correlation between bone thickness and alveolar antral artery diameter. Conclusion: This study showed that the thicker the bones in dentate patients, the greater the chance of interference with the large caliber intra-osseous alveolar antral artery.

Rahpeyma, Amin; Khajehahmadi, Saeedeh; Amini, Parvin

2014-01-01

246

The effect of fig wall thickness in Ficus erecta var. beecheyana on parasitism  

NASA Astrophysics Data System (ADS)

Fig wasp communities constitute a model system to analyse determinants of community complexity and to investigate how biological interaction networks are maintained. It has been suggested for monoecious figs, that fig pollinating wasps avoid ovipositing in flowers located close to the fig wall because of strong parasitic pressure by wasps ovipositing through the fig wall. This behaviour could help explain why mainly seeds are produced in flowers located close to the fig wall, thus stabilizing the fig-pollinating wasp mutualism. In this contribution we explore, for dioecious figs, whether ovipositor length of parasitic species may really be limiting. In dioecious figs, functionally male figs produce pollinating wasps and pollen while female figs produce only seeds, facilitating selection of traits favouring pollinator reproduction in male figs. We show in Ficus erecta that fig walls are thicker in male figs than in female figs. Male figs presenting thick walls, thicker than the length of the parasites' ovipositors, went unparasitized while male figs presenting thinner walls were systematically parasitized. Hence, in F. erecta, ovipositor length of the parasites is limiting access to some figs. However, we also show that in another dioecious species, Ficus formosana, presenting thin walled male figs, no fig is protected against oviposition by its two parasites. Hence in dioecious as well as in monoecious figs, in some Ficus species, ovipositors of the parasites are limiting access to ovules, while in other Ficus species all ovules are exposed to parasitism.

Tzeng, Hsy-Yu; Ou, Chern-Hsiung; Lu, Fu-Yuan; Bain, Anthony; Chou, Lien-Siang; Kjellberg, Finn

2014-05-01

247

Abdominal wall-lifting versus CO2 pneumoperitoneum in laparoscopy: a review and meta-analysis  

PubMed Central

The aim of this study is to compare the operative parameters and outcomes of conventional CO2-pneumoperitoneum (PP) versus gasless abdominal wall-lifting (AWL) for laparoscopic surgery. The literature databases of PubMed, Google Scholar and Cochrane Library were searched for randomized controlled trials (RCTs) that had compared the CO2-PP approach with that of gasless AWL for laparoscopic surgery and which had been published between 1995 and 2012. Data for the operative parameters (i.e. surgery duration, intraoperative heart rate (HR), perioperative complications, and postoperative duration of hospital stay and time to activity) and outcomes (postoperative shoulder pain, nausea/vomiting (PONV), partial pressure of CO2 in the blood (PaCO2), blood pH, and serum levels of the inflammatory cytokine interleukin (IL)-6) were extracted from the identified RCTs. RevMan software, version 5.2, was used for data synthesis and statistical analysis. Nineteen RCTs were selected for the meta-analysis, involving a total of 791 patients who had undergone laparoscopic operations with CO2-PP (n = 399) or gasless AWL (n = 392). Sub-group analysis indicated that the patients who underwent gasless AWL had significantly shorter postoperative time to activity (weighted mean difference (WMD) = -0.23 d, 95% confidence interval (CI): -0.37 to -0.09; P = 0.001), lower incidence of PONV (odds ratio (OR) = 0.24, 95% CI: 0.10 to 0.57; P = 0.001) and lower postoperative PaCO2 level (WMD = -3.09 mmHg, 95% CI: -4.66 to -1.53; P = 0.0001), compared to the patients who underwent CO2-PP. However, the CO2-PP method was associated with a significantly shorter surgery duration than the gasless AWL method (WMD = 8.61, 95% CI: 3.19 to 14.03; P = 0.002). There were no significant advantages detected for either approach with respect to the intraoperative HR, the perioperative complication rate, or the postoperative parameters of duration of hospital stay, shoulder pain, blood pH, or serum IL-6 level. We concluded form present study that the gasless AWL method has the features of shorter time, lower postoperative PaCO2, and lower PONV incidence while the CO2-PP method for laparoscopy requires shorter surgical time.

Ren, Hao; Tong, Yao; Ding, Xi-Bing; Wang, Xin; Jin, Shu-Qing; Niu, Xiao-Yin; Zhao, Xiang; Li, Quan

2014-01-01

248

Images in plastic surgery: the anatomy of macrovascular arteriovenous shunts and implications for abdominal wall free flaps.  

PubMed

With the increasing use of preoperative imaging of the abdominal vasculature prior to free flaps based on the abdominal wall, the identification of a previously undescribed anatomic structure has, that of large-vessel (macroscopic) arteriovenous communications, has emerged. These macrovascular arteriovenous shunts are observed in most patients, and provide a communication between the arterial perforators of the deep inferior epigastric artery and the superficial inferior epigastric vein. These communications provide vascular shunting occurring prior to capillary filling and have potentially profound clinical implications and therapeutic possibilities in a range of medical and surgical conditions. Although these have been demonstrated previously on computed tomographic angiography imaging, their macroscopic and microscopic anatomy has not been described. We present images in vivo, ex vivo, and histologically to highlight their anatomic features. PMID:21734478

Rozen, Warren M; Chubb, Daniel; Ashton, Mark W; Whitaker, Iain S; Grinsell, Damien

2011-08-01

249

Bobbin-Tool Friction-Stir Welding of Thick-Walled Aluminum Alloy Pressure Vessels  

Microsoft Academic Search

It was desired to assemble thick-walled Al alloy 2219 pressure vessels by bobbin-tool friction-stir welding. To develop the welding-process, mechanical-property, and fitness-for-service information to support this effort, extensive friction-stir welding-parameter studies were conducted on 2.5 cm. and 3.8 cm. thick 2219 Al alloy plate. Starting conditions of the plate were the fully-heat-treated (-T62) and in the annealed (-O) conditions. The

E C Dalder; J W Pastrnak; J Engel; R S Forrest; E Kokko; K M Ternan; D Waldron

2007-01-01

250

Elastic analysis of heterogeneous thick-walled spherical pressure vessels with parabolic varying properties  

NASA Astrophysics Data System (ADS)

On the basis of plane elasticity theory (PET), the displacement and stress components in a thick-walled spherical pressure vessels made of heterogeneous materials subjected to internal and external pressure is developed. The mechanical properties except the Poisson's ratio are assumed to obey the parabolic variations throughout the thickness. Effect of material inhomogeneity on the elastic deformations and stresses is investigated. The analytical solutions and the solutions carried out through the FEM have a good agreement. The values used in this study are arbitrary chosen to demonstrate the effect of inhomogeneity on displacements, and stresses distributions.

Karami, Keyhan; Abedi, Majid; Zamani Nejad, Mohammad; Lotfian, Mohammad Hassan

2012-12-01

251

Erosion of small intestine with necrotising fasciitis of over lying abdominal wall after expanded poly-tetrafluoroethylene mesh implantation: A rare complication after laparoscopic incisional hernia repair  

PubMed Central

Complications such as bowel erosions, enterocutaneous fistulae are rare with the use of expandedpoly-tetrafluoroethylene (ePTFE) mesh in laparoscopic incisional hernia repair (LIHR). This unusual case patient presented to us with necrotising fasciitis of overlying anterior abdominal wall with peritonitis withsepticaemia and underwent aLIHR6 weeks before, which has not been reported till yet. We report a case of LIHR, presented to us with necrotising fasciitis of overlying anterior abdominal wall, peritonitis and septicaemia which was managed by small bowel segmental resection and exteriorisation of the ends, debridement of overlying anterior abdominal wall and maximum resection of implanted mesh. This case is unusual secondary to long experience with ePTFE mesh and the lack of published cases similar to this one. A brief review of relevant literature has been included in the article. We recommend pre-peritoneal placement of dual mesh fixed preferably by trans-abdominal polypropylene suture in LIHR.

Shrivastava, Ashish; Gupta, Akshara; Gupta, Achal; Shrivastava, Jyoti

2013-01-01

252

Measurement of fetal abdominal and subscapular subcutaneous tissue thickness during pregnancy to predict macrosomia: a pilot study.  

PubMed

This study assessed the growth trends and reference ranges of the ultrasound parameters, fetal abdominal subcutaneous tissue thickness (ASTT) and subscapular subcutaneous tissue thickness (SSTT), in the last two trimesters of normal pregnancy in a Chinese population. We recruited 744 healthy women with singleton pregnancies. The ASTT and SSTT were evaluated at different times between 21 and 36 weeks of gestation. The correlations between these parameters and fetal gestational weeks were assessed using linear regression analysis. Both ASTT and SSTT increased with gestation, and both parameters showed a strong correlation with gestation (ASTT vs. GA, R(2)?= 0.792; P<0.0001; SSTT vs. GA, R(2)?= 0.302; P<0.0001). Time-specific reference ranges, including 5th, 50th and 95th percentiles and means ± SD, were constructed for ASTT and SSTT. These results provide a preliminary reference range to evaluate whether fetal development and maternal metabolic health is normal or not in a Chinese population. PMID:24675769

Chen, Ling; Wu, Jing-Jing; Chen, Xiao-Hui; Cao, Li; Wu, Yun; Zhu, Li-Jun; Lv, Kang-Tai; Ji, Chen-Bo; Guo, Xi-Rong

2014-01-01

253

A thermoelastic transversely isotropic thick walled cylinder/disk application: An analytical solution and study  

NASA Technical Reports Server (NTRS)

A continuum theory is utilized to represent the thermoelastic behavior of a thick walled composite cylinder that can be idealized as transversely isotropic. A multiaxial statement of the constitutive theory employed is presented, as well as the out of the plane of isotropy, plane stress, and plane strain reductions. The derived analytical solution presented is valid for a cylindrical tube or thin disk with a concentric hole, subjected to internal and/or external pressure and a general radial temperature distribution. A specific problem examined is that of a thick walled cylinder subjected to an internal and external pressure loading and a linear radial temperature distribution. The results are expressed in nondimensional form and the effects on the response behavior are examined for various material properties, fiber orientation and types of loadings.

Arnold, S. M.

1989-01-01

254

Separation occurring during the drop weight tear test of thick-walled X80 pipeline steels  

NASA Astrophysics Data System (ADS)

A separation phenomenon occurring during the drop weight tear test of commercial thick-walled API (American Petroleum Institute) X80 strip steel was investigated in this work. Microstructural analysis showed that the band structure of bainite elongated along the rolling direction works as the initiation sites of separation. The propagation of separation can be promoted not only by the occurrence of the band structure of martensite/austenite constituent, prior austenite grain boundaries, and elongated bainite, but also by fine acicular ferrite and bainite. Wide separation formed in the former case, while the narrow one appeared in the latter case. Some methods were proposed to obtain fine and homogeneous acicular ferrite in thick-walled X80 pipeline steel in order to minimize the occurrence of separation.

Sha, Qing-yun; Li, Da-hang; Huang, Guo-jian; Guan, Ju

2013-08-01

255

Sex-Related Differences of Cortical Thickness in Patients with Chronic Abdominal Pain  

PubMed Central

Background & Aims Regional reductions in gray matter (GM) have been reported in several chronic somatic and visceral pain conditions, including irritable bowel syndrome (IBS) and chronic pancreatitis. Reported GM reductions include insular and anterior cingulate cortices, even though subregions are generally not specified. The majority of published studies suffer from limited sample size, heterogeneity of populations, and lack of analyses for sex differences. We aimed to characterize regional changes in cortical thickness (CT) in a large number of well phenotyped IBS patients, taking into account the role of sex related differences. Methods Cortical GM thickness was determined in 266 subjects (90 IBS [70 predominantly premenopausal female] and 176 healthy controls (HC) [155 predominantly premenopausal female]) using the Laboratory of Neuro Imaging (LONI) Pipeline. A combined region of interest (ROI) and whole brain approach was used to detect any sub-regional and vertex-level differences after removing effects of age and total GM volume. Correlation analyses were performed on behavioral data. Results While IBS as a group did not show significant differences in CT compared to HCs, sex related differences were observed both within the IBS and the HC groups. When female IBS patients were compared to female HCs, whole brain analysis showed significant CT increase in somatosensory and primary motor cortex, as well as CT decrease in bilateral subgenual anterior cingulate cortex (sgACC). The ROI analysis showed significant regional CT decrease in bilateral subregions of insular cortex, while CT decrease in cingulate was limited to left sgACC, accounting for the effect of age and GM volume. Several measures of IBS symptom severity showed significant correlation with CT changes in female IBS patients. Conclusions Significant, sex related differences in CT are present in both HCs and in IBS patients. The biphasic neuroplastic changes in female IBS patients are related to symptom severity.

Jiang, Zhiguo; Dinov, Ivo D.; Labus, Jennifer; Shi, Yonggang; Zamanyan, Alen; Gupta, Arpana; Ashe-McNalley, Cody; Hong, Jui-Yang; Tillisch, Kirsten; Toga, Arthur W.; Mayer, Emeran A.

2013-01-01

256

Optimum design method for double-layer thick-walled concrete cylinder with different modulus  

Microsoft Academic Search

The stress state of thick-walled cylinder will be improved when it is composed of multi-layer concrete with different Young’s\\u000a modulus of elasticity. The optimum design method for double-layer concrete cylinders is discussed in this paper. When the\\u000a modulus of the inner-layer concrete is less than the outer one, the stress concentration on the cylinder inner surface will\\u000a be relieved and

Ai-Zhong Lu; Gui-Sheng Xu; Lu-Qing Zhang

2011-01-01

257

Development of the titanium structure in explosive collapse of thick-walled cylinders  

Microsoft Academic Search

The dependence of the titanium structure on the total deformation in the explosive collapse of thick-walled cylinders is studied.\\u000a It is shown that structure evolution as a whole and the critical parameters for the appearance of an unstable plastic flow\\u000a in titanium are not the functions of the final deformation of the cylinders. This instability, which is governed by the

M. P. Bondar; O. L. Pervukhina; V. F. Nesterenko; Ya. L. Luk’yanov

1998-01-01

258

Accurate Segmentation of the Left Ventricle in Computed Tomography Images for Local Wall Thickness Assessment  

Microsoft Academic Search

\\u000a In recent years, the fully automatic segmentation of the whole heart from three-dimensional (3D) CT or MR images has become\\u000a feasible with mean surface accuracies in the order of 1mm. The assessment of local myocardial motion and wall thickness for\\u000a different heart phases requires highly consistent delineation of the involved surfaces. Papillary muscles and misleading pericardial\\u000a structures lead to challenges

Jochen Peters; Jonathan Lessick; Reinhard Kneser; Irina Wächter; M. Vembar; Olivier Ecabert; Jürgen Weese

2010-01-01

259

Adaptive ultrasonic measurement of blood vessel diameter and wall thickness: theory and experimental results  

Microsoft Academic Search

An adaptive ultrasonic technique for measuring blood vessel diameter and wall thickness is presented. This technique allows one to use a target-specific transmitted waveform\\/receiver filter to obtain a larger signal-to-noise ratio (SNR) in the received signal than conventional techniques. Generally, SNR of a received wave increases as the intensity of the transmit wave increases; however, because of the FDA limitations

K. Rafii; J. S. Jaffe

1998-01-01

260

Increased wall thickness using ultrasonography is associated with inflammation in an animal model of experimental colitis  

PubMed Central

Experimentally induced colitis is used in animals to investigate pathophysiological mechanisms in inflammatory bowel disease. When following disease course and treatment effects, it should be possible to perform repeated measurements without harming the animals. This pilot study was performed to investigate whether transabdominal ultrasound using a clinical scanner could be used on rats to demonstrate bowel inflammation in an experimental colitis model. Colitis was induced by either 5% dextran sodium sulfate (DSS) in drinking water for 7 days or a single dose of intracolonic trinitrobenzene sulfonic acid (TNBS). Using ultrasonography, wall thickness of distal colon, cecum, and small bowel was recorded prior to and after DSS, and prior to, 2, and 7 days after TNBS. Blood (tumor necrosis factor [TNF]-alpha) and fecal samples (HemoFEC occult blood) were taken from each group on the same days as sonography. Thereafter, rats were killed and specimens for histology were taken. Wall thickness of distal colon, not of cecum or small bowel, increased significantly after 7 days of DSS, and wall thickness of both distal colon and small bowel increased on day 2 and 7 after TNBS. TNF-alpha increased after 7 days in the latter group only. There was a significant correlation between ultrasonographic measurements and combined histology score of distal colon in the DSS group. HemoFEC was also positive in accordance with sonographic and histological features. Increased intestinal wall thickness in response to both DSS- and TNBS-induced colitis was able to be visualized by transabdominal sonography. Moreover, ultrasound findings, occult blood sampling, and histological findings supported each other, indicating that ultrasonography can be used to assess inflammation in a rat experimental model.

Lied, Gulen Arslan; Milde, Anne Marita; Nylund, Kim; Mujic, Maja; Grimstad, Tore; Hausken, Trygve; Gilja, Odd Helge

2012-01-01

261

Finite elastic eversion of a thick-walled incompressible spherical cap  

Microsoft Academic Search

For perfectly elastic rubber-like materials, which are capable of undergoing extremely large deformations, the number of exact solutions remains limited, especially in the context of fully three-dimensional deformations. Here a simple exact solution describing the finite elastic eversion of a sector of a thick-walled incompressible spherical shell is determined for the modified Varga elastic material. This new solution, which describes

J. M. Hill

2000-01-01

262

THERMOELASTIC ANALYSIS OF THICK-WALLED FINITE-LENGTH CYLINDERS OF FUNCTIONALLY GRADED MATERIALS  

Microsoft Academic Search

A semianalytical thermoelasticity solution for thick-walled finite-length cylinders made of functionally graded (FG) materials is presented. The governing partial differential equations are reduced to ordinary differential equations using Fourier expansion series in the axial coordinate. The radial domain is divided into some virtual subdomains in which the power-law distribution is used for the thermomechanical properties of the constituent components. Imposing

M. Ruhi; A. Angoshtari; R. Naghdabadi

2005-01-01

263

Preparation of poly(L-lactic acid)-modified polypropylene mesh and its antiadhesion in experimental abdominal wall defect repair.  

PubMed

A new type of polypropylene (PP) hernia mesh, modified with poly(L-lactic acid) (PLLA), was developed and used to repair rat abdominal wall defect. The PP mesh was first treated with oxygen plasma and then grafted with PLLA in phosphorus pentachloride (PCl5 ) solution in dichloride methane. The water contact angle changed during the procedure, and the coverage percentage of PLLA on the PP was about 80%. ATR-FTIR spectroscopy measurements showed the existence of carbonyl group absorption peak (1756.9 cm(-1) ), and atomic force microscope and scanning electron microscope morphological observation indicated that the surface of the PP mesh was covered with PLLA graft. X-ray photoelectron spectroscopy spectra was used to probe chemical group changes and confirmed that the PLLA was grafted onto the PP. A total of 36 Sprague-Dawley rats were randomly divided into six groups, and they received either modified meshes (experimental groups) or PP meshes (control groups) to repair abdominal wall defects. All animals survived until the end of the experiment. Rats in each group were dissected after the operation (after 1 week, 2 weeks, and 1 month, respectively), and the adhesion effects were evaluated. Sections of the mesh parietal peritoneum overlap were examined histologically and graded for inflammation reaction. Compared with the control groups, the experimental groups showed a better ability to resist peritoneal cavity adhesions (P < 0.05), and there was no increase in inflammation formation (P > 0.05). This new type of PLLA-modified PP mesh displayed an additional property of antiadhesion in animal abdominal wall defect repair. PMID:23661568

Zhang, Zhigang; Zhang, Tianzhu; Li, Junsheng; Ji, Zhenling; Zhou, Hemei; Zhou, Xuefeng; Gu, Ning

2014-01-01

264

Collapsing of Thick-Walled Cylinders Using Electro-Magnetic Driving Forces  

NASA Astrophysics Data System (ADS)

The Thick-Walled Cylinder technique, reported in the literature, uses explosive loading to enforce collapsing of the cylindrical sample. This experimental set-up has been established as a controlled and repeatable technique to create and study multiple adiabatic shear bands. Searching to establish a simpler experimental platform to perform large sets of experiments, we have designed an Electro-Magnetic (EM) set-up for the collapsing of thick walled cylinders. The EM set-up is based on a pulsed current generator using a capacitor bank system. The specimen is an assembly of coaxial cylinders, where the inner and outer cylinders, each attached to an opposite pole, are short-circuited. Upon discharge, a high current flows through the cylinders, in opposite directions, creating repulsive magnetic forces between them. This work presents the design procedure of the specimens using numerical simulations and some experimental results for SS304L thick-walled samples, using this set-up. The spatial distribution of the multiple adiabatic shear bands in these experiments is in good agreement with that reported in the literature for the explosive driven experiments with a similar material.

Lovinger, Zev; Rikanati, Avi; Rittel, Daniel; Rosenberg, Zvi

2009-06-01

265

Analysis Procedures for Double-Shell Target Concentricity and Wall Thickness  

SciTech Connect

The LLNL Target Fabrication Team (TFT) asked the Center for Non-Destructive Characterization (CNDC) to use CNDC's KCAT or Xradia's Micro computed tomography (CT) system to collect three-dimensional (3D) tomographic data of a set of double-shell targets and determine, among other items, the following: (1) the concentricity of the outer surface of the inner shell with respect to the inner surface of the outer shell with an accuracy of 1-2 micrometers, and (2) the wall thickness uniformity of the outer shell with an accuracy of 1-2 micrometers. The CNDC used Xradia's Micro CT system to collect the data. Bill Brown performed the concentricity analysis, and John Sain performed the wall thickness uniformity analysis. Harry Martz provided theoretical guidance, and Dan Schneberk contributed technical (software) support. This document outlines the analysis procedures used in each case. The double-shell targets, as shown in Figures 1 and 2, consist of an inner shell (or capsule), a two-piece spherical aerogel intermediary shell, and a two-piece spherical outer shell. The three elements are designed and fabricated to be concentric--with the aerogel shell acting as a spacer between the inner shell and outer shell--with no to minimum air gaps in the final assembly. The outer diameters of the aerogel and outer shells are 444 and 550 micrometers, respectively, so the wall thickness of the outer shell is 53 micrometers.

Sain, J D; Brown, W D; Martz, H E; Schneberk, D J

2006-03-02

266

Influence of surrounding wall thickness on the fatigue resistance of molars restored with ceramic inlay.  

PubMed

The purpose of this study was to evaluate the influence of buccal and lingual wall thickness on the fatigue resistance of molars restored with CAD/CAM ceramic inlays. Forty human third molars were selected and divided into 4 groups, according to the remaining surrounding wall thickness chosen for inlay preparation (n = 10): G1, 2.0 mm; G2, 1.5 mm; G3, 1.0 mm; G4, 0.5 mm. All inlays were made from feldspathic ceramic blocks by a CAD/CAM system, and cemented adhesively. After 1 week stored in distilled water at 37 °C, the specimens were subjected to fatigue testing under the following protocol: 5Hz; pre-load of 200 N for 5,000 cycles, followed by increasing loads of 400, 600, 800, 1000, 1200 and 1400 N for 30,000 cycles each. The specimens were cycled until failure or completion of 185,000 cycles. The survival rate of the groups was compared using the Kaplan-Meier survival curves (p > 0.05). All specimens withstood the fatigue protocol (185,000 cycles), representing a 100% survival rate. The Kaplan-Meier survival curves showed no difference between groups. It can be concluded that the remaining tooth wall thickness did not influence the fatigue resistance of molars restored with CAD/CAM ceramic inlays. PMID:24918366

Shibata, Shizuma; Gondo, Renata; Araújo, Elito; Roesler, Carlos Rodrigo De Mello; Baratieri, Luiz Narciso

2014-06-11

267

Automatic identification and validation of planar collagen organization in the aorta wall with application to abdominal aortic aneurysm.  

PubMed

Arterial physiology relies on a delicate three-dimensional (3D) organization of cells and extracellular matrix, which is remarkably altered by vascular diseases like abdominal aortic aneurysms (AAA). The ability to explore the micro-histology of the aorta wall is important in the study of vascular pathologies and in the development of vascular constitutive models, i.e., mathematical descriptions of biomechanical properties of the wall. The present study reports and validates a fast image processing sequence capable of quantifying collagen fiber organization from histological stains. Powering and re-normalizing the histogram of the classical fast Fourier transformation (FFT) is a key step in the proposed analysis sequence. This modification introduces a powering parameter w, which was calibrated to best fit the reference data obtained using classical FFT and polarized light microscopy (PLM) of stained histological slices of AAA wall samples. The values of w = 3 and 7 give the best correlation (Pearson's correlation coefficient larger than 0.7, R 2 about 0.7) with the classical FFT approach and PLM measurements. A fast and operator independent method to identify collagen organization in the arterial wall was developed and validated. This overcomes severe limitations of currently applied methods like PLM to identify collagen organization in the arterial wall. PMID:24016340

Polzer, Stanislav; Gasser, T Christian; Forsell, Caroline; Druckmüllerova, Hana; Tichy, Michal; Staffa, Robert; Vlachovsky, Robert; Bursa, Jiri

2013-12-01

268

Association Between the Lateral Wall Thickness of the Maxillary Sinus and the Dental Status: Cone Beam Computed Tomography Evaluation  

PubMed Central

Background: Assessment of the lateral wall thickness of the maxillary sinus is very important in decision making for many surgical interventions. The association between the thickness of the lateral wall of the maxillary sinus and the dental status is not well identified. Objectives: To compare the thickness of the lateral wall of the maxillary sinus in individuals with and without teeth to determine if extraction of the teeth can lead to a significant reduction in the thickness of the maxillary sinus lateral wall or not. Patients and Methods: In a retrospective study on fifty patients with an edentulous space, the thickness of the lateral wall of the maxillary sinus,one centimeter above the sinus floor in the second premolar (P2), first molar (M1) and second molar (M2) areas was determined by cone beam computed tomography scans(CBCTs) and a digital ruler in Romexis F software (Planmeca Romexis 2.4.2.R) and it was compared with values measured in fifty dentated individuals. Three way analysis of variance was applied for comparison after confirmation of the normal distribution of data. Results: The mean of the wall thickness in each of these points was lower in patients with edentulous spaces; however it was not significant. There was no association between gender and the thickness of the lateral wall of the maxillary sinus, but location was associated with different thicknesses. Conclusions: The differences in the thickness based on the location and dental status necessitates assessment of the wall thickness of the maxillary sinus in addition to the current evaluation of bone thickness between the sinus floor and the edentulous crest before maxillary sinus surgery.

Khajehahmadi, Saeedeh; Rahpeyma, Amin; Hoseini Zarch, Seyed Hosein

2014-01-01

269

Airway responsiveness and bronchial-wall thickness in asthma with or without fixed airflow obstruction.  

PubMed

To determine whether asthmatic subjects have an increase in airway wall thickness that could enhance airway narrowing during bronchoprovocation, we examined the relationship between airway responsiveness and bronchial wall thickness measured by high-resolution computed tomography (HRCT). We studied 24 nonsmokers with asthma, of whom 13 had a fixed component of airflow obstruction (Group 1) and 11 had an optimal FEV1 of 80% or more of the predicted value (Group 2). These subjects were compared with a control group of 10 nonasthmatic subjects (Group 3). Measurements were taken of each subject's expiratory flows, bronchodilator response, lung volumes, and methacholine responsiveness. All subjects used an inhaled beta 2-agonist on demand, and 19 also used inhaled steroids (13 in a Group 1 and six in Group 2). HRCT sections were obtained at the top and base of the lung and at the level of the intermediary bronchus (IB), although only this last level was found adequate for analysis. The ratio of IB wall thickness to outer diameter (T/D) showed a negative relationship with the outer diameter in Group 1 only. The mean T/D ratio of IB was not significantly different in Groups 1, 2, and 3, with respective values of 0.16 +/- 0.01, 0.15 +/- 0.01, and 0.18 +/- 0.01 at TLC, and 0.16 +/- 0.01, 0.20 +/- 0.01, and 0.19 +/- 0.01 at FRC. In subjects with a fixed component of airflow obstruction, the thicker the airway wall in relation to its diameter, the lower was the PC20 for methacholine. This was not observed in the other study groups. No correlation was found between the T/D ratio and baseline FEV1.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7663797

Boulet, L; Bélanger, M; Carrier, G

1995-09-01

270

Passive mechanical properties of rat abdominal wall muscles suggest an important role of the extracellular connective tissue matrix.  

PubMed

Abdominal wall muscles have a unique morphology suggesting a complex role in generating and transferring force to the spinal column. Studying passive mechanical properties of these muscles may provide insights into their ability to transfer force among structures. Biopsies from rectus abdominis (RA), external oblique (EO), internal oblique (IO), and transverse abdominis (TrA) were harvested from male Sprague-Dawley rats, and single muscle fibers and fiber bundles (4-8 fibers ensheathed in their connective tissue matrix) were isolated and mechanically stretched in a passive state. Slack sarcomere lengths were measured and elastic moduli were calculated from stress-strain data. Titin molecular mass was also measured from single muscle fibers. No significant differences were found among the four abdominal wall muscles in terms of slack sarcomere length or elastic modulus. Interestingly, across all four muscles, slack sarcomere lengths were quite long in individual muscle fibers (>2.4 µm), and demonstrated a significantly longer slack length in comparison to fiber bundles (p < 0.0001). Also, the extracellular connective tissue matrix provided a stiffening effect and enhanced the resistance to lengthening at long muscle lengths. Titin molecular mass was significantly less in TrA compared to each of the other three muscles (p < 0.0009), but this difference did not correspond to hypothesized differences in stiffness. PMID:22267257

Brown, Stephen H M; Carr, John Austin; Ward, Samuel R; Lieber, Richard L

2012-08-01

271

Inverse Transient Analysis for Classification of Wall Thickness Variations in Pipelines  

PubMed Central

Analysis of transient fluid pressure signals has been investigated as an alternative method of fault detection in pipeline systems and has shown promise in both laboratory and field trials. The advantage of the method is that it can potentially provide a fast and cost effective means of locating faults such as leaks, blockages and pipeline wall degradation within a pipeline while the system remains fully operational. The only requirement is that high speed pressure sensors are placed in contact with the fluid. Further development of the method requires detailed numerical models and enhanced understanding of transient flow within a pipeline where variations in pipeline condition and geometry occur. One such variation commonly encountered is the degradation or thinning of pipe walls, which can increase the susceptible of a pipeline to leak development. This paper aims to improve transient-based fault detection methods by investigating how changes in pipe wall thickness will affect the transient behaviour of a system; this is done through the analysis of laboratory experiments. The laboratory experiments are carried out on a stainless steel pipeline of constant outside diameter, into which a pipe section of variable wall thickness is inserted. In order to detect the location and severity of these changes in wall conditions within the laboratory system an inverse transient analysis procedure is employed which considers independent variations in wavespeed and diameter. Inverse transient analyses are carried out using a genetic algorithm optimisation routine to match the response from a one-dimensional method of characteristics transient model to the experimental time domain pressure responses. The accuracy of the detection technique is evaluated and benefits associated with various simplifying assumptions and simulation run times are investigated. It is found that for the case investigated, changes in the wavespeed and nominal diameter of the pipeline are both important to the accuracy of the inverse analysis procedure and can be used to differentiate the observed transient behaviour caused by changes in wall thickness from that caused by other known faults such as leaks. Further application of the method to real pipelines is discussed.

Tuck, Jeffrey; Lee, Pedro

2013-01-01

272

Wall stress and strain analysis using a three-dimensional thick-wall model with fluid–structure interactions for blood flow in carotid arteries with stenoses  

Microsoft Academic Search

Wall mechanics and fluid–structure interactions play important roles in artery collapse and plaque cap rupture, which leads directly to heart attack and stroke. A three-dimensional thick-wall model with fluid–structure interactions was introduced and solved using ADINA to investigate the wall stress and strain distributions and flow properties of blood flow in carotid arteries with symmetric and asymmetric stenoses. The Navier–Stokes

Dalin Tang; Chun Yang; Yan Huang; David N. Ku

1999-01-01

273

Use of surgisis for abdominal wall reconstruction/closure in battlefield casualties during Operation Iraqi Freedom.  

PubMed

A case series and discussion based on experiences gained during Operation Iraqi Freedom are presented. The Army previously published an article on the use of Gore-Tex mesh in the staged closure of open abdominal wounds. We thought that use of a biomaterial could shorten the overall course of abdominal closure and improve outcomes. This is mainly a "proof of concept" type of study. Although class I data are not presented, a useful concept is discussed. To our knowledge, no other report of the use of biomaterials for battle casualties has been published. Several issues that are faced by the military medical system are presented. The use of Surgisis (lyophilized porcine small intestinal submucosa; Cook Biotech, West Lafayette, Indiana) in the described setting is presented as one possible solution. PMID:17985779

Johnson, Eric K; Paquette, Edmond L

2007-10-01

274

The Rayleigh-Benard instability in an enclosure having finite thickness walls  

NASA Astrophysics Data System (ADS)

Natural convection in an enclosure having finite thickness heat-conducting walls at local heating at the bottom of the cavity has been numerically studied. Heat exchange with an environment due to convection and radiation has been considered on one of external sides of the decision region. The governing unsteady three-dimensional flow equations in the Boussinesq approximation for the gas cavity and heat conduction equation for the solid walls, written in dimensionless variables such as vector potential functions, the vorticity vector and the temperature, have been solved using finite difference method. Results have been obtained for a Prandl number of 0.7 and for a Grashof number ranging from 104 to 106.

Kuznetsov, Geniy V.; Sheremet, Mikhail A.

2010-03-01

275

Failure prediction method for hydro forming simulation of thick walled tubes  

NASA Astrophysics Data System (ADS)

The industrial production of thick walled hydro formed steel parts is a process difficult to control. In particular the prevention of cracks in the production of these parts is very important. It is of utmost importance to have a virtual tool to predict forming results. Standard methods for the simulation of hydro formed parts base upon processes using a shell element formulation and implement a forming limit curve (FLC) for crack prediction. But the forming limit curve is limited to the case of linear strain paths. The initial FLC is no longer valid in the case of nonlinear strain paths. Because of the geometric specifications of the investigated parts--thick walls, compact dimensions, high strains--and the known limitations of the forming limit curve--which don't accord to the hydro forming process-- these standard simulation methods are not applicable for the present investigations. A new approach to simulate thick walled hydro formed parts is the use of a volume element formulation in combination with a more complex failure criterion, which gives information about the risk of ductile normal fracture and ductile shear fractures with nonlinear strain paths. The onset of necking must be predicted directly by the volume elements. The aim of this work is to implement the failure criteria in a hydroforming simulation and to compare the results of the simulation with real cracked test parts. The commercial FEM code PamStamp 2G is used as a solver and a comprehensive fracture model is applied. This fracture model distinguishes between two mechanisms responsible for ductile fracture. One is the void growth and coalescence (ductile normal fracture) and the other one is the shear failure model (ductile shear fracture).

Kolleck, Ralf; Auer, Peter; Auer, Gerfried

2011-05-01

276

Evaluating patient-specific abdominal aortic aneurysm wall stress based on flow-induced loading.  

PubMed

In this paper, we develop a physiologic wall stress analysis procedure by incorporating experimentally measured, non-uniform pressure loading in a patient-based finite element simulation. First, the distribution of wall pressure is measured in a patient-based lumen cast at a series of physiologically relevant steady flow rates. Then, using published equi-biaxial stress-deformation data from aneurysmal tissue samples, a nonlinear hyperelastic constitutive equation is used to describe the mechanical behavior of the aneurysm wall. The model accounts of the characteristic exponential stiffening due to the rapid engagement of nearly inextensible collagen fibers and assumes, as a first approximation, an isotropic behavior of the arterial wall. The results show a complex wall stress distribution with a localized maximum principal stress value of 660 kPa on the inner surface of the posterior surface of the aneurysm bulge, a considerably larger value than has generally been reported in calculations of wall stress under the assumption of uniform loading. This is potentially significant since the posterior wall has been suggested as a common site of rupture, and the aneurysmal tensile strength reported by other authors is of the same order of magnitude as the maximum stress value found here. PMID:19578914

Dorfmann, A; Wilson, C; Edgar, E S; Peattie, R A

2010-04-01

277

Assessment of the abdominal wall function after pedicled TRAM flap surgery for breast reconstruction: Use of modified mesh repair for the donor defect  

PubMed Central

Background: The pedicled TRAM flap has been a workhorse of autologous breast reconstruction for decades. However, there has been a rising concern about the abdominal wall donor site morbidity with the use of conventional TRAM flap. This has generally been cited as one of the main reasons for resorting to “abdominal wall friendly” techniques. This study has been undertaken to assess the abdominal wall function in patients with pedicled TRAM flap breast reconstruction. The entire width of the muscle and the overlying wide disk of anterior rectus sheath were harvested with the TRAM flap in all our patients and the anterior rectus sheath defect was repaired by a Proline mesh. Materials and Methods: Abdominal wall function was studied in 21 patients who underwent simultaneous primary unipedicled TRAM flap reconstruction after mastectomy for cancer. In all the patients, the abdominal wall defect was repaired using wide sheet of Proline mesh both as inlay and onlay. The assessment tools included straight and rotational curl ups and a subjective questionnaire. The abdominal wall was also examined for any asymmetry, bulge, or hernia. The minimal follow-up was 6 months postoperative. The objective results were compared with normal unoperated volunteers. Results and Conclusions: The harvesting the TRAM flap certainly results in changes to the anterior abdominal wall that can express themselves to a variable degree. A relatively high incidence of asymptomatic asymmetry of the abdomen was seen. There was total absence of hernia in our series even after a mean follow-up period of 15.5 months. A few patients were only able to partially initiate the sit up movement and suffered an important loss of strength. In most patients, synergists took over the functional movement but as the load increased, flexion and rotation performances decreased. The lack of correlation between exercise tests and the results of the questionnaire suggests that this statistically significant impairment was functionally not important. The patients encountered little or no difficulty in theis day-to-day activities. Our modification of use of a wide mesh as inlay and onlay repair minimizes the donor site morbidity. This also avoids maneuvers meant for primary closure of the rectus sheath defects, which can result in distortion of umbilicus. Therefore, in conclusion, the unipedicled TRAM flap should be regarded as a valuable option in breast reconstruction provided careful repair of the abdominal wall defect is undertaken using Proline mesh.

Cyriac, Chacko; Sharma, Ramesh Kumar; Singh, Gurpreet

2010-01-01

278

An examination of the effect of boundary layer thickness on vortex shedding from a square cylinder near a wall  

Microsoft Academic Search

A computational study has been undertaken to examine the effect of boundary layer thickness ?\\/D on vortex shedding from a square cylinder in proximity to a solid wall. The computations were carried out in a second-moment turbulence modeling framework using a finite-volume technique. The computed results show that, in general, thickening of the wall boundary layer causes wake periodicity to

Anthony G. Straatman; Robert J. Martinuzzi

2003-01-01

279

Abdominal wall reconstruction with components separation and mesh reinforcement in complex hernia repair  

PubMed Central

Background Abdominal closure in the presence of enterocutaneous fistula, stoma or infection can be challenging. A single-surgeon’s experience of performing components separation abdominal reconstruction and reinforcement with mesh in the difficult abdomen is presented. Methods Medical records from patients undergoing components separation and reinforcement with hernia mesh at Royal Liverpool Hospital from 2009 to 2012 were reviewed. Patients were classified by the Ventral Hernia Working Group (VHWG) grading system. Co-morbidities, previous surgeries, specific type of reconstruction technique, discharge date, complications and hernia recurrence were recorded. Results Twenty-three patients’ (15 males, 8 females) notes were reviewed. Median age was 57 years (range 20-76 years). Median follow-up at the time of review was 17 months (range 2-48 months). There were 13 grade III hernias and 10 grade IV hernias identified. Synthetic mesh was placed to reinforce the abdomen in 6 patients, cross-linked porcine dermis was used in 3, and a Biodesign® Hernia Graft was placed in 14. Complications included wound infection (13%), superficial wound dehiscence (22%), seroma formation (22%) and stoma complications (9%). To date, hernias have recurred in 3 patients (13%). Conclusions Components separation and reinforcement with biological mesh is a successful technique in the grade III and IV abdomen with acceptable rate of recurrence and complications.

2014-01-01

280

Beckwith-Wiedemann syndrome, delayed abdominal wall closure, and neonatal intussusception--case report and literature review.  

PubMed

We present the extremely rare case of a male newborn with Beckwith-Wiedemann Syndrome (BWS) presenting as delayed abdominal wall closure and neonatal intussusception. Fetal ultrasound had shown omphalocele that resolved spontaneously. When feeding was attempted, he had various episodes of vomiting. An x-ray showed signs of high bowel obstruction. Jejunal intussusception was found on laparotomy. Enterectomy and primary jejuno-jejunal anastomosis was performed. During post-operative period subtle physical findings became prominent: plain hemangioma, posterior helical indentations, and macroglossia. Cardiac ultrasonography showed a patent foramen oval with small left-to-right shunt. Ultrasonography showed renal hyperplasia. Genetic study showed hypomethylation of DMR2 region of 11p15 chromosome. PMID:22483344

Moreira-Pinto, João; Pereira, Joana; Osório, Angélica; Enes, Carlos; Mota, Céu R

2012-12-01

281

Evaluation of airway wall thickness and air trapping by HRCT in asymptomatic asthma.  

PubMed

The aim of this study was to examine the relationship between the structural changes in large and small airways in asymptomatic asthmatics quantified by high-resolution computed tomography (HRCT) and airflow obstruction. The bronchial wall thickness at the trunk of the apical bronchus (B1) of the right upper lobe was used for assessment of the large airways. Air trapping, evaluated by the ratio of the average CT-determined values for the bilateral upper and lower lung segments at full expiration to that at full inspiration (E/I ratio), was used for assessment of the small airways. Measurements were obtained with a helical HRCT in 24 asymptomatic asthmatics followed by optimal treatment with inhaled and/or oral corticosteroids for >6 months. Prior (20-30 min) to the HRCT examination, all patients were given an inhaled bronchodilator. The ratio of airway wall thickness to outer diameter (T/D) and the percentage wall area (WA%) at the B1 bronchus and the E/I ratio were significantly greater for the 14 asthmatics with deficient reversible airflow obstruction (forced expiratory volume in one second (FEV1) <80% prediced or FEV1/forced vital capacity <70% after bronchodilator inhalation) than for the 10 asthmatics with normal spirometry and seven normal subjects. T/D, WA%, and E/I ratio showed significant negative correlations with FEV1 % pred after bronchodilator inhalation. The E/I ratio also showed significant positive correlations with T/D, WA%, and residual volume/total lung capacity. These findings suggest that, in spite of optimal treatment, structural changes in both large and small airways may simultaneously occur in asthmatics with deficient reversible airflow obstruction. PMID:14680087

Gono, H; Fujimoto, K; Kawakami, S; Kubo, K

2003-12-01

282

The relationship between bladder wall thickness and lower urinary tract symptoms: Does bladder wall thickness change after alpha-blocker therapy with alfuzosin?  

PubMed Central

Introduction: We evaluate the association between lower urinary tract symptoms (LUTS) and bladder wall thickness (BWT) and investigate whether alfuzosin might improve BWT. Methods: We retrospectively reviewed the data of 164 patients with LUTS. Patients were divided into 2 groups according to BWT (Group 1: BWT ?5 mm, n = 69; Group 2: BWT >5 mm, n = 95). Age, international prostate symptom score (IPSS), maximum and average urinary flow rates (Qmax and Qave), quality of life (QoL), postvoid residual (PVR) urine volume, prostate volume and prostate-specific antigen (PSA) were compared between the 2 groups. In total, 102 patients underwent transurethral resection of the prostate (TURP) and 62 patients were treated with alfuzosin. We compared BWT, Qmax, Qave, IPSS, QoL, PVR and PSA before and at the sixth month of alfuzosin therapy. A p value of <0.05 was considered statistically significant. Results: The mean BWT of Group 1 was 3.72 ± 0.56 mm and Group 2 was 6.43 ± 1.13 mm. There was a significant difference between the 2 groups in terms of mean Qmax and PVR. There was no statistical difference between the groups in terms of Qave, IPSS, QoL, prostate volume and PSA. There was significant difference between BWT before (6.8 ± 2.1) and after (4.6 ± 1.3) treatment with alfuzosin in 62 patients (p = 0.02). There was a significant difference between pre- and post-treatment values of mean Qmax, Qave, IPSS, QoL score, and PVR with alfuzosin. Conclusion: BWT is a non-invasive and effective test to evaluate patients with lower urinary tract obstruction and may be used for showing the effectiveness of alpha-blocker therapy in patients with LUTS.

Karakose, Ayhan; Aydogdu, Ozgu; Atesci, Yusuf Ziya

2014-01-01

283

Suitability of Pharmacokinetic Models for Dynamic Contrast-Enhanced MRI of Abdominal Aortic Aneurysm Vessel Wall: A Comparison  

PubMed Central

Purpose Increased microvascularization of the abdominal aortic aneurysm (AAA) vessel wall has been related to AAA progression and rupture. The aim of this study was to compare the suitability of three pharmacokinetic models to describe AAA vessel wall enhancement using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Materials and Methods Patients with AAA underwent DCE-MRI at 1.5 Tesla. The volume transfer constant (Ktrans), which reflects microvascular flow, permeability and surface area, was calculated by fitting the blood and aneurysm vessel wall gadolinium concentration curves. The relative fit errors, parameter uncertainties and parameter reproducibilities for the Patlak, Tofts and Extended Tofts model were compared to find the most suitable model. Scan-rescan reproducibility was assessed using the interclass correlation coefficient and coefficient of variation (CV). Further, the relationship between Ktrans and AAA size was investigated. Results DCE-MRI examinations from thirty-nine patients (mean age±SD: 72±6 years; M/F: 35/4) with an mean AAA maximal diameter of 49±6 mm could be included for pharmacokinetic analysis. Relative fit uncertainties for Ktrans based on the Patlak model (17%) were significantly lower compared to the Tofts (37%) and Extended Tofts model (42%) (p<0.001). Ktrans scan-rescan reproducibility for the Patlak model (ICC?=?0.61 and CV?=?22%) was comparable with the Tofts (ICC?=?0.61, CV?=?23%) and Extended Tofts model (ICC?=?0.76, CV?=?22%). Ktrans was positively correlated with maximal AAA diameter (Spearman’s ??=?0.38, p?=?0.02) using the Patlak model. Conclusion Using the presented imaging protocol, the Patlak model is most suited to describe DCE-MRI data of the AAA vessel wall with good Ktrans scan-rescan reproducibility.

Nguyen, V. Lai; Kooi, M. Eline; Backes, Walter H.; van Hoof, Raf H. M.; Saris, Anne E. C. M.; Wishaupt, Mirthe C. J.; Hellenthal, Femke A. M. V. I.; van der Geest, Rob J.; Kessels, Alfons G. H.; Schurink, Geert Willem H.; Leiner, Tim

2013-01-01

284

[Preventive abdominoplasty using polypropylene prosthesis during primary laparotomy in the elderly and aged patients as a method of prophylaxis to occurrence of the postoperative abdominal wall defects].  

PubMed

The results of preventive abdominoplasty, using polypropylene prosthesis during initial laparotomy performance in 66 patients more than 62 years old, were analyzed. In accordance to the objective and ultrasound investigation data, critical parameters, witnessing anatomic-functional insufficiency of abdominal wall, were confirmed in the patients. Operative interventions were concluded with the laparotomy wound plasty, using polypropylene prosthesis, which was put on lay--in 4 (6.1%) patients, sub lay--in 62 (93.9%). The best results were observed in the abdominal wall prosthesis in accordance to the sub lay method with the rectal abdominal muscles defect elimination, using application of a "the figure of 8 like" sutures with polypropylene thread. PMID:24501986

Vorovsky?, O O

2013-11-01

285

Effect of multi-layer thermal insulation thickness and location on the hypervelocity impact response of dual-wall structures  

NASA Astrophysics Data System (ADS)

Traditional perforation-resistant wall design for long-duration spacecraft consists of a "bumper" that is placed a small distance away from the main "pressure wall" of a spacecraft compartment or module. This concept has been studied extensively as a means of reducing the perforation threat of hypervelocity projectiles such as meteoroids and orbital debris. If a dual-wall system is employed on an earth-orbiting spacecraft, then a blanket of multi-layer insulation (MLI) will typically be included within the dual-wall system for thermal protection purposes. This paper presents the results of an experimental study in which aluminum dual-wall structures were tested under a variety of high-speed impact conditions to study the effect of MLI thickness and location on perforation resistance. The results presented consist of test-by-test comparisons of the damage sustained by similar dual-wall systems with blanket MLI of various thicknesses and at various locations within the dual-wall systems under similar impact loading conditions. The analyses performed revealed that the placement of the MLI had a significant effect on the ballistic limit of the dual-wall structures considered while reducing the thickness of the MLI by as much as 1/3 did not.

Schonberg, William P.

286

Design and current status of CONTINT: continuous versus interrupted abdominal wall closure after emergency midline laparotomy - a randomized controlled multicenter trial [NCT00544583  

PubMed Central

Background The optimal strategy for abdominal wall closure has been an issue of ongoing debate. Available studies do not specifically enroll patients who undergo emergency laparotomy and thus do not consider the distinct biological characteristics of these patients. The present randomized controlled trial evaluates the efficacy and safety of two commonly applied abdominal wall closure strategies in patients undergoing primary emergency midline laparotomy. Methods/design The CONTINT trial is a multicenter, open label, randomized controlled trial with a two-group parallel design. Patients undergoing a primary emergency midline laparotomy are enrolled in the trial. The two most commonly applied strategies of abdominal wall closure after midline laparotomy are compared: the continuous, all-layer suture technique using slowly absorbable monofilament material (two Monoplus® loops) and the interrupted suture technique using rapidly absorbable braided material (Vicryl® sutures). The primary endpoint within the CONTINT trial is an incisional hernia within 12 months or a burst abdomen within 30 days after surgery. As reliable data on this primary endpoint is not available for patients undergoing emergency surgery, an adaptive interim analysis will be conducted after the inclusion of 80 patients, allowing early termination of the trial if necessary or modification of design characteristics such as recalculation of sample size. Discussion This is a randomized controlled multicenter trial with a two-group parallel design to assess the efficacy and safety of two commonly applied abdominal wall closure strategies in patients undergoing primary emergency midline laparotomy. Trial registration NCT00544583

2012-01-01

287

Risk factors in congenital abdominal wall defects (omphalocele and gastroschisi): a study in a series of 265?858 consecutive births  

Microsoft Academic Search

The aim of this study was to describe the prevalence at birth of two abdominal wall defects (AWD), omphalocela and gastroschisis and to identify possible etiologic factors. The AWD came from 265?858 consecutive births of known ouome registered in the registry of congenital malformations of Strasbourg for the period 1979 to 1998. Request information on the child, the pregnancy, the

C. Stoll; Y. Alembik; B. Dott; M. P. Roth

2001-01-01

288

A method of computing the transient temperature of thick walls from arbitrary variation of adiabatic-wall temperature and heat-transfer coefficient  

NASA Technical Reports Server (NTRS)

A method of calculating the temperature of thick walls has been developed in which the time series and the response to a unit triangle variation of surface temperature concepts are used, together with essentially standard formulas for transient temperature and heat flow into thick walls. The method can be used without knowledge of the mathematical tools of its development. The method is particularly suitable for determining the wall temperature in one-dimensional thermal problems in aeronautics where there is a continuous variation of the heat-transfer coefficient and adiabatic-wall temperature. The method also offers a convenient means for solving the inverse problem of determining the heat-flow history when temperature history is known.

Hill, P R

1958-01-01

289

The Effects of Increased Abdominal Pressure on Lung and Chest Wall Mechanics During Laparoscopic Surgery  

Microsoft Academic Search

We tested the hypothesis that increases in pressure in the abdomen (Par,) exerted by CO, insufflation during laparoscopy would increase elastance (E) and resis- tance (R) of both the lungs and chest wall. We measured airway flow and airway and esophageal pressures of 12 anesthetized\\/paralyzed tracheally intubated patients during mechanical ventilation at lo-30\\/min and tidal volume of 250-800 mL. From

Brenda G. Fahy; George M. Barnas; John L. Flowers; Sheryl E. Nagle; Mary J. Njoku

1996-01-01

290

Changes in the wall shear stresses (WSS) during the enlargement of Abdominal Aortic Aneurysms (AAA)  

NASA Astrophysics Data System (ADS)

The changes in the evolution of the spatial and temporal distribution of the WSS and gradients of WSS at different stages of the enlargement of AAAs are important to understand the etiology and progression of this vascular disease, since they affect the wall structural integrity, primarily via the changes induced on the shape, functions and metabolism of the endothelial cells. PIV measurements were performed in aneurysm models, while changing systematically their geometric parameters. We show that, even at very early stages of the disease (dilatation > 30%), the flow separates from the wall and the formation of a large vortex ring followed by internal shear layers leads to the generation of WSS that drastically differ from the healthy vessel. Inside the AAA, the mean WSS decreases to zero and the magnitude of the WSS can be as low as 26% of the value in a healthy vessel. Two regions with distinct patterns of WSS were identified. The region of flow detachment, with oscillatory WSS of very low mean, and the region of flow reattachment, located distally, where large, negative WSS and sustained gradients of WSS are produced as a result of the impact of the vortex ring on the wall.

Salsac, Anne-Virginie; Sparks, Steven R.; Chomaz, Jean-Marc; Lasheras, Juan C.

2004-11-01

291

Facilitating protein crystal cryoprotection in thick-walled plastic capillaries by high-pressure cryocooling.  

PubMed

Many steps in the X-ray crystallographic solution of protein structures have been automated. However, the harvesting and cryocooling of crystals still rely primarily on manual handling, frequently with consequent mechanical damage. An attractive alternative is to grow crystals directly inside robust plastic capillaries that may be cryocooled and mounted on the beamline goniometer. In this case, it is still desirable to devise a way to cryoprotect the crystals, which is difficult owing to the poor thermal conductivity of thick plastic capillary walls and the large thermal mass of the capillary and internal mother liquor. A method is described to circumvent these difficulties. It is shown that high-pressure cryocooling substantially reduced the minimal concentrations of cryoprotectants required to cryocool water inside capillaries without formation of ice crystals. The minimal concentrations of PEG 200, PEG 400 and glycerol necessary for complete vitrification under pressure cryocooling were determined. PMID:19529790

Chen, Yi-Fan; Tate, Mark W; Gruner, Sol M

2009-06-01

292

[Local injection of BRM-activated killer cells into an abdominal wall tumor].  

PubMed

Based on the concept of living with cancer, wherein the goal is to help patients with highly advanced solid cancers maintain a high quality of life(QOL)without adverse events and drug resistance, we developed a new immunocyte therapy based on BRM-activated killer(BAK)cells, which are primarily CD56 positive lymphocytes. In a previous report, we documented the disappearance of liver metastases, as assessed by positron emission tomography-computed tomography(PET-CT), in patients with metastatic liver cancers into which BAK immunocytes had been administered via injection into the hepatic artery. Herein, upon the patient's request, we locally injected BAK lymphocytes into an abdominal tumor. In BAK therapy, 20 mL of peripheral blood are collected from a patient. Lymphocytes from this blood sample are subsequently activated and multiplied with immobilized anti-CD3 antibodies and IL-2 and are cultured for 2 weeks with E(bina)and serum-free ALys media to yield approximately 10 billion autologous lymphocytes. On the final day of incubation, the lymphocytes are treated with 1,000 units/mL of interferon(IFN)-a for 15 minutes to enhance their therapeutic killing effects. During the second week, approximately 10 billion isolated autologous lymphocytes are suspended in 200 mL of Ringer's solution and are then drip-infused into the patient over a period of 1 hour. We injected approximately 10 billion BAK lymphocytes suspended in 50 mL of Ringer's solution into a 2-cm abdominal tumor in a single 60-year-old woman under ultrasonography guidance. This procedure was repeated every 3 weeks. After the third administration, we collected a biopsy specimen and examined it using PAS staining and microscopy. The 3 separate local injections of approximately 10 billion activated autologous lymphocytes each, primarily CD56 positive cells, into the tumor led to tumor fragmentation, leaving approximately 10 lymphocytes surrounding each cancer cell. These results suggest that BAK therapy is efficacious and show that locally administered BAK lymphocytes can reach cancer tissues and effectively kill cancer cells. PMID:24231704

Ebina, Takusaburo

2013-11-01

293

[Assessment of physical frame-based abdominal thickness estimation by evaluating conditions with fuzzy control: automatic exposure control (AEC) in diagnostic X-ray apparatus].  

PubMed

In digital X-ray photography of the abdomen and lumbar vertebrae, the automatic exposure control(AEC)system installed in the radiographic stand is essential for imaging at an appropriate dose. The AEC system has been used in many medical facilities. As patient size needs to be adapted, currently available AEC systems are equipped with a mechanism that enables an increase/decrease, by stages of 7-9, in AEC for X-ray dose. Adjustment of this function, however, depends largely on the radiologist's experience, as such X-ray dose control is lacking in reproducibility and quantification. We performed fuzzy reasoning using a measure of obesity(body-mass index: BMI)that was determined from the patient's height and body weight and estimated his/her abdominal thickness. On the basis of this estimated value, we established a methodology to define the conditions for X-ray photography of abdominal thickness in the area of increased patient thickness. We speculated that this methodology might provide better reproducibility and quantification for X-ray dose control in the area of increased patient thickness than the conventional AEC system. PMID:17510523

Kondo, Yuji

2007-04-20

294

Calcium distribution in the vessel wall and intima-media thickness of the human carotid arteries.  

PubMed

Increased common carotid artery (CCA) intima-media thickness (IMT) measured by B-mode ultrasound is an early marker of the atherosclerotic process. Arterial calcification is not clearly understood. Using the particle-induced X-ray emission (PIXE) method, we have looked for the location in the artery wall where calcium accumulated in the early phase of atherosclerosis. Twelve segments of CCAs of deceased stroke patients were investigated. In-vivo, carotid duplex ultrasound was performed with bilateral CCA IMT measurement at plaque-free sections. During autopsy, segments of carotid arteries were collected and filled under pressure with a stained histologic embedding material. The frozen arteries were cut into 60-microm-thick slices. Calcium distribution maps from the segments of arteries were determined by PIXE method. IMT measured by ultrasound and calcium distribution maps measured by PIXE were compared. In our cross-sectional study, using the PIXE analysis and ultrasound images, we could demonstrate early calcium accumulation in the media layer. Our results have also shown a significant relationship between calcium content of distributional maps measured by PIXE analysis and corresponding IMT on B-mode ultrasound images of human CCAs. PMID:17466442

Magyar, Mária Tünde; Szikszai, Zita; Kertész, Zsófia; Molnár, Sándor; Uzonyi, Imre; Szíki, Gusztáv Aron; Csiba, László

2007-08-01

295

Development of Thick B4C Coatings for the First Wall of W7-X  

NASA Astrophysics Data System (ADS)

For the actively cooled first wall panels of the W7-X stellarator under construction at Greifswald, Germany, boron carbide (B4C) coatings with a thickness up to 500 ?m are being developed as plasma facing surface on the stainless steel component. Different coating technologies (vacuum plasma spray (VPS), atmospherical plasma spray (APS)) are investigated. Characterisation of the coatings comprises metallo"graphic and SEM investigations, impurity determination and measurement of the thermal conductivity, characterisation of the sputtering behaviour and the behaviour under plasma exposure. First in-pile-tests in the tokamak TEXTOR-94 at the Research Centre Juelich have been performed. 10 poloidal limiter elements and 5 test limiters made of copper with a 170 ?m thick B4C VPS coating were exposed to plasma discharges with ohmic and additional heating. By varying the limiter positions and plasma density, different loading conditions were imposed. After exposure, the test limiters were removed for further analyses. First results showed the formation of small craters in the coating, probably due to arcing. Although melting occurred within a limited zone around the craters, the coatings did not detach from the substrate or show severe cracking outside the molten area.

Kötterl, S.; Bolt, H.; Greuner, H.; Huber, A.; Linke, J.; Mayer, M.; Pospieszczyk, A.; Renner, H.; Roth, J.; Schweer, B.; Sergienko, G.; Valenza, D.

296

Myositis ossificans in the right inferior thoracic wall as an unusual cause of lower thoracic-upper abdominal pain: report of a case.  

PubMed

We report a case of thoracic wall myositis ossificans (MO) located anterior to the ninth rib, causing right lower thoracic-upper abdominal pain. The diagnosis was based on the findings of ultrasonography (US) and computed tomography (CT). Numerous disorders can be included in the differential diagnosis of right lower thoracic-upper abdominal pain, so we must first establish if the pain is somatic or visceral in origin. Somatic pain in this region can be caused by traumatic muscle pain, overuse myalgia, costochondritis, or thoracic wall malignancies. Although rare, MO should also be considered in the differential diagnosis of pain and thoracic wall masses in this region. As the calcifications may not be seen on a plain chest X-ray in the early course of this condition, superficial tissue US or CT should be performed to establish the diagnosis. PMID:18820877

Ergun, Tarkan; Lakadamyali, Hatice; Lakadamyali, Huseyin; Gokay, Ertan

2008-01-01

297

Construction and validation of a questionnaire distinguishing a chronic abdominal wall pain syndrome from irritable bowel syndrome  

PubMed Central

Objective The irritable bowel syndrome (IBS) population is heterogeneous, harbouring a variety of abdominal symptoms. Therefore, IBS is often termed a ‘diagnosis of exclusion’. Chronic abdominal wall pain (CAWP) is a poorly recognized entity, frequently caused by the anterior cutaneous nerve entrapment syndrome (ACNES). Some patients may be misdiagnosed because IBS and CAWP share symptoms. Aim of this study was to construct and validate a questionnaire to distinguish patients with CAWP (including ACNES) patients with IBS. Design A questionnaire was designed of 17 ACNES characteristic items obtained from ACNES patients (n=33) and expert opinion of two specialized surgeons. Eleven IBS-related items (‘Rome III’ criteria) were added leading to a questionnaire containing 28 items. This was validated in a ‘gold standard’ ACNES group (successfully operated ACNES patients, n=68) and a ‘prospective’ IBS group (n=64) as well as in a ‘prospective’ ACNES group (n=47). Distinctive power of individual items was analyzed by ?2. Reliability was tested with Crohnbach's ?. ROC curve was used to determine cut-off values. Results Eighteen of 28 items were significantly distinctive (p<0.01) between ACNES and IBS patients leading to an 18-point ACNES score with good internal consistency (?=0.85). Cut-off value of 10 points resulted in 94% sensitivity, 92% specificity and areas under the curve (AUC) of 0.98. Evaluation of the prospective ACNES group led to 85% sensitivity, 92% specificity and AUC 0.95 indicating high discriminative properties of the questionnaire. Conclusions This novel questionnaire may be useful and valid as a simple tool distinguishing patients harbouring a CAWP syndrome from those having IBS.

van Assen, Tijmen; Boelens, Oliver B; Kamphuis, Jan T; Scheltinga, Marc R; Roumen, Rudi M

2012-01-01

298

Indications and Outcomes of the Components Separation Technique in the Repair of Complex Abdominal Wall Hernias: Experience From the Cambridge Plastic Surgery Department  

PubMed Central

Objectives: The components separation technique (CST) is a widely described abdominal wall reconstructive technique. There have, however, been no UK reports of its use, prompting the present review. Methods: Between 2008 and 2012, 13 patients who underwent this procedure by a single plastic surgeon (C.M.M.) were retrospectively evaluated. The indications, operative details, and clinical outcomes were recorded. Results: There were 7 women and 6 men in the series with a mean age of 53 years (range: 30-80). Patients were referred from a variety of specialties, often as a last resort. The commonest indication for CST was herniation following abdominal surgery. All operations except 1 were jointly performed with general surgeons (for bowel resection, stoma reversal, and hernia dissection). The operations lasted a mean of 5 hours (range: 3-8 hours). There were no major intra- and postoperative problems, except in 1 patient who developed intra-abdominal compartment syndrome, secondary to massive hemorrhage. All patients were satisfied with the cosmetic improvement in their abdominal contours. None of the patients have developed a clinical recurrence after a mean follow-up of 16 months (range: 3-38 months). Conclusions: The components separation technique is an effective method of treating large recalcitrant hernias but appears to be underutilized in the United Kingdom. The management of large abdominal wall defects requires a multidisciplinary approach, with input across a variety of specialities. Liaison with plastic surgery teams should be encouraged at an early stage and the CST should be more widely considered when presented with seemingly intractable abdominal wall defects.

Adekunle, Shola; Pantelides, Nicholas M.; Hall, Nigel R.; Praseedom, Raaj; Malata, Charles M.

2013-01-01

299

Reconstruction of full-thickness chest wall defects using rectus abdominis musculocutaneous flap: A report of fifteen cases  

SciTech Connect

In 15 patients chest walls were excised because of recurrent breast cancer, radiation ulcer, or rib tumor. In most cases the full-thickness defect of the chest wall was about 10 x 10 cm. Reconstruction was performed using only a rectus abdominis musculocutaneous flap. No patient developed circulation problems in the flap or severe flail chest, and we had successful results in all our cases. These results show that the rectus abdominis musculocutaneous flap is quite effective and safe to use in the reconstruction of chest wall defects.

Miyamoto, Y.; Hattori, T.; Niimoto, M.; Toge, T. (Hiroshima Univ. School of Medicine (Japan))

1986-02-01

300

Reconstruction of large-size abdominal wall defect using biodegradable poly-p-dioxanone mesh: an experimental canine study  

PubMed Central

Background Reconstruction of large-size abdominal wall defect (AWDs) is a huge challenge faced in current surgical practice. In this study, we aimed to evaluate the effectiveness and safety of biodegradable poly-p-dioxanone (PDO) mesh for reconstructing large-size AWDs in an experimental canine model. Methods Eighteen experimental canines were randomly and equally divided into three groups, namely, a PDO group, a Marlex group and a control group (n = 6 each). Following the creation of a 6 cm × 5.5 cm AWD, PDO mesh and Marlex mesh were used to reconstruct the defect in the PDO and Marlex groups, respectively. The defect was closed using relaxation sutures alone in the control group. Animals were killed 24 weeks after surgery, and reconstruction outcomes were evaluated using radiography, histology and biomechanical testing. Results All animals except those in the control group survived the experiment. The PDO group showed no wound dehiscence, herniation or infection, whereas the animals in the Marlex group exhibited marked foreign body reactions. The PDO group had less intraabdominal adhesion than the Marlex group. As shown by radiography, histology and biomechanical testing, PDO mesh exhibited complete degradation and favorable biochemical strength at 24 weeks postsurgery. Conclusions PDO mesh implantation is an effective, safe treatment modality for reconstructing large-size AWDs.

2014-01-01

301

Utilization of a global data grid repository in CAD assessment of carotid wall thickness  

NASA Astrophysics Data System (ADS)

A CAD method of calculating wall thickness of carotid vessels addresses the time-consuming issue of using B-mode ultrasound as well as inter- and intra-observer variability in results. Upon selection of a region-of-interest and filtering of a series of ultrasound carotid images, the CAD is able to measure the geometry of the lumen and plaque surfaces using a least-square fitting of the active contours during systole and diastole. To evaluate the approach, ultrasound image sequences from 30 patients were submitted to the procedure. The images were stored on an international data grid repository that consists of three international sites: Image Processing and Informatics (IPI) Laboratory at University of Southern California, USA; InCor (Heart Institute) at Sao Paulo, Brazil, and Hong Kong Polytechnic University, Hong Kong. The three chosen sites are connected with high speed international networks including the Internet2, and the Brazilian National Research and Education Network (RNP2). The Data Grid was used to store, backup, and share the ultrasound images and analysis results, which provided a large-scale and a virtual data system. In order to study the variability between the automatic and manual definition of artery boundaries, the pooled mean and the standard deviation for the difference between measurements of lumen diameter were computed. The coefficient of variation and correlation were also calculated. For the studied population the difference between manual and automatic measurement of the lumen diameter (LD) and intima-media-thickness (IMT) were 0.12 +/-0.10 and 0.09+/- 0.06, respectively.

Gutierrez, Marco A.; Lee, Jasper; Zhou, Zheng; Pilon, Paulo E.; Lage, Silvia G.

2007-03-01

302

Cigarette smoking and airway wall thickness on CT scan in a multi-ethnic cohort: The MESA Lung Study  

PubMed Central

Background Autopsy studies show that smoking contributes to airway wall hyperplasia and narrowing of the airway lumen. Studies of smoking and airway measures on computed tomography (CT) scan are limited to case-control studies of measures that combine airway lumen and wall thickness. Objectives We hypothesized that cumulative cigarette smoking would be associated with increased airway wall thickness in a large, population-based cohort. Methods The Multi-Ethnic Study of Atherosclerosis enrolled participants age 45-84 years from the general population. Smoking history was assessed via standardized questionnaire items; current smoking was confirmed in half the cohort with cotinine. Airway lumen and wall thickness were measured in two dimensions in posterior basal segmental bronchi on cardiac-gated CT scans. Analyses were adjusted for age, gender, genetic ancestry, education, height, weight, asthma history, particulate matter, scanner type, and scanner current. Results Half of the 7,898 participants had smoked and 14% were current smokers. Pack-years of smoking were associated with thicker airway walls (mean increase 0.002 mm per ten pack-years [95% CI: 0.00002, 0.004] p=0.03). Current smoking was associated with narrower airway lumens (mean decrease ?0.11 mm [95% CI: ?0.2, ?0.02] p=0.02). There was no evidence that either association was modified by genetic ancestry, and findings persisted among participants without clinical disease. Conclusions Long-term cigarette smoking was associated with subclinical increases in wall thickness of sub-segmental airways whereas current smoking was associated with narrower airway lumen diameters. Smoking may contribute to airway wall thickening prior to the development of overt chronic obstructive pulmonary disease.

Donohue, Kathleen M.; Hoffman, Eric A.; Baumhauer, Heather; Guo, Junfeng; Budoff, Matthew; Austin, John H.M.; Kalhan, Ravi; Kawut, Steven; Tracy, Russell; Barr, R. Graham

2013-01-01

303

A new possibility of melt cooling in extrusion dies to prevent sagging-effects in thick-walled pipes  

NASA Astrophysics Data System (ADS)

One challenge in the extrusion process of thick-walled pipes is the cooling of the product. Besides the output of the extruder, the line speed is also limited by the efficiency of the cooling line. The cooling time increases according to the wall thickness of the pipe under otherwise equal process conditions. State of the art is the cooling of the outer surface in water tanks or spray-cool-tanks. In addition to that, it is possible to cool the inner surface by air that is sucked through the pipe. Despite these technologies it is problematic to cool down thick walled-products with the right speed. Especially thick-walled pipes show problems by cooling the layers in the middle of the wall. On the one hand an intensive cooling of the outer and inner surface of the pipe entail the formation of shrink holes in the middle of the pipe wall. On the other hand without a quick cooling the melt flow in circumferential direction because of the gravity takes place (sagging-effect). Because of this reason in the presented paper new possibilities of melt cooling in extrusion dies to prevent sagging-effects are given. An aimed cooling of the inbound melt layers inside the extrusion die could prevent the effect of melt flow in circumferential direction after the extrusion die, allows the specification of a specific temperature profile over the radius of the pipe wall and helps to reduce the melt temperature for rising mass throughputs and screw driving speeds of the extruder. It is also thinkable to influence the crystallization process and thereby the mechanical properties of the end-product by an aimed cooling of the inner pipe layers.

te Heesen, O.; Wortberg, J.

2014-05-01

304

Bobbin-Tool Friction-Stir Welding of Thick-Walled Aluminum Alloy Pressure Vessels  

SciTech Connect

It was desired to assemble thick-walled Al alloy 2219 pressure vessels by bobbin-tool friction-stir welding. To develop the welding-process, mechanical-property, and fitness-for-service information to support this effort, extensive friction-stir welding-parameter studies were conducted on 2.5 cm. and 3.8 cm. thick 2219 Al alloy plate. Starting conditions of the plate were the fully-heat-treated (-T62) and in the annealed (-O) conditions. The former condition was chosen with the intent of using the welds in either the 'as welded' condition or after a simple low-temperature aging treatment. Since preliminary stress-analyses showed that stresses in and near the welds would probably exceed the yield-strength of both 'as welded' and welded and aged weld-joints, a post-weld solution-treatment, quenching, and aging treatment was also examined. Once a suitable set of welding and post-weld heat-treatment parameters was established, the project divided into two parts. The first part concentrated on developing the necessary process information to be able to make defect-free friction-stir welds in 3.8 cm. thick Al alloy 2219 in the form of circumferential welds that would join two hemispherical forgings with a 102 cm. inside diameter. This necessitated going to a bobbin-tool welding-technique to simplify the tooling needed to react the large forces generated in friction-stir welding. The bobbin-tool technique was demonstrated on both flat-plates and plates that were bent to the curvature of the actual vessel. An additional issue was termination of the weld, i.e. closing out the hole left at the end of the weld by withdrawal of the friction-stir welding tool. This was accomplished by friction-plug welding a slightly-oversized Al alloy 2219 plug into the termination-hole, followed by machining the plug flush with both the inside and outside surfaces of the vessel. The second part of the project involved demonstrating that the welds were fit for the intended service. This involved determining the room-temperature tensile and elastic-plastic fracture-toughness properties of the bobbin-tool friction-stir welds after a post-weld solution-treatment, quenching, and aging heat-treatment. These mechanical properties were used to conduct fracture-mechanics analyses to determine critical flaw sizes. Phased-array and conventional ultrasonic non-destructive examination was used to demonstrate that no flaws that match or exceed the calculated critical flaw-sizes exist in or near the friction-stir welds.

Dalder, E C; Pastrnak, J W; Engel, J; Forrest, R S; Kokko, E; Ternan, K M; Waldron, D

2007-06-06

305

Dynamic Response of a Pulse-Heated, Thick-Walled, Hollow Sphere: Validation of Code Numerics  

SciTech Connect

Volumetric pulse heating of a thick-walled hollow sphere is numerically investigated. The primary objective is to validate a variety of LLNL 30 hydrocodes for modeling the dynamic behavior of fissile/fissionable metals subject to rapid ''fission-heating'' transients. The 30 codes tested include both DYNA3D and NIKE3D, as well as the ''ASCI'' code, ALE3D. The codes are compared ''head-to-head'' and are benchmarked against a 1D finite difference solution to the problem that is derived from basic principles. Three pulse-heating transients are examined with full-width-half-maximum pulse durations of 41{micro}s, 85{micro}s, and 140{micro}s, respectively. These three transients produce a significant range of dynamic responses in the thermo-elastic regime. We present results for dynamic radial displacements and stresses for each pulse, and also discuss which code features/options worked best for these types of calculations. In general, the code results are in excellent agreement for the simple system considered. Validation of code numerics in simple systems is a key first step toward future application of the codes in more complicated geometries (U).

Canaan, R.E.

2000-01-19

306

The interaction of moderately strong shock waves with thick perforated walls of low porosity  

NASA Technical Reports Server (NTRS)

A theoretical prediction is given of the flow through thick perforated walls of low porosity resulting from the impingement of a moderately strong traveling shock wave. The model was a flat plate positioned normal to the direction of the flow. Holes bored in the plate parallel to the direction of the flow provided nominal hole length-to-diameter ratios of 10:1 and an axial porosity of 25 percent of the flow channel cross section. The flow field behind the reflected shock wave was assumed to behave as a reservoir producing a quasi-steady duct flow through the model. Rayleigh and Fanno duct flow theoretical computations for each of three possible auxiliary wave patterns that can be associated with the transmitted shock (to satisfy contact surface compatibility) were used to provide bounding solutions as an alternative to the more complex influence coefficients method. Qualitative and quantitative behavior was verified in a 1.5- by 2.0-in. helium shock tube. High speed Schlieren photography, piezoelectric pressure-time histories, and electronic-counter wave speed measurements were used to assess the extent of correlation with the theoretical flow models. Reduced data indicated the adequacy of the bounding theory approach to predict wave phenomena and quantitative response.

Grant, D. J.

1972-01-01

307

Chest-Wall Thickness and Percent Thoracic Fat Estimation by B-Mode Ultrasound: System and Procedure Review.  

National Technical Information Service (NTIS)

Accurate measurement of chest wall thickness is necessary for estimation of lung burden of transuranic elements in humans. To achieve tis capability, the ORNL Whole Body Counter has acquired a B-mode ultrasonic imaging system for defining the structure wi...

C. D. Berger B. H. Lane M. R. Dunsmore

1983-01-01

308

A Data Mining Approach for Coronary Heart Disease Prediction using HRV Features and Carotid Arterial Wall Thickness  

Microsoft Academic Search

The main objective of our work has been to develop and then propose a new and unique methodology useful in developing the various features of heart rate variability (HRV) and carotid arterial wall thickness helpful in diagnosing cardiovascular disease. We also propose a suitable prediction model to enhance the reliability of medical examinations and treatments for cardiovascular disease. We analyzed

Heon Gyu Lee; Kiyong Noh; Keun Ho Ryu

2008-01-01

309

Small radial vibrations of layered, hyperelastic, spherical shells of arbitrary wall thickness subjected to finite, initial radial deformations  

Microsoft Academic Search

Small, radial vibrations of layered spherical shells of arbitrary wall thickness and subjected to initial external and\\/or internal pressure causing finite radial deformations are investigated. The material of each layer is assumed to be of neo-Hookean type. The governing equations of both the finitely deformed static state and the superposed secondary dynamical state which are obtained, respectively, by the theory

H. Evirgen; A. Ertepinar

1989-01-01

310

The preferential contraction ratios of transversus abdominis on the variations of knee angles during abdominal drawing-in maneuver in wall support standing.  

PubMed

The objective of this study was to determine appropriate knee angles for the abdominal drawing-in maneuver (ADIM) through evaluation of changes in contraction ratios of the abdominal muscles and activity of quadriceps muscle in relation to changes in knee angles occurring while the ADIM is performed in the wall support standing (WSS). 20 subjects performed the ADIM at different knee angles (0°, 20°, 40°, 60°) in random order, standing at a point 6 inches away from the wall with the spine maintained in the neutral position. The WSS with knee flexion at 20° showed significantly higher preferential contraction ratio (PCR) of transversus abdominis (TrA) compared to other positions (0°, 40°, 60°). Therefore, performing the ADIM in the WSS with knee flexion at 20° appears to be the most appropriate position for TrA PCR. PMID:24877045

Hwang, Young-In; Kim, Jwa-Jun; Park, Du-Jin

2014-04-01

311

The preferential contraction ratios of transversus abdominis on the variations of knee angles during abdominal drawing-in maneuver in wall support standing  

PubMed Central

The objective of this study was to determine appropriate knee angles for the abdominal drawing-in maneuver (ADIM) through evaluation of changes in contraction ratios of the abdominal muscles and activity of quadriceps muscle in relation to changes in knee angles occurring while the ADIM is performed in the wall support standing (WSS). 20 subjects performed the ADIM at different knee angles (0°, 20°, 40°, 60°) in random order, standing at a point 6 inches away from the wall with the spine maintained in the neutral position. The WSS with knee flexion at 20° showed significantly higher preferential contraction ratio (PCR) of transversus abdominis (TrA) compared to other positions (0°, 40°, 60°). Therefore, performing the ADIM in the WSS with knee flexion at 20° appears to be the most appropriate position for TrA PCR.

Hwang, Young-In; Kim, Jwa-Jun; Park, Du-Jin

2014-01-01

312

Correlations of electrocardiography and echocardiography in determination of left ventricular wall thickness: Study of apparently normal subjects.  

PubMed

To examine the usefulness of the surface electrocardiogram in predicting left ventricular wall thickness as determined with echocardiography, standard echocardiograms, electrocardiograms and Frank lead vectorcardiograms were obtained in 30 volunteers. End-diastolic thickness of the interventricular septum and free posterior wall was measured from the echocardiogram and compared with the sum of the S wave in lead V1 plus the R wave in lead V6 (VS1+R6) and the magnitude of the Frank lead vector (Vf), a scalar dunction obtained from a simple analog device. The maximum of Vf, the summated vector (Vf), was highly correlated with VS1+R6 (r=0.84). There was significant correlation between the summated vector and VS1+R6 and the thickness of the interventricular septum (IVS) (r=0.73 and 0.66, respectively). The best least mean square fit for the population was Vf=1.7 IVS-0.39. There was no significant correlation between these variables and the end-diastolic thickness of the posterior wall. Volunteers who were athletically inclined or were joggers tended to have larger summated vector values and evidence of symmetric or asymmetric left ventricular hypertrophy in the echocardiogram. It therefore appears that the thickness of the interventricular septum has a greater influence on the summated vector and VS1+R6 that the echocardiographically assessed thickness of the free posterior wall of the left ventricle. The implications of these findings in the light of recent reports about the incidence of echocardiographically diagnosed left ventricular hypertrophy are discussed. PMID:138358

Bahler, A S; Teichholz, L E; Gorlin, R; Herman, M V

1977-02-01

313

CT of the Extrahepatic Bile Ducts: Wall Thickness and Contrast Enhancement in Normal and Abnormal Ducts  

Microsoft Academic Search

duct wall on CT, and to develop a differential diagnosis for thickening of the duct wall. Routine CT examinations of 100 patients without biliary disease were evaluated pro- spectively. The common hepatic duct and common bile duct could be visualized in 66% and 82% of cases, respectively; the walls of these ducts could be separately discerned in 59% and 52%.

Scott J. Schulte; Richard L. Baron; Sharlene A. Teefey; Charles A. Rohrmann; Patrick C. Freeny; William P. Shuman; Michael A. Foster

314

Adverse effect of increased left ventricular wall thickness on five year outcomes of patients with negative dobutamine stress  

PubMed Central

Background To determine if patients without dobutamine induced left ventricular wall motion abnormalities (WMA) but an increased LV end-diastolic wall thickness (EDWT) exhibit a favorable cardiac prognosis. Results Between 1999 and 2001, 175 patients underwent a dobutamine stress cardiovascular magnetic resonance (DCMR) procedure utilizing gradient-echo cines. Participants had a LV ejection fraction >55% without evidence of an inducible WMA during peak dobutamine/atropine stress. After an average of 5.5 years, all participants were contacted and medical records were reviewed to determine the post-DCMR occurrence of cardiac death, myocardial infarction (MI), and unstable angina (USA) or congestive heart failure (CHF) warranting hospitalization. In a multivariate analysis, that took into account Framingham and other risk factors associated with cardiac events, a cine gradient-echo derived LV EDWT ?12 mm was associated independently with an increase in cardiac death and MI (HR 6.0, p = 0.0016), and the combined end point of MI, cardiac death, and USA or CHF warranting hospitalization (HR 3.0, p = 0.0005). Conclusion Similar to echocardiography, CMR measures of increased LV wall thickness should be considered a risk factor for cardiac events in individuals receiving negative reports of inducible ischemia after dobutamine stress. Additional prognostic studies of the importance of LV wall thickness and mass measured with steady-state free precession techniques are warranted.

Walsh, Thomas F; Dall'Armellina, Erica; Chughtai, Haroon; Morgan, Timothy M; Ntim, William; Link, Kerry M; Hamilton, Craig A; Kitzman, Dalane W; Hundley, W Gregory

2009-01-01

315

Sarcocystis sinensis is the most prevalent thick-walled Sarcocystis species in beef on sale for consumers in Germany.  

PubMed

Bovines are intermediate hosts of Sarcocystis cruzi, Sarcocystis hirsuta, and Sarcocystis hominis, which use canids, felids, or primates as definitive hosts, respectively. Cattle represent also intermediate hosts of Sarcocystis sinensis, but the definitive hosts of this parasite are not yet known. Sarcocystosis in cattle is frequently asymptomatic. The infection is characterized by the presence of thin-walled (S. cruzi) or thick-walled muscle cysts or sarcocysts (S. hominis, S. sinensis, and S. hirsuta). Recent reports suggest high prevalence of the zoonotic S. hominis in beef in Europe. We therefore aimed at differentiating Sarcocystis spp. in beef offered to consumers in Germany using molecular and microscopical methods, focusing on those species producing thick-walled sarcocysts. A total of 257 beef samples were obtained from different butcheries and supermarkets in Germany and processed by conventional and multiplex real-time PCR. In addition, 130 of these samples were processed by light microscopy and in 24.6 % thick-walled cysts were detected. Transmission electron microscopical analysis of six of these samples revealed an ultrastructural cyst wall pattern compatible with S. sinensis in five samples and with S. hominis in one sample. PCR-amplified 18S ribosomal DNA (rDNA) fragments of 28 individual thick-walled cysts were sequenced, and sequence identities of ?98 % with S. sinensis (n?=?22), S. hominis (n?=?5) and S. hirsuta (n?=?1) were observed. Moreover, nine Sarcocystis sp. 18S rDNA full length gene sequences were obtained, five of S. sinensis, three of S. hominis, and one of S. hirsuta. Out of all samples (n?=?257), 174 (67.7 %) tested positive by conventional PCR and 179 (69.6 %) by multiplex real-time PCR for Sarcocystis spp. Regarding individual species, 134 (52 %), 95 (37 %), 17 (6.6 %), and 16 (6.2 %) were positive for S. cruzi, S. sinensis, S. hirsuta, and S. hominis, respectively. In conclusion, S. sinensis is the most prevalent thick-walled Sarcocystis species in beef offered for consumption in Germany. Further studies are needed to identify the final host of S. sinensis as well as the potential role of this protozoan as a differential diagnosis to the zoonotic species S. hominis. PMID:24700022

Moré, G; Pantchev, A; Skuballa, J; Langenmayer, M C; Maksimov, P; Conraths, F J; Venturini, M C; Schares, G

2014-06-01

316

The mechanism of instability and localized reaction in the explosively driven collapse of thick walled Ni-Al laminate cylinders  

NASA Astrophysics Data System (ADS)

Thick-walled cylinders constructed from alternating concentric layers of Ni and Al foils were explosively collapsed. The prevalent mode of the high strain, high strain rate plastic deformation was the cooperative buckling of the foils originating in the interior layers. This phenomenon was reproduced in numerical simulations. Its mechanism is qualitatively different than that of shear localization seen in all previously investigated homogeneous solid and granular materials and from the independent buckling of single thin-walled cylinders. Localized chemical reactions were observed in the apex areas of the Ni foils, consistent with the localization of temperature due to high strain plastic deformation.

Chiu, P. H.; Olney, K. L.; Higgins, A.; Serge, M.; Benson, D. J.; Nesterenko, V. F.

2013-06-01

317

Biometric estimation of chest wall thickness of female radiation workers as an aid in in-vivo detection of the actinides  

SciTech Connect

An equation was derived to estimate female chest wall thickness from a series of biometric measurements. This technique will result in improved performance for actinide detection in females by accounting for variations in chest wall thickness in derivation of calibration factors.

Lane, B.H.; Berger, C.D.

1983-01-01

318

Wound Complications of the Retroperitoneal Approach for the Abdominal Aortic Aneurysm Repair--An Evaluation of Abdominal Bulge Formation--  

PubMed Central

Objective: To evaluate the incidence of wound complications after the retroperitoneal approach for abdominal aortic aneurysm (AAA) repair, and to ascertain the cause of abdominal bulge (AB). Subjects and Methods: Forty-three patients with AAA repair via the retroperitoneal space were retrospectively investigated. Wound complications and their incidence were studied by chart review. The thickness of the abdominal wall muscle was measured by follow-up computed tomography films. Compound muscle action potentials (CMAPs) of the abdominal rectus muscle were examined for three bulge patients and three non-bulge patients. Results: Wound hypoesthesia (30%), wound numbness (21%), AB (7%), and wound pain (2%) were found in these patients. The thickness of the abdominal wall muscle was reduced in the incision side. CMAP of abdominal rectus muscle in the incision side disappeared only in AB patients. Conclusions: (1) Wound hypoesthesia and numbness displayed a high incidence. (2) Atrophy of the abdominal wall muscle in the incision side was found in these patients. (3) The cause of AB is considered to be muscle atrophy induced by denervation injury of an 11th intercostal nerve. (4) To avoid an eleventh intercostal nerve injury must be deemed the most effective method for preventing AB.

2014-01-01

319

Model and numerical simulation for the evolution of residual wall thickness in Water-Assisted Injection Molding  

NASA Astrophysics Data System (ADS)

The motion of water-melt interface confined in horizontal circular tubes during Water-Assisted Injection Molding (WAIM) has been studied both theoretically and experimentally. Of particular interest is the determination of residual melt film thickness on the walls. The reduced governing equations for viscous compressible non-Newtonian polymer melt during the second penetration in WAIM were established using dimensionless method. A formula used to calculate the second penetrating velocity was derived based on mathematical inference and mechanical principle. Experiments was conducted to measure the displacement of the water-melt interface as a function of the melt temperature, water pressure. The experimental results indicate the first penetration theory is not accurate in predicting residual wall thickness and the combined first and second penetration theories can improve the accuracy significantly.

Li, Qian; Cao, Wei; Zhang, Shixun; Shen, Changyu

2010-06-01

320

An experimental investigation into the buckling of cylindrical shells of variable-wall thickness under radial external pressure  

Microsoft Academic Search

Cylindrical shells, with wall thickness-to-diameter ratios varying in steps from 1:2000 to 1:500 are used in large floating-roof storage tanks, where buckling under partial vacuum is a potential risk. To examine the validity of several methods of analysis, aluminum models with a nominal diameter of 150 mm were tested. Some models exhibited a sudden buckling, at the pressure predicted by

Z. Malik; J. Morton; C. Ruiz

1979-01-01

321

Low Plasma Lycopene Concentration Is Associated With Increased Intima-Media Thickness of the Carotid Artery Wall  

Microsoft Academic Search

Although a number of epidemiological studies have evaluated the association between b-carotene and the risk of cardiovascular diseases, there has been little research on the role of lycopene, an acyclic form of b-carotene, with regard to the risk of cardiovascular disease. We investigated the relationship between plasma concentrations of lycopene and intima-media thickness of the common carotid artery wall (CCA-IMT)

Tiina Rissanen; Sari Voutilainen; Kristiina Nyyssönen; Riitta Salonen; Jukka T. Salonen

2010-01-01

322

Model and numerical simulation for the evolution of residual wall thickness in Water-Assisted Injection Molding  

Microsoft Academic Search

The motion of water-melt interface confined in horizontal circular tubes during Water-Assisted Injection Molding (WAIM) has been studied both theoretically and experimentally. Of particular interest is the determination of residual melt film thickness on the walls. The reduced governing equations for viscous compressible non-Newtonian polymer melt during the second penetration in WAIM were established using dimensionless method. A formula used

Qian Li; Wei Cao; Shixun Zhang; Changyu Shen

2010-01-01

323

Evaluation of a canine small intestinal submucosal xenograft and polypropylene mesh as bioscaffolds in an abdominal full-thickness resection model of growing rats  

PubMed Central

We evaluated the biological scaffold properties of canine small intestinal submucosa (SIS) compared to a those of polypropylene mesh in growing rats with full-thickness abdominal defects. SIS is used to repair musculoskeletal tissue while promoting cell migration and supporting tissue regeneration. Polypropylene mesh is a non-resorbable synthetic material that can endure mechanical tension. Canine SIS was obtained from donor German shepherds, and its porous collagen fiber structure was identified using scanning electron microscopy (SEM). A 2.50-cm2 section of canine SIS (SIS group) or mesh (mesh group) was implanted in Sprague-Dawley rats. At 1, 2, 4, 12, and 24 weeks after surgery, the implants were histopathologically examined and tensile load was tested. One month after surgery, CD68+ macrophage numbers in the SIS group were increased, but the number of CD8+ T cells in this group declined more rapidly than that in rats treated with the mesh. In the SIS group, few adhesions and well-developed autologous abdominal muscle infiltration into the SIS collagen fibers were observed. No significant differences in the tensile load test results were found between the SIS and mesh groups at 24 weeks. Canine SIS may therefore be a suitable replacement for artificial biological scaffolds in small animals.

Lee, A-Jin; Lee, Sung-Ho; Chung, Wook-Hun; Kim, Dae-Hyun; Chung, Dai-Jung; Do, Sun Hee

2013-01-01

324

Investigation of Adiabatic Shear Bands in Thick-Walled Cylinders Collapsed by Electro-Magnetic Driving Forces  

NASA Astrophysics Data System (ADS)

The Thick-Walled Cylinder technique, reported in the literature, employs an explosive cylinder to create the driving force, collapsing the cylindrical sample. This experimental set-up has been established as a controlled and repeatable technique to create and study multiple adiabatic shear bands. Searching to establish a simpler experimental platform to perform large sets of experiments, we have designed an Electro-Magnetic (EM) set-up for the collapse of thick walled cylinders. The EM setup is based on a pulsed current generator using a capacitor bank system. The specimen is an assembly of coaxial cylinders, where the inner and outer cylinders, each attached to an opposite pole, are short-circuited. Upon discharge, a high current flows through the cylinders, in opposite directions, creating repulsive magnetic forces between them. This work presents the design procedure of the specimens using numerical simulations as well as some results for SS304L thick-walled specimens, using this setup. The spatial distribution of the multiple adiabatic shear bands in these experiments is in good agreement with that reported in the literature for the explosive driven experiments with SS304L specimens. Our numerical simulations show good agreement with the experimental results for both global behaviour and shear band distribution.

Lovinger, Z.; Rikanati, A.; Rittel, D.; Rosenberg, Z.

2009-12-01

325

Differences in cell wall thickness between resistant and nonresistant strains of Mycobacterium tuberculosis: using transmission electron microscopy.  

PubMed

The ultrastructure of the cell wall of extensively drug-resistant (XDR), multidrug-resistant (MDR) and susceptible tuberculosis (TB) bacilli was viewed under transmission electron microscopy (TEM). Under the TEM, marked differences were observed in the thickness of their cell wall: 20.2 +/-1.5 and 17.1 +/-1.03 nm for the XDR and MDR TB bacilli, respectively, and 15.6 +/- 1.3 nm for the susceptible isolates (p < 0.05). In MDR bacilli, thickening of the cell wall was observed in the intermediate electron-transparent layer (ETL) and outer electron-opaque layer, whereas in XDR TB cells the basal peptidoglycan layer was denser and almost fused with the ETL. Five to seven percent of XDR TB bacilli had the appearance of the stationary phase with cell wall thickness ranging from 21 to 26 nm (p < 0.001). Information provided in this study is of significant importance in terms of drug selection for effective treatment of resistant strains. PMID:19556787

Velayati, Ali Akbar; Farnia, Parissa; Ibrahim, Tengku Azmi; Haroun, Rafiuz Zaman; Kuan, Ho Oi; Ghanavi, Jalaledin; Farnia, Poopak; Kabarei, Ali Naghee; Tabarsi, Payam; Omar, Abdul Rahman; Varahram, Mohammad; Masjedi, Mohammad Reza

2009-01-01

326

Totally transanal LESS pull-through colectomy: a novel approach for avoiding abdominal wall incision in children with long-segment intestinal aganglionosis.  

PubMed

Abstract Introduction: Minimally invasive surgery in children with long-segment intestinal aganglionosis aims to reduce the number of abdominal wall incisions. Conventional laparoscopic and laparoendoscopic single-site (LESS) surgeries fulfill this goal. In children, natural orifice translumenal endoscopic surgery (NOTES™; American Society for Gastrointestinal Endoscopy [Oak Brook, IL] and Society for American Gastrointestinal and Endoscopic Surgeons [Los Angeles, CA]) has been limited because of fear of access site complications. We present a novel technique of totally transanal LESS pull-through colectomy (TLPC), avoiding abdominal wall incision, which combines LESS technology and the NOTES approach. Subjects and Methods: Two boys and one girl (2.5 months, 6 months, and 5 years of age, respectively) with sigmoid and transverse colon aganglionosis underwent surgery. The TLPC procedure consisted of an endorectal technique with submucosal dissection starting 1?cm orally from the dentate line to above the peritoneal reflection, where the rectal muscle was divided circumferentially. After ligation of the rectal mucosa, the proximal bowel was replaced into the abdominal cavity, and a TriPort(®) (Olympus Surgical Technologies Europe, Hamburg, Germany) was introduced transanally. Mesenterial resection of the aganglionic bowel was accomplished via transanal LESS until the normoganglionic colon segment was reached and pulled down to the site of anastomosis. After removal of the port, a conventional pull-through procedure was performed. Results: All children displayed normal bowel movements and were complication-free during the follow-up period of up to 7 months. Conclusions: TLPC combines the minimally invasive LESS surgery with the scarless concept of NOTES and allows resection of long-segment aganglionosis without abdominal incision. TLPC is a safe, effective, and feasible surgical procedure in children with long-segment intestinal aganglionosis. PMID:23402288

Vahdad, Mohammad Reza; Foroutan, Ali; Najafi, Sultan Mohsen; Cernaianu, Grigore; Tröbs, Ralf-Bodo; Banani, Seyed Abbas; Foroutan, Hamid Reza

2013-03-01

327

Recommendations for protecting against failure by brittle fracture: Category II and III ferritic steel shipping containers with wall thickness greater than four inches  

SciTech Connect

This report provides criteria for selecting ferritic steels that would prevent brittle fracture in Category II and III shipping containers with wall thickness greater than 4 inches. These methods are extensions of those previously used for Category II and III containers less than 4 inches thick and Category I containers more than 4 inches thick.

Schwartz, M.W.; Fischer, L.E. [Lawrence Livermore National Lab., CA (United States)

1996-08-01

328

Riser Difference Evaluation from Ultrasonic Wall Thickness Inspection of Thirteen Double-Shell Tanks  

SciTech Connect

PNNL has performed an analysis of ultrasonic thickness measurements taken on Hanford's double-shell tanks (DSTs) approximately eight years apart. The analysis was performed to determine whether significant differences exist between ultrasonic thickness measurements made in two opposite risers in Hanford DSTs that have been examined twice.

Weier, Dennis R.; Pardini, Allan F.

2010-03-15

329

Association between Plasma Angiopoietin-Like Protein 3 and Arterial Wall Thickness in Healthy Subjects  

Microsoft Academic Search

Background: Angiopoietin-like protein 3 (ANGPTL3) is a liver-derived plasma protein that modulates plasma triglyceride clearance, angiogenesis and atherosclerosis in experimental models. So far, no study has examined its role in atherosclerosis in human subjects. We evaluated the possible association between plasma ANGPTL3 level and carotid artery intima-media thickness (CA-IMT) and femoral artery intima-media thickness (FA-IMT) in healthy human subjects. Methods:

Sawako Hatsuda; Tetsuo Shoji; Kayo Shinohara; Eiji Kimoto; Katsuhito Mori; Shinya Fukumoto; Hidenori Koyama; Masanori Emoto; Yoshiki Nishizawa

2007-01-01

330

Simulation Analysis on Backward Spinning of Extra thin-walled Shielding Can with High Ratio of Diameter/Thickness  

NASA Astrophysics Data System (ADS)

A new FEM simplified elastoplastic mechanical model is constructed for the backward spinning process of the extra thin-walled shielding can with high ratio of diameter/thickness. The feed mode of the roller adopts the pulsing schedule, which is closer to the actual working condition. Additionally, this new FEM simplified model is significant saving in computing time. In this paper, the metal plastic flow field and the distributions of stress and strain of the deformation zone are studied by the large-scale FEM analysis software MSC.Marc. The causes of the defects of the workpieces are interpreted and the dividing point of the flowing direction of the metal is obtained, accordingly. And the theoretical guidance for the actual processing of the extra thin-walled shield can with high ratio of diameter/thickness is provided. The C-276 shielding can with 0.42 mm thickness and 561.5 mm diameter is successfully trial-produced. It proves that above mentioned analysis is reasonable.

Li, Xinhe; He, Xiahui; Yang, Xinquan

2011-08-01

331

Abdominal hernias: Radiological features  

PubMed Central

Abdominal wall hernias are common diseases of the abdomen with a global incidence approximately 4%-5%. They are distinguished in external, diaphragmatic and internal hernias on the basis of their localisation. Groin hernias are the most common with a prevalence of 75%, followed by femoral (15%) and umbilical (8%). There is a higher prevalence in males (M:F, 8:1). Diagnosis is usually made on physical examination. However, clinical diagnosis may be difficult, especially in patients with obesity, pain or abdominal wall scarring. In these cases, abdominal imaging may be the first clue to the correct diagnosis and to confirm suspected complications. Different imaging modalities are used: conventional radiographs or barium studies, ultrasonography and Computed Tomography. Imaging modalities can aid in the differential diagnosis of palpable abdominal wall masses and can help to define hernial contents such as fatty tissue, bowel, other organs or fluid. This work focuses on the main radiological findings of abdominal herniations.

Lassandro, Francesco; Iasiello, Francesca; Pizza, Nunzia Luisa; Valente, Tullio; Stefano, Maria Luisa Mangoni di Santo; Grassi, Roberto; Muto, Roberto

2011-01-01

332

Dynamics of domain walls in magnetically multiaxial films in the thickness range corresponding to the Bloch-Néel transformations of the structure  

NASA Astrophysics Data System (ADS)

The numerical minimization of the total energy functional and the solution of the nonlinear Landau-Lifshitz equation have been performed exactly taking into account the fundamental (including dipole-dipole) interactions in terms of the two-dimensional magnetization distribution. The equilibrium structure, energy, mobility, and scenario of the dynamic transformation of the domain walls (in their non- steady-state motion) have been determined as a function of the film thickness b and external magnetic field H for two different ((010) and (110)) orientations of the surfaces of magnetically triaxial films. The range of film thicknesses, including the thickness b = b N, for which the Néel domain walls can be transformed into the Bloch domain walls, has been investigated. The phenomena of anisotropy of the domain-wall energy, the domain-wall mobility, and the period of dynamic transformations of the domain walls have been analyzed as a function of the film thickness b and external magnetic field H. The range of film thicknesses has been determined, in which the non-steady-state motion of the Néel domain walls is accompanied by the creation and annihilation of vortex-like structures despite the one-dimensional character of the magnetization distribution in these walls.

Filippov, B. N.

2012-12-01

333

The gender-specific chest wall thickness prediction equations for routine measurements of 239Pu and 241Am within the lungs using HPGe detectors.  

PubMed

The current chest wall thickness prediction equation is not applicable to use in routine lung counting measurements for detection of low energy photons (17--60 keV) within the lungs of male and female subjects. The current chest wall thickness prediction equation was derived for the NaI-CsI "phoswich" detection system, which is not the routine detection system in use; the subject position was supine, which is not the routine position; the equation did not account for the intercostal tissue thicknesses of muscle and adipose which significantly attenuate low energy photons (17--60keV); it was derived from male subjects only and is used to predict the chest wall thickness of female subjects for whom it is not applicable. The current chest wall thickness prediction equation yields unacceptable percent errors in the HPGe detection efficiency calibration for 239Pu and 241Am (17- and 59.5-keV photons, respectively) relative to the gender-specific HPGe chest wall thickness prediction equations of this paper (+284% to --73% for 239Pu; (+)42% to --39% for 241Am). As a result, use of the current chest wall thickness prediction equation yields unacceptable percent errors (proportional in magnitude to the percent errors in the detection efficiency calibration) in the calculation of the minimum detectable activity (Bq) or in an initial assessment of a radioactive contamination exposure detected by a routine lung count measurement. PMID:8609026

Vickers, L R

1996-03-01

334

Airway Wall Thickness Assessed Using Computed Tomography and Optical Coherence Tomography  

Microsoft Academic Search

Rationale: Computed tomography (CT) has been shown to reliably measure the airway wall dimensions of medium to large airways. Optical coherence tomography (OCT) is a promising new micron- scale resolution imaging technique that can image small airways 2 mm in diameter or less. Objectives: To correlate OCT measurements of airway dimensions with measurements assessed using CT scans and lung function.

Harvey O. Coxson; Brendan Quiney; Don D. Sin; Li Xing; Annette M. McWilliams; John R. Mayo

2008-01-01

335

Formation of Rhamnogalacturonan II-Borate Dimer in Pectin Determines Cell Wall Thickness of Pumpkin Tissue1  

PubMed Central

Boron (B) deficiency results in inhibition of pumpkin (Cucurbia moschata Duchesne) growth that is accompanied by swelling of the cell walls. Monomeric rhamnogalacturonan II (mRG-II) accounted for 80% to 90% of the total RG-II in B-deficient walls, whereas the borate ester cross-linked RG-II dimer (dRG-II-B) accounted for more than 80% of the RG-II in control plants. The results of glycosyl residue and glycosyl linkage composition analyses of the RG-II from control and B-deficient plants were similar. Thus, B deficiency does not alter the primary structure of RG-II. The addition of 10B-enriched boric acid to B-deficient plants resulted within 5 h in the conversion of mRG-II to dRG-II-10B. The wall thickness of the 10B-treated plants and control plants was similar. The formation and possible functions of a borate ester cross-linked RG-II in the cell walls are discussed.

Ishii, Tadashi; Matsunaga, Toshiro; Hayashi, Noriko

2001-01-01

336

Probing the magnetization reversal process of permalloy nano-rings with high wall height-to-thickness ratios  

NASA Astrophysics Data System (ADS)

We report a study of magnetization reversal process on a tall magnetic nano-ring with a wall height-to-thickness ratio of up to 21. Samples in a hexagonal lattice pattern of ring array with an outer/inner diameter of 300/260 nm and a ring height of 420 nm are fabricated using electron beam lithography in conjunction with an ion beam etching technique. A longitudinal magneto-optical Kerr effect (MOKE) measurement reveals that meta-stable states exist during the magnetization reversal process. In particular, the exact magnetization configurations at the top end of the nano-ring are illustrated using magnetic force microscopy (MFM) that is facilitated with a photoresist etch-back technique. Most interestingly, MFM images of two sets of head-to-head (H2H)/tail-to-tail (T2T) domain walls are captured during the magnetization reversal process. It is believed that the domain walls formation and evolution processes at the top end of the nano-ring are mediated by the anti-symmetrical distribution of the vortex domain wall on the tubular sidewalls. Simulation results using Object Oriented Micromagnetic Framework confirm the MOKE hysteresis loop and MFM imaging.

Chao, C. T.; Huang, Y. C.; Kuo, C. Y.; Horng, Lance; Wu, J. C.

2013-05-01

337

Assessment of bronchial wall thickness and lumen diameter in human adults using multi-detector computed tomography: comparison with theoretical models  

PubMed Central

A thickened bronchial wall is the morphological substratum of most diseases of the airway. Theoretical and clinical models of bronchial morphometry have so far focused on bronchial lumen diameter, and bronchial length and angles, mainly assessed from bronchial casts. However, these models do not provide information on bronchial wall thickness. This paper reports in vivo values of cross-sectional wall area, lumen area, wall thickness and lumen diameter in ten healthy subjects as assessed by multi-detector computed tomography. A validated dedicated software package was used to measure these morphometric parameters up to the 14th bronchial generation, with respect to Weibel's model of bronchial morphometry, and up to the 12th according to Boyden's classification. Measured lumen diameters and homothety ratios were compared with theoretical values obtained from previously published studies, and no difference was found when considering dichotomic division of the bronchial tree. Mean wall area, lumen area, wall thickness and lumen diameter were then provided according to bronchial generation order, and mean homothety ratios were computed for wall area, lumen area and wall thickness as well as equations giving the mean value of each parameter for a given bronchial generation with respect to its value in generation 0 (trachea). Multi-detector computed tomography measurements of bronchial morphometric parameters may help to improve our knowledge of bronchial anatomy in vivo, our understanding of the pathophysiology of bronchial diseases and the evaluation of pharmacological effects on the bronchial wall.

Montaudon, M; Desbarats, P; Berger, P; de Dietrich, G; Marthan, R; Laurent, F

2007-01-01

338

The hypertrophy of the lateral abdominal wall and quadratus lumborum is sport-specific: an MRI segmental study in professional tennis and soccer players.  

PubMed

The aim was to determine the volume and degree of asymmetry of quadratus lumborum (QL), obliques, and transversus abdominis; the last two considered conjointly (OT), in tennis and soccer players. The volume of QL and OT was determined using magnetic resonance imaging in professional tennis and soccer players, and in non-active controls (n = 8, 14, and 6, respectively). In tennis players the hypertrophy of OT was limited to proximal segments (cephalic segments), while in soccer players it was similar along longitudinal axis. In tennis players the hypertrophy was asymmetric (18% greater volume in the non-dominant than in the dominant OT, p = 0.001), while in soccer players and controls both sides had similar volumes (p > 0.05). In controls, the non-dominant QL was 15% greater than that of the dominant (p = 0.049). Tennis and soccer players had similar volumes in both sides of QL. Tennis alters the dominant-to-non-dominant balance in the muscle volume of the lateral abdominal wall. In tennis the hypertrophy is limited to proximal segments and is greater in the non-dominant side. Soccer, however, is associated to a symmetric hypertrophy of the lateral abdominal wall. Tennis and soccer elicit an asymmetric hypertrophy of QL. PMID:23724609

Sanchis-Moysi, Joaquin; Idoate, Fernando; Izquierdo, Mikel; Calbet, Jose A; Dorado, Cecilia

2013-03-01

339

Successful percutaneous treatment for massive hemorrhage due to infectious pseudoaneurysm in the abdominal wall after percutaneous endoscopic gastrostomy: a case report  

PubMed Central

Background Percutaneous endoscopic gastrostomy (PEG) is often performed for alimentation and to prevent weight loss in patients with feeding problems due to central neurologic diseases such as cerebral infarction or intracranial hemorrhage. Although infection at the skin site after PEG placement is a typical late complication of PEG, a ruptured infectious pseudoaneurysm caused massive bleeding adjacent to the tract is rare. Prompt treatment is required to avoid the hemorrhage shock, however surgical ligation is difficult to obtain the arrest of bleeding in damaged skin due to the infection. Case presentation A 70-year-old male was bedridden due a cerebral infarction suffered 1 year previously. APEG was placed because of feeding problems, and a push-type, 20-Fr gastrostomy tube was inserted through the anterior abdominal wall. On day 16 after PEG placement, the patient had massive bleeding from the PEG site due to the rupture of infectious pseudoaneurysm and developed a decreased level of consciousness and hypotension. Treatment by percutaneous direct injection of a mixture of n-butyl-cyanoacrylate (NBCA)-lipiodol was performed and achieved good hemostasis is obtained. Conclusions A rare case of an infectious pseudoaneurysm that developed in the abdominal wall and caused massive bleeding at a PEG placement site was described. Percutaneous injection of a mixture of n-butyl-cyanoacrylate (NBCA)-lipiodol under ultrasound guidance is an effective treatment in this case.

2014-01-01

340

Biliary peritonitis caused by a leaking T-tube fistula disconnected at the point of contact with the anterior abdominal wall: a case report  

PubMed Central

Introduction Operations on the common bile duct may lead to potentially serious complications such as biliary peritonitis. T-tube insertion is performed to reduce the risk of this occurring postoperatively. Biliary leakage at the point of insertion into the common bile duct, or along the fistula, can sometimes occur after T-tube removal and this has been reported extensively in the literature. We report a case where the site at which the T-tube fistula leaked proved to be the point of contact between the fistula and the anterior abdominal wall, a previously unreported complication. Case presentation A 36-year-old sub-Saharan African woman presented with gallstone-induced pancreatitis and, once her symptoms settled, laparoscopic cholecystectomy was performed, common bile duct stones were removed and a T-tube was inserted. Three weeks later, T-tube removal led to biliary peritonitis due to the disconnection of the T-tube fistula which was recannulated laparoscopically using a Latex drain. Conclusion This case highlights a previously unreported mechanism for bile leak following T-tube removal caused by detachment of a fistula tract at its contact point with the anterior abdominal wall. Hepatobiliary surgeons should be aware of this mechanism of biliary leakage and the use of laparoscopy to recannulate the fistula.

Nikolic, Marko; Karthikesalingam, Alan; Nachimuthu, Senthil; Tang, Tjun Y; Harris, Adrian M

2008-01-01

341

A temperature correlation for the radiation resistance of a thick-walled circular duct exhausting a hot gas  

NASA Technical Reports Server (NTRS)

It is often useful to know the radiation impedance of an unflanged but thick-walled circular duct exhausting a hot gas into relatively cold surroundings. The reactive component is shown to be insensitive to temperature, but the resistive component is shown to be temperature dependent. A temperature correlation is developed permitting prediction of the radiation resistance from a knowledge of the temperature difference between the ambient air and the gas flowing from the duct, and a physical basis for this correlation is presented.

Mahan, J. R.; Cline, J. G.; Jones, J. D.

1984-01-01

342

A comparative assessment of the wall thickness margin taking into account the initial flaws in steam line elements  

NASA Astrophysics Data System (ADS)

A procedure for estimating the wall thickness margin for operation during a specified design service life under creep conditions if the metal of articles contains initial flaws is presented. The analysis is carried out taking as an example parts of steam lines made of two different grades of steel: a cast elbow with the size d = 426 × 30 mm made of 15Kh1M1FL low-alloy steel and a pipe bend with the size d = 219 × 32 mm made of EI-756 12% chromium steel. The calculated assessments are compared with the results obtained from long-term operation.

Gladshtein, V. I.

2011-02-01

343

Airway wall thickness in patients with near fatal asthma and control groups: assessment with high resolution computed tomographic scanning  

PubMed Central

BACKGROUND—Airway wall thickening has been observed in post mortem studies of patients with asthma. Assessment of airway wall thickening by high resolution computed tomographic (HRCT) scanning has been reported in experimental studies. We have used HRCT scanning to measure airway wall thickness at the segmental and subsegmental levels in 40 patients with asthma and 14 normal controls.?METHODS—The subjects were prospectively divided into four age and sex matched groups: 14 patients with a history of near fatal attack of asthma (NFA; group 1), 12 patients with moderate asthma (group 2), 13 patients with mild asthma (group 3), and 14 normal controls (group 4). All subjects were non-smokers. High resolution (1 mm collimation) CT scans of the chest were done at five different levels.?RESULTS—The mean (SD) forced expiratory volume in one second (FEV1) was 68 (20)% of predicted for group 1, 73 (12)% for group 2, 102(12)% for group 3, and 103 (12)% for group 4. The ratio of airway wall thickness to outer diameter (T/D) and the percentage wall area (WA%) defined as (wall area/total airway area) × 100 were used to compare airway wall thickness between the groups. The mean (SD) T/D and WA% were 0.27 (0.05) and 78.0 (9.2)% for group 1, 0.27 (0.05) and 78.8 (9.2)% for group 2, 0.25 (0.04) and 74.2(7.5)% for group 3, and 0.23 (0.04) and 70.9 (8.2)% for group 4. T/D and WA% were not significantly different between groups 1 and 2. However, both groups 1 and 2 had higher T/D and WA% than either group 3 or 4 (p < 0.001) and group 3 had a higher T/D and WA% than group 4 (p < 0.03).The differences (95% CI) between the groups in WA% were 7.1% (0 to 14.4) for groups 1 and 4, 3.8% (-3.4 to 10) for groups 1 and 3, and 3.3% (-4.4 to 10) for groups 3and 4. The differences between the groups in T/D and WA% were noted both for those with airways with a luminal diameter of >2 mm and those with a luminal diameter of ?2 mm.?CONCLUSIONS—All the patient groups had greater airway wall thickening than the normal subjects as assessed by HRCT scanning, but patients with more severe asthma had greater airway wall thickening than those with mild asthma. The methodology described in this study may be useful in assessing airway calibre in early intervention studies with anti-inflammatory therapy.??

Awadh, N.; Muller, N.; Park, C.; Abboud, R.; FitzGerald, J

1998-01-01

344

Inelastic local buckling of flat, thin-walled structures containing thickness-tapered plates  

Microsoft Academic Search

This paper is concerned with the inelastic local buckling of flat plate structures that contain plates with variable thicknesses. Use is made of the semi-analytical complex finite strip method, which is augmented with transverse bubble functions. Stiffness and stability matrices are derived for inclusion in the finite strip method, which is based on the deformation theory of plasticity. The numerical

M. Azhari; M. M. Saadatpour; M. A. Bradford

2004-01-01

345

Abdominal Adhesions  

MedlinePLUS

... cavity to stick together. What is the abdominal cavity? The abdominal cavity is the internal area of the body between ... adhesions cause tissues and organs in the abdominal cavity to stick together. • Abdominal surgery is the most ...

346

Abdominal Adhesions  

MedlinePLUS

... tissues and organs. [ Top ] What is the abdominal cavity? The abdominal cavity is the internal area of the body between ... adhesions cause tissues and organs in the abdominal cavity to stick together. Abdominal surgery is the most ...

347

Stress concentration analysis of thick-walled laminate composites with a loaded circular cut-out by using a first-order shear deformation theory  

Microsoft Academic Search

Stress concentrations in the vicinity of cut-outs can often be regarded as design drivers for the whole structure. Especially in thick-walled laminate composites not only the extension-bending coupling effects but as well the influence of the shear deformation has to be taken into account. For analyzing stress concentration effects in the vicinity of circular cut-outs in thick-walled anisotropic composites, sophisticated

W. Hufenbach; R. Gottwald; B. Grüber; M. Lepper; B. Zhou

2008-01-01

348

Fracture resistance of welded thick-walled high-pressure vessels in power plants. Report No. 2. Approach to evaluating static strength  

Microsoft Academic Search

The authors examine data on the effect of defects on the fracture resistance of high-pressure vessels and their models obtained within the framework of the HSST program. Results of internal-pressure tests of two types of vessels with a wall thickness of 152 mm made from forgings of steels SA508 and SA533, as well as small vessels with a wall thickness

I. V. Gorynin; V. M. Filatov; V. A. Ignatov; B. T. Timofeev; Yu. I. Zvezdin

1986-01-01

349

Axisymmetric Tandem Mirror Magnetic Fusion Energy Power Plant with Thick Liquid-Walls  

SciTech Connect

A fusion power plant is described that utilizes a new version of the tandem mirror device including spinning liquid walls. The magnetic configuration is evaluated with an axisymmetric equilibrium code predicting an average beta of 60%. The geometry allows a flowing molten salt, (flibe-Li{sub 2}BeF{sub 4}), which protects the walls and structures from damage arising from neutrons and plasma particles. The free surface between the liquid and the burning plasma is heated by bremsstrahlung radiation, line radiation, and by neutrons. The temperature of the free surface of the liquid is calculated, and then the evaporation rate is estimated from vapor-pressure data. The allowed impurity concentration in the burning plasma is taken as 1% fluorine, which gives a 17% reduction in the fusion power owing to D/T fuel dilution, with F line-radiation causing minor power degradation. The end leakage power density of 0.6 MW/m{sup 2} is readily handled by liquid jets. The tritium breeding is adequate with natural lithium. A number of problem areas are identified that need further study to make the design more self-consistent and workable; however, the simple geometry and the use of liquid walls promise the cost of power competitive with that from fission and coal.

Moir, R W; Rognlien, T D

2006-04-26

350

Stresses in thick-walled FGM cylinders with exponentially-varying properties  

Microsoft Academic Search

Power series solutions for stresses and displacements in functionally-graded cylindrical vessels subjected to internal pressure alone are obtained using the infinitesimal theory of elasticity. The material is assumed to be isotropic with constant Poisson’s ratio and exponentially-varying elastic modulus through the thickness. Stress distributions depending on an inhomogeneity constant are calculated and presented in the form of graphs. The inhomogeneity

Naki Tutuncu

2007-01-01

351

Instrumented thick-walled tube method for measuring thermal pressure in fluids and isotropic stresses in thermosetting resins  

NASA Astrophysics Data System (ADS)

We have developed a method for measuring the thermal pressure coefficient and cure-induced and thermally induced stresses based on an instrumented thick-walled tube vessel. The device has been demonstrated at pressures up to 330 MPa and temperatures to 300 °C. The method uses a sealed stainless steel thick-walled tube to impose three-dimensional isotropic constraints. The tube is instrumented with strain gauges in hoop and in axial directions and can be used in open or closed configurations. By making measurements of the isotropic stresses as a function of temperature, the method allows determination of the thermal pressure coefficient in both the glassy and rubbery (or liquid) states. The method also can be used to measure isotropic stress development in thermosetting resins during cure and subsequent thermal cycling. Experimental results are presented for sucrose benzoate, di-2-ethylhexylsebacate, and an epoxy resin. The current report shows that the method provides reliable estimates for the thermal pressure coefficient. The thermal pressure coefficient is determined with resolution on the order of 10 kPa/K. Among advantages of the method is that the tubes are reusable, even when measurements are made for cure response of thermosetting resins.

Merzlyakov, Mikhail; Simon, Sindee L.; McKenna, Gregory B.

2005-06-01

352

FRAM isotopic analysis of uranium in thick-walled containers using high energy gamma rays and planar HPGe detectors.  

SciTech Connect

We describe the use of the Los Alamos FRAM isotopic analysis software to make the first reported measurements on thick-walled UF{sub 6} cylinders using small planar HPGe detectors of the type in common use at the IAEA. Heretofore, planar detector isotopic analysis measurements on uranium have used the 100-keV region and can be defeated by 10 mm of steel absorber. The analysis of planar detector measurements through 13-16 mm of steel shows that FRAM can successfully carry out these measurements and analysis in the 120-1024 keV energy range, a range previously thought to be the sole province of more efficient coaxial detectors. This paper describes the measurement conditions and results and also compares the results to other FRAM measurements with coaxial HPGe detectors. The technique of gamma-ray isotopic analysis of arbitrary samples is desirable for measuring the isotopic composition of uranium in UF{sub 6} cylinders because it does not require calibration with standards or knowledge of the cylinder wall thickness. The International Atomic Energy Agency (IAEA) uses the MGAU (Multi Group Analysis Uranium) uranium isotopic analysis software with planar high purity germanium (HPGe) detectors to measure the isotopic composition of uranium. Measurements on UF{sub 6} cylinders with 13-16-mm thick steel walls are usually unsuccessful because of the strong absorption of the 89-100 keV gamma rays and x-rays that MGAU requires for the measurement. This paper describes the use of the Los Alamos FRAM isotopic analysis software to make these measurements on UF{sub 6} cylinders. Uranium measurements with FRAM typically cover the energy range from 120-1001 keV and can easily be made through the walls of UF{sub 6} cylinders. While these measurements are usually performed with efficient coaxial HPGe detectors, this paper reports the first successful measurements using small planar HPGe detectors of the type in common use at the IAEA.

Sampson, Thomas E.; Hypes, P. A. (Philip A.); Vo, Duc T.

2002-01-01

353

Analytical solution for the pseudoelastic response of a shape memory alloy thick-walled cylinder under internal pressure  

NASA Astrophysics Data System (ADS)

Analytical solutions are derived for the isothermal pseudoelastic response of a shape memory alloy (SMA) thick-walled cylinder subjected to internal pressure. The Tresca transformation criterion and linear hardening are used. Equations are given for the radial and circumferential stresses, transformation strains and radial displacement at various steps of loading and unloading. A structural pressure-temperature phase diagram is provided for the cylinder, analogous to the stress-temperature phase diagram of SMA materials. Pressurization of an initially 100% austenitic cylinder causes the martensite to initially form at the inner radius. For a relatively thin-walled cylinder the transformation front reaches the outer radius before the transformation has completed at the inner radius, whereas for a thick-walled cylinder the transformation completes at the inner radius while there is still an outer ring of 100% austenite. For a given OD/ID ratio, a critical temperature is derived that stipulates which of these two cases occurs. An analytical result is provided for the pressure that will cause the transformation to complete at the inner radius. During unloading, the reverse transformation can start at either the inner or the outer surface of the cylinder and can propagate outward and then reverse its direction and propagate back to the inner surface. The effect of martensitic transformation on the structural yield strength due to plasticity is also investigated and it is shown that the pressure required to initiate yielding can be substantially decreased or increased depending on the temperature and the state of transformation achieved, even though the yield stress of the material is independent of temperature. Finally, the effectiveness of the Tresca transformation criterion to derive closed-form solutions for this problem is demonstrated by comparing with finite element solutions using the von Mises theory.

Tabesh, M.; Liu, B.; Boyd, J. G.; Lagoudas, D. C.

2013-09-01

354

Thick growing multilayer nanobrick wall thin films: super gas barrier with very few layers.  

PubMed

Recent work with multilayer nanocoatings composed of polyelectrolytes and clay has demonstrated the ability to prepare super gas barrier layers from water that rival inorganic CVD-based films (e.g., SiOx). In an effort to reduce the number of layers required to achieve a very low oxygen transmission rate (OTR (<0.01 cc/m(2)·day·atm)) in these nanocoatings, buffered cationic chitosan (CH) and vermiculite clay (VMT) were deposited using layer-by-layer (LbL) assembly. Buffering the chitosan solution and its rinse with 50 mM Trizma base increased the thickness of these films by an order of magnitude. The OTR of a 1.6-?m-thick, six-bilayer film was 0.009 cc/m(2)·day·atm, making this the best gas barrier reported for such a small number of layers. This simple modification to the LbL process could likely be applied more universally to produce films with the desired properties much more quickly. PMID:24914613

Guin, Tyler; Krecker, Michelle; Hagen, David Austin; Grunlan, Jaime C

2014-06-24

355

The use of thick-walled hollow cylinder creep tests for evaluating flow criteria for rock salt  

SciTech Connect

Finite element simulations of two laboratory creep tests on thick-walled hollow cylinders of rock salt are evaluated to determine if such bench-scale experiments can be used to establish applicability of either von Mises or Tresca stress measures and associated flow conditions. In the tests, the cylinders were loaded axially and pressurized both internally and externally to produce stress fields similar to those found around underground excavations in rock salt. Several different loading stages were used in each test. The simulations show that for each of two creep models studied, quite different deformations of the cylinders are predicted with the Mises and Tresca flow criteria, especially if friction between the cylinders and axial loading platens is ignored. When friction is included in the simulations, the differences in deformation are changed but are sill clearly distinguishable. 10 refs., 10 figs.

Morgan, H.S.; Wawersik, W.R.

1990-01-01

356

A state of the art review on intima-media thickness (IMT) measurement and wall segmentation techniques for carotid ultrasound.  

PubMed

Last 10 years have witnessed the growth of many computer applications for the segmentation of the vessel wall in ultrasound imaging. Epidemiological studies showed that the thickness of the major arteries is an early and effective marker of onset of cardiovascular diseases. Ultrasound imaging, being real-time, economic, reliable, safe, and now seems to become a standard in vascular assessment methodology. This review is an attempt to discuss the most performing methodologies that have been developed so far to perform computer-based segmentation and intima-media thickness (IMT) measurement of the carotid arteries in ultrasound images. First we will present the rationale and the clinical relevance of computer-based measurements in clinical practice, followed by the challenges that one has to face when approaching the segmentation of ultrasound vascular images. The core of the paper is the presentation, discussion, benchmarking and evaluation of different segmentation techniques, including: edge-detection, active contours, dynamic programming, local statistics, Hough transform, statistical modeling, and integration of these approaches. Also, we will discuss and compare the different performance metrics that have been proposed and used to perform the validation. Best performing user-dependent techniques show an average IMT measurement error of about 1?m when compared to human tracings [57], whereas completely automated techniques show errors of about 10?m. The review ends with a discussion about the current standards in carotid wall segmentation and in an overview of the future perspectives, which may include the adoption of advanced and intelligent strategies to let the computer technique measure the IMT in the image portion where measurement is more reliable. PMID:20478640

Molinari, Filippo; Zeng, Guang; Suri, Jasjit S

2010-12-01

357

Fetal aortic wall thickness: a marker of hypertension in IUGR children?  

PubMed

Fetuses with intrauterine growth restriction (IUGR) have significant aortic intima-media thickening (aIMT), which suggests that preclinical atherosclerosis might predispose the infants to hypertension. However, the natural course of aIMT in babies with IUGR remains an open question.The study enrolled 77 pregnant women between January 2007 and August 2009. The fetuses were classified as AGA (appropriate for gestational age) or IUGR, if the estimated fetal weight was between the 10th and 90th percentile or below the 10th percentile (with umbilical artery pulsatility index (PI) >2s.d.), respectively. Anthropometric parameters and aIMT were detected in each IUGR and AGA fetus at a mean gestational age of 32 weeks. The follow-up was performed in 25 IUGR and 25 AGA infants at a mean postnatal age of 18 months; the previous measurements were repeated, and blood pressure measurements were taken. The maximum aIMT was significantly higher in the IUGR fetuses and infants compared with the AGA infants, both in utero (2.05±0.43 vs. 1.05±0.19?mm, P<0.001) and at the follow-up (2.3±0.8 vs. 1.06±0.18?mm, P<0.0001), the resulting values significantly correlated (P=0.018) with one another. The systolic blood pressure was significantly increased in the IUGR subjects (123±16 vs. 104±8.5?mm?Hg, P<0.0004), and it correlated with the prenatal and postnatal aIMT values (P<0.0156 and P<0.0054, respectively). The aortic wall thickening progression in IUGR fetuses and infants differed from AGA, which may predispose the infants to hypertension early in life and cardiovascular risk later in life. PMID:23364342

Zanardo, Vincenzo; Visentin, Silvia; Trevisanuto, Daniele; Bertin, Martina; Cavallin, Francesco; Cosmi, Erich

2013-05-01

358

Accuracy Evaluation in the Measurement of a Small Change in the Thickness of Arterial Walls and the Measurement of Elasticity of the Human Carotid Artery  

NASA Astrophysics Data System (ADS)

For the diagnosis of the early stages of atherosclerosis, it isimportant to evaluate the local acoustic characteristics of thearterial wall. For this purpose, it is necessary to increase thespatial resolution in the axial direction to several millimeters,which corresponds to the size of the macular lesion on the surface ofthe wall. We have proposed a method for measuring small velocitysignals on the intima and adventitia of the arterial wall from theskin surface using pulsive ultrasonic waves. The small change inthickness of the arterial wall is obtained by integrating thedifference between the two velocity signals on the intima andadventitia. The elastic property of the arterial wall is noninvasivelyevaluated from the change in thickness and the arterial innerpressure. In this paper, we evaluate the accuracy of the proposedmethod for measuring the small displacement. Moreover, we applied thismethod to evaluate the elastic property of the arterial wall of 50patients and 8 healthy subjects.

Hasegawa, Hideyuki; Kanai, Hiroshi; Hoshimiya, Nozomu; Chubachi, Noriyoshi; Koiwa, Yoshiro

1998-05-01

359

High resolution computed tomographic assessment of airway wall thickness in chronic asthma: reproducibility and relationship with lung function and severity  

PubMed Central

Background: In some patients chronic asthma results in irreversible airflow obstruction. High resolution computed tomography (HRCT) has been advocated for assessing the structural changes in the asthmatic lung and permits investigation of the relationships between airway wall thickening and clinical parameters in this condition. Methods: High resolution CT scanning was performed in 49 optimally controlled asthmatic patients and measurements of total airway and lumen diameter were made by two independent radiologists using electronic callipers. Wall area as % total airway cross sectional area (WA%) and wall thickness to airway diameter ratio (T/D) were calculated for all airways clearly visualised with a transverse diameter of more than 1.5 mm, with a mean value derived for each patient. Intra- and inter-observer variability was assessed for scope of agreement in a subgroup of patients. Measurements were related to optimum forced expiratory volume in 1 second (FEV1), forced mid expiratory flow, carbon monoxide gas transfer, two scores of asthma severity, airway inflammation as assessed with induced sputum, and exhaled nitric oxide. Results: Neither observer produced a statistically significant difference between measurements performed on two occasions but there was a significant difference between observers (limits of agreement –2.6 to 6.8 for WA%, p<0.0001). However, mean WA% measured on two occasions differed by no more than 5.4% (limits of agreement –4.0 to 5.4; mean (SD) 0.7 (2.4)). Statistically significant positive associations were observed between both WA% and T/D ratio and asthma severity (rS=0.29 and 0.30, respectively, for ATS score), and an inverse association with gas transfer coefficient was observed (rS=–0.43 for WA% and rS=–0.41 for T/D). No association was identified with FEV1 or airway inflammation. Conclusions: The airway wall is thickened in more severe asthma and is associated with gas transfer coefficient. This thickening does not relate directly to irreversible airflow obstruction as measured with FEV1.

Little, S; Sproule, M; Cowan, M; Macleod, K; Robertson, M; Love, J; Chalmers, G; McSharry, C; Thomson, N

2002-01-01

360

Effect of an oblique and constant magnetic field in the sheath thickness, the floating potential and the saturation current collected by a planar wall  

NASA Astrophysics Data System (ADS)

This work studies the sheath close to a negatively polarized wall in an oblique and constant magnetic field. We also consider ionization and collisions and study the effect of the different pre-sheath mechanisms on such properties as the current to voltage characteristics, the saturation current collected by the wall, the floating potential and the sheath thickness. This last property being the most sensitive to the change in the dominant pre-sheath mechanism which allows the sheath to form.

Morales Crespo, R.; Franklin, R. N.

2014-06-01

361

The impact of a massive transfusion protocol (1:1:1) on major hepatic injuries: Does it increase abdominal wall closure rates?  

PubMed Central

Background Massive transfusion protocols (MTPs) using high plasma and platelet ratios for exsanguinating trauma patients are increasingly popular. Major liver injuries often require massive resuscitations and immediate hemorrhage control. Current published literature describes outcomes among patients with mixed patterns of injury. We sought to identify the effects of an MTP on patients with major liver trauma. Methods Patients with grade 3, 4 or 5 liver injuries who required a massive blood component transfusion were analyzed. We compared patients with high plasma:red blood cell:platelet ratio (1:1:1) transfusions (2007–2009) with patients injured before the creation of an institutional MTP (2005–2007). Results Among 60 patients with major hepatic injuries, 35 (58%) underwent resuscitation after the implementation of an MTP. Patient and injury characteristics were similar between cohorts. Implementation of the MTP significantly improved plasma: red blood cell:platelet ratios and decreased crystalloid fluid resuscitation (p = 0.026). Rapid improvement in early acidosis and coagulopathy was superior with an MTP (p = 0.009). More patients in the MTP group also underwent primary abdominal fascial closure during their hospital stay (p = 0.021). This was most evident with grade 4 injuries (89% vs. 14%). The mean time to fascial closure was 4.2 days. The overall survival rate for all major liver injuries was not affected by an MTP (p = 0.61). Conclusion The implementation of a formal MTP using high plasma and platelet ratios resulted in a substantial increase in abdominal wall approximation. This occurred concurrently to a decrease in the delivered volume of crystalloid fluid.

Ball, Chad G.; Dente, Christopher J.; Shaz, Beth; Wyrzykowski, Amy D.; Nicholas, Jeffrey M.; Kirkpatrick, Andrew W.; Feliciano, David V.

2013-01-01

362

Linear abdominal trauma.  

PubMed

Three cases of blunt abdominal trauma are presented to exemplify the mechanism of trauma and the problems of diagnosis associated with any linear blow to the abdomen. The mechanisms of visceral injury are reviewed, and special attention is directed to the abdominal wall injury that can be present in these patients. This injury has special implications in directing the operative approach and repair. An unusual aortic occlusion is described which is peculiar to this type of injury. PMID:130499

Danto, L A; Wolfman, E F

1976-03-01

363

Analysis of the Effect of Osteon Diameter on the Potential Relationship of Osteocyte Lacuna Density and Osteon Wall Thickness  

PubMed Central

An important hypothesis is that the degree of infilling of secondary osteons (Haversian systems) is controlled by the inhibitory effect of osteocytes on osteoblasts, which might be mediated by sclerostin (a glycoprotein produced by osteocytes). Consequently, this inhibition could be proportional to cell number: relatively greater repression is exerted by progressively greater osteocyte density (increased osteocytes correlate with thinner osteon walls). This hypothesis has been examined, but only weakly supported, in sheep ulnae. We looked for this inverse relationship between osteon wall thickness (On.W.Th) and osteocyte lacuna density (Ot.Lc.N/B.Ar) in small and large osteons in human ribs, calcanei of sheep, deer, elk, and horses, and radii and third metacarpals of horses. Analyses involved: (1) all osteons, (2) smaller osteons, either ?150?m diameter or ? the mean diameter, and (3) larger osteons (>mean diameter). Significant, but weak, correlations between Ot.Lc.N/B.Ar and On.W.Th/On.Dm (On.Dm = osteon diameter) were found when considering all osteons in limb bones (r values ?0.16 to ?0.40, p<0.01; resembling previous results in sheep ulnae: r= ?0.39, p<0.0001). In larger osteons, these relationships were either not significant (five/seven bone types) or very weak (two/seven bone types). In ribs, a negative relationship was only found in smaller osteons (r= ?0.228, p<0.01); this inverse relationship in smaller osteons did not occur in elk calcanei. These results do not provide clear or consistent support for the hypothesized inverse relationship. However, correlation analyses may fail to detect osteocyte-based repression of infilling if the signal is spatially non-uniform (e.g., increased near the central canal).

Skedros, John G.; Clark, Gunnar C.; Sorenson, Scott M.; Taylor, Kevin W.; Qiu, Shijing

2011-01-01

364

Measurement of defect thickness of the wall thinning defect pipes by lock-in infrared thermography technique  

NASA Astrophysics Data System (ADS)

Mostly piping which is using for the nuclear power plants are made up of carbon steel pipes. The wall thinning defects occurs by the effect of the flow accelerated corrosion of fluid that flows in carbon steel pipes. The defects could be found on the welding part and anywhere in the pipes. The infrared thermography technique which is one of the non-destructive testing method has used for detecting the defects of various kinds of materials over the years. There is a limitation for measuring the defect of metals that have a big coefficient of thermal diffusion. However, a technique using lock-in method gets over the difficulty. Consequently, the lock-in infrared thermography technique has been applied to the various industry fields. In this paper, the defect thickness of the straight pipe which has an artificial defect the inside of the pipes was measured by using the lock-in infrared thermography technique and the result could be utilized in detecting defects of carbon steel pipes.

Kim, Kyeongsuk; Kim, Kyungsu; Jung, Hyunchul; Chang, Hosub

2009-12-01

365

Failure Analysis of Weld Cracking in a Thick-Walled 2.25Cr-1Mo Steel Pressure Vessel  

NASA Astrophysics Data System (ADS)

A crack in thick-walled 2.25Cr-1Mo steel pressure vessel girth weld was found during manufacturing. To investigate the cause of failure, optical microscopy, scanning electron microscopy, energy dispersive spectrometer, transmission electron microscopy, and microhardness tester were used in this study. According to test results, the fracture is classified as reheat cracking with multiple origins. The cracking occurred during surfacing or final post-weld heat treatment process. Coarse-grains in the weld and bulk-carbides precipitated along grain boundaries induced by multiple heating are main causes of the fracture from material aspect, while high level of the hoop stress component and excess localized deformation in stress relief procedure are mechanical aspect causes of the cracking. The fracture surfaces present major intergranular feature with a small fraction of transgranular morphologies. Large numbers of M3C and M23C6 carbides particles were found on the fracture surface, these carbides mainly precipitated on prior austenite-grain boundaries, columnar-grain boundaries, and sub-grain boundaries. Additionally, several proposals were also offered to reduce weld cracking of 2.25Cr-1Mo steel pressure vessels.

Lei, Xiaowei; Niu, Jing; Zhang, Jianxun; Fu, Anqing; Feng, Yaorong

2014-04-01

366

Identification of a pleiotropic locus on chromosome 7q for a composite left ventricular wall thickness factor and body mass index: the HyperGEN Study  

Microsoft Academic Search

BACKGROUND: Left ventricular (LV) mass and wall thickness are closely associated with measures of body size and blood pressure and also correlated with systolic and diastolic function, suggesting a contribution of common physiologic mechanisms, including pleiotropic genes, to their covariation. METHODS: Doppler echocardiography was performed in 434 African-American (1344 individuals) and 284 white families (1119 individuals). We conducted a genome-wide

Weihong Tang; Richard B Devereux; Na Li; Albert Oberman; Dalane W Kitzman; Dabeeru C Rao; Paul N Hopkins; Steven A Claas; Donna K Arnett

2009-01-01

367

Fast inspection of radius, wall thickness, eccentricity and ovality at the end of high precision tubes: TRUDE 60-28 in the production  

Microsoft Academic Search

In this paper we would like to present a new idea for measuring high precision tubes with an accuracy of +\\/- 10 micrometers . The most interesting values of the tubes are wall thickness, diameter, eccentricity and so on. The cycle of measuring is not more than 5 seconds inclusive the complete tube handling. The preferred sensor concept is the

Wolfram Kleuver; Juergen Weber; Detlef Justen; Klaus Hartmann

1997-01-01

368

Human coronary plaque wall thickness correlated positively with flow shear stress and negatively with plaque wall stress: an IVUS-based fluid-structure interaction multi-patient study  

PubMed Central

Background Atherosclerotic plaque progression and rupture are believed to be associated with mechanical stress conditions. In this paper, patient-specific in vivo intravascular ultrasound (IVUS) coronary plaque image data were used to construct computational models with fluid-structure interaction (FSI) and cyclic bending to investigate correlations between plaque wall thickness and both flow shear stress and plaque wall stress conditions. Methods IVUS data were acquired from 10 patients after voluntary informed consent. The X-ray angiogram was obtained prior to the pullback of the IVUS catheter to determine the location of the coronary artery stenosis, vessel curvature and cardiac motion. Cyclic bending was specified in the model representing the effect by heart contraction. 3D anisotropic FSI models were constructed and solved to obtain flow shear stress (FSS) and plaque wall stress (PWS) values. FSS and PWS values were obtained for statistical analysis. Correlations with p?wall thickness and flow shear stress. The mean Pearson correlation r-value was 0.278?±?0.181. Similarly, 9 out of the 10 patients showed negative correlation between wall thickness and plaque wall stress. The mean Pearson correlation r-value was -0.530?±?0.210. Conclusion Our results showed that plaque vessel wall thickness correlated positively with FSS and negatively with PWS. The patient-specific IVUS-based modeling approach has the potential to be used to investigate and identify possible mechanisms governing plaque progression and rupture and assist in diagnosis and intervention procedures. This represents a new direction of research. Further investigations using more patient follow-up data are warranted.

2014-01-01

369

A tale of two neglected systems--structure and function of the thin- and thick-walled sieve tubes in monocotyledonous leaves  

PubMed Central

There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5–7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer.

Botha, C. E. J.

2013-01-01

370

Method and apparatus to produce and maintain a thick, flowing, liquid lithium first wall for toroidal magnetic confinement DT fusion reactors  

DOEpatents

A system for forming a thick flowing liquid metal, in this case lithium, layer on the inside wall of a toroid containing the plasma of a deuterium-tritium fusion reactor. The presence of the liquid metal layer or first wall serves to prevent neutron damage to the walls of the toroid. A poloidal current in the liquid metal layer is oriented so that it flows in the same direction as the current in a series of external magnets used to confine the plasma. This current alignment results in the liquid metal being forced against the wall of the toroid. After the liquid metal exits the toroid it is pumped to a heat extraction and power conversion device prior to being reentering the toroid.

Woolley, Robert D. (Hillsborough, NJ)

2002-01-01

371

Coronary Artery Calcium, Carotid Artery Wall Thickness and Cardiovascular Disease Outcomes in Adults 70 to 99 Years Old  

PubMed Central

Few population studies have evaluated the associations of both coronary artery calcium (CAC) and carotid ultrasound with cardiovascular events, especially in adults > 70 years of age. At the Pittsburgh Field Center of the Cardiovascular Health Study, 559 men and women, mean age 80.2 (SD 4.1) years had CAC score assessed by electron beam computerized tomography scan and common and internal carotid intimal-medial wall thickness (CCA-IMT and ICA-IMT) by carotid ultrasound between 1998?2000 and were followed for total and incident cardiovascular disease events through June 2003. Crude rates and hazard ratios for total and incident events were examined with and without adjustment for cardiovascular risk factors. After 5 years, there were 127 cardiovascular disease events, 48 myocardial infarctions or cardiovascular disease deaths and 28 strokes or stroke deaths. Total and incident cardiovascular disease event rates were higher in each quartile of CAC and CCA-IMT, but not ICA-IMT. For total cardiovascular disease, the adjusted hazard ratio for the 4th vs. 1st quartile of CAC was 2.1 (95% CI = 1.2?3.9) and for CCA-IMT was 2.3 (95% CI = 1.3?4.1). The CCA-IMT was more strongly related to stroke risk than was CAC, though CAC was also an important predictor of stroke. No significant sex differences were found, though relative risks appeared to be stronger in women, especially for stroke. In conclusion, in these adults > 70 years of age, CAC and CCA-IMT had similar hazard ratios for total cardiovascular disease and coronary heart disease. The CCA-IMT was more strongly related to stroke than was CAC, but CAC was also a predictor of stroke.

Newman, Anne B.; Naydeck, Barbara L.; Ives, Diane G.; Boudreau, Robert M.; Sutton-Tyrrell, Kim; O'Leary, Daniel H.; Kuller, Lewis H.

2008-01-01

372

Low plasma lycopene concentration is associated with increased intima-media thickness of the carotid artery wall.  

PubMed

Although a number of epidemiological studies have evaluated the association between ss-carotene and the risk of cardiovascular diseases, there has been little research on the role of lycopene, an acyclic form of ss-carotene, with regard to the risk of cardiovascular disease. We investigated the relationship between plasma concentrations of lycopene and intima-media thickness of the common carotid artery wall (CCA-IMT) in 520 middle-aged men and women (aged 45 to 69 years) in eastern Finland. They were examined from 1994 to 1995 at the baseline of the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) study, a randomized trial concerning the effect of vitamin E and C supplementation on atherosclerotic progression. The subjects were classified into 2 categories according to the median concentration of plasma lycopene (0.12 micromol/L in men and 0.15 micromol/L in women). Mean CCA-IMT of the right and left common carotid arteries was 1.18 mm in men and 0.95 mm in women with plasma lycopene levels lower than the median and 0.97 mm in men (P:<0.001 for difference) and 0.89 mm in women (P:=0.027 for difference) with higher levels of plasma lycopene. In ANCOVA adjusting for cardiovascular risk factors and intake of nutrients, in men, low levels of plasma lycopene were associated with a 17.8% increment in CCA-IMT (P:=0.003 for difference). In women, the difference did not remain significant after the adjustments. We conclude that low plasma lycopene concentrations are associated with early atherosclerosis, manifested as increased CCA-IMT, in middle-aged men living in eastern Finland. PMID:11116071

Rissanen, T; Voutilainen, S; Nyyssönen, K; Salonen, R; Salonen, J T

2000-12-01

373

Fracture resistance of welded thick-walled high-pressure vessels in power plants. Report No. 2. Approach to evaluating static strength  

SciTech Connect

The authors examine data on the effect of defects on the fracture resistance of high-pressure vessels and their models obtained within the framework of the HSST program. Results of internal-pressure tests of two types of vessels with a wall thickness of 152 mm made from forgings of steels SA508 and SA533, as well as small vessels with a wall thickness of 11.5 and 23mm made of steel SA533 are shown. The authors state that testing thick-walled welded high-pressure vessels and thin-walled vessels with surface defects of different sizes has demonstrated that there are substantial static-strength reserves in structures designed by existing domestic and foreign standards on the strength of power-plant equipment. A correction was proposed for the presently used method of calculating the resistance of highpressure vessels to brittle fracture that allows for the dimensions of the defects in relation to the type of vessel, the manufacturing technology, and the method of inspection.

Gorynin, I.V.; Filatov, V.M.; Ignatov, V.A.; Timofeev, B.T.; Zvezdin, Yu. I.

1986-07-01

374

JAMA Patient Page: Abdominal Paracentesis  

MedlinePLUS

... blood pressure • Localized infection at the puncture site • Abdominal wall blood clots or bruises • Bleeding • Injury to organs in the abdomen Downloaded From: http://jama.jamanetwork.com/ by a ...

375

A prospective, controlled evaluation of the abdominal reapproximation anchor abdominal wall closure system in combination with VAC therapy compared with VAC alone in the management of an open abdomen.  

PubMed

Dramatic increases in damage control and decompressive laparotomies and a significant increase in patients with open abdominal cavities have resulted in numerous techniques to facilitate fascial closure. We hypothesized addition of the abdominal reapproximation anchor system (ABRA) to the KCI Abdominal Wound Vac™ (VAC) or KCI ABThera™ would increase successful primary closure rates and reduce operative costs. Fourteen patients with open abdomens were prospectively randomized into a control group using VAC alone (control) or a study group using VAC plus ABRA (VAC-ABRA). All patients underwent regular VAC changes; patients receiving VAC-ABRA also underwent concomitant daily elastomer adjustment of the ABRA system. Primary end points included abdominal closure, number of operating room (OR) visits, and OR time use. Eight patients were included in the VAC-ABRA group and six patients in the control group. Primary closure rates between groups were not statistically different; however, the number of trips to the OR and OR time use were different. Despite higher Acute Physiology and Chronic Health Evaluation II scores, larger starting wound size, and higher rates of abdominal compartment syndrome, closure rates in the VAC-ABRA group were similar to VAC alone. Importantly, however, fewer OR trips and less OR time were required for the VAC-ABRA group. PMID:24887794

Long, Kristin L; Hamilton, David A; Davenport, Daniel L; Bernard, Andrew C; Kearney, Paul A; Chang, Phillip K

2014-06-01

376

Temporal changes in regional end-diastolic wall thickness early after reperfusion in acute anterior myocardial infarction: Relation to myocardial viability and vascular damage  

Microsoft Academic Search

We investigated early temporal changes in end-diastolic wall thickness (EDWT) of the infarcted myocardium in 46 patients with reperfused anterior acute myocardial infarction in relation to myocardial viability. Two-dimensional echocardiography was performed on days 1 and 2 of acute myocardial infarction, and the EDWT of the anterior segment was measured in the short-axis view. Patients were divided into three groups

Hidemasa Oh; Hiroshi Ito; Katsuomi Iwakura; Tohru Masuyama; Shin Takiuchi; Atsushi Maruyama; Yorihiko Higashino; Kenshi Fujii; Junichi Azuma; Takazo Minamino

1996-01-01

377

A Possible Role for the Thick-walled Epidermal Cells in the Mycorrhizal Hair Roots of Lysinema ciliatum R. Br. and other Epacridaceae  

Microsoft Academic Search

Hair roots ofLysinema ciliatumR. Br. and some other Epacridaceae have thick-walled cells in the epidermis. These are preferentially colonized with mycorrhizal fungi. Individual epidermal cells containing hyphal coils separate at the middle lamella and are released into the soil. Other colonized cells remain attached to the roots, usually in groups, surrounded by bare exodermis, where epidermal cells have either collapsed

A. E. ASHFORD; W. G. ALLAWAY; M. L. REED

1996-01-01

378

Femoral artery wall thickness and stiffness in evaluation of peripheral vascular disease in type 2 diabetes mellitus  

Microsoft Academic Search

Stiffening and thickening of arterial wall are two important components of atherosclerosis. The purpose of this study was to evaluate the effects of femoral artery wall stiffness on clinical manifestation of peripheral vascular disease (PVD) in type 2 diabetes mellitus. The subjects were 315 patients with type 2 diabetes. Presence of intermittent claudication and\\/or leg pain at rest and reduced

Hiromichi Taniwaki; Tetsuo Shoji; Masanori Emoto; Takahiko Kawagishi; Eiji Ishimura; Masaaki Inaba; Yasuhisa Okuno; Yoshiki Nishizawa

2001-01-01

379

Relationship between airway wall thickness assessed by high-resolution computed tomography and lung function in patients with asthma and chronic obstructive pulmonary disease.  

PubMed

Airway remodeling in asthma and chronic obstructive pulmonary disease (COPD) results in thickening of bronchial walls and may affect lung function. In the present study we set out to evaluate the relationship between small airway wall thickness and the lung function parameters in patients with asthma and COPD. The study was performed in 10 patients with asthma (4M/6F, the mean age 37+/-13 yr) and 12 patients with COPD (7M/5F, the mean age 57+/-9 yr) with stable, mild to moderate disease. The study group characteristics were based on clinical assessment and lung function testing (spirometry, body plethysmography, methacholine challenge test). All patients underwent chest high resolution computerized tomography with small bronchi (external diameter 1-5 mm) cross section measurements at five selected lung levels. The following parameters were measured in end-inspiratory scans: external (D) and internal (L) diameters, wall area (WA), percentage of the wall area (WA%), wall thickness (WT), and WT/D ratio (BWT). We found no significant correlations between airway wall thickness and spirometric parameters in either group. In the asthma group, the relationships between WA% and BWT, on the one side, and postbronchodilator residual volume, on the other, were noted (r=0.72; P<0.05 and r=0.72; P<0.05, respectively). In the COPD group, WA% related with airway resistance (r=0.72; P<0.05). The correlations between WA% and PC(20) (r=-0.61; P<0.05) and BWT and PC(20) (r=-0.72; P<0.05) were found in the COPD group. There was also a relationship between WA% and airway resistance (Raw) (r=0.72; P<0.05) and BWT and Raw (r=0.45; P=0.1). The number of pack-years correlated with WA and WT in COPD patients. In conclusion, the study shows that the thickening of airway wall in asthma is reflected by an increase in the indices of air trapping and in COPD this thickening results in a higher airway resistance and responsiveness. In COPD, the thickening of airway wall also is related to exposure to tobacco smoke. PMID:20134043

Kosciuch, J; Krenke, R; Gorska, K; Zukowska, M; Maskey-Warzechowska, M; Chazan, R

2009-11-01

380

Does mechanical massage of the abdominal wall after colectomy reduce postoperative pain and shorten the duration of ileus? Results of a randomized study  

Microsoft Academic Search

The aim of this study was to determine the effectiveness of mechanical abdominal massage on postoperative pain and ileus after\\u000a colectomy. We hypothesized that parietal abdominal stimulation could counteract induced pain and postoperative ileus, through\\u000a common spinal-sensitive pathways, with nociceptive visceral messages. After preoperative randomization, 25 patients (age 52\\u000a ± 5 years) underwent active mechanical massage by intermittent negative pressure

Isabelle Le Blanc-Louvry; Bruno Costaglioli; Catherine Boulon; Anne-Marie Leroi; Philippe Ducrotte

2002-01-01

381

In Hypertrophic Cardiomyopathy Reduction of Relative Resting Myocardial Blood Flow Is Related to Late Enhancement, T2-Signal and LV Wall Thickness  

PubMed Central

Objectives To quantify resting myocardial blood flow (MBF) in the left ventricular (LV) wall of HCM patients and to determine the relationship to important parameters of disease: LV wall thickness, late gadolinium enhancement (LGE), T2-signal abnormalities (dark and bright signal), LV outflow tract obstruction and age. Materials and Methods Seventy patients with proven HCM underwent cardiac MRI. Absolute and relative resting MBF were calculated from cardiac perfusion MRI by using the Fermi function model. The relationship between relative MBF and LV wall thickness, T2-signal abnormalities (T2 dark and T2 bright signal), LGE, age and LV outflow gradient as determined by echocardiography was determined using simple and multiple linear regression analysis. Categories of reduced and elevated perfusion in relation to non- or mildly affected reference segments were defined, and T2-signal characteristics and extent as well as pattern of LGE were examined. Statistical testing included linear and logistic regression analysis, unpaired t-test, odds ratios, and Fisher’s exact test. Results 804 segments in 70 patients were included in the analysis. In a simple linear regression model LV wall thickness (p<0.001), extent of LGE (p<0.001), presence of edema, defined as focal T2 bright signal (p<0.001), T2 dark signal (p<0.001) and age (p?=?0.032) correlated inversely with relative resting MBF. The LV outflow gradient did not show any effect on resting perfusion (p?=?0.901). Multiple linear regression analysis revealed that LGE (p<0.001), edema (p?=?0.026) and T2 dark signal (p?=?0.019) were independent predictors of relative resting MBF. Segments with reduced resting perfusion demonstrated different LGE patterns compared to segments with elevated resting perfusion. Conclusion In HCM resting MBF is significantly reduced depending on LV wall thickness, extent of LGE, focal T2 signal abnormalities and age. Furthermore, different patterns of perfusion in HCM patients have been defined, which may represent different stages of disease.

Hueper, Katja; Zapf, Antonia; Skrok, Jan; Pinheiro, Aurelio; Goldstein, Thomas A.; Zheng, Jie; Zimmerman, Stefan L.; Kamel, Ihab R.; Abraham, Roselle; Wacker, Frank; Bluemke, David A.; Abraham, Theodore; Vogel-Claussen, Jens

2012-01-01

382

Left Ventricular Wall Thickness and Regional Systolic Function in Patients With Hypertrophic Cardiomyopathy. A Three-dimensional Tagged Magnetic Resonance Imaging Study  

PubMed Central

Background Regional performance of the hypertrophied left ventricle (LV) in hypertrophic cardiomyopathy (HCM) is still incompletely characterized with studies variably reporting that the hypertrophied myocardium is hypokinetic, akinetic, or has normal function. Different imaging modalities (M-mode or two-dimensional echocardiography) and methods of analysis (fixed or floating frame of reference for wall motion analysis) yield different results. We assessed regional function in terms of systolic wall thickening and shortening and related these parameters to end-diastolic thickness using tagged magnetic resonance imaging and the three-dimensional volume-element approach. Methods and Results In 17 patients with HCM and 6 healthy volunteers, four parallel short-axis images with 12 radial tags and two mutually orthogonal long-axis images with four parallel tags were obtained at end diastole and end systole. After the LV endocardial and epicardial borders were traced, three-dimensional volume elements were constructed by connecting two matched planar segments in two adjacent short-axis image planes, accounting for translation, twist, and long-axis shortening. A total of 72 such volume elements encompassed the entire LV. From each of these elements, end-diastolic thickness and systolic function (fractional thickening and circumferential shortening) were calculated. The average end-diastolic thickness was 15.8±4.2 mm in patients with HCM, which was significantly greater than that in healthy subjects (8.6±2.1 mm, P<.001). Fractional thickening was significantly less in patients with HCM than in healthy subjects (0.31±0.22 versus 0.56±0.23, P<.001). There was a highly significant inverse correlation between fractional thickening and end-diastolic thickness that was independent of the type of hypertrophy or age group. Similar inverse relations were observed between circumferential shortening and end-diastolic wall thickness. Conclusions The myocardium in patients with HCM is heterogeneously thickened and the fractional thickening and circumferential shortening of the abnormally thickened myocardium are reduced compared with healthy subjects. The decrease in fractional thickening and shortening is inversely related to the local thickness.

Dong, Sheng-Jing; MacGregor, John H.; Crawley, Adrian P.; McVeigh, Elliot; Belenkie, Israel; Smith, Eldon R.; Tyberg, John V.; Beyar, Rafael

2007-01-01

383

Measurements of core and compressed-shell temperature and density conditions in thick-wall target implosions at the OMEGA laser facility.  

PubMed

A spectroscopic method is discussed to measure core and compressed-shell conditions in thick-wall plastic-shell implosions filled with deuterium and a tracer amount of argon. Simultaneous observation over a broad photon energy range of the argon line emission and the attenuation and self-emission effects of the compressed shell confining the core yields enough information to extract average temperature and density conditions in both core and compressed shell. The spectroscopic analysis also provides an estimate of the target areal density which is an important characteristic of inertial confinement fusion implosions. PMID:21797499

Florido, R; Mancini, R C; Nagayama, T; Tommasini, R; Delettrez, J A; Regan, S P; Yaakobi, B

2011-06-01

384

Development of a Versatile Laser-Ultrasonic System and Application to the Online Measurement for Process Control of Wall Thickness and Eccentricity of Seamless Tubes  

SciTech Connect

A system for the online, non-contact measurement of wall thickness in steel seamless mechanical tubing has been developed and demonstrated at a tubing production line at the Timken Company in Canton, Ohio. The system utilizes laser-generation of ultrasound and laser-detection of time of flight with interferometry, laser-doppler velocimetry and pyrometry, all with fiber coupling. Accuracy (<1% error) and precision (1.5%) are at targeted levels. Cost and energy savings have exceeded estimates. The system has shown good reliability in measuring over 200,000 tubes in its first six months of deployment.

Robert V. Kolarik II

2002-10-23

385

The gender-specific chest wall thickness prediction equations for routine measurements of ²³⁹Pu and ²⁴¹Am within the lungs using HPGE detectors  

Microsoft Academic Search

The current chest wall thickness prediction equation is not applicable to use in routine lung counting measurements for detection of low energy photons (17-60 keV) within the lungs of male and female subjects. The current chest wall thickness prediction equation was derived for the NaI-CsI {open_quotes}phoswich{close_quotes} detection system, which is not the routine detection system in use; the subject position

L. R. Vickers

1996-01-01

386

Effects of cross-linking, capsule wall thickness, and compound hydrophobicity on aroma release from complex coacervate microcapsules.  

PubMed

Microcapsules were produced by complex coacervation with a gelatin-gum acacia wall and medium-chain-triglyceride core. Dry capsules were partially rehydrated and then loaded with model aroma compounds covering a range of volatility, hydrophobicity, and molecular structure. An experimental design was prepared to evaluate the effects of cross-linking, wall/core ratio, and volatile load level on aroma release from capsules in a hot, aqueous environment. The real-time release on rehydration was measured by monitoring the headspace of a vessel containing the capsules to proton transfer reaction mass spectrometry (PTR-MS). Data collected showed no effects of cross-linking or wall/core ratio on volatile release in hot water for any of the volatiles studied. When comparing real-time release of the prepared coacervates to a spray-dried equivalent, there was no difference in the release from hot water but the release was slower when coacervates were added to ambient-temperature water. We found volatile release to be primarily determined by compound partition coefficients (oil/water and water/air) and temperature. PMID:19199587

Leclercq, Segolene; Milo, Christian; Reineccius, Gary A

2009-02-25

387

Abdominal actinomycosis.  

PubMed

Intra-abdominal and extraperitoneal actinomycosis are rare infections, caused by different Actinomyces species. However, they have been diagnosed more frequently in the last ten years. We report three cases of abdominal actinomycosis and a literature review of the last eight years. All three patients were diagnosed by means of histopathologic examination only. In one case, an intrauterine device (IUD) was associated with the infection. Therapy consisted of surgical resection of the inflammatory, infected tissue, and long-term antibiotic therapy. All patients are free of recurrence. Abdominal actinomycosis should be included in the differential diagnosis of an abdominal pathology of insidious onset, especially when an IUD is in place. Even when infection had spread extensively, combined operative and antibiotic therapy cured most of the cases. PMID:14616714

Wagenlehner, F M E; Mohren, B; Naber, K G; Männl, H F K

2003-08-01

388

Survival of Phytophthora cinnamomi as oospores, stromata, and thick-walled chlamydospores in roots of symptomatic and asymptomatic annual and herbaceous perennial plant species.  

PubMed

Studies were conducted to determine how Phytophthora cinnamomi survives during hot and dry Mediterranean summers in areas with limited surviving susceptible hosts. Two Western Australian herbaceous perennials Chamaescilla corymbosa and Stylidium diuroides and one Western Australian annual Trachymene pilosa were collected weekly from a naturally infested site from the Eucalyptus marginata (jarrah) forest from winter to spring and less frequently during summer 2011/2012. Selfed oospores, thick-walled chlamydospores, and stromata of P. cinnamomi were observed in each species. Oospores and thick-walled chlamydospores germinated in planta confirming their viability. This is the first report of autogamy by P. cinnamomi in naturally infected plants. Stromata, reported for the first time for P. cinnamomi, were densely aggregated inside host cells, and germinated in planta with multiple germ tubes with hyphae capable of producing oospores and chlamydospores. Trachymene pilosa was completely asymptomatic, S. diuroides did not develop root lesions but some plants wilted, whilst C. corymbosa remained asymptomatic above ground but lesions developed on some tubers. The presence of haustoria suggests that P. cinnamomi grows biotrophically in some hosts. Asymptomatic, biotrophic growth of P. cinnamomi in some annual and herbaceous perennials and the production of a range of survival structures have implications for pathogen persistence over summer and its management. PMID:23452949

Crone, Michael; McComb, Jen A; O'Brien, Philip A; Hardy, Giles E St J

2013-02-01

389

Novel technique for full-thickness resection of gastric malignancy: feasibility of nonexposed endoscopic wall-inversion surgery (news) in porcine models.  

PubMed

Full-thickness resection for gastric malignancy carries a risk of peritoneal dissemination due to opening of the gastric lumen. We evaluated the feasibility and safety a novel method of full-thickness resection without transmural communication, called nonexposed endoscopic wall-inversion surgery in ex vivo and in vivo porcine models. Six explanted porcine stomachs and 6 live pigs were used for this study. After marking and submucosal injection around 3 cm simulated lesions, the seromuscular layer was laparoscopically cut and sutured with the lesion inverted to the inside. Consecutively, a mucosubmucosal incision was made endoscopically. Three pigs used for the survival study were monitored for 7 days. All 12 lesions were successfully resected en bloc without perforation. The 3 pigs survived for 1 week without adverse events, and necropsy revealed neither leakage nor abscess formation related to the operation. We demonstrated nonexposed endoscopic wall-inversion surgery to be technically feasible and safe in both ex vivo and in vivo porcine studies. PMID:24300935

Mitsui, Takashi; Goto, Osamu; Shimizu, Nobuyuki; Hatao, Fumihiko; Wada, Ikuo; Niimi, Keiko; Asada-Hirayama, Itsuko; Fujishiro, Mitsuihiro; Koike, Kazuhiko; Seto, Yasuyuki

2013-12-01

390

Analysis of thermal residual stress in a thick-walled ring of Duralcan-base Al-SiC functionally graded material  

SciTech Connect

A ring-cutting test and an elastic theory were applied to evaluate the macroscopic residual stress in a thick-walled ring made of Al-SiC functionally graded material (FGM). The FGM ring specimens, with outer diameter 90 mm, radial thickness approximately 8.4 to 10 mm, and width 30 mm, were fabricated by the centrifugal casting method from an ingot of Duralcan F3D.20S of Al-20 vol pct SiC master composite. Because of a difference in centrifugal forces of SiC particles and of molten aluminum alloy, the rings had a graded composition of SiC particles in the radial direction. The volume fractions of SiC particles in each ring specimen varied in the range of 0 to 43 vol pct from the inner to the outer surface of the ring, depending on the applied mold spin speed. A ring diametral compression test was performed to validate an analytical formula based on the curved beam theory that can account for the graded properties of the material. Excellent agreement between the theory that can account for the graded properties of the material. Excellent agreement between the theory and the experiment was found. The residual stress was found to be generated by a cooling of {Delta}T = 140 K, which was from half the melting point corresponding stress-free condition to the ambient temperature. The hoop residual stresses in the FGM ring varied in the range of {minus}50 to +35 MPa and from tension at the inner surface to compression at the outer space because of the graded composition. With an increase in wall thickness and/or composition gradation, the residual stresses were found to increase.

Fukui, Yasuyoshi [Kagoshima Univ. (Japan). Dept. of Mechanical Engineering; Watanabe, Yoshimi [Shinshu Univ., Ueda (Japan). Faculty of Textile Science and Technology

1996-12-01

391

Analysis of thermal residual stress in a thick-walled ring of duralcan-base Al-SiC functionally graded material  

NASA Astrophysics Data System (ADS)

A ring-cutting test and an elastic theory were applied to evaluate the macroscopic residual stress in a thick-walled ring made of Al-SiC functionally graded material (FGM). The FGM ring specimens, with outer diameter 90 mm, radial thickness approximately 8.4 to 10 mm, and width 30 mm, were fabricated by the centrifugal casting method from an ingot of Duralcan F3D.20S of Al-20 vol pct SiC master composite. Because of a difference in centrifugal forces of SiC particles and of molten aluminum alloy, the rings had a graded composition of SiC particles in the radial direction. The volume fractions of SiC particles in each ring specimen varied in the range of 0 to 43 vol pct from the inner to the outer surface of the ring, depending on the applied mold spin speed. A ring diametral compression test was performed to validate an analytical formula based on the curved beam theory that can account for the graded properties of the material. Excellent agreement between the theory and the experiment was found. The residual stress was found to be generated by a cooling of ? t=140 K, which was from half the melting point corresponding stress-free condition to the ambient temperature. The hoop residual stresses in the FGM ring varied in the range of -50 to +35 MPa and from tension at the inner surface to compression at the outer surface because of the graded composition. With an increase in wall thickness and/or composition gradation, the residual stresses were found to increase.

Fukui, Yasuyoshi; Watanabe, Yoshimi

1996-12-01

392

Fibrolipomas masquerading as abdominal hernias.  

PubMed

A 15-year-old Caucasian girl presented to her general practitioner with a tender, irreducible mass in the paraumbilical region. On examination, two small masses could be felt. She was referred to general surgery. Ultrasound imaging and MRI were unremarkable. However, clinical suspicion suggested multiple areas of abdominal wall herniation. The patient was admitted for elective surgery to exclude herniation. At operation, three subcutaneous masses were found but with no evidence of abdominal wall herniation. Histopathology results from the specimens showed mature adipose tissue mixed with fibrous deposits. There was no evidence of malignancy. A diagnosis of fibrolipoma was given. PMID:24343803

Watson, Hannah Isabella; Saunders, Andrew John

2013-01-01

393

The analysis of time-dependent creep in FGPM thick walled sphere under electro-magneto-thermo-mechanical loadings  

NASA Astrophysics Data System (ADS)

Time-dependent creep response of a smart sphere made of functionally graded piezoelectric material (FGPM) is investigated. The vessel is subjected to an internal pressure, a uniform temperature field, an electric potential and a uniform magnetic field. Under such a loading condition initial elastic stresses are locked in the vessel at zero time. Due to high temperature, creep evolution causes stress redistribution in the sphere which is followed by electric potential redistribution across the thickness of the sphere. History of radial stresses is always reflected by history of electric potential which can be used for condition monitoring of the smart sphere. From the initial elastic stresses it has been found that imposing an electric potential decreases effective stresses. It has also been concluded from history of electric potential that electric potential redistribution is decreasing due to creep evolution and therefore this is followed by increasing effective stresses.

Loghman, A.; Moradi, M.

2013-08-01

394

Steam-assisted crystallization of TPA{sup +}-exchanged MCM-41 type mesoporous materials with thick pore walls  

SciTech Connect

Highlights: ? Mesoporous Ti-containing silica with thicker pore walls was synthesized. ? Ion-exchange and steam-assisted crystallization led to MCM-41/MFI composite. ? The introduction of Ti inhibited the formation of separated MFI particles. ? Lower temperature favored retaining mesoporous characteristics and morphology. -- Abstract: Hierarchical MCM-41/MFI composites were synthesized through ion-exchange of as-made MCM-41 type mesoporous materials with tetrapropylammonium bromide and subsequent steam-assisted recrystallization. The obtained samples were characterized by powder X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis, FT-IR, {sup 1}H–{sup 13}C CP/MAS and nitrogen adsorption–desorption. The XRD patterns show that the MCM-41/MFI composite possesses both ordered MCM-41 phase and zeolite MFI phase. SEM and TEM images indicate that the recrystallized materials retained the mesoporous characteristics and the morphology of as-made mesoporous materials without the formation of bulky zeolite, quite different from the mechanical mixture of MCM-41 and MFI structured zeolite. Among others, lower recrystallization temperature and the introduction of the titanium to the parent materials are beneficial to preserve the mesoporous structure during the recrystallization process.

Chen, Hong Li; Zhang, Kun [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062 (China)] [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062 (China); Wang, Yi Meng, E-mail: ymwang@chem.ecnu.edu.cn [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062 (China)

2012-07-15

395

A new multichannel time reversal focusing method for circumferential Lamb waves and its applications for defect detection in thick-walled pipe with large-diameter.  

PubMed

This paper proposes a new multichannel time reversal focusing (MTRF) method for circumferential Lamb waves which is based on modified time reversal algorithm and applies this method for detecting different kinds of defects in thick-walled pipe with large-diameter. The principle of time reversal of circumferential Lamb waves in pipe is presented along with the influence from multiple guided wave modes and propagation paths. Experimental study is carried out in a thick-walled and large-diameter pipe with three artificial defects, namely two axial notches on its inner and outer surface respectively, and a corrosion-like defect on its outer surface. By using the proposed MTRF method, the multichannel signals focus at the defects, leading to the amplitude improvement of the defect scattered signal. Besides, another energy focus arises in the direct signal due to the partial compensation of dispersion and multimode of circumferential Lamb waves, alongside the multichannel focusing, during MTRF process. By taking the direct focus as a time base, accurate defect localization is implemented. Secondly, a new phenomenon is exhibited in this paper that defect scattered wave packet appears just before the right boundary of truncation window after time reversal, and to which two feasible explanations are given. Moreover, this phenomenon can be used as the theoretical basis in the determination of defect scattered waves in time reversal response signal. At last, in order to detect defects without prior knowing their exact position, a large-range truncation window is used in the proposed method. As a result, the experimental operation of MTRF method is simplified and defect detection and localization are well accomplished. PMID:24877582

Liu, Zenghua; Xu, Qinglong; Gong, Yu; He, Cunfu; Wu, Bin

2014-09-01

396

Abdominal Aortic Aneurysms: Treatments  

MedlinePLUS

... Minimally Invasive Treatments Snapshots Multimedia Multimedia Archive Abdominal Aortic Aneurysms Interventional Radiologists Treat Abdominal Aneurysms Nonsurgically Interventional radiologists ...

397

Unexpected multiple intra-abdominal injuries after projectile fragmentation: report of three cases.  

PubMed

Explosives create and energize particles that act as projectiles prone to further fragmentation or create other secondary missiles in the body. These fragments may result in secondary injuries. This has been repeatedly described in the orthopedic and neurosurgical literature. We report the same process for abdominal injuries after fascial penetration in the military setting. This is an observational case series study. Local wound exploration as a standard approach was performed in conscious patients who sustained abdominal wall injuries. Patients with negative physical examination were excluded from the study. An intraperitoneal injury was assumed in those with a full-thickness fascial defect, and laparotomy was performed. Twenty patients met the study eligibility criteria. Of those 20 patients, 12 had negative wound exploration and were excluded from the study, while abdominal organ injuries were found in eight (40%) patients. During laparotomy, projectile-induced injuries in a sprayed distribution were found in three (38%) of these patients. These injuries were far from the predictable trajectory and in the absence of bone fragmentation. The overall mean number of peritoneal defects was 1.7, and a mean 6.8 intra-abdominal injuries for each peritoneal defect were found when through-and-through injuries were excluded.Despite a single peritoneal defect, there may be multiple intraperitoneal injuries due to further fragmentation of the projectile. Under mass casualties, wound exploration with a full-thickness fascial defect could serve as an indicator of possible intra-abdominal injuries, and consequently indicate exploratory laparotomy. PMID:23588915

Unlü, Aytekin; Petrone, Patrizio; Kar??da?, Tamer; Asensio, Juan A

2012-11-01

398

Abdominal Compartment Syndrome, Abdominal Decompression, and Temporary Abdominal Closure  

Microsoft Academic Search

\\u000a Intra-abdominal hypertension (IAH) and the abdominal compartment syndrome are life-threatening complications in severely injured\\u000a patients. They may trigger a multiple organ dysfunction syndrome with subsequent fatal outcome. Early identification of high-risk\\u000a patients, close monitoring including repeated measuring of intra-abdominal pressure (IAP), and early or even prophylactic\\u000a surgical decompression of the abdomen may effectively lower morbidity and mortality. Following abdominal decompression,

Christoph Meier

399

Effects of the changes in the wall shear stresses (WSS) acting on endothelial cells (EC) during the enlargement of Abdominal Aortic Aneurysms (AAA)  

NASA Astrophysics Data System (ADS)

The changes in the spatial and temporal distribution of the WSS and gradients of WSS during the enlargement of AAAs are important to understand the etiology and progression of this vascular disease, since they affect the wall structural integrity, primarily via the changes induced on the shape, functions and metabolism of the endothelial cells. PIV measurements were performed in aneurysm models, while changing systematically their size and geometry. Two regions with distinct patterns of WSS were identified. The region of flow detachment extends over the proximal half and is characterized by oscillatory WSS of very low mean. The region of flow reattachment, located distally, is dominated by large, negative WSS and sustained gradients of WSS that result from the impact of the vortex ring on the wall. Cultured EC were subjected to these two types of stimuli in vitro. The permeability of the endothelium was found to be largely increased in the flow detachment region. Endothelium cell-cell adhesion, proliferation and apoptosis were also affected by the high gradients of WSS.

Salsac, Anne-Virginie

2005-03-01

400

On the influence of patient-specific material properties in computational simulations: a case study of a large ruptured abdominal aortic aneurysm.  

PubMed

Patient-specific modelling of abdominal aortic aneurysm has been shown to have clinical potential. This paper examines a large ruptured abdominal aortic aneurysm where the tissue from the diseased wall and the intraluminal thrombus was excised during open surgical repair and experimentally characterised. The mechanical data were used to develop material parameters that were incorporated into finite element models with measured nonuniform wall thickness. Implementation of the material data into the numerical model increased peak wall stress by 67%, wall strain by 320% and displacement by 177%, when compared with simulations based on material properties available in the literature. Distributions of numerical results were similar for both material data. Magnitudes of numerical results can differ significantly when using patient-specific material properties and therefore, care should be taken when interpreting numerical results derived from population-based data. PMID:23345202

Doyle, Barry J; Callanan, Anthony; Grace, Pierce A; Kavanagh, Eamon G

2013-02-01

401

Abdominal tuberculosis.  

PubMed Central

Tuberculosis has staged a global comeback and forms a dangerous combination with AIDS. The abdomen is one of the common sites of extrapulmonary involvement. Patients with abdominal tuberculosis have a wide range and spectrum of symptoms and signs; the disease is therefore a great mimic. Diagnosis, mainly radiological and supported by endoscopy, is difficult to make and laparotomy is required in a large number of patient. Management involves judicious combination of antitubercular therapy and surgery which may be required to treat complications such as intestinal obstruction and perforation. The disease, though potentially curable, carries a significant morbidity and mortality. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13

Kapoor, V. K.

1998-01-01

402

Carotid wall elastography to assess midterm vascular dysfunction secondary to intrauterine growth restriction: feasibility and comparison with standardized intima-media thickness.  

PubMed

Several studies have suggested that intrauterine growth restriction (IUGR) increases the risk of cardiovascular disease and early atherosclerosis. Early detection of arteriopathy is essential to early intervention. Although arterial intima-media thickness (IMT) is considered an index of subclinical atherosclerosis in the adult, its validity in pediatric patients may be limited. We have recently introduced a novel imaging-based biomarker (ImBioMark) to assess intrinsic mechanical features of the arterial wall from B-mode ultrasound data. The aim of the work described here was to evaluate the potential of ImBioMark in investigation of cardiovascular health status at the level of the common carotid artery (CCA) in adolescents born after IUGR. We also compared ImBioMark results with automated IMT measurements, a well-established biomarker used in clinical practice and research. The potential sequelae of IUGR on the CCA were examined in a group of adolescents in comparison with healthy controls. Patients with IUGR (n = 7) were 13.85 ± 0.46 y old; the healthy controls (n = 7) were 14.58 ± 0.80 y old (p = 0.058). Cine loops of the CCA B-mode data were digitally recorded, and the arterial elastic modulus was estimated a posteriori with ImBioMark. IMT of the CCA was automatically calculated using QLAB software (Philips, Andover, MA, USA). All patients had been evaluated in utero in our fetal echocardiographic laboratory. ImBioMark detected a significant increase in CCA stiffness in patients with IUGR as compared with healthy controls: elastic modulus = 90.74 ± 11.86 versus 61.30 ± 15.94 kPa, respectively (p = 0.002). There was, however, no significant difference between patients with IUGR and controls in IMT (0.483 ± 0.067 versus 0.476 ± 0.051 mm, respectively, p = 0.831). The impact of IUGR on CCA wall dynamics was confirmed by ImBioMark. The apparent limitation of IMT measurement in this cohort may be the result of geometric arterial changes, that is, the expected thickening, below the level of detection at this age. As early detection of vascular modulation is essential to early intervention in a population at risk, we now intend to extend ImBioMark to investigate larger pathologic cohorts with various degrees of arteriopathy. PMID:24495436

Maurice, Roch L; Vaujois, Laurence; Dahdah, Nagib; Chibab, Najat; Maurice, Anika; Nuyt, Anne-Monique; Lévy, Emile; Bigras, Jean-Luc

2014-05-01

403

Gastric tonometry and direct intraabdominal pressure monitoring in abdominal compartment syndrome  

Microsoft Academic Search

Background\\/Purpose: Abdominal compartment syndrome (ACS) may complicate abdominal closure in patients with abdominal wall defects, abdominal trauma, intraperitoneal bleeding, and infection. Increased intraabdominal pressure (IAP) leads to respiratory compromise, organ hypoperfusion, and a high mortality rate. This study evaluates the efficacy of continuous direct monitoring of IAP and gastric tissue pH in detecting impending ACS. Methods: Ten mongrel puppies weighing

S. A. Engum; B. Kogon; E. Jensen; J. Isch; C. Balanoff; J. L. Grosfeld

2002-01-01