bluuebunny/crossref_metadata_2025 huggingface dataset:
Geometric Model and Elastic Constant Prediction of 3D Four-Step Braided Composites Based on the Cubic Spline Curve
Authors: Ni Chenbing , Wei Gaofeng
Published: April 2016

In this paper, the three-dimensional (3D) four-step ([Formula: see text]) rectangular braided composites are analyzed, the internal yarn spatial topology and mechanical model are determined, a new geometric model, which uses a cubic spline curve to fit yarn trajectory, is presented. The new geometric model can be divided into three types of unit cell models which are the interior, surface and corner unit cell. Based on the new proposed geometric model and the stiffness averaging theory, the corresponding elastic constants are predicted. The predicted numerical results are calculated, and compared with the experimental results. Numerical examples indicate that the numerical calculations well agree with the experimental results. Error values between numerical calculations and experimental results are less than 7.5%. The numerical results verify the validity and accuracy of the new geometrical model.
An Accelerated Explicit Method and GPU Parallel Computing for Thermal Stress and Welding Deformation of Automotive Parts
Authors: Ma Ninshu , Yuan Shijian
Published: April 2016

An accelerated explicit method and GPU parallel computing program of finite element method (FEM) are developed for simulating transient thermal stress and welding deformation in large scale models. In the accelerated explicit method, a two-stage computation scheme is employed. The first computation stage is based on a dynamic explicit method considering the characteristics of the welding mechanical process by controlling both the temperature increment and time scaling parameter. In the second computation stage, a static equilibrium computation scheme is implemented after thermal loading to obtain a static solution of transient thermal stress and welding deformation. It has been demonstrated that the developed GPU parallel computing program has a good scalability for large scale models of more than 20 million degrees of freedom (DOFs). The validity of the accelerated explicit method is verified by comparing the transient thermal deformation and residual stresses with those computed by the implicit FEM and experimental measurements. Finally, the thermal stress and strain in an automotive engine cradle model with more than 12 million DOFs were efficiently computed and the results are discussed.
Viscoelastically Supported Viscous Mass Damper Incorporated into a Seismic Isolation System
Authors: Chen Zhao , Junya Kikuchi , Masahiro Ikenaga , Kohju Ikago , Norio Inoue
Published: April 2016

This work discusses the application of a two-node apparent mass device, designated as an inerter, which generates inertial resistance forces proportional to relative accelerations between its two nodes, to seismic isolated civil structures. This study employs a viscous mass damper (VMD) consisting of an inerter and a viscous element in parallel arrangement. Although the use of a VMD is effective in reducing relative responses, previous studies have experienced excessive floor response accelerations because the inerter directly transmits ground accelerations to the superstructure. This work examines the acceleration reduction effect of a viscoelastic element arranged in series to the VMD for filtering out the higher frequency components of the ground motion accelerations.
Needle Tracking and Deflection Prediction for Robot-Assisted Needle Insertion Using 2D Ultrasound Images
Authors: Waine Michael , Rossa Carlos , Sloboda Ron , Usmani Nawaid , Tavakoli Mahdi
Published: April 2016

In many types of percutaneous needle insertion surgeries, tissue deformation and needle deflection can create significant difficulties for accurate needle placement. In this paper, we present a method for automatic needle tracking in 2D ultrasound (US) images, which is used in a needle–tissue interaction model to estimate current and future needle tip deflection. This is demonstrated using a semi-automatic needle steering system. The US probe can be controlled to follow the needle tip or it can be stopped at an appropriate position to avoid tissue deformation of the target area. US images are used to fully parameterize the needle-tissue model. Once the needle deflection reaches a pre-determined threshold, the robot rotates the needle to correct the tip’s trajectory. Experimental results show that the final needle tip deflection can be estimated with average accuracies between 0.7[Formula: see text]mm and 1.0[Formula: see text]mm for insertions with and without rotation. The proposed method provides surgeons with improved US feedback of the needle tip deflection and minimizes the motion of the US probe to reduce tissue deformation of the target area.
An Immersive Virtual Reality Environment for Diagnostic Imaging
Authors: King Franklin , Jayender Jagadeesan , Bhagavatula Sharath K. , Shyn Paul B. , Pieper Steve , Kapur Tina , Lasso Andras , Fichtinger Gabor
Published: April 2016

Purpose: Advancements in and adoption of consumer virtual reality (VR) are currently being propelled by numerous upcoming devices such as the Oculus Rift. Although applications are currently growing around the entertainment field, wide-spread adoption of VR devices opens up the potential for other applications that may have been unfeasible with past implementations of VR. A VR environment may provide an equal or larger screen area than what is provided with the use of multiple conventional displays while remaining comparatively cheaper and more portable making it an attractive option for diagnostic radiology applications. Methods A VR application for the viewing of multiple image slices was designed using: the Oculus Rift head-mounted display (HMD), Unity, and 3D Slicer. Volumes loaded within 3D Slicer are sent to a Unity application that proceeds to render a scene for the Oculus Rift HMD. Users may interact with the images adjusting windowing and leveling using a handheld gamepad controller. Multiple images may be brought closer to the user for detailed inspection. Results Application usage was demonstrated with the simultaneous visualization of longitudinal slices of a serial CT scan of a patient with a lung nodule. Pilot studies for validating usage of the VR system for differential diagnosis and remote collaboration were performed. Initial results suggest that using the VR system increased both task load and time taken to complete tasks, however, the resulting accuracy in assessing nodule growth of nodules was not significantly different than that achieved using a DICOM viewer application on a traditional display.
Three-Dimensional Needle Steering Using Automated Breast Volume Scanner (ABVS)
Authors: Abayazid Momen , Moreira Pedro , Shahriari Navid , Zompas Anastasios , Misra Sarthak
Published: April 2016

Robot-assisted and ultrasound-guided needle insertion systems assist in achieving high targeting accuracy for different applications. In this paper, we introduce the use of Automated Breast Volume Scanner (ABVS) for scanning different soft tissue phantoms. The ABVS is a commercial ultrasound transducer used for clinical breast scanning. A preoperative scan is performed for three-dimensional (3D) target localization and shape reconstruction. The ultrasound transducer is also adapted to be used for tracking the needle tip during steering toward the localized targets. The system uses the tracked needle tip position as a feedback to the needle control algorithm. The bevel-tipped flexible needle is steered under ABVS guidance toward a target while avoiding an obstacle embedded in soft tissue phantom. We present experimental results for 3D reconstruction of different convex and non-convex objects with different sizes. Mean Absolute Distance (MAD) and Dice’s coefficient methods are used to evaluate the 3D shape reconstruction algorithm. The results show that the mean MAD values are 0.30[Formula: see text][Formula: see text]0.13[Formula: see text]mm and 0.34[Formula: see text][Formula: see text]0.17[Formula: see text]mm for convex and non-convex shapes, respectively, while mean Dice values are 0.87[Formula: see text]0.06 (convex) and 0.85[Formula: see text]0.06 (non-convex). Three experimental cases are performed to validate the steering system. Mean targeting errors of 0.54[Formula: see text][Formula: see text]0.24, 1.50[Formula: see text][Formula: see text]0.82 and 1.82[Formula: see text][Formula: see text]0.40[Formula: see text]mm are obtained for steering in gelatin phantom, biological tissue and a human breast phantom, respectively. The achieved targeting errors suggest that our approach is sufficient for targeting lesions of 3[Formula: see text]mm radius that can be detected using clinical ultrasound imaging systems.
SpinoTemplate: A Platform for MRI-Guided Spinal Cord Injections
Authors: Squires Alexander , Oshinski John , Lamanna Jason , Tse Zion Tsz Ho
Published: April 2016

Patients with amyotrophic lateral sclerosis have limited treatment options and a 20% survival rate within five years of diagnosis. Small animal models show promise for halting the associated neurodegeneration when cellular therapeutics are delivered to the ventral horn of the spinal cord. A template-based guidance system was developed to facilitate percutaneous injections under MRI guidance to improve upon existing invasive and time-consuming surgical techniques. Procedure duration was 30[Formula: see text]min plus 5[Formula: see text]min per insertion, with a mean error of [Formula: see text][Formula: see text]2[Formula: see text]mm.
Pyoderma Gangrenosum and Autoimmune Chronic Active Hepatitis in a 17‐Year‐Old Female
Authors: Langley Joanne M. , Roberts Eve A. , Ipp Moshe , Laxer Ronald M. , Boxall Lionel , Phillips M. James
Published: April 2016

A 17‐year‐old girl presented with fever, icterus and painful small
nodules on her face and a larger nodular lesion on the left shin. The patient had
fatigue, intermittent jaundice and abdominal pain over the preceding three months.
The nodular lesions ulcerated and had the typical clinical and histopathological appearance
of pyoderma gangrenosum. Although there was no hepatosplenomegaly, serum
aminotransferases and immunoglobulin G were elevated; antismooth muscle antibodies
were detectable. Inflammatory bowel disease was not presenr. Autoimmune
chronic active hepatitis and pyoderma gangrenosum are a rare association and this is
the youngest patient in whom the association has been reported.
Economic Impact of Inflammatory Bowel Disease in Alberta
Authors: Pinchbeck B.R. , Kirdeikis J. , Thomson A.B.R.
Published: April 2016

This paper attempts to estimate the cost of inflammatory bowel disease (IBO) to the health care system of Alberta. In the 1015 patients responding to a questionnaire, two types of direct costs were compared to provincial averages; physicians' fees and hospital costs. Costs were calculated using the Alberta Health Care Insurance Plan prescribed billing races. The 15-to 24-year-old age group exhibited the highest annual physician fees. This was probably due to the high incidence rate of IBD in this group. The mean cost per patient-year for Crohn's disease was estimated to be $4400 and the mean cost for ulcerative colitis was estimated to be $3020; this did not include outpatient laboratory or radiological investigations, and as such represents an underestimation of the total costs to the health care system. However, only a small minority of the patients were using a large majority of the resources: for example, for both Crohn's and ulcerative colitis, 7% of the patients accounted for 69% of hospital days. The average hospital and physician associated costs declined markedly with duration of the disease. It is estimated that the future cost of IBO to the provincial health care system (the percentage of the provincial health care budget used to diagnose and treat IBO) will double from 1985 to 2000. This underscores the need for continued and expanded research into the cause and treatment of IBO, and the importance of maintaining a health care system which can respond to the needs of these patients.
Recurrent Gastrointestinal Bleeding in a Man with Osler-Weber-Rendu Syndrome and Intestinal Varices
Authors: Clark Robert N. , Paterson William G. , DaCosta Laurington R. , Beck Ivan T.
Published: April 2016

A patient with Osler-Weber-Rendu disease and idiopathic intestinal varices who presented with recurrent gastrointestinal hemorrhage and iron deficiency anemia is reported. The unique coexistence of these two rare disorders is discussed and the literature reviewed.
Clinical Experience with Tixocortol Pivalate
Authors: Hanauer Stephen B.
Published: April 2016

Tixocortol pivalate, the 21‐thiol derivative of hydrocortisone. is a
newly synthesized steroid with topical anti‐inflammatory properties but is devoid of
systemic glucocorticoid and mineralocorticoid activities and toxicity. The mechanism
of action appears to be similar to that of other corticosteroids with regard to steroid
binding sites and prostaglandin biosynthesis, however. the disassociation between
local and systemic effects is due to a ′first pass′ liver metabolism and rapid transformation
with in red blood cells. ln both open and controlled studies in patients with
acute or recurrent distal colitis, clinical efficacy has been noted at doses of 250 mg to
1000 mg in 100 ml solution without an effect on scrum cortisol levels or blood
chemistries. Tixocortol pivalate has consistently shown to be as effective as systemically
absorbed steroids for the treatment of distal ulcerative colitis with out the undesirable
effects associated with currently available steroid preparations.
Acute Bloody Diarrhea with Right Sided Colitis
Authors: Leddin Desmond J. , Barrowman James A.
Published: April 2016

A 50-year-old woman presented with bloody diarrhea and radiological evidence of right sided colitis. EnterohemorrhagicEscherichiacoli was isolated from the stool. The illness subsided spontaneously but was complicated by the development of hypoproteinemia and ascites. This disease presents a variable clinical picture but apparent 'ischemic colitis' in younger patients is especially suggestive of infection with E coli 0157:H7.
Uses and Abuses of Intestinal Permeability Measurements
Authors: Peters Timothy J. , Bjarnason Ingvar
Published: April 2016

Intestinal permeability has been assessed with three different classes of permeability probes, viz various sugar mixtures,51Cr-EDTA and poly(ethylene glycol). The former two methods are having increasing clinical applications in the screening and assessment of small intestinal damage and51Cr-EDTA is now the preferred probe for routine clinical use. Poly(ethylene glycol)s have numerous disadvantages and are not recommended. Probes may be used both in vitro and in vivo and have been applied to a wide variety of clinical problems. In particular, NSAID induced enteropathy, a major complication of the chronic administration of these widely-used drugs, was recognized for the first time with51Cr-EDTA permeability measurements. The cytoprotective role of various prostanoids was also clearly demonstrated using51Cr-EDTA. It is anticipated that measurement of intestinal permeability will play an increasing role in clinical and research investigation and in the monitoring of intestinal disease.
Dietary Sugar and Crohn's Disease
Authors: Heaton K.W.
Published: April 2016

Epidemiologically, Crohn's is a disease of modern Western civilization. The diet of the Western world is highly processed. Many surveys have shown that patients with Crohn's disease habitually eat more than the average amount of some processed foods, namely those rich in added sugars. Sugar rich meals lead to increased intestinal permeability which is a feature of Crohn's disease patients and of their relatives. Replacement of added sugars and fibre depicted cereals by whole or unrefined foods is well tolerated by most patients with Crohn's disease and it may reduce their need for surgery and hospital treatment. Until the pathogenesis of the disease is clarified the role of dietary factors remains debatable but the evidence incriminating a sugar rich highly processed diet in the etiology of Crohn's disease, albeit indirect, is enough to justify further research in this area.
Pitfalls in the Radiological Diagnosis of Inflammatory Bowel Disease
Authors: LeBrun GP
Published: April 2016

Effective management of patients with inflammatory bowel disease (IBD) depends upon accurate diagnosis. The classic radiological features of this group of diseases have been extensively described. In addition, newer modalities such as ultrasound, computed tomography scanning, magnetic resonance imaging and nuclear medicine have been added to the diagnostic armamentarium. In spite of this the patient with IBD often presents a diagnostic dilemma as these conditions may mimic, and be mimicked by, other diseases. In particular, infectious, neoplastic and vascular etiologies should be considered in the differential diagnosis of IBD and suspected especially if the radiological appearances are not typical. Accurate diagnosis requires the selection of radiological examinations appropriate to the clinical situation which must be performed and interpreted with an awareness of the many pitfalls in this type of diagnosis.
Colitis Caused by Escherichia Coli 01587:H7: A Study of Six Cases
Authors: Eidus LB , Guindi M , Drouin J , Gregoire S , Barr JR
Published: April 2016

The clinical and pathologic features of six patients with proven verotoxin-producing Escherichia coli colitis are described. Clinical data, 25 biopsy specimens and two autopsies from these patients are reviewed. All presented with crampy abdominal pain and bloody diarrhea. Colonoscopic findings included edema, erythema, pseudomembranes and hemorrhage. On biopsy, two patients had ischemic colitis, one had pseudomembranous colitis and three had a combination of concurrent ischemic and pseudomembranous colitis. Four cases showed fibrin-platelet thrombi in mucosal capillaries and submucosal arterioles. The classical pattern of infectious colitis was not seen in these cases. Other nonspecific changes included patchy mucosal edema, congestion, focally prominent interstitial hemorrhage and mild, patchy increase of the lymphoplasmocytic component of the lamina. Ischemic necrosis was present in 10 of 25 biopsies (40%), pseudomembranes in seven of 25 biopsies (28%), and four of 25 biopsies (16%) showed both. Colon from one autopsy revealed edema, pseudo membranes and intramural infarction . Concurrent thrombotic thrombocytopenic purpura was clinically documented in three of six patients. It is concluded that, in the context of hemorrhagic colitis, the following observations are indicative of E coli 0157:H7: the combination of pseudomcmbranous and ischemic colitis; ischemic colitis in a young patient; or pseudomembranous colitis with Clostridium difficile-negative culture and toxin. Multiple biopsies are required to demonstrate the full-blown features. E coli 0157:H7 colitis should be added to the differential diagnosis of submucosal edema.
Short Bowel Syndrome: Surgical Therapy
Authors: Buie W Donald , Thurston Olin G , Fedorak Richard N
Published: April 2016

Many surgical solutions to short bowel syndrome have been proposed; however, none has proven to be uniformly successful. Some of these solutions, combined with optimal medical management, may represent the patient's only hope for survival without parenteral nutrition. Most forms of surgical therapy are supportive and aim at controlling three basic pathophysiological defects: decreased intestinal transit time, gastric hypersecretion, and reduced functional mucosal surface area. Conservative resection and, thus, prevention of short bowel syndrome remains the best form of treatment at present. In the future, small bowel transplantation may prove to be an important advance in therapy; however, this remains largely experimental due to continued problems with rejection.
The Equivalence of Two Open Therapeutic Regimens of Cimetidine in the Treatment of Acute Duodenal Ulcer Disease: A Canadian Multicentre Trial
Authors: Navert H , Archambault AP , Cleator IGM , Hershfield NB , Prokipchuk EJ , Thomson ABR
Published: April 2016

One hundred and four patients completed a multicentre study comparing the standard cimetidine regimen of 300 mg qid with cimetidine 600 mg bid in the treatment of acute duodenal ulcer. Both dosage regimens were effective in alleviating symptoms. At the two- and four-week assessments a significantly greater decrease in frequency, duration and severity of night time pain was recorded in the 600 mg bid group (P<0.05). The healing rates were equivalent in both treatment groups. After eight weeks of treatment, 96% of the patients had healed in each treatment group. Cimetidine 600 mg bid may represent a useful alternative therapeutic regimen to the standard 300 mg qid dosage in patients with symptomatic acute duodenal ulcer disease.
Laser Lithotripsy — The New Wave
Authors: Hochberger J , Ell C
Published: April 2016

Currently more than 90% of all common bile duct concrements can he removed via the endoscopic retrograde route by means of endoscopic papillotomy, stone extraction by baskets and balloon catheters, or mechanical lithotripsy. Oversized, very hard or impacted stones however often st ill resist conventional endoscopic therapy. Laser lithotripsy represents a promising new endoscopic approach to the nonsurgical treatment of those common bile duct stones. Currently only short-pulsed laser systems with high power peaks but low potential for thermal tissue damage are used for stone fragmentation. Systems in clinical applications are the pulsed free-running-mode neodymium YAG (Nd:YAG) laser (1064 nm, 2 ms) and the dye laser (504 nm, 1 to 1.5 μs). Energy transmission via highly flexible 200 ìm quartz fibres allows an endoscopic retrograde approach to the stone via conventional duodenoscope or mother-baby-scope systems. New systems currently in preclinical and first clinical testing are the Q-switched Nd:YAG laser (1064 nm, 20 ns) and the Alexandrite laser (700 to 815 nm, 30 to 500 ns). By means of extremely short nanosecond pulses (10-9s) for the induction of local shock waves at the stone surface, possible tissue damage is even more reduced. No complications have been reported so far after applying laser lithotripsy clinically in about 120 patients worldwide. Compared to extracorporeal shock wave treatment, laser lithotripsy can be executed in any endoscopy unit in the scope of the endoscopic pretreatment and does not require general anesthesia, which is often necessary for extracorporeal shock wave lithotripsy.
Review of Endoscopic Thermal Treatment of Peptic Ulcer Hemorrhage
Authors: Sargeant Ian R , Loizou Louis A , Bown Stephen G
Published: April 2016

Peptic ulcer hemorrhage is still an important cause of emergency surgery and death. The overall mortality is around 10% from gastrointestinal bleeding, and most of the preventable deaths occur in elderly patients with continued or recurrent bleeding from peptic ulcers. An effective nonsurgical method of hemostasis has long been recognized to be desirable. However it was only when the 'visible vessel' was recognized as the important risk factor for further bleeding that studies capable of testing new modalities adequately could be performed. Careful washing of the ulcer crater is essential for identification of these visible vessels. An effective endoscopic method was first demonstrated in 1981 in patients with visible vessels treated with argon laser. Many groups have now shown excellent efficacy of neodymium:yttrium-aluminum-garnet (NdYAG) laser in preventing further hemorrhage from ulcers with bleeding and nonbleeding visible vessels. Two controlled prospective studies have demonstrated efficacy of the heater probe, but one well designed study did not. Similar studies with both bipolar and monopolar electrocoagulation have shown significant reductions in rebleeding in patients with visible vessels treated using the chosen modality. More recent studies have achieved excellent results by pre-injection with adrenaline and one repeat endoscopic treatment for rebleeds. A few groups have now reported equally good results with injection alone. Long term follow-up of patients with peptic ulcer hemorrhage has confirmed prolonged hemostasis in groups treated with two thermal modalities and in controls.
Pregnancy and the Biliary System
Authors: Witt Helga , Connon J Joseph
Published: April 2016

Alterations in the synthesis and secretion of bile salts and
cholesterol and in gallbladder function occur during pregnancy. These changes
are related to the effects of estrogen and progesterone. Biliary cholesterol saturation
and the cholic acid/chenodeoxycholic acid ratio increase. Progesterone also
diminishes gallbladder contractility and emptying. Gallstones occur in 2.5 to
11% of pregnant women and are associated with cholecystitis in 0.008 to 0.1%
of pregnant women. Operative treatment should be deferred if possible until after
delivery; failing that, surgery is best done in the second trimester. Endoscopic
pap1llotomy may prove to be the best therapy for choledocholithiasis.
Budesonide Enemas for Topical Therapy of Ulcerative Colitis
Authors: Rutgeerts P
Published: April 2016

Budesonide is a nonhalogenated glucocorticosteroid that is very suitable for topical therapy in left-sided colitis because it has a high ratio of topical to systemic activity. Although it is absorbed, it is very rapidly metabolized by the liver (first pass metabolism). It does not suppress the hypothalamic-pituitary axis. Budesonide has been shown to be more effective than placebo and predinsolone enemas for the treatment of left-sided ulcerative colitis.
Fish Oil in the Treatment of Ulcerative Colitis
Authors: Ó'Moráin C , Tobin A , McColl T , Suzuki Y
Published: April 2016

Patients with active ulcerative colitis have increased levels of leukotriene B4 in their rectal mucosa. Eicosapentaenoic acid (EPA) competitively inhibits the cyclo-oxgenase pathway and reduces the formation of cyclo-oxygenase pathway products. EPA is a good substrate for lipoxygenase enzymes and is efficiently converted to leukotriene 85, which is less biologically active. The conversion of EPA to leukotriene B5 is as efficient as that of arachidonic acid to teukotriene B4. Two pilot studies showed benefit of EPA in the treatment of ulcerative colitis. Two of three controlled studies suggest that EPA is more effective than placebo in the treatment of active chronic ulcerative colitis. The mechanism of action is probably reduction of leukotriene B4, but EPA could increase cell and lysosomal membrane stability, or it may exert its effect by reducing interleukin-l. More controlled studies and detailed investigation into the mode of action of EPA are required.
Intestinal Absorption of Bile Salts
Authors: Madsen Karen
Published: April 2016

Bile acids are secreted from the liver into the duodenum where they aid in the digestion and absorption of dietary lipids. Absorption of bile acids occurs through both ionic and nonionic diffusion in the jejunum and colon and through an active sodium ion-dependent carrier mechanism in the ileum. The prima, y bile acids synthesized in the liver can be converted by intestinal bacteria into secondary and tertiary bile acids. Bile acids may also be conjugated with glycine or taurine which results in an increase in the hydrophilicity and solubility of these compounds at physiological pH. The amount of passive diffusion of bile acids that occurs across the brush border membrane along the length of the entire intestine depends upon the ratio of ionized to nonionized bile acids coupled with the bile salt concentration and the individual permeability coefficients of monomers. Active transport of both conjugated and nonconjugated species of bile acids depends upon the presence of a single negative charge on the side chain. Maximal transport rates for bile acids are related to the number of hydroxyl groups present while the Michaelis-Menten constant for transport is dependent upon whether or not the bile acid is conjugated. Although active uptake of bile acids from the ileum has been considered the major route for bile salt absorption in the small intestine, the mechanism may actually be responsible for only a small proportion of the total bile acid pool absorbed from the lumen.
Six‐Pack Balancing Act: A Conceptual Model for the Intestinal Lining
Authors: Rangachari PK
Published: April 2016

The cells chat form the lining of the intestine belong to a class of
cells termed ′polarized′ or ′asymmetric.′ The membranes surrounding these cells
show functional differences at the luminal and contraluminal surfaces. The cells
line up to form sheets and it is across these sheers that movement of fluids and
solutes occurs. Such movement occurs in both directions across the lining and
the occurrence of diarrhea or constipation depends to a considerable extent upon
the net result of the absorptive and secretory mechanisms and their modulation
by a host of factors such as neurotransmitters, bacterial products, drugs, etc. This
review provides a simple framework for understanding the dynamics of the gut
lining. Diamond′s six‐pack model of epithelia is modified to include the dynamic
tension between absorptive and secretory mechanisms.
Role of Cyclosporine in Crohn's Disease
Authors: Williams CN
Published: April 2016

Cyclosporine A has been shown anecdotally to be useful in Crohn's disease. In most studies, a clinical response is seen within a short time, one to two weeks. A feature common to all studies is frequent relapse shortly after the drug is discontinued. There are problems in dosage and bioavailability with gastrointestinal intolerance, malabsorption and variable absorption. Consequently, there is a requirement for monitoring of blood levels. There is renal toxicity, particularly when prior renal disease is present, when nephrotoxic drugs arc used concomitantly and in the elderly. A prospective, placebo controlled, international trial of cyclosporine A in patients with steroid-resistant Crohn's disease was recently published. All patients in this study had active Crohn's disease (Crohn's disease activity index greater than 150). There were 37 patients randomized to cyclosporine and 34 to placebo. The mean age, proportion with prior surgery, disease location, presence of complications and cotreatment was the same in both groups. At 12 weeks, two-thirds of the patients on cyclosporine A had responded, compared to one-third on placebo. The 'therapeutic gain', defined as "difference in effect between treatments", was significant at two weeks and remained so for one, two and three months. There is a steroid-sparing effect with this drug, as with other immunosuppressives used in Crohn's disease - a valuable side effect of this therapy. There is increasing evidence that in patients with Crohn's disease, cyclosporine A may be malabsorbed. It is, therefore, recommended that all patients be given intravenous cyclosporine for at least the first week. Once the response is present, the drug may be switched to the oral route, and a pharmacokinetic profile performed. The drug may need to be given three or four times a day in some Crohn's disease patients. In children, cyclosporine A absorption appears to be related to the length of the intestine. This has not been determined in adults. Currently, the use of cyclosporine A is limited to patients with steroid-resistant Crohn's disease presenting to tertiary referral centres with appropriate cyclosporine A monitoring facilities.
Pharmacokinetics of 5-Aminosalicylic Acid Enteral Suspension in Crohn's Disease Patients and Normal Volunteers
Authors: Williams CN , Morgan E
Published: April 2016

5-Aminosalicylic acid (5-ASA) is available in many countries in tablet, enema and suppository form. A new enteral suspension was studied in six patients with Crohn's disease affecting the upper gastrointestinal tract and in six healthy volunteers. Four grams of 5-ASA dissolved in 240 ml suspension was given via a nasoduodenal tube over 4 h. Blood was drawn at 0, l, 2, 3, 4, 5, 6, 7, 8, 12 and 24 h, and 24 h urine and stool were collected for 5-ASA and n-acetyl-5-ASA analyses. All patients and subjects tolerated the procedure without problems and no side effects were encountered. All subjects and volunteers had normal renal function before and after the study; serum creatinine and blood urea nitrogen did not change. Urine recovery of 5-ASA ranged from 0.6 to 3.4 g (controls) and 0.46 to 3.6 g (patients). Stool recovery of 5-ASA was 0.1 to 0.3 g (controls) and 0.12 to 0.54 g (patients). There was delayed absorption of 5-ASA in patients compared to controls, shown by time to peak concentrations (4 to 6 h versus 3 h). Predominantly urine excretion of the n-acetyl metabolite occurred in both groups, with less than 12% stool excretion. Continued treatment induced remission. An enteral suspension of 5-ASA may be of benefit in selected patients with proximal small bowel Crohn's disease.
Surgery in Ulcerative Colitis - Return of the Ileorectal Anastomosis
Authors: Leijonmarck Carl-Eric , Hellers Göran
Published: April 2016

The main advantages of ileorectal anastomosis for patients with ulcerative colitis are that it is easier to perform and the complication rate is probably lower than for the pelvic pouch procedure. Ileoreccal anastomosis is, however, not suitable for all patients. Patients with severely inflamed and scarred rectums with low compliance are not suitable candidates for the procedure. With the use of the new steroids, however, the number of patients suitable for ileorectal anastomosis will probably increase. The functional outcome, particularly in terms of continence, is probably better following ileorectal anastomosis than after pelvic pouch. The need for long term cancer surveillance is a problem, but newer methods for surveillance may increase further the possibilities of controlling cancer risk in the future. There seems to be an equal need for future medical surveillance following both surgical procedures. In balance, newer methods of medical therapy and cancer surveillance will probably lead to a return to ileorectal anastomosis in a significant number of patients.
Collagenous Inflammatory Mucosal Diseases of the Gastrointestinal Tract
Authors: Freeman Hugh J
Published: April 2016

A new group of collagenous inflammatory disorders of the gastric
and intestinal mucosa has been described in the past two decades. These entities
appear to be characterized by a distinct histopathologic lesion in the subepithelial
region of the lamina propria. Functional alterations may also occur, presumably
related to collagen deposition and the associated inflammatory process. Collagenous
sprue is characterized by progressive and unrelenting malabsorption; a
lethal outcome has usually been described, possibly reflecting the site of collagen
deposition and the critical role of the small bowel for maintenance of a normal
nutritional state. In contrast, collagenous colitis is characterized by persisting or
episodic watery diarrhea; clinical impairment appears to be less severe but the
entity is not rare, possibly reflecting its colonic localization. Most recently,
collagenous gastritis, possibly accompanied by a functional reduction in acid
secretion and impaired gastric emptying, has been recognized. Further definition
of these entities is still required, particularly in relation to etiology, pathogenesis
and effective therapy.
Gastroptosis: A Cause of Postprandial Abdominal Bloating
Authors: Sullivan Stephen N
Published: April 2016

Ptosis of the food‐ and fluid‐filled stomach is described as an ‘organic’ explanation for postprandial abdominal bloating in six patients. Demographic data, precipitating foods, radiography and gastric emptying times are presented. Therapy with support hose, a girdle, domperidone and cisapride were variously perceived to he helpful.
Granulomatous (Crohn’s) Appendicitis
Authors: Binder Hanna , Freeman Hugh J
Published: April 2016

Four patients with Crohn’s disease limited initially to the appendix, treated by appendectomy and seen at the University of British Columbia Hospital, Vancouver, during 1980-90 are described. In all patients the initial diagnosis was based on the presence of an appendiceal granulomatous inflammatory process, while other causes such as sarcoidosis, tuberculosis and bacterial gut pathogens were excluded. While post appendectomy complications, including enterocutaneous fistula, did not occur, symptomatic recurrence was later observed in three patients four to 24 months following appendiceal resection. This recurrence was associated with a diagnosis of recurrent Crohn’s disease and histological findings of granulomas elsewhere in the gastrointestinal tract. In conclusion, a ‘reagent grade’ population of patients with Crohn’s disease limited to the appendix was seen. A high frequency of recurrent disease was defined, indicating that isolated granulomarous appendicitis may be the initial and sole presenting feature of Crohn’s disease.
Cerbral Venous Thrombosis in Ulcerative Colitis and Review of the Literature
Authors: Chaun Hugh , Beckman Jeff H , Sparling Terence G
Published: April 2016

A 30‐year‐old man with an eight year history of ulcerative colitis developed left occipital headache, mental confusion, dysphasia and right‐sided weakness when his bowel disease was asymptomatic. Investigations revealed thrombosis of the cerebral sagittal sinus and left transverse sinus. The literature relating to cerebrovascular complications associated with ulcerative colitis is reviewed, and the possible pathogenetic mechanisms of venous thrombosis in ulcerative colitis are discussed. The importance of recognizing that venous thrombosis may occur in association with ulcerative colitis in remission is emphasized.
Accurate and Efficient Computations of the Greeks for Options Near Expiry Using the Black-Scholes Equations
Authors: Jeong Darae , Yoo Minhyun , Kim Junseok
Published: April 2016

We investigate the accurate computations for the Greeks using the numerical solutions of the Black-Scholes partial differential equation. In particular, we study the behaviors of the Greeks close to the maturity time and in the neighborhood around the strike price. The Black-Scholes equation is discretized using a nonuniform finite difference method. We propose a new adaptive time-stepping algorithm based on local truncation error. As a test problem for our numerical method, we consider a European cash-or-nothing call option. To show the effect of the adaptive stepping strategy, we calculate option price and its Greeks with various tolerances. Several numerical results confirm that the proposed method is fast, accurate, and practical in computing option price and the Greeks.
The Antibacterial Activity of Chitosan Products Blended with Monoterpenes and Their Biofilms against Plant Pathogenic Bacteria
Authors: Badawy Mohamed E. I. , Rabea Entsar I. , Taktak Nehad E. M. , El-Nouby Mahmoud A. M.
Published: April 2016

This study focuses on the biological activities of eleven chitosan products with a viscosity-average molecular weight ranging from 22 to 846 kDa in combination with the most active monoterpenes (geraniol and thymol), out of 10 tested, against four plant pathogenic bacteria,Agrobacterium tumefaciens,Erwinia carotovora,Corynebacterium fascians, andPseudomonas solanacearum. The antibacterial activity was evaluatedin vitroby the agar dilution technique as a minimum inhibitory concentration (MIC) that was found to be dependent on the type of the microorganism tested. The most active product of chitosan was used for biofilm production enriched with geraniol and thymol (0.1 and 0.5%) and the films were also evaluated against the tested bacteria. The biological bioactivities summarized here may provide novel insights into the functions of chitosan and some monoterpenes and potentially allow their use for food protection from microbial attack.
Bubaline Cholecyst Derived Extracellular Matrix for Reconstruction of Full Thickness Skin Wounds in Rats
Authors: Shakya Poonam , Sharma A. K. , Kumar Naveen , Vellachi Remya , Mathew Dayamon D. , Dubey Prasoon , Singh Kiranjeet , Shrivastava Sonal , Shrivastava Sameer , Maiti S. K. , Hasan Anwarul , Singh K. P.
Published: April 2016

An acellular cholecyst derived extracellular matrix (b-CEM) of bubaline origin was prepared using anionic biological detergent. Healing potential of b-CEM was compared with commercially available collagen sheet (b-CS) and open wound (C) in full thickness skin wounds in rats. Thirty-six clinically healthy adult Sprague Dawley rats of either sex were randomly divided into three equal groups. Under general anesthesia, a full thickness skin wound (20 × 20 mm2) was created on the dorsum of each rat. The defect in group I was kept as open wound and was taken as control. In group II, the defect was repaired with commercially available collagen sheet (b-CS). In group III, the defect was repaired with cholecyst derived extracellular matrix of bovine origin (b-CEM). Planimetry, wound contracture, and immunological and histological observations were carried out to evaluate healing process. Significantly (P<0.05) increased wound contraction was observed in b-CEM (III) as compared to control (I) and b-CS (II) on day 21. Histologically, improved epithelization, neovascularization, fibroplasia, and best arranged collagen fibers were observed in b-CEM (III) as early as on postimplantation day 21. These findings indicate that b-CEM have potential for biomedical applications for full thickness skin wound repair in rats.
XPC Promotes Pluripotency of Human Dental Pulp Cells through Regulation of Oct‐4/Sox2/c‐Myc
Authors: Liu Lu , Peng Zhengjun , Xu Zhezhen , Wei Xi
Published: April 2016

Introduction. Xeroderma pigmentosum group C (XPC), essential component of multisubunit stem cell coactivator complex (SCC), functions as the critical factor modulating pluripotency and genome integrity through interaction with Oct‐4/Sox2. However, its specific role in regulating pluripotency and multilineage differentiation of human dental pulp cells (DPCs) remains unknown. Methods. To elucidate the functional role XPC played in pluripotency and multilineage differentiation of DPCs, expressions of XPC in DPCs with long‐term culture were examined by real‐time PCR and western blot. DPCs were transfected with lentiviral‐mediated human XPC gene; then transfection rate was investigated by real‐time PCR and western blot. Cell cycle, apoptosis, proliferation, senescence, multilineage differentiation, and expression of Oct‐4/Sox2/c‐Myc in transfected DPCs were examined. Results. XPC, Oct‐4, Sox2, and c‐Myc were downregulated at P7 compared with P3 in DPCs with long‐term culture. XPC genes were upregulated in DPCs at P2 after transfection and maintained high expression level at P3 and P7. Cell proliferation, PI value, and telomerase activity were enhanced, whereas apoptosis was suppressed in transfected DPCs. Oct‐4/Sox2/c‐Myc were significantly upregulated, and multilineage differentiation in DPCs with XPC overexpression was enhanced after transfection. Conclusions. XPC plays an essential role in the modulation of pluripotency and multilineage differentiation of DPCs through regulation of Oct‐4/Sox2/c‐Myc.
Navigated Transtubular Extraforaminal Decompression of the L5 Nerve Root at the Lumbosacral Junction: Clinical Data, Radiographic Features, and Outcome Analysis
Authors: Stavrinou P. , Härtl R. , Krischek B. , Kabbasch C. , Mpotsaris A. , Goldbrunner R.
Published: April 2016

Purpose. Extraforaminal decompression of the L5 nerve root remains a challenge due to anatomic constraints, severe level-degeneration, and variable anatomy. The purpose of this study is to introduce the use of navigation for transmuscular transtubular decompression at the L5/S1 level and report on radiological features and clinical outcome.Methods. Ten patients who underwent a navigation-assisted extraforaminal decompression of the L5 nerve root were retrospectively analyzed.Results. Six patients had an extraforaminal herniated disc and four had a foraminal stenosis. The distance between the L5 transverse process and the para-articular notch of the sacrum was 12.1 mm in patients with a herniated disc and 8.1 mm in those with a foraminal stenosis. One patient had an early recurrence and another developed dysesthesia that resolved after 3 months. There was a significant improvement from preoperative to postoperative NRS with the results being sustainable at follow-up. ODI was also significantly improved after surgery. According to the Macnab grading scale, excellent or good outcomes were obtained in 8 patients and fair ones in 2.Conclusions. The navigated transmuscular transtubular approach to the lumbosacral junction allows for optimal placement of the retractor and excellent orientation particularly for foraminal stenosis or in cases of complex anatomy.
Acupuncture Anxiolytic Effects on Physiological and Psychological Assessments for a Clinical Trial
Authors: Shayestehfar Monir , Seif-Barghi Tohid , Zarei Sahar , Mehran Amir
Published: April 2016

In a randomized controlled trial we examined the effect of acupuncture on anxiety of the adolescent football players prior to the competition using psychological and physiological markers. A total of 45 athletes were equally allocated to either acupuncture group, sham group, or wait-list control group. Thereafter, all participants were asked to complete an anxiety questionnaire before and after the intervention. Their heart rate and skin conductance were also examined before and after the intervention. The results of ANOVA on posttest scores showed that acupuncture had a significant effect on cognitive anxiety (p=0.001) and somatic anxiety (p<0.001) but not on self-confidence (p>0.05). Furthermore, the results showed that acupuncture significantly decreased the skin conductance in acupuncture group compared to sham group (p=0.006) and wait-list control group (p<0.001). In conclusion, the results suggested that acupuncture has the capacity to decrease cognitive anxiety and somatic anxiety prior to competition in adolescent athletes, while this was accompanied by significant physiological changes. This trial is registered withIRCT138904074264N1(IRCT is a Primary Registry in the WHO Registry Network).
Error Analysis and Adaptive-Robust Control of a 6-DoF Parallel Robot with Ball-Screw Drive Actuators
Authors: Negahbani Navid , Giberti Hermes , Fiore Enrico
Published: April 2016

Parallel kinematic machines (PKMs) are commonly used for tasks that require high precision and stiffness. In this sense, the rigidity of the drive system of the robot, which is composed of actuators and transmissions, plays a fundamental role. In this paper, ball-screw drive actuators are considered and a 6-degree of freedom (DoF) parallel robot with prismatic actuated joints is used as application case. A mathematical model of the ball-screw drive is proposed considering the most influencing sources of nonlinearity: sliding-dependent flexibility, backlash, and friction. Using this model, the most critical poses of the robot with respect to the kinematic mapping of the error from the joint- to the task-space are systematically investigated to obtain the workspace positional and rotational resolution, apart from control issues. Finally, a nonlinear adaptive-robust control algorithm for trajectory tracking, based on the minimization of the tracking error, is described and simulated.