The motion of a neutrally buoyant particle of an elliptic shape in two dimensional shear flow: a numerical study

In this paper, we investigate the motion of a neutrally buoyant cylinder of an elliptic shape freely moving in two dimensional shear flow by direct numerical simulation. An elliptic shape cylinder in shear flow, when initially being placed at the middle between two walls, either keeps rotating or has a stationary inclination angle depending on the particle Reynolds number $Re=G_r r_a^2/\nu$, where $G_r$ is the shear rate, $r_a$ is the semi-long axis of the elliptic cylinder and $\nu$ is the kinetic viscosity of the fluid. The critical particle Reynolds number $Re_{cr}$ for the transition from a rotating motion to a stationary orientation depends on the aspect ratio $AR=r_b/r_a$ and the confined ratio $K=2r_a/H$ where $r_b$ is the semi-short axis of the elliptic cylinder and $H$ is the distance between two walls. Although the increasing of either parameters makes an increase in $Re_{cr}$, the dynamic mechanism is distinct. The $AR$ variation causes the change of geometry shape; however, the $K$ variation influences the wall effect. The stationary inclination angle of non-rotating slender elliptic cylinder with smaller confined ratio seems to depend only on the value of $Re-Re_{cr}$. An expected equilibrium position of the cylinder mass center in shear flow is the centerline between two walls, but when placing the particle away from the centerline initially, it migrates either toward an equilibrium height away from the middle between two walls or back to the middle depending on the confined ratio and particle Reynolds number.Comment: arXiv admin note: substantial text overlap with arXiv:1209.080

The effects of rear-wheel camber on the kinematics of upper extremity during wheelchair propulsion

BACKGROUND: The rear-wheel camber, defined as the inclination of the rear wheels, is usually used in wheelchair sports, but it is becoming increasingly employed in daily propulsion. Although the rear-wheel camber can increase stability, it alters physiological performance during propulsion. The purpose of the study is to investigate the effects of rear-wheel cambers on temporal-spatial parameters, joint angles, and propulsion patterns. METHODS: Twelve inexperienced subjects (22.3±1.6 yr) participated in the study. None had musculoskeletal disorders in their upper extremities. An eight-camera motion capture system was used to collect the three-dimensional trajectory data of markers attached to the wheelchair-user system during propulsion. All participants propelled the same wheelchair, which had an instrumented wheel with cambers of 0°, 9°, and 15°, respectively, at an average velocity of 1 m/s. RESULTS: The results show that the rear-wheel camber significantly affects the average acceleration, maximum end angle, trunk movement, elbow joint movement, wrist joint movement, and propulsion pattern. The effects are especially significant between 0° and 15°. For a 15° camber, the average acceleration and joint peak angles significantly increased (p < 0.01). A single loop pattern (SLOP) was adopted by most of the subjects. CONCLUSIONS: The rear-wheel camber affects propulsion patterns and joint range of motion. When choosing a wheelchair with camber adjustment, the increase of joint movements and the base of support should be taken into consideration

Leiomyoma of the Urinary Bladder: A Case Report

Leiomyoma of the urinary bladder is a rare tumor and constitutes 35% of benign mesenchymal bladder tumors. Herein, we report a case of leiomyoma of the bladder. A 32-year-old female was incidentally found to have an abnormal bladder mass on abdominal ultrasound during work-up for infertility. Bimanual examination then revealed a mass on the right side near the bladder neck area. On cystoscopic examination, an external compression mass covered with normal bladder mucosa could be seen at the right lateral wall. Computerized tomography revealed a homogeneous solitary tumor protruding into the urinary bladder from the right lateral wall without enlarged lymph nodes. Magnetic resonance imaging showed an intraluminal round mass at the right aspect of the urinary bladder, leading to suspicion of an intramural neurogenic or mesenchymal tumor. Surgical exploration was performed via a lower midline incision and a 5.0 × 4.5 × 2.2 cm mass was excised. The pathologic diagnosis was leiomyoma of the bladder. We discuss the diagnosis and management of leiomyoma of the bladder and briefly review the literature

Impact of Hydronephrosis on Treatment Outcome of Solitary Proximal Ureteral Stone After Extracorporeal Shock Wave Lithotripsy

The purpose of this study was to investigate the impact of hydronephrosis on the treatment outcome of patients with a solitary proximal ureteral stone after extracorporeal shock wave lithotripsy (ESWL). A total of 182 consecutive patients who underwent ESWL for a solitary proximal ureteral stone of between 5 and 20 mm in size in our institution were included in this study. The degree of hydronephrosis was defined by renal ultrasonography. Patient data, stone size, shock wave numbers and shock wave energy were also recorded. Treatment outcome was evaluated 3 months after the first session of ESWL. In multivariate analysis, only the maximal stone length (odds ratio [OR], 0.15; 95% confidence interval [CI], 0.03–0.91; p = 0.04) and the degree of hydronephrosis (OR, 0.40; 95% CI, 0.16–0.98; p = 0.045) were significant predicting factors for stone-free status 3 months after ESWL. For stones ≤ 10 mm, the stone-free rate decreased from 80% in patients with mild hydronephrosis to 56.4% in those with moderate to severe hydro-nephrosis. For stones > 10 mm, the stone-free rate decreased further, from 65.2% in patients with mild hydronephrosis to 33.3% in those with moderate to severe hydronephrosis. In summary, patients with a solitary proximal ureteral stone and a stone > 10 mm, the treatment outcome after ESWL was not good if moderate to severe hydronephrosis was noted on ultrasonography. Alternative treatments, such as ureteroscopic lithotripsy, may be appropriate as initial treatment or after failure of one session of ESWL

An Obesity Paradox of Asian Body Mass Index after Cardiac Surgery: Arterial Oxygenations in Duration of Mechanic Ventilation

Background. Numerous studies have documented an obesity paradox that overweight of Caucasian patients has better prognosis after cardiac surgery. This study is to examine Asian patients’ BMI to see whether an obesity paradox exists in DMV after cardiac surgery. Methods. A retrospective study consisted of 428 patients after cardiac surgery from January 2006 to December 2010 in the medical center of Taiwan. The Asian BMI was divided into 3 groups: under-normal weight patients (; ), overweight patients (BMI 24 to <27; ), and obese patients (; ). Multivariable analysis and paired were used to compare all variables. Results. Overweight patients were significantly associated with the shortest DMV. Under-normal weight patients had significantly better oxygenations of AaDO2 and P/F ratio in the DMV; however, they correlated with the longest DMV, older age, more female, lower LVSV, higher BUN, more dialysis-dependent, and poorer outcomes, namely, 1-year mortality, HAP, reintubation, tracheotomy, and LOS. Conclusions. Asian overweight patients after cardiac surgery have better prognosis. Under-normal weight patients have higher risk factors, longer DMV, and poorer outcomes; even though they have better arterial oxygenations, they seem to need better arterial oxygenations for successful weaning ventilator

Environmental factors associated with the prevalence of animal bites or stings in patients admitted to an emergency department

AbstractBackgroundEnvironmental factors may affect the prevalence of different animal bites; however, this area has not been well studied. The aim of this study was to report in detail on the categories of animals involved in causing bites or stings, patient characteristics, outcomes, and associated environmental factors.MethodsThis prospective study involved patients visiting an emergency department for animal bites or stings from January 2007 to December 2008. Patient demographics, type and severity of injuries, outcomes, and types of offensive animals were recorded on a predefined database. Environmental factors, including season, temperature, precipitation, and relative humidity, were collected. Analyses were undertaken to check the relationship between animal bite/sting injuries and environmental factors.ResultsMammalian bites (65.2%) were the most common, followed by insect stings (24.9%) and reptile bites (7.2%). Dogs (54.3%), bees (12.9%), and snakes (7.0%) were the three most common animals to attack. Most of the injuries were mild, superficial, and located on limbs. Only 5.3% of patients had moderate effects and 1.5% of patients had major effects in outcomes. Poor outcome-related factors included large size of wound (maximum length of wound >3 cm; p = 0.000), wound type (skin defect; p = 0.000), and animal type (reptile bite; p = 0.000). The season in which the most injuries occurred was summer for insects and autumn for reptiles. No significant trend was found for mammals and other animals. We found the highest precipitation and insect bites/stings in June (r = 0.93, p < 0.001), and increased incidence of insect bites/stings in the hot months (r = 0.83, p = 0.001). We also found increased reptile bites in May to June and September to October, which may be associated with a significant change in precipitation (r = 0.78, p = 0.005).ConclusionsThe most common animal bites seen in our emergency department are from mammals, especially dogs. Although most animal bites/stings were superficial and minor, there are risks of major effects on outcome in cases with large wounds or reptile bites. Environmental factors, including the season, temperature, and precipitation, were related to insect and reptile stings/bites

Functional characterization of cellulases identified from the cow rumen fungus Neocallimastix patriciarum W5 by transcriptomic and secretomic analyses

<p>Abstract</p> <p>Background</p> <p><it>Neocallimastix patriciarum</it> is one of the common anaerobic fungi in the digestive tracts of ruminants that can actively digest cellulosic materials, and its cellulases have great potential for hydrolyzing cellulosic feedstocks. Due to the difficulty in culture and lack of a genome database, it is not easy to gain a global understanding of the glycosyl hydrolases (<it>GHs</it>) produced by this anaerobic fungus.</p> <p>Results</p> <p>We have developed an efficient platform that uses a combination of transcriptomic and proteomic approaches to <it>N. patriciarum </it>to accelerate gene identification, enzyme classification and application in rice straw degradation. By conducting complementary studies of transcriptome (Roche 454 GS and Illumina GA IIx) and secretome (ESI-Trap LC-MS/MS), we identified 219 putative <it>GH </it>contigs and classified them into 25 <it>GH</it> families. The secretome analysis identified four major enzymes involved in rice straw degradation: β-glucosidase, endo-1,4-β-xylanase, xylanase B and Cel48A exoglucanase. From the sequences of assembled contigs, we cloned 19 putative cellulase genes, including the <it>GH1</it>, <it>GH3</it>, <it>GH5</it>, <it>GH6</it>, <it>GH9</it>, <it>GH18</it>, <it>GH43 </it>and <it>GH48 </it>gene families, which were highly expressed in <it>N. patriciarum </it>cultures grown on different feedstocks.</p> <p>Conclusions</p> <p>These <it>GH </it>genes were expressed in Pichia pastoris and/or Saccharomyces cerevisiae for functional characterization. At least five novel cellulases displayed cellulytic activity for glucose production. One β-glucosidase (W5-16143) and one exocellulase (W5-CAT26) showed strong activities and could potentially be developed into commercial enzymes.</p

Urinary Stone Analysis of 1,000 Patients in Southern Taiwan

Urolithiasis is a common urologic disease. Stones may occur in the kidney, ureter, or urinary bladder. We collected 1,000 stone samples in the subtropical area of southern Taiwan. Stone components were analyzed by Fourier transform infrared spectroscopy. Mixed components of calcium oxalate and calcium phosphate were the most common form of stones (52.3%), followed by calcium oxalate (27.8%) and calcium phosphate (9.3%). Uric acid stones accounted for 7.6%. Magnesium ammonium phosphate stones accounted for 3.0%. Only one cystine stone was found. In the study of urinary stone formation mechanism and prevention of recurrent urolithiasis, knowing the stone composition is important

Factors enhancing the choice of higher resource commitment entry modes in international new ventures

The choice of entry mode in foreign markets is an important strategic decision with major consequences for the success of international new ventures (INVs). It is generally accepted that these firms choose relatively low-resource commitment entry modes to operate in foreign markets. Nevertheless, some researchers have suggested that higher resource commitment entry modes in foreign markets also seem to be competitive strategies for INVs. In this study, from a marketing/international entrepreneurship interface perspective and focusing on organizational issues, we center our attention on international market orientation as a neglected yet important factor in INVs’ choice of higher resource commitment entry modes in foreign markets. We suggest that an entrepreneurial orientation and the timing of international entry are important correlates to an international market orientation. We also suggest that the international learning effort of INVs through their international market orientation has a direct, positive impact on the resources these companies commit to their foreign markets through the use of higher resource commitment entry modes. Accordingly, the model proposes a positive effect of entrepreneurial orientation and early international entry on international market orientation which, in turn, is positively related to higher resource commitment entry modes. The hypotheses were tested on country-level data from Spain, using a structural equation model to analyze relationships between the latent variables. This study extends previous international entrepreneurship research, including insights on antecedents of international new ventures’ choice of resource commitment entry modes in foreign markets. The paper also goes further than previous international entrepreneurship research, by addressing the strategic consequences of rapid entry into foreign markets. Additionally, the results of this work encourage international entrepreneurs to look beyond the explicit value of experiential market knowledge to realize the potential value of international market orientation as an antecedent to higher resource commitment entry modes