Evaluation of impact factors of straight and horizontally curved composite concrete deck-steel cellular bridges.

A theoretical investigation of the dynamic impact factors for straight and curved composite cellular bridges is performed in this thesis. The bridges are modelled as three-dimensional solid structures using commercially available software ABAQUS to simulate the bridge geometry and vehicle loading. The vehicle loads are modelled as a pair of two concentrated forces moving along in circumferential paths. Extensive parametric study is conducted, in which 120 composite multi-cell bridge prototypes are analyzed to: (1) evaluate their first natural frequencies; (2) evaluate their impact factors for moment, reaction, and deflection under truck loading conditions. The key parameters considered in this study are: number and area of cross-bracing and top-chord systems, number of cells, number of lanes, degree of curvature, span length, and loading conditions. Based on the data generated from the parametric study, expressions for dynamic impact factors for moment, reaction, and deflection are proposed.* (Abstract shortened by UMI.) *This dissertation includes a CD that is compound (contains both a paper copy and a CD as part of the dissertation). The CD requires the following application: Microsoft Office. Source: Masters Abstracts International, Volume: 41-01, page: 0279. Adviser: John B. Kennedy. Thesis (M.A.Sc.)--University of Windsor (Canada), 2001

Current Applications and Future Directions of Bioengineering Approaches for Bladder Augmentation and Reconstruction

End-stage neurogenic bladder usually results in the insufficiency of upper urinary tract, requiring bladder augmentation with intestinal tissue. To avoid complications of augmentation cystoplasty, tissue-engineering technique could offer a new approach to bladder reconstruction. This work reviews the current state of bioengineering progress and barriers in bladder augmentation or reconstruction and proposes an innovative method to address the obstacles of bladder augmentation. The ideal tissue-engineered bladder has the characteristics of high biocompatibility, compliance, and specialized urothelium to protect the upper urinary tract and prevent extravasation of urine. Despite that many reports have demonstrated that bioengineered bladder possessed a similar structure to native bladder, few large animal experiments, and clinical applications have been performed successfully. The lack of satisfactory outcomes over the past decades may have become an important factor hindering the development in this field. More studies should be warranted to promote the use of tissue-engineered bladders in clinical practice

Activating mu-opioid receptors in the spinal cord mediates the cardioprotective effect of remote preconditioning of trauma

Background: Remote precoditioning of trauma (RPCT) confers cardioprotective effects against myocardial ischemia/reperfusion injury, which are mediated by spinal opioid receptors. The aim of this study was to identify the roles of opioid receptor subtypes in the cardioprotective effect of RPCT and possible mechanisms. Methods: In this study, 192 Sprague-Dawley rats were allocated to 12 groups. Except for the sham group, rats in all groups were subjected to myocardial ischemia reperfusion. Rats in the ischemia precondition (IPC) group were treated with IPC. In the RPCT groups, an abdominal incision was made 15 min before inducing ischemia. The selective delta-, kappa-, and mu-opioid receptor antagonists were administered to groups of animals receiving RPCT, respectively. Data were collected for myocardial infarct size, intercellular adhesion molecule 1 (ICAM-1), plasma cardiac troponin I (cTnI) concentrations, activation of protein kinase C epsilon (PKCe) in myocardial cell membranes, and adenosine release in the spinal cord. Results: Compared with the control groups, infarct size, plasma concentrations of cTnI, and myocardial ICAM-1 expression were significantly lower, while adenosine release and PKCe activation were enhanced in the IPC and RPCT groups. Compared with the RPCT group, infarct size, plasma cTnI concentration, and myocardial ICAM-1 expression were greater and adenosine release and PKCe activation were reduced in the mu-opioid receptor antagonist plus RPCT group. Conclusions: The spinal mu-opioid receptor mediated the cardiac protective effect of RPCT. The mechanism may be enhanced by adenosine release in the spinal cord and PKCe activation in the myo­cardium, thereby inhibiting inflammation induced by ischemia/reperfusion injury

Heat Transfer Analysis of Passive Residual Heat Removal Heat Exchanger under Tube outside Boiling Condition

The Passive Residual Heat Removal Heat Exchanger (PRHR HX) is an important part of the Passive Residual Heat Removal System (PRHRS). The C-shaped bundle is being used in the PRHR HX. A test facility of C-shaped tube immerged in a water tank was built to research the heat transfer of the PRHR HX. Through the experiments, three regions were found within a particular period of time during the heating process in the tank: natural convection region, transition region, and saturation boiling region. For the tube outside saturation boiling, comparisons of three different correlations in literatures with the experimental data were carried out. Results show that the Rohsenow correlation provides a best-estimate fit with the experimental results. For the tube outside transition region, a formulation is put forward to reduce error based on the Rohsenow subcooled boiling correlation

Upper urinary dilatation and treatment of 26 patients with diabetes insipidus: A single-center retrospective study

ObjectiveTo describe the urinary tract characteristics of diabetes insipidus (DI) patients with upper urinary tract dilatation (UUTD) using the video-urodynamic recordings (VUDS), UUTD and all urinary tract dysfunction (AUTD) systems, and to summarize the experience in the treatment of DI with UUTD.MethodsThis retrospective study analyzed clinical data from 26 patients with DI, including micturition diary, water deprivation tests, imaging data and management. The UUTD and AUTD systems were used to evaluate the urinary tract characteristics. All patients were required to undergo VUDS, neurophysiologic tests to confirm the presence of neurogenic bladder (NB).ResultsVUDS showed that the mean values for bladder capacity and bladder compliance were 575.0 ± 135.1 ml and 51.5 ± 33.6 cmH2O in DI patients, and 42.3% (11/26) had a post-void residual >100 ml. NB was present in 6 (23.1%) of 26 DI patients with UUTD, and enterocystoplasty was recommended for two patients with poor bladder capacity, compliance and renal impairment. For the 24 remaining patients, medication combined with individualized and appropriate bladder management, including intermittent catheterization, indwelling catheter and regular voiding, achieved satisfactory results. High serum creatinine decreased from 248.0 ± 115.8 μmoI/L to 177.4 ± 92.8 μmoI/L in 12 patients from a population with a median of 108.1 μmoI/L (IQR: 79.9-206.5 μmoI/L). Forty-four dilated ureters showed significant improvement in the UUTD grade, and the median grade of 52 UUTD ureters decreased from 3 to 2.ConclusionBladder distension, trabeculation and decreased or absent sensations were common features for DI patients with UUTD. Individualized therapy by medication combined with appropriate bladder management can improve UUTD and renal function in DI patients

Spatial Uncertainty-Aware Semi-Supervised Crowd Counting

Semi-supervised approaches for crowd counting attract attention, as the fully supervised paradigm is expensive and laborious due to its request for a large number of images of dense crowd scenarios and their annotations. This paper proposes a spatial uncertainty-aware semi-supervised approach via regularized surrogate task (binary segmentation) for crowd counting problems. Different from existing semi-supervised learning-based crowd counting methods, to exploit the unlabeled data, our proposed spatial uncertainty-aware teacher-student framework focuses on high confident regions' information while addressing the noisy supervision from the unlabeled data in an end-to-end manner. Specifically, we estimate the spatial uncertainty maps from the teacher model's surrogate task to guide the feature learning of the main task (density regression) and the surrogate task of the student model at the same time. Besides, we introduce a simple yet effective differential transformation layer to enforce the inherent spatial consistency regularization between the main task and the surrogate task in the student model, which helps the surrogate task to yield more reliable predictions and generates high-quality uncertainty maps. Thus, our model can also address the task-level perturbation problems that occur spatial inconsistency between the primary and surrogate tasks in the student model. Experimental results on four challenging crowd counting datasets demonstrate that our method achieves superior performance to the state-of-the-art semi-supervised methods

Survival of Surfactant Protein-A1 and SP-A2 Transgenic Mice After Klebsiella pneumoniae Infection, Exhibits Sex-, Gene-, and Variant Specific Differences; Treatment With Surfactant Protein Improves Survival

Surfactant protein A (SP-A) is involved in lung innate host defense and surfactant-related functions. The human SFTPA1 and SFTPA2 genes encode SP-A1 and SP-2 proteins, and each gene has been identified with numerous genetic variants. SP-A1 and SP-A2 differentially enhance bacterial phagocytosis. Sex differences have been observed in pulmonary disease and in survival of wild type and SP-A knockout (KO) mice. The impact of human SP-A variants on survival after infection is unknown. In this study, we determined whether SP-A variants differentially affect survival of male and female mice infected with Klebsiella pneumoniae. Transgenic (TG) mice, where each carries a different human (h) SP-A1 (6A2, 6A4), SP-A2 (1A0, 1A3) variant or both variants SP-A1/SP-A2 (6A2/1A0, co-ex), and SP-A- KO, were utilized. The hTG and KO mice were infected intratracheally with K. pneumoniae bacteria, and groups of KO mice were treated with SP-A1 or SP-A2 either prior to and/or at the time of infection and survival for both experimental groups was monitored over 14 days. The binding of purified SP-A1 and SP-A2 proteins to phagocytic and non-phagocytic cells and expression of cell surface proteins in alveolar macrophages (AM) from SP-A1 and SP-A2 mice was examined. We observed gene-, variant-, and sex-specific (except for co-ex) differences with females showing better survival: (a) Gene-specific differences: co-ex = SP-A2 > SP-A1 > KO (both sexes); (b) Variant-specific survival co-ex (6A2/1A0) = 1A0 > 1A3 = 6A2 > 6A4 (both sexes); (c) KO mice treated with SPs (SP-A1 or SP-A2) proteins exhibit significantly (p < 0.05) better survival; (d) SP-A1 and SP-A2 differentially bind to phagocytic, but not to non-phagocytic cells, and AM from SP-A1 and SP-A2 hTG mice exhibit differential expression of cell surface proteins. Our results indicate that sex and SP-A genetics differentially affect survival after infection and that exogenous SP-A1/SP-A2 treatment significantly improves survival. We postulate that the differential SP-A1/SP-A2 binding to the phagocytic cells and the differential expression of cell surface proteins that bind SP-A by AM from SP-A1 and SP-A2 mice play a role in this process. These findings provide insight into the importance of sex and innate immunity genetics in survival following infection

The Changes of Intrinsic Excitability of Pyramidal Neurons in Anterior Cingulate Cortex in Neuropathic Pain

To find satisfactory treatment strategies for neuropathic pain syndromes, the cellular mechanisms should be illuminated. Central sensitization is a generator of pain hypersensitivity, and is mainly reflected in neuronal hyperexcitability in pain pathway. Neuronal excitability depends on two components, the synaptic inputs and the intrinsic excitability. Previous studies have focused on the synaptic plasticity in different forms of pain. But little is known about the changes of neuronal intrinsic excitability in neuropathic pain. To address this question, whole-cell patch clamp recordings were performed to study the synaptic transmission and neuronal intrinsic excitability 1 week after spared nerve injury (SNI) or sham operation in male C57BL/6J mice. We found increased spontaneous excitatory postsynaptic currents (sEPSC) frequency in layer II/III pyramidal neurons of anterior cingulate cortex (ACC) from mice with neuropathic pain. Elevated intrinsic excitability of these neurons after nerve injury was also picked up, which was reflected in gain of input-output curve, inter-spike interval (ISI), spike threshold and Refractory period (RP). Besides firing rate related to neuronal intrinsic excitability, spike timing also plays an important role in neural information processing. The precision of spike timing measured by standard deviation of spike timing (SDST) was decreased in neuropathic pain state. The electrophysiological studies revealed the elevated intrinsic excitation in layer II/III pyramidal neurons of ACC in mice with neuropathic pain, which might contribute to central excitation