Bolted and hybrid beam-column joints between I-shaped FRP profiles Chapter Bolted and hybrid beam-column joints between I-shaped FRP profiles

Presented are test results from five full-scale pultruded FRP beam-to-column joints subjected to cyclic load-ing. The parameters include cleat position, connection method and cleat material. The joints’ behaviour is assessed through hysteresis moment rotation loops, accumulated dissipated energy and failure patterns. The hybrid joints with steel cleats showed the best overall cyclic performance with accumulated dissipated ener-gy 75% higher than the bolted joint. The bolted joint with FRP cleats exhibited the lowest dissipated energy, four times lower than the joint with steel cleats. The cyclic performance of web and flange cleated joint was same as flange cleated joint. Three failure patterns were noticed, namely shear-out failure of the beam’s bolted region (bolted joint with steel cleats), adhesive debonding followed by shear-out failure (hybrid joint with steel cleats) and delamination cracking (bolted joint with FRP cleats)

Cyclic Response of Bolted and Hybrid Pultruded FRP Beam-Column Joints between I-Shaped Sections

This paper presents cyclic behaviour of bolted and hybrid–combined bolted and bonded fibre re-inforced polymer (FRP) beam-to-column joints between I-shaped members using steel and FRP cleats. Five full-scale cyclic tests are carried out to study moment-rotation behaviour, cyclic re-sponse, and failure patterns. The test parameters include position of cleat (flange or combined web and flange), fastening method (bolting or hybrid–combining bolting and bonding) and cleat ma-terial (steel or FRP). First two tests had bolted and hybrid joints with steel flange and web double angles. Next two tests had the same joint detailing but with no web cleats. Last test used bolted joint only with FRP web and flange cleats. Three failure modes were observed: shear-out failure of the beam’s bolted zone, adhesive debonding with shear-out failure and delamination cracking. Cyclic performance of the joints was assessed by hysteresis moment-rotation curves and accumulated dissipated energy. Hybrid joints showed the best overall cyclic performance with accumulated dissipated energy about 75% higher than the bolted joints. Bolted joints with FRP cleats exhibited the worst cyclic performance. Flange cleated joints showed similar performance to web and flange cleated joints

NGO online disclosures index in the presence of auxiliary information

This study highlights the need for analysis of online disclosure practices followed by nongovernmental organizations; furthermore, it justifies the crucial role of potential correlates of online disclosure practices followed by non-governmental organizations. We propose a novel index for analyzing the extent of online disclosure of non-governmental organizations (NGO). Using the information stored in an auxiliary variable, we propose a new estimator for gauging the average value of the proposed index. Our approach relies on the use of two factors: imperfect ranked-set sampling procedure to link the auxiliary variable with the study variable, and an NGO disclosure index under simple random sampling that uses information only about the study variable. Relative efficiency of the proposed index is compared with the conventional estimator for the population average under the imperfect ranked-set sampling scheme. Mathematical conditions required for retaining the efficiency of the proposed index, in comparison to the imperfect ranked set sampling estimator, are derived. Numerical scrutiny of the relative efficiency, in response to the input variables, indicates; if the variance of the NGO disclosure index is less than the variance of the estimator under imperfect ranked set sampling, then the proposed index is universally efficient compared to the estimator under imperfect ranked set sampling. If the condition on variances is unmet, even then the proposed estimator remains efficient if majority of the NGO share online data on the auxiliary variable. This work can facilitate nonprofit regulation in the countries where most of the non-governmental organizations maintain their websites

MicroRNA Modulate Alveolar Epithelial Response to Cyclic Stretch

Background MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression implicated in multiple cellular processes. Cyclic stretch of alveoli is characteristic of mechanical ventilation, and is postulated to be partly responsible for the lung injury and inflammation in ventilator-induced lung injury. We propose that miRNAs may regulate some of the stretch response, and therefore hypothesized that miRNAs would be differentially expressed between cyclically stretched and unstretched rat alveolar epithelial cells (RAECs). Results RAECs were isolated and cultured to express type I epithelial characteristics. They were then equibiaxially stretched to 25% change in surface area at 15 cycles/minute for 1 hour or 6 hours, or served as unstretched controls, and miRNAs were extracted. Expression profiling of the miRNAs with at least 1.5-fold change over controls revealed 42 miRNAs were regulated (34 up and 8 down) with stretch. We validated 6 of the miRNAs using real-time PCR. Using a parallel mRNA array under identical conditions and publicly available databases, target genes for these 42 differentially regulated miRNAs were identified. Many of these genes had significant up- or down-regulation under the same stretch conditions. There were 362 down-regulated genes associated with up-regulated miRNAs, and 101 up-regulated genes associated with down-regulated miRNAs. Specific inhibition of two selected miRNAs demonstrated a reduction of the increased epithelial permeability seen with cyclic stretch. Conclusions We conclude that miRNA expression is differentially expressed between cyclically stretched and unstretched alveolar epithelial cells, and may offer opportunities for therapeutic intervention to ameliorate stretch-associated alveolar epithelial cell dysfunction

Age-related Hearing Loss and its Association with Reactive Oxygen Species and Mitochondrial DNA damage

Age-related hearing loss, known as presbyacusis, is characterized by the progressive deterioration of auditory sensitivity associated with the aging process and is the leading cause of adult auditory deficiency in the USA. Presbyacusis is described as a progressive, bilateral, high-frequency hearing loss that is manifested on audiometric assessment by a moderately sloping pure tone audiogram. Approximately 23% of the population between 65 and 75 years of age, and 40% of the population older than 75 years of age are affected by this condition. It was estimated in 1980 that 11% of the population was 76 years or older and this number is expected to almost double by the year 2030. When one considers that the population over 65 years of age is experiencing the most accelerated development of hearing loss, the potential socioeconomic ramifications are staggering. Curiously, the frequency of presbyacusis varies across different societies. This discrepancy has been attributed to many factors including genetics, diet, socioeconomic factors, and environmental variables. The purpose of this article is to review the various molecular mechanisms underlying presbyacusis and to offer insights into potential methods of mitigating the effects of aging on hearing impairment

A study of minimally invasive percutaneous plate osteosynthesis for tibial plateau fractures

Background: Fractures of proximal tibia involve a major weight-bearing joint and are serious injuries, which, if not treated well, result in functional impairment. To preserve normal knee function one must strive to maintain joint congruity, preserve the normal mechanical axis, ensure joint stability and restore a full range of motion. This is a formidable task to accomplish, especially in the face of associated medical conditions of the patients.Methods: In our study, 30 cases were selected. Selection of cases were done on the basis of X-rays. Schatzker type I, II, III, IV, V & VI included in study. Criteria for acceptable reduction 1) <5 mm of articular step; 2) <5 mm of articular depression. Each case is referred to one set of tibial plateau fracture, showing distribution of tibia plateau fractures that we treated with MIPPO. Clinical follow-up examination was performed at 4, 6, 10, 12 weeks and 3, 6 months. Clinico-radiological assessment was done at 3 month and grading was done. Patients were evaluated according to grading minimum 3 months after injury.Results: Our study of 30 tibial plateau fractures confirms that the MIPPO technique is an excellent treatment modality in case of tibial plateau fractures. We observed these fractures mainly in age group of 30-40 years, which were involved in road traffic accident. Tibial plateau fractures seen in elder age group were mainly due to abnormal loading patterns on the leg. We have found oblique views very much informative especially for posterolateral or posteromedial displacement, articular depression which helps to plan the position and direction of screws to be used for fixation. Conclusions: In view of the excellent results obtained with this technique, we advocate MIPPO over conventional open reduction and internal fixation technique for tibial plateau fracture fixation

Phylogeography of Chelonus insularis (Hymenoptera: Braconidae) and Campoletis sonorensis (Hymenoptera: Ichneumonidae), Two Primary Neotropical Parasitoids of the Fall Armyworm (Lepidoptera: Noctuidae)

In a previous study, we observed no spatial genetic structure in Mexican populations of the parasitoids Chelonus insularis Cresson (Hymenoptera: Braconidae) and Campoletis sonorensis Cameron (Hymenoptera: Ichneumonidae) by using microsatellite markers. In the current study, we investigated whether for these important parasitoids of the fall armyworm (Lepidoptera: Noctuidae) there is any genetic structure at a larger scale. Insects of both species were collected across the American continent and their phylogeography was investigated using both nuclear and mitochondrial markers. Our results suggest an ancient north-south migration of C. insularis, whereas no clear pattern could be determined for C. sonorensis. Nonetheless, the resulting topology indicated the existence of a cryptic taxon within this later species: a few Canadian specimens determined as C. sonorensis branch outside a clade composed of the Argentinean Chelonus grioti Blanchard, the Brazilian Chelonus flavicincta Ashmead, and the rest of the C. sonorensis individuals. The individuals revealing the cryptic taxon were collected from Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) on tomato (Lycopersicon spp.) and may represent a biotype that has adapted to the early season phenology of its host. Overall, the loosely defined spatial genetic structure previously shown at a local fine scale also was found at the larger scale, for both species. Dispersal of these insects may be partly driven by wind as suggested by genetic similarities between individuals coming from very distant location

Bovine Follicular Dynamics, Oocyte Recovery,and Development of Oocytes Microinjected with a Green Fluorescent Protein Construct

The present study was carried out to 1) evaluate the viability of in vitro fertilized zygotes after microinjection of DNA, 2) assess the influence of oocyte quality upon the development rate of embryos when injected with DNA, and 3) determine the integration frequency of green fluorescent protein DNA into microinjected embryos. Oocytes were aspirated from ovaries of nine nonlactating Holsteins and were categorized into grades A, B, C, and D. At 16 h after in vitro fertilization, approximately half of the pronuclear stage presumptive zygotes were classified as having 1 pronucleus or 2 pronuclei, and they were microinjected with DNA constructs. A potential predictor of DNA integration frequency at d 10 was assessment of the incidence of green fluorescing embryos. The proportion of cleaved embryos that developed to morulae or blastocysts was not different between groups with 1 pronucleus injected (45%), 1 pronucleus uninjected (64%), or 2 pronuclei injected (49%). However, the development of morulae or blastocysts was higher in the group with 2 pronuclei uninjected (69%). The overall developmental score of green fluorescent protein-positive embryos was higher for grade A oocytes (1.3 &#;&#;0.1) than for grade B (0.8 &#; 0.1), C (0.6 &#;&#;0.1), or D (0.3 &#;&#;0.1) oocytes. The results show that production of transgenic bovine blastocysts can occur from the microinjection of a presumptive zygote having only one visible pronucleus. Initial oocyte quality is an important factor in selection of oocytes suitable for microinjection of DNA and for preimplantation development to produce bovine transgenic embryos

Identification of Hibernating Myocardium: Comparative Accuracy of Myocardial Contrast Echocardiography, Rest-Redistribution Thallium-201 Tomography and Dobutamine Echocardiography

AbstractObjectives. We sought to evaluate the comparative accuracy of myocardial contrast echocardiography (MCE), quantitative rest-redistribution thallium-201 (Tl-201) tomography and low and high dose (up to 40 μg/kg body weight per min) dobutamine echocardiography (DE) in identifying myocardial hibernation.Background. Myocardial contrast echocardiography can assess myocardial perfusion and may therefore be useful in predicting myocardial hibernation. However, its accuracy in comparison to myocardial perfusion scintigraphy and to that of high dose DE remains to be investigated.Methods. Eighteen patients (aged [±SD] 57 ± 10 years) with stable coronary artery disease and ventricular dysfunction underwent the above three modalities before coronary revascularization. Myocardial contrast echocardiography was achieved with intracoronary Albunex. Rest echocardiographic and Tl-201 studies were repeated ≥6 weeks after revascularization.Results. Of 109 revascularized segments with severe dysfunction, 46 (42%) improved. Left ventricular ejection fraction increased from 38 ± 14% to 45 ± 13% at follow-up (p = 0.003). Rest Tl-201 uptake and the ratio of peak contrast intensity of dysfunctional to normal segments with MCE were higher (p < 0.01) in segments that recovered function compared with those that did not. Myocardial contrast echocardiography, thallium scintigraphy and any contractile reserve during DE had a similar sensitivity (89% to 91%) with a lower specificity (43% to 66%) for recovery of function. A biphasic response during DE was the most specific (83%) and the least sensitive (68%) (p < 0.01). The best concordance with MCE was Tl-201 (80%, kappa 0.57). Changes in ejection fraction after revascularization related significantly to the number of viable dysfunctional segments by all modalities (r = 0.54 to 0.65).Conclusions. In myocardial hibernation, methods evaluating rest perfusion (MCE, Tl-201) or any contractile reserve have a similar high sensitivity but a low specificity for predicting recovery of function. A limited contractile reserve (biphasic response) increases the specificity of DE. Importantly, the three techniques identified all patients who had significant improvement in global ventricular function.(J Am Coll Cardiol 1997;29:985–93)© 1997 by the American College of Cardiolog