218 research outputs found
Experimental Study on Condition Monitoring of Low Speed Bearings : Time Domain Analysis
In condition monitoring of low speed rolling element bearings (REBs), traditional techniques involving vibration acceleration may not be able to detect a growing fault due to the low impact energy generated by the relative motion of the components. This study presents an experimental evaluation for incipient fault detection of low speed REBs by using an acoustic emission (AE) sensor and an accelerometer. A low speed fault simulation test rig was developed to simulate common machine faults with shaft speeds as low as 10rpm under loading conditions. Tests were conducted on the rig with various seeded defect bearings. This study reveals the best frequency bandwidth and suitable parameters for condition monitoring using AE signal for early detection of low speed bearing defects by means of statistical parameters in time domain
Combined Effect of Latex and Crumb Rubber on Mechanical Properties of Concrete for Railway Application
Crumb rubber incorporation is widely deemed to deteriorate the compressive strength of concrete. One of the dominant reasons for this strength reduction is known as the inferior bonding or weak interfacial transition zones (ITZ) between the crumb rubber and hardened cement paste. While Styrene-butadiene (SBR) latex is being used as a bonding agent in concrete manufacturing, the SBR latex usage holds the potential to compensate for the strength reduction from crumb rubber incorporation. This study focuses on evaluating the sole and combined effect of crumb rubber and SBR latex on the compressive strength, one optimum combination of latex modified rubberised mix (LMCRC) that had achieved 55.5 MPa of 28 days characteristic strength was chosen to compare its impact resistance and stress-strain response to a plain concrete (PC) with similar characteristic strength. Experimental results showed both crumb rubber and SBR latex incorporation induced a compressive strength reduction in the concrete. The optimum latex modified rubberised mix with w/c of 0.32, crumb rubber replacement of 20kg/m3, and 3% latex additives had outperformed the control mix with w/c ratio of 0.38 by 66.7% and 293% in the 400mm span impact test and 200mm span impact test, respectively. Besides, the latex modified rubberised mix showed higher Poisson’s ratio, and higher compressive strain which indicates more ductile behaviour as compared to the plain concrete
Combined Effect of Latex and Crumb Rubber on Mechanical Properties of Concrete for Railway Application
Crumb rubber incorporation is widely deemed to deteriorate the compressive strength of concrete. One of the dominant reasons for this strength reduction is known as the inferior bonding or weak interfacial transition zones (ITZ) between the crumb rubber and hardened cement paste. While Styrene-butadiene (SBR) latex is being used as a bonding agent in concrete manufacturing, the SBR latex usage holds the potential to compensate for the strength reduction from crumb rubber incorporation. This study focuses on evaluating the sole and combined effect of crumb rubber and SBR latex on the compressive strength, one optimum combination of latex modified rubberised mix (LMCRC) that had achieved 55.5 MPa of 28 days characteristic strength was chosen to compare its impact resistance and stress-strain response to a plain concrete (PC) with similar characteristic strength. Experimental results showed both crumb rubber and SBR latex incorporation induced a compressive strength reduction in the concrete. The optimum latex modified rubberised mix with w/c of 0.32, crumb rubber replacement of 20kg/m3, and 3% latex additives had outperformed the control mix with w/c ratio of 0.38 by 66.7% and 293% in the 400mm span impact test and 200mm span impact test, respectively. Besides, the latex modified rubberised mix showed higher Poisson’s ratio, and higher compressive strain which indicates more ductile behaviour as compared to the plain concrete
Patient-Provider Discussions about Lung Cancer Screening Pre- and Post-Guidelines: Health Information National Trends Survey (HINTS)
Objective
In 2013, the USPSTF issued a Grade B recommendation that long-term current and former smokers receive lung cancer screening. Shared decision-making is important for individuals considering screening, and patient-provider discussions an essential component of the process. We examined prevalence and predictors of lung cancer screening discussions pre- and post-USPSTF guidelines.
Methods
Data were obtained from two cycles of the Health Information National Trends Survey (2012; 2014). The analyzed sample comprised screening-eligible current and former smokers with no personal history of lung cancer (n = 746 in 2012; n = 795 in 2014). Descriptive and multiple logistic regression analyses were conducted; patient-reported discussion about lung cancer screening with provider was the outcome of interest.
Results
Contrary to expectations, patient-provider discussions about lung cancer screening were more prevalent pre-guideline, but overall patient-provider discussions were low in both years (17% in 2012; 10% in 2014). Current smokers were more likely to have had a discussion than former smokers. Significant predictors of patient-provider discussions included family history of cancer and having healthcare coverage.
Conclusions
The prevalence of patient-provider discussions about lung cancer screening is suboptimal.
Practice implications
There is a critical need for patient and provider education about shared decision-making and its importance in cancer screening decisions
The RNA-binding protein hnRNPLL induces a T cell alternative splicing program delineated by differential intron retention in polyadenylated RNA
BACKGROUND Retention of a subset of introns in spliced polyadenylated mRNA is emerging as a frequent, unexplained finding from RNA deep sequencing in mammalian cells. RESULTS Here we analyze intron retention in T lymphocytes by deep sequencing polyadenylated RNA. We show a developmentally regulated RNA-binding protein, hnRNPLL, induces retention of specific introns by sequencing RNA from T cells with an inactivating Hnrpll mutation and from B lymphocytes that physiologically downregulate Hnrpll during their differentiation. In Ptprc mRNA encoding the tyrosine phosphatase CD45, hnRNPLL induces selective retention of introns flanking exons 4 to 6; these correspond to the cassette exons containing hnRNPLL binding sites that are skipped in cells with normal, but not mutant or low, hnRNPLL. We identify similar patterns of hnRNPLL-induced differential intron retention flanking alternative exons in 14 other genes, representing novel elements of the hnRNPLL-induced splicing program in T cells. Retroviral expression of a normally spliced cDNA for one of these targets, Senp2, partially corrects the survival defect of Hnrpll-mutant T cells. We find that integrating a number of computational methods to detect genes with differentially retained introns provides a strategy to enrich for alternatively spliced exons in mammalian RNA-seq data, when complemented by RNA-seq analysis of purified cells with experimentally perturbed RNA-binding proteins. CONCLUSIONS Our findings demonstrate that intron retention in mRNA is induced by specific RNA-binding proteins and suggest a biological significance for this process in marking exons that are poised for alternative splicing.This work has been supported by grants from the National Health and Medical Research Council (Australia), the Wellcome Trust, the National Institutes of Health (USA) and the Biomedical Research Council (BMRC) of the Agency for Science, Technology and Research (A*STAR), Singapore
SIP-based proactive and adaptive mobility management framework for heterogeneous networks
Abstract In this paper, we present and evaluate the performance of a mobility management system called the Proactive and Adaptive Handover (PAHO) system. PAHO is an application-level approach that uses SIP to manage client-initiated connection handoff across heterogeneous networks based on the IEEE 802.21 framework with designated user/configuration policy. Unlike conventional systems which make sub-optimal decision when managing connection handoff due to limited awareness of the relevant context for the application/service being delivered, PAHO defines proper interface to interact with the application as to determine when and to where the handoff and/or codec switching should take place in the event of network performance degradation. The results showed that using the PAHO approach on an audio/video conferencing session helps reducing the overall handover delay from 10.766 s (on non-PAHO system) down to at least 288 ms, and slowing down the degradation of MOS value throughout the entire experiment in the event of signal degradation as well as network congestion. It is also shown that load balancing among the access points (AP) could be achieved with an improved Information Server (IS). r 2007 Elsevier Ltd. All rights reserved
Home interventions and light therapy for treatment of vitiligo (HI-Light Vitiligo Trial): study protocol for a randomized controlled trial
Vitiligo is a condition resulting in white patches on the skin. People with vitiligo can suffer from low self-esteem, psychological disturbance and diminished quality of life. Vitiligo is often poorly managed, partly due to lack of high quality evidence to inform clinical care. We describe here a large, independent, randomised controlled trial (RCT) assessing the comparative effectiveness of potent topical corticosteroid, home-based hand-held narrowband ultraviolet B-light (NB-UVB) or combination of the two, for the management of vitiligo.
Methods and Analysis
The HI-Light Vitiligo Trial is a multi-centre, three-arm, parallel group, pragmatic, placebo-controlled RCT. 516 adults and children with actively spreading, but limited, vitiligo are randomised (1:1:1) to one of three groups: mometasone furoate 0.1% ointment plus dummy NB-UVB light, vehicle ointment plus NB-UVB light, or mometasone furoate 0.1% ointment plus NB-UVB light. Treatment of up to three patches of vitiligo is continued for up to 9 months with clinic visits at baseline, 3, 6 and 9 months and four post treatment questionnaires.
The HI-Light Vitiligo Trial assesses outcomes included in the vitiligo core outcome set and places emphasis on participants’ views of treatment success. The primary outcome is proportion of participants achieving treatment success (patient-rated Vitiligo Noticeability Scale) for a target patch of vitiligo at 9 months with further independent blinded assessment using digital images of the target lesion before and after treatment. Secondary outcomes include time to onset of treatment response, treatment success by body region, percentage repigmentation, quality of life, time-burden of treatment, maintenance of response, safety, and within-trial cost effectiveness.
Ethics and Dissemination
Approvals were granted by East Midlands–Derby Research Ethics Committee (14/EM/1173) and the MHRA (EudraCT 2014-003473-42). The trial was registered 8th January 2015 ISRCTN (17160087). Results will be published in full as open access in the NIHR Journal library and elsewhere
Fundamentos e aplicações da metodologia de ensaios não destrutivos com células bacterianas
Os Ensaios NĂŁo Destrutivos (END) sĂŁo determinantes para a fiabilidade de materiais cuja integridade Ă© de extrema importância. A tĂ©cnica de Ensaios NĂŁo Destrutivos com cĂ©lulas bacterianas (CB) tem demonstrado viabilidade para deteção de defeitos superficiais, com espessuras e profundidades inferiores a 5 ÎĽm em vários materiais de engenharia. O conhecimento adquirido sobre esta tĂ©cnica já Ă© significativo mas alguns aspetos necessitam de mais desenvolvimentos, como a interação bactĂ©ria-defeito e a viabilidade da tĂ©cnica para condições de superfĂcie diferentes das já ensaiadas.
O objetivo deste trabalho Ă© alargar a tĂ©cnica a uma maior gama de materiais de engenharia com condições de superfĂcie diferentes, assim como, desenvolver o conhecimento sobre a interação bactĂ©ria-defeito.
A bactĂ©ria Rhodococcus erythropolis foi usada na inspeção de vários materiais como AlumĂnio Liga 1100, Estanho, Ouro, Prata, INCONEL 9095, Aço revestido com Nickel, Cobre revestido com Ouro, AlumĂnio revestido com Cobre, PolĂmero com nano tubos de carbono, entre outros, e com condições de superfĂcie diferentes como superfĂcies anodizadas e revestidas. Foram tambĂ©m caracterizados os campos magnĂ©ticos de dois equipamentos desenvolvidos para esta tĂ©cnica de Ensaios NĂŁo Destrutivos.
Os resultados experimentais mostraram que a utilização de campos magnéticos contribui positivamente para a deteção de defeitos e que provetes com revestimentos superficiais diferentes revelam resultados diferentes apesar de terem o mesmo material base
Glutamate Induces Mitochondrial Dynamic Imbalance and Autophagy Activation: Preventive Effects of Selenium
Glutamate-induced cytotoxicity is partially mediated by enhanced oxidative stress. The objectives of the present study are to determine the effects of glutamate on mitochondrial membrane potential, oxygen consumption, mitochondrial dynamics and autophagy regulating factors and to explore the protective effects of selenium against glutamate cytotoxicity in murine neuronal HT22 cells. Our results demonstrated that glutamate resulted in cell death in a dose-dependent manner and supplementation of 100 nM sodium selenite prevented the detrimental effects of glutamate on cell survival. The glutamate induced cytotoxicity was associated with mitochondrial hyperpolarization, increased ROS production and enhanced oxygen consumption. Selenium reversed these alterations. Furthermore, glutamate increased the levels of mitochondrial fission protein markers pDrp1 and Fis1 and caused increase in mitochondrial fragmentation. Selenium corrected the glutamate-caused mitochondrial dynamic imbalance and reduced the number of cells with fragmented mitochondria. Finally, glutamate activated autophagy markers Beclin 1 and LC3-II, while selenium prevented the activation. These results suggest that glutamate targets the mitochondria and selenium supplementation within physiological concentration is capable of preventing the detrimental effects of glutamate on the mitochondria. Therefore, adequate selenium supplementation may be an efficient strategy to prevent the detrimental glutamate toxicity and further studies are warranted to define the therapeutic potentials of selenium in animal disease models and in human
In-Datacenter Performance Analysis of a Tensor Processing Unit
Many architects believe that major improvements in cost-energy-performance
must now come from domain-specific hardware. This paper evaluates a custom
ASIC---called a Tensor Processing Unit (TPU)---deployed in datacenters since
2015 that accelerates the inference phase of neural networks (NN). The heart of
the TPU is a 65,536 8-bit MAC matrix multiply unit that offers a peak
throughput of 92 TeraOps/second (TOPS) and a large (28 MiB) software-managed
on-chip memory. The TPU's deterministic execution model is a better match to
the 99th-percentile response-time requirement of our NN applications than are
the time-varying optimizations of CPUs and GPUs (caches, out-of-order
execution, multithreading, multiprocessing, prefetching, ...) that help average
throughput more than guaranteed latency. The lack of such features helps
explain why, despite having myriad MACs and a big memory, the TPU is relatively
small and low power. We compare the TPU to a server-class Intel Haswell CPU and
an Nvidia K80 GPU, which are contemporaries deployed in the same datacenters.
Our workload, written in the high-level TensorFlow framework, uses production
NN applications (MLPs, CNNs, and LSTMs) that represent 95% of our datacenters'
NN inference demand. Despite low utilization for some applications, the TPU is
on average about 15X - 30X faster than its contemporary GPU or CPU, with
TOPS/Watt about 30X - 80X higher. Moreover, using the GPU's GDDR5 memory in the
TPU would triple achieved TOPS and raise TOPS/Watt to nearly 70X the GPU and
200X the CPU.Comment: 17 pages, 11 figures, 8 tables. To appear at the 44th International
Symposium on Computer Architecture (ISCA), Toronto, Canada, June 24-28, 201
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