67 research outputs found

    Effect of Nano-Silica on The Thermo-Physical Properties of the Thermal Eutectic (Na0.6K0.4)NO3 System

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    Here, we investigate the effect of adding nano-silica particles on the thermo-physical properties of the (Na0.6K0.4)NO3 based thermal energy storage systems. Five different systems tagged as M00, M01, M02, M03 and M04, with different nano-silica percentage of 0, 1, 2, 3, and 4 wt%, respectively, were prepared. Various experimental techniques were employed to study the thermo-physical properties of the systems during (solid-solid) phase P1, (solid-liquid) phase P2 and (liquid-solid) phase P3, and to clarify the effect of nano-silica on the thermal energy storage efficiency during both charging and discharging processes. According to the Differential Scanning Calorimeter (DSC) thermal analysis, it was found that the system M02 whose nano-silica addition rate of 2 wt%, has the most favorable thermal characteristics (i.e., highest specific heat and lowest enthalpy change). Moreover, the addition of 2 wt% represents the optimum distribution of nano-silica inside the principal base system M00. This leads to an improvement in the porosity of the system due to the degree of homogeneity caused by the thermophoresis effect distribution, the high surface area of the nano-silica with the activity of the M00 matrix alongside the degree of the alkalinity of nano-silica. Besides, the electric conductivity measurements showed that the 2wt% percentage is the optimum one for thermal energy storage systems

    Cryo-electron tomography of cells: connecting structure and function

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    Cryo-electron tomography (cryo-ET) allows the visualization of cellular structures under close-to-life conditions and at molecular resolution. While it is inherently a static approach, yielding structural information about supramolecular organization at a certain time point, it can nevertheless provide insights into function of the structures imaged, in particular, when supplemented by other approaches. Here, we review the use of experimental methods that supplement cryo-ET imaging of whole cells. These include genetic and pharmacological manipulations, as well as correlative light microscopy and cryo-ET. While these methods have mostly been used to detect and identify structures visualized in cryo-ET or to assist the search for a feature of interest, we expect that in the future they will play a more important role in the functional interpretation of cryo-tomograms

    Analysis of Adhesion Molecules and Basement Membrane Contributions to Synaptic Adhesion at the Drosophila Embryonic NMJ

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    Synapse formation and maintenance crucially underlie brain function in health and disease. Both processes are believed to depend on cell adhesion molecules (CAMs). Many different classes of CAMs localise to synapses, including cadherins, protocadherins, neuroligins, neurexins, integrins, and immunoglobulin adhesion proteins, and further contributions come from the extracellular matrix and its receptors. Most of these factors have been scrutinised by loss-of-function analyses in animal models. However, which adhesion factors establish the essential physical links across synaptic clefts and allow the assembly of synaptic machineries at the contact site in vivo is still unclear. To investigate these key questions, we have used the neuromuscular junction (NMJ) of Drosophila embryos as a genetically amenable model synapse. Our ultrastructural analyses of NMJs lacking different classes of CAMs revealed that loss of all neurexins, all classical cadherins or all glutamate receptors, as well as combinations between these or with a Laminin deficiency, failed to reveal structural phenotypes. These results are compatible with a view that these CAMs might have no structural role at this model synapse. However, we consider it far more likely that they operate in a redundant or well buffered context. We propose a model based on a multi-adaptor principle to explain this phenomenon. Furthermore, we report a new CAM-independent adhesion mechanism that involves the basement membranes (BM) covering neuromuscular terminals. Thus, motorneuronal terminals show strong partial detachment of the junction when BM-to-cell surface attachment is impaired by removing Laminin A, or when BMs lose their structural integrity upon loss of type IV collagens. We conclude that BMs are essential to tie embryonic motorneuronal terminals to the muscle surface, lending CAM-independent structural support to their adhesion. Therefore, future developmental studies of these synaptic junctions in Drosophila need to consider the important contribution made by BM-dependent mechanisms, in addition to CAM-dependent adhesion

    Rapid and Long-Lasting Increase in Sites for Synapse Assembly during Late-Phase Potentiation in Rat Hippocampal Neurons

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    Long-term potentiation in hippocampal neurons has stages that correspond to the stages of learning and memory. Early-phase (10–30 min) potentiation is accompanied by rapid increases in clusters or puncta of presynaptic and postsynaptic proteins, which depend on actin polymerization but not on protein synthesis. We have now examined changes in pre- and postsynaptic puncta and structures during glutamate-induced late-phase (3 hr) potentiation in cultured hippocampal neurons. We find that (1) the potentiation is accompanied by long-lasting maintenance of the increases in puncta, which depends on protein synthesis, (2) most of the puncta and synaptic structures are very dynamic, continually assembling and disassembling at sites that are more stable than the puncta or structures themselves, (3) the increase in presynaptic puncta appears to be due to both rapid and more gradual increases in the number of sites where the puncta may form, and also to the stabilization of existing puncta, (4) under control conditions, puncta of postsynaptic proteins behave similarly to puncta of presynaptic proteins and share sites with them, and (5) the increase in presynaptic puncta is accompanied by a similar increase in presumably presynaptic structures, which may form at distinct as well as shared sites. The new sites could contribute to the transition between the early and late phase mechanisms of plasticity by serving as seeds for the formation and maintenance of new synapses, thus acting as local “tags” for protein synthesis-dependent synaptic growth during late-phase plasticity

    Neurobiology of rodent self-grooming and its value for translational neuroscience

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    Self-grooming is a complex innate behaviour with an evolutionarily conserved sequencing pattern and is one of the most frequently performed behavioural activities in rodents. In this Review, we discuss the neurobiology of rodent self-grooming, and we highlight studies of rodent models of neuropsychiatric disorders-including models of autism spectrum disorder and obsessive compulsive disorder-that have assessed self-grooming phenotypes. We suggest that rodent self-grooming may be a useful measure of repetitive behaviour in such models, and therefore of value to translational psychiatry. Assessment of rodent self-grooming may also be useful for understanding the neural circuits that are involved in complex sequential patterns of action.National Institutes of Health (U.S.) (Grant NS025529)National Institutes of Health (U.S.) (Grant HD028341)National Institutes of Health (U.S.) (Grant MH060379

    New developments in coordinate measuring machines for manufacturing industries

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    There have been substantial improvements in measurement systems in order to meet fluctuating market demands. This rapid change and development in measurement technology has primarily been governed by demands of accuracy and precision from aerospace, automotive and other manufacturing industries. Coordinate measuring machines (CMMs) available with different technologies and configurations has efficiently been fulfilling customer demands for more than a decade. Though, current CMMs can meet needs of rapid and increased demands of customers to a greater extent but still there is lot of scope for improvement and development in CMMs. The globalization of manufacturing has resulted in development of variety of complex products and miniaturization of mechanical components. The technology of micro/nano-scale 3D measurement is still a bottleneck for industries. Therefore, precise and accurate system which is flexible enough to deal with complexities of parts and micro & nano range products has to be investigated. In this paper, comprehensive review concerning CMMs with capabilities to measure micro/nano features has been presented. This work has also discussed different methods to estimate measurement uncertainty, as well as performance evaluation of CMMs. Moreover, novel concepts such as intelligent CMM, multi-sensor CMM, virtual CMM have been presented

    PUB-0185 Outcome of children with acute lymphoblastic leukemia (ALL) treated on a risk-stratified protocol (PALL08) based on local experience

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    Purpose/Objective: To evaluate outcome of a protocol with risk-stratification based on results of our previous protocols and treatment strategy based on internationally published reports.Materials and Methods: Prospectively collected data on 180 children with ALL treated atour institution on our PALL08 protocol from 2008 and 2012 were analyzed.Results: Median age was 4.6 years (1.1-13.3, 5.5[1]0.24) and 58.3% were male. 160patients with B-ALL were categorized as low risk (LR) if within good-risk ranges for age and WBC count and if good-risk cytogenetics (hyperdiploidy or RUNX1-ETV6) were positive. Children with CNS3 status or with\u3e5% blasts on Day 14 BM evaluation were considered very high risk (VHR). All others, including children with CNS2, were considered high risk (HR). Twenty patients with T-ALL were stratified according to WBC count and CNS positivity into LR (4) and HR (16). Forty-six (25.6%), 103 (57.2%) and 10 (5.6%) children with B-ALL were treated on LR, HR and VHR protocols. Two patients (1.1%) died during induction. 172 patients (95.6%) achieved complete remission at end of induction. Ten (5.8%) patients relapsed at a median of 12.1months (3.5-37, 15.6[1]3.8) from remission. With a median follow up period of 2.3[1]0.124 years the overall survival (OS) was 86.2%and event free survival (EFS) was 83.8% compared to 82.5% and 69.9% on our previous protocol (OS p=0.1 and EFS p=0.02). There was no difference in survival between T- and B-ALL (OS=85.5% v. 93.8% and EFS=84.5% v. 78.9%; p=NS). CNS3 status was associated with poor outcome (EFS=40%) while trisomy 4/10 (EFS=97.4%) andRUNX1-ETV6(EFS=96.3%) conferred good prognosis. Infectious toxicity continues to be high.Conclusions: Although relapse rate on this protocol has decreased from our previous results (21.7%) longer term follow-up to look at relapse and toxicity outcomes is needed. Risk-stratified approach to ALL therapy based on local results is essential to improve outcomes

    State of the Art of Ex-Situ Aluminium Matrix Composite Fabrication through Friction Stir Processing

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    Aluminium metal matrix composites (AMMCs) are the fastest developing materials for structural applications. Friction Stir Processing (FSP) has evolved as a promising surface composite fabrication technique mainly because it is an eco-friendly and solid-state process. A spurt in the interest of research community and a resulting huge research output makes it difficult to find relevant information to further the research with objectivity. To facilitate this, the present article addresses the current state of the art and development in surface metal matrix fabrication through FSP with a specific focus on ex-situ routes. The available literature has been carefully read and categorized to present effects of particle size, morphology and elemental composition. The effect of various reinforcements on development of different functional characteristics is also discussed. Effect of main FSP parameters on various responses is presented with objectivity. Based on the studied literature concluding summary is presented in a manner in which the literature becomes useful to the researchers working on this important technology
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