Graphene-based hybrid materials: synthetic approaches and properties

Carbon has a unique chemistry reflected in its wide presence in the inorganic and organic world - benzene, diamond, graphite, fullerene, carbon nanotubes and now graphene - carbon seems to be at the centre of action in the playground of scientific research. In this review, synthesis and unique properties of graphene and graphene-based composites have been discussed with particular emphasis on the environmentally benign (green) synthetic methods and their wide applications, especially in energy conversion, energy storage, electronics, biomedical and biosensing applications

PKCθ Regulates T Cell Motility via Ezrin-Radixin-Moesin Localization to the Uropod

Cell motility is a fundamental process crucial for function in many cell types, including T cells. T cell motility is critical for T cell-mediated immune responses, including initiation, activation, and effector function. While many extracellular receptors and cytoskeletal regulators have been shown to control T cell migration, relatively few signaling mediators have been identified that can modulate T cell motility. In this study, we find a previously unknown role for PKCθ in regulating T cell migration to lymph nodes. PKCθ localizes to the migrating T cell uropod and regulates localization of the MTOC, CD43 and ERM proteins to the uropod. Furthermore, PKCθ-deficient T cells are less responsive to chemokine induced migration and are defective in migration to lymph nodes. Our results reveal a novel role for PKCθ in regulating T cell migration and demonstrate that PKCθ signals downstream of CCR7 to regulate protein localization and uropod formation.</p

Pregled AC-DC i DC-DC pretvarača za primjene u LED rasvjeti

High-Brightness Light Emitting Diodes (HB-LEDs) are considered the future trend in lighting not only due to their high efficiency and high reliability, but also due to their other outstanding characteristics: chromatic variety, shock and vibration resistance, etc. Nevertheless, they need the development of new power supplies especially designed for boosting and taking advantage of their aforementioned characteristics. Besides, their behaviour is completely different from the rest of lighting devices and, consequently, it should be also taken into account in the design of the converters used to drive them. As a result, many well-known topologies have been optimized or redesigned in order to be used in LED–lighting applications and many new topologies have come up in the recent years with the same purpose. In this paper, the main HB-LED characteristics will be explained, highlighting how they influence the design of their power supplies. After, the main topologies will be presented from the simplest to the most complex ones, analysing their advantages and disadvantages.Svjetleće diode s visokom razinom svjetline (HB-LED) smatraju se budućim trendom u rasvjeti zahvaljujući ne samo visokom stupnju efikasnosti i pouzdanosti, nego i njihovim izvanrednim svojstvima: raznolikost boja, otpornost na udarce i vibracije i sl. Ipak, s ciljem potpunog iskorištenja prethodno spomenutih svojstava, potrebno je razviti nove, posebno osmišljene izvore napajanja. Osim toga, ponašanje im se posve razlikuje od ostalih tipova rasvjete što je potrebno uzeti u obzir pri projektiranju pretvarača za njihovo napajanje. Kao posljedica toga, mnoge su poznate topologije pretvarača optimirane ili preoblikovane posebno za primjenu u LED rasvjeti, a zadnjih nekoliko godina mnoge nove su se tek pojavile. U ovom članku objašnjena su osnovna HB-LED svojstva naglašavajući njihov utjecaj na razvoj izvora napajanja. Uz to, prikazane su osnovne topologije, od najjednostavnijih do najsloženijih, ujedno analizirajući prednosti i nedostatke pojedinih

Differences in access to Emergency Paediatric Intensive Care and care during Transport (DEPICT): study protocol for a mixed methods study

Introduction Following centralisation of UK paediatric intensive care, specialist retrieval teams were established who travel to general hospitals to stabilise and transport sick children to regional paediatric intensive care units (PICUs). There is national variation among these PICU retrieval teams (PICRTs) in terms of how quickly they reach the patient’s bedside and in the care provided during transport. The impact of these variations on clinical outcomes and the experience of stakeholders (patients, families and healthcare staff) is however unknown. The primary objective of this study is to address this evidence gap. Methods and analysis This mixed-methods project involves the following: (1) retrospective analysis of linked data from routine clinical audits (2014–2016) to assess the impact of service variations on 30-day mortality and other secondary clinical outcomes; (2) a prospective questionnaire study conducted at 24 PICUs and 9 associated PICRTs in England and Wales over a 12-month period in 2018 to collect experience data from parents of transported children as well as qualitative analysis of in-depth interviews with a purposive sample of patients, parents and staff to assess the impact of service variations on patient/family experience; (3) health economic evaluation analysing transport service costs (and other associated costs) against lives saved and longer term measurements of quality of life at 12 months in transported children and (4) mathematical modelling evaluating the costs and potential impact of different service configurations. A final work stream involves a series of stakeholder workshops to synthesise study findings and generate recommendations. Ethics and dissemination The study has been reviewed and approved by the Health Research Authority, ref: 2 18 569. Study results will be actively disseminated through peer-reviewed journals, conference presentations, social media, print and broadcast media, the internet and stakeholder workshops

Studies of mechanical, themal and fabrication characteristics of multifunctional structural metals.

Structural materials, in addition to bearing load, are being sought to perform other functions such as enforcing mechanical compatibility between materials, heat exchange and crash energy absorption. Such needs have led to the development of multifunctional materials, notable among these, and those studied in this research, being compositionally and functionally graded materials (FGM's) and cellular metals. FGM's can be used to reduce thermal expansion mismatch between two materials such as a functional coating and a load-bearing substrate. In such cases, the deformation and creep behavior of the composite interlayers between the two materials becomes of interest. To study this aspect, composites of typical FGM materials, a nickel base superalloy and zirconia, were fabricated by powder metallurgy. It was found that zirconia reacted with Y' (Ni3Al) to form alumina and introduced elemental zirconium and oxygen into the superalloy matrix. These changes resulted in greater strengthening than that expected from composite theory at lower creep rates. At higher creep rates, though, weakening of the composites relative to the original alloy was observed. For the part of research directed toward cellular structures, techniques were developed to fabricate hexagonal honeycomb structures and a bonded woven wire mesh structure. High temperature deformation properties of the honeycomb structures in the transverse (in-plane) direction were investigated. Differences in elastic and anelastic behavior and creep strengths from those observed in solid materials are attributed mainly to the open nature of the structures. Creep in the honeycombs is characterized by cycles of primary, secondary and tertiary stages caused by shear instability in layers of cells. Room temperature tests on the woven wire bonded structure showed sharp yielding in tension but gradual yielding and higher strength in compression. Thermal expansion behavior of some cellular structures was studied since it is of interest in material compatibility. It was learned that in addition to the actual geometry of design, defects such as lack of bonding between metal constituents and residual stresses can alter thermal expansive behavior of these materials. These factors in turn can be used as a means to control thermal expansion.Ph.D.Applied SciencesMaterials scienceUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/123253/2/3068939.pd

Evaluation of power losses in a boost PFC unit by temperature measurements

10.1109/TIA.2007.904431IEEE Transactions on Industry Applications4351320-1328ITIA