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Deformation of Wrinkled Graphene
No full textThe deformation of monolayer graphene, produced by chemical vapor deposition (CVD), on a polyester film substrate has been investigated through the use of Raman spectroscopy. It has been found that the microstructure of the CVD graphene consists of a hexagonal array of islands of flat monolayer graphene separated by wrinkled material. During deformation, it was found that the rate of shift of the Raman 2D band wavenumber per unit strain was less than 25% of that of flat flakes of mechanically exfoliated graphene, whereas the rate of band broadening per unit strain was about 75% of that of the exfoliated material. This unusual deformation behavior has been modeled in terms of mechanically isolated graphene islands separated by the graphene wrinkles, with the strain distribution in each graphene island determined using shear lag analysis. The effect of the size and position of the Raman laser beam spot has also been incorporated in the model. The predictions fit well with the behavior observed experimentally for the Raman band shifts and broadening of the wrinkled CVD graphene. The effect of wrinkles upon the efficiency of graphene to reinforce nanocomposites is also discussed
Do Medical Students Assess the Credibility of Online or Downloadable Medical Reference Resources?
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The centennial of “Flora Saporto”: Thoughts on the possibility of a Mizrahi-Feminist Alliance
No full text“Flora Saporto” is a 3,700 word story published in February 1914 under the pseudonym Bat Zvi by the suffragist and doyen of early modern Hebrew literature Nehama Puhachevsky (1869-1934). Amazingly, during the century since its publication, this story has been neither discussed nor analysed by either critical or traditional scholars of Hebrew Literature. Yet the case of ‘Flora Saporto’ is not a casual omission of just another text buried among numerous others. This is because Flora Saporto can be conceptualised as the first feminist-Mizrahi story that was written in the Middle East in modern Hebrew. It appears to have also embodied a unique feminist-Mizrahi alliance during late Ottoman Palestine
Ultrasmall Nanoplatforms as Calcium-Responsive Contrast Agents for Magnetic Resonance Imaging
No full textThe preparation of ultrasmall and rigid platforms (USRPs) that are covalently coupled to macrocycle-based, calcium-responsive/smart contrast agents (SCAs), and the initial in vitro and in vivo validation of the resulting nanosized probes (SCA-USRPs) by means of magnetic resonance imaging (MRI) is reported. The synthetic procedure is robust, allowing preparation of the SCA-USRPs on a multigram scale. The resulting platforms display the desired MRI activity-i.e., longitudinal relaxivity increases almost twice at 7 T magnetic field strength upon saturation with Ca(2+). Cell viability is probed with the MTT assay using HEK-293 cells, which show good tolerance for lower contrast agent concentrations over longer periods of time. On intravenous administration of SCA-USRPs in living mice, MRI studies indicate their rapid accumulation in the renal pelvis and parenchyma. Importantly, the MRI signal increases in both kidney compartments when CaCl2 is also administrated. Laser-induced breakdown spectroscopy experiments confirm accumulation of SCA-USRPs in the renal cortex. To the best of our knowledge, these are the first studies which demonstrate calcium-sensitive MRI signal changes in vivo. Continuing contrast agent and MRI protocol optimizations should lead to wider application of these responsive probes and development of superior functional methods for monitoring calcium-dependent physiological and pathological processes in a dynamic manner
Phospho-dependent Regulation of SAMHD1 Oligomerisation Couples Catalysis and Restriction.
No full textSAMHD1 restricts HIV-1 infection of myeloid-lineage and resting CD4+ T-cells. Most likely this occurs through deoxynucleoside triphosphate triphosphohydrolase activity that reduces cellular dNTP to a level where reverse transcriptase cannot function, although alternative mechanisms have been proposed recently. Here, we present combined structural and virological data demonstrating that in addition to allosteric activation and triphosphohydrolase activity, restriction correlates with the capacity of SAMHD1 to form "long-lived" enzymatically competent tetramers. Tetramer disruption invariably abolishes restriction but has varied effects on in vitro triphosphohydrolase activity. SAMHD1 phosphorylation also ablates restriction and tetramer formation but without affecting triphosphohydrolase steady-state kinetics. However phospho-SAMHD1 is unable to catalyse dNTP turnover under conditions of nucleotide depletion. Based on our findings we propose a model for phosphorylation-dependent regulation of SAMHD1 activity where dephosphorylation switches housekeeping SAMHD1 found in cycling cells to a high-activity stable tetrameric form that depletes and maintains low levels of dNTPs in differentiated cells
Understanding the diffusion of Sustainable Product-Service Systems: Insights from the sociology of consumption and practice theory
No full textMultilingualism in a post-industrial city: policy and practice in Manchester
No full textManchester (England), one of the first industrial cities, is now home to over 150 languages. Ethnic minority and migrant communities take active steps to maintain heritage languages in commerce and through education. The paper introduces a model for a holistic approach to profiling urban multilingualism that relies on triangulating a variety of quantitative data sets, observations, and ethnographic interviews. We examine how responses to language diversity reflect an emerging new civic identity, but at the same time rely on private and voluntary sector initiative: While the city officially brands itself as multicultural to attract foreign investment, language provisions are local, responsive, and de-centralised and often outsourced, and aim primarily at ensuring equal access to public services rather than to safeguard or promote cultural heritage or even to cultivate language skills as a workforce resource that is vital to economic growth. In such a complex and dynamic setting, there is a need for a mechanism to continuously monitor changes in language profiles and language needs
Mechanosensitive components of integrin adhesions: Role of vinculin.
No full textExternal forces play a key role in shaping development and normal physiology. Aberrant responses to forces, or changes in the nature of such forces, are implicated in a variety of diseases. Cells contain several types of adhesions, linking them to their external environment. It is through these adhesions that forces are both sensed (from the outside inwards) and applied (from inside to out). Furthermore, several adhesion-based proteins are sensitive to changes in intracellular forces, utilising them for activation and regulation. Here, we outline how vinculin, a key component of integrin-mediated adhesions linking the actin cytoskeleton to the extracellular matrix (ECM), is regulated by force and acts as force transducing protein. We discuss the role of vinculin in vivo and its place in health and disease; summarise the proposed mechanisms by which vinculin is recruited to and activated at integrin-ECM adhesions; and discuss recent findings that place vinculin as the major force sensing and transmitting component of cell-matrix adhesion complexes. Finally, we discuss the role of vinculin in regulating the cellular responses to both the physical properties of the external environment and to externally applied physical stimuli
Community mental health teams for older people: variations in case mix and service receipt (1)
No full textOBJECTIVES:The study sought to identify the characteristics of community-dwelling older people supported by community mental health teams (CMHTs) in England and, in particular, to determine whether there is a common threshold for CMHT entry and/or a core client group.METHODS:Data were collected about a random sample of 15 CMHTs' caseloads, including information about their sociodemographic characteristics, physical health, dependence, mental health, risks and service receipt. The sample was divided into 16 subgroups of people with similar needs for care (case types), and differences between teams were explored.RESULTS:Information was obtained for 1396 patients. Just under half had a functional mental health problem, slightly over a third an organic disorder, seven per cent both, and nine per cent no diagnosis. Considerable variation was found in teams' caseloads, and there was no evidence of a common caseload threshold. Two of the commonest case types represented people with functional diagnoses who were independent in activities of daily living (ADL) and had no/low levels of challenging behaviour. Another representing people with organic/mixed diagnoses, ADL dependence, challenging behaviour and at least one medium risk was also fairly common. The two case types that represented patients with the most complex needs accounted for more than a quarter of some teams' caseloads but less than a tenth of others.CONCLUSIONS:It is wrong to assume that CMHTs all have similar caseloads. Commissioners must ensure that the network of services provided can meet the needs of all eligible patients, whilst more research is required on who such teams should target