Growth of YBa2Cu3O7-δ Thin-Films–Nucleation, Heteroepitaxy and Interfaces

A major research effort in high-temperature oxide superconductors is the growth of high-quality thin-films. The physical properties of polycrystalline thin-films are controlled by their microstructure which is influenced by the early stages of film growth and the establishment of epitaxy. In this article, the nucleation and heteroepitactic growth of YBa2Cu3O7-δ thin-films is reviewed. Many of the examples illustrating film growth will be taken from studies using transmission electron microscopy. The importance of the substrate surface in controlling film growth will be discussed, in particular the growth of YBa2Cu3O7-δ films on vicinal MgO surfaces, enabling the formation of highly-oriented microstructures on a substrate where there is a large lattice mismatch. In this case, film growth is described as a form of graphoepitaxy, and models will be presented to show the mechanism for film growth and also how the lattice misfit can be reduced by small rotations of the YBa2Cu3O7-δ lattice

Modified Electron Beam Induced Deposition of Metal Nanostructure Arrays using a Parallel Electron Beam

A modified electron beam induced deposition method using a parallel beam of electrons is developed. The method relies on the build-up of surface potential on an insulating surface exposed to an electron beam. Presence of sharp edges on the insulating surface implies presence of large electric fields that lead to site-specific nucleation of metal vapor on those regions. Feature sizes as small as 20 nm can be deposited without the need to use fine probes and thus the limitation of probe size imposed on the resolution is overcome. The use of pure metal vapor also renders the process inherently clean.Comment: 14 Pages, 3 figures, to appear in Applied Physics Letter

Growth and texture of Spark Plasma Sintered Al2O3 ceramics: a combined analysis of X-rays and Electron Back Scatter Diffraction

Textured alumina ceramics were obtained by Spark Plasma Sintering (SPS) of undoped commercial a-Al2O3 powders. Various parameters (density, grain growth, grain size distribution) of the alumina ceramics, sintered at two typical temperatures 1400{\deg}C and 1700{\deg}C, are investigated. Quantitative textural and structural analysis, carried out using a combination of Electron Back Scattering Diffraction (EBSD) and X-ray diffraction (XRD), are represented in the form of mapping, and pole figures. The mechanical properties of these textured alumina ceramics include high elastic modulus and hardness value with high anisotropic nature, opening the door for a large range of applicationsComment: 16 pages, 6 figures, submitted to J. Appl. Phy

Global citizenship as the completion of cosmopolitanism

A conception of global citizenship should not be viewed as separate from, or synonymous with, the cosmopolitan moral orientation, but as a primary component of it. Global citizenship is fundamentally concerned with individual moral requirements in the global frame. Such requirements, framed here as belonging to the category of individual cosmopolitanism, offer guidelines on right action in the context of global human community. They are complementary to the principles of moral cosmopolitanism – those to be used in assessing the justice of global institutions and practices – that have been emphasised by cosmopolitan political theorists. Considering principles of individual and moral cosmopolitanism together can help to provide greater clarity concerning individual duties in the absence of fully global institutions, as well as clarity on individual obligations of justice in relation to emerging and still-developing trans-state institutions

The detection, survival and persistence of Staphylococcus capitis NRCS-A in neonatal units in England

BACKGROUND: The multi-drug resistant Staphylococcus capitis clone, NRCS-A is increasingly associated with late-onset sepsis in low birthweight newborns in neonatal intensive care units (NICUs) in England and globally. Understanding where this bacterium survives and persists within the NICU environment is key to developing and implementing effective control measures. AIM: To investigate the potential for S. capitis to colonise surfaces within NICUs. METHODS: Surface swabs were collected from four NICUs with and without known NRCS-A colonisations/infections present at the time of sampling. Samples were cultured and S. capitis isolates analysed via whole genome sequencing. Survival of NRCS-A on plastic surfaces was assessed over time and compared to that of non-NRCS-A isolates. The bactericidal activity of commonly used chemical disinfectants against S. capitis was assessed. FINDINGS: Of 173 surfaces sampled, 40 (21.1%) harboured S. capitis with 30 isolates (75%) being NRCS-A. Whilst S. capitis was recovered from surfaces across the NICU, the NRCS-A clone was rarely recovered from outside the immediate neonatal bedspace. Incubators and other bedside equipment were contaminated with NRCS-A regardless of clinical case detection. In the absence of cleaning, S. capitis was able to survive for 3 days with minimal losses in viability (< 0.5 log10 reduction). Sodium troclosene and a QAC-based detergent/disinfectant reduced S. capitis to below detectable levels. CONCLUSION: S. capitis NRCS-A can be readily recovered from the NICU environment, even in units with no recent reported clinical cases of S. capitis infection, highlighting a need for appropriate national guidance on cleaning within the neonatal care environment

Transcriptomic Analysis of Equine Chorioallantois Reveals Immune Networks and Molecular Mechanisms Involved in Nocardioform Placentitis

Nocardioform placentitis (NP) continues to result in episodic outbreaks of abortion and preterm birth in mares and remains a poorly understood disease. The objective of this study was to characterize the transcriptome of the chorioallantois (CA) of mares with NP. The CA were collected from mares with confirmed NP based upon histopathology, microbiological culture and PCR for Amycolatopsis spp. Samples were collected from the margin of the NP lesion (NPL, n = 4) and grossly normal region (NPN, n = 4). Additionally, CA samples were collected from normal postpartum mares (Control; CRL, n = 4). Transcriptome analysis identified 2892 differentially expressed genes (DEGs) in NPL vs. CRL and 2450 DEGs in NPL vs. NPN. Functional genomics analysis elucidated that inflammatory signaling, toll-like receptor signaling, inflammasome activation, chemotaxis, and apoptosis pathways are involved in NP. The increased leukocytic infiltration in NPL was associated with the upregulation of matrix metalloproteinase (MMP1, MMP3, and MMP8) and apoptosis-related genes, such as caspases (CASP3 and CASP7), which could explain placental separation associated with NP. Also, NP was associated with downregulation of several placenta-regulatory genes (ABCG2, GCM1, EPAS1, and NR3C1), angiogenesis-related genes (VEGFA, FLT1, KDR, and ANGPT2), and glucose transporter coding genes (GLUT1, GLUT10, and GLUT12), as well as upregulation of hypoxia-related genes (HIF1A and EGLN3), which could elucidate placental insufficiency accompanying NP. In conclusion, our findings revealed for the first time, the key regulators and mechanisms underlying placental inflammation, separation, and insufficiency during NP, which might lead to the development of efficacious therapies or diagnostic aids by targeting the key molecular pathways

Applying strategies from libertarian paternalism to decision making for prostate specific antigen (PSA) screening

<p>Abstract</p> <p>Background</p> <p>Despite the recent publication of results from two randomized clinical trials, prostate specific antigen (PSA) screening for prostate cancer remains a controversial issue. There is lack of agreement across studies that PSA screening significantly reduces prostate cancer mortality. In spite of these facts, the widespread use of PSA testing in the United States leads to overdetection and overtreatment of clinically indolent prostate cancer, and its associated harms of incontinence and impotence.</p> <p>Discussion</p> <p>Given the inconclusive results from clinical trials and incongruent PSA screening guidelines, the decision to screen for prostate cancer with PSA testing is an uncertain one for patients and health care providers. Screening guidelines from some health organizations recommend an informed decision making (IDM) or shared decision making (SDM) approach for deciding on PSA screening. These approaches aim to empower patients to choose among the available options by making them active participants in the decision making process. By increasing involvement of patients in the clinical decision-making process, IDM/SDM places more of the responsibility for a complex decision on the patient. Research suggests, however, that patients are not well-informed of the harms and benefits associated with prostate cancer screening and are also subject to an assortment of biases, emotion, fears, and irrational thought that interferes with making an informed decision. In response, the IDM/SDM approaches can be augmented with strategies from the philosophy of libertarian paternalism (LP) to improve decision making. LP uses the insights of behavioural economics to help people better make better choices. Some of the main strategies of LP applicable to PSA decision making are a default decision rule, framing of decision aids, and timing of the decision. In this paper, we propose that applying strategies from libertarian paternalism can help with PSA screening decision-making.</p> <p>Summary</p> <p>Our proposal to augment IDM and SDM approaches with libertarian paternalism strategies is intended to guide patients toward a better decision about testing while maintaining personal freedom of choice. While PSA screening remains controversial and evidence conflicting, a libertarian-paternalism influenced approach to decision making can help prevent the overdiagnosis and overtreatment of prostate cancer.</p

Consequences of converting graded to action potentials upon neural information coding and energy efficiency

Information is encoded in neural circuits using both graded and action potentials, converting between them within single neurons and successive processing layers. This conversion is accompanied by information loss and a drop in energy efficiency. We investigate the biophysical causes of this loss of information and efficiency by comparing spiking neuron models, containing stochastic voltage-gated Na+ and K+ channels, with generator potential and graded potential models lacking voltage-gated Na+ channels. We identify three causes of information loss in the generator potential that are the by-product of action potential generation: (1) the voltage-gated Na+ channels necessary for action potential generation increase intrinsic noise and (2) introduce non-linearities, and (3) the finite duration of the action potential creates a ‘footprint’ in the generator potential that obscures incoming signals. These three processes reduce information rates by ~50% in generator potentials, to ~3 times that of spike trains. Both generator potentials and graded potentials consume almost an order of magnitude less energy per second than spike trains. Because of the lower information rates of generator potentials they are substantially less energy efficient than graded potentials. However, both are an order of magnitude more efficient than spike trains due to the higher energy costs and low information content of spikes, emphasizing that there is a two-fold cost of converting analogue to digital; information loss and cost inflation