Preparation and characterization of adherent autocatalytically deposited nickel coating on carbon fiber

In the present study carbon fibers were successfully coated with nanocrystalline nickel using an acidic bath by electroless plating method. Coating thickness obtained was about 1.5 microns beyond that there was coating delamination. Coated fibers were characterized for various properties such as morphology, composition, structure, phase transformation temperature, resistivity and tensile strength. Field emission scanning electron microscope (FESEM) studies revealed that the coating showed nodular morphology. Energy dispersive analysis of X-ray (EDAX) showed that the coating containing about 10.5 wt.% P with balance Ni. Structural studies carried out on these coated fibers exhibited two major diffraction peaks and were assigned as C (002) and Ni (111). Differential scanning calorimetry (DSC) studies on these coated fibers exhibited a single exothermic peak at 3510C. Activation energy obtained for the crystallization process of high P deposit is about 215.9 kJ/mol. Bulk resistivity was measured using four-probe technique over a single coated fiber and the obtained value was around 3.2 μΩ-m. Tensile strength of these coated fibers were also carried out and observed that not much variation found in the strength of coated and uncoated fibers

Striatal dopamine D₂/₃ receptors in medication-naïve schizophrenia: an [¹²³I] IBZM SPECT study

BACKGROUND: The hyper-function of the striatal dopamine system has been suggested to underlie key pathophysiological mechanisms in schizophrenia. Moreover, patients have been observed to present a significant elevation of dopamine receptor availability compared to healthy controls. Although it is difficult to measure dopamine levels directly in humans, neurochemical imaging techniques such as single-photon emission computed tomography (SPECT) provide indirect indices of in vivo dopamine synthesis and release, and putative synaptic levels. METHODS: We focused on the role of dopamine postsynaptic regulation using [123I] iodobenzamide (IBZM) SPECT. We compared D2/3 receptor availability between 53 healthy controls and 21 medication-naive patients with recent-onset schizophrenia. RESULT: The mean specific striatal binding showed no significant difference between patients and controls (estimated difference = 0.001; 95% CI -0.11 to 0.11; F = 0.00, df = 1, 69; p = 0.99). There was a highly significant effect of age whereby IBZM binding declined with advancing age [estimated change per decade of age = -0.01(binding ratio); 95% CI -0.01 to -0.004; F = 11.5, df = 1, 69; p = 0.001]. No significant correlations were found between the mean specific striatal binding and psychopathological or cognitive rating scores. CONCLUSIONS: Medication-naïve patients with recent-onset schizophrenia have similar D2/3 receptor availability to healthy controls. We suggest that, rather than focusing exclusively on postsynaptic receptors, future treatments should target the presynaptic control of dopamine synthesis and release

Ambulatory blood pressure monitoring and morning surge in blood pressure in adult black and white South Africans

We examined whether there were differences in the circadian variation in blood pressure and the morning surge in blood pressure between black and white Africans. Clinic and ambulatory blood pressure data obtained from the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) study was examined (n = 406; 49% black African). Ambulatory blood pressure readings were fitted to a six-parameter double logistic equation to determine the power and rate of the morning surge in blood pressure. Multiple linear regression analysis was used to examine differences in blood pressure between black and white participants. Clinic and ambulatory blood pressure were higher in black participants throughout the day and night. In those taking medications, blood pressure was less well controlled in black subjects. Despite the higher systolic blood pressure, the day-night difference estimated by the logistic function was similar in black and white participants. However, the rate of rise and power in the morning surge in blood pressure was lower in black participants. We conclude that black participants of the SABPA study present with higher blood pressure throughout the day and night but have a lower power of the morning surge in blood pressure due to a slower morning rate of increase. Moreover, they had an increased prevalence of undiagnosed hypertension and, in those taking medication, were less likely to have their blood pressure controlled than their white counterparts

Systematic review and meta-analysis: prevalence of alcohol use among young people in eastern Africa.

OBJECTIVE: Systematic review and meta-analysis of published studies of alcohol use among young people (age 15-24 years) in eastern Africa to estimate prevalence of alcohol use and determine the extent of use of standardised screening questionnaires in alcohol studies. METHODS: Five databases (MEDLINE, EMBASE, Global Health, Africa-wide, and PsycINFO) were searched for publications until 30th June 2013. Results were summarised using the guidelines on preferred reporting items for systematic reviews and meta-analyses (PRISMA) and on quality assessment using the modified quality assessment tool for systematic reviews of observational studies (QATSO). Heterogeneity was assessed using the I(2) statistic (DerSimonian-Laird). RESULTS: We identified 2785 potentially relevant studies, of which 56 were eligible for inclusion. Only two studies (4%) used the standardised Alcohol Use Disorder Identification Test (AUDIT) questionnaire, and six studies (13%) used the Cut down, Annoyed, Guilt, Eye opener (CAGE) questionnaire. The reported median prevalence of alcohol use was ever-use 52% [interquartile range (IQR): 20-58%], use in the last month 28% (IQR: 17-37%), use in the last year 26% (IQR: 22-32%), and problem drinking as defined by CAGE or AUDIT 15% (IQR: 3-36%). We observed high heterogeneity between studies, with the highest prevalence of ever use of alcohol among university students (82%; 95%CI: 79-85%) and female sex workers (66%; 95%CI: 58-74%). Current use was most prevalent among male sex workers (69%; 95%CI: 63-75%). CONCLUSIONS: Reported alcohol use and problem drinking were common among diverse groups of young people in eastern Africa, indicating the urgent need for alcohol-focused interventions in this population. Few studies have used standardised alcohol screening questionnaires. Epidemiological research to investigate alcohol-focused interventions in young people should aim to apply such questionnaires that should be validated for use in this population

The Expression and Localization of N-Myc Downstream-Regulated Gene 1 in Human Trophoblasts

The protein N-Myc downstream-regulated gene 1 (NDRG1) is implicated in the regulation of cell proliferation, differentiation, and cellular stress response. NDRG1 is expressed in primary human trophoblasts, where it promotes cell viability and resistance to hypoxic injury. The mechanism of action of NDRG1 remains unknown. To gain further insight into the intracellular action of NDRG1, we analyzed the expression pattern and cellular localization of endogenous NDRG1 and transfected Myc-tagged NDRG1 in human trophoblasts exposed to diverse injuries. In standard conditions, NDRG1 was diffusely expressed in the cytoplasm at a low level. Hypoxia or the hypoxia mimetic cobalt chloride, but not serum deprivation, ultraviolet (UV) light, or ionizing radiation, induced the expression of NDRG1 in human trophoblasts and the redistribution of NDRG1 into the nucleus and cytoplasmic membranes associated with the endoplasmic reticulum (ER) and microtubules. Mutation of the phosphopantetheine attachment site (PPAS) within NDRG1 abrogated this pattern of redistribution. Our results shed new light on the impact of cell injury on NDRG1 expression patterns, and suggest that the PPAS domain plays a key role in NDRG1's subcellular distribution. © 2013 Shi et al

High-fidelity spin and optical control of single silicon-vacancy centres in silicon carbide

Scalable quantum networking requires quantum systems with quantum processing capabilities. Solid state spin systems with reliable spin–optical interfaces are a leading hardware in this regard. However, available systems suffer from large electron–phonon interaction or fast spin dephasing. Here, we demonstrate that the negatively charged silicon-vacancy centre in silicon carbide is immune to both drawbacks. Thanks to its 4A2 symmetry in ground and excited states, optical resonances are stable with near-Fourier-transform-limited linewidths, allowing exploitation of the spin selectivity of the optical transitions. In combination with millisecond-long spin coherence times originating from the high-purity crystal, we demonstrate high-fidelity optical initialization and coherent spin control, which we exploit to show coherent coupling to single nuclear spins with ∼1 kHz resolution. The summary of our findings makes this defect a prime candidate for realising memory-assisted quantum network applications using semiconductor-based spin-to-photon interfaces and coherently coupled nuclear spins

Estimation of progression of multi-state chronic disease using the Markov model and prevalence pool concept

<p>Abstract</p> <p>Background</p> <p>We propose a simple new method for estimating progression of a chronic disease with multi-state properties by unifying the prevalence pool concept with the Markov process model.</p> <p>Methods</p> <p>Estimation of progression rates in the multi-state model is performed using the E-M algorithm. This approach is applied to data on Type 2 diabetes screening.</p> <p>Results</p> <p>Good convergence of estimations is demonstrated. In contrast to previous Markov models, the major advantage of our proposed method is that integrating the prevalence pool equation (that the numbers entering the prevalence pool is equal to the number leaving it) into the likelihood function not only simplifies the likelihood function but makes estimation of parameters stable.</p> <p>Conclusion</p> <p>This approach may be useful in quantifying the progression of a variety of chronic diseases.</p

Identification and optimization of small molecule antagonists of vasoactive intestinal peptide receptor-1 (VIPR1)

Identification, synthesis and structure-activity relationship of small-molecule VIPR1 antagonists encompassing two chemical series are described