Electric fields produced by electron irradiation of insulators in a low vacuum environment

We report on the properties of electric fields generated as a result of electron irradiation of dielectrics in a low vacuum scanning electron microscope. Individual field components produced by (i) ionized gas molecules located outside the sample surface and (ii) subsurface trapped charge were detected by measurements of changes in (i) primary electron landing energy and (ii) secondary electron (SE) emission current, respectively. The results provide experimental evidence for a recently proposed model of field-enhanced SE emission from electron irradiated insulators in a low vacuum environment [Toth et al., J. Appl. Phys. 91, 4479 (2002)]. Errors introduced into x-ray microanalysis by the electric fields generated by ionized gas molecules can be alleviated by minimizing the steady state ion concentration by the provision of efficient ion neutralization routes. It is demonstrated how this can be achieved using simple sample-electrode geometries. © 2002 American Institute of Physics. © 2002 American Institute of Physics

POTENTIAL AND UTILIZATION OF WATER RESOURCES IN THE ISLAND DEMERSAL AMBON - PROVINCE MALUKU

One of the fishery resources that have high economic value are demersal fisheries resources in deep sea waters. The results ofthis study found 22 demersal fish species with high economic value captured by fishermen. The results ofthe study found as many as 22 species, five fish stretcher 5 that can be foundin nearly all areas and fishing season. Five types of fish are:1) lencam (Lethrinus sp.), (2) kurisi (Etelis spp); (3) kerapu (Ephinephelus sp); (4) red snapper (Lutjanus spp); and 5) bubara fish (Caranx sp). The types of fish catches were found spread around the waters of Ambon Island. The potential at Maxsimum sustainable Yield (MSY) of fish grouper (Epinephelusspp) 572.02 15 753 tonnes with optimum effort trip.The average production of 178 919 tonnes currently.Thus the average utilization rate of groupers currently 31.27% or 68.72% untapped. If it is based on the MSY allowable catch for the fish species is 457.6 tons / year. MSY red snapper (Lutjanusspp) 146.83 2,631 tonnes with optimum effort trip. Average production is currently 67.704 tons. Thus the average utilization rate of the Red Snapper fish is currently 47.47%, or in other words the potential for red snapper untapped 52.52%. If it is based on the MSY allowable catch for the fish species is 117 464 tons / year. MSY bubara fish (Caranx sp) 270.60 tonnes with optimum effort 3630 trip with an average yield of 72.96 tons.</p

Early structural brain development in infants exposed to HIV and antiretroviral therapy in utero in a South African birth cohort

INTRODUCTION: There is a growing population of children who are HIV-exposed and uninfected (HEU) with the successful expansion of antiretroviral therapy (ART) use in pregnancy. Children who are HEU are at risk of delayed neurodevelopment; however, there is limited research on early brain growth and maturation. We aimed to investigate the effects of in utero exposure to HIV/ART on brain structure of infants who are HEU compared to HIV-unexposed (HU). METHODS: Magnetic resonance imaging using a T2-weighted sequence was undertaken in a subgroup of infants aged 2–6 weeks enrolled in the Drakenstein Child Health Study birth cohort, South Africa, between 2012 and 2015. Mother–child pairs received antenatal and postnatal HIV testing and ART per local guidelines. We compared subcortical and total grey matter volumes between HEU and HU groups using multivariable linear regression adjusting for infant age, sex, intracranial volume and socio-economic variables. We further assessed associations between brain volumes with maternal CD4 cell count and ART exposure. RESULTS: One hundred forty-six infants (40 HEU; 106 HU) with high-resolution images were included in this analysis (mean age 3 weeks; 50.7% male). All infants who were HEU were exposed to ART (88% maternal triple ART). Infants who were HEU had smaller caudate volumes bilaterally (5.4% reduction, p 0.2). Total grey matter volume was also reduced in infants who were HEU (2.1% reduction, p < 0.05). Exploratory analyses showed that low maternal CD4 cell count (<350 cells/mm3) was associated with decreased infant grey matter volumes. There was no relationship between timing of ART exposure and grey matter volumes. CONCLUSIONS: Lower caudate and total grey matter volumes were found in infants who were HEU compared to HU in the first weeks of life, and maternal immunosuppression was associated with reduced volumes. These findings suggest that antenatal HIV exposure may impact early structural brain development and improved antenatal HIV management may have the potential to optimize neurodevelopmental outcomes of children who are HEU

Sputum smear negative pulmonary tuberculosis: sensitivity and specificity of diagnostic algorithm

<p>Abstract</p> <p>Background</p> <p>The diagnosis of pulmonary tuberculosis in patients with Human Immunodeficiency Virus (HIV) is complicated by the increased presence of sputum smear negative tuberculosis. Diagnosis of smear negative pulmonary tuberculosis is made by an algorithm recommended by the National Tuberculosis and Leprosy Programme that uses symptoms, signs and laboratory results.</p> <p>The objective of this study is to determine the sensitivity and specificity of the tuberculosis treatment algorithm used for the diagnosis of sputum smear negative pulmonary tuberculosis.</p> <p>Methods</p> <p>A cross-section study with prospective enrollment of patients was conducted in Dar-es-Salaam Tanzania. For patients with sputum smear negative, sputum was sent for culture. All consenting recruited patients were counseled and tested for HIV. Patients were evaluated using the National Tuberculosis and Leprosy Programme guidelines and those fulfilling the criteria of having active pulmonary tuberculosis were started on anti tuberculosis therapy. Remaining patients were provided appropriate therapy. A chest X-ray, mantoux test, and Full Blood Picture were done for each patient. The sensitivity and specificity of the recommended algorithm was calculated. Predictors of sputum culture positive were determined using multivariate analysis.</p> <p>Results</p> <p>During the study, 467 subjects were enrolled. Of those, 318 (68.1%) were HIV positive, 127 (27.2%) had sputum culture positive for Mycobacteria Tuberculosis, of whom 66 (51.9%) were correctly treated with anti-Tuberculosis drugs and 61 (48.1%) were missed and did not get anti-Tuberculosis drugs. Of the 286 subjects with sputum culture negative, 107 (37.4%) were incorrectly treated with anti-Tuberculosis drugs. The diagnostic algorithm for smear negative pulmonary tuberculosis had a sensitivity and specificity of 38.1% and 74.5% respectively. The presence of a dry cough, a high respiratory rate, a low eosinophil count, a mixed type of anaemia and presence of a cavity were found to be predictive of smear negative but culture positive pulmonary tuberculosis.</p> <p>Conclusion</p> <p>The current practices of establishing pulmonary tuberculosis diagnosis are not sensitive and specific enough to establish the diagnosis of Acid Fast Bacilli smear negative pulmonary tuberculosis and over treat people with no pulmonary tuberculosis.</p

Conformal field theories in anti-de Sitter space

In this paper we discuss the dynamics of conformal field theories on anti-de Sitter space, focussing on the special case of the N=4 supersymmetric Yang-Mills theory on AdS_4. We argue that the choice of boundary conditions, in particular for the gauge field, has a large effect on the dynamics. For example, for weak coupling, one of two natural choices of boundary conditions for the gauge field leads to a large N deconfinement phase transition as a function of the temperature, while the other does not. For boundary conditions that preserve supersymmetry, the strong coupling dynamics can be analyzed using S-duality (relevant for g_{YM} >> 1), utilizing results of Gaiotto and Witten, as well as by using the AdS/CFT correspondence (relevant for large N and large 't Hooft coupling). We argue that some very specific choices of boundary conditions lead to a simple dual gravitational description for this theory, while for most choices the gravitational dual is not known. In the cases where the gravitational dual is known, we discuss the phase structure at large 't Hooft coupling.Comment: 57 pages, 1 figure. v2: fixed typo

Gene silencing in tick cell lines using small interfering or long double-stranded RNA

Gene silencing by RNA interference (RNAi) is an important research tool in many areas of biology. To effectively harness the power of this technique in order to explore tick functional genomics and tick-microorganism interactions, optimised parameters for RNAi-mediated gene silencing in tick cells need to be established. Ten cell lines from four economically important ixodid tick genera (Amblyomma, Hyalomma, Ixodes and Rhipicephalus including the sub-species Boophilus) were used to examine key parameters including small interfering RNA (siRNA), double stranded RNA (dsRNA), transfection reagent and incubation time for silencing virus reporter and endogenous tick genes. Transfection reagents were essential for the uptake of siRNA whereas long dsRNA alone was taken up by most tick cell lines. Significant virus reporter protein knockdown was achieved using either siRNA or dsRNA in all the cell lines tested. Optimum conditions varied according to the cell line. Consistency between replicates and duration of incubation with dsRNA were addressed for two Ixodes scapularis cell lines; IDE8 supported more consistent and effective silencing of the endogenous gene subolesin than ISE6, and highly significant knockdown of the endogenous gene 2I1F6 in IDE8 cells was achieved within 48 h incubation with dsRNA. In summary, this study shows that gene silencing by RNAi in tick cell lines is generally more efficient with dsRNA than with siRNA but results vary between cell lines and optimal parameters need to be determined for each experimental system

Validating MOSPA questionnaire for measuring physical activity in Pakistani women

BACKGROUND: Precise measurements of activity at a population level are important for monitoring trends and evaluating health promotion strategies. Few studies have assessed the measurement of physical activity in developing countries. The aim of this study was to validate the MOSPA (Monica Optional Study of Physical Activity) questionnaire which was developed for the WHO-Monitoring trends and determinants of cardiovasculr disease (MONICA) study sites. METHODS: The MOSPA questionnaire assesses energy expendtiture (EE) related to physical activity (employment, household work, transportation, and leisure time) over a one year period. This questionnaire has been described in the manuscript as the long term (LT) questionnaire. An adapted short term (ST) 5 day questionnaire was developed to assess convergent validity. Questionnaire data were compared with physical activity EE estimates from a Caltrac accelerometer and with body composition measures (height, weight and bioelectrical impedance) in 50 women from the Aga Khan University (AKU) hospital antenatal clinics, Pakistan. Other forms of EE i.e. resting EE and thermic effect of food were not assessd in this study. RESULTS: Subjects were aged 26 ± 3.8 years and were 16.1 ± 6.7 weeks pregnant. Their average weight was 58.8 ± 10.7 Kg. The average EE/day assessed by the Caltrac accelerometer, was 224 kcal and by MOSPA LT questionnaire it was 404 kcal. The questionnaires and Caltrac data were reasonably well correlated: r = 0.51 and r = 0.60 (P < 0.01) for LT and ST questionnaires respectively. Energy expenditure from questionnaire data was not correlated with body composition measures. CONCLUSION: The MOSPA questionnaire is useful in assessing physical activity levels in a sedentary population over a one year period

Effects of antenatal betamethasone on preterm human and mouse ductus arteriosus: comparison with baboon data.

BackgroundAlthough studies involving preterm infants ≤34 weeks gestation report a decreased incidence of patent ductus arteriosus after antenatal betamethasone, studies involving younger gestation infants report conflicting results.MethodsWe used preterm baboons, mice, and humans (≤276/7 weeks gestation) to examine betamethasone's effects on ductus gene expression and constriction both in vitro and in vivo.ResultsIn mice, betamethasone increased the sensitivity of the premature ductus to the contractile effects of oxygen without altering the effects of other contractile or vasodilatory stimuli. Betamethasone's effects on oxygen sensitivity could be eliminated by inhibiting endogenous prostaglandin/nitric oxide signaling. In mice and baboons, betamethasone increased the expression of several developmentally regulated genes that mediate oxygen-induced constriction (K+ channels) and inhibit vasodilator signaling (phosphodiesterases). In human infants, betamethasone increased the rate of ductus constriction at all gestational ages. However, in infants born ≤256/7 weeks gestation, betamethasone's contractile effects were only apparent when prostaglandin signaling was inhibited, whereas at 26-27 weeks gestation, betamethasone's contractile effects were apparent even in the absence of prostaglandin inhibitors.ConclusionsWe speculate that betamethasone's contractile effects may be mediated through genes that are developmentally regulated. This could explain why betamethasone's effects vary according to the infant's developmental age at birth

RNA:DNA hybrids are a novel molecular pattern sensed by TLR9.

The sensing of nucleic acids by receptors of the innate immune system is a key component of antimicrobial immunity. RNA:DNA hybrids, as essential intracellular replication intermediates generated during infection, could therefore represent a class of previously uncharacterised pathogen-associated molecular patterns sensed by pattern recognition receptors. Here we establish that RNA:DNA hybrids containing viral-derived sequences efficiently induce pro-inflammatory cytokine and antiviral type I interferon production in dendritic cells. We demonstrate that MyD88-dependent signalling is essential for this cytokine response and identify TLR9 as a specific sensor of RNA:DNA hybrids. Hybrids therefore represent a novel molecular pattern sensed by the innate immune system and so could play an important role in host response to viruses and the pathogenesis of autoimmune disease