Diagnosis of tuberculosis in children: increased need for better methods.

In the last decade tuberculosis (TB) has reemerged as a major worldwide public health hazard with increasing incidence among adults and children. Although cases among children represent a small percentage of all TB cases, infected children are a reservoir from which many adult cases will arise. TB diagnosis in children usually follows discovery of a case in an adult, and relies on tuberculin skin testing, chest radiograph, and clinical signs and symptoms. However, clinical symptoms are nonspecific, skin testing and chest radiographs can be difficult to interpret, and routine laboratory tests are not helpful. Although more rapid and sensitive laboratory testing, which takes into account recent advances in molecular biology, immunology, and chromatography, is being developed, the results for children have been disappointing. Better techniques would especially benefit children and infants in whom early diagnosis is imperative for preventing progressive TB

LEED Holography applied to a complex superstructure: a direct view of the adatom cluster on SiC(111)-(3x3)

For the example of the SiC(111)-(3x3) reconstruction we show that a holographic interpretation of discrete Low Energy Electron Diffraction (LEED) spot intensities arising from ordered, large unit cell superstructures can give direct access to the local geometry of a cluster around an elevated atom, provided there is only one such prominent atom per surface unit cell. By comparing the holographic images obtained from experimental and calculated data we illuminate validity, current limits and possible shortcomings of the method. In particular, we show that periodic vacancies such as cornerholes may inhibit the correct detection of the atomic positions. By contrast, the extra diffraction intensity due to slight substrate reconstructions, as for example buckling, seems to have negligible influence on the images. Due to the spatial information depth of the method the stacking of the cluster can be imaged down to the fourth layer. Finally, it is demonstrated how this structural knowledge of the adcluster geometry can be used to guide the dynamical intensity analysis subsequent to the holographic reconstruction and necessary to retrieve the full unit cell structure.Comment: 11 pages RevTex, 6 figures, Phys. Rev. B in pres

Children of prisoners: exploring the impact of families' reappraisal of the role and status of the imprisoned parent on children's coping strategies

Qualitative data from a larger study on the impact of parental imprisonment in four countries found that children of prisoners face fundamentally similar psychological and social challenges. The ways that children cope, however, are influenced by the interpretative frame adopted by the adults around them, and by how issues of parental imprisonment are talked about in their families. This article argues that families have to reappraise their view of the imprisoned parent and then decide on their policy for how to deal with this publicly. Their approach may be based on openness and honesty or may emphasise privacy and secrecy, or a combination of these. Children are likely to be influenced by their parents'/carers' views, although these may cause conflict for them. Where parents/carers retain a positive view of the imprisoned parent, children are likely to benefit; where parents/carers feel issues of shame and stigma acutely, this is likely to be transmitted to their children. This is important for social workers and practitioners involved in supporting prisoners' families and for parenting programmes

Graphene formed on SiC under various environments: Comparison of Si-face and C-face

The morphology of graphene on SiC {0001} surfaces formed in various environments including ultra-high vacuum, 1 atm of argon, and 10^-6 to 10^-4 Torr of disilane is studied by atomic force microscopy, low-energy electron microscopy, and Raman spectroscopy. The graphene is formed by heating the surface to 1100 - 1600 C, which causes preferential sublimation of the Si atoms. The argon atmosphere or the background of disilane decreases the sublimation rate so that a higher graphitization temperature is required, thus improving the morphology of the films. For the (0001) surface, large areas of monolayer-thick graphene are formed in this way, with the size of these areas depending on the miscut of the sample. Results on the (000-1) surface are more complex. This surface graphitizes at a lower temperature than for the (0001) surface and consequently the growth is more three-dimensional. In an atmosphere of argon the morphology becomes even worse, with the surface displaying markedly inhomogeneous nucleation, an effect attributed to unintentional oxidation of the surface during graphitization. Use of a disilane environment for the (000-1) surface is found to produce improved morphology, with relatively large areas of monolayer-thick graphene.Comment: 22 pages, 11 figures, Proceedings of STEG-2 Conference; eliminated Figs. 4 and 7 from version 1, for brevity, and added Refs. 18, 29, 30, 31 together with associated discussio

The role of calcium ions in toxic cell injury.

Calcium ions have been increasingly implicated as a mediator of the mechanisms generating lethal cell injury under a variety of pathologic circumstances. An overview of the various roles suggested for such alterations in cellular calcium homeostasis is presented. The central role of plasma membrane damage in the genesis of irreversible cell injury is used to divide the postulated roles for calcium ions into two major mechanisms. On the one hand, calcium ions have been proposed as mediators of the functional consequences of plasma membrane injury. An influx of extracellular calcium ions across a damaged permeability barrier and down a steep concentration gradient may convert potentially reversible injury into irreversible injury. On the other hand, alterations in intracellular calcium homeostasis are postulated to participate in the mechanisms generating potentially lethal plasma membrane injury. The release of calcium stores sequestered within intracellular organelles raises the cytosolic concentration of free calcium, a process that may activate, in turn, a number of membrane-disruptive processes. The data supporting these two distinct actions of calcium are reviewed and discussed

Manifestation of quantum chaos on scattering techniques: application to low-energy and photo-electron diffraction intensities

Intensities of LEED and PED are analyzed from a statistical point of view. The probability distribution is compared with a Porter-Thomas law, characteristic of a chaotic quantum system. The agreement obtained is understood in terms of analogies between simple models and Berry's conjecture for a typical wavefunction of a chaotic system. The consequences of this behaviour on surface structural analysis are qualitatively discussed by looking at the behaviour of standard correlation factors.Comment: 5 pages, 4 postscript figures, Latex, APS, http://www.icmm.csic.es/Pandres/pedro.ht

The fine structure of the comparative

The paper provides evidence for a more articulated structure of the comparative as compared with the one in Bobaljik (2012). We propose to split up Bobaljik's cmpr head into two distinct heads, C1 and C2. Looking at Czech, Old Church Slavonic and English, we show that this proposal explains a range of facts about suppletion and allomorphy. A crucial ingredient of our analysis is the claim that adjectival roots are not a-categorial, but spell out adjectival functional structure. Specifically, we argue that adjectival roots come in various types, differing in the amount of functional structure they spell out. In order to correctly model the competition between roots, we further introduce a Faithfulness Restriction on Cyclic Override, which allows us to dispense with the Elsewhere Principle

Tuberculous meningitis in children: a forgotten public health emergency

Tuberculous meningitis (TBM) remains a major cause of morbidity and mortality in children with tuberculosis (TB), yet there are currently no estimates of the global burden of paediatric TBM. Due to frequent non-specific clinical presentation and limited and inadequate diagnostic tests, children with TBM are often diagnosed late or die undiagnosed. Even when diagnosed and treated, 20% of children with TBM die. Of survivors, the majority have substantial neurological disability with significant negative impact on children and their families. Surveillance data on this devastating form of TB can help to quantify the contribution of TBM to the overall burden, morbidity and mortality of TB in children and the epidemiology of TB more broadly. Paediatric TBM usually occurs shortly after primary infection with Mycobacterium tuberculosis and reflects ongoing TB transmission to children. In this article we explain the public health importance of paediatric TBM, discuss the epidemiology within the context of overall TB control and health system functioning and the limitations of current surveillance strategies. We provide a clear rationale for the benefit of improved surveillance of paediatric TBM using a TB care cascade framework to support monitoring and evaluation of paediatric TB, and TB control more broadly. Considering the public health implications of a diagnosis of TBM in children, we provide recommendations to strengthen paediatric TBM surveillance and outline how improved surveillance can help us identify opportunities for prevention, earlier diagnosis and improved care to minimize the impact of TBM on children globally

A METHODOLOGY FOR SIMULATION AND ASSESSMENT OF CONCENTRATED SOLAR POWER PLANTS

A thermal analysis of Concentrated Solar Power plants is conducted considering parabolic trough collectors (PTC), linear Fresnel collectors using direct steam generation scheme (LFC-DSG) and central receiver system using both molten nitrate salts (CRS-MNS) direct steam generation (CRS-DSG). The plant capacities were ranged from 50 to 800 MWth and the analysis focuses on the environmental conditions of selected locations in South America. Thus, the study considers a parametric analysis of the main design parameter for different plant scales, in terms of the thermal performance indicators as solar field aperture area, power block rating capacity and plant annual efficiencies. The annual production of the plants is calculated by using the Transient System Simulation program (TRNSYS), which considers a new component library developed for that purpose. This library is based in the open access models developed by the U.S National Renewable Energy Laboratory and currently employed by the System Advisor Model (SAM) program. In addition, a new fluid properties subroutine compatible with TRNSYS codes standards was developed, which uses the freeware CoolProp library. These approaches allowed to modify and create new configurations for CSP plants, e.g. thermal storage for the DSG scheme

Fluorine-19 MRI at 21.1 T: enhanced spin-lattice relaxation of perfluoro-15-crown-5-ether and sensitivity as demonstrated in ex vivo murine neuroinflammation

OBJECTIVE: Fluorine MR would benefit greatly from enhancements in signal-to-noise ratio (SNR). This study examines the sensitivity gain of (19)F MR that can be practically achieved when moving from 9.4 to 21.1 T. MATERIALS AND METHODS: We studied perfluoro-15-crown-5-ether (PFCE) at both field strengths (B(0)), as a pure compound, in the form of nanoparticles (NP) as employed to study inflammation in vivo, as well as in inflamed tissue. Brains, lymph nodes (LNs) and spleens were obtained from mice with experimental autoimmune encephalomyelitis (EAE) that had been administered PFCE NPs. All samples were measured at both B(0) with 2D-RARE and 2D-FLASH using (19)F volume radiofrequency resonators together. T(1) and T(2) of PFCE were measured at both B(0) strengths. RESULTS: Compared to 9.4 T, an SNR gain of > 3 was observed for pure PFCE and > 2 for PFCE NPs at 21.1 T using 2D-FLASH. A dependency of (19)F T(1) and T(2) relaxation on B(0) was demonstrated. High spatially resolved (19)F MRI of EAE brains and LNs at 21.1 T revealed signals not seen at 9.4 T. DISCUSSION: Enhanced SNR and T(1) shortening indicate the potential benefit of in vivo (19)F MR at higher B(0) to study inflammatory processes with greater detail