87 research outputs found
Latent tuberculosis among pregnant mothers in a resource poor setting in Northern Tanzania: a cross-sectional study
Untreated latent TB infection (LTBI) is a significant risk factor for active pulmonary tuberculosis, hence predisposing to adverse pregnancy outcomes and mother to child transmission. The prevalence of latent tuberculosis in pregnancy and its association, if any, with various socio-demographic, obstetric and clinical characteristics was evaluated. Northern Tanzania was chosen as the study site. In a cross-sectional study, a total of 286 pregnant women from 12 weeks gestational age to term were assessed. Screening was undertaken using an algorithm involving tuberculin skin testing, symptom screening in the form of a questionnaire, sputum testing for acid fast bacilli followed by shielded chest X-rays if indicated. HIV serology was also performed on consenting participants.\ud
Prevalence of latent infection ranged between 26.2% and 37.4% while HIV sero prevalence was 4.5%. After multivariate logistic analysis it was found that age, parity, body mass index, gestational age, and HIV sero status did not have any significant association with tuberculin skin test results. However certain ethnic groups were found to be less vulnerable to LTBI as compared to others (Chi square = 10.55, p = 0.03). All sputum smears for acid fast bacilli were negative. The prevalence of latent tuberculosis in pregnant women was found to be relatively high compared to that of the general population. In endemic areas, socio-demographic parameters alone are rarely adequate in identifying women susceptible to TB infection; therefore targeted screening should be conducted for all pregnant women at high risk for activation (especially HIV positive women). As opposed to the current policy of passive case detection, there appears to be an imminent need to move towards active screening. Ethnicity may provide important clues into genetic and cultural differences which predispose to latent tuberculosis, and is worth exploring further
A Bayesian view of the current status of dark matter direct searches
Bayesian statistical methods offer a simple and consistent framework for
incorporating uncertainties into a multi-parameter inference problem. In this
work we apply these methods to a selection of current direct dark matter
searches. We consider the simplest scenario of spin-independent elastic WIMP
scattering, and infer the WIMP mass and cross-section from the experimental
data with the essential systematic uncertainties folded into the analysis. We
find that when uncertainties in the scintillation efficiency of Xenon100 have
been accounted for, the resulting exclusion limit is not sufficiently
constraining to rule out the CoGeNT preferred parameter region, contrary to
previous claims. In the same vein, we also investigate the impact of
astrophysical uncertainties on the preferred WIMP parameters. We find that
within the class of smooth and isotropic WIMP velocity distributions, it is
difficult to reconcile the DAMA and the CoGeNT preferred regions by tweaking
the astrophysics parameters alone. If we demand compatibility between these
experiments, then the inference process naturally concludes that a high value
for the sodium quenching factor for DAMA is preferred.Comment: 37 pages, 14 figures and 7 tables. Replacement for matching the
version accepted for publicatio
Dark Matter attempts for CoGeNT and DAMA
Recently, the CoGeNT collaboration presented a positive signal for an annual
modulation in their data set. In light of the long standing annual modulation
signal in DAMA/LIBRA, we analyze the compatibility of both of these signal
within the hypothesis of dark matter (DM) scattering on nuclei, taking into
account existing experimental constraints. We consider the cases of elastic and
inelastic scattering with either spin-dependent or spin-independent coupling to
nucleons. We allow for isospin violating interactions as well as for light
mediators. We find that there is some tension between the size of the
modulation signal and the time-integrated event excess in CoGeNT, making it
difficult to explain both simultaneously. Moreover, within the wide range of DM
interaction models considered, we do not find a simultaneous explanation of
CoGeNT and DAMA/LIBRA compatible with constraints from other experiments.
However, in certain cases part of the data can be made consistent. For example,
the modulation signal from CoGeNT becomes consistent with the total rate and
with limits from other DM searches at 90% CL (but not with the DAMA/LIBRA
signal) if DM scattering is inelastic spin-independent with just the right
couplings to protons and neutrons to reduce the scattering rate on xenon.
Conversely the DAMA/LIBRA signal (but not CoGeNT) can be explained by
spin-dependent inelastic DM scattering.Comment: 20 pages, 9 figure
The ZEPLIN-III dark matter detector: instrument design, manufacture and commissioning
We present details of the technical design and manufacture of the ZEPLIN-III
dark matter experiment. ZEPLIN-III is a two-phase xenon detector which measures
both the scintillation light and the ionisation charge generated in the liquid
by interacting particles and radiation. The instrument design is driven by both
the physics requirements and by the technology requirements surrounding the use
of liquid xenon. These include considerations of key performance parameters,
such as the efficiency of scintillation light collection, restrictions placed
on the use of materials to control the inherent radioactivity levels,
attainment of high vacuum levels and chemical contamination control. The
successful solution has involved a number of novel design and manufacturing
features which will be of specific use to future generations of direct dark
matter search experiments as they struggle with similar and progressively more
demanding requirements.Comment: 25 pages, 19 figures. Submitted to Astropart. Phys. Some figures down
sampled to reduce siz
Direct Dark Matter Search using CCDs
There is currently vast evidence for Dark Matter (DM) from astronomical
observations. However, in spite of tremendous efforts by large experimental
groups, there is no confirmed direct detection of the dark matter in our
galaxy. Recent experimental results and theoretical developments suggest the
possibility of a DM particle with mass below 10 GeV, such a particle would
escape most of the direct searches due to the large thresholds for the
detection of nuclear recoils typically used. In this work we study the
possibility of a new Dark Matter search with an unprecedented low threshold for
the detection of nuclear recoils using high-resistivity CCD detectors (hr-CCD).
Due to their extremely low readout noise and the relatively large active mass,
these detectors present a unique opportunity in this field.Comment: paper presented at the Taup2009 Conferenc
CDMSlite: A Search for Low-Mass WIMPs using Voltage-Assisted Calorimetric Ionization Detection in the SuperCDMS Experiment
SuperCDMS is an experiment designed to directly detect Weakly Interacting
Massive Particles (WIMPs), a favored candidate for dark matter ubiquitous in
the Universe. In this paper, we present WIMP-search results using a
calorimetric technique we call CDMSlite, which relies on voltage- assisted
Luke-Neganov amplification of the ionization energy deposited by particle
interactions. The data were collected with a single 0.6 kg germanium detector
running for 10 live days at the Soudan Underground Laboratory. A low energy
threshold of 170 eVee (electron equivalent) was obtained, which allows us to
constrain new WIMP-nucleon spin-independent parameter space for WIMP masses
below 6 GeV/c2.Comment: 7 pages, 4 figure
Tumor Necrosis Factor-α +489G/A gene polymorphism is associated with chronic obstructive pulmonary disease
BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by a chronic inflammatory process, in which the pro-inflammatory cytokine Tumor Necrosis Factor (TNF)-α is considered to play a role. In the present study the putative involvement of TNF-α gene polymorphisms in pathogenesis of COPD was studied by analysis of four TNF-α gene polymorphisms in a Caucasian COPD population. METHODS: TNF-α gene polymorphisms at positions -376G/A, -308G/A, -238G/A, and +489G/A were examined in 169 Dutch COPD patients, who had a mean forced expiratory volume in one second (FEV1) of 37 ± 13%, and compared with a Dutch population control group of 358 subjects. RESULTS: The data showed that the TNF-α +489G/A genotype frequency tended to be different in COPD patients as compared to population controls, which was due to an enhanced frequency of the GA genotype. In line herewith, carriership of the minor allele was associated with enhanced risk of development of COPD (odds ratio = 1.9, p = 0.009). The other TNF-α gene polymorphisms studied revealed no discrimination between patients and controls. No differences in the examined four TNF-α polymorphisms were found between subtypes of COPD, which were stratified for the presence of radiological emphysema. However, comparison of the COPD subtypes with controls showed a significant difference in the TNF-α +489G/A genotype in patients without radiological emphysema (χ(2)-test: p < 0.025 [Bonferroni adjusted]), while no differences between COPD patients with radiological emphysema and controls were observed. CONCLUSION: Based on the reported data, it is concluded that COPD, and especially a subgroup of COPD patients without radiological emphysema, is associated with TNF-α +489G/A gene polymorphism
A three-drug nanoscale drug delivery system designed for preferential lymphatic uptake for the treatment of metastatic melanoma
Metastatic melanoma has a high mortality rate due to lymphatic progression of the disease. Current treatment is surgery followed by radiation and intravenous chemotherapy. However, drawbacks for current chemotherapeutics lie in the fact that they develop resistance and do not achieve therapeutic concentrations in the lymphatic system. We hypothesize that a three-drug nanoscale drug delivery system, tailored for lymphatic uptake, administered subcutaneously, will have decreased drug resistance and therefore offer better therapeutic outcomes. We prepared and characterized nanoparticles (NPs) with docetaxel, everolimus, and LY294002 in polyethyleneglycol-block-poly(ε-caprolactone) (PEG-PCL) polymer with different charge distributions by modifying the ratio of anionic and neutral end groups on the PEG block. These NPs are similarly sized (~48nm), with neutral, partially charged, or fully charged surface. The NPs are able to load ~2mg/mL of each drug and are stable for 24h. The NPs are assessed for safety and efficacy in two transgenic metastatic melanoma mouse models. All the NPs were safe in both models based on general appearance, weight changes, death, and blood biochemical analyses. The partially charged NPs are most effective in decreasing the number of melanocytes at both the proximal (sentinel) lymph node (LN) and the distal LN from the injection site. The neutral NPs are efficacious at the proximal LN, while the fully charged NPs have no effect on either LNs. Thus, our data indicates that the NP surface charge and lymphatic efficacy are closely tied to each other and the partially charged NPs have the highest potential in treating metastatic melanoma
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