1,138 research outputs found
QGP flow fluctuations and the characteristics of higher moments
The dynamical development of expanding Quark-gluon Plasma (QGP) flow is
studied in a 3+1D fluid dynamical model with a globally symmetric, initial
condition. We minimize fluctuations arising from complex dynamical processes at
finite impact parameters and from fluctuating random initial conditions to have
a conservative fluid dynamical background estimate for the statistical
distributions of the thermodynamical parameters. We also avoid a phase
transition in the equation of state, and we let the matter supercool during the
expansion.
Then central Pb+Pb collisions at TeV are studied in an
almost perfect fluid dynamical model, with azimuthally symmetric initial state
generated in a dynamical flux-tube model. The general development of
thermodynamical extensives are also shown for lower energies.
We observe considerable deviations from a thermal equilibrium source as a
consequence of the fluid dynamical expansion arising from a least fluctuating
initial state
Metastatic skull tumors: MRI features and a new conventional classification
Skull metastases are malignant bone tumors which are increasing in incidence. The objectives of this study were to characterize the MR imaging features, locations, and extent of metastatic skull tumors to determine the frequency of the symptomatic disease, and to assess patient outcomes. Between September 2002 and March 2008, 175 patients undergoing routine head MR imaging were found to have metastatic skull tumors. Contrast-enhanced study with fat suppression was used in some cases when required. Classification of metastases was simplified to three yes/no questions: first, with regard to location (either in the calvarium or in the cranial base); second, with regard to distribution within the plane of the cranial bone (either “circumscribed” meaning clearly demarcated and confined to one bone, or “diffuse” and likely to spread across a suture to another bone); and third, with regard to invasion (“intraosseous” in cranial bones only, or “invasive” spreading from the skull, either out into the scalp or inward to the dura and perhaps further in). Primary sites were breast cancer (55%), lung cancer (14%), prostate cancer (6%), malignant lymphoma (5%), and others (20%). The mean time from primary diagnosis to skull metastasis diagnosis was 71 months for cases of breast cancer, 26 months for prostate cancer, 9 months for lung cancer, and 4 months for malignant lymphoma. Calvarial circumscribed intraosseous metastases were found most frequently (27%). The patients were mainly asymptomatic. However, some patients suffered from local pain or cranial nerve palsies that harmed their quality of life. Treatment, mainly for symptomatic cases, was by local or whole-skull irradiation. Metastatic skull tumors are not rare, and most are calvarial circumscribed intraosseous tumors. MR images contribute to understanding their type, location, and multiplicity, and their relationship to the brain, cranial nerves, and dural sinuses. Radiation therapy improved the QOL of patients with neurological symptoms
Simulating the exchange of Majorana zero modes with a photonic system
The realization of Majorana zero modes is in the centre of intense theoretical and experimental investigations. Unfortunately, their exchange that can reveal their exotic statistics needs manipulations that are still beyond our experimental capabilities. Here we take an alternative approach. Through the Jordan-Wigner transformation, the Kitaev's chain supporting two Majorana zero modes is mapped to the spin-1/2 chain. We experimentally simulated the spin system and its evolution with a photonic quantum simulator. This allows us to probe the geometric phase, which corresponds to the exchange of two Majorana zero modes positioned at the ends of a three-site chain. Finally, we demonstrate the immunity of quantum information encoded in the Majorana zero modes against local errors through the simulator. Our photonic simulator opens the way for the efficient realization and manipulation of Majorana zero modes in complex architectures
Seroprevalence and correlates of HIV, syphilis, and hepatitis B and C virus among intrapartum patients in Kabul, Afghanistan
BackgroundLittle current information is available for prevalence of vertically-transmitted infections among the Afghan population. The purpose of this study is to determine prevalence and correlates of human immunodeficiency virus (HIV), syphilis, and hepatitis B and C infection among obstetric patients and model hepatitis B vaccination approaches in Kabul, Afghanistan.MethodsThis cross-sectional study was conducted at three government maternity hospitals in Kabul, Afghanistan from June through September, 2006. Consecutively-enrolled participants completed an interviewer-administered survey and whole blood rapid testing with serum confirmation for antibodies to HIV, T. pallidum, and HCV, and HBsAg. Descriptive data and prevalence of infection were calculated, with logistic regression used to identify correlates of HBV infection. Modeling was performed to determine impact of current and birth dose vaccination strategies on HBV morbidity and mortality.ResultsAmong 4452 women, prevalence of HBsAg was 1.53% (95% CI: 1.18 - 1.94) and anti-HCV was 0.31% (95% CI: 0.17 - 0.53). No cases of HIV or syphilis were detected. In univariate analysis, HBsAg was associated with husband's level of education (OR = 1.13, 95% CI: 1.01 - 1.26). Modeling indicated that introduction of birth dose vaccination would not significantly reduce hepatitis-related morbidity or mortality for the measured HBsAg prevalence.ConclusionIntrapartum whole blood rapid testing for HIV, syphilis, HBV, and HCV was acceptable to patients in Afghanistan. Though HBsAg prevalence is relatively low, periodic assessments should be performed to determine birth dose vaccination recommendations for this setting
Disulfide Bridges Remain Intact while Native Insulin Converts into Amyloid Fibrils
Amyloid fibrils are β-sheet-rich protein aggregates commonly found in the organs and tissues of patients with various amyloid-associated diseases. Understanding the structural organization of amyloid fibrils can be beneficial for the search of drugs to successfully treat diseases associated with protein misfolding. The structure of insulin fibrils was characterized by deep ultraviolet resonance Raman (DUVRR) and Nuclear Magnetic Resonance (NMR) spectroscopy combined with hydrogen-deuterium exchange. The compositions of the fibril core and unordered parts were determined at single amino acid residue resolution. All three disulfide bonds of native insulin remained intact during the aggregation process, withstanding scrambling. Three out of four tyrosine residues were packed into the fibril core, and another aromatic amino acid, phenylalanine, was located in the unordered parts of insulin fibrils. In addition, using all-atom MD simulations, the disulfide bonds were confirmed to remain intact in the insulin dimer, which mimics the fibrillar form of insulin
Interactions of malnutrition and immune impairment, with specific reference to immunity against parasites
KEY POINTS: 1. Clinical malnutrition is a heterogenous group of disorders including macronutrient deficiencies leading to body cell mass depletion and micronutrient deficiencies, and these often coexist with infectious and inflammatory processes and environmental problems. 2. There is good evidence that specific micronutrients influence immunity, particularly zinc and vitamin A. Iron may have both beneficial and deleterious effects depending on circumstances. 3. There is surprisingly slender good evidence that immunity to parasites is dependent on macronutrient intake or body composition
Efficient Cellular Release of Rift Valley Fever Virus Requires Genomic RNA
The Rift Valley fever virus is responsible for periodic, explosive epizootics throughout sub-Saharan Africa. The development of therapeutics targeting this virus is difficult due to a limited understanding of the viral replicative cycle. Utilizing a virus-like particle system, we have established roles for each of the viral structural components in assembly, release, and virus infectivity. The envelope glycoprotein, Gn, was discovered to be necessary and sufficient for packaging of the genome, nucleocapsid protein and the RNA-dependent RNA polymerase into virus particles. Additionally, packaging of the genome was found to be necessary for the efficient release of particles, revealing a novel mechanism for the efficient generation of infectious virus. Our results identify possible conserved targets for development of anti-phlebovirus therapies
Deletion of the Pichia pastoris KU70 Homologue Facilitates Platform Strain Generation for Gene Expression and Synthetic Biology
Targeted gene replacement to generate knock-outs and knock-ins is a commonly used method to study the function of unknown genes. In the methylotrophic yeast Pichia pastoris, the importance of specific gene targeting has increased since the genome sequencing projects of the most commonly used strains have been accomplished, but rapid progress in the field has been impeded by inefficient mechanisms for accurate integration. To improve gene targeting efficiency in P. pastoris, we identified and deleted the P. pastoris KU70 homologue. We observed a substantial increase in the targeting efficiency using the two commonly known and used integration loci HIS4 and ADE1, reaching over 90% targeting efficiencies with only 250-bp flanking homologous DNA. Although the ku70 deletion strain was noted to be more sensitive to UV rays than the corresponding wild-type strain, no lethality, severe growth retardation or loss of gene copy numbers could be detected during repetitive rounds of cultivation and induction of heterologous protein production. Furthermore, we demonstrated the use of the ku70 deletion strain for fast and simple screening of genes in the search of new auxotrophic markers by targeting dihydroxyacetone synthase and glycerol kinase genes. Precise knock-out strains for the well-known P. pastoris AOX1, ARG4 and HIS4 genes and a whole series of expression vectors were generated based on the wild-type platform strain, providing a broad spectrum of precise tools for both intracellular and secreted production of heterologous proteins utilizing various selection markers and integration strategies for targeted or random integration of single and multiple genes. The simplicity of targeted integration in the ku70 deletion strain will further support protein production strain generation and synthetic biology using P. pastoris strains as platform hosts
Does Lack of Multinutrient Supplementation During Early Pregnancy Increase Vulnerability to Alcohol-Related Preterm or Small-for-Gestational-Age Births?
The objective of this study was to assess whether women who do not take multinutrient supplements during early pregnancy are more susceptible to the effects of low-to-moderate alcohol consumption on preterm birth and small-for-gestational-age birth (SGA) compared to women who do take multinutrients. This analysis included 800 singleton live births to mothers from a cohort of pregnant women recruited for a population-based cohort study conducted in the Kaiser Permanente Medical Care Program in Northern California. Participants were recruited in their first trimester of pregnancy and information about their alcohol use and supplement intake during pregnancy was collected. Preterm birth (n = 53, 7%) was defined as a delivery prior to 37 completed weeks of gestation and SGA birth (n = 124, 16%) was defined as birth weight less than the 10th percentile for the infant’s gestational age and sex compared to US singleton live births. A twofold increase in the odds of SGA birth attributed to low-to-moderate alcohol intake was found among multinutrient supplement non-users (95% CI: 1.1, 5.3). Yet, among multinutrient supplement users, there was no increased risk of an SGA birth for women who drank low-to-moderately compared to women who abstained (aOR: 0.97, 95% CI: 0.6, 1.6). Similar results emerged for preterm birth. Our findings provide marginal evidence that multinutrient supplementation during early pregnancy may modify the risk of SGA births and preterm birth associated with alcohol consumption during pregnancy and may have important implications for pregnant women and women of child-bearing age. However, future research needs to be conducted
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