Melting behavior of (Th,U)O2 and (Th,Pu)O2 mixed oxides

© 2016 Elsevier B.V.The melting behaviors of pure ThO2, UO2 and PuO2 as well as (Th,U)O2 and (Th,Pu)O2 mixed oxides (MOX) have been studied using molecular dynamics (MD) simulations. The MD calculated melting temperatures (MT) of ThO2, UO2 and PuO2 using two-phase simulations, lie between 3650-3675 K, 3050–3075 K and 2800–2825 K, respectively, which match well with experiments. Variation of enthalpy increments and density with temperature, for solid and liquid phases of ThO2, PuO2 as well as the ThO2 rich part of (Th,U)O2 and (Th,Pu)O2 MOX are also reported. The MD calculated MT of (Th,U)O2 and (Th,Pu)O2 MOX show good agreement with the ideal solidus line in the high thoria section of the phase diagram, and evidence for a minima is identified around 5 atom% of ThO2 in the phase diagram of (Th,Pu)O2 MOX

A study on the formation of crystalline phases during solidification and crystallization in the bulk metallic glass of Zr₅₃ Cu₂₁ A₁₀ Ni₈ Ti₈ composition

The present paper considers the formation of crystalline phases during solidification and crystallisation of the Zr53Cu21Al10Ni8Ti8 alloy. Solidification was carried out by a copper mould casting technique, which yielded a partially crystalline microstructure comprising a `big cube phase' in a dendritic morphology and a bct Zr2Ni phase. Detailed high-resolution microscopy was carried out to determine possible mechanisms for the formation of the crystalline phases. Based on microstructural examinations, it was established that the dendrites grew by the attachment of atomistic ledges. The bct Zr2Ni phase, formed during solidification and crystallisation, showed various types of faults depending on the crystallite size, and its crystallography was examined in detail. It has been shown that the presence of these faults could be explained by anti-site occupancy in the bct lattice of the Zr2Ni phase

Elicitation of Neutralizing Antibodies Directed against CD4-Induced Epitope(s) Using a CD4 Mimetic Cross-Linked to a HIV-1 Envelope Glycoprotein

The identification of HIV-1 envelope glycoprotein (Env) structures that can generate broadly neutralizing antibodies (BNAbs) is pivotal to the development of a successful vaccine against HIV-1 aimed at eliciting effective humoral immune responses. To that end, the production of novel Env structure(s) that might induce BNAbs by presentation of conserved epitopes, which are otherwise occluded, is critical. Here, we focus on a structure that stabilizes Env in a conformation representative of its primary (CD4) receptor-bound state, thereby exposing highly conserved “CD4 induced” (CD4i) epitope(s) known to be important for co-receptor binding and subsequent virus infection. A CD4-mimetic miniprotein, miniCD4 (M64U1-SH), was produced and covalently complexed to recombinant, trimeric gp140 envelope glycoprotein (gp140) using site-specific disulfide linkages. The resulting gp140-miniCD4 (gp140-S-S-M64U1) complex was recognized by CD4i antibodies and the HIV-1 co-receptor, CCR5. The gp140-miniCD4 complex elicited the highest titers of CD4i binding antibodies as well as enhanced neutralizing antibodies against Tier 1 viruses as compared to gp140 protein alone following immunization of rabbits. Neutralization against HIV-27312/V434M and additional serum mapping confirm the specific elicitation of antibodies directed to the CD4i epitope(s). These results demonstrate the utility of structure-based approach in improving immunogenic response against specific region, such as the CD4i epitope(s) here, and its potential role in vaccine application

Gene Expression Profiling and Molecular Characterization of Antimony Resistance in Leishmania amazonensis

Leishmania are unicellular microorganisms that can be transmitted to humans by the bite of sandflies. They cause a spectrum of diseases called leishmaniasis, which are classified as neglected tropical diseases by the World Health Organization. The treatment of leishmaniasis is based on the administration of antimony-containing drugs. These drugs have been used since 1947 and still constitute the mainstay for leishmaniasis treatment in several countries. One of the problems with these compounds is the emergence of resistance. Our work seeks to understand how these parasites become resistant to the drug. We studied antimony-resistant Leishmania amazonensis mutants. We analyzed gene expression at the whole genome level in antimony-resistant parasites and identified mechanisms used by Leishmania for resistance. This work could help us in developing new strategies for treatment in endemic countries where people are unresponsive to antimony-based chemotherapy. The identification of common mechanisms among different species of resistant parasites may also contribute to the development of diagnostic kits to identify and monitor the spread of resistance

Interview Language: A Proxy Measure for Acculturation Among Asian Americans in a Population-Based Survey

We examined health status and access to care among Asian Americans by the following acculturation indicators: nativity, percent lifetime in the US, self-rated English proficiency, and interview language, to assess whether any measure better distinguishes acculturation. Data from the 2003 California Health Interview Survey were used to study the sample of 4,170 US-born and foreign-born Asians by acculturation indicators. We performed t-tests to compare differences in demographics, health status and behaviors, and access to care between the foreign-born and US-born Asians, and between various classifications within foreign-born and the US-born Asian group. Our results showed that foreign-born Asians who interviewed in English more closely resembled US-born Asians than foreign-born Asians who interviewed in languages other than English. Compared to interview language, dichotomizing the sample by other acculturation indicators showed smaller differences between the divided groups. Interview language may serve as a better measure for acculturation especially among foreign-born populations with a high proportion of limited English proficiency. In immigrant public health research studies, interview language may be used as an important covariate for health disparities

Microarray Analysis of the Effect of Streptococcus equi subsp. zooepidemicus M-Like Protein in Infecting Porcine Pulmonary Alveolar Macrophage

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus), which belongs to Lancefield group C streptococci, is an important pathogen of domesticated species, causing septicemia, meningitis and mammitis. M-like protein (SzP) is an important virulence factor of S. zooepidemicus and contributes to bacterial infection and antiphagocytosis. To increase our knowledge of the mechanism of SzP in infection, we profiled the response of porcine pulmonary alveolar macrophage (PAM) to infection with S. zooepidemicus ATCC35246 wild strain (WD) and SzP-knockout strain (KO) using the Roche NimbleGen Porcine Genome Expression Array. We found SzP contributed to differential expression of 446 genes, with upregulation of 134 genes and downregulation of 312 genes. Gene Ontology category and KEGG pathway were analyzed for relationships among differentially expressed genes. These genes were represented in a variety of functional categories, including genes involved in immune response, regulation of chemokine production, signal transduction and regulation of apoptosis. The reliability of the data obtained from the microarray was verified by performing quantitative real-time PCR on 12 representative genes. The data will contribute to understanding of SzP mediated mechanisms of S. zooepidemicus pathogenesis

Hypothermia for moderate or severe neonatal encephalopathy in low-income and middle-income countries (HELIX): a randomised controlled trial in India, Sri Lanka, and Bangladesh

Background: Although therapeutic hypothermia reduces death or disability after neonatal encephalopathy in high-income countries, its safety and efficacy in low-income and middle-income countries is unclear. We aimed to examine whether therapeutic hypothermia alongside optimal supportive intensive care reduces death or moderate or severe disability after neonatal encephalopathy in south Asia. Methods: We did a multicountry open-label, randomised controlled trial in seven tertiary neonatal intensive care units in India, Sri Lanka, and Bangladesh. We enrolled infants born at or after 36 weeks of gestation with moderate or severe neonatal encephalopathy and a need for continued resuscitation at 5 min of age or an Apgar score of less than 6 at 5 min of age (for babies born in a hospital), or both, or an absence of crying by 5 min of age (for babies born at home). Using a web-based randomisation system, we allocated infants into a group receiving whole body hypothermia (33·5°C) for 72 h using a servo-controlled cooling device, or to usual care (control group), within 6 h of birth. All recruiting sites had facilities for invasive ventilation, cardiovascular support, and access to 3 Tesla MRI scanners and spectroscopy. Masking of the intervention was not possible, but those involved in the magnetic resonance biomarker analysis and neurodevelopmental outcome assessments were masked to the allocation. The primary outcome was a combined endpoint of death or moderate or severe disability at 18–22 months, assessed by the Bayley Scales of Infant and Toddler Development (third edition) and a detailed neurological examination. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, NCT02387385. Findings: We screened 2296 infants between Aug 15, 2015, and Feb 15, 2019, of whom 576 infants were eligible for inclusion. After exclusions, we recruited 408 eligible infants and we assigned 202 to the hypothermia group and 206 to the control group. Primary outcome data were available for 195 (97%) of the 202 infants in the hypothermia group and 199 (97%) of the 206 control group infants. 98 (50%) infants in the hypothermia group and 94 (47%) infants in the control group died or had a moderate or severe disability (risk ratio 1·06; 95% CI 0·87–1·30; p=0·55). 84 infants (42%) in the hypothermia group and 63 (31%; p=0·022) infants in the control group died, of whom 72 (36%) and 49 (24%; p=0·0087) died during neonatal hospitalisation. Five serious adverse events were reported: three in the hypothermia group (one hospital readmission relating to pneumonia, one septic arthritis, and one suspected venous thrombosis), and two in the control group (one related to desaturations during MRI and other because of endotracheal tube displacement during transport for MRI). No adverse events were considered causally related to the study intervention. Interpretation: Therapeutic hypothermia did not reduce the combined outcome of death or disability at 18 months after neonatal encephalopathy in low-income and middle-income countries, but significantly increased death alone. Therapeutic hypothermia should not be offered as treatment for neonatal encephalopathy in low-income and middle-income countries, even when tertiary neonatal intensive care facilities are available. Funding: National Institute for Health Research, Garfield Weston Foundation, and Bill & Melinda Gates Foundation. Translations: For the Hindi, Malayalam, Telugu, Kannada, Singhalese, Tamil, Marathi and Bangla translations of the abstract see Supplementary Materials section

Discovering Networks of Perturbed Biological Processes in Hepatocyte Cultures

The liver plays a vital role in glucose homeostasis, the synthesis of bile acids and the detoxification of foreign substances. Liver culture systems are widely used to test adverse effects of drugs and environmental toxicants. The two most prevalent liver culture systems are hepatocyte monolayers (HMs) and collagen sandwiches (CS). Despite their wide use, comprehensive transcriptional programs and interaction networks in these culture systems have not been systematically investigated. We integrated an existing temporal transcriptional dataset for HM and CS cultures of rat hepatocytes with a functional interaction network of rat genes. We aimed to exploit the functional interactions to identify statistically significant linkages between perturbed biological processes. To this end, we developed a novel approach to compute Contextual Biological Process Linkage Networks (CBPLNs). CBPLNs revealed numerous meaningful connections between different biological processes and gene sets, which we were successful in interpreting within the context of liver metabolism. Multiple phenomena captured by CBPLNs at the process level such as regulation, downstream effects, and feedback loops have well described counterparts at the gene and protein level. CBPLNs reveal high-level linkages between pathways and processes, making the identification of important biological trends more tractable than through interactions between individual genes and molecules alone. Our approach may provide a new route to explore, analyze, and understand cellular responses to internal and external cues within the context of the intricate networks of molecular interactions that control cellular behavior

lincRNAs act in the circuitry controlling pluripotency and differentiation

Although thousands of large intergenic non-coding RNAs (lincRNAs) have been identified in mammals, few have been functionally characterized, leading to debate about their biological role. To address this, we performed loss-of-function studies on most lincRNAs expressed in mouse embryonic stem (ES) cells and characterized the effects on gene expression. Here we show that knockdown of lincRNAs has major consequences on gene expression patterns, comparable to knockdown of well-known ES cell regulators. Notably, lincRNAs primarily affect gene expression in trans. Knockdown of dozens of lincRNAs causes either exit from the pluripotent state or upregulation of lineage commitment programs. We integrate lincRNAs into the molecular circuitry of ES cells and show that lincRNA genes are regulated by key transcription factors and that lincRNA transcripts bind to multiple chromatin regulatory proteins to affect shared gene expression programs. Together, the results demonstrate that lincRNAs have key roles in the circuitry controlling ES cell state.Broad InstituteHarvard UniversityNational Human Genome Research Institute (U.S.)Merkin Family Foundation for Stem Cell Researc