579 research outputs found

    Genome-wide transcription analysis of interaction between the human macrophage and Mycobacterium tuberculosis during concurrent drug administration by conventional and novel methods

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    Targeted drug delivery to alveolar macrophages harboring Mycobacterium tuberculosis (Mtb) holds promise of high efficacy against pulmonary tuberculosis (TB). It was investigated whether inhalable microparticles (MP) can rescue macrophages from ‘alternative’ activation induced by pathogenic Mtb in addition to achieving targeted drug delivery. A genome-wide transcription analysis (Affymetrix HG-U133 Plus 2.0 DNA microarray) of THP-1 cell line derived macrophages was undertaken after exposing them to infection with 10 MOI of MTB H37Rv at 0, 12 and 24 hours post infection. The Molecular markers of macrophage bactericidal activity were assayed in THP-1- and primary human peripheral blood mononuclear cell (PBMC)-derived macrophages, in the presence or absence of soluble anti-tuberculosis drugs, drug-containing MP and blank MP. About 1,500 genes were differentially upregulated and about 500 genes differentially downregulated in response to various modes of treatment. Variations were also observed in the kinetics of gene expression. Cluster analysis indicated activation of several pathways related to innate immune response (cytokines, chemokines, receptors and ligands), apoptosis, cytoskeleton and membrane remodeling, general metabolism and general housekeeping. Some of these results were validated at the functional level, by studying caspase activities, concentrations and time-courses of effector molecules , rates/extents of apoptosis and nitrite oxide induction. Production of cytokines and NO, apoptosis, and bacterial survival were studied as pharmacodynamic outcomes. Cytokine responses of THP-1 derived macrophages were estimated. MP reversed suppression of tumor necrosis factor (TNF) induced by infection, and transiently upregulated γ-interferon (IFN-γ). Drug-free MP surprisingly induced IFN-γ, but not TNF. Primary cells responded to MP, regardless of drug content, by upregulation of NO; but THP-1-derived cells did not respond to blank MP. About 19% of infected cells exposed to MP underwent apoptosis as compared to ~11% cells treated with soluble drugs or blank MP. Cell death induced by blank MP was caspase-independent. Only drug-containing MP induced apoptosis through caspase-8 and caspase-9. Bacterial survival after different treatments varied between individuals. In the best case, while untreated infection resulted in survival of 900±141 colony forming units (CFU), treatment with soluble drugs, drug-containing MP and blank MP respectively, reduced CFU counts to 8.5± 0.7, 3±1.4 and 102±138.6. The results suggest a role of the drug delivery system in macrophage activation as a component of therapeutic strategy against TB

    Genetic Predisposition for Dermal Problems in Hexavalent Chromium Exposed Population

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    We studied the effect of genetic susceptibility on hexavalent chromium induced dermal adversities. The health status of population was examined from the areas of Kanpur (India) having the elevated hexavalent chromium levels in groundwater. Blood samples were collected for DNA isolation to conduct polymorphic determination of genes, namely: NQO1 (C609T), hOGG1 (C1245G), GSTT1, and GSTM1 (deletion). Symptomatic exposed subjects (n=38) were compared with asymptomatic exposed subjects (n=108) along with asymptomatic controls (n=148) from a non contaminated reference community. Exposed symptomatic group consisted of 36.8% subjects who were GSTM1 null genotyped as compared to asymptomatic where only 19.4% subjects were null. The exposed subjects with GSTM1 null genotype were more susceptible to dermal adversities in comparison with wild genotyped subjects (OR = 2.42; 95% CI = 1.071–5.451). Age, smoking, gender or duration of residence were not found to have any confounding effect towards this association. Association with other genes was not statistically significant, nonetheless, possible contribution by these genes cannot be ruled out. In conclusion, variation in the polymorphic status of GSTM1 gene may influence dermal outcomes among residents from Cr(VI) contaminated areas. Further studies are therefore, needed to examine these observations among different population groups

    Determination of Activation Energy of Relaxation Events in Composite Solid Propellants by Dynamic Mechanical Analysis

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    The shelf life of a composite solid propellant is one of the critical aspects for the usage of solid propellants. To assess the ageing behavior of the composite solid propellant, the activation energy is a key parameter. The activation energy is determined by analysis of visco-elastic response of the composite solid propellant when subjected to sinusoidal excitation. In the present study, dynamic mechanical analyzer was used to characterize six different types of propellants based on hydroxyl terminated polybutadiene, aluminium, ammonium perchlorate cured with toluene diisocyanate having burning rates varying from 5 mm/s to 25 mm/s at 7000 kPa. Each propellant sample was given a multi-frequency strain of 0.01 percent at three discrete frequencies (3.5 Hz, 11 Hz, 35 Hz) in the temperature range -80 °C to + 80 °C. It was observed that all the propellants have shown two relaxation events (α- and β- transition) in the temperature range -80 °C to +80 °C. The α-transition was observed between -66 °C and -51 °C and β-transition between 7 °C and 44 °C for the propellants studied. The activation energy for both transitions was determined by Arrhenius plot from dynamic properties measured at different frequencies and also by time temperature superposition principle using Williams-Landel-Ferry and Arrhenius temperature dependence equations. The data reveal that the activation energy corresponding to α-transition varies from 90 kJ/mol to 125 kJ/mol for R-value between 0.7 to 0.9 while for β-transition the values are from 75 kJ/mol to 92 kJ/mol. The activation energy corresponding to β-transition may be used to predict the useful life of solid propellant.Defence Science Journal, 2014, 64(2), pp. 173-178. DOI: http://dx.doi.org/10.14429/dsj.64.381

    Comparison between the Comet Assay and Fast Micromethod® for Measuring DNA Damage in HeLa Cells

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    The sensitivity and precision of the single cell gel electrophoresis (Comet) assay and Fast Micromethod® for DNA damage determinations in human HeLa cell line were compared. The first assay allows analysis of DNA breaks in individual cells while the second is a rapid and convenient procedure for DNA breaks determination in cell suspensions on single microplates. Both assays detect DNA strand breaks, alkali-labile sites and transient breaks occurring at sites of ongoing repair and might be applied for the assessment of surface water genotoxic potential as well as for clinical use. DNA damage in HeLa cells was induced by different doses of γ-rays generated by Cs137 (8 to 500 cGy), UV-C light (10 to 1000 J m-2) and by different concentrations of 4-nitroquinoline-V-oxide (0.026-2.6 μmol dm-3). Gamma rays induced a dose-depended response with the average Comet tail moment values from 7 mm for the negative control to 291 mm for 200 cGy, from 6.1 to 192 mm for 500 J m-2 of UV-C light and from 7.1 to 238 mm for 1.0 μmol dm-3 of 4-nitro-quinoline-N-oxide. The Fast Micromethod® strand scission factor varied from 0.010 for negative control to 0.701 for 500 cGy, from 0.019 to 1.196 for 1000 J m-2 and from 0.003 to 0.810 for 0.5 μmol dm-3 of 4-nitroquinoline-IV-oxide. Sensitivity was the same for both methods and in the case of 4-nitroquinoline-IV-oxide even better precision (lower variation coefficient) was achieved with the Fast Micromethod®. Since the time required for multiple analysis by the Fast Micromethod® is short (2 hours or less), its use in measuring DNA breakage in cells can be recommended for environmental genotoxicity monitoring

    Preformulation Studies of Pralidoxime Chloride for Formulation Development of Microspheres

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    Microspheres are one of the novel drug delivery system which possess several applications and are made up of assorted polymers. Microspheres can be defined as solid, approximately spherical particles ranging in size from 1 to 1000 μm range in diameter having a core of drug and entirely outer layers of polymers as coating material. They are made up of polymeric, waxy or other protective materials i.e. biodegradable synthetic polymer and modified natural products such as starches, gums, proteins, fats and waxes. Preformulation is a group of studies that focus on the physicochemical properties of a new drug candidate that could affect the drug performance and the development of a dosage form. This couldprovide important information for formulation design or support the need for molecular modification. Every drug has intrinsic chemical and physical properties which has been consider before development of pharmaceutical formulation. This property provides the framework for drugs combination with pharmaceutical ingredients in the fabrication of dosage form. Objective of preformulation study is to develop the elegant, stable, effective and safe dosage form by establishing kinetic rate profile, compatibility with the other ingredients and establish Physico-chemical parameter of new drug substances. The purpose of the present study was to systematically investigate some of the important physicochemical properties of pralidoxime chloride for preparation of microspheres. The physicochemical properties such as solubility, pKa, dissolution, melting point, assay development, excipient compatibility etc. of pralidoxime chloride was carried out. Before selection of excipients, the Preformulation study of drug pralidoxime is completed for successful formulation of microspheres. The result of Preformulation studies shows good flow properties, excipient compatibility, solubility efficiency and melting point. From this study we concluded that pralidoximewith HPMC and EC can be used to formulate pralidoxime microspheres for modified release. Keywords: Microspheres, Preformulation, Pralidoxime chloride, Physico-chemical parameter

    Orion Entry Handling Qualities Assessments

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    The Orion Command Module (CM) is a capsule designed to bring crew back from the International Space Station (ISS), the moon and beyond. The atmospheric entry portion of the flight is deigned to be flown in autopilot mode for nominal situations. However, there exists the possibility for the crew to take over manual control in off-nominal situations. In these instances, the spacecraft must meet specific handling qualities criteria. To address these criteria two separate assessments of the Orion CM s entry Handling Qualities (HQ) were conducted at NASA s Johnson Space Center (JSC) using the Cooper-Harper scale (Cooper & Harper, 1969). These assessments were conducted in the summers of 2008 and 2010 using the Advanced NASA Technology Architecture for Exploration Studies (ANTARES) six degree of freedom, high fidelity Guidance, Navigation, and Control (GN&C) simulation. This paper will address the specifics of the handling qualities criteria, the vehicle configuration, the scenarios flown, the simulation background and setup, crew interfaces and displays, piloting techniques, ratings and crew comments, pre- and post-fight briefings, lessons learned and changes made to improve the overall system performance. The data collection tools, methods, data reduction and output reports will also be discussed. The objective of the 2008 entry HQ assessment was to evaluate the handling qualities of the CM during a lunar skip return. A lunar skip entry case was selected because it was considered the most demanding of all bank control scenarios. Even though skip entry is not planned to be flown manually, it was hypothesized that if a pilot could fly the harder skip entry case, then they could also fly a simpler loads managed or ballistic (constant bank rate command) entry scenario. In addition, with the evaluation set-up of multiple tasks within the entry case, handling qualities ratings collected in the evaluation could be used to assess other scenarios such as the constant bank angle maintenance case. The 2008 entry assessment was divided into two sections (see Figure 1). Entry I was the first, high speed portion of a lunar return and Entry II was the second, lower speed portion of a lunar return, which is similar (but not identical) to a typical ISS return

    Humidity assay for studying plant-pathogen interactions in miniature controlled discrete humidity environments with good throughput

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    This paper reports a highly economical and accessible approach to generate different discrete relative humidity conditions in spatially separated wells of a modified multi-well plate for humidity assay of plant-pathogen interactions with good throughput. We demonstrated that a discrete humidity gradient could be formed within a few minutes and maintained over a period of a few days inside the device. The device consisted of a freeway channel in the top layer, multiple compartmented wells in the bottom layer, a water source, and a drying agent source. The combinational effects of evaporation, diffusion, and convection were synergized to establish the stable discrete humidity gradient. The device was employed to study visible and molecular disease phenotypes of soybean in responses to infection by Phytophthora sojae, an oomycete pathogen, under a set of humidity conditions, with two near-isogenic soybean lines, Williams and Williams 82, that differ for a Phytophthora resistance gene (Rps1-k). Our result showed that at 63% relative humidity, the transcript level of the defense gene GmPR1 was at minimum in the susceptible soybean line Williams and at maximal level in the resistant line Williams 82 following P. sojae CC5C infection. In addition, we investigated the effects of environmental temperature, dimensional and geometrical parameters, and other configurational factors on the ability of the device to generate miniature humidity environments. This work represents an exploratory effort to economically and efficiently manipulate humidity environments in a space-limited device and shows a great potential to facilitate humidity assay of plant seed germination and development, pathogen growth, and plant-pathogen interactions. Since the proposed device can be easily made, modified, and operated, it is believed that this present humidity manipulation technology will benefit many laboratories in the area of seed science, plant pathology, and plant-microbe biology, where humidity is an important factor that influences plant disease infection, establishment, and development

    Scaling Reliably: Improving the Scalability of the Erlang Distributed Actor Platform

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    Distributed actor languages are an effective means of constructing scalable reliable systems, and the Erlang programming language has a well-established and influential model. While the Erlang model conceptually provides reliable scalability, it has some inherent scalability limits and these force developers to depart from the model at scale. This article establishes the scalability limits of Erlang systems and reports the work of the EU RELEASE project to improve the scalability and understandability of the Erlang reliable distributed actor model. We systematically study the scalability limits of Erlang and then address the issues at the virtual machine, language, and tool levels. More specifically: (1) We have evolved the Erlang virtual machine so that it can work effectively in large-scale single-host multicore and NUMA architectures. We have made important changes and architectural improvements to the widely used Erlang/OTP release. (2) We have designed and implemented Scalable Distributed (SD) Erlang libraries to address language-level scalability issues and provided and validated a set of semantics for the new language constructs. (3) To make large Erlang systems easier to deploy, monitor, and debug, we have developed and made open source releases of five complementary tools, some specific to SD Erlang. Throughout the article we use two case studies to investigate the capabilities of our new technologies and tools: a distributed hash table based Orbit calculation and Ant Colony Optimisation (ACO). Chaos Monkey experiments show that two versions of ACO survive random process failure and hence that SD Erlang preserves the Erlang reliability model. While we report measurements on a range of NUMA and cluster architectures, the key scalability experiments are conducted on the Athos cluster with 256 hosts (6,144 cores). Even for programs with no global recovery data to maintain, SD Erlang partitions the network to reduce network traffic and hence improves performance of the Orbit and ACO benchmarks above 80 hosts. ACO measurements show that maintaining global recovery data dramatically limits scalability; however, scalability is recovered by partitioning the recovery data. We exceed the established scalability limits of distributed Erlang, and do not reach the limits of SD Erlang for these benchmarks at this scal
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