500 research outputs found
CONFLLVM: A Compiler for Enforcing Data Confidentiality in Low-Level Code
We present an instrumenting compiler for enforcing data confidentiality in
low-level applications (e.g. those written in C) in the presence of an active
adversary. In our approach, the programmer marks secret data by writing
lightweight annotations on top-level definitions in the source code. The
compiler then uses a static flow analysis coupled with efficient runtime
instrumentation, a custom memory layout, and custom control-flow integrity
checks to prevent data leaks even in the presence of low-level attacks. We have
implemented our scheme as part of the LLVM compiler. We evaluate it on the SPEC
micro-benchmarks for performance, and on larger, real-world applications
(including OpenLDAP, which is around 300KLoC) for programmer overhead required
to restructure the application when protecting the sensitive data such as
passwords. We find that performance overheads introduced by our instrumentation
are moderate (average 12% on SPEC), and the programmer effort to port OpenLDAP
is only about 160 LoC.Comment: Technical report for CONFLLVM: A Compiler for Enforcing Data
Confidentiality in Low-Level Code, appearing at EuroSys 201
An evaluation of knowledge, attitude and practice of pharmacovigilance among prescribers in a teaching hospital of south India
Background: Adverse drug reactions (ADRs) represent a serious health problem. Effective generation of ADR related data helps in practicing evidence-based medicine and thus prevents many adverse drug reactions. Spontaneous reporting of ADRs has remained the major sources of information of pharmacovigilance. Underreporting of ADRs is a common problem. In order to improve the reporting rate, it is important to improve the Knowledge, Attitude and Practices (KAP) of the prescribers regarding ADR reporting and Pharmacovigilance. Hence this study was undertaken to assess the knowledge, attitude and practice regarding Pharmacovigilance among doctors of Shridevi Institute of Medical Sciences and Research Hospital, Tumkur, Karnataka.Methods: This was a cross sectional, observational, questionnaire based study conducted using a predesigned Knowledge Attitude Practice (KAP) questionnaire among 110 doctors. The completed KAP questionnaire was collected and data analyzed.Results: Most of the doctors (98.15%) accepted that reporting ADR is necessary. 67.31% agreed that ADR reporting is necessary for identifying safety of the drug and 94.44% agreed that pharmacovigilance should be taught in detail to health-care professionals. But there was a huge gap between the ADR experienced (80%), and ADR reported (25.45%) by the prescribers. Only 29.09% medical professionals have ever seen the ADR reporting form and only 16.36% respondents have been trained on reporting on ADR.Conclusions: Study revealed that the majority of the doctors had a good knowledge but poor attitude and practice of pharmacovigilance. They should be trained properly on ADR reporting to improve the current scenario in the pharmacovigilance program of the country
Effect of high intratesticular estrogen on global gene expression and testicular cell number in rats
<p>Abstract</p> <p>Background</p> <p>The identification of estrogen receptors alpha and beta and aromatase in the testis has highlighted the important role of estrogens in regulating spermatogenesis. There is a wealth of information on the deleterious effects of fetal and neonatal exposure of estrogens and xenoestrogens in the testis, including spermiation failure and germ cell apoptosis. However, very little is known about gene transcripts affected by exogenous estradiol exposure in the testis. The objective of the present study was to unveil global gene expression profiles and testicular cell number changes in rats after estradiol treatment.</p> <p>Methods</p> <p>17beta-estradiol was administered to adult male rats at a dose of 100 micrograms/kg body weight in saline daily for 10 days; male rats receiving only saline were used as controls. Microarray analysis was performed to examine global gene expression profiles with or without estradiol treatment. Real time RT-PCR was conducted to verify the microarray data. In silico promoter and estrogen responsive elements (EREs) analysis was carried out for the differentially expressed genes in response to estradiol. Quantitation of testicular cell number based on ploidy was also performed using flow cytometry in rats with or without estradiol treatment.</p> <p>Results</p> <p>We found that 221 genes and expressed sequence tags (ESTs) were differentially expressed in rat testes treated with estradiol compared to the control; the microarray data were confirmed by real time RT-PCR. Gene Ontology analysis revealed that a number of the differentially expressed genes are involved in androgen and xenobiotic metabolism, maintenance of cell cytoskeleton, endocytosis, and germ cell apoptosis. A total of 33 up-regulated genes and 67 down-regulated genes showed the presence of EREs. Flow cytometry showed that estradiol induced a significant decrease in 2n cells (somatic and germ cells) and 4n cells (pachytene spermatocytes) and a marked increase in the number of elongated and elongating spermatids.</p> <p>Conclusions</p> <p>This study provides a novel insight into the molecular basis for spermiation failure and apoptosis caused by 17beta-estradiol and it also offers new mechanisms by which adult exposure to environmental estrogens can affect spermatogenesis and fertility.</p
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Application of multiplexed ion mobility spectrometry towards the identification of host protein signatures of treatment effect in pulmonary tuberculosis.
RationaleThe monitoring of TB treatments in clinical practice and clinical trials relies on traditional sputum-based culture status indicators at specific time points. Accurate, predictive, blood-based protein markers would provide a simpler and more informative view of patient health and response to treatment.ObjectiveWe utilized sensitive, high throughput multiplexed ion mobility-mass spectrometry (IM-MS) to characterize the serum proteome of TB patients at the start of and at 8 weeks of rifamycin-based treatment. We sought to identify treatment specific signatures within patients as well as correlate the proteome signatures to various clinical markers of treatment efficacy.MethodsSerum samples were collected from 289 subjects enrolled in CDC TB Trials Consortium Study 29 at time of enrollment and at the end of the intensive phase (after 40 doses of TB treatment). Serum proteins were immunoaffinity-depleted of high abundant components, digested to peptides and analyzed for data acquisition utilizing a unique liquid chromatography IM-MS platform (LC-IM-MS). Linear mixed models were utilized to identify serum protein changes in the host response to antibiotic treatment as well as correlations with culture status end points.ResultsA total of 10,137 peptides corresponding to 872 proteins were identified, quantified, and used for statistical analysis across the longitudinal patient cohort. In response to TB treatment, 244 proteins were significantly altered. Pathway/network comparisons helped visualize the interconnected proteins, identifying up regulated (lipid transport, coagulation cascade, endopeptidase activity) and down regulated (acute phase) processes and pathways in addition to other cross regulated networks (inflammation, cell adhesion, extracellular matrix). Detection of possible lung injury serum proteins such as HPSE, significantly downregulated upon treatment. Analyses of microbiologic data over time identified a core set of serum proteins (TTHY, AFAM, CRP, RET4, SAA1, PGRP2) which change in response to treatment and also strongly correlate with culture status. A similar set of proteins at baseline were found to be predictive of week 6 and 8 culture status.ConclusionA comprehensive host serum protein dataset reflective of TB treatment effect is defined. A repeating set of serum proteins (TTHY, AFAM, CRP, RET4, SAA1, PGRP2, among others) were found to change significantly in response to treatment, to strongly correlate with culture status, and at baseline to be predictive of future culture conversion. If validated in cohorts with long term follow-up to capture failure and relapse of TB, these protein markers could be developed for monitoring of treatment in clinical trials and in patient care
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Volumetric laser endomicroscopy and its application to Barrett's esophagus: results from a 1,000 patient registry.
Volumetric laser endomicroscopy (VLE) uses optical coherence tomography (OCT) for real-time, microscopic cross-sectional imaging. A US-based multi-center registry was constructed to prospectively collect data on patients undergoing upper endoscopy during which a VLE scan was performed. The objective of this registry was to determine usage patterns of VLE in clinical practice and to estimate quantitative and qualitative performance metrics as they are applied to Barrett's esophagus (BE) management. All procedures utilized the NvisionVLE Imaging System (NinePoint Medical, Bedford, MA) which was used by investigators to identify the tissue types present, along with focal areas of concern. Following the VLE procedure, investigators were asked to answer six key questions regarding how VLE impacted each case. Statistical analyses including neoplasia diagnostic yield improvement using VLE was performed. One thousand patients were enrolled across 18 US trial sites from August 2014 through April 2016. In patients with previously diagnosed or suspected BE (894/1000), investigators used VLE and identified areas of concern not seen on white light endoscopy (WLE) in 59% of the procedures. VLE imaging also guided tissue acquisition and treatment in 71% and 54% of procedures, respectively. VLE as an adjunct modality improved the neoplasia diagnostic yield by 55% beyond the standard of care practice. In patients with no prior history of therapy, and without visual findings from other technologies, VLE-guided tissue acquisition increased neoplasia detection over random biopsies by 700%. Registry investigators reported that VLE improved the BE management process when used as an adjunct tissue acquisition and treatment guidance tool. The ability of VLE to image large segments of the esophagus with microscopic cross-sectional detail may provide additional benefits including higher yield biopsies and more efficient tissue acquisition. Clinicaltrials.gov NCT02215291
Proposing new variables for the identification of strategic groups in franchising
The identification of strategic groups in the Spanish franchising area is the
main aim of this study. The authors have added some new strategic variables (not
used before) to the study and have classified franchisors between sectors and
distribution strategy. The results reveal the existence of four perfectly differentiated
strategic groups (types of franchisors). One of the major implications of this study is
that the variables that build a strategic group vary depending on the respective sector the network operates in and its distribution strategy. This fact indicates that including sector and distribution strategy is absolutely necessary to achieve good classifications of franchisor type
Helicity within the vortex filament model
Kinetic helicity is one of the invariants of the Euler equations that is associated with the topology of vortex lines within the fluid. In superfluids, the vorticity is concentrated along vortex filaments. In this setting, helicity would be expected to acquire its simplest form. However, the lack of a core structure for vortex filaments appears to result in a helicity that does not retain its key attribute as a quadratic invariant. By defining a spanwise vector to the vortex through the use of a Seifert framing, we are able to introduce twist and henceforth recover the key properties of helicity. We present several examples for calculating internal twist to illustrate why the centreline helicity alone will lead to ambiguous results if a twist contribution is not introduced. Our choice of the spanwise vector can be expressed in terms of the tangential component of velocity along the filament. Since the tangential velocity does not alter the configuration of the vortex at later times, we are able to recover a similar equation for the internal twist angle to that of classical vortex tubes. Our results allow us to explain how a quasi-classical limit of helicity emerges from helicity considerations for individual superfluid vortex filaments
Formyl Peptide Receptor as a Novel Therapeutic Target for Anxiety-Related Disorders
Formyl peptide receptors (FPR) belong to a family of sensors of the immune system that detect microbe-associated molecules and inform various cellular and sensorial mechanisms to the presence of pathogens in the host. Here we demonstrate that Fpr2/3-deficient mice show a distinct profile of behaviour characterised by reduced anxiety in the marble burying and light-dark box paradigms, increased exploratory behaviour in an open-field, together with superior performance on a novel object recognition test. Pharmacological blockade with a formyl peptide receptor antagonist, Boc2, in wild type mice reproduced most of the behavioural changes observed in the Fpr2/3(-/-) mice, including a significant improvement in novel object discrimination and reduced anxiety in a light/dark shuttle test. These effects were associated with reduced FPR signalling in the gut as shown by the significant reduction in the levels of p-p38. Collectively, these findings suggest that homeostatic FPR signalling exerts a modulatory effect on anxiety-like behaviours. These findings thus suggest that therapies targeting FPRs may be a novel approach to ameliorate behavioural abnormalities present in neuropsychiatric disorders at the cognitive-emotional interface
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