147 research outputs found

    Peer-to-Peer Networks and Computation: Current Trends and Future Perspectives

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    This research papers examines the state-of-the-art in the area of P2P networks/computation. It attempts to identify the challenges that confront the community of P2P researchers and developers, which need to be addressed before the potential of P2P-based systems, can be effectively realized beyond content distribution and file-sharing applications to build real-world, intelligent and commercial software systems. Future perspectives and some thoughts on the evolution of P2P-based systems are also provided

    Design and Analysis of New Shuffle Encryption Schemes for Multimedia

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    Securing the contents of visual data and multimedia requires specific design consideration for use in different applications. The major issue with this type of data has been occurrence of redundancy, at various places particularly in images, which makes data values repetitive at several places. The focus of this paper is on design of new shuffling schemes that can efficiently destroy redundancy in the visual data ensuring its secured transmission and distribution over public networks. Different variants of these shuffling schemes will be used as pre-processing schemes on multimedia data values especially in light weight devices using images. Standard as well as chaotic permutation and substitution schemes together with S-box rotation have been used to shuffle and map the plain data into random uncorrelated values via various variants of the presented schemes. For further improving the security, the processed data is encrypted using a computationally fast algorithm in its normal mode of operation. Security analysis using different types of images show that the proposed schemes satisfy the parameters required for securing visual contents even with very high redundancy.Defence Science Journal, 2012, 62(1), pp.159-166, DOI:http://dx.doi.org/10.14429/dsj.62.100

    Microbiological profile of early-onset neonatal sepsis in a tertiary care hospital in South India

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    Aims: To identify the microbiological profile of neonatal sepsis and antibiotic sensitivity patterns of various isolates in theNewborn Intensive Care Unit at a Tertiary Care Hospital in Karnataka. Materials and Methods: In this retrospective study, thelaboratory data of primary blood culture reports of 240 neonates admitted with clinical suspicion of early-onset sepsis, from April2014 to March 2016, were analyzed. Results: Total 240 samples were received during the study period, of which 40, (16%) werefound to be positive. Out of these, 18 (7.5%), 18 (7.5%), and 4 (1%) had Gram-positive, Gram-negative, and Candida infection,respectively. The most common organism noted among Gram-positive isolates was Staphylococcus aureus (22.5%), followed bycoagulase-negative staphylococci (12.5%) and Enterococcus (10%). Among Gram-negative isolates, Acinetobacter was the mostcommonly implicated organism (20%), followed by Klebsiella pneumoniae (12.5%), Escherichia coli (7.5%), and Pseudomonasaeruginosa (5%). Conclusion: This study emphasizes the need for close observation to be carried out at regular intervals to describethe various pathogens causing early-onset neonatal sepsis and their ever changing antibiotic sensitivity pattern which will provideuseful data to guide practice and policies on rational use of antibiotics

    Trajectory Correction Flight Control System using Pulsejeton an Artillery Rocket

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    A trajectory correction flight control system is small and durable, and consists of a lateralpulsejet ring mounted on the rocket body. The pulsejet ring consists of a finite number of individualpulsejets. Each pulsejet on the ring imparts a single, short-duration, large force to the rocket inthe plane normal to the rocket axis of symmetry. Lateral pulsejets are used by flight controlsystem to assist the rocket to follow a pre-specified (command) trajectory. The trajectory-trackingflight control system computes the position error by comparing the measured position of therocket with the pre-specified trajectory. In actual application, the position of the rocket couldbe measured using in-house inertial measurement unit (IMU) or by ground-based-tracking radarsystem located at the firing site. A study has been undertaken to explore the feasibility of reducingthe impact point dispersion of a routinely-used artillery rocket using lateral pulsejets coupledto a trajectory correction flight control system. Simulation studies have been conducted to arriveat tuning parameters, namely the tracking error window size, the required elapsed time betweenthe pulsejet firings and the angle of tolerance between the tracking error and the individualpulsejet force. Further, the robustness of the methodology wrt measurement noise has also beenevaluated.Defence Science Journal, 2008, 58(1), pp.15-33, DOI:http://dx.doi.org/10.14429/dsj.58.162

    Trends in Molecular Aspects and Therapeutic Applications of Drug Repurposing for Infectious Diseases

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    The pharmaceutical industry has undergone a severe economic crunch in antibiotic discovery research due to evolving bacterial resistance along with enormous time and money that gets consumed in de novo drug design and discovery strategies. Nevertheless, drug repurposing has evolved as an economically safer and excellent alternative strategy to identify approved drugs for new therapeutic indications. Virtual high throughput screening (vHTS) and phenotype-based high throughput screening (HTS) of approved molecules play a crucial role in identifying, developing, and repurposing old drug molecules into anti-infective agents either alone or in synergistic combination with antibiotic therapy. This chapter briefly explains the process of drug repurposing/repositioning in comparison to de novo methods utilizing vHTS and HTS technologies along with ‘omics- and poly-pharmacology-based drug repurposing strategies in the identification and development of anti-microbial agents. This chapter also gives an insightful survey of the intellectual property landscape on drug repurposing. Further, the challenges and applications of drug repurposing strategies in the discovery of anti-infective drugs are exemplified. The future perspectives of drug repurposing in the context of anti-infective agents are also discussed

    Virological failure, HIV-1 drug resistance, and early mortality in adults admitted to hospital in Malawi: an observational cohort study.

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    BACKGROUND: Antiretroviral therapy (ART) scale-up in sub-Saharan Africa combined with weak routine virological monitoring has driven increasing HIV drug resistance. We investigated ART failure, drug resistance, and early mortality among patients with HIV admitted to hospital in Malawi. METHODS: This observational cohort study was nested within the rapid urine-based screening for tuberculosis to reduce AIDS-related mortality in hospitalised patients in Africa (STAMP) trial, which recruited unselected (ie, irrespective of clinical presentation) adult (aged ≥18 years) patients with HIV-1 at admission to medical wards. Patients were included in our observational cohort study if they were enrolled at the Malawi site (Zomba Central Hospital) and were taking ART for at least 6 months at admission. Patients who met inclusion criteria had frozen plasma samples tested for HIV-1 viral load. Those with HIV-1 RNA of at least 1000 copies per mL had drug resistance testing by ultra-deep sequencing, with drug resistance defined as intermediate or high-level resistance using the Stanford HIVDR program. Mortality risk was calculated 56 days from enrolment. Patients were censored at death, at 56 days, or at last contact if lost to follow-up. The modelling strategy addressed the causal association between HIV multidrug resistance and mortality, excluding factors on the causal pathway (most notably, CD4 cell count, clinical signs of advanced HIV, and poor functional and nutritional status). FINDINGS: Of 1316 patients with HIV enrolled in the STAMP trial at the Malawi site between Oct 26, 2015, and Sept 19, 2017, 786 had taken ART for at least 6 months. 252 (32%) of 786 patients had virological failure (viral load ≥1000 copies per mL). Mean age was 41·5 years (SD 11·4) and 528 (67%) of 786 were women. Of 237 patients with HIV drug resistance results available, 195 (82%) had resistance to lamivudine, 128 (54%) to tenofovir, and 219 (92%) to efavirenz. Resistance to at least two drugs was common (196, 83%), and this was associated with increased mortality (adjusted hazard ratio 1·7, 95% CI 1·2-2·4; p=0·0042). INTERPRETATION: Interventions are urgently needed and should target ART clinic, hospital, and post-hospital care, including differentiated care focusing on patients with advanced HIV, rapid viral load testing, and routine access to drug resistance testing. Prompt diagnosis and switching to alternative ART could reduce early mortality among inpatients with HIV. FUNDING: Joint Global Health Trials Scheme of the Medical Research Council, UK Department for International Development, and Wellcome Trust

    Tuberculosis Incidence Rates during 8 Years of Follow-Up of an Antiretroviral Treatment Cohort in South Africa: Comparison with Rates in the Community

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    BACKGROUND: Although antiretroviral therapy (ART) is known to be associated with time-dependent reductions in tuberculosis (TB) incidence, the long-term impact of ART on incidence remains imprecisely defined due to limited duration of follow-up and incomplete CD4 cell count recovery in existing studies. We determined TB incidence in a South African ART cohort with up to 8 years of follow-up and stratified rates according to CD4 cell count recovery. We compared these rates with those of HIV-uninfected individuals living in the same community. METHODOLOGY/PRINCIPAL FINDINGS: Prospectively collected clinical data on patients receiving ART in a community-based cohort in Cape Town were analysed. 1544 patients with a median follow-up of 5.0 years (IQR 2.4-5.8) were included in the analysis. 484 episodes of incident TB (73.6% culture-confirmed) were diagnosed in 424 patients during 6506 person-years (PYs) of follow-up. The TB incidence rate during the first year of ART was 12.4 (95% CI 10.8-14.4) cases/100PYs and decreased to 4.92 (95% CI 3.64-8.62) cases/100PYs between 5 and 8 years of ART. During person-time accrued within CD4 cell strata 0-100, 101-200, 201-300, 301-400, 401-500, 501-700 and ≥700 cells/µL, TB incidence rates (95% CI) were 25.5 (21.6-30.3), 11.2 (9.4-13.5), 7.9 (6.4-9.7), 5.0 (3.9-6.6), 5.1 (3.8-6.8), 4.1 (3.1-5.4) and 2.7 (1.7-4.5) cases/100PYs, respectively. Overall, 75% (95% CI 70.9-78.8) of TB episodes were recurrent cases. Updated CD4 cell count and viral load measurements were independently associated with long-term TB risk. TB rates during person-time accrued in the highest CD4 cell count stratum (>700 cells/µL) were 4.4-fold higher that the rate in HIV uninfected individuals living in the same community (2.7 versus 0.62 cases/100PYs; 95%CI 0.58-0.65). CONCLUSIONS/SIGNIFICANCE: TB rates during long-term ART remained substantially greater than rates in the local HIV uninfected populations regardless of duration of ART or attainment of CD4 cell counts exceeding 700 cells/µL

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    14 Examples of How LLMs Can Transform Materials Science and Chemistry: A Reflection on a Large Language Model Hackathon

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    Chemistry and materials science are complex. Recently, there have been great successes in addressing this complexity using data-driven or computational techniques. Yet, the necessity of input structured in very specific forms and the fact that there is an ever-growing number of tools creates usability and accessibility challenges. Coupled with the reality that much data in these disciplines is unstructured, the effectiveness of these tools is limited. Motivated by recent works that indicated that large language models (LLMs) might help address some of these issues, we organized a hackathon event on the applications of LLMs in chemistry, materials science, and beyond. This article chronicles the projects built as part of this hackathon. Participants employed LLMs for various applications, including predicting properties of molecules and materials, designing novel interfaces for tools, extracting knowledge from unstructured data, and developing new educational applications. The diverse topics and the fact that working prototypes could be generated in less than two days highlight that LLMs will profoundly impact the future of our fields. The rich collection of ideas and projects also indicates that the applications of LLMs are not limited to materials science and chemistry but offer potential benefits to a wide range of scientific disciplines
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