940 research outputs found
CMB Telescopes and Optical Systems
The cosmic microwave background radiation (CMB) is now firmly established as
a fundamental and essential probe of the geometry, constituents, and birth of
the Universe. The CMB is a potent observable because it can be measured with
precision and accuracy. Just as importantly, theoretical models of the Universe
can predict the characteristics of the CMB to high accuracy, and those
predictions can be directly compared to observations. There are multiple
aspects associated with making a precise measurement. In this review, we focus
on optical components for the instrumentation used to measure the CMB
polarization and temperature anisotropy. We begin with an overview of general
considerations for CMB observations and discuss common concepts used in the
community. We next consider a variety of alternatives available for a designer
of a CMB telescope. Our discussion is guided by the ground and balloon-based
instruments that have been implemented over the years. In the same vein, we
compare the arc-minute resolution Atacama Cosmology Telescope (ACT) and the
South Pole Telescope (SPT). CMB interferometers are presented briefly. We
conclude with a comparison of the four CMB satellites, Relikt, COBE, WMAP, and
Planck, to demonstrate a remarkable evolution in design, sensitivity,
resolution, and complexity over the past thirty years.Comment: To appear in: Planets, Stars and Stellar Systems (PSSS), Volume 1:
Telescopes and Instrumentatio
Filament Nucleation Tunes Mechanical Memory in Active Polymer Networks
Incorporating growth into contemporary material functionality presents a grand challenge in materials design. The F‐actin cytoskeleton is an active polymer network that serves as the mechanical scaffolding for eukaryotic cells, growing and remodeling in order to determine changes in cell shape. Nucleated from the membrane, filaments polymerize and grow into a dense network whose dynamics of assembly and disassembly, or “turnover,” coordinates both fluidity and rigidity. Here, the extent of F‐actin nucleation is varied from a membrane surface in a biomimetic model of the cytoskeleton constructed from purified protein. It is found that nucleation of F‐actin mediates the accumulation and dissipation of polymerization‐induced F‐actin bending energy. At high and low nucleation, bending energies are low and easily relaxed yielding an isotropic material. However, at an intermediate critical nucleation, stresses are not relaxed by turnover and the internal energy accumulates 100‐fold. In this case, high filament curvatures template further assembly of F‐actin, driving the formation and stabilization of vortex‐like topological defects. Thus, nucleation coordinates mechanical and chemical timescales to encode shape memory into active materials
Panel 4 : Report of the Microbiology Panel
Objective. To perform a comprehensive review of the literature from July 2011 until June 2015 on the virology and bacteriology of otitis media in children. Data Sources. PubMed database of the National Library of Medicine. Review Methods. Two subpanels comprising experts in the virology and bacteriology of otitis media were created. Each panel reviewed the relevant literature in the fields of virology and bacteriology and generated draft reviews. These initial reviews were distributed to all panel members prior to meeting together at the Post-symposium Research Conference of the 18th International Symposium on Recent Advances in Otitis Media, National Harbor, Maryland, in June 2015. A final draft was created, circulated, and approved by all panel members. Conclusions. Excellent progress has been made in the past 4 years in advancing our understanding of the microbiology of otitis media. Numerous advances were made in basic laboratory studies, in animal models of otitis media, in better understanding the epidemiology of disease, and in clinical practice. Implications for Practice. (1) Many viruses cause acute otitis media without bacterial coinfection, and such cases do not require antibiotic treatment. (2) When respiratory syncytial virus, metapneumovirus, and influenza virus peak in the community, practitioners can expect to see an increase in clinical otitis media cases. (3) Biomarkers that predict which children with upper respiratory tract infections will develop otitis media may be available in the future. (4) Compounds that target newly identified bacterial virulence determinants may be available as future treatment options for children with otitis media.Peer reviewe
Contextual factors influencing the urban mobility infrastructure interventions and policies for older adults in low- and middle-income countries: A realist review
Transportation is among the key aspects that influence active ageing. This realist review intends to understand the mechanisms of urban mobility infrastructure interventions and policies in low- and middle-income countries for older adults and to identify factors, which influenced the success or failure of interventions. We followed the steps suggested by Pawson and colleagues for a realist review. Electronic databases were searched from inception until August 2020. Studies were screened based on titles, abstracts and full text. The quality of included studies was assessed based on rigour and relevance. The evidence was obtained from 36 articles with diverse study designs conducted in 36 low- and middle-income countries. Findings were validated through stakeholder consultations from three low- and middle-income countries. Of the various individual factors identified, behaviour change communication interventions were low-cost, had a long-term impact and were efficient in increasing awareness among users to improve safety, social inclusion and about transport schemes for older adults. Improved transport infrastructure resulted in a shift from private to public transportation. For a sustainable urban transport infrastructure, good governance and involvement of stakeholders for planning and implementing transport interventions were considered necessary. Lack of evaluation, experience of transport planners, and inter-sectoral coordination were key challenges to successful interventions. The review highlighted a lack of older adult-specific transportation policies, and gender-targeted interventions for older women, suggesting a need for interventions and policies based on the contextual factors existing in a region
Entropy production rate is maximized in non-contractile actomyosin
The actin cytoskeleton is an active semi-flexible polymer network whose non-equilibrium properties coordinate both stable and contractile behaviors to maintain or change cell shape. While myosin motors drive the actin cytoskeleton out-of-equilibrium, the role of myosin-driven active stresses in the accumulation and dissipation of mechanical energy is unclear. To investigate this, we synthesize an actomyosin material in vitro whose active stress content can tune the network from stable to contractile. Each increment in activity determines a characteristic spectrum of actin filament fluctuations which is used to calculate the total mechanical work and the production of entropy in the material. We find that the balance of work and entropy does not increase monotonically and the entropy production rate is maximized in the non-contractile, stable state of actomyosin. Our study provides evidence that the origins of entropy production and activity-dependent dissipation relate to disorder in the molecular interactions between actin and myosin
Genetic diversity of Mycobacterium tuberculosis isolates from central India
Background & objectives: There is a paucity of data available on genetic biodiversity of Mycobacterium tuberculosis isolates from central India. The present study was carried out on isolates of M. tuberculosis cultured from diagnostic clinical samples of patients from Bhopal, central India, using spoligotyping as a method of molecular typing.
Methods: DNA was extracted from 340 isolates of M. tuberculosis from culture, confirmed as M. tuberculosis by molecular and biochemical methods and subjected to spoligotyping. The results were compared with the international SITVIT2 database.
Results: Sixty five different spoligo international type (SIT) patterns were observed. A total of 239 (70.3%) isolates could be clustered into 25 SITs. The Central Asian (CAS) and East African Indian (EAI) families were found to be the two major circulating families in this region. SIT26/CAS1_DEL was identified as the most predominant type, followed by SIT11/EAI3_IND and SIT288/CAS[2]. Forty (11.8%) unique (non-clustered) and 61 (17.9%) orphan isolates were identified in the study. There was no significant association of clustering with clinical and demographic characteristics of patients.
Interpretation & conclusions: Well established SITs were found to be predominant in our study. SIT26/CAS1_DEL was the most predominant type. However, the occurrence of a substantial number of orphan isolates may indicate the presence of active spatial and temporal evolutionary dynamics within the isolates of M. tuberculosis
Effect of Village-wide Use of Long-Lasting Insecticidal Nets on Visceral Leishmaniasis Vectors in India and Nepal: A Cluster Randomized Trial
Visceral leishmaniasis (VL) is a vector-borne disease causing at least 60,000 deaths each year amongst an estimated half million cases, and until recently there have been no significant initiatives to reduce this burden. However, in 2005, the governments of India, Bangladesh and Nepal signed a memorandum of understanding at the World Health Assembly in Geneva for the elimination of the disease by 2015. In the absence of an effective vaccine, the program will rely on the active detection and prompt treatment of cases throughout the endemic region, combined with a recurrent indoor residual spraying (IRS) of all villages at risk. Vector control programs based on IRS are notorious for failing to maintain comprehensive spray coverage over time owing to logistical problems and lack of compliance by householders. Long-lasting insecticidal nets (LNs) have been postulated as an alternative or complement to IRS. Here we describe how comprehensive coverage of LN in trial communities reduced the indoor density of sand flies by 25% compared to communities without LNs. This provides an indication that LNs could be usefully deployed as a component of the VL control program in the Indian subcontinent
Effects of antenatal multiple micronutrient supplementation on lung function in mid-childhood: follow-up of a double-blind randomised controlled trial in Nepal
A randomised trial of prenatal multiple micronutrient supplementation in Nepalese women increased birthweight and weight at 2 years of age in offspring, compared to those born to mothers who only received iron and folic acid supplements. Further follow-up of this cohort provided an opportunity to investigate the effect of antenatal multiple micronutrients on subsequent lung function by measuring spirometry at 7-9 years of age in C: hildren born during the trial. 841 children (80% of the cohort) were seen at mean±sd 8.5±0.4 years. Technically successful spirometry results were obtained in 793 (94.3%) children, 50% of whom had been randomised to micronutrient supplementation. Background characteristics, including anthropometry, were similar in the two allocation groups. Lung function was also similar, mean (95% CI) difference in z-scores (supplementation minus control) was -0.08 (-0.19-0.04), -0.05 (-0.17-0.06) and -0.04 (-0.15-0.07) for forced expiratory volume in 1 s (FEV1), forced vital capacity and FEV1/FVC, respectively. Compared with healthy white children, FEV1 and FVC in the "healthy" Nepalese children were ∼1 (∼13%) z-score lower, with no difference in FEV1/FVC. We conclude that, compared with routine iron and folic acid, multiple micronutrient supplementation during pregnancy has no effect on spirometric lung function in Nepalese children at 8.5 years of age
Evaluation of computerized health management information system for primary health care in rural India
<p>Abstract</p> <p>Background</p> <p>The Comprehensive Rural Health Services Project Ballabgarh, run by All India Institute of Medical Sciences (AIIMS), New Delhi has a computerized Health Management Information System (HMIS) since 1988. The HMIS at Ballabgarh has undergone evolution and is currently in its third version which uses generic and open source software. This study was conducted to evaluate the effectiveness of a computerized Health Management Information System in rural health system in India.</p> <p>Methods</p> <p>The data for evaluation were collected by in-depth interviews of the stakeholders i.e. program managers (authors) and health workers. Health Workers from AIIMS and Non-AIIMS Primary Health Centers were interviewed to compare the manual with computerized HMIS. A cost comparison between the two methods was carried out based on market costs. The resource utilization for both manual and computerized HMIS was identified based on workers' interviews.</p> <p>Results</p> <p>There have been no major hardware problems in use of computerized HMIS. More than 95% of data was found to be accurate. Health workers acknowledge the usefulness of HMIS in service delivery, data storage, generation of workplans and reports. For program managers, it provides a better tool for monitoring and supervision and data management. The initial cost incurred in computerization of two Primary Health Centers was estimated to be Indian National Rupee (INR) 1674,217 (USD 35,622). Equivalent annual incremental cost of capital items was estimated as INR 198,017 (USD 4213). The annual savings is around INR 894,283 (USD 11,924).</p> <p>Conclusion</p> <p>The major advantage of computerization has been in saving of time of health workers in record keeping and report generation. The initial capital costs of computerization can be recovered within two years of implementation if the system is fully operational. Computerization has enabled implementation of a good system for service delivery, monitoring and supervision.</p
Aldose Reductase Inhibition Prevents Metaplasia of Airway Epithelial Cells
BACKGROUND: Goblet cell metaplasia that causes mucus hypersecretion and obstruction in the airway lumen could be life threatening in asthma and chronic obstructive pulmonary disease patients. Inflammatory cytokines such as IL-13 mediate the transformation of airway ciliary epithelial cells to mucin-secreting goblet cells in acute as well as chronic airway inflammatory diseases. However, no effective and specific pharmacologic treatment is currently available. Here, we investigated the mechanisms by which aldose reductase (AR) regulates the mucus cell metaplasia in vitro and in vivo. METHODOLOGY/FINDINGS: Metaplasia in primary human small airway epithelial cells (SAEC) was induced by a Th2 cytokine, IL-13, without or with AR inhibitor, fidarestat. After 48 h of incubation with IL-13 a large number of SAEC were transformed into goblet cells as determined by periodic acid-schiff (PAS)-staining and immunohistochemistry using antibodies against Mucin5AC. Further, IL-13 significantly increased the expression of Mucin5AC at mRNA and protein levels. These changes were significantly prevented by treatment of the SAEC with AR inhibitor. AR inhibition also decreased IL-13-induced expression of Muc5AC, Muc5B, and SPDEF, and phosphorylation of JAK-1, ERK1/2 and STAT-6. In a mouse model of ragweed pollen extract (RWE)-induced allergic asthma treatment with fidarestat prevented the expression of IL-13, phosphorylation of STAT-6 and transformation of epithelial cells to goblet cells in the lung. Additionally, while the AR-null mice were resistant, wild-type mice showed goblet cell metaplasia after challenge with RWE. CONCLUSIONS: The results show that exposure of SAEC to IL-13 caused goblet cell metaplasia, which was significantly prevented by AR inhibition. Administration of fidarestat to mice prevented RWE-induced goblet cell metaplasia and AR null mice were largely resistant to allergen induced changes in the lung. Thus our results indicate that AR inhibitors such as fidarestat could be developed as therapeutic agents to prevent goblet cell metaplasia in asthma and related pathologies
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