320 research outputs found

    Fundamentals of dry coating in fluidized bed

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    This thesis is devoted to the study of a novel dry coating method in fluidized bed - Dry Coating of Particles in Spouted bed (DCPS). The main objectives of this work were to study the feasibility of the process, both quantitatively and qualitatively, and to compare the results with coating by conventional mechanical mixing. Aerosol mechanics is applied to account for the following: 1) collision between the guest and host particles in a spouted bed (analysis of guest-host particle inertial fluid-dynamic interaction), and 2) to show how collision efficiency of guest particles with host particles affects the coating efficiency. An equation for relating coating efficiency to collision efficiency was derived. This equation predicts high coating efficiency for large-size guest aggregates and low coating efficiency for small-size guest aggregates. The experimental results confirmed the above predictions. It was established that large-size guest aggregates deformed during collision in the spouted bed resulting in patches over the surface of the host. This deposition mode results in large surface coverage. It was also established that the relative variation of coating among coated host particles by this method was very low. The relative variation of patches over the coated host surface was very low and from literature survey it was found that single particle coating resulted in non-uniform distribution over host particle surface [10]. Dry coating, by conventional mechanical mixing was investigated and compared with the novel dry coating method proposed in this thesis. This investigation demonstrated that coating by mechanical mixing resulted in non-uniform coating and harmful manifestation of guest particle agglomeration during the mixing process

    Thermoelectrics: Ecological Profile and Fundamental Principles for Sustainability

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    The need for efficient energy conversion and utilization has magnified on account of global environmental concerns, leading to a dramatic rise in focus on technologies that can accomplish such enhanced efficiencies. In this context, thermoelectrics (TEs) have emerged as a prominent platform on account of rigorous research that has enabled a significant leap in their conversion efficiencies, which enhances their potential to lower fossil fuel consumption. However, the advent of novel TEs has been accompanied by growing concerns about the use of scarce and toxic constituent elements in most of these materials/systems, raising questions about their eco-friendliness. While these concerns must be suitably addressed, the very nature of looking at TEs solely in terms of either benefits during their usage, or at issues with their constituents, confines the notion of sustainability to one or few stages of their life cycle. This creates doubts about the traditional claims of TEs being ecofriendly, since other environmental issues associated with their life cycle, such as impacts caused by their production or end-of-life treatment, remain neglected. These gaps hinder a true assessment of ecological credentials of TEs as an energy harvesting platform, and also make it difficult to provide adequate directions to policymakers and other stakeholders on the nature of steps required to make this platform ecologically suitable and economically viable. To ameliorate these gaps, this work explores the environmental profile of TEs using life cycle assessment (LCA). TE devices – modules and generators – were evaluated for environmental performance across their life cycle for three applications differing in their nature of waste heat emission and mobility. These were: (a) baseload coal-based power plant (static, constant emission); (b) peak load natural gas-based power plants (static, periodic emission); and (c) automobiles (mobile, intermittent emission). For all end-uses, TEs were assessed on various impacts. The first-ever exhaustive inventory analysis to date was conducted for production of TE devices, while three end-of-life (EOL) scenarios were considered to determine the benefits and pitfalls of recycling TEs as these use scarce constituents. Subsequently, the results from these LCA analyses were used to distill key findings and postulate principles for developing sustainable thermoelectrics. LCA analysis of TEs showed that both high electricity consumption for TE processing and use of constituent elements that emit toxic waste during their extraction and refining, caused the bulk of their production-related impacts. Further, while TE devices were observed to be environmentally sound for applications involving continuous waste heat emission (coal-based power), they showed ineffectiveness for periodic (gas-based electricity) and intermittent waste heat emission (automobiles) to varying degrees. In addition, recycling of TEs was seen to have moderate influence on their ecological output, with heat exchanger-based components playing a more significant role. Lastly, using the results from LCA analyses, eight sustainability principles were postulated for TEs encompassing their entire life cycle, that can guide policymakers to work with other stakeholders on enhancing overall eco-friendliness of this platform

    Operating system profiling via latency analysis

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    Operating systems are complex and their behavior depends on many factors. Source code, if available, does not directly help one to understand the OS’s behavior, as the behavior depends on actual workloads and external inputs. Runtime profiling is a key technique to prove new concepts, debug problems, and optimize performance. Unfortunately, existing profiling methods are lacking in important areas—they do not provide enough information about the OS’s behavior, they require OS modification and therefore are not portable, or they incur high overheads thus perturbing the profiled OS. We developed OSprof: a versatile, portable, and efficient OS profiling method based on latency distributions analysis. OSprof automatically selects important profiles for subsequent visual analysis. We have demonstrated that a suitable workload can be used to profile virtually any OS component. OSprof is portable because it can intercept operations and measure OS behavior from user-level or from inside the kernel without requiring source code. OSprof has typical CPU time overheads below 4%. In this paper we describe our techniques and demonstrate their usefulness through a series of profiles conducted on Linux, FreeBSD, and Windows, including client/server scenarios. We discovered and investigated a number of interesting interactions, including scheduler behavior, multi-modal I/O distributions, and a previously unknown lock contention, which we fixed.

    Discriminating early-stage diabetic retinopathy with subjective and objective perimetry

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    Introduction: To prevent progression of early-stage diabetic retinopathy, we need functional tests that can distinguish multiple levels of neural damage before classical vasculopathy. To that end, we compared multifocal pupillographic objective perimetry (mfPOP), and two types of subjective automated perimetry (SAP), in persons with type 2 diabetes (PwT2D) with either no retinopathy (noDR) or mild to-moderate non-proliferative retinopathy (mmDR). Methods: Both eyes were assessed by two mfPOP test methods that present stimuli within either the central ±15° (OFA15) or ±30° (OFA30), each producing per-region sensitivities and response delays. The SAP tests were 24-2 Short Wavelength Automated Perimetry and 24-2 Matrix perimetry. Results: Five of eight mfPOP global indices were significantly different between noDR and mmDR eyes, but none of the equivalent measures differed for SAP. Per-region mfPOP identified significant hypersensitivity and longer delays in the peripheral visual field, verifying earlier findings. Diagnostic power for discrimination of noDR vs. mmDR, and normal controls vs. PwT2D, was much higher for mfPOP than SAP. The mfPOP per-region delays provided the best discrimination. The presence of localized rather than global changes in delay ruled out iris neuropathy as a major factor. Discussion: mfPOP response delays may provide new surrogate endpoints for studies of interventions for early-stage diabetic eye damage.</p

    Understanding needs of stakeholders and outcomes desired from a home-based intervention program for “difficult to treat” schizophrenia and related disorders : a qualitative study

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    Background: We aimed to understand the needs of service users – families and patients with schizophrenia and related disorders, and mental health professionals (MHPs) and expectations from a home-based psychosocial intervention program in Indian setting. Materials and Methods: We conducted four focus group discussions (FGDs) with families, patients with schizophrenia and related disorders and MHPs. Two FGDs were conducted with families and one each with the patients and MHPs. Participants in families and MHP group were asked about their primary concerns in caring for the patients, perceived needs of patients and the areas that can be targeted through a home-based psychosocial intervention program. All FGDs were audio-recorded and verbatim transcribed. Content analysis of the data was done to obtain a final list of needs and expected outcomes from a psychosocial intervention supported by families. Results: Six key priority needs were identified for intervention: medication adherence, activities of daily living, promoting physical health, engagement in meaningful work, building of social and support networks and information about all aspects of illness. Priority outcomes identified by MHPs were mostly clinical like symptom reduction, fewer rehospitalisation while families and patients focused more on psychosocial outcomes, such as improvement of wellbeing, having relationships, engagement in meaningful activities, better organization of the day, increased self-respect, reduced stress, lesser interference, and critical comments. All groups suggested that book or mobile app or video could be used. Conclusion: This qualitative study shows that while both clinicians and service users consider recovery from schizophrenia and related disorders to be important, they differ on what they prioritise

    Pathways to care in first-episode psychosis in low-resource settings: Implications for policy and practice.

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    Developing countries such as India face a major mental health care gap. Delayed or inadequate care can have a profound impact on treatment outcomes. We compared pathways to care in first episode psychosis (FEP) between North and South India to inform solutions to bridge the treatment gap. Cross-sectional observation study of 'untreated' FEP patients (n = 177) visiting a psychiatry department in two sites in India (AIIMS, New Delhi and SCARF, Chennai). We compared duration of untreated psychosis (DUP), first service encounters, illness attributions and socio-demographic factors between patients from North and South India. Correlates of DUP were explored using logistic regression analysis (DUP ≥ 6 months) and generalised linear models (DUP in weeks). Patients in North India had experienced longer DUP than patients in South India (β = 17.68, p < 0.05). The most common first encounter in North India was with a faith healer (45.7%), however, this contact was not significantly associated with longer DUP. Visiting a faith healer was the second most common first contact in South India (23.6%) and was significantly associated with longer DUP (Odds Ratio: 6.84; 95% Confidence Interval: 1.77, 26.49). Being in paid employment was significantly associated with shorter DUP across both sites. Implementing early intervention strategies in a diverse country like India requires careful attention to local population demographics; one size may not fit all. A collaborative relationship between faith healers and mental health professionals could help with educational initiatives and to provide more accessible care. [Abstract copyright: Copyright © 2023. Published by Elsevier B.V.

    Antibiotics and antibiotic-resistant bacteria in waters associated with a hospital in Ujjain, India

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    <p>Abstract</p> <p>Background</p> <p>Concerns have been raised about the public health implications of the presence of antibiotic residues in the aquatic environment and their effect on the development of bacterial resistance. While there is information on antibiotic residue levels in hospital effluent from some other countries, information on antibiotic residue levels in effluent from Indian hospitals is not available. Also, concurrent studies on antibiotic prescription quantity in a hospital and antibiotic residue levels and resistant bacteria in the effluent of the same hospital are few. Therefore, we quantified antibiotic residues in waters associated with a hospital in India and assessed their association, if any, with quantities of antibiotic prescribed in the hospital and the susceptibility of <it>Escherichia coli </it>found in the hospital effluent.</p> <p>Methods</p> <p>This cross-sectional study was conducted in a teaching hospital outside the city of Ujjain in India. Seven antibiotics - amoxicillin, ceftriaxone, amikacin, ofloxacin, ciprofloxacin, norfloxacin and levofloxacin - were selected. Prescribed quantities were obtained from hospital records. The samples of the hospital associated water were analysed for the above mentioned antibiotics using well developed and validated liquid chromatography/tandem mass spectrometry technique after selectively isolating the analytes from the matrix using solid phase extraction. <it>Escherichia coli </it>isolates from these waters were tested for antibiotic susceptibility, by standard Kirby Bauer disc diffusion method using Clinical and Laboratory Standard Institute breakpoints.</p> <p>Results</p> <p>Ciprofloxacin was the highest prescribed antibiotic in the hospital and its residue levels in the hospital wastewater were also the highest. In samples of the municipal water supply and the groundwater, no antibiotics were detected. There was a positive correlation between the quantity of antibiotics prescribed in the hospital and antibiotic residue levels in the hospital wastewater. Wastewater samples collected in the afternoon contained both a higher number and higher levels of antibiotics compared to samples collected in the morning hours. No amikacin was found in the wastewater, but <it>E.coli </it>isolates from all wastewater samples were resistant to amikacin. Although ciprofloxacin was the most prevalent antibiotic detected in the wastewater, <it>E.coli </it>was not resistant to it.</p> <p>Conclusions</p> <p>Antibiotics are entering the aquatic environment of countries like India through hospital effluent. In-depth studies are needed to establish the correlation, if any, between the quantities of antibiotics prescribed in hospitals and the levels of antibiotic residues found in hospital effluent. Further, the effect of this on the development of bacterial resistance in the environment and its subsequent public health impact need thorough assessment.</p

    Transforming access to care for serious mental disorders in slums (the TRANSFORM Project) : rationale, design and protocol

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    This paper introduces the TRANSFORM project, which aims to improve access to mental health services for people with serious and enduring mental disorders (SMDs – psychotic disorders and severe mood disorders, often with co-occurring substance misuse) living in urban slums in Dhaka (Bangladesh) and Ibadan (Nigeria). People living in slum communities have high rates of SMDs, limited access to mental health services and conditions of chronic hardship. Help is commonly sought from faith-based and traditional healers, but people with SMDs require medical treatment, support and follow-up. This multicentre, international mental health mixed-methods research project will (a) conduct community-based ethnographic assessment using participatory methods to explore community understandings of SMDs and help-seeking; (b) explore the role of traditional and faith-based healing for SMDs, from the perspectives of people with SMDs, caregivers, community members, healers, community health workers (CHWs) and health professionals; (c) co-design, with CHWs and healers, training packages for screening, early detection and referral to mental health services; and (d) implement and evaluate the training packages for clinical and cost-effectiveness in improving access to treatment for those with SMDs. TRANSFORM will develop and test a sustainable intervention that can be integrated into existing clinical care and inform priorities for healthcare providers and policy makers

    Effect of surgical experience and spine subspecialty on the reliability of the {AO} Spine Upper Cervical Injury Classification System

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    OBJECTIVE The objective of this paper was to determine the interobserver reliability and intraobserver reproducibility of the AO Spine Upper Cervical Injury Classification System based on surgeon experience (&lt; 5 years, 5–10 years, 10–20 years, and &gt; 20 years) and surgical subspecialty (orthopedic spine surgery, neurosurgery, and "other" surgery). METHODS A total of 11,601 assessments of upper cervical spine injuries were evaluated based on the AO Spine Upper Cervical Injury Classification System. Reliability and reproducibility scores were obtained twice, with a 3-week time interval. Descriptive statistics were utilized to examine the percentage of accurately classified injuries, and Pearson’s chi-square or Fisher’s exact test was used to screen for potentially relevant differences between study participants. Kappa coefficients (κ) determined the interobserver reliability and intraobserver reproducibility. RESULTS The intraobserver reproducibility was substantial for surgeon experience level (&lt; 5 years: 0.74 vs 5–10 years: 0.69 vs 10–20 years: 0.69 vs &gt; 20 years: 0.70) and surgical subspecialty (orthopedic spine: 0.71 vs neurosurgery: 0.69 vs other: 0.68). Furthermore, the interobserver reliability was substantial for all surgical experience groups on assessment 1 (&lt; 5 years: 0.67 vs 5–10 years: 0.62 vs 10–20 years: 0.61 vs &gt; 20 years: 0.62), and only surgeons with &gt; 20 years of experience did not have substantial reliability on assessment 2 (&lt; 5 years: 0.62 vs 5–10 years: 0.61 vs 10–20 years: 0.61 vs &gt; 20 years: 0.59). Orthopedic spine surgeons and neurosurgeons had substantial intraobserver reproducibility on both assessment 1 (0.64 vs 0.63) and assessment 2 (0.62 vs 0.63), while other surgeons had moderate reliability on assessment 1 (0.43) and fair reliability on assessment 2 (0.36). CONCLUSIONS The international reliability and reproducibility scores for the AO Spine Upper Cervical Injury Classification System demonstrated substantial intraobserver reproducibility and interobserver reliability regardless of surgical experience and spine subspecialty. These results support the global application of this classification system
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