Solar Central Receiver with an Irising Aperture

Variable sun elevation, azimuthal and declination angles with the time of day, and seasons of the year respectively, give variable projected image size defects produced by field site concave mirrors on the central cavity receiver's aperture entrance. If the aperture is small, it will be inefficient for periods when the solar isolation is inclined due to spillage. However, if the aperture is large, it will be inefficient for periods when the solar isolation is normal, due to excess heat radiation and convection losses. Thus, the fixed aperture area size is a compromise between ideal sizes for different conditions. The end result is a loss of efficiency as a function of time of day and seasons of the year. This research presents an approach to maximize the interception factor on the receiver entrance, with reducing the heat losses by radiation and convection through its aperture area. A central receiver system, having a down-looking cavity with an irises aperture is being proposed for application in rich environmental solar conditions, utilized solar flux insolation throughout the day on the city of Kuwait. Solar tower focusing collector with a cavity type receiver having a fixed area aperture at the entrance is presented for comparison with the proposed technique. This collector is proved to be less efficient than the suggested design. The isiring cavity receiver with a variable area aperture provides an approximately constant efficiency regardless of the time of day or season of the year. The end result is the proposed system shows improved performance and capability. However, over the life-time of installation these advantages of the proposed system should overweigh its disadvantages of additional cost due to extra automation

Kinetic Model for Solute Diffusion in Liquid Membrane Systems

In this study, a mathematical model for the kinetics of solute transport in liquid membrane systems (LMSs) has been formulated. This model merged the mechanisms of consecutive and reversible processes with a “semi-derived” diffusion expression, resulting in equations that describe solute concentrations in the three sections (donor, acceptor and membrane). These equations have been refined into linear forms, which are satisfying in the special conditions for simplification obtaining the important kinetic constants of the process experimentally

Improving Glass Walls Thermal Resistance In Air-Conditioned Buildings

The solar radiation through an air conditioned building depends on what is called the building envelope. Building envelope consists of the surfaces that separate the inside from the building outdoors. Area, direction, and specifications of glass walls; as one of envelope surfaces; has an important impact on solar radiation. Design and construction of glass walls have significant effects on building comfort and energy consumption. This paper describes methods of improving glass walls thermal resistance in air conditioned buildings. Effect of glass wall radiation temperature on the indoor temperature distribution of building rooms is also investigated. Heat gain through various types of glass is discussed. Optimization and testing of these types are carried out theoretically and experimentally as well. A series of experiments on different types of glass with special strips is performed

Utilization of artificial intelligence approach for prediction of DLP values for abdominal CT scans: A high accuracy estimation for risk assessment

Purpose: This study aimed to evaluate Artificial Neural Network (ANN) modeling to estimate the significant dose length product (DLP) value during the abdominal CT examinations for quality assurance in a retrospective, cross-sectional study. Methods: The structure of the ANN model was designed considering various input parameters, namely patient weight, patient size, body mass index, mean CTDI volume, scanning length, kVp, mAs, exposure time per rotation, and pitch factor. The aforementioned examination details of 551 abdominal CT scans were used as retrospective data. Different types of learning algorithms such as Levenberg-Marquardt, Bayesian and Scaled-Conjugate Gradient were checked in terms of the accuracy of the training data. Results: The R-value representing the correlation coefficient for the real system and system output is given as 0.925, 0.785, and 0.854 for the Levenberg-Marquardt, Bayesian, and Scaled-Conjugate Gradient algorithms, respectively. The findings showed that the Levenberg-Marquardt algorithm comprehensively detects DLP values for abdominal CT examinations. It can be a helpful approach to simplify CT quality assurance. Conclusion: It can be concluded that outcomes of this novel artificial intelligence method can be used for high accuracy DLP estimations before the abdominal CT examinations, where the radiation-related risk factors are high or risk evaluation of multiple CT scans is needed for patients in terms of ALARA. Likewise, it can be concluded that artificial learning methods are powerful tools and can be used for different types of radiation-related risk assessments for quality assurance in diagnostic radiology. Copyright © 2022 Tekin, Almisned, Erguzel, Abuzaid, Elshami, Ene, Issa and Zakaly.The article processing charge was funded by “Dunarea de Jos” University of Galati, Romania

Utilization of artificial intelligence approach for prediction of DLP values for abdominal CT scans: A high accuracy estimation for risk assessment

PurposeThis study aimed to evaluate Artificial Neural Network (ANN) modeling to estimate the significant dose length product (DLP) value during the abdominal CT examinations for quality assurance in a retrospective, cross-sectional study.MethodsThe structure of the ANN model was designed considering various input parameters, namely patient weight, patient size, body mass index, mean CTDI volume, scanning length, kVp, mAs, exposure time per rotation, and pitch factor. The aforementioned examination details of 551 abdominal CT scans were used as retrospective data. Different types of learning algorithms such as Levenberg-Marquardt, Bayesian and Scaled-Conjugate Gradient were checked in terms of the accuracy of the training data.ResultsThe R-value representing the correlation coefficient for the real system and system output is given as 0.925, 0.785, and 0.854 for the Levenberg-Marquardt, Bayesian, and Scaled-Conjugate Gradient algorithms, respectively. The findings showed that the Levenberg-Marquardt algorithm comprehensively detects DLP values for abdominal CT examinations. It can be a helpful approach to simplify CT quality assurance.ConclusionIt can be concluded that outcomes of this novel artificial intelligence method can be used for high accuracy DLP estimations before the abdominal CT examinations, where the radiation-related risk factors are high or risk evaluation of multiple CT scans is needed for patients in terms of ALARA. Likewise, it can be concluded that artificial learning methods are powerful tools and can be used for different types of radiation-related risk assessments for quality assurance in diagnostic radiology

Safety and efficacy of single dose versus multiple doses of AmBisome for treatment of visceral leishmaniasis in eastern Africa: a randomised trial.

BACKGROUND: Anti-leishmanial drug regimens that include a single dose AmBisome could be suitable for eastern African patients with symptomatic visceral leishmaniasis (VL) but the appropriate single dose is unknown. METHODOLOGY: A multi-centre, open-label, non-inferiority, randomized controlled trial with an adaptive design, was conducted to compare the efficacy and safety of a single dose and multiple doses of AmBisome for the treatment of VL in eastern Africa. The primary efficacy endpoint was definitive cure (DC) at 6 months. Symptomatic patients with parasitologically-confirmed, non-severe VL, received a single dose of AmBisome 7.5 mg/kg body weight or multiple doses, 7 times 3 mg/kg on days 1-5, 14, and 21. If interim analyses, evaluated 30 days after the start of treatment following 40 or 80 patients, showed the single dose gave significantly poorer parasite clearance than multiple doses at the 5% significance level, the single dose was increased by 2·5 mg/kg. In a sub-set of patients, parasite clearance was measured by quantitative reverse transcriptase (qRT) PCR. PRINCIPAL FINDINGS: The trial was terminated after the third interim analysis because of low efficacy of both regimens. Based on the intention-to-treat population, DC was 85% (95%CI 73-93%), 40% (95%CI 19-64%), and 58% (95%CI 41-73%) in patients treated with multiple doses (n = 63), and single doses of 7·5 (n = 21) or 10 mg/kg (n = 40), respectively. qRT-PCR suggested superior parasite clearance with multiple doses as early as day 3. Safety data accorded with the drug label. CONCLUSIONS: The tested AmBisome regimens would not be suitable for VL treatment across eastern Africa. An optimal single dose regimen was not identified. TRIALS REGISTRATION: www.clinicaltrials.govNCT00832208

The PROVENT-C19 registry: A study protocol for international multicenter SIAARTI registry on the use of prone positioning in mechanically ventilated patients with COVID-19 ARDS

Background The worldwide use of prone position (PP) for invasively ventilated patients with COVID-19 is progressively increasing from the first pandemic wave in everyday clinical practice. Among the suggested treatments for the management of ARDS patients, PP was recommended in the Surviving Sepsis Campaign COVID-19 guidelines as an adjuvant therapy for improving ventilation. In patients with severe classical ARDS, some authors reported that early application of prolonged PP sessions significantly decreases 28-day and 90-day mortality. Methods and analysis Since January 2021, the COVID19 Veneto ICU Network research group has developed and implemented nationally and internationally the "PROVENT-C19 Registry", endorsed by the Italian Society of Anesthesia Analgesia Resuscitation and Intensive Care. . .'(SIAARTI). The PROVENT-C19 Registry wishes to describe 1. The real clinical practice on the use of PP in COVID-19 patients during the pandemic at a National and International level; and 2. Potential baseline and clinical characteristics that identify subpopulations of invasively ventilated patients with COVID-19 that may improve daily from PP therapy. This web-based registry will provide relevant information on how the database research tools may improve our daily clinical practice. Conclusions This multicenter, prospective registry is the first to identify and characterize the role of PP on clinical outcome in COVID-19 patients. In recent years, data emerging from large registries have been increasingly used to provide real-world evidence on the effectiveness, quality, and safety of a clinical intervention. Indeed observation-based registries could be effective tools aimed at identifying specific clusters of patients within a large study population with widely heterogeneous clinical characteristics. Copyright

The evolving SARS-CoV-2 epidemic in Africa: insights from rapidly expanding genomic surveillance

Investment in SARS-CoV-2 sequencing in Africa over the past year has led to a major increase in the number of sequences generated, now exceeding 100,000 genomes, used to track the pandemic on the continent. Our results show an increase in the number of African countries able to sequence domestically, and highlight that local sequencing enables faster turnaround time and more regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and shed light on the distinct dispersal dynamics of Variants of Concern, particularly Alpha, Beta, Delta, and Omicron, on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve, while the continent faces many emerging and re-emerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Diabetes mellitus and obesity among South Asians with ischemic stroke across three countries

Background: Diabetes mellitus and central obesity are more common among South Asian populations than among White British people. This study explores the differences in diabetes and obesity in South Asians with stroke living in the United Kingdom, India, and Qatar compared with White British stroke patients. Methods: The study included the UK, Indian, and Qatari arms of the ongoing large Bio-Repository of DNA in Stroke (BRAINS) international prospective hospital-based study for South Asian stroke. BRAINS includes 4580 South Asian and White British recruits from UK, Indian, and Qatar sites with first-ever ischemic stroke. Results: The study population comprises 1751 White British (WB) UK residents, 1165 British South Asians (BSA), 1096 South Asians in India (ISA), and 568 South Asians in Qatar (QSA). ISA, BSA, and QSA South Asians suffered from higher prevalence of diabetes compared with WB by 14.5% (ISA: 95% confidence interval (CI) = 18.6–33.0, p < 0.001), 31.7% (BSA: 95% CI = 35.1–50.2, p < 0.001), and 32.7% (QSA: 95% CI = 28.1–37.3, p < 0.001), respectively. Although WB had the highest prevalence of body mass index (BMI) above 27 kg/m2 compared with South Asian patients (37% vs 21%, p < 0.001), South Asian patients had a higher waist circumference than WB (94.8 cm vs 90.8 cm, p < 0.001). Adjusting for traditional stroke risk factors, ISA, BSA, and QSA continued to display an increased risk of diabetes compared with WB by 3.28 (95% CI: 2.53–4.25, p < 0.001), 3.61 (95% CI: 2.90–4.51, p < 0.001), and 5.24 (95% CI: 3.93–7.00, p < 0.001), respectively. Conclusion: South Asian ischemic stroke patients living in Britain and Qatar have a near 3.5-fold risk of diabetes compared with White British stroke patients. Their body composition may partly help explain that increased risk. These findings have important implications for public health policymakers in nations with large South Asian populations