A New Model for the Analysis of Performance in Evacuated Tube Solar Collectors

Solar collectors can provide a useful response to the heat demand in buildings, such as heating of domestic water and spaces. Among the different types of solar collectors, the evacuated tube ones can better display their features when the temperature difference between operating fluid and ambient air is high, which are the typical operating conditions during space heating of buildings. Beside the heating application, there is also need for addressing the increasing energy consumption due to the summer air conditioning. Solar cooling can be an interesting opportunity, because the cooling demand matches the period with the higher solar radiation availability. Also in this application the evacuated collectors are an adequate type, due to the temperature level of the heat required as an input to the absorption machines. Therefore, accurate modeling and simulation of this type of collectors is highly recommended to fully assess the performance of the collectors already available in the market and propose improved designs, for example with higher concentration ratio, to get more benefits particularly at higher levels of temperature. This paper reports a new model for the performance analysis of evacuated tube solar collectors. The analyzed collectors are truncated CPC (compound parabolic collectors). An original software is developed under MATLAB environment for the simulation purposes. A novel numerical procedure is implemented to obtain the solution for the nonlinear set of equations representing the mathematical model. The length of the tube is divided into a specified number of segments. The analysis is performed for each segment along the tube length in order to obtain the variation of the different parameters. The model analyzes separately the optics and the heat transfer in the evacuated tubes and this approach allows to extend the analysis to new configurations. The model can simulate the efficiency curve under steady state conditions, according to the standard EN 12975-2 (EN 12975-2. Thermal solar systems and components - solar collectors - part 2: test methods. Brussels: CEN; 2006), but it is also able to describe the performance during the day with a quasi-dynamic approach. A comparison with experimental data shows the accuracy of the model. The results will provide a comprehensive characterization of the performance of evacuated tube collectors, discussing modeling and experimental data of efficiency and heat production at different levels of temperature. Particular attention will be paid to the applications of heating and cooling of buildings, industrial process heat generation and district heating

Partial synthetic PPARƳ derivative ameliorates aorta injury in experimental diabetic rats mediated by activation of miR-126-5p Pi3k/AKT/PDK 1/mTOR expression

Type 2 diabetes mellitus (T2D) is a world wild health care issue marked by insulin resistance, a risk factor for the metabolic disorder that exaggerates endothelial dysfunction, increasing the risk of cardiovascular complications. Peroxisome proliferator-activated receptor PPAR) agonists have therapeutically mitigated hyperlipidemia and hyperglycemia in T2D patients. Therefore, we aimed to experimentally investigate the efficacy of newly designed synthetic PPARα/Ƴ partial agonists on a High-Fat Diet (HFD)/streptozotocin (STZ)-induced T2D. Female Wistar rats (200 ± 25 g body weight) were divided into four groups. The experimental groups were fed the HFD for three consecutive weeks before STZ injection (45 mg/kg/i.p) to induce T2D. Standard reference PPARƳ agonist pioglitazone and the partial synthetic PPARƳ (PIO; 20 mg/kg/BW, orally) were administered orally for 2 weeks after 72 h of STZ injection. The aorta tissue was isolated for biological ELISA, qRT-PCR, and Western blotting investigations for vascular inflammatory endothelial mediators endothelin-1 (ET-1), intracellular adhesion molecule 1 (ICAM-1), E-selectin, and anti-inflammatory vasoactive intestinal polypeptide (VIP), as well as microRNA126-5p and p-AKT/p-Pi3k/p-PDK-1/p-mTOR, endothelial Nitric Oxide Synthase (eNOS) immunohistochemical staining all are coupled with and histopathological examination. Our results revealed that HFD/STZ-induced T2D increased fasting blood glucose, ET-1, ICAM-1, E-selectin, and VIP levels, while decreasing the expression of both microRNA126-5p and p-AKT/p-Pi3k/p-PDK-1/p-mTOR phosphorylation. In contrast, the partial synthetic PPARƳ derivative evidenced a vascular alteration significantly more than reference PIO via decreasing (ET-1), ICAM-1, E-selectin, and VIP, along with increased expression of microRNA126-5p and p-AKT/p-Pi3k/p-PDK-1/p-mTOR. In conclusion, the partial synthetic PPARƳ derivative significantly affected HFD/STZ-induced T2D with vascular complications in the rat aorta

<i>Garcinia cambogia</i> phenolics as potent anti-COVID-19 agents:phytochemical profiling, biological activities, and molecular docking

COVID-19 is a disease caused by the coronavirus SARS-CoV-2 and became a pandemic in a critically short time. Phenolic secondary metabolites attracted much attention from the pharmaceutical industries for their easily accessible natural sources and proven antiviral activity. In our mission, a metabolomics study of the Garcinia cambogia Roxb. fruit rind was performed using LC-HRESIMS to investigate its chemical profile, especially the polar aspects, followed by a detailed phytochemical analysis, which led to the isolation of eight known compounds. Using spectrometric techniques, the isolated compounds were identified as quercetin, amentoflavone, vitexin, rutin, naringin, catechin, p-coumaric, and gallic acids. The antiviral activities of the isolated compounds were investigated using two assays; the 3CL-Mpro enzyme showed that naringin had a potent effect with IC50 16.62 &mu;g/mL, followed by catechin and gallic acid (IC50 26.2, 30.35 &mu;g/mL, respectively), while the direct antiviral inhibition effect of naringin confirmed the potency with an EC50 of 0.0169 &mu;M. To show the molecular interaction, in situ molecular docking was carried out using a COVID-19 protease enzyme. Both biological effects and docking studies showed the hydrophobic interactions with Gln 189 or Glu 166, per the predicated binding pose of the isolated naringin

Nature as a treasure trove of potential anti-SARS-CoV drug leads:a structural/mechanistic rationale

The novel Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 is a potential factor for fatal illness and a tremendous concern for global public health. The COVID-19 pandemic has entered a dangerous new phase. In the context of drug discovery, the structurally-unique and chemically-diverse natural products have been valuable sources for drug leads. In this review, we report for potential candidates derived from natural sources with well-reported in vitro efficacy against SARS-CoV during the last decade. Additionally, a library of 496 phenolic metabolites was subjected to a computer-aided virtual screening against the active site of the recently reported SARS-CoV Main protease (M(pro)). Analysis of physicochemical properties of these natural products has been carried out and presented for all the tested phenolic metabolites. Only three of the top candidates, viz. acetylglucopetunidin (31), isoxanthohumol (32) and ellagic acid (33), which are widely available in many edible fruits, obey both Lipinski's and Veber's rules of drug-likeness and thus possess high degrees of predicted bioavailability. These natural products are suggested as potential drug candidates for the development of anti-SARS-CoV-2 therapeutics in the near future

Dissemination of multiple carbapenem-resistant clones of Acinetobacter baumannii in the Eastern District of Saudi Arabia

It has previously been shown that carbapenem-resistant Acinetobacter baumannii are frequently detected in Saudi Arabia. The present study aimed to identify the epidemiology and distribution of antibiotic resistance determinants in these bacteria. A total of 83 A. baumannii isolates were typed by pulsed-field gel electrophoresis (PFGE), and screened by PCR for carbapenemase genes and insertion sequences. Antibiotic sensitivity to imipenem, meropenem, tigecycline, and colistin were determined. Eight different PFGE groups were identified, and were spread across multiple hospitals. Many of the PFGE groups contained isolates belonging to World-wide clone 2. Carbapenem resistance or intermediate resistance was detected in 69% of isolates. The blaVIM gene was detected in 94% of isolates, while blaOXA–23–like genes were detected in 58%. The data demonstrate the co-existence and wide distribution of a number of clones of carbapenem-resistant A. baumannii carrying multiple carbapenem-resistance determinants within hospitals in the Eastern Region of Saudi Arabia

Thermal Performance Evaluation of Common Exterior Residential Wall Types in Egypt

The demand for energy-efficient housing is on the rise in Egypt. The information about the individual materials used in the construction of typical residential wall assemblies are known in the literature. However, data from lab tests to validate the performance for whole composite walls are limited. Three typical wall types were constructed and tested utilizing a standard experimental evaluation procedure based on thermal convection loads. A research framework combining the validated thermal performance data from the experimental test and the simulated data was developed. The experimental tests were performed utilizing a state-of-the-art guarded hotbox apparatus and following the guidelines of the ASTM C1363-11 standard. The solar radiation load was taken into account in the calculations according to the standard, and the error estimation and uncertainty analysis for the experimental tests are reported. The results of the experimental testing are described and a recommendation of the best wall type is noted. The output of this research will help to initiate a material database of the thermal performance of typical residential wall types used in Egypt that have been validated in the lab. This will be useful for the building industry as a whole to understand the performance of the materials in composite assemblies and their impact on energy efficiency

Thermal performance evaluation of common exterior residential wall types in Egypt

© 2019 by the authors. The demand for energy-efficient housing is on the rise in Egypt. The information about the individual materials used in the construction of typical residential wall assemblies are known in the literature. However, data from lab tests to validate the performance for whole composite walls are limited. Three typical wall types were constructed and tested utilizing a standard experimental evaluation procedure based on thermal convection loads. A research framework combining the validated thermal performance data from the experimental test and the simulated data was developed. The experimental tests were performed utilizing a state-of-the-art guarded hotbox apparatus and following the guidelines of the ASTM C1363-11 standard. The solar radiation load was taken into account in the calculations according to the standard, and the error estimation and uncertainty analysis for the experimental tests are reported. The results of the experimental testing are described and a recommendation of the best wall type is noted. The output of this research will help to initiate a material database of the thermal performance of typical residential wall types used in Egypt that have been validated in the lab. This will be useful for the building industry as a whole to understand the performance of the materials in composite assemblies and their impact on energy efficiency

Diode laser in management of loss of taste sensation in patients with post-COVID syndrome: a randomized clinical trial

Abstract Objective Loss of taste (ageusia) is a symptom observed following recovery from COVID-19 infection. The loss of taste and smell sensation may negatively affect patients’ quality of life (QoL). The present study aimed to evaluate the effectiveness of the Diode Laser in managing loss of taste sensation in patients with post-COVID syndrome versus the placebo. Material and method The study sample was 36 patients who complained of persistent loss of taste sensation following COVID-19. The patients were randomly assigned to one of the two groups according to the received treatment: Group I (laser treatment) and Group II (light treatment), with each patient receiving a diode laser treatment or placebo from the same operator. Taste sensation was subjectively measured after treatment for four weeks. Results The results demonstrated a significant difference between both groups regarding taste restoration after one month (p = 0.041), with Group II having a significantly higher percentage of cases 7 (38.9%) with partial taste restoration. In contrast, a significantly higher proportion of Group I 17 cases (94.4%) had complete taste restoration (p < 0.001). Conclusion The present study concluded that using a Diode laser 810 nm aided in a more rapid recovery from loss of taste dysfunction

Metabolomic profiling, biological evaluation of <i>Aspergillus awamori</i>, the river Nile-derived fungus using epigenetic and OSMAC approaches

LC-HRMS-based metabolomics approach was applied to the river Nile-derived fungus Aspergillus awamori after its fermentation on four different media and using four epigenetic modifiers as elicitors. Thereafter, a comprehensive multivariate statistical analysis such as PCA, PLS-DA and OPLS-DA were employed to explain the generated metabolomic data (1587 features). PCA showed that the fungus displayed a unique chemical profile in each medium or elicitor. Additionally, PLS-DA results revealed the upregulated metabolites under each of these conditions. Results indicated that both rice and malt dextrose agar were recognized as the best media in terms of secondary metabolites diversity and showed better profiles than the four applied epigenetic modifiers, of which nicotinamide was the best secondary metabolite elicitor. Testing the antibacterial and cytotoxic effects of all A. awamori-derived extracts revealed that using epigenetic modifiers can induce antimicrobial metabolites against S. aureus and E. coli, whereas using rice, malt dextrose or nicotinamide can induce groups of cytotoxic metabolites. OPLS-DA results assisted in the putative identification of the induced metabolites that could be responsible for these observed inhibitory activities. This study highlighted how powerful the OSMAC approach in maximizing of the chemical diversity of a single organism. Furthermore, it revealed the power of metabolomics in tracing, profiling and categorizing such chemical diversity and even targeting the possible bioactive candidates which require further scaling up studies in the future