210 research outputs found
Thermal performance enhancement of evacuated tube solar collector using MWCNT, Al2O3, and hybrid MWCNT/ Al2O3nanofluids
Nanofluids have numerous applications in heat transference procedures due to their exceptional thermal characteristics. The most desirable parameter to enhance the solar collector's performance is the enhancement of the convective heat transfer coefficient between the working fluid tubes and the absorber. As a result, nanofluids have gained prominence as working fluids in solar thermal systems. The trendsetting review reveals that mostly the nanofluids in solar collectors are based on water employing nanoparticles of Al2O3, TiO2, SiO2, and CuO. Besides, nanoparticle concentration is a challenging factor in using nanofluids. In this research, under controlled conditions, the working fluids multi-wall carbon nanotube, Aluminum Oxide, and hybrid MWCNT/Al2O3 50:50% were experimentally examined for the thermal efficiency enhancement of the evacuated tube solar collector. For each type of nanofluid, four volume concentration percentages (0.5%, 0.025%, 0.01%, and 0.005%) were examined along with three distinct mass flow rates. According to the findings, using hybrid MWCNT/Al2O3 50:50% delivers an efficiency boost of about 20% overusing Al2O3, as was previously reported. Finally, it was found that the utilization of 0.5% MWCNT/water nanofluid at 3.5 L/m can enhance the ETSC's energy and exergy efficiency to reach 73.5% and 51% respectively while reaching approximately 60% and 44% for AL2O3, and 69% and 38% for hybrid MWCNT/Al2O3 (50:50%) under the same test conditions
Petrography, geochemistry and K-Ar dating of some metagabbros from the Central Easern Desert, Egypt
Natural immunity to influenza virus in humans following 2009 pandemic H1N1 influenza
Influenza is a highly contagious and acute respiratory infection caused by influenza virus in the mucosa of the respiratory tract. Both seasonal and pandemic influenza continue to cause substantial morbidity and mortality in humans. The 2009 pandemic H1N1 (pH1N1) influenza and the potential of a highly pathogenic avian H5N1 (aH5N1) pandemic highlighted the need for effective preventative strategies. Understanding the development of natural immunity following the pH1N1 pandemic may provide important information on host protective immunity in humans, which could inform future more effective vaccination strategies against influenza. In this thesis, naturally developed mucosal immunity to 2009 pH1N1 virus was studied in children and adults using cells derived from human nasal-associated lymphoid tissue (NALT). Firstly, the frequency of HA-specific memory B cells in human NALT to pH1N1 virus and their ability to produce cross-reactive antibodies were studied. Patients who had serological evidence of previous exposure to pH1N1 virus developed large numbers of IgG memory B cells in NALT that produce crossreactive neutralizing antibodies against a number of influenza subtypes upon pH1N1 virus antigen stimulation. The presence of such memory B cells in human NALT appears to have primed the host for cross-reactive mucosal memory response against other H1N1 and the highly pathogenic aH5N1 virus strains. These findings may have important implications in future vaccination strategies against influenza. Secondly, serum specific anti-pH1N1 HA IgG antibodies were analysed using ELISA. HA-specific antibody levels to pH1N1 in adults were significantly higher than that of children. The results may suggest that adults had been exposed to more cross-reactive influenza viruses than children, and developed more cross-reactive memory responses against some influenza viruses than in children. Significantly higher HA-specific IgG antibody titres to pH1N1 HA (measured using ELISA) were found in subjects who had HAI titresâ„40 than in those with HAI antibody titr
Guidelines for data collection on energy performance of higher-education buildings in Egypt: a case study
Reliable energy analysis of buildings relies heavily on high-quality data leading to proper indicators. Previous studies have highlighted the importance of data quality in analyzing energy usage in residential and non-residential buildings in order to transform declarations to actions, optimise energy efficiency policies and monitor progress and failures in countries. Collected data must adhere to national and international standards for energy performance in buildings. This study aims to provide practical guidelines for effectively collecting and preparing data suitable for evaluating energy performance in Egyptian higher-education (HE) buildings. The guidelines are developed based on a comprehensive case study, considering data availability in typical educational facilities. Architectural and civil engineering drawings, construction specifications, and occupancy details are accessible. However, actual monthly electrical and natural gas consumption data for individual buildings are lacking. To address this, the study proposes the creation of detailed datasheets for each building, encompassing all energy sources and their electrical and power specifications, such as equipment, machinery, and HVAC systems. These datasheets were utilized to calculate energy consumption and energy usage indicators (EUI). The findings demonstrate that the datasheets enable adequate assessment of energy usage in various spaces within educational buildings, including staff rooms, lecture halls, and laboratories. This facilitates the identification of areas in need of targeted energy efficiency improvements. Notably, the study reveals that electricity consumption in the Faculty of Engineering building is significantly influenced by PCs, laboratories, lighting, and air conditioning
Accelerated cooling of steel rebars establishment of technological and design parameters of the cooling unit by modelling and experimentation
The aim of this work is to develop a computer mathematical model that could be used to predict the design parameters of an accelerated cooling unit. These parameters include length and diameter of cooling tube, size, number and type of nozzles and amount of water needed. Such units are encorporated at the end of or before the last rolling mill of re-inforcing bars for the production of high strength steel re-bars. The production of high strength steel rebars from ordinary 0.2% C - 0.8% Mn by thermo-mechanical treating has been widely employed recently. The control of the cooling rates through the water flow (cross sectional area of tube and amount of water) and cooling time (length of unit which varies according to the rolling speed) affects the process greatly. The bars that leave the stand at about1000°C, are cooled in a long tube with high pressure water. The outer surface cools to about 200-400°Cforming a martensftic layer, while the inner areas remain hot (1000°C). Then both surface and core temperatures equalise at a certain temperature which greatly affects the strength of the cooled rebars. It is of great importance to be able to predict this temperature and previously mentioned design parameters to be able to build the cooling unit required to achieve certain strength levels. The results of the model have been used to develop a cooling unit at El-Ahlya National Company. The performance of the unit was verified experimentally, where several experiments were carried out for different bar diameters, in the range 12-16 mm, and various cooling conditions leading to different bar equalising temperatures.Strength values in the range from 430 to 1500 MPa were obtained by changing cooling conditions. The obtained mechanical properties after cooling were compared with the predicted equalising temperatures. Also, the microstructures of the cooled bars were compared with those predicted by the cooling curves obtained from the mathematical model results. The results obtained from the model predicted to great proximfty the experimentally obtained results
Oral Delivery of Psoralidin by Mucoadhesive Surface-Modified Bilosomes Showed Boosted Apoptotic and Necrotic Effects against Breast and Lung Cancer Cells
© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).This study aims to design and optimize chitosan-coated bilosomal formulations loaded with psoralidin (Ps-CS/BLs) with improved physicochemical properties, oral bioavailability, and boosted apoptotic and necrotic effects. In this regard, uncoated bilosomes loaded with Ps (Ps/BLs) were nanoformulated using the thin-film hydration technique using different molar ratios of phosphatidylcholine (PC), cholesterol (Ch), Span 60 (S60), and sodium deoxycholate (SDC) (1:0.4:0.2:0.125, 1:0.4:0.2:0.25, and 1:0.4:0.2:0.5, respectively). The best-optimized formulation with respect to size, PDI, zeta potential, and EE% was selected and then coated with chitosan at two different concentrations (0.125 and 0.25 w/v%), forming Ps-CS/BLs. The optimized Ps/BLs and Ps-CS/BLs showed a spherical shape and relatively homogenous size with negligible apparent agglomerations. Additionally, it was demonstrated that coating Ps/BLs with chitosan has significantly increased the particle size from 123.16 ± 6.90 in the case of Ps/BLs to 183.90 ± 15.93 nm in the case of Ps-CS/BLs. In addition, Ps-CS/BLs exhibited higher zeta potential (+30.78 ± 1.44 mV) as compared to Ps/BLs (â18.59 ± 2.13 mV). Furthermore, Ps-CS/BL showed enhanced entrapment efficiency (EE%) of 92.15 ± 7.20% as compared to Ps/BLs (68.90 ± 5.95%). Moreover, Ps-CS/BLs exhibited a more sustained release behavior of Ps compared to Ps/BLs over 48 h, and both formulations were best obeying the Higuchi diffusion model. More importantly, Ps-CS/BLs displayed the highest mucoadhesive efficiency% (74.89 ± 3.5%) as compared to Ps/BLs (26.78 ± 2.9%), indicating the ability of the designed nanoformulation to improve oral bioavailability and extend the residence time inside the gastrointestinal tract upon oral administration. Moreover, upon evaluating the apoptotic and necrotic effects of free Ps and Ps-CS/BLs on human breast cancer cell lines (MCF-7) and human lung adenocarcinoma cell lines (A549), there was a dramatic increase in the percentages of the apoptotic and necrotic cell compared to the control and free Ps. Our findings suggest the possible oral use of Ps-CS/BLs in hampering breast and lung cancers.Peer reviewe
Preparation, optimization, and in vitro simulated inhalation delivery of carvedilol nanoparticles loaded on a coarse carrier intended for pulmonary administration
Can Unconventional Immunomodulatory Agents Help Alleviate COVID-19 Symptoms and Severity?
Severe acute respiratory syndrome coronavirus 2 (SARS coronavirus 2, or SARS-CoV-2) is the cause of the respiratory infection known as COVID-19. From an immunopathological standpoint, coronaviruses such as SARS-CoV-2 induce increased levels of a variety of T-helper 1 (Th1) and inflammatory cytokines and chemokines, including interleukin-1 (IL-1), IL-6, CCL2 protein, and CXCL10 protein. In the absence of proven antiviral agents or an effective vaccine, substances with immunomodulatory activity may be able to inhibit inflammatory and Th1 cytokines and/or yield an anti-inflammatory and/or Th2 immune response to counteract COVID-19 symptoms and severity. This report briefly describes the following four unconventional but commercially accessible immunomodulatory agents that can be employed in clinical trials to evaluate their effectiveness at alleviating disease symptoms and severity: low-dose oral interferon alpha, microdose DNA, low-dose thimerosal, and phytocannabinoids
Association of Viral Load in SARS-CoV-2 Patients With Age and Gender
Background: The coronavirus disease 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is a global public health emergency. Age and sex are two important factors associated with risks and outcomes of various diseases. COVID-19 morbidity also seems to be affected by patient age and sex. It has been found that older age groups have more severe COVID-19 symptoms and higher fatality rates while children tend to have lower prevalence and milder symptoms than adults. Methods: The study reviewed electronic medical records of COVID-19 patients from Madinah city, Saudi Arabia. The study included all cases who tested positive (n = 3,006) between March 20 and May 22, 2020. Data were obtained from the Health Electronic Surveillance Network (HESN) database. Results: Approximately 80% of the study sample were males and half were in the 30-40-year-old age group. The Ct value of the whole sample ranged from 15.08 to 35, with a mean of 27.44 (SD: 5.23; 95% C.I. = 27.25-27.66). The means of Ct values varied between age groups from 27.05 to 27.82. Analysis of the mean differences between age groups using one-way ANOVA indicated no statistically significant difference among the groups (F6,2999 = 1.63; p-value = 0.135). A comparison of mean Ct values of males (n = 2,422) and females (n = 584) revealed that males had a statistically significant higher mean Ct value (27.61 ± 5.20) than females (26.72 ± 5.31). The difference between the means of the two groups was -0.89 (95% C.I. = -1.36 to -0.42; t-test -3.71; df = 3,004; p-value Conclusion: The study found no statistically significant difference in viral loads between age groups. It showed that females had a higher SARS-CoV-2 viral load compared to males. The findings have implications for preventive strategies. Further studies are needed to correlate viral load with clinical symptoms and outcomes
Infection with 2009 H1N1 influenza virus primes for immunological memory in human nose-associated lymphoid tissue, offering cross-reactive immunity to H1N1 and avian H5N1 viruses
Influenza is a highly contagious mucosal infection in the respiratory tract. 2009 pandemic H1N1 (pH1N1) virus infection resulted in substantial morbidity and mortality in humans. Little is known on whether immunological memory develops following pH1N1 infection and whether it provides protection against other virus subtypes. Enzyme-linked immunosorbent spot assay was used to analyze hemagglutinin (HA)-specific memory B cell responses after virus antigen stimulation in nasal-associated lymphoid tissues (NALT) from children and adults. Individuals with serological evidence of previous exposure to pH1N1 showed significant cross-reactive HA-specific memory B responses to pH1N1, seasonal H1N1(sH1N1) and avian H5N1(aH5N1) viruses upon pH1N1 virus stimulation. pH1N1 virus antigen elicited stronger cross-reactive memory B cell responses than sH1N1 virus. Intriguingly, aH5N1 virus also activated cross-reactive memory responses to sH1N1 and pH1N1 HAs in those who had previous pH1N1 exposure, and that correlated well with the memory response stimulated by pH1N1 virus antigen. These memory B cell responses resulted in cross-reactive neutralizing antibodies against sH1N1, 1918 H1N1 and aH5N1viruses. 2009 pH1N1 infection appeared to have primed human host with B cell memory in NALT that offers cross-protective mucosal immunity against not only H1N1 but also aH5N1 viruses. These findings may have important implications to future vaccination strategies against influenza. It will be important to induce and/or enhance such cross-protective mucosal memory B cells
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