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209 result(s) for "Orabi, M"
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Radon indoor concentration time-variation model
The time variation of radon indoor concentration is studied using a semi empirical model . The mass balance formula for radon indoors is applied to put a descriptive equation that considers every source of the radon . The resultant equation is solved analytically with imposing a number of approximate forms that are justified by their empirical background. The model ’s parameters are fitted to some experimental radon indoor concentration data to estimate a set of descriptive figures for radon entry to indoors from the wall s and ground of a room . The current study focuses on applying the model on a short period of time . The model is successful and provides a good description for the data, with further prediction of the possibility of having an unrecognized source of radon .
Calculating the indoor radon flux from construction materials and soil
A theoretical method is used to calculate the radon exhalation and flux from the walls of a room and the soil to the living space in the room. The calculations are based on the Fick’s laws to describe the radon diffusion through the walls and in the soil. In both cases, the diffusion is considered as one-dimension along the direction to the inside of the room. Under some conditions, the three-dimensional diffusion has to be taken into account. A comparison between the one- and three-dimensional descriptions is discussed, and hence the radon areal release rate from a wall and that from a construction material sample are formulated and related. Consequent indoor radon concentrations and inhalation doses are represented. The effect of the radon release from the construction materials on calculating the gamma dose rate in a room is studied.
Modeling the indoor gamma-radiation dose: A review of refinements and application
. A theoretical model to estimate the gamma-radiation dose rates inside a room is reviewed, refined and applied. The scheme of the model is based on the relative effects of the different room elements that control the amount of radiation. The relative dose rates are simulated by the MCNP5 software. The studied gamma radiation is the one due to the two radioactive decay series 238 U and 232 Th, and the radionuclide 40 K. The affecting elements considered are the widths of the parts of the room, the density of the construction material, the lengths and heights of the different parts of the room, radiation from neighboring rooms, the uncertainty in the equilibrium of the 238 U series. The effects of the existence of a gap inside some of the walls and the existence of partial walls, windows and doors are also studied. The model is applied through an example that includes all the enrolled factors.
Multi-layer description model for radon concentration in soil
. A theoretical model is proposed to describe some experimental data for radon concentration in soil. The data shows a non-monotonic increase of the radon concentration with the soil depth. The model is based on the general transport equation that includes both diffusion and advection. A multi-layer soil configuration is assumed. Two challenges are faced. The first is that the exact solution of the transport equation is cumbersome to deal with for describing soils with more than two layers. The second is that some approximate solutions may lead to discontinuity between the different layers. In this study an efficient mathematical formulation is suggested that successfully reaches an approximate form which can cope with the two challenges. This formula is much simpler than the exact one, and can easily be applied to include many layers with smooth transition from one layer to the next. The model gives a good fitting with the experimental data and gives important characteristics of radon distribution and transport in soils that require a multi-layer description.
In vitro digestive system simulation and anticancer activity of soymilk fermented by probiotics and synbiotics immobilised on agro-industrial residues
In this study, a variety of probiotic strains, including Lactiplantibacillus plantarum, Lacticaseibacillus casei, Lactobacillus acidophilus, Streptococcus thermophilus, Bifidobacterium longum, Limosilactobacillus reuteri, Lactobacillus delbrueckii subsp. bulgaricus, Lacticaseibacillus rhamnosus, and Bifidobacterium bifidum , were utilized for soymilk fermentation both as free cells and as synbiotics on agro-industrial residuals such as okara, whey protein, banana peels, apple pomace, sugarcane bagasse, orange peels, and lemon peels. Among these, Lacticaseibacillus rhamnosus emerged as the most significant strain for soymilk fermentation, exhibiting a viability of 10.47 log cfu/mL, a pH of 4.41, total acidity of 1.12%, and organic acid contents (lactic and acetic acid) of 11.20 and 7.50 g/L, respectively. As a synbiotic Lacticaseibacillus rhamnosus immobilised on okara, showed even more impressive results, with a viability of 12.98 log cfu/mL, a pH of 4.31, total acidity of 1.27%, and organic acid contents of 13.90 and 9.30 g/L, respectively. Over a 12-h fermentation period, cell viability values increased by 10.47-fold in free cells and 11.19-fold in synbiotics. Synbiotic supplementation of fermented soymilk proved more beneficial than free cells in terms of viability, acidity, and organic acid content. Furthermore, when synbiotic fermented soymilk was freeze-dried to simulate the digestive system in vitro, synbiotics and freeze-dried cells demonstrated superior gastrointestinal tract survival compared to free cells. Both the probiotic bacteria and the synbiotics exhibited cytotoxicity against colon and liver cancer cell lines, with half-maximal inhibitory concentrations ranging from 41.96 to 61.52 μL/well.
Caring for carers: A virtual psychosocial supervision intervention to improve the quality and sustainability of mental health and psychosocial support in humanitarian contexts
IntroductionMental health and psychosocial support (MHPSS) staff in humanitarian settings have limited access to clinical supervision and are at high risk of experiencing burnout. We previously piloted an online, peer-supervision program for MHPSS professionals working with displaced Rohingya (Bangladesh) and Syrian (Turkey and Northwest Syria) communities. Pilot evaluations demonstrated that online, peer-supervision is feasible, low-cost, and acceptable to MHPSS practitioners in humanitarian settings.ObjectivesThis project will determine the impact of online supervision on i) the wellbeing and burnout levels of local MHPSS practitioners, and ii) practitioner technical skills to improve beneficiary perceived service satisfaction, acceptability, and appropriateness.MethodsMHPSS practitioners in two contexts (Bangladesh and Turkey/Northwest Syria) will participate in 90-minute group-based online supervision, fortnightly for six months. Sessions will be run on zoom and will be co-facilitated by MHPSS practitioners and in-country research assistants. A quasi-experimental multiple-baseline design will enable a quantitative comparison of practitioner and beneficiary outcomes between control periods (12-months) and the intervention. Outcomes to be assessed include the Kessler-6, Harvard Trauma Questionnaire and Copenhagen Burnout Inventory and Client Satisfaction Questionnaire-8.ResultsA total of 80 MHPSS practitioners will complete 24 monthly online assessments from May 2022. Concurrently, 1920 people receiving MHPSS services will be randomly selected for post-session interviews (24 per practitioner).ConclusionsThis study will determine the impact of an online, peer-supervision program for MHPSS practitioners in humanitarian settings. Results from the baseline assessments, pilot evaluation, and theory of change model will be presented.DisclosureNo significant relationships.
Ajuga orientalis L. Extract as a Green Corrosion Inhibitor of Aluminum in an Acidic Solution: An Experimental and DFT Study
The inhibitory effect of A. orientalis L. extract (AO) on aluminum corrosion in a 1.0 M HCl solution was investigated utilizing weight loss, electrochemical polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The results show that AO is a potent inhibitor in an acidic environment, and that the inhibition potency increases with concentration. Temperature investigations showed that, in an acidic medium, the efficiency decreased, increased, and then decreased as the temperature rose. Adsorption isotherms from Freundlich, Temkin, El Awady, and Redlich–Peterson (R-P) approximated the inhibitor’s adsorption properties. For the inhibitory behavior, a physical and chemical adsorption mechanism is proposed. The adsorption process’s thermodynamic parameters (Ea, ΔH*, and ΔS*) were determined and explained. The inhibitor, AO, was identified as a mixed-type (anodic and cathodic) inhibitor based on polarization studies. According to the SEM findings, the inhibitor partially covers the metal surface, providing it with a respectable level of protection. The weight loss, electrochemical polarization, EIS, scanning electron microscopy (SEM), and quantum chemical calculations show a strong agreement, indicating that the AO extract is a highly effective inhibitor of aluminum in an acidic solution.
Unveiling the Impact of Drying Methods on Phytochemical Composition and Antioxidant Activity of Anthemis palestina
Different drying techniques may alter the chemical composition of plant extracts and consequently affect their bioactivity potential. The current study was designed to reveal the effect of four different drying methods on the phytochemical composition and antioxidant activity of hydrodistilled essential oil (HD-EO) and methanolic (APM) extract obtained from the aerial part of Anthemis palestina from Jordan. Aerial parts of A. palestina in their fresh (FR) form and after drying in shade (ShD), sun (SD), oven at 40 °C (O40D) and 60 °C (O60D), in addition to microwave (MWD), were used to extract their essential oils by hydrodistillation and to prepare the different methanolic extracts (APM). GC/MS analysis of the different HD-EOs revealed qualitative and quantitative differences among the different samples. While FR, O40D, O60D, and MWD EO samples contained mainly sesquiterpene hydrocarbons (35.43%, 29.04%, 53.69%, and 59.38%, respectively), ShD sample was rich in oxygenated monoterpenes (33.57%), and SD-EO contained mainly oxygenated sesquiterpenes (40.36%). Principal component analysis (PCA) and Cluster analysis (CA) grouped the different drying methods based on their impact on the concentration of chemical constituents. SD-EO demonstrated high DPPH and ABTS antioxidant activity (1.31 ± 0.03) × 10−2; (1.66 ± 0.06) × 10−2 μg/mL, respectively). Furthermore, A. paleistina methanolic extracts (APM) obtained after subjecting the plant to different drying methods showed interesting patterns in terms of their TPC, TFC, antioxidant activity, and phytochemical profiling. Of all extracts, SD-APM extract had the highest TPC (105.37 ± 0.19 mg GA/g DE), highest TFC (305.16 ± 3.93 mg Q/g DE) and demonstrated the highest DPPH and ABTS scavenging activities ((4.42 ± 0.02) × 10−2; (3.87 ± 0.02) × 10−2 mg/mL, respectively); all were supported by correlation studies. LC-MS/MS analysis of the different extracts revealed the richness of the SD-APM extract in phenolic acids and flavonoids.
Does a Rural-Urban Gradient Affect Beetle Assemblages in an Arid Ecosystem?
Urbanization affects all elements of the pre-urban environment, including soils, hydrology, vegetation, and microclimate. Recently, Saudi Arabia has experienced rapid urbanization and growth. Thus, the country’s biodiversity has been threatened. In the Riyadh region, beetle assemblages were assessed along a rural-suburban-urban gradient. A total of 2791 individuals from 94 species belonging to seven families were collected at 15 sites along three different gradients of urbanization in Wadi Hanifa, which runs for a length of 120 km from northwest to southeast. Tenebrionidae dominated abundance (60.1%) and richness (38%). Beetle abundance, evenness, and diversity were not different among habitats; however, species richness was higher in rural habitats. Detrended correspondence “DCA” and canonical correspondence “CCA” analyses showed distinct differences among sites along gradients. Urbanization intensity, soil variables, and land cover were significantly correlated with CCA axis 1, while elevation and flora were significantly correlated with CCA axis 2. The most critical operating environmental variables in Wadi Hanifa were buildings, elevation, soil organic carbon, litter cover, and litter depth, as well as plant species such as Launaea capitata, Lycium shawii, Alhagi graecorum, and Heliotropium currasavicum. Ten species in our study were associated with urban habitats, six with suburban habitats, and seven with rural habitats. Consequently, expanding urban areas may negatively affect the richness and composition of beetles and may result in the loss of some native species.
Global-vector representation of the angular motion of few-particle systems II
The angular motion of a few-body system is described with global vectors which depend on the positions of the particles. The previous study using a single global vector is extended to make it possible to describe both natural and unnatural parity states. Numerical examples include three- and four-nucleon systems interacting via nucleon-nucleon potentials of AV8 type and a 3α system with a nonlocal αα potential. The results using the explicitly correlated Gaussian basis with the global vectors are shown to be in good agreement with those of other methods. A unique role of the unnatural parity component, caused by the tensor force, is clarified in the 0 − 1 state of 4 He. The two-particle correlation function is calculated in the coordinate and momentum spaces to show different characteristics of the interactions employed.