2,970 research outputs found
Analytical Solution for facilitated transport across a membrane
An analytical expression for the facilitation factor of component A across a liquid membrane is derived in case of an instantaneous reaction A(g)+B(l)AB(l) inside the liquid membrane. The present expression has been derived based on the analytical results of Olander (A.I.Ch.E. J. 6(2) (1960) 233) obtained for the enhancement factor for G–L systems with bulk. The analytical expression for the facilitation factor allows for arbitrary diffusivities of all species involved and does not contain any simplification or approximations. The facilitation factor starts from the value of unity, goes through a maximum and then reduces back to unity as the equilibrium constant is increased. The maximum facilitation factor occurs at higher values of the equilibrium constant as the ratio of the permeate-complex over carrier diffusivity is reduced whereas the maximum facilitation factor occurs at the same value of the equilibrium constant for all values of DA/DB (ratio of the permeate over carrier diffusivity). A similar behavior is seen for the flux of A as a function of the equilibrium constant. The facilitation factor remains constant with changes in the film thickness whereas the flux of A reduces with an increase in the thickness of the film. A linear increase of the facilitation factor and flux of A are seen with increasing initial carrier concentration
Preparation of Some Eco-friendly Corrosion Inhibitors Having Antibacterial Activity from Sea Food Waste
Chitosan is one of the important biopolymers and it is extracted from exoskeletons of crustaceans in sea food waste. It is a suitable eco-friendly carbon steel corrosion inhibitor in acid media; the deacetylation degree of prepared chitosan is more than 85.16 %, and the molecular weight average is 109 kDa. Chitosan was modified to 2-N,N-diethylbenzene ammonium chloride N-oxoethyl chitosan (compound I), and 12-ammonium chloride N-oxododecan chitosan (compound II) as soluble water derivatives. The corrosion inhibition efficiency for carbon steel of compound (I) in 1 M HCl at varying temperature is higher than for chitosan and compound (II). However, the antibacterial activity of chitosan for Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, and Candida albicans is higher than for its derivatives, and the minimum inhibition concentration and minimum bacterial concentration of chitosan and its derivatives were carried out with the same strain
Aligning cloud computing security with business strategy
These days, the technological growth in the IT sector is rapid. Cloud computing is also one of the new technologies that have both benefits and limitations. This paper gives an overview of how cloud computing can be helpful for an enterprise. It emphasizes on how cloud computing can be adopted in the IT sector. The paper also discusses the security issues of cloud computing. This article also highlights the issue of data leakage in this technology which faces cloud computing clients. The authors have designed a model to solve this issue through data isolation. A business value will be achieved through the proposed model by aligning the cloud computing security with the business strategy and increase the security procedures to verify the authenticated users through the virtual system
Multi-layer Biosensor for Pre-symptomatic Detection of Puccinia strifformis, the Causal Agent of Yellow Rust
The yellow rust of wheat (caused by Puccinia striiformis f. sp. tritici) is a devastating fungal infection that is responsible for significant wheat yield losses. The main challenge with the detection of this disease is that it can only be visually detected on the leaf surface between 7 and 10 days after infection, and by this point, counter measures such as the use of fungicides are generally less effective. The hypothesis of this study is to develop and use a compact electrochemical-based biosensor for the early detection of P. striiformis, thus enabling fast countermeasures to be taken. The biosensor that was developed consists of three layers. The first layer mimics the wheat leaf surface morphology. The second layer consists of a sucrose/agar mixture that acts as a substrate and contains a wheat-derived terpene volatile organic compound that stimulates the germination and growth of the spores of the yellow rust pathogen P. s. f. sp. tritici. The third layer consists of a nonenzymatic glucose sensor that produces a signal once invertase is produced by P. striiformis, which comes into contact with the second layer, thereby converting sucrose to glucose. The results show the proof that this innovative biosensor can enable the detection of yellow rust spores in 72 h
In Vitro and In Silico Antioxidant Efficiency of Bio-Potent Secondary Metabolites From Different Taxa of Black Seed-Producing Plants and Their Derived Mycoendophytes
Oxidative stress is involved in the pathophysiology of multiple health complications, and it has become a major focus in targeted research fields. As known, black seeds are rich sources of bio-active compounds and widely used to promote human health due to their excellent medicinal and pharmaceutical properties. The present study investigated the antioxidant potency of various black seeds from plants and their derived mycoendophytes, and determined the total phenolic and flavonoid contents in different extracts, followed by characterization of major constituents by HPLC analysis. Finally, in silico docking determined their binding affinities to target myeloperoxidase enzymes. Ten dominant mycoendophytes were isolated from different black seed plants. Three isolates were then selected based on high antiradical potency and further identified by ITS ribosomal gene sequencing. Those isolated were Aspergillus niger TU 62, Chaetomium madrasense AUMC14830, and Rhizopus oryzae AUMC14823. Nigella sativa seeds and their corresponding endophyte A. niger had the highest content of phenolics in their n-butanol extracts (28.50 and 24.43 mg/g), flavonoids (15.02 and 11.45 mg/g), and antioxidant activities (90.48 and 81.48%), respectively, followed by Dodonaea viscosa and Portulaca oleracea along with their mycoendophytic R. oryzae and C. madrasense. Significant positive correlations were found between total phenolics, flavonoids, and the antioxidant activities of different tested extracts. The n-butanol extracts of both black seeds and their derived mycoendophytes showed reasonable IC50 values (0.81–1.44 mg/ml) compared to the control with significant correlations among their phytochemical contents. Overall, seventeen standard phenolics and flavonoids were used, and the compounds were detected in different degrees of existence and concentration in the examined extracts through HPLC analysis. Moreover, the investigation of the molecular simulation results of detected compounds against the myeloperoxidase enzyme revealed that, as a targeted antioxidant, rutin possessed a high affinity (−15.3184 kcal/mol) as an inhibitor. Taken together, the black seeds and their derived mycoendophytes are promising bio-prospects for the broad industrial sector of antioxidants with several valuable potential pharmaceutical and nutritional applications
Novel Sequence Variants in the NPC1 Gene in Egyptian Patients with Niemann-Pick Type C
BACKGROUND: Niemann-Pick disease type C (NPC) is a rare, autosomal recessive, progressive neuro-visceraldisease caused by biallelic mutations in either NPC1gene (95% of cases) or NPC2 gene.
AIM: This caseseries study aimed at the molecular analysis of certain hot spots of NPC1 genein NPC Egyptian patients.
METHODS: The study included 15 unrelated NPC patients and selected parents,as well as20 healthy controls of matched sex and age. Clinical investigations were performed according to well established clinical criteria. Assessment of the chitotriosidase level, as an initial screening tool for NPC, was done in all cases. Polymerase chain reaction amplification of NPC1 exons (17–25) encountering the hotspot residues (855–1098 and1038–1253) was carried out followed by direct sequencingfor mutational analysis.
RESULTS: All includedpatients with mainly neurovisceral involvement were characterized. The onset of the disease varied from early-infantile (58.3%) to late-infantile (26.7%) and juvenile-onset (6.7%). Ahigh chitotriosidase level wasobservedin all patients. Molecular analysis of NPC1 (exons 17–25) confirmed 15 mutant alleles out of 30 studied ones. They included two novel homozygous missense variants (p.Ser1169Arg and p.Ser1197Phe) and previously reportedfour mutations (p.Arg958*, p.Gly910Ser, p.Ala927Glyfs*38, and andp.Cys1011*).
CONCLUSION: The two studied amino acid residues (855–1098 and 1038–1253) could beconsidered aspotential hotspot regions in NPC1 Egyptian patients
Synthesize of bio-based encapsulated nano urea modified hydroxyapatite for controlling release of nitrogen and enhancing green bean yield
The massive rise in the world population requires increasing food production, and the world needs to decrease agricultural inputs like agrochemicals to preserve natural resources. The low nutrient use efficiency of conventional fertilizers has always been a concern because of their impact on the environment, and they are considered a waste of natural resources, which is against sustainability goals. Their low efficiency is attributed to their high solubility and fast release into the soil. Controlled-release fertilizers (CRFs) can reduce nutrient loss, which increases their efficiency and controls environmental pollution. In this study, single- and double-layers coating of biopolymers were applied to encapsulate nano urea-modified hydroxyapatite to control nitrogen release in soil. Hydroxyapatite was synthesized using the wet chemical precipitation method and two different rodlike and mesoporous hydroxyapatites were obtained. Nano-hydroxyapatite that had been synthesized was mixed with urea in two different amounts: 4:1 and 8:1. Biopolymers were then added on top. The current CRF synthesis strategy focuses on using low-cost, widespread biorefinery materials to decrease the manufacturing cost of CRFs. The nitrogen release rate of the synthesized CRFs and commercial urea in water and soil was studied. In field experiments, the impact of CRFs on green bean growth and yield was studied. The results showed that both single and double-coated CRFs reduced the N release rate in the soil and increased the fertilizer's longevity to 24 days, compared to 6 days for conventional urea. The total yield of green beans increased by 48%-120% by applying 75% of the recommended dose compared with that obtained with the full dose of conventional urea (control). Also, applying double-coated CRFs at N level of 25% of the recommended dose gives a green bean yield equal to the control. The recommended treatment is SC-CRF prepared with C-HA applied at N rate of 75% to match the future increase in the required amount of food
Towards Efficient Energy Usage at Ain Shams University Campus
In the light of global energy transition to renewable resources and energy efficiency usage, Ain Shams University (ASU) developed an ambitious plan to transform its campus into Green Campus. From an energy perspective, energy consumption data were continuously collected and audited to calculate the university campus carbon footprint. An energy usage strategy was established to tackle various pillars such as electrifying the campuses’ transportation system, improving energy efficiency usage, generating Renewable Energy (RE) for self-consumption, etc. Extensive research has been initiated on electric vehicles, wind and solar Photovoltaic (PV) energy generation with students’ activities/competitions. Thus, electric cars and buses were manufactured at the Faculty of Engineering (FoE) for elderly people and staff movement in ASU campus. Solar PV lighting poles with batteries were installed in the main campus. A small-scale Wind Turbine (WT) is manufactured and installed at the FoE and a pilot solar PV system is installed as well. Currently, an energy efficiency project is under implementation in various buildings/faculties and a parking lot that targets energy efficiency and solar PV energy generation. An energy efficiency measure is under implementation through replacing lamps with LED lamps, installing motion sensors, setting up a control center for monitoring and operation that is supported by Artificial Intelligence decision making algorithms. Rooftop solar PV energy systems are under design with smart meters. The project is targeting energy saving and bill reduction by at least 30% and as a result a reduction of carbon footprint will be achieved following the COP27 recommendations
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