Rice hulls (RH) and bean hulls (BH) were subjected to prehydrolysis treatments, to define the optimum conditions for producing a high percentage of hydrolyzed hemicellulose with a small or moderate ...degradation of the cellulosic portion. The hydrolysis experiments were performed using hydrochloric and sulfuric acids in concentrations ranging from (0.5 to 5)% (w/w) at 120°C for 90min and 10% consistency. The effects of different temperatures (80 to 120°C) and time (30 to 120min) on acid hydrolysis of lignocellulosic materials were recorded. It was found that, the optimum condition to hydrolyze the lignocellulosic materials (RH) and (BH) are 2% (w/w) of mineral acid at 120°C for 90min and 10% consistency. The cellulose crystallinity index in the different types of lignocellulosic materials with and without acid treatment, were increased from 0.32 to 0.46 in case of RH and from 0.43 to 0.61 in case of BH. Due to the lignin depolymerization during the pretreatment process, the relative absorbency of the methoxyl group and the aromatic rings bands were lowered for the pretreated than the untreated lignocellulosic materials. Also, the band at 1730cm−1 which is attributed to carbonyl groups of uronic acids was lowered due the hemicellulose hydrolysis.
Summary
Actinomycetes are a rich source for secondary metabolites with a diverse array of biological activities. Among the various genera of actinomycetes, the genus Saccharopolyspora has long been ...recognized as a potential source for antibiotics and other therapeutic leads that belong to diverse classes of natural products. Members of the genus Saccharopolyspora have been widely reported from several natural sources including both terrestrial and marine environments. A plethora of this genus has been chemically investigated for the production of novel natural products with interesting pharmacological effects. Therefore, Saccharopolyspora is considered one of the pharmaceutical important genera that could provide further chemical diversity with potential lead compounds. In this review, the literature from 1976 until December 2018 was covered, providing a comprehensive survey of all natural products derived from this genus and their semi‐synthetic derivatives along with their biological activities, whenever applicable. Moreover, the biological diversity of Saccharopolyspora species and their habitats were also discussed.
Production of biohydrogen has the potential to be a renewable alternative to current technologies. There are varieties of technologies for biological hydrogen production mechanisms including ...biophotolysis, photo fermentation, dark fermentation and hybrid biohydrogen production by electrochemical processes. In these studies, a review on the recent developments of biohydrogen production is presented. First, the theoretical principles of biophotolysis by cyanobacteria and green micro algae, as well as direct and indirect of biophotolysis process on hydrogen production are described. Secondly, practical aspects and fundamental of biological hydrogen production processes by photo and dark fermentation are reviewed. This work also involved comparison of the maximum H2 yield, bacterial strains, operating condition, suitable substrates, and mathematical models for fermentative hydrogen production. A new hybrid biological hydrogen production processes by using the electrochemical process is then proposed. This study can also be used to improve the basic and current knowledge about the performance of the biophotolysis, fermentative and electrochemical process in producing hydrogen gas as the alternate fuel.
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•Synthesis and antimicrobial activity of some new 3,4-dihydrothieno2,3-dpyrimidines.•Compounds 7, 8a, 10b, 10d and 11b exhibited half the potency of levofloxacine against Pseudomonas ...aeruginosa.•Compounds 5a, 8b, 10c and 12 displayed half the potency of levofloxacine against Proteus Vulgaris.•Compounds 7, 10b, 10d and 11b showed half the activity of ampicillin against the Gram-positive bacterium, B. subtilis.
In continuation of our research program aiming at developing new potent antimicrobial agents, new series of substituted 3,4-dihydrothieno2,3-dpyrimidines was synthesized. The newly synthesized compounds were preliminary tested for their in vitro activity against six bacterial and three fungal strains using the agar diffusion technique. The results revealed that compounds 7, 8a, 10b, 10d and 11b exhibited half the potency of levofloxacine against the Gram-negative bacterium, Pseudomonas aeruginosa, while compounds 5a, 8b, 10c and 12 displayed half the potency of levofloxacine against Proteus Vulgaris. Whereas, compounds 7, 10b, 10d and 11b showed half the activity of ampicillin against the Gram-positive bacterium, B. subtilis. Most of the compounds showed high antifungal potency. Compounds 3, 6, 7, 9b, 10a, 11a, 11b, 15 and 16 exhibited double the potency of clotrimazole against A. fumigatus. While compounds 3, 4, 5a, 5b, 9b, 10a, 10b, 10c, 13, 15, 16 and 18 displayed double the activity of clotrimazole against R. oryazae. Molecular docking studies of the active compounds with the active site of the B. anthracis DHPS, showed good scoring for various interactions with the active site of the enzyme compared to the co-crystallized ligand.
•Occupational health effects have been rarely integrated in performance optimization models.•Poor ergonomic (human factors) design increases employee performance losses at work.•We develop a modeling ...approach considering health-related productivity and quality losses.•A cost optimization model is developed by integrating employee performance losses.•We evaluate the effects of the ergonomic design on a serial system’s working performance.
Work-related health problems cause an operator to be in different health-states and to have different performance levels in terms of productivity and the number of defective items produced. Human factors studies usually investigate workplace risk factors to reduce the negative effects of occupational health problems. However, they rarely optimize the performance of operation systems. To this end, this paper presents an analytical modeling framework integrating human factor aspects (workplace risk factors) into a serial assembly system performance optimization model. First, a health-state Markov chain is developed to model an employee’s work-related health conditions, which varies due to workplace risk factor exposure levels. Then, the total cost of the assembly system is minimized with respect to incorporating operational and financial consequences of the work-related health-states with other features of the system such as customer demand, inventory capacity and production costs. Ultimately, this study compares the optimum total cost of the system with and without including human factors. The results of numerical analysis show that the total cost increases from 0.1 percent to 32 percent in the presence of different workplace risk factors. This research opens a new window to considering a human factors (ergonomic) intervention not only as an occupational health and safety solution, but also as an operation improvement method leading to the design of safer and more efficient systems. Managers may also take the advantages of this study by having more opportunities to better deal with production variations via improving workplace ergonomic conditions.
Waste tire rubber constitute a serious worldwide problem due to the lack of landfills and the health hazards associated with these landfills. In addition to the environmental motivation for providing ...a means of recycling large quantities of waste tire rubbers, the use of tire rubber particles provides a new type of concrete that has unique mechanical and fracture criteria. This paper presents the results of recent experimental investigations on rubber concrete. Chipped and crumbed tire rubber particles were used to replace coarse and fine aggregate with different volume replacement levels. The mechanical and fracture properties of rubber concrete were examined. Quasi-brittle fracture mechanics models are used to determine the effect of incorporating tire rubber particles on the fracture performance of rubber concrete. Finally, some microstructural features of rubber concrete are also reported. It is concluded that the choice of the optimal replacement ratio of the tire rubber particles can yield concretes with desirable strength and fracture toughness criteria for different applications.
In this study, two biomass-based adsorbents were used as new precursors for optimizing synthesis conditions of a cost-effective powdered activated carbon (PAC). The PAC removed dyes from an aqueous ...solution using carbonization and activation by KOH, NaOH, and H
SO
. The optimum synthesis, activation temperature, time and impregnation ratio, removal rate, and uptake capacity were determined. The optimum PAC was analyzed and characterized using Fourier-transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), a field emission scanning electron microscope (FESEM), Zeta potential, and Raman spectroscopy. Morphological studies showed single-layered planes with highly porous surfaces, especially PAC activated by NaOH and H
SO
. The results showed that the experimental data were well-fitted with a pseudo-second-order model. Based on Langmuir isotherm, the maximum adsorption capacity for removing methylene blue (MB) was 769.23 mg g
and 458.43 mg g
for congo red (CR). Based on the isotherm models, more than one mechanism was involved in the adsorption process, monolayer for the anionic dye and multilayer for the cationic dye. Elovich and intraparticle diffusion kinetic models showed that rubber seed shells (RSS) has higher α values with a greater tendency to adsorb dyes compared to rubber seed (RS). A thermodynamic study showed that both dyes' adsorption process was spontaneous and exothermic due to the negative values of the enthalpy (ΔH) and Gibbs free energy (ΔG). The change in removal efficiency of adsorbent for regeneration study was observed in the seventh cycles, with a 3% decline in the CR and 2% decline in MB removal performance. This study showed that the presence of functional groups and active sites on the produced adsorbent (hydroxyl, alkoxy, carboxyl, and π - π) contributed to its considerable affinity for adsorption in dye removal. Therefore, the optimum PAC can serve as efficient and cost-effective adsorbents to remove dyes from industrial wastewater.
P-glycoprotein (P-gp) imparts multi-drug resistance (MDR) on the cancers cell and malignant tumor clinical therapeutics. We report a class of newly designed and synthesized oxygen-heterocyclic-based ...pyran analogues (4a-l) bearing different aryl/hetaryl-substituted at the 1-postion were synthesized, aiming to impede the P-gp function. These compounds (4a-l) have been tested against cancerous PC-3, SKOV-3, HeLa, and MCF-7/ADR cell lines as well as non-cancerous HFL-1 and WI-38 cell lines to determine their anti-proliferative potency.The findings demonstrated the superior potency of 4a-c with 4-F, 2-Cl, and 3-Cl derivatives and 4h,g with 4-NO
, 4-MeO derivatives against PC-3, SKOV-3, HeLa, and MCF-7/ADR cell lines.Compounds 4a-c were tested for P-gp inhibition and demonstrated significant vigour against MCF-7/ADR cells with IC
= 5.0-10.7 μM. The Rho123 accumulation assay showed that compounds 4a-c adequately inhibited P-gp function, as predicted. Furthermore, 4a or 4b administration resulted in MCF-7/ADR cell accumulation in the S phase, while compound 4c induced apoptosis by causing cell cycle arrest at G2/M. The molecular docking was applied to understand the likely modes of action and guide us in the rational design of more potent analogs. The investigate derivatives showed their good binding potential for p-gp active site with excellent docking scores and interactions. Finally, the majority of investigated derivatives 4a-c derivatives showed high oral bioavailability, but they did not cross the blood-brain barrier. These results suggest that they have favorable pharmacokinetic properties. Therefore, these compounds could serve as leads for designing more potent and stable drugs in the future.
•The mechanical strength of the concrete increases with the decrease in paste-aggregate ratio.•Compressive strength of 70 MPa – 90 MPa was obtained.•The concrete exhibit excellent deformation and ...durability characteristics.•The water absorption decreases with the increase in the aggregate content.
This paper is aimed to investigate the engineering properties of high calcium fly ash-based one-part geopolymer concrete using different paste aggregate ratio (0.57, 0.45 and 0.35) and curing conditions (ambient curing, solar curing, and water curing). High calcium fly ash was activated with anhydrous sodium metasilicate powder at 12% of the total precursor materials and cured at three different curing conditions. Workability, compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, Poisson’s ratio, water absorption, and porosity have been investigated. The experimental results showed that the mechanical strength of one-part alkali-activated concrete (OPAAC) increases with the decrease in paste aggregate ratio across all the curing methods considered. The strength growth for ambient and water cured specimens is gradual and almost comparable to the solar cured specimens. Compressive strength of almost 70 MPa was obtained for ambient and water cured OPAAC and 90 MPa for solar-cured OPAAC. The paste aggregate ratio has little effect on the porosity of the OPAAC. Regardless of the curing methods, the developed one-part alkali-activated concrete exhibits excellent deformation and durability properties.
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•Long-term intermittent hypoxia (IH) induces memory deficits and hippocampal oxidative stress.•Resveratrol ameliorates IH-induced spatial memory deficits in young rats.•Resveratrol ...reduces IH-induced hippocampal oxidative stress challenge.•Resveratrol protects against IH-induced hippocampal Oxidative DNA damage.•Resveratrol attenuates the IH-induced expression of P47Phox subunit of NADPH oxidase.
Long-term intermittent hypoxia (IH) is a characteristic hallmark of obstructive sleep apnea (OSA) and causes most of the neurological aspects of OSA, such as spatial memory and learning deficits. These deficits are accompanied by an increase in oxidative stress and inflammation in brain areas involved in cognition, such as the hippocampus, particularly in children. Resveratrol is a natural polyphenolic compound with potent antioxidant, anti-inflammatory and neuroprotective properties.
The aim of this work is to study the possible protective effect of resveratrol against IH-induced neurobehavioral deficits and to investigate the possible mechanism of this protective effect in the young rat model of OSA.
The effect of resveratrol (5 and 10mg/kg, orally) on anxiety, spatial memory and learning deficits in young rats exposed to IH for 6 weeks and the corresponding biochemical changes were studied.
Resveratrol attenuated IH-induced anxiety and spatial memory deficits, as indicated by the elevated plus maze and Morris water maze tests, respectively, in a dose-dependent manner. In addition, resveratrol antagonized IH-induced increases in hippocampal glutamate, TBARS and 8-OHdG levels and p47Phox expression and decreases in GSH levels and GSH-Px activity in the hippocampus of IH-exposed young rats.
Resveratrol ameliorates IH-induced anxiety and spatial learning deficits through multiple beneficial effects on hippocampal oxidative pathways that involve decreased expression of the p47Phox subunit of NADPH oxidase. Hence, the potential therapeutic role of resveratrol in OSA may be utilized in the near future and deserves further exploration.
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