QScience Connect - الأعداد السابقة

Polyvinyl alcohol (PVA)/Na-rich Montmorillonite (MMT) nanocomposites were prepared using solution method to create polymer-clay nanocomposite (PCN) material. The PCN material was studied using X-ray diffraction (XRD), demonstrating polymer-clay intercalation that has a high d-spacing (lower diffraction angles) in the PCN XRD pattern, compared to the pure MMT clay XRD pattern, which has a low d-spacing (high diffraction angles). The nano-scanning electron microscope (NSEM) was used to study the morphological image of the PVA, MMT and PCN materials. The results showed that intercalation that took place between the PVA and MMT produced the PCN material.

The mechanical properties of the pure PVA and the intercalated polymer material were studied. It was found that the small amount of MMT clay made the tensile modulus and percentage of the total elongation of the nano-composite significantly higher than the pure PVA polymer value, due to polymer-clay intercalation. The thermal stability of the intercalated polymer has been studied using thermal analytical techniques such as thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed that the PCN material is more thermally stable than the pure PVA polymer.

We realize noncommutative phase spaces as coadjoint orbits of extensions of the Aristotle group in a two-dimensional space. Through these constructions the momenta of the phase spaces do not commute due to the presence of a naturally introduced magnetic field. These cases correspond to the minimal coupling of the momentum with a magnetic potential.

The anisotropy factor as a function of fiber arrangement, fiber fineness and sample thickness has been derived from the theories of soundwave transformation due to phase changing. The sound absorption coefficient of the anisotropic fibrous material is then theoretically calculated. The fibrous materials were prepared so that the fibers are arranged parallel (perpendicularly laid fiber web called STRUTO technology) in the direction of soundwave propagation or perpendicularly (longitudinally laid fiber web) to the direction of sound propagation. The sound absorption coefficient was measured due to the Impedance tube. The theoretical results are in good agreement with experimental findings.

Harnessing waste energy from the manmade air fields of buildings presents a new area of renewable energy to explore. Due to the unpredictability of the natural wind, this study is to evaluate the practicality for harnessing waste energy from the air conditioner exhaust units which are a more constant and predictable source available in the buildings. A prototype of the micro wind turbine has been designed to minimize the negative effect of the exhaust sources. After the micro wind turbine was manufactured, the performance of the turbine was tested in the selected air conditioner exhaust unit. Increasing the rotor solidity and decreasing the resistance of the generator contribute to improved starting torque and decreased generator break in torque respectively in the design. The power generation of the micro wind turbine increases with an increase of the rotor speed. The 24-hour operation of the prototype presents an observation for both exhaust performance and power generation prediction when the prototype is mounted on the exhaust unit.

The distribution and localization of serotonin immunoreactive cells in the superior colliculus of the porcupine (Hystrix cristata) was studied using the peroxidase-antiperoxidase method and an antiserum against serotonin. The study was performed on four superior colliculus' of porcupine. Serotonin immunoreactivity showed a dense body of positively labelled cells throughout the superior colliculus. These serotonin immunoreactive cells had a characteristic arrangement corresponding to the laminar structures of the superior colliculus. In this study, the densest concentration of serotonin immunoreactive cells was found in a single tier located within the stratum zonale (SZ) and upper part of the stratum griseum superficiale (SGS). The second densest is located within stratum griseum intermedium (SGI) and the third appears as an incomplete layer, found only in the medial and central parts of the stratum griseum profundum (SGP). On the basis of these findings, serotonin has been suggested to be an inhibitory neurotransmitter and neuromodulator in the mammalian superior colliculus.

Background: Attempts to produce greener bromination of 2-acetyl 9H-fluorene with KBr+KBrO3 reagent using fly-ash:H2O catalyst in aqueous media gave 9H-fluorenacylbromides. Generally, the halo-keto compounds possess insect antifeedant activities. Therefore, the insect antifeedant activities of these acyl bromides have been studied using 4^th instar larvae Achoea janataL against castor semilooper. Methods: Solvent free bromination method was used for synthesizing some 9H-fluorenacylbromides. They were characterized by UV, IR, NMR and mass spectroscopic data. Castor-leaf discs were used for evaluation of insect antifeedant activities of the synthesized acyl bromides. Results: The yields of synthesized acyl bromides were over 60%. The physical constants, analytical and spectral data of these ketones has been determined. Halo substituted acyl bromides gave good insect antifeedant activities. Conclusion: Easy handling, non-hazardous and environmentally benign bromination methods have been adopted for synthesizing acyl bromides with good yields. Bromo substituted acyl bromides show better insect antifeedant activity.

Background: The aim of this study was to synthesise some substituted styryl 3,4-dimethoxy phenyl ketones using solvent-free SiO2–H2SO4 catalyzed aldol condensation between 3,4-dimethoxy acetophenone and substituted benzaldehydes under microwave irradiation. Then to characterize them by their analytical, physical and spectroscopic data, and also to study their the spectral correlation and antimicrobial activities. Methods: Solvent free microwave assisted aldol condensation method was used for synthesising 3,4-dimethoxyphenyl chalcones. They were characterised by ultraviolet (UV), infrared (IR), nuclear magnetic resonance (NMR) and mass spectroscopic data. The UV, IR, NMR spectral data were correlated with substituent constants, F and R parameters, using Hammett equation, to study the effect of substituents. The Bauer-Kirby method was used for evaluation of antimicrobial activities of the synthesised chalcones. Results: Yields of synthesised chalcones were more than 85%. The spectral data of these ketones had been correlated, using single and multi-linear regression analysis. These gave a satisfactory degree of correlations with some parameters and a fair degree of correlations with other parameters. Few chalcones gave excellent antimicrobial activities, whereas others gave poor antimicrobial activities. Conclusion Easy handling, non-hazardous and environmentally benign aldol condensation method had been adopted for synthesising chalcones with better yields. Some of the Hammett spectral correlations were found to be satisfactory with the observed spectroscopic data. Halo, methoxy, methyl and nitro substituted compounds had shown excellent antimicrobial activities based on their zone of inhibitions.

The aim of this work was to study the effect of friction time on the microstructure and mechanical properties of alumina 0, 25, 50 wt% yttria stabilized zirconia (YSZ) composite and 6061 aluminium alloy joints formed by friction welding. The alumina-YSZ composites were prepared through slip casting in plaster of Paris molds (POP) and subsequently sintered at 1600°C, while the aluminium rods were machined down using a lathe machine to the dimension required. The welding process was carried out under different rotational speeds and friction times, while friction force (0.5 ton-force) was kept constant. Scanning electron microscopy was used to characterize the interface of the joints structure. The experimental results showed that the friction time has a significant effect on joint structure and mechanical properties.

Background: Depression and obesity are common disorders. Obesity is also predictive of several chronic diseases like hypertension and diabetes. The aim of this study was to evaluate and compare depression frequency of obese patients with hypertension or diabetes. Methods: Weight, height and body mass index (BMI) were measured. The definition of obesity was a body mass index (weight (kg)/height (m)²) ≥ 30 kg/m². Obese patients with hypertension or diabetes were documented. All participants had a Beck Depression Inventory (BDI) evaluation. Results: A total of 389 subjects were included, of whom 100, 101, 92, 96 participants were healthy, obese, obese with hypertension, obese with diabetes, respectively. Beck Depression Inventory scores of obese patients, obese patients with hypertension or diabetes were higher compared to the control group. BDI scores of obese patients with diabetes were higher compared to obese and obese with hypertension subjects. Conclusions: Obesity is a risk for depression and other chronic diseases. Obesity can increase depressive symptoms. The level of depressive symptoms in obese patients varied according to chronic disease type. In the present study, diabetes appears to be more closely related to depression than hypertension.

Trial registry: ANEAH.EK. 25.11.2010.47

With the significant rise in hospital infection management in dental hospitals as well as in hospitals, and in order to identify the distribution of pathogenic bacteria on hands and nasal cavity of workers in a dental hospital, bacteria from the hands and nasal cavities of six dentists and 44 dental hygienists from four dental hospitals were investigated. The results showed Staphylococcus aureus, Staphylococcus capitis, Staphylococcus epidermidis, Staphylococcus hominis, Staphylococcus warneri, Staphylococcus xylosus, Staphylococcus. Lugdunensis, and Neisseria spp., were isolated from the nasal cavity and Staphylococcus aureus, Staphylococcus capitis, Staphylococcus epidermidis, Staphylococcus hominis, Staphylococcus warneri, Staphylococcus xylosus, Staphylococcus leutus, Micrococcus spp., Staphylococcus cohnii, Serratia marcescens, Pseudomonas aeruginosa, Klebsiella pneumonia and Pseudomonas pneumotropica from the hands. An antimicrobial disk diffusion test was conducted on Staphylococcus aureus isolated from the hands and nasal cavity to detect MRSA by means of oxacillin. Two strains were detected. When the genes of penicillin binding protein 2 (mecA) were detected from the 2 strains, MRSA was found from both strains. The results of this investigation on the distribution of various pathogenic bacteria and MRSA on hands and nasal cavity of workers of a dental hospital, will contribute to the basic data for the future infection management in a dental hospital.

Intrahepatic cholangiocarcinomas are rare, aggressive tumours. We discuss an afflicted patient who had relatively larger thrombi disseminated into the right atrium. A 63-year-old female patient with intrahepatic cholangiocarcinoma referred with complaints of swellings on her face, upper half of her body, and both arms. On contrast-enhanced thoracic CT scans and transthoracic echocardiograms of the patient an intraluminal thrombus measuring 36.3 × 25.7 mm extending to the orifice of the right atrium was seen. Thrombolytics were not successful in reducing the dimensions of the thrombus.

Medicinal plants play an important role in human livelihoods. However, the harvest of different organs may be destructive. Sarcocephalus latifolius is a species whose roots are harvested for medicinal purposes. This study was carried out to assess the root characteristics, biomass yield and morphological variations within different habitats of southern Benin. Forty-eight S. latifolius individual plants were randomly selected in three localities, representing four habitats for the species. Information collected was related to height, basal diameter, diameter at breast height, number, depth of insertion and the length and the diameter of the roots. Observations were also made on organ characteristics to identify morphologic variation. The study showed that the optimum development of the root system is established in fallow ground and savannas. The species presents two morphotypes at the stem and root levels. Root biomass varied according to the developmental stage and habitat. A model of root biomass estimation was established and can be used to determine the root biomass within habitats. Across habitat, the number of roots is the major determinant for root biomass yield. Therefore, harvest should take into consideration habitat and the developmental stage according to the use type.

In this paper, a simulation optimization-based decision support tool has been developed to study the capacity enhancement scenarios in a tire manufacturing company located in Iran. This company is experiencing challenges in synchronizing production output with customer demand causing an unbalanced work-in-process (WIP) inventory distribution throughout the tire manufacturing process. However, a new opportunity to increase the supplying of raw materials by fifty percent and increase the expected growth in market demand, necessitate this study of the current company situation. This research supported by the company, is to analyze whether the ongoing production logistics system can respond to the increased market demand, considering the raw material expansion. Implementation of a proposed hybrid push/pull production control strategy, together with the facility capacity enhancement options in bottleneck stations and/or heterogeneous lines within the plant, are investigated by the proposed simulation optimization methodology.

This article is an introduction to a new approach to first principles electronic structure calculation. The starting point is the Hartree-Fock-Roothaan equation, in which molecular integrals are approximated by polynomials by way of Taylor expansion with respect to atomic coordinates and other variables. It leads to a set of polynomial equations whose solutions are eigenstate, which is designated as algebraic molecular orbital equation. Symbolic computation, especially, Gröbner bases theory, enables us to rewrite the polynomial equations into more trimmed and tractable forms with identical roots, from which we can unravel the relationship between physical parameters (wave function, atomic coordinates, and others) and numerically evaluate them one by one in order. Furthermore, this method is a unified way to solve the electronic structure calculation, the optimization of physical parameters, and the inverse problem as a forward problem.

Background: The frequent co-abuse of alcohol and tobacco may suggest that they share some common neurological mechanisms. For example, nicotine acts on Nicotinic acetylcholine receptors (nAChRs) in the brain to release dopamine to sustain addiction. Might nAChRs be entwined with alcohol? Objectives: This review summarizes recent studies on the relationship between alcohol and nAChRs, including the role of nAChRs in molecular biological studies, genetic studies and pharmacological studies on alcohol, which indicate that nAChRs have been potently modulated by alcohol. Methods: We performed a cross-referenced literature search on biological, genetic and pharmacological studies of alcohol and nAChRs. Results: Molecular biological and genetic studies indicated that nAChR (genes) may be important in mediating alcohol intake, but we still lack substantial evidence about how it works. Pharmacological studies proved the correlation between nAChRs and alcohol intake, and the association between nicotine and alcohol at the nAChRs. The positive findings of varenicline (a partial agonist at the α4β2 nAChR, smoking-cessation pharmaceutical) treatment for alcoholism, provides a new insight for treating co-abuse of these two substances. Conclusions: Molecular biological, genetic and pharmacological studies of alcohol at the nAChR level, provide a new sight for preventing and treating the co-abuse of alcohol and nicotine. Given the important role of nAChRs in nicotine dependence, the interaction between alcohol and nAChRs would provide a new insight in finding effective pharmacological treatments, in decreasing or stopping alcohol consumption and cigarette smoking concurrently.

Background: Unwanted hair is one of the most common medical problems affecting women of reproductive age inducing a lot of psychological stress and threatening their femininity and self-esteem. Old methods of removing unwanted hair include shaving, waxing, chemical depilation, and electrolysis, all of which have temporary results. However laser-assisted hair removal is the most efficient method of long-term hair removal currently available. It is desirable to develop a reduced cost photodynamic therapy (PDT) system whose properties should include high efficiency and low side-effects. Method: Mice skin tissues were used in this study and divided into six groups such as controls, free methylene blue (MB) incubation, liposome methylene blue (MB) incubation, laser without methylene blue (MB), free methylene blue (MB) for 3 and 4 h and laser, liposome methylene blue (MB) for 3 h and laser. Methylene blue (MB) was applied to wax epilated areas. The areas were irradiated with CW He-Ne laser system that emits orange-red light with wavelength 632.8 nm and 10 mW at energy density of 5 J/cm² for 10 min. The UV-visible absorption spectrum was collected by Cary spectrophotometer. Results: Methylene blue (MB) is selectively absorbed by actively growing hair follicles due to its cationic property. Methylene blue (MB) untreated sections showed that hair follicle and sebaceous gland are intact and there is no change due to the laser exposure. Free methylene blue (MB) sections incubated for 3 h showed that He:Ne laser induced destruction in hair follicles, leaving an intact epidermis. Treated section with free methylene blue (MB) for 4 h showed degeneration and necrosis in hair follicle, leaving an intact epidermis. Liposomal methylene blue (MB) sections incubated for 3 h showed He:Ne laser induced destruction in hair follicles with intradermal leucocytic infiltration. Conclusion: Low power CW He:Ne laser and methylene blue (MB) offered a successful PDT system in selectively damaging hair follicles, leaving an intact epidermis. The current PDT system provides better outcome than hair destruction through laser heat transfer procedures and laser-mediated hair removal, due to complete destruction of hair follicles.

Background: Hepatic fibrosis results from an imbalance between fibrogenesis and fibrolysis in the liver. The process of Ito cell activation, which is thought to be the central pathogenic mechanism in liver fibrogenesis/cirrhosis, may involve distinct interactions with Kupffer cells (KCs) mediated by various cytokines and growth factors. The aim of this study was to determine whether targeting KC function using GdCl3, which specifically acts on Kupffer cells, interferes with the manifastation of carbon tetrachloride (CCl4) and dimethylnitrosamine (DMN) induced hepatic fibrosis/cirrhosis. Methods: We assesed the change in distribution of ECM proteins, laminin and fibronectin and the marker of HSC activation, alpha-smooth muscle actin (α-SMA) after liver injury and after KC inactivator, GdCl3-treatment with light microscope immunohistochemistry. Using light microscopy, characteristic changes of fibrosis/cirrhosis were seen in the hepatotoxin-administrated groups. Results: The immunohistochemical profile of anti-laminin was significantly altered in hepototoxin-treated groups (p < 0.05) and GdCl3 blocked this effect. The immunoproducts of anti-fibronectin and anti-SMA antibody were not significantly altered in the CCl4-treated group. In contrast, after DMN-induced flbrosis/cirrhosis, laminin, fibronectin and α-SMA staining were significantly increased (p < 0.05) and were present along the sinusoids in cirrhotic liver tissue. However, those ECM proteins and α-SMA staining in the parenchyma and fibrotic nodules decreased but not significantly after GdCl3 treatment. Conclusions: The results suggest that GdCl3 suppressed the activation of lipocytes and their transition from hepatic lipocytes to myofibroblast-like cells in cirrhotic livers in CCl4-treated mice. These results support that treatment with the selective Kupffer cell toxicant GdCl3 prevents stellate cell activation and prevents liver fibrosis/cirrhosis

Background: This study aims to synthesise a series of 1-thiocarbomyl pyrazolines, including 3-(3,4-dibromophenyl)-5-(substituted phenyl)-4,5-dihydro-1H-pyrazole-1-carbothioamides, using solvent-free fly-ash:PTS catalyzed cyclization between chalcones and thiosemicarbazide, under microwave irradiation. Then to characterize them using analytical, physical and spectroscopic data.

Methods: Solvent-free microwave assisted cyclization was adopted for the synthesis of 1-thiocarbomyl, including 3-(3,4-dibromophenyl)-5-(substituted phenyl)-4,5-dihydro-1H- pyrazole-1-carbothioamides, using fly-ash:PTS as the catalyst. They were characterised by IR, NMR and mass spectroscopic data. The infrared (IR) and nuclear magnetic resonance (NMR) spectral data was correlated with substituent constants, F and R parameters, using Hammett equation, to study the effect of substituents.

Results: The yields of the synthesised chalcones were more than 85%. The spectral data of these 3-(3,4-dibromophenyl)-5-(substituted phenyl)-4,5-dihydro-1H-pyrazole-1-carbothioamides had been correlated, using single and multi-linear regression analysis. These gave a satisfactory or fair degree of correlation with some parameters.

Conclusion: Easy handling, non-hazardous and environmentally benign cyclization method had been adopted for the synthesis of 1-thiocarbomyl pyrazolines using fly-ash:PTS as catalyst, with better yields. Some of the Hammett spectral correlations were found to be satisfactory, with the observed spectroscopic data.

This paper shows the combination of an efficient transformation and Exp-function method, to construct generalized solitary wave solutions of the nonlinear Burger's equations of fractional-order. Computational work and subsequent numerical results re-confirm the efficiency of the proposed algorithm. It is observed that the suggested scheme is highly reliable and may be extended to other nonlinear differential equations of fractional order.

We report the discovery of the blister beetle, Meloe coelatus Reiche, 1957, in Qatar. According to the Catalogue of Palaearctic Coleoptera there is no record for the genus Meloe in Qatar, although the genus is well represented in other areas of the Arabian Peninsula. M. coelatus is a rare species, that is present along a wide area of Northern Africa and Western Asia. Our findings bridge the current geographic gap in the known distribution of the species from Saudi Arabia to Iran. We believe the Coleoptera fauna of Qatar might be underestimated. A thorough field survey is recommended in order to document the presence of other species of this family, and also to complete the catalogue of Coleoptera for the State of Qatar.