119 research outputs found

    Materials Selection, Synthesis, and Dielectrical Properties of PVC Nanocomposites

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    Materials selection process for electrical insulation application was carried out using Cambridge Engineering Selector (CES) program. Melt mixing technique was applied to prepare polyvinyl-chloride- (PVC-) nanofumed silica and nanomontmorillonite clay composites. Surface analysis and particles dispersibility were examined using scanning electron microscope. Dielectrical properties were assessed using Hipot tester. An experimental work for dielectric loss of the nanocomposite materials has been investigated in a frequency range of 10 Hz–50 kHz. The initial results using CES program showed that microparticles of silica and clay can improve electrical insulation properties and modulus of elasticity of PVC. Nano-montmorillonite clay composites were synthesized and characterized. Experimental analyses displayed that trapping properties of matrix are highly modified by the presence of nanofillers. The nanofumed silica and nanoclay particles were dispersed homogenously in PVC up to 10% wt/wt. Dielectric loss tangent constant of PVC-nanoclay composites was decreased successfully from 0.57 to 0.5 at 100 Hz using fillers loading from 1% to 10% wt/wt, respectively. Nano-fumed silica showed a significant influence on the electrical resistivity of PVC by enhancing it up to 1 × 1011 Ohm·m

    Neutrophil CD64 in early-onset neonatal sepsis

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    Background: Neonatal sepsis is a life threatening disease with an incidence of 3.5 to 8 cases per 1,000 live births; and mortality rate 16 to 30%. Cytokines, produced by monocytes, macrophages, and endothelial cells in response to infectious stimuli are important proinflammatory mediators in the early phases of the sepsis syndrome. Elevated serum levels of interleukin-6 (IL-6) had been found in both neonatal and adult sepsis. However, for neonatal sepsis, little is known about a group of molecules playing a central role in the innate immune system. Among them is the neutrophil CD64 which is expressed on neutrophil surface in many inflammatory conditions. Objective: To study the neutrophil CD64 expression in neonates with early onset sepsis and its relation to other laboratory markers as IL6, CRP, total leucocytic count and platelet count. Methods: This study comprised 30 neonates with a gestational age of 28 to 40 weeks with a picture of early onset neonatal sepsis within 48 hours of life admitted to neonatal care unit, Suzan Mubarak Hospital, El-Minia University, Egypt during the period from February, 2008 to January, 2009 and 20 healthy neonates age and sex matched as a control group. Neutrophil surface expression of CD64 was quantified with flow cytometry. We measured plasma IL6, C-reactive protein, complete blood count and blood culture. Results: Neutrophil CD64 expression was increased significantly in neonates with neonatal sepsis than controls (p=0.001). Cases with history of premature rupture of membranes (PROM) ≥48 hours, with positive blood culture or poor outcome had the highest levels of neutrophil CD64 expression (528±50.7, 558±58.4 and 560.9±43.9 relative fluorescence units (RFU) respectively). A significant positive correlation was found between CD64 levels and the levels of IL6 (r=0.71, p=0.001),C-reactive protein (r=0.74, p=0.001) and total leucocytic count (r=0.76 ,p=0.01) and negative correlation with gestational age (r=-0.92, p=0.001) and body weight (r=-0.92, p=0.006), but there was no correlation between it and platelet count (r=-0.32, p=0.08). Conclusion: Neutrophil CD64 expression is increased in neonates with early-onset neonatal sepsis and correlated well with other laboratory markers of sepsis.Keywords: Neonatal sepsis, Cytokines, Neutrophil CD64, IL6, PROMEgypt J Pediatr Allergy Immunol 2010;8(1):19-2

    An alkali catalyzed trans-esterification of rice bran, cottonseed and waste cooking oil

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    In this research work, biodiesel production by trans-esterification of three raw materials including virgin and used edible oil and non edible oil has been presented. A two step method following acidic and alkali catalyst was used for non edible oil due to the unsuitability of using the straight alkaline-catalyzed trans-esterification of high FFA present in rice bran oil. The acid value after processing for rice bran, cottonseed and waste cooking oil was found to be 0.95, 0.12 and 0.87 respectively. The influence of three variables on percentage yield i.e., methanol to oil molar ratio, reaction temperature and reaction time were studied at this stage. Cottonseed oil, waste cooking oil and rice bran oil showed a maximum yield of 91.7%, 84.1% and 87.1% under optimum conditions. Fuel properties of the three biodiesel satisfied standard biodiesel fuel results

    Phytochemical Screening, Gas Chromatography-mass Spectrometry Analysis, and Antidiabetic Effects of Corchorus olitorius Leaves in Rats

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    BACKGROUND: Therapies for diabetes mellitus are still meeting failure in most cases, especially in the developed stages of the disease due to incredible associating complications. Hence, there is a need for continuous development of curative therapies for that stubborn disease. AIM: We aimed to investigate the antidiabetic effects of one of the most popular plants cultivated in Egypt, C. olitorius. METHODS: Phytochemical screening of total alcoholic extract of Corchorus olitorius leaves and its aqueous and chloroform fractions revealed the presence of flavonoids, saponins, carbohydrates, tannins, coumarins, and alkaloids. RESULTS: The gas chromatography-mass spectrometry analysis showed the presence of 12 and nine chemical compounds in aqueous and chloroform extracts, respectively. C. olitorius decreased serum glucose level and α-amylase activity. This effect was more pronounced in the total alcoholic extract and its chloroform fraction than the aqueous one. The extracts also adjusted the lipid profile, reduced liver injury parameters, and caused remarkable improvement and increase number, size, and density of functioning β-cells. CONCLUSION: The findings suggest the antihyperglycemic and antioxidant effects of C. olitorius besides its beneficial effect on diabetic complications such as hyperlipidemia and liver injury. The presence of some phytochemicals such as theophylline, trans-2, 3-dimethoxycinnamic acid, 7-hydroxy-4-methyl coumarin, apigenin 7-glucoside, and glycitein may contribute to such pharmacological effects

    Electrochemical Activation of Graphene at Low Temperature: The Synthesis of Three-Dimensional Nanoarchitectures for High Performance Supercapacitors and Capacitive Deionization

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    An electrochemical technique is developed to activate graphene oxide (GO) at relatively low temperature and assemble it into porous electrodes. The activation process is carried out in molten KOH by switching the polarity between 2 symmetrical GO electrodes. The electrochemically activated graphene (ECAG) showed a specific surface area as high as 2170 m<sup>2</sup> g<sup>–1</sup> and nanometer-sized pore created at a temperature as low as 450 °C. The ECAG electrode shows a significant enhancement in the electrochemical activity and thus improved electrochemical performance when being used as electrodes in supercapacitors and capacitive deionization (CDI) cells. A specific capacitance of 275 F g<sup>–1</sup> is obtained in 6 M KOH electrolyte, and 189 F g<sup>–1</sup> in 1 M NaCl electrolyte, which maintains 95% after 5000 cycles. The desalination capacity of the electrodes was evaluated by a batch mode electrosorption experiment. The ECAG electrode was able to remove 14.25 mg of salts per gram of the active materials and satisfy a high adsorption rate of 2.01 mg g<sup>–1</sup> min<sup>–1</sup>. The low energy consumption of the CDI system is demonstrated by its high charge efficiency, which is estimated to be 0.83

    Endophytic Aspergillus hiratsukae mediated biosynthesis of silver nanoparticles and their antimicrobial and photocatalytic activities

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    In the current study, endophytic Aspergillus hiratsukae was used for the biosynthesis of silver nanoparticles (Ag-NPs) for the first time. The characterizations were performed using X ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX), Dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), and UV–Vis spectroscopy. The obtained results demonstrated the successful formation of crystalline, spherical Ag-NPs with particle diameters ranging from 16 to 31 nm. The FT-IR studied and displayed the various functional groups involved, which played a role in capping and reducing agents for Ag-NPs production. The SEM–EDX revealed that the main constituent of the AS-formed sample was primarily Ag, with a weight percentage of 64.2%. The mycosynthesized Ag-NPs were assessed for antimicrobial as well as photocatalytic activities. The antimicrobial results indicated that the synthesized Ag-NPs possess notable antibacterial efficacy against Staphylococcus aureus, Bacillus subtilis, and Escherichia coli, with minimum inhibitory concentrations (MICs) of Ag-NPs ranging from 62.5 to 250 μg/mL. Moreover, the biosynthesized Ag-NPs demonstrated weak antifungal activity against Aspergillus brasiliensis and Candida albicans, with MICs of 500 and 1,000 μg/mL, respectively. In addition, the mycosynthesized Ag-NPs exhibited photocatalytic activity toward acid black 2 (nigrosine) dye under both light and dark stimulation. Notably, After 300 min exposure to light, the nigrosine dye was degraded by 93%. In contrast, 51% degradation was observed after 300 min in darkness. In conclusion, Ag-NPs were successfully biosynthesized using endophytic A. hiratsukae and also exhibited antimicrobial and photocatalytic activities that can be used in environmental applications

    Sinteza i biološko djelovanje novih 1-benzil i 1-benzoil 3-heterocikličkih derivata indola

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    Starting from 1-benzyl- (2a) and 1-benzoyl-3-bromoacetyl indoles (2b) new heterocyclic, 2-thioxoimidazolidine (4a,b), imidazolidine-2,4-dione (5a,b), pyrano(2,3-d)imidazole (8a,b and 9a,b), 2-substituted quinoxaline (11a,b–17a,b) and triazolo(4,3-a)quinoxaline derivatives (18a,b and 19a,b) were synthesized and evaluated for their antimicrobial and anticancer activities. Antimicrobial activity screening performed with concentrations of 0.88, 0.44 and 0.22 g mm2 showed that 3-(1-substituted indol-3-yl)quinoxalin-2(1H)ones (11a,b) and 2-(4-methyl piperazin-1-yl)-3-(1-substituted indol-3-yl) quinoxalines (15a,b) were the most active of all the tested compounds towards P. aeruginosa, B. cereus and S. aureus compared to the reference drugs cefotaxime and piperacillin, while 2-chloro-3-(1-substituted indol-3-yl)quinoxalines (12a,b) were the most active against C. albicans compared to the reference drug nystatin. On the other hand, 2-chloro-3-(1-benzyl indol-3-yl) quinoxaline (12a) display potent efficacy against ovarian cancer xenografts in nude mice with tumor growth suppression of 100 0.3 %.U radu je opisana sinteza, antimikrobno i antitumorsko djelovanje heterocikličkih derivata indola. Polazeći iz 1-benzil- i 1-benzoil-3-bromacetil indola (2a i 2b) sintetizirani su novi heterociklički spojevi 2-tioksoimidazolidini (4a,b), imidazolidin-2,4-dioni (5a,b), pirano(2,3-d)imidazoli (8a,b i 9a,b), 2-supstituirani kinoksalini (11a,b–17a,b) i triazolo(4,3-a)kinoksalini (18a,b i 19a,b). Sintetizirani spojevi testirani su na antimikrobno i antitumorsko djelovanje. Ispitivanje antimikrobnog djelovanja provedeno je s koncentracijama otopina 0,88, 0,44 i 0,22 g mm2 i uspoređeno s referentnim lijekovima cefotaksimom i piperacilinom. Rezultati pokazuju da su 3-(1-supstituirani indol-3-il)kinoksalin-2(1H)oni (11a,b) i 2-(4-metil piperazin-1-il)-3-(1-supstituirani indol-3-il) kinoksalini (15a,b) najaktivniji spojevi na sojeve P. aeruginosa, B. cereus i S. aureus, dok su 2-klor-3-(1-supstituirani indol-3-il)kinoksalini (12a,b) najaktivniji na C. albicans (usporedba s nistatinom). Osim toga, 2-klor-3-(1-benzil indol-3-il) kinoksalin (12a) pokazuje veliku učinkovitost na tumore ovarija miševa (supresija rasta tumora 100 0,3 %)

    Early-infantile onset epilepsy and developmental delay caused by bi-allelic GAD1 variants

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    Gamma-aminobutyric acid (GABA) and glutamate are the most abundant amino acid neurotransmitters in the brain. GABA, an inhibitory neurotransmitter, is synthesized by glutamic acid decarboxylase (GAD). Its predominant isoform GAD67, contributes up to ∼90% of base-level GABA in the CNS, and is encoded by the GAD1 gene. Disruption of GAD1 results in an imbalance of inhibitory and excitatory neurotransmitters, and as Gad1−/− mice die neonatally of severe cleft palate, it has not been possible to determine any potential neurological dysfunction. Furthermore, little is known about the consequence of GAD1 disruption in humans. Here we present six affected individuals from six unrelated families, carrying bi-allelic GAD1 variants, presenting with developmental and epileptic encephalopathy, characterized by early-infantile onset epilepsy and hypotonia with additional variable non-CNS manifestations such as skeletal abnormalities, dysmorphic features and cleft palate. Our findings highlight an important role for GAD1 in seizure induction, neuronal and extraneuronal development, and introduce GAD1 as a new gene associated with developmental and epileptic encephalopathy

    Hydrogen and Carbon Nanotubes from Pyrolysis-Catalysis of Waste Plastics: A Review

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    More than 27 million tonnes of waste plastics are generated in Europe each year representing a considerable potential resource. There has been extensive research into the production of liquid fuels and aromatic chemicals from pyrolysis-catalysis of waste plastics. However, there is less work on the production of hydrogen from waste plastics via pyrolysis coupled with catalytic steam reforming. In this paper, the different reactor designs used for hydrogen production from waste plastics are considered and the influence of different catalysts and process parameters on the yield of hydrogen from different types of waste plastics are reviewed. Waste plastics have also been investigated as a source of hydrocarbons for the generation of carbon nanotubes via the chemical vapour deposition route. The influences on the yield and quality of carbon nanotubes derived from waste plastics are reviewed in relation to the reactor designs used for production, catalyst type used for carbon nanotube growth and the influence of operational parameters
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