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Abstract: Hydrogen plasma etching of graphite generates radicals that can be used for diamond synthesis by chemical vapor deposition (CVD). We studied the etching of polycrystalline graphite by a hydrogen microwave plasma, growth of diamond particles of the non-seeded graphite substrates, and characterized the diamond morphology, grain size distribution, growth rate, and phase purity. The graphite substrates served simultaneously as a carbon source, this being the specific feature of the process. A disorder of the graphite surface structure reduces as the result of the etching as revealed with Raman spectroscopy. The diamond growth rate of 3 – 5 µm/h was achieved, the quality of the produced diamond grains improving with growth time due to inherently nonstationary graphite etching process. Keywords: Microwave plasma, diamond deposition, hydrogen plasma, graphite, etching. |
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Abstract: The effects of Vernonia amygdalina leaf on the nutritional and biochemical parameters in alloxan-induced diabetic rat were investigated. Vernonia amygdalina (VA)leaf was squeeze-washed, dried, pulverized and mixed with standard feed at 2.5%, 5%, 10% and 20%. The proximate nutrient composition of the standard and prepared rations was determined. The Vernonia amygdalina incorporated rations and standard ration were fed to alloxan-induced diabetic rats for 70 consecutive days. Thereafter the nutritional and biochemical parameters as well as the histopathology of pancreasvital organs of the treated rats were determined. The Vernonia Amygdalina at 2.5% inclusion rate significantly (p < 0.05) reversed the nutritional indices and biochemical parameters which were compromised in diabetic rats fed with standard ration alone. The VA also reversed the degenerative changes in the pancreatic islet induced by alloxan. Vernonia Amygdalina has potent antidiabetic activity and its incorporation in excess of 5% in the diet should be avoided. Keywords: Alpha amylase, apparent digestibility, biological value, cholesterol, gas chromatography, glycosylated haemoglobin. |
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Abstract: Carbonic anhydrase is an enzyme which has the zinc as the metallic part of it. This enzyme catalyzes the reversible reaction of turning carbon dioxide into bicarbonate. In this research the mechanism of inhibition a new class of inhibitor of this enzyme, glycosyl coumarin has been modeled using the density functional theory (DFT). First, the most constant confirmer of this four coumarin sugar derivatives which includes galactose, mannose, ribose and glucose has been selected and then they had been interacted as inhibitor with CA (II) enzyme’s active site. In further for showing the effect of sugar in these molecules, coumarin itself had been chosen as inhibitor and the inhibitory effect is surveyed. All calculations have been done by density functional theory in level of B3LYP with basic set 6-31G* and with Minnesota function M06 with basic set 6-31+G*.Thermodynamic functions like enthalpy of formation, entropy of formation and Gibbs free energy for CA-inhibitor have been computed. The results indicate that the reaction among these groups of inhibitors and Carbonic anhydrase is not of the type of direct and syndetic but the enzyme is deactivated with space effect and addition to this, the computed thermodynamic functions show that although this coumarin sugar derives have deterrence in the range of micro molar but, coumarin without sugar is a stronger deterrence for CA II. Finally, the interaction between the most constant confirmer (galactose coumarin) is surveyed as the best deterrence using the explicit solvent method. Keywords: Carbonic Anhydrase, glycosylcoumarin, inhibition mechanism, Density functional theory, explicit solvent method. |
Abstract :Lathosterol and Noncholesterol Sterols in Routine Use for the Differentiation and Monitoring of Dietary and Drug Induced Treatment of Hypercholesterolemias in Children and Adolescents
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Abstract: Aims: The authors discuss their 15 years of experience with use of noncholesterol sterols (NCS) when diagnosing heterozygous familial hypercholesterolemia (HFH) and the dietary and drug treatment of children and adolescents when lathosterol (Lat) and desmosterol (Des) as cholesterol synthesis precursors, and campesterol (Cam) and sitosterol (Sit) as cholesterol absorption precursors are included. Patients and Methods:38 children and adolescents (6-18 yrs) with HFH proven by molecular genetic testing of LDL-cholesterol deficit; 107 children patients with clinical and laboratory symptoms of other hypercholesterolemias; 84 healthy school-age children as a control group. Routine lipid spectrum scan—total cholesterol (TCh), LDL-Ch, HDL-Ch, TAG, with additional apo A1, apo B, Lp (a), LDL-receptors, apo E polymorphism; Lat, Des, Cam and Sit in the plasma—was established by means of GC/MS. Results: The HFH patients on a low cholesterol diet (LCHD) who come to our lipid outpatient clinic have elevated levels of Lat and Des, unlike patients with alimentary hypercholesterolemia (p<0, 001). Lat and Des levels are high following interruption of medical treatment during long vacations or when drug treatment is neglected. Administration of statins only in sufficiently high therapeutic doses reduces Lat and Des (p<0, 001). Compensatory elevation of Cam and Sit occurs only in few pediatric patients. Ezetimibe decreases Cam and Sit more efficiently than Lat or Des. Combination of statin with ezetimibe is most efficient in decrease of not only TCh but also Lat and Des, as well as Cam and Sit. Conclusions: Extending the laboratory spectrum by precursors of cholesterol synthesis and absorption improves the differential diagnosis of HFH and makes monitoring and/or treatment of children and adolescents more precise. Keywords: Noncholesterol sterols, lathosterol, desmosterol, campesterol, sitosterol, phytosterols, heterozygous familial hypercholesterolemia, statins, ezetimibe, dietary and drug treatment.Download Full Article |
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Abstract: Morinda citrifolia (Noni) is a traditional folk medicinal plant and has a long history of use as a food and medicine. In order to reveal the effects of Noni fruit juice (NFJ) on stroke prevention, we performed experiments using spontaneously hypertensive stroke prone (SHRSP) rats. NFJ did not change rat body weight, food intake, and water intake. However, both systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly decreased after NFJ treatment in SHRSP rats. Furthermore, NFJ significantly increased the survival rate, urinary nitric oxide (NO) concentration was significantly higher in the NFJ group, and endothelial NO synthase (eNOS) phosphorylation levels increased in the brain after NFJ treatment. Two pathways regulate eNOS phosphorylation: the insulin-dependent pathway and the insulin-independent pathway. For the insulin-dependent pathway, phosphorylation of insulin receptor substrate 1 (IRS1) and protein kinase B (Akt) did not change in the NFJ group. For the insulin-independent pathway, expression of adenosine monophosphate-activated protein kinase (AMPK) phosphorylation, liver kinase B 1 (LKB1), and silent information regulator 1 (Sirt1) significantly increased in the brain of SHRSP rats after NFJ treatment. These data suggested that NFJ prevented stroke by improved blood circulation, increased NO production, and elevated eNOS phosphorylation by stimulating the insulin-independent pathway (Sirt1-LKB1-AMPK-eNOS). Keywords: Morinda citrifolaia, stroke, spontaneously hypertensive stroke prone rats, nitric oxide, endothelial nitric oxide synthase. |