Exocrine function of the pancreas in patients with chronic hepatitis and liver cirrhosis of various etiologies

Exocrinous performance of the pancreatic gland under secretin-pancreozymin stimulation was studied in 76 patients with chronic diffuse diseases of the liver who were distinguished into 6 groups: those who suffered from chronic persistent hepatitis of viral and alcohol origin, chronic active hepatitis of viral origin, cirrhosis of the liver of viral and alcohol origin, primary biliary hepatocirrhosis. The results obtained were correlated with those from 11 normal persons (controls). Out of 76 examinees the disorders of exocrinous performance of the pancreatic gland were revealed in 75 persons. The most characteristic features were: a decrease in the basal and an increase in the stimulated volume of the pancreatic juice; a reduction of both basal and stimulated production of bicarbonates; a decrease in the trypsin and amylase fasting levels and their increment in the stimulated juice of the pancreatic gland. Disorder in the production of bicarbonates was stated as a most characteristic feature in the patients both with viral and alcohol origin of the disease but it was mostly manifest in the patients with hepatocirrhosis. Pronounced elevation of the activity of amylase and trypsin in the pancreatic juice was observed in patients with very high activity of disease development and in the patients who continuously used large amounts of alcohol. The authors suspected that alcohol abuse and the effect of hepatitis virus had an equal pathogenic impact on the liver and pancreatic gland.     

Significance of thiophenic compounds distribution in correlating crude oils into source related types

Gas chromatography and combined gas chromatography/mass spectrometry were used to characterize different thiophenic compounds in representative petroleum from the Gulf of Suez. An evaluation of the distribution patterns of these compounds has been used to infer depositional environment and lithology of crude oil source rock and maturity. Ratios involving dibenzothiophenes (DBT) such as DBT/phenanthrene (Phen) and methyldibenzothiophenes (MDBT)/methylphenanthrenes (MPhen) correlated with other biological markers and were used to classify the oils into different source-related types. Type 1 oils with relatively high (DBT/Phen) and (MDBT/MPhen) ratios show marine carbonate depositional setting. Type 2 oils show low (DBT/Phen) and (MDBT/MPhen) ratios and other biomarker features consistent with marine siliciclastic source rocks. On the other hand, type 3 oils have geochemical characteristics intermediate between those of types 1 and 2.     

Study of Crack Propagation in PMMA Using Ultrasonic Technique

Attenuation of ultrasonic waves was measured in different notched specimens of Poly(methylmethacrylate) (PMMA) at different points of crack propagation path. Crack propagation takes place when specimens, with initial single edge notch produced using sharp milling cutter, are subjected to different crosshead speeds of a tensile testing machine. These measurements were performed on specimens having different thicknesses by using pulse echo technique at different frequencies. Attenuation measurements results were confirmed by microscopic images.

The present study showed that attenuation increases when crack propagation speed increases as a result of an increment of crosshead speed of the applied load. Such relation is not affected by the specimens' thickness. The resulting attenuation curves elucidated the neck zone of the crack.     

Vulcanization of Nitrile Rubber. Part III. Formulation and Study of Oil-Resisting Vulcanization,Based on Acrylonitrile-Butadiene Rubber

Acrylonitrile butadiene rubber (Krynac, 803) with the best system of vulcanization in presence of accelerators, and coaccelerators, is further modified by the addition of different quantities of melamine-formaldehyde resin. As compared with the blank sample without this resin, the values of optimum cure time and scorch time decrease with the addition of resin. The rate of vulcanization increases and then begins to decrease gradually at higher quantities. Higher values of tensile strength, modulus, and hardness are obtained for vulcanized samples. The elasticity and elongation at break, respectively, remain at 28% and 260% till 3.0 pphr. Even higher quantities of the added resin lead to slight decreases in the studied properties. Better properties were also obtained upon aging in fuel and in hydraulic oil.     

Polymer nanofiber‐templated fabrication and characterization of gallium oxide nanofibers consisting of granular nanoparticles

Gallium oxide (β‐Ga₂O₃) is an interesting semiconductor that has a wide bandgap and can be used as an optoelectronic material in flat‐panel displays, solar energy conversion devices and optical limiters for UV light. However, it is difficult to fabricate and process Ga₂O₃ nanofibers for actual optoelectronic applications. When the excellent processability of polymeric materials is introduced into the inorganic nanofiber fabrication process, this limitation can be easily overcome. The aim of the research reported was to prepare granular Ga₂O₃ nanofibers utilizing an electrospun polyacrylonitrile nanofiber template combined with sol‐gel technology. Ga₂O₃ nanofibers were successfully fabricated by electrospinning a solution of polyacrylonitrile mixed with gallium nitrate and subsequent calcination. The surface and bulk morphologies of the calcined nanofibers investigated using field‐emission scanning electron microscopy and transmission electron microscopy (TEM) indicated that Ga₂O₃ nanofibers were constructed by the fusion of gallium oxide nanoparticles. TEM bright‐field images combined with selected‐area electron diffraction indicated that the average diameter of the Ga₂O₃ nanofibers produced was ca 55 nm and the crystalline structure was β‐Ga₂O₃ with a monoclinic unit cell. Furthermore, the photoluminescence spectrum of the Ga₂O₃ nanofibers exhibited two strong green emission peaks and one UV emission peak. Copyright © 2010 Society of Chemical Industry     

Chemically stable electrospun NiCu nanorods@carbon nanofibers for highly efficient dehydrogenation of ammonia borane

We describe the preparation of bimetallic NiCu nanorods (NRs) incorporated on carbon nanofibers (NFs). The synthesis nanofibers were prepared by low cost and facile technique; electrospinning. Typically, sol–gel consisting of nickel acetate, copper acetate, and poly (vinyl alcohol) was electrospun. Sintering of the electrospun nanofiber mats in argon atmosphere led to partial elimination of the utilized polymer and abnormal decomposition of the metallic acetates to finally produce NiCu nanorods incorporated in carbon nanofibers. The as-obtained nanofibers were characterized by SEM, FE-SEM, XRD, TGA, XPS, TEM, and TEM-EDX standard techniques. The introduced bimetallic nanofibers revealed superior catalytic activity toward hydrogen release from ammonia borane. Also, they showed a good chemical stability due to covering the bimetallic nanorods by carbon shells. Interestingly, nanofibers were reused for 6 successive cycles with good catalytic activity. Moreover, the prepared nanofibers showed low activation energy about 28.9 kJ/mol. Finally, development of new catalytic materials in the field of energy is considered as a key objective of the modern research.     

Corrosion Inhibition of Mild Steel in Aqueous Solution Containing H2S by some Thiosemicarbozone Compounds

The Electrochemical behavior of mild steel in 3% NaCl is still the objective of many studies which include the investigations of natural and synthetic compounds as inhibitors. In this paper, some derivatives of thiosemicarbazone compound were investigated as inhibitors in medium of 3% NaCl for the mild steel samples. The galvanostatic technique was used in this study to characterize both cathodic and anodic behaviour of mild steel. the percent of inhibition P.I. was calculated for each of thiosemicarbazone compounds in order to determine the effectiveness of these undertesting compounds. As estimated the P.I. was increased with the concentration of each of undertesting compound. In addition the mild steel was tested in 3% NaCl in presence of H₂S. So the synergistic effect of each inhibitor manifests itself for the tested compounds. It was found that the change of the methoxy group position has an active role in the inhibition effect of the tested compound. From others side the introduction of chloro group has also a beneficial inhibition effect.