Histamine receptors in the isolated rat stomach fundus and rabbit aortic strips

The effects of histamine and 4-methylhistamine (a selective H2-agonist) were studied on the isolated rat stomach fundus and rabbit aortic strips superfused with Krebs' solution. The contraction induced by histamine was found to be mediated via mepyramine-sensitive H1, while the relaxation induced by the amine through metiamide-sensitive H2-receptors in both smooth muscles. Prior addition of metiamide to the superfusion medium caused an apparent dose-related potentiation in the response to histamine on the aortic strip but not on the stomach fundus strip. The relaxation produced by histamine on the aortic strip demonstrated when the muscle was pretreated with mepyramine and contracted by angiotensin II or serotonin. Metiamide competitively inhibited the relaxation induced by histamine but not by papaverine in both smooth muscles. 4-Methylhistamine produced only a relaxation in the rat stomach fundus which could be competitively inhibited by metiamide. This analog had no agonistic property in the aortic strip. From these results it was concluded that histamine H1-and H2-receptors are present in both smooth muscles. The predominant contractile effect of histamine is mediated through H1-receptors and the relaxing effect of the amine through H2-receptors.     

Formulation and characterization of formaldehyde cross-linked degradable starch microspheres containing terbutaline sulfate

Preparation of starch microspheres using epichlorohydrin is a time consuming method and requires around 18 hr for cross-linking reaction. To reduce reaction time, terbutaline sulfate (TBS) loaded degradable starch microspheres (DSM) were prepared using formaldehyde as the cross-linking agent. All microspheres were spherical in shape and had a porous, rough surface with a mean particle size of 18-24 microm. Whatever the cross-linking time, it was seen that the release of the TBS was not complete during the release experiments. The influence of enzyme on the degradation of microspheres was moderate. Following intravenous administration, initial uptake of microspheres by the lung was higher than those of other organs.     

Enhanced Morphological Stability in Sb-Doped Ge

The axial heat processing (AHP) crystal growth technique was used to investigate the morphological stability of faceted solid/liquid (s/l) interfaces. Six Sb-doped Ge single crystals containing 2.3 × 10⁻² to 2.3 × 10⁻¹ at. pct Sb were grown at pulling rates of 10 to 20 mm/h. These include two bicrystals specifically designed to investigate the effect of slight misorientation on stability. Faceted growth with a kinetic supercooling on the order of 0.15 K was achieved, and a characteristic two-dimensional W instability boundary, an inverted crater in three dimensions, was observed. The crystals exhibited enhanced morphological stability over the predictions of the constitutional supercooling (CS) criterion and the Mullins and Sekerka (MS) stability criterion, with the highest stability in the center of the W. These results are examined with current analytical stability theories accounting for convection and kinetics. An alternate model is proposed based on anisotropic kinetics and the competition between lateral spreading on a faceted interface and the amplification rate of an interfacial perturbation.

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Isothermal crystallization kinetics of glass fiber and mineral-filled polyamide 6 composites

In this study, isothermal crystallization kinetics of polyamide 6 (PA6) composites reinforced with surface-treated glass fiber (GF) and natural, clay-type mineral (MN) were investigated by differential scanning calorimetry method in the presence and absence of a nucleating agent (NA). Microstructural features of the composites and interfacial interactions between filler and polyamide phases were also quantified by rheological measurements. The kinetic parameters for the isothermal melt-crystallization process of the samples were determined with the Avrami and Lauritzen–Hoffman models. The crystallization activation energies were determined by the Arrhenius method. It was found that the both fillers yielded a significant increase in the storage modulus of PA6. Kinetic calculations showed that the MN has a more pronounced acceleration effect on the crystallization rate of PA6 than the GF. Introduction of a small amount of NA significantly favored the isothermal crystallization rate of GF-reinforced PA6 but did not accelerate that of MN-reinforced one. Based on the results, it has been highlighted that PA6 composites reinforced with surface-treated GFs and including a small amount of clay-like mineral as a cheap and easy-accessible minor filler could yield the best performance for the injection-molded PA6 parts because the GF enhances the mechanical properties and the clay-like mineral accelerates the crystallization rate.     

A quantitative approach for measuring process innovation: a case study in a manufacturing company

Process management and innovation arguably remain among the concepts under focus of recent researches since there is no significantly outstanding method to measure and monitor the level of innovation in the manufacturing processes over a particular time period taking the fundamental activities of manufacturing processes into account. Although there are various studies relevant to process improvement, manufacturing processes are not focused on in the literature. This paper presents a novel performance indicator, called degree of process innovation, for monitoring and measuring innovation in manufacturing processes based on the four most important components among the fundamental activities of a manufacturing system. The components are namely Average Labour Utilisation, Cumulative Bottleneck Ratio, Unit Production Time and Unit Production Cost. The idea behind this approach has flourished on the basis of an indicator proposed in the literature to measure the general organisational improvements. The scope of that indicator has been narrowed down to manufacturing processes to accurately reflect the state of the manufacturing processes. The proposed approach has been verified with a case study in manufacturing industry, where each of the four sub-indicators was calculated based on the data provided and aggregated into the degree of process innovation. The innovation degree is successfully indicated.     

Poly(o-anisidine) on brass: Synthesis and corrosion behavior

The electrochemical synthesis of poly(o-anisidine) (POA) was achieved on brass (CuZn) electrode by applying two scan rates (50 and 20 mVs⁻¹). The synthesized polymer films were strongly adherent and homogeneous in both cases. Their corrosion performance was investigated by AC impedance spectroscopy (EIS) technique, anodic polarization plots and open circuit potential-time curves, in 3.5% NaCl solution. It was clearly seen that poly(o-anisidine) films provided a significant physical protection for longer exposure time. It was shown that polymer film coated at high scan rate (CuZn/POA-H) exhibited better barrier property against the attack of corrosive agents when compared with polymer film obtained at low scan rate (CuZn/POA-L). It was found out that poly(o-anisidine) film synthesized at high scan rate caused a significant increase in corrosion resistance by its catalytic behavior on formation of protective oxide layers on the surface in longer time.