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In this study, optimum processing conditions for strip-cast AZ31 Mg alloy was investigated on the basis of processing map and microstructural analysis. To obtain the processing map, isothermal compression tests were carried out to a strain of 0.5 at temperatures of 200 ∼ 400°C with the strain rates of 0.01 ∼ 10s-1. It was found that maximum efficiency indicating the optimum processing condition occurred at 300°C and 10s-1. The possible deformation mechanisms operating at high temperature was also discussed.

Efficient development of method for performance evaluation of machine tools has been regarded as the most important issue to enhance accuracy and quality for users and manufacturers. Recently, a method of accuracy evaluation for machine tools has been studied as interests on precision machine tools have rapidly increased. From this point of view, the circular interpolation test of machine tools is recognized as the most useful method to identify the dynamic accuracy of NC machine tools by ISO, ANSI/ASME and others. In this paper, we studied and developed a formal measurement system with a grid encoder to analyze the final accuracy of NC machine tools. We analyzed the servo system error and the geometric error of NC machine tools through measuring the dynamic error signals by using this system. We verified the experimental result and enhanced the reliability by means of comparing the characteristics of the developed system with the kinematical ball-bar system.

Traumatic arteriovenous fistulas following carotid artery injuries are rare. Treatment of carotid artery-to-jugular vein fistula requires direct closure of the fistula or occlusion of the carotid artery above and below the level of the fistula, by a surgical or endovascular approach. A 32-year-old man presented with a right-sided pulsatile neck swelling 2 days following a stab wound. Neck computed tomography demonstrated a vascular mass protruding into the anterior neck. Digital subtraction arteriography demonstrated a bilobular large internal carotid artery pseudoaneurysm just distal to its bifurcation. There was simultaneous opacification of a dilated left internal jugular vein indicating a high-flow internal carotid-internal jugular fistula. A balloon-expandable stent-graft was delivered and successfully positioned across the fistula. The arteriovenous fistula and pseudoaneurysm completely disappeared and the right internal carotid artery was well preserved. The stent-graft is a promising technology to obliterate fistulae and preserve the parent artery with relative safety.

To learn to which portions of a line normal subjects would attend when watching this line actually moving or when perceiving movement even in the absence of actual movement, an illusory movement.

A Monochoria vaginalispopulation that survived after treatment with sulfonylurea herbicide-based mixtures was identified in 1997 in the paddy fields in Chonnam province, Korea. The field had been in monoculture rice production and had been treated with sulfonylurea herbicide-based mixtures for 8 consecutive years. In greenhouse studies, the resistant/wild I50ratios of M. vaginalisto pyrazosulfuron-ethyl were 21.2, 28.5, 23.4, and 12.8 when treated at 2, 7, 14, and 21 days after seeding, respectively. The same trends of I50ratios of 42.4, 17.2, 9.2, and 6.1 were obtained after treatment with bensulfuron-methyl, respectively. The resistant type of M. vaginalisshowed high levels of cross-resistance to pyrazosulfuron-ethyl, bensulfuron-methyl, cyclosulfamuron, and flumetsulam, but not to imazaquin. The resistant type of M. vaginalisdid not show multiple resistance to other herbicides having different modes of action, such as simazine, propanil, oxadiazon, butachlor, and 2,4-D. In vitroacetolactate synthase (ALS) assay showed that the pI50values of bensulfuron-methyl to the wild and resistant type of M. vaginaliswere 9.3 and 7.1. Also, the pI50values of flumetsulam to the wild and resistant type of M. vaginaliswere 7.7 and 6.0 but those of imazaquin were 8.3 and 8.2. Acetolactate accumulation in the resistant type of M. vaginalisplants treated with bensulfuron-methyl or flumetsulam followed by 1,1-cyclopropane dicarboxylic acid were significantly higher than that of wild type. However, the accumulation of acetolactate in the plants treated with imazaquin was not significantly different in the wild and the resistant type of M. vaginalis. In vitroand in vivoALS assay results showed that the resistance mechanism of M. vaginalismight be due to the altered acetolactate synthase.

Biomaterials-based tissue engineering scaffolds play an essential role as an independent therapy or with the combination of cellular or biological active constituents in tissue regeneration applications. However, synthetic grafts, xenografts, and allografts are recognized as foreign materials in human body, resulting in suboptimal clinical outcomes. Recently, autologous materials from a patient's body have drawn great attention in clinical treatment and tissue engineering. Moreover, the autologous scaffolds equipped with the advantages of tissue-like hydrogels have great potential to become a highly versatile tool as personalized hydrogels (PHs) for applications in 3D cell culture and tissue engineering. PHs may feature excellent biocompatibility, tailorable mechanical properties, regenerative capability, non-rejection of grafts/transplants on immunological responses, and customizable properties which could be suitable to meet the personal and clinical care. Here, we present a scoping review of recent progress of PHs with a focus on detailed preparation methods, material properties, and tissue engineering applications along with their challenges and opportunities. It is expected that PHs will circumvent the limitations of current tissue engineering therapies and will be used as next-generation scaffolds for tissue engineering and translational research.

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AbstractThis article introduces a concept for deliberately varying the wall thicknesses of an injection-molded part within prescribed dimensional tolerance to reduce part warpage. The “warpage” described is measured from warpage simulation so as to represent various deformation behaviors of the molded part. Considering the variation in molding process as noise factors, a wall thickness model that minimizes the effect of these noises on warpage characteristics is obtained using the Taguchi method. The warpage characteristics of this model are compared with those of the constant-wall-thickness models that comply the general rule of an uniform wall thickness in part design. Each wall thickness model is then simulated for plausibly small process fluctuations against the best process conditions of each model that would occur in the actual molding operation. It is seen that varying wall thicknesses obtained by the present study exhibits better warpage characteristics in terms of warpage mean and variance against this mean, compared to the constant wall thicknesses.

Purpose: To identify the expression of gonadotropin-releasing hormone (GnRH) messenger ribonuclueic acid (mRNA) and localize GnRH receptors in mature rat and adult human testes. Materials and Methods: In situ hybridization and enzymatic receptor binding localization were performed. Results: GnRH mRNA was expressed within the seminiferous tubules in both mature rat and adult human testis. In rats, expression of GnRH mRNA was identified in the Sertoli cells and spermatogenic cells of some seminiferous tubules, but the other tubules did not express any hybridization signal. In humans, expression of GnRH mRNA was identified only in some spermatogenic cells in some seminiferous tubules. The receptors for GnRH were localized to cells in the interstitial tissues of the testis, probably Leydig cells. Conclusion: The authors believe that the mature rat and adult human seminiferous tubular cells produce GnRH at the same specific stage of the spermatogenic cycle and that GnRH produced within seminiferous tubules, including Sertoli cells and spermatogenic cells, reacts with neighboring GnRH receptors in interstitial cells, including Leydig cells. The GnRH produced from the Sertoli cells in seminiferous tubules would react with GnRH receptors in interstitial cells as a paracrine hormone.

A quantitative, sensitive, and specific GLC method was developed for the determination of pentylenetetrazol in water, plasma, and urine. The assay involves a single extraction of the sample into chloroform followed by centrifugation, evaporation, and chromatography. The method for pentylenetetrazol is reproducible, and the sensitivity limit of the assay is 0.5 μg of pentylene-tetrazol/ml of biological fluid using a 2-ml sample. This method has a sensitivity sufficient to detect human plasma levels after therapeutic clinical doses and was successfully applied to monitor complete plasma level profiles of this drug in dogs. The data indicate that this drug is very rapidly absorbed following an oral dose, and the half-life of the drug in plasma is approximately 1 hr.

The lower critical solution temperature (LCST) properties and hydrolytic behaviour of thermosensitive biodegradable polyphosphazenes with monomethoxy-poly(ethylene glycol), glycine ethyl ester and depsipeptide ethyl esters substituents have been studied. All the polymers synthesized show LCST properties. The LCSTs of the polymers are affected by the composition of the polymers and increase with the degradation of the polymers in aqueous solution. The higher content of depsipeptide ethyl esters in the polymers accelerates the LCST change and the degradation of the polymers in aqueous solution. Most polymers synthesized have half-lives of less than 10 days in neutral solution.© 2002 Society of Chemical Industry