1,992 research outputs found

    Superconductivity near the vibrational mode instability in MgCNi3

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    To understand the role of electron-phonon interaction in superconducting MgCNi3_{3} we have performed density functional based linear response calculations of its lattice dynamical properties. A large coupling constant λ% \lambda = 1.51 is predicted and contributing phonons are identified as displacements of Ni atoms towards octahedral interstitials of the perovskite lattice. Instabilities found for some vibrational modes emphasize the role of anharmonic effects in resolving experimental controversies.Comment: 4 pages, 4 eps figures, replaces the older versio

    Factors affecting In vitro methane production from cecum contents of White Roman geese

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    The goal of this research was to gain understanding of in vitro methane (CH4) production from the cecal contents of White Roman geese under various incubation conditions. Five experiments were conducted to ascertain the effects of i) incubation time, ii) pH, iii) the addition of formic acid to the culture media, iv) temperature, and v) the addition of salt to the nutritive liquid. Methane production increased significantly with the supplementation of formic acid in the culture fluid (Experiment III). Additionally, CH4 production Experiment V was higher than that without saline. In contrast, low CH4 production occurred under acidic conditions (pH ≩5.4) and at temperatures higher or lower than typical bird body temperature (43 °C) without formic acid and saline solution in the culture media. Since bird body temperature cannot be controlled easily, approaches such as maintaining cecum fluid at low pH and preventing the formation of formic acid by adjusting the recipes of feeds could be considered for controlling in vivo CH4 production from the intestinal tract digesta of geese

    Activation mechanisms of butyrylcholinesterase by 2,4,6-trinitrotoluene, 3,3-dimethylbutyl-N-n-butylcarbamate, and 2-trimethylsilyl-ethyl-N-n-butylcarbamate

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    The goal of this work was to propose a possible mechanism for the butyrylcholinesterase activation by 2,4,6-trinitrotoluene (TNT), 3,3-dimethylbutyl-N-n-butylcarbamate (1), and 2-trimethylsilyl-ethyl-N-n-butylcarbamate (2). Kinetically, TNT, and compounds 1 and 2 were characterized as the nonessential activators of butyrylcholinesterase. TNT, and compounds 1 and 2 were hydrophobic compounds and were proposed to bind to the hydrophobic activator binding site, which was located outside the active site gorge of the enzyme. The conformational change from a normal active site gorge to a more accessible active site gorge of the enzyme was proposed after binding of TNT, and compounds 1 and 2 to the activator binding site of the enzyme. Therefore, TNT, and compounds 1 and 2 may act as the excess of butyrylcholine in the substrate activator for the butyrylcholinesterase catalyzed reactions

    What do they eat? A survey of eat-out habit of university students in Taiwan

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    [EN] Main purpose of this research is trying to understand food likeliness of Taiwan college students, and probe whether these food are healthy. Three survey steps are taken as: step 1, market survey for what kind of foods are selling around the campuses; step 2, questionnaire investigation for students food preference; step 3, analyzing whether these favorite foods are healthy or not. The result shows: major consideration for students food selection are “taste” and “price”; 63% of students are taking food or snacks late at night at least once a week. Top three most favorite foods are: Taiwanese fries (yan su ji), carbon grilled chicken and fried fish steaks. Quantities of these foods are small, prices are low, and easy access from roadside food stands. Problems of them are high calories, easy to accumulate free radical in human body, plus insanitary food processing environment. They are harmful to student health. We suggest Taiwan government take it seriouslyShih, K.; Wang, M.; Shih, H.; Lee, S.; Lin, T. (2020). What do they eat? A survey of eat-out habit of university students in Taiwan. Editorial Universitat Politùcnica de Valùncia. 421-430. https://doi.org/10.4995/INN2019.2019.10562OCS42143

    Differences in the Fine Motor Performance of Children in Hong Kong and the United States on the Bruininks-Oseretsky Test of Motor Proficiency

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    ObjectiveCross-cultural differences in motor development is an important issue for occupational therapists to address in the assessment process. The cultural variability of performance in scores interpretation can mislead therapists in their decisions regarding the need for intervention. This study aimed to investigate the differences in fine motor performance on the Bruininks-Oseretsky Test of Motor Proficiency (BOTMP) between school-aged children of Hong Kong and the United States.MethodsThe four fine motor subtests of the BOTMP were administered to a random sample of 264 Hong Kong children aged 6–10 years. The performance scores of participants were compared with those of the American normative samples.ResultsNo significant difference was found in the scores between the two groups in Upper Limb Coordination and Response Speed subtests. However, the Hong Kong children performed significantly better in the subtests of Visual-Motor Control and Upper Limb Speed and Dexterity. In addition, significant gender difference was also present in all subtest scores except for the subtest of Upper Limb Speed and Dexterity.ConclusionThe results suggest that occupational therapists should be cautious of cross-cultural differences when interpreting fine motor performance scores using the BOTMP for Hong Kong school- aged children

    Benzene-di-N-substituted carbamates as conformationally constrained substrate analogs of cholesterol esterase

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    Benzene-1,2-, 1,3-, and 1,4-di-N-substituted carbamates (1-15) are synthesized as the constrained analogs of gauche, eclipsed, and anti conformations, respectively, for the glycerol backbones of triacylglycerol. Carbamates 1-15 are characterized as the pseudo substrate inhibitors of cholesterol esterase. Long chain carbamates are more potent inhibitors than short chain ones. Comparison of different geometries for benzene-di-substituted carbamates, such as benzene-1,2-di-N-octylcarbamate (3) (ortho-3), benzene-1,3-di-N-octylcarbamate (8) (meta-8), and benzene-1,4-di-N-octylcarbamates (13) (para-13), indicates that inhibitory potencies are as followed: meta-8 > para-13 > ortho-3. Therefore, we suggest that the preferable conformation for the C(sn-1)-O/C(sn-2)-O glycerol backbone in the enzyme-triacylgycerol complex is the eclipsed conformation. Meanwhile, kinetic data indicate that among ortho, meta, and para carbamates, meta carbamates most resemble the substrate cholesterol ester

    Responses of Helicoverpa armigera to tomato plants previously infected by ToMV or damaged by H-Armigera

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    We report the comparative inducing effects of a phytopathogen and a herbivorous arthropod on the performance of an herbivore. Tomato, Lycopersicon esculentum Mill., was used as the test plant, and tomato mosaic virus (ToMV) and corn earworm, Helicoverpa armigera Hubner, were used as the phytopathogen and herbivore, respectively. There were decreases in the efficiency of conversion of ingested food and efficiency of conversion of digested food when H. armigera was reared on tomato plants that had been previously inoculated with ToMV. However, virus inoculation did not affect feeding or oviposition preferences by H. armigera. In contrast, approximate digestibility, total consumption, relative growth rate, and relative consumption rate were lower for fourth-instar H. armigera that fed on plants previously damaged by the same herbivore. Feeding and oviposition were both deterred for H. armigera that fed on previously damaged plants. The duration of development of H. armigera was also prolonged under this treatment. Infection by ToMV and feeding damage by H. armigera increased the host plant's peroxidase and polyphenol oxidase activity, respectively, suggesting that the performance of H. armigera may be affected by the induced phytochemistry of the host plant. Overall, this study indicated that, in general, insect damage has a stronger effect than ToMV infection on plant chemistry and, subsequently, on the performance of H. armigera

    Probing structure-function relationships of serine hydrolases and proteases with carbamate and thiocarbamate inhibitors

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    Benzene-1,3-di-N-n-octylcarbamate (1), benzene-1-hydroxyl-3-N-n-octylcarbamate (2), benzene-1,3-di-N-n-ocztylthiocarbamate (3), and benzene-1-hydroxyl-3-N-n-octylthiocarbamate (4) are synthesized from 1,3-benzene-diol and are characterized as the pseudo-substrate inhibitors of acetylcholinesterase, butyrylcholinesterase, cholesterol esterase, lipase, trypsin, and chymotrypsin. For these six enzyme inhibitions by 1-4, the pK(i) values are linearly correlated with their log k(i) values - Bronsted plots. Therefore, 1-4 inhibit these enzymes through a common mechanism. Moreover, both pK(i) and log k(i) values for the inhibitions by 1,3, and 4 are linearly correlated with both pK(i) and log k(i) values for the inhibitions by 2, respectively. Thus, the pK(i) values for the inhibitions by 2 are defined as the nucleophilicity constants of these enzymes (n(enzyme)). The log k(2) values for the inhibitions by 1-4 are also linearly correlated with the n(enzyme) values. Therefore, the nucleophilicity for serine hydrolases and proteases toward 1-4 also applies the Swain-Scott correlations
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