The Use of Reaction Kinetics in Classifying Alkali Silica Reactivity Potential of Aggregates

The Australian Standard accelerated mortar bar test (AMBT) method, AS 1141.60.1, adopts the expansion limits at two exposure periods to classify the alkali silica reactivity (ASR) of aggregate. This was a first step toward the use of ‘reaction kinetics’ or ‘rate of reaction’ to detect and classify alkali silica reactivity. The AS 1141.60.2 concrete prism test (CPT), on the other hand, uses a single expansion limit at one year to classify ASR. This paper examines the validity of the use of reaction kinetics, evaluated from the AMBT expansion data, to gauge and classify the reactivity. This may enable a better quantification of the degrees of reactivity and a more fundamental approach to ASR mitigatio

Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke

Background Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared the efficacy and safety of two antiplatelet regimens — aspirin plus extendedrelease dipyridamole (ASA–ERDP) versus clopidogrel. Methods In this double-blind, 2-by-2 factorial trial, we randomly assigned patients to receive 25 mg of aspirin plus 200 mg of extended-release dipyridamole twice daily or to receive 75 mg of clopidogrel daily. The primary outcome was first recurrence of stroke. The secondary outcome was a composite of stroke, myocardial infarction, or death from vascular causes. Sequential statistical testing of noninferiority (margin of 1.075), followed by superiority testing, was planned. Results A total of 20,332 patients were followed for a mean of 2.5 years. Recurrent stroke occurred in 916 patients (9.0%) receiving ASA–ERDP and in 898 patients (8.8%) receiving clopidogrel (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11). The secondary outcome occurred in 1333 patients (13.1%) in each group (hazard ratio for ASA–ERDP, 0.99; 95% CI, 0.92 to 1.07). There were more major hemorrhagic events among ASA–ERDP recipients (419 [4.1%]) than among clopidogrel recipients (365 [3.6%]) (hazard ratio, 1.15; 95% CI, 1.00 to 1.32), including intracranial hemorrhage (hazard ratio, 1.42; 95% CI, 1.11 to 1.83). The net risk of recurrent stroke or major hemorrhagic event was similar in the two groups (1194 ASA–ERDP recipients [11.7%], vs. 1156 clopidogrel recipients [11.4%]; hazard ratio, 1.03; 95% CI, 0.95 to 1.11). Conclusions The trial did not meet the predefined criteria for noninferiority but showed similar rates of recurrent stroke with ASA–ERDP and with clopidogrel. There is no evidence that either of the two treatments was superior to the other in the prevention of recurrent stroke. (ClinicalTrials.gov number, NCT00153062.

Análise da adoção de sistemas de rastreabilidade bovina no Brasil: estudos de caso nos segmentos de produção, indústria e comércio.

O Sistema Brasileiro de Identificação e Certificação de Origem Bovina e Bubalina, o SISBOV, completou no início de 2006 quatro anos de existência. Criado principalmente como uma resposta às exigências européias, o SISBOV já passou por uma série de ajustes e modificações em sua estrutura de funcionamento. A partir da análise de estudos de caso envolvendo bovinocultores de corte e leite, bubalinocultores, frigoríficos e empresas de comércio varejista, o presente trabalho tece um panorama sobre a implementação da rastreabilidade na produção brasileira de bovinos, verificando, por exemplo, que o sistema ainda apresenta problemas, sendo pouco adotado por médios e pequenos produtores, principalmente da atividade leiteira. O resultado da pesquisa ressalta ainda que a rastreabilidade e a certificação de origem são usadas com pelo menos cinco propósitos diferentes: como requisitos à exportação, como ferramentas para melhoria da qualidade do produto, como estratégias de diferenciação do produto, como instrumentos para a gestão dos rebanhos ou ainda como suporte à coordenação da cadeia produtiv

Mothers' beliefs about children's learning in Hong Kong and the United States: Implications for mothers' child-based worth

Chinese and American mothers’ beliefs about children’s learning and parents’ role in it were examined using notions salient in Chinese culture. Mothers from Hong Kong (n = 66) and the United States (n = 69) indicated their endorsement of the ideas that children’s learning reflects children’s morality, and parents’ support of children’s learning reflects parents’ love and duty. Mothers also reported on the extent to which their worth is based on children’s performance. Chinese (vs. American) mothers believed more that children’s learning reflects morality and parents’ support of children’s learning reflects love; these differences accounted for their feelings of worth being more dependent on children’s performance. Chinese (vs. American) mothers believed less that parents’ support is a duty.postprin

Express method for isolation of ready-to-use 3D chitin scaffolds from aplysina archeri (aplysineidae: verongiida) demosponge

Sponges are a valuable source of natural compounds and biomaterials for many biotechnological applications. Marine sponges belonging to the order Verongiida are known to contain both chitin and biologically active bromotyrosines. Aplysina archeri (Aplysineidae: Verongiida) is well known to contain bromotyrosines with relevant bioactivity against human and animal diseases. The aim of this study was to develop an express method for the production of naturally prefabricated 3D chitin and bromotyrosine-containing extracts simultaneously. This new method is based on microwave irradiation (MWI) together with stepwise treatment using 1% sodium hydroxide, 20% acetic acid, and 30% hydrogen peroxide. This approach, which takes up to 1 h, made it possible to isolate chitin from the tube-like skeleton of A. archeri and to demonstrate the presence of this biopolymer in this sponge for the first time. Additionally, this procedure does not deacetylate chitin to chitosan and enables the recovery of ready-to-use 3D chitin scaffolds without destruction of the unique tube-like fibrous interconnected structure of the isolated biomaterial. Furthermore, these mechanically stressed fibers still have the capacity for saturation with water, methylene blue dye, crude oil, and blood, which is necessary for the application of such renewable 3D chitinous centimeter-sized scaffolds in diverse technological and biomedical fields. © 2019 by the authors

Interface Phonons and Polaron Effect in Quantum Wires

The theory of large radius polaron in the quantum wire is developed. The interaction of charge particles with interface optical phonons as well as with optical phonons localized in the quantum wire is taken into account. The interface phonon contribution is shown to be dominant for narrow quantum wires. The wave functions and polaron binding energy are found. It is determined that polaron binding energy depends on the electron mass inside the wire and on the polarization properties of the barrier material