Low-frequency conductivity of low wear high-entropy alloys.

High-entropy alloys (HEAs) provide new research avenues for alloy combinations in the periodic table, opening numerous possibilities in novel-alloy applications. However, their electrical characteristics have been relatively underexplored. The challenge in establishing an HEA electrical conductivity model lies in the changes in electronic characteristics caused by lattice distortion and complexity of nanostructures. Here we show a low-frequency electrical conductivity model for the Nb-Mo-Ta-W HEA system. The cocktail effect is found to explain trends in electrical-conductivity changes in HEAs, while the magnitude of the reduction is understood by the calculated plasma frequency, free electron density, and measured relaxation time by terahertz spectroscopy. As a result, the refractory HEA Nb15Mo35Ta15W35 thin film exhibits both high hardness and excellent conductivity. This combination of Nb15Mo35Ta15W35 makes it suitable for applications in atomic force microscopy probe coating, significantly improving their wear resistance and atomic-scale image resolution.

Comparing the rubella seronegativity in pregnant women who received one dose of rubella vaccine at different ages in Taiwan.

INTRODUCTION: Vaccination is the best strategy to prevent rubella and congenital rubella. The aim of our study was to assess the immunity to rubella and determine rubella virus antibody titers in pregnant women who were offered a single dose of rubella vaccine at different ages of their lives. METHODS: A total 15,067 rubella IgG antibody test results for Taiwanese pregnant women who received routine prenatal checkup at Fooyin University Hospital from 1999 to 2014 were analyzed in this study. The women were divided into five birth cohorts in order to compare their rubella seronegativities and antibody titers according to the different period of rubella vaccination policy in Taiwan. RESULTS: The total rubella seronegativity rate was 11.2% (95% CI: 10.7-11.7%) and the mean rubella antibody titers was 51.0IU/mL (SD=54.7IU/mL). The junior school cohort has the lowest rubella seronegativity of 7.6% (95% CI: 6.9-8.2%). The seronegativities were significantly high in the preschool cohort and in the 15-month-old cohort, 14.9% (95% CI: 13.2-16.6%) and 14.8% (95% CI: 11.5-18.1%), respectively. The OR values were 2.1 (95% CI: 1.8-2.5, p<0.001) in the preschool cohort and 2.2 (95% CI: 1.6-2.8, p<0.001) in the 15-month-old cohort, respectively, against the junior school cohort. Women in the 15-month-old cohort have lowest average rubella IgG titer, 25.4IU/mL. CONCLUSION: The total rubella seronegativity rate was 11.2% in all native pregnant women. Women who received one dose rubella vaccine at preschool and 15-month-old have highest seronegativities. The 15-month-old cohort has the lowest average rubella IgG titer. We recommend a revised catch-up immunization policy to women who received one dose rubella vaccine at a younger age.

Aspect-oriented design and implementation of adaptable access control for electronic medical records.

OBJECTIVES: Maintaining proper access control to Electronic Medical Records (EMR) is essential to protecting patients' privacy. We aim to develop mechanisms and tools that can support fine-grained and adaptable access control for EMR. METHOD: This paper presents an aspect-oriented design and implementation scheme to providing adaptable access control for Web-based EMR systems. In our scheme, access control logic is decoupled from the core of the EMR application and collected into separate aspect modules which are automatically synthesized from access control rules in XML format and properly designed aspect templates. The generated aspect modules will then be compiled and integrated into the underlying EMR application using standard aspect tools. At runtime, these binary aspect modules will be executed to enforce the required access control. Future changes of access control rules can also be effectively realized through these mechanisms without actual coding. RESULTS: A structured form of access control rules based on the Taiwan Electronic Medical Record Template, a suite of abstract aspects and templates for enforcing access control and a translator for synthesizing the complete access control code in AspectJ from such access control rules and aspect templates. We have also built a Web-based EMR prototype implementation to demonstrate our approach. CONCLUSION: Our approach can not only accommodate a wide range of fine-grained access control requirements but also enforce them in a modular and easy to adapt manner without incurring extra performance overhead due to rule interpretation. The use of aspect-oriented technology to provide adaptable access control for EMR is a promising approach. We have further enhanced our scheme with a mechanism for dynamic adjustment of access control rules. Other tools for authoring and analyzing the access control rules are the main parts of our future work.

Synthesis of iminoalditol and N-alkyl iminoalditol derivatives of ribopyranosides.

Iminoalditol analogs of ribopyranosides were prepared by reduction of a vinylogous urethane intermediate formed from methyl 2-C-(5-O-methanesulfonyl-beta-d-ribofuranosyl)acetate (1) by treatment with sodium azide in DMF at reflux. The N-alkylated analogs were synthesized either by N-alkylation of the corresponding parent iminoaldithol or, more efficiently, from the product of the reaction of 1 with various alkylamines. The latter process involves an S(N)2 substitution at C-5 by the amine followed by an intramolecular hetero-Michael reaction under basic conditions. The 'aglycon' of the iminoalditol was also modified through amidation and esterification.