9,684 research outputs found

    Analysis of Mono-, Di- and Oligosaccharides by CE Using a Two-Stage Derivatization Method and LIF Detection.

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    A sensitive CE with LIF method has been developed for quantitative analysis of small carbohydrates. In this work, 17 carbohydrates including mono-, di- and oligosaccharides were simultaneously derivatized with 4-fluoro 7-nitrobenzo furazane (NBD-F) via a twostep reaction involving reductive amination with ammonia followed by condensation with NBD-F. Under the optimized derivatization conditions all carbo-hydrates were successfully derivatized within 2.5 h and separated within 15 min using borate buffer (90 mmol/L, pH 9.2). For sugar standards LODs were in the range of 49.7 to 243.6 nmol/L. Migration time and peak area reproducibility were better than RSD 0.1 and 3%, respectively. The method was applied to measure sugars in nanoliter volume samples of phloem sap obtained by stylectomy from wheat and to honeydew samples obtained from aphids feeding from wheat and willow

    PBP4: A New Perspective on Staphylococcus aureus β-Lactam Resistance.

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    β-lactam antibiotics are excellent drugs for treatment of staphylococcal infections, due to their superior efficacy and safety compared to other drugs. Effectiveness of β-lactams is severely compromised due to resistance, which is widespread among clinical strains of Staphylococcus aureus. β-lactams inhibit bacterial cells by binding to penicillin binding proteins (PBPs), which perform the penultimate steps of bacterial cell wall synthesis. Among PBPs of S. aureus, PBP2a has received the most attention for the past several decades due to its preeminent role in conferring both high-level and broad-spectrum resistance to the entire class of β-lactam drugs. Studies on PBP2a have thus unraveled incredible details of its mechanism of action. We have recently identified that an uncanonical, low molecular weight PBP of S. aureus, PBP4, can also provide high-level and broad-spectrum resistance to the entire class of β-lactam drugs at a level similar to that of PBP2a. The role of PBP4 has typically been considered not so important for β-lactam resistance of S. aureus, and as a result its mode of action remains largely unknown. In this article, we review our current knowledge of PBP4 mediating β-lactam resistance in S. aureus

    Asian Americans respond less favorably to excitement (vs. calm)-focused physicians compared to European Americans

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    OBJECTIVES: Despite being considered a model minority, Asian Americans report worse health care encounters than do European Americans. This may be due to affective mismatches between Asian American patients and their European American physicians. We predicted that because Asian Americans value excitement (vs. calm) less than European Americans, they will respond less favorably to excitement-focused (vs. calm) physicians. METHOD: In Study 1, 198 European American, Chinese American, and Hong Kong Chinese community adults read a medical scenario and indicated their preference for an excitement-focused versus calm-focused physician. In Study 2, 81 European American and Asian American community college students listened to recommendations made by an excitement-focused or calm-focused physician in a video, and later attempted to recall the recommendations. In Study 3, 101 European American and Asian American middle-aged and older adults had multiple online encounters with an excitement-focused or calm-focused physician and then evaluated their physicians\u27 trustworthiness, competence, and knowledge. RESULTS: As predicted, Hong Kong Chinese preferred excitement-focused physicians less than European Americans, with Chinese Americans falling in the middle (Study 1). Similarly, Asian Americans remembered health information delivered by an excitement-focused physician less well than did European Americans (Study 2). Finally, Asian Americans evaluated an excitement-focused physician less positively than did European Americans (Study 3). CONCLUSIONS: These findings suggest that while physicians who promote and emphasize excitement states may be effective with European Americans, they may be less so with Asian Americans and other ethnic minorities who value different affective states

    Sex-specific lifespan and its evolution in nematodes

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    Differences between sexes of the same species in lifespan and aging rate are widespread. While the proximal and evolutionary causes of aging are well researched, the factors that contribute to sex differences in these traits have been less studied. The striking diversity of nematodes provides ample opportunity to study variation in sex-specific lifespan patterns associated with shifts in life history and mating strategy. Although the plasticity of these sex differences will make it challenging to generalize from invertebrate to vertebrate systems, studies in nematodes have enabled empirical evaluation of predictions regarding the evolution of lifespan. These studies have highlighted how natural and sexual selection can generate divergent patterns of lifespan if the sexes are subject to different rates or sources of mortality, or if trade-offs between complex traits and longevity are resolved differently in each sex. Here, we integrate evidence derived mainly from nematodes that addresses the molecular and evolutionary basis of sex-specific aging and lifespan. Ultimately, we hope to generate a clearer picture of current knowledge in this area, and also highlight the limitations of our understanding

    Personal data broker instead of blockchain for students’ data privacy assurance

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    Data logs about learning activities are being recorded at a growing pace due to the adoption and evolution of educational technologies (Edtech). Data analytics has entered the field of education under the name of learning analytics. Data analytics can provide insights that can be used to enhance learning activities for educational stakeholders, as well as helping online learning applications providers to enhance their services. However, despite the goodwill in the use of Edtech, some service providers use it as a means to collect private data about the students for their own interests and benefits. This is showcased in recent cases seen in media of bad use of students’ personal information. This growth in cases is due to the recent tightening in data privacy regulations, especially in the EU. The students or their parents should be the owners of the information about them and their learning activities online. Thus they should have the right tools to control how their information is accessed and for what purposes. Currently, there is no technological solution to prevent leaks or the misuse of data about the students or their activity. It seems appropriate to try to solve it from an automation technology perspective. In this paper, we consider the use of Blockchain technologies as a possible basis for a solution to this problem. Our analysis indicates that the Blockchain is not a suitable solution. Finally, we propose a cloud-based solution with a central personal point of management that we have called Personal Data Broker.Peer ReviewedPostprint (author's final draft
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