A convenient procedure for the preparation of chiral 1,2-aminoalcohols starting from levoglucosenone, a biomass derivative, is described. The 1,2-aminoalcohols, bearing primary, secondary, and ...tertiary amino groups, were tested as chiral catalysts in the asymmetric addition of diethyl zinc to benzaldehyde.
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A synthetic strategy has been developed for the preparation of immobilized 1,2-aminoalcohols starting from easily available and renewable chiral building blocks. They were tested as ...chiral ligands for the asymmetric diethylzinc addition to carbonyl compounds. Enantioselectivities were comparable to those observed for non-immobilized analogs. These results provide strong evidence for the flexibility of our approach to generate highly valuable supported chiral ligands derived from cellulose-rich materials.
In order to determine radiostrontium with a satisfactory chemical yield, calculated by an external standard, and a low level of MDC a radioanalytical method has been optimized, for environmental and ...biological samples. Samples were mineralized and extracted by chromatography with prepackaged columns for Cherenkov effect measurement, via daughter radionuclide
90
Y, generated by
90
Sr. When also
89
Sr is present,
90
Y is eluted by the same column to subtract its contribution to total Cherenkov counts and determine separately
89
Sr and
90
Sr (via
90
Y) activity. By a fitting experimental data with an exponential equation the eventual presence of other β-emitter radionuclides was ascertained.
Abstract The effects of hexavalent chromium on mitochondria of normal human fibroblasts were investigated through the measurement of oxygen consumption, and its genotoxic effect through the analysis ...of chromium DNA adducts and oxidative DNA lesions. ROS production was also quantified. Chromium diminished oxygen consumption by cells in a concentration-dependent manner (IC50 = 66 ± 8 μM). This effect can be attributed to an alteration in mitochondrial functions, leading to defective glucose catabolism. The Comet assay, performed with and without the lesion-specific enzyme formamidopyrimidine–DNA glycosylase (Fpg), highlighted the extent of oxidative DNA base damage. DNA base damage was induced with low concentrations (0.5–3 μM) of Cr(VI), whereas bioenergetic disturbance was only observed at higher concentrations (20–500 μM).
Objective
To evaluate the validity and reliability of the Job Factors Questionnaire, and the influence of gender, academic level and pain/discomfort on dental students’ perception regarding risk ...factors of musculoskeletal disorders.
Methods
One hundred forty‐five dental students from Stony Brook School of Dental Medicine participated voluntarily in this study. The survey was organised in two sections: (i) Job Factors Questionnaire with 15 items that evaluated students’ perceptions about job/study environmental risk factors and their potential contribution to musculoskeletal disorders. The tri‐factorial structure (repetitiveness, work posture and external factors) was used; (ii) Part of the Nordic Questionnaire with questions referring to 9 body areas: Neck, shoulders, upper back, elbows, lower back, wrists/hands, hips, knees and ankles/feet. Students answered if they have had a job‐related pain/discomfort in any of these body areas in the previous 12 months. The data were evaluated statistically by confirmatory factor analysis, convergent and discriminant validities, internal consistency and Z‐test (α = .05).
Results
The tri‐factorial structure was considered valid and reliable for the sample after excluding item 8 and inserting correlations between items 11 and 12, and between 14 and 15. The academic level presented a significant effect on the factors “Work Posture” (P = .02) and “External Factors” (P = .01). Most of the students reported pain in their neck (73.79%), lower back (62.06%) and shoulders (53.10%) in the previous 12 months.
Conclusion
The Work Posture and External Factors were influenced only by academic level. The lower the students’ academic level, the higher their perception for both factors of musculoskeletal disorders.
Abstract Aim: Military personnel needs to develop and maintain the ability to perform specific mechanical actions, under the risk of not fulfilling their assignments and failing in their missions. ...Considering the importance of being able to evaluate whether the military is ready for their jobs, studies have been conducted to establish assessments based on the requirements of the tasks performed in combat, referred to as Combat Tasks (CTs), giving rise to Simulated Tasks (STs). This study aimed to understand how physical STs have been used among military personnel worldwide. Methods: A systematic review was conducted to identify literature published between 2001 and 2021 that investigated STs. The search criteria for articles (keywords, inclusion, and exclusion) were applied to five databases - PubMed, Cochrane, Embase, Scopus, and Web of Science - and the PRISMA recommendations were followed. Results: The searches resulted in 2630 documents, in addition to two studies that came from other sources. After the removal of duplicates, 1216 studies were screened by title and abstract, resulting in 71 documents, which were read in full. In the end, 17 studies were selected for the qualitative analysis. Conclusion: From the data obtained, the results highlighted that six countries with well-structured Armed Forces have been investing in research to develop physical assessments based on CTs, showing a paradigm break regarding conventional physical tests, which ultimately prove to be adequate to measure general fitness levels and issues related to health, but are not sufficient to ensure readiness for the performance of specific military activities.
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