2,178 research outputs found
Thiourea Derivative of 2-[(1 R)-1-Aminoethyl]phenol: A Flexible Pocket-like Chiral Solvating Agent (CSA) for the Enantiodifferentiation of Amino Acid Derivatives by NMR Spectroscopy
Thiourea derivatives of 2-[(1R)-1-aminoethyl]phenol, (1S,2R)-1-amino-2,3-dihydro-1H-inden-2-ol, (1R,2R)-(1S,2R)-1-amino-2,3-dihydro-1H-inden-2-ol, and (R)-1-phenylethanamine have been compared as chiral solvating agents (CSAs) for the enantiodiscrimination of derivatized amino acids using nuclear magnetic resonance (NMR) spectroscopy. Thiourea derivative, prepared by reacting 2-[(1R)-1-aminoethyl]phenol with benzoyl isothiocyanate, constitutes an effective CSA for the enantiodiscrimination of N-3,5-dinitrobenzoyl (DNB) derivatives of amino acids with free or derivatized carboxyl functions. A base additive 1,4-diazabicyclo[2.2.2]octane(DABCO)/N,N-dimethylpyridin-4-amine (DMAP)/NBu4OH) is required both to solubilize amino acid derivatives with free carboxyl groups in CDCl3 and to mediate their interaction with the chiral auxiliary to attain efficient differentiation of the NMR signals of enantiomeric substrates. For ternary systems CSA/substrate/DABCO, the chiral discrimination mechanism has been ascertained through the NMR determination of complexation stoichiometry, association constants, and stereochemical features of the diastereomeric solvates
Anharmonicity and self-similarity of the free energy landscape of protein G
The near-native free energy landscape of protein G is investigated through
0.4 microseconds-long atomistic molecular dynamics simulations in explicit
solvent. A theoretical and computational framework is used to assess the
time-dependence of salient thermodynamical features. While the quasi-harmonic
character of the free energy is found to degrade in a few ns, the slow modes
display a very mild dependence on the trajectory duration. This property
originates from a striking self-similarity of the free energy landscape
embodied by the consistency of the principal directions of the local minima,
where the system dwells for several ns, and of the virtual jumps connecting
them.Comment: revtex, 6 pages, 5 figure
Pandemic Data Quality Modelling: A Bayesian Approach = Modellazione della qualit`a dei dati pandemici: un approccio bayesiano
When dealing with pandemics like COVID-19, it is crucial for policymakers to constantly monitor the emergency. Correct data reporting is a hard task during pandemics, and errors affect the overall mortality, resulting in excess deaths in official statistics. In this work, we provide tools for evaluating the quality of pandemic mortality data. We accomplish this through a spatio-temporal Bayesian approach accounting for the bias implicitly contained in the data
Continuum model for polymers with finite thickness
We consider the continuum limit of a recently-introduced model for
discretized thick polymers, or tubes. We address both analytically and
numerically how the polymer thickness influences the decay of tangent-tangent
correlations and find how the persistence length scales with the thickness and
the torsional rigidity of the tube centerline. At variance with the worm-like
chain model, the phase diagram that we obtain for a continuous tube is richer;
in particular, for a given polymer thickness there exists a threshold value for
the centerline torsional rigidity separating a simple exponential decay of the
tangent-tangent correlation from an oscillatory one.Comment: 8 pages, 4 figures. Accepted for publication in J. Phys.
Effectiveness of occupational safety and health training for migrant farmworkers: a scoping review
Objectives: Migrant farmworkers report higher rates of work-related illnesses, injuries and fatalities compared with local workers. Language and cultural barriers represent a relevant source of risk, which can be reduced by means of targeted training interventions. However, very little evidence is available about the effectiveness of Occupational Safety and Health (OSH) training programmes addressing migrant farmworkers. Study design: We carried out a scoping review. Methods: Currently available literature about the effectiveness of OSH training for migrant farmworkers--in terms of improvements in at least one of the following: safety knowledge, behaviours, attitudes and beliefs and health outcomes--was searched from four databases: PubMed, PsycINFO, Scopus and Web of Science. The screening was performed independently by two authors, and any disagreement was resolved through discussion until consensus was achieved. Once the articles eligible for inclusion were selected, the objectives, design, sample and setting, interventions and findings of each study were recorded. No quality assessment tool for publications considered by this study has been used because a scoping review does not aim for critical appraisal. Results: Twenty-nine publications met the inclusion criteria. Of these, nine cross-sectional studies discussed the effectiveness of training activities in terms of whether participating in any programme had or did not have a significant effect on the dependent variables, when training was considered along with other sociodemographic factors. In the majority of these studies, training appeared to have low or no effect on the dependent variables considered. Twenty mainly within-subject experimental studies addressed the effectiveness of specific training methods, reporting significant improvements especially for interventions based on a participatory approach. Conclusions: Training could greatly contribute to an effective attainment of OSH information, but the present review shows that more evidence is needed to guide the future development of effective training activities
Comprehension of Safety Pictograms Affixed to Agricultural Machinery among Pakistani Migrant Farmworkers in Italy
Conveying safety messages on agricultural machinery: The comprehension of safety pictorials in a group of migrant farmworkers in Italy
The comprehension of safety signs affixed to agricultural machinery is fundamental to warning users about the residual risks which cannot be eliminated with machinery design and the adoption of protections. This is particularly relevant for the migrant workforce, which may encounter some language barriers with written safety communication. The present study aimed to investigate the comprehension of safety signs affixed to agricultural machinery in a group of migrants from both European and non-European countries employed in Italian agriculture. Thirty-seven migrant farmworkers (12 Indians, 17 Pakistanis, and eight Romanians) were individually interviewed to test the comprehension of four safety signs referring to the main causes of fatal and non-fatal injuries caused by interactions with farm machinery. Romanians obtained the highest comprehension performance (68.8% of correct answers), followed by Indians (35.4%), with Pakistanis being last (32.4%). The nationality and the previous experience as a farmworker significantly affected the comprehension of safety signs. The results pointed out the importance of adequately training migrants on the meaning of safety signs. Beside this, the study suggests a redesign of the signs, considering some signs' features to enhance pictorials' cross-cultural comprehension
An Easy Route to Enantiomerically Enriched 7- and 8-Hydroxystearic Acids by Olefin Metathesis - Based Approach
The synthesis of enantiomerically enriched 7- and 8-hydroxystearic acids (7- and 8-HSA) has been successfully accomplished starting from chiral non racemic 1-pentadecen-4-ol and 1-tetradecen-4-ol respectively. Their Yamaguchi\u2019s esterification with 4-pentenoic and 5-hexenoic acids respectively afforded the suitable dienic esters which were submitted to ring closing metathesis reaction. After hydrogenation and basic hydrolysis of the complex reaction mixture, chiral non racemic 7- and 8-HSA were obtained in about 40% total yield
Modeling provincial Covid-19 epidemic data in Italy using an adjusted time-dependent SIRD model
In this paper we develop a predictive model for the spread of COVID-19 infection at a provincial (i.e. EU NUTS-3) level in Italy by using official data from the Italian Ministry of Health integrated with data extracted from daily official press conferences of regional authorities and from local newspaper websites. This integration is mainly concerned with COVID-19 cause specific death data which are not available at NUTS-3 level from open official data data channels. An adjusted time-dependent SIRD model is used to predict the behavior of the epidemic, specifically the number of susceptible, infected, deceased and recovered people. Predictive model performance is evaluated using comparison with real data
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