Search results for "LAB"
showing 10 items of 7932 documents
Comparison between the shifted-Laplacian preconditioning and the controllability methods for computational acoustics
2010
Processes that can be modelled with numerical calculations of acoustic pressure fields include medical and industrial ultrasound, echo sounding, and environmental noise. We present two methods for making these calculations based on Helmholtz equation. The first method is based directly on the complex-valued Helmholtz equation and an algebraic multigrid approximation of the discretized shifted-Laplacian operator; i.e. the damped Helmholtz operator as a preconditioner. The second approach returns to a transient wave equation, and finds the time-periodic solution using a controllability technique. We concentrate on acoustic problems, but our methods can be used for other types of Helmholtz pro…
A multifunctional bioconjugate module for versatile photoaffinity labeling and click chemistry of RNA
2011
A multifunctional reagent based on a coumarin scaffold was developed for derivatization of naive RNA. The alkylating agent N3BC [7-azido-4-(bromomethyl)coumarin], obtained by Pechmann condensation, is selective for uridine. N3BC and its RNA conjugates are pre-fluorophores which permits controlled modular and stepwise RNA derivatization. The success of RNA alkylation by N3BC can be monitored by photolysis of the azido moiety, which generates a coumarin fluorophore that can be excited with UV light of 320 nm. The azidocoumarin-modified RNA can be flexibly employed in structure-function studies. Versatile applications include direct use in photo-crosslinking studies to cognate proteins, as dem…
Structure-Function Relationship of Substituted Bromomethylcoumarins in Nucleoside Specificity of RNA Alkylation
2013
Selective alkylation of RNA nucleotides is an important field of RNA biochemistry, e.g. in applications of fluorescent labeling or in structural probing experiments, yet detailed structure-function studies of labeling agents are rare. Here, bromomethylcoumarins as reactive compounds for fluorescent labeling of RNA are developed as an attractive scaffold on which electronic properties can be modulated by varying the substituents. Six different 4-bromomethyl-coumarins of various substitution patterns were tested for nucleotide specificity of RNA alkylation using tRNA from Escherichia coli as substrate. Using semi-quantitative LC-MS/MS analysis, reactions at mildly acidic and slightly alkaline…
Alkylation at the active site of the D-3-hydroxybutyrate dehydrogenase (BDH), a membrane phospholipid-dependent enzyme, by 3-chloroacetyl pyridine ad…
1997
The structure of the rat liver's D-3-hydroxybutyrate dehydrogenase (BDH) active site has been investigated using an affinity alkylating reagent, the 3-chloroacetyl pyridine adenine dinucleotide (3-CAPAD). This NAD+ analogue reagent strongly inactivates the enzyme following a concentration- and time-dependent process with a stoichiometry of approximately 1. The reagent reacts at the coenzyme binding site as revealed by the efficient protection by NADH. The effect of 3-CAPAD is stronger with the enzyme into its natural membrane environment than with the lipid-free purified apoBDH or with the reconstituted apoBDH-mitochondrial phospholipid complex. The pH-dependent effect on the inactivation p…
Considerazioni citotassonomiche e corologiche su Allium chamaespathum Boiss. (Alliaceae) geofita nuova per la flora italiana.
2010
Oggetto di questo studio è una singolare popolazione di Allium a fioritura autunnale, rinvenuta presso Reggio Calabria (Italia meridionale), la quale, per alcune caratteristiche vegetative e fiorali, rientra chiaramente nella sezione Allium. Le piante sono caratterizzate da un habitus robusto, foglie subcilindriche ampiamente fistolose, spata unica, caduca, slargata, con appendice fistolosa, lacerantesi lateralmente, infiorescenza globosa, densa, perianzio cilindrico con tepali conniventi, stami con filamenti laminari, dimorfi, gli esterni semplici e gli interni tricuspidati, e ovario con nettari ben sviluppati. Oltre alla fioritura tardiva (IX-X), gli individui di questa popolazione, prese…
Input of P, N-(phosphanyl, amino)-ferrocene hybrid derivatives in late transition metals catalysis
2018
International audience; Unequally functionalized ferrocenes give access to valuable hemilabile reactivity in catalytic reaction. We address the synthesis of hybrid (P, N)-ferrocenyl compounds for which recent catalytic breakthrough applications have been reported, transversely in late transition metals chemistry. Palladium, nickel, rhodium, iridium, and emerging iron and gold catalysis are illustrated from selected examples, which include CC bond formation from cross-coupling and polymerization, allylic substitution, cyanation, hydroformylation, CH arylation and silylation and hydrogenation reactions.
Fiabilidad y validez de constructo de la traducción al valenciano/catalán del Cuestionario para la Evaluación del Síndrome de Quemarse por el trabajo…
2021
The aim of this study was to evaluate the reliability and construct validity of the Valencian/Catalonian version of the Spanish Burnout Inventory (SBI) in a sample of non-university teachers from the Valencia province (Spain). The sample consisted of 1359 teachers (67.2% were women). This instrument contains 20 items distributed into four dimensions: Enthusiasm toward the job (5 items), Psychological exhaustion (4 items), Indolence (6 items) and Guilt (5 items). The psychometric properties were examined through the following analyses: confirmatory factor analysis (CFA) and reliability (Cronbach’s alpha). All items achieved appropriate values for both statistical and psychometric parameters,…
Studi greci e latini nell?antica Università di Altamura (1748-1821)
2019
The article tries to highlight, despite the scarse of available documentation, the Greek and Latin studies (language and texts) in the ancient Apulian University in Altamura (1748-1821). Furthermore, on the basis of unpublished archival materials (school registers and student workbooks) it is possible to shed light on the ancient authors explained at school, the teaching methods, and the study practices.
The Development of Novel Approaches to the Identification of Chemical and Protein Respiratory Allergens
2008
In October 2006, the European Centre for theValidation of Alternative Methods (ECVAM) spon-sored and hosted a three-day workshop to consideropportunities and challenges in the development ofalternative methods for the identification and char-acterisation of chemical respiratory allergens. Theproceedings, conclusions and recommendations ofthat workshop were subsequently made available asECVAM Workshop Report 60 (1).In April 2008, a second meeting was convenedby ECVAM to consider what progress has beenmade in the light of the recommendations derivedfrom the 2006 Workshop and the publishedreport. This meeting had as a second objective —to consider whether new opportunities for theidentificatio…
Gender and potential wage in Europe: a stochastic frontier approach
2011
PurposeThe purpose of this paper is to provide evidence concerning wage differentials and the existence of gender pay discrimination in France, Germany, Italy, Spain and the United Kingdom.Design/methodology/approachThe authors used the stochastic frontier approach as an alternative method to measure the relevance of gender discrimination. This methodology allows them to explain the differences between the potential and the observed wage that an individual could obtain, given his or her human capital endowment.FindingsThe authors found support for wage discrimination against women. The results show that a significant part of the gender wage gap in all the countries analysed is not attributa…