188 research outputs found

    The restorative effect of the environment on organizational cynicism and work engagement

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    The aim of this study is to explore the relationship between restorativeness, work engagement and organizational cynicism. A positive effect of restorativeness on work engagement and a negative effect on organizational cynicism are hypothesized. A self-report questionnaire was filled out by 247 employees. Results of hierarchical linear regression supported a positive effect of restorativeness in reducing both organizational cynicism and in fostering work engagement. The original contribution of this research is the analysis of the multivariate relationship between restorativeness (which is a relevant construct in environmental psychology) and relevant constructs deriving from the work and organizational psychology field (i.e., work engagement and cynicism in the workplace

    On the Chiroptical Behavior of Conjugated Multichromophoric Compounds of a New Pseudoaromatic Class: Bicolchicides and Biisocolchicides

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    It is well known that, stemming from the mutual interplay between chromophores, circular dichroism (CD) is a powerful technique to deal with structural problems for both the small organic molecule and the biopolymer. However, quantitative interpretations of the spectroscopic and structural terms that give rise to the exciton couplet are usually presented for ideal cases, or a few CD bands only are taken into account, overlooking the role of the solvent medium. Circular dichroism and UV absorption spectra were carried out for colchicide (3) and isocolchicide (6), as well as their coupling products, 10,10'-bicolchicide (2) and 9,9'-biisocolchicide (5), in both hydrogen bonding and non hydrogen bonding solvents, as well as MeCN/H(2)O mixtures. A dramatic control by the solvent emerged, as even tiny changes in the composition of solvent mixtures, at ca 1 water molar fraction, induced a dramatic modification of their CD bands. A mutarotation phenomenon--long known for isocolchicine (8)--was also observed for 5, and can be attributed to the interconversion between atropisomers (R(a),7S),(R(a),7'S)-5a and (R(a),7S),(S(a),7'S)-5b. Our data show that with molecules built on two structurally identical moieties which embody both hydrophilic and hydrophobic groups, even tiny changes in the composition of solvent mixtures cause a dramatic modification of the CD bands. Their analysis arrives at a qualitative rationalization of the observed CD couplets from the coupling of high energy transitions, while attempts at a quantitative interpretation of these phenomena through time-dependent density functional theory allowed to reproduce satisfactorily the CD spectrum in the 300-450 nm region only. Failure with higher energies probably reflects currently inadequate specific theoretical treatments of the solvent medium

    A more sustainable membrane preparation using triethyl phosphate as solvent

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    Abstract In this work, hydrophobic poly(vinylidene fluoride) membranes for potential membrane distillation applications, with pore sizes ranging from ~ 0.05 to ~ 0.30 μm, were prepared by employing triethyl phosphate (TEP) as a substitute to the hazardous, commonly used, toxic solvents. Membrane morphologies and properties were tailored based on the main parameters, such as the casting solution composition and the operational conditions, which affect the phase inversion process. Experimental results showed that exposure time to controlled humid air and temperature, as well as additive content in the dope solution, strongly influence the membrane formation. The use of TEP as an alternative solvent may contribute to the development of sustainable separation operations

    STARGATE-X: a Python package for statistical analysis on the REACTOME network

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    Many important aspects of biological knowledge at the molecular level can be represented by pathways. Through their analysis, we gain mechanistic insights and interpret lists of interesting genes from experiments (usually omics and functional genomic experiments). As a result, pathways play a central role in the development of bioinformatics methods and tools for computing predictions from known molecular-level mechanisms. Qualitative as well as quantitative knowledge about pathways can be effectively represented through biochemical networks linking the biochemical reactions and the compounds (e.g., proteins) occurring in the considered pathways. So, repositories providing biochemical networks for known pathways play a central role in bioinformatics and in systems biology. Here we focus on Reactome, a free, comprehensive, and widely used repository for biochemical networks and pathways. In this paper, we: (1) introduce a tool StARGate-X (STatistical Analysis of the Reactome multi-GrAph Through nEtworkX) to carry out an automated analysis of the connectivity properties of Reactome biochemical reaction network and of its biological hierarchy (i.e., cell compartments, namely, the closed parts within the cytosol, usually surrounded by a membrane); the code is freely available at https://github.com/marinoandrea/stargate-x; (2) show the effectiveness of our tool by providing an analysis of the Reactome network, in terms of centrality measures, with respect to in- and out-degree. As an example of usage of StARGate-X, we provide a detailed automated analysis of the Reactome network, in terms of centrality measures. We focus both on the subgraphs induced by single compartments and on the graph whose nodes are the strongly connected components. To the best of our knowledge, this is the first freely available tool that enables automatic analysis of the large biochemical network within Reactome through easy-to-use APIs (Application Programming Interfaces)

    The Effects of the Metal Ion Substitution into the Active Site of Metalloenzymes: A Theoretical Insight on Some Selected Cases

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    A large number of enzymes need a metal ion to express their catalytic activity. Among the different roles that metal ions can play in the catalytic event, the most common are their ability to orient the substrate correctly for the reaction, to exchange electrons in redox reactions, to stabilize negative charges. In many reactions catalyzed by metal ions, they behave like the proton, essentially as Lewis acids but are often more effective than the proton because they can be present at high concentrations at neutral pH. In an attempt to adapt to drastic environmental conditions, enzymes can take advantage of the presence of many metal species in addition to those defined as native and still be active. In fact, today we know enzymes that contain essential bulk, trace, and ultra-trace elements. In this work, we report theoretical results obtained for three different enzymes each of which contains different metal ions, trying to highlight any differences in their working mechanism as a function of the replacement of the metal center at the active site

    Low dose infliximab for prevention of postoperative recurrence of crohn's disease: Long term follow-up and impact of infliximab trough levels and antibodies to infliximab

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    Objective In patients with postoperative recurrence of Crohn's disease endoscopic and clinical remission can be maintained for up to 1 year with low infliximab doses (3 mg/Kg). However, in theory low-dose infliximab treated patients could develop subtherapeutic trough levels, infiximab antibodies, and might loose response to therapy. To verify this hypothesis infliximab pharmacokinetics and clinical/endoscopic response were checked in a group of patients treated in the long term with low infliximab doses. Design Infliximab antibodies, infliximab levels, highly-sensitive CRP and fecal calprotectin were measured during the 8-week interval in 5 consecutive patients in clinical (Crohn's Disease Activity Index < 150) and endoscopic (Rutgeerts scores 0-1) remission after one year of therapy with infliximab 3 mg/Kg. For comparison with reported standards, infliximab pharmacokinetics and inflammatory parameters were also tested in 6 Crohn's disease patients who did not undergo surgery and who were in clinical remission while on infliximab 5 mg/ Kg. Patients on low infliximab dose also underwent colonoscopy after 18 additional months of therapy. Results Highly sensitive CRP and fecal calprotectin increased in all patients during the 8-week interval. Infliximab trough levels were lower in patients treated with the low dose compared to controls (mean\ub1SE: 2.0\ub10.3 vs 4.75\ub10.83 \uceg/mL respectively p<0.05). Infliximab antibodies were present in two of the subjects treated with low infliximab dose and in none of the controls. However, in low dose-treated patients after 18 additional months of therapy endoscopy continued to show mucosal remission and none of them developed clinical recurrence or side effects. Conclusions Patients treated with low infliximab doses had lower trough levels compared to patients treated with 5 mg/Kg and some developed antibodies to infliximab. However, low infliximab doses sustained clinical and endoscopic remission for a total of 30 months of treatment

    Bacillus pumilus severe wound infection in a healthy ten years old child: a rare case report

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    Bacillus pumilus is commonly isolated from a wide variety of soils, plants and environmental surfaces, but rarely from human specimens. In this report, we describe a case of infection caused by B. pumilus in a healthy 10-years-old child. The microorganism was recovered from a severe wound of the left knee after three days from trauma. Pathogen identification was carried out by mass spectrometry. The patient's outcome was positive following an ampicillin/sulbactam treatment without complications

    On the Inhibition Mechanism of Glutathione Transferase P1 by Piperlongumine. Insight From Theory

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    Piperlongumine (PL) is an anticancer compound whose activity is related to the inhibition of human glutathione transferase of pi class (GSTP1) overexpressed in cancerous tumors and implicated in the metabolism of electrophilic compounds. In the present work, the inhibition mechanism of hydrolyzed piperlongumine (hPL) has been investigated employing QM and QM/MM levels of theory. The potential energy surfaces (PESs) underline the contributions of Tyr residue close to G site in the catalytic pocket of the enzyme. The proposed mechanism occurs through a one-step process represented by the nucleophilic addition of the glutathione thiol to electrophilic species giving rise to the simultaneous C-S and H-C bonds formation. Both the used methods give barrier heights (19.8 and 21.5 kcal mol−1 at QM/MM and QM, respectively) close to that experimentally measured for the C-S bond formations (23.8 kcal mol−1)

    QM Cluster or QM/MM in Computational Enzymology: The Test Case of LigW-Decarboxylase

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    The catalytic mechanism of the decarboxylation of 5-carboxyvanillate by LigW producing vanillic acid has been studied by using QM cluster and hybrid QM/MM methodologies. In the QM cluster model, the environment of a small QM model is treated with a bulky potential while two QM/MM models studies include partial and full protein with and without explicitly treated water solvent. The studied reaction involves two sequential steps: the protonation of the carbon of the 5-carboxy-vanillate substrate and the decarboxylation of the intermediate from which results deprotonated vanillic acid as product. The structures and energetics obtained by using three structural models and two density functionals are quite consistent to each other. This indicates that the small QM cluster model of the presently considered enzymatic reaction is appropriate enough and the reaction is mainly influenced by the active site

    Participation of the nucleobases in the regioselective backbone fragmentation of nucleic acids. A molecular dynamics and tandem mass spectrometric investigation on a model dinucleoside phosphotriester

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    The anions (I–III) obtained from O-methyl 5′-O-(5′-deoxythymidine) 3′-O-(2′,3′-dideoxyuridine) phosphate by the competitive removal of the 3-N-H protons of the nucleobases and of the methyl group from the phosphotriester bond, assume in the gas phase stable conformations as a function of their charge site. The mass-analyzed ion kinetic energy (MIKE) spectra of I and III show that the regioselective backbone cleavage of the internucleotidic linkage is controlled by the 2′-H proton transfer to the nucleobase within the 5′-end nucleoside. Similar pathways are taken by species II when the nucleobase is eliminated as neutral from the 5′-end nucleoside
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