373 research outputs found

    DNA damage among wood workers assessed with the comet assay

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    Exposure to wood dust, a human carcinogen, is common in wood-related industries, and millions of workers are occupationally exposed to wood dust worldwide. The comet assay is a rapid, simple, and sensitive method for determining DNA damage. The objective of this study was to investigate the DNA damage associated with occupational exposure to wood dust using the comet assay (peripheral blood samples) among nonsmoking wood workers (n = 31, furniture and construction workers) and controls (n = 19). DNA damage was greater in the group exposed to composite wood products compared to the group exposed to natural woods and controls (P < 0.001). No difference in DNA damage was observed between workers exposed to natural woods and controls (P = 0.13). Duration of exposure and current dust concentrations had no effect on DNA damage. In future studies, workers' exposures should include cumulative dust concentrations and exposures originating from the binders used in composite wood products

    The future of NMR-based metabolomics

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    The two leading analytical approaches to metabolomics are mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. Although currently overshadowed by MS in terms of numbers of compounds resolved, NMR spectroscopy offers advantages both on its own and coupled with MS. NMR data are highly reproducible and quantitative over a wide dynamic range and are unmatched for determining structures of unknowns. NMR is adept at tracing metabolic pathways and fluxes using isotope labels. Moreover, NMR is non-destructive and can be utilized in vivo. NMR results have a proven track record of translating in vitro findings to in vivo clinical applications

    Hadamard NMR spectroscopy for two-dimensional quantum information processing and parallel search algorithms

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    Hadamard spectroscopy has earlier been used to speed-up multi-dimensional NMR experiments. In this work we speed-up the two-dimensional quantum computing scheme, by using Hadamard spectroscopy in the indirect dimension, resulting in a scheme which is faster and requires the Fourier transformation only in the direct dimension. Two and three qubit quantum gates are implemented with an extra observer qubit. We also use one-dimensional Hadamard spectroscopy for binary information storage by spatial encoding and implementation of a parallel search algorithm.Comment: 28 pages, 10 figures. Journal of Magnetic Resonance (In Press

    Gefäßchirurgische Ausbildung in endovaskulärer Technik in Lausanne

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    Zusammenfassung: Zwischen 1995 und 2005 wuchs die Anzahl der jährlich von uns mit endovaskulären Techniken versorgten Aortenaneurysmen (EVAR) von 0 auf 50, und dies auf allen Stufen der Aorta. Zu unserer Organisation gehören ein breites Team von Chirurgen, ein Lager mit 3kompletten Familien von Endoprothesen (gerade Endoprothesen, konische Endoprothesen, und Bifurkationen), ein mobiler Wagen mit Zubehör (Einführungsbestecke, Führungsdrähte, Katheter, Ballone etc.) und ein Apparat auf Rädern für die intravaskuläre Ultraschalluntersuchung (IVUS). Letzterer erlaubt es zusammen mit einer mobilen Durchleuchtungsanlage (C-Bogen), in jedem Operationssaal unserer Institution endovaskulär Aneurysmen zu analysieren, und dies in der Regel ohne Angiographie bzw. Kontrastmittel. Deshalb sind wir nicht mehr auf eine ausgiebige bildgebende präoperative Abklärung potenzieller Kandidaten für eine endovaskuläre Sanierung von Aneurysmen angewiesen und können rupturierte Aneurysmen der Bauchaorta oder der thorakalen Aorta ohne Verzug behandeln. Bei der endovaskulären Sanierung von Aortenaneurysmen unterscheiden wir zwischen Prozessschritten (Indikationsstellung, Darstellung der Zugangsgefäße, Ausmessen mittels IVUS und Roadmapping mittels Durchleuchtung, Implantatwahl, Implantatinsertion, Positionierung, Implantatabwurf, Erfolgsbeurteilung, Rekonstruktion der Zugangsgefäße und Nachkontrolle) und Kompetenzstufen (Assistent, Oberarzt, Leitender Arzt). Unsere ultraschallgestützte Technik zur endovaskulären Sanierung von Aneurysmen wurde mittels IVUS-Transporter und Telementoring erfolgreich auch anderen Institutionen zur Verfügung gestell

    Order-Disorder Transitions Govern Kinetic Cooperativity and Allostery of Monomeric Human Glucokinase

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    Glucokinase (GCK) catalyzes the rate-limiting step of glucose catabolism in the pancreas, where it functions as the body's principal glucose sensor. GCK dysfunction leads to several potentially fatal diseases including maturity-onset diabetes of the young type II (MODY-II) and persistent hypoglycemic hyperinsulinemia of infancy (PHHI). GCK maintains glucose homeostasis by displaying a sigmoidal kinetic response to increasing blood glucose levels. This positive cooperativity is unique because the enzyme functions exclusively as a monomer and possesses only a single glucose binding site. Despite nearly a half century of research, the mechanistic basis for GCK's homotropic allostery remains unresolved. Here we explain GCK cooperativity in terms of large-scale, glucose-mediated disorder-order transitions using 17 isotopically labeled isoleucine methyl groups and three tryptophan side chains as sensitive nuclear magnetic resonance (NMR) probes. We find that the small domain of unliganded GCK is intrinsically disordered and samples a broad conformational ensemble. We also demonstrate that small-molecule diabetes therapeutic agents and hyperinsulinemia-associated GCK mutations share a strikingly similar activation mechanism, characterized by a population shift toward a more narrow, well-ordered ensemble resembling the glucose-bound conformation. Our results support a model in which GCK generates its cooperative kinetic response at low glucose concentrations by using a millisecond disorder-order cycle of the small domain as a "time-delay loop," which is bypassed at high glucose concentrations, providing a unique mechanism to allosterically regulate the activity of human GCK under physiological conditions.NIH [1R01DK081358]NIHNSF [MCB-0918362]NSFAmerican Heart AssociationAmerican Heart Associatio

    Conformational Exchange Processes in Biological Systems: Detection by Solid-State NMR

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    International audienceWe review recent advances in methodologies to study microseconds-to-milliseconds exchange processes in biological molecules using magic-angle spinning solid-state nuclear magnetic resonance (MAS ssNMR) spectroscopy. The particularities of MAS ssNMR, as compared to solution-state NMR, are elucidated using numerical simulations and experimental data. These simulations reveal the potential of MAS NMR to provide detailed insight into short-lived conformations of biological molecules. Recent studies of conformational exchange dynamics in microcrystalline ubiquitin are discussed

    Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food

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    The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.Peer reviewe

    Spin dynamics in finite cyclic XY model

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    Evolution of the z-component of a single spin in the finite cyclic XY spin 1/2 chain is studied. Initially one selected spin is polarized while other spins are completely unpolarized and uncorrelated. Polarization of the selected spin as a function of time is proportional to the autocorrelation function at infinite temperature. Initialization of the selected spin gives rise to two wave packets moving in opposite directions and winding over the circle. We express the correlation function as a series in winding number and derive tractable approximations for each term. This allows to give qualitative explanation and quantitative description to various finite-size effects such as partial revivals and transition from regular to erratic behavior.Comment: v2: substantially extended; v3: references added, accepted to Phys. Rev.
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