162 research outputs found

    Photodynamics and Ground State Librational States of ClF Molecule in solid Ar. Comparison of experiment and theory

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    Photodynamics calculations of a ClF molecule in solid Ar are compared to experimental results and a new interpretation is given for the observed femtosecond-pump-probe signal modulation. We analyze the round-trip and depolarization times for the excited state wave-packet motion and discuss the incorporation of lattice cage motions that partially explain the time dependence of the measured signal. Librational eigenstates and -energies are calculated by solving the rotational Schrödinger equation in the previously computed [T. Kiljunen, M. Bargheer, M. Gühr, and N. Schwentner, Phys. Chem. Chem. Phys. 6 (9), 2185-2197 (2004)] octahedral potentials that hinder free molecular rotation in the solids. The obtained level structure is compared to infrared-spectroscopic results. We comment on the correspondence between temperature effects in the classical dynamics of the nuclei and the quantum mechanical probability distributions. We find the combinative treatment of different simulation temperatures congruous for interpreting the experimental results at cryogenic conditions

    Librational motion of CO in solid Ar: Raman and IR spectra and quantum simulations

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    Rovibrational Raman spectra of CO molecules isolated in solid Ar were measured for the 9–30 K temperature range and compared to past and present IR spectra. The fundamental band appears as a triplet-split structure, where the center peak shows completely different response to temperature in the Raman and IR spectroscopies. The peak is sharp and stable in Raman but reversibly broadens beyond recognition in IR upon annealing. The red-shifted, intense line of the triplet is found thermally inert similarly in both spectroscopies. The third line is the weakest, and as concentration dependent, it is assigned to a dimer as before. The CO–H₂O impurity complex is identified as a side band. We employ crystal field and quantum chemical modeling to interpret the disparity between the spectroscopies. The stable and broadening lines are given assignments to double- and singlesubstitution sites, respectively. Thermal excitations are not effective in the former case of angularly tightconfined, deep potential well. In the single-substitutional case, the librational level structure shows up in discriminating between the Raman and IR selection rules. An effectively ΔJ = 0 totally symmetric transition is found for Raman that is uncoupled from lattice phonons and corresponding broadening mechanisms. The low-temperature limit necessitates the use of a fixed lattice approach while the warmer end of the range is best described with an adiabatic, pseudorotating lattice approach

    Characterization of vB_ApiM_fHyAci03, a novel lytic bacteriophage that infects clinical Acinetobacter strains

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    We present here the isolation and characterization of Acinetobacter pittii phage vB_ApiM_fHyAci03 (fHyAci03), which belongs to the family Myoviridae. The fHyAci03 genome was found to be 165,975 bp in length and predicted to contain 255 genes. While the whole genome was 92.4% identical to Acinetobacter baumannii phage KARL-1, phylogenetic analysis based on phage long distal tail fiber amino acid sequences assigned fHyAci03 and KARL-1 to different subclusters, reflecting their different host species. Together with phylogenetic analysis, genome comparisons indicated that fHyAci03 is a novel member of the subfamily Tevenvirinae. Host range experiments revealed that fHyAci03 could infect two clinical strains of Acinetobacter nosocomialis and six clinical strains of A. pittii. Thus, fHyAci03 is a novel lytic phage that infects clinical Acinetobacter strains and represents a potential new candidate to be used in phage therapy.Peer reviewe

    Integrins are not essential for entry of coxsackievirus A9 into SW480 human colon adenocarcinoma cells

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    Background: Coxsackievirus A9 (CV-A9) is a pathogenic enterovirus type within the family Picornaviridae. CV-A9 infects A549 human epithelial lung carcinoma cells by attaching to the aVβ6 integrin receptor through a highly conserved Arg-Gly-Asp (RGD) motif, which is located at the exposed carboxy-terminus of the capsid protein VP1 in all studied clinical isolates. However, genetically-modified CV-A9 that lacks the RGD motif (CV-A9-RGDdel) has been shown to be infectious in some cell lines but not in A549, suggesting that RGD-mediated integrin binding is not always essential for efficient entry of CV-A9.   Methods: Two cell lines, A549 and SW480, were used in the study. SW480 was the study object for the integrin-independent entry and A549 was used as the control for integrin-dependent entry. Receptor levels were quantitated by cell sorting and quantitative PCR. Antibody blocking assay and siRNA silencing of receptor-encoding genes were used to block virus infection. Peptide phage display library was used to identify peptide binders to CV-A9. Immunofluorescence and confocal microscopy were used to visualize the virus infection in the cells.   Results: We investigated the receptor use and early stages of CV-A9 internalization to SW480 human epithelial colon adenocarcinoma cells. Contrary to A549 infection, we showed that both CV-A9 and CV-A9-RGDdel internalized into SW480 cells and that function-blocking anti-αV integrin antibodies had no effect on the binding and entry of CV-A9. Whereas siRNA silencing of β6 integrin subunit had no influence on virus infection in SW480, silencing of β2-microglobulin (b2M) inhibited the virus infection in both cell lines. By using a peptide phage display screening, the virus-binding peptide identical to the N-terminal sequence of HSPA5 protein was identified and shown to block the virus infection in both A549 and SW480 cell lines. HSPA5 was also found to co-localize with CV-A9 at the SW480 cell periphery during the early stages of infection by confocal microscopy.   Conclusions: The data suggest that while aVβ6 integrin is essential for CV-A9 in A549 cell line, it is not required in SW480 cell line in which β2M and HSPA5 alone are sufficient for CV-A9 infection. This suggests that the choice of CV-A9 receptor(s) is dependent on the tissue/cellular environment.</p

    Contribution of anadromous fish to the diet of European catfish in a large river system

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    Many anadromous fish species, when migrating from the sea to spawn in fresh waters, can potentially be a valuable prey for larger predatory fish, thereby efficiently linking these two ecosystems. Here, we assess the contribution of anadromous fish to the diet of European catfish (Silurus glanis) in a large river system (Garonne, southwestern France) using stable isotope analysis and allis shad (Alosa alosa) as an example of anadromous fish. Allis shad caught in the Garonne had a very distinct marine delta(13)C value, over 8 per thousand higher after lipid extraction compared to the mean delta(13)C value of all other potential freshwater prey fish. The delta(13)C values of European catfish varied considerably between these two extremes and some individuals were clearly specializing on freshwater prey, whereas others specialized on anadromous fish. The mean contribution of anadromous fish to the entire European catfish population was estimated to be between 53% and 65%, depending on the fractionation factor used for delta(13)C

    Isolation and Characterization of Klebsiella Phages for Phage Therapy

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    Introduction: Klebsiella is a clinically important pathogen causing a variety of antimicrobial resistant infections in both community and nosocomial settings, particularly pneumonia, urinary tract infection, and sepsis. Bacteriophage (phage) therapy is being considered a primary option for the treatment of drug-resistant infections of these types. Methods: We report the successful isolation and characterization of 30 novel, genetically diverse Klebsiella phages. Results: The isolated phages span six different phage families and nine genera, representing both lysogenic and lytic lifestyles. Individual Klebsiella phage isolates infected up to 11 of the 18 Klebsiella capsule types tested, and all 18 capsule-types were infected by at least one of the phages. Conclusions: Of the Klebsiella-infecting phages presented in this study, the lytic phages are most suitable for phage therapy, based on their broad host range, high virulence, short lysis period and given that they encode no known toxin or antimicrobial resistance genes. Phage isolates belonging to the Sugarlandvirus and Slopekvirus genera were deemed most suitable for phage therapy based on our characterization. Importantly, when applied alone, none of the characterized phages were able to suppress the growth of Klebsiella for more than 12 h, likely due to the inherent ease of Klebsiella to generate spontaneous phage-resistant mutants. This indicates that for successful phage therapy, a cocktail of multiple phages would be necessary to treat Klebsiella infections.Peer reviewe

    Molecular Factors of Hypochlorite Tolerance in the Hypersaline Archaeon Haloferax volcanii

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    Halophilic archaea thrive in hypersaline conditions associated with desiccation, ultraviolet (UV) irradiation and redox active compounds, and thus are naturally tolerant to a variety of stresses. Here, we identified mutations that promote enhanced tolerance of halophilic archaea to redox-active compounds using Haloferax volcanii as a model organism. The strains were isolated from a library of random transposon mutants for growth on high doses of sodium hypochlorite (NaOCl), an agent that forms hypochlorous acid (HOCl) and other redox acid compounds common to aqueous environments of high concentrations of chloride. The transposon insertion site in each of twenty isolated clones was mapped using the following: (i) inverse nested two-step PCR (INT-PCR) and (ii) semi-random two-step PCR (ST-PCR). Genes that were found to be disrupted in hypertolerant strains were associated with lysine deacetylation, proteasomes, transporters, polyamine biosynthesis, electron transfer, and other cellular processes. Further analysis revealed a Delta psmA1 (alpha 1) markerless deletion strain that produces only the alpha 2 and beta proteins of 20S proteasomes was hypertolerant to hypochlorite stress compared with wild type, which produces alpha 1, alpha 2, and beta proteins. The results of this study provide new insights into archaeal tolerance of redox active compounds such as hypochlorite

    Taxonomy and nomenclature of some Fennoscandian Sawflies, with descriptions of two new species (Hymenoptera, Symphyta)

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    While working on an identification guide to the sawflies of Fennoscandia, we encountered numerous taxonomic problems, for some of which we present solutions. Dicrostema Benson, 1952 is a new synonym of Phymatoceropsis Rohwer, 1916, and not congeneric with Paracharactus MacGillivray, 1908. Two species occurring in Europe are transferred to Phymatoceropsis. Dolerus aericepsellus Heidemaa and Mutanen sp. nov. and Heptamelus viitasaarii Liston, Mutanen and Prous sp. nov. are described from Finland. Abia brevicornis Leach, 1817 nom. rev. is the valid name of Abia nitens auct. nec Linnaeus, and Abia nitens (Linnaeus, 1758) is the valid name for what has recently been called Abia sericea (Linnaeus, 1767). Tenthredo haemorrhoidalis Fabricius, 1781 is treated as an unplaced species of Hymenoptera, possibly Ichneumonoidea. Calameuta variabilis (Mocsáry, 1886) is the valid name of the species recently generally called C. haemorrhoidalis. Claremontia confusa (Konow, 1886) sp. rev. and Claremontia brevicornis (Brischke, 1883) are distinct species. Dolerus coracinus (Klug, 1818) is the valid name for D. anthracinus auct. Dolerus anthracinus (Klug, 1818) is a valid species similar to D. nitens Zaddach, 1859. Dolerus coruscans Konow, 1890 sp. rev. is a valid species. Dolerus junci (Stephens, 1835) is the valid name for Dolerus cothurnatus auct. Dolerus timidus (Klug, 1818) sp. rev. is distinguished from the similar D. pratensis (Linnaeus, 1758). A neotype is designated for Astatus punctatus Klug, 1803. Lectotypes are designated for 39 nominal species. 29 species group names are new junior synonyms. We present data on some species recently collected for the first time in Finland, including first records for the Palaearctic and West Palaearctic

    Gonad shielding in paediatric pelvic radiography: disadvantages prevail over benefit

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    Objective To re-evaluate gonad shielding in paediatric pelvic radiography in terms of attainable radiation risk reduction and associated loss of diagnostic information. Methods A study on patient dose and the quality of gonad shielding was performed retrospectively using 500 pelvic radiographs of children from 0 to 15 years old. In a subsequent study, 195 radiographs without gonad shielding were included. Patient doses and detriment adjusted risks for heritable disease and cancer were calculated with and without gonad shielding. Results For girls, gonad shields were placed incorrectly in 91% of the radiographs; for boys, in 66%. Without gonad shielding, the hereditary detriment adjusted risk for girls ranged between 0.1?×?10?6 and 1.3?×?10?6 and for boys between 0.3?×?10?6 and 3.9?×?10?6, dependent on age. With shielding, the reduction in hereditary risk for girls was on average 6?±?3% of the total risk of the radiograph, for boys 24?±?6%. Without gonad shielding, the effective dose ranged from 0.008 to 0.098 mSv. Conclusions With modern optimised X-ray systems, the reduction of the detriment adjusted risk by gonad shielding is negligibly small. Given the potential consequences of loss of diagnostic information, of retakes, and of shielding of automatic exposure-control chambers, gonad shielding might better be discontinued.Support TNWApplied Science

    A Deep Learning-Based Automated CT Segmentation of Prostate Cancer Anatomy for Radiation Therapy Planning-A Retrospective Multicenter Study

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    A commercial deep learning (DL)-based automated segmentation tool (AST) for computed tomography (CT) is evaluated for accuracy and efficiency gain within prostate cancer patients. Thirty patients from six clinics were reviewed with manual- (MC), automated- (AC) and automated and edited (AEC) contouring methods. In the AEC group, created contours (prostate, seminal vesicles, bladder, rectum, femoral heads and penile bulb) were edited, whereas the MC group included empty datasets for MC. In one clinic, lymph node CTV delineations were evaluated for interobserver variability. Compared to MC, the mean time saved using the AST was 12 min for the whole data set (46%) and 12 min for the lymph node CTV (60%), respectively. The delineation consistency between MC and AEC groups according to the Dice similarity coefficient (DSC) improved from 0.78 to 0.94 for the whole data set and from 0.76 to 0.91 for the lymph nodes. The mean DSCs between MC and AC for all six clinics were 0.82 for prostate, 0.72 for seminal vesicles, 0.93 for bladder, 0.84 for rectum, 0.69 for femoral heads and 0.51 for penile bulb. This study proves that using a general DL-based AST for CT images saves time and improves consistency
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