311 research outputs found

    Simulation of phosphorus implantation into silicon with a single-parameter electronic stopping power model

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    We simulate dopant profiles for phosphorus implantation into silicon using a new model for electronic stopping power. In this model, the electronic stopping power is factorized into a globally averaged effective charge Z1*, and a local charge density dependent electronic stopping power for a proton. There is only a single adjustable parameter in the model, namely the one electron radius rs0 which controls Z1*. By fine tuning this parameter, we obtain excellent agreement between simulated dopant profiles and the SIMS data over a wide range of energies for the channeling case. Our work provides a further example of implant species, in addition to boron and arsenic, to verify the validity of the electronic stopping power model and to illustrate its generality for studies of physical processes involving electronic stopping.Comment: 11 pages, 7 figures. See http://bifrost.lanl.gov/~reed

    Evolution of the EGFR pathway in Metazoa and its diversification in the planarian Schmidtea mediterranea

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    This study was funded by grants, BFU2012-31701 and BFU2015-65704-P(Ministerio de Economia y Competitividad/Feder (Spain)) and 2009-SGR-1018 from the Generalitat de Catalunya to FC. SB was supported by a FI fellowship from the Generalitat de Catalunya and a collaboration fellowship from IBUB. JMMD was supported by Marie Curie IEF 329024 fellowship and Sars core budg

    A Novel Integrative Methodology for Research on Pot-honey Variations During Post-harvest

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    This novel review of analytical methods for pot-honey research was intended to provide concise references to a 35-day post-harvest experiments at 30 °C, in an integrated study. Diverse methods were selected from specialized literature, from the AOAC (Association of Official Analytical Chemists), and the International Honey Commission. Besides the geographical and seasonal origin, the pot-honey I.D. consists of entomological and botanical identifications, the latter performed by acetolyzed or natural melissopalynology. The methods of this integrative study included: 1. Physicochemical analysis (Aw, color, moisture, pH, free acidity, lactone acidity, total acidity, hydroxymethylfurfural (HMF), and sugars by highperformance liquid chromatography HPLC), 2. Targeted proton nuclear magnetic resonance 1H-NMR metabolomics (sugars, ethanol, HMF, aliphatic organic acids, amino acids, and botanical markers), 3. Biochemical composition (flavonoids, polyphenols), 4. Antioxidant activity (ABTS 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid-free radical scavenging assay, DPPH 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, ferric reduction assay FRAP), 5. Microbial counts (aerobic plate, yeast and mold, Bacillus, and lactic acid bacteria count), 6. Honey microbiome profiling via independent-culture method: high-throughput bacteria and fungi based on amplicon sequencing approaches, 7. Sensory evaluation (odor, aroma, taste, persistence), and 8. Honey authenticity and biosurfactant tests by an interphase emulsion. A further section was included to provide basic information on the results obtained using each method. This was needed to explain the interacting components derived from pot-honey processing within the stingless bee nest and post-harvest transformations

    One hundred and twelve infected arthroplasties treated with ‘DAIR’ (debridement, antibiotics and implant retention): antibiotic duration and outcome

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    OBJECTIVES: We describe treatment failure rates by antibiotic duration for prosthetic joint infection (PJI) managed with debridement, antibiotics and implant retention (DAIR). METHODS: We retrospectively collected data from all the cases of PJI that were managed with DAIR over a 5 year period. Surgical debridement, microbiological sampling, early intravenous antibiotics and prolonged oral follow-on antibiotics were used. RESULTS: One hundred and twelve cases of PJI were identified. Twenty infections (18%) recurred during a mean follow-up of 2.3 years. The mean duration of antibiotic use was 1.5 years. Failure was more common after arthroscopic debridement, for previously revised joints and for Staphylococcus aureus infection. There were 12 failures after stopping antibiotics and 8 while on antibiotics [hazard ratio (HR) = 4.3, 95% confidence interval (CI) 1.4-12.8, P = 0.01]. However, during the first 3 months of follow-up, there were eight failures after stopping antibiotics and two while on antibiotics (HR = 7.0, 95% CI 1.5-33, P = 0.015). The duration of antibiotic therapy prior to stopping did not predict outcome. CONCLUSIONS: PJI may be managed by DAIR. The risk of failure with this strategy rises after stopping oral antibiotics, but lengthening antibiotic therapy may simply postpone, rather than prevent, failure

    Molecular genetic dissection of inflammatory linear verrucous epidermal naevus leads to successful targeted therapy

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    The article is available via Open Access. Click on the 'Additional link' above to access the full-text.Published version, accepted version (12 month embargo

    Evaluation of polygenic risk scores for breast and ovarian cancer risk prediction in BRCA1 and BRCA2 mutation carriers

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    Background: Genome-wide association studies (GWAS) have identified 94 common single-nucleotide polymorphisms (SNPs) associated with breast cancer (BC) risk and 18 associated with ovarian cancer (OC) risk. Several of these are also associated with risk of BC or OC for women who carry a pathogenic mutation in the high-risk BC and OC genes BRCA1 or BRCA2. The combined effects of these variants on BC or OC risk for BRCA1 and BRCA2 mutation carriers have not yet been assessed while their clinical management could benefit from improved personalized risk estimates. Methods: We constructed polygenic risk scores (PRS) using BC and OC susceptibility SNPs identified through population-based GWAS: for BC (overall, estrogen receptor [ER]-positive, and ER-negative) and for OC. Using data from 15 252 female BRCA1 and 8211 BRCA2 carriers, the association of each PRS with BC or OC risk was evaluated using a weighted cohort approach, with time to diagnosis as the outcome and estimation of the hazard ratios (HRs) per standard deviation increase in the PRS. Results: The PRS for ER-negative BC displayed the strongest association with BC risk in BRCA1 carriers (HR = 1.27, 95% confidence interval [CI] = 1.23 to 1.31, P = 8.2 x 10(53)). In BRCA2 carriers, the strongest association with BC risk was seen for the overall BC PRS (HR = 1.22, 95% CI = 1.17 to 1.28, P = 7.2 x 10(-20)). The OC PRS was strongly associated with OC risk for both BRCA1 and BRCA2 carriers. These translate to differences in absolute risks (more than 10% in each case) between the top and bottom deciles of the PRS distribution; for example, the OC risk was 6% by age 80 years for BRCA2 carriers at the 10th percentile of the OC PRS compared with 19% risk for those at the 90th percentile of PRS. Conclusions: BC and OC PRS are predictive of cancer risk in BRCA1 and BRCA2 carriers. Incorporation of the PRS into risk prediction models has promise to better inform decisions on cancer risk management

    Bioassay guided purification of the antimicrobial fraction of a Brazilian propolis from Bahia state

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    <p>Abstract</p> <p>Background</p> <p>Brazilian propolis type 6 (Atlantic forest, Bahia) is distinct from the other types of propolis especially due to absence of flavonoids and presence of other non-polar, long chain compounds, but presenting good <it>in vitro </it>and <it>in vivo </it>antimicrobial activity. Several authors have suggested that fatty acids found in this propolis might be responsible for its antimicrobial activity; however, so far no evidence concerning this finding has been reported in the literature. The goals of this study were to evaluate the antibacterial activity of the main pure fatty acids in the ethanolic extract and fractions and elucidate the chemical nature of the bioactive compounds isolated from Brazilian propolis type 6.</p> <p>Methods</p> <p>Brazilian propolis type 6 ethanolic extract (EEP), hexane fraction (H-Fr), major fatty acids, and isolated sub-fractions were analyzed using high performance liquid chromatography (HPLC), high resolution gas chromatography with flame ionization detection (HRGC-FID), and gas chromatography-mass spectrometry (GC-MS). Three sub-fractions of H-Fr were obtained through preparative HPLC. Antimicrobial activity of EEP, H-Fr, sub-fractions, and fatty acids were tested against <it>Staphyloccus aureus </it>ATCC 25923 and <it>Streptococcus mutans </it>Ingbritt 1600 using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).</p> <p>Results</p> <p>EEP and H-Fr inhibited the growth of the microorganisms tested; nevertheless, no antimicrobial activity was found for the major fatty acids. The three sub-fractions (1, 2, and 3) were isolated from H-Fr by preparative HPLC and only sub-fraction 1 showed antimicrobial activity.</p> <p>Conclusion</p> <p>a) The major fatty acids tested were not responsible for the antimicrobial activity of propolis type 6; b) Sub-fraction 1, belonging to the benzophenone class, was responsible for the antimicrobial activity observed in the present study. The identification of the bioactive compound will improve the development of more efficient uses of this natural product.</p

    Dissimilar responses of fungal and bacterial communities to soil transplantation simulating abrupt climate changes.

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    Both fungi and bacteria play essential roles in regulating soil carbon cycling. To predict future carbon stability, it is imperative to understand their responses to environmental changes, which is subject to large uncertainty. As current global warming is causing range shifts toward higher latitudes, we conducted three reciprocal soil transplantation experiments over large transects in 2005 to simulate abrupt climate changes. Six years after soil transplantation, fungal biomass of transplanted soils showed a general pattern of changes from donor sites to destination, which were more obvious in bare fallow soils than in maize cropped soils. Strikingly, fungal community compositions were clustered by sites, demonstrating that fungi of transplanted soils acclimatized to the destination environment. Several fungal taxa displayed sharp changes in relative abundance, including Podospora, Chaetomium, Mortierella and Phialemonium. In contrast, bacterial communities remained largely unchanged. Consistent with the important role of fungi in affecting soil carbon cycling, 8.1%-10.0% of fungal genes encoding carbon-decomposing enzymes were significantly (p &lt; 0.01) increased as compared with those from bacteria (5.7%-8.4%). To explain these observations, we found that fungal occupancy across samples was mainly determined by annual average air temperature and rainfall, whereas bacterial occupancy was more closely related to soil conditions, which remained stable 6 years after soil transplantation. Together, these results demonstrate dissimilar response patterns and resource partitioning between fungi and bacteria, which may have considerable consequences for ecosystem-scale carbon cycling
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