755 research outputs found

    Silica nanowires templated by amyloid-like fibrils

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    Many peptides self-assemble to form amyloid fibrils. We previously explored the sequence propensity to form amyloid using variants of a designed peptide with sequence KFFEAAAKKFFE. These variant peptides form highly stable amyloid fibrils with varied lateral assembly and are ideal to template further assembly of non-proteinaceous material. Herein, we show that the fibrils formed by peptide variants can be coated with a layer of silica to produce silica nanowires using tetraethyl-orthosilicate. The resulting nanowires were characterized using electron microscopy (TEM), X-ray fiber diffraction, FTIR and cross-section EM to reveal a nanostructure with peptidic core. Lysine residues play a role in templating the formation of silica on the fibril surface and, using this library of peptides, we have explored the contributions of lysine as well as arginine to silica templating, and find that sequence plays an important role in determining the physical nature and structure of the resulting nanowires

    Retroperitoneal fibrosis and β-blocking agents:Is there an association?

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    AIM: Retroperitoneal fibrosis (RPF) is a rare chronic fibro-inflammatory disorder which may be secondary to certain drugs, including beta-blocking agents (BBAs). However, their causative role is unclear. We aimed to investigate this association. METHODS: Disproportionality analysis was carried out on cases from 1985 to October 4, 2020 in VigiBase®, the WHO pharmacovigilance database. The Bayesian-based IC025 metric and reporting odds ratio were used in order to assess the adverse event signal. We also analysed all published case reports from the literature regarding BBA-associated RPF to assess the value of suggested supportive clinical evidence. RESULTS: 1.599 individual case safety reports (ICSRs) of RPF were reported to VigiBase®, of which 132 (32%) concerned 16 different single BBA. For 12 of these agents (75%), reporting of RPF was disproportionate, indicating a potential safety signal. Line listing analysis of ICSRs showed no consistent time interval from start of BBA to RPF diagnosis (range 0,7-264 mo). Dechallenge was negative or unknown in the majority of cases (74%). In 18 published cases from the literature, time from start of BBA to RPF diagnosis varied widely (range 3-156 mo). BBA were discontinued 6 mo before (n=1) or at the time of RPF diagnosis (n=17). Most patients (84%) also received RPF specific treatment. Follow-up (FU) duration was short (median 5 mo [range 1-24 mo]) and in most cases (83%) relevant FU data were lacking. CONCLUSION: Although disproportionality analysis indicated a potential safety signal for RPF associated with BBAs, clinical evidence did not support a cause and effect relationship

    Agrarische structuur, trends en beleid: ontwikkelingen in Nederland vanaf 1950

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    In en rond de agrarische sector in Nederland hebben zich de afgelopen decennia ingrijpende veranderingen voorgedaan. Zo is het aandeel van de agrarische sector in de nationale economie stelselmatig teruggelopen. Dit rapport brengt de structurele veranderingen in kaart en analyseert de invloed van beleidsmaatregelen. Geconcludeerd wordt dat de processen van bedrijfsbeëindiging en schaalvergroting die zich in de land/ en tuinbouw voordoen, vooral bepaald zijn door het duurder worden van arbeid, in combinatie met het beschikbaar komenvan arbeidsbesparende technische mogelijkheden.Fundamental changes have taken place in and around the Dutch agricultural sector during the past decades, and the agriculture sector¿s share in the national economy has exhibited a consistent decline. This report maps the structural changes in the sector and analyses the influence of policy measures. The report concludes that the processes resulting in the closure of farms and increases in scale are primarily determined by the increasing cost of labour incombination with the availability of labour/saving technology

    Evaluation of a patient decision aid for BRCA1/2 pathogenic variant carriers choosing an ovarian cancer prevention strategy

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    OBJECTIVE: Risk-reducing surgery is advised to BRCA1/2 pathogenic variant (PV) carriers around the age of 40 years to reduce ovarian cancer risk. In the TUBA-study, a multicenter preference study (NCT02321228), BRCA1/2-PV carriers are offered a choice: the standard strategy of risk-reducing salpingo-oophorectomy or the novel strategy of risk-reducing salpingectomy with delayed oophorectomy. We evaluated feasibility and effectiveness of a patient decision aid for this choice. METHODS: Premenopausal BRCA1/2-PV carriers were counselled for risk-reducing surgical options in the TUBA-study; the first cohort was counselled without and the second cohort with decision aid. Evaluation was performed using digital questionnaires for participating women and their healthcare professionals. Outcome measures included actual choice, feasibility (usage and experiences) and effectiveness (knowledge, cancer worry, decisional conflict, decisional regret and self-estimated influence on decision). RESULTS: 283 women were counselled without and 282 women with decision aid. The novel strategy was chosen less frequently in women without compared with women with decision aid (67% vs 78%, p = 0.004). The decision aid was graded with an 8 out of 10 by both women and professionals, and 78% of the women would recommend this decision aid to others. Users of the decision aid reported increased knowledge about the options and increased insight in personal values. Knowledge on cancer risk, decisional conflict, decisional regret and cancer worry were similar in both cohorts. CONCLUSIONS: The use of the patient decision aid for risk-reducing surgery is feasible, effective and highly appreciated among BRCA1/2-PV carriers facing the decision between salpingo-oophorectomy or salpingectomy with delayed oophorectomy

    TUBectomy with delayed oophorectomy as an alternative to risk-reducing salpingo-oophorectomy in high-risk women to assess the safety of prevention:the TUBA-WISP II study protocol

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    BACKGROUND: Risk-reducing salpingectomy with delayed oophorectomy has gained interest for individuals at high risk for tubo-ovarian cancer as there is compelling evidence that especially high-grade serous carcinoma originates in the fallopian tubes. Two studies have demonstrated a positive effect of salpingectomy on menopause-related quality of life and sexual health compared with standard risk-reducing salpingo-oophorectomy.PRIMARY OBJECTIVE: To investigate whether salpingectomy with delayed oophorectomy is non-inferior to the current standard salpingo-oophorectomy for the prevention of tubo-ovarian cancer among individuals at high inherited risk.STUDY HYPOTHESIS: We hypothesize that postponement of oophorectomy after salpingectomy, to the age of 40-45 (BRCA1) or 45-50 (BRCA2) years, compared with the current standard salpingo-oophorectomy at age 35-40 (BRCA1) or 40-45 (BRCA2) years, is non-inferior in regard to tubo-ovarian cancer risk.TRIAL DESIGN: In this international prospective preference trial, participants will choose between the novel salpingectomy with delayed oophorectomy and the current standard salpingo-oophorectomy. Salpingectomy can be performed after the completion of childbearing and between the age of 25 and 40 (BRCA1), 25 and 45 (BRCA2), or 25 and 50 (BRIP1, RAD51C, and RAD51D pathogenic variant carriers) years. Subsequent oophorectomy is recommended at a maximum delay of 5 years beyond the upper limit of the current guideline age for salpingo-oophorectomy. The current National Comprehensive Cancer Network (NCCN) guideline age, which is also the recommended age for salpingo-oophorectomy within the study, is 35-40 years for BRCA1, 40-45 years for BRCA2, and 45-50 years for BRIP1, RAD51C, and RAD51D pathogenic variant carriers.MAJOR INCLUSION/EXCLUSION CRITERIA: Premenopausal individuals with a documented class IV or V germline pathogenic variant in the BRCA1, BRCA2, BRIP1, RAD51C, or RAD51D gene who have completed childbearing are eligible for participation. Participants may have a personal history of a non-ovarian malignancy.PRIMARY ENDPOINT: The primary outcome is the cumulative tubo-ovarian cancer incidence at the target age: 46 years for BRCA1 and 51 years for BRCA2 pathogenic variant carriers.SAMPLE SIZE: The sample size to ensure sufficient power to test non-inferiority of salpingectomy with delayed oophorectomy compared with salpingo-oophorectomy requires 1500 BRCA1 and 1500 BRCA2 pathogenic variant carriers.ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS: Participant recruitment is expected to be completed at the end of 2026 (total recruitment period of 5 years). The primary outcome is expected to be available in 2036 (minimal follow-up period of 10 years).TRIAL REGISTRATION NUMBER: NCT04294927.</p

    Grain Boundaries in Graphene on SiC(0001ˉ\bar{1}) Substrate

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    Grain boundaries in epitaxial graphene on the SiC(0001ˉ\bar{1}) substrate are studied using scanning tunneling microscopy and spectroscopy. All investigated small-angle grain boundaries show pronounced out-of-plane buckling induced by the strain fields of constituent dislocations. The ensemble of observations allows to determine the critical misorientation angle of buckling transition θc=19± 2\theta_c = 19 \pm~2^\circ. Periodic structures are found among the flat large-angle grain boundaries. In particular, the observed θ=33±2\theta = 33\pm2^\circ highly ordered grain boundary is assigned to the previously proposed lowest formation energy structural motif composed of a continuous chain of edge-sharing alternating pentagons and heptagons. This periodic grain boundary defect is predicted to exhibit strong valley filtering of charge carriers thus promising the practical realization of all-electric valleytronic devices

    Comparison of Serum HBsAg Quantitation by Four Immunoassays, and Relationships of HBsAg Level with HBV Replication and HBV Genotypes

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    BACKGROUND: The decline in hepatitis B virus surface antigen (HBsAg) may be an early predictor of the viral efficacy of Hepatitis B virus (HBV) therapy. The HBsAg levels obtained by different immunoassays now need comparing and the relationships between levels of HBsAg and HBV DNA alongside HBsAg and genotype must be evaluated. METHODOLOGY/PRINCIPAL FINDINGS: HBsAg levels were compared among 80 patients using the Abbott Architect assay, a commercial immunoassay approved for HBsAg detection and quantitation, and three other assays derived from immunoassays approved for HBsAg detection (manufactured by Diasorin, Bio-Rad and Roche). Good correlation was found between the Abbot vs. Diasorin, Bio-Rad and Roche assays with narrow 95% limits of agreement and small mean differences: -0.06 to 0.11, -0.09 log(10) IU/mL; -0.57 to 0.64, -0.04 log(10) IU/mL; -0.09 to 0.45, -0.27 log(10) IU/mL, respectively. These agreements were not affected by genotypes A or D. HBsAg was weakly correlated with HBV DNA, whatever the HBsAg assay used: Abbott, ρ = 0.36 p = 0.001, Diasorin ρ = 0.34, p = 0.002; Bio-Rad ρ = 0.37, p<0.001; or Roche ρ = 0.41, p<0.001. This relationship between levels of HBsAg and HBV DNA seemed to depend on genotypes. Whereas HBsAg (Abbott assay) tended to correlate with HBV DNA for genotype A (ρ = 0.44, p = 0.02), no such correlation was significant for genotypes D (ρ = 0.29, p = 0.15). CONCLUSION/SIGNIFICANCE: The quantitation of HBsAg in routine clinical samples is comparable between the reference assay and the adapted assays with acceptable accuracy limits, low levels of variability and minimum discrepancy. While HBsAg quantitation is not affected by HBV genotype, the observed association between levels of HBsAg and HBV DNA seems genotype dependent

    HPLC-DAD and HPLC-ESI-Q-ToF characterisation of early 20th century lake and organic pigments from Lefranc archives

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    The characterisation of atelier materials and of the historical commercial formulation of paint materials has recently gained new interest in the field of conservation science applied to modern and contemporary art, since modern paint materials are subjected to peculiar and often unpredictable degradation and fading processes. Assessing the composition of the original materials purchased by artists can guide not only their identification in works of art, but also their restoration and conservation. Advances in characterisation methods and models for data interpretation are particularly important in studying organic coloring materials in the transition period corresponding to the late 19th-early 20th century, when many such variants or combinations were hypothetically possible in their formulations. There is thus a need for reliable databases of materials introduced in that period and for gaining chemical knowledge at a molecular level related to modern organic pigments, by state-of-the-art protocols. This paper reports on the results of a study on 44 samples of historical colorants in powder and paint tubes, containing both lake pigments and synthetic organic pigments dating from 1890 to 1926. The samples were collected at the Lefranc Archive in Le Mans (France) as a part of Project Futurahma "From Futurism to Classicism (1910-1922). Research, Art History and Material Analysis", (FIRB2012, Italian Ministry of University and Research), and were investigated using an analytical approach based on chromatographic and mass spectrometric techniques. The focus of the chemical analyses was to reveal the composition of the historical organic lake pigments including minor components, to discriminate between different recipes for the extraction of chromophore-containing molecules from the raw materials, and ultimately to distinguish between different formulations and recipes. High performance liquid chromatography (HPLC) with diode array detector (DAD) or electrospray-Quadrupole-Time of Flight tandem mass spectrometry detector (ESI-Q-ToF) were chosen given their considerable capacity to identify such complex and widespread organic materials. Although the inorganic components of the pigments were not taken into account in this survey, the specific molecular profiles provided invaluable information on the extraction procedures or synthetic strategy followed by the different producers, at different times. For instance, the use of Kopp's purpurin and garancine was highlighted, and synthetic by-products were identified. The results provided evidence that the addition of synthetic organic pigments to paint mixtures started from 1910 onwards, but they also suggest that in the formulation of high quality (surfin) colorants, natural products were still preferred. Moreover, in one of the samples the use of murexide as the colouring material was confirmed. This paper presents the first systematic and comprehensive survey on organic lakes and pigments belonging to an historical archive, by both HPLC-DAD and HPLC-ESI-Q-ToF. Specific by-products of synthetic production of pigments, which can act as specific molecular markers for dating or locating a work of art, were also identified for the first time
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