138 research outputs found

    Enantioselective Alkynylation of Trifluoromethyl Ketones Catalyzed by Cation-Binding Salen Nickel Complexes

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    Cation‐binding salen nickel catalysts were developed for the enantioselective alkynylation of trifluoromethyl ketones in high yield (up to 99 %) and high enantioselectivity (up to 97 % ee). The reaction proceeds with substoichiometric quantities of base (10–20 mol % KOt‐Bu) and open to air. In the case of trifluoromethyl vinyl ketones, excellent chemo‐selectivity was observed, generating 1,2‐addition products exclusively over 1,4‐addition products. UV‐vis analysis revealed the pendant oligo‐ether group of the catalyst strongly binds to the potassium cation (K⁺) with 1:1 binding stoichiometry (K_a=6.6×10⁵ M⁻¹)

    Recalibration and validation of the Charlson Comorbidity Index in acute kidney injury patients underwent continuous renal replacement therapy

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    Background Comorbid conditions impact the survival of patients with severe acute kidney injury (AKI) who require continuous renal replacement therapy (CRRT). The weights assigned to comorbidities in predicting survival vary based on type of index, disease, and advances in management of comorbidities. We developed a modified Charlson Comorbidity Index (CCI) for use in patients with AKI requiring CRRT (mCCI-CRRT) and improved the accuracy of risk stratification for mortality. Methods A total of 828 patients who received CRRT between 2008 and 2013, from three university hospital cohorts was included to develop the comorbidity score. The weights of the comorbidities were recalibrated using a Cox proportional hazards model adjusted for demographic and clinical information. The modified index was validated in a university hospital cohort (n = 919) using the data of patients treated from 2009 to 2015. Results Weights for dementia, peptic ulcer disease, any tumor, and metastatic solid tumor were used to recalibrate the mCCI-CRRT. Use of these calibrated weights achieved a 35.4% (95% confidence interval [CI], 22.1%–48.1%) higher performance than unadjusted CCI in reclassification based on continuous net reclassification improvement in logistic regression adjusted for age and sex. After additionally adjusting for hemoglobin and albumin, consistent results were found in risk reclassification, which improved by 35.9% (95% CI, 23.3%–48.5%). Conclusion The mCCI-CRRT stratifies risk of mortality in AKI patients who require CRRT more accurately than does the original CCI, suggesting that it could serve as a preferred index for use in clinical practice

    Effects of residential greenness on clinical outcomes of patients with chronic kidney disease: a large-scale observation study

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    Background: As industrialization and urbanization are accelerating, the distribution of green areas is decreasing, particularly in developing countries. Since the 2000s, the effects of surrounding greenness on self-perceived health, including physical and mental health, longevity, and obesity have been reported. However, the effects of surrounding green space on chronic kidney disease are not well understood. Therefore, we investigated the impact of residential greenness on the mortality of chronic kidney disease patients and progression from chronic kidney disease to end-stage renal disease (ESRD). Methods: Using a large-scale observational study, we recruited chronic kidney disease patients (n = 64,565; mean age, 54.0 years; 49.0% of male) who visited three Korean medical centers between January 2001 and December 2016. We investigated the hazard ratios of clinical outcomes per 0.1-point increment of exposure to greenness using various models. Results: During the mean follow-up of 6.8 +/- 4.6 years, 5,512 chronic kidney disease patients developed ESRD (8.5%) and 8,543 died (13.2%). In addition, a 0.1-point increase in greenness reduced all-cause mortality risk in chronic kidney disease and ESRD patients and progression of chronic kidney disease to ESRD in a fully adjusted model. The association between mortality in ESRD patients and the normalized difference vegetation index was negatively correlated in people aged >65 years, who had normal weight, were nonsmokers, and lived in a nonmetropolitan area. Conclusion: Chronic kidney disease patients who live in areas with higher levels of greenness are at reduced risk of all-cause mortality and progression to ESRD.Y

    Clinical outcomes associated with long-term exposure to airborne particulate pollution in kidney transplant recipients

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    Background Researchers have yet to investigate the specific association between 10-μm particulate matter (PM10) levels and the risk of graft failure, kidney disease, or the functional decline of transplanted kidneys, in kidney transplant recipients (KTRs). Furthermore, we know very little about the association between PM10 levels and the development of allograft rejection in transplanted kidneys. Identification of air pollution as a potential contributor to kidney disease could help reduce future disease burden, stimulate policy discussions on the importance of reducing air pollution with respect to health and disease, and increase public awareness of the hazards of air pollution. We aimed to evaluate the relationship of PM10 with the risk of graft failure, mortality, and decline of graft function in KTRs. Methods Air pollutant data were obtained from the Korean National Institute of Environmental Research. We then investigated potential associations between these data and the clinical outcomes of 1532 KTRs who underwent kidney transplantation in a tertiary hospital between 2001 and 2015. Survival models were used to evaluate the association between PM10 concentrations and the risk of death-censored graft failure (DCGF), all-cause mortality, and biopsy-proven rejection (BPR), over a median follow-up period of 6.31 years. Results The annual mean PM10 exposure after kidney transplantation was 27.1 ± 8.0 μg/m3. Based on 1-year baseline exposure, 1 μg/m3 increase in PM10 concentration was associated with an increased risk of DCGF (hazard ratio (HR): 1.049; 95% confidence interval (CI): 1.014–1.084) and BPR (HR: 1.053; 95% CI: 1.042–1.063). Fully adjusted models showed that all-cause mortality was significantly associated with 1-year average PM10 concentrations (HR, 1.09; 95% CI, 1.043 to 1.140). Conclusions Long-term PM10 exposure is significantly associated with BPR, DCGF, and all-cause mortality in KTRs.This work was supported by the Seoul National University Research Grant in 2018, the Korean Society of Nephrology Grant in 2018 (BAXTER), and by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2019R1A6A3A01095329) and the Global Research Lab through the NRF, funded by the Ministry of Science and ICT (Information and Communication Technologies) in South Korea (grant number K2100400000110A0500–00710; H Kim)

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    Visible Light-Promoted Synthesis of Spiroepoxy Chromanone Derivatives via a Tandem Oxidation/Radical Cyclization/Epoxidation Process

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    A highly efficient and straightforward approach for the synthesis of spiroepoxy chroman-4-one derivatives was developed using a visible light-enabled tandem radical strategy. The reaction is initiated by the formation of an acyl radical that undergoes intramolecular radical cyclization and epoxidation. The optimal result was obtained with 1 mol% of Ru(bpy)(3)Cl(2)6H(2)O, TBHP, and K2CO3 in i-PrOAc at room temperature with irradiation from a blue LED. This unprecedented tandem approach utilizes a broad range of substrates, and provides a convenient and powerful synthetic tool for accessing the synthetically useful spiroepoxy chroman-4-ones and their nitrogen-containing derivatives © 2018 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.1331sciescopu

    Initial Glaucoma Medication in the Hypertensive Phase Following Ahmed Valve Implantation: A Comparison of Results Achieved Using Aqueous Suppressants and Prostaglandin Analogs

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    Background: To compare the effects of aqueous suppressants (AS) and prostaglandin (PG) analogs during the hypertensive phase on intraocular pressure (IOP) and surgical outcomes. Methods: In this retrospective, observational study, 66 eyes (66 patients) with Ahmed glaucoma valve (AGV) implantation were included. As evaluation items, IOP changes, number of postoperative medications, the surgical success rate, and postoperative complications were examined. Complete success was defined as IOP between 6 and 21 mmHg without medications, while qualified success was with a maximum of four medications. Results: The short-term IOP reduction following initial medication was 9.3 mmHg for AS and 4.4 mmHg for PG analogs (p = 0.016). More postoperative medications were used in PG than in AS from postoperative 3 months to 3 years (all p < 0.05). The qualified success rate with the initial medication was higher in AS than in PG (67.5% vs. 42.3% at 1 year, 80.6% vs. 37.5% at 2 years, 80.0% vs. 35.0% at 3 years, all p < 0.05). Conclusions: Association between AS used as the first medications during the hypertensive phase and better IOP control and a higher success rate was observed. The type of the initial glaucoma medication after AGV implantation could affect short- and long-term surgical outcomes
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