53 research outputs found

    An accelerated first-order method with complexity analysis for solving cubic regularization subproblems

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    We propose a first-order method to solve the cubic regularization subproblem (CRS) based on a novel reformulation. The reformulation is a constrained convex optimization problem whose feasible region admits an easily computable projection. Our reformulation requires computing the minimum eigenvalue of the Hessian. To avoid the expensive computation of the exact minimum eigenvalue, we develop a surrogate problem to the reformulation where the exact minimum eigenvalue is replaced with an approximate one. We then apply first-order methods such as the Nesterov's accelerated projected gradient method (APG) and projected Barzilai-Borwein method to solve the surrogate problem. As our main theoretical contribution, we show that when an ϵ\epsilon-approximate minimum eigenvalue is computed by the Lanczos method and the surrogate problem is approximately solved by APG, our approach returns an ϵ\epsilon-approximate solution to CRS in O~(ϵ1/2)\tilde O(\epsilon^{-1/2}) matrix-vector multiplications (where O~()\tilde O(\cdot) hides the logarithmic factors). Numerical experiments show that our methods are comparable to and outperform the Krylov subspace method in the easy and hard cases, respectively. We further implement our methods as subproblem solvers of adaptive cubic regularization methods, and numerical results show that our algorithms are comparable to the state-of-the-art algorithms

    Clinical Temporal Relation Extraction with Probabilistic Soft Logic Regularization and Global Inference

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    There has been a steady need in the medical community to precisely extract the temporal relations between clinical events. In particular, temporal information can facilitate a variety of downstream applications such as case report retrieval and medical question answering. Existing methods either require expensive feature engineering or are incapable of modeling the global relational dependencies among the events. In this paper, we propose a novel method, Clinical Temporal ReLation Exaction with Probabilistic Soft Logic Regularization and Global Inference (CTRL-PG) to tackle the problem at the document level. Extensive experiments on two benchmark datasets, I2B2-2012 and TB-Dense, demonstrate that CTRL-PG significantly outperforms baseline methods for temporal relation extraction.Comment: 10 pages, 4 figures, 7 tables, accepted by AAAI 202

    Formation of sclerotia in Sclerotinia ginseng and composition of the sclerotial exudate

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    Background Sclerotinia ginseng is a major devastating soil-borne pathogen of ginseng that can cause irreparable damage and large economic losses. This pathogen produces sclerotia, which are among the most persistent resting structures produced by filamentous fungi. The production of an exudate is a common feature of sclerotial development. Methods S. ginseng was cultured on 10 different media and the following parameters were measured: mycelial growth rate (mm/day), initial formation time of exudate droplets, total quantity of exudate, number of sclerotia per dish, and sclerotial fresh/dry weight. The composition of the sclerotial exudate was analyzed using four methods (high performance liquid chromatography, gas chromatography-mass spectrometry, flame atomic absorption spectrometry, and Nessler’s reagent spectrophotometry). Results We found that PDA was the optimal medium for exudate production, while SDA medium resulted in the highest mycelial growth rate. The earliest emergence of exudate droplets from sclerotia was on OA-YE and V8 media. The largest amount of sclerotia and the smallest sclerotia were produced on V8 medium. The maximum and minimum dry/fresh weight were obtained on MEA medium and V8 medium, respectively. The exudate contained organic acids (oxalic acid, gallic acid, ferulic acid, vanillic acid, caffeic acid, and tannic acid), carbohydrates (inositol, glucose, and trehalose), various ions (potassium, sodium, and magnesium), and ammonia. Discussion The functions of the identified compounds are discussed within the context of pathogenicity, sclerotial development, and antimicrobial activity. Our findings provide information about the production of sclerotia and the composition of sclerotial exudate that may be useful to develop strategies to control this disease

    Ecdysone Elicits Chronic Renal Impairment via Mineralocorticoid-Like Pathogenic Activities

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    Background/Aims: Ecdysteroids are steroidal insect molting hormones that also exist in herbs. Ecdysteroid-containing adaptogens have been popularly used to improve well-being and by bodybuilders for muscle growth. However, the use of ecdysone in mammals is also associated with kidney growth and enlargement, indications of disturbed kidney homeostasis. The underlying pathogenic mechanism remains to be clarified. Methods: Virtual screening tools were employed to identify compounds that are homologous to ecdysone and to predict putative ecdysone-interacting proteins. The kidney effect of ecdysone was examined in vitro and in vivo and compared with that of aldosterone. Cellular apoptosis was estimated by terminal deoxynucleotidyl transferase dUTP nick end labeling. Cell motility was assessed by scratch-wound cell migration assay. Blood urea nitrogen was measured to evaluate renal function. Western immunblot analysis was employed to determine the expression profile of interested proteins. Results: Computational molecular structure analysis revealed that ecdysone is highly homologous to aldosterone. Moreover, virtual screening based on compound-protein interaction profiles identified the Mineralocorticoid Receptor (MR) to potentially interact with ecdysone. Accordingly, to assess potential biological functions of ecdysone in mammals, ecdysone was applied to mineralocorticoid-sensitive inner medullar collecting duct cells. Ecdysone induced mesenchymal accumulation of extracellular matrix and epithelial dedifferentiation characterized by de novo expression of α-smooth muscle actin. In addition, ecdysone elicited cellular apoptosis and retarded cell motility, akin to the effect of aldosterone. In vivo, daily treatment of mice with ecdysone increased cell apoptosis in the kidney, impaired renal function and elicited early signs of renal fibrogenesis, marked by deposition of collagen and fibronectin in tubulointerstitium, reminiscent of the action of aldosterone. The MR signaling pathway is likely responsible for the cellular and pathobiological effects of ecdysone, as evidenced by strong ecdysone-induced MR nuclear translocation in renal tubular cells both in vitro and in vivo, while blockade of MR by concomitant spironolactone treatment largely abolished the detrimental effects of ecdysone. Conclusion: Our findings suggest that ecdysone induces mineralocorticoid-dependent activities that impair renal function and elicit renal injury

    Pyrolysis characteristics and kinetics of β-cyclodextrin and its two derivatives

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    β-cyclodextrin (β-CD) and its derivatives have been widely used to prepare inclusion complexes. However, systematic research on their thermal stabilities, pyrolysis characteristics and kinetics has rarely been reported. In this paper, thermogravimetric analysis was employed to investigate β-cyclodextrin and its two derivatives, 2-Hydroxypropyl-β-cyclodextrin (HP-β-CD) and monochlorotriazinyl-β-cyclodextrin (MCT-β-CD). The pyrolysis characteristics and kinetic parameters were obtained. The results show that three stages can be distinguished during the heating process of the above three samples. The temperature of initial decomposition of HP-β-CD (309.5°C is higher than that of β-CD (297.8°C), while the temperature of initial decomposition of MCT-β-CD (231.4°C) is lower than that of β-CD. For the three cyclodextrins, the thermal stability in descending order is HP-β-CD, β-CD and MCT-HP-β-CD. The activation energy values are 350.6, 303.3 and 113.9 KJ/mol, and the pre-exponential factor values are 1.11×1031, 1.37×1026 and 1.39×1010 for β-CD, HP-β-CD and MCT-β-CD respectively

    Molecular detection of Cylindrocarpon destructans in infected Chinese ginseng roots and soil

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    Ginseng (<i>Panax ginseng</i> C.A. Meyer) is one of the most important medicinal plants in China, but its yields are often reduced by a variety of root pathogens. The root rot of ginseng is a destructive soil-borne disease caused by Cylindrocarpon destructans (teleomorph: Neonectria radicicola). A species-specific polymerase chain reaction (PCR) assay was developed for rapid detection of C. destructans in diseased ginseng roots and artificially inoculated soil. One pair of specific primers was designed from comparisons of nucleotide sequences of the nuclear ribosomal internal transcribed spacer (ITS) regions of 22 fungal isolates from northeast of China. Under stringent PCR conditions, primers CD-F and CD-R amplified only a 450 bp fragment from C. destructans DNA but not from other pathogens or negative control. The sensitivity of detection was 1 pg genomic DNA per 25 ìl PCR reaction volume, and C. destructans could be specifically detected with CD-F/CD-R from infected ginseng roots and soil. The approach outlined here could be further utilized as a rapid and reliable tool for the diagnosis and monitoring of the root rot of ginseng.Key words: Panax ginseng, Cylindrocarpon destructans, internal transcribed spacer (ITS), polymerase chain reaction (PCR), molecular detection

    Knowledge, attitudes, practices, and self-efficacy of the Chinese public regarding cardiopulmonary resuscitation: an online cross-sectional survey

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    ObjectiveTo evaluate the current status of Chinese public’s knowledge, attitudes, practices (KAP) and self-efficacy regarding cardiopulmonary resuscitation (CPR), and to analyze the factors that influence KAP and self-efficacy.MethodsAn online cross-sectional survey was conducted from February to June 2022 in Mainland China via a self-designed self-filled questionnaire. Potential participants were recruited through WeChat by convenience sampling and snowball sampling methods. Descriptive and quantitative analyses were used for statistical analysis.ResultsThe survey included 4,450 participants from 31 provinces, autonomous regions, or municipalities across Mainland China, aged 18 or above. The public’s average understanding (clear and very clear) of the knowledge regarding CPR was 67.4% (3,000/4,450), with an average proportion of positive attitudes at 96.8% (4,308/4,450). In practice, the average proportion of good practices was 92.8% (4,130/4,450), while the percentage of good self-efficacy averaged at 58.9% (2,621/4,450), only 42.4% (1,885/4,450) of the participants had confidence in the correct use of automated external defibrillator (AED). Pearson correlation analysis showed a significantly positive correlation among knowledge, attitude, practice, and self-efficacy (p < 0.01). Multiple linear regression analysis revealed that several factors have a significant influence on the public’s CPR KAP and self-efficacy, including ever having received CPR training (p < 0.001), hearing about AED (p < 0.001), performing CPR on others (p < 0.001), hearing about CPR (p < 0.001), occupation (p < 0.001), personal health status (p < 0.001), education level (p < 0.001), gender (p < 0.001), and encountering someone in need of CPR (p = 0.021).ConclusionThe Chinese public demonstrates good knowledge of CPR, positive attitude, and high willingness to perform CPR. However, there is still room for improvement in the mastery of some professional knowledge points related to CPR and AED. It should be noted that knowledge, attitude, practice, and self-efficacy are interrelated and influence each other. Factors such as prior CPR training, hearing about AED, having performed CPR before, hearing about CPR, occupation, personal health status, education level, gender, and having encountered someone in need of CPR have a significant impact on the public’s KAP and self-efficacy

    Encapsulation of hydroxycitronellal in β-cyclodextrin and the characteristics of the inclusion complex

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    Hydroxycitronellal has been widely used in foods, beverages, perfumery and cosmetics. It can also be used to treat anxiety. The major drawbacks regarding the use of hydroxycitronellal are related to water insolubility, volatility, instability, and sensitization. To overcome these concerns, β-cyclodextrin was adopted as wall material to encapsulate hydroxycitronellal in this work. Hydroxycitronellal-β-cyclodextrin inclusion complex was prepared and the product was characterized. The interaction of hydroxycitronellal and β-cyclodextrin, and the assembly of hydroxycitronellal-β-cyclodextrin inclusion complex were investigated by molecular simulation (MM). The results showed that hydroxycitronellal loading capacity was 8.5%. The thermal stability and lastingness of hydroxycitronellal were im-proved by the formation of the inclusion complex. The minimum binding energy was –151.2 kJ/mol. Among the perpendicular, staggered parallel and ideally parallel orientation of the inclusion complexes, the minimum energy value was found for the staggered parallel arrangement. These basic data are useful to understand the interaction between hydroxycitronellal and β-cyclodextrin
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