43 research outputs found

    Preoperative P-wave duration as a predictor of atrial fibrillation after coronary artery bypass grafting: A prospective cohort study with meta-analysis

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    Objectives: Reported prediction rules for postoperative atrial fibrillation (AF) have suffered from inconsistent results and controversy surrounding the predictive value of a preoperative P-wave duration (PreOPWD). This study examined PreOPWD as a predictor for AF after coronary artery bypass grafting (CABG). Methods: Two-hundred-and-ninety-nine patients with sinus rhythm before off-pump CABG were recruited into the study. Patients' demographic and clinical data were evaluated prospectively. Patients were continuously monitored for the first seven postoperative days. Multiple logistic regression was used to determine significant predictors of AF. Findings were then combined with similar studies and a meta-analysis was performed. Results: Postoperative AF was observed in 33.1% of 299 patients. Patients with AF were older, had a prolonged PreOPWD, higher incidences of hypertension, aortic regurgitation, and mitral regurgitation. A cut-off point of PreOPWD≥105 ms achieved a specificity of 74%, and a sensitivity of 65% for predictive of AF. Multivariate analysis showed that PreOPWD≥105 ms (odds ratio [OR] 4.63, 95% confidence intervals [CI] 2.66 to 8.03, P < 0.001), age≥60 years (OR 2.72, 95% CI 1.51 to 4.90, P < 0.01) and hypertension (OR 2.10, 95% CI 1.08 to 4.07, P < 0.05) independently predicted postoperative AF. A meta-analysis of this data combined with those of ten other studies showed that PreOPWD was greater in patients with POAF, with a weighted mean difference of 3.95 ms (95% CI 1.97 to 5.92, P < 0.001). Conclusion: This study confirmed, among other predictive characteristics, that PreOPWD is a powerful independent predictor of POAF. Keywords: Atrial fibrillation, Coronary artery bypass, Off-pump, Cohort studies, Meta-analysi

    A study of esterification of caffeic acid with methanol using p-toluenesulfonic acid as a catalyst

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    Caffeic acid (CA) can be considered as an important natural antioxidant. However, the low solubility and stability of CA in various solvent systems is a major limiting factor governing the overall application in the lipid industry, so the synthesis of methyl caffeate (MC)using CA and methanol is a feasible way to improve its lipophilicity. Here, the reaction conditions and kinetic parameters for the synthesis of MC using p-toluenesulfonic acid (PTSA) as a catalyst were firstly investigated, and the product was confirmed byliquid chromatography-mass spectrometry (LC-MS),Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and melting point analysis. The highest yield of MC catalyzed by PTSA reached 84.0% under the optimum conditions as follows: molar ratio of methanol to CA of 20:1, reaction temperature of 65°C, mass ratio of catalyst to substrate of 8 %, and reaction time of 4 h. The esterification kinetics of CA and methanol is described by the pseudo-homogeneous second order reversible model, the relationship between temperature and the forward rate constant is k1 = exp (358.7 - 2111/T), and the activation energy is 17.5 kJ mol-1. These results indicated that the PTSA possesses high catalytic activity in the synthesis of MC, which is an efficient catalyst suitable for MC production in the chemical industry

    Effect of Different Initial CaO/SiO<sub>2</sub> Molar Ratios and Curing Times on the Preparation and Formation Mechanism of Calcium Silicate Hydrate

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    To better understand the pozzolanic activity in fly ash used as a supplementary cementitious material in cement or concrete, calcium silicate hydrate (C-S-H) has been synthesized by adding silica fume to a supersaturated calcium hydroxide solution prepared by mixing calcium oxide and ultrapure water. Thermogravimetric analysis results have revealed the variation in the weight loss due to C-S-H in the samples and the conversion ratio of calcium oxide (the μCaO value), which represents the proportion of calcium oxide in the initial reaction mixture used to produce C-S-H, with curing time. The weight loss due to C-S-H and the μCaO value were both maximized (13.5% and 90.4%, respectively) when the initial C/S molar ratio was 1.0 and the curing time was 90 d. X-ray diffraction (XRD) analysis has indicated that C-S-H in the samples after curing for 7 d had the composition Ca1.5SiO3.5·xH2O. 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) analysis has revealed that the degree of polymerization of C-S-H increased with an increase in curing time for samples with an initial C/S molar ratio of 1.0. The ratio of internal to terminal tetrahedra (Q2/Q1) increased from 2.29 to 4.28 with the increase in curing time from 7 d to 90 d. At curing times ≥ 28 d, a leaf-like C-S-H structure was observed by scanning electron microscopy (SEM). An ectopic nucleation–polymerization reaction process is proposed for the formation mechanism of C-S-H

    Solid waste-based dry-mix mortar using fly ash, carbide slag, and flue gas desulfurization gypsum

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    The hydration characteristics, performance, and economic feasibility of inorganic cementitious materials prepared using circulating fluidized bed fly ash (FA), carbide slag (CS), and flue-gas-desulfurization gypsum (FGDG) are investigated, focusing particularly on FA-CS binary and FA-CS-FGDG ternary cementitious systems. Experimental results show that the compressive strength of the binary system is less than that of the ternary one. The ternary cementitious material exhibits strong synergistic effects, as the 28 days compressive strength of the ternary system can reach 6.35 MPa, suggesting that it has good prospects for practical application. A dry-mixed mortar using the material has been manufactured and tested in a pilot project; it meets Chinese government quality standards and reduces cost and carbon emissions relative to traditional mortar. The 28 days compressive strength of dry mix mortar can reach 13.1 MPa, the production cost of solid waste-based dry-mixed mortar was reduced by approximately 48.8%, and the carbon dioxide emission reduction ratio was 82.9%

    Lyotropic Liquid Crystal Precursor as an Innovative Herpes Simplex Virus Vector for Melanoma Therapy

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    To overcome the low-efficiency toxic side effects and high recurrence of traditional therapy for malignant melanoma, an in situ gel system, HSV-LLCP, was developed as a local treatment for malignant melanoma in this study. This system was based on a lyotropic liquid crystal precursor (LLCP) loading with oncolytic virus herpes simplex virus-1 (HSV-1). With the unique lattice structure, HSV-LLCP, which could enhance the stability of HSV-1 and arrest HSV-1 at the injection site. The performance of LLCP as a virus vector was evaluated comprehensively. The HSV-LLCP showed a rapid gelling property (within 2 s) and the shear viscosity ranged from 5 to 9 mPa·s. The result also revealed the outstanding stability of HSV-LLCP. The release behavior showed a triphasic sustained-release pattern during the experiment period. In addition, HSV-LLCP exhibited a superior oncolytic activity compared to the HSV-1 solution in murine melanoma B16 cells. This study showed that HSV-LLCP would become an alternative and promising HSV-1 vector with high safety and stability for melanoma treatment in the clinic

    Associations between Variants in IL-33/ST2 Signaling Pathway Genes and Coronary Heart Disease Risk

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    The IL-33/ST2 signaling pathway plays an important role in coronary artery disease (CHD); however, few studies have explored how variants in IL-33/ST2 genes influence CHD risk. Here, we examined the association between genetic variants in IL-33, ST2, and IL-1RAcP of the IL-33/ST2 axis and the risk of CHD. We conducted a case-controlled study with 1146 CHD cases and 1146 age- and sex-frequency-matched controls. Twenty-eight single nucleotide polymorphisms (SNPs) in IL-33, ST2, and IL-1RAcP were genotyped by Sequenom MassArray and TaqMan assay. Logistic regression was used to analyze these associations. The SNP rs4624606 in IL-1RAcP was nominally associated with CHD risk. The AA genotype was associated with a 1.85-fold increased risk of CHD (95% confidence interval (CI) = 1.01–3.36; p = 0.045) compared to the TT genotype. Further analysis showed that AA carriers also had a higher risk of CHD than TT + TA carriers (odds ratio (OR) = 1.85; 95% CI = 1.85–3.35; p = 0.043). However, no significant association was observed between variants in IL-33/ST2 genes and CHD risk. Further studies are needed to replicate our results in other ethnic groups with larger sample size

    Research of Multi-Fuel Burning Stability In A 300MW Coal-Fired Utility Boiler

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    AbstractWith China's economy growing rapidly, requirement of electricity is more and more. Now, 300MW coal-fired units are main units. With diversification of coal, there are big differences between actual coal and design coal, this affect on the safety of running. In this paper, a 300MW coal-fired unit was studied. A, B and C three kinds of mixed coal were chosen. Under the rated load, characteristics of coal were studied. Experiments of adaptabilities of mixed coal A, B and C with boiler were done. And results indicated that slag of boiler was related with distribution of fire box temperature, degree of flame-brush wall and degree of flue-gas turbidness. Slag of mixed coal C was serious, while mixed coal A was not easy lagging in superheater and water wall. Therefore, mixed coal A as fuel could meet the need of safe running of boiler

    Vehicle-Free Nanotheranostic Self-Assembled from Clinically Approved Dyes for Cancer Fluorescence Imaging and Photothermal/Photodynamic Combinational Therapy

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    Phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT) has attracted growing attention as a noninvasive option for cancer treatment. At present, researchers have developed various &ldquo;all-in-one&rdquo; nanoplatforms for cancer imaging and PTT/PDT combinational therapy. However, the complex structure, tedious preparation procedures, overuse of extra carriers and severe side effects hinder their biomedical applications. In this work, we reported a nanoplatform (designated as ICG-MB) self-assembly from two different FDA-approved dyes of indocyanine green (ICG) and methylene blue (MB) without any additional excipients for cancer fluorescence imaging and combinational PTT/PDT. ICG-MB was found to exhibit good dispersion in the aqueous phase and improve the photostability and cellular uptake of free ICG and MB, thus exhibiting enhanced photothermal conversion and singlet oxygen (1O2) generation abilities to robustly ablate cancer cells under 808 nm and 670 nm laser irradiation. After intravenous injection, ICG-MB effectively accumulated at tumor sites with a near-infrared (NIR) fluorescence signal, which helped to delineate the targeted area for NIR laser-triggered phototoxicity. As a consequence, ICG-MB displayed a combinational PTT/PDT effect to potently inhibit tumor growth without causing any system toxicities in vivo. In conclusion, this minimalist, effective and biocompatible nanotheranostic would provide a promising candidate for cancer phototherapy based on current available dyes in clinic

    Alanine&ndash;Glyoxylate Aminotransferase Sustains Cancer Stemness Properties through the Upregulation of SOX2 and OCT4 in Hepatocellular Carcinoma Cells

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    Liver cancer stem cells (LCSCs) are a small subset of oncogenic cells with a self-renewal ability and drug resistance, and they promote the recurrence and metastasis of hepatocellular carcinoma (HCC). However, the mechanisms regulating LCSCs have not been fully explored. By enriching LCSCs from spheroid cultures and performing transcriptomic analysis, we determined that alanine&ndash;glyoxylate aminotransferase (AGXT), which participates in the metabolism of serine and glycine, was significantly upregulated in spheroid cultures, and its function in LCSCs remains unknown. Through the exogenous overexpression or short hairpin RNA knockdown of AGXT in HCC cells, we observed that changes in the AGXT level did not affect the spheroid ability and population of LCSCs. The knockdown of AGXT in LCSCs reduced the number of spheroids and the population of LCSCs; this implies that AGXT is required for the maintenance of cancer stemness rather than as a driver of LCSCs. Mechanistically, AGXT may sustain the self-renewal potential of LCSCs by upregulating the expression of SRY-box transcription factor 2 (SOX2) and octamer-binding transcription factor 4 (OCT4), two well-known master regulators of cancer stemness. Taken together, our study demonstrates the role of AGXT in supporting LCSCs; thus, AGXT merits further exploration

    Machine Learning Algorithms Identify Pathogen-Specific Biomarkers of Clinical and Metabolomic Characteristics in Septic Patients with Bacterial Infections

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    Sepsis is a high-mortality disease that is infected by bacteria, but pathogens in individual patients are difficult to diagnosis. Metabolomic changes triggered by microbial activity provide us with the possibility of accurately identifying infection. We adopted machine learning methods for training different classifiers with a clinical-metabolomic database from sepsis cases to identify the pathogen of sepsis. Records of clinical indicators and concentration of metabolites were obtained for each patient upon their arrival at the hospital. Machine learning algorithms were used in 100 patients with clear infection and corresponding 29 controls to select specific biosignatures to discriminate microorganism in septic patients. The sensitivity, specificity, and AUC value of clinical and metabolomic characteristics in predicting diagnostic outcomes were determined at admission. Our analyses demonstrate that the biosignatures selected by machine learning algorithms could have diagnostic value on the identification of infected patients and Gram-positive from Gram-negative; related AUC values were 0.94±0.054 and 0.80±0.085, respectively. Pathway and blood disease enrichment analyses of clinical and metabolomic biomarkers among infected patients showed that sepsis disease was accompanied by abnormal nitrogen metabolism, cell respiratory disorder, and renal or intestinal failure. The panel of selected clinical and metabolomic characteristics might be powerful biomarkers to discriminate patients with sepsis
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