Weighted Network Degree Screening Method for Low-Temperature Combustion Mechanism Reduction.

A new method is proposed for the reduction mechanism used in the low-temperature negative temperature coefficient region on the basis of the statistical degree screening (SDS) method. Dynamic information is used to redefine network structure and exclude the influence of very weak interactions on node degree according to the statistics character of their distribution as edge weight. Representative low-temperature conditions are used to set weight thresholds to redefine the network structure so that an effective low-temperature oxidation mechanism is covered while negligible interactions are overlooked. Then, the reduction mechanism is obtained by the SDS method through screening out the redundant species and corresponding reactions according to the scale-free character of the degree distribution. This weighted network degree screening (WNDS) method is demonstrated in the n-heptane system. The performance of the reduced mechanism is evaluated in a closed homogeneous reactor for the fuel over T = 600-1000 K, P = 1-30 atm, and φ = 0.5-2. Results show WNDS yields a skeletal mechanism with comparable or even better prediction ability over a wide parameter range than those generated by directed relation graph. WNDS is a novel statistical property-based reduction method that is suitable for low-temperature oxidation reduction. Its good reduction application indicates a brand-new angle for large combustion mechanism reduction.

Community Reaction Network Reduction for Constructing a Coarse-Grained Representation of Combustion Reaction Mechanisms.

A community-reaction network reduction (CNR) approach is presented for mechanism reduction on the basis of a network-based community detection technique, a concept related to pre-equilibrium in chemical kinetics. In this method, the detailed combustion mechanism is first transformed into a weighted network, in which communities of species that have dense inner connections under the critical ignition conditions are identified. By analyzing the community partitions in different regions, we determine the effective functional groups and driving processes. Then, a skeletal model for the overall mechanism is deduced according to the network centrality data, including transition pathway identification and reaction-path flux. The CNR method is illustrated on the hydrogen autoignition system which has been extensively investigated, and a new reduced mechanism involving seven processes is proposed. Dynamics simulations employing the present CNR model show that the computed ignition time and distribution of major species on a wide range of temperature and pressure conditions are in accord with the experiments and results from other methods.

Association of m.5178C>A variant with serum lipid levels: a systematic review and meta-analysis.

BACKGROUND: Emerging evidence shows that m.5178C>A variant is associated with a lower risk of coronary artery disease (CAD). However, the specific mechanisms remain elusive. Since dyslipidemia is one of the most critical risk factors for CAD and accounts for at least 50% of the population-attributable risk, it is tempting to speculate that the reduced CAD risk caused by the m.5178C>A variant may stem from an improved lipid profile. In order to verify this hypothesis, we conducted the present study to clarify the association of m.5178C>A variant with lipid levels. METHODS: By searching ten databases for studies published before 30 June 2021. Thirteen East Asian populations (7587 individuals) were included for the analysis. RESULTS: The present study showed that m.5178C>A variant was associated with higher high-density lipoprotein cholesterol (HDL-C) [standardized mean difference (SMD) = 0.12, 95% confidence interval (CI) = 0.06-0.17, P<0.001] and total cholesterol (TC) (SMD = 0.08, 95% CI = 0.02-0.14, P=0.01) levels. In subgroup analysis, the association of m.5178C>A variant with higher HDL-C levels were observed in Japanese (SMD = 0.09, 95% CI = 0.01-0.17, P=0.03) and Chinese populations (SMD = 0.13, 95% CI = 0.07-0.20, P<0.001). However, the association of m.5178C>A variant with lower low-density lipoprotein cholesterol (LDL-C) levels were only observed in Japanese populations (SMD = -0.11, 95% CI = -0.22 to 0.00, P=0.04). CONCLUSIONS: The m.5178C>A variant was associated with higher HDL-C and lower LDL-C levels in Japanese populations, which may contribute to decreased CAD risk and longevity of Japanese.

CircRNA ACAP2 Is Overexpressed in Myocardial Infarction and Promotes the Maturation of miR-532 to Induce the Apoptosis of Cardiomyocyte.

ABSTRACT: CircRNA ACAP2 and miR-532 both promotes the apoptosis of cardiomyocytes, which contributes to myocardial infarction (MI). Therefore, ACAP2 and miR-532 may interact with each other to participate in MI. Plasma samples from both patients with MI (n = 65) and healthy controls (n = 65) were subjected to RNA extractions and real-time quantitative polymerase chain reaction to analyze the expression of ACAP2, mature miR-532, and premature miR-532. Correlations among them were analyzed by Pearson's correlation coefficient. Expression of both mature miR-532 and premature miR-532 in cardiomyocytes with ACAP2 overexpression was analyzed by real-time quantitative polymerase chain reaction to study the effects of ACAP2 overexpression on the maturation of miR-532. The role of ACAP2 and miR-532 in regulating the apoptosis of cardiomyocytes induced by hypoxia was analyzed by cell apoptosis assay. In this study, we found that ACAP2 and mature miR-532 were both upregulated in plasma from patients with MI. ACAP2 and mature miR-532 were inversely correlated, whereas ACAP2 and premature miR-532 were not significantly correlated. In cardiomyocytes, overexpression of ACAP2 increased the expression of mature miR-532, but not premature miR-532. Cell apoptosis analysis showed that ACAP2 and miR-532 overexpression promoted the apoptosis of cardiomyocytes induced by hypoxia treatment. In addition, miR-532 inhibitor reduced the effects of ACAP2 overexpression. ACAP2 is overexpressed in MI and may promote the maturation of miR-532 to induce the apoptosis of cardiomyocyte.

Association of with-no-lysine kinase 1 and Serine/Threonine kinase 39 gene polymorphisms and haplotypes with essential hypertension in Tibetans.

Tibetans have a higher essential hypertension prevalence compared with other ethnics in China. The reason might be due to their unique environmental influence, as well as genetic factor. However, limited studies focus on Tibetan genetics and its association with hypertension. The aim of this study was to investigate the association between With-No-Lysine (K) Kinase 1 (WNK1), Serine/Threonine kinase 39(STK39) genes variants and hypertension in the Tibetan population. 204 Tibetan hypertensive patients and 305 normotensive controls were recruited in an epidemiological survey conducted at 2 sites in the Ganzi Tibetan autonomous region. Patients were genotyped for nineteen WNK1 candidate tag single nucleotide polymorphisms (SNPs) and three STK39 SNPs, and haplotype analysis was performed. Results showed that the allele A in rs1468326 was overrepresented in hypertensive patients versus control (53.4% vs 42.9%, P < 0.05). The multivariable-adjusted odds ratio (OR) for hypertension among CA + AA genotypes carriers was 1.60 (95% CI: 1.02-2.62, P < 0.05), and they also had a higher systolic blood pressure (136.5 ± 28.6 vs 131.7 ± 24.8 mmHg, P < 0.05). However, the TT genotype ratio in rs6749447 was lower in hypertensives (5.4% vs 10.8%, P < 0.05), and the hypertension risk for the TT genotype carriers in rs6749447 decreased after adjustment (OR 0.49, 95% CI 0.19-0.95, P < 0.05). Subjects with haplotype AGACAGGAATCGT showed 1.57 times higher risk of hypertension (95% CI 1.02-2.41, P < 0.05). In conclusion, SNP rs1468326 of WNK1, rs6749447 of STK39, and WNK1 haplotype AGACAGGAATCGT were associated with hypertension in Tibetan individuals. Environ. Mol. Mutagen. 59:151-160, 2018. © 2017 Wiley Periodicals, Inc.

[Effects of new body shape index on prevalence of diabetes mellitus and fasting blood glucose].

OBJECTIVE: To evaluate the effects of a new body shape index (ABSI) on the prevalence of diabetes mellitus (DM) and Fasting blood-glucose (FBG) in elders in Chengdu. METHODS: In May 2007, a total of 685 subjects were recruited by random sampling, with an average age of (63.3±10.2) years. All subjects received standardized questionnaires, physical examinations and laboratory tests for analyzing the relationship between ABSI with the prevalence of FBG and DM. RESULTS: The overall trend of FBG increased with rising ABSI (P<0.001). But the impact of ABSI on the prevalence trend of DM was not obvious (P=0.334). According to logistic regression analysis adjusting for confounders, ABSI was not a risk factor of DM. Relative to the lowest quartile of ABSI, the odds ratio of DM prevalence was 1.093 (95% CI: 0.617-1.937, P=0.761), 0.844 (95% CI: 0.469-1.517, P=0.570) and 0.684 (95% CI: 0.373-1.256, P=0.221) at the second, third and fourth quartiles respectively. CONCLUSION: ABSI is not associated with the prevalence of DM in middle-aged and elderly people in Chengdu. Further cohort study are required for clarifying the ethnic difference of ABSI.

The TG/HDL-C Ratio Might Be a Surrogate for Insulin Resistance in Chinese Nonobese Women.

Obejective. To examine the discriminatory power of triglyceride (TG) and triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C) for insulin resistance (IR) in a normoglycaemic Chinese population. Methods. The data were collected from 711 individuals. The normoglycaemic individuals were eventually included in the study (n = 533, age: 62.8 ± 6.6 years, male: 56.8%), who were with a fasting plasma glucose < 6.1 mmol/L and without a history of diabetes. IR was defined as the upper quintile (≥1.6) of homeostasis model assessment of IR. Area under the receiver operating characteristic curve (AROC) was used to examine the discriminatory power. Results. The discriminatory power of TG/HDL-C for IR was acceptable in women with a BMI < 24 kg/m(2) or waist circumference < 80 cm (AROCs: 0.718 and 0.713, resp.); however, the discriminatory power was not acceptable in the obese women. TG/HDL-C was not an acceptable marker of IR in men. The discriminatory power of TG for IR was not acceptable in both men and women. Conclusions. The discriminatory power of TG/HDL-C for IR differs by gender and obesity index in the normoglycaemic Chinese population, and TG/HDL-C could discriminate IR in the nonobese and normoglycaemic women.

Hypertriglyceridemic waist might be an alternative to metabolic syndrome for predicting future diabetes mellitus.

BACKGROUND: In some cross-sectional studies, hypertriglyceridemic waist (HTGW) has been recommended as an alternative to metabolic syndrome (MetS) for screening individuals at high risk for diabetes mellitus (DM). However, little information is about the predictive power of HTGW for future DM. The aims of the study were to assess the DM predictive power of HTGW compared with MetS based on the follow-up data over 15 years collected from a general Chinese population. METHODS: And Findings: The data were collected in 1992 and then again in 2007 from the same group of 687 individuals without DM in 1992. For the whole population (n =687), multivariate analysis showed presence of HTGW was associated with a 4.1-fold (95%CI: 2.4-7.0, p < 0.001) increased risk and presence of MetS was associated with a 3.7-fold (95%CI: 2.2-6.2, p < 0.001) increased risk for future DM. For the population without elevated fasting plasma glucose (n = 650), multivariate analysis showed presence of HTGW was associated with a 3.9-fold (95%CI: 2.2-7.0, p < 0.001) increased risk and presence of MetS was associated with a 3.7-fold (95%CI: 2.1-6.6, p < 0.001) increased risk for future DM. CONCLUSIONS: HTGW could predict future DM independently, and the predictive power was similar to MetS. HTGW might be an alternative to MetS for predicting future DM. For simpler and fewer components, HTGW might be more practical than MetS, and it might be recommended in most clinical practices. This finding might be more useful for the individuals who only have elevated WC and TG. Although these individuals are without MetS, they are still at high risk for future DM, similarly to the individuals with MetS.

The effects of initial and subsequent adiposity status on diabetes mellitus.

BACKGROUND: Obesity in adulthood is associated with increased risk for diabetes mellitus (DM). It is uncertain whether this risk is attenuated in adulthood who are overweight or obese initially but not obese subsequently. METHODS AND RESULTS: The data were collected in 1992 and then again in 2007 from the same group of 687 participants (male: 58.1%, age: 48.1 ± 6.2 years).The participants were categorized into four groups on the basis of adiposity status in 1992 and 2007: group I included subjects with a normal BMI in 1992 and 2007; group II, those with a normal BMI in 1992 who were overweight or obese in 2007; group III, those who were overweight or obese in 1992 but normal BMI in 2007; and group IV, those who were overweight or obese in 1992 and 2007. With group I as reference, the HR is 0.818 for group II (95% CI: 0.341-1.962, p=0.653), 2.231 for group III (95% CI: 1.087-4.579, p=0.029) and 1.855 for group IV (95% CI: 1.049-3.279, p=0.034) after adjustment for confounders. It was not significantly different between groups I and II, as well as between groups III and IV. CONCLUSION: In adulthood, becoming nonobese could not reverse the adverse effects of obesity on DM, as compared with the subjects who persist being overweight or obese. Keeping weight in the normal BMI range should be emphasized in the public for preventing DM.

Downregulation of peroxisome proliferator-activated receptor-gamma expression in hypertensive atrial fibrillation.

BACKGROUND: Numerous evidence has suggested that either hypertension or atrial fibrillation (AF) is associated with systemic inflammation. Peroxisome proliferator-activated receptor-gamma (PPARgamma) has been proved to have anti-inflammatory effects and is implicated as a molecular pathway involved in many cardiovascular diseases, such as hypertension. The correlation between PPARgamma inflammation and AF is still unknown. METHODS: Using a case-control study design, 57 patients with hypertensive AF (persistent AF: 32, paroxysmal AF: 25) were included into the study groups. A total of 32 age-matched patients with hypertension, but without AF were selected as the control group. The expressions of PPARgamma, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) mRNA in monocytes were detected by using a reverse transcription-polymerase chain reaction (RT-PCR). Interleukin-1 (IL-1) was measured by immunoenzymetric methods. RESULTS: The PPARgamma mRNA was markedly decreased in the hypertensive AF group as compared with the hypertensive non-AF group, and it was significantly lower in persistent AF than paroxysmal AF (0.222 +/- 0.0702 vs 0.564 +/- 0.0436, P<0.01). TNF-alpha mRNA, IL-6 mRNA, and IL-1 were increased in patients with hypertensive AF compared to the non-AF group and it was even higher in persistent AF than in paroxysmal AF (0.721 +/- 0.0541 vs 0.530 +/- 0.0496, 0.567 +/- 0.044 vs 0.457 +/- 0.0505, 325.61 +/- 88.10 vs 190.65 +/- 59.38, respectively, P<0.01). TNF-alpha, IL-6, and IL-1 were in negative correlation with PPARgamma, the correlation coefficient was -0.854, -0.769, and -0.702, respectively (P<0.01). CONCLUSIONS: In hypertensive patients, increased inflammatory cytokines were associated with increased incidence of AF and atrial remodeling; PPARgamma may be involved in the pathogenesis of AF by regulation of inflammation.