Extremal values of VDB topological indices over F-benzenoids with equal number of edges.

The utilization of molecular structure topological indices is currently a standing operating procedure in the structure-property relations research, especially in QSPR/QSAR study. In the past several year, generous molecular topological indices related to some chemical and physical properties of chemical compounds were put forward. Among these topological indices, the VDB topological indices rely only on the vertex degree of chemical molecular graphs. The VDB topological index of an $ n $-order graph $ G $ is defined as TI(G) = \sum\limits_{1\leq i\leq j\leq n-1}m_{ij}\psi_{ij}, $ where $ \{\psi_{ij}\} $ is a set of real numbers, $ m_{ij} $ is the quantity of edges linking an $ i $-vertex and another $ j $-vertex. Numerous famous topological indices are special circumstance of this expression. f-benzenoids are a kind of polycyclic aromatic hydrocarbons, present in large amounts in coal tar. Studying the properties of f-benzenoids via topological indices is a worthy task. In this work the extremum $ TI $ of f-benzenoids with given number of edges were determined. The main idea is to construct f-benzenoids with maximal number of inlets and simultaneously minimal number of hexagons in $ \Gamma_{m} $, where $ \Gamma_{m} $ is the collection of f-benzenoids with exactly $ m $ $ (m\geq19) $ edges. As an application of this result, we give a unified approach of VDB topological indices to predict distinct chemical and physical properties such as the boiling point, $ \pi $-electrom energy, molecular weight and vapour pressure etc. of f-benzenoids with fixed number of edges.

Association of Type D personality and mild cognitive impairment in patients with hypertension.

Objective: The aim of this study was to evaluate the association between Type D personality and mild cognitive impairment (MCI) in patients with hypertension. Methods: A total of 324 subjects with hypertension were included in the study. All of them completed questionnaires on demographic characteristics, Type D personality Scale, Montreal Cognitive Assessment (MoCA), Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI). The Type D personality effect was analyzed as both dichotomous and continuous methods. Results: The incidence of MCI was 56.5% in hypertensive individuals. Type D personality presenting as a dichotomous construct was an independent risk factor of MCI (odds ratio [OR] = 2.814, 95% confidence interval [CI] = 1.577-5.021, p < 0.001), after adjusting for ages, sex and some clinical factors. Meanwhile, main effect of negative affectivity component was independently related to the prevalence of MCI (OR = 1.087, 95%CI = 1.014-1.165, p = 0.019). However, associations between the main effect of social inhibition component (OR = 1.011, 95%CI = 0.924-1.107, p = 0.811) as well as the interaction of negative affectivity and social inhibition (OR = 1.013, 95%CI = 0.996-1.030, p = 0.127) with MCI were not found. Conclusion: The findings suggest that Type D personality is strongly associated with MCI in patients with hypertension. The negative affectivity component of the Type D appears to drive the correlations between Type D and MCI. These findings provide new ideas for studying the mechanisms underlying the relationship between personality and cognitive decline in hypertensive individuals.

Cumulative effect of risk and protective factors on unintentional injury for Chinese rural children: a nested case-control study.

BACKGROUND: Childhood unintentional injuries are the leading cause of death and disability for children. Despite the risk factors that lead to the occurrence of injuries have been identified, the relationship between cumulative effect of risk/protective factors and unintentional injuries is unclear. The aim of this study was to explore the cumulative effect of risk factors as well as protective factors and their interaction on unintentional injury to rural children. METHODS: We used a nested case-control study design from a cohort database. The study comprised 1696 children aged 6 to 14 years. Among them, 424 were cases with unintentional injury and 1272 were their matched control. After controlling for the significant sociodemographic variables, linear and logistic regression analyses were performed. RESULTS: The risk of unintentional injury increased with the increasing number of risk factors - RFI from 1 to 3 (ORRFI(1) = 0.978, 95% CI 0.739-1.296), (ORRFI(2) = 1.720, 95% CI 1.233-2.397), (ORRFI(3) = 5.162, 95% CI 3.129-8.517). PFI (1) was associated with lower risk of injury, but this association was at the edge of significance (p = 0.052). The increased risk in those with PFI (2) was not significant (p = 0.254). The severity of the unintentional injury significantly increased with the increasing number of the risk factors (p < 0.01), and significantly decreased with both the increasing number of protective factors (p = 0.001) and interaction of the risk and protective factors (p < 0.01).The interaction of RFI and PFI could explain 32.2% of the unintentional injury severity. CONCLUSIONS: According to the findings of the present study, cumulative risk factors and protective factors, as well as their interaction were associated with the occurrence and/ or severity of unintentional injury in children.

Cumulative effects of unintentional injury among rural children of Heilongjiang Province / 中国学校卫生

Objective@#To explore the cumulative effects of unintentional injury among children in rural area, in order to provide information for early intervention of unintentional injury.@*Methods@#Through multistage clustering sampling method, 2 109 primary caregivers of students from 8 rural primary and elementary schools of Heilongjiang Province were recruited. Strengths and Difficulties Questionnaire (SDQ), Injury Behavior Checklist (IBC), Perceptions of Risks and Hazards were used to collect as the risk factors, while Perceptions of Risks and Hazards (PSAPQ), Home Observation for Measurement of the Environment (HOME) and Knowledge, Attitude and Practice for Children Unintentional Injury (KAP) were also used as the protective factors. Risk factors index (RFI) and protective factors index (PFI) were computed in the study.@*Results@#The severity of unintentional injury were positively correlated with SDQ, IBC and perceptions of risks and hazards(r=0.15, 0.23, 0.12, P<0.01), and were negatively correlated with HOME, PSAPQ and KAP(r=-0.25, -0.14, -0.09, P<0.01). Hierarchical linear regression showed that the total scores of SDQ, IBC and environmental of HOME predicted the severity of unintentional injury which could explain 34% variant of unintentional injury. It also indicated that the severity of unintentional injury were positively correlated with RFI (β=0.21) and negatively correlated with PFI(β=-0.18), the interaction was significant(β=-0.11,R2=0.31)(P<0.01).@*Conclusion@#Both risk and protective factors of unintentional injury have cumulative effects on the severity of injury among rural children. The relationship between risk factors and injury could be mediated by protective factors.

Study of the relationship between the lifestyle of residents residing in fluorosis endemic areas and adult skeletal fluorosis.

The relationship between fluorosis and the lifestyle of adult residents of areas in which fluorosis is endemic was evaluated. A cross-sectional and case-control analysis was performed to study 289 villagers living in fluorosis endemic areas who drank the local water. Subjects were divided into skeletal fluorosis and non-skeletal fluorosis groups according to whether they were afflicted with skeletal fluorosis. A semi-quantitative food frequency questionnaire, homemade lifestyle questionnaires, and general characteristics were analyzed. The factors that affected the occurrence of skeletal fluorosis were determined by generalized estimating equations. Our results showed that protective factors against skeletal fluorosis included drinking boiled water, storing water in a ceramic tank, and ingesting fruits, vitamin A, thiamine, and folic acid. Risk factors for skeletal fluorosis were overweight status and obesity, drinking tea, drinking water without storage, and ingestion of oils, fats, and phosphorus. Our results demonstrate that skeletal fluorosis has a close relationship with lifestyle.

[The risk factors of chronic obstructive pulmonary disease in Heilongjiang province].

OBJECTIVE: To study the prevalence and risk factors of chronic obstructive pulmonary disease (COPD) in Heilongjiang province. METHODS: This was a population-based and cross-sectional survey on prevalence of COPD in Heilongjiang province from September 2013 to March 2014. The stratified-cluster-random sampling method was performed to collect the data from 4 478 people in 5 cities (Jixi, Daqing, Suihua, Yichun and Jiagedaqi). The subjects were interviewed with questionnaires and tested with spirometry. A post-bronchodilator FEV1/FVC<70% was defined as diagnostic of COPD. RESULTS: Completed and qualified data were obtained from 4 059 participants. The average prevalence of COPD was 7.3% (urban 6.0%; rural 8.8%; men 8.6%; women 6.5%). When using SPSS18.0 for the single factors logistic regression analysis, results indicated that sex (OR = 0.700, 95%CI:0.540-0.907), age ≥ 50 (OR = 1.236, 95%CI:0.758-2.017), lower education level (OR = 1.551, 95%CI:0.929-2.590), biomass for cooking (compared with electricity, OR = 2.744, 95%CI:1.429-5.271), biomass (compared with centralized heat supply, OR = 1.229, 95%CI:0.120-12.546)and coal (compared with centralized heat supply, OR = 4.661, 95%CI:0.474-45.840) for heating, respiratory diseases (OR = 3.594, 95%CI:2.738-4.716), combined with cardiovascular disease (OR = 1.370, 95%CI:1.058-1.776) were the risk factors of COPD in Heilongjiang province. CONCLUSION: Higher risk for COPD was related with sex, age, education level, cooking fuel, heating methods, respiratory diseases and combined with cardiovascular disease.