[Spatial Distribution and Sources of Heavy Metals in Soil of a Typical Lead-Zinc Mining Area, Yangshuo].

Taking a typical lead-zinc mining area in Yangshuo county, Guangxi as the research object, the contents of 10 metal elements (Cr, Mn, Ni, Cu, Zn, As, Cd, Sb, Hg, and Pb) in the surface soil of Sidihe River basin in Yangshuo were analyzed and determined. Pearson correlation analysis, principal component analysis (PCA), positive definite matrix factorization (PMF), and other methods were comprehensively used to quantitatively analyze their contributions and identify pollution sources. In total, 168 surface soil samples were collected across the study area. The mean concentrations of Zn, Cd, Hg, and Pb in the soils were higher than the National Environmental Quality Standards for Soils in China. The mean contents of Sb, Cd, Cu, Pb, and Zn were higher than their corresponding local background values by approximately 1.01, 5.50, 3.29, 9.11, and 10.67 times, respectively, indicating that heavy metals have been enriched in topsoil. The Igeo showed that the major pollutant element in the soils was Hg, followed by Pb, Zn, and Mn. Correlation analysis and principal component analysis showed that the sources of metal pollution in surface soil in the study area were complex and mainly from human activities. Cu, Zn, Cd, Sb, As, and Pb were mainly derived from mining activities; Hg, Cr, and Ni were controlled by soil parent material sources; and Mn and Cd were mainly derived from mining activities and agricultural activities. PMF model analysis results showed that the metal pollution sources in the surface soil were jointly affected by these three sources. Mining activities, natural sources, and a mixed source of mining activities and agricultural activities were the main sources of heavy metal pollution in the soils, accounting for 58.0%, 13.5%, and 28.6% of the total heavy metal accumulation, respectively. Ni, Cu, Zn, As, Sb, Hg, and Pb were derived mainly from mining activities. Cr, Ni, and Hg were mainly attributed to natural sources, such as soil parent materials and rainfall erosion (44.6%, 23.2%, and 21.0%, respectively), and Mn and Cd were associated with a mixed source of mining activities and agricultural activities (75.4% and 70.4%).

Cost-effectiveness of using protons for breast irradiation aiming at minimizing cardiotoxicity: A risk-stratification analysis.

Background: Incidental exposure of the heart to ionizing irradiation is associated with an increased risk of ischemic heart disease and subsequent fatality in patients with breast cancer after radiotherapy. Proton beam therapy can limit the heart dose in breast irradiation to a negligible level. However, compared with conventional photon modality, proton breast irradiation is more expensive. In this study, we performed cost-effectiveness analyses to identify the type of patients who would be more suitable for protons. Methods: A Markov decision model was designed to evaluate the cost-effectiveness of protons vs. photons in reducing the risk of irradiation-related ischemic heart disease. A baseline evaluation was performed on a 50-year-old woman patient without the preexisting cardiac risk factor. Furthermore, risk-stratification analyses for photon mean heart dose and preexisting cardiac risk were conducted on 40-, 50-, and 60-year-old women patients under different proton cost and willingness-to-pay (WTP) settings. Results: Using the baseline settings, the incremental effectiveness (protons vs. photons) increased from 0.043 quality-adjusted life-year (QALY) to 0.964 QALY when preexisting cardiac risk increased to 10 times its baseline level. At a proton cost of 50,000 US dollars ($), protons could be cost-effective for ≤ 60-year-old patients with diabetes and ≤50-year-old patients with grade II-III hypertension at the WTP of China ($37,653/QALY); for ≤ 60-year-old patients with diabetes and ≤ 50-year-old patients with grade II-III hypertension or ≥ 2 major cardiac risk factors at a WTP of $50,000/QALY; and for ≤ 60-year-old patients with diabetes, grade II-III hypertension or ≥ 2 major cardiac risk factors and ≤ 50-year-old patients with total cholesterol ≥ 240 mg/dL at a WTP of $100,000/QALY. Conclusion: Patients' preexisting cardiac risk status was a key factor affecting the cardiac benefits gained from protons and should therefore be a major consideration for the clinical decision of using protons; cost-effective scenarios of protons exist in those patients with high risk of developing cardiac diseases.

Better preservation of erectile function in localized prostate cancer patients with modern proton therapy: Is it cost-effective?

BACKGROUND: Stereotactic body radiation therapy (SBRT) has gradually been recognized as favorable curative treatment for localized prostate cancer (PC). However, the high rate of erectile dysfunction (ED) after traditional photon-based SBRT remains an ongoing challenge that greatly impacts the quality of life of PC survivors. Modern proton therapy allows higher conformal SBRT delivery and has the potential to reduce ED occurrence but its cost-effectiveness remains uninvestigated. METHODS: A Markov decision model was designed to evaluate the cost-effectiveness of proton SBRT versus photon SBRT in reducing irradiation-related ED. Base-case evaluation was performed on a 66-year-old (median age of PC) localized PC patient with normal pretreatment erectile function. Further, stratified analyses were performed for different age groups (50, 55, 60, 65, 70, and 75 years) and threshold analyses were conducted to estimate cost-effective scenarios. A Chinese societal willingness-to-pay (WTP) threshold (37,653 US dollars [$])/quality-adjusted life-year [QALY]) was adopted. RESULTS: For the base case, protons provided an additional 0.152 QALY at an additional cost of $7233.4, and the incremental cost-effectiveness ratio was $47,456.5/QALY. Protons was cost-effective for patients ≤62-year-old at the WTP of China (≤66-year-old at a WTP of $50,000/QALY; ≤73-year-old at a WTP of $100,000/QALY). For patients at median age, once the current proton cost ($18,000) was reduced to ≤$16,505.7 or the patient had a life expectancy ≥88 years, protons were cost-effective at the WTP of China. CONCLUSIONS: Upon assumption-based modeling, the results of current study support the use of proton SBRT in younger localized PC patients who are previously potent, for better preservation of erectile function. The findings await further validation using data from future comparative clinical trials.

Intensity-modulated proton radiation therapy as a radical treatment modality for nasopharyngeal carcinoma in China: Cost-effectiveness analysis.

BACKGROUND: Compared to conventional intensity-modulated photon radiation therapy (IMRT), intensity-modulated proton radiation therapy (IMPT) has potential to reduce irradiation-induced late toxicities while maintaining excellent tumor control in patients with nasopharyngeal carcinoma (NPC). However, the relevant cost-effectiveness remains controversial. METHODS: A Markov decision tree analysis was performed under the assumption that IMPT offered normal tissue complication probability reduction (NTCP reduction) in long-term dysphagia, xerostomia, and hearing loss, compared to IMRT. Base-case evaluation was performed on T2N2M0 NPC of median age (43 years old). A Chinese societal willingness-to-pay threshold (33558 US dollars [$])/quality-adjusted life-year [QALY]) was adopted. RESULTS: For patients at median age and having NTCP reduction of 10%, 20%, 30%, 40%, 50%, and 60%, their incremental cost-effectiveness ratios were $102684.0/QALY, $43161.2/QALY, $24134.7/QALY, $13991.6/QALY, $8259.8/QALY, and $4436.1/QALY, respectively; IMPT should provide an NTCP reduction of ≥24% to be considered cost-effective. CONCLUSIONS: IMPT has potential to be cost-effective for average Chinese NPC patients and should be validated clinically.

Optimizing oropharyngeal cancer management by using proton beam therapy: trends of cost-effectiveness.

BACKGROUND: Proton beam therapy (PBT) is a new-emerging cancer treatment in China but its treatment costs are high and not yet covered by Chinese public medical insurance. The advanced form of PBT, intensity-modulated proton radiation therapy (IMPT), has been confirmed to reduce normal tissue complication probability (NTCP) as compared to conventional intensity-modulated photon-radiation therapy (IMRT) in patients with oropharyngeal cancer (OPC). Herein, we evaluated the cost-effectiveness and applicability of IMPT versus IMRT for OPC patients in China, aiming at guiding the proper use of PBT. METHODS: A 7-state Markov model was designed for analysis. Base-case evaluation was performed on a 56-year-old (median age of OPC in China) patient under the assumption that IMPT could provide a 25% NTCP-reduction in long-term symptomatic dysphagia and xerostomia. Model robustness was examined using probabilistic sensitivity analysis, cohort analysis, and tornado diagram. One-way sensitivity analyses were conducted to identify the cost-effective scenarios. IMPT was considered as cost-effective if the incremental cost-effectiveness ratio (ICER) was below the societal willingness-to-pay (WTP) threshold. RESULTS: Compared with IMRT, IMPT provided an extra 0.205 quality-adjusted life-year (QALY) at an additional cost of 34,926.6 US dollars ($), and had an ICER of $170,082.4/ QALY for the base case. At the current WTP of China ($33,558 / QALY) and a current IMPT treatment costs of $50,000, IMPT should provide a minimum NTCP-reduction of 47.5, 50.8, 55.6, 63.3 and 77.2% to be considered cost-effective for patient age levels of 10, 20, 30, 40 and 50-year-old, respectively. For patients at the median age level, reducing the current IMPT costs ($50,000) to a $30,000 level would make the minimum NTCP-reduction threshold for "cost-effective" decrease from 91.4 to 44.6%, at the current WTP of China (from 69.0 to 33.5%, at a WTP of $50,000 / QALY; and from 39.7 to 19.1%, at a WTP of $100,000 / QALY). CONCLUSIONS: Cost-effective scenarios of PBT exist in Chinese OPC patients at the current WTP of China. Considering a potential upcoming increase in PBT use in China, such cost-effective scenarios may further expand if a decrease of proton treatment costs occurs or an increase of WTP level.

Cost-effectiveness analysis of proton beam therapy for treatment decision making in paranasal sinus and nasal cavity cancers in China.

BACKGROUND: Cost-effectiveness is a pivotal consideration for clinical decision making of high-tech cancer treatment in developing countries. Intensity-modulated proton radiation therapy (IMPT, the advanced form of proton beam therapy) has been found to improve the prognosis of the patients with paranasal sinus and nasal cavity cancers compared with intensity-modulated photon-radiation therapy (IMRT). However, the cost-effectiveness of IMPT has not yet been fully evaluated. This study aimed at evaluating the cost-effectiveness of IMPT versus IMRT for treatment decision making of paranasal sinus and nasal cavity cancers in Chinese settings. METHODS: A 3-state Markov model was designed for cost-effectiveness analysis. A base case evaluation was performed on a patient of 47-year-old (median age of patients with paranasal sinus and nasal cavity cancers in China). Model robustness was examined by probabilistic sensitivity analysis, Markov cohort analysis and Tornado diagram. Cost-effective scenarios of IMPT were further identified by one-way sensitivity analyses and stratified analyses were performed for different age levels. The outcome measure of the model was the incremental cost-effectiveness ratio (ICER). A strategy was defined as cost-effective if the ICER was below the societal willingness-to-pay (WTP) threshold of China (30,828 US dollars ($) / quality-adjusted life year (QALY)). RESULTS: IMPT was identified as being cost-effective for the base case at the WTP of China, providing an extra 1.65 QALYs at an additional cost of $38,928.7 compared with IMRT, and had an ICER of $23,611.2 / QALY. Of note, cost-effective scenarios of IMPT only existed in the following independent conditions: probability of IMPT eradicating cancer ≥0.867; probability of IMRT eradicating cancer ≤0.764; or cost of IMPT ≤ $52,163.9. Stratified analyses for different age levels demonstrated that IMPT was more cost-effective in younger patients than older patients, and was cost-effective only in patients ≤56-year-old. CONCLUSIONS: Despite initially regarded as bearing high treatment cost, IMPT could still be cost-effective for patients with paranasal sinus and nasal cavity cancers in China. The tumor control superiority of IMPT over IMRT and the patient's age should be the principal considerations for clinical decision of prescribing this new irradiation technique.

Benzodipyrrole-2,6-dione-3,7-diylidenedimalononitrile Derivatives for Air-Stable n-Type Organic Field-Effect Transistors: Critical Role of N-Alkyl Substituent on Device Performance.

Benzodipyrrole-2,6-dione-3,7-diylidenedimalononitriles (BDPMs) were synthesized as active materials for the use in air-stable n-type organic field-effect transistors (OFETs), whose optical and electrochemical properties were examined. BDPM-based small molecules exhibit deep lowest unoccupied molecular orbital levels, which are required in air-stable n-type OFETs. An OFET device that was based on BDPM-But and fabricated by vapor deposition provided a maximum electron mobility of 0.131 cm2 V-1 s-1 under ambient conditions.

The relationship between psychosocial risk factors, burnout and quality of life among primary healthcare workers in rural Guangdong province: a cross-sectional study.

BACKGROUND: Healthcare workers are often exposed to stressful working conditions at work which affect their quality of life. The study investigated the relationship between psychosocial risk factors, stress, burnout, and quality of life among primary healthcare workers in general medical practice in Qingyuan and Chaozhou cities in Guangdong province. METHOD: The cross-sectional study was conducted in 108 primary health facilities including 36 community health centers (CHCs) across two developing cities in Guangdong province. A total of 873 healthcare workers completed the questionnaires. Quality of life was evaluated using The World Health Organization Quality of Life Questionnaire (WHOQOL-BREF) and psychological risk factors were evaluated by the Copenhagen Psychosocial Questionnaire (COPSOQ). General quality of life and the quality of life domains were transformed into a score range from minimum 0 to 100 maximum. Higher scores indicated better quality of life and vice versa. Significant associations were verified using multiple regression analysis. RESULTS: Poor quality of life was observed in 74.6% of healthcare workers surveyed. General poor quality of life was significantly higher among workers who reported higher burnout (Beta = - 0.331, p < 0.001). In addition, workers with high levels of burnout, unmarried workers and female workers had a higher possibility of physical health. A greater risk of poor psychological health was observed among workers with high burnout, poor sense of community and those with lower educational levels. Workers who lacked social support, those with fewer possibilities for development had increased probability of poor quality of life in the social domain. Poor quality of life in the environmental domain was observed among workers who were dissatisfied with their jobs and workers with low salaries. CONCLUSIONS: Primary healthcare workers in developing cities in China have a highly demanding and strained working environment and poor quality of life. Reducing job stress and improving work conditions may ultimately improve the well-being of primary healthcare workers.

Development and Validation of a Simplified Chinese Version of the Assessment Tool for Students' Perceptions of Medical Professionalism.

Professionalism is crucial in all professions and is particularly important in the medical field. Measuring students' perceptions of professionalism can help to form education targeting the enhancement of professionalism. This study aimed to validate an effective assessment tool for the measurement of medical students' perceptions of medical professionalism in mainland China. The cross-sectional survey was conducted in three medical colleges in Guangdong, China. Of the 2103 eligible medical students, 1976 responded, and 1856 questionnaires were deemed valid. Students from clinical medicine in these three medical colleges were randomly selected by cluster sampling. First, a Simplified Chinese Version questionnaire to measure Student's Perception of Medical Professionalism (SCV-SPMP) was constructed. Second, questionnaires from 1856 students majoring in clinical medicine at three medical colleges were included in the analysis. Third, exploratory factor analysis, Cronbach's alpha, item-subscale correlation, and confirmatory factor analysis were conducted to test the validity and reliability of the SCV-SPMP. Nine items were eliminated following exploratory factor analysis, and four subscales were extracted from the analysis. All internal consistency reliability exceeded the minimum standard. The overall Cronbach's alpha was 0.94, and four subscales' alphas were 0.82 (Accountability and excellence), 0.81 (Duty), 0.89 (Honor and integrity), and 0.85 (Practice habits and respect for others), respectively. The model fit was good. The convergent validity and discriminant validity were acceptable. The modified SCV-SPMP was found to be a valid and reliable tool to capture the main features of Chinese students' perceptions of medical professionalism in four dimensions, and it provides a quantitative method for the measurement of the students' perceptions in mainland China..

Factors Influencing the Emergency Medical Service Response Time for Cardiovascular Disease in Guangzhou, China.

While emergency medical service (EMS) response time (ERT) is a major factor associated with the survival of patients with cardiovascular disease (CVD), relatively few studies have explored the factors associated with ERT. This study aimed to assess the current status of ERT and to identify the factors affecting ERT in patients with CVD in China. Between January 1, 2011 and December 31, 2015, EMS responses to CVD incidents in Guangzhou, China, were examined. The primary outcome was ERT, defined as the time from receipt of an emergency call to the arrival of paramedics on the scene. Factors associated with ERT were evaluated by multivariable logistic regression. A total of 44 383 CVD incidents were analysed. The median ERT was 12.58 min (interquartile range=9.98-15.67). Among the risk factors, distance (OR=13.73, 95% CI=11.76-16.04), level of hospital (OR=1.57, 95% CI=1.40-1.75), and site of the incident (OR=1.53, 95% CI=1.38-1.69) were the top three significant factors affecting the ERT. Our results suggest that greater attention should be given to factors affecting the ERT. It is essential to make continuous efforts to promote the development of effective interventions to reduce the response time.

Comparison of three data mining models for predicting diabetes or prediabetes by risk factors.

The purpose of this study was to compare the performance of logistic regression, artificial neural networks (ANNs) and decision tree models for predicting diabetes or prediabetes using common risk factors. Participants came from two communities in Guangzhou, China; 735 patients confirmed to have diabetes or prediabetes and 752 normal controls were recruited. A standard questionnaire was administered to obtain information on demographic characteristics, family diabetes history, anthropometric measurements and lifestyle risk factors. Then we developed three predictive models using 12 input variables and one output variable from the questionnaire information; we evaluated the three models in terms of their accuracy, sensitivity and specificity. The logistic regression model achieved a classification accuracy of 76.13% with a sensitivity of 79.59% and a specificity of 72.74%. The ANN model reached a classification accuracy of 73.23% with a sensitivity of 82.18% and a specificity of 64.49%; and the decision tree (C5.0) achieved a classification accuracy of 77.87% with a sensitivity of 80.68% and specificity of 75.13%. The decision tree model (C5.0) had the best classification accuracy, followed by the logistic regression model, and the ANN gave the lowest accuracy.

[Observation on therapeutic effect of cervical spondylosis of vertebral artery type treated with both acupuncture and mild moxibustion].

OBJECTIVE: To observe the clinical therapeutic effects on cervical spondylosis of vertebral artery type treated with both acupuncture and mild moxibustion and investigate the mechanism of action. METHODS: Sixty cases were randomly divided into the combined therapy group of acupuncture and mild moxibustion (combined therapy group) and the acupuncture group, 30 cases for each group. In combined therapy group, Baihui (GV 20), Fengchi (GB 20) and cervical Jiaji (EX-B 2) were punctured, and Baihui(GV 20), Dazhui (GV 14), Mingmen (GV 4), Shenque (CV 8) and Guanyuan (CV 4) were treated with mild moxibustion; in acupuncture group, acupuncture was simply applied, the acupoints selection and manipulation were the same as those in the combined therapy group. The average velocity meter and the resistive index of vertebral and basal arteries were observed before and after treatment by TCD examination, the therapeutic effects and clinical symptom-sign scores were observed too. RESULTS: The total effective rate was 93.3% (28/30) in combined therapy group, and 73.3% (22/30) in acupuncture group. The therapeutic effect in combined therapy group was superior to that in acupuncture group (P < 0.05). The improvements of symptom-sign scores in two groups after treatment were more significant than that before treatment, and the score in the combined therapy group was superior to that in acupuncture group (P < 0.05). The average velocity meter and the resistive index of vertebral and basal arteries after treatment were improved in both groups, in which, the improvement in combined therapy group was more apparent (all P < 0.05). CONCLUSION: The therapeutic effects on cervical spondylosis of vertebral artery type treated with both acupuncture and mild moxibustion are preferable; by this therapy, the average velocity meter of vertebral and basal arteries are accelerated and the resistive index is decreased.