City In Southern China Research Articles

A ventilator that responds to outdoor conditions for ventilation and air filtration

Because of haze and fog in some countries, the outdoor air is polluted and cannot be directly drawn into rooms for ventilation. A ventilator with air filtration may be required. However, as outdoor particulate concentrations vary greatly with time, it is not ideal to operate high-efficiency particulate air (HEPA) filtration continually. This investigation proposed a ventilator with multiple modes of ventilation and air filtration. The ventilator could be switched between modes according to the outdoor and indoor air conditions. The ventilation rate and indoor particle concentrations in a test room equipped with the proposed ventilator were modelled by the EnergyPlus software program and validated with experimental data. The validated model was then used to evaluate indoor air quality and energy consumption in a hypothetical apartment located in each of five different climatic zones in China. The performance of the proposed ventilator was compared to that of a market-available outdoor air blower. It was found that to obtain the same acceptable indoor air quality, the necessary operating time for the proposed ventilator in the HEPA filtration mode was approximately 70% shorter than for the outdoor air blower, and the ventilator required approximately 30% less operating energy. In some southern cities in China, mechanically driven medium-efficiency filtration was sufficient to reduce the PM2.5 concentration to the acceptable level.

Pre- and Postcollapse Ground Deformation Revealed by SAR Interferometry: A Case Study of Foshan (China) Ground Collapse

On the evening of 7 February 2018, a deadly collapse of a metro tunnel under construction in the Southern China city of Foshan caused 11 deaths, 8 injuries, and 1 missing person. For disaster prevention and mitigation, the spatiotemporal ground deformations before and after the collapse event were derived from 55 Sentinel-1A synthetic aperture radar (SAR) images spanning from March 2017 to January 2019. The results showed that prominent ground subsidence in the shape of a funnel with a maximum rate of 42 mm/year was observed in the vicinity of the collapse area before the accident. After the accident, the area and magnitude of subsidence decreased compared with precollapse subsidence. This decrease is related to the progress of tunnel excavation and groundwater changes. In the temporal domain, continuous subsidence was observed over a year before and after the accident, and accelerated subsidence appeared one month before the collapse accident. Soft soil consolidation and tunnel-induced soil losses were the main reasons for the subsidence over the study area. The leakage of groundwater accounted for the collapse event. The leaked groundwater eroded the soil, resulting in the formation of an arched hole. The connection between the arched hole and the tunnel reduced the bearing capacity of the soil layer above the arched hole, triggering the collapse event. The findings provide scientific evidence for future collapse monitoring and early warning due to tunnel excavation.

Distribution patterns and sources of heavy metals in soils from an industry undeveloped city in Southern China

The accumulations of heavy metals in urban soils are derived from natural parent materials and complex anthropogenic emission sources. This paper investigated metal contamination in urban soils at an industry undeveloped city (Haikou) in southern China, an ideal place to quantitatively assess the contribution of metals from different sources. The concentrations of most heavy metals in the urban soils of Haikou were much lower than their guideline values and that of those from other big cities in China. In contrast, the chemical speciation of metals in this study was similar to those from other cities. The spatial distributions of heavy metals and principal component analysis (PCA) revealed that basaltic parent materials, traffic emissions, and coal combustion were the main factors controlling the distribution of metals in the soils. The Pb isotope signatures of the Haikou soils were greatly different from those of the Beijing and Shanghai soils, but similar to those of the Guangzhou soils, suggesting the common sources of Pb in southern China cities. The results of ternary mixing model of Pb isotopes showed that the contributions of Pb from natural background, coal combustion and traffic emission sources were 5.3–82.4% (mean: 39.7 ± 21.1%), 0–85.7% (mean: 25.5 ± 24.6%), and 1.9–64% (mean: 34.8 ± 22.9%), respectively. This suggests that traffic emission is still the most important anthropogenic source of Pb in Haikou.

Reflecting on COVID-19: The Hong Kong Experience of Flattening the Curve Without Lockdown.

Reflecting on COVID-19: The Hong Kong Experience of Flattening the Curve Without Lockdown.

Maternal residential greenness and congenital heart defects in infants: A large case-control study in Southern China

BackgroundProximity to greenness has shown protective effects on coronary heart diseases by limiting exposure to environmental hazards, encouraging physical activity, and reducing mental stress. However, no studies have previously evaluated the impacts of greenness on congenital heart defects (CHDs). We examined the association between maternal residential greenness and the risks of CHDs. MethodsWe conducted a case-control study (8042 children with major CHDs and 6887 controls without malformations) in 21 cities in Southern China, 2004 – 2016. CHDs cases were diagnosed and verified by obstetrician, pediatrician, or pediatric cardiologists, within one year. We estimated maternal residential greenness using satellite-derived normalized difference vegetation index (NDVI) in zones of 500 meters (m) and 1000 m surrounding participants’ residences. Logistic regression models were used to assess NDVI-CHD relationships adjusting for confounders. ResultsInterquartile range NDVI increases within 500 m or 1000 m were associated with odds ratios (OR) of 0.95 (95% confidence interval (CI): 0.92, 0.98) and 0.94 (95%CI: 0.91, 0.97) for total CHDs respectively. Air pollutants mediated 52.1% of the association. We also identified a protective threshold at 0.21 NDVI on CHD. Similar protective effects from greenness were found in most CHDs subtypes. The protective associations were stronger for fall, urban or permanent residents, higher household income maternal age ≤35 years of age, and high maternal education (ORs: ranged from 0.85 to 0.96). ConclusionOur findings suggest a beneficial effect of maternal residential greenness on CHDs. Further studies are needed to confirm our findings, which will help to refine preventive health and urban design strategies.

Seasonal occurrence of N-nitrosamines and their association with dissolved organic matter in full-scale drinking water systems: Determination by LC-MS and EEM-PARAFAC

N-nitrosamines have been identified as emerging contaminants with tremendous carcinogenic potential for human beings. This study examined the seasonal changes in the occurrence of N-nitrosamines and N-nitrosodimethylamine formation potential (NDMA-FP) in drinking water resources and potable water from 10 drinking water treatment plants in a southern city of China. The changes in N-nitrosamines are well correlated with dissolved organic matter (DOM), particularly fluorophores, which were measured and compared between traditional fluorescence indices and excitation-emission matrix coupled with parallel factor analysis (EEM-PARAFAC). Four of N-nitrosamine species including N-nitrosodimethylamine (NDMA), N-Nitrosodibutylamine (NDBA), N-Nitrosopyrrolidine (NPYR), and N-Nitrosodiphenylamine (NDPhA) are found to be abundant compounds with an average of 29.5% (26.7%), 20.0% (25.2%), 18.9% (16.0%), and 9.0% (9.9%) in the source (and treated) water, respectively. The sum of N-nitrosamines concentration is recorded to be low in the wet season (July–September), whereas the dry season (October–December) provided opposite impacts. EEM-PARAFAC modeling indicated the predominance of humic-like component (C1) in the wet season while in the dry season the water was dominant in protein-like component (C2). All the N-nitrosamines excluding NDPhA and N-Nitrosomorpholine (NMOR) showed a strong association with protein-like component (C2). In contrast, humic-like C1, which was directly influenced by rainfall, was found to be a suitable proxy for NMOR and NDPhA. The results of this study are valuable to understand the correlation between different N-nitrosamines and DOM through adopting fluorescence signatures.

Dynamic Trends of Urban Flooding Mitigation Services in Shenzhen, China

Urbanization is characterized by population agglomeration and the expansion of impervious land surfaces. As a result of ongoing urbanization, rain and flood events have increasingly affected the well-being of residents in cities across the world. This should draw attention to the role of urban ecosystems in providing runoff retention/flood mitigation services. Focusing on Shenzhen, a major city in southern China, we used a hydrologic model based on the Soil Conservation Service curve number (SCS-CN) model to evaluate this flood reduction ecosystem service and its dynamic trends based on long-term remote sensing data from 1980 to 2018. We find that Shenzhen’s capacity for flood reduction gradually decreased due to changes in land use. The spatial distribution showed strong reduction capacity in the eastern part of the city and weak capacity in the western part. Additionally, the city’s total flood reduction capacity decreased by over 1.88 × 108 m3 over the past two decades. This loss of ecosystem-based flood reduction capacity undermines Shenzhen’s resilience against extreme weather events. Due to climate change, Shenzhen should advance its plan to build a “Sponge City” rooted in the conservation, restoration, and construction of urban ecological spaces.

Estimating the prevalence of hepatitis B by wastewater-based epidemiology in 19 cities in China

China has the world's largest burden of Hepatitis B virus (HBV) infection, with 86 million HBV carriers, including 32 million chronic Hepatitis B patients. To monitor the HBV prevalence in near real-time, a wastewater-based epidemiology (WBE) method by using lamivudine as a biomarker was conducted in 19 cities in the Southern part of China. LC-MS/MS was utilized to quantify lamivudine in sewage, and satisfactory method validation results were achieved. The average concentration of lamivudine in sewage was 156.4 ± 107.1 ng/L, and the daily consumption was 30.1 ± 19.8 mg/day/1000inh in average ranging from 0.4 to 105.5 mg/day/1000inh. The prevalence of chronic Hepatitis B was estimated to be 2.5% ± 1.7% based on the prevalence of lamivudine usage, which was 0.035% ± 0.023%. Besides, the estimated HBV prevalence in population aged over 15 years in 19 cities was 6.8% ± 4.5% and was consistent with the previous statistical data of 7% in 2018. This research demonstrated that the estimation of HBV prevalence by WBE with lamivudine as a biomarker is feasible in big cities in Southern China.

Impact of residential building heating on natural gas consumption in the south of China: Taking Wuhan city as example

Abstract With the development of social economy, heating in the south of China has been concerned widely. As one of the energy sources of decentralized heating, natural gas (NG) has been used more and more popularly. This paper aimed to study the impact of residential building heating on NG consumption, and took Wuhan city, the representative city needing heating in winter of the south of China due to its location and climate, as an example. Firstly, a typical residential building model was established through DeST software. The heating load was simulated, and the corresponding NG consumption index was calculated. Secondly, appropriate methods were used to forecast the basic data of Wuhan city in 2020, including households and per capita gross national product (GDP), etc. Thirdly, the NG consumption of residential buildings with and without heating were predicted. Finally, the impact of residential building heating on NG consumption was analyzed. The results showed that the average annual household heating consumption of residential building in Wuhan city in 2020 was 2100 kWh/ household, and the NG consumption using for residential building heating was 295 Nm3/household. In addition, the NG consumption of residential building generated by space heating with 100% heating rate was 2.82 times the NG consumption generated by the stove and water heater, showing that residential building heating had a large impact on NG consumption. This study can contribute to choosing appropriate heating method in the southern cities of China, and further planning the gas pipe network in these cities.

Comparing water footprint and water scarcity footprint of energy demand in China’s six megacities

Water is required throughout the life-cycle processes of energy production to meet the growing energy demands in China’s megacities. However, the spatially explicit impact on water scarcity both inside and outside the megacity boundaries from megacities’ energy demands remains unknown. We quantified and compared the water footprint and water scarcity footprint for final energy demand (WFE and WSFE) in China’s megacities from a consumption perspective. Six acknowledged megacities, i.e. Beijing, Tianjin, Shanghai, Chongqing, Shenzhen and Guangzhou, were evaluated with an extended multi-region input–output model. The results showed that these megacities were endowed with only 2.60% of the national available water resources, but their WFE (WSFE) made up nearly 14.00% (13.50%) of the national total. The megacities located in Northern China generated a larger WSFE in their WFE than the cities in Southern China. Energy demands in these megacities were heavily dependent on scarce water sourced from beyond their administrative boundaries, together importing 84.10% of WSFE from elsewhere. Electricity demand dominated the volumetric water consumption, representing 52.00% of the WFE. The distribution was different for scarce water consumption, with coal demand generating 34.00% of total WSFE, followed by electricity (31.00%) and petroleum (26.00%). Although Northern China is faced with dire water scarcity, its scarce water is still being predominantly outsourced to support energy demands in both Northern and Southern megacities, mainly due to their coal and petroleum reserves. Location-specific pathways and foci should be applied for different megacities to decouple their energy demands and their scarce water consumption.

Impact of contact tracing on SARS-CoV-2 transmission

As the far-reaching impacts of the coronavirus disease 2019 (COVID-19) pandemic expand to more and more countries, key questions about transmission dynamics and optimal intervention strategies remain unanswered. In particular, the age profile of susceptibility and infectivity, the frequency of super-spreading events, the amount of transmission in the household, and the contribution of asymptomatic individuals to transmission remain debated. The study by Qifang Bi and colleagues1 in The Lancet Infectious Diseases explores some of these questions by analysing detailed contact tracing data from Shenzhen, a large and affluent city in southern China at the border with Hong Kong.

Assessment of the impact of climate change on cities livability in China

As global warming worsens, climatic conditions in many regions are undergoing profound change, which could influence certain industries, such as agriculture and transportation, and affect the livability of cities. In this study, cities statistics and meteorological station data of the past decade in China were used to analyze the effect of climate change on cities livability. The livability of 288 Chinese cities during 2006–2016 was assessed using an analytic hierarchy process method. Results showed the mean cities livability index in China has improved about 12% throughout the past decade. Moreover, the Moran's I statistic and local indicators of spatial association revealed that the distribution of cities livability reflects a trend of gradual spatial agglomeration. In addition, geostatistical analysis was used to evaluate the impact of extreme weather events on cities livability. It was established that heatwaves and extreme precipitation events have significant impact on the livability of cities in southern China, whereas freezing weather drives the change of urban livability in northern areas. Combinations of different extreme weather conditions will have greater impact on urban livability. Based on mobile phone user data, the relationship between livability change and climate change in Chinese cities was elucidated to provide reference for urban environmental management.

Professional quality of life as potential mediators of the association between anxiety and depression among Chinese health-care clinicians.

Building upon the tripartite model of anxiety and depression, the current study aims to examine mechanisms of comorbidity between anxiety and depression using the ProQOL (Professional Quality of Life; including the constructs of burnout, secondary traumatic stress, and compassion satisfaction) in a sample of Chinese health-care clinicians. A randomized cross-sectional survey was distributed to 1620 participants who were recruited from eight state-owned hospitals in a city in southern China between January and May 2017. A total of 1562 questionnaires were returned (a response rate of 96.4%). After the cases with more than 10% missing variables and multivariate outliers being removed, 1423 valid cases remained. Multiple mediator models were used for mediation analysis that was conducted using the PROCESS v3.1 macro for SPSS. The indirect effects of anxiety upon depression through burnout (a1 = . 601 (95% confidence interval (CI): .552, .650), p < .001; b1 = .137 (95% CI: .101, .174), p < .001) and compassion satisfaction (a3= -.297 (95% CI: -.352, -.241), p < .001; b3 = -.069 (95% CI: -.100, -.039), p < .001) were significant, while there was no evidence that anxiety influenced depression by changing secondary traumatic stress. The indirect effects of depression upon anxiety through secondary traumatic stress (a2 = . 535 (95% CI: .483, .588), p < .001); b2 = .154 (95% CI: .120, .188), p < .001) were both positive and significant, while there was no evidence that depression influenced anxiety by changing burnout and compassion satisfaction. In the current sample, burnout and compassion satisfaction mediated the effect of anxiety upon depression and secondary traumatic stress mediated the effect of depression upon anxiety. The findings of the current study offer support to the tripartite model.

Efficient detection and assessment of human exposure to trace antibiotic residues in drinking water

Human exposure to antibiotic residues in drinking water has not been well evaluated. This study is the first attempt to simultaneously and efficiently identify and quantify 92 antibiotic residues in filtered tap water (multistage filtration at the tap) (n = 36) collected from 10 areas of a large city in southern China, 10 Chinese brands of bottled/barreled water (n = 30) and six foreign brands of bottled water (n = 18) obtained from the Chinese market. The average and median concentrations of all the detected antibiotic compounds was 182 and 92 ng/L in filtered tap water, 180 and 105 ng/L in Chinese brands of bottled/barreled water, and 666 and 146 ng/L in foreign brands of bottled water, respectively. A total of 58 antibiotics were detected in the filtered tap water, and 45 and 36 antibiotics were detected in the Chinese and foreign brands of bottled water, respectively. More types of antibiotics were detected in Chinese brands of bottled water than in the other bottled waters. In addition, Chinese waters had high roxithromycin concentrations, while the foreign brands of bottled water had high concentrations of dicloxacillin. The average and median values of the estimated overall daily intake of all the detected antibiotics were 4.3 and 2.3 ng/kg/day when only filtered tap water was drunk, 4.0 and 2.5 ng/kg/day when Chinese brands of bottled water was drunk, and 16.0 and 4.9 ng/kg/day when foreign brands of bottled water was drunk. Further study is needed to develop a more comprehensive estimation of human exposure to antibiotic residues in the environment and a more in-depth understanding of the potential hazard of ingested antibiotic residues to the human microbiome.

Sub-type source profiles of fine particles for fugitive dust and accumulative health risks of heavy metals: a case study in a fast-developing city of China.

Sub-type source profiles for atmospheric fine particle (PM2.5) were still scare in China, which limited the accurate source identification of it. Fugitive dust (including road dust, soil dust, resuspended dust, and construction dust, etc.) was one type of the most important contributors to PM2.5 and its associated toxic metals held potential threaten to human health. The chemical compositions, sources, and health risks of sub-type fugitive dust deserved an investigation for further accurate control of particles and alleviating human health risks. A total of sixty-five fugitive dust samples were collected in Suzhou, a fast-developing city in southern China, including eleven sub-types of road dust (overpass, main street, collector street, and ordinary street), soil dust (farmland and tree lawn), resuspended dust (site types were corresponding to those of road dust), and construction dust (large construction sites). Chemical analysis of water-soluble ions, elements, and carbonaceous components was carried out to establish the sub-type source profiles of PM2.5 for fugitive dust. Results showed that crustal elements were the most abundant components of fugitive dust, and soil dust was less polluted by anthropogenic activities. High contents of OC and low contents of EC were found in all the eleven types of dust. Equivalent ratios of anions and cations indicated that the fugitive dust was obviously alkaline. The contents of OC and EC in the four types of road dust were higher than those in other types of dust, while there existed differences among the sub-types of road dust. The NO3-/SO42- ratios (0.03-0.09) implied that coal-burning and motor vehicle emission co-existed in Suzhou. Coefficient divergence (CD) values of eleven sub-type source profiles showed that there were certain differences among them, which suggested the possibility of sub-type source identification. Cluster analysis indicated the heavy metals in fugitive dust were mainly from crustal materials, metallurgical manufacturing, vehicle emissions, and industrial activities. The enrichment degree of heavy metals for the four types of road dust was also inconsistent. Heavy metals in road dust and soil dust posed a non-carcinogenic risk to children through direct ingestion, and the non-carcinogenic risk of direct intake of heavy metals was much higher than that of respiratory and skin contact. It was found that the accumulative health risks of heavy metals were higher in densely populated areas, traffic intensive areas, and industrial areas through the spatial analysis. This study firstly discussed the chemical compositions of PM2.5 for eleven sub-types of fugitive dust in a Chinese city and assessed the accumulative health risks of heavy metals, which could be a demonstration for further related researches.

Molecular epidemiology and hematologic characterization of \u03b4\u03b2-thalassemia and hereditary persistence of fetal hemoglobin in 125,661 families of greater Guangzhou area, the metropolis of southern China

BackgroundIndividuals with δβ-thalassemia/HPFH and β-thalassemia usually present with intermedia or thalassemia major. No large-scale survey on HPFH/δβ-thalassemia in southern China has been reported to date. The purpose of this study was to examine the molecular epidemiology and hematologic characteristics of these disorders in Guangzhou, the largest city in Southern China, to offer advice for thalassemia screening programs and genetic counseling.MethodsA total of 125,661 couples participated in pregestational thalassemia screening. 654 subjects with fetal hemoglobin (HbF) level ≥ 5% were selected for further investigation. Gap-PCR combined with Multiplex ligation dependent probe amplification (MLPA) was used to screen for β-globin gene cluster deletions. Gene sequencing for the promoter region of HBG1 /HBG2 gene was performed for all those subjects.ResultsA total of 654 individuals had hemoglobin (HbF) levels≥5, and 0.12% of the couples were found to be heterozygous for HPFH/δβ-thalassemia, including Chinese Gγ (Aγδβ)0-thal, Southeast Asia HPFH (SEA-HPFH), Taiwanese deletion and Hb Lepore–Boston–Washington. The highest prevalence was observed in the Huadu district and the lowest in the Nansha district. Three cases were identified as carrying β-globin gene cluster deletions, which had not been previously reported. Two at-risk couples (0.0015%) were required to receive prenatal diagnosis. We also found 55cases of nondeletional-HPFH (nd-HPFH), including 54 with Italian nd-HPFH and one with the Aγ-197C-T heterozygous state. It is difficult to discriminate between Chinese Gγ (Aγδβ)0-thal and Italian nd-HPFH carriers using hemoglobin (Hb) analysis.ConclusionsThis study is the first to describe the familial prevalence of HPFH/δβ-thalassemia and the high-risk rate in Greater Guangzhou Area, and the findings will support the implementation of thalassemia screening for three common deletions by gap-PCR. We also presented a systematic description of genotype-phenotype relationships which will be useful for genetic counseling and prenatal diagnostic services for β-thalassemia intermedia.

Anal human papillomavirus among men who have sex with men in three metropolitan cities in southern China: implications for HPV vaccination

IntroductionMen who have sex with men (MSM), especially those infected with human immunodeficiency virus (HIV), are at disproportionate risk for human papillomavirus (HPV) infection. Data about anal HPV prevalence among MSM in southern China are limited. MethodsMSM were recruited between January 1 and August 31, 2017 in three metropolitan cities: Guangzhou, Shenzhen and Wuxi. A self-completed tablet-based questionnaire was used to collect information about socio-demographic/sexual behavioral characteristics, history of sexually transmitted infections (STIs) and recreational drug use. An anal brush was used to collect exfoliated cells for HPV DNA testing and genotyping, and a blood sample was taken for HIV testing. Penile/anal warts were checked by a clinician. ResultsA total of 536 MSM were enrolled, including 39 HIV-positive and 497 HIV-negative individuals. Compared with HIV-negative MSM, prevalence of any HPV genotype (79.5% vs 46.7%), any high-risk genotype (64.1% vs 36.6%) and any nonavalent vaccine-preventable genotype (53.9% vs 31.6%) was significantly higher in HIV-positive MSM, with all P < 0.01. HIV infection (adjusted odds ratio [AOR], 4.28; 95% confidence interval [CI], 1.87–9.80), using recreational drugs (AOR, 1.87; 95% CI, 1.22–2.87), having ≥ 3 years of sexual experience (AOR, 1.52; 95% CI, 1.01–2.28), having ≥ 6 lifetime male partners (AOR, 1.92; 95% CI, 1.29–2.86), and engaging receptive anal intercourse (AOR, 2.30; 95% CI, 1.48–3.57) were associated with higher anal HPV prevalence. Any HPV prevalence increased with age, from 24.5% at < 20 years to 55.8% at ≥ 40 years. ConclusionsAnal HPV prevalence was high among MSM in southern China, significantly associated with HIV status and sexual experience. HPV prevalence increased with age among MSM. A targeted HPV vaccination program for teenage MSM might be necessary. Our findings will inform targeted HPV modelling among MSM in China.

Long-Term Survival After Nasopharyngeal Carcinoma Treatment in a Local Prefecture-Level Hospital in Southern China.

PurposeNPC is a malignant and invasive tumor with the incidence rate of 19/100,000 per year in Zhongshan City, a prefecture city in southern China. Long-term survival analysis on intensity-modulated radiotherapy (IMRT)-based treatment in local prefecture-level hospitals have not been investigated. We aimed to evaluate the 5-year clinical outcomes and prognostic factors of NPC treated with IMRT in Zhongshan City People’s Hospital (ZSPH), a prefecture-level hospital in South China.Patients and MethodsThe number of 149 newly diagnosed non-metastatic NPC cases treated with IMRT were included from Zhongshan City People’s Hospital between January 2010 and December 2011. The survival outcomes, treatment toxicities and prognostic factors were analyzed by Kaplan-Meier method and Cox proportional hazards model.ResultsWith a median follow-up period of 65 months for the cohort, the 5-year local recurrence-free survival (LRFS), regional recurrence-free survival (RRFS) and distant metastasis-free survival (DMFS) and overall survival (OS) were 86.80%, 94.80%, 86.10% and 80.50%, respectively. The 5-year OS rates were 100%, 95.2%, 87% and 67.2% for stage I, II, II and IVa-b, respectively (P=0.004). The 5-year LRFS rates were 97.2%, 96.0%, 90.4% and 72.0% for T1, T2, T3 and T4, respectively (P=0.001); the 5-year DMFS rates were 100% for T1, 96.8% for T2, 81.9% for T3 and 74.6% for T4 (P=0.022). A multivariate analysis revealed tumor stage as an independent prognostic factor for LRFS, DMFS and OS. No patients died from acute toxicities. Late toxicities were observed for 130 (87.2%) patients, and most late toxicities were graded I/II.ConclusionNPC treatment effect in a prefecture-level hospital in South China was comparable to international results and toxicities were tolerable. Tumour stage was an independent prognostic factor for survival outcome. More NPC survival data from local and remote places are needed.

Applicability, optimization and performance comparison of self-preheated solar collector/regenerator

In this paper, a self-preheated solar collector/regenerator (C/R) is proposed to conquer the anti-regeneration phenomenon of traditional solar C/R in order to increase its regeneration efficiency. Through numerical simulation, the applicability of the self-preheated C/R in Northern and Southern cities of China and parameter optimization as well as the performance comparisons with the traditional C/R are conducted. The research results show the self-preheated C/R has good applicability for the 24 cities chosen in China, but the length of collector section is selected in the optimum ranges. The optimal proportion of collector length in the southern China is in the range of 0.4–0.55 while it focusing on 0.35–0.5 in the northern China. In the optimization of parameters, the best flow-rates of air and solution for the unit area of C/R fall into the ranges of 50–100 kg/(m2·h) and 3–6 kg/(m2·h) respectively, and the height of C/R glazing should be maintained at 0.04–0.06 m for higher regeneration efficiency of the device. By comparing to the performance of traditional C/R, the self-preheated solar C/R has greater superiority at higher ambient relative humidity, lower solution temperature and higher solution concentration as well as lower solar radiation intensity. The increased extent can reach as much as 22% at ξin = 0.4 kg/kg. The total length of self-preheated C/R has an optimal value on the performance of device. All these results can provide guidance for performance analysis and application of the novel solar collector/regenerator.

Real-Road Driving and Fuel Consumption Characteristics of Public Buses in Southern China

In this paper, the annual data of 40 public buses fueled with diesel in four cities in southern China have been analyzed for investigating the driving and fuel consumption characteristics. Results showed that the best traffic condition and smoothest driving style were obtained in Fuzhou, which was exact opposite to the results in Wuhan. And the driving characteristics of each city was weakly affected by the season’s variation. The fuel consumption characteristics of the public buses in different cities were studied by the method based on VSP (Vehicle Specific Power) model, and the fuel consumption factors in different cities and seasons have been given. The main factors influenced the fuel consumption characteristics could be summarized by the variations of driving characteristics and air conditioning using. The high fuel consumption was concentrated in region with low vehicle velocity range of 0 ∼ 10 km/h, and the proportion of this vehicle range directly affected the average fuel consumption level. The effect of the air conditioning using on fuel consumption was especially obvious in summer and winter, and the using of air conditioning would increase about 10% of the total vehicle fuel consumption.