Guangzhou Province Research Articles

Member separation and deformation recognition of spatial grid structures in-service

Bending deformation of members in spatial grid structures is a typical damage threatening structural safety. Conventional methods of deformation measurement have difficulty in detection member selection, high-altitude operation, or systematic error elimination. And reverse modeling technology for deformation detection is mostly utilized in entire structures or laboratory scenes. In this study, two kinds of member separation algorithms are developed based on point cloud registration and point cloud features respectively, both of which are suitable for engineering situations of insufficient point cloud density and multiple noise sources. The deformation recognition algorithm for members is improved accordingly with double judgment conditions. A field test has been carried out in a Sports Center Stadium in Guangzhou province. 7045 members are identified, and 29 crooked members are eventually recognized. The results demonstrate that the proposed algorithms can improve the efficiency of member separation and deformation recognition, and assist the monitoring and assessment of spatial grid structures in-service.

The Impact of Design Thinking with Secondary Students in Shaoguan City Institute of Technicians, Guangzhou Province

The Impact of Design Thinking with Secondary Students in Shaoguan City Institute of Technicians, Guangzhou Province

Machine learning-based classification of woodland bitter vine (Mikania micrantha Kunth)

The woodland invasive species bitter vine (Mikania micrantha Kunth) is widely distributed in southern Asia. Since it adversely affects vegetation growth and ecological functions, it is imperative to develop an automated detection method to investigate the species’ expansion in large areas. We obtained training and test samples in the Zengcheng woodland, Guangzhou Province, China, and used aerial imagery to classify bitter vine using machine learning algorithms. The results suggested that visual interpretation was suitable for bitter vine classification but had slightly lower accuracy than methods using field-based training samples. The random forest (RF) algorithm proved most efficient for large-scale detection with the highest overall classification accuracy (99.62% for the test set and 99.92% for the training set) and Kappa coefficient (0.9878 for the test set and 0.9975 for the training set). Although the backpropagation neural network-based deep learning (DL) approach showed uncertainties and errors in this study, a more advanced DL method could be suitable for this task but requires further research. Bitter vine occurs predominantly in disturbed areas with low vegetation cover. Therefore, monitoring, silvicultural measures, and manual removal are necessary. Since bitter vine is highly distinguishable in images, future studies should further investigate supervised classification methods to map and monitor this species.

Synergistic Air Pollutants and GHG Reduction Effect of Commercial Vehicle Electrification in Guangdong’s Public Service Sector

This paper aims to analyze the associated environment and climate benefits of electrification by comparing the air pollutant and CO2 emissions from the fuel cycle of battery electric commercial vehicles (BECVs) and internal combustion engine commercial vehicles (ICECVs) through a case study in Guangzhou Province. Five types of vehicles (i.e., electric buses, coaches, light-duty trucks, dump trucks, and waste haulers) used in the public service sector were selected for analysis, taking into account six development scenarios based on the prevalent ownership trends of electric vehicles and the energy system optimization process. The results reveal that an increase in commercial vehicle electrification in the public service sector will cause reductions of 19.3 × 103 tons, 0.5 × 103 tons, 9.5 × 103 tons, and 8.5 × 106 tons for NOx, PM2.5, VOCs, and CO2, respectively, from the base 2030 case (CS_II, the electrification rates of buses, coaches, light-duty trucks, dump trucks, and waste haulers will reach 100%, 26.5%, 15.4%, 24.0%, and 33.1%, and their power needs will be met by 24% coal, 18.4% gas, and 13.2% renewable power), but with a slight increase in SO2 emissions. With the further penetration of BECVs into the market, the emission reduction benefits for NOx, PM2.5, VOCs, and CO2 could be even more remarkable. Moreover, the benefit obtained from the optimization of the share of renewable energy is more noticeable for CO2 reduction than for air pollutant reduction. Prioritizing the electrification of light-duty trucks after completing bus electrification could be a potential solution for achieving ozone pollution control and lowering carbon emissions in Guangdong. In addition, these results can provide scientific support for the formulation or adjustment of advanced pollution mitigation and peaking carbon policies in Guangdong, as well as other regions of China.

The Influences of Bladder Properties on the Working Performance of the Multibladder-Type Inflatable Anchor

Due to the high bearing capacity and better controllability of bladder parameters, the multibladder-type inflatable anchor shows a great application prospect in the engineering construction in soft soil areas. In this study, based on a soft soil foundation pit project in Guangzhou Province, China, the multibladder-type inflatable anchor was applied to the engineering practice for the first time, and the working characteristics of the multibladder-type inflatable anchor were analyzed and discussed through field experiments. Primarily, the optimization design and experimental facility of the multibladder-type inflatable anchor were introduced in detail to realize the refinement and perfection of the anchorage technological process. Besides, the influence degrees of the bladder number, diameter, thickness, space, and length on the bearing characteristics and deformation control of the anchor were studied by using the control variable method, as well as the influencing mechanisms. Subsequently, the advantages of the multibladder-type inflatable anchor were presented by comparing its anchoring efficacy with that of the traditional grouting anchor. Ultimately, the analysis results were used to verify the reliability of the multibladder-type inflatable anchor and provide the experimental basis for its popularization and application.

Studying the Growth Prediction Model of Eucalyptus Research based on Multivariate Statistical Analysis

Forests have ecological functions such as purifying the atmosphere, fixing carbon and releasing oxygen, conserving water sources, preventing wind and sand invading, and harbouring biodiversity. At the same time, they provide human beings with materials and energy, and thus are important for economic and societal development. However, in our national power grid system, trees might cause interference on power transformation lines. Furthermore, if these circumstances cannot be responded timely, huge economic losses would happen. Therefore, research of forest growth models can more accurately predict the growth and the dynamics of forests, as well as provide a reference for the power warning system. This study conducts a forecast simulation study on the growth of eucalyptus in Guangzhou province, China, proposes a multivariate statistical analysis to predict tree species growth, and then compares its performances with traditional Logistic model results. We found that our multivariate statistical model can effectively consider various environmental influencing factors, thus predict tree height excellently (R2=0.9776), so as provide new foundations for tree height prediction.

Epidemic-related sites in covid-19 media reports

Background: Since the outbreak of the COVID-19 virus in Wuhan, China, in early 2020, the Chinese government has formed a mode of information disclosure. More than 400 cities have announced specific location information for newly diagnosed cases of novel coronavirus pneumonia, including residential areas or places of stay. We have established a conditional random field model and a rule-dependent model based on Chinese geographical name elements. Taking Guangdong Province as an example, the identification of named entities and the automatic extraction of epidemic-related sites are carried out. This method will help locate the spread of the epidemic, prevent and control the spread of the epidemic, and gain more time for vaccine clinical trials. Methods: Based on the presentation form of the habitual place or place of stay of the diagnosed cases in the text of the web page, a conditional random field model is established, and a rule-dependent model is established according to the combination rule of the elements of the place words and the place name dictionary composed of provinces, cities and administrative regions. Findings: The results of the analysis based on the conditional random field model and the rule-dependent model show that the location of confirmed cases of new coronavirus pneumonia in Guangdong Province in mid-February is mainly concentrated in Guangzhou，Shenzhen，Zhuhai and Shantou Cities. In Guangzhou, Futian District has more epidemicsites and Huangpu and Conghua District have fewer epidemic sites. Government officials in Guangzhou City should pay attention to Futian District. Interpretation: Governments at all levels in Guangzhou Province have intervened to control the epidemic through various means in mid-February. According to the results of the model analysis, we believe that the administrative regions with more diagnosed locations should focus on and take measures such as blockades and control of personnel flow to control the disease in those administrative regions to avoid affecting other adjacent administrative regions.

FROM NATIVE TO OUTLANDER: EXPLORING INFORMAL COMMUNITY IN CHENGZHONGCUN OF CHINA

In the existing research on Chinese migration, rural domestic Chinese migrants are often portrayed as a community of intruders with a detached culture who invade a host destination city. Usually, as a first step, they settle down in a so-called “Chengzhongcun” (literally a village encircled by the city boundaries, hereafter CZC), which is a kind of “urban village”, or an undeveloped part of a city that is overshadowed by the more developed areas. The present paper tries to give an image of the rural-to-urban migrants as a more vigorous mediator that forms their migration destination. The aims are the following: first, to achieve a detailed written analysis of an existing CZC community and its functioning as a mirror of the discriminating division between the rural and urban life in China. Secondly, by taking into account the experiences of migrant communities in their host cities, this paper seeks to highlight the migrants' emotional conflict and increasing loss of values that occurs in the migration process from the rural to the urban. Thirdly, the migrants' household survival strategies shall be explored. Finally, weaving these strands together, this paper presents a case study of a Tulou collective housing project in Guangzhou Province, China.

More Information on Risk Factors for SARS-CoV-2 Transmission

In Guangzhou Province, China, 391 COVID-19 cases were identified between January 13 and March 6, 2020, via surveillance testing (3.7%), symptomatic

Nonparaxial propagation of radially polarized chirped Airy beams in uniaxial crystal orthogonal to the optical axis* *Projected supported by the National Natural Science Foundation of China (Grant Nos. 11775083 and 11374108), the Science and Technology Program of Guangzhou Province, China (Grant No. 2019050001), and the Special Funds for the Cultivation of Guangdong College Students’ Scientific and Technological Innovation, China (Grant

The nonparaxial propagation of radially polarized chirped Airy beams (RPCAiBs) in uniaxial crystal orthogonal to the optical axis is analytically studied. The effects of the first and the second order chirp factors, and the ratio of the extraordinary refractive index to the ordinary refractive index on the nonparaxial evolution of RPCAiBs in different observation planes are investigated in detail. The results show that when one parameter changes, different components behave differently, and even the same component has various behavior in different directions. The initial slope of RPCAiBs in the x-direction varies more with the first order chirp factor than that in the y-direction. Meanwhile, with the second order chirp factor becoming larger, the depth of the focus of the y-component in the x-direction decreases while that in the y-direction has no difference. In addition, the different ratios of the extraordinary refractive index to the ordinary refractive index change the difference of the depth of the focus between the x- and the y-components.

Genetic characterisation of a complex class 1 integron in an NDM-1-producing Citrobacter freundii ST396 clinical strain isolated from a urine sample

ObjectivesThe aim of this study was to characterise a multidrug-resistant (MDR) Citrobacter freundii strain carrying a blaNDM-1-harbouring conjugative IncA/C2-type plasmid in China. MethodsThe whole genome of C. freundii strain L75 was sequenced both on HiSeq® (Novogene Corp., China) and GridION X5 (GrandOmics Biosciences Co., Ltd.) platforms. De novo genome assembly, genome annotation, multilocus sequence typing (MLST) and plasmid replicon typing were performed. ResultsCitrobacter freundii L75 was assigned to ST396 and contains a 5.1-Mb chromosome and two plasmids (∼146 kb and ∼73 kb) designated pCf75 and pCf76, respectively. The antibiotic resistance determinants blaNDM-1, sul1, sul2, arr-3, mph(A), aadA16, aph(3”)-Ib, aac(3)-IId, aph(6)-Id, aac(6')-Ib-cr and dfrA27 were located on plasmid pCf75, whilst blaCMY-78 was chromosomally encoded. A 22.1-kb MDR-encoding region (MDRR) in a complex class 1 integron contained all of the resistance genes of plasmid pCf75. ConclusionsWe detected and characterised a plasmid carrying a novel MDRR in which a complex class 1 integron plays an essential role. In addition, this study provides fresh genomic insights into the diversity of C. freundii ST396 prevalent in Guangzhou Province, China, and underscores the increasing clinical relevance of the IncA/C2 plasmid family.

Phytoplankton diversity and community responses to physicochemical variables in mangrove zones of Guangzhou Province, China.

The phytoplankton diversity and community response to physicochemical variables in mangrove zones of Guangdong Province along the South China coast was investigated from October to December, 2017. This study was set to investigate the phytoplankton community structure in the mangrove zone and assess the relationship between the physicochemical variables and phytoplankton species diversity. Physicochemical variables such as water temperature, total dissolve solids (tds), pH, salinity, turbidity, electrical conductivity (EC) and nutrient salts were measured in situ across the 27 stations. A total of 451 species of phytoplankton were identified belonging to 10 groups (Bacillariophta > Cyanophyta > Chlorophyta > Euglenophyta > Dinoflagellate > Eubacteria > Ochrophyta > Crytophyta > Rhodophyta > Charophyta) and quantified to constitute a standing crop of 7.11 × 108 cells dm-3. The principal component analysis (PCA) reveals that reactive nitrate, phosphate, electrical conductive (EC) and turbidity were the best abiotic factors that controlled the phytoplankton community structure in the area. However, Cannon Corresponding Analysis and Pearson correlation have explicitly revealed the impact of reactive nitrate, phosphate, EC and turbidity on the phytoplankton community structure. For instance, the CCA ordination revealed that species richness and evenness were positively influenced by reactive nitrate but negatively affected by EC, turbidity and water temperature. Diatoms were mostly controlled by total dissolved solids (tds) and salinity, whereas Euglena, cyanobacteria and green algae were impacted EC and turbidity, apart from the general contribution of the nutrient salts as delineated by CCA ordination. The Shannon diversity index value exposed different levels of organic pollution across the mangrove zone of which GD37 was the most impacted station.

Mothers Left without a Man: Poverty and Single Parenthood in China

Most single-parent families in China are headed by women, and single mothers represent one of the fastest-growing groups living in poverty. Yet few studies have examined this group. This article seeks to better understand how (and why) single mothers are disadvantaged in China. Based on in-depth interviews conducted in Zhuhai, Guangzhou Province, it demonstrates that single mothers are left behind in four respects: lower income and worse economic conditions, lower employment and career development opportunities, worse physical and mental health, and poorer interpersonal relationships and less chance of remarriage. The causes of these disadvantages include Chinese family beliefs, a culture of maternal sacrifice, the traditional division of labour between men and women and social stereotypes about single mothers. The article highlights the impacts of Chinese familism culture on single mothers and advocates incorporating a gender perspective into the agenda of family policy and other relevant social policies in China.

Research advances on characteristics, damage and control measures of weedy rice

<p indent=0mm>Weedy rice (<italic>Oryza sativa </italic>f.<italic> spontanea</italic>) presumably originated from rice but has weedy characteristics. It is one of the malignant weeds in rice field that decreases rice production and grain quality severely. In this study, the biological characteristics of weedy rice were described from morphology, shattering, dormancy and stress tolerance. The process of weedy rice origination from de-domestication of cultivated rice was summarized briefly. We also introduced the worldwide distribution of weedy rice as well as its non-uniform distribution in China with the most severe occurrence in middle-south area of Jiangsu province and Zhanjiang of Guangzhou province. In addition, we analyzed the agricultural damage on rice yield, rice quality and paddy field ecology environment by weedy rice. To control the occurrence and spread of weedy rice, we further proposed comprehensive measures, including prevention and controlling measures, reasonable cultivation system, and scientific use of chemical herbicides.

STUDY ON THE WATER BODY EXTRACTION USING GF-1 DATA BASED ON ADABOOST INTEGRATED LEARNING ALGORITHM

Abstract. Surface water system is an important part of global ecosystem, and the changes in surface water may lead to disasters, such as drought, waterlog, and water-borne diseases. The rapid development of remote sensing technology has supplied better strategies for water bodies extraction and further monitoring. In this study, AdaBoost and Random Forest (RF), two typical algorithms in integrated learning, were applied to extract water bodies in Chaozhou area (mainly located in Guangzhou Province, China) based on GF-1 data, and the Decision Tree (DT) was used for comparative tests to comprehensively evaluate the performance of classification algorithms listed above for surface water body extraction. The results showed that: (1) Compared with visual interpretation, AdaBoost performed better than RF in the extraction of several typical water bodies, such as rivers, lakes and ponds Moreover, the water extraction results of the strong classifiers using AdaBoost or RF were better than the weak basic classifiers. (2) For the quantitative accuracy statistics, the overall accuracy (96.5%) and kappa coefficient (93%) using AdaBoost exceeded those using RF (5.3% and 10.6%), respectively. The classification time of AdaBoost increased by 403 seconds and 918 seconds relative to RF and DT methods. However, in terms of visual interpretation, quantitative statistical accuracy and classification time, AdaBoost algorithm was more suitable for the water body extraction. (3) For the sample proportion comparison experiment of AdaBoost, four sampling proportions (0.1%, 0.2%, 1% and 2%) were chosen and 0.1% sampling proportion reached the optimum classification accuracy (93.9%) and kappa coefficient (87.8%).

Assessment of dicarbonyl contributions to secondary organic aerosols over China using RAMS-CMAQ

Abstract. The concentration of secondary organic aerosol (SOA) is underestimated in current model studies. Recent research suggests that the reactive uptake of dicarbonyls contributes to the production of SOA, although few models have included this pathway. Glyoxal, an important representative component of dicarbonyls in models, is significantly underestimated. We therefore incorporated the reactive uptake of dicarbonyls into the regional air quality modeling system RAMS-CMAQ (the Regional Atmospheric Modeling System-Community Multiscale Air Quality) to evaluate the contribution of dicarbonyls to SOA, and we then assess the impact of the underestimation of glyoxal on the production of SOA in China during two time periods: 3 June to 11 July 2014 (episode 1) and 14 October to 14 November 2014 (episode 2). When the reactive uptake process was added, the modeled mean concentration of SOA in episode 1 increased by 3.65 µg m−3, which explained 34.8 % of the unaccounted-for source of SOA. Meanwhile the increase in the concentration of SOA in episode 2 was 1.82 µg m−3 as a result of the lower liquid water content and the lower amount of dicarbonyls produced from biogenic precursors in the fall. On this basis, when the glyoxal simulation was improved, the modeled mean dicarbonyl-derived SOA (AAQ) increased by more than a factor of 2 in both episodes relative to case 1. AAQ in episode 1 contributed, on average, 60.6 % of the total concentration of SOA and the increase in this contribution represented 69.1 % of the unaccounted-for concentration of SOA, whereas the mean AAQ in episode 2 accounted for 64.5 % of total concentration of SOA. Based on the results, the mean AAQ over China was generally higher in the east than in the west during the two episodes. The highest value (10–15 µg m−3) of episode 1 appeared in the areas around the lower reaches of the Yellow River, whereas the highest value of 5–10 µg m−3 in episode 2 was concentrated over regions from south of the lower reaches of the Yellow River to the south of Guangzhou Province as well as the Sichuan Basin. The contribution of AAQ to the concentration of SOA in episode 1 varied from 10 % to 90 % throughout China, with the highest contributions (70 %–90 %) in the coastal regions and offshore along the East China Sea to the South China Sea and in the southwestern regions. The fraction of AAQ to SOA in episode 2 was in the range of 10 %–80 % over China, with the fraction up to 80 % in a small portion of northeastern China.

Explicit cost-risk tradeoff for renewable portfolio standard constrained regional power system expansion: A case study of Guangdong Province, China

In this paper, a risk explicit interval two-stage programming (REITSP) model was proposed for supporting the regional electricity generation expansion with renewable portfolio standard (RPS) constraint. It could effectively tackle multiple uncertainties expressed as interval numbers. But unlike the traditional interval two-stage programming model, the proposed REITSP model could provide an explicit trade-off information between system cost and risk for decision makers with different risk preferences. It could minimize the total system cost, as well as the decision risk according to the aspiration risk level of decision maker. The developed REITSP model was applied to the case study in Guangdong Province, China for its long-term electricity system planning. Crisp solutions under different aspiration risk levels for varying RPS targets were obtained and analyzed. The results showed that according to the current available renewable energy and affordable construction speed, the maximum RPS target for Guangzhou Province during 2016–2025 should be 17%. Higher RPS level would promote the renewable energy generation, especially solar power; meanwhile, it would reduce the CO2 emission and the imported electricity, but with greater investment cost. The obtained results and trade-off information would be valuable for the optimal long-term electricity system expansion planning when facing future uncertain situation.

Epidemiology of globus symptoms and associated psychological factors in China.

To investigate the lifetime prevalence, epidemiological characteristics and psychological factors of globus symptoms in Guangzhou (Guangzhou Province, China). A total of 3 360 individuals were randomly selected and participated in the study. Respondents completed questionnaires about their physical and psychological characteristics, globus symptomatology and the Glasgow-Edinburgh throat scale questionnaires and quality of sleep and life. Those who had experienced a globus sensation with no history of gastroesophageal reflux disease, dysphagia, odynophagia or alerting symptoms such as weight loss and hoarseness were diagnosed as having globus. A total of 3 006 respondents completed the questionnaires, giving a response rate of 89.5%. The overall lifetime prevalence of globus was 21.5%, with a peak age at disease onset of 35-54 years. The prevalence of globus was higher in participants from the urban region than those from the rural areas (26.5% vs 16.4%, P = 0.001). No sex-related difference was observed (P = 0.082). Anxiety (39.8% vs 22.3%, P = 0.001), depression (31.2% vs 18.0%, P = 0.001) and sleep disorders (23.7% vs 13.6%, P = 0.001) were significantly more common in respondents with globus than in those without. Scores on all dimensions of the 36-item short-form health survey, except physical function, were lower in respondents with globus than in those without (all P < 0.05). Globus symptoms are common and often accompanied by psychological and sleep disorders. The medical community should pay more attention to globus in clinical setting.

Relation of Age, Sex and Bone Mineral Density to Serum 25-Hydroxyvitamin D Levels in Chinese Women and Men.

To investigate the relation of circulating 25-hydroxyvitamin D (25[OH]D) levels to age, sex, and bone mineral density (BMD) in adults living in Guangzhou Province. This cross-sectional study comprised 188 women and 122 men aged 17-88 years who were randomly sampled among community-dwelling Guangzhou residents. BMD at the lumbar spine and femoral neck was measured by dual energy X-ray absorptiometry, and serum concentrations of 25(OH)D, parathyroid hormone (PTH), procollagen I N-terminal peptide, and beta C-telopeptide of collagen were assayed by electrochemiluminescence immunoassay. Serum 25(OH)D concentrations were divided into four subgroups: severe deficiency (<10 ng/mL), deficiency (10-20 ng/mL), insufficiency (20-30 ng/mL), and sufficiency (≥30 ng/mL). The mean age of participants was 47.39 ± 19.32 years. Serum 25(OH)D levels were significantly lower in women than men (25.35 ± 6.59 ng/mL vs 27.25 ± 7.94 ng/mL, P < 0.05). The prevalence of 25(OH)D severe deficiency (<10 ng/mL) was 1.6% in men, zero in women; 25(OH)D deficiency (10-20 ng/mL) was 22.9% in women and 20.5% in men; and 25(OH)D insufficiency (20-30 ng/mL) was 73.4% in women and 65.6% in men. An inverse relationship between serum 25(OH)D levels and age (r = -0.249, P < 0.01) was observed in men, but no correlation was found in women (r = 0.130, P > 0.05). Serum 25(OH)D levels were positively associated with lumbar spine and femoral neck BMD (r = 0.382, P < 0.01; r = 0.384, P < 0.01, respectively) in elderly women and (r = 0.332, P < 0.05; r = 0.260, P < 0.05, respectively) and in young men. When adjustments were made for age, correlations between serum 25(OH)D levels and lumbar spine and femoral neck BMD persisted (r = 0.325, P < 0.05; r = 0.323, P < 0.05, respectively) in elderly women. However, age-adjusted serum 25(OH)D levels were positively correlated with BMD at lumbar spine (r = 0.278, P < 0.05) but not at femoral neck (r = 0.165, P > 0.05) in young men. No association between unadjusted or age-adjusted serum 25(OH)D levels and lumbar spine and femoral neck BMD was found in young and middle-aged women and in middle-aged and elderly men. Neither serum PTH levels nor bone turnover markers were related to unadjusted and age-adjusted serum 25(OH)D levels in our participants. More than two-third of participants residing in Guangzhou had vitamin D insufficiency. Serum 25(OH)D level is an important biomarker for BMD in elderly women and young men.

Analysis of nucleotide sequences and genetic polymorphisms of UL138 gene of low passage human cytomegalovirus strains in Guangzhou

Objective To analyze the nucleotide sequences and genetic polymorphisms of UL138 gene of low passage human cytomegalovirus (HCMV) strains isolated from infants in Guangzhou province. Methods The low passage strains of HCMV were isolated from urine samples of 10 infants with HCMV infection in Guangzhou province and identified by multiplex PCR. The UL138 genes were amplified, cloned and identified with sequencing. The sequences were analyzed together with the homologous sequences of 10 clinical isolates published in GenBank. The sequences of UL138 genes were analyzed by using bioinformatics softwares for investigation of the post-translational modification sites, isoelectric points and second structures of UL138 proteins. Results Three low passage strains of HCMV (D2, D3 and D52) were isolated from infants with congenital HCMV infection. The complete sequences of UL138 genes of the three strains were submitted to GenBank after sequencing identification with the GenBank accession numbers of DQ180375, DQ180387 and DQ180359, respectively. The UL138 gene sequences of the three clinical isolates were highly conservative. Among the 841 base pairs of the UL138 gene sequences, mutations were identified in 16 sites with base substitution, no any insertion and deletion mutation was found. The 16 mutations resulted in 7 amino acid changes. No additional or deleted sites were found with regard to the post translational modification sites of UL138 protein in all clinical isolates except the Toledo strain. The isoelectric point of UL138 protein was 6.51 for all clinical isolates. Conclusion The UL138 genes and the deduced amino acid sequences of HCMV strains isolated from infants in Guangzhou were highly conservative, regardless of the polymorphism of UL138 gene. This study paved the way for further investigation on HCMV infection and its pathogenic mechanism. Key words: Human cytomegalovirus; Clinical isolate; UL138; Gene sequence; Polymorphism