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Biomedical subjects

X J Wang

Publications and source records attributed to X J Wang.

At least 19 recordsLinked to original sources
PubMed2006

Source apportionment of polycyclic aromatic hydrocarbons in surface soil in Tianjin, China.

Principal component analysis and multiple linear regression were applied to apportion sources of polycyclic aromatic hydrocarbons (PAHs) in surface soils of Tianjin, China based on the measured PAH concentrations of 188 surface soil samples. Four principal components were identified representing coal combustion, petroleum, coke oven plus biomass burning, and chemical industry discharge, respectively. The contributions of major sources were quantified as 41% from coal, 20% from petroleum, and 39% from coking and biomass, which are compatible with PAH emissions estimated based on fuel consumption and emission factors. When the study area was divided into three zones with distinctive differences in soil PAH concentration and profile, different source features were unveiled. For the industrialized Tanggu-Hangu zone, the major contributors were cooking (43%), coal (37%) and vehicle exhaust (20%). In rural area, however, in addition to the three main sources, biomass burning was also important (13%). In urban-suburban zone, incineration accounted for one fourth of the total.

Biomass↗
PubMed2006

Air quality improvement estimation and assessment using contingent valuation method, a case study in Beijing.

The aim of the paper is to estimate and assess residents' willingness to pay to improve air quality in the urban area of Beijing using the Contingent Valuation Method (CVM). The mean willingness to pay (WTP) for a 50% reduction of harmful substances in the air was 143 CNY per household per year, and the total WTP of the residents in the study area was 336 million CNY per year. As a proportion of household annual income, the mean WTP amounted to 0.7%. Four socio-economic variables were found to have significant impacts on residents' willingness to pay. The analysis results illustrated that WTP increases with income and education level, and decreases with household population and age. The willingness was larger for residents in the urban districts than those in the suburban districts. It was found that most of the protest bids lay on interviewees' incomplete perception of the values of environmental amenity. The influence of household income on people's willingness to pay illustrated in this study reflects a causal force of Beijing's transition to market economy that households created to have disposable income are more likely to care about environmental quality. The results of this study strike an optimistic note on the possibility of measuring the total economic value of environmental quality improvement by using the CVM in China. Suggestions on implication of the CVM for both academics and policy makers are provided in the paper.

Air↗
PubMed2006

Demodulation algorithm for spatial-frequency-division-multiplexed fiber-optic Fizeau strain sensor networks.

A demodulation algorithm for spatial-frequency-division-multiplexed fiber-optic Fizeau strain sensor networks with a large number of sensors is proposed to effectively reduce the cross talk between any two adjacent sensors and hence substantially enhance the multiplexing capability of the network, which is based on the Pisarenko algorithm. The cross talk between two fiber-optic Fizeau sensors is investigated experimentally. The experimental results show that a strain accuracy of better than +/-10 micro permittivity can be achieved even when the cavity length difference is approximately 100 microm. It was demonstrated that the multiplexing capability of the spatial-frequency-division-multiplexed fiber-optic Fizeau sensor network can be approximately 5 times greater than that of the conventional fast-Fourier-transform algorithm, and this can lead to achievement of a sensing network with a multiplexing capability of as many as 1000 Fizeau sensors.

Journal Article↗
PubMed2006

Radical treatment of axillary osmidrosis by subdermal excision of apocrine glands: a prospective study in 31 cases.

Axillary osmidrosis is a troublesome and distressing problem. Medical treatment is only temporally effective. From March 2003 to November 2004, 36 patients with axillary osmidrosis (nine cases combined with axillary hyperhidrosis) have been treated by excision of the subcutaneous glands via a small transverse incision, of which 31 cases could be followed up for a minimum of 3 months (average 7.3 months). In terms of malodour elimination, 30 cases had good results, one had fair result, and none had a poor result. All patients reported significant reducing of sweating, especially those with hyperhidrosis. Postoperative complications were minor, including small haematoma (one axillae), small seroma (two axillae), and superficial epidermal necrosis (21 axillae) which were all spontaneously healed within a week. Twenty-nine (93.5%) patients were very satisfied with the procedure and two (6.5%) patients satisfied, with none regretful. The operation has the advantage of a high success rate in radical elimination of the malodour with minor complications.

Adolescent↗
PubMed2006

Severe cicatrical ectropion: repair with a large advancement flap and autologous fascia sling.

We present a 35-year-old male who, 9 years ago, had his right orbit and face injured in a gun blast accident resulting in severe cicatrical ectropion of the right lower lid. A large advancement facial flap with incision at the naso-labial fold was designed to repair the skin defect, and a strip of autologous fascia lata was grafted in the lower lid to serve as a static sling. The facial flap was dissected and elevated at the subcutaneous fat layer. With adequate separation of the flap and suspension sutures at the undersurface of the flap, tension free closure of the wound was obtained and the ectropion completely corrected. The postoperative course was uneventful and the patient very satisfied with the results.

Adult↗
PubMed2006

Single-nucleotide polymorphism identification in the caprine myostatin gene.

Polymerase chain reaction (PCR) products of MSTN gene amplified from 35 goats representing 17 Chinese indigenous goat breeds and five imported goat breeds were sequenced to identify the single-nucleotide polymorphisms (SNPs) of a 379-bp fragment including part of intron 2 and exon 3 of MSTN gene. A total of eight SNPs (A1980G, G1981C, A1982G, G1984T, A2121G, T2124C, G2174A and A2246G) were identified among the sequenced goats. The SNPs found are all located in intron 2 except for A2246G, which was a synonymous mutation in exon 3. Four haplotypes were sorted from these eight SNPs, of which, haplotype I (AGAGATGA) and haplotype II (GCGTGTAA) are the two main haplotypes with the frequency of 77.8% and 14.8% respectively. The SNPs found at positions 1980, 1981, 1982, 1984 and 2121 might be linked to inheritance completely.

Animals↗
PubMed2006

Bone marrow cells can give rise to ameloblast-like cells.

Post-eruptive loss of ameloblasts requires identification of alternative sources for these cells to realize tooth-tissue-engineering strategies. Recent reports showed that bone-marrow-derived cells can give rise to different types of epithelial cells, suggesting their potential to serve as a source for ameloblasts. To investigate this potential, we mixed c-Kit(+)-enriched bone marrow cells with embryonic dental epithelial cells and cultured them in re-association with dental mesenchyme. Non-dividing, polarized, and secretory ameloblast-like cells were achieved without cell fusion. Before basement membrane reconstitution, some bone marrow cells migrated to the mesenchyme, where they exhibited morphological, molecular, and functional characteristics of odontoblasts. These results show, for the first time, that bone-marrow-derived cells can be reprogrammed to give rise to ameloblast-like cells, offering novel possibilities for tooth-tissue engineering and the study of the simultaneous differentiation of one bone marrow cell subpopulation into cells of two different embryonic lineages.

Ameloblasts↗
PubMed2005

Geostatistical analysis and kriging of Hexachlorocyclohexane residues in topsoil from Tianjin, China.

A previously published data set of HCH isomer concentrations in topsoil samples from Tianjin, China, was subjected to geospatial analysis. Semivariograms were calculated and modeled using geostatistical techniques. Parameters of semivariogram models were analyzed and compared for four HCH isomers. Two-dimensional ordinary block kriging was applied to HCH isomers data set for mapping purposes. Dot maps and gray-scaled raster maps of HCH concentrations were presented based on kriging results. The appropriateness of the kriging procedure for mapping purposes was evaluated based on the kriging errors and kriging variances. It was found that ordinary block kriging can be applied to interpolate HCH concentrations in Tianjin topsoil with acceptable accuracy for mapping purposes.

China↗
PubMed2005

Modeling the dynamic changes in concentrations of gamma-hexachlorocyclohexane (gamma-HCH) in Tianjin region from 1953 to 2020.

A level IV fugacity model was used to simulate the dynamic changes of gamma-hexachlorocyclohexane (gamma-HCH) concentrations in environmental media in Tianjin, China. A similar model (level III) was previously used and validated under steady state conditions; this paper explores its dynamic behavior. Application of the level IV fugacity model has been validated using independently observed gamma-HCH concentrations in various media during the early 1980s and during 2001. Sensitivity analysis was conducted using coefficient-of-variation normalized sensitivity coefficients. The model was also subject to uncertainty analysis using Monte Carlo simulation. It was found that concentrations of gamma-HCH reached within 95% of their steady-state levels in all media after less than 15 years. Around one order-of-magnitude decreases in gamma-HCH concentrations in various media occurred between 1993 and 2001. We project that gamma-HCH concentrations will decrease another 1.7-1.9 orders of magnitude to reach 1.1 (0.9-1.2) x 10(-14), 2.7 (2.5-3.0) x 10(-10), 1.2 (1.1-1.3) x 10(-7), and 6.1 (5.4-6.8) x 10(-8) mol/m(3), in air, water, soil, and sediment, respectively, by 2020. The sensitivities and true uncertainty of the model are discussed.

Air Pollutants↗
PubMed2005

Organochlorine pesticides in agricultural soil and vegetables from Tianjin, China.

Samples of eight types of vegetables, the rhizosphere soils, and bulk soils were collected from two sites (A and B) in Tianjin, China for the determination of hexachlorocyclohexane isomers (HCHs) and dichlorodiphenyltrichloroethane and metabolites (DDXs). The average concentrations of total HCHs and DDXs in the bulk soils were 3.6 and 80.1 ng/g for site A and 102 and 235 ng/g for site B, respectively. Relative accumulations of HCHs and DDXs in the rhizosphere soil from site A but not site B were demonstrated. The concentrations of total HCHs and DDXs in vegetable roots were 3.6-60 and 4.2-73 ng/g for site A and 15-152 and 7.1-136 ng/g for site B, respectively. Difference in bioaccumulation among various vegetables, especially between tuber and fibrous vegetables was significant. DDXs in spinach and cauliflower from site B and lindane (gamma-HCH) in cauliflower from both sites and violet from site B exceeded the maximum residual limits. Linear correlation of log-transformed HCHs and DDXs contents between the vegetable roots and the rhizosphere soils suggests the direct uptake of HCHs and DDXs.

Agriculture↗
PubMed2005

Spatial analysis and eutrophication assessment for chlorophyll a in Taihu Lake.

Spatial structure analysis and kriging analysis have been identified to be useful tools in illustrating the spatial patterns of variables. Taihu Lake is one of the largest fresh water lakes in China, and has suffered serious eutrophication in recent years due to the rapid economic development and growing environmental pollution in the Taihu Catchment. In this paper, spatial structural analysis, kriging interpolation and eutrophication assessment were carried out for chlorophyll a in the lake. Studies show that spherical model could be applied to fit all experimental variograms. Positive nuggets were observed for three directions except NE-SW direction. The variograms show some anisotropy with anisotropic ratio falling within 1.76. The spatial structural patterns of chlorophyll a in the lake were affected by factors such as distribution of pollution sources, water flow and wind. Two-dimensional ordinary block kriging was applied for interpolation process. An eutrophication assessment map was also made based on a water-quality evaluation standard. Results show that the content of chlorophyll a in Taihu Lake was quite high. The whole lake has suffered serious eutrophication. However, the eutrophic situation varied in space. Higher contents of chlorophyll a appeared mainly in the northern part of the lake.

China↗
PubMed2005

Contamination of rivers in Tianjin, China by polycyclic aromatic hydrocarbons.

Tianjin urban/industrial complex is highly polluted by some persistent organic pollutants. In this study, the levels of 16 priority polycyclic aromatic hydrocarbons (PAHs) were tested in sediment, water, and suspended particulate matter (SPM) samples in 10 rivers in Tianjin. The total concentration of 16 PAHs varied from 0.787 to 1943 microg/g dry weight in sediment, from 45.81 to 1272 ng/L in water, and from 0.938 to 64.2 microg/g dry weight in SPM. The levels of PAHs in these media are high in comparison with values reported from other river and marine systems. Variability of total concentrations of PAHs in sediment, water, and SPM from nine different rivers is consistent with each other. No obvious trends of total PAHs concentration variations were found between upstream and downstream sediment, water, and SPM samples for most rivers, which indicate local inputs and disturbances along these rivers. The spatial distributions of three-phase PAHs are very similar to each other, and they are also similar to those found in topsoil. However, their chemical profiles are significantly different from that of topsoil. The change of profiles is consistent with the different aqueous transport capability of 16 PAHs. Low molecular weight PAHs predomination suggests a relatively recent local source and coal combustion source of PAHs in the study area.

China↗
PubMed2005

A point mutation of the ED1 gene in a Japanese family with X-linked hypohidrotic ectodermal dysplasia.

X-linked hypohidrotic ectodermal dysplasia (EDA) is characterized by the hypoplasia or absence of hair, teeth and sweat glands. In this study, the authors investigated the ED1 gene in a Japanese family with X-linked hypohidrotic ectodermal dysplasia. The only affected male fulfils the diagnostic criteria for this disorder. His parents were not consanguineous and both of them were healthy. After informed consent, genomic DNA was isolated from the peripheral blood lymphocytes or oral buccal epithelial cells of all members of the family. A polymerase chain reaction fragment containing exon 9 of the ED1 gene was amplified using primers. The patient's amplified fragment, as well as those from his father, mother and sister, were directly sequenced. The sequence from the patient revealed a point mutation (G1149A) in exon 8 of the ED1 gene, which changes codon 291 from glycine to arginine. Heterozygosity was demonstrated in his mother and sister. This mutation has not been reported previously. The amino acid substitution is predicted to disrupt the transmembrane domain, which strongly implies that this is the disease-causing mutation in the family.

Amino Acid Substitution↗
PubMed2004

Use of sequential ASE extraction to evaluate the bioavailability of DDT and its metabolites to wheat roots in soils with various organic carbon contents.

An accelerated solvent extraction (ASE) procedure using water, n-hexane and a mixture of n-hexane and acetone as solvents in sequence was developed and tested to evaluate the bioavailability of DDT and its metabolites including p,p'-DDT, o,p'-DDT, p,p'-DDE, and p,p'-DDD (SigmaDDTs) to wheat uptake from soils characterized by varied organic carbon contents. Results indicated that the extractability of SigmaDDTs with water was enhanced considerably in the presence of water soluble organic carbon (WSOC), while the amount of SigmaDDTs extracted with n-hexane was negatively correlated to the content of water insoluble organic carbon (WIOC). The interaction between SigmaDDTs and WIOC also reduced the bioavailability of the pesticides to wheat roots during uptake. There was a good positive correlation between the amount of SigmaDDTs extracted by n-hexane and the amount of SigmaDDTs accumulated in wheat roots, suggesting some potential for the use of the n-hexane ASE-extracted fraction as an indicator of SigmaDDTs' bioavailability to plant uptake. As such, the three sequentially extracted fractions may be viewed as representing the mobile, bioavailable, and fixed pools of SigmaDDTs in the soil.

Biological Availability↗
PubMed2004

Polycyclic aromatic hydrocarbons (PAHs) in agricultural soil and vegetables from Tianjin.

Several types of vegetables were collected from two contaminated sites in Tianjin, China. The bulk soil and the rhizosphere soil samples were also collected from the same plots. Sixteen PAHs in the samples were measured. The total concentrations of PAH16 in the bulk soil from the two sites were 1.08 and 6.25 microg/g, respectively, with similar pattern. The concentrations of PAH16 and individual compounds in the rhizosphere were significantly higher than those in the bulk soil with mean values of 2.25 and 7.82 microg/g for the two sites, respectively. The contents of both total and dissolved organic matter in the rhizosphere were also higher than those in the bulk soil. Almost all PAH compounds studied were detected in both roots and aerial parts of the vegetables studied. Abundance of higher molecular weight PAHs in vegetable, however, was lower than that in soil. Concentrations of PAH16 in vegetable were higher than those reported in the literature for other areas. It appears that agricultural soils and vegetables in Tianjin, especially those from the site located immediately next to an urban district and irrigated with wastewater for several decades, are severely contaminated by PAHs. Among the eight types of vegetable studied, the highest concentration of PAHs was found in cauliflower. By average, the concentration of PAH16 in the aerial part of vegetables was 6.5 times higher as that in vegetable root, suggesting that foliar uptake is the primary transfer pathway of PAHs from environment to vegetables.

China↗
PubMed2004

Level and distribution of DDT in surface soils from Tianjin, China.

One hundred and eighty eight surface soil samples were collected from the Tianjin area to study the contamination of DDT and its metabolites. Measurements were taken for p,p'-DDE, p,p'-DDD, p,p'-DDT, o,p'-DDE, o,p'-DDD and o,p'-DDT for all samples. The results indicated that p,p'-DDT and p,p'-DDE were the predominant contaminant compounds in the surface soil samples, with mean concentrations of 27.5 and 18.8 ng g(-1) respectively. No significant differences in DDT concentrations were found between the soils from wastewater treated irrigated areas and other areas, suggesting that wastewater irrigation is not an important source of DDT in the area. However, the spatial distribution of soil DDTs levels in the area did correlate well with early direct application rates of pesticides. In addition, both pH level and organic carbon content are also known factors affecting the level of DDT and its metabolites. Although it was assumed that the use of these chemicals was banned in the early 1980s, the current concentration levels appear to be too high to be mere residuals after 20 years degradation.

Agriculture↗