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Yang Wang

Publications and source records attributed to Yang Wang.

At least 181 records · Page 10Linked to original sources
PubMed2004

[A review of basic statistics concepts,research design and statistical analysis methods].

Statistics is a methodology involving a great number of statistical methods. It results in confusion of many clinicians and researchers while they are meditating on how to analyze the collected data in their studies, selecting an appropriate statistical method from all. In fact, the statistical methods are closely correlated to the research design and the data types. Therefore only with a full comprehension of the design methods and the data types can we figure out a simple and practical means from diverse statistical analysis methods. Through the systematic illustration in this review, several statistical concepts, data types, design methods, and the proper way of explaining results with statistical tables and graphs will be demonstrated elaborately. It intends to help the clinicians and researchers select appropriate statistical methods and furthermore, interpret the statistical outcomes accurately in their research.

Humans↗
PubMed2004

[Collagen changes of allografting an acellular dermal matrix].

OBJECTIVE: To evaluate the collagen changes of allografting an acellular dermal matrix (allo-ADM). METHODS: The allo-ADM was grafted underneath the skin of SD rats. The content of collagen and the proportion of type I to III collagen was examined with a biochemical assay. RESULT: The content of collagen and the proportion of type I to III collagen in the allo-ADM group showed no significant changes. CONCLUSION: The allo-ADM could keep long time in the body and it may be an ideal material for soft tissue filling.

Animals↗
PubMed2004

[A review of statistical analysis methods in measurement data].

Measurement data, which is obtained by measuring the size of numeric value, is consisted of numerical variables. In clinic research, the collected data covers quite of numerical variables. Composed of those numerical variables, the measurement data has to be correspondingly analyzed in the special statistical methods in the light of their design methods. The statistical methods of measurement data include descriptive statistics and inferential statistics. Descriptive statistics is mainly used to describe the distribution laws and the characters/features of the data. For instance, when measuring the central tendency and dispersion tendency of the data, methods such as calculating the mean and the standard deviation can be considered. Inferential statistics is mainly employed to estimate the confidence limit such as estimating the 95% confidence interval and to have the hypothesis testing in the example of having t test and analysis of variance. By highlighting the specific statistical methods of measurement data, this review intends to help the clinicians and researchers select correct statistical methods in accordance with measurement data.

Data Interpretation, Statistical↗
PubMed2004

[Conservation tillage systems in North America and their significance for China].

Soil degradation through erosion and desertification reduces soil productivity, and is a serious problem in agricultural production of China. To avert our arable land from further degradation, soil management must be shifted from degrading tillage to conservation practices. Over viewing the technology used in the 20th century for controlling soil degradation from erosion, conservation tillage developed in the United States and adopted in South America and Africa is one of the most successful measures to overcome soil degradation problems. This paper reviewed the historical development and the current situation of conservation tillage systems used in North and South America, with special reference to their effects on soil erosion control and soil quality. The increasing adoption of conservation tillage systems in North and South America and Africa followed an enhanced awareness of the increasing risk of soil erosion and the high cost of fuel associated with conventional tillage. Many crucial points for successfully adopting conservation tillage systems were emphasized, such as equipment/tool development and chemical weed control. Adopting conservation tillage could provide China with low-priced means of reducing soil degradation and improving soil and water quality.

Agriculture↗
PubMed2004

[HUP98-HOXA9 transgenic mice are susceptible to N-ethyl-N-nitrosourea stimulation in leukemogenesis].

OBJECTIVE: In order to investigate the leukemogenic potential of NUP98-HOXA9 fusion gene in vivo. METHODS: Molecular cloning technology was used to construct NUP98-HOXA9 transgenic plasmid and NUP98-HOXA9 transgenic mice were generated. The genotype and phenotype of the NUP98-HOXA9 transgenic mice were analyzed by PCR, RT-PCR and colony-forming assay. The effect of N-ethyl-N-nitrosourea (ENU) stimulation on the transgenic mice was analyzed by peripheral blood count, bone marrow (BM) cells morphology pathological examination. RESULTS: The transgenic expression was detected in 5 independent lines of NUP98-HOXA9 transgenic mice, but no expected phenotypes was found in 2 year follow-up. Upon ENU stimulation, 2 of 10 transgenic mice developed myeloid leukemia, suggesting that NUP98-HOXA9 transgenic mice have increased susceptibility to ENU mutagenesis in leukemogenesis. CONCLUSION: The fusion gene expressed in BM cells of NUP98-HOXA9 transgenic mice. It seems that the expression of the fusion gene is insufficient to trigger leukemogenesis. However, the increased susceptibility to ENU mutagenesis suggests that NUP98-HOXA9 fusion gene might play a potential role in leukemogenesis.

Animals↗
PubMed2004

[Development of human myeloid leukemia-like phenotype in NUP98-PMX1 transgenic mice].

OBJECTIVE: In order to investigate the leukemogenic potential of NUP98-PMX1 fusion gene in vivo. METHODS: NUP98-PMX1 transgenic mice were generated, in which the fusion gene was driven by hCG promoter and expressed in myeloid cells at early stage of differentiation. Molecular cloning technology was used to construct NUP98-PMX1 transgenic plasmid. The genotype and phenotype of the NUP98-PMX1 transgenic mice were analyzed by PCR, RT-PCR, peripheral blood count (PBC), bone marrow (BM) cells morphology and pathological examination. RESULTS: NIH3T3 cells transfected with NUP98-PMX1 fusion gene grew faster, formed colonies in soft agar, and developed tumors in 10 inoculated nude mice. Among 8 disordered NUP98-PMX1 transgenic mice, 4 developed myeloid leukemia-like phenotype, including 3 resembling human chronic myeloid leukemia. CONCLUSION: NUP98-PMX1 has oncogenic activity and plays a crucial role in leukemogenesis.

Animals↗
PubMed2004

[Seasonal variations in biomass and salidroside content in roots of Rhodiola sachalinensis as affected by gauze and red film shading].

Rhodiola sachalinensis A. Bor, a perennial herb, belonging to the family Crassulaceae, is mainly distributed in mountains at the altitudes of 1,700-2,500 m. It is a typical alpine plant and a very important medicinal plant with high activities of anti-fatigue, anti-senescence, and anti-radiation, due to the secondary metabolite salidroside in its root. Our previous findings have proven that red light promotes salidroside synthesis remarkably but decreases biomass insignificantly, resulting in a higher yield of salidroside in roots of Rh. sachalinensis in a greenhouse. In order to investigate the influences of shading and red light on seasonal variations in biomass and salidroside content in Rh. sachalinensis roots, the effects on 3 or 4 years old Rh. sachalinensis plants in a nursery in Daxinganling Mountain (124 degrees 02' E, 50 degrees 30' N) were studied in 2001. Compared to the control (CK) of full sunlight, 6 treatments with neutral transparent film and gauze, or red film alone had been conducted for 131 days. In treatment I, Rh. sachalinensis was shaded with neutral transparent film and gauze to achieve an irradiance 51.8% of full sunlight. In treatment II, the plants were shaded by red film alone, but the irradiance was as that in treatment I. In treatments III, IV, V and VI, neutral transparent film and gauze were originally used on May 8, then shifted to red film on Jun 3, July 4, August 4 and September 2, respectively and all experiments stopped on September 16, 2001. Rh. sachalinensis roots were harvested on 2-4th from June to September and finally on September 16, and root-biomass and salidroside content were measured. Root-biomass in plants decreased significantly under shading with neutral transparent film and gauze compared to the control with full sunlight, but little variations in salidroside content and yield. In comparison with shading by neutral transparent film and gauze, root-biomass reduced lightly and salidroside content and yield in roots were increased remarkably under red-film shading. At the end of the season, salidroside content under red light was 163% in 3-year-old and 155% in 4-year-old Rh. sachalinensis roots; whereas salidroside yields were 144% in 3-year-old and 145% in 4-year-old Rh. sachalinensis roots to those in plants under shading. The results also showed that the enhancement in the salidroside content and yield were little related to the duration of red film shading, which implied that in order to increase salidroside content and get higher salidroside yield, but less affect root-biomass, Rh. sachalinensis may be shaded with red film just several days before harvest.

Biomass↗
PubMed2004

[Ultrasound-guided percutaneous microwave coagulation therapy for hepatic metastases].

OBJECTIVE: To analyze the therapeutic results and prognostic factors of hepatic metastases treated by ultrasound-guided percutaneous microwave coagulation. METHODS: Seventy-four patients with 149 nodules of hepatic metastases were given percutaneous microwave coagulation therapy. The longest diameter of the metastatic nodule ranged from 0.7 - 6.8 cm (mean, 3.1 +/- 1.8 cm). The cumulative survival rate was analyzed by Kaplan-Meier method and the difference between groups was compared with log-rank test. Cox proportional hazard model was used to determine potential prognostic variables. RESULTS: The follow-up period for the 74 patients was 5 - 83 months (mean, 25.1 +/- 11.4 months). The overall 1-, 3-, and 5-year cumulative survival rates were 91.4%, 46.4% and 29.0%, respectively. The log-rank test showed that number of metastases, tumor size, tumor cell differentiation and local recurrence or new metastases were statistically significant prognostic factors; while age, sex and site of primary tumors were not significant prognostic factors. Multivariate analysis revealed that tumor differentiation, number of metastases and recurrence or new metastases were statistically significant prognostic factors. CONCLUSION: Ultrasound-guided percutaneous microwave coagulation therapy for hepatic metastases in patients with single metastasis, well-differentiated tumor, and without recurrence and new metastases could achieve long-term survival.

Adult↗
PubMed2004

[The effect of minerals on transformation of sulfur during pyrolysis and partial gasification].

In this study, the effect of acid treatment of Yima coal on predesulfurization during pyrolysis and partial gasification were investigated. The coal was treated with HCl, HCl-HF and HCl-HNO3 solution, in which different minerals were eliminated. The whole process could be divided into pyrolysis and partial gasification. In pyrolysis process, the evolution of H2S and COS show two peaks, which were 450 degrees C and 600 degrees C respectively. At high temperature, the amount of H2S evolution from acid treated coal was markedly increased compared to the raw coal through the elimination of minerals. In the case of HCl-HNO3 treated sample, the H2S evolution in the low temperature region, below 500 degrees C, was reduced and the COS evolution in higher temperature region, above 500 degrees C, was increased by the chemical oxidation. In the partial gasification process, the sulfide sulfur removal of acid treated coal char was increased, reached about 100% at 800 degrees C. The maximum of total and sulfide sulfur removal of parent coal char were 46.39% and 52.97% at 700 degrees C. Compared to acid treated coal char, the effect of alkaline minerals for fixing sulfur was strengthened with increasing the temperature. The organic sulfur of acid treated coal char was released with carbon gasification, and the value could be constant.

Air Pollutants↗
PubMed2004

[A review of correlation, regression and multiple factors analysis methods.].

In clinical research, the relationships between two factors or among multiple factors are frequently explored. Dependence and covariation are two kinds of relationships between two factors. Regression and correlation analysis are the appropriate methods in measuring and evaluating those factors. Multiple analysis methods are widely used in the studies of risk factors among diseases, data analyses of diagnostic tests, effects evaluation of a prevention and treatment, analyses of prognosis, etc. Multiple analysis methods could interpret the influences of each factor more specifically than single factor analysis, and provide more possibilities to improve the quality of a research. In this review, the fundamental principle and utilities on clinical research of several statistical methods are introduced in this paper, such as linear correlation, linear regression, rank regression, rank correlation, multiple linear regression and logistic regression. It intends to help the clinicians and researchers to select the appropriate statistical methods to collect and analyze the data.

Epidemiologic Studies↗
PubMed2004

[A review of nonparametric test].

For some data which have skewness distribution or unknown distribution, it is impossible to apply parametric test. Nonparametric test will be a good choice for this kind of data in testing the distribution of the population. The nonparametric test is widely used in clinical research by its goodness of stability and adaptiveness. However, the effectiveness is cutting down by losing some essential information. So, parametric test will be recommended when the data meet the requirements. This paper introduces the basic concepts and methods of nonparametric test for the physicians to understand this important tool.

Humans↗
PubMed2004

Lanthanum inhibited the binding of LPS with monocyte and CD 14 expression upregulation.

To investigate the effects of lanthanum chloride on binding of LPS to monocyte and CD 14 expression upregulation induced by LPS, human monocytes were analyzed by flow cytometry (FCM). The results indicated that lanthanum chloride could decrease the binding rate of LPS with monocyte significantly. LPS upregulated the expression of CD 14 on monocyte in a dose dependant manner, however, lanthanum chloride could inhibit the increase of CD 14 expression on monocytes by halves.

Flow Cytometry↗
PubMed2003

Charge distributions in metallic alloys: a charge-excess functional theory approach.

The distribution of local charge (DLC) excesses in metallic alloys, previously obtained as a result of the analysis of order N electronic structure calculations, is derived from a variational principle. A phenomenological charge-excess functional theory is obtained which is determined by three concentration dependent, material specific parameters that can be obtained from ab initio calculations. The theory requires modest computational efforts and reproduces with an excellent accuracy the DLC and the electrostatic energies of ordered, substitutionally disordered, or segregating metallic alloys and, hence, can be considered an efficient approach alternative to conventional electronic structure calculations. The substantial reduction of computing time opens new perspectives for the understanding of metallic systems and their mechanical properties.

Journal Article↗
PubMed2003

Lymphotoxin pathway directs thymic Aire expression.

The autoimmune regulator Aire is a key mediator of central tolerance for peripherally restricted antigens. Its absence in human patients results in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. The cellular signals that regulate Aire expression are undefined. We show here that lymphotoxin signaling is necessary for the expression of Aire and its downstream target genes. The failure of Aire induction in the thymi of lymphotoxin-deficient and lymphotoxin-beta receptor-deficient mice contributes to overt autoimmunity against self antigens normally protected by Aire. Conversely, stimulation of lymphotoxin-beta receptor by agonistic antibody leads to increased expression of Aire and tissue-restricted antigens in both intact thymi and cultured thymic epithelial cell line. These findings define the essential cross-talk between thymocytes and thymic stroma that is required for central tolerance.

Animals↗
PubMed2003

Manduca sexta serpin-3 regulates prophenoloxidase activation in response to infection by inhibiting prophenoloxidase-activating proteinases.

Many serine proteinase inhibitors of the serpin superfamily have evolved in vertebrates and invertebrates to regulate serine proteinase cascades that mediate the host defense responses. We have isolated an immune-responsive serpin from the tobacco hornworm, Manduca sexta. This inhibitor, M. sexta serpin-3, contains a reactive site loop strikingly similar to the proteolytic activation site in prophenoloxidase (pro-PO). Molecular cloning and sequence comparison indicate that serpin-3 is orthologous to Drosophila melanogaster serpin 27A, a regulator of melanization. M. sexta serpin-3 is constitutively present in hemolymph at a low concentration of 5-12 microg/ml and increases to 30-75 microg/ml after a microbial challenge. Recombinant serpin-3 efficiently blocks pro-PO activation in the hemolymph, and it forms SDS-stable acyl-enzyme complexes with purified pro-PO-activating proteinases (PAPs) from M. sexta. PAP-serpin-3 complexes were isolated by immunoaffinity chromatography from hemolymph activated by treatment with Micrococcus luteus. Kinetic analysis of PAP-serpin-3 association strongly suggests that serpin-3 is a physiological regulator of the pro-PO activation reaction.

Animals↗
PubMed2003

Predicting demographic group structures based on DNA sequence data.

The ability to infer relationships between groups of sequences, either by searching for their evolutionary history or by comparing their sequence similarity, can be a crucial step in hypothesis testing. Interpreting relationships of human immunodeficiency virus type 1 (HIV-1) sequences can be challenging because of their rapidly evolving genomes, but it may also lead to a better understanding of the underlying biology. Several studies have focused on the evolution of HIV-1, but there is little information to link sequence similarities and evolutionary histories of HIV-1 to the epidemiological information of the infected individual. Our goal was to correlate patterns of HIV-1 genetic diversity with epidemiological information, including risk and demographic factors. These correlations were then used to predict epidemiological information through analyzing short stretches of HIV-1 sequence. Using standard phylogenetic and phenetic techniques on 100 HIV-1 subtype B sequences, we were able to show some correlation between the viral sequences and the geographic area of infection and the risk of men who engage in sex with men. To help identify more subtle relationships between the viral sequences, the method of multidimensional scaling (MDS) was performed. That method identified statistically significant correlations between the viral sequences and the risk factors of men who engage in sex with men and individuals who engage in sex with injection drug users or use injection drugs themselves. Using tree construction, MDS, and newly developed likelihood assignment methods on the original 100 samples we sequenced, and also on a set of blinded samples, we were able to predict demographic/risk group membership at a rate statistically better than by chance alone. Such methods may make it possible to identify viral variants belonging to specific demographic groups by examining only a small portion of the HIV-1 genome. Such predictions of demographic epidemiology based on sequence information may become valuable in assigning different treatment regimens to infected individuals.

Adolescent↗
PubMed2003

Neuroprotective effects of bone marrow stromal cells on rat organotypic hippocampal slice culture model of cerebral ischemia.

Organotypic hippocampal slice cultures prepared from newborn rats were maintained in vitro for 9 days. Cultures were then exposed to 30 min of combined oxygen-glucose deprivation (OGD). After OGD, the area covered by neurites was decreased. The dead cells of hippocampal slices in the ischemia group were 40.4% at day 3 and 41.6% at day 7 after OGD. The ultrastructure of the CA1 region of the slices was seriously damaged. While hippocampal slices were cultured in combination with bone marrow stromal cells (MSCs), the average area covered by neurites was comparatively increased. The dead cells were only 25.2% at day 3 and 27.1% at day 7 after coculture. The damage of the ultrastructure of the CA1 region in the coculture group was reduced significantly. Thus, in an in vitro model of simulated ischemia, MSCs can promote the outgrowth of neurites from hippocampal slices and alleviate cell damage. The neuroprotective effect might be mediated through diffusible neurotrophic factors secreted from MSCs.

Animals↗