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X L Yin

Publications and source records attributed to X L Yin.

8 recordsLinked to original sources
PubMed2007

Transport of Sr2+ and SrEDTA2- in partially-saturated and heterogeneous sediments.

Strontium-90 has migrated deep into the unsaturated subsurface beneath leaking storage tanks in the Waste Management Areas (WMA) at the U.S. Department of Energy's (DOE) Hanford Reservation. Faster than expected transport of contaminants in the vadose zone is typically attributed to either physical hydrologic processes such as development of preferential flow pathways, or to geochemical processes such as the formation of stable, anionic complexes with organic chelates, e.g., ethylenediaminetetraacetic acid (EDTA). The goal of this paper is to determine whether hydrological processes in the Hanford sediments can influence the geochemistry of the system and hence control transport of Sr(2+) and SrEDTA(2-). The study used batch isotherms, saturated packed column experiments, and an unsaturated transport experiment in an undisturbed core. Isotherms and repacked column experiments suggested that the SrEDTA(2-) complex was unstable in the presence of Hanford sediments, resulting in dissociation and transport of Sr(2+) as a divalent cation. A decrease in sorption with increasing solid:solution ratio for Sr(2+) and SrEDTA(2-) suggested mineral dissolution resulted in competition for sorption sites and the formation of stable aqueous complexes. This was confirmed by detection of MgEDTA(2-), MnEDTA(2-), PbEDTA(2-), and unidentified Sr and Ca complexes. Displacement of Sr(2+) through a partially-saturated undisturbed core resulted in less retardation and more irreversible sorption than was observed in the saturated repacked columns, and model results suggested a significant reservoir (49%) of immobile water was present during transport through the heterogeneous layered sediments. The undisturbed core was subsequently disassembled along distinct bedding planes and subjected to sequential extractions. Strontium was unequally distributed between carbonates (49%), ion exchange sites (37%), and the oxide (14%) fraction. An inverse relationship between mass wetness and Sr suggested that sandy sediments of low water content constituted the immobile flow regime. Our results suggested that the sequestration of Sr(2+) in partially-saturated, heterogeneous sediments was most likely due to the formation of immobile water in drier regions having low hydraulic conductivities.

Edetic Acid↗
PubMed2002

An economic analysis of biomass gasification and power generation in China.

With vast territory and abundant biomass resources China appears to have suitable conditions to develop biomass utilization technologies. As an important decentralized power technology, biomass gasification and power generation (BGPG) has a potential market in making use of biomass wastes. In spite of the relatively high cost for controlling secondary pollution by wastewater, BGPG is economically feasible and can give a financial return owing to the low price of biomass wastes and insufficient power supply at present in some regions of China. In this work, experimental data from 1 MW-scale circulating fluidized bed (CFB) BGPG plants constructed recently in China were analyzed; and it was found that the unit capital cost of BGPG is only 60-70% of coal power station and its operation cost is much lower than that of conventional power plants. However, due to the relatively low efficiency of small-scale plant, the current BGPG technology will lose its economic attraction when its capacity is smaller than 160 kW or the price of biomass is higher than 200 Yuan RMB/ton. The development of medium-scale BGPG plants, with capacity ranging from 1000 to 5000 kW, is recommended; as is the demonstration of BGPG technology in suitable enterprises (e.g. rice mill and timber mill) in developing countries where large amounts of biomass wastes are available so that biomass collection and transportation can be avoided and the operation cost can be lowered.

Biodegradation, Environmental↗
PubMed2001

Detection of multiple gene amplifications in glioblastoma multiforme using array-based comparative genomic hybridization.

We have used a new method of genomic microarray to investigate amplification of oncogenes throughout the genome of glioblastoma multiforme (GBM). Array-based comparative genomic hybridization (array CGH) allows for simultaneous examination of 58 oncogenes/amplicons that are commonly amplified in various human cancers. Amplification of multiple oncogenes in human cancers can be rapidly determined in a single experiment. Tumor DNA and normal control DNA were labeled by nick translation with green- and red-tagged nucleotides, respectively. Instead of hybridizing to normal metaphase chromosomes in conventional comparative genomic hybridization (CGH), the probes of the mixed fluorescent labeled DNA were applied to genomic array templates comprised of P1, PAC, and BAC clones of 58 target oncogenes. The baseline for measuring deviations was established by performing a series of independent array CGH using test and reference DNA made from normal individuals. In the present study, we examined fourteen GBMs (seven cell lines and seven tumours) with CGH and array CGH to reveal the particular oncogenes associated with this cancer. High-level amplifications were identified on the oncogenes/amplicons CDK4, GLI, MYCN, MYC, MDM2, and PDGFRA. The highest frequencies of gains were detected on PIK3CA (64.3%), EGFR (57.1%), CSE1L (57.1%), NRAS (50%), MYCN (42.9%), FGR (35.7%), ESR (35.7%), PGY1 (35.7%), and D17S167 (35.7%). These genes are suggested to be involved in the GBM tumorigenesis.

Brain Neoplasms↗
PubMed2001

Analysis of loss of heterozygosity on chromosomes 10q, 11, and 16 in medulloblastomas.

OBJECT: The loss of genetic material from specific chromosome loci is a common feature in the oncogenesis of tumors and is often indicative of the presence of important tumor suppressor genes at these loci. Recent molecular genetic analyses have demonstrated frequent loss of chromosomes 10q, 11, and 16 in medulloblastomas. The aim of this study was to localize the targeted deletion regions on the three aforementioned chromosomes in medulloblastomas. METHODS: Loss of heterozygosity (LOH) was examined on chromosomes 10q, 11, and 16 in a series of 22 primary and two recurrent medulloblastomas by using polymerase chain reaction-based microsatellite analysis. The DNA extracted from the tumors and corresponding normal blood samples were amplified independently in the presence of radioactively labeled microsatellite primers, resolved by denaturing gel electrophoresis and processed for autoradiography. The DNA obtained from control blood samples that displayed allelic heterozygosity at a given microsatellite locus were considered informative. Loss of heterozygosity was inferred when the allelic signal intensity of the tumor sample was reduced by at least 40%, relative to that of the constitutional control. The LOH analysis demonstrated that deletions of chromosomes 10q, 11p, and 16q are recurrent genetic events in the development of medulloblastomas. Three subchromosomal regions of loss have been identified and are localized to the deleted in malignant brain tumors 1 [DMBT1] gene site on chromosomes 10q25, 11p13-11p15.1, and 16q24.1-24.3. CONCLUSIONS: These results indicate that DMBT1 is closely associated with the oncogenesis of medulloblastomas and highlight regions of loss on chromosomes 11p and 16q for further fine mapping and cloning of candidate tumor suppressor genes that are important for the genesis of medulloblastoma.

Adolescent↗
PubMed2000

Detection of chromosomal imbalances in central neurocytomas by using comparative genomic hybridization.

OBJECT: Central neurocytomas are rare neuronal tumors commonly found in the intraventricular regions. Little is known about the tumorigenesis of these neoplasms. The aim of this study was to provide an overview of genetic imbalances in central neurocytomas. METHODS: In this study, comparative genomic hybridization was used to identify DNA sequence copy number changes (losses and gains) in a series of 10 central neurocytomas. Tumor DNA and normal reference DNA were differentially labeled and allowed to cohybridize to normal metaphase chromosomes. After hybridization and fluorescent staining of the bound DNA, regions of gain or of loss of DNA sequences were detected as changes in the tumor/normal fluorescence intensity ratio along the target metaphase chromosomes. A gain of DNA sequence was detected in chromosomes 2p, 10q, and 18q. A protooncogene, Bcl2, which maps to 18q21, was evaluated by immunohistochemical analysis to determine its role in the formation of central neurocytomas. CONCLUSIONS: In this study the authors identified recurrent genetic changes on chromosomes 2p, 10q, and 18q in central neurocytomas and highlighted chromosomal regions for additional mapping and cloning of candidate genes that are important in the development of central neurocytomas.

Adolescent↗
PubMed2000

[Role of pp60c-src in mitogen-activated protein kinase activation of vascular smooth muscle cells].

The effect of pp60c-src on mitogen-activated protein kinase (MAPK) activation induced by angiotensin II (Ang II) in vascular smooth muscle cells (VSMCs) was observed to explore the signal transduction process of VSMCs proliferation mediated by Ang II. Following transfection of the synthetic antisense c-src oligodeoxynucleotides (ODNs) wrapped in lipofectin into cultured rat VSMCs, pp60c-src content markedly decreased, pp60c-src kinase activity was only 14.4% of control, while MAPK activity was not significantly changed (P>0.05). When these transfected VSMCs were further stimulated by Ang II, the increase in MAPK activity was only 1.6% of control. These data suggest that pp60c-src is needed for MAPK activation in VSMCs stimulated by Ang II, and pp60c-src may be an important signaling molecule in abnormal proliferation of VSMCs.

Angiotensin II↗