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Biomedical subjects

Zhimin Liu

Publications and source records attributed to Zhimin Liu.

At least 55 records · Page 3Linked to original sources

Immunophenotyping of acute leukemia using an integrated piezoelectric immunosensor array.

Immunophenotyping evaluation is of particular importance for the clinical diagnosis, therapy, and prognosis of acute leukemia. In this paper, an integrated piezoelectric immunosensor array has been developed for the first time to detect the differentiated leukocyte antigens for immunophenotyping of acute leukemia. The probes (crystals) of the array were fabricated with plasma-polymerized n-butylamine film and nanometer-sized gold particles on which the Fab'-SH fragments obtained by the reduction of leukemic lineage-associated monoclonal antibodies (markers) were subsequently immobilized. Investigation results showed that the developed immunosensor array could rapidly identify normal cells from leukemic blasts and define the leukemic blasts within certain phenotypic groups (lineages) by only one analysis of the sample purified or unpurified. It permits the detection of unpurified leukocytes in the dynamic concentration range of 2 orders of magnitude (10(4)-10(6) cells mL(-1)). Up to 17 successive assay cycles with retentive sensitivity were achieved for the probes regenerated with 8 M urea. Moreover, the piezoelectric immunoassay system was applied to evaluate a number of practical specimens with immunophenotyping results in acceptable agreement with those clinically classified. The newly proposed multiparameter analysis technique provides a rapid, simple, and direct alternative tool for clinical immunophenotyping of acute leukemia.

Acute Disease↗

A simple route to micropatterned polymer surfaces.

Polymer surfaces with uniform microscale concave arrays were fabricated by spreading polymer solution on the nonsolvent surface, and the concave-patterned surface could further be used as a template to structure convex-patterned polymer surfaces.

Journal Article↗

Enthalpy of solution of 1,4-naphthoquinone in CO2 + n-pentane in the critical region of the binary mixture: mechanism of solubility enhancement.

The enthalpy of solution (Delta(solv)H(m)) and solubility of 1,4-naphthoquinone in CO(2) + n-pentane were measured at 308.15 K in the critical region of the binary fluid. In order to study the effect of phase behavior of the mixed solvent on Delta(solv)H(m), the experiments were carried out in the supercritical (SC) and subcritical region of the binary solvent. The density of the mixed solvent in different conditions was determined. The isothermal compressibility (K(T)) of the mixed solvent, and the partial molar volume (V(n-pentane)) of n-pentane in the solution were calculated. It was demonstrated that the Delta(solv)H(m) was negative in all conditions. Delta(solv)H(m) is nearly independent of pressure or density in all the solvents in a high-density region, in which compressibility of the solvent is very small; this indicates that the intermolecular interaction between the solvent and the solute is similar to that for liquid solutions. It is very interesting that Delta(solv)H(m) in the mixed SC fluid differs from the Delta(solv)H(m) in mixed subcritical fluids. The absolute value of Delta(solv)H(m) in the mixed SC fluid is close to that in pure SC CO(2) in the high-density region, and is much lower than that in pure SC CO(2) in the low-density region. In the mixed subcritical fluids, the Delta(solv)H(m) is also close to that in the pure CO(2) in the high-density region. However, at the same density, the absolute value of Delta(solv)H(m) in the binary subcritical fluid is larger than that in pure CO(2) in the high-compressible region of the mixed solvent. The main reason for this is that the degree of clustering in the SC solutions is small at the density in which the degree of clustering is large in the subcritical solutions. It can be concluded that solubility enhancement by n-pentane in the mixed SC fluid is entropy driven. In contrast, the solubility enhancement by n-pentane in subcritical fluids is enthalpy driven. The intermolecular interaction in the SC solutions and subcritical solutions can be significantly different even if their densities are the same.

Carbon Dioxide↗

Drug abuse in China.

The drug problem in China reappeared in the late 1980s. At that time, most drug abusers used opium only, with heroin accounting for a very small proportion and its use being limited to border areas in the southwest and rural areas in the northwest. Beginning in the early 1990s, drug abuse spread quickly. The number of registered drug addicts increased from 70,000 in 1990 to one million by the end of 2002. Besides opioids, some "new" kinds of drugs including amphetamines and ketamine have penetrated the country through various channels since 1997. Drug abuse has caused severe problems for both the abusers and society. Three types of treatment settings for detoxification and rehabilitation are available: compulsory detoxification institutions, rehabilitation units through labor, and voluntary detoxification institutions run by sections of public security, justice, and health, respectively. Medical treatment is often combined with psychological counseling and physical training. Pharmaceutical therapy, traditional Chinese medicine, and nonpharmaceutical therapy are utilized for opioid addiction. Drug prevention, especially for young people, is emphasized. NGOs at different levels have all joined in this work. Intervention work was also started in regions where drug abuse and HIV/AIDS problems are serious. Drug abusers are helped to keep drug free after being released from detoxification settings by their communities. Different levels of institutions engaged in research on drug abuse are found in all parts of China.

China↗

[Potential ecological risks of transgenic trees].

A new approach to genetic improvement of trees has been introduced with the birth of gene engineering technique. Compared to that in crops, gene introduction in trees has bigger potential ecological risk in environmental release and extension, because trees, most of which are wind-dispersed, grow on various habitats, have longer life span, and subject to relatively more extensive management. Extensive plantation of transgenic trees may reduce the genetic diversity of the trees concerned. Co-evolution of pests and pathogens is likely to be caused under the pressure of long-term and continuous selection of the trees derived from gene transferring. Escaping of exogenous gene may have a certain kind of influence on fitness of plants naturally generated, and as a result, have influence on species diversity in the natural world. It is not reasonable for China, a developing country, to reject gene introduction as an approach to promote forestry development. It is also important, on the other hand, to take future ecological safety into consideration because it is unwise to get present profit at the cost of future profit. To strengthen basic study on gene transferring, adopting safe management of varieties generated from gene transferring and increasing funds on research and management of transgenic trees are believed to be measures to decrease, to the greatest extent, ecological risks brought about by gene transferring of trees, and to quicken transformation of products of trees derived from gene-transferring into merchandises.

Ecosystem↗

[Soil seed bank in Keerqin meadow grassland under grazing and harvesting].

This study on the size and composition of seed bank and its relationship with vegetation showed in Keerqin meadow grassland, the density of soil seed bank was 6158 +/- 1647 grains x m(-2) under grazing and 8312 +/- 2540 grains m(-2) under harvesting. Under grazing, the seed bank was mainly composed of some dwarf and short-life annuals. The seeds of the annuals and biennials accounted for 81.66% of the seeds in seed bank. The four species with largest proportion of seed bank were Chloris virgata, Chenopodium glaucum, Digitaria cilliaris and Setaria viridis, and the proportions were 38.55%, 15.42%, 14.95%, and 9.83%, respectively. The density of perennials in soil seed bank was 1129 +/- 302 grains x m(-2). Under harvesting, the seeds of annuals and biennials accounted for 68.08% of the seed in seed bank, and the proportion of Setaria viridis was 52.7%. In the harvesting meadow grassland, the seed density of perennials was 2653 +/- 811 grains x m(-2). There was no significant correlation between the seed density in soil and the vegetation under grazing, but a significant correlation between the seed density in soil and the species abundance of vegetation under harvesting (r = 0.76, P < 0.01). The index of Shannon-Wiener and richness of grazing meadow grassland were 2.96 and 2.98, respectively, distinctly smaller than 3.10 and 5.09 of harvesting meadow, which showed that free grazing made the diversity of seed bank decrease easily.

Biodiversity↗

[Effects of sand-burying on seed germination and seedling emergence of six psammophytes species].

This paper studied the effects of sand-burying on the seed germination and seedling emergence of six dominance plants in Keerqin Sandy Land. Six treatments of artificially sand-burying to depths 0, 2, 4, 6, 8, 10 and 12 cm were designed. The results showed that the seed germination of Agriophyllum squarrosum was significantly different (P < 0.05) between different treatments, but that of Artemesia halodendron was only significantly different (P< 0.05) between 2 cm and other burial depths. For other four plants, their seed germination was significantly different (P < 0.05) only between 0 cm and other burial depths. Sand-burying significantly affected the seedling emergence of all plant species. The emergence rate decreased with increasing burial depth. Higher emergence percentages were obtained at 2 and 4 cm burial depths. The species with larger seeds emerged from deeper depth, and the maximum burial depth of seedling emergence was Sophora flavescdens > Atraphaxis manshurica > or = Agriophyllum squarrosum > Hedysarum fruticosum > Bassia dasyphylla > Artemesia halodendron.

Chenopodiaceae↗

[A comparative study on mucilaginous diaspores of four plant species].

A comparative study was conducted on the mucilaginous diaspores of Thymus serpyllum, Plantago depressa, Plantago maritima, and Linum stelleroides. The mucilage amount was estimated by the sand-holding capacity of seed under soaking and watering conditions. Soaking and watering experiments each had 4 treatments. The results indicated that under different soaking time treatments, the mucilage amount of Linum stelleroides and Plantago depressa was of nonsignificant difference, but that of Plantago maritima and Thymus serpyllum was increased with prolonged soaking-time. Under different watering treatments, the mucilage amount of the 4 plant species all had an increasing trend along with the increased water volume. After soaking for 80 min, the weight of sand-holding seed of Plantago maritima was 60 times more than its seed weight, Plantago depressa was 10 times, and Thymus serpyllum and Linum stelleroides was 4-6 times. After watering with 8 mm rainfall, the weight of sand-holding seed of Plantago maritima was 20 times more than its seed weight, Plantago depressa was 6-10 times, and Thymus serpyllum and Linum stelleroides was 2-7 times. In averaging various treatments, the percentage of the sand-holding seed to the total seed of Linum stelleroides, Thymus serpyllum, Plantago depressa and Plantago maritima was 67.7%, 94.5%, 97.7% and 99.5%, respectively.

Adhesives↗

Study on the phase behaviors, viscosities, and thermodynamic properties of CO2/[C(4)mim][PF(6)]/methanol system at elevated pressures.

An apparatus to determine the vapor-liquid equilibria of CO(2)/ionic liquid (IL)/organic solvent multisystems and the viscosity of the liquid phase at elevated pressures has been constructed. The solubility of CO(2) in 3-butyl-1-methyl-imidazolium hexafluorophosphate ([C(4)mim][PF(6)]) and the viscosity of CO(2)-saturated [C(4)mim][PF(6)] have been studied at 313.15, 323.15, and 333.15 K and at pressures up to 12.5 MPa. The phase behavior of CO(2)/[C(4)mim][PF(6)]/methanol ternary mixture and the viscosity of the liquid phases at equilibrium condition have also been determined at 313.15 K and at 7.15 and 10.00 MPa. The partition coefficients of the components in the ternary system are calculated. Peng-Robinson equation of state and some thermodynamic functions are combined to calculate the fugacity coefficients of the components in the system. It demonstrates that the viscosity of the IL-rich phase decreases significantly with increasing pressure of CO(2), and the effect of temperature on the viscosity of CO(2)/IL mixture is not noticeable at high pressure, although the viscosity of the CO(2)-free IL decreases dramatically with increasing temperature. Compressed CO(2) may become an attractive reagent for reducing the viscosity of ILs in many applications. The mole fraction of methanol in the CO(2)-rich phase is much lower than that in the IL-rich phase; this indicates that the interaction between the IL and methanol is stronger than that between CO(2) and methanol. The fugacity coefficient of CO(2) in IL-rich phase is larger than unity, while that of methanol is much small than unity, which further suggests that methanol-IL interaction is much stronger than CO(2)-IL interaction. However, the CO(2)-IL interaction is stronger than the CO(2)-methanol interaction.

Journal Article↗

Organic reactions and nanoparticle preparation in CO(2)-induced water/P104/p-xylene microemulsions.

Nanometer-sized gold particles are synthesized by the reduction of HAuCl(4) with KBH(4) in the CO(2)-induced microemulsion of (EO)(27)(PO)(61)(EO)(27) (P104; EO=ethylene oxide, PO=propylene oxide)/p-xylene/CO(2)/H(2)O. The recovery of gold particles from the microemulsion can be easily accomplished by the venting of CO(2), while the surfactant remains in the organic phase. The effect of the molar ratio of the reductant to HAuCl(4), the concentration of the reactants, and the molar ratio of water to EO segments (W(0)) in the reverse micelles on the size of the gold particles is studied. The hydrolysis of benzoyl chloride (BzCl) and p-nitrophenyl chloroformate (NPhCl) has also been carried out in the microemulsion. The results show that the observed rate constants k(obs) of both substrates increase significantly with W(0), and that W(0) has a larger influence on the hydrolysis of BzCl. The different extents of the influence of W(0) on the two reactions can be ascribed to the different reaction mechanisms and the expected changes in nucleophilicity and polarity of water in the reverse micelles.

Journal Article↗

[The roles of VEGF and C-myc in occurrence, development and metastasis of gallbladder carcinoma].

To investigate the relationship of the expression of vascular endothelial growth factor (VEGF) and C-myc with the occurrence, development and metastasis of gallbladder carcinoma, the expression levels of VEGF and C-myc in gallbladder carcinoma tissue (n = 30) and in normal gallbladder tissue (n = 20) were examined by immunochemistry. Results show that the positive rates of VEGF and C-myc in gallbladder carcinoma tissue were 80% and 63.3% respectively, and 45% and 25% respectively in normal gallbladder tissue. The positive rates of VEGF and C-myc were significantly higher in gallbladder carcinoma than in normal gallbladder tissue. The expression of VEGF and C-myc in gallbladder carcinoma related to the metastasis of gallbladder carcinoma. VEGF and C-myc play important roles in the occurrence, development and metastasis of gallbladder carcinoma.

Adult↗

[Relationships between plant reproductive strategy and disturbance].

Plant reproductive strategy in life history is related to plant adaptation or evolution, ecosystem degradation or restoration, and biodiversity conservation, which are the components of theoretic and applied ecological studies. In this article, several issues concerning the relationships between plant reproductive strategy in life history and disturbance, including Grime's classification of plant reproductive strategies, adaptations of plant vegetative reproduction to disturbances, adaptations of seed morphological traits to disturbance, roles of soil seed bank in disturbance adaptation, and dispersal and germination adaptation of diaspores to disturbance, were briefly reviewed. China's study on relationships between plant reproductive strategy in life history and disturbance in arid zone was also reviewed and discussed.

Ecosystem↗

Expression of vascular endothelial growth factor and matrix metalloproteinase-2 correlates with the invasion and metastasis of hepatocellular carcinoma.

To investigate the relationship of the expression of vascular endothelial factor (VEGF) and matrix metalloproteinase-2 (MMP-2) with the recurrence and metastasis of hepatocellular carcinoma (HCC), the expression of VEGF and MMP-2 in HCC tissue(n = 50) and in normal liver tissue(n = 30) were examined by immunochemistry. The results showed that the positive rates of VEGF and MMP-2 in HCC tissue were 86% and 60% respectively, and in normal liver tissue were 53.3% and 30% respectively. The positive rates of VEGF and MMP-2 in HCC were significantly higher than those in normal liver tissue. The positive rates of VEGF and MMP-2 in HCC with intra- or extra-hepatic metastasis were higher than those of HCC without metastasis. VEGF and MMP-2 play important roles in the invasion and metastasis of HCC.

Adult↗

[Effects of brain-derived neurotrophic factor on H2O2-induced apoptosis of human arterial smooth muscle cell].

OBJECTIVE: To investigate the protective effects of brain-derived neurotrophic factor (BDNF) on hydrogen peroxide (H2O2) induced apoptosis of human arterial smooth muscle cells (SMC). METHODS: The hBDNF cDNA was transfected into the SMC mediated by Lipofect- AMINE, and ectopic expression in SMC was driven by the regulatory elements of I type collagen gene(COLIA1). The cell proliferation was measured with a colorimetric assay based on the cleavage of the tetrazolium salt MTT. Microscopic analysis of cell apoptosis was performed with fluorescent stain of acridine orange (AO). Apoptosis rate of SMC was tested by flow cytometry (FCM). DNA pattern was examined by agarose gel electrophoresis. RESULTS: Exposure of growing SMC to 100-800 mumol/L H2O2 for 24 h remarkably suppressed the cell proliferation. After treatment of the cells with 200 mumol/L H2O2 for 24 h, morphological and biochemical changes of classic apoptosis such as condensation of cytoplasm, fragmentation of the nuclear chromatin, DNA "ladder" pattern after electrophoresis were observed. Yet, the above-mentioned apoptosis changes were not observed and the apoptosis rate was reduced obviously in the BDNF-transfected SMC treated with the same concentration of H2O2. CONCLUSION: H2O2 can induce apoptosis of SMC, but BDNF inhibits H2O2-induced SMC apoptosis markedly and has strong anti-apoptotic activity.

Apoptosis↗

[A comparative study on seed germination of 15 grass species in Keeqin Sandyland].

A laboratory study was made on the germination characteristics of freshly-collected seeds of grass species at the Wulanaodu area of Keeqin Sandyland in Eastern Inner-Mongolia. Of the 15 species examined, 8 species including Clinelymus dahuricus, Cleistogenes squarrosa, Pappophorum boreale, Spodiopogon sibiricus, Phragmites communis, Chloris virgata, Arundinella hirta, Pennisetum alopecuroides had a germination rate of over 80%, but 4 species including Echinochloa hispidula, Hemarthria compressa, Tragus berteronianus and Setaria viridis had a value of less than 10%. Spodiopogon sibiricus, Eragrostis pilosa, Phragmites communis, Chloris virgata, Clinelymus dahuricus, Pappophorum boreale, Digitaria cilliaris and Cleistogenes squrrosa began to germinate within 1-3 days after the test began, while Setaria viridis, Tragus berteronianus and Hemarthria compressa failed to germinate in a period of more than 10 days. For the species such as Digitaria cilliaris, Echinochloa hispidula, Phragmites communis, Eragrostis pilosa and Spodiopogon sibiricus, their germination period was less than 10 days, while Clinelymus dahuricus and Pappophorum boreale had a germination period of more than 20 days. The days required for half the final germination rate to be reached were: 2 days for Chloris virgata, 3 days for Phragmites communis, 4 days for Spodiopogon sibiricus, 5 days for Clinelymus dahuricus and Cleistogenes squarrosa, 7 days for Arundinella hirta and Pappophorum boreale, and 10 days for Pennisetum alopecuriodes. Compared with the Sheffield region in Britain, the Wulanaodu area of Kerqin Sandyland had a higher proportion of annul grasses with a low germination rate and a longer germination period, and the perennial grasses at the Wulanaodu area had an approximately same germination rate, but a longer germination period. During germination, ruderals showed the potential for risk-sharring, and thus, they had a relatively higher disturbance-resistance capacity.

Germination↗