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Biomedical subjects

Y Liu

Publications and source records attributed to Y Liu.

At least 595 records · Page 33Linked to original sources
PubMed2001

Performance of triple ditch: effects of duration and periodic operation programs.

The periodic variation of operation states in triple ditch (BIO-DENITRO process) was investigated in a pilot-scale and a full-scale triple ditch treating raw wastewater containing 70% petrochemical wastewater and 30% domestic wastewater. Mathematical models describing the periodic variation of activated sludge concentrations in each ditch were proposed based on theoretical analysis and were verified in the pilot-scale and full-scale triple ditches respectively. The existence of optimal cycle time and time arrangement of periodic operation programs were demonstrated and discussed according to the mathematical models and the experimental results of the pilot-scale triple ditch operated in four different stages. Four rulers determining the duration and operation programs are suggested.

Bioreactors↗
PubMed2001

Adsorption of heavy metals by EPS of activated sludge.

Extracellular polymeric substances (EPSs) were extracted by high-speed centrifugation at 20,000 G for 30 min from an activated sludge treating municipal wastewater. Each gram of sludge, as measured in volatile suspended solids (VSS), contained 7.3 mg of EPS, including 6.5 mg of protein (EPSp) and 0.8 mg of carbohydrate (EPSc). The EPSp had a mean MW of 2.0 x 105; about 18% of EPSp had MW over 5 x 104 and 16% below 5 x 103. For heavy metal concentrations ranging 10-100 mg/l, EPS on average removed 99% of Zn2+, 98% of Cu2+, 97% of Cr3+, 85% of Cd2+, 69% of Co2+, 37% of Ni2+, and 26% of CrO4(2-). The relative degrees of metal removals were inconsistent with those reported for the activated sludge process. Each mg of ESP had the capacity to remove up to 1.48 mg of Zn2+, 1.12 mg of Cu2+, 0.83 mg of Cr3+, 0.90 mg of Cd2+, 1.10 mg of Co2+, 0.25 mg each of Ni2+ and CrO4(2-). Results suggest the feasibility of recovering ESP from waste sludge for use as adsorbent. Freundlich isotherm correlated satisfactorily with the adsorption data of Ni2+, Cu2+, Cd2+, and CrO4(2-) (R2 ranging 0.89-0.97), whereas Langmuir isotherm correlated satisfactorily with those of Zn2+, Cr3+ and Ni2+ (R2 ranging 0.93-0.96). Both correlated poorly for those of Co2+.

Adsorption↗
PubMed2001

[The survey of polycyclic aromatic hydrocarbons in a habitation air in Hangzhou].

The twelve polycyclic aromatic hydrocarbons(PAHs) were detected in a habitation air air of Hangzhou. The results indicated that the concentrations of PAHs in the habitation air were between 8.237 micrograms/m3 and 14.234 micrograms/m3. The habitation air was seriously polluted by PAHs. The main source of PAHs in the habitation air was from cooking and burning. And the waste gases from vehicular will contribute to it also.

Air Pollutants↗
PubMed2001

[Expression in Escherichia coli and immunogenicity of rotavirus VP7].

Rotaviruses are the single most important cause of severe diarrhea in young children all over the world. VP7 is the major outer capsid and is a primary candidate for inclusion in a subunit or recombinant vaccine. Part of the VP7 gene containing all the three antigenic regions was expressed as a chimeric protein with glutathione S-transferase (GST) in E. coli. The chimeric protein, representing about 30% of the total protein of the recombinant-plasmid-carrying bacteria, reacted with polyclonal antibodies raised against whole virus. Immunization of sero-negative rabbits and mice with purified fusion-protein generated both virus-binding and neutralizing antibodies.

Animals↗
PubMed2001

[Effects of interferon-alpha on recurrence and metastasis of hepatocellular carcinoma after curative resection in nude mice].

OBJECTIVE: To study the effect of interferon-alpha (IFN-alpha) on the recurrence and metastasis of hepatocellular carcinoma (HCC) in nude mice, and to clarify if there is synergistic effect treated by combination of IFN-alpha and all-trans retinoic acid (ATRA). METHODS: The effect of IFN-alpha and/or ATRA on the proliferation of HCC cell lines was measured in vitro. The metastatic model of human HCC in nude mice LCI-D20 was used in present study. Curative resection was performed at 10th day after implantation in 44 nude mice. Drugs were given at the next day after resection. IFN-alpha was administered subcutaneously at doses of 3+/-10(5) U/day, 6+/-10(5) U/day, respectively. ATRA was administered p.o. at a dose of 20 mg/kg/day, and IFN-alpha 6+/-10(5)U/day combined with ATRA 20 mg/kg/day. The mice were sacrificed 35 days after treatment. The recurrent tumor size was measured and the presence of intrahepatic dissemination and lung metastases were recorded. RESULTS: The effect of IFN-alpha and/or ATRA on the proliferation of HCC cells SMMC7721, BEL-7402, BEL-7405, and MHCC97 was not obvious. The combination of IFN-alpha and ATRA had no synergistic effect in vitro. The lung metastatic rate, the liver recurrent rate, the size of main recurrent lesions, the number of intrahepatic disseminating nodules and the largest disseminating nodule of the controlled group was 100%(12/12), 100%(12/12), (1346.3+/-4.2 ) mm(3), 8.2+/-4.4, 864 mm(3), respectively; whereas it was 0, 87.5%(7/8), (8.7+/-2.9) mm(3), 2.3+/-0.6, and 7.8mm(3), respectively in the IFN-alpha 3+/-10(5) U/day treated group(P<0.05); 0, 12.5%(1/8), 0.5mm(3), 2, 0.5 mm(3) in the IFN-alpha 6+/-10(5)U/day treated group(P<0.05); 0, 12.5%(1/8), 1 mm(3), 2.5+/-0.7, 8 mm(3) in the IFN-alpha 3+/-10(5) U/day and ATRA treated group(P<0.05); 87.5%, 100%, (1472.6+/-5.6) mm(3), 7.3+/-3.8, 768.5 mm(3) in the ATRA treated group (P>0.05). CONCLUSIONS: IFN-alpha has an inhibitory effect on intrahepatic recurrence and lung metastasis of human HCC after curative resection in nude mice, and the effect is enhanced with increasing dose. IFN-alpha and ATRA have no synergistic effect according to in vivo and in vitro test. ATRA has no effect on recurrence and metastasis of HCC.

Animals↗
PubMed2001

[Cloning and sequence analysis of truncated S gene from circulation of patients with chronic hepatitis B virus infection].

OBJECTIVE: To find different mutated status of HBV DNA in circulation from chronic HBV patients. METHODS: Specially designed primers and polymerase chain reaction method were applied to amplify the whole S gene of HBV from the serum of 2 patients. After being sequenced, 4 clones were compared with HBV adr subtype (China strain) to identify the mutant sites. RESULTS: Sequencing results implied that there was a truncated large/middle S gene in the serum of the patients. Besides that, HBsAg and HBV DNA polymerase defective clones were also detected. CONCLUSIONS: Truncated middle S gene is found in the circulation of patients with chronical HBV infection, suggestive of a poor prognosis.

Cloning, Molecular↗
PubMed2001

[The effects of iron compounds on SO2 and NO emissions in coal combustion process].

The effects of ferric/ferrous chlorides and ferric oxide on emissions in Tongchuan coal combustion process were experimentally investigated using thermogravimetric analyzer. The results show that all iron compounds used in the experiments, namely FeCl3, FeCl2 and Fe2O3 can change the emissions of SO2 and NO, but with different mechanisms and different magnitudes. FeCl3 plays the roles of both a catalyst and an absorbent in the conversions from coal-S to SO2 and from coal-N to NO. Due to the catalysis the activation energy required for the formation of SO2 and NO is reduced, the rates of the reactions leading to SO2 and NO increased. The catalysis is concerned with the forms of coal sulfur. Due to the absorption FeCl3 reacts with SO2 to produce FeSO4 [symbol: see text] Fe2(SO4)3. In addition FeCl3 can decrease the emissions of CO, i.e., the combustion characteristics can be changed. The effects of FeCl2 on the emissions of SO2, NO and CO are similar to those of FeCl3, but weaker. Fe2O3 can also decrease the SO2 and NO emissions to some extent, but has negligible influence on CO emission.

Catalysis↗
PubMed2001

[Study on the noninvasive measurement of cerebral oxygen saturation and cerebral phronetal function].

With the use of Near-infrared spectroscopy(NIRS), the noninvasive measurement of cerebral oxygen concentration can be achieved in vivo based on the Lambert-Beer Law. In this paper, we discuss the possibility of studying higher brain functions through a combination of cerebral oxygen saturation and cerebral function measurement. Event-related experiments are introduced to measure the cerebral phronetal function. Time domain curves show sight differences among these experiment results. However, with the aid of DFT, experiment data of all five human volunteers show that the frequency near 20 Hz or 40 Hz is evoked depending on the difficulty of the mental tasks. The results demonstrate the feasibility of cerebral function studies by means of cerebral oxygen saturation measurement analysis in the frequency domain.

Adult↗
PubMed2001

[Preparation and application of polylactide].

Polylactide and its copolymers are polymer materials that can be degraded by organisms and have good biocompatibility. Since the polymer materials have no toxicity and can be absorbed, greater and greater attention has been paid to the related researches and development, and they are increasingly applied in various areas, especially medicine and pharmacy. There are three methods for preparing polylactide and its copolymers. The tests for evaluating the degraded property of polylactide and its copolymers have been existing for more than thirty years, but all of them have their defects. The property and technological level of polylactide and its copolymers remain to be improved for use in some areas. Once the manufacture of poly lactide is industrialized, it can be of wide application in the fields of medicine and degraded plastics.

Biocompatible Materials↗
PubMed2001

[Progress in studies on the mechanism of substance addiction in central nervous system].

The mechanism of substance addiction in the central nervous system is the key point to solve the problem of drug addiction in clinical prophylaxis and treatment, but it has been obscure so far. Previous researches in this field suggested that the higher brain function of the learning and memory might be pivotal in understanding the mechanism of substance addiction. It is the intent of this review to integrate and analyze the substance addiction and the learning and memory in an attempt to shed light on the strategies to conduct further studies in this field.

Central Nervous System↗
PubMed2001

[Acetylcholine and A23187 stimulate epinephrine secretion of isolated rat adrenal medulla cells in vitro].

Acetylcholine and A23187, two acetylcholinergic agonists, were used to induce the stimulus-secretion coupling of the isolated rat adrenal medulla cells. Morphometry of numerical density and electron probe X-ray quantitative microanalysis were adopted to measure the alterations in the number and calcium content of chromaffin granules in adrenal medulla cells during the agonist treatment. Secretion of epinephrine was detected by the high performance liquid chromatography (HPLC). It was found that the Ca content of the isolated rat adrenal medulla chromaffin granules dropped significantly after a 10-min incubation with the agonists, whereas the number of chromaffin granule decreased slowly during the agonist treatment and the epinephrine concentration raised significantly after a 20-min incubation with the agonists. The decrease of granule Ca content occurred earlier than the increase of epinephrine concentration, suggesting that the calcium released from chromaffin granule may in part account for the induced cell secretion.

Acetylcholine↗
PubMed2001

Clinical outcome of patients with previous myocardial infarction and left ventricular dysfunction assessed with myocardial (99m)Tc-MIBI SPECT and (18)F-FDG PET.

UNLABELLED: Myocardial viability was assessed by (99m)Tc-methoxyisobutylisonitrile (MIBI) SPECT and (18)F-FDG PET to evaluate the prognosis and treatment strategy of patients with myocardial infarction (MI) and left ventricular (LV) dysfunction. METHODS: One hundred twenty-three consecutive patients with previous MI and LV dysfunction (LV ejection fraction [EF], 35% +/- 6% [mean +/- SD]) who underwent (99m)Tc-MIBI SPECT and FDG PET were followed-up for 26 +/- 10 mo (mean +/- SD). Distributions of the 2 radiotracers in myocardial segments were classified into 2 patterns: myocardial perfusion-metabolism mismatch (MM) and match (M). LV EF and LV end-diastolic diameter (EDD) were measured by echocardiography at baseline, 3 mo (Pos1), and 6 mo (Pos2) after revascularization. Cardiac death, acute MI, unstable angina, and late revascularization (>3 mo) experienced by the patients during follow-up were defined as cardiac events. RESULTS: Sixty-seven patients underwent revascularization and 56 patients were treated medically. Of the 72 patients with > or =2 MM segments, 42 underwent revascularization (group A1) and 30 were treated medically (group A2). Of the 51 patients with <2 MM segments, 25 underwent revascularization (group B1) and 26 were treated medically (group B2). The 4 groups had similar baseline characteristics and rest LV EF. After revascularization, EF (mean +/- SD) increased in group A1 from 36% +/- 5% to 44% +/- 8% (P < 0.0001) in Pos1 and to 51% +/- 9% (P < 0.0001) in Pos2. EDD (mean +/- SD) decreased from 62 +/- 8 mm to 56 +/- 5 mm (P < 0.001) in Pos1 and to 55 +/- 5 mm (P < 0.001) in Pos2. However, EF and EDD were unchanged in group B1 (P > 0.05). During the follow-up, 22 patients (17.9%) suffered from cardiac events, including 11 cardiac deaths, 4 acute MI, 6 late coronary artery bypass grafting, and 1 unstable angina pectoris. The cardiac event rate in group A2 (50%) was significantly higher than that of groups A1 (2.4%; chi(2) = 23.08; P < 0.0001), B1 (12%; chi(2) = 8.94; P = 0.003), and B2 (11.5%; chi(2) = 9.45; P = 0.002). CONCLUSION: Assessment of myocardial viability using hybrid (99m)Tc-MIBI SPECT and FDG PET can predict the clinical outcome and is helpful to decision making in the treatment strategy of patients with MI and LV dysfunction. Revascularization can improve the LV function and clinical outcome of patients with >2 viable myocardial segments.

Aged↗
PubMed2001

Femtomolar concentrations of dynorphins protect rat mesencephalic dopaminergic neurons against inflammatory damage.

The hallmark of Parkinson's disease is the death of nigral dopaminergic neurons, and inflammation in the brain has been increasingly associated with the pathogenesis of this neurological disorder. Dynorphins are among the major opioid peptides in the striato-nigral pathway and are important in regulating dopaminergic neuronal activities. However, it is not clear whether dynorphins play a role in the survival of nigral dopaminergic neurons. We have recently demonstrated that lipopolysaccharide (LPS) activates the brain immune cells microglia, in vitro and in vivo, to release neurotoxic factors to degenerate dopaminergic neurons. The purpose of this study was to explore the neuroprotective effect of dynorphins in the inflammation-mediated degeneration of dopaminergic neurons in rat midbrain neuron-glia cultures. LPS-induced neurotoxicity was significantly reduced by treatment with ultra low concentrations (10(-13)--10(-15) M) of the kappa-opioid receptor agonist dynorphin A (1--17) or the receptor binding ineffective [des-Tyr(1)]dynorphin A (2--17), but not by U50488, a synthetic kappa-receptor agonist. The glia-mediated neuroprotective effect of dynorphins was further supported by the finding that femtomolar concentrations of dynorphins did not prevent the killing of dopaminergic neurons by 6-hydroxydopamine. However, ultra low concentrations of dynorphins inhibited LPS-induced production of superoxide. These results suggest a glia-mediated and conventional opioid receptor-unrelated mechanism of action for the neuroprotective effect of ultra low concentrations of dynorphins. Understanding the underlying mechanisms of action should further define the roles of dynorphins in the regulation of dopaminergic neurons and help devise novel strategies to combat neurodegenerative diseases.

Animals↗
PubMed2001

[IFN-r/IL-4 expression in peripheral blood mononuclear cells of the patients with chronic severe hepatitis].

OBJECTIVE: To understand the expressions of interferon-r (INF-r) and interleukin-4 (IL-4) in peripheral blood mononuclear cells (PBMCs) of the patients with chronic severe hepatitis (CSH). METHODS: PBMCs from the patients with CSH were separated routinely and stimulated by PMA/Ionomycin/Monensin. The production of IFN-r/IL-4 by CD4+ T cells in PBMC was determined by fluorescence activated call sorting (FACS) analysis and fluorescence-quantitative PCR assay for quantification of HBV DNA. RESULTS: The percentage of IFN-gamma-producing T cells in CD4+ T cells was higher in patients with CSH (7.2%-26.3%) than in normal controls (2.2%-11.9%) (P<0.01). The percentage of Th1 cells increased significantly with the raise of hepatic inflammation activity. The percentage of IL-4-producing T cells in CD4+ T cells did not differ significantly between patients with CSH and normal controls. The quantification of HBV DNA decreased significantly with the increase of the percentage of IFN-gamma-producing T cells. CONCLUSIONS: Th1 cell is associated with hepatic inflammatory activity and IFN-gamma depresses HBV replication.

Adult↗
PubMed2001

Building a controlled health vocabulary in Japanese.

OBJECTIVES: This study is aimed at developing a controlled clinical vocabulary for use in electronic patient record (EPR) systems. METHODS: In this paper, we propose a model for building the vocabulary. The model is composed of a Canonical Term Dictionary, an Atom Dictionary, a Composite Atom Dictionary, and an Index. Parsing and composing functions are included in this model. Canonical terms were extracted from reference terminologies. Atoms were extracted from the Canonical Term Dictionary and reduced to a set from which the Composite Atom Dictionary can be built. The index was built to link these two dictionaries. For testing the model, we compiled a sample vocabulary and applied the model to a SNOMED translation system (English to Japanese) and a term similarity estimation system. RESULTS: The sample vocabulary consisted of 15,600 atomic terms and 4,450 composite terms. 33,441 SNOMED terms were translated by the SNOMED translation system. The system gave adequate Japanese candidates in 56.3% of cases. The similarity estimation system found an average of 5.4 candidates when the equality ratio was over 50%. CONCLUSIONS: The trial applications produced good results. The model seems promising for building a standard clinical vocabulary system. This system can be applied in certain other Asian countries, such as China and Korea.

Algorithms↗
PubMed2001

[Identification of notoginseng(Panax notoginseng) and its adulterants using DNA sequencing].

OBJECTIVE: To analyze the nuclear ribosomal RNA small subunit (18S rRNA) and chloroplast matK gene sequence of notoginseng (Panax notoginseng) in order to provide molecular evidence for its genuine origin identification. METHODS: To sequence 18S rRNA and matK genes of Panax notoginseng and its four adulterants such as P. japonicus, Curcuma phaeocaulis, C. wenyujin, C. kwangsiensis using PCR direct sequencing and to detect their variation of sequences. RESULTS: The sequence length of notoginseng and its adulterants is 1809-1811 bp for 18S rRNA gene and 1259-1548 bp for matK gene, respectively. Multiple sequence alignment shows that there are much sequence variation between notoginseng and its adulterants. CONCLUSION: DNA sequencing is an accurate and reliable method in origin identification of the genuine notoginseng.

Amino Acid Sequence↗