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Yin Li

Publications and source records attributed to Yin Li.

At least 73 records · Page 4Linked to original sources
PubMed2004

Mathematical modeling for prediction of endo-xylanase activity and arabinoxylans concentration during mashing of barley malts for brewing.

A mathematical model describing the degradation of arabinoxylans by endo-xylanase during mashing process was developed. Endo-xylanase activities and arabinoxylans concentrations in laboratory scale mashing process at different temperature profiles were measured and then used for identifying the model parameters for Harrington barley malt. The modeling errors range for the final concentration of arabinoxylans in wort was -4% to +11.9%. The model developed was also used for predicting the other three different malts mashing processes in laboratory scale, and the prediction errors ranged from -9.5% to +13.6%. The model prediction accuracy for industrial scale mashing process was lower than that in laboratory scale. The simulation results showed that, a lower concentration of arabinoxylans could be achieved when maintaining the mashing-in at 45 degrees C and prolonging the mashing-in time.

Computer Simulation↗
PubMed2004

Stereo reconstruction from multiperspective panoramas.

A new approach to computing a panoramic (360 degrees) depth map is presented in this paper. Our approach uses a large collection of images taken by a camera whose motion has been constrained to planar concentric circles. We resample regular perspective images to produce a set of multiperspective panoramas and then compute depth maps directly from these resampled panoramas. Our panoramas sample uniformly in three dimensions: rotation angle, inverse radial distance, and vertical elevation. The use of multiperspective panoramas eliminates the limited overlap present in the original input images and, thus, problems as in conventional multibaseline stereo can be avoided. Our approach differs from stereo matching of single-perspective panoramic images taken from different locations, where the epipolar constraints are sine curves. For our multiperspective panoramas, the epipolar geometry, to the first order approximation, consists of horizontal lines. Therefore, any traditional stereo algorithm can be applied to multiperspective panoramas with little modification. In this paper, we describe two reconstruction algorithms. The first is a cylinder sweep algorithm that uses a small number of resampled multiperspective panoramas to obtain dense 3D reconstruction. The second algorithm, in contrast, uses a large number of multiperspective panoramas and takes advantage of the approximate horizontal epipolar geometry inherent in multiperspective panoramas. It comprises a novel and efficient 1D multibaseline matching technique, followed by tensor voting to extract the depth surface. Experiments show that our algorithms are capable of producing comparable high quality depth maps which can be used for applications such as view interpolation.

Algorithms↗
PubMed2004

[Long-term efficacy of radiotherapy on children with nasopharyngeal carcinoma].

BACKGROUND & OBJECTIVE: Nasopharyngeal carcinoma (NPC) in children is a particular type of NPC with poor prognosis. This study was to analyze long-term treatment efficacy, and relevant factors influencing prognosis of NPC in children. METHODS: From Jan. 1975 to Dec. 1995, 47 children,7-14 years old, with NPC diagnosed by pathology received radiotherapy in our hospital. Radiation doses were 52-74 Gy/6-13 weeks [(64.68+/-5.68) Gy] in nasopharynx, and 46-73 Gy/5-13 weeks [(57.77+/-5.86) Gy] in neck; 21 received 1-3 cycles of chemotherapy (cisplatin, bleomycin, 5-fluoroucil, vincristine, and cyclophosphamide) before radiotherapy. Survival rate was calculated by Kaplan-Meier method, and analyzed by log-rank test with SPSS 10.0 software. RESULTS: The 1, 3, 5-year survival rates of 47 patients were 72.3%, 53.2%, and 40.4%, respectively. Clinical stage (P=0.046), mode of biopsy (P=0.024), radiation dose in nasopharynx (P=0.049), and short-term efficacy (P=0.005) correlated with prognosis of these patients. The average height of 15 male children with NPC who survived for more than 5 years was (161.5+/-1.23) cm. Among 3 female children with NPC who survived for more than 5 years, 2 had menstruation disturbance. CONCLUSIONS: Clinical stage, mode of biopsy, radiation dose in nasopharynx, short-term efficacy may influence prognosis of NPC in children. Radiation-induced long-term sequelae of NPC in children should not be overlooked.

Adolescent↗
PubMed2004

[Cloning of cDNA fragments related to adventitious root formation from mango cotyledon section].

Two cut surfaces of mango cotyledon (distal and proximal cut surfaces) showed different capability of adventitious root formation, only proximal cut surface could be induced to form the roots and the distal cut surface did not. cDNA fragments related to adventitious root formation from the cut sections were isolated with suppressive subtractive hybridization. The forward substracted cDNA library was constructed using the cDNAs of distal (non-rooting) cut surface as driver and the cDNAs of proximal (rooting) cut surface as tester. Six positive clones were obtained by Virtual Northern blots. In this study, the putative up-regulated genes showed by sequence analysis were reported in mango for the first time, the deduced proteins among the positive clones were homologous to transporters, transcriptional regulators and enzymes.

Blotting, Northern↗
PubMed2004

[Thermo-alkali-stable catalase from Thermoascus aurantiacus and its potential use in textile bleaching process].

The effect of growth and fermentation conditions on the production of catalase by T. aurantiacus WSH 03-01 was investigated in shaking flasks. Catalase activity reached 1594 u/mL when the culture was grown on a complex carbon source containing 20 g/L dextrin and 1% (V/V) ethanol, which was 23% higher than the sum produced on 20 g/L dextrin and 1% (V/V) ethanol, respectively. It was concluded that dextrin might act as a major carbon source in the complex, while ethanol was rather a stimulator than a carbon source. The stimulation effect of ethanol on catalase production was postulated to be two aspects; catalase-dependent alcohol metabolism is activated by acute alcohol, thus more catalase need to be synthesized for that use, named direct induction. As for indirect induction, which may result from little amount of H2O2 generation in process of NADH regeneration in respiratory chain. Peptone was shown to be a favorable nitrogen source for catalase production and its optimum concentration was found to be 10 g/L. Catalase production by T. aurantiacus WSH 03-01 was further improved by optimizing the initial pH, volume of medium in flasks as well as the concentration of external H2O2. Under the optimum culture conditions, the activity of catalase reached 2762 u/mL, which was nearly 6.8 times higher than that of the initiate conditions. Furthermore, the potential application of this novel catalase in the treatment of textile bleaching effluents was evaluated. Thermo-and alkaline stability of this catalase was compared with the commercial available catalases produced from bovine and Aspergillus niger. The crude enzyme from T. aurantiacus WSH 03-01 showed stronger stabilities at (70 degrees C, 80 degrees C, 90 degrees C) and (pH 9.0, pH 10.0, pH 11.0) than the other two types of catalases, indicating a great application potential in the clean production process of textile industry.

Catalase↗
PubMed2004

[Addition of TCA cycle intermediates enhances pyruvate production].

The capability of utilizing the intermediates of TCA-cycle as the sole carbon source by the multi-vitamin auxotrophic yeast Torulopsis glabrata CCTCC M202019 under the conditions of vitamins limitation was demonstrated. Furthermore, the colony numbers grown on medium supplemented with glucose, acetate and one of the intermediates of TCA-cycle was higher than that of medium used glucose and acetate or medium used one of the intermediates of TCA-cycle carbon source. Among the intermediates of TCA-cycle used in this study, oxaloacetate was the best carbon source for the yeast and it was found that its presence stimulated the conversion of acetate to acetyl-CoA. In batch fermentation with glucose medium, the addition of 10 g/L of oxaloacetate improved the dry cell weight from 11.8 g/L to 13.6 g/L, and the productivity of pyruvate from 0.96 g x L(-1) x h(-1) to 1.19 g x L(-1) x h(-1), a 24% increase after 56 h growth. The yield of pyruvate on glucose was also improved as well, from 0.63 g/g to 0.66 g/g.

Candida glabrata↗
PubMed2004

[The decrease of the activity of electron transfer chain of Torulopsis glabrata enhanced pyruvate productivity].

Torulopsis glabrata CCTCC M202019 was mutated by ethidium bromide to screen for respiratory-deficient mutants. Seven mutants that produced pyruvate higher than that of the parent were subjected to the tests of the capability assimilating fermentable substrate (glucose) and non-fermentable substrates (glycerol and acetate) to characterize true respiratory-deficient mutants. Mutants RD-16, RD-17 and RD-18 were unable to assimilate acetate or glycerol and were therefore identified as respiratory-deficient mutants. Compared to the parent strain, the growth the intracellular ATP content of those mutants decreased by 21% - 29% and 15% - 21%, respectively, while the glucose consumption per cell and the pyruvate production per cell of those mutants were enhanced by 20.7% - 30.7% and 30.7% - 55.5%, respectively. Qualitative analysis of cytochromes involved in electron transfer chain showed that mutants RD-16 and RD-18 lacked both cytochrome aa3 and b, while mutant RD-17 lacked cytochrome b. Enzymes analysis indicated that the activities of ATPase, succinate-cytochrome c reductase (complex I ), complex I + III , complex II + III, and complex IV of those mutants decreased by 14.6% - 22.2%, 34% - 41%, 38.6% - 52.6%, 21% - 25%, and 150% - 630%, respectively. However, increased glucose consumption per cell was not observed in those mutants, which might be due to that the NADH generated in glycolysis can not be completely oxidized via electron transfer chain. To avoid the accumulation of NADH, 2.1 mmol/L acetaldehyde was added to the culture broth of mutant RD-17 at 26h of fermentation. Using this strategy, the amount of pyruvate produced increased by 21.6% while the fermentation time was shortened from 62h to 48h.

Acetaldehyde↗
PubMed2003

Fas-mediated apoptosis is dependent on wild-type p53 status in human cancer cells expressing a temperature-sensitive p53 mutant alanine-143.

The p53 mutant 143Ala is a human temperature-sensitive mutant with two conformational states. To definitively determine whether the Fas signal transduction pathway and the function of the pathway are dependent on p53 status, we have established stable transfectants of p53 mutant 143Ala in two human cancer cell lines: H1299 (lung cancer line) and PC-3 (prostate cancer line), the native state of which contains null p53 status and can grow at 37 degrees C and 32.5 degrees C. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell cycle analysis showed inhibition of the growth of cells overexpressing p53 mutant 143Ala in the wild-type p53 form at 32.5 degrees C because of induction of G0/G1 arrest. Transfected cells had increased protein expression of p21, Fas, and MDM2 at the wild-type p53 conformation at 32.5 degrees C, but not in the mutant p53 form at 37 degrees C. However, there was no change in protein expression of FADD, FAP-1, Bcl-2, or Bax at 32.5 or 37 degrees C. Assays for apoptosis demonstrated that anti-Fas antibody CH-11 and FasL induced apoptosis only in cells that overexpress p53 mutant 143Ala at 32.5 degrees C with the wild-type p53 form. Both caspase-3 and caspase-8 activities were increased by anti-Fas antibody CH-11 only in cells at 32.5 degrees C with wild-type p53. Our results demonstrated that Fas-mediated apoptosis in H1299 and PC-3 cells expressing p53 mutant 143Ala occurred only with the wild-type p53 phenotype. These results support the hypothesis that Fas-mediated apoptosis is dependent, at least partially, on the presence of a functional wild-type p53 state. This model may be a useful tool for dissecting the specific interactions between wild-type p53 and the Fas signal transduction pathway in human cancer cells.

Adenocarcinoma↗
PubMed2003

Application of a two-stage temperature control strategy for enhanced glutathione production in the batch fermentation by Candida utilis.

In batch culture for glutathione production with Candida utilis, a higher temperature (30 degrees C) was required to hasten cell growth while a lower temperature (26 degrees C) was needed to increase the production of glutathione. A two-stage temperature control strategy was used to enhance both the yield and the productivity of glutathione. As a result, glutathione production was increased by 5% and 23% of that at 26 degrees C and 30 degrees C, respectively, and the intracellular glutathione content reached 2.5% (w/w).

Bioreactors↗
PubMed2003

Glutathione protects Lactococcus lactis against oxidative stress.

Glutathione was found in several dairy Lactococcus lactis strains grown in M17 medium. None of these strains was able to synthesize glutathione. In chemically defined medium, L. lactis subsp. cremoris strain SK11 was able to accumulate up to approximately 60 mM glutathione when this compound was added to the medium. Stationary-phase cells of strain SK11 grown in chemically defined medium supplemented with glutathione showed significantly increased resistance (up to fivefold increased resistance) to treatment with H2O2 compared to the resistance of cells without intracellular glutathione. The resistance to H2O2 treatment was found to be dependent on the accumulation of glutathione in 16 strains of L. lactis tested. We propose that by taking up glutathione, L. lactis might activate a glutathione-glutathione peroxidase-glutathione reductase system in stationary-phase cells, which catalyzes the reduction of H2O2. Glutathione reductase, which reduces oxidized glutathione, was detectable in most strains of L. lactis, but the activities of different strains were very variable. In general, the glutathione reductase activities of L. lactis subsp. lactis are higher than those of L. lactis subsp. cremoris, and the activities were much higher when strains were grown aerobically. In addition, glutathione peroxidase is detectable in strain SK11, and the level was fivefold greater when the organism was grown aerobically than when the organism was grown anaerobically. Therefore, the presence of glutathione in L. lactis could result in greater stability under storage conditions and quicker growth upon inoculation, two important attributes of successful starter cultures.

Culture Media↗
PubMed2003

Visceral fat: higher responsiveness of fat mass and gene expression to calorie restriction than subcutaneous fat.

Visceral fat accumulation is accompanied by several metabolic disorders. Here, we investigate the improvement of visceral fat accumulation in the early phase of diet. Hyperlipidemic obese patients received a low-calorie diet (1000 kcal/day) for 14 days. Visceral and subcutaneous fat accumulation was analyzed using ultrasonography. After 14 days of the diet, the average visceral fat of obese patients obviously decreased (P < 0.05), as well as the visceral fat-related secreted proteins, whereas subcutaneous fat did not decrease in these patients. These results show that visceral fat is reduced significantly in the early phase of diet therapy in humans. Therefore, to clarify its mechanism, we analyzed the expression of lipid metabolism-related genes in visceral and subcutaneous fat using obese rats. The Long-Evans Tokushima Otsuka (LETO) rats, as an obese model, were divided into two groups: fasting and non-fasting. The gene expressions in visceral and subcutaneous fat were measured by reverse transcriptase-polymerase chain reaction (RT-PCR). The expression of beta(3)-adrenergic receptor (AR), hormone sensitive lipase (HSL), peroxisome proliferator-activated receptor (PPAR)-gamma, and uncoupling protein (UCP)-2 genes increased by 3.2-, 2.3-, 2.2-, and 2-fold in visceral fat (P < 0.01), but remained almost unchanged in subcutaneous fat. Taken together, the responsiveness of lipid metabolism-related genes to fasting is more sensitive in visceral fat than in subcutaneous fat in rats, suggesting that the different responsiveness to calorie restriction in fat tissues is due to the different induction of metabolism-related gene expression.

Adipose Tissue↗
PubMed2003

Decreased expression of adrenomedullin during adipocyte-differentiation of 3T3-L1 cells.

Adrenomedullin (AM) is a potent vasodilator peptide which has an inhibitory action on insulin secretion. Resistin is a novel peptide specifically secreted from adipocytes, and implicated in insulin resistance. We studied the expression of AM and resistin in 3T3-L1 adipocytes and preadipocytes by Northern blot analysis and radioimmunoassay. Immunoreactive-AM was detected in the culture media of 3T3-L1 preadipocytes and adipocytes, with higher concentrations found in preadipocytes. Northern blot analysis showed that AM mRNA was expressed in 3T3-L1 preadipocytes but was undetectable in adipocytes. In contrast, resistin mRNA was expressed in 3T3-L1 adipocytes, whereas it was not detected in 3T3-L1 preadipocytes. The present study thus showed that AM expression was decreased, and resistin expression increased, during adipocyte-differentiation of 3T3-L1 cells.

3T3 Cells↗
PubMed2003

Differential expression of adrenomedullin and resistin in 3T3-L1 adipocytes treated with tumor necrosis factor-alpha.

DESIGN: It has recently been shown that deficiency of adrenomedullin (AM), a potent vasodilator peptide, leads to insulin resistance. We studied expression of AM in NIH 3T3-L1 adipocytes and compared it with expression of resistin, an adipocyte-derived peptide hormone that is proposed to cause insulin resistance. Moreover, we studied the effects of tumor necrosis factor-alpha (TNF-alpha), a known mediator of insulin resistance, on the expression of AM and resistin in 3T3-L1 adipocytes. METHODS: 3T3-L1 cells were induced to differentiate to adipocytes by insulin, dexamethasone and 3-isobutyl-1-methylxanthine. Expression of AM mRNA and resistin mRNA was examined by Northern blot analysis. Immunoreactive AM in the medium was measured by RIA. RESULTS: AM mRNA was expressed in preadipocytes, but barely detectable in adipocytes. Immunoreactive AM was detected in the medium of both preadipocytes and adipocytes, with about 2.5 times higher levels found in preadipocytes. In contrast, resistin mRNA was expressed in adipocytes, whereas it was not detected in preadipocytes. Treatment with TNF-alpha increased AM expression in both adipocytes and preadipocytes, whereas it decreased resistin mRNA levels in adipocytes. CONCLUSIONS: The present study has shown that AM expression was down-regulated and resistin expression was up-regulated during adipocyte differentiation of 3T3-L1 cells. TNF-alpha acted as a potent negative regulator of resistin expression and a potent positive regulator of AM expression in adipocytes, raising the possibility that in addition to its known actions in causing insulin resistance, TNF-alpha may also have actions against insulin resistance through AM and resistin.

1-Methyl-3-isobutylxanthine↗
PubMed2003

[The expression of cell adhesion molecule Syndecan-1 and E-candherin in laryngeal cancer].

OBJECTIVE: To observe Syndecan-1 and E-candherin expression and their relationship with clinico-pathologic factors in primary laryngeal squamous cell carcinoma(LSCC). METHOD: Syndecan-1 and E-candherin proteins were determined with immunohistochemical technique. RESULT: In invasive LSCC the expression of these two adhesion molecules were very similar. Both diminished with decreasing cell differentiation, lacked often in poorly differentiated tumors. And their expression were significantly correlated with each other. CONCLUSION: Our results suggest that Syndecan-1 and E-candherin expression correlates significantly with the histological differentiation grade of the tumors and the tumors size. They may play important roles in the pathogensis and the development of LSCC.

Adult↗
PubMed2003

[Kinetic models for the effect of temperature on batch glutathione fermentation by Candida utilis].

Glutathione (L-gamma-glutamyl-L-cysteinylglycine), one of the major non-protein thiol compounds, is widely distributed in living cells and plays an important role in maintaining the normal redox environment of cells as an antioxidant. In the production of glutathione by fermentation, temperature is one of the most important environmental factors that affect the yield and the productivity of glutathione. Here the effect of temperature, varied from 24 degrees C to 32 degrees C, on the batch fermentation of glutathione in a 7 L stirred fermenter by Candida utilis WSH 02-08 was investigated. It was found that cell growth was hastened along with the increase of temperature. The maximum dry cell weight was achieved approximately 16 g/L under various temperatures, as soon as the glucose was exhausted. The effect of temperature on glutathione production was different from that on cell growth: the lower the temperature, the higher the glutathione production, i.e. the maximum glutathione concentration at 32 degrees C (235 mg/L) was only 75% and 64% of that at 30 degrees C and 26 degrees C, respectively. The maximum average specific growth rate (0.13 h(-1)) was achieved at 30 degrees C while the maximum glutathione concentration (366 mg x L(-1)) and the maximum intracellular glutathione content (2.3%) were obtained at 26 degrees C. Therefore, the optimum temperatures for cell growth and glutathione production are quite different in the batch fermentation. A modified Logistic equation was successfully applied to estimate the kinetics of cell growth. The maximum specific growth rate and the substrate inhibition constant, calculated from this equation, were both increased along with the temperature. In addition, the glutathione fermentation by C. utilis WSH 02-08 under various temperatures was proven to be a partial growth-associated process by estimating the process with the Luedeking-Piret equation. Based on the estimated parameon the estimated parameters, the effect of temperature on the kinetics of cell growth was further studied. An equation, dX / dt = [0.0224(T + 1.7)]2 X(1-X/Xmax) / 1 + S/ {8.26 x 10(6) x exp [-31477/R/(T+273)]}, was developed and applied to interlink the relationship between biomass concentration and temperature as well as substrate concentration in the batch glutathione fermentation. The experiment results showed that this model could predict the growth pattern very well.

Candida↗
PubMed2003

[Effects of dissolved oxygen and pH on Candida utilis batch fermentation of glutathione].

The effects of dissolved oxygen (DO) and pH on glutathione batch fermentation by Candida utilis WSH-02-08 in a 7 liters stirred fermentor were investigated. It was shown that DO concentration is an important factor in glutathione production. With the initial glucose concentration of 30 g/L and a 5 L/min air flow rate, and the agitation rate less than 250 r/min, the DO concentration was not sufficient to satisfy the oxygen requirement during the fermentation. With an agitation rate of more than 300 r/min, the cell growth and glutathione production were enhanced significantly, with the dry cell mass and glutathione production were 20% and 25% higher than that at 200 r/min. When C. utilis WSH 02-08 was cultivated in a batch process without pH control, cell growth and glutathione production were inhibited, likely due to a dramatic decrease in the pH. Intracellular glutathione leakages were observed when the pH was 1.5 or less. To assess the effect of pH on glutathione production, six batch processes controlled at pH 4.0, 4.5, 5.0, 5.5, 6.0 and 6.5 were conducted. The yield was highest at pH 5.5, when the dry cell mass and yield were 27% and 95% respectively higher than fermentation without pH control. The maximal intracellular glutathione content (2.15 %) was also achieved at the pH. To improve our understandings on the effect of pH on the batch glutathione production, a modified Logistic equation and Luedeking-Piret equation were used to simulate cell growth and glutathione production, respectively, under different pH. Based on the parameters obtained by the nonlinear estimation, kinetic analysis was performed to elucidate the effect of pH on the batch glutathione production. The process controlled at pH 5.5 was proven to be the best due to the higher value of K(I) (substrate inhibitory constant in the Logistic equation), lower value of a and higher value of beta (slope and intercept in the Luedeking-Piret equation, respectively).

Candida↗
PubMed2003

[CaCO3 stimulates alpha-ketoglutarate accumulation during pyruvate fermentation by Torulopsis glabrata].

A large amount of alpha-ketoglutarate (alpha-KG) (6.8 g/L) was accumulated in flask culture when CaCO3 was used as a buffering agent in the production of pyruvate by multi-vitamin auxotrophic yeast Torulopsis glabrata CCTCC M202019. In a 5 L jar-fermentor, less alpha-KG (1.3 g/L) was produced when NaOH was used to adjust the pH, while more alpha-KG (11.5 g/L) detected when CaCO3 was used as the buffer. In the latter case, the molar carbon ratio of pyruvate to alpha-KG (C(PYR)/ CalphaKG) was similar to that obtained in flask culture, suggesting the accumulation of alpha-ketoglutarate was related to the addition of CaCO3. Furthermore, it was found that: (1) delaying the addition time of CaCO3 decreased the a-ketoglutarate formation but increased C(PYR)/ C(alphaKG); and (2) under vitamin limitation conditions increasing the concentration of CaCO3 led to an increased a-KG accumulation at the expenses of pyruvate. To study which ions in CaCO3 was responsible for the accumulation of alpha-KG, the effects of different pH buffers on the a-KG accumulation were studied. The level of alpha-KG was found to correlate with the levels of both Ca2+ and CO3(2-), with Ca2+ played a dominant role and CO3(2-) played a minor role. To find out which pathway was responsible for the accumulation of alpha-KG, the effects of biotin and thiamine on alpha-KG accumulation was investigated. The increase in biotin concentration led to an increase in alpha-KG accumulation and a decrease in C(PYR)/ C(alpha-KG), while the levels of alpha-KG and C(PYR)/C(alphaKG) were not affected by thiamine concentration. The activity of pyruvate carboxylase was increased as much as 40% when the medium was supplemented with Ca2+ . On the other hand, the activity of the pyruvate dehydrogenase complex was unaffected by the presence of Ca2+. To conclude, the higher level of a-KG was caused by higher activity of pyruvate carboxylase stimulated by Ca2+, with CO3(2-) served as the substrate of the reaction.

Biotechnology↗