Biomedical subjects

Guang-Ming Zeng

Publications and source records attributed to Guang-Ming Zeng.

At least 19 recordsLinked to original sources

PubMed2006

Fluorescence sensor for water in organic solvents prepared from covalent immobilization of 4-morpholinyl-1, 8-naphthalimide.

A new fluorescent dye, N-allyl-4-morpholinyl-1,8-naphthalimide (AMN), was synthesized as a fluorescence indicator in the fabrication of a sensor for determining water content in organic solvents. To prevent leakage of the fluorophore, AMN was photo-copolymerized with acrylamide, (2-hydroxyethyl)methacrylate, and triethylene glycol dimethacrylate on a glass surface treated with a silanizing agent. The sensing mechanism is based on the solvatochromic feature of the covalently immobilized AMN. The fluorescence intensity of AMN decreased with increasing water contents when it was excited at 400 nm. In the range of ca. 0.00-4.40% (v/v), the fluorescence intensity of AMN changed as a linear function of water content. The sensor exhibited satisfactory reproducibility, reversibility, and a response time (t (99)) of the order of 50 s. The detection limit was solvent-dependent, when acetonitrile was used as the solvent, and the detection limit could be as low as 0.006% (v/v) of water. Additionally, the prepared sensor is pH-insensitive and possesses a relatively long lifetime of at least one month.

Journal Article↗

PubMed2006

A hydroquinone biosensor using modified core-shell magnetic nanoparticles supported on carbon paste electrode.

A hydroquinone biosensor was developed and used to determine hydroquinone concentration in compost extracts based on the immobilization of laccase on the surface of modified magnetic core-shell (Fe(3)O(4)-SiO2) nanoparticles. Laccase was covalently immobilized on the magnetic nanoparticles by glutaraldehyde, which was modified with amino groups on its surface. The obtained magnetic bio-nanoparticles were attached to the surface of carbon paste electrode with the aid of a permanent magnet to determine hydroquinone. A good microenvironment for retaining the bioactivity of laccase was provided by the immobilization matrix. The linear range for hydroquinone determination was 1 x 10(-7) to 1.375 x 10(-4)M, with a detection limit of 1.5 x 10(-8)M. The current reached 95% of the steady-state current within about 60s. Hydroquinone concentration in compost extracts was determined by laccase biosensor and HPLC, the results of the two methods were approximately the same.

Biosensing Techniques↗

PubMed2006

Use of potassium dihydrogen phosphate and sawdust as adsorbents of ammoniacal nitrogen in aerobic composting process.

Three kinds of adsorbents-potassium dihydrogen phosphate, sawdust and mixture of potassium dihydrogen phosphate and sawdust were added respectively into composting to investigate their adsorption effect on ammonia. The experimental results showed that all the adsorbents could restrain ammonia volatilizing, with the sorption of potassium dihydrogen phosphate adsorbents being the best of all, the sorption of mixture adsorbent with potassium dihydrogen phosphate and sawdust being the second and the sorption of sawdust adsorbent being the last. Therefore, the total nitrogen loss ratios respectively reduced from 38% to 13%, 15% and 21% after adding these three kinds of adsorbents into composting. However, potassium dihydrogen phosphate produced negative influence on composting properties as its supplemented amount exceeded a quantity basis equivalent to 18% of total nitrogen in the composting, for example: pH value had been lessened, microorganism activity reduced, which finally resulted in the reduction of biodegradation ratio of organic matter. But it did not result in these problems when using the mixture of potassium dihydrogen phosphate and sawdust as adsorbent, in which the amount of potassium dihydrogen phosphate was under a quantity basis equivalent to 6% of total nitrogen in the composting. Moreover, the mixture adsorbent produced better adsorption effect on ammonia, and raised biodegradation ratio of organic matter from 26% to 33%.

Adsorption↗

PubMed2006

Effect of solids concentration on removal of heavy metals from mine tailings via bioleaching.

Mining of mineral ore and disposal of resulting waste tailings pose a significant risk to the surrounding environment. The objective of this work is to demonstrate the feasibility to remove heavy metals from mine tailings with the use of bioleaching and meanwhile to investigate the effect of solids concentration on removal of heavy metals from mine tailings by indigenous sulfur-oxidizing bacteria and the transformation of heavy metal forms after the bioleaching process. This work showed the laboratory results of bioleaching experiments on Pb-Zn-Cu mine tailings. The results showed that 98.08% Zn, 96.44% Cu, and 43.52% Pb could be removed from mine tailings by the bioleaching experiment after 13 days at 1% (w/v) solids concentration and the rates of pH reduction, ORP rise and sulfate production were reduced with the increase of solids concentration, due to the buffering capacity of mine tailing solids. The results also indicated that solid concentration 1% was found to be best to bacterial activity and metal solubilization of the five solids concentration tested (1%, 2%, 5%, 8% and 10%) under the chosen experimental conditions. In addition, the bioleaching had a significant impact on changes in partitioning of heavy metals.

Biodegradation, Environmental↗

PubMed2006

Application of a by-product of Lentinus edodes to the bioremediation of chromate contaminated water.

The agricultural by-product of Lentinus edodes was used as a novel biosorbent for bioremediation of chromate contaminated waste water in the simulated experimental conditions. The contact time, particle size, biosorbent dosage and optimum pH range were investigated to optimize the sorption condition. The biosorption by the biomass was strongly affected by pH. At pH 1.0-2.5, all hexavalent chromium was diminished, either removed by the biosorbent or reduced to less toxic trivalent chromium even in very high concentration of 1000 mg/L. The adsorbed hexavalent chromium and reduced trivalent chromium were both linearly dependent on the initial chromium concentration. Most uptake of Cr occurred at pH around 4. The maximum uptake of chromium was 21.5 mg/g when simulated with Langmuir model, which showed the potential biosorption capacity of this biomaterial. The change of oxidation-reduction potential (ORP) during biosorption process revealed strong reduction ability of this biosorbent. Comparing analysis from Fourier transform infrared spectrums indicated that nitrogen oxide and carboxyl groups were increased after biosorption. The energy-dispersive X-ray microanalyzer revealed the mechanism of cation exchange during biosorption.

Biodegradation, Environmental↗

PubMed2006

[Application of white-rot fungi in composting lead-contaminated waste].

Simulative lead polluted wastes which containing unpolluted soil, household waste, straw, bran and lead nitrate were prepared. Inoculation of white-rot fungi and uninoculation in composting of lead-contaminated waste were studied. Change of chemical factor, biological parameter and biological toxicity analyses with time during the composting process were determined to study effect of heavy metal on composting process and probability of application of white-rot fungi in composting of metal-contaminated waste. The results show the composting of lead-contaminated waste inoculated white-rot fungi could be successfully processed, which lead to the reduction of the bioavailability of Pb in compost and alleviate the potential harm from heavy metal. Under this composting process, for the final compost, pH, water-soluble organic carbon/nitrogen, volatile solid, lignin and coarse fibre remained reached 7.9, 4.01, 36.1%, 22.4g, 30.1g, respectively. In addition, 63.38% of Pb in residual fraction and 0% of Pb in soluble-exchangeable fraction were found in final compost, and the germination index of final compost reached 121%.

Biodegradation, Environmental↗

PubMed2006

[DNA extraction methods of compost for molecular ecology analysis].

Molecular ecology provides new techniques for studying compost microbes, and the DNA extraction is the basis of molecular techniques. Because of the contamination of humic acids, it turns to be more difficult for compost microbial DNA extraction. Three different approaches, named as lysozyme lysis, ultrasonic lysis and proteinase K lysis with CTAB, were used to extract the total DNA from compost. The detection performed on a nucleic acids and protein analyzer showed that all the three approaches produced high DNA yields. The agarose gel electrophoresis showed that the DNA fragments extracted from compost had a length of about 23 kb. A eubacterial 16S rRNA gene targeted primer pair (27F and 1 495R) was used for PCR amplification, and all the samples got almost the full length 16S rDNA sequence (about 1.5 kb). After digested by restriction endonucleases (Hae Ill and Alu I), the restriction map showed relatively identical microbial diversity in the DNA, which was extracted by the three different approaches. All the compost microbial DNA extracted by the three different approaches could be used for molecular ecological study, and researchers should choose the right approach for extracting microbial DNA from compost based on the facts.

Bacteria↗

PubMed2006

[Kinetic of pH control in anaerobic digestion of organic fraction of municipal solid waste in a batch reactor].

Using a material and ionization balance analysis of anaerobic digestion process, a kinetic model of pH control in a batch anaerobic digestion of organic fraction of municipal solid waste was established on the basis of substrate decay and microbial growth kinetics, and a corresponding computer soft ware was created. The optimal pH in different anaerobic digestion can be predicted by this model. Consequently the maximal methane production can be obtained in anaerobic system by controlling the pH in optimal value. Comparative experiments were conducted to validate the model. The experiments demonstrated that the methane production of anaerobic system under optimal pH was steadier than the same condition under uncontrolled pH, and the cumulative methane production had an average increment about 20%.

Bacteria, Anaerobic↗

PubMed2005

Bioremediation of Pb-contaminated soil by incubating with Phanerochaete chrysosporium and straw.

The bioremediation of the simulated lead (Pb)-contaminated soils by incubating with Phanerochaete chrysosporium and straw was studied at laboratory-scale. The soil pH, Pb concentration, soil microbial biomass, microbial metabolic quotient, microbial quotient and microbial biomass C-to-N ratios were monitored. The above indicators were to study the stress of Pb on soil and the microbial effects during the bioremediation process. It was found that the soils treated with P. chrysosporium and straw showed a much lower concentration of soluble-exchangeable Pb, lower metabolic quotient and biomass C-to-N ratios (0mgkg(-1) dry weight soil, 1.9mg CO(2)-Cmg(-1) biomass carbon and 4.9 on day 60, respectively) and higher microbial biomass and microbial quotient (2258mgkg(-1) dry weight soil and 7.86% on day 60, respectively) compared with the controls. In addition, the kinetic parameters in the model based on logistic equation were calculated by the BIOLOG data. By analyzing those kinetic parameters some information on the metabolic capacity of the microbial community could be obtained. All the results indicated that the bioavailability of Pb in contaminated soil was reduced so that the potential stress of Pb was alleviated, and also showed that the soil microbial effects and the metabolic capacity of microbial community were improved.

Color↗

PubMed2005

Fluorescence ratiometric pH sensor prepared from covalently immobilized porphyrin and benzothioxanthene.

A fluorescence ratiometric sensor for pH determination is described in this paper. The sensor incorporated the pH-sensitive dye meso-5,10,15,20-tetra-(4-allyloxyphenyl)porphyrin (TAPP) as an indicator and a pH-insensitive dye N-(2-methacryloxyethyl)benzo[k,l]thioxanthene-3,4-dicarboximide (MBTD), a benzothioxanthene derivative, as a reference for fluorescence ratiometric measurement. To prevent leakage of the dyes, both were photocopolymerized with acrylamide, hydroxyethyl methacrylate, and triethylene glycol dimethacrylate on the silanized glass surface. The reproducibility and response time of the prepared sensor were sufficient. Most common coexisting inorganic ions and organic compounds did not interfere with pH sensing. In the acidic pH range from 1.5 to 5.0 the fluorescence intensity ratio of the two dyes varied linearly as a function of pH. The sensing membrane was found to have a lifetime of at least one month. The sensor was applied to the analysis of waste water and artificial samples.

Acrylamide↗

PubMed2005

A ratiometric fluorescence sensor with broad dynamic range based on two pH-sensitive fluorophores.

This paper describes a novel ratiometric fluorescence sensor for pH measurement. Two pH-sensitive fluorophores, N-allyl-4-(4'-methyl-piperazinyl)-1,8-naphthalimide (AMPN) and meso-5,10,15,20-tetra-(4-allyloxyphenyl)porphyrin (TAPP), which served as referencing indicators for each other, were co-polymerized with acrylamide, hydroxyethyl methacrylate and triethylene glycol dimethacrylate on the silanized glass surface. The proposed sensor is based on the pH-dependent fluorescence intensities of the two fluorophores in different pH ranges. The sensor covers a broad dynamic range of pH 1.5-9.0. It exhibits satisfactory analytical performance in terms of selectivity, reproducibility and stability. The successful fabrication of the proposed sensor provides an alternative concept to utilizing two or more fluorophores for the development of ratiometric sensors covering a broad range of pH.

1-Naphthylamine↗

PubMed2005

Immunosensor for rapid detection of gibberellin acid in the rice grain.

A rapid, selective, sensitive, accurate, and inexpensive immunosensor for gibberellin acid detection was designed by coupling immunoassay with the square wave anodic stripping voltammetry (SWASV) technique involving copper ion labeled antigen in the competitive immunoreaction. The response signal expressed as the percentage of current reduction CR % (y) is linearly related to the concentration of GA (x) in the 1 microg/mL to approximately 150 microg/mL range with a regression equation of the form y = 0.44x + 15.59 and a correlation coefficient of 0.99. The results of the immunosensor assay were compared with those obtained by HPLC and ELISA, which show a satisfactory agreement. The immunosensor was used to determine the GA content in the hybrid rice grain samples taken in the growing period.

Antigens↗

PubMed2005

[Application of biosurfactant in composting of agricultural waste].

The biosurfactant of rhamonolipid (Rh) obtained from Pseudomonas aeruginosa was used in co-composting of rice straw and wheat bran, the efficiency of the promoter was studied under temperature control during the first stage of composting. Composting was done in an aerobic static bed of composting during which moisture content of mixture materials was controlled between 60% 70%, and the control of aeration adopted the timer by turns of 0.18m3/h for 20 minutes and pause for 40 minutes. Changes were studied including pH, organic matter, dissolved organic carbon (DOC), the biomass of microorganism, hemicellulase activity, carboxymethyl cellulose enzyme (CMCase) activity, hemi-cellulose and cellulose contents. The experimental results show that the degradation rate of organic matter is 13.4% higher than that of the control, and the average of DOC is improved by 2.2g/kg. The degradation contents of hemi-cellulose and cellulose are increased by 5.7%, 10.7% compared with the control. This indicate that the addition of Rh can improve microenvironment, strengthen polymers hydration, accelerate the co-composting process and improve the quality of composting production.

Biodegradation, Environmental↗

PubMed2004

Experimental study on Cr (V) reduction by Pseudomonas aeruginosa.

Investigation on Cr(V) reduction was conducted using Pseudomonas aeruginosa. The study demonstrated that the Cr(VI) can be effectively reduced to Cr(III) by Pseudomonas aeruginosa. The effects of the factors affecting Cr(VI) reduction rate including carbon source type, pH, initial Cr(VI) concentration and amount of cells inoculum were thoroughly studied. Malate was found to yield maximum biotransformation, followed by succinate and glucose, with the reduction rate of 60.86%, 43.76% and 28.86% respectively. The optimum pH for Cr(VI) reduction was 7.0, with reduction efficiency of 61.71% being achieved. With the increase of initial Cr(VI) concentration, the rate of Cr(VI) reduction decreased. The reduction was inhibited strongly when the initial Cr(VI) concentration increased to 157 mg/L. As the amount of cells inoculum increased, the rate of Cr(VI) reduction also increased. The mechanism of Cr(VI) reduction and final products were also analysed. The results suggested that the soluble enzymes appear to be responsible for Cr(VI) reduction by Pseudomonas aeruginosa, and the reduced Cr(III) was not precipitated in the form of Cr(OH)3.

Biotransformation↗

PubMed2004

[Effects of cadmium stress on active oxygen generation, lipid peroxidation and antioxidant enzyme activities in radish seedlings].

When seedlings of radish were treated with Cd2+ from 125 to 500 micromol/L, for a period of 12 to 96 h in hydroponic system, increase in ratio of SOD to CAT and levels of O(-.)(2), H(2)O(2), MDA indicate that Cd2+ induces oxidative stress in radish plants. Antioxidant enzyme activities responded differently to the level and time of Cd2+ treatment. Under 125 micromol/L Cd2+ treatment a gradual increase in SOD activity was observed; at 250, 500 micromol/L Cd2+ treatment SOD activity increased first, then declined considerably to even lower than that of the control during later Cd2+ treatment. A gradual decrease in roots and a marked increase in leaves in CAT activity were detected. GR activity in both leaves and roots were enhanced significantly with the increase in content of Cd2+ and time of treatment. The increase in GR activity suggests that AsA-GsH cycle may be activated to scavenge the AOS or the synthesis of PC may be stimulated to chelate cadmium.

Antioxidants↗

PubMed2004

Model-based evaluation on the conversion ratio of ammonium to nitrite in a nitritation process for ammonium-rich wastewater treatment.

Modeling for nitritation process was discussed and analyzed quantitatively for the factors that influence nitrite accumulation. The results indicated that pH, inorganic carbon source and Hydraulic Retention Time (HRT) as well as biomass concentration are the main factors that influenced the conversion ratio of ammonium to nitrite. A constant high pH can lead to a high nitritation rate and results in high conversion ratio on condition that free ammonia inhibition do not happen. In a CSTR system, without pH control, this conversion ratio can be monitored by pH variation in the reactor. The pH goes down far from the inlet level means a strongly nitrite accumulation. High concentration of alkalinity can promoted the conversion ratio by means of accelerating the nitritation rate through providing sufficient inorganic carbon source(carbon dioxide). When inorganic carbon source was depleted, the nitritation process stopped. HRT adjustment could be an efficient way to make the nitritation system run more flexible, which to some extent can meet the requirements of the fluctuant of inlet parameters such as ammonium concentration, pH, and temperature and so on. Biomass concentration is the key point, especially for a CSTR system in steady state, which was normally circumscribed by the characteristics of bacteria and may also affected by aeration mode and can be increased by prolonging the HRT on the condition of no nitrate accumulation when no recirculation available. The higher the biomass concentration is, the better the nitrite accumulation can be obtained.

Biomass↗

PubMed2003

Amperometric immunosensor based on polypyrrole/poly(m-pheylenediamine) multilayer on glassy carbon electrode for cytokinin N6-(Delta2-isopentenyl) adenosine assay.

A novel immunosensor based on a multilayer-coated glassy carbon electrode was designed to determine isopentenyl adenosine (iPA) in plants. The multilayer consists of polypyrrole and poly(m-phenylenediamine) with K4Fe(CN)6 and horseradish peroxidase (HRP) entrapped during electropolymerization. The ferrocyanide doped in polypyrrole functions as the mediator. The glucose oxidase bound on the immunosensor by the competitive immunoreaction involving iPA catalyzed the oxidation of the added glucose with the formation of H2O2, which is in turn reduced in the presence of HRP entrapped in poly(m-phenylenediamine). The current of the oxidized production of ferrocyanide reduced at -50 mV is inversely proportional to the concentration of iPA in the competitive immunoreaction. This immunosensor is able to be used about 40 times; after that its surface can be regenerated for a new immunosensor assembly by washing with 0.1M citrate-phosphate buffer (pH 4.6). The percentage of current response reduction (CR%) (y) is linearly related to the logarithm of the concentration of iPA (x) in the 5-300 microg/ml range, with a regression equation of the form y = 42.13x - 27.79 and a correlation coefficient of 0.9861. Five hybrid rice grain samples were analyzed with results in satisfactory agreement to those obtained by high-performance liquid chromatography.

Animals↗

PubMed2003

Amperometric biosensor with HRP immobilized on a sandwiched nano-Au / polymerized m-phenylenediamine film and ferrocene mediator.

An amperometric biosensor has been developed for the determination of H(2)O(2) in plant samples. Horseradish peroxidase (HRP) is immobilized on a sandwiched nano-Au particle / m-phenylenediamine polymer film by glutaraldehyde cross-linking. The film is formulated on the carbon paste electrode (CPE) blended with ferrocene as an electron transfer mediator. On the low concentration range, the current response is related to the H(2)O(2) concentration linearly from 0 to 8x10(-6) M with a detection limit of 1.3x10(-7) M. On a wider concentration range of 8x10(-6) to 1.4x10(-4) M, the reciprocal of current response is linearly related to the reciprocal of H(2)O(2) concentration. The apparent Michaelis-Menten constant (K(m)(app)) was calculated to be 0.0334 mM. The sensor has been tested by determining H(2)O(2) concentration in plant leaf samples.

Biosensing Techniques↗