1.Flow model of internal-loop granular sludge bed nitrifying reactor.
Chinese Journal of Biotechnology 2003;19(6):754-757
Internal-loop granular sludge bed nitrifying reactor is a new type of aerobic nitrifying equipment and has shown a good potential for nitrification. To study the flow pattern and construct the flow model, the tracer tests were performed using pulse stimulus-response technique. Based on the experimental results, the flow pattern in the settling section and the circulating section of reactor were analyzed by axial dispersion model and tank-in-series model, respectively. The dispersion number D/uL of 0.00148 in the settling section indicates that its flow pattern is similar to plug flow reactor (PFR), and the series number N of 1.021 in the circulating section indicates that its flow pattern is similar to continuously stirred tank reactor (CSTR). During steady state, the theoretic hydraulic retention time is 360 min, and the actual hydraulic retention time is 341.2 min. The percentage of dead space in the reactor is 5.22%, thereinto the dead space caused by biomass (db ) is 0.75 % and the hydraulic dead space (dh) is 4.47%, which shows that the structural performance of the reactor is excellent. Based on the experiments and analysis, a model of CSTR and PFR in series was constructed. The actual hydraulic retention time distribution of the reactor is in good agreement with the model predictions. Since the relative error between them is 8.56%, the model is accurate to describe the flow pattern. The results have laid a foundation for the kinetic model of the reactor and will be helpful for its design and operation.
Bioreactors
;
Kinetics
;
Models, Theoretical
;
Nitrites
;
metabolism
;
Sewage
2.Homeostatic medicine: new strategy and concept of health maintenance as well as diagnosis and treatment of diseases.
Li Zheng QIN ; Jian ZHOU ; Lei HU ; Song Ling WANG
Chinese Journal of Stomatology 2023;58(2):109-117
Homeostasis is a dynamic balance process of self-regulating. Biological systems remain stable through adapting to changing external conditions to maintain normal life activities. Homeostatic medicine is the science of studying homeostasis of human molecules, cells, organs and the whole body. It is a comprehensive discipline based on maintaining homeostasis to keep human health and assist for diseases prevention and diagnoses. Homeostatic medicine focuses on the whole body and on the role of homeostasis in health and disease, which is expected to provide new ideas and strategies for maintaining health as well as diagnosing and treating diseases. Nitric oxide (NO) plays an important role in the control of multisystem homeostasis. Nitrate is an important substance in regulating NO homeostasis through the nitrate-nitrite-NO pathway. Sialin, nitrate transporter which is located in the cell membrane and cytoplasm, mediates multiple cellular biological functions. The nitrate-nitrite-NO pathway and sialin-mediated biological functions play an important role in the regulation of body homeostasis.
Humans
;
Nitrates/metabolism*
;
Nitrites/metabolism*
;
Homeostasis
;
Nitric Oxide
3.Changes of NO2-/NO3- and nitration tyrosine concentrations in induced sputum of silicosis patients.
Kun WANG ; Rui WANG ; Zheng-liang LIU ; Jin-long MEN ; En-guang WAN ; Ling-min KONG ; Jin-peng WANG ; Chao SHEN ; Yang LI
Chinese Journal of Industrial Hygiene and Occupational Diseases 2009;27(1):30-33
OBJECTIVETo analyze the change in nitration tyrosine, NO(2)(-)/NO(3)(-)level in induced sputum of silicosis patients and dust exposure workers and to evaluate the approach and feasibility of nitric oxide (NO) metabolites as early detection indicators of silicosis.
METHODSNitration tyrosine, NO(2)(-)/NO(3)(-)concentration in induced sputum of 80 dust exposure workers, 84 silicosis patients, 30 logistic personnel with no history of exposure to silica dust were determined and the relationship among Nitration tyrosine, NO(2)(-)/NO(3)(-)level and dust exposure years as well as pulmonary function tests were analyzed.
RESULTSNO(2)(-)/NO(3)(-)level among exposed group [60.30 (46.58) micromol/l] was significantly higher than the control group [36.90 (22.28) micromol/l], (P < 0.05), and the level of NO(2)(-)/NO(3)(-)among the cases [79.65 (89.10) micromol/l] was significantly higher than exposed group as well as the control group (P < 0.05). Compared with control, the level of nitration tyrosine in exposed group [3.51 (0.46) nmol/l] and the cases [3.48 (0.49) nmol/l] was significantly higher (P < 0.05). NO(2)(-)/NO(3)(-)level and dust exposure years were positively correlated (r = 0.3733 and 0.3830 respectively P < 0.05); NO(2)(-)/NO(3)(-)level and pulmonary function tests (FVC%, FEV1.0%, PEF%, MEF25%, MEF50%) were negatively correlated (r = 0.1540, 0.1723, 0.1535, 0.1485, 0.1643 respectively, P < 0.05). There was no correlation between nitration tyrosine and dust exposure years (P > 0.05), no correlation between nitration tyrosine and pulmonary function test (P > 0.05).
CONCLUSIONThe level of NO(2)(-)/NO(3)(-)level in induced sputum has a positive correlation with exposure to dust, suggesting that there will be a certain feasibility of the NO(2)(-)/NO(3)(-)as indicators of early detection of silicosis.
Adult ; Humans ; Middle Aged ; Nitrates ; metabolism ; Nitrites ; metabolism ; Silicosis ; metabolism ; Sputum ; metabolism ; Tyrosine ; metabolism
4.Performance of internal-loop air-lift nitrifying bioreactor.
Feng-Mei LIN ; Ping ZHENG ; Yang-Yang ZHAO ; Bao-Lan HU ; Jian-Song CHEN
Chinese Journal of Biotechnology 2002;18(4):492-496
The performance of internal-loop air-lift nitrifying bioreactor was good with strong tolerance to influent ammonia concentration (78.49 mmol/L), high volume converting rate (163.18 mmol/L.d) and obvious working stability (ammonia removal > 94.42%). During operation of internal-loop air-lift bioreactor, the nitrifying activated sludge was granulated. The nitrifying granular activated sludge began to appear on day 45. Its average diameter was 0.83 mm, settling velocity was 55.53 m/h and specific ammonia removal rate was 0.95 mmol (NH4(+)-N)/g (VS).d. The nitrifying granular activated sludge had the activity for anaerobic ammonia oxidation with ammonia oxidation rate of 0.23 mmol (NH4(+)-N)/g(VS).d and nitrite reduction rate of 0.24 mmol (NO2(-)-N)/g(VS).d.
Ammonia
;
metabolism
;
Anaerobiosis
;
Bioreactors
;
Nitrites
;
metabolism
;
Nitrogen
;
metabolism
;
Oxidation-Reduction
;
Sewage
;
analysis
5.Enrichment regulation of anammox bacteria in the anammox start-up process.
Chongjun CHEN ; Weijing ZHU ; Xiaoxiao HUANG ; Weixiang WU
Chinese Journal of Biotechnology 2014;30(6):891-900
To study the enrichment regulation of anammox bacteria during the whole start-up process of anammox reaction, two reactors with addition of carries of Spherical Plastic (SP) and Bamboo Charcoal (BC) and one without carrier (CK) were used to start anammox reaction. Then FISH and q-PCR analyses for the growth of all anammox bacteria were conducted during the operational process. The results indicate that the number of anammox bacteria in all reactors increased with time during the whole start-up process, which was consistent with the removal rate of ammonium and nitrite. On day 123 of stable phase, the percent of anammox cells in the sludge of CK, SP and BC accounted for 23.3%, 32.6% and 43.7%, respectively. The number of anammox bacteria 16S rRNA gene copies was (25.64 +/- 2.76) x 10(7), (47.12 +/- 2.76) x 10(7) and (577.99 +/- 27.25) x 10(7) copies g(-1) VSS in the sludge of CK, SP and BC, respectively. Carrier addition could dramatically increase enrichment of anammox bacteria. BC addition significantly increased the anammox bacteria number in the UASB reactor which resulted in the acceleration of the anammox start-up process. In addition, the max specific growth rate and the minimum doubling time were 0.064 d(-1) and 10.8 d in BC reactor. The max specific growth rate of anammox bacteria in BC reactor was 1.78 times and 1.88 times greater than that in CK and SP reactor, respectively. Therefore, the FISH and q-PCR analyses were suitable for determining the enrichment regulation of anammox bacteria during the start-up time, while a bit of differences in results existed between the two analytical methods due to the difference in analysis targets.
Ammonia
;
metabolism
;
Bacteria
;
growth & development
;
metabolism
;
Bioreactors
;
Industrial Microbiology
;
Nitrites
;
metabolism
;
Oxidation-Reduction
;
Sewage
;
microbiology
6.Research on critical aerating flux of internal-loop granular sludge bed nitrifying reactor.
Gang LU ; Ping ZHENG ; Feng-Yi XIA
Chinese Journal of Biotechnology 2004;20(5):795-799
The internal-loop granular sludge bed nitrifying reactor is a new type of aerobic nitrifying equipment and has taken on a good potential for nitrification. The critical aerating flux for liquid loop and critical aerating flux for fluidization of granular sludge are two important parameters for its operation. The relationship between liquid superficial velocity in riser (U1r) and aerating flux(Ugr) was studied, the model parameters were measured by experiment, and the relational expression was established. According to the model, the critical aerating flux for liquid loop and the critical aerating flux for fluidization of granular sludge were calculated as 1.017cm/min and 2.662cm/min, respectively. The experimental data from reactor operation showed that the two calculated critical aerating fluxes near the practical values. So they could be used to direct the design and operating optimization for the internal-loop granular sludge bed nitrifying reactor.
Bacteria, Aerobic
;
metabolism
;
Bioreactors
;
Nitrites
;
metabolism
;
Sewage
;
chemistry
;
microbiology
;
Waste Disposal, Fluid
;
methods
7.Anaerobic ammonium oxidation for treatment of ammonium-rich wastewaters.
Lei ZHANG ; Ping ZHENG ; Chong-jian TANG ; Ren-cun JIN
Journal of Zhejiang University. Science. B 2008;9(5):416-426
The concept of anaerobic ammonium oxidation (ANAMMOX) is presently of great interest. The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile, the ANAMMOX is equally valuable in treatment of ammonium-rich wastewaters. Related processes including partial nitritation-ANAMMOX and completely autotrophic nitrogen removal over nitrite (CANON) have been developed, and lab-scale experiments proved that both processes were quite feasible in engineering with appropriate control. Successful full-scale practice in the Netherlands will accelerate application of the process in future. This review introduces the microbiology and more focuses on application of the ANAMMOX process.
Bacteria, Anaerobic
;
metabolism
;
Bioreactors
;
Nitrites
;
metabolism
;
Nitrogen
;
metabolism
;
Oxidation-Reduction
;
Quaternary Ammonium Compounds
;
metabolism
;
Waste Disposal, Fluid
;
Water Purification
;
methods
8.Tyrosine nitration site specificity identified by LC/MS in nitrite-modified collagen type IV.
Zhen WANG ; David C PAIK ; James P DILLON ; Elizabeth R GAILLARD
Experimental & Molecular Medicine 2007;39(1):74-83
Non-enzymatic nitrite induced collagen cross-linking results in changes reminiscent of age-related damage and parallels the well-known model system, non-enzymatic glycation. We have recently observed that nitrite modification of basement membrane proteins can induce deleterious effects on overlying retinal pigment epithelial cells in studies relevant to age-related macular degeneration. The present work was undertaken in order to confirm 3-nitro-tyrosine (3-NT) as a product of the reaction and to identify the site specificity of nitration in collagen IV, a major component of basement membranes. Human collagen type IV was modified via incubation with 200 mM NaNO2 (pH=7.38) for one week at 37degrees C. The modified protein was prepared in 2 different ways, including acid hydrolysis and trypsin digestion for site specificity determination. The samples were analyzed by LC/MS using a C12 RP column. Site specificity was determined from tandem MS/MS data utilizing TurboSEQUEST software and the Swiss-Prot sequence database. 3-NT was detected in protein digests and acid hydrolysates of nitrite modified collagen IV. Positive identification with standard 3-NT was confirmed by identical Rt, lambda(max)=279 nm and 355 nm, and m/z=227. Analyses of tryptic digests identified four sites of tyrosine nitration, alpha1(IV)Y348, alpha1(IV)Y534, alpha2(IV)Y327, and alpha2(IV)Y1081. These sites are located in the triple-helical region of the protein and provide clues regarding potential sites for nitrite modification in collagen type IV.
Tyrosine/*metabolism
;
Tandem Mass Spectrometry
;
Substrate Specificity
;
Nitrites/*metabolism
;
Humans
;
Collagen Type IV/*metabolism
;
Chromatography, Liquid
;
Binding Sites
9.Altered renal expression of nitric oxide synthase isozymes in spontaneously hypertensive rats.
Soo Wan KIM ; Kyung Hyub MOON ; Seong Cheol LEE ; Nam Ho KIM ; Dae Gil KANG ; Jong Un LEE ; Ki Chul CHOI ; Young Joon KANG
The Korean Journal of Internal Medicine 1999;14(1):21-26
OBJECTIVES: The present study was aimed at exploring whether the pathogenesis of hypertension is related with an altered expression of nitric oxide synthase (NOS) isozymes, i.e., bNOS, iNOS and ecNOS. METHOD: By Western blot analysis, the expression of NOS isozymes were determined in the kidney isolated from spontaneously hypertensive rats (SHR) and their normotensive control, Wistar-Kyoto rats (WKY). The NOx (nitrite/nitrate) contents were also determined in the kidney and plasma. RESULTS: The plasma NOx was significantly increased in SHR compared with that in WKY. The basal level of NOx was higher in the medulla and cortex of the kidney in SHR compared with that in WKY rat. bNOS proteins were expressed higher in the outer medulla and cortex, and iNOS proteins were higher in the inner medulla, outer medulla and cortex in SHR. ecNOS expression did not significantly differ between the SHR and WKY. CONCLUSIONS: These results indicate that the NO generation may not be impaired, but rather increased. It is likely that the increased expression of NOS isozymes is a counter-reactive phenomenon secondary to the increased blood pressure in this model of hypertension.
Animal
;
Hypertension/physiopathology
;
Hypertension/enzymology*
;
Isoenzymes/metabolism
;
Kidney/enzymology*
;
Male
;
Nitrates/metabolism
;
Nitrates/blood
;
Nitric Oxide/biosynthesis
;
Nitric-Oxide Synthase/metabolism*
;
Nitrites/metabolism
;
Nitrites/blood
;
Rats
;
Rats, Inbred SHR
;
Rats, Inbred WKY
10.Effect of osmotic pressure on nitrification.
Chinese Journal of Biotechnology 2006;22(1):156-161
The effect of osmotic pressure on nitrification was investigated in the internal-loop air-lift nitrifying reactor. When influent ammonia concentration is kept at 420mg x L(-1) and influent osmotic pressure is increased from 4.3 to 18.8 x 10(5) Pa, the ammonia conversion of the nitrifying bioreactor is maintained between 93% and 100%. After influent osmotic pressure is further increased to 19.2 x 10(5)Pa, the ammonia conversion goes down to 69.2%. The influence of osmotic pressure on nitrification takes place without any alarm and the critical osmotic pressure is between 18.8 x 10(5) and 19.2 x 10(5) Pa. During osmotic stress, the nitrifying bacterial populations in the activated sludge become simplified, the cell size becomes smaller, the inner membrane becomes less and some unknown inclusion particles are formed. The cell structure is restored as soon as the osmotic pressure is removed. Addition of potassium is able to relieve the effect of osmotic pressure on nitrification. The nitrifying activity of the activated sludge is stimulated by the osmotic stress, and the specific ammonia conversion is increased from 0.083 kg x kg(-1) x d(-1) to 0.509 kg x kg(-1) x d(-1) and 2.569 kg x kg(-1) x d(-1), respectively.
Bioreactors
;
microbiology
;
Nitrates
;
metabolism
;
Nitrites
;
metabolism
;
Nitrobacter
;
metabolism
;
Osmotic Pressure
;
Quaternary Ammonium Compounds
;
metabolism
;
Waste Disposal, Fluid
;
methods
;
Water Pollutants, Chemical
;
metabolism