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1.
Cell Transplant ; 31: 9636897221081487, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35225026

RESUMO

Severe lumbosacral pain, paraparesis or paraplegia, and urinary incontinence are common but frustrating problems in dogs with lumbosacral spinal cord injury (SCI). The surgical interventions including stabilization and decompression may not restore satisfying neurological functions in severe SCI. Adipose tissue-derived mesenchymal stem cells (Ad-MSCs) show benefits in immunomodulation, anti-inflammation, and promotion of axonal growth and remyelination, and also display efficacy in several diseases in veterinary medicine. In this report, four dogs presented with fracture of sacrum vertebrae or fracture of seventh lumbar and lumbosacral displacement after road traffic accidents. The clinical signs include lumbosacral pain (4/4), paraparesis (3/4), paraplegia (1/4), and urinary incontinence (4/4). All dogs were treated by surgical decompression with or without stabilization 1 to 7 weeks after trauma. Allogeneic canine Ad-MSCs (cAd-MSCs) were injected locally on nerve roots through the surgical region in all dogs. One dose of intravenous transplantation and 4 doses of local transplantation were also performed within 8 weeks after the surgery separately. All dogs showed significant neurological improvements with normal ambulatory ability (4/4) and urinary control (3/4) 3 months after the surgery and the first cAd-MSCs transplantation. No side effect was related to multiple cAd-MSCs transplantations during 6 months monitoring in all dogs. In conclusion, multiple cAd-MSCs transplantations could be a recommended treatment combined with surgery in dogs with lumbosacral SCI.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais , Traumatismos da Medula Espinal , Animais , Cães , Medula Espinal/cirurgia , Traumatismos da Medula Espinal/cirurgia , Traumatismos da Medula Espinal/veterinária
2.
BMC Musculoskelet Disord ; 17: 114, 2016 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-26936194

RESUMO

BACKGROUND: Health-related quality of life (HRQoL) has been used to assess subjects' prognosis and recovery following hip fracture. However, evidence is mixed regarding the effectiveness of interventions to improve HRQoL of elders with hip fracture. The purposes of this study were to identify distinct HRQoL trajectories and to evaluate the effects of two care models on these trajectories over 12 months following hip-fracture surgery. METHODS: For this secondary analysis, data came from a randomized controlled trial of subjects with hip fracture receiving three treatment care models: interdisciplinary care (n = 97), comprehensive care (n = 91), and usual care (n = 93). Interdisciplinary care consisted of geriatric consultation, discharge planning, and 4 months of in-home rehabilitation. Comprehensive care consisted of interdisciplinary care plus management of malnutrition and depressive symptoms, fall prevention, and 12 months of in-home rehabilitation. Usual care included only in-hospital rehabilitation and occasional discharge planning, without geriatric consultation and in-home rehabilitation. Mental and physical HRQoL were measured at 1, 3, 6, and 12 months after discharge by the physical component summary scale (PCS) and mental component summary scale (MCS), respectively, of the Medical Outcomes Study Short Form 36, Taiwan version. Latent class growth modeling was used to identify PCS and MCS trajectories and to evaluate how they were affected by the interdisciplinary and comprehensive care models. RESULTS: We identified three quadratic PCS trajectories: poor PCS (n = 103, 36.6 %), moderate PCS (n = 96, 34.2 %), and good PCS (n = 82, 29.2 %). In contrast, we found three linear MCS trajectories: poor MCS (n = 39, 13.9 %), moderate MCS (n = 84, 29.9 %), and good MCS (n = 158, 56.2 %). Subjects in the comprehensive care and interdisciplinary care groups were more likely to experience a good PCS trajectory (b = 0.99, odds ratio [OR] = 2.69, confidence interval [CI] = 7.24-1.00, p = 0.049, and b = 1.32, OR = 3.75, CI = 10.53-1.33, p = 0.012, respectively) than those who received usual care. However, neither care model improved MCS. CONCLUSIONS: The interdisciplinary and comprehensive care models improved recovery from hip fracture by increasing subjects' odds for following a trajectory of good physical functioning after hospitalization. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT01350557 ).


Assuntos
Prestação Integrada de Cuidados de Saúde , Fraturas do Quadril/terapia , Qualidade de Vida , Idoso , Idoso de 80 Anos ou mais , Teorema de Bayes , Terapia Combinada , Feminino , Fraturas do Quadril/diagnóstico , Fraturas do Quadril/fisiopatologia , Fraturas do Quadril/psicologia , Humanos , Modelos Lineares , Masculino , Dinâmica não Linear , Razão de Chances , Equipe de Assistência ao Paciente , Estudos Prospectivos , Recuperação de Função Fisiológica , Fatores de Risco , Inquéritos e Questionários , Taiwan , Fatores de Tempo , Resultado do Tratamento
3.
Ying Yong Sheng Tai Xue Bao ; 25(8): 2385-9, 2014 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-25509093

RESUMO

To explore the alleviation effect of silicon on wheat growth under copper stress, cultivar Aikang 58 was chosen as the experimental material. The growth, root activities and root tip ultrastructures of wheat seedlings, which were cultured in Hoagland nutrient solution with five different treatments (control, 15 mg x L(-1) Cu2+, 30 mg x L(-1) Cu2+, 15 mg x L(-1) Cu2+ and 50 mg x L(-1) silicon, 30 mg x L(-1) Cu2+ and 50 mg x L(-1) silicon), were fully analyzed. The results showed that root length, plant height and root activities of wheat seedlings were significantly restrained under the copper treatments compared with the control (P < 0.01), while these restraining effects were alleviated after adding silicon to copper-stress Hoagland nutrient solution. Under copper stress, the cell wall and cell membrane of wheat seedling root tips suffered to varying degrees of destruction, which caused the increase of intercellular space and the disappearance of some organelles. After adding silicon, the cell structure was maintained intact, although some cells and organelles were still slightly deformed compared with the control. In conclusion, exogenous silicon could alleviate the copper stress damages on wheat seedlings and cellular components to some extent.


Assuntos
Membrana Celular/ultraestrutura , Parede Celular/ultraestrutura , Cobre/química , Silício/química , Triticum/citologia , Raízes de Plantas/citologia , Plântula/citologia
4.
Nurs Midwifery Stud ; 3(1): e13962, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25414891

RESUMO

BACKGROUND: Long-term care residents are susceptible to constipation and one-half to three quarter of older nursing home residents receive laxatives regularly. OBJECTIVES: The purpose of this study was to evaluate the factors related to abnormal bowel function and explore the effectiveness of laxative treatment among the elderly residents of a nursing home. PATIENTS AND METHODS: A total of 110 residents older than 65 years old was enrolled in this study. The following variables were gathered: age, gender, body mass index (BMI), length of stay, daily fluid intake, type of food, functional level, cognitive ability, physical therapy status, somatic and psychiatric diseases, number of medications, and medication use. The use and dosage of laxatives were recorded by means of Anatomical Therapeutic Chemical (ATC) classification system. Normal bowel function was defined as defecation frequency from three defecations per day to three defecations per week and stool consistency score of three to five on Bristol Stool Form Scale. A comparison between groups with normal and abnormal bowel function was drawn. RESULTS: Low BMI, increased fluid intake, liquid food intake, poor functional level, poor cognition, and a history of stroke were significantly associated with altered bowel function (P < 0.05). The most frequently used laxatives were glycerol, senna glycoside, and magnesium oxide. There were significant differences in laxative regimens between residents with normal and altered bowel function; those with altered bowel function tended to take more laxatives than those with normal bowel function. CONCLUSIONS: This study suggested that treatment of constipation in the nursing home was unsatisfactory. To improve treatment outcomes in those susceptible to altered bowel function, a coordinated approach with involvement of physicians, nursing staff, and other professionals including dieticians and pharmacists seems necessary.

5.
Water Sci Technol ; 70(3): 548-54, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25098887

RESUMO

In this study, gelation-facilitated biofilm formation as a new mechanism is proposed for the phenomenon of aerobic granulation in biological wastewater treatment. To obtain an experimental proof for the gelation-based theory, the granulation process was simulated in a chemical system using latex particles for bacterial cells and organic polymers (alginate and peptone) for extracellular polymeric substances (EPS) in a solution with the addition of cations (Ca²âº, Mg²âº and Fe³âº). The results showed that at a low alginate content (70 mg g⁻¹ mixed liquid suspended solids (MLSS)) flocculation was observed in the suspension with loose flocs. At a higher alginate content (180 mg g⁻¹ MLSS), together with discharge of small flocs, formation of artificial gel granules was successfully achieved leading to granulation. The artificial granules show a morphological property similar to that of actual microbial granules. However, if the protein content increased, granulation became difficult with little gel formation. The experimental work demonstrates the importance of the bonding interactions between EPS functional groups and cations in gel formation and granulation. The laboratory results on the formation of artificial granules provide a sound proof for the theory of gelation-facilitated biofilm formation as the main mechanism for aerobic granulation in sludge suspensions.


Assuntos
Aerobiose , Biofilmes , Géis , Águas Residuárias , Floculação
6.
Huan Jing Ke Xue ; 35(5): 1850-6, 2014 May.
Artigo em Chinês | MEDLINE | ID: mdl-25055677

RESUMO

Microbial granules were successfully developed in a pilot-scale sequencing batch reactor (SBR) for the treatment of real municipal wastewater. The aerobic granules developed had good settleability with a settling velocity of > 21 mh-1. The mature granular sludge was capable of simultaneous removal of chemical oxygen demand (COD), nitrogen (N) and phosphorus (P). With the cycle of 3 h, the effluent COD, ammonium nitrogen (NH+4 -N) and total nitrogen (TN) concentrations were <50 mg L-1, <5. 0 mg L-1, and <15 mgL-1, respectively. The removal efficiency for TN and total phosphorus (TP) was about 50%. Examinations by confocallaser scanning microscopy (CLSM) showed that extracellular polymeric substances (EPS) were uniformly distributed throughout the granules, forming the granule structure matrix. X-ray diffraction (XRD) analysis indicated the presence of SiO2 and other metal oxides inside aerobic granules, implying that minerals in real wastewater might function as the seed in the initial stage of aerobic granulation.


Assuntos
Reatores Biológicos , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Análise da Demanda Biológica de Oxigênio , Nitrogênio/química , Fósforo/química , Esgotos/química , Dióxido de Silício/química , Difração de Raios X
7.
Huan Jing Ke Xue ; 34(5): 1828-34, 2013 May.
Artigo em Chinês | MEDLINE | ID: mdl-23914535

RESUMO

For the treatment of municipal wastewater, the effects of the reversed A2/O-MBR system on COD, NH4+ -N, TN, TP, SS and transmembrane pressure (TMP) were investigated through two-point feeding. The results indicated that the removal efficiencies for COD and NH4+ -N were high in the system, the effluent met the requirements of the Class A in first grade discharge standard of GB 18918-2002. The effluent TN was < 15 mg x L(-1) when the reflux ratio of nitrification was 200%, whereas the average TP removal rate was 90% after the excessive sludge was removed. The effluent SS was < 10 mg x L(-1) before the large-scale breakage of membrane. The TMP increased gradually with the operation of the system, if the way of aeration was not correct, the TMP would increase quickly. Efficient separation by the membrane contributed to the removal of COD, TP and SS. Because there was no sludge washout in the system, SRT could be properly controlled, it was good for the ammonia-oxidizing bacteria and denitrifying bacteria which both have long life-cycle. Even if the inflow was increased to 1.5 fold, the effluent quality was good when the sludge concentration was increased to 6500 mg x L(-1).


Assuntos
Reatores Biológicos , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Reatores Biológicos/microbiologia , Cidades , Filtração/métodos , Membranas Artificiais , Purificação da Água/métodos
8.
Br J Nutr ; 104(1): 93-9, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20193094

RESUMO

Nutrition is a key element in geriatric health, and nutritional screening/assessment is a key component of comprehensive geriatric evaluation. The study aimed to validate the Mini Nutritional Assessment Taiwan version-1 (MNA-T1) which adopted population-specific anthropometric cut-points, and version-2 (MNA-T2) which replaced BMI with mid-arm and calf circumferences in the scale for predicting the nutritional status of elderly Taiwanese. Using data of a population-representative longitudinal study of 2802 Taiwanese aged 65 years or older, the study graded the nutritional status of each subject with the original and both modified versions at baseline, analysed their hospital length of stay, the Activities of Daily Living (ADL), the Center for Epidemiologic Studies Depression Scale (CES-D) and life-satisfaction scores at baseline and end of 4 years, and tracked their survival during the period. Results showed that both modified versions had superior predictive abilities compared with the original MNA, and their graded scores correlated better with hospital length of stay, and ADL, CES-D and life-satisfaction scores. Both modified versions were effective in predicting follow-up mortality risk. The relative mortality risk was about 7 times for those rated malnourished and 2.5 times for those rated at risk of malnutrition compared with those who were rated normal at baseline by the two modified versions. These results suggest that both of the modified versions are effective in predicting the nutrition and health statuses of Taiwanese elderly and would serve to validate the predictive ability of the two modified versions. The MNA-T2, which requires no BMI, can make routine nutritional screening/assessment an easier task.


Assuntos
Índice de Massa Corporal , Avaliação Geriátrica , Mortalidade , Avaliação Nutricional , Estado Nutricional , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Braço , Depressão , Feminino , Hospitalização , Humanos , Perna (Membro) , Estudos Longitudinais , Masculino , Prognóstico , Modelos de Riscos Proporcionais , Valores de Referência , Fatores de Risco , Análise de Sobrevida , Taiwan
9.
Water Res ; 42(13): 3552-60, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18541284

RESUMO

Laboratory experiments were carried out to investigate the evolution of the bacterial community during aerobic sludge granulation. The experiments were conducted in three 2.4L sequencing batch reactors (SBRs) that were seeded with activated sludge and fed with glucose-based synthetic wastewater. Three different influent organic concentrations were introduced into the three SBRs, R1, R2 and R3, resulting in chemical oxygen demand (COD) loading rates of 1.5 (R1), 3.0 (R2) and 4.5 (R3)kg/m(3)d, respectively. Changes in bacterial diversity throughout the granulation process were monitored and analysed using polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) techniques. The experimental results demonstrate that glucose-fed aerobic granules could be formed without significant presence of filamentous bacteria. Granules formed at different loading rates had different morphology, structural properties and bacterial species. A higher loading rate resulted in faster formation of larger and loose granules, while a lower loading rate resulted in slower formation of smaller and more tightly packed granules. The biomass underwent a dynamic transformation in terms of bacterial species richness and dominance during the granulation process. The reactor with the highest substrate loading rate had the lowest species diversity, while the reactor with the lowest substrate loading rate had the highest species diversity. Different dominant species of beta- and gamma-Proteobacteria and Flavobacterium within the granule communities from the three different SBRs were confirmed by analysis of 16S rDNA sequences of the PCR products separated by DGGE. It is apparent that a few common bacterial species play an important role in the formation and growth of aerobic granules and help sustain the granular sludge structure in the bioreactors.


Assuntos
Esgotos/microbiologia , Aerobiose , Microscopia Eletrônica de Varredura
10.
Appl Microbiol Biotechnol ; 67(4): 484-8, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15647939

RESUMO

In the aerobic granular sludge reactor, the substrate loading is related to the size of the aerobic granules cultivated. This study investigated the influence of substrate surface loading on the growth and substrate-utilization kinetics of aerobic granules. Results showed that microbial surface growth rate and surface biodegradation rate are fairly related to the substrate surface loading by the Monod-type equation. In this study, both the theoretical maximum growth yield and the Pirt maintenance coefficient were determined. It was found that the estimated theoretical maximum growth yield of aerobic granules was as low as 0.2 g biomass g(-1) chemical oxygen demand (COD) and 10-40% of input substrate-COD was consumed through the maintenance metabolism, while experimental results further showed that the unit oxygen uptake by aerobic granules was 0.68 g oxygen g(-1) COD, which was much higher than that reported in activated sludge processes. Based on the growth yield and unit oxygen uptake determined, an oxidative assimilation equation of acetate-fed aerobic granules was derived; and this was confirmed by respirometric tests. In aerobic granular culture, about 74% of the input substrate-carbon was converted to carbon dioxide. The growth yield of aerobic granules was three times lower than that of activated sludge. It is likely that high carbon dioxide production is the main cause of the low growth yield of aerobic granules, indicating a possible energy uncoupling in aerobic granular culture.


Assuntos
Bactérias Aeróbias/crescimento & desenvolvimento , Bactérias Aeróbias/metabolismo , Esgotos/microbiologia , Acetatos/metabolismo , Biomassa , Reatores Biológicos , Biotecnologia/métodos , Meios de Cultura , Cinética , Oxigênio/metabolismo , Especificidade por Substrato , Propriedades de Superfície
11.
Curr Microbiol ; 49(1): 42-6, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15297929

RESUMO

Aerobic granules were successfully developed at substrate N/COD ratios ranging from 5/100 to 30/100 by weight. By measuring respective respirometric activities of heterotrophic, ammonia-oxidizing, and nitrite-oxidizing bacteria, it was found that the relative abundance of nitrifying bacteria over heterotrophs in aerobic granules was closely related to the substrate N/COD ratios. Results further showed that the populations of both ammonia and nitrite oxidizers were significantly enriched with the increase of the substrate N/COD ratio, while a decreasing trend of heterotrophic population was observed in the aerobic granules. These seem to indicate that high substrate N/COD ratio favors the selection of nitrifying bacteria in the aerobic granules, while the relative activity of nitrifying population against heterotrophic population evolved until a balance between two populations was reached in the aerobic granular sludge community. Moreover, cell elemental composition was correlated with the shift in microbial populations, e.g., the enriched nitrifying population in the aerobic granules resulted in a high cell nitrogen content normalized to cell carbon content. This study provides a good insight into microbial interaction in aerobic granules.


Assuntos
Aerobiose/fisiologia , Bactérias Aeróbias/metabolismo , Reatores Biológicos/microbiologia , Compostos de Nitrogênio/metabolismo , Consumo de Oxigênio/fisiologia , Bactérias Aeróbias/isolamento & purificação , Bactérias Aeróbias/fisiologia , Biotecnologia
12.
Artigo em Chinês | MEDLINE | ID: mdl-15281454

RESUMO

OBJECTIVE: To establish a sensitive and specific method EITB for the immunodiagnosis of cysticercosis. METHODS: Two-dimensional electrophoresis was used to analyze and purify the cyst fluid antigen. Western blotting using the sera of patients with cysticercosis, hydatidosis, and other heteroserum was used to screen the specific antigens. EITB using the specific antigen was established and compared with ELISA. The detection effect of serum and blood on filter paper in EITB was also compared. RESULTS: Two specific antigens with isoelectric point (pI) of 9.4 and Mr of 14000 and 16600 were obtained, respectively. EITB method based on these antigens was established with the sensitivity and specificity of 92.5% and 100%, respectively, significantly higher than that of ELISA. The sensitivity of serum and filter paper blood was similar in EITB. CONCLUSION: A sensitive and specific EITB method for immunodiagnosis of cysticercosis was established.


Assuntos
Antígenos de Helmintos/sangue , Cisticercose/diagnóstico , Cysticercus/imunologia , Immunoblotting/métodos , Animais , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoeletroforese Bidimensional , Testes Imunológicos , Sensibilidade e Especificidade
13.
J Biotechnol ; 108(2): 161-9, 2004 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-15129725

RESUMO

This study investigated the feasibility of improving the stability of aerobic granules through selecting slow-growing nitrifying bacteria. For this purpose, four sequencing batch reactors were operated at different substrate N/COD ratios ranging from 5/100 to 30/100. Results showed that aerobic granules formed in all four reactors, and aerobic granulation was a gradual process evolving from the dispersed seed sludge to mature and stable granules, and the whole granulation process could be divided into three phases, i.e. acclimation phase, granulation followed by granule maturation. The observed growth rate and mean size of mature aerobic granules were found to decrease as the substrate N/COD ratio was increased, while nitrifying population was enriched markedly in aerobic granules developed at high substrate N/COD ratios. The enriched nitrifying population in aerobic granules was responsible for the observed low growth rate of aerobic granules. It seems certain that the substrate N/COD ratio is an important factor in selecting nitrifying bacteria in aerobic granules. Aerobic granules with low growth rates showed strong structure and good settleability in terms of specific gravity, SVI and cell hydrophobicity that further lead to high stability as compared to those having high growth rates. This study demonstrated that the selection of slow-growing nitrifying bacteria through controlling substrate N/COD ratio would be a useful strategy for improving the stability of aerobic granules.


Assuntos
Bactérias Aeróbias/crescimento & desenvolvimento , Bactérias Aeróbias/metabolismo , Aderência Bacteriana/fisiologia , Reatores Biológicos/microbiologia , Técnicas de Cultura de Células/métodos , Compostos de Nitrogênio/metabolismo , Consumo de Oxigênio/fisiologia , Aerobiose/fisiologia , Bactérias Aeróbias/citologia , Bactérias Aeróbias/isolamento & purificação , Divisão Celular/fisiologia , Controle de Qualidade
14.
J Biotechnol ; 110(3): 251-6, 2004 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-15163515

RESUMO

This study investigated the role of hydrophobic/hydrophilic interaction between bacterial and support surfaces in microbial adhesion, and a model that correlates microbial adhesion and relative cell-hydrophobicity defined as the ratio of cell-support surface hydrophobicity over cell-support hydrophilicity was derived. This model quantitatively describes how cell hydrophobic and hydrophilic interactions affect microbial adhesion, and offers deep insights into the thermodynamic mechanisms of microbial adhesion. The proposed model was verified by literature data. It appears that a high cell-hydrophobicity strongly facilitates microbial adhesion on both hydrophobic and hydrophilic support surfaces.


Assuntos
Aderência Bacteriana , Interações Hidrofóbicas e Hidrofílicas , Especificidade por Substrato/fisiologia , Células Imobilizadas , Modelos Biológicos , Propriedades de Superfície , Termodinâmica
15.
J Biotechnol ; 106(1): 77-86, 2003 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-14636712

RESUMO

Microbial granules were developed at different substrate N/COD ratios in sequencing batch reactors (SBR). Results showed that heterotrophic, nitrifying, and denitrifying populations could peacefully co-exist in microbial granules, while increased substrate N/COD ratio led to significant shifts among three populations in granules. Enhanced activities of nitrifying and denitrifying populations were obtained in microbial granules developed at high substrate N/COD ratios, however, heterotrophic populations in granules tended to decrease with the increase of substrate N/COD ratio. It was found that dissolved oxygen (DO) concentration had a pronounced effect on the efficiency of denitrification by microbial granules, meanwhile the results also indicated that a certain mixing power would be provided to ensure mass transfer between liquid and granules during denitrification. It was demonstrated that complete organics and nitrogen removal can be achieved in single granule-based SBR with high efficiency and stable performance. This is the first study to show the capability of microbial granules in simultaneous removal of organic carbon and nitrogen from wastewater.


Assuntos
Bactérias Aeróbias/metabolismo , Reatores Biológicos/microbiologia , Técnicas de Cultura de Células/métodos , Nitrogênio/farmacocinética , Compostos Orgânicos/farmacocinética , Esgotos/microbiologia , Purificação da Água/métodos , Bactérias Aeróbias/crescimento & desenvolvimento , Biodegradação Ambiental , Consumo de Oxigênio/fisiologia , Tamanho da Partícula , Esgotos/química , Poluentes Químicos da Água/farmacocinética
16.
J Biotechnol ; 102(3): 233-9, 2003 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-12730006

RESUMO

Aerobic granules are microbial aggregates with a strong and compact structure. This study looked into the feasibility of aerobic granules as a novel type of biosorbent for the removal of individual Cd(2+), Cu(2+) and Zn(2+) from aqueous solution. Based on the thermodynamics of biosorption reaction, a general model was developed to describe the equilibrium biosorption of individual Cd(2+), Cu(2+) and Zn(2+) by aerobic granules. This model provides good insights into the thermodynamic mechanisms of biosorption of heavy metals. The model prediction was in good agreement with the experimental data obtained. It was further demonstrated that the Langmuir, Freundlich and Sips or Hill equations were particular cases of the proposed model. The biosorption capacity of individual Cd(2+), Cu(2+) and Zn(2+) on aerobic granules was 172.7, 59.6 and 164.5 mgg(-1), respectively. These values may imply that aerobic granules are effective biosorbent for the removal of Cd(2+), Cu(2+) and Zn(2+) from industrial wastewater.


Assuntos
Bactérias Aeróbias/metabolismo , Biofilmes , Cádmio/farmacocinética , Cobre/farmacocinética , Modelos Biológicos , Modelos Químicos , Zinco/farmacocinética , Adsorção , Aerobiose , Bactérias Aeróbias/química , Bactérias Aeróbias/citologia , Aderência Bacteriana , Reatores Biológicos/microbiologia , Cádmio/química , Simulação por Computador , Cobre/química , Estudos de Viabilidade , Microesferas , Tamanho da Partícula , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/farmacocinética
17.
Curr Microbiol ; 46(4): 270-4, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12732976

RESUMO

Cell hydrophobicity is an important affinity force in cell self-immobilization and attachment processes. The role of cell hydrophobicity in the formation of aerobic granules has not been clear. Therefore, two series of experiments were conducted to investigate the role of cell hydrophobicity in the formation of aerobic heterotrophic and nitrifying granules in sequencing batch reactors, while the effects of shear strength, hydraulic selection pressure, and organic loading rate on the cell hydrophobicity were also studied. Results showed that the formations of heterotrophic and nitrifying granules were associated very closely with the cell hydrophobicity. The hydrophobicity of granular sludge was nearly twofold higher than that of conventional bioflocs. A high shear force or hydraulic selection pressure imposed on microorganisms resulted in a significant increase in the cell hydrophobicity, while the cell hydrophobicity seemed not to be sensitive to the changes in the organic loading rates in the range studied. In conclusion, the cell hydrophobicity could induce and further strengthen cell-cell interaction, and might be a main triggering force to initiate the granulation of heterotrophic and nitrifying bacteria.


Assuntos
Aderência Bacteriana , Aerobiose , Bactérias/citologia , Biomassa , Reatores Biológicos , Interações Hidrofóbicas e Hidrofílicas , Fixação de Nitrogênio/fisiologia
18.
Water Res ; 37(3): 661-73, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12688701

RESUMO

Upflow anaerobic sludge blanket (UASB) reactor has been employed in industrial and municipal wastewater treatment for decades. However, the long start-up period required for the development of anaerobic granules seriously limits the application of this technology. In order to develop the strategy for rapid UASB start-up, the mechanisms for anaerobic granulation should be understood. This paper attempts to provide a up-to-date review on the existing mechanisms and models for anaerobic granulation in the UASB reactor, which include inert nuclei model, selection pressure model, multi-valence positive ion-bonding model, synthetic and natural polymer-bonding model, Capetown's model, spaghetti theory, syntrophic microcolony model, multi-layer model, secondary minimum adhesion model, local dehydration and hydrophobic interaction model, surface tension model, proton translocation-dehydration theory, cellular automaton model and cell-to-cell communication model. Based on those previous works, a general model for anaerobic granulation is also proposed. It is expected that this paper would be helpful for researchers to further develop a unified theory for anaerobic granulation and technology for expediting the formation of the UASB granules.


Assuntos
Aderência Bacteriana , Reatores Biológicos , Modelos Teóricos , Eliminação de Resíduos Líquidos/métodos , Bactérias Anaeróbias/fisiologia , Comunicação Celular , Tamanho da Partícula , Movimentos da Água
19.
Curr Microbiol ; 46(3): 233-4, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12567249

RESUMO

The Monod equation for microbial growth is purely empirical, and the theoretical basis of this model stays unclear. Similar to any chemical reactions, overall microbial growth process is dependent upon the changes in free energy. This study showed that the Monod equation could be interpreted in a thermodynamic sense very well. It was probably for the first time demonstrated that the Monod constant ( K(s)) was inversely related to the equilibrium constant of the overall microbial growth process.


Assuntos
Microbiologia Ambiental , Microbiologia Industrial , Modelos Teóricos , Termodinâmica , Bactérias/crescimento & desenvolvimento , Matemática
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