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1.
RSC Adv ; 14(16): 10905-10919, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38577425

RESUMO

Nitrate-nitrogen pertains to the nitrogen component of the overall nitrate present in a given sample in order to reduce nitrate nitrogen pollution in water, nitrate nitrogen removal methods based on iron-carbon micro-electrolysis have become a key research focus. The process and mechanism of nitrate nitrogen removal by microbial coupling was comprehensively explored in a novel iron-carbon micro-electrolysis (ICME) system. In order to establish the transformation pathway of nitrate nitrogen in water, the transformation paths of nitrate nitrogen in water before and after coupling microorganisms in three groups of continuous flow reaction devices, namely sponge iron (s-Fe0), sponge iron + biochar (s-Fe0/BC) and sponge iron + biochar + manganese sand (s-Fe0/BC/MS), were studied. The morphology and composition changes of sponge iron were analyzed by means of characterization, and the microbial population changes in the three groups were analyzed by high-throughput sequencing. Results showed that the nitrate conversion rate in the s-Fe0, s-Fe0/BC and s-Fe0/BC/MS systems reached 99.48%, 99.57% and 99.36%, respectively, with corresponding ammonia nitrogen generation, rates of 3.77%, 9.34% and 11.24% and nitrogen generation rates of 95.71%, 90.23% and 88.12%. Scanning electron microscopy imaging showed that in the s-Fe0/BC and s-Fe0/BC/MS systems the surface of sponge iron was highly corroded, with granular substances in the corrosion product clusters. X-ray photoelectron spectroscopy analysis found that the relative contents of Fe2O3 in the surface oxides of sponge iron after microbial coupling were 38.02% and 71.27% in the s-Fe0/BC and s-Fe0/BC/MS systems, while the relative Fe3O4 contents were 61.98% and 28.72%, respectively. Microbial high-throughput sequencing analysis revealed that the Chao and Ace index values in the s-Fe0 system were 871.89 and 880.78, while in the s-Fe0/BC system they were 1012.05 and 1017.29, and in the s-Fe0/BC/MS system were 1241.09 and 1198.29, respectively. The relative proportion of Thauera in the s-Fe0, s-Fe0/BC, and s-Fe0/BC/MS systems was 16.76%,14.25% and 10.01%, while the proportion of Acetoanaerobium was 15.36%, 13.27% and 11.11%, and the proportion of Chloroflexi was 0%, 1.11% and 2.18%, respectively. Furthermore, FAPROTAX function annotation found that the expression levels of chemoheterotrophs in the s-Fe0, s-Fe0/BC and s-Fe0/BC/MS systems were 43 316 OTU, 37 289 OTU and 34 205 OTU, while nitrate respiration expression levels were 16 230 OTU, 15 483 OTU and 9149 OTU, with nitrogen respiration expression levels of 16 328 OTU, 15 493 OTU and 9154 OTU, respectively. These findings suggest that nitrate is converted into nitrogen gas and ammonia nitrogen through the actions of the coupled system of sponge iron/biochar/manganese sand and microorganisms. The catalytic effect of MnO2 promotes the conversion of Fe2+ to Fe3+, generating more electrons, allowing denitrifying bacteria to reduce more nitrate nitrogen, effectively coupling the manganese-catalyzed ICME reaction and microbial denitrification. The micro-electrolysis system and the addition of manganese sand enhanced biodiversity within the s-Fe0/BC/MS system. The heterotrophic bacteria Thauera and Acetoanaerobium were the dominant microorganisms in all three systems, although the micro-electrolysis system with added manganese sand significantly reduced the proportion of facultative bacteria Thauera and Acetoanaerobium and promoted the growth of autotrophic Chloroflexi bacteria. The ecological functions of the three systems were mainly nitrate respiration and nitrogen respiration. By comparing the expression levels of nitrate respiration and nitrogen respiration in s-Fe0/BC and s-Fe0/BC/MS systems, it can be seen that the addition of manganese sand reduced microbial activity.

2.
Sensors (Basel) ; 22(22)2022 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-36433573

RESUMO

The objective of the proposed human-machine cooperation (HMC) workstation is to both rapidly detect calcium-based fish bones in masses of minced fish floss and visually guide operators in approaching and removing the detected fish bones by hand based on the detection of fingernails or plastic-based gloves. Because vibration is a separation mechanism that can prevent absorption or scattering in thick fish floss for UV fluorescence detection, the design of the HMC workstation included a vibration unit together with an optical box and display screens. The system was tested with commonly used fish (swordfish, salmon, tuna, and cod) representing various cooking conditions (raw meat, steam-cooked meat, and fish floss), their bones, and contaminating materials such as derived from gloves made of various types of plastic (polyvinylchloride, emulsion, and rubber) commonly used in the removal of fish bones. These aspects were each investigated using the spectrum analyzer and the optical box to obtain and analyze the fluorescence spectra and images. The filter was mounted on a charge-coupled device, and its transmission-wavelength window was based on the characteristic band for fish bones observed in the spectra. Gray-level AI algorithm was utilized to generate white marker rectangles. The vibration unit supports two mechanisms of air and downstream separation to improve the imaging screening of fish bones inside the considerable flow of fish floss. Notably, under 310 nm ultraviolet B (UVB) excitation, the fluorescence peaks of the raw fillets, steam-cooked meat, and fish floss were observed at for bands at longer wavelengths (500-600 nm), whereas those of the calcium and plastic materials occurred in shorter wavelength bands (400-500 nm). Perfect accuracy of 100% was achieved with the detection of 20 fish bones in 2 kg of fish floss, and the long test time of around 10-12 min results from the manual removal of these fish bones.


Assuntos
Cálcio , Vibração , Animais , Humanos , Fluorescência , Vapor , Peixes , Tecnologia , Plásticos
3.
ACS Omega ; 7(7): 5646-5656, 2022 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-35224326

RESUMO

The temperature/pH dual-responsive gel spheres were prepared by orthogonal experiments and response surface methodology, and finally, the optimal synthesis conditions were obtained by a composite score, including swelling, mechanical properties, mass transfer properties, and so forth. The results showed that a sodium alginate concentration of 3% (w/v), CaCl2 concentration of 2% (w/v), gelling time of 40 h, drop height of 14 cm, NaCl concentration of 0.6% (w/v), N-isopropylacrylamide concentration of 0.03% (w/v), and acrylic acid concentration of 4.06% (w/v) were optimal synthesis conditions. The environmental change tolerance experiments showed that the nitrogen removal of the dual-response nitrifying gel spheres was better than the domesticated sludge at low temperatures (4 °C) and in alkaline (pH 9 and 10) conditions. The as-obtained gel spheres can respond intelligently to the changes in ambient temperature and pH. It is hoped that this study will provide technical parameters for the development and application of microbial immobilization carriers.

4.
Biosensors (Basel) ; 11(10)2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34677319

RESUMO

Infections of orchids by the Odontoglossum ringspot virus or Cymbidium mosaic virus cause orchid disfiguration and are a substantial source of economic loss for orchid farms. Although immunoassays can identify these infections, immunoassays are expensive, time consuming, and labor consuming and limited to sampling-based testing methods. This study proposes a noncontact inspection platform that uses a spectrometer and Android smartphone. When orchid leaves are illuminated with a handheld optical probe, the Android app based on the Internet of Things and artificial intelligence can display the measured florescence spectrum and determine the infection status within 3 s by using an algorithm hosted on a remote server. The algorithm was trained on optical data and the results of polymerase chain reaction assays. The testing accuracy of the algorithm was 89%. The area under the receiver operating characteristic curve was 91%; thus, the platform with the algorithm was accurate and convenient for infection screening in orchids.


Assuntos
Orchidaceae , Smartphone , Inteligência Artificial , Doenças das Plantas/virologia , Reação em Cadeia da Polimerase , Potexvirus , Tobamovirus
5.
Zhongguo Zhong Yao Za Zhi ; 46(7): 1839-1845, 2021 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-33982489

RESUMO

According to the notice on revision of the instructions for traditional Chinese medicine injections(TCMIs) issued by the National Medical Products Administration(NMPA) from January 2006 to May 2020, the revised contents in the instructions for 29 varieties involved in the notice were sorted out, and the existing problems in the instructions for TCMIs were analyzed, so as to provide the basis for dynamic revision of the instructions. It was found that the revised items of instructions for 29 varieties all involved adverse reactions, contraindications and precautions, and warnings were added for 82.76% of 29 TCMIs preparations, indicating that all the revised contents were related to safety issues. In addition, 33.33% of the drugs risks mentioned in the precautions were not indicated in the adverse reactions; 82.76% instructions did not indicate drug interactions; 17.24% instructions lacked medication notes for special populations; 48.28% instructions did not indicate traditional Chinese medicine(TCM) syndromes of the main disease; 44.83% instructions did not indicate the type and stage of indication; and 86.21% instructions did not indicate the course of treatment. It could be concluded that the instructions for TCMIs have known risks of drugs that are not fully reflected in adverse reactions and the effective information is not comprehensive. The risk control measures proposed in the precautions need to have aftereffect evaluation and there is a lack of drug interactions and medications for special populations. As an important part of the full life-cycle management of drugs, the revision of instructions for TCMIs should be continuously improved to provide the basis for safe and reasonable application of TCMIs. Based on the above problems, it is proposed that the marketing license holder as the main body of the revision of instructions should actively carry out post-marketing basic and clinical research in accordance with the characteristics of TCM, combine the updated research with the guidance of TCM theory and improve the revision level of instructions for TCMIs to provide the basis for post-marketing evaluation.


Assuntos
Medicamentos de Ervas Chinesas , Medicina Tradicional Chinesa , Humanos , Injeções , Síndrome
6.
Chin J Integr Med ; 27(7): 483-489, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33170939

RESUMO

Although there is guidance from different regulatory agencies, there are opportunities to bring greater consistency and stronger applicability to address the practical issues of establishing and operating a data monitoring committee (DMC) for clinical studies of Chinese medicine. We names it as a Chinese Medicine Data Monitoring Committee (CMDMC). A panel composed of clinical and statistical experts shared their experience and thoughts on the important aspects of CMDMCs. Subsequently, a community standard on CMDMCs (T/CACM 1323-2019) was issued by the China Association of Chinese Medicine on September 12, 2019. This paper summarizes the key content of this standard to help the sponsors of clinical studies establish and operate CMDMCs, which will further develop the scientific integrity and quality of clinical studies.


Assuntos
Comitês de Monitoramento de Dados de Ensaios Clínicos , Medicina Tradicional Chinesa , China
7.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-879099

RESUMO

According to the notice on revision of the instructions for traditional Chinese medicine injections(TCMIs) issued by the National Medical Products Administration(NMPA) from January 2006 to May 2020, the revised contents in the instructions for 29 varieties involved in the notice were sorted out, and the existing problems in the instructions for TCMIs were analyzed, so as to provide the basis for dynamic revision of the instructions. It was found that the revised items of instructions for 29 varieties all involved adverse reactions, contraindications and precautions, and warnings were added for 82.76% of 29 TCMIs preparations, indicating that all the revised contents were related to safety issues. In addition, 33.33% of the drugs risks mentioned in the precautions were not indicated in the adverse reactions; 82.76% instructions did not indicate drug interactions; 17.24% instructions lacked medication notes for special populations; 48.28% instructions did not indicate traditional Chinese medicine(TCM) syndromes of the main disease; 44.83% instructions did not indicate the type and stage of indication; and 86.21% instructions did not indicate the course of treatment. It could be concluded that the instructions for TCMIs have known risks of drugs that are not fully reflected in adverse reactions and the effective information is not comprehensive. The risk control measures proposed in the precautions need to have aftereffect evaluation and there is a lack of drug interactions and medications for special populations. As an important part of the full life-cycle management of drugs, the revision of instructions for TCMIs should be continuously improved to provide the basis for safe and reasonable application of TCMIs. Based on the above problems, it is proposed that the marketing license holder as the main body of the revision of instructions should actively carry out post-marketing basic and clinical research in accordance with the characteristics of TCM, combine the updated research with the guidance of TCM theory and improve the revision level of instructions for TCMIs to provide the basis for post-marketing evaluation.


Assuntos
Humanos , Medicamentos de Ervas Chinesas , Injeções , Medicina Tradicional Chinesa , Síndrome
8.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-888672

RESUMO

Although there is guidance from different regulatory agencies, there are opportunities to bring greater consistency and stronger applicability to address the practical issues of establishing and operating a data monitoring committee (DMC) for clinical studies of Chinese medicine. We names it as a Chinese Medicine Data Monitoring Committee (CMDMC). A panel composed of clinical and statistical experts shared their experience and thoughts on the important aspects of CMDMCs. Subsequently, a community standard on CMDMCs (T/CACM 1323-2019) was issued by the China Association of Chinese Medicine on September 12, 2019. This paper summarizes the key content of this standard to help the sponsors of clinical studies establish and operate CMDMCs, which will further develop the scientific integrity and quality of clinical studies.

9.
Zhongguo Zhong Yao Za Zhi ; 44(2): 405-408, 2019 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-30989964

RESUMO

Congchi Decoction in Zhouhou Beiji Fang is a prescription commonly used in treating light exterior wind-cold syndrome.Fistular Onion Stalk in the prescription has the effects in inducing sweat and dispelling exogenous evils and accelerating Yang Qi,and has been recorded in many medical books. In addition to be used to treat light exterior wind-cold syndrome,Fistular Onion Stalk is also used extensively and uniquely to treat restlessness after cholera,febrile disease,thoracic obstruction,Yin-Yang toxin syndrome,consumptive disease,bellyache due to spleen Qi deficiency according to Zhouhou Beiji Fang. However,there is still lack of the research on whether Fistular Onion Stalk is derived from shallot or scallion. The authors analyzed the sources of Fistular Onion Stalk in the prescription of Congchi Decoction by consulting ancient books,and studying the plant morphology of shallot,the characteristic and effect of Fistular Onion Stalk and the historical physicians' clinical application of Fistular Onion Stalk,the completion and popularity of Zhouhou Beiji Fang,the ratio of water to medicine of Congchi Decoction and the chemical ingredients of Fistular Onion Stalk. Finally,the authors concluded that Fistular Onion Stalk in the Congchi Decoction refers to Scallion bulbs.


Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Cebolas/química , Yin-Yang , Humanos , Medicina Tradicional Chinesa
10.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-774590

RESUMO

Congchi Decoction in Zhouhou Beiji Fang is a prescription commonly used in treating light exterior wind-cold syndrome.Fistular Onion Stalk in the prescription has the effects in inducing sweat and dispelling exogenous evils and accelerating Yang Qi,and has been recorded in many medical books. In addition to be used to treat light exterior wind-cold syndrome,Fistular Onion Stalk is also used extensively and uniquely to treat restlessness after cholera,febrile disease,thoracic obstruction,Yin-Yang toxin syndrome,consumptive disease,bellyache due to spleen Qi deficiency according to Zhouhou Beiji Fang. However,there is still lack of the research on whether Fistular Onion Stalk is derived from shallot or scallion. The authors analyzed the sources of Fistular Onion Stalk in the prescription of Congchi Decoction by consulting ancient books,and studying the plant morphology of shallot,the characteristic and effect of Fistular Onion Stalk and the historical physicians' clinical application of Fistular Onion Stalk,the completion and popularity of Zhouhou Beiji Fang,the ratio of water to medicine of Congchi Decoction and the chemical ingredients of Fistular Onion Stalk. Finally,the authors concluded that Fistular Onion Stalk in the Congchi Decoction refers to Scallion bulbs.


Assuntos
Humanos , Medicamentos de Ervas Chinesas , Farmacologia , Medicina Tradicional Chinesa , Cebolas , Química , Yin-Yang
11.
Zhongguo Zhong Yao Za Zhi ; 42(21): 4059-4066, 2017 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-29271140

RESUMO

Through a systematic and comprehensive study of domestic and foreign literatures and information, this study aims to trace the herbal origin and the toxicity recorded in ancient and current documents, analyze the safety case reports of Psoralea corylifolia and experimental studies on toxicity in recent years, and make a preliminary summary about the clinical characteristics and potential risk factors of cases related to the safety of P. corylifolia and its preparations. The study involved 84 patients in the safety case reports of P. corylifolia. The adverse events were mainly liver damage (55.95%) and light toxic contact dermatitis (38.10%), sugguesting that P. corylifolia may lead to liver damage and photo toxicity. However, reproductive toxicity and renal damage were only reported in animal studies, but not in clinical reports. Because of its complicated ingredients, the toxic components and mechanisms of P. corylifolia have not been clear at present. Therefore, the authors proposed to strictly apply P. corylifolia in clinic, use it rationally and combine it with other medications. Besides, efforts shall be made to strength the guidance for doctors, the safety monitoring of P. corylifolia and relevant preparations, and actively carry out safety-related basic and clinical studies, so as to give a better guidance to safe medication, full exert the efficacy and avoid the medication risk.


Assuntos
Medicamentos de Ervas Chinesas/toxicidade , Plantas Medicinais/toxicidade , Psoralea/toxicidade , Animais , Medicamentos de Ervas Chinesas/normas , Humanos
12.
Zhongguo Zhong Yao Za Zhi ; 42(21): 4067-4073, 2017 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-29271141

RESUMO

The authors systemically evaluated and analyzed the safety of Areca catechu from domestic and foreign literatures about the herbal origin, toxicity recorded in ancient/current documents, safety case reports of clinical A. catechu, experimental studies on toxicity in recent years, and differences of safety risk between edible and medicinal A. catechu. Subsequently, they proposed a preliminary summary about the clinical characteristics and potential risk factors of safety related cases of A. catechu and its preparations. According to the authors, although clinical adverse events of A. catechu were fewer and controllable, clinicians shall stillstrictly standardize its application, and rationally combine it with other herbs, while strengthening fundamental and clinical studies related to safety, so as to give better guidance to safety application of A. catechu in clinic.


Assuntos
Areca/toxicidade , Medicamentos de Ervas Chinesas/toxicidade , Medicamentos de Ervas Chinesas/normas , Humanos , Medicina Tradicional Chinesa
13.
Zhongguo Zhong Yao Za Zhi ; 42(21): 4079-4085, 2017 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-29271143

RESUMO

By retrieving domestic and foreign literatures, the authors provided a systematic review for effects of Xanthii Fructus, toxicity recorded in ancient/current literatures and relevant toxicological experience, and summarized clinical characteristics of clinical cases related to Xanthii Fructus and influencing factors. In addition to liver and kidney injuries as the major side effects of Xanthii Fructus, neurotoxicity and cardio-toxicity of Xanthii Fructus were also common clinical adverse events. However, there have been a few animal experimental studies so far. Oral administration and external application with Xanthii Fructus have often caused skin reactions, even such severe cases as exfoliative dermatitis. The authors suggested standardizing the clinical medication, avoiding to use untreated prescriptions and unprocessed herbs, ensuring the effective and safety use of Xanthii Fructus in strict accordance with the recommended dosage and usage in pharmacopeia, paying attention to the accumulation of safety signals, strengthening studies on toxic substance, toxicity mechanism, and synergy and attenuation effects.


Assuntos
Medicamentos de Ervas Chinesas/toxicidade , Frutas/toxicidade , Xanthium/toxicidade , Animais , Doença Hepática Induzida por Substâncias e Drogas , Humanos , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos
14.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-335742

RESUMO

Through a systematic and comprehensive study of domestic and foreign literatures and information, this study aims to trace the herbal origin and the toxicity recorded in ancient and current documents, analyze the safety case reports of Psoralea corylifolia and experimental studies on toxicity in recent years, and make a preliminary summary about the clinical characteristics and potential risk factors of cases related to the safety of P. corylifolia and its preparations. The study involved 84 patients in the safety case reports of P. corylifolia. The adverse events were mainly liver damage (55.95%) and light toxic contact dermatitis (38.10%), sugguesting that P. corylifolia may lead to liver damage and photo toxicity. However, reproductive toxicity and renal damage were only reported in animal studies, but not in clinical reports. Because of its complicated ingredients, the toxic components and mechanisms of P. corylifolia have not been clear at present. Therefore, the authors proposed to strictly apply P. corylifolia in clinic, use it rationally and combine it with other medications. Besides, efforts shall be made to strength the guidance for doctors, the safety monitoring of P. corylifolia and relevant preparations, and actively carry out safety-related basic and clinical studies, so as to give a better guidance to safe medication, full exert the efficacy and avoid the medication risk.

15.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-335741

RESUMO

The authors systemically evaluated and analyzed the safety of Areca catechu from domestic and foreign literatures about the herbal origin, toxicity recorded in ancient/current documents, safety case reports of clinical A. catechu, experimental studies on toxicity in recent years, and differences of safety risk between edible and medicinal A. catechu. Subsequently, they proposed a preliminary summary about the clinical characteristics and potential risk factors of safety related cases of A. catechu and its preparations. According to the authors, although clinical adverse events of A. catechu were fewer and controllable, clinicians shall stillstrictly standardize its application, and rationally combine it with other herbs, while strengthening fundamental and clinical studies related to safety, so as to give better guidance to safety application of A. catechu in clinic.

16.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-335739

RESUMO

By retrieving domestic and foreign literatures, the authors provided a systematic review for effects of Xanthii Fructus, toxicity recorded in ancient/current literatures and relevant toxicological experience, and summarized clinical characteristics of clinical cases related to Xanthii Fructus and influencing factors. In addition to liver and kidney injuries as the major side effects of Xanthii Fructus, neurotoxicity and cardio-toxicity of Xanthii Fructus were also common clinical adverse events. However, there have been a few animal experimental studies so far. Oral administration and external application with Xanthii Fructus have often caused skin reactions, even such severe cases as exfoliative dermatitis. The authors suggested standardizing the clinical medication, avoiding to use untreated prescriptions and unprocessed herbs, ensuring the effective and safety use of Xanthii Fructus in strict accordance with the recommended dosage and usage in pharmacopeia, paying attention to the accumulation of safety signals, strengthening studies on toxic substance, toxicity mechanism, and synergy and attenuation effects.

17.
J Biosci Bioeng ; 121(4): 450-6, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26750640

RESUMO

An anaerobic rotating biological contactor was fed with inorganic synthetic wastewater for anammox. Besides biofilm, granular biomass with average diameter of approximately 5 mm formed. NH4(+), NO2(-), NO3(-) and pH microelectrodes were used to probe microbial activity in situ within the granules. At a sufficient substrate concentration, the anammox reaction was observed in the upper layer of granules, and the most active zone was found to be in the surface of 200-400 µm. The in situ anammox activity increased with increasing substrate concentration, and a maximum ammonium consumption rate of 83.3 µmol cm(-3) h(-1) was obtained at an ammonium concentration of 1000 µmol L(-1). Under an ammonium-limited condition, denitrification activity was observed in the inner layer, and the most active zone was limited to 700-1000 µm. This study revealed that denitrification bacteria coexisted with anammox bacteria within inorganic anammox granules.


Assuntos
Compostos de Amônio/metabolismo , Bactérias/metabolismo , Biomassa , Reatores Biológicos/microbiologia , Águas Residuárias/química , Águas Residuárias/microbiologia , Anaerobiose , Biofilmes , Desnitrificação , Concentração de Íons de Hidrogênio , Microeletrodos , Ciclo do Nitrogênio , Oxirredução , Rotação
18.
J Biosci Bioeng ; 120(4): 419-25, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25792185

RESUMO

A laboratory-scale sequencing batch reactor fed with synthetic high-ammonium wastewater was operated for autotrophic partial nitritation, and the characteristics of N2O emission were investigated by both macro- and microanalysis. A N2O emission quantity of 5.98 ± 1.24 mg (n = 17) was observed, accounting for 0.997% ± 0.408% of the influent nitrogen. The N2O level in the off-gas first increased to a maximum of 91.5 ppmv in the initial 50 min, and then decreased and remained around 34.8 ppmv until the end of aeration. An asymptotic function (y = 14.3-14.2 × 0.992(x), R(2) = 0.997) could be used to estimate the quantity of N2O emitted. Microelectrodes were used to explore the variations in the nitrogen distribution and consumption rate within sludge flocs as the reaction proceeded. During the aeration phase, partial nitritation occurred mainly in the surface layer of flocs. This is where most N2O was produced, indicating that N2O was generated as a byproduct of the nitritation. During the settling phase, the N2O concentration and volumetric production rate were much higher than those in the aeration phase, suggesting that the settling phase contributes to the initial N2O emission peak.


Assuntos
Processos Autotróficos , Reatores Biológicos , Nitritos/química , Óxido Nitroso/análise , Compostos de Amônio/química , Técnicas de Cultura Celular por Lotes , Nitrogênio/química , Esgotos/química , Águas Residuárias/química
19.
Environ Sci Technol ; 47(8): 3708-14, 2013 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-23528200

RESUMO

To further unravel the organic fouling behavior of polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes, the adhesion forces of membrane-foulant and foulant-foulant were investigated by atomic force microscopy (AFM) in conjunction with self-made PVDF colloidal probe and foulant-coated colloidal probe, respectively. Fouling experiments with bovine serum albumin, sodium alginate, humic acid, and secondary wastewater effluent organic matter (EfOM) were carried out with PVDF UF membrane. Results showed a positive correlation between the membrane-foulant adhesion force and the flux decline rate and extent in the initial filtration stage, whereas the foulant-foulant interaction force was closely related to the pseudostable flux and the cake layer structure in the later filtration stage. For each type of foulant used, the membrane-foulant adhesion force was much stronger than the foulant-foulant interaction force, and membrane flux decline mainly occurred in the earlier filtration stage indicating that elimination of the membrane-foulant interaction force is important for the control of membrane fouling. Upon considering the foulant-foulant interaction force and the membrane flux recovery rate of fouled membranes, it was evident that the main contributor to physically irreversible fouling is the foulant-foulant interaction force.


Assuntos
Incrustação Biológica , Membranas Artificiais , Compostos Orgânicos/análise , Fenômenos Físicos , Polivinil/química , Ultrafiltração , Adesividade , Alginatos/análise , Animais , Bovinos , Coloides/química , Ácido Glucurônico/análise , Ácidos Hexurônicos/análise , Substâncias Húmicas/análise , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Soroalbumina Bovina/análise
20.
J Org Chem ; 75(16): 5743-5, 2010 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-20704448

RESUMO

A series of 4-arylsulfonylimino-4,5-dihydrofurans (14 examples) were efficiently synthesized in good to excellent yields by using the copper-catalyzed three-component reaction between sulfonyl azides, phenylacetylene, and beta-ketoesters in tetrahydrofuran (THF) at 40 degrees C for 8 h in the presence of triethylamine (TEA). A plausible mechanism for this process is proposed.


Assuntos
Cobre/química , Furanos/síntese química , Iodetos/química , Catálise , Furanos/química , Estrutura Molecular , Estereoisomerismo
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