Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 159
Filtrar
1.
Chem Rev ; 123(8): 4635-4662, 2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-36917618

RESUMO

This review presents an exhaustive overview on the mechanisms of Fe3+ cathodic reduction within the context of the electro-Fenton (EF) process. Different strategies developed to improve the reduction rate are discussed, dividing them into two categories that regard the mechanistic feature that is promoted: electron transfer control and mass transport control. Boosting the Fe3+ conversion to Fe2+ via electron transfer control includes: (i) the formation of a series of active sites in both carbon- and metal-based materials and (ii) the use of other emerging strategies such as single-atom catalysis or confinement effects. Concerning the enhancement of Fe2+ regeneration by mass transport control, the main routes involve the application of magnetic fields, pulse electrolysis, interfacial Joule heating effects, and photoirradiation. Finally, challenges are singled out, and future prospects are described. This review aims to clarify the Fe3+/Fe2+ cycling process in the EF process, eventually providing essential ideas for smart design of highly effective systems for wastewater treatment and valorization at an industrial scale.

2.
Environ Sci Technol ; 57(38): 14482-14492, 2023 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-37699122

RESUMO

It is critical to discover a non-noble metal catalyst with high catalytic activity capable of replacing palladium in electrochemical reduction. In this work, a highly efficient single-atom Co-N/C catalyst was synthesized with metal-organic frameworks (MOFs) as a precursor for electrochemical dehalogenation. X-ray absorption spectroscopy (XAS) revealed that Co-N/C exhibited a Co-N4 configuration, which had more active sites and a faster charge-transfer rate and thus enabled the efficient removal of florfenicol (FLO) at a wide pH, achieving a rate constant 3.5 and 2.1 times that of N/C and commercial Pd/C, respectively. The defluorination and dechlorination efficiencies were 67.6 and 95.6%, respectively, with extremely low Co leaching (6 µg L-1), low energy consumption (22.7 kWh kg-1), and high turnover frequency (TOF) (0.0350 min-1), demonstrating excellent dehalogenation performance. Spiking experiments and density functional theory (DFT) verified that Co-N4 was the active site and had the lowest energy barrier for forming atomic hydrogen (H*) (ΔGH*). Capture experiments, electron paramagnetic resonance (EPR), electrochemical tests, and in situ Fourier transform infrared (FTIR) proved that H* and direct electron transfer were responsible for dehalogenation. Toxicity assessment indicated that FLO toxicity decreased significantly after dehalogenation. This work develops a non-noble metal catalyst with broad application prospects in electrocatalytic dehalogenation.


Assuntos
Cobalto , Paládio , Catálise , Espectroscopia de Ressonância de Spin Eletrônica
3.
J Environ Manage ; 342: 118276, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37276627

RESUMO

High N-fertilizer applications to conventional vegetable production systems are associated with substantial emissions of NH3, a key substance that triggers haze pollution and ecosystem eutrophication and thus, causing considerable damage to human and ecosystem health. While N fertilization effects on NH3 volatilization from cereal crops have been relatively well studied, little is known about the magnitude and yield-scaled emissions of NH3 from vegetable systems. Here we report on a 2-year field study investigating the effect of various types and rates of fertilizer application on NH3 emissions and crop yields for a pepper-lettuce-cabbage rotation system in southwest China. Our results show that both NH3 emissions and direct emission factors of applied N varied largely across seasons over the 2-year period, highlighting the importance of measurements spanning entire cropping years. Across all treatments varying from solely applying urea fertilizers to only using organic manures, annual NH3 emissions ranged from 0.64 to 92.4 kg N ha-1 yr-1 (or 0.07-6.84 g N kg-1 dry matter), equivalent to 0.05-5.99% of the applied N. At annual scale, NH3 emissions correlated positively with soil δ15N values, indicating that soil δ15N may be used as an indicator for NH3 losses. NH3 emissions from treatments fertilized partially or fully with manure were significantly lower compared with the urea fertilized treatment, while vegetable yields remained unaffected. Moreover, full substitution of urea by manure as compared to the partial substitution further reduced the yield-scaled annual NH3 emissions by 79.0-92.4%. Across all vegetable seasons, there is a significant negative relationship between yield-scaled NH3 emissions and crop N use efficiency. Overall, our results suggest that substituting urea by manure and reducing total N inputs by 30-50% allows to reduce NH3 emissions without jeopardizing yields. Such a change in management provides a feasible option to achieve environmental sustainability and food security in conventional vegetable systems.


Assuntos
Nitrogênio , Verduras , Humanos , Agricultura/métodos , Óxido Nitroso/análise , Fertilizantes/análise , Esterco , Ecossistema , Solo , Ureia , China , Amônia
4.
J Environ Sci (China) ; 127: 652-666, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36522094

RESUMO

An ultra-efficient electro-Fenton catalyst with porous carbon coated Fe-Mo metal (FeMo@PC), was prepared by calcining MIL-53(Fe)@MoO3. This FeMo@PC-2 exhibited impressive catalytic performance for sulfamethazine (SMT) degradation with a high turnover frequency value (7.89 L/(g·min)), much better than most of reported catalysts. The mineralization current efficiency and electric energy consumption were 83.2% and 0.03 kWh/gTOC, respectively, at low current (5 mA) and small dosage of catalyst (25.0 mg/L). The removal rate of heterogeneous electro-Fenton (Hetero-EF) process catalyzed by FeMo@PC-2 was 4.58 times that of Fe@PC/Hetero-EF process. Because the internal-micro-electrolysis occurred between PC and Fe0, while the co-catalysis of Mo accelerated the rate-limiting step of the Fe3+/Fe2+ cycle and greatly improved the H2O2 utilization efficiency. The results of radical scavenger experiments and electron paramagnetic resonance confirmed the main role of surface-bound hydroxyl radical oxidation. This process was feasible to remove diverse organic contaminants such as phenol, 2,4-dichlorophenoxyacetic acid, carbamazepine and SMT. This paper enlightened the importance of the doped Mo, which could greatly improve the activity of the iron-carbon heterogeneous catalyst derived from metal-organic frameworks in EF process for efficient removal of organic contaminants.


Assuntos
Peróxido de Hidrogênio , Poluentes Químicos da Água , Carbono , Catálise , Oxirredução , Porosidade , Sulfametazina , Poluentes Químicos da Água/análise
5.
Agron Sustain Dev ; 43(2): 27, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36909277

RESUMO

The great challenge of reducing soil nutrient depletion and assuring agricultural system productivity in low-income countries caused by limited synthetic fertilizer use necessitates local and cost-effective nutrient sources. We estimated the changes of the nitrogen budget of agricultural systems in the East African Community from 1961 to 2018 to address the challenges of insufficient nitrogen inputs and serious soil nitrogen depletion in agricultural systems of the East African Community region. Results showed that total nitrogen input increased from 12.5 kg N ha-1yr-1 in the 1960s to 21.8 kg N ha-1yr-1 in the 2000s and 27 kg N ha-1yr-1 in the 2010s. Total nitrogen crop uptake increased from 12.8 kg N ha-1yr-1 in the 1960s to 18.2 kg N ha-1yr-1 in the 2000s and 21.8 kg N ha-1yr-1 in the 2010s. Soil nitrogen stock increased from -2.0 kg N ha-1yr-1 in the 1960s to -0.5 kg N ha-1yr-1 in the 2000s and 0.3 kg N ha-1yr-1 in the 2010s. Our results allow us to substantiate for the first time that soil nitrogen depletion decreases with increasing input of nitrogen in agricultural systems of the East African Community region. This suggests that increases in nitrogen inputs through biological nitrogen fixation and animal manure are the critical nitrogen management practices to curb soil nitrogen depletion and sustain agricultural production systems in the East African Community region in order to meet food demand for a growing population. Supplementary Information: The online version contains supplementary material available at 10.1007/s13593-023-00881-0.

6.
Environ Res ; 212(Pt D): 113544, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35643309

RESUMO

Water regimes strongly impact soil C and N cycling and the associated greenhouse gases (GHGs, i.e., CO2, CH4 and N2O). Therefore, a study was conducted to examine the impacts of flooding-drying of soil along with application of nitrogen (N) fertilizer and nitrification inhibitor dicyandiamide (DCD) on GHGs emissions. This study comprised four experimental treatments, including (i) control (CK), (ii) dicyandiamide, 20 mg kg-1 (DCD), (iii) nitrogen fertilizer, 300 mg kg-1 (N) and (iv) DCD + N. All experimental treatments were kept under flooded condition at the onset of the experiment, and then converted to 60% water filled pore space (WFPS). At flooding stage, N2O emissions were lower as compared to 60% WFPS. The highest cumulative N2O emission was 0.98 mg N2O-N kg-1 in N treated soil due to high substrates of mineral N contents, but lowest (0.009 mg N2O-N kg-1) in the DCD treatment. The highest cumulative CH4 emissions (80.54 mg CH4-C kg-1) were observed in the N treatment, while uptake of CH4 was observed in the DCD treatment. As flooded condition converted to 60% WFPS, CO2 emissions gradually increased in all experimental treatments, but the maximum cumulative CO2 emission was 477.44 mg kg-1 in the DCD + N treatment. The maximum dissolved organic carbon (DOC) contents were observed in N and DCD + N treatments with the values of 57.12 and 58.92 mg kg-1, respectively. Microbial biomass carbon (MBC) contents were higher at flooding while lower at transition phase, and increased at the initiation of 60% WFPS stage. However, MBC contents declined at the later stage of 60% WFPS. The maximum MBC contents were 202.12 and 192.41 mg kg-1 in N and DCD + N treatments, respectively. Results demonstrated that water regimes exerted a dramatic impact on C and N dynamics, subsequently GHGs, which were highly controlled by DCD at both flooding and 60% WFPS conditions.


Assuntos
Fertilizantes , Solo , Agricultura/métodos , Carbono , Dióxido de Carbono/análise , Fertilizantes/análise , Guanidinas , Metano , Nitrogênio/análise , Óxido Nitroso , Solo/química , Água/química
7.
Glob Chang Biol ; 27(12): 2807-2821, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33742490

RESUMO

Globally, about 50% of all arable soils are classified as acidic. As crop and plant growth are significantly hampered under acidic soil conditions, many farmers, but increasingly as well forest managers, apply lime to raise the soil pH. Besides its direct effect on soil pH, liming also affects soil C and nutrient cycles and associated greenhouse gas (GHG) fluxes. In this meta-analysis, we reviewed 1570 observations reported in 121 field-based studies worldwide, to assess liming effects on soil GHG fluxes and plant productivity. We found that liming significantly increases crop yield by 36.3%. Also, soil organic C (SOC) stocks were found to increase by 4.51% annually, though soil respiration is stimulated too (7.57%). Moreover, liming was found to reduce soil N2 O emission by 21.3%, yield-scaled N2 O emission by 21.5%, and CH4 emission and yield-scaled CH4 emission from rice paddies by 19.0% and 12.4%, respectively. Assuming that all acid agricultural soils are limed periodically, liming results in a total GHG balance benefit of 633-749 Tg CO2 -eq year-1 due to reductions in soil N2 O emissions (0.60-0.67 Tg N2 O-N year-1 ) and paddy soil CH4 emissions (1.75-2.21 Tg CH4  year-1 ) and increases in SOC stocks (65.7-110 Tg C year-1 ). However, this comes at the cost of an additional CO2 release (c. 624-656 Tg CO2  year-1 ) deriving from lime mining, transport and application, and lime dissolution, so that the overall GHG balance is likely neutral. Nevertheless, liming of acid agricultural soils will increase yields by at least 6.64 × 108  Mg year-1 , covering the food supply of 876 million people. Overall, our study shows for the first time that a general strategy of liming of acid agricultural soils is likely to result in an increasing sustainability of global agricultural production, indicating the potential benefit of liming acid soils for climate change mitigation and food security.


Assuntos
Mudança Climática , Solo , Agricultura , Compostos de Cálcio , Dióxido de Carbono/análise , Segurança Alimentar , Humanos , Metano/análise , Óxido Nitroso/análise , Óxidos
8.
Molecules ; 26(13)2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34206683

RESUMO

Crystalline materials containing hybrid inorganic-organic metal borates (complexes with oxidoborate ligands) display a variety of novel framework building blocks. The structural aspects of these hybrid metallaoxidoborates containing Cd(II), Co(II), Cu(II), Ga(III), In(III), Mn(II), Ni(II) or Zn(II) metal centers are discussed in this review. The review describes synthetic approaches to these hybrid materials, their physical properties, their spectroscopic properties and their potential applications.

9.
Cytotherapy ; 21(2): 125-147, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30554868

RESUMO

BACKGROUND AIMS: Cytokine-induced killer (CIK) cells are the most commonly used cellular immunotherapy for multiple tumors. To further confirm whether chemotherapy with CIK cells improves clinical effectiveness and to reveal its optimal use in non-small cell lung cancer (NSCLC), we systematically reevaluated all relevant studies. METHODS: We collected all studies about chemotherapy with CIK cells for NSCLC from the Medline, Embase, Web of Science, China National Knowledge Infrastructure Database (CNKI), Chinese Scientific Journals Full-Text Database (VIP), Wanfang Data, China Biological Medicine Database (CBM), Cochrane Central Register of Controlled Trials (CENTRAL), Chinese clinical trial registry (Chi-CTR), World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and U.S. clinical trials. We evaluated their quality according to the Cochrane evaluation handbook of randomized controlled trials (RCTs) (version 5.1.0), extracted the data using a standard data extraction form, synthesized the data using meta-analysis and finally rated the evidence quality using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. RESULTS: Thirty-two RCTs with 2250 patients were included, and most trials had unclear risk of bias. The merged risk ratios values and their 95% confidence intervals of meta-analysis for objective response rate, disease control rate, 1- and 2-year overall survival rates, 1- and 2-year progression-free survival rates were as following: 1.45 (1.31-1.61), 1.26 (1.16-.37), 1.42 (1.23-1.63), 2.06 (1.36-3.12), 1.93 (1.38-2.69) and 3.30 (1.13-9.67). Compared with chemotherapy alone, all differences were statistically significant. CIK cells could increase the CD3+ T cells, CD3+ CD4+ T cells, NK cells and the ratio of CD4+/CD8+ T cells. The chemotherapy with CIK cells had a lower risk of hematotoxicity, gastrointestinal toxicity, liver injury and a higher fever than that of chemotherapy alone. The evidence quality was "moderate" to "very low." CONCLUSIONS: The available moderate evidences indicate that chemotherapy with CIK cells, especially autologous CIK cells, can significantly improve the tumor responses, 1- and 2-year overall and progression-free survival rates in patients with advanced NSCLC. This treatment does have a high risk of fever. The optimal use may be treatment with one or two cycles and in combination with vinorelbine and cisplatin, paclitaxel and cisplatin, or docetaxel and cisplatin.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/terapia , Células Matadoras Induzidas por Citocinas/imunologia , Imunoterapia/efeitos adversos , Neoplasias Pulmonares/terapia , Ensaios Clínicos Controlados Aleatórios como Assunto , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Pulmonar de Células não Pequenas/imunologia , Carcinoma Pulmonar de Células não Pequenas/mortalidade , China , Feminino , Seguimentos , Humanos , Imunidade Celular , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/mortalidade , Masculino , Pessoa de Meia-Idade , Intervalo Livre de Progressão , Taxa de Sobrevida , Linfócitos T/imunologia , Adulto Jovem
10.
J Clin Pharm Ther ; 44(1): 23-38, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30229971

RESUMO

WHAT IS KNOWN AND OBJECTIVE: Sodium cantharidinate has been widely used in lung cancer treatment in China. To investigate whether sodium cantharidinate improves clinical effectiveness in non-small-cell lung cancer, we systematically re-evaluated all related studies. METHODS: All studies of cantharidinate for non-small-cell lung cancers (NSCLC) were selected from the MEDLINE, EMBASE, Web of Science (ISI), China National Knowledge Infrastructure Database (CNKI), Chinese Scientific Journals Full-Text Database (VIP), Wanfang, China Biological Medicine Database (CBM), Cochrane Central Register of Controlled Trials (CENTRAL), Chinese clinical trial registry (Chi-CTR), WHO International Clinical Trials Registry Platform (WHO-ICTRP) and US-clinical trials databases (established to September 2017). Their quality was evaluated using the Cochrane evaluation handbook of randomized controlled trials (RCTs) (5.1.0). The data were extracted following PICO principles and synthesized through meta-analysis. RESULTS AND DISCUSSION: We included 38 trials involving 2845 patients, but most trials had an unclear risk of bias. Sodium cantharidinate could increase the objective response rate (ORR) (1.52, (1.40-1.66]), disease control rate (DCR) (1.20, [1.16-1.25]) and quality of life (QOL) (1.76, [1.56-1.98]), but not the 1-year overall survival (OS) rate (1.16, [0.91-1.47]) and the 2-year OS rate (1.21, [0.51-2.91]). Subgroup analysis revealed that sodium cantharidinate and vitamin B6 at 0.5, 0.4 or 0.3 mg, and cantharidinate at 0.5 mg could all increase the ORR and DCR. Cantharidinate therapy had a lower risk of neutropenia (0.58, [0.50-0.67]), thrombocytopenia (0.57, [0.45-0.72]), gastrointestinal reaction (0.65, [0.52-0.82]) and nausea/vomiting (0.56, [0.41-0.76]) than that of chemotherapy alone. Sensitivity analysis showed that the results had good robustness. WHAT IS NEW AND CONCLUSION: Current evidence reveals that sodium cantharidinate can improve tumour responses and QOL with a lower risk of haematotoxicity and gastrointestinal toxicity than chemotherapy alone in NSCLC. However, the evidence does not indicate that it can improve long-term survival rates.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Cantaridina/administração & dosagem , Cantaridina/análogos & derivados , Carcinoma Pulmonar de Células não Pequenas/patologia , Humanos , Neoplasias Pulmonares/patologia , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Taxa de Sobrevida , Resultado do Tratamento
11.
Glob Chang Biol ; 23(3): 1338-1352, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27416519

RESUMO

Salinity intrusion caused by land subsidence resulting from increasing groundwater abstraction, decreasing river sediment loads and increasing sea level because of climate change has caused widespread soil salinization in coastal ecosystems. Soil salinization may greatly alter nitrogen (N) cycling in coastal ecosystems. However, a comprehensive understanding of the effects of soil salinization on ecosystem N pools, cycling processes and fluxes is not available for coastal ecosystems. Therefore, we compiled data from 551 observations from 21 peer-reviewed papers and conducted a meta-analysis of experimental soil salinization effects on 19 variables related to N pools, cycling processes and fluxes in coastal ecosystems. Our results showed that the effects of soil salinization varied across different ecosystem types and salinity levels. Soil salinization increased plant N content (18%), soil NH4+ (12%) and soil total N (210%), although it decreased soil NO3- (2%) and soil microbial biomass N (74%). Increasing soil salinity stimulated soil N2 O fluxes as well as hydrological NH4+ and NO2- fluxes more than threefold, although it decreased the hydrological dissolved organic nitrogen (DON) flux (59%). Soil salinization also increased the net N mineralization by 70%, although salinization effects were not observed on the net nitrification, denitrification and dissimilatory nitrate reduction to ammonium in this meta-analysis. Overall, this meta-analysis improves our understanding of the responses of ecosystem N cycling to soil salinization, identifies knowledge gaps and highlights the urgent need for studies on the effects of soil salinization on coastal agro-ecosystem and microbial N immobilization. Additional increases in knowledge are critical for designing sustainable adaptation measures to the predicted intrusion of salinity intrusion so that the productivity of coastal agro-ecosystems can be maintained or improved and the N losses and pollution of the natural environment can be minimized.


Assuntos
Mudança Climática , Ciclo do Nitrogênio , Solo , Ecossistema , Nitrificação , Nitrogênio , Áreas Alagadas
12.
Glob Chang Biol ; 23(10): 4068-4083, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28142211

RESUMO

Animal manure application as organic fertilizer does not only sustain agricultural productivity and increase soil organic carbon (SOC) stocks, but also affects soil nitrogen cycling and nitrous oxide (N2 O) emissions. However, given that the sign and magnitude of manure effects on soil N2 O emissions is uncertain, the net climatic impact of manure application in arable land is unknown. Here, we performed a global meta-analysis using field experimental data published in peer-reviewed journals prior to December 2015. In this meta-analysis, we quantified the responses of N2 O emissions to manure application relative to synthetic N fertilizer application from individual studies and analyzed manure characteristics, experimental duration, climate, and soil properties as explanatory factors. Manure application significantly increased N2 O emissions by an average 32.7% (95% confidence interval: 5.1-58.2%) compared to application of synthetic N fertilizer alone. The significant stimulation of N2 O emissions occurred following cattle and poultry manure applications, subsurface manure application, and raw manure application. Furthermore, the significant stimulatory effects on N2 O emissions were also observed for warm temperate climate, acid soils (pH < 6.5), and soil texture classes of sandy loam and clay loam. Average direct N2 O emission factors (EFs) of 1.87% and 0.24% were estimated for upland soils and rice paddy soils receiving manure application, respectively. Although manure application increased SOC stocks, our study suggested that the benefit of increasing SOC stocks as GHG sinks could be largely offset by stimulation of soil N2 O emissions and aggravated by CH4 emissions if, particularly for rice paddy soils, the stimulation of CH4 emissions by manure application was taken into account.


Assuntos
Agricultura , Ciclo do Carbono , Óxido Nitroso , Solo , Animais , Carbono , Bovinos , Fertilizantes , Esterco
13.
Rapid Commun Mass Spectrom ; 31(16): 1333-1343, 2017 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-28557104

RESUMO

RATIONALE: Chemodenitrification is an important N2 O source in soil; however, knowledge about the production of CO2 and N2 O from abiotic nitrite-SOM reactions, especially the N2 O isotopic signatures (intramolecular 15 N site preference (SP), and δ15 Nbulk and δ18 O values), is quite limited at present. METHODS: N2 O and CO2 emissions from chemical reactions of nitrite with lignin products were determined with gas chromatography, and their response surfaces as a function of pH from 3 to 6 and nitrite concentration from 0.1 to 0.5 mM were explored with polynomial regression. The intramolecular 15 N distribution of N2 O, as well as δ15 Nbulk and δ18 O values, were measured with an isotope ratio mass spectrometer coupled to an online pre-concentration unit. The variability in N2 O SP values was tested from pH 3 to 5, and for nitrite concentrations from 0.3 to 0.5 mM. RESULTS: Both CO2 and N2 O emissions varied largely with pH and the structure of lignin products. The highest N2 O emission occurred at pH 4-5 in 4-hydroxy-3,5-dimethoxybenzaldehyde and 4-hydroxy-3,5-dimethoxybenzoic acid treatments, and at pH 3 in the treatments with lignin, 4-hydroxy-3-methoxybenzaldehyde, 4-hydroxy-3-methoxybenzoic acid, 4-hydroxybenzaldehyde, and 4-hydroxybenzoic acid. A wide range of N2 O SP values (11.9-37.4‰), which was pH dependent and not distinguishable from microbial pathways, was observed at pH 3-5. The δ15 Nbulk and δ18 O values of N2 O were both in a similar range to that reported for fungal denitrification and bacterial denitrification. CONCLUSIONS: These results present the first characterization of the isotopic composition of N2 O from chemodenitrification in pure chemical assays. Chemical reactions of nitrite with lignin are pH-dependent and associated with substantial CO2 and N2 O emissions. The SP values of N2 O derived from chemodenitrification were neither distinguishable from the biotic pathways nor remained stable with varying pH. Therefore, the use of N2 O isotopic signatures for source partitioning is restricted when chemodenitrification is contributing significantly to N2 O emission.

14.
Zhongguo Zhong Yao Za Zhi ; 42(1): 146-151, 2017 Jan.
Artigo em Zh | MEDLINE | ID: mdl-28945040

RESUMO

To study the effect of ginseng saponin Rh2 in inducing apoptosis of human leukemia K562 cells, and explore its mechanism from the aspect of autophagy pathway. CCK-8 assay was used to examine the growth inhibition of human leukemia cell lines K562 treated with ginsenoside Rh2; flow cytometry (FCM) was used to detect cell apoptosis; Hoechst staining was used to observe the changes of cell morphological apoptosis; Acridine and MDC staining were used to detect the effects of the Rh2 on autophagy; Western blot and RT-PCR were used to detect the expression levels of the proteins closely associated with autophagy and apoptosis. In order to study the effect of autophagy in proliferation and apoptosis, we used the autophagy inhibitor (3-MA).CCK-8 indicated that Rh2 at low concentration could effectively inhibit the proliferation of leukemia cellsin dose- and time-dependent manners in K562 cells; FCM indicated that Rh2 induced apoptosis; Hoechest staining showed that K562 cells had typical apoptotic morphological changes by treated Rh2; Acridine and MDC staining showed that Rh2 enhanced the green fluorescence and a large number of acidic autophagy vesicles were present; Western blot and RT-PCR results showed that Rh2 increased the expression levels of Beclin-1, LC3A, LC3B, activated Caspase-3 and p-p38 in K562 cells; application of autophagy inhibitors(3-MA) could weaken the inhibition effect of Rh2 on proliferation and induction effect on apoptosis in K562 cells. Ginsenoside Rh2 inhibited the proliferation and induced apoptosis probably through activating p-p38, and inducing cell autophagy signaling pathway in K562 cells.


Assuntos
Apoptose , Autofagia , Ginsenosídeos/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Proliferação de Células , Humanos , Células K562
15.
Bioprocess Biosyst Eng ; 39(3): 511-9, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26747441

RESUMO

This work studied a cost-effective electrosorption that driven by microbial fuel cells (MFC-sorption) to remove Cu(2+) from wastewater without an external energy supply. The impact factors, adsorption isotherms and kinetics of the novel process were investigated. It indicated that a low electrolyte concentration and a high solution pH could enhance the Cu(2+) removal efficiency, while the adsorption capacity increased with the increase of numbers of MFCs in series and the initial Cu(2+) concentration. The adsorption isotherms study indicated that the monolayer adsorption in MFC-sorption was dominant. The kinetics study suggested the increase of initial Cu(2+) concentration could enhance the initial adsorption rate. The electrode characterizations verified the existence of Cu2O and Cu on the electrode surface of active carbon fibers (ACFs), suggesting that MFC-sorption was not only an adsorption process, but also a redox reaction process.


Assuntos
Fontes de Energia Bioelétrica , Cobre/química , Concentração de Íons de Hidrogênio , Cinética
16.
Biotechnol Lett ; 37(12): 2357-64, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26272393

RESUMO

Microbial fuel cells (MFCs) face major hurdles for real-world applications as power generators with the exception of powering small sensor devices. Despite tremendous improvements made in the last two decades, MFCs are still too expensive to build and operate and their power output is still too small. In view of this, in recently years, intensive researches have been carried out to expand the applications into other areas such as acid and alkali production, bioremediation of aquatic sediments, desalination and biosensors. Unlike power applications, MFC sensors have the immediate prospect to be practical. This review covers the latest developments in various proposed biosensor applications using MFCs including monitoring microbial activity, testing biochemical oxygen demand, detection of toxicants and detection of microbial biofilms that cause biocorrosion.


Assuntos
Fontes de Energia Bioelétrica , Técnicas Biossensoriais/métodos , Biotecnologia/métodos
17.
Bioprocess Biosyst Eng ; 37(5): 873-80, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24057921

RESUMO

A photosynthetic algal microbial fuel cell (PAMFC) was constructed by the introduction of immobilized microalgae (Chlorella vulgaris) into the cathode chamber of microbial fuel cells to fulfill electricity generation, biomass production and wastewater treatment. The immobilization conditions, including the concentration of immobilized matrix, initial inoculation concentration and cross-linking time, were investigated both for the growth of C. vulgaris and power generation. It performed the best at 5 % sodium alginate and 2 % calcium chloride as immobilization matrix, initial inoculation concentration of 10(6) cell/mL and cross-linking time of 4 h. Our findings indicated that C. vulgaris immobilization was an effective and promising approach to improve the performance of PAMFC, and after optimization the power density and Coulombic efficiency improved by 258 and 88.4 %, respectively. Important parameters such as temperature and light intensity were optimized on the performance. PAMFC could achieve a COD removal efficiency of 92.1 %, and simultaneously the maximum power density reached 2,572.8 mW/m(3) and the Coulombic efficiency was 14.1 %, under the light intensity of 5,000 lux and temperature at 25 °C.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Chlorella vulgaris/crescimento & desenvolvimento , Eletricidade , Águas Residuárias/microbiologia , Purificação da Água , Células Imobilizadas/metabolismo
18.
PLoS One ; 19(3): e0299988, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38442112

RESUMO

OBJECTIVE: To analyze the equity and efficiency of health resource allocation in township health centers in Sichuan Province, and to provide a scientific basis for promoting the development of township health centers in Sichuan Province, China. METHODS: The Lorenz curve, Gini coefficient and health resource density index were used to analyze the equity of health resource allocation in township health centers in Sichuan Province from 2017 to 2021, and data envelopment analysis(DEA) was used to analyze the efficiency of health resource allocation in township health centers in Sichuan Province from 2017 to 2021. RESULTS: The Gini coefficient of health resources of township health centers in Sichuan Province is below 0.2 by population in addition to the number of beds in 2020-2021 and practicing (assistant) physicians in 2021, and the Gini coefficient of health resources of township health centers in Sichuan Province is above 0.6 by geography. The Lorentz curve of health resources of township health centers in Sichuan Province is closer to the equity line by population allocation and further from the equity line by geographical allocation. The average level of township health centers in Sichuan Province is used as the standard to calculate the health resource density standard index(W) of each region, the Ws of Panzhihua, Ganzi, Aba and Liangshan are less than 1, and the Ws of Ziyang, Neijiang, Deyang and Meishan are greater than 1. The overall efficiency of township health centers in Sichuan Province in 2017 and 2021 is 1, and the DEA is relatively effective. The overall efficiency of township health centers in Sichuan Province in 2018 and 2019 is not 1, and the DEA is relatively ineffective. The overall efficiency of all health resources in Mianyang and Ziyang is 1, and the DEA is relatively effective. The overall efficiency of all health resources in Suining, Neijiang, Yibin, Aba and Ganzi is not 1, and the DEA is relatively ineffective. CONCLUSION: The equity of health resource allocation by population is better than that by geography in township health centers in Sichuan Province. Combining population and geographical factors, the health resource allocation of Panzhihua, Ganzi, Aba and Liangshan is lower than the average level of Sichuan Province. The efficiency of health resource allocation in township health centers in Sichuan Province is low.


Assuntos
Leitos , Análise de Dados , China , Recursos em Saúde , Alocação de Recursos
19.
BMJ Open ; 14(3): e082721, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38514148

RESUMO

OBJECTIVE: To analyse regional differences in health resource allocation in the Chengdu-Chongqing economic circle. DESIGN: A longitudinal analysis that collected data on health resource allocation from 2017 to 2021. SETTING: The number of beds, health technicians, licensed (assistant) physicians, registered nurses and financial allocations per 1000 population in the 42 regions of Chengdu-Chongqing economic circle were used for the analysis. METHODS: The entropy weight technique for order preference by similarity to an ideal solution (TOPSIS) method and the rank sum ratio (RSR) method were used to evaluate the health resource allocation. RESULTS: The number of licensed (assistant) physicians per 1000 population in the Chengdu-Chongqing economic circle (3.01) was lower than the average in China (3.04) in 2021. According to the entropy weight-TOPSIS method, Yuzhong in Chongqing had the largest C-value and the highest ranking. Jiangbei in Chongqing and Chengdu and Ya'an in Sichuan Province had higher C-values and were ranked in the top 10. Jiangjin, Hechuan, Tongnan and Zhongxian in Chongqing and Guang'an in Sichuan Province had lower C-values and were all ranked after the 30th place. According to the RSR method, the 42 regions were divided into three grades of good, medium and poor. The health resource allocations of Yuzhong, Jiangbei, Nanchuan, Jiulongpo and Shapingba in Chongqing and Chengdu and Ya'an in Sichuan Province were of good grade, those of Tongnan, Jiangjin, Yubei and Dazu in Chongqing and Guang'an and Dazhou in Sichuan Province were of poor grade, and the rest of the regions were of medium grade. CONCLUSION: The regional differences in health resource allocation in the Chengdu-Chongqing economic circle were more obvious, the health resource allocation in Chongqing was more polarised and the health resource allocation in Sichuan Province was more balanced, but the advantaged regions were not prominent enough.


Assuntos
Recursos em Saúde , Alocação de Recursos , Humanos , Estudos Longitudinais , China/epidemiologia , Coleta de Dados
20.
Risk Manag Healthc Policy ; 17: 341-353, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38384729

RESUMO

Objective: To analyze the equity of human resources allocation of the Centers for Disease Control and Prevention (CDCs) and to predict the development in the next five years in China, and to provide a scientific basis for promoting the development of human resources. Methods: The data of the CDCs from 2017 to 2021 were obtained from the "China Health Statistical Yearbook", and descriptive analysis, health resource density index (HRDI), Theil index, and health resource agglomeration degree (HRAD) were used to evaluate the equity, and the grey prediction model GM (1, 1) was used to predict the development from 2022 to 2026. Results: Measured by the HRDI, the shortage of human resources in the western region was relatively obvious, with a shortage of more than 11,656 health technicians, more than 6418 licensed (assistant) physicians, and more than 693 registered nurses. The Theil index of human resources allocation by population was between 0.016 and 0.071, and the Theil index of human resources allocation by geography was between 0.312 and 0.359. The allocation of human resources by geography was more unequal than those allocated by population. In terms of HRAD, human resources are over-allocated equitably by geography in the eastern and central regions, while they are under-allocated equitably by geography in the western region. In terms of the difference between the HRAD and PAD, the eastern region has a shortage of human resources relative to the concentration population, and the western region has an excess of human resources relative to the concentration population. Conclusion: The human resources allocation of the CDCs in China was uneven. The human resources of the CDCs were allocated more equitably by population than by geography. There was a situation where the equity of human resource allocation of the CDCs was contrary to the actual demand for medical care.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA