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1.
Int J Environ Health Res ; 24(1): 1-10, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-23427794

RESUMO

Understanding the influence of temperature on hand-foot-and-mouth disease (HFMD) is an important public health concern as well as being a major climate-infection issue in mainland China. City-scale data of incidence rates (IRs) of HFMD and temperature from 2008 to 2009 in mainland China has been analyzed. There were two peak periods for HFMD prevalence from April to July and August to November. Regions with higher monthly IR of HFMD periodically shifted following the pattern of south-north-south from March to December. Monthly IR of HFMD at city scale were closely associated with both average monthly temperature and monthly temperature range. Our study shows that spatiotemporal trends of HFMD infection were sensitive to temperature variation, and suggest that preventive measures should be considered for limiting the epidemic of HFMD in the cities with higher monthly IR during the peak periods.


Assuntos
Epidemias , Doença de Mão, Pé e Boca/epidemiologia , China/epidemiologia , Cidades , Enterovirus , Doença de Mão, Pé e Boca/virologia , Humanos , Incidência , Prevalência , Estações do Ano , Temperatura
2.
Bioresour Technol ; 399: 130518, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38432544

RESUMO

This study identified the intrinsic relationships among slurry rheology, particle characteristics, and lignocellulosic liquefaction/saccharification based on correlation analysis and principal component analysis during the hydrolysis of sugarcane bagasse pretreated by deep eutectic solvents (DES) and mechanical milling (MM). The DES-MM pretreated lignocellulosic slurry (20% solids) exhibited high apparent viscosity of 1.4 × 104 Pa·s and shear stress of 929.0 Pa under steady state. Glucose production had a negative linear correlation with slurry viscosity (R2, 0.69-0.97), whereas its correlation with yield stress (R2, 0.85-0.98) depended on the particle liquefaction rate. The availability of free water provided a major contribution to improving slurry rheology. However, the size reduction of submillimeter particles and the changes in particle hydrophilicity during liquefaction were not significantly correlated with rheological changes. Various interrelated particle characteristics and rheological changes were integrated into two simple principal variables to predict glucose production with a high R2 of 0.96.


Assuntos
Celulase , Saccharum , Celulose , Hidrólise , Glucose , Reologia
3.
Bioresour Technol ; 344(Pt B): 126264, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34737053

RESUMO

The complex structure of lignocellulosic biomass forms the recalcitrance to prevent the embedded holo-cellulosic sugars from undergoing the biodegradation. Therefore, a pretreatment is often required for an efficient enzymatic lignocellulosic hydrolysis. Recently, glycerol organosolv (GO) pretreatment is revealed potent in selective deconstruction of various lignocellulosic biomass and effective improvement of enzymatic hydrolysis. Evidently, the GO pretreatment is capable to modify the structure of dissolved components by glycerolysis, i.e., by trans-glycosylation onto glyceryl glycosides and by hydroxylation grafting onto glyceryl lignin. Such modifications tend to protect these main components against excessive degradation, which can be mainly responsible for the obviously less fermentation inhibitors arising in the GO pretreatment. This pretreatment can provide opportunities for valorization of emerging lignocellulosic biorefinery with production of value-added biochemicals. Recent advances in GO pretreatment of lignocellulosic biomass followed by enzymatic hydrolysis are reviewed, and perspectives are made for addressing remaining challenges.


Assuntos
Glicerol , Açúcares , Biomassa , Hidrólise , Lignina
4.
Bioresour Technol ; 338: 125505, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34273627

RESUMO

The acquisition during biomass saccharification of elevated levels of fermentable sugars with lower cellulase concentration is central to ensuring an economically viable and industrially relevant hydrolytic process. Thus, using a new cellulase preparation (LT4) at low cellulase loading (2 mg protein/g dried substrate), this study assessed the possible boosting effect of integrating accessory enzymes and additives on high-solids hydrolysis of sugarcane bagasse via fed-batch feeding. Hydrolysis which commenced with initial 8% solids loading and subsequent substrate feeding of 4% solids at 6 h, 18 h, and 24 h respectively, proved optimal for the 20% high-solids saccharification producing 158 g/L total sugars and 83% glucose yield after 72 h with the combined optimized additives and accessory enzymes. The results obtained indicate that the integration of accessory enzymes and additives offers a benignant approach to minimizing the enzyme load and cost of high solids saccharification of lignocellulosic heteropolymers while also boosting enzyme hydrolytic performance.


Assuntos
Celulase , Saccharum , Álcalis , Catálise , Celulose , Digestão , Glicerol , Hidrólise
5.
Environ Health Perspect ; 126(4): 047010, 2018 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-29681142

RESUMO

BACKGROUND: There is limited evidence about the association between ambient temperature and the incidence of pediatric hand, foot, and mouth disease (HFMD) nationwide in China. OBJECTIVES: We examined the childhood temperature-HFMD associations across mainland China, and we projected the change in HFMD cases due to projected temperature change by the 2090s. METHODS: Data on daily HFMD (children 0-14 y old) counts and weather were collected from 362 sites during 2009-2014. Daily temperature by the 2090s was downscaled under the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. Temperature-HFMD associations were quantified using a two-stage Poisson regression with a distributed lag nonlinear model. The impact of changes in temperature on the incidence of HFMD was estimated by combining the fitted temperature-HFMD associations with projected temperatures under each scenario, assuming a constant population structure. Sensitivity analyses were performed to assess the influence of primary model assumptions. RESULTS: During 2009-2014, >11 million HFMD cases were reported. In most regions, the temperature-HFMD association had an inverted U shape with a peak at approximately 20°C, but the association leveled off or continued to increase in the Inner Mongolia and Northeast regions. When estimates were pooled across all regions and the population size was held constant, the projected incidence of HFMD increased by 3.2% [95% empirical confidence interval (eCI): −13.5%, 20.0%] and 5.3% (95% eCI: −33.3%, 44.0%) by the 2090s under the RCP 4.5 and 8.5 scenarios, respectively. However, regional projections suggest that HFMD may decrease with climate change in temperate areas of central and eastern China. CONCLUSION: Our estimates suggest that the association between temperature and HFMD varies across China and that the future impact of climate change on HFMD incidence will vary as well. Other factors, including changes in the size of the population at risk (children 0-14 y old) will also influence future HFMD trends. https://doi.org/10.1289/EHP3062.


Assuntos
Mudança Climática , Doença de Mão, Pé e Boca/epidemiologia , Temperatura , Adolescente , Criança , Pré-Escolar , China/epidemiologia , Previsões , Humanos , Incidência , Lactente , Recém-Nascido , Modelos Teóricos
6.
Bioresour Technol ; 193: 234-42, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26141283

RESUMO

The anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor (AnMBR) was investigated at two different operational modes, including no sludge discharge and daily sludge discharge of 20 L. The AnMBR provided excellent and reliable permeate quality with high COD removal efficiencies over 99%. The obvious accumulations of long chain fatty acids (LCFAs) and Ca(2+) were found in the anaerobic digester by precipitation and agglomeration. Though the physicochemical process contributed to attenuating the free LCFAs toxicity on anaerobic digestion, the digestion efficiency was partly influenced for the low bioavailability of those precipitates. Moreover, higher organic loading rate (OLR) of 5.8 kg COD/(m(3) d) and digestion efficiency of 78% were achieved as the AnMBR was stably operated with sludge discharge, where the membrane fouling propensity was also alleviated, indicating the crucial significance of SRT control on the treatment of high-strength kitchen waste slurry via AnMBRs.


Assuntos
Filtração/instrumentação , Esgotos/química , Eliminação de Resíduos Líquidos/instrumentação , Águas Residuárias/química , Purificação da Água/instrumentação , Anaerobiose , Reatores Biológicos , Filtração/métodos , Membranas Artificiais , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos
7.
PLoS One ; 3(11): e3777, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19020664

RESUMO

BACKGROUND: Paper pulp wastewater resulting from alkaline extraction of wheat straw, known as black liquor, is very difficult to be treated and causes serious environmental problems due to its high pH value and chemical oxygen demand (COD) pollution load. Lignin, semicellulose and cellulose are the main contributors to the high COD values in black liquor. Very few microorganisms can survive in such harsh environments of the alkaline wheat straw black liquor. A naturally developed microbial community was found accidentally in a black liquor storing pool in a paper pulp mill of China. The community was effective in pH decreasing, color and COD removing from the high alkaline and high COD black liquor. FINDINGS: Thirty-eight strains of bacteria were isolated from the black liquor storing pool, and were grouped as eleven operational taxonomy units (OTUs) using random amplified polymorphic DNA-PCR profiles (RAPD). Eleven representative strains of each OTU, which were identified as genera of Halomonas and Bacillus, were used to construct a consortium to treat black liquor with a high pH value of 11.0 and very high COD pollution load of 142,600 mg l(-1). After treatment by the constructed consortium, about 35.4% of color and 39,000 mg l(-1) (27.3%) COD(cr) were removed and the pH decreased to 7.8. 16S rRNA gene polymerase chain reaction denaturant gradient gel electrophoresis (PCR-DGGE) and gas chromatography/mass spectrometry (GC/MS) analysis suggested a two-stage treatment mechanism to elucidate the interspecies collaboration: Halomonas isolates were important in the first stage to produce organic acids that contributed to the pH decline, while Bacillus isolates were involved in the degradation of lignin derivatives in the second stage under lower pH conditions. CONCLUSIONS/SIGNIFICANCE: Tolerance to the high alkaline environment and good controllability of the simple consortium suggested that the constructed consortium has good potential for black liquor treatment. Facilitating the treatment process by the constructed consortium would provide a promising opportunity to reduce the pollution, as well as to save forest resources and add value to a waste product.


Assuntos
Recuperação e Remediação Ambiental/métodos , Poluentes Químicos da Água/análise , Bacillus/metabolismo , Benzaldeídos/química , Celulose/química , China , Meio Ambiente , Recuperação e Remediação Ambiental/instrumentação , Concentração de Íons de Hidrogênio , Resíduos Industriais , Lignina/química , Oxigênio/química , Filogenia , RNA Ribossômico 16S/química , Eliminação de Resíduos Líquidos/métodos , Abastecimento de Água
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