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1.
J Med Virol ; 95(8): e29030, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37565734

RESUMO

Enterovirus A71 (EV-A71) is a highly contagious virus that poses a major threat to global health, representing the primary etiological agent for hand-foot and mouth disease (HFMD) and neurological complications. It has been established that interferon signaling is critical to establishing a robust antiviral state in host cells, mainly mediated through the antiviral effects of numerous interferon-stimulated genes (ISGs). The host restriction factor SHFL is a novel ISG with broad antiviral activity against various viruses through diverse underlying molecular mechanisms. Although SHFL is widely acknowledged for its broad-spectrum antiviral activity, it remains elusive whether SHFL inhibits EV-A71. In this work, we validated that EV-A71 triggers the upregulation of SHFL both in cell lines and in a mouse model. Knockdown and overexpression of SHFL in EVA71-infected cells suggested that this factor could markedly suppress EV-A71 replication. Our findings further revealed an intriguing mechanism of SHFL that it could interact with the nonstructural proteins 3Dpol of EV-A71 and promoted the degradation of 3Dpol through the ubiquitin-proteasome pathway. Furthermore, the zinc-finger domain and the 36 amino acids (164-199) of SHFL were crucial to the interaction between SHFL and EV-A71 3Dpol . Overall, these findings broadened our understanding of the pivotal roles of SHFL in the interaction between the host and EV-A71.


Assuntos
Enterovirus Humano A , Infecções por Enterovirus , Enterovirus , Doença de Mão, Pé e Boca , Animais , Camundongos , Enterovirus Humano A/genética , Complexo de Endopeptidases do Proteassoma , Produtos do Gene pol , Antígenos Virais/genética , Antivirais , Interferons , Ubiquitinas
2.
Environ Sci Technol ; 55(2): 1178-1189, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33403849

RESUMO

Microalgae is a promising candidate for reducing greenhouse gas and producing renewable biofuels. For microalgae biofilm cultivation, a strong adhesion ability of microalgae cells onto the surface is a prerequisite to resist the fluid shear stress, while strong adhesion is not of benefit to the biofilm harvesting process. To solve this dilemma, a thermoresponsive surface (TMRS) with lower critical solution temperature of 33 °C was made by grafting N-isopropylacrylamide onto a silicate glass slide. The wettability of the TMRS changed from hydrophilic (contact angle of 59.4°) to hydrophobic (contact angle of 91.6°) when the temperature rose from 15 to 35 °C, resulting in the increase of adhesion energy of the TMRS to Chlorella vulgaris cells by 135.6%. The experiments showed that the cells were more likely to attach onto the TMRS at the higher temperature of 35 °C owing to the surface microstructures generated by the hydrogel layer shrinkage, which is similar in size to the microalgae cells. And the cell coverage rate on TMRS increased by 32% compared to the original glass surface. Conversely, the cells separate easily from the TMRS at a lower temperature of 15 °C, and the cell adhesion density was reduced by 19% due to hydrogel layer swelling to a relatively flat surface.


Assuntos
Chlorella vulgaris , Microalgas , Acrilamidas , Resinas Acrílicas , Biofilmes , Adesão Celular , Hidrogéis , Propriedades de Superfície , Temperatura
3.
Appl Opt ; 54(2): 228-35, 2015 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-25967621

RESUMO

A fiber-optic differential absorption sensor was developed to accurately monitor biomass growth in a photobioreactor. The prepared sensor consists of two probes: the sensor and the reference. The sensor probe was employed to monitor the biomass and changes in the liquid-phase concentration in a culture. To separate the liquids from photosynthetic bacteria CQK 01 and measure the liquid-phase concentration, a proposed polyimide-silica hybrid membrane was coated on the sensing region of the reference probe. A linear relationship was observed between the sensor output signal and the biomass from the lag phase to the decline phase.


Assuntos
Bactérias/química , Biomassa , Tecnologia de Fibra Óptica , Dispositivos Ópticos , Fotobiorreatores , Desenho de Equipamento , Imidas/química , Membranas Artificiais , Fibras Ópticas , Fotossíntese , Dióxido de Silício/química
4.
Anal Chem ; 86(18): 9278-85, 2014 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-25166743

RESUMO

A microstructured fiber Bragg grating (MSFBG) was created to accurately and simultaneously monitor the cell growth of photosynthetic bacteria (PSB) Rhodopseudomonas palustris CQK 01 and the temperature in a photobioreactor. The proposed sensor was made from an FBG unit that was separated into three regions, an unperturbed region, and two etched regions with smooth surfaces. The unperturbed grating region was employed to monitor the temperature. To eliminate the effects of the liquid concentration and temperature on the biomass, a polyimide-silica hybrid membrane was created and coated on an etched grating region to separate the liquids from the PSB; that is, this thinned region was developed to analyze the liquid concentration and temperature. Another etched grating region with a smaller diameter was used to determine the response to the temperature, biomass, and liquid concentration. In addition, two models were also presented to demonstrate accurate simultaneous measurement of the biomass and temperature. We discovered that the MSFBG sensor can rapidly and accurately determine the difference in the Bragg wavelength shifts caused by changes in the temperature, biomass, and liquid-phase concentration. The measured biomass is highly correlated with the real cell growth, with a correlation of 0.9438; the hydrogen production rate and temperature difference from metabolic heat production reached 1.97 mmol/L/h and 2.8 °C, respectively, in the PSB culture.


Assuntos
Membranas Artificiais , Fotobiorreatores , Resinas Sintéticas/química , Rodopseudomonas/crescimento & desenvolvimento , Dióxido de Silício/química , Biomassa , Hidrogênio/metabolismo , Luz , Temperatura
5.
Anal Chem ; 86(8): 3994-4001, 2014 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-24697651

RESUMO

A new simple fiber-optic evanescent wave sensor was created to accurately monitor the growth and hydrogen production performance of biofilms. The proposed sensor consists of two probes (i.e., a sensor and reference probe), using the etched fibers with an appropriate surface roughness to improve its sensitivity. The sensor probe measures the biofilm growth and change of liquid-phase concentration inside the biofilm. The reference probe is coated with a hydrophilic polytetrafluoroethylene membrane to separate the liquids from photosynthetic bacteria Rhodopseudomonas palustris CQK 01 and to measure the liquid concentration. We also developed a model to demonstrate the accuracy of the measurement. The biofilm measurement was calibrated using an Olympus microscope. A linear relationship was obtained for the biofilm thickness range from 0 to 120 µm with a synthetic medium under continuous supply to the bioreactor. The highest level of hydrogen production rate occurred at a thickness of 115 µm.


Assuntos
Biofilmes/crescimento & desenvolvimento , Reatores Biológicos/microbiologia , Hidrogênio/química , Algoritmos , Técnicas Biossensoriais , Tecnologia de Fibra Óptica , Membranas Artificiais , Rodopseudomonas , Biologia Sintética
6.
ScientificWorldJournal ; 2014: 721620, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24977219

RESUMO

An experimental study was carried out to investigate the effects of inlet pressure, sample thickness, initial sample temperature, and temperature sensor location on the surface heat flux, surface temperature, and surface ultrafast cooling rate using stainless steel samples of diameter 27 mm and thickness (mm) 8.5, 13, 17.5, and 22, respectively. Inlet pressure was varied from 0.2 MPa to 1.8 MPa, while sample initial temperature varied from 600°C to 900°C. Beck's sequential function specification method was utilized to estimate surface heat flux and surface temperature. Inlet pressure has a positive effect on surface heat flux (SHF) within a critical value of pressure. Thickness of the sample affects the maximum achieved SHF negatively. Surface heat flux as high as 0.4024 MW/m(2) was estimated for a thickness of 8.5 mm. Insulation effects of vapor film become apparent in the sample initial temperature range of 900°C causing reduction in surface heat flux and cooling rate of the sample. A sensor location near to quenched surface is found to be a better choice to visualize the effects of spray parameters on surface heat flux and surface temperature. Cooling rate showed a profound increase for an inlet pressure of 0.8 MPa.


Assuntos
Transferência de Energia , Gases/química , Calefação/métodos , Modelos Teóricos , Aço Inoxidável/química , Água/química , Simulação por Computador , Teste de Materiais , Pressão , Temperatura , Condutividade Térmica
7.
Bioresour Technol ; 374: 128775, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36828216

RESUMO

Gentle and effective pretreatment is necessary to produce clean lignocellulosic biomass-based fuels. Herein, inspired by the efficient lignin degradation in the foregut of termites, the microreactor system using immobilized laccase and recoverable vanillin was proposed. Firstly, the co-deposition coating of dopamine, hydrogen peroxide and copper sulfate was constructed for laccase immobilization and a high immobilization efficiency of 87.0% was obtained in 30 min. After storage for 10 days, 82.2% activity was maintained in the laccase-loaded microreactor, which is 210.0% higher than free laccase. In addition, 6% (w/w) vanillin can improve lignin degradation in the laccase-loaded microreactor without impairing laccase activity, leading to a 47.3% increment in cellulose accessibility. Finally, a high cellulose conversion rate of 88.1% can be achieved in 1 h with glucose productivity of 2.62 g L-1 h-1. These demonstrated that the appropriate addition of vanillin can synergize with immobilized laccase to enhance the conversion of lignocellulosic biomass.


Assuntos
Lacase , Lignina , Lignina/metabolismo , Lacase/metabolismo , Biomassa , Celulose
8.
Bioresour Technol ; 359: 127475, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35714782

RESUMO

Hydrothermal pretreatment with diluted acid or alkali can disrupt the compact structure of wheat straw at a moderate temperature for efficient enzymatic saccharification. However, the quantitative analysis between the physicochemical properties and enzymatic hydrolyzability of hydrothermal pretreated lignocellulose was rarely investigated, which hindered the development of model-based applications for process design and control. Herein, correlation analysis (CA) and principal component analysis (PCA) were conducted to elucidate the dominant factors affecting the enzymatic hydrolyzability and quantitative relationship between them. CA results suggested the major positive factor affecting carbohydrate conversion was cellulose content (r = 0.86). Through logarithmic processing and linear combination, these intercorrelated factors were successfully converted into two newly uncorrelated variables named the first principal component (PC1) and the second principal component (PC2). The initial hydrolysis rate and carbohydrate conversion can be well predicted by PC1 and PC2 scores through multiple linear regression with a high R-squared (0.91 and 0.80).


Assuntos
Lignina , Triticum , Carboidratos , Celulose/química , Hidrólise , Lignina/química , Temperatura , Triticum/química
9.
Biosens Bioelectron ; 198: 113833, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34844169

RESUMO

To meet the emerging power demand of microelectronic and electronic skin based sensing platform, enzymatic fuel cells have received increasing attention due to their good human's compatibility, easy integration and cost effectiveness. Herein, we use multi-walled carbon nanotube/naphthoquinone to modify the lactate oxidase bio-anode to facilitate the electron transfer between electrocatalytic active site and electrode support. Polyvinyl alcohol hydrogel serves as the separator and lactate container. The bio-anode, Pt/C cathode and hydrogel are assembled in layer-by-layer structure, which can successfully utilize pre-stored and external lactate from human's sweat to generate the electricity. It delivers a power-density of 62.2 ± 2.4 µW cm-2 under bending/torsion conditions. Given that the broad substrate scope in sweat and easily assembled structure, it provides a plausible solution to power the miniaturized sensors and generic circuits.


Assuntos
Fontes de Energia Bioelétrica , Técnicas Biossensoriais , Naftoquinonas , Eletrodos , Eletrólitos , Humanos , Álcool de Polivinil
10.
Bioresour Technol ; 347: 126436, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34848331

RESUMO

The conversion of cellulose to platform chemicals has attracted much attention because of its renewability. This work proposed an earth-abundant cobalt disulfide as a heterogeneous catalyst for methyl levulinate production from cellulose. The highest yield of methyl levulinate reached 61 mol% under the tested conditions of 200 °C, 2 MPa initial pressure, 0.45 catalyst/cellulose mass ratio, and 3 h reaction time. The XRD and TEM analyses demonstrated the crystal facet (111) of cobalt disulfide as a robust active site, which was in good agreement with the highest acidity of the crystal facet (111) calculated by the work functions. The XPS characterization showed that the main chemical valence of cobalt disulfide responsible for the methyl levulinate production was the surface Co2+ species. This study is valuable for the development of a recoverable catalyst for the cellulose to methyl levulinate process.


Assuntos
Celulose , Ácidos Levulínicos , Catálise , Cobalto , Dissulfetos
11.
Atten Percept Psychophys ; 83(5): 2159-2173, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33759116

RESUMO

A critical question, fundamental for building models of emotion, is how to categorize emotions. Previous studies have typically taken one of two approaches: (a) they focused on the pre-perceptual visual cues, how salient facial features or configurations were displayed; or (b) they focused on the post-perceptual affective experiences, how emotions affected behavior. In this study, we attempted to group emotions at a peri-perceptual processing level: it is well known that humans perceive different facial expressions differently, therefore, can we classify facial expressions into distinct categories in terms of their perceptual similarities? Here, using a novel non-lexical paradigm, we assessed the perceptual dissimilarities between 20 facial expressions using reaction times. Multidimensional-scaling analysis revealed that facial expressions were organized predominantly along the upper-lower face axis. Cluster analysis of behavioral data delineated three superordinate categories, and eye-tracking measurements validated these clustering results. Interestingly, these superordinate categories can be conceptualized according to how facial displays interact with acoustic communications: One group comprises expressions that have salient mouth features. They likely link to species-specific vocalization, for example, crying, laughing. The second group comprises visual displays with diagnosing features in both the mouth and the eye regions. They are not directly articulable but can be expressed prosodically, for example, sad, angry. Expressions in the third group are also whole-face expressions but are completely independent of vocalization, and likely being blends of two or more elementary expressions. We propose a theoretical framework to interpret the tripartite division in which distinct expression subsets are interpreted as successive phases in an evolutionary chain.


Assuntos
Emoções , Expressão Facial , Face , Humanos , Estimulação Luminosa , Tempo de Reação
12.
Arch Public Health ; 79(1): 54, 2021 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-33892784

RESUMO

BACKGROUND: Although several measures have been taken to control hand foot and mouth disease (HFMD) and herpangina (HA), these two diseases have been prevalent in China for 10 years with high incidence. We suspected that adults' inapparent infection might be the cause of the continued prevalence of HFMD/HA infection in mainland China. METHODS: To explore the role of adults (especially caregivers) in the transmission process of HFMD/HA among children, 330 HFMD/HA cases and 330 healthy children (controls) were selected for a case-control study. Then, data were analyzed by logistic regression. RESULTS: Single-variable analyses revealed that caregivers who tested positive for enterovirus was a significant risk factor of HFMD/HA transmission to children (adjusted odds ratio (OR) = 9.22; 95% CI, 1.16 to 73.23). In the final multivariable model, caregiver behavior, such as cooling children's food with mouth (OR = 1.85; 95% CI, 1.11 to 3.08) and feeding children with their own tableware (OR = 2.19; 95% CI, 1.07 to 4.45), significantly increased the risk of transmitting HFMD/HA to children. On the contrary, washing hands before feeding children reduced such risk. CONCLUSIONS: These results implied that the caregivers might be the infectious source or carriers of enterovirus. Therefore, preventing or treating the caregivers' enterovirus infection and improving their hygiene habits, especially when they are in contact with children, could provide a breakthrough for the effective control of HFMD/HA.

13.
Am J Trop Med Hyg ; 103(5): 2091-2099, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32748774

RESUMO

Hand, foot, and mouth disease (HFMD) has brought millions of attacks and a substantial burden in the Asia-Pacific region. Previous studies assessed disease risks around the world, which demonstrated great heterogeneity, and few determined the modification effect of social factors on temperature-disease relationship. We conducted a time-series study to evaluate the temperature-associated HFMD morbidity risk using daily data (from 2011 to 2017) and to identify potential modifiers relating to urban-rural status and aggregation mode of children. By applying a distributed lag nonlinear model (DLNM) and controlling for time-varying factors and other meteorological factors, we found that the relationship between daily mean temperature and the cumulative risk of HFMD was an approximately M-shaped curve. The effects of higher temperature appeared to be greater and more persistent than those of lower temperature. With the reference of -6°C, the cumulative relative risk (RR) values of high temperature (95 percentile) and low temperature (5 percentile) were 3.74 (95% CI: 2.50-5.61) and 1.72 (95% CI: 1.24-2.37) at lag 4-7, respectively. Temperature-associated HFMD morbidity risks were more pronounced among rural children and those attending kindergartens or schools at specific lags and temperatures. Relative risk values for temperature-disease association was highest among the 3- to 6-year group, whereas no gender difference was observed. Studying effect estimates and their modifications using the DLNM on a daily scale helps to identify susceptible groups and guide policy-making and resource allocation according to specific local conditions.


Assuntos
Doença de Mão, Pé e Boca/epidemiologia , Temperatura , Criança , Pré-Escolar , China/epidemiologia , Monitoramento Epidemiológico , Feminino , Doença de Mão, Pé e Boca/virologia , Humanos , Lactente , Masculino , Conceitos Meteorológicos , Dinâmica não Linear , Risco , População Rural , População Urbana
14.
Bioresour Technol ; 307: 123192, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32220819

RESUMO

This study investigated the interactions between volatile and char during biomass pyrolysis at 400 °C, employing a ß-5 lignin dimer and amino-modified graphitized carbon nanotube (CNT-NH2) as their models, respectively. The results demonstrated that both -NH2 and its carrier (CNT) facilitated the conversion of the ß-5 dimer, which significantly increased from 9.7% (blank run), to 61.6% (with CNT), and to 96.6% (with CNT-NH2). CNT mainly favored the breakage of C-O bond in the feedstock to produce dimers with a yield of 55.5%, while CNT-NH2 promoted the cleavage of both C-O and C-C bonds to yield monomers with a yield up to 63.4%. Such significant changes in the pyrolysis behaviors of the ß-5 lignin dimer after the introduction of CNT-NH2 were considered to be mainly caused by hydrogen-bond formations between -NH2 and the dimeric feedstock/products, in addition to the π-π stacking between CNT and aromatic rings.


Assuntos
Lignina , Nanotubos de Carbono , Biomassa , Carvão Vegetal , Temperatura Alta , Pirólise
15.
Mol Plant ; 13(2): 336-350, 2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-31838037

RESUMO

The rubber tree, Hevea brasiliensis, produces natural rubber that serves as an essential industrial raw material. Here, we present a high-quality reference genome for a rubber tree cultivar GT1 using single-molecule real-time sequencing (SMRT) and Hi-C technologies to anchor the ∼1.47-Gb genome assembly into 18 pseudochromosomes. The chromosome-based genome analysis enabled us to establish a model of spurge chromosome evolution, since the common paleopolyploid event occurred before the split of Hevea and Manihot. We show recent and rapid bursts of the three Hevea-specific LTR-retrotransposon families during the last 10 million years, leading to the massive expansion by ∼65.88% (∼970 Mbp) of the whole rubber tree genome since the divergence from Manihot. We identify large-scale expansion of genes associated with whole rubber biosynthesis processes, such as basal metabolic processes, ethylene biosynthesis, and the activation of polysaccharide and glycoprotein lectin, which are important properties for latex production. A map of genomic variation between the cultivated and wild rubber trees was obtained, which contains ∼15.7 million high-quality single-nucleotide polymorphisms. We identified hundreds of candidate domestication genes with drastically lowered genomic diversity in the cultivated but not wild rubber trees despite a relatively short domestication history of rubber tree, some of which are involved in rubber biosynthesis. This genome assembly represents key resources for future rubber tree research and breeding, providing novel targets for improving plant biotic and abiotic tolerance and rubber production.


Assuntos
Cromossomos de Plantas/genética , Evolução Molecular , Genoma de Planta/genética , Hevea/genética , Borracha/metabolismo , Mapeamento Cromossômico , Domesticação , Euphorbia/classificação , Euphorbia/genética , Euphorbia/metabolismo , Hevea/classificação , Hevea/metabolismo , Família Multigênica , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Retroelementos , Tetraploidia
16.
Bioresour Technol ; 293: 122056, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31514117

RESUMO

Aiming at optimizing the adsorption process of Chlorella vulgaris and cationic starch, the adsorption thermodynamic characteristics were evaluated. Different from inorganic calcium salt adsorbent, the adsorption nature of organic polymer cationic starch is exothermic (ΔH°â€¯< 0) and spontaneous (ΔG°â€¯< 0). Besides, the adsorption capacity and rate can be well described by Langmiur isotherm and pseudo second kinetic models. As results of exothermic nature and great driving force of lower temperature, the adsorption capacity and rate declined with the rising temperature. The maximal values of them were obtained at 278.15 K, which were 9148.14 mg microalgae (g cationic starch)-1 and 8.74 × 10-6 mg g-1 min-1. Additionally, with insufficient adsorbent, the highest adsorption efficiency (96.37%) was achieved at 278.15 K for stirring 150 min. For 288.15, 298.15, 308.15 and 318.15 K, the adsorption efficiency decreased to 93.77%, 86.75%, 83.32% and 81.57% and the time consumed were at least 40 min longer.


Assuntos
Chlorella vulgaris , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Polímeros , Amido , Temperatura , Termodinâmica
17.
Bioresour Technol ; 244(Pt 1): 198-205, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28779672

RESUMO

Microalgae cells release O2 during photosynthesis. The gas can accumulate and adhere in form of bubbles, which affect the transport of nutrients in the biofilm and the biofilm microstructure. To investigate the reasons for the adhesion of these oxygen bubbles and their impact on biofilm, polytetrafluoroethylene (PTFE) emulsion was sprayed onto glass surface to change the parameters for gas accumulation and adhesion. The results indicated gas could aggregate into bubbles and adhere to hydrophobic and rough surface. The bubble behaviors caused the biofilm to be porous (with a microporosity of 9.43-20.94%). The biomass concentration of the more porous biofilm increased by 9.26% to 22.42gm-2 on 1% PTFE-treated surface compared to that on an untreated surface. However, with an increase in PTFE concentration, the amount of adhered bubbles increased. More microalgae cells in biofilms were carried up by bubbles. The biofilm concentration on 5% PTFE-treated surface decreased by 15.30%.


Assuntos
Biofilmes , Fotossíntese , Scenedesmus , Oxigênio , Politetrafluoretileno
18.
Artigo em Inglês | MEDLINE | ID: mdl-28335535

RESUMO

A hand-foot-mouth disease outbreak occurred in 2014 around Guangdong. The purpose of this study was investigating the status and susceptibility of infectious neutralizing antibodies to enterovirus 71 among children so as to provide scientific evidence for the population immunity level of hand-foot-mouth disease and prepare for enterovirus 71 vaccination implementation. Serum specimens were collected from children in communities from January 2014 to March 2015 in Guangzhou. A total of 197 serum samples from children 1-5 years old were collected for this cross-sectional study via non-probabilistic sampling from the database of Chinese National Science and Technique Major Project. Neutralization activity was measured via micro neutralization test in vitro. The positive rate of enterovirus 71 neutralizing antibodies was 59.4%, whereas the geometric mean titre was 1:12.7. A statistically significant difference in true positive rates was found between different age groups but not between different genders. Being the most susceptible population of hand-foot-mouth disease, children under 3 years of age are more likely to be infected with enterovirus 71, and the immunity of children increases with increasing age. Further cohort studies should be conducted, and measures for prevention and vaccination should be taken.


Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Enterovirus Humano A/imunologia , Doença de Mão, Pé e Boca/epidemiologia , Doença de Mão, Pé e Boca/imunologia , Biomarcadores/sangue , Pré-Escolar , China/epidemiologia , Estudos Transversais , Surtos de Doenças , Feminino , Doença de Mão, Pé e Boca/sangue , Doença de Mão, Pé e Boca/prevenção & controle , Humanos , Lactente , Masculino , Estudos Soroepidemiológicos , Vacinas Virais
19.
J Biomed Mater Res A ; 77(1): 103-11, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16392139

RESUMO

The ideal biomaterial for the repair of bone defects is expected to have good mechanical properties, be fabricated easily into a desired shape, support cell attachment, allow controlled release of bioactive factors to induce bone formation, and biodegrade into nontoxic products to permit natural bone formation and remodeling. The synthetic polymer poly(propylene fumarate) (PPF) holds great promise as such a biomaterial. In previous work we developed poly(DL-lactic-co-glycolic acid) (PLGA) and PPF microspheres for the controlled delivery of bioactive molecules. This study presents an approach to incorporate these microspheres into an injectable, porous PPF scaffold. Model drug Texas red dextran (TRD) was encapsulated into biodegradable PLGA and PPF microspheres at 2 microg/mg microsphere. Five porous composite formulations were fabricated via a gas foaming technique by combining the injectable PPF paste with the PLGA or PPF microspheres at 100 or 250 mg microsphere per composite formulation, or a control aqueous TRD solution (200 microg per composite). All scaffolds had an interconnected pore network with an average porosity of 64.8 +/- 3.6%. The presence of microspheres in the composite scaffolds was confirmed by scanning electron microscopy and confocal microscopy. The composite scaffolds exhibited a sustained release of the model drug for at least 28 days and had minimal burst release during the initial phase of release, as compared to drug release from microspheres alone. The compressive moduli of the scaffolds were between 2.4 and 26.2 MPa after fabrication, and between 14.9 and 62.8 MPa after 28 days in PBS. The scaffolds containing PPF microspheres exhibited a significantly higher initial compressive modulus than those containing PLGA microspheres. Increasing the amount of microspheres in the composites was found to significantly decrease the initial compressive modulus. The novel injectable PPF-based microsphere/scaffold composites developed in this study are promising to serve as vehicles for controlled drug delivery for bone tissue engineering.


Assuntos
Cimentos Ósseos/metabolismo , Substitutos Ósseos , Sistemas de Liberação de Medicamentos , Fumaratos/metabolismo , Ácido Láctico/metabolismo , Microesferas , Ácido Poliglicólico/metabolismo , Polímeros/metabolismo , Polipropilenos/metabolismo , Cimentos Ósseos/química , Regeneração Óssea , Substitutos Ósseos/química , Substitutos Ósseos/metabolismo , Preparações de Ação Retardada , Dextranos/metabolismo , Injeções , Teste de Materiais , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Propriedades de Superfície , Engenharia Tecidual/métodos , Xantenos/metabolismo
20.
Bioresour Technol ; 207: 31-8, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26868153

RESUMO

To offset the adverse effects of light attenuation on microalgae growth, hollow polymethyl methacrylate (PMMA) tubes were embedded into a flat-plate photobioreactor (PBR) as light guides. In this way, a fraction of incident light could be transmitted and emitted to the interior of the PBR, providing a secondary light source for cells in light-deficient regions. The average light intensity of interior regions 3-6cm from surfaces with 70µmolm(-2)s(-1) incident light was enhanced 2-6.5 times after 3.5days cultivation, resulting in a 23.42% increase in biomass production to that cultivated in PBR without PMMA tubes. The photosynthetic efficiency of microalgae in the proposed PBR was increased to 12.52%. Moreover, the installation of hollow PMMA tubes induced turbulent flow in the microalgae suspension, promoting microalgae suspension mixing. However, the enhanced biomass production was mainly attributed to the optimized light distribution in the PBR.


Assuntos
Chlorella vulgaris/crescimento & desenvolvimento , Chlorella vulgaris/efeitos da radiação , Luz , Microalgas/crescimento & desenvolvimento , Microalgas/efeitos da radiação , Fotobiorreatores/microbiologia , Aerobiose , Biomassa , Fotossíntese/efeitos da radiação , Polimetil Metacrilato/química
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