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1.
Nat Protoc ; 15(3): 822-839, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32051614

RESUMO

This protocol describes the use of 9-fluorenone as a cheap and non-toxic photocatalyst for the oxidation of non-activated alcohols performed under the irradiation of a blue light-emitting diode. It also describes the use of the similarly cheap and non-toxic photocatalyst rose bengal for the selective α-oxygenation of tertiary amines to produce the corresponding amides in a selective way using the same light source. We have provided detailed instructions on how to assemble the light-emitting diode equipment and set up the photocatalytic reaction, where an oxygen atmosphere is created with an O2-filled balloon. Further details are provided using four example reactions that illustrate how this system works: alcohol oxidation to prepare terephthlalaldehyde and androstanedione, and amine oxidation to make 2-phenyl-3,4-dihydroisoquinolin-1(2H)-one and (4-((4-chlorophenyl)(phenyl)methyl)piperazin-1-yl)m-tolyl)methanone. The times needed to perform these photocatalytic reactions are 18, 76, 22 and 54 h, respectively. We believe that this protocol represents a robust methodology for the late-stage modification of amines and the selective oxidation of steroids.


Assuntos
Álcoois/química , Aminas/química , Metais/química , Oxigênio/química , Ar , Catálise , Processos Fotoquímicos
2.
Nat Commun ; 11(1): 766, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-32034144

RESUMO

Human influenza A viruses are known to be transmitted via the air from person to person. It is unknown from which anatomical site of the respiratory tract influenza A virus transmission occurs. Here, pairs of genetically tagged and untagged influenza A/H1N1, A/H3N2 and A/H5N1 viruses that are transmissible via the air are used to co-infect donor ferrets via the intranasal and intratracheal routes to cause an upper and lower respiratory tract infection, respectively. In all transmission cases, we observe that the viruses in the recipient ferrets are of the same genotype as the viruses inoculated intranasally, demonstrating that they are expelled from the upper respiratory tract of ferrets rather than from trachea or the lower airways. Moreover, influenza A viruses that are transmissible via the air preferentially infect ferret and human nasal respiratory epithelium. These results indicate that virus replication in the upper respiratory tract, the nasal respiratory epithelium in particular, of donors is a driver for transmission of influenza A viruses via the air.


Assuntos
Furões/virologia , Vírus da Influenza A/fisiologia , Mucosa Nasal/virologia , Infecções por Orthomyxoviridae/transmissão , Ar , Animais , Cães , Feminino , Humanos , Vírus da Influenza A/genética , Vírus da Influenza A/patogenicidade , Células Madin Darby de Rim Canino , Infecções por Orthomyxoviridae/veterinária , Tropismo Viral
3.
Water Res ; 173: 115570, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32062221

RESUMO

Recent findings have demonstrated that activated sludge morphology significantly impacts oxygen transfer efficiency (OTE) in the activated sludge process. In this study, we developed a mechanistic understanding of this impact. Mixed liquor samples collected from a domestic wastewater treatment plant (WWTP) were blended with a bulking activated sludge from a bench scale reactor (BSR) cultured on synthetic wastewater to manipulate various morphological parameters such as the settled sludge volume (SV), the sludge volume index (SVI), and the specific filament length (SFL). The filaments that were present in the blended sludges consisted largely of Type 0041 and Type 021N, which are commonly found in WWTPs that treat domestic wastewater. Variations in sludge morphology, as quantified by settled sludge volume after 30 min (SV30), SVI, and SFL, systematically affected the mixed liquor apparent viscosity (µapp), which consequently impacted OTE. An increase in the SFL from 9.61 × 106 µm g-1 to 6.88 × 107 µm g-1 resulted in a 41.4% increase in apparent viscosity and a 24.6% decrease in volumetric mass transfer coefficient (KLa). A new parameter, named the ultimate settleability (SVULT), was developed by curve fitting the SV versus time data and found to relate with µapp through an expanded form of the Einstein Equation for the viscosity. Therefore, SVULT is a corollary for the particle volume fraction that incorporates effects of both the sludge morphology and mass concentration on µapp. Theoretical derivation revealed that an increase in SVULT resulted in an increase in µapp, which reduced oxygen transfer by increasing the air bubble size and reducing refreshment of the liquid at the gas-liquid interface. The KLa was found to be inversely proportional to µapp0.75 through fitting the experimental data with the theoretical model. Using a variance-based global sensitivity analysis, three operating parameters that have the most impact on oxygen transfer were identified: the power input per unit volume, the superficial gas flowrate, and the µapp.


Assuntos
Oxigênio , Esgotos , Ar , Reatores Biológicos , Viscosidade , Eliminação de Resíduos Líquidos , Águas Residuárias
4.
Br J Radiol ; 93(1107): 20190919, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32003576

RESUMO

OBJECTIVE: Monte Carlo (MC) simulations substantially improve the accuracy of predicted doses. This study aims to determine and quantify the uncertainties of setting up such a MC system. METHODS: Doses simulated with two Geant4-based MC calculation codes, but independently tuned to the same beam data, have been compared. Different methods of MC modelling of a pre-absorber have been employed, either modifying the beam source parameters (descriptive) or adding the pre-absorber as a physical component (physical). RESULTS: After the independent beam modelling of both systems in water (resulting in excellent range agreement) range differences of up to 3.6/4.8 mm (1.5% of total range) in bone/brain-like tissues were found, which resulted from the use of different mean water ionisation potentials during the energy tuning process. When repeating using a common definition of water, ranges in bone/brain agreed within 0.1 mm and gamma-analysis (global 1%,1mm) showed excellent agreement (>93%) for all patient fields. However, due to a lack of modelling of proton fluence loss in the descriptive pre-absorber, differences of 7% in absolute dose between the pre-absorber definitions were found. CONCLUSION: This study quantifies the influence of using different water ionisation potentials during the MC beam modelling process. Furthermore, when using a descriptive pre-absorber model, additional Faraday cup or ionisation chamber measurements with pre-absorber are necessary. ADVANCES IN KNOWLEDGE: This is the first study quantifying the uncertainties caused by the MC beam modelling process for proton pencil beam scanning, and a more detailed beam modelling process for MC simulations is proposed to minimise the influence of critical parameters.


Assuntos
Método de Monte Carlo , Terapia com Prótons/métodos , Incerteza , Absorção de Radiação , Ar , Osso e Ossos/efeitos da radiação , Encéfalo/efeitos da radiação , Humanos , Hipofracionamento da Dose de Radiação , Dosagem Radioterapêutica , Reprodutibilidade dos Testes , Água
5.
PLoS One ; 15(1): e0228043, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978205

RESUMO

This study aims to analyze the thermal biology and climatic vulnerability of two closely related lizard species (Stenocercus festae and S. guentheri) inhabiting the Ecuadorian Andes at high altitudes. Four physiological parameters-body temperature (Tb), preferred temperature (Tpref), critical thermal maximum (CTmax), and critical thermal minimum (CTmin)-were evaluated to analyze the variation of thermophysiological traits among these populations that inhabit different environmental and altitudinal conditions. We also evaluate the availability of operative temperatures, warming tolerance, and thermal safety margin of each population to estimate their possible risks in the face of future raising temperatures. Similar to previous studies, our results suggest that some physiological traits (CTmax and Tb) are influenced by environmental heterogeneity, which brings changes on the thermoregulatory behavior. Other parameters (Tpref and CTmin), may be also influenced by phylogenetic constraints. Moreover, the fluctuating air temperature (Tair) as well as the operative temperatures (Te) showed that these lizards exploit a variety of thermal microenvironments, which may facilitate behavioral thermoregulation. Warming tolerance and thermal safety margin analyses suggest that both species find thermal refugia and remain active without reducing their performance or undergoing thermal stress within their habitats. We suggest that studies on the thermal biology of tropical Andean lizards living at high altitudes are extremely important as these environments exhibit a unique diversity of microclimates, which consequently result on particular thermophysiological adaptations.


Assuntos
Mudança Climática , Lagartos/fisiologia , Temperatura , Clima Tropical , Adaptação Fisiológica , Ar , Animais , Equador
6.
PLoS One ; 15(1): e0227980, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978133

RESUMO

INTRODUCTION: Particles in exhaled air (PEx) provide samples of respiratory tract lining fluid from small airways containing, for example, Surfactant protein A (SP-A) and albumin, potential biomarkers of small airway disease. We hypothesized that there are differences between morning, noon, and afternoon measurements and that the variability of repeated measurements is larger between days than within days. METHODS: PEx was obtained in sixteen healthy non-smoking adults on 11 occasions, within one day and between days. SP-A and albumin were quantified by ELISA. The coefficient of repeatability (CR), intraclass correlation coefficient (ICC), and coefficient of variation (CV) were used to assess the variation of repeated measurements. RESULTS: SP-A and albumin increased significantly from morning towards the noon and afternoon by 13% and 25% on average, respectively, whereas PEx number concentration and particle mean mass did not differ significantly between the morning, noon and afternoon. Between-day CRs were not larger than within-day CRs. CONCLUSIONS: Time of the day influences the contents of SP-A and albumin in exhaled particles. The variation of repeated measurements was rather high but was not influenced by the time intervals between measurements.


Assuntos
Albuminas/isolamento & purificação , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Proteína A Associada a Surfactante Pulmonar/isolamento & purificação , Sistema Respiratório/química , Adulto , Idoso , Ar/análise , Albuminas/metabolismo , Biomarcadores/química , Testes Respiratórios , Expiração/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Doença Pulmonar Obstrutiva Crônica/metabolismo , Doença Pulmonar Obstrutiva Crônica/patologia , Proteína A Associada a Surfactante Pulmonar/metabolismo , Sistema Respiratório/metabolismo , Espirometria/métodos
7.
Biophys Chem ; 258: 106317, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31918025

RESUMO

The antimicrobial activity of amphotericin B (AmB) depends on its interaction with ergosterol-containing cell membranes of fungus. Cholesterol is a sterol in mammalian cell membrane, and its structure is very similar to ergosterol, which caused to the toxic of amphotericin B to mammalian or human cell membranes. Even so, it is still the gold standard for the treatment of fungal infections. The mechanism of its toxicity to mammalian cell membrane has become a hot topic. The toxicity mechanism of amphotericin B on the cell membrane is also related to the phospholipids on the membrane. The effects of saturated and unsaturated fat chains on the interaction of amphotericin B with phospholipid monolayers containing cholesterol or ergosterol were studied at the molecular level using an air-water interface monolayer model. Both atomic force microscope and Brewster angle microscope were used to observe the surface morphology of the monolayer. The analysis of limiting molecular area suggested that the interaction between AmB and the two kinds of sterol is significantly different on the unsaturated lipid monolayer. According to the elastic modulus, the AmB molecules can increase the compressibility or viscoelasticity of the phospholipid/sterol monolayer. However, this impact of AmB on the DOPC/sterol monolayer containing ergosterol was stronger than that containing cholesterol at 25 ~ 50 mN/m. While this impact of AmB on the DPPC/sterol monolayer containing cholesterol was stronger than that containing ergosterol at 32 ~ 56 mN/m. The excess Gibbs free energy of the monolayer showed that, in the presence of saturated fat chain, amphotericin B could make the molecules of the DPPC/cholesterol monolayer and the DPPC/ergosterol monolayer arrange more closely and make intermolecular interaction stronger. There was no significant difference between DPPC/cholesterol monolayer and DPPC/ergosterol monolayer. However, in the presence of unsaturated chain, the effects of amphotericin B on the DOPC/cholesterol monolayer and the DOPC/ergosterol monolayer were significantly different. Amphotericin B made the molecular arrangement of DOPC/ergosterol monolayer more loosed, and the intermolecular force weakened at 5-35 mN/m. AFM images reflect that AmB can perforate the phospholipid-ergosterol monolayer, which was no significant correlation with saturation of the lipid monolayer. But the areas of dark areas shaped holes on the DPPC/ergosterol monolayer were larger than that on the DOPC/ergosterol monolayer. The adsorption of amphotericin B on lipid/sterol monolayer suggests that the orientation of amphotericin B may be different when it is inserted into the monolayer of phospholipid-sterol in the presence of saturated or unsaturated chains. The results are helpful to understand the complex mechanism of toxicity of amphotericin B to cell membrane.


Assuntos
Anfotericina B/química , Antibacterianos/química , Colesterol/química , Ergosterol/química , Fosfolipídeos/química , Ar , Humanos , Tamanho da Partícula , Pressão , Propriedades de Superfície , Água/química
8.
Biophys Chem ; 258: 106329, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31954222

RESUMO

Viscoelastic properties of molecular assemblies formed by mixing poly (l-lysine) (PLL) and poly (l-glutamic acid) (PGA) at pH = 7.5 have been studied using Quartz crystal microbalance with dissipation (QCM-D). The inter-molecular complex between PLL and PGA arising from strong electrostatic interaction, leads to local changes in secondary structure resulting in intra-molecular complexes. ATR-FTIR analysis of the Secondary structural features of PLL, suggest an abundance of anti-parallel beta sheet that causes a significant change in the morphology of the self-assembled structures. A combination of spectroscopy, Brewster angle microscopy (BAM), Transmission electron and scanning electron microscopy show that an inverse relationship exists between the elasticity of the different PLL + PGA mixed films and the % anti parallel beta sheet conformation. The elastic moduli for the mixtures change from about 0.913 ± 0.01 GPa for pure PLL to about 0.764 ± 0.01 GPa in the mixture when PGA increases. The localized breaking and reformation of the ion pairs in the complex control their sizes and show an inverse relationship with the elastic moduli. The rheological profiles of the films, elastic moduli, together with their surface morphology from microscopy (TEM) and (SEM) confirmed their increasing propensity to self-assemble in one dimension to form tapes, colloidal particles and their composite assemblies.


Assuntos
Elasticidade , Peptídeos/química , Ar , Modelos Moleculares , Tamanho da Partícula , Conformação Proteica , Técnicas de Microbalança de Cristal de Quartzo , Espectroscopia de Infravermelho com Transformada de Fourier
9.
Ann Otol Rhinol Laryngol ; 129(2): 157-163, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31569953

RESUMO

OBJECTIVE: Velopharyngeal (VP) closure has high impact on the quality of life, especially in patients with cleft palate. For better understanding the VP closure, it is important to understand the airflow dynamics of different closure patterns, including circular, coronal, sagittal, and circular with a Passavant's ridge. The purpose of this study was to demonstrate the airflow characteristics of different velopharyngeal closure patterns. METHODS: Sixteen adults with no notable upper airway abnormality who needed multislice spiral computed tomography scans as part of their clinical care. Airways were reconstructed. A cylinder and a cuboid were used to replace the VP port in three models of VP port patterns. Flow simulations were carried using computational fluid dynamics. Airflow pressures in the VP orifice, oral cavity and nasal cavity, as well as airflow velocity through the velopharyngeal orifice, were calculated. RESULTS: The airflow dynamics at the velopharynx were different among different velopharyngeal patterns as the area of the velopharyngeal port increased from 0 to 25 mm2. The orifice areas of different closure conditions in four velopharyngeal closure patterns were significantly different. The maximal orifice area for adequate velopharyngeal closure was 7.57 mm2 in the coronal pattern and 6.21 mm2 in the sagittal pattern. CONCLUSIONS: Airflow dynamics of the velopharynx were correlated to the velopharyngeal closure patterns. Different closure patterns had different largest permitted orifice areas for getting the appropriate oral pressures for normal speech.


Assuntos
Faringe/fisiopatologia , Insuficiência Velofaríngea/fisiopatologia , Adulto , Ar , Feminino , Humanos , Hidrodinâmica , Masculino , Software , Adulto Jovem
10.
Environ Pollut ; 256: 112050, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31481270

RESUMO

A dissolved air flotation (DAF) system is one of the water treatment processes that purifies contaminants through a buoyancy effect by attaching the moiety of micro-bubbles on their free surface. Since the DAF system was first used in the drinking water treatment in the 1960s, it has been recognized as an effective treatment for the water purification process. Most previous works laid great emphasis on the internal flow behaviors of fluid to improve the purification efficiency of the DAF system. Nevertheless, the practical implementation with a pilot plant indeed revealed some technical incompleteness for the DAF system. To circumvent for the technical incompleteness, numerical simulation based on computational fluid dynamics (CFD) has been carried out to understand the in-depth knowledge on internal flow phenomena in the DAF system. However, the standard k-ε turbulence model has been conventionally used in the most studies without any proper consideration process. Accordingly, the objectives of this study were to investigate the major effects on the internal flow behaviors for an efficient numerical simulation of DAF when a different turbulence model and micro-bubble parameters are used. As a result, the present study found that the standard k-ε model would be not proper for the internal flow simulation of the DAF process and a careful consideration would be required for a more accurate prediction. In addition, the present study examined a desirable internal flow pattern with various operating conditions of the micro-bubble. Consequently, the main findings of this study are expected to provide realistic information to related researchers for designing the DAF system with the optimal operating parameters.


Assuntos
Ar/análise , Hidrodinâmica , Microbolhas , Modelos Teóricos , Águas Residuárias/química , Purificação da Água/métodos , Simulação por Computador
11.
Br J Radiol ; 93(1107): 20190598, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31782941

RESUMO

OBJECTIVES: To describe the measurements and to present the results of the beam commissioning and the beam model validation of a compact, gantry-mounted, spot scanning proton accelerator system with dynamic layer-by-layer field collimation. METHODS: We performed measurements of depth dose distributions in water, spot and scanned field size in air at different positions from the isocenter plane, spot position over the 20 × 20 cm2 scanned area, beam monitor calibration in terms of absorbed dose to water and specific field collimation measurements at different gantry angles to commission the system. To validate the beam model in the treatment planning system (TPS), we measured spot profiles in water at different depths, absolute dose in water of single energy layers of different field sizes and inversely optimised spread-out Bragg peaks (SOBP) under normal and oblique beam incidence, field size and penumbra in water of SOBPs, and patient treatment specific quality assurance in homogeneous and heterogeneous phantoms. RESULTS: Energy range, spot size, spot position and dose output were consistent at all gantry angles with 0.3 mm, 0.4 mm, 0.6 mm and 0.5% maximum deviations, respectively. Uncollimated spot size (one sigma) in air with an air-gap of 10 cm ranged from 4.1 to 16.4 mm covering a range from 32.2 to 1.9 cm in water, respectively. Absolute dose measurements were within 3% when comparing TPS and experimental data. Gamma pass rates >98% and >96% at 3%/3 mm were obtained when performing 2D dose measurements in homogeneous and in heterogeneous media, respectively. Leaf position was within ±1 mm at all gantry angles and nozzle positions. CONCLUSIONS: Beam characterisation and machine commissioning results, and the exhaustive end-to-end tests performed to assess the proper functionality of the system, confirm that it is safe and accurate to treat patients. ADVANCES IN KNOWLEDGE: This is the first paper addressing the beam commissioning and the beam validation of a compact, gantry-mounted, pencil beam scanning proton accelerator system with dynamic layer-by-layer multileaf collimation.


Assuntos
Ciclotrons , Terapia com Prótons/instrumentação , Absorção de Radiação , Ar , Calibragem , Certificação , Desenho de Equipamento , Humanos , Países Baixos , Imagens de Fantasmas , Terapia com Prótons/métodos , Radiometria/métodos , Reprodutibilidade dos Testes , Água
12.
Plant Dis ; 104(1): 82-93, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31738689

RESUMO

The lettuce downy mildew pathogen, Bremia lactucae, is an obligate oomycete that causes extensive produce losses. Initial chlorotic symptoms that severely reduce the market value of the produce are followed by the appearance of white, downy sporulation on the abaxial side of the leaves. These spores become airborne and disseminate the pathogen. Controlling lettuce downy mildew has relied on repeated fungicide applications to prevent outbreaks. However, in addition to direct economic costs, heterogeneity and rapid adaptation of this pathogen to repeatedly applied fungicides has led to the development of fungicide-insensitivity in the pathogen. We deployed a quantitative PCR assay-based detection method using a species-specific DNA target for B. lactucae coupled with a spore trap system to measure airborne B. lactucae spore loads within three commercial fields that each contained experimental plots, designated EXP1 to EXP3. Based upon these measurements, when the spore load in the air reached a critical level (8.548 sporangia per m3 air), we advised whether or not to apply fungicides on a weekly basis within EXP1 to EXP3. This approach saved three sprays in EXP1, and one spray each in EXP2 and EXP3 without a significant increase in disease incidence. The reduction in fungicide applications to manage downy mildew can decrease lettuce production costs while slowing the development of fungicide resistance in B. lactucae by eliminating unnecessary fungicide applications.


Assuntos
Agricultura , Microbiologia do Ar , Alface , Oomicetos , Reação em Cadeia da Polimerase , Esporos Fúngicos , Agricultura/métodos , Ar , Alface/microbiologia , Oomicetos/genética , Doenças das Plantas/microbiologia , Esporos Fúngicos/genética
13.
Food Chem ; 306: 125644, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31610329

RESUMO

Far infrared radiation (FIR) and hot air drying (HA) were applied to unpolished and polished pigmented rice varieties. Ferulic acid is a major phenolic acid in pigmented rice, being three-fold greater in bound form than in soluble form. Overall, FIR increased total phenolic and flavonoid contents, anthocyanin, tocopherols as well as antioxidant capacity, whereas the opposite results were observed for HA in all samples. Gallic, and ferulic acids were significantly (p < 0.05) increased in FIR dried samples. Quercetin content was significantly increased in unpolished rice dried by FIR and HA. Cyanidin-3-glucoside was greatly increased by FIR. Amino acids were decreased less by HA than did FIR. Our findings suggest that HA and FIR may have a significant effect on the internal structure of the grain, which may increase the yield of extraction of some components, including the bioactives.


Assuntos
Aminoácidos/química , Oryza/química , Ar , Aminoácidos/metabolismo , Antocianinas/análise , Antioxidantes/análise , Ácidos Cumáricos/análise , Grão Comestível/química , Hidroxibenzoatos/análise , Raios Infravermelhos
14.
Food Chem ; 305: 125477, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31610424

RESUMO

In recent years there is an increasing interest in dried fruits, although many of their nutritional components are readily lost during drying. The novelty of this paper was to assess the effect of hot-air drying (HAD) and far-infrared drying (FIRD) on the physicochemical properties and microstructure of mango slices pretreated with: control; 0.1% citric acid + 0.5% ascorbic acid + 0.5% CaCl2 + 1% NaCl; or 0.1% citric acid + 0.5% ascorbic acid + 0.5% CaCl2 + 1% NaCl + ultrasound treatments. Pretreatments resulted in a significant (p < 0.05) increase in reducing sugar, ascorbic acid and total phenol contents of dried samples. Moreover, compared with HAD, FIRD maintained a higher phenolic acid content, improved the nutrient retention and color attributes and better preserved microstructure. Therefore, pretreatments followed by FIRD is a potential method for obtaining high-quality dried mango slices.


Assuntos
Ácido Ascórbico/análise , Dessecação/métodos , Mangifera/química , Fenóis/análise , Ar , Cloreto de Cálcio/química , Cromatografia Líquida de Alta Pressão , Cor , Frutas/química , Frutas/metabolismo , Temperatura Alta , Raios Infravermelhos , Mangifera/metabolismo , Mangifera/ultraestrutura , Espectrometria de Massas , Sonicação
15.
Food Microbiol ; 85: 103281, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500700

RESUMO

This study investigated the effectiveness of three thermal treatments; hot air (HA), hot water immersion (HWI), and hot water spraying (HWS); alone and in combination with radio frequency (RF) on the inactivation of Salmonella Typhimurium in shell eggs. In addition, the physical quality of the treated eggs and their functional capability to produce angel food cakes were determined. The results showed that HWI and HWS were significantly (P < 0.05) more effective at pasteurizing shell eggs than HA, and the pasteurization time was significantly reduced when eggs were first processed with RF. The times needed for RF/HWI and RF/HWS to achieve 5-log reductions of S. Typhimurium were 19.5 and 24.5 min, respectively. Yolk index was unaffected by heating, but Haugh unit and albumen turbidity were increased dependent on the length of treatment. Eggs after HWI, combined RF/HWI, and RF/HWS treatments were able to make good angel food cakes if whipping times were extended. The results of this study demonstrated that combined RF/HWS treatment was comparable to RF/HWI treatment in terms of shell egg pasteurization without damaging egg quality. Therefore, both HWS and HWI may be used as the second step of radio frequency pasteurization.


Assuntos
Casca de Ovo/microbiologia , Temperatura Alta , Viabilidade Microbiana , Pasteurização/métodos , Ondas de Rádio , Ar , Animais , Salmonella typhimurium , Água
16.
Water Sci Technol ; 80(6): 1196-1204, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31799963

RESUMO

Anaerobic digestion effluent (ADE) from the anaerobic digestion treatment of citric acid wastewater can be reused as a potential substitute for process water in the citric acid fermentation. However, excessive sodium contained in ADE significantly decreases citric acid production. In this paper, the inhibition mechanism of sodium on citric acid fermentation was investigated. We demonstrated that excessive sodium did not increase oxidative stress for Aspergillus niger, but reduced the pH of the medium significantly over the period 4-24 h, which led to lower activities of glucoamylase and isomaltase secreted by A. niger, with a decrease of available sugar concentration and citric acid production. ADE was pretreated by air-stripping prior to recycle and 18 g/L calcium carbonate was added at the start of fermentation to control the pH of the medium. The inhibition caused by ADE was completely alleviated and citric acid production substantially increased from 118.6 g/L to 141.4 g/L, comparable to the fermentation with deionized water (141.2 g/L). This novel process could decrease wastewater discharges and fresh water consumption in the citric acid industry, with benefit to the environment.


Assuntos
Ácido Cítrico , Águas Residuárias , Ar , Anaerobiose , Fermentação , Concentração de Íons de Hidrogênio
17.
Washington, D.C.; OPS; 2019-12-11. (OPS/NMH/19-014).
em Espanhol | PAHO-IRIS | ID: phr-51752

RESUMO

[Introducción]. Las enfermedades no transmisibles (ENT), en particular las enfermedades cardiovasculares, el cáncer, la diabetes y las enfermedades respiratorias crónicas, son las principales causas de muerte y ocasionan aproximadamente el 80% de las defunciones en la Región de las Américas. Las ENT pueden prevenirse reduciendo sus principales factores de riesgo: el consumo de tabaco, el consumo nocivo de alcohol, una alimentación poco saludable y la inactividad física. El número de muertes prematuras causadas por las ENT puede mitigarse mediante la detección, la atención y el tratamiento oportunos de las enfermedades. La agenda de las ENT se ha ampliado más allá de este concepto de cuatro enfermedades y cuatro factores de riesgo. La salud mental se incluye también en la agenda global de las ENT, y la contaminación del aire, reconocida a nivel mundial como un factor de riesgo significativo para las enfermedades cardiovasculares y las enfermedades respiratorias crónicas, ahora está incluida como el quinto factor de riesgo de las ENT. En este documento se analiza la agenda 5x5 de las ENT y se presenta un panorama general de los datos sobre las ENT y los factores de riesgo en la Región de las Américas, para cada categoría de las enfermedades y cada factor de riesgo por sexo, y para los 35 Estados Miembros de la Organización Panamericana de la Salud. Su objetivo es brindar un panorama visual del estado actual de la mortalidad y la prevalencia de los factores de riesgo de las ENT, y señalar la importancia de la carga de las ENT en toda la Región.


Assuntos
Doença Crônica , Fatores de Risco , Pressão Sanguínea , Ar , Doenças Respiratórias , Doenças Cardiovasculares , Neoplasias , Saúde Mental , Estilo de Vida , Abandono do Uso de Tabaco , Obesidade , Mortalidade , América
18.
Chem Commun (Camb) ; 55(100): 15117-15120, 2019 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-31782438

RESUMO

A nitrogen doped bio-carbon catalyst with high specific surface area and a hierarchical interconnected porous structure was fabricated by an in situ gas-foaming strategy from sodium alginate and ammonium chloride. The optimized catalyst displays a fabulous ORR activity, providing a facile approach for the mass production of metal-free bio-carbon catalysts in fuel cells and metal-air batteries.


Assuntos
Carbono/química , Fontes de Energia Elétrica , Gases/química , Nitrogênio/química , Ar , Alginatos/química , Cloreto de Amônio/química , Catálise , Porosidade , Zinco/química
19.
Chem Pharm Bull (Tokyo) ; 67(10): 1042-1045, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31582624

RESUMO

Biaryls are important compounds with widespread applications in many fields. Tetramethylammonium fluoride tetrahydrate was found to promote the biaryl coupling of aryl iodides bearing electron-withdrawing substituents with unactivated arenes. The reaction takes place at temperatures between 100 and 150°C and can be applied to a wide range of aromatic and heteroaromatic rings, affording the products in moderate to high yields. The reaction does not require strong bases or expensive additives that are employed in the existing methods and can be conducted in air and moisture without any precautions.


Assuntos
Hidrocarbonetos Aromáticos/química , Hidrocarbonetos Iodados/química , Compostos de Amônio Quaternário/química , Ar , Estrutura Molecular , Temperatura , Água/química
20.
Environ Sci Technol ; 53(21): 12882-12892, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31566362

RESUMO

Soft sediments exhibit complex and varied deformation behavior during in situ bubble growth; however, the sediment microstructure is often neglected when predicting bubble networking or fracture propagation dynamics. This study considers three chemically similar Mg(OH)2-rich sediments, which differ slightly in their particle size distributions and morphologies but exhibit significant differences in their porosity, stiffness, and pore throat dimensions at equivalent yield strengths. At low yield strengths, microstructure greatly influenced the size distribution and connectivity of spherical bubble populations, with narrow sedimentary pore throats promoting coarser bubbles with diminished connectivity. Increased connectivity of the bubble population appeared highly significant in limiting bed expansion, either by establishing pathways for gas release or by dissipating excess internal bubble pressure, thereby diminishing further growth. During in situ gas generation, each sediment demonstrated a critical fracture strength, which demarcated the populations with high void fractions (0.27 < ν < 0.4) of near-spherical bubbles from a fracturing regime supporting reduced void fractions (ν ≈ 0.15) of high aspect ratio cracks. However, critical fracture strengths varied significantly (in the 60-1000 Pa range) between sediments, with coarser-grained and higher porosity sediments promoting fracture at lower strengths. Fracture propagation greatly enhanced the connectivity and diminished the tortuosity of the void networks, thereby augmenting the continuous gas release flux.


Assuntos
Sedimentos Geológicos , Ar , Sedimentos Geológicos/química , Porosidade
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