Effects of ultrafiltration combined with high-pressure processing,ultrasound and heat treatments on the quality of a blueberry–grape–pineapple–cantaloupe juice blend

This study investigated the effect of ultrafiltration (UF) combined with high-pressure processing (HPP) at 550 MPa, 25 °C for 5 min, ultrasound (US) at 520 W, 40 °C for 10 min and heat treatment (HT) at 90 °C for 3 min on the microbial, physicochemical and sensory properties of a blueberry–grape–pineapple–cantaloupe juice blend during 104 days of storage at 4 °C. After UF, the shelf life of the HPP- and US-treated clear juice blends were 104 and 72 days during the storage at 4 °C respectively. HPP, US and HT treatment minimally affected the anthocyanin and total phenol contents, while HPP better maintained the ascorbic acid levels and sensory properties in the clear juice blend during the storage. Therefore, HPP combined with UF was identified as a prospective processing technique in the fruit juice industry.     

Analysis of pressure and heat distribution in a dilating or contracting filter chamber with two outlets using multivariate spectral quasilinearization method

The development of efficient filters is an essential part of industrial machinery design, specifically to increase the lifespan of a machine. In the filter chamber design considered in this study, the magnetic material is placed along the horizontal surface of the filter chamber. The inside of the filter chamber is layered with a porous material to restrict the outflow of unwanted particles. This study aims to investigate the flow, pressure, and heat distribution in a dilating or contracting filter chamber with two outlets driven by injection through a permeable surface. The proposed model of the fluid dynamics within the filter chamber follows the conservation equations in the form of partial differential equations. The model equations are further reduced to a steady case through Lie's symmetry group of transformation. They are then solved using a multivariate spectral-based quasilinearization method on the Chebyshev–Gauss–Lobatto nodes. Insights and analyses of the thermophysical parameters that drive optimal outflow during the filtration process are provided through the graphs of the numerical solutions of the differential equations. We find, among other results, that expansion of the filter chamber leads to an overall decrease in internal pressure and an increase in heat distribution inside the filter chamber. The results also show that shrinking the filter chamber increases the internal momentum inside the filter, which leads to more outflow of filtrates.     

Hall current effects on MHD flow of chemically reacting fluid through a porous medium with heat source

We considered the magnetohydrodynamic (MHD) free convective flow of an incompressible electrically conducting viscous fluid past an infinite vertical permeable porous plate with a uniform transverse magnetic field, heat source and chemical reaction in a rotating frame taking Hall current effects into account. The momentum equations for the fluid flow during absorbent medium are controlled by the Brinkman model. Through the undisturbed state, both the plate and fluid are in a rigid body rotation by the uniform angular velocity perpendicular to an infinite vertical plate. The perpendicular surface is subject to the homogeneous invariable suction at a right angle to it and the heat on the surface varies about a non-zero unvarying average whereas the warmth of complimentary flow is invariable. The systematic solutions of the velocity, temperature, and concentration distributions are acquired systematically by utilizing the perturbation method. The velocity expressions consist of steady-state and fluctuating situations. It is revealed that the steady part of the velocity field has a three-layer characteristic while the oscillatory part of the fluid field exhibits a multi-layer characteristic. The influence of various governing flow parameters on the velocity, temperature, and concentration are analyzed graphically. We also discuss computational results for the skin friction, Nusselt number, and Sherwood number in the tabular forms.     

Estimates of daily oxygen consumption,carbon dioxide and methane emissions,and heat production for beef and dairy cattle using spot gas sampling

A simulation study was conducted to examine accuracy of estimating daily O₂ consumption, CO₂ and CH₄ emissions, and heat production (HP) using a spot sampling technique and to determine optimal spot sampling frequency (FQ). Data were obtained from 3 experiments where daily O₂ consumption, emissions of CO₂ and CH₄, and HP were measured using indirect calorimetry (respiration chamber or headbox system). Experiment 1 used 8 beef heifers (ad libitum feeding; gaseous exchanges measured every 30 min over 3 d in respiration chambers); Experiment 2 used 56 lactating Holstein-Friesian cows (restricted feeding; gaseous exchanges measured every 12 min over 3 d in respiration chambers); Experiment 3 used 12 lactating Jersey cows (ad libitum feeding; gaseous exchanges measured every hour for 1 d using headbox style chambers). Within experiment, averages of all measurements (FQALL) and averages of measurements selected at time points with 12, 8, 6, or 4 spot sampling FQ (i.e., sampling every 2, 3, 4, and 6 h in a 24-h cycle, respectively; FQ12, FQ8, FQ6, and FQ4, respectively) were compared. Within study a mixed model was used to compare gaseous exchanges and HP among FQALL, FQ12, FQ8, FQ6, and FQ4, and an interaction of dietary treatment by FQ was examined. A regression model was used to evaluate accuracy of spot sampling within study [i.e., FQALL (observed) vs. FQ12, FQ8, FQ6, or FQ4 (estimated)]. No interaction of diet by FQ was observed for any variables except for CH₄ production in experiment 1. No FQ effect was observed for gaseous exchanges and HP except in experiment 2 where CO₂ production was less (5,411 vs. 5,563 L/d) for FQ4 compared with FQALL, FQ12, and FQ8. A regression analysis between FQALL and each FQ within study showed that slopes and intercepts became farther from 1 and 0, respectively, for almost all variables as FQ decreased. Most variables for FQ12 and FQ8 had root mean square prediction error (RMSPE) less than 10% of the mean and concordance correlation coefficient (CCC) greater than 0.80, and RMSPE increased and CCC decreased as FQ decreased. When a regression analysis was conducted with combined data from the 3 experiments (mixed model with study as a random effect), results agreed with those from the analysis for the individual studies. Prediction errors increased and CCC decreased as FQ decreased. Generally, all the estimates from FQ12, FQ8, FQ6, and FQ4 had RMSPE less than 10% of the means and CCC greater than 0.90 except for FQ6 and FQ4 for O₂ consumption and CH₄ production. In conclusion, the spot sampling simulation with 3 indirect calorimetry experiments indicated that FQ of at least 8 samples (every 3 h in a 24-h cycle) was required to estimate daily O₂ consumption, CO₂ and CH₄ production, and HP and to detect changes in those in response to dietary treatments. This sampling FQ may be considered when using techniques that measure spot gas exchanges such as the GreenFeed and face mask systems.     

Hydrangea like composite catalysts of ultrathin Mo2S3 nanosheets assembled on N,S-dual-doped graphitic biocarbon spheres with highly electrocatalytic activity for HER

Water electrolysis is the most clean and high-efficiency technology for production of hydrogen, an ultimate clean energy in future. Highly efficient non-noble electrocatalysts for hydrogen evolution reaction (HER) are desirable for large scale production of hydrogen by water electrolysis. Especially, exposing as many active sites as possible is a vital way to improve activities of the catalysts. Herein, a series of new hydrangea like composite catalysts of ultrathin Mo₂S₃ nanosheets assembled uprightly and interlacedly on N, S-dual-doped graphitic biocarbon spheres were facilely prepared. The unique structure endowed the catalysts highly exposed edge active sites and prominently high activities for HER. Especially, the optimized catalyst Mo₂S₃/NSCS-50 exhibited as low as 106 mV of overpotential at 10 mA/cm² (denoted as ?₁₀). The catalyst also showed low Tafel slope of 53 mV/dec, low electron transfer resistance of 34 Ω and high stability evidenced by the result that the current density only attenuated 11.7% after 10 h i-t test. The catalyst has shown broad prospect for commercial application in water electrolysis.     

Simulation of interaction between high-temperature process and heat emission from electricity system in summer

During the hot summer season, using electricity systems increases the local anthropogenic heat emission, further increasing the temperature. Regarding anthropogenic heat sources, electric energy consumption, heat generation, indoor and outdoor heat transfer, and exchange in buildings play a critical role in the change in the urban thermal environment. Therefore, the Weather Research and Forecasting (WRF) Model was applied in this study to investigate the heat generation from an indoor electricity system and its influence on the outdoor thermal environment. Through the building effect parameterization (BEP) of a multistorey urban canopy scheme, a building energy model (BEM) to increase the influence of indoor air conditioning on the electricity consumption system was proposed. In other words, the BEP+BEM urban canopy parameterization scheme was set. High temperatures and a summer heat wave were simulated as the background weather. The results show that using the BEP+BEM parameterization scheme of indoor and outdoor energy exchange in the WRF model can better simulate the air temperature near the surface layer on a sunny summer. During the day, the turning on the air conditioning and other electrical systems have no obvious effect on the air temperature near the surface layer in the city, whereas at night, the air temperature generally increases by 0.6 ℃, especially in densely populated areas, with a maximum temperature rise of approximately 1.2 ℃ from 22:00 to 23:00. When the indoor air conditioning target temperature is adjusted to 25–27 ℃, the total energy release of the air conditioning system is reduced by 12.66%, and the temperature drops the most from 13:00 to 16:00, with an average of approximately 1 ℃. Further, the denser the building is, the greater the temperature drop.     

Effect of metal oxide nanofluids on the performance of passive solar still single slope for two different absorbent plates

This study aims to improve the performances of a solar still single slope using metal oxide nanofluid (Al₂O₃–water, Cu₂O–water, and TiO₂–water). The numerical study was carried out for the climatic conditions of Agadir, Morocco, with different concentrations of nanofluids inside a basin equipped with an absorber plate with two different absorptivities. The numerical study is based on thermal balance equations applied on different solar system components and solved using the Runge Kutta method. The numerical model is validated by comparing our results with the literature available data. A comparison study of the effect of these nanofluids on solar still productivity is done. The results show that the productivity of the solar still using nanoparticles Cu₂O, TiO₂, and Al₂O₃ are 7.38, 7.1, and 7.064 kg m⁻² day⁻¹, respectively. It is obtained that the maximum efficiency of the solar still is found to be 55.27% by using cuprous oxide nanoparticles. Furthermore, an enhancement in solar still productivity of 6.36%, 19.54%, and 33.25% is obtained by dispersing 1%, 3%, and 5% volume fraction of Cu₂O nanoparticles in pure water, respectively compared to the conventional solar. Moreover, the impact of the absorptivity of the absorber plate on the solar still effectiveness is investigated. Two types of coatings are considered to change the absorber plate absorptivity. The results indicate that the efficiencies of the solar system are 58.81% and 51.77% using an absorber plate with 0.95 and 0.85 of absorptivity, respectively.     

雪菊精油对希氏肠球菌产酪胺及相关基因表达的影响

探讨不同质量浓度雪菊精油对希氏肠球菌（Enterococcus hirae）N47产酪胺的影响机制。利用反转录实时定量聚合酶链式反应分析E. hirae在雪菊精油作用下酪氨酸脱羧途径相关基因的表达情况；利用高效液相色谱法检测不同质量浓度雪菊精油对E. hirae产酪胺的影响。并将E. hirae接入到含不同质量浓度雪菊精油的熏马肠中发酵，评估香肠pH值、菌落总数和酪胺积累量。结果表明：在E. hirae纯培养体系和熏马肠体系中，雪菊精油通过抑制微生物的生长和酪氨酸脱羧途径中tyr DC、tyr P基因的表达，降低酪胺的积累量（P＜0.05）。当雪菊精油添加量为1/2最小抑菌浓度（minimal inhibitory concentration，MIC）和MIC时，熏马肠中酪胺的含量分别为78.52 mg/kg和45.83 mg/kg，较对照组分别减少了64.72%和79.41%。     

基于乙酰胆碱酯酶和氧化应激研究海胆酮对阿尔茨海默症的作用机制

海胆酮是一种酮式类胡萝卜素，主要从海胆及藻类等海洋生物中提取。本文研究海胆酮对乙酰胆碱酯酶（acetylcholinesterase，AChE）的抑制作用，应用酶动力学、荧光光谱、圆二色光谱和分子对接技术研究海胆酮对AChE的抑制机理，并用淀粉样β蛋白片段25～35（amyloid beta-peptide 25-35，Aβ25-35）诱导大鼠肾上腺嗜铬细胞瘤细胞（PC12细胞）建立阿尔茨海默症（Alzheimer’s disease，AD）模型，研究海胆酮对AD细胞模型氧化应激损伤的作用。结果表明，海胆酮有很强的AChE抑制活性，其半抑制质量浓度为（16.29±0.97）μg/mL，抑制常数Ki为3.82 μg/mL，表现为竞争性抑制；海胆酮可诱导AChE二级结构改变，更容易与AChE活性中心氨基酸Ser200、His440、Trp84和Tyr121结合，阻碍底物碘代硫代乙酰胆碱（acetylthiocholine iodide，ATCI）与酶结合，从而引起酶活力降低。海胆酮能有效抑制Aβ25-35诱导PC12细胞的AChE活力，降低丙二醛含量，增加超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶活力，减轻Aβ25-35诱导的PC12细胞氧化应激损伤。本研究基于AChE和氧化应激阐明了海胆酮对AD的潜在作用机制，为海胆酮在功能食品、生物医药等领域的应用提供了数据支持和理论根据。