Influence of CuO addition to BaSm2Ti4O12 microwave ceramics on sintering behavior and dielectric properties

Microwave dielectric ceramics of tungsten–bronze-type BaSm₂Ti₄O₁₂ were prepared by doping CuO (up to 2 wt.%) as the liquid-phase sintering aid. The effects of CuO additive on the densification, micro structure and dielectric properties were investigated. Due to the liquid-phase effect, the sintering temperature of BaSm₂Ti₄O₁₂ ceramics with 1 wt.% CuO addition can be effectively reduced to 1160 °C, about 200 °C lower than that of pure BaSm₂Ti₄O₁₂ ceramics, while good microwave dielectric properties of ɛ_r = 75.8, Q*f = 4914.6 GHz and τ_f = −7.65 ppm/°C were still achieved.     

Yield,water use efficiency and economic analysis of energy sorghum in South Texas

Yields, water use efficiency and economic returns (net farm revenues) of biomass sorghum [Sorghum bicolor (L.) Moench] were investigated over two years (2012 and 2014) under limited water resource conditions. Energy sorghum was grown under four water supply regimes: rain-fed (or dry-land, level 1), 50% (level 2), 75% (level 3) and 100% (level 4) of crop evapotranspiration rates (% ET_c). Biomass yields ranged from 5.8 to 16.6 Mg ha⁻¹ (dry weight) after 126 days of growth. Average water use efficiencies ranged from 3.95 kg m⁻³ to 23.4 kg m⁻³. Net return was approximately 410 $ ha⁻¹ with water depths above 400 ha-mm. These results suggest that it is possible to obtain more than 60 Mg ha⁻¹ of sorghum biomass (wet basis) with at least 425 mm of water. While biomass yield under irrigation was greater than rain-fed conditions, there were no significant differences among irrigation treatments. Biomass chemical composition did not differ significantly among water treatments suggesting that biofuel quality would not be affected by water deficits.     

植物源杀螨剂研究与应用前景

对近年来国内外植物性杀螨剂在杀螨植物、杀螨作用方式和作用机理方面的研究进行了综述。目前杀螨植物主要有楝科、菊科、瑞香科、茄科、豆科、藜科、唇形花科、伞形花科等共计约100余种。并展望了植物源杀螨剂在未来农业发展中的应用前景。     

Review of the structural characterization,quality evaluation,and industrial application of Lycium barbarum polysaccharides

BackgroundLycium barbarum polysaccharides (LBPs) are considered to be the major bioactive components in L. barbarum. Due to the considerable health benefits of LBPs, and the significant research interest in LBPs, quality evaluation of LBPs and their related products is imperative for ensuring their efficacy and safety. The bioactivities of polysaccharides are closely associated with their physicochemical properties, which can be easily monitored via chemical techniques. Therefore, analysis of physicochemical properties is a more straightforward and viable approach for the quality control of polysaccharides.Scope and approachIn this review, special techniques for the structural characterization of LBPs are summarized and discussed. In addition, quality evaluation approaches of LBPs that have never been emphasized are highlighted herein. Furthermore, industrial applications of LBPs are reviewed and discussed.Key findings and conclusionsHigh-performance anion-exchange chromatography coupled with pulsed amperometric detection is one of the most effective techniques for analysis of both acidic and neutral LBPs. Size-exclusion chromatography coupled with multi-angle laser light scattering and refractive index detection is able to determine absolute molecular weights, chain conformations, and contents of LBPs. Fingerprinting analysis and saccharide mapping analysis are effective approaches for quality evaluation of LBPs. However, the lack of appropriate quality evaluation approaches indicates an unreliable regulation of LBPs and their related products. This reveals the deficiency in the quality control of commercial products. Thus, the development of reliable approaches for pharmacological activity-based quality control of LBPs and their related products must be extensively investigated.     

Modelling the disruption of essential oils glandular trichomes with compressed CO2

A theoretical model is proposed for the evaluation of the disruption efficiency of essential oils glandular trichomes (glands) with compressed CO₂. The disruption of glands occurs during the fast decompression of the bed of herbaceous material. The glands are described as closed structures slightly permeable to CO₂. When exposed to compressed CO₂, the gas slowly penetrates the glands and dissolves in the intraglandular oil until the solubility limit is reached. During the fast decompression of the bed, the dissolved gas is desorbed from the oil phase and discharged to the bulk solvent. The inability of the glands to discharge the gas, at a rate dictated by the loss of solubility in the oil with the decompression of the bed, generates a pressure gradient across the glands that may lead to its rupture. In the present model, the excess pressure is described by an equation similar to Hagen–Poiseuilles formula for viscous flow due to a pressure gradient. The maximum pressure gradient across the glands during the fast decompression of the bed is then used to calculate the percentage of glands disrupted (efficiency of disruption) assuming a normal distribution of the bursting pressures of the glands. The model was applied to experimental results where the effects of pre- and post-expansion pressure, exposure time to pre-expansion pressure and the rate of decompression were investigated. Predictions of the model are also presented.     

采后处理与贮藏条件对柑贮藏效果的影响

通过对椪柑贮藏历年来的相关实验研究,即预贮、包装等不同的采后处理方法并结合砃峦ǚ缈夂屠淇庵兄?藏结果观测比较,找出了不适宜椪柑果实贮藏的采后处理方式和利于其贮藏的某些方法、设施。常温通风预贮预冷显著好于冷库冷风预冷;无论在常温通风库还是冷库中贮藏75d以上,单果包装均显著好于打蜡处理。正交实验进一步明确了包果袋宜薄不宜厚,预贮时间较长为宜。     

包装膜透性对西兰花采后冷藏品质变化的影响

本文研究了具有不同氧气（O2）和二氧化碳（CO2）透过率的包装膜对西兰花采后自发气调包装保鲜过程中包装袋内气体成分及西兰花贮藏品质变化的影响。采用预冷后的新鲜西兰花,经4种不同O2和CO2透过量的聚乙烯薄膜密封包装,包装袋尺寸为30 cm×25 cm,调查了不同包装处理在1±0.5 ℃下冷藏60 d包装袋内气体成分、组织电导率、色差、感官指标、Vc和叶绿素指标的变化情况。结果表明,在本试验条件下,不同O2和CO2透过率的包装膜对包装袋内气体成分、色差L*值和西兰花贮藏品质及货架期具有显著影响（p<0.05）。其中,O2和CO2透过率分别为16398.3 cm3/m2?24 h?0.1 MPa和68644.9 cm3/m2?24 h?0.1 MPa的包装膜从贮藏第1 d开始即可维持包装袋内O2（11.86~15.78 kPa/500 g）和CO2（2.61~4.25 kPa/500 g）水平达到相对稳定状态,直至贮藏期结束袋内西兰花仍保持较好的新鲜度和总体感官品质。     

First survey on the presence of ochratoxin A and fungi in raw cereals and peanut available in the Republic of Niger

Eighty one (81) samples of cereals (rice, maize, sorghum, millet) and peanut purchased from six local markets of Niamey city (Republic of Niger) were analyzed for the presence of fungi and ochratoxin A (OTA). Samples were microbiologically analyzed for determination of fungi. For OTA analysis, samples were extracted with methanol with an Ultra-Turrax homogenizer. OTA was then identified and quantified by using liquid chromatography (LC) with fluorescence detection. The confirmation of OTA identity in positive samples was confirmed by methyl ester derivatization.Analytical results showed that samples were contaminated with a large number of fungi, the most important genus are Aspergillus spp. (63%) followed by Fusarium spp. (9.7%) and Penicillium spp. (3.3%). Mycotoxin analysis showed that OTA was present in 85.7, 9 and 2.6% of peanut, rice and maize, respectively. The frequency of contamination of total analyzed samples was 9.8%. Levels of OTA in positive samples ranged between 0.1 and 4.9 ng/g. The average contamination of cereals samples with OTA was 3.7 ng/g. The high level value of OTA (4.9 ng/g) was found in a peanut sample commercialized in “Wadata market” of Niamey city. The present paper is the first ever drafted on the natural occurrence of OTA and fungi in cereals and peanut consumed in Republic of Niger.