有机磷水解酶生物传感器载体固定化酶的研究

有机磷水解酶（OPH）传感器作为检测农产品中农药残留的新型检测装置,其酶的固定化对OPH传感器的灵敏度和稳定性有重要的影响。研究了几种酶固定化载体、孔径大小、固定方式、固定方法（试剂组成）对传感器pH值的影响。结果显示：采用孔径为0.45μm的硝酸纤维素膜制备固定化酶片的pH值要大于其余几种;采用浸泡方式制备固定化酶片的pH值明显大于传统的滴定法;采用牛血清白蛋白（BSA）、戊二醛交联固定的效果优于酶直接吸附法和BSA固定法,且当戊二醛体积分数为2.5％,BSA为10％时,酶固定化效果最好。     

基于级联神经网络的蛋白质二级结构预测

为提高蛋白质二级结构预测的精度,提出一种由两层网络构成的级联神经网络模型。第1层网络采用具有差异度的5个子网构成的网络模型,对第2层网络的输入编码进行改进。对PDBSelect25中的36条蛋白质共6 122个残基进行测试,结果表明,该模型能有效预测蛋白质二级结构,其预测精度分别比SNN, DSC, PREDSATOR方法提高5.31%, 1.21%和0.92%,平均预测精度提高到69.61%。     

基于显著闭合边缘的图像检索方法

为提高基于内容的图像检索查准率,研究基于显著闭合边缘的图像检索方法.设计显著闭合边缘提取算法,利用人类视觉注意机制获取显著图,根据原始边缘图确定显著边缘图,连接显著边缘间的断裂,得到显著闭合边缘,结合边缘梯度和角度值的直方图实现图像检索.实验结果表明,该方法具有较高的查准率.     

The electrode/sample contact effects on the dielectric properties of the CaCu3Ti4O12 ceramic

In this paper, the contact effects at the electrode/sample interfaces on the dielectric properties of the CaCu₃Ti₄O₁₂ (CCTO) ceramic were studied. The experimental results provide clear evidence that the colossal dielectric constant in CCTO is related to the ceramic itself; however, it may also partly originated from the electrode/sample contact effects which depends on the surface resistivity of the sample. When the surface resistivity of the ceramic is as high as 1.2 × 10⁸ Ω cm, no obvious mobile space charges can be observed, and the dielectric properties of the sample is inert to the different metal electrodes and various sample thicknesses, indicating the colossal dielectric constant (near 2000 at 10 kHz) at room temperature is due to the true properties of the ceramic itself. However, after the surface resistivity is lowered to 3.1 × 10⁷ Ω cm through post-annealing the sample in N₂ atmosphere at 750 °C, obvious mobile space charges can be observed, and the dielectric properties of the sample become sensitive to the different types of contacts. The dielectric constant of the sample with Pt electrode shows a significant enhancement (up to 5000 at 10 kHz), comparing with that of the sample with Ag electrode. Clearly, in this case, the extrinsic contact contributes partly to the colossal dielectric constant of CCTO ceramic.     

Preparation and characterization of poly(N-isopropylacrylamide) films on a modified glass surface via surface initiated redox polymerization

A functionalization with 3-aminopropyltriethoxysilane (APTES) monolayer of a hydroxylated glass surface, followed by the surface initiated graft radical polymerization of N-isopropylacrylamide (NIPAm) using amino groups of APTES monolayer chemical bonded with glass surface and Ce⁴⁺ as a redox initiating system. The microstructure of poly(N-isopropylacrylamide) (PNIPAm) film obtained from the redox graft polymerization on the modified glass surfaces was examined by water contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM), and the results showed that about 60 nm thickness of thermosensitive polymer (PNIPAm) film successfully formed.     

Kidney bean (Phaseolus vulgaris L.) milk substitute as a novel plant-based drink: Fatty acid profile,antioxidant activity,in-vitro phenolic bio-accessibility and sensory characteristics

Recently, plant-based milk alternatives have gained popularity due to healthy food trends, sustainability concerns, and environmental repercussions. The current study is unique for the investigation of in vitro phenolic bioaccessibility, fatty acid composition, and sensory evaluation of plant-based milk from two different local kidney bean varieties grown in Turkey, oval and cherry. Kidney bean milk had 1.92–2.32% protein, which was slightly greater than other commercial plant-based milk alternatives. The majority of the fatty acids in the samples were α-linolenic acid (25.66–27.78%) and palmitic acid (18.95–23.08%). The total antioxidant capacity bio-accessibility of kidney bean milk was 154%–295% by cupric reducing antioxidant capacity (CUPRAC) and 50%–186% by α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging method while the total phenolic content bio-accessibility varied between 207%–266%. Overall acceptance of kidney bean milks varied between 2.9 and 4.1 out of 10. These findings presented that kidney bean milk is an alternative for the food industry with its rich bio-accessible antioxidant capacity and fatty acid profile although intense beany flavor detected during sensory analysis.     

Understanding the influence of PEF treatment on minerals and lipid oxidation of wet- and dry-aged venison M. longissimus dorsi muscle

Pulse electric fields (PEF) treatment can be used to improve meat quality attributes, such as tenderness and mass transfer kinetics of dry ageing of meat. This study investigated the effect of PEF (high-PEF 10 kV, 50 Hz, 20 μs; low-PEF 2.5 kV, 50 Hz, 20 μs) and ageing method (wet- and dry-ageing) on venison mineral profiles, and lipid and conjugated linoleic acid (CLA) oxidative stability. Twelve loins from six red deer were assigned to six groups: no-PEF dry-aged control, no-PEF control, wet-aged Low-PEF, dry-aged Low-PEF, dry-aged High-PEF, wet-aged High-PEF. Secondary oxidation products contents were not affected by PEF treatment (p > 0.05), but were affected by dry ageing (p < 0.05). CLA was stable across PEF treatments and different ageing regimes (p > 0.05). PEF treatments did not have any effect on minerals (p > 0.05). This study validates the safety of using PEF in venison processing with limited detrimental oxidative modifications.Industrial relevance - PEF treatment and the dry-ageing regimes applied to venison in the present study did not produce excessive oxidative by-products that could compromise product quality. The application of both PEF treatments (HPEF 10 kV, 50 Hz, 5 μs; LPEF 2.5 kV, 50 Hz, 5 μs) could potentially improve the drying of venison with a low risk of increasing oxidation.     

Afterglow of atmospheric non-thermal plasma for disinfection of lentil seeds from Botrytis Grey Mould

Seed-borne fungal diseases of grains are a serious threat to grain crops' yield due to lack of either resistant crop varieties or dependence on fungicides. Therefore, there is a growing demand to develop sustainable technologies for crop protection. In the present study, an atmospheric microwave plasma was employed to eradicate Botrytis cinerea from lentil seeds. Argon, air and a combination of them were applied to create the plasma. There was a 41% reduction in the percentage of artificially contaminated seeds (with an initial contaminated seed percentage of 95.8%) after 100 s treatment of 2.5 g of lentil seeds with the afterglow of air plasma followed by 24-h holding time. A 32.3% reduction occurred when a 30% air/70% Argon was applied for 10 s and 60 min of holding time. The holding time of 24 h increased catalase activity from 0.8 to 1.1 mM H₂O₂ mg⁻¹ min⁻¹ that was an indicator of early plant immune system fortification. This also changed seeds' colour toward redness and yellowness. Conclusively, the afterglow of microwave plasma could be considered as a part of integrated disease management in lentil crops.     

基于3维模型的数字浮雕生成技术

目的 浮雕是雕塑艺术的一种,根据其空间结构和用途的不同分为高浮雕、浅浮雕和凹浮雕3类。随着数字化技术和3D打印技术的发展,数字化浮雕的生成技术已经成为近年来计算机图形学领域的研究热点之一,从3维模型生成浮雕以其真实自然的效果成为浮雕生成的主要方法之一。为了使即将进入该领域的学者尽快了解该方法的现状和发展趋势,本文对3种类型的浮雕生成技术进行了系统的综述。方法 介绍了3种类型的浮雕生成技术,着重比较分析了基于3维网格模型的数字浅浮雕生成过程中的关键技术,存在问题及解决方案。针对复杂3维网格模型在生成数字凹浮雕过程中存在的部分细节信息丢失、特征线类型体现形式不完善、线条与形体间的过渡尚未解决、生成浮雕效果不自然等具体问题,提出了适用于3维复杂网格模型生成数字凹浮雕的研究方案。同时,从角色动画序列出发,对最优浮雕的生成技术进行了探讨,探讨结合信息熵理论计算选择最佳动作及观察视角的场景,还原艺术家的创作过程,为适用于面向3维打印的用户浮雕产品定制服务提供了可行的解决方案。结果 基于3维模型的浮雕生成方法是生成数字浮雕的一种重要方法,如何通过压缩和细节保持相关算法得到效果自然的浮雕模型一直是研究者们研究的热点问题。结论 虽然由3维模型生成数字浮雕是一种行之有效的方法,但是仍存在细节信息丢失、线条过渡不自然、特征线类型不完善等几个值得继续研究的问题,另外一个值得研究的问题就是如何智能地从3维动画序列生成浮雕。