Development of Optimized Edible Packaging Based on White-cheek Shark (Carcharhinus dussumieri) Skin Gelatin Biopolymer: Mechanical,Water Vapor Permeability,and Structural Properties

White-cheek shark skin gelatin (WSG) edible films were optimized with respect to their barrier, mechanical, and structural properties using response surface methodology (RSM), with the introduction of gelatin concentrations (1–4% w/v based on film forming solution) and glycerol contents (15–35% w/w based on gelatin weight) as the independent variables. WSG films with moderate levels of glycerol had higher tensile strength (TS), elastic modulus (EM), and elongation at break (E@b) depending more significantly on gelatin content. Adding higher levels of glycerol, film roughness was observed to decrease exponentially but water vapor permeability (WVP) increased linearly. Structural analysis using Fourier transform infrared spectroscopy (FTIR) showed more aggregated protein structures at higher gelatin content, which could be strongly related to the notable increase of contact angle. According to the model, the optimum conditions for the WSG film formula were found to be 3.3% WSG and 19.3% glycerol, giving a predicted maximum E@b, TS, EM, roughness, and contact angle of 183%, 4.4 MPa, 92 MPa, 4.93 nm, and 101°, respectively, with a predicted minimum WVP of 11.8 g.mm/day.m².kPa.     

Gelatin Films Containing Hydrolysates from Whitecheek Shark (Carcharhinus dussumieri) Meat

The effect of adding different concentrations of freeze-dried (FD-WCPH) and spray-dried (SD-WCPH) whitecheek shark (Carcharhinus dussumieri) protein hydrolysate to the physical properties (solubility in water, contact angle, water vapor permeability, and opacity), mechanical properties (tensile strength, elongation at break, and elastic modulus) and color of gelatin films has been studied. The results showed that FD-WCPH and SD-WCPH led to an increase in water solubility and water vapor permeability and a decrease in contact angle and opacity of gelatin films (P < 0.05). Fish protein hydrolysate concentration showed a linear relation with elongation at break and an inverse relation with the tensile strength and elastic modulus of the films (P < 0.05).     

大豆分离蛋白凝胶稳定性智能决策支持系统

影响大豆分离蛋白凝胶稳定性的因素有很多,为了准确地确定大豆分离蛋白适宜的凝胶条件,研究并设计了大豆分离蛋白凝胶稳定性的智能决策支持系统。在对系统目标、系统功能和系统结构分析的基础上,设计了基于事例和模糊ARTMAP神经网络的混合推理策略,有效地提高了推理的准确度和效率。系统具有较好的实用价值。     

Permeability of plastic films to methyl bromide: a comparative laboratory study

The permeability of plastic films to the fumigant methyl bromide (MB) was measured by two different methods, in order to facilitate the selection of films which are impermeable to the gas. Polyethylene-based films are highly permeable to MB, as evidenced by both methods. In contrast, multilayer coextruded films which have a layer of barrier material such as polyamide (PA) or ethylene-vinyl alcohol copolymer (EVOH) were significantly less permeable to MB, as reflected by the parameters permeability rate, time to 90% concentration (TC₉₀, by the diffusion method) and lag-time values (by the variable-volume method). A significant correlation was found between the permeability rate assessed by the diffusion method and that obtained with the variable-volume method. Permeability of all films increased with temperature as evidenced by all tested parameters. This increase was more pronounced with polyethylene films, the permeabilities of which increased five- to six-fold when the temperature was increased from 20°C to 60°C. The effect of temperature on barrier-film permeability was less significant. Permeability of films to MB was affected by additional factors such as additives, the length of the monomer side-chain, and the thickness and density of polyethylene films. © 1998 SCI     

影视资源在高校思想政治教育中的价值和应用研究

党的十八大以来，习近平总书记高度重视高校思想政治工作。大学生是高校思想政治教育的主要对象，媒介尤其是影像媒介对大学生的影响日益突出。在高校思想政治教育中加强以优秀主旋律影视作品、校园院线等为代表的影视资源运用，是让思想政治教育深入学生生活、走进学生心灵的有效途径。高校思想政治教育应高度重视挖掘影视资源独特的"以文化人"价值，在高校思想政治理论课教学、课外隐性思想政治教育、校园文化建设等方面充分应用影视资源铸魂育人。     

好莱坞电影：美国文化霸权的介质

随着全球化的日益深入，电影作为最国际化最活跃的媒介产业在美国全球化战略中扮演着向世界传递美国意识形态、价值观念和生活方式的重要角色，在全球范围内构筑起新一轮的“文化霸权”景观。通过对好莱坞电影的文化霸权现象、电影背后的深层话语及“他者”文化进行解读，探讨这种文化霸权带来的影响及世界电影的发展走向。     

原位酶谱技术分析旱地长期覆盖下根际酶活性空间分布

根与土壤微生物产生的酶是土壤有机质分解的主要生物驱动因素，对土壤养分循环具有重要意义。该研究利用原位酶谱技术在不破坏作物根系的同时，研究了渭北旱塬长期覆盖春玉米根际土壤酶活性空间分布。田间试验于2020年6月在中国科学院长武黄土高原农业生态试验站进行。以春玉米"先玉335"为供试材料，采用完全随机区组设计，设置秸秆覆盖（SM）、地膜覆盖（FM）和无覆盖（CK）三个处理，于春玉米吐丝期获取根系剖面酶谱图，分析了β-葡萄糖苷酶和亮氨酸氨基肽酶在春玉米根际的分布。结果表明：β-葡萄糖苷酶在秸秆覆盖下根际活性分布（热点）面积最大，是地膜覆盖的1.9倍、无覆盖的8.1倍；同时其在秸秆覆盖下延根分布距离最长为2.5 mm；与之对应，动力学拟合结果也表明秸秆覆盖下的酶动力学参数酶活最大反应速率和米氏常值最大，其土壤底物周转时间最快。亮氨酸氨基肽酶在地膜覆盖下活性分布总面积最大，是秸秆覆盖的1.8倍、无覆盖的6.4倍；其在地膜覆盖下酶活性延根分布距离最长为4.5 mm，秸秆覆盖下的酶动力学参数也为最大，底物周转时间最快。研究揭示了地表覆盖通过调节作物根际土壤酶活性空间分布促进养分吸收，实现旱地玉米高产高效的酶动力学机制。     

降解周期可调控的甘蔗渣生物降解地膜增温保墒性能分析

针对云贵高原地区春季播种时存在季节性干旱的问题，使用塑料地膜容易导致农田土壤污染的现状，该研究采用Box-Behnken设计试验，将施胶剂成分的硅酸钠、可溶性淀粉、硅油含量作为因变量，将降解率、抗张强度、土壤温度、土壤水分作为响应值，制备了一种降解周期可调控增温保墒甘蔗渣生物降解地膜。以不覆膜作为对照组（CK），探讨生物降解地膜的降解性能、抗张强度及对土壤水分和温度的影响，并观察降解过程中地膜纤维结构的变化。结果表明，地下覆膜的降解速度和降解强度均高于地表覆膜，覆膜72 d时，二者的降解率最高分别达86.41%、70.44%。在覆膜72 d时，地表试验组抗张强度下降到9.77～21.97 N/m，地下试验组在49 d后抗张强度接近为0；扫描电镜观察到地膜出现断裂的短纤维，与降解过程中地膜宏观表现出的膜片出现孔洞、质量逐渐下降规律一致。与CK相比，覆膜对提高土壤早间、午间、晚间温度均具有显著作用（P<0.05），且所有试验组对提高土壤含水率均有显著影响（P<0.05）。综上，甘蔗渣生物降解地膜的增温、保墒性好，为农业生产上推荐适宜的地膜组成及含量以指导生产实践具有较好的应用价值。