Preparation of TiO<Subscript>2</Subscript>-coated ZnO Nanoparticles and Their Effect on the UV Absorption of a Poly(vinyl alcohol) Composite Film

Titanium oxide (TiO₂) and zinc oxide (ZnO) composite structured nanoparticles were prepared by combining a sol-gel process and a solvothermal method. Titanium (IV) isoproxide (TTIP), used as a TiO₂ precursor, was dissolved in a colloidal ZnO nanoparticle solution synthesized by the sol-gel method, and TiO₂ was synthesized via solvothermal synthesis onto the ZnO nanoparticles. The effects of reaction conditions such as pH, reaction temperature, and reaction time on the morphology of the composite nanoparticles and the ultraviolet (UV) absorbance of their polymer composite films were investigated. The UV absorption of the poly(vinyl alcohol) (PVA) composite film with TiO₂-coated ZnO nanoparticles was higher than that of the TiO₂, ZnO, and ZnO-coated TiO₂ composite films. The reaction pH was found to have the strongest influence on the UV absorbance of the PVA/(TiO₂/ZnO) composite film. A pH of 7.0, reaction temperature of 250 °C, and reaction time of 24 h were the optimum conditions for UV absorption.     

茶多酚-壳聚糖复合膜的制备及保鲜效果研究

本研究以聚乙烯醇（PVA）和壳聚糖（CTS）为基材,甘油作为增塑剂,以茶多酚（TP）为功能性添加剂制备无污染、可降解且具有抗氧化功能的活性包装材料TP-CTS/PVA复合膜,分析TP浓度对复合膜机械性能、抗氧化能力、抑菌能力等理化性质的影响,研究复合膜与包装相关性能的影响,以期提高复合膜的综合性能。将其应用于圣女果的保鲜,测定其在贮存期间理化指标及微生物指标,进一步将不同TP浓度的复合膜涂抹于新鲜圣女果表面,分析圣女果在贮存期间的感官品质、腐烂率、失重率、可溶性糖、可滴定酸等指标的变化,系统研究复合膜对圣女果的保鲜效果。结果表明：以TP为功能性添加剂共混CTS和PVA制备的复合膜兼具抗氧化和抑菌效果;随着TP浓度增加,复合膜的颜色逐渐变深,TP浓度为1.5%时,复合膜的水溶性最低(19.85±0.64)%,此时复合膜的抗张强度呈最大值(13.19±0.77)MPa;当TP浓度增大,其对Escherichia coli和Staphylococcus aureus的抑菌能力也不断增强,能有效抑制细菌生长; TP浓度为2.0%时,复合膜对DPPH自由基清除率达到最大值(38.53±0.91)%;采用复合膜涂覆对圣女果能减少水分蒸腾、延缓果蔬机体衰老从而起到良好的保鲜效果,涂膜能有效延缓圣女果的腐烂和失水变质的现象,表明TP-CTS/PVA复合膜能改善果蔬的保鲜货架期和商品价值;在相同贮存时间内,当用TP浓度为1.50%复合膜涂抹圣女果时,圣女果的感官评价得分、失重率、腐烂率、可滴定酸含量、可溶性糖含量等各项指标较其他TP浓度试验组效果更好。研究表明,当TP浓度为1.5%~2.0%时制备的TP-CTS/PVA复合膜其抑菌性、耐水性、抗氧化性、以及保鲜性能等各项指标较为均衡,将其实际应用于生产中可根据需求调整TP浓度。本研究目的为探索开发抗菌抗氧化功能型复合膜和功能型包装材料替代塑料包装材料的可能性,为同时解决食品保鲜与环境污染问题提供依据。     

Development of UV Protective,Superhydrophobic and Antibacterial Textiles Using ZnO and TiO<Subscript>2</Subscript> Nanoparticles

In this research work, multifunctional cotton fabric comprising of UV protection, superhydrophobicity and antibacterial activity has been developed using facile pad-dry-cure method. In the first step, the concentration of repellent chemical has been optimized. Then, formulations containing nanoparticles of ZnO or TiO₂ along with optimized concentration of repellent chemical and organic-inorganic binder have been applied to cotton fabric followed by the evaluation of functional properties. The surface morphology and elemental composition of treated fabric has been characterized through SEM and EDX, respectively. The treated samples have shown promising UV protection, superhydrophobicity and antibacterial properties durable upto 20 washing cycles.     

The effects of UV irradiation exposure on the structure and properties of polypropylene/ZnO nanocamposite fibers

Unfilled polypropylene and polyropylene/ZnO nanocomposite fibers were produced using a melt spinning apparatus; then the fibers were exposed to UV irradiation. The structure and properties of the fibers were examined using scanning electron microscopy, tensile measurements, wide angle X-ray diffraction (WAXD), Fourier transform infrared (FTIR) spectroscopy, birefringence measurements and differential scanning calorimetry (DSC). Following 150 hours of exposure to UV irradiation, some transverse cracks on the surface of unfilled polypropylene fibers were observed. It was observed that both carbonyl and hydroperoxide indexes, which are the criteria for the detection of UV degradation of the fibers, were increased due to the increase in the UV irradiation exposure time and the increase in these indexes was smaller for nanocomposite fibers than those of unfilled Polypropylene fibers. It was also observed that crystallinity, crystallite size and total molecular orientation of UV irradiated nanocomposite fibers were increased in comparison with non-irradiated nanocomposite fibers. It was also found that the extent of increase in molecular orientation of the fibers was higher comparing to that for the nanocomposite fibers due to the UV irradiation exposure for the unfilled polypropylene fibers. Tensile properties of both unfilled and nanocomposite fibers were decreased after UV irradiation; this reduction correlated with the extent of the increase in molecular degradation of the fibers, as determined by measuring carbonyl and hydroperoxide indexes.     

甘蔗光降解地膜在湛江蔗区的增产效应及其降解效果

对甘蔗光降解地膜在湛江蔗区推广的增产效果及地膜残留状况等进行调查.结果表明:使用光降解地膜完全代替普通地膜,不会影响甘蔗苗期生长和产量;光降解地膜当年的残膜减少量在7.58%～16.77%:连续多年使用光降解地膜的蔗田地膜残留量明显低于普通地膜,且光降解地膜残留与盖膜次数呈显著负相关.在湛江冬春季,光降解地膜残膜露光1个月后就开始光降解,露光2个月后就基本破碎.     

SPI/HA/CMC三元复合膜的制备及其性能研究

以甘油为增塑剂,通过溶液共混法制备大豆分离蛋白/透明质酸/羧甲基纤维素钠三元复合膜,并采用SEM、UV-Vis、拉伸试验等手段对其微结构和性能进行了研究。结果表明:当SPI含量在40%~50%时,复合膜的力学强度最大,SPI的引入能够提高复合膜表面的疏水性,同时透光率也会降低。当SPI含量较低时,水蒸气透过率较低,当SPI含量超过50%时,水蒸气透过率显著增加。该复合膜以天然高分子为基质,具备良好的力学性能、耐水性、阻隔性,有望应用于食品包装领域。     

覆膜栽培对抗氧化花生的影响研究

引进高抗氧化花生品种(AQ),研究了覆膜栽培对其产量和品质的影响。结果表明:地膜覆盖能提高全生育期的叶面积指数,对干物质积累量的增加有促进作用。可促进花生提前出苗、开花、苗期早发稳长,单株饱果数、结果枝数、百果重和单株生产力增加,秕果数减少。产量和品质都比露地栽培有所提高。     

地膜覆盖和保水剂对甘蔗生长及产量的影响

设保水剂、地膜覆盖及只淋等量清水为对照3个处理,测定对甘蔗农艺性状及经济效益的影响。结果：从蔗茎产量分析,保水剂及地膜覆盖分别比对照增8985kg/hm2、8415kg/hm2,分别增9.8%、9.2%;从含糖量分析,保水剂及地膜覆盖分别比对照增1396.5kg/hm2、1246.5kg/hm2,分别增10.8%、9.6%;从经济效益分析,保水剂及地膜覆盖分别比对照增3592.5元/hm2、3427.5元/hm2,分别增7.84%、7.48%。结论：保水剂对甘蔗生长及产量有促进作用,且成本低,效益高,值得推广应用。     

高温胁迫对小麦蛋白质和淀粉品质影响的研究进展

灌浆期高温胁迫是导致小麦产量降低和品质变劣的主要生态因子之一,严重影响小麦生产的稳定性。本文综述了生育后期高温胁迫对小麦籽粒蛋白质数量和质量、淀粉含量和组成的影响以及导致品质变异的遗传、生理生化和分子生物学方面的最新研究进展。加深小麦品质变异分子机理的研究将有助于培育品质稳定的品种,提高对品质稳定性的控制能力。     

紫外诱变对黑曲霉降解氯嘧磺隆能力的影响

采用紫外(UV)诱变方法对黑曲霉进行诱变,用高效液相色谱法测定菌株对氯嘧磺隆的降解率,系统研究了黑曲霉经紫外诱变后对氯嘧磺隆降解能力的影响。结果表明:经紫外(UV)诱变黑曲霉总变异率随UV强度和辐照时间的不同而不同,受时间影响较大,对黑曲霉最佳的紫外(UV)诱变条件为UV强度30 W、辐照时间150 s,此条件下黑曲霉的正变率为35.16%;紫外(UV)诱变可以显著提高黑曲霉降解氯嘧磺隆的速度,在UV强度30 W、时间150 s时黑曲霉对氯嘧磺隆的降解速度最大,氯嘧磺隆半衰期为7.76 h比原始菌株(24.86 h)缩短17.1 h。最终筛选出降解能力提高最显著的菌株H1,其降解能力比原始菌株提高73.16%,且连续培养10代后降解率均在89%左右,降解性能及生长速度稳定,可以稳定遗传。     

Preparation of ZnO nanoparticles and nanofibers and their use in the degradation of rhodamine B dye under UV irradiation

ZnO nanoparticles (ZNPs) were obtained via a direct calcining method. ZnO nanofibers (ZNFs) were fabricated by electrospinning polyacrylonitrile (PAN) and zinc acetate (Zn(Ac)₂) solution and calcining PAN/Zn(Ac)₂ nanofibers. The samples were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), photoluminescence spectra (PL) and UV-vis spectroscopy. The results showed that the sizes of the ZNPs ranged from 90–275 nm with the average value 170 nm. The ZNFs were constructed by a series of nanoparticles along the fiber axis, and the sizes of the nanoparticles ranged from 50–250 nm with the average size 150 nm. The ZNPs and the ZNFs were both crystallized with hexagonal wurtzite structure. Although the nanoparticles in the ZNFs accumulated along the fiber axis and more surface oxygen vacancies were formed for the ZNPs, the distance of photocatalytic activities between these two kinds of catalyst was only 5 %. Besides, both the ZNPs and the ZNFs could be recycled and reused for their stable photocatalytic activities. Compared with the ZNPs, the ZNFs showed a wider application for their fibrious morphology.     

酸性电解水结合复合膜对橘柚保鲜效果的研究

为了防止橘柚采后枯水腐烂,采用酸性电解水浸果处理,并结合海藻酸钠、羧甲基纤维素钠、茶多酚、抗坏血酸配制成的复合保鲜剂进行涂膜处理后,将橘柚果实置于温度为(8±1)℃、湿度为75％～80％的条件下存放120 d,以好果率、失重率、细胞膜透性、可滴定酸度、可溶性固形物以及类胡萝卜素为指标进行保鲜效果的评价,通过正交试验确定...     

紫外线诱导对桦褐孔菌菌丝体生长及多糖含量的影响

用紫外线照射桦褐孔菌菌丝体,研究了不同照射时间对菌丝生长速度、菌丝生长势及多糖含量的影响。结果表明：紫外线照射对桦褐孔菌菌丝体的生长产生了不同程度的作用,其中以照射3min的处理组的作用最显著,与对照组有差异,促进了菌丝的生长;另以照射4min的处理组菌丝体干重最高为12．17g／L;以紫外线照射4min的处理组多糖含量最高,达到了2．39％。     

pH值和热处理对大豆肽稳定性的影响

分别采用Folin-酚法、SE-HPLC、火焰原子吸收分光光度法研究了pH值和加热处理对大豆肽的稳定性(包括溶解性、分子量分布、可溶性钙结合量)的影响.结果表明:在pH值3～11时对大豆肽的溶解性和分子量分布均无显著影响,pH值9时大豆肽的钙结合能力最大;高温热处理(温度为80℃、100℃)对大豆肽的溶解度无显著影响,但都不同程度的增加了大分子(>20 KDa)的相对含量,100℃时肽的聚合速度更快;80℃加热10 min提高了大豆肽的钙结合能力,热处理温度升高或加热时间延长均会导致钙结合能力的下降.     

氧化-生物双降解地膜在棉田示范效果

对氧化-生物双降解地膜在棉田应用示范的效果表明：氧化-生物双降解地膜降解效果明显,裸露部分降解率达57.57%;与普通地膜覆盖相比,覆盖该地膜能使棉株生长更加稳健,增加单株结铃及铃重,提高棉花产量,增产籽棉8.26%。     

不同颜色的地膜覆盖对马铃薯生长发育的影响

普通透明地膜已在我国农作物生产上普遍应用并明显地改变作物的生态环境,提高覆盖作物的产量和收益.但是透明地膜覆盖目前还存在着容易导致作物徒长、倒伏甚至早衰等现象,尤其是在杂草较多或覆膜质量不好时,膜下杂草丛生,形成"草棚",与作物争夺养分、水分,从而大大降低其使用效果.为了防治草害,覆膜前使用除草剂,又宜导致土壤污染、地下水污染、作物污染而恶化生态环境和降低作物的商品价值.     

生物降解膜对花生农艺性状和荚果产量的影响

为解决地膜"白色污染"问题,大田条件下,以普通地膜为对照,比较了4种生物降解膜覆盖对花生农艺性状及荚果产量的影响。结果表明,与普通地膜相比,生物降解膜A和B覆盖处理花生出叶速度放缓、侧枝数减少、荚果饱满度下降、产量降低;C1和C2膜覆盖处理,叶龄数、侧枝数干物质累积及荚果产量和普通地膜覆盖处理差异不显著;4种生物膜的降解效果比较,C2膜7月初花生盛花期开始出现裂纹,8月初进入开裂期,而其他降解膜几乎没有降解。由以上可看出,C2膜生物降解性比较好且花生荚果产量比对照不降低,为较适宜的降解膜。     

不同气候条件下片烟醇化效果的研究

为研究陕西不同地域气候条件对烟叶醇化质量的影响,以陕南和陕北烟厂存放的云南曲靖、陕西商洛片烟为试验对象,从片烟外观、感官评吸、化学成分三个方面验证片烟醇化效果.结果表明:(1)在外观质量上,陕南醇化的片烟比陕北醇化的烟叶颜色转深明显,油润感好;(2)在感官评吸质量上,陕南醇化烟叶香气质、刺激性和杂气指标好于陕北醇化烟叶,香气量、浓度差异不明显,陕北醇化烟叶的劲头略大于陕南醇化烟叶.(3)化学成分上,陕南醇化烟叶总糖含量高于陕北醇化片烟,烟碱和氯元素含量低于陕北醇化烟叶,其他化学指标变化不明显.(4)试验表明在两年醇化期内陕南醇化片烟的质量整体上好于陕北醇化烟叶.     

覆膜穴播方式对旱地小麦田土壤硝态氮和铵态氮积累的影响

为明确全膜覆土穴播栽培方式下旱地小麦土壤氮素的转化规律,采用比色法测定了全膜覆土穴播、传统地膜穴播和露地穴播冬、春小麦苗期、拔节期和收获期土壤硝态氮和铵态氮的含量。结果表明,在一次性基施氮肥后的第3年,0~60cm土层硝态氮累积量随土层深度的增加呈逐渐降低趋势,硝态氮大部分累积在土壤中下层(80~160cm)。随着春(冬)小麦的生长发育,各处理土壤硝态氮含量均呈"S"型变化,在120~160cm土层会出现一高峰值。相比露地穴播,全膜覆土穴播和传统地膜穴播能更好地利用0~80cm土层硝态氮。铵态氮含量在耕层土壤中较高,且随着土壤深度的增加而逐渐降低。全膜覆土穴播和传统地膜穴播减少了春(冬)小麦各生育时期0~60cm土层的铵态氮含量。     

Loading Effect of Chitosan Derivative Nanoparticles on Different Antigens and Their Immunomodulatory Activity on Dendritic Cells

Drug carrier nanoparticles (NPs) were prepared by the polyelectrolyte method, with chitosan sulfate, with different substituents and quaternary ammonium chitosan, including C236-HACC NPs, C36-HACC NPs, and C6-HACC NPs. To evaluate whether the NPs are suitable for loading different antigens, we chose bovine serum albumin (BSA), ovalbumin (OVA), and myoglobin (Mb) as model antigens to investigate the encapsulation effect of the NPs. The characteristics (size, potential, and encapsulation efficiency) of the NPs were measured. Moreover, the NPs with higher encapsulation efficiency were selected for the immunological activity research. The results showed that chitosan derivative NPs with different substitution sites had different loading effects on the three antigens, and the encapsulation rate of BSA and OVA was significantly better than that of Mb. Moreover, the NPs encapsulated with different antigens have different immune stimulating abilities to DCS cells, the immune effect of OVA-coated NPs was significantly better than that of BSA-coated NPs and blank NPs, especially C236-HACC-OVA NPs. Furthermore, we found that C236-HACC-OVA NPs could increase the phosphorylation level of intracellular proteins to activate cell pathways. Therefore, C236-HACC NPs are more suitable for the loading of antigens similar to the OVA structure.