Enhancement of Enzymatic Saccharification of Wheat Straw Residue by Ammonium Sulfite Pretreatment

Efficient utilization of wheat straw residue(WSR) from pulp mills is an important priority for the sustainable development of the pulp and paper industry. In this study, the effects of ammonium sulfite(AS) pretreatment with different AS charges(wt%) and pretreatment temperatures on the chemical composition and enzymatic hydrolysis of WSR were studied. The results revealed that more lignin was removed with the increase of pretreatment temperature and AS charge. The degradation of hemicellulose became severe at high pretreatment temperature, while cellulose remained stable during the pretreatment process. The enzymatic hydrolysis efficiency of pretreated WSR was increased and then decreased with the increase of the AS charge and pretreatment temperature. The AS charge exerts a stronger effect on enzymatic hydrolysis efficiency than the pretreatment temperature. Glucan and xylan conversion ratios up to 88.9% and 44.9%, respectively, were obtained. The highest total sugar conversion ratio was 67.0% when WSR pretreated with 16% AS at 165℃ was hydrolyzed with a cellulase loading of 40 FPU per gram of glucan.

A Fair Blind Signature Scheme to Revoke Malicious Vehicles in VANETs

With the rapid development of IoT(Internet of Things),VANETs(Vehicular Ad-Hoc Networks)have become an attractive ad-hoc network that brings convenience into people’s lives.Vehicles can be informed of the position,direction,speed and other real-time information of nearby vehicles to avoid traffic jams and accidents.However,VANET environments could be dangerous in the absence of security protection.Because of the openness and self-organization of VANETs,there are plenty of malicious pathways.To guarantee vehicle security,the research aims to provide an effective VANET security mechanism that can track malicious vehicles as necessary.Therefore,this work focuses on malicious vehicles and proposes an anonymous authentication scheme in VANETs based on the fair blind signature to protect vehicle security.

济南市6~18岁儿童青少年散光分布特征及矫正情况

目的:调查济南市6~18岁儿童青少年散光的流行病学分布,探讨该人群散光类型和程度的分布规律。方法:横断面调查研究。本研究于2021年10—12月对济南市12个区县1056所学校共1034863位中小学生进行视力及屈光筛查。采用满足GB/T1533的视力表检查视力,采用符合ISO0342要求的台式电脑验光仪对筛查学生进行非睫状肌麻痹下屈光检测,测量3次,取其平均值。年龄变化趋势采用Cochran-Armitage趋势检验,分类数据分析采用卡方检验。结果:最终纳入年龄6~18岁中小学生1016053人数据进行分析。济南市6~18岁学生散光患病率为48.8%,其中轻度散光率为25.9%,中度散光率为16.6%,重度散光率为6.3%。男生散光率为50.0%,女生散光率为47.4%。单纯左眼散光率(15.8%)明显高于单纯右眼散光率(7.3%),差异具有统计学意义(χ^(2)=15900,P<0.001)。双眼均散光率(25.7%)高于单眼散光率,差异具有统计学意义(χ^(2)=15940,P<0.001)。轻、中、重度散光率随年龄增长逐渐增高,差异有统计学意义(Z值分别为-82.8、-181.0、-91.3,均P<0.001)。顺规散光在不同性别、眼别中均占比最大,其中左眼顺规散光占比最大,为93.1%。顺规散光构成比中,男生高于女生,左眼高于右眼,但差异无统计学意义(P>0.05)。7岁之后,复合远视散光随年龄增长占比逐渐减少,差异有统计学意义(Z=-123.3,均P<0.001)。复合近视散光随年龄增长占比逐渐增大(Z=-82.9,均P<0.001)。散光总矫正率为46.1%。结论:散光在6~18岁人群中的发病率较高,各年龄组散光度分布均以低中度散光为主。不同分类中以顺规散光、复合近视散光为主。