Preparation of Glutaraldehyde Cross-Linked Chitosan Beads Under Microwave Irradiation and Properties of Urease Immobilized onto the Beads

The glutaraldehyde cross-linked chitosan beads were prepared under microwave irradiation and urease was immobilized onto the beads. The activity and the yield of enzyme activity of the immobilized urease were 10.83 U/g carrier and 47.700, respectively. The optimum conditions of immobilization were 100 of glutaraldehyde volume fraction, 10 mg/g of urease/beads weight ratio, 24 h of the processing time and pH 6.5 of the reaction medium for immobilization. The properties of the immobilized urease were investigated and compared with those of the free enzyme. The optimum pH values were 6.5 and 7.0 for the immobilized and free urease, respectively. The optimum temperature was 60 ℃ for the free urease, while it shifted to 65 ℃ for the immobilized enzyme. The Michaelis constant Km was 9.1 mmol/L for the immobilized and 12.5 mmol/L for the free urease. The immobilized urease retained 4000 of its initial enzyme activity even after 10 repeated uses. The immobilized urease stored at 4 ℃ retained 4600 of its initial activity even after 35 d.

PREPARATION AND ADSORPTION OF THIOUREA MODIFIED GLUTARALDEHYDE-CROSSLINKED CHITOSAN RESINS

The preparation and adsorption of thiourea modified glutaraldehyde-crosslinked chitosan resin （Thio-chitosan） using cyanuric chloride as activator was studied. The adsorptive capacity of thio-chitosan with 15% apparent degree of crosslinking （DC, mass ration of glutaraldehyde to chitosan） to Cu（Ⅱ） was 160mg/g （dry weight）. The adsorption of Cu（Ⅱ） was correlated with Freundlich and Langmuir isotherm equation. Cu（Ⅱ） adsorbed on thio-chitosan column （ 1cm×10cm） was eluted with 0.5mol/L H2SO4, 6mol/L HCI and 3% thiourea solution with the recovery of 88.3%, 86.1% and 95.3%, respectively. The thio-chitosan resin can be applied to the separation and recovery of metal ions.

One-pot synthesis of a hierarchical microporous-mesoporous phosphotungstic acid-HKUST-1 catalyst and its application in the selective oxidation of cyclopentene to glutaraldehyde

A hierarchical microporous-mesoporous metal-organic framework of HKUST-l（Cu）-encapsulated phosphotungstic acid （HPW） material, referred to as HPWs@Meso-HKUST-1, is prepared by a one-pot synthesis method using cetyltrimethylammonium bromide as the supramolecular template. The addition of HPWs to the synthesis mixture of hierarchical porous HKUST-1 results in the direct encapsulation of HPWs inside the mesopores of the HKUST-1 structure, with a homogeneous distribution over the HKUST-1 crystals, which is confirmed by XRD, FT-IR, N2 adsorption, UV-Vis DRS, and TEM. FT-IR-CO adsorption experiments indicated that additional Lewis acid sites were present in the HPWs@Meso-HKUST-1 sample. The novel heterogeneous catalyst demonstrates excellent catalytic performance for the selective oxidation of cyclopentene （CPE） to glutaraldehyde CGA） using tert-butyl hydroperoxide and acetonitrile （MeCN） as the oxidant and solvent, respectively. The high activity of the catalyst is attributed to the mesostructure of the catalyst and the nature and appropriate abundance of the HPWs--being highly dispersed with the addition of Lewis sites. After a reaction for 36 h, the 30% wt% HPWs@Meso-HKUST-1 catalyst exhibits a CPE conversion of 92.5% and a high GA yield of 73%. Furthermore, the HPWs@Meso-HKUST-1 material is sufficiently stable to prevent the leaching of HPWs, and behaves as a true heterogeneous catalyst that can be repeatedly recycled without sustaining a loss of activity and selectivity in the selective oxidation of CPE.

基于ADE优化的IPMSM全速域无传感器控制

为了实现内置式永磁同步电机(IPMSM)全速域的无传感器控制和切换速域的平滑过渡,提出了一种基于自适应差分进化(ADE)算法优化的复合控制方法。分别在零低速域、中高速域采用旋转高频电压注入法和滑模观测器法来对电机转速和转子位置进行估算,并在切换速域采用基于ADE算法的权重系数优化法来实现上述两种控制方法的平滑切换,从而实现IPMSM全速域无传感器控制。仿真结果表明:提出的复合控制方法能够实现电机全速域的无感控制和切换速域的平滑过渡,且具有良好的稳定性。

Coating performance on glutaraldehyde-modified wood

Scots pine(Pinus sylvestris L.) panels were modified with glutaraldehyde(GA) to various weight percent gains and subsequently coated with several commercial coatings. The drying rate and adhesion of the coatings on the modified wood were measured; the coated/modified woods were exposed outdoors to analyze how the wood modifications influence the coating deterioration. The results showed that GA modification caused an increase in the drying rate of the waterborne coatings, but had no influence on drying of tested solvent-borne coatings. GAmodification did not change the dry adhesion but reduced the wood strength in a pull-off test. Wet adhesion of waterborne coatings was improved, while that of the solvent-borne coatings tended to be somewhat reduced. During 22 months of outdoor weathering, the coated/modified samples exhibited lower moisture content than the coated/unmodified samples, but GA modification didn't contribute a substantially synergistic effect with surface coatings on resistance to weathering.

A Facile Route for the Large Scale Fabrication of Graphene Oxide Papers and Their Mechanical Enhancement by Cross-linking with Glutaraldehyde

A facile route for the large scale production of graphene oxide(GO) papers and their mechanical enhancement has been presented in this work. The novel paper-like GO made from individual GO sheets in aqueous suspension can be achieved in large scale by a simple drop casting method on hydrophobic substrates.Significant enhancement in mechanical stiffness(341%) and fracture strength(234%) of GO paper have been achieved upon modification with a small amount(less than 10 wt%) of glutaraldehyde(GA). The cross-linking reaction takes place between hydroxyl groups on the surface of GO and aldehyde groups of GA, through forming hemiacetal structure, which can result in distinct mechanical enhancement of the GO papers.

儿童维生素AD滴剂,这样吃才对

众所周知,维生素A、D对孩子的生长发育至关重要。而补充维生素A、D,最好选择专门的维生素AD制剂,比如维生素AD滴剂。但许多家长对其又不甚了解,有诸多疑问。以下,笔者将一一进行解答。

Characterization of Tungsten-Based Catalyst Used for Selective Oxidation of Cyclopentene to Glutaraldehyde

Tungsten-containing hexagonal mesoporous silica （W-HMS） supported tungsten oxide catalysts （WOx/W-HMS） was prepared for the selective oxidation of cyclopentene with aqueous hydrogen peroxide to glutaraldehyde. X-ray diffraction （XRD） results indicated that the crystal form of the active phase （tungsten oxide） of the WOx/W-HMS catalysts was dependent on the W loading and calcination temperature. X-ray photoelectron spec- troscopy （XPS） analysis revealed that the dispersed tungsten oxides on the surface of W-HMS support consisted of a mixture of W（V） and W（VI）. It was found that a high content of amorphous W species in （5＋） oxidation state resuited in the high catalytic activity. When the W loading was up to 12% （by mass） or the catalyst precursor was treated at temperature of 623 K, the catalytic activity decreased due to the presence of WO3 crystallites and the oxidation of W（V） to W（VI） on the catalyst surface. Furthermore, NH3-temperature-programmed-desorption （NH3-TPD） analysis showed that the effects of W loading and calcination temperature on the acidity of the catalysts were related to the catalytic activity. A high selectivity of 80.2% for glutaraldehyde with a complete conversion of cyclopentene was obtained over 8%WOx/W-HMS catalyst calcined at 573 K after 14 h of reaction.

ADS-B信号在对流层大气波导中的传播性能

对流层大气环境存在特殊大气结构“大气波导”,可形成电波超视距传播或产生雷达盲区等。目前,通过雷达、GNSS信号等可以对大气波导进行一定程度的反演探测,但均存在一定的不足。ADS-B信号具有应用范围广、信号密度大、实时性高等特点,为此提出利用ADS-B信号受到不同大气环境影响后能量损耗不同的特点对ADS-B信号与对流层大气环境关联性进行分析研究。以武汉地区ADS-B信号数据为例,基于抛物方程传播理论对路径损耗进行仿真分析,并进行了实验验证。结果表明:ADS-B接收信号与仿真结果存在线性相关性并给出线性表述,为后续利用ADS-B信号反演大气波导提供参考依据。

星基ADS-B系统空天链路的建模与仿真

星基广播式自动相关监视(ADS-B,automatic dependent surveillance-broadcast)系统是一种新型的航空器监视技术,在未来空中交通管理系统中具有广阔的应用前景。为了深入研究星基ADS-B系统中航空器到卫星的空天链路通信性能,将专业软件Matlab和STK(system tool kit)有效联合,构建符合国际标准的星基ADS-B空天链路完整模型;通过离散事件动态交互模拟ADS-B消息的发送与接收全过程,最后统计得出体现星基ADS-B空天链路通信性能的消息识别概率(POI,possibility of identify)、消息检测概率(POD,possibility of detective)、信号接收功率、信号冲突概率、卫星覆盖范围等指标。仿真结果表明,随着区域内航空器数量上升,POI、POD下降,消息冲突概率上升。

Immobilization of laccase on amine-terminated magnetic nano-composite by glutaraldehyde crosslinking method

The immobilizing procedure has great influence on the activity of the immobilized laccase. The laccase was immobilized on copper tetraaminophthalocyanine (CuTAPc)-Fe3O4 magnetic nano-composite by glutaraldehyde crosslinking method via a two-step reaction. For 1 g nano-composite, the optimum pH value, the quantity, the concentration and reaction time of glutaraldehyde are 7.0, 10 mL, 10% and 4 h, respectively. In the second step the optimum pH value, reaction temperature and reaction time of laccase are 5.0, 0 ℃ and 2 h, respectively. The average diameter of the immobilized laccase is 78 nm, the saturation magnetization (Ms) of the immobilize laccase is 23.45 A·m2/kg and the surface area of the immobilized laccase is 115.03 m2/g. When 2.0 mg/mL laccase solution is used under optimum conditions and 2, 2′-azino-bis-(3-ethylbenzothiazoling-6-sulphonic acid) is used as substrate, the activity of immobilized laccase reaches 1 430 U/g (nano-composite) and the Michealis-Menten constant(Km) of the immobilized laccase is 2.38×10?5 mol/L.

基于迁移学习-元学习的ADS-B攻击分类研究

准确分类通航领域ADS-B攻击类型,采取预防攻击措施,对保障通航运行安全性具有重要意义。针对通航领域ADS-B攻击数据样本少,提出一种基于迁移学习-元学习的ADS-B攻击分类模型。该模型将迁移学习与深度卷积自编码器相结合,建立ADS-B攻击特征提取模型,提取数据样本的攻击有效特征表示,并运用元学习策略在特征空间中实现ADS-B攻击准确分类。实例研究表明,基于迁移学习-元学习的攻击分类模型可有效分类小样本ADS-B攻击,且正确率在95%以上。

The Stabilization Effect of Glutaraldehyde on the Spirulina platensis Phycobilisomes

The spectral properties of the glutaraldehyde-treated phycobilisomes were studied. The results showed that glutaraldehyde was effective in preventing phycobilisomes from dilution- induced dissociation and preserving the intra-phycobilisomes energy transfer.

Effects of albumin/glutaraldehyde glue on healing of colonic anastomosis in rats

To evaluate the effect of local surgical adhesive glue (albumin/glutaraldehyde-Bioglue) on the healing of colonic anastomoses in rats. METHODSForty Albino-Wistar male rats were randomly divided into two groups, with two subgroups of ten animals each. In the control group, an end-to-end colonic anastomosis was performed after segmental resection. In the Bioglue group, the anastomosis was protected with extraluminar application of adhesive glue containing albumin and glutaraldehyde. Half of the rats were sacrificed on the fourth and the rest on the eighth postoperative day. Anastomoses were resected and macroscopically examined. Bursting pressures were calculated and histological features were graded. Other parameters of healing, such as hydroxyproline and collagenase concentrations, were evaluated. The experimental data were summarized and computed from the results of a one-way ANOVA. Fisher’s exact test was applied to compare percentages. RESULTSBursting pressures, adhesion formation, inflammatory cell infiltration, and collagen deposition were significantly higher on the fourth postoperative day in the albumin/glutaraldehyde group than in the control group. Furthermore, albumin/glutaraldehyde significantly increased adhesion formation, inflammatory cell infiltration, neoangiogenesis, and collagen deposition on the eighth postoperative day. There was no difference in fibroblast activity or hydroxyproline and collagenase concentrations. CONCLUSIONAlbumin/glutaraldehyde, when applied on colonic anastomoses, promotes their healing in rats. Therefore, the application of protective local agents in colonic anastomoses leads to better outcomes.

基于多时间特征融合网络的ADS-B实采信号分离

不同于以往单天线广播式自动相关监视(Automatic Dependent Surveillance-Broadcast,ADS-B)信号分离中利用仿真的ADS-B信号制作数据集,将单天线接收的真实飞机发射的ADS-B原始信号通过调整信号起始时间以及功率并人为增加噪声来制作数据集。为了提高信号分离的时域波形精度,提出一种多分辨率多时间特征融合重采样(Multi-Temporal fusion Resampling of Multi-Resolution Features,MTRM-RF)网络,通过卷积将信号转化成不同采样率的信号并分别使用多层堆叠逐渐膨胀的一维卷积提取不同时间间隔的特征,以获得更多的时间信息。对多种基于深度学习的语音分离网络进行比较发现,MTRM-RF网络能够有效地融合ADS-B信号的不同采样率、不同时间间隔采样点的特征进行训练。并且随着训练集数据量的增加,分离信号的平均解码正确率达到88.39%,证明该网络可有效分离单天线实采的ADS-B交织信号。

Suture-Less Circumcision by Glutaraldehyde Albumin Glue Enhanced Laser Tissue Welding—A Comparative Study

Background: Suture-less circumcision by Feracrylate glue creates a weak and non waterproob bond. Hence, there is wound dehiscence and delayed healing which favor infection in many patients. I am describing a new technique for suture-less circumcision which is free from above limitations. Methods: In my center in the time span of 2 years, I did 51 cases of circumcision with Laser tissue welding technique (group A). Age range was 5 months to 21 years. During the same time span, in 56 patients circumcision was done by Feracrylate glue (group B). The age range was 3 months to 22 years. This group was kept as a control. Patients in both groups were randomly distributed. The technique of circumcision by Laser tissue welding is as follows. Patient is under short GA, the prepuce above the artery forceps is chopped off by scissors and bleeders are coagulated by bipolar cautery. Now, 0.9 ml 40% human albumin is taken in 1 ml syringe and mixed with 0.1 ml of 10% glutaraldehyde solution. The syringe is shaken vigorously to mix both the components. The skin and mucosa of penis are held by tooth forceps and a thin layer of this mixture is layered over it all around. Infrared Laser of 5 watts power and 850 nm illuminated over this bond for 60 seconds to polymerize it. Results: In group A, 2 (3.9%) patients developed partial wound gape, no patient had complete wound gape. 3 (5.88%) patients had grade 2 infections which settled with conservative treatment of oral antibiotics. In group B, 6 (10.71%) patients had partial wound gape and 8 (14.28%) patients had complete wound gapping. 11 (19.64%) patients developed grade 2 and 8 (14.28%) patients grade 3 wound infection. All these 19 patients’ post-operative antibiotics were started and given for 7 - 10 days. The Glutaraldehyde albumin mixture bond is already described in medical literature (Bioglue) for its use to seal coronary anastomosis after CABG operation, to seal sutures of cardiac surgery and for aortic dissection, etc. It is a surgical adhesive composed of purified bovine serum albumin (BSA) and glutaraldehyde and is already American FDA approved. It creates a flexible mechanical seal independently of the body’s clotting mechanism. In my technique, 0.9 ml of 40% human albumin is mixed with 0.1 ml 10% glutaraldehyde solution which costs only 50 cents which is a massive 1000 times cost reduction. Laser application polymerizes the glue and forms a waterproob bond in less than a minute. In my technique, percentage of glutaraldehyde used is only 10% compared to 50% in bioglue, hence it is non-toxic to the tissues. Conclusion: Suture-less circumcision by glutaraldehyde albumin glue enhanced Laser tissue welding is a safe, cheap and effective technique of performing circumcision. It is an important advance in circumcision surgery after a long time. The technique becomes a foundation for its vast application in other areas of surgery.

Influence of Glutaraldehyde on the Properties and Release Kinetic of α-Tocopherol from Chitosan-based Film

A crosslinked chitosan film with α-tocopherol was produced by a solution casting method. The appearance, mechanical properties, morphology, barrier properties and release kinetics of the α-tocopherol were evaluated. The addition of glutaraldehyde and α-tocopherol decreased the lightness and greenness and increased the yellowness of the chitosan-based film. Moreover, it also affected the compatibility of the film due to a decrease in the opacity values. The elongation at break(EB) and tensile strength(TS) values of the film decreased when the glutaraldehyde and α-tocopherol were added. In contrast, the Young’s modulus(YM) values increased. SEM micrographs showed coarse spots and pores on the surface and cross-section of the film when compared with the chitosan film. Based on the results, it was indicated that the chitosan structure was disconnected by the α-tocopherol, and the glutaraldehyde as a crosslinking agent generated a link between the chitosan network, which could be the cause of the reduced flexibility and the increased surface roughness of the film. However, the glutaraldehyde and α-tocopherol did not result in a significant difference in water vapour permeability(WVP) values. The glutaraldehyde influenced the release kinetics of the α-tocopherol as seen by the decrease of the diffusion coefficient values that were calculated using the Fickian diffusion model.

基于AD与TRIZ的加工中心主轴松拉刀机构优化设计

数控加工中心在加工过程中常出现主轴松刀力不足或无法松刀的现象。针对此问题,通过TRIZ系统组件分析明确现有松拉刀机构各组件间作用关系,利用因果链分析得出影响松刀的根本原因,最终应用TRIZ理论中的物场模型分析方法和AD独立性原理提出优化设计方案。根据新方案计算出实际工况下的主轴松刀力和螺杆强度,并对松刀杆进行建模和仿真。结果表明:最大位移量为6.995μm,最大应力为45.24 MPa,符合结构设计要求。最后,经过现场实物测试,当液压力为5 MPa时,松刀行程、松刀力以及打刀量均符合生产要求,验证了优化设计方案的合理性。

白菜型冬油菜BrADS2基因的克隆、表达分析与亚细胞定位

【目的】探究白菜型冬油菜(Brassica rapa L.)脂肪酸去饱和酶ADS2(Δ9 fatty acid desaturase)基因与抗寒性的关系。【方法】基于前期转录组结果,采用一步定向克隆法得到BrADS2基因;构建GFP融合表达载体,通过注射法在烟草下表皮细胞进行瞬时转化,同时采用农杆菌侵染法侵染‘中双11号’;利用qRT-PCR技术,检测抗寒性不同的白菜型冬油菜品种叶片中ADS2基因的表达模式,并对低温下冬油菜的形态变化和抗氧化酶活性、电导率含量进行分析。【结果】白菜型冬油菜BrADS2基因可编码307个氨基酸,该基因编码的蛋白具有亲水性特性;qRT-PCR结果显示,BrADS2基因的表达量呈先升后降的单峰型变化,且在-4℃时表达量达到峰值;亚细胞定位结果显示BrADS2蛋白在细胞质和细胞膜上表达;低温处理下3个品种叶片的相对电导率、抗氧化物酶活性均显著上升,强抗寒品种抗氧化酶活性高于弱抗寒品种,电导率却相反;农杆菌介导侵染‘中双11号’下胚轴后获得15株转基因阳性苗,且转基因油菜阳性植株叶中的BrADS2基因表达量均显著高于野生型。【结论】推测BrADS2基因在白菜型冬油菜膜脂不饱和调节中起重要作用,揭示了ADS2基因与冬油菜抗低温胁迫的关系。

基于改进型多斜Ⅲ技术的7位半AD转换器设计

高精度测试仪器在环境试验中扮演着重要角色,而积分型AD转换器被广泛的应用在高精度测试仪器中。针对传统型积分型AD转换器转换速率较低的问题,提出了一种提高转换速率的改进型多斜ⅢAD转换器,详细的介绍了其原理和设计思路。该转换器以单片机与CPLD一同控制积分型ADC,在积分末尾利用单片机片内ADC测量积分器的残留电压,以达到提高转换速率的目的。经理论分析该AD转换器比传统型转换速率快836倍,分辨率可达到31位,在±10V直流电压测量中可实现7位半分辨率。