Dual pH‐ and thermal‐responsive nanocomposite hydrogels for controllable delivery of hydrophobic drug baicalein

Hydrogels have been widely used as mild biomaterials due to their bio‐affinity, high drug loading capability and controllable release profiles. However, hydrogel‐based carriers are greatly limited for the delivery of hydrophobic payloads due to the lack of hydrophobic binding sites. Herein, nano‐liposome micelles were embedded in semi‐interpenetrating poly[(N‐isopropylacrylamide)‐co‐chitosan] (PNIPAAm‐co‐CS) and poly[(N‐isopropylacrylamide)‐co‐(sodium alginate)] (PNIPAAm‐co‐SA) hydrogels which were responsive to both temperature and pH, thereby establishing tunable nanocomposite hydrogel delivery systems. Nano‐micelles formed via the self‐assembly of phospholipid could serve as the link between hydrophobic drug and hydrophilic hydrogel due to their special amphiphilic structure. The results of transmission and scanning electron microscopies and infrared spectroscopy showed that the porous hydrogels were successfully fabricated and the liposomes encapsulated with baicalein could be well contained in the network. In addition, the experimental results of response release in vitro revealed that the smart hydrogels showed different degree of sensitiveness under different pH and temperature stimuli. The results of the study demonstrate that combining PNIPAAm‐co‐SA and PNIPAAm‐co‐CS hydrogels with liposomes encapsulated with hydrophobic drugs is a feasible method for hydrophobic drug delivery and have potential application prospects in the medical field. © 2018 Society of Chemical Industry     

ISO和API石油管标准最新动态（2015）

文章对美国石油学会2015年勘探与开发冬季标准化年会期间跟踪获取的ISO、API标准最新动态,重点对石油管相关的国际标准提案的进展情况进行了总结和介绍,为我国从事石油管科研、制造、使用和标准化工作的人员提供参考和启示。     

微量Y(0.2 wt.%)对铸造Mg-Sn合金热变形行为影响

采用MTS-CMT5105电子万能试验机,在温度为250~400℃、初始应变速率为10_-4~10_-1s_-1,最大变形量为40%的条件下,对铸态Mg-2.5Sn(wt.%)和Mg-2.5Sn-0.2Y(wt.%)合金进行压缩变形。结合真应力-应变曲线、峰值应力、显微组织、本构方程、DMM加工图,研究了微量Y(0.2 wt.%)对铸造Mg-Sn合金热变形行为的影响。结果表明：微量Y的添加,在较低应变速率时,会使Mg-Sn合金热压缩峰值应力增加30%以上;但在较高应变速率时,却对其影响不大。会改变合金塑性变形机制的控制方式,即由扩散控制变为位错的滑移和攀移。会抑制动态再结晶。会降低功率耗散系数,扩大加工失稳区。     

Synthesis of superabsorbent hydrogel and manganese dioxide nanowires composite for adsorption of Pb(II) from aqueous solution

The superabsorbent composite was prepared by aqueous solution polymerization, using manganese dioxide, acrylic acid, acrylic amide, 2‐acrylamide‐2‐methyl‐1‐propanesulfonic acid as raw materials, N,N′‐methylene bisacrylamide as cross‐linker, and K₂S₂O₈ as initiator. The composite was characterized by Fourier transform infrared spectrophotometer, thermogravimetric analysis and scanning electron microscopy analysis. This article also described the adsorption behavior of the superabsorbent composite with respect to Pb(II) removal from aqueous solution. The kinetic studies for Pb(II) adsorption showed that the pseudo‐second‐order adsorption mechanism was predominant. Moreover, adsorption isotherm data were reliably described by the Freundlich model. Regeneration of the adsorbent was attained by 0.1 mol L⁻¹ HCl. POLYM. COMPOS., 36:775–784, 2015. © 2014 Society of Plastics Engineers     

离子色谱法测定充气型(二氧化碳)饮用水中硝酸盐和硫酸盐的干扰及消除

本文研究了以离子色谱仪测定充气型(二氧化碳)饮用水中硝酸盐和硫酸盐时存在的干扰,并通过调节淋洗液浓度,对样品稀释、超声处理的预处理方式来消除干扰的效果。结果表明,测定充气型饮(二氧化碳)用水存在的干扰与游离二氧化碳含量有关。通过对样品超声处理15 min并稀释5倍上机,在淋洗液KOH浓度为13 mmol/L的分析条件下,可有效地消除干扰,改善分离度。离子浓度的相对标准偏差(RSD,n=5)在0.70%~2.21%之间,加标回收率在83.5%~109.2%之间。     

非饱和土边坡的监测和人工降雨试验

介绍了用于非饱和土边坡试验的人工模拟降雨设备的组成、主要设计参数和控制降雨强度的方法,着重介绍了总降雨量、径流量、孔隙水压力(吸力)、含水量4种基本数据测量所需的仪器及其埋设方法,给出应用实例和比较分析,并设计了在重庆某高速公路填土边坡上的非饱和土特性监测计划和人工降雨装置.     

华地组设计楼

本案地处广州市区较为繁华的天河北路,而在设计创作过程中需要宁静、简洁及自然的空间,因此营造一个平和、简朴甚至于冥想的氛围尤为重要。原粗批荡墙(面涂白色ICI)的质朴使用不仅降低了成本,同时也去除了奢华繁杂,使空间更开阔平静,     

The use of contact lenses among university students in Chengdu: Knowledge and practice of contact lens wearers

Purpose

To assess the prevalence and general knowledge of contact lens wearers among college students in Chengdu, a metroplolitan of Chinaand find out the routine habits of use and hygienic conditions when wearing contact lenses.

规划视觉:加拿大散记

1绿色国度 加拿大的四月,是冬去春来的季节.我们刚刚抵达多伦多的那几天,还感受不到一点春的气息.在城外,漫山遍野的枫树尚未发出新芽,枯黄的芦苇还在风中摇曳,厚厚的落叶依然密密地覆盖着大地.树上没有叶子,自然不见红枫,这是此次来加拿大的遗憾,但当我们拉长了景深后,却见到了另一番景致:层林中,枯木残枝横七竖八;溪河边,低缓的岸上,树枝枯草斜挂在水中,除了一些野禽,看不到一丝人的踪迹;透过丛林隐约可见的农家小舍,似乎也是与那片树林一起生长的.在城里,房子和道路以外的所有土地上,几乎全部都是树和草,私家庭园的绿化也大多不力修饰.崇尚自然是加拿大人生活的一部分.     

Dynamic fracture toughness of X70 pipeline steel and its relationship with arrest toughness and CVN

The dynamic fracture toughness K_1d and J_1d, arrest toughness K_1a and Charpy V-notched impact toughness (CVN) of a pipeline steel, X70, were studied at different temperatures. It was found that fracture toughness was strongly affected by temperature and loading rate. The fracture toughness decreases with decreasing temperature from 213 to193 K and increasing loading rate from to . At constant temperatures, only increasing loading rate can induce the transition from ductile to brittle. There exists a fracture transition caused by loading rate. Through thermal activation analysis, a quantitative relationship has been derived:

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. It can describe the fracture process at different temperatures and loading rates. At a loading rate of , the relationship can predict arrest toughness well. It provides the possibility of measuring arrest toughness with small size specimen. An empirical equation has been derived: CVN=4.84×10⁶T^−2.8K_1d(K_1a), which correlates K_1d and K_1a with CVN in one equation. This means that we can calculate K_1d and K_1a when we get CVN.