Flexible Phase Change Material Fiber: A Simple Route to Thermal Energy Control Textiles

A flexible hollow polypropylene (PP) fiber was filled with the phase change material (PCM) polyethylene glycol 1000 (PEG1000), using a micro-fluidic filling technology. The fiber’s latent heat storage and release, thermal reversibility, mechanical properties, and phase change behavior as a function of fiber drawing, were characterized. Differential scanning calorimetry (DSC) results showed that both enthalpies of melting and solidification of the PCM encased within the PP fiber were scarcely influenced by the constraint, compared to unconfined PEG1000. The maximum filling ratio of PEG1000 within the tubular PP filament was ~83 wt.%, and the encapsulation efficiencies and heat loss percentages were 96.7% and 7.65% for as-spun fibers and 93.7% and 1.53% for post-drawn fibers, respectively. Weak adherence of PEG on the inner surface of the PP fibers favored bubble formation and aggregating at the core–sheath interface, which led to different crystallization behavior of PEG1000 at the interface and in the PCM matrix. The thermal stability of PEG was unaffected by the PP encasing; only the decomposition temperature, corresponding to 50% weight loss of PEG1000 inside the PP fiber, was a little higher compared to that of pure PEG1000. Cycling heating and cooling tests proved the reversibility of latent heat release and storage properties, and the reliability of the PCM fiber.     

番泻叶、聚乙二醇和二甲基硅油联合应用对胶囊内镜检查可见度及检出率的影响

目的探讨番泻叶、聚乙二醇和二甲基硅油联合应用对于胶囊内镜(CE)检查可见度及检出率的影响。方法选取该院2016年6月-2018年9月拟行CE检查的患者126例,采用随机数表法分为对照组(n=62)与观察组(n=64),两组检查前禁食3 d,对照组予以聚乙二醇和二甲基硅油作为肠道准备,观察组在此基础上给予口服番泻叶。比较两组胃排空时间、小肠转运时间、胃和小肠的染色节段长度、绿色条带长度、肠道清洁程度、两组病变检出情况及不良反应发生情况。结果两组患者胃排空时间、小肠转运时间、胃和小肠的染色节段无明显差异(P0.05);观察组全小肠和远端小肠绿色条带长度短于对照组,差异均有统计学意义[(5.53±2.93) vs (6.74±2.76)cm;t=2.39,P=0.019;(3.37±2.04) vs (5.56±2.13)cm;t=5.90,P=0.000];两组近端小肠清洁程度差异无统计学意义(P0.05),观察组远端小肠(89.06%vs59.68%,χ2=14.35,P=0.000)和全小肠(87.50%vs 48.39%,χ2=22.23,P=0.000)清洁率明显高于对照组,差异有统计学意义;观察组病变总检出率明显高于对照组(92.18%vs 72.58%,χ2=8.40,P=0.004);两组不良反应发生率差异无统计学意义(17.74%vs 18.75%,P0.05)。结论添加番泻叶可有效提高聚乙二醇和二甲基硅油对于CE的检查可见度和检出率。     

La cristallurie dans l’intoxication à l’éthylène glycol

When seen, some habits of calcium oxalate monohydrate crystals (whewellite) are so typical of ethylene glycol intoxication that they may be helpful for its diagnosis when circumstances are not clearly established.     

Polyethylene glycol as an alternative polymer solvent for nanoparticle preparation

Solvent toxicity is one of the major drawbacks in the preparation of polymeric nanoparticles today. Here, polyethylene glycols (PEGs) are proposed as non-toxic solvents for the preparation of polymeric nanoparticles. Based on a preparation process similar to the solvent displacement technique, several process parameters were examined for their effects on the properties of the prepared nanoparticles by this method to achieve the optimum preparation conditions. The investigated parameters included polymer type and concentration, volume and temperature of the dispersing phase, methods of dispersing the solvent phase into the non-solvent phase, duration and speed of stirring and washing by dialysis. Ammonio methacrylate copolymer (Eudragit RL), poly-lactide-co-glycolide (PLGA), and PEG-PLGA were found to be successful polymer candidates for the preparation of nanoparticles by this method. Nanoparticles with diameters ranging from 80 to 400 nm can be obtained. The encapsulation efficiencies of bovine serum albumin, and lysozyme as model proteins were ranging from 7.3 ± 2.2% to 69.3 ± 1.8% depending on the strength of polymer–protein interaction. Biological assays confirmed a full lysozyme activity after the preparation process. PEG proved to be a suitable non-toxic solvent for the preparation of polymeric protein-loaded nanoparticles, maintaining the integrity of protein.     

The effect of polymer molecular weight and cell seeding density on viability of cells entrapped within PEGDA hydrogel microspheres

Abstract

Cell microencapsulation can be used in tissue engineering as a scaffold or physical barrier that provides immunoisolation for donor cells. When used as a barrier, microencapsulation shields donor cells from the host immune system when implanted for cell therapies. Maximizing therapeutic product delivery per volume of microencapsulated cells necessitates first optimising the viability of entrapped cells. Although cell microencapsulation within alginate is well described, best practices for cell microencapsulation within polyethylene glycol is still being elucidated. In this study we microencapsulate mouse preosteoblast cells within polyethylene glycol diacrylate (PEGDA) hydrogel microspheres of varying molecular weight or seeding densities to assess cell viability in relation to cell density and polymer molecular weight. Diffusion studies revealed molecule size permissible by each molecular weight PEGDA towards correlating viability with polymer mesh size. Results demonstrated higher cell viability in higher molecular weight PEGDA microspheres and when cells were seeded at higher cell densities.     

Bilateral cochlear implantation after ethylene glycol intoxication: a case report

Abstract

Objective

To report a case of deafness and blindness caused by ethylene glycol poisoning and treated by bilateral simultaneous cochlear implantation.

Study design

Case report.

Setting

University teaching hospital, tertiary referral center.

Patient

37 years old man poisoned with ethylene glycol.

Intervention

Bilateral simultaneous Medel Sonata cochlear implants.

Outcome measure

BKB sentences (Bamford–Kowal–Bench sentence tests); AB words (Arthur Boothroyd monosyllabic words).

Results

Successful rehabilitation of hearing in a case of deafness and blindness of acute onset.

Conclusion

Bilateral CI is an effective method of hearing rehabilitation in presence of additional disability (blindness).     

Universal Bioinert Control of Polystyrene Interfaces via Hydrophobic‐Driven Self‐Assembled Surface PEGylation with a Well‐Defined Block Sequence

This work proposes a new molecular insight of interfacial design in the control of antifouling performance for the versatile biofoulants, including proteins, blood cells, tissue cells, and bacteria. A self‐assembled bioinert interface with universal fouling resistance to general biofoulants via hydrophobic‐driven surface PEGylation is presented. The study systematically discriminates the optimum PEGylated block polymer configuration and hydrophobic/hydrophilic segmental ratio enabling to optimize the surface coverage by the bioinert moieties, thus ensuring the best resistance to biofouling. For similar copolymer molecular weights and similar polystyrene (PS)/poly(ethylene glycol) methacrylate (PEGMA), the coating density obtainable is the highest if a random copolymer is used, while it is the lowest with a triblock copolymer. That measured with a diblock copolymer lies in between. Random copolymers offer more numerous anchoring possibilities than diblock copolymers, while they are importantly fewer if triblock copolymers are used. For similar total number of hydrophilic blocks, the diblock copolymer is more efficient to resist larger cells (leukocytes, fibroblasts) while the triblock is better to promote mitigate biofouling by smaller molecules or cells (proteins, platelets, red blood cells). The length of the hydrophilic PEGylated block seems to dominate fouling resistance of large biofoulants.     

Study of Silica‐Supported Chromocene Catalysts for Ethylene Polymerization

Ultrahigh molecular weight polyethylene (UHMWPE) has drawn great interest from researchers because it possesses many excellent properties such as superb strength and impact resistance, which other polyolefin cannot achieve. A silica‐supported chromocene catalyst, for the production of UHMWPE, is successfully developed. The polyethylene (PE) produced by the chromocene catalyst can achieve a molecular weight (MW) of over 3 × 10⁶ g mol^?1 with narrow molecular weight distribution (MWD) a value of approximately three. The activity calculated by Cr per unit reaches the maximum when the loading of Cr is 1.7 wt%. With the increasing loading of chromocene, the MW shows a small increase and the MWD becomes narrower. The chromocene catalyst for ethylene polymerization also shows a significant hydrogen response. With 0.01 MPa hydrogen added into the ethylene polymerization, the MW of the PE decreases immensely to only 0.7 × 10⁶ g mol^?1 and the MWD is broadened from <3 to ≈12. If the amount of hydrogen increases, the MW continues to decrease and the MWD becomes wider. The MW of the PE produced by the chromocene catalyst can be regulated easily by adjusting the amount of hydrogen.     

经乙二醇诱导的改良型草酸钙肾结石果蝇模型

目的:通过一种改良方法构建果蝇草酸钙肾结石模型。方法:配制标准培养基和造模用培养基，空白对照组果蝇仅予标准培养基，而传统模型组和改良模型组分别从成虫期和幼虫期开始摄入含 0.5%乙二醇( EG)的造模用培养基。于偏光显微镜下观察并评估各组果蝇马氏管内成石情况，分别记录模型组成石率达 100%所花时间，并对成石率 100%时模型组间“ ++”和“ +++”所占比率进行比较；用傅立叶变换拉曼光谱仪鉴定模型组果蝇马氏管内结石成分。绘制各组果蝇生存曲线，并比较生存周期差异。结果:改良模型组和传统模型组分别在果蝇成虫日龄 14 d和 22 d，马氏管内成石率达到 100%。当改良模型组和传统模型组成石率均达到 100%时，两组“ ++”与“+++”所占比率分别为(40.5±4.4)%和(39.0±4.2)%，差异无统计学意义(P＞ 0.05)；拉曼位移的主峰主要集中在 1 462 cm-1、1 463 cm-1和 1 473 cm-1，说明模型组果蝇马氏管内结石成分均为草酸钙。空白对照组、传统模型组和改良模型组的最高寿命分别为 76 d、70 d和 68 d，中位生存时间分别为 35 d、30.5 d和 30 d，与空白对照组相比，模型组生存周期均显著缩短(P均＜ 0.01)，但传统模型组与改良模型组间差异无统计学意义( P＞ 0.05)。结论:改良型造模方法使果蝇在其幼虫期即摄入 0.5% EG，缩短了模型构建周期且具有可重复性，值得进一步研究推广。