Variations in Cytotoxicity During Ozonation of Substituted Aromatics

The cytotoxicity test, using BGM cells and a colorimetric protein assay (Lowry, 1951) was a more sensitive modification of those described by Christian (1973) and Elias, et al. (1978). The cytotoxicity varied during ozonation, reaching a maximum after 50%90% degradation of the initial compound; aniline solution, 6.5x10³ M, showed a maximum cytotoxicity at 90% degradation after 60 min of ozonation, which decreased to 0% after 180 min 0₃. Ozonated nitro– and chloro–cresol solutions showed similar patterns. The variations in cytotoxicity seem to be related to the formation of intermediate oxidation products. The preliminary results suggest that this type of test, being both simple and fast, would be useful in toxicological screening of wastewater.     

乙酰化淀粉/PBS制备生物降解塑料的研究

以玉米淀粉为原料,以醋酸酐为乙酰化试剂,氢氧化钠为催化剂,利用微波辐射技术制得乙酰化淀粉。用制备的乙酰化淀粉与聚丁二酸丁二醇酯(PBS)共混,制备了可生物降解热塑性淀粉塑料。研究了共混物制备的最佳工艺条件及其力学性能、生物降解性能及吸水性能,并对产物进行了红外光谱结构分析和表面电镜扫描分析。     

绿色阻垢剂的进展

随着人类环保意识的增强,绿色阻垢剂因其不但具有高的阻垢性能,而且具有良好的生物降解性和无毒性等优点,因此成为阻垢剂的研究热点。本文阐述了绿色阻垢剂尤其聚天冬氨酸（PASP）和聚环氧琥珀酸（PESA）的研制情况,并展望了阻垢剂的发展方向。     

生物可降解山麻杆韧皮纤维增强PBS复合材料的性能研究

以山麻杆韧皮纤维为增强体,其与PBS颗粒按质量比20∶80模压成型制备了4种板材,探讨了表面处理对纤维微观结构与物理性能的影响,分析比较了板材力学性能及生物降解性。结果表明, 采用物理化学相结合方法预处理后,表面依然存留一定量的果胶等物质;预处理纤维进一步碱处理后表面出现“S”形凹槽,预处理纤维进一步偶联剂处理后表面凹槽连续性好、深度深;碱处理、偶联剂处理后纤维拉伸强度分别提高5.08 %和降低3.58 %;相比纯PBS,偶联剂处理后纤维复合材料拉伸强度与弯曲强度各提高48.32 %和25.97 %,拉伸模量与弯曲模量各提高146.45 %和128.30 %;3种纤维复合材料生物可降解性变化趋势一致,但偶联剂处理后的材料失重率变化幅度最小。     

Effect of different CaSO4 contents on CaSiO3-CaSO4 porous composite bone scaffolds by 3D gel-printing

Porous CaSiO₃-CaSO₄ composite scaffolds were successfully prepared by 3D gel-printing (3DGP) technology in this study. In order to further improve the degradation performance of pure CaSiO₃ scaffolds, the effect of different CaSO₄ doping contents on CaSiO₃-CaSO₄ composite scaffolds was studied. The results show that when the porous composite scaffolds were placed in simulated body fluid (SBF) for 5 weeks, the weight loss rate was 2.41% (CaSiO₃-1%CaSO₄), 3.97% (CaSiO₃-3%CaSO₄), 4.18% (CaSiO₃-5%CaSO₄), 6.87% (CaSiO₃-7%CaSO₄), and 12.93% (CaSiO₃-9%CaSO₄), respectively, which could be concluded that CaSO₄ doping has a significant effect on improving the biodegradability of CaSiO₃ scaffolds. And CaSO₄ doping can also effectively improve the compressive strength of composite scaffolds and that of CaSiO₃-3%CaSO₄ composite scaffolds was tested as 54.67 MPa, and the shrinkage rate of porous composite scaffolds was nearly 11.4%, which meets the application requirements of bone repairing engineering.     

高透明羧甲基纤维素/纤维素纤维复合薄膜的制备及其力学性能

针对传统电子器件衬底柔韧性差、不可生物降解的问题,研究了以羧甲基纤维素（CMC）和纤维素纤维为原料,结合抄纸和浸渍工艺,制备在柔性电子器件领域具有潜在应用的高透明CMC/纤维素纤维复合薄膜衬底。分别探究了CMC与北木纤维的配比和CMC分子量对薄膜透明度和力学性能的影响。研究了纤维素纤维的种类（北木、桉木、马尼拉麻和蔗渣纤维）对高透明CMC/纤维素纤维复合薄膜力学性能的影响。结果表明：CMC与北木纤维质量比为7∶3、CMC分子量为700 000时,所制备CMC/北木纤维复合薄膜的透明度为90%,拉伸强度约为111 MPa,耐折度达到2 526次。这种可生物降解、高柔韧性、高强度和高透明的CMC/纤维素纤维复合薄膜有望作为衬底用于构建下一代绿色、柔性电子器件,促进人类社会的可持续发展。     

硼硅酸盐生物玻璃的制备及其体外生物活性和降解性

采用熔融法制备了NaO-CaO-SiO2-P2O5-B2O3玻璃,用质量损失分析、pH值测定和X射线衍射、电子显微镜以及电感耦合等离子体离子浓度分析法表征玻璃与稀K2HPO4溶液的类生物反应,研究了这类玻璃的生物活性和生物降解性.结果表明:当玻璃中B2O3/SiO2的摩尔比为3:1时,生物活性较好.随着B2O3与SiO2的摩尔比减小,玻璃的降解速度变慢,获得的羟基磷灰石结晶度较低.利用此特性可控制生物玻璃的降解速度,从而与骨细胞生长速度相匹配.因此,此类硼硅酸盐生物活性玻璃有望在硬组织工程支架材料中得到应用.     

Synthesis and biodegradability evaluation of 2‐methylene‐1,3‐dioxepane and styrene copolymers

Biodegradable copolymers of 2‐methylene‐1,3‐dioxepane (MDO) and styrene (ST) were synthesized by free‐radical copolymerization using di‐t‐butyl peroxide (DTBP) as the initiator. The copolymers containing ester units were characterized by Fourier transform infrared (FTIR), ¹H‐NMR, and ¹³C‐NMR spectroscopy. Their molecular weight and polydispersity index were determined by gel permeation chromatography (GPC). In vitro enzymatic degradation of poly(MDO‐co‐ST) was performed at 37°C in phosphate buffer solution (PBS, pH = 7.4) in the presence of Pseudomonas lipase or crude enzyme extracted from earthworm. The experiment showed that incorporating ester units into C? C backbone chain of polystyrene would result in a biodegradable copolymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1146–1151, 2007     

Novel glucose-derived gemini surfactants with a 1,1′-ethylenebisurea spacer: Preparation, thermotropic behavior, and biological properties

In the search for environmentally safe surfactants made from inexpensive and renewable sources, the interest has mainly been focused on new saccharide derivatives. This report describes the synthesis of newly designed nonionic gemini compounds comprising two reduced sugar headgroups, two alkyl tails, and a 1,1′-ethylenebisurea entity as the spacer linking two amphiphilic glucose-derived moieties. Thus, the series of N,N′-bis[(3-alkyl-3-deoxy-d-glucitol)ureido]ethylenediamines (bis(C_nGT), with C_n=n-C₉H₉, n-C₆-H₁₃, n-C₈H₁₇, n-C₁₀H₂₁, or n-C₁₂H₂₅), were prepared using a convenient procedure starting from easily accessible reagents such as d-glucose, n-alkylamines, urea, and ethylenediamine. Their structure and purity were confirmed by means of elemental analysis, electrospray ionization mass spectrometry, and ¹H and ¹³C nuclear magnetic resonance spectroscopy. Additionally, the present contribution introduces selected properties of these surfactants, including their thermotropic behavior and biological properties. The presence of two phase transition points, determined using the differential scanning calorimetry method, indicates liquid-crystalline mesophase formation upon heating. Furthermore, using the closed-bottle test (OECD Guideline 301D) as well as the biological oxygen demand test for insoluble substances for biodegradability measurements, it has been concluded that the tested glucose-derived gemini structures achieve more than 60% biodegradation after 64–75 test days. All tested surfactants were practically nontoxic to bacteria, yeast, and molds. Owing to their fitting aggregation ability as well as their nontoxicity, they constitute an interesting group of surfactants for various applications.