Ethylenediamine tetraacetic acid modification of crosslinked chitosan designed for a novel metal‐ion adsorbent

Novel chitosan‐based adsorbent materials were synthesized with a higher fatty diacid diglycidyl as a crosslinking agent, and the adsorption ability of the resulting polymers for several metal ions was evaluated. Selective adsorption for Cu²⁺ in comparison with other divalent metal ions, such as Ni²⁺, Pb²⁺, Cd²⁺, and Ca²⁺, was observed with the crosslinked chitosan sorbent at pH 6; however, the adsorption power decreased abruptly as the pH value of the solution decreased. The addition of ethylenediamine tetraacetic acid (EDTA) residues to crosslinked chitosan significantly enhanced the adsorption power for metal ions, especially for Ca²⁺. The adsorptivity of Ca²⁺ was dramatically improved with the introduction of EDTA residues, and the value was greater than that obtained with a commercial chelate resin (CR11). Although the adsorption power of the EDTA‐derivatized sorbent for other metal ions was just comparable to that of the CR11 material, the newly synthesized adsorbent could be used for the recovery of metal ions from industrial waste solutions with a relatively wide range of pHs, from 4.0 to 6.0. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2758–2764, 2004     

Phase Separation and Crystallization of BiSrCaCu2Al0.5Ox Glass

Al₂O₃ addition to the melt of a BiSrCaCu₂O _x composition was found by TEM observation to cause the liquid-liquid phase separation of the melt-quenched glass, and to result in preferential precipitation of superconducting Bi₂Sr₂Ca₁Cu₂O _x crystals from the melt during the cooling process.     

Intake of conjugated eicosapentaenoic acid suppresses lipid accumulation in liver and epididymal adipose tissue in rats

It has been reported that consumption of CLA and EPA alters lipid metabolism. CLA contains conjugated double bonds, and EPA is an n−3 PUFA. Based on the possibility that a molecule with both of these structures might have interesting physiological effects, we prepared conjugated FA from EPA by alkaline isomerization and examined the effects of the conjugated EPA (CEPA) on lipid metabolism in rats. Rats were fed by oral gavage every day for 4 wk with 200 mg of FA including linoleic acid, EPA, CLA, or CEPA. Compared with other groups, rats fed CEPA showed a significant weight loss in epididymal adipose tissue and significant decreases in the levels of liver TAG and total cholesterol (TC), indicating reduced accumulation of lipid in the liver and adipose tissue. The plasma levels of TAG, TC, FFA, and tumor necrosis factor-α in rats fed CEPA were reduced, as was the activity of the FA synthesis system in the liver, whereas the FA-β-oxidation system was activated by CEPA. These results suggest that intake of CEPA suppresses lipid accumulation in the liver and epididymal adipose tissue while increasing lipid catabolism in rats.     

The simulation of hydrolytic polymerization of ϵ-caprolactam in various reactors

The concrete simulation models dealing with the kinetic behavior of the hydrolytic polymerization of ?-caprolactam (CL) in various polymerization reactors used in the industry were described, and the method for their numerical solutions was presented. The characteristic data of the polymerization such as the concentrations of CL, end group, water, ?-aminocaproic acid, cyclic dimer, and the hot-water-soluble component, conversion, number average, and weight average molecular weights, and solution and melt viscosities can be calculated at every stage of the polymerization reaction, at every part of the reactors, and/or at the outlet of the reactors. The calculated values based upon the models were found to be quite compatible with the observed values for the reactors. The applicability of the technique was well confirmed for the quality control, process control, modification of existing plants, and development of new chemical process plants.     

Nanocomposites based on poly(ϵ‐caprolactone) and the montmorillonite treated with dibutylamine‐terminated ϵ‐caprolactone oligomer

Dibutylamine‐terminated ε‐caprolactone oligomers (CLOs: CLOL, CLOM, and CLOH) with number–averaged molecular weight (M_n), 500, 1300, and 2200, respectively, were synthesized by the ring‐opening polymerization of ε‐caprolactone initiated by 2‐(dibutylamino)ethanol in the presence of tin(II) 2‐ethylhexanoate. Nanocomposites based on poly(ε‐caploractone) (PCL) and the caprolactone oligomer‐treated montmorillonites (CLO‐Ms: CLOL‐M, CLOM‐M, and CLOH‐M) were prepared by melt intercalation method. The XRD and TEM analyses of the PCL composites revealed that the extent of exfoliation of the clay platelets increased with increasing molecular weight of the used CLOs. Tensile strength and modulus of the PCL/CLO‐M composites increased with increasing molecular weight of the CLO and increasing inorganic content. The tensile modulus of the PCL/CLOH‐M nanocomposite with inorganic content 5.0 wt % was three times higher than that of control PCL. Among the PCL/CLO‐M composites, the PCL/CLOM‐M composite had the highest crystallization temperature and melting temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of dietary lard containing higher alpha-linolenic acid on plasma triacylglycerol in rats

It is well known that the consumption of n-3 polyunsaturated fatty acid (PUFA) decreases the plasma triacylglycerol (TAG) level. The technology of elevating the content of n-3 PUFAs in pig meat has already reached a practical level. In this study, the effects of dietary lard containing higher alpha-linolenic acid (LNA) on plasma TAG were compared with those of normal lard in rats. The rats were fed a diet containing either 10% normal lard or a high linolenic lard for 4 weeks. The plasma and liver TAG levels in the high linolenic lard group were significantly lower than those in the normal lard group. The activity of the fatty acid synthase (FAS) of the liver in the high linolenic lard group was significantly lower than that in the normal lard group. The contents of n-3 PUFAs in hepatic total lipid, TAG fraction, and the phospholipids (PLs) fraction increased in the high linolenic lard group. The results indicate that the high linolenic lard suppressed hepatic FAS activity compared with the control lard, resulting in a lower concentration of plasma TAG. These results also suggest that pig meat containing high LNA may be more nourishing than normal pig meat.     

Distribution of antimicrobial resistant Salmonella in an urban river that flows through the provincial city of Miyazaki,Japan

There is limited information regarding antimicrobial resistant Salmonella in the aquatic environment. In this study, we investigated the distribution of antimicrobial resistant Salmonella in the Yae River at sites upstream, midstream and downstream of the urban area of Miyazaki City, Japan. Pulsed field gel electrophoresis was performed to evaluate the genetic relationship among antimicrobial resistant Salmonella. The percentage of isolates that were resistant to at least one antimicrobial agent in upstream, midstream, and downstream sites was 23% (resistant isolates/total isolates = 11/44), 3% (1/34) and 32% (12/38), respectively. The 11 isolates of multidrug‐resistant Salmonella collected from downstream were classified to have a common genetic pattern belonging to the same cluster with a 100% similarity level. The multidrug‐resistant Salmonella were obtained from an identical source and were present in an urban river near human habitation.     

超声冲击纳米化的研究现状与进展

首先介绍了超声冲击金属表面致纳米化的原理、强塑性变形诱导形成纳米晶的机理及纳米晶尺寸和晶粒取向的分析手段,然后结合表面静压力、振幅、单位面积冲击次数等参数变化,总结了超声冲击对金属硬度、粗糙度、残余应力及疲劳性能的影响。超声冲击后,材料表面硬度会大幅提升,表面形貌规则且平整度得到改善。超声冲击诱导产生的纳米晶和残余压应力对提高材料疲劳强度有积极作用。统计认为,超声冲击表面强化对弯曲疲劳试件疲劳性能的提升更大,且试件107周次以上的疲劳极限在(0.50~0.65)σb内。对于处理后产生相变的材料,硬度和强度更高的相甚至能将表层硬度和疲劳极限提高到2倍。最后,综合阐述了超声冲击表面强化与等离子氮化、TiN生物覆膜、常规喷丸及激光喷丸等复合处理方式对材料性能的影响,并提出了基于超声冲击纳米化进行混合表面处理需注意的事项：工艺参数和处理顺序要恰当;考虑环境腐蚀时,要对纳米表面进行二次保护,从而提高材料的综合性能;纯机械方式复合处理要根据技术特点来筛选。     

Mechanism of gold-catalyzed carbon material growth

We demonstrate that nanosized Au particles have carbon solubility. Au-catalyzed carbon material growth by chemical vapor deposition undergoes a structural change, either a carbon nanowire or a single-walled carbon nanotube, depending on the catalyst particle size. This carbon material growth from Au is derived by the formation of Au-C eutectic nanosized alloy.     

Fe(III) containing MCM-48 type mesoporous molecular sieves with framework zeolite secondary building units

Fe(III) containing mesoporous materials (FeMMSH) with zeolite building units were first time synthesized. XRD and N2 adsorption/desorption analysis confirm the mesoporous characters similar to MCM-48. FT-IR analysis of FeMMSH showed an additional band at about 530-550 cm(-1), characteristic of double five-membered ring of zeolite (ZSM-5) secondary building unit. The Fe(III) in FeMMSH materials is present in tetrahedral, and distorted tetrahedral framework are evident from EPR and DRUV-VIS spectra.