Kinetic Evaluations for the Sorption Process of Lanthanide Ions with Poly-<Emphasis Type="Italic">O</Emphasis>-toluidine Zr(IV) Tungstophosphate

The kinetic models for sorption of La³⁺, Ce³⁺ and Nd³⁺ ions on poly-o-toluidine Zr(IV) tungstophosphate (POTZr(IV)WP) were investigated under effecting of contact time, initial concentration and temperature. A comparison of kinetic models applied to the adsorption rate data of La³⁺, Ce³⁺ and Nd³⁺ ions on POTZr(IV)WP was evaluated for the pseudo-first order, the pseudo-second order, homogeneous particle diffusion and intra-particle diffusion kinetic models. The results showed that both the pseudo second-order and the homogeneous particle diffusion models were found to best correlate the experimental rate data. The particle diffusion coefficients (D_i) and energy of activation (E_a) have been estimated. These investigations revealed that the equilibrium is attained faster at higher temperatures.     

In vivo study of hybrid biomaterial scaffold bioactive glass–chitosan after incorporation of Ciprofloxacin

The present study aimed to evaluate the effect of bioactive glass as well as the presence of Ciprofloxacin drug (%Cip) into bioactive glass–chitosan composite on the in vivo behavior of these scaffolds. These scaffolds were implanted in the femoral condyl of an ovariectomized rat. The serum and organs (liver and kidney) of the under investigated rats were analyzed. Also the physicochemical properties of the prepared implants were assessed using Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) before and after implantation (at different periods of implantation). Biochemical and histological analyses of the under investigated rats proved the biocompatibility of the prepared scaffolds. The hydroxyapatite like layer was significantly precipitated on the surface of BG–CH scaffold than BG–CH–20Cip. In this same period, FT-IR of BG–CH shows complete disappearance of Si–O–Si. Their characteristics bands were replaced by P–O group arisen form bone apatite bands. Physicochemical results show progressive degradation of BG–CH and BG–CH–20Cip that occurred at the same time as replacement of the implant by an apatite layer. However, the bioresorbability and bioactivity of BG–CH are faster than those of BG–CH–20Cip. Therefore, the incorporation of the Ciprofloxacin in the BG–CH induces a retarding effect on the formation of the hydroxyapatite, and consequently on the ossification, without any side effects on the liver–kidney.     

SiC_p/Cu梯度复合材料热疲劳性能研究

采用粉末冶金方法制备了4种SiC颗粒呈渐变分布的梯度复合材料,应用扫描电子显微镜、X射线衍射仪、自动显微硬度计等,研究了梯度复合材料的显微组织、硬度分布和热疲劳性能。结果表明,SiCp/Cu梯度复合材料基体连续,梯度层过渡均匀,显微组织及硬度呈梯度分布;梯度复合材料的SiC颗粒渐变过渡越均匀,梯度复合材料抗热疲劳性能越好。     

UV resonance Raman probe of heme-bound imidazole established by 15N-labeling of hemoglobin

Recent studies of Cu, Zn superoxide dismutase, and of zinc-finger peptides have established that histidine ligands can be detected in ultraviolet resonance Raman (UVRR) spectra, following NH/D exchange of the imidazole. UVRR spectroscopy therefore offers promise for monitoring histidine ligation in heme proteins. In this work, we characterize heme-bound histidine UVRR bands for N-acetyl-microperoxidase-8 (MP-8) and microperoxidase-11 (MP-11), and also for hemoglobin (Hb). The Hb UVRR spectra are dominated by tyrosine and tryptophan contributions, but a band appears at 1340 cm⁻¹ in D₂O solution, which is assigned to a mode of Fe-bound imidazole. This band shifted 24 cm⁻¹ in protein which was labeled with ¹⁵N via expression of the Hb gene in E. coli grown on ¹⁵NH₄⁺. In MP-11, the position of this band is insensitive to ligation or oxidation state changes, but it is 2 cm⁻¹ lower in deoxyHb than in the CO adduct. This shift may reflect mechanical forces on the proximal histidine in the T state, and/or changes in its H-bonding.     

Preparation of ion-exchange celluloses. I. Anion exchange celluloses

Cellulose–poly(glycidyl methacrylate) graft copolymer (CPGMA) was treated with ammonia (AH), ethylamine (EA), diethylamine (DEA), and triethylamine (TEA). Factors affecting the reaction, such as reaction duration, temperature, liquor ratio, pH, and aminating agent/epoxide molar ratio were studied. A mechanism of the reaction was suggested. The anion exchange celluloses were characterized by studying its capacity, potentiometric titration, and durability to use. Potentiometric titration of the produced anion exchangers has been studied and pK_b values were found to be 6.1, 7.6, and 8.9 for DEA–CPGMA, EA–CPGMA, and AH–CPGMA, respectively.     

Redox shuttles for safer lithium-ion batteries

Overcharge protection is not only critical for preventing the thermal runaway of lithium-ion batteries during operation, but also important for automatic capacity balancing during battery manufacturing and repair. A redox shuttle is an electrolyte additive that can be used as intrinsic overcharge protection mechanism to enhance the safety characteristics of lithium-ion batteries. The advances on stable redox shuttles are briefly reviewed. Fundamental studies for designing stable redox shuttles are also discussed.     

Polymerization kinetics of indene, methyl methacrylate and acrylonitrile and characterization of their terpolymer

The free radical terpolymerization of indene (In), methyl methacrylate (MMA) and acrylonitrile (AN) has been investigated. The rate of polymerization of all the binary systems involved has been measured dilatometrically for the homogeneous polymerization. The reactivity ratios of the three binary systems were calculated and were found to be equal to 0.031 and 0.397 for In/AN copolymers and 0.02 and 3.82 for In/MMA copolymers and finally 0.152 and 1.20 for AN/MMA copolymers. The rate of terpolymerization in bulk has been measured as well as the relationship between the monomer mixture composition and the obtained terpolymer in order to construct the compositional triangle. Also the effect of initiator concentration on the rate of terpolymerization was investigated. The activation energy of terpolymerization was determined. The terpolymers were characterized by spectral and thermo-gravimetric analyses. The data indicates that polyindene improves the thermal stability of the prepared terpolymers.     

New optically active poly(amide-imide)s based on N,N′-(pyromellitoyl)-bis-L-amino acid and 1,3-bis(4-aminophenoxy) propane: Synthesis and characterization

Five new poly(amide-imide)s 8a–e were synthesized through the direct polycondensation reaction of five chiral N,N′-(pyromellitoyl)-bis-L -amino acids 3a–e with 1,3-bis(4-aminophenoxy) propane 7 in a medium consisting of N-methyl-2-pyrrolidone, triphenyl phosfite, calcium chloride, and pyridine. The polycondensation reaction produced a series of novel poly(amide-imide)s containing trimethylene moiety in the main chain in high yield with inherent viscosities between 0.34 and 0.65 dL/g. The resulted polymers were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity, and solubility tests. Thermal properties of these polymers were investigated by using thermal gravimetric analysis (TGA) and differential thermal gravimetric (DTG). All of the polymers were soluble at room temperature in polar solvents such as N,N-dimethyl acetamide, N,N-dimethyl formamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone. N,N′-(pyromellitoyl)-bis-L -amino acids 3a–e were prepared in quantitative yields by the condensation reaction of pyromellitic dianhydride (1,2,4,5-benzenetetracarboxylic acid 1,2,4,5-dianhydide) 1 with L -alanine 2a , L -valine 2b , L -leucine 2c , L -isoleucine 2d , and L -phenyl alanine 2e in acetic acid. Also 1,3-bis(4-aminophenoxy) propane 7 was synthesized by using a two-step reaction. At first 1,3-bis(4-nitrophenoxy) propane 6 was prepared from the reaction of 4-nitrophenol 4 with 1,3-dibromoprapane 5 in NaOH solution. Then, dinitro compound 6 was reduced by using Na₂S. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

搅拌摩擦加工制备具有单一和混合表面的Al5083/CeO_2/SiC复合材料的显微组织和磨损行为（英文）

利用搅拌摩擦加工(FSP),将纳米尺寸的氧化铈(CeO_2)和碳化硅(SiC)颗粒以单独和混合形式嵌入Al5083合金基体,制备表面复合材料,并研究这些增强相对合成的表面复合层显微组织和耐磨性能的作用。在室温下用销-盘式磨损试验机检测合成的单独和混合表面复合层的磨损特性。用光学显微镜和扫描电镜观察FSPed区和磨损表面的显微组织。在熔核区可观察到显著的晶粒细化和均匀分布的增强颗粒。与基体金属相比,所有复合材料都具有更高的硬度和更好的耐磨性。其中,混合复合材料Al5083/CeO_2/SiC的耐磨性能最好,摩擦因数最低,而Al5083/SiC的硬度最高,是Al5083基体合金硬度的1.5倍。混合复合材料表面耐磨性能的提高是由于CeO_2颗粒的固体润滑效果。非复合材料中主要的磨损机制是严重的粘着磨损,当存在增强颗粒时转变为磨粒磨损和分层。     

BaSO4‐, CaF2‐, and Al‐Maleate‐Derived Nanocomposite Coatings with Excellent Mechanical,Thermal, and Optical Properties

Acrylate‐based nanocomposite coatings prepared from uniformly sized, nanoscaled inorganic, i.e., BaSO₄‐ and CaF₂‐ as well as organometallic, i.e., Al‐maleate‐derived nanoparticles were prepared applying photochemical curing. Excellent mechanical and thermal stability as well as high optical transparency was achieved as compared to standard SiO₂‐based coatings. The performance of CaF₂‐based nanocomposites could be further enhanced by addition of nanocorundum. A comprehensive data set on surface and Martens hardness, the penetration depths, glass transition temperatures, and UV–Vis transparency of the final coatings is presented.