Water absorption properties of phosphate glass fiber‐reinforced poly‐ϵ‐caprolactone composites for craniofacial bone repair

The moisture uptake of polymers and composites has increasing significance where these materials are specified for invasive, long‐term medical applications. Here we analyze mass gain and the ensuing degradation mechanisms in phosphate glass fiber reinforced poly‐?‐caprolactone laminates. Specimens were manufactured using in situ polymerization of ?‐caprolactone around a bed of phosphate glass fibers. The latter were sized with 3‐aminopropyltriethoxysilane to control the rate of modulus degradation. Fiber content was the main variable in the study, and it was found that the moisture diffusion coefficient increased significantly with increasing fiber volume fraction. Diffusion, plasticization, and leaching of constituents appear to be the dominant aspects of the process over these short‐term tests. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Numerical treatment of a quasilinear initial value problem with boundary layer

The paper deals with the singularly perturbed quasilinear initial value problem exhibiting initial layer. First the nature of solution of differential problem before presenting method for its numerical solution is discussed. The numerical solution of the problem is performed with the use of a finite-fitted difference scheme on an appropriate piecewise uniform mesh (Shishkin-type mesh). An error analysis shows that the method is first-order convergent except for a logarithmic factor, in the discrete maximum norm, independently of the perturbation parameter. Finally, numerical results supporting the theory are presented.     

Effect of Surface and Oxygen Coverage on Ethylene Epoxidation

Ethylene epoxidation was studied as a function of oxygen coverage; for three different surfaces (111), (100) and (110) of three different IB metals using periodical DFT calculations. Oxygen coverage dependence was tested for 11, 25 and 33?% surface oxygen on Ag(111) surface. Calculations showed that increasing oxygen amount increased the exothermicity of the reaction while lowering the activation barriers. At studied oxygen ratios ethylene oxide and acetaldehyde formations proceed through OMC intermediate. In agreement with earlier studies, predicted selectivity is independent of surface structure. Generally the activation barriers for aldehyde formation are lower than those for epoxide formation on the studied surfaces. On copper surfaces the high stability of the precursor intermediates caused high activation barriers for the product formations. Also, epoxide formation is endothermic with respect to pre-oxygenated copper surfaces. On the other hand gold surfaces showed the smallest activation barriers for the product formations. Ag surfaces did not show conclusive differences for the activation barriers for epoxide versus aldehyde formation, which is in agreement with the ~50?% EO selectivity of the un-promoted metallic silver.     

Hydrogen liberation from the dehydrocoupling of dimethylamine–borane at room temperature by using novel and highly monodispersed RuPtNi nanocatalysts decorated with graphene oxide

Addressed herein, we reported the fabrication of the graphene oxide (GO) supported monodispersed ruthenium–platinum–nickel (RuPtNi) nanomaterials (3.40 ± 0.32 nm) to be utilized as a catalyst in the process of dimethylamine borane (DMAB) dehydrogenation. The nanoparticles were fabricated through the ultrasonication method by co-reducing the Ru³⁺, Pt²⁺ and Ni²⁺ cations and then the nanomaterials were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), inductively coupled plasma optical emission spectrometry (ICP-OES), and X-ray photoelectron spectroscopy (XPS). The fabricated nanomaterials showed outstanding efficiency and remarkable reusability in addition to their record catalytic activity at low temperatures and with extreme low concentrations. They had a significantly high turnover frequency (TOF) (727 h^?1) and low activation energy (E_a) (49.43 ± 2 kJ mol^?1) for DMAB dehydrocoupling. To the best of our knowledge, RuPtNi@GO NPs become a very promising candidate as the best catalyst ever.     

Dyeing,fastness, and cytotoxic properties,and phenolic constituents of Anthemis tinctoria var. tinctoria (Asteraceae)

The present study focused on dyeing, fastness, cytotoxic properties, and phenolic constituents of various types of fabrics including viscose, cotton, wool, and polyester-viscose blended fabrics with different parts of Anthemis tinctoria var. tinctoria. Comparative study was carried out between ethanol and aqueous extracts of stem, flower, and root of the plant in terms of phenolic constituents, cytotoxic activity, and dyeing properties. It was found that the quantity of phenolic constituents of ethanol and aqueous extracts was quite different. All parts of the plant extract show 0% cytotoxicity except ethanol extract of the root. All the extracts exhibit better cytotoxic activity than the standard cancer drug 5-Florouracil. Ethanol and water extracts of A. tinctoria var. tinctoria plant were used to dye fabrics, but only the water extract displayed dyeing properties. Best color strength value (K/S = 9.19) was obtained with aqueous extract of the stem in the presence of alum mordant for cotton fabrics.     

Propylene Epoxidation: High-Throughput Screening of Supported Metal Catalysts Combinatorially Prepared by Rapid Sol–Gel Method

The gas phase oxidation of propylene using molecular oxygen was studied on a variety of supported metal catalysts. The most promising PO activity was obtained for Cu supported on high surface area SiO₂ and the multimetallic systems exhibit synergistic effects that increased the desired PO yield by several folds for Ag promoted with Cu on SiO₂ after screening a large number of catalysts by a high throughput testing technique.     

A novel method for color determination of edible oils in L*a*b* format

A simple method that uses visible spectrophotometer data and an artificial neural network (ANN) was developed to determine edible oil color based on the L*a*b* format. The 100 oil samples consisted of nine pure oils, a sesame oil blend and three heated oils. Binary, ternary and quaternary mixtures of these 13 oils in different ratios were prepared, and absorbance values of the samples were measured in the visible region (380–700 nm). The absorbance values at wavelengths of 416, 456, 483, 537, 611 and 672 nm were used to train, validate and test the network. Strong correlations between the instrumental L*a*b*ΔE and the estimated L*a*b*ΔE were found for the test samples, with correlation coefficients (R²) of 0.989, 0.984, 0.996 and 0.992 for L*, a*, b*, and ΔE, respectively. The effects of number and combination of the wavelengths used for training of the ANN on the estimation capability of the network for the test samples were also investigated. Although a good agreement, average R² of 0.991– 0 993 for L*a*b*, was obtained for combinations composed of three to six wavelengths with 483 and 537 nm in common, the best R² value was obtained when all six wavelengths were used to train the ANN. The developed method is objective, cost effective and simple, and allows the color measurement with a basic visible spectrophotometer and disposable cuvettes.     

New Catalytic Materials for the Direct Epoxidation of Propylene by Oxygen: Application of High-Throughput Pulsed Laser Ablation

New catalytic materials were prepared by depositing nanoparticles of 35 different metals as well as their select binary combinations on Al₂O₃, CeO₂, SiO₂, TiO_2, and ZrO₂ supports. Nanoparticles were synthesized by high-throughput pulsed laser ablation (PLA). Catalytic materials were then screened for their selectivities towards the synthesis propylene oxide (PO) from propylene and oxygen using array channel microreactors at 1 atm and 300, 333, and 367 °C. A gas hourly space velocity (GHSV) of 20,000 h^?1 was used at the feed gas composition of 20% O₂, 20% C₃H₆ and the balance He. Initial screening experiments resulted in the discovery of SiO₂ supported Cr, Mn, Cu, Ru, Pd, Ag, Sn, and Ir as the most promising leads for PO synthesis. Subsequent experiments pointed to bimetallic Cu-on-Mn/SiO₂, for which the PO yields increased several fold over single metal catalysts. For multimetallic materials, the sequence of deposition of the active metals was shown to have a significant effect on the resulting catalytic activity and selectivity.     

Development of arteriovenous anastomoses in Rattus norvegicus species during the fetal period

In this study carried out on the development of arteriovenous anastomoses (AVAs) in Rattus norvegicus species, the fetus was followed up 10 days after post coitum (pc). The sections obtained from the fetuses of 10-20-day rats were subjected to the usual processes for examination under the light microscope. Various staining processes were applied on the preparations and the simple and glomus types of AVAs determined in the mesenchyme of fetuses observed to birth every day. The regions with AVAs were then photographed by photomicroscopy and evaluated. From the 10-day embryo to birth, an increase in the smooth muscles in the wall structure of simple anastomoses was observed. It was however very difficult to follow up this increase in glomus anastomoses because the wall structure is more complicated. Their morphology was examined and compared with that in literature.     

Dyeing of Wool and Cotton with Extract of the Nettle (Urtica dioica L.) Leaves

The aim of the study is to investigate the optimum dyeing conditions for wool and cotton fabrics with the nettle (Urtica dioica L.) extract. For this purpose, the leaves of the nettle were extracted with distilled water by using Soxhlet apparatus. Wool and cotton fabrics were pretreated with artificial animal urine system (AAUS) including NH₃ (3%, v/v), CaC₂O₄ (3%, m/v), and urea (3%, m/v) before dyeing processes in order to improve the fastness properties of the dyed samples. The best dyeing conditions were evaluated in terms of color strength. The results reveal that the nettle leaves shall probably be an important raw material especially for dyeing of wool fibers.