In-situ SEM observation on fracture behavior of austempered silicon alloyed steel

Crack initiation,propagation and microfracture processes of austempered high silicon cast steel have been investigated by using an in-situ tensile stage installed inside a scanning electron microscope chamber. It is revealed that micro cracks always nucleate at the yielding near imperfections and the boundary of matrix-inclusions due to the stress concentration. There are four types of crack propagations in the matrix:crack propagates along the boundary of two clusters of bainitic ferrite;crack propagates along the boundary of ferrite-austenite in bainitic ferrite laths;crack propagates into bainitic ferrite laths;crack nucleates and propagates in the high carbon brittle plate shape martensite which is transformed from some blocky retained austenite due to plastic deformation.Based on the observation and analysis of microfracture processes,a schematic diagram of the crack nucleation and propagation process of high silicon cast steel is proposed.     

Additive Benefits of Radium-223 Dichloride and Bortezomib Combination in a Systemic Multiple Myeloma Mouse Model

Osteolytic bone disease is a hallmark of multiple myeloma (MM) mediated by MM cell proliferation, increased osteoclast activity, and suppressed osteoblast function. The proteasome inhibitor bortezomib targets MM cells and improves bone health in MM patients. Radium-223 dichloride (radium-223), the first targeted alpha therapy approved, specifically targets bone metastases, where it disrupts the activity of both tumor cells and tumor-supporting bone cells in mouse models of breast and prostate cancer bone metastasis. We hypothesized that radium-223 and bortezomib combination treatment would have additive effects on MM. In vitro experiments revealed that the combination treatment inhibited MM cell proliferation and demonstrated additive efficacy. In the systemic, syngeneic 5TGM1 mouse MM model, both bortezomib and radium-223 decreased the osteolytic lesion area, and their combination was more effective than either monotherapy alone. Bortezomib decreased the number of osteoclasts at the tumor–bone interface, and the combination therapy resulted in almost complete eradication of osteoclasts. Furthermore, the combination therapy improved the incorporation of radium-223 into MM-bearing bone. Importantly, the combination therapy decreased tumor burden and restored body weights in MM mice. These results suggest that the combination of radium-223 with bortezomib could constitute a novel, effective therapy for MM and, in particular, myeloma bone disease.     

Modeling of the enantioselective hydrogenation of 1-phenyl-1,2-propanedione over Pt/Al2O3 catalyst

A kinetic model was developed for the enantioselective hydrogenation of 1-phenyl-1,2-propanedione based on parallel racemic and enantioselective routes in the presence of cinchonidine. The Langmuir–Hinshelwood type of competitive adsorption approach was used in the model, which was combined with a batch reactor model. The proposed model could sufficiently describe the observed kinetic results.     

Esterification of propionic acid under microwave irradiation over an ion-exchange resin

Esterification of propionic acid with ethyl alcohol over an ion-exchange resin catalyst was studied under microwave dielectric heating. Experiments were carried out in a single-mode microwave loop reactor, equipped with a heating band as well to directly compare the efficiency of the conventional convective/conductive heating and microwave dielectric heating. Series of kinetic experiments were carried out with both conventional and dielectric heating at the reaction temperature of 105 °C and total pressure of 7 bar. Different initial molar ratios of propionic acid-to-ethanol (from 1:2 to 2:1) were investigated. Initial molar ratios of acid-to-alcohol significantly affected the final yield of the desired product ethyl ester of propionic acid, ethyl propionate. The highest product yield was observed with equimolar initial ratio, compared to 1:2 and 2:1 initial molar ratios of acid-to-alcohol. However, the kinetics and equilibrium of this reaction were unaffected by the method of heating (microwave or conventional).     

Effects of defatted dried roselle (Hibiscus sabdariffa L.) seed powder on lipid profiles of hypercholesterolemia rats

BACKGROUND: In vivo investigations were made of the effect of defatted dried roselle seed powder (DRS) on the lipid profiles of rats with induced hypercholesterolemia. The two‐batch sample consisted of 23 and 20 Sprague‐Dawley male rats randomly divided into four groups and fed with four different diets. The first batch of rats was fed with normal, hypercholesterol, hypercholesterol + 10 g kg^?1 (w/w) DRS and hypercholesterol + 20 g kg^?1 (w/w) DRS diets. The second batch of rats was fed with normal, hypercholesterol, hypercholesterol + 50 g kg^?1 (w/w) DRS and hypercholesterol + 150 g kg^?1 (w/w) DRS diets. Treatments were given for a total of 5 weeks. RESULTS: Results indicated that the addition of 10 g kg^?1 and 20 g kg^?1 of DRS did not significantly lower the plasma total cholesterol (TC) levels. In contrast, 50 g kg^?1 and 150g kg^?1 DRS significantly lowered (P < 0.05) the TC and low density lipoprotein cholesterol (LDL‐C) levels. CONCLUSION: The addition of 50 g kg^?1 and 150 g kg^?1 DRS showed potential hypocholesterolemic effects. Furthermore, these findings indicated that protein, lipid and dietary fibre were high in the seed powder. Copyright © 2008 Society of Chemical Industry     

Clinical experience of transurethral collagen injections for urinary stress incontinence--analysis of subjective symptoms

We evaluated the results of transurethral collagen injections for urinary stress incontinence. Twenty five women (mean age was 61.3 years) with urinary incontinence were treated with transurethral collagen injections using local or spinal anesthesia. The mean follow-up was 11.7 months (range 2 to 30). We examined the results based on subjective symptoms for incontinence. We could judge convalescence efficacy to some degree 1 month after operation, but patient age, type of stress incontinence, pad test and volume of collagen were not significantly different between patients who were cured and those not cured. Of the patients who needed injections more then 2 times, treatment was effective in type III patients. The patients whose symptoms were improved 3 months after operation wanted a re-operation when their incontinence recurred. Injection of transurethral collagen appears to be a safe and effective method for treating urinary incontinence. This procedure is a first choice for urinary incontinence.     

The use of computer simulation in the pulp and paper industry

Pulp and paper mill processes have certain typical features in common with other simulation objects. However, computer simulation can serve as a useful tool in the design and construction of process units and the entire mill, as well as comparison of various production and control strategies of the pulp and paper mill processes. Simulation problems in this area are related to the adjustment of simulation models to mill material balances with many recycles. When the internal behaviour of the processes are considered the lack of sufficiently complete or applicable models sets a limitation on simulation studies.     

UWB radio module design for wireless sensor networks

In this paper, we describe an impulse-based ultra wideband (UWB) radio system for wireless sensor network (WSN) applications. Different architectures have been studied for base station and sensor nodes. The base station node uses coherent UWB architecture because of the high performance and good sensitivity requirements. However, to meet complexity, power and cost constraints, the sensor module uses a novel non-coherent architecture that can autonomously detect the UWB signals. The radio modules include a transceiver block, a baseband processing unit and a power management block. The transceiver block includes a Gaussian pulse generator, a multiplier, an integrator and timing circuits. For long range applications, a wideband low noise amplifier (LNA) is included in the transceiver of the sensor module, whereas in short range applications it is simply eliminated to further reduce the power consumption. In order to verify the proposed system concept, circuit level implementation is studied using 1.5 V 0.18 μm CMOS technology. Finally, the UWB radio modules have been designed for implementation in liquid-crystal-polymer (LCP) based System-on-Package (SoP) technology for low power, low cost and small size integration. A small low cost, double-slotted, Knight’s helm antenna is embedded in the LCP substrate, which shows stable characterization and a return loss better than ?10 dB over the UWB band.     

Transesterification of trimethylolpropane and rapeseed oil methyl ester to environmentally acceptable lubricants

Biodegradable trimethylolpropane [2-ethyl-2-(hydroxymethyl)-1,3-propanediol] esters of rapeseed oil fatty acids were synthesized by transesterification with rapeseed oil methyl ester both by enzymatic and chemical means, both in bench and pilot scales. Nearly complete conversions were obtained with both techniques. A reduced pressure of about 2 to 5 kPa, to remove the methanol formed during transesterification, was critical for a high product yield. The quantity of added water was also critical in the biocatalysis. Candida rugosa lipase was used as biocatalyst and an alkaline catalyst in chemical transesterifications. In biocatalysis the maximum total conversion to trimethylolpropane esters of up to 98% was obtained at 42°C, 5.3 kPa, and 15% added water. The maximum conversion of about 70% to the tri-ester was obtained at the slightly higher temperature of 47°C. The reaction time was longer in the biocatalysis, but considerably higher temperatures were required in chemical synthesis. In the chemical synthesis tri-ester yields increased when the temperature was first held at 85 to 110°C for 2.5 h and subsequently increased to up to 120°C for 8 h. The trimethylolpropane esters obtained were tested as biodegradable hydraulic fluids and compared to commercially available hydraulic oils. The hydraulic fluids based on trimethylolpropane esters of rapeseed oil had good cold stability, friction and wear characteristics, and resistance against oxidation at elevated temperatures.