316 research outputs found
Sensitizing Efficiency of Some Added Metal Salts on the Thermal and Explosive Characteristics of Hydrazenium Monoperchlorate and Hydrazenium Diperchlorate
Sensitivity to heat, impact and friction of hydrazenium-monoperchlorate and hydrazenium-diperchlorate have been investigated and the sensitizing efficiency of some added metal salts evaluated. The thermal sensitizing efficiency of the additives follow the order CuCrO/sub 4/ > CuCl/sub 2/ >NiO > Fe/sub 2/O/sub 3/ > MgO. The activation energy values obtained from explosion delay time are comparable with the values reported for thermal decomposition studies and are close to the activation energy value for thermal decomposition studies and are close to the activation energy value for thermal decomposition of anhydrous perchloric acid. The F of I values for these compounds are in the range reported for common initiatory explosives and are of the same order as that for mercury fulminate
Production and growth of cultchless oyster spat of Crassostrea madrasensis (Preston) for single oyster culture
In India, edible oyster (Crassostrea madrasensis)
farming is being practised by several farmers in
central Kerala employing the rack and ren method
in the estuaries and backwaters. However, farmed
oysters do not find ready marketability due to the
high labour costs involved in handling and shucking.
The Central Marine Fisheries Research Institute,
Cochin, Kerala, has developed the hatchery
technology for edible oyster spat production, both
cultched and cultchless. Nevertheless, these have
not been commercialised due to the fact that spat
collection from wild is still the most feasible option in
oyster farming. The aim of the present study was to
produce cultchless spat in the farm site itself and
rear it to commercial size for harvesting uniform sized
regular, rounded single oysters
Economy, Movement Dynamics, and Muscle Activity of Human Walking at Different Speeds
The complex behaviour of human walking with respect to movement variability, economy and muscle activity is speed dependent. It is well known that a U-shaped relationship between walking speed and economy exists. However, it is an open question if the movement dynamics of joint angles and centre of mass and muscle activation strategy also exhibit a U-shaped relationship with walking speed. We investigated the dynamics of joint angle trajectories and the centre of mass accelerations at five different speeds ranging from 20 to 180% of the predicted preferred speed (based on Froude speed) in twelve healthy males. The muscle activation strategy and walking economy were also assessed. The movement dynamics was investigated using a combination of the largest Lyapunov exponent and correlation dimension. We observed an intermediate stage of the movement dynamics of the knee joint angle and the anterior-posterior and mediolateral centre of mass accelerations which coincided with the most energy-efficient walking speed. Furthermore, the dynamics of the joint angle trajectories and the muscle activation strategy was closely linked to the functional role and biomechanical constraints of the joints
Synthesis of surfactant free stable nanofluids based on barium hexaferrite by pulsed laser ablation in liquid
Barium hexaferrite nanofluids based on five different solvents have been prepared by employing Pulsed Laser Ablation in Liquid (PLAL) at two different wavelengths of 532 nm and 1064 nm. They were then characterized using Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), UV-Vis spectroscopy, and Vibrating Sample Magnetometry (VSM). The chemical states of the ablated nanoparticles were identified from XPS analysis and found to be matching with that of the target. The crystallinity of the nanoparticles were confirmed from high resolution TEM (HRTEM) images and SAED patterns. It is found that different liquid environments lead to the formation of barium ferrite nanoparticles with different particle diameters. The plausible mechanism involved in this process is discussed. This study can pave way for the synthesis of stable magnetic nanofluids of permanent magnets. Further, this technique could be utilized for tailoring the morphology of nanoparticles with a judicious choice of the solvents and other ablation parameter
Simulation of flow diversion in cerebral aneurysms
Intracranial aneurysms are abnormal focal enlargements of the vascular walls that necessitate surgical intervention once detected. Emerging stent technology involves an innovative type of finely-braided stents, called flow diverters, which abruptly impede the arterial flow into the aneurysm, upon deployment, and induce thrombosis, vascular remodelling and complete aneurysm occlusion in under a year [1]. The understanding of the dynamics of blood flow within this radically modified environment is thought to be pivotal in increasing the efficacy of both stent design and prolonged treatment. The aim of this study is to numerically simulate the blood flow within stented arterial segments and to evaluate critical hemodynamic factors around the aneurysm neck, validated with clinical and experimental data [1,2]. These objectives create many geometric challenges around the flow diverter due to the tessellation and resolution of features with very large ratio (artery-to-stent) in the input i.e., medical images and stent models. Following a novel Body-Centric Cubic (BCC) mesh generation method [2], high-fidelity tetrahedral meshes of aneurysmal dilatations that incorporate flow diverters across the aneurysm neck are now possible with an accurate image- to-mesh (I2M) conversion scheme from micro-CT images (Fig. 1a,b). Preliminary results involve arterial segments both with and without flow diverters (Fig.1c), utilising the CFD software OpenFOAM® to solve the incompressible Navier-Stokes equations, under steady and physiologically-correct pulsatile flow conditions
Racial differences in the systemic inflammatory response to prostate cancer
Systemic inflammation may increase risk for prostate cancer progression, but the role it plays in prostate cancer susceptibility is unknown. From a cohort of over 10,000 men who had either a prostate biopsy or transurethral resection that yielded a benign finding, we analyzed 517 incident prostate cancer cases identified during follow-up and 373 controls with one or more white blood cell tests during a follow-up period between one and 18 years. Multilevel, multivariable longitudinal models were fit to two measures of systemic inflammation, neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-lymphocyte ratio (MLR), to determine NLR and MLR trajectories associated with increased risk for prostate cancer. For both measures, we found no significant differences in the trajectories by case/control status, however in modeling NLR trajectories there was a significant interaction between race (white or Black and case-control status. In race specific models, NLR and MLR values were consistently higher over time among white controls than white cases while case-control differences in NLR and MLR trajectories were not apparent among Black men. When cases were classified as aggressive as compared to non-aggressive, the case-control differences in NLR and MLR values over time among white men were most apparent for non-aggressive cases. For NLR among white men, significant case-control differences were observed for the entire duration of observation for men who had inflammation in their initial prostate specimen. It is possible that, among white men, monitoring of NLR and MLR trajectories after an initial negative biopsy may be useful in monitoring prostate cancer risk
A phase II study of the bispecific antibody MDX-H210 (anti-HER2 × CD64) with GM-CSF in HER2+ advanced prostate cancer
The proto-oncogene HER2 presents a novel therapeutic target. We report results in 25 patients with HER2+ advanced prostate cancer treated with the bispecific antibody MDX-H210 15 μg m−2by intravenous infusion plus GM-CSF 5 μg kg−1day−1by subcutaneous injection for 4 days repeated weekly for 6 weeks. Patients with stable disease or better received further cycles of treatment until disease progression or study withdrawal. 1 patient received no treatment and 4 received less than 1 cycle and are included in the toxicity analysis only. Median duration of follow up was 105+ (range 21–188) days. Toxicity was generally NCI-CTG 0–2. There were 2 grade 4 adverse events (heart failure and dyspnoea) and 1 grade 3 event (allergic reaction) resulting in discontinuation of the study medication. There were 9 further grade 3 events not resulting in trial withdrawal. There were no treatment-related deaths. 7/20 (35%) evaluable patients had a >50% PSA response of median duration 128 (range 71–184+) days. 7/12 (58%) patients with evaluable pain had improvements in pain scores. The PSA relative velocity on therapy decreased in 15/18 (83%) assessable patients compared to pre-study. GM-CSF and MDX-H210 is active in hormone refractory prostate carcinoma with acceptable toxicity; further studies are warranted. © 2001 Cancer Research Campaign http://www.bjcancer.co
Molecular dynamics simulation of the early stages of the synthesis of periodic mesoporous silica
We present results of detailed atomistic modeling of the early stages of the synthesis of periodic mesoporous silica using molecular dynamics. Our simulations lead to the proposal of a mechanism that validates several previous experimental and modeling studies and answers many controversial issues regarding the synthesis of mesoporous silicas. In particular, we show that anionic silicates interact very strongly with cationic surfactants and, significantly adsorb on the surface of micelles, displacing a fraction of previously bound bromide counterions. This induces an increase in micelle size and also enhances silica condensation at the micelle surface. The presence of larger silica aggregates in solution further promotes the growth of micelles and, by binding to surfactant molecules in different micelles, their aggregation. This work demonstrates the crucial role played by silica in influencing, by way of a cooperative templating mechanism, the structure of the eventual liquid-crystal phase, which in turn determines the structure of the porous material
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