1,341 research outputs found
Importance of etiologic diagnosis of hydrocephalus as illustrated by a case of Walker Warburg syndrome
This article does not have an abstract
Magnetic resonance methods for studying intact spermatozoa
Motility is used as a routine parameter for assessing spermatozoa activity. The quality rating techniques adopted are based on electron or optical microscopy. However, these methods depend on gross structural and dynamical features of sperm cells and do not provide information on metabolic activity of intact cells. Lately, biochemical assays have become popular. Such methods are cumbersome and destroy the samples. Magnetic resonance methods offer a non-invasive method for studies on intact sperms. We have investigated respiration, maturation andin vitro capacitation of sperms from human ejaculates and sperms extracted from goat reproductive organ using electron spin resonance spin labelling and [31P] nuclear magnetic resonance methods. These studies clearly establish the advantages of magnetic resonance in studies related to metabolic activity of sperms
Immobilization of glucose oxidase with polyurethane on carbon support
Glucose oxidase (GOD) has been immobilized by physical entrapment on polyurethane PU-6 matrix. It has been found that the enzyme acquires greater thermal stability on immobilization. Oxygen acts as a co-substrate for the redox reaction. However, maintaining oxygen concentration constant throughout the experiment is a difficult task. To overcome this we have coimmobilized ferrocene, which can act as an electron acceptor. 31P NMR results indicate that ferrocene is located in the close proximity of the active site of GOD. Moreover, simultaneous use of mediators such as ferricyanide, phenazine methosulphate or flavine mononucleotide have been found to facilitate electron transfer. Platinum, apart from being an expensive metal, is likely to exhibit adverse toxic effects during prolonged 'in-vivo' applications. Electrodes prepared using carbon in the place of platinum, show comparably good response. This opens a new possibility for making cheaper and biocompatible sensors
Prospective study of fracture calcaneus with Allan’s procedure- bone grafting without implants
Background: Calcaneum is usually fractured following high energy axial traumas such is seen in cases of fall from height or road traffic accidents. If not properly managed these fractures can be a cause of prolonged morbidity in the form of pain, stiffness and deformities. We have conducted this prospective study of fracture calcaneum with the method described by Allan et al which constitute of open reduction and bone grafting without any implants. The objective of the was to determine the clinical approach, described by Allan et al for treatment of fracture calcaneum and to discuss in short the results, pitfalls and challenges associated with this.Methods: A prospective study was done on 42 patients who were diagnosed with intra-articular calcaneal fractures depending upon a predefined inclusion and exclusion criteria. All fractures of the study subjects were treated using a lateral approach by Allan’s procedure. Final outcome was assessed on the basis modified Rowe score.Results: In this study a total of 42 patients with intra-articular calcaneal fractures and treated by open reduction and bone grafting without any implants were studied. There were 36 men and 6 women. Majority of the patients tolerated the procedure well and most of the patients (95.23%) had a complete or partial restoration of heel shape. Significant residual pain was seen in only 1 (2.38 %) patient. 36 patients (85.71 %) had excellent outcome 5 patients (11.90%) had good and 1 patient (2.38%) had satisfactory outcome. Conclusions: The management of intra-articular calcaneal fracture by open reduction and bone grafting without any implants give good results with excellent functional outcome. Since no implants are used in this technique this can be a preferable procedure in rural areas and in patients with low socioeconomic status.
Peptide induced polymorphism in model membranes
Lipids in biological membranes generally adopt bilayer structures. However, incorporation of peptides may induce alterations in such structures. We have studied the influence of tryptophan, leucine, Trp-Leu, luteinizing hormone releasing hormone and renin inhibitor peptide on lipid organisation in liposomes. It has been observed that the effect is specific to the peptide molecule as-a whole and does not have direct correlation to the constituent amino acids or the conformation of the molecule
Simplified Burn-Rate Model for CMDB Propellants
A single model has been proposed to predict the burning rates of bimodal AP,RDX and aluminum containing CMDB propellants. This is done in terms of the respective physical constants on the basis of a recently developed model of combustion of CMDB propellants. The study has been carried out to examine the effects of changes in propellants composition, AP particle size and pressures on burning rate. Computer programs were developed for this purpose and the results obtained for typical sets of input data have been presented and compared with the actual results
Surrogate regression modelling for fast seismogram generation and detection of microseismic events in heterogeneous velocity models
This is the author accepted manuscript. The final version is available from Oxford University Press (OUP) via the DOI in this record.Given a 3D heterogeneous velocity model with a few million voxels, fast generation of accurate seismic responses at specified receiver positions from known microseismic event locations is a well-known challenge in geophysics, since it typically involves numerical solution of the computationally expensive elastic wave equation. Thousands of such forward simulations are often a routine requirement for parameter estimation of microseimsic events via a suitable source inversion process. Parameter estimation based on forward modelling is often advantageous over a direct regression-based inversion approach when there are unknown number of parameters to be estimated and the seismic data has complicated noise characteristics which may not always allow a stable and unique solution in a direct inversion process. In this paper, starting from Graphics Processing Unit (GPU) based synthetic simulations of a few thousand forward seismic shots due to microseismic events via pseudo-spectral solution of elastic wave equation, we develop a step-by-step process to generate a surrogate regression modelling framework, using machine learning techniques that can produce accurate seismograms at specified receiver locations. The trained surrogate models can then be used as a high-speed meta-model/emulator or proxy for the original full elastic wave propagator to generate seismic responses for other microseismic event locations also. The accuracies of the surrogate models have been evaluated using two independent sets of training and testing Latin hypercube (LH) quasi-random samples, drawn from a heterogeneous marine velocity model. The predicted seismograms have been used thereafter to calculate batch likelihood functions, with specified noise characteristics. Finally, the trained models on 23 receivers placed at the sea-bed in a marine velocity model are used to determine the maximum likelihood estimate (MLE) of the event locations which can in future be used in a Bayesian analysis for microseismic event detection.This work has been supported by the Shell Projects and Technology. The Wilkes high performance GPU computing service at the University of Cambridge has been used in this work
Studies on Some New Ru(III) Complexes Using aryl-azo Pentane- 2,4-dione and 2,6-bis (2'-Benzimidazolyl) Pyridine as Ligands: Synthesis, Spectroscopic, Luminescent, Electrochemical and Biological Activities
Some ruthenium(III) complexes with aryl-azo 2,4-pentanedione as co-ligands (L1H - L3H2) have been synthesized and characterized spectroscopically IR, 1H NMR, UV/Vis, ESR, conductimetric)
along with elemental analysis and FAB-mass data. Their luminescent and redox properties have
been studied. The antibacterial, anti-HIV and antitmnour activities have also been reported
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