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

Double Isopropoxides of Hf(IV) with Alkaline Earth Metals

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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

Synthesis and LB film formation of fatty acid- fad complex

Flavin adenine dinucleotide can exist in two oxidation states. Switching from one state to the other can be achieved chemically or electrically. The flavin undergoes reduction reversibly by two one electron steps or one two electron step, changing the chemistry of the enediamine subfunction of the isoalloxazine moiety. The adenine moiety is not involved in the catalysis, but helps in anchoring the coenzyme at the active site. The hydrophilicity of FAD has been changed by chemically attaching hydrocarbon chains to the noncatalytic adenine moiety. The modified coenzyme has been verified to retain the electro chemical, optical and the biochemical properties. The amphiphilic molecules can form monolayers at the air-water interface. A film of desired thickness can be formed on a solid support by means of monomolecular deposition using LB film technique. The characterization of the film has been done using spectrophotometric and electrochemical methods

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

Exclusive light particle measurements for the system 19^{19}F + 12^{12}C at 96 MeV

Decay sequence of hot {31}^P nucleus has been investigated through exclusive light charged particle measurements in coincidence with individual evaporation residues using the reaction {19}^F (96 MeV) + {12}^C. Information on the sequential decay chain have been extracted by confronting the data with the predictions of the statistical model. It is observed from the present analysis that such exclusive light charged particle data may be used as a powerful tool to probe the decay sequence of the hot light compound systems.Comment: 13 pages, 8 figures, Physical Review C (in press

Entrance channel dependence in compound nuclear reactions with loosely bound nuclei

The measurement of light charged particles evaporated from the reaction 6,7Li+6Li has been carried out at extreme backward angle in the energy range 14 - 20 MeV. Calculations from the code ALICE91 show that the symmetry of the target-projectile combination and the choice of level density parameter play important roles in explaining the evaporation spectra for these light particle systems. In above barrier energy region the fusion cross-section is not suppressed for these loosely bound nuclei.Comment: 2 pages, 1 figur

Prevalence and correlates of microvascular complications among patients with diabetes mellitus: a cross sectional study

Background: Diabetes mellitus is a metabolic disorder of multiple etiology, characterized by chronic hyperglycemia and associated with various microvascular, macrovascular and nonvascular complications leading to increasing morbidity and mortality. Microvascular complications are daibetes specific and their relation with associated comorbidities studied worldwide. To estimate the prevalence of microvascular complications in diabetic patients and to find their relation with various comorbid conditions.Methods: A total of hundred diagnosed patients of diabetes mellitus with age ranging from 18 to 75 years were enrolled in the study. Patients were assessed for the presence of microvascular complications and associated comorbidities. The effect of various comorbidities on frequency of microvascular complications was also determined. Data collected was statistically analyzed.Results: In this study, the mean age of the study group was 55.77±11.75 years. Mean age of onset of the disease was 48.89±11.50 years. Mean duration of the disease in the study group was 6.86±5.02 years. Diabetic retinopathy, neuropathy and nephropathy was found in 76%, 63% and 69% patients, respectively. Among patients with hypertension, 91.7%, 83.3%, and 81.7% cases were found to have retinopathy, neuropathy and nephropathy, respectively. The corresponding figures for those with comorbid IHD were 91.1%, 83.9% and 76.8% respectively whereas among patients with coexisting metabolic syndrome, 92.5%, 80.6%, and 79.1% were found to have retinopathy, neuropathy, and nephropathy, respectively.Conclusions: The most frequent microvascular complication reported by this study was diabetic retinopathy. comorbid conditions like hypertension, ischemic heart disease, and metabolic syndrome were associated with higher prevalence of microvascular complications in diabetic patients

A tracked approach for automated NMR assignments in proteins (TATAPRO)

A novel automated approach for the sequence specific NMR assignments of 1HN, 13Cα, 13Cβ, 13C'/1Hα and 15N spins in proteins, using triple resonance experimental data, is presented. The algorithm, TATAPRO (Tracked AuTomated Assignments in Proteins) utilizes the protein primary sequence and peak lists from a set of triple resonance spectra which correlate 1HN and 15N chemical shifts with those of 13Cα, 13Cβ and 13C'/1Hα. The information derived from such correlations is used to create a 'master list' consisting of all possible sets of 1HN i, 15Ni, 13Cα i, 13Cβ i, 13C'i/1Hα i, 13Cα i-1, 13Cβ i-1 and 13C'i-1/ 1Hα i-1 chemical shifts. On the basis of an extensive statistical analysis of 13Cα and 13Cβ chemical shift data of proteins derived from the BioMagResBank (BMRB), it is shown that the 20 amino acid residues can be grouped into eight distinct categories, each of which is assigned a unique two-digit code. Such a code is used to tag individual sets of chemical shifts in the master list and also to translate the protein primary sequence into an array called pps array. The program then uses the master list to search for neighbouring partners of a given amino acid residue along the polypeptide chain and sequentially assigns a maximum possible stretch of residues on either side. While doing so, each assigned residue is tracked in an array called assig array, with the two-digit code assigned earlier. The assig_array is then mapped onto the pps array for sequence specific resonance assignment. The program has been tested using experimental data on a calcium binding protein from Entamoeba histolytica (Eh-CaBP, 15 kDa) having substantial internal sequence homology and using published data on four other proteins in the molecular weight range of 18-42 kDa. In all the cases, nearly complete sequence specific resonance assignments (> 95%) are obtained. Furthermore, the reliability of the program has been tested by deleting sets of chemical shifts randomly from the master list created for the test proteins

Confinement and electron correlation effects in photoionization of atoms in endohedral anions: Ne@C60^{z-}

Trends in resonances, termed confinement resonances, in photoionization of atoms A in endohedral fullerene anions A@C60^{z-} are theoretically studied and exemplified by the photoionization of Ne in Ne@C{60}^{z-}. Remarkably, above a particular nl ionization threshold of Ne in neutral Ne@C60 (I_{nl}^{z=0}), confinement resonances in corresponding partial photoionization cross sections sigma_{nl} of Ne in any charged Ne@C60^{z-} remain almost intact by a charge z on the carbon cage, as a general phenomenon. At lower photon energies, omega < I_{nl}^{z=0}, the corresponding photoionization cross sections develop additional, strong, z-dependent resonances, termed Coulomb confinement resonances, as a general occurrence. Furthermore, near the innermost 1s ionization threshold, the 2p photoionization cross section sigma_{2p} of the outermost 2p subshell of thus confined Ne is found to inherit the confinement resonance structure of the 1s photoionization spectrum, via interchannel coupling. As a result, new confinement resonances emerge in the 2p photoionization cross section of the confined Ne atom at photoelectron energies which exceed the 2p threshold by about a thousand eV, i.e., far above where conventional wisdom said they would exist. Thus, the general possibility for confinement resonances to resurrect in photoionization spectra of encapsulated atoms far above thresholds is revealed, as an interesting novel general phenomenon.Comment: 6 pages, 4 figures, Latex2e, jpconf.cls styl