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Biomedical subjects

S Mohan

Publications and source records attributed to S Mohan.

At least 37 records · Page 2Linked to original sources
PubMed2005

FT-Raman and FTIR spectra, assignments and ab initio calculations of 2-aminobenzyl alcohol.

The Fourier transform Raman and Fourier transform infrared spectra of 2-aminobenzyl alcohol (2ABA) were recorded in the solid phase. Geometry optimizations were done with out any constraint and harmonic vibrational wave numbers and several thermodynamic parameters were calculated for the minimum energy conformer at ab initio and DFT levels invoking 6-31g** and 6-311+g(2d, p) basis sets and the results were compared with the experimental values. With the help of three specific scaling procedures, the observed vibrational wavenumbers in FTIR and FT-Raman spectra were analyzed and assigned to different normal modes of the molecule. Most of the modes have wavenumbers in the expected range and the error obtained was in general very low. The appropriate theoretical spectrograms for the Raman and IR spectra of 2ABA were also constructed.

Benzyl Alcohols↗
PubMed2005

Caring for patients with cancer in non-specialist wards: the nurse experience.

This study aims to describe the experiences of nurses caring for cancer patients in non-specialist wards. The study was conducted in a large (420 beds) and small (32 beds) hospital in an area health service with urban and rural populations in the west of Sydney. A qualitative descriptive approach was utilized to collect data from the nurses. Data were collected using a survey and in-depth interviews of nurses working in non-specialist cancer wards. Transcribed data were managed with Nudist Vivo software and analysed for common themes using process of constant comparison and contrast. Twenty-five surveys were returned and five nurses volunteered to be interviewed. The six major themes that emerged from analysis of data were: emotional nature of care, lack of time, lack of knowledge of cancer treatment, family support, environment not conducive to proper care and dealing with patient's non-acceptance of cancer diagnosis. The nurses in this study wished to provide quality supportive care for cancer patients and their families but the inconducive environment and inadequate relevant training hindered the nurses' efforts. This then presents further need of relevant training for nurses in cancer care and time management, to meet up with these challenges.

Attitude to Health↗
PubMed2005

ZnO nanowires by pulsed laser vaporization: synthesis and properties.

We report a new pulsed-laser vaporization (PLV) technique to synthesize nanowires of single-crystal ZnO having a wurtzite structure by using colloidal gold nanoparticles as seeding catalysts. The average diameter of the nanowires is approximately 13 nm, with a very narrow range of 7 to 25 nm. The nanowires are straight for the most part, with the axes parallel to the [0001] growth direction. Raman and photoluminescence spectra from the nanowires and bulk ZnO are similar except for a approximately 510 nm band in the nanowires due to oxygen vacancies. The bulk-like vibrational and electronic properties of the nanowires is due to the diameter being larger than the threshold below which quantum confinement-induced effects are expected.

Crystallization↗
PubMed2005

Impaired skeletal growth in mice with haploinsufficiency of IGF-I: genetic evidence that differences in IGF-I expression could contribute to peak bone mineral density differences.

Although it is well established that there is considerable inter-individual variation in the circulating levels of IGF-I in normal, healthy individuals and that a genetic component contributes substantially to this variation, the direct evidence that inter-individual variation in IGF-I contributes to differences in peak bone mineral density (BMD) is lacking. To examine if differences in IGF-I expression could contribute to peak BMD differences, we measured skeletal changes at days 23 (prepubertal), 31 (pubertal) and 56 (postpubertal) in mice with haploinsufficiency of IGF-I (+/-) and corresponding control mice (+/+). Mice (MF1/DBA) heterozygous for the IGF-I knockout allele were bred to generate +/+ and +/- mice (n=18-20 per group). Serum IGF-I was decreased by 23% (P<0.001) in mice with IGF-I haploinsufficiency (+/-) group at day 56 compared with the control (+/+) group. Femoral bone mineral content and BMD, as determined by dual energy X-ray absorptiometry, were reduced by 20% (P<0.001) and 12% respectively in the IGF-I (+/-) group at day 56 compared with the control group. The peripheral quantitative computed tomography measurements at the femoral mid-diaphysis revealed that periosteal circumference (7%, P<0.01) and total volumetric BMD (5%, P<0.05) were decreased significantly in the +/- group compared with the +/+ group. Furthermore, serum IGF-I showed significant positive correlations with both areal BMD (r=0.55) and periosteal circumference (r=0.66) in the pooled data from the +/+ and +/- groups. Our findings that haploinsufficiency of IGF-I caused significant reductions in serum IGF-I level, BMD and bone size, together with the previous findings, are consistent with the notion that genetic variations in IGF-I expression could, in part, contribute to inter-individual differences in peak BMD among a normal population.

Absorptiometry, Photon↗
PubMed2004

2-[(E)-(4-Chlorophenyl)methyleneamino]-N-(X-methylphenyl)-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide, where X = 2 and 3.

The title compounds, both C(23)H(21)ClN(2)OS, are isomeric, with (I) and (II) being the N-3-methylphenyl and N-2-methylphenyl derivatives, respectively. The dihedral angle between the 4-chlorophenyl group and the thiophene ring in (II) [38.1 (1) degrees ] is larger than that in (I) [7.1 (1) degrees ], indicating steric repulsion between the chlorophenyl and o-toluidine groups in (II). In both compounds, an intramolecular N-H...N hydrogen bond forms a pseudo-six-membered ring, thus locking the molecular conformation. In the crystal structures, molecules are connected via N-H...O hydrogen bonds, forming chains along the b axis in (I) and along the c axis in (II). Intermolecular C-H...O/S and pi-pi interactions are also observed in (II), but not in (I).

Journal Article↗
PubMed2004

Two biologically active thiophene-3-carboxamide derivatives.

The compounds 2-[[(E)-(4-methoxyphenyl)methylene]amino]-N-(3-methylphenyl)-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide, C24H24N2O2S, (I), and N-(4-methylphenyl)-2-[[(E)-(4-methylphenyl)methylene]amino]-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide, C24H24N2OS, (II), show antibacterial and antifungal activities. The m-toluidine ring in (I) and the p-toluidine ring in (II) are coplanar with their respective thiophene rings. In (I), an intermolecular C-H...O hydrogen bond is present, whereas (II) does not exhibit any significant intermolecular interactions. However, in both compounds, an intramolecular N-H.N hydrogen bond forms a pseudo-six-membered ring, thus locking the molecular conformation and eliminating conformational flexibility.

Amides↗
PubMed2004

Protein-enriched pea flour extract protects stored milled rice against the rice weevil, Sitophilus oryzae.

Studies were conducted to evaluate the effect of a protein-enriched pea (Pisum sativum var. Bonneville) flour extract against the rice weevil, Sitophilus oryzae in its repellency, toxicity, effect on fecundity, stability and sensory properties. Milled rice admixed with pea flour extract at 1% concentration significantly repelled S. oryzae. Mortality of S. oryzae was found to increase and fecundity was markedly suppressed, in rice treated with 1% pea flour extract. The toxicity and reproductive effects of the pea protein-enriched rice were found to be stable for a period of 5 months. The sensory characteristics of stored rice when eaten were not affected by the treatment with pea flour extract. This study indicates that the protein-enriched flour extract obtained from the Bonneville pea may be feasible to protect stored milled rice from insect attack.

Animals↗
PubMed2004

Mapping quantitative trait loci that influence blood levels of alkaline phosphatase in MRL/MpJ and SJL/J mice.

To examine the hypothesis that serum alkaline phosphatase (ALP) levels have a heritable component, we analyzed blood from two inbred strains of mice, MRL/MpJ and SJL, which exhibit 90% difference in total serum ALP activity (268+/-26 vs. 140+/-15 U/l, respectively, P<0.001). A genome-wide scan was carried out using 137 polymorphic markers in 518 F2 female mice. Serum ALP activity in the F2 progeny showed a normal distribution with an estimated heritability of 56%. Genome-wide scan for cosegregation of genetic marker data with serum ALP activity revealed three major quantitative trait loci (QTL), one each on chromosomes 2 (LOD score 3.8), chromosome 6 (LOD score 12.0), and chromosome 14 (LOD score 3.7). In addition, there was one suggestive QTL on chromosome 2 (LOD score of 3.3). In aggregate, these QTLs explain 22.5% of variance in serum ALP between these two strains. Serum ALP showed a moderate but significant correlation with body weight adjusted total body bone mineral density (r=0.12, P=0.0108) and periosteal circumference at midshaft tibia (r=0.15, P=0.0006) in F2 mice. The chromosome 6 locus harboring the major serum ALP QTL also contains a major BMD and bone size QTL, identified earlier, between these two strains of mice; in addition, this QTL is also close to the locus that regulates IGF-I levels (LOD score 8-9) in C3HB6 F2 mice. These common QTLs indicate that the observed difference in ALP and BMD or bone size may be regulated by same loci (or genes). Accordingly, the osteoblast cells isolated from femur and tibia of MRL mice showed a significantly higher number of ALP +ve cells/colony and two- to threefold higher ALP activity (P<0.001) as compared to the cells isolated from SJL mice, thus suggesting that differences in serum ALP between MRL and SJL reflect difference in ALP expression from osteoblasts from these strains of mice. These data suggest that serum ALP levels are genetically determined and correlate with cellular mechanisms that differentiate BMD accrual in these two strains of mice. The findings that ALP and BMD traits share the same loci on chromosome 6 suggest a role for genetic determinants of bone formation in overall BMD accretion.

Alkaline Phosphatase↗
PubMed2004

Spasmogenic effect of a Solanummelongena leaf extract on guinea pig tracheal chains and its possible mechanism(s).

The methanol extract of fresh leaves of Solanum melongena L. (Solanaceae) was evaluated for its capacity to alter the tone of isolated, pre-contracted guinea pig tracheal chains, as well as for its possible mechanism(s) of action. Using serial dilutions between 0.0025 and 2.5 mg/mL, the extract was found to cause a dose-dependent increase in the force of muscle contraction. The EC(50) value was 0.46 +/- 0.01 mg/mL. The concomitant use of acetylcholine 10(-5) M did not significantly affect the force of contraction induced by the extract. Histamine 10(-5) M added at about 40% to, and salbutamol 10(-6) M antagonized by about 30% its constrictive effect. Chlorpheniramine 10(-6) M, propanolol 10(-5) M, and nifedipine 10(-6) M did not significantly influence the extract-induced force of contraction, but atropine 3 x 10(-7) M reduced it by approximately 60%. These data suggest that the Solanum melongena extract exerted a bronchospasmogenic rather than a bronchospasmolytic effect, probably through muscarinic receptor stimulation.

Acetylcholine↗
PubMed2004

Synthesis, Fourier transform infrared and Raman spectra, assignments and analysis of N-(phenyl)- and N-(chloro substituted phenyl)-2,2-dichloroacetamides.

N-(phenyl)-2,2-dichloroacetamide (NPA) and N-(chloro substituted phenyl)-2,2-dichloroacetamides of the configuration XyC6H(5-y)-NHCO-CHCl2 (where, X = Cl and y = 1, 2 and 3) were synthesised and the Fourier transform infrared (FTIR) and Fourier transform Raman (FT-Raman) spectra of the compounds were recorded and analysed. The FTIR spectra of all the compounds were recorded in a Bruker IFS 66V spectrometer in the range of 4000-400 cm(-1) and the FT-Raman spectra were also recorded in the same instrument in the region 3500-100 cm(-1). The variation of an amide bond (-NHCO-) parameters with the substitution of the chlorine atom in the phenyl group and the mixing of different normal modes are discussed with the help of potential energy distribution (PED) calculated through normal co-ordinate analysis.

Acetamides↗
PubMed2004

Relationship between testosterone supplementation and insulin-like growth factor-I levels and cognition in healthy older men.

BACKGROUND: Our laboratory has previously reported that testosterone (T) administration to older men significantly improves cognitive function. This study examined potential changes in insulin-like growth factor (IGF) IGF-I, IGF-II and IGF-related binding proteins in response to T administration in older men and their relationship to cognitive functioning. METHODS: Twenty-five healthy community dwelling volunteers, ranging in age from 50-80 years were randomized to receive weekly intra-muscular (i.m.) injections of either 100 mg T enanthate or placebo (saline) for 6 weeks. Serum hormone levels and cognitive functioning was assessed at baseline and twice during treatment. RESULTS: Significant positive associations between IGF-I and IGF-II and spatial memory, spatial reasoning, and verbal fluency were observed after 6 weeks of T administration. Increased serum T levels from treatment were positively associated with improvement in spatial reasoning performance, whereas estradiol was associated with a decline in divided attention performance. Serum IGF-I, IGF-II and IGFBPs did not change in response to T treatment. CONCLUSIONS: Our results suggest that T, estradiol and IGF-I may have independent and selective effects on cognitive functioning. Positive associations between T levels and cognition are consistent with an effect of androgen treatment, whereas positive associations between IGF-I levels and cognition are reflective of a relationship between endogenous IGF-I levels and cognition.

Aged↗
PubMed2004

FTIR and FT Raman spectra and analysis of poly(4-methyl-1-pentene).

Poly(4-methyl-1-pentene) is the most widely used polymer in industry and medical products. Fourier transform infrared and Raman Spectra of poly(4-methyl-1-pentene) have been recorded in the range of 4000-400 and 4000-100 cm(-1), respectively. In the present investigation a detailed assignments of the observed fundamental bands of poly(4-methyl-1-pentene) has been analyzed in terms of peak positions and relative intensities. With the hope of providing more and effective information on the fundamental vibrations, a normal coordinate analysis has also been performed on poly(4-methyl-1-pentene) by assuming Cs symmetry. The simple general valence force field (SGVFF) method has been employed in normal coordinate analysis and the potential energy distribution (PED) has been calculated for each fundamental vibration. The PED contribution corresponding to each of the observed frequencies shows the reliability and accuracy of spectral analysis. The validity of the SGVFF method as a practical tool for complete analysis of vibrational spectra, for poly(4-methyl-1-pentene) is confirmed in the present work.

Models, Chemical↗
PubMed2004

FTIR and FTR spectral studies of 2-amino-6-bromo-3-formylchromone.

FTIR and FT-Raman spectra of 2-amino-6-bromo-3-formylchromone (ABFC) have been recorded, using Bruker IFS 66V spectrometer. A detailed vibrational spectral analysis carried out and assignments of the observed bands have been proposed on the basis of fundamentals, overtones and combinations, by assuming C(S) point group symmetry. A normal coordinate analysis has been performed to characterise the vibrational fundamentals in terms of potential energy distribution (PED).

Bromine↗