305 research outputs found
Small intestinal deficit in pellagra
Twenty-four persons with pellagra were the subjects of absorption testing. Fourteen (58.3%) showed evidence of defective absorption of two or three absorption tests and eight showed (33.3%) abnormality of only one of the tests of absorption. Only two cases (8.3%) were found to be having completely normal absorptive status of the small bowel. Six of these fourteen (42.8%) cases recovered completely or partially on treatment with nicotinic acid. The etiopathogenesis of malabsorption in pellagra is discussed. Patients of both primary as well as secondary pellagra showed similar derangement of small intestinal functions
Localized Surface Plasmon Resonance Studies on Pd/C Nano-Composite System: Effect of Metal Concentration and Annealing Temperature
The effects of metal concentration and annealing temperature on the localized surface plasmon resonance (LSPR) properties of the Pd nanoparticles (NP) dispersed in carbon were investigated. The Pd/C nano-composite thin films with 7 to 39 atomic % concentration of metal content were deposited using the atom beam co-sputtering techniques and subjected to annealing at temperature varying from 300 degrees C to 600 degrees C. The UV-vis spectroscopy studies on as-prepared films displayed a Mie scattering profile, but not well-defined LSPR bands were observed for all the values of Pd concentration. This is attributed to the smaller size (3-4 nm) of Pd NPs and rough Pd/C interface, as confirmed from TEM studies. When samples were annealed at a temperature of 300 degrees C, three broad LSPR absorption bands in the visible region, along with a sharp peak at 210 nm, were observed and the effect of Pd concentration variation was insignificant on their position. The multiple LSPR bands were observed due to agglomeration NPs, which is consistent with earlier reports and is also observed in the TEM images. When annealing temperature was subsequently increased to 500 degrees C, a blue shift in the LSPR peak position with an increase in the Pd concentration was observed, which phenomena is attributed to the formation of bigger NPs with the formation of sharp NPs-interface at high temperature upon annealing. A monotonic increase in the magnitude and decrease in the FWHM with an increase in concentration suggested change in the dielectric function of sample due to the growth of NPs. This is further confirmed from XRD studies, where strain relaxation and grain growth were observed. The intensity of the SPR peak decreased with an increase in the annealing temperature. The LSPR peak disappeared on annealing at a temperature of 600 degrees C, suggesting the formation of continuous polycrystalline thin films of Pd. In summary, NPs size, metal matrix interface, and concentration of metal play key roles in the tailoring the LSPR properties of the Pd
Interaction of oxygen (O+7) ion beam on polyaniline thin films
High-energy ion beam irradiation of the polymers is a good technique to modify the properties
such as electrical conductivity, structural behaviour and mechanial properties. Polyaniline thin films doped with
hydrochloric acid (HCl) were prepared by oxidation of ammonium persulphate. The effect of Swift Heavy Ions
irradiation on the electrical and structural properties of polyaniline has been measured in this study. Polyaniline
films were irradiated by oxygen ions (energy 80 MeV, charge state O+7) with fluence varying from 1 × 1010 to 3
× 1012 ions/cm2. The studies on electrical and structural properties of the irradiated polymers were investigated
by measuring V-I using four probe set-up and X-ray diffraction (XRD) using Bruker AXS, X-ray powder
diffractometer. V-I measurements shows an increase in the conductivity of the film, XRD pattern of the polymer
shows that the crystallinity improved after the irradiation with Swift Heavy Ions (SHI), which could be attributed
to cross linking mechanism.Subhash Chandra1*, S Annapoorni2, R G Sonkawade3, P K Kulriya3 Fouran Singh3,
D K Avasthi3, J M S Rana1 and R C Ramola1
1Department of Physics, H N B Garhwal University, Badshahi Thaul Campus,
Tehri Garhwal-249 199, Uttarakhand, India
2Department of Physics and Astrophysics, University of Delhi, Delhi-110 007, India
3Inter University Accelerator Center, Aruna Asaf Ali Marg, New Delhi-110 067, India
E-mail : [email protected] of Physics, H N B Garhwal University, Badshahi Thaul Campus,
Tehri Garhwal-249 199, Uttarakhand, India
Department of Physics and Astrophysics, University of Delhi, Delhi-110 007, India
Inter University Accelerator Center, Aruna Asaf Ali Marg, New Delhi-110 067, Indi
Swift Heavy Ion Induced Modification Studies of C60 Thin Films
Modification induced by 110 MeV Ni ion irradiated thin film samples of C60 on
Si and quartz substrates were studied at various fluences. The pristine and
irradiated samples were investigated using Raman spectroscopy, electrical
conductivity and optical absorption spectroscopy. The Raman data and band gap
measurements indicate that swift ions at low fluences result in formations that
involve multiple molecular units like dimer or polymer. High fluence
irradiation resulted in sub-molecular formations and amorphous semiconducting
carbon, indicating overall damage of the fullerene molecules. These
sub-molecular units have been identified with nanocrystalline diamond and
nanocrystalline graphite like formations.Comment: 7 pages, 29 references and 9 figures submitted to J. Appl. Phy
- …