225 research outputs found

    Understanding the Pathophysiology of Spinocerebellar Ataxias through genetics, neurophysiology, structural and functional neuroimaging

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    Over the past 10 years a large cohort of 656 index patients with clinically suspected degenerative ataxias were clinically evaluated under various research projects. Of these, 625 index patients underwent genetic tests for the clinically suspected most probable diagnosis. A diagnosis could be achieved in 218 patients (34.9%). Among these 218 index patients, 82 each were SCA1 and SCA2, 32 were SCA3, 4 were SCA12, and 18 were Friedreich's Ataxia. Thus among the Autosomal Dominant Ataxias (SCAs) there was equal prevalence of SCA1 and SCA2 (41% each) followed by SCA3 (16%) and SCA12 (2%). This high prevalence of SCA1 is in contrast to the available National and International literature. The rate of clinical disease progression, especially in SCA2, was dependent on the CAG repeat size, and may commence linearly from birth.Apart from cerebellar involvement, a comprehensive evaluation of the neuroaxis in various subsets of this genetically proved cohort showedsubclinicalinvolvement of the cerebral cortex, central motor and sensory pathways, peripheral nervous system and autonomic nervous system. Important findings include: (a)Amixedsensorimotor and pure sensory neuropathy was seen in all the three subtypes of SCAs, while pure motor neuropathy was uncommon; (b) There was reduced cortical excitability and prolonged central motor conduction time, most evident in SCA1 and least in SCA2; (c) Cardiac autonomic dysfunction, predominantly parasympathetic, was seen in SCA, and the severity correlated with the duration of illness in SCA1; (d) In SCA1 there was a global impairment of balance, with greater instability in anterior–posterior than medio–lateral directions; (e) In all the three SCAs there was a significant loss of gray matter in both cerebellar hemispheres and vermis. Vermian atrophy was more pronounced in SCA3, while SCA1 and SCA2 had significant white matter atrophy. Pontine white matter atrophy was more pronounced in SCA2; (f) Cerebellar activity was largely absent with additional activity in contralateral cortices and in thalami in patients with SCA1; increased thalamic function could be one of the causes for disinhibition of the motor cortex contributing to uncoordinated movements.Studies on larger cohort of each subtype of SCAs to validate the above findings, follow-up studies to determine the rate and nature of progression of neurodegeneration and evaluation of pre-symptomatic genetically confirmed SCAs will help understand the pathophysiology of the SCAs

    Total Ionization Cross Sections due to Electron Impact of Ammonia from Threshold to 10 MeV

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    In the present paper, we have employed modified Khare-BEB method [Atoms, (2019)] to evaluate total ionization cross sections by the electron impact for ammonia in energy range from the ionization threshold to 10 MeV.  The theoretical ionization cross sections have been compared to the available previous theoretical and experimental results. The collision parameters dipole matrix squared  and CRP  also have been calculated. The present calculations were found in remarkable agreement with the available experimental results

    Total Total Ionization Cross Sections due to Electron Impact of Carbon Tetrafluoride from Ionization Threshold to 10 MeV

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    Modified Khare-BEB model has been used to calculate the electron impact ionization cross section for carbon tetrafluoride (CF4) from ionization threshold to 10 MeV. The collisional parameters CRP and also has been  calculated. The calculations are compared with available experimental data . A good agreement is found among the present results, other previous calculations, and experimental data

    Luminescent quantum clusters of gold in transferrin family protein, lactoferrin exhibiting FRET

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    We report the synthesis of highly luminescent, water soluble quantum clusters (QCs) of gold, which are stabilized by an iron binding transferrin family protein, lactoferrin (Lf). The synthesized AuQC@Lf clusters were characterized using UV-Visible spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), photoluminescence (PL), matrix assisted laser desorption ionization mass spectrometry (MALDI-MS), FTIR spectroscopy and circular dichroism (CD) spectroscopy along with picosecond-resolved lifetime measurements. Detailed investigations with FTIR and CD spectroscopy have revealed changes in the secondary structure of the protein in the cluster. We have also studied Forster resonance energy transfer (FRET) occurring between the protein and the cluster. The ability of the clusters to sense cupric ions selectively at ppm concentrations was tested. The stability of clusters in widely varying pH conditions and their continued luminescence make it feasible for them to be used for intracellular imaging and molecular delivery, particularly in view of Lf protection

    Electrophoretic Studies of Biologically Important Mixed Metal – Ascorbic Acid –Nitrilotriacetate Complexes

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    Quantitative indication of a complex formation comes from the estimation of the stability or formation constants characterizing the equilibria corresponding to the successive addition of ligands. The binary equilibria of metal (II) / (III)–ascorbic acid and also mixed equilibria metal (II) / (III)–ascorbic acid–NTA have been studied using ionophoretic technique. The stability constants of metal–ascorbic acid binary complexes are found to be 103.77, 102.47,102.27 and that of metal–ascorbic acid–NTA mixed complexes have been found to be 106.05, 105.93, 105.75, for Fe(III), Cu(II) and Co(II) complexes, respectively at 25 °C and ionic strength Ic = 0.1 mol dm–3 (HClO4). (doi: 10.5562/cca1778

    Chemical potential shift and gap-state formation in SrTiO3δ_{3-\delta} revealed by photoemission spectroscopy

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    In this study, we report on investigations of the electronic structure of SrTiO3_3 annealed at temperature ranging between 550 and 840^\circC in an ultrahigh vacuum. Annealing induced oxygen vacancies (Ovac_{vac}) impart considerable changes in the electronic structure of SrTiO3_3. Using core-level photoemission spectroscopy, we have studied the chemical potential shift (Δμ\Delta\mu) as a function of annealing temperature. The result shows that the chemical potential monotonously increases with electron doping in SrTiO3δ_{3-\delta}. The monotonous increase of the chemical potential rules out the existence of electronic phase separation in the sample. Using valence band photoemission, we have demonstrated the formation of a low density of states at the near Fermi level electronic spectrum of SrTiO3δ_{3-\delta}. The gap-states were observed by spectral weight transfer over a large energy scale of the stoichiometric band gap of SrTiO3_3 system leading finally to an insulator - metal transition. We have interpreted our results from the point of structural distortions induced by oxygen vacancies.Comment: 7 pages, 6 figures, 1 tabl

    Micro-irrigation in Indian Agriculture-progress, impact and estimation of indicative cost

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    70-78Agriculture sector is the largest consumer of total water resources available in India. In view of increasing demand from all sectors of economy, declining availability and changing climate necessitates to bring down the use of water in agriculture below 50 percent from its present level. Hence, it is being emphasized to adopt innovative agricultural technologies (micro-irrigation methods), crops/cropping system requiring low water and development of drought tolerant varieties. In present scenario, the micro-irrigation methods are being seen as an alternative for increasing water use efficiency in agriculture. This article describes significance of micro irrigation, progress made, farm level impacts, and estimate of indicative cost to be required for the adoption of potential area to be brought under this technology
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