Stroke Prediction from Hypertensive Retinopathy

Hypertensive Retinopathy (HR) is known as the damage to the eye which occurs due to high blood pressure. This HR may lead to permanent vision lost hence timely diagnosis and treatment of this disease is very important. Fundus image analysis is used to diagnose HR and stroke prediction. There are four steps in the proposed systems which are the Image Enhancement, Fourier Fractal Dimension, Logistic Regression Classifier and Stroke Prediction Model. The proposed system consists of method used to analyse retina blood vessels using Fourier Fractal Dimension to extract the complexity of the retina blood vessels enhanced in different scales. Logistic regression was used to model the classifier for stroke prediction. The probability from 0 to 0.5 was classified as control case and the probability from 0.5 to 1 was classified as stroke case. From 20 images used in this project only 14 images was classified as the stroke case. The estimated percentage increase in the odds of incident of stroke is calculated and categorised according to the Hypertensive Retinopathy stages

Some Experiences in Electro-winning of Aluminium from Fused Chloride Bath

Although the electro-winning of aluminium from out of a fused chloride bath dates back to 1854, When Bunsen first isolated the metal, the interest in the process since then has been sporadic. Earlier work in this labo-ratory had not'only confirmed the results reported in the-literature, but had gone a step ahead in proposing and conducting electrolysis on extended time schedule with periodic additions of the trichloride. This work however was conducted at an optimum temperature of 400°C i.e. below the melting point-of the metal which was obtained mostly as loosely adherent flakes. The recovery of such a deposit had been problematical and the cell operation had to interrupted because the fluffy deposit would soon accumulate to short circuit the electrodes. Further it would drop off the c athode while the same was being removed, thus further complicating the procedure

Antiferromagnetic vs ferromagnetic interactions and spin-glass-like behavior in ruthenates

We have made a series of gradient-corrected relativistic full-potential density-functional calculation for Ca-substituted and hole-doped SrRuO$_3$ in para, ferro, and $A$-, $C$-, and $G$-type antiferromagnetic states. Magnetic phase-diagram data for Sr$_{1-x}$Ca$_x$RuO$_3$ at 0 K are presented. Neutron diffraction measurement combined with total energy calculations show that spin-glass behavior with short-range antiferromagnetic interactions rules in CaRuO$_3$. The substitution of Sr by Ca in SrRuO$_3$ decreases the ferromagnetic interaction and enhances the $G$-type antiferromagnetic interaction; the $G$-AF state is found to stabilize around $x$ = 0.75 consistent with experimental observations. Inclusion of spin-orbit coupling is found to be important in order to arrive at the correct magnetic ground state in ruthenates.Comment: 5 pages, 3 figures. Solid state communications (in press

Pressure-induced structural transitions in MgH2{_2}

The stability of MgH$_2$ has been studied up to 20~GPa using density-functional total-energy calculations. At ambient pressure $\alpha$-MgH${_2}$ takes a TiO$_2$-rutile-type structure. $\alpha$-MgH$_2$ is predicted to transform into $\gamma$-MgH${_2}$ at 0.39~GPa. The calculated structural data for $\alpha$- and $\gamma$-MgH${_2}$ are in very good agreement with experimental values. At equilibrium the energy difference between these modifications is very small, and as a result both phases coexist in a certain volume and pressure field. Above 3.84~GPa $\gamma$-MgH${_2}$ transforms into $\beta$-MgH${_2}$; consistent with experimental findings. Two further transformations have been identified at still higher pressure: i) $\beta$- to $\delta$-MgH${_2}$ at 6.73 GPa and (ii) $\delta$- to $\epsilon$-MgH${_2}$ at 10.26~GPa.Comment: 4 pages, 4 figure

Some experiences in Electro-winning of Aluminium from fused Chloride bath

ALTHOUGH the electro-winning of aluminium from a fused chloride bath dates back to 1854, when Bunsen first isolated the metal, the interest in the process since then has been sporadic. Some of the earlier documenters like Mellor', Richards2, Borches3 and others had taken up the lead, but had been discouraged into branding the approach as impracticable. Patents filed by Aluminium Industrie A.G.4, I.G. Farben Industrie, A.G.5, Henriques and Thomsen6, Brode7, Treadwell8, Daudonnet9 and others during the period 1928 to 1931 indicated a resurgence of the chloride bath, although in the subsequent period the only mentionable patents were by Lovel and Phillips in 194510, Electronic Reduction Corporation in 1951,11 Grothe12 in 1953, and by Slatin13 in 1959 and 1963. Some of these were for the declared purpose of electroplating rather than electro-winning. The published investigations are also equally sporadic, and mention may be made of the work of Fink and Solanki14, Ramachandran15, and Newalkar and Altekar16

Detailed electronic structure studies on superconducting MgB2_2 and related compounds

In order to understand the unexpected superconducting behavior of MgB$_2$ compound we have made electronic structure calculations for MgB$_2$ and closely related systems. Our calculated Debye temperature from the elastic properties indicate that the average phonon frequency is very large in MgB$_2$ compared with other superconducting intermetallics and the exceptionally high $T_c$ in this material can be explained through BCS mechanism only if phonon softening occurs or the phonon modes are highly anisotropic. We identified a doubly-degenerate quasi-two dimensional key-energy band in the vicinity of $E_{F}$ along $\Gamma$-A direction of BZ which play an important role in deciding the superconducting behavior of this material. Based on this result, we have searched for similar kinds of electronic feature in a series of isoelectronic compounds such as BeB$_2$, CaB$_2$, SrB$_2$, LiBC and MgB$_2$C$_2$ and found that MgB$_2$C$_2$ is one potential material from the superconductivity point of view. There are contradictory experimental results regarding the anisotropy in the elastic properties of MgB$_2$ ranging from isotropic, moderately anisotropic to highly anisotropic. In order to settle this issue we have calculated the single crystal elastic constants for MgB$_2$ by the accurate full-potential method and derived the directional dependent linear compressibility, Young's modulus, shear modulus and relevant elastic properties. We have observed large anisotropy in the elastic properties. Our calculated polarized optical dielectric tensor shows highly anisotropic behavior even though it possesses isotropic transport property. MgB$_2$ possesses a mixed bonding character and this has been verified from density of states, charge density and crystal orbital Hamiltonian population analyses

Stroke Prediction from Hypertensive Retinopathy

Hypertensive Retinopathy (HR) is known as the damage to the eye which occurs due to high blood pressure. This HR may lead to permanent vision lost hence timely diagnosis and treatment of this disease is very important. Fundus image analysis is used to diagnose HR and stroke prediction. There are four steps in the proposed systems which are the Image Enhancement, Fourier Fractal Dimension, Logistic Regression Classifier and Stroke Prediction Model. The proposed system consists of method used to analyse retina blood vessels using Fourier Fractal Dimension to extract the complexity of the retina blood vessels enhanced in different scales. Logistic regression was used to model the classifier for stroke prediction. The probability from 0 to 0.5 was classified as control case and the probability from 0.5 to 1 was classified as stroke case. From 20 images used in this project only 14 images was classified as the stroke case. The estimated percentage increase in the odds of incident of stroke is calculated and categorised according to the Hypertensive Retinopathy stages

Electronic structure, phase stability and chemical bonding in Th2_2Al and Th2_2AlH4_4

We present the results of theoretical investigation on the electronic structure, bonding nature and ground state properties of Th$_2$Al and Th$_2$AlH$_4$ using generalized-gradient-corrected first-principles full-potential density-functional calculations. Th$_2$AlH$_4$ has been reported to violate the "2 \AA rule" of H-H separation in hydrides. From our total energy as well as force-minimization calculations, we found a shortest H-H separation of 1.95 {\AA} in accordance with recent high resolution powder neutron diffraction experiments. When the Th$_2$Al matrix is hydrogenated, the volume expansion is highly anisotropic, which is quite opposite to other hydrides having the same crystal structure. The bonding nature of these materials are analyzed from the density of states, crystal-orbital Hamiltonian population and valence-charge-density analyses. Our calculation predicts different nature of bonding for the H atoms along $a$ and $c$. The strongest bonding in Th$_2$AlH$_4$ is between Th and H along $c$ which form dumb-bell shaped H-Th-H subunits. Due to this strong covalent interaction there is very small amount of electrons present between H atoms along $c$ which makes repulsive interaction between the H atoms smaller and this is the precise reason why the 2 {\AA} rule is violated. The large difference in the interatomic distances between the interstitial region where one can accommodate H in the $ac$ and $ab$ planes along with the strong covalent interaction between Th and H are the main reasons for highly anisotropic volume expansion on hydrogenation of Th$_2$Al.Comment: 14 pages, 9 figure