Structural and physical properties of SrMn1−xRuxO3SrMn_{1-x}Ru_xO_3 perovskites

We combine the results of magnetic and transport measurements with neutron diffraction data to construct the structural and magnetic phase diagram of the entire family of SrMn$_{1-x}$Ru$_{x}$O$_3$ ($0 \leqslant x \leqslant 1$) perovskites. We have found antiferromagnetic ordering of the C type for lightly Ru-substituted materials ($0.06 \leqslant x \leqslant 0.5$) in a similar manner to $R_{y}$Sr$_{1-y}$MnO$_3$ ($R$=La, Pr), due to the generation of Mn$^{3+}$ in both families of manganite perovskites by either $B$-site substitution of Ru$^{5+}$ for Mn$^{4+}$ or $A$-site substitution of $R^{3+}$ for Sr$^{2+}$. This similarity is driven by the same ratio of $d^4$ / $d^3$ ions in both classes of materials for equivalent substitution level. In both cases, a tetragonal lattice distortion is observed, which for some compositions ($0.06 \leqslant x \leqslant 0.2$) is coupled to a C-type AF transition and results in a first order magnetic and resistive transition. Heavily substituted SrMn$_{1-x}$Ru$_{x}$O$_3$ materials are ferromagnetic due to dominating exchange interactions between the Ru$^{4+}$ ions. Intermediate substitution ($0.6 \leqslant x \leqslant 0.7$) leads to a spin-glass behavior instead of a quantum critical point reported previously in single crystals, due to enhanced disorder.Comment: 9 pages, 10 figures, accepted for publication in Physical Review

IDENTIFICATION OF BIOACTIVE COMPOUNDS IN CYMODOCEA SERRULATA-A SEAGRASS BY GAS CHROMATOGRAPHY–MASS SPECTROSCOPY

Objective: The objective of this study was to identify the lead phytocompounds present in the ethanol extract of the seagrass Cymodocea serrulata by gas chromatography–mass spectrometry (GCMS).Methods: 1 kg of C. serrulata whole seagrass powder was subjected to extraction on polarity basis using five solvent such as hexane, chloroform, ethyl acetate, ethanol, and water. Since ethanol extract showed a maximum antioxidant property, its phytochemicals were investigated using GCMS technique. The phytocompounds identified through GC were interpreted with mass spectra national institute standard and technology library.Result: The GCMS analysis of ethanol extract of C. serrulata identified peaks of six different compounds they are hexahydrofarnesyl acetone (7.70%), hexadecanoic acid, methyl ester (4.11%), tetradecanoic acid (62.89%), pentadecanoic acid(62.89%), cholesta4, 6dien3ol (5.88%), and stigmasterol (19.42%).Conclusion: The GCMS study of C. serrulata ethanol extract unveils the presence of bioactive compounds that have a pharmacological and nutraceutical values

Rhodium Doped Manganites : Ferromagnetism and Metallicity

The possibility to induce ferromagnetism and insulator to metal transitions in small A site cation manganites Ln_{1-x}Ca_xMnO_3 by rhodium doping is shown for the first time. Colossal magnetoresistance (CMR) properties are evidenced for a large compositional range (0.35 \leq x < 0.60). The ability of rhodium to induce such properties is compared to the results obtained by chromium and ruthenium doping. Models are proposed to explain this behavior.Comment: 11 pages, 8 figure

Phytochemical screening and in vitro antioxidant activity of the seagrass Cymodocea serrulata

1216-1221The seagrass Cymodocea serrulata was collected from Ramanathapuram coastal region and its antioxidant potential was determined. The ethanol extract showed the highest phenolic content of 284.94 mg/ml gallic acid equivalence and the ethyl acetate extract showed the highest flavonoids content of 40.18 mg/ml quercetin equivalence. The tannin content was higher at 264.71 mg/ml tannic acid equivalence in aqueous extract. The ethanol extract exhibited the highest 2,2 diphenyl-1-picrylhydrazyl (DPPH) and 2,2¢-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity with IC50 values of 44.47 µg and 2.5 µg, respectively. The ferric reducing ability and nitric oxide scavenging activity were efficient in both ethanol and aqueous extracts. The superoxide scavenging activity was high in hexane extract. The comparative antioxidant study of the subsequent extract of C. serrulata showed that the ethanol extract possesses the highest free radical scavenging property compared to other extracts. This may be due to the presence of high phenolic compounds. The study brings out the medicinal value of C. serrulata which can be used as a nutraceutical compound in various food and pharmaceutical industries

Electronic phase separation in the rare earth manganates, (La1-xLnx)0.7Ca0.3MnO3 (Ln = Nd, Gd and Y)

All the three series of manganates showsaturation magnetization characteristic of ferromagnetism, with the ferromagnetic Tc decreasing with increasing in x up to a critical value of x, xc (xc = 0.6, 0.3, 0.2 respectively for Nd, Gd, Y). For x > xc, the magnetic moments are considerably smaller showing a small increase around TM, the value of TM decreasing slightly with increase in x or decrease in . The ferromagnetic compositions (x xc) show insulator-metal (IM) transitions, while the compositions with x > xc are insulating. The magnetic and electrical resistivity behavior of these manganates is consistent with the occurrence of phase separation in the compositions around xc, corresponding to a critical average radius of the A-site cation, , of 1.18 A. Both Tc and TIM increase linearly when < rA > > or x xc as expected of a homogenous ferromagnetic phase. Both Tc and TM decrease linearly with the A-site cation size disorder at the A-site as measured by the variance s2. Thus, an increase in s2 favors the insulating AFM state. Percolative conduction is observed in the compositions with > < rAc >. Electron transport properties in the insulating regime for x > xc conforms to the variable range hopping mechanism. More interestingly, when x > xc, the real part of dielectric constant (e') reaches a high value (104-106) at ordinary temperatures dropping to a very small (~500) value below a certain temperature, the value of which decreases with decreasing frequency.Comment: 27 pages; 11 figures, Submitted to J.Phys:Condens Matte

Monitoring vegetation dynamics using multi-temporal Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) images of Tamil Nadu

Vegetation indices serve as an essential tool in monitoring variations in vegetation. The vegetation indices used often, viz., normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) were computed from MODIS vegetation index products. The present study aimed to monitor vegetation's seasonal dynamics by using time series NDVI and EVI indices in Tamil Nadu from 2011 to 2021. Two products characterize the global range of vegetation states and processes more effectively. The data sources were processed and the values of NDVI and EVI were extracted using ArcGIS software. There was a significant difference in vegetation intensity and status of vegetation over time, with NDVI having a larger value than EVI, indicating that biomass intensity varies over time in Tamil Nadu. Among the land cover classes, the deciduous forest showed the highest mean values for NDVI (0.83) and EVI (0.38), followed by cropland mean values of NDVI (0.71) and EVI (0.31) and the lowest NDVI (0.68) and EVI (0.29) was recorded in the scrubland. The study demonstrated that vegetation indices extracted from MODIS offered valuable information on vegetation status and condition at a short temporal time period

Crystal structures and magnetic order of La{0.5+delta}A{0.5-delta}Mn{0.5+epsilon}Ru{0.5-epsilon}O{3} (A= Ca, Sr, Ba): Possible orbital glass ferromagnetic state

The crystallographic and magnetic properties of La{0.5+delta}A{0.5-delta}Mn{0.5+epsilon}Ru{0.5-epsilon}O{3} (A= Ca, Sr, Ba) were investigated by means of neutron powder diffraction. All studied samples show the orthorhombic perovskite crystal structure, space group Pnma, with regular (Mn,Ru)O{6} octahedra and no chemical ordering of the Mn3+ and Ru4+ ions. Ferromagnetic spin structures were observed below Tc ~ 200-250 K, with an average ordered moment of ~ 1.8-2.0 Bohr magnetons per (Mn,Ru). The observation of long-range ferromagnetism and the absence of orbital ordering are rationalized in terms a strong Mn-Ru hybridization, which may freeze the orbital degree of freedom and broaden the eg valence band, leading to an orbital-glass state with carrier-mediated ferromagnetism

Variazioni sul tema della prigionia: La Captive di Chantal Akerman.

Properties of the hole-doped Ln1−xAxMnO3 (Ln=rare earth, A=alkaline earth, x&lt;0.5) are compared with those of the electron-doped compositions (x&gt;0.5). Charge ordering is the dominant interaction in the latter class of manganates unlike ferromagnetism and metallicity in the hole-doped materials. Properties of charge-ordered (CO) compositions in the hole- and electron-doped regimes, Pr0.64Ca0.36MnO3 and Pr0.36Ca0.64MnO3, differ markedly. Thus, the CO state in the hole-doped Pr0.64Ca0.36MnO3 is destroyed by magnetic fields and by substitution of Cr3+ or Ru4+ (3%) in the Mn site, while the CO state in the electron-doped Pr0.36Ca0.64MnO3 is essentially unaffected. It is not possible to induce long-range ferromagnetism in the electron-doped manganates by increasing the Mn-O-Mn angles up to 165 and 180° as in La0.33Ca0.33Sr0.34MnO3; application of magnetic fields and Cr/Ru substitution (3%) do not result in long-range ferromagnetism and metallicity. Application of magnetic fields on the Cr/Ru-doped, electron-doped manganates also fails to induce metallicity. These unusual features of the electron-doped manganates suggest that the electronic structure of these materials is likely to be entirely different from that of the hole-doped ones, as verified by first-principles linearized muffin-tin orbital calculations

Effect of growth regulators and micronutrients on quality parameters in cashew (Anacardium occidentale L.)

Cashew (Anacardium occidentale L.) is an important tropical nut crop of social and economic importance worldwide. However, the crop is threatened with the low yield. In the present study, an attempt was made to test the effects of plant growth hormones as well as micronutrients on nut and apple quality of cashew var. Bhaskara. Significant differences in kernel weight, shelling percentage, carbohydrates and starch content of cashew kernel and juice content of cashew apple were observed with the foliar application of growth hormones and micronutrients. The foliar application of ethrel @ 50 ppm increased shelling percentage (35.8%), carbohydrate content (21.63%), sugar content (6.26%), protein content (32.4%), starch content (31.42%), juice content (78.3%) and total soluble solids (120 Brix). Further, the foliar spray of zinc sulphate (0.5%) + borax (0.1%) increased shelling (36.13%), protein content (32.15%), starch content (32.03%) among all the treatments tested. Furthermore, higher cashew apple juice content (78%) and total soluble solids (120Brix) was also recorded with the foliar spray of zinc sulphate (0.5%) + borax (0.1%)

A function blocking anti-mouse integrin α5β1 antibody inhibits angiogenesis and impedes tumor growth in vivo

<p>Abstract</p> <p>Background</p> <p>Integrins are important adhesion molecules that regulate tumor and endothelial cell survival, proliferation and migration. The integrin α5β1 has been shown to play a critical role during angiogenesis. An inhibitor of this integrin, volociximab (M200), inhibits endothelial cell growth and movement <it>in vitro</it>, independent of the growth factor milieu, and inhibits tumor growth <it>in vivo </it>in the rabbit VX2 carcinoma model. Although volociximab has already been tested in open label, pilot phase II clinical trials in melanoma, pancreatic and renal cell cancer, evaluation of the mechanism of action of volociximab has been limited because this antibody does not cross-react with murine α5β1, precluding its use in standard mouse xenograft models.</p> <p>Methods</p> <p>We generated a panel of rat-anti-mouse α5β1 antibodies, with the intent of identifying an antibody that recapitulated the properties of volociximab. Hybridoma clones were screened for analogous function to volociximab, including specificity for α5β1 heterodimer and blocking of integrin binding to fibronectin. A subset of antibodies that met these criteria were further characterized for their capacities to bind to mouse endothelial cells, inhibit cell migration and block angiogenesis <it>in vitro</it>. One antibody that encompassed all of these attributes, 339.1, was selected from this panel and tested in xenograft models.</p> <p>Results</p> <p>A panel of antibodies was characterized for specificity and potency. The affinity of antibody 339.1 for mouse integrin α5β1 was determined to be 0.59 nM, as measured by BIAcore. This antibody does not significantly cross-react with human integrin, however 339.1 inhibits murine endothelial cell migration and tube formation and elicits cell death in these cells (EC₅₀= 5.3 nM). In multiple xenograft models, 339.1 inhibited the growth of established tumors by 40–60% (<it>p </it>< 0.05) and this inhibition correlates with a concomitant decrease in vessel density.</p> <p>Conclusion</p> <p>The results herein demonstrate that 339.1, like volociximab, exhibits potent anti-α5β1 activity and confirms that inhibition of integrin α5β1 impedes angiogenesis and slows tumor growth <it>in vivo</it>.</p