A novel bacteriohopanoid from Celtis australis L.bark

A novel bacteriohopanoid elucidated as 3β-hydroxy-35-(cyclohexyl-5’-propan-7’-one)-33-ethyl-34-methyl-bactereohopane(1) has been isolated from the bark of Celtis australis(Ulmaceae) together with three known compounds apigenin,quercetin and its glucoside.The structure of 1 was characterized by means of chemical and spectral methods including advanced 2D NMR studies.     

Wedge plate interferometry: a new dual field configuration for collimation testing

A method of deriving a dual field fringe pattern from a single wedge plate for collimation testing is presented. The proposed technique uses a wedge plate and a 90° prism retroreflector to form two interference fields. With the two sets of fringes, the technique provides twofold increase in sensitivity and has its own reference.     

Trace characterisation of lithium niobate by neutron activation analysis

Summary Coprecipitation behaviour of As, Au, Co, Cr, Cu, Eu, Fe, Ir, La, Lu, Mn, Mo, Nb, Ni, Pd, Pt, Sb, Sc, Ta, W, Zn and Zr during precipitation of hydrous oxide of niobium from lithium niobate was investigated. The matrix was dissolved in HF-HNO₃, evaporated to dryness and niobium was precipitated from HNO₃-H₂O₂ medium. The recovery studies were made using radiotracers. A radiochemical separation scheme based on group precipitation has been developed for the determination of Au, Co, Cr, Cu, Fe, Mn, Ni, Pd, Pt, Zn, Zr and rare earth elements. The method was applied to the analysis of lithium niobate. This analysis has provided fruitful information for improving the quality of the crystal.     

Magnetic and structural properties of CaO–SiO2–P2O5–Na2O–Fe2O3 glass ceramics

Magnetic properties of glass ceramics derived from glasses with composition 41CaO·(52−x)SiO₂·4P₂O₅·xFe₂O₃·3Na₂O (2?x?10 mol% iron oxide (Fe₂O₃)) are reported. Structural investigation revealed the presence of nanocrystalline magnetite phase in the heat-treated samples containing x?2 mol% Fe₂O₃. Magnetic hysteresis cycles of the glass-ceramic samples were obtained with a maximum applied field of ±20 kOe as well as a low field of ±500 Oe, in order to evaluate the potential of these glass ceramics for hyperthermia treatment of cancer. Samples with x>2 mol% of iron oxide exhibited magnetic behavior similar to soft magnetic materials with low coercivity. The evolution of magnetic properties in these samples as a function of iron oxide molar concentration is correlated with the amount and crystallite size of magnetite phase present in them.     

Evaluation of spectral phase in spectrally resolved white-light interferometry: Comparative study of single-frame techniques

Spectral phase in a white-light interferogram contains information about the absolute optical path difference (OPD) in the interferometer. Evaluation of spectral phase is therefore important in applications such as profilometry with white light. In spectrally resolved white-light interferometry (SRWLI) the white-light interferogram is spectrally decomposed by a spectrometer in order to determine this phase. Several single-frame techniques in SRWLI have been proposed for the evaluation of the phase including Fourier transform, Hilbert transform, spatial phase shifting, windowed Fourier transform and wavelet transform. In this paper we present a comparative study of these techniques in this application in relation to the temporal phase-shifting technique which is a multi- frame method. Further, we also propose a modified method to remove the influence of source spectrum modulation in Hilbert transform procedure.     

Some studies on the phase formation and kinetics in TiO<Subscript>2</Subscript> containing lithium aluminum silicate glasses nucleated by P<Subscript>2</Subscript>O<Subscript>5</Subscript>

Lithium aluminum silicate (LAS) glasses of compositions (wt%) 10.6Li₂O–71.7SiO₂–7.1Al₂O₃–4.9K₂O–3.2B₂O₃–1.25P₂O₅–1.25TiO₂ were prepared by the melt quench technique. Crystallization kinetics was investigated by the method of Kissinger and Augis–Bennett using differential thermal analysis (DTA). Based on the DTA data, glass ceramics were prepared by single-, two-, and three-step heat treatment schedules. The interdependence of different phases formed, microstructure, thermal expansion coefficient (TEC) and microhardness (MH) was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermo-mechanical analysis (TMA), and microhardness (MH) measurements. Crystallization kinetics revealed that Li₂SiO₃ is the kinetically favored phase with activation energy of 91.10 kJ/mol. An Avrami exponent of n = 3.33 indicated the dominance of bulk crystallization. Based upon the formation of phases, it was observed that the two-stage heat treatment results in highest TEC glass ceramics. The single-step heat treatment yielded glass ceramics with the highest MH.     

Facile and efficient preparation of hybrid phenylthiazolyl-1,3,5-triazines and their antidepressant-like effect in mice

High safety, robust efficacy, and rapid onset of action remain the key challenges for improving antidepressant drug discovery. We report a facile and efficient synthetic strategy to structurally encompass mono-, di-, or tri-substituted derivatives using cyanuric chloride and various substituted phenylthiazole-2-amines. The predicted physicochemical property precisely state their specificity as CNS acting agent and antidepressant-like effect of the most promising compound 10 after oral administration significantly reduced immobility in mice behavior models, especially TST from 63 s. In addition, good safety features of 10 highlight its ability to modulate hallmarks for antidepressant discovery. These insights are useful in generalization and systematization of CRF₁ antagonist design to develop future biological end points.     

Sintering kinetic study of the nano-crystalline 3-mol% yttria-samaria codoped tetragonal zirconia polycrystal ceramics

Dilatometric shrinkage data was utilized to study the sintering kinetics of the in-house synthesized nano-crystalline 3-mol% yttria-samaria codoped tetragonal zirconia polycrystal (TZP) ceramics. The objective was to determine activation energy (Q) of sintering and the sintering mechanism (n) relevant to the initial stage of sintering. The product of activation energy and sintering parameter, i.e., “nQ” was calculated from the shrinkage data acquired from the constant rate of heating experiment. The apparent activation energy of sintering (Q) was calculated using modified-“Dorn” method. Modified Johnson’s equation was used to determine value of “n” using the activation energy obtained from the Dorn method. Stepwise isothermal dilatometry technique was utilized as an independent method to determine the “n” value. The activation energy of sintering was in the range of 400–525 kJ mol^?1 and found to be dependent on the dopant concentration. The value of “n” was found to be ~0.33 for both 3 mol% yttria-doped (3Y-TZP) and yttria-samaria codoped (3(Y,S)-TZP) TZP, whereas for 3 mol% samaria-doped tetragonal zirconia (3S-TZP), the value of “n” was ~0.40. From the obtained “n” values, it may be concluded that grain boundary diffusion (GBD) was the dominant sintering mechanism in 3Y-TZP and 3(Y,S)-TZP, whereas an intermediate of GBD and volume diffusion influences the initial sintering stage in the 3S-TZP.     

A comparative study of phase-shifting algorithms in digital speckle pattern interferometry

Digital speckle pattern interferometry (DSPI) is a tool for making qualitative as well as quantitative measurements of deformation of objects. Phase-shifting algorithms in DSPI are useful for extracting quantitative deformation data from the system. Comparative studies of the different phase-shifting algorithms in DSPI for object deformation measurement are presented. Static and quasi-dynamic deformation of the object can be measured using these algorithms. Error compensating five-step phase-shifting method is used for the algorithms.     

Curvature measurement using three-aperture digital shearography and fast Fourier transform

Curvature measurement using a three-aperture digital shearography (DS) system is reported in this paper. The outer apertures are covered with wedge plates for introducing shear. Four images by sequentially blocking the outer apertures are used for quantitative measurement. Fourier transform technique is used to determine two sheared slope phase maps from two images at a time representing initial and deformed states. Subtraction of these two-phase maps yields the curvature phase map. Experimental results are presented for a circular diaphragm clamped along the edges and loaded at the center.