LRS Bianchi Type-I Dark Energy Cosmological Model in Brans-Dicke Theory of Gravitation

Bianchi type-I dark energy model with variable equation of state (EoS) parameter is presented in a scalar-tensor theory of gravitation proposed by Brans and Dicke (Phys. Rev. 124:925, 1961). To get a determinate solution of the field equations we will take the help of special law of variation for Hubble’s parameter presented by Bermann (Nuovo Cimento B. 74:182, 1983) which yields a dark energy cosmological model with negative constant deceleration parameter. It is observed that this dark energy cosmological model always represents an accelerated and expanding universe and also consistent with the recent observations of type-Ia supernovae. Some physical and geometrical properties of the model are also discussed.     

Near-edge X-ray absorption fine structure spectroscopy and structural properties of Ni-doped CeO2 nanoparticles

Ni-doped CeO₂ nanoparticles were prepared by using the co-precipitation method. The prepared nanoparticles were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The XRD results infer that Ni-doped CeO₂ nanoparticles have single phase nature similar to that of pure CeO₂ nanoparticles. We have calculated lattice parameters using Powder-X software, particle size using Scherer’s formula and strain using the Williamson-Hall method for all the synthesized samples. We have observed a systematic decrease in the lattice parameters, particle size and strain with an increase in Ni doping in CeO₂. The FE-SEM micrographs also confirm that Ni-doped CeO₂ have nanocrystalline behavior and particles are spherical shaped. From the Raman spectra, it is observed that the intensity of classical CeO₂ vibration modes first increases then decreases with Ni doping. The NEXAFS spectra measured at Ce M_4,5 and Ni L_3,2 edges clearly indicate that Ce ions are in the +4 valence state and Ni ions are in the +2 valence state.     

Synthesis of aminouracil-tethered tri-substituted methanes in water by iodine-catalyzed multicomponent reactions

Molecular Diversity - An efficient, mild and environmentally benign protocol has been developed for the synthesis of aminouracil-tethered tri-substituted methane derivatives. The three-component...     

Technical evaluation of in vivo abdominal fat and IMCL quantification using MRI and MRSI at 3 T

OBJECTIVES: The objectives of this study were to develop protocols that measure abdominal fat and calf muscle lipids with magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS), respectively, at 3 T and to examine the correlation between these parameters and insulin sensitivity. MATERIALS AND METHODS: Ten nondiabetic subjects [five insulin-sensitive (IS) subjects and five insulin-resistant (IR) subjects] were scanned at 3 T. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were segmented semiautomatically from abdominal imaging. Intramyocellular lipids (IMCL) in calf muscles were quantified with single-voxel MRS in both soleus and tibialis anterior muscles and with magnetic resonance spectroscopic imaging (MRSI). RESULTS: The average coefficient of variation (CV) of VAT/(VAT+SAT) was 5.2%. The interoperator CV was 1.1% and 5.3% for SAT and VAT estimates, respectively. The CV of IMCL was 13.7% in soleus, 11.9% in tibialis anterior and 2.9% with MRSI. IMCL based on MRSI (3.8+/-1.2%) were significantly inversely correlated with glucose disposal rate, as measured by a hyperinsulinemic-euglycemic clamp. VAT volume correlated significantly with IMCL. IMCL based on MRSI for IR subjects was significantly greater than that for IS subjects (4.5+/-0.9% vs. 2.8+/-0.5%, P=.02). CONCLUSION: MRI and MRS techniques provide a robust noninvasive measurement of abdominal fat and muscle IMCL, which are correlated with insulin action in humans.     

Regioselective synthesis of pyrimidine-fused tetrahydropyridines and pyridines by microwave-assisted one-pot reaction

Molecular Diversity - A regioselective three-component reaction of α,β-unsaturated aldehydes, cyclic 1,3-dicarbonyls and 6-aminouracils in the presence of FeCl3·6H2O as catalyst...     

Formulation and radiochemical evaluation of a freeze-dried mixed peptide kit for the preparation of 68Ga-labeled peptides for PET imaging of somatostatin receptor positive neuroendocrine cancers

⁶⁸Ga-labeled DOTA-coupled somatostatin analogue peptides are regularly being used for the PET imaging of patients suspected to be suffering from various types of neuroendocrine cancers over-expressing somatostatin receptors. The article describes the formulation of a freeze-dried mixed peptide kit containing equal amounts of DOTA-TATE and DOTA-NOC and the radiochemical evaluation of the kit for the easy and convenient preparation of ⁶⁸Ga-labeled mixed radiopeptides. The simultaneous use of two different peptides in the kit is expected to perceive more cancerous lesions and may have a wider applicability in the diagnosis of neuroendocrine cancers.     

Thermal Expansion,Anharmonicity and Temperature‐Dependent Raman Spectra of Single‐ and Few‐Layer MoSe2 and WSe2

We report the temperature‐dependent Raman spectra of single‐ and few‐layer MoSe₂ and WSe₂ in the range 77–700 K. We observed linear variation in the peak positions and widths of the bands arising from contributions of anharmonicity and thermal expansion. After characterization using atomic force microscopy and high‐resolution transmission electron microscopy, the temperature coefficients of the Raman modes were determined. Interestingly, the temperature coefficient of the A²_2u mode is larger than that of the A_1g mode, the latter being much smaller than the corresponding temperature coefficients of the same mode in single‐layer MoS₂ and of the G band of graphene. The temperature coefficients of the two modes in single‐layer MoSe₂ are larger than those of the same modes in single‐layer WSe₂. We have estimated thermal expansion coefficients and temperature dependence of the vibrational frequencies of MoS₂ and MoSe₂ within a quasi‐harmonic approximation, with inputs from first‐principles calculations based on density functional theory. We show that the contrasting temperature dependence of the Raman‐active mode A_1g in MoS₂ and MoSe₂ arises essentially from the difference in their strain–phonon coupling.     

Triple domino reaction for the synthesis of pyrazole/indoline linked chromenes

A simple and convenient method towards the synthesis of highly diversified chromenopyrazole/indoline frameworks in excellent yields via iodine promoted triple domino reaction involving Michael addition followed by intramolecular cyclization and dehydrogenation sequence has been described for the first time.