Classification of Plane Symmetric Static Space-Times According to Their Noether Symmetries

In this paper we give a classification of plane symmetric static space-times using symmetry method. For this purpose we consider the Lagrangian corresponding to the general plane symmetric static metric in the Noether symmetry equation. This provides a system of determining equations. Solutions of this system give us classification of the plane symmetric static space-times according to their Noether symmetries. During this classification we recover all the results listed in Feroze et al. (J. Math. Phys. 42:4947, 2001) and Bashir and Ehsan (Il Nuovo Cimento B 123:1, 2008).     

Synthesis and structure determination of 7a-Aza-B-homostigmast-5-eno [7a, 7-d] tetrazole-3β-yl chloride (C29H47N4Cl)

7a-Aza-B-homostigmast-5-eno [7a, 7-d] tetrazole-3β-yl chloride (C₂₉H₄₇N₄Cl) was synthesized for its crystallographic analysis and to investigate the role of intra- and intermolecular interactions in steroids. It crystallizes in the monoclinic space group C2 with unit cell parameters: a = 38.481(2), b = 6.661(3), c = 11.111 (6) ?, β = 94.49 (4)^o; λ( MoKα) = 0.71069 ?, V = 2839(2) ?³, and Z = 4. The structure has been solved by direct methods using X-ray diffraction techniques. The final reliability index for the computed structure is 0.0597 for 1252 observed reflections. Except the five-membered ring, all other rings of the steroid nucleus exist in non-planar conformations. The structure is stabilized by C–H···N intermolecular interaction.Supplementary material CCDC-267926 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge at www.ccdc.cam.an.uk/uk/conts/retrieving.html or from the Cambridge Crystallographic Data Centre (CCDC), 12 Union Road, Cambridge CB2 1EZ, United Kingdom; Fax: $+$44(0) 1223-336033; e-mail: deposit@ccdc.cam.ac.uk.     

Development of green sodium sulfate‐induced solidification of floating organic droplets–dispersive liquid phase microextraction method: Application to extraction of four antidepressants

Sodium sulfate‐induced deep eutectic solvent–based solidification of floating organic droplets–dispersive liquid phase microextraction was developed prior to gas chromatography–mass spectrometry. In this method, a mixture of Na₂SO₄ solution (as phase separation agent and disperser) containing menthol–decanoic acid was rapidly injected into an alkaline aqueous solution containing Na₂SO₄. The solution was placed in an ice bath and the menthol–decanoic acid solvent was solidified on the surface of the solution. Under the optimal conditions, the enrichment factors and extraction recoveries were 122–147 and 74–89%, respectively. Finally, an aliquot of the collected organic phase was removed and mixed with acetonitrile and injected into the separation system. The limits of detection and lower limits of quantification were obtained at the ranges of 13–25 and 24–41 ng L^?1, respectively. The relative standard deviations of the proposed method were ≤11% for intra‐ and inter‐day precisions at four concentrations.     

One‐Pot Synthesis of 6,7‐Fused Steroidal Thiazoles in Cholestane Series

A convenient one‐pot synthesis of 2′‐amino‐ and 2′‐N‐phenylamino‐5α‐cholest‐6‐eno[6,7‐d]thiazole derivatives 4 ‐ 9 are reported. The synthesis involves the reaction of cholestan‐6‐ones 1 ‐ 3 with thiourea or phenylthiourea and iodine. The products have been characterized on the basis of IR, ¹H‐NMR and Mass, which find support in two cases from comparison with authentic samples.     

Derivatives of substituted 3‐trichlorogermylpropionic acid

The central Ge atoms in the structures of 3‐(2‐fluoro­phenyl)‐3‐(tri­phenyl­germyl)­propionic acid, [Ge(C₆H₅)₃(C₉H₈FO₂)], 3‐(2‐tolyl)‐3‐(tri‐4‐tolyl­germyl)­propionic acid, [Ge(C₇H₇)₃(C₁₀H₁₁O₂)], and 3‐(4‐tolyl)‐3‐(tri­benzyl­germyl)­propionic acid, [Ge(C₇H₇)₃(C₁₀H₁₁O₂)], are four‐coordinate with slightly distorted tetrahedral geometry. The Ge—Csp³ distances [1.970 (3)–1.997 (3) Å] are significantly longer than the Ge—C_aromatic distances [1.940 (3)–1.959 (2) Å]. In all three structures, the mol­ecules form dimeric pairs about inversion centres through strong hydrogen‐bonding interactions between carboxyl­ic acid groups.     

Internal Anatomy of Common Carp (Cyprinus carpio) as Revealed by Magnetic Resonance Imaging

Slices of T2-weighted and fat-suppressed images were obtained on a clinical scanner with the field strength of 1 T to identify various tissues, internal organs and structural details of a cyprinid fish (Cyprinus carpio). Different parts of pharyngeal and gastro-intestinal organs, liver and spleen were well distinguished. Kidneys were traced and the position of heart and its appendants such as bulbus arteriosus, ventral aorta and branchial arteries were identified. The images were confirmed by the corresponding slices of frozen fish.     

Quantum carpets: efficiently probing fractional revivals in position-dependent mass systems

Position-dependent-mass systems are of great importance in many physical situations,such as the transport of charge carriers in semiconductors with non-uniform composition and in the theory of many-body interactions in condensed matter.Here we investigate,numerically and analytically,the phenomenon of fractional revivals in such systems,which is a generic characteristic manifested by the wave-packet evolution in bounded Hamiltonian systems.Identifying the fractional revivals using specific probe...     

The synthesis of 2′-amino-5α-cholest-6-eno [6,7-d]-thiazole derivatives under microwave irradiation using dry-media conditions

A convenient,rapid and efficient method for the synthesis of substituted steroidal[6,7-d]thiazoles using microwave-induced organic reaction enhancement chemistry has been developed.The additional features of this methodology include a much faster reaction,easy workup,high yield,high purity of the products and an environment friendly approach.