Performance characteristics of a Nd: glass laser amplifier from fluorescence emission studies

The dependence of cavity transfer efficiency of a Nd: glass laser amplifier on flashlamp current density is obtained from the analysis of amplified fluorescence. The cavity transfer efficiency decreases as the current density through the flashlamps is increased. The use of the fluorescence method in optimizing the flashlamp pulse duration for achieving maximum gain in the amplifier is illustrated.     

Hybrid Class Phenylthiazole and 1,2,3,4‐Tetrahydronaphthalene Target Sertraline Transporter for Antidepressant Action Revealed by Molecular Docking Studies

Phenylthiazolyl‐substituted 1,2,3,4‐tetrahydronaphthalene derivatives were synthesized, and their chemical structures were elucidated by Fourier transform infrared, ¹H‐NMR, ¹³C‐NMR spectral data and elemental analyses. Antidepressant‐like activities of these compounds were screened using both Porsolt's behavioural despair on albino mice and tail suspension tests. Open field test was also performed for the examination of probable neurological deficits, which may interfere with the test results. The test compounds exhibited different levels of antidepressant activities. Additionally, the key ligand was further substantiated by docking experiment to explore plausible mode of binding in molecular dynamics overflow. The studies elucidates role of a hydrophilic H‐bonding region and pi‐cation binding as a major driving force for biological activity.     

Aqueous spectroscopy and redox properties of carboxylate-bound titanium

The aqueous chemistry of Ti(III) and Ti(IV) in two different chemical environments is investigated given its relevance to environmental, materials, and biological chemistry. Complexes of titanium with the carboxylate ligands citrate and oxalate, found ubiquitously in Nature, were synthesized. The redox properties were studied by using cyclic voltammetry. All the titanium citrate redox couples are quasi-reversible. Electrospray mass spectrometry of the Ti(III) citrate solution shows the presence of a 1:2 Ti/cit complex in solution, in contrast to the predominant 1:3 Ti/cit complex with Ti(IV). The change in the coordination of the ligand to the metal on reduction may explain the quasi-reversible behavior of the electrochemistry. The redox potentials for Ti(IV) citrate in water vary with pH. At pH 7, the approximate E(1/2) is less than -800 mV. This stated change in redox properties is considered in light of the previously reported Ti(IV) citrate solution speciation. Analogous speciation behavior is suggested from the EPR spectroscopy of Ti(III) citrate aqueous solutions. The g tensors are deduced for several pH-dependent species from the simulated data. The X-ray crystal structure of a Ti(III)(2) oxalate dimer Ti(2)(mu-C(2)O(4))(C(2)O(4))(2)(H(2)O)(6).2H(2)O (3), which crystallizes from water below pH 2, is reported. Complex 3 crystallizes in a monoclinic P2(1)/c space group with a = 9.5088(19) Angstroms, b = 6.2382(12) Angstroms, c = 13.494(3) Angstroms, V = 797.8(3) Angstroms(3), and Z = 2. The infrared spectroscopy, EPR spectroscopy, and cyclic voltammetry on complex 3 are reported. The cyclic voltammetry shows an irreversible redox couple approximately -196 mV which likely corresponds to the Ti(IV)(2)/Ti(III)Ti(IV) couple. The EPR spectroscopy on solid complex 3 shows a typical S = 1 triplet-state spectrum. The solid follows non-Curie behavior, and the antiferromagnetic coupling between the two metal centers is determined to be -37.2 cm(-1). However, in solution the complex follows Curie behavior and supports a Ti(III)Ti(IV) oxidation state for the dimer.     

The nucleophilic addition of alpha-metallated 1,3-dioxanes to planar chiral cationic eta3-allylmolybdenum complexes. Synthesis of (2E,5S,6R,7E)-6-methyl-8-phenylocta-2,7-dienoic acid methyl ester, a key component of the Cryptophycins

Two adjacent stereogenic centres and a pendant alkene were constructed via nucleophilic addition of a 1,3-dioxan-4-ylcopper(I) reagent to a cationic eta3-allylmolybdenum complex as part of a synthesis of (2E,5S,6R,7E)-6-methyl-8-phenylocta-2,7-dienoic acid, a key component of the Cryptophycins. Oxidative addition of Mo(CO)(4)(THF)(2) to allyl benzoates provides an efficient synthesis of eta3-allylmolybdenum(dicarbonyl) complexes.     

Dichlorocarbene Addition to

In contrast to the terminal phosphinidene complex PhPW(CO)(5) (2), which adds to [5]metacyclophane (1) in a 1,4-fashion, dichlorocarbene preferentially adds in a 1,2-fashion to the formal "anti-Bredt" type double bond of the aromatic ring of 1 to afford the norcaradiene 11b, which immediately rearranges to the bridged cycloheptatriene 12b and further by a [1,5] sigmatropic chlorine migration to the isomeric 13b as the first observable product. More slowly, the latter isomerizes via a dissociative mechanism to give 15b. A computational study supports the notion that the [1,5] chlorine migration in the rearrangement 12b --> 13b, for which an activation barrier of 70.2 kJ mol(-)(1) was calculated, is essentially concerted with minor charge separation. In contrast, the analogous [1,5] chlorine migration in the flat model compound 7,7-dichlorocycloheptatriene (12a) displays features of a dissociative pathway.     

Visualization of fingerprints made easy with dye solution on cellulose membrane

正Fingerprinting has been used for over 100 years,especially for forensic investigations,personal identification,and law enforcement[1].Although reagent-based detection of fingerprints has been used since it was introduced in the 1880's,this technique has several shortcomings,such as the use of harmful reagents,laborious protocols,and the destruction of     

Design, synthesis and biological evaluation of choline based SPECT imaging agent: Ga(III)-DO3A-EA-Choline

The enhanced choline uptake and phosphorylation in tumor cells has motivated the development of radiolabeled choline derivatives as diagnostic markers for imaging cell membrane proliferation and noninvasive detection of prostate, brain and breast tumors. In the present work, we report a facile strategy for the synthesis of choline functionalized macrocyclic chelating agent (DO3A-EA-choline) and its radiocomplexation with (67)Ga for potential tumor imaging applications. The synthesis of the desired compound featured quaternization of N,N-dimethylaminoethanol with 1,2-dibromoethane followed by subsequent alkylation with trisubstituted cyclen (DO3A). All intermediates and final compounds have been fully characterized by spectroscopic techniques, namely, (1)H, (13)C NMR and mass spectroscopy. The compound has been successively labeled with (67)Ga-citrate in ammonium acetate buffer (pH 6.5) at 80 °C. MTT assays have been performed on the HEK cell line to determine the cytotoxicity of the compound. Cell uptake studies carried out on the U-87 MG cell line exhibited saturable binding of the radioconjugate in picomolar range with a K(d) value of 0.528 pM. The in vivo biodistribution and blood kinetics studies exhibited rapid clearance of the radiolabeled complex and excretion through the renal and hepatobiliary route. The present studies demonstrate the potential applications of (67)Ga-DO3A-EA-choline as a radiopharmaceutical for molecular imaging using ((67/68)Ga) SPECT and PET modalities.