Search results for "Diene"
showing 10 items of 623 documents
Pharmacogenomic and molecular docking studies on the cytotoxicity of the natural steroid wortmannin against multidrug-resistant tumor cells
2014
Wortmannin is a cytotoxic compound derived from the endophytic fungi Fusarium oxysporum, Penicillium wortmannii and Penicillium funiculosum that occurs in many plants, including medicinal herbs. The rationale to develop novel anticancer drugs is the frequent development of tumor resistance to the existing antineoplasic agents. Therefore, it is mandatory to analyze resistance mechanisms of novel drug candidates such as wortmannin as well to bring effective drugs into the clinic that have the potential to bypass or overcome resistance to established drugs and to substantially increase life span of cancer patients. In the present project, we found that P-glycoprotein-overexpressing tumor cells…
Design and characterization of the SiPM tracking system of NEXT-DEMO, a demonstrator prototype of the NEXT-100 experiment
2013
NEXT-100 experiment aims at searching the neutrinoless double-beta decay of the Xe-136 isotope using a TPC filled with a 100 kg of high-pressure gaseous xenon, with 90% isotopic enrichment. The experiment will take place at the Laboratorio Subterraneo de Canfranc (LSC), Spain. NEXT-100 uses electroluminescence (EL) technology for energy measurement with a resolution better than 1% FWHM. The gaseous xenon in the TPC additionally allows the tracks of the two beta particles to be recorded, which are expected to have a length of up to 30 cm at 10 bar pressure. The ability to record the topological signature of the beta beta 0 nu events provides a powerful background rejection factor for the bet…
Polar organic marker compounds in PM2.5 aerosol from a mixed forest site in western Germany
2008
The molecular composition of PM2.5 (particulate matter with an aerodynamic diameter2.5 microm) aerosol samples collected during a very warm and dry 2003 summer period at a mixed forest site in Jülich, Germany, was determined by gas chromatography/mass spectrometry in an effort to evaluate photooxidation products of biogenic volatile organic compounds (BVOCs) and other markers for aerosol source characterization. Six major classes of compounds represented by twenty-four individual organic species were identified and measured, comprising tracers for biomass combustion, short-chain acids, fatty acids, sugars/sugar alcohols, and tracers for the photooxidation of isoprene and alpha-/beta-pinene.…
Towards an accurate molecular orbital theory for excited states : Ethene, butadiene, and hexatriene
1993
A newly proposed quantum chemical approach for ab initio calculations of electronic spectra of molecular systems is applied to the molecules ethene, trans‐1,3‐butadiene, and trans‐trans‐1,3,5‐hexatriene. The method has the aim of being accurate to better than 0.5 eV for excitation energies and is expected to provide structural and physical data for the excited states with good reliability. The approach is based on the complete active space (CAS) SCF method, which gives a proper description of the major features in the electronic structure of the excited state, independent of its complexity, accounts for all near degeneracy effects, and includes full orbital relaxation. Remaining dynamic ele…
Linked cyclopentadienyl-amido titanium catalysts supported on pyridylethylsilane-modified silica for heterogeneous ethylene homo- and copolymerization
2003
Abstract Linked cyclopentadienyl-amido titanium dimethyl and dichloro complexes, Ti(η 5 :η 1 -C 5 Me 4 SiMe 2 N t Bu)X 2 (X=Me, Cl), were reacted with trityl tetrakis(pentafluorophenyl)borate (TB), Ph 3 C + [B(C 6 F 5 ) 4 ] − , and methylaluminoxane (MAO), followed by treatment with toluene suspension of pyridylethylsilane-modified silica, to give two new supported-type titanium catalysts, PySTiTB and PySTiMAO. PySTiTB polymerized ethylene in the presence of triisobutylaluminum (TIBA) in hexane at 60 °C and 5 bar with slightly higher activity than the corresponding homogeneous system under the same conditions. PySTiMAO showed relatively high activity even without any use of alkylaluminum co…
Interaction of half-sandwich alkylmolybdenum(III) complexes with B(C6F5)3. The X-ray structure of [CpMo(η4-C4H6)(μ-Cl)(μ-CH2)(O)MoCp][CH3B(C6F5)3]
2001
Abstract The reactions of the half-sandwich molybdenum(III) complexes CpMo(η 4 -C 4 H 4 R 2 )(CH 3 ) 2 , where Cpη 5 -C 5 H 5 and RH or CH 3 , with equimolar amounts of B(C 6 F 5 ) 3 have been investigated in toluene. EPR monitoring shows the formation of an addition product which does not readily react with Lewis bases such as ethylene, pyridine, or PMe 3 . The analysis of the EPR properties and the X-ray structure of a decomposition product obtained from dichloromethane, [CpMo(η 4 -C 4 H 6 )(μ-Cl)(μ-CH 2 )(O)MoCp][CH 3 B(C 6 F 5 ) 3 ], indicate that the borane attack has occurred at the methyl position.
Synthèse et caractérisation de phosphine, borane, amine sur plateforme ferrocène polyfonctionnelle
2016
Ferrocene platforms are useful in coordination chemistry and catalysis thanks to their robustness and versatile functionalization. Ferrocene backbone allows the implantation of several key functional groups in a restricted space, inducing close proximity and potential polyfunctional cooperation (see for instance ferrocenyl polyphosphine chemistry). Ansa ferrocene and ferrocene bearing conformational control inducing groups maximizing the proximity of key groups have been widely reported.The first part of this thesis focuses on the synthesis of new borylated cyclopentadienyl, and their use in formation of borylated metallocenes bearing conformational constraints. NMR analysis and DFT calcula…
On the enhancement of stereoselection by cooperation between chiral auxiliaries. Asymmetric diels-alder reactions with fumaric acid bis ((S)-proline …
1989
Abstract Fumaric acid bis ((S)-proline benzyl ester) amide reacts with cyclopentadiene in thermal and Lewis acid catalyzed Diels-Alder reactions to give the cycloadducts with high yields and diastereomeric ratios up to 100:1.
Ab initio SCF and CI calculations on the barrier to internal rotation of 1,3-butadiene
1972
Ab initio SCF and CI calculations employing a set of gaussian lobe functions have been carried out for the ground and excited states of five geometrical C4H6-structures occurring in the course of rotation from cis-butadiene to the trans-isomer. The rotational potential curves are discussed for the ground and excited states. Particularly the potential curve of the lowest triplet state is considered in this connection thereby substantiating quantitatively the proposed mechanism for induced dimerisation of C4H6. Possible assignments of the lowest singlet excited states in trans-butadiene are discussed.
The Program of Health Volunteer Promoters for OlderAdults: The Well-Being of the Volunteers at Leisure Time
2018
The study of ageing processes has gained increased attention in recent years, partly due to the growth of this population group (United Nations, World population prospects: The 2015 revision. New York: United Nations Department of Economic and Social Affairs. https://esa.un.org/unpd/wpp/publications/files/key_findings_wpp_2015.pdf. Accessed 25 Sep 2016, 2015). Research into this area has focused on older adult well-being (Au et al, Clinical Gerontologist 38:203–210, 2015) and the identification of factors having an influence on well-being at this stage of the life cycle (Carstensen, Current Directions in Psychological Science 4:151–156, 1995). These lines of research have emphasized the con…