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471.
Chakraborty TK Koley D Ravi R Krishnakumari V Nagaraj R Kunwar AC 《The Journal of organic chemistry》2008,73(22):8731-8744
Sugar amino acid based 24-membered macrocyclic C2-symmetric cationic peptides were designed and synthesized. The cationic group was introduced in the sugar amino acids. The conformation of these cyclic compounds was ascertained through NMR techniques, which proved they were amphipathic in nature. All the compounds were bacteriolytic, showed good activity against the Gr(+ve) and Gr(-ve) bacteria, and exhibited low hemolytic activity. 相似文献
472.
Gopi D Govindaraju KM Victor CA Kavitha L Rajendiran N 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(5):1243-1245
In the present work, the synthesis and characterization of nano-HAP powders by a novel ultrasonic coupled sol-gel synthesis is reported. The obtained powders were sintered by conventional means at different temperatures. In addition to this, HAP powders prepared through the sol-gel method without the aid of the ultrasonic waves is also studied. The obtained nano-HAP powders were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopic (SEM) techniques. The results have proved that the nano-HAP powders synthesized by ultrasonic coupled sol-gel synthesis showed remarkable reduction in the particle size when compared with the conventional sol-gel method and hence these powders could be used as a coating material in biomedical applications. 相似文献
473.
Mohan S Thind KS Sharma G Gerward L 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(5):1173-1179
Spectroscopic and physical properties of Nd(3+) doped sodium lead flouro- and chloro-borate glasses of the type 20NaX-30PbO-49.5B(2)O(3)-0.5Nd(2)O(3) (X=F and Cl) have been investigated. Optical absorption spectra have been used to determine the Slater Condon (F(2), F(4), and F(6)), spin orbit xi(4f) and Racah parameters (E(1), E(2), and E(3)). The oscillator strengths and the intensity parameters Omega(2), Omega(4) and Omega(6) have been determined by the Judd-Ofelt theory, which in turn provide the radiative transition probability (A), total transition probability (A(T)), radiative lifetime (tau(R)) and branching ratio (beta) for the fluorescent level (4)F(3/2). The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor (Omega(4)/Omega(6)), the value of which is in the range of 0.2-1.5, typical for Nd(3+) in different laser hosts. Nephelauxetic effect results in a red shift in the energy levels of Nd(3+) for chloroborate glass. The radiative transition probability of the potential lasing transition (4)F(3/2)-->(4)I(11/2) of Nd(3+) ions is found to be higher for flouroborate as compared to chloroborate glass. 相似文献
474.
An efficient Pd-catalyzed domino reaction of α,α-dialkyl-(2-bromoaryl)methanols to 6,6-dialkyl-6H-benzo[c]chromenes is presented. Their formation can be explained via a five membered Pd(II)-cycle that efficiently involves a domino homocoupling with the second molecule, β-carbon cleavage, and finally intramolecular Buchwald-Hartwig cyclization. This domino process effectively involves breaking of five σ-bonds (2C-Br, 2O-H, and a C-C) and formation of two new σ-bonds (C-C and C-O). This mechanistic pathway is unprecedented and further illustrates the power of transition metal catalysis. 相似文献
475.
476.
Bandyopadhyay A Jadhav SV Gopi HN 《Chemical communications (Cambridge, England)》2012,48(57):7170-7172
Synthesis, crystal conformations of α/γ(4)-hybrid peptide helices containing proteinogenic amino acid side-chains, and the analogy with the α-helix are reported. Results suggest that α/γ(4)-hybrid peptides adopted helical conformations with 12-membered H-bond pseudocycles in single crystals. 相似文献
477.
A method to convert 2-hydroxy glycal ester to the corresponding 2-deoxy-2-C-alkyl glycal in a facile manner, through key reactions including (i) C-allylation at C-1, (ii) Wittig reaction, and (iii) Cope rearrangement of a 1,5-diene derivative, is reported. The α-anomer of the 1,5-diene derivative underwent Cope rearrangement to afford 2-deoxy-2-C-glycal derivative, whereas the β-anomer was found to be unreactive. Employing this sequence, 3,4,6-tri-O-benzyl-2-O-acetyl-1,5-anhydro-d-arabino-hex-1-enitol was transformed to 3,4,6-tri-O-benzyl-2-deoxy-2-C-alkyl-1,5-anhydro-D-arabino-hex-1-enitol. 2-Deoxy-2-C-alkyl glycal derivative is a suitable glycosyl donor to prepare 2-deoxy-2-C-alkyl glycosides, mediated through haloglycosylation and a subsequent dehalogenation. A number of 2-deoxy-2-C-alkyl glycosides, with both glycosyl and nonglycosyl moieties at the reducing end, are thus prepared from the glycal. 相似文献
478.
Adler SS Afanasiev S Aidala C Ajitanand NN Akiba Y Alexander J Amirikas R Aphecetche L Aronson SH Averbeck R Awes TC Azmoun R Babintsev V Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bazilevsky A Belikov S Berdnikov Y Bhagavatula S Boissevain JG Borel H Borenstein S Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Camard X Chai JS Chand P Chang WC Chernichenko S Chi CY Chiba J Chiu M Choi IJ Choi J Choudhury RK Chujo T 《Physical review letters》2006,97(5):052301
Azimuthal correlations of jet-induced high-p(T) charged hadron pairs are studied at midrapidity in Au+Au collisions at sqrt[s(NN)]=200 GeV. The distribution of jet-associated partner hadrons (1.0
相似文献
479.
Adler SS Afanasiev S Aidala C Ajitanand NN Akiba Y Alexander J Amirikas R Aphecetche L Aronson SH Averbeck R Awes TC Azmoun R Babintsev V Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bazilevsky A Belikov S Berdnikov Y Bhagavatula S Boissevain JG Borel H Borenstein S Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Camard X Chai JS Chand P Chang WC Chernichenko S Chi CY Chiba J Chiu M Choi IJ Choi J Choudhury RK Chujo T 《Physical review letters》2006,96(3):032001
The invariant differential cross section for inclusive electron production in p+p collisions at [FORMULA: SEE TEXT] has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over the transverse momentum range 0.4相似文献
480.
Adler SS Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Jamel A Alexander J Aoki K Aphecetche L Armendariz R Aronson SH Atomssa ET Averbeck R Awes TC Babintsev V Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bauer F Bazilevsky A Belikov S Bjorndal MT Boissevain JG Borel H Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Camard X Chand P Chang WC Chernichenko S Chi CY Chiba J Chiu M Choi IJ Choudhury RK Chujo T Cianciolo V 《Physical review letters》2006,96(1):012304
J/psi production in d + Au and p + p collisions at square root of S(NN) = 200 GeV has been measured by the PHENIX experiment at rapidities -2.2 < y < +2.4. The cross sections and nuclear dependence of J/psi production versus rapidity, transverse momentum, and centrality are obtained and compared to lower energy p + A results and to theoretical models. The observed nuclear dependence in d + Au collisions is found to be modest, suggesting that the absorption in the final state is weak and the shadowing of the gluon distributions is small and consistent with Dokshitzer-Gribov-Lipatov-Altarelli-Parisi-based parametrizations that fit deep-inelastic scattering and Drell-Yan data at lower energies. 相似文献