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1.
M. G. Kurella L. G. Vorontsova S. V. Baranin A. Dib V. A. Dorokhov 《Russian Chemical Bulletin》1991,40(1):156-160
X-ray diffraction has been used to establish the crystalline and molecular structure of the intracomplex 2-[(dibutylboryloxy)(butyl)borylamino]4-methylpyridine. In the crystal, the molecule forms weak intermolecular N(H)...O hydrogen bonds. The bicyclic portion of the molecule is nearly planar. From the bond lengths in the ring, which incorporates boron atoms of differing hybridization (sp3 and sp2), it follows that delocalization of electron density extends only over the amidine fragment. Quantum chemical calculations (MO LCAO, version CNINDO/2) show that the electron density at the endocyclic nitrogen of the aminopyridine system coordinated with boron is lower than that at the endocyclic nitrogen of the aminopyridine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 173–177, January, 1991. 相似文献
2.
Etourneau J Ammar A Villesuzanne A Villeneuve G Chevalier B Whangbo MH 《Inorganic chemistry》2003,42(14):4242-4244
Electrical resistivity, magnetic susceptibility, and electron paramagnetic resonance measurements were carried out for cubic hexaboride KB(6), which is one electron short of completely filling its conduction band. It is found that KB(6) is not metallic and has localized spins. KB(6) exhibits a highly unusual hysteresis in the magnetic susceptibility below 100 K, which suggests that it undergoes a slow relaxation process. 相似文献
3.
Mohamed Ibrahim Younis Xiaofeng Ren Azalldeen Kazal Alzubaidi Khaled Fahmy Mahmoud Ammar B. Altemimi Francesco Cacciola Husnain Raza Anubhav Pratap-Singh Tarek Gamal Abedelmaksoud 《Molecules (Basel, Switzerland)》2022,27(14)
The total phenolic content (TPC) from Cassia javanica L. petals were extracted using ethanolic solvent extraction at concentrations ranging from 0 to 90% and an SCF-CO2 co-solvent at various pressures. Ultrasound-assisted extraction parameters were optimized using response surface methodology (RSM). Antioxidant and anticancer properties of total phenols were assessed. An SCF-CO2 co-solvent extract was nano-encapsulated and applied to sunflower oil without the addition of an antioxidant. The results indicated that the best treatment for retaining TPC and total flavonoids content (TFC) was SCF-CO2 co-solvent followed by the ultrasound and ethanolic extraction procedures. Additionally, the best antioxidant activity by β-carotene/linoleic acid and DPPH free radical-scavenging test systems was observed by SCF-CO2 co-solvent then ultrasound and ethanolic extraction methods. SCF-CO2 co-solvent recorded the highest inhibition % for PC3 (76.20%) and MCF7 (98.70%) and the lowest IC50 value for PC3 (145 µ/mL) and MCF7 (96 µ/mL). It was discovered that fortifying sunflower oil with SCF-CO2 co-solvent nanoparticles had a beneficial effect on free fatty acids and peroxide levels. The SCF-CO2 method was finally found to be superior and could be used in large-scale processing. 相似文献
4.
H. O. Ammar M. Ghorab D. M. Mostafa T. S. Makram R. M. Ali 《Journal of inclusion phenomena and macrocyclic chemistry》2013,77(1-4):121-134
Etodolac, being a practically insoluble candidate, exhibits certain toxic effects and a limited bioavailability. Upon chronic use, it causes gastro-intestinal injury and increases the risk of ulcer complications. The approach of this study was to improve the physicochemical properties of the drug utilizing complexation phenomenon with β-, methyl-β- and hydroxypropyl-β-cyclodextrins, which may enhance the aqueous solubility and dissolution rate of etodolac, in an effort to increase oral bioavailability. In certain instances, this approach can be used to increase drug solubility, improve organoleptic properties and maximize the gastrointestinal tolerance by reducing drug irritation after oral administration. Differential UV measurements as well as continuous variation plots revealed the formation of equimolar complex with hydroxypropyl-β-cyclodextrin and 1:2 complexes with β-cyclodextrin and its methyl derivative. Differential scanning calorimetry (DSC), X-ray and FT-IR measurements were applied to prove inclusion complex formation and characterize the complexes. These results lend support to the idea that solubilization of etodolac is mainly related to inclusion complex formation and to a lesser extent to cyclodextrin aggregates. Understanding the factors that influence the performance of etodolac, will allow us to state that molecular encapsulation of the drug and other modifications with appropriate hydroxylation or methylation of parent β-cyclodextrin is able to overcome its problems and facilitate safe and efficient delivery of the drug. 相似文献
5.
Albrecht H Binder U Harder G Lembke-Koppitz I Philipp A Schmidt-Parzefall W Schröder H Schulz HD Wurth R Donker JP Drescher A Matthiesen U Scheck H Spaan B Spengler J Wegener aD Gabriel JC Schubert KR Stiewe J Waldi R Weseler S Brown NN Edwards KW Frisken WR Fukunaga C Gilkinson DJ Gingrich DM Goddard M Kapitza H Kim PC Kutschke R MacFarlane DB McKenna JA McLean KW Nilsson AW Orr RS Padley P Patel PM Prentice JD Seywerd HC Stacey BJ Yoon T Yun JC Ammar R Coppage D Davis R Kanekal S Kwak N 《Physical review letters》1986,56(6):549-552
6.
Cinabro D Henderson S Kinoshita K Liu T Saulnier M Wilson R Yamamoto H Sadoff AJ Ammar R Ball S Baringer P Coppage D Copty N Davis R Hancock N Kelly M Kwak N Lam H Kubota Y Lattery M Nelson JK Patton S Perticone D Poling R Savinov V Schrenk S Wang R Alam MS Kim IJ Nemati B O'Neill JJ Romero V Severini H Sun CR Zoeller MM Crawford G Fulton R Fujino D Gan KK Kagan H Kass R Lee J Malchow R Morrow F Skovpen Y Sung M White C Whitmore J Wilson P Butler F Fu X Kalbfleisch G Lambrecht M Ross WR 《Physical review letters》1993,70(24):3700-3704
7.
Performance scaling of passively mode-locked ultrashort-pulse fiber oscillators in terms of average power, peak power, and pulse energy is demonstrated. A very-large-mode-area fiber laser in an all-positive group-velocity-dispersion ring cavity configuration with intracavity spectral filter, mode-locked by nonlinear polarization evolution, emits 66 W of average power at 76 MHz repetition rate, corresponding to 0.9 μJ pulse energy. The pulses are dechirped to 91 fs outside the cavity with an average power of 60 W remaining after the compressor. The generated pulse peak power is as high as 7 MW. 相似文献
8.
Eisenstein BI Ernst J Gladding GE Gollin GD Hans RM Johnson E Karliner I Marsh MA Plager C Sedlack C Selen M Thaler JJ Williams J Edwards KW Sadoff AJ Ammar R Bean A Besson D Zhao X Anderson S Frolov VV Kubota Y Lee SJ Poling R Smith A Stepaniak CJ Urheim J Ahmed S Alam MS Athar SB Jian L Ling L Saleem M Timm S Wappler F Anastassov A Eckhart E Gan KK Gwon C Hart T Honscheid K Hufnagel D Kagan H Kass R Pedlar TK Thayer JB von Toerne E Zoeller MM Richichi SJ Severini H Skubic P Undrus A Savinov V 《Physical review letters》2001,87(6):061801
Using 12.7 fb(-1) of data collected with the CLEO detector at CESR, we observed two-photon production of the cc states chi(c0) and chi(c2) in their decay to pi(+)pi(-)pi(+)pi(-). We measured gamma(gammagamma)(chi(c))xB(chi(c)-->pi(+)pi(-)pi(+)pi(-)) to be 75+/-13(stat)+/-8(syst) eV for the chi(c0) and 6.4+/-1.8(stat)+/-0.8(syst) eV for the chi(c2), implying gamma(gammagamma)(chi(c0)) = 3.76+/-0.65(stat)+/-0.41(syst)+/-1.69(br) keV and gamma(gammagamma)(chi(c2)) = 0.53+/-0.15(stat)+/-0.06(syst)+/-0.22(br) keV. Also, cancellation of dominant experimental and theoretical uncertainties permits a precise comparison of gamma(gammagamma)(chi(c0))/gamma(gammagamma)(chi(c2)), evaluated to be 7.4+/-2.4(stat)+/-0.5(syst)+/-0.9(br), with QCD-based predictions. 相似文献
9.
A. E. Cárcamo Hernández Claudio O. Dib Alfonso R. Zerwekh 《The European Physical Journal C - Particles and Fields》2014,74(4):1-27
In scenarios of strongly coupled electroweak symmetry breaking, heavy composite particles of different spin and parity may arise and cause observable effects on signals that appear at loop levels. The recently observed process of Higgs to $\gamma \gamma $ at the LHC is one of such signals. We study the new constraints that are imposed on composite models from $H\rightarrow \gamma \gamma $ , together with the existing constraints from the high precision electroweak tests. We use an effective chiral Lagrangian to describe the effective theory that contains the Standard Model spectrum and the extra composites below the electroweak scale. Considering the effective theory cutoff at $\Lambda = 4\pi v \sim 3\text { TeV}$ , consistency with the $T$ and $S$ parameters and the newly observed $H\rightarrow \gamma \gamma $ can be found for a rather restricted range of masses of vector and axial-vector composites from 1.5 to 1.7 and 1.8 to 1.9 TeV, respectively, and only provided a non-standard kinetic mixing between the $W^{3}$ and $B^{0}$ fields is included. 相似文献
10.
Lecaplain C Ortaç B Machinet G Boullet J Baumgartl M Schreiber T Cormier E Hideur A 《Optics letters》2010,35(19):3156-3158
We report the generation of high-energy high-peak power pulses in an all-normal dispersion fiber laser featuring large-mode-area photonic crystal fibers. The self-starting chirped-pulse fiber oscillator delivers 11 W of average power at 15.5 MHz repetition rate, resulting in 710 nJ of pulse energy. The output pulses are dechirped outside the cavity from 7 ps to nearly transform-limited duration of 300 fs, leading to pulse peak powers as high as 1.9 MW. Numerical simulations reveal that pulse shaping is dominated by the amplitude modulation and spectral filtering provided by a resonant semiconductor saturable absorber. 相似文献