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1.
A. Sánchez-Lavega A. Salazar A. Ocariz L. Pottier E. Gomez L.M. Villar E. Macho 《Applied Physics A: Materials Science & Processing》1997,65(1):15-22
Received: 16 September 1996/Accepted: 6 January 1997 相似文献
2.
Roberto Martínez Corte C. Eduardo Salazar E. Olivia Linzaga E. Irma 《Journal of heterocyclic chemistry》1994,31(4):1061-1063
Catalytic hydrogenation of o-nitrophenylbenz[a], benz[c], dibenz[a,h] and dibenz[a,g]acridinones using Pd/C as catalyst, at 60 psi of pressure, gave the hiterto unknown benzoquinoacridine N-oxides and benzo-pyranonaphthyridine N-oxides. The structure of all products was corroborated by ir, 1H- and 13C-nmr and mass spectra data. 相似文献
3.
J. Martinez Salazar R. K. Bayer T. A. Ezquerra F. J. Baltá Calleja 《Colloid and polymer science》1989,267(5):409-413
The morphology and structure of high molecular weight linear polyethylene (M
w 450000) filled with carbon black and processed using molds that introduce an elongational flow component during injection molding has been examined using electron microscopy and x-ray diffraction techniques. The study of fracture surfaces reveals the display of shish-kebabs oriented along the injection direction with segregated longitudinal channels of carbon black particles. Molecular and lamellar changes in orientation are, furthermore, studied across the thickness of the moldings. It is shown that addition of carbon black particles to injection-molded polyethylene induces significant changes in lamellar orientation. Thus, while lamellar overgrowth proceeds perpendicular to the fiber axes within carbon free channels, lamellae grow randomly within carbon-enriched regions where flow is less pronounced. 相似文献
4.
José I. Concepción Cosme G. Francisco Rosendo Hernández José A. Salazar Ernesto Suárez 《Tetrahedron letters》1984,25(18):1953-1956
Photolysis of several hydroxy compounds in presence of iodosobenzene diacetate and iodine leads to alkoxy radical derivatives which undergo intramolecular hydrogen abstraction to produce cyclic ethers in good yield. 相似文献
5.
All type-D vacuum (nonnull orbit and null orbit) solutions with are exhibited in canonical coordinates. The nonnull orbit metrics with contain four families of solutions: the static Levi-Cività metrics, the nondivergingD's, the divergingD's, and the diverging and twisting solutions. The null orbit metrics subdivide into two subclasses of solutions: the divergenceless null orbitD's, and the diverging and twisting null orbit solution. 相似文献
6.
7.
Zhang C Occi J Masurekar P Barrett JF Zink DL Smith S Onishi R Ha S Salazar O Genilloud O Basilio A Vicente F Gill C Hickey EJ Dorso K Motyl M Singh SB 《Journal of the American Chemical Society》2008,130(36):12102-12110
Bacterial resistance to antibiotics, particularly to multiple drug resistant antibiotics, is becoming cause for significant concern. The only really viable course of action is to discover new antibiotics with novel mode of actions. Thiazolyl peptides are a class of natural products that are architecturally complex potent antibiotics but generally suffer from poor solubility and pharmaceutical properties. To discover new thiazolyl peptides potentially with better desired properties, we designed a highly specific assay with a pair of thiazomycin sensitive and resistant strains of Staphylococcus aureus, which led to the discovery of philipimycin, a new thiazolyl peptide glycoside. It was isolated along with an acid-catalyzed degradation product by bioassay-guided fractionation. Structure of both compounds was elucidated by extensive application of 2D NMR, 1D TOCSY, and HRESIFT-MS/MS. Both compounds showed strong antibacterial activities against gram-positive bacteria including MRSA and exhibited MIC values ranging from 0.015 to 1 microg/mL. Philipimycin was significantly more potent than the degradation product. Both compounds showed selective inhibition of protein synthesis, indicating that they targeted the ribosome. Philipimycin was effective in vivo in a mouse model of S. aureus infection exhibiting an ED50 value of 8.4 mg/kg. The docking studies of philipimycin suggested that a part of the molecule interacts with the ribosome and another part with Pro23, Pro22, and Pro26 of L11 protein, which helped in explaining the differential of activities between the sensitive and resistant strains. The design and execution of the bioassay, the isolation, structure, in vitro and in vivo antibacterial activity, and docking studies of philipimycin and its degradation product are described. 相似文献
8.
G. López L. A. Barrera Y. Garibo H. Hernández J. C. Salazar C. A. Vargas 《International Journal of Theoretical Physics》2004,43(10):2009-2021
The constants of motion of the following systems are deduced: a relativistic particle with linear dissipation; a no-relativistic particle with a time explicitly depending force; a no-relativistic particle with a constant force and time depending mass; and a relativistic particle under a conservative force with position depending mass. The Hamiltonian for these systems, which is determined by getting the velocity as a function of position and generalized linear momentum, can be found explicitly at first approximation for the first system. The Hamiltonians for the other systems are kept implicitly in their expressions for their constants of motion. 相似文献
9.
María G. Hernández-Cruz Micaela Hernández-Sandoval María J. Rosales-Hoz Verónica Salazar Francisco J. Zuno-Cruz 《Journal of organometallic chemistry》2011,696(10):2177-4078
The reaction between [Ru3(CO)10(NCMe)2] and [AuClPPh3] gave compound [Ru3(CO)10(μ-Cl)(μ-AuPPh3)] (1) in quantitative yield under very mild conditions. The reaction of 1 with 4-mercaptopyridine (4-pyS) using ultrasonic reaction conditions gave the heteronuclear compound [Ru3(CO)10(μ-AuPPh3)(μ-SC5H4N)] (2) in moderate yield. There was no spectroscopic evidence that indicates the formation of the hydride isolobal analog in this reaction. The homonuclear cluster [Ru3(CO)8(μ-H)(μ-SC5H4N)(μ-dppe)] (3) was prepared by a selective reaction employing the ruthenium-diphosphine derivative [Ru3(CO)10(μ-dppe)] (dppe = 1,2-bis(diphenylphosphine)ethane) with 4-pyS in THF solution. The isolobal analog to compound 3, compound [Ru3(CO)8(μ-AuPPh3)(μ-SC5H4N)(μ-dppe)] (4) was synthesized by the reaction between compound 2 and dppe in refluxing dichloromethane. Compounds 1-4 were characterized in solution by spectroscopic methods and the molecular structure of compounds 2 and 3 in the solid state was obtained by single crystal X-ray diffraction studies. 相似文献
10.