排序方式: 共有72条查询结果,搜索用时 15 毫秒
61.
Anis S. Hoayek Gilles R. Ducharme Zaher Khraibani 《Comptes Rendus Mathematique》2017,355(10):1099-1103
In a time series , is said to be an upper record if . Some popular models for records are the Yang–Nevzorov and the Linear Drift models. In this note, we introduce for these models the joint likelihood of the record sequence and the indicators of their occurrence. This likelihood can then be used to obtain estimators of the unknown parameters in the models. It can also be used to derive inferential procedures associated with the selection of a proper model for such data. 相似文献
62.
Ahmed M. Zaher Ahmad M. Moharram Richard Davis Peter Panizzi Makboul A. Makboul 《Natural product research》2015,29(24):2275-2281
Botryodiplodia theobromae Pat. belongs to the endophytic fungi that live within the tissues of medicinal plants and produce bioactive natural products. The endophyte was isolated from the leaves of Dracaena draco L. The LC–MS-based metabolite fingerprinting of the ethyl acetate extract of B. theobromae with antibacterial activity led to the identification of 13 metabolites pertaining to various classes: dipeptides (maculosin and L,L-cyclo(leucylprolyl), alkaloid (norharman), coumarin and isocoumarins (bergapten, meranzin and monocerin), sesquiterpene (dihydrocumambrin A), aldehyde (formyl indanone), fatty alcohol (halaminol A) and fatty acid amide (palmitoleamide, palmitamide, capsi-amide and oleamide). This study reports for the first time, the LC–MS and LC–MS/MS identification of 13 known bioactive metabolites from the antibacterial ethyl acetate extract of B.theobromae isolated from the leaves of D. draco L. 相似文献
63.
Understanding the adsorption of water vapor onto activated carbons is important for designing processes to remove dilute contaminants
from humid gas streams, such as providing protection against chemical warfare agents (CWAs), or against toxic industrial compounds
(TICs) used in a terrorist chemical attack. Water vapor isotherms for Calgon BPL granular activated carbon (GAC), military
ASZM-TEDA GAC, electrospun activated carbon nanofibers (ACnF), Calgon Zorflex™ activated carbon cloth, and Novoloid-based activated carbon fiber cloth (ACFC) are presented. Of particular interest are
the ACFC isotherms, which exhibit an unusually high degree of hydrophobicity. The ACFC isotherms also show a correlation between
water vapor adsorption hysteresis and the level of activation. Water vapor isotherm models from the literature are compared. 相似文献
64.
Wireless Networks - Providing effective sensing coverage of an observation area with reduced set of working nodes for maximum duration of time is an important concern for the development of durable... 相似文献
65.
Wireless Networks - One of the most important requirements for effective UAV–WSN operations is to perform data collection in timely and safe manner. Identifying an effective path in an... 相似文献
66.
M. M. Ghorab A. N. Osman E. Noaman H. I. Heiba N. H. Zaher 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1935-1950
Some novel 5-subistituted amino-3-methylthiophene-2,4-dicarboxylic acid diethyl ester (3–6), 3,5-dimethyl-4-oxo-2-thioxo-1,2,3,4-tetra-hydro-thieno[2,3-d]pyrimi-dine (7), imidazothienopyrimidene (8), and 1,2,4-triazolo-thienopyrimidine (11) were synthesized via a reaction of the isothiocyanate 2 with different reagents. The identification of the new compounds was established by elemental analysis, and IR, 1H NMR, and mass spectral data. Some prepared compounds were tested for their radioprotective and anticancer activities. Compounds 7 and 16 showed significant activities against EAC cells, while compound 5 exhibited radioprotective activity. 相似文献
67.
The title compounds were prepared by four different routes: (1) reaction of cycloalkanopyridazines 3a–e with trichloroacetonitrile in basic medium; (2) reaction of 3a–d with DMF DMA, followed by nucleophilic treatment with a primary amine; (3) reaction of 2‐(dimethylamino)methylene‐cycloalkylidene‐malononitrile with arene diazonium salt, followed by amine treatment; (4) reaction of cycloalkylidenemalononitrile with phenyl or benzoyl isothiocyanate and heating the product with diazoaminobenzene. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:427–433, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10168 相似文献
68.
We consider the problem of large‐data scattering for the quintic nonlinear Schrödinger equation on R × T 2. This equation is critical both at the level of energy and mass. Most notably, we exhibit a new type of profile (a “large‐scale profile”) that controls the asymptotic behavior of the solutions. © 2014 Wiley Periodicals, Inc. 相似文献
69.
The main objective of this research is to improve the dissolution rate of artemisinin (ART) by fabrication with β-cyclodextrin (β-CD) as a hydrophilic carrier. Artemisinin nanoparticles and ART/β-CD complexes were successfully fabricated by means of evaporative precipitation of nanosuspension. Characterization of the samples was done by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and dissolution tester. Percent dissolution efficiency, mean dissolution time, relative dissolution and similarity factor were calculated for the statistical analysis of dissolution data. FT-IR showed some interaction between ART and β-CD, which can be due to the formation of some ART/β-CD complexes. XRD study indicated the presence of two polymorphs of ART, i.e. orthorhombic and triclinic form. Original ART particles and ART nanoparticles fabricated were orthorhombic whereas the free ART in the ART/β-CD complexes (not forming complex with β-CD) was of triclinic form. The crystallinity of ART reduced and more and more ART/β-CD complexes were formed with increasing concentration of β-CD as indicated by the DSC, XRD and FT-IR studies. Artemisinin nanoparticles and ART/β-CD complexes showed significantly faster dissolution than the pure drug due to smaller size (larger surface area), formation of the inclusion complex with β-CD, formation of the triclinic form for remaining free ART (not forming complex with β-CD), and amorphous state formation. Evaporative precipitation of nanosuspension was able to successfully fabricate artemisinin in the nanoparticles and complex forms with significantly faster dissolution rates than that of the original artemisinin. The two polymorphic forms of ART were also fabricated and studied. 相似文献
70.
M. M. Ghorab A. N. Osman E. Noaman H. I. Heiba N. H. Zaher 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):1983-1996
The synthesis of novel thioureido derivatives 3, 8, and 10; biscompounds 7, 9, and 11; and tetracyclic compounds 5, 6, and 16 utilizing 5-isothiocyanato-3-methyl-thiophene-2,4-dicarboxylic acid diethyl ester 2 are reported. The structures of these compounds were confirmed by microanalyses and IR, 1H NMR, and mass spectroscopy. Preliminary biological studies of some of the synthesized compounds showed promising radioprotective and anticancer activities. 相似文献