排序方式: 共有73条查询结果,搜索用时 31 毫秒
11.
Wireless Personal Communications - Research interest has been focused on vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication systems, known as V2X technologies, namely in... 相似文献
12.
Mohsan Nawaz Faiza Jan Iftikhar Musa Kaleem Baloch Wajid Rehman Iftikhar Ahmad 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(13):2169-2172
Single-phase giant magnetoresistance (GMR) compounds were prepared by doping the parent compound, NdMnO3, with Sr at Nd sites. The resistivity of the doped samples showed two prominent regions (Δρ/ΔT < 0, insulating and Δρ/ΔT > 0, metallic). The doped samples exhibited an enhancement in double exchange (DE) interactions causing an increase in T
c (transition temperature). Magnetic field decreased the resistance of all the samples because of the suppression of spin fluctuations
and an increase in disorder in the system. The polaron and variable range hopping (VRH) models were good for studying the
transport mechanism of electrons and understand their behavior at T > T
c. 相似文献
13.
Faiza Derrab 《Proceedings of the American Mathematical Society》2007,135(6):1803-1815
We consider nonlinear partial differential equations with several Fuchsian variables of type , where is a Fuchsian principal part of weight zero. We prove existence and uniqueness of a global solution to this problem in the space of holomorphic functions with respect to the Fuchsian variable and in Gevrey spaces with respect to the other variable . The method of proof is based on the application of the fixed point theorem in some Banach algebras defined by majorant functions that are suitable to this kind of equation.
14.
Muhammad Umar Aslam Khan Iqra Iqbal Mohamed Nainar Mohamed Ansari Saiful Izwan Abd Razak Mohsin Ali Raza Amna Sajjad Faiza Jabeen Mohd Riduan Mohamad Norhana Jusoh 《Molecules (Basel, Switzerland)》2021,26(19)
The present research is based on the fabrication preparation of CS/PVA/GG blended hydrogel with nontoxic tetra orthosilicate (TEOS) for sustained paracetamol release. Different TEOS percentages were used because of their nontoxic behavior to study newly designed hydrogels’ crosslinking and physicochemical properties. These hydrogels were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and wetting to determine the functional, surface morphology, hydrophilic, or hydrophobic properties. The swelling analysis in different media, degradation in PBS, and drug release kinetics were conducted to observe their response against corresponding media. The FTIR analysis confirmed the components added and crosslinking between them, and surface morphology confirmed different surface and wetting behavior due to different crosslinking. In various solvents, including water, buffer, and electrolyte solutions, the swelling behaviour of hydrogel was investigated and observed that TEOS amount caused less hydrogel swelling. In acidic pH, hydrogels swell the most, while they swell the least at pH 7 or higher. These hydrogels are pH-sensitive and appropriate for controlled drug release. These hydrogels demonstrated that, as the ionic concentration was increased, swelling decreased due to decreased osmotic pressure in various electrolyte solutions. The antimicrobial analysis revealed that these hydrogels are highly antibacterial against Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram negative (Pseudomonas aeruginosa and Escherichia coli) bacterial strains. The drug release mechanism was 98% in phosphate buffer saline (PBS) media at pH 7.4 in 140 min. To analyze drug release behaviour, the drug release kinetics was assessed against different mathematical models (such as zero and first order, Higuchi, Baker–Lonsdale, Hixson, and Peppas). It was found that hydrogel (CPG2) follows the Peppas model with the highest value of regression (R2 = 0.98509). Hence, from the results, these hydrogels could be a potential biomaterial for wound dressing in biomedical applications. 相似文献
15.
Bushra Asad Taimoor Khan Faiza Zareen Gul Muhammad Asad Ullah Samantha Drouet Sara Mikac Laurine Garros Manon Ferrier Shankhamala Bose Thibaut Munsch Duangjai Tungmunnithum Arnaud Lanoue Nathalie Giglioli-Guivarch Christophe Hano Bilal Haider Abbasi 《Molecules (Basel, Switzerland)》2021,26(15)
In vitro cultures of scarlet flax (Linum grandiflorum L.), an important ornamental flax, have been established as a new possible valuable resource of lignans and neolignans for antioxidant and anti-inflammatory applications. The callogenic potential at different concentrations of α-naphthalene acetic acid (NAA) and thidiazuron (TDZ), alone or in combinations, was evaluated using both L. grandiflorum hypocotyl and cotyledon explants. A higher callus induction frequency was observed on NAA than TDZ, especially for hypocotyl explants, with a maximum frequency (i.e., 95.2%) on 1.0 mg/L of NAA. The presence of NAA (1.0 mg/L) in conjunction with TDZ tended to increase the frequency of callogenesis relative to TDZ alone, but never reached the values observed with NAA alone, thereby indicating the lack of synergy between these two plant growth regulators (PGRs). Similarly, in terms of biomass, NAA was more effective than TDZ, with a maximum accumulation of biomass registered for medium supplemented with 1.0 mg/L of NAA using hypocotyls as initial explants (DW: 13.1 g). However, for biomass, a synergy between the two PGRs was observed, particularly for cotyledon-derived explants and for the lowest concentrations of TDZ. The influence of these two PGRs on callogenesis and biomass is discussed. The HPLC analysis confirmed the presence of lignans (secoisolariciresinol (SECO) and lariciresinol (LARI) and neolignan (dehydrodiconiferyl alcohol [DCA]) naturally accumulated in their glycoside forms. Furthermore, the antioxidant activities performed for both hypocotyl- and cotyledon-derived cultures were also found maximal (DPPH: 89.5%, FRAP 866: µM TEAC, ABTS: 456 µM TEAC) in hypocotyl-derived callus cultures as compared with callus obtained from cotyledon explants. Moreover, the anti-inflammatory activities revealed high inhibition (COX-1: 47.4% and COX-2: 51.1%) for extract of hypocotyl-derived callus cultures at 2.5 mg/L TDZ. The anti-inflammatory action against COX-1 and COX-2 was supported by the IC50 values. This report provides a viable approach for enhanced biomass accumulation and efficient production of (neo)lignans in L. grandiflorum callus cultures. 相似文献
16.
Faiza Ammar-Khodja Saliha Guermouche Moulay-Hassane Guermouche Patrick Judenstein Jean-Pierre Bayle 《Chromatographia》2009,70(3-4):497-502
A new monotropic liquid crystal with crown ether substituent called Substance M was synthetized and characterized by several methods: 1H NMR, hot stage polarizing microscopy, differential scanning calorimetry and inverse gas chromatography. Annealing experiments with inverse gas chromatography confirmed the monotropic behavior of the compound. Isothermally in the nematic state, solute probes chosen were chromatographed after different heating times. The changes of the corresponding retention times were studied. 相似文献
17.
Collagen is the most abundant protein in humans and animals, comprising of one third of the total proteins that accounts for three quarters of the dry weight skin in humans. Collagen containing a range of proteins has been reported for tissue engineering applications, but, only a small number of studies related to chemical structure evaluation of collagen are found in the literature. Collagen can be obtained from both the natural and synthetic sources and offers a wide range of biomedical applications due to its excellent biocompatibility and low immunogenicity. Hence, it is important to identify chemical structural properties of collagen and Fourier transform infrared (FTIR) appears to be a technique of choice to study their chemical structure. This review aims to highlight the use of FTIR to study collagen-based biomaterials, using it for characterization of collagen extracted from various sources. Characterization of collagen-based materials used in wound healing, skin substitutes, derma fillers, and aging of skin, collagen containing drug delivery agents, collagen-based materials used in tissue engineering, bone regeneration, and osteogenic differentiation is discussed in detail. FTIR analysis of collagen-containing materials used for dental applications, cleft-palate, and in alveolar-ridge preservation has also been highlighted. 相似文献
18.
Polycrystalline samples of BaTi1?x (Mn0.5Nb0.5) x O3 with x = 0.025, 0.05, 0.075, 0.1, 0.125, 0.15, and 0.175 have been synthesized by the high-temperature solid-state reaction technique. The effects of cationic substitution of manganese and niobium for titanium at B sites of the BaTiO3 perovskite lattice on symmetry and dielectric properties were investigated. X-ray diffraction at room temperature and dielectric permittivity in the temperature range from 85 K to 500 K and frequency range from 100 Hz to 2 × 105 Hz were studied. The evolution from a normal ferroelectric to a relaxor ferroelectric is emphasized. T C or T m decreases when both manganese and niobium are introduced into the lattice of BaTiO3. High dielectric constant of around 9000 at T C = 280 K was found for Ba Ti0.925(Mn0.5Nb0.5)0.075O3 ceramic. A relaxor ferroelectric with ΔT m = 60 K and $ \varepsilon_{\rm{r}}^{\prime } $ of about 3500 at 10 kHz with T m = 150 K was found for the BaTi0.85(Mn0.5Nb0.5)0.15O3 sample. 相似文献
19.
Imran SadiqImran Khan Faiza AenM.U. Islam M.U. Rana 《Physica B: Condensed Matter》2012,407(8):1256-1261
A series of single phase W-type Sr3−xCexFe16O27 (x=0, 0.02, 0.04, 0.06, 0.08, 0.10) hexagonal ferrites prepared by the Sol-Gel method was sintered at 1050 °C for 5 h. The X-ray diffraction analysis reveals that all the samples belong to the family of W-type hexagonal ferrites. The c/a ratio falls in the range of W-type hexagonal ferrites. The grain size was measured by SEM varies from 0.7684 to 0.4366 μm which shows that the Ce3+ substituted samples have smaller grain size than pure ferrite Sr3Fe16O27 which results from the difference in ionic radii of Ce3+ (1.034 Å) and Sr2+ (1.12 Å). The room temperature resistivity of the present samples varies from 6.5×108 to 272×108 Ω-cm. The coercivity increases from 1370 to 1993 Oe which is consistent with the decrease in grain size. The coercivity values indicate that the present samples fall in the range of hard ferrites. The large value of Hc may be due to domain wall pinning at the grain boundaries. 相似文献
20.
Aymn E. Rashad Ahmed H. Shamroukh Mohamed A. Ali Faiza M. Abdel‐Motti 《Heteroatom Chemistry》2007,18(3):274-282
Some novel cyclic and acyclic pyridazine and triazolopyridazine nucleoside derivatives were prepared. Some of the prepared products were selected and tested for antiviral activity against herpes simplex virus type‐1 (HSV‐1) and hepatitis‐A virus (HAV, MBB‐cell culture adapted strain). Plaque reduction infectivity assay was used to determine virus count reduction as a result of treatment with test compounds. Compound 15 showed the highest effect on the HAV than the other tested compounds. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:274–282, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20296 相似文献