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761.
Nanostructured ZnO photoelectrodes were synthesized on SnO2:F (FTO) glass substrate coated with sol–gel based ZnO seed layer via hydrothermal route at various deposition times: 30, 60, 90 and 180 min. Ruthenium based dye and carbon counter electrode were used for the fabrication of dye-sensitized solar cells (DSCs). Interestingly, nanolipsticks structures were found with low deposition times, where two dissimilar nanorods (111 and 165 nm) attached together. The number of nanolipsticks structures decreased and nanorods increased with increase of deposition time. The DSCs based on ZnO nanorods for 180 min, shows the maximum efficiency, 1.04% at 100 mW/cm2 light intensity. 相似文献
762.
F. Ceyda Dudak İsmail H. Boyacı Agnese Jurkevica Mahmud Hossain Zoraida Aquilar H. Brian Halsall Carl J. Seliskar William R. Heineman 《Analytical and bioanalytical chemistry》2009,393(3):949-956
A rapid and convenient assay system was developed to detect viable Escherichia coli in water. The target bacteria were recovered from solution by immunomagnetic separation and incubated in tryptic soy broth
with isopropyl-β-d-thiogalactopyranoside, which induces formation of β-galactosidase in viable bacteria. Lysozyme was used to lyse E. coli cells and release the β-galactosidase. β-Galactosidase converted 4-methylumbelliferyl-β-d-galactoside to 4-methylumbelliferone (4-MU), which was measured by fluorescence spectrophotometry using excitation and emission
wavelengths of 355 and 460 nm, respectively. Calibration graphs of 4-MU fluorescence intensity versus E. coli concentration showed a detection range between 8 × 104 and 1.6 × 107 cfu mL−1, with a total analysis time of less than 3 h. The advantage of this method is that it detects viable cells because it is
based on the activity of the enzyme intrinsic to live E. coli. 相似文献
763.
Mohammad Kamal Hossain Yasutaka Kitahama Genin Gary Huang Xiaoxia Han Yukihiro Ozaki 《Analytical and bioanalytical chemistry》2009,394(7):1747-1760
Surface-enhanced Raman scattering (SERS) enhancement and the reproducibility of the SERS signal strongly reflect the quality
and nature of the SERS substrates because of diverse localized surface plasmon resonance (LSPR) excitations excited at interstitials
or sharp edges. LSPR excitations are the most important ingredients for achieving huge enhancements in the SERS process. In
this report, we introduce several gold and silver nanoparticle-based SERS-active substrates developed solely by us and use
these substrates to investigate the influence of LSPR excitations on SERS. SERS-active gold substrates were fabricated by
immobilizing colloidal gold nanoparticles on glass slides without using any surfactants or electrolytes, whereas most of the
SERS-active substrates that use colloidal gold/silver nanoparticles are not free of surfactant. Isolated aggregates, chain-like
elongated aggregates and two-dimensional (2D) nanostructures were found to consist mostly of monolayers rather than agglomerations.
With reference to correlated LSPR and SERS, combined experiments were carried out on a single platform at the same spatial
position. The isolated aggregates mostly show a broadened and shifted SPR peak, whereas a weak blue-shifted peak is observed
near 430 nm in addition to broadened peaks centered at 635 and 720 nm in the red spectral region in the chain-like elongated
aggregates. In the case of 2D nanostructures, several SPR peaks are observed in diverse frequency regions. The characteristics
of LSPR and SERS for the same gold nanoaggregates lead to a good correlation between SPR and SERS images. The elongated gold
nanostructures show a higher enhancement of the Raman signal than the the isolated and 2D samples. In the case of SERS-active
silver substrates for protein detection, a new approach has been adopted, in contrast to the conventional fabrication method.
Colloidal silver nanoparticles are immobilized on the protein functionalized glass slides, and further SERS measurements are
carried out based on LSPR excitations. A new strategy for the detection of biomolecules, particularly glutathione, under aqueous
conditions is proposed. Finally, supramolecular J-aggregates of ionic dyes incorporated with silver colloidal aggregates are
characterized by SERS measurements and correlated to finite-difference time-domain analysis with reference to LSPR excitations.
Figure SPR and SERS images for isolated, elongated and two-dimensional gold nanostructures 相似文献
764.
In this paper, double integrals over an arbitrary quadrilateral are evaluated exploiting finite element method. The physical region is transformed into a standard quadrilateral finite element using the basis functions in local space. Then the standard quadrilateral is subdivided into two triangles, and each triangle is further discretized into 4 × n2 right isosceles triangles, with area , and thus composite numerical integration is employed. In addition, the affine transformation over each discretized triangle and the use of linearity property of integrals are applied. Finally, each isosceles triangle is transformed into a 2-square finite element to compute new n2 extended symmetric Gauss points and corresponding weight coefficients, where n is the lower order conventional Gauss Legendre quadratures. These new Gauss points and weights are used to compute the double integral. Examples are considered over an arbitrary domain, and rational and irrational integrals which can not be evaluated analytically. 相似文献
765.
Rubber-like materials can deform largely and non-linearly upon loading and return to the initial configuration when the load is removed. Such rubber elasticity is achieved due to very flexible long chain molecules and a three-dimensional network structure that is formed via cross-linking or entanglements between molecules. Over the years, to model the mechanical behaviour of such randomly-oriented micro-structure, several phenomenological and micro-mechanically motivated network models for nearly incompressible hyperelastic polymeric materials have been proposed in the literature. For comparison of all selected models in reproducing the well-known Treloar data, the analytical expressions for the three homogeneous defomation modes, i.e. uniaxial tension, equibiaxial tension and pure shear have been derived and the performances of the models are analysed. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
766.
767.
In this paper, we present a theoretical calculation of a highly nonlinear germanium (Ge) doped photonic crystal fiber with all-normal group velocity dispersion to design a supercontinuum (SC) light source at 1.55 μm. By doping 3% higher refractive index Ge inside the host silica, the nonlinear coefficient is increased to a value as large as 60.5 W?1 km?1 at 1.55 μm. A 10 dB bandwidth of a 120 nm SC spectrum for a 2.5 ps input optical pulse and a 10 dB bandwidth of a 190 nm SC spectrum for a 1.0 ps input optical pulse have been found using the same fiber length of 200m and input optical power of 18 W. The coherent lengths of the generated SC light sources are found to be 8.8 μm for a 2.5 ps input optical pulse and 5.6 μm for a 1.0 ps input optical pulse. Therefore, the highest longitudinal resolution at 1.55 μm is found to be about 4.0 μm for biological tissues. 相似文献
768.
M.A. Hossain M.S. Ali A.K.M.A. Islam 《The European Physical Journal B - Condensed Matter and Complex Systems》2012,85(12):1-7
Conversations allow the quick transfer of short bits of information and it is reasonable to expect that changes in communication medium affect how we converse. Using conversations in works of fiction and in an online social networking platform, we show that the utterance length of conversations is slowly shortening with time but adapts more strongly to the constraints of the communication medium. This indicates that the introduction of any new medium of communication can affect the way natural language evolves. 相似文献
769.
Shishir Ghosh Shariff E. Kabir Farzana K. Camellia Md. Kamal Hossain Daniel T. Haworth Sergey V. Lindeman Tasneem A. Siddiquee Dennis W. Bennett 《Journal of chemical crystallography》2010,40(8):712-715
Abstract
Treatment of [Mo(CO)3(NCMe)3] with bis(diphenylphosphino)methane (dppm) and triphenylphosphine (PPh3) at 50 °C afforded mer-[Mo(CO)3(PPh3)(κ 2-dppm)] (1) in 55% yield which has been characterized by single crystal X-ray diffraction studies and spectroscopic measurements. Compound 1 crystallizes in the triclinic space group P−1 with a = 10.3449(6), b = 11.1570(6), c = 17.8961(10) ?, β = 80.8400(10)°, Z = 2 and V = 1959.8(2) ?3. 相似文献770.
Jagjit Singh Dhaliwal Said Moshawih Khang Wen Goh Mei Jun Loy Md. Sanower Hossain Andi Hermansyah Vijay Kotra Nurolaini Kifli Hui Poh Goh Sachinjeet Kaur Sodhi Dhaliwal Hayati Yassin Long Chiau Ming 《Molecules (Basel, Switzerland)》2022,27(20)
Chalcones have been well examined in the extant literature and demonstrated antibacterial, antifungal, anti-inflammatory, and anticancer properties. A detailed evaluation of the purported health benefits of chalcone and its derivatives, including molecular mechanisms of pharmacological activities, can be further explored. Therefore, this review aimed to describe the main characteristics of chalcone and its derivatives, including their method synthesis and pharmacotherapeutics applications with molecular mechanisms. The presence of the reactive α,β-unsaturated system in the chalcone’s rings showed different potential pharmacological properties, including inhibitory activity on enzymes, anticancer, anti-inflammatory, antibacterial, antifungal, antimalarial, antiprotozoal, and anti-filarial activity. Changing the structure by adding substituent groups to the aromatic ring can increase potency, reduce toxicity, and broaden pharmacological action. This report also summarized the potential health benefits of chalcone derivatives, particularly antimicrobial activity. We found that several chalcone compounds can inhibit diverse targets of antibiotic-resistance development pathways; therefore, they overcome resistance, and bacteria become susceptible to antibacterial compounds. A few chalcone compounds were more active than conventional antibiotics, like vancomycin and tetracycline. On another note, a series of pyran-fused chalcones and trichalcones can block the NF-B signaling complement system implicated in inflammation, and several compounds demonstrated more potent lipoxygenase inhibition than NSAIDs, such as indomethacin. This report integrated discussion from the domains of medicinal chemistry, organic synthesis, and diverse pharmacological applications, particularly for the development of new anti-infective agents that could be a useful reference for pharmaceutical scientists. 相似文献