排序方式: 共有28条查询结果,搜索用时 15 毫秒
1.
Mahmoudi M Amiri H Shokrgozar MA Sasanpour P Rashidian B Laurent S Casula MF Lascialfari A 《Chemical communications (Cambridge, England)》2011,47(37):10404-10406
The creation of novel engineered multimodal nanoparticles (NPs) is a key focus in bionanotechnology and can lead to deep understanding of biological processes at the molecular level. Here, we present a multi-component system made of gold-coupled core-shell SPIONs, as a new nanoprobe with signal enhancement in surface Raman spectroscopy, due to its jagged-shaped gold shell coating. 相似文献
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Ali Bagheri Bizhan Honarvar Amin Azdarpour 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2020,26(5):453-480
ABSTRACT The present study mainly focuses on enhancing the performance of solar still unit using solar energy through cylindrical parabolic collector and solar panels. A 300 W solar panel is used to heat saline water by thermal elements outside the solar still unit. Solar panels are cooled during the hot hours of the day; thus, reducing their temperature may lead to an increase in solar panel efficiency followed by an increase in the efficiency of the solar still unit. The maximum amount of freshwater used in the experiment was 2.132 kg/day. The experiments were modelled using ANNs. Based on neural network simulation results, there is a significant correlation between experimental data and neural network modelling. This paper compares experimental data with data obtained from mathematical modelling and ANNs. As a conclusion, the artificial neural network prediction has been more accurate than the simplified first principles model presented. 相似文献
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Ghasem Rashidian Sara Bahrami Gorji Mehdi Naderi Farsani Marko D. Prokić 《Natural product research》2020,34(17):2413-2423
AbstractMedicinal plants play an important role in aquaculture as feed additives. This study aimed to investigate effects of alcoholic extract of acorn on growth performance, body composition, digestive enzymes activity and blood biochemical parameters of rainbow trout (O. mykiss) as a commercially important fish. Five dietary treatments were supplemented: 100, 200, 400 and 600?mg.kg?1 of the extract. Fishes were fed twice per day for 8?weeks, and results showed that acorn extract positively affected all investigated parameters in rainbow trout fishes. Digestive enzymes activity and growth performance were increased, while activity of liver enzymes and cortisol were lowed in comparison to control individuals. Body composition of treated animals was also enhanced. Comparison between treated groups together with integrative biomarker response (IBR) values indicated greatest effects in animals fed with 400 and 600?mg.kg?1 of the extract. Positive effects of the acorn represent promising start point for further studies. 相似文献
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Rashidian M Song JM Pricer RE Distefano MD 《Journal of the American Chemical Society》2012,134(20):8455-8467
Site-specific chemical modification of proteins is important for many applications in biology and biotechnology. Recently, our laboratory and others have exploited the high specificity of the enzyme protein farnesyltransferase (PFTase) to site-specifically modify proteins through the use of alternative substrates that incorporate bioorthogonal functionality including azides and alkynes. In this study, we evaluate two aldehyde-containing molecules as substrates for PFTase and as reactants in both oxime and hydrazone formation. Using green fluorescent protein (GFP) as a model system, we demonstrate that the purified protein can be enzymatically modified with either analogue to yield aldehyde-functionalized proteins. Oxime or hydrazone formation was then employed to immobilize, fluorescently label, or PEGylate the resulting aldehyde-containing proteins. Immobilization via hydrazone formation was also shown to be reversible via transoximization with a fluorescent alkoxyamine. After characterizing this labeling strategy using pure protein, the specificity of the enzymatic process was used to selectively label GFP present in crude E. coli extract followed by capture of the aldehyde-modified protein using hydrazide-agarose. Subsequent incubation of the immobilized protein using a fluorescently labeled or PEGylated alkoxyamine resulted in the release of pure GFP containing the desired site-specific covalent modifications. This procedure was also employed to produce PEGylated glucose-dependent insulinotropic polypeptide (GIP), a protein with potential therapeutic activity for diabetes. Given the specificity of the PFTase-catalyzed reaction coupled with the ability to introduce a CAAX-box recognition sequence onto almost any protein, this method shows great potential as a general approach for selective immobilization and labeling of recombinant proteins present in crude cellular extract without prior purification. Beyond generating site-specifically modified proteins, this approach for polypeptide modification could be particularly useful for large-scale production of protein conjugates for therapeutic or industrial applications. 相似文献
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Rashidian M Dozier JK Lenevich S Distefano MD 《Chemical communications (Cambridge, England)》2010,46(47):8998-9000
An aldehyde-containing alternative substrate for protein farnesyltransferase was prepared and shown to be enzymatically incorporated into a peptide and a protein. The protein was subsequently immobilized onto aminooxy-functionalized agarose beads or labeled with a fluorophore. This method for protein modification provides an alternative to the commonly employed Cu(I)-catalyzed click reaction. 相似文献
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Bizhan Malaekeh-Nikouei Sayyed A. Sajadi Tabassi Golara Gerayeli Mehran Arab Salmani Ali Gholamzadeh 《Journal of inclusion phenomena and macrocyclic chemistry》2012,72(3-4):383-387
The aim of present study was to evaluate the effect of natural, synthetic cyclodextrins (CDs) and CD mixtures on aqueous solubility of beclomethasone dipropionate (BDP). The phase solubility studies were done in the presence of 6 CDs. Furthermore, aqueous solubility of BDP was tested in the presence of CD mixtures. The solubility of BDP in water was increased by 30, 77, 155 and 30 folds in the solution containing 20%?w/v α-CD, hydroxylpropyl β-CD (HP-β-CD), hydroxypropyl γ-CD (HP-γ-CD) and sulphobutylether β-CD (SBE-β-CD), respectively. CD mixtures had remarkable effect on the aqueous solubility of BDP so that solubility in water increased between 200 and 1,500 times in the presence of different CD mixtures. Further addition of sodium acetate to the solubilisation medium reduced the aqueous solubility. In conclusion, CD complexation was able to improve the aqueous solubility of BDP. The synergistic effect of cyclodextrin mixture was observed. 相似文献
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A simple and efficient transmission line model is proposed here to study how the transmission characteristics of photonic crystal waveguides are tailored by introduction of stubs patterned in the photonic crystal lattice. It is shown that band-pass and band-stop optical filters can be easily designed and optimized when stubs of appropriate length are brought in. Since the lengths of the designed stubs are not necessarily integer multiples of the photonic crystal lattice constant, a geometric shift in a portion of the photonic crystal structure is shown to be essential. The proposed model is verified by using a rigorous numerical method. An excellent agreement is observed between the numerical results and the transmission characteristics as extracted by the proposed model. 相似文献
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Malaekeh-Nikouei B Jaafari MR Tabassi SA Samiei A 《Colloids and surfaces. B, Biointerfaces》2008,67(2):238-244
The aim of this study was to prepare and characterize neutral, positively charged, negatively charged and fusogenic liposomes of different sizes that contain cyclosporine A (CyA) and to evaluate their immunosuppressive activity on human T-cells. Neutral liposomes containing CyA were prepared from dipalmitoylphosphatidylcholine (DPPC) and cholesterol using the solvent evaporation method. To prepare positively charged, negatively charged and fusogenic liposomes containing CyA; stearylamine (SA), dicetylphosphate (DCP) and dioleoylphosphatidylethanolamine (DOPE) were added to the neutral liposome formulation, respectively. To reduce the size of liposomes containing CyA, extrusion through polycarbonate filters (1000, 400 and 100 nm) was used. The liposomes were characterized by their size, zeta potential and encapsulation efficiency. The in vitro immunosuppressive effects of an aqueous solution of CyA and different liposomes containing CyA were determined on human T-cells by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay. The mean diameter of the various multilamellar vesicle (MLV) liposomes containing CyA was between 1.76 and 2.49 μm. The encapsulation efficiency for the different MLV and extruded liposomes containing CyA ranged from 73% to 90%. In vitro immunosuppressive evaluation by T-cell culture showed that fusogenic liposomes have the best inhibitory effects on T-cell proliferation compared to the other liposomes. Reducing the size of the liposomes did not affect the in vitro immunosuppressive activity. The average IC50 for the aqueous solution of CyA and the neutral, positively charged, negatively charged and fusogenic liposomes containing CyA was 4.98 × 10−2, 7.38, 1.43, 3.84 × 10−3 and 7.93 × 10−5 mM, respectively. The results of this study indicate that fusogenic liposomes have the strongest immunosuppressive activity and could be considered as a suitable delivery system for CyA. 相似文献
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Nonlinear responses and optical limiting behavior of Basic Violet 16 dye under CW laser illumination
Nonlinear optical properties of Basic Violet 16 dye solution in water are studied employing different optical techniques. Experiments are performed using the second harmonic of a continuous Nd-Yag laser beam at 532 nm wavelength and 100 mW power. The effect of nonlinearity of Basic Violet 16 dye in broadening the laser beam is observed. The optical limiting behavior is investigated by measuring the transmission of the samples. The third-order nonlinearity, χ3 of Basic Violet 16 dye, is measured using Z-scan data. The nonlinear absorption coefficient is calculated using the open aperture Z-scan data, while its nonlinear refractive index is measured using the closed aperture Z-scan data. All experiments are done for different concentrations and thicknesses of Basic Violet 16 dye solution. The effect of intensity of input laser beam on the nonlinear susceptibility is studied experimentally. Results indicate that Basic Violet 16 dye is a potential candidate for low-power optical limiting applications. 相似文献