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101.
Base-catalyzed one-pot cyclocondensation reactions of acryloyl and cinnamoyl chlorides with β-nitroenamine derivatives have been performed under mild conditions and target 7-substituted thiazolo-[3,2-a] or imidazolo-[1,2-a]pyridin-5-one derivatives were prepared successfully in moderate to good yields. The cyclization reactions may proceed via Michael addition followed by iminoketene-amide tautomerization in view of the products formed. 相似文献
102.
Erdinc Doganci Mesut Gorur Cavit Uyanik Faruk Yilmaz 《Journal of polymer science. Part A, Polymer chemistry》2014,52(23):3390-3399
Well‐defined AB3‐type miktoarm star‐shaped polymers with cholic acid (CA) core were fabricated with a combination of “click” chemistry and ring opening polymerization (ROP) methods. Firstly, azide end‐functional poly(ethylene glycol) (mPEG), poly(methyl methacrylate) (PMMA), polystyrene (PS), and poly(ε‐caprolactone) (PCL) polymers were prepared via controlled polymerization and chemical modification methods. Then, CA moieties containing three OH groups were introduced to these polymers as the end groups via Cu(I)‐catalyzed click reaction between azide end‐functional groups of the polymers ( mPEG‐N3 , PMMA‐N3 , PS‐N3 , and PCL‐N3 ) and ethynyl‐functional CA under ambient conditions, yielding CA end‐functional polymers ( mPEG‐Cholic , PMMA‐Cholic , PS‐Cholic , and PCL‐Cholic ). Finally, the obtained CA end‐capped polymers were employed as the macroinitiators in the ROP of ε‐caprolactone (ε‐CL) yielding AB3‐type miktoarm star polymers ( mPEG‐Cholic‐PCL3 , PMMA‐Cholic‐PCL3 , and PS‐Cholic‐PCL3 ) and asymmetric star polymer [ Cholic‐(PCL)4 ]. The chemical structures of the obtained intermediates and polymers were confirmed via Fourier transform infrared and 1H nuclear magnetic resonance spectroscopic techniques. Thermal decomposition behaviors and phase transitions were studied in detail using thermogravimetric analysis and differential scanning calorimetry experiments. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3390–3399 相似文献
103.
A biosensor based on conductive poly(pyrrole‐co‐pyrrole‐2‐carboxylic acid) [Poly(Py‐co‐PyCOOH)] copolymer film coated gold electrode was developed for the quantitative phosphate determination. Enzyme pyruvate oxidase was immobilized chemically via the functional carboxylated groups of the copolymer. The potential to be applied which is deficiency of phosphate biosensor studies for precise phosphate detection was clarified by using differential pulse voltammetry technique. Performance of the sensing ability of the biosensor was improved by optimizing cofactor/cosubstrate concentrations, polymeric film density and pH. The biosensor showed a linearity up to phosphate concentration of 5 mM, operational stability with a relative standard deviation (RSD) of 0.07 % (n=7) and accuracy of 101 % at ?0.15 V (vs. Ag/AgCl). Detection limit (LOD) and sensitivity were calculated to be 13.3 μM and 5.4 μA mM?1 cm?2, respectively by preserving 50 % of its initial response at the end of 30 days. It's performance was tested to determine phosphate concentrations in two streams of Zonguldak City in Turkey. Accuracy of phosphate measurement in stream water was found to be 91 %. 相似文献
104.
Carmen Vogt Muhammet S. Toprak Mamoun Muhammed Sophie Laurent Jean-Luc Bridot Robert N. Müller 《Journal of nanoparticle research》2010,12(4):1137-1147
Obtaining small (<50 nm), monodispersed, well-separated, single iron oxide core–silica (SiO2) shell nanoparticles for biomedical applications is still a challenge. Preferably, they are synthesised by inverse microemulsion
method. However, substantial amount of aggregated and multicore core–shell nanoparticles is the undesired outcome of the method.
In this study, we report on the production of less than 50 nm overall size, monodispersed, free of necking, single core iron
oxide–SiO2 shell nanoparticles with tuneable shell thickness by a carefully optimized inverse microemulsion method. The high degree
of control over the process is achieved by understanding the mechanism of core–shell nanoparticles formation. By varying the
reaction time and precursor concentration, the thickness of silica layer on the core nanoparticles can be finely adjusted
from 5 to 13 nm. Residual reactions during the workup were inhibited by a combination of pH control with shock freezing and
ultracentrifuging. These high-quality tuneable core–shell nanocomposite particles exhibit superparamagnetic character and
sufficiently high magnetization with great potential for biomedical applications (e.g. MRI, cell separation and magnetically
driven drug delivery systems) either as-prepared or by additional surface modification for improved biocompatibility. 相似文献
105.
Muhammet Samet Kilic 《Electroanalysis》2021,33(8):1963-1977
A biosensor for phosphate determination with the flow-injection system was developed using rhodium nanoparticles modified Poly(pyrrole-co-[1-(2-aminophenyl) pyrrole])/pyruvate oxidase. The biosensor showed a very wide linearity up to 70 mM phosphate concentration compared to previously reports, response time of 4 s., operational stability with a relative standard deviation of 0.009 % and accuracy of 99.4 %±0.949 at a flow rate of 2.0 Ml min.−1 at exactly −0.68 V. Detection limit were calculated to be 21±0.001 μM by preserving 81.1 % of its initial response at the end of 16th days. Artificial urine was analyzed without dilution to investigate biosensor performance. 相似文献
106.
In this work, determination of selenium in various water samples was done by using hydride generation atomic absorption spectrometry. The most appropriate values of HCl concentration, NaBH4 concentration, NaOH concentration, flow rate of argon and flow rate of waste solution were determined. The optimum concentration of the HCl, NaBH4 and NaOH solutions were found to be 7.0 mol L?1, 1.0% and 0.75%, respectively. The optimum flow rate of Ar gas and waste solution were also found to be 100.9 mL min?1 and 4.0 mL min?1, respectively. Values of LOD and LOQ were calculated separately for total Se and Se(IV). LOD and LOQ values were calculated 0.56 μg L?1, 1.87 μg L?1 for total Se and 0.72 μg L?1, 2.40 μg L?1 for Se(IV), respectively. The precision was evaluated by relative standard deviation (RSD%) was found to be 3.5% for total Se and 3.1% for Se(IV) (n = 11). A standard reference material (NIST 1643e) was used in order to check the accuracy of the proposed method. There was a good agreement between certified and found values for standard reference material. The method was applied to the analysis of total Se and Se(IV) concentrations in tap water samples collected from the various regions of Mu?la. Proposed method showed spike recovery ranges from 92% to 116% in water samples. 相似文献
107.
Veli Shakhmurov Muhammet Kurulay 《Numerical Methods for Partial Differential Equations》2023,39(2):923-931
The Lp-coercive properties of a nonlocal fractional elliptic equation is studied. Particularly, it is proved that the fractional elliptic operator generated by this equation is sectorial in Lp space and also is a generator of an analytic semigroup. Moreover, by using the Lp-separability properties of the given elliptic operator the maximal regularity of the corresponding nonlocal fractional parabolic equation is established. 相似文献
108.
109.
Sinem Sipahioglu Kara Mustafa Yasin Ate Gozde Deveci Ahmet Cetinkaya Muhammet U. Kahveci 《Journal of polymer science. Part A, Polymer chemistry》2019,57(6):673-680
Tetrazine mediated inverse Electron Demand Diels–Alder Reaction (IEDDA) is an important modification technique due to its high selectivity and super‐fast kinetics. Incorporation of tetrazine moieties on polymer chains requires multistep synthetic pathways and a post‐polymerization step leading to functional polymeric materials. Such approaches involve separate syntheses of polymer and the molecule which will be employed in modification. Herein, we introduce a straightforward synthetic approach for direct synthesis of tetrazine groups on polymers as side chains. As model systems, tetrazine functional poly(N‐isopropylacrylamide)‐and poly(ethylene glycol)‐based polymers from corresponding precursor polymers with nitrile moieties as pendant groups are prepared and IEDDA Click Reaction is achieved with trans‐cyclooctene derivatives. The click reaction is monitored by both NMR and UV–vis spectroscopies. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 673–680 相似文献
110.
By using Mn2+ and Mn3+ salts, and freshly extracted ovalbumin, Mn3O4 nanocrystals have been synthesized successfully. The X-ray diffraction results indicated that the synthesized nanoparticles have only the spinel structure without the presence of any other phase impurities. As the ovalbumin–water mixture was highly basic, the process did not require any use of base to increase the pH where hydrolysis took place. A gel formed where water soluble ovalbumin proteins served as a perfect matrix for entrapment of metal ions (Mn2+ and Mn3+). Upon heat treatment, the dried gel precursor decomposed into nanocrystalline Mn3O4. The discrepancy between the crystallite size from XRD and particle size SEM analysis reveals polycrystalline nature of the synthesized particles with this route. EPR analysis of Mn3O4 shows a narrow and symmetric line indicating the absence of hyperfine splitting. 相似文献