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121.
Kadir Erol 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(10):629-635
The separation and purification of important biomolecule deoxyribonucleic acid (DNA) molecules are extremely important. The adsorption technique among these methods is highly preferred as the adsorbent cryogels are pretty much used due to large pores and the associated flow channels. In this study, the adsorption of DNA via Co(II) immobilized poly(2-hydroxyethyl methacrylate-glycidyl methacrylate) [poly(HEMA-GMA)] cryogels was performed under varying conditions of pH, interaction time, initial DNA concentration, temperature, and ionic strength. For the characterization of cryogels; swelling test, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), surface area (BET), elemental and ICP-OES analysis were performed. L-lysine amino acid was chosen as Co(II)-chelating agent and the adsorption capacity of cryogels was determined as 33.81 mg DNA/g cryogel. Adsorption of pea DNA was studied under the optimum adsorption conditions and DNA adsorption capacity of cryogels was found as 10.14 mg DNA/g cryogel. The adsorption process was examined via Langmuir and Freundlich isotherm models and the Langmuir adsorption model was determined to be more appropriate for the DNA adsorption onto cryogels. 相似文献
122.
A novel poly(acrylic acid)‐iron rich smectite (IRS) superabsorbent composite was synthesized by graft copolymerization reaction of acrylic acid (AA) in the presence of N,N‐methylenebisacrylamide (MBA) as a crosslinker. IRS was used to strengthen the hydrogel products in the polymerization process. Water absorbencies for these superabsorbent composites in water and saline solutions were investigated. IRS caused a reduced equilibrium swelling as low as 8–26%. However, grafted IRS particles resulted in improved gel strength as high as 66% compared to the IRS‐free sample. IRS modified superabsorbent hydrogel composites exhibited higher thermal stability compared to the IRS‐free sample. The pH dependent reversible swelling behavior of hydrogels was also investigated. It is found that the swelling process is pH dependent and reversible for synthesized superabsorbent. Superabsorbent hydrogel composites were characterized by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). FTIR spectroscopy was confirmed grafting of acrylic chains onto the surface of IRS particles. From the standpoint of these results, these strengthened and thermostabilized hydrogels may be considered as good candidates for a controlled release study and agricultural applications. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
123.
Yasemin Arslan Udum Kadir Pekmez Attila Yıldız 《Journal of Solid State Electrochemistry》2006,10(2):110-116
The copolymer films of sulfonated aniline and sulfonated 3-methyl thiophene were synthesized by electrochemical polymerization.
The sulfonated copolymer films have better solubility in DMSO and KOH than the corresponding homopolymers. The conductivity
of the copolymer films increase with the increase in the number of thiophene rings in the polymeric backbone. Copolymer films
synthesized were investigated by cyclic voltammetry, UV-visible and FT-IR spectroscopy, dry conductivity and intrinsic viscosity
measurements and elemental analysis. The elemental analysis and UV-visible spectroscopic results show that copolymer films
have properties intermediate between the two homopolymers. 相似文献
124.
Diazomethyl ketones (2-diazoethanones) were reacted with the Vilsmeier reagent ((chloromethylidene)dimethylammonium chloride) to yield α-diazo-β-oxoaldehydes and chloromethyl ketones. 2′,4′-Dimethoxy-α-diazoacetophenone gave 2-chloro-1-(2,4-dimethoxyphenyl)-3-(dimethylamino)prop-2-en-1-one ( 5 ) in addition to the expected products. Phenyldiazomethanes gave the corresponding benzyl chlorides but not the (phenyl)diazoacetaldehydes even at temperatures as low as ?60°. The diazo-transfer reactions of phenylacetaldehydes and 2-azido-1-ethylpyridin-1-ium tetrafluoroborate also did not yield the expected(phenyl)diazoacetaldehydes. 相似文献
125.
The first observation of Metal-Enhanced Fluorescence (MEF) from large gold colloids is presented. Gold colloids, 40 and 200 nm
diameter, were deposited onto glass substrates in a homogeneous fashion. The angular-dependent fluorescence emission of FITC-HSA,
adsorbed onto gold colloids, was measured on a rotating stage which was used to evaluate MEF at all spatial angles. The emission
intensity of FITC-HSA was found to be up to 2.5-fold brighter than the emission on bare glass substrates at an angle of 270
degrees. This is explained by the Radiating Plasmon Model, whereby the combined system, composed of the fluorophore and the
metal colloids, emits with the photophysical characteristics of the fluorophore, after the excitation and the partial radiationless
energy transfer between the excited states of the fluorophore and the surface plasmons of the gold colloids. The fluorescence
enhancement was found to be higher with 200 nm gold colloids as compared to 40 nm colloids due to the increased contribution
of the scattering portion of the 200 nm gold colloid extinction spectrum. These observations suggest that gold colloids could
be used in MEF applications, offering more stable surfaces than the commonly used silvered surfaces, for applications requiring
longer term storage and use. 相似文献
126.
In this paper, we describe an optical geometry that facilitates our further characterization of the temperature changes above
silver island films (SiFs) on sapphire plates, when exposed to microwave radiation. Since sapphire transmits IR, we designed
an optical scheme to capture real-time temperature images of a thin water film on sapphire plates with and without SiFs during
the application of a short microwave pulse. Using this optical scheme, we can accurately determine the temperature profile
of solvents in proximity to metal structures when exposed to microwave irradiation. We believe that this optical scheme will
provide us with a basis for further studies in designing metal structures to further improve plasmonic-fluorescence clinical
sensing applications, such as those used in microwave accelerated metal-enhanced fluorescence (MAMEF). 相似文献
127.
In this Rapid Communication, we present the development of monodisperse core-shell (silver core-silica shell) nanoparticles
with various shell thicknesses featuring a fluorophore, subsequently named Metal-Enhanced Fluorescence (MEF) nanoballs. MEF
nanoballs consist of a ≈130 nm silver nanoparticle core, a silica shell with up to 35 nm thickness and fluorophores doped within the silica shell.
Fluorescent nanobubbles where the silver core is removed by chemical etching are used as control samples to show the benefits
of using silver nanoparticles, i.e, Metal-Enhanced Fluorescence. Finally, we demonstrate the broad potential biological applications
of MEF nanoballs by employing near-infra red emitting probes (Rhodamine 800) within the silica shell, for potential applications
in cellular imaging and solution-based sensing.
Kadir Aslan, Meng Wu, Contributed equally 相似文献
128.
Ahmet Şener İshak Bildirici İsrafil Tozlu Hasan Genç Kadir Arısoy 《Journal of heterocyclic chemistry》2007,44(5):1077-1081
1,5‐Diphenyl‐1H‐pyrazole‐3,4‐dicarboxylic acid‐4‐ethyl ester 2 , obtained from the 4‐ethoxycarbonyl‐5‐phenyl‐2,3‐furandione 1 and N‐benzylidene‐N′‐phenyl hydrazine, was converted via reactions of its acid chloride 3 with various alcohols or N‐nucleophiles into the corresponding ester 5 or amide derivatives 6 , respectively. In addition, 2 was decarboxylated to give ethyl 1,5‐diphenylpyrazole‐4‐carboxylate 4 . Nitrile 7 derivative of 2 was also obtained by dehydration of 6a in a mixture of SOCl2 and DMF. While cyclocondensation reaction of 2 with hydrazine hydrate leads to the formation of pyrazolo[3,4‐d]pyridazine‐4,7‐dione 8 , the reaction of 3 with anhydrous hydrazine provided a new bis pyrazole derivative 9 . 相似文献
129.
In this paper, we investigated the effects of low-power microwave heating on the components of the recently described new approach to surface DNA hybridization assays, based on the Microwave-Accelerated Metal-Enhanced Fluorescence (MAMEF) platform technology. Thiolated oligonucleotides have been linked to surface-bound silver nanostructures which partially coat a glass slide. The addition of a complementary fluorescein-labeled oligonucleotide results in metal-enhanced fluorescein emission as the probe is brought into close proximity to the silver upon hybridization. In addition, the combined use with low-power microwave heating, which is thought to locally heat around the silvered surface, affords for both the assay kinetics and optical amplification to also be localized to the surface. In our model DNA target assay reported here, we can detect 23-mer targets in less than 20 s, up to a 600-fold decrease in the assay run time as compared to control samples hybridized to completion at room temperature. Importantly, the use of MAMEF also reduces the extent of unwanted non-specific DNA absorption, further increasing specific DNA target detection limits. It was also found that low-power microwave heating did not denature DNA and the bulk temperature increase near to silver nanoparticles was only ca. 1 degrees C. 相似文献
130.
Roscioli JR Hammer NI Johnson MA Diri K Jordan KD 《The Journal of chemical physics》2008,128(10):104314
We report a combined photoelectron and vibrational spectroscopy study of the (H(2)O)(7)(-) cluster anions in order to correlate structural changes with the observed differences in electron binding energies of the various isomers. Photoelectron spectra of the (H(2)O)(7)(-) . Ar(m) clusters are obtained over the range of m=0-10. These spectra reveal the formation of a new isomer (I') for m>5, the electron binding energy of which is about 0.15 eV higher than that of the type I form previously reported to be the highest binding energy species [Coe et al., J. Chem. Phys. 92, 3980 (1990)]. Isomer-selective vibrational predissociation spectra are obtained using both the Ar dependence of the isomer distribution and photochemical depopulation of the more weakly (electron) binding isomers. The likely structures of the isomers at play are identified with the aid of electronic structure calculations, and the electron binding energies, as well as harmonic vibrational spectra, are calculated for 28 low-lying forms for comparison with the experimental results. The HOH bending spectrum of the low binding type II form is dominated by a band that is moderately redshifted relative to the bending origin of the bare water molecule. Calculations trace this feature primarily to the bending vibration localized on a water molecule in which a dangling H atom points toward the electron cloud. Both higher binding forms (I and I') display the characteristic patterns in the bending and OH stretching regions signaling electron attachment primarily to a water molecule in an AA binding site, a persistent motif found in non-isomer-selective spectra of the clusters up to (H(2)O)(50)(-). 相似文献