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951.
R. Mirzajani N. Pourreza S. Safar Ali Najjar 《Research on Chemical Intermediates》2014,40(8):2667-2679
In this work, β-CD-based polyurethane copolymers (β-CDPU) have been prepared by reacting β-CD with hexamethylene diisocyanate as cross-linked agent in dry DMF. This polymer showed high selectivity for preconcentration of Pb(II) at trace level prior to its flame atomic absorption spectrometric determination. The effect of several parameters such as pH, flow rate of sample, eluent kind and volume was investigated. The adsorption behaviors and mechanisms of Pb(II) on the samples were also studied. The maximum adsorption amount of Pb(II) was 8 mg g?1 with the preconcentration factor of 250 for Pb(II). The Langmuir isotherm was proved to describe the adsorption data better than the Freundlich isotherm and a pseudo-first-order kinetic model fits the adsorption kinetic processes well. The calibration curve was linear in the range of (3–200 ng mL?1) with a correlation coefficient of 0.9996. The limit of detection based on three times the standard deviation of the blank was 1.15 ng mL?1. The relative standard deviations for the determination of 10 and 100 ng mL?1 of Pb(II) were 3.60 and 0.43 % (n = 10), respectively. The method was successfully applied to the determination of lead in some environmental samples such as Tehran and Bushehr drinking water, river water and dust samples. 相似文献
952.
Fereshteh Rezaei Nahid Pirhady Tavandashti Ali Reza Zahedi 《Research on Chemical Intermediates》2014,40(3):1233-1247
Polyaniline nanofibers are readily synthesized by bulk polymerization; ammonium per sulphate (APS) is used as oxidizing agent and hydrochloric acid as dopant without any hard or soft templates. A detailed study was conducted on the effect of a variety of synthetic conditions on the size and morphology of the polyaniline nanostructure. These conditions include the concentration of dopant, and the APS-to-aniline and acid-to-aniline molar ratios. The morphology of the nanofibers was confirmed by SEM and TEM. XRD and FT-IR and UV–visible spectroscopy were used for structural characterization of nanofibers. The results showed that not only the microstructure of the polyaniline product, but also other characteristics, for example conductivity, crystallinity, and, more importantly, the efficiency of the process are strongly affected by the synthetic conditions. 相似文献
953.
Use of citric acid as a chelating agent and fuel, ammonium nitrate as fuel, boric acid as flux material and silica as supports, CaWO4:Ln3+@SiO2 (Ln = Er and Tm) nanoparticles were synthesized via a combustion reaction at 800 °C. Characterization of the samples was performed by X-ray diffractometer (XRD), reflectance UV–Vis spectrophotometer, fluorescence spectrophotometer (PL) and transmission electron microscope (TEM). XRD patterns showed that tetragonal crystalline structure of scheelite and silica supports were formed, and that the formation of a silica support could enhance the luminescence intensity of CaWO4:Ln3+. The reflectance UV–Vis and PL spectra indicated the broad absorption band of WO4 2? groups about 240 nm, the WO4 2? wide excitation band with maximum at 240 nm, a broad emission band of WO4 2? with maximum about 420 nm, and characteristic emissions of Ln3+ ions. According to the TEM analysis, CaWO4:Er3+@SiO2 and CaWO4:Tm3+@SiO2 nanoparticles have almost the same morphology with average particle sizes about 50 nm. 相似文献
954.
Uncatalyzed one-pot pseudo-four-component reaction of ethyl pyruvate, anilines, and aldehydes in n-hexane as solvent, under reflux, affords a variety of 3-amino-1,5-dihydro-2H-pyrrol-2-ones in high yield. n-Hexane is an excellent driving force in preparation of the desired products. These compounds have biological and pharmacological properties and are also used in medicinal chemistry. Use of a non-toxic and inexpensive solvent, simple and efficient synthesis, clean work-up, and high yields of the products are the advantages of this method. We report the first catalyst-free method for synthesis this class of compounds. 相似文献
955.
Y. C. Goswami Vijay Kumar P. Rajaram V. Ganesan Mohammad Azad Malik Paul O’Brien 《Journal of Sol-Gel Science and Technology》2014,69(3):617-624
Fluorine doped SnO2 nanostructures were grown using ultrasonic assisted sol–gel method. The gel was obtained by dissolving stannous chloride in methanol with ammonium fluoride as dopant followed by irradiation with ultrasonic vibrations. Obtained samples were characterized by structural, morphological and optical studies. All the peaks in the X-ray diffractograms are identified and indexed as tetragonal cassiterite structure. Negative slope of Williamson–Hall plots indicates compressive strain. Particle size of SnO2 nanostructures is decreases with increases in concentration of fluorine doping. Atomic force microscopy, scanning electron microscopy and transmission electron microscopy studies confirm the formation of ring like porous structures and then hollow tube like growth with increase in the fluorine concentration. Peaks in Raman spectra also indicate strong confinement in SnO2 particles. Distinct peaks in the PL spectra make the structure suitable for photovoltaic applications. 相似文献
956.
TEAD–YAP Interaction Inhibitors and MDM2 Binders from DNA-Encoded Indole-Focused Ugi Peptidomimetics
Verena B. K. Kunig Dr. Marco Potowski Dr. Mohammad Akbarzadeh Dr. Mateja Klika Škopić Denise dos Santos Smith Lukas Arendt Ina Dormuth Dr. Hélène Adihou Blaž Andlovic Dr. Hacer Karatas Shabnam Shaabani Tryfon Zarganes-Tzitzikas Prof. Dr. Constantinos G. Neochoritis Ran Zhang Prof. Dr. Matthew Groves Dr. Stéphanie M. Guéret Dr. Christian Ottmann Prof. Dr. Jörg Rahnenführer Prof. Dr. Roland Fried Prof. Dr. Alexander Dömling Dr. Andreas Brunschweiger 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(46):20518-20522
DNA-encoded combinatorial synthesis provides efficient and dense coverage of chemical space around privileged molecular structures. The indole side chain of tryptophan plays a prominent role in key, or “hot spot”, regions of protein–protein interactions. A DNA-encoded combinatorial peptoid library was designed based on the Ugi four-component reaction by employing tryptophan-mimetic indole side chains to probe the surface of target proteins. Several peptoids were synthesized on a chemically stable hexathymidine adapter oligonucleotide “hexT”, encoded by DNA sequences, and substituted by azide-alkyne cycloaddition to yield a library of 8112 molecules. Selection experiments for the tumor-relevant proteins MDM2 and TEAD4 yielded MDM2 binders and a novel class of TEAD-YAP interaction inhibitors that perturbed the expression of a gene under the control of these Hippo pathway effectors. 相似文献
957.
Yaya Hao Prof. Jiang Li Prof. Qian Li Luhao Zhang Prof. Jiye Shi Prof. Xueli Zhang Prof. Ali Aldalbahi Prof. Lihua Wang Prof. Chunhai Fan Dr. Fei Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(46):20793-20799
The widespread application of CRISPR-Cas9 has transformed genome engineering. Nevertheless, the precision to control the targeting activity of Cas9 requires further improvement. We report a toehold-switch-based approach to engineer the conformation of single guide RNA (sgRNA) for programmable activation of Cas9. This activation circuit is responsive to multiple inputs and can regulate the conformation of the sgRNA through toehold-switch-mediated strand displacement. We demonstrate the orthogonal suppression and activation of Cas9 with orthogonal DNA inputs. Combination of toehold switches leads to a variety of intracellular Cas9 activation programs with simultaneous and orthogonal responses, through which multiple genome loci are displayed in different colors in a controllable manner. This approach provides a new route for programing CRISPR in living cells for genome imaging and engineering. 相似文献
958.
Amirhossein Saali Mohammad Shokouhi Hossein Sakhaeinia Nima Kazemi 《Journal of solution chemistry》2020,49(3):383-404
The thermodynamic consistency test of solubility P–T–x data for binary mixtures including carbon dioxide (CO2) + a room temperature ionic liquid has been investigated. Experimental solubility data taken from the open literature for 32 binary mixtures of CO2/RTILs contains 80 isotherms. The applied consistency test is based on the fundamental Gibbs–Duhem equation with use of the generic Redlich–Kwong (GRK) equation of state (EoS) coupled with the van der Waals–Berthelot (GRK/vdWB) mixing rule. The optimum parameters were obtained by minimizing the summation of per cent relative deviations between modeled and experimental data, based on the bubble pressure algorithm. Modeling was found acceptable for all isotherms, which demonstrated the usability of the GRK equation of state. Results of the thermodynamic consistency test showed that 36 of the isothermal data sets were thermodynamically consistent, 37 were not fully consistent, 6 were thermodynamically inconsistent and only one data set was found to need another model. 相似文献
959.
Nosrati Sahar Molavipordanjani Sajjad Emami Saeed Abedi Seyed Mohammad Talebpour Amiri Fereshteh Hosseinimehr Seyed Jalal 《Journal of Radioanalytical and Nuclear Chemistry》2020,323(1):205-211
This study presents [99mTc]BPTG-1 and [99mTc]BPTG-2 for glioblastoma imaging. In vitro cellular uptakes of these radiotracers were examined in SKOV-3, MCF-7, U87-MG, HT-29, and A549 cell lines. U87-MG cell line displayed the highest radiotracers uptakes. Biodistribution study in U87-MG tumor bearing mice revealed higher uptake of radiotracers in tumor than muscle and brain. Liver, intestine, and kidneys displayed the highest radioactivity uptakes. The main route of radiotracers elimination was hepatobiliary. Due to the brain uptake of these radiotracers, they are promising radiotracers for future studies in the diagnosis of glioblastoma.
相似文献960.
Soodabeh Davaran Mohammad Sadeghinia Zahra Jamalpoor Vahideh Raeisdasteh Hokmabad Mehdi Doosti-Telgerd Ansar Karimian Zahra Sadeghinia Javad Khalilifard Akram keramt Farzad Moradikhah Ali Sadeghinia 《Electrophoresis》2020,41(12):1081-1094
Microfluidic system, or lab-on-a-chip, has grown explosively. This system has been used in research for the first time and then entered in the clinical section. Due to economic reasons, this technique has been used for screening of laboratory and clinical indices. The microfluidic system solves some difficulties accompanied by clinical and biological applications. In this review, the interpretation and analysis of some recent developments in microfluidic systems in biomedical applications with more emphasis on tissue engineering and cancer will be discussed. Moreover, we try to discuss the features and functions of microfluidic systems. 相似文献