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21.
A new calixcrown‐6 oligomer 5 was synthesized by reacting a 1,3‐distal di‐amino derivative of cone p‐tert‐butylcalix[4]crown‐6 with malonyl dichloride. Extraction studies with precursor monomers 2 and 3 and oligomer 5 showed differences in their metal cation extraction behavior and selectivity. Precursors monomers 2 and 3 were selective for Hg2+; whereas, oligomer 5 showed high affinity towards both alkali (Li+, Na+, K+, and Cs+) and heavy metal cations (Cu2+, Cd2+, Hg2+ and Pb2+). 相似文献
22.
Sevtap Yildiz Faruk Yilmaz Haluk Özbek Önder Pekcan Koi˙chi˙ Ito 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1573-1588
Random copolymers of poly(ethylene oxide) macromonomer with p‐vinylbenzyl end‐functional group (PEOVB) and liquid crystalline monomer, namely 6‐(4‐cyanobiphenyl‐4′‐oxy)hexyl acrylate (COA), were prepared by conventional free radical polymerization. A living anionic polymerization technique was employed for the synthesis of PEO macromonomers bearing p‐vinylbenzyl moiety at one end. The photon transmission method was also applied to study the phase transitions of COA monomer and its random copolymer with PEO. It was found that, for both samples, the nematic‐smectic A transition is continuous, but the critical fluctuation regions do not allow to obtain 3D XY values. Instead, we have obtained the values close to mean field regime. Scaling of thermal hystersis for random copolymer sample near the nematic‐isotropic transition was studied as well. Thermal hysteresis loops were produced under linearly varying temperature. It was shown that the areas of the hysteresis loops scale with the temperature scanning rate with an exponent being equal to 0.614 which is in good agreement with the field‐theoretical value. 相似文献
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Three magnetically recoverable Brønsted acidic calix[n]arene derivatives were successfully constructed by immobilizing calix[n]arene sulfonic acids onto silica-coated magnetic nanoparticles, a process, which allows calix[n]arene derivatives to acquire magnetic properties. All of the magnetically recoverable Brønsted acidic calix[n]arenes efficiently catalyze the coupling of electron-rich arenes with some alcohols in water. After separation and recovery from the reaction mixture by a simple magnet, these Brønsted acidic calix[n]arenes can be recycled many times without losing their catalytic activity. 相似文献
25.
Fiber-optic beam shaper based on multimode interference 总被引:1,自引:0,他引:1
A new method of fiber-optic based beam shaping is investigated both numerically and experimentally. A cylindrically symmetric method of lines (MoLs) is developed to simulate the device. The device is fabricated by fusion splicing a predetermined length of multimode fiber (MMF) to a single-mode fiber. The multimode interference (MMI) effects create ring-shaped field profiles at certain positions inside the MMF. The shaped beam can be used in medical applications requiring particular irradiation patterns. 相似文献
26.
N. B. Mutlu Ağardan Z. Değim Ş. Yilmaz 《Journal of inclusion phenomena and macrocyclic chemistry》2014,80(1-2):31-36
A new nanoparticle formulation has been developed by using dimethyl-β-cyclodextrin (DM-β-CD) with raloxifene HCl or tamoxifene citrate. Both drugs are insoluble in water and represent as low bioavailibilities when given orally. Tamoxifen has an FDA approval for breast cancer prevention and the treatment. Raloxifene is approved for osteoprosis treatment. Both drugs were selected as a model drug antitumoural activity and MMP-2 inhibition studies were evaluated on breast cancer cell lines MCF-7 and MDA-MB 231. MMP-2 is known to be responsible for tumour invasion and initation the of angiogenesis. DM-β-CD and sodium taurocholate (NaTC) have been used as absorption enhancers to increase penetration effect of raloxifene/tamoxifen on the tumour cells and aimed to provide high antitumoral activity and MMP-2 inhibition results by developed nanoparticle formulations. The effects of two absorption enhancers were compared. The highest antitumoral activity was observed for DM-β-CD—raloxifene HCl nanoparticle formulation and also MMP-2 enzyme inhibit effectively. 相似文献
27.
Benedikt Jedlitzke Zahide Yilmaz Wolfgang Drner Henning D. Mootz 《Angewandte Chemie (International ed. in English)》2020,59(4):1506-1510
Photocaged antibody fragments, termed photobodies, have been developed that are impaired in their antigen‐binding capacity and can be activated by irradiation with UV light (365 nm). This rational design concept builds on the selective photocaging of a single tyrosine in a nanobody (a single‐domain antibody fragment). Tyrosine is a frequently occurring residue in central positions of the paratope region. o‐Nitrobenzyl‐protected tyrosine variants were incorporated into four nanobodies, including examples directed against EGFR and HER2, and photodeprotection restores the native sequence. An anti‐GFP photobody exhibited an at least 10 000‐fold impaired binding affinity before photodeprotection compared with the parent nanobody. A bispecific nanobody–photobody fusion protein was generated to trigger protein heterodimerization by light. Photoactivatable antibodies are expected to become versatile protein reagents and to enable novel approaches in diagnostic and therapeutic applications. 相似文献
28.
Sevim Hamamci Veysel T. Yilmaz Sedat Gumus Orhan Büyükgüngör 《Structural chemistry》2008,19(1):123-129
A silver(I) complex of saccharinate (sac) with pyrazine (pyz), [Ag(sac)(pyz)] n , has been synthesized and characterized by elemental analysis, IR, thermal analysis, and single-crystal X-ray diffractometry. The complex crystallizes orthorhombic space group Pnma with unit cell parameters of a = 13.0073(9) Å, b = 6.4907(6) Å, c = 13.4007(9) Å, V = 1131.37(15) Å3, and Z = 4. [Ag(sac)(pyz)] n is a one-dimensional coordination polymer, in which the sac ligand acts as a monodentate ligand through the N atom and the trigonal silver centers are linked by the bridging pyz ligands. The individual chains are connected into two-dimensional supramolemular network by aromatic π(sac)···π(pyz) stacking interactions. The FTIR spectrum of [Ag(sac)(pyz)] n has been recorded in the region and 4,000–400 cm?1. The optimized geometry, frequency, and intensity of the vibrational bands of [Ag(sac)(pyz)] n were obtained by density functional theory (DFT) at the B3LYP level. The vibrational frequencies were calculated and the scaled values have been compared with the experimental FTIR data. The observed and calculated frequencies are found to be in good agreement. 相似文献
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30.
Tuba Gulsen Irena Jadlovsk Emrah Yilmaz 《Mathematical Methods in the Applied Sciences》2021,44(1):985-992
In this study, we consider parameter‐dependent diffusion eigenvalue problem on time scales. An upper bound on the number of eigenvalues for this problem on a finite time scale is given. 相似文献