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排序方式: 共有182条查询结果,搜索用时 46 毫秒
91.
Bayraktar A Saraçoğlu B Gölgelioğlu Ç Tuncel A 《Journal of colloid and interface science》2012,365(1):63-71
In this study, click chemistry was proposed as a tool for tuning the surface hydrophilicity of monodisperse-macroporous particles in micron-size range. The monodisperse-porous particles carrying hydrophobic or hydrophilic molecular brushes on their surfaces were obtained by the proposed modification. Hydrophilic poly(glycidyl methacrylate-co-ethylene dimethacrylate), poly(GMA-co-EDM) particles were hydrophobized by the covalent attachment of poly(octadecyl acrylate-co-propargyl acrylate), poly(ODA-co-PA) copolymer onto the particle surface via triazole formation by click chemistry. In the second part, Hydrophobic poly(4-chloromethylstyrene-co-divinylbenzene), poly(CMS-co-DVB) particles were hydrophilized by the covalent attachment of poly(vinyl alcohol), PVA onto their surface also via triazole formation by click chemistry. The presence of PVA and poly(ODA-co-PA) copolymer on the corresponding particles was shown by FTIR-DRS. After click-coupling reactions applied for both hydrophobic poly(CMS-co-DVB) and hydrophilic poly(GMA-co-EDM) particles, the marked changes in surface polarity were shown by contact angle measurements. Protein adsorption characteristics of plain and modified particles were investigated for both materials. In the isoelectric point of albumin, the non-specific albumin adsorption decreased from 225 to 80 mg/g by grafting PVA onto the poly(CMS-co-DVB) beads. On the other hand, the non-specific albumin adsorption onto the plain poly(GMA-co-EDM) beads increased from 50 to 400 mg/g by the covalent attachment of poly(ODA-co-PA) copolymer onto the bead-surface via click chemistry. The protein adsorption behavior was efficiently regulated by the covalent attachment of appropriate molecular brushes onto the surfaces of selected particles. The results indicated that "click chemistry" was an efficient tool for controlling the polarity of monodisperse-macroporous particles. 相似文献
92.
Zeynel Kılıç Aytuğ Okumuş Şemsay Demiriz Selen Bilge Aslı Öztürk Nagihan Çaylak Tuncer Hökelek 《Journal of inclusion phenomena and macrocyclic chemistry》2009,65(3-4):269-286
The condensation reactions of N2O3-donor type coronands (1–3) with hexachlorocyclotriphosphazatriene, N3P3Cl6, resulted in the formation of spiro-crypta phosphazene derivatives (4–6). These compounds with excess morpholine and 1,4-dioxa-8-azaspiro[4,5]decane (DASD) afford fully substituted morpholino (7 and 10) and 1,4-dioxa-8-azaspiro[4,5]deca (8)-substituted phosphazene derivatives, respectively. Whilst, in the same conditions, the reactions of 4, 5 and 6 with pyrrolidine, morpholine and DASD also produce partially pyrrolidino-substituted geminal (9 and 11), mono-substituted pyrrolidino (12), morpholino (13) and 1,4-dioxa-8-azaspiro[4,5]deca (14) phosphazenes. It has been clearly observed that the chloride replacement reactions of 4, 5 and 6 with pyrrolidine lead to the geminal products. Compounds 7, 8 and 10 are the first examples of anisochronic tetrakis (amino) phosphazenes according to 31P NMR data. The structures of 7, 8 and 10–14 have been determined by FTIR, MS, 1H, 13C and 31P NMR, DEPT, and HETCOR spectral data. The solid-state structures of 9, 13 and 14 have been examined by X-ray diffraction techniques. The sums of the bond angles around the spiro cyclic nitrogen atoms [344.8(4)° and 347.6(4)°] of 9, indicate that the nitrogen atoms have pyramidal geometries. Thus, the N atoms seem to have stereogenic configurations. Compounds 12–14 also have two stereogenic P-atoms, and they are expected to be in the mixture of enantiomers. The relationships between NPN (α and α′) bond angles and δPspiro values and the correlation of Δ(P–N) with δPspiro and Δ(δP) values are presented. 相似文献
93.
Yener G Üner M Gönüllü Ü Yildirim S Kiliç P Aslan SS Barla A 《Chemical & pharmaceutical bulletin》2010,58(11):1466-1473
Transdermal patches of meloxicam (MX) and lornoxicam (LX) were aimed to be prepared in order to overcome their side effects by oral application. The strategy was formulation of optimized films to prepare transdermal patches by determination of physical properties and investigation of drug-excipient compatibility. As the next step, in vitro drug release, assesment of anti-inflammatory effect on Wistar Albino rats, ex vivo skin penetration and investigation of factors on drug release from transdermal patches were studied. Hydroxypropyl methylcellulose (HPMC) was concluded to be suitable polymer for formulation of MX and LX transdermal films indicating pharmaceutical quality required. MX and LX transdermal patches gave satisfactory results regarding to the edema inhibition in the assessment of anti-inflammatory effect. MX was found out to be more effective compared to LX on relieving of edema and swelling. These results were supported by data obtained from ex vivo penetration experiments of drug through rat skin. Indicative parameters like log P, molecular weight and solubility constraint on penetration rate of drugs also indicated good skin penetration. Transdermal patches of MX and LX can be suggested to be used especially for the immediate treatment of inflammated area since it displays anti-inflammatory effect, soon. 相似文献
94.
Linear-dendritic copolymers containing hyperbranched poly(citric acid) and linear poly(ethylene glycol) blocks (PCA-PEG-PCA) were used as reducing and capping agents to synthesize and support gold nanoparticles (AuNPs). PCA-PEG-PCA copolymers with 1758, 1889 and 3446 molecular weights, called A1, A2 and A3 through this work, respectively, were synthesized using 2, 5, and 10 citric acid/PEG molar ratios. The diameter of A1, A2 and A3 in a fresh water solution was investigated using dynamic light scattering (DLS) and it was between 1.8 and 2.8 nm. AuNPs were simply synthesized and supported by addition a boiling aqueous solution of HAuCl4 to aqueous solutions of A1, A2 and A3. Supported AuNPs were stable in water for several months and agglomeration was not occurred. The loading capacity of A1, A2 and A3 and the size of synthesized AuNPs were investigated using UV spectroscopy and transmission electron microscopy (TEM). It was found that the loading capacity of PCA-PEG-PCA copolymers depend on the concentration of copolymers and the size of their poly(citric acid) parts directly. For example average loading capacities for 400 μM concentration of A1, A2 and A3 were 32.24, 37.4 and 41.52 μM, respectively, and average loading capacities for 400, 200 and 100 μM concentration of A1 were 32.24, 20.28 and 9.1 μM, respectively. Interestingly there was a reverse relation between the size of synthesized AuNPs and size of poly(citric acid) parts of PCA-PEG-PCA copolymers. 相似文献
95.
96.
Dr. Pere Miró Mahdi Ghorbani‐Asl Prof. Dr. Thomas Heine 《Angewandte Chemie (International ed. in English)》2014,53(11):3015-3018
The structure and electronic structure of layered noble‐transition‐metal dichalcogenides MX2 (M=Pt and Pd, and chalcogenides X=S, Se, and Te) have been investigated by periodic density functional theory (DFT) calculations. The MS2 monolayers are indirect band‐gap semiconductors whereas the MSe2 and MTe2 analogues show significantly smaller band gap and can even become semimetallic or metallic materials. Under mechanical strain these MX2 materials become quasi‐direct band‐gap semiconductors. The mechanical‐deformation and electron‐transport properties of these materials indicate their potential application in flexible nanoelectronics. 相似文献
97.
Jabbar Khalafy Mahnaz Ezzati Mehdi Rimaz Ahmad Poursattar Marjani Hooman Yaghoobnejad Asl 《Journal of the Iranian Chemical Society》2014,11(4):1067-1074
A study concerning the new substituted cinnoline synthesis is described. The use of a one-pot three-component method allows a simple regioselective and efficient synthesis of cinnoline derivatives via reaction of arylglyoxals with 1,3-cyclohexanedione and dimedone in the presence of hydrazine hydrate. 相似文献
98.
Let(M,ω)be a symplectic manifold.In this paper,the authors consider the notions of musical(bemolle and diesis)isomorphisms ω~b:T M→T~*M and ω~?:T~*M→TM between tangent and cotangent bundles.The authors prove that the complete lifts of symplectic vector field to tangent and cotangent bundles is ω~b-related.As consequence of analyze of connections between the complete lift ~cω_(T M )of symplectic 2-form ω to tangent bundle and the natural symplectic 2-form dp on cotangent bundle,the authors proved that dp is a pullback o f~cω_(TM)by ω~?.Also,the authors investigate the complete lift ~cφ_T~*_M )of almost complex structure φ to cotangent bundle and prove that it is a transform by ω~?of complete lift~cφ_(T M )to tangent bundle if the triple(M,ω,φ)is an almost holomorphic A-manifold.The transform of complete lifts of vector-valued 2-form is also studied. 相似文献
99.
Ezat Hamidi‐Asl Jahan Bakhsh Raoof Reza Ojani Mohammad Saeid Hejazi 《Electroanalysis》2013,25(9):2075-2083
A new electrochemical PNA hybridization biosensor for detection of a 15‐mer sequence unique to p53 using indigo carmine (IC) as an electrochemical detector is described in this work. This genosensor is based on the hybridization of target oligonucleotide with its complementary probe immobilized on the gold electrode by self‐assembled monolayer formation. Because this label is electroactive in acidic medium, the interaction between IC and short sequence of p53 is studied by differential pulse voltammety (DPV) in 0.1 M H2SO4. The results of electrochemical impedance spectroscopy and cyclic voltammetry in the solution of [Fe(CN)6]3?/4? shows no breakage in PNA‐DNA duplex. A decrease in the voltammetric peak currents of IC is observed upon hybridization of the probe with the target DNA. The influence of probe concentration on effective discrimination against non‐complementary oligonucleotides is investigated and a concentration of 10?7 M is selected. The diagnostic performance of the PNA sensor is described and the detection limit is found to be 4.31×10?12 M. 相似文献
100.
Manouchehr Mamaghani Abed Badrian 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):1181-1186
The hydroxy group of the Baylis-Hillman adducts was protected with trimethylsilyl (TMS) group using the reaction of adducts 1a–h with hexamethyldisilazane (HMDS) catalyzed by iodine under nearly neutral reaction conditions. 相似文献