|
| ||
|
|
||
CD Molecules (cd + molecule)
Selected AbstractsComplexation of aminoglutethimide with native and modified cyclodextrinsJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 10 2009Michal Nowakowski Abstract Complexations of R(+) and RS(+/,)aminoglutethimide (AGT), the drug used in a treatment of breast and prostate cancer with native and modified cyclodextrins (, -CD, , -CD, , -CD, 2,6-di- O -methyl- , -CD (DM- , -CD), 2,3,6-tri- O -methyl- , -CD (TM- , -CD) and carboxymethyl- , -CD (CM- , -CD)) were studied. The stability constants were determined with UV,Vis spectrophotometric method at pH 9.0. The NMR data obtained for TM- , -CD suggest that the complexation of AGT is possible from both sides of CD molecule. This was confirmed by molecular dynamic simulations. Copyright © 2009 John Wiley & Sons, Ltd. [source] A Thermoresponsive Membrane for Chiral Resolution,ADVANCED FUNCTIONAL MATERIALS, Issue 4 2008Mei Yang Abstract A novel thermoresponsive membrane for chiral resolution with high performance has been developed. The membrane exhibits chiral selectivity based on molecular recognition of beta-cyclodextrin (, -CD) and thermosensitivity based on the phase transition of poly(N -isopropylacrylamide) (PNIPAM). Linear PNIPAM chains were grafted onto porous nylon-6 membrane substrates by using a plasma-graft pore-filling polymerization method; the chains thus acted as microenvironmental adjustors for , -CD molecules. , -CD moieties were introduced into the linear PNIPAM chains by a chemical grafting polymerization method and acted as chiral selectors. The phase transition of grafted PNIPAM chains affects the microenvironment of , -CD molecules and, thus, the association between , -CD and guest molecules. The chiral selectivity of the prepared thermoresponsive membranes in chiral resolution operated at temperature below the lower critical solution temperature (LCST) of PNIPAM is higher than that of membranes with no thermosensitivity. Furthermore, the decomplexation ratio of enantiomer-loaded thermoresponsive membranes in decomplexation at temperatures above the LCST is much higher than that of membranes with no thermosensitivity. Thus, by simply changing the operation temperature, high, selective chiral resolution and efficient membrane regeneration are achieved. The proposed membrane provides a new and efficient way to solve the difficult decomplexation problem of chiral solid membranes, which is highly attractive for chiral resolution. [source] Flow cytometric technique for determination of prostasomal quantity, size and expression of CD10, CD13, CD26 and CD59 in human seminal plasmaINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 2 2006LENA CARLSSON Summary Prostasomes are prostate-derived organelles in seminal plasma exhibiting pluripotent properties to facilitate the fertilization process. Seminal prostasome concentration, size distribution and expression of the prostasomal surface antigens CD10, CD13, CD26 and CD59 were examined by flow cytometry. The study group consisted of 79 men with involuntary infertility. Very strong correlations existed between the prostasome expressions of the different CD markers. Significant correlations between prostasome concentration and CD molecules were weak or lacking. Further, no or weak relationships were observed between the prostasomal CD markers and sperm morphology, seminal fructose, neutral , -glucosidase activity, zinc and tumour necrosis factor , concentrations. Flow cytometry is a practical way to study prostasomes in seminal fluid without prior separation. This is a new technique for evaluation of the role of prostasomes and their functions in male reproductive physiology. [source] Preparation and adsorption of novel cellulosic fibers modified by , -cyclodextrinPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 4 2008Youyi Xia Abstract Novel cellulosic fibers modified by , -cyclodextrin (CFEC) were prepared for adsorption for heavy metal ions like copper (II) and organic dye like neutral red from their aqueous solutions. The modified cellulosic fibers gave higher copper ion adsorption, and showed copper ion uptake values of 6.24,mg/g at 293°C, as against no adsorption for unmodified cellulosic fibers. Adsorption isotherm model indicated the adsorption of the novel modified fibers for heavy metal ions best fitted for Langmiur model. The adsorption was an exothermic reaction, and the reaction caloric was 6.295,kJ/mol. Copper ions could form a 7:4 complex with , -cyclodextrin (, -CD). The novel modified cellulosic fibers could also form inclusion complexes with neutral red via , -CD molecules. In addition, it was found that the novel modified cellulosic fibers had nearly the same mechanical and thermal properties as the unmodified cellulosic fibers because the modification did not destroy the main chain of cellulose molecules. Copyright © 2008 John Wiley & Sons, Ltd. [source] Rheology control by modulating hydrophobic and inclusive associations of side-groups in poly (acrylic acid)ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Jie Wang Abstract In this article we demonstrated that the viscosities of modified poly (acrylic acid) (PAA) solutions were tunable by modulating the hydrophobic and inclusion association between alkyl groups and ,-cyclodextrin (,-CD) groups grafted to PAA. The viscosity can be controlled by changing the host,guest molar ratio, alkyl chain length, polymer concentration, salt concentration, pH value, temperature, or addition of native ,-CD. A viscosity maximum for inclusive polymer networks constructed by mixing hydrophobically modified PAA (HMPAA) and ,-CD,modified PAA (,-CDPAA) appeared at the alkyl : ,-CD molar ratio of 1:1, which implies the inclusion association between HM and ,-CD grafts is binary. Longer side chain length or higher polymer concentration led to higher viscosity for aqueous HMPAA solution with only hydrophobic association or its mixture with ,-CDPAA with inclusion association. Monotonically increasing the ionic strength or pH value resulted in a viscosity maximum due to the competition between electrostatic repulsion and hydrophobic or inclusive association. The hydrophobic interactions of alkyl groups could be masked by native ,-CD, and the networks of HMPAA and ,-CDPAA mixture deconstructed upon addition of native ,-CD molecules. The storage modulus and loss modulus of hydrophobic HMPAA and inclusive HMPAA + ,-CDPAA solutions obey time,temperature superposition. The horizontal and vertical temperature shift factors obeyed a simple-exponential Arrhenius relationship, where the activation energies for hydrophobic association system were found to be 3.4 and , 12.1 kJ/mol, and for inclusive association system 53.9 and , 2.9 kJ/mol, respectively. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Face-Selective [2]- and [3]Rotaxanes: Kinetic Control of the Threading Direction of CyclodextrinsCHEMISTRY - A EUROPEAN JOURNAL, Issue 25 2007Tomoya Oshikiri Abstract New [2]- and [3]pseudorotaxanes containing ,-cyclodextrin (,-CDs) molecules as rotors and alkyl pyridinium derivatives as axles were prepared by a slipping process. The inclusion behavior of these rotaxanes was investigated by using one- and two-dimensional NMR spectroscopy. The methyl group at the 2-position of the pyridinium moiety at the end of each axle molecule was found to control the rates of threading of the ,-CD onto the axle molecules. ,-CD can approach axle molecules from a particular direction to form inclusion complexes. Axle molecules that contain a 2-methylpyridinium moiety at one end and a bulky stopper at the other end can regulate the direction of approach to give a [2]pseudorotaxane such as 2,b,,-CD. A [3]pseudorotaxane in which two ,-CD molecules are arranged facing in the same direction at two stations of the tetracationic axle molecule was also obtained. These face-selective behaviors are dominated by kinetic processes rather than thermodynamic processes. [source] | |||||||||||||