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951.
Jong Eel Park Kyeong Wan Woo Sang Un Choi Je Hyun Lee Kang Ro Lee 《Helvetica chimica acta》2014,97(1):56-63
Two new spirostane‐steroidal saponins, bletilnoside A ( 1 ) and bletilnoside B ( 2 ), together with five known compounds, 3 – 7 , were isolated from the roots of Bletilla striata (Thunb .) Reichb . F. The structures of the new compounds were determined based on their 1D‐ and 2D‐NMR spectral data. The isolated compounds 1 – 7 were tested for cytotoxicity against four human tumor cells (A549, SK‐OV‐3, SK‐MEL‐2, and HCT15) in vitro using a sulforhodamin B bioassay, and compounds 1, 2 , and 5 showed significant cytotoxicities against all tested tumor cell lines with IC50 values ranging from 3.98±0.16 to 12.10±0.40 μM . 相似文献
952.
Mirosław Zarębski Magdalena Kordon Jurek W. Dobrucki 《Photochemistry and photobiology》2014,90(3):709-715
We describe a study of the influence of a dose rate, i.e. light intensity or photon flux, on the efficiency of induction of a loss of integrity of plasma membranes of live cells in culture. The influence of a photon flux on the size of the light dose, which was capable of causing lethal effects, was measured in an experimental system where singlet oxygen was generated exclusively outside of live cells by ruthenium(II) phenantroline complex. Instantaneous, sensitive detection of a loss of integrity of a plasma membrane was achieved by fluorescence confocal imaging of the entry of this complex into a cell interior. We demonstrate that the size of the lethal dose of light is directly proportional to the intensity of the exciting light. Thus, the probability of a photon of the exciting light inflicting photosensitized damage on plasma membranes diminishes with increasing density of the incident photons. 相似文献
953.
PMB ethers of alcohols are obtained in good yields and under mild conditions using the 4-methoxybenzyl N-allyl thiocarbamate and N-bromosuccinimide (NBS)/TfOH as the catalyst. The present method is very fast, simple, and efficient. 相似文献
954.
Brownian dynamics simulations on CPU and GPU with BD_BOX 总被引:1,自引:0,他引:1
There has been growing interest in simulating biological processes under in vivo conditions due to recent advances in experimental techniques dedicated to study single particle behavior in crowded environments. We have developed a software package, BD_BOX, for multiscale Brownian dynamics simulations. BD_BOX can simulate either single molecules or multicomponent systems of diverse, interacting molecular species using flexible, coarse-grained bead models. BD_BOX is written in C and employs modern computer architectures and technologies; these include MPI for distributed-memory architectures, OpenMP for shared-memory platforms, NVIDIA CUDA framework for GPGPU, and SSE vectorization for CPU. 相似文献
955.
Iwona Łakomska Anna Kaźnica Romana Joachimiak Andrzej Marszałek Jerzy Sitkowski Lech Kozerski Tomasz Drewa 《Chemical Papers》2011,65(3):308-314
A novel platinum(IV) coordination compound with 6-mercaptopurine (6-Hmp) has been synthesised and characterised by IR and
NMR spectroscopy. Spectroscopic parameters indicate the presence of two chelate (S-6, N-7) monodeprotonated ligands and two
chloride ions in the coordination sphere of [PtCl2(6-mp)2] · H2O (I). Two Pt(IV) coordination compounds, [PtCl2(6-mp)2] · H2O (I) and [PtCl4(dbtp)2] (II), were used in the in vivo test against B16 mouse melanoma tumours. Cytotoxic activity of compound II against the tumour cells was found to be high (LC10 = 2.6 μM, LC50 = 17.0 μM, LC90 = 58.0 μM) compared to that of cisplatin. 相似文献
956.
Anita Leitgeb Anna Szadkowska Michal Michalak Michał Barbasiewicz Karol Grela Christian Slugovc 《Journal of polymer science. Part A, Polymer chemistry》2011,49(15):3448-3454
A family of four different Hoveyda‐type initiators bearing a π‐extended carbene ligand was characterized regarding the activity in ring opening metathesis polymerization. One of the initiators shows high activity at ambient temperature, similar to the second generation Hoveyda–Grubbs catalyst and is even suited for the controlled polymerization of certain norbornene derivatives. The other family members exhibit a pronounced latency at room temperature, and polymerization can be triggered by heat. The scope of these initiators in the thermally triggered polymerizations of norbornene derivatives in general and dicyclopentadiene in particular was disclosed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011. 相似文献
957.
Adamczyk Z Barbasz J Cieśla M 《Langmuir : the ACS journal of surfaces and colloids》2011,27(11):6868-6878
Adsorption of fibrinogen, modeled as a linear chain of touching beads of various sizes, was theoretically studied using the random sequential adsorption (RSA) model. The adsorption process was assumed to consist of two steps: (i) formation of an irreversibly bound fibrinogen monolayer under the side-on orientation, which is independent of the bulk protein concentration and (ii) formation of the reversibly bound, end-on monolayer, whose coverage was dependent on the bulk concentration. Calculation based on the RSA model showed that the maximum surface concentration of the end-on (reversible) monolayer equals N(⊥∞) = 6.13 × 10(3) μm(-2) which is much larger than the previously found value for the side-on (irreversible) monolayer, equal to N(∞) = 2.27 × 10(3) μm(-2). Hence, the maximum surface concentration of fibrinogen in both orientations is determined to be 8.40 × 10(3) μm(-2) corresponding to the protein coverage of 5.70 mg m(-2) assuming 20% hydration. Additionally, the surface blocking function (ASF) was determined for the end-on fibrinogen adsorption, approximated for the entire range of coverage by the interpolating polynomial. For the coverage approaching the jamming limit, the surface blocking function (ASF) was shown to vanish proportionally to (θ(⊥∞) - θ(⊥))(2). These calculation allowed one to theoretically predict adsorption isotherms for the end-on regime of fibrinogen and adsorption kinetics under various transport conditions (diffusion and convection). Using these theoretical results, a quantitative interpretation of experimental data obtained by TIRF and ellipsometry was successfully performed. The equilibrium adsorption constant for the end-on adsorption regime was found to be 8.04 × 10(-3) m. On the basis of this value, the depth of the adsorption energy minimum, equal to -17.4 kT, was predicted, which corresponds to ΔG = -41.8 kJ mol(-1). This is in accordance with adsorption energy derived as the sum of the van der Waals and electrostatic interactions. Besides having significance for predicting fibrinogen adsorption, theoretical results derived in this work also have implications for basic science providing information on mechanisms of anisotropic protein molecule adsorption on heterogeneous surfaces. 相似文献
958.
Irina V. Terekhova Malgorzata Koźbiał Roman S. Kumeev Gennady A. Alper 《Journal of solution chemistry》2011,40(8):1435-1446
Inclusion complex formation of hydroxypropylated α-, β- and γ-cyclodextrins with riboflavin (vitamin B2) and alloxazine was studied by spectroscopic and solubility methods. Alloxazine, which is a structural analog of riboflavin,
was considered in order to evaluate the role of ribityl and methyl substituents in complexation. Thermodynamic parameters
for 1:1 complex formation were obtained and analyzed in terms of influence of the reagent structure on the binding process.
It was shown that the cavity of hydroxypropyl-β-cyclodextrin is more appropriate for formation of stable complexes. The complexes are enthalpy stabilized, due to prevalence
of van der Waals interactions and possible hydrogen bonding. The partial insertion of riboflavin into the cyclodextrin cavity
was revealed by 1H NMR and computer modeling. The ribityl side chain, which prevents deep inclusion, is located nearby the wider rim of the
cyclodextrin molecule and can undergo destruction. Penetration of the alloxazine molecule into the macrocyclic cavity is deeper
and accompanied by formation of more stable inclusion complexes. Hydroxypropyl-β-cyclodextrin was found to be the more efficient solubilizing agent for riboflavin and alloxazine, whereas a stabilization
action of cyclodextrins towards riboflavin was not observed. 相似文献
959.
960.
Pawe? Niedzia?kowski Tadeusz Ossowski Rados?aw Majewski Zdzis?awa Nowakowska Grzegorz Schroeder 《Monatshefte für Chemie / Chemical Monthly》2011,89(3):1121-1129