http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Liu, Di,Bielawski, Christopher W John Wiley Sons, Ltd 2017 Polymer international Vol.66 No.1
<P><B>Abstract</B></P><P>Azido‐functionalized isotactic polypropylene was prepared via the direct CH azidation of a commercially available polymer using a stable azidoiodinane. Including imidazole or benzimidazole in the reaction mixture was found to significantly improve the yields of the post‐polymerization modification. Although chain cleavage was observed, the methodology afforded high‐molecular‐weight (<I>M</I><SUB>w</SUB> > 100 kDa) functionalized polypropylene containing up to 3 mol% of azido groups and enabled access to polypropylene‐<I>graft</I>‐poly(ethylene glycol) copolymers via azide–alkyne cycloaddition chemistry. © 2016 Society of Chemical Industry</P>
Winnicka, Katarzyna,Bielawski, Krzysztof,Bielawska, Anna,Miltyk, Wojciech 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.10
We examined the effects of three cardiac glycosides, ouabain, digoxin and proscillaridin A, on the proliferation of estrogen independent MDA-MB-231 breast cancer cells. In terms of reduction in cell viability, the compounds rank for both 24 hand 48 h of incubation in MDA-MB-231 cells in the order proscillaridin A > digoxin > ouabain. Digoxin for 24 hand 48 h of incubation in MDA-MB-231 cells proved to be only slightly more potent than ouabain, with $IC_{50}$ values of $122{\pm}2\;and\;70{\pm}2nM$, respectively, compared to $150{\pm}2\;and\;90{\pm}2nM$ for ouabain. In contrast, proscillaridin A, was much more active and showed a high level of cytotoxic potency, $IC_{50}\;51{\pm}2\;and\;15{\pm}2nM$ for 24 hand 48 h of incubation, respectively. The concentrations of digoxin, ouabain and proscillaridin A needed to inhibit [$^3H$]thymidine incorporation into DNA by 50% ($IC_{50}$) in MDA-MB-231 cells for 24 h of incubation were found to be $124{\pm}2nM,\;142{\pm}2nM,\;and\;48{\pm}2nM$, respectively. In the present study, we demonstrated that ouabain, digoxin, and proscillaridin A induce apoptosis in MDA-MB-231 cells by increasing free calcium concentration and by activating caspase-3.
Ionic Liquid Crystals: Versatile Materials
Goossens, Karel,Lava, Kathleen,Bielawski, Christopher W.,Binnemans, Koen American Chemical Society 2016 Chemical reviews Vol.116 No.8
<P>This Review covers the recent developments (2005-2015) in the design, synthesis, characterization, and application of thermotropic ionic liquid crystals. It was designed to give a comprehensive overview of the 'state-of-the-art' in the field. The discussion is focused on low molar mass and dendrimeric thermotropic ionic mesogens, as well as selected metal-containing compounds (metallomesogens), but some references to polymeric and/or lyotropic ionic liquid crystals and particularly to ionic liquids will also be provided. Although zwitterionic and mesoionic mesogens are also treated to some extent, emphasis will be directed toward liquid-crystalline materials consisting of organic cations and organic/inorganic anions that are not covalently bound but interact via electrostatic and other noncovalent interactions.</P>
Burgess Reagent Facilitated Alcohol Oxidations in DMSO
Sultane, Prakash R.,Bielawski, Christopher W. American Chemical Society 2017 Journal of organic chemistry Vol.82 No.2
<P>The Burgess reagent ([methoxycarbonylsulfamoyl]triethylammonium hydroxide) has historically found utility as a dehydrating agent. Herein we show that, in the presence of dimethyl sulfoxide, the Burgess reagent efficiently and rapidly facilitates the oxidation of a broad range of primary and secondary alcohols to their corresponding aldehydes and ketones in excellent yields and under mild conditions, and can be combined with other transformations (e.g., Wittig olefinations). A mechanism similar to those described for the Pfitzner-Moffatt and Swern oxidations is proposed.</P>
Katarzyna Winnicka,Krzysztof Bielawski,Anna Bielawska,Wojciech Miltyk 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.10
We examined the effects of three cardiac glycosides, ouabain, digoxin and proscillaridin A, on the proliferation of estrogen independent MDA-MB-231 breast cancer cells. In terms of reduction in cell viability, the compounds rank for both 24 h and 48 h of incubation in MDA-MB-231 cells in the order proscillaridin A > digoxin > ouabain. Digoxin for 24 h and 48 h of incubation in MDA-MB-231 cells proved to be only slightly more potent than ouabain, with IC50 values of 122 ± 2 and 70 ± 2 nM, respectively, compared to 150 ± 2 and 90 ± 2 nM for ouabain. In contrast, proscillaridin A, was much more active and showed a high level of cytotoxic potency, IC50 51 ± 2 and 15 ± 2 nM for 24 h and 48 h of incubation, respectively. The concentrations of digoxin, ouabain and proscillaridin A needed to inhibit [3H]thymidine incorporation into DNA by 50% (IC50) in MDA-MB-231 cells for 24 h of incubation were found to be 124 ± 2 nM, 142 ± 2 nM, and 48 ± 2 nM, respectively. In the present study, we demonstrated that ouabain, digoxin, and proscillaridin A induce apoptosis in MDA-MB-231 cells by increasing free calcium concentration and by activating caspase-3.
Metal-promoted C1 polymerizations
Cahoon, Collin R.,Bielawski, Christopher W. Elsevier 2018 Coordination chemistry reviews Vol.374 No.-
<P><B>Abstract</B></P> <P>C1 polymerizations provide a means to grow polymer chains one carbon atom at a time. Such methodology enables the synthesis of persubstituted polymers that are challenging to prepare using conventional C2 polymerizations, which typically utilize alkene-based monomers and thus grow polymer chains two carbons at a time. Persubstituted polymers feature higher densities of pendant functional groups and, as such, offer the potential to exhibit enhanced physical and/or chemical properties over their monosubstituted C2 polymer analogues. This review summarizes the various metals that have been used to promote C1 polymerizations in a catalytic or stoichiometric manner. Discussions are stratified according to the monomers used, which are formally carbenes or carbynes and typically employed as their respective ylides, isocyanides, diazo compounds, or geminal di- or trihalides. Emphasis is placed on the scope of the polymerization chemistry, underlying mechanisms, and outstanding opportunities in the field.</P> <P><B>Highlights</B></P> <P> <UL> <LI> C1 polymerizations offer access to highly substituted polymers. </LI> <LI> C1 polymers often exhibit unique properties due to the high densities of functional groups. </LI> <LI> Polymerizations of diazo compounds have been catalyzed by Cu, Au, Pd, and Rh. </LI> <LI> Polymerizations of isocyanides have been catalyzed by Ni, Co, Pd, and Rh. </LI> <LI> Polymerizations of geminal di- and trihalides have been promoted with Mg, Li, Zn, and Na/K. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
( Stanfield Youngwon Lee ),( Christopher Bielawski ),정동영,강윤식,이명재,신희종,김미주,성영은 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1
Our work focused on determining if this outer Helmholtz plane reaction does indeedexist and play a significant role in non-precious metal catalysts. A three electrode half-cell was used tomeasure the oxygen reduction reaction activity of a non-precious metal catalystin different alkaline electrolytes. Using electrolytes with different cations altered the hydration energyas well as block or increase access of oxygen to the outer Helmholtzplane. Correlations between hydrationshell size and catalytic activity were observed.