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https://www.readbyqxmd.com/read/29777615/tools-for-work-up-and-pre-purification-of-tritium-labelled-small-molecules
#1
Dieter Muri, Martin R Edelmann
This practitioner protocol describes the use and application of different types of solid phase extractions and metal scavengers for small scale reactions, particularly in the context of purifying tritiated molecules from heavily contaminated reaction mixtures. Polymer-bound strong cation exchangers are especially suitable for separating basic compounds from neutral or acidic molecules and have been widely applied in the work-up of Iridium-based hydrogen isotope exchange reactions. Polymer-bound strong anion exchangers can help to separate acidic compounds from their neutral or basic counterparts or to easily convert a TFA or formate salt to its free base after HPLC purification...
May 19, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
https://www.readbyqxmd.com/read/29766713/probing-dna-hybridization-equilibrium-by-cationic-conjugated-polymer-for-highly-selective-detection-and-imaging-of-single-nucleotide-mutation
#2
Zehao Li, Xu Zhou, Lidan Li, Shue Liu, Congshan Wang, Lina Li, Changyuan Yu, Xin Su
Hybridization-based probes emerge as a promising tool for nucleic acid target detection and imaging. However, the single-nucleotide selectivity is still challenging because the specificity of hybridization reaction is typically low at room temperature. We disclose an effective and simple method for highly selective detection and in situ imaging of single-nucleotide mutation (SNM) by taking the advantages of the specific hybridization of short duplex and the signal amplifying effect of cationic conjugated polymer (CCP)...
May 16, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29766175/bismuth-as-a-versatile-cation-for-luminescence-in-coordination-polymers-from-bix-3-4-4-bipy-understanding-of-photophysics-by-quantum-chemical-calculations-and-structural-parallels-to-lanthanides
#3
Jens R Sorg, Tobias Wehner, Philipp R Matthes, Rebecca Sure, Stefan Grimme, Johanna Heine, Klaus Müller-Buschbaum
Coordination polymers (CPs) with bismuth(iii) as a connectivity centre have been prepared from BiX3 (X = Cl-I) and 4,4'-bipyridine (bipy) in order to implement Bi-based luminescence. The products were obtained via different synthetic routes such as solution chemistry, melt syntheses or mechanochemical reactions. Five neutral and anionic 1D-CPs are presented that show a chemical parallel to trivalent lanthanides forming isostructural or closely related 1D-CPs, of which five additional compounds are described...
May 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29762022/counterion-controlled-formation-of-an-octanuclear-uranyl-cage-with-cis-1-2-cyclohexanedicarboxylate-ligands
#4
Pierre Thuéry, Youssef Atoini, Jack Harrowfield
cis-1,2-Cyclohexanedicarboxylic acid ( c-chdcH2 ) was reacted with uranyl nitrate under (solvo-)hydrothermal conditions in the presence of different possible counterions. Two neutral complexes of 1:1 stoichiometry were obtained, [UO2 ( c-chdc)(DMF)] (1) and [UO2 ( c-chdc)(H2 O)] (2), which crystallize as two-dimensional coordination polymers and do not include the additional cations present in solution. In contrast, the complex [NH4 ][PPh4 ][(UO2 )8 ( c-chdc)9 (H2 O)6 ]·3H2 O (3) crystallized in the presence of PPh4 Br, ammonium cations being generated in situ from acetonitrile hydrolysis...
May 15, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29758104/restricted-speciation-and-supramolecular-assembly-in-the-5f-block
#5
Korey P Carter, Robert G Surbella Iii, Mark Kalaj, Christopher L Cahill
Hybrid materials bearing elements from the 5f block display a rich diversity of coordination geometries, connectivities, and assembly motifs. Exemplary in this regard have been the uranyl coordination polymers, which feature a wide range of secondary building units resulting from hydrolysis and oligomerization of the [UO2]2+ cation. An alternative approach to novel materials, however, suppresses hydrolysis and relies on non-covalent interactions (e.g. hydrogen or halogen bonding) to direct assembly of a more limited suite of species or building units...
May 14, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29757480/pinenes-abundant-and-renewable-building-blocks-for-a-variety-of-sustainable-polymers
#6
Malte Winnacker
Pinenes - a group of monoterpenes containing a double bond - are very suitable renewable building blocks for a variety of sustainable polymers and materials. Their abundance from mainly non-edible parts of plants as well as the feasibility to isolate them render these compounds unique amongst the variety of biomass that is utilizable for novel materials. Accordingly, their use for the synthesis of biobased polymers has been investigated intensively, and strong progress has been made with this especially within the past 2-3 years...
May 14, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29756408/-ph3c-b-c6f5-4-highly-efficient-metal-free-single-component-initiator-for-helical-sense-selective-cationic-copolymerization-of-chiral-aryl-isocyanide-and-achiral-aryl-isocyanide
#7
Xinwen Yan, Shaowen Zhang, Pengfei Zhang, Xiaolu Wu, An Liu, Ge Guo, Yuping Dong, Xiaofang Li
Commercially available [Ph3C][B(C6F5)4] serves as a highly efficient, metal-free, and single-component initiator not only for carbocationic polymerization of polar and bulky aryl isocyanides with extremely high activity up to 1.2 × 107 g of polymer/(molcat.·h) but also for helical-sense-selective polymerization of chiral aryl isocyanides and copolymerization with achiral aryl isocyanide, affording high molecular weight functional poly(aryl isocyanide)s with good solubility, AIE nature, and/or one-handed helical conformation...
May 13, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29750387/enhancing-temporal-control-and-enabling-chain-end-modification-in-photoregulated-cationic-polymerizations-by-using-ir-based-catalysts
#8
Veronika Kottisch, Michael J Supej, Brett P Fors
Gaining temporal control over chain growth is a key challenge in the enhancement of controlled living polymerizations. Though research on photocontrolled polymerizations is still in its infancy, it has already proven useful in the development of previously inaccessible materials. Our research group recently extended photocontrol to cationic polymerizations using 2,4,6-triarylpyrylium salts as photocatalysts. Despite the ability to stop the polymerization for a short amount of time, we observed monomer conversion over long dark periods...
May 11, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29744456/facially-amphiphilic-polyionene-biocidal-polymers-derived-from-lithocholic-acid
#9
Mitra S Ganewatta, Md Anisur Rahman, Louis Mercado, Tinom Shokfai, Alan W Decho, Theresa M Reineke, Chuanbing Tang
Bacterial infections have become a global issue that requires urgent attention, particularly regarding to emergence of multidrug resistant bacteria. We developed quaternary amine-containing antimicrobial poly(bile acid)s that contain a hydrophobic core of lithocholic acid in the main-chain. Interestingly, by choosing appropriate monomers, these cationic polymers can form core-shell micelles. These polymers exhibited biocidal activity against both Gram-positive and Gram-negative bacterial species. It is demonstrated that the micelles can deliver hydrophobic antibiotics that functionally have dual antimicrobial activities...
June 2018: Bioactive Materials
https://www.readbyqxmd.com/read/29742347/robust-multilayer-graphene-organic-frameworks-for-selective-separation-of-monovalent-anions
#10
Yan Zhao, Jiajie Zhu, Jian Li, Zhijuan Zhao, Sebastian Ignacio Charchalac Ochoa, Jiangnan Shen, Congjie Gao, Bart Van der Bruggen
The chemical and mechanical stability of graphene nanosheets was used in this work to design a multilayer architecture of graphene, grafted with sulfonated 4,4'- diaminodiphenyl sulfone (SDDS). Quaternized poly (phenylene oxide) (QPPO) was synthesized and mixed with SDDS (rGO-SDDS-rGO@QPPO), yielding a multilayer graphene-organic framework (MGOF) with positive as well as negative functional groups that can be applied as a versatile electro-driven membrane in electrodialysis (ED). Multilayer graphene-organic frameworks are a new class of multilayer structures, with an architecture having a tunable interlayer spacing connected by cationic polymer material...
May 9, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29738245/enzyme-responsive-charge-reversal-polymer-mediated-effective-gene-therapy-for-intraperitoneal-tumors
#11
Nasha Qiu, Jianqing Gao, Qi Liu, Jinqiang Wang, Youqing Shen
Gene therapy has demonstrated effectiveness in many genetic diseases as evidenced by recent clinical applications. Viral vectors have been extensively tested in clinical gene-therapy trials, but nonviral vectors such as cationic polymers or lipids are much less used due to their lower gene-transfection efficiencies. However, the advantages of nonviral vectors, such as easily tailored structures, nonimmunogenetics, and relatively low cost, still drive great efforts to improve their transfection efficiencies...
May 8, 2018: Biomacromolecules
https://www.readbyqxmd.com/read/29737861/molecular-insights-into-the-effects-of-media-drug-and-carrier-drug-interactions-on-ph-responsive-drug-carriers
#12
Ratna S Katiyar, Prateek K Jha
We have performed two sets of all atom Molecular Dynamics (MD) simulations of polyacrylic acid (PAA) oligomers, considered as a model pH-responsive drug carrier. In the first set, multiple oligomers of PAA are simulated in model gastric and intestinal fluids, where the degree of deprotonation of PAA oligomers vary with the medium pH. Since the gastric fluid has a pH substantially lower than intestinal fluid, PAA is relatively lesser ionized in gastric fluid and forms aggregates. In the second set, we simulated multiple oligomers of PAA with multiple molecules of a cationic anticancer drug, Doxorubicin (DOX), for a range of pH values representative of various physiological conditions...
May 8, 2018: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/29734757/capture-of-pb-2-and-cu-2-metal-cations-by-neisseria-meningitidis-type-capsular-polysaccharides
#13
Sujan Ghimire, Pumtiwitt C McCarthy
Heavy metal pollution of water is a significant environmental and public health concern. Current biological strategies for heavy metal removal from water are performed using microbial biopolymers, including polysaccharides, that are already fully formed. This creates limitations in adapting polysaccharides to increase binding affinity for specific metals. We propose that altering the specificity of polysaccharide-producing enzymes could be beneficial to improving metal capture by modified polysaccharides. We assess binding of Cu2+ and Pb2+ metal cations to Neisseria meningitidis -type polysaccharides...
May 5, 2018: Biomolecules
https://www.readbyqxmd.com/read/29732741/an-enzyme-responsive-turn-on-fluorescence-polymeric-superamphiphile-as-a-potential-visualizable-phosphate-prodrug-delivery-vehicle
#14
Xi Yang, Shihong Shen, Li Guo, Jidong Tan, Henxin Lei, Jianghan Wu, Lei Zhao, Tao Xiong, Youshen Wu, Yilong Cheng, Yanfeng Zhang
The development of inexpensive and highly efficient enzyme-responsive polymers has significantly contributed to targeted drug delivery systems. Here, a superamphiphile with a capability of fluorescent dissociation sensing is designed. It is constructed with negatively charged adenosine 5'-triphosphate (ATP) and negatively charged fluorescein diphosphate (FDP), which are used as fluorescence detection, and a cationic diblock copolymer methoxy-poly(ethylene glycol)113 -b-poly(2-dimethyl-aminoethyl methacrylate)70 ...
May 7, 2018: Macromolecular Bioscience
https://www.readbyqxmd.com/read/29729861/on-line-coupling-of-hydrophilic-ionic-liquids-based-polymer-monolith-microextraction-to-capillary-liquid-chromatography-with-amperometric-detection-an-ultrasensitive-residue-analysis-method-for-glycopeptide-antibiotics
#15
Yanxia Tang, Ning Zhang, Bingyu Zhang, Xiaoyun Lei, Xiaoping Wu
A hydrophilic ionic liquids based polymer monolith microextraction (PMME) column (poly(ionic liquid-co-hydroxyethyl methacrylate-co-ethylene dimethacrylate); poly(IL-co-HEMA-co-EDMA)) was prepared for the first time in a capillary and utilized in PMME for the enrichment of glycopeptide antibiotics (GAs), followed by the online coupling analysis of capillary liquid chromatography with amperometric detection (cLC-AD). The prepared monolith exhibited large through pores and good storage stability, as well as a selective extraction machanism for GAs that was attributed to the hydrogen bonding, hydrophilic, electrostatic and π-π interactions between GAs and the imidazolium cations or hydroxyl groups on the surface of absorbent...
April 30, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29723819/optimizing-liposomes-for-delivery-of-bowman-birk-protease-inhibitors-platforms-for-multiple-biomedical-applications
#16
Graziella Anselmo Joanitti, Rupa S Sawant, Vladimir P Torchilin, Sonia Maria de Freitas, Ricardo Bentes Azevedo
One of the major challenges in the administration of therapeutic proteins involves delivery limitations. Liposomes are well-known drug delivery systems (DDS) that have been used to overcome this drawback; nevertheless, low protein entrapment efficiency (EE) still limits their wide biomedical application on a commercial scale. In the present work, different methods for protein entrapment into liposomes were tested in order to obtain tailored DDS platforms for multiple biomedical applications. The protein used as model was the Black-eyed pea Trypsin and Chymotrypsin Inhibitor (BTCI), a member of the Bowman-Birk protease inhibitor family (BBIs), which has been largely explored for its potential application in many biomedical therapies...
April 20, 2018: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/29722968/bimetallic-uranyl-organic-frameworks-supported-by-transition-metal-ion-based-metalloligand-motifs-synthesis-structure-diversity-and-luminescence-properties
#17
Ran Zhao, Lei Mei, Kong-Qiu Hu, Ming Tian, Zhi-Fang Chai, Wei-Qun Shi
A bifunctional ligand, 2,2'-bipyridine-4,4'-dicarboxylic acid (H2 bpdc), has been used in the investigation of constructing bimetallic uranyl organic frameworks (UOFs). Seven novel uranyl-transition metal bimetallic coordination polymers, [(UO2 )Zn(bpdc)2 ] n (1), [Cd(UO2 )(bpdc)2 (H2 O)2 ·2H2 O] n (2), [Cu(UO2 )(bpdc)(SO4 )(H2 O)3 ·2H2 O] n (3), [CuCl(UO2 )(bpdc)(Hbpdc)(H2 O)2 ·H2 O] n (4), [Cu(UO2 )(bpdc)2 (H2 O)] n (5), [Co2 (UO2 )3 (bpdc)6 ] n (6), and [Co3 (UO2 )4 (bpdc)8 (Hbpdc)(H2 O)2 ] n (7), have been successfully constructed through the assembly of various transition-metal salts, uranyl ions, and H2 bpdc ligands under hydrothermal conditions...
May 3, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29722399/intramolecular-and-interfacial-dynamics-of-triarylamine-based-hole-transport-materials
#18
Johannes R Klein, Mirko Scholz, Kawon Oum, Thomas Lenzer
We present steady-state and time-resolved spectroscopic investigations combined with detailed kinetic modelling for the triarylamine derivatives X60 and PTAA which serve as hole transport materials (HTMs) in perovskite solar cells and represent model compounds for organic electronic materials. Photoexcitation of the spiro-fluorene-xanthene X60 populates its S1 state which decays via intersystem crossing (ISC) as well as fluorescence and internal conversion on a nanosecond time scale. Photoexcitation of the PTAA polymer leads to the formation of singlet excitons which relax and migrate in the time regime from a few to about a hundred picoseconds and decay to the ground state with a lifetime of ca...
May 3, 2018: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/29719390/smart-polymeric-nanoparticles-with-ph-responsive-and-peg-detachable-properties-for-co-delivering-paclitaxel-and-survivin-sirna-to-enhance-antitumor-outcomes
#19
Mingji Jin, Guangming Jin, Lin Kang, Liqing Chen, Zhonggao Gao, Wei Huang
Background: The co-delivery of chemotherapeutic agents and small interfering RNA (siRNA) within one cargo can enhance the anticancer outcomes through its synergistic therapeutic effects. Materials and methods: We prepared smart polymeric nanoparticles (NPs) with pH-responsive and poly(ethylene glycol) (PEG)-detachable properties to systemically co-deliver paclitaxel (PTX) and siRNA against survivin gene for lung cancer therapy. The cationic polyethyleneimine-block-polylactic acid (PEI-PLA) was first synthesized and characterized, with good biocompatibility...
2018: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/29718375/influence-of-na-and-mg2-ions-on-rna-structures-studied-with-molecular-dynamics-simulations
#20
Nina M Fischer, Marcelo D Polêto, Jakob Steuer, David van der Spoel
The structure of ribonucleic acid (RNA) polymers is strongly dependent on the presence of, in particular Mg2+ cations to stabilize structural features. Only in high-resolution X-ray crystallography structures can ions be identified reliably. Here, we perform molecular dynamics simulations of 24 RNA structures with varying ion concentrations. Twelve of the structures were helical and the others complex folded. The aim of the study is to predict ion positions but also to evaluate the impact of different types of ions (Na+ or Mg2+) and the ionic strength on structural stability and variations of RNA...
April 30, 2018: Nucleic Acids Research
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