High purity homo-arm and mikto-arm poly(ethylene glycol) (PEG) stars are successfully prepared by the combination of epoxide ring-openings and azide-alkyne click reactions. First, monohydroxy-PEG was modified via epoxide chemistry to bear one hydroxyl and one azide functionality at the same end. An alkyne-functionalized PEG chain was then coupled to the azide. Subsequently, the remaining hydroxyl could be reactivated to an azide again and again to enable stepwise addition of alkyne-functionalized polymer arms. The use of efficient reactions for this iterative route provides star polymers with an exact number of arms, and a tailorable degree of polymerization for each arm. Detailed characterization confirms the high purity of multi-arm polyethylene glycol products.
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http://dx.doi.org/10.1002/marc.201300623 | DOI Listing |
Small
December 2024
Department of Chemistry & Chemical Biology and the Brockhouse Institute for Materials Research, McMaster University, 1280 Main St. W., Hamilton, ON, L8S 4M1, Canada.
Flexible sensors have garnered significant interest for their potential to monitor human activities and provide valuable feedback for healthcare purposes. Single-walled carbon nanotubes (SWNTs) are promising materials for these applications but suffer from issues of poor purity and solubility. Dispersing SWNTs with conjugated polymers (CPs) enhances solution processability, yet the polymer sidechains can insulate the SWNTs, limiting the sensor's operating voltage.
View Article and Find Full Text PDFTalanta
December 2024
Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan, 430074, China. Electronic address:
The mortality rate of tumor is still very high till now. Circulating tumor cells (CTCs) are the major culprit of high cancer mortality. To improve survival rate of cancer patients, real-time monitoring and quantitative detection of CTCs are of indescribable value.
View Article and Find Full Text PDFFront Biosci (Elite Ed)
November 2024
Food Science Department, Agriculture College, Basrah University, 61001 Basrah, Iraq.
Background: Flavonoids are among the most important compounds found in plants, since laboratory studies have shown them to be a daily requirement in human diets due to their various health benefits. Therefore, this study focused on extracting, purifying, and measuring the antioxidant activity of the flavonoid quercetin, which is widely found in plants and possesses a variety of biological activities, from different plant sources.
Methods: The extraction of quercetin was performed using several methods (chemical, physical, and enzymatic) and several extraction solutions (water, ethanol, and chloroform) from several plants (spinach, dill, Onion Skin, , sumac, digalkhasab chemri, and leelwi chemri).
JACS Au
December 2024
Shanghai Key Laboratory for R&D and Application of Metallic Functional Materials, Institute of New Energy for Vehicles, School of Materials Science and Engineering, Tongji University, 201804, Shanghai, China.
For the aim of achieving the carbon-free energy scenario, green hydrogen (H) with non-CO emission and high energy density is regarded as a potential alternative to traditional fossil fuels. Over the last decades, significant breakthroughs have been realized on the alkaline hydrogen evolution reaction (HER), which is a fundamental advancement and efficient process to generate high-purity H in the laboratory. Based on this, the development of the practical industry-oriented anion exchange membrane water electrolyzer (AEMWE) is on the rise, showing competitiveness with the incumbent megawatt-scale H production technologies.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic.
Cyclin-dependent kinases (CDKs) regulate cell cycle progression and transcription. CDK7 plays a pivotal role in cell division and proliferation, and the CDK7 gene often exhibits mutations or copy number loss in cancer. Pharmacological targeting of CDK7 has been proposed as a cancer treatment strategy and several inhibitors are currently in clinical trials.
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