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https://www.readbyqxmd.com/read/28088667/cell-laden-hydrogels-for-osteochondral-and-cartilage-tissue-engineering
#1
REVIEW
Jingzhou Yang, Yu Shrike Zhang, Kan Yue, Ali Khademhosseini
: Despite tremendous advances in the field of regenerative medicine, it still remains challenging to repair the osteochondral interface and full-thickness articular cartilage defects. This inefficiency largely originates from the lack of appropriate tissue engineered artificial matrices that can replace the damaged regions and promote tissue regeneration. Hydrogels are emerging as a promising class of biomaterials for both soft and hard tissue regeneration. Many critical properties of hydrogels, such as mechanical stiffness, elasticity, water content, bioactivity, and degradation, can be rationally designed and conveniently tuned by proper selection of the material and chemistry...
January 11, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28088631/an-esipt-based-two-photon-fluorescent-probe-detection-of-hydrogen-peroxide-in-live-cells-and-tissues
#2
Liyi Zhou, Yongbo Peng, Qianqian Wang, Qinlu Lin
A variety of diseases associated with human aging, which have a strong oxidative stress, but connecting age-related diseases and oxidative stress of the basic molecular mechanisms still insufficiently understood. Oxidative stress origins from the unregulated production of reactive oxygen species (ROS), and oxidative damaging to tissues and organs from subsequent oxidation-reduction chemistry by cellular mismanagement. In particular, H2O2 is a major by-product of ROS in live organisms and a common marker for oxidative stress, and its dynamic equilibrium can have various physiological and pathological consequences...
January 9, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28088572/bcs-class-iv-drugs-highly-notorious-candidates-for-formulation-development
#3
REVIEW
Rohan Ghadi, Neha Dand
BCS class IV drugs (e.g., amphotericin B, furosemide, acetazolamide, ritonavir, paclitaxel) exhibit many characteristics that are problematic for effective oral and per oral delivery. Some of the problems associated include low aqueous solubility, poor permeability, erratic and poor absorption, inter and intra subject variability and significant positive food effect which leads to low and variable bioavailability. Also, most of the class IV drugs are substrate for P-glycoprotein (low permeability) and substrate for CYP3A4 (extensive pre systemic metabolism) which further potentiates the problem of poor therapeutic potential of these drugs...
January 11, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28088529/effect-of-water-chemistry-on-disinfection-by-product-formation-in-the-complex-surface-water-system
#4
Rongjie Hao, Yan Zhang, Tingting Du, Li Yang, Adeyemi S Adeleye, Yao Li
The relationship between the disinfection by-products (DBPs) formed with chlorination and chloramination techniques and the water chemistry of Haihe River was compared. Samples were collected at 28 different points within the mainstream and tributaries of the river. The DBPs investigated include trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs), and trichloronitromethane. THMs formed when the samples were chlorinated mostly exceeded 100 and 600 μg/L in the mainstream and tributaries and in the estuary, respectively...
December 8, 2016: Chemosphere
https://www.readbyqxmd.com/read/28088151/phase-transition-of-a-symmetric-diblock-copolymer-induced-by-nanorods-with-different-surface-chemistry
#5
Yu-Qi Guo, Jun-Xing Pan, Min-Na Sun, Jin-Jun Zhang
We investigate the phase transition of a symmetric diblock copolymer induced by nanorods with different surface chemistry. The results demonstrate that the system occurs the phase transition from a disordered structure to ordered parallel lamellae and then to the tilted layered structure as the number of rods increases. The dynamic evolution of the domain size and the order parameter of the microstructure are also examined. Furthermore, the influence of rod property, rod-phase interaction, rod-rod interaction, rod length, and polymerization degree on the behavior of the polymer system is also investigated systematically...
January 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28088137/forces-on-nuclei-moving-on-autoionizing-molecular-potential-energy-surfaces
#6
Nimrod Moiseyev
Autoionization of molecular systems occurs in diatomic molecules and in small biochemical systems. Quantum chemistry packages enable calculation of complex potential energy surfaces (CPESs). The imaginary part of the CPES is associated with the autoionization decay rate, which is a function of the molecular structure. Molecular dynamics simulations, within the framework of the Born-Oppenheimer approximation, require the definition of a force field. The ability to calculate the forces on the nuclei in bio-systems when autoionization takes place seems to rely on an understanding of radiative damages in RNA and DNA arising from the release of slow moving electrons which have long de Broglie wavelengths...
January 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28088081/lead-pb-2-and-copper-cu-2-remediation-from-water-using-superparamagnetic-maghemite-%C3%AE-fe2o3-nanoparticles-synthesized-by-flame-spray-pyrolysis-fsp
#7
Shalini Rajput, Lok P Singh, Charles U Pittman, Dinesh Mohan
Superparamagnetic maghemite (γ-Fe2O3) nanoparticles of controllable morphology were successfully synthesized using a flame spray pyrolysis (FSP) technique. Their physico-chemical properties, size, morphology, and surface chemistries were determined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), selected area electron diffraction patterns (SAED), SEM-EDX, scanning electron microscopy (SEM), and pHZPC(6.3). Elemental contents before and after adsorption were identified using energy dispersive X-ray fluorescence (ED-XRF), energy dispersive X-ray analysis (EDX) and elemental mapping...
November 27, 2016: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28087422/nano-qsar-in-cell-biology-model-of-cell-viability-as-a-mathematical-function-of-available-eclectic-data
#8
Alla P Toropova, Andrey A Toropov
The prediction of biochemical endpoints is an important task of the modern medicinal chemistry, cell biology, and nanotechnology. Simplified molecular input-line entry system (SMILES) is a tool for representation of the molecular structure. In particular, SMILES can be used to build up the quantitative structure - property / activity relationships (QSPRs/QSARs). The QSPR/QSAR is a tool to predict an endpoint for a new substance, which has not been examined in experiment. Quasi-SMILES are representation of eclectic data related to an endpoint...
January 10, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28087127/the-route-from-problem-to-solution-in-multistep-continuous-flow-synthesis-of-pharmaceutical-compounds
#9
Péter Bana, Róbert Örkényi, Klára Lövei, Ágnes Lakó, György István Túrós, János Éles, Ferenc Faigl, István Greiner
Recent advances in the field of continuous flow chemistry allow the multistep preparation of complex molecules such as APIs (Active Pharmaceutical Ingredients) in a telescoped manner. Numerous examples of laboratory-scale applications are described, which are pointing towards novel manufacturing processes of pharmaceutical compounds, in accordance with recent regulatory, economical and quality guidances. The chemical and technical knowledge gained during these studies is considerable; nevertheless, connecting several individual chemical transformations and the attached analytics and purification holds hidden traps...
December 29, 2016: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28080221/molecular-mechanisms-of-antisense-oligonucleotides
#10
Stanley T Crooke
In 1987, when I became interested in the notion of antisense technology, I returned to my roots in RNA biochemistry and began work to understand how oligonucleotides behave in biological systems. Since 1989, my research has focused primarily on this topic, although I have been involved in most areas of research in antisense technology. I believe that the art of excellent science is to frame large important questions that are perhaps not immediately answerable with existing knowledge and methods, and then conceive a long-term (multiyear) research strategy that begins by answering the most pressing answerable questions on the path to the long-term goals...
January 12, 2017: Nucleic Acid Therapeutics
https://www.readbyqxmd.com/read/28079196/ultra-fast-charge-migration-competes-with-proton-transfer-in-the-early-chemistry-of-h2o%C3%AB
#11
Furong Wang, Uli Schmidhammer, Aurélien de La Lande, Mehran Mostafavi
Oxidation by the ultra-short lived radical cation of water, H2O˙(+), can potentially take place at the interface of water and numerous heterogeneous systems involved in radiation therapy, energy and environmental industries. The oxidation processes induced by H2O˙(+) can be mimicked in highly concentrated solutions where the nearest neighbors of H2O˙(+) may be molecules other than water. The reactivity of H2O˙(+) and D2O˙(+) is probed in hydrogenated and deuterated sulfuric acid solutions of various concentrations...
January 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28079160/tempo-of-magma-degassing-and-the-genesis-of-porphyry-copper-deposits
#12
Cyril Chelle-Michou, Bertrand Rottier, Luca Caricchi, Guy Simpson
Porphyry deposits are copper-rich orebodies formed by precipitation of metal sulphides from hydrothermal fluids released from magmatic intrusions that cooled at depth within the Earth's crust. Finding new porphyry deposits is essential because they are our largest source of copper and they also contain other strategic metals including gold and molybdenum. However, the discovery of giant porphyry deposits is hindered by a lack of understanding of the factors governing their size. Here, we use thermal modelling and statistical simulations to quantify the tempo and the chemistry of fluids released from cooling magmatic systems...
January 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28079027/the-properties-of-ultrapure-delafossite-metals
#13
A P Mackenzie
Although they were first synthesized in chemistry laboratories nearly fifty years ago, the physical properties of the metals PdCoO2, PtCoO2 and PdCrO2 have only more recently been studied in detail. The delafossite structure contains triangular co-ordinated atomic layers, and electrical transport in the delafossite metals is strongly 2D. Their most notable feature is their in-plane conductivity, which is amazingly high for oxide metals. At room temperature, the conductivity of non-magnetic PdCoO2 and PtCoO2 is higher per carrier than those of any alkali metal and even the most conductive elements, copper and silver...
January 12, 2017: Reports on Progress in Physics
https://www.readbyqxmd.com/read/28078952/recent-advances-in-green-nanoparticulate-systems-for-drug-delivery-efficient-delivery-and-safety-concern
#14
Pik-Ling Lam, Wai-Yeung Wong, Zhaoxiang Bian, Chung-Hin Chui, Roberto Gambari
Nanotechnology manipulates therapeutic agents at the nanoscale for the development of nanomedicines. However, there are current concerns over nanomedicines, mainly related to the possible toxicity of nanomaterials used for health medications. Due to their small size, they can enter the human body more readily than larger sized particles. Green chemistry encompasses the green synthesis of drug-loaded nanoparticles by reducing the use of hazardous materials in the synthesis process, thus reducing the adverse health impacts of pharmaceutics...
January 12, 2017: Nanomedicine
https://www.readbyqxmd.com/read/28078889/quantification-of-free-polyelectrolytes-present-in-colloidal-suspension-revealing-a-source-of-toxic-responses-for-polyelectrolyte-wrapped-gold-nanoparticles
#15
Tian A Qiu, Marco D Torelli, Ariane M Vartanian, Nathan B Rackstraw, Joseph T Buchman, Lisa M Jacob, Catherine J Murphy, Robert J Hamers, Christy L Haynes
Polyelectrolyte (PE) wrapping of colloidal nanoparticles (NPs) is a standard method to control NP surface chemistry and charge. Because excess polyelectrolytes are usually employed in the surface modification process, it is critical to evaluate different purification strategies to obtain a clean final product and thus avoid ambiguities in the source of effects on biological systems. In this work, 4 nm diameter gold nanoparticles (AuNPs) were wrapped with 15 kDa poly(allylamine hydrochloride) (PAH), and three purification strategies were applied: (a) diafiltration or either (b) one round or (c) two rounds of centrifugation...
January 10, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28078499/carbonaceous-chondrite-meteorites-the-chronicle-of-a-potential-evolutionary-path-between-stars-and-life
#16
Sandra Pizzarello, Everett Shock
The biogenic elements, H, C, N, O, P and S, have a long cosmic history, whose evolution can still be observed in diverse locales of the known universe, from interstellar clouds of gas and dust, to pre-stellar cores, nebulas, protoplanetary discs, planets and planetesimals. The best analytical window into this cosmochemical evolution as it neared Earth has been provided so far by the small bodies of the Solar System, some of which were not significantly altered by the high gravitational pressures and temperatures that accompanied the formation of larger planets and may carry a pristine record of early nebular chemistry...
January 11, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28078409/determination-of-molecular-size-parameters-and-quantification-of-polyacrylic-acid-by-high-performance-size-exclusion-chromatography-with-triple-detection
#17
Jean-François Cotte, Afifa Bouadam, Agathe Sordoillet, Isabelle Jaudinaud, Véronique Chambon, Philippe Talaga
Synthetic polyelectrolytes are a broad class of vaccine adjuvants. Among them, polyacrylic acid (PAA), a polyanionic polymer, is currently evaluated by Sanofi Pasteur. As chain length is considered to be a critical quality attribute for adjuvant properties of PAA, measurement of precise and accurate molecular size parameters is important for these polymers. In the field of synthetic polymer chemistry, methods for determination of molecular size parameters are well defined. Specifically, high performance size-exclusion chromatography (HPSEC) with multi-detection system is a method of choice...
January 11, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28075366/stepwise-protecting-group-free-synthesis-of-4-rotaxanes
#18
James E M Lewis, Joby Winn, Stephen M Goldup
Despite significant advances in the last three decades towards high yielding syntheses of rotaxanes, the preparation of systems constructed from more than two components remains a challenge. Herein we build upon our previous report of an active template copper-catalyzed azide-alkyne cycloaddition (CuAAC) rotaxane synthesis with a diyne in which, following the formation of the first mechanical bond, the steric bulk of the macrocycle tempers the reactivity of the second alkyne unit. We have now extended this approach to the use of 1,3,5-triethynylbenzene in order to successively prepare [2]-, [3]- and [4]rotaxanes without the need for protecting group chemistry...
January 9, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28072539/extension-of-the-reaxff-combustion-force-field-towards-syngas-combustion-and-initial-oxidation-kinetics
#19
Chowdhury Ashraf, Adri C T van Duin
A detailed insight of key reactive events related to oxidation and pyrolysis of hydrocarbon fuels further enhances our understanding of combustion chemistry. Though comprehensive kinetic models are available for smaller hydrocarbons (typically C3 or lower), developing and validating reaction mechanisms for larger hydrocarbons is a daunting task, due to the complexity of their reaction networks. The ReaxFF method provides an attractive computational method to obtain reaction kinetics for complex fuel and fuel mixtures, providing an accuracy approaching ab-initio based methods, but with a significantly lower computational expense...
January 10, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28071663/covalent-modification-of-pericardial-patches-for-sustained-rapamycin-delivery-inhibits-venous-neointimal-hyperplasia
#20
Hualong Bai, Jung Seok Lee, Elizabeth Chen, Mo Wang, Ying Xing, Tarek M Fahmy, Alan Dardik
Prosthetic grafts and patches are commonly used in cardiovascular surgery, however neointimal hyperplasia remains a significant concern, especially under low flow conditions. We hypothesized that delivery of rapamycin from nanoparticles (NP) covalently attached to patches allows sustained site-specific delivery of therapeutic agents targeted to inhibit localized neointimal hyperplasia. NP were covalently linked to pericardial patches using EDC/NHS chemistry and could deliver at least 360 ng rapamycin per patch without detectable rapamycin in serum; nanoparticles were detectable in the liver, kidney and spleen but no other sites within 24 hours...
January 10, 2017: Scientific Reports
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