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https://www.readbyqxmd.com/read/28103491/chemically-activated-carbon-from-lignocellulosic-wastes-for-heavy-metal-wastewater-remediation-effect-of-activation-conditions
#1
Arunima Nayak, Brij Bhushan, Vartika Gupta, P Sharma
Chemical activation is known to induce specific surface features of porosity and functionality which play a definite role in enhancing the adsorptive potential of the developed activated carbons. Different conditions of temperature, time, reagent type and impregnation ratio were applied on sawdust precursor and their effect on the physical, surface chemical features and finally on the adsorption potential of the developed activated carbons were analysed. Under activation conditions of 600°C, 1hr, 1:0.5 ratio, ZnCl2 impregnated carbon (CASD_ZnCl2) resulted in microporosity while KOH impregnation (CASD_KOH) yielded a carbon having a wider pore size distribution...
January 10, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28103437/solvation-reaction-field-at-the-interface-measured-by-vibrational-sum-frequency-generation-spectroscopy
#2
Shayne A Sorenson, Joel G Patrow, Jahan M Dawlaty
Interfacial electric fields are important in several areas of chemistry, materials sciences, and device physics. However, they are poorly understood, partly because they are difficult to measure directly and model accurately. We present both a spectroscopic experimental investigation and a theoretical model for the interfacial field at the junction of a conductor and a dielectric. First, we present Vibrational Sum Frequency Generation (VSFG) results of the nitrile (CN) stretch of 4-mercaptobenzonitrile (4-MBN) covalently attached to a gold surface and in contact with a variety of liquid dielectrics...
January 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28102692/de-novo-assembly-of-highly-substituted-morpholines-and-piperazines
#3
Pravin Patil, Rudrakshula Madhavachary, Katarzyna Kurpiewska, Justyna Kalinowska-Tłuścik, Alexander Dömling
The morpholine and piperazine with their remarkable physical and biochemical properties are popular heterocycles in organic and medicinal chemistry used in rational property design. However, in the majority of cases these rings are added to an existing molecule in a building block approach thus limiting their substitution pattern and diversity. Here we introduce a versatile de novo synthesis of the morpholine and piperazine rings using multicomponent reaction chemistry. The large scale amenable building blocks can be further substituted at up to four positions, making this a very versatile scaffold synthesis strategy...
January 19, 2017: Organic Letters
https://www.readbyqxmd.com/read/28102668/adventures-in-reactive-intermediate-chemistry-a-perspective-and-retrospective
#4
Robert A Moss
I review aspects of my research on reactive intermediates, specifically the physical organic chemistry of carbenes and carbocations. The topics treated include carbenoids, carbenic philicity, absolute rates of carbene/alkene additions, the diazirine exchange reaction and derived carbenes, carbene equilibria, carbocations from diazotates, and carbocations from alkoxychlorocarbenes. The essay concludes with observations on the protean nature of physical organic chemistry.
January 19, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28098316/a-family-of-mechanically-adaptive-supramolecular-graphene-oxide-poly-ethylenimine-hydrogels-from-aqueous-assembly
#5
Chao Wang, Yipin Duan, Nicole S Zacharia, Bryan D Vogt
Composite hydrogels containing graphene oxide (GO) offer advantageous mechanical properties, but tuning these properties generally requires the synthesis of new hydrogels or if the hydrogel is thermally responsive, utilization of a chemistry determined temperature window. Here, we demonstrate a simple route to generate a family of GO-based hydrogels from aqueous solution based assembly of GO with polycationic poly(ethylenimine), PEI, without any secondary chemical crosslinking. Tuning the ratio of GO : PEI during the assembly produces a family of hydrogels that responds to mechanical compression by irreversibly altering their equilibrium water content and mechanical properties in a controllable manner...
January 18, 2017: Soft Matter
https://www.readbyqxmd.com/read/28093991/cancer-nanotechnology-recent-trends-and-developments-in-strategies-for-targeting-cancer-cells-to-improve-cancer-imaging-and-treatment
#6
Jingyao Xu, Xiaoling Zhou, Yifei Li, Yudan Tian
Nanotechnology is a multidisciplinary field, which have the potential to cover applications in many subjects such as biology, chemistry and physics. The combined efforts of these subjects can lead to the successful engineering of nanodevices and nanovectors for targeted delivery and sensing/detection of cancer cells/tissues. The modulation of nanomaterials at surface and bulk level further adds value to this technology and develop strategies for early detection of precancerous and malignant cells from biological fluids...
January 16, 2017: Current Drug Metabolism
https://www.readbyqxmd.com/read/28092833/study-of-molecular-interactions-between-chitosan-and-vi-antigen
#7
Natália de Farias Silva, Raimundo Lopes da Silva, Kalene de Oliveira Almeida, Antônio Edilson Sousa do Nascimento-Júnior, Davi do Socorro Barros Brasil, José Otávio Carréra Silva-Júnior, Francisco Martins Teixeira, Roseane Maria Ribeiro-Costa
Chitosan has attracted much interest due to its special physical and chemical properties related to drug administration. Nanoparticles delivery systems from Vi Antigen are a promising approach in the struggle against typhoid fever. In this paper, we reported the obtainment and the characterization of Vi Antigen by Infrared spectroscopy as well as Molecular Modeling and Computational Chemistry studies of the Chitosan-Vi Antigen interaction through theoretical models. The results of the theoretical and experimental Infrared spectroscopy showed important bands related to N-Acetyl and O-Acetyl groups present in Vi Antigen...
December 31, 2016: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28092430/optimal-reactivity-and-improved-self-healing-capability-of-structurally-dynamic-polymers-grafted-on-janus-nanoparticles-governed-by-chain-stiffness-and-spatial-organization
#8
Guoxi Xu, Zihan Huang, Pengyu Chen, Tianqi Cui, Xinghua Zhang, Bing Miao, Li-Tang Yan
Structurally dynamic polymers are recognized as a key potential to revolutionize technologies ranging from design of self-healing materials to numerous biomedical applications. Despite intense research in this area, optimizing reactivity and thereby improving self-healing ability at the most fundamental level pose urgent issue for wider applications of such emerging materials. Here, the authors report the first mechanistic investigation of the fundamental principle for the dependence of reactivity and self-healing capabilities on the properties inherent to dynamic polymers by combining large-scale computer simulation, theoretical analysis, and experimental discussion...
January 16, 2017: Small
https://www.readbyqxmd.com/read/28091741/chemical-physical-and-biological-factors-shape-littoral-invertebrate-community-structure-in-coal-mining-end-pit-lakes
#9
Andreas Luek, Joseph B Rasmussen
Aquatic invertebrates form the base of the consumer food web in lakes. In coal-mining end-pit lakes, invertebrates are exposed to an environment with potentially challenging physical and chemical features. We hypothesized that the physical and chemical features of end-pit lakes reduce critical littoral habitat and thus reduce invertebrate diversity, thereby limiting the potential for these lakes to be naturalized. We used a multivariate approach using principle component analysis and redundancy analysis to study relationships between invertebrate community structure, habitat features, and water quality in five end-pit lakes and five natural lakes in the Rocky Mountain foothills of west-central Alberta, Canada...
January 13, 2017: Environmental Management
https://www.readbyqxmd.com/read/28088667/cell-laden-hydrogels-for-osteochondral-and-cartilage-tissue-engineering
#10
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/28088572/bcs-class-iv-drugs-highly-notorious-candidates-for-formulation-development
#11
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/28088081/lead-pb-2-and-copper-cu-2-remediation-from-water-using-superparamagnetic-maghemite-%C3%AE-fe2o3-nanoparticles-synthesized-by-flame-spray-pyrolysis-fsp
#12
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/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/28078990/mass-spectrometry-imaging-in-nanomedicine-unraveling-the-potential-of-msi-for-the-detection-of-nanoparticles-in-neuroscience
#14
Florian Py Barré, Ron Ma Heeren, Nina Ogrinc Potočnik
Mass spectrometry imaging (MSI) can uniquely detect thousands of compounds allowing both their identification and localization within biological tissue samples. MSI is an interdisciplinary science that crosses the borders of physics, chemistry and biology, and enables local molecular analysis at a broad range of length scales: From the subcellular level to whole body tissue sections. The spatial resolution of some mass spectrometers now allows nano-scale research, crucial for studies in nanomedicine. Recent developments in MSI have enabled the optimization and localization of drug delivery with nanoparticles within the body and in specific organs such as kidney, liver and brain...
January 11, 2017: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/28078627/nanostructured-materials-synthesis-using-ultrasound
#15
REVIEW
Jordan J Hinman, Kenneth S Suslick
Recent applications of ultrasound to the production of nanostructured materials are reviewed. Sonochemistry permits the production of novel materials or provides a route to known materials without the need for high bulk temperatures, pressures, or long reaction times. Both chemical and physical phenomena associated with high-intensity ultrasound are responsible for the production or modification of nanomaterials. Most notable are the consequences of acoustic cavitation: the formation, growth, and implosive collapse of bubbles, and can be categorized as primary sonochemistry (gas-phase chemistry occurring inside collapsing bubbles), secondary sonochemistry (solution-phase chemistry occurring outside the bubbles), and physical modifications (caused by high-speed jets, shockwaves, or inter-particle collisions in slurries)...
February 2017: Topics in Current Chemistry (Journal)
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/28077807/folding-of-apomyoglobin-analysis-of-transient-intermediate-structure-during-refolding-using-quick-hydrogen-deuterium-exchange-and-nmr
#17
Chiaki Nishimura
The structures of apomyoglobin folding intermediates have been widely analyzed using physical chemistry methods including fluorescence, circular dichroism, small angle X-ray scattering, NMR, mass spectrometry, and rapid mixing. So far, at least two intermediates (on sub-millisecond- and millisecond-scales) have been demonstrated for apomyoglobin folding. The combination of pH-pulse labeling and NMR is a useful tool for analyzing the kinetic intermediates at the atomic level. Its use has revealed that the latter-phase kinetic intermediate of apomyoglobin (6 ms) was composed of helices A, B, G and H, whereas the equilibrium intermediate, called the pH 4 molten-globule intermediate, was composed mainly of helices A, G and H...
2017: Proceedings of the Japan Academy. Series B, Physical and Biological Sciences
https://www.readbyqxmd.com/read/28075405/the-role-of-reactive-oxygen-species-ros-in-the-biological-activities-of-metallic-nanoparticles
#18
REVIEW
Ahmed Abdal Dayem, Mohammed Kawser Hossain, Soo Bin Lee, Kyeongseok Kim, Subbroto Kumar Saha, Gwang-Mo Yang, Hye Yeon Choi, Ssang-Goo Cho
Nanoparticles (NPs) possess unique physical and chemical properties that make them appropriate for various applications. The structural alteration of metallic NPs leads to different biological functions, specifically resulting in different potentials for the generation of reactive oxygen species (ROS). The amount of ROS produced by metallic NPs correlates with particle size, shape, surface area, and chemistry. ROS possess multiple functions in cellular biology, with ROS generation a key factor in metallic NP-induced toxicity, as well as modulation of cellular signaling involved in cell death, proliferation, and differentiation...
January 10, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28068053/surface-modification-of-gold-nanoparticles-with-small-molecules-for-biochemical-analysis
#19
Yiping Chen, Yunlei Xianyu, Xingyu Jiang
As one of the major tools for and by chemical science, biochemical analysis is becoming increasingly important in fields like clinical diagnosis, food safety, environmental monitoring, and the development of chemistry and biochemistry. The advancement of nanotechnology boosts the development of analytical chemistry, particularly the nanoparticle (NP)-based approaches for biochemical assays. Functional NPs can greatly improve the performance of biochemical analysis because they can accelerate signal transduction, enhance the signal intensity, and enable convenient signal readout due to their unique physical and chemical properties...
January 9, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28060511/cluster-model-studies-of-anion-and-molecular-specificities-via-electrospray-ionization-photoelectron-spectroscopy
#20
Xue-Bin Wang
Ion specificity, a widely observed macroscopic phenomenon in condensed phases and at interfaces, is a fundamental chemical physics issue. Herein we report our recent studies of such effects using cluster models in an "atom-by-atom" and "molecule-by-molecule" fashion not possible with the condensed-phase methods. We use electrospray ionization (ESI) to generate molecular and ionic clusters to simulate key molecular entities involved in local binding regions, and characterize them employing negative ion photoelectron spectroscopy (NIPES)...
January 6, 2017: Journal of Physical Chemistry. A
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