Read by QxMD icon Read

Organic chemistry*

Mohamad S Kodaimati, Kevin P McClelland, Chen He, Shichen Lian, Yishu Jiang, Zhengyi Zhang, Emily A Weiss
Colloidal semiconductor nanocrystals, or "quantum dots" (QDs), have several optical and chemical properties that give them the potential to enable nonincremental increases in the efficiencies of many types of photocatalytic reactions relevant for energy conversion and organic synthesis. Colloidal photocatalysts have many desirable characteristics of both heterogeneous and homogeneous catalysts but come with their own particular set of challenges. This viewpoint outlines some of the obstacles one first encounters when driving reactions with these colloids and offers some strategies for overcoming these obstacles, including ways to extend their excited state lifetimes, prevent corrosion by photogenerated holes, and choose a surface chemistry and buffering system for maximum colloidal stability over a range of environmental conditions...
March 21, 2018: Inorganic Chemistry
Yunfang Jia, Fang Li
Functional nucleic acids (FNAs) are promising sensing elements, extensive interests are excited to integrate FNAs with transducers for biochemical assays. However, efforts for FNAs modified light-addressable-potentiometric-sensor (FNA-LAPS) are rarely reported. LAPS is a versatile transducer with electrolyte-insulator-semiconductor (EIS) structure, can respond almost any surface electronic deviations. Herein, organized studies for FNA-LAPS including experiments, theoretical derivations and MEDICI (Synopsys®) simulations, are presented using Pb2+ -DNAzyme GR-5 and Ag+ -aptamer as proof-of-concepts, which are typical FNAs with distinctive sensing strategies...
March 21, 2018: Analytical Chemistry
Marine Cotte, Tiphaine Fabris, Juliette Langlois, Ludovic Bellot-Gurlet, Françoise Ploye, Natalie Coural, Clotilde Boust, Jean-Paul Gandolfo, Thomas Galifot, Jean Susini
Louis Ducos du Huron (1837-1920) dedicated his entire life to the elaboration of physical-chemical processes for color photography. This study aimed at highlighting his unique contribution to three-color printing through 1) an in-depth review of the many protocols he published and 2) the synchrotron-based IR and X-ray microanalysis of fragments sampled in three artworks. Ducos du Hauron's method relied on the preparation and assembly of three monochromes (red, blue, yellow). This study brings to light complex multistep recipes based on photochemistry (carbon print), organic, and inorganic chemistry...
March 20, 2018: Angewandte Chemie
Thomas J Penfold, Etienne Gindensperger, Chantal Daniel, Christel M Marian
Intersystem crossing (ISC), formally forbidden within nonrelativistic quantum theory, is the mechanism by which a molecule changes its spin state. It plays an important role in the excited state decay dynamics of many molecular systems and not just those containing heavy elements. In the simplest case, ISC is driven by direct spin-orbit coupling between two states of different multiplicities. This coupling is usually assumed to remain unchanged by vibrational motion. It is also often presumed that spin-allowed radiationless transitions, i...
March 20, 2018: Chemical Reviews
Żaneta Bargańska, Dimitra Lambropoulou, Jacek Namieśnik
Bumblebees play an important role in the pollination process of many crops and flowers. Therefore, taking action to protect and assess the impact of pesticides on these insects is fully justified. Pesticides may cause mortality and also sub-lethal effects that are not always directly visible. Bumblebees, like honeybees, can be used as indicators for environmental monitoring contamination. Two approaches are mainly used for the determination of pesticide residues in pollinating insects: a toxicological test (to know effects) and multi-stage analytical methodologies (to know exposure)...
March 20, 2018: Critical Reviews in Analytical Chemistry
Melissa M Galey, Laura M Sanchez
Microbial communities contribute to a wide variety of biological functions in hosts and have the ability to specifically influence the health of those organisms through production of specialized metabolites. However, the structures or molecular mechanisms related to health or disease in host-microbe interactions represent a knowledge gap. In order to close this gap, we propose that a combinatory approach, pulling from microbiology and analytical chemistry, be considered to investigate these interactions so as to gain a better understanding of the chemistry being produced...
March 2018: MSystems
Çinel Köksal Karayildirim, Mustafa Kotmakçi, Erkan Halay, Kadir Ay, Yücel Başpinar
5-Fluorouracil is one of the first line drugs for the systemic therapy of solid tumors like breast, colorectal, oesophageal, stomach, pancreatic, head and neck. It could be shown that sugars can improve the absorption across cell membranes and can help to bypass some pharmacokinetic problems. Carbohydrates as most common organic molecules are an important issue of plant and animal metabolisms. They are non toxic and have important duties in the body like participating in DNA and RNA synthesis and being responsible for energy production...
March 2018: Saudi Pharmaceutical Journal: SPJ: the Official Publication of the Saudi Pharmaceutical Society
Kateryna Zhalnina, Katherine B Louie, Zhao Hao, Nasim Mansoori, Ulisses Nunes da Rocha, Shengjing Shi, Heejung Cho, Ulas Karaoz, Dominique Loqué, Benjamin P Bowen, Mary K Firestone, Trent R Northen, Eoin L Brodie
Like all higher organisms, plants have evolved in the context of a microbial world, shaping both their evolution and their contemporary ecology. Interactions between plant roots and soil microorganisms are critical for plant fitness in natural environments. Given this co-evolution and the pivotal importance of plant-microbial interactions, it has been hypothesized, and a growing body of literature suggests, that plants may regulate the composition of their rhizosphere to promote the growth of microorganisms that improve plant fitness in a given ecosystem...
March 19, 2018: Nature Microbiology
Ning Guo, Rémi Maurice, David Teze, Jérôme Graton, Julie Champion, Gilles Montavon, Nicolas Galland
The importance of halogen bonds-highly directional interactions between an electron-deficient σ-hole moiety in a halogenated compound and an acceptor such as a Lewis base-is being increasingly recognized in a wide variety of fields from biomedicinal chemistry to materials science. The heaviest halogens are known to form stronger halogen bonds, implying that if this trend continues down the periodic table, astatine should exhibit the highest halogen-bond donating ability. This may be mitigated, however, by the relativistic effects undergone by heavy elements, as illustrated by the metallic character of astatine...
March 19, 2018: Nature Chemistry
Dorina Murgulet, Melissa Trevino, Audrey Douglas, Nicholas Spalt, Xinping Hu, Valeriu Murgulet
We conducted a comprehensive analysis of a variety of geochemical data including total alkalinity (TA), dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), major ions, stable isotopes, and submarine groundwater discharge, to understand biogeochemical and hydrologic processes driving the seasonal to annual estuarine buffering capacity in Nueces Bay, Texas. These measurements, together with statistical analysis and geochemical modeling, show large variability of freshwater influence. TA consumption, common to spring seasons, was mainly driven by CaCO3 precipitation and, to some extent, by aerobic respiration...
March 3, 2018: Science of the Total Environment
Aurélie Fossey-Jouenne, Carine Vergne-Vaxelaire, Anne Zaparucha
Amino alcohols are versatile compounds with a wide range of applications. For instance, they have been used as chiral scaffolds in organic synthesis. Their synthesis by conventional organic chemistry often requires tedious multi-step synthesis processes, with difficult control of the stereochemical outcome. We present a protocol to enzymatically synthetize amino alcohols starting from the readily available L-lysine in 48 h. This protocol combines two chemical reactions that are very difficult to conduct by conventional organic synthesis...
February 16, 2018: Journal of Visualized Experiments: JoVE
Michael S McLachlan, Emma Undeman, Fangyuan Zhao, Matthew MacLeod
Predicting human exposure to an environmental contaminant based on its emissions is one of the great challenges of environmental chemistry. It has been done successfully on a local or regional scale for some persistent organic pollutants. Here we assess whether it can be done at a global scale, using PCB 153 as a test chemical. The global multimedia fate model BETR Global and the human exposure model ACC-HUMAN were employed to predict the concentration of PCB 153 in human milk for 56 countries around the world from a global historical emissions scenario...
March 19, 2018: Environmental Science. Processes & Impacts
Autumn Oczkowski, Bryan Taplin, Richard Pruell, Adam Pimenta, Roxanne Johnson, Jason Grear
Coastal ecosystems are inherently complex and potentially adaptive as they respond to changes in nutrient loads and climate. We documented the role that carbon stable isotope (δ13 C) measurements could play in understanding that adaptation with a series of three Ecostat (i.e., continuous culture) experiments. We quantified linkages among δ13 C, nutrients, carbonate chemistry, primary, and secondary production in temperate estuarine waters. Experimental culture vessels (9.1 L) containing 33% whole and 67% filtered (0...
February 14, 2018: Frontiers in Marine Science
Sidónio C Freitas, Alejandra Correa-Uribe, M Cristina L Martins, Alejandro Pelaez-Vargas
Implant-based therapy is a mature approach to recover the health conditions of patients affected by edentulism. Thousands of dental implants are placed each year since their introduction in the 80s. However, implantology faces challenges that require more research strategies such as new support therapies for a world population with a continuous increase of life expectancy, to control periodontal status and new bioactive surfaces for implants. The present review is focused on self-assembled monolayers (SAMs) for dental implant materials as a nanoscale-processing approach to modify titanium surfaces...
2018: International Journal of Dentistry
Aritri Sanyal, Runa Antony, Gautami Samui, Meloth Thamban
Cryoconite holes (cylindrical melt-holes on the glacier surface) are important hydrological and biological systems within glacial environments that support diverse microbial communities and biogeochemical processes. This study describes retrievable heterotrophic microbes in cryoconite hole water from three geographically distinct sites in Antarctica, and a Himalayan glacier, along with their potential to degrade organic compounds found in these environments. Microcosm experiments (22 days) show that 13-60% of the dissolved organic carbon in the water within cryoconite holes is bio-available to resident microbes...
March 2018: Microbiological Research
André Campaniço, Rui Moreira, Francisca Lopes
Tuberculosis (TB) remains a major health problem worldwide. The infectious agent, Mycobacterium tuberculosis, has a unique ability to survive within the host, alternating between active and latent disease states, and escaping the immune system defences. The extended duration of anti-TB regimens and the increasing prevalence of multidrug- (MDR) and extensively drug-resistant (XDR) M. tuberculosis strains have created an urgent need for new antibiotics active against drug-resistant organisms and that can shorten standard therapy...
March 9, 2018: European Journal of Medicinal Chemistry
V K Sharma, R Mukhopadhyay
Ionic liquids (ILs) are a special class of low-temperature (typically < 100 °C) molten salts, which have huge upsurge interest in the field of chemical synthesis, catalysis, electrochemistry, pharmacology, and biotechnology, mainly due to their highly tunable nature and exceptional properties. However, practical uses of ILs are restricted mainly due to their adverse actions on organisms. Understanding interactions of ILs with biomembrane is prerequisite to assimilate the actions of these ionic compounds on the organism...
March 16, 2018: Biophysical Reviews
Mohamed Bayati, Jingjing Dai, Austin Zambrana, Chloe Rees, Maria Fidalgo de Cortalezzi
Carbon dots are rapidly emerging carbon-based nanomaterials that, due to their growing applications, will inevitable find their way to natural waters; however, their environmental fate is mostly unknown. Carbon dots with different surface functionality were fabricated and characterized by TEM and FT-IR. Their surface charge, given by the zeta potential, and their hydrodynamic diameter in suspension were investigated under a variety of environmentally relevant conditions. The effect of ionic strength was studied in the presence of monovalent (NaCl) and divalent (CaCl2 ) cations, for pH levels from 3 to 11; humic acid was used as a model for dissolved natural organic matter...
March 2018: Journal of Environmental Sciences (China)
Pollyana Trigueiro, Silvia Pedetti, Baptiste Rigaud, Sebastien Balme, Jean-Marc Janot, Ieda M G Dos Santos, Régis Gougeon, Maria G Fonseca, Thomas Georgelin, Maguy Jaber
Wine chemistry inspires and challenges with its complexity and intriguing composition. In this context, the composites based on the use of a model protein, a polyphenol of interest and montmorillonite in a model hydroalcoholic solution have been studied. A set of experimental characterization techniques highlighted the interactions between the organic and the inorganic parts in the composite. The amount of the organic part was determined by ultraviolet-visible (UV-VIS) and thermal analysis. X-ray diffraction (XRD) and transmission electronic microscopy (TEM) informed about the stacking/exfoliation of the layers in the composites...
March 6, 2018: Colloids and Surfaces. B, Biointerfaces
Stéphanie Essafi, Jeremy N Harvey
For condensed-phase reactions, commonly used kinetic models assume that energy exchange from and to solvent molecules is much faster than any reactive steps. However, it is becoming increasingly evident that this does not always hold true. In this work, we use molecular dynamics simulations to explore the timescale for energy transfer between solvent and solute in some typical organic solvents. As a reference, energy transfer between solvent molecules is also considered. The timescale is found to depend most strongly on the identity of the solvent...
March 16, 2018: Journal of Physical Chemistry. A
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"