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Chemical evolution

Daniel Nichol, Mark Robertson-Tessi, Peter Jeavons, Alexander R A Anderson
Non-genetic variation in phenotypes, or bet-hedging, has been observed as a driver of drug resistance in both bacterial infections and cancers. Here, we study how bet-hedging emerges in the genotype-phenotype mapping through a simple interaction model: a molecular switch. We use simple Chemical Reaction Networks to implement stochastic switches that map gene products to phenotypes and investigate the impact of structurally distinct mappings on the evolution of phenotypic heterogeneity. Bet-hedging naturally emerges within this model and is robust to evolutionary loss through mutations to both the expression of individual genes and to the network itself...
October 21, 2016: Genetics
Fengjiao Chen, Qishan Zhu, Yeyun Wang, Wei Cui, Xiaodong Su, Yanguang Li
Increasing attention has now been focused on the photoelectrochemical (PEC) hydrogen evolution as a promising route to transform solar energy into chemical fuels. Silicon is one of the most studied PEC electrode materials, but its performance is still limited by its inherent PEC instability and electrochemical inertness toward water splitting. To achieve significant PEC activities, silicon-based photoelectrodes usually have to be coupled with proper cocatalysts, and thus formed semiconductor/cocatalyst interface represents a critical structural parameter in the rational design of efficient PEC devices...
October 21, 2016: ACS Applied Materials & Interfaces
Giorgio Lanzani, Ari P Seitsonen, Marcella Iannuzzi, Kari Laasonen, Simo Olavi Pehkonen
The chemistry of aluminium or oxo-aluminium in water is still relatively unknown, although it is the basis for many chemical and industrial processes, including floc- culation in water treatment plants. Trimeric species have a predominant role in the formation of the Keggin cations, which are the basic building block of aluminium- based chemicals. Despite this, the details of the structural evolution of these small solvated clusters and how this is related to the processes leading to the formation of larger aggregates is still an open issue...
October 21, 2016: Journal of Physical Chemistry. B
Lêniféré Chantal Soro, Sylvie Munier, Yves Pelissier, Lidwine Grosmaire, Rickey Yada, David Kitts, Anin Louise Ocho-Anin Atchibri, Caroline Guzman, Frédéric Boudard, Chantal Menut, Jean Charles Robinson, Patrick Poucheret
ETHNOPHARMACOLOGICAL RELEVANCE: Lippia multiflora is a plant with nutritional and pharmaco-therapeutic properties that is native to central and occidental Africa. The potential effects of plants on health are associated with their chemical composition. Therefore, the present study aimed to identify chemical variations in essential oils of Lippia multiflora as a function of geographic origin and time of annual harvest to determine optimal chemical profiles for ethno-pharmacotherapeutic applications...
October 17, 2016: Journal of Ethnopharmacology
Sampada Chitale, Joshua S Derasp, Bashir Hussain, Kashif Tanveer, André M Beauchemin
Directed hydration of α-amino nitriles was achieved under mild conditions using simple carbohydrates as catalysts exploiting temporary intramolecularity. A broadly applicable procedure using both formaldehyde and NaOH as catalysts efficiently hydrated a variety of primary and secondary susbtrates, and allowed the hydration of enantiopure substrates to proceed without racemization. This work also provides a rare comparison of the catalytic activity of carbohydrates, and shows that the simple aldehydes at the basis of chemical evolution are efficient organocatalysts mimicking the function of hydratase enzymes...
October 20, 2016: Chemical Communications: Chem Comm
Nashmiah Aid Alrashedy, Jeanmaire Molina
Psychoactive plants contain chemicals that presumably evolved as allelochemicals but target certain neuronal receptors when consumed by humans, altering perception, emotion and cognition. These plants have been used since ancient times as medicines and in the context of religious rituals for their various psychoactive effects (e.g., as hallucinogens, stimulants, sedatives). The ubiquity of psychoactive plants in various cultures motivates investigation of the commonalities among these plants, in which a phylogenetic framework may be insightful...
2016: PeerJ
Samuele Maramai, Sandra Gemma, Simone Brogi, Giuseppe Campiani, Stefania Butini, Holger Stark, Margherita Brindisi
D3 receptors represent a major focus of current drug design and development of therapeutics for dopamine-related pathological states. Their close homology with the D2 receptor subtype makes the development of D3 selective antagonists a challenging task. In this review, we explore the relevance and therapeutic utility of D3 antagonists or partial agonists endowed with multireceptor affinity profile in the field of central nervous system disorders such as schizophrenia and drug abuse. In fact, the peculiar distribution and low brain abundance of D3 receptors make them a valuable target for the development of drugs devoid of motor side effects classically elicited by D2 antagonists...
2016: Frontiers in Neuroscience
Yue Zhang, Richard Potter, William Zhang, Zahra Fakhraai
Recent studies have shown that diffusion on the surface of organic glasses can be many orders of magnitude faster than bulk diffusion. Developing new probes that can readily measure surface diffusion can help study the effect of parameters such as chemical structure, intermolecular interaction, molecules' shape and size on the enhanced surface diffusion. In this study, we develop a novel probe that significantly simplifies these types of studies. Tobacco mosaic virus (TMV) is used as probe particle to measure surface diffusion coefficient of molecular glass N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD)...
October 19, 2016: Soft Matter
Won-Hee Ryu, Forrest S Gittleson, Julianne M Thomsen, Jinyang Li, Mark J Schwab, Gary W Brudvig, André D Taylor
One of the greatest challenges with lithium-oxygen batteries involves identifying catalysts that facilitate the growth and evolution of cathode species on an oxygen electrode. Heterogeneous solid catalysts cannot adequately address the problematic overpotentials when the surfaces become passivated. However, there exists a class of biomolecules which have been designed by nature to guide complex solution-based oxygen chemistries. Here, we show that the heme molecule, a common porphyrin cofactor in blood, can function as a soluble redox catalyst and oxygen shuttle for efficient oxygen evolution in non-aqueous Li-O2 batteries...
October 19, 2016: Nature Communications
Dennis G Hall, Taras Rybak, Tristan Verdelet
Multicomponent reactions (MCR), transformations employing three or more simple substrates in a single and highly atom-economical operation, are very attractive in both natural product synthesis and diversity-oriented synthesis of druglike molecules. Several popular multicomponent reactions were designed by combining two well-established individual reactions that utilize mutually compatible substrates. In this regard, it is not surprising that the merging of two reactions deemed as workhorses of stereoselective synthesis, the Diels-Alder cycloaddition and carbonyl allylboration, would produce a powerful and highly versatile tandem MCR process...
October 18, 2016: Accounts of Chemical Research
Liang Hu, Yao Huang, Wenyu Chen, Xin Fu, Haibo Xie
The morphology and dynamics of the pendant drops attached to the chemically patterned surfaces (pattern-pinned pendant drop) with different hydrophilic/hydrophobic contrast are investigated experimentally and numerically. During the experiments, the evolution of the contact angle and the maximum drop volume is found to be different from the traditional pendant drops whose contact line pinned on the edge of the tips (tip-pinned pendant drop), and the deviation is related both to the pattern radius and the wettability contrast...
October 18, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Tingting Wu, James D Englehardt
An urban net-zero water treatment system, designed for energy-positive water management, 100% recycle of comingled black/grey water to drinking water standards, and mineralization of hormones and other organics, without production of concentrate, was constructed and operated for two years, serving an occupied four-bedroom, four-bath university residence hall apartment. The system comprised septic tank, denitrifying membrane bioreactor (MBR), iron-mediated aeration (IMA) reactor, vacuum ultrafilter, and peroxone or UV/H2O2 advanced oxidation, with 14% rainwater make-up and concomitant discharge of 14% of treated water (ultimately for reuse in irrigation)...
October 5, 2016: Water Research
Yang Yang, Di Xu, Qingyong Wu, Peng Diao
Solar powered hydrogen evolution reaction (HER) is one of the key reactions in solar-to-chemical energy conversion. It is desirable to develop photocathodic materials that exhibit high activity toward photoelectrochemical (PEC) HER at more positive potentials because a higher potential means a lower overpotential for HER. In this work, the Cu2O/CuO bilayered composites were prepared by a facile method that involved an electrodeposition and a subsequent thermal oxidation. The resulting Cu2O/CuO bilayered composites exhibited a surprisingly high activity and good stability toward PEC HER, expecially at high potentials in alkaline solution...
October 17, 2016: Scientific Reports
Carien Coetzee, Elizma Van Wyngaard, Katja Šuklje, Antonio C Silva Ferreira, Wessel J du Toit
The effect of repetitive controlled oxidation on the chemical and sensory composition of a fresh and fruity style Sauvignon blanc wine was investigated. Chemical analyses were conducted together with extensive sensory profiling. A decrease in volatile thiols responsible for the fruity nuances and an increase in oxidation-related compounds, such as acetaldehyde, during the course of the oxidation was observed. The wine evolved from a fresh and fruity one to one with slight oxidation and then developed extreme oxidative characteristics...
October 17, 2016: Journal of Agricultural and Food Chemistry
Ibrahim Saana Amiinu, Jian Zhang, Zongkui Kou, Xiaobo Liu, Owusu Kwadwo Asare, Huang Zhou, Kun Cheng, Haining Zhang, Liqiang Mai, Mu Pan, Shichun Mu
3D graphene-based materials offer immense potentials to overcome the challenges related to the functionality, performance, cost, and stability of fuel cell electrocatalysts. Herein, a nitrogen (N) and sulfur (S) dual-doped 3D porous graphene catalyst is synthesized via a single-row pyrolysis using biomass as solitary source for both N and S, and a structure directing agent. The thermochemical reaction of biomass functional groups with graphene oxide facilitates in situ generation of reactive N and S species, stimulating the graphene layers to reorganize into a trimodal 3D porous assembly...
October 14, 2016: ACS Applied Materials & Interfaces
Eugene Stephane Mananga, Bingwen Hu
The importance of the average Hamiltonian theory and its antecedent the Magnus expansion are discussed. The investigation of its convergence in different situations is very important. In this paper, we introduced a well-established approach to minimize the zeroth order average Hamiltonian for modified composite pulse sequence in quadrupolar spectroscopy of spin-1. We designed two modified composite pulse sequences constructed by modifying the timing sequence in the original composite pulse sequences17. We tested various configurations of times associated with the free evolution of spin system in the modified composite pulses...
October 14, 2016: Journal of Physical Chemistry. A
Roberto Matassa, Giuseppe Familiari, Ezio Battaglione, Concita Sibilia, Grigore Leahu, Alessandro Belardini, Iole Venditti, Laura Fontana, Ilaria Fratoddi
Today, nanochemistry research of hybrid materials growth in liquid media represents a new challenge for tailoring specific nano-sized materials directly related to the hybrid electron-optical properties. Distinctive assumptions about the origin, the growth, and the functionalization of hybrid nanoparticles have recently been proposed by scientific research to attend the different aspects of observable behaviors. Therefore, appropriate morpho-structural observation of the hybrid nanoparticles is the most important factor for controlling the chemical and physical properties...
October 14, 2016: Nanoscale
Fuminao Kishimoto, Masayuki Matsuhisa, Shinichiro Kawamura, Satoshi Fujii, Shuntaro Tsubaki, Masato M Maitani, Eiichi Suzuki, Yuji Wada
Various microwave effects on chemical reactions have been observed, reported and compared to those carried out under conventional heating. These effects are classified into thermal effects, which arise from the temperature rise caused by microwaves, and non-thermal effects, which are attributed to interactions between substances and the oscillating electromagnetic fields of microwaves. However, there have been no direct or intrinsic demonstrations of the non-thermal effects based on physical insights. Here we demonstrate the microwave enhancement of oxidation current of water to generate dioxygen with using an α-Fe2O3 electrode induced by pulsed microwave irradiation under constantly applied potential...
October 14, 2016: Scientific Reports
Marta Cavo, Marco Fato, Leonardo Peñuela, Francesco Beltrame, Roberto Raiteri, Silvia Scaglione
Three-dimensional (3D) cell cultures represent fundamental tools for the comprehension of cellular phenomena both in normal and in pathological conditions. In particular, mechanical and chemical stimuli play a relevant role on cell fate, cancer onset and malignant evolution. Here, we use mechanically-tuned alginate hydrogels to study the role of substrate elasticity on breast adenocarcinoma cell activity. The hydrogel elastic modulus (E) was measured via atomic force microscopy (AFM) and a remarkable range (150-4000 kPa) was obtained...
October 13, 2016: Scientific Reports
Monica Rodríguez-Bolaños, Nallely Cabrera, Ruy Perez-Montfort
The reactivation of triosephosphate isomerase (TIM) from unfolded monomers induced by guanidine hydrochloride involves different amino acids of its sequence in different stages of protein refolding. We describe a systematic mutagenesis method to find critical residues for certain physico-chemical properties of a protein. The two similar TIMs of Trypanosoma brucei and Trypanosoma cruzi have different reactivation velocities and efficiencies. We used a small number of chimeric enzymes, additive mutants and planned site-directed mutants to produce an enzyme from T...
October 2016: Open Biology
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