jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Hisham Abu-Ali | Alexei Nabok | Thomas J. Smith
Source: Analytical and Bioanalytical Chemistry (article, 2019-06-03)
Field: Chemistry — Electrochemistry

Electrochemical inhibition bacterial sensor array for detection of water pollutants: artificial neural network (ANN) approach This work reports on further development of an inhibition electrochemical sensor array based on immobilized bacteria for the preliminary detection of a wide range of organic and inorganic pollutants, such as heavy metal salts (HgCl<sub>2</sub>, PbCl<sub>2</sub>, CdCl<sub>2</sub>), pesticides (atrazine, simazine, DDVP), and petrochemicals (hexane, octane, pentane, toluene, pyrene, and ethanol) in water. A series of DC and AC electrochemical measurements, e.g., cyclic voltammograms and impedance spectroscopy, were carried out on screen-printed gold electrodes with three types of bacteria, namely Escherichia coli, Shewanella oneidensis, and Methylococcus capsulatus, immobilized via poly L-lysine. The results obtained showed a possibility of pattern recognition of the above pollutants by their inhibition effect on the three bacteria used. The analysis of a large amount of experimental data was carried out using an artificial neural network (ANN) programme for more accurate identification of pollutants as well as the estimation of their concentration. The results are encouraging for the development of a simple and cost-effective biosensing technology for preliminary in-field analysis (screening) of water samples for the presence of environmental pollutants. Graphical abstract. Chemistry ; Shewanella oneidensis ; Pollutant ; Biosensor ; Environmental chemistry ; Chromatography ; Bacteria ; Organic chemistry ; Biochemistry Electrochemical Analysis and Applications ; Analytical Chemistry and Sensors ; Biosensors and Analytical Detection
Authors: Gongyu Li | Fengfei Ma | Qinjingwen Cao | Zhen Zheng | Kellen DeLaney | Rui Liu | Lingjun Li
Source: Nature Communications (article, 2019-10-16)
Field: Chemistry — Organic Chemistry

Nanosecond photochemically promoted click chemistry for enhanced neuropeptide visualization and rapid protein labeling Comprehensive protein identification and concomitant structural probing of proteins are of great biological significance. However, this is challenging to accomplish simultaneously in one confined space. Here, we develop a nanosecond photochemical reaction (nsPCR)-based click chemistry, capable of structural probing of proteins and enhancing their identifications through on-demand removal of surrounding matrices within nanoseconds. The nsPCR is initiated using a photoactive compound, 2-nitrobenzaldehyde (NBA), and is examined by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). Benefiting from the on-demand matrix-removal effect, this nsPCR strategy enables enhanced neuropeptide identification and visualization from complex tissue samples such as mouse brain tissue. The design shows great promise for structural probing of proteins up to 155 kDa due to the exclusive accessibility of nsPCR to primary amine groups, as demonstrated by its general applicability using a series of proteins with various lysine residues from multiple sample sources, with accumulated labeling efficiencies greater than 90%. Click chemistry ; Nanosecond ; Visualization ; Neuropeptide ; Chemistry ; Biophysics ; Computer science ; Nanotechnology ; Biochemistry ; Combinatorial chemistry ; Materials science ; Biology ; Physics ; Artificial intelligence ; Optics Click Chemistry and Applications ; Advanced Proteomics Techniques and Applications ; Advanced biosensing and bioanalysis techniques
Authors: Dale E. Newbury | Nicholas W. M. Ritchie
Source: Microscopy and Microanalysis (article, 2019-08-23)
Field: Materials Science — Surfaces, Coatings and Films

Electron-Excited X-ray Microanalysis by Energy Dispersive Spectrometry at 50: Analytical Accuracy, Precision, Trace Sensitivity, and Quantitative Compositional Mapping 2018 marked the 50th anniversary of the introduction of energy dispersive X-ray spectrometry (EDS) with semiconductor detectors to electron-excited X-ray microanalysis. Initially useful for qualitative analysis, EDS has developed into a fully quantitative analytical tool that can match wavelength dispersive spectrometry for accuracy in the determination of major (mass concentration C > 0.1) and minor (0.01 ≤ C ≤ 0.1) constituents, and useful accuracy can extend well into the trace (0.001 < C < 0.01) constituent range even when severe peak interference occurs. Accurate analysis is possible for low atomic number elements (B, C, N, O, and F), and at low beam energy, which can optimize lateral and depth spatial resolution. By recording a full EDS spectrum at each picture element of a scan, comprehensive quantitative compositional mapping can also be performed. Microanalysis ; Analytical Chemistry (journal) ; Resolution (logic) ; Mass spectrometry ; Excited state ; Electron probe microanalysis ; X-ray ; Range (aeronautics) ; TRACE (psycholinguistics) ; Chemistry ; Materials science ; Optics ; Physics ; Atomic physics ; Scanning electron microscope ; Chromatography Electron and X-Ray Spectroscopy Techniques ; X-ray Spectroscopy and Fluorescence Analysis ; Ion-surface interactions and analysis
Authors: Yang Yuan | Suliang Ma | Jianwen Wu | Bowen Jia | Weixin Li | Luo Xiaowu
Source: Sensors (article, 2019-04-25)
Field: Materials Science — Materials Chemistry

Frequency Feature Learning from Vibration Information of GIS for Mechanical Fault Detection The reliability of gas insulated switchgear (GIS) is very important for the safe operation of power systems. However, the research on potential faults of GIS is mainly focused on partial discharge, and the research on the intelligent detection technology of the mechanical state of GIS is very scarce. Based on the abnormal vibration signals generated by a GIS fault, a fault diagnosis method consisting of a frequency feature extraction method based on coherent function (CF) and a multi-layer classifier was developed in this paper. First, the Fourier transform was used to analyze the differences and consistency in the frequency spectrum of signals. Secondly, the frequency domain commonalities of the vibration signals were extracted by using CF, and the vibration characteristics were screened twice by using the correlation threshold and frequency threshold to further select the vibration features for diagnosis. Then, a multi-layer classifier composed of two one-class support vector machines (OCSVMs) and one support vector machine (SVM) was designed to classify the faults of GIS. Finally, the feasibility of the feature extraction method was verified by experiments, and compared with other classification methods, the stability and reliability of the proposed classifier were verified, which indicates that the fault diagnosis method promotes the development of an intelligent detection technology of the mechanical state in GIS. Support vector machine ; Switchgear ; Feature extraction ; Vibration ; Classifier (UML) ; Pattern recognition (psychology) ; Fast Fourier transform ; Computer science ; Frequency domain ; Artificial intelligence ; Fault (geology) ; Data mining ; Engineering ; Computer vision ; Algorithm ; Acoustics High voltage insulation and dielectric phenomena ; Elevator Systems and Control ; Power Transformer Diagnostics and Insulation
Authors: Ohad Rozen | Vered Shwartz | Roee Aharoni | Ido Dagan
Source:  (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Diversify Your Datasets: Analyzing Generalization via Controlled Variance in Adversarial Datasets Phenomenon-specific "adversarial" datasets have been recently designed to perform targeted stress-tests for particular inference types. Recent work (Liu et al., 2019a) proposed that such datasets can be utilized for training NLI and other types of models, often allowing to learn the phenomenon in focus and improve on the challenge dataset, indicating a "blind spot" in the original training data. Yet, although a model can improve in such a training process, it might still be vulnerable to other challenge datasets targeting the same phenomenon but drawn from a different distribution, such as having a different syntactic complexity level. In this work, we extend this method to drive conclusions about a model's ability to learn and generalize a target phenomenon rather than to "learn" a dataset, by controlling additional aspects in the adversarial datasets. We demonstrate our approach on two inference phenomena -dative alternation and numerical reasoning, elaborating, and in some cases contradicting, the results of Liu et al.. Our methodology enables building better challenge datasets for creating more robust models, and may yield better model understanding and subsequent overarching improvements. Computer science ; Phenomenon ; Adversarial system ; Inference ; Machine learning ; Generalization ; Artificial intelligence ; Focus (optics) ; Variance (accounting) ; Process (computing) ; Mathematics Machine Learning in Materials Science ; Explainable Artificial Intelligence (XAI) ; Adversarial Robustness in Machine Learning
Authors: Devendra Mohan | Markandeya Tiwari | Suman Kr. Dey | Shyam Bihari Dwivedi | Sheo Prasad Shukla
Source: Current Science (article, 2019-08-25)
Field: Chemistry — Analytical Chemistry

Adsorption of Arsenic using Low Cost Adsorbents:Guava Leaf Biomass, Mango Bark and Bagasse Adsorbents prepared from inexpensive materials of guava leaf biomass, mango bark and bagasse were studied for As(III) removal from the aqueous solution. The effects of pH, contact time, initial As(III) concentration and adsorbent dosage on the adsorption of As(III) were studied using batch experiments. Adsorption process was also verified with Langmuir, Freundlich, Temkin and Redlich-Peterson models. Langmuir isotherm fitted best in the experimental data. Application of Langmuir isotherm to the system yielded the maximum capacities of 1.35 mg g -1 , 1.25 mg g -1 and 1.05 mg g -1 for bagasse, mango bark and guava leaf biomass respectively, in the range of As(III) concentration as 10-140 mg l -1 . The dimensionless equilibrium parameter, R L , signifies favourable adsorption of As(III) on all adsorbents and was observed to be in the range of 0.029-0.294, 0.021-0.235 and 0.021-0.234, for bagasse, mango bark and guava leaf biomass respectively (0 < R L < 1). The adsorption process was observed to follow pseudosecond-order kinetic model. Bagasse ; Adsorption ; Bark (sound) ; Biomass (ecology) ; Arsenic ; Pulp and paper industry ; Chemistry ; Environmental science ; Botany ; Waste management ; Agronomy ; Biology ; Organic chemistry ; Engineering Dye analysis and toxicity ; Potato Plant Research ; Plant and soil sciences
Authors: Xavier Boyat | Dorick Ballat-Durand | Julie Marteau | Salima Bouvier | Jérôme Favergeon | Andrey Orekhov | D. Schryvers
Source: Materials Characterization (article, 2019-10-16)
Field: Materials Science — Materials Chemistry

Interfacial characteristics and cohesion mechanisms of linear friction welded dissimilar titanium alloys: Ti–5Al–2Sn–2Zr–4Mo–4Cr (Ti17) and Ti–6Al–2Sn–4Zr–2Mo (Ti6242) Materials science ; Cohesion (chemistry) ; Titanium alloy ; Titanium ; Welding ; Metallurgy ; Friction welding ; Alloy Titanium Alloys Microstructure and Properties ; Advanced Welding Techniques Analysis ; Intermetallics and Advanced Alloy Properties
Authors: Zhonglei Wang
Source: Molecules (review, 2019-09-19)
Field: Chemistry — Organic Chemistry

Advances in the Asymmetric Total Synthesis of Natural Products Using Chiral Secondary Amine Catalyzed Reactions of α,β-Unsaturated Aldehydes Chirality is one of the most important attributes for its presence in a vast majority of bioactive natural products and pharmaceuticals. Asymmetric organocatalysis methods have emerged as a powerful methodology for the construction of highly enantioenriched structural skeletons of the target molecules. Due to their extensive application of organocatalysis in the total synthesis of bioactive molecules and some of them have been used in the industrial synthesis of drugs have attracted increasing interests from chemists. Among the chiral organocatalysts, chiral secondary amines (MacMillan's catalyst and Jorgensen's catalyst) have been especially considered attractive strategies because of their impressive efficiency. Herein, we outline advances in the asymmetric total synthesis of natural products and relevant drugs by using the strategy of chiral secondary amine catalyzed reactions of α,β-unsaturated aldehydes in the last eighteen years. Catalysis ; Amine gas treating ; Chemistry ; Organic chemistry ; Total synthesis ; Aldehyde ; Enantioselective synthesis ; Combinatorial chemistry Asymmetric Synthesis and Catalysis ; Synthetic Organic Chemistry Methods ; Chemical synthesis and alkaloids
Authors: Zunfu Hu | Zhichao Dai | Xiaowei Hu | Baochan Yang | Qingyun Liu | Chuanhui Gao | Xiuwen Zheng | Yueqin Yu
Source: Journal of Nanobiotechnology (article, 2019-03-13)
Field: Materials Science — Materials Chemistry

A facile preparation of FePt-loaded few-layer MoS2 nanosheets nanocomposites (F-MoS2-FePt NCs) and their application for colorimetric detection of H2O2 in living cells These findings indicated that the F-MoS<sub>2</sub>-FePt-TMB-H<sub>2</sub>O<sub>2</sub> system provides a potential sensing platform for hydrogen peroxide monitoring in living cells. Molybdenum disulfide ; Nanocomposite ; Detection limit ; Transmission electron microscopy ; Hydrogen peroxide ; Nanoparticle ; Catalysis ; Substrate (aquarium) ; Nanotechnology ; Colorimetry ; Materials science ; Monolayer ; Chemical engineering ; Layer (electronics) ; Chemistry ; Nuclear chemistry ; Chromatography ; Biochemistry ; Metallurgy Advanced Nanomaterials in Catalysis ; Advanced biosensing and bioanalysis techniques ; Electrochemical sensors and biosensors
Authors: Eleonora Venezia | Massimo Viviani | Sabrina Presto | R. Vasant Kumar | Rumen I. Tomov
Source: Nanomaterials (article, 2019-04-24)
Field: Materials Science — Materials Chemistry

Inkjet Printing Functionalization of SOFC LSCF Cathodes An important segment of the future renewable energy economy is the implementation of novel energy generation systems. Such electrochemical systems are solid oxide fuel cells, which have the advantage of direct conversion of the chemical energy stored in the fuel to electrical energy with high efficiency. Improving the performance and lowering the cost of solid oxide fuel cells (SOFCs) are strongly dependent on finding commercially viable methods for nano-functionalization of their electrodes via infiltration. Inkjet printing technology was proven to be a feasible method providing scalability and high-resolution ink delivery. LaxSr1−xCoyFe1−yO3−δ cathodes were modified using inkjet printing for infiltration with two different materials: Gd-doped ceria (CGO) commonly used as ion-conductor and La0.6Sr0.4CoO3–δ (LCO) commonly used as a mixed ionic electronic conductor. As-modified surface structures promoted the extension of the three-phase boundary (TPB) and enhanced the mechanisms of the oxygen reduction reaction. Electrochemical impedance measurements revealed significantly lowered polarization resistances (between 2.7 and 3.7 times) and maximum power output enhancement of 24% for CGO infiltrated electrodes and 40% for LCO infiltrated electrodes. Materials science ; Surface modification ; Cathode ; Oxide ; Solid oxide fuel cell ; Chemical engineering ; Anode ; Electrochemistry ; Nanotechnology ; Polarization (electrochemistry) ; Electrochemical energy conversion ; Electrode ; Electrical engineering ; Chemistry Advancements in Solid Oxide Fuel Cells ; Electronic and Structural Properties of Oxides ; Catalytic Processes in Materials Science
Authors: Guilherme S. Caleffi | Olatz Larrañaga | Marcos Ferrándiz-Saperas | Paulo R. R. Costa | Carmén Nájera | Abel de Cózar | Fernando P. Cossío | José M. Sansano
Source: The Journal of Organic Chemistry (article, 2019-07-26)
Field: Chemistry — Organic Chemistry

Switching Diastereoselectivity in Catalytic Enantioselective (3+2) Cycloadditions of Azomethine Ylides Promoted by Metal Salts and Privileged Segphos-Derived Ligands Catalytic enantioselective 1,3-dipolar cycloaddition between imino esters and electrophilic alkenes, employing chiral metal complexes derived from copper(I) and silver(I) salts and (<i>S</i>)-DM- or (<i>S</i>)-DTBM-Segphos as ligands produces diastereodivergently exo- or endo-cycloadducts, respectively. The effect of the functional group of the dipolarophile and the fine tuning of the catalyst plays an important role in promoting reverse diastereoselectivities. The origins of experimentally observed enantioselectivity and diastereoselectivity data, as well as the origin of the observed switched endo/exo ratios, are also explained by means of density functional theory calculations. Enantioselective synthesis ; Electrophile ; Cycloaddition ; Catalysis ; Chemistry ; Density functional theory ; Metal ; Copper ; Combinatorial chemistry ; Medicinal chemistry ; Computational chemistry ; Organic chemistry Synthesis and Catalytic Reactions ; Cyclopropane Reaction Mechanisms ; Asymmetric Synthesis and Catalysis
Authors: Fengmin Nie | Jing Cui | Yufeng Zhou | Li Pan | Zhe Ma | Yue‐Sheng Li
Source: Macromolecules (article, 2019-07-09)
Field: Materials Science — Polymers and Plastics

Molecular-Level Tuning toward Aggregation Dynamics of Self-Healing Materials Polymerized ionic liquids (PILs) represent one class of promising candidates for self-healing materials because of the potential diffusion of ion pairs from one aggregation to another. Therefore, dynamics of ionic aggregation plays the crucial role in the self-healing process. However, a win–win situation to both self-healing efficiency and mechanical strength is a major challenge for PILs and even all intrinsic healable materials. To resolve this challenge, a series of novel imidazolium-based norbornene PILs with fine-tuned side-chain microstructures were synthesized in the present work. The inserted imidazolium groups divide side chains into two parts: spacer and tail. By tuning the length of these two parts independently, self-healing efficiency of PILs could be significantly improved without sacrificing the mechanical strength. The increase in spacer segments by eight methylenes decreased the glass transition temperature by 70 °C and turned the PIL from a strong material into a highly stretchable material. It was very useful to find that tuning the lengths of spacer and tail conversely could achieve comparable mechanical strength. More importantly, our results revealed that long tail segments with 5, 7, or 9 methylenes formed an additional tail region between ionic aggregations, which remarkably reduced the average aggregation distance and consequently accelerates healing kinetics. The understanding on structure-healing interplay provides a convenient and efficient molecular design approach for optimizing mechanical strength and healing efficiency simultaneously. Self-healing ; Materials science ; Ionic liquid ; Self-healing material ; Mechanical strength ; Polymer ; Molecular dynamics ; Side chain ; Ionic strength ; Polymerization ; Microstructure ; Glass transition ; Norbornene ; Elongation ; Composite material ; Chemical physics ; Chemistry ; Organic chemistry ; Computational chemistry ; Ultimate tensile strength ; Aqueous solution Polymer composites and self-healing ; Carbon dioxide utilization in catalysis ; Advanced Sensor and Energy Harvesting Materials
Authors: Zonglin Gu | Wei Song | Serena H. Chen | Baoyu Li | Weifeng Li | Ruhong Zhou
Source: Nanoscale (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Defect-assisted protein HP35 denaturation on graphene Structural defects in nanomaterials can alter their physical and chemical properties including magnetization, electronic and thermal conductivities, light absorption, and emission capabilities. Here, we investigated the potential impact of these defects on their biological effects through molecular dynamics simulations. By modeling the interaction between a graphene nanosheet and a widely used model protein, the chicken villin headpiece subdomain (HP35), we observed severe protein denaturation upon contact with defective graphene, while the protein remained intact on ideal graphene. The enhanced toxicity of defective graphene was due to the stronger attraction of the surface residues of HP35 from the defect edges (represented by carboxyl groups in our simulations) than from the ideal graphene. Upon binding to defective graphene, the contacting residues were restrained near the defective sites, which acted as "anchors" for the adsorbed protein. The "anchors" subsequently caused the protein to expose its aromatic and hydrophobic core residues to the graphene surface, via strong π-π stacking and hydrophobic interactions, thus leading to the unfolding of the protein. These findings not only highlight the importance of defects in nanomaterials' impact on biological systems, but also provide insights into fine-tuning the potential biological properties of nanomaterials through defect engineering. Graphene ; Denaturation (fissile materials) ; Materials science ; Nanotechnology ; Biophysics ; Chemistry ; Biology ; Nuclear chemistry Graphene research and applications ; Graphene and Nanomaterials Applications ; Nanopore and Nanochannel Transport Studies
Authors: Wan Li | Michal Wojcik | Ke Xu
Source: Nano Letters (article, 2019-01-22)
Field: Materials Science — Materials Chemistry

Optical Microscopy Unveils Rapid, Reversible Electrochemical Oxidation and Reduction of Graphene We unveil the reaction dynamics of monolayer graphene in electrochemical oxidation and reduction processes through interference reflection optical microscopy. At 300 nm spatial resolution and 200 ms temporal resolution, we reveal rapid electrochemical oxidation of graphene, as well as its efficient electrochemical reduction back to the unoxidized state. We identify 1.4 V (vs Ag/AgCl) as the onset voltage for oxidation and show that the process is driven by free radicals generated in the electrolysis of water and so fully suppressible by a radical-trapping molecule. Moreover, we find the oxidation process to be spatially heterogeneous at the nanoscale, defect- and history-dependent, and characterized by a self-limiting effect unique to the two-dimensional system. We further demonstrate that electrochemical reduction rapidly reverses the oxidized graphene back to the unoxidized state in a controlled manner and find strong dependency of reduction speed on the reduction voltage and pH, from which we conclude a one-to-one relationship between protons and electrons in the reduction process. Besides elucidating the electrochemical reaction mechanisms of graphene, our results point to new pathways to the controlled generation and fine-tuning of graphene derivatives through electrochemistry. Graphene ; Electrochemistry ; Materials science ; Redox ; Electrolysis ; Nanotechnology ; Photochemistry ; Chemistry ; Electrode ; Chemical engineering ; Inorganic chemistry ; Physical chemistry ; Electrolyte Graphene research and applications ; Electrochemical Analysis and Applications ; Molecular Junctions and Nanostructures