jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Kamyar Mehrabi | Rälf Kaegi | Detlef Günther | Alexander Gundlach‐Graham
Source: Environmental Science Nano (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Emerging investigator series: automated single-nanoparticle quantification and classification: a holistic study of particles into and out of wastewater treatment plants in Switzerland Single particle inductively coupled plasma time-of-flight mass spectrometry (sp-ICP-TOFMS), in combination with online microdroplet calibration, allows for the determination of particle number concentrations (PNCs) and the amount (<i>i.e.</i> mass) of ICP-MS-accessible elements in individual particles. Because sp-ICP-TOFMS analyses of environmental samples produce rich datasets composed of both single-metal nanoparticles (smNPs) and many types of multi-metal NPs (mmNPs), interpretation of these data is well suited to automated analysis schemes. Here, we present a new data analysis approach that includes: 1. automatic particle detection and elemental mass determinations based on online microdroplet calibration, 2. correction of false (randomly occurring) multi-metal associations caused by measurement of coincident but distinct NPs, and 3. unsupervised clustering analysis of mmNPs to identify unique classes of NPs based on their element compositions. To demonstrate the potential of our approach, we analyzed water samples collected from the influent and effluent of five wastewater treatment plants (WWTPs) across Switzerland. We determined elemental masses in individual NPs, as well as PNCs, to estimate the NP removal efficiencies of the individual WWTPs. From WWTP samples collected at two points in time, we found an average of 90% and 94% removal efficiencies of single-metal and multi-metal NPs, respectively. Between 5% to 27% of detected NPs were multi-metal; the most abundant particle types were those rich in Ce-La, Fe-Al, Ti-Zr, and Zn-Cu. Through hierarchical clustering, we identified NP classes conserved across all WWTPs, as well as particle types that are unique to one or a few WWTPs. These uniquely occurring particle types may represent point sources of anthropogenic NPs. We describe the utility of clustering analysis of mmNPs for identifying natural, geogenic NPs, and also for the discovery of new, potentially anthropogenic, NP targets. Wastewater ; Nanoparticle ; Particle (ecology) ; Sewage treatment ; Throughput ; Series (stratigraphy) ; Environmental science ; Computer science ; Nanotechnology ; Biochemical engineering ; Materials science ; Engineering ; Environmental engineering ; Biology ; Ecology ; Telecommunications Nanoparticles: synthesis and applications ; Heavy metals in environment ; Healthcare and Environmental Waste Management
Authors: Engui Zhao | Sijie Chen
Source: Materials Chemistry Frontiers (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Materials with aggregation-induced emission characteristics for applications in diagnosis, theragnosis, disease mechanism study and personalized medicine In this review, we introduce the recent progress on the employment of AIE-active materials for healthcare-related applications, such as clinical diagnosis, theragnosis, disease mechanism studies and personalized medicines. Mechanism (biology) ; Personalized medicine ; Aggregation-induced emission ; Disease ; Disease treatment ; Nanotechnology ; Medicine ; Materials science ; Computer science ; Intensive care medicine ; Bioinformatics ; Physics ; Internal medicine ; Biology Luminescence and Fluorescent Materials ; Nanoplatforms for cancer theranostics ; Molecular Sensors and Ion Detection
Authors: Mario Gabrielli
Source: MDPI (MDPI AG) (article, 2021-04-01)
Field: Chemistry — Analytical Chemistry

Hyperspectral Imaging to Characterize Table Grapes Table grape quality is of importance for consumers and thus for producers. Its objective quality is usually determined by destructive methods mainly based on sugar content. This study proposed to evaluate the possibility of hyperspectral imaging to characterize table grapes quality through its sugar (TSS), total flavonoid (TF), and total anthocyanin (TA) contents. Different data pre-treatments (WD, SNV, and 1st and 2nd derivative) and different methods were tested to get the best prediction models: PLS with full spectra and then Multiple Linear Regression (MLR) were realized after selecting the optimal wavelengths thanks to the regression coefficients (β-coefficients) and the Variable Importance in Projection (VIP) scores. All models were good at showing that hyperspectral imaging is a relevant method to predict sugar, total flavonoid, and total anthocyanin contents. The best predictions were obtained from optimal wavelength selection based on β-coefficients for TSS and from VIPs optimal wavelength windows using SNV pre-treatment for total flavonoid and total anthocyanin content. Thus, good prediction models were proposed in order to characterize grapes while reducing the data sets and limit the data storage to enable an industrial use. Hyperspectral imaging ; Flavonoid ; Anthocyanin ; Partial least squares regression ; Mathematics ; Linear regression ; Sugar ; Table (database) ; Regression ; Computer science ; Pattern recognition (psychology) ; Artificial intelligence ; Statistics ; Food science ; Chemistry ; Data mining Spectroscopy and Chemometric Analyses ; Phytochemicals and Antioxidant Activities ; Horticultural and Viticultural Research
Authors: Martin D. Gelenter | Venkata S. Mandala | Michiel J.M. Niesen | Dina A. Sharon | Aurelio J. Dregni | Adam P. Willard | Mei Hong
Source: Communications Biology (article, 2021-03-12)
Field: Chemistry — Spectroscopy

Water orientation and dynamics in the closed and open influenza B virus M2 proton channels The influenza B M2 protein forms a water-filled tetrameric channel to conduct protons across the lipid membrane. To understand how channel water mediates proton transport, we have investigated the water orientation and dynamics using solid-state NMR spectroscopy and molecular dynamics (MD) simulations. <sup>13</sup>C-detected water <sup>1</sup>H NMR relaxation times indicate that water has faster rotational motion in the low-pH open channel than in the high-pH closed channel. Despite this faster dynamics, the open-channel water shows higher orientational order, as manifested by larger motionally-averaged <sup>1</sup>H chemical shift anisotropies. MD simulations indicate that this order is induced by the cationic proton-selective histidine at low pH. Furthermore, the water network has fewer hydrogen-bonding bottlenecks in the open state than in the closed state. Thus, faster dynamics and higher orientational order of water molecules in the open channel establish the water network structure that is necessary for proton hopping. Chemical physics ; Molecular dynamics ; Proton ; Proton transport ; Chemistry ; Dynamics (music) ; Water transport ; Relaxation (psychology) ; Hydrogen bond ; Water channel ; Protein dynamics ; Nuclear magnetic resonance spectroscopy ; Molecule ; Crystallography ; Membrane ; Computational chemistry ; Stereochemistry ; Water flow ; Physics ; Organic chemistry Advanced NMR Techniques and Applications ; Protein Structure and Dynamics ; Electron Spin Resonance Studies
Authors: Jie Jin | Ru-Qiu Zheng | Yin‐Ning Zhou | Zheng‐Hong Luo
Source: Macromolecules (article, 2021-08-26)
Field: Chemistry — Organic Chemistry

Network Formation Kinetics of Poly(dimethylsiloxane) Based on Step-Growth Polymerization Kinetic study of the step-growth polymerization of hydroxyl-terminated poly(dimethylsiloxane) (PDMS) and triisocyanate has been done in this work. Kinetic Monte Carlo simulations are performed to understand the experimental investigation of the cross-linked network formation. This approach enables us to afford a visualization of the entire network formation in detail and evaluate its characteristic properties. A comparison between the current simulation results and that from classical theories (e.g., Flory and Macosko–Miller theoretical calculations) is done. In addition, the Cole–Poehlein diffusion model based on the free volume theory, involving a parallel summation of the chemical and diffusional rate coefficients, is used to describe the effect of diffusion-controlled mechanism on polymerization. Moreover, the effect of experimental conditions, such as the ratio of [NCO]/[OH] and the molar mass of PDMS, on network formation kinetics is also investigated. The simulation results demonstrate that the [NCO]/[OH] ratios within the range of 1–1.2 and PDMS with lower molar mass are preferred to prepare a polymer network with a high cross-linking density. It is believed that the current kinetic modeling provides a way for better understanding the kinetics and optimizing the experimental conditions. Molar mass ; Kinetics ; Polymerization ; Polymer chemistry ; Diffusion ; Thermodynamics ; Kinetic energy ; Polymer ; Step-growth polymerization ; Work (physics) ; Materials science ; Chemistry ; Monte Carlo method ; Physical chemistry ; Organic chemistry ; Physics Advanced Polymer Synthesis and Characterization ; Polymer composites and self-healing ; biodegradable polymer synthesis and properties
Authors: Yongli Yang | Fred S. Cannon
Source: Journal of environmental chemical engineering (article, 2021-09-20)
Field: Materials Science — Polymers and Plastics

Preparation of activated carbon from pine sawdust with hydrothermal-pressure preconditioning Activated carbon ; Adsorption ; Sawdust ; Chemistry ; Pyrolysis ; Sorption ; Hydrothermal circulation ; Hydrothermal carbonization ; Langmuir adsorption model ; Nuclear chemistry ; Methylene blue ; Langmuir ; Chemical engineering ; BET theory ; Organic chemistry ; Catalysis ; Carbonization Polymer Foaming and Composites ; Phase Equilibria and Thermodynamics ; Thermochemical Biomass Conversion Processes
Authors: N. K. Soliman | A. F. Moustafa | H. R. Abd El-Mageed | Omima F. Abdel-Gawad | Esraa T. Elkady | Sayed A. Ahmed | Hussein S. Mohamed
Source: Scientific Reports (article, 2021-05-11)
Field: Chemistry — Organic Chemistry

Experimentally and theoretically approaches for disperse red 60 dye adsorption on novel quaternary nanocomposites Abstract A comprehensive study that combined both experimental and computational experiments was performed to evaluate the usage of organo-metal oxide nanocomposite for the elimination of disperse red 60 dye (DR) from aqueous solutions. Chitosan was modified by Schiff base to form nanoneedles chitosan-4-chloroacetophenone derivative. The derivatives were then impregnated with CeO 2 –CuO–Fe 2 O 3 or CeO 2 –CuO–Al 2 O 3 metal oxides to prepare a novel quarternary organo-metal oxide nanocomposite. The novel nanocomposite, chitosan-4-chloroacetophenone/CeO 2 –CuO–Fe 2 O 3 (CF) and chitosan-4-chloroacetophenone/CeO 2 –CuO–Al 2 O 3 (CA) are cheap and effective nano adsorbents that can be used for the uptake of DR from aqueous solution. The CF and CA nano-composites were characterized using different techniques. Moreover, the effect of adsorption parameters (initial DR concentration, time of contact, pH, temperature, and adsorbent mass) as well as CA and CF reusability tests were performed. Langmuir adsorption isotherm and pseudo-second-order kinetics models were best fitted with the adsorption process. The maximum amount of DR adsorbed was 100 mg/g on CF and CA at pH 2 and 4, respectively with a physical spontaneous, and exothermic adsorption process. Monte Carlo ( MC) simulation studies indicated the adsorption of DR molecule on the CF and CA surfaces following a parallel mode in most of all studied configurations, confirming the strong interactions between the DR and surfaces atoms of CF and CA. The molecular structure analysis of DR dye adsorbed on the surface of CF and CA indicated that the adsorption process related to Van der Waals dispersion force. Consequently, this helps to trap DR dye molecules on the surface of CF and CA (i.e., physical adsorption), which supports our experimental results. Adsorption ; Aqueous solution ; Nanocomposite ; Langmuir adsorption model ; Chitosan ; Oxide ; Materials science ; Chemical engineering ; Metal ; Molecule ; Exothermic reaction ; Kinetics ; Nuclear chemistry ; Chemistry ; Inorganic chemistry ; Nanotechnology ; Physical chemistry ; Organic chemistry Nanomaterials for catalytic reactions ; Adsorption and biosorption for pollutant removal ; Gold and Silver Nanoparticles Synthesis and Applications
Authors: Xiaoning Wang | Yumeng Zhao | Jialuo Li | Jiandong Pang | Qiang Wang | Bao Li | Hong‐Cai Zhou
Source: Dalton Transactions (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Biomimetic catalysts of iron-based metal–organic frameworks with high peroxidase-mimicking activity for colorimetric biosensing The field of metal-organic framework (MOF)-based biomimetic catalysts has achieved great progress but is still in its infancy. The systematic investigation of the tailored construction of MOF-based biomimetic catalysts is required for further development. Herein, two iron-based MOFs, namely, [(Fe<sub>3</sub>O)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>(HCOO)(L)<sub>2</sub>]<sub>n</sub> (HUST-5: H<sub>6</sub>L = hexakis(4-formylphenoxy) cyclotriphosphazene; HUST = Huazhong University of Science and Technology) and [(Fe<sub>3</sub>O)(H<sub>2</sub>O)<sub>3</sub>(L)]<sub>n</sub> (HUST-7) have been fabricated through the assembly of different iron clusters and hexa-carboxylate ligand under the control of the added acid species. The two MOFs exhibit distinct secondary building units (SBUs) and topological structures, which could be used as biomimetic catalysts for the systematic comparisons of structural characteristics and the catalytic activity. Both MOFs possess catalytic activity similar to that of natural peroxidases towards the catalysis of the oxidation of a variety of substrates. Significantly, HUST-5 and HUST-7 can effectively catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H<sub>2</sub>O<sub>2</sub> accompanied by significant colorimetric biosensing. With same compositions, different catalytic performances were obtained due to differences in the porous structures and characteristics of SBUs in two Fe-MOFs, which was also validated by theoretical calculation results. Furthermore, the phenomenon of colorimetric biosensing could be significantly suppressed by the addition of ascorbic acid (AA) during the oxidation process of TMB. It was observed from these findings that a facile colorimetric biosensing platform for detecting H<sub>2</sub>O<sub>2</sub> and ascorbic acid has been successfully explored. Therefore, this work provides another unique perspective for the tailor-made preparation of stable MOF-based peroxidase mimics with excellent catalytic performance and colorimetric biosensing. SBus ; Catalysis ; Biosensor ; Metal-organic framework ; Nanotechnology ; Peroxidase ; Materials science ; Combinatorial chemistry ; Chemistry ; Organic chemistry ; Enzyme Advanced Nanomaterials in Catalysis ; Advanced biosensing and bioanalysis techniques ; Nanocluster Synthesis and Applications
Authors: Ji Hong Gu | Wei Wang | Rong Yin | Chinh V Truong | Bibhu Prasad Ganthia
Source: Nonlinear Engineering (article, 2021-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Complex circuit simulation and nonlinear characteristics analysis of GaN power switching device Abstract To overcome the problem of energy losses in the electrical circuits and to improve the energy conversion efficiency, it is necessary to increase the power switch frequency and reduce the open resistance of the power switch. Moreover, based on energy saving, failure protection, circuit design and other aspects of the research of enhanced devices are also essential, a new static and dynamic model of GaN power transistor is proposed, and the steady-state and dynamic characteristics of GaN power transistors are simulated and tested. The GaN power transistor used in the test has a constant voltage of 450 V and a current of 4 A. By changing the driving power U, G (take 2, 3, 4V) and the stray inductance L s (take 2 μH, 5 μH), the switching characteristics of the simulation model were studied, and the simulation was carried out by changing the absorption capacitance C c (select 1.5 μF and 3.0 μF). This proposed simulation model can be used to analyze the protection effect of the buffer circuit under various stray inductors and help to guide the design of the buffer circuit. The simulation results of the static and dynamic models of the new GaN power transistor agree well with the experimental results. With the increase of U g , the opening speed is faster, but the turn-off delay is longer. With the increase of L s , the peak of the turn-off voltage increases. After increasing the absorption capacitance, the peak voltage during the turnoff is limited to the rated voltage, and the buffer circuit plays a protective role and the greater the C c , the better the protection. The simulation results are consistent with the theoretical analysis, which verifies the effectiveness of the model. Transistor ; Capacitance ; Inductance ; Power (physics) ; Power semiconductor device ; Spice ; Voltage ; Equivalent circuit ; Inductor ; Parasitic capacitance ; Electronic circuit ; Materials science ; Electrical engineering ; Electronic engineering ; Engineering ; Physics ; Electrode Electromagnetic wave absorption materials ; Applied Advanced Technologies ; GaN-based semiconductor devices and materials
Authors: Andreas Kunzendorf | Guangcai Xu | Mohammad Saifuddin | Thangavelu Saravanan | Gerrit J. Poelarends
Source: Angewandte Chemie International Edition (article, 2021-09-07)
Field: Chemistry — Organic Chemistry

Biocatalytic Asymmetric Cyclopropanations via Enzyme‐Bound Iminium Ion Intermediates Cyclopropane rings are an important structural motif frequently found in many natural products and pharmaceuticals. Commonly, biocatalytic methodologies for the asymmetric synthesis of cyclopropanes rely on repurposed or artificial heme enzymes. Here, we engineered an unusual cofactor-independent cyclopropanation enzyme based on a promiscuous tautomerase for the enantioselective synthesis of various cyclopropanes via the nucleophilic addition of diethyl 2-chloromalonate to α,β-unsaturated aldehydes. The engineered enzyme promotes formation of the two new carbon-carbon bonds with excellent stereocontrol over both stereocenters, affording the desired cyclopropanes with high diastereo- and enantiopurity (d.r. up to 25:1; e.r. up to 99:1). Our results highlight the usefulness of promiscuous enzymes for expanding the biocatalytic repertoire for non-natural reactions. Cyclopropanation ; Enantioselective synthesis ; Stereocenter ; Chemistry ; Cyclopropane ; Iminium ; Biocatalysis ; Stereochemistry ; Enzyme ; Nucleophile ; Cofactor ; Structural motif ; Combinatorial chemistry ; Organic chemistry ; Catalysis ; Ring (chemistry) ; Biochemistry ; Reaction mechanism Cyclopropane Reaction Mechanisms
Authors: Lauren Stopfer | Jason E. Conage‐Pough | Forest M. White
Source: Molecular & Cellular Proteomics (article, 2021-01-01)
Field: Chemistry — Spectroscopy

Quantitative Consequences of Protein Carriers in Immunopeptidomics and Tyrosine Phosphorylation MS2 Analyses Utilizing a protein carrier in combination with isobaric labeling to "boost" the signal of other low-level samples in multiplexed analyses has emerged as an attractive strategy to enhance data quantity while minimizing protein input in mass spectrometry analyses. Recent applications of this approach include pMHC profiling and tyrosine phosphoproteomics, two applications that are often limited by large sample requirements. While including a protein carrier has been shown to increase the number of identifiable peptides in both applications, the impact of a protein carrier on quantitative accuracy remains to be thoroughly explored, particularly in relevant biological contexts where samples exhibit dynamic changes in abundance across peptides. Here, we describe two sets of analyses comparing MS<sup>2</sup>-based quantitation using a 20× protein carrier in pMHC analyses and a high (~100×) and low (~9×) protein carrier in pTyr analyses, using CDK4/6 inhibitors and EGF stimulation to drive dynamic changes in the immunopeptidome and phosphoproteome, respectively. In both applications, inclusion of a protein carrier resulted in an increased number of MHC peptide or phosphopeptide identifications, as expected. At the same time, quantitative accuracy was adversely affected by the presence of the protein carrier, altering interpretation of the underlying biological response to perturbation. Moreover, for tyrosine phosphoproteomics, the presence of high levels of protein carrier led to a large number of missing values for endogenous phosphopeptides, leading to fewer quantifiable peptides relative to the "no-boost" condition. These data highlight the unique limitations and future experimental considerations for both analysis types and provide a framework for assessing quantitative accuracy in protein carrier experiments moving forward. Phosphoproteomics ; Phosphopeptide ; Isobaric labeling ; Quantitative proteomics ; Chemistry ; Proteomics ; Computational biology ; Peptide ; Protein phosphorylation ; Phosphorylation ; Biology ; Biochemistry ; Protein kinase A Advanced Proteomics Techniques and Applications ; Advanced biosensing and bioanalysis techniques ; Advanced Biosensing Techniques and Applications
Authors: Chunfeng Cui | Tao Ouyang | Chao Tang | Chaoyu He | Jin Li | Chunxiao Zhang | Jianxin Zhong
Source: Carbon (article, 2021-01-25)
Field: Materials Science — Materials Chemistry

Bayesian optimization-based design of defect gamma-graphyne nanoribbons with high thermoelectric conversion efficiency Thermoelectric effect ; Bayesian optimization ; Materials science ; Graphyne ; Figure of merit ; Seebeck coefficient ; Work (physics) ; Thermal conductivity ; Energy conversion efficiency ; Thermoelectric generator ; Non-equilibrium thermodynamics ; Mathematical optimization ; Thermodynamics ; Nanotechnology ; Optoelectronics ; Mathematics ; Physics ; Composite material Advanced Thermoelectric Materials and Devices ; Thermal properties of materials ; Graphene research and applications