jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Yanghune Ha | Riccardo Spezia | Kihyung Song
Source: ChemRxiv (preprint, 2020-06-24)
Field: Chemistry — Spectroscopy

Computer Simulation of Collision Induced Dissociation and Isolobal Analogy: The Case of Biotin and Its Analogues We have studied how collision induced dissociation (CID) products and associated mechanism are modified when a chemical group is modified by isolobal groups, and in particular S, O, NH and CH2. At this end, we have considered protonated biotin (vitamin B7) and corresponding oxybiotin, N-biotin and C-biotin, which have the same structures except for one chemical group (the S in biotin which is substituted with the aforementioned isolobal ones). Collisional simulations with Ar were performed to model CID fragmentations and to have directly access to related mechanisms. Simulations have shown that the CID fragmentation of the four compounds were similar and the resulting fragments involve in a similar way the isolobal groups. Details on the mechanisms as obtained from simulations are reported and discussed. This result shows that it is possible in principle to predict, with a reasonable confidence, mass spectra of unknown molecules based on mass spectrum of the known one when isolobal modifications are done. Fragmentation (computing) ; Dissociation (chemistry) ; Biotin ; Chemistry ; Collision-induced dissociation ; Protonation ; Collision ; Molecule ; Computational chemistry ; Computer science ; Mass spectrometry ; Combinatorial chemistry ; Tandem mass spectrometry ; Ion ; Physical chemistry ; Organic chemistry ; Biochemistry ; Chromatography Mass Spectrometry Techniques and Applications ; Molecular Junctions and Nanostructures ; Analytical Chemistry and Chromatography
Authors: Irene M. Gamba | Qin Li | Anjali Nair
Source: arXiv (Cornell University) (preprint, 2020-11-25)
Field: Materials Science — Materials Chemistry

Reconstructing the thermal phonon transmission coefficient at solid interfaces in the phonon transport equation The ab initio model for heat propagation is the phonon transport equation, a Boltzmann-like kinetic equation. When two materials are put side by side, the heat that propagates from one material to the other experiences thermal boundary resistance. Mathematically, it is represented by the reflection coefficient of the phonon transport equation on the interface of the two materials. This coefficient takes different values at different phonon frequencies, between different materials. In experiments scientists measure the surface temperature of one material to infer the reflection coefficient as a function of phonon frequency. In this article, we formulate this inverse problem in an optimization framework and apply the stochastic gradient descent (SGD) method for finding the optimal solution. We furthermore prove the maximum principle and show the Lipschitz continuity of the Fréchet derivative. These properties allow us to justify the application of SGD in this setup. Phonon ; Boltzmann equation ; Transmission coefficient ; Lipschitz continuity ; Reflection (computer programming) ; Reflection coefficient ; Thermal conductivity ; Measure (data warehouse) ; Inverse problem ; Mathematical analysis ; Condensed matter physics ; Physics ; Materials science ; Transmission (telecommunications) ; Mathematics ; Thermodynamics ; Computer science ; Optics Thermal properties of materials ; Thermography and Photoacoustic Techniques ; Numerical methods in inverse problems
Authors: K. V. Turov | Oleg P. Mitiukhin | С. А. Чумаченко | V. S. Zyabrev | В. С. Броварец
Source: Ukrainica Bioorganica Acta (article, 2020-06-30)
Field: Chemistry — Organic Chemistry

Anticancer evaluation of di- and trifunctional substituted 1,3-thiazoles Anticancer activity of a series of polyfunctional substituted 1,3-thiazoles has been studied within the international scientific program “NCI-60 Human Tumor Cell Lines Screen”. Screening was performed in vitro on 60 cell lines of lungs, kidneys, CNS, ovaries, prostate, and breast cancer, epithelial cancer, leukemia, and melanoma. The most effective compounds were those with a piperazine substituent at C2 of the 1,3-thiazole cycle: 1-(4-((4-methylphenyl)-sulfonyl)-2-phenyl-1,3-thiazol-5-yl)piperazine (average lg GI50 = -5.87, lg TGI = -5.54, lg LC50 = -5.21), 1-(2-(3,5-dimethyl-1H-pyrazol-1-yl)-4-((4-methylpheyl)sulfonyl)-1,3-thiazol-5-yl)piperazine (average lg GI50 = -5.66, lg TGI = -5.26, lg LC50 = -4.83), and 1-(2,4-bis((4-methylphenyl)sulfonyl)-1,3-thiazol-5-yl)piperazine (average lg GI50 = -5.67, lg TGI = -5.21, lg LC5050 = -4.67). Piperazine ; Sulfonyl ; Thiazole ; Chemistry ; Medicine ; Stereochemistry ; Organic chemistry Synthesis and biological activity ; Synthesis and Characterization of Heterocyclic Compounds ; Computational Drug Discovery Methods
Authors: Shengchao Gong | Mengxin Ren | Wei Wu | Wei Cai | Jingjun Xu
Source: arXiv (Cornell University) (preprint, 2020-03-11)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Optically Addressed Spatial Light Modulator based on Nonlinear Metasurface Spatial light modulators (SLMs) are devices for modulating amplitude, phase or polarization of a light beam on demand. Such devices have been playing an indispensable inuence in many areas from our daily entertainments to scientific researches. In the past decades, the SLMs have been mainly operated in electrical addressing (EASLM) manner, wherein the writing images are created and loaded via conventional electronic interfaces. However, adoption of pixelated electrodes puts limits on both resolution and efficiency of the EASLMs. Here, we present an optically addressed SLM based on a nonlinear metasurface (MS-OASLM), by which signal light is directly modulated by another writing beam requiring no electrode. The MS-OASLM shows unprecedented compactness and is 400 nm in total thickness benefitting from the outstanding nonlinearity of the metasurface. And their subwavelength feature size enables a high resolution up to 250 line pairs per millimeter, which is more than one order of magnitude better than any currently commercial SLMs. Such MS-OASLMs could provide opportunities to develop the next generation of high resolution displays and all-optical information processing technologies. Millimeter ; Optics ; Spatial light modulator ; Polarization (electrochemistry) ; Optoelectronics ; Materials science ; Signal beam ; Nonlinear system ; SIGNAL (programming language) ; Computer science ; Beam (structure) ; Physics Metamaterials and Metasurfaces Applications ; Photonic Crystals and Applications ; Photonic and Optical Devices
Authors: Nabia Ijaz | Sania Saeed | Sidra Khalid | Syeda Mahnoor Sajjad | Umme-Qadar | Iqra Zubair Awan | Syeda Zahra Aftab
Source: Zenodo (CERN European Organization for Nuclear Research) (article, 2020-08-26)
Field: Chemistry — Analytical Chemistry

Red Color Foods in Heart Health <strong>Red color foods and their impact on human health are always positive and beneficial. Lycopene is a carotenoid fight against cancer and cardiovascular diseases (CVD) while citrulline lowers the hypertension. Strawberries have a photochemical fight against hyperglycemia and dyslipidemia. The outcomes of sweet fruits as wellbeing promoters, especially their antimicrobial, cell reinforcement, anti diabetic, anticancer, hostile to neuro-degeneration, mitigating and cardiovascular effects is described in this study. Cherries as an antioxidant have blood cancer prevention agent capacity. Cherry-advanced weight control plans additionally diminished “greasy liver” or triglyceride and cholesterol gathering inside the liver. This organic product shows antibacterial, mitigating, antiviral, and against cancer-causing activities. Pomegranate counteracts diabetes, dental conditions, male erection, brokenness, bacterial contaminations, anti-infection obstruction, and skin harm brought about by bright. Aftereffects of a creature study demonstrated that both lycopene and tomato powder supplementation given independently were similarly successful and advantageous in lessening provocative and metabolic issues that happen with a high-fat eating routine. Strawberries are a rich wellspring of anthocyanin. An investigation on humans show drink of strawberry diminished feast evoked postprandial irritation as estimated by high-affectability C-receptive protein (hs-CRP) and IL-6, notwithstanding lessening postprandial insulin reaction. Solidified strawberries refreshment seems to have a calming reaction. Beet root contains contingents, a rich compound in decreasing irritation, oxidative pressure and dyslipidemia. Various constituents in red-hued nourishments may help in lessening foundational irritation and fortifying safe status by diminishing diseases.</strong> Food science ; Biology Dye analysis and toxicity ; Biochemical Analysis and Sensing Techniques
Authors: Henry Lloyd-Laney | Martin Robinson | Alan M. Bond | Alison Parkin | David J. Gavaghan
Source: ChemRxiv (preprint, 2020-11-30)
Field: Chemistry — Electrochemistry

A Spotter's Guide to Dispersion in Surface-Confined Voltammetry Experiments &lt;div&gt;This paper describes the effect of thermodynamic and kinetic dispersion on numerical simulations of three different surface-confined voltammetry experiments, ramped FTACV, Purely sinusoidal voltammetry (PSV) and direct current voltammetry (DCV), and the differences between the dispersed and non-dispersed cases. &lt;br&gt;&lt;/div&gt;&lt;div&gt;Dispersion in this case refers to a range of observed values for the thermodynamic driving force and reaction rate of a redox reaction (thermodynamic and kinetic dispersion respectively) . This has been acknowledged as a complicating factor of voltammetry experiments for some time. &lt;br&gt;&lt;/div&gt;&lt;div&gt;We demonstrate that thermodynamic dispersion has a far stronger effect than kinetic dispersion, and detail the ways in which kinetic dispersion can be resolved under such conditions. The work is novel in its comparison of three separate voltammetry techniques, and a focus on how to determine the presence of dispersion through computational analysis of experimental voltammetry data alone; previous work has required specific experiments designed to distinguish between dispersed and non-dispersed cases.&lt;/div&gt; Dispersion (optics) ; Voltammetry ; Cyclic voltammetry ; Kinetic energy ; Chemistry ; Work (physics) ; Redox ; Analytical Chemistry (journal) ; Thermodynamics ; Materials science ; Electrochemistry ; Electrode ; Physical chemistry ; Inorganic chemistry ; Physics ; Chromatography ; Optics ; Classical mechanics Electrochemical Analysis and Applications
Authors: C Ciofu | Grigoraș Cosmin-Constantin | Bogdan Chiriță | Iancu Cosmin Alexandru | Gheorghe Brabie
Source: Procedia Manufacturing (article, 2020-01-01)
Field: Materials Science — Biomaterials

Fracture Investigation in Draw Bending of AZ31B Sheets using Fuzzy Logic Prediction Automotive and aircraft industries are facing an increased demand of light-weighted materials for reducing fuel consumption and CO2 emissions. Magnesium alloy sheets are considered in manufacturing components of complex geometries and with flexible processes. Fracture investigation of AZ31B alloy sheets is of interest in continuous bending processes to achieve better formability. Certain forming processes of AZ31B sheets are restricted due to its limited ductility at room temperature. Draw bending of AZ31B sheets provides us the necessary forming state to investigate fracture limits. Our investigation relies on data extracted from draw bending tests organised according to a design of experiments plan. The experimental studies were conducted for different punch radii, traverse speeds and rolling directions. The predicted fracture behavior via Fuzzy Logic provides essential data to the setup procedures needed for our subsequent research, which is focusing on reducing the limitations of AZ31B sheets formability. Formability ; Bending ; Materials science ; Ductility (Earth science) ; Traverse ; Automotive industry ; Fracture (geology) ; Fuzzy logic ; Magnesium alloy ; Fuel efficiency ; Mechanical engineering ; Structural engineering ; Alloy ; Metallurgy ; Composite material ; Engineering ; Automotive engineering ; Computer science ; Creep Magnesium Alloys: Properties and Applications ; Metal Forming Simulation Techniques ; Aluminum Alloys Composites Properties
Authors: Roberto Peverati
Source:  (preprint, 2020-06-12)
Field: Chemistry — Spectroscopy

Fitting Elephants in the Density Functionals Zoo: Statistical Criteria for the Evaluation of DFT methods as a Suitable Replacement for Counting Parameters Counting parameters has become customary in the density functional theory community as a way to infer the transferability of popular approximations to the exchange–correlation functionals. Recent work in data science, however, has demonstrated that the number of parameters of a fitted model is not related to the complexity of the model itself, nor to its eventual overfitting. Using similar arguments, we show here that it is possible to represent every modern exchange–correlation functional approximation using just one single parameter. This procedure proves the futility of the number of parameters as a measure of transferability. To counteract this shortcoming, we introduce and analyze the performance of three statistical criteria for the evaluation of the transferability of exchange–correlation functionals. The three criteria are called Akaike information criterion (AIC), Vapnik–Chervonenkis criterion (VCC), and cross-validation criterion (CVC) and are used in a preliminary assessment to rank 60 exchange–correlation functional approximations using the ASCDB database of chemical data. Overfitting ; Akaike information criterion ; Measure (data warehouse) ; Correlation ; Transferability ; Computer science ; Rank (graph theory) ; Rank correlation ; Mathematics ; Data mining ; Machine learning ; Logit ; Combinatorics Molecular spectroscopy and chirality ; Functional Brain Connectivity Studies ; Spectroscopy and Quantum Chemical Studies
Authors: Defang Xu | Huamin Zhao | Shujuan Zhang | Chengji Li | Fei Zhao
Source: Journal of Spectroscopy (article, 2020-01-28)
Field: Chemistry — Analytical Chemistry

The Kinetic Model of the Peel Brittleness of Stored Cucumis Melons Based on Visible/Near-Infrared Spectroscopy A kinetic model based on visible/near-infrared spectroscopy of the peel brittleness of “Xintian-125” Cucumis melons, the research object, stored under room temperature, was established in order to realize real-time monitoring of the peel brittleness of Cucumis melons and for prediction of storage time. The NIR and peel brittleness of melons stored for 1, 4, and 7 days were collected and measured. SG was confirmed to be the best pretreatment by comparing the PLS models established with 4 pretreatment methods, and the differences of the prediction set determination coefficient and root-mean-square were 0.818 and 23.755, respectively. CARS and SPA were adopted to extract the feature wavelengths and establish the peel brittleness of PLS prediction model. The model’s prediction accuracy was 0.919, and the prediction root-mean-square was 25.413, indicating that NIR is able to realize the prediction of the peel brittleness of Cucumis melons. As a result, a NIR-based peel brittleness kinetic model was created. The <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"> <mi>P</mi> </math> value of the regression model was less than 0.001, and the model’s correlation coefficient was 0.8503, showing that the model is of extreme significance and high precision. The zero-order reaction equation was overfitted according to the variation tendency of the average peel brittleness of stored melons. The model’s correlation coefficient was 0.981, the standard error was 4.624, and the linear relation between the stored period and NIR was established based on it. The research proves that the NIR-based technology is able to realize quick and loss-free inspection of melons’ peel brittleness and prediction of the stored period. Cucumis ; Brittleness ; Correlation coefficient ; Coefficient of determination ; Materials science ; Mean squared error ; Root mean square ; Mathematics ; Physics ; Composite material ; Statistics ; Horticulture ; Biology Spectroscopy and Chemometric Analyses ; Water Quality Monitoring and Analysis ; Smart Agriculture and AI
Authors: Ka Un Lao | Yan Yang | Robert A. DiStasio
Source: ChemRxiv (preprint, 2020-09-11)
Field: Chemistry — Organic Chemistry

On the Higher-Order Static Polarizabilities and Dispersion Coefficients of the Fullerenes: An Ab Initio Study &lt;div&gt;In this work, we used finite-field derivative techniques and density functional theory (DFT) to compute the static isotropic polarizability series (&lt;i&gt;i.e.&lt;/i&gt;, dipole, quadrupole, and octupole ) for the C&lt;sub&gt;60&lt;/sub&gt;-C&lt;sub&gt;84&lt;/sub&gt; fullerenes and quantitatively assess the intrinsic non-additivity in these fundamental response properties. Critical analysis of the derived effective scaling laws provides new insight into how the electronic structure of finite-sized fullerenes---a unique dichotomy of electron confinement and delocalization effects due to their quasi-spherical cage-like structures and encapsulated void spaces---simultaneously limits &lt;i&gt;and&lt;/i&gt; enhances their quantum mechanical response to electric field perturbations. Corresponding molecular dispersion coefficients needed to describe the non-trivial van der Waals (vdW) interactions in fullerene-based systems were obtained by inputting the polarizabilities into the hollow sphere model within the modified single-frequency approximation. &lt;/div&gt;&lt;div&gt;Using first-order perturbation theory in conjunction with &gt;140,000 DFT calculations, we also computed the non-negligible zero-point vibrational contributions (zpvc) to the dipole polarizability in C&lt;sub&gt;60&lt;/sub&gt; and C&lt;sub&gt;70&lt;/sub&gt;, thereby enabling direct comparison between theory and experiment for these quintessential nanostructures.&lt;/div&gt; Polarizability ; van der Waals force ; Ab initio ; Density functional theory ; Fullerene ; Dipole ; Physics ; Perturbation theory (quantum mechanics) ; Quadrupole ; Molecular physics ; Chemistry ; Atomic physics ; Computational chemistry ; Quantum mechanics ; Molecule Fullerene Chemistry and Applications ; Advanced Physical and Chemical Molecular Interactions ; Boron and Carbon Nanomaterials Research
Authors: Soo-In Sohn | Young‐Ju Oh | Woo-Suk Cho | Yoonsung Cho | Eun-Kyoung Shin | Hyeon‐Jung Kang
Source: Korean Journal of Environmental Agriculture (article, 2020-09-24)
Field: Chemistry — Analytical Chemistry

Current Status of GM Crop Discrimination Technology Using Spectroscopy BACKGROUND: This paper describes the successful discrimination of GM crops from the respective wild type (WT) controls using spectroscopy and chemometric analysis. Despite the many benefits that GM crops, their development has raised concerns, particularly about their potential negative effects on food productionand the environment. From this point of view, the introduction of GM crops into the market requires the development of rapid and accurate identification technologies to ensure consumer safety. METHODS AND RESULTS: The development of a GM crop discrimination model using spectroscopy involved the pre-processing ofthe collected spectral information, the selection of a discriminant model, and the verification of errors. Examples of GM versus WT discrimination using spectroscopy are available for soybeans, tomatoes, corn, sugarcane, soybean oil, canola oil, rice, and wheat. Here, we found that not only discrimination but also cultivar grouping was possible. CONCLUSION: Since for the determination of GM crop there is no pre-defined pre-processing method or calibration model, it is extremely important to select the appro-priate ones to increase the accuracy in a case-by-case basis. Spectroscopy ; Crop ; Current (fluid) ; Materials science ; Engineering physics ; Engineering ; Geography ; Physics ; Forestry ; Electrical engineering ; Astronomy Spectroscopy and Chemometric Analyses ; Genetically Modified Organisms Research ; Microbial Metabolic Engineering and Bioproduction
Authors: Lestari Wardani | Noerati Noerati | Doni Sugiyana
Source: Jurnal Sains Materi Indonesia (article, 2020-12-15)
Field: Materials Science — Polymers and Plastics

CHARACTERIZATION OF COMPOSITE CONTAINING LDPE (LOW DENSITY POLY ETHYLENE) AND MODIFIED PINEAPPLE LEAF FIBER CHARACTERIZATION OF COMPOSITE CONTAINING LDPE ( LOW DENSITY POLY ETHYLENE) AND MODIFIED PINEAPPLE LEAF FIBER. Pineapple leaf fiber could be used as a reinforcing material in natural fiber composites production with a synthetic polymer matrix. The typical problem in this process was the weak bond between the fiber component and the matrix. This study aimed to improve the bonds strength between pineapple leaf fibers and the polymer matrix of LDPE (Low Density Poly Ethylene) by modifying pineapple leaf fibers. The modification of pineapple leaf fibers was carried out through an enzymatic process using the xylanase enzyme. A modified fiber was then used as a fiber component in the composite using a commercial LDPE plastic matrix. Composites were made by the sandwich method using a hotpress machine at a temperature of 130 °C for 10 minutes. The evaluation of the composites were carried out by testing the tensile strength properties using the Tensolab tool and thermal properties using the TGA (Thermal Gravimetry Analysis) instrument. The results of the mechanical properties test of the composite showed the modified pineapple leaf fiber-based composite had a better tensile strength (34.3 MPa) than the untreated pineapple leaf fiber-based composite (30.2 MPa). The results of the thermal properties test showed the decreasing of the mass occurred at temperature of 300-350 °C due to degradation of the fiber,and it completely degraded at temperature of 450 °C. Low-density polyethylene ; Materials science ; Composite material ; Composite number ; Fiber ; Ultimate tensile strength ; Ethylene ; Polyethylene ; Polymer ; Natural fiber ; Chemistry ; Organic chemistry Natural Fiber Reinforced Composites
Authors: Hong Chang | Wei Zhou
Source: Advances in Civil Engineering (article, 2020-01-01)
Field: Materials Science — Materials Chemistry

Stiffness and Crack Behavior of Unbonded Posttensioned Concrete Beam Strengthened with Aluminum Alloy Plate Corrosion resistance of aluminum alloy plates externally bonded by magnesium phosphate cement provides the ability to strengthen inshore infrastructures in harsh environments subject to moisture and humidity. In this study, the aim is to study the stiffness and cracking behavior of concrete beams using this strengthening technique. Six damaged unbonded posttensioned concrete beams were repaired and strengthened and then subjected to monotonic load until failure. This technique improved the stiffness and limited the development of cracks. The formula of elastic‐plastic stiffness coefficient related to the comprehensive reinforcement index was established. An influence coefficient δ considering the effect of aluminum alloy plates and unbonded tendons was introduced, and the crack expansion coefficient under short‐term load was obtained by statistical analysis. Finally, some simplified methods were proposed to evaluate the stiffness and cracks of unbonded posttensioned concrete beams strengthened with aluminum alloy plates. Materials science ; Stiffness ; Cracking ; Structural engineering ; Beam (structure) ; Alloy ; Composite material ; Corrosion ; Reinforcement ; Aluminium ; Engineering Magnesium Oxide Properties and Applications ; Structural Behavior of Reinforced Concrete ; Concrete Corrosion and Durability