jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Nimesh Mistry | Stephen P. Nicholson
Source: New Directions in the Teaching of Physical Sciences (article, 2020-07-24)
Field: Chemistry — Physical and Theoretical Chemistry

Investigating students understanding of organic reaction mechanisms from performing organic chemistry experiments The use of laboratory work to improve students’ knowledge of theory is one that is disputed. Student reflections of what they learn during practical work repeatedly show that students rarely think about theory. There is a lack of data that objectively compares students’ knowledge of theory where they complete an associated experiment to when they do not in order to understand if practical work does effect students’ knowledge of scientific concepts. In this work we aimed to address this gap by investigating the effect of students’ knowledge of organic mechanisms where they both perform and associated experiment and where they did not. Our results showed that organic chemistry experiments had no effect on students’ knowledge of organic mechanisms. These results support the view that there is little evidence to support the use of laboratory work to aid understanding of theory. Work (physics) ; Chemistry ; Computer science ; Mathematics education ; Psychology ; Physics ; Thermodynamics Various Chemistry Research Topics ; Science Education and Pedagogy ; Innovative Teaching Methods
Authors: Pepple Tamunosisi Furo | Jane Randy Abbey
Source: International Journal of Education and Social Science Research (article, 2020-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

OPPORTUNITY TO LEARN AND STUDENT ACADEMIC ENGAGEMENT AS CORRELATES OF STUDENTS’ ACHIEVEMENT IN CHEMISTRY IN RIVERS STATE The persistent poor performance of students in chemistry especially in external examinations such as WASSCE and NECO has been o (" great concern to parents, government and other stakeholders in education, and this is an indicator of students" poor acquisition of the necessary knowledge in chemistry. This could also be attributed to lack of opportunities to learn and poor student engagement in the school which tends to have affected the students' academic performance as well as their chances of gaining admission into Science. Technology and Mathematics (STM) related courses in the higher institutions. Hence, this study investigated the effect of opportunity to learn and student academic engagement on students" achievement in chemistry in Rivers State. The study adopted the correlational design of survey type. The population consisted of all the senior secondary school three (SSS 3) chemistry students in Rivers State. A sample size of 1000 respondents was selected using the simple random sampling technique. Three instruments were used for data collection which include, Chemistry Achievement Test (CAT) with 0.80 reliability coefficient using KR-20, Students' Opportunity To Learn Questionnaire (SOTLQ) and Student Academic Engagement Questionnaire (SAEQ) with 0.94 and 0.89 reliability coefficients respectively using Cronbach Alpha. Four research questions guided the study. Pearson Product Moment Correlation and Multiple Regression Analysis were employed for the data analysis. Result showed that opportunity to learn (r -0.044) and student academic engagement (r = 0.034) have positive but weak correlation with students' achievement in chemistry. Results also showed that opportunity to learn (r = 0.044, P > 0.05) and student academic achievement (r -0.034, P > 0.05) do not significantly correlate with students achievement in Chemistry. Two predictor variables jointly accounted for 0.4% of the total variance in students' achievement in Chemistry. Student engagement ; Academic achievement ; Mathematics education ; State (computer science) ; Student achievement ; Psychology ; Chemistry ; Computer science Various Chemistry Research Topics ; Online and Blended Learning ; Innovative Teaching Methods
Authors: Md. Masum Billah | Floran Martin | Anouar Belahcen
Source:  (article, 2020-08-23)
Field: Materials Science — Electronic, Optical and Magnetic Materials

A Computationally Effective Method for Iron Loss Estimation in a Synchronous Machine from a Static Field Solution In this paper, a computationally effective iron loss calculation method for synchronous machines is presented. The method is based on a single static 2D finite element field solution in the machine cross-section, which makes it much faster than the one based on the time-stepping solution. The developed method is applied to a salient pole synchronous machine, and the computational accuracy is validated against the time-stepping method. The proposed iron losses computation method showed a fair accuracy and a considerable speed-up of the computations. It can be an excellent alternative for the iron losses estimation in the optimization procedure of synchronous machines, where a considerable amount of finite element solutions needs to be carried out. Besides the losses comparison, local reconstruction of the time dependency of other quantities such as the magnetic vector potential and the magnetic flux density is reported for a better understanding of the method. Computation ; Finite element method ; Synchronous motor ; Computer science ; Magnetostatics ; Field (mathematics) ; Algorithm ; Control theory (sociology) ; Magnetic field ; Mathematics ; Engineering ; Artificial intelligence ; Structural engineering Magnetic Properties and Applications ; Electric Motor Design and Analysis
Authors: Ahmed Shaker Mohammed Tahir | Firas Monther Jassim
Source: International Journal on Advanced Science Engineering and Information Technology (article, 2020-08-12)
Field: Chemistry — Analytical Chemistry

Wavelet Estimation of Semi-parametric Regression Model The semi-parametric regression model combines parametric and nonparametric regression. However, non-parametric estimation may provide flexible solutions to the problems suffers by the regression model, but the problem of dimensionality that this estimator suffers, which occurs due to the increasing number of explanatory variables, still remain, this, in turn, may reduce the accuracy of the estimation process. Estimate the non-parametric part of the semi-parametric models that can be studied using conventional non-parametric methods such as the Spline Smoothing and Kernel Smoothing. However, there are other non-parametric methods that can be used, therefore, in this paper, the semi-parametric regression model was estimated by employing the wavelet estimate for the soft threshold, according to the "Speckman" method, and then comparing it with the two methods, Nadaraya-Watson and Local Linear, through the implementation of simulation experiments that included different sample sizes and threshold values. The parametric part estimation of the partially linear model according to the least-squares method was not identical to those estimates using the Speckman method, that is because the least-squares method was not appropriate for the uneven nature of the number of weekly work hours. Simulation experiments have demonstrated the efficiency of the wavelet estimation method and its superiority over other methods. The above estimation methods were applied to real data related to the study of the production value for the public industrial sector in Iraq, and some factors affect it, such as the value of industrial supplies, the total wages of workers, and the number of workers. Parametric statistics ; Semiparametric model ; Estimator ; Smoothing ; Mathematics ; Semiparametric regression ; Smoothing spline ; Parametric model ; Regression analysis ; Kernel regression ; Nonparametric regression ; Statistics ; Econometrics Spectroscopy and Chemometric Analyses ; Neural Networks and Applications ; Advanced Statistical Methods and Models
Authors: Ishwar N. Kohale | Danielle M. Burgenske | Ann C. Mladek | Katrina K. Bakken | Jenevieve Kuang | Judy C. Boughey | Liewei Wang | Jodi M. Carter | Eric B. Haura | Matthew P. Goetz | Jann N. Sarkaria | Forest M. White
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2020-09-11)
Field: Chemistry — Spectroscopy

Quantitative analysis of tyrosine phosphorylation from FFPE tissues reveals patient specific signaling networks Abstract Formalin fixed paraffin embedded (FFPE) tissues are an invaluable source of clinical specimens. Tyrosine phosphorylation (pTyr) plays a fundamental role in cellular processes and is commonly dysregulated in cancer but has not been studied to date in FFPE samples. We describe a method for quantitative analysis of pTyr signaling networks at an unprecedented sensitivity, with hundreds of sites quantified from 1-2 10-μm sections of FFPE tissue specimens. Phosphotyrosine profiles of flash frozen and FFPE tissues derived from the same tumors suggest that FFPE tissues preserve pTyr signaling characteristics in PDX tumors and archived clinical specimens. Differential activation of oncogenic proteins was observed in triple negative breast cancer tumors as well as lung cancer tumors, highlighting patient specific oncogenic driving kinases and indicating potential targeted therapies for each patient. These data highlight the capability for direct translational insight from pTyr analysis of small amounts of FFPE tumor tissue specimens. Phosphorylation ; Cancer research ; Tyrosine phosphorylation ; Signal transduction ; Lung cancer ; Biology ; Tyrosine ; Cancer ; Tyrosine kinase ; Pathology ; Molecular biology ; Medicine ; Cell biology ; Biochemistry ; Genetics Advanced Proteomics Techniques and Applications ; Bioinformatics and Genomic Networks ; Protein Tyrosine Phosphatases
Authors: Fatemeh Ghassempour Nikfarjam | Mohammad Mahmoodi Hashemi | Ali Ezabadi
Source: Journal of Nanomedicine (article, 2020-05-05)
Field: Chemistry — Organic Chemistry

One-pot synthesis of biologically important xanthene derivatives using [(Et3 N)2 SO][HSO4 ]2 as a novel and green IL-based catalyst under solvent-free conditions One-pot synthesis of biologically important xanthene derivatives using [(Et 3 N) 2 SO][HSO 4 ] 2 as a novel and green IL-based catalyst under solvent-free conditions Xanthene ; Catalysis ; Chemistry ; Solvent ; Organic chemistry ; Combinatorial chemistry Multicomponent Synthesis of Heterocycles ; Synthesis and biological activity ; Synthesis of Organic Compounds
Authors: Benjamin Laroche | Thomas Bouvarel | Martin Louis-Sylvestre | Bastien Nay
Source: Beilstein Journal of Organic Chemistry (article, 2020-04-28)
Field: Chemistry — Organic Chemistry

Diversity-oriented synthesis of 17-spirosteroids A diversity-oriented synthesis (DOS) approach has been used to functionalize 17-ethynyl-17-hydroxysteroids through a one-pot procedure involving a ring-closing enyne metathesis (RCEYM) and a Diels-Alder reaction on the resulting diene, under microwave irradiations. Taking advantage of the propargyl alcohol moiety present on commercially available steroids, this classical strategy was applied to mestranol and lynestrenol, giving a collection of new complex 17-spirosteroids. Enyne metathesis ; Moiety ; Ring-closing metathesis ; Diene ; Metathesis ; Propargyl ; Diversity (politics) ; Combinatorial chemistry ; Chemistry ; Stereochemistry ; Organic chemistry ; Catalysis Synthetic Organic Chemistry Methods ; Chemical Synthesis and Analysis ; Marine Sponges and Natural Products
Authors: Chandra Kanth Bandi | A. Pedro Gonçalves | Sai Venkatesh Pingali | Shishir P. S. Chundawat
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2020-05-08)
Field: Chemistry — Organic Chemistry

Carbohydrate binding domains facilitate efficient oligosaccharides synthesis by enhancing mutant catalytic domain transglycosylation activity Abstract Chemoenzymatic approaches using carbohydrate-active enzymes (CAZymes) offer a promising avenue for synthesis of glycans like oligosaccharides. Here, we report a novel chemoenzymatic route for cellodextrins synthesis employed by chimeric CAZymes, akin to native glycosyltransferases, involving the unprecedented participation of a ‘non-catalytic’ lectin-like or carbohydrate-binding domains (CBMs) in the catalytic step for glycosidic bond synthesis using β-cellobiosyl donor sugars as activated substrates. CBMs are often thought to play a passive substrate targeting role in enzymatic glycosylation reactions mostly via overcoming substrate diffusion limitations for tethered catalytic domains (CDs) but are not known to participate directly in any nucleophilic substitution mechanisms that impact the actual glycosyl transfer step. Our study provides evidence for the direct participation of CBMs in the catalytic reaction step for β-glucan glycosidic bonds synthesis enhancing activity for CBM-based CAZyme chimeras by &gt;140-fold over CDs alone. Dynamic intra-domain interactions that facilitate this poorly understood reaction mechanism were further revealed by small-angle X-ray scattering structural analysis along with detailed mutagenesis studies to shed light on our current limited understanding of similar transglycosylation-type reaction mechanisms. In summary, our study provides a novel strategy for engineering similar CBM-based CAZyme chimeras for synthesis of bespoke oligosaccharides using simple activated sugar monomers. Glycosidic bond ; Glycosylation ; Chemistry ; Glycoside hydrolase ; Glycosyltransferase ; Glycan ; Biochemistry ; Carbohydrate-binding module ; Combinatorial chemistry ; Enzyme ; Glycoprotein Carbohydrate Chemistry and Synthesis ; Glycosylation and Glycoproteins Research ; Enzyme Production and Characterization
Authors: Yanbao Yu | Linhong Jing | Maria Warren Hines | Xian Chen | Nedyalka Dicheva | Carol E. Parker | David Seo | Geoffrey S. Ginsburg | Debra A. Schwinn
Source: UNC Libraries (article, 2020-11-08)
Field: Chemistry — Spectroscopy

Discovery of biomarker candidates for coronary artery disease from an APOE-knock out mouse model using iTRAQ-based multiplex quantitative proteomics Due to the lack of precise markers indicative of its occurrence and progression, coronary artery disease (CAD), the most common type of heart diseases, is currently associated with high mortality in the United States. To systemically identify novel protein biomarkers associated with CAD progression for early diagnosis and possible therapeutic intervention, we employed an iTRAQ-based quantitative proteomic approach to analyze the proteome changes in the plasma collected from a pair of wild type versus apolipoprotein E knockout (APOE −/−) mice which were fed with a high fat diet. In a multiplex manner ITRAQ serves as the quantitative ‘in-spectra’ marker for ‘cross-sample’ comparisons to determine the differentially expressed/secreted proteins caused by APOE knock-out. To obtain the most comprehensive proteomic datasets from this CAD-associated mouse model we applied both MALDI and ESI-based mass spectrometric (MS) platforms coupled with two different schemes of multidimensional liquid chromatography (2D-LC) separation. We then comparatively analyzed a series of the plasma samples collected at six and twelve weeks after the mice were fed with fat diets, where the 6-week or 12-week time point represents the early or intermediate phase of the fat-induced CAD, respectively. We then categorized those proteins showing abundance changes in accordance with APOE depletion. Several proteins such as the gamma and beta chains of fibrinogen, apolipoprotein B, apolipoprotein C-I, and thrombospondin-4 were among the previously known CAD markers identified by other methods. Our results suggested that these unbiased proteomic methods are both feasible and a practical means of discovering potential biomarkers associated with CAD progression. Multiplex ; Biomarker ; Proteomics ; Apolipoprotein E ; Biomarker discovery ; Computational biology ; Disease ; Medicine ; Biology ; Bioinformatics ; Internal medicine ; Gene ; Genetics Advanced Proteomics Techniques and Applications ; Atherosclerosis and Cardiovascular Diseases
Authors: A. Fabricius | Alessandro Catanzaro | Alessandro Cultrera
Source: arXiv (Cornell University) (preprint, 2020-07-27)
Field: Materials Science — Materials Chemistry

Good Practice Guide on the electrical characterisation of graphene using contact methods This guide is a deliverable of the Joint Research Project 16NRM01 GRACE -- Developing electrical characterisation methods for future graphene electronics. The project belongs to the European Metrology Programme for Innovation and Research (EMPIR). GRACE is framed within the Normative targeted program, and its overall goal is (1) the development of validated protocols for the measurement of the electrical properties of graphene, and their implementation in order to achieve accurate and fastthroughput measurement of graphene; and (2) the collaboration with international standardisation committees in order to initiate and develop dedicated documentary standards for the electrical characterisation of graphene. The adoption of this GPGs and, when published, the corresponding standards, will allow industry to perform accurate measurements of the electrical properties of graphene and thereby provide customers with reliable and comparable specifications of graphene as an industrial product. Graphene ; Deliverable ; Normative ; Systems engineering ; Nanotechnology ; Metrology ; Electronics ; Order (exchange) ; Product (mathematics) ; Computer science ; Materials science ; Business ; Engineering ; Electrical engineering ; Physics ; Political science Graphene research and applications ; Surface and Thin Film Phenomena ; Nanopore and Nanochannel Transport Studies
Authors: Venkata Sai Dheeraj Munjulury | Robertina Calico
Source: Journal of Drug Delivery and Therapeutics (article, 2020-12-15)
Field: Materials Science — Biomaterials

Assessment of Modern Excipients in Controlled Delivery of Proteins and Peptides Polymeric micelles are highly proficient of modulating the function, distribution of drugs in the body, and can overcome biological barriers hence provoked as novel nanomedicine via various formulations. Current review emphasis on application of several polymers, biomaterials, lipids for the preparation of polymeric micelles formed by several molecular interactions between the block co-polymers and encapsulated molecules. Micellar carriers will be selected on basis of the type of polymer/payload interaction, which includes biological interface focused on the internal chemistry and fabrication of block-co polymers. Several features of these carriers can be manipulated to catering a broad range of drugs through active sensing of body targets. The fine-tuning of their properties in response to particular stimuli, modulating the activity of the loaded drugs at the targeted sites, even at the subcellular level. To end with, the future perspective and impending challenges for polymeric micelles as nanomedicine are elaborated, anticipating prompting further innovations. Keywords: Proteins, Peptides, Co-block Polymers, Lipids, Controlled, Drug Delivery. Nanomedicine ; Micelle ; Nanotechnology ; Drug delivery ; Polymer ; Chemistry ; Materials science ; Combinatorial chemistry ; Nanoparticle ; Organic chemistry ; Aqueous solution Nanoparticle-Based Drug Delivery ; Advanced Drug Delivery Systems ; RNA Interference and Gene Delivery
Authors: Dawei Li | Man-Man Ding | Yu Ge | David Felipe Tello Yepes | Mingyuan Sun | Muhammad Saleem Najib | Yahong Li | Yi‐Quan Zhang | Jinlei Yao
Source: New Journal of Chemistry (article, 2020-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Assembling two Dy<sub>2</sub> single-molecule magnets with different energy barriers <i>via</i> fine-tuning the geometries of Dy<sup>III</sup> sites Two Dy<sub>2</sub> single-molecule magnets are prepared. The energy barrier of <bold>2</bold> is slightly enhanced by adjusting the geometries of Dy<sup>III</sup> centers. Chemistry ; Magnet ; Molecule ; Dysprosium ; Lanthanide ; Nanotechnology ; Crystallography ; Inorganic chemistry ; Ion ; Physics ; Organic chemistry Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Advanced NMR Techniques and Applications
Authors: Bat‐hen Eylon | Alona Shagan | Ayelet Shabtay‐Orbach | Adi Gross | Boaz Mizrahi
Source: Advanced NanoBiomed Research (article, 2020-12-10)
Field: Materials Science — Biomaterials

Injectable Drug Delivery System Based on In Situ Self‐Assembly of Liquid Star Polyethylene Glycol–Poly(lactic‐<i>co</i>‐glycolic acid) Particulate systems are widely used in biomedical applications, yet current systems are limited by their stability, complicated production processes, and the use of toxic excipients and cosolvents. Here, a new concept for an injectable nanocarrier system based on the in situ self‐assembled star polyethylene glycol (PEG)– poly(lactic‐ co ‐glycolic acid) (PLGA)/drug mixture is presented. The new injectable material is based on a neat (solvent‐free) liquid copolymer that self‐assembles after it is injected along with the drug to form a particulate delivery system. The nanocarriers’ formation rate and encapsulation capabilities of hydrophobic drugs can be fine‐tuned by changing the molecular weight of the PLGA segment. Furthermore, the starPEG–PLGA‐based system demonstrates potential as a drug carrier for hydrophobic drugs and shows biocompatibility with cell line culture. PLGA ; Nanocarriers ; Polyethylene glycol ; Biocompatibility ; Drug delivery ; Glycolic acid ; Lactic acid ; Chemical engineering ; Copolymer ; PEG ratio ; Chemistry ; Materials science ; Nanotechnology ; Organic chemistry ; Nanoparticle ; Polymer Nanoparticle-Based Drug Delivery ; Advanced Drug Delivery Systems ; Hydrogels: synthesis, properties, applications
Authors: G. Santosh
Source: Asian Journal of Chemistry (article, 2020-01-31)
Field: Materials Science — Materials Chemistry

Porphyrins with Five-Membered Ring Substituents on meso-Position and their Derivatives Tetrapyrrolic porphyrins are the molecules of choice for nature where light absorption and metal based chemistry plays an important role in biological systems. Constant efforts are directed at modifying the porphyrin skeletal structure to result in porphyrins with fine-tuned physical properties. This review focusses on the chemistry of porphyrins with five-membered aromatic rings such as furan, pyrrole and thiophene as substituents at the meso position of porphyrins. Substitution with these five-membered rings at the meso-position of porphyrins brings about significant modulation of HOMO-LUMO gap, which reflects in shifts in the absorption and fluorescence spectra and in their electrochemical properties compared to the conventional porphyrins with six-membered aryl substituents. The synthetic modification of these five-membered rings by introdcution of various functional groups were also discussed. Chemistry ; Porphyrin ; Thiophene ; Pyrrole ; Furan ; Ring (chemistry) ; HOMO/LUMO ; Photochemistry ; Electrochemistry ; Aryl ; Molecule ; Absorption (acoustics) ; Stereochemistry ; Organic chemistry ; Physical chemistry Porphyrin and Phthalocyanine Chemistry ; Luminescence and Fluorescent Materials ; Photochemistry and Electron Transfer Studies