jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Niraj Kumar Singh | Monika Kumari | Manodipan Sahoo
Source: IEEE Access (article, 2020-01-01)
Field: Materials Science — Materials Chemistry

A Compact Short-Channel Analytical Drain Current Model of Asymmetric Dual-Gate TMD FET in Subthreshold Region Including Fringing Field Effects A compact drain current model is developed for an asymmetric, dual gate, monolayer 2 - D Transition metal dichalcogenide (TMD) field effect transistor (FET) in the subthreshold region. The work includes the effect of source to drain tunneling and gate dielectric fringing effects. The model is systematically derived for an asymmetric, dual gate structure. The model developed is also extended into a dual-gate symmetric structure. The characteristic length expression has only physical and dimensional parameters including the contribution of fringing field effects from both front and back gate dielectric. The model is validated with simulation results obtained using NEGF based nanodevice simulators and experimental data of WSe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> p-channel FET. Also, transfer characteristics, output characteristics, subthreshold swing and output resistance are compared with reported data in literatures. A close agreement is observed with some disparity arising because of the non-inclusion of back gate fringing effects and source to drain tunneling in their models. The proposed model captures the effects of different high-κ gate dielectric materials and its thicknesses. Impact of temperature is also studied on transfer characteristics. The model is also scalable from ultrashort channel regime to long channel regime. Finally, the model can be applicable not only for TMD materials but other 2 - D materials also. Gate dielectric ; Quantum tunnelling ; Field-effect transistor ; Subthreshold conduction ; Metal gate ; Optoelectronics ; Dielectric ; Subthreshold slope ; Materials science ; Transistor ; Physics ; Gate oxide ; Quantum mechanics 2D Materials and Applications ; Nanowire Synthesis and Applications ; Ferroelectric and Negative Capacitance Devices
Authors: Nader Noroozi Pesyan | Narmin Akhteh | Hana Batmani | Barış Anıl | Ertan Şahi̇n
Source: Heterocyclic Communications (article, 2020-01-01)
Field: Chemistry — Organic Chemistry

A Facile and Catalyst-free Synthesis of Hexahydroacridine-1,8(2 <i>H</i> ,5 <i>H</i> )-dione and Octahydroacridin-10(1 <i>H</i> )-yl)thiourea Derivatives: Inter- and Intramolecular Aza-Michael addition Abstract An easy and convenient technique for the one-pot synthesis of novel compounds of hexahydroacridine-1,8(2 H ,5 H )-dione and octahydroacridin-10(1 H )-yl) thiourea derivatives has been developed by the reaction of the octahydro-1 H -xanthenes with hydroxylamine hydrochloride and thiosemicarbazide in ethylene glycol, which is a green solvent, under mild reaction conditions. IR, 1 H NMR, 13 C NMR spectrometry, and X-ray diffraction analysis were used to identify the structures of these compounds. Chemistry ; Thiourea ; Hydroxylamine Hydrochloride ; Ethylene glycol ; Catalysis ; Intramolecular force ; Proton NMR ; Carbon-13 NMR ; Medicinal chemistry ; Hydrochloride ; Organic chemistry Synthesis and biological activity ; Multicomponent Synthesis of Heterocycles ; Bioactive Compounds and Antitumor Agents
Authors: André Souza | Fábio Cardoso | Lucas Sousa Martins | Cláudio Alves | José Rogério A. Silva | Fábio Alberto de Molfetta
Source: Journal of the Brazilian Chemical Society (article, 2020-08-06)
Field: Chemistry — Organic Chemistry

Molecular Modelling Study of Heteroarylamide/Sulfonamide Compounds with Antitrypanosomal Activity According to the World Health Organization (WHO), Chagas disease (CD), whose etiological agent is the Trypanosoma cruzi (T. cruzi) parasite, affects about eight million people, mainly in Latin America. The cruzain enzyme is highlighted among the main biological targets, since it is the most abundant of the cysteine protease class from T. cruzi and is involved in the entire life cycle of the parasite, essential in regulating the interaction between parasite and host. The drugs available for the treatment of CD usually have strong side effects, and the nitro(triazole/imidazole)based heteroarylamide/sulfonamide compounds (HA/S) emerge with high antitrypanosomal potential. In this study, the quantitative structure-activity relationship (QSAR) were built using partial least squares (PLS) regression, and the results were robust and adequate for predicting and proposing five new derivatives according to the statistical parameters. The docking results suggest that the best-scored HA/S derivatives showed hydrogen bonds with the residuals that comprise the catalytic region of the enzyme. The molecular dynamics (MD) simulations, performed with different methods, revealed the strong stability of the compound obtained by the QSAR model of this study, in addition to a better binding free energy value than the HA/S obtained from literature. Sulfonamide ; Chemistry ; Stereochemistry Synthesis and biological activity
Authors: Rudolf Naef
Source: Preprints.org (preprint, 2020-02-06)
Field: Chemistry — Organic Chemistry

Calculation of the Isobaric Heat Capacities of the Liquid and Solid Phase of Organic Compounds at 298.15K by Means of a Generally Applicable Computer Algorithm Based on the Group-Additivity Method The calculation of the isobaric heat capacities of the liquid and solid phase of molecules at 298.15 K is presented, applying a universal computer algorithm based on the atom-groups additivity method, using refined atom groups. The atom groups are defined as the molecules' constituting atoms and their immediate neighbourhood. In addition, the hydroxy group of alcohols are further subdivided to take account of the different intermolecular interactions of primary, secondary and tertiary alcohols. The evaluation of the groups' contributions has been carried out by means of a fast Gauss-Seidel fitting calculus using experimental data from literature. Plausibility has been tested immediately after each fitting calculation using a 10-fold cross-validation procedure. For the heat capacity of liquids, the respective goodness of fit of the direct (R2) and the cross-validation calculations (Q2) of 0.998 and 0.9975, and the respective standard deviations of 8.2 and 9.16 J/mol/K, together with a medium absolute percentage deviation (MAPD) of 2.69%, based on the experimental data of 1133 compounds, proves the excellent predictive applicability of the present method. The statistical values for the heat capacity of solids are only slightly inferior: for R2 and Q2, the respective values are 0.9915 and 0.9875, the respective standard deviations are 12.19 and 14.13 J/mol/K and the MAPD is 4.65%, based on 732 solids. The predicted heat capacities for a series of liquid and solid compounds has been directly compared to those received by a complementary method based on the "true" molecular volume [1] and their deviations elucidated. Isobaric process ; Additive function ; Heat capacity ; Chemistry ; Thermodynamics ; Molecule ; Atom (system on chip) ; Intermolecular force ; Standard deviation ; Mathematics ; Organic chemistry ; Physics ; Statistics ; Mathematical analysis Chemical Thermodynamics and Molecular Structure ; Phase Equilibria and Thermodynamics ; Thermodynamic properties of mixtures
Authors: Manuel J. S. Farias | Adilson L. P. Silva | Auro Atsushi Tanaka | Enrique Herrero | Juan M. Feliú
Source: The Journal of Physical Chemistry C (article, 2020-11-23)
Field: Materials Science — Materials Chemistry

Surface Defects as Ingredients That Can Improve or Inhibit the Pathways for CO Oxidation at Low Overpotentials Using Pt(111)-Type Catalysts All scientific reports regarding the electro-oxidation reaction of CO on Pt electrodes, without exception, show that this reaction is favored on Pt surfaces rich in defects. In fact, “ordinary” or simple CO preoxidation is a typical process of surface-defected catalysts obeying the conditions of a full COads layer formed at suitably low potentials, such as those of the hydrogen underpotential deposition region. Among the Pt(111)-type surfaces, nondefected Pt(111) has the lowest catalytic activity for CO electro-oxidation. As a novelty, this paper reports that an unusual CO preoxidation appears on a nondefected Pt(111) surface, depending on the COads layer preparation, that is, for a COads layer prepared by cooling the flame-annealed Pt(111) electrode in a CO atmosphere. The magnitude of this unusual CO preoxidation decreases as the Pt surface becomes rich in steps (defects), and using stepped surfaces, this unusual stage of CO electro-oxidation at low overpotentials is revealed to be connected with a long-range order on the (111) plane. Interestingly, both ordinary and unusual CO preoxidations take place on the (111) terrace domains, but only ordinary CO preoxidation is favored on surfaces rich in defects. We propose a mechanism of indirect participation of defects in catalysis, according to which, at low overpotentials, defects on the surface act as ingredients that can improve or inhibit the pathways for the CO electro-oxidation reaction but do not serve as the most active sites themselves. Therefore, at least on extended platinum surfaces, there is no general condition whereby surface defects always favor the CO electro-oxidation reaction. From experiments at temperatures ranging from 283 to 313 K, the activation energies for the unusual CO preoxidation and the main CO oxidation processes were about 108 and 117 kJ mol–1, respectively. Furthermore, it was found that the increase of the CO stripping temperature caused a proportionally greater reduction of charge density of the CO electro-oxidation processes at low overpotentials, that is, the unusual CO preoxidation, in comparison with the charge density of the oxidation of CO at the main peak (at higher overpotentials). Catalysis ; Chemical engineering ; Materials science ; Type (biology) ; Chemistry ; Inorganic chemistry ; Biochemistry ; Geology ; Engineering Catalytic Processes in Materials Science ; Electrocatalysts for Energy Conversion ; Catalysis and Oxidation Reactions
Authors: Yuliia Matiichuk | Yu. V. Ostapiuk | Taras Chaban | В. В. Огурцов | V. S. Matiychuk
Source: Biopolymers and Cell (article, 2020-02-29)
Field: Chemistry — Organic Chemistry

Synthesis and anticancer properties of N-(5-R-benzyl-1,3-thiazol-2-yl)-2,5-dimethyl-3-furamides Aim. Study of the synthesis and anticancer activity of a series of N-(5-R-benzyl-1,3-thiazol-2-yl)-2,5-dimethyl-3-furamides. Methods. Organic synthesis, analytical and spectral methods, pharmacological screening. Results. N-(5-R-benzyl-1,3-thiazol-2-yl)-2,5-dimethyl-3-furamides 7a-g have been prepared in good yields by the reaction of 2-amino-5-(R-benzyl)thiazoles with 2,5-dimethyl-3-furoylchloride. Their structure was confirmed by 1 H NMR spectroscopy and microanalyses. The synthesized compounds have been evaluated for their anticancer activity against 60 cancer lines in the concentration of 10 M. The human tumour cell lines were derived from nine different cancer types: leukemia, melanoma, lung, colon, CNS, ovarian, renal, prostate, and breast cancers. It was found that compounds 7d,e,g exhibit a high activity with GP = 29.05-35.02 % whereas 7a-c,f -moderate activity with GP = 60.31-67.36 %. The most active compound 7g showed a high inhibition activity (GI 50 <10 M) against 54 of 58 human tumor cell lines with average GI 50 values of 4.22 M and the colon cancer subpanel demonstrated the highest sensitivity with [a] mean GI 50 value of 2.53 M. The most sensitive line was T-47D (BreastCancer, GI 50 = 0.088 M). [The] MG-MID values for the most active compound 7g are less compared with those for 5-fluorouracil, curcumin and cisplatin when testing in the same manner. Conclusions. A series of new N-(5-R-benzyl-1,3-thiazol-2-yl)-2,5dimethyl-3-furamides were prepared. The compounds with high anticancer activity have been identified. Chemistry ; Medicinal chemistry ; Combinatorial chemistry Synthesis and biological activity ; Synthesis and Characterization of Heterocyclic Compounds ; Synthesis and Reactions of Organic Compounds
Authors: Samir M. El Rayes | Ahmed Aboelmagd | Mohamed S. Gomaa | Walíd Fathalla | Imran Ali | Faheem Hyder Pottoo | Firdos Alam Khan
Source: RSC Advances (article, 2020-01-01)
Field: Chemistry — Organic Chemistry

Newly synthesized 3-(4-chloro-phenyl)-3-hydroxy-2,2-dimethyl-propionic acid methyl ester derivatives selectively inhibit the proliferation of colon cancer cells A series of 24 compounds were synthesized based on structure modification of the model methyl-3-(4-chlorophenyl)-3-hydroxy-2,2-dimethylpropanoate as potent HDACIs. Saponification and hydrazinolysis of the model ester afforded the corresponding acid and hydrazide, respectively. The model ester was transformed into the corresponding trichloroacetimidate or acetate by the reaction with trichloroacetonitrile and acetic anhydride, respectively. <i>N</i>-Alkyl-3-(4-chlorophenyl)-3-hydroxy-2,2-dimethylpropan-amides and methyl-2-[(3-(4-chlorophenyl)-3-hydroxy-2,2-dimethylpropanoyl)amino] alkanoates were obtained by the reaction of corresponding acid or hydrazide with amines and amino acid esters <i>via</i> DCC and azide coupling methods. Methyl-3-aryl-3-(4-chlorophenyl)-2,2-dimethylpropanoates were obtained in good yields and short reaction time from the corresponding trichloroacetimidate or acetate by the reaction with C-active nucleophiles in the presence of TMSOTf (0.1 eq.%) <i>via</i> C-C bond formation. The antiproliferative and apoptotic activity were further studied with molecular docking. The 48 post-treatments showed that out of 24 compounds, 12 compounds showed inhibitory actions on HCT-116 cells, we have calculated the inhibitory action (IC<sub>50</sub>) of these compounds on HCT-116 and we have found that the IC<sub>50</sub> values were in between 0.12 mg mL<sup>-1</sup> to 0.81 mg mL<sup>-1</sup>. The compounds (7a & 7g) showed highest inhibitory activity (0.12 mg mL<sup>-1</sup>), whereas compound 7d showed the lowest inhibitory activity (0.81 mg mL<sup>-1</sup>). We have also examined inhibitory action on normal and non-cancerous cells (HEK-293 cells) and confirmed that action of these compounds was specific to cancerous cells. The cancerous cells were also examined for nuclear disintegration through staining with DAPI, (4',6-diamidino-2-phenylindole) is a blue-fluorescent DNA stain, and we have found that there was loss of DAPI staining in the compound treated cancerous cells. The compounds were found to potentially act through the HSP90 and TRAP1 mediated signaling pathway. Compounds 7a and 7g showed the highest selectivity to TRAP1 which explained its superior activity. Chemistry ; Hydrazide ; Saponification ; Acetic anhydride ; Acetic acid ; Aryl ; IC50 ; Azide ; Pyrimidine ; Stereochemistry ; Nucleophile ; Alkyl ; Medicinal chemistry ; In vitro ; Organic chemistry ; Catalysis ; Biochemistry Synthesis and biological activity ; Click Chemistry and Applications ; Computational Drug Discovery Methods
Authors: Mariana Cruz Almeida | Rita Branco | Paula V. Morais
Source: PLoS ONE (article, 2020-02-24)
Field: Chemistry — Inorganic Chemistry

Response to vanadate exposure in Ochrobactrum tritici strains Vanadium is a transition metal that has been added recently to the EU list of Raw Critical Metals. The growing needs of vanadium primarily in the steel industry justify its increasing economic value. However, because mining of vanadium sources (i. e. ores, concentrates and vanadiferous slags) is expanding, so is vanadium environmental contamination. Bioleaching comes forth as smart strategy to deal with supply demand and environmental contamination. It requires organisms that are able to mobilize the metal and at the same time are resistant to the leachate generated. Here, we investigated the molecular mechanisms underlying vanadium resistance in Ochrobactrum tritici strains. The highly resistant strain 5bvl1 was able to grow at concentrations > 30 mM vanadate, while the O. tritici type strain only tolerated < 3 mM vanadate concentrations. Screening of O. tritici single mutants (chrA, chrC, chrF and recA) growth during vanadate exposure revealed that vanadate resistance was associated with chromate resistance mechanisms (in particular ChrA, an efflux pump and ChrC, a superoxide dismutase). We also showed that sensitivity to vanadate was correlated with increased accumulation of vanadate intracellularly, while in resistant cells this was not found. Other up-regulated proteins found during vanadate exposure were ABC transporters for methionine and iron, suggesting that cellular responses to vanadate toxicity may also induce changes in unspecific transport and chelation of vanadate. Vanadate ; Vanadium ; Efflux ; Chemistry ; Biology ; Biochemistry ; Inorganic chemistry Vanadium and Halogenation Chemistry ; Metal-Catalyzed Oxygenation Mechanisms ; Heme Oxygenase-1 and Carbon Monoxide
Authors: Hilal Torul | Nurgün Küçükboyacι | Uğur Tamer | Çi̇men Karasu
Source: Journal of Research in Pharmacy (article, 2020-07-16)
Field: Chemistry — Organic Chemistry

Evaluation of phenolic compounds and protective effects of olive (Olea europaea L.) leaf extracts on endothelial cells against hydrogen peroxide-induced toxicity Olea europaea L. (Oleaceae) leaves have been used for centuries in folk medicine to treat many degenerative and inflammatory diseases including hypertension, atherosclerosis and cardiovascular disorders. The present study was aimed to quantify the phenolic compounds present in three different extracts of O. europaea leaves, and to demonstrate their protective effects on human umbilical vein endothelial cells against oxidative injury induced by H2O2. Oleuropein, hydroxytyrosol, quercetin, luteolin and rutin in the olive leaf extracts were quantified by using a validated HPLC-UV method. Total phenolic content was determined using the Folin-Ciocalteau assay. The MTT and dichlorofluorescein assays were conducted to measure cytotoxicity and intracellular reactive oxygen species generation, respectively. Oleuropein was the major phenolic component. Each phenolic compound (1.0 and 10.0 M) and each extract (10.0 g/mL) significantly (p<0.05) preserved human umbilical vein endothelial cells against H2O2induced toxicity, but olive leaf extract-1 and luteolin seemed to be more effective in studied concentrations even in the inhibition of cellular reactive oxygen species generation (p<0.05). In addition, a positive correlation was found between reactive oxygen species inhibitory activity and total phenol content versus viability protecting capacity of each olive leaf extracts. These results supply a new validated HPLC method for the effective characterization of olive leaf polyphenolic compounds and support the notion that the polyphenolic components of olive leaves are the efficient cytoprotective agents against H2O2-induced oxidative stress and toxicity in human umbilical vein endothelial cells. Olea ; Hydrogen peroxide ; Chemistry ; Toxicity ; Botany ; Biology ; Biochemistry ; Organic chemistry Edible Oils Quality and Analysis
Authors: Ali Kermanizadeh | Nicklas Raun Jacobsen | Fiona Murphy | Leagh Powell | Lee Parry | Haiyuan Zhang | Peter Möller
Source: Advanced Therapeutics (review, 2020-11-09)
Field: Materials Science — Biomaterials

A Review of the Current State of Nanomedicines for Targeting and Treatment of Cancers: Achievements and Future Challenges Abstract The design and utilization of nanomedicines offers great potential for treating various diseases including cancers. Current challenges with traditional cancer treatment strategies include but are not limited to lack of specific targeting, overt systemic toxicity and low efficacy. The use of nanomaterials show particular promise as candidates for cancer treatment due to their high surface to volume ratio and tuneable size, shape, and surface chemistry, which in combination, allow for improved tumor targeting and enhanced therapeutic efficacy. The scrutinization of the literature demonstrates the potential of nanosized carrier systems over traditional approaches (at the molecular level) for specific targeting of the tumors. Despite the great promise showing in preclinical studies, the number of nanomedicines reaching clinical testing is still very low. This review attempts to address this issue by using a weight of evidence approach to the different strategies for use of nanomedicines in combating cancer, as well as highlighting a number of areas that the field of nanomedicines is clearly lagging behind in, as compared to conventional drug discovery and development. It is hoped that the recommendations in this review will allow for better translation of nanomedicines reaching clinical trials. Nanomedicine ; Cancer ; Clinical trial ; Cancer treatment ; Medicine ; Nanotechnology ; Risk analysis (engineering) ; Materials science ; Internal medicine Nanoparticle-Based Drug Delivery ; Nanoplatforms for cancer theranostics ; RNA Interference and Gene Delivery
Authors: Henry Shere | Michael S. Hill | Anne‐Frédérique Pécharman | Mary F. Mahon
Source: Dalton Transactions (article, 2020-12-11)
Field: Chemistry — Organic Chemistry

Reactivity of a magnesium diboranate with organic nitriles A series of complexes generated through reactions of the β-diketiminato magnesium diboranate species, [(BDI)Mg{(n-Bu)pinB-Bpin}] (BDI = HC{(Me)CNDipp}2; Dipp = 2,6-di-iso-propylphenyl), and a variety of organic nitriles are reported. Although, in every case, the diboranate anion acts as a surrogate source of the {Bpin} nucleophile, resulting in B-C bond formation at the electrophilic sp-hydridised nitrile carbon, the resultant compounds display a variable propensity to undergo subsequent reaction with additional nitrile equivalents. This behaviour is rationalised to be a consequence of substituent-dependent modulation in the basicity and resultant electrophilicity of magnesium-coordinated nitrile intermediates. Nitrile ; Electrophile ; Substituent ; Chemistry ; Reactivity (psychology) ; Magnesium ; Medicinal chemistry ; Organic chemistry ; Photochemistry ; Catalysis Organoboron and organosilicon chemistry ; Synthesis and characterization of novel inorganic/organometallic compounds ; Coordination Chemistry and Organometallics
Authors: Samuel V. Glass | Samuel L. Zelinka | Emil Engelund Thybring
Source: Cellulose (article, 2020-11-04)
Field: Materials Science — Polymers and Plastics

Exponential decay analysis: a flexible, robust, data-driven methodology for analyzing sorption kinetic data Sorption ; Microcrystalline cellulose ; Kinetics ; Exponential function ; Equilibrium moisture content ; Thermodynamics ; Moisture ; Kinetic energy ; Exponential decay ; Process engineering ; Computer science ; Biological system ; Cellulose ; Materials science ; Environmental science ; Chemistry ; Mathematics ; Physics ; Adsorption ; Physical chemistry ; Nuclear physics ; Engineering ; Composite material ; Organic chemistry ; Mathematical analysis Natural Fiber Reinforced Composites ; Wood Treatment and Properties ; Material Properties and Processing