Category: pyrazoles-derivatives

An article Copper(I) complex with BINAP and 3,5-dimethylpyrazole: synthesis and photoluminescent properties WOS:000496341100031 published article about CU(I) COMPLEXES; PHOTOPHYSICAL PROPERTIES; CRYSTAL; DESIGN in [Titov, Aleksei A.; Filippov, Oleg A.; Smol’yakov, Alexander F.; Shubina, Elena S.] Russian Acad Sci, AN Nesmeyanov Inst Organoelement Cpds, Moscow 119991, Russia; [Smol’yakov, Alexander F.] RUDN Univ, Peoples Friendship Univ Russia, Moscow 117198, Russia; [Smol’yakov, Alexander F.] GV Plekhanov Russian Univ Econ, Moscow 117997, Russia; [Averin, Alexey A.] Russian Acad Sci, AN Frumkin Inst Phys Chem & Electrochem, Moscow 199071, Russia in 2019.0, Cited 20.0. The Name is 3,5-Dimethyl-1H-pyrazole. Through research, I have a further understanding and discovery of 67-51-6. SDS of cas: 67-51-6

A reaction of [Cu(MeCN)(4)]BF4 with PzH (3,5-dimethyl-pyrazole) and BINAP [2,20-bis(diphenylphosphino)-1,10-bi-naphthyl] leads to the formation of mononuclear Cu-I complex [Cu(PzH)(BINAP)]BF4 containing the molecule of non-deprotonated pyrazole and one BINAP ligand with two phosphorus atoms chelating the metal. This complex exhibits a bright phosphorescence originating from the (3)(M+L)LCT state at room temperature. At 77 K, the emission is splitted into two components: (3)(M+L)LCT and (LC)-L-3 transitions.

SDS of cas: 67-51-6. Welcome to talk about 67-51-6, If you have any questions, you can contact Titov, AA; Filippov, OA; Smol’yakov, AF; Averin, AA; Shubina, ES or send Email.

Reference:
Pyrazole – Wikipedia,
,Pyrazoles – an overview | ScienceDirect Topics

Recently I am researching about C-H; BIOLOGICAL EVALUATION; PHOTOREDOX CATALYSIS; IN-VITRO; ALPHA-GLUCOSIDASE; PYRAZOLE; DERIVATIVES; POTENT; INHIBITORS; DESIGN, Saw an article supported by the Kuwait University [SC13/18]; [GS01/01]; [GS01/05]; [GS01/03]; [GS03/08]. Published in AMER CHEMICAL SOC in WASHINGTON ,Authors: Ibrahim, HM; Behbehani, H. The CAS is 86-92-0. Through research, I have a further understanding and discovery of 3-Methyl-1-p-tolyl-5-pyrazolone. Quality Control of 3-Methyl-1-p-tolyl-5-pyrazolone

A novel, metal catalyst-free, and efficient method has been developed for the synthesis of (pyrazol-4-ylidene) pyridine derivatives. The process involves dehydrogenative coupling of 1-amino-2-imino-pyridines with 1-aryl-5pyrazolone derivatives utilizing O-2 as the sole oxidant. The new method benefits from a high atom economy, efficiency, and substrate scope, as well as the simplicity of reaction and product purification procedures.

Bye, fridends, I hope you can learn more about C11H12N2O, If you have any questions, you can browse other blog as well. See you lster.. Quality Control of 3-Methyl-1-p-tolyl-5-pyrazolone

Reference:
Article; Zhang, Yong; Nie, Long-Jun; Luo, Liang; Mao, Jia-Xin; Liu, Jin-Xiang; Xu, Guo-Hai; Chen, Deliang; Luo, Hai-Qing; Tetrahedron; vol. 76; 7; (2020);,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Quality Control of 3-Methyl-1-p-tolyl-5-pyrazolone. In 2021 CHEM COMMUN published article about PHOTOPHYSICAL PROPERTIES; ACTIVATION; FUNCTIONALIZATION; MECHANISM in [Changmai, Sumi; Sultana, Sabera; Gogoi, Sanjib] North East Inst Sci & Technol, CSIR, Chem Sci & Technol Div, Appl Organ Chem, Jorhat 785006, Assam, India; [Changmai, Sumi; Sultana, Sabera; Gogoi, Sanjib] AcSIR, Ghaziabad 201002, India; [Sarma, Bipul] Tezpur Univ, Dept Chem Sci, Tezpur 784028, Assam, India in 2021, Cited 30. The Name is 3-Methyl-1-p-tolyl-5-pyrazolone. Through research, I have a further understanding and discovery of 86-92-0.

The Pd(ii)-catalyzed activation of Csp(2)-H bond and double alkyne annulation which proceeds via allylic isomerization is reported for the first time. This reaction of antipyrines with alkynes provides an efficient synthetic route for the biologically important spiro-cyclopentadiene pyrazolones. In the presence of Lawesson’s reagent, this Pd(ii)-catalyzed annulation reaction affords another spiro-cyclopentadiene pyrazolone which displays very good fluorescence properties.

Quality Control of 3-Methyl-1-p-tolyl-5-pyrazolone. Welcome to talk about 86-92-0, If you have any questions, you can contact Changmai, S; Sultana, S; Sarma, B; Gogoi, S or send Email.

Reference:
Article; Zhang, Yong; Nie, Long-Jun; Luo, Liang; Mao, Jia-Xin; Liu, Jin-Xiang; Xu, Guo-Hai; Chen, Deliang; Luo, Hai-Qing; Tetrahedron; vol. 76; 7; (2020);,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Authors Makhado, T; Das, B; Kriek, RJ; Vosloo, HCM; Swarts, AJ in ROYAL SOC CHEMISTRY published article about O BOND FORMATION; COPPER(II) COMPLEX; MOLECULAR CATALYSTS; IRIDIUM COMPLEXES; II COMPLEXES; NEUTRAL PH; LIGANDS; EFFICIENT; SYSTEMS; DESIGN in [Makhado, T.; Vosloo, H. C. M.; Swarts, A. J.] Northwest Univ, Res Focus Area Chem Resource Beneciat, Catalysis & Synth Res Grp, 11 Hoffman St, ZA-2531 Potchefstroom, South Africa; [Das, B.] Stockholm Univ, Arrhenius Lab, Dept Organ Chem, Svante Arrhenius Vag 16C, S-10691 Stockholm, Sweden; [Kriek, R. J.] Northwest Univ, Electrochem Energy & Environm Grp, Res Focus Area Chem Resource Beneficat, 11 Hoffman St, ZA-2531 Potchefstroom, South Africa; [Swarts, A. J.] Univ Witwatersrand, Sch Chem, Mol Sci Inst, ZA-2050 Johannesburg, South Africa in 2021.0, Cited 69.0. HPLC of Formula: C5H8N2. The Name is 3,5-Dimethyl-1H-pyrazole. Through research, I have a further understanding and discovery of 67-51-6

Herein a series of novel bis(pyrazol-1-ylmethyl)pyridine-ligated Cu(i) complexes, C1-C4, bearing different donating groups [[H(C1), Me(C2), t-Bu(C3), Ph(C4)])] on the pyrazole rings, were synthesized and investigated as pre-catalysts in chemical and electrocatalytic water oxidation reactions. Ligands, 2,6-bis((1H-pyrazol-1-yl)methyl)pyridine (L1), 2,6-bis((1H-pyrazol-1-yl)methyl)pyridine (L2), 2,6-bis((3,5-di-tert-butyl-1H-pyrazol-1-yl)methyl)pyridine (L3), and 2,6-bis((3,5-diphenyl-1H-pyrazol-1-yl)methyl)pyridine (L4) were reacted with Cu(MeCN)(4)PF6 to form complexes C1-C4 respectively. Cerium ammonium nitrate (CAN), sodium m-periodate, and sodium persulfate were investigated as chemical oxidants in chemical water oxidation. Complexes C1-C4 showed catalytic activity towards chemical water oxidation in the presence of CAN as the primary oxidant at 25 degrees C. Complex C2 was the most active with a turnover number (TON) of 4.6 and a turnover frequency (TOF) of 0.31 s(-1). The least active catalyst was complex C4, with a TON of 2.3 and a TOF of 0.0086 s(-1). This observed difference in catalytic activity between the complexes illustrated the key role that electronic effects play during catalysis. Other oxidants evaluated with C2 were sodium m-periodate (TON, 3.77; TOF 0.14 s(-1)) and sodium persulfate (TON, 4.02; TOF 0.044 s(-1)) however, CAN exhibited the greatest activity. Complexes C1-C4 were investigated in electrocatalytic water oxidation at a neutral pH of 6.5. Complex C2 was the most active in electrocatalytic water oxidation as well, exhibiting an overpotential of 674 mV and TOF of 9.77 s(-1) (at 1.7 V vs. NHE), which is better than most reported copper(ii) complexes. These Cu(i) complexes C1-C4 show potential as efficient chemical and electrocatalytic water oxidation catalysts, which can be achieved by fine-tuning the steric and electronic properties of the catalysts.

HPLC of Formula: C5H8N2. Welcome to talk about 67-51-6, If you have any questions, you can contact Makhado, T; Das, B; Kriek, RJ; Vosloo, HCM; Swarts, AJ or send Email.

Reference:
Pyrazole – Wikipedia,
,Pyrazoles – an overview | ScienceDirect Topics

Quality Control of 3-Methyl-1-p-tolyl-5-pyrazolone. Recently I am researching about N-HETEROCYCLIC CARBENE; ENANTIOSELECTIVE CONSTRUCTION; ORGANOCATALYSIS; PYRAZOLONES; ANNULATION; SCAFFOLDS; OXINDOLES; CATALYSIS, Saw an article supported by the NSFCNational Natural Science Foundation of China (NSFC) [21632003, 21871116, 21572087]; key program of Gansu province [17ZD2GC011]; 111 program from the MOE of P. R. China. Published in AMER CHEMICAL SOC in WASHINGTON ,Authors: Lu, H; Zhang, HX; Tan, CY; Liu, JY; Wei, H; Xu, PF. The CAS is 86-92-0. Through research, I have a further understanding and discovery of 3-Methyl-1-p-tolyl-5-pyrazolone

A sequential and general strategy has been successfully developed for the synthesis of spiropyrazolone scaffolds. This intriguing transformation of the asymmetric multicomponent catalysis process was realized with the combination of Michael addition/chlorination/nucleophilic substitution in a one-pot sequence, giving rise to a series of spiropyrazolones with fully substituted cyclopropanes and spiro-dihydrobenzofurans containing continuous stereogenic centers in good yields with excellent stereoselectivities.

Quality Control of 3-Methyl-1-p-tolyl-5-pyrazolone. Welcome to talk about 86-92-0, If you have any questions, you can contact Lu, H; Zhang, HX; Tan, CY; Liu, JY; Wei, H; Xu, PF or send Email.

Reference:
Article; Zhang, Yong; Nie, Long-Jun; Luo, Liang; Mao, Jia-Xin; Liu, Jin-Xiang; Xu, Guo-Hai; Chen, Deliang; Luo, Hai-Qing; Tetrahedron; vol. 76; 7; (2020);,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Recommanded Product: 1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carboxylic acid. Authors Rodrigues, T; Helene, O in AMER PHYSICAL SOC published article about in [Rodrigues, Tulio; Helene, Otaviano] Univ Sao Paulo, Phys Inst, Expt Phys Dept, POB 66318, BR-05315970 Sao Paulo, Brazil in 2020, Cited 43. The Name is 1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carboxylic acid. Through research, I have a further understanding and discovery of 83-10-3

This study provides a phenomenological method to describe the exponential growth, saturation, and decay of coronavirus disease 2019 (COVID-19) deaths and infections via a Monte Carlo approach. The calculations connect Gompertz-type trial distributions of infected people per day with the distribution of deaths adopting two gamma distributions to account for the elapsed time that encompass the incubation and symptom onset to death periods. The analyses include death data from the USA, Brazil, Mexico, the United Kingdom (UK), India, and Russia, which comprise the four countries with the highest number of deaths and the four countries with the highest number of confirmed cases, as of August 07, 2020, according to theWorld Health Organization webpage. The Gompertz functions were fitted to the data of weekly averaged confirmed deaths per day by mapping the chi(2) values. The uncertainties, variances, and covariances of the model parameters were calculated by propagation, taking into account the standard errors of the data for each epidemiological week. The fitted functions for the average deaths per day for the USA and India have an upward trend, with the former having a higher growth rate and quite huge uncertainties. For Mexico, the UK, and Russia, the fits are consistent with a downward-sloping pattern. For Brazil we found a subtle trend down but with significant uncertainties. The USA, UK, and India data showed first peaks with higher growth rates compared with the second ones (4.2, 2.2, and 3.5 times higher, respectively), demonstrating the benefits of nonpharmacological interventions of sanitary measures and social distance flattening the secondary peaks of the pandemic. For the case of the USA, however, a third peak seems quite plausible, most likely related with the recent relaxation policies. Brazil’s data are satisfactorily described by two highly overlapped Gompertz functions with similar growth rates, suggesting a two-step process for the pandemic spreading. For the cases of Mexico and Russia single peaks with smoother slopes fitted the data satisfactorily. The 95% confidence intervals for the total number of deaths (x10(3)) predicted by the model for August 31, 2020, are 160 to 220, 110 to 130, 59 to 62, 41.3 to 41.4, 54 to 63, and 16.0 to 16.7 for the USA, Brazil, Mexico, the UK, India, and Russia, respectively. Our estimates for the point prevalences of infections are compared with some preliminary data from serological studies and/or model calculations focused on the USA, Brazil, and UK scenarios. The point prevalences and 95% confidence intervals for August 1, 2020, were estimated to be 5.7 (3.9-7.5)%, 8.9 (7.4-10.3)%, 9.3 (8.3-10.3)%, 5.7 (4.5-6.9)%, 0.9 (0.8-1.0%), and 1.2 (1.0-1.3)% for the USA, Brazil, Mexico, the UK, India, and Russia, respectively. The method represents an effective few-parameter framework to estimate the line shape of the infection curves and the uncertainties of the relevant parameters based on the actual death data of a pandemic.

Recommanded Product: 1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carboxylic acid. Welcome to talk about 83-10-3, If you have any questions, you can contact Rodrigues, T; Helene, O or send Email.

Reference:
Patent; Shanghai Pharmaceutical Industry Institute; China Pharmaceutical Industry Zongyuan; Li Jianqi; Huang Daowei; Wang Wenya; Zhang Zhiguo; Jiang Ling; (45 pag.)CN107286140; (2017); A;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

An article One-Pot Asymmetric Synthesis of Spiropyrazolone-Linked Cyclopropanes and Benzofurans through a General Michael Addition/Chlorination/Nucleophilic Substitution Sequence WOS:000481979200038 published article about N-HETEROCYCLIC CARBENE; ENANTIOSELECTIVE CONSTRUCTION; ORGANOCATALYSIS; PYRAZOLONES; ANNULATION; SCAFFOLDS; OXINDOLES; CATALYSIS in [Lu, Hong; Zhang, Huan-Xin; Tan, Chang-Yin; Liu, Jin-Yu; Xu, Peng-Fei] Lanzhou Univ, Sch Chem & Chem Engn, State Key Lab Appl Organ Chem, Lanzhou 730000, Gansu, Peoples R China; [Lu, Hong; Wei, Hao] Northwest Univ, Coll Chem & Mat Sci, Natl Demonstrat Ctr Expt Chem Educ, Key Lab Synthet & Nat Funct Mol Chem,Minist Educ, Xian 710127, Shaanxi, Peoples R China in 2019, Cited 45. SDS of cas: 86-92-0. The Name is 3-Methyl-1-p-tolyl-5-pyrazolone. Through research, I have a further understanding and discovery of 86-92-0

A sequential and general strategy has been successfully developed for the synthesis of spiropyrazolone scaffolds. This intriguing transformation of the asymmetric multicomponent catalysis process was realized with the combination of Michael addition/chlorination/nucleophilic substitution in a one-pot sequence, giving rise to a series of spiropyrazolones with fully substituted cyclopropanes and spiro-dihydrobenzofurans containing continuous stereogenic centers in good yields with excellent stereoselectivities.

Bye, fridends, I hope you can learn more about C11H12N2O, If you have any questions, you can browse other blog as well. See you lster.. SDS of cas: 86-92-0

Reference:
Article; Zhang, Yong; Nie, Long-Jun; Luo, Liang; Mao, Jia-Xin; Liu, Jin-Xiang; Xu, Guo-Hai; Chen, Deliang; Luo, Hai-Qing; Tetrahedron; vol. 76; 7; (2020);,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

SDS of cas: 86-92-0. Recently I am researching about ALLYLIC DEAROMATIZATION REACTION; STEREOCONTROLLED CONSTRUCTION; MICHAEL ADDITION; ALKYLATION; ACID; PYRAZOLIN-5-ONES; PYRAZOL-5-ONES; ALCOHOLS; BEARING, Saw an article supported by the National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [21462042, 21262036]. Published in AMER CHEMICAL SOC in WASHINGTON ,Authors: Wu, GX; Xu, HH; Liu, ZR; Liu, YH; Yang, X; Zhang, XL; Huang, Y. The CAS is 86-92-0. Through research, I have a further understanding and discovery of 3-Methyl-1-p-tolyl-5-pyrazolone

In this letter, an efficient one-pot asymmetric sequential reaction is achieved by organo/transition metal relay catalysis in constructing two consecutive C-C bonds, which involves enantioselective amino squaramide catalytic Mannich-type addition of pyrazolones to isatin-derived ketimines and a subsequent palladium catalyzed diastereoselective allylic alkylation of pyrazolones with allylic acetates. An array of novel pyrazolone-aminooxindole-propylene structural motifs are obtained in a high level of yield and with excellent enantio- and diastereoselectivity (up to 95% yield, >20:1 dr, >99% ee). This methodology features the formation of vicinal quarternary carbon-stereocenters, and the second all-carbon tetrasubstituted stereogenic center is induced by joint action of the achiral palladium catalysis and the chiral environment generated from the Mannich step. Moreover, the usefulness of this methodology is highlighted by converting the allylic product into the carbonyl compound.

SDS of cas: 86-92-0. Welcome to talk about 86-92-0, If you have any questions, you can contact Wu, GX; Xu, HH; Liu, ZR; Liu, YH; Yang, X; Zhang, XL; Huang, Y or send Email.

Reference:
Article; Zhang, Yong; Nie, Long-Jun; Luo, Liang; Mao, Jia-Xin; Liu, Jin-Xiang; Xu, Guo-Hai; Chen, Deliang; Luo, Hai-Qing; Tetrahedron; vol. 76; 7; (2020);,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Authors Cuellar, E; Pastor, L; Garcia-Herbosa, G; Nganga, J; Angeles-Boza, AM; Diez-Varga, A; Torroba, T; Martin-Alvarez, JM; Miguel, D; Villafane, F in AMER CHEMICAL SOC published article about CARBON-DIOXIDE; ACID-BASE; ELECTROCATALYTIC REDUCTION; PYRAZOLYL COMPLEXES; MOLECULAR-STRUCTURE; METAL-COMPLEXES; RUTHENIUM(II); CATALYSTS; PH; FORMATE in [Cuellar, Elena; Pastor, Laura; Martin-Alvarez, Jose M.; Miguel, Daniel; Villafane, Fernando] Univ Valladolid, GIR MIOMeT IU Cinquima Quim Inorgan, Fac Ciencias, Campus Miguel Delibes, Valladolid 47011, Spain; [Garcia-Herbosa, Gabriel; Diez-Varga, Alberto; Torroba, Tomas] Univ Burgos, Fac Ciencias, Dept Quim, Burgos 09001, Spain; [Nganga, John; Angeles-Boza, Alfredo M.] Univ Connecticut, Dept Chem, Storrs, CT 06269 USA in 2021.0, Cited 78.0. SDS of cas: 67-51-6. The Name is 3,5-Dimethyl-1H-pyrazole. Through research, I have a further understanding and discovery of 67-51-6

New cis-(1,2-azole)-aquo bis(2,2′-bipyridyl)-ruthenium(II) (1,2-azole (az*H) = pzH (pyrazole), dmpzH (3,5-dimethylpyrazole), and indzH (indazole)) complexes are synthesized via chlorido abstraction from cis-[Ru(bipy)(2)Cl(az*H)]OTf. The latter are obtained from cis-[Ru(bipy)(2)Cl-2] after the subsequent coordination of the 1,2-azole. All the compounds are characterized by H-1, C-13, N-15 NMR spectroscopy as well as IR spectroscopy. Two chlorido complexes (pzH and indzH) and two aquo complexes (indzH and dmpzH) are also characterized by X-ray diffraction. Photophysical and electrochemical studies were carried out on all the complexes. The photophysical data support the phosphorescence of the complexes. The electrochemical behavior of all the complexes in an Ar atmosphere indicate that the oxidation processes assigned to Ru(II) -> Ru(III) occurs at higher potentials in the aquo complexes. The reduction processes under Ar lead to several waves, indicating that the complexes undergo successive electron-transfer reductions that are centered in the bipy ligands. The first electron reduction is reversible. The electrochemical behavior in CO2 media is consistent with CO2 electrocatalyzed reduction, where the values of the catalytic activity [i(cat)(CO2)/i(p)(Ar)] ranged from 2.9 to 10.8. Controlled potential electrolysis of the chlorido and aquo complexes affords CO and formic acid, with the latter as the major product after 2 h. Photocatalytic experiments in MeCN with [Ru(bipy)(3)]Cl-2 as the photosensitizer and TEOA as the electron donor, which were irradiated with >300 nm light for 24 h, led to CO and HCOOH as the main reduction products, achieving a combined turnover number (TONCO+HCOO-) as high as 107 for 2c after 24 h of irradiation.

SDS of cas: 67-51-6. Welcome to talk about 67-51-6, If you have any questions, you can contact Cuellar, E; Pastor, L; Garcia-Herbosa, G; Nganga, J; Angeles-Boza, AM; Diez-Varga, A; Torroba, T; Martin-Alvarez, JM; Miguel, D; Villafane, F or send Email.

Reference:
Pyrazole – Wikipedia,
,Pyrazoles – an overview | ScienceDirect Topics

HPLC of Formula: C5H8N2. I found the field of Chemistry very interesting. Saw the article VOLATILE PROFILE OF GREEN COFFEE BEANS FROM COFFEA ARABICA L. PLANTS GROWN AT DIFFERENT ALTITUDES IN ETHIOPIA published in 2019.0, Reprint Addresses Chandravanshi, BS (corresponding author), Addis Ababa Univ, Coll Nat Sci, Dept Chem, POB 1176, Addis Ababa, Ethiopia.. The CAS is 67-51-6. Through research, I have a further understanding and discovery of 3,5-Dimethyl-1H-pyrazole.

This study was aimed to identify volatile compounds of 31 green coffee bean samples and evalute their correlation with altitude of the coffee plants grown in two zones (Gedeo and Jimma) in Ethiopia. A total of 81 different compounds were detected. The contents of dominant volatile compounds in green coffee beans were in the range: trans-linalooloxide (3.24-19.13%), linalool (1.56-21.76%), 2-methoxy-4-vinylphenol (2.34-15.08%) and cis-linalooloxide (1.03-13.27%). In addition, benzene acetaldehyde (0.45-10.97%), 2-heptanol (0.67-8.49%), alpha-terpineol (0.64-6.52%), phenylethyl alcohol (0.44-4.98%) and furfural (0.92-5.3%) were the next dominant compounds. The volatile compounds identified in the green coffee beans are groups of alcohols, aldehydes, ketones, pyrazines, pyridines, and furans. The volatile compounds in green coffee beans showed either weak positive or weak negative correlation with the altitude of coffee plants indicating that variation in altitude of the coffee plants does not significantly influence the volative compounds of green coffee beans.

Bye, fridends, I hope you can learn more about C5H8N2, If you have any questions, you can browse other blog as well. See you lster.. HPLC of Formula: C5H8N2

Reference:
Pyrazole – Wikipedia,
,Pyrazoles – an overview | ScienceDirect Topics