Arylene–hexaynylene and –octaynylene macrocycles: extending the polyyne chains drives self-association by enhanced dispersion force

2021 ◽  
Author(s):  
Shin-ichiro Kato ◽  
Ryo Kumagai ◽  
Tsukasa Abe ◽  
Chisa Higuchi ◽  
Yoshihito Shiota ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Association Constants ◽  
Dispersion Force ◽  
Self Association ◽  
First Time

We synthesized arylene–alkynylene macrocycles containing hexayne and octayne, which enables quantitative analysis of self-association constants depending on the length of the polyyne chains for the first time.

scholarly journals Determination of Flavonoids Compounds of Three Species and Different Harvesting Periods in Crataegi folium Based on LC-MS/MS

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1602
Author(s):  
Ya-Ping Guo ◽  
Hong Yang ◽  
Ya-Li Wang ◽  
Xiao-Xiang Chen ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Qualitative Analysis ◽  
Quantitative Method ◽  
Total Content ◽  
Qualitative And Quantitative Analysis ◽  
Pharmacological Activities ◽  
Time Saving ◽  
Qualitative And Quantitative ◽  
First Time

Crataegi folium have been used as medicinal and food materials worldwide due to its pharmacological activities. Although the leaves of Crataegus songorica (CS), Crataegus altaica (CA) and Crataegus kansuensis (CK) have rich resources in Xinjiang, China, they can not provide insights into edible and medicinal aspects. Few reports are available on the qualitative and quantitative analysis of flavonoids compounds of their leaves. Therefore, it is necessary to develop efficient methods to determine qualitative and quantitative flavonoids compounds in leaves of CS, CA and CK. In the study, 28 unique compounds were identified in CS versus CK by qualitative analysis. The validated quantitative method was employed to determine the content of eight flavonoids of the leaves of CS, CA and CK within 6 min. The total content of eight flavonoids was 7.8–15.1 mg/g, 0.1–9.1 mg/g and 4.8–10.7 mg/g in the leaves of CS, CA and CK respectively. Besides, the best harvesting periods of the three species were from 17th to 26th September for CS, from 30th September to 15th October for CA and CK. The validated and time-saving method was successfully implemented for the analysis of the content of eight flavonoids compounds in CS, CA and CK for the first time.

scholarly journals Negligible Voltage Hysteresis with Strong Anionic Redox in Conventional Battery Electrode

2020 ◽  
Author(s):  
Kehua Dai ◽  
Jing Mao ◽  
Zengqing Zhuo ◽  
Guo Ai ◽  
Wenfeng Mao ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Redox Reactions ◽  
Coulombic Efficiency ◽  
Redox Systems ◽  
Redox Mechanism ◽  
Practical Applications ◽  
Battery Electrode ◽  
Voltage Hysteresis ◽  
First Time ◽  
Initial Coulombic Efficiency

<div>Lattice oxygen redox reactions (ORR) offers opportunities for developing highcapacity batteries, however, suffers the notoriously high voltage hysteresis and low initial coulombic efficiency, which hinder its practical applications. Particularly, ORR was widely considered inherent to these kinetic issues. In this paper, unambiguous evidence of strong and reversible ORR is found in Na<sub>2/3</sub>Ni<sub>1/3</sub>Mn<sub>2/3</sub>O<sub>2</sub>, which displays negligible voltage hysteresis (0.1 V) and high initial coulombic efficiency with a highly stable electrochemical profile. Our independent and quantitative analysis of all the Ni, Mn and O states consistently interpret the redox mechanism of Na<sub>2/3</sub>Ni<sub>1/3</sub>Mn<sub>2/3</sub>O<sub>2</sub>, which reveals, for the first time, a conventional 3d transition-metal ORR system with facile kinetics and highly stable electrochemical profile that previously found only in cationic redox systems.</div>

A Brief History of Time (to Issuance)

2021 ◽  
pp. 139-165
Author(s):  
Andrew Rudalevige
Keyword(s):  
Quantitative Analysis ◽  
Collective Action ◽  
Case Studies ◽  
Management Process ◽  
Executive Order ◽  
Order Management ◽  
Collective Action Problems ◽  
History Of ◽  
First Time ◽  
Huge Variation

This chapter examines to another aspect of executive order management. It turns out that the average executive order takes some seventy-five days to move from draft proposal to the Federal Register, with huge variation around that figure. What affects that timing? What makes an executive order take longer to issue? What characteristics of orders and agencies, of interagency interaction and requirements of the management process itself, are associated with delay? Quantitative analysis, elaborated by case studies, helps us explore these questions for the first time as the duration of the formulation process is tested as a proxy for executive collective action problems.

scholarly journals Investigation of 1-Methylcytosine as a Ligand in Gold(III) Complexes: Synthesis and Protein Interactions

Inorganics ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
James Beaton ◽  
Nicholas Farrell
Keyword(s):  
Fluorescence Quenching ◽  
Zinc Finger ◽  
Protein Interactions ◽  
Nucleocapsid Protein ◽  
1H Nmr Spectroscopy ◽  
Ionization Mass ◽  
Target Interaction ◽  
Self Association ◽  
A Charge ◽  
First Time

The HIV nucleocapsid protein NCp7 was previously shown to play a number of roles in the viral life cycle and was previously identified as a potential target for small molecule intervention. In this work, the synthesis of the previously unreported complexes [Au(dien)(1MeCyt)]3+, [Au(N-Medien)(1MeCyt)]3+, and [Au(dien)(Cyt)]3+ is detailed, and the interactions of these complexes with the models for NCp7 are described. The affinity for these complexes with the target interaction site, the “essential” tryptophan of the C-terminal zinc finger motif of NCp7, was investigated through the use of a fluorescence quenching assay and by 1H-NMR spectroscopy. The association of [Au(dien)(1MeCyt)]3+ as determined through fluorescence quenching is intermediate between the previously reported DMAP and 9-EtGua analogs, while the associations of [Au(N-Medien)(1MeCyt)]3+ and [Au(dien)(Cyt)]3+ are lower than the previously reported complexes. Additionally, NMR investigation shows that the self-association of relevant compounds is negligible. The specifics of the interaction with the C-terminal zinc finger were investigated by circular dichroism spectroscopy and electrospray-ionization mass spectrometry. The interaction is complete nearly immediately upon mixing, and the formation of AuxFn+ (x = 1, 2, or 4; F = apopeptide) concomitant with the loss of all ligands is observed. Additionally, oxidized dimerized peptide was observed for the first time as a product, indicating a reaction via a charge transfer mechanism.

scholarly journals Quantitative Analysis of Protein Self‐Association by Sedimentation Velocity

2020 ◽  
Vol 101 (1) ◽  
Author(s):  
Huaying Zhao ◽  
Wenqi Li ◽  
Wendan Chu ◽  
Mary Bollard ◽  
Regina Adão ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Sedimentation Velocity ◽  
Self Association

Vertical charge transport through transition metal dichalcogenides – a quantitative analysis

Nanoscale ◽  
2017 ◽  
Vol 9 (48) ◽  
pp. 19108-19113 ◽  
Author(s):  
Yuqi Zhu ◽  
Ruiping Zhou ◽  
Feng Zhang ◽  
Joerg Appenzeller
Keyword(s):  
Quantitative Analysis ◽  
Transition Metal ◽  
Charge Transport ◽  
Effective Mass ◽  
Transition Metal Dichalcogenides ◽  
Vertical Direction ◽  
Metal Dichalcogenides ◽  
First Time

Effective mass in the vertical direction of MoS2 and WSe2 has been extracted for the first time.

scholarly journals Simultaneous Quantification of Diarylheptanoids and Phenolic Compounds in Juglans mandshurica Maxim. by UPLC–TQ-MS

Separations ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 132
Author(s):  
Hong Yang ◽  
Li-Bo Wang ◽  
Ya-Ping Guo ◽  
Ya-Li Wang ◽  
Xiao-Xiang Chen ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Phenolic Compounds ◽  
Juglans Regia ◽  
Folk Medicine ◽  
Total Content ◽  
Antitumor Activities ◽  
Juglans Mandshurica ◽  
Intrinsic Quality ◽  
First Time

The immature epicarps of Juglans mandshurica and Juglans regia have been used as folk medicine for the treatment of cancer in China. Other parts of the J.mandshurica plant, including leaves, branches, barks, and stems, have reported antitumor activities. We previously found that various diarylheptanoids and phenolic compounds isolated from J. mandshurica epicarps show significant antitumor activities. However, there are no reports of quantitative analysis of diarylheptanoids and phenolic compounds of J. mandshurica. In this study, a validated quantitative method, based on ultraperformance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry, was employed to determine the contents of eight diarylheptanoids and seven phenolic compounds in the epicarps of J. mandshurica during different growth periods, in different parts of the plant, and in the epicarps of two Juglans species. The most successful J. mandshurica epicarp harvesting time fell between Day 12 and Day 27. The leaves of J. mandshurica showed potential for medical use as they had the highest content of the 15 compounds (3.399 ± 0.013 mg/g). We showed for the first time that the total content of diarylheptanoids in J. mandshurica is higher than that in J. regia, though, conversely, J. regia has higher contents of phenolic compounds. The method developed in this study is practical and simple and can be applied for quantitative analysis for evaluating the intrinsic quality of J. mandshurica.

scholarly journals Composition of Seed Essential Oils of Rhododendron tomentosum

2012 ◽  
Vol 7 (2) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Asta Judzentiene ◽  
Rita Butkiene ◽  
Jurga Budiene ◽  
Félix Tomi ◽  
Joseph Casanova
Keyword(s):  
Quantitative Analysis ◽  
Chemical Composition ◽  
Nmr Spectroscopy ◽  
Essential Oil ◽  
Essential Oils ◽  
Thermal Isomerization ◽  
Total Oil ◽  
First Time ◽  
Rhododendron Tomentosum ◽  
C Nmr

For the first time, the chemical composition of the seed essential oil of Rhododendron tomentosum was determined. Forty-seven compounds were identified, comprising 91.7% of the total oil. Palustrol (38.3%) and ledol (27.0%) were the predominant constituents. Some constituents, such as β-pinene oxide, iso-menthyl acetate, nerolidyl acetate, cadalene and guaiazulene were characteristic only for the seeds and were identified for the first time in Rh. tomentosum oils. For comparison purposes, the essential oil isolated from the shoots of the same plant were analyzed [GC(FID) in combination with RIs, GC-MS and 13C NMR]. More than a half of the oil was comprised of ledol (36.5%) and palustrol (21.0%). Quantitative analysis of ascaridol, a heat-sensitive compound, was carried out by 13C NMR spectroscopy. Indeed, ascaridol undergoes partial thermal isomerization to iso-ascaridol during GC analyses.

scholarly journals Flavonoids from Lonchocarpus muehlbergianus

2004 ◽  
Vol 76 (4) ◽  
pp. 651-661 ◽  
Author(s):  
Aderbal F. Magalhães ◽  
Ana M.G.A. Tozzi ◽  
Eva G. Magalhães ◽  
Ivani S. Blanco ◽  
Maria-Del-Pilar C. Soriano
Keyword(s):  
Quantitative Analysis ◽  
Spectral Data ◽  
13C Nmr ◽  
2D Nmr ◽  
Reversed Phase ◽  
Light Petroleum ◽  
Natural Occurrence ◽  
Reversed Phase Hplc ◽  
First Time

The light petroleum extract from the roots of Lonchocarpus muehlbergianus Hassl contained nine flavonoids, including six new ones. These are 2,4-cis-2,4,5,8-tetramethoxy-(2´´,3´´:6,7)-furanoflavan; 2,4-cis-4-hydroxy-2,5,8-trimethoxy-(2´´,3´´:6,7)-furanoflavan; 2,4-cis-2-prenyloxy-4,5,8-trimethoxy-(2´´,3´´:6,7)-fu-ranoflavan; 2,4-cis-2-prenyloxy-4-hydroxy-5,8-dimethoxy-(2´´,3´´:6,7)-furanoflavan; 2',5',6'-trimethoxy-9-(1,1-dimethylallyoxy)-[2´´,3´´:3´,4´]-furanochalcone; 5,6-dimethoxy-(2´´,3´´:7,8)-furanoflavone, identi-fied by analysis of their spectral data (UV, IR, ¹H and 13C NMR, 2D-NMR, NOE and MS). The natural occurrence of 2,4-dioxygenated flavan derivatives is being reported for the first time. Quantitative analysis of the petrol extract, by using reversed-phase HPLC, showed that the most abundant flavonoid in the extract is 2,4-cis-2,4,5,8- tetramethoxy-(2´´,3´´:6,7)-furanoflavan.

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