Crystallographic and spectroscopic characterization of a mixed actinide–lanthanide carbide cluster stabilized inside an Ih(7)-C80 fullerene cage

2020 ◽  
Vol 56 (27) ◽  
pp. 3867-3870 ◽  
Author(s):  
Xiaomeng Li ◽  
Yang-Rong Yao ◽  
Wei Yang ◽  
Jiaxin Zhuang ◽  
Luis Echegoyen ◽  
...  
Keyword(s):  
Spectroscopic Characterization ◽  
Fullerene Cage ◽  
Spectroscopic Analyses ◽  
Carbide Cluster ◽  
First Time

For the first time, crystallographic and spectroscopic analyses identified that a mixed actinide–lanthanide carbide cluster Sc2UC, with a very short UC bond, is stabilized inside an Ih(7)-C80 cage.

Spectroscopic characterization of C7H3+ and C7H3˙: electronic absorption and fluorescence in 6 K neon matrices

2014 ◽  
Vol 16 (15) ◽  
pp. 7023-7030 ◽  
Author(s):  
Arghya Chakraborty ◽  
Jan Fulara ◽  
Rainer Dietsche ◽  
John P. Maier
Keyword(s):  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Spectroscopic Characterization ◽  
First Time

Electronic absorption spectra of mass-selected C7H3+ and C7H3˙ isomers in a neon matrix have been identified for the first time.

scholarly journals Biomacromolecules in recent phosphate-shelled brachiopods: identification and characterization of chitin matrix

2021 ◽  
Author(s):  
Oluwatoosin B. A. Agbaje ◽  
Glenn A. Brock ◽  
Zhifei Zhang ◽  
Kingsley C. Duru ◽  
Yue Liang ◽  
...  
Keyword(s):  
Organic Matrix ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Shallow Marine ◽  
The Core ◽  
Spectroscopic Analyses ◽  
Living Organisms ◽  
First Time ◽  
Identification And Characterization

Abstract Phosphate-shelled brachiopods differ in filter-feeding lifestyle, with Lingula anatina an active infaunal burrower, and Discinisca tenuis a shallow marine epibenthic animal. The shells of these animals are built of organophosphatic constituents, the organic fibres/sheets reinforced with calcium phosphate to provide a sophisticated ultrastructural robustness. This investigation examined the nature of the organic fibres in order to improve understanding of how living organisms produce hierarchically structured biomaterials. Unlike powdered samples commonly used in previous studies, organic fibres were isolated for the first time and the shell fractions were purified, in order to study the content and nature of the biopolymer fibres. Biochemical methods including Calcofluor staining revealed a chitin matrix. Ultrastructural analysis, thermal gravimetric analysis, and spectroscopic analyses show that the core polysaccharide framework is composed of layers of β-chitin sheets and/or fibrils that are coated with a fibrous organic matrix. There is more chitin matrix in the L. anatina shells (26.6 wt.%) compared to the D. tenuis shells (12.9 wt.%). Taken together, the data show that the chitin matrix contributes to increased skeletal strength, making L. anatina highly adapted for life as an active burrower. In comparison, D. tenuis contains less chitin and lives as attached epibenthos in a shallow marine environment. Graphical abstract First spectroscopic evidence of β-chitin sheets in recent organophosphatic brachiopods

Spectroscopic Characterization of the Selenium-Rich Heterocycles Se5S, Se7S, and 1,5-Se6S2

1991 ◽  
Vol 46 (12) ◽  
pp. 1674-1678 ◽  
Author(s):  
Ralf Steudel ◽  
Maria Papavassiliou ◽  
Frank Baumgart
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Spectroscopic Characterization ◽  
Reversed Phase ◽  
Nucleophilic Attack ◽  
Crystal Data ◽  
Reversed Phase Hplc ◽  
Cyclic Molecules ◽  
First Time

Se5S in CS2 solution at 20°C spontaneously decomposes to give a mixture of 8 selenium-rich cyclic molecules which have been identified by reversed-phase HPLC and 77Se NMR spectroscopy as Se6, Se7, Se8, Se6S, Se7S, 1,2-Se6S2, 1,5-Se6S2, and 1,4-Se4S2. NMR spectra of Se5S, Se7S, and 1,5-Se6S2 have been measured for the first time; Raman spectra of solid Se5S and Se7S as well as crystal data of Se7S are reported in addition. A mechanism based on nucleophilic attack on Se5S is proposed for the formation of the products.

scholarly journals Crystal structure and Hirshfeld surface analysis of lapachol acetate 80 years after its first synthesis

2019 ◽  
Vol 75 (9) ◽  
pp. 1362-1366
Author(s):  
Miguel A. Martínez-Cabrera ◽  
Mario A. Macías ◽  
Francisco Ferreira ◽  
Enrique Pandolfi ◽  
Javier Barúa ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Surface Analysis ◽  
Molecular Conformation ◽  
Spectroscopic Characterization ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
High Yield ◽  
First Time

Lapachol acetate [systematic name: 3-(3-methylbut-2-enyl)-1,4-dioxonaphthalen-2-yl acetate], C17H16O4, was prepared using a modified high-yield procedure and its crystal structure is reported for the first time 80 years after its first synthesis. The full spectroscopic characterization of the molecule is reported. The molecular conformation shows little difference with other lapachol derivatives and lapachol itself. The packing is directed by intermolecular π–π and C—H...O interactions, as described by Hirshfeld surface analysis. The former interactions make the largest contributions to the total packing energy in a ratio of 2:1 with respect to the latter.

Investigation of Antiplasmodial Effects of Terpenoid Compounds Isolated from Myrrh

Planta Medica ◽  
2020 ◽  
Vol 86 (09) ◽  
pp. 643-654 ◽  
Author(s):  
Hippolyt L. Greve ◽  
Marcel Kaiser ◽  
Thomas J. Schmidt
Keyword(s):  
Plasmodium Falciparum ◽  
In Vitro Activity ◽  
Isolation And Characterization ◽  
Spectroscopic Analyses ◽  
Ic50 Value ◽  
Ic50 Values ◽  
O 18 ◽  
First Time

AbstractAs part of our ongoing search for antiprotozoal natural products from plants, we examined different resins from the Burseraceae family. The dichloromethane extract obtained from myrrh, the oleo-gum-resin of Commiphora species, showed promising in vitro activity against Plasmodium falciparum with an IC50 value of 1 µg/mL. Bioactivity-guided fractionation led to the isolation and characterization of 18 sesquiterpenoids, namely, β-elemene (1), elemyl acetate (2), curzerenone (3), 8-hydroxyisogermafurenolide (4), 2-methoxyisogermafurenolide (5), 8-epi-2-methoxyisogermafurenolide (6), furanodienone (7), 1(10)Z,4Z-furanodien-6-one (8), rel-2R-methyl-5S-acetoxy-4R-furanogermacr-1(10)Z-en-6-one (9), (1(10)E)-2-methoxy-8,12-epoxygermacra-1(10),7,11-trien-6-one (10), 2R-methoxyfuranodiene (11), 2-acetyloxyglechomanolide (12), 8-epi-2-acetyloxyglechomanolide (13), (1R,2R,4S)-1,2-epoxyfuranogermacr-10(15)-en-6-one (14), hydroxylindestrenolide (15), isohydroxylindestrenolide (16), myrrhone (17), and myrrhterpenoid O (18). Moreover, nine (nor-)triterpenoids were isolated: mansumbinol (19), mansumbinol epoxide (20), mansumbinone (21), mansumbin-13(17)-en-3,16-dione (22), 3,4-seco-mansumbinoic acid (23), rel-20S-hydroxy-dammar-24-en-3,16-dione (24), rel-(16S,20S)-dihydroxydammar-24-en-3-one (25), cycloart-24-en-1α,2α,3β-triol (26), and 3β-isovaleroyloxycycloart-24-en-1α,2α-diol (27). All compounds were identified by MS and NMR spectroscopic analyses. To the best of our knowledge, compounds 5, 6, 12, 13, 16, 18, and 20 are reported for the first time. All isolated compounds were tested in vitro for activity against P. falciparum and cytotoxicity. The sesquiterpene 7 and the triterpene 25 were the most active compounds found in this study with IC50 values of 7.4 and 2.8 µM, respectively.

scholarly journals Spatially resolved spectroscopy of close massive visual binaries with HST/STIS

2020 ◽  
Vol 636 ◽  
pp. A28 ◽  
Author(s):  
J. Maíz Apellániz ◽  
R. H. Barbá
Keyword(s):  
Spectroscopic Characterization ◽  
Space Telescope ◽  
Multiple Systems ◽  
Spatially Resolved ◽  
Profile Fitting ◽  
Spatially Resolved Spectroscopy ◽  
First Time ◽  
Magnitude Difference ◽  
Visual Binaries

Context. The spectroscopic characterization of many O-type stars is hampered by a nearby companion. Aims. We want to obtain spatially resolved spectroscopy of close O-type visual binaries to derive their spectral types. Methods. We used the Space Telescope Imaging Spectrograph (STIS) of the Hubble Space Telescope (HST) to obtain long-slit blue-violet spectroscopy of eight Galactic O-type stars with nearby visual companions and used spatial-profile fitting to extract the separate spectra. We also used the ground-based Galactic O-Star Spectroscopic Survey to study more distant visual components. Results. We spatially resolve seven of the eight systems, present spectra for their components, and obtain their spectral types. Those seven multiple systems are ι Ori Aa,Ab,B; 15 Mon Aa,Ab,C; τ CMa Aa,Ab,B,C,D,E; HD 206 267 Aa,Ab,C,D; HD 193 443 A,B; HD 16 429 Aa,Ab; and IU Aur A,B. This is the first time that spatially resolved spectroscopy of the close visual binaries of those systems is obtained. We establish the applicability of the technique as a function of the separation and magnitude difference of the binary.

An irresolute linker: separation, and structural and spectroscopic characterization of the two linkage isomers of a Ru(ii)-(2-(2′-pyridyl)pyrimidine-4-carboxylic acid) complex

2014 ◽  
Vol 43 (32) ◽  
pp. 12160-12163 ◽  
Author(s):  
E. Iengo ◽  
N. Demitri ◽  
G. Balducci ◽  
E. Alessio
Keyword(s):  
Solid State ◽  
Carboxylic Acid ◽  
Spectroscopic Characterization ◽  
Acid Complex ◽  
Linkage Isomers ◽  
First Time

For the first time the two linkage isomers of a Ru(ii) complex with 2-(2′-pyridyl)pyrimidine-4-carboxylic acid (cppH) have been fully characterized individually, both in solution and in the solid state.

scholarly journals Salicylate Biosynthesis: Overexpression, Purification, and Characterization of Irp9, a Bifunctional Salicylate Synthase from Yersinia enterocolitica

2005 ◽  
Vol 187 (15) ◽  
pp. 5061-5066 ◽  
Author(s):  
Olivier Kerbarh ◽  
Alessio Ciulli ◽  
Nigel I. Howard ◽  
Chris Abell
Keyword(s):  
Yersinia Enterocolitica ◽  
Enzyme Assays ◽  
Purification And Characterization ◽  
Reverse Phase ◽  
H Nmr ◽  
Spectroscopic Analyses ◽  
Single Protein ◽  
Salicylate Synthase ◽  
First Time

ABSTRACT In some bacteria, salicylate is synthesized using the enzymes isochorismate synthase and isochorismate pyruvate lyase. In contrast, gene inactivation and complementation experiments with Yersinia enterocolitica suggest the synthesis of salicylate in the biosynthesis of the siderophore yersiniabactin involves a single protein, Irp9, which converts chorismate directly into salicylate. In the present study, Irp9 was for the first time heterologously expressed in Escherichia coli as a hexahistidine fusion protein, purified to near homogeneity, and characterized biochemically. The recombinant protein was found to be a dimer, each subunit of which has a molecular mass of 50 kDa. Enzyme assays, reverse-phase high-pressure liquid chromatography and 1H nuclear magnetic resonance (NMR) spectroscopic analyses confirmed that Irp9 is a salicylate synthase and converts chorismate to salicylate with a Km for chorismate of 4.2 μM and a k cat of 8 min−1. The reaction was shown to proceed through the intermediate isochorismate, which was detected directly using 1H NMR spectroscopy.

TBE in Sweden

2020 ◽  
Keyword(s):  
Genetic Characterization ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Second Phase ◽  
Serum Samples ◽  
Tick Borne Encephalitis ◽  
Specific Immunoglobulin ◽  
Tick Borne Encephalitis Virus ◽  
First Time

Tick-borne encephalitis virus (TBEV) was isolated for the first time in Sweden in 1958 (from ticks and from 1 tick-borne encephalitis [TBE] patient).1 In 2003, Haglund and colleagues reported the isolation and antigenic and genetic characterization of 14 TBEV strains from Swedish patients (samples collected 1991–1994).2 The first serum sample, from which TBEV was isolated, was obtained 2–10 days after onset of disease and found to be negative for anti-TBEV immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA), whereas TBEV-specific IgM (and TBEV-specific immunoglobulin G/cerebrospinal fluid [IgG/CSF] activity) was demonstrated in later serum samples taken during the second phase of the disease.

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