105 research outputs found
Closed Aromatic Tubes-Capsularenes
In this study, we describe a synthetic method for incorporating arenes into closed tubes that we name capsularenes. First, we prepared vase-shaped molecular baskets 4–7. The baskets comprise a benzene base fused to three bicycle[2.2.1]heptane rings that extend into phthalimide (4), naphthalimide (6), and anthraceneimide sides (7), each carrying a dimethoxyethane acetal group. In the presence of catalytic trifluoroacetic acid (TFA), the acetals at top of 4, 6 and 7 change into aliphatic aldehydes followed by their intramolecular cyclization into 1,3,5-trioxane (1H NMR spectroscopy). Such ring closure is nearly a quantitative process that furnishes differently sized capsularenes 1 (0.7×0.9 nm), 8 (0.7×1.1 nm;) and 9 (0.7×1.4 nm;) characterized by X-Ray crystallography, microcrystal electron diffraction, UV/Vis, fluorescence, cyclic voltammetry, and thermogravimetry. With exceptional rigidity, unique topology, great thermal stability, and perhaps tuneable optoelectronic characteristics, capsularenes hold promise for the construction of novel organic electronic devices
Ultra-broad near-infrared photoluminescence from crystalline (K-crypt)2Bi2 containing [Bi2]2- dimers
For the first time, we report that a single crystal of (K-crypt)2Bi2
containing [Bi2]2+ displays ultra-broad near-infrared photoluminescence (PL)
peaking at around 1190 nm and having a full width at the half maximum of 212
nm, stemming from the inherent electronic transitions of [Bi2]2+.The results
not only add to the number of charged Bi species with luminescence, but also
deepen the understanding of Bi-related near-infrared emission behavior and lead
to the reconsideration of the fundamentally important issue of Bi-related PL
mechanisms in some material systems such as bulk glasses, fibers, and
conventional optical crystals
Mitochondrial function is involved in regulation of cholesterol efflux to apolipoprotein (apo)A-I from murine RAW 264.7 macrophages
<p>Abstract</p> <p>Background</p> <p>Mitochondrial DNA damage, increased production of reactive oxygen species and progressive respiratory chain dysfunction, together with increased deposition of cholesterol and cholesteryl esters, are hallmarks of atherosclerosis. This study investigated the role of mitochondrial function in regulation of macrophage cholesterol efflux to apolipoprotein A-I, by the addition of established pharmacological modulators of mitochondrial function.</p> <p>Methods</p> <p>Murine RAW 264.7 macrophages were treated with a range of concentrations of resveratrol, antimycin, dinitrophenol, nigericin and oligomycin, and changes in viability, cytotoxicity, membrane potential and ATP, compared with efflux of [<sup>3</sup>H]cholesterol to apolipoprotein (apo) A-I. The effect of oligomycin treatment on expression of genes implicated in macrophage cholesterol homeostasis were determined by quantitative polymerase chain reaction, and immunoblotting, relative to the housekeeping enzyme, <it>Gapdh</it>, and combined with studies of this molecule on cholesterol esterification, <it>de novo</it> lipid biosynthesis, and induction of apoptosis. Significant differences were determined using analysis of variance, and Dunnett’s or Bonferroni post <it>t</it>-tests, as appropriate.</p> <p>Results</p> <p>The positive control, resveratrol (24 h), significantly enhanced cholesterol efflux to apoA-I at concentrations ≥30 μM. By contrast, cholesterol efflux to apoA-I was significantly inhibited by nigericin (45%; <it>p</it><0.01) and oligomycin (55%; <it>p</it><0.01), under conditions (10 μM, 3 h) which did not induce cellular toxicity or deplete total cellular ATP content. Levels of ATP binding cassette transporter A1 (ABCA1) protein were repressed by oligomycin under optimal efflux conditions, despite paradoxical increases in <it>Abca1</it> mRNA. Oligomycin treatment did not affect cholesterol biosynthesis, but significantly inhibited cholesterol esterification following exposure to acetylated LDL, and induced apoptosis at ≥30 μM. Finally, oligomycin induced the expression of genes implicated in both cholesterol efflux (<it>Abca1</it>, <it>Abcg4</it>, <it>Stard1</it>) and cholesterol biosynthesis (<it>Hmgr</it>, <it>Mvk</it>, <it>Scap</it>, <it>Srebf2</it>), indicating profound dysregulation of cholesterol homeostasis.</p> <p>Conclusions</p> <p>Acute loss of mitochondrial function, and in particular Δψ<sub>m</sub>, reduces cholesterol efflux to apoA-I and dysregulates macrophage cholesterol homeostasis mechanisms. Bioavailable antioxidants, targeted to mitochondria and capable of sustaining effective mitochondrial function, may therefore prove effective in maintenance of arterial health.</p
Pd-Catalyzed Enantioselective Hydroalkoxylation of Alkoxyallenes with Phenol for Construction of Acyclic O
Resistance of Aegilops, maize and wheat genotypes to Pseudomonas syringae pathovars atrofaciens and syringae
Resistance of Aegilops, maize and wheat genotypes to Pseudomonas syringae pathovars atrofaciens and syringae
The resistance of cereal genotypes to the artificial inoculation of Pseudomonas syringae pathovars atrofaciens (PSA) and syringae (PSS) at third leaf growth stage of development was investigated. The methods of pricking and injecting were used. The injection method produced symptoms similar to natural infection, at level of inoculum at least 107 cfu/ml. At this stage of cereal growth there was a high level of resistance to PSA and PSS. None of the Aegilops species showed the symptoms of susceptible genotypes. Only one Triticum genotype was susceptible to strains V28 and Y4895 of PSA and PSS, respectively, at the highest level of inoculum. The leaves of all Zea mays genotypes were susceptible to PSS A106 at 109 cfu/ml.Résistance des génotypes d'Aegilops, de maïs et de blé à Pseudomonas syringae pathovars (pvs) atrofaciens (PSA) et syringae (PSS). La résistance au PSA et au PSS des génotypes des céréales a été étudiée après inoculation par les méthodes de scarification et d'injection. La dernière méthode permet d'obtenir des symptômes de maladie similaires à ceux obtenus dans la nature au niveau d'inoculum de 107 cfu/ml et plus. Les plantules au stade 3 feuilles ont montré un niveau élevé de résistance à PSA et PSS. Aucune espèce d'Aegilops n'a montré d'infection comme chez les génotypes sensibles. Un seul génotype de Triticum est sensible au plus haut niveau d'inoculation par PSA V28 et PSS Y4895. Les feuilles de tous les génotypes de maïs sont sensibles au PSS A 106 à la concentration de 109 cfu/ml
Hydrogen-Bonded Inclusion Compounds with Reversed Polarity: Anionic Metal-Complexes and Cationic Organic Linkers
Synthesized and structurally characterized is a new series
of soft-host
frameworks assembled by charge-assisted hydrogen bonds between an
anionic metal complex (MC) and cationic organic linkers (OL), specifically
[Co(en)(ox)<sub>2</sub>]<sup>−</sup> and diprotonated 4,4′-bipyridinium
(H<sub>2</sub>bpy) or 1,2-bis(4-pyridinium)ethylene (H<sub>2</sub>bpye). While frameworks built of cationic complexes and anionic organic
linkers are already well-known, the seven new compounds described
here represent the first series of frameworks with reversed polarity,
that is, made of anionic complexes and cationic organic linkers. The
compounds have a general formula [OL][MC]<sub>2</sub>·<i>n</i>(<i>guest</i>), where the guest molecules 4,4′-biphenol
(<i>bp</i>), 4-methoxyphenol (<i>mp</i>), 1,4-dimethoxybenzene
(<i>dmb</i>), 1,6-dimethoxynaphtalene (<i>dmn</i>), and 4-nitroanisole (<i>na</i>). Structurally the compounds
can be described as pillared-layer frameworks with layers constructed
of MC anions and linked together by hydrogen-bonded cationic OL pillars.
The guest molecules occupy the galleries between the pillars while
their steric, electronic, and π–π and hydrogen-bonding
capabilities influence the overall structure of the soft frameworks
Hydrogen-Bonded Inclusion Compounds with Reversed Polarity: Anionic Metal-Complexes and Cationic Organic Linkers
Synthesized and structurally characterized is a new series
of soft-host
frameworks assembled by charge-assisted hydrogen bonds between an
anionic metal complex (MC) and cationic organic linkers (OL), specifically
[Co(en)(ox)<sub>2</sub>]<sup>−</sup> and diprotonated 4,4′-bipyridinium
(H<sub>2</sub>bpy) or 1,2-bis(4-pyridinium)ethylene (H<sub>2</sub>bpye). While frameworks built of cationic complexes and anionic organic
linkers are already well-known, the seven new compounds described
here represent the first series of frameworks with reversed polarity,
that is, made of anionic complexes and cationic organic linkers. The
compounds have a general formula [OL][MC]<sub>2</sub>·<i>n</i>(<i>guest</i>), where the guest molecules 4,4′-biphenol
(<i>bp</i>), 4-methoxyphenol (<i>mp</i>), 1,4-dimethoxybenzene
(<i>dmb</i>), 1,6-dimethoxynaphtalene (<i>dmn</i>), and 4-nitroanisole (<i>na</i>). Structurally the compounds
can be described as pillared-layer frameworks with layers constructed
of MC anions and linked together by hydrogen-bonded cationic OL pillars.
The guest molecules occupy the galleries between the pillars while
their steric, electronic, and π–π and hydrogen-bonding
capabilities influence the overall structure of the soft frameworks
Organization of accounting policy in Ukraine: problems and solutions of harmonization
Тема облікової політики в нашій державі є актуальною з моменту
проведення реформи національної облікової системи, але й досі протягом
майже 10 років залишаються невирішеними питання змісту, структури, ступенів
деталізації, порядку розкриття, внесення та відображення змін до облікової
політики та облікових оцінок
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