Search results for "Ryle"

Protonenvermittelter Ringschluss eines negativ photochromen, Azulen‐basierten Diarylethens

2020

Auf Protonen ansprechende photochrome Moleküle sind aufgrund ihrer Fähigkeit, auf nicht-invasive schnelle optische Stimuli zu reagieren, und wegen der ubiquitären Bedeutung von Protonierungs- und Deprotonierungsprozessen, sehr interessant. Üblicherweise befinden sich die sauren/basischen Stellen dieser Moleküle an Heteroatomen, die orthogonal zum photoaktiven π-Zentrum ausgerichtet sind. In dieser Arbeit wird Azulen, ein protonensensitiver reiner Kohlenwasserstoff, in das Gerüst eines Diarylethen-Photoschalters eingebaut. Dieser zeigt einen bisher ungekannten, protonenvermittelten, negativ photochromen Ringschluss. Veränderungen seiner optischen Eigenschaften durch Protonierung, sowohl in d…

Common genetic variation of the cholesteryl ester transfer protein gene strongly predicts future cardiovascular death in patients with coronary arter…

2003

OBJECTIVES We sought to evaluate the association between cholesteryl ester transfer protein (CETP) genotypes and the risk of future cardiovascular mortality in patients with coronary artery disease (CAD). BACKGROUND Polymorphisms of the CETP gene influence CETP activity and high-density lipoprotein (HDL) cholesterol concentration and might affect the long-term prognosis and response to statin therapy in patients with CAD. METHODS We used serum samples and deoxyribonucleic acid collected at baseline from a prospective cohort of 1,211 patients with CAD prospectively followed up (median follow-up of 4.1 years), 82 of whom experienced a fatal cardiovascular event. The CETP/C-629A and I405V poly…

Warm white LED light by frequency down-conversion of mixed yellow and red Lumogen®

2013

This work reports on the benefits and promising opportunities offered by white LED hybrid technology, based on a mixing perylene-based dyes in order to obtain a warm white light for frequency-down conversion. In a standard Ce:YAG-based white LED, the white light appears cold due to the weakness of red wavelength components in the emission spectrum. In order to obtain a warmer white, one possible solution is to add a red phosphor to the yellow one to move the chromatic coordinates properly, though the luminous efficiency drastically decreases due to the increased light absorption of the coating layer. It is generally believed that the low efficiency of warm white LEDs is the main issue today…

White LED light obtained by frequency down-conversion of perylene-based dyes

2012

Lichtaktivierte Sensoren zur empfindlichen Amindetektion

2017

Unsere neue, einfache und akkurate colorimetrische Methode basiert auf Diarylethenen (DAEs) zur schnellen Detektion einer grosen Vielfalt primarer und sekundarer Amine. Die Sensoren bestehen aus aldehyd- oder ketonsubstituierten Diarylethenen, die selektiv ausgehend vom geschlossenen Isomer eine amininduzierte Entfarbungsreaktion eingehen. Somit konnen diese Sensoren zum gewunschten Zeitpunkt durch Lichteinstrahlung aktiviert werden und erlauben eine Empfindlichkeit der Amindetektion bis hinab zu 10−6 m in Losung. Zusatzlich ermoglicht die Immobilisierung auf Papier den Nachweis biogener Amine wie Cadaverin in der Gasphase oberhalb eines Grenzwerts von 12 ppbv innerhalb von 30 Sekunden.

Light-Activated Sensitive Probes for Amine Detection

2017

Our new, simple, and accurate colorimetric method is based on diarylethenes (DAEs) for the rapid detection of a wide range of primary and secondary amines. The probes consist of aldehyde- or ketone-substituted diarylethenes, which undergo an amine-induced decoloration reaction, selectively to give the ring-closed isomer. Thus, these probes can be activated at the desired moment by light irradiation, with a sensitivity that allows the detection of amines at concentrations as low as 10exp−6 M in solution. In addition, the practical immobilization of DAEs on paper makes it possible to detect biogenic amines, such as cadaverine, in the gas phase above a threshold of 12 ppbv within 30 seconds. P…

Proton‐Gated Ring‐Closure of a Negative Photochromic Azulene‐Based Diarylethene

2020

Abstract Proton‐responsive photochromic molecules are attractive for their ability to react on non‐invasive rapid optical stimuli and the importance of protonation/deprotonation processes in various fields. Conventionally, their acidic/basic sites are on hetero‐atoms, which are orthogonal to the photo‐active π‐center. Here, we incorporate azulene, an acid‐sensitive pure hydrocarbon, into the skeleton of a diarylethene‐type photoswitch. The latter exhibits a novel proton‐gated negative photochromic ring‐closure and its optical response upon protonation in both open and closed forms is much more pronounced than those of diarylethene photoswitches with hetero‐atom based acidic/basic moieties. …

CCDC 1852850: Experimental Crystal Structure Determination

2019

Related Article: Qiang Chen, Stefan Thoms, Sven Stöttinger, Dieter Schollmeyer, Klaus Müllen, Akimitsu Narita, Thomas Basché|2019|J.Am.Chem.Soc.|141|16439|doi:10.1021/jacs.9b08320

The clinical significance of small, dense low-density lipoproteins

2006

Peak size of low-density lipoproteins (LDL) in humans does not show a normal, but a bimodal distribution and can be separated into two phenotypes, that differ in size, density, physicochemical composition, metabolic behavior, and atherogenicity. These phenotypes have been assigned as pattern A when larger, more buoyant LDL and pattern B when smaller, more dense LDL predominate. Small dense LDL correlates negatively with plasma HDL levels and positively with plasma triglyceride concentrations and is associated with the metabolic syndrome and increased risk for cardiovascular disease. LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart diseas…

Cyclotriveratrylene-Containing Porphyrins

2016

International audience; The C-3-symmetric cyclotriveratrylene (CTV) was covalently bonded via click chemistry to 1, 2, 3, and 6 zinc(II) porphyrin units to various host for C-60. The binding constants, Ka, were measured from the quenching of the porphyrin fluorescence by C-60. These constants vary between 400 and 4000 M-1 and are considered weak. Computer modeling demonstrated that the zinc(II) porphyrin units, [Zn], exhibit a strong tendency to occupy the CTV cavity, hence blocking the access for C-60 to land on this site. Instead, the pincer of the type [Zn]-[Zn] and in one case [Zn]-CTV, were found to be the most probable geometry to promote host-guest associations in these systems.