Archive for May, 2008
Friday, May 16th, 2008
In 1957, Charles Hard Townes and Arthur Leonard Schawlow, then at Bell Labs, began a serious study of the infrared laser. As ideas were developed, infrared frequencies were abandoned with focus on visible light instead. The concept was originally known as an “optical maser”. Bell Labs filed a patent application ...
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Friday, May 16th, 2008
In 1957, Charles Hard Townes and Arthur Leonard Schawlow, then at Bell Labs, began a serious study of the infrared laser. As ideas were developed, infrared frequencies were abandoned with focus on visible light instead. The concept was originally known as an "optical maser". Bell Labs filed a patent application ...
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Thursday, May 1st, 2008
Hybridization-Sensitive On-Off DNA Probe: Application of the Exciton Coupling Effect to Effective Fluorescence Quenching.
The design of dyes that emit fluorescence only when they recognize the target molecule, that is, chemistry for the effective quenching of free dyes, must play a significant role in the development ...
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Thursday, May 1st, 2008
Bio-Inspired Fabrication of Lotus Leaf Like Membranes as Fluorescent Sensing Materials.
A fluorescent organic small molecule, hexaphenylsilole (HPS), has been used as a sensing material, while a HPS/polymethyl methacrylate composite film with a lotus leaf like structure is prepared by a simple electrospin method. The film ...
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Thursday, May 1st, 2008
Monomer versus Alcohol Activation in the 4-Dimethylaminopyridine-Catalyzed Ring-Opening Polymerization of Lactide and Lactic O-Carboxylic Anhydride.
Model reactions for the 4-dimethylaminopyridine (DMAP)-catalyzed ring-opening polymerization of lactide and the corresponding lactic O-carboxylic anhydride (lacOCA) have been studied computationally at the B3LYP/6-31G(d) level of theory. The solvent effect of ...
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Thursday, May 1st, 2008
Long-Wavelength Fluorescence from 2-Aminopurine-Nucleobase Dimers in DNA.
When 2-aminopurine (2AP) is substituted for adenine in DNA, it is widely accepted that its fluorescence spectrum is essentially unchanged from that of the free fluorophore. We show that 2AP in DNA exhibits long-wavelength emission and excitation bands, in ...
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Thursday, May 1st, 2008
Organocatalytic Multicomponent alpha-Methylenation/Diels-Alder Reactions: A Versatile Route to Substituted Cyclohexenecarbaldehyde Derivatives.
This article describes the design and optimization of an effective organocatalytic three-component domino alpha-methylenation/Diels-Alder reaction to produce vinyl-substituted cyclohexenecarboxaldehydes in a highly regioselective fashion. In these one-pot transformations, 2-formyl-1,3-butadienes (4) were prepared in situ from ...
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Thursday, May 1st, 2008
Diastereo- and Enantiomerically Pure Allylboronates: Their Synthesis and Scope.
Allylboronates are highly attractive reagents for allyl additions. Enantiomerically pure, stable reagents with a stereogenic centre in alpha-position to boron are especially versatile, albeit often difficult to synthesize. Starting from boron-containing allyl alcohols 6 and 7, which ...
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Thursday, May 1st, 2008
Clathrate Formation from Octaazaphthalocyanines Possessing Bulky Phenoxyl Substituents: A New Cubic Crystal Containing Solvent-Filled, Nanoscale Voids.
The synthesis of octaazaphthalocyanine (AzaPc) derivatives, with bulky phenoxyl substituents placed at eight peripheral positions and containing either H(+), Ni(2+) or Zn(2+) ions in their central cavity, is described. The ...
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Thursday, May 1st, 2008
Experimental and Theoretical Approaches Toward Anion-Responsive Tripod-Lanthanide Complexes: Mixed-Donor Ligand Effects on Lanthanide Complexation and Luminescence Sensing Profiles.
A new series of tripods were designed to form anion-responsive, luminescent lanthanide complexes. These tripods contain pyridine, thiazole, pyrazine, or quinoline chromophores combined with amide carbonyl oxygen and ...
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Thursday, May 1st, 2008
Supramolecular Polymerization and Polymorphs of Oligo(p-phenylene vinylene)-Functionalized Bis- and Monoureas.
Bis- and monoureas hybridized with the oligo(p-phenylene vinylene) (OPV) pi-electronic segment and 3,4,5-tridodecyloxyphenyl wedge were synthesized and their supramolecular polymerization in diluted solution, gel formation in concentrated solution, and liquid crystallinity in bulk state were investigated. ...
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Thursday, May 1st, 2008
Torsional Angular Dependence of (1)J(Se,Se) and Fermi Contact Control of (4)J(Se,Se): Analysis of (n)J(Se,Se) (n=1-4) Based on Molecular Orbital Theory.
(n)J(Se,Se) (n=1-4) nuclear couplings between Se atoms were analyzed by using molecular orbital (MO) theory as the first step to investigating the nature of bonded and ...
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Thursday, May 1st, 2008
Individualisierte Therapie mit trizyklischen Antidepressiva. Pharmakogenetik der Depression.
Bei der medikamentösen Behandlung eines depressiven Patienten spricht bei weitem nicht jeder auf das verschriebene Antidepressivum und die gewählte Dosis an. Infolgedessen sind häufig Anderungen der Therapie notwendig. Dies gilt für trizyklische Antidepressiva ebenso wie für alle anderen ...
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Thursday, May 1st, 2008
Trizyklische Antidepressiva als Schlafmittel. Medikamentöse Behandlungsoptionen bei Insomnie.
In der Insomniebehandlung gibt es sowohl psychotherapeutische als auch medikamentöse Behandlungsmöglichkeiten. Durch eine genaue Anamnese, Diagnostik und individuelle Abwägung der möglichen Risiken und Nebenwirkungen kann für die meisten Patienten eine Beschwerdelinderung erbracht bzw. das richtige \"Schlafmittel\" gefunden werden. ...
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Thursday, May 1st, 2008
Trizyklika als Co-Analgetika. Therapieoption bei chronischen Schmerzen.
Anhand der klinischen Studien können trizyklische Antidepressiva und die dual wirksamen neuen Substanzen sowohl für die Behandlung von neuropathischem Schmerz als auch für die Therapie des Nozizeptorschmerzes eingesetzt werden. Die Entscheidung welchen Arzneistoff der jeweilige Patient bekommt, sollte aufgrund ...
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Thursday, May 1st, 2008
Therapie mit trizyklischen Antidepressiva. Vor- und Nachteile der TZA.
Auch 50 Jahre nach ihrer Entdeckung nehmen nicht-selektive Monoamin-Rückaufnahme-Inhibitoren (NSMRI) - so genannte trizyklische Antidepressiva - einen wichtigen Platz in der medikamentösen Depressionsbehandlung ein. Aus dem Spektrum der verfügbaren Substanzen sollte ein Präparat aufgrund seines klinischen Wirkprofils ...
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Thursday, May 1st, 2008
Medizinische Chemie der Trizyklischen Antidepressiva. Targets und Stereochemie.
Antidepressiva gehören zu den am häufigsten verschriebenen Arzneistoffen in Deutschland. Das Verordnungsvolumen zu Lasten der gesetzlichen Krankenkassen betrug in 2006 insgesamt 767 Mio. Tagesdosen, wovon 255,6 Mio. auf die trizyklischen Antidepressiva (TCA) entfielen. Dabei sind Depressionen längst nicht ...
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Thursday, May 1st, 2008
Wirkungsmechanismen der tri- und tetrazyklischen Antidepressiva. Adaptive Veränderung und Neuordnung von Transmittersystemen.
Die Bezeichnung tri- und tetrazyklische Antidepressiva charakterisiert auch heute noch eine Substanzklasse mit ähnlichen chemischen Grundstrukturen und ähnlichen pharmakologischen Eigenschaften. Sie hemmen die Wiederaufnahme von Neurotransmittern an noradrenergen und serotonergen Synapsen.
Müller WE.
...
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Thursday, May 1st, 2008
Entdeckung der trizyklischen Antidepressiva. Serendipität oder die Faszination von \"Zufällen\"
Die unverhoffte Auffindung der thymoleptischen Eigenschaften von Imipramin, dem ersten trizyklischen Antidepressivum, feierte im Jahre 2007 das 50-jährige Jubiläum. Diese Entdeckung bedeutete nicht nur einen Durchbruch in der Therapie der depressiven Erkrankungen, sie legte auch den ...
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Thursday, May 1st, 2008
GPCR - Struktur des humanen beta(2)-Rezeptors aufgeklärt!
Die detaillierte Kenntnis der dreidimensionalen Struktur von Targetproteinen in Lösung oder kristallinem Zustand spielt bei der Entwicklung von Arzneistoffen eine ganz entscheidende Rolle. Mit der Lösung der Kristallstruktur des humanen beta(2)-Rezeptors ist es nunmehr erstmals gelungen, die dreidimensionale Struktur ...
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Thursday, May 1st, 2008
H5N1 mit einem besonderen Gespür für Zuckerketten.
Es ist ruhiger geworden um die Vogelgrippe und um H5N1. Und das obwohl in Indonesien seit Beginn des Jahres 15 Menschen an aviärer Influenza erkrankt und 12 davon verstorben sind (Stand 8.4.2008) und obwohl 2007 in Deutschland 326 Infektionen ...
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Thursday, May 1st, 2008
Im nächsten Heft: Alpha-Blocker und 5-Alpha-Reduktase-Inhibitoren.
Medizinische Chemie der alpha(1)-Blocker5alpha-Reduktase-Inhibitoren - Benigne Prostatahyperplasie und vieles mehrArterielle Hypertonie - was gibt es Neues?Benigne Prostata-Hyperplasie und Benignes Prostata-SyndromDie Bedeutung der Mutterkorn-Alkaloide als Arzneistoffealpha(1)-Adrenozeptor-AntagonistenStellenwert der Phytotherapie beim benignen Prostata-Syndrom.
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Thursday, May 1st, 2008
Comparison of supercritical fluid and Soxhlet extractions for the isolation of nitro compounds from soils.
Supercritical fluid extraction (SFE) with CO(2), a clean and rapid alternative to conventional Soxhlet extraction, was investigated for the extraction of nitro compounds from soil samples. Quantitative extraction by SFE was ...
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Thursday, May 1st, 2008
High throughput screening and antioxidant assay of dibenzo[a,c]cyclooctadiene lignans in modified-ultrasonic and supercritical fluid extracts of Schisandra chinensis Baill by liquid chromatography-mass spectrometry and a free radical-scavenging method.
Dibenzo[a,c]cyclooctadiene lignans of Schisandra chinensis Baill are well known because of their hepatoprotective activity, antioxidant activity, and anticancer ...
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Thursday, May 1st, 2008
Nucleic acid sensor for insecticide detection.
Nucleic acid sensor based on polyaniline (PANI) has been fabricated by covalently immobilizing double stranded calf thymus (dsCT) DNA onto perchlorate (ClO(-) (4))-doped PANI film deposited onto indium-tin-oxide (ITO) glass plate using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) chemistry. These dsCT-DNA-PANI-ClO(4)/ITO and ...
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