Molecular entities with doublet or triplet ground states find increasing interest as potential molecular quantum bits (qubits). Complexes with higher multiplicity might even function as qudits and serve to encode further quantum bits. Vanadium(II) ions in octahedral ligand fields with quartet ground states and small zero-field splittings qualify as qubits with optical read out thanks to potentially luminescent spin-flip states.
View Article and Find Full Text PDFIn spite of intense, recent research efforts, luminescent transition metal complexes with Earth-abundant metals are still very rare owing to the small ligand field splitting of 3d transition metal complexes and the resulting non-emissive low-energy metal-centered states. Low-energy excited states decay efficiently non-radiatively, so that near-infrared emissive transition metal complexes with 3d transition metals are even more challenging. We report that the heteroleptic pseudo-octahedral d-vanadium(iii) complex VCl(ddpd) (ddpd = ,'-dimethyl-,'-dipyridine-2-yl-pyridine-2,6-diamine) shows near-infrared singlet → triplet spin-flip phosphorescence maxima at 1102, 1219 and 1256 nm with a lifetime of 0.
View Article and Find Full Text PDFLuminescence from Earth-abundant metal ions in solution at room temperature is a very challenging objective due to the intrinsically weak ligand field splitting of first-row transition metal ions, which leads to efficient nonradiative deactivation via metal-centered states. Only a handful of 3d metal complexes ( ≠ 10) show sizable luminescence at room temperature. Luminescence in the near-infrared spectral region is even more difficult to achieve as further nonradiative pathways come into play.
View Article and Find Full Text PDFIntroduction: The association between severe psychiatric disorders and metabolic syndrome is well documented and goes along with a reduced life expectancy. The prevalence of medical comorbidities in individuals suffering from psychiatric disorders in Austria has not yet been examined; aim of this study was to analyze the prevalence of comorbid somatic disorder in individuals diagnosed with psychiatric disorders in Austria.
Methods: Patients (n = 600) with a life-time diagnosis of mood and anxiety disorders undergoing a six-week course of intensive treatment in a psychiatric rehabilitation center were recruited.
Two nanosensors for simultaneous optical measurements of the bioanalytically and biologically relevant analytes temperature ("T"), oxygen ("O"), and pH ("P") have been designed. These "TOP" nanosensors are based on 100 nm-sized silica-coated polystyrene nanoparticles (PS-NPs) doped with a near-infrared emissive oxygen- and temperature-sensitive chromium(III) complex ([Cr(ddpd)][BPh], CrBPh) and an inert reference dye (Nile Red, NR or 5,10,15,20-tetrakis(pentafluorophenyl) porphyrin, TFPP) and are covalently labeled with pH-sensitive fluorescein isothiocyanate (FITC). These emitters can be excited at the same wavelength and reveal spectrally distinguishable emission bands, allowing for ratiometric intensity-based and time-resolved studies in the visible and near-infrared wavelength region.
View Article and Find Full Text PDFThe aim of this cross-sectional study was to test the idea that the psychopathic trait "Fearless dominance" (FD) may be associated with reduced psychological stress symptoms and better stress coping strategies in psychiatric patients, whereas the factor "Self-centered impulsivity" (SCI) may be associated with more stress and maladaptive stress coping. The investigation included 626 individuals with psychiatric disorders treated in a psychiatric rehabilitation program. The participants were tested with the Psychopathic Personality Inventory Revised (PPI-R) and completed several clinical scales measuring stress experience and stress coping (Symptom-Checklist Revised, Trier Inventory for Chronic Stress, The Stress Coping Style Questionnaire 78).
View Article and Find Full Text PDFHypothesis: Carbon dot systems are highly surface sensitive fluorescent nanomaterials. In the presence of specific molecules or ions, the fluorescence properties can be strongly influenced. Often their fluorescent properties are activated or strongly enhanced through passivation agents such as polymer coatings.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2018
The recently reported luminescent chromium(III) complex 1 ([Cr(ddpd) ] ; ddpd=N,N'-dimethyl-N,N'-dipyridine-2-yl-pyridine-2,6-diamine) shows exceptionally strong near-IR emission at 775 nm in water under ambient conditions (Φ=11 %) with a microsecond lifetime as the ligand design in 1 effectively eliminates non-radiative decay pathways, such as photosubstitution, back-intersystem crossing, and trigonal twists. In the absence of energy acceptors, such as dioxygen, the remaining decay pathways are energy transfer to high energy solvent and ligand oscillators, namely OH and CH stretching vibrations. Selective deuteration of the solvents and the ddpd ligands probes the efficiency of these oscillators in the excited state deactivation.
View Article and Find Full Text PDFReversing the metal-to-ligand charge transfer ( MLCT)/metal-centered ( MC) excited state order in iron(II) complexes is a challenging objective, yet would finally result in long-sought luminescent transition-metal complexes with an earth-abundant central ion. One approach to achieve this goal is based on low-energy charge-transfer absorptions in combination with a strong ligand field. Coordinating electron-rich and electron-poor tridentate oligopyridine ligands with large bite angles at iron(II) enables both low-energy MLCT absorption bands around 590 nm and a strong ligand field.
View Article and Find Full Text PDFLOV domains act as versatile photochromic switches servicing multiple effector domains in a variety of blue light sensing photoreceptors abundant in a multitude of organisms from all kingdoms of life. The perception of light is realized by a flavin chromophore that upon illumination reversibly switches from the non-covalently bound dark-state to a covalently linked flavin-LOV adduct. It is usually assumed that most LOV domains preferably bind FMN, but heterologous expression frequently results in the incorporation of all natural occurring flavins, i.
View Article and Find Full Text PDFLight is an important environmental factor for almost all organisms. It is mainly used as an energy source but it is also a key factor for the regulation of multiple cellular functions. Light as the extracellular stimulus is thereby converted into an intracellular signal by photoreceptors that act as signal transducers.
View Article and Find Full Text PDFBacillus subtilis is capable of responding to various kinds of extracellular, potentially harmful stimuli via a stress response pathway, which involves a signal transduction and integration hub, the stressosome, and finally leads to activation of σ(B). One of the different signals initiating the underlying phosphorylation cascade is blue light. While it is known that the bacterial photoreceptor YtvA is responsible for blue light detection, the intramolecular activation mechanism and the structure of this multidomain protein are unknown.
View Article and Find Full Text PDFPhotoreceptors play an important role in plants and bacteria by converting extracellular stimuli into intracellular signals. One distinct class are the blue-light-sensitive phototropins harboring a light-oxygen-voltage (LOV) domain coupled to various effector domains. Photon absorption by the chromophore within the LOV domain results in an activation of the output domain via mechanisms that are hitherto not well understood.
View Article and Find Full Text PDFInt J Pediatr Otorhinolaryngol
April 2006
We report about a boy with the symptoms of Gradenigo's syndrome (abducens nerve palsy, acute otitis media, unilateral headache). The MR imaging showed a sinus vein thrombosis instead of the expected petroapicitis. After 2 weeks of conservative therapy with antibiotics and anticoagulation, without any clinical effort the boy underwent a mastoidectomy.
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