98 research outputs found
Acute upper extremity arterial thrombosis and stroke in an unresected pheochromocytoma
Pheochromocytoma is a rare cause of hypertension in the general population. Only isolated reports show an association with acute obstructive arterial thrombosis. A 50-year-old chronically noncompliant woman with a known unresected pheochromocytoma presented to the emergency department with ataxia. Imaging confirmed a right-sided ischemic stroke. During her hospital stay, the patient developed signs consistent with acute right upper extremity ischemia resulting from occlusion in the distal right subclavian, axillary, and proximal brachial arteries. Emergent open thrombectomy was successfully performed. In patients with an unresected pheochromocytoma, one must consider acute arterial thrombosis as a rare but potentially limb-threatening and even life-threatening complication
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Monitoring the chemistry of self-healing by vibrational spectroscopy - Current state and perspectives
Self-healing materials are designed to heal damage caused by, for example, mechanical stress or aging such that the original functionality of the material is at least partially restored. Thus, self-healing materials hold great promise for prolonging the lifetime of machines, particularly those in remote locations, as well as in increasing the reliability and safety associated with functional materials in, for example, aeronautics applications. Recent material science applications of self-healing have led to an increased interest in the field and, consequently, the spectroscopic characterization of a wide range of self-healing materials with respect to their mechanical properties such as stress and strain resistance and elasticity was in the focus. However, the characterization of the chemical mechanisms underlying various self-healing processes locally within the damaged region of materials still presents a major challenge. This requires experimental techniques that work non-destructively in situ and are capable of revealing the chemical composition of a sample with sufficient spatial and temporal resolution without disturbing the healing process. Along these lines, vibrational spectroscopy and, in particular Raman spectroscopy, holds great promise, largely due to the high spatial resolution in the order of several hundreds of nanometers that can be obtained. This article aims to summarize the state of the art and prospective of Raman spectroscopy to contribute significant insights to the research on self-healing materials - in particular focusing on polymer and biopolymer materials
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Ruthenium(II)-bis(4'-(4-ethynylphenyl)-2,2':6', 2''-terpyridine) - A versatile synthon in supramolecular chemistry. Synthesis and characterization
A homoleptic ethynyl-substituted ruthenium(II)-bisterpyridine complex representing a versatile synthon in supramolecular chemistry was synthesized and analyzed by NMR spectroscopy, mass spectrometry and X-ray diffractometry. Furthermore, its photophysical properties were detailed by UV/Vis absorption, emission and resonance Raman spectroscopy. In order to place the results obtained in the context of the vast family of ruthenium coordination compounds, two structurally related complexes were investigated accordingly. These reference compounds bear either no or an increased chromophore in the 4Ì€-position. The spectroscopic investigations reveal a systematic bathochromic shift of the absorption and emission maximum upon increasing chromophore size. This bathochromic shift of the steady state spectra occurs hand in hand with increasing resonance Raman intensities upon excitation of the metal-to-ligand charge-transfer transition. The latter feature is accompanied by an increased excitation delocalization over the chromophore in the 4Ì€-position of the terpyridine. Thus, the results presented allow for a detailed investigation of the electronic effects of the ethynyl substituent on the metal-to-ligand charge-transfer states in the synthon for click reactions leading to coordination polymers
Multimodal nonlinear imaging of atherosclerotic plaques differentiation of triglyceride and cholesterol deposits
Cardiovascular diseases in general and atherothrombosis as the most common of its individual disease entities is the leading cause of death in the developed countries. Therefore, visualization and characterization of inner arterial plaque composition is of vital diagnostic interest, especially for the early recognition of vulnerable plaques. Established clinical techniques provide valuable morphological information but cannot deliver information about the chemical composition of individual plaques. Therefore, spectroscopic imaging techniques have recently drawn considerable attention. Based on the spectroscopic properties of the individual plaque components, as for instance different types of lipids, the composition of atherosclerotic plaques can be analyzed qualitatively as well as quantitatively. Here, we compare the feasibility of multimodal nonlinear imaging combining two-photon fluorescence (TPF), coherent anti-Stokes Raman scattering (CARS) and second-harmonic generation (SHG) microscopy to contrast composition and morphology of lipid deposits against the surrounding matrix of connective tissue with diffraction limited spatial resolution. In this contribution, the spatial distribution of major constituents of the arterial wall and atherosclerotic plaques like elastin, collagen, triglycerides and cholesterol can be simultaneously visualized by a combination of nonlinear imaging methods, providing a powerful label-free complement to standard histopathological methods with great potential for in vivo application
Multimodal nonlinear imaging of atherosclerotic plaques differentiation of triglyceride and cholesterol deposits
Cardiovascular diseases in general and atherothrombosis as the most common of its individual disease entities is the leading cause of death in the developed countries. Therefore, visualization and characterization of inner arterial plaque composition is of vital diagnostic interest, especially for the early recognition of vulnerable plaques. Established clinical techniques provide valuable morphological information but cannot deliver information about the chemical composition of individual plaques. Therefore, spectroscopic imaging techniques have recently drawn considerable attention. Based on the spectroscopic properties of the individual plaque components, as for instance different types of lipids, the composition of atherosclerotic plaques can be analyzed qualitatively as well as quantitatively. Here, we compare the feasibility of multimodal nonlinear imaging combining two-photon fluorescence (TPF), coherent anti-Stokes Raman scattering (CARS) and second-harmonic generation (SHG) microscopy to contrast composition and morphology of lipid deposits against the surrounding matrix of connective tissue with diffraction limited spatial resolution. In this contribution, the spatial distribution of major constituents of the arterial wall and atherosclerotic plaques like elastin, collagen, triglycerides and cholesterol can be simultaneously visualized by a combination of nonlinear imaging methods, providing a powerful label-free complement to standard histopathological methods with great potential for in vivo application
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Modified bibenzimidazole ligands as spectator ligands in photoactive molecular functional Ru-polypyridine units? Implications from spectroscopy
The photophysical properties of Ruthenium-bipyridine complexes bearing a bibenzimidazole ligand were investigated. The nitrogens on the bibenzimidazole-ligand were protected, by adding either a phenylene group or a 1,2-ethandiyl group, to remove the photophysical dependence of the complex on the protonation state of the bibenzimidazole ligand. This protection results in the bibenzimidazole ligand contributing to the MLCT transition, which is experimentally evidenced by (resonance) Raman scattering in concert with DFT calculations for a detailed mode assignment in the (resonance) Raman spectra
Multifunctional Polyoxometalate Platforms for Supramolecular Light-Driven Hydrogen Evolution
Multifunctional supramolecular systems are a central research topic in light-driven solar energy conversion. Here, we report a polyoxometalate (POM)-based supramolecular dyad, where two platinum-complex hydrogen evolution catalysts are covalently anchored to an Anderson polyoxomolybdate anion. Supramolecular electrostatic coupling of the system to an iridium photosensitizer enables visible light-driven hydrogen evolution. Combined theory and experiment demonstrate the multifunctionality of the POM, which acts as photosensitizer/catalyst-binding-site[1] and facilitates light-induced charge-transfer and catalytic turnover. Chemical modification of the Pt-catalyst site leads to increased hydrogen evolution reactivity. Mechanistic studies shed light on the role of the individual components and provide a molecular understanding of the interactions which govern stability and reactivity. The system could serve as a blueprint for multifunctional polyoxometalates in energy conversion and storage
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Mitochondria Targeted Protein-Ruthenium Photosensitizer for Efficient Photodynamic Applications
Organelle-targeted photosensitization represents a promising approach in photodynamic therapy where the design of the active photosensitizer (PS) is very crucial. In this work, we developed a macromolecular PS with multiple copies of mitochondria-targeting groups and ruthenium complexes that displays highest phototoxicity toward several cancerous cell lines. In particular, enhanced anticancer activity was demonstrated in acute myeloid leukemia cell lines, where significant impairment of proliferation and clonogenicity occurs. Finally, attractive two-photon absorbing properties further underlined the great significance of this PS for mitochondria targeted PDT applications in deep tissue cancer therapy
In Older Patients Treated for Dizziness and Vertigo in Multimodal Rehabilitation Somatic Deficits Prevail While Anxiety Plays a Minor Role Compared to Young and Middle Aged Patients
Objective: Many patients with dizziness and vertigo are of older age. It is still unclear which age-associated factors play a role in the treatment of dizziness and vertigo. Therefore, age-associated characteristics of patients subjected to an interdisciplinary day care approach for chronic vertigo and dizziness were analyzed.Subjects and Methods: 650 patients with chronic dizziness/vertigo subjected to a multimodal vestibular rehabilitation day care program were analyzed. Information concerning age, gender, medical diagnosis, medical consultations, technical diagnostics performed and therapy achieved before attending the clinic were collected. Furthermore, data were gathered using the Vertigo Severity Scale (VSS), Hospital Anxiety and Depression Scale (HADS), Mobility Inventory (MI), as well as the intensity of and the distress due to vertigo/dizziness using visual analog scales. As a follow-up, the VSS, HADS, MI, and the visual analog scales were collected again 6 months after attending the therapy program. Three age groups were compared to each other (<41, 41–65, and >65 years of age).Results: One-third of the patients were older than 65 years. This group had typical diagnoses with mainly organic deficits. In contrast to the dominance of mainly multifactorial, organic deficits the older patients reported less medical consultations, fewer technical diagnostics and even fewer treatments than the younger patients. The elderly scored significantly lower in total VSS, in VSS-V (vestibular-balance subscale), in VSS-A (autonomic-anxiety subscale) and in HADS-anxiety. Psychological diagnoses were clearly associated to the younger patients. 424 patients (65.2%) completed the follow-up questionnaire 6 months after attending the therapy week. The older patients revealed improvements of VSS-V and the Avoidance Alone scale of MI as well as decreased distress due to vertigo/dizziness.Conclusion: In the older patients, who took part in our vestibular rehabilitation program, mainly somatic deficits prevail while anxiety plays a minor role compared to young and middle aged patients. Older patients profited from vestibular rehabilitation especially in mobility and vestibular-balance. Therefore, vestibular rehabilitation programs for the elderly with a focus on physio- and occupational therapeutic interventions and less cognitive behavioral therapy may be reasonable
Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium
The synthesis and characterisation of an asymmetric potential bridging ligand bmptpphz (bmptpphz = 2,17-bis(4-methoxyphenyl)tetrapyrido[3,2-a:2′,3′-c:3′′,2′′-h:2′′′,3′′′-j] phenazine) is presented. This ligand contains a 1,10-phenanthroline (phen) and a 2,9-disubstituted phen sphere and possesses a strong absorbance in the visible. Facile coordination of the phen sphere to a Ru(tbbpy)2 core leads to Ru(bmptpphz) ([(tbbpy)2Ru(bmptpphz)](PF6)2; tbbpy = 4,4′-di-tert-butyl-2,2′-bipyridine). UV-vis, emission, resonance Raman and theoretical investigations show that this complex possesses all properties associated with a Ru(tpphz) ([(tbbpy)2Ru(tpphz)](PF6)2; tpphz = tetrapyrido[3,2-a:2′,3′-c:3′′,2′′-h:2′′′,3′′′-j] phenazine) moiety and that the ligand based absorbances in the vis-part also populate an MLCT like state. The coordination of a Pd-core in the new 2,9-disubstituted phen sphere is possible, leading to a cyclometallation. The tridentate complexation leads to changes in the UV-vis and emission behaviour. Furthermore, the stability of the Pd-coordination is significantly enhanced if compared to the unsubstituted Ru(tpphz). Ru(bmptpphz)PdCl proved to be an active photocatalyst for H2 evolution, albeit with lower activity than the mother compound Ru(tpphz)PdCl2
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