171 research outputs found

    Magnetic Anisotropy and Relaxation of Pseudotetrahedral [N2O2] Bis Chelate Cobalt II Single Ion Magnets Controlled by Dihedral Twist Through Solvomorphism

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    The methanol solvomorph 1 amp; 8201; amp; 8901; amp; 8201;2MeOH of the cobalt II complex [Co LSal,2 amp; 8722;Ph 2] 1 with the sterically demanding Schiff base ligand 2 [1,1 amp; 8242; biphenyl] 2 ylimino methyl phenol HLSal,2 amp; 8722;Ph shows the thus far largest dihedral twist distortion between the two chelate planes compared to an ideal pseudotetrahedral arrangement. The cobalt II ion in 1 amp; 8201; amp; 8901; amp; 8201;2MeOH exhibits an easy axis anisotropy leading to a spin reversal barrier of 55.3 amp; 8197;cm amp; 8722;1, which corresponds to an increase of about 17 amp; 8201; induced by the larger dihedral twist compared to the solvent free complex 1. The magnetic relaxation for 1 amp; 8201; amp; 8901; amp; 8201;2MeOH is significantly slower compared to 1. An in depth frequency domain Fourier transform FD FT THz EPR study not only allowed the direct measurement of the magnetic transition between the two lowest Kramers doublets for the cobalt II complexes, but also revealed the presence of spin phonon coupling. Interestingly, a similar dihedral twist correlation is also observed for a second pair of cobalt II based solvomorphs, which could be benchmarked by FD FT THz EP

    Protocol for a phase 1 homeopathic drug proving trial

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    <p>Abstract</p> <p>Background</p> <p>This study protocol adapts the traditional homeopathic drug proving methodology to a modern clinical trial design.</p> <p>Method</p> <p>Multi-centre, randomised, double-blind, placebo-controlled phase 1 trial with 30 healthy volunteers. The study consists of a seven day run-in period, a five day intervention period and a 16 day post-intervention observation period. Subjects, investigators and the statisticians are blinded from the allocation to the study arm and from the identity of the homeopathic drug. The intervention is a highly diluted homeopathic drug (potency C12 = 10<sup>24</sup>), Dose: 5 globules taken 5 times per day over a maximum period of 5 days. The placebo consists of an optically identical carrier substance (sucrose globules). Subjects document the symptoms they experience in a semi-structured online diary. The primary outcome parameter is the number of specific symptoms that characterise the intervention compared to the placebo after a period of three weeks. Secondary outcome parameters are qualitative differences in profiles of characteristic and proving symptoms and the total number of all proving symptoms. The number of symptoms will be quantitatively analysed on an intention-to-treat basis using ANCOVA with the subject's expectation and baseline values as covariates. Content analysis according to Mayring is adapted to suit the homeopathic qualitative analysis procedure.</p> <p>Discussion</p> <p>Homeopathic drug proving trials using the terminology of clinical trials according GCP and fulfilling current requirements for research under the current drug regulations is feasible. However, within the current regulations, homeopathic drug proving trials are classified as phase 1 trials, although their aim is not to explore the safety and pharmacological dynamics of the drug, but rather to find clinical indications according to the theory of homeopathy. To avoid bias, it is necessary that neither the subjects nor the investigators know the identity of the drug. This requires a modification to the informed consent process and blinded study materials. Because it is impossible to distinguish between adverse events and proving symptoms, both must be documented together.</p> <p>Trial registration</p> <p>ClinicalTrials.gov identifier: NCT01061229.</p

    Experimental assignment of long range magnetic communication through Pd amp; Pt metallophilic contacts

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    Record breaking magnetic exchange interactions have previously been reported for 3d metal dimers of the form [M Pt SAc 4 pyNO2 ]2 M Ni or Co that are linked in the solid state via metallophilic Pt amp; 8943;Pt bridges. This contrasts the terminally capped monomers [M Pt SAc 4 py 2], for which neither metallophilic bridges nor magnetic exchange interactions are found. Computational modeling has shown that the magnetic exchange interaction is facilitated by the pseudo closed shell d8 amp; 8943;d8 metallophilic interaction between the filled Pt2 5dz2 orbitals. We present here inelastic neutron scattering experiments on these complexes, wherein the dimers present an oscillatory momentum transfer dependence of the magnetic transitions. This allows for the unequivocal experimental assignment of the distance between the coupled ions, which matches exactly the coupling pathway via the metallophilic bridges. Furthermore, we have synthesized and magnetically characterized the isostructural palladium analogues. The magnetic coupling across the Pd amp; 8943;Pd bridge is found through SQUID magnetometry and FD FT THz EPR spectroscopy to be much weaker than via the Pt amp; 8943;Pt bridge. The weaker coupling is traced to the larger radial extent of the 5dz2 orbitals compared to that of the 4dz2 orbitals. The existence of a palladium metallophilic interaction is evaluated computationally from potential surface cuts along the metal stretching direction. Similar behavior is found for the Pd amp; 8943;Pd and Pt amp; 8943;Pt systems with clear minima along this coordinate and provide estimates for the force constant for this distortion. The estimated M amp; 8943;M stretching frequencies are found to match experimental observed, polarized bands in single crystal Raman spectra close to 45 cm amp; 8722;1. This substantiates the existence of energetically relevant Pd amp; 8943;Pd metallophilic interactions. The unique properties of both Pt2 and Pd2 constitutes an orthogonal reactivity, which can be utilized for steering both the direction and strength of magnetic interaction

    Therapeutic implications of cellular and molecular biology of cancer stem cells in melanoma

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    Somatic mosaicism and common genetic variation contribute to the risk of very-early-onset inflammatory bowel disease

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    Abstract: Very-early-onset inflammatory bowel disease (VEO-IBD) is a heterogeneous phenotype associated with a spectrum of rare Mendelian disorders. Here, we perform whole-exome-sequencing and genome-wide genotyping in 145 patients (median age-at-diagnosis of 3.5 years), in whom no Mendelian disorders were clinically suspected. In five patients we detect a primary immunodeficiency or enteropathy, with clinical consequences (XIAP, CYBA, SH2D1A, PCSK1). We also present a case study of a VEO-IBD patient with a mosaic de novo, pathogenic allele in CYBB. The mutation is present in ~70% of phagocytes and sufficient to result in defective bacterial handling but not life-threatening infections. Finally, we show that VEO-IBD patients have, on average, higher IBD polygenic risk scores than population controls (99 patients and 18,780 controls; P < 4 × 10−10), and replicate this finding in an independent cohort of VEO-IBD cases and controls (117 patients and 2,603 controls; P < 5 × 10−10). This discovery indicates that a polygenic component operates in VEO-IBD pathogenesis

    Zur Hygiene der Herstellung von Bier und Bierersatzgetränken

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