Nanosecond X-Ray Photon Correlation Spectroscopy on Magnetic Skyrmions.

We report an x-ray photon correlation spectroscopy method that exploits the recent development of the two-pulse mode at the Linac Coherent Light Source. By using coherent resonant x-ray magnetic scattering, we studied spontaneous fluctuations on nanosecond time scales in thin films of multilayered Fe/Gd that exhibit ordered stripe and Skyrmion lattice phases. The correlation time of the fluctuations was found to differ between the Skyrmion phase and near the stripe-Skyrmion boundary. This technique will enable a significant new area of research on the study of equilibrium fluctuations in condensed matter.

The fluctuation-dissipation measurement instrument at the Linac Coherent Light Source.

The development of new modes at x-ray free electron lasers has inspired novel methods for studying fluctuations at different energies and timescales. For closely spaced x-ray pulses that can be varied on ultrafast time scales, we have constructed a pair of advanced instruments to conduct studies targeting quantum materials. We first describe a prototype instrument built to test the proof-of-principle of resonant magnetic scattering using ultrafast pulse pairs. This is followed by a description of a new endstation, the so-called fluctuation-dissipation measurement instrument, which was used to carry out studies with a fast area detector. In addition, we describe various types of diagnostics for single-shot contrast measurements, which can be used to normalize data on a pulse-by-pulse basis and calibrate pulse amplitude ratios, both of which are important for the study of fluctuations in materials. Furthermore, we present some new results using the instrument that demonstrates access to higher momentum resolution.

Medial radio-carpal arthrodesis in three cats with a 2.0 mm locking maxillofacial plate system.

The medical records of three cats that were presented with severe carpal injury requiring radiocarpal arthrodesis were reviewed. Medial plating using the Compact 2.0 LOCK™ system was performed in all three cases. Although screw positioning may be difficult because of the large distance between the holes of the plate and the relatively large size of screws, plate loosening or metacarpal fractures did not occur. Long-term clinical and radiographic follow-up (6 months to 4.5 years) revealed excellent outcome in two cats. In the third cat, the radiocarpal joint did not undergo complete fusion. At four and a half years following surgery, recurrence of forelimb lameness was associated with breakage of the plate.

Treating patients with driving phobia by virtual reality exposure therapy - a pilot study.

OBJECTIVES: Virtual reality exposure therapy (VRET) is a promising treatment for patients with fear of driving. The present pilot study is the first one focusing on behavioral effects of VRET on patients with fear of driving as measured by a post-treatment driving test in real traffic. METHODS: The therapy followed a standardized manual including psychotherapeutic and medical examination, two preparative psychotherapy sessions, five virtual reality exposure sessions, a final behavioral avoidance test (BAT) in real traffic, a closing session, and two follow-up phone assessments after six and twelve weeks. VRE was conducted in a driving simulator with a fully equipped mockup. The exposure scenarios were individually tailored to the patients' anxiety hierarchy. A total of 14 patients were treated. Parameters on the verbal, behavioral and physiological level were assessed. RESULTS: The treatment was helpful to overcome driving fear and avoidance. In the final BAT, all patients mastered driving tasks they had avoided before, 71% showed an adequate driving behavior as assessed by the driving instructor, and 93% could maintain their treatment success until the second follow-up phone call. Further analyses suggest that treatment reduces avoidance behavior as well as symptoms of posttraumatic stress disorder as measured by standardized questionnaires (Avoidance and Fusion Questionnaire: p < .10, PTSD Symptom Scale-Self Report: p < .05). CONCLUSIONS: VRET in driving simulation is very promising to treat driving fear. Further research with randomized controlled trials is needed to verify efficacy. Moreover, simulators with lower configuration stages should be tested for a broad availability in psychotherapy.

Effects of diminished steric protection at phosphorus on stability and reactivity of oxaphosphirane complexes.

Readily available P-tBu substituted Li/Cl phosphinidenoid complexes react with carbonyl compounds to furnish sterically almost unhindered oxaphosphirane complexes that reveal new and surprisingly facile intra- and intermolecular ring expansion reactions. 1,3,2-Dioxaphosphole complex formation is explained by DFT calculations through diastereoselective carbonyl group-induced ring cleavage of an oxaphosphirane intermediate.

"Low-coordinate" 1,2-oxaphosphetanes - a new opportunity in coordination and main group chemistry.

While 1,2σ5λ5-oxaphosphetanes are well known intermediates from the Wittig-reaction, no 1,2σ3λ3-oxaphosphetanes have been described, so far. Herein, we present the first synthesis of 1,2σ3λ3-oxaphosphetanes derived from their κP-Mo(CO)5 complexes and first investigations towards metal coordination and P-oxidation. Bonding, ring strain energy and potential retro-[2+2] cycloaddition reactions of the 1,2-oxaphosphetane ring were studied by DFT methods.

Hartmann characterization of the PEEM-3 aberration-corrected X-ray photoemission electron microscope.

Aberration correction by an electron mirror dramatically improves the spatial resolution and transmission of photoemission electron microscopes. We will review the performance of the recently installed aberration corrector of the X-ray Photoemission Electron Microscope PEEM-3 and show a large improvement in the efficiency of the electron optics. Hartmann testing is introduced as a quantitative method to measure the geometrical aberrations of a cathode lens electron microscope. We find that aberration correction leads to an order of magnitude reduction of the spherical aberrations, suggesting that a spatial resolution of below 100 nm is possible at 100% transmission of the optics when using x-rays. We demonstrate this improved performance by imaging test patterns employing element and magnetic contrast.

Ring opening of a sterically crowded 1,2-oxaphosphetane complex.

The first example of a ring opening reaction of a 1,2-oxaphosphetane complex is reported, i.e., water in the presence of [Li(12-crown-4)]Cl furnished a C-OH functional phosphinito complex. Employment of the latter in ring forming reactions with Me2ECL2 (E = Si, Ge) using different nitrogen bases is also described.

Polarization driven conductance variations at charged ferroelectric domain walls.

Conducting domain walls (CDWs) in ferroelectric materials are promising candidates for applications in a manifold of nanoscale, optoelectronic devices. Characterization of their microscopic properties, however, remains challenging due to their small dimension and highly insulating environment. Here, we inspect individual CDWs in single-crystalline LiNbO3 by the combination of photoemission electron microscopy (PEEM) and second harmonic generation (SHG) microscopy. While SHG unveils the overall domain wall inclination angle α, PEEM is sensitive to local conductance variations, both at and away from the domain wall. Thus, the two imaging techniques deliver complementary information over a large field of view. In agreement with earlier theoretical predictions we find that the local conductance is dictated by α and reveal a quantitative connection between them. Our results help to elucidate the electronic structure of CDWs and underline the value of PEEM as a non-contact characterization tool for mapping local conductance variations in highly resistive environments.

Synthesis and reactions of C-phosphanylated thiazol-2-thiones.

The facile regioselective synthesis of the P(iii) substituted thiazol-2-thione 2 is presented. Reaction of 2 with hydrogenperoxide-urea, elemental sulfur and selenium resulted in P(v) chalcogenide thiazol-2-thiones 3-5. All compounds were characterized using (31)P, (1)H, (13)C NMR, IR and elemental analyses and, additionally, by the single-crystal X-ray diffraction technique. Oxidative desulfurization of the 5-phosphinoylated thiazol-2-thione 3 using hydrogenperoxide led to the first C-phosphanoyl substituted thiazolium salt (6). Deprotonation of 6 and in situ reaction with the cyclooctadiene rhodium(i) chloride dimer yielded thiazol-2-ylidene rhodium(i) complex 7 which was confirmed by NMR spectroscopy and ESI-MS spectrometry.

A novel route to C-unsubstituted 1,2-oxaphosphetane and 1,2-oxaphospholane complexes.

The synthesis of 1,2-oxaphosphetane complexes and 1,2-oxaphospholane complex bearing only substituents at phosphorus is reported using the reaction of Li/Cl phosphinidenoid complex with 2-iodoethanol or 3-bromo-propane-1-ol and the subsequent dehydrohalogenation using KHMDS. In contrast, the reaction of complex with (t)BuLi leads selectively to the formation of phosphinito complex .

CPh3 as a functional group in P-heterocyclic chemistry: elimination of HCPh3 in the reaction of P-CPh3 substituted Li/Cl phosphinidenoid complexes with Ph2C=O.

P-CPh3 substituted oxaphosphirane complexes 3 were prepared using Li/Cl phosphinidenoid complexes 2 (M = Cr, Mo, W) and benzaldehyde. Employing 2 and benzophenone resulted in the formation of oxaphospholane complexes 4 and 5, the former bearing a benzo[c]-1,2-oxaphospholane and the latter a novel pentacyclic P-ligand. According to DFT studies the latter P-heterocycle arises from formal dimerization of a transient benzofused 2-phosphafurane complex 8, one of the fragments undergoing water-catalyzed [1,3]H shift (4) and the other (11) formed via elimination of HCPh3.

Synthesis of a monomolecular anionic FLP complex.

Despite intense research in FLP chemistry, nothing is known about monomolecular anionic FLPs and/or complexes thereof. Herein, synthesis and reaction of the first anionic FLP complex is described using [(OC)5W{(Me3Si)2HCP(H)OLi(12-crown-4)}], Cy2BCl and subsequent deprotonation by KHMDS. The obtained anionic FLP complex reacts readily with CO2 in a concerted manner.

Synthesis of the first 2,3-dihydro-1,2,3-azadiphosphete complex.

Synthesis of the first 2,3-dihydro-1,2,3-azadiphosphete complex was achieved via thermal reaction of a 2H-azaphosphirene complex in o-xylene, whereby a 2,5-dihydro-1,3-diaza-2,5-diphosphinine complex and a further unidentified byproduct were formed; the structure of the title compound was established through an X-ray single-crystal diffraction study.

[The compatibility of ronidazol in racing pigeons in a controlled clinical study]. / Verträglichkeit von Ronidazol bei Brieftauben im kontrollierten klinischen Test.

Ronidazol is often used in racing pigeons for the treatment of Trichomonas infections and diseases. Therefore, in this study, the compatibility of the drug was examined by oral application over 7 days. For this purpose a randomized blind study was performed using four different groups (control group, 10 mg = therapy-group, 20 mg = double-dose-group and 40 mg = high-dose-group) of pigeons (Columba livia f. domestica) with 6 male and 6 female birds each. All birds were clinically healthy and between 6 and 12 weeks of age. The application of ronidazol at a dose of 10 mg/racing pigeon did show no side-effect within the duration of the study, e.g. no influence could be seen on clinical, haematological, blood-chemical and pathological parameters. Low-to middle-grade clinical alterations of the gastro-intestinal tract occurred in the high-dose group at day 6 and 7 of the application of the drug. Therefore a fourfold overdosing of ronidazol should be avoided.

Bond-selective nitrile insertion into the 2H-azaphosphirene ring system as induced by tetracyanoethylene.

Competitive reactions of 2H-azaphosphirene metal complexes 1a-c (M =Cr, Mo, W) with 1-piperidinonitrile and tetracyanoethylene in toluene have been observed at elevated temperatures. For the case of complex 1c, the delta5-1,2-azaphospholene complex 2c (as main product) and the 2H-1,4,2-diazaphosphole complex 3c (as by-product) were separated from the product mixture. At ambient temperature and using 1-piperidinonitrile as solvent, bond and regioselective insertion of 1-piperidinonitrile into the P-N bond of 2H-azaphosphirene metal complexes 1a-c (M = Cr, Mo, W) has been achieved in the presence of tetracyanoethylene (TCNE), yielding 2H-1,4,2-diazaphosphole metal complexes 3a-c, analogous reactions in benzo- or acetonitrile afforded the 2H-1,4,2-diazaphosphole tungsten complexes 3d, e. A preliminary study with the 2H-azaphosphirene tungsten complex 1c and 1-piperidinonitrile as solvent has revealed that substoichiometric amounts of TCNE (0.3 equiv) induce approximately 70% conversion of complex 1c. NMR data of the complexes 2c and 3a-e and the X-ray structure of complex 3c are discussed.