Operando X-ray Absorption Spectroscopy (XAS) Observation of Photoinduced Oxidation in FeNi (Oxy)hydroxide Overlayers on Hematite (α-FeO) Photoanodes for Solar Water Splitting.

An FeNi (oxy)hydroxide cocatalyst overlayer was photoelectrochemically deposited on a thin-film hematite (α-FeO) photoanode, leading to a cathodic shift of ∼100 mV in the photocurrent onset potential. Operando X-ray absorption spectroscopy (XAS) at the Fe and Ni K-edges was used to study the changes in the overlayer with potential in the dark and under illumination conditions. Potential or illumination only had a minor effect on the Fe oxidation state, suggesting that Fe atoms do not accumulate significant amount of charge over the whole potential range.

Chromium (VI) in phosphorus fertilizers determined with the diffusive gradients in thin-films (DGT) technique.

Phosphorus (P) fertilizers from secondary resources became increasingly important in the last years. However, these novel P-fertilizers can also contain toxic pollutants such as chromium in its hexavalent state (Cr(VI)). This hazardous form of chromium is therefore regulated with low limit values for agricultural products even though the correct determination of Cr(VI) in these fertilizers may be hampered by redox processes, leading to false results.

A von Hamos-type hard X-ray spectrometer at the PETRA III beamline P64.

The design and performance of the high-resolution wavelength-dispersive multi-crystal von Hamos-type spectrometer at PETRA III beamline P64 are described. Extended analyzer crystal collection available at the beamline allows coverage of a broad energy range from 5 keV to 20 keV with an energy resolution of 0.35-1 eV.

In vitro SOD-like activity of mono- and di-copper complexes with a phosphonate substituted SALAN-type ligand.

SALEN- and SALAN-based complexes with catalytically active metal centers are very promising small molecules to be utilized as part of antioxidant therapies. Here we discuss a modified SALAN-type molecule armed with two phosphonate groups that significantly increase its water solubility and aid to furnish mono- or dinuclear complexes with Cu ions. The regulation of the SOD-mimicking (i.

Quick extended x-ray absorption fine structure instrument with millisecond time scale, optimized for in situ applications.

In order to learn about in situ structural changes in materials at subseconds time scale, we have further refined the techniques of quick extended x-ray absorption fine structure (QEXAFS) and quick x-ray absorption near edge structure (XANES) spectroscopies at beamline X18B at the National Synchrotron Light Source. The channel cut Si (111) monochromator oscillation is driven through a tangential arm at 5 Hz, using a cam, dc motor, pulley, and belt system. The rubber belt between the motor and the cam damps the mechanical noise.

Polarization studies of resonant forbidden reflections in liquid crystals.

We report the results of resonant x-ray diffraction experiments performed on thick films of a biaxial liquid crystal made of achiral bent-core molecules. Polarization properties of forbidden reflections are observed as a function of the sample rotation angle phi about the scattering vector Q for the first time on a fluid material. The experimental data are successfully analyzed within a tensor structure factor model by taking the nonperfect alignment of the liquid crystal into account.

Unique pitch evolution in the smectic-C+alpha phase.

Employing resonant x-ray diffraction, we observed unique pitch evolutions in the smectic-C*(alpha) phase in mixtures of two antiferroelectric liquid crystals. Our results show that the pitch in this phase continuously evolves across 4 layers, contradicting a theoretical model that predicts that the smectic-C*(FI2) phase intervenes in the smectic-C*(alpha) phase. The phase sequences we found can be explained by another model that includes one type of long-range interaction among smectic layers.

Smectic-Calpha*-smectic-C* phase transition and critical point in binary mixtures.

We have investigated the smectic-Calpha*-smectic-C* (SmCalpha*-SmC*) transition in a series of binary mixtures with resonant x-ray diffraction, differential optical reflectivity, and heat capacity measurements. Results show that the phases are separated by a first-order transition that ends at a critical point. We report the observation of such a critical point.

Optical and resonant X-ray diffraction studies confirm a SmC*FI2-SmC* liquid crystal phase sequence reversal.

Employing both null transmission ellipsometry and resonant x-ray diffraction, we confirmed the SmC*FI2-SmC* phase sequence reversal in one liquid crystal compound and specially prepared binary mixtures. This phase sequence reversal was predicted by two recent theoretical advances. Moreover, the temperature range for the SmC*FI2 phase increases significantly in the mixture suggesting that such a phase sequence may exist in other compounds.

Experimental investigations of one liquid-crystal compound exhibiting the no-layer-shrinkage effect near the Sm-A-Sm- C(*) transition.

Three experimental probes have been employed to investigate the nature of the smectic- A -smectic- C ( Sm-A-Sm- C(*) ) phase transition of one liquid-crystal compound showing almost no layer-shrinkage effect through the transition. Results from both x-ray diffraction and optical studies indicate that the compound exhibits a crossover behavior of different molecular packing arrangements within the bulk Sm-A phase window. The calorimetry results show a significant critical anomaly near the Sm-A-Sm- C(*) transition, although it was found to be weakly first order.

Interlayer structures of the chiral smectic liquid crystal phases revealed by resonant X-ray scattering.

The structures of the liquid crystalline chiral subphases exhibited by several materials containing either a selenium or sulphur atom have been investigated using a resonant x-ray scattering technique. This technique provides a unique structural probe for the ferroelectric, ferrielectric, antiferroelectric, and SmC(*)(alpha) phases. An analysis of the scattering features allows the structural models of the different subphases to be distinguished, in addition to providing a measurement of the helical pitch.

Orientational ordering in the chiral smectic-C*FI2 liquid crystal phase determined by resonant polarized x-ray diffraction.

High-resolution resonant polarized x-ray diffraction experiments near the sulfur K edge have been performed on free-standing liquid crystal films exhibiting the chiral smectic-C*FI2 phase. It is widely accepted that this phase has a four-layer repeat unit, but the internal structure of the repeat unit remains controversial. We report different resolved features of the resonant x-ray diffraction peaks associated with the smectic-C*FI2 phase that unambiguously demonstrate that the four-layer repeat unit is locally biaxial about the layer normal and that the measured angle, describing the biaxiality, is in good agreement with optical measurements.

Dynamic structure factor of diamond and LiF measured using inelastic X-Ray scattering.

The dynamic structure factors S(q-->,omega) of diamond and LiF have been measured using inelastic x-ray scattering. The experimental data are compared to results of ab initio calculations, which take into account the interaction of the excited electron with the remaining hole. In diamond, the vicinity of the indirect band gap and its momentum dependence are studied.

[2d interim evaluation of a chemotherapy study on patients with squamous cell carcinomas of the head-neck area. A comparison of 2 therapy regimens: cis-diamminedichloroplatinum (II) and bleomycin versus methotrexate and vindesine].

52 patients with epidermoid cancer of the head and neck region were either treated with cis-DDP and bleomycin (arm A) or with methotrexate and vindesine (arm B). In case of resistance patients were further treated with the alternative regimen (A leads to B or B leads to A). Treatment results are superior in arm A.

[Treatment results of Schmincke tumors].

This is a report on the results of a continuous series of 78 previously untreated patients with a lymphoepithelioma (Schmincke-Regaud), who got their diagnosis and therapy in the Medical Center of the University of Kiel between 1951 and 1980. 90% of the patients were treated by radiotherapy alone, which included the primary in the oropharynx (n = 29) or the nasopharynx (n = 48) as well as the regional lymph nodes regardless of whether they were affected (71%) or not; residual lymph nodes of 8 cases were removed afterwards. Thereby a clinically full regression of the tumor disease was achieved in 85%.

[Results of radiation therapy in malignant hypopharyngeal tumors--a retrospective evaluation of 50 cases (author's transl)].

Fifty cases with malignant tumors of the hypopharynx having been irradiated with cobalt-60 at the Radiological Clinic of the Kiel University between 1965 and 1979 are reported. The cumulative 10-year survival rate amounted to 16%. Age and sex, the histology and mode of growth as well as the stage (mostly III or IV) and the primary site of the tumor had no prognostic significance, whereas the tumor response to treatment proved decisive to the prognosis: of the cases clinically revealing complete regression of the tumor, 32% could finally be regarded as cured.

[Five-year-cure rate of laryngeal cancer in the Kiel clinic. Report of 216 cases from 1960 to 1967 (then director: Prof. Dr. E. Müller) with special reference to indications for surgical or orthovolt x-ray therapy].

Report about the five-years-cure of all cases of carcinoma of the larynx, the Kiel-University-ORL-Department had to engage in with diagnostical and therapeutical treatment within a period of 7 years. Out of the total of 216 patients the absolute survival rate was 144 (= 66,7%) after five years. Cure rate was the best with carcinoma of the true vocal cord (72,8%), less satisfactory with carcinoma of the supraglottic region (61,1%), only 5/14 with carcinoma of the marginal region, and only 2/8 with advanced and widespread tumours of undefinable origin.