Detailed insights into the formation pathway of CdS and ZnS in solution: a multi-modal in situ characterisation approach.

The high stability, high availability, and wide size-dependent bandgap energy of sulphidic semiconductor nanoparticles (NPs) render them promising for applications in optoelectronic devices and solar cells. However, the tunability of their optical properties depends on the strict control of their crystal structure and crystallisation process. Herein, we studied the structural evolution during the formation of CdS and ZnS in solution by combining in situ luminescence spectroscopy, synchrotron-based X-ray diffraction (XRD) and pair distribution function (PDF) analyses for the first time. The influence of precursor type, concentration, temperature and heating program on the product formation and on the bandgap or trap emission were investigated in detail. In summary, for CdS, single-source precursor (SSP) polyol strategies using the dichlorobis(thiourea)cadmium(II) complex and double-source precursor approaches combining Cd(CH3COO)2·2H2O and thiourea led to the straightforward product at 100 °C, while the catena((m2-acetato-O,O')-(acetate-O,O')-(m2-thiourea)-cadmium) complex was formed at 25 and 80 °C. For ZnS, the reaction between Zn(CH3COO)2·2H2O and thiourea at 100 °C led to the product formation after the crystallisation and dissolution of an unknown intermediate. At 180 °C, besides an unknown phase, the acetato-bis(thiourea)-zinc(II) complex was also detected as a reaction intermediate. The formation of such reaction intermediates, which generally remain undetected applying only ex situ characterisation approaches, reinforce the importance of in situ analysis for promoting the advance on the production of tailored semiconductor materials.

Scanning Compton X-ray microscopy.

X-ray microscopy offers the opportunity to image biological and radiosensitive materials without special sample preparations, bridging optical and electron microscopy capabilities. However, the performance of such microscopes, when imaging radiosensitive samples, is not limited by their intrinsic resolution, but by the radiation damage induced on such samples. Here, we demonstrate a novel, to the best of our knowledge, radio-efficient microscope, scanning Compton X-ray microscopy (SCXM), which uses coherently and incoherently (Compton) scattered photons to minimize the deposited energy per unit of mass for a given imaging signal. We implemented SCXM, using lenses capable of efficiently focusing 60 keV X-ray photons into the sub-micrometer scale, and probe its radio-efficient capabilities. SCXM, when implemented in high-energy diffraction-limited storage rings, e.g., European Synchrotron Radiation Facility Extremely Brilliant Source and PETRA IV, will open the opportunity to explore the nanoscale of unstained, unsectioned, and undamaged radiosensitive materials.

Combining high-energy X-ray diffraction with Surface Optical Reflectance and Planar Laser Induced Fluorescence for operando catalyst surface characterization.

We have combined three techniques, High Energy Surface X-Ray Diffraction (HESXRD), Surface Optical Reflectance, and Planar Laser Induced Fluorescence in an operando study of CO oxidation over a Pd(100) catalyst. We show that these techniques provide useful new insights such as the ability to verify that the finite region being probed by techniques such as HESXRD is representative of the sample surface as a whole. The combination is also suitable to determine when changes in gas composition or surface structure and/or morphology occur and to subsequently correlate them with high temporal resolution. In the study, we confirm previous results which show that the Pd(100) surface reaches high activity before an oxide can be detected. Furthermore, we show that the single crystal catalyst surface does not behave homogeneously, which we attribute to the surface being exposed to inhomogeneous gas conditions in mass transfer limited scenarios.

A multi-purpose reaction cell for the investigation of reactions under solvothermal conditions.

A new versatile and easy-to-use remote-controlled reactor setup aimed at the analysis of chemical reactions under solvothermal conditions has been constructed. The reactor includes a heating system that can precisely control the temperature inside the reaction vessels in a range between ambient temperature and 180 °C. As reaction vessels, two sizes of commercially available borosilicate vessels (Vmax = 5 and 11 ml) can be used. The setup furthermore includes the option of stirring and injecting of up to two liquid additives or one solid during the reaction to initiate very fast reactions, quench reactions, or alter chemical parameters. In addition to a detailed description of the general setup and its functionality, three examples of studies conducted using this setup are presented.

Complexion-mediated martensitic phase transformation in Titanium.

The most efficient way to tune microstructures and mechanical properties of metallic alloys lies in designing and using athermal phase transformations. Examples are shape memory alloys and high strength steels, which together stand for 1,500 million tons annual production. In these materials, martensite formation and mechanical twinning are tuned via composition adjustment for realizing complex microstructures and beneficial mechanical properties. Here we report a new phase transformation that has the potential to widen the application window of Ti alloys, the most important structural material in aerospace design, by nanostructuring them via complexion-mediated transformation. This is a reversible martensitic transformation mechanism that leads to a final nanolaminate structure of α″ (orthorhombic) martensite bounded with planar complexions of athermal ω (a-ω, hexagonal). Both phases are crystallographically related to the parent ß (BCC) matrix. As expected from a planar complexion, the a-ω is stable only at the hetero-interface.

A compact and low-weight sputtering unit for in situ investigations of thin film growth at synchrotron radiation beamlines.

In this work, we report on a highly variable, compact, and light high-vacuum sputter deposition unit designed for in situ experiments using synchrotron radiation facilities. The chamber can be mounted at various synchrotron beamlines for scattering experiments in grazing incidence geometry. The sample position and the large exit window allow to perform x-ray experiments up to large q values. The sputtering unit is easy to mount on existing experimental setups and can be remote-controlled. In this paper, we describe in detail the design and the performance of the new sputtering chamber and present the installation of the apparatus at different 3rd generation light sources. Furthermore, we describe the different measurement options and present some selected results. The unit has been successfully commissioned and is now available for users at PETRA III at DESY.

Mid-term effectiveness of behavioral and psychodynamic inpatient treatments of severe obesity based on a randomized study.

BACKGROUND: The objective of this study was to compare the effectiveness of psychodynamic and behavioral inpatient treatments of severely obese patients regarding weight and distress. METHODS: In a longitudinal study obese patients (body mass index, BMI >or=35) were randomly assigned to behavioral or to psychodynamic inpatient treatment. Mostly female (n = 267; 85%) obese patients with psychiatric and somatic comorbidity (age 20-64 years, BMI 35-74) were examined with standardized self-report scales on distress (SCL-90R), interpersonal problems (Inventory of Interpersonal Problems), eating behavior (Fragebogen zum Essverhalten) and body image (Fragebogen zum Korperbild). RESULTS: During 49 days (mean) of inpatient treatment, patients lost an average of 5.6 kg (4.4%) in the behavioral (n = 130) and 5.7 kg (4.4%) in the psychodynamic setting (n = 137). In both settings, eating behavior, well-being and body image also improved significantly. One year after discharge, return rate was 73%. Forty percent had further reduced their weight (by more than 5% compared to intake), 36% had regained weight, but were still below intake level, and another 24% had increased weight above intake. CONCLUSION: Behavioral and psychodynamic treatments were equally effective reducing weight and distress over 1 year.

[Salivary duct carcinoma of the submandibular gland]. / Speichelgangkarzinome der Glandula submandibularis.

BACKGROUND: Salivary duct carcinoma (SDC) is a rare adenocarcinoma of the salivary glands which usually occurs in the parotid gland (approx. 80%), but is also found in the submandibular gland (approx. 12%) and the minor salivary glands. Due to the low incidence of this tumour-particularly in terms of involvement of the submandibular and minor salivary glands-only limited clinical data is available. PATIENTS/METHOD: In a retrospective investigation, follow-ups of six patients with a SDC of the submandibular gland were analysed and the surgical measures evaluated for their efficiency. RESULTS: At the time of diagnosis, varying tumor stages were present (2xT1, 3xT2, 1xT1). Initial lymph node metastasis was observed in four (66.6%) of the six patients. In all patients, the submandibular gland was resected and neck dissection performed, in two cases (33,3%) this was followed by radiotherapy. Four patients developed a life-threatening local recurrence. Only one patient developed distant metastasis. Two thirds of the patients died due to tumor-related disease after an average of 35.5 months. CONCLUSION: The clinical course of patients with SDC of the submandibular gland exhibits a high (66.6%) rate of local recurrence, crucial for the following clinical course. The treatment of these patients, therefore, must include radical tumor resection as well as tissue resection with a wide margin.