New Pathophysiological Aspects of Growth and Prevention of Kidney Stones

Kidney stones probably grow during crystalluria by crystal sedimentation and aggregation (AGN) on stone surfaces. This process has to occur within urinary transit time (UT) through the kidney before crystals are washed out by diuresis. To get more information, we studied by spectrophotometry the formation and AGN of Ca oxalate (Ca Ox) crystals which were directly produced in urine of 30 stone patients and 30 controls by an oxalate (Ox) titration. Some tests were also performed after removing urinary macromolecules (UMs) by ultrafiltration. To induce rapid crystallization, high Ox additions (0.5–0.8 mM) were necessary. The most important finding was retardation of crystal AGN by UM. In urine of 63% of controls but only 33% of patients, no AGN was observed during an observation of 60 minutes (P < 0.05). Also growth and sedimentation rate of crystals were significantly reduced by UM. For stone metaphylaxis, especially for posttreatment residuals, avoiding dietary Ox excesses to prevent crystal formation in the kidney and increasing diuresis to wash out crystals before they aggregate are recommended

Determinationof oxidation induction time and temperature bY DSC: Results of round robin tests

Results obtained from three round robin tests, performed in 1998, 2000 and 2004, are summarized and presented. Oxidation Induction Time (OITtime) and Oxidation Induction Temperature (OITtemp) on six different grades of polyethylene were measured by DSC. The measured data were collected by Empa and evaluated using a robust statistical method concerning repeatability and reproducibility standard deviation. The results of the tests indicate that the determination of OITtime is associated with a high degree of uncertainty, especially for low OITtime values. Thus, OITtemp measurements could be a valuable alternative for testing less stabilized or non-stabilized polyolefin in particular. However, OITtemp data reveal that the ability to distinguish between different polymer samples decreases drastically as OITtemp values increas

New-on-line method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS)

A new online method to analyse water isotopes of speleothem fluid inclusions using a wavelength scanned cavity ring down spectroscopy (WS-CRDS) instrument is presented. This novel technique allows us simultaneously to measure hydrogen and oxygen isotopes for a released aliquot of water. To do so, we designed a new simple line that allows the online water extraction and isotope analysis of speleothem samples. The specificity of the method lies in the fact that fluid inclusions release is made on a standard water background, which mainly improves the δ D robustness. To saturate the line, a peristaltic pump continuously injects standard water into the line that is permanently heated to 140 °C and flushed with dry nitrogen gas. This permits instantaneous and complete vaporisation of the standard water, resulting in an artificial water background with well-known δ D and δ18O values. The speleothem sample is placed in a copper tube, attached to the line, and after system stabilisation it is crushed using a simple hydraulic device to liberate speleothem fluid inclusions water. The released water is carried by the nitrogen/standard water gas stream directly to a Picarro L1102-i for isotope determination. To test the accuracy and reproducibility of the line and to measure standard water during speleothem measurements, a syringe injection unit was added to the line. Peak evaluation is done similarly as in gas chromatography to obtain &delta D; and δ18O isotopic compositions of measured water aliquots. Precision is better than 1.5 ‰ for δ D and 0.4 ‰ for δ18O for water measurements for an extended range (−210 to 0 ‰ for δ D and −27 to 0 ‰ for δ18O) primarily dependent on the amount of water released from speleothem fluid inclusions and secondarily on the isotopic composition of the sample. The results show that WS-CRDS technology is suitable for speleothem fluid inclusion measurements and gives results that are comparable to the isotope ratio mass spectrometry (IRMS) technique

Transition-metal silicides formed by ion mixing and by thermal annealing: Which species moves?

The moving species during the formation of Pt2Si, Ni2Si, and CrSi2 by both ion mixing with 300–600 keV Xe ions and thermal annealing is identified with inert markers using backscattering spectrometry. Samples of metal-on-silicon and silicon-on-metal have been used, evaporated on SiO2 substrates with two very thin markers (Mo for Pt2Si, W for Ni2Si and CrSi2) placed at the metal–silicon interface, and at the bottom interface with the SiO2 substrate. Monitoring the separation of the two markers as a function of the amount of silicide formed determines the ratio of atomic transport through the growing silicide layer. The results establish that the dominant moving species in both silicide formation processes is the same for the refractory metal-silicide CrSi2, e.g., Si, whereas different atomic transport ratios are found in the case of the near-noble metal silicides Pt2Si and Ni2Si. This outcome is discussed in terms of high-temperature effects during thermal formation of transition-metal silicides

Observation of Ising-like critical fluctuations in frustrated Josephson junction arrays with modulated coupling energies

We report the results of ac sheet conductance measurements performed on fully frustrated square arrays of Josephson junctions whose coupling energy is periodically modulated in one of the principal lattice directions. Such systems are predicted to exhibit two distinct transitions: a low-temperature Ising-like transition triggered by the proliferation of domain walls and a high-temperature transition driven by the vortex unbinding mechanism of the Beresinskii-Kosterlitz-Thouless (BKT) theory. Both the superfluid and dissipative components of the conductance are found to exhibit features which unambiguously demonstrate the existence of a double transition whose properties are consistent with the Ising-BKT scenario.Comment: To be published in Physica C (Proceedings of the 2nd European Conference in School Format 'Vortex Matter in Superconductors'

Laser annealing of silicon on sapphire

Silicon-implanted silicon-on-sapphire wafers have been annealed by 50-ns pulses from a Q-switched Nd : YAG laser. The samples have been analyzed by channeling and by omega-scan x-ray double diffraction. After irradiation with pulses of a fluence of about 5 J cm^–2 the crystalline quality of the silicon layer is found to be better than in the as-grown state

Sputtered W–N diffusion barriers

The thermal stability of reactively sputtered tungsten–nitrogen alloy thin films is investigated for the application as diffusion barriers in silicon contact metallizations. The composition of W–N barriers is varied over a wide range including pure W. Aluminum, gold, and silver are used as low resistivity overlayers. Metallurgical interactions at temperatures ranging from 500 to 900 °C are studied. Incorporating nitrogen into tungsten advantageously stabilizes all three systems. The overall failure takes place rapidly above critical temperatures that depend on both the metal overlayer and the microstructure of the barrier. In some cases, W–N alloys can effectively prevent interdiffusion at temperatures as high as 800 °C for 30 min

From awareness raising to sustainable behaviour change in school: the WASH in school road map

Development organisations working in the WASH sector tend to focus on their preferred methodologies for Hygiene and Sanitation (H&S) promotion, while the sustainability of an intervention depends much more on how the methodology is implemented and whether an enabling environment is in place. In 2014, Caritas Switzerland in Kenya started a learning and critical review process on how to improve its WASH in school interventions to finally make the step from raising students’ awareness on good H&S practices to sustainable behaviour change. As a result of this process, a number of lessons on how to foster the enabling environment were learned, based on which the WASH in school road map was developed. This article presents, for each phase of the WASH in school road map, the main lessons learned and how they have been implemented in Kenya

Effects of the Protein Kinase Inhibitor PKC412 on Gene Expression and Link to Physiological Effects in Zebrafish Danio rerio Eleuthero-Embryos

To identify molecular effects of the antineoplastic agent protein kinase C inhibitor 412 (PKC412) (midostaurin), we applied gene expression profiling in zebrafish using whole-genome microarrays. Behavioral, developmental, and physiological effects were investigated in order to analyze for correlations between altered gene expression profiles with effects on development and physiology. Zebrafish blastula-stage embryos were exposed for 6 days postfertilization to nominal levels of 2 and 40 μg/l PKC412. Among the 259 and 511 altered transcripts at both concentrations, respectively, the expressions of genes involved in the circadian rhythm were further investigated. Alteration of swimming behavior was not observed. Pathways of interest affected by PKC412 were angiogenesis, apoptosis, DNA damage response, and response to oxidative stress. Angiogenesis was analyzed in double-transgenic zebrafish embryos Tg(fli1a:EGFP)y1;Tg(gata1:dsRed)sd2; no major defects were induced by PKC412 treatment at both concentrations. Apoptosis occurred in olfactory placodes of embryos exposed to 40 μg/l, and DNA damage was induced at both PKC412 concentrations. However, there were no significant effects on reactive oxygen species formation. This study leads to the conclusion that PKC412-induced alterations of gene transcripts are partly paralleled by physiological effects at high, but not at low PKC412 concentrations expected to be of environmental relevanc