Observation and Structure Determination of an Oxide Quasicrystal Approximant.

We report on the first observation of an approximant structure to the recently discovered two-dimensional oxide quasicrystal. Using scanning tunneling microscopy, low-energy electron diffraction, and surface x-ray diffraction in combination with ab initio calculations, the atomic structure and the bonding scheme are determined. The oxide approximant follows a 3^{2}.4.3.4 Archimedean tiling. Ti atoms reside at the corners of each tiling element and are threefold coordinated to oxygen atoms. Ba atoms separate the TiO_{3} clusters, leading to a fundamental edge length of the tiling 6.7 Å.

Activation and isomerization of n-butane on sulfated zirconia model systems--an integrated study across the materials and pressure gaps.

Butane activation has been studied using three types of sulfated zirconia materials, single crystalline epitaxial films, nanocrystalline films, and powders. A surface phase diagram of zirconia in interaction with SO(3) and water was established by DFT calculations, which was verified by LEED investigations on single-crystalline films and by IR spectroscopy on powders. At high sulfate surface densities a pyrosulfate species is the prevailing structure in the dehydrated state; if such species are absent, the materials are inactive. Theory and experiment show that the pyrosulfate can react with butane to give butene, H(2)O and SO(2), hence butane can be activated via oxidative dehydrogenation. This reaction occurred on all investigated materials; however, isomerization could only be proven for powders. Transient and equilibrium adsorption measurements in a wide pressure and temperature range (isobars measured via UPS on nanocrystalline films, microcalorimetry and temporal analysis of products measurements on powders) show weak and reversible interaction of butane with a majority of sites but reactive interaction with <5 micromol g(-1) sites. Consistently, the catalysts could be poisoned by adding sodium to the surface in a ratio S/Na = 35. Future research will have to clarify what distinguishes these few sites.

Interaction of SO3 with c-ZrO2(111) films on Pt(111).

Single-crystalline sulfated c-ZrO2(111) films of the cubic (c) type have been prepared by reactive deposition of Zr onto Pt(111) in an O2 atmosphere and subsequent exposition to a SO3 atmosphere. The morphology, atomic structure, and composition have been examined by scanning tunneling microscopy, low-energy electron diffraction (LEED), Auger electron spectroscopy, and density functional theory (DFT) calculations. The clean c-ZrO2(111) films display a (2x2) surface structure. During SO3 exposure at room temperature, a clear (radical3xradical3)R30 degrees structure develops. At about 700 K, the SO3-induced (radical3xradical3)R30 degrees structure disappears and the bright (2x2) LEED pattern of the clean ZrO2 films reappears. The energies of plausible c-ZrO2(111)/SO3 structures have been examined by DFT. The (radical3xradical3)R30 degrees structure found in the experiments turned out to be the most stable one for temperatures below 700 K. At temperatures around 700 K, a disordered low coverage structure may exist, which can not be observed by conventional LEED. A comparison of cubic zirconia surfaces with the alternative tetragonal system yields similar results for the SO3 adsorption in the DFT calculations and shows that c-ZrO2 surfaces are good models for the industrial used tetragonal ZrO2 supports.

[Transparent 3-D ultrasound in fetal abnormalities]. / Transparente 3D-Sonographie bei fetalen Fehlbildungen.

AIM: Evaluation of three-dimensional ultrasound (3D-ultrasound) for optimal diagnosis in fetal malformations. METHOD: The 3D-system used consists of a transmitter, position sensor and 3D-workstation. In 38 fetal malformations, verified using real-time two dimensional ultrasound, 101 volume scans were recorded to prove the following functional abilities of the system; (1) Sequential analysis of single images including volume estimation; (2) Simultaneous three plane display (longitudinal, transverse and horizontal planes); (3) Cubic sectional image; (4) Rotating or swinging volume block. RESULTS: In 85% of the cases the 3D-ultrasound clearly achieved a more reliable diagnosis in comparison to the two-dimensional images. Furthermore, the diagnostic information was considerably improved in 44% of the investigated malformations compared to the conventional two-dimensional method. The main advantages of the transparent 3D-technology are (1) Plastic global imaging of the pathological topography (fetal tumours, ureteral stenosis); (2) Exact measurement of irregular volumes (ventricle system, cerebellum); (3) Precise evaluation of fetal disproportions (triploidy, osteochondrodysplasia); (4) Detection of minor malformations. The disadvantages of the method is that all fetal movements during the scanning procedure affect adversely the three-dimensional display. CONCLUSION: The application of 3D-ultrasound in specialized prenatal units recommended.

[Growth of the fetal thyroid gland in the 2nd half of pregnancy--biometric ultrasound studies]. / Wachstum der fetalen Schilddrüse in der II. Schwangerschaftshälfte-Sonographisch-biometrische Untersuchungen.

PURPOSE: Determination of normal values for fetal thyroid size in the 2nd half of pregnancy. METHOD: In 211 pregnant women (completed 20th to 41st week for pregnancy) without thyroid disease the fetal thyroid was measured and characterized by 5 parameters: right lobe transverse and p.a. diameter, left lobe transverse and p.a. diameter, right lobe and left lobe transverse including trachea. The level of measurement was a horizontal section of the neck with circular image of the trachea (centrally) and with the carotids as lateral limiting markers. RESULTS: The trend lines and regression coefficients of the parameters are shown in relation to week of pregnancy. The transverse diameter of both thyroid lobes including the trachea grows from 10 mm (20th week of pregnancy) to 20 mm (40th week of pregnancy). The transverse and p.a. diameters of either lobe double in the 2nd half of pregnancy. CONCLUSION: The normal values presented can help in early diagnosis of fetal thyroid hypertrophy.

[Methods, value and limits of prenatal hearing diagnosis]. / Methode, Aussagefähigkeit und Grenzen pränataler Hördiagnostik.

An intrauterine sound test was developed for monitoring prenatal hearing disorders and evaluated concerning its efficacy and practical feasibility. The procedure is based on the fetesto capacity react upon exogenous sound stimulation. An acoustic stimulation was achieved by a noise generator placed directly on the maternal abdomen in the proximity of the fetal ear. Successful stimulation was monitored by sonographic means expressed as fetal child movements in 447 pregnant women at the end of the 26th to the 37th week of gestation. The most favourable time for an intrauterine hearing test is between the 30th and 32nd week of gestation. The quantity of amniotic liquor, placental location and pathological pregnancies influences the test results. Efficiency and limits of prenatal hearing diagnostics are discussed.

[Studies on the occurrence of Listeria in Cheese]. / Untersuchungen zum Vorkommen von Listerien im Käse.

Various outbreaks of Listeria registered in the USA and Europe after eating cheese were the motive to investigate different cheese sorts of the GDR-production on the occurrence of Listeria species. Out of 100 samples of different cheese brands 11 curdled milk cheeses (11%) showed Listeria innocua, an nonpathogenic Listeria species.

[Diagnostic value of molecular weight related urinary protein electrophoresis in normal total protein excretion]. / Diagnostische Wertigkeit der molekulargewichtsbezogenen Harnproteinelektrophorese bei normaler Gesamteiweissausscheidung.

The electrophoresis of urinary proteins related to the molecular weight in SDS-polyacrylamide gels stood the test for the clarification of the cause of proteinurias. Also in normal excretion of the total protein the analysis of protein is reasonable after concentration of the urine. In the electrophoretic separation of 104 urinary specimens with a maximum protein content of 0.15 g/l in 44 cases a normal protein pattern was found. In 60 cases pathological patterns occurred which in their protein composition greatly corresponded to the damage within the nephron to be expected in the different clinical diagnoses. The results show that the SDS-polyacryl amide gel electrophoresis is suitable for the early recognition and differentiation of injuries of the kidneys.

[Amyloidosis of the kidneys in Crohn disease]. / Amyloidose der Nieren beim Morbus Crohn.

At the instance of the variegated anamnesis of a patient with Crohn's disease the unusually rapid development of a secondary amyloidosis of the kidneys is described. Crohn's disease became manifest at the 17th year of age. The severe course of the disease of the last four years with relapsing intraabdominal abscesses and multiple formations of fistulae might be significant for the pathogenesis of the amyloidosis. If the local complications of Crohn's disease are controlled then the amyloidosis still threatens the patient's life. In case the inflammatory process could be cured the consequence would as expected be the alleviation of the amyloidosis. An additional colchicine therapy may then accelerate the process of healing. However, the nature of Crohn's disease is uncertain.

[Status of ultrasound and roentgen diagnosis in prenatal detection of osteochondrodysplasias]. / Zum Stellenwert der Ultraschall- und Röntgendiagnostik bei der pränatalen Erfassung letaler Osteochondrodysplasien.

Ultrasound and X-ray investigation have a specific but complementary importance within the prenatal recording of lethal osteochondrodysplasia. In the prenatal diagnoses of thanatophoric dysplasia, asphyxiating thoracic dysplasia, chondrodysplasia punctata and achondroplasia we present our procedure for the investigation. All pregnant women are examined by ultrasound. Where the sonographical findings--according to our previous definition for the above mentioned diseases--suggest that they may be present we recommend referral to an institution with highly-specialized diagnostic possibilities for further investigation. Already in the II. trimester of pregnancy it is possible to make such group diagnoses by ultrasound. To give further specificity to the findings prenatal X-ray investigation should be done preferably in the III. trimester. The importance of confirming the diagnosis by either postnatal or postmortem X-ray investigation should be emphasized.

[Aminoglycoside nephropathy]. / Aminoglykosidnephropathie.

Aminoglycosides lead to an increase of number and size of secondary lysosomiotics in the cells of the renal size of secondary lysosomes in the cells of the renal tubuli. Myeloid bodies appear in the lysosomes. As a sequel of the aminoglycoside antibiotics accumulated in the kidney a rhythmic change of the function of the cells of the tubuli with hyperenzymuria, decreased reabsorption of low molecular weight proteins, decreased concentration of urine and decreased glomerular filtration develops. Despite continued drug exposure these deviations are reversible. Simultaneous application of cephalotin, dextran or furosemid increase the toxic effect. A summarizing hypothesis concerning the aminoglycoside-induced nephropathy is presented which takes into consideration the specific receptor binding of the aminoglycosides at the membrane of the tubulus, their accumulation in the lysosomes and their ways in the cell of the tubulus. The lysosomes are regarded as primary working point of the aminoglycosides.

[Intrapartum peridural analgesia and blood pressure of patients with H-gestosis (author's transl)]. / Periduralanalgesie und Blutdruckverhalten intra partum bei Patientinnen mit H-Gestose.

Blood pressures were measured by dry methods, prior to, during, and after analgesia under controlled conditions, in 43 patients with combination of intrapartum peridural analgesia, target-oriented therapeutic infusions, and H-gestosis. Both systolic and diastolic blood pressures dropped with significant, with blood pressure amplitudes staying constant. The same effect was recordable, due to sympathicus blockade, in response to complementary use of antihypertensives. Intrapartum inclusion of peridural analgesia in H-gestosis therapy is recommended by the authors on account of their own favourable experience.

[Peridural analgesia a full-term delivery of low-pain childbirth (author's transl)]. / Schmerzarme geburt durch Periduralanalgesie bei terminierter Entbindung.

Reported in this paper is a combination of "single shot" peridural analgesia with termed delivery, in the context of 100 patients. The analgesic method was applied individually to any of the women involved, depending on aggravating nociperception, all under compulsory cardiotocographic control. The results are given with reference to both objective parameters and interviews with the patients. The authors' own modification seems to be suitable for large-scale routine use.