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The nitridation processes of thin V films in molecular nitrogen at atmospheric pressure in a RTP-system, a conventional tube furnace and a high temperature in situ X-ray diffraction (XRD) reaction chamber with a Pt heating stage were compared. The main differences of these three techniques result from their strongly differing heating rates (RTP 50 K/s, in situ chamber 3 K/s, furnace 0.4 K/s) in combination with effects of traces of oxygen in the N 2 process gas: In the furnace, oxide formation on top of the V film takes place at moderate temperatures during the long heating up period. This oxide layer acts as diffusion barrier for nitrogen and prevents nitride formation at higher temperatures. In RTP, due to the fast ramp up to the process temperature no substantial V oxide layer is formed and nitridation of the entire V film proceeds rapidly. In the in situ XRD chamber, strong VN peaks show up above 800°C and only a few weak peaks indicate the presence of some oxide too. According to special RTP experiments, UV radiation emitted from the tungsten halogen lamps in the RTP system does not play a crucial role for the activation and dissociation of the molecular nitrogen in RTP.

Die Reaktion von ReNCl2(PMe2Ph)3 mit MoCl4(NCEt)2 in CH2Cl2 fuhrt zur Bildung des heteronuklearen Dreikernkomplexes [{(Me2PhP)3(EtCN)ClRe≡N–}2MoCl4][MoNCl5]. Das Anion [MoNCl5]2– resultiert vermutlich aus einer Ubertragung des Nitridoliganden vom Re- zum Mo-Atom. Die luftempfindliche Verbindung ist paramagnetisch mit einem magnetischen Moment von μeff = 2,87 B.M. bei Raumtemperatur. Ab 140 K sinkt es bis auf 1,74 B.M. bei 20 K. Der Komplex kristallisiert orthorhombisch in der Raumgruppe Pca21 mit a = 2430(1), b = 1328(1), c = 2436,3(2) pm, Z = 4. Die Nitridobrucken sind mit Bindungswinkeln Re–N–Mo von 164° und 167° nahezu linear. Die Re–N-Abstande von 169 und 170 pm konnen mit Dreifachbindungen interpretiert werden; die Abstande Mo–N von 210 und 211 pm entsprechen Einfachbindungen. Im Anion [MoNCl5]2– betragt der Mo≡N-Abstand 167 pm. Die Hydrolyse des Dreikernkomplexes fuhrt zur Spaltung einer Nitridobrucke und Bildung von (Me2PhP)3(EtCN)ClRe≡N–MoOCl4. Die Verbindung ist paramagnetisch mit μeff = 1,71 B.M. bei Raumtemperatur. Sie kristallisiert orthorhombisch in der Raumgruppe Pbca mit a = 1718,5(4), b = 2037(1), c = 2041,1(7) pm, Z = 8. Im Zweikernkomplex ist die [MoOCl4]–-Gruppe mit einem Abstand Mo–N = 246,5 pm nur schwach an den Nitridoliganden koordiniert, wahrend der Abstand der Re–N-Dreifachbindung von 168,1 pm gegenuber einer terminalen Bindung nahezu unverandert ist. Der Winkel Re≡N–Mo betragt 165,6°. Synthesis and Structure of Two- and Threenuclear Heterometallic Complexes with Nitrido Bridges between Re and Mo The reaction of ReNCl2(PMe2Ph)3 with MoCl4(NCEt)2 yields the heterometallic threenuclear complex [{(Me2PhP)3(EtCN)ClRe≡N–}2MoCl4][MoNCl5]. The anion [MoNCl5]2– presumably results from a transfer of the nitrido ligand from the Re to the Mo atom. The air-sensitive compound is paramagnetic with μeff = 2.87 B. M. at room temperature. A reduction of the magnetic moment to 1.74 B.M at 20 K starts at 140 K. The complex crystallizes in the orthorhombic space group Pca21 with a = 2430(1), b = 1328(1), c = 2436.3(2) pm, Z = 4. With bond angles Re–N–Mo of 164° and 167° the nitrido bridges are almost linear. The distances Re–N of 169 and 170 pm can be interpreted with triple bonds. The Mo–N bond lengths of 210 and 211 pm correspond to single bonds. In the anion [MoNCl5]2– the distance Mo≡N is 167 pm. Hydrolysis of the threenuclear complex results in a cleavage of one of the nitrido bridges to yield (Me2PhP)3(EtCN)ClRe≡N–MoOCl4. The compound is paramagnetic with μeff = 1.71 B.M. at room temperature. It crystallizes in the orthorhombic space group Pbca with a = 1718.5(4), b = 2037(1), c = 2041.1(7) pm, Z = 8. In the dinuclear complex the [MoOCl4]– unit is only weakly coordinated to the nitrido ligand with Mo–N = 246.5 pm, while the distance of the Re≡N bond of 168.1 pm is almost unchanged in comparison with a terminal bond. The bond angle Re≡N–Mo is 165.6°.

Endocytosed Shiga toxin is transported from the Golgi complex to the endoplasmic reticulum in butyric acid-treated A431 cells. We here examine the extent of this retrograde transport and its regulation. The short B fragment of Shiga toxin is sufficient for transport to the ER. The B fragment of cholera toxin, which also binds to glycolipids, is transported to all the Golgi cisterns, but cannot be localized in the ER even after butyric acid treatment. Under all conditions the toxic protein ricin was found predominantly in the trans-Golgi network. There is no transport of endocytosed fluid to the Golgi apparatus or to the ER even after butyric acid treatment and in the presence of Shiga toxin, indicating that transport to the ER, through the trans-Golgi network and the cisterns of the Golgi apparatus, involves several sorting stations. Since Shiga toxin receptors (Gb3) in butyric acid-treated A431 cells seem to have a ceramide moiety with longer fatty acids than in untreated cells, the possibility exists that fatty acid composition of the receptor is important for sorting to the ER. Both retrograde transport and intoxication with Shiga toxin can also be induced by cAMP, supporting the idea that retrograde transport from the Golgi to the ER is required for intoxication. The data suggest that transport to the ER in cells in situ may depend on fatty acid composition and is regulated by physiological signals.

The ordered intermediate rare earth oxides of praseodymium in the composition range between PrO1.714 and PrO1.833 (PrnO2n−2, n = 7, 9, 10, 11, 12) are easily transformed into each other by the variation of temperature and/or oxygen pressure. X-ray powder diffraction patterns of all the intermediate phases are fluorite-related and it is supposed that there are structural relationships between members of the homologous series. Group-subgroup relationships are discussed within this framework, and the probable structure of Pr24O44 is proposed. The unit cell, reported as monoclinic from electron diffraction studies, is assumed to contain two clusters, each with contents Pr7O30, but no definitive structure analysis has been made. From the contrast variation observed in a high-resolution electron microscope (HREM) image of Pr24O44 the relative positions and orientation of these clusters can be inferred, which allows selection of a unique model from those possible. This same image further suggests that the unit cell is actually triclinic. The atomic coordinates have been calculated for the two defect clusters within the unit cell, and have been used for image calculations and simulation comparisons.

The effects of electron beam irradiation on Pr 24 O 44 were followed at high resolution in a JEM-4000EX electron microscope. Two categories of electron beam effects are reported. In one image sequence, the orientational transformation of Pr 24 O 44 from the [100] to the [313] direction was observed to occur. In another sequence, reduction of Pr 24 O 44 to Pr 40 O 72 resulted from intense beam irradiation. Electron diffraction patterns showed the further reduction of the specimen to Pr 7 O 12 and finally to Pr 2 O 3 .

In the oxidation of Pr 7 O 12 to Pr 24 O 44 , the diminished number of defects within the crystal are structurally redistributed. Both structures have a direct relationship to the fluorite lattice for the arrangement of the metal and the oxygen atoms. The defect cluster in these structures consists of two vacancies within the oxygen sublattice that are paired along the [111] direction of the fluorite cell. The transition from one phase to the other is very often accompanied by twinning and also by the formation of antiphase boundaries. It is shown here that twin domains can be related to the loss of symmetry during transformation from the fluorite-related rhombohedral Pr 7 O 12 to the triclinic Pr 24 O 44 . The family tree for the rare-earth oxygen-deficient fluorite-related structures is used to explain the twinning observed in Pr 24 O 44 .

33 Patienten wurden nach kieferchirurgischen Eingriffen durchschnitt-lich 10 Tage lang mit der gebrauchsfertigen Sondennahrung Nutri-comp®F ernährt. Täglich wurden zwischen 1500 bis 2000 ml (= 1875–2500 kcal) über nasale Plastik-Magensonden verabreicht. Bei 9,1% der Patienten muβte die Ernährung wegen Unverträglichkeit abgebrochen werden. Andere Nebenwirkungen waren Durchfälle (2,9%), Übelkeit (1,2%), Aufstoβen (1,2%), Erbrechen (1,2%). Die mittlere Stuhlhäufigkeit betrug 0,64/Tag. Körpergewicht, Nüchtern-blutzucker, Serumelektrolyte, Flüssigkeitshaushalt, Leberenzyme, Säure-Basen-Haushalt und Gesamteiweiβgehalt des Blutes änderten sich nicht signifikant. Der postoperativ beobachtete Harnstoffanstieg im Serum wird als nicht ernährungsbedingt angesehen.

SUMMARY In situ oxidation and reduction of the oxides of cerium, praseodymium and terbium in a controlled atmosphere and temperature have been studied utilizing a high-voltage electron microscope. Experiments were carried out in the environmental cell of the Berkeley KRATOS EM 1500 HVEM at temperatures between 298 K and 1023 K in an atmosphere of oxygen, hydrogen or vacuum. Electron diffraction patterns revealed the course of small fragments of the crystalline oxides. In nearly all cases, the degree of reduction recorded was greater than expected from equilibrium tensimetric studies in the absence of an electron beam. Furthermore, reoxidation appeared to be more sluggish and to a lesser extent than is observed in specimens outside the microscope.

33 patients, who underwent maxillo-facial surgery, were fed with the instant formula diet Nutricomp F via a nasogastric tube for a mean time of 10 days. According to intolerance tube feeding had to be interrupted in 3 patients. Other side effects of nutrition with Nutricomp F were diarrhea (2,9%), nausea (1,2%), vomiting (1,2%) and eructation (1,2%). The mean frequency of defecation was 0,64/day. Glucose content of the blood, water balance, body weight, serum electrolytes, liver enzymes, acid-base-balance and the protein content of the serum did not change significantly. The postoperative increase of urea content in the serum is believed to be independent from formula diet.

The influence of two beta-adrenoceptor antagonists, propranolol and pindolol, on the haemodynamic effects of papaverine, isoprenaline and noradrenaline was investigated in 9 male patients with first degree essential hypertension. Propranolol and pindolol were given according to a doubleblind, crossover scheme. Heart rate and blood pressure were measured before and after each treatment. Propranolol 670 microgram/kg i.v. reduced the supine and standing systolic blood pressures by 2.3% and 1.6%, respectively. Similarly, the intravenous administration of pindolol 35 microgram/kg reduced supine and standing systolic blood pressure by 5.5% and 8.3% respectively (clinically insignificant). Neither drug affected diastolic blood pressure. Following propranolol, there were moderate reduction in supine and standing heart rates, respectively by 24% and 20% (p < 0.001). Similarly, but to a lesser extent, pindolol reduced supine and standing heart rate by 12% and 17% (p < 0.001). The effects of papaverine, which, at 1.5 mg/kg i.v. reduced systolic blood pressure by 5-10% and increased heart rate by 8-15%, were not significantly influenced by the beta-blockers. The blood pressure and heart rate responses to isoprenaline, on the other hand, were attenuated or inhibited by both beta-blockers. While the beta-blockers inhibited the beta-adrenoceptor component of noradrenaline, the pressor component of noradrenaline, which is mediated through the alpha-adrenoceptors, was not influenced by propranolol, but was inhibited after pindolol. It is concluded that pindolol differs qualitatively from propranolol in that it inhibited both the alpha and beta-adrenoceptor effects of noradrenaline.