Search

Xylem sap of angiosperm species has been found to include low concentrations of polar lipids and nanoparticles, including surfactant-coated nanobubbles. Although the nanoparticles have been suggested to consist of polar lipids, no attempt has been made to determine if nanoparticle and lipid concentrations are related. Here, we examined concentrations of nanoparticles and lipids in xylem sap and contamination control samples of six temperate angiosperm species with a NanoSight device and based on mass spectrometry. We found (1) that the concentration of nanoparticles and lipids were both diluted when an increasing amount of sap was extracted, (2) that their concentrations were significantly correlated in three species, (3) that their concentrations were affected by vessel anatomy, and (4) that concentrations of nanoparticles and lipids were very low in contamination-control samples. Moreover, there was little seasonal difference, no freezing-thawing effect on nanoparticles, and little seasonal variation in lipid composition. These findings indicate that lipids and nanoparticles are related to each other, and largely do not pass interconduit pit membranes. Further research is needed to examine the formation and stability of nanoparticles in xylem sap in relation to lipid composition, and the complicated interactions among the gas, liquid, and solid phases in xylem conduits.

SummaryEmbolism spreading in angiosperm xylem occurs via mesoporous pit membranes between vessels. Here, we investigate how the size of pore constrictions in pit membranes is related to pit membrane thickness and embolism resistance.In three models, pit membranes are modelled as multiple layers to investigate how pit membrane thickness and the number of intervessel pits per vessel determine pore constriction sizes, the probability of encountering large pores, and air-seeding. These estimations were complemented by measurements of pit membrane thickness, embolism resistance, and number of intervessel pits per vessel (n= 31, 31, and 20 species, respectively).Constriction sizes in pores decreased with increasing pit membrane thickness, which agreed with the measured relationship between pit membrane thickness and embolism resistance. The number of pits per vessel affected constriction size and embolism resistance much less than pit membrane thickness. A strong relationship between estimated air-seeding pressures and measured embolism resistance was observed.Pore constrictions provide a mechanistic explanation why pit membrane thickness determines embolism resistance, and suggest that hydraulic safety can be uncoupled from hydraulic efficiency. Although embolism spreading remains puzzling and encompasses more than pore constriction sizes, angiosperms are unlikely to have leaky pit membranes, which enables tensile transport of water.

Water potential measurements are considered the gold standard for determining plant water status and drought stress in nature and horticulture. Plant water potentials are routinely measured destructively using pressure chambers, but that method is labor-intensive and the resulting data are discrete in time. Stem psychrometers, on the other hand, allow monitoring plant water potentials continuously. They are notoriously temperature-sensitive, with a gradient of 1°C between plant and instrument temperature causing a deviation in water potential of up to 8 MPa. To quantify potential effects of thermal gradients in sapwood on stem psychrometry we chose two deeply-rooted chaparral shrubs in southern California as our study systems, Malosma laurina and Heteromeles arbutifolia. Depending on the time of day, sap ascending from deep roots can potentially be much colder or warmer than the air surrounding a stem, thereby creating thermal gradients at the sapwood surface. These gradients were measured with small thermistors placed at different distances from the exposed sapwood surface, while sapwood water potentials were measured with stem psychrometers. Substantial thermal gradients were detected in both species, in some cases exceeding 0.1°C mm-1, with sapwood temperature fluctuating diurnally from being warmer or colder than the outside air. Effects of these gradients on psychrometric water potential readings were complex and varied with the time of day and the direction of the gradient, causing false readings deviating by more than 2 MPa from correct values determined by concurrent pressure chamber measurements. Attempts to simultaneously measure and correct for these gradients were unsuccessful, but placement of stem psychrometers far away from the stem base largely alleviated the problem by allowing sapwood temperatures to equilibrate with air temperatures. We therefore recommend installing stem psychrometers as far away from the stem base as possible and always compare initial readings to pressure chamber measurements for validation.

Septic and haemorhagic shock carry the risk of high mortality. Failure of microcirculation secondary to alterations of haemostasis and fibrinolysis play a major role in the pathogenesis of shock. The aim of this study was to evaluate the clinical relevance of procoagulatory and fibrinolytic activities referring to survival. Therefore, 39 patients (23 to 80 yrs, 16 females, 23 males) suffering from haemorrhagic (n = 21) and septic shock (n = 18) were screened prospectively for plasmatic coagulation and fibrinolysis parameters. Thirteen patients (33.3%) developed lethal outcome. Concerning fibrinolysis, plasminogen was significantly lower in non-survivors by day 1 and plasmin-antiplasmin complex significantly higher by day 4 compared to survivors. Consecutive increase of plasminogen over day 4 and 7 was significantly stronger in survivors. Concerning haemostasis activation, thrombin-antithrombin complex was higher and D-dimers or fibrinogen levels were lower, but not significantly different, in non-survivors compared to survivors. We conclude from these data, that procoagulant activities are increased, but not significantly predictive for the clinical outcome in septic and haemorrhagic shock. By contrast, fibrinolysis, as measured by enhanced capacity and responsiveness, is clearly predictive and plays a significant role for survival, possibly due to its clearing function in microcirculation.

A detailed petroleum geochemical study has been carried out on two Cretaceous carbonate source rock units, the Karababa Formation A Member and the Karabogaz Formation, in the Adiyaman area of SE Turkey. The purpose was to compare the hydrocarbon generation habitat of these two units which appear to be almost identical in terms of their bulk source rock characteristics. Thus, the TOC contents of the Karababa Formation A Member and the Karabogaz Formation are 0.24–3.79% and 0.50–5.86%, respectively. Hydrogen Indices are generally greater than 300 mg HC/ g TOC and both units have similar maturity levels. However, the results of pyrolysis-gas chromatographic analyses showed that the organic matter in the Karababa Formation A Member is richer in sulphur compounds, and the presence of sulphur-rich kerogen resulted in the early generation of hydrocarbons from this unit. Both the dominant activation energy and the frequency factor turned out to be lower for the Karababa Formation A Member. Consequently, oil generation in the Karababa Formation A Member proceeds more rapidly for a given temperature history than it does in the Karabogaz Formation. Moreover, the results of multi-step Py-GC analyses indicated that the composition of hydrocarbons generated in these two carbonate source rocks will be different, particularly during the early stages of maturation. Early-generated oil from the Karababa Formation A Member has the composition of a mature oil, whereas oil from the Karabogaz Formation reaches the same composition at a higher maturity.

The halophytic genus Suaeda (Chenopodiaceae) includes species with the C3 and C4 photosynthetic pathways. North American species of this genus were investigated to determine whether C3 and C4 leaf anatomy are consistent within the two sections of Suaeda, Chenopodina and Limbogermen, present on this continent. All species from section Chenopodina were found to possess C3 anatomy, whereas all species from section Limbogermen were found to be C4 species. Characteristics of leaf anatomy and chloroplast ultrastructure are similar to those reported from C3 and C4 species, respectively, from the Eastern Hemisphere. All species from section Limbogermen have the suaedoid type of leaf anatomy, characterized by differentiation of the mesophyll into palisade parenchyma and a chlorenchymatous sheath surrounding central water-storage tissue, as well as leaf carbon isotope ratios (813C) of above -20. All species from section Chenopodina have austrobassioid leaf anatomy without a chlorenchymatous sheath and 813C values of below -20. According to our literature review, the photosynthetic pathway has now been reported for about half (44) of the Suaeda species worldwide. The C3 and C4 photosynthetic syndromes are with few exceptions distributed along sectional or subsectional lines. These findings throw new light on the infrageneric taxonomy of this genus.

The Space Research Institute of the Austrian Academy, of Sciences (Graz, Austria in cooperation with MPE (Berlin, Germany), GFZ Potsdam (Obs. Niemegk, Germany) IZMIRAN/IOFAN (Moscow, Russian) and IGPP/UCLA (Los Angeles, USA) is designing the magnetic field experiment MAGIBAL (MAGnetic field experiment aboard a martian BALloon) to investigate the magnetic field on the surface of Mars. The dual sensor fluxgate magnetometer is part of the MARS-98/MARS-TOGETHER balloon payload. During a ten days period the balloon will float over a distance of about 2000 km at altitudes between 0 and 4 km. Due to the limited power and telemetry allocation the magnetometer can transmit only one vector per ten seconds and spectral information in the frequency range from 2 – 25 Hz. The dynamic range is ± 2000 nT. The main scientific objectives of the experiment are: • • Determination of the magnetism of the Martian rocks • • Investigation of the leakage of the solar wind induced magnetosphere using the correlation between orbiter and balloon observations • • Measurement of the magnetic field profile between the orbiter and the surface of Mars during the descent phase of the balloon. Terrestrial test flights with a hot air balloon were performed in order to test the original MAGIBAL equipment under balloon flight conditions.

The feasibility and first results of a near sensor digitalization of fluxgate signals (digital fluxgate magnetometer) are presented. Applying the usual magnetometer electronics we have substituted the analogue section by a digital processing unit (DPU). The 2f0 signal is digitized at its second harmonic and mean values are online phase-sensitively calculated. Based on this development we present a completely redesigned magnetometer experiment for applications on planetary surfaces. Sensor and electronics including serial interface have to be in one housing, its weight is less than 150 g and the number of electrical connections is limited to four (power lines+serial link). Applications for the digital magnetometer on Earth are also discussed.

Referring to the magnetometer experiments onboard the Mars-96 balloon, and the magnetometer on EQUATOR-S we present the development of fluxgate magnetometers in the MPE-A Berlin for application on small satellites and balloons. Techniques to overcome limitations of field and time resolution by ranging, compensation and data compression are described. To reduce the costs of the magnetic cleanliness program a transportable magnetic cleanliness facility was developed. Results from the measurement of the INTERBALL subsatellite will be shown. The miniaturization of the fluxgate sensor and its electronic and the influence on noise and on offset drift are presented. The feasibility and first results of a near-sensor digitalization are discussed.

A longitudinal study of 39 casts of pre-operative orthodontically treated unilateral cleft lip and palate children from birth to palate operation was carried out with a special coordinate measuring technique to quantify changes in the maxilla. A significant reduction in width of the alveolar cleft was found. The anterior alveolar arch width remained constant, while the posterior region slightly increased. These results seem to justify treatment with the infant appliance. After measuring casts from 39 preoperatively treated and casts from 62 untreated patients prior to lip operation, a comparison of the mathematical average values between the two groups revealed few differences. This can be explained by referring to the original morphological findings and the different measurements during the preoperative orthodontic treatment, which lead to different changes in segment position prior to lip operation. In a cross section examination this difference could not be found. A sub-classification of the subject matter in primary and secondary clefts revealed that between both types clear differences in the resulting parameters can be observed. This leaves the question, whether the width of the cleft palate is caused by tissue deficiency or by an embedded tongue. Furthermore, how will the orthodontic appliance therapy influence the growth? A greater dislocation of the segments in secondary clefts may be expected in cases where the rest position of the tongue appears caudal. Improved measuring methods to record cleft morphology and more emphasis on the study of soft tissue reactions may help to understand the differing results after preoperative or orthodontic treatment.

The extent and consequences of global land-cover and land-use change are increasingly apparent. One consequence not so apparent is the altered structure of plants belowground. This paper examines such belowground changes, emphasizing the interaction of altered root distributions with other factors and their treatment in models. Shifts of woody and herbaceous vegetation with deforestation, afforestation, and woody plant en- croachment typically alter the depth and distribution of plant roots, influencing soil nutrients, the water balance, and net primary productivity (NPP). For example, our analysis of global soil data sets shows that the major plant nutrients C, N, P, and K are more shallowly distributed than are Ca, Mg, and Na, but patterns for each element vary with the dominant vegetation type. After controlling for climate, soil C and N are distributed more deeply in arid shrublands than in arid grasslands, and subhumid forests have shallower nutrient dis- tributions than do subhumid grasslands. Consequently, changes in vegetation may influence the distribution of soil carbon and nutrients over time (perhaps decades to centuries). Shifts in the water balance are typically much more rapid. Catchment studies indicate that the water yield decreases 25-40 mm for each 10% increase in tree cover, and increases in transpiration of water taken up by deep roots may account for as much as 50% of observed responses. Because models are increasingly important for predicting the consequences of vegetation change, we discuss the treatment of belowground processes and how different treatments affect model outputs. Whether models are parameterized by biome or plant life form (or neither), use single or multiple soil layers, or include N and water limitation will all affect predicted outcomes. Acknowledging and understanding such differences should help constrain predictions of vegetation change.

A longitudinal study of 39 casts of pre-operative orthodontically treated unilateral cleft lip and palate children from birth to palate operation was carried out with a special coordinate measuring technique to quantify changes in the maxilla. A significant reduction in width of the alveolar cleft was found. The anterior alveolar arch width remained constant, while the posterior region slightly increased. These results seem to justify treatment with the infant appliance. After measuring casts from 39 preoperatively treated and casts from 62 untreated patients prior to lip operation, a comparison of the mathematical average values between the two groups revealed few differences. This can be explained by referring to the original morphological findings and the different measurements during the preoperative orthodontic treatment, which lead to different changes in segment position prior to lip operation. In a cross section examination this difference could not be found. A sub-classification of the subject matter in primary and secondary clefts revealed that between both types clear differences in the resulting parameters can be observed. This leaves the question, whether the width of the cleft palate is caused by tissue deficiency or by an embedded tongue. Furthermore, how will the orthodontic appliance therapy influence the growth? A greater dislocation of the segments in secondary clefts may be expected in cases where the rest position of the tongue appears caudal. Improved measuring methods to record cleft morphology and more emphasis on the study of soft tissue reactions may help to understand the differing results after preoperative or orthodontic treatment.

A series of seven Alum Shale samples has been analyzed by pyrolytic, petrologic, and spectroscopic methods. All contain alginitic kerogens at various levels of alteration. Kerogens from four samples appear immature to early mature, whereas three samples are more mature, especially one which is very overmature. Decreasing pyrolysate yields per unit weight of carbon characterize the series. Alum Shale alginite is unlike any other alginite we have studied. Aliphatic carbon is present in all but the highly overmature kerogen, yet only a small proportion of aliphatic moieties is released during high-temperature pyrolysis. Furthermore, all the pyrolysates are very aromatic. The unusual structure of Alum Shale alginite might have been brought about by uranium-related alteration effects. Alternatively, or additionally, its structure might have been directly inherited from biopolymeric or carotenoid-derived precursors in algae and bacteria. Mainly gas and condensate are evolved from Alum Shale kerogen during simulated maturation, and a high proportion (more than 30%) of its originally labile components are progressively and cumulatively converted to “dead carbon”. Available data indicate that the Alum Shale behaves similarly during natural maturation.

In this study dental plaster casts of 31 male and 45 female subjects were measured using the Berlin measurement system and evaluated with the aid of a computer. The parameters of subjects with class III malocclusion, crossbite, open bite and class II/1 malocclusion were compared. The changes were studied longitudinally in the main developmental stages, namely the deciduous, mixed and permanent dentitions. Significant differences were found also following treatment between the malocclusion groups.

Die Autoren stellen ein Messystem fur den Spaltkiefer vor, das in der Lage ist, sehr genaue und differenzierte diagnostische Werte zu liefern. Als Grundlage dienen dreidimensionale Punktkoordinaten, die mit Hilfe eines Verfahrens der Koordinatenmestechnik ermittelt und in einem Computer weiterverarbeitet werden. Das Messystem wird anhand ausgewahlter Ergebnisse von 56 Spalttragern demonstriert.

In the Federal Republic of Germany (FRG), the reprocessing of spent fuel assemblies and the recycling of the recovered plutonium are essential for the final disposal of high-level nuclear waste. In addition, the recycling of uranium and plutonium is an effective measure to avoid proliferation of plutonium for weapons and to reduce the needs of uranium. Therefore, the technology of recycling has been developed in the FRG since 1966. In the prototype boiling water reactor (BWR) of Kahl, in the BWR nuclear power plant at Gundremmingen, and the pressurized water reactor plant at Obrigheim mixed-oxide fuel (MOX) assemblies have been operated with good success. Also, the experience gained at Alkem's MOX fuel fabrication plant is very positive. Reprocessing tests of spent MOX fuel rods have indicated that a nearly homogeneous mixture of PuO/sub 2/ and UO/sub 2/ should be used to achieve a good solubility of MOX fuel in nitric acid. In all, very important experience in safeguarding plutonium and MOX fuel material was gained. 7 figures, 3 tables.

The synthesis of the new Np(III) compound Np(HCOO) 3 is reported and its lattice data, spectroscopic and magnetochemical properties are compared with the refined properties of U(HCOO) 3 . Both compounds are isotypic and crystallize in the rhombohedral lattice of Gd(III) formate. The electronic reflectance and IR spectra have been measured and discussed. Low temperature magnetic susceptibilities indicate an antiferromagnetic transition for U(HCOO) 3 at T N = 12 K. The magnetic moments of 3.70 B.M. (140–300 K) for U(HCOO) 3 and 2.69 B.M. (80–300 K) for Np(HCOO) 3 closely approach the corresponding free ion values.

[(CH3)4N]2MnO4, [(CH3)4N]2TcO4, and [(CH3)4N]2ReO4 are isotypic and crystallize in an antifluoritelike cubic face centered lattice with a=11.09 A (Mn), 11.20 A (Tc), and 11.35 A (Re). The magnetic susceptibilities obey the Curie–Weiss law over the temperature range 77–298 °K with μeff=1.63 μB (Mn), 1.60 μB (Tc), and 1.47 μB (Re). The magnetic moments of [(CH3)4N]2TcO4 and [(CH3)4N]2ReO4 as well as the splitting and vibrational structure of the 2E→2T2 intrashell transition indicate strong Jahn–Teller distortion of TcO42− and ReO42− in the first excited 2T2 state. Tetrahedral crystal field parameters of Δ=−11 kK, Δ=−17 kK, and Δ=−19 kK are derived for MnO42−, TcO42−, and ReO42−. The electron transfer spectra reflect the lower degree of covalency of the Re–O bond in comparison to the Tc–O and Mn–O bond.

In der vorliegenden Arbeit werden dreidimensionale Mesergebnisse, die am regelrechten Gebis, am Schmalkiefer mit Protrusion und an Modellen von Progenie-Patienten gewonnen wurden, verglichen. Die Mesergebnisse wurden in dentale Meswerte, kieferbezugliche Meswerte sowie intermaxillare Vergleichswerte unterteilt. Sie wurden mit Hilfe eines Dreikoordinatenmesgerates und eines Computers ermittelt. Der Autor sieht insbesondere die intermaxillaren Vergleichswerte als eine neue Ausgangsbasis fur die kieferorthopadische Modelldiagnostik an.

At an average uranium content of 3.3 ppb the oceans can be considered as a very low-grade but practically unlimited source of uranium. Some essential chemical aspects of a large-scale sorptive recovery of uranium from seawater are discussed with special emphasis on required sorber properties such as high physical and chemical stability in seawater, fast and selective uptake of uranium, as well as a sufficient loading capacity. Systematic screening tests, including about 200 sorber materials on the basis of organic ion-exchange resins, identified cross-linked poly(acrylamidoximes) as the most promising candidate sorbers. Their uranium uptake closely approaches the uranium content of actually explored uranium ores.

Von den Verfassern wird ein Gerat beschrieben, das im Rahmen der computergestutzten dreidimensionalen Modellanalyse eine hochgenaue Ubertragung eines im Oberkiefer errichteten Koordinatensystems auf den Unterkiefer ermoglicht. Damit wird eine einfache und zugleich befriedigende Losung dieses Problems angeboten.

Magnetization measurements on Ni–Mn alloys with manganese contents between 4.7 and 36.9 at% are performed in gaseous hydrogen up to 11 kbar and under stationary conditions. The magnetization changes caused by the interstitial hydrogen let to distinguish two alloy ranges: one with a complete vanishing of the spontaneous magnetization, below about 20% Mn content, and one with its partial reduction above this Mn concentration, caused by an increasing prominence of the Mn magnetism in the host lattice. The magnetic analysis shows further in the alloy group with Mn content below 20% a pressure hysteresis in respect to the formation and decomposition processes of the hydrogen-metal phases and no pressure hysteresis in the cases of higher Mn concentrations, characterizing alloys above the critical region of the phase separation (hydride phase or homogeneous hydrogen solution). Accompanying measurements of the electrical resistance on separate samples agree with earlier resistance studies. Magnetisierungsmessungen werden an Ni–Mn-Legierungen mit Mangangehalten zwischen 4,7 und 36,9 At% im Hochdruckwasserstoff bis zu 11 kbar unter stationaren Bedingungen durchgegefuhrt. Die durch den interstitiellen Wasserstoff verursachten Magnetisierungsanderungen lassen zwei Legierungsgruppen unterscheiden: eine mit vollstandiger Aufhebung der spontanen Magnetisierung bei Mn-Gehalten unter etwa 20% sowie eine mit nur teilweiser Reduzierung der Magnetisierung bei uber diesem Wert liegenden Mn-Konzentrationen, verursacht durch das Wirksamwerden des Mangan-Magnetismus im Wirtsgitter. Die magnetische Analyse zeigt ferner in der Legierungsgruppe mit den niedrigeren Mn-Gehalten eine Druckhysterese bezuglich der Bildungs- und Zersetzungsprozesse der Metall–Wasserstoff-Phasen und das Fehlen einer solchen Hysterese im Fall der hoheren Mn-Konzentrationen, die damit die Legierungen oberhalb des kritischen Gebietes einer Phasentrennung (Hydridphase oder homogene Wasserstofflosung) charakterisieren. Begleitende Messungen des elektrischen Widerstandes an getrennten Proben zeigen die Ubereinstimmung mit Befunden aus fruheren Widerstandsuntersuchungen.

Die Autoren testeten Gerate, wie sie beispielsweise im Maschinenbau zur Vermessung verschiedenstei Werkstucke verwendet werden, auf ihre Eignung fur die kieferorthopadische Modellvermessung. Auf der Basis eines in der Poliklinik fur Orthopadische Stomatologie des Bereichs Medizin (Charite) der Humboldt-Universitat zu Berlin entwickelten Messystems wurden an 20 Modellen 4268 Punkte mit Hilfe einer Dreikoordinatenmesmaschine und eines Zweikoordinatenmesgerates optisch und mechanisch in Form dreidimensionaler Punktkoordinaten vermessen. Als Vorteile dieser Gerate werden die dreidimensionale Erfassung der Mespunkte mit hoher Genauigkeit, die automatische Registrierung der Meswerte auf maschinenlesbare Datentrager, die Moglichkeit des direkten Anschlusses an einen Rechner, geringer Zeitaufwand fur die Modellanalyse im Verhaltnis zur hohen Aussagekraft, die einfache, leicht von Personen auch geringerer Qualifikation erlernbare Handhabung der Mesgerate, geringer Platzbedarf und einfache Justierung (Orientierung) der Modelle ausgewiesen. Statistisch wird nachgewiesen, das die beschriebenen Mesgerate besonders in Sicht auf eine rechnergestutzte Modellanalyse fur die kieferorthopadische Modellvermessung geeignet sind.

The magnetic fields of Mars have been measured from Phobos 2 with high temporal resolution in the tail and down to an 850-km altitude. During four successive highly elliptical orbits, the position of the bow shock as well as that of a transition layer, the 'planetopause', were identified. Subsequent circular orbits at 6000-km altitude provided the first high-resolution data in the planetary tail and indicate that the interplanetary magnetic field mainly controls the magnetic tail. Magnetic turbulence was also detected when the spacecraft crossed the orbit of Phobos, indicating the possible existence of a torus near the orbit of this moon.

Hydroxylamine derivatives of cross-linked poly(acrylonitriles), so-called poly(acrylamidoxime) resins, are suitable for the accumulation of uranium from natural seawater of pH = 8.1–8.3. Depending on the method of manufacture, these sorbers yield excellent uranium loadings up to some thousand ppm which roughly equals the average uranium content of actually explored uranium ores. The rate of uranium uptake, which is 5-30 ppm/d at room temperature, increases with increasing temperature of seawater. Uranium can be eluted by 1 M HCl with an elution efficiency of more than 90%. Owing to a certain instability of the uranium binding groups in acid eluants, the uranium uptake decreases with increasing number of sorption-elution cycles. Hydroxylamine derivatives of poly(acrylonitrile) are shown to contain simultaneously at least two kinds of functional groups: open-chain amidoxime groups which are stable and cyclic imidoxime groups which are unstable in 1 M HCl. Experimental evidence is presented that the...

Diffuse reflectance (20,000–30,000 cm −1 ) and luminescence (18,000–21,000 cm −1 ) spectra of polycrystalline Na 4 [UO 2 (CO 3 ) 3 ] have been measured in the temperature range of 4.2–300 K; the i.r. (50–2000 cm −1 ) and Raman (50–2000 cm −1 ) spectra have been recorded at room temperature. The vibrational spectra exhibit all frequencies expected for a UO 2 L 3 complex of D 3 h symmetry with bidentate ligands L. The symmetric and asymmetric stretching vibrations of the uranyl ion occur at wave numbers as low as 808 and 843 cm −1 , respectively, indicating strong uranium ← carbonate bonding. The diffuse reflectance spectra consist of four overlapping electronic transitions, the lowest one with origin at 20,680 cm −1 is also seen in emission. The absorption bands are assigned to the spin and parity forbidden components of the π u →δ u and π u →φ u one-electron excitations. From the splitting of the excited configurations π 3 u δ 1 u and π 3 u φ 1 u the spin-orbit coupling constant is calculated to be ζ 5ƒ = 1750 cm −1 . Possible relationships between measurable spectroscopic properties of the uranyl ion and the strength of bonding in the equatorial plane are discussed.

Polarized absorption spectra of technetium(IV) and rhenium(IV) in trigonal single crystals of (C2H5NH3)2 [SnCl6] and (C2H5NH3)2[SnBr6] have been measured in the range of 8000 to 2800 Å at 298 and 77 °K. The crystal point group is D3d and the metal ions occupy sites of D3d-symmetry too. The observed excited levels arise from both π24d3 and π23d4 configurations; the different temperature and polarisation dependence of d → d intra-shell and π → d metal reduction transitions is discussed. Experimental values of the parameters Dq (cubic) and υ (trigonal) are reported. The nephelauxetic ratio β55 is evaluated from the 4A2g→2T2g intrasubshell transitions. The electron transfer spectra suggest the optical electronegativity xopt = 2.3 for Tc(IV) and xopt = 2.1 for Re(IV).

The complex anions [TcIV(NCS)6]2− and [TcV(NCS)6]− are prepared and isolated as [(CH3)4N]-salts. They form a redox system the potential of which is found to be E25°C° = + 0·53V in 1 M H2SO4. I.R. spectra indicate nitrogen bonding. Electronic spectra exhibit strong metal reduction bands. According to conductance measurements the d2 complex proves to be considerably more stable. [(CH3)4N][Tc(NCS)6] crystallizes in the rhombohedral system with cell dimensions of a = 8·84 A and α = 82°56′; the magnetic moment of μeff293°K = 2·65 B.M. suggests a trigonal stretching of the ligand framework.

A cross-linked polyacryl resin containing amidoxime or related functional groups is capable of concentrating uranium from natural sea water. The resin presents a uranium loading of more than 3000 ppm; moreover it has a higher selectivity, uptake rate, and attrition stability than hydrous titanium oxide

The 4T1g(t4 2g e1 g) → 6A1g(t3 2g e2 g) phosphorescence spectrum of manganese (II) in single crystals of [Mn(CO(NH2)2)6] (ClO4)2 has been recorded in the temperature range of 4.2 to 298 K. With decreasing temperature the emission maximum is shifted from 17138 cm-1 (298 K) to 16809 cm-1 (4.2 K). This red shift points to a linear thermal expansion coefficient of α = 24 · 10-6 K-1. Crystal field parameters of Dq = 748 cm-1 and B = 827cm-1 have been calculated from the room temperature absorption and excitation spectra.

Organische Ionenaustauscher wurden auf ihre Eignung als Adsorber fur die Anreicherung von Uran aus Meerwasser gepruft. Ein komplexierendes Polymerharz, das sich durch schnelle Uranaufnahme und hohe Selektivitat auszeichnet, ist imstande, Uran aus naturlichem Meerwasser auf das 260000-fache anzureichern.

The changes of jaws of cleft palate children were examined from birth until after the operative lip closure by the aid of a method of coordinate measurement technique. The examination resulted in a significant reduction of the anterior, medial and posterior cleft width during the preoperative treatment period. The anterior and posterior width of alveolar crest arch remained nearly constant in the examination period. The translation of the anterior poles of the palate segments in the case of the unilateral clefts were more distinct in the transversal direction than in sagittal direction. Values of slope were constant or became little smaller after the orthopedic treatment. After the lip closure we found end-to-end relation resulting from guided growth of the segments having constant arch dimensions. A collapse of the segments could not be observed. Altogether we can say the preoperative orthopedic therapy would give the cleft palate good suppositions for the further development.

In this article results of three-dimensional measurements are compared for normal occlusions, protrusion cases and class III patients. The results were divided into dental measurements values, values related to the jaws and values of the intermaxillary comparison. They were obtained with the help of a three-coordinate measurement device and a computer. The author takes especially the values of intermaxillary comparison into consideration as a new basis for orthodontic diagnosis from cast measurements.

The partial loss of the cohesive metal-metal bonding in interstitial solid solutions of hydrogen in transition metals is compensated by Coulomb interactions. The hydrogen atoms occupy octahedral interstices at high electronegativity of the metal (PdH, NiH, β-VH). Otherwise tetrahedral sites are preferred by crystal field energy (δ-VH, β-TaH, NbH2, etc.). The metal lattice can get distorted by the repulsion of neighbouring atoms, which can be shown by Madelung calculations on β, γ, ζ-NbH and NbH2.