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International audience; In this work, we present a pilot experiment in the experimental storage ring (ESR) at GSI devoted to impact parameter sensitive studies of inner shell atomic processes for low-energy (heavy-) ion-atom collisions. The experiment was performed with bare and He-like xenon ions (Xe 54+ , Xe 52+ ) colliding with neutral xenon gas atoms, resulting in a symmetric collision system. This choice of the projectile charge states was made in order to compare the effect of a filled K-shell with the empty one. The projectile and target X-rays have been measured at different observation angles for all impact parameters as well as for the impact parameter range of ∼35–70 fm.

Eight healthy probands received 1.0 to 1.3 g ethanol per kg body weight within a period of 30 minutes. The average hourly elimination rate of ethanol during the postresorptive phase was found to be 0.18 g/l. No significant increase in the elimination rate was seen either after administration of 200 mg metoprolol per day in slow release form for a period of one week, or after a single dose of 200 mg metoprolol in standard formulation taken at the beginning of ethanol ingestion. On the other hand, long-term administration of metoprolol resulted in a steeper rise and a delayed decrease of blood alcohol concentration. Simultaneous intake of metoprolol and of alcohol in high dosage should be avoided.

International audience; In this contribution, we present an experimental and theoretical study of the proton- and electron- impact excitation effects in helium-like uranium ions in relativistic collisions with different gaseous targets. The experiment was carried out at the experimental storage ring at GSI Darmstadt. Our experimental results are in agreement with predictions of the state-of-the art theory which treats both processes within the relativistic framework.

A comparative expression proteome analysis was carried out by analyzing differential expression patterns of pulse-labelled proteins on two-dimensional gels under standard conditions and during purine nucleotide starvation, followed by mass spectrometric identification of regulated proteins. Based upon the expression patterns, three stimulons could be identified in Lactococcus lactis subsp. cremoris. The Psu proteins (purine starvation up-regulated) had increased synthesis during purine depletion in a purine auxotroph. Among these proteins were enzymes of the purine biosynthesis pathways (PurE, PurS, PurM, PurL), and enzymes involved in the generation of C1 units (GlyA, Fhs). C1 units are primarily required for purine biosynthesis. Upon analysis of the nucleotide sequence preceding the structural genes for these proteins in the L. lactis IL1403 genome sequence showed that all contained PurBox-Pribnov box structures resembling the PurR activated promoters for the purDEK and purCSQLF operons. Most, and possibly all members of the Psu stimulon are thus members of the PurR regulon. Five Psu proteins could not be identified. The second stimulon, the Psd stimulon (purine starvation decreased), whose members are down-regulated during purine depletion, contained proteins related to protein synthesis (PpsB, EF-TS, trigger factor), or to GTPases (FtsZ, EF-TS); or are involved in energy metabolism (GapB, CcpA). No common regulatory elements could be found for members of this stimulon. Two Psd proteins escaped identification. The last, Dcu (decoynine up-regulated), stimulon contained proteins whose synthesis escaped the severe general depression during inhibition of the GMP synthetase by decoynine. This regulon was comprised of mostly glycolytic enzymes (fructose bisphosphate aldolase, enolase, pyruvate kinase) and translation elongation factors (GTPases: EF-TU, EF-G). Two Dcu proteins could not be identified. Out of 28 proteins subjected to mass spectrometry, 19 could be readily identified despite the fact that only the genome sequence of a strain of L. lactis subsp. lactis was available. The two subspecies share about 85% sequence identity, comparable to the genetic distance between Escherichia coli and Salmonella typhimurium. A success rate of 68% indicates that it may be feasible to perform proteomics based upon genomic sequences of relatives outside the genus.

Starting with a 50‐50 wt.% Al‐Ni alloy powder a new process was developed by which an active alumina supported, not pyrophoric Raney-type Ni catalyst is produced. It consists of very finely dispersed nickel of 25‐30 wt.% (specific weight of about 1.2). The Ni is not ferromagnetic. The catalyst is applied in all liquid phase hydrogenations where standard Raney-Ni is used, with the same or higher specific activity. The structure of the catalyst is described using XRD, SAXS, TEM SEM/EDX, and N2-sorption. The catalytic activity measurements were performed in liquid phase hydrogenations at room temperature and atmospheric pressure. ©2000 Elsevier Science B.V. All rights reserved.

In a three-phase study, single oral doses of placebo, followed in 1 week by pyrazinoylguanidine (PZG; 900 mg), followed in 3 weeks by pyrazinoic acid (PZA; 300 mg) were given to 8 normal male subjects. Blood analyses performed 0, 2 and 4 h after administration of placebo or drug revealed that compared to mean 0 h values, PZG and also PZA, but not placebo, decreased mean values for serum glucose, insulin, C-peptide, triglycerides and free fatty acids. In all groups, serum potassium, urea, fibrinogen, high-density lipoprotein and low-density lipoprotein were unchanged. PZA, but not PZG, increased serum uric acid. PZG significantly reduced very-low-density lipoprotein whereas PZA only tended to do so. PZG was well tolerated and without any side effect, but in 7 of the 8 normal volunteers, PZA produced a variable vasomotor response over the blush area of the face and neck lasting from 30 min in 3 subjects to 4 h in 1 subject. Collectively, these results suggest generally similar metabolic responses of normal subjects to PZG and PZA after only a single oral dose of each. Previously, it was unrecognized that acute administration of PZG and PZA could produce such rapid metabolic changes.

Pyrazinoylguanidine (PZG) is a new antihyperglycemic, antihyperlipidemic drug. The current study reports on the development of an animal model in which the favorable metabolic effects of PZG, previously described in diabetic patients, could be reproduced and investigated. Adult male as well as female Sprague-Dawley rats received a single intraperitoneal dose (50 mg/kg) of streptozotocin (STZ). One week later, they received PZG (50 mg/kg i.p.) twice daily for a week. Compared to vehicle (saline-treated controls), PZG reduced plasma concentrations of glucose by 33-70%, triglycerides by 50-70%, nonesterified fatty acids by 17-27%, cholesterol by 10-50%, and glucagon by 18-20%. Hydrochlorothiazide given in a dose of 20 mg/kg i.p. b.i.d for 1 week induced metabolic effects opposite to those of PZG. In the Zucker fatty rat, PZG also lowered plasma glucose and lipid concentrations. These results indicate that PZG ameliorated the abnormalities of plasma glucose and lipid that characterize STZ-diabetic and Zucker fatty rats.

In isolated rat adipocytes stimulated with theophylline (1 mmol/l), pyrazinoylguanidine (PZG) downregulated both lipolysis and cyclic AMP concentrations, raising the possibility that PZG stimulates adipose insulin-sensitive phosphodiesterase. To investigate this directly, we measured PZG's effects on phosphodiesterase activity in rat adipocytes. PZG (10 mumol/l) as well as insulin (0.1-1 mU) increased adipose phosphodiesterase activity, whereas theophylline reduced it. Also investigated were PZG's effects on gluconeogenesis and cyclic AMP in perfused rat liver where PZG decreased gluconeogenesis and cyclic AMP concentrations.

The projectile excitation of high-Z ions has been investigated in relativistic ion-atoms collisions by observing the subsequent x-ray emission. Within this experiment information about the population of the magnetic sublevels has been obtained via an angular differential study of the decay photons associated with the subsequent de-excitation process. In addition, we have observed for the first time the effect of electron-impact excitation in a heavy highly charged ion undergoing a collision with a neutral atom.

A single blind crossover study with washout phases showed that pyrazinoylguanidine (PZG) reduced elevated serum concentrations of urea, triglycerides, and cholesterol in patients with renal insufficiency. Pyrazinoylguanidine was saluretic, without affecting serum potassium or glucose concentrations. The onset of PZG's antihypertensive effect occurred within 4 hours. In contrast, hydrochlorothiazide (HCTZ) increased serum concentrations of urea, triglycerides, and glucose, without affecting cholesterol.

SummaryRenal clearance studies of threonine and phenylalanine in dogs have shown that the maximal rate of tubular re-absorption of these amino acids could not be exceeded by the administration of an amount of each amino acid sufficient to raise the plasma level to a value over 10 times that of the postabsorptive state.

Pyrazinoylguanidine (PZG), 3-aminopyrazinoylguanidine (NH2PZG) and their pyrazinoic acid metabolites were measured by a new reverse-phase HPLC method in the serum of dogs and humans after administration of PZG, NH2PZG or 2-pyrazinoic acid (PZA). Kinetic properties of PZG and its principal metabolite, PZA, were studied in normal humans and also in azotemic patients, since PZG acts on renal tubules of patients with kidney failure to increase urea elimination. In humans and dogs, PZG was rapidly hydrolyzed to PZA. The serum half-life (t1/2) of PZG was 1 h. In turn, PZA was metabolized to 5-hydroxy-PZA, but no evidence appeared for conjugation of PZA with glycine. The apparent volume of distribution of PZG and its 3-amino analog, NH2PZG, exceeded that of total body water. In the dog the serum t1/2 for NH2PZG was twice that of PZG. Compared to PZG, NH2PZG and its metabolite, 3-aminopyrazinoic acid, were much stabler in vitro in serum and water.

This paper reports the effects of extraction time, temperature, flow rate, and pressure on percent extraction, the relative amounts of extract fractions, and their time distribution studied to formulate a qualitative model for the mechanism of supercritical extraction of coal. The solvent used was toluene; the solute was a Wyodak subbituminous coal. Factorial experimental designs and the Yates algorithm were useful in model building.

In patients with azotemia, urea excretion, urea clearance, and urea/creatinine clearance ratio were increased by pyrazinoylguanidine in a dose-related manner. Urine volume and excretion of sodium > chloride > potassium tended to increase during administration of pyrazinoylguanidine. Systemic arterial pressure declined while pyrazinoylguanidine was given at 300 or 600 mg b.i.d. for 3 days. At both doses pyrazinoylguanidine reduced plasma renin activity during the first 2 hours. Between days 1 and 3 only the high dose of pyrazinoylguanidine decreased plasma renin activity and plasma aldosterone levels. These findings with pyrazinoylguanidine are consistent with those of secretion of urea in human subjects across the renal tubules and indicate that this process is susceptible to pharmacologic alteration, even in the presence of severe renal insufficiency. Clinical Pharmacology and Therapeutics (1990) 47, 629–638; doi:10.1038/clpt.1990.84

Eighteen patients with advanced squamous cell carcinoma of the esophagus without prior chemotherapy were treated with carboplatin. Based on experimental data a split dose of carboplatin of 130 mg/m2 g

We previously suggested that the cell fate of the protozoan ciliate, Tetrahymena thermophila, effectively relates to a quorum-sensing mechanism where cell-released factors support cell survival and proliferation. The cells have to be present above a critical initial density in a chemically defined nutrient medium in order to release a sufficient level of these factors to allow a new colony to flourish. At a relatively high rate of metabolism and/or macromolecular synthesis and below this critical density, cells began to die abruptly within 30 min of inoculation, and this death took the form of an explosive disintegration lasting less than 50 milliseconds. The cells died at any location in the culture, and the frequency of cell death was always lower in well-filled vials than those with medium/air interface. Cell death was inhibited by the addition of Actinomycin D or through modifications of the culture conditions either by reducing the oxygen tension or by decreasing the temperature of the growth medium. In addition, plastic caps in well-filled vials release substances, which promote cell survival. The fate of low-density cultures is related to certain ‘physical’ conditions, in addition to the availability of oxygen within closed culture systems.

In superlattice (SL) structures an enhancement of the thermoelectric figure of merit ZT compared to homogeneous materials can be achieved by reduction of the thermal conductivity /spl lambda/. In this context thermoelectric properties of PbTe/ PbSe/sub x/Te/sub 1-x/-SL's, and PbTe(BaF/sub 2/) doping superlattices (SL), and of Bi/sub 2/(Se/sub x/Te/sub 1-x/)/sub 3//Bi/sub 2/(Se/sub y/Te/sub 1-y/)/sub 3/-SL structures are presented. All samples were grown on BaF/sub 2/[111]-substrates by molecular beam epitaxy (MBE). A significant reduction of the in-plane thermal conductivity /spl lambda/ compared to corresponding bulk materials was observed. As the power factors are only slightly reduced, a net increase of the figure of merit ZT can be calculated. The temperature dependence of ZT is discussed.

Bi2Te3 based low dimensional structures are interesting material systems to increase the thermoelectric figure of merit ZT by either the expected reduction of the thermal conductivity or by a possible power factor enhancement due to quantum confinement. Due to low lattice mismatch Bi2(Te1-xSex)3, PbSe1-xTex, as well as Pb1-xSrxTe, and BaF2 are suitable for Bi2Te3 based low dimensional structures. Especially due to their significantly enhanced band gap lead chalcogenide compounds like Pb1-xSrxTe (Pb0.87Sr0.13Te: 0.6 eV) are well-suited barrier materials in MQW structures. Alternatively the insulator BaF2 can be used for that purpose.Here we report mainly on results of different superlattice structures mentioned above grown by molecular beam epitaxy (MBE) on BaF2(111). The structural properties of these layers were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and secondary ion mass spectroscopy (SIMS). Structural performance and thermoelectric properties of different Bi2Te3 based superlattices were reported and compared with regard to their superlattice parameters.

Thermoelectric properties of low dimensional structures based on PbTe/PbSrTe-multiple quantum-well (MQW)-structures with regard to the structural dimensions, doping profiles and levels are presented. Interband transition energies and barrier band-gap are determined from IR-transmission spectra and compared with Kronig-Penney calculations. The influence of the data evaluation method to obtain the 2D power factor will be discussed. The thermoelectrical data of our layers show a more modest enhancement in the power factor σS2 compared with former publications and are in good agreement with calculated data from Broido et al. [5]. The maximum allowed doping level for modulation doped MQW structures is determined. Thermal conductivity measurements show that a ZT enhancement can be achieved by reducing the thermal conductivity due to interface scattering. Additionally promising lead chalcogenide based superlattices for an increased 3D figure of merit are presented.

Multi quantum wells and superlattices are discussed as suitable tools for increasing ZT. Best layer quality should be expected only for lattice matched growth. Therefore [111] barium fluoride should be most suitable compared to other common substrates like mica and sapphire, although up to now epitaxial growth of bismuth telluride on [111] barium fluoride with atomically flatness was not achieved. We present the first bismuth telluride-layers reproducibly prepared on [111] barium fluoride substrates using the molecular beam technique. Three essential factors influence the growth of bismuth telluride on barium fluoride: substrate temperature, the flux ratio of Bi/Te and substrate surface preparation itself even for single crystal [111] barium fluoride substrates. These dependencies of growth characteristics and layer properties are reported. AFM and RHEED analysis show suitable layer by layer growth of bismuth telluride with step height of 1 nm as expected from its crystal structure. Step widths of growth terraces are similar to those known from other MQW-suitable systems like IV-VI-compounds. Further X-ray analysis combined with EDX-analysis (single crystals standard) indicates single phase growth with stable stochiometric composition.

Experimental evidence for an enhancement of the thermoelectric figure of merit ZT in 2D PbTe/Pb/sub 1-x/Eu/sub x/Te multiple-quantum-well (MQW)-structures was recently reported by Harman et al. (1997). To verify these basic concepts MQW-structures based on the Sr-ternary lead chalcogenides Pb/sub 1-x/Sr/sub x/Se and Pb/sub 1-x/Sr/sub x/Te were investigated. PbSe/Pb/sub 1-x/Sr/sub x/Se MQW have been successfully used for lead salt laser diodes. We present properties of bulk Pb/sub 1-x/Sr/sub x/Se and Pb/sub 1-x/Sr/sub x/Te epitaxial films grown by MBE on freshly cleaved BaF/sub 2/(111). N-type films with carrier concentrations between 10/sup 18/ and 10/sup 20/ cm/sup -3/ can be easily obtained by doping with pure bismuth. XRD and AFM measurements show a high structural quality of these films. The surface roughness of PbSrTe is even less than that of PbTe. Temperature dependent measurements of electrical conductivity and thermopower are reported. The thermoelectrical data of bulk PbTe-films agree well with values given by Harman. For MQW-films XRD and AFM analysis indicate high structural perfection. Measurements of transport properties of PbTe/Pb/sub 1-x/Sr/sub x/Te- and PbSe/Pb/sub 1-x/Sr/sub x/Se-MQW structures were evaluated according to Harman and alternatively with stacked well and barrier layers connected in parallel. Both evaluation methods were performed on different types of MQW structures and doping profiles and yield an enhancement in the power factor for a well thickness less than 3 nm. Additionally first thermal conductivity data on IV-VI MQW structures are presented.

(IV-VI)-(V-VI) nanostructures are new systems, which could be used both for the reduction of thermal conductivity and for MQW structures to enhance electrical conductivity. We report on both first steps: IV-VI on V-VI and V-VI on IV-VI growth in the bismuth telluride/lead telluride material system using molecular beam epitaxy. Bismuth telluride layers were grown using element sources, PbTe and PbSe can be grown using the binary compounds. n-PbTe and n-PbSe as well as n-bismuth telluride layers were grown epitaxially on [111]-barium fluoride-substrates. [111]-barium fluoride is probably the best suited substrate for both IV-VI and V-VI-materials due to its small lattice mismatch. The IV-VI-initial-layers were overgrown with n-bismuth telluride, while the V-VI-initial-layers were overgrown with PbTe or PbSe. We report on growth characteristics analysed by AFM, ECP, SEM and SIMS, depending on various growth conditions like substrate temperature and layer thickness. The results taken from as grown samples and after annealing procedures are discussed with respect to the crystal structures accordingly and the ternary phase diagram of bismuth telluride/lead telluride.

Eight hypertensive patients with noninsulin dependent diabetes mellitus (NIDDM) were administered the experimental drug pyrazinoylguanidine (PZG) either alone or in combination with calcium-channel or beta-blockers. This treatment appeared to "downregulate" the glucose fatty acid cycle and reduced both systolic and diastolic blood pressures and mean body weight. Patients served as their own controls in this dose-escalation study, which included placebo treatment (baseline) 3 weeks, 300 mg PZG for 3 weeks and 600 mg for 3 weeks. PZG reduced increased serum concentrations of free fatty acids (FFA), glucose, and triglycerides (TG). TG concentrations correlated inversely with serum HDL-cholesterol concentrations. The beta-blockers used by several patients increased their FFA, glucose, insulin and TG concentrations, as well as blunting their response to PZG. The calcium-channel blockers exerted these effects to a much lesser extent. PZG reduced or abolished glycosuria, related to PZG's capacity to decrease hyperglycemia. Withdrawal of PZG restored glycosuria, as blood sugar increased. PZG was well tolerated. No patient reported any adverse effect or missed a weekly clinic visit (12 weeks). PZG deserves further study as supplementary and/or replacement therapy in NIDDM patients who are hypertensive and hyperlipidemic.

In addition to glomerular filtration and passive back diffusion of urea, there occurs across the renal tubule bidirectional transport of urea inhibitable in one or both directions by specific analogs of pyrazinoylguanidine (PZG). Effect of PZG on the profiles of sodium and urea concentrations along the tubule (stop flow) are consistent with their independent transport. Inhibition of urea and sodium reabsorption by PZG is dose dependent. PZG does not inhibit potassium excretion.

The simultaneous excitation-ionization and excitation-capture processes in collisions of 223 MeV/u He-like uranium ions with heavy target atoms are identified by measuring the x-ray (L ? K) transitions in coincidence with projectiles undergoing charge exchange. The state selective cross sections for the population of the L-shell sub-levels of the projectile are determined, and in the case of excitation-ionization data compared to the detailed relativistic calculations. It is emphasized that the experimental data can serve as an important benchmark of the independent particle approximation and fully relativistic perturbative models, for the domain of relativistic ion-atom collisions.

In einer randomisierten Studie wurden 79 Patienten entweder mit cis-DDP 3 mg/kg i.v. Tag 1 und Bleomycin 15 mg/m2 i.v. kontinuierlich Tag 2–5 (Arm A) oder weniger aggressiv mit Methotrexat

Neutron activation analysis (NAA) is a useful method to determine the concentration of trace elements in biological samples. But it has its special problems and error sources. An extensive study was performed to prove that weight loss affects both accuracy and precision of NAA based on post-irradiation weights. Weight losses of 5 ± 3% and 14 ± 7% (mean ± SD) were observed after irradiating blood and its main components for more than 12 h with thermal neutron fluxes of about 1014n · cm−2 · s−1 in two reactors with different cooling facilities. These losses were flux-dependent, but independent of irradiation time, sample donor, type and size, and post-irradiation time and handling. In order to avoid this NAA-specific error elemental concentrations should be based on pre-irradiation weights.

Two hours after suicidal ingestion of an unknown amount of selenium dioxide, a 17-year-old male was admitted to hospital with asystolia and apnea. Attempts at resuscitation failed and the patient was pronounced dead. Findings at autopsy included congestion of lungs and kidneys, diffuse swelling of the heart, and brain edema. The most impressive finding was an orange-brown discoloration of the skin and all viscera, probably due to hemolysis and/or pigmentation related to ingestion of selenium dioxide. Selenium blood and tissue levels were increased by a factor of 100-1000 as compared to normal. The highest concentrations were found in pancreas, spleen, liver, and adipose tissue. For elucidation of the chemical nature of selenium in tissues, a new analytical method which was based on carbon disulfide extraction was developed. Carbon disulfide is a good solvent for non-polar selenium compounds like elemental selenium and selenium disulfide, but not for polar compounds like selenite and selenoproteins. A major fraction of selenium in tissues was extractable by carbon disulfide, which seems to indicate the presence of elemental selenium and/or selenium disulfide. The color of these substances is red and orange, respectively. This might explain at least part of the discoloration of skin and tissues. In vitro experiments suggested that trace amounts of hydrogen selenide, which is an intermediate of selenite metabolism, probably induced hemolysis. For evaluation of the therapeutic value of hemoperfusion in selenium poisoning in vitro hemoperfusion experiments were performed, which revealed only a moderate effect on selenium blood levels.

Metabolic oxidative profiles of diazepam (I) were obtained by aromatic C-4'-hydroxylation, N-1-demethylation, and 3-hydroxylation using a supernatant of rat liver. Incubation of 3-methyldiazepam (VI), which suppressed 3-hydroxylation, and N-1-nor-3-methyldiazepam (VII), were used to separately investigate these three oxidative pathways. Treatment of animals with phenobarbital enhanced N-1-demethylation and 3-hydroxylation, and to a variable extent C-4'-hydroxylation. Application of metyrapone reduced metabolite formation by 3-hydroxylation and N-1-demethylation, but had no effect on C-4'-hydroxylation. Metyrapone inhibition was more pronounced following than prior to phenobarbital treatment. C-2-hydroxylation was studied using medazepam (XX) incubations. This pathway was increased by phenobarbital pretreatment and reduced by metyrapone inhibition which was again more pronounced following than prior to phenobarbital pretreatment. These results support earlier conclusions on the heterogeneity of liver microsomes and suggests the presence of different species of hepatic microsomal terminal oxidases. Phenobarbital treatment and metyrapone change the metabolic profile via induction and inhibition, respectively, and, thus, in the case of 1,4-benzodiazepines, the formation of metabolites with varying pharmacological activity. This could become important in clinical situations as a diagnostic mean to determine induction under various treatment or, possibly, during cumulation of metabolites with a long half-life.

Based on the two-spin cluster model of spin glass, the magnetization process at low T is investigated. The short-range inter-cluster interaction is taken into account by excitation waves, treated as free Bosons. They feel, however, additionally a Weis-type molecular field of long range. For certain parameter sets in the range T < TF magnetic instabilities are found, as well as metastable branches of m(H, T)-curves, leading to magnetization jumps, induced by external magnetic field. The phase diagram shows a line of first-order transitions and a point of a higher-order transition. Hysteresis and domain patterns are the usual behaviour in this region. Fur ein Zwei-Spin-Cluster-Modell des Spinglases wird der Magnetisierungsprozes fur niedrige T untersucht. Eine kurzreichweitige Inter-Cluster-Wechselwirkung wird mittels Exzitonenwellen behandelt, die als freie Bosonen approximiert werden. Zusatzlich fuhlen diese Exzitonen ein Weissches Molekularfeld, welches eine langreichweitige Cluster—Cluster-Wechselwirkung approximiert. Fur gewisse Parametersatze werden im Bereich T < TF magnetische Instabilitaten und metastabile Zweige der Magnetisierungskurve m(H, T) gefunden. Es entstehen Magnetisierungssprunge, die durch Veranderungen des auseren Magnetfeldes induziert werden. Das Phasendiagramm zeigt eine Linie von Phasenubergangen erster Ordnung und einen Punkt mit einem Ubergang hoherer Ordnung. In diesem Bereiche treten wie ublich Hystereseerscheinungen sowie Domanenstrukturen auf.

A new-type effective field theory with correlations in a diluted ferromagnet is discussed. The critical percolation concentration is obtained analytically. The transition temperatures are given as a universal function of effective number of nearest-neighbours. The specific heat and internal energy are also obtained. Eine neue effektive Feldtheorie mit Berucksichtigung von Korrelationen wird fur einen verdunnten Ferromagneten diskutiert. Es wird die kritische Perkolationskonzentration berechnet. Die Ubergangstemperatur ist gegeben als eine universelle Funktion einer effektiven Zahl von nachsten Nachbarn und die spezifische Warme sowie die innere Energie werden berechnet.

This paper summarizes historical spill statistics and describes techniques and equations that can be used to predict possible future oil spillage from marine tankers, offshore petroleum development facilities, and cross-country pipelines. These techniques would be expected to provide worst-case estimates because they do not account for continuing improvements in technology, operating procedures and safety measures. Information compiled from the literature on world-wide tanker casualty spills during 1969–972 indicates that such spills can be expected to occur within 50 miles of land an average of once in every 1,000 vessel port-calls or about once in every 50 vessel-years of operation. The average size of these casualty spills (within 50 miles of land) is 7,100 bbl and the average spill rate is about 87 bpmb (bbl per million bbl) transported. Oil spill data from the U.S. Geological Survey are presented for outer continental shelf (OCS) petroleum development operations during 1966–1975. This information indicates an average spill rate from all causes (pipeline accidents, blowouts, fires, etc.) of about 72 bpmb produced. Oil industry cross-country pipeline spill data for Western Europe (1968–1974) and Canada (1965–1972) show that 1.1 to 1.5 spills can be expected from all causes per year per 1,000 miles of pipeline. The mean spill rate (obtained for Western Europe only) was 3.6 bpmb of throughput.

Diquat wird durch den stark sauren Kationenaustauscher Permutit R S 40 aus dem Untersuchungsmaterial isoliert und anschlisend mit gesattigter Ammoniumchloridlosung eluiert. Die spektrophotometrische Gehaltsbestimmung erfolgt nach Reduktion der Verbindung zum grun gefarbten Radikal bei 379 nm.

The proper choice of an analyzing crystal sometimes makes It possible to suppress second-order reflections which interfere with X-ray fluorescence analysis. Some of the problems associated with the analysis of small amounts of hafnium in zirconium, using a silicon crystal and a pulse-height analyzer, are discussed.

The recrystallization of gold is investigated by electrical resistivity measurements and checked with photomicographs. The influence of irradiation with 4 Me V α-particles at different temperatures and flux densities is studied. Between 100 to 150°C the recrystallization of Au (purity 99.96%) is enhanced during irradiation. With increasing irradiation dose the enhanced reaction rate is overcompensated by a strong retardation of the grain growth. The enhancement is attributed to radiation-induced diffusion, the retardation to barrier pinning of dislocations, and grain boundaries. Der Verlauf der Rekristallisation von kaltgewalztem Gold wird mit elektrischer Widerstandsmessung und mikroskopischen Gefugeaufnahmen verfolgt. Untersucht wird der Einflus von Bestrahlung mit 4 Me V α-Teilchen bei verschiedenen Temperaturen und Flus-dichten. Bei Bestrahlungstemperaturen von 100 bis 150°C wird (bei Gold von 99,96% Reinheitsgrad) eine Beschleunigung des Reaktionsablaufs beobachtet, die der strahlungsstimulierten Diffusion zugeschrieben wird. Der erhohten Reaktionsgeschwindigkeit wirkt eine mit der Strahlungsdosis rasch zunehmende Behinderung des Kornwaschstums entgegen; diese Beobachtung wird darauf zuruckgefuhrt, das strahlungsbedingte lokalisierte Hindernisse wandernde Versetzungen und Korngrenzen blockieren.

A procedure for obtaining equilibrium data and predicting ideal-stage requirements in a complex liquid-liquid extraction system is presented. Preliminary equilibrium data are obtained from a simulated column run involving a series of batch contacts operated in such a manner as to approach steady state countercurrent conditions. The flow ratios and stage requirements for continuous operation are then estimated by trial-and-error by use of a modified McCabe-Thiele method. The procedure lends itself particularly well to those systems with interdependent distribution of the two components. Data for the separation of hafnium from zirconium are presented to show the utility of the method.

Vergleichende Gangunterschiedsmessungen an Kern und Plasma von primaren Strumazellen erfolgten unter Anwendung des Beleuchtungsspalts bzw. des Beleuchtungsgitters. Der Fehler der Methode war bei Benutzung des Beleuchtungsgitters kleiner als bei Anwendung des Beleuchtungsspaltes. Die Trockenmasse wurde von Plasma und Kern in Hankslosung von pH 6,8, 7,0, 7,2 oder 7,4 bestimmt. Die Trockenmasse lies sich an der gleichen Zelle 7mal im Abstand von 15 min bis zu 90 min Meszeit ermitteln. Es ist zu empfehlen, die Trockenmasse in Hankslosung von pH 6,8 zu bestimmen und die Meszeit auf 60 min zu beschranken. Anderenfalls verandern sich bei pH 6,8 der Hankslosung die Werte fur die Trockenmasse des Kernes bis zu 25%.

The mechanism of solid state polycondensation has been subjected to a fundamental analysis. Equations were formulated for combined diffusion and chemical reaction for two separate situations. One was for solid state polycondensation in polymer flakes or chips. The other dealt with polymer powders. The resultant solutions related molecular weight changes to rate functions. A technique for deriving the rate functions from experimental data is described. Solid state polycondensations were then studied for nylon 66, nylon 6-10, and polyethylene terephthalate. These data which ranged from 120 to 200°C. were tested with various mechanisms. The most appropriate one was found to be that developed in the present work. Chemical reaction was found to be the rate controlling step in solid state polycondensation in nylon 66, polyethylene terephthalate, powders of nylon 6-10 and larger particles of nylon 6-10 at and above 160°C. Diffusion of byproduct through the solid was the rate controlling step for larger particles of nylon 6-10 at temperatures below 160°C. Thermograms of nylon 6-10 indicated morphological changes which possibly influenced the behavior of the larger nylon 6-10 particles. The Arrhenius relation was fitted to the situations where chemical reaction controlled.