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Showing papers by "Technical University of Dortmund published in 1996"


Journal ArticleDOI
TL;DR: In this paper, the authors prove existence and uniqueness of (Bayesian) equilibrium for a class of generally asymmetric all-pay auctions with incomplete information, and relate their uniqueness result to the well-known multiplicity of equilibria in the war of attrition (second-price allpay auction), which emerges as a limit point of the class of two-player auction games considered.

284 citations


Journal ArticleDOI
TL;DR: In this article, the mixing of right-handed heavy Majorana neutrinos creates a CP-asymmetric universe, and when these Majorana Neutrinos subsequently decay more lepton than anti leptons are produced, the asymmetry is finally converted into baryon asymmetry during the electroweak phase transition.

259 citations


Proceedings ArticleDOI
20 May 1996
TL;DR: An overview of the most important representatives of algorithms gleaned from natural evolution, so-called evolutionary algorithms, are presented, with special emphasis on the principle of strategy parameter self-adaptation utilized by the first two algorithms to learn their own strategy parameters such as mutation variances and covariances.
Abstract: We present an overview of the most important representatives of algorithms gleaned from natural evolution, so-called evolutionary algorithms. Evolution strategies, evolutionary programming, and genetic algorithms are summarized, with special emphasis on the principle of strategy parameter self-adaptation utilized by the first two algorithms to learn their own strategy parameters such as mutation variances and covariances. Some experimental results are presented which demonstrate the working principle and robustness of the self-adaptation methods used in evolution strategies and evolutionary programming. General principles of evolutionary algorithms are discussed, and we identify certain properties of natural evolution which might help to improve the problem solving capabilities of evolutionary algorithms even further.

259 citations


Book ChapterDOI
09 Jun 1996
TL;DR: The strengths of the proposed deterministic schedule and the self-adaptation method are demonstrated by a comparison of their performance on difficult combinatorial optimization problems, and both methods are shown to perform significantly better than the canonical genetic algorithm.
Abstract: The role of the mutation rate in canonical genetic algorithms is investigated by comparing a constant setting, a deterministically varying, time-dependent mutation rate schedule, and a self-adaptation mechanism for individual mutation rates following the principle of self-adaptation as used in evolution strategies. The power of the self-adaptation mechanism is illustrated by a time-varying optimization problem, where mutation rates have to adapt continuously in order to follow the optimum. The strengths of the proposed deterministic schedule and the self-adaptation method are demonstrated by a comparison of their performance on difficult combinatorial optimization problems (multiple knapsack, maximum cut and maximum independent set in graphs). Both methods are shown to perform significantly better than the canonical genetic algorithm, and the deterministic schedule yields the best results of all control mechanisms compared.

226 citations


Journal ArticleDOI
TL;DR: A next-to-leading-order QCD analysis of spin asymmetries and structure functions in polarized deep inelastic lepton-nucleon scattering is presented within the framework of the radiative parton model.
Abstract: A next-to-leading-order QCD analysis of spin asymmetries and structure functions in polarized deep inelastic lepton-nucleon scattering is presented within the framework of the radiative parton model. A consistent NLO formulation of the ${\mathit{Q}}^{2}$ evolution of polarized parton distributions yields two sets of plausible NLO spin-dependent parton distributions in the conventional MS factorization scheme. They respect the fundamental positivity constraints down to the low resolution scale ${\mathit{Q}}^{2}$=${\mathrm{\ensuremath{\mu}}}_{\mathrm{NLO}}^{2}$=0.34 ${\mathrm{GeV}}^{2}$. The ${\mathit{Q}}^{2}$ dependence of the spin asymmetries ${\mathit{A}}_{1}^{\mathit{p},\mathit{n},\mathit{d}}$(x,${\mathit{Q}}^{2}$) is similar to the leading-order (LO) one in the range 1\ensuremath{\le}${\mathit{Q}}^{2}$\ensuremath{\le}20 ${\mathrm{GeV}}^{2}$ and is shown to be non-negligible for x values relevant for the analysis of the present data and possibly forthcoming data at DESY HERA. \textcopyright{} 1996 The American Physical Society.

220 citations


Journal ArticleDOI
01 Oct 1996-EPL
TL;DR: In this article, the authors used deuteron NMR to study molecular reorientation rates and rate exchange processes in supercooled ortho-terphenyl, and monitored the re-equilibration of different subensembles through four-time stimulated echo experiments.
Abstract: Using deuteron NMR, we have studied molecular reorientation rates and rate exchange processes in supercooled ortho-terphenyl. We monitor the re-equilibration of differently selected subensembles through four-time stimulated echo experiments. A comparison of the two-time with the four-time echoes suggests that the characteristic time scales for reorientation and dynamical exchange are relatively similar. The four-time correlation functions were described using various multi-state rate exchange models.

195 citations


Journal ArticleDOI
S. Aid1, V. Andreev2, B. Andrieu3, R. D. Appuhn  +413 moreInstitutions (25)
TL;DR: In this paper, a new measurement of the proton structure function F 2 ( x, Q 2 ) is reported for momentum transfers squared Q 2 between ].5 GeV 2 and 5000 GeV2 and for Bjorken x between 3 · 10 −5 and 0.32 using data collected by the HERA experiment H1 in 1994.

192 citations


Journal ArticleDOI
TL;DR: In this paper, the abilities of different species of seaweeds and their derivatives to remove a range of heavy metals from solution under standard laboratory conditions were determined, and the effect of the presence of more than one metal ion in solution was investigated in order to determine whether any competition effects might have affected metal-ion uptake.

149 citations


Book ChapterDOI
22 Feb 1996
TL;DR: Two-independent sequences of random variables; universal hash classes of higher degree (“(c, l)-universal” classes) and l-wise independent random variables, for l ≥ 2; algorithms for static and dynamic perfect hashing with an optimal number of random bits; all using pure integer arithmetic without the need for providing prime numbers of a certain size.
Abstract: Let u, m≥1 be arbitrary integers and let k≥u. The central result of this paper is that the multiset H={itha,b¦0≤a, b

136 citations


Journal ArticleDOI
TL;DR: The plaque optimization can be performed by dosimetric measurements for the individual patient ("dosimetric treatment planning") and the time consumption for this procedure is less than for a physically correct computer-based therapy planning, e.g., by means of a Monte Carlo simulation.
Abstract: We have developed dosemeters based on plastic scintillators for a variety of applications in radiation therapy. The dosemeters consist basically of a tissue‐substituting scintillator probe, an optical fiber light guide, and a photomultiplier tube. The background light generated in the light guide can be compensated by a simultaneous measurement of the light from a blind fiber. Plastic scintillator dosemeters combine several advantageous properties which render them superior to other dosemeter types for many applications: minimal disturbance of the radiation field because of the homogeneous detector volume and the approximate water equivalence; no dependence on temperature and pressure (under standard clinical conditions) and angle of radiation incidence; no high voltage in the probe; high spatial resolution due to small detector volumes; direct reading of absorbed doses; and a large dynamical range. The high spatial resolution together with direct reading make these detectors suitable for real‐time 3‐D dosimetry using multi‐channel detector systems. Such a system has been developed for eye plaque dosimetry and successfully employed for dosimetric treatment optimization. The plaque optimization can be performed by dosimetricmeasurements for the individual patient (‘‘dosimetric treatment planning’’). The time consumption for this procedure is less than for a physically correct computer‐based therapy planning, e.g., by means of a Monte Carlo simulation.

134 citations


Journal ArticleDOI
TL;DR: This work presents an on-line control method that is evaluated in two different physical environments and applied to two tasks—obstacle avoidance and object following—using the Khepera robot platform and shows fast learning and good generalization.
Abstract: We present a novel evolutionary approach to robotic control of a real robot based on genetic programming (GP). Our approach uses GP techniques that manipulate machine code to evolve control programs for robots. This variant of GP has several advantages over a conventional GP system, such as higher speed, lower memory requirements, and better real-time properties. Previous attempts to apply GP in robotics use simulations to evaluate control programs and have difficulties with learning tasks involving a real robot. We present an on-line control method that is evaluated in two different physical environments and applied to two tasks—obstacle avoidance and object following—using the Khepera robot platform. The results show fast learning and good generalization.

Journal ArticleDOI
TL;DR: The allelic background in the German population of the area was evaluated and the GSTT1 null genotype might represent a minor risk factor for human bladder cancer which should be further investigated.
Abstract: Onehundred-and-thirteen patients with cancer of the urinary bladder (cases) were examined with respect to the frequency of null genotypes of the polymorphic glutathione S-transferases GSTM1 and GSTT1. The allelic background in the German population of the area was evaluated by analysing 170 newborns (controls). The frequency of GSTM1 and GSTT1 null genotypes in this population, using methods based upon internal standard controlled polymerase chain reaction (PCR), was 0.54 and 0.18 respectively. An elevated relative bladder cancer risk of GSTM1 null genotype carriers was indicated by comparison of this background with the data of the bladder cancer cases (OR = 1.81; 95% CI [1.10, 2.98]; p = 0.019). The frequencies of the GSTT1 null genotype in the total group of bladder cancer cases versus controls did not differ statistically. However, a significantly higher relative risk of bladder cancer for the GSTT1 null genotype was detected in the cases-subgroup of non-smokers (OR = 3.84; 95% CI [1.21, 12.23]; p = 0.023). Thus, the GSTT1 null genotype might represent a minor risk factor for human bladder cancer which should be further investigated.

Journal ArticleDOI
TL;DR: A newly developed method for the joint analysis of the spectrum and the amplitude of EMGs (JASA) which permits discrimination between fatigue-induced and force-related changes in the EMG confirmed the development of muscular fatigue in the course of urological operations.
Abstract: An electromyographical fatigue analysis was performed in the operating theatre on four surgeons during 14 urological operations in which 'direct endoscopy' (cf. Luttmann et al. 1996, Part I) was applied. Surface electromyograms (EMG) were derived from the m. trapezius on both sides of the body, the right m. deltoideus, and the left m. erector spinae. The surgeons' activities were documented by simultaneously recording an electrical activity code signal parallel to the EMGs. The electrical activity (EA) was formed from the raw EMG by rectification and continuous averaging. For purposes of spectral analysis, the EMGs were digitized and converted to the frequency domain by Fast Fourier Transformation. During the performance of endoscopic surgery, an increase in EA, as well as a spectral shift towards lower frequencies, are observed for at least one of the muscles under test in all of the operations. This indicates the development of muscular fatigue in the course of the operations. The finding is confirmed by applying a newly developed method for the joint analysis of the spectrum and the amplitude of EMGs (JASA) which permits discrimination between fatigue-induced and force-related changes in the EMG. Utilizing this method, the development of fatigue was confirmed for 11 of the 14 operations in the case of the right m. trapezius. The right trapezius muscle therefore constitutes a bottleneck for the performance of the operations. The endurance time was estimated from the increase in EA and compared with the actual duration of the operations. Since both are of the same order of magnitude, it is concluded that the final part of an operation has to be performed when the muscles are already fatigued. Application of the newly available method known as 'monitor endoscopy' (cf. Part I) can lead to a reduction in muscular strain and fatigue. This, in turn, will enable operations to be performed at less risk to the patient.

Journal ArticleDOI
TL;DR: Investigation of the effects of selenium, an integral component of glutathione peroxidase (GPX), on NF-κB activation and reporter gene assays suggest that seenium supplementation may be used to modulate the expression of NF-σB target genes and HIV-1.
Abstract: The eukaryotic transcription factor NF-κB is involved in the inducible expression of various inflammatory genes as well as in HIV-1 replication. Activation of NF-κB is induced by prooxidants and several stimuli eliciting oxidative stress, such as cytokines, lipopolysaccharide, UV irradiation and other mediators. Various antioxidants inhibit NF-κB activation in response to these stimuli. In this study, we have investigated the effects of selenium, an integral component of glutathione peroxidase (GPX), on NF-κB activation. In selenium-deprived Jurkat and ESb-L T lymphocytes, supplementation of selenium led to a substantial increase of GPX activity. Analysis of DNA binding revealed that NF-κB activation in response to TNF was significantly inhibited under these conditions. Likewise, reporter gene assays using luciferase constructs driven by the HIV-1 long terminal repeat showed a dose-dependent inhibition of NF-κB controlled gene expression by selenium. The effects of selenium were specific for NF-κB, since the activity of the transcription factor AP-1 was not suppressed. These data suggest that selenium supplementation may be used to modulate the expression of NF-κB target genes and HIV-1.

Journal ArticleDOI
TL;DR: The class of compounds of ternary nitrides has been nearly ignored for many years, but recently, it has become a rapidly growing field of interest, shown not only by an increasing number of papers especially since 1990, but also by review articles on this topic.
Abstract: The class of compounds of ternary nitrides has been nearly ignored for many years. But recently, it has become a rapidly growing field of interest. This is shown not only by an increasing number of papers especially since 1990, but also by review articles on this topic by Brese and O’Keeffe,1 DiSalvo,2 Schnick,3 and Kniep.4 The first one is a structural encyclopedia of nitrides, azides, and related compounds containing nitrogen and hydrogen, like amides and imides, known up to 1991. The second provides information on some selected compounds, and the third cited review describes the structures and properties of nonmetal nitrides known up to 1993. The last one gives a survey of actually known alkali and alkaline earth nitridometalates depending on their structural features. Most earlier investigations on ternary nitrides with lithium were done by the group of Juza and collaborators resulting in reviews in the 1950s5 and in the 1960s.6 Two additional reviews were made by Lang et al. in 19767 and 1979.8 In comparison to oxides and halides, the number of nitrides known is small. By applying the BornHaber cycle to these compounds the high dissociation energy of nitrogen, and its unfavorable electron affinity may give arguments for the low thermal stability of nitrides of transition metals in high oxidation states. This is expressed by the compositions of the known binary nitrides of the transition metals of group V and VI. Whereas oxides of these elements in their highest oxidation state are well known, only tantalum forms a tantalum(V) nitride Ta3N5. The other five elements do not reach the oxidation state V or VI, respectively, in combination with nitrogen. On the other hand within the group of alkali metals only one binary nitride, Li3N, is known. Li3N and a great number of ternary nitrides with lithium are sensitive to water or moist air. In Rainer Niewa was born in Dortmund, Germany, in 1967. He studied Chemistry at the Universität-Gesamthochschule Essen and the Universität Dortmund where he received his Dr. degree in 1995. His research activities concentrate on the preparation, crystal structures, and properties of transition metal nitrides.

01 Jan 1996
TL;DR: In this article, ein genereller hierarchischer Ansatz zur Visualisierung skalarer Volumendaten entwickelt is presented, which ermoglicht the direkte Visualisiersierung komprimierter Daten, the Beschleunigung des Darstellungsvorgangs and the Extraktion and Hervorhebung der wesentlichen Strukturen.
Abstract: In dieser Arbeit wurde ein genereller hierarchischer Ansatz zur Visualisierung skalarer Volumendaten entwickelt. Dieser ermoglicht die direkte Visualisierung komprimierter Daten, die Beschleunigung des Darstellungsvorgangs und die Extraktion und Hervorhebung der wesentlichen Strukturen. Grundlegende Konzepte der Multiskalenanalyse mittels hierarchischer Basisfunktionen wurden hierzu verwendet und entsprechend den Anforderungen erweitert. Insbesondere resultierte die Arbeit in speziellen Verfahren zur Vorverarbeitung und Darstellung zeitvarianter Datensequenzen. Sowohl fur die Datenanalyse als auch fur die Bildsynthese wurden Parallelisierungskonzepte entworfen und implementiert. Die integrierte Analyse und Darstellung komplexer skalarer Volumendaten wurde durch diese Entwicklungen ermoglicht.

Journal ArticleDOI
TL;DR: A review of total reflection x-ray fluorescence (TXRF) as an effective excitation mode for energy-dispersive xray spectral analysis is presented in this article, where the instrumental conditions of excitation under grazing incidence (ψ < 0.1°) are emphasized and analytical features of powerful detection and simple and reliable quantification are characterized.
Abstract: A review of total reflection x-ray fluorescence (TXRF) as an effective excitation mode for energy-dispersive x-ray spectral analysis is presented. The instrumental conditions of excitation under grazing incidence (ψ < 0.1°) are emphasized and the analytical features of powerful detection and simple and reliable quantification are characterized. The applicability of TXRF to environmental analyses is illustrated by some typical examples. The analysis of pure water samples leads to detection limits at the ppt (ng/l) level. A special matrix separation is only needed for river, sea and waste waters. The analysis of air dust is directly possible with a sampling volume of 1 m 3 and a sampling time of 1 h. Organ tissue can be analysed down to the lower ppm range after freeze-cutting of μm thick sections. Plant material has to be pulverized and digested prior to analysis, e.g. with nitric acid In combination with a chromatographic separation, speciation is made possible for small 0.5 ml fractions, e.g. for vegetable foodstuffs. For all these applications a multi-element determination can be carried out, for about 20-25 elements simultaneously. Simple and reliable quantification is effected by internal standardization. The reliability of the method has been proved by intercomparison tests. Second-generation instruments that are compact and user-friendly are now commercially available.

Journal ArticleDOI
TL;DR: In this article, the efficiency properties of allocations when firms and households are mobile and when local governments provide local public goods and local public factors were analyzed, and it was shown that an efficient allocation is obtained if there is no outflow of land rents to absentee owners.

Journal ArticleDOI
S. Aid1, J. Zsembery2, K. Zuber3, M. zurNedden4  +423 moreInstitutions (28)
TL;DR: In this article, the authors presented results on J/ψ mesons in ep interactions in the H1 experiment at HERA and showed that the cross-section of diffractive Jψ production with proton dissociation is of similar magnitude as the elastic cross-sectional area.

Journal ArticleDOI
TL;DR: The results indicate that OP does not bioaccumulate in rats receiving low oral doses, in agreement with the hypothesis of a rapid first-pass elimination of OP by the liver after oral ingestion, via glucuronidation and sulphation.
Abstract: Only weak oestrogenic activity has been reported for p-alkylphenols compared with the physiological hormone 17β-estradiol. Despite the low potency, there is concern that due to bioaccumulation oestrogenically efficient blood levels could be reached in humans exposed to trace levels of p-alkylphenols. To address these concerns, toxicokinetic studies with p-tert-octylphenol [OP; p-(1,1,3,3-tetramethylbutyl)-phenol] as a model compound have been conducted in male Wistar rats. OP blood concentrations were determined by GC-MS in rats receiving either single oral (gavage) applications of 50 or 200mg OP/kg body wt or a single intravenous injection of 5mg/kg body wt. The OP blood concentration was ∼1970ng/ml immediately after a single intravenous application, decreased rapidly within 30 min, and was no longer detectable 6–8h after application. The curve of blood concentration vs time was used to calculate an elimination half-life of 310min. OP was detected in blood as early as 10min after gavage administration, indicating rapid initial uptake from the gastrointestinal tract; maximal blood levels reached 40 and 130ng/ml after applications of 50 and 200mg/kg, respectively. Using the area under the curve (AUC) of blood concentration vs time, low oral bioavailabilities of 2 and 10% were calculated for the 50 and 200mg/kg groups, respectively. OP toxicokinetics after repeated administration was investigated in male Wistar rats receiving daily gavage administrations of 50 or 200mg OP/kg body wt for 14 consecutive days. Profiles of OP blood concentration vs time determined on day 1 and day 14 were similar, indicating that repeated oral gavage administration did not lead to increased blood concentrations. Another group of rats received OP via drinking water saturated with OP (∼8mg/l, corresponding to a mean daily dose of ∼800μg/kg) over a period of up to 28 days. OP was not detected in any blood sample from animals treated via drinking water (detection limit was 1–5ng/ml blood). OP concentrations were also analysed in tissues obtained from the repeated gavage (14 days) and drinking water groups (14 and 28 days). In the 50mg/kg group, low OP concentrations were detected in fat and liver from some animals at average concentrations of 10 and 7ng/g tissue, respectively. OP was not detected in the other tissues analysed from this group. In the 200mg/kg group, OP was found in all tissues analysed except testes (fat, liver, kidney, muscle, brain and lung had average concentrations of 1285, 87, 71, 43, 9 and 7ng/g tissue, respectively). OP was not detected in tissues of animals receiving OP via drinking water for 14 or 28 days, except in muscle and kidney tissue of one single animal receiving OP for 14 days. Using rat liver fractions it was demonstrated that OP was conjugated via glucuronidation and sulphation in vitro. A Vmax of 11.24 nmol/(min * mg microsomal protein) and a Km of 8.77μmol/l were calculated for enzyme-catalysed OP glucuronidation. For enzyme-catalysed sulphation, a Vmax of 2.85nmol/(minT15*mg protein) and a Km of 11.35μmol/l were calculated. The results indicate that OP does not bioaccumulate in rats receiving low oral doses, in agreement with the hypothesis of a rapid first-pass elimination of OP by the liver after oral ingestion, via glucuronidation and sulphation. Only if these detoxification pathways are saturated may excessive doses lead to bioaccumulation.

Journal ArticleDOI
TL;DR: Commonly used solid and liquid secondary shift standards for lead were studied with high precision as a function of temperature between 295 K and 315 K to establish a clean 207Pb shift scale.

Journal ArticleDOI
TL;DR: In this article, a simple MO theoretical analysis of the metal-metal interaction in homo- and heterodinuclear species is presented, where the degree of the intermetallic bond formation is rationalized.

Journal ArticleDOI
TL;DR: In this paper, the crystal structure of ζ-Fe 2 N was studied by neutron and high resolution synchrotron powder diffraction at room temperature, and the results showed that the structure was orthorhombic.

Journal ArticleDOI
TL;DR: In this paper, the properties of a high resolution lead/scintillating-fibre calorimeter to upgrade the backward region of the H1 detector were studied with electrons in the energy range from 2-60 GeV.
Abstract: The properties of final modules of a high resolution lead/scintillating-fibre calorimeter to upgrade the backward region of the H1 detector were studied with electrons in the energy range from 2–60 GeV. The electromagnetic calorimeter consists of scintillating fibres with a diameter of 0.5 mm embedded in a lead matrix. This small fibre radius, in combination with a lead-to-fibre ratio of 2.27:1, ensures excellent energy resolution which has been measured to be δ/E=7.1%/ E/GeV ⊕ 1.0% . The spatial resolution as a function of energy for impact points at the center of a cell is given by 4.4 mm/ E/GeV + 1.0 mm . The time resolution was found to be better than 0.4 ns.

Journal ArticleDOI
TL;DR: In this article, the compatibility of recent next-to-leading order strange quark distributions with the available dimuon and F2νN data is investigated and final conclusions concerning these distributions afford further analyses of presently available and/or forthcoming neutrino data.

Journal ArticleDOI
TL;DR: Interference seems to be specific to certain secondary tasks and may be related to memory processes (but most likely not to visuo-spatial and verbal memory) or to the organization of sequences, consistent with previous suggestions.
Abstract: With a repeated sequence of stimuli, performance in a serial reaction-time task improves more than with a random sequence. The difference has been taken as a measure of implicit sequence learning. Implicit sequence learning is impaired when a secondary task is added to the serial RT task. In the first experiment, secondary-task effects on different types of sequences were studied to test the hypothesis that the learning of unique sequences (where each sequence element has a unique relation to the following one) is not impaired by the secondary task, while the learning of ambiguous sequences is. The sequences were random up to a certain order of sequential dependencies, where they became deterministic. Contrary to the hypothesis, secondary-task effects on the learning of unique sequences were as strong or stronger than such effects on the learning of ambiguous sequences. In the second experiment a hybrid sequence (with unique as well as ambiguous transitions) was used with different secondary tasks. A visuo-spatial and a verbal memory task did not interfere with the learning of the sequence, but interference was observed with an auditory go/no-go task in which high- and low-pitched tones were presented after each manual response and a foot pedal had to be pressed in response to high-pitched tones. Thus, interference seems to be specific to certain secondary tasks and may be related to memory processes (but most likely not to visuo-spatial and verbal memory) or to the organization of sequences, consistent with previous suggestions.

Journal ArticleDOI
TL;DR: Ion exchange membranes can function as solid polymer electrolytes (spe) in nonconductive liquids and therefore electro-organic syntheses are possible without supporting electrolytes as discussed by the authors, which can reduce the process steps for separating and recycling of supporting electrolyte and also side reactions with such electrolytes are impossible.

Journal ArticleDOI
TL;DR: In this paper, the structure of bispurine complexes of trans-a2PtII, trans-[(NH3) 2Pt(9-MeA-N7)](NO3)2·H2O (1b) and trans-[NH3] 2pt( 9-MeN7)2](ClO4)2 ·H2 O (3c) has been determined by X-ray crystallography.
Abstract: Mononuclear bis(purine) complexes of trans-a2PtII, trans-[(NH3)2Pt(9-MeA-N7) (9-MeGH-N7)](NO3)2·H2O (1b) and trans-[(NH3)2Pt(9-MeA-N7)2](ClO4)2·H2O (3c), have been prepared and their structures determined by X-ray crystallography. 1b: Space group P1, a = 7.245 (5) A, b = 7.715(6) A, c = 10.907(8) A, α = 82.36(6)°, β = 86.62(6)°, γ = 70.15(6)°, V = 568.3(7) A3, Z = 1. 3c: Space group P21/c, a = 8.312(2) A, b = 15.386(3) A, c = 12.365(2) A, β = 94.83(3)°, V = 1575.72(55) A, Z = 2. The cation of 3c is centrosymmetric. In the cation of 1b, the two purines adopt a head−head orientation with an intramolecular H bond of 2.94(3) A between the exocyclic amino group of 9-MeA and the exocyclic carbonyl group of 9-MeGH. Di- and trinuclear derivatives of 1b and 3c have been synthesized and/or studied in solution. They include compounds of types Cl•N1-A-N7•GH (2a), T•N1-A-N7•GH (2b), GH•N1-A-N7•T (2c), and GH•N7-A-N1•N1-A-N7•GH (2d) as well as X•N1-A-N7•N7-A-N1•X (X = Cl (4), GH (5a), T (5b)) with • representing tran...

Journal ArticleDOI
TL;DR: This study shows no increased prevalence of slow acetylators among urothelial cancer patients in comparison with the normal population, however, in subgroups of cases with a likelihood of past occupational contacts with aromatic amines, there was a trend towards a higher representation of slowacetylators.
Abstract: Objectives The study was designed to realize possible shifts in the ratio of slow to fast acetylators within a group of 196 urothelial cancer patients in an area with earlier benzine production. Methods The subjects were interviewed for occupational and nonoccupational risk factors. The patients were phenotyped for N-acetyltransferase 2 (NAT2) by Grant's caffeine test. A subgroup of 54 patients was additionally genotyped for NAT2. Results The antimode in the NAT2 phenotyping with the caffeine test (AFMU:1X ratio) was 1.0, as evidenced by additional genotyping of the subgroup of 54 patients. The prevalence of slow acetylators in the entire group of bladder cancer patients was 55%, in accordance with published figures for European populations. In a subgroup of 40 patients with occupational histories as workers in chemical or rubber industries 65% were slow acetylators. In a further subgroup of 28 cases having specifically worked at chemical production sites of the local chemical industry, 68% were slow acetylators. Conclusions In contrast to earlier studies, this study shows no increased prevalence of slow acetylators among urothelial cancer patients in comparison with the normal population. However, in subgroups of cases with a likelihood of past occupational contacts with aromatic amines, there was a trend towards a higher representation of slow acetylators. This finding is in accordance with observations of others that the percentage of slow acetylators in urothelial cancer patients is generally decreasing, possibly because the production of benzidine and benzidine-based dyes ceased in the early 1970s.

Journal ArticleDOI
TL;DR: A construction of an inflation rule based on then-fold symmetry Dn for everyn greater than 3 and not divisible by 3, based on the system of tangents of the well-known deltoidD, which form angles with the ζ-axis of typevπ/n.
Abstract: In analogy to the well-known tilings of the euclidean plane $$\mathbb{E}^2 $$ by Penrose rhombs (or, to be more precise, to the equivalent tilings by Robinson triangles) we give a construction of an inflation rule based on then-fold symmetryD nfor everyn greater than 3 and not divisible by 3. For givenn the inflation factor η can be any quotient $$\mu _{n,k} : = \sin \left( {k\pi /n} \right)/\sin \left( {\pi /n} \right)$$ as well as any product $$\prod {_{k = 2}^{n/2} \mu _{n,k}^{ak} ,} $$ where $$\alpha _2 ,\alpha _3 ,..., \in \mathbb{N} \cup \left\{ 0 \right\}$$ . The construction is based on the system ofn tangents of the well-known deltoidD, which form angles with the ζ-axis of typevπ/n. None of these tilings permits two linearly independent translations. We conjecture that they have no period at all. For some of them the Fourier transform contains a ℤ-module of Dirac deltas.