Showing papers by "University of Duisburg-Essen published in 1998"

Supporting visual and verbal learning preferences in a second language multimedia learning environment

Abstract: Erfurt University of Education English-speaking college students who were enrolled in a German course read a 762-word German language story presented by a computer program. For key words in the story, students could choose to see a translation on the screen in English (i.e., verbal annotation) or view a picture or video clip representing the word (i.e,, visual annotation), or both. Students remembered word translations better when they had selected both visual and verbal annotations during learning than only 1 or no annotation; students comprehended the story better when they had the opportunity to receive their preferred mode of annotation. Results are consistent with a generative theory of multimedia learning that assumes that learners actively select relevant verbal and visual information, organize the information into coherent mental representations, and integrate these newly constructed visual and verbal representations with one another. Current developments in information technologies have resulted in rapid advances in the application of instructional and educational technology. There seem to be, however, only small advances in corresponding basic research on the psychological principles of human learning in a multimedia learning environment (Kozma, 1991). This article deals with two of these psychological principles. On the one hand, multimedia learning requires the learner to process information presented in different modes (e.g., in a verbal and a visual mode). Thus, cognitive psychological theories on processing information such as Mayer's (1997) generative theory of multimedia learning are relevant. On the other hand, the term

Autologous Human Monocyte-Derived Dendritic Cells Genetically Modified to Express Melanoma Antigens Elicit Primary Cytotoxic T Cell Responses In Vitro: Enhancement by Cotransfection of Genes Encoding the Th1-Biasing Cytokines IL-12 and IFN-α

Abstract: DNA-based immunization strategies designed to elicit cellular antitumor immunity offer an attractive alternative to protein- or peptide-based approaches. In the present study we have evaluated the feasibility of DNA vaccination for the induction of CTL reactivity to five different melanoma Ags in vitro. Cultured, monocyte-derived dendritic cells (DC) were transiently transfected with plasmid DNA encoding human MART-1/Melan-A, pMel-17/gp100, tyrosinase, MAGE-1, or MAGE-3 by particle bombardment and used to stimulate autologous PBMC responder T cells. CTL reactivity to these previously identified melanoma Ags was reproducibly generated after two or three stimulations with genetically modified DC. Co-ordinate transfection of two melanoma Ag cDNAs into DC promoted CTL responders capable of recognizing epitopes from both gene products. Coinsertion of genes encoding the Th1-biasing cytokines IL-12 or IFN-alpha consistently enhanced the magnitude of the resulting Ag-specific CTL reactivity. Importantly, DC transfected with a single melanoma Ag cDNA were capable of stimulating Ag-specific CTL reactivity restricted by multiple host MHC alleles, some of which had not been previously identified. These results support the inherent strengths of gene-based vaccine approaches that do not require prior knowledge of responder MHC haplotypes or of relevant MHC-restricted peptide epitopes. Given previous observations of in situ tumor HLA allele-loss variants, DC gene vaccine strategies may elicit a greater diversity of host therapeutic immunity, thereby enhancing the clinical utility and success of such approaches.

Identification and characterization of autoreactive T cell responses to bullous pemphigoid antigen 2 in patients and healthy controls.

Abstract: Antibodies against the extracellular domain of bullous pemphigoid antigen 2 (BPAG2) are thought to play a key role in the pathogenesis of bullous pemphigoid (BP), the most frequent autoimmune bullous disease of the skin. Autoreactive T cell responses to BPAG2 were investigated in 16 BP patients and 24 healthy controls by coculture of PBMC with two recombinant BPAG2 proteins (extracellular domain of BPAG2). Primary in vitro T cell responses to BPAG2 were observed in 10/12 BP patients expressing the BP-associated HLA-DQB1*0301 allele and 8/10 DQB1*0301 positive healthy individuals. DQB1*0301 also restricted three autoreactive T cell lines from two BP patients and a healthy donor. In contrast, PBMC from 14 normal patients carrying HLA class II alleles other than DQB1*0301 were not stimulated by BPAG2. Autoreactive BPAG2-specific CD4(+) T cell lines and clones from five BP patients produced both Th1 and Th2 cytokines, whereas three autoreactive T cell lines from three DQB1*0301 positive normal patients produced exclusively IFN-gamma. The absence of BPAG2-specific Th2 cells in healthy individuals strongly suggests that autoreactive Th2 responses to BPAG2 are restricted to BP patients and may thus be critical in the pathogenesis of BP.

Fault diagnostics and fault tolerant control

Abstract: A novel simultaneous fault detection and diagnostics (FDD) and fault tolerant control (FTC) strategy for nonlinear stochastic systems in closed loops based on a continuous stirred tank reactor (CSTR) is presented. The purpose of control is to track the reactant concentration setpoint. Instead of output feedback we propose here to use proportional-integral-derivative (PID) state feedback, which is shown essential to achieve FTC against sensor faults. A new concept of "equivalent bias" is proposed to model the sensor faults. Both the states and the equivalent bias are on-line estimated by a pseudo separate-bias estimation algorithm. The estimated equivalent bias is then evaluated via a modified Bayes' classification based algorithm to detect and diagnose the sensor faults. Many kinds of sensor faults are tested by Monte Carlo simulations, which demonstrate that the proposed strategy has definite fault tolerant ability against sensor faults, moreover the sensor faults can be on-line detected, isolated, and estimated simultaneously.

Influence of protective isolation on outcome of allogeneic bone marrow transplantation for leukemia.

Abstract: Various isolation strategies are used to prevent infections during bone marrow transplantation; data on their efficacy are lacking. We studied whether use of high efficiency particulate air filtration (HEPA) and/or laminar airflow (LAF) units affect transplant-related mortality (TRM) or survival in the first year after allogeneic transplantation. 5065 patients with leukemia receiving bone marrow transplants from an HLA identical sibling (n = 3982) or alternative related or unrelated donors (n = 1083) between 1988 and 1992 were reported to the International Bone Marrow Transplant Registry by 222 teams. Two types of isolation were considered: (1) conventional protective isolation with single patient room and any combination of hand-washing, gloves, mask and gown; and (2) HEPA and/or LAF. Cox proportional hazards regression models were used to determine the relative risks (RRs) of transplant-related mortality (TRM) and of deaths from any cause in patients treated in HEPA/LAF units compared to patients treated in conventional isolation. HLA-identical sibling and alternative donor transplants were analyzed separately. Risks of TRM and overall mortality in the first 100 days post-transplant were significantly lower among patients treated in HEPA/LAF units than in those treated conventionally. RRs of TRM were 0.76 (P = 0.009) for recipients of HLA-identical sibling transplants and 0.65 (P = 0.003) for recipients of alternative donor transplants. Correspondingly RRs of overall mortality were 0.80 (P = 0.02) and 0.65 (P = 0.0006). Decreased risks of TRM and of death in the first 100 days post-transplant resulted in significantly higher 1-year survival rates in patients treated in HEPA/LAF rather than in conventional isolation units. Use of HEPA and/or LAF to prevent infections decreases TRM and increases survival after allogeneic bone marrow transplants for leukemia.

A systematic comparison between on-line and off-line methods for signature verification with hidden Markov models

Abstract: This paper presents an extensive investigation of various HMM-based techniques for signature verification Different feature extraction methods and HMM topologies are compared in order to obtain an optimized high performance signature verification system. Furthermore, this paper may be the first systematic comparison of online and off-line methods for signature verification using exactly the same database, and leading to the surprising result that the difference in performance for both approaches is relatively small.

Detection of CBFbeta/MYH11 fusion transcripts in patients with inv(16) acute myeloid leukemia after allogeneic bone marrow or peripheral blood progenitor cell transplantation.

Abstract: We evaluated the occurrence of the CBFβ/MYH11 fusion transcripts by PCR analysis in 10 patients with inv(16)(p13;q22) acute myeloid leukemia (AML) who underwent allogeneic bone marrow transplantation (BMT) (n = 5), peripheral blood progenitor cell transplantation (PBPCT) (n = 3), or autologous transplantation (n = 2). In addition to the analysis of minimal residual disease (MRD), the chimerism status of patients after allogeneic transplant was studied by PCR. The CBFβ/MYH11 fusion trancript was not detectable in six of seven patients who remained in remission after allogeneic BMT or PBPCT. Two of these patients in remission were monitored for 50 months and 64 months post-BMT. One patient in remission was PCR-positive for CBFβ3 months post-BMT in a single BM sample, but not in a simultaneously examined blood sample, suggesting that analyses from BM samples are more sensitive than those from blood samples. Sequential PCR assays performed 6 and 12 months post-BMT obtained from the same patient were negative. Another patient with a positive PCR assay 3 months post-allogeneic PBPCT, remained PCR positive for the CBFβ/MYH11 fusion transcript when tested 6 months post-PBPCT. A chimerism analysis by PCR revealed a mixed chimerism status in this patient. He relapsed 7 months post-transplant. Before transplant, in all nine patients who were in complete remission of AML (eight patients in 1CR, one patient in 2CR), the CBFβ/MYH11 transcript was detectable. In one patient in relapse, the fusion transcript was not only detectable in blood and bone marrow, but also in a cerebrospinal fluid sample prior to transplant. Two patients who received autologous BMT were monitored for CBFβ/MYH11 transcripts 3 months after BMT. The CBFβ/MYH11 was detected in these patients. Both patients subsequently relapsed 3 months and 23 months post-autologous BMT. The results study show that analysis of the CBFβ/MYH11 fusion transcript by PCR seems to be a suitable method for monitoring minimal residual disease in AML patients with inv (16).

Laminin α2 chain-deficient congenital muscular dystrophy Variable epitope expression in severe and mild cases

Abstract: Objective: To characterize the expression of distinct fragments of laminin α2 chain in patients with partial laminin α2 chain deficiency and variable clinical severity. Background: Deficiency of laminin α2 chain caused by mutations of the LAMA2 gene on chromosome 6q2 account for approximately 50% of cases of congenital muscular dystrophy (CMD) in white patients. The complete absence of laminin α2 is usually associated with a severe phenotype affecting skeletal muscle and the peripheral and central nervous systems. Methods: Quantitative assessment of immunofluorescence to study the expression of C- and N-terminal portions of laminin α2 chain in five patients with partial laminin α2 chain deficiency and variable phenotype. All five patients showed abnormal T2 signal on brain MRI. Results: Immunohistochemistry of muscle specimens showed preserved or minimally reduced expression of the C-terminal region of the laminin α2 chain (67 to 74%), but a marked reduction of the N-terminal region in four patients (13 to 19%). One patient with a mild phenotype had a partial reduction (45%) of the C-terminal and the N-terminal (51%) portions of the laminin α2 chain. Two patients were unable to walk or sit, although the C-terminal portion of the laminin α2 chain was expressed at significant levels (67 to 74%). In contrast, two patients with a similar expression of the C-terminus (67 to 70%) had a milder phenotype and became ambulatory. It was impossible to predict the phenotypes in these four patients with a strong expression of the C-terminus and with low levels of the N-terminus based on the amount of protein expressed. In addition, the laminin β2 chain was moderately reduced (54 to 75%) in all patients with laminin α2 chain deficiency. A strong correlation between the amount of the C-terminus but not for the N-terminus and laminin β2 reduction could be observed. Conclusions: N-terminal antibodies to the laminin α2 chain provide a more precise immunohistochemical detection of partially laminin α2 chain-deficient CMD. The secondary reduction of laminin β2 chain may better define laminin α2 chain-deficient CMD. More data are needed to predict which portions of C-terminus and midrod region of the laminin α2 chain result in a semifunctional protein and a milder phenotype.

Adaptive augmented state feedback control for an experimental planar two-link flexible manipulator

Abstract: An adaptive augmented state feedback control (AASFC) approach is presented for the two-link flexible manipulator, the Duisburg flexible manipulator 01 (DFM01). In order to describe the DFM01 accurately, two disturbance variables are introduced as augmented states. The controller design is based on the steady-state LQR technique in conjunction with an adaptive compensator, where all states are adaptively estimated by employing the strong tracking filter. This control strategy has been tested on DFM01 for both point-to-point and tracking control of the end-effector with different tip mass. Experimental results show that the controller is quite satisfactory, and has strong robustness against payload variations.

Alternative Strategies of Opiate Detoxification: Evaluation of the So-called Ultra-Rapid Detoxification

Abstract: This study was done in order to examine the hypothesis that so-called ultra-rapid opiate detoxification provides a mild, short, and safe withdrawal. A total of 22 patients who were addicted to opiates exclusively underwent ultra-rapid detoxification. Each patient was pretreated with methadone. During general anesthesia lasting about six hours with methohexital or propofol, naloxone was administered with doubling of the dose every 15 minutes with a starting bolus dose of 0.4 mg. The total bolus dose of 12.4 mg, delivered within 60 minutes, was followed by a naloxone infusion of 0.8 mg/h until the next morning. On the day of anesthesia naltrexone (50 mg/d) treatment was initiated. When withdrawal symptoms occurred, specific medications, e.g., clonidine, were added. After determining baseline values, withdrawal symptoms were investigated during a further four weeks by means of established clinical scales. The results document marked withdrawal symptoms for at least one week after detoxification. The intensity of withdrawal symptoms during the first seven days of treatment was significantly (p<0.05) more marked than during baseline. None of the patients underwent a life-threatening complication and only one patient failed to complete the detoxification procedure. Finally, about 75% of the patients could be referred for further treatment. In this study ultra-rapid detoxification provided a safe withdrawal procedure with high rates of completed withdrawals and referrals for further treatment, respectively. However, in contrast to previous reports, many patients suffered from middle-grade withdrawal symptoms over several days. Due to the risks of general anesthesia and the expense associated with this treatment, only patients addicted to opiates alone and for whom other detoxification strategies are unsuitable should undergo a ultra-rapid detoxification procedure.

The Koszul property in affine semigroup rings

Abstract: We investigate the Koszul property for quotients of ane semigroup rings by semigroup ideals. Using a combinatorial and topological interpretation for the Koszul property in this context, we recover known results asserting that certain of these rings are Koszul. In the process, we prove a stronger fact, suggesting a more general denition of Koszul rings, al

Silsesquioxanes as Ligands for Gold Clusters

Abstract: A new type of gold cluster has been synthesized using the silsesquioxane derivative (cyclopentyl)7Si8O12(CH2)3SH (T8-OSS−SH) to exchange the PPh3 ligands in (PPh3)12Au55Cl6 by T8-OSS−SH quantitatively. This exchange causes several important changes in the physical and chemical behavior of the compound. Owing to the presence of cyclopentyl substituents, the cluster becomes soluble in non-polar solvents such as pentane. The stability of this compound compared with that of the PPh3-protected cluster is considerably higher meaning that decomposition in solution, and even under the high-energetic irradiation in the microscope, is not observed over longer periods of time. The increase in the total diameter from 2.1 to ca. 4.4 nm is probably responsible for these advantageous properties, supported by strong S−Au bonds. The increase in size is also expressed as an increase in the activation energy for electron-tunneling processes through the ligand shells of neighboring clusters in a densely packed pellet. This increase is from 0.16 eV for (PPh3)12Au55Cl6 to 0.26 eV for the T8-OSS−SH-protected cluster.

An unsupervised texture segmentation algorithm with feature space reduction and knowledge feedback

Abstract: This paper presents an unsupervised texture segmentation algorithm based on feature extraction using multichannel Gabor filtering. It is shown that feature contrast, a criterion derived for Gabor filter parameter selection, is well suited for feature coordinate weighting in order to reduce the feature space dimension. The central idea of the proposed segmentation algorithm is to decompose the actual segmented image into disjunct areas called scrap images and use them after lowpass filtering as additional features for repeated k-means clustering and minimum distance classification. This yields a classification of texture regions with an improved degree of homogeneity while preserving precise texture boundaries.

Alumina membranes — templates for novel nanocomposites

Abstract: Three different examples have shown that nanoporous alumina membranes serve as ideal templates for the formation of nanostructured materials and also as a support of those materials in composites. The unique properties of such membranes (transparency, chemical resistivity, thermal stability, adjustable pore sizes etc.) and the very simple mode of generating these composites are the benefits of using this inorganic template material.

Fast repair of O6-ethylguanine, but not O6-methylguanine, in transcribed genes prevents mutation of H-ras in rat mammary tumorigenesis induced by ethylnitrosourea in place of methylnitrosourea.

Abstract: Differential repair of structurally distinct mutagenic lesions in critical genes may influence the cellular risk of malignant conversion We have investigated rat mammary tumorigenesis induced by N-ethyl-N-nitrosourea (EtNU) versus N-methyl-N-nitrosourea (MeNU) with respect to tumor incidence, ras gene mutation, and gene-specific repair Both carcinogens induced mammary adenocarcinomas at high yield In mammary epithelia (very low expression of O6-alkylguanine-DNA alkyltransferase, MGMT), O6-methylguanine (O6-MeGua) was eliminated from transcribed (H-ras and β-actin) and inactive genes (IgE heavy chain) at the same slow rate as determined for bulk genomic DNA The persistence of O6-MeGua in DNA correlated with a high frequency of G:C → A:T transition mutations at codon 12 of the H-ras gene in MeNU-induced tumors Repair of O6-ethylguanine (O6-EtGua), too, was slow in the IgE heavy chain gene as in bulk DNA Contrasting with O6-MeGua, however, O6-EtGua was removed ≈20 times faster from the active H-ras and β-actin genes via MGMT-independent mechanism(s) Accordingly, no H-ras codon 12 mutations were found in EtNU-induced tumors, and 5- to 8-fold surplus alkyltransferase activity of the mammary epithelia—via a bacterial ada transgene—did not significantly counteract tumorigenesis in EtNU-exposed contrary to MeNU-treated animals Neither MeNU- nor EtNU-induced tumors exhibited mutations at codons 13 and 61 of H-ras or codons 12, 13, and 61 of K-ras Fast repair of O6-EtGua, but not O6-MeGua, in transcribed genes thus prevents mutational activation of H-ras when rat mammary carcinogenesis is initiated by EtNU in place of MeNU

Identification of a silencing element in the human 15q11-q13 imprinting center by using transgenic Drosophila

Abstract: Prader–Willi syndrome (PWS) and Angelman syndrome are neurogenetic disorders caused by the lack of a paternal or a maternal contribution from human chromosome 15q11-q13, respectively. Deletions in the transcription unit of the imprinted SNRPN gene have been found in patients who have PWS or Angelman syndrome because of a parental imprint switch failure in this chromosomal domain. It has been suggested that the SNRPN exon 1 region, which is deleted in the PWS patients, contains an imprint switch element from which the maternal and paternal epigenotypes of the 15q11-q13 domain originate. Using the model organism Drosophila, we show here that a fragment from this region can function as a silencer in transgenic flies. Repression was detected specifically from this element and could not be observed with control human sequences. Additional experiments allowed the delineation of the silencer to a fragment of 215 bp containing the SNRPN promoter region. These results provide an additional link between genomic imprinting and an evolutionary conserved silencing mechanism. We suggest that the identified element participates in the long range regulation of the imprinted 15q11-q13 domain or locally represses SNRPN expression from the maternal allele.

A new degree bound for vector invariants of symmetric groups

Abstract: Let R be a commutative ring, V a finitely generated free Rmodule and G < GLR(V) a finite group acting naturally on the graded symmetric algebra A = S(V). Let ^g(V, G) denote the minirnal number m, such lxhat the ring AG of invariants can be generated by finitely many elements of degree at most m. For G = En and V(n, kn), the k-fold direct sum of the natural perrnutation module, one knows that p(V(n, kn), En) < n, provided that n! is invertible in R. This was used by E. Noether to prove p(V, G) < IGI if IGl! G A*. In this paper we prove p(V(n, 1z), En) < masc{n, kn(n-1)} for arbitrary commutative rings R and show equality for n = ps a prime power and A= z or any ring with n 1R = O. Ou:r results imply ^g(V, G) < maz{lGl, rank(V)(lGI-1)} for any ring with IGI G R*.

Influence of temperature on the depinning transition of driven interfaces

Abstract: We study the dynamics of a driven interface in a two-dimensional random-field Ising model close to the depinning transition at small but finite temperatures T using Glauber dynamics. A square lattice is considered with an interface initially in the (11)-direction. The drift velocity v is analyzed using finite-size scaling at T = 0 and additionally finite-temperature scaling close to the depinning transition. In both cases a perfect data collapse is obtained from which we deduce β ≈ 1/3 for the exponent which determines the dependence of v on the driving field, ν ≈ 1 for the exponent of the correlation length and δ ≈ 5 for the exponent which determines the dependence of v on T.

Postural responses to changing task conditions in patients with cerebellar lesions

Abstract: OBJECTIVE To investigate the role of the cerebellum in postural adaptation for changes to the stimulus type of support surface displacements (backward translations v “toes up” rotations). METHODS A group of 13 patients with chronic, isolated lesions of the cerebellum and 15 control subjects were tested. Automatic postural responses of the medial gastrocnemius and anterior tibial muscles were recorded. The first paradigm consisted of 10 rotational perturbations followed by 10 backward translations of the platform, and 10 backward translations followed by 10 rotations. The second paradigm consisted of 18 rotations and two randomly interposed translational perturbations, and 18 translations with two rotations randomly interposed. RESULTS When the type of perturbation changed from an expected translation to an unexpected rotation and vice versa both control subjects and cerebellar patients showed an immediate and significant change in the response amplitude of the medial gastrocnemius and at the same time an immediate and significant change in the response amplitude of the anterior tibial muscles. Neither controls nor cerebellar patients showed effects of prediction in surface displacements of unexpected types of perturbation. Both controls and cerebellar patients showed no gradual increase in the gastrocnemius response in subsequent trials of surface translations following a block of 10 surface rotations and no gradual increase in the response amplitude of the anterior tibial muscle in subsequent trials of surface rotations following a block of 10 surface translations. CONCLUSIONS Despite postural hypermetria, the integrity of the cerebellum does not seem critical for adaptation of postural synergies to changing stimulus types of surface displacements. The present results support previous findings suggesting that the main role of the cerebellum in automatic postural responses may be gain control.

Megalencephaly, mega corpus callosum, and complete lack of motor development: A previously undescribed syndrome

Abstract: We report on 3 sporadic cases of in utero onset megalencephaly. Children were born to healthy nonconsanguineous parents after uneventful pregnancies. Head circumferences were just above the 97th centile at birth in 2 patients, 2 cm above the 97th centile in 1 patient, and subsequently increased to 4.5-6.5 cm above the 97th centile at age 5 years. All patients completely lacked motor and speech development and showed very little intellectual progress. There was a distinctive facial aspect with frontal bossing, low nose bridge, and large eyes, but no cutaneous abnormalities and no signs of other organ involvement. Magnetic resonance imaging showed bilateral megalencephaly with a broad corpus callosum, enlarged white matter, and focally thick gray matter, resulting in pachygyric appearance of the cortex. Opercularization was incomplete, and the Sylvian fissures were wide. Somatosensory evoked potentials in 1 patient showed normal latencies of cervical and contracortical potentials but bilaterally increased cortical amplitudes. To the best of our knowledge, no similar case observations have been recorded previously.

SKILL - A Scalable Internet-Based Teaching and Learning System.

Abstract: This paper describes the architecture of a scalable Internet-based teaching and learning system (SKILL) currently developed at the University of Essen, Germany. The system will be developed first with the focus to the department Information Systems and Software Technologies, but is designed as a scalable architecture for a much wider scope. The primary objective of SKILL is to provide students a collaborative and adaptive learning environment utilising new web technologies proposed by W3C. Basic components of SKILL are (a) course material based on concepts which are organised in an ordinal rating derived from pre-requirements (b) annotation facility suited for collaboration work and (c) configuration environment for tailoring the system.

Bis(bis(trimethylsilyl)methyl)tin(IV) Chalcogenides as Possible Precursors for the Metal Organic Chemical Vapor Deposition of Tin(II) Selenide and Tin(II) Telluride Films

Abstract: Two air- and light-stable compounds, bis(bis(trimethylsilyl)methyl)tin(IV) selenide and telluride, [Sn{(SiMe3)2CH}2(μ-E)]2 (E = Se (1) and Te (2)), were investigated as possible precursors for metal organic chemical vapor deposition (MOCVD). Their sublimation rate was measured by thermal gravimetric analysis in the 190−260 °C range and was found to be as high as 2 mg/min at 260 °C at 14 mbar. MOCVD experiments were conducted using both compounds as precursors at 300−600 °C and 1 Torr under a flow of a 1:1 He/H2 mixture. Strong selectivity of the decomposition reaction was found toward the metallic surfaces (copper, silver, gold) with respect to nonmetallic surfaces (quartz, silicon with natural oxide layer). A thin layer (≈10 nm) of conducting seeding layer was used for the deposition of carbon-free film of SnTe, using 2 as a precursor. The films were examined by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analyses.

Modelling secure and fair electronic commerce

Abstract: Security and fairness in business transactions are basic requirements demanded by any participant in electronic markets. We propose COPS as an infrastructure for building adaptable electronic markets with main focus on security and fairness and MOSS as a methodology for analysing and modelling the security semantics of business transactions. Both are necessary to control the risks involved in dealing (trading) with untrusted parties in an open electronic commerce environment. We address the phases information, negotiation and execution of a business transaction and discuss security requirements which in the past were recognised as being very important for electronic market participants but had only received limited or little attention in the electronic commerce research community.

Regulation of gap junction connexins in the endometrium during early pregnancy

Abstract: In mammalian species embryo implantation into uterine tissue is restricted to a limited time period, the receptive phase. For successful implantation appropriate differentiation of the receptive endometrium is under the control of ovarian steroid hormones. In addition, locally acting embryonic signals are needed to modulate the maternal environment before invasion of the trophoblast is permitted. The expression pattern of gap junction channel proteins, connexins (cx), is directly related to this process. In rodents as well as in rabbit and humans the receptive endometrium is characterized by a lack of such cell-to-cell communication channels. In the rat endometrium cx26 is suppressed in the epithelium and cx43 in the stromal compartment by maternal progesterone, a phenomenon that can be observed similarly in human endometrium. Experimental approaches revealed that both connexin genes react very sensitively to progesterone and estrogen treatment. In rat and rabbit connexin expression is induced locally in the endometrium in response to the implanting blastocyst. In both species this induction of connexins can be mimicked by a traumatic stimulus. In conclusion, suppression of connexin expression in the endometrium is a characteristic cell biological indication for receptivity in different species. The limited induction of direct cell-to-cell communication properties, probably due to locally acting blastocyst signals, seems to be a precondition for embryo implantation.

A secure electronic market for anonymous transferable emission permits

Abstract: Electronic Markets as new mechanisms for co-ordinating allocation of goods, are supposed to reduce the trading imminent transaction costs, especially when the traded goods are digitally represented. A market with no transaction costs is theoretically the most efficient possible allocation mechanism. The US government has recently passed the Acid Ruin Act which uses a system of tradable permits to reduce pollution for the first time. In this document we present a new example of a solution for environmental policy with tradable emission permits, that is based on electronic markets. Open electronic markets are able to improve a systems efficiency by solving the difficulties that result from high transaction costs. We introduce the concept of original and anonymous permits, which can be freely traded in a open network without any restrictions. It may be used for other types of electronic documents such as shares, which are only of value, if they satisfy the criteria "Originality". The advantage of anonymity is of an economic nature, especially in terms of acceptance of the open electronic market. An open electronic market in an open network like the Internet is insecure, but it is accessible for a large amount of potential users. To get an open network, where trading is without restrictions, and which is also secure, a set of security services have to be provided. In this work we specify a secure completion phase of an electronic market for free tradable, anonymous and original permits by using cryptographic methods and organisational measures such as digital signatures and trusted third parties.

Splitting Techniques for the Unsteady Stokes Equations

Abstract: A pseudospectral (or collocation) approximation of the unsteady Stokes equations is presented. Using the Uzawa algorithm the spectral system is decoupled into Helmholtz equations for the velocity components and an equation with the pseudo-Laplacian for the pressure. Both the velocity components and the pressure are approximated by polynomials of the same degree N. Compatible velocity and pressure approximations are constructed to ensure that the discrete problem is well posed. The resulting discrete velocity field is identically divergence-free. Only one grid (no staggered grids) with the standard Chebyshev Gauss--Lobatto nodes is used. Here we further compare our treatment with an inhomogeneous Neumann condition for the pressure. This scheme was proposed in [G. Karniadakis, M. Israeli, and S. A. Orszag, J. Comp. Phys., 97 (1991), pp. 414--443]. The comparison shows that the Neumann condition yields somewhat better approximations for the pressure. In the time discretization, a high order backward differentiation scheme for the intermediate velocity is combined with a high order extrapolant for the pressure. It is numerically shown that a stable third order method in time can be achieved. In the case of periodic boundary conditions this result is confirmed by Fourier analysis.

Bolus vincristine and epirubicin with cyclophosphamide and dexamethasone (VECD) as induction and salvage treatment in multiple myeloma

Abstract: The VAD regimen (infusional vincristine, doxorubicin and intermittent high-dose dexamethasone) is widely considered the standard salvage chemotherapy for multiple myeloma resistant to alkylating agents and is increasingly used for induction in previously untreated patients prior to high-dose chemotherapy. We investigated the VECD protocol, a VAD-based regimen using bolus injections of vincristine 1.5 mg day 1 and epirubicin 20 mg/m2 days 2 and 3 with 1 h infusions of cyclophosphamide 200 mg/m2 days 1-3 and oral dexamethasone 20 mg/m2 days 1-5 as induction and salvage treatment in multiple myeloma. Fifteen previously untreated and 25 patients with relapsed or refractory myeloma were included. Cycles were repeated every 3 weeks. In the group of previously untreated patients the response rate was 53% and the median survival has not been reached at 59 months. For relapsed and refractory patients the response rate was 44% and the median survival 13 months. In the group of patients with truly refractory disease on prior chemotherapy a response rate of 47% was achieved, which appears superior to the results observed for VAD alone. The main toxicities were leukocytopenia WHO grade IV and infections grade III/IV with both toxicities being significantly more pronounced in pretreated patients. VECD appears to be an effective regimen for induction and salvage therapy in multiple myeloma. Based on the limited number of patients treated the results are comparable to those reported for VAD, with the advantage that the infusional application of vincristine and the anthracycline is omitted.