bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultra‐fast moving coil actuator for power switches in medium‐voltage grids
Authors: Stroehla Tom , Dahlmann M. , Kellerer T. , Wagner T. , Wagner N. , Sattel Thomas
Published: June 2019

The need for faster power switches leads to the following question: Which technical actuation principle has the highest acceleration potential? This study describes the investigation of electrodynamic moving coil (voice coil) actuators. This principle promises no delay for the excitation field because of permanent magnets and a very small electrical time constant of the moving coil. The aim is to find out the limits of the switching time under practicable conditions. In the study, technical limitations of the actuation principle concerning the dynamic behaviour are shown by an analytical approach. It contains the major parameters like stroke or material of the iron poles, the coil, and the permanent magnets. Furthermore, the study discusses thermal aspects and approaches for the mechanical force multiplying by cascaded arrangements. A magnetically optimised elementary unit can be combined parallel or in series. The mechanical load inertial can be divided into a sufficient number of cascaded actuation units. Consequently, only the inherent moving mass determines the acceleration capability. This optimisation was done analytically with the Lorentz force formula and with finite element method simulations. This article describes both approaches, their results, and the experimental verification. The experimental actuator reaches a switching time of 2.7 ms.
Dynamic security of islanded power systems with pumped storage power plants for high renewable integration – A study case
Authors: Vasconcelos Maria Helena , Beires Pedro , Moreira Carlos Leal , Peças Lopes João Abel
Published: June 2019

This work consists in assessing a real islanded power system from a dynamic security point of view, to support the planned installation, in the near future, of a hydro power plant with pumped storage, aiming to increase the integration of renewable energy. The analysed hydro power plant will include a Pelton turbine as it is a high‐head hydro facility. Due to economic reasons, the adopted water pumping technology consists in fixed speed pumps coupled to induction motors with direct grid connection. It was possible to verify through detailed simulations of this power system's time domain behaviour that, even though the expected installation of this new power plant will bring additional frequency stability constraints, a robust technical solution may be found dealing with the new constraints without increasing the complexity of operation in this islanded power system. The conclusions obtained from this specific case are also valid for similar isolated power systems, namely when hydro pumping stations are being considered to increase time‐variable renewable generation penetration.
Using adaptive control in DFIG‐based wind turbine systems to inhibit power system low‐frequency oscillations
Authors: Asefi Mohammad‐Naser , Jafarian Mohammad , Taherahmadi Javad
Published: June 2019

Considering the growing wind power penetration in power systems, using the flexible control ability of these turbines to enhance power system dynamic behaviour has been investigated. One of the major challenges regarding the stability problem of power systems is the low‐frequency oscillations (LFOs) of synchronous generators in a power system. Usually, power system stability units are used to damp these oscillations, but using wind turbine systems for this purpose has been suggested in recent studies. In this regard, mostly a linear supplementary control loop has been employed in the control system of wind turbines. Applying a linear structure for the supplementary control loop does not result in optimum performance since the power system operating conditions and the wind turbine power generation change continuously. In this study, adaptive control is used to design the supplementary loop. Doubly‐fed induction generator (DFIG)‐based wind turbine systems are used for this study. Since adaptive control parameters tend to optimum values, applying this controller will provide better damping for power system (LFOs at different wind speeds, as shown in this study.
Enabling wind farm to be black‐start source by energy storage
Authors: Liu Weipeng , Liu Yutian
Published: June 2019

An energy storage system (ESS) sizing method is proposed to enable wind farm (WF) to be a black‐start (BS) source. This method handles three challenges: firstly, ESS has enough power to help WF start up. Secondly, the WF together with ESS is modelled as a virtual synchronous generator (VSG), and its frequency regulation capability is considered when sizing ESS. Thirdly, the power and capacity of ESS are determined so that VSG can deliver the required power during black‐start. Instead of using wind speed probability distribution, kernel density estimation is used in this paper to directly estimate the probability distribution characteristics of ESS sizing. Simulation results show that with minimum investment cost on ESS, WF is able to be BS source.
Wide area coordinated control for low‐frequency oscillations damping in a wind‐integrated power system
Authors: Gupta Abhilash Kumar , Verma Kusum , Niazi Khaleequr Rehman
Published: June 2019

The increasing wind integration in present grids to generate clean energy escalates the problem of low‐frequency oscillations (LFOs) in the system. Here, a wide area‐based coordinated control strategy of power system stabilisers (PSSs) and doubly fed induction generator's (DFIGs) power oscillation dampers (PODs) is presented to improve the system damping. An improved eigenvalue‐based objective function is employed to optimally tune the variables of the controller using whale optimisation algorithm (WOA). The impact of DFIG location and thus the suitable wind farm locations are also found out using eigenvalue analysis and dynamic sensitivity analysis. The results are investigated on IEEE 68 bus test system highlighting the effectiveness of proposed strategy for a wide range of operating scenarios.
Influence of PLL on synthetic inertia of DFIG wind turbine in droop controlled microgrids
Authors: Eberlein Simon , Rudion Krzysztof
Published: June 2019

Islanded microgrids allow for a continuous supply of customers even when there is an outage in the bulk power system. The frequency control and stability in microgrids is an ongoing field of research. This work investigates the influence of synthetic inertia control of doubly‐fed induction generator wind turbines on the dynamics of inverter dominated microgrids with droop control. A special focus is placed on the impact of the phase‐locked loop dynamics.
Electric vehicle charge scheduling (EVCS) with PV assistance for variable energy purchase in a multi‐aggregator environment
Authors: Gupta Vishu , Konda Srikanth Reddy , Kumar Rajesh , Panigrahi Bijaya Ketan
Published: June 2019

With the anticipated growth in use of electric vehicles (EVs) due to their benefits in environmental conservation and their potential as an energy storage device, corresponding charging facilities will also observe a growth. EVs require a charging infrastructure that supports a scenario which is capable of handling a large number of scheduling requests. However, this may result in a greater load on the grid. To mitigate the impacts of the increased charging load on the grid, photovoltaic (PV)‐assisted charging stations, or PVCS, are proposed here. The benefits of PVCS are evaluated from the point of view of aggregator profits and energy consumption from the grid for a greater number of scheduling requests. With the use of PV at charging stations, it is found that for the period in which PV and battery storage are active, a majority of the charging requests are scheduled through the PV/Battery assist. Thus, reducing the effect on the grid along with an improvement in the total profit of the aggregators.
Trace element geochemistry of carbonates in the Jurassic Lusitanian Basin records mineral-fluid interactions
Authors: Gonçalves Mário A. , Vuckovic Maja , Fiorelli Alfonso , Barrulas Pedro , Mirão José
Published: June 2019

Carbonate rocks in sedimentary basins are reactive and can record complex histories of events associated with fluid flow in these basins. These include processes of dolomitization and dedolomitization. In this work we provide some preliminary data where distinct calcite and dolomite generations in the Jurassic Lusitanian Basin were analysed by LA-ICP-MS for trace elements in order to characterize chemical signatures of fluid-mineral interaction. It was observed that different carbonate generations can preserve the range of certain trace metal concentrations, but later calcites have distinctly higher contents in REE, Th and U, and Ba. Dolomites also show distinct chemical signatures but lack of analytical and spatial resolution does not allow quantification of the precursor calcite relicts. However, these processes point to the action of basinal fluids triggered by distinct tectonic episodes and associated volcanic activity.
Interaction of thermal waters with carbonate and aluminosilicate minerals: a case study of Bang mineral hot spring, Central Vietnam
Authors: Novikov Dmitry A. , Van Phan Thi Kim , Van Tuyen Doan , Thu Do Thi , Dultsev Fedor F. , Chernykh Anatoliy V. , Hoan Tran Viet
Published: June 2019

Results of the studies of water-rock interactions for the Bang thermal water system (Bang Mineral Hot Spring) in Kuang Binh province, Central Vietnam, are presented for the first time. It was established that the thermal waters (62.1-97.1 °C) with total mineralization of 255-659 mg/dm3 of HCO3-Na composition are supersaturated with respect to carbonate minerals (calcite, magnesite, and dolomite) and saturated with respect to albite, microcline, laumontite, and glaucophane. The waters with the outlet temperature of 24.3-34.5 °C, with mineralization 44-87 mg/dm3 and composition HCO3-Cl-Na-Mg are unsaturated with respect to carbonates and are in the fields of stability of clay minerals: kaolinite, illite, Na-, Ca-, and Mg-montmorillonite. Theseresults are in good agreement with the results of the isotope composition analysis of the hydrothermal vents (δD, δ18O and 3H), according to which the time of water circulation for the first-group is higher than 60 years and may reach more than 1000 years, while for the second-group water it does not exceed 50 years.
The Annenskiy thermal waters as the certain stage of the water-rock interaction (Far East, Russia)
Authors: Zippa Elena , Bragin Ivan , Chelnokov George , Kharitonova Natalia
Published: June 2019

Chemical composition and saturation degree of the Annenskiy thermal waters to minerals of water-bearing rock have been considered in the manuscript. It is shown that the thermal waters are low mineralized, alkaline and belong to HCO3-Na type. The thermal waters-rock system is equilibrium-nonequilibrium. It means that the waters dissolve primary minerals continuously, never reaching saturation (anorthite, K-field spar and etc.), and form new secondary mineral phases simultaneously, reaching saturation (gibbsite, montmorillonite, albite and etc.). Besides, peculiarities of the equilibrium with minerals of water-bearing rocks for surface and ground waters of the studied region was considered. It is established that the thermal waters are ahead of surface and ground waters and represent the certain stage of the water-rock system evolution. The stage is characterized by the certain chemical composition (TDS=148-317 mg/L, HCO3-Na, SiO2=9-80 mg/L), complex of secondary minerals (calcite, albite, laumontite and etc.) and special geochemical environment (pH 8.2-8.6).
Characteristics of dissolved organic matter in shallow groundwater in the Hetao basin
Authors: Qiao Wen , Guo Huaming , Shi Quan , Zhao Bo
Published: June 2019

Dissolved organic matter (DOM) in both high As groundwater and low As groundwater were sampled from the Hetao basin and characterized by FT-ICR-MS for OM molecular characteristics. Results show that the greater number of molecular formulas was identified in DOM of high As groundwater (5125), compared to the number in DOM of low As groundwater (3603). Among them, lignins and aromatic structures were the most abundant compounds in both high As groundwater and low As groundwater, with 4434 formulas and 2944 formulas identified, respectively. The number of biodegradable compounds (aliphatic/proteins, lipids, and carbohydrates) was less in high As groundwater (197) than that in low As groundwater (279). Higher proportion of lignins and aromatic structures (86.5%) would lead to complexation between As and DOM, which enhanced As mobility. On the other hand, higher proportion of lignins and aromatic structures and lower proportion of bioavailable compounds in high As groundwater supported the hypothesis that more bioavailable compounds were consumed and resulted in the enrichment of lignins and aromatic structures and As release into groundwater.
Transfer of chemical elements in vapor-gas streams at the dehydration of secondary sulfates
Authors: Bortnikova Svetlana , Yurkevich Nataliya , Devyatova Anna , Abrosimova Natalya , Saeva Olga , Cherny Nikolay , Palchik Nadezhda , Danilenko Irina , Shuvaeva Olga , Troitskii Dmitry
Published: June 2019

The elemental composition of vapor-gas streams obtained during heating of secondary hydrous sulfates are presented. Samples of abundant sulfate intergrowth were collected at the Belovo waste heaps and heated at 60ºC in experiments to collect condensates of the releasing vapor-gas streams. A wide spectrum of major and trace elements was determined in the condensate. Chemical elements can be absorbed by the water vapor and migrate with this phase during the dehydration of hydrous sulfates. To determine the mechanisms of migration and the sources of elements in vapor-gas streams, a study of the features of certain hydrous sulphates (antlerite, goslarite, starkeyite, gunningite, siderotile, sideronatrite) by stepwise heating up to 60ºC was conducted. Alteration in the phase composition is controlled by powder X-ray diffractometry. It was determined, that antlerite and starkeite remain stable throughout the temperature range. The beginning of the separation of structural water in goslarite and siderotile occurs at 40°C. Goslarite and sideronatrite at 40°C lost water molecules and transformed to gunningite and Na-jarosite, correspondingly. Structure of siderotile was loosened. The modes of occurrence of the chemical elements in sulfates and pore solution determine the concentrations of elements in the condensates.
Paleoenvironmental considerations based on geochemistry and mineralogy of a Miocene lacustrine calcrete, southern Portugal
Authors: Rodrigues Ana Luísa , Dias Maria Isabel , Prudêncio Maria Isabel , Rocha Fernando , Ruiz Muñoz Francisco , Marques Rosa , Luz González-Regalado María , Russo Dulce , Cardoso Guilherme
Published: June 2019

A lacustrine carbonate facies has been investigated in Middle Miocene successions of the western side of the Moura-Marmelar basin, Southern Portugal in order to evaluate paleoenvironments in which carbonates formed, by using geochemistry and mineralogy. The studied formation corresponds to a recent unearthed section of a calcrete with an homogeneous carbonate facies comprising fine, whitish, and powdery material, and the only detected difference is a slightly hardness decrease towards the top, as well as an increase of weathered rock fragments (schist). The calcrete is calcium rich, even some magnesium enrichment was observed at the middle level, which is differentiated by a general depletion of all chemical elements, particularly REE, in both the bulk and clay-size fraction. Regarding the mineralogy, calcite prevails, and dolomite is only present in the middle level of the calcrete, together with a smectite enrichment, suggesting changes to more alkaline and low drainage, lacustrine and arid to semi-arid conditions.
Using the multivariate statistical analysis for understanding of chemical composition of saline lakes in south part of Western Siberia, Russia
Authors: Kolpakova Marina
Published: June 2019

Major ion and trace elements chemistry of fifty-eight water samples of southern part of Western Siberia (Russia) were analysed with a suite of statistical techniques (using R programming language), in an effort to explain the key processes affecting chemical composition of saline lakes. The database included data about well, river, and lake waters and groundwater. According to performed cluster analysis of chemical data, all lakes in the area can be divided in to 5 main groups and their chemical composition very similar to rivers and deep groundwater. Shallow groundwaters are more enriched in Ca2+ and Mg2+. Principal component analysis (PCA) identified four main principal components, with the first principal component (PC1) accounting for 44.3% and representing the process of salinization, and PC2 and PC3 (17.9 and 8.6% of total variance) controlled by water-rock interaction process of carbonates/sulphates precipitation and aluminosilicates formation.
Chemical and stable isotope composition of surface and groundwater in the surroundings of the Los Humeros Caldera, Puebla, Mexico
Authors: Kretzschmar Thomas , Lelli Matteo , Alfaro Ruth , Sanchez Juan Ignacio , Ramos Yann Rene
Published: June 2019

It is important to develop a regional hydrogeological model to identify possible recharge and discharge areas for a sustainable use of a geothermal reservoir. The Los Humeros geothermal area is situated within five surficial watersheds and coveres an area of more than 15.000 km2. A total of 208 well and spring samples were collected between June 2017 and November 2018. The stable isotope data for this region define a regression line of δDH2O = 8.032·δ18O + 12 and indicate that groundwater is recharged by regional precipitation. At least 39 groundwater wells, with a maximum temperature of 35 °C, show temperatures above the reported mean average surface temperature of 15 °C. Characteristic elements for geothermal reservoir fluids (B, Li, As) are also present in these groundwaters, indicating a possible connection between the reservoir fluid and the local groundwater through local fracture systems. Concentration of B in these hot wells is between 150 and 35000 ppb.
Chemical alteration of sediments on early stage of existing of hydrothermal systems in spreading zones of sedimented ridges (hydrothermal field “Dead Dog”, Middle Valley, Juan de Fuca Ridge)
Authors: Khakhina Alexandra , Kurnosov Victor , Konovalov Yurii , Churkina Valeriya , Galin Konstantin
Published: June 2019

In sediments from Holes DSDP 858B, D, F, located near the active hot vent on the thermal field “Dead Dog” in the northern part of the Juan de Fuca Ridge, Middle Valley, a redistribution of chemical elements occurs as a result of solution-rock interaction. During this process, the increase/decrease of their content in hydrothermally altered sediments inversely reflects the decrease/increase of their content in the solution. Nonregular distribution of microelements and REE’s in hydrothermally altered sediments, like a layer pie, reflects the participation of both ascending hydrothermal fluids and lateral flows of hydrothermal solutions in alteration of chemical composition of sediments.
New orogenic type gold occurrences in the Uyanga ore knot (Central Mongolia)
Authors: Sodov Ariunbileg , Gaskova Olga , Gankhuyag Altansukh , Lkhagvasuren Dagva-Ochir , Dorjsuren Otgonbaatar , Tumen-Ulzii Oyunchimeg , Altanbaatar Battushig
Published: June 2019

The Khangay-Khentey belt is located in central Mongolia (Central Asian Orogenic Belt). The Uyanga ore knot district of the Khangay metallogenic zone are hosted by the lower-middle Devonian volcanogenic-sedimentaryErdenetsogtformation. The new Burgetei, Ult and Senjit gold occurrences were studied. The rocks of theErdenetsogtformation have an irregular gold content: 0.96 g/t Au is determined in quartz vein (BG-7/16), Au content is highest up to 3.5 g/t in the quartzite-jasper (Ult-7/16 and Ult-9/16) cut by quartz veins in the Ult occurrence. The Senjit occurrence represents Au-Hg-Sb epizonal level of orogenic gold deposits structure with highest Hgand Sb content up to 8.5 ppm and 39 ppm respectively. The Au content of arsenic pyrite of the Burgetei and Ult is below the detection limit by electron microprobe analysis. The Au content of arsenopyrite of the Ult occurrence is highest (up to 238 ppm). The ore-mineral assemblages in the new gold occurrences reflect the differences between three explored sites, formed in the course of fluid evolution during the water-rock interaction. Variable concentrations of indicative elements (As, Te, Sb, Hg) and their ratios confirm this fact.
XAFS analysis of Arsenic bound in holocellulose extracted from organic-rich contaminated sediments
Authors: Hara Junko , Norota Susumu
Published: June 2019

The arsenic bound in holocellulose, a precursor of humic substances extracted from organic contaminated sediments, was investigated using XANES (x-ray adsorption near-edge structure) and EXAFS (extended x-ray absorption fine structure) with fluorescence mode. The most abundant arsenic bound in holocellulose was As-O in the first coordination sphere. Sulphur and carbon were also found in a neighbouring coordination shell around arsenic. The arsenic oxidation state was judged to be As (III) by As K edge XANES spectra as a shift to higher absorption edge energy with the increasing formal oxidation state. This arsenic speciation and bounding were well matched with biochemical mechanisms of arsenic absorption into plants.
Sorption of 137Cs, 90Sr, Se, 99Tc, 152(154)Eu, 239(240)Pu on fractured rocks of the Yeniseysky site (Nizhne-Kansky massif, Russia)
Authors: Rozov Konstantin , Rumynin Vyacheslav , Nikulenkov Anton , Leskova Polina
Published: June 2019

The study demonstrates the effect of sorption properties of fractured host rocks from the Yeniseysky site (Nizhne-Kansky rock massif, Krasnoyarsk region) on the migration of dissolved radioactive components (137Cs, 90Sr, 79Se, 99Tc, 152(154)Eu, 239(240)Pu) in the deep geological conditions of a high-level radioactive waste repository. Estimates of radionuclide distribution coefficients between the aqueous solution and fractured rocks obtained from sorption experiments. The influence of various petrographic types and fracture-filling substances on the retardation of radioactive components has been investigated. Based on the results of sorption experiments, we concluded that the type and attributes of rock discontinuities, as well as the mineral composition of the material in fractures, are crucial for the immobilization of radionuclides during their migration through a geological environment.
Use of C–Cl CSIA to elucidate origin and fate of DCM in complex contaminated field sites
Authors: Blázquez-Pallí Natàlia , Shouakar-Stash Orfan , Palau Jordi , Trueba-Santiso Alba , Varias Joan , Bosch Marçal , Soler Albert , Vicent Teresa , Marco-Urrea Ernest , Rosell Mònica
Published: June 2019

We used C-Cl dual isotope analysis and microcosm studies for elucidating the origin and fate of the common groundwater pollutant dichloromethane (DCM) in two different multi-contaminant field sites in Catalonia, Spain; where DCM contamination could be the result of direct solvent releases and/or chloroform (CF) transformation. Known commercial solvents isotopic compositions as well as characteristic C-Cl dual isotope slopes from our anaerobic enrichment culture containing Dehalobacterium sp., capable of fermenting DCM, and other bacteria from the literature were used for field data interpretation.
The isotopic differences and implications for Pacific razor clams along the Washington coast
Authors: Gao Yongwen , Gilbertson Joseph , Zhang Hongyan
Published: June 2019

The Pacific razor clam fishery in Washington State has been co-managed by the coastal Indian Tribes and the state, but little is known about the growth and population structure of the clams due to difficulties of tagging and monitoring. Here we report the results of a pilot study using stable isotope ratios (δ13C and δ18O) of razor clam shells collected in two groups (juvenile vs. adult) and from two sites (Kalaloch Beach and Roosevelt Beach) where distinct biological differences in clam growth and survival rates were observed. The δ13C values of razor clam shells ranged from -2.9 to -0.3‰, whereas δ18O values of the same samples ranged from -2.2 to +1.4‰. Between the two sites there were significant differences in δ13C values especially for juvenile clams. The δ18O profiles from two representative shells demonstrated similar patterns of rapid growth as juveniles and seasonal patterns throughout the life span. Profiles of δ13C were sinusoidal but did not show seasonality and signatures of ocean acidification. We concluded that stable isotope analysis of razor clam shells is a potential new tool in shellfish research and management.
Eccentric rotary swaging variants
Authors: Ishkina Svetlana Ortmann , Toenjes Anastasiya , Schenck Christian , von Hehl Axel , Zoch Hans-Werner , Kuhfuss Bernd
Published: June 2019

Rotary swaging is an incremental cold forming process that changes beneath the geometry also the microstructure and mechanical properties of the workpiece. Especially a new process design with Eccentric Flat Shaped Dies (EFSD) influences both the kind and amount of stress and plastic strain and consequently the material structure, and hence the material and workpiece properties. Eccentric rotary swaging typically provides a helical material flow. According to the process parameters the microstructure features a typical eddy pattern with a spiral shaped grain orientation. The forming process can be carried out in one or more process steps. In a multistage process, it is possible to change the feed direction and, hence, the material flow helix direction. This approach can be used as a possibility to improve the homogeneity of the workpiece and material properties. In addition, for this aims an intermediate heat treatment in multistage forming operations could be realized. Following the goal of optimizing the final properties, the question arises how these mechanical and thermal treatments affect the material microstructure and the forming properties of the workpiece and how they interact. Experiments were conducted with austenitic stainless steel rods of grade AISI304. The effects of the varied feed direction, feed velocity and heat treatment between the forming operations are discussed.
Einsatz von Protonenpumpenhemmern bei Patienten mit Leberzirrhose – eine Umfrage unter Hepatologen in Deutschland
Authors: Horvatits Thomas , Drolz Andreas , Wehmeyer Malte , Steib Christian , Trebicka Jonel , Lohse Ansgar W. , Kluwe Johannes
Published: June 2019

Einleitung Protonenpumpeninhibitoren (PPIs) gehören zu den weltweit am häufigsten verordneten Medikamenten. Vor allem bei Patienten mit Leberzirrhose wurden Verschreiberaten von bis zu 78 % berichtet. PPIs scheinen mit relevanten Nebenwirkungen, wie erhöhtem Risiko für nosokomiale Infektionen, spontan bakterieller Peritonitis oder dem Auftreten einer hepatischen Enzephalopathie assoziiert zu sein. Aus diesem Grund war es Ziel dieser Umfrage, die Verschreibungspraxis von PPIs bei Patienten mit Leberzirrhose in Deutschland zu erheben.

Methoden Die Daten wurden mittels Web-basierter Befragung erhoben. Hierfür wurde eine Einladung über die Newsletter der Deutschen Gesellschaft für Gastroenterologie, Verdauungs- und Stoffwechselkrankheiten (DGVS), des Berufsverbandes Gastroenterologie Deutschland (BVGD) und der Arbeitsgemeinschaft universitärer Gastroenterologen (AUG) versandt.

Ergebnisse 61 Personen haben an der Umfrage teilgenommen. Insgesamt wurden sehr hohe PPI-Verschreiberaten von 58 % im stationären, sowie 44 % im ambulanten Bereich berichtet. Beinahe die Hälfte der Befragten gab an, PPIs bei medizinisch fraglicher Indikation einzusetzen (z. B. unspezifische abdominelle Beschwerden). Bei einem Drittel der Patienten könnte die bestehende PPI-Therapie nach kritischer Evaluation wieder beendet werden. 55 % der Befragten gaben an, dass PPIs ihrer Einschätzung zufolge mit relevanten Nebenwirkungen assoziiert sind. Blutungskomplikationen nach Absetzen einer PPI-Therapie wurden durch die Befragten selten beobachtet.

Schlussfolgerung PPIs werden bei Patienten mit Leberzirrhose in Deutschland sehr häufig verordnet. Ein Problembewusstsein bezüglich eines insgesamt unklaren Risiko-Nutzen-Verhältnisses scheint vorhanden zu sein. Prospektive Untersuchungen sind dringend nötig, um die Evidenzlage hinsichtlich Indikation und Dauer einer PPI-Therapie bei Patienten mit Leberzirrhose zu erhärten.
Abgeblitzt – Kolumne
Authors: Schiewack Michael
Published: June 2019

Früher hatten Praxisinhaber kein Problem damit, offene Stellen nachzubesetzen. Es gab Bewerbungen ohne Ende. Im Gegensatz dazu müssen sich Arbeitgeber heutzutage nicht nur selbst bei potenziellen neuen Arbeitnehmern bewerben – sie müssen auch Körbe einstecken können.
Partnerschaft DKPM-DGPM
Authors: Zwaan Martina de , Herrmann-Lingen Christoph
Published: June 2019

Das DKPM wurde 1974 gegründet und versteht sich als interdisziplinäre wissenschaftliche Fachgesellschaft. Die DGPM wurde 1992 mit der Einführung des Facharztes für Psychotherapeutische Medizin, später Psychosomatische Medizin und Psychotherapie gegründet. Sie hat sich 2005 mit der Allgemeinen Ärztlichen Gesellschaft für Psychotherapie (AÄGP) zusammenschlossen und vereint heute vorwiegend niedergelassene Fachärzte und Ärzte mit der Zusatzbezeichnung Psychotherapie.
Sexualpädagogik in der Sekundarstufe I in
Österreich
Authors: Depauli Claudia , Plaute Wolfgang
Published: June 2019

Einleitung Das WHO-Regionalbüro für Europa und die
Bundeszentrale für gesundheitliche Aufklärung (BZgA) haben 2010
Standards für Sexualerziehung in Europa veröffentlicht, um einen Überblick über
die Themen der Sexualerziehung zu geben, die in der Schule angepasst an
verschiedene Altersstufen behandelt werden sollten. Sie sollen gewährleisten,
dass Sexualkundeunterricht in Europa entwicklungsangemessen und von einheitlich
guter Qualität ist.

Forschungsziele Österreichische Eltern bzw. Erziehungsberechtigte und
Schüler*innen wurden nach der Bedeutung der von den WHO-Standards abgedeckten
Themen befragt sowie nach Aspekten, die sie sich für eine erfolgreiche
Sexualerziehung wünschen.

Methoden Es wurden standardisierte Online-Fragebögen entwickelt, die durch
die Direktor*innen der Schulen den Eltern und Schüler*innen zugänglich gemacht
wurden. Es wurden insgesamt 9 196 Teilnehmende befragt, davon in der hier
dargestellten Altersgruppe der 13- bis 15-jährigen Schüler*innen 2 204 Personen.
Es handelte sich um 1 571 Jugendliche (weiblich: 742, männlich: 820), und 633
Eltern (weiblich: 523, männlich: 110). Die Teilnehmer*innen bewerteten die
Wichtigkeit der Themen anhand von 5-stufigen Likert Skalen.

Ergebnisse Die Eltern der 13- bis 15-jährigen Schüler*innen beurteilen
sexualpädagogische Inhalte insgesamt als wichtig, wobei für Mütter die Relevanz
höher ist als für Väter. Eltern wünschen sich gut ausgebildete Lehrkräfte.
Besonders wichtig sind ihnen Informationen zu biologischen Grundlagen und
Hygiene sowie die Rechte und der Schutz der Kinder und Jugendlichen. Am Beispiel
Homosexualität zeigt sich, dass es auch Inhalte gibt, deren Behandlung besonders
für Väter nur wenig Wichtigkeit besitzen.

Schlussfolgerung Zeitgemäße Sexualpädagogik muss sich einer Vielzahl neuer
Herausforderungen stellen und entwicklungsangepasst ab der frühen Kindheit zum
Wohl der Kinder und Jugendlichen evidenzbasiert Informationen bereitstellen.
Synthetic Utility of One-Pot Chemoenzymatic Reaction Sequences
Authors: Doyon Tyler J. , Narayan Alison R. H.
Published: June 2019

In recent years, there has been a rapid and sustained increase in the development and use of one-pot chemoenzymatic reaction processes for the efficient synthesis of high-value molecules. This strategy can provide a number of advantages over traditional synthetic methods, including high levels of selectivity in reactions, mild and sustainable reaction conditions, and the ability to rapidly build molecular complexity in a single reaction vessel. Here, we present several examples of chemoenzymatic one-pot reaction sequences that demonstrate the diversity of transformations that can be incorporated in these processes.
MOLECULAR DEFECTS OF THE FACTOR IX GENE CAUSING SEVERE HAEMOPHILIA
Authors: Ludwig B M , Schwaab R , Brackmann H H , Egli H , Olek K
Published: June 2019

Deficiency or functional abnormality of factor IX protein leads to the X-linked recessive haemorrhagic disorder known as haemophilia B. Using the factor IX cDNA probe pTG 397 we have studied DNA purified from 40 patients afflicted with haemophilia B. Restriction analysis was carried out using Eco RI, Taq I and Xmn I which give result to DNA fragments representing 99 % of the whole factor IX gene. Mapping the gene this way four patients were shown to have structural alterations in the factor IX gene. To obtain more precise data concerning these mutations we additionally used restriction enzymes Bgl II and Hind III.

The results listed below indicate more patients have to be examined to conclude a strong correlation between inhibitors to factor IX and the presence of gross gene deletions. This view is supported by the findings that two further inhibitor forming patients had no sizable deletions.
LUMINOGRAPHIC VISUALIZATION OF VON WILLEBRAND FACTOR MULTIMERS
Authors: Schneppenheim R , Plendl H , Budde U
Published: June 2019

Current methods for visualization of vWF multimers use either autoradiography or enzymatic color development. Radioactive methods bear some risks for laboratory personal and the radioactive antibodies have a relatively short shelf life. Enzyme labelled antibodies used with their usual substrates are less sensitive even with relatively large amounts of antibody.

These drawbacks can be overcome by using peroxidase labelled antibodies and luminol for visualization of vWF multimers. Electrophoresis in LGT agarose and immunoblot on nitrocellulose were performed as described in the literature. The nitrocellulose sheets were immersed in polyclonal anti-vWF antibody (1:500) followed by a peroxidase labelled anti-rabbit antibody (1:500). The subsequent procedures were performed in a dark room. The gels were overlaid by 40 mg luminol suspended in 100 ml TRIS buffer (pH 7.5) and covered with a thin transparent foil. The luminiscence could be detected visually for about 40 minutes. There was enough time to expose up to 10 x-ray films by simply placing the films for some seconds onto the transparent foil.

The method is sensitive enough to allow 1:200 dilutions of normal plasma. Thus plasmas containing substantially less than 10% vWF protein can be evaluated with this method.
PLATELET VON WILLEBRAND FACTOR-INDUCED SPONTANEOUS PLATELET AGGREGATION IN VON WILLEBRAND'S DISEASE
Authors: Gralnick H , McKeown L P , Williams S , van Mourik J
Published: June 2019

We have previously described a form of von Willebrand's disease (vWd) with spontaneous aggregation induced by an abnormal plasma von Willebrand factor (vWf). We have studied the ability of these patient's platelet (P) lysate to induce P aggregation and compared the results with P lysates from other vWd patients.

P were prepared from whole blood by centrifugation on an arabino-galactan gradient. The P yield varied from 86-93%. When 125I purified plasma vWf added to whole blood, it was not detectable in the isolated P preparation. The P were lysed by Triton X-100 and after freezing were used in the assays. We found that as little as 25 ul of P lysate (1 x 109 platelets/ml) induced SPA in normal platelet-rich plasma (PRP). Normal or other vWd did not induce PA when (1) a monoclonal antibody directed the fib-rinogen/vWf binding site on the GPIIb/IIIa was incubated with PRP; (2) when Glanzmann's thrombasthenic PRP was used or (3) when platelets were suspended in a fibrinogenemic plasma. The monoclonal antibodies, 10E5 and PLT-1 directed against the GPIIb/IIIa complex, totally inhibited the P-vWf induced platelet aggregation. SPA did not occur unless the plasma fibrinogen concentration was 40 mg/ml. The monoclonal antibody 6D1 (directed against the plasma vWf binding site on GPIb) only partically inhibited the P-vWf SPA. But an antibody directed against the plasma vWf-GPIb binding domain totally inhibited the SPA. We conclude that P-vWf has a domain similar to plasma vWf which binds to GPIb; however, the P-vWf binds to a site on the GPIb which is not identical to the plasma vWf binding site.
INDUCED ANTIBODIES TO VON WILLEBRAND FACTOR (VWF)
Authors: Johnsson H , Silveira A , Adamson L , Schulman S , Hessel B
Published: June 2019

Plasma from 11 patients have been investigated for the presence of antibodies to VWF using an immunoblot-ting system. Eight patients had severe haemophilia A and 3 had severe VW's disease (VWD). One haemophiliac had a high titer of neutralizing activity against VIII:C, and two had previously shown neutralizing activity against VIII:C. Neutralizing activity against ristocetin cofactor was demonstrated in only two of the VWD-patients. None of the VWD-patients did show antiactivity to VIII:C. All patients except 2 haemophiliacs had been transfused with factor concentrate within the last three weeks before blood sampling. Four different concentrates had been used.

The following immunoblotting system was used: Highly purified VWF was applied to agarose gels, and electrophoresis performed. The proteins were blotted to nitrocellulose paper and the paper cut into strips. The strips were incubated with diluted plasma or the IgG-fraction of plasma (obtained by precipitation with ammoniumsulphate) from one or the other of the patients. Thereafter, the strips were treated with a second antibody (goat-anti human IgG) labeled with peroxidase before development with α-chloronaphtol. As a negativ control, normal plasma was used. As a positive control, a peroxidase labeled goat-antihuman VWF was used giving the known multimeric pattern of VWF-antigen.

Antibodies to VWF were found in 4 haemophiliacs and in all 3 VWD-patients. The pattern of multimeric bands obtained with the antibodies showed differences in different patients. The in vivo t 1/2 of VIII:C concentrate did not seem to be affected by these antibodies to VWF.
HAEMOSTATIC RESPONSES TO VASOPRESSIN RELEASE DURING COLONOSCOPY
Authors: Hampton K K , Hariman H , Grant P J , Prentice C R M
Published: June 2019

Vasopressin (aVP) infusions resulting in plasma concentrations comparable to those occurring during stress result in increasesinfactor VIII coagulant activity (FVIIIC) and increases in plasminogenactivator activity (PAA) as measuredby shortening of the euglobulin clot lysis time (ECLT). During major abdominal surgey aVP release is accompanied by similar changes in FVIII, PAA and FPA. The relative contributions of vasopressin release and tissue damage during the surgical procedure are not clear. The aim of this study was to investigate haemostatic changes during colonoscopy where bowel manipulation results in endogenous vasopressin release, but surgical tissue damage is absent. The study was performed in 12 patients undergoing routine colonoscopy. Sedation was achieved with pethidine 50 mg and midazolam 5 mg. Samples were taken after sedation, with the colonoscope in the caecum representing maximal bowel manipulation, and 15 minutes after the end of the procedure. Samples were taken for aVP, ECLT, FVIII and fibrinopeptide A (FPA). In 8 patients a complete procedure was performed. Median aVP concentration rose from 0.5 before to 153 pg/ml at maximal bowel manipulation (p < 0.02), PAA rose from 100 to 508% (p < 0.008) and FVIII from 100 to 218% (p < 0.02). The rise in aVP correlated with PAA (r = 0.68 p < 0.004) and FVIIIC (r = 0.74 p < 0.001). In 4 patients the procedure was terminated prematurely after minimal bowel manipulation. Plasma aVP did not change from 0.5 pg/ml and there were no significant changesin PAA andFVIIIC when colonoscopy was abandoned. FPA concentrations did not alter significantly in eithergroup. The results suggest endogenous vasopressin release occurs during colonoscopy and is associated with increased PAA and FVIIIC, providing further evidence that vasopressin has a role in the regulation of haemostasis during stress. The lack of chang in FPA suggests vasopressin release does not initiate thrombin generation and that tissue damage is necessary as the stimulus for fibrin formation.
INCIDENCE OF HIV-1 AND HIV-2 ANTIBODIES IN HEMOPHILIACS
Authors: Schramm W , Gürtler L G , Pohlmann H , Weigel I , Eberie J , Deinhardt F
Published: June 2019

The presence of antibodies to HIV-1 (anti-HIV-1) was tested in 167 hemophiliacs surveyed and treated at Munich hemophilia center. Increasing numbers of HIV infected patients were observed in the years 1981 to 1986 from 0% to 51,5% (86 positive patients in January 1987 of 167 followed patients). Most of the seroconver-sions occured between 1982 and 1984. The 150 clinically severe affected hemophiliacs (F-VIII-levels up to 5% and need of replacement therapy) showed positive HIV-test results in 55,3% (83 patients) and negative results in 44,7% (67 patients). 5 patients died since 1981, one because of AIDS. 17 patients were not seen since 1984, 14 of those belong to the severly affected group, 12 of them were negative. Since spring 1985 only heat or chemically treated clotting factor preparations are used for substitution. Despite this still 5 seroconversions were observed. Two may be attributed to the use of a preparation heat inactivated in dry state, this preparation is no longer used. The other 3 seroconversions possibly were caused by an occasional use of an noninactivated preparation in the beginning of the change to inactivated clotting factor preparations. 38 of the anti-HIV-1 positive sera were tested for the presence of HIV-2 antibodies also. The methods were ELISA,immunofluorescence and immunoblot. HIV-2 (LAV-2) for these tests was kindly provided by L. Montagnier. Antibodies specific for HIV-2 antigens were not detected, but crossreactions were observed between anti-HIV-1 with HIV-2 antigens particularly epitopes on HIV-2-p27.

The data indicate that the use of adequately inactivated clotting factors can prevent infection of hemophilia patients by this route and that HIV-2 was not present in the clotting factor preparations used for the substitution of this group of patients. The incidence of full blown AIDS since 1981 in our group of hemophiliacs is still low (1,2%).
DURATION OF BLEEDING FOLLOWING DENTAL EXTRACTION IN RABBITS:IN FLUENCE OF PLATELET DYSFUNCTION
Authors: Declerck D , Vinckier F , Vermylen J
Published: June 2019

Clinical experience suggests that acetylsalicylic acid prolongs bleeding after dental extraction, but objective evidence is lacking. We have studied the influence of platelet dysfunction on haemostasis following dental extraction in rabbits. Platelet defects were induced by oral administration of acetylsalicylic acid (ASA) or ticlopidine (T). Duration of bleeding was measured in following groups of Dutch rabbits:(A) control animals (n = 32),animals who received (B) ASA 100 mg/kg/day (n = 31), (C) ASA 300 mg/kg/day (n = 12)(D) T 60 mg/kg/day (n = 8) and (E) T 125 mg/kg/day (n = 12). Inhibition of thromboxane B2-formation was more than 99% in animals receiving ASA. ADP-induced platelet aggregation was inhibited in animals receiving T. Four front teeth were extracted on day 7 and tooth socket bleeding times were determined by inspecting the wounds at 5 min intervals. Oozing sockets were counted. The figure below shows the results.

It is concluded that ASA or T prolong bleeding following dental extraction in rabbits. The effect appears to be dose-dependent for T. This model may be useful for evaluating haemostatic procedures applicable to patients with platelet disorders.
THE LUPUS ANTICOAGULANT DOES NOT INHIBIT THE RELEASE OF PROSTACYCLIN FROM HUMAN ENDOTHELIAL CELLS
Authors: Petraiuolo W , Bovill E , Hoak J
Published: June 2019

Decreased endothelial cell production of prostacyclin (PGI2) in response to the lupus anticoagulant has been previously demonstrated, and postulated to have a causal relationship to the thrombotic events associated with the lupus anticoagulant. Five patients who exhibited the anticoagulant were studied in an effort to determine if a relationship exists between exposure of endothelial cells to the lupus anticoagulant and decreased production of prostacyclin (PGI2). Human endothelial cells derived from human umbilical vein grown in culture were exposed to IgG fractions of patient plasmas containing the lupus anticoagulant. The amount of PGI2 released was determined by radioimmunoassay for 6-keto-PGF-l-alpha. The average PGI2 release in the controls was 20.6 picomol/500,000 endothelial cells, whereas those cells exposed to the lupus anticoagulant had a range of 25 to 114 picmol/500,000 cells. We were unable to demonstrate inhibition of the release of PGI2 by human endothelial cells, following exposure to the lupus anticoagulant.

(Supported by NIH Grant HL 33723-2 and a Specialized Center of Research in Thrombosis Award HL 35058-01 from the National Heart, Lung and Blood Institute.)
PRENATAL DIAGNOSIS OF HEMORRHAGIC DISORDERS
Authors: Forestier F , Daffos F , Kaplan C , Champeix P
Published: June 2019

Utilizing an easy and safe procedure for fetal blood sampling in utero. we have studied 123 fetuses for congenital oracquire hemorrhagic disorders.

Usually, the diagnosis is performed at the 18th week of gestation. To date, no fetal less or premature labor has beenattributed to these fetal samplings. Theduration of the procedure was less than 10 minutes in 90 % of the cases. Direct blood sampling with a needle guided by ultrasound is safer for fetuses and simpler for the patients than fetoscopy. Among the 1.465 samplings the mortality rateis 0.2 %. We have established the basis values for fetal hemostasis when the samplings were performed for non hematological purpose, and could determine the fetal sex which play a role in hereditary disorders. Hemophilia A and B [92 cases]. Willebrand disease, factor XIII, V and VII deficiencies were diagnosed on the existence of a specific fetal deficit. Theknowledge of the fetal primary hemostasis let us to establish the diagnosis of May Hegglin syndrome. Gray platelet syndrome. and Glanzmann's thrombasthenia. There were no diagnostic errors. This procedure offers a new possibility of easily taking iterative samples, until the end of pregnancy, which represents a particular interest in prenatal diagnosis.