bluuebunny/crossref_metadata_2025 huggingface dataset:
GOOSE performance assessment on an IEC 61850 redundant network
Authors: Hosny Tawfeek Essa Mohamed , Crossley Peter
Published: July 2018

Conventionally distribution substations utilise hardwires (copper cables) for achieving different operational requirements such as interlocking, inter‐tripping and automatic transfer systems. The latest substation communication standard IEC 61850 introduced a new method for horizontal communication of digital and analogue messages between devices in the substation called GOOSE or Generic Object Oriented Substation Event. In addition, IEC 61850 adopted seamless redundancy protocols, namely PRP and HSR, to encourage the utilisation of GOOSE communication in high‐dependency applications. Here, the performance of GOOSE communication is assessed under different background traffic conditions in an HSR redundant network. This is achieved by utilising a data quality analyser to inject Ethernet ARP packets simulating background traffic. The network also includes an Ethernet switch, time server, laptop and three IEDs or Intelligent Electronic Devices. The IEDs are natively supporting IEC 61850 with HSR protocol, and configured to exchange GOOSE messages. Test results show GOOSE communication is affected by the traffic, but the severity of the problem, i.e. delays and losses in the communicated messages, depends on the level of traffic, as a percentage of the bandwidth. Tests also show redundancy enhances the overall network reliability via dual paths, limiting the effect of background traffic on the communicated messages..
Utilisation of IEC61850 GOOSE for improvement of EFP sensitivity in compensated MV networks
Authors: Zubic Sinisa , Burek Arkadiusz , Krakowski Marcin , Balcerek Przemyslaw , Fulczyk Marek
Published: July 2018

In this study, the sensitivity of the earth‐fault protection (EFP) in medium‐voltage distribution networks with a compensated neutral point is investigated. An adaptive residual voltage threshold is proposed as a solution for enhanced EFP sensitivity. The optimal threshold adaptation is based on the horizontal communication between a Petersen‐coil (PC) controller and IEDs, utilising IEC 61850 GOOSE messages. The maximum residual voltage information, from a healthy state of the network, is transferred from the PC controller to IEDs, where an optimal residual voltage threshold for the EFP is determined. This adaptation allows maximum protection sensitivity and security to be obtained for each substation and the network state.
Protecting frequency stability using local inertial mapping
Authors: Ubertalli Jean Bosco , Littler T.B.
Published: July 2018

The study investigates the role of inertial mapping in assessing and preserving frequency stability for grids accommodating greater penetration of low‐inertia, intermittent generation, including wind sources. The study considers grid sizing, including large and isolated systems and an approach to limit the excessive rate of change of frequency (ROCOF). Simulation studies using DIGSILENT (Power Factory) and the IEEE 39‐bus grid model with nodal phasor measurements have been used to evaluate the work. The proposed approach identifies areas of weak or strong inertial provision and battery energy storage has been used to release active power during disturbances and provide local energy to lessen the impacts of inertia reduction. The study proposes using frequency and ROCOF measurements during system events to map inertia and calculate energy provision. Inertial measurements are used to determine areas where additional generation or storage is required in order to preserve frequency stability and provide contributory counter‐measures for grid‐level protection.
Impact of ‘intermediate’ sources on distance protection of transmission lines
Authors: Kuflom Melake , Crossley Peter , Osborne Mark
Published: July 2018

A strategy to evaluate the impact of intermediate sources on the performance of transmission line distance protection is proposed in this study. The influence of an intermediate infeed on the sensitivity of the reach setting and the resulting tripping performance of a distance protection scheme is the main emphasis of this study. The proposed strategy considers the effectiveness of various protection schemes on the protection challenges expected on the National Grid transmission network due to future changes in the generation mix. PowerFactory (DIgSILENT PowerFactory software package) will be used to simulate a double circuit transmission network, when a fault occurs and the strength of the main and intermediate sources change from weak to typical to strong. This study discusses various solutions to the problems observed and a methodology for adapting the grading strategy of distance protection as transmission networks evolve into the future.
Return of the dedicated DFR: how IEC 61850 process bus simplifies DFR installation
Authors: Oliveira Lucas B. , Hunt Richard
Published: July 2018

The advantages of a dedicated, standalone DFR are well known: natively synchronised fault records, large record storage capabilities, high sampling rates, numerous types of triggers, and large numbers of analogue and digital recording channels. The main disadvantage to the dedicated DFR is cost: a dedicated DFR must be directly wired to every current, voltage, and status point, resulting in an installed project cost easily ten times the material cost of the DFR itself. However, IEC 61850 process bus makes dedicated DFRs affordable again, by eliminating all field wiring necessary for installing a DFR.
Modelling optimisation and protection outcomes from distributed assets controlled to reduce a PMU based multi‐objective cost function
Authors: Brogan Paul V. , Best Robert , Morrow John , Gharavi Hani , Kubik Marek
Published: July 2018

In this study, the development of a wide‐area, multi‐objective cost function is explained. The cost function is designed for implementation on wide‐area phasor measurement unit data. In this study, the cost function was applied to the IEEE 30 and 57 Bus models for monitoring and control purposes. Although the cost function was originally intended as a situational awareness tool that indicated system health; it has now been applied as a control metric for the operation of on‐load tap changing transformers on a variety of standard IEEE test systems. The system benefits, relative to conventional local control, are quantified. The primary metrics for testing protection outcomes are maximum voltage deviation and line thermal overload. The wide‐area optimisation is assessed from a voltage profile, reactive power demand, and transmission losses. The benefits of this type of wide‐area control are demonstrated in a variety of situations and environments.
Fault detection and location algorithm for DG‐integrated distribution systems
Authors: Manditereza Patrick Tendayi , Bansal Ramesh C.
Published: July 2018

The overcurrent protection on the traditional distribution system uses local measurements and settings as a basis for decision‐making. However, connection of multiple distributed generators with different short‐circuit characteristics makes the local measurements unpredictable, leading to possible loss of protection coordination. In order to solve this problem, this study proposes an algorithm that achieves its protection function through load flow and sensitivity calculations based on voltage measurements. The algorithm is built on a modelling approach that splits the distribution network into a series of overlapping protection zones. The overlapping feature is realised logically through peer‐to‐peer communications between intelligent agents located in adjacent zones. A sensitivity‐based electrical signature was identified that is generated when a fault occurs within a zone. Simulation results show that the proposed protection algorithm is able to identify the zone in which the fault has occurred and the specific faulted node or line section in that zone. The fault current contributions, or no contributions, of the distributed generators (DGs) do not impact the operation of this algorithm.
Automatic analysis of faulty low voltage network asset using deep neural networks
Authors: Mastroleo Marcello , Ugolotti Roberto , Mussi Luca , Vicari Emilio , Sassi Federico , Sciocchetti Francesco , Beasant Bob , McIlroy Colin
Published: July 2018

Electrical distribution network is constantly ageing worldwide. Therefore, probability of cable faults is increasing over time. Fast recovering of damaged networks is of vital importance and a quick and automatic identification of the failure source may help to promptly recover the functionality of the network. The scenario we are taking into consideration is a vast number of recording devices spread across a network that constantly monitor low voltage cables. When the current of a cable reaches a very high value, data is sent to a central server which analyses it through a variant of a Variational Auto Encoder (VAE), a deep neural network. This VAE has been trained by using historical data collected from several hundreds of faults recorded, but in which only a handful of them has been labelled by an on‐site analysis of the fault. Data used for training is simply the recorded levels of voltages and currents, after a simple pre‐processing step. The final goal is to let the network distinguish if the fault occurred in a point of the cable, on a joint, or at the pot‐end located at the termination. A preliminary evaluation of its ability to generalise over the non‐labelled samples shows encouraging results.
Analysis of the characteristics of fault‐induced travelling waves in MMC‐HVDC grid
Authors: Tang Lanxi , Dong Xinzhou , Shi Shenxing , Wang Bin
Published: July 2018

As the ability of DC circuit breaker is limited, transmission line protection has to identify the fault and inform the DC circuit breaker to cut off fault current as quickly as possible after a fault occurs on the transmission line of modular multilevel converter‐based high‐voltage direct current (MMC‐HVDC) grid, in order to prevent the fault current from exceeding the ability of the DC circuit breaker. MMC‐HVDC grid requires the speed of transmission line protection to be extremely fast. Travelling wave protection utilises the fault‐induced travelling waves to construct protection criteria. As fault information firstly propagates in the form of travelling waves in the grid after a fault, travelling wave protection can achieve the fastest operation speed in theory, so it is an ideal choice for MMC‐HVDC grid. This study analyses the characteristics of fault‐induced travelling waves in the MMC‐HVDC grid and the results can be the foundation of travelling wave protection of transmission line in MMC‐HVDC grid.
Analysis on current characteristics of PMSG under grid three‐phase fault
Authors: Chang Zhongxue , Song Guobing , Wang Ting
Published: July 2018

Fault characteristics analysis is precondition of relay protection. Theoretical derivation of permanent magnet synchronous generator (PMSG) fault current is necessary. In accordance with the theory that grid‐side converter of PMSG is a power balance system under control action, an electromagnetic transient model of PMSG was proposed. Based on it, the active and reactive current was deduced and then the expression of three‐phase fault current was obtained and its components, frequency, and attenuation speed of every component and other characteristics were analysed comprehensively. Simulation on PSCAD and field fault recording data as practical analysis verifies that the expressions and the characteristics are correct. The results of this paper are not only important to relay protection, but also are references to transient calculation and transient modelling.
Busbar earthfault protection methods on LCI static starter turbogenerators using generator protection relays
Authors: Aguilar Carlos , Socorro Ayoze
Published: July 2018

The purpose of this document is to highlight the special treatment or requirements of protection functions when applied to load commutated inverter (LCI) static starter turbogenerators. Static starting of TG's is accomplished by using an LCI, adjustable speed drive system, to motor the synchronous machine and coupled turbine. More specifically, the focus will be on 64B function (busbar earthfault protection) when achieved through 59BN function (neutral overvoltage).
Requirement analysis of hybrid direct current breaker in multi‐terminal high‐voltage direct current grids
Authors: Langwasser Marius , De Carne Giovanni , Liserre Marco , Schindler Thorsten
Published: July 2018

Hybrid direct current circuit breakers (DCCB) are the most adopted solution to clear high DC fault currents in short time. Existing literature does not analyse recently validated commercial breakers. This article provides an overview about hybrid DCCB and a list of criteria to evaluate and compare the performance of existing or new DCCB designs. Additionally, general measures are proposed to assess the suitability of the DCCB in a specific grid situation. Accordingly, the fault current evolution under pole‐to‐pole faults in different parts of a multi‐terminal DC grid is analysed by means of mesh analysis with matrix differential equations. Finally, a grid parameter variation analysis is carried out through PSCAD‐EMTsimulations to compare the presented DCCB concepts.
Influence of mutual coupling modelling on the effectiveness of a distance relaying algorithm applicable to long parallel transmission lines
Authors: Araújo Marcos R. , Pereira Clever
Published: July 2018

This study presents an evaluation of the influence of mutual coupling modelling on the effectiveness of a distance protection scheme suitable for long parallel transmission lines. Sliding single‐line‐to‐ground fault simulations have been carried out in MATLAB using a phase‐domain approach. The output voltage and current signals were applied to the distance relaying algorithm considering exact compensation parameters. It is shown that, for the system considered, assuming parallel transmission lines modelled as a six‐phase line, an average relative error of 1.19% is found for the magnitude of the apparent impedances seen by the relay.
Stellar chemo-kinematics of the Cetus dwarf spheroidal galaxy
Authors: Taibi S. , Battaglia G. , Kacharov N. , Rejkuba M. , Irwin M. , Leaman R. , Zoccali M. , Tolstoy E. , Jablonka P.
Published: July 2018

Context. The great majority of early-type dwarf galaxies, in the Local Group as well as in other galaxy groups, are found in the vicinity of much larger galaxies, making it hard to disentangle the role of internal versus external effects in driving their evolution.

Aims. In order to minimize environmental effects and gain an insight into the internal mechanisms that shape the properties of these systems, we study one of the few dwarf spheroidal galaxies of the Local Group found in isolation: Cetus. This system is of particular interest since it does not follow the Local Group morphology-density relation.

Methods. We obtained Very Large Telescope (VLT) FORS2 spectra (R ∼ 2600) in the region of the nIR CaII triplet lines for 80 candidate red giant branch (RGB) stars. The analysis yielded line-of-sight velocities and metallicities ([Fe/H]) for 54 bona fide member stars.

Results. The kinematic analysis shows that Cetus is a mainly pressure-supported (σv = 110−1.3+1.6 km s−1), dark-matter-dominated system (M1/2/LV = 23.9−8.9+9.7 M⊙/L⊙) with no significant signs of internal rotation. We find Cetus to be a metal-poor system with a significant metallicity spread (median [Fe/H]= − 1.71 dex, median-absolute-deviation = 0.49 dex), as expected for its stellar mass. We report the presence of a mild metallicity gradient compatible with those found in other dwarf spheroidals of the same luminosity; we trace the presence of a stellar population gradient also in the spatial distribution of stars in different evolutionary phases in ancillary SuprimeCam photometric data. There are tentative indications of two chemo-kinematically distinct sub-populations, with the more metal-poor stars showing a hotter kinematics than the metal-richer ones. Furthermore, the photometric dataset reveals the presence of a foreground population that most likely belongs to the Sagittarius stream.

Conclusions. This study represents an important step forward in assessing the internal kinematics of the Cetus dwarf spheroidal galaxy as well as the first wide-area spectroscopic determination of its metallicity properties. With our analysis, Cetus adds to the growing scatter in stellar-dark matter halo properties in low-mass galactic systems. The presence of a metallicity gradient akin to those found in similarly luminous and pressure-supported systems inhabiting very different environments may hint at metallicity gradients in Local Group early-type dwarfs being driven by internal mechanisms.
Die Rechtsfrage – Wie kann ich neben dem Studium als Therapeutin arbeiten?
Authors: Bossow Karsten
Published: July 2018

Ich bin Therapeutin und möchte nun neben meinem Masterstudium weiterhin meine Patienten betreuen. Welche Möglichkeiten habe ich?“

Alessa S. aus Düsseldorf
Gelder für Fort- und Weiterbildungen – Lass dich fördern!
Authors: Winkler Alexander
Published: July 2018

Therapeuten greifen nicht nur für die Ausbildung tief in die Tasche, sie finanzieren meist auch ihre Fort- und Weiterbildung selbst. Das muss nicht sein, findet Alexander Winkler. Er hat zusammengetragen, welche Fördermöglichkeiten es für Therapeuten gibt, und erstaunlich viele gefunden.
Anforderungen an Einrichtungen der Phase C der Traumarehabilitation – Überregionale Traumarehabilitationszentren in der postakuten Rehabilitation
Authors: Simmel Stefan , Müller Wolf-Dieter , Bork Hartmut , Eckhardt Rainer , Keppeler Rolf , Kühne Christian , Krischak Gert
Published: July 2018

Fragestellung Schwerverletzte Patienten benötigen nach Ende der Akutbehandlung eine qualifizierte und lückenlose Rehabilitation. Diese postakute Rehabilitation (Phase C) stellt hohe Anforderungen an die Rehabilitationseinrichtung bezüglich personeller, sachlicher, organisatorischer und räumlicher Voraussetzungen. Aufgrund der Verletzungsschwere und den komplexen Anforderungen an eine postakute, multimodale Rehabilitation besteht ein hoher ärztlicher, pflegerischer, therapeutischer und ggf. psychologischer Einsatz.

Methoden Der Arbeitskreis Traumarehabilitation der Sektion Rehabilitation der Deutschen Gesellschaft für Orthopädie und Unfallchirurgie (DGOU) hat in mehreren Expertenrunden Anforderungen an die postakute Rehabilitation der Phase C bei Schwerverletzten konsentiert.

Ergebnisse Die Arbeit führt die Anforderungen der postakuten Rehabilitation gemäß Expertenkonsens auf.

Diskussion und Zusammenfassung Über eine hohe Qualifikation und entsprechende Infrastruktur überregionaler Traumarehabilitationszentren wird ein lückenloser Übergang in die Nach- und Weiterbehandlung von Schwerverletzten im TraumaNetzwerk DGU® sichergestellt.
Genetische Grundlagen der Posttraumatischen Belastungsstörung (PTBS)
Authors: Weiss Elisabeth M. , Parson Walther , Niederstätter Harald , Marksteiner Josef , Lampe Astrid
Published: July 2018

Bei der Posttraumatischen Belastungsstörung (PTBS) handelt es sich um eine psychische Erkrankung, die nach außergewöhnlich bedrohlichen Situationen (Traumata) auftreten kann und sich durch eine hohe Komorbidität auszeichnet. Jedoch gibt es selbst bei Personen mit dem gleichen traumatischen Erlebnis eine hohe interindividuelle Variabilität bezüglich des PTBS Risikos. Daher liegt die Vermutung nahe, dass biologische Korrelate wie genetische und epigenetische Einflüsse als Risikofaktoren für die Entwicklung einer PTBS eine Rolle spielen können. Im vorliegenden Übersichtsartikel soll der aktuelle Erkenntnisstand der genetischen Forschung bei PTBS vorgestellt werden, wobei der Schwerpunkt auf genetischen Befunden aus Kandidatengen-basierten Assoziationsstudien des monoaminergen Systems und der endokrinen Stressachse liegt. Des Weiteren werden Ergebnisse aus Genom-weiten Assoziationsstudien berichtet und auf die Rolle von Genen als Moderatoren der Effekte von Kindheitstraumen anhand von Gen-Umwelt-Interaktionsstudien und epigenetische Untersuchungen eingegangen. Abschließend wird ein kurzer Ausblick auf die aktuelle Forschung im Bereich der Pharmakogenetik gegeben.
Padrões de referência nutricionais na população de crianças com paralisia cerebral: uma revisão analítica
Authors: Gouveia Mara , Chueire Fernando , Mello Elza
Published: July 2018

Os distúrbios de crescimento e nutrição são problemas de saúde frequentes em crianças com paralisia cerebral (PC). Esses distúrbios nutricionais podem acarretar comprometimento no desenvolvimento motor e cognitivo, na socialização, e na maior necessidade do uso de serviços de saúde e de internação hospitalar. Mesmo sob condições aparentemente adequadas (ambiente apropriado e atendimento médico regular), as crianças com PC crescem mais lentamente do que as sem condições crônicas de saúde e possuem padrões de crescimento únicos. Em geral, as equipes de saúde utilizam como medida de referência as curvas de crescimento para populações sem déficit neurológico, as quais não são adequadas para crianças com PC, já que essa população possui um crescimento distinto. Nas últimas décadas, pesquisadores vem construindo curvas de crescimento específicas para a PC. Até o momento, existem cinco padrões de referência publicados. A escolha do melhor padrão de referência dessa população é uma tarefa difícil. No entanto, as curvas de crescimento elaborada por Brooks et al. parece ser mais confiáveis e são as mais utilizadas nos centros especializados em cuidados dessas e adolescentes. Elas são simples, metodologicamente mais seguras, baseadas em uma amostra grande e representativa de todos os grupos de desenvolvimento motor que os indivíduos com PC possam apresentar e estão relacionadas a desfechos clínicos. Contudo, carece de mais estudos que comprovem a sua qualidade, principalmente em contextos diferentes. No entanto, pela importância de se avaliar cada criança/adolescente com sua curva de crescimento específica para sua enfermidade, sugere-se que ela deva ser integrada na avalição antropométrica junto com outros parâmetros nutricionais na prática clínica.
Disparity Between One- and Two-Stage Factor VIII Assays in Measuring VIIIC in Heparinized Plasma
Authors: Rock G , Palmer D S
Published: July 2018

The level of Factor VIII procoagulant activity (VIIIC) was found to be more than 30% higher in heparinized plasma than in citrated plasma from the same donor when determined by a one-stage assay (1.34 U/ml versus 1.0 U/ml). However, after Al(OH)3 adsorption and two-stage assay, the VIIIC levels were not significantly different for the two types of plasma (0.90 ± 0.25 U/ ml versus 0.82 ± 0.23 U/ml). If a one-stage assay was employed after adsorption, a similar low result was obtained (0.92 ± 0.21 U/ ml versus 0.91 ± 0.12 U/ml). This indicated that the adsorption step itself was responsible for the difference in results. Parallel analyses of other VIII markers demonstrated that more VIIIC antigen (VIIICAg) was removed by adsorption of heparinized rather than citrated plasma (0.33 U/ml versus 0.12 U/ml) although there was no difference in the level of VUI-related antigen (VIIIRAg). The results show that adsorption of heparinized plasma prior to either one- or two-stage assay leads to a greater loss of both VIIIC and VIIICAg activity than observed with citrated plasma and indicate that, when applied to heparin plasma the two-stage assay for VIIIC underestimates the actual VIIIC content.
Clinical Application of a Chromogenic Substrate Method for Determination of Factor VIII Activity
Authors: Rosén S , Andersson M , Blombäck M , Hégglund U , Larrieu M J , Wolf M , Boyer C , Rothschild C , Nilsson I M , Sjörin E , Vinazze H
Published: July 2018

A chromogenic substrate kit for the determination of factor VIII activity (COATEST® Factor VIII) has been evaluated in five different laboratories, one of them using a semi-automated procedure. This chromogenic method was compared to one-stage clotting assays for factor VIII determination in plasmas from healthy subjects, carriers of hemophilia A, severe, mild and moderate hemophilia A as well as von Willebrand’s patients. In all these cases, a high correlation between these two methods was obtained (r = 0.96-0.99, n = 385) with a good agreement of the assigned potencies at all levels of factor VIII. A good correlation (r = 0.94) was also obtained for the levels of factor VIII after infusion of concentrates in six severe hemophiliacs or after administration of DDAVP to von Willebrand’s patients.

The chromogenic method is insensitive to preactivation of factor VIII by thrombin, thus yielding valid potency assignments also in these situations.

The precision was higher with the chromogenic method than with the one-stage clotting assays (C.V. = 2-5% vs 4-15%). Altogether, the new chromogenic substrate method has proven itself suitable for determination of factor VIII in plasma and concentrates.
Protease Inhibitors in Haementeria Leech Species
Authors: Murer E H , James H L , Budzynski A Z , Malinconico S M , Gasic G J
Published: July 2018

Inhibitors, of trypsin, plasmin, α-chymotrypsin and granulocyte elastase were demonstrated in salivary gland extracts from two species of leeches, Haementeria ghilianii and Haementeria officinalis. Preliminary fractionation of salivary gland extracts from Haementeria ghilianii allowed separation of protease inhibitors from hementin a fibrinogenolytic blood anticoagulant. It was found that the anticoagulant activity resided only in hementin-containing fractions and did not parallel protease inhibitory activity.
Prolongation of Platelet Survival in Idiopathic Thrombocytopenic Purpura by High-Dose Intravenous Gamma Globulin
Authors: Uchida T , Yui T , Umezu H , Kariyone S
Published: July 2018

The mechanism of the increase of platelet counts after the intravenous injection of high dose gammaglobulin was evaluated by measuring platelet survival before and after the injection. The platelet survival after treatment prolonged more significantly than that before treatment. There was no evidence of platelet release from bone marrow to peripheral blood. These findings might suggest the inhibition of platelet destruction by transient blockade of reticuloendothelial system.
A Comparison of Spontaneous Platelet Aggregation in Whole Blood with Platelet Rich Plasma: Additional Evidence for the Role of ADP
Authors: Saniabadi A R , Lowe G D O , Barbenel J C , Forbes C D
Published: July 2018

ADP, generated from red blood cells is believed to be responsible for the spontaneous aggregation of platelets in whole blood. This notion is based mainly on the use of enzymes which remove ADP. We have studied spontaneous platelet aggregation in whole blood and autologous platelet rich plasma obtained from 12 healthy male and female volunteers. Platelet aggregation was quantitated by measuring the fall in the number of single platelets counted using a whole blood platelet counter (Ultra Flo 100). In a rotating tube model, the mean fall in the number of platelets due to spontaneous aggregation was 56% in whole blood but, only 3% in platelet rich plasma prepared from the same blood samples. Spontaneous platelet aggregation in whole blood was unaffected by apyrase grade I, but was reduced to 15% by apyrase grade II, to 38% by creatine phosphokinase/creatine phosphate and to 9% by pyruvate kinase/phosphoenolpyruvate. The results of this study provide additional evidence that ADP generated in whole blood triggers the spontaneous aggregation of platelets.
Dihomo-γ-Linolenic Acid in Patients with Atherosclerosis: Effects on Platelet Aggregation, Plasma Lipids and Low-Density Lipoprotein-Induced Inhibition of Prostacyclin Generation
Authors: Szczeklik A , Gryglewski R J , Sladek K , Kostka-Trąbka E , Żmuda A
Published: July 2018

Dihomo-γ-linolenic acid (DHLA), a precursor of monoenoic anti-aggregatory prostaglandins (PGE1, PGD2), was administered for 4 weeks in a daily dose of 1.0 g into 33 patients with atherosclerosis on a basis of a double-blind trial. Comparison of treatment and placebo groups revealed elevation of DHLA in red cell lipids in DHLA-treated subjects. No differences, however, between the two groups could be observed in platelet aggregability, thromboxane A2 generation by platelets, serum cholesterol, PGE1 and PGE2 levels, and in inhibitory activity of low-density lipoproteins against prostacyclin synthetizing system in arteries. The dietary supplementation used did not lead to distinct antithrombotic effects.
Acylated Streptokinase – Plasminogen Complex in Patients with Acute Myocardial Infarction
Authors: Walker Isobel D , Davidson J F , Rae A P , Hutton I , Lawrie T D V
Published: July 2018

BRL 26921 is the p-anisoyl derivative of the primary streptokinase-human plasminogen complex in which the acyl group is specifically located at the catalytic centre of the enzyme. Doses of BRL 26921 ranging from 5 mg to 25 mg were given intravenously or into a coronary artery to 12 patients with acute myocardial infarction. The complex was well tolerated and produced no serious bleeding. Coronary artery reperfusion was demonstrated angiographically in three patients.

In most patients, fibrinogen, plasminogen, α2 antiplasmin and a2 macroglobulin levels fell and the level of fibrinogen degradation products increased acutely post treatment indicating systemic fibrinolytic activation. The degree of this activation was variable but was profound in some. It appeared to be dose related and modified by the presence of streptokinase antibodies. BRL 26921 appears less “selectively” thrombolytic in patients than had been expected from animal models.
Plasmin Inhibitors and Fibrinogen Breakdown During the Initial Phase of Thrombolytic Treatment - The Problem of the α2-Antiplasmin Determination
Authors: Noll G , Lämmle B , Duckert F
Published: July 2018

During the first 3 hr of thrombolytic treatment with porcine plasmin (p-PL) or streptokinase (SK) a rapid decrease of clottable fibrinogen with generation of large amounts of fibrin(-ogen) degradation products (FDP) are found. α2-antiplasmin (α2AP) is rapidly neutralized. Whereas in patients treated with SK more than half of the original plasminogen was consumed, its level remained unchanged during p-PL infusion. When α2AP reaches values below some 20%, spontaneous amidolytic activity towards S-2251 representing either PL-α2-macroglobulin- or SK-plasminogen-complex activity appears. This activity has to be considered in the α2AP assay in order to avoid underestimation of this inhibitor.
Clotting Enzyme Activity Derived from the Coelomocytes of the Sea Star, Asterias Forbesi
Authors: Marcum J A , Levin J , Prendergast R A
Published: July 2018

Clotting enzyme activity was detected in lysates prepared from the coelomocytes of Asterias forbesi following incubation with endotoxin-activated Limulus amebocyte lysate. This activity was not detected in the cell-free coelomic fluid. The enzymatic activity from the sea star lysate hydrolyzed the synthetic substrate S2222 but not S2238 or S2251, and polymerized partially purified Limulus clottable protein. The clotting enzyme activity was not detected following treatment of the sea star cell lysate with endotoxin or with the clotting enzyme from Limulus lysate. The enzymatic activity, generated in sea star cell lysate by the activated Limulus lysate, was inhibited by the addition of benzamidine; and its effect was suppressed with rabbit anti-sera directed against Asterias whole cell lysate, but not with anti-sera directed against the previously reported Sea Star Factor.
Interactions of Purified Rat Factor VIII/von Willebrand Factor with Rat and Human Platelets – Effect of Albumin and Ristocetin
Authors: Dejana E , Furlan M , Barbieri B , Donati M B , Beck E A
Published: July 2018

Rat platelets do not respond to ristocetin in their own plasma nor do they aggregate in the presence of bovine or porcine factor VIII von Willebrand factor (F VIII R:WF) or human F VIII R:WF in presence of ristocetin. However, rat plasma supports ristocetin induced aggregation of washed human platelets. In this study we report on purification of rat F VIII R:WF from cryoprecipitate. Similarly to porcine or bovine material, purified rat F VIII R:WF induced aggregation of human washed fixed platelets. This effect was enhanced by addition of ristocetin and was not modified by addition of albumin. Rat washed platelets were aggregated by ristocetin in the presence of rat or human F VIII R:WF provided that high concentrations of ristocetin are added in a system essentially free of extraneous proteins. Increasing concentrations of albumin dramatically reduced the ability of ristocetin to aggregate rat platelets while human platelet aggregation by human or rat F VIII R:WF was only moderately affected.

These studies show that rat F VIII R:WF can interact with rat and human platelets. The lack of response of rat platelets to ristocetin in their own plasma is most likely due to a low sensitivity of rat platelets to this drug and to an inhibitory activity of plasma proteins on this reaction.
Behaviour of Protein C Inhibitor in Intravascular Coagulation and Liver Disease
Authors: Francis R B , Thomas W
Published: July 2018

We measured levels of protein C inhibitor in patients with disseminated intravascular coagulation (DIC) and liver disease using a functional assay. Levels in 24 normal subjects averaged 93% of the amount in normal pooled plasma, giving a normal range of 65 to 121%. Levels were below normal in 8 of 17 patients with DIC, in 4 of 19 patients with liver cirrhosis, and in 3 patients with acute hepatic necrosis. Levels were normal or elevated in 9 of 10 patients with cirrhosis and accelerated fibrinolysis, and in 6 patients receiving warfarin. We conclude that protein C inhibitor may be involved in regulation of protein C activity during pathologic activation of the hemostatic system (DIC). Decreased protein C inhibitor does not appear to contribute to the pathogenesis of accelerated fibrinolysis in liver disease. The liver may be the site of synthesis of protein C inhibitor.
Intensive Initial Oral Anticoagulation and Shorter Heparin Treatment in Deep Vein Thrombosis
Authors: Schulman Sam , Lockner Dieter , Bergström Kurt , Blombäck Margareta
Published: July 2018

In order to investigate whether a more intensive initial oral anticoagulation still would be safe and effective, we performed a prospective randomized study in patients with deep vein thrombosis. They received either the conventional regimen of oral anticoagulation (“low-dose”) and heparin or a more intense oral anticoagulation (“high-dose”) with a shorter period of heparin treatment.

In the first part of the study 129 patients were randomized. The “low-dose” group reached a stable therapeutic prothrombin complex (PT)-level after 4.3 and the “high-dose” group after 3.3 days. Heparin was discontinued after 6.0 and 5.0 days respectively. There was no difference in significant hemorrhage between the groups, and no clinical signs of progression of the thrombosis.

In the second part of the study another 40 patients were randomized, followed with coagulation factor II, VII, IX and X and with repeated venograms. A stable therapeutic PT-level was achieved after 4.4 (“low-dose”) and 3.7 (“high-dose”) days, and heparin was discontinued after 5.4 and 4.4 days respectively. There were no clinical hemorrhages, the activity of the coagulation factors had dropped to the same level in both groups at the time when heparin was discontinued and no thromboembolic complications occurred.

Our oral anticoagulation regimen with heparin treatment for an average of 4.4-5 days seems safe and reduces in-patient costs.
Improved Assay Conditions for Automated Antithrombin III Determinations with the Chromogenic Substrate S-2238
Authors: Voorthuizen H van , Kluft C
Published: July 2018

Assays for antithrombin III activity using the chromogenic substrate S-2238 were automated in various modifications on various instruments. Standard curves for the assay showed a deviating “0% point” in several but not all modifications. Addition of polyethylene glycol 6000/8000 (0.40-1.0%) minimizes this deviation. However, the deviation of the 0% point was not completely abolished in every modification of the test. Examination of Lineweaver-Burk plots showed nonlinearity at high concentrations of S-2238 as used in the antithrombin III assays. Addition of Tween-80 (0.01%) restores the Lineweaver-Burk plot and, at the same time, the standard curve in the assays is found to be linear. Therefore, we recommend the use of PEG 6000/8000 as well as Tween-80 in automated assay systems.
Hemostatic Parameters in Newborn - I. Effect of Gestation and Rate of Intrauterine Growth
Authors: Dube B , Dube R K , Bhargava V , Kolindewala J K , Kota V L N , Das B K
Published: July 2018

The present study comprises of 208 term, 159 preterm and 18 post-term neonates born to mothers with no history of drug intake or any disease likely to effect coagulation of the newborn. PT, TT and KCCT were relatively prolonged and plasma fibrinogen reduced to varying degree in newborns (as compared to adults). There was further prolongation of TT and reduction in plasma fibrinogen levels amongst preterm newborns as compared to term babies; TT was more prolonged amongst post-term babies also. PT was significantly more prolonged till 30 weeks of gestation, after which a near plateau was formed. KCCT showed significant improvement after 33 weeks and a further trend to normalisation after 38 weeks of gestation. Serum FDP values showed too much of variation for any meaningful statistical analysis but generally FDPs were higher in preterm babies. Intrauterine growth rate had no significant effect on these parameters amongst preterms -similar values for SGA (small for gestational age), AGA (appropriate for gestational age) and LGA (large for gestational age). On the other hand, amongst term babies SGA neonates had significantly prolonged PT and low plasma fibrinogen as compared to AGA; LGA babies also showed more prolongation of TT as compared to AGA.
A Simple In Vitro Model of Mechanical Injury of Confluent Cultured Endothelial Cells to Study Quantitatively the Repair Process
Authors: Klein-Soyer Claude , Beretz Alain , Millon-Collard Régine , Abecassis Joseph , Cazenave Jean-Pierre
Published: July 2018

A model of in vitro mechanical injury of confluent human endothelial cells (EC) in culture was developed. Human EC were obtained from umbilical veins and grown to confluence. Application on the EC monolayer of a calibrated disk of cellulose poly acetate paper resulted in removal of the EC, leaving a continuous subendothelial extracellular matrix (ECM) on the culture dish. The regeneration time depended on the original size of the lesion. Regeneration was similar with EC grown on different substrates such as human fibronectin, human subendothelial ECM, bovine collagen type I or surfaces coated with Transglutine®, a surgical glue containing adhesive proteins. A human brain extract containing growth factor activity accelerated significantly the repair of the lesion, especially at low serum concentration. This simple in vitro model of mechanical injury allows the quantitative study of the effects of matrices, growth factors and pharmacological agents on the repair process.
Cochlear Implants and Children with Vestibular Impairments
Authors: Papsin Blake , Cushing Sharon
Published: July 2018

Sensorineural hearing loss (SNHL) in children occurs in 1 to 3% of live births and acquired hearing loss can additionally occur. This sensory deficit has far reaching consequences that have been shown to extend beyond speech and language development. Thankfully there are many therapeutic options that exist for these children with the aim of decreasing the morbidity of their hearing impairment. Of late, focus has shifted beyond speech and language outcomes to the overall performance of children with SNHL in real-world environments. To account for their residual deficits in such environments, clinicians must understand the extent of their sensory impairments. SNHL commonly coexists with other sensory deficits such as vestibular loss. Vestibular impairment is exceedingly common in children with SNHL with nearly half of children exhibiting vestibular end-organ dysfunction. These deficits naturally lead to impairments in balance and delay in motor milestones. However, this additional sensory deficit likely leads to further impairment in the performance of these children. This article focuses on the following:

1. Defining the coexistence of vestibular impairment in children with SNHL and cochlear implants.

2. Describing screening methods aimed at identifying vestibular dysfunction in children with SNHL.

3. Understanding the functional implications of this dual-sensory impairment.

4. Exploring possible rehabilitative strategies to minimize the impact of vestibular impairment in children with SNHL
Unstable spectra of double tearing modes with anti-symmetric shear flow
Authors: Nemati M. J. , Wei L. , Wang Z. X.
Published: July 2018

The linear properties of both even and odd double tearing modes (DTMs) in the presence of plasma shear flow are studied based on a reduced resistive MHD model in slab geometry. It is found that for the anti-symmetric shear flow, the linear growth rates γ(ky) of the even (odd) eigenmode of DTMs decrease (increase) with increasing the strength of shear flow. Indeed, in the small wavenumber ky regime, γ(ky) of the even eigenmode is larger than that of the odd eigenmode, while γ(ky) of two kinds of eigen states coalesce with each other (the same growth rate and opposite frequencies) when the wavenumber ky exceeds a critical value kyC. It is demonstrated that kyC decreases with decreasing η for a fixed separation between two resonant surfaces xs, while decreasing xs increases the critical value of kyC for a fixed shear velocity. In the nonlinear regime for a low value of resistivity, it is observed that by increasing the strength of anti-symmetric shear flow, in the early phase of the abrupt regime a monster plasmoid and subsidary small plasmoids are generated, and later they are ejected from the DTM current sheet and merged with the main DTM islands.
Effect of temperature on foamability using a thermoresponsive polymer
Authors: Jackman Matthew , Bussonnière Adrien , Leung Hin Long , Xu Zhenghe , Tsai Peichun Amy , Liu Qingxia
Published: July 2018

We experimentally examine foam dynamics and foamability using a thermoresponsive polymer, Poly(n-isopropylacrylamide) or PNIPAM. Under a constant gas injection, our results show that temperature significantly affects the foam height produced. A stable foam was observed at room temperature while unstable at temperature above the lower critical solution temperature. Analysis of the foam structure reveals an important increase in the coalescence rate at high temperature, thereby suggesting a change of the air-water interface properties with the temperature. The findings demonstrate the controlling ability of the PNIPAM polymer to produce thermoresponsive foams, offering beneficial applications for foaming processes and mineral flotation.
Growth mode-dependent ferromagnetic properties of palladium nanoclusters
Authors: Venäläinen A. , Jalkanen P. , Tuboltsev V. , Savin A. , Räisänen J.
Published: July 2018

Cluster deposited Pd films exhibit ferromagnetism in the temperature range from 1.8 to 400 K. The magnetization properties are found to be dependent on the film thickness. The varying morphology of the resulting Pd film with respect to thickness suggests that cluster size, deposition energy, and substrate type are crucial for the resulting film magnetization. This is demonstrated by the characteristic ferromagnetic hysteresis with the temperature dependent saturation magnetization, remanence, and coercivity of palladium nanocluster aggregates. The temperature dependence of the saturation magnetization, remanence, and coercivity of Pd nanoclusters were measured using an ultra-high-sensitive magnetometer based on a superconducting quantum interference device, and the morphology of the samples was analyzed by tunneling electron microscopy.
Nonlinear thermal and electronic optical properties of graphene in N-methylpyrrolidone at 800 nm with femtosecond laser pulses
Authors: Weigand R. , Sánchez-Balmaseda M. , Afanador-Delgado S. M. , Salavagione H. J.
Published: July 2018

Graphene is a useful saturable absorber in a variety of lasers working in mode-locking or Q-switch regimes. The optical performance of chemically synthesized graphene is still not completely characterized. In this study, the saturable absorption and the nonlinear refractive index of graphene flakes in N-methylpyrrolidone, in both liquid and solid phases, have been studied at 800 nm with the z-scan technique using femtosecond laser pulses. The results obtained using a Ti:sapphire laser oscillator in the mode-locking regime (6 fs, 78 MHz) or in the continuous wave shows that the optical properties of graphene have a thermal origin, while at the lower repetition rate and higher energy and intensity of a Ti:sapphire amplifier (95 fs, 1 kHz), it shows the electronic Kerr effect. Solid samples with very high optical densities, equivalent to 60 layers of graphene grown by chemical vapor deposition (CVD), can be fabricated. They show a higher saturation intensity (Is≈100 GW cm–2) than CVD-grown (74 MW cm–2) or epitaxially grown (4 GW cm–2) graphene and intensity-dependent changes in transmission from 25% to 43%. This change in transmission in multilayer solid samples points to a good performance as a saturable absorber in laser cavities.
Learning dynamic Boltzmann distributions as reduced models of spatial chemical kinetics
Authors: Ernst Oliver K. , Bartol Thomas , Sejnowski Terrence , Mjolsness Eric
Published: July 2018

Finding reduced models of spatially distributed chemical reaction networks requires an estimation of which effective dynamics are relevant. We propose a machine learning approach to this coarse graining problem, where a maximum entropy approximation is constructed that evolves slowly in time. The dynamical model governing the approximation is expressed as a functional, allowing a general treatment of spatial interactions. In contrast to typical machine learning approaches which estimate the interaction parameters of a graphical model, we derive Boltzmann-machine like learning algorithms to estimate directly the functionals dictating the time evolution of these parameters. By incorporating analytic solutions from simple reaction motifs, an efficient simulation method is demonstrated for systems ranging from toy problems to basic biologically relevant networks. The broadly applicable nature of our approach to learning spatial dynamics suggests promising applications to multiscale methods for spatial networks, as well as to further problems in machine learning.
Revealing instabilities in a generalized triadic supply network: A bifurcation analysis
Authors: Ritterskamp Daniel , Demirel Güven , MacCarthy Bart L. , Rudolf Lars , Champneys Alan R. , Gross Thilo
Published: July 2018

Supply networks are exposed to instabilities and thus a high level of risk. To mitigate this risk, it is necessary to understand how instabilities are formed in supply networks. In this paper, we focus on instabilities in inventory dynamics that develop due to the topology of the supply network. To be able to capture these topology-induced instabilities, we use a method called generalized modeling, a minimally specified modeling approach adopted from ecology. This method maps the functional dependencies of production rates on the inventory levels of different parts and products, which are imposed by the network topology, to a set of elasticity parameters. We perform a bifurcation analysis to investigate how these elasticities affect the stability. First, we show that dyads and serial supply chains are immune to topology-induced instabilities. In contrast, in a simple triadic network, where a supplier acts as both a first and a second tier supplier, we can identify instabilities that emerge from saddle-node, Hopf, and global homoclinic bifurcations. These bifurcations lead to different types of dynamical behavior, including exponential convergence to and divergence from a steady state, temporary oscillations around a steady state, and co-existence of different types of dynamics, depending on initial conditions. Finally, we discuss managerial implications of the results.