bluuebunny/crossref_metadata_2025 huggingface dataset:
Hypercrosslinked mesoporous poly(ionic liquid)s with high ionic density for efficient CO2 capture and conversion into cyclic carbonates
Authors: Xie Yaqiang , Liang Jun , Fu Yawen , Huang Mengting , Xu Xun , Wang Hongtao , Tu Song , Li Jun
Published: March 2018

Hypercrosslinked MPILs with high ionic density and excellent textural properties were prepared for efficient simultaneous CO2 adsorption and cycloaddition.
Synergy of a titanium chelate electron collection layer and a vertical phase separated photoactive layer for efficient inverted polymer solar cells
Authors: Bai Yiming , Yang Bo , Zhao Chunyan , Shi Zhenzhen , Hayat Tasawar , Alsaedi Ahmed , Tan Zhan'ao
Published: March 2018

Both interfacial and photoactive layers play crucial roles in efficient polymer solar cells (PSCs).
Facile template-free synthesis of uniform carbon-confined V2O3 hollow spheres for stable and fast lithium storage
Authors: Han Chunhua , Liu Fang , Liu Jinshuai , Li Qi , Meng Jiashen , Shao Bowen , He Qiu , Wang Xuanpeng , Liu Ziang , Mai Liqiang
Published: March 2018

A facile and efficient template-free method has been successfully developed to fabricate uniform nitrogen-doped carbon-confined V2O3 hollow spheres, which displayed stable and fast lithium storage.
Resistive-based gas sensors for detection of benzene, toluene and xylene (BTX) gases: a review
Authors: Mirzaei Ali , Kim Jae-Hun , Kim Hyoun Woo , Kim Sang Sub
Published: March 2018

Sensing of benzene, toluene and xylene gases using resistive-based gas sensors.
Excellent microwave absorption of lead halide perovskites with high stability
Authors: Guo Heng , Yang Jian , Pu Bingxue , Chen Haiyuan , Li Yulan , Wang Zhiming , Niu Xiaobin
Published: March 2018

Organic–inorganic CH3NH3PbI3, CH3NH3PbBr3 and CH3NH3PbCl3 perovskites possess outstanding microwave absorbability with high reflectance loss values.
Entropy‐score‐based feature selection for moment‐based SAR image classification
Authors: Bolourchi P. , Demirel H. , Uysal S.
Published: March 2018

Entropy score is defined to be a metric indicating the class separation, which is then used in feature selection process to improve the moment‐based classification performance of synthetic aperture radar (SAR) images. Feature extraction is performed over each SAR image by employing different moment methods to enrich the feature space before feature selection. Fusing all the features coming from different moment methods into a single vector is not feasible since the vector will have high dimensionality and embedded redundancies due to correlations among features. To reduce the dimensionality of feature space and increase the discrimination capability of the feature vector, a unique approach based on entropy score selecting top k methods for each feature coefficient is proposed. Experimental results verify the improvement of the accuracy on SAR image classification over the state‐of‐the‐art.
Fingerprint liveness map construction using convolutional neural network
Authors: Jung H.Y. , Heo Y.S.
Published: March 2018

With increasing markets for fingerprint authentication, there are also increasing concerns about spoofs or synthetically produced fingerprint identifications that can bypass the authentication process. In this Letter, the authors introduce a new convolutional neural networks (CNNs) architecture for fingerprint liveness detection problem that can provide a more robust framework for network training and detection than previous methods. The proposed method employs squared regression error for each receptive field without the usage of the fully connected layer. Such structure provides following advantages from the previous liveness fingerprint CNN. First, unlike the previous techniques which rely on the pre‐trained features, the proposed CNN can be trained directly from fingerprints as the loss is minimised for each receptive field. Second, in contrast to the cross‐entropy layer, the squared error layer allows them to set up a threshold value that can control the acceptable level of false positives or false negatives. Third, the absence of a fully connected layer allows them to crop the input fingerprints such that a trade‐off between accuracy and computation time can be made without the negative effects of re‐scaling. The proposed CNN is shown to provide higher accuracy for three out of four datasets when evaluated against the state‐of‐the‐art method.
Finite‐time stability of non‐linear systems with impulsive effects due to logic choice
Authors: Zhang Junhui , Sun Jitao , Wang Qing‐Guo
Published: March 2018

This study is concerned with the finite‐time stability of non‐linear systems with impulsive effects due to logic choice. Firstly, we introduce a class of non‐linear systems with logic‐induced impulses and it generalises the model established in Suo and Sun (2015). Then, based on semi‐tensor product technique, several criteria for finite‐time stability for the system are given. Finally, two numerical examples are provided to illustrate authors' results.
Synchronised trajectory tracking for a network of MIMO non‐minimum phase systems with application to aircraft control
Authors: Zhu Yang , Chen Jingyang , Zhu Bo , Qin Kai‐yu
Published: March 2018

In this study, the problem of synchronised trajectory tracking for a network of multi‐input–multi‐output (MIMO) non‐minimum phase (NMP) systems is addressed under a switching communication topology. First, an approach to convert the original system equation into a normal form is proposed, where a coordinate transformation matrix is introduced. Then, a control solution is developed, which is made up of a distributed observer network to generate an estimate of the reference system, a causal stable inversion to estimate the bounded state reference and feedforward term, and a local state‐trajectory tracker to achieve simultaneously asymptotic output tracking and internal dynamics stabilisation. Finally, the solution is applied to the synchronised flight‐path angle and velocity tracking problem of a network of F‐16 aircraft, and further compared with the classic proportional–integral–derivative control‐based approach used in many real‐life applications. Simulation results demonstrate the effectiveness of the proposed solution, as well as the performance advantages owing to a systematic consideration of the NMP property.
Cluster consensus of heterogeneous linear multi‐agent systems
Authors: Chen Kairui , Wang Junwei , Zhang Yun , Lewis Frank L.
Published: March 2018

This study addresses the cluster consensus problem for generic linear heterogeneous multi‐agent systems. The main purpose of this study is to unveil how agents confront the effects of intra‐cluster couplings and inter‐cluster couplings, and reach cluster consensus. For the semi‐heterogeneous case, where agents in the same cluster have identical dynamics, cluster consensus is achieved if each agent suppresses the inter‐cluster couplings. For the heterogeneous case, where all agents have different dynamics, cluster consensus is achieved if each agent confronts both inter‐cluster and intra‐cluster couplings. Two kinds of control protocols using relative output errors are designed for the heterogeneous case. For both semi‐heterogeneous and heterogeneous cases, design procedures are provided to construct controllers to satisfy the relation between the dynamics of agents and the communication graph, which ensure cluster consensus. Finally, numerical examples are provided to verify the theoretical results.
Action recognition based on motion of oriented magnitude patterns and feature selection
Authors: Phan Hai‐Hong , Vu Ngoc‐Son , Nguyen Vu‐Lam , Quoy Mathias
Published: March 2018

Here, the authors introduce a novel system which incorporates the discriminative motion of oriented magnitude patterns (MOMP) descriptor into simple yet efficient techniques. The authors’ descriptor both investigates the relations of the local gradient distributions in neighbours among consecutive image sequences and characterises information changing across different orientations. The proposed system has two main contributions: (i) the authors adopt feature post‐processing principal component analysis followed by vector of locally aggregated descriptors encoding to de‐correlate MOMP descriptor and reduce the dimension in order to speed up the algorithm; (ii) then the authors include the feature selection (i.e. statistical dependency, mutual information, and minimal redundancy maximal relevance) to find out the best feature subset to improve the performance and decrease the computational expense in classification through support vector machine techniques. Experiment results on four data sets, Weizmann (98.4%), KTH (96.3%), UCF Sport (82.0%), and HMDB51 (31.5%), prove the efficiency of the authors’ algorithm.
Visual multiple‐object tracking for unknown clutter rate
Authors: Kim Du Yong
Published: March 2018

In multi‐object tracking applications, model parameter tuning is a prerequisite for reliable performance. In particular, it is difficult to know statistics of false measurements due to various sensing conditions and changes in the field of views. In this study, the authors are interested in designing a multi‐object tracking algorithm that handles unknown false measurement rate. The recently proposed robust multi‐Bernoulli filter is employed for clutter estimation while generalised labelled multi‐Bernoulli filter is considered for target tracking. Performance evaluation with real videos demonstrates the effectiveness of the tracking algorithm for real‐world scenarios.
Deadbeat control based on a multipurpose disturbance observer for permanent magnet synchronous motors
Authors: Yang Haitao , Zhang Yongchang , Liang Jiejunyi , Xia Bo , Walker Paul D. , Zhang Nong
Published: March 2018

Robustness against parameter mismatches and position‐sensorless operation are two important research topics for permanent magnet synchronous motor (PMSM) drives. Usually, the existing observers are designed for achieving a specific function. While here, both the above two functions are integrated into the proposed sliding‐mode disturbance observer: (i) if a position sensor is equipped, accurate current regulation can be achieved by deadbeat predictive current control despite mismatched motor parameters; (ii) if the position sensor is not equipped but with a good estimation of motor parameters, the observer can serve as a back electromotive force estimator. Then, the rotor position can be extracted for position‐sensorless control. Usually, a low‐pass filter is required to suppress high‐frequency noises in the conventional sliding‐mode observer. This inevitably leads to phase delay in the estimation. By comparison, a complex coefficient filter is inherently embedded in the proposed method, which can provide accurate estimation without phase delay or magnitude error. Experimental results obtained from a 2.4 kW PMSM drive platform indicate that high‐performance current control can be achieved with good robustness for position sensor‐based operation. Also, rotor position can be accurately estimated with good steady and dynamic performance for position‐sensorless operation.
Virtual DC machine: an inertia emulation and control technique for a bidirectional DC–DC converter in a DC microgrid
Authors: Samanta Soumya , Mishra Jyoti Prakash , Roy Binoy Krishna
Published: March 2018

In a DC microgrid (DCMG), the DC bus voltage is vulnerable to the power fluctuations caused by the variations of intermittent renewable energy sources and local loads. A concept is developed to operate a bidirectional DC–DC converter as a DC machine to mimic the inertia characteristic of a DC machine and regulate the DC bus voltage fluctuations during power fluctuations of the DCMG. The concept of operating a bidirectional DC–DC converter as a DC machine can be termed as virtual DC machine (VDCM). The proposed concept of a VDCM is basically a control technique for a bidirectional DC–DC converter, which is derived from the theory of the DC machine operation and its speed control technique. The implementation, operation, controller design and dynamics of VDCM are also discussed. A VDCM can be easily operated in both generating and motoring mode also. Being free from comparatively slower mechanical devices, a VDCM can switch over from one mode to another very quickly. Hence, it provides a useful way to control the storage devices in microgrid applications.
Inter‐turn fault diagnosis of permanent magnet synchronous machine based on tooth magnetic flux analysis
Authors: Zeng Chong , Huang Song , Yang Yongming , Wu Dun
Published: March 2018

This study proposes a novel inter‐turn fault diagnosis method for a permanent magnet synchronous machine. Search coils are set on every stator tooth to measure the tooth fluxes. The high‐order harmonics produced by the inverter are adopted to diagnose the inter‐turn fault existence and locate the fault tooth. The fault severity coefficient is proposed on the basis of theoretical analysis and can identify the fault severity. A comparative analysis of a traditional method based on co‐simulation shows that the proposed method is sensitive and that the fault severity coefficient is accurate, intuitive and independent of the operating condition of the motor. An experimental platform is set up, and it validates the effectiveness of the proposed method.
Understanding the effects of peripheral vision and muscle memory on in‐vehicle touchscreen interactions
Authors: Eren Ayse Leyla , Burnett Gary , Large David R , Harvey Catherine
Published: March 2018

It is important to gain a better understanding of how drivers interact with in‐vehicle touchscreens to help design interfaces to minimise ‘eyes‐off‐road’ time. The study investigated the relative effects of two interaction mechanisms (peripheral vision – PV, muscle memory – MM) shown to be relevant to visual behaviour when driving, on the time to press different sized buttons (small 6 × 6 cm, medium 10 × 10 cm, large 14 × 14 cm) on an in‐vehicle touchscreen. Twenty‐five participants took part in a driving simulator study and were presented with a single, white, square button on 24 successive trials. For MM conditions, participants wore a pair of glasses blocking their PV and for PV conditions, they were asked to keep their focus on the vehicle ahead. Results showed that task time gradually decreased when participants could only use MM. However, overall task time for MM conditions were significantly higher than PV conditions. Participants rated the use of MM to be more difficult than PV. In contrast, results suggest that for interfaces that utilise peripheral visual processing, the learning effect is not evident and operation times are constant over time. These findings indicate that in‐vehicle touch screens should be designed to utilise PV for making simple button selections with reduced visual demand.
General mathematical model for the calculation of economic cross sections of cables for wind farms collector systems
Authors: Đorđević Ana , Đurišić Željko
Published: March 2018

A model for calculation of the economic cross sections of cables within the internal network of a wind farm is presented. The economic cross sections of the internal wind farm cables provide maximisation of the profit generated by the wind farm within its life‐span through an optimisation of the balance between the investment and operating costs. This study presents a practical mathematical model for determining the optimal cable cross section based on: the wind statistics at the wind turbine location, wind turbine power curve, price of the electric energy, price of the cable, and interest rate. By using the developed model in the planning phase of a wind farm project each of the connection feeders within the internal cable network can be optimised. The proposed model is demonstrated by the example of a perspective wind farm with a rated power of 25 MW located in the region of Banat, Serbia. The calculations done for the observed wind farm show that the optimisation of the interconnecting cable cross sections makes profit increase of nearly 1 million Euro, compared to the model for the calculation of cable cross sections based only on technical limitations.
SFMM design in colocated CS‐MIMO radar for jamming and interference joint suppression
Authors: Xiong Wei , Greco Maria , Gini Fulvio , Zhang Gong , Peng Zhenni
Published: March 2018

This study focuses on the problem of joint suppression of active jamming in target sector‐of‐interest (SOI) and out‐of‐sector interference for colocated compressive sensing multiple‐input–multiple‐output (CS‐MIMO) radar. Three effective strategies for spatial filter measurement matrix (SFMM) design are outlined. Unlike the previous reported Capon beamformer and minimum variance distortionless response beamformer, the proposed design strategies only depend on the target spatial SOI rather than the accurate directions‐of‐arrival (DOAs) of targets, jammers and interfering sources to obtain deep nulls or notches for the SOI jamming and low‐attenuation levels for the out‐of‐sector interference. The SFMM design criteria are derived using the second‐order cone programming and solved as convex optimisation problems. The proposed approaches can simultaneously suppress the SOI jamming and attenuate the out‐of‐sector interference. Meanwhile, better DOA estimation accuracy can be achieved. Simulation results demonstrate the superiority of the proposed approaches over the other methods for colocated CS‐MIMO radar.
Multi‐baseline InSAR phase unwrapping method based on mixed‐integer optimisation model
Authors: Jin Biao , Guo Jiao , Wei Pengliang , Su Baofeng , He Dongjian
Published: March 2018

Multi‐baseline phase unwrapping operation is a very important step for multi‐baseline Synthetic Aperture Radar Interferometry (InSAR). However, the conventional methods applied for single pixel suffer seriously from the phase noise that exists numerously in the interferometric phase images (i.e. interferograms). In order to improve the robustness to noise, this study proposes an innovative multi‐baseline InSAR phase unwrapping method based on a mixed‐integer optimisation model. The proposed method combines the central and its neighbouring pixels to jointly construct the mixed‐integer optimisation model under the assumption that the pixels within a local window can be approximated by a small slant plane terrain. Furthermore, considering the practical case, the optimal window size is estimated according to the deviation from the interferometric wrapped phase to the assumed linear terrain, and the fast Fourier transform technique is adopted to reduce computational cost. The theoretical analysis and computer simulation demonstrate that the proposed method is able to improve the multi‐baseline phase unwrapping performance and can be applied to reconstruct the digital elevation models for complicated topographies.
Sea‐surface weak target detection scheme using a cultural algorithm aided time‐frequency fusion strategy
Authors: Cai Zhaohui , Zhang Min , Liu Yujiao
Published: March 2018

To improve the sea‐surface weak targets detection performance of the marine surface surveillance radar systems, the authors put forward a novel detection scheme based on a time‐frequency distribution (TFD) fusion strategy assisted by population evolution algorithm. A Volterra‐series‐based weighted averaging model is utilised as the fusion rule to construct the fused TFD (FTFD), which aims to enhance the performance of time‐frequency (TF) analysis and suppress signal‐dependent cross‐term artefacts. Herein, the optimal fusion coefficient is estimated by culture‐based population evolutionary algorithm without any prior information. Unfortunately, this FTFD produces a great deal of redundant information. Hence, the normalised frequency marginal feature is extracted to reduce dimensions of the TF discriminant features, which is necessary to improve the efficiency of pattern classification. Finally, a multi‐layered feed‐forward neural network is utilised as a classifier in the pattern classification process. Experimental results demonstrate that the FTFD constructed by the proposed scheme achieves better performance in sharpness and strength than any subset of TFDs or their combinations and, furthermore, increases the detectability of sea‐surface floating weak targets under any environment circumstances.
Abnormal event detection based on cosparse reconstruction
Authors: Chen Huahua , Gai Jie , Zhang Song , Wang Chao , Guo Chunsheng , Ye Xueyi , Lu Yu
Published: March 2018

A novel video abnormal event detection method based on cosparse reconstruction with local self‐similarity constraint is proposed. For a given spatio‐temporal patch which is represented by a feature vector using concatenated multi‐scale histogram of optical flow, abnormal event detection is implemented by cosparse reconstruction with respect to an analysis dictionary learned from normal event set. To adapt to the diversity of normal events, feature space is partitioned into meaningful subspaces by clustering and cosparse sub‐dictionary is learned from each cluster. Experimental results show that the proposed approach achieves competitive performance with the state‐of‐the‐art methods.
A new X-ray look into four old pulsars
Authors: Rigoselli Michela , Mereghetti Sandro
Published: March 2018

We report on the X-ray properties of four rotation-powered pulsars with characteristic ages in the range 0.3–5 Myr, derived from the analysis of XMM–Newton archival observations. We found convincing evidence of thermal emission only in the phase-averaged spectrum of PSR B0114+58, which is well fitted by a blackbody with temperature kT = 0.17 ± 0.02 keV and emitting radius R = 405+110−90 m, consistent with the size of its polar cap. The three other considered pulsars, PSR B0628−28, PSR B0919+06, and PSR B1133+16, have phase-averaged spectra that can be described well by single power laws with photon index Γ ~ 3. The 3σ upper limits on the bolometric luminosity of a possible thermal component with temperatures in the range ~0.05−2 keV are Lbol ≲ 3.2 × 1028 erg s−1 and Lbol ≲ 2.4 × 1029 erg s−1, for PSR B0628−28 and PSR B0919+06, respectively. On the other hand, we found possible evidence that the pulsed emission of PSR B0628−28 is thermal. Two absorption lines at ~0.22 keV and ~0.44 keV are detected in the spectrum of PSR B1133+16. They are best interpreted as proton cyclotron features, implying the presence of multipolar components with a field of a few 1013 G at the neutron star polar caps. We discuss our results in the context of high-energy emission models of old rotation-powered pulsars.
Experimental validation of joint phase and amplitude wave-front sensing with coronagraphic phase diversity for high-contrast imaging
Authors: Herscovici-Schiller O. , Mugnier L. M. , Baudoz P. , Galicher R. , Sauvage J.-F. , Paul B.
Published: March 2018

Context.The next generation of space-borne instruments dedicated to the direct detection of exoplanets requires unprecedented levels of wavefront control precision. Coronagraphic wavefront sensing techniques for these instruments must measure both the phase and amplitude of the optical aberrations using the scientific camera as a wavefront sensor.

Aims.In this paper, we develop an extension of coronagraphic phase diversity to the estimation of the complex electric field, that is, the joint estimation of phase and amplitude.

Methods.We introduced the formalism for complex coronagraphic phase diversity. We have demonstrated experimentally on the Très Haute Dynamique testbed at the Observatoire de Paris that it is possible to reconstruct phase and amplitude aberrations with a subnanometric precision using coronagraphic phase diversity. Finally, we have performed the first comparison between the complex wavefront estimated using coronagraphic phase diversity (which relies on time-modulation of the speckle pattern) and the one reconstructed by the self-coherent camera (which relies on the spatial modulation of the speckle pattern).

Results.We demonstrate that coronagraphic phase diversity retrieves complex wavefront with subnanometric precision with a good agreement with the reconstruction performed using the self-coherent camera.

Conclusions.This result paves the way to coronagraphic phase diversity as a coronagraphic wave-front sensor candidate for very high contrast space missions.
The Effect of Fibrinogen Genotype on Fibrinogen Levels after Strenuous Physical Exercise
Authors: Dhamrait S. , Moulding R. , Rumley A. , Lowe G. D. O. , World M. J. , Humphries S. E. , Montgomery H. E. , Brull D.J.
Published: March 2018

We have examined the effect of two f3-fibrinogen gene promoter polymorphisms (-455G>A and -854G>A) on the fibrinogen response to severe exercise in a group of male army recruits undergoing basic training. Fibrinogen was measured pre-training and again serially after severe 48 h final military exercise (FME). Out of 884 subjects, 762 completed training of whom 250 were selected for post-FME study. Fibrinogen levels (g/l) were significantly elevated over baseline levels 2, 48 and 96 h after FME, representing increases of 15.7%, 3.4% and 7.6% (p <0.005; p = 0.05 and p <0.005 respectively), with higher levels in -455A allele carriers than genotype -455GG: 3.17 ± 0.05 vs. 2.94 ± 0.05 (p <0.001), 2.86 ± 0.05 vs. 2.60 ± 0.05 (p <0.0005) and 2.98 ± 0.06 vs. 2.69 ± 0.06 (p <0.0005) at 2, 48 and 96 h respectively. There was no effect of the -854G>A polymorphism on fibrinogen, even after taking into account f3-fibrinogen -455 genotype. Thus the fibrinogen -455G>A polymorphism influences fibrinogen levels following exercise. The effect of genotype might be clinically relevant at times of hyperfibrinogenaemia such as following an acute inflammatory response.
D-Dimer as a Risk Factor for Deep Vein Thrombosis: The Leiden Thrombophilia Study
Authors: Andreescu Astrid , Rosendaal Frits , Cushman Mary
Published: March 2018

We studied the association of D-dimer with the risk of deep vein thrombosis (DVT). D-dimer was measured in 474 patients more than 6 months after diagnosis of a first DVT and in 474 age-and sexmatched controls. For D-dimer above the 70th percentile (130.5 ng/ml), the odds ratio (OR) for DVT was 2.2 (95% CI, 1.6-2.9). The association was unchanged with adjustment for other risk factors. Excluding participants with Factor V Leiden, prothrombin 20210A, or factors VIIIc or IX above the 90th percentile, the OR was 1.6 (95% CI, 1.1-2.3). The risks of DVT with the joint presence of high D-dimer and either factor V Leiden or prothrombin 20210A were increased 12.4-fold (95% CI 5.6-27.7) and 7.2-fold (95% CI 2.1-25.1), respectively. Higher Ddimer concentration was associated with the risk of DVT, and was supra-additive to the risks associated with factor V Leiden and the prothrombin 20210A variant. Persistence of this association in the absence of other hemostatic risk factors for DVT suggests that high D-dimer may be related to other, as yet unknown, risk factors for venous thrombosis. Confirmation of these findings is desirable.
Physical and Functional Interaction Between Cell-Surface Calreticulin and the Collagen Receptors Integrin α2β1 and Glycoprotein VI in Human Platelets
Authors: Elton Catherine , Smethurst Peter , Eggleton Paul , Farndalerd Rich
Published: March 2018

Calreticulin is an abundant protein in the endoplasmic reticulum of most cells. In this study, flow cytometry and immunoprecipitation from surface-biotinylated platelets each provided direct evidence that calreticulin is also expressed on the surface of human platelets. Anti-calreticulin antibodies caused platelet activation, inducing Fc RIIa-independent platelet aggregation. In addition, these antibodies inhibited platelet adhesion to the integrin α2β1-specific ligands, GFOGER-GPP and monomeric collagen I, and to the glycoprotein VI-specific ligand, CRP. Inhibition of platelet adhesion to these ligands was independent of integrin αIIbβ3. In resting platelets, calreticulin was shown to interact with integrin α2β1 and glycoprotein VI. Together, these data demonstrate that surface calreticulin is associated with collagen receptors on the platelet surface, where it may play a role in the modulation of the platelet-collagen interaction.

Abbreviations: BSA: bovine serum albumin; cC1qR: complement component
1q receptor; CRP: collagen-related peptide; DTSSP: 3,3’-dithiobis (sulfosuccinimidyl propionate); ER: endoplasmic reticulum; GFOGER-GPP: GPC[GPP]5GFOGER[GPP]5GPC; GpVI: glycoprotein VI; HRP: horseradish peroxidase; PDI: protein disulfide isomerase.
Erythropoietin Triggers a Signaling Pathway in Endothelial Cells and Increases the Thrombogenicity of their Extracellular Matrices In Vitro
Authors: Fusté Berta , Serradell Mireia , Escolar Ginés , Cases Aleix , Mazzara Roberto , Castillo Ricardo , Ordinas Antonio , Díaz-Ricart Maribel
Published: March 2018

We demonstrate that exposure of cultured human endothelial cells to rHuEPO resulted in a dose-dependent increase in the tyrosine kinase activity, with phosphorylation of JAK-2 followed by rapid phosphorylation of STAT-5. Simultaneously, rHuEPO induced long-lasting phosphorylation of MAPK p42/44. Activation of this signaling pathways was directly associated with an increase in the thrombogenic properties of the extracellular matrix generated by these cells, when they were exposed to flowing blood. The enhancement in the reactivity of the resulting extracellular matrix towards platelets was associated with a higher expression of tissue factor. All these effects were blocked by an antibody to the EPO receptor and by specific inhibitors of tyrosine phosphorylation. The observed action of rHuEPO on endothelial cells seemed to be specifically triggered by the subsequent events that follow receptor binding, and occurred even at pharmacological concentrations of the cytokine. Our results indicate that rHuEPO has a direct action on the endothelium, increasing the reactivity of the underlying extracellular matrix towards platelets, effect that may be attributed to an increase in the expression of TF.
NFκB is an Essential Intermediate in the Activation of Endothelial Cells by Anti-β2-Glycoprotein 1 Antibodies
Authors: Dunoyer-Geindre Sylvie , de Moerloose Philippe , Galve-de Rochemonteix Béatrix , Reber Guido , Kruithof Egbert
Published: March 2018

Antiphospholipid antibodies (aPLA) are associated with thrombophilia and recurrent pregnancy loss. They bind directly to anionic phospholipids or via phospholipid-binding proteins such as β2-glycoprotein 1 (β2GP1). The underlying mechanisms by which aPLA induce a thrombophilic phenotype are not well understood.

The present work was done to determine whether antibodies to β2GP1 activate endothelial cells (EC) and whether NFκB is involved in this activation. Incubation of EC with these antibodies resulted in a redistribution of NFκB from the cytoplasm to the nucleus after a delay of several hours. This was accompanied by an increased expression of tissue factor and of the leukocyte adhesion molecules ICAM-1, VCAM-1 and E-selectin. Inhibition of the nuclear translocation of NFκB abolished the response to these antibodies. In comparison to anti-β2GP1 antibodies, incubation of EC with TNF resulted in a more rapid (within 30 minutes) redistribution of NFκB and a more pronounced expression of tissue factor and of the leukocyte adhesion molecules. The slower response to the antibodies as compared to TNF suggests that the NFκB response to anti-β2GP1 antibodies is indirect.

Taken together our results imply that NFκB is an essential intermediate in the activation of EC by anti-β2GP1 antibodies.
Intracranial Hemorrhage in Systemic Lupus Erythematosus Associated with an Autoantibody against Factor XIII
Authors: Velasco Pauline , Hill John , Hoffmeister Karen , Kaye Fredric , Lorand Laszlo
Published: March 2018

Intracranial hemorrhage in a young woman with systemic lupus erythematosus necessitated two surgical evacuations. In the absence of a family history of bleeding, clot solubility in urea suggested a factor XIII (FXIII) inhibitor. The patient’s IgG bound well to the virgin and the thrombin-modified zymogen ensemble (A2B2 and A2’B2) and to the free rA2 but reacted poorly with the thrombin-modified rA2’. Since the IgG did not block the thrombin-catalyzed proteolysis of A subunits nor the dissociation of the A2’B2, its action might be to interfere with the release of activation peptides from the thrombincleaved zymogen, hindering the conformational change necessary for generating FXIIIa.

Treatment with cryoprecipitate and cyclophosphamide arrested the hemorrhage and almost neutralized the antibody so that the patient’s clot became insoluble in urea and showed a close to normally cross-linked γ-γ and αn fibrin chain profile. Nevertheless, she still has detectable anti-FXIII antibody and may be at risk for hemorrhage.
The effect of ß-receptor blockade on factor VIII levels and thrombin generation in patients with venous thromboembolism
Authors: Schönauer Verena , Giannini Sandra , Christ Günter , Quehenberger Peter , Bieglmayer Christian , Stain Milena , Weltermann Ansgar , Kyrle Paul
Published: March 2018

High factor VIII (FVIII) is a risk factor for venous thromboembolism (VTE). The pathomechanism by which high FVIII leads to an increased risk of VTE is unknown. Physical activity and infusion of adrenalin provoke a rise in FVIII, which can be blocked by a nonselective β-blockade. We tested the hypothesis that in patients with a VTE β-blockade decreases FVIII and inhibits coagulation activation.

17 male patients with high FVIII (> 170 IU/dL, n = 7) or low FVIII (<150 IU/dL, n = 10) and a history of VTE received 40 mg of propranolol thrice daily for 14 days. FVIII and vasopressin levels were measured before and during propranolol intake and 28 days thereafter. At the same time points, haemostatic system activation was investigated by measuring prothrombin fragment f1.2 (f1.2) and thrombin antithrombin complexes (TAT) in venous blood and in blood emerging from a skin incision (shed blood).

The mean FVIII level before propranolol was 192 IU/dL and 115 IU/dL in patients with high and low FVIII, respectively. During and 28 days after propranolol, no significant change in FVIII was seen in both groups. Changes in f1.2 and TAT were not detectable in either venous blood or in shed blood.

β-receptor blockade did not lower FVIII or inhibit haemostatic system activation in patients with VTE and persistently high FVIII. Administration of propranolol cannot be recommended as secondary thromboprophylaxis in patients with high FVIII.
The Impact of the Glycoprotein Ia Collagen Receptor Subunit A1648G Gene Polymorphism on Coronary Artery Disease and Acute Myocardial Infarction
Authors: Gardemann Andreas , Fechter Andreas , Haberbosch Werner , Santoso Sentot , Kroll Hartmut
Published: March 2018

Platelet glycoprotein (GP) Ia is the major receptor for collagen and plays an important role in platelet adhesion and aggregation. Different gene polymorphisms have been identified that induce either various expression levels (C807T) or alterations of the tertiary structure (A1648G) of GPIa. Previously, we could demonstrate an association of the GPIa C807T dimorphism with nonfatal myocardial infarction. We have now analysed the influence of the GPIa A1648G (Br, HPA-5) dimorphism on the risk of coronary artery disease (CAD) and acute myocardial infarction (AMI). DNA samples from 2163 male Caucasian patients who underwent coronary angiography were genotyped by polymerase chain reaction and restriction fragment length analysis. The relation of the GPIa A1648G dimorphism to the extent of CAD was determined by multiple regression analysis with adjustment for coronary risk factors. Odds ratios (OR) as an estimate of relative risk of CAD and AMI and two-tailed p-values were calculated by multiple logistic regression. In the total study sample, no association was detected between the A1648G dimorphism and CAD or AMI. However, upon analysis of low-risk patient subgroups we found an association of the GPIa A1648G polymorphism with the risk and the extent of CAD (patients with high apoAI/apoB ratio: OR 0.59, p = 0.0090; nonand ex-smokers: OR 0.66, p = 0.0131; both inclusion criteria: OR 0.44, p = 0.0003). The relative frequency of the A1648 allele was higher in controls whereas the GG1648 genotype was overrepresented in patients with CAD. This association was also detectable when individuals with low expression levels of GPIa (C807 homozygotes) were analysed (patients with high apoAI/apoB ratio: OR 0.44, p = 0.0045; nonand ex-smokers: OR 0.61, p = 0.0370). Our findings indicate that the A1648G polymorphism of the platelet collagen receptor plays a role in CAD in well defined patient groups.
Neuroprotection by Recombinant Thrombomodulin
Authors: Taoka Yuji , Uchiba Mitsuhiro , Johno Masayoshi , Okajima Kenji
Published: March 2018

We examined whether recombinant human soluble thrombomodulin (rhs-TM) reduces compression trauma-induced spinal cord injury through protein C activation in rats. Administration of rhs-TM, either before or after the induction of spinal cord injury (SCI), markedly reduced the resulting motor disturbances. However, neither rhs-TM pretreated with an anti-rhs-TM monoclonal antibody (MAb) F2H5, which inhibits thrombin binding to rhs-TM, nor those pretreated with MAb R5G12, which selectively inhibits protein C activation by rhsTM, prevented the motor disturbances. Intramedullary hemorrhages, observed 24 h after trauma, were significantly reduced in animals given rhs-TM. The increase in the tissue levels of tumor necrosis factor-α (TNF-α), TNF-α mRNA expression, and the accumulation of leukocytes in the damaged segment of the spinal cord were significantly inhibited in animals receiving rhs-TM, but these effects were not observed following administration of rhs-TM pretreated with MAb R5G12 or MAb F2H5. Leukocytopenia and activated protein C all produced effects similar to those of rhs-TM.

These findings suggest that rhs-TM prevents compression traumainduced SCI by inhibiting leukocyte accumulation by reducing the expression of TNF-α mRNA and such therapeutic effects of rhs-TM could be dependent on its protein C activation capacity. Findings further suggest that thrombomodulin can be implicated not only in the coagulation system but in regulation of the inflammatory response.
Rapid Change of Platelet Aggregability in Acute Hyperglycemia
Authors: Sakamoto Tomohiro , Kawano Hiroaki , Hirai Nobutaka , Miyamoto Shinzo , Takazoe Keiji , Soejima Hirofumi , Kugiyama Kiyotaka , Yoshimura Michihiro , Yasue Hirofumi , Ogawa Hisao
Published: March 2018

We examined the alteration of platelet aggregability in acute hyperglycemia during 75-gram oral glucose tolerance tests (OGTT). Twenty subjects underwent 75-gram OGTT and venous blood samples were obtained before (0 min), 60, 120 and 180 min postload. Platelet aggregability shown as the number of small platelet aggregates was measured with a novel laser-light scattering (LS) method. Platelet aggregability increased in parallel with both glucose and immunoreactive insulin (IRI) levels. The number of mean small aggregates at 60 min (12.30 ± 1.10 × 104) was significantly higher than the one at 0 min (8.32 ± 0.88 × 104, p <0.001), 120 min (10.63 ± 0.98 × 104, p <0.05) and 180 min (8.28 ± 0.84 × 104, p <0.001) (mean ± SEM). Small aggregates correlated positively with plasma glucose levels at 60 min postload (r = 0.67, p = 0.001) while not with IRI. It might be important to suppress transient hyperglycemia for preventing the onset of acute coronary syndromes that could be closely related to platelet hyperaggregability.
A Prospective Controlled Trial Comparing Weekly Self-testing and Self-dosing with the Standard Management of Patients on Stable Oral Anticoagulation
Authors: Forberg E. , Svolba G. , Jimenez-Boj E. , Krinninger B. , Watzke H. H.
Published: March 2018

Oral anticoagulant therapy requires frequent laboratory controls of its intensity to assure therapeutic efficacy and to prevent potentially life threatening adverse events. It is generally assumed, that increasing the frequency of testing would lead to a better control of anticoagulation. We tested this hypothesis in a prospective controlled trial comparing weekly self-testing and self-dosing (self management) with the standard-management of these patients in an anticoagulation clinic. Only patients with stable anticoagulation were included into the study. We recorded 2733 weekly determinations of the intensity of anticoagulation (INR) in 49 patients on self-testing and self-dosing and 539 determinations of the INR in 53 patients on standard-management. Two intensities of anticoagulation were used in each group: a target INR of 3.5 for patients with artificial heart valves (target range: 2.5–4.5) and a target INR 2.5 (target range: 2.0–3.0) for patients with atrial fibrillation or venous thromboembolism. The deviation from the target INR, the fraction of INR determinations within the preset therapeutic range and the difference between the target INR and the actually achieved mean INR were the three major endpoints of the study. The mean deviation from the target INR was smaller in the groups of patients on self–management compared to the patients on standard-management. Individual deviations were significantly (p <0.0001) dependent on the type of management in interaction with the treatment intensity in a general linear model. Patients on weekly self-testing and self-dosing had more INR values within the therapeutic range than patients on standard-management (86.2% vs. 80.1% at INR range 2.5–4.5; 82.2 vs. 68.9 at INR range 2.0–3.0). The achieved mean INR was almost identical with the target INR in the patients on self-management but was significantly (p <0.005) below the target INR in the high intensity anticoagulation group on standard-management (target INR:3.5; achieved mean INR: 3.19; CI 0.95: 3.05–3.34).

Our data show, that weekly self-testing and self-dosing leads to a better control of anticoagulation than standard treatment in an anticoagulation clinic.

The technical equipment used for self testing in this study was provided by Roche Diagnostics, Austria
Gestational Outcome in Thrombophilic Women with Recurrent Pregnancy Loss Treated by Enoxaparin
Authors: Hoffman R. , Blumenfeld Z. , Weiner Z. , Younis J. S. , Brenner B.
Published: March 2018

Inherited and acquired thrombophilia are associated with recurrent pregnancy loss (RPL). We have evaluated the efficacy and safety of the low molecular weight heparin enoxaparin in 50 women, (mean age 26 ± 3 years) with RPL (>3 losses in 1st, >2 losses in 2nd and >1 loss in 3rd trimester) who were found to harbor thrombophilia. Twentyseven had a solitary thrombophilic defect, and twenty-three women had combined thrombophilic defects: 17 – two defects and 6 – three defects. Following diagnosis of thrombophilia, sixty-one subsequent pregnancies were treated with the low molecular weight heparin enoxaparin throughout gestation until 4 weeks after delivery. Dosage was 40 mg/day in women with solitary defect and 80 mg/day in combined defects. Aspirin, 75 mg daily was given in addition to enoxaparin to women with antiphospholipid syndrome. Forty-six out of 61 (75%) gestations treated by enoxaparin resulted in live birth compared to only 38/193 (20%) of the untreated pregnancies in these 50 women prior to diagnosis of thrombophilia (p <0.00001). In 23 women without a single living child following 82 untreated gestations, antithrombotic therapy resulted in 26/31 (84%) successful deliveries (p <0.0001). In 20 women with a prior living child, antithrombotic therapy improved successful delivery from 33/86 (38%) to 20/21 (95%) (p <0.0001). Enoxaparin dose of 40 mg/day resulted in live birth in 24/35 (69%) of gestations, compared to 19/23 (83%) gestations in women treated with 80 mg/day (p = 0.37). Only one thrombotic episode and one mildbleeding episode were noticed during enoxaparin therapy. Enoxaparin is safe and effective in prevention of pregnancy loss in women with inherited and acquired thrombophilia.
High Molecular Weight Kininogen Is Cleaved by FXIa at Three Sites: Arg409-Arg410, Lys502-Thr503 and Lys325-Lys326
Authors: Mauron T. , Lämmle B. , Wuillemin W. A.
Published: March 2018

We investigated the cleavage of high molecular weight kininogen (HK) by activated coagulation factor XI (FXIa) in vitro. Incubation of HK with FXIa resulted in the generation of cleavage products which were subjected to SDS-Page and analyzed by silverstaining, ligandblotting and immunoblotting, respectively. Upon incubation with FXIa, bands were generated at 111, 100, 88 kDa on nonreduced and at 76, 62 and 51 kDa on reduced gels. Amino acid sequence analysis of the reaction mixtures revealed three cleavage sites at Arg409-Arg410, at Lys502-Thr503 and at Lys325-Lys326. Analysis of HK-samples incubated with FXIa for 3 min, 10 min and 120 min indicated HK to be cleaved first at Arg409-Arg410, followed by cleavage at Lys502-Thr503 and then at Lys325-Lys326.

In conclusion, HK is cleaved by FXIa at three sites. Cleavage of HK by FXIa results in the loss of the surface binding site of HK, which may constitute a mechanism of inactivation of HK and of control of contact system activation.
Detection of Complement-fixing Antiphospholipid Antibodies in Association with Thrombosis
Authors: Saito Takako , Matsuda Kumiko , Seino Jin , Shibata Shinobu , Sasaki Takeshi , Munakata Yasuhiko
Published: March 2018

Antiphospholipid antibody (aPL) is a hallmark of antiphospholipid syndrome (APS), characterized by thrombosis and recurrent fetal loss. We developed a novel ELISA system to detect complement-fixing ability of anticardiolipin antibody (aCL), and evaluated its clinical usefulness through studying the prevalence of the antibodies in rheumatic diseases, especially in association with thrombosis and recurrent abortion. Among 189 patients with rheumatic diseases, the complement-fixing aCL was positive in 26 (83.9%) of 31 patients with APS and 2 (1.3%) of 158 with other disease categories, whereas it was not positive among 52 normal subjects. Twenty-seven of 28 patients (96.4%), who were positive for complement-fixing aCL, had the episodes or history of thrombosis and/or recurrent abortion, at the time we studied. The remaining one in this group developed APS manifesting pulmonary infarction and occlusion of mesenteric artery 6 months after the evaluation. The sensitivity and specificity of this assay system were 75.0% and 99.3%, respectively, in relation with thrombotic episodes. On the other hand, the IgG aCL were positive in 28 (77.8%) of 36 cases with recent thrombotic episodes and 24 (15.7%) of 153 cases with no recent thrombotic episodes. The sensitivity and specificity of IgG aCL assay system were 77.8% and 84.3%, respectively, in relation with thrombotic episodes. These results indicate that complement-fixing aCL may specifically occur in association with the episodes of thrombosis and/or recurrent abortion in patients with APS compared to IgG-aCL. The method for detecting the complement-fixing aCL is simple, and it provides the useful diagnostic marker for thrombotic manifestations associated with APS.