bluuebunny/crossref_metadata_2025 huggingface dataset:
Additive Effect of the Combined Administration of Low Molecular Weight Heparin and Recombinant Hirudin on Thrombus Growth in a Rabbit Jugular Vein Thrombosis Model
Authors: Biemond Bart J , Levi Marcel , Nurmohanned Michael T , Büller Harry R , ten Cate Jan W
Published: July 2018

Recombinant Hirudin (r-Hirudin) is a new anticoagulant with specific antithrombin activity independently of antithrombin III. Low molecular weight heparins (LMWH) exert predominantly anti-Xa activity. Therefore, we hypothesized that combined administration of r-Hirudin and LMWH would induce a stronger antithrombotic effect as compared to r-Hirudin administered alone or combined with unfractionated heparin. To assess the effect on thrombus growth, we determined the accretion of l25I-labeled fibrinogen onto autologous non-radioactive thrombi preformed in the jugular veins of rabbits. The rabbits received unfractionated heparin (80 anti-factor Xa U), LMWH (80 anti-factor Xa U) or r-Hirudin (0.3, 5.0 and 10.0 mg/kg) either separately or by combined infusion for a 3 h period.

R-Hirudin reduced the thrombus growth in a dose dependent fashion. The combined administration of 80 anti-Xa U LMWH and r-Hirudin at a dose of 0.3 mg/kg resulted in a stronger antithrombotic effect as compared to the combined infusion of unfractionated heparin and r-Hirudin (thrombus growth: 14.3% ± 6.0 vs 28.9% ± 6.5; p = 0.001). This difference in additive antithrombotic effect of 80 anti-Xa ULMWH versus unfractionated heparin on r-Hirudin was also observed when LMWH was combined with 5.0 mg/kg and 10.0 mg/kg r-Hirudin versus unfractionated heparin combined with r-Hirudin (thrombus growth: 16.4% ± 1.6 vs 29.1% ± 3.9; p = 0.01 and 10.1% ± 1.8 vs 20.4% ± 4.5; p = 0.001, respectively).

In conclusion, this study showed an additive antithrombotic effect of LMWH on the thrombus growth reducing effect of r-Hirudin. This may potentially be of clinical interest, i. e. much lower doses of r-Hirudin may be used to achieve a similar effective anticoagulant effect when combined with LMWH.
Antithrombotic Effects of Recombinant Human Soluble Thrombomodulin in a Rat Model of Vascular Shunt Thrombosis
Authors: Ono Mayumi , Nawa Katsuhiko , Marumoto Yasumasa
Published: July 2018

Thrombomodulin on endothelial cells is a cofactor for thrombin-catalyzed activation of protein C. We have investigated the anticoagulant function of recombinant human soluble thombomodulin (rsTM) in a rat model of arterio-venous (AV)-shunt thrombosis. A bolus injection of rsTM 30 s before the induction of AV-shunt thrombosis inhibited the thrombus formation in a dose-dependent manner. The dose of anticoagulant that inhibited thrombus formation by 50% was 0.4 mg/kg rsTMα, 0.15 mg/kg rsTMβ, and 13 U/kg heparin. Recently, we characterized three monoclonal antibodies (moAbs) against human TM whose epitopes are located in the TM epidermal growth factor-like domain (Nawa et al., 1994). moAb 2A2 inhibited thrombin binding to rsTM, and abolished both TM functions as a cofactor in thrombin-catalyzed activation of protein C and as an anticoagulant by modifying thrombin-induced fibrinogen clotting and platelet aggregation. moAb 1F2 preserved the latter activities as an anticoagulant, but inhibited cofactor activity. moAb 10A3 had no inhibitory effect on either activity. Analysis of the in vivo anticoagulant mechanism of rsTM was facilitated by the availability of these moAbs. After incubation at rsTM/moAb molar ratios of 1:1.25, the effect of the mixtures were examined in the AV-shunt thrombosis model. An injection of 0.8 mg/kg rsTMα or 0.4 mg/kg rsTMβ resulted in a significant reduction on thrombus formation, as expected. moAb 10A3 had no effect on rsTM activity. However, co-injection of rsTM with moAb 1F2 resulted in a significant decrease of the inhibitory activity on thrombus formation. moAb 2A2 essentially abolished the inhibitory effect of rsTM. These moAb effects were observed for both rsTMα and β. These results suggest that the protein C activation accelerated by the injection of rsTM plays an important role for inhibiting thrombus formation in the AV-shunt thrombosis model.
Polymorphonuclear Leukocyte-Platelet Interaction: Role of P-Selectin in Thromboxane B2 and Leukotriene C4 Cooperative Synthesis
Authors: Maugeri Norma , Evangelista Virgilio , Celardo Antonio , Dell’Elba Giuseppe , Martelli Nicola , Piccardoni Paola , de Gaetano Glovanni , Cerletti Chiara
Published: July 2018

In PMN/platelet suspensions stimulated by fMLP giant mixed aggregates are formed and TxB2 and LTC4 are synthesized as the result of the cooperation in the arachidonic acid (AA) metabolism during cell/cell contact. PMN-derived cathepsin G induced the expression of P-selectin on platelet surface. GE12, an antibody against P-selectin, significantly reduced mixed cell aggregates. GE12 did not affect platelet aggregation induced by PMN-derived supernatants, indicating that the inhibitory effect of GE12 on mixed cell aggregation depends on inhibition of PMN/platelet adhesion. GE12 significantly reduced TxB2 and LTC4 production in PMN/platelet mixed cell suspensions stimulated by fMLP. As previously reported, synthesis of 3H-TxB2 in 3H-AA-labeled PMN/unlabeled platelets indicates that platelets utilize 3H-AA from PMN. 3H-LTC4 production in unlabeled PMN/3H-AA-labeled platelets indicates that bidirectional routes are utilized in this system for LTC4 synthesis. GE12 significantly reduced 3H-TxB2 and 3H-LTC4 synthesis. These results show that cathepsin G released by activated PMN induces the expression of P-selectin on platelet membrane: this adhesive glycoprotein modulates cell-cell contact and transcellular metabolism of AA.
Participation of Soluble Fibrin Monomer Complexes and Platelet Factor 4 in the Generalized Shwartzman Reaction
Authors: Lipiński B , Worowski K , Jeljaszewicz J , Niewiarowski S , Rejniak L
Published: July 2018

The generalized Shwartzman reaction was produced in rabbits by the typical way of 2 consecutive injections of Salmonella typhi endotoxin. Generalized Shwartzman reaction was also induced by “preparation” of the rabbits with epsilon-aminocaproic acid or mercuric chloride intoxication, followed by a single injection of the endotoxin. Significant impairment of blood fibrinolytic activity resulting from inhibition by endotoxin of a release of the kidney plasminogen activator, was demonstrated in the classical generalized Shwartzman reaction. Inhibition of fibrinolysis led to the accumulation of soluble fibrin monomer complexes in the circulation, detectable in plasma by protamine sulfate precipitation. It is postulated that hypercoagulability, regularly occurring in the generalized Shwartzman phenomen, is due to fibrinolysis inhibition. Endotoxin causes release of platelet factor 4 from rabbit blood platelets both in vitro and in vivo. This factor is thought to be responsible for nonenzymatic intravascular precipitation of fibrin from circulating soluble fibrin monomer complexes. Bilateral cortical necrosis in kidneys is due by fibrin deposition resulting from the disturbance in the equillibrium between blood clotting and fibrinolytic systems and the interaction of accumulated soluble fibrin monomer complexes with platelet factor 4.
A Sensitive and Facile Assay for the Measurement of Activated Protein C Activity Levels in Vivo
Authors: Orthner Carolyn L , Kolen Billy , Drohan William N
Published: July 2018

Activated protein C (APC) is a serine protease which plays an important role as a naturally occurring antithrombotic enzyme. APC, which is formed by thrombin-catalyzed limited proteolysis of the zymogen protein C, functions as an anticoagulant by proteolytic inactivation of the coagulation cofactors VIIIa and Va. APC is inhibited by several members of the serpin family as well a by α2-macroglobulin. APC is being developed as a therapeutic for the prevention and treatment of thrombosis. We have developed an assay to quantify circulating levels of enzymatically active APC during its administration to patients, in healthy individuals, and in various disease states. This assay utilizes an EDTA-dependent anti-protein C monoclonal antibody (Mab) 7D7B10 to capture both APC and protein C from plasma, prepared from blood collected in an anticoagulant supplemented with the reversible inhibitor p-aminobenzamidine. Mab 7D7B10-derivatized agarose beads are added to the wells of a 96-well filtration plate, equilibrated with Tris-buffered saline, and incubated for 10 min with 200 μl of plasma. After washing, APC and protein C are eluted from the immunosorbent beads with a calcium-containing buffer into the wells of a 96-well microtiter plate containing antithrombin III (ATIII) and heparin. The amidolytic activity of APC is then measured on a kinetic plate reader following the addition of L-pyroglutamyl-L-prolyl-L-arginine-p-nitroanilide (S-2366) substrate.

The rate of substrate hydrolysis was proportional to APC concentration over a 200-fold concentration range (5.0 to 1,000 ng/ml) when measured continuously over a 15 to 30 min time period. The coefficient of variation was 5.9% at 35 ng/ml and 8.8% at 350 ng/ml APC. The sensitivity of the assay could be increased by measuring the amount of color produced after longer incubation times in the endpoint mode. The measured APC activity levels were little affected by varying protein C or prothrombin over the extremes of 0 to 150% of normal plasma concentrations. By constructing the standard curve in protein C-deficient plasma, the concentration of APC activity in normal pooled plasma was determined to be 2.8 ng/ml (45 pM), which represents 0.08% of the protein C concentration. The assay was approximately 50-fold more sensitive than the identical assay, but using Mab-coated microtiter wells rather than immunosorbent beads as the capture step.
Properties of Chimeric (Tissue-Type/Urokinase-Type) Plasminogen Activators Obtained by Fusion at the Plasmin Cleavage Site
Authors: Colucci M , Cavallo L G , Agnelli G , Mele A , Bürgi R , Heim J , Semeraro N
Published: July 2018

Two hybrid plasminogen activators (K2tu-PA and FK2tu-PA), linking the kringle 2 domain or the finger plus the kringle 2 domains of tissue-type plasminogen activator (t-PA) to the catalytic domain of single-chain urokinase-type plasminogen activator (scu-PA) were studied. At variance with similar constructs previously reported, they were obtained by fusion of the t-PA and scu-PA derived portions at their plasmin cleavage site (between Arg275 of t-PA and Ile159 of scu-PA), thus eliminating from scu-PA the two peptide bonds (Glu143-Leu144 and Arg156-Phe157) that lead to low molecular weight scu-PA and to thrombin-inactivated tcu-PA. The specific activities of K2tu-PA and FK2tu-PA, as measured by fibrin plate were 2.5 × 106 and 1.0 × 106 t-PA equivalent units/mg, respectively. Activation of plasminogen by hybrid PAs was stimulated by both CNBr-digested fibrinogen (40- and 80-fold) and Des-A-fibrin monomers (6- and 12-fold). The relatively weak stimulation of chimeric PAs by minimally degraded fibrin monomers was consistent with their reduced fibrin binding capacity. Like scu-PA, the chimeric PAs, in the single-chain form, were insensitive to inhibition, as they retained full activity after prolonged incubation in plasma and did not interact with SDS-reactivated recombinant PAI-1. The concentration producing 50% lysis of blood clots in 3 h was 0.5 μg/ml for K2tu-PA and 1 μg/ml for FK2tu-PA, as compared to 0.5 μg/ml and >2 μg/ml for t-PA and scu-PA, respectively. Plasminogen and α2-antiplasmin consumption induced by the hybrid PAs in clot-free plasma was comparable to (K2tu-PA) or lower than (FK2tu-PA) that induced by either t-PA or scu-PA. When exposed to plasmin, the hybrids were completely converted into two-chain molecules with full enzymatic activity. At variance with u-PA, however, the two-chain recombinant activators still required fibrin for full expression of activity. These data indicate that the products of such “artificial” fusion behave like true chimeras without loss of biological activity. The insensitivity to thrombin inactivation and to the proteolytic cleavage leading to low molecular weight scu-PA might confer enhanced stability to the molecules, especially at thrombus level. Moreover, if the thrombolytic activity observed in vitro is maintained in vivo, the prolonged half life of these hybrids should result in higher plasma levels of activator and thus in more extensive and rapid lysis.
Extent of Differentiated Gene Expression in the Human Endothelium-Derived EA.hy926 Cell Line
Authors: Rieber Alison J , Marr Henry S , Comer Mary B , Edgell Cora-Jean S
Published: July 2018

Vascular endothelial cells perform many differentiated functions in processes such as angiogenesis, hemostasis, and inflammation. The number of recognized differentiated functions has increased rapidly in recent years, but there may be many more still unrecognized. The purpose of this study is to estimate the fraction of differentially expressed mRNA in a continuous human endothelium-derived cell line, EA.hy926. Random cDNA clones representing mRNAs from this cell line were labeled and used to probe blots of RNA from EA.hy926 cells and from cells of a relatively undifferentiated line. Of 49 random cDNAs, 5 cDNAs or 10% were found to represent mRNAs that are differentially expressed in EA.hy926 and in early passage umbilical vein endothelial cells. Since more than 104 different genes are thought to be expressed in the typical mammalian cell, our data indicate that about 103 gene products contribute to the differentiated properties of endothelial cells.
Transmembrane Calcium Influx Associated with von Willebrand Factor Binding to GP Ib in the Initiation of Shear-Induced Platelet Aggregation
Authors: Ikeda Yasuo , Handa Makoto , Kamata Tetsuji , Kawano Koichi , Kawai Yohko , Watanabe Kiyoaki , Kawakami Keiko , Sakai Kiyotaka , Fukuyama Mayumi , Itagaki Ichiro , Yoshioka Akira , Ruggeri Zaverio M
Published: July 2018

We found that the binding of multimeric vWF to GP Ib under a shear force of 108 dynes/cm2 resulted in the transmembrane flux of Ca2+ ions with a two-to three-fold increase in their intracellular concentration ([Ca2+]i). The blockage of this event, obtained by inhibiting the vWF-GP Ib interaction, suppressed aggregation. In contrast, the blockage of vWF binding to GP IIb-IIIa, as well as the prevention of activation caused by increased intracellular cAMP levels, inhibited aggregation but had no significant effect on [Ca2+]i increase. A monomeric recombinant fragment of vWF containing the GP Ib-binding domain of the molecule (residues 445-733) prevented all effects mediated by multimeric vWF but, by itself, failed to support the increase in [Ca2+]i and aggregation. These results suggest that the binding of multimeric vWF to GP Ib initiates platelets aggregation induced by high shear stress by mediating a transmembrane flux of Ca2+ ions, perhaps through a receptor-dependent calcium channel. The increase in [Ca2+]i may act as an intracellular message and cause the activation of GP IIb-IIIa; the latter receptor then binds vWF and mediates irreversible aggregation.
Comparison Of Progressive Antithrombin Activity And The Concentration Of Three Thrombin Inhibitors In Nephrotic Syndrome
Authors: Boneu B , Bouissou F , Sié P , Caranobe C , Abbal M , Barthe P
Published: July 2018

A study was planed in 28 children affected with a nephrotic syndrome (group 1) in order to compare the total plasmatic progressive anti thrombin activity (Howie method) to the concentrations of three thrombin inhibitors, assayed by immunological methods : antithrombin III (AT III), α2 macroglobulin (α2 M), and al antitrypsin (α1 AT). The results were compared to those obtained in 21 normal children of the same age (group 2) and in 10 normal adults (age range : 25 - 50 yrs). The calibration curves were made with a pool of plasma from normal blood donors. The results (mean ± SD) and the comparison between groups 1 - 3 to group 2 are summarized.

A subgroup of 15 affected children which a low AT III level (less than 80%) was isolated (mean AT III = 51% ± 18) ; the mean of the total progressive anti thrombin activity was 124% ± 16. A significant negative relationship was found between AT III and α2 M level in the group 1 (r = -0.71, P <0.01).

The high plasmatic level of α2 M (1) accounts for the increased progressive anti thrombin activity in all the affected children in spite of very low levels of AT III ; (2) could explain the absence of thrombotic events in this serie ; (3) suggests that the benefit of heparin therapy might be doubtfull since it has been recently reported that heparin inhibit the binding of α2 M to thrombin.
The Effect Of Tranexamic Acid On Experimental Gastric Haemorrhage
Authors: Stenberg B , Alpsten M , Kjellström T , Risberg B
Published: July 2018

The etiology of gastric haemorrhage is manifold. Defects in the haemostatic balance can provoke or sustain bleeding. The role of the fibrinolytic system has been debated. Some clinical studies indicate the value of antifibrinolytic treatment.

It was the purpose of the present investigation to study the effectiveness of antifibrinolytic treatment in reducing gastic haemorrhage from experimentally induced ulcerations in rats.

Methods. Gastric ulcerations were induced in 47 rats by pyloric ligation and intragastric instillation of 1.0 N HCI. Red blood cells were labelled with 51cr. The rats were divided in two groups: one group received tranexamic acid 60 mg per 100 g b.w. and the other group received corresponding amount normal saline. The rats were followed for 6 hours after ligation at which time the stomachs were removed and examined for the volume and radioactivity of the gastric content.

Results. Six hours after pyloric ligation all rats had ulcers in the glandular part of the stomach. The volume of the gastric content in the control group was 15.1 ± 1.0 and in the tranexamic acid group 8.9 ± 2.2 ml (M±SE, p<0.01). The total amount of haemorrhage in the control group was 0.30 ± 0.02 and in the tranexamic acid group 0.21 ± 0.02 ml(M±SE, p<0.005)

Conclusions. Our earlier studies demonstrated increased mucosal fibrinolytic activity after induced gastric ulcerations. Reduction of the increased muosal fibrinolysis by tranexamic acid in the present study significantly reduced the gastric haemorrhage.
Acyl-Enzymes As Fibrinolytic Agents
Authors: Smith R A G
Published: July 2018

Plasminogen activators or plasmins specifically and reversibly acylated at the active centre have been used as delivery systems for fibrinolytic agents in vivo. Potential advantages of this approach, including enhanced efficacy, reduced toxicity and better control of lysis are discussed. General chemical methods for specific acylation of these enzymes are given and structure-activity relationships for deacylation outlined. Evidence for the activity of acyl-plasmins in vitro and the evasion of plasma antiplasmins by these derivatives is presented. Kinetic schemes for fibrinolysis by acyl-enzymes in vivo and the use of these models for prediction of optimal deacylation rate constants for each class of agent are briefly discussed.
Endotoxin And Blood Coagulation In Patients With Traumatic- Haemorrhagic And Bacteriotoxic Shock
Authors: Stemberger A , Straßer F , Blüimel G , Hundel shausen B v , Jelen S , Schmid O , Tempel G
Published: July 2018

Blood coagulation and fibrinolysis was carefully monitored in patients suffering from traumatic-haemorrhagic shock. Parameters like antithrombin III (AT III),factor X (IIa), plasminogen,fibrin degradation products, antiplasmin and fibronectin were measured. It could be demonstrated that a severe haemorrhagic shock correlated with an activated blood coagulation and stabilisation of circulation was followed by normalisation of blood coagulation.

However in patients developping septic complications new disorders in blood coagulation were observed. The appearance of endotoxins was measured by a recently developped limulus amoebocyte lysate (LAL). Best results were obtained by diluting heat treated heparinized plasma samples followed by an incubation step with the X a substrate S-2222. Detection of less than 0.2 ng endotoxin/ml plasma could be achieved. The available data of 30 patients with traumatic-haemorrhagic and bacteriotoxic shock showed that the appearance of endotoxin mostly correlated with a decrease of AT III and fibronectin.

In conclusion, AT III, fibronectin and endotoxin may serve as sensitive markers in the early diagnosis of sepsis.
Deep Venous Thrombosis Of The Upper Extremity With Special Emphasis On Studies Of Coagulation And Fibrinolysis
Authors: Sundqvist S B , Hedner U , Bergentz S E , Kullenberg K
Published: July 2018

Deep venous thrombosis (DVT) in the upper extremity is rare as compared to DVT in the leg. It has been claimed to be caused often by trauma to the axillary vein or unaccustomed heavy work (“effort”) with the arms. Our series of 53 patients shows the same peak incidence with regard to age (mean age 32.4+11.7) as earlier reported. However, a preceding trauma or “effort” was only found in 12 % in this particular series of patients. Other predisposing factors such as cancer (2/53), thoracic outlet syndrome (3/53) etc were rare. The coagulation studies included the following analyses: VIII:C, VIIIR:Ag, AT III and inhibitors of the plasminogen activators (PA inhibitor). The vessel wall fibrinolysis was studied in two different ways: 1) the capacity to release fibrinolytic activators from the vessel wall (venous occlusion test according to Robertson et al (1972), and 2) the fibrinolytic activity within the vessel wall (histochemical technique according to Pandolfi 1972). An impaired vessel wall fibrinolysis was found in 49 % of our patients which is a slightly lower figure than the 70 % incidence of this abnormality found in patients with spontaneous DVT in the lower extremity. The higher incidence of females as compared to earlier reports could not be explained by the use of contraceptive pills since the frequency of women on the pill seemed to be about the same as in the Swedish population as a whole.

All patients had normal values of factor VIII, AT III and PA inhibitors.

It is concluded that an impaired vessel wall fibrinolysis may be an important contributing factor also for DVT in the arm. Fibrinolytic studies may therefore be important in evaluating these patients.
Consumption of Hageman Factor Activity in the Generalized Shwartzman Reaction Induced by Liquoid
Authors: Müller-Berghaus G , Lasch H. G
Published: July 2018

The role of Hageman factor in triggering intravascular coagulation has been studied in rabbits injected intravenously with Liquoid. Besides changes of coagulation parameters characteristic of consumption coagulopathy (e.g. decrease in platelet counts, fibrinogen levels, factor V activity), a pronounced drop in Hageman factor activity was observed after injection of Liquoid. Likewise, the partial thromboplastin time became prolonged.

The activation of Hageman factor in vivo could be prevented by intravenous infusion of lysozyme. Twenty min after starting the lysozyme infusion, the partial thromboplastin time became prolonged from a mean of 29 sec to 108 sec. Animals infused with lysozyme and injected with a lethal dose of Liquoid did not develop a consumption coagulopathy. In the same manner, none of 10 animals treated with lysozyme developed the generalized Shwartzman reaction, whereas in the control group 19 out of 20 animals showed fibrin thrombi in the glomerular capillaries.

From the present study it may be concluded that the intravascular coagulation process after intravenous injection of Liquoid is triggered by Hageman factor activation.
Antihemophilic Factor: Its Presence in Fibrinogen, Assay Problems and the Stability of Lyophilized AHF-Fibrinogen Preparations
Authors: Baumgarten Werner , Sanders Benjamin E. , Belkin Benita D , Pagenkemper Frank E , Albers William G , Ciminera Joseph L
Published: July 2018

The thromboplastin generation test of Biggs et al. and of Pitney, and adopted by Surgenor for the assay of antihemophilic factor activity in lyophilized preparations of human fibrinogen, has been modified to yield a selfcontained statistically valid assay. This procedure was designed to serve primarily as a control procedure. The AHF activity of production lots of human fibrinogen was assayed, and the stability of AHF under different conditions of storage was determined.

The procedure described in this paper is a satisfactory control procedure for AHF potency testing. In the absence of a generally recognized unit of AHF potency, it would seem most helpful to the clinician to have the potency related to the average activity in fresh normal human plasma.
Elinin and Blood Coagulation
Authors: Vulpis Nicoletta , Vulpis G , Santoro C
Published: July 2018

Investigations were performed on the effects of elinin on blood coagulation. It was found that elinin exerts significant anticoagulant activity. This was demonstrated by an one-stage re calcification test, prothrombin consumption, thromboplastin and thrombin generation. The conclusion was that the anticoagulant activity of EL is probably due to the high molecular weight of its molecule.
Self-Coagulogram
Authors: Berkarda Bülent , Akokan Gönül , Derman Ugur
Published: July 2018

A curve named “self-coagulogram” and obtained by means of the “self thromboplastin-prothrombin time” is described. The beginning of the curve reflects clot formation dynamics, while the tail reflects the fibrinolytic activity. The self-coagulogram helps the detection of hemorrhagic syndromes, the evaluation of anticoagulant therapy and fibrinolytic activity, natural or induced. It is a very simple and practical method.
Subwavelength imaging designed with meander-line anisotropic epsilon-near-zero (AENZ) metamaterial structures
Authors: Xu Xiaofei , Wang Yefang , Wei Juzheng
Published: July 2018

Subwavelength imaging is designed and demonstrated utilizing practical meander-line metamaterial structures in this work. By carefully designing the composite structure, desirable anisotropic epsilon-near-zero (AENZ) index is obtained. To verify the imaging performance, a 3D model is constructed which is composed of period meander-line elements in numerical validation. Imaging in super resolution is observed. We remark that in the model, both of natural material loss and finite element size effect are considered mimicking practical scenarios. The demonstration results are convincing and helpful to provide practical insights for future applications of subwavelength imaging in microwave frequency range.
Short-pulse-induced solute migration in the C49H43ClO6 + 1,2 dichloroethane solution
Authors: Kuo Yu-Ting , Liu Po-Wei , Huang Po-Yuan , Li Yi-Ci , Wei Tai-Huei
Published: July 2018

Using the Z-scan technique with 532 nm 19 ps laser pulses separated by two time intervals τp-p’s (0.1 s and 1.0 s) sandwiching the mass diffusion time constant of the C49H43ClO6 + 1,2 dichloroethane solution, we investigate short-pulse-induced solute migration in the sample by measuring its transmittance change with τp-p variation. Preparing the sample at two concentrations, we find that τp-p reduction, from 1.0 s to 0.1 s, increases its transmittance when input pulse energy ε1 exceeds a threshold εT, which is lower for the dilute solution than the concentrated one. At two ε1’s above εT for the dilute solution, τp-p-reduction-induced transmittance increase in the dilute solution, as compared to that in the concentrated solution, is more at the lower ε1 and less at the higher ε1. This differs from continuous-wave-driven thermal diffusion which always causes a larger transmittance increase in the concentrated solution by inducing a larger temperature gradient. From this study, we predict that solute migration induced by short pulses at 1064 nm is one of the undesired heating effects occurring when this solution is used to simultaneously Q-switch and mode-lock Nd:YAG lasers.
Solitons, the Korteweg-de Vries equation with step boundary values, and pseudo-embedded eigenvalues
Authors: Ablowitz M. J. , Luo X.-D. , Cole J. T.
Published: July 2018

The Korteweg-deVries (KdV) equation with step boundary conditions is considered, with an emphasis on soliton dynamics. When one or more initial solitons are of sufficient size, they can propagate through the step; in this case, the phase shift is calculated via the inverse scattering transform. On the other hand, when the amplitude is too small, they become trapped. In the trapped case, the transmission coefficient of the associated linear Schrödinger equation can become large at a point exponentially close to the continuous spectrum. This point is referred to as a pseudo-embedded eigenvalue. Employing the inverse problem, it is shown that the continuous spectrum associated with a branch cut in the neighborhood of the pseudo-embedded eigenvalue plays the role of discrete spectra, which in turn leads to a trapped soliton in the KdV equation.
Modal analysis of the full poloidal structure of the plasma response to n = 2 magnetic perturbations
Authors: Munaretto S. , Strait E. J. , Haskey S. R. , Logan N. C. , Paz-Soldan C. , Weisberg D. B.
Published: July 2018

Previous DIII-D research has identified the presence of a multimodal plasma response to perturbations with toroidal periodicity equal to 2, with kink-like phenomenology of the plasma response in the low field side mid-plane and a resonant-like behavior in the high field side midplane. In this paper, we extend that initial midplane observation with the first detailed analysis of the poloidal structure of the plasma response as a function of the poloidal spectrum of the applied n = 2 perturbation and compare it to predictions made with the linear magnetohydrodynamics code MARS-F, confirming an overall good agreement. Singular value decomposition analysis of both the experimental data and the modeling identifies two distinct poloidal mode structures, one peaking at the low field side midplane and one peaking at θ ± 50°, each with a well-defined dependence on the poloidal spectrum of the applied perturbation. A study of the effect that βN has on the two modes confirms the kink-like phenomenology of the plasma response that dominates the low field side mid-plane, shows that the behavior previously associated with the high field side is observable at all poloidal angles, and highlights that the mode dominant at low βN becomes the secondary one at high βN. Detailed analysis of the high field side response is presented as well, suggesting the presence of a third mode linked to the presence of non-linear effects corresponding to particular poloidal spectra of the applied perturbation.
Spatially resolved observation of water transport across nanomembranes using bright-field nanoscopy
Authors: Suran Swathi , Balasubramanian Krishna , Raghavan Srinivasan , Varma Manoj M.
Published: July 2018

Gaining a detailed understanding of water transport behavior through ultra-thin membranes including atomically thin graphene layers is increasingly becoming necessary due to their potential applications in water desalination and ion separation. It is important to correlate the nanoscopic architecture of the membrane with the macroscopic properties such as the average water transport rate and the ion selective transport rates. Such correlations are only possible when spatially resolved (in the lateral direction) information of mass transport across the membrane is available. Then, one will be able to identify the relative role of grain boundaries, defects, and other topographical structures of interest in determining the macroscopic parameters which will aid in optimizing the fabrication processes of such membranes. Current techniques do not provide spatially resolved information and only provide macroscopic parameters such as the bulk water transport rate. We describe a technique, referred to here as Bright-Field Nanoscopy (BFN), which provides a spatially resolved measurement of water transport across nanomembranes. Using this technique, we demonstrate how grain engineering of atomically thin chemical vapor deposited graphene membranes can tune the bulk water transport rate across the membranes by orders of magnitude. BFN exploits the strong thickness dependent color response of an optical stack consisting of a thin (∼25 nm) germanium film deposited over a gold substrate and only requires a regular bright-field microscope for data acquisition. To show the generality of this technique, we demonstrate the strong influence of the terminal layer on the bulk water transport rates in thin (∼20 nm) layer-by-layer deposited polyelectrolyte multilayer films by exploiting the spatially resolved nature of the acquired data. We also show that by controlling the ambient conditions, the effect of the terminal layer can be completely suppressed.
Enhanced photoresponse of graphene oxide functionalised SnSe films
Authors: Yao Hao , Luo Siwei , Duesberg Georg S. , Qi Xiang , Lu Donglin , Yue Chao , Zhong Jianxin
Published: July 2018

The successful synthesis of large-area SnSe films on SiO2/Si substrate through vapor transport is reported. Based on this we fabricated photodetectors that exhibited a fast response from ultraviolet (UV) to near infrared (NIR) wavelengths. By decorating the SnSe film with graphene oxide quantum dots (GO QDs) the photocurrent and photoresponse time were enhanced significantly over the whole spectrum. Our results indicate that GO functionalised SnSe is a promising material for broadband photodetection.
Conceptual design of extended magnetic probe set to improve 3D field detection in NSTX-U
Authors: Munaretto S. , Strait E. J. , Lanctot M. J. , Wang Z. R.
Published: July 2018

Adding toroidal arrays of magnetic probes at the top and bottom of NSTX-U would improve both the detection of the multimodal plasma response to applied magnetic perturbations and the identification of the poloidal structure of unstable plasma modes, as well as contribute to the validation of MHD models, improve the understanding of the plasma response to external fields, and improve the error field correction. In this paper, the linear MHD code MARS-F/K has been used to identify poloidal locations that would improve the capability to measure stationary or near-stationary 3D fields that may result from the plasma response to external sources of non-axisymmetric fields. The study highlighted 6 poloidal positions where new arrays of both poloidal and radial magnetic field sensors would improve the poloidal resolution. The proposed set of new arrays combined with the present ones is shown to be capable of measuring the poloidal structure of perturbations with n ≤ 6 and of detecting the multimodal plasma response. Assessment of the trade-off in the poloidal length of the probes leads to an ideal length between 10 cm and 30 cm. A method to configure the probes of a toroidal array based on the singular value decomposition condition number is proposed, and an ideal solution and a low-cost one are presented.
X-ray spectroscopy comparison methods for diagnostics of high-temperature molybdenum plasmas
Authors: Shevelko A. P. , Yakushev O. F. , Vainshtein L. A. , Andreev S. N. , Tolstikhina Inga Yu.
Published: July 2018

A comparison method of high-temperature plasma diagnostics, developed by Shevelko [Quantum Electron. 41, 726 (2011)] and Shevelko et al. [Plasma Phys. Rep. 34, 944 (2008)], is modified and applied for Mo laser-produced plasma analyses. This method consists in determining the electron temperature Te of the studied plasmas by comparing the spectra of the investigated radiation source with the spectra of well-diagnosed laser-produced plasmas recorded at different Te. The modified comparison method includes the theoretical modeling of X-ray spectra of laser-produced plasmas of different elements. The most complete correspondence between the structure of the theoretical spectrum and the experimental one is achieved by changing the single parameter in theoretical calculations—the electron temperature Te. Such a method made it possible to describe in detail the structure of the X-ray spectra of multiply charged Mo ions, improve the accuracy of measurements, and justify the methods used. In particular, for Mo laser plasma (3-2 transitions in Mo31+-Mo34+ ions), the electron temperatures determined experimentally by the comparison method (Te = 685 ± 55 eV) and calculated theoretically (Te = 650 eV) are in a very good agreement.
Enhancement of resistive switching ratio induced by competing interfacial oxygen diffusion in tantalum oxide based memories with metal nitride electrode
Authors: Hu Lei , Zhu Shengju , Wei Qi , Chen Yan , Yin Jiang , Xia Yidong , Liu Zhiguo
Published: July 2018

Oxide-based binary resistive switching memories using metal nitride as one of the electrodes usually have a limited ratio of the resistances of the high- and low-resistance states. Here, we propose a competing mechanism to enhance the switching ratio by modifying the high-resistance state with extra inherent interfacial oxygen diffusion against what happens at the oxide/nitride interface. This is implemented in Pt/ZrO2/Ta2O5/TaN bilayer structures, where a resistance ratio above 104, about one to two orders of magnitude greater than that in Pt/Ta2O5/TaN monolayer structures, is achieved. This competing mechanism is further corroborated by the failed enhancement in the switching ratio when using an altered stacking arrangement of the two oxide layers.
Spatial dispersion of the high-frequency conductivity of two-dimensional electron gas subjected to a high electric field: Collisionless case
Authors: Korotyeyev V. V. , Kochelap V. A. , Danylyuk S. , Varani L.
Published: July 2018

We present the analysis of high-frequency (dynamic) conductivity with the spatial dispersion, σ(ω, q), of two-dimensional electron gas (2DEG) subjected to a high electric field. We found that at finite wavevector, q, and at high fields, the high-frequency conductivity shows following peculiarities: strong non-reciprocal dispersion, oscillatory behavior, a set of frequency regions with negative σ′, and non-exponential decay of σ′ and σ″ with frequency (opposite to the Landau damping mechanism). We illustrate the general results by calculations of spectral characteristics of particular plasmonic heterostructures on the basis of III-V semiconductor compounds. We conclude that the detailed analysis of the spatial dispersion of the dynamic conductivity of 2DEG subjected to high electric fields is critically important for different THz applications.
Alternating streamer propagation in mineral oil under bipolar oscillating impulse voltage
Authors: Ni Heli , Zhang Qiaogen , Wu Zhicheng , Fan Xing , Liu Xuandong
Published: July 2018

This study aimed to clarify the basic process of streamer propagation in mineral oil at bipolar oscillating impulse voltage. Shadow images and light signals of streamers showed that under bipolar oscillating impulse, positive and negative streamers propagated in an alternating manner: after polarity reversal, new streamers with opposite polarity were initiated and propagated first through the gaseous channels left behind by former streamers and then toward the ground electrode. The velocity of positive streamers was found nearly an order of magnitude higher than that of negative ones; thus, positive streamers are primarily responsible for the insulation failure of mineral oil. Negative streamers played the role of maintaining gaseous channels and facilitating positive streamers initiation due to their strong heat effect. High oscillation frequency and large damping factor decreased the durations and amplitudes of positive peaks, which restrained positive streamer propagation and further resulted in the increase in the breakdown voltage. Experiments on dielectric behavior of mineral oil were conducted to verify above inferences.
Communication: Accurate description of interaction energies and three-body effects in weakly bound molecular complexes by PBE-QIDH models
Authors: Pérez-Jiménez A. J. , Brémond E. , Adamo C. , Sancho-García J. C.
Published: July 2018

We apply a recently developed parameter-free double-hybrid density functional belonging to the quadratic-integrand double-hybrid model to calculate association energies (ΔE) and three-body effects (Δ3E) arising from intermolecular interactions in weakly bound supramolecular complexes (i.e., the dataset 3B-69). The model behaves very accurately for trimer association energies and is found to outperform widely used density functional approximations while approaching the accuracy of more costly ab initio methods for three-body effects. The results are further improved when we add some specific corrections for the remaining dispersion interactions, D3(BJ) or VV10 for two-body effects and Axilrod-Teller-Muto for three-body effects, leading to marginal deviations (less than 1 kcal/mol for ΔE and around 0.03–0.04 kcal/mol for Δ3E) with respect to benchmark results.
Microrheology of DNA hydrogels
Authors: Xing Zhongyang , Caciagli Alessio , Cao Tianyang , Stoev Iliya , Zupkauskas Mykolas , O’Neill Thomas , Wenzel Tobias , Lamboll Robin , Liu Dongsheng , Eiser Erika
Published: July 2018

Significance

While widely known as the molecule of life, DNA is also an amazing building block at the nanoscale, since it allows us to design and program the structure and dynamics of functional nanomaterials. We exploit the programmability of DNA to achieve control over the rheology of self-assembled hydrogels, which have elastic or viscous behavior (similar to that of slime) that is finely regulated by temperature. Using microrheology to investigate the mechanical properties of DNA hydrogels at the microlength scale, we map the viscoelastic response over a broad range of frequencies and temperatures. The deep understanding in the fundamental physics provides a way to design DNA-based materials with precise control over the structure stability and rigidity at molecular level.
Nonverbal predication in Kari’nja (Cariban, Suriname)
Authors: Sapién Racquel-María
Published: July 2018

This paper describes the forms and functions of nonverbal predication in Kari’nja (Cariban, Suriname). Previous descriptions of nonverbal predication in Kari’nja are limited to a single copular form, and make only passing mention of a subset of functions. Kari’nja employs the copula, as well as apposition (without a copula), and a verbal copula. Formally, each of the three nonverbal predicate structures differs in terms of person marking, negation, TAM, number, interrogative forms, and the types of complements it permits. In addition to structural characteristics, each construction differs in terms of which functional categories it encodes. This paper describes the formal properties and functional motivation for using each available construction in Kari’nja. It thereby provides a more complete analysis of the Kari’nja system specifically, examines the typological characteristics of nonverbal predication more generally, and contributes to our understanding of the ways in which systems can vary and change.
Generation of (2-Nitroethyl)benzene and related benzenoids from L-Phenylalanine; flower scents of the Japanese Loquat Eriobotrya japonica [Rosales: Rosaceae]
Authors: Kuwahara Yasumasa , Asano Yasuhisa
Published: July 2018

(2-Nitroethyl)benzene, methyl 4-methoxybenzoate and 4-methoxybenzaldehyde have been known as major scent components in flowers of the Japanese loquat Eriobotrya japonica [Rosales: rosaceae], together with 13 related benzenoids, including Z- and E-2-phenylacetaldoxime and benzyl alcohol. The scents air-trapped from a flowering panicle during 24 h incubation with d8-L-phenylalanine were composed of 15 deuterium labeled compounds {d6-styrene, d5-benzaldehyde, d7-2-phenylacetaldehyde, methyl d5-benzoate, d7 −2-phenylethanol, d7-2-phenylacetonitrile, d4-1,4-dimethoxybenzene, d7-Z-2-phenylacetaldoxime, d4-4-methoxybenzaldehyde, d7-E-2-phenylacetaldoxime, d4-4-methoxybenzyl alcohol, d7-(2-nitroethyl)benzene, methyl d4-4-methoxybenzoate, methyl d6-cinnamate and ethyl d4-4-methoxybenzoate}. On the other hand, hexane extracts of the flower petal incubate with a mixture of d5-Z- and d5-E-2-phenylacetaldoxime after 24 h indicated generation of six d5-labeld components {d5-benzaldehyde, d5-benzyl alcohol, d5-2-phenylacetaldehyde, methyl d5-benzoate, d5-2-phenylethanol, and d5-(2-nitroethyl)benzene}. By comparing those results, (2-nitroethyl)benzene was concluded as a product directly generated from a mixture of Z- and E-2-phenylacetaldoxime together with six minor benzenoids, while two major compounds (4-methoxybenzaldehyde and methyl 4-methoxybenzoate) together with three minors from L-phenylalanine, presumably via L-tyrosine. The other two minor components were derived from L-phenylalanine.
Symplectic models for unitary groups
Authors: Dijols Sarah , Prasad Dipendra
Published: July 2018

In analogy with the study of representations of

GL

2
n

⁡
(
F
)

\operatorname {GL}_{2n}(F)

distinguished by

Sp

2
n

⁡
(
F
)

\operatorname {Sp}_{2n}(F)

, where

F
F

is a local field, we study representations of

U

2
n

⁡
(
F
)

\operatorname {U}_{2n}(F)

distinguished by

Sp

2
n

⁡
(
F
)

\operatorname {Sp}_{2n}(F)

in this paper. (Only quasisplit unitary groups are considered in this paper since they are the only ones which contain

Sp

2
n

⁡
(
F
)

\operatorname {Sp}_{2n}(F)

.) We prove that there are no cuspidal representations of

U

2
n

⁡
(
F
)

\operatorname {U}_{2n}(F)

distinguished by

Sp

2
n

⁡
(
F
)

\operatorname {Sp}_{2n}(F)

for

F
F

a nonarchimedean local field. We also prove the corresponding global theorem that there are no cuspidal automorphic representations of

U

2
n

⁡
(

A

k

)

\operatorname {U}_{2n}(\mathbb {A}_k)

with nonzero period integral on

Sp

2
n

⁡
(
k
)
∖

Sp

2
n

⁡
(

A

k

)

\operatorname {Sp}_{2n}(k) \backslash \operatorname {Sp}_{2n}(\mathbb {A}_k)

for

k
k

any number field or a function field. We completely classify representations of quasisplit unitary groups in four variables over local and global fields with nontrivial symplectic periods using methods of theta correspondence. We propose a conjectural answer for the classification of all representations of a quasisplit unitary group distinguished by

Sp

2
n

⁡
(
F
)

\operatorname {Sp}_{2n}(F)

.
Electric field–induced migration and intercellular stress alignment in a collective epithelial monolayer
Authors: Cho Youngbin , Son Minjeong , Jeong Hyuntae , Shin Jennifer H.
Published: July 2018

During wound healing, cells migrate with electrotactic bias as a collective entity. Unlike the case of the electric field (EF)-induced single-cell migration, the sensitivity of electrotactic response of the monolayer depends primarily on the integrity of the cell–cell junctions. Although there exist biochemical clues on how cells sense the EF, a well-defined physical portrait to illustrate how collective cells respond to directional EF remains elusive. Here, we developed an EF stimulating system integrated with a hydrogel-based traction measurement platform to quantify the EF-induced changes in cellular tractions, from which the complete in-plane intercellular stress tensor can be calculated. We chose immortalized human keratinocytes, HaCaT, as our model cells to investigate the role of EF in epithelial migration during wound healing. Immediately after the onset of EF (0.5 V/cm), the HaCaT monolayer migrated toward anode with ordered directedness and enhanced speed as early as 15 min. Cellular traction and intercellular stresses were gradually aligned perpendicular to the direction of the EF until 50 min. The EF-­induced reorientation of physical stresses was then followed by the delayed cell-body reorientation in the direction perpendicular to the EF. Once the intercellular stresses were aligned, the reversal of the EF direction redirected the reversed migration of the cells without any apparent disruption of the intercellular stresses. The results suggest that the dislodging of the physical stress alignment along the adjacent cells should not be necessary for changing the direction of the monolayer migration.