bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of an In Vitro Model to Study the Permeability of Human Arterial Endothelial Cell Monolayers
Authors: Langeler Erna G , van Hinsbergh Victor W M
Published: June 2018

A model has been developed to study the transport of fluid and macromolecules through human arterial umbilical cord endothelial cell monolayers in vitro. Cells were cultured on fibronectin- coated polycarbonate filters and formed within a few days a tight monolayer, with an electrical resistance of 17 ± 4 Ohm · cm2. The cells were connected by close cell contacts with tight junctions. The passáge-rate of horse radish peroxidase (HRP) through these filters was 20-40 fold lower than through filters without an endothelial monolayer. The continuous presence of 10% human serum was needed to maintain the electrical resistance of the monolayer and its barrier function towards macromolecules. Chelation of extracellular calcium resulted in an increased permeability and a decreased electrical resistance of the monolayer. This process was reversible by re-addition of calcium ions to the cells. The permeation rate of dextrans of various molecular weights (9-480 kD) was inversely related to the molecular mass of the molecule. No difference was measured between the passage rate of dextran of 480 kD and dextran of 2,000 kD. Incubation of the endothelial cell monolayer with 2-deoxy-D-glucose resulted in a decreased permeability but it had no effect on electrical resistance. This suggests that the passage-process is energy- dependent.

Fluid permeation through the endothelial cell monolayer on filters was measured in a perfusion chamber under 20 mmHg hydrostatic pressure. It was decreased by the presence of serum proteins and responded reversibly on the chelation and readdition of extracellular calcium ions.
Increased Plasminogen Activator Inhibition Levels in Malignancy
Authors: de Jong Egbert , Knot Eduard A R , Piket Dick , Iburg Alfred H C , Rijken Dick C , Veenhof Kees H N , Dooijewaard Gerard , ten Cate Jan W
Published: June 2018

Plasminogen activator(PA) - tissue and urokinase type - and PA-inhibition in plasma were investigated in 52 consecutive cancer patients with a variety of tumors. At first patients were analyzed as one group. Secondly patients were subdivided into two groups, one with (n = 42) and one without (n = 10) metastasis. Our results show that tissue-type-PA antigen (t-PA-antigen) and PA-inhibition were both significantly increased irrespective of the presence or absence of tumor metastasis (p <0.001) compared to age matched healthy controls. In the group without metastasis a significantly decreased level of t-PA activity was found (p <0.001) but in the group with metastasis t-PA activity was normal. These data seem to reject the hypothesis that decreased plasma fibrinolytic activity is one of the prerequisites for tumor metastasis.
Hemorrhagic Thrombocytopathy with Platelet Thromboxane A2 Receptor Abnormality: Defective Signal Transduction with Normal Binding Activity
Authors: Ushikubi Fumitaka , Okuma Minoru , Kanaji Kenji , Sugiyama Tateo , Ogorochi Toshiya , Narumiya Shuh , Uchino Haruto
Published: June 2018

Subnormal platelet responses to thromboxane A2 (TXA2) were found in a patient with polycythemia vera, and the mechanism of this dysfunction was analyzed. The patient’s platelets showed defective aggregation and release reaction to arachidonic acid, enzymatically generated TXA2 and synthetic TXA2 mimetics (STA2, U-46619). In contrast, they showed normal responses to thrombin. When the platelet TXA2 receptor was examined with both a 125I-labelled derivative of a TXA2 receptor antagonist ([125I]-PTA-OH) and a 3H-labelled TXA2 agonist ([3H]U-46619), the equilibrium dissociation rate constants (Kd) and the maximal concentrations of binding sites (Bmax) of the patient’s platelets to both ligands were within normal ranges, suggesting that the binding capacity of their TXA2 receptor was normal. STA2 failed to induce normal elevation in the. cytoplasmic free calcium ion concentration, phosphatidic acid formation and 40 kD protein phosphorylation in the patient’s platelets, whereas these responses to thrombin were within normal ranges. 12-O-Tetradecanoyl-phorbol-13-acetate (TPA) also evoked normal response in the 40 kD protein phosphorylation in the patient’s platelets. These results suggested that the patient’s platelets had TXA2 receptor abnormalities which were characterized by defective transduction of the binding signal to postreceptor reactions after normal TXA2 binding.
Effect of the Polyamine-Spermine on Agonist-Induced Human Platelet Activation - Specific Inhibition of "Aggregation-Independent" Events Induced by Thrombin, but not by Collagen, Thromboxane Mimetic, Phorbol Ester or Calcium lonophore
Authors: Joseph Sunil , Krishnamurthi Sushila , Kakkar Vijay V
Published: June 2018

Spermine, a naturally occurring polyamine, has previously been described as an inhibitor of purified phospholipase C and protein kinase C in cell-free systems. The present study examines the effect of spermine on platelet aggregation, dense-granule secretion and thromboxane (Tx) B2 synthesis induced by a variety of agonists, which cause the activation of one or both enzymes to different extents. These studies revealed that, while spermine (10 mM) inhibited platelet aggregation in response to all the agonists examined, [14C]-5-hydroxytryptamine (5HT) release and TxB2 synthesis induced by thrombin (0.2 U/ml) and collagen (10-40 μg/ml) alone, were inhibited by spermine, the percentage inhibition being >90% for both responses with thrombin, 30% for 5HT release and 80% for TxB2 synthesis with collagen. The inhibition of collagen-induced [14C]-5HT secretion by spermine was due entirely to the inhibition of aggregation-dependent TxA2 synthesis as addition of a sub-threshold concentration of U46619, which induced no secretion on its own, totally restored collagen-induced [14C]-5HT secretion to the levels seen in the absence of spermine. Moreover, collagen-induced TxB2 formation in unstirred platelets, which occurred independently of aggregation was not significantly affected by spermine (10 mM). However, the inhibition of maximal thrombin-induced [14C]-5HT secretion and TxB2 synthesis, which are both aggregation-independent phenomena, could be attributed to the inhibition of thrombin-induced diacylglycerol formation and intracellular calcium mobilization, which were both inhibited by 80% in the presence of spermine. These results suggest that spermine may be a specific inhibitor of thrombin-induced platelet responses rather than a generally effective inhibitor of platelet phospholipase C and protein kinase C or the activation of these enzymes in response to agpnists other than thrombin, at least when added exogenously to intact platelets. This thrombin-specific inhibition may be due to an interference of the binding of thrombin to its platelet receptor and/or interference at a step following thrombin binding, which is involved in the subsequent coupling processes.
Studies on Human Platelets
Authors: Booyse F. M , Zschocke Dorothea , Hoveke T. P , Rafelson M. E
Published: June 2018

Human platelets have been separated into 4 more homogeneous populations (A, B, C, and D; D population of highest density) by isopycnic density gradient centrifugation. Newly formed platelets have been identified in band C. These newly formed platelets age in vivo and shift into band D containing mature and old platelets. Newly formed platelets are more active in their ability to incorporate labeled amino acids into protein than mature and/or older platelets. The maturation of newly formed platelets (shift from band C to band D) is concurrent with a gradual loss in their ability to synthesize protein, a increase in density and decrease in size. In addition, newly formed platelets have a lower content of thrombosthenin than do mature (old) platelets.
Experimental Arterial Thrombosis in Rats with Continuous Registration
Authors: Hladovec J
Published: June 2018

The author describes a method of experimental arterial thrombosis in rats suitable for testing drugs with suggested antithrombotic effects. The thrombosis was provoked by electric current in the carotid artery and continuously registered by a contact thermometer.
“Angiokinase” - Molecular Weights of Proteins Representing a Perivascular Plasminogen Activator
Authors: Auerswald W , Binder B , Doleschel W
Published: June 2018

By means of gel filtration (Sephadex G-150) of precipitates originating from human cadaver vessel perfusates the molecular weights of a perivascular plasminogen activator “angiokinase” were determined. Maximum angiokinase activity was found at the molecular weight 61,000, high activities at 30,500 and 120,000, and traces of activity at 15,000, 45,700, and 76,000. Presumably angiokinase is the product of polymerization of a basic unit (mol. weight 30,500) or its subunit (mol. weight 15,000).
The Defibrination Syndrome in Rabbits Following Infusion of Tissue Thromboplastin in the Jugular Vein
Authors: Albkechtsen O. K , Brakman P , Astrup T
Published: June 2018

The effects of infusion of homologous tissue thromboplastin in the jugular vein of the rabbit was followed by determination of levels of coagulation factors in samples of blood obtained from the systemic arterial circulation by appropriate one-stage methods. The presence of active coagulation components was studied by appropriate two- or three-stage methods. There was marked consumption of coagulation factors, including fibrinogen. No macroscopically visible thrombi were seen in the major vessels of the systemic circulation indicating absence of tissue thromboplastin in the greater circulation. Two-and three-stage tests indicated presence of coagulation enhancing agents different from tissue thromboplastin and of a serum-like nature. Tissue thromboplastin, being bound to particulate matter, was most probably retained in the capillary bed of the lungs, thereby being prevented from appearing in the systemic circulation. The results confirm our previous findings obtained by infusion in the femoral vein. They are discussed and compared with the behavior of infused blood or tissue thromboplastin reported by other authors. Discrepancies in reported data could be traced to differences in sites of infusion or of collection of samples of blood. Changes in plasminogen concentration or in plasma euglobulin fibrinolytic activity on normal and heated fibrin plates were slight.
Streaming Potential
Authors: Edmark K.W , Davis J , Milligan H.L
Published: June 2018

Bioelectric charge transfer at the blood-wall interface may be a crucial factor affecting thrombosis on implant materials. The in-vitro streaming potential test technique offers a very sensitive, yet simple, means for observing this interfacial electrokinetic charge phenomena. Particular attention to test control variables is required, however, to obtain valid, comparative results. Due to the dynamic, changing nature of some surfaces on the molecular scale, reproducibility of results is subject to question and necessitates repeated runs to gain assurance of results.

It is demonstrated that this method of evaluation is an extremely sensitive tool in the study of blood-surface inter-actions. Changes in streaming potentials are dramatically revealed upon introduction of minute quantities of blood protein elements and drugs affecting blood coagulation. The techniques for applying this test method to the study of thrombosis are illustrated.

Streaming potential testing is a possible tool for realizing quality control in the preparation of anti-thrombogenic materials for cardiovascular implants. It may serve as a check, both on the formation of a proper surface and on the stability of this surface under physiological environment conditions.
Preparation and Properties of Human Prothrombin Complex
Authors: Tishkoff G. H , Williams L. C , Brown D. M
Published: June 2018

As a corollary to our previous studies with bovine prothrombin, we have initiated a study of human prothrombin complex. This product has been isolated in crystalline form as a barium glycoprotein interaction product. Product yields were reduced compared to bovine product due to the increased solubility of the barium glycoprotein interaction product. On occasion the crystalline complex exhibited good yields. The specific activity of the crystalline complex was 1851 Iowa u/mg. Further purification of human prothrombin complex was made by removal of barium and by chromatography on Sephadex G-100 gels. The final product evidenced multiple procoagulant activities (II, VII, IX and X). The monomeric molecular weight determined by sedimentation equilibrium in a solvent of 6 M guanidine-HCl and 0.5% mercaptoethanol was 70,191 ± 3,057 and was homogeneous with respect to molecular weight. This product was characterized in regard to physical constants and chemical composition. In general, the molecular properties of human prothrombin complex are very similar to the comparable bovine product. In some preparations a reversible proteolytic enzyme inhibitor (p-aminophenylarsonic acid) was employed in the ultrafiltration step of the purification scheme to inhibit protein degradation.
Coagulation Studies in 45 Cases of Nephrotic Syndrome without Uremia
Authors: Kanfer A , Kleinknecht D , Broyer M , Josso F
Published: June 2018

Coagulation studies were performed in 45 cases of nephrotic syndrome without uremia. The most striking features were an increase in the number of thrombocytes, and in the level of fibrinogen, factor V and factor VIII. Thrombin time was usually prolonged and the titre of antithrombin III was increased. No fibrin breakdown products were found in the serum. 13 patients developed thrombotic complications, with eventual death in 5 cases.
Simultaneous Development of Platelet Factor 4 Activity and Release of 14C-Serotonin
Authors: Harada K , Zucker Marjorie B.
Published: June 2018

Development of platelet factor 4 activity induced under various conditions by ADP, epinephrine, or connective tissue correlated well with release of 14C-serotonin measured simultaneously. In many ways connective tissue behaved differently from ADP and epinephrine, e.g., it caused PF-4 activity and 140-serotonin release in unstirred platelet-rich plasma and was effective in platelet-rich plasma from a thrombasthenic patient whereas ADP and epinephrine were not.
Plasminogen-Fibrinogen Complex Formation as a Prelude to Fibrinogenolysis
Authors: Ball Anne P. , Silver D , Day Eugene D.
Published: June 2018

Reproducible density-gradient ultracentrifugation reference profiles of the ratezonal type were established individually for radioiodinated fibrinogen, plasminogen, and urokinase. Two- and three-component radioiodinated mixtures were then studied to determine whether stable complexes would form between any two components and thus change the density-gradient distribution profiles.

Urokinase did not form stable complexes with plasminogen, fibrinogen, or fibrin, nor with any plasminogen-fibrinogen or plasminogen-fibrin mixtures.

Plasminogen was found to form stable complexes with fibrinogen and with fibrin. Urokinase added to such mixtures resulted in fibrinogenolysis and fibrinolysis, but not in stable urokinase binding.

The data support the proposition that urokinase does not activate plasminogen directly but requires the formation of plasminogen-fibrin(ogen) complexes as a prelude (conformational change?) to plasmin conversion and subsequent fibrin(ogen)olysis.
Die Plasma-Transglutaminase-Aktivität bei angeborenem totalem und partiellem Faktor-XIII-Mangel
Authors: Egbring R , Andrassy K , Egli H
Published: June 2018

Patienten mit totalem Faktor-XIII-Mangel besitzen weder im Plasma noch in den Thrombozyten eine meßbare Transglutaminase-Aktivität.

Heterozygote Krankheitsträger weisen als Ausdruck eines partiellen Faktor-XIII-Mangels eine verminderte Plasma-Transglutaminase-Aktivität auf.

Nach Substitution von Blut oder Fraktion I nach Cohn steigt die Plasma-Transglutaminase-Aktivität an und ermöglicht eine ausreichende Fibrinstabilisierung.

Auch nach Substitution zeigen die Thrombozyten bei Patienten mit Faktor-XIII-Mangel keine Transglutaminase-Aktivität.

Durch Messung der Plasma-Transglutaminase-Aktivität konnten wir unsere früheren Befunde bei 2 Familien mit kongenitalem totalem bzw. partiellem Faktor-XIII-Mangel bestätigen.
Prothrombin Utilization in Congenital Coagulation Deficiency States
Authors: Owen Ch. A , Thompson J. H
Published: June 2018

The disappearance of plasma prothrombin was measured during the spontaneous clotting of whole blood from 15 normal adults, from patients lacking fibrinogen, factor V, VII, VIII, IX, X, XI, XII, or XIII, or Fletcher factor, from patients with von Willebrand’s disease or Glanzmann’s thrombasthenia, and from one patient with an unidentified prothromboplastic abnormality. Prothrombin utilization was normal in patients lacking fibrinogen or factor VII or XIII or who had Glanzmann’s thrombasthenia. Utilization was most abnormal in patients with the greatest deficiencies of factors V, VIII, IX, or XI. Patients lacking factor XII or Fletcher factor consumed prothrombin rapidly after an abnormal initial lag period. Within each group of patients with hemophilia A or von Willebrand’s disease, the lower the concentration of factor VIII the more slowly was prothrombin utilized, but with von Willebrand’s disease there was much more rapid prothrombin utilization than with hemophilia with higher levels of factor VIII. Patients with the most pronounced deficiencies of factor XI, factor XII, or Fletcher factor had abnormal platelet adhesiveness.
Aktivitätssteigerungen verminderter Gerinnungsfaktoren bei angeborenen Gerinnungsdefekten
Authors: Mingers A.-M , Mietens C , Ströder J
Published: June 2018

Bei 17 Personen mit Gerinnungsstörungen wurden Plasmatauschversuche und Immunglobulinbestimmungen im Serum mit folgenden Ergebnissen durchgeführt :

1. Es besteht eine signifikante Aktivitätssteigerung des betreffenden Faktors in vitro bei Hämophilie A und B sowie kongenitalem Defekt im Prothrombinkomplex.

2. Keine Aktivitätssteigerung in vitro, sondern das Bild eines echten Faktorenmangels fand sich bei nicht hämophiliebedingter Faktor VIII-Minderung, erworbenem Defekt im Prothrombinkomplex und kongenitaler Afibrinogenämie.

3. Im Serum aller Patienten, bei denen im Plasmatauschversuch sich eine Aktivitätssteigerung des Mangelfaktors zeigte, waren über den 2-σ-Bereich hinaus erhöhte Konzentrationen eines oder mehrerer Immunglobuline, besonders IgM, nachweisbar.

4. Patienten, deren Plasmatauschversuche das Bild reinen Faktorenmangels boten, zeigten eher normale oder verminderte Immunglobulinwerte.
Major Surgery in a Subject with Factor V Deficiency
Authors: Melliger E. J , Duckert F
Published: June 2018

A further case of parahaemophilia is reported. One year after the correct diagnosis had been made the patient had to undergo cholecystectomy which was performed under prophylactic substitutive treatment with fresh plasma at a factor V level of 31 %. A minimal factor V level of 11 to 12% was maintained throughout the first week after operation. There was no abnormal postoperative bleeding. The half disappearance time of factor V was found to be about 12 h. Infusion of equivalent amounts of fresh plasma supplied a higher yield of factor V in the patient’s plasma before operation than postoperatively what may be explained by an increased diffusion of factor V into the intercellular space resulting from a postoperatively increased capillar permeability. The results are compared with those of other authors.
Ontogenesis of Tissue Plasminogen Activator in the Human
Authors: Åstedt B , Pandolfi M
Published: June 2018

The ontogenesis of tissue plasminogen activator in various tissues was studied in 10 embryos and 58 foetuses with a histochemical method.

The first appearance of activator activity was seen in a 4-weeks old embryo. At 8-9 weeks it was seen in the eye, meninges, heart, lungs, kidney and vena cava. In the foetal heart high activity was found in the coronary vessels, which can be regarded as the vasa vasorum of the heart. In the lungs a moderate activity increased at 24 weeks of age, when vascularisation increases more rapidly. Intense activity was seen in the highly vascularized corneoscleral junction of the eye later involved in the drainage of aqueous humor.

In the kidney the activity could be related to the vessels, while no activity was seen in the glomeruli, the collecting system or the pelvis. In the vessels the activator activity was fairly high. No activity was seen in any stage of development of the liver.

The plasminogen activator activity may be of importance for maintaining the foetomaternal circulation and micro-circulation in rapidly growing foetal organs. In the embryo the enzyme pattern is dominated by protein synthetizing enzymes. During foetal development the enzyme pattern changes owing to supervention of enzymes necessary for the function of the various organs. Plasminogen activator belongs to this latter group. The appearance of plasminogen activator activity may therefore be regarded mainly as a sign of functional maturity of the foetal organs.
In Vitro Platelet Reaction with Isolated Glomerular Basement Membrane
Authors: Ts'ao Chung-Hsin
Published: June 2018

Purified canine glomerular basement membrane (BM) induced platelet aggregation when added to heparinized platelet-rich plasma (PRP) of the rat. Platelet aggregation induced by BM suspension was compared with that induced by collagen submicroscopically. When aliquots of BM or collagen suspension of the same concentration (2 mg/ml saline) was incubated with PRP, platelet-BM reaction was far less pronounced than platelet-collagen reaction. Platelet-BM reaction was slow and aggregates were small; swelling and pseudopod formation were obvious but platelet degranulation was limited. With high concentration (5 mg/ml saline) of BM suspension, the aggregation time was shortened and aggregates were generally composed of larger number of platelets. Treatment of BM with collagenase abolished the platelet-BM reaction. It is postulated that similar “platelet aggregating” elements in collagen are present in BM; but the quantity of these elements is less in a BM than in a collagen molecule.
Homeopathy and Weather Conditions
Authors: Schrijvers Hanneke
Published: June 2018

Weather conditions can play an important role in causing suffering for those who are sensitive to it. Without addressing this with the indicated remedy, the suffering can change into a more severe disease condition.
Homeopathy for All Seasons
Authors: Jain Pratik , Chunawala Aafreen
Published: June 2018

In this article, several conditions are listed that are strongly influenced by the season. Weather-related remedies are discussed based on Sarkar's ‘Clinical Keynotes’.
A New Hybrid Technique for Performing a Safer Bilateral Sagittal Split Osteotomy: Combining Reciprocating Saw and Piezoelectric Devices
Authors: Raffaini Mirco , Perello Raffaella , Conti Marco , Hernandèz-Alfaro Federico , Agostini Tommaso
Published: June 2018

The sagittal split osteotomy (SSO) is an indispensable tool in the correction of dentofacial abnormalities. In elective orthognathic surgery, it is important that surgeons inform patients about the risk of complications related to inferior alveolar nerve damage and unfavorable split. The purpose of this article is to describe a novel, hybrid technique to SSO by combining a reciprocating saw and piezoelectric devices with several advantages over traditional “pure” methods (osteotomies performed by reciprocating saw or piezoelectric devices only) in terms of precision, rapidity, easier splitting, and decreased complications related to inferior alveolar nerve damage and bad split with reduced overall morbidity. The level of evidence was Level IV, therapeutic study.
Prophylactic Hypogastric Artery Ligation during Placenta Percreta Surgery: A Retrospective Cohort Study
Authors: Kuhn Theresa , Martimucci Kristina , Al-Khan Abdulla , Bilinski Robyn , Zamudio Stacy , Alvarez-Perez Jesus
Published: June 2018

Objective To evaluate if prophylactic hypogastric artery ligation (HAL) decreases surgical blood loss and blood products transfused.

Study Design This is a retrospective cohort study comparing patients with placenta percreta undergoing prophylactic HAL at the time of cesarean hysterectomy versus those who did not. Data were presented as means ± standard deviations, proportions, or medians with interquartile ranges. Demographic and clinical data were compared in the groups using Student's t-test for normally distributed data or the Mann–Whitney U test for nonnormally distributed data. Fisher's exact test was used for proportions and categorical variables. Data are reported as significant where p was <0.05.

Results There were 26 patients included in the control group with no HAL and 11 patients included in the study group. Estimated blood loss for the study group was 1,000 mL versus 800 mL in the control. Units of PRCBs transfused were 4.5 units in the study group versus 2 units for the control group. None of these measures were found to be statistically significant.

Conclusion Our data suggest there was no benefit in the use of prophylactic HAL in decreasing surgical blood loss or amount of blood products transfused in patients who had a cesarean hysterectomy performed for placenta percreta.

Précis Prophylactic HAL does not decrease blood loss during surgery for placenta percreta.
Iterated elliptic and hypergeometric integrals for Feynman diagrams
Authors: Ablinger J. , Blümlein J. , De Freitas A. , van Hoeij M. , Imamoglu E. , Raab C. G. , Radu C.-S. , Schneider C.
Published: June 2018

We calculate 3-loop master integrals for heavy quark correlators and the 3-loop quantum chromodynamics corrections to the ρ-parameter. They obey non-factorizing differential equations of second order with more than three singularities, which cannot be factorized in Mellin-N space either. The solution of the homogeneous equations is possible in terms of 2F1 Gauß hypergeometric functions at rational argument. In some cases, integrals of this type can be mapped to complete elliptic integrals at rational argument. This class of functions appears to be the next one arising in the calculation of more complicated Feynman integrals following the harmonic polylogarithms, generalized polylogarithms, cyclotomic harmonic polylogarithms, square-root valued iterated integrals, and combinations thereof, which appear in simpler cases. The inhomogeneous solution of the corresponding differential equations can be given in terms of iterative integrals, where the new innermost letter itself is not an iterative integral. A new class of iterative integrals is introduced containing letters in which (multiple) definite integrals appear as factors. For the elliptic case, we also derive the solution in terms of integrals over modular functions and also modular forms, using q-product and series representations implied by Jacobi’s ϑi functions and Dedekind’s η-function. The corresponding representations can be traced back to polynomials out of Lambert–Eisenstein series, having representations also as elliptic polylogarithms, a q-factorial 1/ηk(τ), logarithms, and polylogarithms of q and their q-integrals. Due to the specific form of the physical variable x(q) for different processes, different representations do usually appear. Numerical results are also presented.
Excitation of electromagnetic whistler waves due to a parametric interaction between magnetosonic and lower oblique resonance modes in a cold, magnetized plasma
Authors: Main D. , Sotnikov V. , Caplinger J. , Rose D. V.
Published: June 2018

We have studied the parametric interaction between a fast magnetosonic (FM) mode and a lower oblique resonance (LOR) mode in a cold, magnetized plasma using a kinetic, three dimensional Particle-in-Cell simulation code called the Large Scale Plasma. The FM mode is excited with a loop antenna driven at a frequency below the lower hybrid frequency (ωLH), while the LOR is excited at a frequency above ωLH. For historical purposes explained in the Introduction, we call the antennas which drive the FM mode and LOR mode Extremely Low Frequency (ELF) and Very Low Frequency (VLF) antennas, respectively. The antennas are modeled as magnetic dipoles (ρant = 0) and are assigned a time varying current density within a finite sized current loop. The VLF and ELF antennas are driven at 10 A and 3 A, respectively. The parametric interaction is excited with a combined ELF/VLF antenna (which we call a parametric antenna) and includes both antennas driven simultaneously in the same simulation domain. We show that the parametric antenna non-linearly excites electromagnetic (EM) whistler waves to a greater extent than the VLF antenna alone. We also show that the parametric excitation of EM whistler waves leads to greater emitted EM power (measured in Watts) compared with a VLF antenna alone.
Series-parallel grouping modeling simulation and experimental analysis of zinc-nickel single flow batteries
Authors: Yao Shouguang , Liu Wei , Cheng Jie , Shen Yaju
Published: June 2018

This study investigates a battery system with a zinc-nickel single flow battery (ZNB) stack by a series-parallel-connected system based on a two-order Thévenin equivalent circuit model for single-cell stack and parameter identification of the experimental model. Two single-cell stacks are simulated with three kinds of series-parallel battery pack equivalent circuit models, and compared with the experimental data. The results show that the simplified equivalent circuit model can accurately characterize the voltage of discharge for the series-parallel battery pack. The relative errors of the series/parallel battery pack are 0.8% and 0.71%. Furthermore, the simulation and experimental test data of the large-scale series-parallel system are compared, thereby indicating that the simplified equivalent circuit model of the series/parallel battery based on the two-order Thévenin model can provide a high-precision prediction for the external characteristics of a large-scale ZNB energy storage system.
Benchmarking acid and base dopants with respect to enabling the ice V to XIII and ice VI to XV hydrogen-ordering phase transitions
Authors: Rosu-Finsen Alexander , Salzmann Christoph G.
Published: June 2018

Doping the hydrogen-disordered phases of ice V, VI, and XII with hydrochloric acid (HCl) has led to the discovery of their hydrogen-ordered counterpart ices XIII, XV, and XIV. Yet, the mechanistic details of the hydrogen-ordering phase transitions are still not fully understood. This includes, in particular, the role of the acid dopant and the defect dynamics that it creates within the ices. Here we investigate the effects of a wide range of acid and base dopants on the hydrogen ordering of ices V and VI with calorimetry and X-ray diffraction. Surprisingly, lithium-hydroxide doping achieves a performance comparable to hydrofluoric-acid doping in ice V, but it is ineffective in the case of ice VI. Ice V is therefore the first phase of ice that can be hydrogen-ordered with both acid and base doping. Hydrobromic-acid doping facilitates hydrogen ordering of ice VI, but it is ineffective in the case of ice V. HCl is reaffirmed to be the most effective for both phases which is attributed to a favorable combination of high solubility and strong acid properties. Sodium-hydroxide, potassium-hydroxide (as previously shown), and perchloric-acid doping are ineffective for both phases. These findings highlight the need for future computational studies but also raise the question why lithium hydroxide is the best-performing alkali hydroxide for hydrogen-ordering ice V whereas potassium-hydroxide doping is most effective for the “ordinary” ice Ih.
Improved magnetization and reduced leakage current in Sm and Sc co-substituted BiFeO3
Authors: Durga Rao T. , Raja Kandula Kumara , Kumar Abhinav , Asthana Saket
Published: June 2018

BiFeO3 (BFO) and Bi0.85Sm0.15Fe0.90Sc0.10O3 (BSFSO) ceramics were synthesized by conventional solid state route. X-ray diffraction measurements revealed that an orthorhombic Pnma structure evolved with a phase fraction of 84% in the rhombohedral R3c structure of BFO upon the substitution of Sm and Sc. The changes in the intensity and the frequency of Raman modes also corroborated the structural transformation in the BSFSO compound. A decrease in grain size, reduction in porosity, and improved density were observed in the BSFSO compound. An enhanced remanent magnetization of 0.2 emu/g and coercive field of 6.2 kOe were observed, which were attributed to the structural change as well as the destruction of the spin structure with the substitution. Impedance and leakage current measurements revealed that the insulating character of BFO was improved with the substitution of Sm and Sc in BFO and was explained based on the bond enthalpy concept. The enhanced magnetic properties along with the improved insulating character of BSFSO compound will be suitable for device applications.
Onset of miscible and immiscible fluids’ invasion into a viscoplastic fluid
Authors: Zare M. , Frigaard I. A.
Published: June 2018

We simulate fluid invasion into a gelled cement slurry using a scaled laboratory experiment. This process is relevant to the construction of oil and gas wells, in which a tall column of cement suspension must resist fluid invasion through a combination of static pressure, yield stress, and interfacial tension. The sufficiently over-pressured fluids may enter from the surrounding rocks, leading to failure of the well integrity. Here, we model the cement suspension using a Carbopol solution (yield stress fluid) and apply different over-pressured invading fluids through a centrally positioned hole at the bottom of the circular column. We study water, glycerin, silicon oil, and air as invading fluids, in order to delineate the effects of yield stress, interfacial tension, and column height on fluid invasion. We find that the invasion is easiest for miscible fluids that penetrate locally at significantly lower invasion pressures than immiscible fluids. Viscosity affects this process by retarding the initial diffusive mixing of the fluids, which tends to weaken the gel locally. More viscous invading fluids require larger invasion pressures and result in larger invasion domes. The silicon oil penetrated in the form of a slowly expanding dome, resisted at the walls of the column – effectively by a Poiseuille flow above it in the Carbopol. Invasion pressures were significantly larger than those for the glycerin solutions. The largest invasion pressures were, however, found for air, which is influenced approximately equally by interfacial tension and yield stress.
Electron swarm parameters and Townsend coefficients of atmospheric corona discharge plasmas by considering humidity
Authors: Chen Xiaoyue , He Wangling , Du Xinyu , Yuan Xiaoqing , Lan Lei , Wen Xishan , Wan Baoquan
Published: June 2018

Humidity is a critical factor in atmospheric corona discharge. Fluid dynamics models have become a common method to explore the detailed corona discharge characteristics in humid air. However, the models require the specification of some key parameters, such as electron swarm parameters and Townsend coefficients, which strongly depend on the electron energy distribution function (EEDF). In this paper, the EEDFs of dry air and water vapor are compared by solving the electron Boltzmann equation using classical the two-term approximation. Moreover, electron drift velocity in dry air and water vapor are compared and validated. Finally, effects of humidity on the electron swarm parameters and Townsend coefficients are also discussed. The results show that the electron drift velocity in dry air and water vapor in this paper is well consistent with the previous experimental results for a wide range. It is concluded that the humidity could increase the electron mobility coefficient and decrease the electron diffusion coefficient in low reduced electric field, which are insensitive to humidity in high reduced electric field. The strength of ionization and attachment reactions are both enhanced by humidity, and the corona onset electric fields increase with the increase in humidity.
Effect of external turbulence on the short-wavelength instability of a counter-rotating vortex pair
Authors: Tunkeaw Jiratrakul , Rojanaratanangkule Watchapon
Published: June 2018

The effect of background turbulence on the evolution and instability of a counter-rotating vortex pair is investigated via the use of direct numerical simulation at a circulation Reynolds number of 2400. The ambient turbulence is modelled as decaying homogeneous isotropic turbulence with the initial levels of turbulence intensity (Tu) varied from 0.0% to 10.0%. The major effect of the external turbulence during the early-time development is that it reduces the vortex separation distance, leading to the mutual interaction of the two vortices. The onset to transition is also found to occur earlier. For a low-level turbulence intensity (Tu ≤ 6.25%), the vortex pair breaks down to turbulence due to the short-wavelength elliptic instability, whose characteristic is qualitatively similar to that in a quiescent background despite exhibiting a shorter wavelength. Increasing the turbulence intensity results in a decrease in the growth rate of the elliptic mode. The long-wavelength Crow mode dominates the breakdown process of the flow once Tu ≥ 7.5%. The Crow instability gives rise to the vortex disconnection and reconnection, resulting in the transformation of the vortex pair into a vortex ring.
Diffuse vacuum arc on cerium dioxide hot cathode
Authors: Usmanov R. A. , Amirov R. Kh. , Gavrikov A. V. , Liziakin G. D. , Polistchook V. P. , Samoylov I. S. , Smirnov V. P. , Vorona N. A. , Yartsev I. M.
Published: June 2018

A diffuse (spotless) vacuum arc was investigated on a hot cathode made from cerium dioxide. The discharge is obtained in the following range of current, voltage, and cathode temperature of I = 15–150 A, Va = 9–14 V, and Tc = 2.1–2.4 kK. The main characteristics of the plasma flow in space behind the anode with a hole were determined: it was found that the electron temperature at the working parameters lies in the range of 0.4–1 eV, the ions are predominantly singly charged, the average charge of the outgoing heavy particles reaches 0.9 e (elementary charge), and the most probable kinetic energy of the ions does not exceed 9 eV. Potentially found regimes of vacuum arc operation are promising for use in the work on implementation of the plasma method for spent nuclear fuel and/or radioactive waste reprocessing.
First-principles calculations of iron-hydrogen reactions in silicon
Authors: Santos Paulo , Coutinho José , Öberg Sven
Published: June 2018

Controlling the contamination of silicon materials by iron, especially dissolved interstitial iron (Fei), is a longstanding problem with recent developments and several open issues. Among these, we have the question whether hydrogen can assist iron diffusion or if significant amounts of substitutional iron (Fes) can be created. Using density functional calculations, we explore the structure, formation energies, binding energies, migration, and electronic levels of several FeH complexes in Si. We find that a weakly bound FeiH pair has a migration barrier close to that of isolated Fei and a donor level at Ev +  0.5 eV. Conversely, FeiH2(0/+) is estimated at Ev + 0.33 eV. These findings suggest that the hole trap at Ev + 0.32 eV obtained by capacitance measurements should be assigned to FeiH2. FesH-related complexes show only deep acceptor activity and are expected to have little effect on minority carrier life-time in p-type Si. The opposite conclusion can be drawn for n-type Si. We find that while in H-free material Fei defects have lower formation energy than Fes, in hydrogenated samples Fes-related defects become considerably more stable. This would explain the observation of an electron paramagnetic resonance signal attributed to a FesH-related complex in hydrogenated Si, which was quenched from above 1000 °C to iced-water temperature.
Inserting test particles improves measurements of structure and thermodynamics of fluids
Authors: Fellet Melissae
Published: June 2018

Analysis of experimental and simulation data using a new method allows for improved measurements of the microscopic structure of fluids that can be used to calculate their thermodynamic properties.
Hofstadter’s butterfly confirms a new tie between physics and mathematics
Authors: Patrick Chris
Published: June 2018

A researcher finds novel connections between Hofstadter’s butterfly and the mathematical conjecture known as the Langlands program.
Tensile properties of seminal and nodal roots and their relationship with the root diameter and planting density of maize (Zea mays)
Authors: Liu Sheng-qun , Li Xiang-nan , Zhu Xian-can , Song Feng-bin
Published: June 2018

The tensile property of roots is an important factor for anchorage and for resistance to root lodging. In this study, a root tensile test was applied to maize (Zea mays L.) grown in the field at three planting densities, 4.5 × 104, 6.75 × 104 and 9.0 × 104 plants ha–1, to quantify the maximum tensile force (Fmax) and tensile strength (Ts) of roots at the V10 stage (tenth leaf visible) and grain-filling stage. In addition, relationships among tensile properties, diameter and turgid weight : dry weight (TW : DW) ratio of roots were investigated. The results showed that the Fmax of primary and seminal adventitious roots was lower than of nodal roots. Among nodal roots, the Fmax of roots on upper nodes was higher. Planting density significantly affected the tensile force of nodal roots of the sixth to eighth tiers; their Fmax decreased with increasing planting density. A positive linear correlation between Fmax and root diameter and a power function between Ts and root diameter was observed. In addition, there was a positive linear correlation between the TW/DW ratio and root diameter and a negative exponential correlation between Ts and TW : DW ratio. Therefore, nodal roots with a lower TW : DW ratio could have a larger Ts, because their cells are smaller and cell walls are thicker. This result suggests that nodal roots with small and thick cells benefit the tensile properties of maize.
Valuation of knowledge and ignorance in mesolimbic reward circuitry
Authors: Charpentier Caroline J. , Bromberg-Martin Ethan S. , Sharot Tali
Published: June 2018

Significance

Humans desire to know what the future holds. Yet, at times they decide to remain ignorant (e.g., reject medical screenings). These decisions have important societal implications in domains ranging from health to finance. We show how the opportunity to gain information is valued and explain why knowledge is not always preferred. Specifically, the mesolimbic reward circuitry selectively treats the opportunity to gain knowledge about favorable, but not unfavorable, outcomes as a reward to be approached. This coding predicts biased information seeking: Participants choose knowledge about future desirable outcomes more than about undesirable ones, vice versa for ignorance, and are willing to pay for both. This work demonstrates a role for valence in how the human brain values knowledge.
Immunogenetic and structural analysis of a class of HCV broadly neutralizing antibodies and their precursors
Authors: Aleman Fernando , Tzarum Netanel , Kong Leopold , Nagy Kenna , Zhu Jiang , Wilson Ian A. , Law Mansun
Published: June 2018

Significance

Hepatitis C virus (HCV) infects 1–2% of the world’s population, but a vaccine to limit spreading of this silent killer is unavailable. A leading strategy in vaccine design to counter the genetic variability of HCV is to elicit broadly neutralizing antibodies (bnAbs) targeting conserved viral epitopes. The HCV antigenic site 412–423 (AS412) is highly conserved and a prime vaccine target. In this study, the genetic and structural properties of murine bnAbs targeting AS412 were determined. Using specific molecular interactions encoded in the antibody germline genes and those acquired by somatic hypermutation, two distinct antibody lineages recognize AS412 in near identical conformations. The results provide key insights in the development of HCV bnAbs for rational vaccine design.
The processes of animation and de-animation in conceptualizing socio-political events
Authors: Cibulskienė Jurga
Published: June 2018

The philosophical idea of anthropocentrism viewing human beings as the most significant entities has been put forward in various metaphor studies within cognitive linguistics. As Talmy (2002) claims, people choose to animate a very large part of their reality and this happens due to embodiment, as Lakoff (1987), and Lakoff and Johnson (1999) argue. Anthropocentricity can also be explained by Croft’s Extended Animacy Hierarchy system (2002) in terms of human beings outranking animate and inanimate entities, strongly implying that inanimate entities tend to be perceived as inferior. However, this paper argues that anthropocentrism is bidirectional, since not only do we ascribe human or animate qualities to inanimate objects or phenomena, but we also tend to “de-animate” human beings by attributing inanimate qualities to them. This paper further explores the idea of anthropocentricity by focusing on the metaphorical conceptualization of issues concerning the euro adoption in 2015 and the refugee crisis in 2015–2016, two real-life phenomena that have significantly affected social life in Lithuania. The paper thus aims to investigate how animation of the euro and de-animation of refugees is metaphorically conceptualized in the Lithuanian media and what rhetorical implications arise from this. The research is conducted within the framework of Critical Metaphor Analysis (Charteris-Black, 2005/2011, 2014; Musolff, 2004; Hart 2010, etc.), which suggests that metaphors are used as an argumentative tool seeking to manipulate the audience. The paper therefore argues that the animation of the euro and “de-animation” of refugees carry serious rhetorical implications and reveal the attitudes of society towards the phenomena analyzed.
“It’s so vital to learn Slovene”
Authors: Pokorn Nike K. , Čibej Jaka
Published: June 2018

Short-time migrants, who stay in the host country from one to 12 months, use mediation strategies including lingua francas, public-service interpreting and translation, translation technologies, intercomprehension, and learning the host country’s dominant language. The choices made by asylum seekers in Slovenia, a country of transit for the majority of asylum seekers, are analyzed on the basis of questionnaires answered by 127 current and former residents of the Slovene asylum seeker centers in 2016, followed up by semi-structured interviews with a representative group of 34 asylum seekers. The results show that the majority of newly arrived migrants regard the use of lingua francas as a helpful but not desired long-term strategy. They define host-country language learning as the most desirable strategy for linguistic and social inclusion. Surprisingly, they are reluctant to use translation technologies and interpreters because they either doubt the accuracy of the transfer or they consider such mediation (interpreting in particular) a hindrance to their independence.
Mediation choice in immigrant groups
Authors: Ayvazyan Nune , Pym Anthony
Published: June 2018

An interview survey of 51 members of Russian-speaking groups in the Salou area of southern Catalonia indicates the use of several modes of mediation to solve language problems. Professional written translators tend to be employed for official documents and high-risk situations only, whereas professional interpreters tend not to be used; family members and friends are usually preferred. There is widespread learning of Spanish, which is seen as the “host” language and offers independence, but very limited engagement with Catalan, which nevertheless remains a strong language of identification for much of the host society. In this multilingual context, Spanish, Russian, and English can all function as lingua francas depending on the situation. Russian, however, is only taught by private associations, even though its presence in the public school system could conceivably help address the diffuse sense of social exclusion felt by these groups and would be to the long-term benefit of the area’s economy, which partly depends on Russian tourism.