bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlled Multicenter Pilot Study of Urokinase – Heparin and Streptokinase in Deep Vein Thrombosis
Authors: van de Loo J C W , Kriessmann A , Trübestein G , Knoch K , de Swart C A M , Asbeck F , Marbet G A , Schmitt H E , Sewell A F , Duckert F , Theiss W , Ritz R
Published: July 2018

Thirty-three patients with acute iliofemoral thrombosis were randomly assigned to three treatment groups in a pilot doseranging study of thrombolytic therapy in deep vein thrombosis. One group received tissue culture urokinase in a dose of 2,200 I.U./kg/hr, and a second group in a dose of 1,100 I.U./kg/hr following a loading dose of 4,400 I.U./kg given in ten min. Urokinase was administered for 12 hr periods, alternating with 12 hr periods of heparin. A third group received an initial dose of 250,0001.U. of streptokinase in 20 min, followed by 100,000 I.U./hr. Treatment of all patients continued for three days. At the end of this period little improvement, evaluated by “blinded” interpretation of pre- and post-treatment phlebograms, was found in five out of ten of the higher-dose urokinase patients, seven out of eleven of lower-dosage urokinase patients, and six out of ten of streptokinase patients. Optional treatment for another three days showed little further improvement of urokinase-patients and moderate further improvement in the streptokinase-patients. – Neither of the 2 dosage schemes at intermittent application of urokinase appeared to be advantageous. Urokinase treated patients experienced fewer adverse reactions.
The Effects of Prostacyclin on the Coagulation of Whole Blood
Authors: Holloway D S , Zuckerman L , Vagher J P , Mockros L F
Published: July 2018

The effects of prostacyclin (PGI2) on mechanical properties of forming clots were investigated by testing human blood samples on a Thrombelastograph. Concentrations greater than 50 ng/ml (blood) caused a biphasic development of clot stiffness. During the first phase, PGI2 partially inhibited the platelet involvement in coagulation causing initial clot formation at a normal time but with reduced clot stiffness. The second phase occurred after neutralization of PGI2 activity and was characterized by recovery of platelet activity to produce a final clot with normal shear modulus. The duration of the inhibitory effects depended on PGI2 concentration and hematocrit. With a normal hematocrit, a PGI2 concentration of 60 ng/ml caused an inhibition for about 40 min whereas a concentration of 100 ng/ml caused inhibition for about 75 min.
Standardization of β-Thromboglobulin and Platelet Factor 4: A Collaborative Study to Investigate the Sources and Extent of Variation in the Measurement of Platelet Specific Proteins
Authors: Curtis A D , Kerry P J
Published: July 2018

A collaborative study involving seven laboratories has been carried out to investigate the sources and extent of variation in the measurement by radioimmunoassay of β-thromboglobulin (β-TG) and platelet factor 4 (PF4). Three plasma samples, one purified β-TG sample and two purified PF4 samples were assayed against house standards for the respective antigens by each laboratory.

The main source of variation of both β-TG and PF4 measurements was inter-assay (particularly for PF4). It was found that a significant component of this variation was due to the participants’ use of different preparations as house standards for β-TG and for PF4. This indicates that the first step in the standardization of β-TG and PF4 measurement should be the introduction of a reference for each.
A Collaborative Calibration Study of Reference Materials for Thromboplastins
Authors: Hermans J , van den Besselaar A M H P , Loeliger E A , van der Velde E A
Published: July 2018

In a collaborative study of ten laboratories performed mainly within the framework of the BCR (the European Community Bureau of Reference), five thromboplastins were calibrated against the WHO (World Health Organisation) primary international reference preparation 67/40. Of these five thromboplastins, three were BCR reference materials (BCT/099, OBT/79 and RBT/79) and two were WHO secondary international reference preparations (68/434 and 70/178). Human brain tissue type is represented by 67/40 and BCT/099; bovine type by 68/434 and OBT/79, and rabbit type by 70/178 and RBT/79.

The calibration relations are expressed in terms of a linear relationship between the logarithms of the prothrombin times, measured in seconds.
The Increase of Leg Fibrinolytic Potential After Reduction of Hydrostatic Stimulus
Authors: Keber Dušan
Published: July 2018

Eleven patients were studied sequentially from the beginning of recumbency due to trauma up to the complete mobilization. The first blood sampling was performed 12 hr to 4 days after injury, the second after 12 to 33 days of recumbency and the third after one or more months of mobilization. The blood was drawn each time before and after venous occlusion of the arm and the leg for 20 min. Fibrinolytic potential was calculated as the difference between post- and preocclusion values of plasminogen activator activity, measured with the euglobulin clot lysis time (ECLT) and on fibrin plates. The results showed that fibrinolytic potential of legs after the period of recumbency was approaching that of the arms, being ten times higher as measured with ECLT and five times higher as measured on fibrin plates in comparison with the period after mobilization. It was concluded that hydrostatic pressure was the main, if not the only factor responsible for the difference in the content of plasminogen activator in veins of arms and legs and their fibrinolytic potential.
The Combining Ability of Glycoproteins IIb, IIIa and Ca2+ in EDTA-Treated Nonaggregable Platelets
Authors: Zucker Marjorie B , Varon David , Masiello Nicholas C , Karpatkin Simon
Published: July 2018

Platelets deprived of calcium and incubated at 37° C for 10 min lose their ability to bind fibrinogen or aggregate with ADP when adequate concentrations of calcium are restored. Since the calcium complex of glycoproteins (GP) IIb and IIIa is the presumed receptor for fibrinogen, it seemed appropriate to examine the behavior of these glycoproteins in incubated non-aggregable platelets. No differences were noted in the electrophoretic pattern of nonaggregable EDTA-treated and aggregable control CaEDTA-treated platelets when SDS gels of Triton X- 114 fractions were stained with silver. GP IIb and IIIa were extracted from either nonaggregable EDTA-treated platelets or aggregable control platelets with calcium-Tris-Triton buffer and subjected to sucrose density gradient centrifugation or crossed immunoelectrophoresis. With both types of platelets, these glycoproteins formed a complex in the presence of calcium. If the glycoproteins were extracted with EDTA-Tris-Triton buffer, or if Triton-solubilized platelet membranes were incubated with EGTA at 37° C for 30 min, GP IIb and IIIa were unable to form a complex in the presence of calcium. We conclude that inability of extracted GP IIb and IIIa to combine in the presence of calcium is not responsible for the irreversible loss of aggregability that occurs when whole platelets are incubated with EDTA at 37° C.
Transcoronary Platelet Thromboxane A2 Formation without Platelet Trapping in Patients with Coronary Stenosis - Effect of Sulphinpyrazone Treatment
Authors: Cortellaro M , Boschetti C , Antoniazzi V , Moreo G , Repetto S , Verna E , Boscarini M , Limido A , Binaghi G , Polli E E
Published: July 2018

Platelet count, and plasma thromboxane B2 (TXB2) and circulating platelet aggregates (CPA) were determined in the coronary sinus (CS), aortic bulb (AO) and cubital vein (V) in 21 patients with stable angina and in 6 control subjects before and after atrial pacing (AP). TXB2 measurements were repeated before and after AP in 6 of the 21 angina patients after 15 days’ sulphinpyrazone treatment. Platelet count and CPA ratio were similar in angina patients and controls at all three sampling sites and were unchanged at AP peak. In the controls, basal TXB2 values in CS, AO and V were not significantly different and were unchanged at AP peak. In the angina patients compared with the controls, basal TXB2 values in the AO, CS and V were not significantly different whereas the CS/AO TBX2 ratio was significantly higher; at AP-induced ischaemia, CS TXB2 was significantly increased and the CS/AO TXB2 ratio was increased. A weak but significant direct correlation was found between CS/ AO TXB2 ratio and coronary score. Sulphinpyrazone treatment reduced CSTXB2 levels at rest and after AP, but not the ischaemic threshold at AP.
A Rapid One-Step Immunoradiometric Assay for Factor VIII-Procoagulant Antigen Utilizing Monoclonal Antibodies
Authors: Stel H V , Veerman E C I , Huisman J G , Janssen M C , van Mourik J A
Published: July 2018

A two-site immunoradiometric assay for factor VIII-procoagulant antigen (VIIICAg) that relies completely on monoclonal antibodies has been developed. By selecting an appropriate combination of these antibodies, it was possible to develop an assay in which the radiolabelled monoclonal antibody did not inhibit the binding of antigen to the solid-phase monoclonal antibodies. Thus, the entire test could be carried out as a one-step procedure. With this one-step assay, an amount of 0.0025 U VIIICAg/ml plasma could be detected after 4 hr of incubation, whereas 18 hr of incubation resulted in a lower limit of sensitivity of 0.0005 U VIIICAg/ml. The use of a one-step assay provides a significant advantage over the conventional two-step assay by simplifying, shortening and rendering the performance of the assay more convenient.
Perineal Trauma in a Low-risk Maternity with High Prevalence of Upright Position during the Second Stage of Labor
Authors: Peppe Mariana Vitor , Stefanello Juliana , Infante Bruna Fregonesi , Kobayashi Mauricio Tsuguio , Baraldi Claudia de Oliveira , Brito Luiz Gustavo Oliveira
Published: July 2018

Objective Perineal trauma is a negative outcome during labor, and until now it is unclear if the maternal position during the second stage of labor may influence the risk of acquiring severe perineal trauma. We have aimed to determine the prevalence of perineal trauma and its risk factors in a low-risk maternity with a high incidence of upright position during the second stage of labor.

Methods A retrospective cohort study of 264 singleton pregnancies during labor was performed at a low-risk pregnancy maternity during a 6-month period. Perineal trauma was classified according to the Royal College of Obstetricians and Gynecologists (RCOG), and perineal integrity was divided into three categories: no tears; first/second-degree tears + episiotomy; and third and fourth-degree tears. A multinomial analysis was performed to search for associated factors of perineal trauma.

Results From a total of 264 women, there were 2 cases (0.75%) of severe perineal trauma, which occurred in nulliparous women younger than 25 years old. Approximately 46% (121) of the women had no tears, and 7.95% (21) performed mediolateral episiotomies. Perineal trauma was not associated with maternal position (p = 0.285), health professional (obstetricians or midwives; p = 0.231), newborns with 4 kilos or more (p = 0.672), and labor analgesia (p = 0.319). The multinomial analysis showed that white and nulliparous presented, respectively, 3.90 and 2.90 times more risk of presenting perineal tears.

Conclusion The incidence of severe perineal trauma was low. The prevalence of upright position during the second stage of labor was 42%. White and nulliparous women were more prone to develop perineal tears.
Practice Variation in Antenatal Steroid Administration for Anticipated Late Preterm Birth: A Physician Survey
Authors: Clapp Mark , Boggess Kim , Kaimal Anjali , Snead Carrie , Schulkin Jay , Aliaga Sofia , Battarbee Ashley
Published: July 2018

Objective The objective of this study was to measure knowledge and practice variation in late preterm steroid use.

Study Design Electronic survey of American College of Obstetricians and Gynecologists (ACOG) members about data supporting the ACOG/Society for Maternal-Fetal Medicine (SMFM) recommendations and practice when caring for women with anticipated late preterm birth (PTB), 340/7 to 366/7 weeks.

Results Of 352 administered surveys, we obtained 193 completed responses (55%); 82.5% were generalist obstetrician-gynecologists (OB/GYNs), and 42% cared for women with anticipated late PTB at least weekly. Most believed that late preterm steroids provided benefit by reducing respiratory distress syndrome (93%), transient tachypnea of the newborn (83%), and neonatal intensive care unit admission (82%). More than half administered late preterm steroids to women with multiple gestations (73%), and pregestational diabetes (55–80%) depending on glycemic control. OB/GYNs administered steroids to insulin-dependent and poorly controlled diabetics more often than MFMs (75 vs. 46% and 59 vs. 37% respectively, p < 0.05 for both). While providers believed there was increased maternal hyperglycemia (88%) and neonatal hypoglycemia (59%), 88% believed neonatal respiratory benefits outweighed these risks. Respondents agreed research is needed to determine who are appropriate candidates (77%) and how to minimize adverse outcomes (82%).

Conclusion Most providers are administering late preterm steroids to all women, even those populations who have been excluded from previous trials. Despite widespread use, providers believe more research is needed to optimize management.
Real-Time Navigation-Guided Drilling Technique for Skull Base Surgery in the Middle and Posterior Fossae
Authors: Goto Tetsuya , Hara Yosuke , Hongo Kazuhiro , Ogiwara Toshihiro
Published: July 2018

Objective The usefulness of the bony surface registration method for navigation system image-guided surgery in the lateral or prone position has been reported. This study was performed to evaluate the efficacy of our new real-time navigation-guided drilling technique with bony surface registration for skull base surgery in the middle and posterior fossae.

Methods The study included 29 surgeries for skull base tumors that required drilling of the petrous bone between January 2015 and December 2017 in Shinshu University Hospital. A navigation system was used for drilling of the petrous bone as follows: (1) some labyrinthine structures were marked by color in the source image and superimposed on the navigation image on the workstation preoperatively; (2) bony surface registration was performed with a three-dimensional (3D) skull reconstruction model in the operating room; (3) the petrous bone was drilled under navigation guidance with real-time view-through confirmation of 3D color-marked labyrinthine structures with observation under a microscopic operative view.

Results Real-time identification of some structures in the petrous bone was performed, and adequate and precise drilling of the petrous bone was achieved without the risk of labyrinthine perforation or stress. Using this method, surgeons do not need to alternate their gaze between the surgical field and the navigation screen.

Conclusions Due to the development of bony surface registration, this new technique is useful for drilling petrous bone in the middle and posterior fossa skull base surgeries.
Risk of Developing Postoperative Deficits Based on Tumor Location after Surgical Resection of an Intracranial Meningioma
Authors: Ehresman Jeff , Garzon-Muvdi Tomas , Rogers Davis , Lim Michael , Gallia Gary , Weingart Jon , Brem Henry , Bettegowda Chetan , Chaichana Kaisorn
Published: July 2018

Object Meningiomas occur in various intracranial locations. Each location is associated with a unique set of surgical nuances and risk profiles. The incidence and risk factors that predispose patients to certain deficits based on tumor locations are unclear. This study aimed to determine which preoperative factors increase the risk of patients having new deficits after surgery based on tumor location for patients undergoing intracranial meningioma surgery.

Methods Adult patients who underwent primary, nonbiopsy resection of a meningioma at a tertiary care institution between 2007 and 2015 were retrospectively reviewed. Stepwise multivariate logistic regression analyses were used to identify associations with postoperative deficits based on tumor location.

Results Postoperatively, from the 761 included patients, there were 39 motor deficits (5.1%), 23 vision deficits (3.0%), 19 language deficits (2.5%), 27 seizures (3.5%), and 26 cognitive deficits (3.4%). The factors independently associated with any postoperative deficits were preoperative radiation (hazard ratio [HR] [95% confidence interval, CI] 3.000 [1.346–6.338], p = 0.008), cerebellopontine angle tumors (HR [95% CI] 2.126 [1.094–3.947], p = 0.03), Simpson grade 4 resections (HR [95% CI] 2.000 [1.271–3.127], p = 0.003), preoperative motor deficits (HR [95% CI] 1.738 [1.005–2.923], p = 0.048), preoperative cognitive deficits (HR [95% CI] 2.033 [1.144–3.504], p = 0.02), and perioperative pulmonary embolisms (HR [95% CI] 11.741 [2.803–59.314], p = 0.0009).

Conclusion Consideration of the factors associated with postoperative deficits in this study may help guide treatment strategies for patients with meningiomas.
Warfarin Quality Metrics for Hospitalized Older Adults
Authors: Cohen Jessica , Sinvani Liron , Wang Jason , Kozikowski Andrzej , Patel Vidhi , Qiu Guang , Pekmezaris Renee , Spyropoulos Alex
Published: July 2018

Background Warfarin's adverse drug events are dangerous, common, and costly. While outpatient warfarin management tools exist, there is a dearth of guidance for inpatients.

Objectives We sought to describe a health system's chronic warfarin quality metrics in older inpatients, defined by international normalized ratio (INR) control, explore associations between INR overshoots and clinical outcomes, and identify factors associated with overshoots.

Patients/Methods Data on patients 65 years and older who were prescribed chronic warfarin and admitted during January 1, 2014, to June 30, 2016, were extracted through retrospective chart review. We defined overshoots as INRs 5 or greater after 48 hours of hospitalization. Logistic regression modeling was used to determine risks for overshoots and multivariate analysis for overshoots' association with length of stay (LOS), bleeding, and mortality.

Results Of the 12,107 older inpatients on chronic warfarin, most were 75 years or older (75.7%), female (51.2%), and white (70.0%). While 1,333 (11.0%) of patients had overshoots during the admission, 449 (33.7%) of these reached overshoots after 48 hours. When stratified by overshoots versus no overshoots, LOS more than doubled (15.6 vs. 6.8 days) and the bleed rate was significantly higher (27.4 vs. 8.3%) in the overshoot group. While overall mortality was small (0.4%), the overshoot group's mortality was significantly higher (3.12 vs. 0.28%). Black race and weight were protective against overshoots; history of heart failure and antibiotic/amiodarone exposure were predictive of overshoots.

Conclusion This is the largest study examining warfarin quality metrics for hospitalized adults, specifically older inpatients. Our model may serve as the basis for identifying high-risk warfarin patients to target interventions to reduce adverse drug events.
Parkinson-Erkrankung und Neuroinflammation – Zelluläre Pathologie, Mechanismen und therapeutische Optionen
Authors: Tönges Lars , Metzdorf Judith , Zella Samis
Published: July 2018

Durch verfeinerte Untersuchungstechniken in der Neuropathologie, der präzisierten molekularen Charakterisierung von Biomaterialien und nuklearmedizinische Untersuchungen des ZNS bei Parkinson-Patienten sind sowohl in post mortem Analysen aber auch intravital zahlreiche Belege für eine relevante Beteiligung der Neuroinflammation zu finden. Nach Evaluation immer größerer und besser definierter Patienten-Kohorten hat sich zudem gezeigt, dass unterschiedliche neuroinflammatorische zelluläre Akteure involviert sind. Diese Zelltypen und ihre Funktionen wurden zum Verständnis der pathogenetischen Mechanismen der Parkinson-Erkrankung in Zellkultur- und Tiermodellen detailliert untersucht und bilden eine Grundlage für die Entwicklung translationaler therapeutischer Ansätze. In dieser Übersichtsarbeit wird der derzeitige Wissensstand über die Bedeutung der Neuroinflammation bei der Parkinson-Erkrankung mit Fokus auf die zelluläre Pathologie von Astrozyten, Mikroglia und T-Lymphozyten differenziert in Modellsystemen und beim Menschen dargestellt. Sich daraus ableitende therapeutische Optionen, deren humane Anwendbarkeit sowie das Potential zur Verlaufsbeeinflussung der Parkinson-Erkrankung sind enorm und werden abschließend diskutiert.
Patterning of graphene oxide with optoelectronic tweezers
Authors: Lim Matthew B. , Felsted Robert G. , Zhou Xuezhe , Smith Bennett E. , Pauzauskie Peter J.
Published: July 2018

Optoelectronic tweezers (OET) offer a means for parallel trapping and dynamic manipulation of micro-scale particles using low-intensity light. Such capabilities can facilitate the formation of bulk materials with a precisely tailored microstructure. Here, we report the use of OET to vertically align, trap, and reposition sheets of graphene oxide (GO) in liquids, paving the way for textured and patterned graphene macroassemblies that could offer superior performance for applications in energy storage, catalysis, and electronic devices. Trapping can be achieved with low-power light from inexpensive digital projectors and diode lasers, making it simple for users to create and apply patterns while avoiding undesirable photothermal heating effects. To give users a quantitative idea of trap stiffness, we also present a theoretical framework for predicting the maximum achievable speed of a GO platelet in an OET trap.
Electronic phase engineering induced thermoelectric enhancement in manganites
Authors: Jia Ping , Wang Yinlong , Yan Zhibo , Gong Jijun , Lin Lin , Gao Feng , Liu J.-M.
Published: July 2018

The nano-structuring engineering and the introduction of magnetic scattering are effective ways to enhance the thermoelectric performance. In this work, we use the magnetic treatments on La0.4Pr0.225Ca0.375MnO3 to demonstrate that the electronic phase engineering can enhance the thermoelectric performance by simultaneously reducing the thermal conductivity and raising the power factor in a strongly correlated electron system. This study indicates that the magnetic treatment changes the phase separation state and impedes the growth of ferromagnetic metal (FMM) phase. The reduction of FMM phase suppresses the bipolar effect, which raises the Seebeck coefficient and the power factor, reduces the thermal conductivity, and therefore enhances the thermoelectric performance.
Effect of non-thermality of electron and negative ion on the polarity of shock waves in a relativistic plasma
Authors: Dev Apul N. , Deka Manoj Kr.
Published: July 2018

Considering the effect of non-thermality of electrons and negative ions, the evolution of shock waves and their characteristics in a relativistic plasma is investigated by deriving a three-dimensional Burgers' (3D-Burgers') equation. Based on the stationary solution of the 3D-Burgers' equation, the nature of propagation of shock waves for different suitable physically admissible ranges of plasma parameters, is carried out. Both compressive and rarefactive shock waves are found to propagate in such plasma under different combinations of non-thermal plasma parameters. The critical values of non-thermal electron and negative ion parameters, normalized electron, and negative ion density under which the non-linear co-efficient vanishes is sought. The nature of propagation of shock waves, below, above, and at the critical parameters is carried out. The non-thermal population of negative ions and electrons as well as normalized electron and negative ion density plays a pivotal role in controlling the polarity of the shock wave propagation. Compressive and rarefactive shock is found to propagate simultaneously with the non-thermal population of negative ions for different chosen values of normalized negative ion density at the critical value of normalized electron density.
The so-called critical condition for polyelectrolyte-colloid complex formation
Authors: Comert Fatih , Xu Amy Y. , Madro Slawomir P. , Liadinskaia Vanda , Dubin Paul L.
Published: July 2018

Complexes formed between oppositely charged polyelectrolytes (PE’s) and either biological or abiotic colloid particles play a central role in such remarkably diverse areas as enzyme immobilization, protein purification, growth factor delivery, personal care products, food formulations and as precursors to coacervates and multilayers. Unlike PE adsorption on oppositely charged planar surfaces—also driven by electrostatics—PE-colloid complexes are often equilibrium states exhibiting reversible formation at a well-defined “critical” colloid surface charge density. We consider how the experimentally observed breadth of this transition, for three polyelectrolyte-colloid systems, is broadened—compared to theoretical expectations—due to (1) colloid (protein) charge anisotropy, (2) colloid (micelle) polydispersity, and (3) colloid (micelle) instability.
Rapid thermal anneal activates light induced degradation due to copper redistribution
Authors: Nampalli N. , Laine H. S. , Colwell J. , Vähänissi V. , Inglese A. , Modanese C. , Vahlman H. , Yli-Koski M. , Savin H.
Published: July 2018

While it is well known that copper impurities can be relatively easily gettered from the silicon bulk to the phosphorus or boron–doped surface layers, it has remained unclear how thermally stable the gettering actually is. In this work, we show experimentally that a typical rapid thermal anneal (RTA, a few seconds at 800 °C) used commonly in the semiconductor and photovoltaic industries is sufficient to release a significant amount of Cu species from the phosphorus-doped layer to the wafer bulk. This is enough to activate the so-called copper-related light-induced degradation (Cu-LID) which results in significant minority carrier lifetime degradation. We also show that the occurrence of Cu-LID in the wafer bulk can be eliminated both by reducing the RTA peak temperature from 800 °C to 550 °C and by slowing the following cooling rate from 40–60 °C/s to 4 °C/min. The behavior is similar to what is reported for Light and Elevated Temperature degradation, indicating that the role of Cu cannot be ignored when studying other LID phenomena. Numeric simulations describing the phosphorus diffusion and the gettering process reproduce the experimental trends and elucidate the underlying physical mechanisms.
Effects of pressure on the structure and lattice dynamics of ammonium perchlorate: A combined experimental and theoretical study
Authors: Kroonblawd Matthew P. , Koroglu Batikan , Zaug Joseph M. , Pagoria Philip F. , Goldman Nir , Greenberg Eran , Prakapenka Vitali B. , Kunz Martin , Bastea Sorin , Stavrou Elissaios
Published: July 2018

Ammonium perchlorate NH4ClO4 (AP) was studied using synchrotron angle-dispersive X-ray powder diffraction (XRPD) and Raman spectroscopy. A diamond-anvil cell was used to compress AP up to 50 GPa at room temperature (RT). Density functional theory (DFT) calculations were performed to provide further insight and comparison to the experimental data. A high-pressure barite-type structure (Phase II) forms at ≈4 GPa and appears stable up to 40 GPa. Refined atomic coordinates for Phase II are provided, and details for the Phase I → II transition mechanics are outlined. Pressure-dependent enthalpies computed for DFT-optimized crystal structures confirm the Phase I → II transition sequence, and the interpolated transition pressure is in excellent agreement with the experiment. Evidence for additional (underlying) structural modifications include a marked decrease in the Phase II b′-axis compressibility starting at 15 GPa and an unambiguous stress relaxation in the normalized stress-strain response at 36 GPa. Above 47 GPa, XRD Bragg peaks begin to decrease in amplitude and broaden. The apparent loss of crystalline long-range order likely signals the onset of amorphization. Three isostructural modifications were discovered within Phase II via Raman spectroscopy. A revised RT isothermal phase diagram is discussed based on the findings of this study.
Composition effect on thermophobicity of ternary mixtures: An enhanced molecular dynamics method
Authors: Antoun Sylvie , Saghir M. Ziad , Srinivasan S.
Published: July 2018

Thermodiffusion or the Ludwig-Soret effect is known as the cross effect between the temperature gradient and induced separation of mixture species in multicomponent mixtures. The performance of the boundary driven non-equilibrium molecular dynamics enhanced heat exchange (eHEX) algorithm was validated by evaluating the sign and magnitude of the thermodiffusion process in methane/n-butane/n-dodecane (nC1–nC4–nC12) ternary mixtures. The eHEX algorithm consists of an extended version of the HEX algorithm with an improved energy conservation property. In addition to this, the transferable potentials for phase equilibria-united atom augmented force field was employed in all molecular dynamics (MD) simulations to accurately represent molecular interactions in the fluid. Our newly employed MD algorithm was capable to appropriately reflect the thermophobicity concept and the coupled effect of relative density and mole fraction of the mixture species on the thermodiffusion process. The separation ratio of the ternary mixture for five different compositions (at 333.15 K and 35 MPa) showed good agreement with experimental data and better accuracy in predicting the sign change of the intermediate component (nC4) as its concentration in the mixture increases, when compared to other MD models.
Open or closed? Information flow decided by transfer operators and forecastability quality metric
Authors: Bollt Erik M.
Published: July 2018

A basic systems question concerns the concept of closure, meaning autonomy (closed) in the sense of describing the (sub)system as fully consistent within itself. Alternatively, the system may be nonautonomous (open), meaning it receives influence from an outside subsystem. We assert here that the concept of information flow and the related concept of causation inference are summarized by this simple question of closure as we define herein. We take the forecasting perspective of Weiner-Granger causality that describes a causal relationship exists if a subsystem's forecast quality depends on considering states of another subsystem. Here, we develop a new direct analytic discussion, rather than a data oriented approach. That is, we refer to the underlying Frobenius-Perron (FP) transfer operator that moderates evolution of densities of ensembles of orbits, and two alternative forms of the restricted Frobenius-Perron operator, interpreted as if either closed (deterministic FP) or not closed (the unaccounted outside influence seems stochastic and we show correspondingly requires the stochastic FP operator). Thus follows contrasting the kernels of the variants of the operators, as if densities in their own rights. However, the corresponding differential entropy comparison by Kullback-Leibler divergence, as one would typically use when developing transfer entropy, becomes ill-defined. Instead, we build our Forecastability Quality Metric (FQM) upon the “symmetrized” variant known as Jensen-Shannon divergence, and we are also able to point out several useful resulting properties. We illustrate the FQM by a simple coupled chaotic system. Our analysis represents a new theoretical direction, but we do describe data oriented directions for the future.
On the transverse dielectric permittivity of the collisionless plasmas with quantum effects
Authors: Bobrov V. B. , Maslov S. A. , Trigger S. A.
Published: July 2018

An expression is found for the transverse dielectric permittivity of a collisionless nonrelativistic fully ionized plasma, which consequently takes into account quantum effects in the presence of an intrinsic magnetic moment of plasma particles. The frequency and spatial dispersion of the dielectric permittivity under various thermodynamic parameters are investigated. The obtained dielectric permittivity is compared with the known theoretical results for a collisionless plasma in the classical limit.
Roles of heating and helicity in ultrafast all-optical magnetization switching in TbFeCo
Authors: Lu Xianyang , Zou Xiao , Hinzke Denise , Liu Tao , Wang Yichuan , Cheng Tuyuan , Wu Jing , Ostler Thomas A. , Cai Jianwang , Nowak Ulrich , Chantrell Roy W. , Zhai Ya , Xu Yongbing
Published: July 2018

Using the time-resolved magneto-optical Kerr effect method, helicity-dependent all-optical magnetization switching (HD-AOS) is observed in ferrimagnetic TbFeCo films. Our results reveal the individual roles of the thermal and nonthermal effects after a single circularly polarized laser pulse. The evolution of this ultrafast switching occurs over different time scales, and a defined magnetization reversal time of 460 fs is shown—the fastest ever observed. Micromagnetic simulations based on a single macro-spin model, taking into account both heating and the inverse Faraday effect, are performed which reproduce HD-AOS demonstrating a linear path for magnetization reversal.
Simulations of a polar molecule (sulfur dioxide) in a supersonic jet
Authors: Chen Guanglong , Boldarev A. S. , Li Xingjia , Cao Yunjiu , He Jianping , Kim Dong Eon
Published: July 2018

Clustering of polar molecules (SO2) in a supersonic jet was investigated by simulation. The cluster size Nc was calculated under different gas backing pressures P0 and source temperatures T0. Based on these results, the dependence of Nc on P0 or T0 was compared with that for the gases of non-polar molecules. It is found that SO2 molecules condense very easily into clusters even when P0 is very low. This result implies that large clusters can be produced using polar molecules, which could be useful in the studies of laser-cluster interactions. Also, SO2 gas is an important component of air pollution, so the knowledge of the clustering properties of SO2 could be helpful in the study of air pollution and environment.
Relaxation models for single helical reversed field pinch plasmas at low aspect ratio
Authors: Paccagnella R. , Masamune S. , Sanpei A.
Published: July 2018

A recent study [R. Paccagnella, Phys. Plasmas 23, 092512 (2016)] about the scaling with the aspect ratio (i.e., the ratio between the major and minor radius of the torus) of the dominant mode in single helical reverse field pinch plasmas has shown, at intermediate aspect ratio, that the dominant toroidal mode number in the helical states can be interpreted as the result of a relaxation process. In this work, the same theoretical model is compared and validated with the experimental data obtained in the low aspect ratio RELAX device [S. Masamune et al., J. Phys. Soc. Jpn. 76, 123501 (2007).]. Some difficulties have emerged in this comparison that may be interpreted either as related to a residual level of magnetic chaos in the RELAX plasmas or possibly to genuine toroidal effects not analyzed in this paper, where a cylindrical approximation is considered.
Predicting tipping points of dynamical systems during a period-doubling route to chaos
Authors: Nazarimehr Fahimeh , Jafari Sajad , Hashemi Golpayegani Seyed Mohammad Reza , Perc Matjaž , Sprott Julien Clinton
Published: July 2018

Classical indicators of tipping points have limitations when they are applied to an ecological and a biological model. For example, they cannot correctly predict tipping points during a period-doubling route to chaos. To counter this limitation, we here try to modify four well-known indicators of tipping points, namely the autocorrelation function, the variance, the kurtosis, and the skewness. In particular, our proposed modification has two steps. First, the dynamic of the considered system is estimated using its time-series. Second, the original time-series is divided into some sub-time-series. In other words, we separate the time-series into different period-components. Then, the four different tipping point indicators are applied to the extracted sub-time-series. We test our approach on an ecological model that describes the logistic growth of populations and on an attention-deficit-disorder model. Both models show different tipping points in a period-doubling route to chaos, and our approach yields excellent results in predicting these tipping points.
Scattering by the broadband electrostatic turbulence in the space plasma
Authors: Vasko I. Y. , Krasnoselskikh V. V. , Mozer F. S. , Artemyev A. V.
Published: July 2018

The broadband electrostatic turbulence that is produced by electrostatic solitary waves and associated with strong parallel currents is widely observed in the space plasma. In this paper, we develop a basis for quantifying particle scattering by the broadband electrostatic turbulence. We show that the pitch angle and energy scattering rates can be computed using the classical quasi-linear theory in spite of the fact that the turbulence is produced by nonlinear solitary waves. The developed formalism is applied to estimate the particle scattering rates by the broadband turbulence observed in the Earth's inner magnetosphere. We show that the scattering rates of ions are negligible, while the pitch-angle scattering of electrons is sufficiently fast to drive valuable electron losses to the atmosphere. The anomalous dissipation of a parallel current and anomalous electron heating by the broadband turbulence are evaluated.
Substitutional mechanism for growth of hexagonal boron nitride on epitaxial graphene
Authors: Mende Patrick C. , Li Jun , Feenstra Randall M.
Published: July 2018

Monolayer-thick hexagonal boron nitride (h-BN) is grown on graphene on SiC(0001), by exposure of the graphene to borazine, (BH)3(NH)3, at 1100 °C. The h-BN films form ∼2-μm size grains with a preferred orientation of 30° relative to the surface graphene. Low-energy electron microscopy is employed to provide definitive signatures of the number and composition of two-dimensional planes across the surface. These grains are found to form by substitution for the surface graphene, with the C atoms produced by this substitution, then being incorporated below the h-BN (at the interface between the existing graphene and the SiC) to form a new graphene plane.
Subsampled STEM-ptychography
Authors: Stevens Andrew , Yang Hao , Hao Weituo , Jones Lewys , Ophus Colin , Nellist Peter D. , Browning Nigel D.
Published: July 2018

Ptychography has been shown to be an efficient phase contrast imaging technique for scanning transmission electron microscopes (STEM). STEM-ptychography uses a fast pixelated detector to collect a “4-dimensional” dataset consisting of a 2D electron diffraction pattern at every probe position of a 2D raster-scan. This 4D dataset can be used to recover the phase-image. Current camera technology, unfortunately, can only achieve a frame rate of a few thousand detector frames-per-second (fps), which means that the acquisition time of the 4D dataset is up to 1000× slower than the scanning speed in a conventional STEM, thereby limiting the potential applications of this method for dose-fragile and dynamic specimens. In this letter, we demonstrate that subsampling provides an effective method for optimizing ptychographic acquisition by reducing both the number of detector-pixels and the number of probe positions. Subsampling and recovery of the 4D dataset are shown using an experimental 4D dataset with randomly removed detector-pixels and probe positions. After compressive sensing recovery, Wigner distribution deconvolution is applied to obtain phase-images. Randomly sampling both the probe positions and the detector at 10% gives sufficient information for phase-retrieval and reduces acquisition time by 100×, thereby making STEM-ptychography competitive with conventional STEM.
Designs and electric properties studied of 3D trench electrode Si detector with adjustable central collection electrode
Authors: Liao Chuan , Liu Manwen , Zhang Ya , Zhao Jun , Li Zheng
Published: July 2018

In order to improve the radiation resistance of semiconductor detector, 3D trench electrode Si detector structures have been proposed by the Brookhaven National Laboratory (BNL) in 2009. In this paper, we propose a 3D trench electrode Si detector with adjustable central collection electrode, which integrates advantages of cylindrical units and parallel units. For those combined units, we use 1D Poisson equation as the first order approximation to study the changing of depletion in different regions. These results have been compared to those obtained from the full 3D simulation using a 3D-TCAD tool. According to calculations, we design a 3D trench electrode Si detector with adjustable central collection electrode. Furthermore, electrical characteristics of this type of detectors with different lengths of central collection electrode (lp+) have been simulated using the 3D-TCAD. Regarded as the main factor of signal-noise ratio, the geometric capacitance obtained from Silvaco TCAD simulations is compared with which is calculated by physical models when detectors size varies. Finally, the physic model of charge collection is established using Ramo theorem. The CCE (Charge Collection Efficiency) of detector unit is studied with this model (after Φ=1016 neq/cm2, average CCE is 38%).
Adducts of transition metal complexes with redox-active ligands: the structure and spin-state-switching rearrangements
Authors: Starikova Alyona A. , Minkin Vladimir I.
Published: July 2018

The currently available literature data on the synthesis, molecular and electronic structure of mixed-ligand complexes (adducts) of transition metals (chromium, manganese, iron, cobalt, ruthenium) with organic redox-active ligands are systematically considered for the first time. The possibility of manifestation of magnetic bistability by adducts of tetracoordinate CoII and FeII complexes and the potential for their application as molecular switches are studied in detail by means of quantum chemical modelling of thermally initiated rearrangements controlled by the spin crossover and valence tautomerism mechanisms. Special attention is given to dinuclear adducts of CoII and FeII complexes with linearly bonded and polycyclic di-o-quinones and their imines, which can operate as thermally switchable elements of quantum computers suitable for practical implementation of two-qubit gates.

The bibliography includes 183 references.
Surface-Active Ionic Liquids in Catalytic Water Splitting
Authors: Cognigni Alice , Palvögyi Ádám Márk , Schröder Christian , Peterlik Herwig , Müllner Alexander R. M. , Zirbs Ronald , Weil Matthias , Bica Katharina
Published: July 2018

We report the application of surface-active ionic liquids as ligands and optional reaction media in iridium-catalyzed water oxidations. Three novel catalysts with N,N-dialkylimidazolidin-2-ylidene ligands based on amphiphilic imidazolium ionic liquids were synthesized and characterized. Excellent turn-over frequencies of up to 0.92s−1 were obtained in catalytic water splitting, and activity was maintained for five consecutive catalytic cycles, with an overall turn-over number of 8967. The addition of external surface-active ionic liquid showed unexpected behaviour, because strongly enhanced initial reaction rates were observed.
Magnetic and Optical Properties of Novel Lanthanide(III) Complexes Based on Schiff Base and β-Diketonate Ligands
Authors: Jia Yufeng , Li Hongfeng , Chen Peng , Gao Ting , Sun Wenbin , Yan Pengfei
Published: July 2018

A series of lanthanide-based self-assembling complexes constructed from Schiff base and β-diketonate ligands have been synthesised by the same method. They are one dimensional complexes ({[Ln(H2L)(tta)2(OAc)]·0.5H2O}n (Ln = Eu (1), Gd (2), Dy (3), Yb (4)); H2L = N,N′-bis(salicylidene)butane-1,4-diamine, tta = 2-thenoyltrifluoroacetone). Complexes 1 and 4 exhibit characteristic metal-centred emission in the solid state. The lifetimes and quantum yields of luminescence were also determined. Magnetic analysis reveals that complex 3 exhibits field-induced single-molecule magnet (SMM) behaviour with an energy barrier of 24.07 K.
Enhanced expression of MycN/CIP2A drives neural crest toward a neural stem cell-like fate: Implications for priming of neuroblastoma
Authors: Kerosuo Laura , Neppala Pushpa , Hsin Jenny , Mohlin Sofie , Vieceli Felipe Monteleone , Török Zsofia , Laine Anni , Westermarck Jukka , Bronner Marianne E.
Published: July 2018

Significance

Neuroblastoma is a neural crest-derived pediatric cancer that develops in the embryonic peripheral nervous system (PNS). Studies of PNS progenitors have failed to uncover how tumors initiate or fully recapitulate the most aggressive forms of the disease. Previous transcriptome analysis reveals similarity between some neuroblastoma samples and neural stem cells. Here, we show that ectopic expression of MycN in the neural crest domain of the developing neural tube biases neural crest stem cells toward a more CNS neural stem cell-like fate and thus results in improperly specified neural crest cells. This may play a role as a priming event for tumor initiation, thus providing useful insights into understanding the mechanism behind neuroblastoma formation.
Stress-testing the relationship between T cell receptor/peptide-MHC affinity and cross-reactivity using peptide velcro
Authors: Gee Marvin H. , Sibener Leah V. , Birnbaum Michael E. , Jude Kevin M. , Yang Xinbo , Fernandes Ricardo A. , Mendoza Juan L. , Glassman Caleb R. , Garcia K. Christopher
Published: July 2018

Significance

T cells recognize their targets through the T cell receptor (TCR). The affinity of a typical receptor for an agonist peptide-major histocompatibility complex (pMHC) molecule is extremely weak, and TCRs are known to be cross-reactive for related peptides. However, there are known TCR/pMHC interactions that occur at weaker affinities, such as in thymic selection and recognition of self-antigens, yet little is known about the identity of these peptides. We show that TCR/pMHC interactions of extremely low affinities remain highly specific, which informs of the nature of extremely weak affinity ligands. We also show that a peptide “velcro” can induce peptide-dependent T cell activation, providing a method for increasing the potency of a target, which is useful in immunotherapy.
Exopolysaccharide protects
Vibrio cholerae
from exogenous attacks by the type 6 secretion system
Authors: Toska Jonida , Ho Brian T. , Mekalanos John J.
Published: July 2018

Significance

This work demonstrates that exopolysaccharide (EPS) produced by
Vibrio cholerae
can protect against exogenous type 6 secretion system (T6SS) attacks from different bacterial species. This protection does not affect the ability of the EPS-producing cell to use their own T6SS to attack other bacteria, indicating that EPS does not simply increase the physical distance between cells to afford protection. Furthermore, this protective effect does not depend on other genes involved in biofilm biogenesis, suggesting that EPSs can determine the outcomes of antagonistic bacterial–bacterial interactions independent of their typical function in biofilm formation. Thus, extracellular biopolymers of bacteria may play a role in modulating resistance to exogenous attacks by other bacteria as well as providing potential resistance to host innate immune mechanisms.