bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Whole Blood Flow Cytometric Detection of Platelet Bound Fibrinogen on Normal Subjects and Patients with Activated Platelets
Authors: Janes Sarah L , Wilson Darren J , Chronos Nicolas , Goodall Alison H
Published: July 2018

Activated platelets can be detected by measuring platelet-bound fibrinogen in a whole blood, flow cytometric assay, using a fluorescently-conjugated polyclonal antibody.

Fibrinogen binding to unstimulated platelets from normal subjects was low in this assay, as was expression of the CD63 antigen. Single cell counting of samples prepared for flow cytometric analysis showed platelet aggregates do not form during the assay procedure. Immune complexes were not seen, and fibrinogen binding to the platelets was unaffected by the CD32 MAb, IV.3. Artefactual activation of the unfixed samples could be minimised by control of phlebotomy, time and temperature of incubation. Variations in platelet count in the range 140–430 × 109 1-1 and in plasma fibrinogen in the range 2–6 g 1-1 did not affect the assay results.

Comparison of fibrinogen binding with expression of CD63 antigen on normal platelets, stimulated with agonists in vitro, demonstrated that fibrinogen binding detects an earlier stage of platelet activation.

Platelet bound fibrinogen was shown to be sensitive in detecting small numbers of activated platelets in clinical samples in twelve patients on intensive care, four undergoing haemofiltration. The patients had a significantly higher median percentage of circulating platelets with bound fibrinogen (p <0.005), but fibrinogen binding was significantly lower (p <0.02) in response to 10-5 M ADP, compared to twelve age-matched normal Controls.
Heparin Cofactor II Deficiency in Patients Infected with the Human Immunodeficiency Virus
Authors: Toulon P , Lamine M , Ledjev I , Guez T , Holleman M E , Sereni D , Sicard D
Published: July 2018

In human plasma, heparin cofactor II (HCII) is a thrombin inhibitor, whose deficiency has been reported to be associated with recurrent thrombosis. The finding of two cases of low plasma HCII activity in two patients infected with the human immunodeficiency virus (HIV) led us to investigate this coagulation inhibitor in the plasma of a larger population of HIV-infected patients. The mean plasma HCII activity was significantly lower in 96 HIV-infected patients than in 96 age- and sex-matched healthy individuals (0.75 ± 0.24 vs 0.99 ± 0.17 U/ml, p <0.0001). HCII antigen concentration was decreased to the same extent as the activity. The proportion of subjects with HCII deficiency was significantly higher in the HIV-infected group than in healthy individuals (38.5% vs 2.1%). In addition, HCII was significantly lower in AIDS patients than in other HIV-infected patients, classified according to the Centers for Disease Control (CDC) on the basis of an absolute number of circulating CD4+ lymphocytes below 200 x 106/1. The link between HCII and immunodeficiency is further suggested by significant correlations between HCII activity and both the absolute number of CD4+ lymphocytes and the CD4+ to CD8+ lymphocyte ratio. Nevertheless, the mean HCII level was not different in the various groups of patients classified according to clinical criteria, except in CDC IVD patients in whom HCII levels were significantly lower. In addition, no correlation could be demonstrated between HCII and protein S activities, another coagulation inhibitor whose plasma level was also found to be decreased in HIV-infected patients. A similar prevalence of HCII deficiency was also found in a small series of 7 HIV-infected patients who developed thrombotic episodes, an unusual complication of the infection. This suggests that, in HIV-infected patients, HCII deficiency is not in itself the causative factor for the development of thrombosis.
Platelet Hyperactivation in Patients with Essential Thrombocythemia Is not Associated with Vascular Endothelial Cell Damage as Judged by the Level of Plasma Thrombomodulin, Protein S, PAI-1, t-PA and vWF
Authors: Bellucci S , Ignatova E , Jaillet N , Boffa M C
Published: July 2018

The occurrence of thrombotic events remains an important clinical problem in Essential Thrombocythemias (ET). Thus, hemostatic, fibrinolytic and vascular status was investigated in 16 patients (5 males and 11 females) with ET. Among them five presented thromboses in their past history. Platelet hyperactivation, as evidenced by a mean three-fold increase in plasma betathromboglobulin (βTG), was observed in 13 among 16 patients; surprisingly this activation was present even when the platelet count was normal (in two patients) or subnormal, below 600 x 109/1 (in 11 patients). The mean value was 104 ± 57 IU/ml significantly different from that of normal controls (35 ± 16.5 IU/ ml) (p <0.001). An artefactual in vitro platelet activation was ruled out by the concomitant measurement of platelet factor, 4 (PF4). D-dimers fibrin degradation products (D-Di FDP) were normal in all patients. Vascular endothelial cell function parameters were not markedly modified. The mean value of plasma thrombomodulin ™ was found slightly but not significantly increased (60.1 ±4.9 ng/ml versus 49.1 ± 10.0 ng/ml in controls). The values of plasma TM correlated neither with that of the platelet count nor with that of plasma βTG or plasma PF4. The mean values of plasma protein S, von Willebrand factor (vWF), plasminogen activator inhibitor type 1 (PAI-1), tissue plasminogen activator (tPA) were normal and were not correlated neither with that of plasma TM nor with that of plasma βTG. In spite of a significant increase in vWF in two patients who presented peripheral thromboses, the markers of vascular endothelial cell function were not significantly different in patients having presented or not thromboses. Thus, in ET, these data showed the presence of platelet hyperactivation, even in patients in remission; it was not associated with vascular endothelial cell damage which might account for a greater risk of thrombosis.
Comparison of a Standardized Procedure with Current Laboratory Practices for the Detection of Lupus Anticoagulant in France
Authors:   Working Group on Hemostasis of the Société Française de Biologie Clinique
Published: July 2018

A multicenter study involving 13 laboratories was designed to compare a common procedure for screening lupus anticoagulants (LA) to the different practices currently in use in these laboratories. The common procedure combined 3 phospholipid- dependent assays, including mixing studies and a phospholipid neutralizing test. Due to the heterogeneity of LA expression, an abnormal result in at least one of the tests was sufficient to classify a sample as positive for LA. Consecutive samples referred for LA diagnosis were evaluated in parallel by each participant and the data found using the common procedure were analyzed independently according to mutually agreed cut-offs and criteria for sample classification. Within a period of 3 months, 535 samples were included, of which 147 were judged LA positive, 29 undetermined and 359 negative by the respective laboratories using their current practice. When using the common procedure, 149 plasmas were said to be positive, 38 undetermined and 348 negative. Absolute concordance occurred for 81% of the specimen population and absolute discordance (positive versus negative) for 7%. The level of agreement between the common procedure and the current practices, assessed by kappa indexes, indicated noticeable variations in the rates of detection from laboratory to laboratory. Among the different tests used in the common procedure, regular APTT was the least sensitive (about 50% detection) but none of the other tests alone recognized more than 73% of specimens from the LA positive population. This yield increased to about 90% with any combination of 2 sensitive tests. The common procedure should not be considered as a methodological gold standard but as an acceptable basis for the collaborative works required for the improvement and standardization of laboratory practices for screening LA.
Plasminogen-Activator in Human Early Milk: Its Partial Purification and Characterization
Authors: Okamoto Utako , Horie Noboru , Nagamatsu Yoko , Yamamoto Jun-Ichiro
Published: July 2018

Milk plasminogen-activator was partially purified from human transitional milk collected at about 10 days after delivery, by a five-step procedure involving chloroform treatment, ammonium sulfate precipitation, and column chromatography on Sephadex G-150, CM Sephadex C-50 and DEAE Sephadex A-50. This gave milk-activator with a maximum purification factor of about 2,400-fold with respect to the skimmed milk. The CM Sephadex-step preparation showed, on polyacrylamide gel electrophoresis, a single plasminogen-activator activity band located between the bands of albumin and prealbumin of human serum. This preparation exhibited no kinin forming activity. The activator hydrolyzed acetyl-glycyl-L-lysine methyl ester with similar order kinetic constants to urokinase, and was inhibited strongly by diisopropyl-fluorophosphate. The molecular weight of the activator as estimated by gel filtration was approximately 86,000, the isoelectric points as estimated by gel isoelectric focusing were pH 7.2, 6.9 and 6.6, and the activator activity was not quenched by antiurokinase globulin, indicating that the milk-activator is a different entity from urokinase.
The Clinical Usefulness of the Platelet Aggregation Test for the Diagnosis of Heparin-Induced Thrombocytopenia
Authors: Chong B H , Burgess J , Ismail F
Published: July 2018

The platelet aggregation test is widely used for the diagnosis of heparin-induced thrombocytopenia (HIT), a potentially serious complication of heparin therapy. We have evaluated its sensitivity and specificity in comparison with those of the 14C-serotonin release test. The sensitivity of the platelet aggregation test was found to vary with the heparin concentration and the donor of the platelets used in the test. The optimal heparin concentrations were between 0.1 and 1.0 U/ml. Using these heparin concentrations, the mean sensitivity varied from 39% (with the least reactive platelets) to 81% (with the most reactive platelets). In comparison, the sensitivity of the release test ranged from 65% to 94%. The specificities of the platelet aggregation test were 82%, 90% and 100% for the following control groups: (1) non-thrombocytopenic patients given heparin, (2) patients with thrombocytopenia due to other causes, and (3) normal controls not given heparin, respectively. The corresponding specificities for the release test was 94%, 90% and 100%. The specificities can be further increased to 100% for all controls with the adoption of a two-point system which defines a positive result as one in which platelet aggregation occurs with a low heparin concentration (0.5 U/ml) but not with 100 U heparin/ml. For optimal results, a two-point platelet aggregation test should be performed with heparin concentrations of 0.5 and 100 U/ml and using platelets of more reactive donors.
Kinetic Analysis of Bovine Factor VIII in the Hemophilic Dog
Authors: Gentry Patricia A , Kirby Edward P , Gentry Rodney D
Published: July 2018

Bovine factor VIII, which did not contain platelet aggregating factor activity, was infused into hemophilic dogs. Factor VIII procoagulant (VIII: C) levels in the dogs increased dramatically, then decreased in a biphasic manner. The half-life of the longest component was 3-7 hrs. The infusions were hemostatically effective and also caused a prolonged shortening of the activated partial thromboplastin time. These studies demonstrate that the platelet aggregating factor activity of bovine factor VIII is not essential for its maintenance in the circulation and that preparations lacking this activity may be clinically useful. When concentrates of partially purified factor VIII: C (essentially free of both platelet aggregating factor and factor VIII-related antigen) were infused, marked increases in VIII: C levels were also observed, but the half-life was significantly shorter (T1/2 of approximately 1 hr).
Antithrombin III Profiles in Malignancy, Relationship to Primary Tumors and Metastatic Sites
Authors: Honegger H , Anderson N , Hewitt L A , Tullis J L
Published: July 2018

Variations of antithrombin III were studied in a non-ran-domized population of consecutive cancer cases admitted to a referral hospital. Differences between functional and immunologic assay were observed.

Decreases were observed in both assays when compared to a population of hospitalized controls. Patients with cancer of the colon, ovary and prostate showed a deficiency of antithrombin III more frequently than other common tumors. When all tumor cases were subdivided into those in remission compared to those with metastases, a significant decrease in antithrombin III also could be shown.

Metastases to the liver were strikingly common in cancer patients with decreased antithrombin III. In these patients, the decrease in antithrombin III could be statistically correlated with reduction in serum albumin.
High Frequency of Low Plasma Haptoglobin Values Found in Hemophilia A Patients on Prophylactic Treatment with Factor VIII Concentrates - A Sign of Hemolysis?
Authors: Egberg Nils , Blombäck Margareta
Published: July 2018

Low plasma haptoglobin values have been observed in hemophilia A patients on regular prophylactic treatment with factor VIII concentrates. Two of 3 patients treated with fraction I-0 (Kabi) and 7 of 11 patients treated with high-purity concentrates (Hyland) had low haptoglobin values. Four of 8 patients who were treated with high-purity concentrates prescreened for a low content of anti-A and anti-B immunoglobulins still showed low haptoglobin levels. Unexpectedly, 2 patients of blood group 0 showed low haptoglobin values. The presence of irregular erythrocyte alloantibodies and/or other contaminants of the concentrates might thus also be a cause of hemolysis resulting in an increased consumption of haptoglobin.

Elevated lactate dehydrogenase levels were also frequent. No correlations were found between albumin, aspartate or alanine aminotransferase levels and haptoglobin levels.
The In Vitro Effect of Ticlopidine on Fibrinogen and Factor VIII Binding to Human Platelets
Authors: Lee Helen , Paton R C , Ruan C , Caen J P
Published: July 2018

The mode of action of the antiplatelet agent ticlopidine is not yet fully understood. Its multiple effects on platelet function include prolongation of the bleeding time, reduction in primary and secondary Waves of ADP-induced aggregation and inhibition of collagen and thrombin-induced aggregation. We have studied the in vitro effects of ticlopidine on fibrinogen binding induced by ADP and adrenaline as well as factor VIII/vWF binding induced by ristocetin.

125I-fibrinogen binding was measured in suspensions of freshly washed normal platelets stimulated by 10 μM ADP or 10 μM adrenaline. The binding of 125I-factor VIII/vWF in the presence of 1 mg/ml ristocetin was measured in both washed and paraformaldehyde-fixed platelets. Ticlopidine at final concentrations of 200, 100, 50 and 25 μM inhibited both ADP and adrenaline-induced fibrinogen binding in a dose-dependent manner. The mean % inhibition of ADP-induced fibrinogen binding was 82, 73, 42 and 32 respectively. The mean % inhibition of adrenaline induced fibrinogen binding was 86, 82, 60 and 35 respectively. In contrast, the factor VIII/vWF binding was unaffected by ticlopidine at all concentrations except at 200 μM using fresh platelets where a slight inhibition (19%) was observed.

These results suggest that ticlopidine either inhibits platelet activation and consequently fibrinogen binding, or inhibits the binding directly, presumably by having an effect on the specific configuration of the platelet membrane required for normal fibrinogen binding.
Changes in Factor VIII Complex Activities During the Production of a Clinical Intermediate Purity Factor VIII Concentrate
Authors: Prowse C V , Griffin B , Pepper D S , Dickson A J , McQuillan T A , Dickson I H , Foster P R
Published: July 2018

Samples taken at various stages of preparation of intermediate purity factor VIII concentrate were assayed for factor VIII coagulant activity (VIII:C), factor VIII coagulant antigen (VIIIC: Ag) and factor VIII related antigen (VIIIR: Ag). The antigen results were used to assess mechanical loss during fractionation as these markers are relatively stable. In contrast VIII:C is sensitive to both mechanical and inactivation losses.

The major loss of factor VIII occurred during the cryoprecipitation and extraction step and was due to both mechanical loss and inactivation. Losses before and after this step were largely due to inactivation of the factor VIII.

Assay of VIIIR: Ag in concentrates presented problems and a modified technique is suggested.
Platelet Aggregation, Malondialdehyde Generation and Production Time in Children with Sickle Cell Anaemia
Authors: Buchanan George R , Holtkamp Christine A
Published: July 2018

In view of prior reports of platelet activation in the sickling disorders, platelet aggregation, malondialdehyde (MDA) production following stimulation with N-ethylmaleimide, and/or production time (survival) measurements were examined in 44 children with homozygous sickle cell disease. Aggregation in response to epinephrine, collagen, and adenosine diphosphate was similar to or only slightly less than in normal black controls, rendering highly unlikely the circulation of a sizable population of refractory or “exhausted” platelets. The platelets from the normal blacks aggregated less in response to epinephrine than those from white control subjects. MDA generation in sickle cell platelets was not increased, and platelet production time was not shortened in 6 patients studied during crisis. These observations do not support the occurrence of a marked degree of platelet activation and consumption in sickle cell anaemia.
Weblog “How Do I Breathe?”—Design and View Statistics
Authors: de Luccas Gabriele , Berretin-Felix Giédre , Fukushiro Ana
Published: July 2018

Introduction Breathing is one of the vital functions of the body and is essential for the maintenance of life. Preventive measures for respiratory disorders can be used by the population, as well as early self-diagnosis and immediate search for treatment based on knowledge of this subject.

Objective this study developed a weblog on the breathing function targeting young people and analyzed the statistical data of views until the present moment.

Methods The weblog was developed, and the stages of analysis, design, development and implementation were followed. All texts were evaluated by the Flesch Reading Index to verify the language, and the statistical data were analyzed by the number of views, countries with the highest number of views, search terms used, most viewed pages and number of comments on the blog.

Results Issues related to the breathing function and those most cited in the literature were selected. The blog was structured using pages with content and curiosities, with texts with minimum readability of 50%, and was made available on the internet by means of the Wordpress tool. The statistics showed an increase in the number of visits after August 2015; the countries with the highest number of views were Brazil, United States and Portugal; the search terms used were unknown or related to mouth breathing; the most viewed pages related to mouth breathing and the comments addressed questions on mouth breathing, reports and compliments.

Conclusion The blog “How do I breathe?,” aimed at young people and containing information about the breathing function, was developed and is available on the internet at the address: https://comoeurespiro.wordpress.com.
The Effect of Fibroblast Growth Factors in Grafted Fascia into the Vocal Fold of Rabbits
Authors: Carvalho Eduardo , Machado-Júnior Almiro , Pauna Henrique , Nicola Ester , Altemani Albina , Crespo Agricio
Published: July 2018

Introduction The human larynx is a very important organ for communication. Many conditions lead to scarring of the vocal folds, decreasing voice quality.

Objective We aimed to determine whether fibroblast growth factors (FGFs) may influence tissue integration of grafted fascia into the vocal folds of an animal model.

Methods This is an experimental animal study with 12 adult rabbits that were submitted to a grafting fragment obtained from superficial cervical fascia into the vocal fold lamina propria, bilaterally. The right vocal fold was injected with FGFs. The animals were sacrificed after 1 month or 12 months, depending on the group they were assigned to, and a histological analysis of their vocal folds was performed. We analyzed the histological changes (such as the presence of fibrosis and neovascularization) induced by the acute or chronic inflammatory reactions.

Results The FGFs induced acute inflammatory changes in all animals after 1 month of the initial experiment. The presence of FGFs triggered more fibrosis than the expected due to the surgical procedure itself when compared with the control side of all animals after 12 months of the initial experiment.

Conclusions Fibroblast growth factors alone do not represent a good therapeutic option in phonosurgery, since we observed higher levels of fibrosis in the vocal fold lamina propria. Further studies combining more substances may be necessary to elucidate the best option to be used in this kind of surgery.
Room temperature plasmon-enhanced InAs0.91Sb0.09-based heterojunction n-i-p mid-wave infrared photodetector
Authors: Tong Jinchao , Tobing Landobasa Y. M. , Qiu Shupeng , Zhang Dao Hua , Unil Perera A. G.
Published: July 2018

Middle wavelength infrared (MWIR) photodetectors have a wide range of applications, but almost all of them operate at low temperature due to the limit of materials and device structures. The capability of plasmonic structures to localize electromagnetic wave on the deep subwavelength scale provides the possibility for MWIR photodetectors operating at room temperature. Here, we report a high sensitivity room temperature MWIR photodetector which is an InAs0.91Sb0.09-based heterojunction n-i-p photodiode integrated with a Au-based two-dimensional subwavelength hole array (2DSHA). A room temperature detectivity of 0.8 × 1010 cm Hz1/2 W−1 and a response time of 600 ns are achieved. The non-cooling high performance of 2DSHA-InAs0.91Sb0.09 based heterojunction photodetectors will make their applications easier, broader, and economic.
Degradation analysis of AlGaN/GaN high electron mobility transistor by electroluminescence, electric field-induced optical second-harmonic generation, and photoluminescence imaging
Authors: Katsuno Takashi , Manaka Takaaki , Soejima Narumasa , Ishikawa Tsuyoshi , Iwamoto Mitsumasa
Published: July 2018

The degradation positions in a Schottky gate AlGaN/GaN high electron mobility transistor device were visualized systematically by the complementary use of electroluminescence (EL), electric field-induced optical second-harmonic generation (EFISHG), and photoluminescence measurements in a single apparatus. The EL measurement clearly observed the degradation position, owing to its luminescence by the injection of hot carriers through the damaged AlGaN layer. On the other hand, EFISHG measurements suggested the weakening of the electric field at the degradation position. The degradation position was the gate edge on the drain side, and Ni residue like the particle was identified approximately 800 nm from the gate edge. The direct reason to degrade the device performances is the concentration of the electric field at the gate edge, and Ni residue would be the trigger of the degradation. Hot electrons could then easily tunnel through the inside of the damaged AlGaN barrier due to the formation of surface defects.
Structural analysis of sulfuric acid solutions containing Ti and Mn using x-ray diffraction, x-ray absorption fine structure, and molecular dynamics simulation
Authors: Tokuda Kazuya , Iihara Junji , Saito Yoshihiro , Masuno Atsunobu , Inoue Hiroyuki
Published: July 2018

Structural analyses have been performed for sulfuric acid (H2SO4) aqueous solutions containing Ti and/or Mn. These solutions are used as the positive electrolyte in the Ti–Mn redox flow (RF) battery, in which it had been found that adding Ti4+ in the positive electrolyte is very effective to reduce the MnO2 precipitation at a high state of charge. X-ray diffraction and x-ray absorption fine structure (XAFS) measurements were employed in order to obtain total correlation functions, T(r)’s, and coordination numbers around Mn and Ti in the solutions, respectively. The T(r)’s showed some peculiar peaks that were assigned to correspond to S—O, O—O, Mn—O, and Ti—O pairs in the solutions. The XAFS analysis demonstrated that both Mn and Ti have 6-coordinating oxygen atoms in the solutions. The classical molecular dynamics simulation was also carried out to obtain structural models of the solutions. By tuning the Born-Mayer type potential parameters, the T(r)’s calculated from the models showed good agreement with the experimental ones. Regarding the coordination number, the 6-coordinated Mn—O was reproduced successfully, while we need further investigation to find parameters that can reproduce the 6-coordinated Ti—O in the solutions. The simulation results also indicated the existence of Ti—SO4 bonds, which should promote the H+ dissociation from HSO4− and increase the H+ concentration in the solutions. This may be effective to suppress the MnO2 precipitation at a high state of charge in the RF battery.
Elastic Constants, Bulk Modulus, and Compressibility of H2O Ice Ih for the Temperature Range 50 K–273 K
Authors: Neumeier J. J.
Published: July 2018

Published elastic constant data for H2O ice in the Ih phase are compiled and evaluated. Fits of the five elastic constants for 50 ≤ T/K ≤ 273 are conducted to yield a reliable and convenient source for elastic constant values. Various elastic properties can be calculated from the elastic constants obtained herein. The elastic constants are used to determine the adiabatic bulk modulus BS for the same temperature range with an estimated uncertainty of less than 1.3%. Fitting those data yields an equation for BS that is extrapolated to provide values for 0 ≤ T/K < 50. The adiabatic compressibility KS, isothermal bulk modulus BT, and isothermal compressibility KT are calculated from BS. Comparisons are made to published data.
Transmission low-energy electron diffraction using double-gated single nanotip field emitter
Authors: Lee Chiwon , Tsujino Soichiro , Miller R. J. Dwayne
Published: July 2018

We explore the spatial coherence of double-gate single nanotip field emitters by low-energy electron diffraction experiments in transmission mode. By producing collimated field emission pulses from the single nanotip cathode and irradiating a suspended monolayer graphene film without additional optics, we observed sharper and higher resolution Bragg diffraction spots than a previous experiment using a nanotip array cathode. In particular, we found complete conservation of the size and the shape of the diffraction spots with those of the incident beam on the sample. The result indicates that the transverse coherence of a nanofabricated double-gate single-tip emitter is much larger than a few nanometers as determined by the apparent diffraction spot size and overall spatial resolution of the observed diffraction pattern.
An instrument for studying granular media in low-gravity environment
Authors: Aumaître S. , Behringer R. P. , Cazaubiel A. , Clément E. , Crassous J. , Durian D. J. , Falcon E. , Fauve S. , Fischer D. , Garcimartín A. , Garrabos Y. , Hou M. , Jia X. , Lecoutre C. , Luding S. , Maza D. , Noirhomme M. , Opsomer E. , Palencia F. , Pöschel T. , Schockmel J. , Sperl M. , Stannarius R. , Vandewalle N. , Yu P.
Published: July 2018

A new experimental facility has been designed and constructed to study driven granular media in a low-gravity environment. This versatile instrument, fully automatized, with a modular design based on several interchangeable experimental cells, allows us to investigate research topics ranging from dilute to dense regimes of granular media such as granular gas, segregation, convection, sound propagation, jamming, and rheology—all without the disturbance by gravitational stresses active on Earth. Here, we present the main parameters, protocols, and performance characteristics of the instrument. The current scientific objectives are then briefly described and, as a proof of concept, some first selected results obtained in low gravity during parabolic flight campaigns are presented.
Role of return currents in the dynamics of a magnetically rastered plasma torch
Authors: Goyal Vidhi , Ravi G. , Mukherjee S.
Published: July 2018

The role of return currents in the plasma dynamics of a dc non-transferred arc plasma torch has been investigated. The anode arc root connects the main plasma column and return current in the anode and its motion governs the return current formation in the anode. Thus by investigating the return currents, we can explore complex spatio-temporal evolution of the plasma in detail. In this work, we have used electrical and magnetic diagnostics. The electrical diagnostic comprises of a high voltage probe, and the magnetic diagnostic consists of a garland of several B-dot probes incorporated inside the anode water cooling channels. The magnetic (B-dot) probes are designed to pick up the dominant component of the time-varying magnetic fields. Results show that, beyond a threshold, volume return currents transform to constricted line currents in the anode return path. This is attributed to eddy currents arising due to space varying rather than time varying return current components in the anode. The probes capture fast rotation of the arc root that is not captured by fast imaging. Also, arc root shunting (restriking) phenomena and its location on the anode periphery are clearly captured by the garland of magnetic probes. A physical model explaining the processes is also presented.
Collisional excitation of interstellar CCN(X2Π) induced by He
Authors: Chefai A. , Khadri F. , Hammami K. , Lique F.
Published: July 2018

The CCN radical has been recently detected in the interstellar medium. Accurate modeling of its abundance in such media requires one to model its excitation by both radiation and collisions. Here, we report the first quantum mechanical close-coupling study of CCN—He collisions. Calculations of fine-structure resolved excitation cross sections of CCN(X2Π) induced by collision with He are performed for kinetic energies below 500 cm−1. The calculations are based on new two-dimensional potential energy surfaces obtained from coupled cluster approaches. We found that the inelastic cross sections for spin-orbit conserving transitions are larger than those for spin-orbit changing transitions. The new collisional data should significantly help the interpretation of interstellar CCN emission lines observed with current and future telescopes and we expect that they will allow accurate determination of the CCN abundance in the interstellar medium, which is crucial to understand the chemistry of carbon chain species in the interstellar gas.
Investigation of multipactor-induced surface plasma discharge and temporal mode transition
Authors: Sun Guang-Yu , Song Bai-Peng , Zhang Guan-Jun
Published: July 2018

Multipactor over a dielectric in vacuum inclines to engender interfacial gas desorption or evaporation, precipitating surface flashover and insulator failure. However, no consensus has been achieved regarding the exact mechanism during final breakdown stage, an expatiation of which therefore serves as our major motivation for this letter. By implementing the particle-in-cell simulation code, we investigate the microscopic evolution of the discharge development process and confirm the major component escalating the explosive space charge accumulation. The obtained current waveform validates the balance of charged particles between electrodes, corroborated by experimental results. A theoretical discharge model is then constructed to elucidate the physical reasoning of the previous phenomenon. Two distinct discharge modes are defined correspondingly, and the transition therein is found to be induced by rapid plasma density build-up.
Setting a course for marine mammal research in Western Australia
Authors: Waples Kelly , Raudino Holly
Published: July 2018

Given limited funding and increasing pressures on our natural resources it is becoming ever more critical that science be directed at improving our understanding and management of priority issues. This relies on dialogue and alignment between researchers and managers to ensure that appropriate questions are asked and the answers incorporated in robust and transparent decision-making processes which should include relevant evidence-based science. We used a prioritisation framework as a tool to bring managers and scientists together to discuss and agree on current priorities for research on marine mammals in Western Australia, including posing relevant questions. Eight species were identified as high priorities for fundamental research, including three dolphin species (Australian humpback, snubfin and common dolphin), three baleen whale species (Antarctic and pygmy blue and dwarf minke whale), the Australian sea lion and the dugong. The pressures we evaluated resulted in a priority need for research to better understand and mitigate impacts across a range of species, including noise pollution from shipping and vessel activity, climate change and fishing by-catch. Scientists and managers agreed on a set of topics and associated research questions for the high-priority species that would best inform ongoing conservation and management of marine mammals in Western Australia and that would have broad applicability nationally and globally. We provide an example of how these priorities can be used to develop a research program with targeted funding. Overall, this process has demonstrated the value of bringing scientists and managers together with a tool that allows them to jointly determine priorities and research questions.
The Politics of Action in Therapy
Authors: Rosen Alan
Published: July 2018

Any method of interpersonal learning or psychotherapy is always a sociopolitcal process, amongst other things, for better or for worse, and whether recognized as such or not. Creative action methods (such as psychodrama, art, dance therapy) in particular can enhance our sense of self and community, by amplifying our autonomy and our ability to do, individually and together. They provide a vivid metaphor for the impact our own actions can have on our lives outside the therapeutic or educational settings. But it is often difficult to get such work established and supported due to existing private and political interests within the professions. Many of the processes considered here are common to both psychotherapy and education. I dwell on therapy only as it is more familiar ground.
An Experimental Test of the Lucas Asset Pricing Model
Authors: Crockett Sean , Duffy John , Izhakian Yehuda
Published: July 2018

We implement a dynamic asset pricing experiment in the spirit of Lucas (1978) with storable assets and non-storable cash. In the first treatment, we impose diminishing marginal returns to cash to incentivize consumption smoothing across periods. We find that subjects use the asset to smooth consumption, although the asset trades at a discount relative to the risk-neutral fundamental price. This under-pricing is a departure from the asset price “bubbles” observed in the large experimental asset pricing literature originating with Smith et al. (1988) and can be rationalized by considering subjects’ risk aversion with respect to uncertain money earnings. In a second treatment, with no induced motivation for trade à la the Smith et al. design, we find that the asset trades at a premium relative to its expected value and that shareholdings are highly concentrated. Elimination of asset price uncertainty in additional experimental treatments serves to reinforce the same observations, and suggests that speculative behaviour explains the departure of prices from fundamental value in the absence of a consumption-smoothing motive for asset trades.
Fluoroquinolone resistance in Salmonella: insights by whole-genome sequencing
Authors: Cuypers Wim L. , Jacobs Jan , Wong Vanessa , Klemm Elizabeth J. , Deborggraeve Stijn , Van Puyvelde Sandra
Published: July 2018

Fluoroquinolone (FQ)-resistant Salmonella spp. were listed by the WHO in 2017 as priority pathogens for which new antibiotics were urgently needed. The overall global burden of Salmonella infections is high, but differs per region. Whereas typhoid fever is most prevalent in South and South-East Asia, non-typhoidal salmonellosis is prevalent across the globe and associated with a mild gastroenteritis. By contrast, invasive non-typhoidal Salmonella cause bloodstream infections associated with high mortality, particularly in sub-Saharan Africa. Most Salmonella strains from clinical sources are resistant to first-line antibiotics, with FQs now being the antibiotic of choice for treatment of invasive Salmonella infections. However, FQ resistance is increasingly being reported in Salmonella, and multiple molecular mechanisms are already described. Whole-genome sequencing (WGS) is becoming more frequently used to analyse bacterial genomes for antibiotic-resistance markers, and to understand the phylogeny of bacteria in relation to their antibiotic-resistance profiles. This mini-review provides an overview of FQ resistance in Salmonella, guided by WGS studies that demonstrate that WGS is a valuable tool for global surveillance.
Redesign of an Undergraduate General Microbiology Lab to Include Authentic Discovery-Driven Research on Cucumber Fermentations
Authors: Greenstein Jennifer , Ford Brian , Gove Sandra , Breidt Fred , Lee Alice , Taveirne Michael E.
Published: July 2018

Many undergraduate introductory microbiology laboratory courses teach basic principles of bacteriology using classical protocol-based experiments, with limited critical thinking and inquiry-based learning practices. We initiated a comprehensive redesign in our General Microbiology Laboratory course to promote scientific critical and creative thinking, while strengthening core microbiology concepts and skills. As part of the redesign, a series of authentic discovery-driven labs, based on cucumber fermentations, were developed as an independent research module within the course curriculum. Integrating discovery-driven labs allowed students to be engaged problem solvers, applying the scientific process to develop hypotheses, design experiments, utilize quantitative reasoning, and effectively communicate results. The inquiry-guided research project was developed to evaluate the minimum concentration of salt (NaCl) required in fermentation brine to safely, and effectively, ferment cucumbers. Over 5 weeks, students assess different aspects of the fermentation process, including quantifying bacterial populations with differential and selective media, measuring pH and glucose concentration of brine solutions, and characterizing the microbial metabolic potential. Additionally, students isolate an unknown bacterium from their fermentations, identifying and characterizing the isolate using 16S rRNA gene sequencing and metabolic tests. Throughout the research project, students collect, graph, and analyze their observations, culminating in students creating and presenting a scientific research poster. With this lab redesign, students generate new knowledge contributing to our understanding of microbial ecology within food fermentations, learn core microbiology skills and techniques, and develop critical and creative thinking skills. The impact of their research is valuable to science educators, researchers, and industry partners.
An Advancing Front of Old Age Human Survival
Authors: Zuo Wenyun , Jiang Sha , Guo Zhen , Feldman Marcus , Tuljapurkar Shripad
Published: July 2018

Old age mortality decline has driven recent increases in lifespans, but there is no agreement about trends in the age-pattern of old deaths. Some hypotheses argue that old-age deaths should have become compressed at high ages, others that old-age deaths should have become more dispersed with age, and yet others are consistent with little change in dispersion. However, direct analyses of old-age deaths presents unusual challenges: death rates at the oldest ages are always noisy; published life tables must assume an asymptotic age pattern of deaths; and the definition of “old age” changes as lives lengthen. Here we use robust percentile-based methods to overcome these challenges and show, for 5 decades in 20 developed countries, that old-age survival follows an advancing front, like a traveling wave. The front lies between the 25th and 90th percentiles of old-age deaths, advancing with nearly constant long-term shape but annual fluctuations in speed. The existence of this front leads to several predictions that we verify, e.g., that advances in life expectancy at age 65 are highly correlated with the advance of the 25th percentile, but not with distances between higher percentiles. Our unexpected result has implications for biological hypotheses about human aging, and for future mortality change.
McImpute: Matrix completion based imputation for single cell RNA-seq data
Authors: Mongia Aanchal , Sengupta Debarka , Majumdar Angshul
Published: July 2018

Motivation

Single cell RNA sequencing has been proved to be revolutionary for its potential of zooming into complex biological systems. Genome wide expression analysis at single cell resolution, provides a window into dynamics of cellular phenotypes. This facilitates characterization of transcriptional heterogeneity in normal and diseased tissues under various conditions. It also sheds light on development or emergence of specific cell populations and phenotypes. However, owing to the paucity of input RNA, a typical single cell RNA sequencing data features a high number of dropout events where transcripts fail to get amplified.

Results

We introduce mcImpute, a low-rank matrix completion based technique to impute dropouts in single cell expression data. On a number of real datasets, application of mcImpute yields significant improvements in separation of true zeros from dropouts, cell-clustering, differential expression analysis, cell type separability, performance of dimensionality reduction techniques for cell visualization and gene distribution.

Availability and Implementation

https://github.com/aanchalMongia/McImpute_scRNAseq
Modulation of corneal tissue mechanics influences epithelial cell phenotype
Authors: Gouveia Ricardo M. , Lepert Guillaume , Gupta Suneel , Mohan Rajiv R. , Paterson Carl , Connon Che J.
Published: July 2018

Whilst the control of stem cell differentiation using substrates of differing compliance has been extensively exploredin vitro, the significance of this mechanism at a physiological level is not known. Here we set to explore the role of corneal surface biomechanics in controlling epithelial cell proliferation and differentiation. Using non-contact high-resolution Brillouin spectro-microscopy we showed that the corneal outer edge (limbus) has significantly lower bulk modulus compared to the central cornea, and that this difference is precisely delimited in the organ. Furthermore, the areas of the limbus with distinctly softer properties were shown to be associated with limbal epithelial stem cell (LESC) residence. Based on these findings, we then provided the first demonstration of the capacity to modulate LESC phenotype, bothin vivoandex vivo, solely through the recreation/restoration of suitable biomechanical niches. These results thus confirm the fundamental role of corneal biomechanics in directing epithelial stem cell behavior.
Expansion of the fatty acyl reductase gene family shaped pheromone communication in Hymenoptera
Authors: Tupec Michal , Buček Aleš , Vogel Heiko , Janoušek Václav , Prchalová Darina , Kindl Jiří , Pavlíčková Tereza , Wenzelová Petra , Jahn Ullrich , Valterová Irena , Pichová Iva
Published: July 2018

The conserved fatty acyl reductase (FAR) family is involved in biosynthesis of fatty alcohols that serve a range of biological roles. In moths, butterflies (Lepidoptera), and bees (Hymenoptera), FARs biosynthesize fatty alcohol pheromones participating in mate-finding strategies. Using a combination of next-generation sequencing, analysis of transposable elements (TE) in the genomic environment of FAR genes, and functional characterization of FARs fromBombus lucorum, B. lapidarius, andB. terrestris, we uncovered a massive expansion of the FAR gene family in Hymenoptera, presumably facilitated by TEs. Expansion occurred in the common ancestor of bumblebees (Bombini) and stingless bees (Meliponini) after their divergence from the honeybee lineage. We found that FARs from the expanded FAR-A orthology group contributed to the species-specific male marking pheromone composition. Our results indicate that TE-mediated expansion and functional diversification of the FAR gene family played a key role in the evolution of pheromone communication in the crown group of Hymenoptera.

Abbreviations

MMP: male marking pheromone, FA: fatty acid, FAME: fatty acid methyl ester, FAR: fatty acyl reductase, LG: labial gland, FB: fat body, TE: transposable element.
Evidence for secondary-variant genetic burden and non-random distribution across biological modules in a recessive ciliopathy
Authors: Kousi Maria , Söylemez Onuralp , Ozanturk Aysegül , Akle Sebastian , Jungreis Irwin , Muller Jean , Cassa Christopher A. , Brand Harrison , Mokry Jill Anne , Wolf Maxim Y. , Sadeghpour Azita , McFadden Kelsey , Lewis Richard A. , Talkowski Michael E. , Dollfus Hélène , Kellis Manolis , Davis Erica E. , Sunyaev Shamil R. , Katsanis Nicholas
Published: July 2018

The influence of genetic background on driver mutations is well established; however, the mechanisms by which the background interacts with Mendelian loci remains unclear. We performed a systematic secondary-variant burden analysis of two independent Bardet-Biedl syndrome (BBS) cohorts with known recessive biallelic pathogenic mutations in one of 17 BBS genes for each individual. We observed a significant enrichment oftrans-acting rare nonsynonymous secondary variants compared to either population controls or to a cohort of individuals with a non-BBS diagnosis and recessive variants in the same gene set. Strikingly, we found a significant over-representation of secondary alleles in chaperonin-encoding genes, a finding corroborated by the observation of epistatic interactions involving this complexin vivo. These data indicate a complex genetic architecture for BBS that informs the biological properties of disease modules and presents a model paradigm for secondary-variant burden analysis in recessive disorders.