bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi‐channel LED driver based on switched‐controlled capacitor with constant frequency control
Authors: Liu Junfeng , Tian Hanlei , Zeng Jun 
Published: June 2018

Current sharing among light‐emitting diode (LED) strings is significant for reliability and long life. The capacitive balancing was widely used with low losses and small volume. However, the capacitive balancing scheme adopting the impedance matching causes large circulating current, and its precision of current sharing is restricted due to impedance tolerance. In addition, the high reactive power with pulse frequency control brings high power stress on the volt‐ampere rating (VAR) of the half‐bridge switches and arouses heavy electro‐magnetic interference. In this study, the interleaved structure of the upper and lower half‐bridge is proposed to alleviate the mismatching of capacitance impedance. Besides, the wide range of LED dimming capability is accomplished by using the switched‐controlled capacitor (SCC) unit with the constant frequency of power switches. The circuit analysis, SCC modulation, current sharing, LED dimming and performance comparisons are examined in detail. All the superior performance of the proposed LED driver is verified by simulation prototype and experimental platform with four‐channel LED strings and rated power of 23 W. The accordance of theoretical analysis, simulation waveforms and experiment results further confirms the feasibility of the proposed LED driver.
Facile one‐step synthesis of SnS2 nanoscale hollow spheres for enhanced lithium‐ion storage performance as anode
Authors: Guo Yani , Wang Xiufeng , Shao Weizhi 
Published: June 2018

The SnS2 hollow nanospheres are successfully fabricated using SnCl4 ·5H2 O, thiourea and urea as raw materials via a mild one‐step hydrothermal process. The size of SnS2 hollow nanosphere is about 400 nm, and the shell thickness of it is about 50 nm, consisting of nanoparticles with the size of 3 nm. The formation of such hollow structure could be mainly ascribed to the soft template effect of carbon‐dioxide and ammonia bubbles decomposed from urea. The obtained hollow nanospheres possess a higher specific surface area of 142 m2 g−1 compared with that of the SnS2 granular aggregate sample (34 m2 g−1), presenting better cycling stability and rate capability.
Label‐free immunosensor based on interdigitated electrodes with Ni–Co nanowires
Authors: Siao Fu‐Yuan , Chang Yaw‐Jen , Shih Hung‐Ju 
Published: June 2018

This work presents a label‐free immunosensor consisting of interdigitated electrodes and Ni–Co nanowires (NWs) to determine the relative amount of analyte, using electroanalytical measurement. Interdigitated electrodes were fabricated by the conventional printed circuit board treatment and Ni–Co NWs were synthesised by the electrodeposition method using a porous anodic alumina oxide membrane as the template. The experimental results showed that Ni–Co NWs can provide specific binding with histidine‐tagged capture agent based on the method of immobilised metal affinity chromatography. Due to the large surface‐to‐volume ratio of NWs, this immunosensor had 2.6‐fold the immobilisation ability of flat Ni–Co film to absorb histidine‐tagged capture agent. Moreover, this immunosensor exhibited sensitivity in detecting low amounts of analyte. The electrical responses of the electroanalytical measurement of analyte, from 1000 to 625 ng/mL, could be discriminated; however, the fluorescence intensities became indiscriminative. This label‐free immunosensor has the potential to immobilise various capture agents through the use of histidine for different analyte analyses.
Height variation of the cutoff frequency in a sunspot umbra
Authors: Felipe T. , Kuckein C. , Thaler I. 
Published: June 2018

Context. In the solar atmosphere, the acoustic cutoff frequency is a local quantity that depends on atmospheric height. It separates low-frequency evanescent waves from high-frequency propagating waves.
Aims. We measure the cutoff frequency of slow magnetoacoustic waves at various heights of a sunspot umbra and compare the results with the estimations from several analytical formulae.
Methods. We analyzed the oscillations in the umbra of a sunspot belonging to active region NOAA 12662 observed in the 10 830 Å spectral region with the GREGOR Infrared Spectrograph and in the Fe I 5435 Å line with the GREGOR Fabry-Pérot Interferometer. Both instruments are attached to the GREGOR telescope at the Observatorio del Teide, Tenerife, Spain. We computed the phase and amplification spectra between the velocity measured from various pairs of lines that sample various heights of the solar atmosphere. The cutoff frequency and its height variation were estimated from the inspection of the spectra.
Results. At the deep umbral photosphere the cutoff frequency is around 5 mHz and it increases to 6 mHz at higher photospheric layers. At the chromosphere the cutoff is ~3.1 mHz. A comparison of the observationally determined cutoff with the theoretically predicted values reveals an agreement in the general trend and a reasonable match at the chromosphere, but also significant quantitative differences at the photosphere.
Conclusions. Our analyses show strong evidence of the variation of the cutoff frequency with height in a sunspot umbra, which is not fully accounted for by current analytical estimations. This result has implications for our understanding of wave propagation, the seismology of active regions, and the evaluation of heating mechanisms based on compressible waves.
Bleeding Symptoms in Carriers of Hemophilia A and B
Authors: Mauser Bunschoten E P , Houwelingen J C van , Sjamsoedin Visser E J M , Dijken P J van , Kok A J , Sixma J J 
Published: June 2018

SummaryIn order to investigate the bleeding tendency in clinically identified carriers of hemophilia, a self-administered questionnaire was held among 135 carriers of hemophilia A and B, 25 females with relatives with hemophilia and a matched group consisting of 60 females without relatives with hemophilia. Carriers of hemophilia appeared to suffer more often from bleeding than their relatives or the matched unrelated control group. A relation was seen between factor VIII :C or IX :C activity and the tendency to bleed. Obligatory carriers with normal factor VIII :C levels showed no bleeding tendency and were in this respect similar to a group of 25 females with relatives with hemophilia. This study shows that it is important to assay factor VIII: C or IX: C also in those women in whom the carrier status has already been established otherwise.
The Bleeding Time Is Inversely Related to Megakaryocyte Nuclear DNA Content and Size in Man
Authors: Kristensen S Dalby , Bath Philip M W , Martin John F 
Published: June 2018

SummaryThe relation between the bleeding time and the megakaryocyte nuclear DNA content and size was evaluated in eleven consecutive patients with normal steady state thrombopoiesis undergoing thoracotomy. A statistically significant inverse correlation was found between the bleeding time and both megakaryocyte DNA content (r = −0.71, p <0.05), megakaryocyte total size (r = ‒0.58, p <0.05), megakaryocyte cytoplasmic size (r = −0.64, p <0.05) and megakaryocyte nuclear size (r = −0.58, p <0.05). The megakaryocyte total size and the megakaryocyte cytoplasmic size were statistically significantly larger in men than women (p <0.02 and p <0.03 respectively). Changes in the megakaryocytes in the bone marrow are associated with changes in primary haemostasis in normal individuals.
Thrombin-Independent Activation of Platelet Factor XIII by Endogenous Platelet Acid Protease
Authors: Lynch Garry W , Pfueller Sharron L 
Published: June 2018

SummaryPlatelets contain factor XIII, an A subunit zymogen form of transglutaminase (TGase), that is activated by thrombin. In addition a thrombin-independent TGase (A#) was observed. A# was formed in platelet preparations lysed at acid pH, and its generation inhibited by protease inhibitors and alkaline pH. When maximal A# activity was generated in acidified lysates no further TGase activity could be induced by subsequent treatment with thrombin. Both FXIII zymogen and A# copurified as for F XIII, from either alkaline or from acidified platelet lysates respectively, by the conventional procedure. The pH optima, Km’s for NN dimethyl casein, molecular weights, heat lability of active forms, requirements for calcium and reducing agents, and immunological characteristics of both TGases were the same. Studies with inhibitor substrates suggested that a thrombin-like cathepsin C or carboxypeptidase was responsible for A# formation. Purified F XIII zymogen could be activated directly by cathepsin C. Thus, the predominant, and probably only, TGase of platelets is factor XIII, which may be activated either by thrombin or by endogenous platelet acid protease(s).
Effects of Ethanol on Pathways of Platelet Aggregation In Vitro
Authors: Rand Margaret L , Packham Marian A , Kinlough-Rathbone Raelene L , Mustard J Fraser 
Published: June 2018

SummaryEthanol, at physiologically tolerable concentrations, did not affect the primary phase of ADP-induced aggregation of human or rabbit platelets, which is not associated with the secretion of granule contents. Potentiation by epinephrine of the primary phase of ADP-induced aggregation of rabbit platelets was also not inhibited by ethanol. However, ethanol did inhibit the secondary phase of ADP-induced aggregation which occurs with human platelets in citrated platelet-rich plasma and is dependent on the formation of thromboxane A2. Inhibition by ethanol of thromboxane production by stimulated platelets is likely due to inhibition of the mobilization of arachidonic acid from membrane phospholipids, as ethanol had little or no effect on aggregation and secretion induced by arachidonic acid or the thromboxane mimetic U46619. Rabbit platelet aggregation and secretion in response to low concentrations of collagen, thrombin, or PAF were inhibited by ethanol. Inhibition of the effects of thrombin and PAF was also observed with aspirin-treated platelets. Thus, in addition to inhibiting the mobilization of arachidonate for thromboxane formation that occurs with most agonists, ethanol can also inhibit aggregation and secretion through other effects on platelet responses.
Plasminogen Activator Inhibitor Activity in Bacterial Infection
Authors: Páramo J A , Fernández Diaz F J , Rocha E 
Published: June 2018

SummaryIt has been experimentally shown that endotoxin induces a marked increase in the levels of a fast-acting inhibitor of plasminogen activator (PAI). The plasma PAI activity and tissuetype plasminogen activator (t-PA) concentrations were measured in 61 patients with human septicaemia and results were compared with those observed in healthy controls. There was a markedly significant increase of PAI in plasma and platelet extracts of patients with septicaemia as compared to controls (p <0.0001). No correlation between PAI and endotoxin concentration was observed. Fibrin autography of plasma samples confirmed that activator inhibition was associated with the formation of an enzyme-inhibitor complex. t-PA activity was similar in patients and controls, whereas t-PA Ag showed a significant increase in patients (p <0.0001). A significant inverse correlation between t-PA activity and PAI was observed (p <0.05). PAI activity was higher in patients with positive blood cultures (p <0.0001) and gram-negative septicaemia (p <0.0001). There was also a significant increase of PAI levels in patients with disseminated intravascular coagulation (DIC) as compared with patients without DIC (p <0.001). We conclude that there is a marked increase of PAI in patients with sepsis. Increased PAI activity may contribute to the pathogenesis of DIC associated with septicaemia.
Effects of Reagent and Instrument on Prothrombin Times, Activated Partial Thromboplastin Times and Patient/Control Ratios
Authors: Naghibi Freshteh , Han Yangsook , Dodds W Jean , Lawrence Charles E 
Published: June 2018

SummaryActivated partial thromboplastin times accumulated from two proficiency testing surveys were analyzed to determine simultaneously the effects of the method and reagent used. Prothrombin time results were reevaluated concomitantly for comparison.A robust two-way analysis of variance was applied to determine the effect of method and reagent on APTT results. The effect of the reagent and method on the ratio of abnormal to normal plasma clotting times was determined. We found a substantial difference in ratios for the PT using different reagents on the same instrument. There was an even larger effect of reagents on APTT ratios.Our finding of substantial reagent effects for the PT and APTT clearly support the need for standardization. We found standardization to be feasible only for the PT, and only if applied in a form consistent with the inherent error structure of the data. For the APTT the present methodology and plasma samples did not achieve consistent standardization.
Serial Determinations of PF4 and βTG: Comparisons Between Multiple Venipunctures vs a Catheter Infusion System
Authors: Strauss William , Cella Guiseppe , Myers Charles , Sasahara Arthur A 
Published: June 2018

SummaryPlatelet factor 4 (PF4) and beta thromboglobulin (βTG) are platelet-specific proteins which are released upon platelet aggregation and which can be accurately measured by radioimmunoassay. We devised a catheter-infusion system that enables serial determinations of these proteins.In 20 subjects (10 healthy volunteers and 10 patients with stable coronary artery disease), we compared samples collected by individual venipunctures with those simultaneously obtained by means of a simple catheter-infusion system. At least 5 samples were obtained over a period of time which was as long as 60 min, and at least 30 min. Subjects with stable coronary artery disease were selected so that they would be expected to have stable and normal PF4 and βTG levels. Thus, elevations of either PF4 or βTG would represent artifacts secondary to sampling technique.Analysis of the results demonstrated that the catheter-infusion system was equivalent to individual venipunctures for determination of PF4 and βTG . 16.8% of samples obtained via the catheter and 17.2% of those obtained by individual venipunctures were spuriously elevated.A second series of studies were performed to refine the technique further by examining the impact of infusion rate and the addition of citrate phosphate dextrose (CPD) to the infusate. Ten additional subjects had catheter systems utilized in both arms simultaneously. The addition of CPD resulted in significantly less abnormal values at slower infusion rates (1 and 2.5 cc/min). At 5 cc/min D5/w or saline alone are suitable.These investigations confirm that this simple catheter system is equivalent to individual venipunctures for determination of PF4 and βTG while avoiding patient discomfort. Also noted was the fact that a high percentage of determinations could be spuriously elevated by either technique under clinical demands. Thus, multiple determinations from the same subject are necessary to assure reproducibility.
Elasticity of Fibrin and Protofibrin Gels ls Differentially Modulated by Calcium and Zinc
Authors: Marx Gerard 
Published: June 2018

SummaryThe mechanical properties of fibrin and protofibrin gels in the presence of physiologic levels of Ca(II) and Zn(II) are described. As monitored with a thrombelastograph, Ca(II) (0.5–2 mM) increases the rate of development and the maximum level of gel elastic modulus (G) of fibrin and protofibrin gels. Zn(II) (10–50 μM) decreases the elastic modulus of those gels, even in the presence of a large excess of Ca(II). This contrasts with the ability of both divalent cations to increase fibrin and protofibrin gel turbidity. Unlike the turbidity or fibre thickness of fibrin and protofibrin gels, both of which are increased by these cations, gel elasticity is increased by Ca(II) but decreased by Zn(II). h is demonstrated that Ca(II) and Zn(II) modulate fibrin and protofibrin gels independently of one another, and that they have opposing effects on the mechanical properties of the gels. The disparity between the visual (turbidity, TEM) and the mechanical (elasticity) properties of (proto)fibrin gels indicates the need for new conceptual and analytic paradigms.
Resolution and Reconstitution of Interplatelet Recognition During Aggregation
Authors: Agam Galila , Livne Avinoam 
Published: June 2018

SummaryIn previous studies it was shown that fixed platelets bearing covalently-bound fibrinogen participate passively in release-related aggregation, and that thrombospondin is the released compound which specifically and selectively recognizes the affixed fibrinogen. The present study demonstrates that the phenomenon of passive participation is also obtained with fixed platelets bearing covalently-bound thrombospondin. Moreover, a full resolution and reconstitution of interplatelet recognition during aggregation was obtained with two different systems: (a) fixed platelets bearing affixed fibrinogen were caused to aggregate when stirred and supplemented with soluble thrombospondin; (b) fixed platelets bearing fibrinogen and fixed platelets bearing thrombospondin, each uncapable of undergoing aggregation, aggregated when combined and stirred. It is concluded that fibrinogen and thrombospondin play a major role in the molecular mechanism of interplatelet recognition during aggregation.
Tissue Plasminogen Activator in Human Megakaryocytes and Platelets: Immunocytochemical Localization, Immunoblotting and Zymographic Analysis
Authors: Jeanneau C , Sultan Y 
Published: June 2018

SummaryTwo approaches were used to identify and characterize the presence of tissue plasminogen activator (t-PA) in megakaryocytes and platelets. We investigated the fibrinolytic activity of human megakaryocytes (MK) and platelets. The presence of t-PA antigen in megakaryocytes and platelets was demonstrated using immunocytochemical techniques and polyclonal or monoclonal antibodies specific for t-PA. When cells were applied to fibrin plates, lysis zones developed around isolated human megakaryocytes, whereas no fibrinolytic activity appeared when either intact washed platelets or platelet lysate were deposited. After SDS-PAGE of platelet and MK extracts (Triton X-100) immunoblotting and peroxidase staining identified t-PA antigen in several bands. Zymographic analysis of SDS-PAGE carried out on fibrin film overlays identified one or two zones corresponding to free or complexed t-PA. These results indicate that t-PA is present in platelets as well as in the precursor cells, however, in platelets, t-PA may not be immediately available for plasminogen activation and fibrin degradation. From our findings and from previous work of others, it appears that platelets may either activate or inhibit the fibrinolytic system. Therefore the conditions of plasminogen activation by platelet t-PA and plasmin inhibition by platelet α2-antiplasmin or other inhibitors have to be precised before the role of platelets in clot dissolution is understood.The physiological role of platelets in fibrinolysis and clot dissolution remains unclear. In 1953, the antifibrinolytic activity of blood platelets was demonstrated (1) and in the early 1960’s a fibrinolytic activity, increasing with platelet concentration in the experimental system, was shown (2, 3). In 1979, it was demonstrated that metabolically active platelets were necessary for platelets to play a role in the fibrinolytic system (4). More recently it was established by Plow and Collen (5) that the specific plasmin inhibitor, α2-antiplasmin is a constituent of platelet α-granules.In the present study, we investigated the fibrinolytic components and activity of human megakaryocytes and platelets, using zymographic and immunochemical techniques. We report here our observations that human megakaryocytes and platelets contain tissue plasminogen (t-PA) which possesses fibrinolytic activity.
Fibrinolysis by Bile
Authors: King Burnham J. 
Published: June 2018

SummaryFibrinolytic activity is described in the bile of man and of several species of mammal. This activity can be precipitated from whole bile by ammonium sulphate, by acetone, and by a chlor of orm/methanol partition technique. It behaves as an anion at pH 7.4. Ammonium sulphate precipitated bile is caseinolytic, and fibrinolytic on a heated fibrin plate. It gives a peak of fibrinolytic activity on column chromatography with sephadex G50 at Kav = 0.3, suggesting a molecular weight of ± 15,000.
Use of the Megathrombocyte to Demonstrate Thrombopoietin
Authors: Marc Weiner , Simon Karpatkin 
Published: June 2018

SummaryQuantitation of megathrombocyte (large platelet) number was used as an assay for the detection of a humorally-transmitted thrombopoietic stimulus, thrombopoietin. Donor guinea pigs were depleted of circulating platelets by the injection of rabbit anti-guinea pig platelet antibody. Plasma from these donor guinea pigs, when injected into recipient guinea pigs raised their platelet count 1.5 fold and their megathrombocyte number 2.7 fold when compared to plasma injected from donor guinea pigs with normal platelet counts. A lag period of 4 to 5 days preceded the rise in platelet count and megathrombocyte number.
Cold Promoted Activation of Factor VII
Authors: Gjønniess H 
Published: June 2018

SummarySeveral known activators of the plasma kallikrein system were tested for the ability to induce cold promoted activation of factor VII.All the prekallikrein activators tested (EACA, trypsin, acetone, urokinase, kaolin, Liquoid, ellagic acid) revealed generation of factor VII activator activity (CPA). Simultaneously the plasma kallikrein system was activated. A good correlation was demonstrated between the factor VII activation and the kallikrein activity.Glandular kallikrein, bradykinin, or kallidin revealed no effect on the coagulation system. Thus, the correlation between the factor VII activation and the kallikrein system seemed to be restricted to plasma kallikrein.
Cold Promoted Activation of Factor VII
Authors: Gjønnæss H 
Published: June 2018

SummaryThe cold promoted shortening of the thrombotest times induced by incubation of plasma with prekallikrein activators for 20 hours at 0° C is due to activation of factor VII. No change was recorded for the other coagulation factors. The activation was strong, as the presence of 1 per cent cold activated factor VII reduced the thrombotest time of factor VII deficient plasma from 115 to 38.7 seconds.The activation of factor X by the cold activated factor VII occurred in the course of seconds, in the presence of calcium and thromboplastin. Cold promoted activation of factor VII also implied reduced cephalin time, probably via traces of thrombin inducing intrinsic factor X activator activity during the clotting test.Generation of cold promoted activator activity (CPA) was independent of coagulation factors V, VIII, IX, X, XI, and calcium, but factor XII was a prerequisite. Of factor VII even traces were sufficient for the generation of CPA. The activation of the kallikrein system, that occurs in parallel with the cold promoted activation of factor VII, occurred both in factor VII deficient plasma and in ordinary control plasma. In the reaction sequence, the activation of factor VII therefore is less likely to be the first step, it possibly is a result of activation of the kallikrein system.