bluuebunny/crossref_metadata_2025 huggingface dataset:
Phospholipid Composition And Phospholipid-Modifying And Prostaglandin-Synthesising Enzymes In Human Platelet Surface And Intracellular Membranes Isolated By Free Flow Electrophoresis
Authors: Crawford N , Lagarde M , Menashi S , Carey F
Published: July 2018

A mixed membrane fraction prepared from human platelets which have been exposed to neuraminidase and surface labelled with 125I–Lens culinaris separates into three vesicle subpopulations in a high voltage free flow electrophoresis chamber [Bender Hobein/MSE]. One fraction [NI] which is devoid of the lectin label has exclusive localisation of NADH cytochrome–c–reductase activity with high enrichment [l2-14 fold]. The two less electronegative fractions [NII and NIII] account for the whole of the lectin label and have adenylate cyclase activity. Fraction NI which is believed to be of intracellular origin has a low cholesterol/phospholipid ratio [0.291 ± 0.014], negligible sphingomyelin and has a high fluidity as measured by fluorescence polarisation using diphenyl hexatriene. Fractions NII and NIII, believed to represent two different surface membrane domains, have high cholesterol/phospholipid ratios [0.606 ± 0.027 and 0.739 ± 0.054] are rich in sphingomyelin and have significantly higher microviscosities than NI . The polypeptide profile of NI is also particularly distinctive. Using 2[l-14C] arachidonyl phosphatidyl choline and 2[l-14C] arachidonyl diacyl-glycerol as substrates, phospholipase-A2 and diglyceride lipase activities have been measured in the three membrane fractions. Both enzymes are almost exclusively located in the intracellular membrane fraction NI with high enrichment ratios with respect to homogenate activities. Similarly cyclooxygenase and thromboxane synthetase activities are also largely confined to the intra-cellular membranes. Full analytical data for the phospholipid and fatty acid compositions of the surface and intracellular membrane fractions will also be presented.
The Inhibition Of Tissue Activator And Urokinase By Human Plasma
Authors: Walker J E , Ogston D
Published: July 2018

The activity of urokinase (UK) on fibrin plates was inhibited by dilutions of normal plasma which failed to inhibit porcine heart activator (TA). Following passage of plasma through lysine-Sepharose inhibition was readily detected.

Normal plasma separated on DEAE-Sepharose or, after passage through lysine-Sepharose, on Sephadex G-100 provided fractions in three regions capable of inhibiting the activity of TA.

The high molecular weight fractions inhibited both TA and UK. When plasma was fractionated on Sepharose 4B the inhibitory activities against UK and TA eluted separately. UK inhibition appeared in the fractions containing α2 macroglobulin; the inhibitor of TA was present in fractions of higher molecular weight.

Activator inhibition was found in two lower molecular weight regions of plasminogen-free plasma separated on Sephadex G-100: one region inhibited TA and coincided with the peak antiplasmin activity assessed by a chromogenic substrate. The other region comprised fractions which inhibited both TA and UK. Alpha1- antitrypsin and antithrombin III eluted after both inhibitory regions.

It is concluded that normal plasma contains at least three proteins with inhibitory activity against TA and two which inhibit UK; one of these is capable of inhibiting both activators.
Substrate Specificity Of The Coagulant Enzymes From The Venom Of Vipera Russellii Russellii And Vipera Russellii Siamensis
Authors: Lavine Kathrine Kovach , Jackson Craig M
Published: July 2018

Two enzymes that increase the rate of coagulation, are present in the venom of Vipera russellii and have been widely used as tools in investigating coagulation. Venoms from two subspecies of Vipera russellii are available, but the differences between these subspecies has not previously been investigated. The substrate specificities of these two enzymes and possible differences between the same enzyme from the two subspecies of Russell’s viper have not been extensively characterized. The “Factor X activator” activates not only Factor X, but Factor IX and Protein C. The relative rates of activation of these zymogens have been investigated by both their chromogenic substrate hydrolase activity and sodium dodecyl sulfate gel electrophoresis and have been observed to be markedly different. Factor X is activated far more rapidly than either Protein C or Factor IX. The “Factor X activator” from V. r. russellii and V. r. siamensis differ in their activities on these zymogens as well. Elimination of the region of the light chain of Factor X that contains the gamma carboxyglutamic acid residues also markedly reduces the rate at which it can be activated.

The “Factor V activator”, which mimics thrombin in activating Factor V, appears to be much more specific. Little or no difference in the rate of Factor V activation by the enzymes from the two subspecies has been observed. Most importantly, the “Factor V activator” does not activate Protein C, making it a particularly useful tool for investigation of Factor V when the effects of Factor V degradation by activated Protein C are to be avoided.
Detection Of High Affinity Fibrinogen Binding Sites On Human Platelets Stimulated By ADP: Comparison Of Two Methods Of Platelet Separation
Authors: Niewiarowski Stefan , Morinelli Thomas A , Kornecki Elizabeth
Published: July 2018

Binding of fibrinogen to specific receptors on human platelets exposed by ADP results in platelet aggregation. There are controversial data regarding classes and number of fibrinogen receptors, the values range from one to two classes and 1,000-80,000 receptors per platelet as reported in the literature. We have studied the interaction of fibrinogen with a) platelets washed by differential centrifugation according to Mustard and colleagues (washed platelets - WP) and with b) gel-filtered platelets (GFP). Platelet aggregation was studied with 100 μM ADP and with various concentration of fibrinogen. Maximal velocities of aggregation for WP and GFP were 81 and 47 units per min, respectively, and the Km values for fibrinogen calculated from the rate of aggregation were 0.9 × 10-7M for WP and 5.8 × 10-7M for GFP. The level of platelet fibrinogen released into the suspension from WP and GFP amounted to 2.4 μg and 15.0 μg per 10 9 platelets/ml, respectively, as measured by the staphylococcal clumping test. Analysis of 125I-fibrinogen binding data by the method of Scatchard and Feldman revealed 1,300 high affinity receptors (KD 3.2 × 10-8M) and 80,000 low affinity receptors (KD 5.6 × 10-5M) for WP. The binding of 125I-fibrinogen to GFP was greatly diminished. The number of fibrinogen receptors exposed by ADP on GFP and their binding affinity are under investigation in our laboratory. In conclusion, GFP were less sensitive to fibrinogen than were WP as shown in the aggregation and 125I-fibrinogen binding studies. It appears that the method of platelet separation is critical for the assessment of fibrinogen binding. Platelet activation and release of intact platelet fibrinogen during gel-filtration may interfere with the detection of high affinity fibrinogen binding sites.
Detection Of Antiplatelet Antibodies In Bstients With Idiopathic Thrombocytopenia Purpura (ITP) And In Patients With Rubella And Herpes Group Viral Infections
Authors: Kahane S , Dvilansky A , Estock L , Nathan I , Zolotov Z , Sorov I
Published: July 2018

A highly sensitive enzyme linked immunosorbent assay (ELISA) technique was developed for serological detection of antibodies against platelets. Protein A covalently bound to Sepharose CL-4B was used to enrich sera in the IgG3 subclass. The assay uti lized antigen-coated polystyrene microplates; antigen consisted of sonicated platelets obtained from 0, Rh negative donors. Goat anti-human IgG peroxidase conjugate was used to detect antigen bound antiplatelet antibodies. The ELISA procedure was applied to detect antiplatelet antibodies in patients with herpes or rubella viral infections and in patients with idiopathic thrombocytopenic purpura (ITP). Twenty-eight sera from 13 thrombocytopenic patients showed high levels of antiplatelet antibodies. Two splenectomized patients in remission became negative for antiplatelet antibodies.

Seventy-four sera from patients with serological diagnosis of herpes group viral infections comprising 10 cases of cytomegalovirus, 9 cases of varicella, 6 cases of herpes simplex and 4 cases of Epste in-Barr virus were examined for the presence of antiplatelet antibodies. All ten patients with acute CMV infection presented high titers against platelets. In four of them the highest titer of antiplatelet antibodies was observed even when the specific anti-CMV titer was still very low. All six patients with herpes simplex and all four cases with EBV as well as seven out of nine patients with varicella showed positive titers of antiplatelet antibodies. Out of eight cases of rubella which were also examined seven displayed antibodies against platelets. Sera from a group of 51 healthy controls were evaluated for antiplatelet antibodies. Forty-nine (96%) were negative ( 40), whereas the other two were only slightly positive.
Normalization By Suloctidil Of Decreased Platelet Survival In Patients With Heart Prosthetic Valves In Randomized Controlled Double Blind Trial
Authors: Ciavarella N , Antoneecchit S , D’Elia N , Ranieri P , Manzini A
Published: July 2018

Platelets play an important role in thromboembo lie episodes in the life of patients with heart prosthetic valves. Decreased platelet survival and increased B-Tromboglobulin and Platelet F4 in the blood are constant features of such condition.

45 patients on long term anticoagulant treatment (thrombotest 5-10%),26 males(mean age 46) and 19 females(mean age 44), were studied. 22 normal sub jects served as controls.

Platelets survival was studied with MDA production after 5oo mg Aspirin intake and was found signifi canly reduced in patients in comparison to contro Is(p.8.00±1.4 days;c.10.00±1.67 days; P<0.01).

BTG and PF4 as measured by RIA were increased (BTG:p.97.8±59 NG/ML;c.29.18±22.40 NG/ML; P<0.01) (PF4:p.36.6±26.5 NG/ML;c.6.29±4.78 NG/ML; P<0.01) The patients were randomly allocated to one of the following groups( 15 subjects each): placebo, Suloctidil 600 mg:die, Suloctidil 1200 mg:die. Duration treatment was 30 days.

The effect of Suloctidil was significantly different from that of placebo( P<0.005),as regards Platelet survival without difference between dosa ges of the drug;as concerns BTG and PF4 the chang es under placebo and drug were not different.
Kinetics Of Malondialdehyde Formation Induced By Arachidonic Acid In Platelets Of Rats With High Glutathione Peroxidase Activity (Selenium Treatment)
Authors: Doni M G , Bonaccorso G
Published: July 2018

We studied some kinetic aspects of malondialdehyde (MDA) production stimulated by Arachidonic acid (AA) in platelets of rats with a high Glutathione Peroxidase (GSH-Px) activity. The increase in enzyme activity was obtained by oral intake of Se (0.3ppm sodium selenite) to animals for 30 and 80 days (Groups 1 and 2), as the element is part of the enzyme molecule and its administration enhances GSH-Px activity. GSH-Px protects the biological membranes from damage induced by lipid hydroperoxides; moreover, it intervenes in the AA cascade because it converts the endoperoxide PGG2 into PGH2. On the basis of our findings it may be assumed that GSH-Px is the regulatory step of the overall process of transforming AA into MDA. In fact the treatment with Se induces 100% enhancement in GSH-Px activity (Paglia and Valentine’s method) and 54% increase in MDA formation (thiobarbiturate method). Se treatment produced a decrease in the apparent Km values with respect to AA, presumably indicating an increased affinity of GSH-Px towards the substrate. However, the platelets of treated rats showed decreased Vmax. It is concluded that the increased MDA production caused by Se treatment is prevailingly due to activation of GSH-Px rather than to enhancement of the enzyme synthesis, even if both mechanisms may play a role in the phenomenon.
Preparation Of Factor IX-Deficient Human Plasma Using RFF-IX/1 Monoclonal Antibody
Authors: Rotblat F , Goodall A H , Janossy G , Kemble G , O’Brien D P , Rawlings E , Russell G , Tuddenham E G D
Published: July 2018

A cell line that secretes a monoclonal antibody to factor IX has been produced by fusing spleen cells from a mouse that had been hyper immunised to purified factor IX with mouse myeloma cells (line P3-NSI/I-Ag4-1). Hybrid cells were selected and a monoclonal cell line has been established in culture. This cell line secretes an IgGl(k) antibody (RFF-IX/1) with high affinity for a site related to the coagulant function of factor IX.

Monoclonal antibody was partially purified from ascitic fluid from mice implanted with the RFF-IX/1 secreting cells by precipitation at 50% saturation with ammonium sulphate. This fraction has typically 630 NIH units/ml anti IX activity and 13.5 mg/ml protein. It was coupled to cyanogen bromide activated Sepharose 2B in the ratio of 9 mg. protein/1 ml gel. A column containing 10 ml of this gel removed all the assayable factor IX from the first 280 ml of normal ci.trated plasma that was passed over it. After that volume small amounts of factor IX could be detected in the effluent. Subsequently 10-20% of the factor IX activity adsorbed could be recovered by eluting the column with 3 M potassium iodide.

Immuno-affinity depleted plasma could be used as substrate in a one-stage factor IX assay under routine laboratory conditions and was undistinguishable for that purpose from severe Christmas disease plasma.
The Pre-Gelation Phase Of Fibrin Aggregation
Authors: Wiltzius P , Dietler G , Känzig W , Haeberli A , Hofmann V , Straub P W
Published: July 2018

So far, fibrin aggregation in solution has been studied by either static or dynamic light scattering and the data analyzed using a linear chain model. In the present study we have combined static and dynamic light scattering and compared the data with a model predicting a sol-gel transition. Fibrinogen solutions (cone. 2 mg/ml, Tris-NaCl buffer 0.15 M, pH 7.4) were incubated at 20°C with small amounts of Reptilase or thrombin, extending the polymerization process to 4-6 hours. The scattered intensity and correlation function were recorded for scattering angles 30° ≤ θ ≤ 150°. The measured data were compared with model calculations based on the Flory-Stockmayer distribution which predicts a sol-gel phase transition. This distribution is determined by a parameter λ indicating the extent of aggregation, λ = 0 corresponding to the monomeric solution and λ = 1 indicating sol-gel transition. Good agreement could be found for 75 nm long monomeric units aggregating: a) end-to-end for the beginning of the aggregation (0 0.3) and b) in a staggered overlap pattern as proposed by Ferry for the progressing polymerization (0.3 ≤ λ < 1). Prior to the gel point (λ = 1) no systematic difference was observed between the data obtained after activation with thrombin which splits both peptides A and B from fibrinogen and Reptilase which exclusively liberates fibrinopeptide A. This confirms that the release of fibrinopeptide A is the essential prerequisite for the aggregation process.
Influence Of Fibrin Clots On The Development Of Granulation Tissue In Preformed Cavities
Authors: Hedelin H , Johansson S , Peterson H I , Teger-Nilsson A C , Pettersson S
Published: July 2018

We have recently presented a new technique for occlusion of long standing fistulae by excochleation and plugging with a fibrin clot (Lancet, 1979). The intention with the technique was to keep the fistulous tract dry and occluded by a species-specific substance until healing had occurred. To study the importance of the fibrin clot in the present context an experimental study in rats has been performed. Perforated Teflon cylinders were implanted subcutaneously, removed after 1, 2 and 4 weeks and subjected to macro-and microscopic examination. Comparison was made between empty cylinders and cylinders filled with a fibrin clot.

The examination after one week revealed the initially fibrin clot filled cylinders still to be filled by the clot. Ingrowth of granulation tissue through the cylinder perforations had started. The initially empty cylinders were still empty. At the 2-week examination the initially fibrin clot filled cylinders were at the peripheral half filled by ingrowing granulation tissue, the central half was filled by the implanted fibrin clot. The initially empty cylinders were filled to a lesser degree by ingrowing granulation tissue and a loose exdogenous clot centrally.

The 4-week examination revealed both the initially empty and the initially fibrin clot filled cylinders to be completely filled up by granulation tissue of varying organisation.

During the time it takes for the granulation tissue to grow into the cylinder the clot remains intact centrally and together they keep the cylinder filled up. It furthermore appears as if the fibrin clot induces a more rapid ingrowth into the cylinder. Both observations confirms the importance of the clot for the fistula occlusion.
Fibrinogen Consumption In Breast Cancer And Its Relation To The Extent And Type Of Metastases
Authors: Pengo V , Cartei G , Casara D , Guerra C , Bertaglia E , Zanella R , Bajo M , Belmonte P
Published: July 2018

A subclinical intravascular coagulation-fibrinolysis syndrome (I.C.F.), is commonly present in cancer patients: a shortened fibrinogen halflife, in fact, have been found in most patients with malignancies, not considering, however, the type and extent of disease. 28 breast cancer patients, without bleeding and thromboembolic disorders and not receiving chemo-radiotherapy, have been assessed for the presence of I.C.F. syndrome by mean of radiofibrinogen half-life, fibrinogen level, ethanol gelation test, fibri- nogen/fibrin degradation products (FDP). 16 patients without metastases were studied before surgery, while 12 patients with metastases were studied after more than one month from the operation (7 diffuse metastases, 5 pulmonar metastases). 14 out of 16 patients of the first group, and 6 out of 7 with diffuse metastases showed a markedly shortened fibrinogen half-life (hours) (x=53.9±18.2, x=54.2±16.4 as mean±SD respectively), while all the patients with pulmonar metastases showed a normal fibrinogen half-life (x=84±9.9). Normal range was 73-91 h. FDP were almost always normal. In conclusion the tumor per se determine a fibrinogen consumption without a competent fibrinolysis. Pulmonar metastases don’t promote fibrinogen consumption and/or they don’t need fibrin for their growth and spread,
Effect Of Radiologic Contrast Agents On Laboratory Parameters Used In The Evaluation Of Hemostatic Function
Authors: Parvez Z , Fareed J , Moncada R , Agrawal P , Messmore H L
Published: July 2018

Coagulation disorders of the intrinsic and extrinsic pathways are monitored by measuring such clotting times as partial thromboplastin time (PTT), prothrombin time (PT), and thrombin time (TT). These laboratory tests reflect the congenital and acquired deficiencies of clotting factors and are used for controlling anticoagulant therapy. We have previously reported that meglumine (cation) in radiologic contrast media (CM) inhibits factor VIII, IX, and thrombin (Fed. Proc. 36 (3), 317, 1977) and consequently prolonges clotting times. The effects of ionic and nonionic CM on pathological plasma were investigated by employing routine clotting assays. Patient plasmas showing PT values >15 secs., were mixed with Renografin-60 (Squibb and Sons, Princeton, New Jersey), P-297, iothalamic acid, and ioxigalic acid (Laboratoire Guerbet, Paris, France) and PTs were then determined. Renografin-60 (30 mg/ml), iothalamic acid (10 mg/ml) and ioxigalic acid (10 mg/ml) produced an increase in the PT values by 60-80% base levels, whereas no such effect was seen with P-297. In normal plasma (NHP), the PT values were elevated only by 5-10%. In another study, patient plasmas showing PTT > 40 secs., were supplemented with CM and the mixtures were assayed for PTT. Except with P-297 there was a 50-60% increase in PTT due to the interactions of ionic CM. Our studies show that during anticoagulant therapy, if clotting assays are performed immediately after radiologic diagnostic procedures, utilizing intravascular contrast agents, erroneous conclusions can be drawn. Our studies have also shown that certain ionic CM can produce transient effects on coagulation parameters and therefore, due consideration be given to the presence of these agents in patients suffering from platelet function defects and other coagulation disorders.
Evidence For The Appearance Of Two Different Sets Of Polymerization Sites Upon The Sequential Release Of Fpa And Fpb
Authors: Brosstad F , Kierulf P
Published: July 2018

Human des-AA (fmA) and des-AABB (fmAB) fibrin monomers were prepared from fibrinogen (F) exposed to insol. rep- tilase or thrombin in 2.5M urea, pH 7.4, for lh. FPA-RIA and N-term. amino acid anal, confirmed full conversion to fm species as above. Solubility of fmA and fmAB ( ) was determined by stepwise addition under whirlmixing to: I. Citrated plasma=10% (7.5%). II. BaSO4-adsorbed, recalcified plasma=3% (2.5%). III. F in 0.15 M Tris pH 7.4=17% (13%). Labeled fmA and fmAB incubated with FSF (preactivated with insol. thrombin) disclosed lower rates of gamma-gamma dimer formation and especially alphapolymer formation in fmA-clots than in fmAB clots. Affinity towards fibrinogen-Sepharose was definitely lower with fmA compared to fmAB when existing in soluble form in plasma. Increasing amounts of F progressively retarded and finally inhibited the polymerization of fmA and fmAB, and the retardation was linearly proportional to the F/fm ratio. The polymerization of fmA at a given F/fm ratio was more retarded than was that of fmAB. Ultracentrifugation (Airfug, Beckmann) of BaSO4-adsorbed, recalcified plasma containing I125f and T131 fmA or fmAB suggests complex formation between F and fm. Similar experiments with EDTA-plasma disclosed no fmA-F complex formation, whilst fmAB-F complexes still could be traced.

From the above experiments it is concluded that two different sets of polymerization domains are exposed during the sequential release of FPA and FPB. Since fmAB solubility is far less than twice that of fmA, and the amount of F required to inhibit fmAB polymerization is far less than twice the amount of F necessary for inhibition of fmA polymerization, it is concluded that the polymerization domains exposed upon FPB release are less avid than the corresponding domains exposed upon FPA release.
Protein S mRNA in Patients with Protein S Deficiency
Authors: Sacchi E , Pinotti M , Marchetti G , Merati G , Tagliabue L , Mannucci P M , Bernardi F
Published: July 2018

A protein S gene polymorphism, detectable by restriction analysis (BstXI) of amplified exonic sequences (exon 15), was studied in seven Italian families with protein S deficiency. In the 17 individuals heterozygous for the polymorphism the study was extended to platelet mRNA through reverse transcription, amplification and densitometric analysis. mRNA produced by the putative defective protein S genes was absent in three families and reduced to a different extent (as expressed by altered allelic ratios) in four families. The allelic ratios helped to distinguish total protein S deficiency (type I) from free protein S deficiency (type IIa) in families with equivocal phenotypes. This study indicates that the study of platelet mRNA, in association with phenotypic analysis based upon protein S assays in plasma, helps to classify patients with protein S deficiency.
Some Observations on the Coagulation Defect During Treatment with the Anticoagulant “Sintrom”
Authors: Vermeulen H. J , ten Bokkel Huinink S. A , Radhakishun K. S
Published: July 2018

Conclusions

1. The decrease of activity of prothrombin, occuring during administration of “Sintrom”, becomes only manifest when the activity of “factor VII” has fallen to less than half its normal value.

2. The behaviour of the thrombin time is the manifestation of an important difference between the coagulation defect in hepatitis and that on administration of Sintrom.
Regulation, Location and Activity of Plasminogen Activator Inhibitor 2 (PAI-2) in Peripheral Blood Monocytes, Macrophages and Foam Cells
Authors: Ritchie Helen , Jamieson Alec , Booth Nuala A
Published: July 2018

Monocytes, macrophages and foam cells are central to atherogenesis. We have examined the potential ability of monocytes, macrophages and foam cells to affect the stability of deposited fibrin, characteristic of the atherosclerotic plaque, by their production of plasminogen activators and their inhibitors. Monocytes respond to thrombin and LPS by up-regulation of PAI-2 synthesis, and PAI-2 is their major product among the plasminogen activators/inhibitors. In contrast, macrophages and foam cells, while they did produce PAI-2, did not respond to thrombin and LPS by an increase in its synthesis. All PAI-2 produced by macrophages and foam cells was accumulated intracellularly, whereas monocytes also secreted PAI-2. Secreted PAI-2 was active as an inhibitor of u-PA, whereas intracellular PAI-2 required detergent treatment to generate activity. Thus monocytes, but not macrophages or foam cells, produce and secrete active PAI-2, thus potentially affecting fibrin stability in the local environment.
Impact of Crystalloid or Albumin Priming of the Heart–Lung Machine on Inhospital Outcome after Coronary Artery Bypass Surgery
Authors: Weiler Pia , Hamiko Marwan , Mellert Fritz , Roell Wilhelm , Roell Martina , Welz Cecilia , Duerr Georg Daniel
Published: July 2018

Background Crystalloid priming is a cost-effective, free from immunological reactions, and independent from human plasma delivery. However, there is some debate on the negative impact of low plasma colloid pressure and higher incidence of systemic inflammatory response syndrome (SIRS). The aim of the study was to rule out any adverse effects of crystalloid priming on the postoperative outcome.

Methods We investigated 520 consecutive patients, including emergencies, who had isolated on-pump coronary artery bypass grafting in 2009 by retrospective analysis in our clinic. Crystalloid priming (n = 294) was introduced as an alternative to albumin (n = 226). Reviewing patient charts and IT-based data generated a dataset of perioperative parameters.

Results There were no differences with respect to demographical data and preexisting comorbidities between both groups. Despite equal perfusion times, more volume had to be substituted during extracorporeal circulation following crystalloid priming. However, this did not influence the inhospital outcomes. According to the definition of the “Sepsis-3 Guidelines,” the incidence of SIRS was similar. There was no difference in the need for a vasopressor treatment, and only transient higher serum lactate levels were found in the crystalloid group. The incidence of neurologic and organ-related adverse events, as well as 30-day mortality was comparable.

Conclusion The use of crystalloid priming is safe in coronary artery bypass grafting surgery in adults. However, there might be a greater need for crystalloid fluids during surgery.
Group classification of a class of generalized nonlinear Kolmogorov equations and exact solutions
Authors: Rassokha I. , Serov M. , Spichak S. , Stogniy V.
Published: July 2018

A class of generalized nonlinear Kolmogorov equations is investigated. We present the group classification of Lie symmetries of the class with respect to the group of equivalence transformations. We find a number of exact solutions of nonlinear Kolmogorov equations which have the maximal symmetry properties.
Langevin equation for coulomb collision in non-Maxwellian plasmas
Authors: Oumbarek Espinos Driss , Zhidkov Alexei , Kodama Ryousuke
Published: July 2018

The Langevin equation method is developed for the simulation of elastic collisions in non-Maxwellian plasmas by particle methods. The properties of random processes are shown to allow splitting not only of collisions between different compounds but even splitting inside a compound. The latter drastically simplifies extension of the method for colliding plasmas. The method is also verified by obtaining characteristics of runaway electron generation under an external electric field and under an external magnetic field.
Improved photomultiplication in inverted-structure organic photodetectors via interfacial engineering
Authors: Tang Feng , Wang Cheng , Chen Qi , Lai Junqi , Wang Wenbin , Zhang Fujun , Chen Liwei
Published: July 2018

Organic photodetectors with photomultiplication, i.e., ultrahigh gain, have drawn extensive attention. Here, we report poly(3-hexylthiophene):3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone)-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene)-based organic photodetectors with a structure of indium tin oxide/interlayer/active layer/MoOx/Al. With the selection of appropriate bottom electrode interlayer materials such as ZnO, PFN, and K2CO3, the devices show ultrahigh gain over the entire measured spectral range and good long-term stability. An optimized device with a ZnO interlayer exhibits a superior external quantum efficiency (EQE) of 19 300% at 360 nm, a detectivity of 2.15 × 1012 Jones at 600 nm, and a linear dynamic range of 98.36 dB under a bias voltage of −20 V. Moreover, the device also shows improved long-term stability that preserves 70% of its initial EQE after 120 h in the ambient environment without encapsulation.
Global computation of phase-amplitude reduction for limit-cycle dynamics
Authors: Mauroy A. , Mezić I.
Published: July 2018

Recent years have witnessed increasing interest in phase-amplitude reduction of limit-cycle dynamics. Adding an amplitude coordinate to the phase coordinate allows us to take into account the dynamics transversal to the limit cycle and thereby overcome the main limitations of classic phase reduction (strong convergence to the limit cycle and weak inputs). While previous studies, mostly focus on local quantities such as infinitesimal responses, a major and limiting challenge of phase-amplitude reduction is to compute amplitude coordinates globally, in the basin of attraction of the limit cycle. In this paper, we propose a method to compute the full set of phase-amplitude coordinates in the large. Our method is based on the so-called Koopman (composition) operator and aims at computing the eigenfunctions of the operator through Laplace averages (in combination with the harmonic balance method). This yields a forward integration method that is not limited to two-dimensional systems. We illustrate the method by computing the so-called isostables of limit cycles in two-, three-, and four-dimensional state spaces, as well as their responses to strong external inputs.
Tutorial: Coherent Raman light matter interaction processes
Authors: Rigneault Hervé , Berto Pascal
Published: July 2018

Coherent Raman scattering processes such as coherent anti-Stokes Raman scattering and stimulated Raman scattering are described in a tutorial way keeping simple physical pictures and simple derivations. The simplicity of the presentation keeps however most of the key features of these coherent and resonant processes and their intimate relation with spontaneous Raman scattering. This tutorial provides a digest of introduction to the fundamental physics at work, and it does not focus on the numerous technological implementations; rather, it provides the concepts and the physical tools to understand the extensive literature in this field. The presentation is made simple enough for under-graduate students, graduate students, and newcomers with various scientific backgrounds.
Comprehensive dependence of triboelectric nanogenerator on dielectric thickness and external impact for high electric outputs
Authors: Zhang Zhi , Sun Xiongfei , Chen Ying , Debeli Dereje Kebebew , Guo Jiansheng
Published: July 2018

Triboelectric nanogenerators (TENGs) have aroused extensive interests in recent years, and their energy conversion efficiency increased gradually under massive efforts. Applied force and dielectric thickness are two important factors accounting for the high output performance. Nevertheless, for the most commonly used TENGs in the contact-separation mode, the comprehensive dependence of dielectric thickness and impact force is still expected to be further deeply researched and optimized. Hence, we fabricated a nylon-PTFE TENG in the contact-separation mode and explored the dual influence of dielectric thickness and applied force on the output performance. The results indicate that the dielectric thickness and the magnitude of force have a comprehensive influence on the outputs, which is due to the dual effect of charge transport properties and the microcosmic deformation at different thicknesses. In general, the optimum thickness increases from 0.5 mm to 0.7 mm obviously as the force magnitude increases from 15 N to 60 N, but stays steadily with varying fabric count. With the continuous enlargement of impact force, the dielectric thickness reaches a boundary limitation of 0.8 mm. This work contributes greatly not only to the design and optimization of TENG devices, but also to the deeper understanding of the nano-triboelectric effect mechanism.
Fabrication of a corrosion resistant superhydrophobic surface on magnesium alloy substrate
Authors: Zhu Jiyuan , Bai Zigang , Dai XuanJun , Sun Baofu
Published: July 2018

Superhydrophobic surface was obtained on pretreated magnesium alloy substrates via Nano silver deposition and electroless Ni-P plating followed by stearic acid modification. The surface with hierarchical structure had a water contact angle of 157.8° and exhibited excellent superhydrophobicity. The surface morphology of the sample, the chemical compositions and wettability were characterized by scanning electron microscopy (SEM), XRD (X-ray diffraction), Fourier transformed infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and water contact angle measurement. The potential polarization curves revealed the corrosion resistance of superhydrophobic sample was enhanced as the corrosion current density decreased by 2 orders of magnitude.
Formation of power law spectra of energetic electrons during multiple X line magnetic reconnection with a guide field
Authors: Lu Quanming , Wang Huanyu , Huang Kai , Wang Rongsheng , Wang Shui
Published: July 2018

In this paper, with a two-dimensional particle-in-cell simulation model, we study the formation of power-law spectra of energetic electrons in multiple X line magnetic reconnection with a strong guide field. The processes of both magnetic reconnection and electron acceleration can be separated into two stages. In the first stage, two X lines appear at the border and center of the simulation domain, and then, two magnetic islands are formed. In this stage, electrons are accelerated mainly by parallel electric fields, and a power-law spectrum of energetic electrons is generated with the appearance of the second X line. In the second stage, the two magnetic islands are merged into one big island. Besides parallel electric fields, the Fermi mechanism also plays an important role in the production of energetic electrons, and its contribution is comparable to that of parallel electric fields when the electron energy is sufficiently large. In this stage, the generated power-law spectrum of energetic electrons becomes hard. In general, the acceleration efficiencies by both the parallel electric fields and Fermi mechanism become higher with the increase in electron energy, and the tendency is more obvious for the Fermi mechanism. Therefore, both the parallel electric fields and Fermi mechanism are important in the formation of power-law spectra of energetic electrons during multiple X line reconnection. We also investigate the influences of the ion-electron temperature ratio, guide field, and initial flux perturbation on the formed power-law spectra of energetic electrons.
Invited Article: Complex vibrational susceptibility by interferometric Fourier transform stimulated Raman scattering
Authors: Kumar Vikas , De la Cadena Alejandro , Perri Antonio , Preda Fabrizio , Coluccelli Nicola , Cerullo Giulio , Polli Dario
Published: July 2018

We introduce interferometric (I) Fourier-transform (FT) stimulated Raman scattering (SRS) to measure the complex nonlinear vibrational susceptibility of molecules. The technique is a simple variation of FT-SRS, which was previously demonstrated to combine the very high sensitivity of single-channel lock-in detection with the spectral resolution afforded by FT spectroscopy. In IFT-SRS, a local oscillator, temporally anticipated with respect to the broadband pump pulse, enables the interferometric detection of both real and imaginary parts of the nonlinear susceptibility, whose spectrum is recorded in the time domain by scanning the delay of the local oscillator using a birefringent common-path interferometer. We apply IFT-SRS to record the complex vibrational response of different solvents and their mixtures.
Exploring fractality of microcrystalline diamond films
Authors: Mitic Vojislav V. , Fecht Hans-Jörg , Mohr Markus , Lazovic Goran , Kocic Ljubisa
Published: July 2018

Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. The possibility to deposit polycrystalline diamond films via chemical vapor deposition (CVD) methods on large areas and on a large variety of substrates is posing numerous scientific challenges but also enables relevant industrial applications. Especially for small grain sizes, the grain’s misorientation and consequently the atomic structure of grain boundaries plays a significant role on transport properties and mechanical properties. Hence, the size and shape of the crystallites of poly- and nanocrystalline diamond films are one important key to optimize film properties for their specific applications. Fractal theory helps to find and define order in systems where disorder seems to prevail. Therefore, we apply fractal geometry analysis to characterize the grain morphology and surface topology of CVD grown diamond films.
Red Moon methodology compatible with quantum mechanics/molecular mechanics framework: Application to solid electrolyte interphase film formation in lithium-ion battery system
Authors: Fujie Takuya , Takenaka Norio , Suzuki Yuichi , Nagaoka Masataka
Published: July 2018

The Red Moon (RM) method [a hybrid Monte Carlo (MC)/molecular dynamics reaction method] is capable of realizing the practical atomistic simulation for complex chemical reaction systems beyond the range of application of the traditional molecular simulation techniques. In the RM method, the chemical reaction is treated stochastically based on the MC method. In the present study, to extend the applicability of the RM methodology, a new energy estimation method for the MC procedure has been proposed by using the quantum mechanics (QM)/molecular mechanics (MM) method. To validate its calculation reliability, we have examined it in a typical dimerization reaction in electrolytes of lithium-ion batteries (LIBs) and found that both solute internal energy and short-range solute-solvent interaction energy are significantly improved in comparison to the conventional energy estimation method using the MM method. As a practical application, we have dealt with the solid electrolyte interphase film formation in LIB, focusing on the bifurcation of dimerization reactions between the reduction products, and were able to reproduce the tendency similar to that in the experimental observations. It is concluded that the present RM methodology compatible with the QM/MM framework is expected to make a significant contribution to a variety of materials design and function development involved in various complex chemical reactions.
Simulations of splashing high and low viscosity droplets
Authors: Boelens Arnout M. P. , de Pablo Juan J.
Published: July 2018

In this work, simulations are presented for low viscosity ethanol and high viscosity silicone oil droplets impacting on a dry solid surface at atmospheric and reduced ambient pressure. The simulations are able to capture both the effect of the ambient gas pressure and liquid viscosity on the droplet impact and breakup. The results suggest that at early times droplet impact and gas film behavior for both low and high viscosity liquids share the same physics. However, at later times, during liquid sheet formation and breakup, high and low viscosity liquids behave differently. These results explain why for both kinds of liquids the pressure effect can be observed, while at the same time different high and low viscosity splashing regimes have been identified experimentally.
Numerical study of laminar boundary-layer flows over a superhydrophobic plate
Authors: Mei C. C. , Guo X. Y.
Published: July 2018

Liquid flow in the laminar boundary layer over a flat plate with a superhydrophobic surface formed by a square array of pillars is studied theoretically. Assuming the water surface on top of the pillars to be in the Cassie-Baxter state, asymptotic analysis is first carried out to separate the micro-scale flow in a typical cell surrounding a pillar and the macro-scale development of the laminar boundary layer of Blasius type. The 3-D cell problem and the 2-D boundary layer problem are solved together iteratively, yielding the slip length and the entire flow field. Numerical results are presented to examine the effect of solid fraction, pillar-to-pillar spacing, and the speed of the ambient flow on drag reduction. It is shown that the slip length is practically constant, while the boundary layer thickness grows monotonically downstream so that hydrophobicity affects drag reduction primarily over the leading portion of a long surface.
Study of adhesion and friction drag on a rough hydrophobic surface: Sandblasted aluminum
Authors: Li Longyang , Zhu Jingfang , Zhi Shudi , Liu Eryong , Wang Gang , Zeng Zhixiang , Zhao Wenjie , Xue Qunji
Published: July 2018

Roughness is a crucial prerequisite for fabricating superhydrophobic surfaces. However, the enormous economic cost of fabricating rough surfaces seriously limits the industrial application of superhydrophobic surfaces. To overcome this drawback, we present herein a simple, low cost, user-friendly, and rapid method to fabricate rough surfaces with micro- and nanostructured features. By modifying the sandblasting pressure, we fabricated aluminum surfaces of varying roughness, which we then decorated with polydimethylsiloxane to reduce the surface energy. The contact angle, slip velocity, slip length, and drag-reduction ratio all increase with increasing sandblasting pressure, and the maximum contact angle of a droplet, the slip velocity, the length, and the drag-reduction ratio are 151.74 ± 1°, 0.1617 m/s, 0.04276 mm, and 19.2%, respectively, for a sandblasting pressure of 0.8 MPa. The adhesive force of the samples decreases with increasing sandblasting pressure to a minimum of 0.096 mN. The process by which trapped air escapes from the sample surface is visualized by using fluent software, and the results show that the low adhesive and low friction properties of the superhydrophobic surface, which are due to air being trapped in the space between protrusions, may effectively prevent water from moving into these spaces.
Stability of plane Couette flow of Carreau fluids past a deformable solid at arbitrary Reynolds numbers
Authors: Tanmay Velidanda S. , Patne Ramkarn , Shankar V.
Published: July 2018

The linear stability of the plane Couette flow of both power-law and Carreau fluids past a deformable, neo-Hookean solid is analyzed at arbitrary Reynolds numbers. An algebraic error in the mathematical formulation of the earlier studies (for the power-law fluid) is corrected and is shown to result in quantitative differences in the predictions for the stability of the flow. Due to the lack of a proper (zero-shear) viscosity scale and a time scale for the onset of shear thinning in the power-law model, we show that the stability analysis of the flow yields vastly different scalings for the unstable mode depending on the way the problem is scaled to render it dimensionless. When the deformable solid properties are used to non-dimensionalize, we show that for the unstable modes (the so-called “wall modes” at high Re) Γc∝Re−1(2n+1), while when flow properties are used to non-dimensionalize, Γc∝Re−13 much akin to a Newtonian fluid, where Γ=Vm*η*/G*R* is the dimensionless shear rate in the flow, and Γc denotes the minimum value required for instability. Here, Vm* is the velocity of the top plate, G* is the shear modulus of the solid, R* is the fluid thickness, and η* is the (arbitrary) viscosity scale in the power-law model. Within the framework of the power-law model, it is not possible to discriminate between the two predicted scalings. To resolve this in an unambiguous manner, we used the Carreau model to account for shear thinning and to study its role on the stability of flow past deformable solid surfaces. The Carreau model has a well-defined zero-shear viscosity η0* as well as a time scale λ* that characterizes the onset of shear thinning. For fixed λ*η0*/(ρ*R*2), we show that the unstable wall modes scale as Γc∼Re(1−2n)3 at high Re, thus providing a resolution to the ambiguity in the results obtained using the power-law model. The present work thus shows that, at moderate to high Re, shear thinning has a strongly stabilizing effect on the wall mode instability in flow past deformable solid surfaces.
Universal effects of solvent species on the stabilized structure of a protein
Authors: Hayashi Tomohiko , Inoue Masao , Yasuda Satoshi , Petretto Emanuele , Škrbić Tatjana , Giacometti Achille , Kinoshita Masahiro
Published: July 2018

We investigate the effects of solvent specificities on the stability of the native structure (NS) of a protein on the basis of our free-energy function (FEF). We use CPB-bromodomain (CBP-BD) and apoplastocyanin (apoPC) as representatives of the protein universe and water, methanol, ethanol, and cyclohexane as solvents. The NSs of CBP-BD and apoPC consist of 66% α-helices and of 35% β-sheets and 4% α-helices, respectively. In order to assess the structural stability of a given protein immersed in each solvent, we contrast the FEF of its NS against that of a number of artificially created, misfolded decoys possessing the same amino-acid sequence but significantly different topology and α-helix and β-sheet contents. In the FEF, we compute the solvation entropy using the morphometric approach combined with the integral equation theories, and the change in electrostatic (ES) energy upon the folding is obtained by an explicit atomistic but simplified calculation. The ES energy change is represented by the break of protein-solvent hydrogen bonds (HBs), formation of protein intramolecular HBs, and recovery of solvent-solvent HBs. Protein-solvent and solvent-solvent HBs are absent in cyclohexane. We are thus able to separately evaluate the contributions to the structural stability from the entropic and energetic components. We find that for both CBP-BD and apoPC, the energetic component dominates in methanol, ethanol, and cyclohexane, with the most stable structures in these solvents sharing the same characteristics described as an association of α-helices. In particular, those in the two alcohols are identical. In water, the entropic component is as strong as or even stronger than the energetic one, with a large gain of translational, configurational entropy of water becoming crucially important so that the relative contents of α-helix and β-sheet and the content of total secondary structures are carefully selected to achieve sufficiently close packing of side chains. If the energetic component is excluded for a protein in water, the priority is given to closest side-chain packing, giving rise to the formation of a structure with very low α-helix and β-sheet contents. Our analysis, which requires minimal computational effort, can be applied to any protein immersed in any solvent and provides robust predictions that are quite consistent with the experimental observations for proteins in different solvent environments, thus paving the way toward a more detailed understanding of the folding process.