Larger N-value Research Articles

A case series evaluating the impact of Hepatitis C eradication using direct acting antivirals on primary biliary cholangitis-associated autoimmunity

BackgroundChronic Hepatitis C Virus (HCV) infection has been commonly linked to the development of autoimmunity, in part through activation of B cells. B cells are also postulated to play a pathogenic role in the autoimmune liver disease Primary Biliary Cholangitis (PBC). Patients with concurrent PBC and HCV infection carry an increased risk of more progressive disease, although the mechanism underlying this effect is poorly understood. Utilizing a case series of patients with concurrent PBC and HCV, the aim of this study was to evaluate for the potential impact of HCV eradication upon autoimmunity/autoantibody production.Case presentationA case series evaluating three patients with co-existing PBC-HCV infection receiving non-interferon based HCV treatments with direct-acting antivirals (DAA). One of three patient received Ursodeoxycholic acid (UDCA; 13 mg/kg/day) during the treatment period. Sustained virological response (SVR) to DAA’s was assessed using a HCV Quantitative Nucleic Acid Test (Abbott). Autoantibodies associated with autoimmune liver diseases (including PBC) and liver biochemistry, were measured before, during and after DAA treatment (Mitogen Advanced Diagnostics Laboratory, Calgary, Canada).All patients achieved an SVR, as determined by negative HCV RNA test 12 weeks post-DAA therapy. Titres of anti-mitochondrial antibodies (AMA-M2), anti- branched-chain 2-oxo-acid dehydrogenase complex and 2-oxo glutarate dehydrogenase complex (anti-3E-BPO), and anti- tripartite motif-containing protein 21 (TRIM21/Ro52) remained unchanged, despite successful HCV eradication. Two of the three patients exhibited a transient decrease in some autoantibody titres during DAA treatment, but these returned to baseline levels post-DAA therapy.ConclusionsWithin the limitations of a case series, our results suggest that HCV co-infection may not be a significant driver of PBC-related autoimmunity/autoantibody production. However, a larger n-value is required to truly assess for the effect of HCV eradication on autoantibody production.

Influence of Continuous Bending Process on Texture Evolution and Mechanical Properties of AZ31 Magnesium Alloy

Mg–3Al–1Zn alloy sheets have been deformed by continuous bending (CB) to investigate the effects of processing parameters (bending angle and repetitive passes) on the texture and formability. The samples exhibited a bimodal microstructure with abnormal growth grains in the surface region and fine grains distributed in the center after CB process followed by annealing. The texture evolution measured by XRD indicated that the basal poles were rotated from ND toward RD, and the texture intensity decreased with the bending angle decreasing and repetitive passes increasing. Compared with the as-received sample, the yield strength of CBA-120-2 sample significantly decreased from 183 to 112 MPa, and a smaller r-value and a larger n-value were obtained. The formability of CB processed samples in annealing condition was significantly enhanced with the highest of Erichsen value of 5.4 mm, increased by about 135%. The improvement of formability was likely attributed to the weakened and RD-tilt basal texture and coarse grains in the surface part.

Simulation of Critical Currents in Bulk Superconductors by Modified FEA and Hybrid Methods

A modified finite-element analysis (FEA) and hybrid numerical-analytical method for simulation of critical currents and magnetic fields in high-temperature bulk superconductors are discussed. It is shown that the hybrid method is more robust and efficient in terms of speed and accuracy as compared with the known integral method. The modified FEA method is more stable than a conventional transient solution especially at large n-value in J-E relation.

Effect of the final rolling speeds on the stretch formability of AZ31 alloy sheet rolled at a high temperature

The influence of final rolling speeds varying from 0.1 m/s to 0.4 m/s on the microstructures, textures, mechanical properties and stretch formability of AZ31 alloy sheets rolled at 550 °C was investigated in the present work. The results showed that in as-rolled condition, with increasing the final rolling speed, the grain size of the sheets increased whereas the basal texture intensity decreased. Twinning was still the main deformation behaviour even at high final rolling speed. After annealing, the sheets exhibited double-type textures with basal poles tilting at approximately from ±10° to ±12° in the rolling direction, and the basal texture weakened more remarkably via static recrystallization for the sheets rolled at higher final speed. By increasing the final rolling speeds from 0.1 m/s to 0.4 m/s, the Erichsen values of the annealed sheets at room temperature were enhanced from 4.9 mm to 6.3 mm resulted from the weakened basal texture, which leaded to a lower 0.2% proof stress, r-value, and a larger n-value. The main reasons for the twinning behaviour and weakened textures at high final rolling speeds were discussed.

Advanced organic dye for high-speed, high-density optical media

Advances in organic dye progress are indispensable for high-speed, high-density recording of recordable Blu-ray Disc™ (BD-R) low-to-high (LTH) discs without a low elastic modulus layer. The optimal physical properties of the organic dyes, i.e., a low decomposition calorific value, a low decomposition temperature, and a large n-value, were determined, and a dye with these properties was synthesized. A BD-R disc using the dye conformed to the BD-R LTH standard at 8× recording and ever higher speeds should be possible. Furthermore, the possibility of 33 GB/layer high-density recording was suggested.

Prediction of Surface Roughening and Necking Behavior for Metal Foils by Inhomogeneous FE Material Modeling

Micro metal forming with metal foils is one of the promising approaches to fabricate micro parts. In this study, a finite element (FE) model for metal foil considering material inhomogeneity due to different flow stresses for each crystal grain to predict free surface roughening and necking behavior is suggested. Material used is pure copper C1020-O, pure aluminum 1N30-O and pure titanium TR270C-O with thickness of 0.05mm. Material inhomogeniety parameter of variation in α value is determined by parameter fitting between uni-axial tensile test and FE analysis considering material inhomogeneity under uni-axial tensile state. Standard deviation σsd of variation in α value of 0.28 for C1020-O is obtained by parameter fitting process. In addition, free surface roughening behavior is observed by FE analysis considering material inhomogeneity and confocal laser microsope. As a result, the increase in surface roughness with uni-axial tensile deformation can be observed for both FE analysis and experiment. In addition, it is considered that the generation of concave parts in free surface roughening is due to grains with low flow stress by quantitative measurement of FE analysis and confocal laser microscope. Surface roughening behavior of FE analysis considering material inhomogeneity is in good agreement with that of experimental results. Thus, the validation of FE model considering material inhomogeniety for metal foils can be verified. Furthermore, the effect of material properties for metal foils such as grain size, material inhomogeneity parameters and strain hardening sensitivity on necking behavior is investigated. As a results, it is found that the ratio of surface roughening to thickness strongly affects necking behavior for metal foil. In particular, in case of large n-value, the concave part generated by surface roughening during plastic deformation would cause the onset of necking for metal foils. Therefore, it is found that the factor of surface roughening is very strong in micro metal forming with metal foils.

A 2-D Robust FE-FV Mixed Method to Handle Strong Nonlinearities in Superconductors

A robust numerical method based on 2-D mixed finite-elements-finite volumes (FE-FV) allows the solution of diffusion problems in superconducting (SC) materials. The proposed approach handles the strong nonlinearity of the E(J) constitutive power law of high-temperature superconductors (HTS). The method is tested for a SC cylinder submitted to a sinusoidal transport current or to a transverse sinusoidal external field. The current density distributions as well as the AC losses are computed. Comparisons to a FE analyses that use the magnetic field as state variable show the validity of the proposed approach. It can be seen that the proposed method is very stable even for large n-values for which the FE method does not converge.

New Hybrid FE-FV Method for Computing Current Distribution in 2-D Superconductors: Application to an HTS Cylinder in Transverse Magnetic Field

This paper presents a new numerical method based on finite elements - finite volumes (FE-FV) for solving 2-D diffusion problems in high temperature superconductors (HTS). The approach does not involve directly the resistivity term (rho), generally used to model the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> ) characteristic as a power law, i.e <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> ) = rho( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> ) <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> , with rho( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> ) prop <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n-1</sup> . Instead, we use a <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> ) constitutive law <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> prop <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(1/n)</sup> , with <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rarr</sup> = <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ee</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rarr</sup> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> (a single component), which leads to a scalar non-linear differential equation. After presenting in details the developments, the method is tested in the case of a superconducting cylinder submitted to a transverse magnetic field. The current density obtained is compared to another numerical technique (the semi-analytical method) in order to validate the results. Although not fully optimized yet, it appears that the proposed method is very stable, especially for large n-values (greater than 100).

Numerical simulation of the magnetization of high-temperature superconductors: a 3Dfinite element method using a single time-step iteration

In this paper, we report progress towards a 3D finite element model for the magnetizationof a high-temperature superconductor (HTS): we suggest a method that takes intoaccount a power law conductivity and demagnetization effects, while neglecting theeffects associated with currents that are not perpendicular to the local magneticinduction. We consider samples that are subjected to a uniform magnetic fieldvarying linearly with time. Their magnetization is calculated by means of a weakformulation in the magnetostatic approximation of the Maxwell equations (A–ϕ formulation). An implicit method is used for the temporal resolution (backwardEuler scheme) and is solved with the open source solver GetDP. Fixedpoint iterations are used to deal with the power law conductivity of HTS.The finite element formulation is validated for an HTS tube with largen value by comparing with results obtained with other well-established methods. We showthat carrying out the calculations with a single time-step (as opposed to many smalltime-steps) produces results with excellent accuracy in a drastically reduced simulationtime. The numerical method is extended to the study of the trapped magnetization ofcylinders that are drilled with different arrays of columnar holes arranged parallel to thecylinder axis.

Correlations between ε′/ε and rareKdecays in the Littlest Higgs model with T-parity

We calculate the CP-violating ratio epsilon'/epsilon in the Littlest Higgs model with T-parity (LHT) and investigate its correlations with the branching ratios for K_L -> pi^0 nu {bar nu}, K_L -> pi^0 l^+ l^- and K^+ -> pi^+ nu {bar nu}. The resulting correlations are rather strong in the case of K_L decays, but less pronounced in the case of K^+ -> pi^+ nu {bar nu}. Unfortunately, they are subject to large hadronic uncertainties present in epsilon'/epsilon, whose theoretical prediction in the Standard Model (SM) is reviewed and updated here. With the matrix elements of Q_6 (gluon penguin) and Q_8 (electroweak penguin) evaluated in the large-N limit and m_s^MS(2 GeV) = 100 MeV from lattice QCD, (epsilon'/epsilon)_SM turns out to be close to the data so that significant departures of Br(K_L -> pi^0 nu {bar nu}) and Br(K_L -> pi^0 l^+ l^-) from the SM expectations are unlikely, while Br(K^+ -> pi^+ nu {bar nu}) can be enhanced even by a factor 5. On the other hand, modest departures of the relevant hadronic matrix elements from their large-N values allow for a consistent description of epsilon'/epsilon within the LHT model accompanied by large enhancements of Br(K_L -> pi^0 nu {bar nu}) and Br(K_L -> pi^0 l^+ l^-), but only modest enhancements of Br(K^+ -> pi^+ nu {bar nu}).

Mechanical Properties and Formability of AZ31 Magnesium Alloy Processed by Differential Speed Rolling

An AZ31 (Mg-3Al-1Zn-0.35Mn in mass%) alloy sheet exhibiting the inclination of the basal plane from the rolling plane at about 15º, was fabricated by a DSR processing with a roll speed ratio of 1.167. Compared with the normal rolled sheets, the DSR processed sheets showed a lower 0.2% proof stress, a larger elongation, a smaller r-value and a larger n-value. The Erichsen value at room temperature significantly increased from 2.2 to 3.1, and the deep drawability also improved.

Characterization of Electrical Properties of Micro-Schottky Contacts on Epitaxial Lateral Overgrowth GaN

Current-voltage characteristics of micro-Schottky contacts fabricated on Epitaxial lateral overgrowth (ELO) GaN have been measured. The obtained characteristics are classified into two groups; good contacts with small ideality factor (n-value) and poor contacts with large n-value. By comparing the distribution of I-V characteristics of the micro-Schottky contact array with the distribution of dislocations revealed by molten KOH etching, it was concluded that the dislocations are not responsible for the poor I-V characteristics of the Schottky contacts. Regarding the origin of the poor I-V characteristics, the high doping density area formed at the top surface of the as-grown wafer was suggested.

Unusually large numbers of electrons for the oxidation of polyphenolic antioxidants

Reaction mechanisms of polyphenolic antioxidants were studied using electrochemical methods (flow column electrolysis and cyclic voltammetry). In flow column electrolysis, the numbers (ns) of electrons involved in the oxidation of catechols (chlorogenic acid and caffeic acid) became larger than two (i.e. the number of –OH moieties) at pH>7; the n-values finally reached ca. 4 at pH 10. Other polyphenols including catechin, ellagic acid, and curcumin exhibited higher n-values than the numbers of –OH moieties in the whole pH range studied (4<pH<10). Such unusually large n-values for polyphenols were found to correlate to their irreversible behavior in cyclic voltammetry. A digital simulation analysis of the voltammograms of chlorogenic acid clearly showed that the electrode reaction at higher pHs can be elucidated in terms of a quasi-reversible electron transfer followed by a chemical reaction and also suggested that the chemical reaction is of second order to the concentration of chlorogenic acid, i.e. a dimerization reaction. In a similar manner, polyphenolic antioxidants generally undergo certain chemical reactions on the occasion of their oxidation. As a result, some oxidizable, phenolic –OH moieties are reproduced in the polymeric products. The unusually large n-values of polyphenols and thus their higher radical scavenging activities may be ascribed to such reproduction of –OH moieties by oxidative polymerization.

Magnetically investigated E– J characteristics of Bi-2212/Ag tape conductors

We evaluated the E– J characteristics of several Bi-2212/Ag tapes and a Bi-2212 single crystal by the magnetization method. Tapes were prepared under oxygen partial pressure of 0.2 atm (20% O 2) and 1.0 atm (100% O 2). 180 MeV Cu 11+-irradiated tapes were also prepared. The slope of log E–log J curves for the tapes was larger than that of the single crystal at all temperatures and fields investigated. At 5 K, the log E–log J curves of all samples showed linear behavior. The slope of the curve with an n-value of ∼45 was obtained in low fields for the 20% O 2 sample. This n-value decreased to ∼19 at 4 T. The 100% O 2 sample showed larger n-values than the 20% O 2 sample. This enhancement of n-values is attributed to the improved pinning characteristics introduced by an over-doping of carriers. Cu 11+ irradiation significantly enhanced n-values at low fields. However, the large n-value decreased rapidly with increasing the field, and, at 4 T, the n-value of the irradiated sample was nearly equal to that of the non-irradiated sample. At 25 K, log E–log J curves were no longer linear in fields above ∼1.5 T except for the irradiated sample.

Electron binding to valence and multipole states of molecules: Nitrobenzene, para- and meta-dinitrobenzenes

Nitrobenzene anions (NB−) in both valence and dipole bound states are examined using laser (photodetachment) photoelectron and Rydberg electron transfer (RET) spectroscopies. Photoelectron spectroscopy of the valence NB− anion yields a valence (adiabatic) electron affinity of 1.00±0.01 eV. The reaction rates for charge transfer between atoms of cesium and xenon in high Rydberg states [Cs(ns,nd) and Xe(nf )] and NB exhibit a prominent peak in their n-dependencies consistent with the formation of a dipole bound anion having an electron affinity of 28 meV. Para-dinitrobenzene (pDNB) has a zero dipole moment and a large quadrupole moment. RET studies with pDNB show a complex n-dependence. The rate of formation of pDNB− ions exhibits a broad peak at low n-values and a second very broad feature extending to large n-values. The peak at low n is tentatively attributed to charge exchange into a quadrupole bound state (EAqb=25 meV). The absence of field-detachment for these ions suggests that if these are in a quadrupole bound state they are strongly coupled to the valence state. Meta-dinitrobenzene (mDNB) has a large dipole moment and a small quadrupole moment. The observation of a weak but narrow peak at a low n-value in the RET measurement is consistent with electron attachment into a primarily dipole bound state (EAdb=68 meV) which is also strongly coupled to the valence state.

Factors affecting stretching limits of Aluminum sheet

The purpose of the present paper is to study methods to improve the stretching limit of metal sheet. The factors affecting the stretching limit were sheet thickness, blank diameter, blank holding pressure, and forming rate. Punch radius, die radius, and clearance between a punch and a die were retained constant. Tested materials were softened and half hardened types of aluminum sheet. The effect of lubrication was also studied. Lubricants used were a press working oil and graphite. Stretching by two types of punch shape, a spherical head punch and a truncated cone one, was tried in order to research the effect of punch shape. The half hardened aluminium, which has a larger n-value, showed the larger stretching limit. The larger thickness gave rise to the larger stretching limit. Flow characteristic of materials was poorer in larger diameter of a blank, so its stretching limit was lower. A bit lower holding pressure, which allows drawing of materials to some extent, yielded larger stretching limit than rigid holding. The forming rate did not so much affect stretching limit. Concerning the effect of lubrication, applied position of lubricants was important.

Structure of polygonal defects in graphitic carbon sheets.

Various polygonal defects which retain the three-bonded character of carbon are proposed as disclinations in graphitic carbon. The n-gonal defects, where n is an integer less than 5, are responsible for forming cones and are less stable than pentagonal defects in a hexagonal network which are responsible for forming spherical fullerenes such as ${\mathrm{C}}_{60}$. On the other hand, the n-gonal defects, where n is greater than 6, correspond to negative wedge disclinations on the surface and leads to a negatively curved surface. Using molecular-dynamics simulations, it is found that the surfaces containing 10(deca)-, 11(hendeca)-, or 12(dodeca)-gonal defects are more stable than similarly shaped surfaces containing a multiple number of heptagons. It is also found that the surfaces which contain an n-gonal defect (with a large-n value) with a periodic folding of the surface are stable for some cases. The buckled surface with an 18(octadeca)-gonal defect in particular, which is rolling with surface distortions bending upward and downward three times around the defect, gives a stable structure. Our considerations indicate that complex structures not considered before could possibly exist. The relation of screw dislocations to polygonal defects, and their stability, are also studied. \textcopyright{} 1996 The American Physical Society.