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ABSTRACTThe influence of mould level instability during continuous casting on the unevenness of the initial solidified shell in hypo-peritectic steels has been investigated. Water model experiments and in-plant casting experiments revealed that mould level instability, which increases with increasing casting speed, is related to longitudinal cracking resulting from the unevenness of the solidification shell. A numerical model which considers the effect of mould level instability was developed and used to simulate the formation of the unevenness of the solidification shell and solidified shell deflections. The calculation results show that an increase in the non-uniform infiltration of mould flux increases the unevenness of the solidified shell. On the other hand, the unevenness of the solidified shell decreases due to mild cooling. Overall, the results of the plant tests and calculations show that non-uniform infiltration of mould flux dramatically affects air gap formation and the unevenness of the solidified shell.

The influence of mould level instability during continuous casting on the unevenness of the initial solidified shell in hypo-peritectic steels has been investigated. Water model experiments and in-plant casting experiments revealed that mould level instability, which increases with increasing casting speed, is related to longitudinal cracking resulting from the unevenness of the solidification shell. A numerical model which considers the effect of mould level instability was developed and used to simulate the formation of the unevenness of the solidification shell and solidified shell deflections. The calculation results show that an increase in the non-uniform infiltration of mould flux increases the unevenness of the solidified shell. On the other hand, the unevenness of the solidified shell decreases due to mild cooling. Overall, the results of the plant tests and calculations show that non-uniform infiltration of mould flux dramatically affects air gap formation and the unevenness of the solidified shell.

ABSTRACTBackgroundThe safety of Ramadan fasting for Muslim patients suffering from multiple sclerosis (MS) is still a matter of debate. This work aimed to study the clinical course of MS during Ramadan fasting and to clarify the predictors of relapses and symptoms exacerbation.MethodsThis retrospective study included 153 Muslim patients with MS. Data related to the disease course before Ramadan were obtained from patients' files, whereas data related to the disease activity during Ramadan, were collected from patients over the two months following Ramadan.ResultsPatients with MS who experienced relapses, exacerbation of symptoms and development of new symptoms during Ramadan had a statistically significant longer disease duration compared to those who did not experience (P < 0.001, <0.001, 0.01 respectively). Also, patients who experienced relapses, exacerbation of symptoms and development of new symptoms during Ramadan had a statistically significant higher expanded disability status scale (EDSS) compared to those who did not experience (P <0.001, <0.001,0.01, respectively). The occurrence of relapses, exacerbation of symptoms and development of new symptoms during Ramadan, were significantly higher in patients who experienced relapses in the preceding year compared to those who did not (P= 0.002, 0.002, 0.01, respectively). Binary logistic regression revealed that each score elevation of EDSS increased the odds of relapse during Ramadan by 1.02 (P-value = 0.04). Also, each month's increase in disease duration increased the odds of relapse during Ramadan by 1.87 (P-value = 0.046).ConclusionHigh EDSS and long disease duration are independent predictors of relapse during Ramadan.

Increasing the yield strength of austenitic steel without significantly sacrificing ductility has been a long-standing technical challenge. Here, we obtained an ultrahigh yield strength (∼1.4 GPa) and ductile (∼37% uniform elongation) austenitic steel through innovatively combining cold rolling, flash annealing, and tempering (CFT) processes. Such CFT steel shows a heterogeneous lamellar microstructure composed of reversed austenite and partially recrystallized austenite. The ultrahigh yield strength is attributed to the synergistic strengthening mechanisms induced by high-density dislocations, nano/ultrafine grains, and nanoscale precipitates. The achieved high ductility is associated with the pronounced transformation-induced plasticity (TRIP) effect induced by the high-density dislocations combined with the twinning-induced plasticity (TWIP) effect induced by grain refinement. Such a strengthening and plasticity mechanism paves the way for a processing route to achieve ultrahigh strength-high ductility combination in austenitic steel. [Display omitted] [ABSTRACT FROM AUTHOR]

The aim of present work is to develop a crystal plasticity modeling approach to integrate slip, dynamic recrystallization (DRX) and grain boundary sliding (GBS) for simulating the deformation behavior and texture evolution of magnesium alloys at high temperatures. Firstly, the deformation mechanisms of an AZ31B Mg alloy sheet at 300 °C were investigated by examining texture and microstructure evolution during uniaxial tension and compression tests. DRX refines microstructure at strains less than 0.2, and subsequently GBS plays a significant role during deformation process. A GBS model is developed to evaluate strain and grain rotation induced by GBS, and implemented into the polycrystal plasticity framework VPSC. The VPSC-DRX-GBS model can well reproduce the stress−strain curves, grain size, texture evolution and significant texture differences in tension and compression tests due to GBS. The calculated GBS contribution ratio in tension is obviously higher than that in compression due to easier cavity nucleation at grain boundaries under tension loading.

Abstract: Total 40 natural compounds were selected to perform the molecular docking studies to screen and identify the potent antiviral agents specifically for Severe Acute Respiratory Syndrome Coronavirus 2 that causes coronavirus disease 2019 (COVID-19). The key targets of COVID-19, protease (PDB ID: 7BQY) and RNA polymerase (PDB ID: 7bV2) were used to dock our target compounds by Molecular Operating Environment (MOE) version 2014.09. We used 3 different conformations of protease target (6M0K, 6Y2F and 7BQY) and two different score functions to strengthen the probability of inhibitors discovery. After an extensive screening analysis, 20 compounds exhibit good binding affinities to one or both COVID-19 targets. 7 out of 20 compounds were predicted to overcome the activity of both targets. The top 7 hits are, flacourticin (3), sagerinic acid (16), hordatine A (23), hordatine B (24), N-feruloyl tyramine dimer (25), bisavenanthramides B-5 (29)and vulnibactins (40). According to our results, all these top hits was found to have a better binding scores than remdesivir, the native ligand in RNA polymerase target (PDB ID: 7bV2). Hordatines are phenolic compounds present in barley, were found to exhibit the highest binding affinity to both protease and polymerase through forming strong hydrogen bonds with the catalytic residues, as well as significant interactions with other receptor-binding residues. These results probably provided an excellent lead candidate for the development of therapeutic drugs against COVID-19. Eventually, animal experiment and accurate clinical trials are needed to confirm the preventive potentials of these compounds. Graphic Abstract:

Both ausforming and austempering below the martensite start temperature (MS) have been shown to accelerate the bainitic transformation. This work investigates the combined effects of deformation and austempering below the MSon the isothermal transformation kinetics, microstructure, and hardness in a medium-carbon bainitic steel. The results show that, deformation below the MScan delay the onset of the baintic transformation compared to the case in which no deformation is applied. The larger the amount of martensite presents prior to the deformation step, the greater the delay in the onset of bainitic transformation. This behavior is attributed to the development of strong misorientation gradients within austenite during the co-deformation of the austenite-martensite microstructure. These large misorientation gradients make the pre-existing martensite a less effective nucleation site for bainite.

•Multiple sclerosis (MS) is one of the leading causes of disability in young adults. The onset of MS during developmental age makes pediatric patients particularly susceptible to cognitive impairment.•An early and systematic neuropsychological assessment is recommended in pediatric onset MS) POMS) for appropriate counselling and management.•BICAMS is a feasible approach to cognitive screening in POMS and adults.•Arabic version of BICAMS is a reliable and valid tool for the cognitive assessment of pediatric MS patients in different clinical and research settings.

This work was designed to study the dynamics of transmission of Newcastle disease virus (NDV), genotype VIId, from Muscovy ducks (Cariana moscata) infected either by intramuscular (IM) or intranasal (IN) inoculation, to in-contact broiler chickens (Gallus gallus). IM-infected Muscovy ducks (G1d) exhibited only 5% mortality, and the concentration of virus shed from the cloaca was greater and for longer period than virus shed from the trachea. In contrast, IN-infected ducks (G2d) exhibited no mortality, and virus shedding from the trachea was higher than that from the cloaca starting from 4 days post infection (dpi) and continued up to 16 dpi, while in IM-infected ducks (G1d), tracheal shedding stopped at 11 dpi. Chickens in contact with IM-infected and IN-infected ducks, G1c and G2c, respectively, not only developed severe clinical symptoms and death (80% and 20% mortality, respectively), but also shed the virus at higher concentrations than infected ducks. G1c chickens had higher viral shedding titers in both the trachea and cloaca than G2c chickens until 11 dpi. All broiler chickens infected by IM route (G3c) died, while the IN route of infection resulted in lower mortality (70%) in G4c. Generally, all IM-infected birds produced an earlier and higher level of NDV hemagglutination inhibition (HI) antibody titer, along with higher rates and shorter periods of viral shedding than those infected by the intranasal route. Our conclusion is that Muscovy ducks are efficient carriers of NDV-genotype VIId and transmit the virus to contact chickens.

ABSTRACTMedium-to-high carbon hot-rolled steel strip was developed on a thin slab casting direct strip production complex at Essar Steel Algoma Inc. to meet different specifications and special customer requirements. The effects of chemistry, casting and hot rolling process parameters on microstructure and mechanical properties were studied. Soft core reduction, secondary cooling, casting speed, as well as hot rolling and coiling temperature were optimised to achieve the required mechanical properties and other requirements such as ultrasonic test after electric resistance welding, wear resistance and corrosion resistance. These new developed medium-to-high carbon steel grades have extensive applications in oil and gas industries, general manufacturing, construction, automotive and mining equipment.

Medium-to-high carbon hot-rolled steel strip was developed on a thin slab casting direct strip production complex at Essar Steel Algoma Inc. to meet different specifications and special customer requirements. The effects of chemistry, casting and hot rolling process parameters on microstructure and mechanical properties were studied. Soft core reduction, secondary cooling, casting speed, as well as hot rolling and coiling temperature were optimised to achieve the required mechanical properties and other requirements such as ultrasonic test after electric resistance welding, wear resistance and corrosion resistance. These new developed medium-to-high carbon steel grades have extensive applications in oil and gas industries, general manufacturing, construction, automotive and mining equipment.

ABSTRACTThe kinetics of the Cr2O3-based scale oxidation and volatilisation were studied in the presence of water vapour (H2O). A commercial Cr2O3-based scale forming Type 310S stainless steel was examined at the ambient pressure (0.1 MPa) and 550°C in relatively low and high H2O-containing environments of air-10% H2O and air-70% H2O, respectively. The increase in the partial pressure of H2O (pH2O) from 10 to 70% resulted in the transition of the oxidation and volatilisation kinetics from the parabolic rate law in air-10% H2O to the paralinear rate law in air-70% H2O. The kinetics transition was attributed to the increase in the Cr loss rate from the base scale after coupons exposure in air-70% H2O. The significant role of Mn alloying element in the base scale protectiveness was also discussed in the context of the Cr2O3-based scale stability.

Objectives: To evaluate the diagnostic yield of skin prick test (SPT) and serum total immunoglobulin E (IgE) antibodies level in patients with allergic rhinitis (AR) and the role of nasal provocation test (NPT) for the determination of local allergic rhinitis (LAR) in patients with nonallergic rhinitis (NAR).Methodology: This multi-center study included 1230 patients with clinical manifestations for ≥2 years. Patients were classified according to the Allergic Rhinitis and Its Impact on Asthma (ARIA) and scored according to the quantitative Score for Allergic Rhinitis (SFAR). The SPT and total IgE antibody levels were done for all patients. Patients gave negative SPT underwent NPT, and its result was interpreted using Lebel Symptom Score Scale.Results: The SPT was positive in 77.8% of patients, mostly for grass pollen and dust mites. All patients were sensitive to multiple allergens. Median serum IgE antibody level for total study population was 162 IU/ml. Forty-two patients (3.4%) with negative SPT showed a weak response to NPT, while 231 patients (18.7%) with negative SPT had a high response to NPT and were considered to have LAR.Conclusion: The SPT could discriminate between AR and NAR patients. The NPT could identify LAR in 84.6% of patients with rhinitis among those considered as NAR.

Microalloying additions are critical for grain size control during thermo-mechanical processing. The addition of niobium is known to delay the onset and growth of recrystallization. A physically-based model for the interaction of strain-induced precipitation, recovery and recrystallization is presented. A key feature of the model is the incorporation of the effect of precipitation on the nucleation of recrystallization. Quantitative agreement between the experimental measurements and the model predictions has also been demonstrated. The model offers valuable insight into the relative contributions of solute and precipitate Nb as well as the optimum conditions for strain accumulation.

The effect of solute niobium in retarding coarsening kinetics of austenite in upstream thermo mechanical processing of high niobium (0.1wt%Nb) low interstitial steel is analyzed. Solute drag effect of niobium in retarding boundary mobility in static recrystallization is examined in thermo-mechanical rolling of high Nb microalloyed steel. The importance of austenite grain refinement prior to pancaking in compact strip rolling of high Nb microallyed steel as a means to increase surface area to volume ratio of pancaked austenite grain is emphasized. This is to promote adequate nucleation sites for phase transformation even under conditions low total rolling reduction below temperature of no recrystallization.

Stress relaxation was studied in a series of low carbon, high Mn microalloyed steels containing 0.012, 0.06 and 0.1 wt% Nb. The stress-relaxation curves were modeled using a physically-based model that takes into account the time evolution of precipitation, recovery and recrystallization as well as their interactions. The results confirm that high Mn-high Nb design can offer distinct advantage over the low-Mn design for the application of near net shape processing.

A physically-based model for nucleation during discontinuous dynamic recrystallization (DDRX) has been developed and is coupled with polyphase plasticity and grain growth models to predict the macroscopic stress and grain size evolution during straining. The nucleation model is based on a recent description for static recrystallization and considers the dynamically evolving substructure size. Model predictions are compared with literature results on DDRX in pure Cu as a function of initial grain size, deformation temperature and strain-rate. The characteristic DRX features such as single to multiple peak stress transitions and convergence towards a steady-state stress and grain size are quantitatively reproduced by the model.

Objective: Flow abnormalities which occur in AF patient due to irregular heart rate which resultant turbulent flow both in left atrium and systemically may lead to endothelial dysfunction. The purpose is to detect endothelial dysfunction in non rheumatic AF patient. And test the hypothesis that endothelial dysfunction is reversible upon restoration of normal sinus rhythm and correction of the blood flow dynamics. Method: Endothelium-dependent (flow-mediated dilation) vasodilator function of brachial artery was measured using high resolution ultrasound in 30 patients with persistent non rheumatic AF who were scheduled for elective electrical cardioversion and in 10 control subjects. In patients who remained in sinus rhythm after cardioversion, these measurements were repeated after one month and two months. Result: Compared with control subjects, patients showed lower FMD during AF (6.66Â ± 1.62% vs 14.29Â ± 2.93%, p < 0.001). In patients who remained in sinus rhythm, FMD increased at both one month (6.66Â ± 1.62% vs 10.71Â ± 2.81%, p < 0.001) and two months (6.66Â ± 1.62% vs 14.28Â ± 3.48%, p < 0.001). Conclusion: There is endothelial dysfunction associated with non rheumatic persistent AF patients which is reversible upon restoration of normal sinus rhythm and correction of blood flow dynamics.

Ferrite growth behavior in Fe-C-Mn alloys has been studied using controlled decarburization experiments. Two types of kinetic transition are considered. A first transition is proposed which involves a change from ParaEquibrium (PE) contact conditions at short times to Local-Equilibrium with Negligible Partitioning at longer times (LENP). This transition is attributed to the gradual build up of an alloying element spike due to the diffusion of Mn across the interface. The cross-interface mobility of Mn is estimated based on the experimental results. In some alloys, we observe a transition to extended PE states at high temperatures. A simple model which quantitatively describes the experimental observations over a range of composition and temperature is proposed. A key feature of this model is the introduction of an alloying element capacity of the moving ferrite/austenite interface, X*. The introduction of this quantity is purely guided by the experimental data and, at present, there is no physically based method for calculating it.

The comparative effectiveness of solute Nb and NbC particles at impeding grain boundary motion is treated theoretically. It is shown that, for a steel containing ~0.05 at% Nb (~0.1 wt%Nb), under typical recrystallization conditions, solute Nb is more effective in the ferrite, whereas in the austenite, depending on the exact recrystallization temperature, either solute Nb or NbC precipitates may be more effective.

The effect of low temperature recovery treatments on the recrystallization kinetics during subsequent high temperature annealing was investigated in three Al-2.5%Mg alloys with various Fe additions. Recovery treatments were carried out at 190oC for times ranging from 0.25 to 65 hrs. Recrystallization treatments were carried out at 280oC. The kinetics of recrystallization was followed using the techniques of hardness measurement, optical metallography and calorimetry.

Motor cortex repetitive transcranial magnetic stimulation (rTMS) was found to relieve chronic neuropathic pain, but the optimal parameters of stimulation remain to be determined, including the site of stimulation.

The kinetics and morphology of the grain boundary grooving of Zn bicrystals with 16° <1010> tilt GB by Sn(Zn) melt has been studied at 325°C in equilibrium conditions in vacuum. It is shown that grooving process is interface controlled at least on the first stage. Groove walls mobility is evaluated. Changing of GB grove shape from “faceted walls” corner for annealing time < 78 h to concave “Mullins type” groove for annealing time > 78 h at the same experimental temperature was observed for the first time.

A physically based model is used to analyze quantitatively, the relative contributions of solute Nb and strain-induced NbC precipitation to the retardation of static recrystallization during the interpass time. The model explicitly takes into account the time evolution of strain-induced precipitation and its interaction with recovery and recrystallization. It is thus possible to quantitatively model the recrystallization kinetics taking into account: i) the effect of solute drag on the boundary mobility, ii) the effect of particle pinning (Zener drag) on the driving force for boundary motion, and iii) the effect of dislocation pinning by strain-induced precipitates, on the recovery kinetics and the nucleation of recrystallization. The analysis shows that there is an optimum partitioning of Nb between matrix solute and strain induced precipitates. This optimum partitioning maximizes particle pinning while ensuring an adequate solute drag effect to prevent the boundary from breaking away from solute atmosphere. The optimum partitioning of Nb between the matrix and the precipitates is shown to depend upon the temperature window of rolling, pass reduction and interpass time. The effect of delaying the kinetics of strain-induced precipitation of NbC through large Mn addition is shown to be an advantage for ensuring adequate solute drag in the low temperature, large pass deformation schedule used in near-net shape processing of thin slab or thick strip castings.

Catecholamines have complex effects on cardiac myocyte growth and survival, including the triggering of apoptosis at high concentration. Here, we examined whether at a lower concentration, catecholamine protected adult rat ventricular myocytes from apoptosis in vitro. Myocytes were exposed to staurosporine (ST, 10 microM) for 18 h, with or without epinephrine (0.1 or 10 microM) or fetal calf serum (10%). Apoptosis was assessed after 48 h of culture in terms of DNA fragmentation (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method, DNA gel electrophoresis). Epinephrine (0.1 microM) and serum reduced ST-induced myocyte apoptosis by approximately 50% (n = 12 cultures, P <.001), whereas epinephrine and serum alone did not influence the low apoptotic rate in control cultures. In contrast, 10 microM epinephrine induced marked apoptosis in ST-free conditions. The protective effects of 0.1 microM epinephrine and serum were blunted by the tyrosine kinase inhibitor genistein (n = 12 cultures, P <. 001). Extracellular signal-regulated kinase (ERK) activity was stimulated by 0.1 microM epinephrine but not by 10 microM epinephrine. Furthermore, the protective effect of epinephrine was mimicked by isoproterenol (1 microM) and forskolin (1 microM) but not by phenylephrine (10 microM) and was blunted by propranolol (10 microM) but not by prazozin (10 microM). Finally, isoproterenol and forskolin activated ERK, an effect that was blunted by propranolol. In conclusion, low epinephrine concentrations attenuate ST-induced apoptosis of adult cardiac myocytes in vitro, an effect mediated by coupling between the cAMP pathway and ERK activation. This suggests that a minimal adrenergic tone is essential for myocyte survival in conditions of unusual stress.

1. Species differences in the activity of the exchanger were evaluated in isolated myocytes from rat, guinea‐pig, hamster ventricles and human atria. Fluorescence measurements using fura‐2 were carried out in conjunction with the whole‐cell patch‐clamp technique for simultaneous recording of membrane currents and intracellular Ca2+ concentration. 2. Ca2+ release from sarcoplasmic reticulum (SR) induced either by rapid application of caffeine or by Ca2+ current elicited inward Na(+)‐Ca2+ exchange currents (INa‐Ca). The magnitude of INa‐Ca was largest in hamster, smallest in rat, with guinea‐pig and human myocytes having intermediate values. The ratio of caffeine‐induced exchanger current densities, normalized with respect to the peak Ca2+ release, was 4:2:1.5:1 for hamster > guinea‐pig > or = human > or = rat myocytes. 3. The rates of Ca2+ removal in the presence of caffeine, which reflect primarily the Ca2+ extruding activity of the Na(+)‐Ca2+ exchanger, followed the same order of hamster > guinea‐pig > or = human > or = rat. 4. The kinetics of INa‐Ca vs. Ca2+ transients were different among species. In rat myocytes, the kinetics of the INa‐Ca and the Ca2+ transients were similar, with INa‐Ca linearly proportional to intracellular Ca2+ concentration ([Ca2+]i). In hamster myocytes, the time course of INa‐Ca tracked only the declining phase of the Ca2+ transient with INa‐Ca having faster kinetics during the Ca2+ release. These findings suggest that the Ca2+ concentrations in the vicinity of the exchanger were significantly higher than those of the cytosol during Ca2+ release in hamster myocytes. 5. We concluded that there are significant species differences in the exchanger activity of cardiac myocytes, arising from differences in exchanger densities, their modulation and/or their spatial distribution with respect to the ryanodine receptors of cardiac myocytes.

Quinidine and flecainide, two class-I antiarrhythmics increase action potential duration (APD) at 90% repolarization and cellular refractory period in human atrial fibers without significant change in resting potential. On the other hand, quinidine decreases APD at 50%, whereas flecainide slightly increases, which suggests different effects on Ca2+ current. Using isolation cell procedure and whole cell recording, we found that 10 µM quinidine (34.77±6.5%, n=5) and 0.5 µM flecainide (50.46±6.2%, n=4) decrease calcium current in human atrium. It is concluded that, at therapeutical concentrations, quinidine and flecainide modify the action potential plateau phase in a different manner, which is not only related to the calcium current decrease.

The mechanical properties and precipitation behavior of hot-rolled microalloyed steels with varied Nb and V additions were investigated. The steels had a predominantly ferritic microstructure with a very good combination of strength (σUTS= 800-1000 MPa), ductility (total elongation = 16-19%) and hole expansion ratio (32-34%). The strength increased with increasing Nb and V content. The stretch-flangeability of the steels did not deteriorate with increasing strength. The favorable hole expansion behavior of the steels is attributed to the fine ferrite grain size (1.6-1.8 μm) and uniformity of the microstructure, as well as the fine precipitates of Nb and V carbonitrides in the matrix. Nb carbonitrides formed during hot rolling and contributed to the grain refinement through their interaction with recrystallization. The co-precipitation of Nb and V carbonitrides during coiling was confirmed and characterized by 3D atom probe tomography. The formation of these fine precipitates contributed to further increase in the strength of the V-containing steel allowing the steel to achieve strength > 1000 MPa.

The effect of low temperature recovery treatments on recrystallization kinetics during subsequent annealing was examined using a simple physically-based model. The results suggest that recovery may accelerate recrystallization in high stacking fault energy materials. Otherwise, recovery is expected to retard recrystallization by reducing the driving force for the nucleation and growth of recrystallized grains. These calculations help reconcile a number of apparently conflicting reports on the effect of recovery on recrystallization.