A flexible, hydrophobic, and multilayered poly(vinyl alcohol) (PVA) film evolved to replace a commercially available nonbiodegradable easy seal-paper (ES-PAPER) sealing film. First, environmentally ...friendly fillers, such as cellulose nanocrystals (CNCs) or cellulose nanofibers (CNFs), were added to produce PVA + CNC/CNF composites via blade coating and solution casting to strengthen the mechanical properties of PVA. Subsequently, biodegradable and hydrophobic materials, such as poly(ethylene glycol)–poly(lactic acid) (PEG–PLA) and neat PLA, were added to prepare multilayered PEG–PLA and PLA hydrophobic composites using double-sided solution casting. The hydrophobicity of PVA was enhanced through heat treatment. Finally, the mechanical properties of the as-prepared PVA film were compared with those of a commercially available ES-PAPER sealing film. PVA + CNC/CNF composites exhibit excellent transparency and mechanical properties, whereas PVA + CNCs 3.0 wt% have the highest Young's modulus and tensile strength, which are, respectively, 3% and 96% higher than the Young's modulus and tensile strength of an ES-PAPER sealing film. With regard to strain at break, the prepared PVA film also exhibited a value many times larger than that of the ES-PAPER sealing film because of good filler dispersibility, which significantly enhanced the durability of the sealing film.
TiAl-based intermetallic alloys are prepared with Cu concentrations of 3–5 at.% (atomic ratio). The mechanical properties and microstructural characteristics of the alloys are investigated under ...static and dynamic loading conditions using a material testing system (MTS) and split-Hopkinson Pressure Bar (SHPB), respectively. The electrochemical properties of the various alloys are then tested in Ringer’s solution. It is shown that the level of Cu addition significantly affects both the flow stress and the ductility of the samples. For Cu contents of 3 and 4 at.%, respectively, the flow stress and strain rate sensitivity increase at higher strain rates. Furthermore, for a constant strain rate, a Cu content of 4 at.% leads to an increased fracture strain. However, for the sample with the highest Cu addition of 5 at.%, the flow stress and fracture strain both decrease. The X-ray diffraction (XRD) patterns and optical microscopy (OM) images reveal that the lower ductility is due to the formation of a greater quantity of γ phase in the binary TiAl alloy system. Among all the specimens, that with a Cu addition of 4 at.% has the best anti-corrosion performance. Overall, the results indicate that the favourable properties of the TiAlCu4 sample stem mainly from the low γ phase content of the microstructure and the high α2 phase content.
Ropeginterferon alfa-2b is a novel mono-pegylated proline-interferon. Its biweekly dosing schema has demonstrated tolerability and clinical efficacy for treating chronic hepatitis in previous ...clinical studies. This trial evaluates the pharmacokinetics of 400 μg ropeginterferon alfa-2b in patients with chronic hepatitis C virus (HCV) and provides the data to support the clinical utility of ropeginterferon alfa-2b at 400 μg.
Seventeen patients with chronic HCV genotype 2 were enrolled to receive a single injection of 400 μg ropeginterferon alfa-2b plus 14-day treatment of ribavirin. Pharmacokinetics, safety, and HCV RNA reduction/clearance were assessed.
Tmax was 154.003 h and T1/2 was 114.273 h. The Cmax was 29.823 ng mL−1. AUClast was 9364.292 h∗ng mL−1 and AUCinf was 11084.317 h∗ng mL−1. All adverse events were mild or moderate, and there were no serious adverse events. A 1000-fold reduction in the geometric mean of HCV RNA was observed 14 d after the single injection of ropeginterferon alfa-2b. Two patients achieved clearance of HCV RNA, and the other five patients had HCV RNA levels lower than 200 IU mL−1.
Ropeginterferon alfa-2b at 400 μg led to PK exposures associated with safety and notable clinical activity in patients with chronic HCV. This study suggests that ropeginterferon alfa-2b at 400 μg is an acceptable dosing regimen for treating chronic HCV and also provides supporting data for the clinical use of ropeginterferon alfa-2b at a higher starting dose for other indications.
A temperature sensor was fabricated with a functional conductive poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) coating on a long-period fiber grating (LPFG). The LPFG was ...fabricated by laser-assisted wet-chemical etching for controlling the grating depth of the LPFG after the treated surface of an optical fiber was inscribed by laser light. The functional conductive polymer acts as a temperature sustained sensing layer and enhances the grating depth of the LPFG sensor as a strain buffer at various temperatures. The sensor was subjected to three cycles of temperature measurement to investigate the sensor’s wavelength shift and energy loss when exposed to temperatures between 30 and 100 °C. Results showed that the sensor’s average wavelength sensitivity and its linearity were 0.052 nm/°C and 99%, respectively; average transmission sensitivity and linearity were 0.048 (dB/°C) and 95%, respectively.
The compressive mechanical behavior and fracture characteristics of FeAl intermetallic alloys containing 0–9 at.% Nb were investigated over a wide strain rate range of 10−3 s−1 to 5 × 103 s−1. For ...all of the alloys, the flow stress and strain rate sensitivity increased with increasing strain rate; however, the fracture strain decreased. The addition of Nb improved both the compressive strength and the ductility of the alloys. Among the various alloys, the alloy containing 6 at.% Nb showed the highest yield stress and fracture strain. The optical microscopy observations and X-ray diffraction results showed that the change in mechanical behavior of the various FeAl–Nb alloys was due mainly to differences in the precipitation of (Fe,Al)2Nb Laves phase. Moreover, a higher level of Nb addition prompted a change in the fracture morphology from a brittle fracture mode to a ductile fracture mode.
This work investigates the grinding process of a polycrystalline NiFeCo alloy through molecular dynamics (MD) simulation. The important factors that affect the grinding mechanics are cautiously ...investigated by analyzing the grinding force, resistance coefficient, local stress and strain, temperature, surface morphology, the evolution of structure and dislocation, which contain grinding velocity, machining depth, tool radius, and surface texture. The result shows that a higher machining velocity, greater grinding depth and tool radius lead to a larger grinding force and chipping volume, as well as a higher temperature of the substrate. While the grinding force, chipping volume, and temperature are the largest in the grinding of smooth surface compared to other surface textures due to the greater surface density. Moreover, the morphology of surface texture powerfully influences the pile-up volume, but slightly affects the shape of groove. The local shear strain and stress play a significant role in the grinding that explains the deformation mechanism in the substrate under the high pressure of cutting tool, and the grain boundary in polycrystalline is the control factor in the deformation behavior. Notably, the analysis of structure and dislocation evolution reveals that the nucleation and movement of dislocation caused plastic strain during the grinding show clearly the mechanism of subsurface damage. Besides, the dislocation motion is eliminated by grain boundary or interacts with each other to form new dislocation.
The figure shows the physical model (a) and surface morphology variation (b-e) of polycrystalline NiFeCo alloy under the grinding with different surface textures. Display omitted
•An increase in grinding parameters leads to greater grinding force, chipping volume, and workpiece temperature.•Grinding process characteristics are influenced by the different surface textures.•The grinding force, chipping volume, and temperature are the largest in the smooth surface grinding process.•The morphology of surface texture strongly affects the pile-up volume, but slightly influences the shape of groove.•The dislocation motion is prevented by the grain boundaries or interacts with each other to generate a new dislocation.
The purpose of this research is to shed more light on the intermixing and deformation of an Au nanoparticle during a deposition process on a Cu substrate by using molecular dynamics simulation. This ...study investigates the influence of surface conditions, incident angle, speed impact, and diameter of Au particle on the deformation behaviors, temperature, and the bonding between it and Cu substrate. The results reveal that after deposition, the high-stress zone, structure change, and dislocation mostly concentrate at the interfacial zone. The Au particle's deformation behaviors and dislocation evolutions closely relate to three stages, which are impacting, after impact, and relaxation stages. Moreover, the higher level of textured surface or the rougher surface generates a greater level of intermixing, flattening ratio, and bonding between the Au particle and Cu substrate. Decreasing the incident angle leads to an increase in the flattening ratio value and the Au–Cu bonding. While increasing the incident velocity from 100 to 700 m/s results in a greatly higher rate of deformation, Au–Cu bonding, and penetration depth. Interestingly, reducing the particle size helps to improve the rate of deformation.
Display omitted
●Deeper groove and rougher Cu surface lead to a higher level of intermixing, bonding Au particle/substrate.●The Au–Cu alloy formed at the interface zone and an amorphous structure in spray deposition process.●Textured surface and collision angle influence the evolution of dislocation structure.●The high-stress region mainly concentrates at an interface after the deposition process.●The temperature of Au particle increases during the impact stage.
Abstract
This study investigated the mechanical properties, glass-forming ability (GFA), and microstructural evolution of ZrCuAlNi amorphous alloys with various niobium (Nb) and silver (Ag) additions ...under static (1 × 10
–1
– 1 × 10
–3
s
−1
) and dynamic (3 × 10
3
– 5 × 10
3
s
−1
) loading conditions. The x-ray diffraction (XRD) results revealed that all of the alloys had an amorphous structure, and the GFA improved with an increasing Ag content. The Zr
56
Cu
24
Al
9
Ni
7
Nb
1
Ag
3
alloy showed the highest flow stress among the various alloys under both strain rate ranges. For all of the alloys, the fracture strain increased with an increasing Ag content. Moreover, the strain rate sensitivity increased with increasing strain rate. The scanning electron microscopy observations showed that the fracture surfaces had a dimple structure. As the Ag content increased, the dimple structure changed from a smooth to molten appearance. In addition, the dimple structure density increased with an increasing strain rate. The results present that the ductility of the ZrCuAlNi amorphous alloys could be improved by increasing the Ag element content.
Background & Aims Dual chronic infection with hepatitis C virus (HCV) and hepatitis B virus (HBV) is common in areas endemic for either virus. Combination therapy with ribavirin and pegylated ...interferon (peginterferon) is the standard of care for patients with HCV monoinfection. We investigated the effects of combination therapy in patients infected with both HBV and HCV (genotypes 1, 2, or 3). Methods The study included 321 Taiwanese patients with active HCV infection; 161 also tested positive for hepatitis B surface antigen (HBsAg) and 160 were HBsAg-negative (controls). Patients with HCV genotype 1 infection received peginterferon alfa-2a (180 μg) weekly for 48 weeks and ribavirin (1000–1200 mg) daily. Patients with HCV genotypes 2 or 3 received peginterferon alfa-2a weekly for 24 weeks and ribavirin (800 mg) daily. At 24 weeks posttreatment, patient samples were examined for a sustained virologic response (SVR) against HCV (serum HCV levels decreased to <25 IU/mL). Results In patients with HCV genotype 1 infection, the SVR was 72.2% in dually infected patients vs 77.3% in monoinfected patients after treatment. For patients with HCV genotype 2/3 infections, the SVR values were 82.8% and 84.0%, respectively, after treatment. Serum HBV DNA eventually appeared in 36.3% of 77 dual-infected patients with undetectable pretreatment levels of HBV DNA; this was not accompanied by significant hepatitis. Posttreatment HBsAg clearance was observed in 11.2% of 161 dual-infected patients. Conclusions Combination therapy with peginterferon alfa-2a and ribavirin is equally effective in patients with HCV monoinfection and in those with dual chronic HCV/HBV infection.
Cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) extracted from rice stalks were added to poly-methyl methacrylate (PMMA) with weight ratios of 0.1–1.0 wt%. The tribological and ...mechanical properties of the resulting composite materials were evaluated and compared. The addition of CNCs and CNFs reduced the wear volume by around 72–90% compared to pure PMMA samples in ball-on-disk wear tests performed against a chrome steel ball counter body. The CNC and CNF reinforcements also effectively improved flow stress under static and dynamic deformation conditions. Furthermore, the flow stress enhancement increased with an increasing CNC/CNF addition for both composite materials. For a constant strain and strain rate, the maximum enhancement effect was observed in the samples reinforced with CNFs. Overall, the CNF/PMMA showed a better tribological and mechanical performance than the CNC/PMMA. In addition, the CNFs had a longer length and higher aspect ratio than CNCs, which led to a more effective mechanical entanglement effect with the PMMA matrix. This physical entanglement improved the structural integrity of the composites. The CNC reinforcement (CNC percentage from 0% to 1.0 wt.%) also enhanced an effective improvement of about 35%∼45% in yield stress and ultimate strength under dynamic deformation conditions and static deformation conditions. Furthermore, the CNF reinforcement (CNF percentage from 0% to 1 wt%) also enhanced an effective improvement of about double yield stress and ultimate strength under dynamic deformation conditions and static deformation conditions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
PDF
