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OBJECTIVES To evaluate the efficacy of low-intensity focused ultrasound (LIFU) treatment on rapid relief of delayed-onset muscle soreness (DOMS) triggered by high-intensity exercise. METHODS A total of 16 healthy male college students were randomly divided into two groups: the LIFU group (n = 8) and the Sham group (n = 8). After the exercise protocol, the LIFU group received treatment, which parameters included that the power output was 2.5 W/cm2 , the frequency was 1 MHz, and the treating time was 20 minutes. The Sham group was treated with LIFU without energy output. Visual analog scale was used to evaluate the level of DOMS in every participant. The activities of plasma creatine kinase, lactate dehydrogenase, and the plasma concentration were measured by spectrophotometry. Tumor necrosis factor-α and interleukin-6 of serum were analyzed by enzyme-linked immunosorbent assay. RESULTS The visual analog scale of quadriceps femoris and/or calf muscles in the LIFU group decreased significantly at 24 hours (P

Compared with conventional casting process, laser direct metal deposition (LDMD) can effectively reduce component segregation in non-equiatomic high entropy alloys (HEAs). However, the non-equilibrium thermal history imparted by this method has a significant effect on the microstructure and mechanical properties of the HEA. The present work prepared non-equiatomic (FeNiCo)-(AlCrSiTi) HEAs using the LDMD process, after which some samples were subjected to a subsequent vacuum remelting (VRM) treatment. The variations in phase composition, microstructure and hardness between the HEAs processed using the LDMD or VRM methods were investigated. Differences in phase composition increased with increases in the proportion of the Al, Cr, Si and Ti components. Compared with the HEA samples processed using the VRM method, the LDMD specimens possessed much finer and simpler microstructures mainly comprising solid solution phases. At relatively high concentrations of the Al, Cr, Si and Ti components (32 at% and 40 at% in total), the HEAs processed under LDMD conditions had similar grain morphologies, intermetallic phases and microhardness values, while the VRM specimens presented completely different microstructures and properties.

Carbide coatings are frequently used to improve the wear resistance of industrial components in various wear environments. In this research, aiming at the service characteristics of easy wear and short service life of ball mill liners, WC–10Cr3C2–12Ni coatings were prepared by supersonic flame spraying technology (HVOF). The reciprocating sliding tests were conducted under four different WC particle size conditions, and the differences in the tribological behavior of the coatings and three–body abrasive wear mechanism were obtained. The findings reveal that the average nanohardness of the WC–Cr3C2–Ni coating is nearly five times greater than that of the steel substance. The COF of tribo-pairs decreases and then increases as the particle size increases. In the case of no particles, the surface of the coating is slightly worn, with fatigue and oxidative wear being the primary wear mechanisms. Small particles (1.5 μm and 4 μm) are crushed and coated on the coating surface, in which the extremely fine particles are plasticized to form friction layers that have a protective effect on the coatings. The protective effect of the particles disappears as the particle size increases and is replaced by a powerful chiseling effect on the coatings, resulting in serious material loss. The particle size has a direct relationship with coating wear.

Increasing magnetically favorable //ND texture components is a key challenge in the preparation of high-efficiency non-oriented electrical steels. In this study, an Fe-1.3 wt% Si steel with strong Cube ({100} ) and Goss ({110} ) texture was successfully produced by novel twin-roll strip casting, cold rolling and annealing process. The microstructure and texture of the material was characterized by optical microscopy, electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). The origin and formation mechanism of texture are described from the perspective of deformation and recrystallization behavior of specifically oriented grains. It was observed that initial Cube rotated toward {013} -{110} besides rotation toward {001} -{001} during cold rolling. In addition, new Cube deformation bands were developed in the deformed {115} -{115} grains. Cube components were partly retained as large block, small band structure and crystallite after heavy cold rolling. The Cube deformation structures served as nucleation sites of new Cube grains. The shear band within {114} , {112} and {111} matrix also provided some Cube nuclei. Morphology change from near bar-shaped to equiaxed occurred during the growth of Cube and Goss grains. The formation of recrystallization texture is attributed to the oriented nucleation mechanism, and the orientation pinning and size effects that impacted the intensity of texture component. The low thickness of strip and coarse solidification microstructure with strong {100} texture are the decisive factors to obtain strong Cube and Goss texture in strip-cast non-oriented electrical steel.

Alcohols are reported to have superlubricity at low loads during sliding; however, their lubricity under high loads has rarely been reported. Meanwhile, the lubrication mechanism of alcohols under high loads is still not well understood. Here, we first report the lubricity of methanol under 98 N and 1450 rpm and demonstrate the formation of graphene and fullerene-like nanostructures induced by tribochemical reactions. Results show that the lubrication mechanism was mainly attributed to the friction-induced graphene under boundary lubrication condition. Besides that, the wear rate of a YG8 hard alloy ball mainly occurred at the run-in processes, and the friction-induced graphene effectively inhibited further wear after the run-in processes. The formation mechanism of graphene was well investigated, and the flash temperature rise and catalyst (WC, WO2, and WO3) were the major causes for the formation of graphene.

High-entropy alloys having excellent properties are particularly suitable for the application as the filler metals in welding. In the present study, multi-component mixed powders of FeCoCrNiMn and CrFeNi2.4Al0.6, based on a high-entropy design, as well as the comparative 316L stainless steel powders, were used as the filler metals, to achieve the dissimilar welding between 304 stainless steel and SMA490BW steel by laser deposition welding. By comparative analysis of the microstructure and mechanical properties of three types of joints, the feasibility and weld-ability of the filler metal powders based on a high-entropy design were studied. It was found that the melting of base metal (BM) and weld metal dilution had an impact on the set high-entropy component in the weld zone. And high-entropy structures were achieved in the weld zone by using the powders of CrFeNi2.4Al0.6. Compared to the BM of SMA490BW steel, three types of joints presented a higher notched tensile strength and had a better corrosion resistance. The joint welded using the powders of CrFeNi2.4Al0.6 had the lowest hardness value in the weld zone, in which the joint was fractured during the notched tensile tests. The other two joints fractured near the notch in the SMA490BW steel side. Transgranular fracture and a typical dimple fracture were observed in the fractured joints. In this work, multi-component mixed powders of FeCoCrNiMn and CrFeNi2.4Al0.6, based on a high-entropy design, were used as the filler metals to achieve the dissimilar welding of 304 stainless steel to SMA490BW steel by laser deposition welding. And a detailed investigation of microstructures and mechanical properties of those dissimilar joints was carried out to explore the feasibility and weld-ability of the filler metal powders based on a high-entropy design.

Multipass friction stir processing (FSP) can result in a homogeneous microstructure and significant improvement in mechanical properties of magnesium alloys. Few studies have concentrated on the surface properties of Mg–Zn–Zr alloy during multipass FSP. The aim of this study was to investigate the microstructure evolutions as well as the effects on the surface corrosion and wear resistance of ZK60 plates during multipass FSP. An interesting finding is that FSP can significantly refine the grains and improve the surface properties of ZK60 alloy. However, subsequent passes of FSP cannot further reduce the grain size in the stir zone, but they cause an increase in the grain size in the ZK60 alloy. In addition, the subsequent passes of FSP are not beneficial, but rather are, harmful to the corrosion resistance of ZK60 alloy. There is little positive effect on the improvement in the wear resistance of ZK60 plates.

A dual-gradient bainite steel matrix composite was fabricated by direct laser deposition (DLD) method. The decomposition of WC (reinforcements) during DLD is utilized to adjust the gradient microstructure of the composite. Both the matrix morphology and the reinforcement distribution present obvious gradient variation along the deposition direction. The microhardness and impact toughness exhibit the opposite tendency from the bottom to top of the composite, which shows a good agreement with the gradient microstructure. The surface microhardness and impact toughness of the dual-gradient composite are 510 HV and 75 J/cm2, respectively. The hardness and toughness combination of the composite is superior to most steels for railway frog. The dual-gradient composite has great potential in improving the performance of railway frog.

Polymer brushes have been demonstrated as versatile and effective surface modification method to achieve unparalleled control over surface properties and functionality. Here, this review mainly highlights the intriguing performance and functionalities of zwitterionic polymer brushes with anti-polyelectrolyte property for a variety of applications in protein resistance, antibacterial activity, surface wetting, and surface frication. Different from other hydrophilic polymer brushes, zwitterionic brushes exhibit the unique zwitterionic-induced anti-polyelectrolyte effect, allowing for the development of new smart polymers and polymer-coated surfaces.

A novel microencapsulated phase change material (paraffin@SiO2/FeOOH) was prepared by an interfacial polycondensation method. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) results revealed that the microcapsules were regular spherical with a diameter of 2 ∼ 5 µm. The DSC analysis results showed that the melting point and latent heat of the paraffin@SiO2/FeOOH microcapsules were 26.10 °C and 104.44 J/g, encapsulation rate of the paraffin@SiO2/FeOOH microcapsules was 49.68%. As the TGA and photo-thermal performance measurements showed, inorganic shell material not only effectively improves thermal stability of phase change microcapsules, but also exhibited a certainly photo-thermal conversion property. Additionally, the experimental results of photocatalytic degradation of MB (Methylene blue) showed that paraffin@SiO2/FeOOH microcapsules have high photocatalytic activity against organic dyes under natural light. The developed materials can be applied to the fields of residential building temperature adjustment materials and the degradation of organic pollutants.

Table S4. Questionnaire results from participants in town/city areas. (DOCX 15 kb)

Table S3. Questionnaire results from participants in rural areas. (DOCX 15 kb)

Table S2. Prevalence of intestinal parasite infection in rural and urban sites according to different demographic and socioeconomic factors. (DOCX 16 kb)

Table S1. Prevalence of intestinal parasitic diseases in humans over time. (DOCX 14 kb)

Surface friction is a very important property for biomaterials, especially for those with implantation purposes. Recently, a new hydrophilic polymer, namely, poly(N-hydroxyethyl acrylamide) (PHEAA) has shown significant potential as biocompatible material. Herein, the surface friction of PHEAA brushes was studied. First, PHEAA brushes with well-controlled thickness were prepared via surface-initiated atomic transfer radical polymerization (SI-ATRP). Then, the surface friction coefficients of these brushes in water were measured aiming to better understand the thickness dependence of the surface lubrication properties. The results showed that the surface lubrication of PHEAA brushes highly depends on surface morphology and hydration state. With an optimal polymer film thickness of ∼21.5 nm, PHEAA-grafted surfaces show an ultralow friction coefficient of ∼0.013. To enhance the load bearing and wear resistance of the surface lubrication, a strategy of cross-linking was proposed. Cross-linked gel brushes were prepared by adding cross-linker N,N′-methylene bis(acrylamide) during the SI-ATRP. It was shown that the presence of a cross-linker in the ATRP resulted in high surface roughness, leading to a significant increment of surface friction to ∼2, albeit the water contact angle was lower. However, the strategy of cross-linking showed great success in enhancing the load bearing and wear resistance of polymer brushes. Differing from uncross-linked polymer brushes, cross-linked gel brushes showed decreased friction coefficients when increasing the compression load. Moreover, the wear resistance of the polymer brushes was also improved, as evidenced by the fact that the friction coefficient of cross-linked gel brushes was stable at 2000 s, while the friction coefficient of uncross-linked brushes increased quickly (at ∼700 s).

Graduation design is an important teaching link at the stage of undergraduate education to cultivate engineering college students' practical ability, innovation ability and engineer quality. Taking the questionnaire result of the graduation design of university students as the main foundation, this paper analyzes the problems in the topic selection for the graduation design of science subject and advances some corresponding suggestions. The main principles of graduated project topic selection are as follows: the title should not only meet the requirement of graduation and specialty training goal, it also covers the main course and professional knowledge system; it better to improve the proportion of topic selection for design to meet the professional standards of engineering education certification and cultivate students' ability to analyze and solve complex problems; the topics should be full of original, prospective and challenging insights; the topics should accord with university students' specialization interest and reinforce their employing competition.

Some polyzwitterionic brushes exhibit a strong "anti-polyelectrolyte effect" and ionic specificity that make them versatile platforms to build smart surfaces for many applications. However, the structure-property relationship of zwitterionic polymer brushes still remains to be elucidated. Herein, we aim to study the structure-dependent relationship between different zwitterionic polymers and the anti-polyelectrolyte effect. To this end, a series of polyzwitterionic brushes with different cationic moieties (e.g., imidazolium, ammonium, and pyridinium) in their monomeric units and with different carbon spacer lengths (e.g., CSL = 1, 3, and 4) between the cation and anion were designed and synthesized to form polymer brushes via the surface-initiated atom transfer radical polymerization. All zwitterionic brushes were carefully characterized for their surface morphologies, compositions, wettability, and film thicknesses by atomic force microscopy, contact angle measurement, and ellipsometry, respectively. The salt-responsiveness of all zwitterionic brushes to surface hydration and friction was further examined and compared both in water and in salt solutions with different salt concentrations and counterion types. The collective data showed that zwitterionic brushes with different cationic moieties and shorter CSLs in salt solution induced higher surface friction and lower surface hydration than those in water, exhibiting strong anti-polyelectrolyte effect salt-responsive behaviors. By tuning the CSLs, cationic moieties, and salt concentrations and types, the surface wettability can be changed from a highly hydrophobic surface (∼60°) to a highly hydrophilic surface (∼9°), while interfacial friction can be changed from ultrahigh friction (μ ≈ 4.5) to superior lubrication (μ ≈ 10

Friction stir welding (FSW) is a promising approach for the joining of magnesium alloys. Although many Mg alloys have been successfully joined by FSW, it is far from industrial applications due to the texture variation and low mechanical properties. This short review deals with the fundamental understanding of weak zones from the viewpoint of texture analysis in FSW Mg alloys, especially for butt welding. Firstly, a brief review of the microstructure and mechanical properties of FSW Mg alloys is presented. Secondly, microstructure and texture evolutions in weak zones are analyzed and discussed based on electron backscatter diffraction data and Schmid factors. Then, how to change the texture and strengthen the weak zones is also presented. Finally, the review concludes with some future challenges and research directions related to the texture in FSW Mg alloys. The purpose of the paper is to provide a basic understanding on the location of weak zones as well as the weak factors related to texture to improve the mechanical properties and promote the industrial applications of FSW Mg alloys.

As material for key parts applied in the aerospace field, the Cu-Be-Co-Ni alloy sustains cyclic plastic deformation in service, resulting in the low cycle fatigue (LCF) failure. The LCF behaviors are closely related to the precipitation states of the alloy, but the specific relevance is still unknown. To provide reasonable regulation of the LCF properties for various service conditions, the effect of precipitation states on the LCF behaviors of the alloy was investigated. It is found that the alloy composed fully of non-shearable &gamma, &prime, precipitates has higher fatigue crack initiation resistance, resulting in a longer fatigue life under LCF process with low total strain amplitude. The alloy with fine shearable &gamma, I precipitates presents higher fatigue crack propagation resistance, leading to a longer fatigue life under LCF process with high total strain amplitude. The cyclic stress response behavior of the alloy depends on the competition between the kinematic hardening and isotropic softening. The fine shearable &gamma, I precipitates retard the decrease of effective stress during cyclic loading, causing cyclic hardening of the alloy. The present work would help to design reasonable precipitation states of the alloy for various cyclic loading conditions to guarantee its safety in service.

Development of smart, multifunction materials is challenging but important for many fundamental and industrial applications. Here, we synthesized and characterized zwitterionic poly(3-(1-(4-vinylbenzyl)-1H-imidazol-3-ium-3-yl)propane-1-sulfonate) (polyVBIPS) brushes as ion-responsive smart surfaces via the surface-initiated atom transfer radical polymerization. PolyVBIPS brushes were carefully characterized for their surface morphologies, compositions, wettability, and film thicknesses by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), contact angle, and ellipsometer, respectively. Salt-responsive, switching properties of polyVBIPS brushes on surface hydration, friction, and antifouling properties were further examined and compared both in water and in salt solutions with different salt concentrations and counterion types. Collective data showed that polyVBIPS brushes exhibited reversible surface wettability switching between in water and saturated NaCl solution. PolyVBIPS brushes in water induced the larger protein absorption, higher surface friction, and lower surface hydration than those in salt solutions, exhibiting "anti-polyelectrolyte effect" salt responsive behaviors. At appropriate ionic conditions, polyVBIPs brushes were able to switch to superlow fouling surfaces (