Although three-dimensional (3D) bioprinting technology has gained much attention in the field of tissue engineering, there are still several significant engineering challenges to overcome, including ...lack of bioink with biocompatibility and printability. Here, we show a bioink created from silk fibroin (SF) for digital light processing (DLP) 3D bioprinting in tissue engineering applications. The SF-based bioink (Sil-MA) was produced by a methacrylation process using glycidyl methacrylate (GMA) during the fabrication of SF solution. The mechanical and rheological properties of Sil-MA hydrogel proved to be outstanding in experimental testing and can be modulated by varying the Sil-MA contents. This Sil-MA bioink allowed us to build highly complex organ structures, including the heart, vessel, brain, trachea and ear with excellent structural stability and reliable biocompatibility. Sil-MA bioink is well-suited for use in DLP printing process and could be applied to tissue and organ engineering depending on the specific biological requirements.
Wearable technologies are driving current research efforts to self‐powered electronics, for which novel high‐performance materials such as graphene and low‐cost fabrication processes are highly ...sought.The integration of high‐quality graphene films obtained from scalable water processing approaches in emerging applications for flexible and wearable electronics is demonstrated. A novel method for the assembly of shear exfoliated graphene in water, comprising a direct transfer process assisted by evaporation of isopropyl alcohol is developed. It is shown that graphene films can be easily transferred to any target substrate such as paper, flexible polymeric sheets and fibers, glass, and Si substrates. By combining graphene as the electrode and poly(dimethylsiloxane) as the active layer, a flexible and semi‐transparent triboelectric nanogenerator (TENG) is demonstrated for harvesting energy. The results constitute a new step toward the realization of energy harvesting devices that could be integrated with a wide range of wearable and flexible technologies, and opens new possibilities for the use of TENGs in many applications such as electronic skin and wearable electronics.
Shear‐exfoliated graphene integrated into a flexible and semitransparent triboelectric nanogenerator is developed by using a new facile isopropyl‐alcohol‐assisted direct transfer method. Environmentally and industrially preferred graphene solutions in water are obtained by shear exfoliation. Their graphene flakes are transferred onto any substrate, including poly(ethylene terephthalate), paper, fibers, glass, and SiO2/Si, driven by the transition of ispropyl alcohol liquid to vapor.
► Abrupt decrease of elongation in the intermediate temperatures is found in the superalloys. ► Microtwinning is a predominant deformation mechanism at intermediate temperature where the ductility ...minimum occurs. ► Deformation twins tend to form in the superalloys whose reduction of stacking fault energy is high.
The tensile behaviors of polycrystalline Ni-base superalloys have been studied in the temperature range of 25–980
°C. Anomalous increase of yield strength was observed in precipitation hardened superalloys at intermediate temperature. The alloy with high
γ′ volume fraction showed a remarkable increase of yield strength at intermediate temperature. A peak of yield strength was observed in the alloy with low
γ′ volume fraction at intermediate temperature while solid solution strengthened alloys did not have such peak. Abrupt decrease of ductility in the intermediate temperature regime was observed not only in the
γ′ strengthened superalloys but also in the solid solution strengthened superalloy. This result implies that
γ′ precipitation is not a substantial cause for the occurrence of the ductility minimum in the superalloys. It was found that twinning was an important deformation mechanism of the superalloys at intermediate temperature where ductility was abnormally low. Deformation twins formed easily in the superalloys whose reduction of stacking fault energy was high regardless of strengthening mechanisms because alloys with low stacking fault energy was prone to extend stacking faults.
► There was a significant decrease in OP TMF lives compared to LCF lives. ► OP TMF condition was found to accelerate surface crack initiation and propagation. ► The localized twins provided a ...preferential crack path during OP TMF cycling. ► LCF deformation appears to be more largely dependent on the diffusion. ► OP TMF deformation appears to be dominated by {1
1
1}〈1
1
2〉 partial dislocation movement.
The cyclic deformation and lifetime behaviors of a single crystal nickel-based superalloy CMSX-4 have been investigated under out-of-phase thermomechanical fatigue (OP TMF) and isothermal low cycle fatigue (LCF) conditions. OP TMF life exhibited less than a half of LCF life although smaller inelastic strain range and lower mean stress level during OP TMF were observed compared to those during LCF. During OP TMF cycling, the maximum tensile strain at the minimum temperature was found to accelerate the surface crack initiation and propagation. Additionally, the multiple groups of parallel twin plates near crack provided a preferential path for crack propagation.
Abstract. Purpose The purpose of this study was to investigate thoracic coupled motions of 20 Korean young individuals. Methods Thoracic motion of twenty healthy male college students aged 23.2+-3.1 ...was examined. The coupled motions of the thoracic regions T1-4, T4-8, T8-12 were measured using a three dimensional motion capture system. Results Coupled axial rotation in the same direction as lateral bending was observed in T1-T4 and T4-T8 in the neutral, flexed, and extended postures of the thoracic spine. In T8-T12, coupled axial rotation in the same direction as lateral bending were observed in the neutral and flexed postures, while coupled axial rotation in the opposite direction was observed in an extended posture. Conclusion The patterns of coupled motions in the thoracic spine demonstrated some variability between postures and regions in vivo. However, coupled motions in the same direction were predominantly lateral flexion or axial rotation in the three postures.
In order to evaluate the salinization in the western coastal area of South Korea, we performed a regional hydrochemical study on a total of 356 shallow groundwaters sampled within 10
km from the ...coastline. About 13, 5, and 37% of the samples exceed the drinking water standards for total dissolved solids, chloride, and nitrate, respectively, indicating significant deterioration and salinization of groundwaters. The concentrations of analyzed solutes are very wide in range, suggesting that the hydrochemistry is controlled by several intermixed processes such as seawater mixing, anthropogenic contamination, and water–rock interaction. Based on the interpretation of cumulative probability curves for Cl
− and NO
3
− concentrations, groundwaters are grouped into four types, as follows: (1) type 1 waters (37.6%) that are relatively poor in Cl
− and NO
3
−, which indicates little contamination due to seawater mixing and/or anthropogenic pollution; (2) type 2 waters (2.8%) enriched in Cl
−, indicating considerable effects of seawater mixing; (3) NO
3
−-rich, type 3 waters (58.1%) which show significant anthropogenic pollution; and (4) type 4 waters (1.4%) enriched in both Cl
− and NO
3
−, demonstrating the effects of both seawater mixing and anthropogenic contamination. The results of water-type classification are well confirmed by statistical analyses of hydrochemical data. As an effective tool for evaluating the relative degree of seawater mixing, we propose the ‘Seawater Mixing Index’ (SMI) based on the concentrations of Na, Mg, Cl, and SO
4. Most type 2 and type 4 waters have SMI values greater than 1. At least about 5 and 60% of well groundwaters are considered to be affected by salinization due to seawater mixing and anthropogenic contamination, respectively.
A one‐diode/one‐resistor structure, Pt/NiO/Pt/p‐NiOx/n‐TiOx/Pt, has been fabricated. This novel structure exhibits bistable resistance switching under forward bias, while the diode suppresses ...resistance switching in the Pt/NiO/Pt memory cell under reverse bias (see figure). Its low processing temperature and small cell size, as well as excellent rectifying characteristics, make this Pt/p‐NiOx/n‐TiOx/Pt diode structure a promising switch element for high‐ density, nonvolatile memory devices with 3D stack and cross‐point structures.
Mutations in TRPV4, a gene that encodes a Ca(2+) permeable non-selective cation channel, have recently been found in a spectrum of skeletal dysplasias that includes brachyolmia, spondylometaphyseal ...dysplasia, Kozlowski type (SMDK) and metatropic dysplasia (MD). Only a total of seven missense mutations were detected, however. The full spectrum of TRPV4 mutations and their phenotypes remained unclear.
To examine TRPV4 mutation spectrum and phenotype-genotype association, we searched for TRPV4 mutations by PCR-direct sequencing from genomic DNA in 22 MD and 20 SMDK probands.
TRPV4 mutations were found in all but one MD subject. In total, 19 different heterozygous mutations were identified in 41 subjects; two were recurrent and 17 were novel. In MD, a recurrent P799L mutation was identified in nine subjects, as well as 10 novel mutations including F471del, the first deletion mutation of TRPV4. In SMDK, a recurrent R594H mutation was identified in 12 subjects and seven novel mutations. An association between the position of mutations and the disease phenotype was also observed. Thus, P799 in exon 15 is a hot codon for MD mutations, as four different amino acid substitutions have been observed at this codon; while R594 in exon 11 is a hotspot for SMDK mutations.
The TRPV4 mutation spectrum in MD and SMDK, which showed genotype-phenotype correlation and potential functional significance of mutations that are non-randomly distributed over the gene, was presented in this study. The results would help diagnostic laboratories establish efficient screening strategies for genetic diagnosis of the TRPV4 dysplasia family diseases.
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