Control of strain relaxation behavior of Ge1−xSnx buffer layers

We have investigated how to realize a strain-relaxed Ge_1−xSn_x layer with large in-plane lattice constant as a buffer layer for a tensile-strained Ge layer. This paper reports the dependence of strain relaxation behavior in Ge_1−xSn_x layers on the misfit strain at the interface between Ge_1−xSn_x layers and substrates. We examined control of the misfit strain by growth of Ge_1−xSn_x layers on bulk-Si and virtual Ge substrates. Large misfit strain between the Ge_1−xSn_x layer and the Si substrate leads to strain relaxation during growth and high degree of strain relaxation after annealing. However, it also leads to interfacial mixing and surface roughening with annealing. As a result, the Ge_1−xSn_x layer having a Sn content of 9.2% was achieved, and it has a potential to induce a tensile strain of 0.99% in Ge layer.     

Reconfiguration management of remanufactured products for responding to varied user needs

In the face of worsening environmental problems, the manufacturing industry is required to reduce resource consumption and environmental loads during product life cycles while responding to diversified user needs without cost increases. In this paper, we propose a reconfiguration method to remanufacture a variety of products using modules extracted from returned products of multiple generations for responding to varied user needs. With this method, we can maximize the sales amount of remanufactured products, which meet the performance requirements of each user group. We demonstrate the effectiveness of the method by applying it to photocopiers.     

Understanding ferroelectric performances of spin-coated odd–odd nylon thin films

Ferroelectric properties of organic odd–odd nylon spin-coated thin films are investigated. Nylon 11-11, 9-13, and 11-13 are prepared by melt polymerization of the nylon salt consisting of the corresponding dicarboxylic acid and diamine. The obtained nylon is spin coated to obtain thin films with the thicknesses in the range of 85–108 nm. After spin coating, the sample films are subjected to several thermal history procedures, namely the films are either melt quenched or thermally annealed at various temperatures. The melt-quenched films are in the γ crystal phase that is directly related to the ferroelectricity of the sample thin films. Enhanced ferroelectricity is measured for the sample films that are thermally annealed at 165 °C. The remanent polarization is significantly affected by the crystallite size. Ferroelectric switching of the thin films is studied by applying a sinusoidal voltage with the frequencies of 1, 10, 100, 1 k, and 10 kHz. The switching speed is evaluated from the full width at half-maximum of the switching current. A switching speed of 4.7 × 10³ s⁻¹ (switching time of 210 μs) is measured for 1 kHz switching. The remanent polarization is strongly decreased by increasing the switching frequency, whereas the coercive field is increased. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47595.     

Ferroelectric switching in spin-coated nylons 11 and 12

Here, we investigate the correlation between the crystal structures and the ferroelectric switching by a sinusoidal alternative electric field for spin-coated nylon 11 films as an odd nylon and for nylon 12 as an even nylon. These spin-coated nylons afforded thin films with thicknesses ranging from 101 to 125 nm. The obtained thin films were subjected to melt-quenching, melt-cooling down, annealing-quenching, or annealing-cooling down. These processes were notably related to the resulting crystal structures. In particular, the crystal structures involving twisted bonds in the molecular chains were significantly related to ferroelectricity in both nylon 11 and nylon 12. Namely, the vector component of the amide dipole moments is transverse to the direction of the molecular chains, which is induced by the presence of more twisted bonds and is significantly related to the remanent polarization P_r for both nylons. In nylon 11, the hydrogen bonding interaction between the intermolecular amide dipole moments in the α and δ crystal forms was weakened by the existence of more twisted bonds. In nylon 12, the nonpolar γ crystal form was transformed to a polarizable γ’ crystal form because of the existence of more twisted bonds. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48438.     

A ROCK Inhibitor Promotes Graft Survival during Transplantation of iPS-Cell-Derived Retinal Cells

Currently, retinal pigment epithelium (RPE) transplantation includes sheet and single-cell transplantation, the latter of which includes cell death and may be highly immunogenic, and there are some issues to be improved in single-cell transplantation. Y-27632 is an inhibitor of Rho-associated protein kinase (ROCK), the downstream kinase of Rho. We herein investigated the effect of Y-27632 in vitro on retinal pigment epithelium derived from induced pluripotent stem cells (iPS-RPE cells), and also its effects in vivo on the transplantation of iPS-RPE cell suspensions. As a result, the addition of Y-27632 in vitro showed suppression of apoptosis, promotion of cell adhesion, and higher proliferation and pigmentation of iPS-RPE cells. Y-27632 also increased the viability of the transplant without showing obvious retinal toxicity in human iPS-RPE transplantation into monkey subretinal space in vivo. Therefore, it is possible that ROCK inhibitors can improve the engraftment of iPS-RPE cell suspensions after transplantation.     

Ge1−xSnx stressors for strained-Ge CMOS

A strong piezoresistive effect of GaAs micro-structure which is based on high electron mobility transistor (HEMT) is reported in this paper. The GaAs HEMT is embedded in the root of the cantilever as the sensitive element in order to detect the deformation. The strain is simulated with the ANSYS software, and the maximum gauge factor is about 26,350, which is nearly a hundred times larger than that of piezoresistive silicon. The high gauge factor is not only due to the option of voltage bias, but also the combination of the piezoresistive and piezoelectric effect. The obtained results demonstrate that GaAs micro-structure based on HEMT can be suitable for high sensitive stress/pressure sensors.     

Long Non-Coding RNA CRNDE Is Involved in Resistance to EGFR Tyrosine Kinase Inhibitor in EGFR-Mutant Lung Cancer via eIF4A3/MUC1/EGFR Signaling

(1) Background: Acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) is an intractable problem for many clinical oncologists. The mechanisms of resistance to EGFR-TKIs are complex. Long non-coding RNAs (lncRNAs) may play an important role in cancer development and metastasis. However, the biological process between lncRNAs and drug resistance to EGFR-mutated lung cancer remains largely unknown. (2) Methods: Osimertinib- and afatinib-resistant EGFR-mutated lung cancer cells were established using a stepwise method. A microarray analysis of non-coding and coding RNAs was performed using parental and resistant EGFR-mutant non-small cell lung cancer (NSCLC) cells and evaluated by bioinformatics analysis through medical-industrial collaboration. (3) Results: Colorectal neoplasia differentially expressed (CRNDE) and DiGeorge syndrome critical region gene 5 (DGCR5) lncRNAs were highly expressed in EGFR-TKI-resistant cells by microarray analysis. RNA-protein binding analysis revealed eukaryotic translation initiation factor 4A3 (eIF4A3) bound in an overlapping manner to CRNDE and DGCR5. The CRNDE downregulates the expression of eIF4A3, mucin 1 (MUC1), and phospho-EGFR. Inhibition of CRNDE activated the eIF4A3/MUC1/EGFR signaling pathway and apoptotic activity, and restored sensitivity to EGFR-TKIs. (4) Conclusions: The results showed that CRNDE is associated with the development of resistance to EGFR-TKIs. CRNDE may be a novel therapeutic target to conquer EGFR-mutant NSCLC.     

Loosening of Lipid Packing by Cell-Surface Recruitment of Amphiphilic Peptides by Coiled-Coil Tethering

Lipid packing has a strong influence on the formation and structural dynamics of cell membranes. Techniques to modulate lipid packing may thus enable modification of cellular functions and events. An 18-residue amphiphilic helical peptide derived from the N-terminal segment of epsin-1 (EpN18) is reported to induce positive membrane curvature and to loosen lipid packing in the cell membrane. In this study, it is shown that EpN18, crosslinked to a leucine-zipper peptide K4, is recruited to the cell surface by interacting with a cell-surface-expressed E3 leucine-zipper segment. Cell-surface tethering markedly enhanced loosening of lipid packing, which led to the promotion of membrane translocation of octaarginine. The loosening of lipid packing by EpN18 was also confirmed by analyzing the generalized polarization value with a membrane-environment-sensitive dye, 2-hydroxy-3-{2-[(2-hydroxyethyl)dimethylamino]ethyl}-4-{2-[6-(dibutylamino)-2-naphthyl]ethenyl}pyridiniumdibromide (di-4-ANEPPDHQ). This approach thus shows promise for the control of lipid packing and related cellular events.     

Preparation and characterization of pillared carbons obtained by pyrolysis of silylated graphite oxides

Pillared carbons were prepared by pyrolyzing various graphite oxides silylated by 3-aminopropylmethyldiethoxysilane. They were formed when silylated graphite oxides with silicon contents of 12.6% or higher were pyrolyzed in vacuo at 500-600 °C. Their interlayer spacings were 1.23-1.31 nm. When silylated graphite oxide was prepared at 90 °C, the reductive decomposition of graphite oxide by amino groups of 3-aminopropylmethyldiethoxysilane was suppressed and pillared carbon with higher crystallinity was obtained. At higher temperatures of pyrolysis, silylated graphite oxide decomposed to residual carbon without pillars. The pillars between the carbon layers contained methyl groups originating from the 3-aminopropylmethyldiethoxysilane. Based on the interlayer spacing and elemental analysis data, a structure model for the pillar is proposed. Pillared carbons showed type IV nitrogen adsorption isotherms and they contained both mesopores and a small volume of micropores. The BET surface area of the pillared carbon reached a maximum value of 236 m²/g, when it was prepared from graphite oxide silylated at 105 °C for 20 days.