Feature Reduction for Product Recommendation in Internet Shopping Malls

One of the widely used methods for product recommendation in Internet shopping malls is matching product features against customers’ profiles. In this method, it is very important to choose suitable set of features for recommendation efficiency and performance, which has, however, not been rigorously researched so far. In this paper, we build a data set collected from a virtual Internet shopping experiment and adapt and apply feature reduction techniques from pattern matching and information retrieval fields to the data to analyze recommendation performance. The analysis shows that the application of SVD (Singular Value Decomposition) can be the best among the applied methods for recommendation performance

Origin of High-Temperature Superconductivity in Compressed LaH10_{10}

Room-temperature superconductivity has been one of the most challenging subjects in modern physics. Recent experiments reported that lanthanum hydride LaH$_{10{\pm}x}$ ($x$$<$1) raises a superconducting transition temperature $T_{\rm c}$ up to ${\sim}$260 (or 215) K at high pressures around 190 (150) GPa. Here, based on first-principles calculations, we reveal the existence of topological Dirac-nodal-line (DNL) states in compressed LaH$_{10}$. Remarkably, the DNLs protected by the combined inversion and time-reversal symmetry and the rotation symmetry create a van Hove singularity (vHs) near the Fermi energy, giving rise to large electronic density of states. Contrasting with other La hydrides containing cationic La and anionic H atoms, LaH$_{10}$ shows a peculiar characteristic of electrical charges with anionic La and both cationic and anionic H species, caused by a strong hybridization of the La $f$ and H $s$ orbitals. We find that a large number of electronic states at the vHs are strongly coupled to the H-derived high-frequency phonon modes that are induced via the unusual, intricate bonding network of LaH$_{10}$, thereby yielding a high $T_{\rm c}$. Our findings not only elucidate the microscopic origin of the observed high-$T_{\rm c}$ BCS-type superconductivity in LaH$_{10}$, but also pave the route for achieving room-temperature topological superconductors in compressed hydrogen-rich compounds.Comment: 9 pages, 11 figure

Effect of Pre-Exercise Heat Pack Treatment on Markers of Muscle Damage After Resistance Exercise

Abstracts PURPOSE This study aimed to investigate the effect of pre-exercise heat pack treatment on muscle activity and markers of muscle damage after exercise-induced damage. METHODS Ten healthy male university students were tested for 3 weeks. They were exposed to three conditions (non-warm-up exercise, warm-up exercise, and heat pack treatment) before exercise. The experiment was conducted at 1-week intervals for every partici-pant. The warm-up exercise was performed by combining a modified active warm-up with a cycle ergometer and an isokinetic dynamometer. The main exercise, which modified the exercise-induced muscle damage protocol, was conducted by flexing and extending the knee joint using an isokinetic dynamometer. The heat pack treatment before the exercise involved moist heat application for 20 min. RESULTS The changes in blood muscle fatigue markers and blood muscle damage markers were not significantly different between the groups (α>.05). However, significant differences were observed in the time immediately after exercise, 10-min recovery, 30-min recovery, and 60-min recovery (p<.05). A statistically significant difference was observed in the change in pain in the heat pack treatment group (p<.05). CONCLUSIONS Heat pack treatment for 20 min before exercise did not minimize the muscle damage markers and fatigue markers following exercise-induced damage, but reduced immediate muscle soreness. Use of heat pack treatment was associated with a change in muscle activity and improvement in certain aspects of muscle soreness

SPIN90 Knockdown Attenuates the Formation and Movement of Endosomal Vesicles in the Early Stages of Epidermal Growth Factor Receptor Endocytosis

The finding that SPIN90 colocalizes with epidermal growth factor (EGF) in EEA1-positive endosomes prompted us to investigate the role of SPIN90 in endocytosis of the EGF receptor (EGFR). In the present study, we demonstrated that SPIN90 participates in the early stages of endocytosis, including vesicle formation and trafficking. Stable HeLa cells with knockdown of SPIN90 displayed significantly higher levels of surface EGFR than control cells. Analysis of the abundance and cellular distribution of EGFR via electron microscopy revealed that SPIN90 knockdown cells contain residual EGFR at cell membranes and fewer EGFR-containing endosomes, both features that reflect reduced endosome formation. The delayed early endosomal targeting capacity of SPIN90 knockdown cells led to increased EGFR stability, consistent with the observed accumulation of EGFR at the membrane. Small endosome sizes and reduced endosome formation in SPIN90 knockdown cells, observed using fluorescent confocal microscopy, strongly supported the involvement of SPIN90 in endocytosis of EGFR. Overexpression of SPIN90 variants, particularly the SH3, PRD, and CC (positions 643 - 722) domains, resulted in aberrant morphology of Rab5-positive endosomes (detected as small spots located near the cell membrane) and defects in endosomal movement. These findings clearly suggest that SPIN90 participates in the formation and movement of endosomes. Consistent with this, SPIN90 knockdown enhanced cell proliferation. The delay in EGFR endocytosis effectively increased the levels of endosomal EGFR, which triggered activation of ERK1/2 and cell proliferation via upregulation of cyclin D1. Collectively, our findings suggest that SPIN90 contributes to the formation and movement of endosomal vesicles, and modulates the stability of EGFR protein, which affects cell cycle progression via regulation of the activities of downstream proteins, such as ERK1/2, after EGF stimulation