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排序方式: 共有3001条查询结果,搜索用时 31 毫秒
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Kumi O. Kuroda Yuko Shiraishi Kazutaka Shinozuka 《Psychiatry and clinical neurosciences》2020,74(10):516-526
Behaviors comparable to human child maltreatment are observed widely among mammals, in which parental care is mandatory for offspring survival. This article first reviews the recent findings on the neurobiological mechanisms for nurturing (infant caregiving) behaviors in mammals. Then the major causes of attack/desertion toward infants (conspecific young) in nonhuman mammals are classified into five categories. Three of the categories are ‘adaptive’ in terms of reproductive fitness: (i) attack/desertion toward non‐offspring; (ii) attack/desertion toward biological offspring with low reproductive value; and (iii) attack/desertion toward biological offspring under unfavorable environments. The other two are nonadaptive failures of nurturing motivation, induced by: (iv) caregivers’ inexperience; or (v) dysfunction in caregivers’ brain mechanisms required for nurturing behavior. The proposed framework covering both adaptive and nonadaptive factors comprehensively classifies the varieties of mammalian infant maltreatment cases and will support the future development of tailored preventive measures for each human case. Also included are remarks that are relevant to interpretation of available animal data to humans: (1) any kind of child abuse/neglect is not justified in modern human societies, even if it is widely observed and regarded as adaptive in nonhuman animals from the viewpoint of evolutionary biology; (2) group‐level characteristics cannot be generalized to individuals; and (3) risk factors are neither deterministic nor irreversible. 相似文献
3.
Age-hardening characteristics in a dental low-gold alloy composed of 40.0 wt% Au-35.0 wt% Ag-7.9 wt% Pd-7.0 wt% Cu-5.0 wt% In-3.5 wt% Zn-1.5 wt% Sn, were investigated by means of the hardness test, XRD study, SEM observations and EPMA. The following results were obtained. The age-hardening was characterized by a precipitation of Cu-rich alpha2 phase in the a phase. The softening that occurred following prolonged ageing was due to the heterogeneous formation of the fine nodular precipitates composed of the Ag-rich alpha1 phase and the Cu-rich alpha2 phase at the grain boundaries of the a phase. 相似文献
4.
Odatsu T Sawase T Kamada K Taira Y Shiraishi T Atsuta M 《Dental materials journal》2008,27(2):251-257
The purpose of this study was to investigate the effect of modifying aluminum oxide slips with magnesium oxide (MgO) to create a jointing material for In-Ceram Alumina. Jointed In-Ceram Alumina bars with In-Ceram Alumina slips containing 0-1.0 mass% MgO were examined by a three-point bending test. Joint-free bars were also tested as controls. Fracture surfaces were evaluated by scanning electron microscopy. In addition, linear shrinkage and fracture toughness were assessed. The 0.3 mass% MgO group showed the highest flexural strength among the jointed groups, and there were no statistical differences between the joint-free control groups. The fracture surface of 0.3 mass% MgO group showed increased sintering densification with reduced micropore size. No linear shrinkage was observed with the addition of MgO to the alumina slip. Added MgO was also effective in boosting fracture toughness. The present findings indicate that the MgO-supplemented binding material is useful for clinical applications. 相似文献
5.
Yumiko Hosoya Takanobu Shiraishi Maki Oshiro Susumu Ando Masashi Miyazaki John M. Powers 《Journal of dentistry》2009
Objective
This study evaluated the effects of specular component mode of specular component excluded (SCE) and specular component included (SCI) on color changes of different filler type resin composites after aging of 1 week and 1 year.Methods
Resin composites and shades used in this study were submicron-filled Estelite Σ (Σ: Inc, A2, A3, B3, C2, OA2, OA3) and nanofilled Filtek Supreme XT (XT: Clear, A2E, A2B, A3B, C2B, A2D, A3D). Resin disks of 2 mm in thickness and final polish with 2400-grit silicon carbide paper were stored in 100% relative humidity. One-week and 1-year after curing, the colors of the composite disks were measured with a spectrophotometer in SCI and SCE modes.Results
For both 1-week and 1-year specimens, the values of L* with SCI were significantly higher than SCE for all shades of Σ and XT; however, a* and b* were depended on brands and shades. Comparing 1-week and 1-year values, ΔE*ab ranged 1.5 (A3 and B3)–2.9 (Inc) with SCI and 1.4 (A3)–2.9 (Inc) with SCE for Σ, and 1.1 (A3D)–7.1 (Clear) with SCI and 1.4 (A3D)–7.6 (Clear) with SCE for XT. The values of ΔE*ab with SCE were higher than those of SCI for all shades of XT; however, for Σ, the differences varied with shades.Conclusion
Specular component mode (SCE vs. SCI) significantly influenced L* values; however, the color differences affected by aging were dependent on brands and shades of the resin composites tested. 相似文献6.
Duncan J Wood Takanobu Shiraishi Nobuya Shinozaki Richard van Noort 《Dental materials》2008,24(12):1661-1669
OBJECTIVE: The study was conducted to observe the spectral reflectance curves, and evaluate the color coordinates (CIELAB) of VM7 dentin ceramics (VITA, Germany) across the whole 3D-MASTER shade system. METHODS: Three disc samples, 13 mm in diameter and 1.4mm in thickness, were produced for each shade by firing following the manufacturer's instructions. Each fired disc was ground to a thickness of 1.0 mm and both faces were polished. Spectral reflectance data in the visible spectrum under the standard illuminant D65 were collected at 1 nm intervals by using a computer-controlled spectrophotometer. Color coordinates, L*, a*, b*, C*, h, in the three-dimensional CIELAB color space were obtained. RESULTS: (1) Spectral reflectance in the short-wavelength range systematically decreased with increasing chroma number (M1, M2, and M3) when compared within the same value (lightness) group (1M, 2M, 3M, 4M, and 5M). (2) Spectral reflectance decreased systematically across the whole visible spectrum with increasing value group when compared within the same chroma group. (3) A negative relationship was recognized between lightness (L*) and chromaticity index a* (red-green direction). That is, a* coordinate increases from approximately 1 for the 1M1 sample to approximately 13 for the 5M3 sample, the corresponding lightness systematically decreased from 87 to 69. (4) With increasing a* coordinate, hue angle (h) significantly decreased from 85 degrees for the 1M1 sample to 69 degrees for the 5M3 sample. (5) Lightness apparently increased with increasing hue angle (h) throughout the whole range of the 3D-MASTER shade system. (6) A strong positive relationship between chroma (C*) and chromaticity index b* (yellow-blue direction) was found, demonstrating that the chroma of the present ceramic is mainly controlled by the b* coordinate. SIGNIFICANCE: Systematic variations in spectral reflectance and color coordinates of VM7 dentin were observed throughout the 3D-MASTER shade system and were suggested to be caused by the fine structure of the sample which can interfere with shorter wavelengths in the visible spectrum. 相似文献
7.
Objective
Application of acidulated phosphate fluoride (APF) gel has been reported to cause deterioration of resin composites. This study investigated the effects of APF gel application on surface roughness, gloss and colour of resin composites.Methods
A2-shade resin disks of 2 mm thickness polished with 180-grit and 3000-grit SiC papers were made with Estelite Σ Quick (EQ), Clearfil Majesty (CM) and Beautifil II (B2). Six disks were prepared for each group. APF gel was applied in a 3 mm thickness on the top surface of resin disks and left for 30 min followed by rinsing and ultrasonic washing. This procedure was repeated 4 times. The L*a*b* values, colour difference (ΔE*ab), opacity, surface gloss and roughness of specimens before and after APF application were compared. Data were analysed ANOVA and Fisher's PLSD test with α = 0.05.Results
For the 3000-grit polishing groups, the order of influence of APF gel application on colour of resin composites was CM > B2 > EQ. Both in the 180- and 3000-grit polishing groups, colour difference before and after APF gel application was hard to detect (CM and B2) or impossible to detect (EQ) by naked eye. On the other hand, for all the resin composites, the gloss was significantly decreased by APF gel application. APF gel appeared to cause deterioration and dissolution of resin composites used in this study.Significance
In this limited study, supra-nano spherical filled Estelite Σ Quick showed the least change on colour, gloss and surface roughness by APF gel application. 相似文献8.
9.
Maruyama Suguru Kawaguchi Yoshihiko Akaike Hidenori Shiraishi Kensuke Saito Ryo Shimizu Hiroki Furuya Shinji Hosomura Naohiro Amemiya Hidetake Kawaida Hiromichi Sudo Makoto Inoue Shingo Kono Hiroshi Ichikawa Daisuke 《World journal of surgery》2020,44(3):863-868
World Journal of Surgery - Gastric cancers located within the upper-third of the stomach (UGC), especially the esophagogastric junction GC (EGJGC), have distinct clinicopathological features due to... 相似文献
10.
Eiji Okamoto Tetsuya Yano Yusuke Inoue Yasuyuki Shiraishi Tomoyuki Yambe Yoshinori Mitamura 《Artificial organs》2020,44(10):1067-1072
In this study, we developed a trans-valve left ventricular assist device (LVAD) that unites a rear-impeller axial-flow blood pump (AFBP) and a polymer membrane valve placed at the aortic valve position. The diameter and length of the rear impeller AFBP was 12 and 63 mm, respectively. The polymer membrane valve was similar to the jelly-fish valve consisting of a valve leaflet made of silicone rubber (thickness 0.5 mm), valve ring (diameter: 25 mm), and valve spokes. The trans-valve LVAD was examined in a mock circulation. An implantable pulsatile flow (PF) VAD was connected to an atrial reservoir to simulate the left ventricle (LV), and the Hall valve was worn in the inflow port, and the trans-valve LVAD was placed in the outflow port as an outflow valve. When the motor rotational speed increased to 26 400 rpm, the mean aortic flow increased from 4.2 to 5.3 L/min, mean aortic pressure increased from 83.4 to 100 mm Hg, and mean motor current of the implantable PF VAD decreased from 1.18 to 0.94 A (unloading effect on LV −21%). The energy equivalent pressure increased from 85.2 to 102 mm Hg, and surplus hemodynamic energy (SHE) decreased by −15.4% from the baseline. In conclusion, the trans-valve LVAD has an advantage of preserving pulsatility without any complicated mechanism and is a novel and promising LV support device. 相似文献