Role of Metabolism in Bone Development and Homeostasis

Carbohydrates, fats, and proteins are the underlying energy sources for animals and are catabolized through specific biochemical cascades involving numerous enzymes. The catabolites and metabolites in these metabolic pathways are crucial for many cellular functions; therefore, an imbalance and/or dysregulation of these pathways causes cellular dysfunction, resulting in various metabolic diseases. Bone, a highly mineralized organ that serves as a skeleton of the body, undergoes continuous active turnover, which is required for the maintenance of healthy bony components through the deposition and resorption of bone matrix and minerals. This highly coordinated event is regulated throughout life by bone cells such as osteoblasts, osteoclasts, and osteocytes, and requires synchronized activities from different metabolic pathways. Here, we aim to provide a comprehensive review of the cellular metabolism involved in bone development and homeostasis, as revealed by mouse genetic studies.     

Threshold and growth mechanism of fatigue cracks under mode II and III loadings

ABSTRACT The fatigue crack growth behaviour of 0.47% carbon steel was studied under mode II and III loadings. Mode II fatigue crack growth tests were carried out using specially designed double cantilever (DC) type specimens in order to measure the mode II threshold stress intensity factor range, ΔK_IIth. The relationship ΔK_IIth > ΔK_Ith caused crack branching from mode II to I after a crack reached the mode II threshold. Torsion fatigue tests on circumferentially cracked specimens were carried out to study the mechanisms of both mode III crack growth and of the formation of the factory‐roof crack surface morphology. A change in microstructure occurred at a crack tip during crack growth in both mode II and mode III shear cracks. It is presumed that the crack growth mechanisms in mode II and in mode III are essentially the same. Detailed fractographic investigation showed that factory‐roofs were formed by crack branching into mode I. Crack branching started from small semi‐elliptical cracks nucleated by shear at the tip of the original circumferential crack.     

InxGa1−xAs ohmic contacts to n-type GaAs with a tungsten nitride barrier

Significant reduction of the contact resistance of In_0.7Ga_0.3As/Ni/W contacts (which were previously developed by sputtering in our laboratory) was achieved by depositing a W₂N barrier layer between the Ni layer and W layer. The In_0.7Ga_0.3 As/Ni/W₂N/W contact prepared by the radio-frequency sputtering technique showed the lowest contact resistance of 0.2 Ωmm after annealing at 550°C for 10 s. This contact also provided a smooth surface, good reproducibility, and excellent thermal stability at 400°C. The polycrystalline W₂N layer was found to suppress the In diffusion to the contact surface, leading to improvement of the surface morphology and an increase in the total area of the In_xGa−As between metal and the GaAs substrate. These improvements are believed to reduce the contact resistance.     

Hot carrier magnetophonon spectroscopy of semiconductors in high magnetic fields up to 40 T

Hot carrier magnetophonon resonances of n-type Si, short channel InP and p-type InSb were investigated in pulsed high magnetic fields up to 40 T. Using a recently developed high resolution technique in pulsed high fields, many new features of the hot carrier-phonon interactions in high magnetic fields were found.     

EFFECTS OF VISCOSITY OF LIQUID FOODS ON PALATAL PRESSURE

The deglutition of non-Newtonian liquids introduced into the mouth was studied dynamically by measuring palatal pressure (P) with pressure transducers set at three locations on the palate. The value of P and the swallowing pressure (S) changed only from 100 to 200 g/cm² over the viscosity range 10⁻² to 10¹ Pa.s. The retaining time (T) and work (W), required for swallowing after the liquid entered the mouth, remained almost constant up to a critical value of 1.0 Pa.s. above which both T and W increased markedly. When the viscosity was low, all of the liquid was swallowed in one deglutition, up to 15 mL volume. Therefore, T was almost constant but S increased with the volume. When the viscosity was high, the liquid was swallowed in several smaller portions. When the volume was high, T increased and S was either constant or it decreased.     

纳米Pt膜的晶粒尺寸及其对热导率的影响

采用电子束-物理气相沉积法（EB-PVD）制备了6个厚度为15-62nm的铂薄膜，研究了纳米薄膜的晶粒尺寸及其对热导率的影响规律．当薄膜厚度小于30nm时，晶粒平均尺寸接近于薄膜的厚度；晶粒尺寸随着薄膜厚度的增加而增大并趋于定值；当薄膜厚度大于30nm时，晶粒尺寸约为20nm．受薄膜的表面和内部晶界的综合影响，铂纳米薄膜的热导率大大低于体材料的值，并且纳米薄膜的热导率随着薄膜厚度的增加而增大并趋于一个低于体材料热导率的值．     

He对低活性Fe-Cr-Mn(W,V)合金辐照产生点缺陷行为的影响

采用超高压电镜与离子加速器相连结的复合辐照装置，研究了注He对低活性Fe-Cr-Mn(W，V)合金辐照产生的点缺陷及二次缺陷行为的影响．实验结果表明：辐照初期形成的点缺陷与He相互作用，进而影响二次缺陷(位错、位错环和空洞)的形成；He明显促进位错密度增大和空洞核心形成，并导致空洞肿胀增加．对辐照产生的点缺陷与He相互作用的机理进行了理论分析。     

Fe-Cr-Mn奥氏体合金的辐照体胀与诱起晶界偏析行为的研究SCIEI

本文采用电子束辐照,研究了Fe-15Cr-xMn合金以及添加W,V合金的孔洞体胀和诱起晶界偏析行为,并对包含晶界在内的辐照区进行成分分析。结果表明,在Fe-Cr-Mn系合金中孔洞体胀孕育期可以被强烈抑制,晶界偏析也减少。特别是,合金中添加W,V效果更加明显。用Mn代替Ni,通常要发生体胀和相的不稳定性,由于反Kirkendall效应导致Ni和Mn的扩散行为不同,使Fe富集在尾闾处,局部地区形成铁素体,有利于减少体胀和晶界偏析。     

展望21世纪新技术革命中的传感器

在回顾了以往产业革命中传感器的作用 ,比较工程传感器与人的感官的异同点之后 ,阐述了预计将于 2 1世纪爆发的新产业革命中传感器的使命及发展趋势     

污水处理排放水对小流量河流水体生态的影响

针对日本国鬼怒河流域小流量河流,通过对河床上附着生物膜的组成、底栖生物、细菌活性分析和AGP试验,研究了污水厂二级处理排放水对小流量河流生态的影响.研究表明,当污水厂二级处理排放水占河流流量比例较大时(研究河流所占比例为35%),同样会引发河流富营养化和影响河流水体的生态.因此,从保护水环境及其生态考虑,有必要对污水进行深度处理.