Study on the Friction and Wear Properties of PEEK against Cortical Bone Tissue Under Different Lubricating Conditions

The tribological behavior between orthopedic implants and cortical bone is important but usually neglected. Poly(ether-ether-ketone) (PEEK) is a promising material for orthopedic applications. To further understand and improve the interfacial tribological properties between PEEK implant and host bone tissue, a PEEK-cortical bone tribo-pair is designed and fabricated. The frictional and wear performance of such tribo-pair is investigated under different lubricants, i.e., simulated body fluid (SBF), calf serum (CS), hyaluronic acid (HA), and mucin (MUC). The results suggest that MUC solution can be utilized as an artificial natural synovial fluid to improve the tribological properties of PEEK-based implants.     

Effect of SnO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> film on the bonding of titanium–porcelain

The SnO _x film was deposited on titanium by sol–gel dipping process. After drying at 80 °C for 5 h, the films were treated for 10 min at different temperature. A thin and coherent SnO _x film with small spherical pores obtained at 300 °C served as an effective oxygen diffusion barrier and improved titanium–porcelain adhesion. The SnO _x film changed the fracture mode of the titanium–porcelain system and improved the mechanical and chemical bonding between porcelain and titanium, resulted in the increased bonding strength of titanium–porcelain.     

Palladium-catalyzed sequential formation of C-C bonds: efficient assembly of 2-substituted and 2,3-disubstituted quinolines

A series of substituted quinolines was prepared from arylamines, aldehydes, and terminal olefins (see scheme). The palladium-catalyzed sequential formation of C-C bonds proceeds smoothly with both electron-deficient and electron-rich olefins. When acrylic acid is used as terminal olefin, decarboxylation occurs to provide 2-substituted quinolines.     

Diborane(4) compounds with bidentate diamino groups

The reaction between B(2)(NMe(2))(4) and 1,2-(NH(2))(2)-4-Bu(t)C(6)H(3) affords the diborane(4) compound 1,2-B(2){1,2-(NH)(2)-4-Bu(t)C(6)H(3)}(2) as the exclusive product whilst the reaction between rac-1,2-(NH(2))(2)C(6)H(10) and B(2)(NMe(2))(4) also affords only the 1,2-isomer, i.e. 1,2-B(2){1,2-(NH)(2)C(6)H(10)}(2), which is shown to be the more stable isomer by computational methods. The previously reported compounds 1,1-B(2){1,2-(NH)(2)C(6)H(4)}(2) and 1,2-B(2){1,2-(NH)(2)C(6)H(4)}(2) both react with four equivalents of Bu(n)Li to give what are presumed to be tetra-anions which react further with MeI, SnClMe(3) or SnClPh(3) to give the tetrasubstituted products 1,1-B(2){1,2-(NMe)(2)C(6)H(4)}(2), 1,1-B(2){1,2-(NSnMe(3))(2)C(6)H(4)}(2) and 1,2-B(2){1,2-(NSnPh(3))(2)C(6)H(4)}(2) respectively. The compound 1,1-B(2){1,8-(NH)(2)C(10)H(6)}(2) has also been prepared from the reaction between B(2)(NMe(2))(4) and 1,8-diaminonaphthalene. Lithiation and subsequent reaction with SnClMe(3), SnCl(2)Me(2) or SnCl(2)Ph(2) affords 1,1-B(2){1,8-(NSnMe(3))(2)C(10)H(6)}(2), 1,1-B(2){1,8-(N(2)-μ-SnMe(2))C(10)H(6)}(2) and 1,1-B(2){1,8-(N(2)-μ-SnPh(2))C(10)H(6)}(2) respectively. All new compounds have been characterised by X-ray crystallography.     

Recovery of the C ∞ jet from the boundary distance function

For a compact Riemannian manifold with boundary, we want to find the metric structure from knowledge of distances between boundary points. This is called the ??boundary rigidity problem??. If the boundary is not concave, which means locally not all shortest paths lie entirely in the boundary, then we are able to find the Taylor series of the metric tensor (C ^?? jet) at the boundary (see Lassas et?al. (Math Ann 325:767?C793, 2003), Uhlmann et?al. (Adv Appl Math 31:379?C387, 2003)). In this paper we give a new reconstruction procedure for the C ^?? jet at non-concave points on the boundary using the localized boundary distance function. A closely related problem is the ??lens rigidity problem??, which asks whether the lens data determine metric structure uniquely. Lens data include information of boundary distance function, the lengths of all geodesics, and the locations and directions where geodesics hit the boundary. We give the first examples that show that lens data cannot uniquely determine the C ^?? jet. The example include two manifolds with the same boundary and the same lens data, but different C ^?? jets. With some additional careful work, we can find examples with different C ¹ jets, which means the boundaries in the two lens-equivalent manifolds have different second fundamental forms.     

Updated Pharmacological Effects,Molecular Mechanisms,and Therapeutic Potential of Natural Product Geniposide

At present, the potential of natural products in new drug development has attracted more and more scientists’ attention, and natural products have become an important source for the treatment of various diseases or important lead compounds. Geniposide, as a novel iridoid glycoside compound, is an active natural product isolated from the herb Gardenia jasminoides Ellis (GJ) for the first time; it is also the main active component of GJ. Recent studies have found that geniposide has multiple pharmacological effects and biological activities, including hepatoprotective activity, an anti-osteoporosis effect, an antitumor effect, an anti-diabetic effect, ananti-myocardial dysfunction effect, a neuroprotective effect, and other protective effects. In this study, the latest research progress of the natural product geniposide is systematically described, and the pharmacological effects, pharmacokinetics, and toxicity of geniposide are also summarized and discussed comprehensively. We also emphasize the major pathways modulated by geniposide, offering new insights into the pharmacological effects of geniposide as a promising drug candidate for multiple disorders.     

花岗岩的动态力学性能、本构模型与状态方程研究

为研究强动载荷条件下花岗岩的动态力学性能、本构模型与状态方程,分别采用分离式霍普金森压杆和轻气炮系统进行了压杆试验和飞片撞击试验,以获得不同条件下花岗岩的动态力学参数。压杆试验结果表明,花岗岩在应变率为80~320 s^–1范围内呈现明显的应变率效应,其强度和应变率近似呈指数关系。飞片撞击试验表明,随着飞片速度的增大,冲击波传播速度呈现明显的三折线变化趋势,而试样的可压缩性则随着加载速度的提高先逐渐增强然后再次降低。最后,根据试验数据,给出了强动载荷条件下花岗岩的HJC（Holmquist–Johnson–Cook）本构模型、Gruneisen状态方程以及动态屈服强度参数。

     

声学覆盖层吸声系数的多通道逆滤波测量

提出了一种利用最小二乘求逆计算的声学覆盖层吸声系数多通道逆滤波测量方法.该方法通过估计电路信道及水声信道的信道响应,利用最小二乘实现多通道逆滤波算法,通过多路逆信号的同步发射在声学覆盖层处实现高分辨率主瓣、低旁瓣和时域窄脉宽的入射波聚焦,从而提高声学覆盖层低频吸声系数的测量精度。仿真验证了该方法在混响抑制和空时聚焦中的效果.在压力水罐中进行了频率为0.8~5 kHz条件下的钢板试样反射系数和透射系数的测量实验,通过与理论计算值对比,验证了该测量方法的有效性。论文提出的方法适用于非自由场环境下声学覆盖层吸声系数的测量,尤其适用于低频条件下吸声系数的测量。     

Recent Advances in Renal Clearable Inorganic Nanoparticles for Cancer Diagnosis

The rapid growth of inorganic nanoparticles provides numerous opportunities for cancer diagnosis. Due to their adjustable and diverse characteristics that are strongly dependent on the size, morphology, charge, and the nature of surface coatings, they are widely used in the field of oncology. However, inorganic nanomaterials are usually difficult to degrade and excrete within a short time, resulting in long-term in vivo retention and potential toxicity, which significantly hinders their translation into clinical practice. Therefore, the development of renal clearable inorganic nanomaterials that can excrete out of body within desired timeframe is of great significance to promote their clinical bioapplications. Herein, the recent advances in renal clearable inorganic nanoparticles for tumor diagnosis are focused on, and the factors affecting the renal clearance efficiency, with a view to understand the underlying metabolism mechanism and the relevant bioapplications, are discussed.     

Accelerating Gas Escape in Anion Exchange Membrane Water Electrolysis by Gas Diffusion Layers with Hierarchical Grid Gradients

At high current densities, gas bubble escape is the critical factor affecting the mass transport and performance of the electrolyzer. For tight assembly water electrolysis technologies, the gas diffusion layer (GDL) between the catalyst layer (CL) and the flow field plate plays a critical role in gas bubble removal. Herein, we demonstrate that the electrolyzer's mass transport and performance can be significantly improved by simply manipulating the structure of the GDL. Combined with 3D printing technology, ordered nickel GDLs with straight-through pores and adjustable grid sizes are systematically studied. Using an in situ high-speed camera, the gas bubble releasing size and resident time have been observed and analyzed upon the change of the GDL architecture. The results show that a suitable grid size of the GDL can significantly accelerate mass transport by reducing the gas bubble size and the bubble resident time. An adhesive force measurement has further revealed the underlying mechanism. We then proposed and fabricated a novel hierarchical GDL, reaching a current density of 2 A/cm² at a cell voltage of 1.95 V and 80 °C, one of the highest single-cell performances in pure-water-fed anion exchange membrane water electrolysis (AEMWE).