Seeing is believing? When scanning electron microscopy (SEM) meets clinical dentistry: The replica technique.

In restorative dentistry, the in situ replication of intra‐oral situations, is based on a non‐invasive and non‐destructive scanning electron microscopy (SEM) evaluation method. The technique is suitable for investigation restorative materials and dental hard‐ and soft‐tissues, and its interfaces. Surface characteristics, integrity of interfaces (margins), or fracture analysis (chipping, cracks, etc.) with reliable resolution and under high magnification (from ×50 to ×5,000). Overall the current study aims to share detailed and reproducible information about the replica technique. Specific goals are: (a) to describe detailed each step involved in producing a replica of an intra‐oral situation, (b) to validate an integrated workflow based on a rational sequence from visual examination, to macrophotography and SEM analysis using the replica technique; (c) to present three clinical cases documented using the technique. A compilation of three clinical situations/cases were analyzed here by means the replica technique showing a wide range of possibilities that can be reached and explored with the described technique. This guidance document will contribute to a more accurate use of the replica technique and help researchers and clinicians to understand and identify issues related to restorative procedures under high magnification.     

Tetrahydroindoles as Multipurpose Screening Compounds and Novel Sirtuin Inhibitors

Indoles are privileged structures in medicinal and bioorganic chemistry that are particularly well suited to serve as platforms for diversity. Among many other therapeutic areas, the indole scaffold has been used to design aromatic compounds useful to interfere with enzymes engaged in the regulation of substrate acylation status, such as sirtuins. However, the planarity of the indole ring is not necessarily optimal for all target enzymes, especially when functionalization with aromatic side chains is required. Replacement of flat scaffolds by nonplanar molecular cores dominated by sp³ hybridization is a common strategy to avoid the disadvantages associated with poor solubility and high promiscuity, while covering less-well-explored areas of chemical space. Thus, we synthesized fragment-like tetrahydroindoles suitable for fragment-based drug discovery as well as a well-characterized small library intended as multipurpose screening compounds. For proof of principle, these compounds were screened against sirtuins 1–3, enzymes known to be addressable by indoles. We found that 2,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indole-3-carboxamides are potent and selective SIRT2 inhibitors. Compound 16 t displayed an IC₅₀ value of 0.98 μm and could serve as exquisite starting point for hit-to-lead profiling.     

Bond strength and adaptation of pulp capping materials to dentin

This study evaluated the shear bond strength (SBS) and internal marginal adaptation of pulp‐capping materials to dentin. Flat occlusal deep dentin surfaces were produced and randomly assigned to two groups (sound or artificial caries‐affected dentin). The specimens in each group were assigned to one of seven subgroups according to the materials used: Biodentine, Theracal LC, Ultra‐Blend plus, Calcimol LC, ApaCal ART, EQUIA Forte, and Ionoseal. Buildups (3‐mm inner diameter and 2‐mm deep) were made over the dentin surfaces. The bonded specimens were tested under shear forces at a crosshead speed of 0.8 mm/min and fracture modes were determined using a stereomicroscope at 25× magnification. The materials were applied to the pulp floor of prepared Class I cavities and then the cavities were restored with composite resin. Restored molar teeth were subjected to 5,000 thermocycles and sectioned in a bucco–lingual direction. Resin replicas were made to determine the adaptation at the pulp floor with scanning electron microscopy. Significant differences were determined among both bond strengths and gap formations of the materials. EQUIA Forte applied to both dentin substrates had a significantly higher SBS than the other materials. The bond strength of each material was not influenced by the dentin condition. Biodentine (3.03%), EQUIA Forte (7.83%), and Theracal LC (13.37%) had lower gap formations compared to other materials but were not significantly different from each other.     

一种用于岩石材料微裂纹观察的复型技术

介绍了一种用于岩石材料微裂纹观察的复型技术。这种半透明的试样表面复型可有效复制宽度大于0.2μm的微观裂纹以及矿物颗粒的微结构特征，并可方便地用于光学显微镜和扫描电镜下观察。它的最大特点是不仅能精确复制岩样的表面裂纹，同时还能提供足够多的信息以鉴别矿物颗粒。应用表明：对于岩石材料的微破裂研究，特别对于矿物颗粒的破坏行为与岩石破坏的关系研究，它是一种方便而有效的方法。     

Replica time integrators

This paper is concerned with the classical problem of wave propagation in discrete models of nonuniform spatial resolution. We develop a new class of Replica Time Integrators (RTIs) that permit the two‐way transmission of thermal phonons across mesh interfaces. This two‐way transmissibility is accomplished by representing the state of the coarse regions by means of replica ensembles, consisting of collections of identical copies of the coarse regions. In dimension d, RTIs afford an O(n^d) speed‐up factor in sequential mode, and O(n^{d + 1}) in parallel, over regions that are coarsened n‐fold. In this work, we restrict ourselves to the solution of the 3d continuous wave equation, for both linear and non‐linear materials. By a combination of phase‐error analysis and numerical testing, we show that RTIs are convergent and result in exact two‐way transmissibility at the Courant–Friedrichs–Lewy limit for any angle of incidence. In this limit, RTIs allow step waves and high‐frequency harmonics to cross mesh interfaces in both directions without internal reflections or appreciable loss or addition of energy. The possible connections of RTIs with discrete‐to‐continuum approaches and, in particular, with the transition between molecular dynamics and continuum thermodynamics are also pointed to by way of future outlook. Copyright © 2011 John Wiley & Sons, Ltd.     

APT和萃取复型研究压力容器模拟钢中富Cu团簇的析出

用原子探针层析技术(APT)和萃取复型方法研究了核反应堆压力容器模拟钢中富Cu原子团簇的析出.提高了Cu含量的压力容器模拟钢经过880℃水淬,再经过660℃/10 h调质处理,随后在370℃进行不同时间的时效处理,利用APT对时效4500 h的样品分析结果显示,样品中富Cu原子团簇的数量密度达到3.1×1023m-3....     

Fabrication of a Large‐Area Hierarchical Structure Array by Combining Replica Molding and Atmospheric Pressure Plasma Etching

A novel approach to produce a large‐area hierarchical structure array is presented. The method combines replica molding and atmospheric pressure plasma (APP) etching processes. Liquid blends consisting of siliconized silsesquioxane acrylate (Si‐SSQA), polyethylene glycol dimethacrylate (PEGDMA), and photoinitiator are used as roughness formable materials during APP etching. Microstructures composed of the Si‐SSQA/PEGDMA mixtures are fabricated by replica molding. Nanoroughness is realized on the microstructures by argon/oxygen (Ar/O₂) APP etching in air. The nano­roughness on molded microstructures is efficiently controlled by varying the weight ratio of Si‐SSQA to PEGDMA and the etching time. The hierarchical structures fabricated by combining replica molding and Ar/O₂ APP etching show superhydrophilicity with a long‐term stability, resulting in the formation of hydroxyl‐terminated silicon oxide layer with the reorientation limit. On the other hand, the hierarchical structures treated with a perfluorinated self‐assembled monolayer (SAM) show increased the water contact angles of up to 161° depending on the morphology of the hierarchical structures. The increment of water contact angles is consistent with increment of the nano‐/microroughness of hierarchical structures.     

具负载平衡之IPTV影音串流系统

影音媒体具高带宽及实时特性,因此影音串流系统的服务质量的提升端赖影音服务器的有效管理。在此提出一套Video replication及Access request distribution的算法,藉由将热门影音分散到各影音服务器以及影音存取的分散,以达到各影音服务器系统负载平衡的效果。在此比较了3个不同的算法的负载平衡的状况,经实例验证,提出的算法确能达到影音服务器负载平衡的效果,承载更多的系统服务要求。该系统构建在Smart-i TV的IPTV系统台,并讨论了实作的相关技术。     

网格副本选择策略算法的研究

副本管理是数据网格中一个重要的组成部分,良好的数据副本管理策略是提高数据网格服务质量(Qos)的一个重要方面,本文主要对副本管理策略中的副本选择策略进行了研究。数据副本的选择策略讨论的是在己知的多个数据副本中如何根据当时的网络状态选择一个最佳的数据副本。本文提出了基于遗传算法的副本选择策略,这种选择策略考虑了多个副本请求对应多个副本资源的最佳分配方案,利用遗传算法得到最佳的数据副本分配方案,使副本的选择策略更高效。     

聚丙烯装置生产中细粉过多原因分析及解决措施

本文分析了球形聚丙烯装置生产中细粉过多的原因，并提出相应的解决措施。