Ubiquitous crystals play an important role in our daily lives. Recent studies on the properties and formation of crystals have proven the attachment of particles ranging from ion pairs to well-crystallized nanocrystals for crystallization. Compared with the monomer-by-monomer (i.e., atoms, ions, or molecules) addition described in long-standing classical theories, so-called nonclassical crystallization pathways are more complex due to the influence of nonspecific interactions influenced by the variation in system free energy and reaction kinetics. In view of the fact that detailed insights into nonclassical crystallization pathways have broadened the scope of research across various disciplines such as geological events, biomineralization mechanisms, environmental remediation, and the development of functional materials, this paper reviews the current state of the art in nonclassical nucleation (the prenucleation clusters pathway, aggregation pathway, etc.) and growth pathways (oriented attachment and random attachment) based on several highlights. In addition, the observed specific phenomena on crystallization in the last 10 years as well as recent advancements and achievements on the synthesis of mesocrystals are also elucidated. With implications and perspectives of nonclassical crystallization research proposed in this paper, this review aims to summarize research advancements regarding crystallizing systems. Emphasis will be placed on novel insights into nonclassical crystallization of materials, which are expected to provide completely new perspectives on the underlying crystallization mechanisms.
Adenoid cystic carcinoma (ACC) is a common salivary gland malignancy characterized by slow but progressive clinical course, proclivity for hematogenous spread and perineural invasion (PNI) that exhibits inherent resistance to complete surgical resection, systemic chemotherapy and conventional radiotherapy. The molecular alterations that underlie its PNI are poorly characterized. We report the combined use of laser capture microdissection (LCM) and high-throughput cDNA microarray to monitor in vivo gene expression profile of salivary ACC and to correlate the profile with PNI. Consecutive section staining with hematoxylin & eosin was applied to 15 cancerous tissues, among which 6 were judged as PNI. Pure cancer cells adjacent to the nerve tracts from 6 cancerous tissues judged as PNI were laser captured, and pure cancer cells from the same 6 tumors distant from the nerve tracts were also procured. Total RNA was extracted, amplified and subjected to cDNA microarray-based expression analysis. The patterns of gene expression were verified by quantitative real-time PCR and immunohistochemistry. As to the result of 6 arrays, a total of 53 genes were identified as being 2-fold or more differentially expressed in PNI cancer cell group as compared to non-PNI cancer cell control. Out of the 53 genes found consistently differentially expressed, 38 were up-regulated and 15 down-regulated. The combined use of LCM and cDNA microarray analysis provides a powerful new approach to monitor the in vivo molecular events of PNI in salivary ACC. These identified novel genes deserve further investigations to elucidate their clinicopathological significance.carcinoma, adenoid cystic; perineural invasion; microarray; laser capture microdissection; gene expression
Design, modeling, and analysis of an intelligent flexible isolation system for attenuating low-frequency micro-vibration are presented. The isolator consists of a payload platform, a supporting platform and four folded-beams with surface-bonded macro-fiber composites (MFCs). To accurately analyze the system performance, a piezoelectric finite element (FE) model is built and validated by the modal analysis results derived from ANSYS. This paper presents an attempt to widen the low-frequency isolation range for the micro-vibration using a modal frequency shift approach. The transfer functions of the active isolation system with different feedback controls are derived based on an FE model, in which feedback signals can be absolute and relative accelerations, absolute and relative displacement, relative velocity, and mixed responses. According to the numerical results, the expected performance of low-frequency vibration isolation can be easily achieved, especially by a kind of mixed responses feedback method. The time-domain simulations also show that the proposed piezoelectric isolation system exhibits a good isolation performance, endowing them with great potential for the micro-vibration restrain in aerospace application.
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