Metals by Micro‐Scale Additive Manufacturing: Comparison of Microstructure and Mechanical Properties

Many emerging applications in microscale engineering rely on the fabrication of 3D architectures in inorganic materials. Small‐scale additive manufacturing (AM) aspires to provide flexible and facile access to these geometries. Yet, the synthesis of device‐grade inorganic materials is still a key challenge toward the implementation of AM in microfabrication. Here, a comprehensive overview of the microstructural and mechanical properties of metals fabricated by most state‐of‐the‐art AM methods that offer a spatial resolution ≤10 μm is presented. Standardized sets of samples are studied by cross‐sectional electron microscopy, nanoindentation, and microcompression. It is shown that current microscale AM techniques synthesize metals with a wide range of microstructures and elastic and plastic properties, including materials of dense and crystalline microstructure with excellent mechanical properties that compare well to those of thin‐film nanocrystalline materials. The large variation in materials' performance can be related to the individual microstructure, which in turn is coupled to the various physico‐chemical principles exploited by the different printing methods. The study provides practical guidelines for users of small‐scale additive methods and establishes a baseline for the future optimization of the properties of printed metallic objects—a significant step toward the potential establishment of AM techniques in microfabrication.     

Segmentation and tracking of live cells in phase-contrast images using directional gradient vector flow for snakes

Cell shape is an important characteristic of the physiological state of a cell and is used as a primary read-out of cell behaviour in various assays. Automated accurate segmentation of cells in microscopy images is hence of large practical importance in cell biology. We report a simple algorithm for automated cell segmentation in high-magnification phase-contrast images, which takes advantage of the characteristic directionality of the local image intensity gradient at cellular boundaries due to the 'halo-effect'. We employ a two-step algorithm in which a gradient vector flow (GVF) field is first used to direct active contours to an approximate cell boundary. A directional GVF (DGVF) field is then calculated by considering only edges for which the image intensity gradient is directed outwards with respect to the approximate cell contour. Subsequently, the DGVF field is used to refine the cell contour, by directing active contours to edges with the desired gradient directionality. This method allows us to accurately segment cells in an image series, as well as follow the dynamics of cell shape over time in an automated fashion.     

Elevated expression levels of ANXA11, integrins β3 and α3, and TNF-α contribute to a candidate proteomic signature in urine for kidney allograft rejection

Purpose: Kidney transplantation is the treatment of choice for end stage renal disease, with long-term allograft loss being the major obstacle, and for which potential treatments are based on a histological diagnosis. The problem is that markers for predicting graft rejection are limited in number, are invasive, and are quite non-specific. We have hypothesized that protein biomarkers might be discovered in the urine of patients when acute or chronic rejection might be occurring. Experimental design: We have established a workflow in which initial screening for candidate biomarkers is first performed using urine samples on large-scale antibody microarrays. This approach generated several dozen candidates. The next step is to qualify some of the strongest signals using the high-throughput Reverse Capture Protein Microarray platform. Results: Four top candidates including ANXA11, Integrin α3, Integrin β3 and TNF-α, initially identified by the antibody microarray platform, were all qualified using Reverse Capture Protein Microarrays. We also used receiver operating condition (ROC) curves to independently quantify the specificity and sensitivity of these four analytes. Conclusions and clinical relevance: The present data suggest that these novel four analytes in the urine, together or independently, may contribute to a robust and quantitative urine proteomic signature for diagnosing acute or chronic rejection of renal allografts.     

Color coding of control room displays: the psychocartography of visual layering effects

OBJECTIVE: To evaluate which of three color coding methods (monochrome, maximally discriminable, and visual layering) used to code four types of control room display format (bars, tables, trend, mimic) was superior in two classes of task (search, compare). BACKGROUND: It has recently been shown that color coding of visual layers, as used in cartography, may be used to color code any type of information display, but this has yet to be fully evaluated. METHOD: Twenty-four people took part in a 2 (task) x 3 (coding method) x 4 (format) wholly repeated measures design. The dependent variables assessed were target location reaction time, error rates, workload, and subjective feedback. RESULTS: Overall, the visual layers coding method produced significantly faster reaction times than did the maximally discriminable and the monochrome methods for both the search and compare tasks. No significant difference in errors was observed between conditions for either task type. Significantly less perceived workload was experienced with the visual layers coding method, which was also rated more highly than the other coding methods on a 14-item visual display quality questionnaire. CONCLUSION: The visual layers coding method is superior to other color coding methods for control room displays when the method supports the user's task. APPLICATION: The visual layers color coding method has wide applicability to the design of all complex information displays utilizing color coding, from the most maplike (e.g., air traffic control) to the most abstract (e.g., abstracted ecological display).     

Transverse resolution improvement using rotating-grating time-multiplexing approach

The ability to improve the limited resolving power of optical imaging systems while approaching the theoretical diffraction limit has been an attractive discipline with growing interest over the last years due to its benefits in many applied optics systems. This paper presents a new approach to achieve transverse superresolution in far-field imaging systems, with direct application in both digital microscopy and digital holographic microscopy. Theoretical analysis and computer simulations show the validity of the presented approach.     

Non-Coding RNAs in Normal B-Cell Development and in Mantle Cell Lymphoma: From Molecular Mechanism to Biomarker and Therapeutic Agent Potential

B-lymphocytes are essential for an efficient immune response against a variety of pathogens. A large fraction of hematologic malignancies are of B-cell origin, suggesting that the development and activation of B cells must be tightly regulated. In recent years, differentially expressed non-coding RNAs have been identified in mantle cell lymphoma (MCL) tumor samples as opposed to their naive, normal B-cell compartment. These aberrantly expressed molecules, specifically microRNAs (miRNAs), circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs), have a role in cellular growth and survival pathways in various biological models. Here, we provide an overview of current knowledge on the role of non-coding RNAs and their relevant targets in B-cell development, activation and malignant transformation, summarizing the current understanding of the role of aberrant expression of non-coding RNAs in MCL pathobiology with perspectives for clinical use.     

Feel the image: The role of emotions in the image-seeking process

Images are characterized by a complex system of attributes. One of the most elusive properties of an image is its emotiveness – the ability to trigger an emotional reaction in the viewer. Prior research has demonstrated that users react to image emotiveness, yet to date there is little theoretical understanding and scarce empirical evidence as to the role played by emotiveness in the image retrieval process. Our study aims to fill this gap and investigates how users perceive the emotional content of the image-seeking task; explicate this emotional content in search keywords; and react to image emotiveness in selecting relevant images. Using a multimethod approach that combines quantitative and qualitative analyses, we performed three experiments where participants searched for images, both within the predefined set of images and in an open Web environment. Our findings suggest that although seekers rarely explicate image emotiveness in search keywords, their decision to select relevant images is largely dependent on their perception of the emotional content of the task and images. We discuss implications for research on emotions in image retrieval, as well as practical implications for designers of search systems.     

Hetero-Bambusurils

Synthetic anion carriers are essential for studying natural ion transporters and channels and for useful applications, such as treatment of channelopathies, supramolecular architecture, anion sensing and catalysis. Driven by the hypothesis that replacement of oxygen atoms in bambusurils (BUs) by other heteroatoms could significantly modify their anion binding properties, we calculated their molecular electrostatic potential and found a general trend of anion-affinity: S>O>NH. We confirmed these predictions experimentally by synthesizing semithio- and semiaza-BUs and studying their binding and transport properties. Although all analogs are excellent anion binders, only semithio-bambus[6]uril is an effective transmembrane transporter capable of polarizing lipid membranes through selective anion uniport. Semiaza-BUs exhibit simultaneous accommodation of three anions, linearly positioned along the main symmetry axis, which is reminiscent of natural chloride channels in E. coli.