Although three-dimensional (3D) bioprinting technology has gained much attention in the field of tissue engineering, there are still several significant engineering challenges to overcome, including ...lack of bioink with biocompatibility and printability. Here, we show a bioink created from silk fibroin (SF) for digital light processing (DLP) 3D bioprinting in tissue engineering applications. The SF-based bioink (Sil-MA) was produced by a methacrylation process using glycidyl methacrylate (GMA) during the fabrication of SF solution. The mechanical and rheological properties of Sil-MA hydrogel proved to be outstanding in experimental testing and can be modulated by varying the Sil-MA contents. This Sil-MA bioink allowed us to build highly complex organ structures, including the heart, vessel, brain, trachea and ear with excellent structural stability and reliable biocompatibility. Sil-MA bioink is well-suited for use in DLP printing process and could be applied to tissue and organ engineering depending on the specific biological requirements.
Abstract
Bacteria can utilize signal molecules to coordinate their behavior to survive in dynamic multispecies communities. Indole is widespread in the natural environment, as a variety of both ...Gram-positive and Gram-negative bacteria (to date, 85 species) produce large quantities of indole. Although it has been known for over 100 years that many bacteria produce indole, the real biological roles of this molecule are only now beginning to be unveiled. As an intercellular signal molecule, indole controls diverse aspects of bacterial physiology, such as spore formation, plasmid stability, drug resistance, biofilm formation, and virulence in indole-producing bacteria. In contrast, many non-indole-producing bacteria, plants and animals produce diverse oxygenases which may interfere with indole signaling. It appears indole plays an important role in bacterial physiology, ecological balance, and possibly human health. Here we discuss our current knowledge and perspectives on indole signaling.
Here we report a facile, prompt protocol based on deep-learning techniques to sort out intricate phase identification and quantification problems in complex multiphase inorganic compounds. We ...simulate plausible powder X-ray powder diffraction (XRD) patterns for 170 inorganic compounds in the Sr-Li-Al-O quaternary compositional pool, wherein promising LED phosphors have been recently discovered. Finally, 1,785,405 synthetic XRD patterns are prepared by combinatorically mixing the simulated powder XRD patterns of 170 inorganic compounds. Convolutional neural network (CNN) models are built and eventually trained using this large prepared dataset. The fully trained CNN model promptly and accurately identifies the constituent phases in complex multiphase inorganic compounds. Although the CNN is trained using the simulated XRD data, a test with real experimental XRD data returns an accuracy of nearly 100% for phase identification and 86% for three-step-phase-fraction quantification.
In recent years, demand has been increasing for target detection and tracking from aerial imagery via drones using onboard powered sensors and devices. We propose a very effective method for this ...application based on a deep learning framework. A state-of-the-art embedded hardware system empowers small flying robots to carry out the real-time onboard computation necessary for object tracking. Two types of embedded modules were developed: one was designed using a Jetson TX or AGX Xavier, and the other was based on an Intel Neural Compute Stick. These are suitable for real-time onboard computing power on small flying drones with limited space. A comparative analysis of current state-of-the-art deep learning-based multi-object detection algorithms was carried out utilizing the designated GPU-based embedded computing modules to obtain detailed metric data about frame rates, as well as the computation power. We also introduce an effective target tracking approach for moving objects. The algorithm for tracking moving objects is based on the extension of simple online and real-time tracking. It was developed by integrating a deep learning-based association metric approach with simple online and real-time tracking (Deep SORT), which uses a hypothesis tracking methodology with Kalman filtering and a deep learning-based association metric. In addition, a guidance system that tracks the target position using a GPU-based algorithm is introduced. Finally, we demonstrate the effectiveness of the proposed algorithms by real-time experiments with a small multi-rotor drone.
A cobalt silylene (Co=Si) linkage enables a distinct metal/ligand cooperative activation of an organic azide, where nitrene transfer occurs to and from the Co⋅⋅⋅Si linkage without ligand dissociation ...from the 18‐electron cobalt center. This process utilizes the orthogonal binding affinities of the silicon and cobalt sites to avoid CO poisoning that would otherwise inhibit reactivity, leading to significantly improved catalytic isocyanate generation compared with related systems. The dual‐site approach demonstrates the potential of metal/main‐group bonds to access new and efficient catalytic pathways.
A powerful approach to cooperative group‐transfer catalysis is demonstrated using the Co=Si bond of a cobalt silylene to provide two distinct sites for substrate activation. The orthogonal selectivity of the Co and Si centers enables efficient nitrene‐group transfer to carbon monoxide by avoiding poisoning that would result from substrates competing for a single reactive site.
Recent advances in the power conversion efficiency (PCE) of organic solar cells (OSCs) have greatly enhanced their commercial viability. Considering the technical standards (e.g., mechanical ...robustness) required for wearable electronics, which are promising application platforms for OSCs, the development of fully stretchable OSCs (f‐SOSCs) should be accelerated. Here, a comprehensive overview of f‐SOSCs, which are aimed to reliably operate under various forms of mechanical stress, including bending and multidirectional stretching, is provided. First, the mechanical requirements of f‐SOSCs, in terms of tensile and cohesion/adhesion properties, are summarized along with the experimental methods to evaluate those properties. Second, essential studies to make each layer of f‐SOSCs stretchable and efficient are discussed, emphasizing strategies to simultaneously enhance the photovoltaic and mechanical properties of the active layer, ranging from material design to fabrication control. Key improvements to the other components/layers (i.e., substrate, electrodes, and interlayers) are also covered. Lastly, considering that f‐SOSC research is in its infancy, the current challenges and future prospects are explored.
A comprehensive overview of fully stretchable organic solar cells (f‐SOSCs), including essential studies to make each layer of an f‐SOSC stretchable and efficient is provided. Various strategies to simultaneously enhance the photovoltaic and mechanical properties of the active layer, ranging from material design to fabrication control, are emphasized.
ABSTRACT
Indole and its derivatives are widespread across different life forms, functioning as signalling molecules in prokaryotes and with more diverse roles in eukaryotes. A majority of indoles ...found in the environment are attributed to bacterial enzymes converting tryptophan into indole and its derivatives. The involvement of indoles among lower organisms as an interspecies and intraspecies signal is well known, with many reports showing that inter‐kingdom interactions involving microbial indole compounds are equally important as they influence defence systems and even the behaviour of higher organisms. This review summarizes recent advances in our understanding of the functional properties of indole and indole derivatives in diverse eukaryotes. Furthermore, we discuss current perspectives on the role of microbial indoles in human diseases such as diabetes, obesity, atherosclerosis, and cancers. Deciphering the function of indoles as biomarkers of metabolic state will facilitate the formulation of diet‐based treatments and open unique therapeutic opportunities.
Chemical bonding dictates not only the optoelectronic properties of materials, but also the intrinsic and extrinsic stability of materials. Here, the causes of intrinsic and extrinsic instability of ...perovskite materials are reviewed considering their correlation with the unique chemical‐bonding nature of perovskite materials. There are a number of key standardized stability tests established by the International Electrotechnical Commission for commercialized photovoltaic modules. Based on these procedures, the possible causes and related mechanisms of the material degradation that can arise during the test procedures are identified, which are discussed in terms of their chemical bonds. Based on the understanding of the critical causes, promising strategies for mitigating the causes to enhance the stability of perovskite solar cells are summarized. The stability of the state‐of‐the‐art perovskite solar cells implies a need for the development of improved stability‐testing protocols to move onto the next stage toward commercialization.
Causes of intrinsic and extrinsic instability of perovskite materials and related mechanisms are discussed in terms of their chemical‐bonding nature. Understanding the critical mechanisms rationalizes the chemical approaches to mitigate the degradation in perovskite solar cells.
Perovskite solar cells with power conversion efficiencies exceeding 16% at AM 1.5G one sun illumination are developed using the black polymorph of formamidnium lead iodide, HC(NH2)2PbI3. Compared ...with CH3NH3PbI3, HC(NH2)2PbI3 extends its absoprtion to 840 nm and shows no phase transition between 296 and 423 K. Moreover, a solar cell based on HC(NH2)2PbI3 exhibits photostability and little I–V hysteresis.
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