In the railway sector, rolling stock and infrastructure must be maintained in perfect condition to ensure reliable and safe operation for passengers. Climate change is affecting the urban and regional infrastructure through sea level rise, water accumulations, river flooding, and other increased-frequency extreme natural situations (heavy rains or snows) which pose a challenge to maintenance. In this paper, the use of artificial intelligence based on predictive maintenance implementation is proposed for the early detection of degraded conditions of a bridge due to extreme climatic conditions.
View Article and Find Full Text PDFRadiation tolerance is determined as the ability of crystalline materials to withstand the accumulation of the radiation induced disorder. Nevertheless, for sufficiently high fluences, in all by far known semiconductors it ends up with either very high disorder levels or amorphization. Here we show that gamma/beta (γ/β) double polymorph GaO structures exhibit remarkably high radiation tolerance.
View Article and Find Full Text PDFThe extracellular matrix (ECM) is pivotal in modulating tumor progression. Besides chemically stimulating tumor cells, it also offers physical support that orchestrates the sequence of events in the metastatic cascade upon dynamically modulating cell mechanosensation. Understanding this translation between matrix biophysical cues and intracellular signaling has led to rapid growth in the interdisciplinary field of cancer mechanobiology in the last decade.
View Article and Find Full Text PDFAtomic layer deposition (ALD) is a vapor-phase technique that consists of the alternation of separated self-limiting surface reactions, which enable film thickness to be accurately controlled at the angstrom level, based on the former atomic layer epitaxy method [...
View Article and Find Full Text PDFThe cell nucleus is a dynamic structure that changes locales during cellular processes such as proliferation, differentiation, or migration, and its mispositioning is a hallmark of several disorders. As with most mechanobiological activities of adherent cells, the repositioning and anchoring of the nucleus are presumed to be associated with the organization of the cytoskeleton, the network of protein filaments providing structural integrity to the cells. However, demonstrating this correlation between cytoskeleton organization and nuclear position requires the parameterization of the extraordinarily intricate cytoskeletal fiber arrangements.
View Article and Find Full Text PDFDespite recent advances in biofabrication, recapitulating complex architectures of cell-laden vascular constructs remains challenging. To date, biofabricated vascular models have not yet realized four fundamental attributes of native vasculatures simultaneously: freestanding, branching, multilayered, and perfusable. In this work, a microfluidics-enabled molding technique combined with coaxial bioprinting to fabricate anatomically relevant, cell-laden vascular models consisting of hydrogels is developed.
View Article and Find Full Text PDFThis chapter summarizes the current biomaterials and associated technologies used to mimic and characterize the tumor microenvironment (TME) for developing preclinical therapeutics. Research in conventional 2D cancer models systematically fails to provide physiological significance due to their discrepancy with diseased tissue's native complexity and dynamic nature. The recent developments in biomaterials and microfabrication have enabled the popularization of 3D models, displacing the traditional use of Petri dishes and microscope slides to bioprinters or microfluidic devices.
View Article and Find Full Text PDFStructural coloration is a recurring solution in biological systems to control visible light. In nature, basic structural coloration results from light interacting with a repetitive nanopattern, but more complex interactions and striking results are achieved by organisms incorporating additional hierarchical structures. Artificial reproduction of single-level structural color has been achieved using repetitive nanostructures, with flat sheets of inverse opals being very popular because of their simple and reliable fabrication process.
View Article and Find Full Text PDFHypertrophic cardiomyopathy (HOCM) is the most common genetic heart disorder and the most common cause of sudden cardiac death among young population and a major cause of disability for patients of any age. An extended transaortic septal myectomy is the definitive treatment. It is very important to have a good knowledge of the characteristic pathophysiology of the disease in order to optimize intraoperative treatment of these patients.
View Article and Find Full Text PDFSelf-propelled microscopic organisms are ubiquitous in water. Such organisms' motility depends on hydrodynamic and physical factors related to the rheology of the surrounding media and biological factors depending on the organisms' state and well-being. Here we demonstrate that the swimming speed of Paramecium aurelia, a unicellular protozoan, globally found in fresh, brackish, and salt waters, can be used as a measurable frugal indicator of the presence of pollutants in water.
View Article and Find Full Text PDFObjectives: Prolonged surgical retraction may cause atelectasis. We aimed to recruit collapsed alveoli, stepwise, monitored by lung dynamic compliance and observe effects on arterial oxygenation and systemic and graft hemodynamics. Secondarily, we observed alveolar recruitment effects on postoperative mechanical ventilation, international normalized ratio, and pulmonary complications.
View Article and Find Full Text PDFGiven plans to revisit the lunar surface by the late 2020s and to take a crewed mission to Mars by the late 2030s, critical technologies must mature. In missions of extended duration, in situ resource utilization is necessary to both maximize scientific returns and minimize costs. While this present a significantly more complex challenge in the resource-starved environment of Mars, it is similar to the increasing need to develop resource-efficient and zero-waste ecosystems on Earth.
View Article and Find Full Text PDFMaterials for three-dimensional cultures aim to reproduce the function of the extracellular matrix, enabling cell adhesion and growth by remodeling the environment. However, embryonic stem cells (ESCs) must develop in environments that prevent adhesion and preserve their pluripotency. In this study, we used cellulose nanofiber hydrogels to mimic the developing conditions required for ESCs.
View Article and Find Full Text PDFThe creation of structural composites with combined strength, toughness, low density, and biocompatibility remains a long-standing challenge. On the other hand, bivalve marine shells--exhibit strength, stiffness, and toughness that surpass even that of the nacre that is the most widely mimicked model for structural composites. The superior mechanical properties of shells originate from their cross-lamella design, comprising CaCO mineral platelets arranged in an "interlocked" herringbone fashion.
View Article and Find Full Text PDFBioinspired manufacturing, in the sense of replicating the way nature fabricates, may hold great potential for supporting a socioeconomic transformation towards a sustainable society. Use of unmodified ubiquitous biological components suggests for a fundamentally sustainable manufacturing paradigm where materials are produced, transformed into products and degraded in closed regional systems with limited requirements for transport. However, adoption is currently limited by the fact that despite their ubiquitous nature, these biopolymers are predominantly harvested as industrial and agricultural products.
View Article and Find Full Text PDFHerein, we present the synthesis of surface-oxidized cellulose nanofiber (CNF) hydrogel and characterization with various physicochemical analyses and spectroscopic tools as well as its suitability for cellular encapsulation and delivery. The structure-property relationship as shear thinning, thixotropy, creep-recovery and stimuli responsiveness are explored. The CNF hydrogel is capable to inject possessing shear thinning behavior at shear rate (~10 s) range in the normal injecting process.
View Article and Find Full Text PDFCellulose is the most abundant and broadly distributed organic compound and industrial by-product on Earth. However, despite decades of extensive research, the bottom-up use of cellulose to fabricate 3D objects is still plagued with problems that restrict its practical applications: derivatives with vast polluting effects, use in combination with plastics, lack of scalability and high production cost. Here we demonstrate the general use of cellulose to manufacture large 3D objects.
View Article and Find Full Text PDFNatural biomaterials, such as chitosan and collagen, are useful for biomedical applications because they are biocompatible, mechanically robust, and biodegradable, but it is difficult to rapidly and tightly bond them to living tissues. In this study, we demonstrate that the microbial transglutaminase (mTG), can be used to rapidly (<5 min) bond chitosan and collagen biomaterials to the surfaces of hepatic, cardiac, and dermal tissues, as well as to functionalized polydimethylsiloxane (PDMS) materials that are used in medical products. The mTG-bonded chitosan patches effectively sealed intestinal perforations, and a newly developed two-component mTG-bonded chitosan spray effectively repaired ruptures in a breathing lung when tested ex vivo.
View Article and Find Full Text PDFConstitutively active splice variants of androgen receptor (AR-Vs) lacking ligand-binding domain (LBD) are a mechanism of resistance to androgen receptor LBD-targeted (AR LBD-targeted) therapies for metastatic castration-resistant prostate cancer (CRPC). There is a strong unmet clinical need to identify prostate cancer patients with AR-V-positive lesions to determine whether they will benefit from further AR LBD-targeting therapies or should receive taxanes or investigational drugs like EPI-506 or galeterone. Both EPI-506 (NCT02606123) and galeterone (NCT02438007) are in clinical trials and are proposed to have efficacy against lesions that are positive for AR-Vs.
View Article and Find Full Text PDFHormone therapies for advanced prostate cancer target the androgen receptor (AR) ligand-binding domain (LBD), but these ultimately fail and the disease progresses to lethal castration-resistant prostate cancer (CRPC). The mechanisms that drive CRPC are incompletely understood, but may involve constitutively active AR splice variants that lack the LBD. The AR N-terminal domain (NTD) is essential for AR activity, but targeting this domain with small-molecule inhibitors is complicated by its intrinsic disorder.
View Article and Find Full Text PDFA material inspired by natural insect cuticle and composed of chitosan and fibroin is created. The material exhibits the strength of an aluminum alloy at half its weight, while being clear, biocompatible, biodegradable, and micromoldable. The bioinspired laminate exhibits strength and toughness that are ten times greater than the unstructured component blend and twice that of its strongest constituent.
View Article and Find Full Text PDFJ Med Chem
January 2012
Extracts of the marine sponge Niphates digitalis collected in Dominica showed strong activity in a cell-based assay designed to detect antagonists of the androgen receptor (AR) that could act as lead compounds for the development of a new class of drugs to treat castration recurrent prostate cancer (CRPC). Assay-guided fractionation showed that niphatenones A (3) and B (4), two new glycerol ether lipids, were the active components of the extracts. The structures of 3 and 4 were elucidated by analysis of NMR and MS data and confimed via total synthesis.
View Article and Find Full Text PDFA method for the simultaneous (bio)chemical and topographical patterning of enclosed structures in poly(dimethyl siloxane) (PDMS) is presented. The simultaneous chemical and topography transference uses a water-soluble chitosan sacrificial mold to impart a predefined pattern with micrometric accuracy to a PDMS replica. The method is compared to conventional soft-lithography techniques on planar surfaces.
View Article and Find Full Text PDFA general method for construction of three dimensional structures by directed assembly of microscale polymeric sub-units is presented. Shape-controlled microgels are directed to assemble into different shapes by limiting their movement onto a molded substrate. The capillary forces, resulting from the presence of a liquid polymer, assemble the microgels in close contact with the rest of the units and with the free surface, the latter imposing the final geometry of the resulting construct.
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