The effective application of graphene and other 2D materials is strongly dependent on the industrial-scale manufacturing of films and powders of appropriate morphology and quality. Here, we discuss ...three state-of-the-art mass production techniques, their limitations, and opportunities for future improvement.The industrial application of two-dimensional (2D) materials strongly depends on the large-scale manufacturing of high-quality 2D films and powders. Here, the authors analyze three state-of-the art mass production techniques, discussing the recent progress and remaining challenges for future improvements.
Oxidative modification of low-density lipoprotein (LDL) turns it into an endogenous ligand recognized by pattern-recognition receptors. We have demonstrated that minimally oxidized LDL (mmLDL) binds ...to CD14 and mediates TLR4/MD-2-dependent responses in macrophages, many of which are MyD88-independent. We have also demonstrated that the mmLDL activation leads to recruitment of spleen tyrosine kinase (Syk) to TLR4 and TLR4 and Syk phosphorylation. In this study, we produced a macrophage-specific Syk knockout mouse and used primary Syk(-/-) macrophages in our studies. We demonstrated that Syk mediated phosphorylation of ERK1/2 and JNK, which in turn phosphorylated c-Fos and c-Jun, respectively, as assessed by an in vitro kinase assay. c-Jun phosphorylation was also mediated by IKKε. c-Jun and c-Fos bound to consensus DNA sites and thereby completed an AP-1 transcriptional complex and induced expression of CXCL2 and IL-6. These results suggest that Syk plays a key role in TLR4-mediated macrophage responses to host-generated ligands, like mmLDL, with subsequent activation of an AP-1 transcription program.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Although polycrystalline hexagonal boron nitride (PC-hBN) has been realized, defects and grain boundaries still cause charge scatterings and trap sites, impeding high-performance electronics. Here, ...we report a method of synthesizing wafer-scale single-crystalline hBN (SC-hBN) monolayer films by chemical vapor deposition. The limited solubility of boron (B) and nitrogen (N) atoms in liquid gold promotes high diffusion of adatoms on the surface of liquid at high temperature to provoke the circular hBN grains. These further evolve into closely packed unimodal grains by means of self-collimation of B and N edges inherited by electrostatic interaction between grains, eventually forming an SC-hBN film on a wafer scale. This SC-hBN film also allows for the synthesis of wafer-scale graphene/hBN heterostructure and single-crystalline tungsten disulfide.
A highly stretchable, low-cost strain sensor was successfully prepared using an extremely cost-effective ionic liquid of ethylene glycol/sodium chloride. The hysteresis performance of the ...ionic-liquid-based sensor was able to be improved by introducing a wavy-shaped fluidic channel diminishing the hysteresis by the viscoelastic relaxation of elastomers. From the simulations on visco-hyperelastic behavior of the elastomeric channel, we demonstrated that the wavy structure can offer lower energy dissipation compared to a flat structure under a given deformation. The resistance response of the ionic-liquid-based wavy (ILBW) sensor was fairly deterministic with no hysteresis, and it was well-matched to the theoretically estimated curves. The ILBW sensors exhibited a low degree of hysteresis (0.15% at 250%), low overshoot (1.7% at 150% strain), and outstanding durability (3000 cycles at 300% strain). The ILBW sensor has excellent potential for use in precise and quantitative strain detections in various areas, such as human motion monitoring, healthcare, virtual reality, and smart clothes.
Spleen tyrosine kinase (SYK) is the best known for its involvement in immune receptor signalling, mediated by binding of SYK tandem Src‐homology 2 domains to tandem phosphotyrosine in immunoreceptor ...tyrosine‐based activation motifs (ITAMs). ITAM adaptors or ITAM‐containing receptor tails mediate signalling from B‐ and T‐cell receptors, Fc receptors and many C‐type lectins, including dectin‐1. Recent data point to constitutive binding of SYK to the cytoplasmic domain of toll‐like receptor‐4 (TLR4). This SYK‐TLR4 binding increases upon TLR4 dimerization and phosphorylation, and SYK plays a prominent role in TLR4 signalling in response to LPS in neutrophils and monocytes. SYK also plays an important role in TLR4‐mediated macrophage responses to minimally oxidized low‐density lipoprotein (mmLDL), which is a form of oxidized LDL relevant to development of human atherosclerosis. Interestingly, mmLDL‐induced effects in macrophages, which occur via TLR4, are predominantly MyD88 independent. This unmasks the role of the SYK branch of TLR4 signalling, which mediates modest cytokine release via activation of AP‐1 transcription and robust reactive oxygen species generation and cytoskeletal rearrangements. The latter results in extensive membrane ruffling and macropinocytosis, leading to lipoprotein uptake and foam cell formation, a hallmark of atherosclerotic lesions. Because inhibitors of SYK activity, such as fostamatinib, are in advanced clinical trials for rheumatoid arthritis and other autoimmune diseases, understanding the role of SYK in signalling via TLR4 is of immediate importance. This signalling pathway seems to be particularly important in TLR4 activation by host‐derived, damage‐associated molecular pattern ligands, such as mmLDL, relevant to development of atherosclerosis and other chronic inflammatory diseases.
High‐quality and large‐area molybdenum disulfide (MoS2) thin film is highly desirable for applications in large‐area electronics. However, there remains a challenge in attaining MoS2 film of ...reasonable crystallinity due to the absence of appropriate choice and control of precursors, as well as choice of suitable growth substrates. Herein, a novel and facile route is reported for synthesizing few‐layered MoS2 film with new precursors via chemical vapor deposition. Prior to growth, an aqueous solution of sodium molybdate as the molybdenum precursor is spun onto the growth substrate and dimethyl disulfide as the liquid sulfur precursor is supplied with a bubbling system during growth. To supplement the limiting effect of Mo (sodium molybdate), a supplementary Mo is supplied by dissolving molybdenum hexacarbonyl (Mo(CO)6) in the liquid sulfur precursor delivered by the bubbler. By precisely controlling the amounts of precursors and hydrogen flow, full coverage of MoS2 film is readily achievable in 20 min. Large‐area MoS2 field effect transistors (FETs) fabricated with a conventional photolithography have a carrier mobility as high as 18.9 cm2 V−1 s−1, which is the highest reported for bottom‐gated MoS2‐FETs fabricated via photolithography with an on/off ratio of ≈105 at room temperature.
To synthesize large‐area MoS2 film, a growth substrate is coated with an aqueous solution of Na2MoO4 prior to synthesis. Growth begins with the supply of a liquid sulfur precursor via a bubbling system in an inert atmosphere. With adequate control of the concentration of Na2MoO4 and hydrogen flow, MoS2 film with controlled thickness is grown in 20 min.
Two-dimensional (2D) transition metal dichalcogenides (TMDs) and their heterostructures have attracted significant interest in both academia and industry because of their unusual physical and ...chemical properties. They offer numerous applications, such as electronic, optoelectronic, and spintronic devices, in addition to energy storage and conversion. Atomic and structural modifications of van der Waals layered materials are required to achieve unique and versatile properties for advanced applications. This review presents a discussion on the atomic-scale and structural modifications of 2D TMDs and their heterostructures
via
post-treatment. Atomic-scale modifications such as vacancy generation, substitutional doping, functionalization and repair of 2D TMDs and structural modifications including phase transitions and construction of heterostructures are discussed. Such modifications on the physical and chemical properties of 2D TMDs enable the development of various advanced applications including electronic and optoelectronic devices, sensing, catalysis, nanogenerators, and memory and neuromorphic devices. Finally, the challenges and prospects of various post-treatment techniques and related future advanced applications are addressed.
Atomic and structural modification is an effective method for fine tuning the physical and chemical properties of 2D TMDs and their heterostructures, which enables various advanced applications.
Oxidized cholesteryl esters and inflammation Choi, Soo-Ho; Sviridov, Dmitri; Miller, Yury I.
Biochimica and biophysica acta. Molecular and cell biology of lipids,
04/2017, Letnik:
1862, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The oxidation hypothesis of atherosclerosis proposes that oxidized LDL is a major causative factor in the development of atherosclerosis. Although this hypothesis has received strong mechanistic ...support and many animal studies demonstrated profound atheroprotective effects of antioxidants, which reduce LDL oxidation, the results of human clinical trials with antioxidants were mainly negative, except in selected groups of patients with clearly increased systemic oxidative stress. We propose that even if reducing lipoprotein oxidation in humans might be difficult to achieve, deeper understanding of mechanisms by which oxidized LDL promotes atherosclerosis and targeting these specific mechanisms will offer novel approaches to treatment of cardiovascular disease. In this review article, we focus on oxidized cholesteryl esters (OxCE), which are a major component of minimally and extensively oxidized LDL and of human atherosclerotic lesions. OxCE and OxCE-protein covalent adducts induce profound biological effects. Among these effects, OxCE activate macrophages via toll-like receptor-4 (TLR4) and spleen tyrosine kinase and induce macropinocytosis resulting in lipid accumulation, generation of reactive oxygen species and secretion of inflammatory cytokines. Specific inhibition of OxCE-induced TLR4 activation, as well as blocking other inflammatory effects of OxCE, may offer novel treatments of atherosclerosis and cardiovascular disease. This article is part of a Special Issue entitled: Lipid modification and lipid peroxidation products in innate immunity and inflammation edited by Christoph J. Binder.
•Oxidized cholesteryl esters (OxCE) are a major component of atherosclerotic lesions.•OxCE and OxCE-protein adducts induce profound biological effects.•OxCE induce atherogenic, TLR4- and SYK-dependent macrophages responses.•Blocking inflammatory effects of OxCE may suggest novel atherosclerosis therapy.
Glaucoma is a leading cause of irreversible blindness worldwide and is characterized by a slow, progressive, and multifactorial degeneration of retinal ganglion cells (RGCs) and their axons, ...resulting in vision loss. Despite its high prevalence in individuals 60 years of age and older, the causing factors contributing to glaucoma progression are currently not well characterized. Intraocular pressure (IOP) is the only proven treatable risk factor. However, lowering IOP is insufficient for preventing disease progression. One of the significant interests in glaucoma pathogenesis is understanding the structural and functional impairment of mitochondria in RGCs and their axons and synapses. Glaucomatous risk factors such as IOP elevation, aging, genetic variation, neuroinflammation, neurotrophic factor deprivation, and vascular dysregulation, are potential inducers for mitochondrial dysfunction in glaucoma. Because oxidative phosphorylation stress-mediated mitochondrial dysfunction is associated with structural and functional impairment of mitochondria in glaucomatous RGCs, understanding the underlying mechanisms and relationship between structural and functional alterations in mitochondria would be beneficial to developing mitochondria-related neuroprotection in RGCs and their axons and synapses against glaucomatous neurodegeneration. Here, we review the current studies focusing on mitochondrial dynamics-based structural and functional alterations in the mitochondria of glaucomatous RGCs and therapeutic strategies to protect RGCs against glaucomatous neurodegeneration.
Oxidation reactions are vital parts of metabolism and signal transduction. However, they also produce reactive oxygen species, which damage lipids, proteins and DNA, generating “oxidation-specific” ...epitopes. In this review, we discuss the hypothesis that such common oxidation-specific epitopes are a major target of innate immunity, recognized by a variety of “pattern recognition receptors” (PRRs). By analogy with microbial “pathogen-associated molecular patterns” (PAMPs), we postulate that host-derived, oxidation-specific epitopes can be considered to represent “danger (or damage)-associated molecular patterns” (DAMPs). We also argue that oxidation-specific epitopes present on apoptotic cells and their cellular debris provided the primary evolutionary pressure for the selection of such PRRs. Furthermore, because many PAMPs on microbes share molecular identity and/or mimicry with oxidation-specific epitopes, such PAMPs provide a strong secondary selecting pressure for the same set of oxidation-specific PRRs as well. Because lipid peroxidation is ubiquitous and a major component of the inflammatory state associated with atherosclerosis, the understanding that oxidation-specific epitopes are DAMPs, and thus the target of multiple arcs of innate immunity, provides novel insights into the pathogenesis of atherosclerosis. As examples, we show that both cellular and soluble PRRs, such as CD36, toll-like receptor-4, natural antibodies, and C-reactive protein recognize common oxidation-specific DAMPs, such as oxidized phospholipids and oxidized cholesteryl esters, and mediate a variety of immune responses, from expression of proinflammatory genes to excessive intracellular lipoprotein accumulation to atheroprotective humoral immunity. These insights may lead to improved understanding of inflammation and atherogenesis and suggest new approaches to diagnosis and therapy.
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