Photochemical and Patternable Synthesis of 2D Covalent Organic Framework Thin Film Using Dynamic Liquid/Solid Interface.

2D covalent organic frameworks (COFs) are highly porous crystalline materials with promising applications in organic electronics. Current methods involve either on-surface synthesis (solid surface) or interfacial synthesis (liquid/liquid, liquid/gas interface) to create thin films for these applications, each with its drawbacks. On-surface synthesis can lead to contamination from COF powder or unreacted chemicals, while interfacial synthesis risks damaging the film during post-transfer processes. These challenges necessitate the development of alternative synthesis methods for high-quality 2D COF films. This study presents a novel approach for synthesizing homogeneous 2D COF thin films by combining photochemistry and a liquid-flowing system. Leveraging previous work on liquid flow systems to prevent contamination during solvothermal synthesis, this approach to the photochemical method, resulting in the synthesis of high-crystalline 2D COF films with tunable thickness is adopted. The photochemical approach offers spatially controllable energy sources, enabling patternable COF synthesis. Notably, it is successfully fabricated ultrasmooth patterned 2D COF films on hexagonal boron nitride, offering a streamlined process for optoelectronic device fabrication without additional pre, post-processing steps.

Critical Role of Surface Termination of Sapphire Substrates in Crystallographic Epitaxial Growth of MoS2 Using Inorganic Molecular Precursors.

A highly reproducible route for the epitaxial growth of single-crystalline monolayer MoS2 on a C-plane sapphire substrate was developed using vapor-pressure-controllable inorganic molecular precursors MoOCl4 and H2S. Microscopic, crystallographic, and spectroscopic analyses indicated that the epitaxial MoS2 film possessed outstanding electrical and optical properties, excellent homogeneity, and orientation selectivity. The systematic investigation of the effect of growth temperature on the crystallographic orientations of MoS2 revealed that the surface termination of the sapphire substrate with respect to the growth temperature determines the crystallographic orientation selectivity of MoS2. Our results suggest that controlling the surface to form a half-Al-terminated surface is a prerequisite for the epitaxial growth of MoS2 on a C-plane sapphire substrate. The insights on the growth mechanism, especially the significance of substrate surface termination, obtained through this study will aid in designing efficient epitaxial growth routes for developing single-crystalline monolayer transition metal dichalcogenides.

Coaxial scanning holography.

Optical scanning holography requires interference optics, which separates a laser beam into two paths and recombines the two path beams after being modulated spatially and temporarily. This requires high accuracy and stability of the apparatus with a highly coherent light source. In this Letter, we propose a coaxial scanning holography (CSH) capable of realizing scanning holography with high stability and low complexity by forming a scanning beam in a single optical path using a geometrical phase shift. An experimental verification of the CSH by optical acquisition and subsequent reconstruction of the hologram is reported.

Brush-paintable and highly stretchable Ag nanowire and PEDOT:PSS hybrid electrodes.

Highly transparent and stretchable Ag nanowire (NW)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hybrid electrodes were prepared on stretchable polyurethane substrates by using simple and cost-effective brush painting technique. The optimized Ag NW/PEDOT:PSS hybrid electrode showed a sheet resistance of 19.7 Ohm/square and a high optical transmittance of 88.64% comparable to conventional ITO electrode. It was found that shear stress of the paintbrush led to an effective lateral alignment of the Ag NWs into the PEDOT:PSS matrix during brush painting process. In addition, we investigated mechanical properties of the brush painted Ag NW/PEDOT:PSS hybrid electrode using inner/outer bending test, stretching tests, twisting test and rolling test in detail. The optimized brush painted Ag NW/PEDOT:PSS electrode showed a higher strain (~30%) than brush painted Ag NW or sputtered ITO electrode. Furthermore, we demonstrated the outstanding stretchability of brush painted Ag NW/PEDOT:PSS hybrid electrode in two applications: stretchable interconnectors and stretchable electrodes for stretchable and wearable thin film heaters. These results provide clear evidence for its potential and widespread applications in next-generation, stretchable displays, solar cells, and electronic devices.

Stretchable Ag electrodes with mechanically tunable optical transmittance on wavy-patterned PDMS substrates.

We report on semi-transparent stretchable Ag films coated on a wavy-patterned polydimethylsiloxane (PDMS) substrate for use as stretchable electrodes for stretchable and transparent electronics. To improve the mechanical stretchability of the Ag films, we optimized the wavy-pattern of the PDMS substrate as a function of UV-ozone treatment time and pre-strain of the PDMS substrate. In addition, we investigated the effect of the Ag thickness on the mechanical stretchability of the Ag electrode formed on the wavy-patterned PDMS substrate. The semi-transparent Ag films formed on the wavy-patterned PDMS substrate showed better stretchability (strain 20%) than the Ag films formed on a flat PDMS substrate because the wavy pattern effectively relieved strain. In addition, the optical transmittance of the Ag electrode on the wavy-patterned PDMS substrate was tunable based on the degree of stretching for the PDMS substrate. In particular, it was found that the wavy-patterned PDMS with a smooth buckling was beneficial for a precise patterning of Ag interconnectors. Furthermore, we demonstrated the feasibility of semi-transparent Ag films on wavy-patterned PDMS as stretchable electrodes for the stretchable electronics based on bending tests, hysteresis tests, and dynamic fatigue tests.

Synthesis of reduced graphene oxide/thorn-like titanium dioxide nanofiber aerogels with enhanced electrochemical performance for supercapacitor.

Reduced graphene oxide (rGO)/thorn-like TiO2 nanofiber (TTF) aerogels, or GTTF aerogels, with different TTF weight ratios were successfully prepared by electrospinning, silica etching and hydrothermal combination method. During the hydrothermal reaction, the rGO nanosheets and TTF self-assembled into three-dimensional (3D) interconnected networks, in which the TTF is loaded onto the rGO nanosheets. The electrochemical performance of the GTTF aerogels was assessed using cyclic voltammetry and galvanostatic charge-discharge measurements in a 1M aqueous Na2SO4 electrolyte. The TTF-to-rGO ratio of the aerogel material significantly affected the electrochemical performance of the aerogel electrodes, and the GTTF aerogels prepared with 20wt% TTF (denoted GTTF-20) exhibited excellent electrochemical performance. The maximum specific capacitance of this aerogel electrode was 178F/g at a current density of 1A/g. The GTTF-20 aerogel also exhibited good electrochemical stability with a capacitance degradation of less than 10% after 3000cycles. We can deduce that the electrochemical performance of the as-prepared aerogels may be enhanced by increasing the chemical interactions between rGO and TiO2. The results indicate that the GTTF aerogels show enormous potential for application in energy storage devices.

Roll-to-roll slot-die coating of 400 mm wide, flexible, transparent Ag nanowire films for flexible touch screen panels.

We report fabrication of large area Ag nanowire (NW) film coated using a continuous roll-to-roll (RTR) slot die coater as a viable alternative to conventional ITO electrodes for cost-effective and large-area flexible touch screen panels (TSPs). By controlling the flow rate of shear-thinning Ag NW ink in the slot die, we fabricated Ag NW percolating network films with different sheet resistances (30-70 Ohm/square), optical transmittance values (89-90%), and haze (0.5-1%) percentages. Outer/inner bending, twisting, and rolling tests as well as dynamic fatigue tests demonstrated that the mechanical flexibility of the slot-die coated Ag NW films was superior to that of conventional ITO films. Using diamond-shape patterned Ag NW layer electrodes (50 Ohm/square, 90% optical transmittance), we fabricated 12-inch flexible film-film type and rigid glass-film-film type TSPs. Successful operation of flexible TSPs with Ag NW electrodes indicates that slot-die-coated large-area Ag NW films are promising low cost, high performance, and flexible transparent electrodes for cost-effective large-area flexible TSPs and can be substituted for ITO films, which have high sheet resistance and are brittle.

Higher glycated hemoglobin level is associated with increased risk for ischemic stroke in non-diabetic korean male adults.

BACKGROUND: The role of glycated hemoglobin (HbA1c) in the prediction of ischemic stroke in non-diabetic subjects is not clear. We performed a study to analyze the role of HbA1c in the risk prediction of ischemic stroke in non-diabetic Korean males adult. METHODS: A total of 307 non-diabetic male patients with ischemic stroke were enrolled, and 253 age-matched control subjects without a history of diabetes, hypertension, or cardiovascular disease were selected from a Health Check-up database. Anthropometric measurement data, fasting glucose level, lipid profile, and HbA1c level were available for all subjects. Associations of the variables and the presence or absence of ischemic stroke were analyzed. RESULTS: The ischemic stroke patient group had significantly higher HbA1c levels (5.8±0.5% vs. 5.5±0.5%, P<0.01) and mean systolic and diastolic blood pressure compared with the control group. Among the variables, smoking, low high density lipoprotein cholesterol, systolic blood pressure, and HbA1c were the significant determinants for ischemic stroke. The highest quartile of HbA1c showed a 9.6-fold increased odds ratio for ischemic stroke compared with the lowest quartile of HbA1c (odds ratio, 9.596; 95% confidence interval, 3.859 to 23.863, P<0.01). The proportion of ischemic stroke patients showed a significant trend for increment as the deciles of HbA1c increased (P for trend <0.01). CONCLUSION: Higher HbA1c indicated a significantly increased risk for ischemic stroke after adjusting for other confounding variables in non-diabetic Korean adult males. HbA1c might have significance in predicting the risk for ischemic stroke even in the non-diabetic range.

Inhibition of cytokine expression by a butanol extract from Cordyceps bassiana.

Cordyceps species have been known since long as a multi-utility ethnomedicinal herbal in Korea, China and Japan. It has been reported to exhibit a number of properties such as anti-oxidative, anti-cancer, antiinflammatory, anti-diabetic, and anti-obesity effects. In a previously conducted study, we had demonstrated that the ethanol extract of Cordyceps bassiana was able to suppress the production of interleukin (IL)-12 and interferon (IFN)-gamma in macrophages and T lymphocytes. In this study, we were able to further explore the molecular basis of its inhibitory mechanism using a butanol fraction of this herbal (Cb-BF) preparation. Similarly, this fraction also blocked the expression of cytokines such as IL-12 and tumor necrosis factor (TNF)-alpha as well as the proliferation of splenic lymphocytes and their production of IFN-gamma but not IL-4. Cb-BF suppressed the luciferase activities that are mediated by nuclear factor (NF)-kappaB, activator protein (AP)-1, and signal transducers and activators of transcription (STAT)-1. In agreement with this, these fractions diminished the translocation of the transcription factors into the nucleus. The study also demonstrated that the upstream signaling events for the activation of these factors such as spleen tyrosine kinase (Syk), janus kinase (JAK)-2, and extracellular signal-regulated kinase (ERK) were suppressed. Therefore, these results suggest that the butanol extract of Cordyceps bassiana may contain more than one active component capable of inhibiting the inflammatory signaling cascade and this can be considered as a potential candidate for treatment of diseases that require suppression of immune system.

Capsiate, a nonpungent capsaicin-like compound, inhibits angiogenesis and vascular permeability via a direct inhibition of Src kinase activity.

Capsiate, a nonpungent capsaicin analogue, and its dihydroderivative dihydrocapsiate are the major capsaicinoids of the nonpungent red pepper cultivar CH-19 Sweet. In this study, we report the biological actions and underlying molecular mechanisms of capsiate on angiogenesis and vascular permeability. In vitro, capsiate and dihydrocapsiate inhibited vascular endothelial growth factor (VEGF)-induced proliferation, chemotactic motility, and capillary-like tube formation of primary cultured human endothelial cells. They also inhibited sprouting of endothelial cells in the rat aorta and formation of new blood vessels in the mouse Matrigel plug assay in response to VEGF. Moreover, both compounds blocked VEGF-induced endothelial permeability and loss of vascular endothelial (VE)-cadherin-facilitated endothelial cell-cell junctions. Importantly, capsiate suppressed VEGF-induced activation of Src kinase and phosphorylation of its downstream substrates, such as p125(FAK) and VE-cadherin, without affecting autophosphorylation of the VEGF receptor KDR/Flk-1. In vitro kinase assay and molecular modeling studies revealed that capsiate inhibits Src kinase activity via its preferential docking to the ATP-binding site of Src kinase. Taken together, these results suggest that capsiate could be useful for blocking pathologic angiogenesis and vascular permeability caused by VEGF.

Ethanol extract of Inonotus obliquus inhibits lipopolysaccharide-induced inflammation in RAW 264.7 macrophage cells.

Inonotus obliquus (Pers.:Fr.) Pil. is a white rot fungus that belongs to the family Hymenochaetaceae of Basidiomycetes. Extracts and fractions of this fungus have been known to have biological activities, including antimutagenic, anticancer, antioxidative, and immunostimulating effects. Recently, there have been reports that the anti-inflammatory and antinociceptive properties of the methanol extract of I. obliquus may be due to the inhibition of inducible nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2) expression via the down-regulation of nuclear factor kappaB (NF-kappaB) binding activity. However, the effects of I. obliquus on Akt and mitogen-activated protein kinase (MAPK) activation of inflammatory mediator production have not yet been elucidated. In the present study, a 70% ethanol extract of I. obliquus (IOE70) showed antioxidative effects. We also tested the ability of the I. obliquus extract to inhibit the inflammatory cascades in lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells. The NO inhibition of IOE70 was better than that of other ethanol extracts from I. obliquus. To investigate the mechanism by which IOE 70 inhibits NO production and iNOS and COX-2 expression, we examined the activations of IkappaBalpha, Akt, and c-Jun NH(2) -terminal kinase (JNK) in LPS-activated macrophages. IOE70 markedly inhibited the phosphorylation of IkappaBalpha, Akt, and MAPKs in dose-dependent manners in LPS-activated macrophages. Taken together, these experiments demonstrated that IOE70 inhibition of LPS-induced expression of iNOS and COX-2 protein is mediated by Akt and JNK. Based on our findings, the most likely mechanism that can account for this biological effect of IOE70 involves the inhibition of NF-kappaB through the phosphatidylinositol 3-kinase/Akt/IkappaB pathway and the inhibition of JNK activation. Thus, IOE70 might have useful clinical applications in the management of inflammatory diseases and may also be useful as a medicinal food.

Stable Formation of Fruiting Body in Cordyceps bassiana.

In order to breed a Cordyceps bassiana isolate that stably forms fruiting body in artificial cultivation, isolates derived from subculturing and single spores were tested through mating. From C. bassiana EFCC 783, three subcultured isolates EFCC 2830, EFCC 2831 and EFCC 2832 were obtained and fourteen single conidial isolates were obtained from these three subcultured isolates. Two different morphological types were found in the fourteen single conidial isolates. One type was able to form synnemata and another type was not able to form synnemata. Since switch of morphological type was not observed despite their continuous subculturing, cross was performed between the two types and the formation of fruiting body was examined. Ascospores were obtained from a selected fruiting body formed by hybrid of the cross. Self-cross and combinational cross of the ascospore-derived isolates generated hybrids that stably produce high quality fruiting body in artificial media.

Enhanced inhibition of murine tumor and human breast tumor xenografts using targeted delivery of an antibody-endostatin fusion protein.

Endostatin can inhibit angiogenesis and tumor growth in mice. A potential limitation of endostatin as an antitumor agent in humans is the short serum half-life of the protein that may decrease effective concentration at the site of tumor and necessitate frequent dosing. In an effort to improve antitumor activity, endostatin was fused to an antibody specific for the tumor-selective HER2 antigen to create an antibody-endostatin fusion protein (anti-HER2 IgG3-endostatin). Normal endostatin rapidly cleared from serum in mice (T(1/2)(2), = 0.6-3.8 hours), whereas anti-HER2 IgG3-endostatin had a prolonged half-life (90% intact; T(1/2)(2), 40.2-44.0 hours). Antigen-specific targeting of anti-HER2 IgG3-endostatin was evaluated in BALB/c mice implanted with CT26 tumors or CT26 tumors engineered to express the HER2 antigen (CT26-HER2). Radio-iodinated anti-HER2 IgG3-endostatin preferentially localized to CT26-HER2 tumors relative to CT26 tumors. Administration of anti-HER2 IgG3-endostatin to mice showed preferential inhibition of CT26-HER2 tumor growth compared with CT26. Anti-HER2 IgG3-endostatin also markedly inhibited the growth of human breast cancer SK-BR-3 xenografts in severe combined immunodeficient mice. Anti-HER2 IgG3-endostatin inhibited tumor growth significantly more effectively than endostatin, anti-HER2 IgG3 antibody, or the combination of antibody and endostatin. CT26-HER2 tumors treated with the endostatin fusion protein had decreased blood vessel density and branching compared with untreated CT26-HER2 or CT26 treated with the fusion protein. The enhanced effectiveness of anti-HER2 IgG3-endostatin may be due to a longer half-life, improved serum stability, and selective targeting of endostatin to tumors, resulting in decreased angiogenesis. Linking of an antiangiogenic protein, such as endostatin, to a targeting antibody represents a promising and versatile approach to antitumor therapy.

Genetic Analysis of Pigmentation in Cordyceps militaris.

Pigmentation of ascospore-derived isolates from seven different natural specimens of Cordyceps militaris EFCC C-5888, EFCC C-7159, EFCC C-7833, EFCC C-7991, EFCC C-8021, EFCC C-8023 and EFCC C-8179 was observed on the plates of Sabouraud Dextrose agar plus Yeast Extract at 25℃ under continuous illumination (500 lux). Pigmentation of the wild-type isolates of C. militaris was diverse ranging from yellowish white to orange, while white color was believed as a mutant. Inheritance of pigmentation was found to be controlled by both parental isolates when F1 progeny were analyzed. Pigmentation and mating type were shown to be either independent or distantly linked each other due to the high percentage of non-parental phenotypes among F1 progeny. Crosses between white mutant isolates of C. militaris yielded progeny with wild type pigmentations, indicating that the albino mutations in the parents were unlinked to each other.

Methanol extract of Cordyceps pruinosa inhibits in vitro and in vivo inflammatory mediators by suppressing NF-kappaB activation.

Cordyceps pruinosa has been used in traditional folk medicine to treat numerous diseases. The molecular mechanism of C. pruinosa pharmacological and biochemical actions of macrophages in inflammation has not been clearly elucidated. We examined how the methanol extract of C. pruinosa regulates production of IL-1beta, TNF-alpha, nitric oxide (NO), and prostaglandin E(2) (PGE(2)) in vitro and in vivo. The extract inhibits these inflammatory mediators in LPS-stimulated murine macrophage cell line RAW264.7 and primary macrophages, by suppressing gene expression of IL-1beta, TNF-alpha, inducible nitric oxide synthase, and cyclooxygenase-2. Moreover, the extract suppresses the nuclear transcription factor NF-kappaB activation in LPS-stimulated RAW264.7 cells. Administration of the extract significantly decreases the plasma levels of these inflammatory mediators in LPS-injected mice. These results suggest that the C. pruinosa methanol extract suppresses inflammation through suppression of NF-kappaB-dependent inflammatory gene expression, suggesting that the C. pruinosa extract may be beneficial for treatment of endotoxin shock or sepsis.