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981.
982.
Hongliang Li Woo-Bin Lee Changyi Zhou Duk-Yong Choi Sang-Shin Lee 《Advanced Optical Materials》2021,9(21):2100796
Facilitated by the ability to reflect radiation along its incident direction, retroreflectors have been perceived as a pivotal component for establishing reliable free-space optical links. However, conventional retroreflectors suffer from limited integration because of their bulky size, heavy weight, and nonplanar shape. Metasurface-based devices consisting of subwavelength nanostructures combine semiconductor manufacturing methods with nanophotonics, regarded as a new platform that outperforms geometrical optics. In this paper, a free-space optical link exploiting a flat retroreflector (FRR) based on metasurface doublet is proposed and realized at a telecommunications wavelength of 1550 nm. The top- and bottom-layer metasurfaces, comprising hydrogenated amorphous silicon nanopillars based on a meticulously tailored dielectric spacer of silica, achieve the functions of a transmissive Fourier lens and a concave mirror, respectively. The top transmissive metasurface performs a spatial Fourier transform and its inverse, while the bottom reflective metasurface imposes a spatially varying momentum for reflecting beams along their incident direction. As a proof of concept, the designed FRR, precisely created via lithographical nanofabrication, has been readily applied to forge a substantially reliable free-space optical link, featuring an enhanced angular tolerance of ±25°. This work will initiate a positive prospect for the cooperation between metasurface-based devices and wireless optical communications. 相似文献
983.
Seyeon Oh Chang Hu Choi Bae-Jin Lee Joung-Hyun Park Kuk-Hui Son Kyunghee Byun 《Molecules (Basel, Switzerland)》2021,26(23)
It is well known that oxidative stress induces muscle atrophy, which decreases with the activation of Nrf2/HO-1. Fermented oyster extracts (FO), rich in γ-aminobutyric acid (GABA) and lactate, have shown antioxidative effects. We evaluated whether FO decreased oxidative stress by upregulating Nrf2/HO-1 and whether it decreased NF-κB, leading to decreased IL-6 and TNF-α. Decreased oxidative stress led to the downregulation of Cbl-b ubiquitin ligase, which increased IGF-1 and decreased FoxO3, atrogin1, and Murf1, and eventually decreased muscle atrophy in dexamethasone (Dexa)-induced muscle atrophy animal model. For four weeks, mice were orally administered with FO, GABA, lactate, or GABA+Lactate, and then Dexa was subcutaneously injected for ten days. During Dexa injection period, FO, GABA, lactate, or GABA+Lactate were also administered, and grip strength test and muscle harvesting were performed on the day of the last Dexa injection. We compared the attenuation effect of FO with GABA, lactate, and GABA+lactate treatment. Nrf2 and HO-1 expressions were increased by Dexa but decreased by FO; SOD activity and glutathione levels were decreased by Dexa but increased by FO; NADPH oxidase activity was increased by Dexa but decreased by FO; NF-κB, IL-6, and TNF-α activities were increased by Dexa were decreased by FO; Cbl-b expression was increased by Dexa but restored by FO; IGF-1 expression was decreased by Dexa but increased by FO; FoxO3, Atrogin-1, and MuRF1 expressions were increased by Dexa but decreased by FO. The gastrocnemius thickness and weight were decreased by Dexa but increased by FO. The cross-sectional area of muscle fiber and grip strength were decreased by Dexa but increased by FO. In conclusion, FO decreased Dexa-induced oxidative stress through the upregulation of Nrf2/HO-1. Decreased oxidative stress led to decreased Cbl-b, FoxO3, atrogin1, and MuRF1, which attenuated muscle atrophy. 相似文献
984.
Peter Jaein Choi Petr Tomek Moana Tercel Jhannes Reynisson Thomas In Hyeup Park Elizabeth Alexandra Cooper William Alexander Denny Jiney Jose Euphemia Leung 《Molecules (Basel, Switzerland)》2022,27(3)
The CDK4/6 inhibitor palbociclib, combined with endocrine therapy, has been shown to be effective in postmenopausal women with estrogen receptor-positive, HER2-negative advanced or metastatic breast cancer. However, palbociclib is not as effective in the highly aggressive, triple-negative breast cancer that lacks sensitivity to chemotherapy or endocrine therapy. We hypothesized that conjugation of the near-infrared dye MHI-148 with palbociclib can produce a potential theranostic in triple-negative, as well as estrogen receptor-positive, breast cancer cells. In our study, the conjugate was found to have enhanced activity in all mammalian cell lines tested in vitro. However, the conjugate was cytotoxic and did not induce G1 cell cycle arrest in breast cancer cells, suggesting its mechanism of action differs from the parent compound palbociclib. The study highlights the importance of investigating the mechanism of conjugates of near-infrared dyes to therapeutic compounds, as conjugation can potentially result in a change of mechanism or target, with an enhanced cytotoxic effect in this case. 相似文献
985.
Hae-Lim Kim Sung-Kwon Lee Da-Eun Min Bong-Keun Choi Dong-Ryung Lee 《Molecules (Basel, Switzerland)》2022,27(10)
Dyglomera® is an aqueous ethanol extract of the fruit pods of Dichrostachys glomerata, a Cameroonian spice. Several studies have shown its anti-diabetic and anti-obesity effects. However, the underlying mechanisms for such effects remain unclear. Thus, the objective of this study was to investigate the anti-obesity effect of Dyglomera® and its underlying mechanisms in mice with high-fat diet-induced obesity and 3T3-L1 adipocytes. Our results revealed that Dyglomera® inhibited adipogenesis and lipogenesis by regulating AMPK phosphorylation in white adipose tissues (WATs) and 3T3-L1 adipocytes and promoted lipolysis by increasing the expression of lipolysis-related proteins. These results suggest that Dyglomera® can be used as an effective dietary supplement for treating obesity due to its modulating effect on adipogenesis/lipogenesis and lipolysis. 相似文献
986.
利用等离子体激励器发展了新型的环量增升技术,并对二维NACA0012翼型绕流实施控制。由于NACA0012翼型为尖后缘构型,环量增升装置由2个非对称型介质阻挡放电等离子体激励器构成。一个等离子体激励器贴附于翼型吸力面靠近后缘处,其诱导的壁面射流沿来流方向指向下游;另一个等离子体激励器贴附于翼型压力面靠近后缘处,其诱导的壁面射流与来流方向相反指向上游。在风洞中通过时间解析二维PIV系统对翼型绕流流场进行了测量,基于翼型弦长的雷诺数Re=20 000。结果表明在等离子体激励器的控制下,翼型压力面靠近后缘处可以形成一个定常回流区,从而起到虚拟气动外形的作用,因此翼型吸力面的流场得到加速,压力面的流场得到减速,使得翼型压力面的吸力以及压力面的压力都得到增加,进而增加了翼型的环量。风洞天平测力实验进一步验证了该环量增升技术的有效性。在整个攻角范围内,施加控制的翼型的升力系数相比没有控制的工况有明显的提高。 相似文献
987.
Young J. Hong Junsup Lim Jin S. Choi Klaus D. Weltmann Eun H. Choi 《Plasma Processes and Polymers》2021,18(1)
Nonthermal atmospheric pressure plasmas are widely used in biomedicine and agriculture. Currently, radical density is used as an important parameter for the development of plasma biomedicine and agriculture. Especially, nitrogen dioxide (NO2) and nitric oxide (NO) radicals are significant species in these applications. These could be measured by using the cavity‐enhanced absorption spectroscopy (CEAS) technique. For the NO2 and NO radical density measurement, we used a visible LED (light‐emitting diode) of 660 nm and a mid‐infrared LD (laser diode) of 5238.6 nm, respectively. Radical densities can be calculated with the transmission ratio using Beer–Lambert law, which is obtained by the absorbed amount of laser intensity passed through the gas from the plasma jet in an optical cavity of CEAS. 相似文献
988.
Dr. Anupriya K. Haridas Dr. Milan K. Sadan Dr. Huihun Kim Jungwon Heo Sun Sik Kim Prof. Chang-Ho Choi Prof. Hyun Young Jung Prof. Hyo-Jun Ahn Prof. Jou-Hyeon Ahn 《ChemSusChem》2021,14(8):1936-1947
Iron sulfide (FeS) anodes are plagued by severe irreversibility and volume changes that limit cycle performances. Here, a synergistically coupled hybrid composite, nanoengineered iron sulfide/S-doped graphene aerogel, was developed as high-capacity anode material for Li/Na-ion half/full batteries. The rational coupling of in situ generated FeS nanocrystals and the S-doped rGO aerogel matrix boosted the electronic conductivity, Li+/Na+ diffusion kinetics, and accommodated the volume changes in FeS. This anode system exhibited excellent long-term cyclability retaining high reversible capacities of 422 (1100 cycles) and 382 mAh g−1 (1600 cycles), respectively, for Li+ and Na+ storage at 5 A g−1. Full batteries designed with this anode system exhibited 435 (FeS/srGOA||LiCoO2) and 455 mAh g−1 (FeS/srGOA||Na0.64Co0.1Mn0.9O2). The proposed low-cost anode system is competent with the current Li-ion battery technology and extends its utility for Na+ storage. 相似文献
989.
We investigate the problem of planar conductivity inclusion with imperfect interface conditions. We assume that the inclusion is simply connected. The presence of the inclusion causes a perturbation in the incident background field. This perturbation admits a multipole expansion of which coefficients we call as the generalized polarization tensors (GPTs), extending the previous terminology for inclusions with perfect interfaces. We derive explicit matrix expressions for the GPTs in terms of the incident field, material parameters, and geometry of the inclusion. As an application, we construct GPT-vanishing structures of general shape that result in negligible perturbations for all uniform incident fields. The structure consists of a simply connected core with an imperfect interface. We provide numerical examples of GPT-vanishing structures obtained by our proposed scheme. 相似文献
990.
Bram G. Soliman;Alessia Longoni;Gretel S. Major;Gabriella C. J. Lindberg;Yu Suk Choi;Yu Shrike Zhang;Tim B.F. Woodfield;Khoon S. Lim; 《Macromolecular bioscience》2024,24(5):2300457
Cell encapsulation within three-dimensional hydrogels is a promising approach to mimic tissues. However, true biomimicry of the intricate microenvironment, biophysical and biochemical gradients, and the macroscale hierarchical spatial organizations of native tissues is an unmet challenge within tissue engineering. This review provides an overview of the macromolecular chemistries that have been applied toward the design of cell-friendly hydrogels, as well as their application toward controlling biophysical and biochemical bulk and gradient properties of the microenvironment. Furthermore, biofabrication technologies provide the opportunity to simultaneously replicate macroscale features of native tissues. Biofabrication strategies are reviewed in detail with a particular focus on the compatibility of these strategies with the current macromolecular toolkit described for hydrogel design and the challenges associated with their clinical translation. This review identifies that the convergence of the ever-expanding macromolecular toolkit and technological advancements within the field of biofabrication, along with an improved biological understanding, represents a promising strategy toward the successful tissue regeneration. 相似文献