다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Metamaterials, or engineered materials with rationally designed, subwavelength-scale building blocks, allow us to control the behavior of physical fields in optical, microwave, radio, acoustic, heat transfer, and other applications with flexibility and performance that are unattainable with naturally available materials. In turn, metasurfaces-planar, ultrathin metamaterials-extend these capabilities even further. Optical metasurfaces offer the fascinating possibility of controlling light with surface-confined, flat components. In the planar photonics concept, it is the reduced dimensionality of the optical metasurfaces that enables new physics and, therefore, leads to functionalities and applications that are distinctly different from those achievable with bulk, multilayer metamaterials. Here, we review the progress in developing optical metasurfaces that has occurred over the past few years with an eye toward the promising future directions in the field.

/pdf/planar-photonics-with-metasurfaces-1sfd62lis7.pdf

Planar Photonics with Metasurfaces

Subwavelength resolution imaging requires high numerical aperture (NA) lenses, which are bulky and expensive. Metasurfaces allow the miniaturization of conventional refractive optics into planar structures. We show that high-aspect-ratio titanium dioxide metasurfaces can be fabricated and designed as metalenses with NA = 0.8. Diffraction-limited focusing is demonstrated at wavelengths of 405, 532, and 660 nm with corresponding efficiencies of 86, 73, and 66%. The metalenses can resolve nanoscale features separated by subwavelength distances and provide magnification as high as 170×, with image qualities comparable to a state-of-the-art commercial objective. Our results firmly establish that metalenses can have widespread applications in laser-based microscopy, imaging, and spectroscopy.

Metalenses at visible wavelengths: Diffraction-limited focusing and subwavelength resolution imaging.

Carbon nanotubes (CNTs) have been considered a prominent nano-channel in cell membranes because of their prominent ion-conductance and ion-selectivity, offering agents for a biomimetic channel platform. Using a coarse-grained molecular dynamics simulation, we clarify a construction mechanism of vertical CNT nano-channels in a lipid membrane for a long period, which has been difficult to observe in previous CNT-lipid interaction simulations. The result shows that both the lipid coating density and length of CNT affect the suitable fabrication condition for a vertical and stable CNT channel. Also, simulation elucidated that a lipid coating on the surface of the CNT prevents the CNT from burrowing into the lipid membrane and the vertical channel is stabilized by the repulsion force between the lipids in the coating and membrane. Our study provides an essential understanding of how CNTs can form stable and vertical channels in the membrane, which is important for designing new types of artificial channels as biosensors for bio-fluidic studies.

https://iopscience.iop.org/article/10.1088/1361-6528/aaa77b/pdf

Understanding carbon nanotube channel formation in the lipid membrane

Powder injection molding (PIM) is an advanced manufacturing technology with advantages including shape complexity, high production rate, and high physical/mechanical properties. However, because PIM has many sub-steps, such as mixing, injection molding, debinding, and sintering, the optimization of each process condition is important to avoid defects including warpage, crack, and blister. In this paper, the warpage, one of the most common defects in PIM, is investigated by using thin square copper structures with lengths of 10 mm and thicknesses of 600 and 190 μm. The warpage of each structure is measured by using a white light interferometric surface profiler. The measured warpage of the structure fabricated by the standard process is 3.771 μm. When the solvent debinding step is absent, the warpage becomes 8.052 μm. Additionally, sensitivity analysis determines that the effect of the thermal debinding step’s heating rate is dominant to warp the structure. Normalized sensitivities of the debinding heating rates are 0.58 for the structure with a thickness of 600 μm and 0.63 for the other structure. Finally, how to optimize the processing condition is outlined.

Warpage of Powder Injection Molded Copper Structure

Miniaturized devices with multiple functionalities are exceedingly required in integrated optical systems. Flat nanostructures, named metasurfaces, provide fascinating boulevard for complex structuring and manipulation of light such as optical vortex generation, lensing, imaging, harmonic generation etc. at micron scale. Since, the performance of metal-based plasmonic metasurfaces is significantly limited by their optical absorption and losses, lossless dielectric materials (in the operational spectrum) provide decent alternative to attain higher efficiency. Here, a novel, polarization insensitive and highly efficient method for light structuring is demonstrated based on amorphous silicon (with subwavelength thickness of 400 nm) at an operational wavelength of 633 nm. The proposed phase gradient metasurface is based on circular cylindrical nanopillars of amorphous silicon exhibits two optical properties, the lensing and orbital angular momentum generation. The cylindrical nature of the pillar plays a pivotal role to make the overall structure as polarization insensitive. The proposed innovative methodology will provide an interesting road towards the development and realization of multi-functional ultrathin nanodevices which will find numerous applications in integrated photonics.

Micron-scale light structuring via flat nanodevices

Spectral beam combining technique is a simple and straightforward method to obtain high power laser beam. The beam combining system typically consists of three parts, fiber laser array, transform optical system and diffraction grating. Performance of the system (diffraction efficiency and laser induced damage threshold) is mainly determined by the diffraction grating. This paper describes a multilayer dielectric diffraction gating with high diffraction efficiency and low laser induced damage threshold, which can be potentially used to obtain a high power laser by combing laser beams. The diffraction grating is designed by coupled-wave analysis, and single-beam laser interference lithography is used to fabricate diffraction gratings. To verify the optical and thermal characteristics of the beam, we measure diffraction efficiency and the threshold for laser-induced damage. FEM simulation accurately represented temperature distribution in the grating during laser irradiation. This work provides integrated methods that include design of multilayer dielectric gratings, thermal analysis and device characterization using high power laser.

Junsuk Rho

Papers

Understanding carbon nanotube channel formation in the lipid membrane

Warpage of Powder Injection Molded Copper Structure

Micron-scale light structuring via flat nanodevices

Optical characterizations and thermal analyses of HfO2/SiO2 multilayered diffraction gratings for high-power continuous wave laser

The role of current loop in harmonic generation from magnetic metamaterials in two polarizations