This paper presents a deep learning method for faster magnetic resonance imaging (MRI) by reducing k-space data with sub-Nyquist sampling strategies and provides a rationale for why the proposed approach works well. Uniform subsampling is used in the time-consuming phase-encoding direction to capture high-resolution image information, while permitting the image-folding problem dictated by the Poisson summation formula. To deal with the localization uncertainty due to image folding, a small number of low-frequency k-space data are added. Training the deep learning net involves input and output images that are pairs of the Fourier transforms of the subsampled and fully sampled k-space data. Our experiments show the remarkable performance of the proposed method; only 29[Formula: see text] of the k-space data can generate images of high quality as effectively as standard MRI reconstruction with the fully sampled data.

Colloidal silver nanoparticles were obtained by chemical reduction of silver nitrate in water with sodium borohydride (NaBH 4 ) in the presence of sodium dodecyl sulfate (SDS) as a stabilizer. The obtained nanoparticles were characterized by their UV-vis absorption spectra and transmission electron micrograph (TEM) images. The UV-vis absorption spectra showed that NaBH 4 served not only as a reducing agent but also as a stabilizer, which protects the aggregation of silver nanoparticles. The TEM images showed that the particles were dispersed better with increasing the NaBH 4 concentration.

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With the great interest in "plasmonics", metallic nano structures have been used for optical applications. The accompanying optical resonance, known as surface plasmon resonance (SPR), has highly motivated researchers because this unique optical phenomenon shows strong interaction with lights within a tiny volume of space. Surface plasmons (SPs) in optically thin metal fi lms contribute to extraordinary optical transmission (EOT) through subwavelength apertures. [ 1 ] Therefore, researchers have suggested plasmonic color fi lters (PCFs) with a selective fi ltering function in subwavelength metallic holes. [2][3][4][5][6] Color fi lters, widely used for the industrial devices such as organic light emitting diodes, liquid crystal displays, and CMOS image sensors, are composed of organic dyes. The fi ltering performance originating from the color sensitivity of the dyes is degraded by heat and ultraviolet radiation due to the low chemical stability of the organic materials. [ 7 ] In addition, the complex structure requires a highly-accurate aligned lithography to spatially separate colors by pixel unit.On the other hand, PCFs have an optically thin metal layer, and their transmittance can be tuned by the geometrical and material conditions: the periodicity, size and shape of holes, the thickness of metal, and the optical constants of the materials. This simple and thin structure is advantageous for assembly into other devices without worry about degradation by heat and light. More recently, PCFs integrated on top of the CMOS image sensor have been reported, [ 6 ] and experimental analysis of spatial cross talk and the effect of defect has been performed in detail. [ 5 ] These results have shown greater possibility for PCFs in industrial applications. However, the fabrication methods used up to now to make plasmonic structures, such as nanoimprinting, [ 8 ] electron beam lithography [2][3][4][5][6] or the focused ion beam method, [ 1,9 ] restrict mass-production of PCFs, leading to problems of low speed, small patterning area, and high cost of equipment.Here we suggest a fabrication fl ow including a laser interference lithography (LIL) step. Contrary to above-mentioned technologies, LIL, with simple maskless equipment, yields perfect ordering patterns, which are, as they must be, spatially coherent over a large area. Although LIL has a limitation in that it can only fabricate simple periodic patterns, it is an attractive additional solution to add to the conventional methods for applications in which periodic patterns are desirable. [ 10 ] In this regard, fabrication of plasmonic color fi lters with LIL enables us to suggest the easiest method to achieve large size PCFs without losing performance aspect. Additionally, a single pixel of the PCFs can be reduced to 1 µm-size; [ 5 ] the interference pattern, with a period of hundreds of nm, is small enough to separate the patterned area into pixel units. Thus, it is possible to effect spatial separation of colors by simple shadow masking and multi exposure. More compli...

In mid/low rectal cancer with clinically metastatic LPNs, the decision to perform LPND should be based on the LPN response to nCRT.