Study on ZrSi2 as a Candidate Material for Extreme Ultraviolet Pellicles.

An extreme ultraviolet (EUV) pellicle is an ultrathin membrane at a stand-off distance from the reticle surface that protects the EUV mask from contamination during the exposure process. EUV pellicles must exhibit high EUV transmittance, low EUV reflectivity, and superior thermomechanical durability that can withstand the gradually increasing EUV source power. This study proposes an optimal range of optical constants to satisfy the EUV pellicle requirements based on the optical simulation results. Based on this, zirconium disilicide (ZrSi2), which is expected to satisfy the optical and thermomechanical requirements, was selected as the EUV pellicle candidate material. An EUV pellicle composite comprising a ZrSi2 thin film deposited via co-sputtering was fabricated, and its thermal, optical, and mechanical properties were evaluated. The emissivity increased with an increase in the thickness of the ZrSi2 thin film. The measured EUV transmittance (92.7%) and reflectivity (0.033%) of the fabricated pellicle satisfied the EUV pellicle requirements. The ultimate tensile strength of the pellicle was 3.5 GPa. Thus, the applicability of the ZrSi2 thin film as an EUV pellicle material was verified.

FPGA Implementation of the Chirp-Scaling Algorithm for Real-Time Synthetic Aperture Radar Imaging.

Synthetic aperture radar (SAR), which can generate images of regions or objects, is an important research area of radar. The chirp scaling algorithm (CSA) is a representative SAR imaging algorithm. The CSA has a simple structure comprising phase compensation and fast Fourier transform (FFT) operations by replacing interpolation for range cell migration correction (RCMC) with phase compensation. However, real-time processing still requires many computations and a long execution time. Therefore, it is necessary to develop a hardware accelerator to improve the speed of algorithm processing. In addition, the demand for a small SAR system that can be mounted on a small aircraft or drone and that satisfies the constraints of area and power consumption is increasing. In this study, we proposed a CSA-based SAR processor that supports FFT and phase compensation operations and presents field-programmable gate array (FPGA)-based implementation results. We also proposed a modified CSA flow that simplifies the traditional CSA flow by changing the order in which the transpose operation occurs. Therefore, the proposed CSA-based SAR processor was designed to be suitable for modified CSA flow. We designed the multiplier for FFT to be shared for phase compensation, thereby achieving area efficiency and simplifying the data flow. The proposed CSA-based SAR processor was implemented on a Xilinx UltraScale+ MPSoC FPGA device and designed using Verilog-HDL. After comparing the execution times of the proposed SAR processor and the ARM cortex-A53 microprocessor, we observed a 136.2-fold increase in speed for the 4096 × 4096-pixel image.

Hypercompact adenine base editors based on transposase B guided by engineered RNA.

Transposon-associated transposase B (TnpB) is deemed an ancestral protein for type V, Cas12 family members, and the closest ancestor to UnCas12f1. Previously, we reported a set of engineered guide RNAs supporting high indel efficiency for Cas12f1 in human cells. Here we suggest a new technology whereby the engineered guide RNAs also manifest high-efficiency programmable endonuclease activity for TnpB. We have termed this technology TaRGET (TnpB-augment RNA-based Genome Editing Technology). Having this feature in mind, we established TnpB-based adenine base editors (ABEs). A Tad-Tad mutant (V106W, D108Q) dimer fused to the C terminus of dTnpB (D354A) showed the highest levels of A-to-G conversion. The limited targetable sites for TaRGET-ABE were expanded with engineered variants of TnpB or optimized deaminases. Delivery of TaRGET-ABE also ensured potent A-to-G conversion rates in mammalian genomes. Collectively, the TaRGET-ABE will contribute to improving precise genome-editing tools that can be delivered by adeno-associated viruses, thereby harnessing the development of clustered regularly interspaced short palindromic repeats (CRISPR)-based gene therapy.

Sequential Bilateral Hip Fractures in Elderly Patients.

PURPOSE: To evaluate the incidence and presentation of osteoporotic sequential bilateral hip fractures (SBHF) in Center for Joint Disease, Chonnam National University Hwasun Hospital as there are limited studies with variable results reported in Korea. MATERIALS AND METHODS: Records of 507 patients aged >60 years old presenting with osteoporotic hip fractures between 2009 and 2015 were retrospectively reviewed to document the occurrence and presentation of sequential hip fractures; mean post-treatment follow-up was 48 months. Additionally, any correlations between sequential fractures and initial fracture and risk factors were assessed. Bone mineral density (BMD) was measured before and after sequential hip fracture for comparison. RESULTS: There were 246 femoral neck (Group A) and 261 intertrochanteric (Group B) fractures. The cumulative incidence of SBHF was 8.2% (42 patients total; 29 in Group A and 13 in Group B). Average interval of SBHF for Group A and Group B were 37.4 months and 29.9 months, respectively. There was significant correlation between the initial fracture type and sequential fractures, particularly the trochanteric and subgroup of those with neck fractures. Hypertension as a co-morbidity and female sex have been identified as risk factors for SBHF. No significant findings were noted regarding BMD and risk factors in both groups. CONCLUSION: The clinical presentations of SBHF noted here concur with other worldwide studies and may guide efforts to develop relevant programs to prevent SBHF.

Maximal strength and endurance scores of the tongue, lip, and cheek in healthy, normal Koreans.

OBJECTIVES: The purpose of this study was to establish normative data for healthy Korean adults by measuring the maximal strength and endurance scores of the tongue, lip, and cheek, and to examine correlations between these measurements. MATERIALS AND METHODS: This study included 120 subjects that were divided into three groups according to age: young (20-39 years), middle-aged (40-59 years), and older (over 60 years); and by gender. Measurements were taken using the Iowa Oral Performance Instrument (IOPI). RESULTS: The mean maximal tongue strengths were as follows: young men (46.7±10.2 kPa) and women (32.1±7.9 kPa), middle-aged men (40.9±9.3 kPa) and women (36.9±8.6 kPa), and older men (35.2±9.0 kPa) and women (34.5±6.9 kPa). The mean tongue endurance scores were: young men (28.8±12.6 seconds) and women (20.8±13.5 seconds), middle-aged men (17.0±8.5 seconds) and women (15.3±5.2 seconds), and older men (15.8±6.7 seconds) and women (17.9±8.1 seconds). The mean maximal lip strengths were: young men (11.6±3.0 kPa) and women (11.4±3.8 kPa), middle-aged men (11.4±4.2 kPa) and women (11.1±5.1 kPa), and older men (14.5±3.9 kPa) and women (11.7±2.6 kPa). The mean lip endurance scores were: young men (41.1±23.9 seconds) and women (22.4±21.7 seconds), middle-aged men (24.3±10.3 seconds) and women (30.5±13.4 seconds), and older men (24.9±11.0 seconds) and women (12.8±7.6 seconds). The mean maximal cheek strengths were: young men (24.5±4.6 kPa) and women (20.5±4.3 kPa), middle-aged men (25.2±6.4 kPa) and women (21.2±5.5 kPa), and older men (22.4±5.3 kPa) and women (18.0±4.8 kPa). The mean cheek endurance scores were: young men (47.8±24.4 seconds) and women (43.9±25.0 seconds), middle-aged men (27.3±11.3 seconds) and women (20.0±14.6 seconds), and older men (21.7±14.5 seconds) and women (17.2±11.4 seconds). CONCLUSION: The data collected in this study will provide an important database of standardized measurements for maximal strength and endurance scores of the tongue, lip and cheek in healthy, normal Koreans.