Amplified fluorogenic immunoassay for early diagnosis and monitoring of Alzheimer's disease from tear fluid.

Accurate diagnosis of Alzheimer's disease (AD) in its earliest stage can prevent the disease and delay the symptoms. Therefore, more sensitive, non-invasive, and simple screening tools are required for the early diagnosis and monitoring of AD. Here, we design a self-assembled nanoparticle-mediated amplified fluorogenic immunoassay (SNAFIA) consisting of magnetic and fluorophore-loaded polymeric nanoparticles. Using a discovery cohort of 21 subjects, proteomic analysis identifies adenylyl cyclase-associated protein 1 (CAP1) as a potential tear biomarker. The SNAFIA demonstrates a low detection limit (236 aM), good reliability (R2 = 0.991), and a wide analytical range (0.320-1000 fM) for CAP1 in tear fluid. Crucially, in the verification phase with 39 subjects, SNAFIA discriminates AD patients from healthy controls with 90% sensitivity and 100% specificity in under an hour. Utilizing tear fluid as a liquid biopsy, SNAFIA could potentially aid in long-term care planning, improve clinical trial efficiency, and accelerate therapeutic development for AD.

A 37-40 GHz 6-Bits Switched-Filter Phase Shifter Using 150 nm GaN HEMT.

In this paper, we present a 6-bit phase shifter designed and fabricated using the 150 nm GaN HEMT process. The designed phase shifter operates within the n260 (37~40 GHz) band, as specified in the 5G NR standard, and employs the structure of a switched-filter phase shifter. By serially connecting six single-bit phase shifters, ranging from 180° to 5.625°, the designed phase shifter achieves a phase range of 360°. The fabricated phase shifter exhibits a minimum insertion loss of 5 dB and an RMS phase error of less than 5.36° within the 37 to 40 GHz. This phase shifter is intended for seamless integration with high-power RF circuits.

Aptamer-linked in vitro expression assay for ultrasensitive detection of biomarkers.

Signal amplification is a key step that determines the sensitivity of molecular assays. Although studies on aptamers have mostly focused on their target-binding ability, taking advantage of the gene-coding function of nucleic acids, we demonstrate here that aptamers can be engineered into diagnostic reagents that can both recognize a target and generate highly amplified detection signals. We developed a strategy that employs a 'readable' aptamer that consists of a single-stranded aptamer and a double-stranded reporter gene. After binding to its target via the aptamer region, the reporter gene of the readable aptamer produces amplified number of signal-generating enzymes through a subsequent in vitro expression reaction. In contrast to conventional enzyme-conjugation methods, this method allows the generation of far more amplified detection signals, thereby markedly increasing the sensitivity of detection enough to analyze a target present in aM concentrations.

A highly sensitive and versatile transcription immunoassay using a DNA-encoding tandem repetitive light-up aptamer.

Highly sensitive and accurate measurements of protein biomarkers are crucial for early diagnosis and disease monitoring. Here we report a versatile detection platform for sensitive detection of a protein biomarker using a tandem repeat Spinach aptamer DNA-based transcription immunoassay, which is a immunoassay combined with transcription-assisted Spinach RNA aptamer generation. We designed a DNA template encoding spa tandem repetitive Spinach sequence for enhanced generation of an RNA aptamer. The tandem repeated Spinach DNA template is consist of multiple monomeric units which is composed of T7 promoter, Spinach-2 and terminator. After in vitro transcription, the fluorescence signal from the 16R (nR, n = number of repeats) DNA template was enhanced up to ~ 15-fold compared to a single form (1R) DNA template. Using tandem repeat DNA, the proposed transcription immunoassay showed a limit of detection (LOD) of 37 aM, which is 103-fold lower than that of the conventional enzyme-linked immunosorbent assay (ELISA). The results demonstrate substantial promise for the ultrasensitive detection of various biological analytes using simple ELISA techniques. The high sensitivity and reliability of the proposed transcription immunoassay offer great promise for clinical assays.

Hot-Rolling and a Subsequent Direct-Quenching Process Enable Superior High-Cycle Fatigue Resistance in Ultra-High Strength Low Alloy Steels.

The current study investigated the effect of hot rolling reduction rate of ultra-high strength low alloy steel manufactured via the direct quenching process on microstructure, tensile and high-cycle fatigue properties of the alloy. In order to control the reduction rate of ultra-high strength steels (UHSSs) differently, the steels were produced with two different thicknesses, 6 mm (46.2%-reduction rate, A) and 15 mm (11.5%-reduction rate, B). Then, the two alloys were directly quenched under the same conditions. Both the UHSSs showed martensite in the near surface region and auto-tempered martensite and bainite in the center region. Tensile results showed that alloy A with higher fraction of finer martensite had higher yield strength by about 180 MPa (1523 MPa) than alloy B. The alloy A was also found to possess a higher tensile strength (~2.1 GPa) than alloy B. In addition, alloy A had higher strength than B, and the elongation of A was about 4% higher than that of alloy B. High-cycle fatigue results showed that the fatigue limits of alloys A and B were 1125 MPa and 1025 MPa, respectively. This means that alloy A is excellent not only in strength but also high-cycle fatigue resistance. Based on the above results, the correlation between the microstructure and deformation behaviors were also discussed.

Anisotropy of Compressive Deformation Behavior in Cold Sprayed Cu Bulk Material.

This study is related to cold spray 3D printing (kinetic metallization) capable of manufacturing near-net shape material. Anisotropy on the compressive deformation behavior of pure copper materials manufactured using cold spray process was investigated. In addition, the deformed microstructures that change according to strain were analyzed with different direction (spraying direction, perpendicular direction). Cu bulk material manufactured through cold spray processes showed distinctive structures wherein high-density dislocations had been accumulated because individual powder particles collided at high speed. After compression with different direction, spraying direction showed 330 MPa yield strength, 437 MPa compressive peak stress and perpendicular direction showed 327 MPa (Y.S.), 422 MPa (C.P.S). In low strain condition, dynamic recovery occurred in internal dislocation structures, thereby showing strain softening phenomena even at room temperature. For a closed examine of anisotropy on the compressive deformation and fracture behavior, we used SEM, FE-SEM, XRD, EBSD and observed microstructure and fractography with different direction.

Estimation of Apple Intake for the Exposure Assessment of Residual Chemicals Using Korea National Health and Nutrition Examination Survey Database.

The aims of this study were to develop strategies and algorithms of calculating food commodity intake suitable for exposure assessment of residual chemicals by using the food intake database of Korea National Health and Nutrition Examination Survey (KNHANES). In this study, apples and their processed food products were chosen as a model food for accurate calculation of food commodity intakes uthrough the recently developed Korea food commodity intake calculation (KFCIC) software. The average daily intakes of total apples in Korea Health Statistics were 29.60 g in 2008, 32.40 g in 2009, 34.30 g in 2010, 28.10 g in 2011, and 24.60 g in 2012. The average daily intakes of apples by KFCIC software was 2.65 g higher than that by Korea Health Statistics. The food intake data in Korea Health Statistics might have less reflected the intake of apples from mixed and processed foods than KFCIC software has. These results can affect outcome of risk assessment for residual chemicals in foods. Therefore, the accurate estimation of the average daily intake of food commodities is very important, and more data for food intakes and recipes have to be applied to improve the quality of data. Nevertheless, this study can contribute to the predictive estimation of exposure to possible residual chemicals and subsequent analysis for their potential risks.