Search

Stabilization annealing (SA) treatment is often performed on precipitation-hardened IN706 (Ni-37.7Fe-15.6Cr–3Nb-1.7Ti-0.23Al) before aging to improve the resistance to creep, while sacrificing the tensile properties. In this study, the effect of SA treatment on fatigue crack propagation (FCP) behavior of IN706 at 25 and 650 °C was examined based on detailed fractographic and micrographic analyses. IN706 specimen with SA treatment at 845 °C for 3 h showed a considerable amount of η precipitates, that were located along grain boundaries and within grains. It was found that η precipitates, particularly those linearly aligned within grains, provided easy crack path, reducing the resistance to FCP of IN706 at both 25 and 650 °C.

This article presents a capacitance readout (CR) IC for both 2-D touch and 3-D proximity sensing. By employing hysteresis loop (HL) filtering and an external noise-monitoring schemes, the proposed CR IC solves reduced sensitivity in mutual-capacitance proximity sensing. Based on this HL filtering, irregular movements of a proximity object between 5-mm and 20-mm hover heights are identified. Moreover, using in-phase signals on multiple Tx electrodes simplifies the 3-D proximity data post-processing. This allows the 2-D touch sensing analog-front-end (AFE) to be reused for 3-D proximity without extra circuitry, leading to a cost-effective AFE architecture appropriate for mass production. The proposed CR IC was fabricated via a 350 nm CMOS process. The proposed AFE achieves 26 dB 3-D proximity signal-to-noise ratio (SNR) with 416 Hz scan rate. The active area of the reconfigurable AFE is 6.24 mm2 while the full-chip including AFE, MCU, digital logic, and memory occupies 15.02 mm2. The power consumption with in-phase driving of 6 Tx electrodes and sensing with 4 Rx electrodes for proximity sensing is 6.7 mW.

Real-time Monte Carlo denoising aims to denoise a 1spp-rendered image with a limited time budget. Many latest techniques for real-time Monte Carlo denoising utilize temporal accumulation (TA) as a pre-processing to improve the temporal stability of successive frames and increase the effective spp. However, existing techniques using TA used to suffer from significant performance degradation when TA does not work well. In addition, they have the disadvantage of deteriorating performance in dynamic scenes because pixel information of the current frame cannot be sufficiently utilized due to the pixel averaging effect between temporally adjacent frames. To solve this problem, this paper proposes a framework that utilizes both 1spp images and temporally accumulated 1spp (TA-1spp) images. First, the multi-scale kernel prediction module estimates kernel maps for filtering 1spp images and TA-1spp images, respectively. Then, the filtered images are properly fused so that the two advantages of 1spp and TA-1spp images can create synergy. Also, the remaining noise is removed through the refinement module and fine details are reconstructed to improve the model flexibility, beyond using only the kernel prediction module. As a result, we achieve better quantitative and qualitative performance at 39% faster than state-of-the-art (SOTA) real-time Monte Carlo denoisers.

Abstract Messenger RNA (mRNA) therapy is the intracellular delivery of mRNA to produce desired therapeutic proteins. Developing strategies for local mRNA delivery is still required where direct intra‐articular injections are inappropriate for targeting a specific tissue. The mRNA delivery efficiency depends on protecting nucleic acids against nuclease‐mediated degradation and safe site‐specific intracellular delivery. Herein, novel mRNA‐releasing matrices based on RGD‐moiety‐rich gelatin methacryloyl (GelMA) microporous annealed particle (MAP) scaffolds are reported. GelMA concentration in aerogel‐based microgels (µgels) produced through a microfluidic process, MAP stiffnesses, and microporosity are crucial parameters for cell adhesion, spreading, and proliferation. After being loaded with mRNA complexes, MAP scaffolds composed of 10% GelMA µgels display excellent cell viability with increasing cell infiltration, adhesion, proliferation, and gene transfer. The intracellular delivery is achieved by the sustained release of mRNA complexes from MAP scaffolds and cell adhesion on mRNA‐releasing scaffolds. These findings highlight that hybrid systems can achieve efficient protein expression by delivering mRNA complexes, making them promising mRNA‐releasing biomaterials for tissue engineering.

The tumor microenvironment consists of diverse, complex etiological factors. The matrix component of pancreatic ductal adenocarcinoma (PDAC) plays an important role not only in physical properties such as tissue rigidity but also in cancer progression and therapeutic responsiveness. Although significant efforts have been made to model desmoplastic PDAC, existing models could not fully recapitulate the etiology to mimic and understand the progression of PDAC. Here, two major components in desmoplastic pancreatic matrices, hyaluronic acid- and gelatin-based hydrogels, are engineered to provide matrices for tumor spheroids composed of PDAC and cancer-associated fibroblasts (CAF). Shape analysis profiles reveals that incorporating CAF contributes to a more compact tissue formation. Higher expression levels of markers associated with proliferation, epithelial to mesenchymal transition, mechanotransduction, and progression are observed for cancer-CAF spheroids cultured in hyper desmoplastic matrix-mimicking hydrogels, while the trend can be observed when those are cultured in desmoplastic matrix-mimicking hydrogels with the presence of transforming growth factor-β1 (TGF-β1). The proposed multicellular pancreatic tumor model, in combination with proper mechanical properties and TGF-β1 supplement, makes strides in developing advanced pancreatic models for resembling and monitoring the progression of pancreatic tumors, which could be potentially applicable for realizing personalized medicine and drug testing applications.

The fatigue crack propagation (FCP) behavior of L-PBF (laser-powder bed fusion) and DED (direct energy deposition) Ti–6Al–4V (Ti64) specimens with different crack directions (CDs) were studied in air and 3.5% NaCl solution under controlled potential, and the results were compared to that of CM (conventional manufacturing) Ti64 specimen. Among the specimens tested, L-PBF Ti64 specimen showed the lowest resistance to FCP, followed by DED and CM Ti64 specimens. The effect of CD with respect to building direction (BD) was negligible on the FCP behavior of L-PBF and DED Ti64 specimens. The micrographic and fractographic analyses suggested that refined microstructure was responsible for the FCP behavior of L-PBF and DED Ti64 specimens. L-PBF and DED Ti64 specimens were susceptible to EAFCP (environment-assisted FCP) in 3.5% NaCl solution, while the sensitivity was not as significant as that of CM counterpart. The sensitivity to EAFCP of L-PBF and DED Ti64 specimens was related to crack bifurcation, rather than intrinsic environmental degradation in Cl− bearing environment.

An image in a display device under strong illuminance can be perceived as darker than the original due to the nature of the human visual system (HVS). In order to alleviate this degradation in terms of software, existing schemes employ global luminance compensation or tone mapping. However, since such approaches focus on restoring luminance only, it has a fundamental drawback that chrominance cannot be sufficiently restored. Also, the previous approaches seldom provide acceptable visibility because it does not consider the content of an input image. Furthermore, because they focus mainly on global image quality, they may show unsatisfactory image quality for certain local areas. This paper introduces VisibilityNet, a neural network model designed to restore both chrominance and luminance. By leveraging VisibilityNet, we generate an optimally enhanced dataset tailored to the ambient light conditions. Furthermore, employing the generated dataset and a convolutional neural network (CNN), we estimate weighted piece-wise linear enhancement curves (WPLECs) that take into account both ambient light and image content. These WPLECs effectively enhance global contrast by addressing both luminance and chrominance aspects. Ultimately, through the utilization of a salient object detection algorithm that emulates the HVS, visibility enhancement is achieved not only for the overall region but also for visually salient areas. We verified the performance of the proposed method by comparing it with five existing approaches in terms of two quantitative metrics for a dataset we built ourselves. Experimental findings substantiate that the proposed method surpasses alternative approaches by significantly improving visibility.

Abstract Indocyanine green (ICG), glucose oxidase (GOx), and copper(II) sulfate (Cu)‐installed hybrid gel based on organic nanorod (cellulose nanocrystal [CNC]) and inorganic nanodisk (Laponite [LAP]) was developed to perform a combination of starvation therapy (ST), chemodynamic therapy (CDT), and photothermal therapy (PTT) for localized cancers. A hybrid CNC/LAP network with a nematic phase was designed to enable instant gelation, controlled viscoelasticity, syringe injectability, and longer in vivo retention. Moreover, ICG was introduced into the CNC/LAP gel system to induce hyperthermia of tumor tissue, amplifying the CDT effect; GOx was used for glucose deprivation (related to the Warburg effect); and Cu was introduced for hydroxyl radical generation (based on Fenton‐like chemistry) and cellular glutathione (GSH) degradation in cancer cells. The ICG/GOx/Cu‐installed CNC/LAP gel in combination with near‐infrared (NIR) laser realized improved antiproliferation, cellular reactive oxygen species (ROS) generation, cellular GSH degradation, and apoptosis induction in colorectal cancer (CT‐26) cells. In addition, local injection of the CNC/ICG/GOx/Cu/LAP gel into the implanted CT‐26 tumor while irradiating it with NIR laser provided strong tumor growth suppression effects. In conclusion, the designed hybrid nanorod/nanodisk gel network can be efficiently applied to the local PTT/ST/CDT of cancer cells.

Abstract Aerogel‐based biomaterials are increasingly being considered for biomedical applications due to their unique properties such as high porosity, hierarchical porous network, and large specific pore surface area. Depending on the pore size of the aerogel, biological effects such as cell adhesion, fluid absorption, oxygen permeability, and metabolite exchange can be altered. Based on the diverse potential of aerogels in biomedical applications, this paper provides a comprehensive review of fabrication processes including sol‐gel, aging, drying, and self‐assembly along with the materials that can be used to form aerogels. In addition to the technology utilizing aerogel itself, it also provides insight into the applicability of aerogel based on additive manufacturing technology. To this end, how microfluidic‐based technologies and 3D printing can be combined with aerogel‐based materials for biomedical applications is discussed. Furthermore, previously reported examples of aerogels for regenerative medicine and biomedical applications are thoroughly reviewed. A wide range of applications with aerogels including wound healing, drug delivery, tissue engineering, and diagnostics are demonstrated. Finally, the prospects for aerogel‐based biomedical applications are presented. The understanding of the fabrication, modification, and applicability of aerogels through this study is expected to shed light on the biomedical utilization of aerogels.

Environment-assisted fracture (EAF) behavior of direct energy deposition (DED) Ti–6Al–4V (Ti64) specimen was investigated using a slow strain rate test (SSRT) method in air and 3.5% NaCl solution under controlled potentials, where the susceptibility to EAF was described by the reduction in tensile elongation (RTE) with exposure to aggressive environment. It was found that RTE value of DED Ti64 specimen was approximately 4 times greater than that of conventional manufacturing (CM) counterpart. The fractographic analysis on DED Ti64 specimen tested in 3.5% NaCl solution suggested that crack-like discontinuity was instantly formed from corrosion damages by merging into band-like lack of fusion (LOF) near the surface. Since LOFs were developed perpendicular to build direction (BD), the RTE value of DED Ti64 specimen with tensile direction (TD) perpendicular to BD was approximately 4 times lower than those with TD parallel to BD. Excellent correlation between the area fraction of LOF and the RTE was observed, indicating that LOFs were responsible for high susceptibility to EAF of DED Ti64 specimen in Cl− bearing environment.

Counting CD4+ T lymphocytes using flow cytometry is a standard method for monitoring patients with HIV infections. Simpler and cheaper alternatives to flow cytometry are in high demand because getting access to flow cytometers is difficult or impossible in resource-limited settings. We evaluated the performance of the Microscanner Plus, a simple and automated image-based cell counter, in determining CD4 counts against a flow cytometer. CD4 count results of the Microscanner Plus and flow cytometer were compared using samples from 47 HIV-infected patients and 87 healthy individuals. All CV% for precision and reproducibility tests were less than 10%. The Microscanner Plus’s lowest detectable CD4 count was determined to be 15.27 cells/µL of whole blood samples. The correlation coefficient (R) between Microscanner Plus and flow cytometry for CD4 counting in 134 clinical samples was very high, at 0.9906 (p < 0.0001). The automated Microscanner Plus showed acceptable analytical performance for counting CD4+ T lymphocytes and may be particularly useful for monitoring HIV patients in resource-limited settings.

After three years of the SARS-CoV-2 pandemic, the demand for developing field-deployable point-of-care (PoC) molecular diagnostic tests has increased. Although RT-qPCR is the molecular diagnostic gold standard and is accurate, it is not readily applied to point-of-care testing (POCT). Meanwhile, rapid diagnostic kits have the disadvantage of low sensitivity. Recently, rapid isothermal nucleic acid amplification technology has emerged as an alternative for rapid diagnosis. Here, we developed a rapid SARS-CoV-2 reverse transcription loop-mediated isothermal amplification (RT-LAMP)-lateral flow assay (LFA) kit. This kit includes a Chelex-100/boiling nucleic acid extraction device and a one-step amplification detection apparatus capable of performing the entire process, from RNA extraction to detection, and diagnosing SARS-CoV-2 infection within 40 min without contamination. The detection limits of the rapid SARS-CoV-2 RT-LAMP-LFA kit were 100 plaque-forming units (PFUs) mL−1 and 10−1 PFU mL−1 for RNA samples extracted using the Chelex-100/boiling nucleic acid extraction device and commercial AdvansureTM E3 system, respectively. The sensitivity and specificity of the rapid SARS-CoV-2 RT-LAMP-LFA kit were 97.8% and 100%, respectively. Our SARS-CoV-2 RT-LAMP-LFA kit exhibited high sensitivity and specificity within 40 min without requiring laboratory instruments, suggesting that the kit could be used as a rapid POC molecular diagnostic test for SARS-CoV-2.

Influenza and coronaviruses cause highly contagious respiratory diseases that cause millions of deaths worldwide. Public health measures implemented during the current coronavirus disease (COVID-19) pandemic have gradually reduced influenza circulation worldwide. As COVID-19 measures have relaxed, it is necessary to monitor and control seasonal influenza during this COVID-19 pandemic. In particular, the development of rapid and accurate diagnostic methods for influenza and COVID-19 is of paramount importance because both diseases have significant public health and economic impacts. To address this, we developed a multi-loop-mediated isothermal amplification (LAMP) kit capable of simultaneously detecting influenza A/B and SARS-CoV-2. The kit was optimized by testing various ratios of primer sets for influenza A/B (FluA/FluB) and SARS-CoV-2 and internal control (IC). The FluA/FluB/SARS-CoV-2 multiplex LAMP assay showed 100% specificity for uninfected clinical samples and sensitivities of 90.6%, 86.89%, and 98.96% for LAMP kits against influenza A, influenza B, and SARS-CoV-2 clinical samples, respectively. Finally, the attribute agreement analysis for clinical tests indicated substantial agreement between the multiplex FluA/FluB/SARS-CoV-2/IC LAMP and commercial AllplexTM SARS-CoV-2/FluA/FluB/RSV assays.

Tuberculosis (TB) is one of the leading causes of infectious mortality from a single infectious agent, Mycobacterium tuberculosis (MTB). This study evaluated the performance of the newly developed BZ TB/NTM NALF assay, which integrated loop-mediated isothermal amplification and lateral flow immunochromatographic assay technologies, for the detection of MTB. A total of 80 MTB-positive samples and 115 MTB-negative samples were collected, all of which were confirmed by TB real-time PCR (RT-PCR) using either AdvanSureTM TB/NTM RT-PCR Kit or Xpert® MTB/RIF Assay. The performance of the BZ TB/NTM NALF assay was evaluated by calculating its sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in comparison to those of the RT-PCR methods. Compared to the RT-PCR, the sensitivity, specificity, PPV, and NPV of BZ TB/NTM NALF assay were 98.7%, 99.1%, 98.7%, and 99.1%, respectively. The concordance rate between BZ TB/NTM NALF and RT-PCR was 99.0%. Rapid and simple detection of MTB is essential for global case detection and further elimination of TB. The performance of the BZ TB/NTM NALF Assay is acceptable with a high concordance with RT-PCR, indicating that it is reliable for use in a low-resource environment.

This paper proposes a novel method that uses stator current signals to detect motor faults under operational speed and load torque conditions. Previous studies on motor current signature analysis (MCSA) have been devoted to developing methods to detect faults in non-stationary conditions; however, they have limitations. Conventional methods require much domain knowledge or parameter selection for signal decomposition, and are applicable under limited variable conditions. Thus, this paper proposes a new feature, drive-tolerant current residual variance (DTCRV), for fault detection. This new approach requires no domain knowledge and is applicable under varying speed and load torque conditions. In the proposed method, first, the envelope of the current signal is calculated to extract its modulation. Second, the drive-related signal, which greatly varies based on speed and load torque conditions, is extracted from the enveloped current signal. Third, the drive-tolerant current residual (DTCR) is calculated; the DTCR is defined as the subtraction of the drive-related signal from the enveloped current signal. Finally, the new health feature is calculated as the variance of the DTCR. To demonstrate the proposed method, experimental studies were conducted under several operating conditions (i.e., different speed profiles and load torque levels) with two fault modes: 1) a stator inter-turn short and 2) misalignment. Results confirm the ability of DTCRV to promptly and accurately detect faults in a variety of conditions; in contrast, conventional methods are greatly affected by the operating conditions.

This paper presents a front-end architecture for touch screen panel (TSP) readout in a TSP-integrated, ultrathin flexible display to mitigate severe display noise interference, which is an uncommon mode caused by the large panel load of the TSP in the flexible display. The differential sensing method with multireference TSP channels minimized an imbalance of the phase and amplitude of the coupled-display noise interference. In addition, cascaded time-discrete bandpass sampling was employed to enhance the touch sensitivity in the sensing block. Moreover, a rated front-end block could be reconfigured to a differential or single-ended sensing structure, which reused the prefilter capacitors in the differential sensing for offset cancellation in reference capacitance sensing. To further improve the sensitivity, programmable postfiltering was employed on the reference TSP channels. Subsequently, the proposed front-end was implemented in a 350 nm process, wherein it achieved a SNR of 50.5 dB with a scan rate of 200 Hz and attenuated aggravated display noise interference by more than 6.84 dB as compared to the conventional differential sensing method. The designed chip occupied an area of 4.8 mm2 and consumed 17.6 mW from a 3 V supply.

Leaks in water distribution systems should be detected to avoid economic, environmental, and social problems. Existing Bayesian Inference based time-domainreflectometry (TDR) methods for leak detection have a limitation for real applications due to the lengthy time in building sample data. As the pipeline distance becomes longer and multiple leaks must be considered in long distance pipelines, the computational time for building training data gets larger. This paper proposes a scattering-parameter-based forward model to relieve computational burden of the existing TDR methods. It was shown that the proposed model outperformed the existing RLGC-based forward model in terms of computational time. The proposed model that is combined with Bayesian inference and TDR signal modeling is validated with an experimental pipeline, leak detectors, transmission line, and TDR instrument for leak detection. In summary, the proposed method is promising for leak detection in long pipelines as well as multiple leaks.