Ferulic acid isolated from
Tetragonia tetragonioides
was tested for its whitening effect on the B16F10 mouse melanoma cell line and its anti-wrinkle activity on the CCD-986sk human dermal fibroblast ...cell line. Ferulic acid, one of the primary phenolic compounds that can be isolated from
T. tetragonioides
, has been reported to show potential as a functional food, for its whitening effect and anti-wrinkle activity. To measure its whitening and anti-wrinkle activities, cells were treated with ferulic acid isolated from
T. tetragonioides
at concentrations between 5 and 20 μM. Ferulic acid showed no cytotoxicity at concentrations up to 20 μM. Ferulic acid inhibited melanin synthesis, tyrosinase expression, and microphthalmia transcription factor expression in B16F10 cells stimulated with α-melanocyte stimulating hormone. Ferulic acid induced procollagen synthesis, hyaluronic acid synthesis, tissue inhibitor of metalloproteinase synthesis, and inhibited matrix metalloproteinase (MMP)-1 and MMP-9 expression in CCD-986sk cells stimulated with UV-B. On the basis of these results, we conclude that ferulic acid isolated from
T. tetragonioides
shows potential for use as a functional food, with whitening and anti-wrinkle activities.
Anion doping is one of the most widely adopted strategies to improve the electrochemical performance of cathode materials for Li-ion batteries. However, undesirable side effects are often observed ...together with enhanced electrochemical properties, leading to an unsatisfactory overall performance. In order to develop an anion doping strategy which enhances the positive effects and suppresses undesirable side effects, the understanding of their origin at the atomic scale is a crucial step. In this work, using density functional theory (DFT), we report a systematic study on the effects of three common anion dopants (F, S, Cl) on a wide range of properties of a model cathode material, LiNiO2, including redox potential, ionic conductivity, Li/Ni exchange, lattice distortion, and Ni migration upon delithiation. The results show that the dopants improve certain properties but worsen others, revealing some distance-dependent features. Overall, our work shows conflicting roles of anion doping on the battery voltage, rate performance, and structural stability of the cathode material. By identifying the origins of the different roles, we propose a rational anion doping strategy for the optimization of the overall electrochemical performance of the cathode material. These results for LiNiO2 can also promote anion doping studies and improved materials design in other Ni-rich layered oxide cathode materials.
High performance of electrocatalysts for direct methanol fuel cells was demonstrated by three-dimensional (3D) graphene (GR) decorated with platinum (Pt)–gold (Au) alloy nanoparticles (3D-GR/PtAu). ...The 3D-GR/PtAu composite with a morphology like a crumpled paper ball was synthesized from a colloidal mixture of GR and Pt–Au alloy nanoparticles with aerosol spray drying. The 3D-GR/PtAu had a high specific surface area and electrochemical surface area of up to 238 and 325m2/g(Pt), respectively, and the electrocatalytic applications of the 3D-GR/PtAu were examined through methanol oxidation reactions. The 3D-GR/PtAu had the highest electrocatalytic activity for methanol oxidation reactions compared with commercial Pt–carbon black and Pt-GR. The 3D-GR/PtAu was also highly sensitive electrocatalytic activity in the methanol oxidation reaction compared with the 2D-GR/Pt–Au. Furthermore, the electrocatalytic activity of the 3D-GR/PtAu had the highest performance among the catalysts containing Pt, Au, and GR for the methanol oxidation reactions. The increased electrocatalytic activity is attributed to the high specific surface area of the 3D formation and the effective surface structure of the Pt–Au alloy nanoparticles.
This study proposes a high-performance organic-inorganic hybrid memristor for the development of neuromorphic devices in the memristor-based artificial synapse. The memristor consists of a solid ...polymer electrolyte (SPE) chitosan layer and a titanium oxide (TiO
) layer grown with a low-thermal-budget, microwave-assisted oxidation. The fabricated Ti/SPE-chitosan/TiO
/Pt-structured memristor exhibited steady bipolar resistive switching (BRS) characteristics and demonstrated excellent endurance in 100-cycle repetition tests. Compared to SPE-chitosan memristors without a TiO
layer, the proposed organic-inorganic hybrid memristor demonstrated a higher dynamic range and a higher response to pre-synaptic stimuli such as short-term plasticity via paired-pulse facilitation. The effect of adding the TiO
layer on the BRS properties was examined, and the results showed that the TiO
layer improved the chemical and electrical superiority of the proposed memristor synaptic device. The proposed SPE-chitosan organic-inorganic hybrid memristor also exhibited a stable spike-timing-dependent plasticity, which closely mimics long-term plasticity. The potentiation and depression behaviors that modulate synaptic weights operated stably via repeated spike cycle tests. Therefore, the proposed SPE-chitosan organic-inorganic hybrid memristor is a promising candidate for the development of neuromorphic devices in memristor-based artificial synapses owing to its excellent stability, high dynamic range, and superior response to pre-synaptic stimuli.
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•A real-time anomaly detection method based on a convolutional neural network in wire arc additive manufacturing is presented.•A convolutional neural network-based model is created to ...detect balling and bead-cut defects with 98 % classification accuracy and 0.033 s/frame processing time.•Experiments are conducted using molybdenum material.•A prototype system is implemented to classify the current image data into normal and abnormal states.
Wire arc additive manufacturing (WAAM) has received attention because of its high deposition rate, low cost, and high material utilization. However, quality issues are critical in WAAM because it builds upon arc welding technology, which can result in low precision and poor quality of the melted parts. Hence, anomaly detection is essential for identifying abnormal behaviors and process instability during WAAM to reduce the time and cost of post-process treatment. The relevant studies have been conducted on anomaly detection algorithms using machine learning in fused deposition modeling and laser powder bed fusion; however, they have less investigated the implementation for in situ quality monitoring in WAAM. This work presents a real-time anomaly detection method that uses a convolutional neural network (CNN) in WAAM. The proposed method enables creation of CNN-based models that detect abnormalities by learning from the melt pool image data, which are pre-processed to increase learning performance. A prototype system was implemented to classify melt pool images into “normal” and “abnormal” states, with the latter accounting for balling and bead-cut defects. Experiments were conducted using molybdenum, a cost-intensive and hard-to-machine material. Four CNN-based models were created using MobileNetV2, DenseNet169, Resnet50V2, and InceptionResNetV2. Then, their performances were validated in terms of classification accuracy and processing time. The MobileNetV2 model yielded the best performance with 98 % of classification accuracy and 0.033 s/frame of processing time. This model was also compared with an object detection algorithm named “YOLO”, which yielded 73.5 % of classification accuracy and 0.067 s/frame of processing time.
Abstract
This study aims to investigate the difference in physiological loading on the spine in three different motions (flexion–extension, lateral bending, and axial rotation) between osteoporotic ...and normal spines, using finite element modelling. A three-dimensional finite element (FE) model centered on the lumbar spine was constructed. We applied two different material properties of osteoporotic and normal spines. For the FE analysis, three loading conditions (flexion–extension, lateral bending, and axial rotation) were applied. The von Mises stress was higher on the nucleus pulposus at all vertebral levels in all movements, in the osteoporosis group than in the normal group. On the annulus fibrosus, the von Mises stress increased at the level of L3–L4, L4–L5, and L5–S in the flexion–extension group and at L4–L5 and L5–S levels in the lateral bending group. The values of two motions, flexion–extension and lateral bending, increased in the L4 and L5 cortical bones. In axial rotation, the von Mises stress increased at the level of L5 of cortical bone. Additionally, the von Mises stress increased in the lower endplate of L5–S and L4–L5 in all movements, especially lateral bending. Even in the group with no increase, there was a part that received increased von Mises stress locally for each element in the three-dimensional reconstructed view of the pressure distribution in color. The von Mises stress on the lumbar region in the three loading conditions, was greater in most components of osteoporotic vertebrae than in normal vertebrae and the value was highest in the nucleus pulposus. Considering the increase in the measured von Mises stress and the local increase in the pressure distribution, we believe that these results can contribute to explaining discogenic pain and degeneration.
Abstract
Aim
This cross‐sectional study aimed to investigate the factors that affected the mental health of Korean nurses caring for coronavirus disease 2019 (COVID‐19) patients, causing ...posttraumatic stress disorder, depression, anxiety, and sleep disorders.
Background
Infectious disease outbreaks like COVID‐19 affect the mental health not only of those who contract the disease but also of nurses caring for affected patients.
Introduction
To address health issues effectively, it is essential to comprehend how to prevent them. Therefore, it is necessary to scrutinize the origins of COVID‐19–related health concerns and devise measures to prevent potential problems.
Method
We used an online survey to collect data from 136 nurses caring for COVID‐19 patients during the initial stage of the pandemic. The data were analyzed using the one‐way analysis of variance and a simple logistic regression.
Results
The findings confirmed a high prevalence of posttraumatic stress disorder among nurses, with symptoms of depression, anxiety, and sleep problems.
Discussion
Our research has shown that it is important not to exacerbate the difficulties that nurses face after their activities. Therefore, it proposes for creating environmental structures that mitigate predictable challenges such as workload from various tasks, sleep disturbances, and hopelessness, rather than focusing on personal vulnerabilities.
Conclusion
Timely attention to influencing factors can reduce the risk to nurses' mental health, so we need to plan preventive measures that reflect the influencing factors to prepare for future pandemics.
Implications for nursing and health policy
Continuous monitoring of the mental health status of nurses responding to a global health crisis and the development of appropriate psychological support programs and policies for creating a conducive work environment are necessary.
Reduced graphene oxide (RGO) is employed as a conductive binder for the unprecedentedly high performance of the used coffee grounds-derived AC (cAC) supercapacitor. The 2 wt% of RGO sheets in the cAC ...based electrode (cAC-2) successfully preserves high specific surface area of cAC and supports conductive networks decorated with oxygen groups, which synergistically improve charge storage capability. Furthermore, the wettability of the cAC-2 electrode enhanced by hydrophilic oxygen groups of RGO allows the easy access of the electrolyte to the pores of the electrode. The symmetric two electrode system exhibits outstanding charge storage capacity, reaching a high specific capacitance of 512 F g−1 in KOH electrolyte at 0.5 A g−1 which is nearly four times higher than that of cAC electrode with PVDF binders. Remarkable electrochemical performance is further demonstrated in EMIMTFSI electrolyte, including high specific capacitance of 440 F g−1 at 0.5 A g-1, with an excellent rate performance of 81.4% from 0.5 to 10 A g-1. The record high energy density of 187.3 Wh kg−1 is achieved at a power density of 438 W kg−1 and maintains an energy density of 153.8 Wh kg−1 at 8750 W kg−1 in EMIMTFSI electrolyte.
Novel-green electrode composed of biomass-derived activated carbons and RGO sheets as a binder was fabricated for ultrahigh performance supercapacitors. Display omitted
Mesenchymal stem cells (MSCs) exert their therapeutic capability through a variety of bioactive substances, including trophic factors, microRNAs, and extracellular vesicles (EVs) in infarcted ...tissues. We therefore hypothesized that MSC-derived EVs (MSC-EVs) possess therapeutic molecules similar to MSCs. Moreover, given their nature as nanosized and lipid-shielded particles, the intravenous infusion of MSC-EVs would be advantageous over MSCs as a safer therapeutic approach. In this study, we investigated the biodistribution, therapeutic efficacy, and mode of action of MSC-EVs in a rat stroke model. MSC-EVs successfully stimulated neurogenesis and angiogenesis in vivo. When compared to the MSC-treated group, rats treated with MSC-EVs exhibited greater behavioral improvements than the control group (
p
< 0.05). Our biodistribution study using fluorescence-labeled MSC-EVs and MSCs demonstrated that the amounts of MSC-EVs in the infarcted hemisphere increased in a dose-dependent manner, and were rarely found in the lung and liver. In addition, MSC-EVs were highly inclusive of various proteins and microRNAs (miRNAs) associated with neurogenesis and/or angiogenesis compared to fibro-EVs. We further analyzed those miRNAs and found that miRNA-184 and miRNA-210 were essential for promoting neurogenesis and angiogenesis of MSC-EVs, respectively. MSC-EVs represent an ideal alternative to MSCs for stroke treatment, with similar medicinal capacity but an improved safety profile that overcomes cell-associated limitations in stem cell therapy.
Stem cell-based therapy is a promising approach to repair brain damage after stroke. This study was conducted to investigate changes in neuroimaging measures using stem cell-based therapy in patients ...with ischemic stroke.
In this prospective, open-label, randomized controlled trial with blinded outcome evaluation, patients with severe middle cerebral artery territory infarct were assigned to the autologous mesenchymal stem cell (MSC) treatment or control group. Of 54 patients who completed the intervention, 31 for the MSC and 13 for the control groups were included in this neuroimaging analysis. Motor function was assessed before the intervention and 90 days after randomization using the Fugl-Meyer assessment scale. Neuroimaging measures included fractional anisotropy values of the corticospinal tract and posterior limb of the internal capsule from diffusion tensor magnetic resonance imaging and strength of connectivity, efficiency, and density of the motor network from resting-state functional magnetic resonance imaging.
For motor function, the improvement ratio of the Fugl-Meyer assessment score was significantly higher in the MSC group compared with the control group. In neuroimaging, corticospinal tract and posterior limb of the internal capsule fractional anisotropy did not decrease in the MSC group but significantly decreased at 90 days after randomization in the control group. Interhemispheric connectivity and ipsilesional connectivity significantly increased in the MSC group. Change in interhemispheric connectivity showed a significant group difference.
Stem cell-based therapy can protect corticospinal tract against degeneration and enhance positive changes in network reorganization to facilitate motor recovery after stroke. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01716481.
