The cooperative effect of electrochemical activation of electroplated nickel oxide and surface modification of APTES immobilization enabled the electrochemical detection of trace glutamate ...effectively.
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•NiOx is stably introduced onto the electrode surface through electroplating.•Electrochemical activation improves the electrocatalytic properties of NiOx.•APTES immobilized on the NiOx surface promotes interactions with glutamate.•The electrode achieves sensitive glutamate detection with a wide linear range.
The electrochemical behavior and catalytic properties of nickel oxide (NiOx) are enhanced through cathodic electroplating and subsequent electrochemical activation in an alkaline aqueous electrolyte. The electrochemical detection of ʟ-glutamate becomes feasible by introducing an amine group through immobilizing APTES ((3-aminopropyl)triethoxysilane) on the NiOx surface, resulting in a positive charge. The synergistic effect of electrochemically activated electroplated NiOx and the APTES-modified surface facilitates the effective electrochemical detection of trace ʟ-glutamate. The APTES-activated NiOx electrode exhibits a linear detection range of 0.2 nM to 2 mM for glutamate. This relatively wide concentration range is promising for the analysis of human biological fluids.
Physical and electrochemical features of nanoporous electrodes arising from their morphology are presented in this perspective. Although nanoporous electrodes have been used to enhance ...electrocatalysis for several decades, the origin of their capability was understood on the basis of enlarged surface area or crystalline facet. However, considerable attention should be paid to the fact that nano-confined space of nanoporous electrodes can significantly affect electrochemical efficiency. Molecular dynamics in nano-confined spaces is capable of offering much more chances of interaction between a redox molecule and an electrode surface. The mass transport in the nanoporous electrode depends on various pore characteristics such as size, shape, charge, connectivity, and symmetry as well as molecular properties such as size, charge, and kinetics. Moreover, when the pore size is comparable to the thickness of an electric double layer (EDL), the EDLs overlap in the porous structure so that electrochemically effective surface area is not the same as that of the real electrode surface. These unique properties come from simply nanoporous structure and suggest new opportunity to innovative electrocatalysts in the future.
NOD‐like receptor family protein 3 (NLRP3)‐mediated inflammasome activation promotes caspase‐1‐dependent production of interleukin‐1β (IL‐1β) and requires the adaptor protein ASC. Compared with the ...priming and activation mechanisms of the inflammasome signaling pathway, post‐translational ubiquitination/deubiquitination mechanisms controlling inflammasome activation have not been clearly addressed. We here demonstrate that the deubiquitinating enzyme USP50 binds to the ASC protein and subsequently regulates the inflammasome signaling pathway by deubiquitinating the lysine 63‐linked polyubiquitination of ASC. USP50 knockdown in human THP‐1 cells and mouse bone marrow‐derived macrophages shows a significant decrease in procaspase‐1 cleavage, resulting in a reduced secretion of IL‐1β and interleukin‐18 (IL‐18) upon treatment with NLRP3 stimuli and a reduction in ASC speck formation and oligomerization. Thus, we elucidate a novel regulatory mechanism of the inflammasome signaling pathway mediated by the USP50 deubiquitinating enzyme.
Magnetically assisted capsule endoscopy (MACE) showed the feasibility for upper gastrointestinal examination. To further enhance the performance of conventional MACE, it is necessary to provide ...quality-improved and three-dimensional images. The aim of this clinical study was to determine the efficacy and safety of novel three-dimensional MACE (3D MACE) for upper gastrointestinal and small bowel examination at once.
This was a prospective, single-center, non-randomized, and sequential examination study (KCT0007114) at Dongguk University Ilsan Hospital. Adult patients who visited for upper endoscopy were included. The study protocol was conducted in two stages. First, upper gastrointestinal examination was performed using 3D MACE, and a continuous small bowel examination was performed by conventional method of capsule endoscopy. Two hours later, an upper endoscopy was performed for comparison with 3D MACE examination. The primary outcome was confirmation of major gastric structures (esophagogastric junction, cardia/fundus, body, angle, antrum, and pylorus). Secondary outcomes were confirmation of esophagus and duodenal bulb, accuracy for gastric lesions, completion of small bowel examination, 3D image reconstruction of gastric lesion, and safety.
Fifty-five patients were finally enrolled. The examination time of 3D MACE was 14.84 ± 3.02 minutes and upper endoscopy was 5.22 ± 2.39 minutes. The confirmation rate of the six major gastric structures was 98.6% in 3D MACE and 100% in upper endoscopy. Gastric lesions were identified in 43 patients during 3D MACE, and 40 patients during upper endoscopy (Sensitivity 0.97). 3D reconstructed images were acquired for all lesions inspected by 3D MACE. The continuous small bowel examination by 3D MACE was completed in 94.5%. 3D MACE showed better overall satisfaction (3D MACE 9.55 ± 0.79 and upper endoscopy 7.75 ± 2.34, p<0.0001). There were no aspiration or significant adverse event or capsule retention in the 3D MACE examination.
Novel 3D MACE system is more advanced diagnostic modality than the conventional MACE. And it is possible to perform serial upper gastrointestinal and small bowel examination as a non-invasive and one-step test. It would be also served as a bridge to pan-endoscopy.
•Seawater is acidified to a pH of 2 while hydrogen evolution reaction (HER) occurs.•Interaction between inorganic precipitation and water dissociation of bipolar membrane.•Acidification of seawater ...reduces cathode potential for HER.•Formation of dispersed inorganic precipitates is suppressed by acidification.•Seawater acidification is an effective electrolyte engineering strategy for direct seawater electrolysis.
This report describes direct seawater electrolysis (DSE) wherein natural seawater is used as a catholyte without filtration or pretreatment; seawater is acidified to a pH of 2 while hydroxide ions are produced at the cathode by the hydrogen evolution reaction (HER). It results from the cooperative effect of hydroxide ions trapped through inorganic precipitation at the cathode and proton flux from water dissociation in a bipolar membrane (BPM; used as a separator). The acidification of the catholyte in the proposed BPM-DSE substantially mitigates cathode passivation, eliminates the requirement of additional processes for treatment of inorganic precipitates dispersed in the catholyte, and reduces the cathode potential (Ec) required for the HER to enable long-term DSE. The BPM in this system plays a critical role in maintaining the electrolyte concentration, suppressing the chlorine evolution reaction (ClER), and maximizing the oxygen evolution reaction. These findings are expected to suggest a breakthrough toward large-scale operation of DSE that successfully overcomes challenges such as energy consumption, inorganic precipitation, ClER, and corrosion.
Green means go: A polyelectrolyte diode on a microchip exhibits well-defined nonlinear rectifying behavior. This system visualizes the dynamic distribution of ions in a charged polymer phase under an ...electric field on a real-time basis using fluorescence images (see picture). Multiple polyelectrolyte diodes are integrated on a microchip to produce a variety of logic gates based on ionic circuits.
About 40-50% of patients with amnestic mild cognitive impairment (MCI) are found to have no significant Alzheimer's pathology based on amyloid PET positivity. Notably, conversion to dementia in this ...population is known to occur much less often than in amyloid-positive MCI. However, the relationship between MCI and brain amyloid deposition remains largely unknown. Therefore, we investigated the influence of subthreshold levels of amyloid deposition on conversion to dementia in amnestic MCI patients with negative amyloid PET scans.
This study was a retrospective cohort study of patients with amyloid-negative amnestic MCI who visited the memory clinic of Asan Medical Center. All participants underwent detailed neuropsychological testing, brain magnetic resonance imaging, and
F-florbetaben (FBB) positron emission tomography scan (PET). Conversion to dementia was determined by a neurologist based on a clinical interview with a detailed neuropsychological test or a decline in the Korean version of the Mini-Mental State Examination score of more than 4 points per year combined with impaired activities of daily living. Regional cortical amyloid levels were calculated, and a receiver operating characteristic (ROC) curve for conversion to dementia was obtained. To increase the reliability of the results of the study, we analyzed the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset together.
During the follow-up period, 36% (39/107) of patients converted to dementia from amnestic MCI. The dementia converter group displayed increased standardized uptake value ratio (SUVR) values of FBB on PET in the bilateral temporal, parietal, posterior cingulate, occipital, and left precuneus cortices as well as increased global SUVR. Among volume of interests, the left parietal SUVR predicted conversion to dementia with the highest accuracy in the ROC analysis (area under the curve AUC = 0.762, P < 0.001). The combination of precuneus, parietal cortex, and FBB composite SUVRs also showed a higher accuracy in predicting conversion to dementia than other models (AUC = 0.763). Of the results of ADNI data, the SUVR of the left precuneus SUVR showed the highest AUC (AUC = 0.596, P = 0.006).
Our findings suggest that subthreshold amyloid levels may contribute to conversion to dementia in patients with amyloid-negative amnestic MCI.
Geometric factors affecting the enhanced electrocatalysis on nanoporous Pt (L2-ePt) were examined by electrochemical methods and computer simulations. The experimental results revealed that the ...electrochemical enhancement of O2 and H2O2 does not come only from expansion of the active surface area (so-called roughness factor, f R) of L2-ePt. The presence of extra contribution was verified by the fact that significant enhancement in electrocatalytic reactions remained even after the effect of the f R was eliminated from the electrochemical redox behavior of O2 and H2O2 on L2-ePt electrodes. Not only the voltammetric observation but also potentiometric pH responses of L2-ePt suggested the presence of unique nanoporous effects other than the surface enlargement in regard to heterogeneous electrochemical reactions. L2-ePt showed near Nernstian behavior, faster response time, and less hysteresis even if the real surface area was smaller than that of flat Pt. Increased residence time near the electrode surface due to extremely confined space of nanoporous structure was proposed as possible origins and examined by the Monte Carlo simulations of simple model electrodes. The theoretical approaches indicated that long residence time of reactant at electrode surface by confinement effect of the nanoporous environment well accounted for the experimental results.
Meteorin‐like (metrnl) is a recently identified adipomyokine that beneficially affects glucose metabolism; however, its underlying mechanism of action is not completely understood. We here show that ...the level of metrnl increases in vitro under electrical pulse stimulation and in vivo in exercised mice, suggesting that metrnl is secreted during muscle contractions. In addition, metrnl increases glucose uptake via the calcium‐dependent AMPKα2 pathway in skeletal muscle cells and increases the phosphorylation of HDAC5, a transcriptional repressor of GLUT4, in an AMPKα2‐dependent manner. Phosphorylated HDAC5 interacts with 14‐3‐3 proteins and sequesters them in the cytoplasm, resulting in the activation of GLUT4 transcription. An intraperitoneal injection of recombinant metrnl improved glucose tolerance in mice with high‐fat‐diet‐induced obesity or type 2 diabetes, but not in AMPK β1β2 muscle‐specific null mice. Metrnl improves glucose metabolism via AMPKα2 and is a promising therapeutic candidate for glucose‐related diseases such as type 2 diabetes.
We found that metrnl, known as an adipomyokine, is secreted during muscle contractions. Metrnl increases glucose uptake via AMPKα in skeletal muscle cells and increases the phosphorylation of HDAC5 and TBC1D1 in AMPKα‐dependent manner. Recombinant metrnl improves glucose tolerance in mice with obesity or type 2 diabetes. These results suggest that metrnl is a promising therapeutic candidate for diabetes.
Mitochondrial dysfunction is a key element in the progression of Parkinson's disease (PD). The inefficient operation of the electron transport chain (ETC) impairs energy production and enhances the ...generation of oxidative stress contributing to the loss of dopaminergic cells in the brain. ATPase inhibitory factor 1 (IF1) is a regulator of mitochondrial energy metabolism. IF1 binds directly to the F
Fo ATP synthase and prevents ATP wasting during compromised energy metabolism. In this study, we found treatment with IF1 protects mitochondria against PD-like insult in vitro. SH-SY5Y cells treated with IF1 were resistant to loss of ATP and mitochondrial inner membrane potential during challenge with rotenone, an inhibitor of complex I in the ETC. We further demonstrated that treatment with IF1 reversed rotenone-induced superoxide production in mitochondria and peroxide accumulation in whole cells. Ultimately, IF1 decreased protein levels of pro-apoptotic Bax, cleaved caspase-3, and cleaved PARP, rescuing SH-SY5Y cells from rotenone-mediated apoptotic death. Administration of IF1 significantly improved the results of pole and hanging tests performed by PD mice expressing human α-synuclein. This indicates that IF1 mitigates PD-associated motor deficit. Together, these findings suggest that IF1 exhibits a neuroprotective effect preventing mitochondrial dysfunction in PD pathology.
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