Sensing of acetone by Al-doped ZnO Yoo, Ran; Güntner, Andreas T.; Park, Yunji ...
Sensors and actuators. B, Chemical,
03/2019, Volume:
283
Journal Article
Peer reviewed
•ZnO nanoparticle (NP)-based sensors for detecting hazardous gas, acetone is presented.•ZnO NPs are synthesized by flame spray pyrolysis and doped with Al to enhance sensing performance.•The sensor ...based on these particles shows an outstanding sensing performance.•The enhanced sensing is mainly due to the synergetic effect of oxygen vacancy, optical bandgap, specific surface area.
The development of chemoresistive gas sensors for environmental and industrial air monitoring as well as medical breath analysis is investigated. Flame-made ZnO nanoparticles (NPs) doped with 1 at% Aluminum exhibited higher sensing performance (response 245, response time ∼ 3 s, and sensitivity 23 ppm−1) than pure ZnO and those made by a hydrothermal method (HT) (56, ∼ 12 s, and 4 ppm−1) for detection of 10 ppm acetone. Furthermore, their sensing response of ∼10 to 0.1 ppm of acetone at 90% RH is superior to other metal oxide sensors and they feature good acetone selectivity to other compounds (including NH3, isoprene and CO). Characterization by N2 adsorption, X-ray photoelectron and UV–vis spectroscopies reveals that the improved sensing performance of flame-made Al-doped ZnO NPs is associated primarily to a higher density of oxygen vacancies than pure ZnO and all HT-made NPs. This leads to a greater number of adsorbed oxygen ions on the surfaces of Al-doped ZnO NPs, which can react with acetone molecules.
The gut microbiome has been known to contribute up to ~30% of the energy absorption of the host. Although various beneficial mechanisms of probiotics have been suggested for non-alcoholic fatty liver ...disease (NAFLD), whether and which probiotics impact the host's intestinal energy absorption have not yet been quantitatively studied. Here, we suggest a novel mechanism of probiotics against NAFLD, in which Lactobacillus rhamnosus GG, the most common probiotic, shares intestinal fatty acids and prevents the development of diet-induced hepatic steatosis. By using quantitative methods (radioactive tracers and LC-MS) under both in vitro and in vivo conditions, we found that bacteria and hosts competed for fatty acid absorption in the intestine, resulting in decreased weight gain, body fat mass, and hepatic lipid accumulation without differences in calorie intake and excretion in mice fed the probiotic bacteria.
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The gas sensing properties of Al-doped ZnO nanoparticles (NPs), which were synthesized via a hydrothermal method, have been described for the detection of volatile organic compounds ...(VOCs) such as acetaldehyde, toluene, and benzene. The maximum sensing response (R = 2250) of these Al-doped ZnO NPs was observed upon exposure to 10 ppm acetaldehyde at an optimal operating temperature of 500 °C, which was almost 173 and 125 times higher than that observed for toluene and benzene, respectively. The highest dipole moment of acetaldehyde among the three VOCs is responsible for its highest sensitivity. The Al-doped ZnO NPs also show a higher selectivity toward acetaldehyde than that of different interfering gases and their response to acetaldehyde was superior compared with the previously reported responses of other materials. The enhanced sensing performance of Al-doped ZnO NPs to acetaldehyde compared to undoped ones may be explained by an increase in specific surface area, oxygen vacancies, and conductivity after Al doping.
Skeletal muscle is a major organ for glucose disposal and thermogenesis. While hepatic fructose-1,6-bisphosphatase is well known as a key enzyme for gluconeogenesis, the role of muscle ...fructose-1,6-bisphosphatase 2 (Fbp2) in glucose disposal and thermogenesis is unknown. Here, using Fbp2 knockout (KO) mice, we assessed the physiological role of Fbp2 in energy and glucose metabolism and thermogenesis. In vivo assessments of energy metabolism, glucose metabolism, and thermogenesis were performed by indirect calorimetry, hyperinsulinemic-euglycemic clamp, and cold challenge studies, respectively. Under both feeding and fasting conditions, Fbp2 KO mice showed similar phenotypes regarding energy and glucose metabolism compared to wild-type (WT) mice. However, Fbp2 KO mice were severely intolerant to cold challenge under fasting conditions. Mechanistically, the cold-induced intramuscular conversion of lactate to glycogen (glyconeogenesis) is completely abolished in the KO muscle, which leads to a lack of glycogen source for thermogenesis in Fbp2 KO mice. The cold-intolerant phenotype of KO mice disappeared after feeding, and the KO mice were equally as cold tolerant as the WT mice and survived during the cold challenge for three weeks. Taken together, these data demonstrate that Fbp2 is essential for muscle thermogenesis by replenishing the intramuscular glycogen pool through glyconeogenesis when the exogenous glucose source is limited. These data imply the physiological importance of Fbp2 in thermal homeostasis and suggest a potential novel therapy targeted to increase glycogen replenishment upon cold stress.
Controlling the generation of secondary phases in thermoelectric higher manganese silicides is crucial to enhance their thermoelectric performance for use in automotive thermoelectric generators. ...However, the effect of different synthesis and sintering procedures on the secondary phase formation and thermoelectric properties has not yet been investigated. In this study, we demonstrate that fabricating Mn11Si19 via arc melting and spark plasma sintering results in a figure of merit (ZT) of 0.43 at 823 K, which is 15% higher than for a sample fabricated by a solid-state reaction and spark plasma sintering. We found that the presence of secondary MnSi phases in the Mn11Si19 samples was significantly reduced when using arc melting instead of solid-state reaction, which suggests that the phase formation behavior could be controlled by optimizing the fabrication process.
We prepared Sn nanoparticle-embedded Mg1.96Al0.04Si0.97Bi0.03 nanocomposites and measured their thermoelectric properties and fracture toughness to elucidate the trade-off relationship between ...thermoelectric and mechanical properties. When Sn nanoparticles (50–150 nm) were introduced at the grain boundaries of the thermoelectric Mg1.96Al0.04Si0.97Bi0.03 matrix, the fracture toughness improved because of the inhibition of crack propagation. However, the power factor deteriorated due to the decrease in carrier mobility. We found that interface (between thermoelectric matrix and nanoparticles) density is a critical factor to determine the mechanical properties as well as thermoelectric transport properties. Optimized values of figure of merit (∼0.66 @ 873 K) and fracture toughness (1.10 MPa m1/2) were obtained for 0.9 vol % Sn nanoparticle-embedded Mg1.96Al0.04Si0.97Bi0.03 nanocomposite.
•We prepared nanocomposites by nanometal decoration and SPS.•The importance of interface density for improving TE and mechanical properties.•The effect of the grain growth inhibition by Sn nanoparticles.•Improved fracture toughness was obtained due to inhibiting crack propagation.•The importance of precisely controlled nanophase design and synthesis process.
Pulmonary thromboembolism (PTE) is rarely reported in Behçet's disease (BD) due to its distinctive thrombus‐forming mechanism. In BD, the inflammation on vessel walls causes venous thrombosis. The ...thrombi are considered to be tethered to the inflamed walls making embolization less frequent. Thus, immunosuppressive agents are the mainstay of treatment. However, the necessity of anticoagulation therapy is controversial because of its uncertain efficacy of resolving thrombi and the possibility of fatal side effects of hemorrhage. A 25‐year‐old man with recurrent oral aphthae visited with abrupt onset of dyspnea and chest pain. Based on history, imaging studies and laboratory results, he was diagnosed with BD with vascular involvement and antiphospholipid syndrome (APS), causing PTE from deep vein thrombosis. The co‐existing APS may have further promoted the thrombosis, shifting his blood profile toward the hypercoagulable state. Immunosuppressive therapy with glucocorticoid and azathioprine, and concomitant anticoagulation with warfarin were achieved successfully without any fatal complications. When atypical features of vascular involvement in BD develop, other coexisting diseases should be considered to design an optimal therapeutic plan.
The unripe fruits of Rubus coreanus (Rosaceae) are used in traditional Chinese medicine to relieve kidney dysfunction. In the present study, we evaluated the protective effects of the triterpenoid ...glycoside niga-ichigoside F1 (NIF1) and of its aglycone 23-hydroxytormentic acid (23-HTA) isolated from the unripe fruits of Rubus coreanus (Rosaceae) against cisplatin-induced cytotoxicity in renal epithelial LLC-PK1 cells. Pretreating LLC-PK1 cells with 23-HTA or NIF1 was found to prevent cisplatin-induced cytotoxicity and apoptosis. In addition, 23-HTA or NIF1 pretreatment significantly improved the changes associated with cisplatin toxicity by increasing levels of glutathione (GSH) and decreasing levels of malondialdehyde (MDA) and reactive oxygen species (ROS). The activity of antioxidant enzymes including catalase (CAT) and superoxide dismutase (SOD) was significantly lower in cisplatin-treated LL-PK1 cells, and 23-HTA or NIF1 treatment notably increased the these enzyme activity and protein and mRNA levels of CAT and manganese SOD (MnSOD). Moreover, cisplatin caused a significant decrease in nuclear levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and pretreatment with 23-HTA or NIF1 significantly suppressed the cisplatin-induced translocation of Nrf2 in LLC-PK1 cells. Taken together, these results suggest that 23-HTA ameliorates cisplatin-induced toxicity via modulation of antioxidant enzymes through activation of Nrf2 in LLC-PK1 cells.
This study aimed to predict the composition of urolithiasis using deep learning from urinary stone images.
We classified 1,332 stones into 31 classes according to the stone composition. The top 4 ...classes with a frequency of 110 or more (class 1: calcium oxalate monohydrate COM 100%, class 2: COM 80%+struvite 20%, class 3: COM 60%+calcium oxalate dihydrate COD 40%, class 4: uric acid 100%) were selected. With the 965 stone images of the top 4 classes, we used the seven convolutional neural networks (CNN) to classify urinary stones and compared their classification performances.
Among the seven models, Xception_Ir0.001 showed the highest accuracy, precision, and recall and was selected as the CNN model to predict the stone composition. The sensitivity and specificity for the 4 classes by Xception_Ir0.001 were as follows: class 1 (94.24%, 91.73%), class 2 (85.42%, 96.14%), class 3 (86.86%, 99.59%), and class 4 (94.96%, 98.82%). The sensitivity and specificity of the individual components of the stones were as follows. COM (98.82%, 94.96%), COD (86.86%, 99.64%), struvite (85.42%, 95.59%), and uric acid (94.96%, 98.82%). The area under the curves for class 1, 2, 3, and 4 were 0.98, 0.97, 1.00, and 1.00, respectively.
This study showed the feasibility of deep learning for the diagnostic ability to assess urinary stone composition from images. It can be an alternative tool for conventional stone analysis and provide decision support to urologists, improving the effectiveness of diagnosis and treatment.
During mitosis, regulation of protein structures and functions by phosphorylation plays critical roles in orchestrating a series of complex events essential for the cell division process. ...Tumor-associated microtubule-associated protein (TMAP), also known as cytoskeleton-associated protein 2 (CKAP2), is a novel player in spindle assembly and chromosome segregation. We have previously reported that TMAP is phosphorylated at multiple residues specifically during mitosis. However, the mechanisms and functional importance of phosphorylation at most of the sites identified are currently unknown. Here, we report that TMAP is a novel substrate of the Aurora B kinase. Ser627 of TMAP was specifically phosphorylated by Aurora B both in vitro and in vivo. Ser627 and neighboring conserved residues were strictly required for efficient phosphorylation of TMAP by Aurora B, as even minor amino acid substitutions of the phosphorylation motif significantly diminished the efficiency of the substrate phosphorylation. Nearly all mutations at the phosphorylation motif had dramatic effects on the subcellular localization of TMAP. Instead of being localized to the chromosome region during late mitosis, the mutants remained associated with microtubules and centrosomes throughout mitosis. However, the changes in the subcellular localization of these mutants could not be completely explained by the phosphorylation status on Ser627. Our findings suggest that the motif surrounding Ser627 (
625
RRSRRL
630
) is a critical part of a functionally important sequence motif which not only governs the kinase-substrate recognition, but also regulates the subcellular localization of TMAP during mitosis.
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