| 1. |
- Nguyen Van, Toan, et al.
(författare)
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Fabrication of highly sensitive and selective H2 gas sensor based on SnO2 thin film sensitized with microsized Pd islands
- 2016
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Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 0304-3894 .- 1873-3336. ; 301, s. 433-442
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Tidskriftsartikel (refereegranskat)abstract
- Ultrasensitive and selective hydrogen gas sensor is vital component in safe use of hydrogen that requires a detection and alarm of leakage. Herein, we fabricated a H2 sensing devices by adopting a simple design of planar–type structure sensor in which the heater, electrode, and sensing layer were patterned on the front side of a silicon wafer. The SnO2 thin film–based sensors that were sensitized with microsized Pd islands were fabricated at a wafer–scale by using a sputtering system combined with micro–electronic techniques. The thicknesses of SnO2 thin film and microsized Pd islands were optimized to maximize the sensing performance of the devices. The optimized sensor could be used for monitoring hydrogen gas at low concentrations of 25–250 ppm, with a linear dependence to H2 concentration and a fast response and recovery time. The sensor also showed excellent selectivity for monitoring H2 among other gases, such as CO, NH3, and LPG, and satisfactory characteristics for ensuring safety in handling hydrogen. The hydrogen sensing characteristics of the sensors sensitized with Pt and Au islands were also studied to clarify the sensing mechanisms.
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| 2. |
- Bentham, James, et al.
(författare)
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A century of trends in adult human height
- 2016
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Ingår i: eLIFE. - 2050-084X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.522.7) and 16.5 cm (13.319.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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| 3. |
- Bentham, James, et al.
(författare)
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A century of trends in adult human height
- 2016
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3– 19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8– 144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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| 4. |
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| 5. |
- Duyen, Nguyen Thi, et al.
(författare)
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Steroid glycosides isolated from Paris polyphylla var. chinensis aerial parts and paris saponin II induces G1/S-phase MCF-7 cell cycle arrest
- 2022
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Ingår i: Carbohydrate Research. - : Elsevier BV. - 0008-6215. ; 519
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Tidskriftsartikel (refereegranskat)abstract
- In our previous research on Vietnamese medicinal plants, we found that the ethanolic extract of the aerial parts of Paris polyphylla var. chinensis exhibited cytotoxic effects in vitro in the MCF-7 human cancer cell line. Here, we used combined chromatographic separations to isolate six compounds including a new steroid glycoside, paripoloside A (3), and five known compounds, from the butanol extract of the aerial parts of P. polyphylla. We unambiguously elucidated their structures based on spectroscopic data (proton and carbon-13 nuclear magnetic resonance, heteronuclear single quantum coherence, heteronuclear multiple bond correlation, correlation spectroscopy, and high-resolution electrospray ionization mass spectroscopy data), and chemical reactions. Among the isolated compounds, paris saponin II (PSII) had the strongest cytotoxic effects against MCF-7 breast cancer cells. Interestingly, PSII significantly increased the expression of p53, p21, p27, and Bax protein levels and significantly suppressed the expression of cyclin D1 and retinoblastoma protein. These data suggest that PSII may induce G1/S phase cell cycle arrest and apoptosis pathway development in MCF-7 cells. Furthermore, the MCF-7 breast cancer cells mechanism of PSII was also investigated using molecular docking. Together, our results demonstrate that isolated compounds from P. polyphylla are promising candidates as breast cancer inhibitors.
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| 6. |
- Jiao, Mingzhi, et al.
(författare)
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Comparison of NO2 Gas-Sensing Properties of Three Different ZnO Nanostructures Synthesized by On-Chip Low-Temperature Hydrothermal Growth
- 2018
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Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 0361-5235 .- 1543-186X. ; 47:1, s. 785-793
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Tidskriftsartikel (refereegranskat)abstract
- Three different ZnO nanostructures, dense nanorods, dense nanowires, and sparse nanowires, were synthesized between Pt electrodes by on-chip hydrothermal growth at 90°C and below. The three nanostructures were characterized by scanning electron microscopy and x-ray diffraction to identify their morphologies and crystal structures. The three ZnO nanostructures were confirmed to have the same crystal type, but their dimensions and densities differed. The NO2 gas-sensing performance of the three ZnO nanostructures was investigated at different operation temperatures. ZnO nanorods had the lowest response to NO2 along with the longest response/recovery time, whereas sparse ZnO nanowires had the highest response to NO2 and the shortest response/recovery time. Sparse ZnO nanowires also performed best at 300°C and still work well and fast at 200°C. The current–voltage curves of the three ZnO nanostructures were obtained at various temperatures, and the results clearly showed that sparse ZnO nanowires did not have the linear characteristics of the others. Analysis of this phenomenon in connection with the highly sensitive behavior of sparse ZnO nanowires is also presented.
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| 7. |
- Jiao, Mingzhi, et al.
(författare)
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Influence of annealing temperature on the performance of on-chip hydrothermally grown ZnO nanorod gas sensor toward NO2
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Nanorod-based gas sensors synthesized at low temperature should generally be annealed before usage. However, the influence of annealing on the sensing performance of these nanorods is rarely reported. In this study, we first fabricated gas sensors based on ZnO nanorods grown on-chip on glass substrate using hydrothermal method. Subsequently, these sensors were annealed at either 400 °C, 500 °C, or 600 °C in air for 4 h. The gas-sensing performance of the ZnO nanorods toward NO2 was tested before and after annealing. The sensitivity of the gas sensors to NO2 decreased, but the stability increased with the increase in annealing temperature. Photoluminescence spectroscopy and X-ray diffraction were used to investigate the material structure of ZnO nanorods. Results revealed that the oxygen-atom-related defects in the ZnO lattice in the region close to the surface influenced by annealing process were the most significant factors on the sensing properties and stability of ZnO nanorods.
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| 8. |
- Jiao, Mingzhi, et al.
(författare)
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Influence of annealing temperature on theperformance and stability of on-chip hydrothermally grown ZnO nanorod gassensor toward NO2
- 2018
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Ingår i: Academia Journal of Scientific Research. - 2315-7712. ; 6:5, s. 180-189
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Tidskriftsartikel (refereegranskat)abstract
- Nanorod-based gas sensors synthesized at low temperature should generally be stabilized by anneling before usage. However, the influence of annealing on the sensing performance and stability of these nanorods is rarely reported. In this study, we first fabricated gas sensors based on ZnO nanorods grown on-chip on glass substrate using hydrothermal method. Subsequently, these sensors were annealed at either 400 °C, 500 °C, or 600 °C in air for 4 h. The gas-sensing performance of the ZnO nanorods toward NO2 was tested before and after annealing. The sensitivity of the gas sensors to NO2 decreased, but the stability increased with the increase in annealing temperature. Photoluminescence spectroscopy and X-ray diffraction were used to investigate the material structure of ZnO nanorods. Results revealed that the oxygen-atom-related defects in the ZnO lattice in the region close to the surface influenced by annealing process were the most significant factors on the sensing properties and stability of ZnO nanorods.
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| 9. |
- Jiao, Mingzhi, et al.
(författare)
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On-chip growth of patterned ZnO nanorod sensors with PdO decoration for enhancement of hydrogen-sensing performance
- 2017
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 42:25, s. 16294-16304
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we used a low-temperature hydrothermal technique to fabricate arrays of sensors with ZnO nanorods grown on-chip. The sensors on the glass substrate then were sputter decorated with Pd at thicknesses of 2, 4, and 8 nm and annealed at 650 °C in air for an hour. Scanning electron microscopy, high resolution transmission microscopy, X-ray diffraction, and surface analysis by X-ray photoelectron spectroscopy characterization demonstrated that decoration of homogenous PdO nanoparticles on the surface of ZnO nanorods had been achieved. The sensors were tested against three reducing gases, namely hydrogen, ethanol, and ammonia, at 350, 400, and 450 °C. The ZnO nanorods decorated with PdO particles from the 2 and 4 nm layers showed the highest responses to H2 at 450 and 350 °C, respectively. These samples also generally exhibited better selectivity for hydrogen than for ethanol and ammonia at the same concentrations and at all tested temperatures. However, the ZnO nanorods decorated with PdO particles from the 8 nm layer showed a reverse sensing behaviour compared with the first two. The sensing mechanism behind these phenomena is discussed in the light of the spillover effect of hydrogen in contact with the PdO particles as well as the negative competition of the PdO thin film formed between the sensor electrodes during sputter decoration, Pd-Zn heterojunction that forms at high temperature and thus influences the conductivity of the ZnO nanorods.
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| 10. |
- Jiao, Mingzhi, et al.
(författare)
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On-chip hydrothermal growth of ZnO nanorods at low temperature for highly selective NO2 gas sensor
- 2016
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Ingår i: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 169, s. 231-235
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Tidskriftsartikel (refereegranskat)abstract
- ZnO nanorods were selectively grown on-chip with a two-step low-temperature hydrothermal method and their gas sensing properties were investigated. Small zinc islands were deposited by sputtering on a glass substrate and used as nucleation sites for the ZnO nanorod growth. An equimolar aqueous solution of 0.005 M Zn(NO3)(2)center dot 6H(2)O and (CH2)(6)N-4 at 85 center dot C was used in two steps. The first step was used for nucleation and growth of short ZnO nanorods for 4 h, whereas the second step was used for elongation of the nanorods for 36 h. Long porous nanorods from neighboring islands connected to each other and formed nanorod junctions. A gas sensor with such nanorods was evaluated towards NO2, ethanol, hydrogen, and ammonia to characterize its sensing properties. It showed that the gas sensor has the highest sensitivity to NO2, and a very high selectivity to this gas when measured at 450 degrees C.
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