PLoS One
·
2015
·Vol. 10
·期 10
·e0140560
·
IF 3.234
Paul Kyu Han,Jeffrey W. Barker,Ki Hwan Kim,Seung Hong Choi,Kyongtae Ty Bae,Sung-Hong Park
The recent blood flow and magnetization transfer (MT) technique termed alternate ascending/descending directional navigation (ALADDIN) achieves the contrast using interslice blood flow and MT effects with no separate preparation RF pulse, thereby potentially overcoming limitations of conventional methods. In this study, we examined the signal characteristics of ALADDIN as a simultaneous blood flow and MT imaging strategy, by comparing it with pseudo-continuous ASL (pCASL) and conventional MT asymmetry (MTA) methods, all of which had the same bSSFP readout. Bloch-equation simulations and experiments showed ALADDIN perfusion signals increased with flip angle, whereas MTA signals peaked at flip angle around 45°−60°. ALADDIN provided signals comparable to those of pCASL and conventional MTA methods emulating the first, second, and third prior slices of ALADDIN under the same scan conditions, suggesting ALADDIN signals to be superposition of signals from multiple labeling planes. The quantitative cerebral blood flow signals from a modified continuous ASL model overestimated the perfusion signals compared to those measured with a pulsed ASL method. Simultaneous mapping of blood flow, MTA, and MT ratio in the whole brain is feasible with ALADDIN within a clinically reasonable time, which can potentially help diagnosis of various diseases.
研究领域:
医学影像
·
神经影像
·
磁共振成像 (MRI)
·
生物医学工程
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF LUMINESCENCE
·
2024
·
IF 3.3
Zhenggang Zou,Jiawei Zhu,Fulin Lin,Yijian Sun,Jianhui Huang,Jinsheng Liao,Guoliang Gong,Herui Wen
The development of Eu 2+ -activated oxide materials with high efficiency, fast decay and narrow bandwidth emission in the visible region is still challenging for the field of luminescence and scintillation applications. Generally, Eu 2+ in oxide hosts can emit intense and broad 5d-4f emission in the visible region, but efficient emitting with stable bivalence of Eu is rare in inorganic oxide system. In this work, a series of ASL:Eu 2+ (Sr 1-x La x Mg x Al 12-x O 19 ) powder samples with various La, Mg doping ratios were designed and synthesized to modulate the UV or X-ray excited luminescence properties , including redshift, quantum yield , and decaying lifetime. Moreover, an ASL:Eu 2+ crystal with the optimal ratio x = 1/3 was grown, its scintillation performance was compared with standard Bi 4 Ge 3 O 12 crystal sample and evaluated in detail. These results indicate that the ASL:Eu 2+ crystal is potential scintillator as a kind of X-ray detection and provide a reference for the further development of high-performance Eu-activated oxide scintillation materials.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Science Letters
·
2012
·Vol. 10
·期 1
·367-370
·
IF 0
Wang Jiqing,Wu Mingming,Hou Qinglin,Tan Ying
The silica particles were prepared by chemical precipitation method using silicon tetrachloride and sodium silicate as silica precursor. The amino-functionalized silica particles were obtained via surface (3-aminopropyl) triethoxysilane (APTES) modification. Samples including silica
and amino-functionalized silica were characterized by transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. Amino-modified silica particles were used to extract free fatty acid from camellia oil based on the reaction between amino groups and carboxyl groups.
Extraction conditions were studied through the change of acid value of the camellia oil. The results demonstrated that amino-modified silica particles could react with free fatty acid in camellia oil, which can serve the purpose of decreasing acid value and improve the quality of camellia
oil.
研究领域:
化学工程
·
食品科学
✓ 已验证
DOI
Advanced Science Letters
·
2012
·Vol. 10
·期 1
·274-278
·
IF 0
Liu Chenglu,Wang Fang,Zhou Zhiqiang,Jia Peiyun
YNbO4:Eu nano-phosphors were successfully prepared in NaNO3 molten salt. X-ray diffraction was used to characterize the structure of the samples. The results indicate that a suitable amount of NaOH in NaNO3 molten salt can effectively improve the crystallinity
of the samples annealed at same temperature; meanwhile, the elevation of annealing temperature increases the crystallinity, and transfers the crystalline phase from scheelite to fergusonite. The micrographs of transmission electron microscopy reveal that the grain size increases with the elevation
of annealing temperature. Upon excitation into the niobate groups at 260 nm, YNbO4:Eu nano-phosphors exhibit weak emission at 405 nm, originated from Nb–O charge transfer transition and the characteristic emission of Eu3+, which indicates there is an energy transfer
from niobate group to Eu3+. Monitored by emission of 615 nm, the excitation spectrum shows that the f-f transition of 7F0–5L6 at 396 nm is more intense than the Nb–O charge transfer band at 260 nm. This intense absorption at
396 nm make YNbO4:Eu nano-phosphors an excellent candidate of white light emitting diode.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
Advanced Science Letters
·
2013
·Vol. 19
·期 4
·1226-1228
·
IF 0
Chao Guoku,Shao Lianping,Yao Shuai,Hong Liming,Li Dashuai,Xiong Jing
7 Aza-Michael adducts, 3-(5-substituted-2,4-dioxo-3,4-dihydro-2H-pyrimidin-1-yl)-propionic acid ethyl esters were synthesized by 5-subtituted uracils and ethyl acrylate with ammonia as a catalyst. It was significant that the synthetic compounds were collected in almost quantitive yields
without column chromatography. The structures of the compounds were determined by NMR, mass spectra, X-ray crystallography analyses and elemental analyses.
研究领域:
有机化学
·
药物化学
·
杂环化学
·
合成方法学
✓ 已验证
DOI
Nature Plants
·
2023
·
IF 18
Xie Yuanming,Lv Yuanda,Jia Letian,Zheng Lulu,Li Yonghui,Zhu Ming,Tian Mengjun,Wang Ming,Qi Weicong,Luo Long,De Gernier Hugues,Pélissier Pierre-Mathieu,Motte Hans,Lin Shaoyan,Luo Le,Xu Guohua,Beeckman Tom,Xuan Wei
Ammonium toxicity affecting plant metabolism and development is a worldwide problem impeding crop production. Remarkably, rice ( Oryza sativa L.) favours ammonium as its major nitrogen source in paddy fields. We set up a forward-genetic screen to decipher the molecular mechanisms conferring rice ammonium tolerance and identified rohan showing root hypersensitivity to ammonium due to a missense mutation in an argininosuccinate lyase (ASL)-encoding gene. ASL localizes to plastids and its expression is induced by ammonium. ASL alleviates ammonium-inhibited root elongation by converting the excessive glutamine to arginine. Consequently, arginine leads to auxin accumulation in the root meristem, thereby stimulating root elongation under high ammonium. Furthermore, we identified natural variation in the ASL allele between japonica and indica subspecies explaining their different root sensitivity towards ammonium. Finally, we show that ASL expression positively correlates with root ammonium tolerance and that nitrogen use efficiency and yield can be improved through a gain-of-function approach.
研究领域:
植物科学
·
分子生物学
·
农业
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）