High‐speed two‐photon microscopy can be used to analyze vascular dynamics in living animals and is essential for the understanding of brain diseases. Recent advances in fluorescent probes/optical ...systems have allowed successful imaging of the hippocampal vasculature in the deep brain of mice (1 mm from the brain surface) under low‐speed conditions (1–2 fps); however, using high‐speed techniques (>30 fps), observation of the deep‐brain vasculature is still challenging. Here, a new nanoemulsion that encapsulates thousands of red‐emissive pyrene dye molecules while maintaining their high two‐photon brightness 1.5 × 102 GM (GM = 10−50 cm4·s·photon−1·molecule−1) at 960 nm excitation and delivers a large amount of such pyrene dyes (65 nmol) into the blood vessels of mice is developed. Remarkably, the nanoprobe is found to exploit the inherent performance of a commonly used Ti:sapphire excitation laser and a sensitive gallium arsenide phosphide nondescanned fluorescence detector to the limit, enabling visualization of the brain vasculature under the cortex region of mice (up to 1.5 mm) under very low‐speed conditions. As a highlight, such a nanoprobe is successfully used to directly observe the blood flow in the hippocampal CA1 region (1.1 mm) through high‐speed resonant scanning (120 fps).
A novel dye‐loaded nanoemulsion is developed for high‐speed two‐photon microscopic imaging of the deep‐brain vasculature in mice. The nanoprobe delivers numerous bright pyrene dyes into the blood vessels of mice, fully exploiting the performance of a Ti:sapphire laser and a gallium arsenide phosphide detector. This approach allows the visualization of hippocampal blood flow in mice at above the video rate.
In article number 2010698, Yosuke Niko and co‐workers report a novel dye‐loaded nanoemulsion for high‐speed two‐photon microscopic imaging of the deep‐brain vasculature in mice. The nanoprobe fully ...exploits the performance of a Ti:sapphire laser and a gallium arsenide phosphide detector, allowing the visualization of hippocampal blood flow in mice at a high frame rate of 120 fps.
Since mitochondrial dysfunction was discovered to be the underlying cause of several severe diseases, fluorescent probes with excellent optical properties for visualising and monitoring the ...mitochondrial membrane potential (MMP) (a parameter of mitochondrial vitality) have been in high demand. Herein, we present novel pyrene-based dyes exhibiting remarkably large two-photon absorption around 900 nm and bright red emission around 620 nm (two-photon brightness (Φσ
) = 425-525 GM), with selective localisation to the mitochondria or nucleus in response to changes in the MMP, providing several advantages over traditional MMP-monitoring probes such as Rhodamine 123 (Φσ
= 64 GM). The intracellular behavior of the new dyes was investigated in detail. The driving forces for the dyes to dissociate from the mitochondria and migrate toward the nucleus upon decreasing the MMP were two key molecular characteristics: the dyes' permeability to mitochondrial membranes and their affinity to nuclear DNA. The results provide significant insights into improving the molecular design of the dyes.
Since mitochondrial dysfunction was discovered to be the underlying cause of several severe diseases, fluorescent probes with excellent optical properties for visualising and monitoring the ...mitochondrial membrane potential (MMP) (a parameter of mitochondrial vitality) have been in high demand. Herein, we present novel pyrene-based dyes exhibiting remarkably large two-photon absorption around 900 nm and bright red emission around 620 nm (two-photon brightness (
Φσ
2
) = 425-525 GM), with selective localisation to the mitochondria or nucleus in response to changes in the MMP, providing several advantages over traditional MMP-monitoring probes such as Rhodamine 123 (
Φσ
2
= 64 GM). The intracellular behavior of the new dyes was investigated in detail. The driving forces for the dyes to dissociate from the mitochondria and migrate toward the nucleus upon decreasing the MMP were two key molecular characteristics: the dyes' permeability to mitochondrial membranes and their affinity to nuclear DNA. The results provide significant insights into improving the molecular design of the dyes.
Pyrene-based two-photon active and bright red emitters that localize between the mitochondria and nucleus in response to changes in the mitochondrial membrane potential.
Three kind of isomers of xylene and ethylbenzene were analyzed using a gas chromatogrph-chemical ionization mass spectrometer with mass fragmentograhy technique to find any difference between these ...isomers in the various conditions, such as different reagent gases(CH4, i-C4H10 and NH3)and ion source temperature(200°C∼280°C). With iso-buthane as a reagent gas, the peak intensity of m/e 107(QM+)and the peak intensity ratio of m/e 106 to m/e 107 show remarkable differences between m-xylene and the other isomers at 200°C of the ion source temperature, and the differences decrease with increasing temperature. With ammonia as a reagent gas, the peak intensity of m/e 106 and the peak intensity ratio of m/e 108 to m/e 106 show much differences between p-xylene and the other isomers, and the differences are unchanged by the ion source temperature 200°∼280°C. Peak intensity ratio of m/e 105 to m/e 107 of ethylbenzene is much higher than the one of xylene isomers with iso-buthane as a reagent gas at 200°C of ion source temperature, and the differences decrease with increasing temperature.
Three kinds of isomers of cresol trimethylsilyl ethers were analyzed using a gas chromatograph-chemical ionization mass spectrometer with mass fragmentography technique to find any difference between ...these isomers in various conditions, such as reagent gases(anmonia, methane and iso-butane)and the ion source temperature(200°C∼290°C). With anmonia as a reagent gas, the peak intensity ratios of m/e 180 to m/e 181 show remarkable differences between m-, o-and p-cresol trimethylsilyl ethers at 290°C of the ion source temperature.
The construction and performances of a dual EI/CI ion source designed for the Shimadzu GCMS-9000 are described. Some design considerations on the construction of the combined gaschromatograph-EI/CI ...mass spectrometer are also described. Among various operating parameters for chemical ionization, ion source temperature has noticeable effects on CI spectra. Several measurements on temperature effect were carried out. As CI spectra are generally simpler and have greater abundance of quasi molecular ion than EI spectra, it is favourable to detect trace amount of sample with mass frag-mentography technique. Typical example which will show the minimum detectable amount is also shown. It is possible with this source to measure various mass spectra such as EI, CI, CE and combined CE/CI spectra of the same sample. Examples of such spectra data are presented.
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