A method of aerosol introduction for matrix-assisted laser desorption/ionization （MALDI） is described. The aerosol particles containing matrix and analyte enter directly into the aerosol time-of-flight mass spectrom...A method of aerosol introduction for matrix-assisted laser desorption/ionization （MALDI） is described. The aerosol particles containing matrix and analyte enter directly into the aerosol time-of-flight mass spectrometer （ATOFMS） at atmospheric pressure. The scattered light signals from the aerosol particles are collected by a photomultiplier tube （PMT） and are passed on to an external electronic timing circuit, which determines particle size and is used to trigger a 266 nm pulsed Nd：YAG laser. The aerosol MALDI mass spectra and aerodynamic diameter of single particles can be obtained in real-time. Compared with other methods of liquid sample introduction, this method realizes detection of single particles and, more importantly, the sample consumption is lower. The effects of matrix-to-analyte ratio and laser pulse energy on analyte ion yield are examined. The optimal matrix-to-analyte ratio and laser energy are 50-110：1 and 200-400μl respectively.展开更多
We demonstrate that, by undersampling scanning object with a reconstruction algorithm related to compressed sensing, an image with the resolution exceeding the finest resolution defined by the numerical aperture of th...We demonstrate that, by undersampling scanning object with a reconstruction algorithm related to compressed sensing, an image with the resolution exceeding the finest resolution defined by the numerical aperture of the system can be obtained. Experimental results show that the measurements needed to achieve sub-Rayleigh resolution enhancement can be less than 10% of the pixels of the object. This method offers a general approach applicable to point-by-point illumination super-resolution techniques.展开更多
（~）-Calanolide A was the first natural product identified as an active agent against HIV-1 and Mycobacterium tuberculosis （Mtb）. In devising a scaffold-hopping strategy of structure modification of （＋）-calanoli...（~）-Calanolide A was the first natural product identified as an active agent against HIV-1 and Mycobacterium tuberculosis （Mtb）. In devising a scaffold-hopping strategy of structure modification of （＋）-calanolide A, we focused on the synthesis of calanolides by replacing ring D with various five or six membered nitrogen-containing heterocycles, hoping to get further understanding of the structure- activity relationship.展开更多
We have explored the chemistry of N-oxide heterocycles and imidazoles replacing ring D of the natural product（＋）-calanolide A, and have synthesized 12 new analogues, two of which were active against both R Mtb and ...We have explored the chemistry of N-oxide heterocycles and imidazoles replacing ring D of the natural product（＋）-calanolide A, and have synthesized 12 new analogues, two of which were active against both R Mtb and NR Mtb with MIC values of 12.5 mg/m L, which would lead to further optimization for more potent anti-TB candidates.展开更多
文摘A method of aerosol introduction for matrix-assisted laser desorption/ionization （MALDI） is described. The aerosol particles containing matrix and analyte enter directly into the aerosol time-of-flight mass spectrometer （ATOFMS） at atmospheric pressure. The scattered light signals from the aerosol particles are collected by a photomultiplier tube （PMT） and are passed on to an external electronic timing circuit, which determines particle size and is used to trigger a 266 nm pulsed Nd：YAG laser. The aerosol MALDI mass spectra and aerodynamic diameter of single particles can be obtained in real-time. Compared with other methods of liquid sample introduction, this method realizes detection of single particles and, more importantly, the sample consumption is lower. The effects of matrix-to-analyte ratio and laser pulse energy on analyte ion yield are examined. The optimal matrix-to-analyte ratio and laser energy are 50-110：1 and 200-400μl respectively.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61605218 and 61601442)the National Defense Science and Technology Innovation Foundation of the Chinese Academy of Sciences(Grant No.CXJJ-16S047)the National Major Scientific Instruments Development Project of China(Grant No.2013YQ030595)
文摘We demonstrate that, by undersampling scanning object with a reconstruction algorithm related to compressed sensing, an image with the resolution exceeding the finest resolution defined by the numerical aperture of the system can be obtained. Experimental results show that the measurements needed to achieve sub-Rayleigh resolution enhancement can be less than 10% of the pixels of the object. This method offers a general approach applicable to point-by-point illumination super-resolution techniques.
基金supported financially by the joint grant of the National Natural Science Foundation of China(NSFC)National Institute of Health(NIH)of USA(No.81161120402)the National 863 Program of China(No.2012AA020303)
文摘（~）-Calanolide A was the first natural product identified as an active agent against HIV-1 and Mycobacterium tuberculosis （Mtb）. In devising a scaffold-hopping strategy of structure modification of （＋）-calanolide A, we focused on the synthesis of calanolides by replacing ring D with various five or six membered nitrogen-containing heterocycles, hoping to get further understanding of the structure- activity relationship.
基金supported by Bill and Melinda Gates Foundation Grant (No. OPP1024029)supported financially by the National Natural Science Foundation of China (No. 91213303)
文摘We have explored the chemistry of N-oxide heterocycles and imidazoles replacing ring D of the natural product（＋）-calanolide A, and have synthesized 12 new analogues, two of which were active against both R Mtb and NR Mtb with MIC values of 12.5 mg/m L, which would lead to further optimization for more potent anti-TB candidates.
