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761.
Chia-Hsien Feng 《Analytica chimica acta》2009,649(2):230-86
Arecoline is the main alkaloid present in the areca nut (or betel nut) and it has central nervous system effects. Its pharmacological activities induce the constriction of the bronchial smooth muscles, and stimulation of the lacrimal and intestinal glands. Chewing areca nut is harmful to health because this habit may increase the risk of the development of oral cancer. In this study, a fast method was provided for the determination of areca alkaloids by matrix-assisted laser desorption ionization (MALDI) mass spectrometer with a time-of-flight (TOF) analyzer. Traditionally the MALDI-TOF method was not suitable for the analysis of small molecular weight (m/z < 600) compounds because of the high background of the matrix. In this study, a new matrix was utilized to decrease the background interference effectively. After simple sample preparation, 1 μL sample supernatant was mixed with 1 μL matrix and then deposited on the target plate. This new matrix was also used to test the MALDI imaging experiment. Application of this MALDI-TOF method for trace analysis of arecoline by this new matrix in human plasma at sub μM level proved workable. 相似文献
762.
Naoko Goto-Inoue Takahiro Hayasaka Takao Taki Tania Valdes Gonzalez Mitsutoshi Setou 《Journal of chromatography. A》2009,1216(42):7096-7101
Thin-layer chromatography (TLC) is a highly established convenient technique for lipid separation and partial characterization of neutral and acidic glycosphingolipids (GSLs) and phospholipids, in mixtures. Meanwhile, imaging mass spectrometry (IMS) is a promising tool for lipidomics. However, some lipid classes are detected more sensitively than others, which can lead to suppression effects when complex mixtures are analyzed. Therefore to analyze complex lipid mixtures, a precise separation into the individual lipid classes is necessary. Here we present our highly sensitive and convenient analytical technology that combines TLC and IMS, namely the TLC-Blot–MALDI-IMS method, to visualize whole lipids and individual molecular species with high sensitivity compared with common staining methods. This method allows for easy visualization of all lipids with a linear range of approximately one order of magnitude and precision <16% RSD, making it useful for differential display analysis of lipids. 相似文献
763.
Based on the reaction microscope at the institute of modern physics, the reaction mechanism in molecular ion-atom collisions is investigated experimentally. The features of this system is illustrated by a kinematically complete experhnent performed for the collision process. Using the so-called list-mode data recording technique and the coincidence measurement, the momentum vector of each fragment from the molecular ion were recorded event by event. The orientation of the molecular axis for H2^+ dissociation reactions could be determined for each event in the off-line analysis. The measured orientation of the molecular ion is believed the same as the one at the instance of collision under axial recoil approximation. The polar angle resolution of the molecular orientation of ±8° was obtained. 相似文献
764.
Katsunori Tanaka Kaori Minami Tsuyoshi Tahara Eric R. O. Siwu Koichi Koyama Satoshi Nozaki 《Journal of carbohydrate chemistry》2013,32(3):118-132
A Combined 6π-Azaelectrocyclization/Staudinger Approach to Protein and Cell Engineering: Noninvasive Tumor Targeting by N-Glycan-Engineered Lymphocytes
Published online:
02 June 2010 Graphical Abstract 相似文献
765.
In the last decade, droplet-based microfluidics has undergone rapid progress in the fields of single-cell analysis, digital PCR, protein crystallization and high throughput screening. It has been proved to be a promising platform for performing chemical and biological experiments with ultra-small volumes (picoliter to nanoliter) and ultra-high throughput. The ability to analyze the content in droplet qualitatively and quantitatively is playing an increasing role in the development and application of droplet-based microfluidic systems. In this review, we summarized the analytical detection techniques used in droplet systems and discussed the advantage and disadvantage of each technique through its application. The analytical techniques mentioned in this paper include bright-field microscopy, fluorescence microscopy, laser induced fluorescence, Raman spectroscopy, electrochemistry, capillary electrophoresis, mass spectrometry, nuclear magnetic resonance spectroscopy, absorption detection, chemiluminescence, and sample pretreatment techniques. The importance of analytical detection techniques in enabling new applications is highlighted. We also discuss the future development direction of analytical detection techniques for droplet-based microfluidic systems. 相似文献
766.
The present work examined the interactions of Activated Oxygen (AO) and Vacuum UV (VUV) radiation generated by oxygen RF plasma with Ultra-Strong Ultra High Molecular Weight Polyethylene (UHMWPE) fibres. The samples were exposed in the afterglow region, beyond the RF reactor exit. Surface morphology changes were characterized by Atomic Force Microscopy (AFM) in contact and tapping modes and Low-Vacuum (LV) and High-Resolution (HR) Scanning Electron Microscopy (SEM).Simultaneous exposure to AO and VUV caused surface erosion characterized by the formation of ordered domains and a morphological reconstruction into row structure. However, the different imaging techniques showed a variety of morphologies of the same surface depending on the imaging contrast mechanism. An explanation for the origin of these observed morphologies is presented. 相似文献
767.
Drug resistance, tumor heterogeneity, and poor selectivity make cancer treatment with current modalities a challenging and complicated task. Careful planning of diagnosis and therapy is required to build new strategies for treatment and management of cancer. The amalgamation of therapeutics and diagnostics in a single nano agent, known as theranostics is now possible due to the emergence of nanotechnology. Theranostics offers opportunities for personalized medicine by real-time monitoring of drug accumulation and dynamic modification of treatment depending on individual patient needs. Thus potential to reform disease management is held by theranostic nanoparticles. Amongst other nanosystems, inorganic nanoparticles have been widely used for developing theranostic drug delivery systems due to their favorable intrinsic properties. The last decade has seen a surge in development of such theranostic nanoparticles in which various inorganic materials in different combinations have been engineered to maximize the output with respect to specific applications. For example, Fe3O4@Au nanoparticles were developed for MRI, hyperthermia and magnetically controlled drug delivery. Several such combinations leading to innovative theranostic applications and their underlying mechanisms have been highlighted in this review. A review of patents and clinical trials of inorganic theranostic nanoparticles is also presented through which we understood that clinical translation still remains in the nascent stage. Thus, it is necessary to find and understand reasons for lack of clinical translations. Therefore, we have discussed the challenges associated with bench-to-bed translation of such inorganic nanoparticles which show immense potential in vitro but fail to deliver in long run. 相似文献
768.
Multi-domain High-Resolution Platform for Integrated Spectroscopy and Microscopy Characterizations 下载免费PDF全文
In recent decades, materials science has experienced rapid development and posed increasingly high requirements for the characterizations of structures, properties, and performances. Herein, we report on our recent establishment of a multi-domain (energy, space, time) high-resolution platform for integrated spectroscopy and microscopy characterizations, offering an unprecedented way to analyze materials in terms of spectral (energy) and spatial mapping as well as temporal evolution. We present several proof-of-principle results collected on this platform, including in-situ Raman imaging (high-resolution Raman, polarization Raman, low-wavenumber Raman), time-resolved photoluminescence imaging, and photoelectrical performance imaging. It can be envisioned that our newly established platform would be very powerful and effective in the multi-domain high-resolution characterizations of various materials of photoelectrochemical importance in the near future. 相似文献
769.
770.
Caixia Wang Yuxin Xie Xuefang Song Zhicong Chao Kun Wu Yanyun Fang Hongxia Zhao Prof. Huangxian Ju Prof. Ying Liu 《Angewandte Chemie (International ed. in English)》2023,62(50):e202312665
Aberrant expressions of biomolecules occur much earlier than tumor visualized size and morphology change, but their common measurement strategies such as biopsy suffer from invasive sampling process. In vivo imaging of slight biomolecule expression difference is urgently needed for early cancer detection. Fluorescence of rare earth nanoparticles (RENPs) in second near-infrared (NIR-II) region makes them appropriate tool for in vivo imaging. However, the incapacity to couple with signal amplification strategies, especially programmable signal amplification strategies, limited their application in lowly expressed biomarkers imaging. Here we develop a 980/808 nm NIR programmed in vivo microRNAs (miRNAs) magnifier by conjugating activatable DNAzyme walker set to RENPs, which achieves more effective NIR-II imaging of early stage tumor than size monitoring imaging technique. Dye FD1080 (FD1080) modified substrate DNA quenches NIR-II downconversion emission of RENPs under 808 nm excitation. The miRNA recognition region in DNAzyme walker is sealed by a photo-cleavable strand to avoid “false positive” signal in systemic circulation. Upconversion emission of RENPs under 980 nm irradiation activates DNAzyme walker for miRNA recognition and amplifies NIR-II fluorescence recovery of RENPs via DNAzyme catalytic reaction to achieve in vivo miRNA imaging. This strategy demonstrates good application potential in the field of early cancer detection. 相似文献