- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Fluorogenic “photoclick” labelling of DNA using a Cy3 dye
摘要： Two 2’-deoxyuridines as new building blocks for automated DNA synthesis carry a small aryltetrazole as “photoclickable” group at their 5-positions. The postsynthetic “photoclick” labeling of such presynthesized DNA using a maleimide-modified Cy3 dye shows an up to 17-fold fluorogenicity due to an energy transfer between the pyrazoline moiety and the Cy3 fluorophore in the DNA products. This concept is also applicable to other maleimide-modified dyes.
关键词： Fluorogenic labeling,DNA,tetrazole,photoclick reaction,energy transfer,Cy3 dye
更新于2025-09-19 17:15:36
-
Fluorine-18 click radiosynthesis and MicroPET/CT evaluation of a small peptide-a potential PET probe for carbonic anhydrase IX
摘要： Carbonic anhydrase IX (CA IX) is the first carbonic anhydrase found to be associated with cancer that is over-expressed in a variety of human solid tumors. As a surrogate marker for hypoxia, the expression of CA IX is strongly upregulated in hypoxic tumors by hypoxia and hypoxia-inducible factor 1a (HIF-1a). In our pursuit of a CA IX-specific PET probe, we designed and synthesized a peptide-based CA IX imaging probe by the efficient click reaction of 1,3-dipolar cycloaddition of terminal alkynes and organic azides. The probe 18F-CA IX-P1-4-10 was obtained with a radiochemical yield of 35-45% (n = 5) and radiochemical purity of >99% in 70-80 min (HPLC purification time included). 18F-CAIX-P1-4-10 had good stability in phosphate buffered saline (PBS), but about 51% peptide degradation was detected in new-born calf serum (NBCS) after incubation. Preliminary microPET/CT experiments demonstrated a specific uptake of 18F-CA IX-P1-4-10 in HT29 tumor and the uptake of 18F-CA IX-P1-4-10 was blocked by peptide CA IX-P1-4-10-Yne pretreatment. Immunohistochemical staining and western blotting studies confirmed the HT29 tumor was CA IX-positive which further proved tumor accumulation of 18F-CA IX-P1-4-10 was correlated with CA IX expression. The results suggest that 18F-CA IX-P1-4-10 is a promising PET tracer for the specific imaging of CA IX-expressing tumors at the molecular level.
关键词： peptide,tumor hypoxia,18F-labeling,Carbonic anhydrase IX,PET imaging
更新于2025-09-19 17:15:36
-
Synthesis and Preliminary Evaluations of a Triazole-cored Antagonist ([18F]N2B-0518) as PET Imaging Probe for GluN2B Subunit in the Brain
摘要： GluN2B is the most studied subunit of N-methyl-D-aspartate receptors (NMDARs) and implicated in the pathologies of various central nervous system disorders and neurodegenerative diseases. As pan NMDAR antagonists often produce debilitating side effects, new approaches in drug discovery have shifted to subtype-selective NMDAR modulators, especially GluN2B-selective antagonists. While positron emission tomography (PET) studies of GluN2B-selective NMDARs in the living brain would enable target engagement in drug development and improve our understanding in the NMDAR signaling pathways between normal and disease conditions, a suitable PET ligand is yet to be identified. Herein we developed an 18F-labeled potent antagonist, 2-((1-(4-[18F]fluoro-3-methylphenyl)-1H-1,2,3-triazol-4-yl)methoxy)-5-methoxypyrimidine ([18F]13; also called [18F]N2B-0518) as a PET tracer for imaging the GluN2B subunit. The radiofluorination of [18F]13 was efficiently achieved by our spirocyclic iodonium ylide (SCIDY) method. In in vitro autoradiography studies, [18F]13 displayed highly region-specific binding in brain sections of rat and non-human primate, which was in accordance with the expression of GluN2B subunit. Ex vivo biodistribution in mice revealed that [18F]13 could penetrate the blood-brain barrier with moderate brain uptake (3.60% ID/g at 2 min) and rapid washout. Altogether, this work provides a GluN2B-selective PET tracer bearing new chemical scaffold and shows high specificity to GluN2B subunit in vitro, which may pave the way for the development of a new generation of GluN2B PET ligands.
关键词： subtype-selective,PET imaging,18F-labeling,autoradiography,GluN2B subunit,spirocyclic iodonium ylide
更新于2025-09-19 17:15:36
-
Deep Learning Applications on Multitemporal SAR (Sentinel-1) Image Classification Using Confined Labeled Data: The Case of Detecting Rice Paddy in South Korea
摘要： The applicability of deep learning to remote sensing is rapidly increasing in accordance with the improvement in spatiotemporal resolution of satellite images. However, unlike satellite images acquired in near-real-time over wide areas, there are limited amount of labeled data used for model training. In this article, three kinds of deep learning applications—data augmentation, semisupervised classification, and domain-adapted architecture—were tested in an effort to overcome the limitation of insufficient labeled data. Among the diverse tasks that can be used for classification, rice paddy detection in South Korea was performed for its ability to fully utilize the advantages of deep learning and high spatiotemporal image resolution. In the process of designing each application, the domain knowledge of remote sensing and rice phenology was integrated. Then, all possible combinations of the three applications were examined and evaluated with pixel-based comparisons in various environments and city-level comparisons using national statistics. The results of this article indicated that all combinations of the applications can contribute to increase classification performance, even though the uncertainty involved in imitating or utilizing unlabeled data remains. As the effectiveness of the proposed applications was experimentally confirmed, enhancement in the applicability of deep learning was expected in various remote sensing areas. In particular, the proposed applications would be significant when they are applied to a wide range of study areas and high-resolution images, as they tend to require a large amount of learning data from diverse environments, owing to high intraclass heterogeneity.
关键词： remote sensing,semisupervised classification,data labeling,deep learning,Data augmentation,domain adaptation
更新于2025-09-19 17:13:59
-
Optical properties of soil DOM are related to acidic functions of its components as revealed by fractionation, selective deuteromethylation and ultra-high resolution mass spectrometry
摘要： The goal of this study was to establish relationship between the optical properties of soil dissolved organic matter (DOM) and acidic functions carried by its individual constituents. We obtained twelve fractions of DOM samples using sequential solid phase extraction on nonionic sorbent at steadily lowered pH values: 7, 5, 3, 2, which correspond to low bounds of pKa values of phenols, aliphatic and aromatic carboxylic acids and ketoacids. The structural studies were conducted with a use of NMR and selective deuteromethylation of isolated fractions coupled to ultra-high resolution mass spectrometry. First, a gradual shift of molecular compositions was observed from reduced components to aromatic oxidized compounds isolated at pH7 and 2, respectively. Changes in molecular compositions were accompanied by a red shift of fluorescence spectra. Further application of deuteromethylation enabled to distinguish DOM constituents with different amount of carboxylic groups. Moreover, identification of structural isomers in a single DOM sample was achieved. Statistical analysis revealed that red shift of fluorescence is facilitated by the increase of a contribution of aromatic polycarboxylic acids with high conjugation lengths. Additionally, analysis of the labeled fractionated permafrost thaw DOM directly showed carboxyl-rich alicyclic molecules, while same components from lower-latitude DOM were assigned to lignin-like species.
关键词： DOM,structure,separation,acidity,fluorescence,SPE extraction,isotopic labeling,FTICR MS
更新于2025-09-19 17:13:59
-
[IEEE 2019 International Conference on Electrical, Electronics and Computer Engineering (UPCON) - ALIGARH, India (2019.11.8-2019.11.10)] 2019 International Conference on Electrical, Electronics and Computer Engineering (UPCON) - Comparative Study of MPPT Techniques for Solar Photovoltaic System
摘要： Raman spectroscopy performed using optical fibers, with excitation at 1064 nm and a dispersive detection scheme, was utilized to measure a selection of unifloral honeys produced in the Italian region of Calabria. The honey samples had three different botanical origins: chestnut, citrus, and acacia. A multivariate processing of the spectroscopic data enabled us to distinguish their botanical origin, and to build predictive models for quantifying important nutraceutic indicators, such as the main sugars and potassium. Furthermore, the Raman spectra of chestnut honeys were compared with the taste profile measured by an electronic tongue: A good correlation to a bitter-savory taste was obtained. This experiment indicates the excellent potential of Raman spectroscopy as a modern analytical tool for the nondestructive and rapid multi-component analysis of food quality indicators.
关键词： Food products,sugar,predictive models,labeling,pattern analysis,Raman scattering
更新于2025-09-19 17:13:59
-
Sparsely Excited Tightly Coupled Dipole Arrays Based on Irregular Array Techniques
摘要： We propose a method for adapting Semantic Role Labeling (SRL) systems from a source domain to a target domain by combining a neural language model and linguistic resources to generate additional training examples. We primarily aim to improve the results of Location, Time, Manner and Direction roles. In our methodology, main words of selected predicates and arguments in the source-domain training data are replaced with words from the target domain. The replacement words are generated by a language model and then filtered by several linguistic filters (including Part-Of-Speech (POS), WordNet and Predicate constraints). In experiments on the out-of-domain CoNLL 2009 data, with the Recurrent Neural Network Language Model (RNNLM) and a well-known semantic parser from Lund University, we show enhanced recall and F1 without penalizing precision on the four targeted roles. These results improve the results of the same SRL system without using the language model and the linguistic resources, and are better than the results of the same SRL system that is trained with examples that are enriched with word embeddings. We also demonstrate the importance of using a language model and the vocabulary of the target domain when generating new training examples.
关键词： linguistic resources,open domain,Language model,semantic role labeling
更新于2025-09-19 17:13:59
-
Fluorometric visualization of mucin 1 glycans on cell surfaces based on rolling-mediated cascade amplification and CdTe quantum dots
摘要： A rolling-mediated cascade (RMC) amplification strategy is described for improved visualization of profiling glycans of mucin 1 (MUC 1) on cell surfaces. CdTe quantum dots (QDs) are used as fluorescent labels. The RMC based amplification allows even distinct glycoforms of MUC1 to be visualized on the surface of MCF-7 cell via an amplified F?rster resonance energy transfer (FRET) imaging strategy that works at excitation/emission wavelengths of 345/610 nm. This is achieved by utilizing antibody against MUC1 modified with the fluorescent label 7-amino-4-methylcoumarin-3-acetic acid (AMCA) as the energy donor in FRET. The QDs (used to label surface glycans) act as acceptors. N-Azidoacetylgalactosamine-Acetylated (Ac4GalNAz) as a non-natural azido sugar, can be incorporated into the glycans of the cell surface, which can promote further labeling. The method has the advantage of only requiring a small amount of non-natural sugar to be introduced in metabolic glycan labeling since too much of an artificial sugar will interfere with the physiological functions of cells.
关键词： Cancer marker,Azide polysaccharide,FRET,Glycosylation,Glycoprotein,DNA probe,Quantum dots,Click reaction,Metabolic labeling,Rolling-mediated cascade amplification
更新于2025-09-19 17:13:59
-
Systematic investigation of bioorthogonal cellular DNA metabolic labeling in a photo-controlled manner
摘要： Two 5-ethynyl-2′-deoxyuridine (EdU) derivatives photocaged on N-3 or 3′ position were synthesized by simple and effective methods, through direct UV irradiation on cells treated with them, cellular DNA metabolic labeling was successfully controlled. The systematic investigation of optical-cleavage position and type in living systems contributes to form a more integrated repertoire of bioorthogonal cleavage reaction.
关键词： DNA metabolic labeling,Cell imaging,Photocage group,Modified nucleoside,Bioorthogonal chemistry
更新于2025-09-19 17:13:59
-
Biocompatible quantum dot-antibody conjugate for cell imaging, targeting and fluorometric immunoassay: crosslinking, characterization and applications
摘要： Quantum dots (QDs) are important fluorescent probes that offer great promise for bio-imaging research due to their superior optical properties. However, QDs for live cell imaging and the tracking of cells need improving labeling efficiency, and reducing more investigation to simplify processing procedures, chronic toxicity. In this study, QDs were functionalized with bovine serum albumin (BSA) via a chemical linker. Anti-human immunoglobulin antibodies were oxidized by sodium periodate to create reactive aldehyde groups for a spontaneous reaction with the amine groups of BSA-modified QDs. An antibody-labeled QD bioconjugate was characterized using agarose gel electrophoresis, dynamic light scattering, and zeta potential. Using fluorescence spectroscopy, we found that the fluorescence of QDs was retained after multiple conjugation steps. The cell-labeling function of the QD bioconjugate was confirmed using an image analyzer and confocal microscopy. The QD bioconjugate specifically targeted the human immunoglobulin on the membrane surface of recombinant cells. The QD bioconjugate applied in fluorometric immunoassay was effective for the quantitative analysis of human immunoglobulin in an enzyme-linked immunosorbent assay. The developed QD bioconjugate may offer a promising platform to develop biocompatible tools to label cells and quantify antibodies in the immunoassay.
关键词： Quantum dots,Bio-imaging,Fluorescent probes,Cell labeling,Fluorometric immunoassay
更新于2025-09-16 10:30:52