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Systematic Truncating Aptamers to Create High Performance Graphene Oxide (GO)-based Aptasensors for Multiplex Detection of Mycotoxins
摘要： Graphene Oxide (GO)-based aptasensor is currently one of the most popular sensing platforms for simple and rapid detection of various targets. Unfortunately, the GO-based aptasensors with long aptamer strands typically show unsatisfactory performance resulted from insignificant structural transformations upon target bindings. We report herein the utilization of an aptamer truncating strategy to combat such a challenge. Taking a pre-selected anti-aflatoxin B1 (AFB1) aptamer (P-AFB1-50) as a trial system, we sequentially remove the extraneous nucleotides within the aptamer by means of circular dichroism (CD) spectroscopy and binding affinity analysis. Particularly, the ratio of the quenching constants between the GO sheets and the truncated aptamers (labelled with fluorophores) in the absence and presence of target was determined for each of the truncated aptamers to evaluate the optimal sequence. As a result, the truncated aptamer comprising 40 nucleotides was confirmed to show the highest FL output and best detection limit upon conjugation with GO sheets. More importantly, we demonstrated that this truncating strategy is versatile, i.e., it can be easily extended to other aptamer systems (anti-ochratoxin A (OTA) aptamer, P-OTA-61, as an example) for extraneous nucleotide identification. Impressively, the two optimal truncated aptamers can work together on GO sheets to achieve a simultaneous detection of two different mycotoxins (i.e., AFB1 and OTA) in one single testing. Essentially, this research opens a new avenue for the design and testing of aptamer/GO based-sensing platforms for rapid, low-cost and multiplex quantification of analytical targets of interest.
关键词： DNA/GO-based biosensors,AFB1,OTA,long-chain aptamer,multiplex detection,extraneous nucleotide truncation
更新于2025-11-14 15:28:36
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Multi‐Resonance Induced Thermally Activated Delayed Fluorophores for Narrowband Green OLEDs
摘要： With the increment of data scale, distributed machine learning has received more and more attention. However, as the data grows, the dimension of the dataset will increase rapidly, which leads to the increment of the communication traffic in the distributed computing cluster and decreases the performance of the distributed algorithms. This paper proposes a message filtering strategy based on asynchronous alternating direction method of multipliers (ADMM), which can effectively reduce the communication time of the algorithm while ensuring the convergence of the algorithm. In this paper, a soft threshold filtering strategy based on L1 regularization is proposed to filter the parameter of master node, and a gradient truncation filtering strategy is proposed to filter the parameter of slave node. Besides, we update the algorithm asynchronously to reduce the waiting time of the master node. Experiments on large-scale sparse data show that our algorithm can effectively reduce the traffic of messages and make the algorithm reach convergence in a shorter time.
关键词： gradient truncation,distributed machine learning,message filtering,asynchronous update,ADMM,L1 regularization
更新于2025-09-19 17:13:59
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MALDI Imaging Mass Spectrometry Spatially Maps Age-Related Deamidation and Truncation of Human Lens Aquaporin-0
摘要： PURPOSE. To spatially map human lens Aquaporin-0 (AQP0) protein modifications, including lipidation, truncation, and deamidation, from birth through middle age using matrix-assisted laser desorption ionization (MALDI) imaging mass spectrometry (IMS). METHODS. Human lens sections were water-washed to facilitate detection of membrane protein AQP0. We acquired MALDI images from eight human lenses ranging in age from 2 months to 63 years. In situ tryptic digestion was used to generate peptides of AQP0 and peptide images were acquired on a 15T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. Peptide extracts were analyzed by liquid chromatography–tandem mass spectrometry (LC-MS/MS) and database searched to identify peptides observed in MALDI imaging experiments. RESULTS. Unmodified, truncated, and fatty acid–acylated forms of AQP0 were detected in protein imaging experiments. Full-length AQP0 was fatty acid acylated in the core and cortex of young (2- and 4-month) lenses. Acylated and unmodified AQP0 were C-terminally truncated in older lens cores. Deamidated tryptic peptides (t0.9847 Da) were mass resolved from unmodified peptides by FTICR MS. Peptide images revealed differential localization of un-, singly-, and doubly-deamidated AQP0 C-terminal peptide (239–263). Deamidation was present at 4 months and increases with age. Liquid chromatography–MS/MS results indicated N246 undergoes deamidation more rapidly than N259. CONCLUSIONS. Results indicated AQP0 fatty acid acylation and deamidation occur during early development. Progressive age-related AQP0 processing, including deamidation and truncation, was mapped in human lenses as a function of age. The localization of these modified AQP0 forms suggests where AQP0 functions may change throughout lens development and aging.
关键词： deamidation,truncation,aging,MALDI IMS,in situ digestion,posttranslational modifications,ocular lens
更新于2025-09-11 14:15:04
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X-ray structural analysis of an epitaxially grown Ag film/Si(111)$\sqrt{3} \times \sqrt{3} $-B substrate interface
摘要： We investigated the structure of the Si(111)√3×√3-B surface and epitaxially grown Ag(111) film/Si(111)√3×√3-B substrate interface using surface X-ray diffraction. An analysis of their crystal truncation rod and fractional order rod scatterings revealed a good agreement between the structure of the Si(111)√3×√3-B surface and previous theoretical studies when taking into account structural inhomogeneity caused by subsurface defects. At the Ag film/Si(111)√3×√3-B substrate interface, the Si(111)√3×√3-B surface reconstruction was maintained intact. The experimentally determined positions of Ag atoms were displaced from the ideal Ag(111) bulk sites, and a 3×3 periodicity was introduced to the bottom layer of the Ag film at the interface. The 3×3 periodic corrugation was transferred, albeit damped, to the upper layer. This transfer was considered to be the origin of the 3×3 periodic pattern at the Ag film surface on the Si(111)√3×√3-B substrate, a pattern observed in our previous scanning tunneling microscope study.
关键词： crystal truncation rod,3×3 periodicity,surface X-ray diffraction,Si(111)√3×√3-B substrate,epitaxial growth,Ag film,fractional order rod,X-ray structural analysis
更新于2025-09-09 09:28:46
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A Near-Field to Far-Field RCS Measurement Method for Multiple-Scattering Target
摘要： It is challenging to perform the near-field to far-field transformation with a high precision for the multiple-scattering targets using the conventional monostatic radar cross section (RCS) measurement. In this paper, a novel near-field to far-field transformation method with bistatic RCS measurement is proposed. First, the RCS measurement is perceived as a double radiation model. Doing this, the relationship of near-field data and far-field data at different angles is derived, and the convolution function is given under the cylindrical wave. Second, the near-field scattering data are acquired using the proposed bistatic RCS measurement method that combines one transmission and multiple receptions with the rotation of a revolving table. The near-field data are then extrapolated twice with the convolution function, and the far-field RCS are obtained accordingly. Moreover, this paper also analyzes the truncation angular and sampling intervals for the measurement consideration. Finally, the effectiveness and the high precision of the proposed transformation approach for the multiple-scattering target are demonstrated using the numerical simulations and the experimental characterization with an example of dihedral structures.
关键词： near-field to far-field transformation,multiple-scattering target,sampling interval,Bistatic radar cross section (RCS) measurement,truncation angular
更新于2025-09-04 15:30:14