Eliminate Background Interference Research Articles

Harnessing long-lived visible phosphorescence to eliminate background interference from fingermark images

Minimising background fluorescence can enhance the visible details of treated fingerprints. Here, a 4-tpt fingerprint powder exhibiting long-lived phosphorescence is applied to this end. The powder was found to suppress background fluorescence, including on challenging surfaces, when using standard forensic equipment and eschewing specialized or bespoke imaging techniques.

Human Action Recognition Based on Motion Feature and Manifold Learning

Human action recognition is an important task in the fields of video content analysis and computer vision. Since the performance of most existing action recognition frameworks depends on the representation of features, many researches aim to construct more discriminative features. In this paper, we propose a manifold learning framework based on optical flow for action recognition. First, we calculate the dense optical flow field of the original video sequence, and the attention pooling layer (AP) is adopted to separate target area and background area to eliminate background interference. On this basis, motion features (MF) based on the physical characteristics of dense optical flow are developed to characterize human motion information. After that, manifold learning is introduced to calculate the motion variance features (MVF), which reflect the change rate of motion features and measure the spatial correlation between features in non-Euclidean space. Finally, fusing the MVF obtained by manifold learning and MF, feeding fusion features into two fully connected layers (FC) in series for action classification and recognition. Experiments on several classic datasets show that the proposed method achieves 0.98%, 1.86% and 0.99% performance improvement on UCF 101, HMDB51 and JHMDB.

Enhanced performance of an electrochemical aptasensor for real-time detection of vascular endothelial growth factor (VEGF) by nanofabrication and ratiometric measurement

Achieving a biosensing interface without baseline drift caused by variables in matrix samples is essential for real-time detection of analytes. In this study, we developed a molecular beacon based electrochemical aptasensor to realize the ratiometric signal quantification of VEGF in serum by surface modification of nanocomposites of graphene oxide/methylene blue (GO/MB) and AuNPs followed by the attachment of ferrocene-labeled aptamer (aptamer-Fc) against VEGF. The presence of VEGF can trigger the configuration change of aptamer-Fc, resulting in the redox probe Fc being far away from the electrode surface to attenuate the electrochemical communication between electrode and Fc. Meanwhile, signal of MB also decreased due to the impediment of aptamer-Fc to electron transfer passage. The achieved GC-rGO/MB-AuNPs-aptamer-Fc sensing interface was successfully used for the sensitive detection of VEGF in real-time with a linear detection range 2–500 pg mL−1 and detection limit of 0.1 pg mL−1 based on ratiometric dual signal (Fc and MB) read-out. It was observed loading MB and AuNPs to the GO based sensing interface was favorable to enhance the analytical performance in terms of sensitivity and capability to effectively eliminate background interference. This electrochemical aptasensor provides a universal and reliable biosensing platform which is potential for real-time and sensitive tracking of various cytokines in vivo.

Pedestrian Detection at Night in Infrared Images Using an Attention-Guided Encoder-Decoder Convolutional Neural Network

Pedestrian-related accidents are much more likely to occur during nighttime when visible (VI) cameras are much less effective. Unlike VI cameras, infrared (IR) cameras can work in total darkness. However, IR images have several drawbacks, such as low-resolution, noise, and thermal energy characteristics that can differ depending on the weather. To overcome these drawbacks, we propose an IR camera system to identify pedestrians at night that uses a novel attention-guided encoder-decoder convolutional neural network (AED-CNN). In AED-CNN, encoder-decoder modules are introduced to generate multi-scale features, in which new skip connection blocks are incorporated into the decoder to combine the feature maps from the encoder and decoder module. This new architecture increases context information which is helpful for extracting discriminative features from low-resolution and noisy IR images. Furthermore, we propose an attention module to re-weight the multi-scale features generated by the encoder-decoder module. The attention mechanism effectively highlights pedestrians while eliminating background interference, which helps to detect pedestrians under various weather conditions. Empirical experiments on two challenging datasets fully demonstrate that our method shows superior performance. Our approach significantly improves the precision of the state-of-the-art method by 5.1% and 23.78% on the Keimyung University (KMU) and Computer Vision Center (CVC)-09 pedestrian dataset, respectively.

Salient object detection of dairy goats in farm image based on background and foreground priors

In order to achieve object detection of dairy goats in farm image efficiently and accurately, this paper proposes a novel salient object detection approach based on background and foreground priors. First, we improve the FastMBD algorithm to generate background-prior-based saliency map, which eliminate background interference initially. Second, the approach of seed selection is optimized to determine the foreground seeds more accurately, and then saliency map is generated based on manifold ranking to further eliminate the background interference. Finally, two saliency maps are fused, and then combined with post-processing to achieve saliency object detection of farm image. Subsequently, we also use the threshold segmentation based on K-Means algorithm to separate the objects and background. Moreover, the horizontal scanning method and contour extraction are employed to realize the extraction and counting of dairy goats. Experimental results show that the proposed approach based on background and foreground priors has promising performance, and the accuracy of the proposed segmentation method was up to 89.503%.

Enrichment of the fetal fraction in non-invasive prenatal screening reduces maternal background interference

Measurement of cell-free fetal DNA (cffDNA) is an indispensable process for non-invasive prenatal screening (NIPS). According to recent studies, cffDNA in maternal plasma can be enriched for various lengths of fragments, and a sufficient amount of cffDNA can effectively eliminate background interference on the part of maternal DNA. Therefore, we developed a simple and effective separation method, improved NIPS (iNIPS), that enriches the fetal fraction and improves the accuracy of NIPS for fetal aneuploid detection. We adopted a novel strategy to achieve enrichment of 125–135 bp cell-free DNA (cfDNA) by e-gel electrophoresis. To evaluate clinical performance, we compared NIPS and iNIPS results from 2153 retrospective clinical samples. Of the 22 samples with NIPS results of “no call”, 17 samples were reclassified as “unaffected” (9 cases of chr13, 5 cases of chr18, and 3 cases of chr21); 2 samples remained classified as “no call” (1 case of chr18 and 1 case of chr21); and 3 samples were identified as T21 by iNIPS. The average increase in abundance of cfDNA fragments of 125–135 bp was 2.5 times, and the average decrease in maternal background interference was 1.3 times. On this basis, the detection of fetal aneuploidy was highly improved with the fetal fraction as low as 2%; iNIPS achieved 100% sensitivity and 99.90% specificity in retrospective samples.

Ratiometric fluorescence nanosensors based on core-shell structured carbon/CdTe quantum dots and surface molecularly imprinted polymers for the detection of sulfadiazine.

Sulfadiazine is an environmental pollutant derived from abuse of antibiotics. Its content in environmental water is closely related to human health. Thus, a novel dual-emission surface molecularly imprinted nanosensor is designed for the specific adsorption and detection of sulfadiazine. In the system, blue emissive carbon quantum dots wrapped with silica served as the internal reference signal for eliminating background interference, while red emissive thioglycolic acid modified CdTe quantum dots (CdTe QDs), which are low dimensional semiconductor materials by the combination of cadmium and tellurium with excellent optical properties, were encapsulated in the imprinted layer to offer recognition signal. The fluorescence of CdTe quantum dots was quenched and the fluorescence quenching degree of carbon quantum dots was inconspicuous with the increase of concentration of sulfadiazine, thereby reflecting the color change. The detection of sulfadiazine was successfully achieved in a concentration range of 0.25-20μmol/L with detection limit of 0.042μmol/L and nanosensors had specific recognition for sulfadiazine over its analogues. Compared to single-emission fluorescence sensors, ratiometric fluorescence nanosensors had wider linear range and higher detection accuracy. Furthermore, the nanosensors were also successfully applied for the determination of sulfadiazine in real water and milk samples with acceptable recoveries. The study provides a feasible method for the detection of sulfadiazine and a reference for the detection of sulfonamides.

Recent progress in background-free latent fingerprint imaging

Owing to their unique pattern and abundant chemical composition, latent fingerprints (LFPs) can serve as “ID cards” and “information banks” of donors and therefore are valuable for forensic investigation, access control, and even medical diagnosis. LFP imaging has attracted considerable attention, and a great variety of contrast agents has been developed. In LFP imaging, background signals such as background fluorescence from the underlying surface can seriously blur the LFP images and decrease imaging sensitivity; thus, great efforts have been made to eliminate background interference. Here, we stratify the recent progress in background-free LFP imaging by making use of the difference in properties between contrast agents and background compounds. For example, near-infrared (NIR) light-activatable contrast agents can efficiently remove background signals in LFP imaging because the background compounds cannot be excited by NIR light, showing that the difference in excitation properties between contrast agents and background compounds can be employed to eliminate background interference. This review is organized around background-free LFP imaging based on the difference in optical properties between contrast agents and background compounds: (i) different excitation wavelengths, (ii) different emission wavelengths, (iii) different luminescence lifetime values, (iv) different plasmonic properties, (v) different photothermal properties, and (vi) different electrochemiluminescence properties.

Precast Gelatin-Based Molds for Tissue Embedding Compatible with Mass Spectrometry Imaging.

Preparation of tissue for matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) generally involves embedding the tissue followed by freezing and cryosectioning, usually between 5 and 25 μm thick, depending on the tissue type and the analyte(s) of interest. The brain is approximately 60% fat; it therefore lacks rigidity and poses structural preservation challenges during sample preparation. Histological sample preparation procedures are generally transferable to MALDI-MSI; however, there are various limitations. Optimal cutting temperature compound (OCT) is commonly used to embed and mount fixed tissue onto the chuck inside the cryostat during cryosectioning. However, OCT contains potential interferences that are detrimental to MALDI-MSI, while fixation is undesirable for the analysis of some analytes either due to extraction or chemical modification (i.e., polar metabolites). Therefore, a method for both fixed and fresh tissue compatible with MALDI-MSI and histology is desirable to increase the breadth of analyte(s), maintain the topographies of the brain, and provide rigidity to the fragile tissue while eliminating background interference. The method we introduce uses precast gelatin-based molds in which a whole mouse brain is embedded, flash frozen, and cryosectioned in preparation for mass spectrometry imaging (MSI).

Region-of-interest extraction based on spectrum saliency analysis and coherence-enhancing diffusion model in remote sensing images

Saliency analysis, which is a fast and efficient method for extracting Regions of Interest (ROIs), has been applied in the field of remote sensing image analysis. In this paper, a novel saliency analysis model is proposed using spectrum saliency analysis (SSA) and coherence-enhancing diffusion model (CED). In SSA, the probability of each pixel intensity value is counted to get the one-dimensional histogram for each band, then information content of each band is calculated according to the one-dimensional histogram and generate spectrum saliency map after the information content weighted fusion of each band. In CED, coherence-enhancing diffusion model is introduced for spectrum saliency map that aims to smooth internal ROIs and eliminate background interference to improve the precision, accuracy and completeness of the resulting saliency map. Finally, ROIs are segmented from the saliency maps of original images by an adaptive threshold segmentation algorithm. Several experiments were conducted to evaluate the overall performance of the proposed model compared with the other eight outstanding models qualitatively and quantitatively. The experimental evaluations show that the proposed model outperforms the relevant outstanding models.

Stepwise multiphoton activation fluorescence reveals a new method of melanin detection

The stepwise multiphoton activated fluorescence (SMPAF) of melanin, activated by a continuous-wave mode near infrared (NIR) laser, reveals a broad spectrum extending from the visible spectra to the NIR and has potential application for a low-cost, reliable method of detecting melanin. SMPAF images of melanin in mouse hair and skin are compared with conventional multiphoton fluorescence microscopy and confocal reflectance microscopy (CRM). By combining CRM with SMPAF, we can locate melanin reliably. However, we have the added benefit of eliminating background interference from other components inside mouse hair and skin. The melanin SMPAF signal from the mouse hair is a mixture of a two-photon process and a third-order process. The melanin SMPAF emission spectrum is activated by a 1505.9-nm laser light, and the resulting spectrum has a peak at 960 nm. The discovery of the emission peak may lead to a more energy-efficient method of background-free melanin detection with less photo-bleaching.

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Many sensitized transplant patients have HLA-specific antibodies due to previous graft failures, blood transfusions, and pregnancies. These humoral responses are typically polyclonal in nature, antibody composition is distinct to each individual, and it is difficult to precisely determine antibody specificity. Distinct antibodies cannot be readily isolated for individual characterization. In this study we isolate distinct anti-HLA antibodies to evaluate their phenotypic and functional traits. After characterizing sera from highly sensitized patients with a single antigen assay, sera were passed over HLA-specific separation devices made by coupling purified soluble HLA to a sepharose matrix. A scheme of multiple separation rounds involving loading and elution cycles with different HLA allele combinations was applied. This process resulted in mono-specific patterns of HLA reactivity measured by a Luminex-based bead assay. Our results show that complex patterns of sera reactivity can be reduced to more simplified outputs allowing better interpretation of individual antibody populations. Separation of IgG, IgA, and IgM further assisted in the interpretation of these responses. Furthermore, this technique was also of use in evaluating false positive/negative assay signals, strengthening otherwise weak antibody reactivity, and eliminating background interference. Antibody concentration, isotype, epitope specificity, cross-reactivity, and the ability to fix complement have all been implicated as factors that contribute to the pathogenicity of anti-HLA antibodies following organ transplantation. The deconvolution of antibody reactivity patterns can assist in the assessment of risk factors for immunologic rejection as well as provide new insights into anti-HLA antibody profiling and epitope structure analysis.

2325 AUTOANTIBODY SIGNATURES AS BIOMARKERS TO DISTINGUISH PROSTATE CANCER FROM BENIGN PROSTATIC HYPERPLASIA USING A NATIVE ANTIGEN CAPTURE MICROARRAY PLATFORM

You have accessJournal of UrologyProstate Cancer: Markers1 Apr 20112325 AUTOANTIBODY SIGNATURES AS BIOMARKERS TO DISTINGUISH PROSTATE CANCER FROM BENIGN PROSTATIC HYPERPLASIA USING A NATIVE ANTIGEN CAPTURE MICROARRAY PLATFORM Dennis O'Rourke, Daniel DiJohnson, Michael O'Leary, Jerome Richie, and Brian Liu Dennis O'RourkeDennis O'Rourke Boston, MA More articles by this author , Daniel DiJohnsonDaniel DiJohnson Boston, MA More articles by this author , Michael O'LearyMichael O'Leary Boston, MA More articles by this author , Jerome RichieJerome Richie Boston, MA More articles by this author , and Brian LiuBrian Liu Boston, MA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.2572AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Serum prostate specific antigen (PSA) levels lack the specificity to differentiate prostate cancer from benign prostate hyperplasia (BPH), resulting in unnecessary biopsies. We now report the identification of 5 autoantibody signatures to specific cancer targets which may be capable of ruling out a diagnosis of cancer for patients with non-malignant prostatic disease, such as BPH, in patients with elevated serum PSA. METHODS To discover new biomarkers which may distinguish between prostate cancer and BPH, a native antigen capture microarray platform was used. Briefly, well-characterized monoclonal antibodies were arrayed onto nano-particle slides to capture native antigens from prostate cancer cells. Using the immobilized antigens as baits, autoantibodies from prostate cancer patients and patients with BPH can be isolated and probed. From preliminary experiments using an initial set of over 500 cancer related antigens, a customized array containing 27 unique antigens was further tested. Prostate cancer patient (n=41) and BPH patient serum samples with a mean follow-up of 6.8 years without the diagnosis of cancer (n=39) were obtained. 100ug of IgGs were purified and dye labeled with a Cy3 dye and incubated on the arrays. The arrays were scanned for fluorescence and the intensity was quantified. For each spot, a signal-to-noise ratio (SNR) was measured to eliminate background interference. Through comparative analysis of the prostate cancer arrays and the BPH arrays, autoantibody signatures were identified. Receiver operating characteristic curves were produced and the area under the curve (AUC) was determined for the 27 antigens. RESULTS Using the native antigen capture microarray platform, we found unique autoantibody signatures capable of distinguishing between prostate cancer and BPH. A SNR was calculated for each autoantibody reactivity on each array and compared. The top 5 autoantibody signatures were found to react with TARDBP, TLN1, PARK7, PSIP1, and CALD1. Combining these antigens resulted in an AUC of 0.95 compared to 0.50 for PSA when differentiating between prostate cancer and BPH in our cohort. In addition, the coefficient of variance between duplicate runs for a given sample averaged 14.8% (range 11%–22%). CONCLUSIONS Our results demonstrate the ability of a native antigen capture microarray platform to identify specific autoantibody signatures that can differentiate prostate cancer from BPH, and may result in the reduction of unnecessary biopsies in patients with elevated PSA. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e932 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Dennis O'Rourke Boston, MA More articles by this author Daniel DiJohnson Boston, MA More articles by this author Michael O'Leary Boston, MA More articles by this author Jerome Richie Boston, MA More articles by this author Brian Liu Boston, MA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Multiplexed detection and differentiation of the DNA strains for influenza A (H1N1 2009) using a silicon-based microfluidic system

Pandemic influenza by the swine-origin influenza virus (H1N1 2009) has attracted considerable concern worldwide. A convenient and accurate diagnostic approach that can be deployed at the point of care, such as in a doctor's office or at an airport, is critical for disease control. Here we report the development of a silicon-based microfluidic system for subtype differentiation of the novel H1N1 2009 strain vs. the seasonal influenza A (FluA) strain. The proposed system included two functional modules: a multiplexed PCR module for amplification of nucleic acid targets and a multiplexed silicon nanowire (SiNW) module for sequence determination. The PCR module consisted of a microfluidic PCR chamber and an electrical controller to perform a multiplexed protocol that simultaneously enriched specific segments of both H1N1 and FluA strains (if present), with 10 4–10 5 amplification efficiency. The PCR amplicon was subsequently denatured and transferred to the SiNW sensing module for a label-free, multiplexed detection. A control SiNW was implemented, for the first time, in order to eliminate background interference. The detection module demonstrated a 10× change in the magnitude of differential current when the target DNA was injected. Overall, the system achieved a sensitivity of 20–30 fg/μl for H1N1 and seasonal FluA nucleic acids in a 10 μl sample. The low sample consumption, high sensitivity and high specificity render it a potential point-of-care (POC) platform to help doctors reach a yes/no decision for infectious diseases.

Focus on nanoscience and nanotechnology

Focus on nanoscience and nanotechnology

Rapid Determination of Supplemental Vitamin E Acetate in Feed Premixes by Capillary Gas Chromatography

Abstract A rapid capillary gas chromatographic method was developed for determination of supplemental cc-tocopherol acetate (containing and verified at 50–5000 mg/kg feed) in various kinds of feed premixes. The method is based on simple n-hexane extraction of feed samples pretreated with a solution of acetic acid in ether for matrix breakdown followed by column cleanup on deactivated alumina to eliminate background interference. Fused silica chromatography is completed in 3 min. The withinday precision expressed as the relative standard deviation for recovery examples was 3.4,2.9, and 4.0% for high, medium, and low concentrated feed premixes, respectively; extraction recovery was 99–110%. The storage stabilities of standards and feed premix preparations were found to be excellent up to 3 months and up to 60° C.

Determination of low concentrations of lithium in biological samples using electrothermal atomic absorption spectrometry

A method is described for the determination of endogenous lithium concentrations in serum and urine using electrothermal atomic absorption spectrometry. The method has also been applied to the analysis of nanolitre samples of micro-puncture fluid from rat kidney tubules containing pharmacological concentrations of lithium. The graphite tubes are coated in situ with tantalum to give improved sensitivity and increased pre-atomization stability. A mini-flow of gas at a flow-rate of 30 ml min–1 is used during atomization to eliminate background interference. Background correction is not necessary. The characteristic mass is 0.98 pg of lithium. Serum samples are deproteinized with an equal volume of 10% nitric acid before analysis. Urine samples are diluted 5-fold with 5% nitric acid. The normal range of serum lithium is up to 0.39 µmol l–1 and normal urinary excretion is up to 9 µmol over a period of 24 h.

Ultraviolet spectrophotometry for the determination of benperidol by a difference procedure and for the elucidation of its polymorphic structures.

Benperidol contains two chromophores separated by a non-conjugated system. Its ultraviolet absorption spectrum, in acidic or neutral aqueous solution, shows maxima due to the p-fluoroacetophenone chromophore (at 249 nm) and to the benzimidazolone chromophore (at 232 and 279 nm). In alkali, owing to ionisation, there is a bathochromic shift of the benzimidazolone absorption, and peaks occur at 220, 248 and 288 nm. An apparent hyperchromic effect at 248 nm is caused by the overlapping of peaks from the two chromophores. A procedure is proposed for determining benperidol in tablets by measuring the difference in absorbance at 292 nm of solutions prepared in alkali and in acid. This can eliminate background interference, and hence avoid preliminary purification steps.Infrared spectra indicate that benperidol can act as a zwitterion. Ultraviolet absorption spectra of benperidol in organic solvents show marked bathochromic shifts of the longer wavelength benzimidazolone maximum, compared with spectra in acidic or neutral aqueous solution. In ethers, the shift is of the same magnitude as that produced in aqueous alkali and probably indicates hydrogen bonding with the enol form. Alcohols can stabilise the zwitterion by hydrogen bonding with the oxygen of the —NC—O– grouping, which would explain the formation of a polymorph with no amide absorption on recrystallisation from isopropanol.

Evaluation of Snow Water Equivalent by Airborne Measurement of Passive Terrestrial Gamma Radiation

Recent research studies have investigated an airborne gamma radiation detection system to determine the water equivalent of snowpacks in nonmountainous areas. Snow attenuates natural gamma emissions from the soil, and the magnitude of attenuation is related to the mass of the water blanket between the soil and the detector. Gamma spectral and total counting rates are collected and recorded by an airborne system using 14 4‐ by 4‐inch sodium iodide (NaI (Tl)) crystals. These data are corrected for soil moisture, background radiation, and effects of air density. Extensive snow depth and density measurements were taken to determine ‘ground truth’ water equivalent under the flight path. Results of the first year of research indicate that gamma spectral data may be expected to give areal measurement of snow water equivalent within at least 0.2–0.5 inch over favorable terrain. The use of total count data is even more promising but requires methodology still under development for eliminating background interference.