- 标题
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A dual colorimetric and near-infrared fluorescent turn-on probe for Hg2+ detection and its applications
摘要： The increasing Hg2+ contamination in environment and ecosystem has gained wide attention and thus demands for its facile and effective detection. In this study, we constructed a new fluorescent probe (E)-2-(2-(3-(1,3-dithian-2-yl)-4-hydroxystyryl)-4H-chromen-4-ylidene)malononitrile (DCM-Hg) for Hg2+ detection by incorporating the 1, 3-dithiane group to the dicyanomethylene-4H-pyran fluorophore for the first time. This probe can selectively detect Hg2+ via the Hg2+-triggered deprotection reaction of thioacetals, which leads to a distinct color change from purple to pink and obvious fluorescence enhancement in the near-infrared (NIR) region. The NIR fluorescence intensity increased linearly with Hg2+ level within the range from 0 to 100 μM and the detection limit of DCM-Hg for Hg2+ was found to be 6.8 × 10-8 mol/L. Moreover, the probe could sense Hg2+ on paper strips and image Hg2+ in living cells with low cytotoxicity, which demonstrates its potential application in environment and biological science.
关键词： Selectivity,Near-infrared,Imaging,Color change,Hg2+
更新于2025-09-23 15:21:01
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Rapid analysis of food raw materials adulteration using laser direct infrared spectroscopy and imaging
摘要： The objective of this study was to assess the application of the Laser Direct Infrared (LDIR) imaging system as a rapid screening technology for detection, identification, and semi-quantitation of adulterants in food ingredients. Forty-five samples of skimmed milk powder, thirty-one samples of soy protein isolate, thirty-five samples of chicken meat powder, thirty-two samples of pea protein isolate and six samples of wheat flour were dry blended adulterated with nitrogen-rich compounds and bulking agents at concentrations of 1.0 to 15.0% (w/w). In addition, ten samples of skimmed milk powder were wet blended with food adulterants at 5.0% and 10.0% (w/w) to check the LDIR performance when different fraudulent processes are applied. The results from this study shows that LDIR can be used as a rapid untargeted screening method that are independent of adulterants to detect, identify and semi-quantify food adulterants in dry blended samples. In most samples, the technology accurately identified all nitrogen-rich compounds and bulking agents present in the dry blended samples. In addition, the technology shows sensitivity of 82% for samples adulterated at 1% and sensitivity from 92% to 100% for samples adulterated at ≥ 5% economic adulteration. On the other hand, the detection and identification of food adulterants in samples prepared by wet blending process was more challenging than dry blended samples because mid-infrared technology may not be sensitive enough to detect adulterants if they are dissolved or if hidden within the particles.
关键词： Food adulteration,mid-infrared,laser direct infrared imaging,vibrational spectroscopy,untargeted method,raw materials
更新于2025-09-23 15:19:57
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IGCS Intraoperative Technology Taskforce. Update on near infrared imaging technology: beyond white light and the naked eye, indocyanine green and near infrared technology in the treatment of gynecologic cancers
摘要： Surgery, by its very nature, relies on the ability of the surgeon to visualize and distinguish healthy and non-healthy tissue or structures. Without advanced technology, surgeons can visualize only that which can be seen with the naked eye or using white light imaging. Critical information on tissues, anatomical structures and physiological processes remain hidden and difficult to discern. Fluorescence imaging augments the basic surgical information. This form of imaging entails injecting a contrast or fluorescence agent (fluorophore) that is then illuminated by the appropriate wavelength of light required to excite the fluorophore. The excited fluorophore emits light of a slightly longer wavelength that is selectively imaged to produce a fluorescence image. The first fluorescent agent used in surgery was an intravenous injection of fluorescein, where it was used to enhance intracranial neoplasms. One particular imaging agent, indocyanine green, has been a significant driver of adoption of fluorescence imaging. Indocyanine green was first developed in 1955 by Kodak Research Laboratories and was approved by the Food and Drug Administration (FDA) in 1959 for retinal angiography. Since that time, this fluorophore has been used for a variety of surgical applications due to its unique properties: relative non-toxicity, depth of visualization through tissue, and remaining confined to intravascular and lymphatic spaces due to binding predominately to lipoproteins. The large depth of visualization results from the fluorescence properties of bound indocyanine green which is optimally excited with 805 nm light and emits over an approximate wavelength range from 810 nm to 875 nm. These near infrared wavelengths, invisible to the naked eye, pass through tissue particularly well due to the low adsorption of light by the various structures of tissue, such as hemoglobin and water. As a result, the tissue is relatively transparent to this light and images of structures as much as 5 mm below the tissue surface can be formed. By comparison, fluorescence imaging with fluorescein images only 2–3 mm below the tissue surface; thus subsurface structures cannot be imaged using visible fluorophores.
关键词： gynecologic cancers,fluorescence imaging,indocyanine green,near infrared imaging,surgical technology
更新于2025-09-23 15:19:57
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Effect of point spread function position bias in wavefront coding infrared imaging system
摘要： By an experimental finding, for a given radiant point source and a given infrared detector sampling, an optical point spread function (PSF) falling on different positions of an infrared detector focal plane array, will result in different measured PSFs. Those measured PSFs known as decoding kernels will further produce different decoded images. Therefore, this work explores the effect of PSF position bias on decoded images in a wavefront coding infrared imaging system. This paper theoretically analyzes the effect of PSF position bias on decoded images. A simulation is conducted for qualitatively evaluating the effect of PSF position bias on decoded images by mean structural similarity (MSSIM) index. Simulated results prove that the probability for MSSIM index greater than 0.75 is 91.38%, and that for less than 0.5 is only 1.22% but this minority seriously degrades the decoded images. We construct an experimental setup for capturing the raw PSF image at a random position and proposes a procedure to reduce the noise of a raw PSF image. The experimental result demonstrates the feasibility for measuring a PSF to achieve a decoded image with good quality.
关键词： infrared imaging,PSF,wavefront coding,position bias,decoded image
更新于2025-09-23 15:19:57
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A 3D Mask Presentation Attack Detection Method Based on Polarization Medium Wave Infrared Imaging
摘要： Facial recognition systems are often spoofed by presentation attack instruments (PAI), especially by the use of three-dimensional (3D) face masks. However, nonuniform illumination conditions and significant differences in facial appearance will lead to the performance degradation of existing presentation attack detection (PAD) methods. Based on conventional thermal infrared imaging, a PAD method based on the medium wave infrared (MWIR) polarization characteristics of the surface material is proposed in this paper for countering a flexible 3D silicone mask presentation attack. A polarization MWIR imaging system for face spoofing detection is designed and built, taking advantage of the fact that polarization-based MWIR imaging is not restricted by external light sources (including visible light and near-infrared light sources) in spite of facial appearance. A sample database of real face images and 3D face mask images is constructed, and the gradient amplitude feature extraction method, based on MWIR polarization facial images, is designed to better distinguish the skin of a real face from the material used to make a 3D mask. Experimental results show that, compared with conventional thermal infrared imaging, polarization-based MWIR imaging is more suitable for the PAD method of 3D silicone masks and shows a certain robustness in the change of facial temperature.
关键词： presentation attack detection,polarization medium wave infrared imaging,three-dimensional silicone mask,gradient amplitude feature
更新于2025-09-23 15:19:57
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Infrared fluorescence imaging of infarcted hearts with Ag2S nanodots
摘要： Ag2S nanodots have already been demonstrated as promising near-infrared (NIR-II, 1.0–1.45 μm) emitting nanoprobes with low toxicity, high penetration and high resolution for in vivo imaging of, for example, tumors and vasculature. In this work, we have systematically investigated the potential application of functionalized Ag2S nanodots for accurate imaging of damaged myocardium tissues after a myocardial infarction induced by either partial or global ischemia. Ag2S nanodots surface-functionalized with the angiotensin II peptide (ATII) have shown over 10-fold enhanced binding efficiency to damaged tissues than non-specifically (PEG) functionalized Ag2S nanodots due to their interaction with the upregulated angiotensin II receptor type I (AT1R). It is demonstrated how the NIR-II images generated by ATII-functionalized Ag2S nanodots contain valuable information about the location and extension of damaged tissue in the myocardium allowing for a proper identification of the occluded artery as well as an indirect evaluation of the damage level. The potential application of Ag2S nanodots in the near future for in vivo imaging of myocardial infarction was also corroborated by performing proof of concept whole body imaging experiments.
关键词： Ag2S,biological windows,infrared imaging,Langendorff heart,myocardial infarct,nanodots
更新于2025-09-19 17:15:36
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Fluorescence-Guided Neurosurgery (Neuro-oncology and Cerebrovascular Applications) || 1 Current Fluorescence-Guided Neurosurgery and Moving Forward
摘要： This introductory chapter provides a current overview of fluorescence-guided neurosurgery and includes future directions. The concepts of fluorescence and fluorescence-guided surgery (FGS) are introduced. Currently used fluorescent contrast agents in patients are summarized, including 5-aminolevulinic acid (5-ALA), fluorescein, and indocyanine green. Excitation light sources are discussed for each fluorescent contrast agent. Targeted fluorophores under clinical development for FGS are also introduced. Future directions in fluorescence-guided neurosurgery including handheld devices to better detect tumor fluorescence, dual fluorophore imaging, metabolic imaging in combination with FGS, and detection of the tumor margin will be discussed.
关键词： near-infrared imaging,fluorophore,indocyanine green,fluorescence-guided neurosurgery,fluorescence,operative microscope,fluorescence-guided surgery,fluorescein sodium,5-ALA
更新于2025-09-19 17:15:36
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Ex-vivo Imaging of Upper Tract Urothelial Carcinoma Using Novel ICG-Var3 pHLIP Imaging Agent
摘要： Objectives: To improve visualization of upper tract urothelial carcinomas (UTUC). Previous studies using the novel pH low insertion peptide (pHLIP) variant 3 (Var3) conjugated to indocyanine green (ICG) have demonstrated high sensitivity and specificity for imaging of bladder urothelial carcinoma. Here, we describe a novel approach for the imaging of UTUC using ICG-Var3 pHLIP. Methods: Twelve ex-vivo upper urinary tract specimens were irrigated with ICG-Var 3 pHLIP for fifteen minutes and then examined using a white light laparoscopic camera followed by near infrared fluorescent (NIRF) imaging using a Stryker 1588 AIM imaging system. Standard histopathologic evaluation was performed and findings were correlated with white light and ICG-Var3 NIRF imaging. One patient who underwent radical nephrectomy for renal cell carcinoma was used as a negative control. Results: Nineteen lesions were identified on histopathologic evaluation in ten patients, including 82% high-grade urothelial carcinoma and 18% low-grade urothelial carcinoma. Nineteen (100%) malignant lesions were identified using NIRF imaging, while 15 (78.9%) lesions were identified using conventional white light examination. The sensitivity of ICG-Var3 pHLIP NIRF imaging was 100% compared to 78.9% white light examination. Both modalities are 100% specific. Benign collecting systems and ureters did not show uptake of the pHLIP construct. Conclusions: In this feasibility study, the ICG-Var3 pHLIP imaging agent demonstrated superior diagnostic performance compared to conventional white light examination. While additional studies are required for validation and in-vivo translation, pHLIP-based imaging represents a promising tool to improve the evaluation and management of upper tract urothelial carcinoma.
关键词： urothelial carcinoma,pHLIP,fluorescence,NIRF,near infrared imaging
更新于2025-09-19 17:15:36
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Mixed-dimensional PdSe <sub/>2</sub> /SiNWA heterostructure based photovoltaic detectors for self-driven, broadband photodetection, infrared imaging and humidity sensing
摘要： The new discovery of two-dimensional (2D) palladium diselenide (PdSe2) films has attracted intensive research interest due to their unique asymmetric crystal structure and extraordinary optoelectronic properties, showing great potential for broadband and polarization photodetection. Herein, we have developed for the first time a self-driven, highly polarization-sensitive, broadband photovoltaic detector based on a PdSe2/Si nanowire array (SiNWA) heterostructure. Owing to the strong light confinement effect of the SiNWA and broadband light absorption of PdSe2, the present device exhibits pronounced photovoltaic behavior and excellent performance in terms of a high responsivity of 726 mA W?1, a large specific detectivity of 3.19 × 1014 Jones, an ultrabroad spectrum response range of 0.2–4.6 mm, and a fast response speed to monitor nanosecond pulsed light signals. Significantly, an impressive polarization sensitivity of 75 is achieved for the heterostructure device, which is among the highest for 2D material-based photodetectors. Thanks to the outstanding imaging capability, the detector can record images in both near infrared (NIR) and mid-infrared (MIR) ranges with a decent resolution. Moreover, the device exhibits light-enhanced humidity sensing behavior with a high sensitivity and a fast response/recovery time. Given these remarkable device features, the PdSe2/SiNWA heterostructure will hold great promise for high-performance, polarization-sensitive broadband photodetection, infrared imaging and humidity sensing applications.
关键词： humidity sensing,SiNWA,infrared imaging,photovoltaic detector,heterostructure,broadband photodetection,PdSe2
更新于2025-09-19 17:13:59
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Occurrence frequencies and regional variations in Visible Infrared Imaging Radiometer Suite (VIIRS) global active fires
摘要： Active fires are considered to be the key contributor to, and critical consequence of, climate change. Quantifying the occurrence frequency and regional variations in global active fires is significant for assessing carbon cycling, atmospheric chemistry, and post-fire ecological effects. Multi-scale variations in fire occurrence frequencies have still never been fully investigated despite free access to global active fire products. We analyzed the occurrence frequencies of Visible Infrared Imaging Radiometer Suite (VIIRS) active fires at national, pan-regional (tropics and extra-tropics) to global scales and at hourly, monthly, and annual scales during 2012-2017. The results revealed that the accumulated occurrence frequencies of VIIRS global active fires were up to 12,193×104, yet exhibiting slightly fluctuations annually and with respect to the 2014-2016 El Ni?o event, especially in 2015. 35.52% of VIIRS active fires occurred from July to September, particularly in August (13.06%), and typically between 10:00 Greenwich Mean Time (GMT) and 13:00 GMT (42.96%) and especially at 11:00 GMT (17.65%). The total counts conform to a bimodal pattern with peaks in 5°-11°N (18.01%) and 5°-18°S (32.46%), respectively, alongside a unimodal distribution in terms of longitudes between 15°E and 30°E (32.34%). Tropical annual average of active fire (1,496.81×104) accounted for 75.83%. Nearly 30% were counted in Brazil, the Democratic Republic of the Congo (DRC), Indonesia and Mainland Southeast Asia (MSEA). Fires typically occurred between June (or August) and October (or November) with far below-average rainfall in these countries, while those in MSEA primarily occurred between February and April during the dry season. They were primarily observed between 00:00 GMT and 02:00 GMT, between 12:00 and 14:00 within each Zone Time. We believed that VIIRS global active fires products are useful for developing fire detection algorithms, discriminating occurrence types and ignition causes via correlation analyses with physical geographic elements, and assessment their potential impacts.
关键词： Active fires,Tropical region,Occurrence frequency,Spatio-temporal characteristics,Visible Infrared Imaging Radiometer (VIIRS)
更新于2025-09-19 17:13:59