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Spectral discrimination of planktonic cyanobacteria and microalgae based on deep UV fluorescence
摘要： The deep ultraviolet fluorescence characteristics of several cyanobacteria and microalgae are analyzed and exploited for their discrimination in liquid samples. The proposed approach is based on relative fluorescence peak amplitude of natural pigments in cyanobacteria or other planktonic species commonly present in water bodies. The experimental results demonstrate a clear discrimination between the various species of cyanobacteria and other planktonic species. This approach can be simply implemented in fluorescence measurement systems for real-time detection of cyanobacteria, provided that they are able to operate in deep ultraviolet.
关键词： Autofluorescence,Portable sensor,Cyanobacteria,Fluorescence spectroscopy
更新于2025-09-23 15:23:52
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Fundus autofluorescence and spectral domain optical coherence tomography as predictors for long-term functional outcome in rhegmatogenous retinal detachment
摘要： Purpose To detect pre- and postoperative retinal changes in fundus autofluorescence (AF) and spectral domain optical coherence tomography (SD-OCT) and to correlate these with functional outcome in patients with primary rhegmatogenous retinal detachment (RRD). Methods A prospective, 30-month study of patients operated with 25-gauge vitrectomy for primary RRD. Patients were examined preoperatively and after 6 and 30 months, using ultrawide-field AF images (UWFI) (Optos 200Tx) and SD-OCT (Topcon 3D OCT-2000) imaging. Results Of 84 patients (84 eyes) included at baseline, 100.0 and 86.9% were re-examined at month 6 and 30, respectively. Preoperative findings such as macular attachment, detachment > 750 μm from foveola, lack of intraretinal separation, and subfoveal elevation ≤ 500 μm were all associated with better BCVA at months 6 and 30. Postoperative disruption of the photoreceptor layer was associated with poor BCVA at month 6 (p < 0.001) but not at month 30. At baseline, AF-demarcation of RRD was demonstrated by a hyperfluorescent edge in 92.0% and was associated with visual impairment at months 6 (p = 0.003) and 30 (p = 0.003). Visual outcome at month 30 was good (≤ 0.3 logMAR (≥ 20/40 Snellen)), regardless of the preoperative, macular status. However, with significantly better visual outcome in patients with macula attachments versus partly or totally macular detachments (p < 0.001). Conclusion Fundus AF and SD-OCT is able to identify retinal reestablishment up to 30 months after primary RRD, with good correlation to BCVA. These findings emphasize the importance of long-term studies for final visual recovery.
关键词： Fundus autofluorescence,Rhegmatogenous retinal detachment,Long-term outcome,Vitrectomy,Visual outcome,Optical coherence tomography
更新于2025-09-23 15:23:52
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In vivo multiphoton microscopy detects longitudinal metabolic changes associated with delayed skin wound healing
摘要： Chronic wounds are difficult to diagnose and characterize due to a lack of quantitative biomarkers. Label-free multiphoton microscopy has emerged as a useful imaging modality capable of quantifying changes in cellular metabolism using an optical redox ratio of FAD/(NADH+FAD) autofluorescence. However, the utility of an optical redox ratio for long-term in vivo monitoring of tissue metabolism has not been robustly evaluated. In this study, we demonstrate how multiphoton microscopy can be used to monitor changes in the metabolism of individual full-thickness skin wounds in vivo. 3D optical redox ratio maps and NADH fluorescence lifetime images identify differences between diabetic and control mice during the re-epithelialization of wounds. These metabolic changes are associated with a transient increase in keratinocyte proliferation at the wound edge. Our study demonstrates that high-resolution, non-invasive autofluorescence imaging can be performed in vivo and that optical redox ratios can serve as quantitative optical biomarkers of impaired wound healing.
关键词： metabolism,optical redox ratio,autofluorescence,multiphoton microscopy,in vivo imaging,diabetes,FAD,NADH,wound healing
更新于2025-09-23 15:23:52
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Aportaciones de la fluorescencia a la cirugía endocrina
摘要： The use of fluorescence in surgery has expanded and become widespread in recent years, which has led to a real technological phenomenon with the emergence of devices adapted for use in laparoscopic and robotic approaches. Fluorescence-guided surgery in the field of endocrine surgery is also on the rise. More and more articles describe its use in surgery of the thyroid, parathyroid and adrenal glands, although the series are still modest in size and protocols have not been standardized. There are currently several developing areas for the application of fluorescence in endocrine surgery, including the use of fluorescence with indocyanine green in adrenal gland surgery, the identification and prediction of parathyroid perfusion with indocyanine green, and autofluorescence of the parathyroid glands. The objective of this article is to review the current applications of fluorescence in endocrine surgery.
关键词： Thyroid surgery,Parathyroid surgery,Indocyanine green,Endocrine surgery,Fluorescence-guided surgery,Adrenal surgery,Autofluorescence
更新于2025-09-23 15:23:52
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Effect of Fixation and Mounting on Fluorescence Lifetime of Cellular Autofluorescence
摘要： Fluorescence lifetime measurements are often performed on live as well as fixed cells and tissues. Fixation and mounting processes are routinely used in cellular research or clinical diagnosis. In this study, the effects of fixation and mounting on the fluorescence lifetime of cellular autofluorescence were studied by fluorescence lifetime imaging microscopy over fluorophores, reduced fluorescent time. Two endogenous nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), showed different results between live cells and fixed cells. The average lifetime of NADH in live HeLa cells was about 1.02 ns, while maintained about 1.57 ns during the fixation periods of 14 days. The average lifetimes of FAD in live and fixed HeLa cells within 11 days were similar around 1.75 ns but increased to 2.10 ns after 12 days. The free and bound states of the two kinds of fluorophores were further analyzed. It was found that the bound-FAD had two different groups, which was related to the cell division cycle. The effect of mounting medium on fluorescence lifetimes was also studied, indicating glycerol has a negative impact on the fluorescence lifetime compared with neutral balsam.
关键词： fluorescence lifetime,fixed cells,Autofluorescence,mounting medium
更新于2025-09-23 15:23:52
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Portable spectroscopic system for <i>in vivo</i> skin neoplasms diagnostics by Raman and autofluorescence analysis
摘要： This paper studies the applicability of a portable cost-effective spectroscopic system for the optical screening of skin tumors. In vivo studies of Raman scattering and autofluorescence of skin tumors with the 785 nm excitation laser in the near infrared region included malignant melanoma, basal cell carcinoma, and various types of benign neoplasms. The efficiency of the portable system was evaluated by comparison with a highly sensitive spectroscopic system and with the diagnosis accuracy of a human oncologist. Partial least square analysis of Raman and autofluorescence spectra was performed; specificity and sensitivity of various skin oncological pathologies detection varied from 78.9% to 100%. 100% accuracy of benign and malignant skin tumors differentiation is possible only with a combined analysis of Raman and autofluorescence signals.
关键词： autofluorescence,optical biopsy,portable spectroscopic equipment,skin neoplasms,melanoma,partial least square analysis,Raman spectroscopy,malignancy
更新于2025-09-23 15:23:52
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Prediction of DNA concentration in fingermarks using autofluorescence properties
摘要： During criminal investigations trace DNA samples, including fingermarks, are submitted to laboratories for short tandem repeat (STR) analysis. For most common STR analysis systems a minimum amount of input DNA is required. Upon intake by the forensic laboratory the DNA concentration is estimated using quantitative polymerase chain reaction (qPCR) analysis after which most fingermarks are excluded. To tackle the problem of unnecessary processing in the lab, our study aimed to develop a method, which is able to predict the DNA content in fingermarks directly at the crime scene. Upon excitation with a UV Crime-lite, fingermark residues have autofluorescent properties. We hypothesize that the intensity of the autofluorescence signal of the fingermarks correlates to the DNA concentration in fingermarks. In this study, 164 fingermarks were examined on their autofluorescence intensity when excited at 365 nm, the number of nucleated cells, their DNA concentration and the completeness of the STR profiles. No significant correlation was observed between the DNA concentration in fingermarks and the autofluorescence signal, indicating that a high amount of autofluorescence, thus a high amount of biomaterial, does not necessarily guarantee a higher amount of DNA. In addition, the completeness of the STR profiles did not correlate to the autofluorescence signal of fingermarks. A moderate correlation was found between the predicted DNA quantity, based on the number of nucleated cells and the DNA quantity. In summary, the autofluorescence signal of fingermarks cannot directly be used as a guide to select fingermarks for DNA analysis directly at the crime scene. However, predicting the amount of DNA using a sensitive and specific DNA staining method can probably be used to estimate the DNA concentration in touch samples.
关键词： Fingermarks,STR profiling,Autofluorescence,Touch DNA,Forensic science,Nucleated cells
更新于2025-09-23 15:22:29
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The assessment of autofluorescence of the crystalline lens in diabetic patients and healthy controls: can it be used as a screening test?
摘要： Background: Our purpose was to demonstrate if measuring lens autofluorescence (AF) with a scanning confocal biomicroscope may be used to identify subjects with undiagnosed type II diabetes mellitus (DM), and hence, for it to be used as a marker for the severity of diabetic retinopathy in diabetic patients. Patients and methods: In this cross-sectional, comparative study, lens AF was measured with scanning confocal lens fluorescence biomicroscope in diabetic and healthy groups. Full ophthalmological examination was performed. Blood tests of fasting plasma glucose, and glycosylated hemoglobin were also analyzed. The correlation between lens AF results and blood tests was evaluated in both groups. The cutoff value for the diagnosis of DM using lens AF was investigated. Results: The study included 191 subjects with a mean age of 52.09±6.75 years. One hundred and seven (56.0%) subjects were female, and 84 (44.0%) were male. Eighty-two (42.9%) patients had type II DM, and 109 (57.1%) subjects self-reported as normal. The fluorescence ratio (FR) values ranged from 0.09 to 0.46 (0.23±0.06) in the total group. Mean FR measurements of diabetic subjects were significantly higher (0.27±0.06) than those without DM (0.20±0.05), ( p=0.001). A statistically significant correlation was found between glycosylated hemoglobin, fasting plasma glucose, and FR. The cutoff point for the FR according to the presence of DM was found to be 0.24 and above ( p=0.001), with a sensitivity of 71.95% and a specificity of 80.73%. Conclusion: Measuring AF of human lens as an indirect evidence of increased advanced glycation end products may helpful in detecting impaired glucose metabolism. Our results show highly significant correlation between possibility of DM and FR.
关键词： fasting plasma glucose,diabetic retinopathy,screening,HgA1c,lens autofluorescence,diabetes
更新于2025-09-23 15:22:29
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Preliminary analysis of the relationship between serum lutein and zeaxanthin levels and macular pigment optical density
摘要： Purpose: To assess the relationship between combined serum lutein and zeaxanthin (L+Z) concentration and macular pigment optical density (MPOD), and to investigate the effect of L+Z+docosahexaenoic acid (DHA) dietary supplementation on the spatial distribution of MPOD. Methods: Twenty healthy fellow eyes with unilateral wet age-related macular degeneration or chronic central serous chorioretinopathy were included. All participants received a dietary supplement for 6 months that contained 20 mg L, 1 mg Z, and 200 mg DHA. The best-corrected visual acuity and contrast sensitivity (CS) were measured at baseline and at 1, 3, and 6 months. Serum L+Z concentrations were measured at baseline and at 3 months. MPOD was calculated at each time point using fundus autofluorescent images. Results: Serum L+Z concentration was correlated with MPOD at 1°–2° eccentricity at baseline (r=0.63, P=0.003) and 3 months (r=0.53, P=0.015). Serum L+Z concentration increased by a factor of 2.3±1.0 (P<0.0001). At 6 months, MPOD was significantly higher compared to the baseline level at 0°–0.25° (P=0.034) and 0.25°–0.5° (P=0.032) eccentricity. CS improved after 3 or 6 months of L+Z+DHA supplementation (P<0.05). Conclusion: Juxtafoveal MPOD was associated with serum L+Z concentration. Foveal MPOD was increased by L+Z+DHA dietary supplementation.
关键词： fundus autofluorescence,spatial distribution,supplement
更新于2025-09-23 15:22:29
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Bartonella Neuroretinitis: A Case Report with New Insights from Fundus Autofluorescence Imaging
摘要： Purpose: Fundus autofluorescence (FAF) is a modern functional imaging modality utilized to characterize abnormalities of the retinal pigment epithelium (RPE). There are no prior studies demonstrating FAF findings in both symptomatic and asymptomatic eyes of patients diagnosed with Bartonella neuroretinitis. Methods: Case report and review of the literature. Patients: Single patient case study. Results: In the symptomatic right eye, (FAF-Heidelberg Retina Angiograph; Heidelberg Engineering, Heidelberg, Germany) identified abnormality of the RPE which corresponded to pathology seen on fundus photography, fluorescein angiography (FA-Heidelberg Retina Angiograph; Heidelberg Engineering, Heidelberg, Germany) and spectral domain optical coherence tomography (SD-OCT-Spectralis?, Heidelberg Engineering, Heidelberg, Germany). Interestingly, FAF also demonstrated sub-clinical anatomic abnormalities not seen clinically nor detected as clearly by any other imaging modalities in the patient’s asymptomatic left eye. As the patient improved clinically, normalization of the FAF occurred in both eyes. Discussion: This report is the first study to describe novel subclinical and clinical FAF findings as part of the evaluation of a patient with infectious neuroretinitis. Compared to FA, SD-OCT and clinical examination, FAF provided a more detailed functional understanding of this condition in its early stages and was also used to follow the clinical course of this patient. This functional imaging modality confirmed normalization of anatomic abnormalities also demonstrated by the other techniques.
关键词： Neuroretinitis,Bartonella,Autofluorescence
更新于2025-09-23 15:21:21