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Hard exudate based severity assessment of diabetic macular edema from retinal fundus images
摘要： Diabetic macular edema (DME) is a consequence of diabetic retinopathy characterised by the abnormal accumulation of fluid and protein deposit in the macula region of the retina. Prior disclosure of even a trivial trace of DME is essential as it could consequently lead to blurred vision. DME can be diagnosed by the presence of exudates (glossy lesions) in the retinal fundus images. In this work, OD and macula are detected using morphological operation and hard exudates are segmented. Exudates are classified using early treatment diabetic retinopathy standard as normal, moderate or severe cases. The proposed work also incorporates the extraction of various features from the retinal fundus image. Various textural and exudate features are extracted and fed to a classifier to detect DME. Experiments are performed on a publically available database. Performance is evaluated with metrics like accuracy, sensitivity, specificity and accuracy. The results obtained are promising.
关键词： DME,random forest,hard exudates,diabetic macular edema,classification,macula,feature extraction,optic disc
更新于2025-09-04 15:30:14
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Synthesis and Characterization of Tio2/C Composite for Photocatalytic Degradation of Dyes.
摘要： Titanium dioxide TiO2 nanoparticles have moderate catalytic activity due to its wide band-gap and high rate of electron-hole recombination [1]. The TiO2 electrical conductivity poor is improved by mixing with other materials. Therefore, TiO2 based nanocomposites have been synthesized to increase the photocatalytic activity, as well as their structural characteristics and electrochemical performance, using dopants like carbon, nitrogen, sulfur and others. TiO2/C composite has been proven to be a promising photocatalyst for pollutants, due to C-doping, morphology, structure and mixed phases [1]. Carbon precursors are reported to synthesize TiO2/C, such as: glucose, oleic acid, carbon nanofiber, graphene oxide, activated carbon, carbon nanotubes, graphite, resorcinol and formaldehyde. Dyes used for industries, are significant sources of environmental pollution, because they are non-biodegradable [2]. Methyl orange (MO) and methyl blue (MB) have been used to help determine the activity of the photocatalyst [3]. The reagents used were: anatase powder 99.8% (metals basis), sucrose (99.5%), H2SO4 (65% wt), distilled water, MO (MW=327.33g/mol) and MB (MW=319.85g/mol). TiO2/C composites were synthesized via infiltrating sucrose into anatase. In a typical synthesis, anatase (A) and sucrose (S) with molar ratio of A/S=6, sulfuric acid and distilled water were mixed completely. The mixture was then put in a drying oven, treated at 100°C for 6h and subsequently at 160°C for 6h. The resulting brown precursor powder was carbonized in a tubular furnace at 800°C for 1h in argon atmosphere. Rigaku D-Max 2200 difractometer was used to obtain XRD patterns using Cu Kα radiation. The surface morphology and the crystalline phases were examined with Field Emission Transmission Electron Microscope, JEM 2010F JEOL. The photocatalytic activity was tested for degradation of MB and MO with an initial concentration of 20 ppm, using 0 and 0.34 g/L of TiO2/C, under radiant flux provided by 175 W UV. The MB and MO concentrations were measured by UV–vis spectroscopy (Aiglet-Vis spectrophotometer). The XRD patterns of TiO2/C composite is shown in Fig. 2, in which all the characteristic diffraction peaks of the TiO2/C composite can be respectively indexed with planes of anatase phase of TiO2 (JCPDS No. 21-1272). Moreover, a small peak at 11.5° is observed, characteristic of weakly ordered graphitic microstructure, indicating the trace amount of graphite in the composite [4]. No significant peaks of carbon or rutile are observed after the precursor powders are heat treated under argon atmosphere, which suggesting its amorphous nature and confirmed the high purity of the TiO2/C composite [5], because impurities have been reported due to the transformation from anatase to rutile phase [1]. The broad diffraction peaks indicate the sample’s nanocrystalline nature. Fig. 3a shows the micrographs of TEM bright field of powders; it is clearly seen that the TiO2/C composite powders have mostly spherical morphology. Further, it can be estimated that the particle size of samples is of the microscale order with grain size of the range of 20-30nm. Fig. 3b shows the atomic structure and the crystallinity of TiO2/C composite through HRTEM. The insert image shown in Figure 3b give the corresponding Fast Fourier Transform (FFT) pattern of the anatase; this pattern displays (101) and (200) planes from the interplanar spacing of 0.352 and 0.189 nm respectively (JCPDS No. 21-1272). The results of XRD concurred with the electron diffraction pattern created by FFT from HRTEM. The degradation percentage for MO and MB were 99.95 and 99.99 % at 15 min on TiO2/C whereas 86 and 81 % at 90 min for MB and MO in the absence of catalyst is illustrated in Fig. 5. TiO2/C composite was synthetized using anatase and sucrose by obtaining a precursor powder at low temperature (160°C), which is carbonized at 800°C in argon atmosphere. The XRD analysis reveals that the TiO2/C composite is a phase anatase unique structure with high crystallization, which had no impurities, but it showed a trace amount of graphite in the composite. The TiO2/C composite were found to be efficient catalyst for the photodegradation of MB and MO dyes under UV irradiation. The reaction was found to follow pseudo-first order kinetics described it well. This method could be extended to synthesize a variety of other composites for photocatalytic degradation of dyes.
关键词： anatase,TiO2/C composite,dyes,photocatalytic degradation,sucrose
更新于2025-09-04 15:30:14
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How light traverses the inverted vertebrate retina
摘要： In our eyes, as in the eyes of all vertebrates, images of the environment are projected onto an inverted retina, where photons must pass through most of the retinal layers before being captured by the light-sensitive cells. Light scattering in these retinal layers must decrease the signal-to-noise ratio of the images and thus interfere with clear vision. Surprisingly however, our eyes display splendid visual abilities. This apparent contradiction could be resolved if intraretinal light scattering were to be minimized by built-in optical elements that facilitate light transmission through the tissue. Indeed, we were able to show that one function of radial glial (Müller) cells is to act as effective optical fibers in the living retina, bypassing the light-scattering structures in front of the light-sensitive cells. Each Müller cell serves as a ‘private’ light cable, providing one individual cone photoreceptor cell with its appropriate pixel of the environmental image, thus optimizing special resolution and visual acuity.
关键词： Photoreceptor cells,Glial cells,Visual acuity,Scattering,Vision
更新于2025-09-04 15:30:14
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An Application for Descriptive Nearness: Iris Recognition
摘要： Near Set Theory has various applications in the literature. In this paper, using the concept descriptive nearness, we show how to perform iris recognition. This process has a few algorithms given via Mathematica Script Language.
关键词： iris recognition,descriptive nearness,Near set
更新于2025-09-04 15:30:14
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Ultraviolet Solar Spectral Irradiance Variation on Solar Cycle Timescales
摘要： Ultraviolet (UV) Solar spectral Irradiance (SSI) has been measured from orbit on a regular basis since the beginning of the space age. These observations span four Solar Cycles, and they are crucial for our understanding of the Sun-Earth connection and space weather. SSI at these wavelengths are the main drivers for the upper atmosphere including the production and destruction of ozone in the stratosphere. The instruments that measure UV SSI not only require good pre?ight calibration, but also need a robust method to maintain that calibration on orbit. We will give an overview of the catalog of current and former UV SSI measurements along with the calibration philosophy of each instrument and an estimation of the uncertainties in the published irradiances.
关键词： Sun: activity,Sun: UV radiation,instrumentation: spectrographs
更新于2025-09-04 15:30:14
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Electrogenerated Chemiluminescent Chemodosimeter Based on a Cyclometalated Iridium(III) Complex for Rapid and Sensitive Detection of Thiophenol
摘要： Thiophenol is the simplest aromatic thiol that is utilized for various applications in industry and agriculture. However, it should be used with care because thiophenol is readily absorbed into the human body by inhalation and ingestion, which leads to serious internal injuries. Thus, there is an urgent need for real-time and accurate monitoring of thiophenol. Despite remarkable advantages of electrogenerated chemiluminescence (ECL) analysis, ECL thiophenol probes have never been reported. Herein, a new strategy for the rapid detection of thiophenol using an ECL turn-on chemodosimeter based on a cyclometalated Ir(III) complex is described. This analytical system showed superior sensitivity (limit of detection (LOD) value, 3.8 nM) in comparison to the conventional fluorescence method. In addition, our system exhibited remarkable selectivity and reaction rate towards thiophenol over other analytes. Moreover, it was successfully applied to quantify thiophenol in real water samples, providing a new proof-of-concept for field-monitoring based on ECL.
关键词： Cyclometalated Ir(III) complex,Electrogenerated chemiluminescence,Chemodosimeter,Sensitive detection,Thiophenol
更新于2025-09-04 15:30:14
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Desenvolvimento de filmes poliméricos ultrafinos e reticulados para aplica??es em sensores
摘要： A new method for producing stable films used in sensors is proposed, based on the layer-by-layer deposition of poly(o-ethoxyaniline) and phenol-formaldehyde (POEA/PF) followed by a thermal treatment to promote film crosslinking. The crosslinking process was characterized by Fourier transform infrared and ultraviolet-visible spectroscopic analyses, atomic force microscopy and desorption studies. Sensor analyses were also carried out in order to evaluate cross-linked sensor signal. Results showed that PF resin served as a curing agent, forming a semi-interpenetrating polymer network therefore producing stable films. Although there was a decrease in the sensitivity of sensors with crosslinking, such films are quite stable and can be potentially used in sensors, especially where higher stability is required.
关键词： ultrathin films,conductive polymers,sensors
更新于2025-09-04 15:30:14
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Toxicity effects of nickel electroplating effluents treated by photoelectrooxidation in the industries of the Sinos River Basin
摘要： The Sinos river Basin is an industrial region with many tanneries and electroplating plants in southern Brazil. The wastewater generated by electroplating contains high loads of salts and metals that have to be treated before discharge. After conventional treatment, this study applied an advanced oxidative process to degrade organic additives in the electroplating bright nickel baths effluent. Synthetic rinsing water was submitted to physical-chemical coagulation for nickel removal. The sample was submitted to ecotoxicity tests, and the effluent was treated by photoelectrooxidation (PEO). The effects of current density and treatment time were evaluated. The concentration of total organic carbon (TOC) was 38% lower. The toxicity tests of the effluent treated using PEO revealed that the organic additives were partially degraded and the concentration that is toxic for test organisms was reduced.
关键词： toxicity,nickel plating effluent,photoelectrooxidation,organic additives
更新于2025-09-04 15:30:14
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Co-localization coefficients of a target-switchable fluorescent probe can serve as an indicator of mitochondrial membrane potential
摘要： The mitochondrial membrane potential (MMP) definitely reflects mitochondrial function. Thus, it is very essential to found a physical parameter as MMP indicator. At present, available parameters are either fluorescent intensity of monochromatic probes such as rhodamine 123 or a ratio of fluorescent intensity at different wavelengths of dual-color dyes such as JC-1, but the inconvenience in practice as well as serious effect of loading concentrations on experimental results limited their application. To address this concern, herein, we found a reliable and easily obtainable co-localization coefficient (CLC) of a fluorescent probe as new MMP indicator and developed a target switchable fluorescent probe (Mito-Lyso) to attain the aim. Due to intrinsic nature, Mito-Lyso exclusively stains mitochondria with normal MMP and a subsequent decreasing of MMP results in release of some Mito-Lyso. Importantly, the released Mito-Lyso can reversibly transfer between mitochondria and lysosomes. Thus, CLCs of Mito-Lyso and a commercial lysosomal probe (NIR-Lyso) can be MMP-dependent. CLCs gradually increased from 0.20 to 0.8 with the decreasing of MMP and then returned to 0.3 with the recovering of MMP, which better proves that the CLC is a valuable MMP indicator. Furthermore, both the design principle and action mechanism of Mito-Lyso has been explained in detail for the development of this type of probes.
关键词： Mito-Lyso,fluorescent probe,co-localization coefficient,mitochondrial membrane potential,target-switchable
更新于2025-09-04 15:30:14
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Efficiency of portable chlorophyll meters in assessing the nutritional status of wheat plants
摘要： The objective of this study was to verify the efficiency of two portable chlorophyll meters (Minolta SPAD? 502 and Falker ClorofiLOG? 1030) in assessing the nutritional status of wheat plants, correlating the indices from the devices and the direct determination of chlorophyll content with the concentration of nitrogen (N) in the plant. The experiment was conducted in a greenhouse, in pots with 5 dm3 of Oxisol, in a completely randomized design, with six N doses (0, 80, 160, 240, 320 and 400 mg dm-3) and five replicates. At 47 days after emergence, the readings of SPAD and Falker indices and the quantification of chlorophyll content and N concentration in wheat plants were performed, as well as analysis of variance and correlation test, both at 0.05 probability level. The chlorophyll meters Minolta SPAD? 502 and Falker ClorofiLOG? 1030 do not differ with respect to the indirect determination of chlorophyll in wheat plants. The Falker chlorophyll index was statistically equal to the chlorophyll content. Indirect chlorophyll indices and chlorophyll content showed a high correlation with the N concentration in the plant.
关键词： SPAD,Triticum aestivum,Falker
更新于2025-09-04 15:30:14