Characteristic Fluorescence Spectra Research Articles

Enzyme-assisted upconversion fluorescence-encoded biosensing system for simultaneous detection of multiple sites EGFR mutation.

Epidermal growth factor receptor (EGFR) mutations play a key role in the development of a variety of cancers. Rapid detection and screening of EGFR mutation types in patients are of great significance for early treatment of patients. In this study, a highly sensitive fluorescent biosensing system based on lanthanide ion-doped multi-type upconversion nanoparticles (UCNPs) combined with polymerization reaction signal amplification was designed and constructed for the simultaneous detection of L858R and 19Del mutations. Two upconversion nanoparticles (NaYF4:Yb, Er and NaYF4:Yb, Tm) with unique upconversion fluorescence profiles were first prepared using Er and Tm as activators, respectively. Subsequently, the UCNPs were enriched by cDNA complementary hybridization and atom transfer radical polymerization (ATRP) reactions to enhance the signal. Next, the tDNA/cDNA hybrids were cleaved using specific restriction endonucleases to detach UCNPs aggregates from the surface of the magnetic beads. Finally, the fluorescence signal in the supernatant was detected after magnetic separation. The simultaneous quantitative detection of the two EGFR mutations was achieved by analyzing the changes in signal intensity of the characteristic upconversion fluorescence spectra of the two encoded UCNPs at their respective emission peaks. The detection range of the method was from 10 fM to 10nM, and the detection limits were 2.44 fM for L858R and 2.13 fM for 19Del. The sensing system was able to effectively differentiate between wild-type and other mutation types, and its detection results were consistent with qPCR. The excellent performance of the sensor suggests its promising application in the diagnosis and precision treatment of NSCLC.

Exploring Riboflavin Quantification in Honey via Spectrofluorimetry: A Statistical Examination of Influential Extrinsic Variables

Background: The present study is focused on the collection of honey samples from the different geographical and climatic conditions of Khyber Pakhtunkhwa and analyzing them for the determination of riboflavin. Quantification of riboflavin, being natively fluorescent, was accomplished using spectrofluorimetric method. Riboflavin has characteristic fluorescence spectra with maximum excitation at 464 nm followed by an emission peak at 525 nm. Method: The procedure followed in this work comprised the construction of a calibration curve by plotting the fluorescence intensity of a series of riboflavin solutions versus concentration. This curve was used for the quantification of riboflavin in the collected honey samples. The effect of several external factors such as the altitude of the sampling area, type of honey bee, type of flowers from which the nectar was collected, and sampling season on the concentration of riboflavin in the honey samples was statistically evaluated. Results and Discussion: It was concluded that the samples collected from lower altitudes have high concentrations (1.156±0.08 μg g-1) of riboflavin. Similarly, the samples collected in autumn were found to have a maximum average riboflavin concentration of 1.37±0.06 μg g-1, which was higher in comparison to the samples collected in other seasons of the year. Likewise, the effect of flora on the concentration of riboflavin was also investigated and it was found that honey samples collected from areas where the nectar was collected from Ziziphus contains maximum riboflavin concentration averaged at 1.383±0.1 μg g-1. Conclusion: Based on the size of the honey bees, the samples collected from hives of small honey bees were found to have a maximum riboflavin concentration of 1.176±0.07 μg g-1. This study suggests that besides the studied vitamin, the rest of the vitamins and other nutritional components may vary in the honey samples depending upon external factors. conclusion: It was concluded that the samples collected from lower altitudes have high concentration (1.156±0.08 μg g-1) of riboflavin. Similarly, the samples collected in autumn were found to have a with a maximum average riboflavin concentration of 1.37±0.06 μg g-1, which was higher in comparison to the samples collected in other seasons of the year. Likewise, the effect of flora on the concentration of riboflavin was also investigated and it was found that honey samples collected from areas where the nectar was collected from Ziziphus contains maximum riboflavin concentration averaged at 1.383±0.1 μg g-1. Based on the size of the honey bees the samples collected from hives of small honey bees were found to have maximum riboflavin concentration of 1.176±0.07 μg g-1. This study suggests that beside the studied vitamin, the rest of the vitamins and other nutritional components may vary in the honey samples depending upon external factors.

Flexible Physical Unclonable Functions Based on Non-deterministically Distributed Dye-Doped Fibers and Droplets.

The development of new anticounterfeiting solutions is a constant challenge and involves several research fields. Much interest is currently devoted to systems that are impossible to clone, based on the physical unclonable function (PUF) paradigm. In this work, a new strategy based on electrospinning and electrospraying of dye-doped polymeric materials is presented for the manufacturing of flexible free-standing films that embed simultaneously different PUF keys. The proposed films can be used to fabricate novel anticounterfeiting labels having three encryption levels: (i) a map of fluorescent polymer droplets, with random positions on a dense yarn of polymer nanofibers, (ii) a characteristic fluorescence spectrum for each label, and (iii) the unique speckle patterns that every label produces when illuminated with coherent laser light shaped in different wavefronts. The intrinsic uniqueness introduced by the manufacturing process encodes enough complexity into the optical anticounterfeiting tag to generate thousands of cryptographic keys. The simple and cheap fabrication process as well as multilevel authentication makes such colored polymeric unclonable tags a practical solution in the secure protection of goods in our daily life.

Altered lipid acyl chain length controls energy dissipation in light-harvesting complex II proteoliposomes by hydrophobic mismatch.

In plants, the major light-harvesting antenna complex (LHCII) is vital for both light harvesting and photoprotection in photosystem II. Previously, we proposed that the thylakoid membrane itself could switch LHCII into the photoprotective state, qE, via a process known as hydrophobic mismatch. The decrease in the membrane thickness that followed the formation of ΔpH was a key fact that prompted this idea. To test this, we made proteoliposomes from lipids with altered acyl chain length (ACL). Here, we show that ACL regulates the average chlorophyll fluorescence lifetime of LHCII. For liposomes made of lipids with an ACL of 18 carbons, the lifetime was ∼2ns, like that for the thylakoid membrane. Furthermore, LHCII appears to be quenched in proteoliposomes with an ACL both shorter and longer than 18 carbons. The proteoliposomes made of short ACL lipids display structural heterogeneity revealing two quenched conformations of LHCII, each having characteristic 77K fluorescence spectra. One conformation spectrally resembles isolated LHCII aggregates, whilst the other resembles LHCII immobilized in polyacrylamide gels. Overall, the decrease in the ACL appears to produce quenched conformations of LHCII, which renders plausible the idea that the trigger of qE is the hydrophobic mismatch.

The Influence of Aerated Irrigation on the Evolution of Dissolved Organic Matter Based on Three-Dimensional Fluorescence Spectrum

In order to unravel the effect of aerated irrigation on soil dissolved organic matter (DOM) fluorescence characteristics, and humification degree, a randomized block experiment was conducted with three factors and a two-level design, i.e., two irrigation rates (0.6 and 1.0 times of crop evaporation pan coefficient, W1 and W2), two nitrogen application rates (225 and 300 kg hm−2, N1 and N2), and two aeration rates (15% and 0% in control treatment, A1 and A0). Fluorescence regional integration (FRI) and correlation analysis methods were used to investigate the evolution characteristics of the soil DOM fluorescence spectrum. Under aerated and conventional subsurface irrigation, soil DOM components were dominated by humic acid-like substances, fulvic acid-like substances, tryptophan-like proteins, and supplemented by tyrosine-like proteins and dissolved microbial metabolites. Soil aeration could promote the consumption of soil DOM components under low irrigation rates and accelerate the consumption of soil DOM components under high irrigation rates. The humification index of AI treatments varied from 8.47 to 9.94 during the maturity growth stage of pepper, averagely increased by 31.59% compared with the non-aeration treatment. To sum up, aerated irrigation can promote the depletion of small molecular proteins and accelerate nutrient turnover and the accumulation of big molecular proteins.

Breakdown Spectroscopy Induced by Nonlinear Interactions of Femtosecond Laser Filaments and Multidimensional Plasma Gratings

Breakdown spectroscopy is a valuable tool for determining elements in solids, liquids, and gases. All materials in the breakdown region can be ionized and dissociated into highly excited fragments and emit characteristic fluorescence spectra. In this sense, the elemental composition of materials can be evaluated by detecting the fluorescence spectrum. This paper reviews the recent developments in laser-induced breakdown spectroscopy. The traditional laser-induced breakdown spectroscopy, filament-induced breakdown spectroscopy, plasma grating, and multidimensional plasma grating-induced breakdown spectroscopy are introduced. There are also some proposals for applications of plasma gratings, such as laser ablation, laser deposition, and laser catalysis of chemical reactions in conjunction with research on the properties of plasma gratings.

Enone as TFO Linker: Synthesis and Parallel DNA Triplex Stability Evaluation

AbstractTwo new intercalated nucleic acid monomers, X and Y, possessing enone as linker have been synthesized. The monomers were incorporated into 14‐mer polypyrimidine strand to act as triplex‐forming oligonucleotide (TFO). The thermal stabilities of the formed parallel triplexes, parallel and antiparallel duplexes were evaluated to show high stability of its parallel triplexes at pH 5.0 and pH 7.2, while limited stability at pH 6.0 compared to unmodified triplex. The architectures of enone linker are shown to disturb the planarity of its parallel and antiparallel duplexes and consequently the π‐π stacking ability with the neighboring nucleobases. The data was confirmed by molecular dynamics simulation and binding energy calculations. Characteristic fluorescence spectra were also investigated to show the ability of X and Y containing TFO to discriminate parallel triplex from parallel and antiparallel duplex.

In Situ Downhole Fluid Analysis Systems Using LED, Laser-Induced Fluorescence, and Uranine-Traced Drilling Water.

The paper discusses a novel three-channel method to distinguish the formation oils, water, and uranine-based drilling mud and to monitor the clean-up process in the downhole fluid analysis systems. The proposed method is based on the study of the fluorescence spectra of the formation fluid or drilling mud samples. The experiment for different excitation sources (365 nm, 395 nm LEDs, and 405 nm, 460 nm laser sources) was carried out; the spectra were recorded with a VISION2GO VIS spectrometer. The characteristic features in fluorescence spectra of the crude oil sample and various concentrations of the uranine solution in pH-neutral water (5 mg/l, 10 mg/l, 25 mg/l, 50 mg/l, 100 mg/l) were observed. The sufficient unambiguous criterion for differentiating the type of fluid and clean-up process analysis is presented.

A synchronous spectrofluorometric technique for simultaneous detection of alfuzosin and tadalafil: applied to tablets and spiked biological samples.

A facile, accurate, eco-friendly and sensitive spectrofluorometric method was evolved to assay alfuzosin hydrochloride (AFH) and tadalafil (TDF) in different matrices. Such a co-administered combination is clinically used for the treatment of lower urinary tract symptoms. Both compounds are characterized by their native fluorescence spectra upon excitation at specific wavelengths. Their characteristic fluorescence spectra were used for sensitive assay of the studied analytes in tablets and human biological samples. The assay principle is based on first-order synchronous spectrofluorometric scan using Δλ = 60 nm in which AFH peaks were recorded at 366 nm. Meanwhile, TDF measurements were recorded at 293 nm in the same scans without overlap with AFH spectra. Recent analytical chemistry trends were implemented to lessen occupational and environmental perils, using ethanol as a diluting solvent for method optimization and application. Linearity ranges were 5.0–90.0 and 10.0–100.0 ng ml−1 for AFH and TDF, respectively in their raw materials with average % recoveries of 100.44% and 99.73% in raw materials, 100.15% and 100.20% in spiked plasma, and 97.14% and 99.99% in spiked urine. The proposed method was successfully applied to Prostetrol and Starkoprex commercial tablets with no interference with common tablet additives.

Facile and Selective Determination of Total Phthalic Acid Esters Level in Soft Drinks by Molecular Fluorescence Based on Petroleum Ether Microextraction and Selective Derivation by H2SO4.

Determining the level of phthalic acid esters (PAEs) in packaged carbonated beverages is a current need to ensure food safety. High-selectivity and -accuracy identification of individual PAEs can be achieved by chromatographic and mass spectrometric (MS) techniques. However, these methods are slow; involve complicated, expensive instruments in professional laboratories; and consume a large amount of organic solvents. As such, a food analysis method is needed to conveniently and rapidly evaluate multiple contaminants on site. In this study, with the assistance of ultrasound, we quickly determined the total PAEs in soft drinks using 1.5 mL of petroleum ether in one step. Then, we determined the characteristic molecular fluorescence spectrum of all PAEs in samples (excitation (Ex)/emission (Em) at 218/351 nm) using selectively concentrated sulfuric acid derivatization. The relative standard deviations of the fluorescent intensities of mixed solutions with five different PAEs were lower than 7.1% at three concentration levels. The limit of detection of the proposed method is 0.10 μmol L−1, which matches that of some of the chromatographic methods, but the proposed method uses less organic solvent and cheaper instruments. These microextraction devices and the fluorescence spectrometer are portable and provide an instant result, which shows promise for the evaluation of the total level of PAEs in beverages on site. The proposed method successfully detected the total level of PAEs in 38 kinds of soft drink samples from local supermarkets, indicating its potential for applications in the packaged beverage industry.

Synthesis of Topped ZnSeO4 QDs and their Evaluation as Chemical Nanosensors for Anthracene, Benzo (A) Pyrene, Pyrene and Pyridine

Synthesis and characterization of hexamine capped ZnSeO4 QDs (ZnSeO4-Hex) by heating up method (HU) was achieved. These, of two crystallite sizes, denoted QDsS1 and QDsS2; with crystallite diameters of 8.6 nm and 14.0 nm respectively. X-ray diffraction (XRD) pattern bared hexagonal close packed (hcp) crystal structure. Band gap for QDsS1 was 5.85 eV and for QDsS2 3.8 to 4.3 eV. Hexamine (C6H10N4) cap on ZnSeO4 QDs was elucidated by Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography-Mass Spectroscopy (GC-MS) results. Transmission Electron Microscopy (TEM) images revealed polycrystallites of different orientation, showing crystal grains separated by tilted grain boundary folds. These QDs were tested as optical chemical nano-sensors for carcinogenic organic pollutants: Anthracene (ANTH), Benzo (a) pyrene (BaP), pyrene (PRN) and pyridine (py). Results revealed that, when the organic pollutants interacted with the QDs, they caused characteristic changes in the way these nanoparticles interacted with characteristic fluorescence and absorbance spectrum

Relationship between non-point source pollution and fluorescence fingerprint of riverine dissolved organic matter is season dependent

The source identification of water pollution and quantification of pollution sources are vital for water environment management. Dissolved organic matter (DOM) affects the form, solubility, and toxicity of pollutants, so the migration and transformation of DOM are crucial for water quality assessment. Therefore, the aim of this study was to identify pollution sources and quantify their contribution in water environments using fluorescence fingerprint of DOM. The Danjiangkou Reservoir and its main tributaries were selected as the study area. The DOM fluorescence components of pollution source samples were analyzed and the quantitative relationship between DOM spectral indices and nitrate isotopes (δ15N-NO3− and δ18O-NO3−) was established. It was found that humic-like substances were mainly derived from non-point source (NPS) pollution and protein-like substances were from point source (PS) pollution. The fluorescence index (FI) of DOM was positively correlated with PS pollution and negatively correlated with NPS pollution. The quantitative relationship between three-dimensional (3D) fluorescence spectra characteristics of DOM and water quality indicators or NPS pollution was established, which realized the convenient quantitative evaluation of pollution load and pollution source contribution using DOM fluorescence spectra characteristics. The strength of the correlation between DOM fluorescence spectra characteristics and water quality indicators (or NPS pollution) was affected by seasonal rainfall due to changes in the contribution of PS and NPS pollution. This study provides a new approach for source identification of water pollution and quantification of pollution sources using 3D fluorescence fingerprint of DOM.

Mn-DOPPED ZnS QUANTUM DOTS AS SENSITIVE SENSOR FOR DETERMINATION OF CIPROFLOXACIN IN PHARMACEUTICAL AND BIOLOGICAL SAMPLES

A simple and fast spectrofluorimetric method for determination of ciprofloxacin based on its quenching effect on the fluorescence intensity of colloidal water ­soluble TGA ­caped, Mn doped ZnS quantum dots (QDs) has been described. The QDs having characteristic fluorescence spectra with maximum excitation at 315 nm followed by an emission peak at 632 nm were characterized using Energy Dispersive X-Ray and X-ray Diffraction techniques. The effect of various parameters such as concentration of QDs, time, pH, common excipients and metal ions on the quenching phenomenon was investigated. Fluorescence quenching was found to be maximum with 10 µg mL­-1 of QDs at pH 8 and fluorescence intensity was observed to be constant upto 45 min. The Stern­-Volmer calibration plot of F0/F as a function of ciprofloxacin concentration was found to be linear in the range of 0.5-10 µg mL­-1 with r² = 0.993. Under optimal experimental conditions the method was found to be interference free. The percent relative standard deviation of the proposed method calculated against method blank was found to be 1.10%. The limit of detection (LOD) and the limit of quantitation (LOQ) for Cf (signal to noise ratio 3:1 for LOD and 10:1 for LOQ) were calculated to be 0.15 and 0.50 μg mL-1 respectively. Average percent recoveries (±SD) obtained for spiked commercial formulations; ciprol and ciproquine, and serum and urine samples were found to be in the range of 92.2±1.8% to 99.5±1.5%, 90.5±1.2% to 96.7±1.4% and 94.0±1.2% to 98.5±1.4% respectively. The data evidently prove the potential of the proposed sensor QDs in biological analysis.

Fabrication of a green and sensitive quantum dots based fluorescent probe for determination of sparfloxacin in biological samples and drug formulations

A simple and fast spectrofluorimetric method for determination of sparfloxacin (SPAR) based on fluorescence quenching of colloidal water soluble TGA caped, Mn doped ZnS quantum dots (QDs) has been described. The QDs having characteristic fluorescence spectra with maximum emission at 632 nm (Excitation at 315 nm) were characterized using Energy Dispersive x-ray and x-ray Diffraction techniques. The effect of various parameters such as concentration of QDs, time, pH, common excipients and metal ions on the quenching phenomenon was investigated. Fluorescence quenching was found to be maximum with 10 μg ml−1 of QDs at pH 7 with fluorescence intensity remaining constant upto 60 min. The Stern-Volmer calibration plot of F0/F as a function of sparfloxacin concentration was found to be linear in the range of 0.2–2.2 μg ml−1 with r2 = 0.995. Under optimal experimental conditions the method was found to be interference free. The percent relative standard deviation of the proposed method calculated against method blank was found to be 1.67%. The limit of detection and the limit of quantitation for SPAR (n = 3 and 10 respectively) were calculated to be 0.07 and 0.21 μg ml−1 respectively. Average percent recoveries (±SD) obtained were found to be 89.16 ± 0.03 to 94.44 ± 0.15 μg ml−1 for serum and 85.00 ± 0.10 to 97.77 ± 0.37 μg ml−1 for urine samples. In case of commercial formulations sparaxcin and spar, the maximum % recovery was found to 89.33 ± 0.54% while in case of Quspar the % recovery obtained was less than 71.83 ± 0.14%. The proposed method was statistically compared with reported chromatographic method and no significant difference was observed.

Отличительные характеристики спектров эмиссии сырой нефти Апшеронского полуострова, зарегистрированные с помощью ЛИДАРА КА-14

KA-14 LIDAR, developed at National Aviation Academy of Azerbaijan with the financial support of State Oil Company of Azerbaijan Republic (SOCAR), have been used for detection of distinguishing characteristics of fluorescence spectra of crude oil spills on the surface of Caspian sea and the earth surface of Absheron peninsula. These spills may take place as a result of oil leakage from different Oil-Gas-Production Companies of Azerbaijann (there are totally 8 Oil-Gas-Production Companies belonging to AzNeft and 4 Joint Ventures). Emission spectra of crude oils at present work have been excited by 3d harmonic of Nd:YAG laser (l = 355 nm, d = 5 mm, f = 20 Hz; E = 60 mJ and t = 7 ns). Analysis of fluorescence emission spectra of crude oils taken from 12 Companies revealed distinguishing characteristics of these spectra, main of which included: shape of the spectra, spectral positions of maximum in emission spectra, existence of different fine structures (weak and strong “shoulders”) on short-, as well as long parts of spectra, intensity of emitted bands. Obtained results were useful for creation of data bank of fluorescence spectra of crude oil extracted on the earth of the Absheron peninsula of Azerbaijan as well as from water areas of the Caspian sea.

Effective sensitization of Eu3+ ions on Eu3+/Nd3+ co-doped multicomponent borosilicate glasses for visible and NIR luminescence applications

Eu3+/Nd3+ co-doped multicomponent borosilicate glasses (ND1E: 10BaO +10ZnF2+10K2O +20SiO2+(49-x) B2O3+1Nd2O3+xEu2O3) were prepared by conventional melting and rapid quench technique to evaluate the effect of Eu3+ ions in the Nd3+ doped glasses. Thermal stability, structural and spectroscopic characteristics of the ND1E glasses were investigated by using DSC, XRD, FTIR, Optical absorption, excitation and emission measurements. The Judd – Ofelt (JO) analysis is implemented to the absorption spectrum of the prepared glassy matrix in order to identify their potential applicability in lasing devices. Enhancement of 7F0 → 5L6 band (394 nm) with the increasing concentration of Eu3+ ion in the Nd3+ excitation spectra (λemi = 1060 nm) reveals the possibility of obtaining the characteristic fluorescence spectra of Nd3+ ion with the typical excitation wavelengths (Nd3+ = 584 nm and Eu3+ = 394 nm) of both rare earth ions and it is further verified from the emission spectrum. This interesting luminescence effect of showing excellent visible and NIR emission under 394 nm excitation mainly attributes the energy transfer mechanism between the RE3+ ions and the reason underlying this effect is discussed in detail with the help of partial energy level diagram. Energy transfer efficiency between the Eu3+ and Nd3+ ions were evaluated by using the radiative lifetimes of the prepared glasses. Also, a comparison of radiative properties and lasing characteristics of Eu3+/Nd3+ co-doped glasses with other Nd3+ glasses are reported. The emission intensities were characterized using CIE chromaticity diagram and the observed CIE coordinates shows a shift towards reddish – orange region with the increase in Eu3+ concentration. The quantum efficiency of the prepared glasses was determined experimentally. The obtained results suggest that the ND1E glassy system can be considered as a potential candidate for visible and NIR luminescence applications.

Characteristics of Fluorescence Spectra, UV Spectra, and Specific Growth Rates during the Outbreak of Toxic Microcystis Aeruginosa FACHB-905 and Non-Toxic FACHB-469 under Different Nutrient Conditions in a Eutrophic Microcosmic Simulation Device

Microcystis aeruginosa is the dominant alga forming cyanobacteria blooms, the growth of which is limited by available nutrients. Thus, it is necessary to study cyanobacteria blooms and explore the growth of Microcystis aeruginosa under different nutrient conditions. In this paper, we take Microcystis aeruginosa, including toxic Freshwater Algae Culture of Hydrobiology Collection (FACHB)-905 and non-toxic FACHB-469 strains, into account. The strains were cultured using a simulation device under different nutrient conditions. Ultraviolet spectra, three-dimensional fluorescence spectra, and kinetic parameter indicators of the two species are studied. Compared to FACHB-469, the results show that the specific growth rate of FACHB-905 is much higher, in particular, FACHB-905 is the dominant species under low nutrient conditions. Furthermore, the UV spectral characteristics indicate that the molecular weight of dissolved organic matter in the culture tank of toxic FACHB-905 is greater than that of FACHB-469. Additionally, the humification index of toxic FACHB-905 is slightly higher as well, which suggests that it is more stable in the presence of dissolved organic matter during blooms. Therefore, the toxic Microcystis strain is more likely to become the dominant species in water blooms under lower eutrophic conditions and water blooms formed by the toxic Microcystis strain may be more difficult to recover from.

Dermatofluoroscopy Is Also for Redheads a Sensitive Method of Early Melanoma Detection

Background: Caucasians with red hair and fair skin have a remarkably increased risk of malignant melanoma compared to non-redhead Caucasians. Objectives: With the aim of a reliable melanoma diagnosis in redheads, the application of dermatofluoroscopy was analyzed in 16 patients with red hair. Most of them had been included in a clinical dermatofluoroscopy study for patients with the suspicion of melanoma. We examined whether the 25 lesions of the redheads showed the same characteristic melanin fluorescence spectra for dysplastic nevi and melanomas as those of non-redhead Caucasians or whether there was a different fluorescence pattern. This is important in view of the known significantly altered ratio of eumelanin to pheomelanin in the skin of redheads. Methods: More than 8,000 spatially resolved fluorescence spectra of 25 pigmented lesions were measured and analysed. The spectra were excited by the stepwise absorption of two 800-nm photons (principle of dermatofluoroscopy). Furthermore, the fluorescence spectra of eumelanin and pheomelanin in hair samples were determined in the same way. Results: The evaluation revealed that the melanin fluorescence spectra of dysplastic nevi and melanomas of redheads have the same spectral characteristics as those of non-redhead Caucasians. An accompanying result is that dermatofluoroscopy shows identical fluorescence spectra for eumelanin and pheomelanin. Conclusions: Dermatofluoroscopy proves to be a reliable diagnostic method also for redheads. Our results also explain our recent finding that there is a uniform fluorescence spectroscopic fingerprint for melanomas of all subtypes, which is of particular interest for hypomelanotic and apparently amelanotic melanomas containing pheomelanin.

Characteristics of three-dimensional fluorescence spectra and its correlation with water quality of surface water during dry and wet seasons in Lake Ebinur Watershed, Xinjiang

以艾比湖流域主要入湖河流为研究对象，在5月（丰水期）和8月（枯水期）分别沿博尔塔拉河（博河）和精河进行采样，采用平行因子模型（PARAFAC）和三维荧光区域积分法对水体三维荧光特性进行研究并对其与水质的关系在枯、丰水期下的变化进行探讨.结果表明①河流DOM在枯水期与丰水期都含有C1（240、425 nm） UVC类腐殖质，C2（225、290 nm）紫外区内络氨酸类有机物，C3（230/280、330 nm）蛋白类有机物，C4（265、260 nm）腐殖质类共4种组分.通过对水体三维荧光进行区域积分可以看出DOM荧光成分的占比在不同时期的变化.博河在枯水期时EEM光谱中的区域Ⅲ富里酸含量低于丰水期，枯水期时区域Ⅱ芳香类蛋白质、区域Ⅳ可溶性微生物代谢物以及区域Ⅴ类腐殖质酸高于丰水期；对于精河来说，区域Ⅱ芳香类蛋白质和区域Ⅳ可溶性微生物代谢物在枯水期的含量高于丰水期，区域Ⅲ富里酸和区域Ⅴ类腐殖质酸的含量枯水期低于丰水期，这表明水体腐质化程度较高.②本研究选取了一些常规的荧光指数来描述枯、丰水期水体的荧光指数特性.经研究发现，精河的荧光指数、自生源指数和腐殖化指数在不同时期的变化幅度较小，而博河的变化幅度较大.③将荧光指数与水质参数进行相关性分析并建模，结果表明枯水期自生源指数（BIX）与化学需氧量呈显著正相关，相关系数R=0.688；丰水期时BIX与铵态氮浓度呈显著负相关，相关系数R=-0.493.通过对比分析艾比湖主要入湖河流的三维荧光光谱特性与水质在枯、丰水期时的关系进一步表明水体中DOM的特性以及在枯、丰水期下的差异，为艾比湖流域的治理改善提供一定的理论支持和参考依据.;This study takes the main lakes in Lake Ebinur Watershed as the research object, and samples along the Bortala River and Jing River in May (wet season) and August (dry season). The PARAFAC analysis method and the three-dimensional fluorescence region integration method is used to study the three-dimensional fluorescence characteristics of water and its seasonal variation with water quality. The results show that:1)In both dry and wet seasons, river DOM contains C1 (240, 425 nm) and C4 (265, 260 nm) kind of humus, C2 (225, 290 nm) uranium-like organic matter compounds. It found that fulvic acid is lower, while the aromatic protein, soluble microbial and humic acid were highest in dry season than wet season in Bortala River. The concentration of the aromatic protein and soluble microbial in dry season was higher than in wet season, and the fulvic acid and humic acid in dry season was lower than in the wet season in Jing River, based on fluorescence regional integral (FRI) analysis and the regional standards related to water quality and fluorescence. This indicates that the degree of decomposition in water is relatively high; 2)In this study, some conventional fluorescence indexes were selected to describe the fluorescence index characteristics of water in wet and dry season. It found that the three indexes (FI, BIX, HIX) of the water quality of Jing River and Bortala River in dry and wet seasons showed slight changes, comparing to larger changes in the Bortala River. In general, the change of water quality of Jing River and Bortala River in dry and wet seasons is mainly influenced by microbial activities and human activities; 3) In terms of the correlation coefficients of water quality parameters and fluorescence indexes in different seasons, the results showed that the relationship between BIX and COD concentration was best and a significant positive correlation in dry season(R=0.688, P<0.01). Secondly, there is a significant negative correlation between BIX and ammonium nitrogen concentration in wet season (R=-0.493, P<0.05). The study provides theoretical support and reference basis for the improvement of the governance of Lake Ebinur Watershed, which further proved that exogenous characteristics and the differences in different periods of DOM sources in the water.

Laser-induced fluorescence diagnosis of stomach tumor

The purpose of this study is to demonstrate the capabilities of laser spectral and video fluorescence diagnosis used for stomach tumors using 5-ALA photosensitizer. The spectroscopic method is presented with an example of a characteristic fluorescence spectrum from stomach with 5-ALA and quantitative statistics. The laser excitation wavelength was 632.8nm. The analysis of the video system is presented with clinical statistics. The penetration depth of 3-4mm of the He-Ne laser during the spectroscopic study allowed for scanning the mucous and submucous layers of the stomach and for detecting tumorous growths in these layers. Registration of fluorescence using the spectral system enabled surgeons to conduct express estimation of dubious stomach tissues, to make biopsy from doubtful areas to reveal precancer and early cancer states. The video fluorescence analysis with the application of 5-ALA-induced PPIX may be recommended for the use as an express method of diagnosis including early diagnosis of malignant stomach diseases as well as for intraoperative assessment of tumor extension and detection of canceromatous foci during laparoscopy. The optimal time interval for the diagnosis (regardless of the nature of the study - endoscopic, laparoscopic, or intraoperative) is 2-4h from the administration of photosensitizer. The optimal dose of the photosensitizer is 20mg per 1kg of the body weight.