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Ocular burns are ophthalmological emergencies, owing to their potentially serious visual complications. Prompt recognition, irrigation and comprehensive examination including fluorescein staining is recommended to optimise outcomes. Burns standards recommend ophthalmological services be available in a 'timely' manner. This paper is a retrospective review of facial burn admissions between November 2017 and November 2018 at the Queen Elizabeth Hospital Birmingham (QEHB), a regional burns centre in the United Kingdom. This study aims to assess referral rates to ophthalmology, timeliness of review and the proportion of patients reviewed within a 24h window. From the data available we also aim to determine the frequency of fluorescein examination. Of 88 patients admitted with facial burns, data was available for 80 patients. The majority (n=77, 87.6%) suffered thermal burns. Twenty-two (27.5%) patients were referred to ophthalmology, and 18 (22.5%) had a documented review. Mean time from admission to review was 45.0h, with 10 (52.6%) patients being seen within 24h. Of 80 patients, 50 (62.5%) patients had no documented fluorescein examination. Further prospective studies are necessary to inform clinical guidelines and optimise management of facial burns. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fluorophotometry has great advantages in sensing low concentration of ferric ions. • Visual detection platform is achieved via a portable colorimeter or smartphone. • The optical and visual multi-mode Fe3+ probes perform well in real water samples. Abnormal iron ions levels may lead to some diseases and serious environmental pollution. Herein, optical and visual detection strategies of Fe3+ in water based on co-doped carbon dots (CDs) were established in the present study. Firstly, a one-pot synthetic strategy for the preparation of the N, S, B co-doped CDs with a home microwave oven was developed. Secondly, the optical properties, chemical structures, and morphology of CDs were further characterized by fluorescence spectroscopy, Uv–vis absorption spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscope. Finally, the results indicated that the fluorescence of the co-doped CDs was quenched by ferric ions via the static mechanism and the aggregation of CDs, accompanied by the increased red color. The multi-mode sensing strategies of Fe3+ with fluorescence photometer, UV–visible spectrophotometer, portable colorimeter and smartphone had the advantages of good selectivity, excellent stability and high sensitivity. Fluorophotometry based on co-doped CDs was a powerful probe platform for measuring lower concentrations of Fe3+ due to its higher sensitivity, better linear relationship, lower limit of detection (0.27 μM) and limit of quantitation (0.91 μM). In addition, the visual detection methods with a portable colorimeter and smartphone had been proven to be very suitable for rapid and simple sensing of higher concentrations of Fe3+. Moreover, the co-doped CDs utilized for Fe3+ probes in tap water and boiler water obtained satisfactory results. Consequently, the efficient, versatile optical and visual multi-mode sensing platform could be extended to apply such a visual analysis of ferric ions in the biological, chemical and other fields. [ABSTRACT FROM AUTHOR]

Abstract Facing the problem of a growing number of analyses, the need for using simple equipment appears. Smartphone-based optical detection is one of the most widely applied ideas nowadays. A personal device such as a smartphone equipped with a camera is affordable even in the source-limited places. After a simple modification, providing the light source of both defined properties and orientation, a smartphone may become an efficient analytical device. In this work we present a uniform methodology of such a modification, offering a complete hand-held device for fluorometric measurements. Inducing the fluorescence of the tested analytes was done by ordinary light-emitting diodes, and phone camera was used as a detector. Then the obtained images were analyzed using the RGB colour model to get proper calibration curves. The demonstration of the system performing with the use of fluorescein preceded the examples of determination of quinine, rhodamine B, riboflavin and calcein in real-life circumstances. Example determinations of the calcium ions in mineral water and riboflavin in alcoholic beverages are provided. The results obtained with the designed device are fully comparable to the ones obtained with the conventional fluorometric equipment. The presented systems allow determination of all the investigated analytes with satisfactory detection limits, in some cases down to ppb levels. Thanks to the use of LEDs, the system could be adapted for both measuring and inducing fluorescence in different analytes, characterized by various excitation wavelengths. Graphical abstract fx1 Highlights • Portable smartphone system for determination of the fluorogenic substances is demonstrated. • The analytical performance of the set up was compared to the conventional fluorimeter equipment. • Data were analyzed using the RGB model, and the results were explained according to the CMOS characteristic and sensitivity. • The practical usefulness of the system in different scenarios using real samples was confirmed. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this pilot study was to evaluate tear inflow in a scleral lens system using fluorophotometry, and indirectly assess the exchange of the tear reservoir in habitual scleral lens wearers with the presence or absence of midday fogging (MDF).Methods: Habitual scleral lens wearers (n=23) and normal scleral lens neophytes (n=10) were recruited. Of the 23 habitual wearers, 11 of them experienced MDF and 12 did not have a diagnosis of MDF. Contact lens-fitting characteristics were evaluated using ocular coherence tomograpy (OCT) and biomicroscopy. High molecular weight fluorescein (FITC) Dextran was instilled into the tear reservoir beneath the scleral lens, and the tear fluid fluorescein concentration was measured using the Fluorotron fluorophotometer. Calculated fluorescein concentrations were plotted over time to measure the fluorescein decay rate of the tear fluid beneath the scleral lens, which was used to calculate the tear exchange rate.Results: There was no significant difference in tear inflow between the MDF group (mean: 0.111%) and the non-MDF group (mean: 0.417%), and there was a high amount of variability seen in the rates (p = 0.26). In addition, there was no significance between the tear reservoir thickness in the MDF (283um) and non-MDF (326um) groups (p = 0.53).Conclusions: The relationship between the amount of tear exchange during scleral lens wear and the incidence of MDF was not significant. Additional studies are needed to further examine the role of tear exchange in MDF and address the causes of variability to improve measurement techniques with fluorophotometry in the scleral lens system. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the patient-administered Optrex™ Dry Eye Blink Test against established clinical criteria for the diagnosis of dry eye disease (DED) and to evaluate its benefit in enhancing screening for DED.Methods: Eighty-seven participants aged 38 ± 17 years, (44 female) were screened for DED using the Tear Film and Ocular Surface Society Dry Eye Workshop II (TFOS DEWS II) diagnostic criteria. In addition to symptoms screening with the Ocular Surface Disease Index questionnaire (≥13 cut-off score for DED), these criteria required a sign of loss of homeostasis of the tear film in the form of a non-invasive tear breakup time (NIBUT) <10 s (Oculus Keratograph; K5M), an osmolarity reading ≥308 mOsm/L or an interocular difference in osmolarity of >8 (Tearlab), or ocular surface staining (>5 fluorescein corneal spots, >9 lissamine green spots or lid wiper staining [≥2 mm length & ≥25% width]) to confirm a diagnosis of DED. The self-administered Blink Test, which requires the participant to observe an image on a computer screen and report the length of time (in seconds) that they can refrain from blinking without discomfort, was repeated three times.Results: Using a cut-off time of 10 s, the Blink Test demonstrated sensitivity of 66%, specificity of 88%, and an area under the curve of 0.77 (p < 0.001), in predicting a diagnosis of DED according to the TFOS DEWS II criteria. The correlation between the Blink Test and NIBUT was r = 0.47 (p < 0.001). When combined with the screening questionnaire, the sensitivity and specificity of the Blink Test increased to 71% and 90%, respectively.Conclusion: The Blink Test offers health professionals without advanced instrumentation, as well as patients, themselves, a rapid method of identifying possible DED. [ABSTRACT FROM AUTHOR]

A highly fluorescent carbon dots were prepared by a facile one-pot hydrothermal method using degrease cotton (human waste) as the carbon source. The structure and morphology of prepared C-dots were characterized by fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The as-prepared C-dots exhibit excellent emission property, high stability and have a narrow size distribution of 2–4 nm in diameter. Moreover, it is attractive that C-dots can be used as an effective fluorescent probe for the detection of chromium ions with good selectivity and sensitivity in an aqueous solution. The quenching phenomenon was observed after the C-dots interacted with the metal ions; and the results showed that the optimum conditions for its interaction with chromium ions were: 4.0×10 −5 g/mL of concentration of C-dots, pH=6.5 of buffer solution, and 20 min of time. Based on the optimum conditions, a new sensitive method detecting chromium ions was established. The method has been successfully applied to detect chromium ions in water and soil samples with satisfactory results. [ABSTRACT FROM AUTHOR]

1-(2,5-Dimethylfuran-3-yl)-3-(2,4,5-trimethoxyphenyl)prop-2-en-1-one (DFTP) was prepared by the reaction of 2,4,5-trimethoxybenzaldehyde and 3-acetyl-2,5-dimethyfuran. Various spectroscopic techniques including EI-MS, FT-IR, 1 H-NMR, 13 C-NMR spectral and elemental analysis were applied to confirm the structure of DFTP. The effect of different solvents with DFTP has been observed by the electronic absorption and emission spectroscopy. The resulting red shift obtained in the emission spectrum of DFTP as solvent polarity increases, represents a large change in dipole moment of DFTP molecule upon excitation due to intramolecular charge transfer in excited DFTP. Excited state intermolecular hydrogen bonding affects the energy of emission spectrum and fluorescence quantum yield of DFTP molecule. The DFTP dye undergoes solubilization in different micelles and may be used as a probe to determine the critical micelle concentration (CMC) of SDS and CTAB. The photoreactivity and net photochemical quantum yield (ϕ c ) of DFTP are determined in different solvents such as CHCl 3 , CH 2 Cl 2 , CCl 4 , and DMSO. The DFTP dye is relatively photostable in DMSO and displays photodecomposition in chloromethane solvents. [ABSTRACT FROM AUTHOR]

A new and facile method for the determination of critical micelle concentration (CMC) of ionic and non-ionic surfactants is proposed in this article. Carbon dots exhibited substantial fluorescence and therefore enhanced the sensitivity of this evaluation. Understanding the formation of surfactant micelles is vital for the applications of biomedicine such as drug fabrication and smart molecular vehicles in delivering therapeutic dosage to various molecular sites. The fluorescence property of carbon dots was utilized for the first time to estimate the critical micelle concentration of surfactants. The central concept of the approach is based on the Stokes shift determination of a system composed of constant amount of carbon dots with varying concentrations of ionic and non-ionic surfactants. The synthesized carbon dots were characterized by FTIR, TEM, XRD, Raman, UV, and fluorescence spectroscope. The carbon dots were excited at 280 nm so as to obtain maximum emission for the Stokes shift measurement. The CMC value of cetyltrimethyl ammonium bromide (CTAB), sodium dodecyl sulfate (SDS), Triton X-100, dodecyldimethyl(3-sulfopropyl)ammonium hydroxide (SB-12) evaluated by this approach was found to be 0.98, 7.3, 0.19, and 3.5 mM, respectively. The signals of spectra were assigned and explained in terms of both electron transitions between specific molecular orbital and the interaction with solvent. [ABSTRACT FROM AUTHOR]

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The specific and sensitive detection of peroxynitrite (ONOO – /ONOOH) in biological systems is a great challenge due to its high reactivity towards several biomolecules. Herein, we validated the advantages of using fluorescein-boronate (Fl-B) as a highly sensitive fluorescent probe for the direct detection of peroxynitrite under biologically-relevant conditions in two different cell models. The synthesis of Fl-B was achieved by a two-step conversion synthetic route with high purity (> 99 %) and overall yield (∼ 42%). Reactivity analysis of Fl-B with relevant biological oxidants were performed. The rate constant for the reaction of peroxynitrite with Fl-Bwas 1.7 x 10 6 M -1 s -1 , a million times faster than the rate constant measured for H 2 O 2 (k = 1.7 M -1 s -1 ) and 2,700 faster than HOCl (6.2 x 10 2 M -1 s -1 ) at 37° C and pH 7.4. The reaction of Fl-B with peroxynitrite was significant even in the presence of physiological concentrations of CO 2 , a well-known peroxynitrite reactant. Experimental and simulated kinetic analyses confirm that the main oxidation process of Fl-B takes place with peroxynitrite itself via a direct bimolecular reaction and not with peroxynitrite-derived radicals. Fl-B was successfully applied for the detection of endogenously- generated peroxynitrite by endothelial cells and in macrophage-phagocyted parasites. The generated data allowed estimating the actual intracellular flux of peroxynitrite, e.g., ionomycin-stimulated endothelial cells generated peroxynitrite at a rate of ∼ 0.1 μM s -1 , while immunostimulated macrophages do so in the order of ∼ 1 μM s -1 inside T. cruzi -infected phagosomes. Cellular peroxynitrite detection was achieved by conventional laboratory fluorescence-based methods including flow cytometry and epi-fluorescence microscopy. Fl-B was shown to be more sensitive than the coumarin boronate due to a higher molar absorption coefficient and quantum yield. Overall, our results show that Fl-B is a kinetically selective and highly sensitive probe for the direct detection of cell-derived peroxynitrite. Moreover, the data allowed to tailor boronate-derivatives targeted to identify subcellular sites and rates of peroxynitrite generation; indeed, ongoing work is focused on the generation and characterization of new organelle-targeted boronate-based probes. [ABSTRACT FROM AUTHOR]