Dry eye disease in head and neck cancer patients undergoing radiotherapy.

Purpose: To study the incidence of dry eye disease (DED) in head and neck cancer (HNC) patients undergoing external beam radiotherapy (EBRT), to find a correlation between tumor location and total radiation dose with DED, and to report various radiotherapy (RT) induced acute toxic effects on ocular and adnexal structures. Methods: A prospective cohort study was conducted at a tertiary eye-care center on 90 patients of HNC undergoing EBRT from March 2021 to May 2022. All underwent a thorough clinical history and complete ophthalmological examination including an ocular surface disease index (OSDI) questionnaire, visual acuity, anterior segment, angle and posterior segment examination, dry eye workup including the Schirmer test, tear meniscus height, tear break-up time, corneal fluorescein staining and grading, and meibography by auto-refractometer and its scoring at each visit. Patients were evaluated before the start of RT and then at 1 week, 4 weeks, and 12 weeks post-RT. Radiation records of all patients were noted. Data were analyzed using percentage and Microsoft Excel. Results: Of the 90 patients, 66 were male and 24 female (M: F ratio of 2.75) with a median age of 52.5 years (range 24 to 80 years). The most common HNC was the carcinoma oral cavity and lip. Most patients received a total radiation dose between 46 to 55 Gy. DED developed in 48 (53.3%) patients. The incidence of DED increased with the increase in total radiation dose (r = 0.987). DED was also found to be correlated with tumor location (r = 0.983). Conclusion: The incidence of DED positively correlated with the total radiation dose and tumor location.

Oral pilocarpine for the treatment of dry eye in patients with Sjögren's syndrome.

PURPOSE: To evaluate the efficacy of oral pilocarpine (20 mg daily) for the treatment of dry eye in patients with Sjogren's Syndrome. The frequency of side effects reported during the treatment was also investigated. METHODS: In this placebo-controlled crossover study, 32 patients with Sjögren's syndrome were enrolled to receive either oral pilocarpine or placebo for 10 weeks. Following a 2-week washout period, the treatment was inverted for each patient for the same duration. Assessments included the quality of life National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25), dry eye specific questionnaire Ocular Surface Disease Index, non-invasive breakup time, invasive breakup time with fluorescein, corneal and conjunctival staining patterns with the use of fluorescein and rose bengal staining, Schirmer's test, and tear ferning test. RESULTS: According to the NEI-VFQ-25, there was statistically significant improvement in the quality of life following oral pilocarpine. Similar results were observed for ocular discomfort, as determined by the Ocular Surface Disease Index. All clinical tests showed favorable and statistically significant results following the use of oral pilocarpine. Regarding the analysis of tear samples, there was an improvement in the quality of tear film. This was evidenced by the modification of the patterns observed in the tear ferning test. Side effects were reported by 96.8% and 56.2% of the patients who received pilocarpine and placebo, respectively. Sweating was the most frequently reported side effect (67.74% versus 11.11%, respectively). CONCLUSIONS: Although the treatment was associated with a high frequency of side effects, oral pilocarpine (20 mg daily) was able to relieve discomfort related to dry eyes in patients with Sjögren's syndrome and induce favorable structural changes in the tear film.

Fluorescent markers rhodamine B and uranine for Anopheles gambiae adults and matings.

BACKGROUND: Marking mosquitoes is vital for mark-release-recapture and many laboratory studies, but their small size precludes the use of methods that are available for larger animals such as unique identifier tags and radio devices. Fluorescent dust is the most commonly used method to distinguish released individuals from the wild population. Numerous colours and combinations can be used, however, dust sometimes affects longevity and behaviour so alternatives that do not have these effects would contribute substantially. Rhodamine B has previously been demonstrated to be useful for marking adult Aedes aegypti males when added to the sugar meal. Unlike dust, this also marked the seminal fluid making it possible to detect matings by marked males in the spermatheca of females. Here, marking of Anopheles gambiae sensu stricto with rhodamine B and uranine was performed to estimate their potential contribution. METHODS: Two fluorescent markers, rhodamine B and uranine, were dissolved in sugar water and fed to adult An. gambiae. Concentrations that are useful for marking individuals and seminal fluid were determined. The effects on adult longevity, the durability of the marking and detection of the marker in mated females was determined. Male mating competitiveness was also evaluated. RESULTS: Rhodamine B marking in adults is detectable for at least 3 weeks, however uranine marking declines with time and at low doses can be confused with auto-fluorescence. Both can be used for marking seminal fluid which can be detected in females mated by marked males, but, again, at low concentrations uranine-marking is more easily confused with the natural fluorescence of seminal fluid. Neither dye affected mating competitiveness. CONCLUSIONS: Both markers tested could be useful for field and laboratory studies. Their use has substantial potential to contribute to a greater understanding of the bio-ecology of this important malaria vector. Rhodamine B has the advantage that it appears to be permanent and is less easily confused with auto-fluorescence. The primary limitation of both methods is that sugar feeding is necessary for marking and adults must be held for at least 2 nights to ensure all individuals are marked whereas dusts provide immediate and thorough marking.

Long duration stabilization of porous silicon membranes in physiological media: Application for implantable reactors.

The natural biodegradabilty of porous silicon (pSi) in physiological media limits its wider usage for implantable systems. We report the stabilization of porous silicon (pSi) membranes by chemical surface oxidation using RCA1 and RCA2 protocols, which was followed by a PEGylation process using a silane-PEG. These surface modifications stabilized the pSi to allow a long period of immersion in PBS, while leaving the pSi surface sufficiently hydrophilic for good filtration and diffusion of several biomolecules of different sizes without any blockage of the pSi structure. The pore sizes of the pSi membranes were between 5 and 20 nm, with the membrane thickness around 70 µm. The diffusion coefficient for fluorescein through the membrane was 2 × 10-10 cm2 s-1, and for glucose was 2.2 × 10-9 cm2 s-1. The pSi membrane maintained that level of glucose diffusion for one month of immersion in PBS. After 2 months immersion in PBS the pSi membrane continued to operate, but with a reduced glucose diffusion coefficient. The chemical stabilization of pSi membranes provided almost 1 week stable and functional biomolecule transport in blood plasma and opens the possibility for its short-term implantation as a diffusion membrane in biocompatible systems.

Hybrids of a 9-anthracenyl moiety and fluorescein as chemodosimeters for the detection of singlet oxygen in live cells.

Singlet oxygen (1O2) plays an important role in human innate immune response, plant physiology and anticancer photodynamic therapy (PDT). Therefore, its monitoring by convenient and sensitive methods (e.g. by detecting a fluorescence signal) by using non-toxic reagents would be advantageous. Known fluorogenic 1O2-chemodosimeters can potentially consume reducing agents in cells leading to the generation of toxic side products that limit their applications. In this paper we report on a series of 9-anthracenyl-fluorescein hybrids, which do not require any reducing agents for their reaction with 1O2. The selected compound 8d at a very low concentration of 100 nM is able to detect 1O2 in live human promyelocytic leukemia HL-60 cells with over 35-fold fluorescence signal enhancement within only 20 min assay time. This chemodosimeter is not toxic to HL-60 cells at concentrations ≤1 µM (higher concentrations were not tested) even at long incubation times ≤48 h.

Hydrological tracers, the herbicide metazachlor and its transformation products in a retention pond during transient flow conditions.

Since decades, surface water bodies have been exposed to pesticides from agriculture. In many places, retention systems are regarded as an important mitigation strategy to lower pesticide pollution. Hence, the processes governing the transport of pesticides in and through a retention system have to be understood to achieve sufficient pesticide attenuation. In this study, the temporal dynamics of metazachlor and its transformation products metazachlor-oxalic acid (OA) and -sulphonic acid (ESA) were observed in an agricultural retention pond and hydrologic tracers helped to understand system-inherent processes. Pesticide measurements were carried out for 80 days after their application during transient flow conditions. During a short-term (3 days) experiment, the tracers bromide, uranine and sulphorhodamine B were used to determine hydraulic conditions, residence times and sorption potential. A long-term experiment with sodium naphthionate (2 months) and isotopes (12 months) provided information about inputs via interflow and surface-groundwater interactions. During transient conditions, high concentration pulses of up to 35 µg L-1 metazachlor, 14.7 µg L-1 OA and 22.5 µg L-1 ESA were quantified that enduringly raised solute concentrations in the pond. Mean residence time in the system accounted for approximately 4 h showing first tracer breakthrough after 5 min and last tracer concentrations 72 h after injection. While input via interflow was confirmed, no evidence for surface-groundwater interaction was found. Different tracers illustrated potentials for sorption and photolytic degradation inside the system. This study shows that high-resolution sampling is essential to obtain robust results about retention efficiency and that hydrological tracers may be used to determine the governing processes.

Environmental and Personal Protective Equipment Contamination during Simulated Healthcare Activities.

Providing care to patients with an infectious disease can result in the exposure of healthcare workers (HCWs) to pathogen-containing bodily fluids. We performed a series of experiments to characterize the magnitude of environmental contamination-in air, on surfaces and on participants-associated with seven common healthcare activities. The seven activities studied were bathing, central venous access, intravenous access, intubation, physical examination, suctioning and vital signs assessment. HCWs with experience in one or more activities were recruited to participate and performed one to two activities in the laboratory using task trainers that contained or were contaminated with fluorescein-containing simulated bodily fluid. Fluorescein was quantitatively measured in the air and on seven environmental surfaces. Fluorescein was quantitatively and qualitatively measured on the personal protective equipment (PPE) worn by participants. A total of 39 participants performed 74 experiments, involving 10-12 experimental trials for each healthcare activity. Healthcare activities resulted in diverse patterns and levels of contamination in the environment and on PPE that are consistent with the nature of the activity. Glove and gown contamination were ubiquitous, affirming the value of wearing these pieces of PPE to protect HCW's clothing and skin. Though intubation and suctioning are considered aerosol-generating procedures, fluorescein was detected less frequently in air and at lower levels on face shields and facemasks than other activities, which suggests that the definition of aerosol-generating procedure may need to be revised. Face shields may protect the face and facemask from splashes and sprays of bodily fluids and should be used for more healthcare activities.

A comparative study of contamination in three closed systems for the preparation of hazardous drugs through simulations with fluorescein / Estudio comparativo de contaminación de tres sistemas cerrados para la preparación de fármacos peligrosos mediante simulación con fluoresceína

Objective: The objective of this study was to compare the environmental contamination generated during the preparation of cytostatic agents using three different methods through simulations using fluorescein, and the time required for preparation of each method. Method: A comparative study of the processing of fluorescein mixtures using three types of closed systems was conducted at the centralized unit for hazardous drugs of the Pharmacy Department of a General Teaching Hospital. Environmental contamination was detected in critical points of connection, and in splashes produced at any other points. The main variable was qualitative detection of contamination through ultraviolet light when three methods were compared (method A: ChemoClave(R), method B: SmartSite(R)valve and Texium(R)connector, method C: PhaSealTMwith BD luer extension). A final number of 60 mixtures were prepared to detect differences of at least 5%. Results: Qualitative contamination at the critical points during preparation, was seen in groups A and B for every mixture that was processed. No contamination at all in critical points was seen in any of the mixtures prepared using PhaSealTM. Statistically significant differences were found between arms A and C (p < 0.001) and arms B and C (p < 0.001); no differences were found between arms A and B. Conclusions: The combination of PhaSealTMsystem in conjunction with the BD luer extension for administering hazardous drugs from a tree modality system has been shown to be the system with the lowest level of contamination during processing without increasing the time required for preparation of the mixture

Objetivo: El objetivo de este estudio fue comparar la contaminación ambiental generada durante la preparación de fluoresceína y el tiempo de preparación usando tres sistemas cerrados de transferencia diferentes. Método: Estudio comparativo de elaboración de mezclas de fluoresceína con tres tipos de sistemas cerrados en una unidad de mezclas peligrosas de un Servicio de Farmacia de un Hospital General Universitario. Se consideró contaminación ambiental la detectada en los puntos críticos de conexión y las salpicaduras generadas en cualquier otro punto distinto. La variable principal fue la detección cualitativa mediante luz ultravioleta de la contaminación generada cuando se comparan tres sistemas (sistema A: ChemoClave(R), sistema B: válvula SmartSite(R)y conector Texium(R), sistema C: PhaSealTMcon alargadera luer BD). Se prepararon 60 mezclas para poder detectar diferencias de al menos el 5%. Resultados: Se detectó contaminación en los puntos críticos durante la preparación en todas las mezclas de los grupos A y B. No se detectó contaminación en ninguna de las mezclas en las que se usó el sistema cerrado PhaSealTM. Se encontraron diferencias estadísticas entre los grupos A y C (p < 0,001) y entre los grupos B y C (p < 0,001); no se encontraron diferencias entre los grupos A y B. Conclusiones: La combinación del sistema PhaSealTMy la alargadera luer BD para administrar fármacos peligrosos en la modalidad de árbol ha mostrado ser el sistema con el menor nivel de contaminación durante la preparación, sin que esto se traduzca en aumento en el tiempo de elaboración

A comparative study of contamination in three closed systems for the preparation of hazardous drugs through simulations with fluorescein.

OBJECTIVE: The objective of this study was to compare the environmental contamination generated during the preparation of cytostatic  agents using three different methods through simulations using fluorescein, and  the time required for preparation of each method. METHOD: A comparative study of the processing of fluorescein mixtures using three types of closed systems was conducted at the centralized unit for  hazardous drugs of the Pharmacy Department of a General Teaching Hospital. Environmental contamination was detected in critical points of  connection, and in splashes produced at any other points. The main variable was  qualitative detection of contamination through ultraviolet light when three  methods were compared (method A: ChemoClave®, method B: SmartSite®  valve and Texium® connector, method C: PhaSealTM with BD luer extension). A  final number of 60 mixtures were prepared to detect differences of at least 5%. RESULTS: Qualitative contamination at the critical points during preparation, was  seen in groups A and B for every mixture that was processed. No contamination  at all in critical points was seen in any of the mixtures prepared using  PhaSealTM. Statistically significant differences were found between arms A and  C (p < 0.001) and arms B and C (p < 0.001); no differences were found  between arms A and B. CONCLUSIONS: The combination of PhaSealTM system in conjunction with the BD  luer extension for administering hazardous drugs from a tree modality system  has been shown to be the system with the lowest level of contamination during  processing without increasing the time required for preparation of the mixture.

Objetivo: El objetivo de este estudio fue comparar la contaminación ambiental  generada durante la preparación de fluoresceína y el tiempo de preparación  usando tres sistemas cerrados de transferencia diferentes.Método: Estudio comparativo de elaboración de mezclas de fluoresceína con  tres tipos de sistemas cerrados en una unidad de mezclas peligrosas de un  Servicio de Farmacia de un Hospital General Universitario. Se consideró  contaminación ambiental la detectada en los puntos críticos de conexión y las  salpicaduras generadas en cualquier otro punto distinto. La variable principal fue  la detección cualitativa mediante luz ultravioleta de la contaminación  generada cuando se comparan tres sistemas (sistema A: ChemoClave®, sistema  B: válvula SmartSite® y conector Texium®, sistema C: PhaSealTM con  alargadera luer BD). Se prepararon 60 mezclas para poder detectar  diferencias de al menos el 5%.Resultados: Se detectó contaminación en los puntos críticos durante la  preparación en todas las mezclas de los grupos A y B. No se detectó contaminación en ninguna de las mezclas en las que se usó el sistema  cerrado PhaSealTM. Se encontraron diferencias estadísticas entre los grupos A y  C (p < 0,001) y entre los grupos B y C (p < 0,001); no se encontraron diferencias entre los grupos A y B.Conclusiones: La combinación del sistema PhaSealTM y la alargadera luer BD  para administrar fármacos peligrosos en la modalidad de árbol ha mostrado ser  el sistema con el menor nivel de contaminación durante la preparación, sin que  esto se traduzca en aumento en el tiempo de elaboración.

Coumarin/fluorescein-fused fluorescent dyes for rapidly monitoring mitochondrial pH changes in living cells.

On base of the good optical properties of coumarin and fluorescein, we designed and synthesized two coumarin/fluorescein-fused fluorescent dyes (CF dyes), which enlarged the emission wavelength and increased the Stokes shift of fluorescein moiety. The corresponding optical properties of CF dyes were investigated in detail. CF dyes could easily introduce other groups to design different functional molecules. CF dyes also exhibited rapid and sensitive responses to pH values in the range of 4.0-7.4 through the characterization of absorption and fluorescence spectra in buffer solution. More importantly, CF ethyl ester dye (CFE dye) not only showed good cell membrane permeability and low cytotoxicity, but also had the ability to rapidly monitor mitochondrial pH changes in living cells.

Heavy water enhancement of fluorescence signal in reversed-phase liquid chromatography.

Liquid chromatography with fluorescence detection has been used in analyses demanding high sensitivity and selectivity. As majority systems rely on reversed-phase columns with water being the main component of the mobile phase, fluorescent compounds with emission maxima higher than 500 nm might be dynamically quenched. A simple replacement of H2O with D2O enhanced the sensitivity for selected compounds by 10-200%. Affected compounds included an anti-cancer drug doxorubicin, a luminescent probe fluorescein, and naturally occurring forms of vitamin B2. Similar levels of enhancement were obtained by fluorescence spectrometry. Such simple yet effective approach may greatly improve HPLC analyses coupled to fluorescence detection.

Assessment of the Content of Fluorescent Tracer in Granular Feed Mixture.

Background: This paper describes the use of fluorescence induced by UV radiation to evaluate the share of tracer in feed mixture. Methods: For the purpose of this study, three substances were used. They are as follows: Tinopal, Rhodamine B, and Uranine. Tracer in the form of maize or kardi was added to chicken feed before the mixing process. Grains used in the process were grinded in the mill sieve with a mesh size of 4 and 6 mm. The drawn samples of the mixture were illuminated with UV radiation to make grain tracer light, and then the photo was taken with a digital camera. The acquired images were analyzed with the use of a computer program running on the RGB color model, which was the way to obtain essential information about the percentage share of tracer. Results: It was observed that, in the case of kardi grains, the proposed method gives results significantly deviating from the verification method. Conclusions: Only the tests with the use of maize having an average particle diameter of 2.4 mm and tinted with the solution of Rhodamine B led to acceptable results (consensual with the predetermined verification level).

Structure and Distribution of an Unrecognized Interstitium in Human Tissues.

Confocal laser endomicroscopy (pCLE) provides real-time histologic imaging of human tissues at a depth of 60-70 µm during endoscopy. pCLE of the extrahepatic bile duct after fluorescein injection demonstrated a reticular pattern within fluorescein-filled sinuses that had no known anatomical correlate. Freezing biopsy tissue before fixation preserved the anatomy of this structure, demonstrating that it is part of the submucosa and a previously unappreciated fluid-filled interstitial space, draining to lymph nodes and supported by a complex network of thick collagen bundles. These bundles are intermittently lined on one side by fibroblast-like cells that stain with endothelial markers and vimentin, although there is a highly unusual and extensive unlined interface between the matrix proteins of the bundles and the surrounding fluid. We observed similar structures in numerous tissues that are subject to intermittent or rhythmic compression, including the submucosae of the entire gastrointestinal tract and urinary bladder, the dermis, the peri-bronchial and peri-arterial soft tissues, and fascia. These anatomic structures may be important in cancer metastasis, edema, fibrosis, and mechanical functioning of many or all tissues and organs. In sum, we describe the anatomy and histology of a previously unrecognized, though widespread, macroscopic, fluid-filled space within and between tissues, a novel expansion and specification of the concept of the human interstitium.

A simple and cost effective method for preparing FL and LG solutions.

PURPOSE: The purpose of this study was to develop a clinically feasible method for obtaining dye concentrations of 2% fluorescein (FL) and 1% lissamine green (LG) by soaking commercially available dye impregnated strips in saline. METHODS: Calibration curves were established to related known concentrations of dye to prepared FL fluorescence and LG absorbance. To determine the optimum number of dye strips and soaking times (preliminary testing), 1, 2, 3 FL or LG strips were soaked in 200 µl commercially available saline for 0.5, 1, 2, 3, 4 and 5 min, using calibration curves to determine FL and LG concentrations. The best combination of number of dye strips and soaking time was soaking 3FL and 3LG strips for 5 min and these were finally tested in 2 ml centrifuge tubes, selected for ease of use in a clinical setting. RESULTS: Preliminary testing indicated that soaking 3 FL or 3 LG strips for 5 min in saline yielded an average (±standard deviation) of 2.0 ± 0.000% FL and 0.93 ± 0.010% LG. Final testing of FL in centrifuge tubes (strips soaked for 3-15 min) yielded an average of 1.99 ± 0.040% FL, with no significant difference among time periods or dye lots tested. However, LG showed more variable results with an average of 0.80 ± 0.160% LG (5-15 min), with significant differences among dye lots and times (2-way ANOVA, p < 0.05). CONCLUSIONS: This simple, reliable and relatively inexpensive method involves soaking 3 FL or LG strips in saline solution, yielding concentrations close to the 2%FL and 1%LG recommended for clinical trials, although LG showed more variability.

Fluorescence quenching by metal centered porphyrins and poryphyrin enzymes.

Fluorescence spectroscopy and microscopy have been used extensively to monitor biomolecules, especially reactive oxygen species (ROS) and, more recently, reactive sulfide (RSS) species. Nearly all fluorophores are either excited by or emit light between 450 and 550 nm, which is similar to the absorbance of heme proteins and metal-centered porphyrins. Here we examined the effects of catalase (Cat), reduced and oxidized hemoglobin (Hb and metHb), albumin (alb), manganese (III) tetrakis (4-benzoic acid) porphyrin chloride (MnTBAP), iron protoporphyrin IX (hemin), and copper protoporphyrin IX (CuPPIX) on the fluorescence properties of fluorescein. We also examined the effects of catalase and MnTBAP on fluorophores for ROS (dichlorofluorescein, DCF), polysulfides (3',6'-di(O-thiosalicyl)fluorescein, SSP4), and H2S (7-azido-4-methylcoumarin, AzMC) previously activated by H2O2, a mixed polysulfide (H2Sn, n = 1-7) and H2S, respectively. All except albumin concentration dependently inhibited fluorophore fluorescence and absorbed light between 450 and 550 nm, suggesting that the inhibitory effect was physical not catalytic. Catalase inhibition of fluorescein fluorescence was unaffected by sodium azide, dithiothreitol, diamide, tris(2-carboxyethyl)phosphine (TCEP), or iodoacetate, supporting a physical inhibitory mechanism. Catalase and TBAP augmented, then inhibited DCF fluorescence, but only inhibited SSP4 and AzMC fluorescence indicative of a substrate-specific catalytic oxidation of DCF and nonspecific fluorescence inhibition of all three fluorophores. These results suggest caution must be exercised when using any fluorescent tracers in the vicinity of metal-centered porphyrins.

Colored and fluorescent nanofibrous silk as a physically transient chemosensor and vitamin deliverer.

Biodegradable and physically transient optics represent an emerging paradigm in healthcare devices by harnessing optically active system and obviating issues with chronic uses. Light emitting components that can efficiently interact with their environments have advantages of high sensitivity, visibility, and wireless operation. Here, we report a novel combination of silk biopolymer and optically active organic dyes resulting in versatile fluorescent silk nanofibers (FSNs). FSNs generated by the electrospinning method exhibit attractive functions of the doped organic dyes along with programming the system that physically disappear at prescribed time. Red-green-blue (RGB) fluorescent nanofibrous mats, eco-friendly and transient fluorescent chemosensors for acid vapor detection, and disposable membranes for nutrition delivery were successfully demonstrated using FSNs. These functions introduced using four water soluble dyes: rhodamine B, sodium fluorescein, stilbene 420, and riboflavin. The FSN with sodium fluorescein especially, showed a sensing capability for hazardous and volatile hydrochloric acid vapors. Delivering riboflavin (vitamin B2, an important nutrient for skin care) in the FSN to a biological tissue could be observed by tracing the fluorescence of riboflavin.

Fluorescent silica nanoparticles with chemically reactive surface: Controlling spatial distribution in one-step synthesis.

The encapsulation of fluorescent dyes inside silica nanoparticles is advantageous to improve their quality as probes. Inside the particle, the fluorophore is protected from the external conditions and its main emission parameters remains unchanged even in the presence of quenchers. On the other hand, the amine-functionalized nanoparticle surface enables a wide range of applications, as amino groups could be easily linked with different biomolecules for targeting purposes. This kind of nanoparticle is regularly synthesized by methods that employ templates, additional nanoparticle formation or multiple pathway process. However, a one-step synthesis will be an efficient approach in this sort of bifunctional hybrid nanoparticles. A co-condensation sol-gel synthesis of hybrid fluorescent silica nanoparticle where developed. The chemical and morphological characterization of the particles where investigated by DRIFTS, XPS, SEM and SAXS. The nanoparticle fluorescent properties were also assessed by excitation-emission matrices and time resolved experiments. We have developed a one-pot synthesis method that enables the simultaneous incorporation of functionalities, the fluorescent molecule and the amino group, by controlling co-condensation process. An exhaustive characterization allows the definition of the spatial distribution of the fluorescent probe, fluorescein isothiocyanate, inside the particle and reactive amino groups on the surface of the nanoparticle with diameter about 100nm.

Confocal laser-induced fluorescence detector for narrow capillary system with yoctomole limit of detection.

Laser-induced fluorescence (LIF) detectors for low-micrometer and sub-micrometer capillary on-column detection are not commercially available. In this paper, we describe in details how to construct a confocal LIF detector to address this issue. We characterize the detector by determining its limit of detection (LOD), linear dynamic range (LDR) and background signal drift; a very low LOD (~70 fluorescein molecules or 12 yoctomole fluorescein), a wide LDR (greater than 3 orders of magnitude) and a small background signal drift (~1.2-fold of the root mean square noise) are obtained. For detecting analytes inside a low-micrometer and sub-micrometer capillary, proper alignment is essential. We present a simple protocol to align the capillary with the optical system and use the position-lock capability of a translation stage to fix the capillary in position during the experiment. To demonstrate the feasibility of using this detector for narrow capillary systems, we build a 2-µm-i.d. capillary flow injection analysis (FIA) system using the newly developed LIF prototype as a detector and obtain an FIA LOD of 14 zeptomole fluorescein. We also separate a DNA ladder sample by bare narrow capillary - hydrodynamic chromatography and use the LIF prototype to monitor the resolved DNA fragments. We obtain not only well-resolved peaks but also the quantitative information of all DNA fragments.

A multi-module microfluidic platform for continuous pre-concentration of water-soluble ions and separation of oil droplets from oil-in-water (O/W) emulsions using a DC-biased AC electrokinetic technique.

A novel continuous flow microfluidic platform specifically designed for environmental monitoring of O/W emulsions during an aftermath of oil spills is reported herein. Ionized polycyclic aromatic hydrocarbons which are toxic are readily released from crude oil to the surrounding water phase through the smaller oil droplets with enhanced surface area. Hence, a multi-module microfluidic device is fabricated to form ion enrichment zones in the water phase of O/W emulsions for the ease of detection and to separate micron-sized oil droplets from the O/W emulsions. Fluorescein ions in the water phase are used to simulate the presence of these toxic ions in the O/W emulsion. A DC-biased AC electric field is employed in both modules. In the first module, a nanoporous Nafion membrane is used for activating the concentration polarization effect on the fluorescein ions, resulting in the formation of stable ion enrichment zones in the water phase of the emulsion. A 35.6% amplification of the fluorescent signal is achieved in the ion enrichment zone; corresponding to 100% enrichment of the fluorescent dye concentration. In this module, the main inlet is split into two channels by using a Y-junction so that there are two outlets for the oil droplets. The second module located downstream of the first module consists of two oil droplet entrapment zones at two outlets. By switching on the appropriate electrodes, either one of the two oil droplet entrapment zones can be activated and the droplets can be blocked in the corresponding outlet.

Variaciones en la técnica del trasplante limbar autólogo / Variations in the technique for autologous limbal transplantation

OBJETIVO: Presentar los resultados del uso de un único segmento de autoinjerto limbar combinado con trasplante de membrana amniótica y epiteliectomías conjuntivales sectoriales secuenciales postoperatorias en 2 pacientes con insuficiencia límbica unilateral total. CONCLUSIONES: Un solo segmento de autoinjerto limbal junto con el trasplante de membrana amniótica puede ser suficiente para restaurar una superficie corneal estable, siendo en ocasiones necesario realizar en el postoperatorio epiteliectomías conjuntivales secuenciales en zonas remanentes de epitelio anómalo

OBJECTIVE: To present the results on the use of a single block limbal autograft, combined with amniotic membrane transplantation and sectoral sequential postoperative epitheliectomy of the conjunctiva in 2 patients with unilateral total limbal stem cell deficiency. CONCLUSIONS: A single block limbal autograft combined with amniotic membrane transplantation may be sufficient to restore a stable corneal surface, but sometimes sequential sectoral conjunctival epitheliectomy may be required to treat anomalous epithelial remnants