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BACKGROUND: Our previous studies found that the polypeptide of Cornus cervi Colla can promote bone growth, which has a good application prospect in the treatment of bone diseases. However, how Cornus cervi Colla works in the body and the principle are not clear. OBJECTIVE: To study the in vivo distribution and tracing of Cornus cervi Colla using fluorescence labeling and tracer technique. METHODS: Cornus cervi Colla was fluorescently labeled using fluorescein isothiocyanate, and the labeling results were detected by fluorescence imaging and UV spectral scanning. Successfully labeled Cornus cervi Colla was injected into mice by gavage, and the absorption of Cornus cervi Colla into blood was detected by laser confocal microscopy, and the distribution of Cornus cervi Colla in mice was detected by small animal in vivo imager. The distribution of Cornus cervi Colla in the mice was detected by laser confocal microscopy. Samples were taken from serum and bone at the time of the strongest fluorescence, and gel electrophoresis was carried out on serum and bone tissue protein solutions, and the components of Cornus cervi Colla absorbed into target organs were determined by secondary mass spectrometry. RESULTS AND CONCLUSION: The fluorescent markers were successfully separated by dextran gel chromatography, and the fluorescence imaging and ultraviolet spectrum scanning proved that the labeling was successful, and the fluorescence substitution degree of FITC-labeled Cornus cervi Colla was 0.953%. The fluorescence intensity of the components of Cornus cervi Colla in the blood showed that Cornus cervi Colla was most distributed in serum after oral administration for 2 hours. The fluorescence images of mice at different times were the same as those of bilateral femur and tibia, indicating that Cornus cervi Colla could play a role by entering the bone. Compared with UniProt database, secondary mass spectrometry showed that the peptide was a characteristic fragment of decorin. It is proved that decorin in Cornus cervi Colla can enter the bone to play a therapeutic role. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing has been widely used to enhance reservoir permeability during the extraction of shale gas. As one of the external input parameters, injection rate has a significant impact on formation breakdown pressure and the complexity of hydraulic fractures. To gain deeper insights into the effect of injection rate on breakdown pressure and fracture morphology, we conducted five hydraulic fracturing experiments on Changning shale in the laboratory. We used five different injection rates between 3 and 30 mL/min to fracture cylindrical core samples with 50 mm in diameter and 100 mm in length. We monitored acoustic emissions and surface displacements during the tests, and analyzed the fracture pattern post mortem by using a fluorescent tracer. We find a semi-logarithmic relationship between the breakdown pressure and the injection rates. Second, we find that it is the injection rate that dictates sample deformation and crack formation during breakdown rather than the fluid volume injected during the whole process. The analysis of amplitudes and frequency of acoustic signals indicates that hydraulic fracturing of Changning shale is overall dominated by tensile fractures (> 60%). However, at low injection rates, shear events are facilitated before rock breakdown. On the other hand, high injection rates result in reducing fracture tortuosity and surface roughness due to limited fluid infiltration in the relatively short injection window. We close this study with a conceptual model to explain the difference between fluid infiltration (low injection rates) and the loading rate effect (high injection rate) in low-permeability shale rocks. The findings obtained in this study can help to adjust injection rates in the field to economically and safely produce gas from shale. Highlights: Rock expansion upon breakdown is dominated by instantaneous crack opening caused by injection rates. Low injection rates reduce the breakdown strength by activating shear cracks in a larger fluid infiltration zone. High injection rates have limited effects on fracture morphology. A theoretical model is proposed to elucidate the competing mechanism between fluid infiltration and the loading rate effect. [ABSTRACT FROM AUTHOR]

Transmedia migration of water is the key factor influencing the bond and shear mechanical properties of the interface system between soil and concrete. In numerous engineering projects, failures often occur at the soil–concrete interface, making the study of transmedia water migration in soil–concrete interface systems highly significant. This research based on the tracer properties of fluorescein to conduct a transmedia water infiltration test on silty clay–concrete interface systems. A fluorescent quantitative method was proposed to determine the moisture content within the concrete profile. The study investigated the migration of the wetting front, changes in water content, moisture distribution across the profiles of both media, and the spatial and temporal variations of soil moisture during the transmedia water migration process. The characteristics of transmedia water migration were compared under different initial soil water contents (IWC). Results demonstrated that the water distribution law of silty clay–concrete interface systems was not monotonous; notably, the water content in the interface area increased significantly. An increase in IWC inhibited the migration of the wetting front and the water content increment of the silty clay, while promoting the progression of saturation. Additionally, the water migration in the concrete was influenced by the silty clay. The proposed fluorescent quantitative method demonstrated high measurement accuracy. [Display omitted] • In the interface area, the water content of the two media increased significantly. • The concrete water migration is affected by silty clay. • Initial water content of the soil affect transmedia water migration law considerably. • The proposed fluorescent quantitative method can characterize concrete water content. [ABSTRACT FROM AUTHOR]

Summary: Background: Personal protective equipment (PPE) is effective in preventing coronavirus disease (COVID-19) infection. Resident knowledge of proper use and effective training methods is unknown. We hypothesise that contamination decreases and knowledge increases after a formalised PPE educational session. Methods: Participants included first year interns during their residency orientation in June 2020. Before training, participants took a knowledge test, donned PPE, performed a simulated resuscitation, and doffed. A standardised simulation-based PPE training of the donning and doffing protocol was conducted, and the process repeated. Topical non-toxic highlighter tracing fluid was applied to manikins prior to each simulation. After doffing, areas of contamination, defined as discrete fluorescent areas on participants' body, was evaluated by ultraviolet light. Donning and doffing were video recorded and asynchronously rated by two emergency medicine (EM) physicians using a modified Centers for Disease Control and Prevention (CDC) protocol. The primary outcome was PPE training effectiveness defined by contamination and adherence to CDC sequence. Results: Forty-eight residents participated: 24 internal medicine, 12 general surgery, 6 EM, 3 neurology, and 3 psychiatry. Before training, 81% of residents were contaminated after doffing; 17% were contaminated after training (P

Objective: Study the repair effect of tilapia collagen on acute wounds, and the effect on the expression level of related genes and its metabolic direction in the repair process.Materials and methods: After the full-thickness skin defect model was constructed in standard deviation rats, the wound healing effect was observed and evaluated by means of characterization, histology, and immunohistochemistry. RT-PCR, fluorescence tracer, frozen section and other techniques were used to observe the effect of fish collagen on the expression of related genes and its metabolic direction in the process of wound repair.Results: After implantation, there was no immune rejection reaction, fish collagen fused with new collagen fibers in the early stage of wound repair, and was gradually degraded and replaced by new collagen in the later stage. It has excellent performance in inducing vascular growth, promoting collagen deposition and maturation, and re-epithelialization. The results of fluorescent tracer showed that fish collagen was decomposed, and the decomposition products were involved in the wound repair process and remained at the wound site as a part of the new tissue. RT-PCR results showed that, without affecting collagen deposition, the expression level of collagen-related genes was down-regulated due to the implantation of fish collagen.Conclusion: Fish collagen has good biocompatibility and wound repair ability. It is decomposed and utilized in the process of wound repair to form new tissues.

The environment-friendly scale inhibitor polyaspartic acid (PASP) was grafted with tyrosine (Tyr) with fluorescent property and glutamic acid (Glu) with scale inhibition group. And a new environment-friendly fluorescent tracer scale inhibitor Tyr-Glu-PASP was prepared, which improved the CaSO4 inhibition performance of PASP and added the fluorescent tracer effect. The synthesized product was characterized by IR, TGA and fluorescence spectrum. The results show that PASP, where phenolic hydroxyl group, carboxyl group, amide group and other scale inhibition groups were added, had excellent thermal stability. The results of scale inhibition performance research show that the scale inhibition rate of CaSO4 could reach 96% when the ratio of total amino acid to PSI monomer was 0.6, the dosage concentration was 4 mg/L and the calcium ion concentration was 6 000 mg/L. The crystal changes of calcium sulfate were studied by scanning electron microscope, X-ray powder diffraction analysis and fluorescence spectrometry. The results show that CaSO4 changed from regular columnar structure to agglomerate structure, and the crystal grains became smaller, which promoted the solubility of calcium scale crystal grains in water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Road collapse disasters are sudden, concealed, and pose high risks to public safety. • Microscopic erosion process of cohesive soil can be divided into five change phases. • Macroscopic evolution of the road collapse exhibited five different characteristics. • Soil settlement ring appeared upstream inward convergence and downstream outward divergence. Drainage pipe leakage is the primary cause of road collapse in Beijing, where cohesive soils are prevalent. Nevertheless, the influence of drainage flow velocity on cohesive soil erosion and road collapse remains unclear. Using the tracer technology, this study analyzes the microscopic erosion process of the cohesive soil under different drainage flow velocities, whereas the macroscopic evolution characteristics of road collapse were examined through camera images, soil settlement, and soil dry density. Based on the results, the microscopic cohesive soil erosion and macroscopic road collapse evolution can be categorized into five phases. As the drainage flow velocity increased from 0.045 to 0.067 and 0.089 m/s, the critical seepage range within the fluorescent tracer images decreased by 6.76 % and 9.32 %, respectively, demonstrating a power–law decline. Additionally, the settlement ring exhibited characteristics of upstream inward convergence and downstream outward divergence. These results can enhance the comprehension of road collapse mechanisms. [ABSTRACT FROM AUTHOR]

The Wilms tumor suppressor gene Wt1 encodes a zinc finger transcription factor, which is highly conserved among vertebrates. It is a key regulator of urogenital development and homeostasis but also plays a role in other organs including the spleen and the heart. More recently additional functions for Wt1 in the mammalian central nervous system have been described. In contrast to mammals, bony fish possess two paralogous Wt1 genes, namely wt1a and wt1b. By performing detailed in situ hybridization analyses during zebrafish development, we discovered new expression domains for wt1a in the dorsal hindbrain, the caudal medulla and the spinal cord. Marker analysis identified wt1a expressing cells of the dorsal hindbrain as ependymal cells of the choroid plexus in the myelencephalic ventricle. The choroid plexus acts as a blood-cerebrospinal fluid barrier and thus is crucial for brain homeostasis. By employing wt1a mutant larvae and a dye accumulation assay with fluorescent tracers we demonstrate that Wt1a is required for proper choroid plexus formation and function. Thus, Wt1a contributes to the barrier properties of the choroid plexus in zebrafish, revealing an unexpected role for Wt1 in the zebrafish brain.

In this study, nitrobenzene was used as dummy template to synthesize a type of specific molecularly imprinted microspheres for chloramphenicol, and 4‐nitroaniline was coupled with three fluorophores to synthesize three fluorescent tracers. Then a competitive fluorescence method was developed on a conventional microplate for detection of chloramphenicol in chicken and pork samples. This method contained only one sample‐loading step, so one assay was finished within 30 min. The IC50 was 1.8 ng/ml, and the limit of detection was 0.06 ng/g. The recoveries from chloramphenicol‐fortified blank meat samples were in the range 67.5–96.2%. Furthermore, this method could be recycled three times. The detection results for some real meat samples were identical to that of a LC–MS/MS method. Therefore, this method could be used as a practical tool for routine screening for the residue of chloramphenicol in large number of meat samples. [ABSTRACT FROM AUTHOR]

How to monitor and identify fracture initiation and propagation is a significant work for the laboratory experiment studies of hydraulic fracturing. In this paper, four main monitoring methods are reviewed and compared through the tri-axial fracturing experiments with natural shale outcrops, including tracer labeling, acoustic emission (AE) monitoring, computerized tomography (CT) scanning and visual fracturing method. Results show that for tracer labeling, fluorescent tracer could visually monitor the hydraulic fracture distribution morphologies, but it has a poor compatibility with slippery water. For the method of AE monitoring, dynamic three dimensional (3D) hydraulic fracture propagation process can be monitored by fixing AE sensors on specimen surfaces. However, the AE signal might display inconsistency with fracture path, which is affected by shale heterogeneity, natural fractures and bedding planes. For the method of CT scanning, many internal rock features can be well recognized, including the location of primary and activated fractures, fracture scales and the interactions between hydraulic fracture and natural fractures. However, CT scanning method cannot identify some micron-and nanoscale fractures characteristics. For the method of visual fracturing, the injected low-temperature metal can extract the fractures skeleton and measure fracture morphologies precisely, but temperature have a significant impact on experiment results. Therefore, combinations of multiple monitoring methods are recommended in laboratory experiment studies. For example, the combination of AE monitoring and CT scanning can effectively identify the propagation behavior of complex fracture network. [ABSTRACT FROM AUTHOR]

In this study, molecularly imprinted microspheres of a type capable of recognising amantadine and rimantadine were first synthesised, and three fluorescent tracers based on dansyl chloride, fluorescein isothiocyanate and 5-carboxytetramethylrhodamine were also synthesised. These reagents were used to develop and optimise a direct competitive fluorescence method on conventional 96-well microplate for detection of the two analytes. Results showed that this method achieved simple operation procedure, rapid assay process (30 min), high sensitivity (limits of detection 0.04–0.05 ng mL−1) and acceptable recycle performance (five times). After optimisation of several parameters, this method was used to detect amantadine and rimantadine in chicken muscle samples. Their recoveries from standards fortified blank samples were in the range of 62.3–93.7%. The analysis results for some real chicken samples were consistent with a confirmatory LC-MS/MS method. Therefore, this method could be used as a rapid, simple and accurate tool for routine screening the residues of amantadine and rimantadine in a large number of chicken muscle samples. [ABSTRACT FROM AUTHOR]

Cell monolayers, including endothelial and epithelial cells, play crucial roles in regulating the transport of biomolecules to underlying tissues and structures via intercellular junctions. Moreover, the monolayers form a semipermeable barrier across which leukocyte transmigration is tightly regulated. The inflammatory cytokines can disrupt the epithelial and endothelial permeability, thus the reduced barrier integrity is a hallmark of epithelial and endothelial dysfunction related with numerous pathological conditions, including cancer-related inflammation. Therefore, the assessment of barrier function is critical in in vitro models of barrier-forming tissues. This review summarizes the commercially available in vitro systems used to measure the permeability of cellular monolayers. The presented techniques are separated in two large groups: macromolecular tracer flux assays, and electrical impedance measurement-based permeability assays. The presented techniques are briefly described and compared.

Following intrathecal injection of fluorescent tracers, ex vivo imaging of brain vibratome slices has been widely used to study the glymphatic system in the rodent brain. Tracer penetration into the brain is usually quantified by image-processing, even though this approach requires much time and manual operation. Here, we illustrate a simple protocol for the quantitative determination of glymphatic activity using spectrophotofluorometry. At specific time-points following intracisternal or intrastriatal injection of fluorescent tracers, certain brain regions and the spinal cord were harvested and tracers were extracted from the tissue. The intensity of tracers was analyzed spectrophotometrically and their concentrations were quantified from standard curves. Using this approach, the regional and dynamic delivery of subarachnoid CSF tracers into the brain parenchyma was assessed, and the clearance of tracers from the brain was also determined. Furthermore, the impairment of glymphatic influx in the brains of old mice was confirmed using our approach. Our method is more accurate and efficient than the imaging approach in terms of the quantitative determination of glymphatic activity, and this will be useful in preclinical studies. [ABSTRACT FROM AUTHOR]

With the development of agricultural aviation technologies and their application in agricultural production, plant protection unmanned aerial vehicle (UAV) has been widely used to control pests and diseases of crops. The high speed rotation of the rotor in the UAV produces a powerful downwash affecting the distribution of pesticide droplets on the ground. Understanding spatial distribution of these droplets on the ground is important to evaluate application quality of the pesticides and plays an important role in improving the spray system in UAV and optimizing its operating parameters. Current methods for measuring the droplet deposition distributions use a number of collectors placed regularly on the ground to receive the droplets and measured their sizes; it is difficult for them to effectively obtain the deposition of all droplets result due to the downwash of UAV. This paper presents a new method to resolve this problem by improving accuracy and spatial continuity of pesticide droplets measurement applied by an unmanned helicopter. The flying parameters of a 3WQF-80-10 unmanned helicopter used to spray pesticides were obtained from the high-precision Beidou navigation system, and the RQT-C-3 fluorescent whitening tracer with mass fraction of 1.0% was used as the proxy for the pesticides. Two droplet collection methods: one used continuous strip paper and the other one used individual water sensitive paper, were used to measure the droplets deposition distribution. We divided the experimental field into three areas, with Areas 1 and 2 spaced 3 m apart, and Areas 2 and 3 spaced 1m apart. A metal bracket 8 m log and 0.5 m away from the ground was placed in each area. Prior to the experiment, a paper tape was fixed on the surface of the bracket and the water-sensitive paper cards were placed evenly in the area 0.5 m away from the paper tape. There were one paper tape and 15 water sensitive papers in each area, and a total of six spray tests were performed based on pro-designed flight parameters. The combinations of flight speed and flight height were: 2 m/s and 3 m, 2 m/s and 6 m, 2 m/s and 9 m, 3 m/s and 3 m, 3 m/s and 6 m, and 4 m/s and 9 m. The paper tape was detected by fluorescence spectroscopy analysis, and the water sensitive papers were scanned using an image processing software to obtain droplet deposition coverage rate. The results showed that distribution curves of the coverage rate obtained by the paper tape method coupled with the fluorescence spectrum tracer were consistent with that obtained from the images of the water sensitive paper method, with the R² being 0.88~0.96. Because not all fine droplets fell on the water sensitive papers due to the effect of the high speed rotating rotor, the coverage rate curve measured by the continuous fluorescence method had multiple peaks and the value of its coverage rate was higher than that measured from the water sensitive paper method. When the unmanned helicopter flew at speed of 2 m/s and height of 3 m, the coverage ratio obtained from the continuous fluorescence method was up 16.92% compared to that sampled from the individual water-sensitive paper method, while when the flight speed was 4 m/s at height of 9 m, the coverage ratio in the latter was 97.77% higher than in the former. In terms of the impacts of unmanned helicopter operating conditions on coverage rate, when the helicopter flew at 2 m/s and height of 3 m, the coverage rate of the droplets obtained from the two methods were the highest, being 8.34% for the continuous fluorescence method and 7.14% for the individual paper method. With the flight height and speed increasing, the spatial coverage rate of the droplets decreased. In summary, the high-speed rotor of UAV generates a downwash, making the droplets of pesticides move in different directions and resulting in a large spatial difference in their deposition on the ground. Therefore, the continuous sampling method is more adequate to evaluate the spatial distribution of the droplets. This study has implication for study on detecting deposition of pesticides and other agrochemicals applied by UAV. [ABSTRACT FROM AUTHOR]

Highlights • We developed a new spray deposition pattern measurement system (SDPMS). • In tandem, we developed an associated analysis program. • The system relies on fluorescence tracers and spectral analysis. • We validated the system in field tests with UAV spraying compared with WSP cards. • The SDPMS and WSP results showed high correlations >0.89. Abstract To complement shortages of discrete sampling data and improve the detection accuracy of droplet deposition in unmanned aerial vehicle (UAV) spraying, we developed a new spray deposition pattern measurement system (SDPMS) based on a fluorescent tracer and spectral analysis. Then, we evaluated the system performance in two field spraying experiments in comparison with water-sensitive paper results. The system comprises a fluorescence scanner and spectral analysis program. The fluorescence scanner includes an ultraviolet light, spectrometer, far end controller, stepping motor, and sample reel. First, 1.0% fluorescent tracer solution is sprayed, and the droplets are collected on a paper strip. Then, the paper strip is scanned with the fluorescence scanner, and a set of fluorescence intensity values is collected and processed by the spectral analysis program. Finally, the spray deposition pattern is calculated. The experimental results showed that the spray deposition pattern from the SDPMS had a 0.89 correlation coefficient with that of water-sensitive paper. A linear regression model between fluorescence intensity and deposit coverage was constructed, with a coefficient of determination of 0.91 (F = 61.8845, P < 0.001). In addition, a linear regression model between fluorescence intensity and volume rate was constructed, with a coefficient of determination of 0.89 (F = 51.6639, P < 0.001). The SDPMS and field experiments offer a good foundation for the development of an improved system compatible with UAV spraying. [ABSTRACT FROM AUTHOR]

Systemic seed treatment uptake was investigated in seeds and seedlings using fluorescent tracers to mimic systemic agrochemicals. Soybean was used as the model as soybean has the permeable seed coat characteristic to both charged and noncharged molecules. The purpose of the paper is to (1) screen 32 fluorescent tracers and then use optimal tracers for seed and seedling uptake, (2) investigate varietal differences in seed uptake, (3) examine the distribution of tracer uptake into 14-day-old seedlings, and (4) study the relationship between seed treatment lipophilicity, measured as log P on seed and root uptake. The major chemical families that displayed both seed and seedling uptake were coumarins and xanthenes. Seed uptake of coumarin 120 ranged from 1.1% to 4.8% of the applied seed treatment tracer from 15 yellow-seeded varieties. Rhodamine B, a xanthene compound uptake in seedlings, showed translocation from the applied seed treatment to all seedling tissues. Most of the tracer was measured in the hypocotyl and root, with lesser amounts in the epicotyl and true leaves. Log P is well documented in the literature to model systemic uptake by roots, but log P of the tracers were not related to seed uptake.

Introduction: Proper placental function is essential for optimal fetal growth in utero. Placental transfer of nutrients to the fetus can be measured using radiolabelled tracers, but non-radioactive methods have potential advantages. This study aimed to develop a fluorescence-based method to measure placental glucose transport in mice.Methods: Time course and localisation of the IRDye 800CW 2-deoxyglucose were recorded (Lumina IVIS Live Imaging System) following tail vein injection into anaesthetised late pregnant mice. Fluorescent signals in placental and fetal tissues were assessed after injecting conscious dams with 10 nmol IRDye 800CW 2-deoxyglucose (3, 30, 60, 120 min) or vehicle. Specificity of dye uptake was determined by comparing uptake of IRDye 800CW conjugated to 2-deoxyglucose or carboxylate, at 2 and 24 h. Finally, we assessed relationships of fetal size and umbilical blood flow velocities with relative dye uptake.Results: In late pregnant mice, uterine fluorescent signal localised rapidly over placentas and remained consistent for >1 h. Signal intensity in whole and homogenised tissues increased in fetuses and decreased in placentas after 3 min and stabilised by 30 min post-injection. Relative fetal dye uptake at 2 and 24 h was greater in littermates with the highest compared to lowest placental efficiency; signals were similar for 2-deoxyglucose- or carboxylate-conjugated dyes. Relative fetal dye uptake correlated positively with fetal weight and placental efficiency and negatively with umbilical artery resistance indices.Conclusions: Fetal uptake of IRDye 800CW correlates with markers of placental blood flow and fetal growth, but does not specifically measure placental glucose transport. [ABSTRACT FROM AUTHOR]

• A novel fluorescent dispersed particle gel (FDPG) with fluorescent properties was constructed. • The fluorescence characteristic and other properties of the FDPG was systematically evaluated. • The ability of the FDPG to identify the formation breakthrough flow channels was verified. The breakthrough flow channel generated by formation heterogeneity has severely restricted oil recovery improvement, and its identification and control methods have received extensive attention. In this study, we developed a novel fluorescent dispersed particle gel (FDPG) for identifying and regulating breakthrough flow channels based on the dispersed particle gel (DPG). A copolymer of acryloyl fluorescein and acrylamide (PAMAF) was synthesized by free-radical copolymerization for the preparation of the FDPG. The fluorescence properties and identification method of FDPG were systematically investigated. The results showed that the FDPG had stable fluorescence properties, and its concentration showed a linear relationship with fluorescence intensity. The excitation and emission wavelengths of FDPG fluorescence fall within the interval that can avoid the influence of crude oil on its detection. FDPG can accurately reflect the migration of particles in the formation and avoid the chromatographic separation effect. FDPG has excellent injection and migration properties and can effectively control the high permeability layer after ageing. By analysing the output of the FDPG, breakthrough flow channels that exist between formation layers and within well groups can be effectively identified. FDPG provides a promising approach for identifying breakthrough flow channels and monitoring particle profile control agents. [ABSTRACT FROM AUTHOR]

The vast majority of fluorochromes are organic in nature and none of the few existing chelates have been applied as histological tracers for localizing brain anatomy and pathology. New method In this study we have developed and characterized a Europium chelate with the ability to fluorescently label normal and pathological myelin in control and toxicant-exposed rats, as well as the amyloid plaques in aged AD/Tg mice. Results This study demonstrates how Euro-Glo can be used for the detailed labeling of both normal myelination in the control rat as well as myelin pathology in the kainic acid exposed rat. In addition, this study demonstrates how E-G will label the shell of amyloid plaques in an AD/Tg mouse model of Alzheimer’s disease a red color, while the plaque core appears blue in color. The observed E-G staining pattern is compared with that of well characterized tracers specific for the localization of myelin (Black-Gold II), degenerating neurons (Fluoro-Jade C), A-beta aggregates (Amylo-Glo) and glycolipids (PAS). Comparisons with existing methods This study represents the first time a rare earth metal (REM) chelate has been used as a histochemical tracer in the brain. This novel tracer, Euro-Glo (E-G), exhibits numerous advantages over conventional organic fluorophores including high intensity emission, high resistance to fading, compatibility with multiple labeling protocols, high Stoke’s shift value and an absence of bleed-through of the signal through other filters. Conclusions Euro-Glo represents the first fluorescent metal chelate to be used as a histochemical tracer, specifically to localize normal and pathological myelin as well as amyloid plaques. [ABSTRACT FROM AUTHOR]

Sediment dynamics is a complex subject, playing an important role in coastal areas. The interaction between wave action and sediment particles is determinant to understand sediment transport processes. The knowledge of sediment transport comprising sand mixtures is relevant as coastal areas, usually, present heterogeneities of sediment particle sizes in the horizontal and vertical directions, denoting the existence of selective transport processes. This study investigates the effects of non-cohesive size-graded sands on sediment transport fluxes to understand selective transport mechanisms under wave-dominated conditions. A laboratory experiment was carried out at the large wave flume (Großer Wellenkanal, GWK) in Hannover, considering distinct sediment mixtures between two well-sorted sands with median grain sizes of 0.21 mm and 0.58 mm. The experiments were carried out for four sediment bed configurations with two different wave energy conditions. A fluorescent sand tracer technique was implemented to measure total and fractional net sediment transport rates and the outcomes are compared with the ones obtained with the mass conservation method. The experimental results show the occurrence of the interaction between different sand fractions: a decrease in the transport of fine sediments and an enhancement of the transport of the coarse sediments as the percentage of coarse sediments in the bed mixture increases. These effects are larger as the coarser fraction in the sand bed increases and they are noticeable for different sediment transport regimes (sheet flow and rippled beds). • Laboratory experiments were carried with sediment mixtures of fluorescent tracer. • The effects of size-graded sand on sediment transport fluxes were studied. • Interaction between distinct fractions modified transport rates of each fraction. [ABSTRACT FROM AUTHOR]

Operator exposure to spray applied with knapsack sprayers was measured in the open field during the spraying of the low, medium and high plants (strawberries, young apple orchard and bearing fruits one). The samples were attached to the protective clothes in 13 locations. The BSF fluorescent tracer was added to the spray. The operator exposure was expressed as the part of the dose applied (ppm). The data on operator exposure was used to predict the risk for operator. The risk for humans was done by computer modeling according to German BBA model, taking into account field data for different sprayer technical conditions and 15 different pesticides. The most important influence of the sprayer technical condition on the operator exposition and the human health risk was observed for high crops.

Chain-like chitosan-sodium tripolyphosphate (CS-TPP) nanocomposite was prepared by an aqueous solution route. Then fluorescently active 6-carboxyl luciferin (6-FAM) was modified onto CS-TPP surface to afford CS-TPP-6-FAM nanocomposite (CS-TPP-6-FAM) with fluorescent activity. Onto the surface of CS-TPP-6-FAM was grafted bioactive carboxymethyl β -cyclodextrin (CβCD) to obtain CS/TPP/FAM/CβCD that can separate maltose binding protein tagged (MBP-tagged) fusion proteins from E. coli lysate. Findings demonstrate that CS-TPP-6-FAM-CβCD has an average diameter of 22 nm and a chain length of 70 nm. Its adsorption kinetic data can be described by Langmuir isotherm equation and the pseudo 2nd kinetic model, corresponding to high protein binding capacity for MBP-tagged PYL3. Furthermore, CS-TPP-6-FAM-CβCD dispersed in Hoagland nutrient solution can be adsorbed by tobacco through vascular bundle channels. Therefore, CS-TPP-6-FAM-CβCD could have promising applications in separating MBP-tagged fusion proteins from E. coli lysate and in monitoring the growth of plants as the fluorescent tracer. • Chain-like CS-TPP nanoparticles were prepared by an aqueous solution route. • Modified CS-TPP-6-FAM nanospheres showed good fluorescence tracing properties. • These nanospheres could be used to specifically separate MBP-tagged fusion proteins. • The nanospheres can enter into the cells of the tobacco through the vascular bundle channels. [ABSTRACT FROM AUTHOR]

The first impounding of the Bumbuna dam was subject to unexpected high seepages discharge (up to 550 l/s) from the foundation drains. Fluorescent tracer tests, commonly used for hydrogeological study of porous and karst aquifer, were performed to locate the seepage zones. Solutions of 3 different fluorescent tracers (Uranine, Sulforhodamine-B and Tinopal CBS-X) were injected in the reservoir at regularly spaced points down to a depth of 80 m. Tracer concentration in the seepage water from the foundation drains was continuously monitored by high resolution fluorometers with detection limit as low as 0.02 ppb. A total of 107 tests were performed in two separate campaigns conducted in January–February and October–December 2009. Concentration curves recorded from each test were analyzed to determine the time of first response to the injection (detection time) and the quantity of tracer returned from each test (restitution). Maps of minimum detection time and maximum tracer restitution were generated to identify the position of leakages. Seepage mitigation works were planned on the base of test results and completed in the dry season after the drawdown of the reservoir. Works consisted in the additional grouting along the grout curtain, sealing of fissures on the bituminous layer and installation of a PVC membrane on the dam upstream face. Inspection of the upstream dam face confirmed the presence of damages in the areas identified by tracer tests. Since completion of seepage mitigation works the dam operated satisfactorily with maximum seepage from the foundation of 70 l/s. [ABSTRACT FROM AUTHOR]

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Coal seam water injection can effectively prevent dust pollution and coal mining disasters, such as coal bumps and coal seam fires. However, the quantitative determination of the range where water can reach during the water injection remains a challenge and there is no effective method reported for the measurement yet. Herein, we introduce the fluorescent tracers widely used in oil field into the wetting range detection of coal seam water injection. Three commonly used fluorescent tracers, fluorescein sodium, calcein disodium, and fluorescein isothiocyanate (FITC), were examined for their performances in detecting the wetting area of coal seam water injection. Considering the two migration stages, wetting and seepage, of the water injected in coal seam, the bottom-up imbibition and seepage experiments were respectively conducted on the fluorescent tracers, and the fluorescence intensities of the tracer solutions before and after the seepage experiment were measured. The results suggest that both fluorescein sodium and calcein disodium promote, but FITC inhibits the wetting stage. Fluorescein sodium promotes the seepage, but calcein disodium and FITC only do at low concentrations. Due to the retention effect, the permeability coefficients of all of the tracers show decreasing trends as the experiment proceeded. • Effects of different types of fluorescent tracers on the wetting and seepage stages of coal seam water injection. • Effects of different concentrations of fluorescent tracers on the wetting and seepage stages of coal seam water injection. • Feasibility analysis of fluorescent tracer in the field of tracing coal seam water injection and wetting range. [ABSTRACT FROM AUTHOR]