Yellow Fluorescent Dye Research Articles

Comparison of Golgi-Cox and Intracellular Loading of Lucifer Yellow for Dendritic Spine Density and Morphology Analysis in the Mouse Brain

Dendritic spines are small protrusions on dendrites that serve as the postsynaptic site of the majority of excitatory synapses. These structures are important for normal synaptic transmission, and alterations in their density and morphology have been documented in various disease states. Over 130 years ago, Ramón y Cajal used Golgi-stained tissue sections to study dendritic morphology. Despite the array of technological advances, including iontophoretic microinjection of Lucifer yellow (LY) fluorescent dye, Golgi staining continues to be one of the most popular approaches to visualize dendritic spines. Here, we compared dendritic spine density and morphology among pyramidal neurons in layers 2/3 of the mouse medial prefrontal cortex (mPFC) and pyramidal neurons in hippocampal CA1 using three-dimensional digital reconstructions of (1) brightfield microscopy z-stacks of Golgi-impregnated dendrites and (2) confocal microscopy z-stacks of LY-filled dendrites. Analysis of spine density revealed that the LY microinjection approach enabled detection of approximately three times as many spines as the Golgi staining approach in both brain regions. Spine volume measurements were larger using Golgi staining compared to LY microinjection in both mPFC and CA1. Spine length was mostly comparable between techniques in both regions. In the mPFC, head diameter was similar for Golgi staining and LY microinjection. However, in CA1, head diameter was approximately 50% smaller on LY-filled dendrites compared to Golgi staining. These results indicate that Golgi staining and LY microinjection yield different spine density and morphology measurements, with Golgi staining failing to detect dendritic spines and overestimating spine size.

Carbazole-Anthranyl π-Conjugates as Small and Stable Aggregation-Induced Emission-Active Fluorogens: Serving as a Reusable and Efficient Platform for Anticounterfeiting Applications with an Acid Key and Multicolor Ink for a Quill Pen.

Being a unique, simple, and inexpensive approach, continuous development on the fluorescence-based technologies remains active in fluorescent anticounterfeiting. A number of polymeric, nano-, carbon dot, and rare-earth oxide materials were preferably explored for such applications, but the complex synthesis, purity, and high cost are the major concerns to make these materials accessible for commercial applications. To address these difficulties, we herein report simple mono-carbazole-linked anthranyl π-conjugates that are synthesized in a gram scale via an inexpensive and convenient route. These unsymmetrically substituted new π-conjugates are found to be promising blue-shifted aggregation-induced emission-active fluorogens (AIEgens) having a distinct color on varying substituents with electron-rich (−NEt2) and electron-poor (−CN) functionalities. The direct link of a single carbazole unit with an anthracenyl π-conjugate possibly enforces the achievement of a highly twisted molecular structure, accountable for the AIE characteristics. The π-conjugate with −NEt2 substituents is established to be highly sensitive under protonation–deprotonation stimuli by a sharp and rapid fluorescence color change [yellow (Φf = 37%) to green (Φf = 39.4%)] in the solid state (no fluorescence on/off). Upon the exposure of the base vapors (deprotonation), the original emission color (yellow) comes back. Such reversible and also repeatable acidchromism is demonstrated to be perfectly suitable for anticounterfeiting applications by marking the AIEgen on the paper that shows the bright image of the AIEgen under the UV torch (365 nm). Almost equal efficiencies by fabricating on different surfaces such as polythene paper and a fresh leaf are observed. While these spots can be duplicated with typical yellow fluorescent dyes, our AIEgen can easily be differentiated with the acid key. The emission color change of this AIEgen from yellow to green under acid stimuli is distinctly defined compared to other dyes and vividly recognized by naked eyes. Thus, one can combat the counterfeiters with the acid key. The reversible color-changing behavior on the paper remains intact even after six consecutive days of exposure to sunlight, and the AIEgen is thermally stable up to 445 °C. Further, this compound is also utilized as ink (10 μM 1,4-dioxane solution) where a pigeon feather is used as a quill pen. The mechanistic insights behind these facts have also been proposed and validated wherever possible.

Synthesis and characterization of a novel, reactive, yellow fluorescent organosilicon dye and its polysiloxanes

A novel, reactive, yellow fluorescent organosilicon dye, N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide, is designed and synthesized and is used to fabricate a covalently yellow fluorescent silicone oil by polycondensation of hydroxy-terminated polydimethylsiloxane. The chemical structure and optical properties of the N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide and covalently yellow fluorescent silicone oil are characterized by 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, mass spectrometry, Fourier transform infrared, UV–Vis, and fluorescence spectra. The results indicate that the fluorescence quantum yields of N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide and covalently yellow fluorescent silicone oil are 2.61% and 3.5%, respectively. The λmax values of their dichloromethane solutions are 416 nm, and their λex and λem are 430 and 509 nm, respectively. Furthermore, covalently yellow fluorescent silicone rubbers are prepared using tetraethoxysilane as a cross-linker, and some of their properties are investigated. Thermogravimetric analysis and dynamic mechanical analysis show that heat resistance and tan δ of the covalently yellow fluorescent silicone rubber are improved in comparison with silicone rubbers without N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide moieties. Solvent extraction experiments indicate that the solvent resistance of the covalently yellow fluorescent silicone rubber is much better than that of noncovalently yellow fluorescent silicone rubber.

Synthesis and characterization of a novel, reactive, yellow fluorescent organosilicon dye and its polysiloxanes:

A novel, reactive, yellow fluorescent organosilicon dye, N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide, is designed and synthesized and is used to fabricate a covalently yellow flu...

Synthesis of yellow fluorescent dyes derived from benzoxanthene that can be used in colour converters for remote phosphor LED systems

The current commercially available yellow organic dyes are not stable enough to be used for remote phosphor LED applications. Therefore new yellow benzoxanthene dicarboximide dyes to convert blue light from LED into light of longer wavelengths were synthesized. The spectral properties of the dyes and their stability in PET films were examined. The compounds showed high photoluminescence quantum yield and above all superior photostability under operation conditions (10% reduction in photoluminescence at 450 nm irradiance of 0.016 W/cm2 at 60 °C). With extrapolated lifetimes up to 27000 h, a huge improvement in stability was established when compared to the commercially available yellow dyes exhibiting lifetimes lower than 1000 h.

Monitoring Fluorescence Colors to Separately Identify Cracks and Healed Cracks in Microcapsule-containing Self-healing Coating

We developed a system involving an extrinsic self-healing coating to identify cracked and healed regions by their yellow fluorescence and blue fluorescence, respectively. This system consisted of a top coating, an epoxy matrix resin containing a yellow fluorescent dye, and a microcapsule. This microcapsule in turn consisted of a healing agent, a blue aggregated-induced emitting luminogen, and a photo-initiator, as well as poly(urea-formaldehyde) as a shell material. Embedding the self-healing coating with a 25 mass% of microcapsules yielded the most efficient fluorescence detection and healing of the damaged region. Scratched and healed regions were successfully detected using our system under UV irradiation as well as under a one sun condition similar to sunlight. The blue fluorescence of the healed region was easily seen from 2m away.

Three dimensional visualization of solvent chamber growth during the VAPEX processes: An experimental approach using laser

VAPEX is a non-thermal process proposed as an alternative to SAGD due to its applicability in thinner reservoirs, advantage of energy efficiency, produced oil quality, and environmental saving. Its high cost caused by the injected solvent, however, requires further efforts to optimize the process. This, in turn, entails a clear understanding of the physics of the process. To acquire this understanding, a 3-D visualization technique was applied to a VAPEX model packed with glass beads. The oil saturated porous media and the solvent injected into the model processed refractive indices matched with the glass beads, which made the model transparent. Laser illuminated the yellow fluorescent dye dissolved in the solvent to distinguish it from the oil. Two high-speed cameras recorded the process from two sides of the model while a laser sheet moved along the model. A dome-shaped solvent chamber with viscous fingering on its top was observed. The injection pressure influenced the size of the chamber especially in the horizontal direction, which was not possible to identify through standard 2-D tests. Also, the solvent spread along the ceiling of the model and then displaced the oil down. The boundary of the solvent and oil was tilted and even curved at different injection rates. Finally, variable injection rate cases were compared with constant rate trials and an optimum operation plan was proposed through the analysis of the production rate, produced oil quality, and 3-D images of the chamber growth.

Study of Fluorescent Dyeing Process and Influence of Mixture Dyes on High-visibility

In this paper, we present the results of an investigation and analysis of an experimental study of fluorescent disperse dyes used for dyeing polyester fabrics to high-visibility colors. This paper describes the results of spectrophotometric color measurements for yellow luminous, red luminous and orange luminous fluorescent dyes and their matching with the requirements of the EN 471 standard. The results of this study showed that the adsorption isotherms of polyester dyeing with fluorescent disperse luminous dyes follow the Nernst equation; the Nernst constants were determined and interpreted. The adsorption kinetics of fluorescent disperse dyes on polyester is studied by using the peudo-first-order model, the pseudo-second-order equation and the intraparticle diffusion equation. The results show that pseudo-second-order models fit well the experimental data with higher average regression coefficients (R2> 0.98). They also show that high-visibility is influenced by the dye concentration, and that the dye mixtures can affect the high-visibility.

The impact of cleats on hydraulic fracture initiation and propagation in coal seams

Cleats are systematic, natural fractures in coal seams. They account for most of the permeability and much of the porosity of coalbed methane reservoirs and can have a significant effect on the success of hydraulic fracturing stimulation. Laboratory hydraulic fracturing experiments were conducted on coal blocks under true tri-axial stress to simulate fracturing stimulation of coal seams. Fractures were initiated by injecting a water gel with luminous yellow fluorescent dye into an open hole section of a wellbore. The impact of cleats on initiation and propagation of hydraulic fractures in coal seams is discussed. Three types of hydraulic fracture initiation and propagation pattern were observed in this study: 1) The hydraulic fracture initiated and then grew along the cleat. 2) The hydraulic fracture initiated along a butt cleat or a fracture (natural or induced by drilling) oriented roughly in the minimum horizontal stress direction, then turned to propagate along the first face cleat that it encountered or gradually turned towards the maximum horizontal stress direction. 3) The hydraulic fracture initiated perpendicular to the minimum stress and, when it encountered a face cleat, tended to propagate along the cleats if the extension direction does not deviate greatly (<20° as determined in this paper) from the maximum horizontal stress direction. When a coal seam is hydraulically fractured, the resulting fracture network is controlled by the combined effect of several factors: cleats determine the initiation and extension path of the fracture, the in-situ stress state dominates the main direction of the fracture zone and bedding planes impede fracture height growth.

Fluorescent Dye Conjugates of Rabbit Arylsulfatase A as a Biological Tracer for Protein Endocytosis

Fluorescent dye conjugates of arylsulfatase A (ASA) from rabbit liver were prepared at pH 9.0 in 0.1 M sodium bicarbonate buffer. The modification of amino or sulphadryl groups by dichlorotriazinylamino-fluorescein or Lucifer yellow fluorescent dyes did not alter the characteristic features of the enzyme molecule such as enzyme activity, dimerization of the protein molecule at pH 4.5 and anomalous kinetics of the native enzyme. The fluorescence intensity of the Lucifer yellow enzyme conjugates were quenched when the pH of the protein solution was changed from pH 7.5 to 4.5. Therefore, the Lucifer yellow enzyme conjugate can be used to study the kinetics of pH-dependent association and dissociation of the ASA. Availability of such fluorescent dyes conjugates of ASA or other lysosomal enzyme may be used as a biological tracer to study the receptor dependent endocytosis of enzyme molecules.

Energy Transfer Efficiency Control from the Blue Emitting Aromatics to the Yellow Fluorescent Intramolecular Charge Transfer Type Dye for Electroluminescence

An intramolecular charge transfer type yellow fluorescent material, (Z)-4-(2-[4,4″- bis(dimethylamino)-1,1′:4′,1″-terphenyl-2′-yl]-2′-1-cyanovinyl)benzonitrile (BDAT-CP) was synthesized for the implimentation to organic light emitting diodes (OLEDs). The molecules of the this catagory often have electro-conductivity and show high luminescence at longer wavelength in visible region. The BDAT-CP exhibited a large Stokes shift from 329 nm (UV absorption maximum) to 628 nm of photoluminescence(PL) in chloroform solvent. Solid powder PL showed yellow emission peaked at 582 nm. The device structures were indium tin oxide (ITO) / N,N′-bis-(1-naphyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB, 50 nm) / 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN, 30 nm): BDAT-CP (x %) / 4,7-diphenyl-1,10-phenanthroline (BPhen, 30 nm) / Liq(2 nm) / Al. The maximum luminance measured were 14700 cd/m2 (x = 5%), 9825 cd/m2 (x = 10%) and 7901 cd/m2 (x = 15%) for each BDAT-CP concentration. The luminance efficiency and quantum efficiency observed were 7.14 (x = 5%), 4.72 (x = 10%) and 3.19 (x = 15%), and 2.77 (x = 5%), 2.09 (x = 10%) and 1.59 (x = 15%), respectively. The device emitted yellow light corresponding to Commission Internationale de I’Eclairage (CIExy) coordinates of (0.492, 0.494) (x = 5%) and (0.523, 0.470) (x = 10%) and (0.545, 0.451) (x = 15%) at 8 V. This study showed that the energy transfer from MADN to BDAT-CP was dependent on the concentration of yellow dye, which affected the hole transporting properties of the OLED.

Laboratory investigation of triple marking the parasitoid Gonatocerus ashmeadi with a fluorescent dye and two animal proteins

AbstractGonatocerus ashmeadi Girault (Hymenoptera: Mymaridae), a parasitoid of Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) (glassy‐winged sharpshooter), was used as a model insect to investigate triple marking a minute hymenopteran for potential use for monitoring dispersal patterns of natural enemies in the field. The triple mark contained egg albumin in chicken eggs, casein in bovine milk, and SARDI yellow fluorescent dye. Three application treatments of the triple mark were investigated: (1) a wet topical treatment, (2) a dry residue treatment, and (3) untreated control. The presence of albumin and casein protein marks were detected by an anti‐albumin and anti‐casein enzyme‐linked immunosorbent assays (ELISA) using both ‘soaked’ and ‘crushed’ specimens. Of the topically treated parasitoids, yellow dye, casein, and albumin were detected on 88, 69, and 21% of the crushed samples, respectively. The yellow dye and casein (tested with crush ELISA) were the most efficient marking methods, detecting up to 29% more marked G. ashmeadi. Yellow dye resulted in zero false positives in the untreated control. The percentage of false positives for casein (tested with crush ELISA) was 1.3; however, this was reduced to 0% when a double‐marking system using any two of the three marks (yellow dye, casein, and albumin) were used to mark parasitoids. This double‐mark system resulted in 65% of parasitoids being successfully marked in the topical treatment over the duration of the study. For casein, crush ELISA was 26% more sensitive and 24% more accurate than soak ELISA for detecting this mark. Yellow dye, albumin, and casein (tested with crush ELISA) were retained on marked parasitoids for the entire duration of the 11‐day study. Parasitoids self‐marked with yellow dye, albumin (tested with soak ELISA), casein (tested with crush ELISA), and the double‐mark (tested with crush ELISA) by walking over dried residue of the triple mark. This resulted in up to 17% more marked parasitoids in the residue treatment compared with the untreated control. A topical application of the triple mark had no effect on survival of G. ashmeadi compared with the control. The residue treatment resulted in significantly lower mortality than the untreated control, indicating that G. ashmeadi may have fed on the protein in the residue of the triple‐mark, which enhanced longevity.

198 CILOSTAMIDE SUSTAINS GAP JUNCTION-MEDIATED COMMUNICATION AND CHROMATIN REMODELLING IN PIG OOCYTES

In the pig, the efficiency of in vitro embryo production procedures is still limited. It has been suggested that prematuration treatments could improve the developmental capability of oocytes. In particular, recent studies conducted in the bovine (Luciano, 2011, BOR, in press) indicate that the prolongation of a patent bidirectional crosstalk between the oocyte and the surrounding cumulus cells, together with the maintenance of a proper level of cAMP during the prematuration culture, could be beneficial to oocytes that have not yet acquired full meiotic and developmental capability. The aim of the present study was to assess the effect of treatment with cilostamide, an inhibitor of the phosphodiesterase 3 (PDE3), which degrades cAMP, on the functional status of gap junction-mediated communication (GJC) in pig cumulus–oocyte complexes (COC). Moreover, since chromatin configuration represents a marker of oocyte differentiation and competence, the effect of cilostamide on the process of chromatin remodeling was also evaluated during the culture period. To this aim, COC were collected from 3- to 6-mm antral follicles and cultured for up to 24 h in defined culture medium supplemented with 0.1 IU mL–1 of FSH in the presence or absence of 1 μM cilostamide. The GJC functionality was assessed by Lucifer Yellow fluorescent dye microinjection at the time of collection (0 h) and after 12, 18, or 24 h of culture. Chromatin configuration was evaluated by fluorescence microscopy after removal of cumulus cells and DNA staining with Hoechst and oocytes were classified according to Bui et al. (2004 BOR 70, 1843–1851) as SC, (with stringy chromatin within the germinal vesicle), GVI (with chromatin condensed in a rim around the nucleolus), GVII-IV (where the beginning of formation of chromatin strands is typical), ProMI (prometaphase I) and MI (metaphase I). The administration of cilostamide sustained functional coupling for up to 24 h of culture as the percentage of COC with open GJC was significantly higher when compared with the control group (62.2% vs 30%; P &lt; 0.05) and not significantly different from the time 0 h (80%). The maintenance of the coupling during the culture period was accompanied by a delay of the meiotic resumption as only 26.3% of cilostamide-treated oocytes underwent germinal-vesicle breakdown and reached ProMI stage compared to the control group (62.1%; P &lt; 0.05). Moreover the transition towards advanced stages of differentiation, as judged by the chromatin configuration, was slowed down in the presence of cilostamide. In conclusion, our study indicates that the maintenance of elevated cAMP levels through the inhibition of PDE3 sustains a functional bidirectional communication between the oocyte and cumulus cells and delays meiotic resumption in the pig oocyte. This could be a useful approach for the development of prematuration treatments aimed at improving the embryonic developmental potential of pig oocytes. Experiments are in progress in our laboratories to confirm this hypothesis. This study has been supported by EU FP6 grant n LSHB-CT-2006-037377 (Xenome) EU FP7- n°223485 (Plurisys).

꽃게 통발용 미끼 및 미끼통의 형광 특성

In order to develop the substitutive materials for natural baits of swimming crab pots, the fluorescent characteristics of the baits were analyzed, and the preference of fluorescent dyes were investigated by the mean entrapped catch number to the pots through the water tank experiments and fishing experiments. On the investigation of fluorescent characteristics by the 5 kinds of baits, mackerel, krill, manila clam, pig's fat and chicken's head which were used in substitutive baits for test in the UV long wave(365nm) area, it showed clear blue fluorescence in the skin of mackerel, shell of krill, manila clam and bill of chicken's head, and green fluorescence in the mackerel s muscle and internals, and yellow fluorescence in the pig's fat and chicken's head. On the investigation of fluorescent characteristics by the bait cages in the UV short wave(254nm) and long wave(365nm) area, it showed each green, red and blue fluorescence in the cylinderical or hexahedral red plastic bait cages which were painted each green, red and blue fluorescence dyes, but it showed yellowish green flourescence in the cylinderical or hexahedral red plastic bait cage which was painted yellow fluorescent dye. On the preference investigation of the fluorescent dyes of swimming crabs by the 5 kinds of the bait cages which were put the mackerel in the non-fluorescent red plastic cage(<TEX>$RF_N$</TEX>), red, yellow, green and blue fluorescent plastic cages(RF, YF, GF, BF) each, nonfluorescent red plastic cage(<TEX>$RF_N$</TEX>) was entrapped mean 2.0(6.7%), but blue fluorescent plastic cage(BF) was mean 5.0(16.7%) and it was more 2.5 times comparing to <TEX>$RF_N$</TEX>, and red fluorescent cage(RF) was same level and green fluorescent cage(GF) was 50% of catch number comparing to <TEX>$RF_N$</TEX>, and yellow fluorescent cage(YF) was entrapped nothing(F 46.324, P < 0.05). On the investigation of the entrapped catch number to the pots which were put the mackerel in the blue fluorescent hexahedral plastic cage(HP) and blue fluorescent silicon mackerel model cage(SM), HP was mean 3.4(11.3%) and it was a little more comparing to SM which was entrapped mean 3.2(10.7%)(t 0.775, P > 0.05). Fishing experiments on the preference investigation of swimming crabs by the pots which were put in the non-fluorescent red plastic cage(<TEX>$RF_N$</TEX>) and blue fluorescent plastic cage(BF) were conducted 3 times. Mean catching number and weight of <TEX>$RF_N$</TEX> were 71.7 ind.(18.3%) and 16.9kg(64.3%), and those of BF were 93.0 ind.(23.1%) and 19.8kg(64.5%), respectively.

350 EFFECT OF INDIRECT MAINTENANCE OF INTRACELLULAR cAMP IN CUMULUS - OOCYTE COMPLEXES USING 3-ISOBUTYL-1-METHYLXANTHINE ON GAP JUNCTIONAL COMMUNICATIONS AND OOCYTE MEIOTIC MATURATION

Oocyte and cumulus cells communicate through an extensive network of gap junctions (GJs), which permit the transfer of small molecules such as cAMP. Gonadotropin strongly enhances the intracellular cAMP concentration in cumulus cells, and induces oocyte meiotic resumption. Enhanced cAMP also triggers a reduction of GJ communications (GJCs) in cumulus-oocyte complexes (COCs), accompanied by cumulus expansion. Intracellular cAMP is modulated by both adenylate cyclase (AC) for synthesizing and phosphodiesterase (PDE) for degrading. Addition of AC to gonadotropin-free medium induces meiotic resumption of bovine oocytes without cumulus expansion, suggesting that maintenance of cAMP at a certain level in COCs may be crucial for either prolonged maintenance of GJCs or the timing of oocyte meiotic resumption. In the present study, we investigated the intracellular cAMP concentrations in porcine COCs or oocytes, and GJCs during in vitro oocyte maturation culture using PDE inhibitor 3-isobutyl-1-methylxanthine (IBMX). Porcine COCs obtained from prepubertal gilts were cultured for 20 h (1st culture) using M199 containing 10% FCS (basic medium, BM group) with FSH (FSH group) or IBMX (IBMX group). Following this, the COCs were transferred into the basic medium containing FSH and LH, and cultured for another 24 h (2nd culture). At 6, 12, and 20 h of the 1st culture, intracellular cAMP in COCs or oocytes was measured. To determine GJCs in each COC, Lucifer Yellow fluorescent dye was microinjected into cumulus-enclosed oocytes at 6 or 12 h of the 1st culture, and the ability of dye transfer, which is related to the GJCs, from the oocyte to the surrounding cumulus cells was observed. At the end of the 1st culture, 30.8 � 6.0% of the oocytes in the FSH group underwent germinal vesicle breakdown (GVBD), whereas only a few oocytes in the BM group (8.6 � 2.4%) and the IBMX group (5.8 � 3.0%) achieved GVBD (P &amp;lt; 0.05). In contrast, ratios of metaphase-II (M-II) stage oocytes at the end of the 2nd culture did not differ between the FSH group (75.7 � 3.9%) and the IBMX group (68.2 � 6.8%), although a few oocytes in BM group (10.1 � 3.7%) reached the M-II stage (P &amp;lt; 0.05). Concentrations of cAMP in COCs and oocytes increased drastically in the FSH group compared to those of the BM and IBMX groups (P &amp;lt; 0.05). In addition, the concentration of cAMP in IBMX group oocytes was also higher than that in the BM group, with a significant difference detected at 20 h (P &amp;lt; 0.05). The GJCs in the FSH group were gradually closed, depending on the length of time in culture (54.9 � 3.7% of COCs closed their GCJs at 12 h of the 1st culture). In contrast, in the IBMX group, only 23.0 � 3.7% of COCs closed their GJCs at 12 h of the 1st culture, which was significantly different from that of the other two groups (P &amp;lt; 0.05). These results suggest that treatment with IBMX during the first half of IVM culture can induce subsequent meiotic resumption of porcine oocytes, and that a moderate increase of cAMP concentration in COCs or oocytes prolongs GJCs during the treatment.

Efficient white organic light-emitting device based on a thin layer of hole-transporting host with rubrene dopant

A white organic light-emitting device (WOLED) in which a yellow fluorescent dye, rubrene (5,6,11,12-tetraphenylnaphthacene), is doped into a thin layer of traditional hole-transporting material NPB {4,4′-bis[ N-(1-naphthyl)- N-phenylamino]biphenyl} is fabricated. The device has a simple structure of indium tin oxide (ITO)/CuPc/NPB/NPB: 0.7 wt.% rubrene/TPBI/lithium fluoride (LiF)/Al, where CuPc (copper phthalocyanine) and TPBI {2,2′,2″-(1,3,5-benzenetriyl)tris[1-phenyl-1 H-benzimidazole]} are used as the hole-injecting layer and electron-transporting and hole-blocking layer, respectively. The device exhibits peak efficiency of 3.7 cd/A (2.1 lm/W) at 5.5 V and maximum brightness of 8200 cd/m 2 at 20 V. The Commission Internationale de l’Eclairage (CIE) coordinates of (0.291, 0.303) are determined at 6 V. When the bias increased from 6 V to 14 V, the colour coordinates shifted only by ∼2%, which is presumably related closely to the thickness of the doped NPB layer. Besides, the electroluminescent (EL) efficiency can also be improved by decreasing the thickness of the doped NPB layer. The mechanisms of generating stable white colour and improving EL performances are also discussed.

Sensitization Effects of Fluorescent Dichroic Dyes in a Nematic Liquid Crystal and Fluorescence Colors

ABSTRACT In a nematic liquid crystal (LC), the excitation energy of an ultraviolet light (360 nm) is efficiently transferred to yellow fluorescent dye via blue fluorescent sensitizer, to enhance yellow fluorescence of the dichroic dye. The LC can emit white fluorescence when yellow and blue fluorescent dyes are mixed at suitable concentrations. In the homogeneously aligned cell with the fluorescent nematic LC, fluorescent dye molecules reorient along the applied electric field with LC molecules when the voltage is applied to the LC cell. With the increase of the voltage, the fluorescent intensity decreases without changing the fluorescent color. The contrast ratio at 0 and 8 V is about 6.5.

GCV phosphates are transferred between HeLa cells despite lack of bystander cytotoxicity

The role of gap junctional intercellular communication (GJIC) in bystander killing with herpes simplex virus thymidine kinase (HSV-TK) and ganciclovir (GCV) was evaluated in U251 cells expressing a dominant-negative connexin 43 cDNA (DN14), and in HeLa cells, reportedly devoid of connexin protein. These cell lines both exhibited 0% GJIC when assayed by Lucifer Yellow fluorescent dye microinjection. Bystander cytotoxicity was still apparent in 50:50 cocultures of DN14 and HSV-TK-expressing U251 cells, but not in 50:50 cocultures of HeLa cells. However, the sensitivity of HeLa HSV-TK-expressing cells to GCV decreased nearly 100-fold (IC90=109 microM) when cocultured with bystander cells compared to results in 100% cultures of HSV-TK-expressing cells (IC90=1.2 microM). A more sensitive flow cytometry technique to measure GJIC over 24 h revealed that the DN14 and HeLa cells exhibited detectable levels of communication (29 and 23%, respectively). Transfer of phosphorylated GCV to HeLa bystander cells occurred within 4 h after drug addition, and GCV triphosphate (GCVTP) accumulated to 213+/-84 pmol/10(6) cells after 24 h. In addition, GCVTP levels were decreased in HSV-TK-expressing cells in coculture (867+/-33 pmol/10(6) cells) compared to 100% cultures of HSV-TK-expressing cells (1773+/-188 pmol/10(6) cells). The half-life of GCVTP in the HSV-TK-expressing cells was approximately four times that measured in the bystander cells (12.3 and 3.1 h, respectively). These data suggest that the lack of bystander cytotoxicity in HeLa cocultures is due to low transfer of phosphorylated GCV and a rapid half-life of GCVTP in the bystander cells. Thus, GCV phosphate transfer to non-HSV-TK-expressing bystander cells may mediate either bystander cell killing or sparing of HSV-TK-positive cells, depending upon the cell specific drug metabolism.

Role of intracellular cyclic adenosine 3',5'-monophosphate concentration and oocyte-cumulus cells communications on the acquisition of the developmental competence during in vitro maturation of bovine oocyte.

The present study was designed to address the physiological role played by cAMP on gap junction (GJ) mediated communications between oocyte and cumulus cells during in vitro maturation. Cyclic AMP was stimulated by different collection and maturation media known to induce different rates of nuclear maturation and developmental competence as well as different levels of cumulus expansion. Cumulus-oocyte complexes (COCs) were matured for 0, 3, 7, 12, 18, and 24 h in the absence of stimulation or in the presence of serum and gonadotropins (fetal bovine serum+human menopausal gonadotropins [FCS+hMG]) or 0.01 microg/ml of invasive adenylate cyclase (iAC). For each time point, intracellular cAMP concentration ([cAMP]i) was determined either in the whole COC or oocyte after cumulus cell removal. GJ functional status was analyzed by microinjection of Lucifer yellow fluorescent dye in cumulus-enclosed oocytes and by immunohistochemical localization of connexin 43 (Cx43). In the absence of stimulation, [cAMP]i in COC and oocyte was lower than in other groups, and communications declined after 3 h of culture. In the FCS+hMG group, [cAMP]i increased significantly in COC, with a peak between 3 and 7 h that was temporally correlated with the beginning of the cumulus expansion process, which occurred only in this group and with the termination of the communications. COC matured in the presence of iAC showed a moderate increase of [cAMP]i during all of the maturation times as well as a prolongation of oocyte-cumulus cell communications. The immunohistochemical localization of Cx43 confirmed the delay in connexons protein turnover in iAC-treated COCs. Our results show that cumulus expansion and oocyte developmental competence are induced by different levels of cAMP and that its intracellular concentration may affect cell coupling between oocyte and cumulus cells. We hypothesize that the higher developmental competence of COCs matured in the presence of iAC could be achieved through a moderate increase of intracellular cAMP, which in turn determines a prolongation of communications between the two cell types.

Physiological levels of melatonin enhance gap junction communication in primary cultures of mouse hepatocytes.

Gap junction communication is known to be involved in controlling cell proliferation and differentiation, and seems to play a crucial role in suppression of tumor promotion. Melatonin, a hormone secreted by the pineal gland, has putative oncostatic properties. Intercellular communication through gap junctions was assessed by microinjecting Lucifer yellow fluorescent dye into primary hepatocytes and visualizing the spread of the dye to adjacent neighboring cells using phase contrast/fluorescent microscopy. Treatment of primary hepatocyte cultures with a physiological range of melatonin concentrations for 24 h prior to microinjection resulted in significant enhancement in intercellular communication at 0.2 and 0.4 nmol/L but not at lower (0.1 nmol/L) or higher (0.8 or 1.0 nmol/L) concentrations. A time-dependent study showed that the changes in intercellular communication began 10 h after melatonin treatment and reached a maximum at 12 h of treatment. This nonlinear, functional gap junction response to melatonin occurred in the physiological concentration range detected in blood of mammals during nightly releases of the hormone by the pineal gland. These melatonin levels may affect the ability of gap junction communication to exert cell growth control in vivo. The uneven decline between individuals in nocturnal release of melatonin that occurs with age could identify potentially sensitive subpopulations susceptible to developing pathologies involving alterations in biological processes dependent on gap junction communication.