H2O Fractions Research Articles

Experimental analysis of CO/H2 syngas with NOx and SOx reactions in pressurized oxy-fuel combustion

A pressurized oxy-fuel combustion system is a technology for carbon capture and storage with a low efficiency penalty. In this study, the characteristics of combustion, heat transfer, and NOx/SOx emissions at various pressures were investigated using a lab-scale pressurized oxy-fuel combustion system. A gaseous fuel, composed of CO and H2, and pure oxygen were considered. The internal flue gas recirculation was induced by the inner wall to control the high oxy-flame temperature. The total heat recovery rate determined using the water jacket is 3% higher at 10 barg compared with atmospheric conditions, although the combustion temperature is lower. The heat flow rate increased by a higher H2O fraction in flue gas because the emissivity of H2O is higher than that of CO2. Under the condition of low H2O in flue gas, NOx and SOx simultaneously decreased, by approximately 50% and 63% at 10 barg, respectively. The concentrations of NOx and SOx with a higher H2O contents condition in flue gas decreased by 87% and 93% respectively at 10 barg, compared with atmospheric conditions. The effects of H radicals and the H2O fraction on the NOx and SOx oxidation and decrease were identified.

Anti-Influenza Activity of an Ethyl Acetate Fraction of a Rhus verniciflua Ethanol Extract by Neuraminidase Inhibition.

Antigenic mismatch can cause influenza vaccines to be ineffective, and influenza viruses resistant to antiviral drugs are rising. Thus, development of antiviral agents against these viruses is an immediate need. Rhus verniciflua (RVS) has long been used in herbal medicine and as a nutritional supplement. The effect of RVS and its components on influenza virus has not, however, been reported. We found that RVS treatment significantly reduced viral replication when evaluated with green fluorescent protein- (GFP-) tagged virus (influenza A virus, A/PR/8/34-GFP) in Madin–Darby canine kidney (MDCK) cells. RVS showed significant inhibition of neuraminidase from A/PR/8/34. Subsequently, three fractions were prepared from an ethanolic crude extract of RVS. In vitro assays indicated that an ethyl acetate fraction (RVSE) was more potent than H2O and CHCl3 fractions. RVSE significantly suppressed influenza virus infection in MDCK cells via neuraminidase inhibition. Additionally, RVSE treatment inhibited expression of several virus proteins and decreased mortality of mice exposed to influenza A/PR/8/34 by 50% and reduced weight loss by 11.5%. Active components in RVSE were isolated, and 5-deoxyluteolin (5) and sulfuretin (7) demonstrate the highest neuraminidase inhibitory activity against influenza A virus. RVS, RVSE, and their constituents may be useful for the development of anti-influenza agents.

A priori DNS study of applicability of flamelet concept to predicting mean concentrations of species in turbulent premixed flames at various Karlovitz numbers

Complex-chemistry direct numerical simulation (DNS) data obtained earlier from lean hydrogen-air flames associated with corrugated flame (case A), thin reaction zone (case B), and broken reaction zone (case C) regimes of turbulent burning are analysed to directly assess capabilities of the flamelet approach to predict mean concentrations of species in a premixed turbulent flame. The approach consists in averaging dependencies of mole fractions, reaction rates, temperature, and density on a single combustion progress variable c, which are all obtained from the unperturbed laminar flame. For this purpose, four alternative definitions of c are probed and two probability density functions (PDFs) are adopted, i.e. either an actual PDF extracted directly from the DNS data or a presumed β-function PDF obtained using the DNS data on the first two moments of the c(x, t)-field. Results show that the mean density and mean mole fractions of H2, O2, and H2O are well predicted using both PDFs for each c, although the predictive capabilities are little worse in case C. In cases A and B, the use of the actual PDF and the fuel-based c also offers an opportunity to well predict mean mole fractions of O and H, whereas the mean mole fraction of OH is slightly underestimated. In the highly turbulent case C, the same approach performs worse, but still appears to be acceptable for evaluating the mean radical concentrations. The use of the β-function PDFs or another combustion progress variable yields substantially worse results for these radicals. When compared to the mean mole fractions, the mean rate of product creation, i.e. the source term in the transport equation for the mean combustion progress variable, is worse predicted even for a quantity (species concentration or temperature) adopted to define c and using the actual PDF. Consequently, turbulent burning velocity is not predicted either.

Experimental Study of EGR Dilution and O2 Enrichment Effects on Turbulent Non-Premixed Swirling Flames

ABSTRACT This paper presents experimental results of the effects of CO2 and H2O dilution on CH4-air flames enriched by oxygen. The study focuses on pollutant emissions, flame stability through the determination of liftoff heights and flow fields by LDV measurements. Different parameters of the burner are studied such as the swirl number, the global equivalence ratio, and the fractions of O2, H2O, and CO2 in the mixture. The fraction of diluents varies from 0% to 20%, O2 enrichment from 21% to 30% (in vol.), and the swirl number from 0.8 to 1.4. The experiments are carried out on a coaxial swirled burner placed in a vertical combustion chamber. The flame is visualized by the chemiluminescence technique on OH* in order to locate the flame front. Measurements of combustion products such as NOx, CO, and CO2 are done using a HORIBA PG250 multi-gas analyzer. Flow fields are measured by LDV measurement for the longitudinal velocity component and its fluctuations. Results show that the CO2 and H2O dilution influences significantly the flame characteristics. With dilution the liftoff height increases but the flame remains stabilized. With O2 enrichment the liftoff height decreases and flame stability is enhanced. If we therefore want to dilute more, we should enrich with oxygen. The increase of dilution rate induces a decrease in NOx emission and exhaust gas temperature and an increase in CO emissions. LDV measurements showed the longitudinal velocity distribution of flow and its fluctuations in reactive and non-reactive conditions. Note that the presence of the flame induces an increase in the longitudinal velocity downstream of the flow due to the expansion of gases.

Aggregation-Induced Electrochemiluminescence of the Dichlorobis(1,10-phenanthroline)ruthenium(II) (Ru(phen)2Cl2)/Tri-n-propylamine (TPrA) System in H2O–MeCN Mixtures for Identification of Nucleic Acids

Aggregation-induced electrochemiluminescence (AIECL) of the dichlorobis(1,10-phenanthroline)ruthenium(II) (Ru(phen)2Cl2)/tri-n-propylamine (TPrA) system was systematically investigated in H2O-MeCN media. Up to a 120-fold increase in the ECL intensity was observed when the H2O fraction (v%) was changed from 30% to 70%, whereas only an approximately 5.7-fold increase in the corresponding aggregation-induced fluorescence emission was demonstrated. The gradual formation of clusters of Ru(phen)2Cl2 nanoaggregates along with the increase in the H2O fraction to MeCN, which was verified by dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), was believed to be responsible for the remarkable ECL enhancement. Significantly, the above-mentioned AIECL behavior was found to be very sensitive to the types and sequences of nucleic acids present in solution, which provided an effective and novel strategy for distinguishing RNA from DNA and for differentiating different miRNAs. The present study could have a substantial impact in various research areas, such as molecular sensors, bioimaging probes, organelle-specific imaging, and tumor diagnosis.

Surface density function evolution and the influence of strain rates during turbulent boundary layer flashback of hydrogen-rich premixed combustion

The statistical behavior of the magnitude of the reaction progress variable gradient [alternatively known as the surface density function (SDF)] and the strain rates, which govern the evolution of the SDF, have been analyzed for boundary layer flashback of a premixed hydrogen-air flame with an equivalence ratio of 1.5 in a fully developed turbulent channel flow. The non-reacting part of the channel flow is representative of the friction velocity based Reynolds number Reτ = 120. A skeletal chemical mechanism with nine chemical species and twenty reactions is employed to represent hydrogen-air combustion. Three definitions of the reaction progress variable (RPV) based on the mass fractions of H2, O2, and H2O have been considered to analyze the SDF statistics. It is found that the mean variations of the SDF and the displacement speed Sd depend on the choice of the RPV and the distance away from the wall. The preferential alignment of the RPV gradient with the most extensive principal strain rate strengthens with an increase in distance from the cold wall, which leads to changes in the behaviors of normal and tangential strain rates from the vicinity of the wall toward the middle of the channel. The differences in displacement speed statistics for different choices of the RPV and the wall distance affect the behaviors of the normal strain rate due to flame propagation and curvature stretch. The relative thickening/thinning of the reaction layers of the major species has been explained in terms of the statistics of the effective normal strain rate experienced by the progress variable isosurfaces for different wall distances and choices of RPVs.

PALYNOLOGICAL ORIGIN, PHENOLIC CONTENT AND ANTIOXIDANT PROPERTIES OF GEOPROPOLIS COLLECTED BY MANDAÇAIA (MELIPONA MANDACAIA) STINGLESS

ABSTRACT The stingless bee Melipona mandacaia (Smith 1863) (mandaçaia) is found only in the region of Caatinga, Northeastern Brazil, in the states of Bahia and Pernambuco, near to São Francisco river. The aim of the present work was to determine the botanical origin and to evaluate the phenolic content and antioxidant properties (β-carotene/linoleic acid system, DPPH and ABTS scavenging) of mandaçaia geopropolis. 25 pollen types from 15 families were identified from the 9 geopropolis samples analyzed. Phenolic compounds content varied between all the geopropolis EtOH extracts, hexane, EtOAc and MeOH:H2O fractions. The main pollens found in the geopropolis samples were from the Leguminoseae family. This identification of meliponicultural plants is extremely important because it indicates the food sources used for the collection of nectar and pollen. Our results revealed that there is a strong relation between the phenolic compounds and the antioxidant activity. These results showed that total phenols of mandaçaia geopropolis may be responsible for the antioxidant activity with evidence that it's a rich source of phenols bioactive compounds with potential health benefits.

Mixture rules and falloff are now major uncertainties in experimentally derived rate parameters for H + O2 (+M) ↔ HO2 (+M)

Rate constants for the title reaction for different bath gas species, M, are essential to accurate combustion predictions. Most experimental studies of the title reaction assume the reaction is in the low-pressure limit. Furthermore, experimental studies for M = H2O usually rely on measurements in H2O/A mixtures, separate measurements in a reference bath gas M = A, and an assumed mixture “rule,” which estimates rate constants in the mixture from those of pure bath gases. We present results from master equation calculations to quantify the uncertainties due to these assumptions in experimental interpretations. Our calculations indicate potential errors due to falloff and mixture rule assumptions that would be imperceptible experimentally over typical variations of pressure and composition yet introduce substantial uncertainties (reaching ∼ 50%) in reported rate constants, which often involve extrapolation to zero pressure and unity mole fraction. Going forward, we recommend that experimentally determined pseudo-second-order rate constants for H + O2 ↔ HO2 for the experimental pressure and mixture composition (which are independent of these assumptions) be reported, that experiments used to derive rate constants in the low-pressure limit or for M = H2O be conducted at lower pressures and higher H2O fractions (where these assumptions are more accurate), and that uncertainty analysis consider uncertainties due to falloff and mixture rule assumptions.

Anwulignan from the fruits of Schisandra chinensis and its cytotoxicity against human cancer cell lines

Background: The fruits of Schisandra chinensis have been used traditionally as the medicinal materials in East Asia. Their extracts have been reported to be cytotoxic to several cancer cells and phytochemical research has identified numerous cytotoxic lignans. Objectives: We reviewed for the effects of cytotoxic lignans against various human cancer cells. Materials and Methods: Solvent extraction of fruits in aqueous methanol and fractionation of the extract into H2O, n-BuOH, and EtOAc fractions (Fr) were carried out. Column chromatography (CC) of the non-polar EtOAc Fr, which indicated cytotoxicity to cancer cells, was performed to isolate the cytotoxic lignin. They were identified on the basis of the intensive spectroscopic interpretation of IR, 1D-, 2D-NMR, and mass spectrometry data. The cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and cell staining using Hoechst 32258 and propidium iodide. Results: Anwulignan was isolated and identified as a cytotoxic principal component. The IC50 value was calculated to be 22.01 ± 1.87, 156.04 ± 6.71, and 32.68 ± 2.21 μM for human stomach adenocarcinoma, human colon cancer (HT29), and human cervical cancer cells, respectively. Conclusion: Solvent extraction, systematic fractionation, and repeated CC for S. chinensis fruits led to the isolation of a lignin identified to be anwulignan based on various spectroscopic analyses. Anwulignan demonstrated very high cytotoxicity to most human cancer cell lines, and cell death was induced by apoptosis.

Anti-MMP-2 and MMP-9 activity of Salsola komarovii Iljin extract and its solvent fractions

Objective: To investigate matrix metalloproteinases (MMP)-2 and MMP-9 inhibitory effect of Salsola komarovii Iljin, an edible halophyte with health beneficial effects. Methods: Salsola komarovii crude extracts (SKI), and solvent (n-hexane, 85% aq. MeOH, n-BuOH, and H2O) fractionated extracts of SKI were prepared. Gelatin zymography was carried out to observe MMP enzymatic activity. The release of the MMP enzymes was measured by enzyme-linked immunosorbent assay. Expression of MMPs in mRNA and protein level were investigated by polymerase chain reaction analysis and immunoblotting, respectively. Results: SKI and SKI fractions inhibited active MMP-2 and MMP-9 amount in the treated cell culture medium. Also, SKI suppressed the release of MMP-2 and MMP-9 from stimulated HT1080 human fibrosarcoma cells. Furthermore, SKI suppressed the mRNA and protein expression of MMP-2 and MMP-9. SKI fractions showed parallel effects except for H2O fraction which did not yield any significant MMP inhibitory effect. Among fractions, 85% aq. MeOH was the most active fraction to inhibit both the enzymatic effect and expression of MMP-2 and MMP-9. Conclusions: SKI may contain potential MMP release inhibitory compounds. Salsola komarovii is a promising source of compounds against MMP and could be utilized in the development of antitumor agents.

CFD simulation of the steam gasification of millimeter-sized char particle using thermally thick treatment

A detailed char gasification model is developed using a multiphase Eulerian–Lagrangian algorithm and thermally thick treatment. The model is first validated by both gasification and combustion experiments of a millimeter-sized char particle. Temperature and mass loss histories as well as the particle morphology evolution correspond well with the existing results. Then the steam gasification of a 5 mm char particle is simulated and detailed physical and chemical conversion processes inside the particle are explored. During gasification, three distinct layers, i.e., the outer ash layer, the intermediate layer and the core layer, are identified based on the intraparticle porosity distribution. Simulation results show that the highest H2O and CO2 mass fractions locate in the ash layer, while the intermediate and core layers contain the highest H2 and CO mass fractions, respectively. Moreover, effects of several parameters are also explored. It is found that the Stefan flow caused by the mass transfer plays a key role in determining the diffusion and convection behavior during gasification. The strength of the Stefan flow in the intermediate layer appears to be two orders of magnitude smaller than that of the inflow and has an influence on the shifting from a kinetically-controlled mode to a diffusion-controlled mode. In addition, the char consumption rate in the intermediate layer increases with an increase in steam mass fraction, gasification temperature and inflow velocity while it decreases with increasing particle diameter. Meanwhile, the char consumption rate caused by CO2 is much smaller than that due to steam.

Molecular dynamics simulation and theoretical study on heat capacities of supercritical H2O/CO2 mixtures

Molecular dynamics (MD) simulations and calculations based on the Peng-Robinson equation of state (PR-EOS) are carried out to compute the heat capacities of pure H2O and CO2 and supercritical H2O/CO2 mixtures. Using NIST data as a reference, it is found that the two methods generally exhibit comparable and acceptable performance in prediction of the heat capacities of the supercritical fluids. However, in near-critical region for pure supercritical H2O and the supercritical H2O/CO2 mixtures at higher mole fractions of H2O, PR-EOS exhibit poor prediction accuracy while MD simulation models achieve much better performance. The radial distribution function (RDF) and hydrogen bond analysis shows that this should contribute to the ability of MD simulations to deal with the effect of hydrogen bonding. This work is helpful for guiding the future investigation of the heat capacity of other working mixtures in thermodynamic systems based on the supercritical water gasification of coal.

Flavonoids from Chionanthus retusus (Oleaceae) Flowers and Their Protective Effects against Glutamate-Induced Cell Toxicity in HT22 Cells.

The dried flowers of Chionanthus retusus were extracted with 80% MeOH, and the concentrate was divided into EtOAc, n-BuOH, and H2O fractions. Repeated SiO2, octadecyl SiO2 (ODS), and Sephadex LH-20 column chromatography of the EtOAc fraction led to the isolation of four flavonols (1–4), three flavones (5–7), four flavanonols (8–11), and one flavanone (12), which were identified based on extensive analysis of various spectroscopic data. Flavonoids 4–6 and 8–11 were isolated from the flowers of C. retusus for the first time in this study. Flavonoids 1, 2, 5, 6, 8, and 10–12 significantly inhibited NO production in RAW 264.7 cells stimulated by lipopolysaccharide (LPS) and glutamate-induced cell toxicity and effectively increased HO-1 protein expression in mouse hippocampal HT22 cells. Flavonoids with significant neuroprotective activity were also found to recover oxidative-stress-induced cell damage by increasing HO-1 protein expression. This article demonstrates that flavonoids from C. retusus flowers have significant potential as therapeutic materials in inflammation and neurodisease.

Supramolecular nanomaterials with photocatalytic activity obtained via self-assembly of a fluorinated porphyrin derivative

Porphyrin aggregates formed via self-assembly have shown promising photocatalytic activity due to the combination of their optical and morphological properties. The structural and physical properties of porphyrin affect its self-assembly and the properties of the resulting aggregates. The hydrophobicity/hydrophilicity of the porphyrins in solvent mixtures, which affect self-assembly, can be altered by the introduction of fluorine groups. In this work, we report the synthesis of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TPFPP). The differing solubilities of TPFPP in organic and aqueous solutions were exploited to promote the self-assembly of monomeric TPFPP in THF/H2O solvent mixtures. The effect of the H2O fraction on the assembly process and resulting morphologies was probed using UV–vis spectroscopy, photoluminescence spectroscopy, and scanning electron microscopy (SEM). It was observed that well-defined TPFPP microrods with a diameter of 1–3 µm and length of 20–100 µm as well as octahedral crystals 30 µm in size were produced with H2O fractions of 70 and 80%, respectively. These TPFPP aggregates with controlled morphologies exhibited high photocatalytic activity, evident in photocatalytic degradation studies with rhodamine B (RhB) which degraded under visible light irradiation with rate constants of 3.76 × 10−3 (with microrods) and 2.93 × 10−3 min−1 (with octahedral crystals). A possible mechanism for the photocatalytic activity of the TPFPP aggregates for RhB degradation was proposed.

Alcohol and alkane fuel performance for Gas Generator cycle Air Turbo Ramjet Engine

The present study investigates the feasibility of alcohol fuels for a Gas Generator cycle Air Turbo Ramjet (GG-ATR) Engine in comparison with alkane fuels. The alkane and alcohol fuels in the present study range from C1 species (CH4 and CH3OH) to C4 species (n-C4H10 and 1-C4H9OH).The present study analytically evaluates Specific thrust and Specific impulse (Isp) of GG-ATR engine as functions of gas generator combustion temperature. For both alcohols and alkanes, the peak Gas Generator (GG) combustion temperatures exist for specific thrust and ram combustor temperature. Comparing alcohol to alkane in the lower GG combustion temperature, specific thrusts and Isp of alcohol tend to be higher than those of C2H6, C3H8, and 1-C4H10. GG combustion gases for alcohol fuels contain higher mole fractions of H2O and CO2 than those for alkanes. Because of high mole fractions of H2O and CO2, the ratio of GG combustion gas for alcohols to air flow rate is fortunately close to the stoichiometric ratio, resulting in higher ram combustion temperature. The high ram combustion temperature can contribute to the higher specific thrust and Isp. Lower GG combustion temperature is preferable because of a thermal limit of a turbine blade. Thus, alcohols have superiorities to alkanes for the GG-ATR engine application.

6-Methoxyflavonols from the aerial parts of Tetragonia tetragonoides (Pall.) Kuntze and their anti-inflammatory activity

Dried aerial parts of Tetragonia tetragonoides were extracted with 70% EtOH, and the evaporated residue was successively separated into EtOAc, n-BuOH, and H2O fractions. As a result of repeated SiO2, ODS, and Sephadex LH-20 column chromatography, four new 6-methoxyflavonol glycosides (2–4, 8) along with four known ones (1, 5–7) were isolated. Several spectroscopic data led to determination of chemical structures for four new 6-methoxyflavonol glycosides (2–4, 8) and four known ones, 6-methoxykaempferol 3-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranosyl-7-O-(6‴′-(E)-caffeoyl)-β-d-glucopyranoside (1), 6-methoxyquercetin (5), 6-methoxykaempferol (6), and 6-methoxykaempferol 7-O-β-d-glucopyranoside (7). Methoxyflavonol glycosides 2–8 also have never been reported from T. tetragonoides in this study. 6-Methoxyflavonols 5 and 6 showed high radical scavenging potential in DPPH and ABTS test. Also, all compounds showed significant anti-inflammatory activities such as reduction of NO and PGE2 formation and suppression of TNF-α, IL-6, IL-1β, iNOS, and COX-2 expression in LPS-stimulated RAW 264.7 macrophages. In general, the aglycones exhibited higher activity than the glycosides. In addition, quantitative analysis of 6-methoxyflavonols in the T. tetragonoides aerial parts extract was conducted through HPLC.

IR spectroscopic measurement of hydrogen production kinetics in methane dry reforming

Dry reforming of methane (DRM) is a reaction that converts two greenhouse gases, CH4 and CO2, to syngas (H2 + CO). Gas chromatography (GC) is almost exclusively used to evaluate catalyst performance. In order to measure the hydrogen production rate with GC, an inert gas with a constant flow rate is usually fed into the system as an internal standard. In this work, an IR spectroscopy-based method is used to achieve the same technical goal with much higher time resolution and much smaller measurement errors. IR measures the molar fractions of CH4, CO2, CO and H2O in the reaction effluent. By applying general mass balance principle and the relevant reaction stoichiometries, H2 production rate is successfully measured without an internal standard. The results are quite close to those obtained by GC with much higher time resolution, making it possible to observe fast reaction kinetics.

Application of the Lagrangian CMC method in elliptic bluff body and swirl flames

The Lagrangian CMC method was implemented in the open source programme OpenFOAM and applied to turbulent nonpremixed bluff body and swirl flames. Lagrangian CMC is more efficient than Eulerian CMC with the number of Lagrangian flame groups much less than the number of computational cells for Eulerian CMC equations in general. It is based on the conditional flame structure depending on the residence time of the fuel of fixed Lagrangian identity from the nozzle. According to sensitivity study the injected fuel was divided into ten flame groups according to the injection sequence with the resulting conditional profiles between those by ISR and Eulerian CMC. Minor deviation from Eulerian CMC was attributed to the flame structure that is difficult to be characterised by the residence time only in elliptic recirculating flows of the bluff body and swirl flames. The Eulerian and Lagrangian CMC showed the same trend of deviation from measurements for conditional temperature, H2O, OH, CO and H2 mass fractions. The significant deviation of H2 was due to uncertainty in the reaction chemistry, as observed in the previous works based on other reaction mechanisms for methane and methanol.

Phase Equilibrium and Critical Phenomena in the n-Pentan–Water and n-Hexane–Water Systems at High Temperatures and Pressures

PVTx-properties of the H2O – n-C5H12 and H2O – n-C6H14 mixtures are measured in the temperature range 303-680 K at pressures up to 60 MPa. The measurements were carried out along 265 liquid and vapor isochors in a density range of 63-713 kg/m3. The measurements were performed for 15 concentrations between 0.110 and 0.987 mole fractions of H2O for the C5H12 mixtures and for 11 concentrations between 0.166 and 0.977 mole fractions of H2O for the C6H14 mixtures. The temperatures and pressures on the three-phase and two-phase boundary curves were obtained for the mixtures from isochors using the kink or inflection method. The data for the critical parameters of the upper and lower branches of the critical curves were obtained from the boundary curves by the method of rectilinear diameter. The measured three-phase data were used to estimate the value of the upper final critical point.

Synthesis of 6,6′‐Bis(O‐4‐arylethynylbenzoyl)‐α,α‐Trehaloses and Their Utilization as Fluorescent Probes for Cellular Imaging

A series of 6,6′‐bis(O‐4‐arylethynylbenzoyl)‐α,α‐trehaloses (aryl groups; 1a: 1‐pyrenyl, 1b: 9‐anthryl, 1c: phenyl) were synthesized and fully characterized. Their photophysical properties were investigated by UV/Vis/fluorescence spectroscopy, and were rationalized by TDDFT calculations. Moreover, the emission maxima of 1a and 1b in THF/H2O considerably shifted to a longer wavelength region with increasing H2O fraction owing to the formation of excimers. The pyrenyl derivative 1a was efficiently taken into HeLa CD4+ human cervical cancer cells and emitted bright green fluorescence.