UV Cut Research Articles

Feasibility study of a photochromic diarylethene film as a clinical dosimeter for kV X-rays

Radiochromic film (RCF) is commonly used as a measurement tool in radiation therapy and diagnostic X-ray imaging. However, the results are not immediately available. This study establishes the workflow of a new diarylethene (DAE) film dosimetry and investigates the film response versus dose against kV X-rays, with the results immediately available for analysis. The DAE film includes a phosphor layer (BaFCl:Eu), a DAE layer, and a UV cut filter. The workflow of the DAE film dosimetry is as follows: (1) irradiation, where the absorbed doses were between 0.1 and 5.0 Gy at 150 kVp X-ray; (2) scanning with blue excitation light (λ = 465 nm) within 1 h of irradiation to obtain a fluorescence intensity map; and (3) analysis of the relationship between the fluorescence intensity and the absorbed dose, and then comparison between such relationship and that between the optical density and absorbed dose of the RCF. Results show that the fluorescence intensity of the DAE film increased with increasing dose. Moreover, the DAE film had a roughly linear response, while the response of RCF was logarithmic (Pearson's correlation coefficients are 0.979 and 0.843, respectively). The DAE film is feasible as a clinical dosimeter of choice.

Visible-Light-Driven Methane Conversion with Oxygen Enabled by Atomically Precise Nickel Catalyst

It remains an extreme challenge to activate thermodynamically unfavorable, chemically inert methane molecules under mild conditions. Herein, we report a molecular-like nickel-thiolate hexameric clu...

5-dimensional Chern-Simons gauge theory on an interval: Massive spin-2 theory from symmetry breaking via boundary conditions

In this note, we revisit the 4-dimensional theory of massive gravity through compactification of an extra dimension and geometric symmetry breaking. We dimensionally reduce the 5-dimensional topological Chern-Simons gauge theory of (anti) de Sitter group on an interval. We apply non-trivial boundary conditions at the endpoints to break all of the gauge symmetries. We identify different components of the gauge connection as invertible vierbein and spin-connection to interpret it as a gravitational theory. The effective field theory in four dimensions includes the dRGT potential terms and has a tower of Kaluza-Klein states without massless graviton in the spectrum. The UV cut of the theory is the Planck scale of the 5-dimensional gravity l−1. If ζ is the scale of symmetry breaking and L is the length of the interval, then the masses of the lightest graviton m and the level n (for n<Ll−1) KK gravitons mKK(n) are determined as m=(ζL−1)12≪mKK(n)=nL−1. The 4-dimensional Planck mass is mPl∼(Ll−3)12 and we find the hierarchy ζ<m<L−1<l−1<mPl.

Phosphomolybdic Acid Prevents Nonspecific Nuclear Staining by Picrosirius Red but Is Converted to Molybdenum Blue by Blue Light.

Picrosirius red (PSR) staining is generally used to evaluate liver fibrosis; however, PSR sometimes causes nonspecific nuclear staining. In this study, we evaluated the ability of phosphomolybdic acid (PMA) pretreatment to prevent nonspecific nuclear staining by PSR. In a manual evaluation of 27 non-tumor samples from patients with hepatocellular carcinoma, nonspecific nuclear staining was observed in 3.7% of PMA-treated specimens, compared with 85.2% of untreated specimens. Conversely, computer-assisted image analysis (CAIA) identified nonspecific nuclear staining in 0% of PMA-treated samples, vs 44.4% of untreated samples. Surprisingly, after mounting, PMA-treated specimens exhibited a blue tinge because of molybdenum blue (MB) production following sunlight exposure or virtual slide scanning. Using UV cut film, MB production induced by sunlight exposure was prevented; however, the film did not prevent MB production during virtual slide scanning. Moreover, only blue light-emitting diode exposure resulted in a blue tinge in PMA solution. Our data indicated that PMA pretreatment is effective for evaluating liver fibrosis using CAIA. Meanwhile, improvements in virtual slide scanning protocols would directly improve the quality of PMA-pretreated specimens subjected to CAIA.

A study on the functional and tensile properties of polyurethane composite film with carbon nanotube fibers

The purpose of this study is to propose a process of fabricating conductive polyurethane (PU)/CNT composite films that possess electrostatic discharge (ESD), UV cut, and warming characteristics. Polyvinylpyrrolidone (PVP), Methyl Ethyl Ketone (MEK), Isopropanol (IPA) were used as the dispersion agent to facilitate the dispersion of CNT fiber before blending with PU in a planetary stirring defoaming machine for thorough uniform mixing. In this study, various amounts of CNT fibers were added into the solvent-based PU solution to improve the electrical conductivity of the conventional PU product. Based on the test results, the PU with CNT fiber shows better performance than that of conventional PU. This paper successfully prepared the PU/CNT composite film which coat on the fabric to prevent static electricity generation, rapid warming, improve home security and the versatility of outdoor and camouflage military products applications.

Stability Improvement of Photovoltaic Performance in Antimony Sulfide-Based Hybrid Solar Cells

Sb2S3-based hybrid solar cells were prepared in the combination with electron transporting layer of TiO2 or ZnO nanoparticles in addition to poly(3-hexylthiophene)-2,5-diyl/(3, 4-ethylenedioxythiophene): poly(styrene sulfonate), zinc phthalocyanine (ZnPc), or MoO3 for hole transporting layer. Photovoltaic performance and durability of the hybrid solar cells were compared each other with or without encapsulation by using glass and UV cutoff film. Among these hybrid solar cells, it was found that a combination of glass-ITO/TiO2/Sb2S3/ZnPC/Au encapsulated with glass and UV cut filter has the highest durability with keeping the relative power conversion efficiency of 90% through the stability test under 1 sun at 63°C at a relative humidity of 50% for 1,500 h.

Construction and Optimization of the Dye Sensitization Solar Cell Using a Au Particle and a Natural Vegetable Pigment

Light of the sun is inexhaustible and clean. The study of the solar cell using light of the sun is currently conducted. Dye sensitization solar cell (DSSC) uses a metal complex having rare and expensive ruthenium (Ru), or organic dye. Therefore, in this study, a pigment from a naturally occurring plant for cost reduction was extracted and was used for sensitizing dye. However, the conversion efficiency of DSSC made using a nature plant pigment is low. Therefore, with reinforced light electric field occurred by the plasmon absorption of metal nanoparticles, the improvement of the conversion efficiency of DSSC using the natural plant pigment was tried. In this session, current density-voltage (i-V) characteristics is reported with construction of DSSC which put Au nanoparticles and the natural plant pigment together.In a 100 mL measuring flask, HAuCl4·4H2O, trisodium citrate dihydrate, and NaBH4 was added to this order to become 0.2 mM, 0.7 mM and 0.3 mM each. Au nanoparticles dispersion liquid was prepared in this way, and was added for triethylene glycol to become 30 vol%. In addition, polyethylene glycol, TiO2, and the sodium dodecyl sulfate aqueous solution were added for this Au nanoparticles dispersion liquid. Resulted mixture was sonicated. The paste, which was prepared by the method mentioned above, was applied on conductive face of an ITO substrate by the squeegee method. Substrate casted was calcined at 500 degrees Celsius for 1 hour. A layer prepared on ITO substrate was assumed as AuTiO2 film. On the other hand, after crushing a grape pericarp or 5 g of Phytolacca americana fruit in the mixer with "an aqueous solution which included 0.993 % by volume TFA in methanol 63.8 % by volume (63.8 vol% acidization methanol)", resulting mixture was filtered, centrifuged, and supernatant solution was provided with pigment solution. TiO2 film on ITO substrate was immersed in the pigment solution which was extracted, and was left at rest in a cool incubator of 5 degrees Celsius for 1 day. After dipping for 1 day, a substrate was washed in ultra-pure water and was dried in air. TiO2 film which was manufactured from the paste which did not include Au nanoparticles dispersion liquid. The AuTiO2 film and the TiO2 film modified with pigment were used as a working electrode. The ITO substrate which sputtered Pt was used as a counter electrode. Using these working and counter electrode, i-V characteristics was measured under the halogen bulb irradiation that transmitted a UV cut filter and a heat-rays absorption filter.By the UV-vis absorption spectrum in the pigment solution which was extracted from Phytolacca americana fruit and Kyoho grape pericarp, the maximum absorption wavelengths was confirmed about two pigment solution in a visible light region of 541 nm and 532 nm, respectively. In addition, in DSSC using the pigment that was extracted from Phytolacca Americana, as a result of i-V characteristics measurement, Light energy conversion efficiency and short circuit photocurrent density of approximately 2.4 times of DSSC using the pigment extracted from Kyoho grape were confirmed. As for this, a hydroxyl group of the TiO2 surface and one of the anthocyanin-based pigment forms hydrogen bonding in DSSC using Kyoho grape pigment, but it is thought that this is because electron transfer from the pigment to TiO2 was performed more effectively than a case of Kyoho grape because the carboxy group of the Betalain series dye and the hydroxyl group of the TiO2surface form ester bond in DSSC using the Phytolacca americana pigment. At present, to identify a nature pigment, structure analysis are being examined.Au nanoparticles dispersion liquid and the Phytolacca Americana pigment solution respectively showed the maximum absorption wavelength of 526 nm and 549 nm by UV-vis absorption spectrum. The conversion efficiency of DSSC which was assembled with AuTiO2 film and TiO2 film was respectively 0.05287 % and 0.01669 %. The difference in this conversion efficiency depends on magnitude relation of the short circuit photocurrent density. Charge transfer resistance decreases by adding the Au nanoparticles which are a metal to TiO2 which is a semiconductor, and it is thought that short circuit photocurrent density increased. In addition, it is thought that this is because the excitation of the pigment became easy to happen by reinforced light electric field occurred by the plasmon absorption of metal nanoparticles. The improvement of the conversion efficiency was confirmed, but performance is largely low in comparison with general DSSC. Therefore, by ac impedance measurement, the resistance ingredient in the cell is identified and the construction condition of the cell is being examined.

Highly Efficient Visible-Light Driven Carbon Particles/g-C3N4 Photocatalysts with Enhanced Photocatalytic H2 Production

As a typical metal free inorganic semiconductor, graphitic C3N4 (g-C3N4) has attracted intensive attention for H2 generation, pollutant degradation and CO2 reduction. It is well-known that the band gap of g-C3N4 is about 2.7 eV, which can absorb visible light up to 460 nm. Furthermore, the conduction band minimum of g-C3N4 is extremely negative, so photogenerated electrons should have high reduction ability. However, the photocatalytic efficiency of the pure g-C3N4 is limited by the high recombination rate of its photo-generated electron–hole pairs. One of the techniques for increasing the separation efficiency of photo-generated electron–hole pairs is to load a nonmetal element into a photocatalyst. For the increase of the photocatalytic activity, an extensively studied carbonaceous candidate is carbon particles with tunable size and band gap, abundant hydrophilic surface groups, and long term stability. Particularly, carbon particles can act as spectral converters to overcome the contradiction between optical absorption and chemical reaction dynamics of various semiconductors with UV and visible light activity because of its large cross-section of upconversion absorption and a wide range of emission spectra that boost the energy band-gap matching. In this study, novel carbon particles and g-C3N4 composite photocatalysts were prepared through a facile two-step calcination using carbon particles and melamine as a starting material. The synthesized samples were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), nitrogen-sorption, UV-Vis diffuse reflectance spectra (DRS), photoluminescence spectra (PL), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Photocatalytic activity of carbon particles modified g-C3N4 (C/g-CN) was evaluated by photocatalytic hydrogen production under visible irradiation (λ ≧ 420 nm). Firstly, 3.6 g of glucose was dissolved in distilled water (40 mL) to form a clear solution, then 40 mL of concentrated HCl solution was dropped into the solution of glucose. Afterward, the mixture solution was transferred into a 100 mL Teflon liner followed by hydrothermal treatment at 180 ℃ for 6 h. After hydrothermal reaction, the black precipitates were centrifuged and get brown carbon particles solution. Carbon particles and g-CN composite photocatalysts were prepared by two step calcination of the mixture of carbon particles and melamine. Before calcination, 5 mL of carbon particles suspension in ethanol was added into 3g of melamine, then ethanol was evaporated. This obtained ingredient was applied two times calcination, first heating at 550 ℃ for 3h, second heating at 500 ℃ for 10h. Physicochemical measurement of the samples were characterized by XRD, FT-IR, XPS, nitrogen-sorption, DRS, PL, SEM, and TEM. The pyrex column vessel reactor (inner volume: 123 mL) was used for the photocatalytic H2 production from aqueous solution (40 mL) containing 10 vol% triethanolamine (TEA) as a sacrificial donor. 2 wt% Pt loaded on the surface of the photocatalyst by the in situ photodeposition method using H2PtCl6. Before irradiation, N2 gas was bubbled into the reaction solution for 30 min to remove a dissolved O2. Typically, 40 mg of the photocatalyst were added into the reaction solution. A 300 W Xe lamp with a UV cut filter (λ<420 nm) was applied as a light source. The concentration of H2 production from the aqueous TEA solution was analyzed by GC with TCD. The rate of hydrogen production for pure g-CN was approximately 7.9 μmol/g・h. After modified carbon particles, photocatalytic performance was higher. The highest photocatalytic hydrogen evolution rate for 0.5 wt% C/g-CN was approximately 340 μmol/g・h, which was about 43 times faster than that of pure g-CN. DRS spectra showed that the absorbing wavelength region expanded after loading carbon particles. Especially, 5.0 wt% C/g-CN could be absorbed over NIR. However, the photocatalysts which is the highest photocatalytic performance is 0.5 wt% C/g-CN. This result was attributed to the light shading effect. PL spectra represented the peak intensity of C/g-CN were weaker than that of pure g-CN. In this case, this result was implied to preventing recombination of electron-hole pairs which derived from carbon particles loaded. In conclusion, the highest photocatalytic hydrogen evolution rate for 0.5 wt% C/g-CN was approximately 340 μmol /g・h, which was about 43 times higher than that of pure g-CN. The improved photocatalytic activity was attributed to the fact that carbon particles acted electron reservoirs to trap the electrons for promoting charge separation and light harvesters to enhance the visible light absorption.

(Invited) Long Term Stability of Antimony Sulfide-Based Hybrid Solar Cells

Sb2S3-based hybrid solar cells with electron transporting layer of TiO2 or ZnO nanoparticles in addition to poly(3-hexylthiophene)-2,5-diyl / (3, 4-ethylenedioxythiophene) : poly(styrene sulfonate), zinc phthalocyanine (ZnPc), or MoO3 for hole transporting layer were prepared and compared their photovoltaic properties with or without encapsulation by using glass and UV cut-off film. Among these hybrid solar cells, it was found that a combination of glass-ITO/TiO2/Sb2S3/ZnPC/Au encapsulated with glass and UV cut filter has the highest durability with keeping the relative power conversion efficiency of 90% through the stability test under 1 sun at 63 °C at a relative humidity of 50% for 1,500 h.

(Invited) Long Term Stability of Antimony Sulfide-Based Hybrid Solar Cells

Recently various materials such as antimony sulfide (Sb2S3),1,2) antimony selenide,3) lead sulfide,4) cadmium selenide,5) lead-halogen perovskite6-8) have been applied for organic-inorganic hybrid solar cells. Among these materials, Sb2S3 has much attraction for photovoltaics in terms of appropriate bandgap, high absorption coefficient, low toxicity, and abundance. Sb2S3 has been prepared by chemical bath deposition, atomic layer deposition, complex-decomposition method, and so on and applied as the thin film for solar cell, which has been attained the power conversion efficiency (PCE) of 7.5%.1) Although Sb2S3-based solar cell seems to be stable in air,2) stability test under the accelerated conditions has not yet been reported. In addition, various materials such as SnO2, TiO2, or ZnO have been utilized as an electron transporting layer (ETL) and polythiophenes, 2,2’,7,7’-tetrakis(N,N-di-p-methoxyphenylamine)-9,9’-spirobifluorene, ZnPc, CuSCN, MoO3, or NiO have been used as a hole transporting layer (HTL) of the Sb2S3 based solar cells, however, optimization of the combinations of ETL and HTL in terms of the durability has also not yet been explored. In this context, we prepared Sb2S3-based solar cells with TiO2 or ZnO nanoparticles for ETL in addition to poly(3-hexylthiophene)-2,5-diyl (P3HT)/ (3, 4-ethylenedioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS), ZnPc, or MoO3 for HTL and compared their photovoltaic properties with encapsulation by using glass and UV cut-off films under JIS C8938 conditions of 1 sun at 63 °C at a relative humidity (RH) of 50%. Among these hybrid solar cells, combination with ZnPc and TiO2 has the highest durability with keeping the relative power conversion efficiency of 90% after the stability test under 1 sun at 63 °C at a RH of 50% for 500 h. In order to investigate the effect of UV light irradiation, another durability test of glass-ITO/TiO2/Sb2S3/ZnPC/Au without UV cut filter was performed The photovoltaic performance was completely maintained for 3 d with UV cut filter, however it has almost been lost without the cut filter after 3 d. Decolorization was observed after the irradiation without the UV cut filter though the decolorization did not occur with the filter. Once the TiO2 layer was removed from the cell, described as glass-ITO/ Sb2S3/ZnPC/Au, there was no decolorization even when without using the UV cut filter. In this context, anatase TiO2 nanoparticles in this case act as the photocatalyst during the UV light irradiation to oxidize and decompose Sb2S3, which resulted in the above decolorization of the cells. Therefore, effective suppression of the photoactivation of TiO2 through UV light irradiation by using cut filter is essential to realize the long term stability and promising further extension for optimization of the photovoltaic performance. J. A. Chang, J. H. Rhee, S. H. Im, Y. H. Lee, H. J. Kim, S. I. Seok, M. K. Nazeeruddin, and M. Graetzel, Nano Lett., 2010, 10, 2609–2612.Y. C. Choi, D. U. Lee, J. H. Noh, E. K. Kim, and S. I. Seok, Adv. Funct. Mater. 2014, 24, 3587-3592.N. Guijarro, T.Lutz, T.Lana-Villarreal, F. O’Mahony, R. Gomez, and S. A. Haque, J. Phys. Chem.Lett., 2012, 3, 1351-1356.H. Wang, T. Kubo, J. Nakazaki, T. Kinoshita, and H. Segawa, J. Phys. Chem. Lett. 2013, 4, 2455-2460.P. K. Santra and P. V. Kamat, J. Am. Chem. Soc., 2012, 134, 2508-2511.A. Kojima, K. Teshima, Y. Shirai, T. Miyasaka, J. Am. Chem. Soc., 2009, 131, 6050-6051.M. M. Lee, J. Teuscher, T. Miyasaka, T. N. Murakami, H. J. Snaith, Science, 2012, 338, 643-647.W. S. Yang, J. H. Noh, N. J. Jeon, Y. C. Kim, S. Ryu, J. Seo, S. I. Seok, Science, 2015, 348, 1234-1237.

Risk Points of Flame Retardant Textiles by Halogen and Halogen-Free Laminating Film

This study was to develop the flame retardant (FR) protective clothing which had multifunction such anti-bacterial, UV cut, FR function with water repellent and water vapor permeable laminating textiles for industrial workers. First of all, the FR yarn and FR textiles were developed for this purpose. Second, the comparison analysis between the halogen laminating textiles and halogen-free laminating textiles were tested to figure out the eco-friendly laminating method. Third, the flame retardant ability was compared the halogen laminated textiles to halogen-free laminated textiles. LOI, UV protection ratio, antibiosis after 50 laundry test, water proof pressure, and moisture permeability of developed textiles were tested. GC-HR-TOF-MS was used for analysis of laminating film (halogen and halogen-free). 4.1 wt% TiO2 yarn showed antibacterial function (Pneumococcus & Staphylococcus aureus: 99.9%), UV Protection (UVA: 90.8, UVB: 92.1), and LOI (33.6). The chosen optimal compounding ratio for PU compound of HRF and HFFR were as followed: PU resin 58.3%, DMF (Dimethyl formamide, δ = 12.2) 8.3%, MEK (Methylethylketone) 8.3% and FR (flame retardants) 25.0%. Binder for laminating should not be included over 10% of FRs because of adhesion between textiles and FR laminating film. There were detected phosphorus compounds in the textiles treated by halogenated type flame retardants and halogenated-free type flame retardants. There were not any detected harmful compounds from all textile samples.

Effect of Co2+ on the growth and physical properties of potential nonlinear optical l-Asparaginium picrate crystal

l-Asparaginium picrate (LASP) is a good nonlinear optical material having large second harmonic generation (SHG) efficiency. In the present study LASP crystal is grown with metallic dopant cobalt (Co2+) for different molar concentrations by a low temperature solution growth using slow evaporation technique. The grown crystals are subjected to single crystal and powder X-ray diffraction studies to identify the morphology and structure. The addition of Co2+ at different molar concentration improves the morphology of LASP crystal considerably. The dopant concentration in the doped crystal is estimated by inductively coupled plasma emission analysis (ICP-OES). The UV cut of range is determined by optical absorption study. The NLO behavior of Co2+ doped LASP crystals is tested by Kurtz–Perry technique. The TG-DTA studies showed that the doped crystal exhibit better thermal stability than pure LASP.

Titanium–oxo–Clusters with Dicarboxylates: Single-Crystal Structure and Photochromic Effect

Two titanium-oxo-clusters Ti(6)O(4)(o-BDC)(2)(o-BDC(i)Pr)(2)(O(i)Pr)(10) (1) and Ti(6)O(3)(o-BDC)(2)(O(i)Pr)(14) (2) (BDC = benzene dicarboxylate) were prepared by one-step in situ solvothermal synthesis. The compounds are the rare examples of the dicarboxylate-substituted titanium-oxo-clusters. Their crystal structures are successfully measured by single-crystal X-ray analysis. The Ti(6) oxo-clusters of 1 and 2 are constructed by two dual corner-missing cube subunit, Ti(3)O(3). The two subunits are linked by double μ(3)-O bridges for 1 and single μ(2)-O bridge for 2, respectively, and the latter is a new type of carboxylate substituted titanium-oxo-cluster. A photochromic effect was observed upon irradiation of the crystals in the presence of alcohol. The light irradiation changed the color of the crystals from transparent to purple-gray. The Ti(III) signal was detected after the irradiation, and when the sample was exposured in air, superoxide diatomic O(2)(•-) radical was found. Photodegradation of the methyl orange in aqueous dispersions of microcrystals of the cluster 2 was carried out under UV cut white light with the assistance of H(2)O(2).

Synthesis, growth and characterization of nonlinear optical urea–ammonium chloride crystals

Semi-organic nonlinear optical urea–ammonium chloride (UAC) crystals have been grown from aqueous solution by slow evaporation technique. The lattice parameters of the grown crystals were determined by X-ray diffraction studies. The presence of functional groups was determined using Fourier transform infrared (FTIR) analysis. The thermal analysis studies indicate that the material possess optimum thermal stability. Optical absorption studies show low absorption in the entire visible region and UV cut – off is found to be at 240 nm. The presence of second harmonic generation (SHG) for the grown crystal was confirmed by Kurtz powder technique.

A photochemical cell with nano-porous TiO 2 electrode sensitized by lignophenol under visible light irradiation

A photochemical solar cell sensitized with a lignophenol, which has been directly synthesized from lignocellulosics through the phase-separation system, on a nano-porous TiO 2 film electrode was developed and improved by stirring, reflux and saturation in an acetone solution. Hinoki ( Chamaecyparis obtusa)-lignophenol ( p-cresol type, HKLC), Beech ( Fagus crenata)-lignophenol ( p-cresol type, BCLC), second derivatives-I of HKLC and BCLC (HKLC413, BCLC413) and second derivatives-II of HKLC and BCLC (HKLC443, BCLC443) were used as photo-sensitizers. The conversion of visible light from 150-W Xe lamp through a L41 UV cut filter into electricity was achieved with a sandwich-type cell consisted of FTO-glass-TiO 2 film-lignophenol-electrolytes-Pt coated FTO. The open circuit photovoltage ( V oc), the short-circuit photocurrent density ( I sc), the fill factor (FF) and the photo-electricity conversion efficiency ( η) for the cell with HKLC413 saturated on TiO 2 electrode were estimated under 85.0 mW cm −2 visible light irradiation for 0.51 V, 10.23 mA cm −2, 0.59 and 3.61% respectively. On the other hand, the cell with HKLC saturated only on the surface of TiO 2 electrode was estimated for η = 0.81%. Moreover, the amounts of HKLC413 and HKLC443 on the electrodes extracted by 1.0 M NaOH were larger than the amount of HKLC evaluated by UV–vis spectroscopy. After the extractions were carried out in NaOH, only both HKLC413 and HKLC443 were remained in electrodes with slight yellow appearances. These results indicated that lignophenols were adsorbed on the inner part of porous TiO 2 electrodes. Consequently, the performances of these cells were strongly influenced by the molecular sizes and the structures of lignophenols.

Nd 3+:Y 3Al 5O 12 laser ceramics: Flashlamp pumped laser operation with a UV cut filter

A Nd 3+:Y 3Al 5O 12 ceramic laser under the hard-UV cutting condition of Xe flashlamp pumping was demonstrated for the first time. By using a 16.4 kW Xe flashlamp and a samarium-doped flow tube, an average laser output power of 386 W was obtained at 1064 nm with a 1.1 at.% Nd 3+:Y 3Al 5O 12 ceramic rod of Ø10 mm × 152 mm. The slope efficiency was measured to be 2.3%, which was the same as for a Nd 3+:Y 3Al 5O 12 single crystal rod of similar size. The degradation of output power by the solarization effect was found to be negligible when the UV radiation below 350 nm wavelength was cut by a Sm:glass flow tube.

Photoelectrochemical Properties of J Aggregates of Benzothiazole Merocyanine Dyes on a Nanostructured TiO2Film

We studied the photoelectrochemical properties of nanoporous TiO2 electrodes sensitized by a series of benzothiazole merocyanine dyes, 3-carboxyalkyl-5-[2-(3-alkyl-2-benzothiazolinyldene) ethylidene]-2-thioxo-4-thiazolidinone, having a different alkyl chain length. Broadening of absorption spectra and a large red shift of the absorption threshold up to 680 nm were observed by adsorbing dyes on a porous TiO2 electrode, suggesting the formation of various kinds of J aggregates of the dye on the TiO2 surface. The dye was fixed by a chelate-like linkage of the carboxylate anchoring group on the TiO2 surface, rather than by an ester linkage. The solar light-to-power conversion efficiency (ηsun) and the incident photon-to-current conversion efficiency (IPCE) increased with increasing the length of alkyl chain attached to the benzothiazole ring. The maximum ηsun value was 4.5%, which is the second highest value among organic dye systems reported so far (AM-1.5, 100 mW/cm2). The J aggregates of the dyes having long alkyl chains showed an excellent ability for sensitization on the TiO2 electrode, whereas those having short alkyl chains hardly showed the sensitization especially at a light wavelength (λ) of >600 nm. The IPCE decreased significantly with increasing methylene length between the carboxyl anchoring group and the dye chromophore, that is, the conjugated skeleton, suggesting that the distance between the chromophore and the TiO2 surface affected the IPCE. Moreover, a formation of fine packing of the dye chromophores in the J aggregate has proved to be important to obtain a high IPCE. We tested also the stability of the dye in a sealed solar cell under simulated solar light with an UV cut filter. The ηsun and the color of the dye remained unchanged for more than 750 h, and the total turnover number of the dye for the photon-to-electron conversion exceeded 1.6 × 106 cycles, suggesting that the merocyanine dye itself is fundamentally stable during the photoreaction in this system without UV irradiation.

Chlorine Source and Wavelength Range in the Chlorination of Pyrene in Soil with Sunlight Irradiation.

In this study, the source of chlorine and the range of wavelength on the chlorination of pyrene in soil after the sunlight irradiation in ordinary atmospheric air were investigated. Chloride ions and pyrene were added to soil, and sunlight was irradiated. The reaction products including the original pyrene and chlorinated pyrenes in soil after the irradiation were extracted with a mixture of benzene and ethanol (4 : 1, v/v) using the sonication technique. The extracts were then cleaned up using florigil column chromatography before GC-MS (SIM) determination. The formation of chlorinated pyrenes in soil washed with distilled water was found to be strongly dependent on the concentration of chloride ions spiked in soil. It was found that the chlorinated pyrenes produced in air-dried soil after the sunlight irradiation were less than those in air dried soil spiked with chlorine ions and that the formation of chlorinated pyrenes in soil was extremely depressed by the wrapping with UV cut films. Consequently, it was also found that the chlorine source to produce chlorinated pyrenes in soil after the sunlight was mainly water soluble chloride ions and that the ultraviolet light of less than 380 nm mainly affected the formation of chlorinated pyrenes.

Whole-body fluorography using black light fluorescent tubes.

A simple and inexpensive apparatus and techniques are described for recording fluorographs of whole-body cryosections of mice injected with a fluorescent compound. The apparatus was constructed with commercial fluorescent tubes which emit UV light of 300-400nm and a single-lens reflex camera equipped with UV cut and Kodak Wratten filters.Autofluorescence of the whole-body section observed by using this technique was discussed and the effects of lapse of time after cryosectioning, fixation, and pH on the autofluorescence were also investigated. Autofluorescence of the skeletal muscle, myocardium, smooth muscle, brain, kidney cortex and pancreas was intensified with time after cryosectioning, but that of the Harderian gland was gradually faded. In other tissues, autofluorescence remained unchanged up to 2 weeks after cryosectioning. All fixatives used in this experiment reduced the autofluorescence of tissues and organs. Among the fixatives, 100% acetone had the least effect on autofluorescence. At pH4, autofluorescence of all tissues was considerably increased in comparison with pH7. With increasing pH, autofluorescence of most tissues was gradually reduced except for the bones and the Harderian gland.

Photocross-linking from DNPated SH1 in myosin head. I. Cross-linking to the 50-kDa fragment.

When DNP-SH1-myosin, selectively dinitrophenylated at SH1 by 1,2,4-trinitrobenzene, was irradiated with a high-pressure mercury lamp equipped with a UV cut filter, a new 220-kDa band called the X-band appeared right above the heavy chain band (200 kDa) on SDS-PAGE (Laemmli). The time course of the X-band formation was composed of two phases, the initial one being rapid, and the second slow. Immune reaction experiments using antibodies specific for heavy or light chains indicated that the X-band in the initial phase contained heavy chain alone, but no light chains. Such an extra band (106 kDa) was also observed in the initial phase of photolysis of DNP-SH1-Subfragment-1 (heavy chain: 96 kDa) obtained from DNP-SH1-myosin. Trypsinolysis of the 106-kDa product generated a 83-kDa band. N-Terminal sequence analysis and the amino acid composition of the band revealed that the X-band is an intraheavy chain cross-linking product between the 20- and the 50-kDa fragments. This presents a striking contrast to the other cross-linking from SH1 using benzophenone-4-iodoacetamide which reacted with the 25-kDa fragment alone (Lu, R.C. et al. (1986) Proc. Natl. Acad. Sci. U.S. 83, 6392-6396). Based upon the result obtained, the spatial arrangement of the three tryptic domains around SH1 is discussed.