Antarctic red algae in dye-sensitized photoelectrochemical cells for water splitting

Phycoerythrin extracted from Antarctic red seaweeds shows promising characteristics to be applied as an anode sensitizer in water-splitting photoelectrochemical cells.Under light irradiation and using an LED lamp,the red-colored protein shows an interesting ability to profit the incident light,as confirmed by the presence of oxygen bubbles next to the electrode surface without applying any external potential.Our results showed that the addition of iodide is helpful to allow the regeneration of the dye;nevertheless,oxygen evolution is not favored.Thermodynamics analysis of the involved semi-reactions is also helpful to understand the observed results.The exploration of Antarctic resources offers then an alternative for the development of green energies,with a particular focus on their use as sensitizers to profit from the sunlight in water-splitting as well as in photovoltaic devices.

Comparison of immune responses and intestinal flora in epicutaneously sensitized BALB/c or C57BL/6 mouse models of food allergy

Cutaneous exposure to food allergens through a disrupted skin barrier is recognized as an important cause of food allergy,and the cutaneous sensitized mouse model has been established to investigate relevant allergic disorders.However,the role of different genetic backgrounds of mice on immune responses to food allergens upon epicutaneous sensitization is largely unknown.In this study,two strains of mice,i.e.,the BALB/c and C57BL/6 mice,were epicutaneously sensitized with ovalbumin on atopic dermatitis(AD)-like skin lesions,followed by intragastric challenge to induce IgE-mediated food allergy.Allergic outcomes were measured as clinical signs,specific antibodies and cytokines,and immune cell subpopulations,as well as changes in intestinal barrier function and gut microbiota.Results showed that both strains of mice exhibited typical food-allergic symptoms with a Th2-skewed response.The C57BL/6 mice,rather than the BALB/c mice,were fitter for establishing an epicutaneously sensitized model of food allergy since a stronger Th2-biased response and severer disruptions in the intestinal barrier and gut homeostasis were observed.This study provides knowledge for selecting an appropriate mouse model to study food-allergic responses associated with AD-like skin lesions and highlights the role of genetic variations in the immune mechanism underlying pathogenesis of food allergy.

Efficient quantum dot sensitized solar cells via improved loading amount management

High light-harvesting efficiency and low interfacial charge transfer loss are essential for the fabrication of high-efficiency quantum dot-based solar cells(QDSCs). Increasing the thickness of mesoporous TiO2films can improve the loading of pre-synthesized QDs on the film and enhance the absorbance of photoanode, but commonly accompanied by the increase in the unfavorable charge recombination due to prolonged electron transmission paths. Herein, we systematically studied the influence of the balance between QD loading and TiO2film thickness on the performance of QDSCs. It is found that the relative thin photoanode prepared by the cationic surfactant-assisted multiple deposition procedure has achieved a high QD loading which is comparable to that of the thick photoanode commonly used. Under AM 1.5G illumination, Zn–Cu–In–Se and Zn–Cu–In–S based QDSCs with optimized 11.8 μm photoanodes show the PCE of 10.03% and 8.53%, respectively, which are comparable to the corresponding highest PCE of Zn–Cu–In–Se and Zn–Cu–In–S QDSCs(9.74% and 8.75%) with over 25.0 μm photoanodes. Similarly, an impressive PCE of 6.14% was obtained for the CdSe based QDSCs with a 4.1 μm photoanode, which is slightly lower than the best PCE(7.05%)of reference CdSe QDSCs with 18.1 μm photoanode.

Assembly of Covalently Inorganic-Organic Hybrid Molecular Framework Based on Porphyrin and Phthalocyanine Derivatives—Sensitizer for Dye Sensitized Solar Cells

The research on sensitizer for dye sensitized solar cells based on (metallo)porphyrin/phthalocyanine materials were reviewed, and experimental design and assembly method were advised. Latest progress and research status of sensitizer dyes based on metalloporphyrins applied in dye sensitized solar cells was summarized. The preparation and construction of sensitizer electrodes and dye sensitized solar cells based on metal organic frameworks (MOFs) of (metallo)porphyrin/phthalocyanine were projected.

Characterization of Dye Sensitized Cells Using Natural Dye from Oil Bean Leaf (<i>Pentaclethra macrophylla</i>): The Effect of Dye pH on the Photoelectric Parameters

Fresh leaves of oil bean (P. macrophylla) were used as sensitizers for fabrication of dye sensitized solar cells (DSSCs) at four dye pH values of 2.58°C at 23.7°C, 2.62°C at 22.2°C, 2.65°C at 22.3°C and 3.61°C at 22.1 °C. The methanol extracts of P. macrophylla were extracted and used as sensitizers for the development of dye sensitized solar cells. The solar cells sensitized by P. macrophylla leaf extracts realised up to short circuit current (Jsc) 0.16 mA/cm2, open circuit voltage (Voc) 0.045 V, Pmax 0.031 mW/ cm2 and fill factor (FF) 0.50. The energy conversion efficiency (η) of the DSSCs is 0.43%. Phytochemical screening of P. macrophylla leaf extract shows the presence of flavonoids and anthraquinones. The nanostructured dye shows conversion of solar energy into electricity using low cost natural dyes as wide band-gap semiconductor sensitizers in DSSCs. This will provide economically viable substitute to silicon p-n junction photovoltaic (PV).

The Effect of Electrolyte on Dye Sensitized Solar Cells Using Natural Dye from Mango (<i>M. indica</i>L.) Leaf as Sensitizer

Dye-sensitized solar cells (DSSC) were fabricated with mango leaf dye extracts as natural dye sensitizers at pH value of 5.20 and temperature of 18.1°C. Methanol was used as dye-extracting solvent. DSSCs from dye extract of M. indica L. with KMnO4 electrolyte had the highest photocurrent density of 1.3 mA/cm2 and fill factor FF of 0.46 for the sun at its peak. Potassium permanganate (KMnO4) had a photocurrent density of 1.3 mA/cm2 and FF of 0.8 at sundown. Potassium Iodide (KI), Potassium Bromide (KBr) and Mercury Chloride (HgCl2) electrolytes had 0.2 mA/cm2, 0.08 mA/cm2 and 0.02 mA/cm2 photocurrent densities respectively. The fill factors of 0.09, 0.03 and 0.003 respectively for sun overhead while 0.08 mA/cm2, 0.01 mA/cm2 and 0.01 mA/cm2 were the values of photocurrent densities respectively at sundown. The fill factors were 0.02, 0.0006 and 0.003 respectively at sundown. The maximum power Pmax of the DSSCs were 0.5 mW/cm2, 0.10 mW/cm2, 0.01 mW/cm2 and 0.012 mW/cm2 respectively at 1300 h at 1630 h 0.9 mW/cm2, 0.14 mW/cm2, 0.005 mW/cm2 and 0.0015 mW/cm2 respectively.

Insulin sensitizers for the treatment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease(NAFLD) is the leading cause of liver disease in the Western world and is closely associated with metabolic syndrome,which includes hypertension,central obesity,dyslipidemia and insulin resistance.NAFLD includes a wide spectrum of liver alterations,ranging from simple hepatic steatosis to variable degrees of fibrosis,cirrhosis and even hepatocellular carcinoma.Although the etiology and progression of the disorder remain poorly understood,insulin resistance is considered to play a pivotal role in the pathogenesis.Insulin sensitizers such as biguanides,thiazolidinediones(TZDs),glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase 4 inhibitors have been studied as therapeutic approaches for NAFLD in recent years.Metformin improves insulin sensitivity and serum alanine transaminase and aspartate transaminase(ALT/AST) levels in the majority of subjects; however,it has no significant effect on liver histology.TZDs improve insulin sensitivity,serum ALT/ AST levels and histology in some cases,but there are some concerns about the safety of long-term therapy.Selection of appropriate patients for avoiding side effects and the treatment of underlying disease are themain points.These drugs are the best choice for the treatment of NAFLD in patients with type 2 DM who are also candidates for treatment with an insulin sensitizer.The present review provides an overview of insulin sensitizers in the treatment of NAFLD.

Photodegradation of methyl orange by BiOI-sensitized TiO_2

BiOI-sensitized titanium dioxide (TiO2) photocatalysts were prepared by a deposition method at room temperature and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller surface area measurements. The photocatalytic activities of the catalysts were evaluated for the degradation of methyl orange (MO) solution under UV and visible light irradiation. The effects of catalyst amount, initial pH value, initial concentration of MO, as well as KI amount were investigated. The repeatability of photocatalytic activity of the 1.7% BiOI/TiO2 catalyst was also tested. It is shown that BiOI sensitization enhances the photocatalytic activities of TiO2. With BiOI content increasing, the photocatalytic activities of BiOI/TiO2 under UV and visible light irradiation first increase, reaching a maximum around BiOI content of 1.7%, and then decrease with further increasing BiOI content. The 1.7% BiOI/TiO2 catalyst obviously exhibits much higher visible light photocatalytic activity than P25, and its UV light photocatalytic activity is slightly higher than that of P25. Under the conditions of a catalytic dose of 1.5 g.L-1, initial pH of 3.0, initial MO concentration of 20 mg.L-1, UV power of 300 W, and air flow rate of 0.8 L.min-1, complete degradatio is achieved within 60 min. The repeatability of photocatalytic activity of the 1.7% BiOI/TiO2 catalyst is highly reliable.

Titania Nanostructures for Dye-sensitized Solar Cells

Titania is one kind of important materials, which has been extensively investigated because of its unique electronic and optical properties. Research efforts have largely focused on the optimization of the dye,but recently the titania nanostructures electrode itself has attracted more attention. It has been shown that particle size, shape, crystallinity, surface morphology, and chemistry of the TiO_2 material are key parameters which should be controlled for optimized performance of the solar cell. Titania can be found in different shape of nanostructures including mesoporous, nanotube, nanowire, and nanorod structures. The present article reviews the structural, synthesis, electronic, and optical properties of TiO_2 nanostructures for dye sensitized solar cells.

Colchicine sensitizes human hepatocellular carcinoma cells to damages caused by radiation

AIM： We studied the effect of colchicine combined with radiation on the survival of human hepatocellular carcinoma （HCC） HA22T/VGH cells.METHODS： Twenty-four hours after treatment with 0-8 ng/mL colchicine, HA22T/VGH cells were irradiated at various doses （0, 1, 2, 4, and 8 Gy）. Colony assay was performed to assess the surviving cell fraction. Survival curves were fitted by using a linear-quadratic model to estimate the sensitizer enhancement ratio （SER）. Flow cytometry was used for cell cycle analysis.RESULTS： Colchicine at lower concentrations （1 and 2 ng/mL） had obvious synergy with radiation to inhibit HCC cell growth, whereas higher concentrations （4 and 8 ng/mL） had only additive effect to radiation. Pretreatment with 1 and 2 ng/mL colchicine for 24-h enhanced cell killing by radiation with SERs of 1.21 and 1.53, respectively.G2/N arrest was only observed with higher colchicine doses （8 and 16 ng/mL） after 24-h treatment, this effect was neither seen with lower doses （1, 2, and 4 ng/mL）nor with any dose after only 1 h of treatment.CONCLUSION： Our results suggest that colchicine has potential as an adjunct to radiotherapy for HCC treatment.Lower doses of colchicine possess radiosensitizing effects via some mechanism other than G2/M arrest. Further study is necessary to elucidate the mechanism.

Formation of active radicals and mechanism of photocatalytic degradation of phenol process using eosin sensitized TiO_2 under visible light irradiation

The role of oxygen and the generation of active radicals in the photocatalitic degradation of phenol were investigated using the eosin sensitized TiO2 as photocatalyst under visible light irradiation. Diffuse reflectance spectra show that the absorbancy range of eosin/TiO2 is expanded from 378 nm (TiO2 ) to about 600 nm. The photocatalitic degradation of phenol is almost stopped when the eosin/TiO2 system is saturated with N2 , which indicates the significance of O2 . The addition of NaN 3 (a quencher of single oxygen) causes about a 62% decrease in the phenol degradation. The phenol degradation ratio is dropped from 92% to 75% when the isopropanol (a quencher of hydroxyl radical) is present in the system. The experimental results show that there are singlet oxygen and hydroxyl radical generated in the eosin/TiO2 system under visible light irradiation. The changes of absorbancy indicate that the hydrogen peroxide might be produced. Through the analysis and comparison, it is found that the singlet oxygen is the predominant active radical for the degradation of phenol.

Synthesis of a Polymer-bound Sensitizer and its Application in the Photoisomerization of trans-Vitamin D_3 to cis-Vitamin D_3

A polymer-bound photosensitizer was synthesized by the reaction of Merrifield resin with 9-anthracenemethanol in the presence of potassium hydride. The photoisomerization of trans-vitamin D3 to cis-vitamin D3 was carried out with this polymer-bound photosensitizer in ethanol and toluene solutions. The experiment results demonstrate that this solid photosensitizer is efficient for the photoismerization and easy for separation from the reaction mixtures.

200-nm long TiO_2 nanorod arrays for efficient solid-state Pb S quantum dot-sensitized solar cellsR

To ensure the infiltration of spiro-OMeTAD into the quantum dot-sensitized photoanode and to consider the limit of the hole diffusion length in the spiro-OMeTAD layer, a rutile TiO2 nanorod array with a length of 200 nm, a diameter of 20 nm and an areal density of 720 ram 2 was successfully prepared using a hydrothermal method with an aqueous-grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 ℃ for 75 min. PbS quantum dots were deposited by a spin coating-assisted successive ionic layer adsorption and reaction （spin-SILAR）, and all solid-state PbS quantum dot-sensitized TiO2 nanorod array solar cells were fabricated using spiro-OMeTAD as electrolytes. The results revealed that the average crystal size of PbS quantum dots was -78 nm using Pb（NO3）2 as the lead source and remain unchanged with the increase of the number of spin-SILAR cycles. The all solid-state PbS quantum dot-sensitized TiO2 nanorod array solar cells with spin-SILAR cycle numbers of 20, 30 and 40 achieved the photoelectric conversion efficiencies of 3.74%, 4.12% and 3.11%, respectively, under AM 1.5 G illumination （100 mW/cm2）.

Determination of Residual Enrofloxacin in Fish Tissues by Terbium Ion-sensitized Fluorophotometry

In order to establish a new method for the determination of enrofloxacin, on the basis of the fluorescence characteristic of terbium-enrofloxacin complex, it was found that in a HAc-NaAc buffer solution with a pH value at 6.0, the terbiumenrofloxacin complex had a characteristic fluorescence peak of Tb3＋ at 545 nm （λex= 328 nm）, which could be used for the determination of enrofloxacin. A simple, rapid and sensitive fluorescence method for the determination of enrofloxacin was thus established, and an optimal reaction condition was selected. Under the optimal reaction condition, there was a good linear relation （r2=0.992 3） between concentration of enrofloxacin in the range of 1.0×10^-1.0×10^-6 g/ml and its fluorescence intensity at 545 nm, with a detection limit of 1.3×10^-9 g/ml; the recovery for enrofloxacin in tablets was 97.7% with a variation coefficient of 1.4%; and for enrofloxacin in fish tissues, the recovery was 79.0%-94.5% with a variation coefficient of 2.0%-7.8%.

CdS Quantum Dots-sensitized TiO_2 Nanotube Arrays for Solar Cells

CdS quantum dots（QDs） sensitized TiO2 nanotube arrays photoelectrodes were investigated for their photovoltaic performance of quantum dots-sensitized solar cells. The highly ordered TiO2 nanotube arrays（TNAs） were synthesized on Ti foils by anodic oxidation method. Then CdS quantum dots were deposited onto the TiO2 nanotube arrays by successive ionic layer absorption and reaction（SILAR） method to serve as the sensitizers. Cd（NO3）2 and Na2S were used as the precursor materials of Cd＋ and S2- ions, respectively. It is found that the CdS QDs sensitizer may significantly increase the light response of TiO2 nanotube arrays. With increasing CdS QDs deposition cycles, the visible light response increases. Maximum photocurrent was obtained for the QDs that have an absorption peak at about 500 nm. Under AM 1.5 G illuminations（100 mW cm^-2）, a 4.85 mA/cm^2 short circuit current density was achieved, and the maximium energy conversion efficiency of the asprepared CdS QDs-sensitized TNAs solar cells was obtained as high as 0.81% at five SILAR cycles.

9－ANTHROIC ACID SENSITIZED PHOTOLYSIS OF DIPHENYLIODONIUM SALTS THROUGH INTRA－ION PAIR ELECTRON TRANSFER

We have studied 9-anthroic acid sensitized photolysis of dipbenyliodonius salts through fluorescence quenching, products analysis and Photo-CIDNP. The photoinduced electron transfer rate constant bas calculated to be 8.6×10 10/mol s. From photo-CIDNP study, both diphenyliodo and pbenyl radicals were confirmed as intermediates. Benzene is a cage escaped product from a singlet radical pair and diphenyliodonium Salt is a recombination preduct from a triplet radical pair.

A SENSITIZED PHOTOINITIATION SYSTEM ——BIS (7-DIETHYLAMINO COUMARIN ) KETONE-3 AND DIPHENYLIODONIUM SALT COMBINATION

Bis (7- diethylaminocoumarin) ketone- 3(DACK) and diphenyliodonium salt (DPIO)combination as an effective photoinitiation system for radical polymerization has been investigated. The sensitized photolysis of DACK/DPIO leads to bleaching of DACK and decomposition of DPIO to generate initiating radical species. The electron transfer sensitization occurs mainly from the triplet state of DACK. The photobleaching obeyed a second-order kinetics and the rate constant was evaluated to be 31.3mol^(-1)·1·s^(-1) Photopolymerization of MMA initiated by DACK/DPIO was carried out in acetonitrile solution. The polymerization rate was found to be proportional to the concentration of DACK, DPIO and MMA with the exponents of 0.34, 0.40 and 1.0 respectively. The initiated efficiency is comparable to those of small molecular ketones.The sensitized photoinitiation mechanism has been discussed.

Density Functional Theory Study on Organic Dye Sensitizers Containing Bis-dimethylfluorenyl Amino Benzofuran

The geometries, electronic structures, polarizabilities and hyperpolarizabilities, as well as the UV-Vis spectra of the two organic dye sensitizers containing bis-dimethylfluorenyl amino benzofuran were studied via density functional theory （DFT） and time-dependent DFT. The features of electronic absorption spectra were assigned on account of the agreement between the experiment and the calculations. The absorption bands in visible region are related to photoinduced electron transfer processes, and the dimethylfluorenyl amino benzo[b]furan groups are major chromophore that contributed to the sensitization of photo-to-current conversion. The role of vinylene group in geometry, electronic structure and spectra property is analyzed according to the comparative study of the dyes.

Sensitized Luminescence of Rare Earths

The enhancement effect on the fluorescence intensities of an Eu3+ (or/and Sm3+ )-thenoyltrifluoroacetone (TTA )-dibenzo-18-crown-6 (18-C-6 ) system and Eu 3+ (or /and Sm3+ ) -benzoyltrifluoroacetone (BTA )-cetyltrimethylammonium bromide (CTMAB) system by dysprosium has been studied. In the presence of enhancing ions, the fluorescence intensities of the above systems were enhanced by a factor of about 40-150, respectively. The above systems were used for the determination of europlum or/and samarium in rare earths oxides and gave satisfactory results.

Geometry, Electronic Structure, and Related Properties of Dye Sensitizer： 3,4-bis[1- （carboxymethyl）-3-indolyl]- 1 H-pyrrole-2,5-dione

The geometry, electronic structure, polarizability and hyperpolarizability of dye sensitizer 3,4-bis[1-（carboxymethyl）-3-indolyl]-1H-pyrrole-2,5-dione （BIMCOOH） were studied using density functional theory （DFT） with hybrid functional B3LYP, and the electronic absorption spectra were investigated using semi-empirical quantum chemical method ZINDO-1 and time-dependent DFT （TDDFT）. The results of natural bond orbital suggest that the natural charges of the dione, indole, and acetic groups are about 0.15e, -0.29e, and 0.44e, respectively. The calculated isotropic polarizability, polarizability anisotropy invariant and hyperpolarizability are 305.4, 188.3, and 1155.4 a.u., respectively. The electronic absorption spectral features in visible and near-UV region were assigned to the π→π^＊ transition due to the qualitative agreement between the experiment and the TDDFT calculations, and the transitions of the excited states 9-11 related to photoinduced intramolecular charge transfer processes. The analysis of electronic structure and UV-Vis absorption indicates that the indole groups primarily contributed sensitization of photo-to-currency conversion processes, and the interracial electron transfer between semiconductor TiO2 electrode and dye sensitizer BIMCOOH are electron injection processes from excited states of the dyes to the semiconductor conduction band.