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The gold colloidal nanoparticles was prepared by citrate reduction from chloroauric acid (HAuCl 4 ·4H 2 O). An ITO glass was coated with nanoporous TiO 2 , Fe 2 O 3 and ZnO by squeegee method. The squeezing coated films were loaded with Au-nanoparticles by depositing technique. The film was characterized by UV-visible transmittance absorption spectroscopy, SEM, XRD, XPS, and EDX techniques. The Pt counter electrode was prepared by a magnetron sputter method on an ITO glass. The semiconductor with Au-loaded film was used as a working electrode whereas Pt film was used as a counter electrode in a solar cell. The charge was separated by short circuit current and an open circuit voltage and the cell efficiency was measured by IPCE analyzer. The comparative photocurrent-performance of different semiconductors loaded with Au-nanoparticles was analysed. Au@TiO 2 , Au@Fe 2 O 3 , Au@ZnO were found to be suitable films for photo-current production having a good efficiency with Au@TiO 2 as the best of the three. © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v5i2.13391 J. Sci. Res. 5 (2), 245-254 (2013)

Fe 3 O 4 –TiO 2 core-shell nanocomposites were successfully prepared and characterized by FE-SEM, XRD, UV–vis absorbance spectra, and EDX. The FE-SEM and EDX studies revealed core-shell structure with a particle size of ca. 40–50 nm. We adopted HeLa cells as a model to investigate the thermal-photocatalytic cell killing efficiency of Fe 3 O 4 –TiO 2 using 150 μg/mL dose content for 10 min exposure time. We found neither only AC magnetic-field induction nor only photoirradiation condition could kill the cancer cells up to satisfactory level using Fe 3 O 4 –TiO 2 nanocomposites. Finally, the results revealed that almost 100% cancer cells were destructed by Fe 3 O 4 –TiO 2 nanocomposites whereas for bare Fe 3 O 4 and bare TiO 2 , 90% and 56% cancer cells were killed, respectively, under combined AC (alternating current) magnetic-field induction and UV–vis photoirradiated conditions.

Garlic (Allium sativum) is a herb that is used mainly as a food in many countries for its medicinal properties since ancient times. It enhances immune functions and has antibacterial, antifungal, antivirus and anticancer activities. Organosulfur compounds originating from garlic inhibit carcinogen activation. In this study we prepared aqueous garlic extract (AGE) and its in vitro application to cancer (HeLa) cell line was performed to observe the cancer cell killing efficacy. Different concentrations of AGE like 100, 200, 300, 400, and 500 µL per a 5-mL minimum essential medium solution were used for treatment. The results revealed that 95% cancer cells were destructed in a dose of 500 µL, whereas about 92, 87, 60, and 24% cancer cells were destructed in a dose of 400, 300, 200 or 100 µL of AGE, respectively.Keywords: Aqueous garlic extract; Cancer cells; Cytotoxicity; Anticancer activity.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i2.6557 J. Sci. Res. 3 (2), 375-382 (2011)

In this article, we have reported self-assembled synthesis of pore tunable, mesoporous ZnS microsphere and its photocatalytic activity. The photocatalytic activity was evaluated using Methyl Orange (MO) as model pollutant under UV light irradiation. The mesoporous photocatalysts was synthesized using hydrothermal method without using any templates or catalysts in large scale. The products were characterized by field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectrometry (EDX). The nitrogen adsorption analysis confirmed the presence of mesoporous structure. The pore size of the photocatalysts could be enlarged from 2.6 to 7.2 nm by changing the concentration of the zinc precursor. The microsphere formation has been facilitated by self-assembly followed by Ostwald ripening process. In conclusion, this simple synthetic methodology open new vistas to prepare mesoporous photocatalysts in large scale.

Without using an external precursor a simple and one-step method for the synthesis of C-doped TiO 2 submicrospheres has been developed via hydrolysis of titanium tetraisopropoxide in pure methanol followed by calcination under air at 500 °C. Also, with the addition of d -glucose and NH 4 OH solution during the hydrolysis process, C- or N-doped and C, N co-doped TiO 2 submicrospheres can be prepared by the same method. The size of the submicrosphere was homogeneous ranging from 300 to 400 nm. The resulting submicrospheres were characterized by FE-SEM, TEM, XRD, XPS and UV–vis diffuse reflectance spectroscopy. The C- or N-doped and C, N co-doped submicrospheres showed obvious absorption in the wavelength up to around 650, 500 and 650 nm, respectively. The activity of the photocatalysts was evaluated by the hydroxyl radical formation under visible light irradiation. Finally, the mechanism of sphere formation is discussed.

The metallic Cu nanoparticles have been successfully deposited on the heterogeneous TiO2 surface by the borohydride reduction of copper nitrate in water/CH3CN mixture under Ar atmosphere. The catalytic activity of the Cu–TiO2 nanocomposite was evaluated by the application to a photocatalytic cancer cell-killing under UV–visible light irradiation. Based on the obtained results, a plausible mechanism was proposed.

A new type of solid state solar cell is produced by using Fe 2 O 3 (working electrode) and SiC as a hole collector (counter electrode). Two molten salts , 1-ethyl-3-methylimidazolium chloride (EMICl) and 1-butyl-3-methylimidazolium iodide (BMII) were used as crystal growth inhibitor s with a SiC film. It was found that BMII shows about 10 times higher efficiency compared to an EMICI - based SiC film solar cell. Keywords: Fe 2 O 3 ; SiC; Solid state solar cell; Molten salt. © 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i1.2660 J. Sci. Res. 2 (1), 1-8 (2009)

The relation among the change of the crystal structure, the amount of doped N and the photocatalytic activity for the decomposition of methylene blue was studied. The N-doping was promoted by the change of the crystal structure from the rutile phase to the anatase phase. The photocatalytic activity for the decomposition of methylene blue was enhanced by an increase in the amount of anatase crystals and doped N. Keywords: Laser ablation; N-doping process; Crystal change; N-doped TiO 2 thin film; Dye decomposition. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i1.2992 J. Sci. Res. 2 (1), 17-23 (2010)

High-quality, well-crystallized, single-crystal, wurtzite CdS hexagonal microtowers (with and without tubular structure) and CdS with octahedral geometry were successfully synthesized by tuning the solvent ratio of water and ethanol for the first time on a large scale without using any catalysts or templates. The products were characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectrometry, transmission electron microscopy, and field emission scanning electron microscopy. CdS with microtowers, octahedral geometry, and hexagonal plates was formed by thermal decomposition of cadmium thiocyanate at 400 °C under open atmospheric conditions. The influence of solvent, initial precursor concentration, decomposition temperature, and time on the morphology of CdS was investigated, and the results were discussed. The XRD results showed that the cadmium thiocyanate complex is completely decomposed into CdS at 300 °C for 2 h and the wurtzite phase was formed under all experimental conditions, which ope...

Laser-deposited Fe 2 O 3 films or dye-fixed TiO 2 films were prepared for solar cells. For both the cells, a single walled carbon nanotube (SWNT) film or a Pt-loaded SWNT film, prepared by simply pasting over ITO glass, was used as a counter electrode. Stable current ( I )-voltage ( V ) curves were found under UV-visible light irradiation using water containing KI and I 2 as an electrolyte. A comparison of I-V curves was made for Pt alone and SWNT alone films used as a counter electrode. Almost similar efficiency was found by using both types of counter electrodes. However, enhanced efficiency was obtained for the Pt-loaded SWNT-film counter electrode. Keywords : TiO 2 ; Fe 2 O 3 film; Solar cell; SWNT. © 2009 JSR Publications. ISSN: 2070-0237(Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v1i3.2631 J. Sci. Res. 1 (3), 430-437 (2009)

A new N, C codoped visible light responsive hierarchical porous ZnS photocatalysts have been successfully synthesized by using a simple procedure in large scale without using catalyst or template. This is a first example of a nonmetal doped sulfide semiconductor photocatalyst working under visible light irradiation. N, C codoped ZnS catalysts were formed by thermal decomposition of zinc isothiocyanate at 300, 400, and 500 °C under open atmospheric conditions. The influences of various experimental conditions on the morphology of the catalysts have been investigated. The synthesized catalysts were characterized by the required analytical techniques. The N, C codoped catalysts possess well-crystallized wurtzite structure and have excellent visible light absorption when compared to undoped ZnS. Elemental and XPS analyses confirmed the presence of both nitrogen and carbon elements in ZnS. The chemical natures of nitrogen and carbon have been discussed on the basis of FTIR and XPS results. The visible light in...

Laser irradiation of copper(II) tetrasulfonated phthalocyanine (CuTsPc) microcrystals in poor organic solvents such as methanol, 2-methyl-2-propanol, ethanol, tetrahydrofuran, and acetone has produced CuTsPc nanoparticles with 15–112 nm in diameter. Field emission scanning electron microscopy (FESEM) images have shown the formation of CuTsPc nanoparticles in poor organic solvents used in this work. The mean diameters of CuTsPc nanoparticles obtained from transmission electron microscopy (TEM) images in methanol, 2-methyl-2-propanol, ethanol, tetrahydrofuran, and acetone were determined to be 26, 36, 35, 86, and 78 nm, respectively. A correlation between the size of CuTsPc nanoparticles and a solvent polarity could be found in this work.

The bilayer thin film composed of graphite silica (GS) and TiO 2 was prepared by the laser ablation technique. The properties of the thin films considerably depended on the laser ablation conditions such as gas pressure and substrate temperature in a chamber. The laser ablation of GS caused complete disappearance of the quartz XRD (X-ray diffraction) peaks in GS. The GS loading, especially at a thickness of around 200 nm, led to significant enhancement in the photocatalytic activity of the TiO 2 thin film for the hydrogen production and the methylene blue decomposition in spite of the destruction of the quartz crystal in GS.

N-doped TiO2 thin films were prepared by the laser ablation method under an N2 gas atmosphere. Properties of the films such as color, the relative amount of N doped and the crystal structure strongly depended on substrate temperature and N2 gas pressure. XPS data indicated that the amount of doped N unexpectedly increases with decreasing N2 gas pressure in the range of ca. 40–270 Pa. We proposed that the N-doping occurred when N species and TiO2 particles collide on the substrate. The decomposition of methylene blue using the N-doped TiO2 thin film was also performed under visible light irradiation.

The effect of carbon nanotubes on TiO2, for the photocatalytic H2 gas production from water/alcohol mixtures, was investigated. The drastic synergy effect was found with an increase in the amount of H2 gas by a factor of ca. 400 simply by mixing single walled carbon nanotubes (SWNTs) with TiO2. A comparison between SWNTs/TiO2 and Pt/TiO2 mixtures was made for the amount of H2 gas produced. Based on the observed results, a plausible mechanism was proposed.

Photocatalytic hydrogen production from methanol aqueous solution containing mixture of titanium dioxide (TiO 2 ) and graphite silica (GS) was enhanced by laser ablation in liquid. It was found that the amount of hydrogen gas evolved in lased GS–TiO 2 was less than that in raw GS–TiO 2 mixture. However, the amount of hydrogen gas with the mixture of raw TiO 2 and lased GS was two times as large as that of the raw GS–TiO 2 mixture. This enhancement effect may be attributed to increase in the reaction surface area by the fine-subdivided GS particles and the aggregation of lased GS and raw TiO 2 .

The photocatalytic production of hydrogen gas from aqueous methanol solution was performed using powdered mixtures of graphite silica (GS) and platinized TiO 2 (Pt/TiO 2 ) or those of GS, Pt and TiO 2 . The addition of GS to Pt/TiO 2 resulted in the decrease of the amount of H 2 gas, whereas the addition of GS to mixtures of TiO 2 and Pt led to the incremental production of H 2 gas. This effect is attributed to the aggregation of GS, TiO 2 and Pt in suspension. The new additional electron transfer process of TiO 2 → Pt → GS caused the increment of the amount of hydrogen gas.

Hydrogen production was performed under visible-light and combined UV/visible-light irradiation by using a system consisting of cobalt(II)tetraphenylporphyrin (CoTPP), methylviologen (MV2+), ethylenediaminetetraacetic acid disodium salt and Pt-loaded poly( l -glutamate) (Poly(Glu)) in aqueous decylammonium chloride (DeAC) solution. CoTPP was solubilized in hydrophobic clusters of DeAC induced by its cooperative binding to Poly(Glu). About 0.15 and 3.5 μmol of hydrogen gas were obtained after irradiation for 3 h using visible-light and combined UV/visible-light, respectively. The rate of hydrogen evolution depended on the change in the conformation of Poly(Glu) induced by the cooperative binding with DeAC. An electron was transferred from CoTPP to MV2+ in the Poly(Glu)–DeAC complex system via the singlet state, finally resulting in the hydrogen evolution.

Hydrogen production was accomplished under visible-light irradiation by using a system consisting of a biomolecule (chlorophyll a), methylviologen, ethylenediaminetetraacetic acid disodium salt and Pt-loaded poly(l-glutamate) (Poly(Glu)), in aqueous decylammonium chloride (DeAC) solution. Spectroscopic studies revealed that chlorophyll a is solubilized in the hydrophobic clusters of Pt-loaded Poly(Glu)-decylammonium chloride. In the Poly(Glu)-DeAC complex, the electron transfer occurred between chlorophyll a and methylviologen leading to hydrogen production. The most noticeable result is that the rate of hydrogen evolution depends on the change from the random coil to the alpha-helix in conformation of Poly(Glu) induced by the cooperative binding with DeAC.

The photocatalytic production of hydrogen gas from water–methanol mixtures was performed in contact with a suspended mixture of powdered titanium dioxide (TiO2) and graphite silica (GS), a naturally available mineral. A drastic synergy effect for hydrogen production was found for GS in collaboration with TiO2. The amount of hydrogen gas evolved from water–methanol mixtures was increased by a factor of ca. 100 simply by mixing GS with TiO2. The synergy effect is attributed to the enrichment of hydrogen ions in the clay components of GS and aggregation of GS and TiO2 particles.

Hydrogen production was performed under visible light irradiation by using a system consisting of cobalt(II)tetraphenylporphyrin, methylviologen, ethylenediaminetetraacetic acid disodium salt and Pt-loaded poly( l -glutamate) (Poly(Glu)) in aqueous decylammonium chloride (DeAC) solution. The rate of hydrogen evolution depended on the change in the conformation of Poly(Glu) induced by the cooperative binding with DeAC.

It was proved that the analysis of deuterium can be conducted using laser-induced plasma spectroscopy. By selecting the appropriate surrounding gas, its pressure, and gating time of the detection system, it was shown that the emission lines of both hydrogen (H(alpha)) and deuterium (D(alpha)), separated by only 0.179 nm, can be fully resolved. A linear calibration curve was also obtained, indicating that this technique has the potential for quantitative analysis of deuterium. The minimum detection limit achieved in this stage of research was estimated to be 50 ppm. We have also shown that this technique can be used as a simple and rapid method for D and H analysis in solid samples.

Rose-type magnetic nanoplates (RTMNPs) were synthesized by a simple hydrothermal decomposition method where FeCl 2 ·4H 2 O was solely used as a precursor. The synthesized nanoplates were characterized using XRD, FE-SEM, UV–vis absorption (reflectance) spectra and magnetic hysteresis loops. The resulting nanoplates were in the ranges of size 350–500 nm and width 60–70 nm with high crystallinity, purity (shown by XRD) and reproducibility. These iron oxide nanoplates have a great potential in magnetic nanodevices and biomagnetic applications.

A wet-type solar cell based on Fe2O3 films prepared by the laser ablation method was investigated. The performance was increased drastically by the thermal treatment of the Fe2O3/FTO films. This enhancement effect is caused by the improvement of the binding interface between FTO and Fe2O3. Keywords: Fe2O3/FTO film, Thermal treatment, Laser ablation, Wet-type solar cell

Copper nanoparticles were successfully synthesized by the borohydride reduction of copper nitrate salt in water/CH 3 CN mixed solvent under inert argon-purged conditions. Cu nanoparticles were synthesized in large-scale production for the first time by introducing CH 3 CN into water and preventing oxidation during the preparation of nanoparticles. Nanoparticles were characterized by using UV–visible absorption spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques. High resolution TEM pictures showed the formation of homogeneous cubic-structured copper nanoparticles with sizes less than 100 nm. This new kind of synthesis method shows the excellent stability compared with that of citrate-protected copper nanoparticles, which may provide an efficient way to improve the fine tuning of the structure and size of copper nanoparticles.

Potentiometric and spectroscopic studies of a chlorophyll a (Chl)−copolypeptide of l-ornithine and l-tyrosine (poly(l-Orn, l-Tyr)) system in aqueous solutions of sodium dodecyl sulfate (SDS) were carried out. The cooperative binding of SDS to poly(l-Orn, l-Tyr) studied by the potentiometric measurement of the binding isotherm showed that coil to α-helix transition of the poly(l-Orn, l-Tyr)−SDS complex takes place with an increase in SDS concentration. An increase in the helix content of poly(l-Orn, l-Tyr)−SDS complex can be well interpreted in terms of the hydrophobic interaction among bound SDS ions. On the basis of theoretical analysis of the cooperative binding isotherm, it was concluded that the formation of a micelle-like cluster consisting of at least seven SDS ions is required for the stabilization of a surfactant-induced helical structure. Singlet excitation energy transfer between l-Tyr-containing copolypeptide and Chl was investigated with steady-state fluorescence spectroscopy, and the efficien...

Spectroscopic and potentiometric studies of chlorophyll a (Chl)-copolypeptide of L-ornithine and L-tyrosine (poly (L-Orn, L-Tyr)) complexes in an aqueous surfactant solution indicate that Chl molecules are incorporated into poly (L-Orn, L-Tyr)-surfactant complexes accompanying a conformational change from a random coil to α-helix and a conformation-dependent energy transfer effectively occurs from the L-tyrosine residue to Chl in the Chl-copolypeptide-surfactant system.

Pyrene was adsorbed to a TiO 2 surface from water–alcohol mixture solutions at 25 °C and pyrene–TiO 2 particles were recovered by filtration. We found that the surface of TiO 2 thus recovered is relatively hydrophobic and pyrene is not decomposed but keep its fluorescence characteristics on the spectral measurement under ultraviolet excitation.

Magnetite (Fe3O4) nanoparticles were prepared by co-precipitation and hydrothermal methods and their phase transfer was done successfully to compare their performances in different aspects. Synthesized nanoparticles were characterized for XRD, FE–SEM, TEM, UV-Vis absorption (reflectance) spectra, magnetic hysteresis loops and a.c. magnetic field induced hyperthermia. The magnetic nanoparticles prepared by the co-precipitation method show superior performances in respect of heat dissipation capability, saturation of magnetization values and particle size when compared to those prepared by the hydrothermal method.

Gold colloidal nanoparticles were prepared by the liquid laser ablation of a gold metal plate in water and also by the citrate reduction of HAuCl(4).4H2O. The gold colloidal nanoparticles with the plasmonic band strongly absorb light, which is converted to the photothermal energy. This photothermal energy gives a cytotoxic effect on epithelial carcinoma cells. Interestingly, we found that the size and shape of the nanoparticles are changed by light during the photothermal process in vitro. The cervical carcinoma cell line (HeLa cell) was incubated with the colloidal gold nanoparticles and then exposed to continuous visible light at 400-600 nm with UV- and heat-cutoff filters. The distinct cell-killing effect was observed by this procedure. In the absence of the gold colloidal nanoparticles, only a small amount of cells were photothermally destroyed.

An enhanced quenching of fluorescence of chlorophyll a by methylviologen in methanol solution was found to proceed via both dynamic and static processes. It was shown that the formation of a ground-state “dark” complex between the reactants is responsible for the latter process.

Dye-fixed TiO2 films and doubly layered Fe2O3 films were prepared and used in solar cells. For the both cells a single walled carbon nanotube (SWNT) film, prepared by simply pasting over ITO glass, was used as a counter electrode. A stable current (I)-Voltage (V) curve was found under UV-visible light irradiation using KI+I2 in water as an electrolyte. A comparison of I–V curves between Pt and SWNT films has been made. Under UV visible light irradiation almost similar results were found for both Pt and SWNT films. In the case of Fe2O3, the open circuit voltage was found to be low (about 90 mV) but the short circuit current was found to be comparatively high (about 0.75 mA cm/t-2) whereas those for the Eosin Y (EY)-fixed TiO2 film with the SWNT film as a counter electrode, were found to be 350 mV and 0.27 mA cm/t-2, respectively.

水-有機溶媒混合溶液中でのクロロフィルa(Chl)と両親媒性アミドであるN-methylmyristamide(NMMA)の相互作用を吸収,蛍光.共鳩ラマン分光法を用いて調べた。アルコール類やアセトンのような有機溶媒に水を適量添加すると,687nm(吸収)および687nm(蛍光)にCh1とNMMAの相互作用に基づくマーカー一パンドを観測することができた。この結果はCh1とNMMAの会合体が形成されていることを強く示唆している。一方,水-ピリジン,水-テトラヒドロフラン混合溶液中ではCh,1とNMMAの相互作用は認められなかった。相互作用についてより詳細な知見を得るために,水一有機溶媒溶液中でのCb1-NMMA系の共鳴ラマンスペクトルを測定したところ,ChlとNMMAの相互作用に基づくマーカーバソドを1215cm-1に見いだすことができた。またその相互作用は水の含量が45～60vo1%(水一メタノール系),60～70マol%(水-エタノール系),80～90vo1%(水-1-プロパノール系),50～80vol%(水-アセトン系)の狭い範囲で起こっていることがわかった。そこで,水-有機溶媒混合溶液にClausius-Mosottiの式を適用して分子誘電分極の値を見積ったところ,有機溶媒の種類に依存せず19～27cm3の範囲にあった。これは,Ch1とNMMAの相互作用を誘引する一つの因子として分子誘電分極が重要な働きをしていることを示している。

Spectroscopic studies were carried out on chlorophyll a and cobalt(II)tetraphenylporphyrin solubilized in a poly( l -glutamate) (Poly(Glu))-decylammonium chloride (DeAC) complex system, in the presence of methylviologen (MV2+). The cooperative binding occurred between the anionic Poly(Glu) and the cationic DeAC, leading to the formation of micelle-like hydrophobic clusters of DeAC and also the change in conformation of the Poly(Glu) from the random coil to the α-helix. All of the absorption spectra, the fluorescence quantum yields and the fluorescence lifetimes indicated the existence of equilibrium between the aggregated biofunctional molecules in the bulk phase and the monomeric species in the complex phase of the Poly(Glu)–DeAC solution. The fluorescence quenching of the biofunctional molecules by methylviologen indicates that the conformation-dependent electron transfer occurs in the complex phase.

The photocatalytic hydrogen production from aqueous solutions of two diacids, i.e., oxalic acid and fumaric acid, was performed using the mixtures of TiO

Cu–TiO2 nanocomposites with different Cu/TiO2 molar ratios were synthesized by a new simple chemical reduction method. The morphological structure and the surface species of Cu–TiO2 nanocomposites ...

The photocatalytic production of hydrogen gas from water–methanol mixtures was performed in contact with a suspended mixture of titanium dioxide (TiO2) and graphite silica (GS), one of natural mine...

Magnetic nanocubes, with a controlled precursor molar concentration of ferric nitrate fixed at 0.004 M to ferrous chloride ranging from 0.002 to 0.01 M, were synthesized by a new simple colloidal method at 60 °C under 1 M alkaline condition. The metallic Au-ultrathin layer was successfully functionalized on the magnetic nanocubes surface for the fabrication of the core–shell structure (Fe3O4@Au) by the borohydrate reduction of HAuCl4 in water/poly-L-histidine solution. The functionalized core–shell structure with varying molar-ratios of Fe3+/Fe2+ in aqueous media, core–shell structural characteristics (for example, size, morphology, and shell thickness), and physical properties (for example, crystalline, electronic, optical, and magnetic ones) of the resultant functional nanocubes were systematically investigated using UV-visible spectroscopy, SEM, TEM, XRD, XPS, EDX, and superconducting quantum interface device (SQUID) magnetometer analysis. The core–shell structure of Fe3O4@Au exhibits plasmonic properties with high magnetization and showed excellent hyperthermia-photothemal activity towards the cancer cell (HeLa) killing. For the hyperthermia killing of cancer cells under the alternating current magnetic field (AMF), the as-prepared Fe3O4 exhibited higher activity than the Fe3O4@Au nanoparticles. Interestingly, under the simultaneously combined AMF and photoirradiation with Fe3O4@Au, much higher cancer cell killing was found than with only AMF induced hyperthermia killing. The promoting effect of an Au-ultrathin shell supported on Fe3O4 showed strong absorption in the visible region due to localized surface plasmon resonance and increased the hyperthermia-photothermal temperature with the photothermal stability of the Fe3O4@Au nanoparticles, rather than only Fe3O4. It was found that the cell killing activity depends on the optical and magnetic properties of the Fe3O4@Au nanocubes. The optical and magnetic properties depended on the molar-concentration ratios of precursors of Fe(NO3)3·9H2O and FeCl2·4H2O. The synthesized Fe3O4@Au nanocubes have great potential for a combination of cancer imaging and local treatment as a cancer cell killing paradigm of “see and treat” applications.

In this current study we synthesized mixed α and γ-Fe2O3 nanoparticles and their synergistic toxic effect against HeLa cells was investigated under ac (alternating current) magnetic-field induction and photoirradiation conditions at room temperature. The experiment was designed to find out the cancer cell killing efficacy of as-synthesized bare γ-Fe2O3, bare α-Fe2O3 and mixed α and γ-Fe2O3 nanoparticles under combined ac magnetic-field induction and photoirradiation conditions. The toxic effect of nanoparticles was obtained by counting the percentage of viable cells after all the treatments were completed using various concentrations. The results revealed that the highest toxic effect was obtained using mixed α and γ-Fe2O3 nanoparticles under combined ac magnetic-field induction and photoirradiation conditions at a dose of 60 μg mL−1 MEM (minimum essential medium), i.e., approximately 98% cancer cells were killed, whereas under only ac magnetic-field induction or only photoirradiation conditions, only 89% and 66% cancer cells were destroyed using the same dose of same nanomaterials, respectively. We also noticed that 55% and 79% cancer cells were destroyed using bare α-Fe2O3 and bare γ-Fe2O3 nanoparticles, respectively, under combined ac magnetic-field induction and photoirradiation conditions using the same dose. To the best of our understanding, the mechanism or reason for almost 100% HeLa cell killing under the combined conditions can be ascribed to the combined or additive effect of ac magnetic-field induced hyperthermia and photocatalytic cytotoxicity.

Fe-doped TiO2 nanopowders with controlled molar-atomic ratios of iron to titanium oxide (in percentage) ranging from nominal 1 to 10% were synthesized by a new simple sol–gel method. Metallic Ag nanoparticles were successfully deposited on the nanopowder of the Fe-doped TiO2 surface by citrate reduction of AgNO3 in water/CH3CN mixture. The molar ratio of iron to TiO2, phase formation, bandgaps, crystallinity, catalytic and plasmonic properties of the resultant composites were systematically investigated using UV-visible spectroscopy, SEM, TEM, XRD, XPS, EDX, and photoluminescence spectral analyses. The photocatalytic activity of Ag@Fe-doped TiO2 composite nanoclusters was evaluated through photocatalytic killing of cancer cells. For the photocatalytic killing of cancer cells under visible light irradiation, as-prepared Ag@Fe-doped TiO2 nanopowders exhibited higher activity than Fe-doped TiO2. The promoting effect of the Ag nanoparticles deposited on the Fe-doped TiO2 surface showed strong absorption in the visible region due to localized surface plasmon resonance of Ag and inhibited the recombination of photoelectrons and holes rather than only Fe-doped TiO2. The cytotoxic cell killing efficiency depends on the molar ratio of Fe content to TiO2. The optimum Fe content in Fe-doped TiO2 was determined to be 5% due to the Fe/TiO2 molar ratio. Based on the obtained results, a plausible mechanism was also proposed.

Novel neck-structured Fe 3 O 4 , γ-Fe 2 O 3 and α-Fe 2 O 3 magnetic nanoparticles were successfully prepared by a modified hydrothermal method. Ferrous chloride tetrahydrate was solely used as a precursor for the novel nanomaterials. The X-ray diffractometric study revealed the purity of the nanomaterials thus synthesized. All of the products were characterized using a field-emission scanning electron microscope (FE-SEM) and a transmission electron microscope (TEM) for the particle size and morphology. Neck-structured particle morphology was observed for the first time in all of iron oxides with magnetic properties. The particle size observed was 50–60 nm. The synthesized nanomaterials showed excellent magnetization values when magnetic hysteresis loops were measured using a superconducting quantum interference device (SQUID). Moreover, the as-prepared magnetic nanoparticles suspensions showed significant temperature increments under an AC (alternating current) magnetic-field induction condition at room temperature which indicates the hyperthermia feasibility. Keywords: Magnetic materials; Neck-structured; Hyperthermia; Heat dissipation. © 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v4i1.8727 J. Sci. Res. 4 (1), 99-107 (2012)

Au nanoparticles were prepared by a chemical reduction method and were deposited on TaON nanoparticle or BiOI microsphere to prepare the composites of Au/TaON or Au/BiOI, respectively. The composites of Au/TaON and Au/BiOI were analyzed by UV-visible spectroscopy, XRD, and EDX. The films of these nanocomposites were prepared by a squeeze method and were applied to solar cell where Pt film was used as counter electrode. A water based solution of Ce 3+ /Ce 4+ was used as an electrolyte. It was found that Au deposited TaON or BiOI film shows higher current ( I )-voltage ( V ) curve under UV-visible light irradiation. Key words: Au; TaON; BiOI; Composite; S olar cell . © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i3.5000 J. Sci. Res. 2 (3), 413-417 (2010)

A simple and fast synthesis method of gold and silver nanoparticles without any surfactant or reducing agent has been developed by using the extract of green tea ( camellia sinensis ) under microwave irradiation. The synthesized gold and silver colloidal nanoparticles were spherical in shape and have an average diameter of 13 and 17 nm for Au and Ag nanoparticles, respectively . The as-synthesized nanoparticles were characterized by TEM, XRD, XPS, and UV-visible spectroscopy. Keywords: Microwave; Gold; Silver; Nanoparticles; Biosynthesis. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i3.4993 J. Sci. Res. 2 (3), 495-500 (2010)

Nitrogen and carbon codopants-stabilized hierarchical porous ZnS microspheres undergo an unexpected dynamic transformation into hollow microspheres when nitrogen and carbon are removed from the former. Thus, such a transformation is evidence for the unprecedented stability of non-metal doped visible light-responsive photocatalysts.

A series of measurements have been performed on the time dependences of the intensities of helium, hydrogen, and deuterium emission lines from the corresponding laser-induced helium plasma at atmospheric pressure for two different He flow rates. The prolonged Hα and Hβ emissions along with their constant intensity ratio over a relatively extended period indicate the need to provide an alternative excitation mechanism other than the well-known thermal excitation process in a hot plasma. This additional excitation mechanism is also related to the metastable excited state of a He atom as indicated by the similar characteristics of the observed time dependence of the emission intensities. The enhanced intensity and lifetime of He emission at a high He flow rate was explained in terms of the collision-induced increase in the number of He atoms excited to above the 2 S10 metastable state, which was also responsible for the delayed excitation of H and D atoms via an energy transfer mechanism involving a Penning-...

The local mole fraction of an alcohol such as methanol, ethanol, and 1-propanol was determined on the basis of the polarity variation sensed by pyrene in water-alcohol binary mixtures. The data indicate that alcohol molecules preferentially solvate pyrene in water; the degree of preferential solvation increases with an increase in the extent of the hydrophobic interaction between pyrene and alcohols.

An experimental study on gas analysis by means of laser-induced breakdown spectroscopy was conducted using a Nd-yttrium aluminum garnet laser (1,064 nm, 120 mJ, 8 ns) and helium host gas at atmospheric pressure on a sample of mixed water (H2O) and heavy water (D2O) in vapor form. It was shown that completely resolved hydrogen (Hα) and deuterium (Dα) emission lines that are separated by only 0.179 nm could be obtained at a properly delayed detection time when the charged particles responsible for the strong Stark broadening effect in the plasma have mostly disappeared. It is argued that the helium metastable excited state plays an important role in the hydrogen excitation process.