bluuebunny/crossref_metadata_2025_split huggingface dataset:
Finding a Facile Method to Synthesize Decahedral Silver Nanoparticles through a Systematic Study of Temperature Effect on Photomediated Silver Nanostructure Growth
Authors: Lee Yao‐Chang , Chen Sin‐Jia , Huang Cheng‐Liang 
Published: May 2015

AbstractTo the best of our knowledge, few reports have been concerned with the effect of temperature on photomediated silver nanostructure growth. In this work, the shape evolution from spherical silver nanoparticles to silver nanoprisms and nanostructures in other shapes under the irradiation of a sodium lamp (λmax = 589 nm, 0.66 W/cm2) at various temperatures (i.e., 15, 40, 60, and 80 °C) were studied by recording the TEM images and time‐course UV‐vis‐NIR spectra of the silver colloids. From TEM and spectra analysis, it was found that the photomediated silver nanoparticle shape conversion process would be faster at a higher temperature, i.e., ca. 2 hours at 80 °C, and slower at a lower temperature, i.e., ca. 17 hours at 15 °C. The silver nanoplates synthesized at a higher temperature had a narrower size distribution and were thicker than those synthesized at a lower temperature. Some decahedral silver nanoparticles, about 10% of the final irradiation products, were observed in the synthesis (with a sodium lamp) at 15 °C. In order to produce a higher yield of decahedral silver nanoparticles, the sodium lamp was replaced with blue LEDs (λmax = 450 nm), which have a wavelength closer to the SPR of decahedral silver NPs (ca. 490 nm). The decahedral silver nanoparticles with a fairly narrow size distribution were obtained by irradiating the spherical nanoparticle colloids with the blue LEDs at 2 °C in the absence of PVP or other large‐molecular‐mass surfactants.
Development and Validation of Ropinirole Hydrochloride and its Related Compounds by UPLC in API and Pharmaceutical Dosage Forms
Authors: Krishnaiah CH , Murthy M. Vishnu , Reddy A. Raghupathi , Kumar Ramesh , Mukkanti K. 
Published: May 2015

AbstractA novel stability‐indicating gradient reverse phase ultra performance liquid chromatographic (RPUPLC) method was developed for the determination of purity of Ropinirole in presence of its impurities and forced degradation products. The method was developed using Waters Aquity BEH 100 mm, 2.1 mm, 1.7 μm C‐8 column with mobile phase containing a gradient mixture of solvent A and B. The eluted compounds were monitored at 250 nm. The run time was within 4.5 min which Ropinirole and its four impurities were well separated. Ropinirole was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. Ropinirole was found to degrade significantly in oxidative and base stress conditions and stable in acid, water, hydrolytic and photolytic degradation conditions. The degradation products were well resolved from main peak and its impurities, thus proved the stability indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. This method was also suitable for the assay determination of Ropinirole in pharmaceutical dosage forms and dissolution studies.
A Comparative Investigation on Efficacy of Two Methodologies of Solid Phase Extraction for Separation and Pre‐Concentration of Trace Copper in Aqueous Samples Prior to Flame Atomic Absorption Spectrometric Determination
Authors: Noei‐Aghaei Mohammad Amin , Mohammadhosseini Majid , Zamani Hassan Ali , Nekoei Mehdi 
Published: May 2015

AbstractThis report describes the capability of two facile, sensitive and concentrative methods for quantification of sub‐ppm levels of copper in different solutions using octadecyl silica bonded phase membrane (OSPM) disks. The first standpoint is based on introduction a homogenized miscellaneous solution of copper‐1‐(2‐pyridylazo)‐2‐naphtol (PAN) to the surface of an OSPM disk. The second perspective is the usual manner and is performed by impregnation or modification of the sorbent surface. All the affecting experimental variables such as pH, amount of modifier, eluent type, concentration of each metal and ligand, surfactant type, sample and eluent flow‐rate, time and disk capacity are also tested. The results reveal that the first way is considerably more time consuming. However, the second method possesses high break‐through volume (2000 mL) and lower detection limit (0.01 ng mL−1). Both the methods have been successfully applied for isolation and determination of trace copper in different aqueous and real samples.
Bio‐Orthogonal Protein Labeling Methods for Single Molecule FRET
Authors: Chang Wei‐Hau , Liu Yuhua 
Published: May 2015

AbstractSingle‐molecule fluorescence resonance energy transfer (smFRET) has emerged as a powerful technique for visualizing the dynamics and architecture of proteins, multi‐subunit protein complexes, or protein‐nucleic acid complexes. To suffice a FRET study, selective labeling with a pair of a donor dye and an acceptor dye is required, with the two dyes on two sites on a protein, or with the donor on one protein sub‐unit while the acceptor on another subunit, or with the pair divided between protein and DNA (RNA). Due to the availability of orthogonal chemical moieties, most biophysicists armed with single FRET have been limited to the processes of nucleic acids metabolism by studying protein‐DNA (‐RNA) interactions. Nevertheless, diverse biological processes usually involve communications between proteins. Indeed, protein‐protein interactions constitute fundamental questions regarding intra‐ and intercellular signal transduction and are under intensive research, yet mainly by conventional methodologies. In this review, various bio‐orthogonal methods recently developed for labeling proteins via protein domains, small peptides, or single amino acids are examined. These approaches comprise a repertoire that overcomes the challenges of labeling two sites on a protein or a protein complex to facilitate the investigation of protein‐protein interactions by the modern single molecule FRET method.
Efficient Energy and Electron Transfer between Donor and Acceptor Chromophores in Aluminophosphate Hybrid Materials
Authors: Lo Chih‐Yuan , Chen Chih‐Hsien , Tsai Tim W. T. , Zhang Long , Lim Tsong‐Shin , Fann Wunshain , Chan Jerry C. C. , Luh Tien‐Yau 
Published: May 2015

AbstractThe first organic‐inorganic hybrid materials (OIHMs) having one or a combination of two chromophores in different ratios are obtained from the aryl phosphonic acid and aluminum lactate via sol gel process. The structures of these OIHMs are analyzed by the 27Al and 31P NMR. The fluorescence resonance energy transfer (FRET) as well as photoinduced electron transfer (PET) between donor and acceptor chromophores in these hybrid materials have been investigated and the efficiencies can be up to 97 and 93%, respectively.
Molecular Switching in Nanospaces
Authors: Dube Henry , Durola Fabien , Ajami Dariush , Rebek Julius 
Published: May 2015

AbstractSwitching devices that operate on the molecular level lie at the heart of nanomachinery. The energies involved range from scores of kcal/mol during cleavage or formation of covalent bonds to a few kcal/mol when the signals are changes in conformation. Here we examine three systems that use light, metal/ligand binding, and acid/base chemistry as switching devices to transfer molecules in and out of the confined environments of encapsulation complexes or cavitands. The events are reversible and the original states can be recovered by treatment with brief heating, conventional chelating agents, or changes in protonation states, respectively. The control over these spaces augurs well for applications in drug delivery and sensors for small molecules.
Supramolecular Structure of an Unsymmetrical Pyrazine‐Modulated Tetrapyridyltriamide and Its Complexes
Authors: Wang Wen‐Zhen , Ismayilov Rayyat Huseyn , Lee Gene‐Hsiang , Peng Shie‐Ming 
Published: May 2015

AbstractAn unsymmetrical pyrazine‐modulated oligo‐α‐pyridylamine ligand as N2‐(pyrazin‐2‐yl)‐N6‐(6‐(pyridin‐2‐ylamino)pyridin‐2‐yl)pyridine‐2,6‐diamine (H3tpz) and its copper(II) and cobalt(II) complexes have been synthesized and structurally characterized. The free ligand H3tpz (1) exhibits a syn‐anti‐syn‐anti‐syn‐anti conformation, and shows a double chain supramolecular structure through hydrogen bonds and π‐π interactions. H3tpz is a quadridentate ligand in both copper and cobalt mononuclear complexes and coordinates to metal atoms in an all‐anti mode. The copper(II) ion in [Cu(H3tpz)(ClO4)]‐ClO4 (2) is five‐coordinated in tetragonal pyramid geometry with one of the perchlorate anions being weakly coordinated at the apex position. The cobalt(II) ion in [Co(H3tpz)(CH3OH)2](ClO4)2 (3) is six‐co‐ordinated in octahedron geometry. Extensive hydrogen bonds are formed, and construct the complexes 2 and 3 into 1D supramolecular structure.
Advances in Use of p‐H2 as a Novel Host for Matrix IR Spectroscopy
Authors: Bahou Mohammed , Huang Chiung‐Wei , Huang Ya‐Ling , Glatthaar Joerg , Lee Yuan‐Pern 
Published: May 2015

AbstractA review of recent advances in IR spectroscopy using p‐H2 as a matrix host in our laboratory is presented. The softness of this novel p‐H2 matrix host not only makes high‐resolution spectroscopy feasible but also provides new applications. Molecular motion, such as the rotation of C2H4, internal rotation (torsion) of CH3OH, and rotation of CH3F about a single axis are characterized in this p‐H2 matrix. In contrast, no evidence for rotation of CH3I and CH3 was found. The diminution of the cage effect leads to the possibility of production of free radicals via either photolysis in situ or bimolecular reactions of molecules with atoms that are produced in situ from their molecular precursors. Taking advantage of these unique features, we identified the IR spectrum of CH3 produced from photolysis of CH3I and CH3S produced from photolysis of CH3SCH3 and CH3SSCH3. The reaction of Cl with CS2 in solid p‐H2 yields ClSCS instead of ClCS2. The reaction of Cl with HCOOH in solid p‐H2 yields only a complex, Cl·HCOOH, not HCl and HOCO. The presence of o‐H2 in trace proportions turned out to be an important factor in the interpretation of IR spectra of species embedded in solid p‐H2. Experimental techniques to minimize the amount of o‐H2 and to characterize its relative concentration with spectra of H2O·o‐H2 are discussed.
Preparation and Characterization of Ni or Co/Cu Multilayer Nanowires
Authors: Liu Ru‐Shi , Chang Sung‐Chun , Chen Po Yuan , Hu Shu‐Fen , Huang Chao Yuan 
Published: May 2015

AbstractHighly ordered nanowires with multilayer structure of Ni/Cu, have been successfully prepared by pulsed chemical electrodeposition into nanoporous templates and the diameter (35 and 200 nm) of wires can be easily controlled by pore size of template. The nanowires have been characterized by transmission electron microscopy (TEM), magnetic force microscopy (MFM), and vibrating sample magnetometer (VSM) and high magnetic perpendicular anisotropy can be achieved by modulating the shape of nanowires. It was found that the coercivity (Hc) and squarness (S: Mr/Ms) of the nanowires are strongly dependent on the diameter and aspect ratio as well as on dipolar coupling between the ferromagnetic segments and the nanowires (aspect ratio: 11.4) can be obtained high perpendicular magnetic anisotropy with Hc: 895 Oe and S: 0.77 of Ni/Cu nanowires. The magnetoresistance ratios along the parallel and perpendicular axes of nanowires are 23.4% and 7.2% respectively. Owing to its high bit density, the structure may be suitable for ultrahigh‐density magnetic recording media.
Carbonylchromium Chalcogenide Complexes: Synthesis, Reactivity and Properties
Authors: Shieh Ming‐Huey , Miu Chia‐Yeh 
Published: May 2015

AbstractRecently, we have developed several synthetic routes to a series of chalcogen‐containing group 6 (emphasizing on chromium) carbonyl clusters, in which the interesting structural transformations, reactivity, and properties of the resultant clusters have also been investigated. This review will focus on the aspects of the research carried out in our laboratory. In this account, the practical synthetic methodologies and metal‐metal exchange and cluster expansion reactions together with structural features of these Cr‐containing complexes are systematically described and compared.
Electrophilic Aromatic Nitration: Substituent Effects of Monosubstituted Benzenes
Authors: Wang Peng‐Cheng , Chen Jing , Lu Ming 
Published: May 2015

AbstractBy the method of Density Functional Theory, at B3LYP/6–311G** level, works are done to optimize the charge distribution of nine kinds of aromatic groups. Meanwhile, the activation hardness is introduced and used to check the presented calculations' validity. Based on these studies, the orientation of electrophilic aromatic substitution is discussed. Experimental results show that the nitrification activity described with NBO net charge has a relationship with the nitrification strength, and it is an excellent index for predicting orientation effects.
Silica‐Bonded N‐Propyl Sulfamic Acid: A Recyclable Catalyst for the Synthesis of 1,8‐Dioxo‐decahydroacridines, 1,8‐Dioxo‐octahydroxanthenes and Quinoxalines
Authors: Rashedian Fatemeh , Saberi Dariush , Niknam Khodabakhsh 
Published: May 2015

AbstractSilica bonded N‐propyl sulfamic acid (SBNPSA) is employed as a solid acid catalyst for the synthesis of 1,8‐dioxo‐decahydroacridines and 1,8‐dioxo‐octahydroxanthenes in high yields and short reaction times in ethanol under reflux conditions. Also, this solid acid catalyzed the reaction of 1,2‐diamino compounds with 1,2‐dicarbonyl compounds for the synthesis of quinoxaline derivatives at room temperature. The catalyst could be recycled and reused several times without any loss of efficiency.
Development of New Kinetic‐Spectrophotometric Method for Determination Insecticide Dimethoate in Milk and Water
Authors: Grahovac Zora M. , Mitić Snež Ana S. , Pecev Emilija T. , Pavlović Aleksandra N. 
Published: May 2015

AbstractIn the present study, a new sensitive and simple kinetic‐spectrophotometric method for the determination of the insecticide dimethoate[O,O‐dimethyl‐S‐(N‐methyl‐carbomoylmethyl)‐phosphoro‐dithioate] is developed. The method is based on the inhibited effect of dimethoate on the oxidation of sulphanilic acid (SA) by potassium periodate in acetate buffer in presence Fe(III) ion and 1,10‐phenantroline. Dimethoate was determined with linear calibration graph in the interval from 28.10 to 196.70 ng/mL. The optimized conditions yielded a theoretical detection limit of 21.64 ng/mL based on the 3Sb criterion. The RSD is 4.85‐1.2% for the concentration interval of dimethoate 28.10‐196.70 ng/mL. The reaction was followed spectrophotometrically at 368 nm. The kinetic parameters of the reaction are reported, and the rate equations are suggested. The developed procedure was successfully applied to the rapid determination of dimethoate in spiked milk and water samples. Liquid‐liquid extraction and solid‐phase extraction (SPE) was used for extraction of dimethoate from milk and water samples with Chromabond® (Macherey‐Nagel) C18 cartridges. The HPLC method was used like an comparative method to verify the results. The results obtained by two different methods showed good agreement.
Preconcentration and Determination of Trace Amount of Nickel in Water and Biological Samples by Dispersive Liquid‐Liquid Microextraction
Authors: Shirkhanloo Hamid , Rouhollahi Ahmad , Mousavi Hassan Zavvar 
Published: May 2015

AbstractA new, simple and highly sensitive dispersive liquid‐liquid microextraction method using a ionic liquid, i.e., 1‐Butyl‐3‐methylimidazolium hexafluorophosphate ([C4MIM][PF6]) for nickel determination at trace levels in real samples was developed. Nickel was chelated with diethyl dithiocarbamat reagent and extracted into an ionic liquid. Ni was back‐extracted from the IL phase with 200 μL of 0.5 mol L−1 nitric acid and determined by electrothermal atomic absorption spectrometry (ETAAS). Various parameters such as pH, amount of ionic liquid, eluent type and volume, chelating agent concentration, volume of the sample solution and matrix interference effect on the recovery of the metal ions have been studied. Under the optimum conditions, the enrichment factor 100 was obtained from only 20 mL of sample. The calibration graph was linear in the rage of 20‐700 ng L−1 of nickel with detection limit of 5 ng L−1. The relative standard deviation (R.S.D.s) for eight replicate measurements of 20 ng L−1 of nickel was 5.6%. Validation of the methodology was performed by standard addition method and analysis of certified reference material. The method was successfully applied to the determination of Ni+2 in serum and tap water samples.
Doubly β‐Functionalized Zinc(II) Porphyrin‐sensitized TiO2 Solar Cells
Authors: Park Sun Woo , Hwang Dae Sub , Kim Dong Young , Kim Dongho 
Published: May 2015

AbstractFunctionalized porphyrin at β‐positions with carboxylic acid groups was prepared to investigate the photovoltaic function as dye‐sensitized nanocrystalline‐TiO2 solar cells. The electronic structures of the porphyrin macrocyclic core are strongly coupled with olefinic side chains so that the absorption spectrum exhibits broad and red‐shifted Soret and Q‐bands. 2b‐Zn, which is a metallated porphyrin with 2‐propenoic acid groups at two β‐positions, exhibits the power conversion efficiency of 5.18%. From such photovoltaic performance, we can suggest that multiple pathways through olefinic side chains at two β‐positions enhance the electron injection efficiency. For improvement of the solar cell efficiency, we have employed empirical surface modification which is a post‐treatment of the TiO2 film by aqueous TiCl4. As a result, post‐TiCl4 treated cell exhibits the power conversion efficiency of 5.37% and the maximum incident photon to current efficiency of 67.2% in the Soret band region.
A New Microstructured DSC Photoelectrode for Potential High Power Conversion Efficiency
Authors: Zhang Qi‐Feng , Park Kwangsuk , Cao Guo‐Zhong 
Published: May 2015

AbstractThis paper includes an overview of general approaches and efforts to enhance the power conversion efficiency in dye‐sensitized solar cells (DSC) and then the recent development of hierarchically structured photoelectrodes for DSC. Hierarchically structured photoelectrodes are made of submicron‐sized aggregates of ZnO nanocrystallites. Such structured photoelectrodes retain the desired large surface area and crystal facets for dye molecule adsorption and possess the ability to scatter the visible light within the photoelectrodes, so as to enhance light adsorption and thus lead to more efficient photon capturing. In ZnO DSC, hierarchically structured photoelectrodes demonstrated over 200% enhancement in power conversion efficiency.
Porphyrin‐Perylene Dyes for Dye‐Sensitized Solar Cells
Authors: Chen Hong‐Yi , Lee Cheng‐Wei , Chuang Shu‐Han , Lu Hsueh‐Pei , Diau Eric Wei‐Guang , Yeh Chen‐Yu 
Published: May 2015

AbstractTwo novel porphyrin‐perylene dyads 1 and 2 for DSSC applications have been synthesized. The absorption band of the perylene fills up the trough between the Soret and Q bands of the porphyrin, leading to an increase in the absorption efficiency of the dye. The highly conjugated acetylenic bridge mediates strong electronic coupling between the porphyrin and perylene units and results in the extension of π‐conjugation of the porphyrin ring. The Soret and Q bands are broadened and red‐shifted and the light‐harvesting effect is thus improved. We propose that energy transfer occurs from the photoexcited perylene to porphyrin for dyad 1 whereas energy transfer proceeds from the excited porphyrin to perylene for dyad 2. Our studies show that multichromophoric dyes used for DSSC can be designed in a rational manner with predictable photophysical behavior and efficient light‐harvesting properties, but the efficiency of the energy transfer process in a consecutive model needs to be controlled for a significant improvement of the cell performance using perylene‐porphyrin sensitizers.
Characteristics of Zinc Oxide Crystallites Deposited on ITO for Dye‐Sensitized Solar Cells
Authors: Huang Chueh‐Jung , Chao Wen‐Kai , Shieu Fuh‐Sheng 
Published: May 2015

AbstractZnO large crystallites on ITO glass were prepared by acid sol technology. The characteristic and microstructure of the ZnO crystallites on the ITO glass were investigated. Moreover, the ZnO/ITO glass were used as photoelectrodes to fabricate the dye sensitized solar cells (DSSCs), and the effects of the ZnO crystallites on the photoconversion efficiencies of the DSSCs were also investigated. The results of XRD, FE‐SEM, TEM and UV‐visible spectroscopy analyses indicate that the deposited ZnO crystallites exhibit a hexagonal wurtizite structure with particle size over than 200 nm, and lead the ZnO/ITO electrode to induce a red‐shift toward longer wavelength. The solar energy conversion efficiency (η%) of the DSSCs in the case of ZnO/ITO cell electrode is higher than that of the ITO cell electrode. The conversion efficiency was found to be 0.92% and 0.48% for the ZnO/ITO and the ITO electrodes, respectively.
The Protection of Flexible DSSC Polymeric Substrate using Atmospheric Pressure Plasma Coating
Authors: Huang Chun , Wu Shin‐Yi , Chang Ya‐Chi , Pan Chien‐Hsuan , Tsai Ching‐Yuan 
Published: May 2015

AbstractProtective SiOx coating on polymeric substrates were deposited at room temperature by atmospheric pressure plasma jet (APPJ), using HMDSO (Hexamethylsiloxane) as monomer and argon (Ar) as carrier gas, have been investigated for the surface properties as a function of plasma operational parameters including in RF plasma power, substrate temperature, and monomer flow rate. The improved hardness of direct APPJ deposited polymeric substrates have been determined by pencil test and related to the chemical composition and to the surface morphology of the plasma coated SiOx layers. The direct APPJ deposited films have been analyzed by Fourier transform infrared spectroscopy (FTIR), UV‐vis spectrometer, and AFM (Atomic Forced Microscopy). From FT‐IR analysis, it resulted that remote APPJ deposited films become more inorganic as the monomer flow rate increased. UV‐vis spectra, detected in the range of 300‐800 nm, examined the improved transparency in the visible and increased absorption in UV region. Protective SiOx coating has a potential application in dye‐sensitized‐solar‐cells.