Silver nanoparticles embedded in amine-functionalized silicate sol–gel network assembly for sensing cysteine,adenosine and NADH

Silver nanoparticles embedded in amine-functionalized silicate sol–gel network were synthesized and used for sensing biomolecules such as cysteine, adenosine, and β-nicotinamide adenine dinucleotide (NADH). The sensing of these biomolecules by the assembly of silver nanoparticles was triggered by the optical response of the surface plasmon resonance (SPR) of the silver nanoparticles. The optical sensor exhibited the lowest detection limit (LOD) of 5, 20, and 5 μM for cysteine, adenosine, and NADH, respectively. The sensing of biomolecules in the micromolar range by using the amine-functionalized silicate sol–gel embedded silver nanoparticles was studied in the presence of interference molecules like uridine, glycine, guanine, and guanosine. Thus, the present approach might open up a new avenue for the development of silver nanoparticles-based optical sensor devices for biomolecules.     

Fourier‐transform infrared and Raman spectra,vibrational assignment and density functional theory calculations of 1,4,5‐triazanaphthalene

The Fourier‐transform infrared (FT‐IR) (4000–50 cm⁻¹) and Raman spectra (3500–100 cm⁻¹) of 1,4,5‐triazanaphthalene in polycrystalline state were measured. Comparison between the spectra by two techniques, a series of density functional theory (DFT) calculations and the spectral behaviour upon deuteration were used for the assignment of the vibrational spectra of the title compound. The calculated vibrational wavenumbers by the B3LYP density functionals are generally consistent with the observed spectra. Copyright © 2009 John Wiley & Sons, Ltd.     

Analysis on air suspended particles of Coimbatore — a FTIR study

An infrared absorption method has been used to identify the minerals in dust collected from some parts of Coimbatore, Coimbatore district, Tamil Nadu without grinding. The KBr pellet technique was employed. The results obtained from the IR spectra show the presence of quartz, asbestos, kaolinite, calcite, haematite, montmorllonite, nacrite and coal. The hazardous effect of inhalation of these minerals are explained. The results show Pollachi main road is more contaminated with hazardous minerals.     

Equilibrium diagrams for some AB3 (A=Sb,Bi, As and B=Cl,Br, I) compounds

Summary Equilibrium diagrams for some of the binary V–VII group semiconducting compounds were determined using regular and ideal solution theories. The calculated phase boundaries approximate the experimental curves.

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Riassunto Diagrammi all'equilibrio per qualcuno dei composti semiconduttori del gruppo binario V–VII sono stati determinati usando teorie per soluzioni regolari e ideali. I confini di fase calcolati approssimano le curve sperimentali.

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Резюме Определяются равновесные диаграммы для некоторых бинарных полупроводниковых соединений (V–VII группы), исполъзуя теории регулярных и идеальных растворов. Вычисленные фазовые границы аппроксимируют эксперменталъные кривые.

     

A convenient synthesis of 5-substituted-7-β-D-arabinofuranosylpyrrolo[2,3-d]pyrimidines structurally related to the antibiotics toyocamycin and sangivamycin

4-Amino-7-(2,3,5-tri-O-benzyl-β-D-arabinofuranosyl)pyrrolo[2,3-d]pyrimidine-5-carbonitrile ( 6a ), prepared from 2-ethoxymethyleneamino-5-bromopyrrole-3,4-dicarbonitrile ( 4 ), was debenzylated with boron trichloride to give ara-toyocamycin ( 6b ). Further functional group transformation of 6b provided a route to 4-amino-7-β-D-arabinofuranosylpyrrolo[2,3-d]pyrimidine-5-thiocarboxamide (ara-thiosangivamycin, 7a ), and the corresponding 5-carboxamidoxime 8a and 5-carboxamidine 8b derivatives. Phosphorylation of unprotected 7a with phosphorus oxychloride gave ara-thiosangivamycin 5′-monophosphate ( 7b ). 2′-O-Acetyl-ara-thiosangivamycin ( 10b ) was prepared as a prodrug by acetylation of 9a , followed by deprotection of the t-butyldimethylsilyl groups under acidic conditions without acyl migration.     

A calculation of the compositional conditions to obtain lattice match of III–V semiconductor alloys with InP and GaP substrates

Summary Following the procedure by Moriizumi and Takahashi, we have calculated the compositional conditions to grow epitaxial films of III–V alloys lattice matched to InP and GaP substrates, on the basis of Vegard's law and Pauling's tetrahedral radii. Analytical equations are given and results are also presented in the form of charts with various alloy compositions. The validity of our results has been tested by comparison with the available experimental data.

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Riassunto Seguendo il procedimento di Moriizumi e Takahashi, si sono calcolate le condizioni di composizione per allevare film epitassiali di reticoli con leghe III–V adattate a substrati InP e GaP, sulla base della legge dei raggi tetraedrici di Vegard e Pauling. Si danno equazioni analitiche e si presentano anche risultati nella forma di lamine con varie composizioni di lega. La validità dei nostri risultati è stata controllata mediante confronto con i dati sperimentali disponibili.

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Резюме Следуя процедуре Моридзуми и Такахаши, мы опредляем условия для выращивания зпитаксиальных пленок сплавов −III—−Y, имеющих согласованные решетки с подожками In P и GaP, наоснове закона Вегарда и тетраздральных радиусов Паули. Выводятся аналитические уравнения и приводятся результаты в виде диаграмм с различными составами сплавов. Сравнениес имеющимися зкспериментальными данными подтверЗдает справедливость наших результатов.

     

Effects of polyacrylic acid on the room-temperature phosphorescence of selected compounds

Polyacrylic acid solutions of 4-phenylphenol, p-aminobenzoic acid, 1,2-benzocarbazole, and 5,6-benzoquinoline were spotted on filter paper and the results obtained by room-temperature phosphorescence were compared with similar samples spotted on filter paper without polyacrylic acid. Improvements in sensitivity ranged from 26 times to 1.1 times and limits of detection from 100 times to 1.1 times for the samples on filter paper with polyacrylic acid. The relative standard deviations for the samples with polyacrylic acid added were also improved.     

Existence of random variables with values in the dual of a nuclear space

The aim of this article is to apply some results of L. Schwartz's theory of radonifying maps to prove existence theorems for infinite dimensional valued random variables. As a consequence, we deduce some known results in this direction due to K. Itô, K. Itô and M Nawata, V. Perez-Abreu C., T. Bojdecki and L.G. Gorostiza     

Oxygen sensor via the quenching of room-temperature phosphorescence of perdeuterated phenanthrene adsorbed on Whatman 1PS filter paper

Perdeuterated phenanthrene (d-phen) exhibits strong room-temperature phosphorescence (RTP) when adsorbed on Whatman 1PS filter paper. An oxygen sensor was developed that depends on oxygen quenching of RTP intensity of adsorbed d-phen. The system designed employed a continuous flow of nitrogen or nitrogen-air onto the adsorbed phosphor. The sensor is simple to prepare and needs no elaborate fabrication procedure, but did show a somewhat drifting baseline for successive determinations of oxygen. Nevertheless, very good reproducibility was achieved with the RTP quenching data by measuring the RTP intensities just before and at the end of each oxygen determination. The calibration plots gave a nonlinear relationship over the entire range of oxygen (0-21%). However, a linear range was obtained up to 1.10% oxygen. A detection limit of 0.09% oxygen in dry nitrogen was acquired. Also, carbon dioxide was found to have a minimal effect on the RTP quenching. Thus, oxygen could be measured accurately in relatively large amounts of carbon dioxide. The performance of the oxygen sensor was evaluated by comparing data obtained with a commercial electrochemical trace oxygen analyzer. Also, additional information on the quenching phenomena for this system was obtained from the RTP lifetime data acquired at various oxygen contents.     

Synthesis, growth of organic nonlinear optical crystal: Semicarbazone of 2-amino-5-chloro-benzophenone (S2A5CB) and its characterisation

A new organic crystal of semicarbazone of 2–amino–5–chloro–benzophenone has been grown as a single crystal by slow evaporation solution growth technique for the first time in the literature. The grown crystal has been characterised by proton nuclear magnetic resonance spectral analysis and single crystal and powder X-ray diffraction studies. Functional groups of the crystallised molecules were confirmed by FT-IR and FT-Raman analyses. Mechanical strength of the crystals was studied by microhardness test. Optical transparency of the grown crystals has been studied by UV-Visible spectra. The second harmonic generation property of the compound was analysed.