PEG-SO_3H as catalyst for the Beckmann rearrangement and dehydration of oximes

Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO3H with high yields.     

Methane sensor based on palladium/MWNT nanocomposites

Methane gas sensor was fabricated based on electrocatalytic properties of the Pd/MWNT nanocomposites on indium tin oxide (ITO)glass substrates.A linear response for methane was obtained in the range of 0-16%(v/v)with a detection limit of 0.167%(v/ v)and R.S.D.of 4.1%.After 100 times sensing or stable stored more than 12 months in atmosphere,unconspicuous measurable decrease was observed.The response time was less than 60s at room temperature and ambient pressure.Some common potential interferents in samp...     

Citrinal A,a novel tricyclic derivative of citrinin,from an algicolous fungus Penicillium sp.i-1-1

Citrinal A(1),a novel tricyclic compound with a rare tetrahydro-2H-benzofuro[7-b][1,4]dioxin-9(3H)-one skeleton,along with two known related compounds,citrinin(2) and 2,3,4-trimethyl-5,7-dihydroxy-2,3-dihydrobenzofuran(3) were isolated from an algicolous fungus Penicillium sp.i-1-1.The structure and stereochemistry of 1 were determined by comprehensive spectral and biogenic analysis.Its cytotoxic effects on the A-549 and HL-60 cell lines were evaluated.     

Schisanlactone G,a new 3,4-seco-lanostane triterpenoid from Schisandra sphenanthera

A new 3,4-seco-lanostane triterpenoid,schisanlactone G (1),was isolated from the fruits of Schisandra sphenanthera.Its structure was established on the basis of extensive spectroscopic analysis.2009 Rong Tao Li.Published by Elsevier B.V.on behalf of Chinese Chemical Society.All fights reserved.     

FeCl_3 catalyzed diarylmethanes formations

Under mild condition,using FeCl3 as catalyst,a series of functionalized diarylmethanes were prepared efficiently from the reactions of arenes with paraformaldehyde.This catalytic system is not sensitive to air and moisture.     

Selectively colorimetric detection of cysteine with triangular silver nanoprisms

Triangular silver nanoprisms were prepared and applied to make colorimetric detection of cysteine based on our findings that cysteine could lead to the blue shift of the dipole plasmon resonance absorption,but other 19 kinds of natural amino acids could not.Cysteine with a concentration 160 nmol/L can result in a color change that can be discerned with naked eyes.     

Microsample preparation by dielectrophoresis: isolation of malaria

An important enabling factor for realising integrated micro fluidic analysis instruments for medical diagnostics purposes is front-end sample preparation. Dielectrophoresis is a method that offers great potential for cell discrimination and isolation for sample processing, and here we have applied it to the problem of isolating malaria-infected cells from blood. During development of the malarial pathogen, Plasmodium falciparum, increases occur in the ionic permeability of the plasma membrane of infected erythrocytes. When challenged by suspension in a low conductivity medium, infected cells lose internal ions while uninfected cells retain them. The resultant dielectric differences between infected and uninfected cells were exploited by dielectrophoretic manipulation in spatially inhomogeneous, travelling electrical fields produced by two types of microelectrode arrays. Parasitised cells of ring form or later stage from cultures and clinical specimens were isolated by steric dielectric field-flow-fractionation, focused at the centre of a spiral electrode array, and identified and counted. The dielectrophoretic methods require only a few micro litres of blood, and should be applicable to the production of small, low-cost automated devices for assessing parasite concentrations with potential applicability to drug sensitivity studies and the diagnosis of malaria. By simple adjustment of the electrical field parameters, other cell subpopulations that characterise disease, such as residual cancer cells in blood, can be similarly isolated and analysed.     

Effect of three-body forces on the lattice dynamics of noble metals

A simple method to generate an effective electron-ion interaction pseudopotential from the energy wave number characteristic obtained by first principles calculations has been suggested. This effective potential has been used, in third order perturbation, to study the effect of three-body forces on the lattice dynamics of noble metals. It is found that three-body forces, in these metals, do play an important role. The inclusion of such three-body forces appreciably improves the agreement between the experimental and theoretical phonon dispersion curves.     

An ultra-low hydrolysis sol-gel route for titanosilicate xerogels and their characterization

In this work TiO₂-SiO₂ xerogels were prepared through an ultra low hydrolysis method using titanium and silicon alkoxide. The samples were heat treated to 500°C. The xerogels were characterized using TGA/DTA, FTIR, XRD and TEM. The samples showed the formation of Si–O–Ti bridges by its characteristic vibration within 925–960 cm⁻¹ range. Si–O–Si bond angles were calculated using the central force network model. The TiO₂ in all the samples crystallized on heat treatment to 500°C. The crystallite size calculated using the Scherer formula from the XRD was verified from the Transmission Electron Micrograph. Samples heat treated to 350°C remained amorphous and hence could be used as hosts for biomaterials and organic optical materials.