Studies on metal — protein interactions: Inter-comparison among various approaches

Binding ability of mercury, thallium, lead and bismuth with Erythrina variegata seed protein have been investigated using tracer packet technique. Due to the lack of standard methods, inter-comparisons have been made among three different approaches, like trichloroacetic acid (TCA) precipitation, isoelectric precipitation and dialysis of protein after incubation with the metals. Good agreement was observed for all the cases except that of lead.     

Binding constant measurement by hyper-Rayleigh scattering: bilirubin-human serum albumin binding as a case study

In this paper, a new application of the hyper-Rayleigh scattering technique in determining multiple binding constants of a small molecule like bilirubin to a macromolecule like the protein human serum albumin has been demonstrated. Human serum albumin has two binding sites for bilirubin, and the binding constants have been measured by carrying out a second harmonic titration of the protein against bilirubin and vice versa. The measured binding constants K(1) = 1.5 +/- 0.43 x 10(7) M(-1) and K(2) = 1.01 +/- 0.16 x 10(6) M(-1) agree well with the reported values obtained by other methods.     

Cellulose as recyclable organocatalyst for ipso-hydroxylation of arylboronic acids

Cellulose catalyzed oxidative hydroxylation of aryl and hetero-arylboronic acids to the corresponding phenols under metal and base free strategy has been demonstrated. The sustainable ipso-hydroxylation takes place using hydrogen peroxide as an oxidant in water under mild condition in shorter period of time. Interestingly, easy recovery and reusability of heterogeneous catalyst without significant loss in catalytic yield makes the protocol environmentally benign.     

One-pot synthesis of strong solid state emitting mono-cyclometalated iridium(III) complexes: study of their aggregation induced enhanced phosphorescence

Strong solid-state greenish-blue emitting, mono-cyclometalated iridium complexes, [Ir(ppy)(PPh(3))(2)(H)(Cl)], 2a and [Ir(F(2)ppy)(PPh(3))(2)(H)(Cl)], 2b [ppyH = 2-phenylpyridine; F(2)ppyH = 2-(2',4'-difluoro)phenylpyridine], have been synthesized by a convenient route. The 'aggregation induced enhanced phosphorescence (AIEP)' activity exhibited by these complexes has been rationalized.     

Spray reagents for the detection of amino-acids on thin-layer plates

Three spray reagents for the detection of amino-acids on silica-gel thin-layer chromatography plates are reported. The reagents produce various colours, which may be used to identify some of the amino-acids directly, and assist in their detection.     

Gibbs Sampling with Diffuse Proper Priors: A Valid Approach to Data-Driven Inference?

Abstract

This article demonstrates by example that the use of the Gibbs sampler with diffuse proper priors can lead to inaccurate posterior estimates. Our results show that such inaccuracies are not merely limited to small sample settings.     

Fall colouring of bipartite graphs and cartesian products of graphs

The question of whether a graph can be partitioned into k independent dominating sets, which is the same as having a fallk-colouring, is considered. For k=3, it is shown that a graph G can be partitioned into three independent dominating sets if and only if the cartesian product G□K₂ can be partitioned into three independent dominating sets. The graph K₂ can be replaced by any graph H such that there is a mapping f:Q_n→H, where f is a type-II graph homomorphism.The cartesian product of two trees is considered, as well as the complexity of partitioning a bipartite graph into three independent dominating sets, which is shown to be NP-complete. For other values of k, iterated cartesian products are considered, leading to a result that shows for what values of k the hypercubes can be partitioned into k independent dominating sets.     

Accumulation of radiocesium by <Emphasis Type="Italic">Pleurotus citrinopileatus</Emphasis> species of edible mushroom

Pleurotus citrinopileatus, a species of edible mushrooms, is widely accepted food component, especially in Indian subcontinent. The accumulating susceptibility of this edible mushroom species towards long-lived radioisotopes of cesium was studied in controlled laboratory condition using the ¹³⁴Cs (T _1/2 = 2.06 y) radioisotope. It was observed that the experimental mushroom species accumulated ¹³⁴Cs and maximum accumulation took place in the cap portion. The pileus (cap)/stipes (stem) ratio of each ¹³⁴Cs accumulated mushroom sample was determined and found 2.22±0.74. The protein and fat fractions of the experimental mushroom species were extracted separately after accumulation of radiocesium and it was found that most of the radiocesium accumulation occurred in the protein fraction of the mushroom. The mushroom Pleurotus citrinopileatus which is white in color, turned completely black after radiocesium accumulation. The black mushroom so obtained was produced upto fourth generation by tissue culture method without using any radiocesium further. All the successors were found to be black indicating a permanent mutation of the mushroom species.     

Surfactant-promoted enhancement in bioremediation of hexavalent chromium to trivalent chromium by naturally occurring wall algae

Research on Chemical Intermediates - The discharge of hexavalent chromium [Cr(VI)] has resulted in significant pollution because of the presence of Cr(VI) oxyanions. They are highly water-soluble,...     

Renner-Teller and Fermi resonance interactions for the v3=1 and v7=2 vibronic levels in the A2Πu and X2Πg electronic states of HC4H+

The excitation of the v(3) = 1 (σ(g)(+) C-C stretch) and the v(7) = 2 (π(g)(2) C≡C-C bend) modes in the A(2)Π(u) electronic state of diacetylene cations results in Renner-Teller (R-T) and Fermi interactions. The 3(0)(1) and 7(0)(2) vibronic bands in the A(2)Π(u)-X(2)Π(g) transition of HC(4)H(+) have been measured with rotational resolution using cavity ringdown spectroscopy in a supersonic slit jet discharge. The analysis yields T(00) = 20520.828(4) cm(-1), B' = 0.14047(2) cm(-1), and A' = -17.95(1) cm(-1) for the v(3) = 1 and T(00) = 20573.659(4) cm(-1), B' = 0.14018(3) cm(-1), and A' = -11.55(1) cm(-1) for the v(7) = 2 level in the A(2)Π(u) electronic state. A vibronic analysis has been carried out taking into consideration the R-T, spin-orbit, and Fermi resonance interactions between the ν(3) and ν(7) modes. The levels are fitted to the eigenvalues of an appropriate Hamiltonian matrix. This yields the vibrational frequencies ω(3)′ = 811.8 cm(-1) and ω(7)′ = 403.2 cm(-1), Renner parameter ε(7)′ = 0.065, Fermi coefficients W(1)′ = 10.3 cm(-1) and W(2)′ = 5.1 cm(-1), and spin-orbit interaction constant A(SO)′ = -31.1 cm(-1). A corresponding R-T analysis has been carried out for the X(2)Π(g) ground state of HC(4)H(+) using data available in the literature [Callomon, J. H. Can. J. Phys. 1956, 34, 1046]. This gives ω(3)" = 956.2 cm(-1), ω(7)" = 435.4 cm(-1), ε(7)" = 0.028, W(1)" = 7.2 cm(-1), W(2)" = 10.9 cm(-1), and A(SO)" = -33.3 cm(-1).