PEG Coated Biocompatible Cadmium Chalcogenide Quantum Dots for Targeted Imaging of Cancer Cells

Cancer stands as a leading cause of mortality worldwide and diagnostics of cancer still faces drawbacks. Optical imaging of cancer would allow early diagnosis, evaluation of disease progression and therapy efficiency. To that aim, we have developed highly biocompatible PEG functionalized cadmium chalcogenide based three differently luminescent quantum dots (QDs) (CdS, CdSe and CdTe). Folate targeting scheme was utilized for targeting cancer cell line, MCF-7. We demonstrate the biocompatibility, specificity and efficiency of our nanotool in detection of cancer cells sparing normal cell lines with retained fluorescence of functionalized QDs as parental counterpart. This is the first time report of utilizing three differently fluorescent QDs and we have detailed about the internalization of these materials and time dependent saturation of targeting schemes. We present here the success of utilizing our biocompatible imaging tool for early diagnosis of cancer.     

Theoretical study of keto–enol tautomerism by quantum mechanical calculations (the QM/MC/FEP method)

In this study, the tautomeric equilibrium between the keto and enol forms has been studied for five typical ketones and aldehydes: i‐butanal, acetaldehyde, acetone, acetylacetone, and dimedone. The level of theory used in the gas‐phase calculation was Becke, three‐parameter, Lee–Yang–Parr/6‐311G(d,p)//Becke, three‐parameter, Lee–Yang–Parr/6‐31G(d). The free energies of solvation were included in the calculation by using the free‐energy perturbation method based on Monte Carlo simulation, that is, the quantum mechanical/Monte Carlo/free‐energy perturbation method. Three different models, incorporating no‐water, one‐water, and two‐waters, were adopted. The results showed that in the gas phase the addition of water molecules to the reaction mechanism caused the activation barriers (ΔG^?_gas) to decrease by half relative to the water‐free mechanism, but there was no effect on the relative difference in free energy, ΔG_gas. The solvation effects (ΔG_sol), based on quantum mechanical/Monte Carlo/free‐energy perturbation calculations, were added to those of the gas‐phase results of the one‐water and two‐waters models. The two‐waters model produced values that were very consistent with the experimental data for all of the tautomers. The differences in the relative Gibbs free energy (ΔG_rxn) were less than 1.0 kcal mol^–1. In summary, the inclusion of solvent molecules in gas‐phase calculations plays a very important role in producing results consistent with experimental data. Copyright © 2012 John Wiley & Sons, Ltd.     

Persistence of the bifurcation structure for a semilinear elliptic problem on thin domains

We study a semilinear elliptic problem on thin domains with a bifurcation parameter. It is shown that the set of solutions is upper semicontinuous as the thickness of a domain tends to 0, and that solution branches including bifurcation points persist near those of a one-dimensional limiting equation.     

Stereochemistry of the base-catalyzed methanolysis of 2-phenyl-tetrahydropyrrolo-1,3,2-oxazaphospholes

Diastereomerically pure bicyclic oxazaphospholes were prepared from L-prolinol and phenylphosphonic or thiophosphonic dichloride and their absolute configurations were determined based on the interpretation of NMR spectra. The base-catalyzed methanolysis of those compounds was found to proceed by exclusive PO bond cleavage with complete inversion of configuration.     

木根黄芩中-新黄酮的光谱特征

从木根黄芩(Scutellaria planipes Nakai et Kitag.)中分离得到一新黄酮类化合物. 该化合物被鉴定为5,7,3′,6′-tetrahydroxy-6,8,2′-trimethoxyflavone. 它有很强的抑制5-酯氧合酶活性. 由于该化合物的A环全部被取代，因此，应用一般的光谱技术很难准确归属各碳的化学位移. 我们应用¹³C-¹³C相关谱和酰化位移方法，明确归属了各碳的信号，并订正了文献中对部分信号的错误归属.     

Mizoroki-Heck type arylation of alkenes using aroyl chlorides under base-free conditions

The Mizoroki-Heck type arylation of alkenes with aroyl chlorides accompanied by decarbonylation efficiently proceeds in the presence of a palladium catalyst system, PdCl₂(PhCN)₂/(PhCH₂)Bu₃NCl, even without adding any base. The products can be isolated by a very simple procedure.     

Depinning line of granular YBa2Cu3O7?δ measured with vibrating-reed method

The depinning temperatures in YBa₂Cu₃O_7−δ ceramics and grains have been studied at magnetic field up to 4 T and various amplitudes of vibration. For ceramics sample, large amplitude dependence of depinning temperature T_D was observed, which indicate the decoupling of grains. In the case of a suspension sample (grain), T_D was much lower than that of ceramics.     

Alpha-activation analysis of boron on Si surface and in Si and SiO2 films

Brazil has become the largest producer of biomass ethanol derived from sugar cane. The industrial production is based on the fermentation of sugar cane juice by yeast, inside of large volume vats, in a fed-batch process that recycles yeast cells. To study the dynamics of chemical elements in each operating cycle, five stages of the fementation process were considered: must, yeast suspension, wine, non-yeast wine and yeast cream. For this, a mass balance of the terrigenous elements, Ce, Co, Cs, Eu, Fe, Hf, La, Na, Sc, Sm, and Th, and the sugar cane plant elements, Br, K, Rb, and Zn, were established in fementation vats of an industrial scale unit, with sampling undertaken during different climatic conditions (dry and rainy periods). A similar distribution of the sugar cane characteristics elements was found for the stages analysed, while for the terrigenous elements a trend of accumulation in the yeast cream was observed. Preferential absorption of Br, K, Rb, and Zn by yeast cells was indicated by the smaller concentrations observed in yeast suspension than in yeast cream.