Vibrational spectroscopy differentiates between multipotent and pluripotent stem cells

Over the last few years, there has been an increased interest in the study of stem cells in biomedicine for therapeutic use and as a source for healing diseased or injured organs/tissues. More recently, vibrational spectroscopy has been applied to study stem cell differentiation. In this study, we have used both synchrotron based FTIR and Raman microspectroscopies to assess possible differences between human pluripotent (embryonic) and multipotent (adult mesenchymal) stem cells, and how O(2) concentration in cell culture could affect the spectral signatures of these cells. Our work shows that infrared spectroscopy of embryonic (pluripotent) and adult mesenchymal (multipotent) stem cells have different spectral signatures based on the amount of lipids in their cytoplasm (confirmed with cytological staining). Furthermore, O(2) concentration in cell culture causes changes in both the FTIR and Raman spectra of embryonic stem cells. These results show that embryonic stem cells might be more sensitive to O(2) concentration when compared to mesenchymal stem cells. While vibrational spectroscopy could therefore be of potential use in identifying different populations of stem cells further work is required to better understand these differences.     

Interpolation of multidimensional diabatic potential energy matrices

A method for constructing diabatic potential energy matrices by interpolation of ab initio quantum chemistry data is described and tested. This approach is applicable to any number of interacting electronic states, and relies on a formalism and a computational procedure that are more general than those presented previously for the case of two electronic states. The method is tested against an analytic model for three interacting electronic states of NH(3) (+).     

Determination of Iprodione,Vinclozolin, and Procymidone as the Heptafluorobutyramides of 3,5-Dichloroaniline

Abstract

A method was developed for the determination of three fungicides in foods based on alkaline degradation to 3,5-dichloroaniline, isolation of the latter by steam distillation and measurement of the heptafluorobutyrate by gas chromatography. Recoveries averaged 91% from several commodities spiked at from 10–80ppb. The minimum detectable limit of 2.6ppb was attainable in grape, with similar limits found in strawberry, tomato and beans. The method was capable of determining degradation products formed as a result of cooking.     

Ion implanted species dependence in silicon oxidation

The effect on thermal oxidation of implantation of the alkali species Li, Na, K, Rb and Cs has been studied. A correlation is found with the atomic and ionic radii and atomic masses of the implanted species, the larger ions leading to greater oxidation. We propose that the implanted species may affect the oxide plasticity and that this may be the controlling factor which determines the degree of oxidation.     

An Improved Procedure for the Synthesis of Prostaglandin Analogues

Hydrozirconation-iodination of a terminal acetylene followed by lithium-iodide exchange and finally dilithio cyanocuprate mediated conjugate addition to an appropriate cyclopentenone is reported as an efficient method for the synthesis of prostaglandin analogues.     

Exploiting Aggregation To Achieve Phase Separation in Macrocyclization

The aggregation properties of poly(ethylene glycol) (PEG) can be exploited in organic synthesis to control dilution effects. Through the use of solvent mixtures containing PEG₄₀₀/MeOH, macrocyclization by Glaser–Hay coupling can be conducted at high concentrations. The origin of the selectivity has been studied by using surface tension measurements, UV spectroscopy, and chemical tagging and demonstrates the dependence of the yield and selectivity on the aggregation of PEG₄₀₀ and its ability to preferentially solubilize organic substrates, resulting in a phase separation from the catalyst system.