Separation of cobalt(II) from nickel(II) by solid-phase extraction into Aliquat 336 chloride immobilized in poly(vinyl chloride)

A solid-phase absorbent obtained by the immobilization of Aliquat 336 chloride in poly(vinyl chloride) is reported to extract preferentially Co(II) from its 7 M hydrochloric acid solutions containing Ni(II). Under the experimental conditions there was no extraction of Ni(II) which allowed the complete separation of these two ions. Co(II) was rapidly and quantitatively back-extracted with deionised water. A mechanism for the extraction of Co(II) is proposed based on the formation of the ion-pair A⁺[HCoCl₄]⁻ where A⁺ is the Aliquat 336 cation. Fe(III) and Cd(II), usually present in Co(II) and Ni(II) samples, were also extracted into the solid-phase absorbent though at a slower rate than Co(II) and they did not interfere with the separation of Co(II) from Ni(II). It was also demonstrated that this approach allowed the complete separation of Ni(II) from the other metal ions mentioned above.     

Comparing Outcomes of Voice Therapy: A Benchmarking Study Using the Therapy Outcome Measure

The quality cycle requires clinicians to assess the outcomes of interventions. Benchmarking is an approach that has been advocated to compare current performance across different services to identify commonalities and significant differences. This article gives the results of a study of outcomes in speech and language therapy (SLT) using the therapy outcome measure (TOM) for patients with voice disorder (dysphonia) comparing outcomes of seven separate speech and language therapy services. The study aimed to identify the similarities and differences in outcomes of care provided by different services. Two hundred and forty patients with dysphonia (age range 3-87.5 years, average 51.9 years) were treated. The results indicated that although there was no significant difference in the profile of the severity of symptomology of patients referred to speech and language therapy in different geographical areas, there was a significant difference in the treatment outcomes across the services and in the stated reason for discharge from treatment. Nevertheless, most patients with dysphonia had a good outcome and this was associated with completion of the course of treatment. There were significant differences in the number of treatment contacts provided by the different services and in the duration (between admission and discharge) of treatment across the services. Benchmarking can provide useful information through use of routinely collected clinical data.     

Response Surface Methodology to Optimize the Isolation of Dominant Volatile Compounds from Monofloral Greek Thyme Honey Using SPME-GC-MS

This study aimed at an experimental design of response surface methodology (RSM) in the optimization of the dominant volatile fraction of Greek thyme honey using solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). For this purpose, a multiple response optimization was employed using desirability functions, which demand a search for optimal conditions for a set of responses simultaneously. A test set of eighty thyme honey samples were analyzed under the optimum conditions for validation of the proposed model. The optimized combination of isolation conditions was the temperature (60 °C), equilibration time (15 min), extraction time (30 min), magnetic stirrer speed (700 rpm), sample volume (6 mL), water: honey ratio (1:3 v/w) with total desirability over 0.50. It was found that the magnetic stirrer speed, which has not been evaluated before, had a positive effect, especially in combination with other factors. The above-developed methodology proved to be effective in the optimization of isolation of specific volatile compounds from a difficult matrix, like honey. This study could be a good basis for the development of novel RSM for other monofloral honey samples.     

Advantages of compound‐specific stable isotope measurements over bulk measurements in studies on plant uptake of intact amino acids

Increasing interest in the ability of plants to take up amino acids has given rise to questions on the accuracy of the commonly used bulk method to measure and calculate amino acid uptake. This method uses bulk measurements of ¹³C and ¹⁵N enrichment in plant tissues after application of dual‐labelled amino acids but some authors have recommended the use of compound‐specific stable isotope (CSI) analysis of the plants' amino acids instead. However, there has never been a direct evaluation of both methods. We conducted a field study applying dual‐labelled (¹³C, ¹⁵N) amino acids (glycine, valine, tyrosine and lysine) to soil of a Plantago lanceolata monoculture. Root and shoot samples were collected 24 h after label application and the isotope composition of the plant tissues was investigated using bulk and CSI measurements. Enrichment of ¹³C in the case of CSI measurements was limited to the applied amino acids, showing that no additional ¹³C had been incorporated into the plants' amino acid pool via the uptake of tracer‐derived C‐fragments. Compared with this rather conservative indicator of amino acid uptake, the ¹³C enrichment of bulk measurements was 8, 5, 1.6 and 6 times higher for fine roots, storage roots, shoot and the whole plant, respectively. These findings show that the additional uptake of tracer‐derived C‐fragments will result in a considerable overestimation of amino acid uptake in the case of bulk measurements. We therefore highly recommend the use of CSI measurements for future amino acid uptake studies due to their higher accuracy. Copyright © 2009 John Wiley & Sons, Ltd.     

Spectroscopic studies of NbCl5 and TaCl5 in methanol solutions. An investigation of the alcoholysis and the formation of organic compounds

Transition Metal Chemistry -     

Investigation of the first and second dehydroxylation of kaolinite

Raw material kaolin Sedlec Imperial and four types of rehydroxylated samples were used to study the processes of the first and second dehydroxylation of kaolinite by thermal analysis and IR spectroscopy. Activation energy (E _a) of these processes was calculated from DSC curves using five isoconversional methods. IR spectroscopy was used to compare structures of the original and rehydroxylated samples. It was proven that the structure of rehydroxylated metakaolinite can closely resemble that of the raw kaolinite under intensive hydrothermal treatment but does not reach the original structure. The E _a values of the second dehydroxylation reach 87–92 % of E _a values of the first dehydroxylation.     

Development of a PDEδ-Targeting PROTACs that Impair Lipid Metabolism

The prenyl-protein chaperone PDEδ modulates the localization of lipidated proteins in the cell, but current knowledge about its biological function is limited. Small-molecule inhibitors that target the PDEδ prenyl-binding site have proven invaluable in the analysis of biological processes mediated by PDEδ, like KRas cellular trafficking. However, allosteric inhibitor release from PDEδ by the Arl2/3 GTPases limits their application. We describe the development of new proteolysis-targeting chimeras (PROTACs) that efficiently and selectively reduce PDEδ levels in cells through induced proteasomal degradation. Application of the PDEδ PROTACs increased sterol regulatory element binding protein (SREBP)-mediated gene expression of enzymes involved in lipid metabolism, which was accompanied by elevated levels of cholesterol precursors. This finding for the first time demonstrates that PDEδ function plays a role in the regulation of enzymes of the mevalonate pathway.     

Absolute configuration and antibiotic activity of neosartorin from the endophytic fungus Aspergillus fumigatiaffinis

Neosartorin (1) was isolated from the endophytic fungus Aspergillus fumigatiaffinis. The absolute configuration of 1, including both axial and central chirality elements, was established as (aR,5S,10R,5′S,6′S,10′R) for the first time on the basis of its electronic circular dichroism (ECD) spectra aided with TDDFT–ECD calculations. Neosartorin (1) exhibited substantial antibacterial activity against a broad spectrum of Gram-positive bacterial species including staphylococci, streptococci, enterococci, and Bacillus subtilis with minimal inhibitory concentrations in the range of 4–32 μg/mL. When the toxicity of 1 against eukaryotic cells was measured using a panel of different cancer cell lines such as HELA and BALB/3T3, the average IC₅₀ values exceeded 32 μg/mL.