β-Sitosterol: Supercritical Carbon Dioxide Extraction from Sea Buckthorn (Hippophae rhamnoides L.) Seeds

Supercritical fluid extraction represents an efficient and environmentally friendly technique for isolation of phytosterols from different plant sources. Sea buckthorn (Hippophae rhamnoides L.) seeds were extracted with supercritical carbon dioxide at pressures ranging from 15–60 MPa and temperatures of 40–80 °C. Oil and β-sitosterol yields were measured in the extraction course and compared with Soxhlet extraction with hexane. The average yield of β-sitosterol was 0.31 mg/g of seeds. The maximum concentration of β-sitosterol in the extract, 0.5% w/w, was achieved at 15 MPa, 40 °C, and a carbon dioxide consumption of 50 g/g of seeds. The extraction rate was maximal at 60 MPa and 40 °C. Both β-sitosterol yield and its concentration in the extract obtained with hexane were lower than with carbon dioxide

Motif grammar: The basis of the language of gene expression

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The pioneer factor OCT4 requires the chromatin remodeller BRG1 to support gene regulatroy element funciton in mouse embryonic stem cells

Pioneer transcription factors recognise and bind their target sequences in inaccessible chromatin to establish new transcriptional networks throughout development and cellular reprogramming. During this process, pioneer factors establish an accessible chromatin state to facilitate additional transcription factor binding, yet it remains unclear how different pioneer factors achieve this. Here, we discover that the pluripotency-associated pioneer factor OCT4 binds chromatin to shape accessibility, transcription factor co-binding, and regulatory element function in mouse embryonic stem cells. Chromatin accessibility at OCT4-bound sites requires the chromatin remodeller BRG1, which is recruited to these sites by OCT4 to support additional transcription factor binding and expression of the pluripotency-associated transcriptome. Furthermore, the requirement for BRG1 in shaping OCT4 binding reflects how these target sites are used during cellular reprogramming and early mouse development. Together this reveals a distinct requirement for a chromatin remodeller in promoting the activity of the pioneer factor OCT4 and regulating the pluripotency network

Supercritical Fluid Extraction of Plant Flavors and Fragrances

Supercritical fluid extraction (SFE) of plant material with solvents like CO2, propane, butane, or ethylene is a topic of growing interest. SFE allows the processing of plant material at low temperatures, hence limiting thermal degradation, and avoids the use of toxic solvents. Although today SFE is mainly used for decaffeination of coffee and tea as well as production of hop extracts on a large scale, there is also a growing interest in this extraction method for other industrial applications operating at different scales. In this review we update the literature data on SFE technology, with particular reference to flavors and fragrance, by comparing traditional extraction techniques of some industrial medicinal and aromatic crops with SFE. Moreover, we describe the biological activity of SFE extracts by describing their insecticidal, acaricidal, antimycotic, antimicrobial, cytotoxic and antioxidant properties. Finally, we discuss the process modelling, mass-transfer mechanisms, kinetics parameters and thermodynamic by giving an overview of SFE potential in the flavors and fragrances arena

Electron-Rich Vaska-Type Complexes trans-[Ir(CO)Cl(2-Ph2PC6H4COOMe)(2)] and trans-[Ir(CO)Cl(2-Ph2PC6H4OMe)(2)]: Synthesis, Characterisation and Reactivity

The in-situ-generated dimeric precursor [Ir(CO)(2)Cl](2) reacts with four molar equivalents of the ligands 2-Ph2PC6H4-COOMe (a) and 2-Ph2PC6H4OMe (b) to afford tetracoordinated complexes of the type trans-[Ir(CO)ClL2] (1a, 1b), where L = a and b. The IR spectra of 1a and 1b in CHCl3 solution show the terminal nu(CO) bands at around 1957 and 1959 cm (1), respectively, which are significantly lower in frequency compared to Vaska's complex, trans-[Ir(CO) Cl-(PPh3)(2)] (1965 cm(-1)) and substantiate the enhanced electron density at the metal centre. The single-crystal X-ray structure of 1a indicates iridium-oxygen (ester group) distances [Ir center dot center dot center dot O(2) 3.24 angstrom Ir center dot center dot center dot O(5) 3.29 angstrom] and angle [O(5)center dot center dot center dot Ir center dot center dot center dot O(2) 157.25 degrees] suggesting a long-range intramolecular "secondary" Ir center dot center dot center dot O interaction resulting in a pseudo-hexacoordinated complex. Complex 1b reacts with O-2 to generate [Ir(O-2)(CO)-Cl(2-Ph2PC6H4OMe)(2)] (2b), while 1a remains unreactive. Complex 2b shows a distorted octahedral structure with peroxo O-O linkage (O2-O3 1.47 angstrom). The kinetic study of the reaction of 1b and Vaska's complex towards dioxygen addition reveals that the rate of dioxygen addition to 1b is about three times faster than Vaska's complex. Complexes 1a and 1b undergo oxidative addition with small molecules like CH3I and I-2 to produce Ir-III carbonyl species of the type [Ir(CO)Cl(CH3)IL2] (3a, 3b) and [Ir(CO)ClI2L2] (4a, 4b), where L = a, b.</p