1,723,081 research outputs found
Synthesis of ethyl laurate by hydrogel immobilized lipase of Bacillus coagulans MTCC-6375
No full textAn alkaline thermo-tolerant lipase from Bacillus coagulans MTCC-6375 was purified and efficiently immobilized onto a synthetic hydrophobic poly (MAc-co-DMA-cl-MBAm)-hydrogel at pH 8.5 and temperature 55°C in 16 h. The hydrogel bound matrix possessed 7.6 IU g -1 matrix lipase activity with a specific activity of 18 IU mg -1 protein. Immobilized lipase was used to catalyze the esterification of lauric acid and ethanol to produce ethyl laurate in n-nonane. The reaction conditions that were optimized to produce ethyl laurate in n-nonane included enzyme/substrate (E/S) ratio, substrate concentration, reaction time and reaction temperature. The optimized parameters were E/S ratio of 0.5 mg mM -1, ethanol:lauric acid in ratio of 100 mM:100 mM and reaction time of 15 h at 65°C under continuous shaking (200 rpm). Optimized conditions resulted in 66% conversion of reactants into ethyl laurate in n-nonane in the presence of 300 mg molecular sieve mL -1 reaction mixture
GABA<sub>A</sub> receptor modulation by the novel intravenous general anaesthetic E-6375
No full textE-6375 (4-butoxy-2-[4-(2-cyanobenzoyl)-1-piperazinyl] pyrimidine hydrochloride) is a new intravenous general anaesthetic with an anaesthetic potency, in mice, comparable to propofol, or etomidate. Here, we examined the effect of E-6375 upon the GABAA receptor, a putative target of intravenous anaesthetic action. E-6375 reversibly enhanced GABA-evoked currents mediated by recombinant GABAA (α1β 2γ2L) receptors expressed in Xenopus laevis oocytes, with little effect on NMDA- and kainate-evoked currents mediated by NR1a/NR2A and GluR1o/GluR2o glutamate receptors, respectively. E-6375 prolonged the decay of GABA-evoked miniature inhibitory postsynaptic currents recorded from rat Purkinje neurones demonstrating the anaesthetic also enhanced the activity of synaptic GABAA receptors. The GABA enhancing action of E-6375 on recombinant GABAA receptors was unaffected by the subtype of the α isoform (i.e. αxβ2γ 2L; x=1-3) within the receptor, but was increased by the omission of the γ2L subunit. Receptors incorporating β2, or β3, subunits were more sensitive to modulation by E-6375 than those containing the β1 subunit. The selectivity of E-6375 was largely governed by the identity (serine or asparagine) of a single amino acid residue within the second transmembrane domain of the β-subunit. The various in vivo actions of general anaesthetics may be mediated by GABA A receptor isoforms that have a differential distribution within the CNS. The identification of agents, such as E-6375, that discriminate between GABAA receptor subtypes may augur the development of general anaesthetics with an improved therapeutic profile.</p
Synthesis of ethyl oleate employing synthetic hydrogel-immobilized lipase of Bacillus coagulans MTCC-6375
No full textTen polymeric hydrogels were chemically synthesized by varying the concentrations of copolymer (DMA) and cross-linker (MBAm) molecules. An alkaline lipase of Bacillus coagulans MTCC-6375 was immobilized onto a poly (MAc-co-DMA-cl-MBAm)-hydrogel support at pH 8.5 and temperature 55ºC in 16 h. The bound lipase possessed 7.6 U.g⁻¹ (matrix) lipase activity with a specific activity of 18 U.mg⁻¹ protein. Hydrogel bound-lipase catalyzed esterification of oleic acid and ethanol to synthesize ethyl oleate in n-nonane. Various kinetic parameters were optimized to produce ethyl oleate using immobilized lipase. The optimal parameters were bound enzyme/substrate (E/S) ratio 0.62 mg/mM, ethanol/oleic acid 100 mM:75 mM or 100 mM:100 mM, incubation time 18 h and reaction temperature 55ºC that resulted in approximately 53% conversion of reactants into ethyl oleate in n-nonane. However, addition of a molecular sieve to the reaction mixture promoted the conversion to 58% in 18 h in n-nonane, which was equivalent to 55 mM of ethyl oleate produced.<br
A novel salinity proxy based on Na incorporation into foraminiferal calcite
Full text linkSalinity and temperature determine seawater density, and differences in both thereby control global thermohaline circulation. Whereas numerous proxies have been calibrated and applied to reconstruct temperature, a direct and independent proxy for salinity is still missing. Ideally, a new proxy for salinity should target one of the direct constituents of dissolved salt, such as [Na+] or [Cl−]. This study investigates the impact of salinity on foraminiferal Na/Ca values by laser ablation ICP-MS analyses of specimens of the benthic foraminifer Ammonia tepida cultured at a range of salinities (30.0–38.6). Foraminifera at lower salinities (30.0 and 32.5) added more chambers (10–11) to their test over the course of the culturing experiment than those maintained at higher salinities (36.1, 7–8 chambers, and 38.6, 6–7 chambers), suggesting that growth rates in this species are promoted by lower salinities. The Na/Ca of cultured specimens correlates significantly with seawater salinity (Na/Ca = 0.22S–0.75, R2 = 0.96, p < 0.01) and size. Values for Na/Ca and DNa vary between 5.17 and 9.29 mmol mol−1 and 0.12–0.16 × 10−3, which are similar to values from inorganic precipitation experiments. The significant correlation between test size and Na/Ca results from co-variation with salinity. This implies that foraminiferal Na/Ca could serve as a robust and independent proxy for salinity, enabling salinity reconstructions independent of calcitic δ18O
Correction: Jerković, I., et al. Composition of Sulla (Hedysarum coronarium L.) Honey Solvent Extractives Determined by GC/MS: Norisoprenoids and Other Volatile Organic Compounds. Molecules 2010, 15, 6375-6385
No full textThe authors wish to make the following correction to paper [1], doi:10.3390/molecules15096375, website: http://www.mdpi.com/1420-3049/15/9/6375. The correct name of the second author is: Carlo I. G. Tuberoso
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Hierarchical clustering of breast cancer cell lines and corresponding EVs on the basis of expression of 6375 unique small RNAs.
No full textHierarchical clustering of breast cancer cell lines and corresponding EVs on the basis of expression of 6375 unique small RNAs.</p
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