Search results for "lcsh:Science"
showing 10 items of 2187 documents
Hollandaise sauce and the chemistry behind old and new preparation techniques
2013
Hollandaise sauce has been part of western gastronomy since 1593. Being both an emulsion and a foam, it is a good educational platform for heterophasic systems. Preparing Hollandaise sauce generally includes two phases: forming the foam and forming the emulsion. The sauce is a challenging product and fails easily. Improved preparation techniques have been introduced throughout history. This work combines food historical, scientific and educational perspectives to Hollandaise sauce and introduces an experimental setup to compare the quality of sauces prepared with different techniques.
Low-generation dendrimers with a calixarene core and based on a chiral C2-symmetric pyrrolidine as iminosugar mimics
2012
The preparation of low-generation dendrimers based on a simple calix[4]arene scaffold by insertion of the iminosugar-analogue C2-symmetric 3,4-dihydroxypyrrolidine is described. This methodology allows a rapid incorporation of a considerable number of iminosugar-like moieties in a reduced volume and in a well-defined geometry. The inclusion of alkali-metal ions (sodium and potassium) in the polar cavity defined by the acetamide moieties at the lower rim of the calixarene was demonstrated, which allows also the rigidification of the dendrimer structure and the iminosugar presentation in the clusters. The combination of the supramolecular properties of calixarenes with the advantage of a dend…
Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials
2018
New calixarene-based nanosponges (CaNSs), i.e., hyper-reticulated polymers constituted by calixarene monomer units joined by means of bis(1,2,3-trialzolyl)alkyl linkers, were synthesized, characterized and subjected to preliminary tests to assess their supramolecular absorption abilities towards a set of suitable organic guests, selected as pollutant models. The synthesis was accomplished by means of a CuAAC reaction between a tetrakis(propargyloxy)calix[4]arene and an alkyl diazide. The formation of the polymeric network was assessed by means of FTIR and 13C{1H} CP-MAS solid-state NMR techniques, whereas morphological characterization was provided by SEM microghaphy. The materials were pro…
Polyaminoazide mixtures for the synthesis of pH-responsive calixarene nanosponges
2019
Two mixtures of polyaminoazides were synthesized by a nucleophilic displacement strategy providing no separation of the components. The mixtures were adequately characterized by means of combined HR-ESIMS, FTIR and NMR techniques and, despite their complexity, they were successfully used to accomplish the subsequent preparation of pH-sensitive calixarene hyper-reticulated nanosponge materials. The desired responsivity to pH variations of the nanosponges obtained was verified by means of absorption tests on a set of organic pollutant model molecules.
Information Decomposition in Bivariate Systems: Theory and Application to Cardiorespiratory Dynamics
2015
In the framework of information dynamics, the temporal evolution of coupled systems can be studied by decomposing the predictive information about an assigned target system into amounts quantifying the information stored inside the system and the information transferred to it. While information storage and transfer are computed through the known self-entropy (SE) and transfer entropy (TE), an alternative decomposition evidences the so-called cross entropy (CE) and conditional SE (cSE), quantifying the cross information and internal information of the target system, respectively. This study presents a thorough evaluation of SE, TE, CE and cSE as quantities related to the causal statistical s…
ULTRASOUND-ASSISTED AND ENZYME-ASSISTED EXTRACTION OF FRUCTANS AND PHENOLICS FROM PARSNIP (PASTINACA SATIVA L.)
2019
Parsnip (Pastinaca sativa L.) is a vegetable that gained attention due to its significant content of fructans, besides macronutrients and other biologically active compounds. The major compound of fructan class is inulin, an ingredient with prebiotic properties used in pharmaceutical and functional food industries. The main purpose of this study was to evaluate the extraction yield of fructans and phenolics in fresh and dried parsnip root following non-conventional techniques (ultrasound and enzyme -assisted extraction) and to compare it to that of the traditional method. Extraction was performed in water, as eco-friendly solvent. Ultrasound-assisted extraction was optimized for different e…
Electrosynthesis and electrochemistry
2015
Since the pioneering work of Kolbe, electrochemistry and electrosynthetic methods have been a part of the repertoire of the organic synthesis toolbox [1–2]. In general, only electrons are employed as reagents or the reagents are electrochemically regenerated. Consequently, waste can be avoided, and limited resources can be used in a careful and economic manner. Because alternative reaction pathways are employed by electrosynthetic methods, scarce and toxic elements can be replaced or are not required at all [3]. Moreover, in the foreseeable future regenerative sources of electricity, for example, photovoltaics and wind power, will provide a surplus of electricity as the current unsteady sup…
Building natural science learning through youth science camps
2018
This study focuses on a youth science camp for pupils in sixth to ninth grades that is organized annually by the University of Jyväskylä, Finland. The main idea of the science camp is to learn to do guided inquiry in nature. The study investigates the significance of science camp for encouraging young participants to learn science and how the camp supports their learning. The research method used was a survey. Altogether, 47 youth participated in the camp in 2012 and 2013. The results show that the participants wanted to learn more about science than secondary school could offer, and science camp had a positive impact on their interest in science. It was possible to introduce important conc…
SF002-96-1, a new drimane sesquiterpene lactone from an Aspergillus species, inhibits survivin expression
2013
Survivin, a member of the IAP (inhibitor of apoptosis) gene family, is overexpressed in virtually all human cancers and is functionally involved in the inhibition of apoptosis, regulation of cell proliferation, metastasis and resistance to therapy. Because of its upregulation in malignancy, survivin has currently attracting considerable interest as a new target for anticancer therapy. In a screening of approximately 200 strains of imperfect fungi for the production of inhibitors of survivin promoter activity, a new drimane sesquiterpene lactone, SF002-96-1, was isolated from fermentations of an Aspergillus species. The compound inhibited survivin promoter activity in transiently transfected…
Clicked and long spaced galactosyl- and lactosylcalix[4]arenes: New multivalent galectin-3 ligands
2014
Four novel calix[4]arene-based glycoclusters were synthesized by conjugating the saccharide units to the macrocyclic scaffold using the CuAAC reaction and using long and hydrophilic ethylene glycol spacers. Initially, two galactosylcalix[4]arenes were prepared starting from saccharide units and calixarene cores which differ in the relative dispositions of the alkyne and azido groups. Once the most convenient synthetic pathway was selected, two further lactosylcalix[4]arenes were obtained, one in the cone, the other one in the 1,3-alternate structure. Preliminary studies of the interactions of these novel glycocalixarenes with galectin-3 were carried out by using a lectin-functionalized chip…