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191.
Sana Jahanshahi‐Anbuhi Kevin Pennings Vincent Leung Dr. Meng Liu Carmen Carrasquilla Dr. Balamurali Kannan Prof. Dr. Yingfu Li Prof. Dr. Robert Pelton Prof. Dr. John D. Brennan Prof. Dr. Carlos D. M. Filipe 《Angewandte Chemie (International ed. in English)》2014,53(24):6155-6158
A simple and inexpensive method is reported for the long‐term stabilization of enzymes and other unstable reagents in premeasured quantities in water‐soluble tablets (cast, not compressed) made with pullulan, a nonionic polysaccharide that forms an oxygen impermeable solid upon drying. The pullulan tablets dissolve in aqueous solutions in seconds, thereby facilitating the easy execution of bioassays at remote sites with no need for special reagent handling and liquid pipetting. This approach is modular in nature, thus allowing the creation of individual tablets for enzymes and their substrates. Proof‐of‐principle demonstrations include a Taq polymerase tablet for DNA amplification through PCR and a pesticide assay kit consisting of separate tablets for acetylcholinesterase and its chromogenic substrate, indoxyl acetate, both of which are highly unstable. The encapsulated reagents remain stable at room temperature for months, thus enabling the room‐temperature shipping and storage of bioassay components. 相似文献
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Ana C. Q. Silva Armando J. D. Silvestre Carla Vilela Carmen S. R. Freire 《Molecules (Basel, Switzerland)》2022,27(1)
Natural polymers have emerged as promising candidates for the sustainable development of materials in areas ranging from food packaging and biomedicine to energy storage and electronics. In tandem, there is a growing interest in the design of advanced materials devised from naturally abundant and renewable feedstocks, in alignment with the principles of Green Chemistry and the 2030 Agenda for Sustainable Development. This review aims to highlight some examples of the research efforts conducted at the Research Team BioPol4fun, Innovation in BioPolymer-based Functional Materials and Bioactive Compounds, from the Portuguese Associate Laboratory CICECO–Aveiro Institute of Materials at the University of Aveiro, regarding the exploitation of natural polymers (and derivatives thereof) for the development of distinct sustainable biobased materials. In particular, focus will be given to the use of polysaccharides (cellulose, chitosan, pullulan, hyaluronic acid, fucoidan, alginate, and agar) and proteins (lysozyme and gelatin) for the assembly of composites, coatings, films, membranes, patches, nanosystems, and microneedles using environmentally friendly strategies, and to address their main domains of application. 相似文献
196.
Jos-Luis Milln Gerardo Martínez Carmen Mijangos Jos Manuel Gmez-Elvira 《Macromolecular Symposia》1989,29(1):185-196
In the light of some earlier works on nucleophilic substitution on poly(vinyl chloride) (PVC) in solution, a conformational mechanism is proposed. It considers the TT isotactic diad conformation to be the only reactive species and the reaction to be controlled by the conformational equilibria that make such conformation available. As a result all the isotactic and the heterotactic triads are capable of reacting provided that they adopt the GTTG− and the GTTT conformation, respectively. Since the replacement of a definite fraction of isotactic triads, which are assumed to be of the GTTG− conformation, results in an enhanced thermal and photochemical stability, the lability of some chlorines at such triads is proved. Further arguments in favour of the conformational mechanism are afforded through recent results of i) substitution studies in the melt and in aqueous suspension with phase transfer catalysts, ii) accurate 13C NMR measurements of triad variation with degree of substitution. 相似文献
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A conversion - temperature - transformation (CTT) diagram was used to analyze several non-isothermal processes of polymer network formation: a) range of heating rates where reliable kinetic information can be obtained; b) a novel process involving part of the cure in the glassy state; c) phase separation in rubber-modified epoxies cured in heated molds. 相似文献
199.
Pérez-Sirvent C Martínez-Sánchez MJ García-Lorenzo M López-García I Hernández-Córdoba M 《Analytical and bioanalytical chemistry》2007,388(2):495-498
Use of small membrane pumps, instead of peristaltic pumps, to introduce sample and reagent solutions into the spectrometer
has several advantages in atomic fluorescence spectrometric determination of mercury. This simple modification results in
a substantial saving in the time required for the measurements and so 90% of reagent solution volumes and 95% of sample solution
volumes are saved, with a consequent decrease in the volume of waste generated. The sampling frequency is almost tripled,
with no deterioration in sensitivity, which is similar to that obtained by use of peristaltic pumps. The relative standard
deviation for ten consecutive measurements of a 1 μg L−1 mercury solution was approximately 2%.
Figure Small membrane pumps for the atomic fluorescene spectro metric determination of mercury 相似文献
200.
Mirela-Fernanda Zaltariov Angelica VladMaria Cazacu Sergiu ShovaMihaela Balan Carmen Racles 《Tetrahedron》2014
The new dicarboxylic acid, 1,3-bis(p-carboxyphenylene-ester-methylene)tetramethyldisiloxane (H2L, 1) was obtained by treating 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane with a mixture of terephthalic acid and terephthalic acid sodium salt in a 1:1 ratio. In this approach, besides the desired compound 1 (33 wt % yield), the condensation cyclic dimer 2 (7 wt % yield) and an oligomer 3 (10 wt % yield) resulted. The reaction between dicarboxylic acid H2L, where L is the carboxylate ligand, along with imidazole as co-ligand, and copper hydroxide resulted in the formation of a coordination compound [Cu(HIm)4(H2O)2]L·4.5H2O (4). Single-crystal X-ray crystallography has revealed that the crystal structure of 4 is a self-assembled H-bonded three-dimensional supramolecular structure. FTIR and NMR spectral techniques were also used to characterize the formed structures. Optical and thermal properties of all compounds were studied. The stability of the supramolecular structure in solution (methanol) and with temperature was studied using ATR-FTIR. The ability of the macrocycle 2 to bind potassium cations in solution was investigated by UV–vis spectrophotometry. 相似文献