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991.
Polymer based interfaces as bioinspired 'smart skins' 总被引:1,自引:0,他引:1
This work reports on already achieved results and ongoing research on the development of complex interfaces between humans and external environment, based on organic synthetic materials and used as smart 'artificial skins'. They are conceived as wearable and flexible systems with multifunctional characteristics. Their features are designed to mimic or augment a broad-spectrum of properties shown by biological skins of humans and/or animals. The discussion is here limited to those properties whose mimicry/augmentation is achievable with currently available technologies based on polymers and oligomers. Such properties include tactile sensing, thermal sensing/regulation, environmental energy harvesting, chromatic mimetism, ultra-violet protection, adhesion and surface mediation of mobility. Accordingly, bioinspired devices and structures, proposed as suitable functional analogous of natural architectures, are analysed. They consist of organic piezoelectric sensors, thermoelectric and pyroelectric sensors and generators, photoelectric generators, thermal and ultra-violet protection systems, electro-, photo- and thermo-chromic devices, as well as structures for improved adhesion and reduced fluid-dynamic friction. 相似文献
992.
Reversed-phase capillary electrochromatography in a 5-microm C18 fully packed capillary was employed to optimize the separation of negatively charged nonsteroidal anti-inflammatory drugs. The effect of the physico-chemical parameters and different analysis modes on the separation of 2-arylpropionic acids was studied and evaluated. The mobile phase composition, buffer type, concentration and pH differently influenced the peak efficiency and resolution, selectively modulating the analytes interaction with the stationary phase. The use of zwitterionic MES or acetate mobile phases strongly modulated the analytes migration order and peak efficiency. The optimum experimental conditions were found in MES buffer, pH 5.0, containing the 75% acetonitrile-methanol (1:1). All the analytes were baseline separated in a mixture in less than 13 min with peak efficiencies in the range of 78,500-84,200 N/m. Under these conditions the analytes were negatively charged and their effective electrophoretic mobilities played a role in the separation. The analysis of different pharmaceutical preparations containing anti-inflammatory drugs, e.g. drops and tablets, is also presented after a very simple sample pretreatment. 相似文献
993.
J. Ellena G. Punte B. E. Rivero M. V. Remedi E. B. de Vargas R. H. de Rossi 《Journal of chemical crystallography》1995,25(12):801-805
The crystal structure of the title compound (C11H13N3O4) has been determined by single-crystal X-ray diffraction. The compound is monoclinic, space group P21/n, witha=9.968(2),b=9.156(2),c=13.249(2)Å, =102.05(2)°, andD
x=1.563 gcm–3 forZ=4. The aromatic ring shows a slight boat deformation. Theo- andp-NO2 groups are twisted out of the plane of the phenyl ring by 39.0(2)° and 4.4(1)°, respectively. The piperidine ring exhibits a slightly deformed chair conformation. Short C–H...O intermolecular contacts stabilize the three dimensional structure. UV and NMR data indicate that the molecule in solution presents a conformation similar to that of the the solid state. 相似文献
994.
The temperature dependence of the homogeneous line width (Γh) of the R-line of Cr3+ in 4ZnO·3B2O3 glass in the region between 15 K and room temperature has been measured. We found that Γh has a T 2 dependence down to approximately 30 K. Below 30 K the data do not follow the power law, T 2. The results are compared with those of Cr3+ in mullite and ED2 silicate glasses where the crossover was observed at about 80 K and with the data for Eu3+ in zinc borate and other glasses. The comparison indicates that the local environment affects Γh. In fact, the Cr3+ ions appear to form more defined complexes with the oxygen ligands than do the Eu3+ ions, which have a larger distribution of sites in the glass. 相似文献
995.
Athanasia Pavlopoulou Seyedehsadaf Asfa Evangelos Gioukakis Ifigeneia V. Mavragani Zacharenia Nikitaki Il Takan Jean-Pierre Pouget Lynn Harrison Alexandros G. Georgakilas 《Molecules (Basel, Switzerland)》2021,26(24)
Different types of DNA lesions forming in close vicinity, create clusters of damaged sites termed as “clustered/complex DNA damage” and they are considered to be a major challenge for DNA repair mechanisms resulting in significant repair delays and induction of genomic instability. Upon detection of DNA damage, the corresponding DNA damage response and repair (DDR/R) mechanisms are activated. The inability of cells to process clustered DNA lesions efficiently has a great impact on the normal function and survival of cells. If complex lesions are left unrepaired or misrepaired, they can lead to mutations and if persistent, they may lead to apoptotic cell death. In this in silico study, and through rigorous data mining, we have identified human genes that are activated upon complex DNA damage induction like in the case of ionizing radiation (IR) and beyond the standard DNA repair pathways, and are also involved in cancer pathways, by employing stringent bioinformatics and systems biology methodologies. Given that IR can cause repair resistant lesions within a short DNA segment (a few nm), thereby augmenting the hazardous and toxic effects of radiation, we also investigated the possible implication of the most biologically important of those genes in comorbid non-neoplastic diseases through network integration, as well as their potential for predicting survival in cancer patients. 相似文献
996.
We investigated the heterogeneous processes that contribute towards the formation of N2O in an environment that comes as closely as possible to exhaust conditions containing NO and SO2 among other constituents. The simultaneous presence of NO, SO2, O2, and condensed phase water in the liquid state has been confirmed to be necessary for the production of significant levels of N2O. The maximum rate of N2O formation occurred at the beginning of the reaction and scales with the surface area of the condensed phase and is independent of its volume. The replacement of NO by either NO2 or HONO significantly increases the rate constant for N2O formation. The measured reaction orders in the rate law change depending upon the choice of the nitrogen reactant used and were fractional in some cases. The rate constants of N2O formation for the three different nitrogen reactants reveal the following series of increasing reactivity: NO < NO2 < HONO, indicating the probable sequential involvement of those species in the elementary reactions. Furthermore, we observed a complex dependence of the rate constant on the acidity of the liquid phase where both the initial rate as well as the yield of N2O are largest at pH=0 of a H2SO4/H2O solution. The results suggest that HONO is the major reacting N(III) species over a wide range of acidities studied. The N2O formation in synthetic flue gas may be simulated using a relatively simple mechanism based on the model of Lyon and Cole. The first step of the complex overall reaction corresponds to NO oxidation by O2 to NO2 mainly in the gas phase, with the presence of both H2O and active surfaces significantly accelerating NO2 production. Subsequently, NO2 reacts with excess NO to obtain HONO which reacts with S(IV) to result in N2O and H2SO4 through a complex reaction sequence probably involving nitroxyl (HON) and its dimer, hyponitrous acid. © 1997 John Wiley & Sons, Inc. Int J Chem Kinet: 29 : 869–891, 1997. 相似文献
997.
998.
A comprehensive investigation of the photopolymerization in microheterogeneous structure is carried out with a view to elucidate the role played by the excited states in the initiation process. The radical initiation of methyl methacrylate in either anionic or cationic micelles or of acrylamide in reverse microemulsion is thus examined by UV spectroscopy, steady state photolysis and time resolved laser spectroscopy. The question of the localization of the initiator is dealt with special attention. Moreover, the influence of several parameters is also considered (concentration of reactants, incident light intensity, temperature or presence of external magnetic field). This contribution demonstrates the importance of a general approach involving a thorough knowledge of the elementary steps of initiation in the understanding of any polymerization conducted in a microheterogeneous medium. 相似文献
999.
Equilibrium stress-strain relationships in uniaxial extension for high cis-1,4-polyisoprene (Shell IR 307) networks were obtained by extrapolation of relaxation measurements to infinite time through a Bernstein-Kearsley-Zapas (BKZ) constitutive equation. Three series of networks were investigated, each series being characterized by its polymer precursor molecular weight. The influence of cross-linking density was studied through varying amounts of dicumyl peroxide as cross-linking agent. These results were used to test Flory and Erman's recent molecular theory of networks with constraints on junctions. Swelling equilibrium experiments with benzene and cyclohexane were performed on these networks and were in agreement with the mechanical analysis. The polymer-solvent interaction parameter for the system cis-polyisoprene + cyclohexane was estimated to be 0.31 at 20°C in the range 0 to 0.2 of polymer volume fraction. 相似文献
1000.
A general synthesis of various polyazaphosphorus macrocycles involving [1 + 1], [2 + 2], or [3 + 3] cyclocondensations is reviewed, as well as the attempted synthesis of cryptands. Selective reduction (imino functions) methylation (PS groups), silylation (PO groups) are reported. Preparations of some macrocycle complexes are described. 相似文献