Search results for "Surfaces"
showing 10 items of 2837 documents
Hydrogen-bonded dimers of a thiacalixarene substituted by carbamoylmethylphosphineoxide groups at the wide rim.
2006
A thiacalix[4]arene derivative bearing four carbamoylmethylphosphineoxide groups at the wide rim forms hydrogen-bonded, dimeric capsules with S8 symmetry in the crystalline state and in apolar solvents, where the inclusion of cationic guests could be proved by 1H NMR and ESI mass spectra.
Optical Gating of Photosensitive Synthetic Ion Channels
2011
4-oxo-4-(pyren-4-ylmethoxy) butanoic acid is used as a photolabile protecting group to show the optical gating of nanofluidic devices based on synthetic ion channels. The inner surface of the channels is decorated with monolayers of photolabile hydrophobic molecules that can be removed by irradiation, which leads to the generation of hydrophilic groups. This process can be exploited in the UV-light-triggered permselective transport of ionic species in aqueous solution through the channels. The optical gating of a single conical nanochannel and multichannel polymeric membranes is characterised experimentally and theoretically by means of current-voltage and selective permeation measurements,…
Slippage of water over hydrophobic surfaces
1999
When water is confined between hydrophobic surfaces, its flow properties are significantly different from those in bulk, or between hydrophilic surfaces. These changes (that are usually ignored) may be interpreted in terms of hydrophobic slippage. This chapter reviews recent developments in the hydrodynamics of water confined between solid hydrophobic surfaces, emphasizing the main experimental facts, theoretical models suggested, and different aspects of thin film drainage. The relevance of slippage in hydrophobic surface force measurements and on the coagulation rate of hydrophobic particles is discussed.
Electrochemical Monitoring of Compartmentalization Effects in the Stability of Meisenheimer Anions Supported in Hydrotalcite and X and Y Zeolites
2005
Meisenheimer anions (MS - ) derived from 2,4-dinitroaniline are stabilized into Li + - and Na + -exchanged zeolites X and Y forming alkali ion-MS ion pairs. Upon attachment of the zeolites to polymer film electrodes immersedinto Et 4 N + /MeCN and Li + /MeCN electrolytes, boundary-associated MS - ions display two oxidation processes at +0.40 and +0.65 V vs. AgCl/Ag. This response sharply contrasts with that recorded for MS - in solution and incorporated within hydrotalcite, for which a unique oxidation peak at +0.35 V is recorded. The electrochemistry of zeolite-associated MS - can be described in terms of an unusual electron-transfer/ chemical reaction/electron-transfer/comproportionation …
Neutron-Induced Effects on a Self-Refresh DRAM
2022
International audience; The field of radiation effects in electronics research includes unknowns for every new device, node size, and technical development. In this study, static and dynamic test methods were used to define the response of a self-refresh DRAM under neutron irradiation. The neutron-induced effects were investigated and characterised by event cross sections, soft-error rate, and bitmaps evaluations, leading to an identification of permanent and temporary stuck cells, single-bit upsets, and block errors. Block errors were identified in different patterns with dependency in the addressing order, leading to up to two thousand faulty words per event, representing a real threat fr…
Some families of big and stable bundles on $K3$ surfaces and on their Hilbert schemes of points
2021
Here we investigate meaningful families of vector bundles on a very general polarized $K3$ surface $(X,H)$ and on the corresponding Hyper--Kaehler variety given by the Hilbert scheme of points $X^{[k]}:= {\rm Hilb}^k(X)$, for any integer $k \geqslant 2$. In particular, we prove results concerning bigness and stability of such bundles. First, we give conditions on integers $n$ such that the twist of the tangent bundle of $X$ by the line bundle $nH$ is big and stable on~$X$; we then prove a similar result for a natural twist of the tangent bundle of $X^{[k]}$. Next, we prove global generation, bigness and stability results for tautological bundles on $X^{[k]}$ arising either from line bundles…
New Internal-Charge-Transfer Second-Order Nonlinear Optical Chromophores Based on the Donor Ferrocenylpyrazole Moiety
2016
A series of new N-arylated ferrocenepyrazole structures, carrying different donor or acceptor substituents in the para position of the aryl ring, has been synthesized by the Chan-Lam cross-coupling reaction. The nonplanar geometric molecular structure of some of these chromophores together with their crystal packing was determined by X-ray diffraction, and the HOMO and LUMO energy levels were evaluated by electrochemical and optical measurements and by density functional theoretical (DFT) calculations. By the investigation of solvent effects and time-dependent DFT (TD-DFT) calculations, the intense electronic absorption band around 270-310 nm was confirmed to be an internal-chargetransfer (…
Site-specific halloysite functionalization by polydopamine: A new synthetic route for potential near infrared-activated delivery system
2022
Abstract Halloysite nanotubes (HNTs) represent a versatile core structure for the design of functional nanosystems of biomedical interest. However, the development of selective methodologies for the site-controlled functionalization of the nanotubes at specific sites is not an easy task. This study aims to accomplish a procedure for the site-selective/specific, “pin-point”, functionalization of HNTs with polydopamine (HNTs@PDA). This goal was achieved, at pH 6.5, by exploiting the basicity of ZnO nanoparticles anchored on the HNTs external surface (HNTs@ZnO) to induce a punctual polydopamine polymerization and coating. The morphology and the chemical composition of the nanomaterial was demo…
A gated material as immunosensor for in-tissue detection of IDH1-R132H mutation in gliomas
2021
[EN] A nanodevice consisted on nanoporous anodic alumina (NAA) supports functionalized with specific and selective antibody-based gatekeepers for the detection of IDH1-R132H mutant enzyme is here reported. Molecular profile and tissue mutations of the tumours (such as IDH1/IDH2 mutations in gliomas) are a great source of information that already make a difference in terms of prognosis and prediction of response to combined therapy. However, standardized methodologies to determine this mutation are time-consuming and cannot provide information before or during surgical intervention, which significantly limits their utility in terms of intraoperative decisionmaking. To solve this limitation, …
Gated mesoporous silica nanoparticles for the controlled delivery of drugs in cancer cells
2015
In recent years, mesoporous silica nanoparticles (MSNs) have been used as effective supports for the development of controlled-release nanodevices that are able to act as multifunctional delivery platforms for the encapsulation of therapeutic agents, enhancing their bioavailability and overcoming common issues such as poor water solubility and poor stability of some drugs. In particular, redox-responsive delivery systems have attracted the attention of scientists because of the intracellular reductive environment related to a high concentration of glutathione (GSH). In this context, we describe herein the development of a GSH-responsive delivery system based on poly(ethylene glycol)- (PEG-)…