The successful postfunctionalization of multiarm star polystyrene (PS) with pentafluorophenyl and allyl moieties at the periphery is demonstrated employing modular thiol‐para‐fluoro and photoinduced ...radical thiol‐ene double “click” reactions, respectively. α‐Fluoro and α‐allyl functionalized PS (α‐fluoro‐PS and α‐allyl‐PS) are in situ prepared by atom transfer radical polymerization of styrene and their mixture is used as macroinitiator in a crosslinking reaction with divinyl benzene (DVB) yielding (fluoro‐PS)m–polyDVB–(allyl‐PS)m multiarm star polymer. It is found that the multiarm star polymer includes nearly identical number of arms possessing pentafluorophenyl and allyl moieties at the periphery. The obtained multiarm star polymer is then reacted with 1‐propanethiol through thiol‐para‐fluoro “click” reaction to give (propyl‐PS)m–polyDVB–(allyl‐PS)m multiarm star polymer, which is subsequently reacted with N‐acetyl‐l‐cysteine methyl ester via radical thiol‐ene “click” reaction in order to give well‐defined heterofunctionalized (propyl‐PS)m–polyDVB–(cysteine‐PS)m multiarm star polymer, with higher molecular weight and narrow molecular weight distribution. Multiarm star polymers are characterized by using viscotek triple detection gel permeation chromatography, 1H, and 19F NMR.
Multiarm star polystyrene (PS) with pentafluorophenyl and allyl moieties at the periphery is prepared through the cross‐linking reaction of α‐fluoro and α‐allyl functionalized PS and divinyl benzene (DVB) yielding (fluoro‐PS)m–polyDVB–(allyl‐PS)m multiarm star polymer. Orthogonal thiol‐para‐fluoro and photoinduced radical thiol‐ene double “click” reactions are successfully employed for the postfunctionalization of the obtained star polymer.
To increase the drug loading and prolong the drug release time, novel hollow organic/inorganic hybrid nanoparticles based on dextran-b-poly(L-glutamate-graft-3-mercaptopropyltrimethoxysilane) ...(Dex-b-P(ALG-g-MTPMS)) were prepared. First, a polysaccharide block polypeptide diblock copolymer, dextran-block-poly(γ-allyl-L-glutamate) (Dex-b-PALG) bearing allyl side-groups, has been synthesized by the combination of ring-opening polymerization and alkyne-azide 2 + 3 Huisgen's cycloaddition. Next, the allyl side-groups residing in the poly(γ-allyl-L-glutamate) block were further functionalized with 3-mercaptopropyltrimethoxysilane(MPTMS) by radical “thiol-ene” addition reactions. Finally, after a sol-gel process of the obtained copolymers, the novel organic/inorganic hybrid nanoparticles were prepared. The molecular structures, physicochemical, and self-assembly of these copolymers were characterized through FTIR, 1H NMR, dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The cross-linked hybrid nanoparticles have a higher drug loading ability and slower release rate as compared to the uncross-linked counterparts. The MTT evaluation demonstrated that the organic/inorganic hybrid nanoparticles with good biocompatibility.
With the increasing capability of software and hardware, mobile devices especially smartphones are changing the way of peoples’ communication and living styles. For the sake of convenience, people ...often store a lot of personal data like images on the device and use it for completing sensitive tasks like payment and financial transfer. This makes data protection more important on smartphones. To secure the device from unauthorized access, one simple and efficient method is to design a device or screen unlock mechanism, which can authenticate the identity of current user. However, most existing unlock schemes can be compromised if an attacker gets the correct pattern. In this work, we advocate that behavioral biometrics can be useful to improve the security of unlock mechanisms. We thus design DCUS, a double-click-based unlocking scheme on smartphones, which requires users to unlock the device by double clicking on the right location on an image. For user authentication, our scheme needs to check the selected images, image location and double-click patterns. In the evaluation, we perform a user study with 60 participants and make a comparison between our scheme and a similar unlock scheme. With several typical supervised classifiers, it is found that participants can perform well under our scheme.
In electrical installations, each working zone and each source node present a kit of operating instructions as a logic gene. Previous papers have introduced a new approach and a language of a ternary ...code for operational procedures (Parise program). This paper deals with some comments on definitions and the syntax of the operational language. The same status of switching defines working zones or nodes by double operating value, free value, and packed value, thereby discriminating between decision and execution, and executed act from verification. The recommended command is a double click. The instructions have to be assembled like in a genetic cryptogram in the context of an electrical power system and of its architecture and constitution. They describe the complete and reversible evolution of the operational procedures for safe transition from a one set of switching configuration to another ( waves of safe sets ). Transitions maps are introduced to assist in the elaboration of operational procedures and to help the training of operators, their competence, and performance. These maps are specialized for the operational procedures more than the Karnaugh maps of digital electronics. On the basis of the logic gates, the basic equivalent mechanical connectives are defined to guide the operational procedures. A switching simulator based on electronic gates can be very useful for verifying the effects of any set of switching operations, adopting for commands the double click.
A class of well-defined dendritic star polymers with poly (ε-caprolactone) (PCLs) on the periphery has been prepared via one-pot double click reactions (Cu-catalyzed azide/alkyne click chemistry, ...i.e., CuAAC and Diels–Alder 4+2 cycloaddition reactions). The predecessors for Diels–Alder reaction, maleimide end-functionalized PCLs were produced by ring-opening polymerization (ROP). Obtained dendritic star polymers were characterized by
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H NMR, size exclusion chromatography (SEC), UV/vis, and fluorescence spectroscopy.
In this study, graft copolymers with regular graft points containing polystyrene (PS) backbone and poly(methyl methacrylate) (PMMA), poly(tert-butyl acrylate) (PtBA), or poly (ethylene glycol) (PEG) ...side chains were simply achieved by a sequential double polymer click reactions. The linear α-alkyne-ω-azide PS with an anthracene pendant unit per chain was produced via atom transfer radical polymerization of styrene initiated by anthracen-9-ylmethyl 2-((2-bromo-2-methylpropanoyloxy)methyl)-2-methyl-3-oxo-3-(prop-2-ynyloxy) propyl succinate. Subsequently, the azide-alkyne click coupling of this PS to create the linear multiblock PS chain with pendant anthracene sites per PS block, followed by Diels-Alder click reaction with maleimide end-functionalized PMMA, PtBA, or PEG yielded final PS-g-PMMA, PS-g-PtBA or PS-g-PEG copolymers with regular grafts, respectively. Well-defined polymers were characterized by ¹H NMR, gel permeation chromatography (GPC) and triple detection GPC.
In the P
50 gating or conditioning-testing paradigm in the rat, two identical click stimuli are presented with an inter-click interval of 500 ms. The reaction towards the second click, as measured ...with evoked potentials, is reduced in respect to that towards the first click; this phenomenon is called sensory gating. In the present experiments, the inter-click interval was varied systematically and auditory evoked potentials were measured. Sensory gating was found to occur only at intervals between 500 and 1000 ms, but not at longer intervals. Fos immunohistochemistry was then performed using two groups of rats exposed to double clicks: the inter-click interval was 500 ms in the experimental group and 2500 ms in the control group. Fos induction was analyzed in selected brain structures. In the auditory pathways, Fos-immunoreactive neurons were found in both groups of rats in the inferior colliculus and medial geniculate body. Fos-immunoreactive cells were also examined in the septum and hippocampus. In the ventral part of the lateral septal nucleus, the labeled neurons were significantly fewer in the experimental animals compared to the control group. Smaller and non-significant quantitative differences of Fos-positive neurons were documented in the medial septum and hippocampal CA1 region. These data point out a selective decrease in the lateral septum of Fos induced by auditory sensory gating, and suggest an involvement of this structure, and possibly of other parts of the septo-hippocampal system, in sensory gating mechanisms. The results might be relevant for theories on sensory gating deficits in schizophrenia.
This chapter highlights the primitives that make up the basic language of interaction. If one is building a top platform, some of those primitives may have been defined already, but there is no rule ...that one must use them. In truth, most of the UI toolkits and platforms designed for touch either contain only a very small set of primitives, or they have the wrong ones. The building blocks of an interaction language are what are referred as primitives. Modern software design is divided up into professions, often distinguished as information architecture, interaction design, and visual design. None of these operate at a sufficiently low level to create designs for new technologies. The vast majority of designers has never considered the fundamental mechanics of a link, or a click. This concept was so ingrained in their understanding of computers that they think of it as axiomatic. Click has become a part of the language spoken by users of interactive technologies.
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