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.
Thiasilacyclopentane (TSCP) and azasilacyclopentane (ASCP) heteroatom cyclics have proven capable of rapidly converting hydroxylated surfaces to functionalized surfaces in inorganic click reactions. ...In this work we demonstrate that the use of these reagents can be extended to "simultaneous double-clicking" when both inorganic and organic substrates are present at the onset of the reaction. The simultaneous double-click depends on a first click with an inorganic substrate which results in the reveal of a cryptic mercaptan or secondary amine group which can then participate in a second click with an organic substrate. TSCPs and ASCPs can take part in tandem double-click reactions in which the organic substrate is added to the reaction mixture after the initial inorganic click reaction is completed. Additionally ASCPs with exocyclic functionality, specifically N-alkenyl-, N-aminoalkyl, and N-alkynyl-ASCPs, are shown to be options for tandem double-clicking in which functionalization proceeds in two independent steps and the sequence of the double-click reaction can be reversed.
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.
This chapter takes the reader through a brief history of search engine development and demonstrates that the search engine did not inherently have economic value. On the contrary, its origin was ...deeply rooted in non-commercial academic spaces and users and some early search engine firms opposed the idea of ads-based search engines, believing that search results should not be influenced by commerce. How then has this shift to an ads-based business model occurred? What factors and conditions have driven search engine technologies that were outside the money economy into the marketplace? The chapter answers these questions as it illustrates the process of the commodification of search in order to show the possibility of decommodification.
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.
This paper analyzes the failure of a double-click wake-up failure under the strong light of a TDDI product, and finally clarifies the impact of the product's special panel design and process ...fluctuations on this problem, and uses Two method, adjustment of driving signal or optimization of the touch algorithm, to improve this failure effectively. At the same time, it also provides a preventive advice for a new TDDI products.
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