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Coronavirus disease 2019 (COVID-19) is currently a pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 are directly associated with hyper-activation of innate immune response that excessively produce pro-inflammatory cytokines and induce cytokine storm, leading to multi-organ-failure and significant morbidity/mortality. Currently, several antiviral drugs such as Paxlovid (nirmatrelvir and ritonavir) and molnupiravir are authorized to treat mild to moderate COVID-19, however, there are still no drugs that can specifically fight against challenges of SARS-CoV-2 variants.

Aqueous rechargeable zinc batteries (ZBs) have received considerable attention recently for large-scale energy storage systems in terms of rate performance, cost, and safety. Nevertheless, these ZBs still remain a subject for investigation, as researchers search for cathode materials enabling high performance. Among the various candidate cathode materials for ZBs, quinone compounds stand out as candidates because of their high specific capacity, sustainability, and low cost. Quinone-based cathodes, however, suffer from the critical limitation of undergoing dissolution during battery cycling, leading to a deterioration in battery life. To address this problem, we have introduced a redox-active triangular phenanthrenequinone-based macrocycle (PQ-Δ) with a rigid geometry and layered superstructure. Notably, we have confirmed that Zn2+ ions, together with H2O molecules, can be inserted into the PQ-Δ organic cathode, and, as a consequence, the interfacial resistance between the cathode and electrolytes is decreased effectively. Density functional theory calculations have revealed that the low interfacial resistance can be attributed mainly to decreasing the desolvation energy penalty as a result of the insertion of hydrated Zn2+ ions in the PQ-Δ cathode. The combined effects of the insertion of hydrated Zn2+ ions and the robust triangular structure of PQ-Δ serve to achieve a large reversible capacity of 210 mAh g-1 at a high current density of 150 mA g-1, along with an excellent cycle-life, that is, 99.9% retention after 500 cycles. These findings suggest that the utilization of electron-active organic macrocycles, combined with the low interfacial resistance associated with the solvation of divalent carrier ions, is essential for the overall performance of divalent battery systems.

Theoretical and numerical studies were conducted to investigate the transitional interpillar spacing for dual-scale structures, where wetting transition between the Wenzel and Cassie-Baxter states occurs in the primary and secondary pillars. A theoretical formula was derived for the transitional interpillar spacing based on the continuum picture of water. Molecular dynamics (MD) simulations were carried out by varying the interpillar spacing for the primary pillars for single- and dual-scale structures with various pillar heights. The results obtained from the theoretical formula agreed reasonably well with the results obtained from MD simulations, especially when the primary pillar height was relatively high. The transitional interpillar spacing increases as the pillar height and the number of secondary pillars increase. The effect of the secondary pillars on the transitional interpillar spacing was also evaluated using the difference in the grand potentials between the Wenzel and Cassie-Baxter states. These results show that the dual-scale structures increase the transitional interpillar spacing with an increase in the surface hydrophobicity.

The present study investigated the dynamic behavior of a nanosized water droplet on a flat and stepped surface using molecular dynamics simulations. The effects of a wetting gradient associated with the surface and the step height of a stepped surface on the dynamic behavior of the water droplet were considered in this study. The dynamic behaviors of the water droplet were described quantitatively upon analyzing the transient variation of the adhesion energy and the position of the water droplet along with the time required to climb the step. The water droplet moved smoothly along the surface with an increasing wetting gradient. On the other hand, the step obstructed the water droplet from climbing the step as the step height increases. The dynamic behavior of the water droplet depending on the variation of the normalized step height and the differences in adhesion energies between the different surfaces was classified into three types, namely, (1) fully climbing the step, (2) partially climbing the step, and (3) being blocked by the step. In the case in which the water droplet fully climbs the step, the time taken for the water droplet to fully climb the step showed a non-monotonic pattern as the step height increases.

Conjugated microporous polymers (CMPs) offer a unique structure integrating π- conjugated backbone into a porous network for the simultaneous transport of charges and materials. However, tuning electronic properties of CMPs so far has been limited to an approach of varying the monomers, and the precious metal catalysts are inevitably needed for the C–C coupling reaction. Here, we present a powerful strategy to synthesize CMPs and precisely tune their optical band gap and surface area through metal-free in situ cyclization reaction controlled by the acid strength of acid catalysts. Notably, the optical band gap of CMPs showed a linear relationship with the pKa of acid catalysts, which provides us with the ability to obtain the desired band gap between 2.07 and 3.35 eV, falling in the range of the visible solar spectrum. Moreover, CMPs exhibited excellent textural properties such as microporosity and high specific surface area.

A numerical study was carried out using a molecular dynamics program to examine the wetting characteristics of nano-sized water droplets on surfaces with various pillar surface fractions under different conditions. Square-shaped pillars had surface fractions that increased from 11.1 % to 69.4 %. The pillars had 4 different heights and 3 different surface energies. When the pillar surface fraction changed, the contact angle of a water droplet also changed due to the attraction between the droplet and the pillar surface or the inner attraction of the water molecules. The pillar height also has different effects on the water droplet depending on the magnitude of surface energy.

Silicon (Si) anode is among the most promising candidates for the next-generation high-capacity electrodes in Li-ion batteries owing to its unparalleled theoretical capacity (4200 mA h g−1 for Li4.4Si) that is approximately 10 times higher than that of commercialized graphitic anodes (372 mA h g−1 for LiC6). The battery community has witnessed substantial advances in research on new polymeric binders for silicon anodes mainly due to the shortcomings of conventional binders such as polyvinylidene difluoride (PVDF) to address problems caused by the massive volume change of Si (300%) upon (de)lithiation. Unlike conventional battery electrodes, polymeric binders have been shown to play an active role in silicon anodes to alleviate various capacity decay pathways. While the initial focus in binder research was primarily to maintain the electrode morphology, it has been recently shown that polymeric binders can in fact help to stabilize cracked Si microparticles along with the solid–electrolyte-interphase (SEI) layer, thus substantially improving the electrochemical performance. In this review article, we aim to provide an in-depth analysis and molecular-level design principles of polymeric binders for silicon anodes in terms of their chemical structure, superstructure, and supramolecular interactions to achieve good electrochemical performance. We further highlight that supramolecular chemistry offers practical tools to address challenging problems associated with emerging electrode materials in rechargeable batteries.

A stretchy binder protects the silicon A challenge in using silicon particles for lithium batteries is that the large volume changes during charge-discharge cycling cause the particles to fracture, which builds up an insulating interface layer. Choi et al. show that traditional binder materials used to cushion the silicon particles can be improved by adding small amounts of polyrotaxanes (see the Perspective by Ryu and Park). The molecules consist of multiple rings that are strung along a linear segment and stoppered at each end. Some of the rings are anchored to the polymer binder, whereas others float freely, yielding a highly mobile but connected network that anchors the binder, and thus the silicon particles, together. Science , this issue p. 279 ; see also p. 250

Although being incorporated in commercial lithium‐ion batteries for a while, the weight portion of silicon monoxide (SiOx, x ≈ 1) is only less than 10 wt% due to the insufficient cycle life. Along this line, polymeric binders that can assist in maintaining the mechanical integrity and interfacial stability of SiOx electrodes are desired to realize higher contents of SiOx. Herein, a pyrene–poly(acrylic acid) (PAA)– polyrotaxane (PR) supramolecular network is reported as a polymeric binder for SiOx with 100 wt%. The noncovalent functionalization of a carbon coating layer on the SiOx is achieved by using a hydroxylated pyrene derivative via the π–π stacking interaction, which simultaneously enables hydrogen bonding interactions with the PR– PAA network through its hydroxyl moiety. Moreover, the PR's ring sliding while being crosslinked to PAA endows a high elasticity to the entire polymer network, effectively buffering the volume expansion of SiOx and largely mitigating the electrode swelling. Based on these extraordinary physicochemical properties of the pyrene–PAA–PR supramolecular binder, the robust cycling of SiOx electrodes is demonstrated at commercial levels of areal loading in both half‐cell and full‐cell configurations.

A numerical study was carried out to investigate the wetting characteristics of both an orthogonal type surface and a wavy type surface at the nano-scale by means of the molecular dynamics simulation method. In this study, the contact angles of a droplet on orthogonal type surfaces and on wavy type surfaces were used to compare the wetting characteristics of orthogonal stripe-patterned surfaces with those of wavy-patterned surfaces. The water droplet is less affected by the various orthogonal type and wavy type surfaces when the primary texture height of the structure and surface energy are relatively low. However, as the primary texture height of the structure and surface energy increase, the results of a one directional textured pattern is different from those of the dual direction textured pattern. In the cases of the orthogonal stripe-patterned surfaces and the wavy-patterned surfaces having a one directional pattern, the geometric difference indicates that the wavy type surface have a contact angle as much 85° higher than the orthogonal type surface. However, when comparing the orthogonal and wavy dual direction patterned surfaces, there is never more than 17° difference.

In this study, the static and dynamic behaviors of nano-scale water droplets on heterogeneous surfaces were investigated using molecular dynamics simulations. The surface consisted of a flat plate and pillar structures. The surface was designed with four pillar heights and three pillar characteristic energies. Simulations were first run so that the water droplet reached the static equilibrium state. Once the static water droplets were in Cassie-Baxter state, increasing the pillar height had very little effect on the contact angle. Droplets on the surface with the strongest pillar characteristic energy never reached the Cassie-Baxter state and contact angles tended to decrease with increasing pillar height. Then five forces were applied to the water droplets parallel to the surface to observe the dynamic behavior of the droplets. Then, the effect of the pillar characteristic energy on the behavior of the dynamic water droplet was discussed using the contact angle hysteresis (cosθ Re − cosθ Ad) as the pillar height and the magnitude of the applied force varied. When compared to the homogeneous cases, it was found that except at the lowest pillar height all of the lower pillar characteristic energy cases were hydrophobic and did not depend much on pillar height or magnitude of force. Whereas the higher pillar characteristic energy cases were generally hydrophilic and the hydrophobicity depended greatly on the magnitude of the force.

In this study, we report the results of molecular dynamics simulations (MD) for model systems of mid-size liquid n-alkanes (C12–C160 ) at several temperatures (~2700 K) in canonical ensembles to calculate structural and dynamic properties (viscosity η, self-diffusion constant D, and monomeric friction constant ζ). For the small n-alkanes for n ≤ 80, the chains are clearly , which leads to the conclusion that the liquid n-alkanes are far away from the Rouse regime, but for the n-alkanes for n ≥ 120, the chains are and they are Gaussian. It is found that the long chains of these n-alkanes at high temperatures show abnormalities in density, viscosity, and monomeric friction constant. The mass and temperature dependences of structural and dynamic properties (η, D, and ζ) are discussed.

We investigated the wetting characteristics of a water droplet on a heterogeneous pillared surface at the nano-scale including contact angle, molecule inflow percentage and density fields and compared them with the wetting characteristics of a water droplet on a homogeneous pillared surface. Molecular dynamics simulations were employed to analyze the wetting behavior of water droplets on surfaces with pillar structures by considering different potential energies including bond, angle, Lennard-Jones and Coulomb to calculate the interacting forces between water molecules and the surface. The heterogeneous surfaces considered had pillars with a different surface energy than the base surface. It was found that the difference in surface energy between the base surface and pillar had little effect on the hydrophobicity of the surface at low pillar heights. However cases with pillar heights over H = 4.24 A, the pillar surface energy has a larger effect on the molecule inflow percentage with the maximum differences in the range from 33.8% to 47.2% depending on the base surface energy. At a pillar height of H = 16.96 A, the pillar surface energy has a large effect on the contact angle of the water droplet with the maximum differences in the range from −26.1% to −40.62% depending on the base surface energy. There was a large variation in the contact angle of the droplet as the pillar height increased when there was a large difference in the surface energies between the base and the pillars.

We systematically investigate polysaccharide binders for high-capacity silicon anodes in lithium ion batteries to find critical factors for the binder function. Analogous to the millipede's strong adhesion based on adhesive pads located on each leg, xanthan gum exhibits the best performance by utilizing its double helical superstructure with side chains and ion–dipole interactions, revealing the great importance of the superstructure and charge interactions in the Si binder design.

We have fabricated a polymer light-emitting diode (PLED) from the conventional blue-emitting polymer, polyfluorene (PFO), by constructing a multilayer structure with non-metal ion containing water soluble non-conjugated polymer, polyurethane with F- ion (PU:F-), on the top of the PFO. The device with PU:F- layer shows a maximum luminance of 5294 cd/m2 at an applied voltage of 10 V while the one without PU:F- layer shows only 4439 cd/m2 at the same applied voltage. We propose the improvement of device performance with PU:F- layer was due to not only an effective hole blocking at the polymer-polymer interface but also increase of electric field strength with anode after electro-stactic repulsion between electrons from the cathod and anions from the water soluble polymer layer. We will discuss the effect of multilayer polymer structure in PLED in terms of current/voltage characteristics, luminance, and quantum efficiency related with the applied bias.

Despite their unparalleled theoretical capacity, lithium‐metal anodes suffer from well‐ known indiscriminate dendrite growth and parasitic surface reactions. Conductive scaffolds with lithium uptake capacity are recently highlighted as promising lithium hosts, and carbon nanotubes (CNTs) are an ideal candidate for this purpose because of their capability of percolating a conductive network. However, CNT networks are prone to rupture easily due to a large tensile stress generated during lithium uptake– release cycles. Herein, CNT networks integrated with a polyrotaxane‐incorporated poly(acrylic acid) (PRPAA) binder via supramolecular interactions are reported, in which the ring‐sliding motion of the polyrotaxanes endows extraordinary stretchability and elasticity to the entire binder network. In comparison to a control sample with inelastic binder (i.e., poly(vinyl alcohol)), the CNT network with PRPAA binder can endure a large stress during repeated lithium uptake–release cycles, thereby enhancing the mechanical integrity of the corresponding electrode over battery cycling. As a result, the PRPAA‐incorporated CNT network exhibits substantially improved cyclability in lithium–copper asymmetric cells and full cells paired with olivine‐LiFePO4, indicating that high elasticity enabled by mechanically interlocked molecules such as polyrotaxanes can be a useful concept in advancing lithium‐metal batteries.

E-mail: jenekhe@u.washington.eduReceived April 18, 2012, Accepted May 23, 2012New C60 fullerenes derivatives [G1]-C60 ( 1) and [G2]-C60 ( 2) comprising of phenylenevinylene bridges andphenylquinoline peripheral surface groups were synthesized by 1,3-dipolar cycloaddition reaction of fullereneC60 with azomethine ylide in situ generated from [Gx]-CHO dendrons (x = 1 and 2) and sarcosine.Key Words : C60 fullerenes, Oligoquinolie-functionalized fullerene, Phenylquinoline, Conjugated arylene vi-nylene dendronsIntroductionInterest in low cost and efficient conversion of sunlightinto electrical energy has lead to development of organicmaterials such as fullerenes and other conjugated polymers.Since discovery of C60 fullerene

The coupling reaction between 5-bromo-3-phenylbenzo[c]isoxazole and diphenylamine followed by further condensation with a mono-, di- or ter-acetyl aromatic compound in the presence of diphenyl phosphate at 145 o C gave a novel asymmetric diarylquinolines, oligoquinolines with diphenylamine endgroups, and a first generation quinoline dendrimer in 41-82% isolated yield. The electrochemical and photophysical properties of the oligoquinolines were characterized by cyclic voltammograms (CVs) and spectroscopy. All the quinolines emit bright sky blue light due to charge transfer from quinoline group to diphenly amine with very high quantum efficiency (> 90%). Organic light-emitting diodes (OLEDs) were fabricated using these quinolines as emitting materials. Among different device architectures explored, OLEDs with a structure of ITO/PEDOT (40 nm)/TAPC (15 nm)/D-A quinoline (40 nm)/TPBI (30 nm)/LiF (1 nm)/Al using TAPC as an electron blocking layer and TPBI as a hole blocking layer gave the best performance. A high external quantum efficiency in the range of 1.2-2.3% were achieved in all the quinolines with the best performance in BBQA(5). Our results indicate diarylamino-substituted oligoquinoline and dendrimer are promising materials for OLEDs applications.

We modified the surface of a polyvinyl alcohol (PVA) layer by self assembly monolayer technique using a fluorine substituted silane compound (1H,1H,2H,2H-perfluorooctyl-trichlorosilane: FTS) to protect a pentacene thin-film transistor (TFT) from O2 and H2O. Surface modified PVA showed very low surface energy with water contact angle of 106.2 degrees. Surface treatment of PVA layer on pentacene TFT device was done in toluene solvent and we did not observe any damage to the PVA layer or pentacene TFT devices during surface modification process. Pentacene TFT with surface modified PVA passivation layer exhibited very stable TFT operation with almost no field effect mobility drop or threshold voltage shift up to 400 hrs. The performance of unpassivated OTFTs exponentially degraded and almost failed in 290 hrs. We propose that modified PVA layer can be used as a good passivation layer for oxygen and water in OTFT.

Conjugated quinolines were synthesized by the reaction between aminobenzophenones and various diacetyl compounds such as diacetyl phenothiazine, diacetylcarbazole, and diacetyl biphenyl and di/triacetyl benzene under solvent-free microwave irradiation in 12–98% yields. Symmetrically substituted oligoquinolines were predominantly formed within 12 min in the presence of 0.5 equiv of diphenylphosphate catalyst without any solvent.

Microwave-assisted Michael reaction between EMME and various amines such as diphenylamine, 4-methyl-N-phenylbenzenamine, N-phenylnaphthalen-1-amine, dihexylamine, diisopropylamine, and 4-nitrobenzenamine were described. Solvent-free conditions on alumina as solid support in the presence of catalysts gave moderate to good yields (55 - 93%) of diethylmalonate analogues having enamine moieties under focused microwave irradiation.

Highly fluorescent isomeric donor–acceptor molecules, 2-(4-phenyl-2-quinolyl)-10-methylphenothiazine (2PQMPT) and 3-(4-phenyl-2-quinolyl)-10-methylphenothiazine (3PQMPT), were synthesized in high yields (>85%) and found to exhibit a factor of 2.4 disparity in electroluminescence efficiency. Bright (10,000–25,000 cd/m2) and efficient (3.6–8.7 cd/A) green organic light-emitting diodes were realized from the two donor–acceptor molecules. The new molecules are good model systems for the study of structure–property relationships of donor–acceptor molecules for organic light-emitting diodes.

Summary This presentation describes a fast and facile microwaveenhanced N -alkenylation synthesis between sulfur-contain-ing lactam and various aldehydes such as n -propanal, iso-propanal, n -butanal, n -hexanal, n -octanal and phenylacet-aldehyde in 32 to 86% yields. In order to explain the con-formational properties of E/Z isomers, we used the couplingconstant ( J ) of 1 H and 2-D NOESY NMR techniques. In allcases, E isomers were predominantly produced. We expectthese new N -alkenyl pyrrolidine-2-thiones to have interest-ing applications for the protection of functionalized thio-lactams. Consequently, we are currently expanding ourresults using the advantages of microwave irradiation. Experimental Section Pyrrolidin-2-one, Lawesson’s reagent, p -toluenesulfonicacid monohydrate (98.5%), bentonite, K 10, Al 2 O 3, n -pro-panal, isopropanal, n -butanal, n -hexanal, n -octanal andphenylacetaldehyde were purchased from Sigma-Aldrich(Korea) and used as received. Toluene, chlorobenzene and

In an early stage of design process for the lower arm in automobile suspension module, an easy and fast FE modeling, static and durability analysis supported by parametric study considering its geometric changes are required. The FE modeling support system has been developed, which is implemented on the platform of MSC.Patran. The CAD file produced by taking into account of automatic 3D parametric model in CATIA V5 can be transferred to this system. For the process automation of various design activities including the parametric study, human interactions are excluded practically, in which all processes are dealt with the XML-wrapper, and in- and output data are linked each other and treated in the engineering data management. The developed FE modeling support system reduces time and cost to design and analyze engineering problems.

We report supramolecular cross-linking of polymer binders via dynamic host–guest interactions between hyperbranched β-cyclodextrin polymer and a dendritic gallic acid cross-linker incorporating six adamantane units for high-capacity silicon anodes. Calorimetric analysis in the solution phase indicates that the given host–guest complexation is a highly spontaneous and enthalpically driven process. These findings are further verified by carrying out gelation experiments in both aqueous and organic media. The dynamic cross-linking process enables intimate silicon–binder interaction, structural stability of electrode film, and controlled electrode–electrolyte interface, yielding enhanced cycling performance. Control experiments using both α, γ-CDp with different cavity sizes and a guest molecule incorporating a single adamantane unit verified that the enhanced cycle life originates from the host–guest interaction between β-cyclodextrin and adamantane. The impact of the dynamic cross-linking is maximized at an optimal stoichiometry between the two components. Importantly, the present investigation proves that the molecular-level tuning of the host–guest interactions can be translated directly to the cycling performance of silicon anodes. NPRP grant (NPRP 7-301-2-126) from the Qatar National Research Fund (a member of Qatar Foundation). Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (2013R1A1A1012282). J.W.C. acknowledges support through the National Research Foundation of Korea (NRF) grant funded by the Korean government (MEST) (NRF-2012-R1A2A1A01011970). National Research Foundation of Korea (NRF) grant funded by the Korean government (MEST) (NRF-2014R1A4A1003712 and BK21 PLUS program). Scopus

The siRNA silencing approach has long been used as a method to regulate the expression of specific target genes in vitro and in vivo. However, the effectiveness of delivery and the nonspecific immune-stimulatory function of siRNA are the limiting factors for therapeutic applications of siRNAs. To overcome these limitations, we developed self-assembled micelle inhibitory RNA (SAMiRNA) nanoparticles made of individually biconjugated siRNAs with a hydrophilic polymer and lipid on their ends and characterized their stability, immune-stimulatory function, and in vivo silencing efficacy. SAMiRNAs form very stable nanoparticles with no significant degradation in size distribution and polydispersity index over 1 year. Overnight incubation of SAMiRNAs (3 μm) on murine peripheral blood mononuclear cells did not cause any significant elaboration of innate immune cytokines such as TNF-α, IL-12, or IL-6, whereas unmodified siRNAs or liposomes or liposome complexes significantly stimulated the expression of these cytokines. Last, the in vivo silencing efficacy of SAMiRNAs was evaluated by targeting amphiregulin and connective tissue growth factor in bleomycin or TGF-β transgenic animal models of pulmonary fibrosis. Intratracheal or intravenous delivery two or three times of amphiregulin or connective tissue growth factor SAMiRNAs significantly reduced the bleomycin- or TGF-β-stimulated collagen accumulation in the lung and substantially restored the lung function of TGF-β transgenic mice. This study demonstrates that SAMiRNA nanoparticle is a less toxic, stable siRNA silencing platform for efficient in vivo targeting of genes implicated in the pathogenesis of pulmonary fibrosis.

The synthesis and photophysics of two new donor-acceptor conjugated A-B type copolymers based on conjugated 2,6-disubstitued-4-phenyl-quinoline and 2-substitued-4-phenyl-quinoline, and 9,9-dialkyl-fluorene linked through the 1,4 and 1,3,5 phenyl rings via the Friedlander condensation and Suzuki coupling reaction are presented. The band gap energy of the polymers 1 and 2 measured from the thin films were 430 nm and 380 nm corresponding to 2.88 eV and 3.26 eV, respectively. The photoluminescence (PL) spectra of the thin films of the polymers 1 and 2 showed maximum peaks at 427 and 397 nm corresponding to the deep blue and UV ranges respectively. The red shift of the polymer 1 relative to the polymer 2 can be accounted for by the increased conjugation length because the quinoline unit is oriented to include the phenyl ring in the backbone of polymer 1 . Both polymers have similar trends of irreversible oxidation. The ionization energy of polymers 1 and 2 were measured by cyclic voltammetry (CV) and were foun...

In this work, as a new flexible gate insulator of organic thin film transistor (OTFT) device, PMDA-ODA-type polyimide (PI) were inserted between ITO and pentacene layer using modified ionized cluster beam (MICB) deposition method. The grain size of pentacene layers deposited by MICB method on ordered PI substrates was bigger than those by using conventional deposition method. The grain growth effect could be a good clue to explain increased mobility of our devices with MICB-deposited PI gate insulator. Since the flexibility and elasticity of polymeric gate insulator and conducting electrodes are essential for fabrication of flexible displays, the results of this work could be used for developing flexible all-organic devices and displays.

Michael addition reaction between EMME and various O, S, N nucleophiles were investigated in the presence of catalysts such as KF, KOH, or K(OCCH3)3 under solvent‐free conditions either neat or on alumina as solid support. Compared to low reactivity of alcohols (40 to 80% yields according to aliphatic chain), aniline or thiophenol gave good to excellent yields (90–99%).

Three new electron-acceptor and light-emitting conjugated dendrimers, [G1-4Q], [G1-6Q], and [G2-12Q], based on a benzene core, poly(phenylenevinylene) dendrons, and diphenylquinoline peripheral groups have been synthesized, characterized, and used as emissive and electron-transport materials in efficient light-emitting diodes. All three dendrimers emit blue light (λmax = 414 nm) in solution with high fluorescence quantum yields in the 0.69−0.87 range and fluorescence lifetimes of 1.4−1.6 ns. In thin films the dendrimers emit yellow light with poor fluorescence efficiency, suggesting aggregation and excimer formation in the solid state. The dendrimers showed quasi-reversible electrochemical reduction with a formal potential of −2.0 V (vs SCE) and derived LUMO levels of 2.5−2.6 eV, implying that injected electrons are localized in the periphery of the dendrimers. As the emissive materials in light-emitting diodes, the dendrimers showed yellow electroluminescence the brightness and efficiency of which increa...

Hepatitis C virus (HCV) is a positive-strand RNA virus that encodes a helicase required for viral replication. Although HCV does not replicate through a DNA intermediate, HCV helicase unwinds both RNA and DNA duplexes. An X-ray crystal structure of the HCV helicase complexed with (dU) 8 has been solved, and the substrate-amino acids interactions within the catalytic pocket were shown. Among these, residues W501 and V432 were reported to have base stacking interactions and to be important for the unwinding function of HCV helicase. It has been hypothesized that specific interactions between the enzyme and substrate in the catalytic pocket are responsible for the substrate specificity phenotype. We therefore mutagenized W501 and V432 to investigate their role in substrate specificity in HCV helicase. Replacement of W501, but not V432, with nonaromatic residues resulted in complete loss of RNA unwinding activity, whereas DNA unwinding activity was largely unaffected. The loss of unwinding activity was fully restored in the W501F mutant, indicating that the aromatic ring is crucial for RNA helicase function. Analysis of ATPase and nucleic acid binding activities in the W501 mutant enzymes revealed that these activities are not directly responsible for the substrate specificity phenotype. Molecular modeling of the enzyme-substrate interaction at W501 revealed a putative π-facial hydrogen bond between the 2′-OH of ribose and the aromatic tryptophan ring. This evidence correlates with biochemical results suggesting that the π-facial bond may play an important role in the RNA unwinding activity of the HCV NS3 protein.

Thin polyimide films were deposited for hole blocking layer of EL device by the novel physical vapor deposition method, Ionized Cluster Beam Deposition (ICB). EL devices of Glass/ITO/PI/BEH-PPV/Al structure using spin coating and the ICB deposition technique were fabricated. By inserting a PI interlayer with various thickness and packing density, I–V and I–L characteristics, electroluminescence spectra and quantum efficiency of the devices were investigated in order to determine the role of the PI interlayer between ITO and BEH-PPV.

Covalent or Noncovalent? Systematic investigation of polymeric binders incorporating Meldrum's acid reveals most critical binder properties for silicon -anodes in lithium ion batteries, that is self-healing effect facilitated by a series of noncovalent interactions.

Cyclohexa-2,4-diene-1-one sulfone derivate undergoes ring cleavage to afford bis-amides containing a diene moiety on irradiation with visible light in the presence of various diamines.

A stable sulfone derivative of 2,4,6-trimethylcyclohexa-2,4-diene-1-one (7) undergoes facile ring cleavage under visible light to produce a ketene intermediate, which could be efficiently captured by amines to give amides even in the presence of competing nucleophiles such as water and ethanol.

Addition of Grignard derivatives to diethyl ethoxymethylene malonate generates 2-substituted diethyl malonate derivatives. This paper reports the mass spectral data for these derivatives.

We have fabricated highly efficient polymeric light-emitting diode (PLED) from water soluble non-conjugated polymer, polyurethane (PU), by using it as an ultra-thin insulating layer on the top of commercially available blue-emitting polymer, polyfluorene (PFO). The device with PU layer showed a maximum external quantum efficiency of 1.3% while the one without PU layer showed the efficiency of 0.6%. We propose that the better performance in PLED with PU layer was due to a well-balanced charge injection in emitting layer after the effective hole accumulation at the PFO/PU interface and thus increase in electron tunneling from cathode metal to emitting polymer.

Diethyl ethoxymethylenemalonate (EMME) is unexpectedly converted into diethyl 2-(1,1 -dialkyl and diarylmethyl) malonate derivatives by a classical Grignard reaction. Addition of organocuprates to EMME gave diethyl 2-(l-ethoxyalkyl) malonate derivatives. The yields range from 42-63%.

We have fabricated the polymeric light-emitting diodes (PLEDs) with new synthesized blue-emitting polymers, poly(phenyl-9,9-dioctyl-9′,9′-dihexanenitrile) fluorene (PPFC6N) and polymer blending of PPFC6N and polyfluorene (PFO). Our devices show a real blue emission for both polymers, showing the electroluminescence (EL) spectra near 445 nm, with relatively low turn-on voltage of polymer blend compared with that of PPFC6N. However, a slight blue shift occurred for PPFC6N when a 10 nm thick hole-blocking molecule, oxadiazole derivative, was introduced in the PLEDs.