Full-Color Circularly Polarized Luminescence of Supramolecular Polymers with Handedness Inversion Regulated by Anion and Temperature.

Constructing full-color circularly polarized luminescence (CPL) materials with switchable handedness in the solid state is an appealing yet considerably challenging task, especially for supramolecular polymer films assembled from homochiral monomers. Herein, supramolecular polymers with full-color CPL and inverted handedness are realized through the coassembly of a homochiral cholesterol derivative (PVPCC), metal ions (Zn2+), and achiral fluorescent dyes. The obtained coassembled systems show anion-directed supramolecular chirality inversion by exchanging the anions of NO3-, ClO4-, BF4-, and Cl-. For instance, the negative CD and right-handed CPL are detected in the PVPCC/Zn(NO3)2 aggregates, which convert into positive CD and left-handed CPL after introducing Cl-, corresponding to the transformation from nanorods to nanofibers. Furthermore, the tunable CPL color and handedness inversion of the coassembly system of PVPCC/Zn(NO3)2 and achiral fluorescent dyes can be established by alternately changing the assembling temperature of 298 and 273 K. Importantly, the full-color CPL polymeric materials are then constructed by doping the PVPCC/Zn(NO3)2/dyes complexes into poly(methyl methacrylate) (PMMA) film, which maintains the handedness inversion and shows the enhanced CPL performance. The work not only deepens the understanding of chirality inversion in supramolecular chemistry but also helps to construct full-color CPL materials with switchable handedness from homochiral building blocks in materials science.

Multicolor circularly polarized luminescence inversion of metal-organic supramolecular polymers.

Metal-organic supramolecular polymers (MOSPs) with multicolor circularly polarized luminescence (CPL) and handedness inversion were constructed from the coordination-driven assembly of pyridine-cyanostilbene-cholesterol and metal salts by modulating the treatment modes, solvents, and metal ions.

Engineering Fe-N4 Electronic Structure with Adjacent Co-N2C2 and Co Nanoclusters on Carbon Nanotubes for Efficient Oxygen Electrocatalysis.

Regulating the local configuration of atomically dispersed transition-metal atom catalysts is the key to oxygen electrocatalysis performance enhancement. Unlike the previously reported single-atom or dual-atom configurations, we designed a new type of binary-atom catalyst, through engineering Fe-N4 electronic structure with adjacent Co-N2C2 and nitrogen-coordinated Co nanoclusters, as oxygen electrocatalysts. The resultant optimized electronic structure of the Fe-N4 active center favors the binding capability of intermediates and enhances oxygen reduction reaction (ORR) activity in both alkaline and acid conditions. In addition, anchoring M-N-C atomic sites on highly graphitized carbon supports guarantees of efficient charge- and mass-transports, and escorts the high bifunctional catalytic activity of the entire catalyst. Further, through the combination of electrochemical studies and in-situ X-ray absorption spectroscopy analyses, the ORR degradation mechanisms under highly oxidative conditions during oxygen evolution reaction processes were revealed. This work developed a new binary-atom catalyst and systematically investigates the effect of highly oxidative environments on ORR electrochemical behavior. It demonstrates the strategy for facilitating oxygen electrocatalytic activity and stability of the atomically dispersed M-N-C catalysts.

Solvent-Directed Hierarchical Self-Assembly of Tetraphenylpyrazine-Cholesterol with Amplified Circularly Polarized Luminescence.

It is important to identify the effect of assembly and aggregation on the chirality transfer and energy transmission in supramolecular polymer system, since the unordered aggregation is insufficient to promote luminescence enhancement and chirality transfer, even causing the negative effect. Another key issue is to identify the solvent effect on hierarchically chiral self-assembly. Herein, we designed an AIE-core based building block, tetraphenylpyrazine-cholesterol (TPP-Chol), to explore how the solvent component influences chirality transfer and energy transmission of its aggregates and/or assemblies. Interestingly, the hierarchical assembly behavior was realized in the mixture of MeOH/CHCl3 highly dependent on the MeOH content. During the solvent-directed hierarchical assembly, the morphologic transformations, such as nanoribbons with a width of 150 nm, twisted nanoribbons with helical pitch of 420 nm, nanoribbon clusters, and microflowers with an average diameter of 5.5 µm, were realized with obvious chirality amplification for both circular dichroism (CD) and circularly polarized luminescence (CPL) measurements. The hierarchical assembly of TPP-Chol was also demonstrated by a time-dependent CD test. The work points out the complexity and dynamic of hierarchically chiral self-assembly regulated by the solvent effect, which would be helpful for the development of supramolecular materials with enhanced CPL performance and dynamic chirality.

Metallophilic Interaction-Mediated Hierarchical Assembly and Temporal-Controlled Dynamic Chirality Inversion of Metal-Organic Supramolecular Polymers.

The study of dynamic supramolecular chirality inversion (SMCI) not only helps to deepen the understanding of chiral transfer and amplification in both living organizations and artificially chemical self-assembly systems but also is useful for the development of smart chiral nanomaterials. However, it is still challenging to achieve the dynamic SMCI of the self-aggregation of metal-organic supramolecular polymers with great potential in asymmetric synthesis, chiroptical switches, and circular polarized luminescence. Here, we successfully developed a hierarchical coassembly system based on the mPAzPCC and various metal ions with effective chirality transfer and temporal-controlled SMCI. Due to the dynamic self-assembly and hierarchical chirality transfer of the Ag+/mPAzPCC complex driven by metallophilic interaction and coordination, morphological transition with nanoribbons, helical nanoribbons, and chiral nanotubules was successively obtained. Interestingly, the SMCI of chiral nanoaggregates was precisely regulated by solvents and metal ions in the Cu2+/mPAzPCC and Mn2+/mPAzPCC system. Besides, temporal-controlled dynamic SMCI switching from helix to bundled helix was clearly revealed in the aggregation of Cu2+/mPAzPCC, Mn2+/mPAzPCC, and Bi3+/mPAzPCC systems. This work provides a metallophilic interaction-mediated helical assembly pathway to dynamically modulate the chirality of metal-organic complex-based assemblies and deepen the understanding of the hierarchically dynamic self-assembly process, which would be of great potential in metal ion-mediated supramolecular asymmetric catalysis and bioinspired chiral sensing.

Boosting Oxygen-Evolving Activity via Atom-Stepped Interfaces Architected with Kinetic Frustration.

A highly active interface is extremely critical for the catalytic efficiency of an electrocatalyst; however, facilely tailoring its atomic packing characteristics remains challenging. Herein, a simple yet effective strategy is reported to obtain copious high-energy atomic steps at the interface via controlling the solidification behavior of glass-forming metallic liquids. By adjusting the chemical composition and cooling rate, highly faceted FeNi3 nanocrystals are in situ formed in an FeNiB metallic glass (MG) matrix, leading to the creation of order/disorder interfaces. Benefiting from the catalytically active and stable atomic steps at the jagged interfaces, the resultant free-standing FeNi3 nanocrystal/MG composite exhibits a low oxygen-evolving overpotential of 214 mV at 10 mA cm-2 , a small Tafel slope of 32.4 mV dec-1 , and good stability in alkaline media, outperforming most state-of-the-art catalysts. This approach is based on the manipulation of nucleation and crystal growth of the solid-solution nanophases (e.g., FeNi3 ) in glass-forming liquids, so that the highly stepped interface architecture can be obtained due to the kinetic frustration effect in MGs upon undercooling. It is envisaged that the atomic-level stepped interface engineering via the physical metallurgy method can be easily extended to other MG systems, providing a new and generic paradigm for designing efficient yet cost-effective electrocatalysts.

Multiple chirality inversion of pyridine Schiff-base cholesterol-based metal-organic supramolecular polymers.

Based on a metal coordination driven co-assembly strategy, a metal-organic supramolecular polymer system of pyridine Schiff-base cholesterol and metal ions with multiple supramolecular chirality inversion was successfully achieved by the stoichiometry and exchange of metal ions (such as Co2+, Ni2+, Cu2+, Zn2+, and Ag+), as well as the solvent polarity.

Design of a Robust Tool for Deploying Large-Area Stretchable Sensor Networks from Microscale to Macroscale.

An investigation was conducted to develop an effective automated tool to deploy micro-fabricated stretchable networks of distributed sensors onto the surface of large structures at macroscale to create "smart" structures with embedded distributed sensor networks. Integrating a large network of distributed sensors with structures has been a major challenge in the design of so-called smart structures or devices for cyber-physical applications where a large amount of usage data from structures or devices can be generated for artificial intelligence applications. Indeed, many "island-and-serpentine"-type distributed sensor networks, while promising, remain difficult to deploy. This study aims to enable such networks to be deployed in a safe, automated, and efficient way. To this end, a scissor-hinge controlled system was proposed as the basis for a deployment mechanism for such stretchable sensor networks (SSNs). A model based on a kinematic scissor-hinge mechanism was developed to simulate and design the proposed system to automatically stretch a micro-scaled square network with uniformly distributed sensor nodes. A prototype of an automatic scissor-hinge stretchable tool was constructed during the study with an array of four scissor-hinge mechanisms, each belt-driven by a single stepper motor. Two micro-fabricated SSNs from a 100 mm wafer were fabricated at the Stanford Nanofabrication Facility for this deployment study. The networks were designed to be able to cover an area 100 times their manufacturing size (from a 100 mm diameter wafer to a 1 m2 active area) once stretched. It was demonstrated that the proposed deployment tool could place sensor nodes in prescribed locations efficiently within a drastically shorter time than in current labor-intensive manual deployment methods.

Structure and Anti-Inflammatory Activity Relationship of Ergostanes and Lanostanes in Antrodia cinnamomea.

Antrodia cinnamomea is a precious edible mushroom originating from Taiwan that has been popularly used for adjuvant hepatoprotection and anti-inflammation; however, the chemical principle for its anti-inflammatory activity has not been elucidated, which prevents the quality control of related products. Using the RAW264.7 model for the anti-inflammatory activity assay as a guide, we reported the isolation and structural elucidation of three potent anti-inflammatory compounds from isolated ergostanes (16) and lanostanes (6). Their structures were elucidated on the basis of spectroscopic data analysis including NMR and HR-QTOF-MS. Particularly, the absolute configurations of (25R)-antcin K, (25R)-antcin A, versisponic acid D, and (25R)-antcin C were determined by single crystal X-ray diffraction (XRD). The representative and most promising compound antcin A was shown to suppress pro-inflammatory biomolecule release via the down-regulation of iNOS and COX-2 expression through the NF-κB pathway while the mRNA levels of IL-1ß, TNF-α and IL-6 were also decreased. The high dependency on structural variation and activity suggests that there might be special biological targets for antcin A. Our work makes it possible to develop evidence-based dietary supplements from Antrodia cinnamomea based on anti-inflammatory constituents.

Association between medication adherence and disease outcomes in patients with hepatitis B-related cirrhosis: a population-based case-control study.

OBJECTIVE: To evaluate medication adherence among patients with hepatitis B-related cirrhosis who developed decompensation and mortality, and to examine the association between medication adherence and patients' disease outcomes. DESIGN: In this retrospective case-control study, patients aged over 20 years old and diagnosed with both chronic hepatitis B and cirrhosis from 2007 to 2016 are identified using a population-based medical claims database. Two prognosis endpoints (decompensation and mortality) are used, respectively, to classify subjects into two different case-control sets. Study groups are propensity-score matched. Medication possession ratio (MPR) is used as a measure of treatment adherence for oral antiviral drugs, and conditional logistic regression models are used to estimate the odds of decompensation and mortality after accounting for MPR and other covariates. RESULTS: Between decompensated and compensated patients, longer term treatment adherence is seen higher in the compensated group versus the decompensated group: 1-year MPR (0.65±0.43 vs 0.57±0.53) and 6-month MPR (0.79±0.52 vs 0.76±0.79). On the contrary, 3-month adherence is higher in the decompensated group (1.00±1.15 vs 0.96±0.79). For patients with and without mortality, drug adherence is ubiquitously higher in the alive group regardless of follow-up length: 1-year MPR (0.62±0.44 vs 0.50±0.51), 6-month MPR (0.78±0.62 vs 0.69±0.72) and 3-month MPR (0.97±0.91 vs 0.96±1.12). After accounting for confounding variables, we find that the likelihood of complicated cirrhosis is significantly lower in more adherent patients and the benefit increases with more persistent adherence (log 1-year MPR OR: 0.75, 95% CI: 0.73 to 0.77). Similar results are observed for the adjusted likelihood of mortality (log 1-year MPR OR: 0.70, 95% CI: 0.68 to 0.72). CONCLUSIONS: Long-term patient adherence to oral antiviral therapy remains inadequate in patients with hepatitis B virus-related cirrhosis. Their adherence to oral antiviral therapy appears to be inversely associated with decompensation and mortality.

High-content atomically distributed W(V,VI) on FeCo layered double hydroxide with high oxygen evolution reaction activity.

High-content atomically distributed W(V,VI) coordinated with O atoms as WO2 moieties anchored on FeCo layered double hydroxide (FeCo LDH) nanosheets in the structure of SAC W-FeCo LDH is obtained by a facile coprecipitation method, and it presented clearly enhanced stable OER electrocatalytic activity.

Self-supported efficient hydrogen evolution catalysts with a core-shell structure designed via phase separation.

The development of cost-effective, high-performance and flexible electrocatalysts for hydrogen production is of scientific and technological importance. Catalysts with a core-shell structure for water dissociation have been extensively investigated. However, most of them are nanoparticles and thus their catalytic properties are inevitably limited by the use of binders in practice. Herein, this work reports a physical-metallurgy-based structural design strategy to develop a self-supported and unique nanoporous structure with core-shell-like ligaments, i.e., a Cu core surrounded by a NiO shell, formed on a metallic glass (MG) substrate. These newly developed noble metal-free catalysts exhibit outstanding HER performance; the overpotential reaches 67 mV at a current density of 10 mA cm-2, accompanied by a low Tafel slope of 40 mV dec-1 and good durability. More importantly, the current strategy could be readily applied to fabricate other nanoporous metals, which opens a new space for designing advanced catalysts as cost-effective electrode materials.

Quantitative Förster Resonance Energy Transfer: Efficient Light Harvesting for Sequential Photo-Thermo-Electric Conversion.

Light is essential to all life on the earth. Thus, highly efficient light-harvesting systems with the sequential energy transfer process are significant for using solar energy in photosynthesis. For developing an efficient light-harvesting system, a liquid aggregation-induced emission (AIE) dye TPE-EA is obtained, as a donor and solvent, which can light up the aggregation caused quenching (ACQ) Nile Red (NiR, acceptor) to construct a quantitative Förster resonance energy transfer (FRET) system in NiR⊂TPE-EA. Impressively, this FRET pair shows an impressive photothermal effect, producing a peak temperature of 119 °C while excited by UV light, with 37.8% of conversion efficiency. NiR⊂TPE-EA is quite different from most other photothermal materials, which require excitation with long wavelength light (>520 nm). Therefore, NiR⊂TPE-EA firstly converts the solar into thermal energy and then into electric energy to achieve sequential photo-thermo-electric conversion. Such sequential conversion, suitable for being excited by sunlight, is anticipated to unlock new and smart approaches for capturing solar energy.

Cooperatively assembled liquid crystals enable temperature-controlled Förster resonance energy transfer.

Balancing the rigidity of a π-conjugated structure for strong emission and the flexibility of liquid crystals for self-assembly is the key to realizing highly emissive liquid crystals (HELCs). Here we show that (1) integrating organization-induced emission into dual molecular cooperatively-assembled liquid crystals, (2) amplifying mesogens, and (3) elongating the spacer linking the emitter and the mesogen create advanced materials with desired thermal-optical properties. Impressively, assembling the fluorescent acceptor Nile red into its host donor designed according to the aforementioned strategies results in a temperature-controlled Förster resonance energy transfer (FRET) system. Indeed, FRET exhibits strong S-curve dependence as temperature sweeps through the liquid crystal phase transformation. Such thermochromic materials, suitable for dynamic thermo-optical sensing and modulation, are anticipated to unlock new and smart approaches for controlling and directing light in stimuli-responsive devices.

Amplifying the excited state chirality through self-assembly and subsequent enhancement via plasmonic silver nanowires.

The development of circularly polarized luminescent materials with a large luminescence dissymmetry factor (glum) is continuing to be a big challenge. Here, we present a general approach for amplifying circular polarization of circularly polarized luminescence (CPL) through intergrating molecular self-assembly and surface plasmon resonance (SPR). Molecular self-assembly could amplify the CPL performance. Subsequently, the composites built of nanoassemblies and achiral silver nanowires (AgNWs) show intense CPL activity with an amplified glum value. By applying an external magnetic field, the CPL activity of the nanoassemblies/AgNWs composites has been significantly enhanced, confirming a plasmon-enhanced circular polarization. Our design strategy based on SPR-enhanced circular polarization of the chiral emissive systems suggests that combining plasmonic nanomaterials with chiral organic materials could aid in the development of novel CPL active nanomaterials.

Design and Integration of a Wireless Stretchable Multimodal Sensor Network in a Composite Wing.

This article presents the development of a stretchable sensor network with high signal-to-noise ratio and measurement accuracy for real-time distributed sensing and remote monitoring. The described sensor network was designed as an island-and-serpentine type network comprising a grid of sensor "islands" connected by interconnecting "serpentines." A novel high-yield manufacturing process was developed to fabricate networks on recyclable 4-inch wafers at a low cost. The resulting stretched sensor network has 17 distributed and functionalized sensing nodes with low tolerance and high resolution. The sensor network includes Piezoelectric (PZT), Strain Gauge (SG), and Resistive Temperature Detector (RTD) sensors. The design and development of a flexible frame with signal conditioning, data acquisition, and wireless data transmission electronics for the stretchable sensor network are also presented. The primary purpose of the frame subsystem is to convert sensor signals into meaningful data, which are displayed in real-time for an end-user to view and analyze. The challenges and demonstrated successes in developing this new system are demonstrated, including (a) developing separate signal conditioning circuitry and components for all three sensor types (b) enabling simultaneous sampling for PZT sensors for impact detection and (c) configuration of firmware/software for correct system operation. The network was expanded with an in-house developed automated stretch machine to expand it to cover the desired area. The released and stretched network was laminated into an aerospace composite wing with edge-mount electronics for signal conditioning, processing, power, and wireless communication.

Static Tactile Sensing for a Robotic Electronic Skin via an Electromechanical Impedance-Based Approach.

Tactile sensing is paramount for robots operating in human-centered environments to help in understanding interaction with objects. To enable robots to have sophisticated tactile sensing capability, researchers have developed different kinds of electronic skins for robotic hands and arms in order to realize the 'sense of touch'. Recently, Stanford Structures and Composites Laboratory developed a robotic electronic skin based on a network of multi-modal micro-sensors. This skin was able to identify temperature profiles and detect arm strikes through embedded sensors. However, sensing for the static pressure load is yet to be investigated. In this work, an electromechanical impedance-based method is proposed to investigate the response of piezoelectric sensors under static normal pressure loads. The smart skin sample was firstly fabricated by embedding a piezoelectric sensor into the soft silicone. Then, a series of static pressure tests to the skin were conducted. Test results showed that the first peak of the real part impedance signal was sensitive to static pressure load, and by using the proposed diagnostic method, this test setup could detect a resolution of 0.5 N force. Numerical simulation methods were then performed to validate the experimental results. The results of the numerical simulation prove the validity of the experiments, as well as the robustness of the proposed method in detecting static pressure loads using the smart skin.

PGM-Free Fe/N/C and Ultralow Loading Pt/C Hybrid Cathode Catalysts with Enhanced Stability and Activity in PEM Fuel Cells.

In this work, the stability behaviors of the state-of-the-art Fe/N/C and Pt/C catalysts (as well as the activation time of the latter) were first systematically investigated, under different cathode catalyst loadings, in the membrane electrode assemblies (MEA) in PEM fuel cells. Based on that, two types of cathode electrodes with the combination of Fe/N/C and Pt/C catalysts were developed (type I: layered hybrid catalysts with Pt/C next to the membrane and type II: uniformly mixed catalysts). In this way, the shortcomings of the Fe/N/C catalyst (the fast decay) and the Pt/C catalyst (the long activation time) can be compensated at the same time. The hybrid catalysts also showed a very short activation time (a few hours vs over 10 h for Pt/C with the same Pt loading). Comparing the two types of hybrid catalysts, type I shows a much higher current density. The loadings of the Fe/N/C and Pt/C catalysts in the hybrid electrode were systematically studied, with optimal values of 1.0 mg cm-2 for Fe/N/C and 0.035 mgPt cm-2 for Pt/C. The Pt loading of this hybrid catalyst (type I) at the cathode only takes ca. 30% of the U.S. Department of Energy (DOE) target of Pt usage (0.100 mgPt cm-2), while its mass activity of Pt (in H2/O2 PEMFC) is 0.22 A mgPt-1 at 0.9iR-free V, reaching half of the DOE activity target (0.44 A mgPt-1), which is among the best performances reported so far. Via both half-cell and single-cell electrochemical evaluations together with other characterizations, the origin of the improved activity and stability is believed to be the synergistic effect between Pt/C and Fe/N/C catalysts to ORR. This work provides an effective strategy for engineering highly performing MEA for the industrialization of PEM fuel cells.

Discovery of T-1101 tosylate as a first-in-class clinical candidate for Hec1/Nek2 inhibition in cancer therapy.

Highly expressed in cancer 1 (Hec1) plays an essential role in mitosis and is correlated with cancer formation, progression, and survival. Phosphorylation of Hec1 by Nek2 kinase is essential for its mitotic function, thus any disruption of Hec1/Nek2 protein-protein interaction has potential for cancer therapy. We have developed T-1101 tosylate (9j tosylate, 9j formerly known as TAI-95), optimized from 4-aryl-N-pyridinylcarbonyl-2-aminothiazole of scaffold 9 by introducing various C-4' substituents to enhance potency and water solubility, as a first-in-class oral clinical candidate for Hec1 inhibition with potential for cancer therapy. T-1101 has good oral absorption, along with potent in vitro antiproliferative activity (IC50: 14.8-21.5 nM). It can achieve high concentrations in Huh-7 and MDA-MB-231 tumor tissues, and showed promise in antitumor activity in mice bearing human tumor xenografts of liver cancer (Huh-7), as well as of breast cancer (BT474, MDA-MB-231, and MCF7) with oral administration. Oral co-administration of T-1101 halved the dose of sorafenib (25 mg/kg to 12.5 mg/kg) required to exhibit comparable in vivo activity towards Huh-7 xenografts. Cellular events resulting from Hec1/Nek2 inhibition with T-1101 treatment include Nek2 degradation, chromosomal misalignment, and apoptotic cell death. A combination of T-1101 with either of doxorubicin, paclitaxel, and topotecan in select cancer cells also resulted in synergistic effects. Inactivity of T-1101 on non-cancerous cells, a panel of kinases, and hERG demonstrates cancer specificity, target specificity, and cardiac safety, respectively. Subsequent salt screening showed that T-1101 tosylate has good oral AUC (62.5 µM·h), bioavailability (F = 77.4%), and thermal stability. T-1101 tosylate is currently in phase I clinical trials as an orally administered drug for cancer therapy.

Corrosion Engineering To Synthesize Ultrasmall and Monodisperse Alloy Nanoparticles Stabilized in Ultrathin Cobalt (Oxy)hydroxide for Enhanced Electrocatalysis.

Two-dimensional (2D) nanomaterials decorated with ultrasmall and well-alloyed bimetallic nanoparticles (NPs) have many important applications. Developing a facile and scalable 2D material/hybrid synthesis strategy is still a big challenge. Herein, a top-down corrosion strategy is developed to prepare ultrathin cobalt (oxy)hydroxide nanosheets decorated with ultrasmall (∼1.6 nm) alloy NPs. The formation of ultrathin (oxy)hydroxide nanosheets has a restrain effect to prevent the growth of small NPs into bigger ones. Thanks to the ultrathin 2D nature and strong electronic interaction between Co(OH)2 and alloy NPs, the Pt-based binary alloy NPs are greatly stabilized by the Co(OH)2 nanosheets and the hybrids exhibit much enhanced electrocatalytic performance for water splitting. Especially, the mass activities of the PtPd- and PtCu-decorated samples for hydrogen evolution are ∼8 times that of Pt/C. When used as both cathode and anode electrocatalysts to split water, the hybrid nanosheets outperform the commercial Pt/C-RuO2 combination. At 10 mA cm-2, the needed potential is only 1.53 V. This work provides us a highly controllable and scalable means to produce clean 2D nanomaterials decorated with a series of alloy NPs such as PtPd, PtCu, AuNi, and so forth.