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Mixed dimensional van der Waals (vdW) heterostructures constructed by one-dimensional (1D) and two-dimensional (2D) materials exhibit extra degree of freedom to modulate the electronic and optical properties due to the combination of different dimensionalities. The charge transfer at the interface between 1D and 2D materials plays a crucial role in the optoelectronic properties and performance of the heterostructure-based devices. Here, we stacked single-walled carbon nanotubes (SWNTs) on monolayer WS2 for a mixed dimensional vdW heterostructure, and investigated the local modulation of excitions and trions in WS2 by SWNTs. Different directions of charge transfer between SWNTs and WS2 are evidenced by the photoluminescence (PL) spectra of WS2. The PL intensity can be either enhanced or weakened by individual SWNTs. In our work, the PL intensity of WS2 is enhanced and the exciton peak position heterostructure is red-shifted about 3 meV due to the charge transfer from WS2 to an individual SWNT (SWNT#1). The change of PL by another SWNT (SWNT#2) can not be well-resolved in far-field, but scanning near-field optical microscope (SNOM) measurements show that the PL intensity of WS2 is weakened by the SWNT. The peak position of exciton is blue-shifted by ~ 1 meV while that of trion is redshifted by ~ 1 meV due to the charge transfer from the SWNT to WS2. These results give insight into the charge transfer at the interface of SWNT/WS2 heterostructure, and can be useful for design of optoelectronic devices based on mixed dimensional vdW heterostructures.

Although nanoporous carbons are ubiquitous materials that are used in many clean energy and environmental applications, most are in powder form, thus requiring binders to hold particles together. This results in uncontrolled and complex pathways between particles, potentially exacerbating mass transport issues. To overcome these problems, we have developed an unprecedented binderless, self-supported, nanoporous carbon scaffold (NCS) with tunable and monodisperse pores (5–100+ nm), high surface area (ca. 200–575 m2 g−1), and 3-dimensional scalability (1–150+ cm2, 1–1000 μm thickness). Here, it is shown that NCS85 membranes (85 nm pores) are particularly promising as a host for the homogeneous and efficient 3-D atomic layer deposition (ALD) of Pt nanoparticles, due to the facile penetration of gas phase Pt precursor throughout the homogeneous, low tortuosity internal structure. Furthermore, the high density of surface defects of the as-synthesized NCS promotes uniform Pt nucleation with minimal agglomeration. These advantageous features are key to the rapid oxygen reduction kinetics observed under polymer electrolyte membrane (PEM) fuel cell MEA testing conditions. Cells constructed with an optimal ALD Pt loading of 30 cycles are shown to exhibit a specific activity of ≥0.4 mA cm−2Pt which is exemplary when compared to two commercial catalyst layers with comparable Pt mass loadings and tested under the same conditions. Furthermore, a maximum power density of 1230 mW cm−2 (IR-corrected) is obtained, with the limiting current densities approaching a very respectable 3 A cm−2.

We present a novel seismocardiography (SCG)-based approach for real-time cardio-respiratory activity measurement called the Autocorrelated Differential Algorithm (ADA). Measurements were performed on ten male subjects in the supine position for three 7-minute-long sets each, corresponding to 14,619 heartbeats. The ADA utilized temporal variations, windowing, and autocorrelation to produce physiological measurements corresponding to heart rate (HR), and left ventricular ejection time, and estimations of respiration rate, volume, and phase. The versatility of the ADA was investigated in two contexts: physical exertion and heart rate variability. The accuracy of HR measurements at a sampling frequency of 200 Hz resulted in a correlation coefficient ( $r^{2}$ ) of 0.9808 when compared with a manual annotation of all datasets. Its reproducibility was tested on externally obtained SCG and electrocardiography datasets, which produced an $r^{2}$ of 0.8224. The accuracy and computational time were also characterized by different sampling frequencies to quantify performance. The recommended sampling frequency is 200 Hz corresponding to a computation time of 0.05 s per instantaneous measurement using a standard desktop computer. The ADA delivered real-time SCG measurements with a refresh rate that was dependent on the computational time per measurement, which could be decreased by lowering the sampling frequency. The presented algorithm offers a novel tool toward real-time physiological monitoring in clinical and everyday scenarios.

Glucose-regulated protein 94 (Grp94), a member of the Heat shock protein 90 (Hsp90) family, is implicated in many human diseases, including cancer, neurodegeneration, inflammatory, and infectious diseases. Here, we describe our effort to design and develop a new series of Grp94 inhibitors based on Phe199 induced fit mechanism. Using an alkynyl-containing inhibitor as a starting point, we developed compound 4, which showed potent inhibitory activity toward Grp94 in a fluorescence polarization-based assay. With improved physicochemical properties and suitable pharmacokinetic properties, compound 4 was advanced into in vivo bioactivity evaluation. In a dextran sulfate sodium (DSS)-induced mouse model of ulcerative colitis (UC), compound 4 showed anti-inflammatory property and reduced the levels of pro-inflammatory cytokines (TNF-α and IL-6). Together, these findings provide evidence that this approach may be promising for further Grp94 drug development efforts.

The design and fabrication of lattice-strained platinum catalysts achieved by removing a soluble core from a platinum shell synthesized via atomic layer deposition, is reported. The remarkable catalytic performance for the oxygen reduction reaction (ORR), measured in both half-cell and full-cell configurations, is attributed to the observed lattice strain. By further optimizing the nanoparticle geometry and ionomer/carbon interactions, mass activity close to 0.8 A mgPt-1 @0.9 V iR-free is achievable in the membrane electrode assembly. Nevertheless, active catalysts with high ORR activity do not necessarily lead to high performance in the high-current-density (HCD) region. More attention shall be directed toward HCD performance for enabling high-power-density hydrogen fuel cells.

Heat shock protein (Hsp90), a critical molecular chaperone that regulates the maturation of a large number of oncogenic client proteins, plays an essential role in the growth of neoplastic cells. Herein, DDO-6600 is identified to covalent modification of Cys598 on Hsp90 from in silico study and is verified by a series of biological assays. We demonstrated that DDO-6600 covalently bound to Cys598 on the Hsp90 C terminus and exhibited antiproliferative activities against multiple tumor cells without inhibiting ATPase activity. Further studies showed that DDO-6600 disrupted the interaction between Hsp90 and Cdc37, which induced the degradation of kinase client proteins in multiple tumor cell lines, promoted apoptosis, and inhibited cell motility. Our findings offer mechanic insights into the covalent modification of Hsp90 and provide an alternative strategy for the development of Hsp90 covalent regulators or chemical probes to explore the therapeutical potential of Hsp90.

We study the nucleation stage and growth of atomic layer deposition (ALD) on hydrogen terminated silicon (Si:H) by in-situ and ex-situ scanning tunneling microscopy (STM). STM allows the in-depth study of surface chemistry and evolution during the ALD nucleation phase. Here, the ALD systems studied to demonstrate this technique are ZnO via diethyl zinc (DEZ) and TiO2 via titanium tetrachloride (TiCl4). In-situ STM revealed that DEZ does not discriminate between different surface sites, in contrast to TiCl4 which shows a strong preference towards dangling or OH bonds. Continued deposition showed distinct island growth for TiO2 deposition on Si:H, versus homogeneous growth for DEZ. ZnO ALD exhibited a delay of approximately 5 ALD cycles in transitioning from lateral to vertical growth and nominal physical film closure occurred after approximately 12-15 cycles. STM observations of these ALD chemistries demonstrated the strength of this technique in quantifying film closure and the effects of surface terminat...

The performance of oxygen reduction reaction (ORR) catalysts has been substantially improved over the past several decades. These catalysts are evaluated for electrochemical activity in a rotating disk electrode (RDE) assembly using an oxygen saturated liquid electrolyte. Koutecky-Levich (K-L) analysis provides a simple and effective method to extract electrokinetic information by correcting for mass transport effects. We propose extensions to the K-L analysis to address some of the simplifying assumptions made during its derivation. In particular, we demonstrate that decreased concentrations of surface reactants contribute to measured overpotentials in a Nernst fashion, and can lead to an underestimation of catalytic activity. By applying a Nernst overpotential correction in conjunction with K-L analysis, more accurate measurements of the intrinsic reaction kinetics under mass transport limited conditions are possible. As the K-L method assumes a reaction order of unity, we also consider kinetic reaction order deviation from unity due to measurement conditions. We show that examining the dependence of the reaction order on overpotential can provide a straightforward technique to probe blocking effects of surface absorbents. We propose that these extensions to the K-L method can allow for increased versatility of the RDE technique for extracting electrokinetic parameters for ORR catalysts.

To discover new bioactive compounds from nature plants, a primary screening of traditional Chinese medicines had been taken. The screening results showed that a EtOAc extract of Sedum sarmentosum displayed a certain degree of cytotoxic activity and bioassay-directed isolation of EtOAc extract gave two new megastigmanes, (6S,9R)-2-hydroxy-4-(2,6,6-trimethyl-4-oxo-cyclohex-2-enyl)-butyric acid (1) and (6S,9R)-2-hydroxy-4-(2,6,6-trimethyl-4-oxo-cyclohex-2-enyl)-butyric acid methyl ester (2) together with seven known flavonoids. The chemical structures of 1 and 2 were elucidated on the basis of detailed 1D, 2D NMR and MS data. When tested against HepG2 and Hep3B hepatocellular carcinoma cell lines, compounds 1–9 showed weak anti-HCC activity. In addition, in vitro antioxidant activities of 1–9 were evaluated by ABTS radical cation-scavenging assay. 1 and 2 exhibited weak activity with per micromoles equivalent to 0.039 and 0.042 μM of Trolox, respectively. The flavonoid component, quercetin (9) showed the highest antioxidant activities with per micromoles equivalent 0.67 μM of Trolox.

Cardiography is an indispensable element of health care. However, the accessibility of at-home cardiac monitoring is limited by device complexity, accuracy, and cost. We have developed a real-time algorithm for heart rate monitoring and beat detection implemented in a custom-built, affordable system. These measurements were processed from seismocardiography (SCG) and gyrocardiography (GCG) signals recorded at the sternum, with concurrent electrocardiography (ECG) used as a reference. Our system demonstrated the feasibility of non-invasive electro-mechanical cardiac monitoring on supine, stationary subjects at a cost of $100, and with the SCG&ndash, GCG and ECG algorithms decoupled as standalone measurements. Testing was performed on 25 subjects in the supine position when relaxed, and when recovering from physical exercise, to record 23,984 cardiac cycles at heart rates in the range of 36&ndash, 140 bpm. The correlation between the two measurements had r2 coefficients of 0.9783 and 0.9982 for normal (averaged) and instantaneous (beat identification) heart rates, respectively. At a sampling frequency of 250 Hz, the average computational time required was 0.088 s per measurement cycle, indicating the maximum refresh rate. A combined SCG and GCG measurement was found to improve accuracy due to fundamentally different noise rejection criteria in the mutually orthogonal signals. The speed, accuracy, and simplicity of our system validated its potential as a real-time, non-invasive, and affordable solution for outpatient cardiac monitoring in situations with negligible motion artifact.

The anion exchange membranes (AEMs) possessing a long-term alkaline stability is desired for use as the electrolyte in electrochemical devices. We prepared a series of AEMs with excellent stability and reasonable conductivity as well as acceptable mechanical properties by addition of antioxidants into quaternary ammonium modified poly(4-vinylbenzyl chloride-styrene). It is found that the synergy of hindered phenol and diphosphite antioxidants endowed the AEMs with superior resistance to the attack of both OH– ions and free radicals. The proposed membrane retained about 80% of the original conductivity after soaked in 2 M KOH aqueous solutions at 60 oC for 1300 h. The synergy effect of the dual antioxidants was investigated by Fenton tests and the fluorescence analysis. A peak power density of 526 mW cm−2 was achieved at 60 oC by the membrane-based single fuel cell fueling with humidified H2 and O2 without back pressure.

The chemical durability is a critical issue to proton exchange membranes (PEMs) for using as the electrolyte in proton exchange membrane fuel cells (PEMFCs). Herein, chemically stable membranes were prepared by grafting organic free radical scavengers (R) including 2-mercapto-1-methylimidazole (MIm), 3-mercapto-1,2,4-triazole (MTz) and 2-mercaptobenzimidazole (BIm) onto backbones of polyarylethersulfone (PAES), respectively. Having a phosphoric acid (PA) doping level of around 200 wt%, the PAES-MIm and PAES-MTz membranes exhibit, separately, anhydrous proton conductivities of 78.3 and 63.3 mS cm−1 at 180 °C, tensile stress at break of 7.8 and 9.4 MPa at room temperature, and a peak power density of 423 mW cm−2 and 358 mW cm−2 at 160 °C with a fuel cell fueling with non-humidified gases of H2 and O2. The properties of the prepared PAES-MIm and PAES-MTz membranes with and without performing the Fenton tests were all investigated on tensile stress, methanol permeability, anhydrous proton conductivity, and polarization curves of single fuel cells, respectively. The results indicate that the grafted free radical scavengers significantly enhanced the chemical stability and retarded the degradation of the PAES-R membranes. After suffered the Fenton test under harsh conditions (H2O2, 3 wt%, Fe2+, 4 ppm at 68 °C) for 60 and 100 h, a peak power density of 320 and 291 mW cm−2 is still achieved at 140 °C by the acid doped PAES-MIm membranes, respectively. Characterizations on the morphology by scanning electron microscope (SEM), and structure by Raman spectroscopy of the prepared membranes were made as well.

Four new neolignans, (E)-3-(hydroxymethyl)-2-(4-hydroxyphenyl)-5-(prop-1-en-1-yl)benzofuran-6-ol (1), methyl (E)-6-hydroxy-2-(4-hydroxyphenyl)-5-(prop-1-en-1-yl)benzofuran-3-carboxylate (2), (R)-4-hydroxy-3-(1-(4-hydroxyphenyl)propan-2-yl)benzaldehyde (3) and methyl (E,R)-3-(4-hydroxy-3-(1-(4-hydroxyphenyl)propan-2-yl)phenyl)acrylate (4) were isolated from the seeds of Daphniphyllum macropodum Miq, together with four known compounds. The structures of the new compounds were established by spectroscopic analyses, including 1D and 2D NMR as well as HRESIMS data. The absolute configurations of 3 and 4 were determined by the comparison of experimental and calculated electronic circular dichroism (ECD) spectra. All the compounds were evaluated for their antiproliferative activity on human NSCLC A549 and H460 cell lines. Compound 2 significantly inhibited the cancer cell growth in a dose-dependent manner. Mechanism of the action studies showed that 2 increased the expression of bax, caspase-3 and caspase-9, and decreased the production of bcl-2, suggesting that 2 induced apoptosis in A549 cells through activating the mitochondrial pathway.

Tuning nanoparticle strain The catalytic activity of metals in heterogeneous catalysts can be altered by applying strain, which changes the crystalline lattice spacing and modifies the metal's electronic properties. Wang et al. show how particles of cobalt oxide, a positive electrode for lithium batteries, can expand or contract with charging and transfer strain to adsorbed platinum nanoparticles. For the oxygen reduction reaction used in fuel cells, compressive strain boosted activity by 90%, and tensile strain decreased it by 40%. Science , this issue p. 1031

A suitable microphase separation morphology has been demonstrated to be an efficient strategy to achieve high ionic conductivity with reasonable durability to anion exchange membranes (AEMs). Herein, hydrophilic oligomers of polyethylene glycols (PEGs) with different molecular weights were blended, separately, with poly(2,6-dimethyl-1,4-phenylene oxide) modified by 4,4-diethoxybutan-1-amine and 1-methylpiperidine (20PDM). The presence of hydrophilic PEGs facilitates the formation of the interconnected nano-channels in the AEMs for ion conduction according to the analysis results by both transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The membrane containing 2 wt% PEGs with a molecular weight of 2 kDa reaches a hydroxide conductivity of 97.2 mS cm−1 at 80 °C, which is 25 mS cm−1 higher than that the pristine 20PDM membrane possessing the same ion exchange capacity. A peak power density of 328 mW cm−2 is attained at 60 °C by the proposed membrane based single fuel cell fueling with humidified H2 and O2 with 0.1 MPa of back pressure. The chemical structure, water uptake and swelling as well as resistance to hot alkali solutions of the prepared membranes were investigated.

The title compound, 7β-hy­droxy­royleanone, an abietane-type diterpene, was isolated from Taxodium ascendens (B.)., The title compound, C20H28O4 [systematic name: (4bS,8aS,10S)-3,10-dihy­droxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octa­hydro­phenanthrene-1,4-dione], is an abietane-type diterpene, which was isolated from Taxodium ascendens (B.). The compound crystallizes in the chiral space group P21, but it was not possible to determine the absolute structure of the mol­ecule in the crystal by resonant scattering. The mol­ecular structure is stabilized by two intra­molecular O—H⋯O hydrogen bonds, enclosing S(5) and S(6) ring motifs. In the crystal, mol­ecules are linked by O—H⋯O and C—H⋯O hydrogen bonds, forming chains along the [010] direction. The crystal structure of the 10R stereoisomer of the title compound, isolated from the roots of Premna obtusifolia (Verbenaceae), has been reported. It crystallized in the chiral space group P212121, and the absolute structure was determined as (4bS,8aS,10R), by resonant scattering using Cu Kα radiation [Razak et al. (2010 ▸). Acta Cryst. E66, o1566–o1567].

The title compound [systematic name: (4bS)-4-hydroxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a-hexahydrophenanthrene-3,9-dione], C20H26O3, is an abietane-type diterpene, which was isolated fromTaxodium ascendens(B.). In the crystal, molecules are linked by weak C—H...O hydrogen bonds, forming supramolecular chains propagating along the [001] direction.