The thermal chemistry of tris(2,2,6,6-tetramethyl-3,5-heptanedionato)ruthenium(III) (Ru(tmhd)3), a potential precursor for the chemical deposition of ruthenium -containing films, on Ni(110) ...single-crystal surfaces was characterized by using a combination of temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and reflection–absorption infrared spectroscopy (RAIRS). Additional characterization of the surface chemistry of the protonated ligand, Htmhd, was evaluated as well for reference. It was found that the molecularly adsorbed ruthenium compound reacts readily by approximately 310 K, loosing its ligands to both the gas phase and the surface as the central ion is reduced to its Ru0 metallic state. The diketonate ligand, now bonded to the nickel surface, starts to decompose at around 400 K, and generates gas-phase carbon monoxide and molecular hydrogen in TPD peaks at 435 K. More extensive decomposition is seen at 535 K, yielding 2,2-dimethyl-3-oxopentanal, isobutene, ketene, and carbon monoxide, and also carbon dioxide and molecular hydrogen at slightly higher temperatures. The XPS data corroborate the early reduction of the metal center and the losses of carbon- and oxygen-containing adsorbates to the gas phase, and the RAIRS traces show similar chemistry followed by the Ru complex and the free ligand, both converting via an initial decarbonylation step and a subsequent loss of the terminal tert-butyl groups. The early decomposition of the ligand on the metal surface points to potential problems with the clean deposition of metal films using diketonate complexes, but the ease with which those ligands are displaced from the central ion suggests that there is a potential for low-temperature film deposition chemistry under specific circumstances.
We investigate whether and how analytical thinking affects Muslims’ prosocial voting towards in-group (fellow Muslims) and out-group (Han Chinese) members. We conduct an incentivized laboratory-style ...voting experiment in western China, where tension and competition exist between the two ethnic groups. We find a significant negative effect of analytical thinking on prosocial voting in general. We also find that the effect of analytical thinking is related to group identity: A strong and significant negative effect is found on behavior towards out-group members, but a small and generally insignificant effect towards in-group members. Our results are consistent with group competition affecting the benefits and costs of prosocial voting, and those benefits and costs become more salient when engaging in analytical thinking.
A protocol has been developed to selectively process low-k SiCOH dielectric substrates in order to activate or deactivate them toward the deposition of thin solid films by chemical (CVD or ALD) ...means. The original SiCOH surfaces are hydrophobic, an indication that they are alkyl- rather than silanol-terminated and that, consequently, they are fairly unreactive. However, the chemical-mechanical polishing (CMP) sometimes done during microelectronics fabrication renders them hydrophilic and reactive. It was shown here that silylation of the CMP-treated surfaces with any of a number of well-known silylation agents such as HMDS, ODTS, or OTS caps the reactive silanol surface groups and turns them back to being hydrophilic and unreactive. Further exposure of any of the passivated surfaces to a combination of ozone and UV radiation reinstates their hydrophilicity and chemical activity. Importantly, it was also demonstrated that all these changes could be induced without altering the original mechanical, optical, or electrical properties of the samples: atomic force microscopy (AFM) images show no increase in roughness, ellipsometry measurements yield the same values for the index of refraction and dielectric constant, and infrared absorption spectroscopy attests to the preservation of the organic fragments present in the original SiCOH samples. The chemical selectivity of the resulting surfaces was tested for the atomic layer deposition (ALD) of HfO2 films, which could be grown only on the UV/O3 treated substrates.
Surface water bodies, such as rivers, lakes, and reservoirs, play an irreplaceable role in global ecosystems and climate systems. Sentinel-2 imagery provides new high-resolution satellite remote ...sensing data. Based on the analysis of the spectral characteristics of the Sentinel-2 satellite, a novel water index called the Sentinel-2 water index (SWI) that is based on the vegetation-sensitive red-edge band (Band 5) and shortwave infrared (Band 11) bands was developed. Four representative water body types, namely, Taihu Lake, Yangtze River, Chaka Salt Lake, and Chain Lake, were selected as study areas to conduct a water body extraction performance comparison with the normalized difference water index (NDWI). We found that (1) the contrast value of the SWI was larger than that of the NDWI in terms of various water body types, including purer water, turbid water, salt water, and floating ice, which suggested that the SWI could achieve better enhancement performance for water bodies. (2) An effective water body extraction method was proposed by integrating the SWI and Otsu algorithm, which could accurately extract various water body types with high overall accuracy. (3) The method effectively extracted large water bodies and wide river channels by suppressing shadow noise in urban areas. Our results suggested that the novel method can achieve efficient water body extraction for rapidly and accurately extracting various water bodies from Sentinel-2 data and the novel method has application potential for larger-scale surface water mapping.
The tumor necrosis factor alpha (TNF-α)–TNF-α receptor (TNFR) interaction plays a central role in the pathogenesis of various autoimmune diseases, particularly rheumatoid arthritis, and is therefore ...considered a key target for drug discovery. However, natural compounds that can specifically block the TNF-α–TNFR interaction are rarely reported. (-)-Epigallocatechin-3-gallate (EGCG) is the most active, abundant, and thoroughly investigated polyphenolic compound in green tea. However, the molecular mechanism by which EGCG ameliorates autoimmune arthritis remains to be elucidated. In the present study, we found that EGCG can directly bind to TNF-α, TNFR1, and TNFR2 with similar μM affinity and disrupt the interactions between TNF-α and TNFR1 and TNFR2, which inhibits TNF-α-induced L929 cell death, blocks TNF-α-induced NF-κB activation in 293-TNF-α response cell line, and eventually leads to inhibition of TNF-α-induced NF-κB signaling pathway in HFLS and MH7A cells. Thus, regular consumption of EGCG in green tea may represent a potential therapeutic agent for the treatment of TNF-α-associated diseases.
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•EGCG directly binds to TNF-α, TNFR1, and TNFR2 with similar μM affinity.•EGCG disrupts the interactions between TNF-α and TNFR1 and TNFR2.•EGCG inhibits TNF-α-induced L929 cell death and blocks TNF-α-induced NF-κB activation in 293-TNF-α response cell line.•EGCG inhibits TNF-α-induced NF-κB signaling pathway in HFLS and MH7A cells.•EGCG can’t inhibit LPS-induced NF-κB activation in HFLS and MH7A cells.
Path selection is one of the key technologies of wireless sensor network (WSN). A reasonable choice of coverage path can improve the service quality of WSN and extend the life cycle of WSN. ...Biogeography-based optimization (BBO) is widely used in the field of cluster intelligent optimization because its search method has a better incentive mechanism for population evolution. In this paper, the move-in and move-out operation and mutation operation of the BBO algorithm enable WSN to find an efficient routing path. In this paper, simulation experiments are carried out in two scenarios of regular deployment and random deployment of WSN nodes. The experimental results show that the quality of the WSN coverage path solution optimized by the BBO algorithm in the two scenarios is better than that of the particle swarm algorithm and genetic algorithm.
It has been established that gold, when in nanoparticle (NP) form and in contact with reducible oxides, can promote oxidation reactions under mild conditions. Here, we report results from our ...exploration of the catalytic oxidation of carbon monoxide using catalysts where Au NPs were combined with thin titanium oxide films deposited on SBA-15 using atomic layer deposition (ALD). Both orders of deposition, with TiO2 added either before or after Au dispersion, were tested for two titania film thicknesses amounting to about half and full TiO2 monolayers. The resulting catalysts were characterized using various techniques, mainly electron microscopy and N2 adsorption–desorption isotherms, and the kinetics of the oxidation of CO with O2 were followed using infrared absorption spectroscopy. A synergy between the Au and TiO2 phases as it relates to the bonding and conversion of CO was identified, the tuning of which could be controlled by varying the synthetic parameters. The ALD of TiO2 films proved to be an effective way to maximize the Au-TiO2 interface sites, and with that help with the activation of molecular oxygen.
•We look at exogenous punishments in a public goods game.•We vary the probability and the magnitude of punishment.•Large punishments with a 20% probability or small certain punishments are less ...effective.•A punishment of intermediate magnitude with a 50% probability increases cooperation.
Free riding can be made more costly by increasing either the probability of being caught or the severity of the punishment. However, neither option is without cost. What is the tradeoff between these strategies? In this study, we introduce an exogenous punishment mechanism that varies the probability and magnitude of punishment to examine this tradeoff. In our punishment system, sanctions are imposed on the lowest contributor according to a predetermined probability rather than assigned by the participants. Our results indicate that exogenous punishment enhances cooperation. Moreover, we show that a punishment of an intermediate magnitude imposed with a 50% probability is significantly more effective than a more severe punishment with a 10% probability or a lesser but certain punishment, even though the expected value of the punishment is equal across the punishment treatments.
Dendrobium
officinale
is one of the most valuable Dendrobium species and has been widely used in traditional Chinese medicine (TCM). Dendrocandins (DDCDs) are characteristic chemical structures of
D.
...officinale
and have various biological activities. Herein, we report the anticancer effects of DDCD in HepG2 cells using MTT assay. Furthermore, the mechanism of action of DDCD was determined by molecular docking and quantum chemical studies. The results showed that DDCD demonstrated significant anticancer activity against HepG2 cells by inducing apoptosis and attenuating the levels of p-AKT. Molecular modeling studies suggested the DDCD bound to the active site of AKT by the formation of four hydrogen bonds, two hydrophobic interactions, and one π-alky interaction. Quantum chemical studies were carried out on DDCD to understand the structural features essential for bioactivity. Thus, DDCD with a novel structure has the potential to be developed as an anticancer agent for liver cancer.
The evolution of the surface during the steps that comprise the atomic layer deposition (ALD) of ruthenium films on a nickel substrate using ...tris(2,2,6,6-tetramethyl-3,5-heptanedionato)ruthenium(III) (Ru(tmhd)3) and molecular oxygen was characterized using a combination of X-ray photoelectron (XPS) and reflection–absorption infrared (RAIRS) spectroscopies. The uptake of the Ru metalorganic precursor was determined to be activated, involving the average loss of two out of the three ligands (and the retention of the third, in molecular form, at the surface–vacuum interface), and self-limited, as required in ALD. The reaction of the resulting layer from that first half of the ALD cycle with O2 proved to be more complex: in addition to the desired removal of the carbon-containing material, the Ni substrate becomes oxidized, and some Ru is etched away in the form of the volatile RuO4 gas. By testing different combinations of exposures and temperatures it was determined that Ru film growth was possible, but tuning and optimizing the ALD or atomic layer etching (ALE) process conditions for maximum film growth or removal rate per cycle proved difficult. Replacing O2 with H2 was shown not to be viable either, as such an agent can reduce the nickel oxide formed after O2 treatments (in fact, Ru(tmhd)3 can do this as well) but not remove the carbonaceous material deposited on the surface by the Ru precursor. The use of N2O, on the other hand, showed much promise, being capable of removing most of the surface carbon without affecting the Ru film or the Ni substrate.
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