Ionic liquids (ILs) modification, following the concept of “solid catalyst with ionic liquid layer (SCILL)”, has been demonstrated to be an effective approach to improving both activity and stability ...of Pt-based catalysts for the oxygen reduction reaction. In this work, the SCILL concept has been applied to a trimetallic PtNiMo/C system, which has been documented recently to be significantly advantageous over the benchmark PtNi-based catalysts for oxygen reduction. To achieve this, two hydrophobic ILs (BMIMNTF2 and MTBDBETI) were used to modify PtNiMo/C with four IL-loading amounts between 7 and 38 wt %. We found that the Pt mass activity (@0.9 V) could be improved by up to 50% with BMIMNTF2 and even 70% when MTBDBETI is used. Exceeding a specific IL loading amount, however, leads to a mass transport related activity drop. Moreover, it is also disclosed that both ILs can effectively suppress the formation of nonreactive oxygenated species, while at the same time imposing little effect on the electrochemical active surface area. For a deeper understanding of the degradation mechanism of pristine and IL modified PtNiMo/C, we applied identical location transmission electron microscopy and in situ scanning flow cell coupled to inductively coupled plasma mass spectrometry techniques. It is disclosed that the presence of ILs has selectively accelerated the dissolution of Mo and eventually results in a more severe degradation of PtNiMo/C. This shows that future research needs to identify ILs that prevent the Mo dissolution to leverage the potential of the IL modification of PtNiMo catalysts.
Designed manipulation of the morphology of metallic nanostructures containing Pd and/or Pt represents a challenge in the search of highly efficient precious metal catalysts. We provide herein the ...first selective synthesis of narrowly sized small (21 nm) Au@Pd concave nanocubes enclosed with high-index Pd facets by deposition of Pd atoms on truncated-octahedral Au seeds. Moreover, further controlled deposition of Pt onto these Au@Pd concave nanocubes produces sub-30 nm trimetallic Pt-on-(Au@Pd) nanostructures having jagged Pt-rich surfaces. The as-prepared Au@Pd and Pt-on-(Au@Pd) nanostructures are found highly active and fairly stable when employed as anode catalysts for ethanol electrooxidation, their activity normalized to the mass of Pd or Pd plus Pt being 7–9 times higher than conventional Pd black catalyst. These data may echo the importance of innovative small multimetallic nanostructures for highly efficient catalysts that depend critically on use of precious metals, for applications in energy, environmental, and chemical technologies.
Toll-like receptors (TLRs) are important components of pattern recognition receptors (PRRs), which play significant roles in innate immunity to defense against pathogen invasion. Many TLRs have been ...found in teleosts, but there are no reports about cloning and expression of TLR genes in yellow catfish (Pelteobagrus fulvidraco). In this study, we analyzed the sequence characters and the relative mRNA expression levels of nine TLRs (TLR1, TLR2, TLR3, TLR4-1, TLR5, TLR7, TLR8-2, TLR9 and TLR22) in different tissues of yellow catfish. The results showed that all nine TLR genes are highly expressed in head kidney, trunk kidney, spleen and liver, all of which are related to host immunity. Subsequently we used Aeromonas hydrophila as a stimulating agent to detect the expression profiles of these nine TLRs in the liver, spleen, trunk kidney and head kidney of yellow catfish at different time points after injection with killed Aeromonas hydrophila. All nine TLRs responded to A. hydrophila challenge with tissue-specific patterns in different immune tissues. The kinetics of up- or down-regulation of these nine TLRs exhibited a similar trend, rising to an elevated level at first and then falling to the basal level, but the peak value differed at different time points in different tissues. The expression levels of the TLR3, TLR4-1, TLR9 and TLR22 genes were significantly up-regulated after bacterial challenge in the liver, spleen, head kidney and trunk kidney. The relatively high expression of TLR genes in the immune tissues in response to the A. hydrophila challenge indicated that TLRs may play important roles in the innate immune response against gram-negative bacteria in yellow catfish.
•Nine TLR genes were identified in yellow catfish.•Deduced amino acid sequences of nine TLRs were analyzed.•All the Nine TLRs were mainly expressed in the liver, spleen, head kidney and trunk kidney.•All the Nine TLRs responded to A. hydrophila challenge with different expression patterns in immune-related tissues.
Cisplatin (CDDP) is of importance in cancer treatment and widely used in advanced gastric cancer (GC). However, its clinical usage is limited due to its resistance, and the regulatory mechanism of ...CDDP resistance in GC has not yet been fully elucidated. In this study, we first conducted a comprehensive study to investigate the role of MFAP2 through bioinformatics analysis.
The Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases were applied to downloadgene expression data and clinicopathologic data, and the differentially expressed genes (DEGs) were further analyzed. Then, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and survival analysis were conducted. Furthermore, according to the clinicopathological characteristics of TCGA, clinical correlation analysis was conducted, and a receiver operating characteristic curve (ROC) was plotted.
We revealed that
,
and
were good diagnostic factors of GC. However, the mechanism of MFAP2 in GC remains elusive, especially in the aspect of chemotherapy resistance. We developed the CDDP-resistant cell line, and found that MFAP2 was upregulated in CDDP-resistant cells, and MFAP2-knockdown improved CDDP sensitivity. Finally, we found that MFAP2 enhanced CDDP resistance by inducing autophagy in drug-resistant cell lines.
The above results suggested that MFAP2 could affect the chemotherapy resistance by altering the level of autophagy in GC patients as a potential therapeutic target.
This study investigates the importance of preconditioning in Pt‐alloy catalysts for oxygen–reduction reactions. Previous research indicated that slower scanning rates during preconditioning initially ...boost activity, but this is followed by a rapid decline. The study reveals the required number of cycles to achieve the first constant steady state activity in PtNiMo/C catalysts when using slower scanning rates during preconditioning. It also highlights the resulting activity differences. Remarkably, a catalyst preconditioned with 150 slow cycles showed an activity of approximately 1.25 mA cm−2 at 0.90 VRHE, significantly higher than one preconditioned at a fast rate (0.82 mA cm−2). Both ex–situ and in–situ analyses revealed that Pt, along with Ni, was leached during pretreatment. At slower scan rates of 20 mV s−1, the dissolved Pt redeposited as highly active, small‐sized clusters or single atoms. Fast scan rates of of 500 mV s−1, in contrast, resulted in fewer such clusters. Accelerated stress tests up to 1.10 VRHE confirmed the high stability of these clusters, demonstrating a substantial activity increase even after 24,000 cycles.
Chances in the preconditioning of Pt alloy catalysts have a huge impact to the specific activity outcome. A slow pretreatment at 20 mV s−1 results in a fast increase, strong drop and reaching nearly steady state activities at high cycle numbers. Alongside a change in the octahedral PtNiMo/C catalyst to Pt clusters is observed.
Pt‐based alloy catalysts supported on carbon are commonly characterized for oxygen reduction reaction (ORR) activity using the rotating disk electrode technique (RDE). Within this study, we show ...exemplarily for PtNiMo/C catalysts that the applied pretreatment influences strongly the determined activity. The classically employed descriptor of unchanged cyclic voltammetry response is insufficient to portrait completed surface restructuring, and gives an incorrect impression that stable activity can be determined. This might be one of the reasons for the strongly deviating activities reported in literature. Following the changes in activity during pretreatment also with in‐situ FTIR and online dissolution measurements gives insights to an up to now largely overseen high activity of the trimetallic catalysts. A maximum activity of 0.57 mA cmPt−2 at 0.95 VRHE is reached quickly during the first six cycles and decreases slowly subsequently. The maximum activity and change of activity over the cycle number is affected by the scan rate and electrolyte refreshing, while the gas atmosphere plays only a minor role. This exemplary study might be important for Pt alloy catalysts in general.
An up to now unknown activity development is achieved during the pretreatment of alloyed trimetallic PtNiMo/C catalysts. In addition to the recording of steady state CVs under electrochemical cleaning cycles, insight into the unconditioned specific activity of the catalyst reveals a sharp increase during the first five to eight cycles and a further decrease at higher cycle numbers.
The yellow catfish (
) is an economic fish with a large breeding scale, and diseases have led to huge economic losses. Tumor necrosis factor receptor-associated factors (TRAFs) are a class of ...intracellular signal transduction proteins that play an important role in innate and adaptive immune responses by mediating NF-κB, JNK and MAPK signaling pathways. However, there are few studies on the TRAF gene family in yellow catfish. In this study, the open reading frame (ORF) sequences of TRAF1, TRAF2a, TRAF2b, TRAF3, TRAF4a, TRAF4b, TRAF5, TRAF6 and TRAF7 genes were cloned and identified in yellow catfish. The ORF sequences of the nine TRAF genes of yellow catfish (
TRAF1-7) were 1413-2025 bp in length and encoded 470-674 amino acids. The predicted protein structures of
TRAFs have typically conserved domains compared to mammals. The phylogenetic relationships showed that TRAF genes are conserved during evolution. Gene structure, motifs and syntenic analyses of TRAF genes showed that the exon-intron structure and conserved motifs of TRAF genes are diverse among seven vertebrate species, and the TRAF gene family is relatively conserved evolutionarily. Among them, TRAF1 is more closely related to TRAF2a and TRAF2b, and they may have evolved from a common ancestor. TRAF7 is quite different and distantly related to other TRAFs. Real-time quantitative PCR (qRT-PCR) results showed that all nine
TRAF genes were constitutively expressed in 12 tissues of healthy yellow catfish, with higher mRNA expression levels in the gonad, spleen, brain and gill. After infection with
, the expression levels of nine
TRAF mRNAs were significantly changed in the head kidney, spleen, gill and brain tissues of yellow catfish, of which four genes were down-regulated and one gene was up-regulated in the head kidney; four genes were up-regulated and four genes were down-regulated in the spleen; two genes were down-regulated, one gene was up-regulated, and one gene was up-regulated and then down-regulated in the gill; one gene was up-regulated, one gene was down-regulated, and four genes were down-regulated and then up-regulated in the brain. These results indicate that
TRAF genes might be involved in the immune response against bacterial infection. Subcellular localization results showed that all nine
TRAFs were found localized in the cytoplasm, and
TRAF2a,
TRAF3 and
TRAF4a could also be localized in the nucleus, uncovering that the subcellular localization of TRAF protein may be closely related to its structure and function in cellular mechanism. The results of this study suggest that the
TRAF gene family plays important roles in the immune response against pathogen invasion and will provide basic information to further understand the roles of TRAF gene against bacterial infection in yellow catfish.
Electrocatalytic oxidation of 5‐hydroxymethylfurfural (HMF) offers a renewable approach to produce the value‐added platform chemical 2,5‐furandicarboxylic acid (FDCA). The key for the economic ...viability of this approach is to develop active and selective electrocatalysts. Nevertheless, a reliable catalyst evaluation protocol is still missing, leading to elusive conclusions on criteria for a high‐performing catalyst. Herein, we demonstrate that besides the catalyst identity, secondary parameters such as materials of conductive substrates for the working electrode, concentration of the supporting electrolyte, and electrolyzer configurations have profound impact on the catalyst performance and thus need to be optimized before assessing the true activity of a catalyst. Moreover, we highlight the importance of those secondary parameters in suppressing side reactions, which has long been overlooked. The protocol is validated by evaluating the performance of free‐standing Cu‐foam, and CuCoO modified with NaPO2H2 and Ni, which were immobilized on boron‐doped diamond (BDD) electrodes. Recommended practices and figure of merits in carefully evaluating the catalyst performance are proposed.
Proposal of a measurement protocol for comparison of electrocatalysts for the HMF oxidation with standard evaluation (yield, faradaic efficiency), as well as a new figure of merit (production rate) to compare catalysts independent from setup size. Additionally, the alkaline degradation of HMF is evaluated and taken into account for closing the mass balance in order to assess the true catalyst activity.
Heavy-metal pollution poses severe threat to ecological systems and presents a great challenge for global sustainability. Portable point-of-care sensing platform for detection/monitoring of ...heavy-metal pollution in the environment is urgently demanded. Herein, a highly sensitive, robust, and low-cost microfluidic electrochemical carbon-based sensor (μCS) for detection of trace heavy metals is presented. The miniaturized μCS devices are based on a microfluidic paper channel combined with a novel three-dimensional layout with working and counter electrodes facing each other and analyte flowing along the microfluidic channel between these two electrodes. Pristine graphite foil free of any surface modifier is not only used as the electronically conductive pad but also directly employed as the working electrode for fabricating the μCS. The resulting simple and portable device was applied in Cd2+ and Pb2+ detection using square-wave anodic stripping voltammetry. Detection limits down to 1.2 μg/L for Cd2+ and 1.8 μg/L for Pb2+ can be achieved over the μCS. The μCS devices are also found to be highly robust, and 10 repetitive measurements with a single μCS device resulted to be highly reproducible.
PDF
