Abstract
While exploring the process of CO/CO
2
electroreduction (CO
x
RR) is of great significance to achieve carbon recycling, deciphering reaction mechanisms so as to further design catalytic ...systems able to overcome sluggish kinetics remains challenging. In this work, a model single-Co-atom catalyst with well-defined coordination structure is developed and employed as a platform to unravel the underlying reaction mechanism of CO
x
RR. The as-prepared single-Co-atom catalyst exhibits a maximum methanol Faradaic efficiency as high as 65% at 30 mA/cm
2
in a membrane electrode assembly electrolyzer, while on the contrary, the reduction pathway of CO
2
to methanol is strongly decreased in CO
2
RR. In-situ X-ray absorption and Fourier-transform infrared spectroscopies point to a different adsorption configuration of *CO intermediate in CORR as compared to that in CO
2
RR, with a weaker stretching vibration of the C–O bond in the former case. Theoretical calculations further evidence the low energy barrier for the formation of a H-CoPc-CO
–
species, which is a critical factor in promoting the electrochemical reduction of CO to methanol.
Designing stable single-atom electrocatalysts with lower energy barriers is urgent for the acidic oxygen evolution reaction. In particular, the atomic catalysts are highly dependent on the ...kinetically sluggish acid–base mechanism, limiting the reaction paths of intermediates. Herein, we successfully manipulate the steric localization of Ru single atoms at the Co3O4 surface to improve acidic oxygen evolution by precise control of the anchor sites. The delicate structure design can switch the reaction mechanism from the lattice oxygen mechanism (LOM) to the optimized adsorbate evolution mechanism (AEM). In particular, Ru atoms embedded into cation vacancies reveal an optimized mechanism that activates the proton donor–acceptor function (PDAM), demonstrating a new single-atom catalytic pathway to circumvent the classic scaling relationship. Steric interactions with intermediates at the anchored Ru–O–Co interface played a primary role in optimizing the intermediates’ conformation and reducing the energy barrier. As a comparison, Ru atoms confined to the surface sites exhibit a lattice oxygen mechanism for the oxygen evolution process. As a result, the delicate atom control of the spatial position presents a 100-fold increase in mass activity from 36.96 A gRu(ads) –1 to 4012.11 A gRu(anc) –1 at 1.50 V. These findings offer new insights into the precise control of single-atom catalytic behavior.
In the past decade, tandem mass spectrometry (MS/MS)-based bottom-up proteomics has become the method of choice for analyzing post-translational modifications (PTMs) in complex mixtures. The key to ...the identification of the PTM-containing peptides and localization of the PTM-modified residues is to measure the similarities between the theoretical spectra and the experimental ones. An accurate prediction of the theoretical MS/MS spectra of the modified peptides will improve the similarity measurement. Here, we proposed the deep-learning-based pDeep2 model for PTMs. We used the transfer learning technique to train pDeep2, facilitating the training with a limited scale of benchmark PTM data. Using the public synthetic PTM data sets, including the synthetic phosphopeptides and 21 synthetic PTMs from ProteomeTools, we showed that the model trained by transfer learning was accurate (>80% Pearson correlation coefficients were higher than 0.9), and was significantly better than the models trained without transfer learning. We also showed that accurate prediction of the fragment ion intensities of the PTM neutral loss, for example, the phosphoric acid loss (−98 Da) of the phosphopeptide, will improve the discriminating power to distinguish the true phosphorylated residue from its adjacent candidate sites. pDeep2 is available at https://github.com/pFindStudio/pDeep/tree/master/pDeep2.
Chestnut rose, R. roxburghii Tratt. (Rosaceae) (RR) is an important crop in China due to its nutritional and medicinal values. RR frequently produces trichomes on the surfaces of a diverse range of ...organs, however a genetic component exists to the control of trichome development, with some cultivars having significantly fewer trichomes to others. Certain varieties have fruits that are thickly covered with macroscopic trichomes, which is an undesirable trait for fruit processing and consumption. However, smooth‐fruit cultivars exist, such as R. roxburghii Tratt. f. esetosa Ku (RRE). Despite their economic importance, the anatomical features of trichomes have not been explored in detail for these two chestnut rose germplasms. Here, we investigate the ultrastructure of trichomes distributed on the stem, sepal, and fruit of RR and RRE using transmission electron microscopy (TEM). The internal structure of stem prickle trichomes in RR and RRE was oval in shape and did not contain nucleoli or other organelles. The cell walls of stem prickles in RR are thick and the intercellular spaces occupied with liquid, whereas the cells wall of stem prickles in RRE are thin and have air‐filled intercellular spaces. The cells of sepal acicular trichomes in RR and glandular trichomes (GTs) of sepals in RRE had similar vacuole sizes, cytoplasm content, intercellular spaces, and arrangement of plastids within cells. However, there were osmiophilic granules present in the GTs of RRE. The flagelliform trichomes in the sepals of the two germplasms are composed of oval or rod‐shaped cells. Although the flagelliform trichomes in the sepals of the two germplasms had a similar internal structure, and both contained starch grains and plastids with visible thylakoid membranes, the flagelliform trichomes in the sepals of RR had a thinner cell wall and a higher proportion of cytoplasm which was more evenly distributed across the cell. There were granules that stained heavily with osmium tetroxide which occurred infrequently in the flagelliform trichomes of sepals in RRE but were not observed in RR. On the acicular trichomes of fruit in RR, the flagelliform trichomes and the GTs of fruit in RRE shared similar cell morphology, arrangement and vacuole size as well as intercellular space. Both the fruit flagelliform trichomes and GTs in RRE contain granules which stain heavily with osmium tetroxide, and the GTs contain plastids and starch grains. These differences in trichome cell ultrastructure may be related to developmental processes or biological functions of the trichomes. These results also suggest that the two chestnut rose germplasms are good candidates for further study of trichome ontogeny in the genus and subsequent breeding of the smooth organ trait in this species.
TEM images of trichomes in sepal of R. roxburghii Tratt (RR) and R. roxburghii Tratt. f. esetosa Ku (RRE). (a) TEM of acicular trichomes in sepals of RR; (b–e): Local magnification map of a; (f) TEM of flagellate trichomes in sepals of RR; (g–j): Local magnification map of f; k: TEM map of flagellate trichomes in sepals of RRE; (l–o): Local magnification map of k; (p) TEM of GTs in sepals of RRE; (q–t) Local magnification map of p; cw: Cell wall; V: Vacuoles; PDT: Plastids with dilated thylakoids (triangle); starch grains (asterisk); plastids (white arrow); rod‐shaped cells (black arrow) Scale bars: 10 μm (a, f, k, p); 2 μm (b–e, g–j, l–o, q–t).
The cell walls of stem prickles in RR are thick and the intercellular spaces occupied with liquid, whereas the cells wall of stem prickles in R. roxburghii Tratt. f. esetosa Ku are thin and have air‐filled intercellular spaces.
Both the fruit flagelliform trichomes and GTs in R. roxburghii Tratt. f. esetosa Ku contain granules which stain heavily with osmium tetroxide, and the GTs contain plastids and starch grains.
There were granules that stained heavily with osmium tetroxide which occurred infrequently in the flagelliform trichomes of sepals in R. roxburghii Tratt. f. esetosa Ku, but were not observed in R. roxburghii Tratt.
Although the flagelliform trichomes in the sepals of the two germplasms contained starch grains and plastids with visible thylakoid membranes, the flagelliform trichomes of R. roxburghii Tratt had a thinner cell wall and a higher proportion of cytoplasm which was more evenly distributed across the cell.
Decision-makers (DMs) will face severe challenges when selecting an optimal alternative for an emergency response over multiple time periods. The aim of this paper is to develop a novel dynamic ...emergency decision-making method with probabilistic hesitant fuzzy information for handling emergencies. First, an approach based on the GM(1,1) model for predicting the decision-making information at the next stage is proposed. Second, a new probabilistic hesitant fuzzy distance measure based on the hesitant degree of the probabilistic hesitant fuzzy element is put forward, and a mathematical programming model to determine the stage weights is established. What is more, the closeness degree between each alternative and the ideal alternative is calculated, and the emergency alternatives are ranked on the strength of the technique for order preference by similarity to an ideal solution method. Moreover, a practical example is used to verify the feasibility and rationality of the proposed method.
Living in greener areas has many health benefits, but evidence concerning the effects on blood pressure remains mixed. We sought to assess associations between community greenness and both blood ...pressure and hypertension in Chinese urban dwellers, and whether the associations were mediated by air pollution, body mass index, and physical activity.
We analyzed data from 24,845 adults participating in the 33 Communities Chinese Health Study, which was conducted in Northeastern China during 2009. We measured each participant's blood pressure according to a standardized protocol. We assessed community greenness using two satellite-derived vegetation indexes – the Normalized Difference Vegetation Index (NDVI) and the Soil Adjusted Vegetation Index (SAVI). Particulate matter ≤2.5 μm and nitrogen dioxide were used as proxies of ambient air pollution. We applied generalized linear mixed models to investigate the association between greenness and blood pressure. We also performed mediation analyses.
Living in greener areas was associated with lower blood pressure and hypertension prevalence; an interquartile range increase in both NDVI500-m and SAVI500-m were significantly associated with reductions in systolic blood pressure of 0.82 mm Hg (95% CI: −1.13, −0.51) and 0.89 mm Hg (95% CI: −1.21, −0.57), respectively. The same increases in greenness were also significantly associated with a 5% (95% CI: 1%, 8%) and 5% (95% CI: 1%, 9%) lower odds of having hypertension, respectively. These associations remained consistent in sensitivity analyses. The associations were stronger among women than men. Air pollutants and body mass index partly mediated the associations, but there was no evidence of mediation effects for physical activity.
Our findings indicate beneficial associations between community greenness and blood pressure in Chinese adults, especially for women. Air pollution and body mass index only partly mediated the associations.
•Evidence on greenness and blood pressure is scarce in China.•We conducted a cross-sectional study in 24,845 Chinese urban dwellers.•Associations of greenness with blood pressure metrics were examined.•Greenness levels were beneficially associated with blood pressure.•Air pollution and BMI partly mediated the greenness-blood pressure association.
Gliomas are the most common form of malignant tumour in the central nervous system. However, the molecular mechanism of the tumorigenesis and progression of gliomas remains unclear. In this study, we ...used the GEO database to identify genes differentially expressed in gliomas and predict the prognosis of glioma. We observed that ASPM mRNA was increased obviously in glioma tissue, and higher ASPM mRNA expression predicted worse disease prognosis. ASPM was highly expressed in glioma cell lines U87‐MG and U251, and knockdown of ASPM expression in these cells significantly repressed the proliferation, migration and invasion ability and induced G0/G1 phase arrest. In addition, down‐regulation of ASPM suppressed the growth of glioma in nude mice. Five potential binding sites for transcription factor FoxM1 were predicted in the ASPM promoter. FoxM1 overexpression significantly increased the expression of ASPM and promoted the proliferation and migration of glioma cells, which was abolished by ASPM ablation. ChIP and dual‐luciferase reporter analysis confirmed that FoxM1 bound to the ASPM promoter at −236 to ‐230 bp and −1354 to ‐1348 bp and activated the transcription of ASPM directly. Collectively, our results demonstrated for the first time that aberrant ASPM expression mediated by transcriptional regulation of FoxM1 promotes the malignant properties of glioma cells.
In this communication, a bandwidth-enhanced antenna pair with a tunable electric field (<inline-formula> <tex-math notation="LaTeX">E </tex-math></inline-formula>-field) null for the fifth-generation ...(5G) mobile phone application is presented. The proposed antenna pair is composed of a stub-loaded inverted-F antenna (IFA) and a simple feeding network. The stub-loaded IFA can obtain a wider impedance bandwidth and a feeding network is designed to excite the orthogonal dipole mode and adjust the <inline-formula> <tex-math notation="LaTeX">E </tex-math></inline-formula>-field null position. By adjusting the phase shifter in the feeding network, the <inline-formula> <tex-math notation="LaTeX">E </tex-math></inline-formula>-field null can be moved to the feeding position of the IFA, achieving excellent isolation performance. A sub-6 GHz antenna pair is simulated and shows an isolation of better 16.5 dB within the N78 (3.3-3.8 GHz) band. By arranging the proposed antenna pair along two long edges of the ground plane, an <inline-formula> <tex-math notation="LaTeX">8\times 8 </tex-math></inline-formula> multiple-input multiple-output (MIMO) system is designed, fabricated, and measured. The measured results show that the MIMO system could achieve isolation of better than 19.5 dB and envelope correlation coefficients (ECCs) of lower than 0.03. The measured total efficiencies are greater than 43% for each port. The proposed antenna reveals a novel decoupling strategy for wider bandwidth while retaining the isolation performance and compact size based on a pair of orthogonal mode.
Establishing an accurate, simple, and rapid serodiagnosis method aiming for specific cancer antigens is critically important for the clinical diagnosis, therapy, and prognostication of cancer. ...Currently, surface-enhanced Raman scattering (SERS) readout techniques challenge fluorescent-based detection methods in terms of both optical stability and more importantly multiple detection capability, which become more desirable for clinical diagnostics. We thus started using an interference-free mixing SERS emission (m-SERS) readout to simultaneously indicate, for the first time, three specific liver cancer antigens, including α-fetoprotein (AFP), carcinoembryonic antigen (CEA), and ferritin (FER), even in one clinical serum sample. Here, three triple bonds (CN and CC) coded SERS tags contribute separate SERS emissions located at 2105, 2159, and 2227 cm–1, respectively; must have one-to-one correspondence from AFP, to FER, to CEA, In the process of detection, the mature double antibody sandwich allows the formation of microscale core–satellite assembly structure between a magnetic bead (MB) and single SERS tags, and therefore a pure and single SERS emission can be observed under the routine excitation laser spot. Because of the action of magnetic force, the uniform 3D packing of SERS tags absorbed MBs will in contrast generate a so-called m-SERS signals. With the help of enrichment and separation by MBs, the proposed m-SERS immunoassay provides an extremely rapid, sensitive, and accurate solution for multiplex detection of antigens or other biomarkers. Herein, the limit of detection (LOD) for simultaneous m-SERS detection of AFP, CEA, and FER was 0.15, 20, and 4 pg/mL, respectively. As expected for 39 clinical serum samples, simultaneous detection of ternary specific antigens can significantly improve the accuracy of liver cancer diagnosis.
We present a sequence-tag-based search engine, Open-pFind, to identify peptides in an ultra-large search space that includes coeluting peptides, unexpected modifications and digestions. Our method ...detects peptides with higher precision and speed than seven other search engines. Open-pFind identified 70-85% of the tandem mass spectra in four large-scale datasets and 14,064 proteins, each supported by at least two protein-unique peptides, in a human proteome dataset.
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