Under topological guidance, the self‐assembly process based on a tetratopic porphyrin synthon results in a hydrogen‐bonded organic framework (HOF) with the predicted square layers topology (sql) but ...unsatisfied stability. Strikingly, simply introducing a transition metal in the porphyrin center does not change the network topology but drastically causes noticeable change on noncovalent interaction, orbital overlap, and molecular geometry, therefore ultimately giving rise to a series of metalloporphyrinic HOFs with high surface area, and excellent stability (intact after being soaked in boiling water, concentrated HCl, and heated to 270 °C). On integrating both photosensitizers and catalytic sites into robust backbones, this series of HOFs can effectively catalyze the photoreduction of CO2 to CO, and their catalytic performances greatly depend on the chelated metal species in the porphyrin centers. This work enriches the library of stable functional HOFs and expands their applications in photocatalytic CO2 reduction.
Crystallographic and computational studies on a series of porphyrinic hydrogen‐bonded organic frameworks (HOFs) reveal that metallization of porphyrin centers greatly alters the orbital overlap of the adjacent porphyrin, the geometry of the molecule/layer, and the strength of noncovalent interactions. Therefore, metalloporphyrin HOFs exhibit much higher stability, surface area, and catalytic activity than metal‐free porphyrinic HOFs.
Rational synthesis of hydrogen‐bonded organic frameworks (HOFs) with predicted structure has been a long‐term challenge. Herein, by using the efficient, simple, low‐cost, and scalable ...mechanosynthesis, we demonstrate that reticular chemistry is applicable to HOF assemblies based on building blocks with different geometry, connectivity, and functionality. The obtained crystalline HOFs show uniform nano‐sized morphology, which is challenging or unachievable for conventional solution‐based methods. Furthermore, the one‐pot mechanosynthesis generated a series of Pd@HOF composites with noticeably different CO oxidation activities. In situ DRIFTS studies indicate that the most efficient composite, counterintuitively, shows the weakest CO affinity to Pd sites while the strongest CO affinity to HOF matrix, revealing the vital role of porous matrix to the catalytic performance. This work paves a new avenue for rational synthesis of HOF and HOF‐based composites for broad application potential.
Efficient and green mechanochemistry was performed to realize the reticular synthesis of hydrogen‐bonded organic frameworks with predictable structures. Moreover, a series of Pd@HOF composites were generated by the one‐pot mechanosynthesis, which showed different catalytic activities for CO oxidation. The synergetic effect between Pd and HOF was revealed by in situ DRIFTS, proving the application potential of functionalized HOF‐composites.
Images/videos captured from outdoor visual devices are usually degraded by turbid media, such as haze, smoke, fog, rain, and snow. Haze is the most common one in outdoor scenes due to the atmosphere ...conditions. In this paper, a novel deep learning-based architecture (denoted by MSRL-DehazeNet) for single image haze removal relying on multi-scale residual learning (MSRL) and image decomposition is proposed. Instead of learning an end-to-end mapping between each pair of hazy image and its corresponding haze-free one adopted by most existing learning-based approaches, we reformulate the problem as restoration of the image base component. Based on the decomposition of a hazy image into the base and the detail components, haze removal (or dehazing) can be achieved by both of our multi-scale deep residual learning and our simplified U-Net learning only for mapping between hazy and haze-free base components, while the detail component is further enhanced via the other learned convolutional neural network (CNN). Moreover, benefited by the basic building block of our deep residual CNN architecture and our simplified U-Net structure, the feature maps (produced by extracting structural and statistical features), and each previous layer can be fully preserved and fed into the next layer. Therefore, possible color distortion in the recovered image would be avoided. As a result, the final haze-removed (or dehazed) image is obtained by integrating the haze-removed base and the enhanced detail image components. Experimental results have demonstrated good effectiveness of the proposed framework, compared with state-of-the-art approaches.
Human pepsinogens are considered promising serological biomarkers for the screening of atrophic gastritis (AG) and gastric cancer (GC). However, there has been controversy in the literature with ...respect to the validity of serum pepsinogen (SPG) for the detection of GC and AG. Consequently, we conducted a systematic review and meta-analysis to assess the diagnostic accuracy of SPG in GC and AG detection.
We searched PubMed, Embase, and the Chinese National Knowledge Infrastructure (CNKI) for correlative original studies published up to September 30, 2014. The summary sensitivity, specificity, positive diagnostic likelihood ratio (DLR+), negative diagnostic likelihood ratio (DLR-), area under the summary receiver operating characteristic curve (AUC) and diagnostic odds ratio (DOR) were used to evaluate SPG in GC and AG screening based on bivariate random effects models. The inter-study heterogeneity was evaluated by the I2 statistics and publication bias was assessed using Begg and Mazumdar's test. Meta-regression and subgroup analyses were performed to explore study heterogeneity.
In total, 31 studies involving 1,520 GC patients and 2,265 AG patients were included in the meta-analysis. The summary sensitivity, specificity, DLR+, DLR-, AUC and DOR for GC screening using SPG were 0.69 (95% CI: 0.60-0.76), 0.73 (95% CI: 0.62-0.82), 2.57 (95% CI: 1.82-3.62), and 0.43 (95% CI: 0.34-0.54), 0.76 (95% CI: 0.72-0.80) and 6.01 (95% CI: 3.69-9.79), respectively. For AG screening, the summary sensitivity, specificity, DLR+, DLR-, AUC and DOR were 0.69 (95% CI: 0.55-0.80), 0.88 (95% CI: 0.77-0.94), 5.80 (95% CI: 3.06-10.99), and 0.35 (95% CI: 0.24-0.51), 0.85 (95% CI: 0.82-0.88) and 16.50 (95% CI: 8.18-33.28), respectively. In subgroup analysis, the use of combination of concentration of PGI and the ratio of PGI:PGII as measurement of SPG for GC screening yielded sensitivity of 0.70 (95% CI: 0.66-0.75), specificity of 0.79 (95% CI: 0.79-0.80), DOR of 6.92 (95% CI: 4.36-11.00), and AUC of 0.78 (95% CI: 0.72-0.81), while the use of concentration of PGI yielded sensitivity of 0.55 (95% CI: 0.51-0.60), specificity of 0.79 (95% CI: 0.76-0.82), DOR of 6.88 (95% CI: 2.30-20.60), and AUC of 0.77 (95% CI: 0.73-0.92). For AG screening, the use of ratio of PGI:PGII as measurement of SPG yielded sensitivity of 0.69 (95% CI: 0.52-0.83), specificity of 0.84 (95% CI: 0.68-0.93), DOR of 11.51 (95% CI: 6.14-21.56), and AUC of 0.83 (95% CI: 0.80-0.86), the use of combination of concentration of PGI and the ratio of PGI:PGII yield sensitivity of 0.79 (95% CI: 0.72-0.85), specificity of 0.89 (95% CI: 0.85-0.93), DOR of 24.64 (95% CI: 6.95-87.37), and AUC of 0.87 (95% CI: 0.81-0.92), concurrently, the use of concentration of PGI yield sensitivity of 0.46 (95% CI: 0.38-0.54), specificity of 0.93 (95% CI: 0.91-0.95), DOR of 19.86 (95% CI: 0.86-456.91), and AUC of 0.86 (95% CI: 0.52-1.00).
SPG has great potential as a noninvasive, population-based screening tool in GC and AG screening. In addition, given the potential publication bias and high heterogeneity of the included studies, further high quality studies are required in the future.
Embedding plasmonic metals in metal–organic frameworks (MOFs) can build an advanced visible‐light photocatalyst architecture utilizing the localized surface plasmon resonance (LSPR) effect, while the ...practical performances have been restricted by the sluggish charge transfer at metal–MOF interface and through the secondary building units (SBUs) of the adopted carboxylate MOFs currently. Herein, a pyrazolate Ni‐MOF (PFC‐9) featured with an 1D SBU chain is selected to be the host catalyst to immobilize Au nanoparticles as a novel and optimized construction for LSPR photocatalysis. Compared with the common 3D‐connected SBUs of carboxyl‐ZrOx and pyrazole‐NiOx configurations in the reference MOFs, the 1D (−Ni−NPz−NPz−)∞ chain in PFC‐9 creates abundant Au/MOF contacts, a short and low‐resistant pathway for Au‐to‐Ni2+ transport of hot electrons, and enables fluent electron utilization at the continuous active Ni sites. Consequently, the Au/PFC‐9 photocatalyst achieves the optimum activity for visible‐light‐driven H2 production. This work shows an example to promote the LSPR‐sensitized photocatalysis taking the advantage of MOFs’ structural tunability, providing significant guidance for the rational design of highly efficient photocatalysts.
A novel Au/MOF photocatalyst is constructed by taking the advantage of the pyrazole groups and catalytically active Ni2+ nodes in the 1D coordination chain of PFC‐9. The short‐range and low‐resistant hot‐electron transfer, from Au to Ni and throughout the continuous Ni sites, results in optimum activity for Au‐sensitized photocatalytic H2 production superior to cases without 1D pyrazolate secondary building units.
This article presents a four-phase current-mode hysteretic-controlled DC-DC buck converter with fixed-frequency double-adaptive-bound (DAB) control. In prior current-mode converter designs, there ...exists undesired output DC error caused by control loop delays and mismatches between the RC current sensing network and the DC resistance (DCR) of the power inductor. Circuit delay is also an obstacle in achieving higher switching frequency and multi-phase operation. To address these issues, ratioed sensing RC network and digital output DC calibration are proposed. To reduce the efficiency degradation caused by imbalanced phase current, digital current balancing (CB) calibration is also developed. To maintain a high efficiency with a wide output load range, digital active-phase-count (APC) function was also introduced, with burst mode (BM) to improve transient responses at fast load current steps. The proposed converter has been fabricated in 180-nm CMOS process and measured at 10 and 25 MHz with 18-to-100-nH miniature 0402 inductors, converting 1.8-V supply (<inline-formula> <tex-math notation="LaTeX">\text{V}_{\mathrm{ IN}} </tex-math></inline-formula>) to 0.6-1.5-V output with 93.9% peak efficiency.
Health organizations have relied heavily on social distancing to limit the spread of the COVID-19 pandemic. The purpose of this research is to examine what factors can influence customers' ...evaluations of social distancing as well as how and when these evaluations drive their usage of chatbot services. Using structural equation modeling to analyze the experimental data from 200 U.S. consumers, we found that when the service situation is utilitarian (hedonic) in nature, customers' contamination fear influences their chatbot usage during service encounters through their social distancing attitudes (subjective norms) and then perceived usefulness of chatbots. Our findings provide meaningful theoretical contributions and practical implications.
Previous studies have shown that miR-144-3p might be a potential biomarker in non-small cell lung cancer (NSCLC). Nevertheless, the comprehensive mechanism behind the effects of miR-144-3p on the ...origin, differentiation, and apoptosis of NSCLC, as well as the relationship between miR-144-3p and clinical parameters, has been rarely reported.
We investigated the correlations between miR-144-3p expression and clinical characteristics through data collected from Gene Expression Omnibus (GEO) microarrays, the relevant literature, The Cancer Genome Atlas (TCGA), and real-time quantitative real-time PCR (RT-qPCR) analyses to determine the clinical role of miR-144-3p in NSCLC. Furthermore, we investigated the biological function of miR-144-3p by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Protein-protein interaction (PPI) network was created to identify the hub genes.
From the comprehensive meta-analysis, the combined SMD of miR-144-3p was - 0.95 with 95% CI of (- 1.37, - 0.52), indicating that less miR-144-3p was expressed in the NSCLC tissue than in the normal tissue. MiR-144-3p expression was significantly correlated with stage, lymph node metastasis and vascular invasion (all P < 0.05). As for the bioinformatics analyses, a total of 37 genes were chosen as the potential targets of miR-144-3p in NSCLC. These promising target genes were highly enriched in various key pathways such as the protein digestion and absorption and the thyroid hormone signaling pathways. Additionally, PPI revealed five genes-C12orf5, CEP55, E2F8, STIL, and TOP2A-as hub genes with the threshold value of 6.
The current study validated that miR-144-3p was lowly expressed in NSCLC. More importantly, miR-144-3p might function as a latent tumor biomarker in the prognosis prediction for NSCLC. The results of bioinformatics analyses may present a new method for investigating the pathogenesis of NSCLC.
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