The nanocomposite photocatalysts of quasi-noble-metal graphene quantum dots (GQDs) deposited SnO2 with oxygen vacancies (VOs) were prepared through a simple two-step reactions process. The obtained ...nanocomposites exhibited much enhanced photodegradation activity for the extended visible-light response as well as raised charge-separation efficiency. Display omitted
Quasi-noble-metal graphene quantum dots (GQDs) deposited stannic oxide (SnO2) with oxygen vacancies (VOs) were prepared by simply sintering SnO2 and citric acid (CA) together. The redox process between SnO2 and GQDs shows the formation of oxygen vacancy states below the conduction band of stannic oxide. The produced VOs obviously extend the optical absorption region of SnO2 to the visible-light region. Meanwhile, GQDs can effectively improve the charge-separation efficiency via a quasi function like noble metal and promote the visible-light response to some degree. In addition, the samples calcinated at 450°C reveals the best performance because of its relatively high concentrations of VOs. What is more, the possible degradation mechanism has been inferred as extended visible-light response as well as raised charge-separation efficiency has also been put forward. Our work may offer a simple strategy to combine the defect modulation and noble metal deposition simultaneously for efficient photocatalysis.
To address the problem of long-tail distribution for the large vocabulary object detection task, existing methods usually divide the whole categories into several groups and treat each group with ...different strategies. These methods bring the following two problems. One is the training inconsistency between adjacent categories of similar sizes, and the other is that the learned model is lack of discrimination for tail categories which are semantically similar to some of the head categories. In this paper, we devise a novel Adaptive Class Suppression Loss (ACSL) to effectively tackle the above problems and improve the detection performance of tail categories. Specifically, we introduce a statistic-free perspective to analyze the long-tail distribution, breaking the limitation of manual grouping. According to this perspective, our ACSL adjusts the suppression gradients for each sample of each class adaptively, ensuring the training consistency and boosting the discrimination for rare categories. Extensive experiments on long-tail datasets LVIS and Open Images show that the our ACSL achieves 5.18% and 5.2% improvements with ResNet50-FPN, and sets a new state of the art. Code and models are available at https://github.com/CASIA-IVA-Lab/ACSL.
COVID-19 is mainly associated with respiratory distress syndrome, but a subset of patients often present gastrointestinal (GI) symptoms. Imbalances of gut microbiota have been previously linked to ...respiratory virus infection. Understanding how the gut–lung axis affects the progression of COVID-19 can provide a novel framework for therapies and management. In this study, we examined the gut microbiota of patients with COVID-19 (
n
= 47) and compared it to healthy controls (
n
= 19). Using shotgun metagenomic sequencing, we have identified four microorganisms unique in COVID-19 patients, namely
Streptococcus thermophilus
,
Bacteroides oleiciplenus
,
Fusobacterium ulcerans
, and
Prevotella bivia
. The abundances of
Bacteroides stercoris
,
B. vulgatus
,
B. massiliensis
,
Bifidobacterium longum
,
Streptococcus thermophilus
,
Lachnospiraceae bacterium
5163FAA,
Prevotella bivia
,
Erysipelotrichaceae bacterium
6145, and
Erysipelotrichaceae bacterium
2244A were enriched in COVID-19 patients, whereas the abundances of
Clostridium nexile
,
Streptococcus salivarius
,
Coprococcus catus
,
Eubacterium hallii
,
Enterobacter aerogenes
, and
Adlercreutzia equolifaciens
were decreased (
p
< 0.05). The relative abundance of butyrate-producing
Roseburia inulinivorans
is evidently depleted in COVID-19 patients, while the relative abundances of
Paraprevotella
sp. and the probiotic
Streptococcus thermophilus
were increased. We further identified 30 KEGG orthology (KO) modules overrepresented, with 7 increasing and 23 decreasing modules. Notably, 15 optimal microbial markers were identified using the random forest model to have strong diagnostic potential in distinguishing COVID-19. Based on Spearman’s correlation, eight species were associated with eight clinical indices. Moreover, the increased abundance of
Bacteroidetes
and decreased abundance of
Firmicutes
were also found across clinical types of COVID-19. Our findings suggest that the alterations of gut microbiota in patients with COVID-19 may influence disease severity. Our COVID-19 classifier, which was cross-regionally verified, provides a proof of concept that a set of microbial species markers can distinguish the presence of COVID-19.
A successful structure-based design of a class of non-peptide small-molecule MDM2 inhibitors targeting the p53−MDM2 protein−protein interaction is reported. The most potent compound 1d binds to MDM2 ...protein with a K i value of 86 nM and is 18 times more potent than a natural p53 peptide (residues 16−27). Compound 1d is potent in inhibition of cell growth in LNCaP prostate cancer cells with wild-type p53 and shows only a weak activity in PC-3 prostate cancer cells with a deleted p53. Importantly, 1d has a minimal toxicity to normal prostate epithelial cells. Our studies provide a convincing example that structure-based strategy can be employed to design highly potent, non-peptide, cell-permeable, small-molecule inhibitors to target protein−protein interaction, which remains a very challenging area in chemical biology and drug design.
Steady‐state visual evoked potentials (SSVEP), significant in brain‐computer interfaces (BCI) and medical diagnostics, benefit from enhanced signal processing for improved analysis and ...interpretation. This study introduces a novel enhancement algorithm for SSVEP electroencephalogram (EEG) signals, employing fractional‐order differentiation operators combined with image processing techniques. Utilizing fractional‐order differentiation within a Laplace pyramid framework, the algorithm achieves hierarchical signal enhancement, facilitating detailed feature extraction and emphasizing SSVEP signal characteristics. This innovative approach merges the precision of fractional calculus with the structural benefits of the Laplace pyramid, leading to enhanced signal clarity and feature discrimination. The efficacy of this method was validated using canonical correlation analysis (CCA), filter bank CCA (FBCCA), and task‐related component analysis (TRCA) on a public dataset. Compared to conventional methods, our algorithm not only mitigates trend components in SSVEP signals but also significantly boosts the recognition accuracy of CCA, FBCCA, and TRCA algorithms. Experimental results indicate a marked improvement in recognition precision, underscoring the algorithm's potential to advance SSVEP‐based BCI research.
This study introduces a novel SSVEP‐EEG signal enhancement algorithm using fractional‐order differentiation and the Laplace pyramid, enhancing signal clarity and feature distinctiveness. Tested with CCA, FBCCA, and TRCA on a public dataset, the algorithm significantly improves recognition accuracy, showcasing a notable advancement in SSVEP‐based BCI research.
Objective
To compare the safety, efficacy, and prognosis of stent-assisted coiling (SAC) versus coiling alone (CA) in the treatment of ruptured anterior communicating artery aneurysms (ACoAAs).
...Methods
The clinical and follow-up data of ruptured ACoAAs treated with endovascular treatment in our center from January 2011 to January 2021 were retrospectively collected. Patients were divided into an SAC group and a CA group based on whether stents were used, after which the two groups were matched for propensity scores. The general clinical data, embolization effect, perioperative complications, clinical, and follow-up results after matching were compared.
Results
A total of 354 patients were enrolled, of whom 147 patients (41.5%) received SAC and the rest received CA. Comparison baseline of two groups showed that patients with a larger diameter, wide neck, irregular morphology, and anterior direction were more likely to receive SAC. After propensity score matching, 113 patients were included in each group. Immediately postoperative angiography results showed that the complete embolization rate of patients in the SAC group was significantly lower than that in the CA group (62.8% vs. 76.1%, p = 0.03). There were no significant differences between the two groups in the incidence of perioperative complications, mortality, poor prognosis at discharge or follow-up, mid-term complete occlusion rate and recurrence rate.
Conclusion
The stent-assisted treatment of ruptured ACoAAs did not increase the risk of perioperative complications or the probability of poor prognosis, indicating that SAC treatment of ruptured ACoAAs is safe and feasible and has a reliable mid-term cure rate.
Pt@SiO
2
@TiO
2
composites with an average diameter of about 120 nm were synthesized by an aqueous method. Morphology, microstructure, and light absorption performance of as-prepared samples were ...characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV–Vis diffuse reflectance spectroscopy. The results indicate that 5-nm-thick SiO
2
interlayer coated on the Pt nanoparticles were used to separate the Pt from the TiO
2
. The covering SiO
2
layer between Pt nanoparticles and TiO
2
layer present a wide spectral response. The enhanced photocatalytic efficiency under both the full spectrum and visible light can be attributed to the existence of Pt nanoparticles and interlayer SiO
2
. The coupling processes between TiO
2
and plasmon were presented and the mechanism was discussed. The localized surface plasmon resonance effect of Pt nanoparticles is the main reason for the enhanced photocatalytic activity of the composite Pt@SiO
2
@TiO
2
.
Ageing conditions and braided structures will affect dynamic damage and failure mechanisms of 3D braided composites. Here we report the influence of thermo-oxidative ageing on impact compression ...behaviors of 3D braided composite with and without axial yarns, i.e., four directional (3D4d) and five directional (3D5d) braided composites. We found a significant difference in mechanical properties between epoxy resins and composites after ageing. The impact compressive strength of epoxy resins declined rapidly and then slowly, while the composites decreased continuously, with the increase of ageing days. The interfacial debonding is main degradation mechanism for both braided composites at the later ageing stage. Thermo-oxidative ageing accelerates the inner damage evolution which propagates from surface cracks. Compared with 3D4d braided composites, the 3D5d braided structure has higher strength retaining level after ageing. In addition, the 3D5d braided samples have higher resistance to impact deformation and lower crack propagation. Finite element analysis (FEA) results revealed that 3D5d composites showed higher load carrying capacity and less damages than 3D4d composites.
High mechanical advantage as well as low and steady slide speed within the working stroke
S
n
are the fundamental requirements for the working mechanism of servo-mechanical press. Currently, the ...Crank-Triangular Linkage-Elbow (CTLE) mechanism has attracted more and more attention from researchers and manufacturers of servo presses. This paper presents a new analysis and design method of CTLE. The mechanism is decomposed into two sub-units: crank and triangular-linkage elbow, followed by the kinematic and force analysis of each sub-unit. The influences of each structural parameter on the working performance are obtained and can be used as the basis for preliminary design. Through the offset design, the mechanical advantage peaks of the two units,
MA
1max
and
MA
2max
, do not occur at the same time:
MA
1max
is located near
S
n
, while
MA
2max
is just at BDC (Bottom Dead Center). Because the mechanical advantage of the whole mechanism is the product of the two subunits, the designed mechanism can obtain high and steady mechanical advantage together with low and steady slide speed within
S
n
. After preliminary design, the scheme can be further modified by numerical simulation and optimization. Hence the design efficiency can be improved.
The H2O2 + HO → HO2 + H2O reaction is an important reservoir for both radicals of HO and HO2 catalyzing the destruction of O3. Here, this reaction assisted by NH3 and HCOOH catalysts was explored ...using the CCSD(T)-F12a/cc-pVDZ-F12//M06-2X/aug-cc-pVTZ method and canonical variational transition state theory with small curvature tunneling. Two possible sets of mechanisms, (i) one-step routes and (ii) stepwise processes, are possible. Our results show that in the presence of both NH3 and HCOOH catalysts under relevant atmospheric temperature, mechanism (i) is favored both energetically and kinetically than the corresponding mechanism (ii). At 298 K, the relative rate for mechanism (i) in the presence of NH3 (10, 2900 ppbv) and HCOOH (10 ppbv) is respectively 3–5 and 2–4 orders of magnitude lower than that of the water-catalyzed reaction. This is due to a comparatively lower concentration of NH3 and HCOOH than H2O which indicates the positive water effect under atmospheric conditions. Although NH3 and HCOOH catalysts play a negligible role in the reservoir for both radicals of HO and HO2 catalyzing the destruction of O3, the current study provides a comprehensive example of how acidic and basic catalysts assisted the gas-phase reactions.
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