Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 213
Filtrar
1.
BMC Surg ; 24(1): 307, 2024 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-39395969

RESUMO

PURPOSE: This study aimed to assess the safety and efficacy of percutaneous transhepatic cholangiography drainage (PTCD) and endoscopic retrograde cholangiopancreatography (ERCP) in palliative drainage and preoperative biliary drainage for treating malignant obstructive jaundice (MOJ). METHODS: A total of 520 patients with MOJ who underwent PTCD or ERCP were enrolled and classified into palliative drainage group and preoperative biliary drainage group. Baseline characteristics, liver function, blood routine, complications were compared among the groups. RESULTS: The technical success rates for PTCD and ERCP in palliative group were 97.1% and 85.9%. In palliative drainage group, PTCD had higher levels of total bilirubin (TB) reduction (53.0 (30.0,97.0) vs. 36.8 (17.9,65.0), p < 0.001) and direct bilirubin (DB) reduction (42.0 (22.0,78.5) vs. 28.0 (12.0,50.8), p = 0.001) than ERCP. However, PTCD was associated with higher rates of drainage tube displacement (20 cases, 11.8%), while ERCP had a higher incidence of biliary infection (39 cases, 22.8%) and pancreatitis (7 cases, 4.1%). In preoperative drainage group, PTCD achieved a 50% reduction in total bilirubin faster than ERCP (7.1 days vs. 10.5 days). And the time from palliation of jaundice to surgery was 24.2 days in PTCD group and 35.7 days in ERCP group, a statistically significant difference (Student's t test, p = 0.017). CONCLUSION: Both PTCD and ERCP could improve liver function for MOJ patients. PTCD seems to offer better outcomes in jaundice reduction and liver function improvement in palliative drainage, but requires careful postoperative management. In preoperative biliary drainage, PTCD may be a better preoperative bridge to improve liver function and control infection.


Assuntos
Colangiografia , Colangiopancreatografia Retrógrada Endoscópica , Drenagem , Icterícia Obstrutiva , Cuidados Paliativos , Cuidados Pré-Operatórios , Humanos , Icterícia Obstrutiva/cirurgia , Icterícia Obstrutiva/etiologia , Drenagem/métodos , Masculino , Estudos Retrospectivos , Feminino , Colangiopancreatografia Retrógrada Endoscópica/métodos , Pessoa de Meia-Idade , Idoso , Colangiografia/métodos , Cuidados Paliativos/métodos , Cuidados Pré-Operatórios/métodos , Resultado do Tratamento , Adulto
2.
Chem Commun (Camb) ; 2024 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-39391942

RESUMO

Covalent organic frameworks (COFs) have emerged as promising platforms for the construction of single-atom and dual-atom catalysts (SACs and DACs), owing to their well-defined structures, tunable pore sizes, and abundant active sites. In recent years, the development of COF-based SACs and DACs as highly efficient catalysts has witnessed a remarkable surge. The synergistic interplay between the metal active sites and the COF has established the design and fabrication of COF-based SACs and DACs as a prominent research area in electrocatalysis. These catalytic materials exhibit promising prospects for applications in energy storage and conversion devices. This review summarizes recent advances in the design, synthesis, and applications of COF-based SACs and DACs for oxygen catalysis. The catalytic mechanisms of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are comprehensively explored, providing a comparative analysis to elucidate the correlation between the structure and performance, as well as their functional attributes in battery devices. This review highlights a promising approach for future research, emphasizing the necessity of rational design, breakthroughs, and in-situ characterization to further advance the development of high-performance COF-based SACs and DACs for sustainable energy applications.

3.
Dalton Trans ; 53(40): 16470-16474, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-39356491

RESUMO

Bismuth(III) alkanethiolates [Bi(SR)3] formed by reacting Bi2O3 with alkanethiols (RSH) undergo a UV-blue light driven ligand-to-metal charge transfer photoreduction to disulfides and Bi colloids, which are then oxidised to Bi2O3 by dissolved oxygen and reconverted to Bi(SR)3 by RSH to prepare for the next Bi-Bi2O3 photoredox cycle, forming a basis for Bi(III)-catalysed thiol-to-disulfide conversion.

4.
Nanoscale ; 2024 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-39445401

RESUMO

By virtue of the high carrier mobility, diverse electronic band structures, excellent electrostatic tunability, easy integration, and strong light-harvesting capability, 2D layered materials (2DLMs) have emerged as compelling contenders in the realm of photodetection and ushered in a new era of optoelectronic industry. In contrast to powered devices, self-driven photodetectors boast a wealth of advantages, notably low dark current, superior signal-to-noise ratio, low energy consumption, and exceptional compactness. Nevertheless, the construction of self-driven 2DLM photodetectors based on traditional p-n, homo-type, or Schottky heterojunctions, predominantly adopting a vertical configuration, confronts insurmountable dilemmas such as intricate fabrication procedures, sophisticated equipment, and formidable interface issues. In recent years, worldwide researchers have been devoted to pursuing exceptional strategies aimed at achieving the self-driven characteristics. This comprehensive review offers a methodical survey of the emergent paradigms toward self-driven photodetectors constructed from 2DLMs. Firstly, the burgeoning approaches employed to realize diverse self-driven 2DLM photodetectors are compiled, encompassing strategies such as strain modulation, thickness tailoring, structural engineering, asymmetric ferroelectric gating, asymmetric contacts (including work function, contact length, and contact area), ferroelectricity-enabled bulk photovoltaic effect, asymmetric optical antennas, among others, with a keen eye on the fundamental physical mechanisms that underpin them. Subsequently, the prevalent challenges within this research landscape are outlined, and the corresponding potential approaches for overcoming these obstacles are proposed. On the whole, this review highlights new device engineering avenues for the implementation of bias-free, high-performance, and highly integrated 2DLM optoelectronic devices.

5.
Sci Data ; 11(1): 1045, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39333104

RESUMO

Daily meteorological observation data of the early period (pre-1950) were critically important for investigating the long-term trends and multi-decadal scale variability of extreme climate events. The high-resolution surface air temperature (SAT) data for time period before 1950 are lacking in China. We extended the SAT observations of China back to 1840 through developing a pre-1950 daily SAT dataset. The early-period daily SAT were manually corrected for the input and clerical errors, and then according to the length or coverage of time, the main series for each of the cities was determined. The observation time system of unknown sites was determined by the minimum difference method. After these operations, the data of all sites were unified into the same format. By using the ridge regressions established based on data from modern reference stations, the missing maximum temperature (Tmax) and minimum temperature (Tmin) were interpolated. The early-period data were combined with modern data to form the long-term daily SAT dataset of 1840-2020 in China. RHtest software was used to detect and adjust the inhomogeneities in the station data series. Finally, the century-long homogenized daily SAT dataset including 45 key city stations in China was obtained. Among the stations, there are 20 stations with observation record more than one hundred years. The length of temperature observation series of 17 stations is between 80 and 100 years. The series length of the remaining 7 stations is between 68 and 80 years. Finally, the angular distance weighting (ADW) method was used to interpolate the data into grid products, and the grid size is 2.5 ° × 2.5 °. The dataset was named CUG-CMA CHDT, which is applicable in monitoring, studies and assessments of regional extreme temperature change and variability in China.

6.
Plants (Basel) ; 13(18)2024 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-39339588

RESUMO

Silique development exerts significant impacts on crop yield. CRPs (Cysteine-rich peptides) can mediate cell-cell communication during plant reproduction and development. However, the functional characterization and regulatory mechanisms of CRPs in silique development remain unclear. In this study, we identified many CRP genes downstream of the CRP gene TPD1 (TAPETUM DETERMINANT1) during silique development using a microarray assay. The novel Arabidopsis thaliana pollen-borne CRPs, the PCP-Bs (for pollen coat protein B-class) gene AtPCP-Ba, along with TPD1, are essential for silique development. The AtPCP-Ba was significantly down-regulated in tpd1 flower buds but up-regulated in OE-TPD1 flower buds and siliques. The silencing of AtPCP-Ba compromised the wider silique of OE-TPD1 plants and inhibited the morphology of OE-TPD1 siliques to the size observed in the wild type. A total of 258 CRPs were identified with the bioinformatic analysis in Arabidopsis, Brassica napus, Glycine max, Oryza sativa, Sorghum bicolor, and Zea mays. Based on the evolutionary tree classification, all CRP members can be categorized into five subgroups. Notably, 107 CRP genes were predicted to exhibit abundant expression in flowers and fruits. Most cysteine-rich peptides exhibited high expression levels in Arabidopsis and Brassica napus. These findings suggested the involvement of the CRP AtPCP-Ba in the TPD1 signaling pathway, thereby regulating silique development in Arabidopsis.

7.
Adv Mater ; : e2407859, 2024 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-39223852

RESUMO

Temperature and pulse waves are two fundamental indicators of body health. Specifically, thermoresistive flexible temperature sensors are one of the most applied sensors. However, they suffer from poor reproducibility of resistivity; and decoupling temperature from pressure/strain is still challenging. Besides, autonomous thermoregulation by wearable sensory systems is in high demand, but conventional commercial apparatuses are cumbersome and not suitable for long-term portable use. Here, a material-design strategy is developed to overcome the problem of poor reproducibility of resistivity by tuning the thermal expansion coefficient to nearly zero, precluding the detriment caused by shape expansion/shrinkage with temperature variation and achieving high reproducibility. The strategy also obtains more reliable sensitivity and higher stability, and the designed thermoresistive fiber has strain-insensitive sensing performance and fast response/recovery time. A smart textile woven by the thermoresistive fiber can decouple temperature and pulse without crosstalk; and a flexible wireless closed-loop system comprising the smart textile, a heating textile, a flexible diminutive control patch, and a smartphone is designed and constructed to monitor health status in real-time and autonomously regulate body temperature. This work offers a new route to circumvent temperature-sensitive effects for flexible sensors and new insights for personalized thermoregulation.

8.
ACS Omega ; 9(37): 38846-38854, 2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39310152

RESUMO

Matrine and oxymatrine are mainly obtained from Sophora flavescens using the high-temperature and prolonged solvent extraction methods currently employed in industries. In this study, an ultrafast and highly efficient method for extracting matrine and oxymatrine from S. flavescens at room temperature using laser technology, specifically, laser extraction, was demonstrated. The laser extraction rates for matrine and oxymatrine from S. flavescens at room temperature for 1 min were 266.40 and 936.80 mg(g·h)-1, respectively. These rates were 1400 times higher than those achieved with conventional solvent extraction. These results mean that 1 min of laser extraction is equivalent to 24 h of solvent extraction. The reason for such a high efficiency is that laser-induced cavitation can accelerate the rapid release of alkaloid molecules in plant cells. Mass spectrum, nuclear magnetic resonance, and Fourier-transform infrared spectrum analyses of the extracted matrine and oxymatrine compounds confirmed that they are the same as the products of solvent extraction. Furthermore, it was found that the anticancer activity of laser-extracted compounds is slightly better than that of conventionally solvent-extracted ones, likely due to the slight change in the microstructure or conformation of these compounds under laser irradiation. These findings demonstrated that the laser extraction method was ultrafast and highly efficient, unveiling a novel approach to alkaloid extraction. This discovery will have significant implications for the extraction and utilization of alkaloids from plants.

9.
Inorg Chem ; 63(38): 17651-17661, 2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-39230943

RESUMO

Currently, there is not much success in solving the molecular and crystal structures of long-chain metal alkanethiolate complexes [M(SCnH2n+1)m] at the atomic level. Taking Sb(SC16H33)3 (1) as an example, we herein disclose the structural characteristics of long-chain trivalent antimony(III) alkanethiolates Sb(SCnH2n+1)3 (n ≥ 12) by single-crystal X-ray crystallography. Specifically, the Sb atom is three-coordinated by alkanethiolate ligands and a slightly distorted triangular pyramid SbS3 core is formed owing to the unique intramolecular stereochemistry of three alkyl chains, namely, two of them almost parallel aligning and the third chain extending alone around the SbS3 core. We further determine the conformation, spatial orientation and packing density of alkyl chains in 1 along with a comparison to those in other long-chain crystalline systems, and reveal the roles of intermolecular van der Waals and Sb···S secondary interactions in molecular self-assembly, which enables 1 to be a layer-structured molecular crystal with a monoclinic P21/c unit cell. The band structures and the atomic orbital contributions to the valence band maximum and conduction band minimum for 1 have also been evaluated by DFT calculations and rationally correlated with its optical absorption property. This study will help understand and discover new structures and structure-property relations of long-chain chemical systems.

10.
Artigo em Inglês | MEDLINE | ID: mdl-39299550

RESUMO

PURPOSE: To compare the outcomes of transarterial chemoembolization (TACE) alone with those of TACE combined with external beam radiation therapy (EBRT) in patients with hepatocellular carcinoma (HCC) in a multicenter randomized study. METHODS AND MATERIALS: From 2017 to 2022, 74 HCC patients with tumors confined to the liver without vascular invasion were treated with either TACE only (TACE group, 39 patients) or TACE combined with EBRT (TACE + EBRT group, 35 patients). The primary outcome measured was overall survival (OS). Secondary outcomes included progression-free survival (PFS), local tumor control, and the assessment of treatment-related toxicity. RESULTS: Due to slow accrual, the trial was closed prematurely after enrolling 74 patients. All patients received 2 cycles of TACE before randomization. The TACE and TACE + EBRT groups showed comparable patient and tumor characteristics. The TACE group underwent a median of 3 TACE cycles, and the TACE + EBRT group received 2 cycles of TACE, and a median of 5500 cGy in 15 fractions. For the TACE group, the median local control (LC) duration was 13.1 months, whereas for the TACE + EBRT group, the median LC was not achieved (P < .001). The PFS was recorded at 11.6 months in the TACE group compared with 15.4 months in the TACE + EBRT group (P = .072). The median OS reached 36.8 months for the TACE group and extended to 47.1 months for the TACE + EBRT group (P = .654). The incidence of toxicity was comparable between both groups. CONCLUSIONS: Although the number of patients enrolled in this clinical trial did not meet expectations. TACE combined with EBRT was shown to be more effective than TACE alone in improving LC without increasing toxicity, whereas PFS and OS were slightly improved. TACE + EBRT can be used as a standard treatment option for patients with inoperable but confined intrahepatic HCC.

11.
Discov Oncol ; 15(1): 345, 2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-39133261

RESUMO

BACKGROUND: Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide, characterized by high rates of angiogenesis and immune evasion. Paraspeckle genes, involved in gene regulation and RNA metabolism, have recently been linked to tumor progression. This study aims to elucidate the relationship between paraspeckle genes and HCC prognosis, focusing on SFPQ, DDX39B, and UBAP2. METHODS: We analyzed HCC (LIHC) and prostate cancer (PRAD) samples from the TCGA database to explore the correlation between paraspeckle genes and angiogenesis. We conducted unsupervised clustering, risk scoring, and survival analysis to identify distinct patient groups and their clinical outcomes. Gene expression data were used to perform differential analysis and Gene Ontology (GO) enrichment. RESULTS: Our analysis identified significant correlations between paraspeckle genes and angiogenesis across multiple cancer types. Elevated expression levels of SFPQ, DDX39B, and UBAP2 were associated with poor prognosis in HCC patients, and all of them has statistical significance. Unsupervised clustering of HCC samples based on paraspeckle gene expression revealed two distinct clusters, with high-risk patients exhibiting stronger immune suppression and tumor immune evasion. GO enrichment highlighted critical pathways related to angiogenesis and immune regulation. Additionally, a risk scoring model based on these genes effectively distinguished high-risk and low-risk patient groups, providing valuable prognostic insights. CONCLUSION: This study demonstrates that SFPQ, DDX39B, and UBAP2 are significantly associated with poor prognosis in HCC, likely due to their roles in promoting angiogenesis and immune suppression. These findings highlight the potential of paraspeckle genes as prognostic biomarkers and therapeutic targets, offering new avenues for personalized treatment strategies in HCC. Further research into their functional mechanisms and clinical applicability is crucial for advancing HCC treatment and improving patient outcomes.

12.
Int J Med Mushrooms ; 26(10): 19-40, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39171629

RESUMO

Cordyceps militaris, Chinese traditional medicinal fungus, has many bioactive properties. Cordycepin (3'-deoxyadenosine) is a major bioactive component of C. militaris. Various methods can significantly elevate cordycepin production, which suggests a diverse set of metabolic regulatory mechanisms. Thus, we aimed to identify transcription factors that regulate cordycepin biosynthesis pathways. Transcriptome analysis of wild-type C. militaris, C. militaris GYS60, a cordycepin high-producing strain, and C. militaris GYS80, a low-producing strain, were used to measure expression and function of genes related to cordycepin biosynthesis. The transcriptome expression data were confirmed by quantitative real-time polymerase chain reaction. We identified 155 relevant transcription factors in 19 families that included Fork head/winged helix factors, other C4 zinc finger-type factors, C2H2 zinc finger factors, tryptophan cluster factors, nuclear receptors with C4 zinc fingers, homeodomain factors, and Rel homology region factors. Energy generation and amino acid conversion pathways were activated in GYS60 so that abundance of cordycepin precursors was increased. Genes and transcription factors for rate-limiting enzymes in these pathways were identified. Overexpression of two key transcription factors, Kruppel-like factor 4 (Klf4) and Retinoid X receptor alpha (Rxra), promoted high cordycepin production in GYS60. In GYS60, Klf4 and Rxra were responsible for upregulation of genes in cordycepin biosynthesis, namely an oxidoreductase, 3',5'-cyclic AMP phosphodiesterase, a transferase, and adenylate cyclase. Upregulation of these genes increased 3'-AMP content, thereby elevating cordycepin synthesis.


Assuntos
Cordyceps , Desoxiadenosinas , Fator 4 Semelhante a Kruppel , Desoxiadenosinas/biossíntese , Cordyceps/genética , Cordyceps/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Regulação Fúngica da Expressão Gênica , Perfilação da Expressão Gênica , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Vias Biossintéticas
13.
iScience ; 27(8): 110462, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39104405

RESUMO

Colorectal cancer (CRC) is one of the most common gastrointestinal tumors. Src homology-2 domain-containing protein tyrosine phosphatase-2 (SHP2) mutations occur in human solid tumors, including CRC. However, the function and underlying mechanism in CRC have not been well characterized. We demonstrated that the SHP2D61Y and SHP2E76K mutations occurred in CRC tissues, and these mutations promoted CRC cell proliferation, migration/invasion, and reduced CDDP-induced cell apoptosis in vitro and in vivo. Mechanistically, SHP2D61Y and SHP2E76K promote glycolysis by accelerating pyruvate kinase M2 (PKM2) nuclear translocation through mechanism beyond ERK activation. PKM2-IN-1 attenuates PKM2-dependent glycolysis and reduce glucose uptake, lactate production, and ATP levels promoted by SHP2D61Y and SHP2E76K in CRC cells. Furthermore, PKM2 upregulates heterogeneous nuclear ribonucleoprotein K (hnRNPK) expression and increases CRC cell proliferation and migration/invasion via regulating hnRNPK ubiquitination. These findings provide evidence that SHP2D61Y and SHP2E76K regulate CDDP-induced apoptosis, glucose metabolism, and CRC migration/invasion through PKM2 nuclear translocation and PKM2/hnRNPK signaling.

14.
Nanoscale Horiz ; 9(10): 1599-1629, 2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-39046195

RESUMO

With distinctive advantages spanning excellent flexibility, rich physical properties, strong electrostatic tunability, dangling-bond-free surface, and ease of integration, 2D layered materials (2DLMs) have demonstrated tremendous potential for photodetection. However, to date, most of the research enthusiasm has been merely focused on developing novel prototype devices. In the past few years, researchers have also been devoted to developing various downstream applications based on 2DLM photodetectors to contribute to promoting them from fundamental research to practical commercialization, and extensive accomplishments have been realized. In spite of the remarkable advancements, these fascinating research findings are relatively scattered. To date, there is still a lack of a systematic and profound summarization regarding this fast-evolving domain. This is not beneficial to researchers, especially researchers just entering this research field, who want to have a quick, timely, and comprehensive inspection of this fascinating domain. To address this issue, in this review, the emerging downstream applications of 2DLM photodetectors in extensive fields, including imaging, health monitoring, target tracking, optoelectronic logic operation, ultraviolet monitoring, optical communications, automatic driving, and acoustic signal detection, have been systematically summarized, with the focus on the underlying working mechanisms. At the end, the ongoing challenges of this rapidly progressing domain are identified, and the potential schemes to address them are envisioned, which aim at navigating the future exploration as well as fully exerting the pivotal roles of 2DLMs towards the practical optoelectronic industry.

15.
J Colloid Interface Sci ; 672: 126-132, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-38833732

RESUMO

Despite the excellent photocatalytic activity under visible light, graphitic carbon nitride (g-C3N4) exhibits a high overpotential for hydrogen evolution. To address this issue, cocatalysts have been utilized to modify g-C3N4. However, the use of high-performance cocatalysts typically involves noble metals such as platinum and palladium, which are cost-prohibitive for practical applications. Therefore, the development of efficient and cost-effective cocatalysts is crucial for advancing photocatalysis. In this study, we synthesized a new Ni-based cocatalyst, nickel thiocarbonate (NiCS3), to enhance the photocatalytic hydrogen evolution reaction (HER) on g-C3N4. The NiCS3/g-C3N4 composite demonstrated a significantly increased hydrogen evolution rate of 951 µmol·h-1·g-1 under visible light, representing more than a 105-fold improvement compared to pure g-C3N4. Theoretical calculations suggested that the enhanced performance in photocatalytic hydrogen production can be attributed to the generation of a built-in electric field within the composite, facilitating efficient charge carrier separation and migration. Additionally, the C site in NiCS3 provides a favorable Gibbs free energy of adsorbed H* (ΔGH∗). This work underscores the potential of NiCS3 as a viable alternative to precious metals in photocatalytic hydrogen production using g-C3N4.

16.
Opt Express ; 32(9): 16307-16318, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38859261

RESUMO

Aiming at the difficulty of traditional chaotic-shift-keying (CSK) systems in resisting return map attacks, we propose an optical chaotic communication system based on time-delayed shift keying and common-signal-induced synchronization. This scheme combines amplified spontaneous emission (ASE) noise, phase modulator (PM), and fiber Bragg grating (FBG) to achieve dual masking in both intensity and phase fields, achieving 10Gb/s information transmission. A common-signal-induced method is used to achieve the synchronization of the system. Moreover, by shifting the time delay as the message-feeding method, the return map attack is effectively resisted, to prevent the amplitude and frequency information of the chaotic attractor from being exposed. In terms of confidentiality and communication performance, this scheme demonstrates good performance of time delay signatures (TDSs) concealment and long-distance transmission capability. In addition, this scheme maintains high sensitivity to key parameters and achieves better confidentiality while increasing the key space.

17.
PLoS One ; 19(6): e0305424, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38865366

RESUMO

Urban traffic flow prediction plays a crucial role in intelligent transportation systems (ITS), which can enhance traffic efficiency and ensure public safety. However, predicting urban traffic flow faces numerous challenges, such as intricate temporal dependencies, spatial correlations, and the influence of external factors. Existing research methods cannot fully capture the complex spatio-temporal dependence of traffic flow. Inspired by video analysis in computer vision, we represent traffic flow as traffic frames and propose an end-to-end urban traffic flow prediction model named Spatio-temporal Decoupled 3D DenseNet with Attention ResNet (ST-D3DDARN). Specifically, this model extracts multi-source traffic flow features through closeness, period, trend, and external factor branches. Subsequently, it dynamically establishes global spatio-temporal correlations by integrating spatial self-attention and coordinate attention in a residual network, accurately predicting the inflow and outflow of traffic throughout the city. In order to evaluate the effectiveness of the ST-D3DDARN model, experiments are carried out on two publicly available real-world datasets. The results indicate that ST-D3DDARN outperforms existing models in terms of single-step prediction, multi-step prediction, and efficiency.


Assuntos
Cidades , Meios de Transporte , Humanos , Análise Espaço-Temporal , Modelos Teóricos , Algoritmos
18.
Small ; 20(40): e2403005, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38847065

RESUMO

By combining Pd with 2D layered crystal CuInP2S6 (CIPS) via laser irradiation in liquids, low-loading Pd@CIPS core-shell nanospheres are fabricated as an efficient and robust electrocatalysts for HER in both alkaline and acidic media under large current density (⩾1000 mA cm-2). Pd@CIPS core-shell nanosphere has two structural features, i) the out-shell is the nanocomposite of PdHx and PdInHx, and ii) there is a kind of dendritic structure on the surface of nanospheres, while the dendritic structure porvides good gas desorption pathway and cause the Pd@CIPS system to maintain higher HER activity and stability than that of commercial Pt/C under large current densities. Pd@CIPS exhibits very low overpotentials of -218 and -313 mV for the large current density of 1000 mA cm-2, and has a small Tafel slope of 29 and 63 mV dec-1 in 0.5 m H2SO4 and 1 m KOH condition, respectively. Meanwhile, Pd@CIPS has an excellent stability under -10 and -500 mA cm-2 current densities and 50 000 cycles cyclic voltammetry tests in 0.5 m H2SO4 and 1 m KOH, respectively, which being much superior to that of commercial Pt/C. Density functional theory (DFT) reveals that engineering electronic structure of PdHx and PdInHx nanostructure can strongly weaken the Pd─H bonding.

19.
J Am Chem Soc ; 146(21): 14765-14775, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38752294

RESUMO

Ultrafast N2 fixation reactions are quite challenging. Currently used methods for N2 fixation are limited, and strong dinitrogen bonds usually need to be activated via extreme temperature or pressure or by the use of an energy-consuming process with sophisticated catalysts. Herein, we report a novel laser-based chemical method for N2 fixation under ambient conditions without catalysts, this method is called laser bubbling in liquids (LBL), and it directly activates N2 in water (H2O) and efficiently converts N2 into valuable NH3 (max: 4.2 mmol h-1) and NO3- (0.17 mmol h-1). Remarkably, the highest yields of NH3 and NO3- are 4 orders of magnitude greater than the best values for electrocatalysis reported to date. Notably, we further validate the experimental mechanism by using optical emission spectroscopy to detect the production of intermediate plasma and by employing isotope tracing. We also establish that an extremely high-temperature environment far from thermodynamic equilibrium inside a laser-induced bubble and the kinetic process of rapid quenching of bubbles is crucial for N2 activation and fixation to generate NH3 and NOx via LBL. Based on these results, it is shown that LBL is a simple, safe, efficient, green, and sustainable technology that enables the rapid conversion of the renewable feedstocks H2O and N2 to NH3 and NO3-, facilitating new prospects for chemical N2 fixation.

20.
Inorg Chem ; 63(14): 6465-6473, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38528435

RESUMO

Two-dimensional inorganic-organic hybrid layered semiconductors are actively studied because of their naturally formed multiquantum well (MQW) structures and associated optical, photoelectric, and quantum optics characteristics. Silver benzeneselenolate (AgSePh, Ph = C6H5) is a new member of such hybrid layered materials, but has not fully been exploited. Herein, we present a quasi-solution method to prepare high quality free-standing AgSePh flake-like microcrystals by reacting diphenyl diselenide (Ph2Se2) with silver nanoparticles. The resultant AgSePh microflakes exhibit room-temperature (RT) resolvable MQW-induced quasi-particle quantization and interesting optical properties, such as three distinct excitonic resonance absorptions X1 (2.67 eV), X2 (2.71 eV), and X3 (2.83 eV) in the visible region, strong narrow-line width blue photoluminescence at ∼2.64 eV (470 nm) from the radiative recombination of the X1 exciton state, and a large exciton binding energy (∼0.35 eV). Furthermore, AgSePh microcrystals show high stability under water, oxygen, and heat environments, while above 220 °C, they will thermally decompose to silver and Ph2Se2 as evidenced by a combination of thermogravimetry and differential scanning calorimetry and pyrolysis-coupled gas chromatography-mass spectrometry studies. Finally, a comparison is extended between AgSePh and other metal benzeneselenolates, benzenethiolates, and alkanethiolates to clarify differences in their solubility, decomposition/melting temperature, and pyrolytic products.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA