Search

Background: A dosimeter with high spatial and temporal resolution would be of significant interest for pencil beam scanning (PBS) proton beams' characterization, especially when facing small fields and beams with high temporal dynamics. Optical imaging of scintillators has potential in providing sub‐millimeter spatial resolution with pulse‐by‐pulse basis temporal resolution when the imaging system is capable of operating in synchrony with the beam‐producing accelerator. Purpose: We demonstrate the feasibility of imaging PBS proton beams as they pass through a plastic scintillator detector to simultaneously obtain multiple beam parameters, including proton range, pencil beam's widths at different depths, spot's size, and spot's position on a pulse‐by‐pulse basis with sub‐millimeter resolution. Materials and methods: A PBS synchrocyclotron was used for proton irradiation. A BC‐408 plastic scintillator block with 30 × 30 × 5 cm3 size, and another block with 30 × 30 × 0.5 cm3 size, positioned in an optically sealed housing, were used sequentially to measure the proton range, and spot size/location, respectively. A high‐speed complementary metal‐oxide‐semiconductor (CMOS) camera system synchronized with the accelerator's pulses through a gating module was used for imaging. Scintillation images, captured with the camera directly facing the 5‐cm‐thick scintillator, were corrected for background (BG), and ionization quenching of the scintillator to obtain the proton range. Spots' position and size were obtained from scintillation images of the 0.5‐cm‐thick scintillator when a 45° mirror was used to reflect the scintillation light toward the camera. Results: Scintillation images with 0.16 mm/pixel resolution corresponding to all proton pulses were captured. Pulse‐by‐pulse analysis showed that variations of the range, spots' position, and size were within ± 0.2% standard deviation of their average values. The absolute ranges were within ± 1 mm of their expected values. The average spot‐positions were mostly within ± 0.8 mm and spots' sigma agreed within 0.2 mm of the expected values. Conclusion: Scintillation‐imaging PBS beams with high‐spatiotemporal resolution is feasible and may help in efficient and cost‐effective acceptance testing and commissioning of existing and even emerging technologies such as FLASH, grid, mini‐beams, and so forth. [ABSTRACT FROM AUTHOR]

Given a graph G and an edge $ e\in E(G) $ e ∈ E (G) , let S be a vertex set of G. For any two vertices x, $ y\in S $ y ∈ S , if e belongs to all the shortest paths between x and y, then x and y can monitor the edge e. For each edge e of G, if there exists x and y in S such that x and y can monitor e, then the set S can be called a monitoring-edge-geodetic ( $ \operatorname {MEG} $ MEG for short) set of G. The $ \operatorname {MEG} $ MEG number, denoted by $ \operatorname {meg}(G) $ meg ⁡ (G) , is the size of the smallest $ \operatorname {MEG} $ MEG set of G. In this paper, we obtain the exact values of the $ \operatorname {MEG} $ MEG numbers for radix triangular mesh networks, Sierpiński graphs, Sierpiński gasket graphs and Sierpiński generalized graphs. [ABSTRACT FROM AUTHOR]

Design of flexible porous materials where the diffusion of guest molecules is regulated by the dynamics of contracted pore aperture is challenging. Here, a flexible porous self‐assembly consisting of 1D channels with dynamic bottleneck gates is reported. The dynamic pendant naphthimidazolylmethyl moieties at the channel necks provide kinetic gate function, that enables unusual adsorption for light hydrocarbons. The adsorption for CO2 is mainly dominated by thermodynamics with the uptakes decreasing with increasing temperature, whereas the adsorptions for larger hydrocarbons are controlled by both thermodynamics and kinetics resulting in an uptake maximum at a temperature threshold. Such an unusual adsorption enables temperature‐dependent separation of CO2 from the corresponding hydrocarbons. [ABSTRACT FROM AUTHOR]

Florida Bay, a large and shallow estuary, serves as a vital habitat for a diverse range of marine species and holds significant environmental, commercial, and recreational value. The Florida Bay ecosystem is under extensive stress due to decades of increased nutrient loads. Based on the Environmental Fluid Dynamics Code (EFDC), a hydrodynamic model was developed in this study. The model was calibrated with a comprehensive dataset, including measurements over 7 years from 34 tidal stations, 42 current stations, and 14 temperature and salinity stations. Key findings include the following: (1) the bay exhibits a shift in the tidal regime, transitioning from macro-tidal in the western region to micro-tidal in the central and eastern/northeast regions; (2) local winds and the subtidal variations from the coastal ocean are the primary drivers for the hydrodynamic processes in the eastern and central regions; (3) salinity changes in the bay are primarily controlled by three processes: the net supply of freshwater, the processes that drive mixing within the estuary (e.g., wind, topography, currents), and the exchange of salinity with the coastal ocean. This hydrodynamic model is essential for providing a comprehensive tool to address environmental challenges and sustain the bay's ecosystem health. [ABSTRACT FROM AUTHOR]

The chalcopyrite compound CuGa(In)Te2 has garnered significant attention due to its safe elemental composition and high thermoelectric potential. Optimizing the carrier concentration and reducing the lattice thermal conductivity of CuGa(In)Te2 can significantly enhance its thermoelectric performance. In this mini-review, we analyze the electronic and phonon structures of CuGa(In)Te2, summarize and categorize the representative methods employed in recent years to improve its thermoelectric performance. Our analysis reveals that reducing thermal conductivity has a more significant impact on enhancing the ZT value of CuGa(In)Te2 compared to increasing the power factor. In conclusion, we outline potential challenges and provide a brief outlook, offering valuable insights into the design of CuGa(In)Te2 chalcopyrite compounds as high-performance thermoelectric materials. [ABSTRACT FROM AUTHOR]

Background: Previous studies documented that heparin can inhibit the invasion and metastasis of tumors, but its role on outcomes in patients with solid malignancy complicated sepsis remains unclear. Methods: A retrospective cohort study was conducted in critically ill patients with solid malignancy associated sepsis from the Medical Information Mart for Intensive Care (MIMIC)-IV database. The primary endpoint was intensive care unit (ICU) mortality, secondary outcomes were thrombosis and hospital mortality. Propensity score matching (PSM), marginal structural Cox model (MSCM), cox proportional hazards model, stratification analysis and E-value were used to account for baseline differences, time-varying confounding and unmeasured variables. Results: A total of 1,512 patients with solid malignancy complicated sepsis were enrolled, of which 683 in the heparin group with intensive care unit mortality, thrombosis rate and hospital mortality were 9.7%, 5.4%, 16.1%, and 829 in the nonheparin group with ICU mortality, thrombosis rate and hospital mortality were 14.6%, 12.5%, 22.6%. Similar results were observed on outcomes for patients with PSM (ICU mortality hazard ratio [HR] 0.61, 95% confidence interval [CI] 0.41-0.92), thrombosis rate (HR 0.42, 95% confidence interval 0.26-0.68); hospital mortality HR 0.70, 95% CI 0.50-0.99). marginal structural Cox model further reinforced the efficacy of heparin in reducing ICU mortality (HR 0.48, 95% CI 0.34-0.68). Logistic regression and Cox regression model showed heparin use also markedly reduced thrombosis (HR 0.42; 95% CI 0.26-0.68; p < 0.001) and hospital mortality (HR 0.70; 95% CI 0.50-0.99; p = 0.043). Stratification analysis with the MSCM showed an effect only those with digestive system cancer (HR 0.33, 95% CI 0.16-0.69). [ABSTRACT FROM AUTHOR]

High-fat diet (HFD) can cause obesity, inducing dysregulation of the visceral adipose tissue (VAT). This study aimed to explore potential biological pathways and hub genes involved in obese VAT, and for that, bioinformatic analysis of multiple datasets was performed. The expression profiles (GSE30247, GSE167311 and GSE79434) were downloaded from Gene Expression Omnibus. Overlapping differentially expressed genes (ODEGs) between normal diet and HFD groups in GSE30247 and GSE167311 were selected to run protein–protein interaction network, GO and KEGG analysis. The hub genes in ODEGs were screened by Cytoscape software and further verified in GSE79434 and obese mouse model. A total of 747 ODEGs (599 up-regulated and 148 down-regulated) were screened, and the GO and KEGG analysis showed that the up-regulated ODEGs were significantly enriched in inflammatory response and extracellular matrix receptor interaction pathways. On the other hand, the down-regulated ODEGs were involved in metabolic pathways; however, there were no significant KEGG pathways. Furthermore, six hub genes, Mki67, Rac2, Itgb2, Emr1, Tyrobp and Csf1r were acquired. These pathways and genes were verified in GSE79434 and VAT of obese mice. This study revealed that HFD induced VAT expansion, inflammation and fibrosis, and the hub genes could be used as therapeutic biomarkers in obesity. [ABSTRACT FROM AUTHOR]

The distribution characteristics of tricyclic terpenes in biomarkers and their indicative significance for sedimentary environment and biological sources are discussed through the systematic geochemical analysis of source rocks and crude oil samples from Jurassic Da'anzhai Member in central Sichuan Basin by gas chromatography-mass spectrometry (GC-MS). The results show that the Pr/Ph ratios of source rocks and crude oil are medium level, with C19-C26 tricyclic terpenes showing the dominance of C21, low relative percentages of C19-20 and C23 contents, and C24TeT/C26TT value greater than 1, indicating that the water was shallow during the sedimentar/ period of Da'anzhai Member, and the biogenesis was mainly bacteria and algae, with rich mixed-source input of higher plants, which was formed in the weak reduction environment of freshwater lake facies. [ABSTRACT FROM AUTHOR]