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The data of neutron capture reaction cross section are very important basic data in the research fields of advanced nuclear energy development and nuclear astrophysics. In order to accurately measure the cross section of neutron capture reaction in keV energy region and fill the gap of domestic experimental data. Key laboratory of nuclear data at China Academy of Atomic Energy has built the first gamma-ray total absorption BaF2 facility in China based on back-streaming white neutron source at China spallation neutron source. The detection efficiency curve of gamma-ray is an important experimental parameter. Using the combination of experiment and simulation, the experimental results obtained by measuring 137Cs and 60Co sources are in good agreement with the simulation results of MCNP and GEANT4, which verifies the reliability of detection efficiency curve calculated by simulation. It will be used in the on-line measurement experiment of neutron capture reaction cross section.

Natural disasters like hurricanes, wildfires, and floods pose immediate hazards. Such events often necessitate prompt emergency evacuations to save lives and reduce fatalities, injuries, and property damage. This study focuses on optimizing wildfire evacuations by analyzing the influence of different transportation infrastructures and the penetration of autonomous vehicles (AVs) on a historical wildfire event. The methodology involves modeling various evacuation scenarios and incorporating different intersection traffic controls such as roundabouts and stop signs and an evacuation strategy like lane reversal with various AV penetration rates. The analysis results demonstrate that specific interventions on evacuation routes can significantly reduce travel times during evacuations. Additionally, a comparative analysis across different scenarios shows a promising improvement in travel time with a higher level of AV penetration. These findings advocate for the integration of autonomous technologies as a crucial component of future emergency response strategies, demonstrating the potential for broader applications in disaster management. Future studies can expand on these findings by examining the broader implications of integrating AVs in emergency evacuations. [ABSTRACT FROM AUTHOR]

Open caisson foundations are often used in large-span bridge construction because of their advantageous, and an open caisson foundation gradually sinks to a predetermined position via earth excavation. Excessive sinking speed may result in various construction risks (e.g. inclination and structural damage of the open caisson). To prevent these risks, it is important to analyse the sinking situation of the foundation and predict the sinking speed during the sinking process. A sinking speed prediction model is proposed based on the gradient boosting decision tree (GBDT) algorithm, and the model can extract the data features of the structural stress monitoring data to predict the sinking speed of open caissons. Taking the supersized open caisson foundation in the Changtai Yangtze River Bridge Project as a case study, the proposed model was validated by using the monitoring data of this foundation. The validation results of this project indicate that the proposed model has high prediction accuracy, short time consumption, a good prediction effect and high practicability. Based on the model's prediction, an earth excavation scheme can be flexibly adjusted to prevent the potential construction risks of open caissons caused by excessive sinking speed. [ABSTRACT FROM AUTHOR]

Cholesterol metabolism is vital for multiple cancer progression, while how cholesterol affects lung, a low-cholesterol tissue, for cancer metastasis and the underlying mechanism remain unclear. In this study, we found that metastatic lung adenocarcinoma cells acquire cellular dehydrocholesterol and cholesterol by endogenous cholesterol biosynthesis, instead of uptake upon cholesterol treatment. Besides, we demonstrated that exogenous cholesterol functions as signaling molecule to induce FOXA3, a key transcription factor for lipid metabolism via GLI2. Subsequently, ChIP-seq analysis and molecular studies revealed that FOXA3 transcriptionally activated Hmgcs1, an essential enzyme of cholesterol biosynthesis, to induce endogenous dehydrocholesterol and cholesterol level for membrane composition change and cell migration. Conversely, FOXA3 knockdown or knockout blocked cholesterol biosynthesis and lung adenocarcinoma metastasis in mice. In addition, the potent FOXA3 inhibitor magnolol suppressed metastatic gene programs in lung adenocarcinoma patient-derived organoids (PDOs). Altogether, our findings shed light onto unique cholesterol metabolism and FOXA3 contribution to lung adenocarcinoma metastasis. Cholesterol is important for cancer progression, yet its levels are low in the lung. How is this overcome during lung cancer? This study shows that exogenous cholesterol can be sensed by lung adenocarcinoma cells, leading to activation of de novo cholesterol biosynthesis through a GLI2-FOXA3-HMGCS1 transcriptional axis, thereby promoting cancer progression. [ABSTRACT FROM AUTHOR]

Methoxy poly(ethylene glycol)-block-poly(L-lactide) (MPEG-b-PLLA) has a wide range of applications in pharmaceuticals and biology, and its structure and morphology have been thoroughly studied. In the experiment, we synthesized MPEG-b-PLLA with different block lengths using the principle of ring-opening polymerization by controlling the amount of lactic acid added. The thermodynamic properties of copolymers and the crystallization properties of blends were studied separately. The crystallization kinetics of PDLA/MPEG-b-PLA and PLLA/MPEG-b-PLA composite films were studied using differential scanning calorimetry (DSC). The results indicate that the crystallization kinetics of composite films are closely related to the amount of block addition. The crystallinity of the sample first increases and then decreases with an increase in MPEG-b-PLLA content. These results were also confirmed in polarized optical microscope (POM) and wide-angle X-ray diffraction (WAXD) tests. When 3% MPEG-b-PLLA was added to the PDLA matrix, the blend exhibited the strongest crystallization performance. [ABSTRACT FROM AUTHOR]

BackgroundDue to the special physical properties of gallium, gallium is considered to be used as reactor coolant in the future. Therefore, a full set of gallium neutron data is needed. However, the experimental data of gallium in EXFOR (Nuclear reaction experimental data) database is rare. There are also some discrepancies among the evaluation data.PurposeThis study aims to obtain elastic scatting differential cross section for natural gallium at 8.0 MeV incident neutrons, so as to fill the blanks of the neutron data of gallium in the database and clarify the discrepancy among the evaluation data.MethodsFirst of all, the elastic scatting differential cross section data of natural gallium was measured at 21 different laboratory angles from 20° to 140° by using the multi-detector fast neutron time-of-flight (NTOF) spectrometer on HI-13 tandem acceleration at the China Institution of Atomic Energy (CIAE). The cross sections of gallium were normalized by n-p elastic scatting cross section, and the quality of data was improved by many methods applied to the measurement and data analysis. Then, the Monte-Carlo code STREUER was employed to rectify the neutron flux attenuation, multiple scattering and the finite geometry of the experiment. Finally, the measured TOF spectra were compared with that of simulated to determine experimental scatting differential cross section of 8.0 MeV incident neutrons.Results & ConclusionsThe results of cross section of secondary neutron for natural gallium are the world's first experimental data in the 8.0 MeV energy region. Compared with the evaluated data, the measured data is generally in good agreement with CENDL-3.2 data, but inconsistent with ENDF/B-8.0 data and JENDL-4.0 data. The divarication among these three data bases has been clarified by the experimental result, hence of great significance to data evaluation and theoretical model improvement.

The nanocomposite films from poly(lactic acid) (PLA) and palmitoylated cellulose nanocrystals (e‐CNCs) were characterized using different techniques. Raman spectra showed the formation of hydrogen bonding interactions between the PLA and the e‐CNCs. The proper amount (1.0 wt%) of the e‐CNCs led to the formation of greater amounts of smaller PLA spherulites and increased the PLA crystallinity in comparison with the neat PLA sample. The scanning and transmission electron microscopy images showed that 1.0 wt% of the e‐CNCs could uniformly be dispersed in the PLA matrix and that the nanocomposite exhibited some elasticity. The dynamic rheological properties showed the formation of interconnected networks in the PLA/e‐CNCs composite at 1.0 wt% of the e‐CNCs. The analysis of the mechanical performance of the ensuing nanocomposite showed a 74% increase in tensile strength, a 62.1% increase in Young's modulus, and a 68.4% increase in the elongation at the break after the incorporation of 1.0 wt% of the e‐CNCs into the PLA. Therefore, the palmitoylated CNCs were highly promising for the simultaneous enhancement in the strength and the toughness of PLA. Highlights: Reinforcement of poly(lactic acid) (PLA) by the palmitoylated CNCs.Simultaneous improvement in the strength and roughness of PLA sample.Entanglement and H‐bond between the palmitoylated CNCs and PLA molecular chain.More and smaller PLA crystals induced by the palmitoylated CNCs. [ABSTRACT FROM AUTHOR]

Over the past three decades, its excellent biodegradability and biocompatibility have enabled poly(lactide) (PLA) to be extensively explored as a replacement for oil-based thermoplastics in biomedical and industrial applications. However, PLA homopolymers have "facilitative" limitations such as low mechanical properties, low processing temperatures, slow recrystallization, and insufficient crystallinity, which have usually hindered commercial PLA in industrial and biomedical applications. The formation of stereo-complexation between enantiomeric poly(L -lactide) (PLLA) and poly(D -lactide) (PDLA) chains offers an effective approach to PLA-based engineering materials with improved properties. In this review, we have understandably summarized recent progress in improving the SC crystallization of PLA-based plastics into two aspects, i.e., enantiomeric PLA homopolymers, and enantiomeric PLA-based copolymers. One important point to be noted is that much emphasis is focused on improving SC crystallization by enhancing interactions in the enantiomeric PLA-based copolymers. There is an insightful discussion about the effect of enhanced SC crystallization as well as intermolecular interactions between PLLA and PDLA chains in various stereocomplexable systems. Most importantly, this review starts with the basic understanding of SC crystallization and further elaborates on the rational mechanism of enhanced SC crystallization to provide a broad idea for broadening the road toward PLA-based materials. [ABSTRACT FROM AUTHOR]