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Despite the potential of deep learning (DL)-based methods in substituting CT-based PET attenuation and scatter correction for CT-free PET imaging, a critical bottleneck is their limited capability in handling large heterogeneity of tracers and scanners of PET imaging. This study employs a simple way to integrate domain knowledge in DL for CT-free PET imaging. In contrast to conventional direct DL methods, we simplify the complex problem by a domain decomposition so that the learning of anatomy-dependent attenuation correction can be achieved robustly in a low-frequency domain while the original anatomy-independent high-frequency texture can be preserved during the processing. Even with the training from one tracer on one scanner, the effectiveness and robustness of our proposed approach are confirmed in tests of various external imaging tracers on different scanners. The robust, generalizable, and transparent DL development may enhance the potential of clinical translation.

● Gasification of cow dung was evaluated using Aspen Plus software.● Optimum reaction conditions were utilized to maximize hydrogen production.● Steam gasification can effectively increase hydrogen production.● Optimum hydrogen production was achieved at 800 °C and steam/biomass of 1.5 and 0.1 MPa. In this study, a biomass gasification model was developed and simulated based on Gibbs free energy minimization by using software Aspen Plus. Two reactors, RYIELD and RGIBBS, were moslty used. The biomass feedstock used was cow dung. The model was validated. The composition, H2/CO ratio and low heating value (LHV) of the resulting synthetic gas (also known as syngas) was estimated by changing the operating parameters of gasification temperatures, steam and biomass ratios and pressures. Simulation results showed that increased gasification temperature helped to elevate H2 and CO content and H2 peaked at 900 °C. When steam increased as the gasification agent, H2 production increased. However, the steam/biomass (S/B) ratio negatively affected CO and CH4, resulting in lower LHV. The optimal S/B ratio was 1.5. An increase in pressure lead to a decrease in H2 and CO content, so the optimal pressure for gasification was 0.1 MPa.

Marine DC power grid typically sustains high current when shorted and its electric characteristics are extremely susceptible to influence by the stray parameters. Given the limitations of cabin space, it is necessary for the bus-tie switch of the DC grid to be miniaturized and in a symmetrical topology while the same level of fault shutdown protection performance is maintained. To this end, this paper presents the rule that how support capacitors and busbar's stray parameters impact short-circuit current, which was analyzed through a combination of simulation and testing at multiple operating points of a typical DC power grid. Specifically, to ensure the safety of devices, breaking time of the solid-state circuit breaker should not exceed 200 μs, and addressing the transient overvoltage suppression in case of bus- tie switch breaking is identified as a key technical issue. Based on the analysis results, it proposes a solid-state circuit breaker with a mirror-symmetrical bus-tie switch topology suitable for marine application scenarios and with the optimized performance based on simulation, to integrate the bus-tie switch and chopper multiplexing as a solution for voltage oscillation upon the bus-tie switch breaking-off. Based on the practical short-circuit tests, it is verified that the designed bus-tie switch is capable of meeting continuous DC power supply conditions on the normal side DC power grid when the busbar and branch are short-circuited. The onboard test results show that the solid-state circuit breaker can achieve a breaking-off capacity in the order of 100 μs, the optimized design of bus-tie switch topology meets the short-circuit protection requirements of marine DC power grid, and the delay for the bus-tie switch to break-off in case of short-circuit fault can mitigate breaking overvoltage fluctuation, thus better guaranteeing system safety.

Due to the strictly restricted free area, vehicles have difficulties to pass through mine narrow corridors. To solve this problem, this paper presents a trajectory planning method based on optimal control. Narrow corridor model and vehicle single-track kinematics model are adopted to construct the trajectory planning model based on optimal control with an approximate space-discretization strategy considering factors like vehicle passage time, vehicle-boundary collision and vehicle actuator range. By vehicle kinematics integral, the control variable sequence solved by the above trajectory planning model leads to an initial optimal trajectory. Taking the discretization impact on trajectory continuity into account, the final target trajectory is formed after smooth the initial optimal trajectory by quadratic programming. Simulation results show that the trajectory generated by the proposed method is effective in narrow corridor scene, and the generated trajectory is continuous and smooth. Compared with the baseline method, the average maximum curvature reduces from 0.094 m-1 to 0.040 m-1 and the average passing time reduces from 6.18 s to 4.80 s in evaluate scenarios.

Escalating global climate change and the intensification of urban heatwaves have led to an increase in summer air conditioning cooling energy consumption. This phenomenon is particularly critical in tropical regions, as it may trigger an energy crisis. The rational setting of indoor thermal design parameters can help conserve energy to the maximum extent while ensuring thermal comfort for occupants. This study selected Haikou City, a unique tropical city in China, as the research location. Indoor environment measurements and a questionnaire survey were conducted with participants, and the outdoor thermal environment sensitivity, population attributes and differences in thermal sensation, thermal neutral temperature, and comfort range were calculated and analyzed. The following results were obtained. Based on the overall population, long-term residence, and temporary residence classification, the indoor thermal comfort needs of residents in tropical cities in Haikou were effectively identified. The actual thermal neutral temperature of the overall population is 25.7 °C, and 90% of the acceptable thermal comfort temperature range is 23.2 °C–28.0 °C. The actual thermal neutral temperature of the regular residents is 27.3 °C, and 90% of the acceptable thermal comfort temperature range is 23.3 °C–31.4 °C. The actual thermal neutral temperature of the temporary population is 25.5 °C, and 90% of the acceptable thermal comfort temperature range is 23.0 °C–28.0 °C. These research results have an important reference value for improving the setting of the temperature of air conditioning in tropical areas in summer and further reducing energy consumption, which is conducive to sustainable development. [ABSTRACT FROM AUTHOR]

Objective To investigate the expression of heparanase-2 (HPSE2) in gastric cancer tissues, and explore its effect on the survival and prognosis of the cancer and invasion and migration of the cancer cells. Methods Immunohistochemical staining of HPSE2 was performed on gastric cancer tissue chip to examine the expression level of HPSE2 in gastric cancer and paracancerous tissues. The correlation of HPSE2 expression level with clinical features, survival, prognosis and prognostic factors were analyzed. The lentival vectors of HPSE2 overexpression were constructed, and then transfected in gastric cancer cell lines SGC7901 and MKN28. The effect of HPSE2 overexpression on invasion and migration of gastric cancer cells were detected using Transwell analysis. Results The mean pathological score of HPSE2 was 4.56 in gastric cancer tissue, and 7.18 in paracancer tissues, showing that the expression was significantly lower in gastric cancer than paracancer tissues (P < 0.05). The expression level of HPSE2 was closely correlated with the tumor size, lymph node metastasis, and clinical staging. The patients with higher HPSE2 expression had obviously shorter median survival time and cumulative survival rate than those with lower expression (P < 0.05). Cox proportional risk model showed that clinical stage, tumor size and HPSE2 protein expression were risk factors for prognosis of gastric cancer patients (P < 0.05). Overexpression of HPSE2 could remarkably inhibit the invasion and migration of gastric cancer cells. Conclusion HPSE2 is lowly expressed in gastric cancer tissues, and is associated with the tumor size, lymph node metastasis, survival and prognosis of gastric cancer. Overexpression of HPSE2 could inhibit the invasion and migration of gastric cancer cells.

Severe regional haze events, which are characterized by exceedingly high levels of fine particulate matter (PM), occur frequently in many developing countries (such as China and India), with profound implications for human health, weather, and climate. The occurrence of the haze extremes involves a complex interplay between primary emissions, secondary formation, and conducive meteorological conditions, and the relative contributions of the various processes remains unclear. Here we investigated severe regional haze episodes in 2013 over the Northern China Plain (NCP), by evaluating the PM production and the interactions between elevated PM and the planetary boundary layer (PBL). Analysis of the ground-based measurements and satellite observations of PM properties shows nearly synchronized temporal PM variations among the three megacities (Beijing, Baoding, and Shijiazhuang) in this region and a coincidence of the aerosol optical depth (AOD) hotspots with the three megacities during the polluted period. During the clean-to-hazy transition, the measured oxygenated organic aerosol concentration ([OOA]) well correlates with the odd-oxygen concentration ([Ox] = [O3] + [NO2]), and the mean [OOA]/[Ox] ratio in Beijing is much larger than those in other megacities (such as Mexico City and Houston), indicating highly efficient photochemical activity. Simulations using the Weather Research and Forecasting (WRF) model coupled with an explicit aerosol radiative module reveal that strong aerosol-PBL interaction during the polluted period results in a suppressed and stabilized PBL and elevated humidity, triggering a positive feedback to amplify the haze severity at the ground level. Model sensitivity study illustrates the importance of black carbon (BC) in the haze-PBL interaction and the aerosol regional climatic effect, contributing to more than 30% of the PBL collapse and about half of the positive radiative forcing on the top of the atmosphere. Overall, severe regional haze exhibits strong negative radiative forcing (cooling) of -63 to -88 W m-2 at the surface and strong positive radiative forcing (warming) of 57 to 82 W m-2 in the atmosphere, with a slightly negative net radiative forcing of about -6 W m-2 on the top of the atmosphere. Our work establishes a synthetic view for the dominant regional features during severe haze events, unraveling rapid in-situ PM production and inefficient transport, both of which are amplified by atmospheric stagnation. On the other hand, regional transport sufficiently disperses gaseous aerosol precursors (e.g., sulfur dioxide, nitrogen oxides, volatile organic compounds, and ammonia) during the clean period, which subsequently result in rapid in-situ PM production via photochemistry during the transition period and via multiphase chemistry during the polluted period. Our findings highlight the co-benefits for reduction in BC emissions, which not only improve local and regional air quality by minimizing air stagnation but also mitigate the global warming by alleviating the positive direct radiative forcing. [ABSTRACT FROM AUTHOR]