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Objective To evaluate the impact of meningococcal vaccine immunization on the incidence of meningococcal meningitis, aiming to refine the local immunization strategies and programs. Methods Data on the reported incidence of meningococcal meningitis in Hebei province for 1970-2023 were collected, and interrupted time-series( ITS) analysis was used to quantitatively analyze the levels and slope change of the incidence of meningococcal meningitis before and after vaccine immunization and before and after inclusion in the Expanded Program on Immunization (EPI). Results The annual average reported incidences of meningococcal meningitis in Hebei province before vaccination (1970-1979), before (1980-2007) and after (2008-2023) the inclusion of the vaccine in the EPI were respectively 20.79 per 100 000, 1.66 per 100 000, and 0.018 per 100 000. The interrupted time-series analysis from 1970 to 2023 showed an initial meningitis incidence rate of 24.12 per 100 000 (t=9.86, P<0.05), with an average annual decrease of 1.07 per 100 000 (t=-2.42, P<0.05). After the introduction of the meningococcal vaccine in 1980, the incidence of meningococcal meningitis decreased quickly with an annual average decline of 18.39 per 100 000, showing a significant short-term intervention effect (t=-2.70, P<0.05); however, the rate of decrease slowed over the long term to 0.13 per 100 000, with the long-term intervention effect not being significant (P>0.05). And the incidence was significantly increased due to the outbreak (t=7.80, P<0.05). From 1980 to 2023, the initial level of incidence was 5.13 per 100 000 (t=8.70, P<0.05), and decreased by 0.23/100 000 per year on average (t=-6.42, P<0.05). After the inclusion of the vaccine in the EPI in 2008, the rate of decrease further slowed down to an average of 0.008 per 100,000 per year, with the long-term intervention effect being significant (t=2.50, P<0.05); the impact of epidemic outbreaks on incidence during this period was not statistically significant (P>0.05). Conclusions Meningococcal meningitis vaccination has led to a general downward trend in the incidence of meningitis in Hebei Province, and has flattened the trend of increased incidence caused by outbreaks. Therefore, long-term maintenance in immunization programs on the meningococcal meningitis is necessary. In addition, it is important to strengthen the monitoring of the distribution of epidemic serogroups in patients and healthy carriers, and to adjust immunization strategies timely based on changes in bacterial populations, selecting and promoting vaccines accordingly for the prevalent strains. [ABSTRACT FROM AUTHOR]

Developing cost-effective, active, and durable electrocatalysts is one of the most important issues for the commercialization of fuel cells. Ultrathin Pt-Mo-Ni nanowires (NWs) with a diameter of ~2.5 nm and lengths of up to several micrometers were synthesized via a H2-assisted solution route (HASR). This catalyst was designed on the basis of the following three points: (i) ultrathin NWs with high numbers of surface atoms can increase the atomic efficiency of Pt and thus decrease the catalyst cost; (ii) the incorporation of Ni can isolate Pt atoms on the surface and produce surface defects, leading to high catalytic activity (the unique structure and superior activity were confirmed by spherical aberration-corrected electron microscopy measurements and ethanol oxidation tests, respectively); and (iii) the incorporation of Mo can stabilize both Ni and Pt atoms, leading to high catalytic stability, which was confirmed by experiments and density functional theory calculations. Furthermore, the developed HASR strategy can be extended to synthesize a series of Pt-Mo-M (M = Fe, Co, Mn, Ru, etc.) NWs. These multimetallic NWs would open up new opportunities for practical fuel cell applications.

This work investigates temperature's effect on the critical energy release rate using damage mechanics material models and the element deletion method. The energy release rate describes the decrease in total potential energy per increase in crack surface area. The critical energy release rate is widely used as the failure criterion for various elastic and plastic materials. In real-life scenarios, fractures may occur at different temperatures. The temperature dependency of the critical energy release rate for aluminum 2024-T351 and titanium Ti-6Al-4V is studied in this work. We utilized test-data-based advanced material models of these two alloys, considering the strain rate, temperature, and state of stress for plasticity and failure. These material models are used to simulate a three-dimensional fracture specimen to find the critical energy release rate at different temperatures. A new method to calculate the critical energy release rate with the element deletion method is introduced and verified with the virtual crack opening method. This method enables the calculation of the energy release rate in a classical damage mechanics simulation for dynamic cack propagation. The simulation result indicates that the critical energy release rate increases with rising temperatures for these alloys. [ABSTRACT FROM AUTHOR]