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Vaccination is the primary defense against severe acute respiratory syndrome coronavirus 2, especially among older adults and those with chronic conditions. Using a nationally representative sample of 12,900 participants from the fifth wave (2021–2022) of the China Health and Retirement Longitudinal Study (CHARLS), we examined the coronavirus disease 2019 (COVID-19) vaccination status and the determinants of vaccination hesitancy in Chinese adults aged 52 and older. By July/August 2022, 92.3% of the Chinese population aged 60 years and older had received at least one COVID-19 vaccination, 88.6% had completed the primary series and 72.4% had received a booster. Those aged 80 years and older had lower vaccination rates, with 71.9% and 46.7% completing the primary series and booster shots, respectively. These statistics represent the situation before China ended the Zero-COVID policy in November 2022 because vaccination stagnated between July/August and November 2022. Multivariate regression analysis revealed that belonging to the oldest age groups (individuals aged 70 years and older and especially those aged 80 years and older) as well as being female and unmarried, residing in urban areas, being functionally dependent and having chronic conditions meant that these individuals were less likely to receive COVID-19 vaccines. Our regression analysis results were corroborated by self-reported reasons for nonvaccination. Vaccination hesitancy probably contributed to excessive mortality among vulnerable populations after China ceased its Zero-COVID policy. Our study provides important lessons on how to balance containment efforts with vaccination and treatment measures, as well as highlighting the need to clarify the side effects and contraindications of vaccines early on.

China has a lower rate of vaccination among older adults and those who have chronic conditions and functional disabilities. As China has recently ended the zero-COVID policy, understanding the factors behind low vaccination rates among these vulnerable populations can inform immediate policy priorities to save lives for China and offer lessons for the world at large. We used the fifth wave (2021-22) of the China Health and Retirement Longitudinal Study (CHARLS), which represented mainland Chinese 45 and older. Vaccination status was updated in the summer of 2022, reflecting the current situation because very few additional vaccinations were administered afterward. For those who were unvaccinated, self-reported reasons were recorded. Using regression analysis, we investigated the determinants of non-vaccination, including demographics, functional status, and chronic conditions. In addition, two-thirds of the respondents had their vaccination status recorded twice in 2021 and 2022, allowing us to examine changes in vaccination rates in the recent year, zeroing in on the effects of the government's most recent vaccination campaign. Finally, we corroborated the regression results using self-reported reasons for non-vaccination in both years. A total of 12900 participants were included in the analysis. By the summer of 2022, the weighted COVID-19 vaccination rate among older Chinese people (≥60 years old) was 92.3%, with 88.8% having completed the primary series and 72.7% having received boosters. Only 72.0% of the oldest-old (≥80 years old) had completed the primary series, and 47.1% had had boosters. Regression analysis showed that participants who were older, female, unmarried, registered with urban Hukou residence, functionally dependent, and comorbid with chronic conditions were less likely to receive COVID-19 vaccines. A significant increase in vaccination rates among ethnic minorities, older adults, rural residents, and those with chronic conditions and functional dependency was observed in the year after the winter of 2021 when the government started to push for universal vaccination. The self-reported reasons for non-vaccination in 2022 were contraindications (48%), advanced ages/frailty/health conditions (21%), problems in accessing vaccines (18%), concerns about side effects or efficacy (9%), and having never heard of COVID-19 vaccine (6%). Nevertheless, as China has ended the zero-COVID policy, many older people, especially the oldest and those with chronic conditions and disabilities, have not yet been fully vaccinated with the primary series or booster doses, exposing them to the danger of infection. Therefore, health authorities should immediately abandon the previous practice of refusing to vaccinate those with chronic conditions, change people's mistaken perceptions of contraindications and side effects, and improve access to vaccines. Most importantly, China should strengthen public trust in vaccines by making information transparent regarding the vaccine's protection rates and side effects.

Mechanical structures are often simultaneously subjected to thermal and mechanical loading, both of which can lead to buckling failure. Developing efficient structural forms with better capacity for stability is important to keep structures safe. This study aims to optimize structural buckling capacity by using a density-based topology optimization scheme. Instead of treating the mechanical and thermal loadings as a single coupled part in the linearized buckling analysis, the effects of mechanical and thermal loadings are decoupled, which allows to separately analyze and optimize buckling aspects induced by mechanical or thermal loading. Two optimization models based on the decoupled analysis models are developed to respectively maximize the critical load factor of buckling induced by mechanical loading under a specified thermal loading and buckling induced by thermal loading under a specified mechanical loading. Further, based on a three-phase material model, a multi-material topology optimization scheme is employed to optimize the buckling capacity of active structures made of structural and actuating materials and prestressed structures containing prestressed components. The actuation effects are mimicked by the thermal loading of active material. The sensitivities of the objective functions and constraints are derived through the adjoint technique, and the method of moving asymptotes (MMA) is employed to solve the topology optimization problems. Numerical examples are adopted to verify the effectiveness of the proposed approach.

The construction industry takes up a significant part of global energy consumption and carbon emissions, and thus accurate calculation and evaluation of full life-cycle energy consumption and carbon emissions of different types of building structures are important for low carbon-oriented structural design. Large-span structures usually consume more materials, need more complex construction processes, and thus have a larger environmental impact. In this study, the life cycle assessment of the carbon emission of space frame structures which is a classical type of large-span structure is conducted. Space frame structures with bolted spherical joints and space frame structures with welded hollow spherical joints are considered. The life cycle of a space frame structure is divided into four phases including component production, construction, maintenance, and demolition. The tiered hybrid method that combines process-based calculation and input-output analysis is adopted to evaluate the carbon emission of space frame structures. Parametrical studies on the height-span ratio and grid number are carried out using the proposed assessment scheme. The carbon emissions of the space frame structures with different types of joints are investigated and compared. It is found that lower material consumption does not always result in lower carbon emission, and thus it is necessary to evaluate the life-cycle carbon emission during lower carbon-oriented design of space frame structures. An equation for approximately and quickly estimating the carbon emission of space frame structures is fitted from the material consumption to carbon emission datum obtained from the parametrical studies. This study provides a useful reference for the carbon emission assessment and low-carbon oriented design of space frame structures.

Nanodiamonds (NDs) were prepared under ambient pressure by sublimation decomposition of silicon carbide in an intermediate frequency furnace for only 8 min. The synthesis proceeded in the temperature range of 2600-2800°C without any catalyst or highly active gas components (such as H2, alkane, and halogen). The conversion began at 2600°C and produced NDs with particle sizes in the range of 1-5 nm with a uniform particle shape and excellent dispersion. The linear reaction kinetics allowed for rapid transformation to any depth with reasonable control of the temperature. The linear rate constant (Kl) for the reaction at 2800°C was 37.5 mm/h, which is 31.2 times that of the reaction at 2600°C. The SiC sublimation decomposition produced carbon atoms that filled the SiC lattice vacancies or were combined with the suspended carbon chain bonds to form sp3 carbon, while the diffusion of amorphous carbon atoms promoted nucleation and growth of diamond. High-resolution transmission electron microscopy analysis indicated that the NDs were separated from the SiC matrix by break-off due to propagation of the reaction front. This SiC sublimation decomposition method is considered simple, fast, environmentally friendly and promising for industrial-scale production.

At Quesang on the Tibetan Plateau we report a series of hand and foot impressions that appear to have been intentionally placed on the surface of a unit of soft travertine. The travertine was deposited by water from a hot spring which is now inactive and as the travertine lithified it preserved the traces. On the basis of the sizes of the hand and foot traces, we suggest that two track-makers were involved and were likely children. We interpret this event as a deliberate artistic act that created a work of parietal art. The travertine unit on which the traces were imprinted dates to between ∼169 and 226 ka BP. This would make the site the earliest currently known example of parietal art in the world and would also provide the earliest evidence discovered to date for hominins on the High Tibetan Plateau (above 4000 m a.s.l.). This remarkable discovery adds to the body of research that identifies children as some of the earliest artists within the genus Homo.

As the approach of fifth-generation (5G) era, the auto industry has received good development opportunities, which is one of the industry that has benefited most from 5G. Based on the powerful communication of 5G NR, all the information of vehicle running performance can be uploaded to the cloud. With the help of cloud computing, multiple internet of vehicles (IoV) applications come into existence. In this paper, the performance verification methods for typical IoV applications will be introduced in more details. Under each application scenario, we first determine a suitable traffic model, and further analyze how some key performance indicators (KPI) vary as the number of vehicles increases.

With more distributed power generation and renewable energy penetration, voltage fluctuation and power generation variation can be observed more frequently in the modern power distribution network. More tap change operations are required for the step voltage regulator (SVR) to regulate the line voltage. However, the tap changing mechanism of the conventional SVR always generates an electric arc when tap changes, which imposes constraints on conventional SVRs, such as lifetime and maintenance period. This article proposed a new topology of arcless step voltage regulator based on a series-connected converter for current suppression. The system efficiency is the same as the conventional SVR in the normal operation, while the converter power rating is only 0.3% of the total system power. A scaled-down prototype of the arcless SVR is developed to verify the proposed arcless tap changing method. The hardware test results verified that the proposed arcless step voltage regulator can eliminate arcing during the tap change and reduce the contact erosion rate by over 10000 times the conventional arcing SVR. Other advantages of the novel method over the conventional SVR, such as advanced load voltage regulation and volt/var control, are also verified.

A 3D digital model of a small Unmanned Aerial Vehicle (UAV) is obtained by using the method of scanning reverse modeling and joint mapping. A numerical simulation of a small UAV strikes on rotary engine blades, presented in this paper, was performed with a Transient Nonlinear Finite Element code PAM-CRASH software. A test of motor strike on plate was developed and the dynamic response of the plate were obtained to validate the numerical simulation method of a UAV strike on blades. Based on this, dynamic damage response caused by UAV on the engine blades were studied. It is indicated that the impact process between the UAV and a single blade can be divided into two typical stages: cutting and impact. Cutting mainly leads to the failure of the leading edge material, and impact mainly leads to the plastic deformation of the blade. At the same time, it is compared with the damage impacted by bird with the same mass. For the same mass of bird and UAV, the damage caused by UAV striking fan blade is more serious, and 1.345 kg UAV striking fan blade of typical civil aviation engine is enough to cause damage to flight safety.

Radial growth of high-elevation shrubs shows the high sensitivity to climate in dry regions, providing new evidence for drought-mediated dynamics of alpine woody plants. In mountains, shrubs forming their uppermost distributional limits (shrubline) are highly sensitive to increasing cold limitations upwards. However, the constraints imposed by a shorter growing season due to lower temperatures upslope could interact with drought stress in mountainous regions. Here, we aim to investigate that question by comparing radial growth patterns of shrubs in wet (forest region of Nangqian County, BZ hereafter) vs. dry (forest region of Leiwuqi County, LWQ hereafter) regions located on the eastern Tibetan plateau. Considering the climate trend in this area towards warmer and drier conditions, we hypothesize that growth of high-elevation shrubs will be mainly limited by low summer temperatures under sufficient soil moisture. To test this hypothesis, we collected ring-width data from 123 alpine shrubs (Salix oritrepha Schneid.) along an altitudinal gradient from 4200 to 4600 m a.s.l. Dendroecological analyses showed that shrub growth was positively related to mean June or July temperature during the past decades in both wet (BZ) and dry (LWQ) regions regardless of site elevation. By contrast, correlations between shrub growth and seasonal precipitation were not significant. Shrub growth trends were positive before 2010 but turned negative afterwards. Overall, radial growth of shrubs along the altitudinal gradients up to the shrubline could shift from being temperature to moisture limited if warming-induced drought stress intensifies.

The lung is one of the most commonly encountered sites of Scedosporium infection. Due to its intrinsic resistance to all current antifungal agents, treatment of Scedosporium infections still remains a great challenge. Voriconazole has been recommended to the first-line systemic treatment of Scedosporium infections, but the duration is not well recommended, especially for immunocompetent patients. This case series presented our experience on diagnostic, manifestation, and treatment strategies of Scedosporium pneumonia. The case records of non-Transplanted non-HIV adults with Scedosporium pneumonia hospitalized in our Hospital from January 2020 to February 2022 were retrospectively analyzed, and their case characteristics, antifungal therapy drug selection and treatment course were summarized: All 3 patients had underlying lung disease, 2 female patients had a history of bronchiectasis, and 1 male patient had a history of emphysema. Both female patients had a mixed infection with Scedosporium and nontuberculous mycobacteria. In one female patients, Scedosporium was no longer detected after 2 months of treatment with voriconazole, and the clinical symptoms were improved than before, with no significant change in imaging. In one female patient, although Scedosporium was still isolated from sputum after 12 months with voriconazole treatment, the symptoms were improved than before, and antifungal therapy was discontinued after no significant improvement 1 and a half months after switching to Posaconazole. In one male patient, Scedosporium was no longer detected after 3 months treatment with voriconazole, and the clinical symptoms and imaging were significantly improved. Three patients had voriconazole concentrations between 1.1-2.8 μg/mL during treatment.