Clinical characteristics and outcomes in patients with traumatic brain injury in China: a prospective, multicentre, longitudinal, observational study

Background Large-scale studies are required to better characterise traumatic brain injury (TBI) and to identify the most effective treatment approaches for TBI. However, evidence is scarce and mostly originates from high-income countries. We aimed to describe the existing care for patients with TBI and the outcomes in China. Methods The Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) China registry is a prospective, multicentre, longitudinal, observational study done in 56 neurosurgical centres across China. We collected data of patients who were admitted to hospital with a clinical diagnosis of TBI and an indication for CT. Patients who were discharged directly from the emergency room were excluded. The primary endpoint was survival on discharge. Prognostic analyses were applied to identify predictors of mortality. Variations in mortality were compared between centres and provinces within China. Mortality was compared with expected mortality, estimated using the CRASH basic model. This study was registered with ClinicalTrials.gov, NCT02210221. Findings From Dec 22, 2014, to Aug 1, 2017, 13 627 patients with TBI from 56 centres were enrolled in the registry. Data from 13 138 patients from 52 hospitals in 22 provinces of China were analysed. Most patients were male (9782 [74%]), with a median age of 48 years (IQR 33–61). The median Glasgow Coma Scale (GCS) score was 13 (IQR 9–15), and the leading cause of injury was road-traffic incident (6548 [50%]). Overall, 637 (5%) patients died, including 552 (20%) patients with severe TBI. Age, GCS score, injury severity score, pupillary light reflex, CT findings (compressed basal cistern and midline shift ≥5 mm), presence of hypoxia, systemic hypotension, altitude higher than >500 m, and GDP per capita were significantly associated with survival in all patients with TBI. Variation in mortality existed between centres and regions. The expected 14-day mortality was 1116 (13%), but 544 (7%) deaths within 14 days were observed (observed to expected ratio 0·49 [95% CI 0·45–0·53]). Interpretation The results show differences in mortality between centres and regions across China, which indicates potential for identifying best practices through comparative effectiveness research. The risk factors identified in prognostic analyses might contribute to developing benchmarks for assessing quality of care. Funding None

Traumatic brain injury: integrated approaches to improve prevention, clinical care, and research

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Combustion Enhancement of Gel Propellant Containing High Concentration Aluminum Particles Based on Carbon Synergistic Effect

The addition of aluminum particles to gel propellants can improve combustion performance. However, the agglomeration of aluminum during the combustion process can result in a series of negative effects. In this paper, the aluminum agglomeration inhibition method of gel propellant based on carbon synergistic effect is proposed. Carbon particles exhibit excellent combustion properties, and the gaseous product CO2 generated during combustion can mitigate the agglomeration of aluminum. The research demonstrates that incorporating carbon particles into aluminum-containing gel effectively reduces the incomplete combustion of aluminum particles and increases the volumetric calorific value of the gel. When the mass fraction of carbon is 5 wt%, the volume calorific value of the gel reaches the highest. Meanwhile, the rheological experiments show that the addition of carbon particles can improve the shear-thinning properties of the gel, which is beneficial to the atomization and combustion processes of the gel

Spatiotemporal Dynamics of Dissolved Organic Carbon and Freshwater Browning in the Zoige Alpine Wetland, Northeastern Qinghai-Tibetan Plateau

The concentrations of dissolved organic carbon (DOC) and its light-absorbing fraction (chromophoric dissolved organic matter; CDOM) in surface waters, particularly those draining organic-rich peatlands, have dramatically increased over the past decade due to climate change and human disturbance. To explore the spatiotemporal dynamics of DOC and CDOM in surface waters of the northeastern Qinghai-Tibetan Plateau, we collected water samples from two rivers in the Zoige alpine wetland and from two rivers in its adjacent alpine-gorge region, during wet and dry seasons. DOC concentration ranged from 4.82 mg·L−1 to 47.83 mg·L−1, with a mean value of 15.04 mg·L−1, 2.84 times higher than the global average. The Zoige rivers had higher DOC concentration and highly terrigenous CDOM. Significantly higher DOC concentration was observed for the Zoige rivers in the wet season compared to the dry season. In contrast, the alpine-gorge rivers had higher DOC levels in the dry season. No significant correlations were observed between DOC and CDOM at all rivers due to the influence of autochthonous sources on the alpine-gorge rivers and intensive photochemical degradation of terrigenous DOM in the Zoige rivers. Significant relationships between CDOM and specific ultraviolet absorbance at 254 nm (SUVA254) and between CDOM/DOC and SUVA254 were observed, indicating that the aromaticity of DOM in the rivers was mainly determined by CDOM. Moreover, the DOC/CDOM properties of the Hei River indicate critical human-induced water quality degradation. High DOC level and high browning degree were found in rivers in the Zoige alpine wetland, indicating that large amounts of terrigenous DOC were released to the aquatic systems of the region

Variations in Soil Enzyme Activities and Microbial Communities along an Altitudinal Gradient on the Eastern Qinghai–Tibetan Plateau

The Qinghai–Tibetan Plateau is the highest plateau in the world and is sensitive to climate change. The dynamics of soil enzyme activities and microbial communities are good indicators of alpine biochemical processes during warming. We collected topsoil (0–10 cm) and subsoil (10–20 cm) samples at altitudes of 3200–4000 m; determined the activities of β-1,4-glucosidase (BG), cellobiohydrolase (CBH), β-1,4-N-acetyl-glucosaminidase (NAG) and acid phosphomonoesterase (PME); and performed Illumina 16S rRNA high-throughput sequencing. We found that the soil carbon (total organic carbon and dissolved organic carbon) and nitrogen (total nitrogen and dissolved organic nitrogen) fluctuated with altitude in both the topsoil and subsoil, whereas the dissolved phosphorus continuously decreased with the increasing altitude. BG and CBH decreased from 3200 to 3600 m and increased from 3800 to 4000 m, with the lowest levels occurring at 3600 m (topsoil) and 3800 m (subsoil). NAG and PME showed similar fluctuations with altitude, with the highest levels occurring at 3400 m and 4000 m in both the topsoil and subsoil. Generally, the altitudes from 3600 to 3800 m were an ecological transition belt where most of the nutrients and enzyme activities reached their lowest levels. All of the alpine soils shared similar dominant phyla, including Proteobacteria (32.7%), Acidobacteria (30.2%), Actinobacteria (7.7%), Bacteroidetes (4.4%), Planctomycetes (2.9%), Firmicutes (2.3%), Gemmatimonadetes (2.0%), Chloroflexi, (1.2%) and Nitrospirae (1.2%); Gemmatimonadetes and Verrucomicrobia were significantly affected by soil depth and Planctomycetes, Firmicutes, Gemmatimonadetes, Nitrospirae, Latescibacteria and Armatimonadetes were significantly affected by altitude. In addition, nutrient availability, enzyme activity and microbial diversity were higher in the topsoil than in the subsoil, and they had more significant correlations in the subsoil than in the topsoil. Our results provide useful insights into the close linkages between soil nutrient cycling and microbial activities on the eastern Qinghai–Tibetan Plateau, and are of great significance for further assessing the long-term impact of environmental changes in the alpine ecosystems

Study on the Dynamic Problems of Double-Disk Rotor System Supported by Deep Groove Ball Bearing

Aiming at the analysis of the dynamic characteristics of the rotor system supported by deep groove ball bearings, the dynamic model of the double-disk rotor system supported by deep groove ball bearings was established. In this paper, the nonlinear finite element method is used combined with the structural characteristics of deep groove ball bearings. Based on the nonlinear Hertz contact theory, the mechanical model of deep groove ball bearings is obtained. The excitation response results of the rotor system nodes are solved by using the Newmark-β numerical solution method combined with the Newton–Raphson iterative method. The vibration characteristics of the rotor system supported by deep groove ball bearings are studied deeply. In addition, the effect of varying compliance vibration (VC vibration) caused by the change in bearing support stiffness on the dynamics of the system is considered. The time domain and frequency domain characteristics of the rotor system at different speeds, as well as the influence of bearing clearance and bearing inner ring’s acceleration on the dynamics of the rotor system are analyzed. The research shows that the VC vibration of the bearing has a great influence on the motion of the rotor system when the rotational speed is low. Moreover, reasonable control of bearing clearance can reduce the mutual impact between the bearing rolling element and the inner or outer rings of the bearing and reduce the influence of unstable bearing motion on the vibration characteristics of the rotor system. The results can provide theoretical basis for the subsequent study of the nonlinear vibration characteristics of the deep groove ball bearing rotor system