15 research outputs found

    A multicentre study on the clinical characteristics of newborns infected with coronavirus disease 2019 during the omicron wave

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    ObjectiveTo investigate the clinical characteristics and outcomes of newborns infected with coronavirus disease 2019 (COVID-19) during the Omicron wave.MethodsFrom December 1, 2022, to January 4, 2023, clinical data were collected from neonates with COVID-19 who were admitted to 10 hospitals in Foshan City, China. Their epidemiological histories, clinical manifestations and outcomes were analysed. The neonates were divided into symptomatic and asymptomatic groups. The t test or χ2 test was used for comparisons between groups.ResultsA total of 286 children were diagnosed, including 166 males, 120 females, 273 full-term infants and 13 premature infants. They were 5.5 (0–30) days old on average when they were admitted to the hospital. These children had contact with patients who tested positive for COVID-19 and were infected through horizontal transmission. This study included 33 asymptomatic and 253 symptomatic patients, among whom 143 were diagnosed with upper respiratory tract infections and 110 were diagnosed with pneumonia. There were no severe or critical patients. Fever (220 patients) was the most common clinical manifestation, with a duration of 1.1 (1–6) days. The next most common clinical manifestations were cough with nasal congestion or runny nose (4 patients), cough (34 patients), poor appetite (7 patients), shortness of breath (15 patients), and poor general status (1 patient). There were no significant abnormalities in routine blood tests among the neonates infected with COVID-19 except for mononucleosis. However, compared with the asymptomatic group, in the symptomatic group, the leukocyte and neutrophil granulocyte counts were significantly decreased, and the monocyte count was significantly increased. C-reactive protein (CRP) levels were significantly increased (≥10 mg/L) in 9 patients. Myocardial enzyme, liver function, kidney function and other tests showed no obvious abnormalities.ConclusionsIn this study, neonates infected with the Omicron variant were asymptomatic or had mild disease. Symptomatic patients had lower leucocyte and neutrophil levels than asymptomatic patients

    Why Has China’s Final Consumption Rate Declined Since 1978? Causes and Implications

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    China, Consumption rate, Income distribution, Propensity of consumption, Housing reform,

    High-temperature oxidation behavior of TA15 aerospace titanium alloy at 500 °C and 800 °C

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    This study investigates the high-temperature oxidation behavior and performance of TA15 Ti alloy subjected to 500 and 800 °C service conditions. The oxidation process, microstructural evolution, mechanical property changes, and comprehensive performance were analyzed. At 500 °C, the alloy developed a distinctive blue-colored surface primarily composed of Ti6O, indicating a slow growth rate of the oxide layer. In contrast, the 800 °C condition led to severe oxidation with notable TiO2 and Al2O3 phases and extensive peeling of the oxidation layer. Microstructural analysis revealed that at 500 °C, there was minimal surface oxidation, and the microstructure showed a shallow heat-affected zone. At 800 °C, repeated oxidation and peeling cycles resulted in grain growth and a significant decrease in the β-phase proportion. Mechanical property assessments indicated an increase in micro Vickers hardness at both temperatures, with the 800 °C sample exhibiting higher values. However, tensile strength decreased significantly at 800 °C due to the severe oxidation layer peeling, reducing the effective thickness during tensile testing. In summary, TA15 demonstrated good high-temperature service performance at 500 °C, while at 800 °C, severe oxidation and peeling adversely affected the overall performance. This research provides insights into the differential high-temperature behavior of TA15, crucial for applications in elevated temperature environments

    Pseudocapacitance and diffusion-controlled dual modes of MoS2 nano-particles enable high long-cycle anode capacity

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    Molybdenum disulfide (MoS2), which generally possesses a graphene-like two-dimensional layered structure and unique physicochemical and electrical properties, is an emerging material to next-generation high-energy-density storage beyond the reach of current anode technologies. However, pristine layered MoS2 suffers from low conductivity and poor cycle stability, thus hindering its development in lithium ion batteries (LIBs). Herein, we prepare a self-assembled MoS2 nano-particle structure induced by 1-dodecanethiol (DDT) through a bottom-up approach. The superior rate and high capacity of LIBs are attributed to the large specific surface area (64.29 m2 g−1) and short internal distance, giving rise to the pseudocapacitance and diffusion-controlled process in the electrochemical behavior, respectively. In situ Raman, Density Function Theory (DFT) calculation and X-ray photoelectron spectroscopy verify the conversion from MoS2 to Mo in the lithiation process, and the strong binding energy between Mo and LiF contributes to a stable solid electrolyte interphase during Li+ intercalation/de-intercalation reversible process. The cell using MoS2 nano-particles anode delivers a preferable discharge capacity of 600 mA h g−1 after 1000 cycles at the current density of 1.0 A g−1 than commercial and recently reported MoS2 anodes. This work inspires the development of nano-structure for resistance to large-volume expansion/shrinkage and high stability

    Irradiation hardening and deuterium retention behaviour of tungsten under synergistic irradiations of 3.5 MeV Fe13+ ions and deuterium plasma

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    This work investigates the irradiation hardening and deuterium (D) retention behaviour of tungsten (W) under synergistic irradiations of heavy ions and D plasma. 3.5 MeV iron (Fe13+) ion irradiation was performed on recrystallized W samples (RW) to produce displacement damage of 1 dpa. Then, low-energy (38 eV) D plasma exposure was conducted at 500 K. It is found that Fe ion irradiation creates substantial vacancy-type defects and dislocation loops/networks in RW. These irradiation-induced defects not only function as nucleation sites for dislocations that increase the activation probability of new dislocations and suppress the pop-in events, but also act as barriers for dislocations that result in irradiation hardening. Nano-indentation results show that the average hardness of RW-D, RW-Fe and RW-Fe-D increases from 5.26 GPa for RW to 5.28, 6.23 and 6.56 GPa, respectively. The strong interaction between dislocations and high density of damage-induced defects is suggested to be the chief source for the obvious irradiation hardening observed in the synergistic irradiation case. Besides, compared with RW-D, the total D retention in RW-Fe-D is increased by a factor of 2.65. NRA and TDS results suggest that Fe pre-irradiation not only increases D retention within the damage layer (within the first 1.3 μm), but also enhances that beyond the damage layer (>1.3 μm) before surface blisters are formed. This work further improves the fundamental understanding on the microstructure evolution, D retention and nano-mechanical behaviour of W under synergistic irradiation effect of heavy ions and D plasma

    Solar-driven hydrogen generation coupled with urea electrolysis by an oxygen vacancy-rich catalyst

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    Urea, an environmental pollutant for both soil and water, is widely present in wastewater. On the other hand, a strategy utilizing renewable electricity to decrease the cost of green hydrogen, which holds the key to a sustainable energy future, is promising but challenging. Gas crossover that generates explosive hydrogen–oxygen mixture becomes very serious with intermittent renewable power source (partial load issue). Herein, we address these issues in one device, i.e., a hybrid electrolyzer where water oxidation that produces oxygen is replaced by urea oxidation which generates inert gases. A self-supported electrocatalyst of nitrogen-doped nickel-iron oxyhydroxide derived from waste rusty iron foam was synthesized via an in situ ‘waste-to-value’ synthetic route followed by an ammonia/argon plasma treatment, which reconstructed the surface of the catalyst to a 3D nanosheet-like porous network with abundant oxygen vacancies. The as-prepared catalyst showed a small potential of 1.45 V vs. RHE at 500 mA cm-2 for urea oxidation reaction. Overall water-urea electrolysis only required 1.58 V to deliver 100 mA cm-2, which was 0.33 V less than that in urea-free water splitting, and thus lowered the overall energy consumption by 17.3%. Without oxygen evolution, the hybrid electrolysis does not suffer from the safety hazard caused by explosive hydrogen–oxygen mixture. We demonstrate the safe production of green hydrogen (3.1% oxygen in the gaseous product) in the hybrid electrolysis powered by solar energy via a photovoltaic panel. Our work provides a method to address the urea-caused environmental issues and simultaneously generate green hydrogen safely using solar energy.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)Nanyang Technological UniversityAccepted versionThis work is supported by Nanyang Technological University under NAP award (M408050000), A*STAR Science & Engineering Research Council AME IRG funding (A1983c0029) and Singapore Ministry of Education Tier 1 program (2018−T1−001−051). M.Y., B.S. and W.H. acknowledge the financial support from the National Natural Science Foundation of China (Grant No. 51902041) and J.H. acknowledges the National Natural Science Foundation of China (Grant No. 21676216). M.Y. is grateful for the financial support from the program of China Scholarships Council (No. 201906070049)

    The origin, dissemination, and molecular networks of HIV-1 CRF65_cpx strain in Hainan Island, China

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    Abstract Background HIV-1 CRF65_cpx strain carries drug-resistant mutations, which raises concerns about its potential for causing virologic failure. The CRF65_cpx ranks as the fourth most prevalent on Hainan Island, China. However, the origin and molecular epidemiology of CRF65_cpx strains in this area remain unclear. This study aims to estimate the spatial origins and dissemination patterns of HIV-1 CRF65_cpx in this specific region. Methods Between 2018 and 2021, a total of 58 pol sequences of the CRF65_cpx were collected from HIV-positive patients on Hainan Island. The available CRF65_cpx pol sequences from public databases were compiled. The HIV-TRACE tool was used to construct transmission networks. The evolutionary history of the introduction and dissemination of HIV-1 CRF65_cpx on Hainan Island were analyzed using phylogenetic analysis and the Bayesian coalescent-based approach. Results Among the 58 participants, 89.66% were men who have sex with men (MSM). The median age was 25 years, and 43.10% of the individuals had a college degree or above. The results indicated that 39 (67.24%) sequences were interconnected within a single transmission network. A consistent expansion was evident from 2019 to 2021, with an incremental annual addition of four sequences into the networks. Phylodynamic analyses showed that the CRF65_cpx on Hainan Island originated from Beijing (Bayes factor, BF = 17.4), with transmission among MSM on Hainan Island in 2013.2 (95%HPD: 2012.4, 2019.5), subsequently leading to an outbreak. Haikou was the local center of the CRF65_cpx epidemic. This strain propagated from Haikou to other locations, including Sanya (BF > 1000), Danzhou (BF = 299.3), Chengmai (BF = 27.0) and Tunchang (BF = 16.3). The analyses of the viral migration patterns between age subgroups and risk subgroups revealed that the viral migration directions were from "25–40 years old" to "17–24 years old" (BF = 14.6) and to "over 40 years old" (BF = 17.6), and from MSM to heterosexuals (BF > 1000) on Hainan Island. Conclusion Our analyses elucidate the transmission dynamics of CRF65_cpx strain on Hainan Island. Haikou is identified as the potential hotspot for CRF65_cpx transmission, with middle-aged MSM identified as the key population. These findings suggest that targeted interventions in hotspots and key populations may be more effective in controlling the HIV epidemic
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