Fast charging of energy-dense lithium-ion batteries.

Lithium-ion batteries with nickel-rich layered oxide cathodes and graphite anodes have reached specific energies of 250-300 Wh kg-1 (refs. 1,2), and it is now possible to build a 90 kWh electric vehicle (EV) pack with a 300-mile cruise range. Unfortunately, using such massive batteries to alleviate range anxiety is ineffective for mainstream EV adoption owing to the limited raw resource supply and prohibitively high cost. Ten-minute fast charging enables downsizing of EV batteries for both affordability and sustainability, without causing range anxiety. However, fast charging of energy-dense batteries (more than 250 Wh kg-1 or higher than 4 mAh cm-2) remains a great challenge3,4. Here we combine a material-agnostic approach based on asymmetric temperature modulation with a thermally stable dual-salt electrolyte to achieve charging of a 265 Wh kg-1 battery to 75% (or 70%) state of charge in 12 (or 11) minutes for more than 900 (or 2,000) cycles. This is equivalent to a half million mile range in which every charge is a fast charge. Further, we build a digital twin of such a battery pack to assess its cooling and safety and demonstrate that thermally modulated 4C charging only requires air convection. This offers a compact and intrinsically safe route to cell-to-pack development. The rapid thermal modulation method to yield highly active electrochemical interfaces only during fast charging has important potential to realize both stability and fast charging of next-generation materials, including anodes like silicon and lithium metal.

Intrinsic relationship of outdoor activities between climate change and coastal management: Fresh evidence from the spatial analysis of China.

By utilizing the mediation effect model and the spatial Durbin model, this research investigates the influence that environmental restrictions have had on marine pollution in 38 coastal prefecture-level cities from the years 2000-2018. In order to gain a comprehensive understanding of the effect that environmental legislation has on contamination in offshore regions as well as its primary goal, the research takes a variety of different approaches into consideration. Following are the findings from the study; Firstly, pollution levels in coastal marine areas tend to rise at first and then fall when environmental laws are enacted, illustrating a non-linear pattern known as an inverted "U" shape. In order to improve the maritime environment through environmental legislation, it is crucial to support new green technologies. There is a "U" shaped linkage amongst environmental legislation and development of environmentally friendly technologies. Spatial spillover effects may allow for the regulation of coastal city environments to affect marine pollution in neighboring areas. Secondly, there is also an inverted "U" pattern visible in the impact trajectory of this effect. According to the results of this research, it is crucial to set up a strict and factually sound regulatory framework in the field of marine environmental governance. It is also suggested that local context be taken into account while crafting environmental regulating regulations. Also, it's crucial to promote development, dissemination, and use of green technology by completely capitalizing on the innovation's conduction effect. Thirdly, promoting cooperation efforts among areas to avoid and control such pollution is essential, and the transfer and management of offshore pollution between regions must be a top priority.

[Blood cadmium level and the change of cadmium exposure risk in Chinese urban school-age children in 2002 and 2012].

OBJECTIVE: To investigate the blood cadmium concentrations and the related change in Chinese urban children derived from the China Nutrition and Health Survey 2002 and 2012(CNHS 2002 and CNHS 2012). METHODS: The Chinese urban children aged 6-11 years were selected according to gender, age and regional distribution using the multi-stage stratified cluster random sampling method, as well as the corresponding whole blood samples. The blood cadmium concentration was carefully determined by the quadrupole inductively coupled plasma mass spectrometry(ICP-MS) and the percentage of blood cadmium over 2 µg/L was subsequently estimated. In addition, the upper limit values of the 95%CI of the 95th percentiles of available blood cadmium data was assessed as the threshold of cadmium exposure. RESULTS: Totally, 2182 Chinese urban children were included, and of these, 1036 children were from the CNHS 2002 and 1146 children were from the CNHS 2012. From the CNHS 2002 to the CNHS 2012, the median blood cadmium concentration was increased from 0.28 µg/L to 0.95 µg/L, and the percentage of blood cadmium with over 2 µg/L was elevated from 1.45% to 10.47%. In addition, the new estimated threshold of blood cadmium was ascended from 1.24 µg/L up to 2.89 µg/L. CONCLUSION: The risk of cadmium exposure in Chinese urban children aged 6-11 years was increasingly aggravated from the CHNS 2002 to the CNHS 2012.

Ultra-high thermal stability InAs/GaAs quantum dot lasers grown on on-axis Si (001) with a record-high continuous-wave operating temperature of 150 °C.

Direct epitaxial growth of group III-V light sources with excellently thermal performance on silicon photonics chips promises low-cost, low-power-consumption, high-performance photonic integrated circuits. Here, we report on the achievement of ultra-high thermal stability 1.3 µm InAs/GaAs quantum dot (QD) lasers directly grown on an on-axis Si (001) with a record-high continuous-wave (CW) operating temperature of 150 °C. A GaAs buffer layer with a low threading dislocation density (TDD) of 4.3 × 106 cm-2 was first deposited using an optimized three-step growth method by molecular beam epitaxy. Then, an eight-layer QD laser structure with p-type modulation doping to enhance the temperature stability of the device was subsequently grown on the low TDD Si-based GaAs buffer layer. It is shown that the QD laser exhibits the ultra-high temperature stability with a characteristic temperature T0=∞ and T1=∞ in the wide temperature range of 10-75 °C and 10-140 °C, respectively. Moreover, a maximum CW operating temperature of up to 150 °C and a pulsed operating temperature of up to 160 °C are achieved for the QD laser. In addition, the QD laser shows a high CW saturation power of 50 mW at 85 °C and 19 mW at 125 °C, respectively.

Significantly enhanced performance of InAs/GaAs quantum dot lasers on Si(001) via spatially separated co-doping.

We report the significantly enhanced performance of InAs/GaAs quantum dot (QD) lasers on Si(001) by spatially separated co-doping, including n-doping in the QDs and p-doping in the barrier layers simultaneously. The QD lasers are a ridge waveguide of 6 × 1000 µm2 containing five InAs QD layers. Compared with p-doped alone laser, the co-doped laser exhibits a large reduction in threshold current of 30.3% and an increase in maximum output power of 25.5% at room temperature. In the range of 15°C-115°C (under 1% pulse mode), the co-doped laser shows better temperature stability with higher characteristic temperatures of threshold current (T0) and slope efficiency (T1). Furthermore, the co-doped laser can maintain stable continuous-wave ground-state lasing up to a high temperature of 115°C. These results prove the great potential of co-doping technique for enhancing silicon-based QD laser performances towards lower power consumption, higher temperature stability, and higher operating temperature, to boost the development of high-performance silicon photonic chips.

Sodium content targets for pre-packaged foods, China: a quantitative study and proposal.

Objective: To determine the contribution of pre-packaged foods to population sodium intake in China, and to propose sodium content targets for food subcategories used for the World Health Organization's (WHO's) global sodium benchmarks. Methods: The impact of four different approaches to reducing the sodium content of pre-packaged foods on population sodium intake was estimated using data from national databases covering the nutrient content and ingredients of 51 803 food products and food consumption by 15 670 Chinese adults. We recategorized food products using a food categorization framework developed for WHO's global sodium benchmarks and adapted for China-specific foods. Findings: Pre-packaged foods, including condiments, contributed 1302.5 mg/day of sodium intake per adult in 2021, accounting for 30.1% of population sodium intake in China. Setting maximum sodium content levels using a 90th-percentile target would reduce sodium intake from pre-packaged foods by 96.2 mg/day, corresponding to a 1.9% reduction in population intake. Using the 75th-percentile, a fixed 20% reduction and WHO benchmark targets would further reduce intake by 262.0 mg/day (5.2% population intake), 302.8 mg/day (6.0% population intake) and 701.2 mg/day per person (13.9% population intake), respectively. Maximum sodium content levels based on revised 20% reduction targets were proposed because they should result in substantial and acceptable reductions in sodium content for most food subcategories: overall sodium intake would decline by 305.0 mg/day per person, and population intake by 6.1%. Conclusion: This study provides the scientific rationale for government policy on setting targets for food sodium content in China. Simultaneous action on discretionary salt use should also be taken.

Re-exploration of dietary iodine intake in Chinese adult males using a modified iodine balance study.

There is still controversy about optimal dietary iodine intake as the Universal Salt Iodization policy enforcement in China. A modified iodine balance study was thus conducted to explore the suitable iodine intake in Chinese adult males using the iodine overflow hypothesis. In this study, thirty-eight apparently healthy males (19·1 (sd 0·6) years) were recruited and provided with designed diets. After the 14-d iodine depletion, daily iodine intake gradually increased in the 30-d iodine supplementation, consisting of six stages and each of 5 d. All foods and excreta (urine, faeces) were collected to examine daily iodine intake, iodine excretion and the changes of iodine increment in relation to those values at stage 1. The dose-response associations of iodine intake increment with excretion increment were fitted by the mixed effects models, as well as with retention increment. Daily iodine intake and excretion were 16·3 and 54·3 µg/d at stage 1, and iodine intake increment increased from 11·2 µg/d at stage 2 to 118·0 µg/d at stage 6, while excretion increment elevated from 21·5 to 95·0 µg/d. A zero iodine balance was dynamically achieved as 48·0 µg/d of iodine intake. The estimated average requirement and recommended nutrient intake were severally 48·0 and 67·2 µg/d, which could be corresponded to a daily iodine intake of 0·74 and 1·04 µg/kg per d. The results of our study indicate that roughly half of current iodine intakes recommendation could be enough in Chinese adult males, which would be beneficial for the revision of dietary reference intakes.

Re-exploring the requirement of dietary iodine intake in Chinese female adults based on 'iodine overflow theory'.

PURPOSE: We re-explored the basal iodine requirement based on healthy Chinese female and a new iodine overflow theory was proposed for iodine balance study. METHODS: Thirty-six Chinese healthy female adults (age 20.7 ± 1.1) were recruited for this study, which included 40 days low iodine depletion period and six stages of 30 days supplementation period. Uniform diets with low iodine were provided and the content of iodine in the diet was regulated by dairy products. The total iodine intake from food and the total iodine excretion through 24-h urine and staged feces were completely gathered and monitored. The incremental (Δ) intake and excretion over the range were calculated. RESULTS: The iodine intake and excretion were 13.6 µg/day and 48.6 µg/day at the first stage, respectively. The incremental iodine intakes and excretions were 21.1 µg/day to 120.3 µg/day and 25.8 µg/day to 105.4 µg/day for the supplementation stages, respectively. According to the 'iodine overflow theory', the zero iodine balance (Δ iodine intake = Δ iodine excretion) derived from a mixed effect model indicated a mean iodine intake of 52.2 µg/d (1.0 µg/d kg). The RNI for iodine to healthy Chinese female adult was 73.1 µg/d (1.4 µg/d kg). CONCLUSION: A daily iodine intake of 52.2 µg/d may meet the basal iodine requirement for healthy Chinese female adults, and Chinese female may need more than 20% iodine intake than male based on the 'iodine overflow theory'. The trial was registered at the Chinese Clinical Trial Registry in May 2018 (No: ChiCTR1800016184).

Scanning the latent phases and superconductivity in the Nb-Pb system at high pressure.

So far, few literature studies have been reported on niobium-lead binary intermetallic compounds, which are expected to have very different properties compared to existing niobium-carbon binary compounds, due to the distinct electronic properties of lead when compared to other carbon-group elements. Herein, we carry out a global structure search for the Nb-Pb system based on the evolutionary algorithm and density functional theory. Based on the dynamical and mechanical stability analyses, we unveiled five new phases, P4/m-Nb9Pb, Cmcm-Nb3Pb, I4/mmm-Nb2Pb, Pmm2-Nb5Pb3, and I4/mmm-NbPb2, that are promising candidates for experimental synthesis. Moreover, the superconducting transitions of all Nb-Pb binary intermetallic compounds are performed with electron-phonon calculations. As Nb9Pb exhibited the maximum Tc in the Nb-Pb intermetallics, greater than 3.0 K at 20 GPa, the phonon band structures, partial phonon density of states (PHDOS), the corresponding Eliashberg spectral functions α2F(ω), and integral electron-phonon coupling (EPC) parameters λ as a function of frequency of Nb9Pb were also studied. This work filled the gap in the pressure-tuned Nb-Pb phase transitions from a systematic first principles study for the first time.

Correlation of endocrine disrupting chemicals with essential elements in biological samples of children (1-5 years) with different infectious diseases and impact on sustainable outdoor activities.

Endocrine disrupting chemicals (EDCs) have been extensively explored due to their harmful effects on individual health and the environment by interfering with hormone activity and disrupting the endocrine system. However, their relationship with essential trace elements remains uncertain. This research aimed to investigate the possible correlation between essential trace elements and toxic metals, including cadmium (Cd), and lead (Pb) in children aged 1-5 years with various infectious diseases, including gastrointestinal disorders, typhoid fever, and pneumonia. The study was conducted on biological testing and specimen (scalp hair and whole blood) of diseased and non-diseased children of the same residential area and referent/control age-matched children from developed cities consuming domestically treated water. The media of biological samples were oxidized by an acid mixture before being analyzed by atomic absorption spectrophotometry. The accuracy and validity of the methodology were verified through accredited reference material from scalp hair and whole blood sample. The study results revealed that diseased children had lower mean values of essential trace elements (iron, copper, and zinc) in both scalp hair and blood, except for copper, which was found to be higher in blood samples of diseased children. This implies that the deficiency of essential residue and trace elements in children from rural areas who consume groundwater is linked to various infectious diseases. The study highlights the need for more human biomonitoring of EDCs to better comprehend their non-classical toxic properties and their concealed costs on human health. The findings suggest that exposure to EDCs could be associated with unfavorable health outcomes and emphasizes the need for future regulatory policies to minimize exposure and safeguard the health of current and forthcoming generations of children. Furthermore, the study highlights the implication of essential trace elements in maintaining good health and their potential correlation with toxic metals in the environment.

Rice yield benefits from historical climate warming to be negated by extreme heat in Northeast China.

Rice is currently benefiting from climate warming in Northeast China, but whether such positive effect will continue in the future remains unknown. Here, we evaluate the impacts of individual and combined climate variables on rice yields in Northeast China during 1980-2015. Results show that there is 10% yield increase induced by climate change in Northeast China since 1980. At present, the reduced chilling results in 5.4% yield increase (approximately 28,000 tons) and the higher growing degree-day contributes to 4.6% yield increase (approximately 24,000 tons), while the high-temperature extreme reduced yield by 0.054% (approximately 280 tons). However, with continuous warming, the harmful impact of such high-temperature extreme will outweigh other positive climate effects when the temperature increases by 3.36 °C. Therefore, high-temperature extremes cannot be ignored despite their influence on rice yield being quite limited at present in Northeast China. Climate change mitigation and heat tolerance breeding are thus necessary for rice production in Northeast China.

Spatial-temporal patterns of high-temperature and drought during the maize growing season under current and future climate changes in northeast China.

BACKGROUND: Under the background of global warming, the intensity and frequency of extreme meteorological events in the maize growing season in northeast China are increasing. In order to clarify the occurrence characteristics of extreme meteorological events in northeast China, this study focused on three extreme agrometeorological events, i.e., high temperatures, drought, and the compound events of high-temperature and drought during the maize growing season (May-September), impacting maize production. RESULTS: Based on historical (1981-2017) and future (2021-2060) climate data, we analyzed the spatial-temporal patterns of these three events with different intensities in northeast China. The results indicated that slight high-temperatures and moderate and severe droughts occurred more frequently in the study area during the historical period. The frequency of the different grades of the compound events of high-temperature and drought will exhibit an increasing trend in the future, as will the frequency of the compound events of high-temperature and drought. This is particularly evident in the northwest of the study area. CONCLUSION: The compound events of high-temperature and drought mainly occurred in late July and early August, encompassing the flowering stage of maize varieties. It is important to identify the area and time of major extreme weather events to implement the necessary preventive measures. © 2023 Society of Chemical Industry.

The heat stress during anthesis and the grain-filling period of spring maize in Northeast China is projected to increase toward the mid-21st century.

BACKGROUND: Against the background of global warming, heat stress has become more frequent, which adversely affects the growth and development of spring maize plants in Northeast China. To adapt the regional maize production to climate change, it is imperative to understand the spatio-temporal characteristics of heat stress. In the present study, we analyzed three of the indices for heat stress, including the number of heat stress days, heating degree days (HDD, the total heat degree-days during critical stages), and the percentage of stations with heat stress. RESULTS: From 1981 to 2019, the number of heat stress days varied greatly among the study years, ranging from 0 to 14 and 27 days, respectively. The average HDD was 7.8 and 5.0 °C day from 1981 to 2000, respectively, and the main hot-spots of heat stress occurred in the southwest regions. Moreover, compared with 1981-2000, the region of HDD during anthesis higher than 10 °C day in 2041-2060 under the SSP1-2.6 and SSP5-8.5 climate scenarios increased by 9.1-50.1% and 0.1-28.6%. The average HDD during the critical stages from 2041 to 2060 increased under the SSP5-8.5 climate scenario, being 1.5 times higher than that during 1981-2000. HDD during maize anthesis and the grain-filling period showed an overall increasing trend with years. About 19% and 58% of the study locations showed heat stress during the past 39 years, respectively. CONCLUSION: Heat stress during anthesis and the grain-filling period for spring maize in Northeast China is projected to increase toward the mid-21st century. © 2023 Society of Chemical Industry.

Late-Stage Dehydroxyazidation of Alcohols Promoted by Trifunctional Hypervalent Azido-Iodine(III) Reagents.

The development of convenient new methods for the synthesis of organic azides is highly desirable. Herein, we report a practical method for dehydroxyazidation of alcohols via an SN 2 pathway involving PPh3 and trifunctional benziodazolone-based hypervalent azido-iodine(III) reagents, which function as an electrophilic center, an azido source, and a base. This mild, chemoselective method was used for late-stage azidation of structurally complex alcohols, as well as for a new synthetic route to the antiepileptic drug rufinamide. The reaction mechanism was also investigated both experimentally and computationally.

Lithium-ion battery structure that self-heats at low temperatures.

Lithium-ion batteries suffer severe power loss at temperatures below zero degrees Celsius, limiting their use in applications such as electric cars in cold climates and high-altitude drones. The practical consequences of such power loss are the need for larger, more expensive battery packs to perform engine cold cranking, slow charging in cold weather, restricted regenerative braking, and reduction of vehicle cruise range by as much as 40 per cent. Previous attempts to improve the low-temperature performance of lithium-ion batteries have focused on developing additives to improve the low-temperature behaviour of electrolytes, and on externally heating and insulating the cells. Here we report a lithium-ion battery structure, the 'all-climate battery' cell, that heats itself up from below zero degrees Celsius without requiring external heating devices or electrolyte additives. The self-heating mechanism creates an electrochemical interface that is favourable for high discharge/charge power. We show that the internal warm-up of such a cell to zero degrees Celsius occurs within 20 seconds at minus 20 degrees Celsius and within 30 seconds at minus 30 degrees Celsius, consuming only 3.8 per cent and 5.5 per cent of cell capacity, respectively. The self-heated all-climate battery cell yields a discharge/regeneration power of 1,061/1,425 watts per kilogram at a 50 per cent state of charge and at minus 30 degrees Celsius, delivering 6.4-12.3 times the power of state-of-the-art lithium-ion cells. We expect the all-climate battery to enable engine stop-start technology capable of saving 5-10 per cent of the fuel for 80 million new vehicles manufactured every year. Given that only a small fraction of the battery energy is used for self-heating, we envisage that the all-climate battery cell may also prove useful for plug-in electric vehicles, robotics and space exploration applications.

Exploration of the lower threshold of iodine intake in Southern Chinese young adults based on 'overflow theory' in an iodine balance study.

BACKGROUND: Appropriate iodine intake for adults is essential to reduce the prevalence of thyroid diseases, but there is little research data on iodine requirement of Chinese population. This study aimed to explore the iodine requirement of young adults to maintain a healthy status based on 'overflow theory'. METHODS: Iodine-balance experiment has been performed in this project. We conducted an 18-day study consisted of a 6-day acclimation period and 3 consecutive experimental stages in 37 Chinese healthy young adults (23 female and 14 male). Each stage was consumed for 4 days. Strictly-controlled low-iodine intake diets were provided for adults in the first period, an egg or 125mL milk was added in the second and third period, respectively. The dietary samples, 24-h urine specimens and faeces of volunteers were collected daily for assessment of iodine intake and excretion in volunteers. RESULTS: Mean values of iodine intake (22.7±3.6, 35.1±3.7, and 52.2±3.8µg/d), excretion (64.7±13.9, 62.3±12.6, and 94.3±14.5µg/d) and iodine balance (-35.2±19.5, -21.0±19.8, and -33.5±26.9µg/d) were significantly different among three periods for male (P<0.001 for all); mean values of iodine intake (16.6±3.1, 29.7±2.7, and 48.0±2.7µg/d), and excretion (47.0±9.9, 55.5±8.1, and 75.7±12.4µg/d) were significantly different among three periods for female (P < 0.001 for all). No significant difference was observed among the 3 periods for female in the iodine balance (-30.5±9.3, -25.9±7.3, and -27.6±12.1µg/d). The linear regression equation of iodine excretion on iodine intake was Y=0.979X+37.04 (male) and Y=0.895X+31.48 (female). Compared with stage 2, iodine excretion increments in stage 3 had exceeded the iodine intake increment for men. The ratio of increment was 1.675 for male when the average iodine intake was 52.2µg/d in stage 3. When the iodine excretion increment equaled to the iodine intake increment, the daily iodine intake of men was 47.0µg. CONCLUSION: We have evaluated the iodine requirement of young adults in southern China based on overflow theory. Our results indicate the lower limit of iodine requirement for Chinese young men is 47.0µg/d. The trial was registered at www.chictr.org.cn as ChiCTR1800014877.

Dexamethasone Induces Apoptosis of Embryonic Palatal Mesenchymal Cells Through the GATA-6/Bone Morphogenetic Protein-2/p38 MAPK Pathway.

ABSTRACT: Exposure to dexamethasone (DEX) causes cleft palate at high rates. Our previous studies proved that GATA binding protein 6 (GATA-6)/bone morphogenetic protein-2 (BMP-2) mediated apoptosis is related to DEX-induced cleft palate, but the specific mechanism is still unclear. The goal of this research was to understand the mechanism of apoptosis in cleft palate formation induced by DEX. Palatal mesenchymal cells from mouse embryos on embryonic day 13 were isolated as the experimental group, GATA-6 was silenced by GATA-6 small interfering Ribonucleic Acid (RNA). Cell Counting Kit-8, flow cytometry and Western Blot were applied to detect cell proliferation ability, cell cycle, the proportion of apoptotic cells, and the expression of apoptosis- related proteins of GATA-6 knockdown palatal mesenchymal cells. Further proteins on the BMP-2/Mitogen-activated protein kinase (MAPK) pathways were detected using Western Blot. T results showed that knockdown of GATA-6 by siRNA significantly decreased cell proliferation and increased the expression of apoptosis-related proteins. Bone morphogenetic protein-2/P38 mitogen Activated protein kinase (P38 MARK) pathway proteins decreased significantly among the GATA-6 knockdown group, DEX-cleft palate group and control +DEX groups. The results indicated that the GATA-6/BMP-2/P38 MAPK athway was involved in the apoptosis caused by GATA-6 silencing, which may be the possible mechanism of DEX inducing cleft palate.

Fast charging of lithium-ion batteries at all temperatures.

Fast charging is a key enabler of mainstream adoption of electric vehicles (EVs). None of today's EVs can withstand fast charging in cold or even cool temperatures due to the risk of lithium plating. Efforts to enable fast charging are hampered by the trade-off nature of a lithium-ion battery: Improving low-temperature fast charging capability usually comes with sacrificing cell durability. Here, we present a controllable cell structure to break this trade-off and enable lithium plating-free (LPF) fast charging. Further, the LPF cell gives rise to a unified charging practice independent of ambient temperature, offering a platform for the development of battery materials without temperature restrictions. We demonstrate a 9.5 Ah 170 Wh/kg LPF cell that can be charged to 80% state of charge in 15 min even at -50 °C (beyond cell operation limit). Further, the LPF cell sustains 4,500 cycles of 3.5-C charging in 0 °C with <20% capacity loss, which is a 90× boost of life compared with a baseline conventional cell, and equivalent to >12 y and >280,000 miles of EV lifetime under this extreme usage condition, i.e., 3.5-C or 15-min fast charging at freezing temperatures.

Maternal Mental Health Status and Approaches for Accessing Antenatal Care Information During the COVID-19 Epidemic in China: Cross-Sectional Study.

BACKGROUND: China was the first country in the world to experience a large-scale COVID-19 outbreak. The rapid spread of the disease and enforcement of public health measures has caused distress among vulnerable populations such as pregnant women. With a limited understanding of the novel, emerging infectious disease, pregnant women have sought ways to access timely and trusted health care information. The mental health status of pregnant women during this public health emergency, as well as how they responded to the situation and where and how they obtained antenatal care information, remain to be understood. OBJECTIVE: This study aimed to evaluate the mental health status of pregnant women during the COVID-19 epidemic in China by measuring their perceived stress, anxiety, and depression levels; explore the approaches used by them to access antenatal health care information; and determine their associations with maternal mental health status. METHODS: We conducted a web-based, cross-sectional survey to assess the mental health status of Chinese pregnant women by using the validated, Chinese version of Perceived Stress Scale, Self-Rating Anxiety Scale, and Edinburgh Depression Scale. We also collected information on the various approaches these women used to access antenatal care information during the early stage of the COVID-19 epidemic, from February 5 to 28, 2020. RESULTS: A total of 1873 pregnant women from 22 provinces or regions of China participated in the survey. The prevalence of perceived stress, anxiety, and depression among these participants was 89.1% (1668/1873; 95% CI 87.6%, 90.4%), 18.1% (339/1873; 95% CI 16.4%, 19.9%), and 45.9% (859/1873; 95% CI 43.6%, 48.1%), respectively. Hospitals' official accounts on the Chinese social media platforms WeChat and Weibo were the most popular channels among these pregnant women to obtain antenatal care information during the COVID-19 outbreak. Access to antenatal care information via the hospitals' official social media accounts was found to be associated with a significantly lower risk of perceived stress (adjusted odds ratio [aOR] 0.46, 95% CI 0.30-0.72; P=.001), anxiety (aOR 0.53, 95% CI 0.41-0.68; P<.001), and depression (aOR 0.73, 95% CI 0.59-0.91; P=.005). Access to health care information via hospital hotlines or SMS was found to be significantly associated with a lower risk of anxiety only (OR 0.77, 95% CI 0.60-0.98; P=.04). CONCLUSIONS: During the COVID-19 outbreak in China, pregnant women experienced high levels of perceived stress, anxiety, and depression. During such public health emergencies, mental health care services should be strengthened to reassure and support pregnant women. Specific information targeted at pregnant women, including information on how to cope in an emergency or major disease outbreak, developed and disseminated by health care institutions via social media platforms could be an effective way to mitigate mental health challenges and ensure epidemic preparedness and response in the future.

Geographical distribution and prevalence of mental disorders among healthcare workers in China: A cross-sectional country-wide survey: A cross-sectional study to assess mental disorders of healthcare workers in China.

BACKGROUND: Reliable and detailed nationwide data on the prevalence and distribution of mental disorders among healthcare workers in China during the coronavirus disease 2019 (COVID-19) outbreak are scarce. METHODS: We did a cross-sectional online survey from March 2 to 2 April 2020 and a total of 19,379 healthcare workers from 25 provinces participated. Depression, anxiety and post-traumatic stress disorder (PTSD) were assessed by the Patient Health Questionnaire (PHQ-9), Generalized Anxiety Disorder Scale (GAD-7) and PTSD Checklist for DSM-5 (PCL-5), respectively. RESULTS: The age-standardized prevalence of depression, anxiety and PTSD was 15.5%, 12.7% and 5.2%, respectively. Frontline workers had higher prevalence estimates than non-frontline workers (depression: 18.2% vs. 13.9%; anxiety: 14.7% vs. 11.6%; PTSD: 6.1% vs. 4.6%). Subgroups who were nurses, were married or had dependent children reported higher prevalence of depression, anxiety and PTSD. Despite of the large variations, the prevalence of mental disorders was lowest in East China, followed by Middle China, and highest in West China. CONCLUSION: Healthcare workers faced enormous stress not only from the direct risk presented by the COVID-19 outbreak, but also from the profound changes in their professional practice. Prevalence of adverse psychological outcomes has a significant association with geographically distribution of health resources and regional economic level. Sufficient medical resource may be a protective factor to mental health condition of healthcare personnel when such a public health emergency happened.