[Incidence of common gene mutations in early-onset colorectal cancer and the association with cancer survival: a meta-analysis]

Objective: The incidence of early-onset colorectal cancer (EOCRC) is increasing globally; however, the molecular characteristics and prognosis of sporadic EOCRC are unclear. In this systematic review and meta-analysis, we aimed to investigate the incidence of gene mutations and their association with cancer survival in sporadic EOCRC, focusing on six common gene mutations (TP53, BRAF, KRAS, NRAS, PTEN, and APC). Methods: Ovid Embase and Ovid Medline electronic databases were searched for studies involving patients with sporadic EOCRC (i.e., diagnosed with colorectal cancer before the age of 50 years and with no evidence of hereditary syndromes predisposing to colorectal cancer). The included articles were evaluated using quality assessment tools. Meta-analysis was performed using random-effects and fixed-effects models. Cochran's Q statistic and the I2 index were used to assess heterogeneity. The incidence of the six common gene mutations listed above in sporadic EOCRC and their association with cancer survival were evaluated. Results: (1) Incidence of specific gene mutations in sporadic EOCRC. A total of 34 articles were included in this meta-analysis. The incidence of APC gene mutation was 36% (from 13 articles, 95%CI: 19%-55%, P=0.043); of KRAS gene mutation 30% (from 26 articles, 95%CI: 24%-35%, P=0.190); of BRAF gene mutation 7% (from 18 articles, 95%CI: 5%-11%, P=0.422); of NRAS gene mutation 4% (from five articles, 95%CI: 3%-5%, P=0.586); of PTEN gene mutation 6% (from six articles, 95%CI: 4%-10%, P=0.968); and of TP53 gene mutation 59% (from 13 articles, 95%CI: 49%-68%, P=0.164). (2) Association between gene mutations and survival in sporadic EOCRC. A total of six articles were included in this meta-analysis. Compared with wild-type BRAF, mutant BRAF was significantly associated with increased overall mortality risk in patients with EOCRC (pooled HR=2.85, 95%CI: 1.45-5.60, P=0.002). Subgroup analysis showed that the incidence of BRAF gene mutation was higher in Eastern than in Western countries, whereas the incidence of TP53, KRAS, NRAS, and APC gene mutations was lower. There was no significant difference in the incidence of PTEN gene mutation between different regions. Conclusion: Compared with colorectal cancer occurring in the general population, the incidence of APC and KRAS mutations is lower in EOCRC, whereas the incidence of TP53 mutation remains consistent. BRAF mutation is associated with increased overall mortality risk in patients with EOCRC.

[Pollution Characteristics，Sources，and Secondary Generation of Organic Acids in PM2.5 in Zhengzhou]

Organic acids in atmospheric particulate matter are widely involved in various physical and chemical reactions in the atmosphere and contribute greatly to the formation of secondary organic aerosols and haze pollutions. Therefore， the concentration distribution characteristics， sources， and secondary formation of organic acids in particulate matter are of great significance for further investigation of organic aerosols and their secondary transformation. Fine particulate matter （PM2.5） samples were collected in Zhengzhou， and three types of organic acids， including dicarboxylic acids， fatty acids， and resin acids， were analyzed to explore their species distribution， seasonal variations， source contribution， and secondary generation. Malonic acid （di-C3） and succinate acid （di-C4） were the most abundant in the identified dicarboxylic acids， which showed obvious seasonal variations in the order of summer > autumn > winter > spring. Fatty acids had the highest concentration in winter and the lowest concentration in spring， showing obvious bimodal advantages， with the most abundant compounds being palmitic acid and stearic acid （C18）. Principal component analysis and multiple linear regression （MLR） were used to analyze the source of organic acids in PM2.5 in Zhengzhou； the results showed that 35% of the organic acids came from combustion and traffic sources， 24% from cooking sources， 23% from secondary formation， and 17% from natural sources. The ratios of the selected marker species （i.e.， di-C3 / di-C4， F/M， and C18：1 / C18） were used as tracers for the secondary formation of the organic aerosol and its aging process. The results showed that the photochemical reaction was intense in summer， and the proportion of organic aerosol aging or secondary production was high， whereas the photochemical reaction was weak in winter， and the aging degree of organic aerosol was low. Correlation analysis and MLR were used in combination to quantify the relative contribution of gas-phase oxidation and liquid-phase oxidation to dicarboxylic acid formation， and the results showed that gas-phase oxidation played a dominant role in the sampling period （accounting for 58%）， especially in summer （61%）.

[Pollution Characteristics，Source Analysis，and Activity Analysis of Atmospheric VOCs During Winter and Summer Pollution in Zhengzhou]

In order to study the pollution characteristics of volatile organic compounds （VOCs）， continuous monitoring of VOCs in two pollution processes was conducted in June and December 2021 in Zhengzhou. Combined with meteorological conditions， the pollution characteristics， source contributions， and reactivity of VOCs in winter and summer were compared and analyzed. The results showed that the volume fraction of atmospheric VOCs in two episodes were （27.92±12.68）×10-9 and （24.30±5.93）×10-9， respectively. The volume fraction of atmospheric VOCs in the haze pollution process in winter was larger than that in the ozone pollution process in summer. The analysis results of winter sources were as follows： industrial source （27.0%）， motor vehicle source （22.5%）， combustion source （20.1%）， solvent use source （16.3%）， and oil and gas volatilization source （14.1%）. The analysis results of summer sources were as follows： motor vehicle source （24.8%）， industrial source （24.1%）， solvent source （17.4%）， oil and gas volatilization source （14.2%）， combustion source （11.2%）， and plant source （8.4%）. The results of the smog production model showed that the proportion of days in the synergistic control zone of VOCs during the two pollution processes in summer （66.7%） was smaller than that in winter （100.0%）. The secondary reaction activity results showed that the average ·OH loss rate （L·OH） values in winter and summer were 4.12 s-1 and 4.75 s-1， respectively. The average ozone formation potential （OFP） values in summer were 108.36 μg·m-3. The olefins were dominant in the top ten species due to L·OH and OFP contributions in summer. The total SOAFP values in winter in Zhengzhou were 54.38 μg·m-3. Among the top ten species contributing to SOAFP in winter， nine were aromatic hydrocarbons.

[Characteristics of Secondary Inorganic Ions in PM2.5 and Its Influencing Factors in Summer in Zhengzhou]

Nitrate (NO3-), sulfate (SO42-), and ammonium (NH4+) are important components of PM2.5, and studying their characteristics and influencing factors is essential for the continuous improvement of air quality. A series of online instruments were used to analyze the chemical components of PM2.5 in Zhengzhou in the summer of 2020. The results showed that the average ρ(PM2.5) was (28 ±13) μg·m-3, showing a daily variation characteristic of high at night and low during the day. The main concentrations of NO3-, SO42-, and NH4+ were (7.8 ±6.7), (7.2 ±3.7), and (5.5 ±3.1) μg·m-3, accounting for 22%, 21%, and 16% in PM2.5, respectively. The proportions of NO3- (27%) and SO42- (23%) in PM2.5, respectively, increased with the increase in PM2.5 and O3 concentration. In addition, the proportions of NO3- and NH4+ increased under low wind speed, high humidity, low temperature, and rainfall conditions. Moreover, the proportion of NO3- showed a daily variation characteristic of high at night and low during the day, whereas the opposite was true for SO42-. The gas-particle partitioning process of NH4NO3 was the main factor affecting the concentrations of NO3- and NH4+ in PM2.5. Low temperature, high humidity, and high aerosol water content concentrations favored the partitioning of HNO3 and NH3 to the particulate phase. High pH also favored the partitioning of gas-phase HNO3 to NO3-; however, it was not conducive to the partition of NH3 to NH4+. These trends partially explained the increase in the concentration and proportion of NO3- in PM2.5 under different scenarios.

Carnosol ameliorated cancer cachexia-associated myotube atrophy by targeting P5CS and its downstream pathways

Introduction: Carnosol exhibited ameliorating effects on muscle atrophy of mice developed cancer cachexia in our previous research. Method: Here, the ameliorating effects of carnosol on the C2C12 myotube atrophy result from simulated cancer cachexia injury, the conditioned medium of the C26 tumor cells or the LLC tumor cells, were observed. To clarify the mechanisms of carnosol, the possible direct target proteins of carnosol were searched using DARTS (drug affinity responsive target stability) assay and then confirmed using CETSA (cellular thermal shift assay). Furthermore, proteomic analysis was used to search its possible indirect target proteins by comparing the protein expression profiles of C2C12 myotubes under treatment of C26 medium, with or without the presence of carnosol. The signal network between the direct and indirect target proteins of carnosol was then constructed. Results: Our results showed that, Delta-1-pyrroline-5-carboxylate synthase (P5CS) might be the direct target protein of carnosol in myotubes. The influence of carnosol on amino acid metabolism downstream of P5CS was confirmed. Carnosol could upregulate the expression of proteins related to glutathione metabolism, anti-oxidant system, and heat shock response. Knockdown of P5CS could also ameliorate myotube atrophy and further enhance the ameliorating effects of carnosol. Discussion: These results suggested that carnosol might ameliorate cancer cachexia-associated myotube atrophy by targeting P5CS and its downstream pathways.

Boosting the photoelectrochemical performance of bismuth vanadate photoanode through homojunction construction

The photoelectrochemical (PEC) performance of bismuth vanadate (BiVO₄) suffers from sluggish charge mobility and substantial charge recombination losses due to its intrinsic defect. To rectify the problem, we developed a novel approach to prepare an n-n⁺ type II BVO_ac-BVO_al homojunction with staggered band alignment. This architecture involves a built-in electric field that facilitating the electron-hole separation at the BVO_ac/BVO_al interface. As a result, the BVO_ac-BVO_al homojunction shows superior photocurrent density up to 3.6 mA/cm² at 1.23 V vs. reversible hydrogen electrode (RHE) with 0.1 M sodium sulfite as the hole scavenger, which is 3 times higher than that of the single-layer BiVO₄ photoanode. Unlike the previous efforts that modifying the PEC performance of BiVO₄ photoanodes through incorporating heteroatoms, the highly-efficient BVO_ac-BVO_al homojunction was achieved without incorporating any heteroatoms in this work. The remarkable PEC activity of the BVO_ac-BVO_al homojunction highlights the tremendous importance of reducing the charge recombination rate at the interface by constructing the homojunction and offers an effective strategy to form the heteroatoms-free BiVO₄ thin film as an efficient photoanode material for practical PEC applications.

[Changes in Secondary Inorganic Ions in PM2.5 at Different Pollution Stages Before and After COVID-19 Control]

To investigate the change characteristics of secondary inorganic ions in PM_2.5 at different pollution stages before and after COVID-19, the online monitoring of winter meteorological and atmospheric pollutant concentrations in Zhengzhou from December 15, 2019 to February 15, 2020 was conducted using a high-resolution (1 h) online instrument. This study analyzed the causes of the haze process of COVID-19, the diurnal variation characteristics of air pollutants, and the distribution characteristics of air pollutants at different stages of haze.The results showed that Zhengzhou was mainly controlled by the high-pressure ridge during the haze process, and the weather situation was stable, which was conducive to the accumulation of air pollutants. SNA was the main component of water-soluble ions, accounting for more than 90%. Home isolation measures during COVID-19 had different impacts on the distribution characteristics of air pollutants in different haze stages. After COVID-19, the concentration of PM_2.5 in the clean, occurrence, and dissipation stages increased compared with that before COVID-19 but significantly decreased in the development stage. The home isolation policy significantly reduced the high value of PM_2.5. The concentrations of NO₂, SO₂, NH₃, and CO were the highest in the haze development stage, showing a trend of first increasing and then decreasing. The concentration of O₃ was lowest in the pre-COVID-19 development stage but highest in the post-COVID-19 development stage. The linear correlation between[NH₄⁺]/[SO₄^2-] and[NO₃^-]/[SO₄^2-] at different time periods before and after COVID-19 was strong, indicating that the home isolation policy of COVID-19 did not change the generation mode of NO₃^-, and the corresponding reaction was always the main generation mode of NO₃^-. The correlation between[excess-NH₄⁺] and[NO₃^-] was high in different periods before COVID-19, and NO₃^- generation was related to the increase in NH₃ or NH₄⁺ in the process of PM_2.5 pollution in Zhengzhou.

[Evaluation of Changes in PM2.5 Exposure Concentration and Health Risk for Urban Resident in Zhengzhou Based on High Spatial Resolution Grids]

In recent years, complex air pollution with the characteristic pollutant of PM_2.5 has remained serious in China. Long term exposure to PM_2.5 might harm residential health and can increase premature death from specific diseases. The annual average concentration of PM_2.5 in Zhengzhou was much higher than the national secondary standard, which has an extremely negative impact on the health of residents. Based on the high spatial resolution grids of population density established through web-crawling and outdoor monitoring concentrations and urban residential emissions used to evaluate PM_2.5 exposure concentration, the exposure concentration of PM_2.5 for urban residents of Zhengzhou was assessed, considering both indoor and outdoor exposures. Relevant health risks were quantified with the integrated exposure-response model. Finally, the contributions of various reducing measures and different standards of air quality to the decreases in PM_2.5 exposure concentration were analyzed. The results showed that in 2017 and 2019, the time weighted exposure concentrations of PM_2.5 for Zhengzhou's urban residents were 74.06 μg·m^-3 and 60.64 μg·m^-3, respectively, which was decreased by 18.12%. In addition, the mass fractions of the indoor exposure concentrations in the time weighted exposure concentrations were 83.58% and 83.01%, and its contribution to the drop of the time weighted exposure concentrations was 84.06%. In 2017 and 2019, the numbers of premature deaths attributed to PM_2.5 exposures for urban residents of Zhengzhou over the age of 25 were 13285 and 10323, respectively, showing a 22.30% decrease. By using these comprehensive measures, PM_2.5 exposure concentration for Zhengzhou's urban residents could be reduced by 86.23% at most, and 8902 premature deaths could be avoided.

Higher-order Rayleigh-quotient gradient effect on electron correlations

The incomplete understanding of electron correlation is still profound due to the lack of exact solutions of the Schrödinger equation of many electron systems. In this work, we present the correlation-induced changes in the calculated many-electron systems beyond the standard residual. To locate the minimum of the Rayleigh quotient, each iteration is to seek the lowest eigenpairs in a subspace spanned by the current wave function and its gradient of the Rayleigh-quotient as well as the upcoming higher-order residual. Consequently, as the upcoming errors can be introduced and circumvented with the search in the higher-order residual, a concomitant improved performance in terms of number of iterations, convergence rate, and total elapsed time is very significant. The correlation energy components obtained with the original residual are corrected with the higher-order residual application, satisfying the correlation virial theorem with much improved accuracy. The comparison with the original residual, the higher-order residual significantly improves the electron binding, favoring the localization of electrons’ distribution, revealed with the increasing peak of the distribution and correlation function and the reduced interelectron distance and its angle.

[Variation Characteristics and Source Apportionment of Atmospheric VOCs at Multi-sites in Zhengzhou]

From July 2020 to June 2021, monthly offline sampling of atmospheric VOCs was carried out and analyzed at three urban sites and one suburban site in Zhengzhou. Then, the volume fraction levels, composition characteristics, reactivity, and source apportionment of atmospheric VOCs were discussed. The results showed that the volume fraction of atmospheric VOCs in Zhengzhou was (37.50±14.30)×10^-9 during the sampling period, and the proportion of components was represented by alkanes (33%)>OVOCs (24%)>halogenated hydrocarbons (23%)>aromatic hydrocarbons (8%)>alkenes (7%)>alkynes (4%)>sulfides (1%). The seasonal variation characteristics were winter>autumn>summer>spring, and the monthly average value of VOCs had the highest value in January and the lowest value in May; the spatial variation characteristics were Zhengzhou University (ZD)>Jiancezhan (JCZ)>Jingkaiqu (JKQ)>Gangli Reservoir (GLR). The average·OH loss rate (L_·OH) was 4.24 s^-1, and the average ozone formation potential (OFP) was 172.27 μg·m^-3; the top ten species of L_·OH and OFP at each site and in each season were dominated by alkenes, OVOCs, and aromatic hydrocarbons. The results of positive matrix factorization (PMF) showed that the main sources of VOCs were vehicle emissions (28%), solvent utilization (24%), industrial emissions (24%), and oil and gas volatilization (19%) and plant emissions (5%).

Self-isomerization of nearly planar superatoms formed by actinide embedded gold clusters

First-principles calculations show a self-isomerization process of the nearly planar superatom, in which the maximum energy difference between different extreme points is below 0.1 eV and a crossing between singlet and triplet states is also involved. Further UV-Vis spectra reveal a correlation between the spectra and structures caused by self-isomerization.

[Differences in PM2.5 Components Between Urban and Rural Sites During Heavy Haze Event in Northern Henan Province]

In recent years, the Beijing-Tianjin-Hebei region and its surrounding areas have experienced multiple haze pollution processes. Owing to the limitation of observational instruments, there has not been a comparative study of haze pollution between urban and rural areas in northern Henan province. A series of high-time-resolution instruments were used during a regional heavy pollution process (January 12-25, 2018) at two urban sites and three rural sites. The results showed that SO₄^2-, NO^-₃, and NH⁺₄ (SNA) were the components with the highest proportion in PM_2.5 at the five sites during the haze event with a range of 53%-63%, of which nitrate was the most important, accounting for 24%-32%, followed by sulfate, ranging from 13%-17%. Compared with urban sites, rural sites were more affected by organic matter, especially at night. With the aggravation of pollution, the proportion of SNA increased, reaching 67% during periods of heavy pollution. When the area was affected by the air mass transported from the south, the proportion of NO^-₃ in PM_2.5 increased, and when the area was affected by the air transport in the north, the proportions of SO₄^2- and organic matter increased. Ammonium nitrate was the most important component that led to the decrease in atmospheric visibility during the haze process. Moreover, the contributions of ammonium nitrate and ammonium sulfate at the urban sites were higher than those at the rural sites. To summarize, there were significant differences in PM_2.5 components between the urban and rural sites. Urban areas need to continue to strengthen the reduction in gaseous precursors, and rural areas need to pay attention to the sources of carbonaceous aerosol.

Spent LiFePO4: An old but vigorous peroxymonosulfate activator for degradation of organic pollutants in water

Iron-based catalysts have been demonstrated to activate peroxymonosulfate (PMS) to generate reactive radicals, which is however limited by their complex preparation process, high costs and inefficiency for practical applications. Herein we obtain spent LiFePO₄ (SLFP), with powerful catalytic capacity by a simple one-step treatment of the retired LiFePO₄ cathode material, for PMS activation to decontaminate organic pollutants. Lithium defects and oxygen vacancies in SLFP play critical roles for PMS utilization, further confirmed by density functional theory (DFT) calculations. SLFP materials rapidly adsorb PMS, and the surface PMS is activated by Fe(II) to generate radicals, with ^•OH playing a major role for the degradation of organics after multi-step reactions. The SLFP/PMS process is finally validated for ability to remove organic contaminants and potential environmental application.

Charge Transfer Doping of Carbon Nitride Films through Noncovalent Iodination for Enhanced Photoelectrochemical Performance: Combined Experimental and Computational Insights

To improve the photoelectrochemical (PEC) performance of photocatalysts, the doping strategy through covalent functionalization is often adopted to adjust material electronic structures. By contrast, this work demonstrates that the noncovalent interaction in the case of iodinated graphitic carbon nitride (g-CN) film can also enhance the PEC performance. Through a facile synthesis method of rapid thermal vapor condensation (RTVC), the prepared iodinated g-CN film shows a significantly improved photocurrent density (38.9 µA cm^-2 ), three times that of pure g-CN film (13.0 µA cm^-2 ) at 1.23 V versus reversible hydrogen electrode. Computations reveal that the noncovalent attachment of iodine anion (I^- ) on g-CN plays a crucial role in modulating the bandgap states and broadening of the visible-light absorption range as well as the charge carrier separation with the photo-induced hole confined to I^- and electron to g-CN film. The fully filled valence orbitals (4d¹⁰ 5s² 5p⁶ ) of I^- determine its noncovalent attachment on the g-CN film and so do the iodine species of I₃ ^- , I₅ ^- , etc. This work offers a favorable synthesis method to achieve efficient doping through noncovalent charge transfer between thin film and certain dopants and provides a useful modification strategy for the establishment of multi-channel transportation of charge carriers in general photocatalysts.

Surface-Mounted Dipolar Molecular Rotors Driven by External Electric Field, As Revealed by Torque Analyses

Driven by a high-speed rotating electric field (E-field), molecular motors with polar groups may perform a unidirectional, repetitive, and GHz frequency rotation and thus offer potential applications as nanostirrers. To drive the unidirectional rotation of molecular motors, it is crucial to consider factors of internal charge flow, thermal noise, molecular flexibility, and so forth before selecting an appropriate frequency of a rotating E-field. Herein, we studied two surface-mounted dipolar rotors of a "caltrop-like" molecule and a "sandwich" molecule by using quantum-mechanical computations in combination with torque analyses. We find that the rotational trend as indicated by the magnitude and the direction of torque vectors can sensitively change with the lag angle (α) between the dipolar arm and the E-field. The atomic charges timely flow within the molecule as the E-field rotates, so the lag angle α must be kept in particular intervals to maintain the rotor's unidirectional rotation. The thermal effect can substantially slow down the rotation of the dipolar rotor in the E-field. The flexible dipolar arm shows a more rigid geometry in the E-field with higher rotation speed. Our work would be useful for designing E-driven molecular rotors and for guiding their practical applications in future.

Carnosol attenuated atrophy of C2C12 myotubes induced by tumour-derived exosomal miR-183-5p through inhibiting Smad3 pathway activation and keeping mitochondrial respiration

Cancer-derived exosomes are involved in the development of cancer cachexia. Carnosol, which exhibited ameliorating effects on cancer cachexia of C26 tumour-bearing mice in our previous study, alleviated atrophy of C2C12 myotubes induced by exosomes of C26 tumour cells in the present study. MiR-183-5p was found to be rich in C26 cells and C26 exosomes, and miR-183-5p mimic could directly induce atrophy of C2C12 myotubes. Carnosol at 5 to 20 μM could dose-dependently ameliorate the myotube atrophy induced by miR-183-5p. Four-and-a-half LIM domain protein 1 (FHL1) was shown to be the direct target of miR-183-5p. Increase in myostatin, p-Smad3, MuRF-1, Atrogin-1, HIF-1α, p-STAT3 and decrease in mitochondrial respiration were also induced by miR-183-5p mimic in C2C12 myotubes. Carnosol could not affect the decrease in FHL-1 and the activation of STAT3 pathway but could significantly alleviate the increase in myostatin, p-Smad3, MuRF-1, Atrogin-1 and the decrease in mitochondrial respiration induced by miR-183-5p. The protective effects of carnosol on myotubes against atrophy of C2C12 myotubes induced by miR-183-5p, based on both its inhibiting effects on MuRF-1 and Atrogin-1-mediated protein degradation and its ability of keeping the mitochondrial respiration, might contribute to its ameliorating effects on cancer cachexia.

[One-year Simulation of Air Pollution in Central China, Characteristics, Distribution, Inner Region Cross-transmission, and Pathway Research in 18 Cities]

Air pollution in Henan province is serious and is significantly impacted by pollution transmission and interactions with surrounding areas. The emission sources in 18 cities in Henan province were labeled and applied to the WRF-CMAQ traceability model for simulation in January, April, July, and October of 2017. The pollutant distribution results showed that due to the combined influence of emissions and meteorology, the concentrations of PM_2.5, NO₂, and SO₂ in Henan province were the highest in winter and the lowest in summer. The seasonal variation in O₃-8h concentration was the highest in summer, followed by spring, and the lowest in winter. There was a large difference in pollutant concentrations between different seasons. The average concentrations of PM_2.5, NO₂, and SO₂ in winter in Henan province were 4.17, 4.12, and 6.24 times those in summer, respectively, whereas the concentration of O₃-8h in summer was 2.24 times that in winter. Since PM_2.5, NO₂, and SO₂ are closely related to primary emissions and have a certain homology, the distributions of high values of these three pollutants were higher in the north and lower in the south, and the seasonal trends were more consistent. The seasonal distribution of O₃-8h varied widely, with high O₃-8h values mainly distributed in the northeastern region of Henan province in summer, when meteorological conditions contributed to O₃ production; in winter, spring, and autumn, high O₃-8h values were mainly distributed in the southern part of Henan province due to the suppression of meteorological conditions and NO_x consumption. The results of the study on the transport of pollutants showed that extra-provincial transport and natural sources contributed the most to the concentrations of PM_2.5, O₃-8h, NO₂, and SO₂ in winter, with 36.20%-72.32%, 77.96%-96.08%, 49.45%-78.80%, and 59.05%-88.85%, respectively. When considering only local emissions and intra-provincial transmission, the contributions of emissions to local concentrations of the four pollutants in summer were the highest in all cities of Henan province. The contributions of intra-provincial transmission to PM_2.5 and O₃-8h in spring were the largest, with 25.63%-74.69% and 30.21%-80.01%, respectively, and the contributions of intra-provincial transmission to NO₂ and SO₂ in winter were larger, with 26.02%-76.96% and 20.30%-82.34%. The transmission paths of PM_2.5, NO₂, and SO₂ were more similar in Henan province, with more transmission from north to south in winter, from west to east and southwest to northeast in spring, from southwest to northeast in summer, and from north to south in autumn; however, the transmission of PM_2.5 was more complicated. The O₃-8h transport path was more different from the others, especially in autumn when pollutants were mostly transported from north to south, but the O₃-8h transport path from southwest to northeast was obvious.

[Influence of COVID-19 Prevention and Control Measures on PM2.5 Concentration, Particle Size Distribution, Chemical Composition, and Source in Zhengzhou, China]

The COVID-19 lockdown was a typical occurrence of extreme emission reduction, which presented an opportunity to study the influence of control measures on particulate matter. Observations were conducted from January 16 to 31, 2020 using online observation instruments to investigate the characteristics of PM_2.5 concentration, particle size distribution, chemical composition, source, and transport before (January 16-23, 2020) and during (January 24-31, 2020) the COVID-19 lockdown in Zhengzhou. The results showed that the atmospheric PM_2.5 concentration decreased by 4.8% during the control period compared with that before the control in Zhengzhou. The particle size distribution characteristics indicated that there was a significant decrease in the mass concentration and number concentration of particles in the size range of 0.06 to 1.6 μm during the control period. The chemical composition characteristics of PM_2.5 showed that secondary inorganic ions (sulfate, nitrate, and ammonium) were the dominant component of PM_2.5, and the significant increase in PM_2.5 was mainly owing to the decrease in NO₃^- concentration during the control period. The main sources of PM_2.5 identified by the positive matrix factorization (PMF) model were secondary sources, combustion sources, vehicle sources, industrial sources, and dust sources. The emissions from vehicle sources, industrial sources, and dust sources decreased significantly during the control period. The results of analyses using the backward trajectory method and potential source contribution factor method indicated that the effects of transport from surrounding areas on PM_2.5 concentration decreased during the control period. In summary, vehicle and industrial sources should be continuously controlled, and regional combined prevention and control should be strengthened in the future in Zhengzhou.

[Trend Changes in Ozone Pollution and Sensitivity Analysis of Ozone in Henan Province]

Based on air quality station data and satellite remote sensing data, the interannual variation characteristics and seasonal variation trends of near-surface ozone (O₃) in Henan province were studied, and the variation in O₃ sensitivity was analyzed. The results showed that the O₃ concentration near the surface of Henan province increased first and then decreased from 2015 to 2020. The highest O₃ concentration was found in 2018, and the annual mean of the maximum daily 8 h moving mean (MDA8) of O₃ was 110.70 μg·m^-3. The difference in MDA8 values among different stations gradually decreased. From 2015 to 2020, the average monthly MDA8 in Henan province showed an upward trend, with a growth rate of 2.46 μg·(m³·a)^-1. According to the MK trend test, except for in Luohe, Nanyang, and Pingdingshan, the rising trend in other cities was significant (P<0.05). The concentration of MDA8 in the four seasons also showed an increasing trend during the 6 years as follows:autumn (19.31%)>winter (17.09%)>spring (16.82%)>summer (7.24%). From 2015 to 2019, the high value of tropospheric NO₂ was concentrated in the northwest of Henan province, and the concentration showed a decreasing trend with a decreasing rate of 0.34×10¹⁵ molecules·(cm²·a)^-1, whereas the tropospheric HCHO showed a slow rising trend with an annual growth rate of 0.19×10¹⁵ molecules·(cm²·a)^-1, with a higher concentration in the northern urban area. The O₃ sensitivity control area from 2015 to 2019 showed that most of the eastern part of Henan province belonged to the VOCs limited category.

[Characteristics and Source Apportionment of Vehicular VOCs Emissions in a Tunnel Study]

To explore the emission characteristics of volatile organic compounds (VOCs) from vehicular exhaust sources and evaporative sources with ethanol gasoline (E10) as the main fuel, VOCs sampling campaigns were carried out in the north third ring tunnel of Zhengzhou city for two consecutive weeks in December 2019. In addition, the characteristics of traffic flow and environmental information were also monitored in the tunnel. Firstly, 106 VOCs were quantified using gas chromatography/mass spectrometry (GC/MS), and then source apportionment of VOCs in the tunnel was carried out using a positive matrix factorization (PMF5.0)-chemical mass balance (CMB8.2) composite model. Finally, the ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) of vehicle exhaust sources and evaporative sources were analyzed using the maximum incremental reactivity (MIR) and fractional aerosol coefficient (FAC). The results showed that ρ(VOCs) in the tunnel was (2794.5±147.4) μg·m^-3 during the experiment, among which halogenated hydrocarbons[(32.4±2.0)%] accounted for the highest proportion, followed by aromatic hydrocarbons[(27.5±0.6)%] and alkanes[(23.3±0.8)%]. Source apportionment of vehicular VOCs showed that exhaust emissions (62.5%)>evaporative emissions (37.5%), whereas the contribution of OFP was that exhaust emissions (71.9%)>evaporative emissions (28.1%), and the contribution of SOAFP was that exhaust emissions (75.8%)>evaporative emissions (24.2%). The dominant components of OFP in evaporative sources were m,p-diethylbenzene, isoprene, and trans-2-pentene, whereas m,p-diethylbenzene, m,p-xylene, and 1,2,3-trimethylbenzene were the dominant components of SOAFP. The major components of OFP in exhaust sources were m,p-xylene, 1,2,4-trimethylbenzene, and 1,3,5-trimethylbenzene, whereas m,p-xylene, m,p-diethylbenzene, and 1,3,5-trimethylbenzene were the dominant components of SOAFP. In regions where ethanol gasoline is used, special attention should be paid not only to the exhaust emissions control but also to strengthening the emissions reduction of VOCs from vehicle evaporative sources, especially the high active components such as aromatic hydrocarbons and alkenes.

[Concentration, Source, and Health Risk Assessment of PM1 Heavy Metals in Typical Pollution Processes in Zhengzhou]

Heavy metal elements in particulate matter can cause adverse effects on human health, and the smaller the particle size, the greater the harm. A total of 16 heavy metal elements (Al, Si, K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Ba, Pb, and Cd) in PM₁ were continuously determined by an online heavy metal observation instrument in Zhengzhou city from January 7 to 25, 2021. The results showed that ρ(K) concentration was the highest during the observation period (0.62 μg·m^-3). According to pollutant concentration and meteorological characteristics, the observation period was divided into clean days, dust days, and haze days. The contribution of heavy metal pollution characteristics and health risk assessment in atmospheric PM₁ was different under different pollution processes. The US EPA health risk assessment method was used to assess the health risks of heavy metals, and the enrichment factor method and positive matrix factorization (PMF) were used to analyze the sources of heavy metals. The influence of the transmission was evaluated by using the concentration-weighted trajectory (CWT) method and the backward trajectory method. The results show that the enrichment factors of Zn, As, Se, Pb, and Cd were more than 100 under different pollution processes, which were greatly affected by human activities. During the sampling period, the main sources of heavy metals were industrial sources, coal/biomass sources, motor vehicle sources, and dust sources. The results of the health risk assessment were substituted into PMF analysis, and it was found that industrial sources were the main contributing sources of carcinogenic and non-carcinogenic health risks during cleaning days, dust days, and haze days, and the carcinogenic risk of heavy metal elements in PM₁ in this region for adults exceeded that for children. CWT and backward trajectory methods revealed that regional transmission was one of the main factors affecting local health risks.

Role of the A-Element in the Structural, Mechanical, and Electronic Properties of Ti3AC2 MAX Phases

Combining metallic and ceramic properties, and as precursors for MXenes, MAX phases have attracted extensive attention. In recent years, A-element substitution has been demonstrated as an effective scheme to enrich the MAX family. To explore more possible MAX members, the structural, mechanical, and electronic properties and stabilities of 31 Ti₃AC₂ (A = Al, Si, P, S, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Os, Ir, Pt, Au, Hg, TI, Pb, Bi, and Po) configurations are investigated in this work. Moreover, the interfacial strength implicating the possibility of exfoliating MAX into MXenes is examined. The A-element plays a crucial role in the lattice parameters and mechanical strength of Ti₃AC₂, and their variations are well explained by the synergistic effects of d-d and p-d hybridizations between the valence orbitals of Ti and A. Ti₃SC₂ presents the largest Young's modulus of 360 GPa, which is 6.82% higher than that in the well-studied Ti₃SiC₂. Ti₃SbC₂ is a mechanical quasi-isotropic configuration. After checking the mechanical, dynamical, and thermodynamic stability, Ti₃AC₂ (A = Al, Si, P, S, Ga, Ge, As, Cd, In, Sn, Sb, Au, Hg, Pb, TI, and Po) are stable, while Ti₃AC₂ (A = Fe, Co, Zn, Se, Ru, Rh, Pd, Ag, Te, Ir, Pt, and Bi) are metastable. Compared to Ti₃AlC₂, Ti₃AC₂ (A = Ag, Sb, Te, Bi, and Po) exhibit much lower interfacial strength in Ti-A interfaces and larger ratios between the interfacial strengths of neighboring Ti-C and Ti-A interfaces. This implies that these configurations are promising precursors for the synthesis of Ti₃C₂T_x (T_x denotes surface groups) with a large flake size. All of the configurations are metallic, and Ti₃AC₂ (A = Fe and Co) are magnetic. Based on the phonon dispersion and electronic structure, these Ti₃AC₂ configurations might have potential applications in phononic crystals and topological materials.

[Simulation Analysis of the Impact of COVID-19 Pandemic Control on Air Quality in Henan Province based on Machine Learning Algorithm]

To reduce the risks of COVID-19 on society and the health of the general public, necessary prevention and control measures were implemented throughout China in 2020. Consequently, air quality was greatly improved due to lower emissions. However, the improvement of air quality could also be closely related to meteorological conditions. During quarantine (January 27 to February, 2020), reductions were observed in the concentration of all air pollutants in Henan Province (PM_2.5, PM₁₀, SO₂, CO, and NO₂ decreased by 36.89%, 34.18%, 19.43%, 29.85%, and 58.51%, respectively) relative to measurements taken from January 1 to 26, 2020. The only exception was for the concentration of O₃, which increased by 69.64%. This study evaluates the importance of meteorological conditions in air pollution, through simulation with a long-and-short-term memory network (LSTM) and a machine learning algorithm. Results show that meteorological conditions play a crucial role in air pollutant formation. Given favorable meteorological factors, the concentrations of pollutants could be reduced by 15%-30%, while the reduction due to anthropogenic emission control ranges from 6%-40%. During the epidemic, meteorological conditions and human emissions accounted for 34.84% and 34.81% of the increase in O₃ concentration, respectively. The results show that primary pollutant concentrations are more sensitive to the intensity of anthropogenic emissions. However, secondary pollutants are more dependent on meteorological factors. Furthermore, a nonlinear relationship has been identified between O₃ concentration and to emission intensity. Further investigation into the causes of the rise in O₃ concentration is necessary to gain a greater understanding and better control of particulate matter and O₃ pollution.

[Vehicle Air Pollutant Emission Inventory and Characterization in Henan Province from 2016 to 2019]

Based on the collected urban motor vehicle activity ownership and traffic flow of highways, combined with the mileage and source profiles of VOCs, using the emission factor method, we established high-resolution emission inventories from 2016 to 2019 for urban and 2016-based highway motor vehicles, respectively, in Henan Province, China. The results showed that gasoline vehicles, particularly minibuses and ordinary motorcycles, were the main contributors of CO, VOCs, and NH₃, whereas heavy-duty and light-duty diesel trucks emitted SO₂, NO_x, and PM. Vehicles with China 1, China 3, and China 4 emission standards contributed significantly to pollutant emissions in the fleet. The temporal variation in traffic flow was consistent with the changes in freight and passenger traffic, with higher coefficients of variation for highways from August to October and the lowest in November. The weekly and daily changes in urban trunk roads showed distinct weekend effects and clear double-peak features, respectively. High-value emission areas were concentrated in urban centers with dense transport networks and high traffic volumes and on roads radiating outward from urban areas. The Lianhuo Expressway and the Beijing-Hong Kong-Macau Expressway were high-emission roads. Light-duty gasoline vehicles made the largest contribution to the ozone formation potential (OFP) of VOCs from motor vehicles. Five species, such as ethylene and propylene, contributed significantly to VOC emissions and OFP. The average annual growth rate of vehicle ownership from 2016 to 2019 was 5.7%. Compared with 2016, VOC emissions increased by 2.8% in 2019, whereas emissions of other pollutants showed decreasing trends of different degrees, with decreases of 76.3%, 51.7%, 50.3%, 43.1%, 16.7%, and 5.9% for SO₂, PM_2.5, PM₁₀, NH₃, CO, and NO_x, respectively. The emission reduction percentage of each pollutant in 2019 under the control policies relative to the baseline scenario ranged from 15.6% to 82.4%.

[Chemical Components and Sources of PM2.5 and Their Evolutive Characteristics in Zhengzhou]

To explore the main sources of PM_2.5 and the characteristics of seasonal differences in Zhengzhou, PM_2.5 sampling was conducted in 2019 and the concentrations of inorganic water-soluble ions, carbon components, and various elements were analyzed. Results showed that the average mass concentration of PM_2.5 in 2019 was (67.0±37.2) μg ·m^-3 with the highest concentration in winter and the lowest in summer. The main components of PM_2.5 were nitrate, ammonium, sulfate, organic matter, crustal matter, and elemental carbon. In spring and autumn, PM_2.5 was greatly affected by crustal matter and elemental carbon, and In summer, concentrations were mainly affected by sulfate. In winter, the concentrations of organic matter and nitrate increased significantly, produced by photochemical reactions in summer and aqueous-phase reactions under high humidity in winter. Carbonaceous aerosols were greatly influenced by automobile exhaust emission, coal combustion, and biomass combustion. Source apportionment showed that secondary sources were the greatest contributors in all four seasons, particularly in in winter (56.5%). Among the primary sources, the proportion of dust in spring (15.2%) and autumn (11.4%) was slightly higher, and the contribution of motor vehicle pollution was the largest (12.3%) in summer. In winter, PM_2.5was greatly affected by coal combustion (13.2%). From 2014 to 2019, PM_2.5 in Zhengzhou increased annually under the influence of secondary sources. The contribution of industrial sources, biomass combustion sources, and coal combustion sources exhibited a downward trend over this period.

[Effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy for screening imported patients with COVID-19 in Xiamen]

Objective: To analysis effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy (combined screening strategy) for screenin the imported patients with COVID-19 in Xiamen. Methods: The study populations were overseas travelers arriving in Xiamen from March 17 to December 31, 2020, and overseas travelers who had quarantine outside Xiamen for less than 21 days from July 18 to December 31, 2020. Data were collected and analyzed on the timing of detection, pathways, and test results of the imported patients with COVID-19 after implementing combined screening strategy. Results: A total of 304 imported patients with COVID-19 were found from 174 628 overseas travelers and 943 overseas travelers from other cities. A total of 163 cases (53.6%) were diagnosed by multitime, multisite intensive nucleic acid testing after positive finding in total antibody testing. Among them, 27 (8.9%) were first positive for nucleic acid in 14 plus 7 day quarantine and 136 were first positive for nucleic acid in 14-day quarantine. Only 8 of these individuals were tested positive for nucleic acid after positive total antibody testing. The other 128 individuals were tested positive for nucleic acid after being negative for average 2.3 times (maximum of 6 times). Aditional 155 cases might be detected by using the combined "14 plus 7 day quarantine" and " nucleic acid plus total antibody testing" strategy compared with "14-day quarantine and nucleic acid testing" strategy, accounting for 51.0% of the total inbound infections. So the combined screening strategy doubled the detection rate for imported patients with COVID-19. No second-generation case caused by overseas travelers had been reported in Xiamen as of February 26, 2021. Conclusions: Xiamen's combined screening strategy can effectively screen the imported patients with COVID-19 who were first positive for nucleic acid after 14 day quarantine. Compared with "14 day quarantine and nucleic acid testing", the combined screening strategy improved detection rate and further reduced the risk of the secondary transmission caused by the imported patients with COVID-19.

An ultra-sensitive gas sensor based on a two-dimensional manganese porphyrin monolayer

The development of highly sensitive, low-power consuming, stable and recyclable gas sensing devices at room temperature has become an important solution for environmental safety detection. Utilizing a two-dimensional metalloporphyrin monolayer for gas sensing is appealing due to its large specific surface area and high surface activity. A two-dimensional manganese porphyrin monolayer (2DMnPr) is selected from 2D metalloporphyrins with 3d metal centers due to its semi-metallicity to explore its gas sensing properties. Using first-principles calculations, we systematically investigate the electronic structures and adsorption characteristics of gas molecules with toxicity and greenhouse effect on the surface of 2DMnPr, including H2S, CO, CO2, SO2, NO and NO2. The strength of the interaction and charge transfer between the 2DMnPr surface and the adsorbed molecules have a direct effect on the electronic properties and the sensing properties of the adsorbent surface. The sensing performance of the 2DMnPr adsorbent is evaluated via two observable parameters: work function and electrical conductivity. The work functions of 2DMnPr after the adsorption of CO, SO2, NO and NO2 gas molecules increase by different degrees depending on the charge transfer, and those of the H2S and CO2 cases decrease. In our simulation, adsorption of CO, SO2, NO and NO2 gas molecules affects the electronic properties of 2DMnPr markedly, and current-voltage characteristics within a low bias range uncover the superior sensitivity of the conductivity of the 2DMnPr monolayer to these molecules. Besides, the sensing performance is demonstrated to be stable under strain and at room temperature. The desorption time of a gas is positively related to its adsorption energy. The recovery time of CO is predicted to be short enough to realize sustainable detection at room temperature, and the SO2, NO and NO2 gases can also be desorbed at higher temperatures. These results demonstrate that 2DMnPr enables the sensitive detection of these gases and predict the potential application of 2DMnPr as an ultra-sensitive, low-power, stable and recyclable gas sensor at room temperature.

[Spatiotemporal Variations in Fine Particulate Matter and the Impact of Air Quality Control in Zhengzhou]

To study the spatiotemporal variations in fine particulate matter (PM_2.5) and the impact of air quality management in autumn and winter in Zhengzhou, five sites were selected to collect PM_2.5 samples from the autumn of 2017 to the winter of 2018, and the characteristics of the chemical components were analyzed. The positive matrix factorization (PMF) model was also applied to identify the sources of PM_2.5, and the effect of air quality control was evaluated to provide support for air quality control in autumn and winter in the next stage. The PM_2.5 concentrations in the four seasons in Zhengzhou were ranked as winter > autumn > spring > summer. The PM_2.5 concentration at Zhengzhou University (ZZU) was the highest (8.7% higher than the average concentration), and the PM_2.5 concentrations at the other sites were slightly lower than the average concentration. The concentration of water-soluble ions (WSIs) was low in spring and summer and high in autumn and winter. The average proportions of SO₄^2-, NO₃^-, and NH₄⁺ in the nine WSIs were as high as 22.5%, 43.6%, and 23.4%, respectively. The proportion of Cl^- in winter was higher than that in the other seasons owing to coal combustion (6.7% and 6.6% in 2017 and 2018, respectively). Owing to wind and sand, the proportions of Ca²⁺ and Mg²⁺ in spring were the highest (4.4% and 0.4%, respectively), and those at the Jiancezhan (JCZ) and ZZU sites were higher than those at the other sites. K⁺, as a marker of biomass burning, had a higher proportion in spring, autumn, and winter. The proportion of K⁺ in the spring of 2018 was 1.9%, those in the autumn and winter of 2017 were 1.6% and 2.1%, respectively, and those in the autumn and winter of 2018 were 1.3% and 1.8%, respectively. JCZ, Hangkonggang (HKG), and Xinmi (XM) had higher proportions of NO₃^-, and the proportions of SO₄^2- were lower. Secondary organic carbon (SOC) pollution was serious in autumn and winter, and the concentration accounted for more than half of the organic carbon (OC). In 2018, the SOC/OC at the JCZ and ZZU sites decreased compared with that in 2017, but that at the other three sites increased significantly, thereby indicating that different air pollutant emissions in these regions had different performances in response to control policies. The chemical composition reconstruction results showed that the proportion of sulfate was highest in summer (25.0%), the contribution of nitrate was higher in autumn (23.1% and 25.1% for 2017 and 2018, respectively) and winter (20.6% and 23.0% for 2017 and 2018, respectively), the proportion of crustal material was higher in spring (18.2%), and the contribution of secondary organic aerosol (SOA) was the highest in winter (14.1% and 20.5% for 2017 and 2018, respectively). SOA had higher contributions at the JCZ and HKG sites (16.9% and 16.4%, respectively), and ZZU was affected more by primary organic aerosol (14.3%) and crustal materials (12.1%). The PMF results showed that secondary inorganic salts (37.5%), SOA (15.4%), traffic (14.9%), industry (4.8%), coal combustion (16.0%), fugitive dust (6.5%), and biomass burning (2.8%) were the main pollution sources of PM_2.5 in Zhengzhou. SOA and coal combustion contributed more in winter and fugitive dust contributed more in spring, followed by autumn. Biomass burning contributed more in spring and autumn. The urban sites JCZ and ZZU and the characteristic site HKG near the airport were more affected by traffic sources (16.9%, 16.2%, and 16.0%, respectively) than the other sites. The impact of biomass burning on the non-urban sites XM and HKG was slightly larger (both 2.7%), and the contribution of coal combustion to the suburban site XM was higher (16.8%). Owing to the construction around ZZU, the loading of fugitive dust at ZZU was higher than that at other sites. Comparing the results of the two-year autumn and winter, the contribution of SOA, traffic, and industry increased in the autumn and winter of 2018, whereas the contribution of secondary inorganic salts, coal combustion, and biomass burning decreased and the contribution of fugitive dust in winter also decreased. The results showed that the control strategies in autumn and winter had significant effects on the primary sources, including fugitive dust, coal combustion, and industry, and SOA precursor volatile organic compounds should be targeted for further pollution control.

[Health Impact Attributable to the Control of PM2.5 Pollution in China During 2013-2017]

To evaluate the health benefits brought about by air environmental treatment and determine the main drivers of health risk, we calculated the health and economic benefits attributed to PM_2.5 control in Eastern and Central China from 2013 to 2017 by combining PM_2.5 concentrations with a human activity enhanced exposure-response model. The relative contributions of changes in four factors related to the PM_2.5 health burden were also quantified, namely total population, population aging, baseline mortality rates, and ambient exposure. The results show that the population weighted PM_2.5 concentration decreased by 28.73% and the proportion of the population exposed to annual PM_2.5 concentrations lower than or equal to 35 μg·m^-3 increased from 11.23% to 27.91% across the study area during this period. Avoided deaths were decreased to 14.43%, which equates to avoided economic losses of approximately 559 billion RMB. If PM_2.5 concentration meets the Chinese Ambient Air Quality Standard Grade Ⅱ (35 μg·m^-3) or Grade Ⅰ (15 μg·m^-3), or the World Health Organization Air Quality Guidelines (AQG) standards (10 μg·m^-3), a 8.22%, 55.05%, and 79.36% reduction in the total deaths could be achieved in the base year (2017) with equivalent total economic benefits of approximately 319, 2137, and 3081 billion RMB, respectively. Total population, population aging, baseline mortality rates, and PM_2.5 concentrations contributed -2.69%, -12.38%, 1.66%, and 14.57% to PM_2.5-related deaths. Overall, during the study period, the reduction in PM_2.5 concentrations has been the main factor contributing to the reduction in the public health burden. China has implemented significant air pollution control measures; however, the health burden associated with high PM_2.5 concentrations in densely populated areas is still extremely high, requiring an aggressive air pollution control strategy.

[Characteristics, Meteorological Influences, and Transport Source of Ozone Pollution in Zhengzhou City]

Based on online monitoring data of air quality and meteorological parameters, the long-term variations, spatial differences, and meteorological influencing factors of ground-level ozone (O₃) pollution in Zhengzhou were studied. In addition, the transport pathways and potential source regions of O₃ were investigated. The results show that surface O₃ concentrations at the city station in Zhengzhou City increased significantly during the period 2014-2018 (P<0.05) with a growth rate of 15.50 μg·(m³·a)^-1, and the timespan of exceeding pollutant standards was extended. The monthly O₃ variations showed an "M" pattern with the seasonal maximum in summer. The diurnal O₃ variations showed a "single-peak" pattern with a diurnal concentrations peak at 15:00-16:00, while the diurnal peak at the rural station was relatively high (130.94 μg·m^-3). At the urban station, the exceedance probability of O₃ concentrations was relative high when hourly temperature (T) exceeded 23℃, relative humidity (RH) was less than 65%, wind speed (WS) ranged 2.0-4.0 m·s^-1, and wind direction was southeast or northeast. Based on the multivariate linear fitting of impact factors on O₃, the main controlling factors at the city and industrial sites were also identified as T and RH compared to T and WS at the traffic and suburb sites. Back trajectory analysis and potential sources of O₃ during different seasons were significantly different, with the dominant transport trajectories during spring and summer being short-distance and slow-moving airflows from the south and northeast; autumn and winter were characterized by long-distance and quick-moving airflows from the northwest. The high O₃ concentrations observed in summer were mainly affected by local photochemical formation and regional transport from Hebei, Shandong, and Anhui Provinces.

[Characterization, Sources, and Health Risks of PM2.5-bound PAHs During Autumn and Winter in Luoyang City]

In this study, PM_2.5 samples were collected synchronously at Gaoxin and Linxiao in Luoyang City during autumn and winter (4 October 2018 to 30 January 2019). Sixteen priority polycyclic aromatic hydrocarbons (PAHs) associated with fine particulate matter were analyzed by gas chromatography mass spectrometry (GC-MS). The concentrations and composition characteristics of the PAHs on clean and polluted days were studied. Diagnostic ratio analysis and principal component analysis (PCA) were used to identify the emission sources of PM_2.5-bound PAHs and the equivalent carcinogenic concentration of benzo[a]pyrene (BaP) and incremental lifetime cancer risks (ILCRs) model were applied to evaluate health risks. During the sampling period, the concentrations of PAHs at Gaoxin and Linxiao ranged 24.33-90.26 ng·m^-3 and 23.81-76.99 ng·m^-3, respectively. With the increase in PM_2.5 pollution, PAH concentrations increase significantly (the mean PAH concentration on polluted days was approximately 1.3 times higher than during clean days). PAH profiles at different polluting levels were similar; 4-ring PAHs (43%-48%) > 5-6 ring PAHs (32%-35%) > 2-3-ring PAHs (20%-22%). Diagnostic ratios and PCA demonstrated that PAHs in the study area were mainly derived from combustion sources including coal combustion, biomass burning, and motor vehicle emissions. The coal combustion was the main pollution source in the study area (clean days=49.28%-56.38%, polluted days=49.44%-60.60%). The results of the equivalent carcinogenic concentration of benzo[a]pyrene (BaP) and ILCR model revealed that the human health risk on polluted days was higher. Moreover, the cancer risks from adult exposure to PAHs were higher than those child exposure, which has an acceptable level of risk (<10^-6).

[Simultaneous combined radical surgery for hepatic and renal alveolar echinococcosis: an analysis of 10 clinical cases]

Objective: To examine the feasibility, safety and efficacy of simultaneous combined radical surgery for hepatic and renal alveolar echinococcosis (AE). Methods: Clinical dates of consecutive 10 hepatic and renal AE patients who accepted surgical treatment in the First Affiliated Hospital of Xinjiang Medical University during April 2013 to September 2019 were analyzed retrospectively. There were 8 males and 2 females, aged (42.5±10.3) years (range: 27 to 52 years). Seven of them had previously palliative surgical treatment with poor compliance to post-operative medication. All of the patients had hepatic-renal combined AE lesions, and two of them had left lateral and left renal lesions for each, which sized for (726.4±576.1)cm³ (range: 117.0 to 1 998.0 cm³). Extra-hepatic or renal lesions infiltrated to right diaphragm, inferior vena cava, right adrenal gland, abdominal wall, right psoas muscle, duodenum wall and right pulmonary lobe (respectively were 7, 7, 6, 2, 1, 1, 2 cases). Surgery were performed mainly with simultaneous combined surgery and vascular reconstruction techniques for this series. Hemi-hepatectomy or extended right lobectomy was applied in 8 patients, while 2 other patients received ex vivo liver resection and autotransplantation, additionally, one patient had partial hepatectomy for left lateral lobular lesion. Total right nephrectomy, partial right nephrectomy and partial left nephrectomy were respectively performed on 7, 3 and 1 patient(s). Additionally, extra-hepatic or renal lesions were eradicated followed by relevant repairments or reconstructions. Results: Surgeries went well and there was no intra-or post-operative liver or renal dysfunction occurred. During recovery period, 3 cases experienced with hydrothorax and managed well after drainage and supportive treatment, and one patient developed peri-renal urinary leakage and cured by "J" catheter. The subjects were followed-up for 6 to 81 months (median: 21 months), no death, organ dysfunction, chronic or acute kidney diseases occurred. One case encountered with abdominal hernia at post-operative 7^th month and was successfully managed with laparoscopic repair with artificial mesh. No disease recurrence in all patients, which reached clinical cure at last. Conclusion: When complied strictly to indications, simultaneous combined radical surgery could be a feasible, safe and efficient approach for patients with hepatic and renal AE, which is primary or relapsed from previous hepatic AE surgery or interventional therapies as well as neighboring organ AE invasions.

[Characteristics and Sources of PM2.5 Pollution in Typical Cities of the Central Plains Urban Agglomeration in Autumn and Winter]

To study the characteristics of PM_2.5 pollution and the potential sources of its main components in the central plain urban agglomeration in autumn and winter, PM_2.5 samples were collected continually in the four typical cities of Zhengzhou, Luoyang, Anyang, and Xinxiang from October 2018 to January 2019. X-ray fluorescence spectrometry, carbon analysis methods, and ion chromatography were used to determine 18 kinds of inorganic elements, organic carbon (OC)/elemental carbon (EC), and 9 kinds of water-soluble inorganic ions. According to the daily PM_2.5 concentration, three pollution levels were divided, and the comparative analysis for the spatial and temporal variation of PM_2.5 and its main components, i.e., NO₃^-, OC, and 18 kinds of inorganic elements, were studied via the calculation of the nitrogen oxidation rate (NOR), secondary organic carbon (SOC), and enrichment factor. The emission sources and their contribution rates of PM_2.5 pollution level in the four cities were calculated by a chemical mass balance (CMB) model; the potential pollution sources of PM_2.5 and its main components, NO₃^- and OC, in the four cities were analyzed by a backward trajectory model (HYSPLIT) and potential source contribution factor method (PSCF). The results showed that the means of PM_2.5 in Zhengzhou, Luoyang, Anyang, and Xinxiang were (82.1±45.5), (84.7±39.8), (96.8±46.1), and (81.1±36.6) μg·m^-3, respectively, during the sampling period, and the maximum daily mean values were 3.3, 2.6, 3.0, and 2.3 times, respectively, of the Chinese national secondary standard; the main components of PM_2.5 in the four cities were NO₃^- and SOC, and the concentration of NO₃^-, the ratio of NO₃^-/EC, and NOR all increased significantly with the rising of pollution levels, generally showing that the mean values of NO₃^-/EC and NOR of Zhengzhou and Luoyang were a little higher than those of Anyang and Xinxiang; the concentration of SOC, the proportion of SOC in OC, and the ratio of SOC/EC all increased with the rising of pollution levels. From the concentration and enrichment degree of inorganic elements, As was the highest in Zhengzhou; Mn and Fe were the highest in Luoyang; Zn, Ni, and Cr were the highest in Anyang; and Cu and Pb were the highest in Xinxiang. Secondary nitrate, secondary sulfate, organic matter, coal combustion, motor vehicle, dust, biomass burning, and industrial processes were the main PM_2.5 pollution sources in the four cities, with the highest contribution rate of secondary nitrate in Zhengzhou (37.7%), the highest contribution rate of vehicle sources in Xinxiang (14.1%), and a relatively high contribution rate of industrial process source in Luoyang (7.0%) and Anyang (6.8%). The northwest direction of airflow contributed 51.6%, 49.2%, 49.6%, and 46.3% of the total airflow in Zhengzhou, Luoyang, Anyang, and Xinxiang, respectively. From the potential pollution area of each city, the Zhengzhou area was mainly concentrated in Henan province, the Luoyang area was mainly concentrated in the south of Henan province and Fen-wei plain, and the Anyang and Xinxiang areas were mainly concentrated in Henan province and the Beijing-Tianjin-Hebei transport belt. The pollution levels of OC in Anyang and Xinxiang were also affected by the northwest Anhui, southwest Shandong, southeast Shanxi, and north Shaanxi.

[Exhaustion of CD8+ T cell immune functions in spleen of mice with different doses of Echinococcus multilocularis infections]

OBJECTIVE

To examine the changes in the immune functions of CD8⁺ T cells in the spleen of mice following Echinococcus multilocularis infections at various doses and at different time points.

METHODS

The E. multilocularis protoscoleces were collected, and E. multilocularis infection was modeled in mice via the hepatic portal vein at doses of 50 (low-dose), 500 (medium-dose) and 2 000 protoscoleces (high-dose), while physiological saline served as controls. Mouse spleen was isolated 2 (earlystage), 12 (middle-stage) and 24 weeks post-infection (late-stage), and spleen lymphocytes were harvested. The phenotype of memory CD8⁺ T cells and 2B4 expression were quantified in the mouse spleen, and the secretion of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-17A and IL-10 was measured.

RESULTS

A central-memory phenotype was predominant in the CD8⁺ T cells in the spleen of mice at the early stage of high-dose protoscolece infections, and the proportion of central-memory CD8⁺ T cells was significantly greater in the high-dose group than in the control group (35.50% ± 2.00% vs. 25.90% ± 2.46%, P < 0.01), while a effector- memory phenotype was predominant in the CD8⁺ T cells in the spleen of mice at the late stage of medium- and high-dose protoscolece infections, and the proportions of effector-memory CD8⁺ T cells were significantly greater in the medium- (25.70% ± 4.12%) and high-dose group (28.40% ± 4.12%) than in the control group (10.50% ± 6.45%) (P < 0.05). The proportions of the central-memory CD8⁺ T cells were significantly higher in the high-dose group than at middle and late stages than at the early stage (P < 0.01), and the proportion of effector-memory CD8⁺ T cells was significantly greater in the high-dose group at the late stage than at early and middle stages (P < 0.05). The secretion of IFN-γ and IL-17A by spleen CD8⁺ T cells was elevated in the low- and medium-dose groups at the early stage of infection, and high-dose protoscolece infection promoted the secretion of IFN-γ and TNF-α by spleen CD8⁺ T cells; however, the levels of IFN-γ and TNF-α were significantly lower at the late stage than at the early and middle stages (P < 0.05). In addition, high 2B4 expression was detected in spleen CD8⁺ T cells in the middle- and high-dose groups at the late stage of infection, and the 2B4 expression was significantly higher in the medium(4.73% ± 1.56%) and high-dose groups (4.94% ± 1.90%) than in the low-dose group (2.49% ± 0.58%) and the control group (2.92% ± 0.60%) (P < 0.05).

CONCLUSIONS

E. multilocularis may be killed and eliminated through the host immune responses at the middle and late stages of low- and medium-dose protoscolece infections, while high-dose protoscolece infections may trigger the upregulation of 2B4 expression in mouse spleen CD8⁺ T cells at the late stage, which leads to immune exhaustion and the resultant chronic infections.

Efficient degradation of industrial pollutants with sulfur (IV) mediated by LiCoO2 cathode powders of spent lithium ion batteries: A "treating waste with waste" strategy

Strategies to maximize the reuse of electronic and industrial wastes have scientific, economic, social and environmental implications. We herein propose a strategy of "treating waste with waste" using LiCoO₂ cathode powders from spent lithium ion batteries to eliminate industrial pollutants led by sulfur (S) (IV) in waste water. By radical scavenging experiments and electron spin resonance (ESR) analysis, we identified singlet ¹O₂ as the dominant species while SO₄^- and OH as the secondary species for decontamination during the oxidization process mediated by LiCoO₂ powders. The intrinsic mechanism of S(IV) conversion was revealed to be two-step hydrogen migrations from HSO₃^- to O₂ occurring on LiCoO₂ surface by density functional theory (DFT) calculations. The surface of LiCoO₂ powders plays a key role in anchoring sulfur species and forming surface complex as an excellent medium, which is found to be stable and reusable by material characterizations and the recycling experiment. Free Co(II) ions in solvents have no catalysis effect on the conversion of pollutants. Our work offers a particularly vivid example for rational reuse of electronic wastes to eliminate industrial pollutants, and may raise economic benefits in environmental practice due to two aims achieved in once action.

[Seasonal Chemical Composition Characteristics and Source Apportionment of PM2.5 in Zhengzhou]

The aim of this study was to fully understand the pollution characteristics and sources of PM_2.5 in Zhengzhou, and to investigate the differences in four seasons and between urban and suburban areas. At the Zhengzhou environmental monitoring center (urban areas) and Zhengzhou University (suburban areas), 1284 environmental PM_2.5 samples were collected in the four seasons of 2018. The concentrations of nine kinds of inorganic water-soluble ions, organic carbon, elemental carbon and 27 kinds of elements, were measured by ion chromatography, carbon analyzer, and X-ray fluorescence spectrometry, respectively. Enrichment factors (EF), index of geoaccumulation (I_geo), potential ecological risk index (RI), chemical mass balance model (CMB), backward trajectory, and potential source contribution function were the methods used to study the chemical component characteristics and source differences of PM_2.5 in different seasons in the urban and suburban areas of Zhengzhou. The results showed that the annual average PM_2.5 concentration at the Zhengzhou environmental monitoring center and Zhengzhou University sites reached (59.7±24.0) μg·m^-3 and (74.7±13.5) μg·m^-3, respectively. The PM_2.5 concentration at the suburban point was higher than at the urban point with the exception of winter, and the seasonal mean concentration decreased in the order of winter > autumn > spring > summer. Compared with the urban areas, the suburban areas were more affected by crustal substances in spring, and the concentrations of all components were higher in summer and autumn than the urban areas. Nevertheless, urban areas were more affected by coal burning sources and motor vehicle sources in winter. The component analysis results showed that the influences of soil dust and building dust were greater in the suburbs in spring than in the urban areas. In autumn, the suburbs were more affected by biomass sources than the urban areas, while the urban areas were more affected by building dust than were the suburbs. The concentrations of Cu, As, Zn, Pb, and Sb were strongly influenced by anthropogenic sources, and the enrichments of Zn, Cu, As, and Pb in urban areas were greater than in the suburbs. In addition, Zn, Cu, As, and Pb exhibited potential ecological risks. The outcomes of the CMB model showed that dust sources, secondary sulfate, secondary nitrate, and coal burning sources contributed significantly to PM_2.5 concentrations in spring, summer, autumn and winter, respectively. The contributions of secondary pollution sources (secondary organic aerosol, secondary sulfate, and secondary nitrate) and motor vehicle sources to urban areas were higher than to suburban areas, and the influences of biomass sources in autumn and winter were significantly higher than in spring and summer and urban areas. The backward trajectory results indicated that the local PM_2.5 concentration was affected by distant transmission from the northwest except in summer, was affected by neighboring provinces in the east in four seasons, and was affected by transmission from the south, with the exception of winter. Furthermore, the consequences of potential sources demonstrated that the local PM_2.5 concentration was mainly affected by the potential areas in Henan province and its boundary with neighboring provinces.

[Evolution and Evaluation of O3 and VOCs in Zhengzhou During the National Traditional Games of Ethnic Minorities Period]

During the National Traditional Games of Ethnic Minorities (NTGEM) 2019, air quality in Zhengzhou was analyzed to evaluate the impact of pollution prevention and control measures on Zhengzhou. Ground-observed meteorological and pollutant data as well as the chemical compositions of volatile organic compounds (VOCs) were investigated. The results showed that the six parameters of pollutants in the safeguard period in 2019 indicated a downward trend as compared with that during the same time in 2018, and the average concentrations of PM_2.5 and PM₁₀ were decreased by 16.2% and 25.1%, respectively. However, the average concentration of O₃ was only reduced by 3.7%. The daily proportions of primary pollutants of O₃ increased to 90% during the NTGEM, and the ozone pollution was severe in this period. Meanwhile, the concentration of total volatile organic compounds (TVOCs) in the safeguard period was 26.21×10^-9, which was significantly lower than that during the historical period. Six emission sources of the VOCs were identified using PMF model, including vehicle exhaust (28%), LPG evaporation (21%), combustion source (16%), industrial emissions (15%), solvent utilization (15%), and biogenic VOCs (5%). During the NTGEM period, the control of combustion sources and industrial sources was evident.

[Emission Inventory of VOCs Components in Zhengzhou and Their Ozone Formation Potential]

In this study, according to the activity levels of volatile organic compounds (VOCs) sources and source profiles, a 2016-based inventory of the speciation emission of the VOCs was established and the ozone formation potential (OFP) were estimated in Zhengzhou. The results showed that the total VOCs emission in Zhengzhou in 2016 was 96215.3 t. The highest emission source was on-road mobile source (29.7%) followed by solvent use sources (28.1%). The species that contributed the highest emission was alkanes (29.8%) followed by aromatics (29.0%). The OFP in Zhengzhou in 2016 was 341291.0 t with the highest contributing source as on-road mobile (30.5%) followed by solvent use source (28.8%). Moreover, the light duty gasoline vehicle, use of interior wall coatings, vehicle surface coating, gas station loading and unloading, and manufacture of non-metallic mineral were the major secondary emission sources of OFP, which needed to be controlled for reducing ozone pollution in Zhengzhou. For VOCs species group, the higher contribution groups were aromatics (42.8%) and alkenes (38.9%). The sources that produced m/p-xylene, propylene, ethylene, and other species should be paid more attention.

[Characteristics and Source Apportionment of VOCs at Different Pollution Levels During the Winter in an Urban Area in Zhengzhou]

In this study, volatile organic compound (VOC) species were measured at an urban site in Zhengzhou from January 3 to 23, 2019, to investigate the composition, variation characteristics, sources, and effects on secondary organic aerosol (SOA) formation of VOCs at different pollution levels. Results showed that oxygenated VOCs and alkanes were the main components of VOCs, while ethyl acetate and acetone were the most abundant species. During the process from clean days to heavy pollution days, the mixing ratio of VOCs approximately doubled, and the mixing ratios of most species continued to increase as the pollution level increased. Based on the positive matrix factorization (PMF) model, during the observation period, VOCs mainly originated from vehicle emissions, industrial emissions, combustion sources, solvent utilization, and liquefied petroleum gas (LPG) utilization. There were significant differences in the source contribution at different pollution levels, and the contributions of industrial emissions and solvent utilization during the heavy pollution days increased to 9 times and 3 times that of the clean days, respectively. With respect to the SOA formation potential (SOA_p), aromatics were the component that contributed the most, and toluene and m/p-xylene were the species that contributed the most, while solvent utilization was the greatest source contributor. During the heavy pollution period, the total SOA_p increased to approximately 2.6 times that of clean days. There is a great need to reduce winter haze pollution in Zhengzhou by strengthening the control of aromatic emissions and related sources such as solvent utilization.

[Evaluation of the Reduction in PM2.5 Concentration During the National Traditional Games of Ethnic Minorities in Zhengzhou]

To evaluate the effect of the implementation of emission reduction measures and the improvement in air quality during the National Traditional Games of Ethnic Minorities in Zhengzhou, a series of online instruments were used to continuously observe air pollutants and components of PM_2.5 from August 5 to September 30, 2019. Three cases, including before emission reduction (August 5-24), during emission reduction (August 25 to September 18), and after emission reduction (September 19-30), were classified by the implementation of control measures. The results show that the growing concentration of PM_2.5 after the cancellation of emission abatement measures (11.7 μg·m^-3) was greater than that during the emission reduction (2.3 μg·m^-3) compared to the PM_2.5 concentration before emission reduction. This thus indicates that the control measures have a significant effect on reducing particulate matter. The main components of PM_2.5 were organic matter, nitrate, ammonium, sulfate, and crustal elements. Compared to the proportion of components in PM_2.5 before and during the control periods, organic matter and nitrate increased by 3.9% and 0.9%, respectively, while sulfate, ammonium, and crustal elements decreased by 1.1%, 1.9%, and 2.2%, respectively. The results of source appointment by positive matrix factorization show that secondary sulfate, secondary nitrate, secondary organic aerosols, vehicular emissions, industrial emissions, dust, and coal combustion are the main sources of PM_2.5. Emission abatement measures reduced the contributions of primary sources such as dust, coal combustion, and industry by 8.3%, 8.2%, and 8.1%, respectively. In contrast, the contributions of secondary organic and nitrate aerosols increased during the control periods, which suggested that the control measures implemented in Zhengzhou had a weaker emission reduction effect on nitrogen oxide and volatile organic compounds than on primary sources of PM_2.5.

[Ambient VOCs Characteristics, Ozone Formation Potential, and Source Apportionment of Air Pollution in Spring in Zhengzhou]

Ambient volatile organic compounds (VOCs) were determined by GC 5000 online gas chromatography in the urban site of Zhengzhou from April 15 to May 15, 2018. Based on chemical composition analysis, in this study, the concentrations, ozone formation potential (OFP), and source apportionment were studied. The results show that the averaged volume fraction of VOCs in Zhengzhou during spring was 40.26×10^-9, which was 23% higher on polluted days (44.12×10^-9) than on non-polluted days (35.82×10^-9). The contribution of VOC species to OFP was in the order: alkenes > aromatics > alkanes > alkyne. The five factors identified by the PMF model were liquefied petroleum gas (LPG) volatilization sources (66.05%), motor vehicle exhaust sources (47.39%), industrial solvent sources (37.51%), fuel combustion sources (37.80%), and biogenic sources (11.25%). The contributions of LPG volatilization sources and biogenic sources on polluted days were higher by 22.92% and 68.50% than on non-polluted days, respectively.

Charge Transfer Boosting Moisture Resistance of Seminude Perovskite Nanocrystals via Hierarchical Alumina Modulation

Boosting the stability improvement of cesium lead halide (CsPbX₃) perovskite nanocrystals (NCs) remains a serious challenge. In this work, CsPbX₃ NCs are effectively anchored on a hierarchical (h-) alumina (Al₂O₃) substrate to form seminude CsPbX₃@h-Al₂O₃ composites, which can emit strong green light even after being stored in water for 30 days, in sharp contrast to the pure CsPbBr₃ NCs. Other oxides, such as TiO₂, ZnO, and SiO₂, have no boosting effect on the moisture resistance of perovskite NCs. Subsequent density functional theory calculations reveal a significant charge transfer and strong Coulomb attraction between CsPbBr₃ and Al₂O₃. The substantial charge transfer via alumina substrate modulation not only can enhance the internal stability of CsPbBr₃ but also can cause CsPbBr₃ to be insensitive to water adsorption. These findings are expected to deepen our understanding of improving the stability of CsPbBr₃ NCs and shed light on the design of novel perovskite composites for long-term stable optoelectronic devices.

Effect of Different Doses of Intrathecal Dexmedetomidine as an Adjuvant Combined With Hyperbaric Ropivacaine in Patients Undergoing Cesarean Section

Objective

In this study, we aim to investigate the effect of different doses of dexmedetomidine as an adjuvant to hyperbaric ropivacaine in spinal anesthesia for cesarean section.

Methods

Seventy-five parturients with American Society of Anesthesiologists (ASA) I or II were anesthetized with intrathecal ropivacaine (12.5 mg) alone (R group) or in combination with dexmedetomidine 3 μg (RD3 group) and 5 μg (RD5 group) to undergo a cesarean section. The anesthetic parameters, postoperative analgesia, stress responses and neonates outcomes were monitored.

Results

The onset time of sensory block to T10, T4, and peak level in the RD3 group and RD5 group were significantly shorter than those in the R group (p < 0.05). The time of the level of sensory block to descend two segments and to T10 in the RD3 group(57.28 ± 16.65 min, 3.87 ± 1.60 h) and RD5 group (71.92 ± 10.10 min, 3.99 ± 1.06 h) were longer than that in the R group (40.64 ± 12.06 min, 1.98 ± 1.01 h) (p < 0.05). The median time of motor blockade to both legs score 3 on the Bromage scale (B3B3) in the RD3 group and RD5 group was shorter than that in the R group (p < 0.001). The time of motor blockade recovery to both legs score 0 on the Bromage scale (B0B0) in the RD5 group (3.6 h) was longer than that in the R group (2 h) or RD3 group (2.2 h) (p < 0.001). Visceral traction response and abdominal muscle relaxation during the operation in the RD3 group and the RD5 group were better than that in the R group. The Visual Analogue Score (VAS) in the 12 h after the operation in the RD3 group (3.30 ± 1.17) and RD5 group (2.80 ± 0.87) was smaller than that in the R group (3.80 ± 1.47) (p < 0.05). The incidence of shivering in the RD3 group and RD5 group was significantly lower than that in the R group (p < 0.05). The postoperative concentrations of c-reactive protein (CRP), interleukin-6 (IL-6) and cortisol in the RD3 and RD5 groups were lower than that in the R group (p < 0.05).

Conclusion

3 µg intrathecal dexmedetomidine as an adjuvant to ropivacaine improved intraoperative somato-visceral sensory block characteristics and postoperative analgesia, alleviated shivering in parturients, and did not prolong the time of motor block or produce any side effects, which makes this dose appropriate for cesarean delivery.

Cinical Trial Registration

ChiCTR, identifier ChiCTR1800014454. Registered 15 January 2018, http://www.chictr.org.cn/edit.aspx?pid=24613&htm=4