Temporal-spatial characteristics and sources of heavy metals in bulk deposition across China

With the rapid development of industries, agriculture, and urbanization (including transportation and population growth), there has been a significant alteration in the emission and atmospheric deposition of heavy metal pollutants. This has consequently given rise to a range of ecological and environmental health issues. In this study, we conducted a comprehensive two-year investigation on the temporal and spatial distribution characteristics of heavy metals in atmospheric deposition across China based on the Nationwide Nitrogen Deposition Monitoring Network (NNDMN). The atmospheric bulk deposition of Lead (Pb), Arsenic (As), Nickel (Ni), Selenium (Se), Chromium (Cr) and Cadmium (Cd) were 6.32 ± 1.59, 4.49 ± 0.57, 1.31 ± 0.21, 1.05 ± 0.16, 0.60 ± 0.06 and 0.21 ± 0.03 mg m-2 yr-1, respectively, with a large variation among the different regions of China. The order for atmospheric deposition flux was Southwest China > Southeast China > North China > Northeast China > Qinghai-Tibet Plateau and rural area > urban area > background area. The concentrations of heavy metals in bulk deposition exhibit seasonal variation with higher levels observed during winter compared to summer and spring, which are closely associated with anthropogenic activities. The Positive Matrix Factorization (PMF) results indicated that combustion, industrial emissions and traffic are the primary contributors to atmospheric deposition of heavy metals. The single factor pollution index (Pi) of heavy metals is consistently below 1, and the composite pollution index (Ni) is 0.16 across China, indicating that atmospheric heavy metal deposition is at a pollution-free level. The comprehensive potential ecological risk index of heavy metals is 11.8, with Cd exhibiting the highest single factor potential ecological risk index at 7.09, suggesting that more attention should be paid to Cd deposition in China. The present study reveals the spatial-temporal distribution pattern of atmospheric heavy metals deposition in China, identifying regional source characteristics and providing a theoretical foundation and strategies for reducing emissions of atmospheric pollutants.

Effects of intercropping on soil greenhouse gas emissions - A global meta-analysis

Diversified cropping systems, such as intercropping, have shown multifunctionality in agronomic productivity promotion, pest control, and soil health improvement. However, the intense interaction between crop species stimulates soil carbon and nitrogen turnover, and intercropping systems cause inexplicit effects on soil greenhouse gas emissions (GHG). Therefore, a comprehensive meta-analysis using 52 published articles (531 paired observations) was conducted to elucidate the effects of intercropping on soil N2O, CO2, and CH4 emissions under different environmental conditions and field practices to identify the primary driving factors, such as climate, soil and field practices. The results showed that intercropping treatment had a non-significant impact on the three GHG emissions on average. However, using a cereal-legume intercropping regime, adopting moderate N application rate or intercropping in alkaline soils could significantly mitigate soil N2O emission. Additionally, intercropping in soils with high soil organic carbon reduce soil CH4 emission. On the contrary, increasing intercropping duration, or adopted in soils with moderate soil total N tended to stimulate CO2 emission. The mixed-effect model selection indicated that initial soil pH, MAP, MAT, tillage regime, and intercropping duration and type were significant moderators in regulating soil GHG emissions. Our findings explicitly elucidated soil GHG responses to intercropping practice. Further studies are warranted on the evaluation of long-term intercropping effects to improve the comprehensive understanding of C and N balance and global warming potential under intercropping.

Suitable biochar application practices simultaneously alleviate N2O and NH3 emissions from arable soils: A meta-analysis study

Nitrogen (N) fertilization profoundly improves crop agronomic yield but triggers reactive N (Nr) loss into the environment. Nitrous (N2O) and ammonia (NH3) emissions are the main Nr species that affect climate change and eco-environmental health. Biochar is considered a promising soil amendment, and its efficacy on individual Nr gas emission reduction has been widely reported. However, the interactions and trade-offs between these two Nr species after biochar addition have not been comprehensively analysed. The influencing factors, such as biochar characteristics, environmental conditions, and management measures, remain uncertain. Therefore, 35 publications (145 paired observations) were selected for a meta-analysis to explore the simultaneous mitigation potential of biochar on N2O and NH3 emissions after its application on arable soil. The results showed that biochar application significantly reduced N2O emission by 7.09% while having no significant effect on NH3 volatilisation. Using biochar with a low pH, moderate BET, or pyrolyzed under moderate temperatures could jointly mitigate N2O and NH3 emissions. Additionally, applying biochar to soils with moderate soil organic carbon, high soil total nitrogen, or low cation exchange capacity showed similar responses. The machine-learning model suggested that biochar pH is a dominating moderator of its efficacy in mitigating N2O and NH3 emissions simultaneously. The findings of this study have major implications for biochar application management and aid the further realisation of the multifunctionality of biochar application in agriculture, which could boost agronomic production while lowering environmental costs.

Impact of COVID-19 infection experience on mental health status of intensive care unit patients' family members: a real-world study

PURPOSE

Family members of patients hospitalized in intensive care unit (ICU) are susceptible to adverse psychological outcomes. However, there is a paucity of studies specifically examining the mental health symptoms in ICU patients' family members with a prior history of coronavirus disease 2019 (COVID-19) infection.

AIM

This study aimed to investigate mental health status and its influencing factors of ICU patients' family members with previous COVID-19 infection experience in China.

DESIGN

Nationwide, cross-sectional cohort of consecutive participants of family members of ICU patients from 10 provinces randomly selected in mainland China conducted between October 2022 and May 2023.

METHODS

The basic information scale, Self-rating depression scale, Self-rating Anxiety Scale, Impact of Event Scale-Revised, Pittsburgh sleep quality index, Perceived Stress Scale, Connor-Davidson resilience scale, Simplified Coping Style Questionnaire were employed to explore mental health status among participants.

RESULTS

A total of 463 participants, comprising 156 individuals in Covid-19 family member cohort (infection group) and 307 individuals in control family member cohort (control group), met inclusion criteria. The infection group exhibited significantly higher incidence of composite mental health symptoms compared to control group (P = 0.017). Multivariable logistic regression analysis revealed that being female, engaging in physical/mental labor, residing in rural areas, and having children were identified as risk factors for the development of depression, anxiety, and post-traumatic stress disorder symptoms, while medical history of surgery was protective factor. A predictive model demonstrated a favorable discriminative ability and excellent calibration.

CONCLUSION

COVID-19 infection experience regarded as new traumatic stressors worsen mental health status of ICU patients' family members.

Crop-specific ammonia volatilization rates and key influencing factors in the upland of China - A data synthesis

Ammonia (NH₃) is an important alkaline reactive nitrogen (Nr) species which is involved in global nitrogen (N) biogeochemical cycling, but which has negative impacts on the environment and human health. In order to better understand and control the NH₃ loss potential in soil-upland crop systems in China, an integrated data analysis including 1302 observations from 236 published articles between 1980 and 2021 was conducted. The typical NH₃ volatilization rate (AVR) and the main factors influencing AVR in the major Chinese upland crops (maize, wheat, openfield vegetables and greenhouse vegetables and others) were estimated and analyzed. The mean AVR for maize, wheat, openfield vegetables and greenhouse vegetables were 7.8%, 5.3%, 8.4% and 1.8%. The most important influencing factors were fertilizer placement, meteorological conditions (especially temperature and rainfall) and soil properties (especially SOM). Subsurface N application produced a significantly lower AVR compared to surface application. High N recovery efficiency and N agronomic efficiency were generally associated with low AVRs. In conclusion, high N application rates, inefficient application methods and the use of loss-prone N fertilizer types are the main factors responsible for high AVRs in major Chinese croplands.

The application of machine learning to air pollution research: A bibliometric analysis

Machine learning (ML) is an advanced computer algorithm that simulates the human learning process to solve problems. With an explosion of monitoring data and the increasing demand for fast and accurate prediction, ML models have been rapidly developed and applied in air pollution research. In order to explore the status of ML applications in air pollution research, a bibliometric analysis was made based on 2962 articles published from 1990 to 2021. The number of publications increased sharply after 2017, comprising approximately 75% of the total. Institutions in China and United States contributed half of all publications with most research being conducted by individual groups rather than global collaborations. Cluster analysis revealed four main research topics for the application of ML: chemical characterization of pollutants, short-term forecasting, detection improvement and optimizing emission control. The rapid development of ML algorithms has increased the capability to explore the chemical characteristics of multiple pollutants, analyze chemical reactions and their driving factors, and simulate scenarios. Combined with multi-field data, ML models are a powerful tool for analyzing atmospheric chemical processes and evaluating the management of air quality and deserve greater attention in future.

Environmental drivers of the leaf nitrogen and phosphorus stoichiometry characteristics of critically endangered Acer catalpifolium

Acer catalpifolium is a perennial deciduous broad-leaved woody plant, listed in the second-class protection program in China mainly distributed on the northwest edge of Chengdu plain. However, extensive anthropogenic disturbances and pollutants emissions (such as SO₂, NH₃ and NO_X) in this area have created a heterogeneous habitat for this species and its impacts have not been systematically studied. In this study, we investigated the leaf nitrogen (N) and phosphorus (P) content of A. catalpifolium in the natural distribution areas, and a series of simulation experiments (e.g., various water and light supply regimes, different acid and N deposition levels, reintroduction management) were conducted to analyze responses of N and P stoichiometric characteristics to environmental changes. The results showed that leaf nitrogen content (LNC) was 14.49 ~ 25.44 mg g^-1, leaf phosphorus content (LPC) was 1.29~3.81 mg g^-1 and the N/P ratio of the leaf (L-N/P) was 4.87~13.93. As per the simulation experiments, LNC of A. catalpifolium is found to be relatively high at strong light conditions (80% of full light), high N deposition (100 and 150 kg N ha^-1), low acidity rainwater, reintroduction to understory area or N fertilizer applications. A high level of LPC was found when applied with 80% of full light and moderate N deposition (100 kg N ha^-1). L-N/P was high under severe shade (8% of full light), severe N deposition (200 kg N ha^-1), and reintroduction to gap and undergrowth habitat; however, low L-N/P was observed at low acidity rainwater or P fertilizer application. The nutrient supply facilitates corresponding elements uptake, shade tends to induce P limitation and soil acidification shows N limitation. Our results provide theoretical guidance for field management and nutrient supply regimes for future protection, population rejuvenation of this species and provide guidelines for conservation and nutrient management strategies for the endangered species.

Reactive N emissions from cropland and their mitigation in the North China Plain

Excessive application of chemical nitrogen (N) fertilizer and inefficient N management are still common in the North China Plain, leading to large reactive N (Nr) losses and pollution, threatening environmental security and public health. Three improved N management practices (33% reduction in N applied (OU), OU combined with partial organic fertilizer substitution (UOM) and the urea in UOM amended with a urease inhibitor (ULOM)) together with no N application (CK) and farmers' conventional practice (CU) were tested on a maize-wheat rotation at Quzhou, Hebei, North China Plain (NCP). Nr emissions were related to WFPS (Water Filled Pore Space), soil mineral N (NH₄⁺-N and NO₃^--N) and soil temperature. Nr emissions and yield-scaled Nr emissions were significantly reduced by partial substitution of organic fertilizer for chemical fertilizer: NH₃ emissions were reduced by 55.8-62.4%. Using a urease inhibitor (Limus®), further reduced NH₃ emissions by 40.2-64.5%. Yield-scaled NH₃ emissions were, on average, reduced by 60.0% and 55.2% in the maize and wheat growing season, respectively, relative to the UOM treatment. Long-term application of organic fertilizer had a significant positive effect on N use efficiency (NUE). Overall, the study shows that appropriated N management such as reducing the N application rate, partial substitution of chemical N by organic N and using a urease inhibitor can reduce Nr emissions and promote NUE in the North China Plain. The methods corresponding to the ULOM and UOM treatments were the most and second most effective, respectively, with high net economic benefits.

Improved soil-crop system management aids in NH3 emission mitigation in China

High ammonia (NH3) emissions from fertilized soil in China have led to various concerns regarding environmental safety and public health. In response to China's blue skies protection campaign, effective NH3 reduction measures need to consider both mitigation efficiency and food security. In this context, we conducted a meta-analysis (including 2980 observations from 447 studies) to select effective measures based on absolute (AV) and yield-scaled (YSAV) NH3 volatilization reduction potential, with the aim of establishing a comprehensive NH3 mitigation framework covering various crop production sectors, and offering a range of potential solutions. The results showed that manipulating crop density, using an intermittent irrigation regime for paddy field rice, applying N as split applications or partially substituting inorganic fertilizer N with organic N sources could achieve reductions in AV and YSAV reduction of 10-20 %; adopting drip irrigation regimes, adding water surface barrier films to paddy fields, or using double inhibitor (urease and nitrification), slow-release or biofertilizers could achieve 20-40 % mitigation; plastic film mulching, applying fertilizer by irrigation or using controlled-release fertilizers could yield 40-60 % reduction; use of a urease inhibitor, fully substituting fertilizer N with organic N, or applying fertilizer by deep placement could decrease AV and YSAV by over 60 %. In addition, use of soil amendments, applying suitable inorganic N sources, or adopting crop rotation, intercropping or a rice-fish production model all had significant benefits to control AV. The adoption of any particular strategy should consider local accessibility and affordability, direct intervention by local/government authorities and demonstration to encourage the uptake of technologies and practices, particularly in NH3 pollution hotspot areas. Together, this could ensure food security and environmental sustainability.

Response of ammonia volatilization to biochar addition: A meta-analysis

There has been increasing interest in and use of biochar as a soil amendment. However, the effects of biochar addition on ammonia volatilization (AV) appeared contradictory from the many reported studies and the main influencing factors remain unclear. Here, we conducted a comprehensive meta-analysis of 41 published articles with 144 observations to reveal the effects of biochar addition on AV and used a boosted regression tree modelling approach to further interpret the contribution of biochar characteristics, soil properties and experimental conditions to this process. On average, biochar addition did not impact on AV, but this varied greatly under different soil, biochar and experimental conditions. The pH of soil and biochar were important factors impacting AV. Biochar application to acidic soil could stimulate AV, and addition of biochar with a high pH and at a low application rate also showed the same trend. In contrast, combining biochar with urea or organic fertilizer, or using wood-based or acidified biochar at appropriate rates had benefits in reducing AV. These findings have major implications for biochar management strategies in agricultural systems, where an important consideration is the mitigation of potentially detrimental environmental consequences.

Efficient androst-1,4-diene-3,17-dione production by co-expressing 3-ketosteroid-Δ1 -dehydrogenase and catalase in Bacillus subtilis

AIMS

3-ketosteroid-Δ¹ -dehydrogenase (KSDD), a flavin adenine dinucleotide (FAD)-dependent enzyme involved in sterol metabolism, specifically catalyses the conversion of androst-4-ene-3,17-dione (AD) to androst-1,4-diene-3,17-dione (ADD). However, the low KSDD activity and the toxic effects of hydrogen peroxide (H₂ O₂ ) generated during the biotransformation of AD to ADD with FAD regeneration hinder its application on AD conversion. The aim of this work was to improve KSDD activity and eliminate the toxic effects of the generated H₂ O₂ to enhance ADD production.

METHODS AND RESULTS

The ksdd gene obtained from Mycobacterium neoaurum JC-12 was codon-optimized to increase its expression level in Bacillus subtilis, and the KSDD activity reached 12·3 U mg^-1 , which was sevenfold of that of codon-unoptimized gene. To improve AD conversion, catalase was co-expressed with KSDD in B. subtilis 168/pMA5-ksdd^opt -katA to eliminate the toxic effects of H₂ O₂ generated during AD conversion. Finally, under optimized bioconversion conditions, fed-batch strategy was carried out and the ADD yield improved to 8·76 g l^-1 .

CONCLUSIONS

This work demonstrates the potential to improve enzyme activity by codon-optimization and eliminate the toxic effects of H₂ O₂ by co-expressing catalase.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study showed the highest ADD productivity ever reported and provides a promising strain for efficient ADD production in the pharmaceutical industry.

High expression of kinesin light chain-2, a novel target of miR-125b, is associated with poor clinical outcome of elderly non-small-cell lung cancer patients

Background:

MiR-125b has critical role in non-small-cell lung cancer (NSCLC) cell migration, and its target genes have not been elucidated. Kinesin-1 light chain (KLC)-2 was predicted as one of miR-125b's targets by bioinformatics analysis. This study is to identify the function of KLC2 and its interaction with miR-125b in NSCLC.

Methods:

Kinesin-1 light chain-2 protein expression and its clinical relevance were analysed in 140 matched NSCLC and adjacent non-neoplastic lung tissues. Both KLC2 gain- and loss-of-function analyses were performed in NSCLC cell lines by transient transfection. The direct interaction between KLC2 and miR-125b was confirmed by a luciferase reporter assay and a transient co-transfection assay as well as an analysis of eight matched clinical samples.

Results:

KLC2 protein was upregulated in NSCLC cell lines and tissues, and was an independent predictor of poor prognosis for elderly NSCLC patients. Kinesin-1 light chain-2 remarkably enhanced the invasive and migratory ability of NSCLC cells. MiR-125b inhibited KLC2 3′-untranslated region luciferase activity and protein expression, and inversely correlated with KLC2 expression in clinical samples. Kinesin-1 light chain-2 almost completely reversed miR-125b-induced inhibition on migration and invasion.

Conclusions:

Kinesin-1 light chain-2 protein overexpression predicts poor survival in elderly NSCLC patients. Kinesin-1 light chain-2 acts as a proto-oncogene and a functional target of miR-125b in NSCLC cells.

Generation and analysis of 10 000 ESTs from the half-smooth tongue sole Cynoglossus semilaevis and identification of microsatellite and SNP markers

Three normalized cDNA libraries were constructed, two of which were constructed from reproductive tissues ovary and testis, and the other one from pooled immune tissues including head kidney, intestine, liver and spleen. A total of 10 542 clones were sequenced generating 10 128 expressed sequence tags (ESTs). Cluster analysis indicated a total of 5808 unique sequences including 1712 contigs and 4096 singletons. A total of 4249 (73%) of the unique ESTs had significant hits to the non-redundant protein database, 2253 of which were annotated using Gene Ontology (GO) terms. A total of 311 microsatellites (with 246 having sufficient flanking sequences for primer design) and 6294 putative SNPs were identified. These genome resources provide the material basis for future microarray development, marker validation and genetic linkage and QTL analysis.

Regulation of Brucella abortus catalase

All aerobic organisms have mechanisms that protect against oxidative compounds. Catalase, peroxidase, superoxide dismutase, glutathione, and thioredoxin are widely distributed in many taxa and constitute elements of a nearly ubiquitous antioxidant metabolic strategy. Interestingly, the regulatory mechanisms that control these elements are rather different depending on the nature of the oxidative stress and the organism. Catalase is well documented to play an important role in protecting cells from oxidative stress. In particular, pathogenic bacteria seem to use this enzyme as a defensive tool against attack by the host. To investigate the significance of catalase in hostile environments, we made catalase deletion mutations in two different B. abortus strains and used two-dimensional gel analysis, survival tests, and adaptation experiments to explore the behavior and role of catalase under several oxidative stress conditions. These studies show that B. abortus strains that do not express catalase activity exhibit increased sensitivity to hydrogen peroxide. We also demonstrate that catalase expression is regulated in this species, and that preexposure to a sublethal concentration of hydrogen peroxide allows B. abortus to adapt so as to survive subsequent exposure to higher concentrations of hydrogen peroxide.

Induction of CD4(+) T-cell-independent immunoglobulin responses by inactivated influenza virus

Through cognate interaction between antigen-specific B-cell and CD4(+) alphabeta T cells, the CD4(+) alphabeta T cells secrete cytokines that initiate immunoglobulin (Ig) class switching from IgM to IgG. In this study, we show that formalin-inactivated influenza PR8 virus induces virus-specific IgM and IgG responses in the absence of CD4(+) T cells and that all four subclasses of IgG are produced. The immunized CD4-deficient mice were also found to be completely protected against lethal infection with live, pathogenic influenza virus. The ability of CD4(+) T-cell-deficient mice to generate these IgG responses was not found to be impaired when these mice were depleted of CD8(+) T cells with an anti-CD8 monoclonal antibody. In contrast, alphabeta T-cell-deficient mice (TCRbeta(-/-)) were not found to produce significant amounts of IgG upon immunization with formalin-inactivated PR8 virus. These results suggest that CD4(-) CD8(-) double-negative alphabeta T cells are playing a role in regulating Ig class switching in the absence of CD4(+) T cells.

[Re-evaluation of proteinuria and qualitive methods for diagnosis of diabetic nephropathy]

This study was aimed to re-evaluate the proteinuria quantitative and qualitative methods for diagnosis of diabetic nephropathy (DN). 136 cases were divided into two groups of proteinuria negativeness and postiveness by the results of urine routine examination. The clinical and biochemical indices and the frequencies of other diabetic complications of the two groups were compared. The results showed that the blood glucose and glycated Hb in the two groups were increased, especially in the proteinuria negative group (P < 0.01 and 0.05, respectively). There was a high prevalence of hypertension and other diabetic complications in the two groups, and it was higher in the positive group than in the negative group (P < 0.05 and 0.01, respectively). The frequencies of hyperlipoproteinemia in the two groups were over 40%, but no significant defference was observed between them (P > 0.05). There was correlation between hypertension and proteinuria (P < 0.01) but no correlation between diabetic retinopathy and proteinuria. The prevalence of azotemia in the proteinuria negative group was 17.07%. These suggest that the amount of proteinuria can not completely reflect the duration and severity of DN. Negative proteinuria in routine examination cannot rule out DN. For diagnosis of DN, it is necessary to think about all data on blood glucose, blood lipid, blood pressure and the change in fundus oculi.

Enhancement of mucosal immune responses to the influenza virus HA protein by alternative approaches to DNA immunization

DNA immunization provides many advantages as an approach to prevent infectious diseases. However, although previous studies using this approach have demonstrated immune responses in serum, they were not successful in inducing significant levels of antibodies in secretions. In this study, plasmid DNAs expressing the influenza virus hemagglutinin glycoprotein have been evaluated for their ability to induce antibody responses in serum and saliva when used alone or along with either liposomes or bioadhesive polymers as mucosal delivery vehicles. Significant levels of virus-specific Ig in serum as well as secretory IgA in saliva were detected in mice following mucosal DNA immunization. These antibodies were found to block the infectivity of the virus using a plaque reduction assay. Our findings thus indicate that mucosal DNA immunization with specific delivery systems can elicit virus-specific antibody responses in serum as well as IgA responses at mucosal surfaces.

Brucella abortus catalase is a periplasmic protein lacking a standard signal sequence

A periplasmic catalase has been purified and cloned from Brucella abortus. The functional enzyme is a tetramer with a subunit molecular weight of 55,000. All evidence indicates that a typical N-terminal signal sequence is not associated with the export of this protein to the periplasm.

Periplasmic location of Brucella abortus Cu/Zn superoxide dismutase

Two types of superoxide dismutase (SOD) have been found in Brucella abortus, a cytosolic Mn-SOD and a Cu/Zn-SOD of unknown location. We sought to determine the subcellular location of Cu/Zn-SOD in B. abortus ST 19. We report a modified spheroplasting procedure for the release of periplasmic contents from B. abortus cells using a dipolar ionic detergent, Zwittergent 316. This detergent, used in place of EDTA, destabilizes the outer membrane sufficiently to allow penetration of lysozyme and the subsequent selective release of periplasmic proteins by osmotic shock. Cytoplasmic cross-contamination of periplasmic fractions was assessed by assaying for malate dehydrogenase activity. Cyanide-sensitive and cyanide-insensitive SOD activity was measured by both the xanthine oxidase-cytochrome c method and a hematoxylin assay. Results suggest that B. abortus Cu/Zn-SOD activity is periplasmic. This zwittergent-lysozyme extraction procedure may be applicable to the separation, isolation and characterization of many other periplasmic proteins of B. abortus and other Gram-negative organisms especially when cytosolic contamination is undesirable.

[Identification of Chinese drugs by fluorescence spectrum]

Cortex Fraxini, Radix et Rhizoma Rhei, Semen Astragali Complanati, Semen Lini, Bulbus Fritillariae Cirrhosae, Bulbus Fritillariae Thunbergii and their confused medicinal materials have been identified by the fluorescence spectrum. This is a referential method for the identification of Chinese drugs.

[Quantitative determination of strychnine and brucine in semen Strychni and its preparations by gas chromatography]

Contents of strychnine and brucine in dry seeds of Strychnos nux-vomica and its preparations were determined by gas chromatography. The determination conditions were:support Gas Chrom Q; liquid phase 3% OV-101; stainless steel column 0.5 m x 3 mm; column temperature 265 degrees C; FID detector.