MazF-rolling circle amplification combined MALDI-TOF MS for site-specific detection of N6-methyladenosine RNA.

N6-methyladenosine (m6A) is one of the most abundant chemical modifications in RNA and has vital significance in cellular processes and tumor development. However, the accurate analysis of site-specific m6A modification remains a challenge. In this work, a MazF endoribonuclease activated rolling circle amplification (MazF-RCA) combined MALDI-TOF MS assay is developed for the detection of site-specific m6A-RNA. MazF endoribonuclease can specifically cleave the ACA motif, leaving methylated (m6A)CA motif intact. The intact methylated RNA can then be amplified through rolling circle amplification, and the generated reporter oligonucleotides are detected by MALDI-TOF MS. The assay exhibits good quantification ability, presenting a wide linear range (100 fM to 10 nM) with the limit-of-detection lower than 100 fM. Additionally, the assay can accurately detect methylated RNA in the presence of large amount of non-methylated RNA with a relative abundance of methylated RNA down to 0.5%. The developed assay was further applied to detect m6A-RNA spiked in MCF-7 cell RNA extracts, with the recovery rates in the range of 90.64-106.93%. The present assay provides a novel platform for the analysis of site-specific m6A-RNA at high specificity and sensitivity, which can promote the study of RNA methylation in clinical and biomedical research.

Multiplexed discrimination of SARS-CoV-2 variants via duplex-specific nuclease combined MALDI-TOF MS.

The frequent mutations in SARS-CoV-2 significantly increase the virus's pathogenicity and transmissibility while also diminishing the effectiveness of vaccines. Consequently, assays capable of rapidly and simultaneously identifying multiple SARS-CoV-2 variants are essential for large-scale applications that aim to monitor the evolution of the virus. In this work, we propose a method combining duplex-specific nuclease (DSN)-assisted cyclic amplification with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) detection, enabling the simultaneous identification of multiple SARS-CoV-2 variants at high-throughput. Due to the high specificity of DSN, single-base mutations can be resolved by the method. With ultra-sensitive detection by MALDI-TOF MS, a limit of detection of 100 pM viral RNA fragment was demonstrated. The assay was used for simultaneous identification and typing of SARS-CoV-2 Alpha, Beta, and Delta variants. The whole assay can be accomplished within 3 h, and the amplification is performed under constant temperature, making the technique simple in operation and efficient. It is also feasible to extend the technique to the detection of many other variants of the virus. We expect that the method can add value to the rapid screening of viral variants and can play an important role in pandemic control.

Analysis of characteristics and causes of gas explosion accidents: a historical review of coal mine accidents in China.

Objectives This study aimed to provide greater insight into the characteristics of severe and extraordinarily severe gas explosion accidents (SESGEAs). Methods. The study analyzed the accident characteristics and causes of SESGEAs. As an example, we conducted a specialized case analysis using the 24Model (fourth edition) on the recent Baoma coal mine gas explosion. Results. SESGEA data are characterized by greater volatility, with significant differences in the geographical distribution, temporal distribution and attributed characteristics of the accidents. From the accident analysis: chaotic ventilation management was the most serious accident cause of SESGEAs; unsafe acts related to ventilation operations accounted for 18.51% of all unsafe acts; coal miners lack professional safety knowledge and have a serious fluke mentality in mining work; enterprises have insufficient enforcement of safety procedure documents, and lack of attention to the allocation of underground human resources and safety training systems; and the importance of safety, the role of the safety department and satisfaction with safety facilities have become the most serious missing items of safety culture. Conclusion. This study can provide important data support and management basis to assist mine operators in developing more targeted accident prevention strategies.

Comparative study of fault tree analysis and 24Model: taking the cause analysis of the Quanzhou Xinjia Hotel collapse accident as an example.

A comparative study was conducted to compare the accident cause analysis methods of fault tree analysis (FTA) and 24Model. A major accident - the Xinjia Hotel collapse accident - was selected as the research object, the causes of the accident were reanalysed and accident prevention countermeasures were designed based on 24Model and FTA, respectively, and the systematic characteristics of 24Model were summarized. The research shows that both 24Model and FTA can carry out risk assessment, accident cause analysis and preventive countermeasure design based on their own rules. Different from FTA, 24Model has static and dynamic structures of specific forms, the definition of causes and factors in the model is more comprehensive and the analysis method is more hierarchical and normative. 24Model can analyse the deep-level cultural and system causes, but the analysis process does not use quantitative methods, only qualitative methods. 24Model has eight systematic characteristics, such as integrity, hierarchy and dynamics.

Formation and function of multiciliated cells.

In vertebrates, multiciliated cells (MCCs) are terminally differentiated cells that line the airway tracts, brain ventricles, and reproductive ducts. Each MCC contains dozens to hundreds of motile cilia that beat in a synchronized manner to drive fluid flow across epithelia, the dysfunction of which is associated with a group of human diseases referred to as motile ciliopathies, such as primary cilia dyskinesia. Given the dynamic and complex process of multiciliogenesis, the biological events essential for forming multiple motile cilia are comparatively unelucidated. Thanks to advancements in genetic tools, omics technologies, and structural biology, significant progress has been achieved in the past decade in understanding the molecular mechanism underlying the regulation of multiple motile cilia formation. In this review, we discuss recent studies with ex vivo culture MCC and animal models, summarize current knowledge of multiciliogenesis, and particularly highlight recent advances and their implications.

Meta-analysis of risk factors for cardiovascular disease in patients with rheumatoid arthritis.

BACKGROUND: Cardiovascular disease (CVD) is a common complication of rheumatoid arthritis (RA). We aimed to explore the risk factors for cardiovascular disease in patients with rheumatoid arthritis and provide a scientific basis on effective prevention and treatments for CVD in RA patients. METHODS: We searched for a combination of the subject words and free words involved arthritis, rheumatoid, CVD, heart disease, vascular disease, risk factors, etc. from China Knowledge Network, Wanfang, Vip, China Biomedical Literature Database, Pubmed, Embase, Web of Science, Cochrane and other databases for documents published in public in 2000-October 2022.RevMan 5.3 and Stata14.0 analysis software was used to perform a meta-analysis of case-control and cohort studies on risk factors of CVDs in patients with RA published from 2000 to 2022.The Egger method was used to determine whether there was publication bias. RESULTS: Seventeen pieces of literature were included in this meta-analysis. We explored the associations between CVD and different clinical characters such as DAS28 score, rheumatoid factor, triglyceride, age, sex, C-reactive protein, total cholesterol (TC), hypertension, and D dimer. High serum levels of C-reactive protein, TC, and D-dimer, as well as hypertension, are the main risk factors for CVD in patients with RA. The OR and 95% CI of C-reactive protein were 2.06 (1.91-2.23), RR and 95% CI of TC were 1.7 (1.49-1.93), RR and 95% CI of hypertension were 3.58 (2.37-5.40), as well as OR and 95% CI of D dimer were 2.83 (1.48-5.40).Our results performed by the meta-analysis were reliable, with low publication bias existed. CONCLUSION: C-reactive protein, TC, hypertension, and D dimer are the main risk factors for CVD in patients with RA. No protective factors were found.

Effects of target tree management on understory regeneration in Pinus massoniana plantations.

To clarify the effects of target tree management on natural forest regeneration, with Pinus massoniana plantations in the low mountainous regions of eastern Sichuan with target tree densities of 100, 150 and 200 trees·hm-2 as test object, we analyzed the effects of management densities on canopy structure, plant diversity, and soil physicochemical properties on understory regeneration. The results showed that the regeneration index increased with management density, which increased 0.08-0.10 in the managed plantations compared with unmanaged sites. When the density of the target trees was 150 trees·hm-2, an increase of 9 regeneration tree species and an increase of 800 trees·hm-2 in quantity were observed. The dominance of herbaceous species was not prominent, but canopy structure was improved, and the regeneration ability of understory plants was enhanced. The impact of habitat factors on the regeneration index ranked as soil total porosity (0.591) > leaf area index (-0.536) > Shannon index (-0.085) > available P (0.053) > total N (-0.007) > Pielou index (-0.005). Target tree management facilitated understory regeneration in the P. massoniana plantations by improving soil pore conditions, reducing leaf area index, and decreasing herbaceous plant diversity index. A management density of 150 trees·hm-2 was more sui-table for target tree management in P. massoniana plantations.

Soil development following glacier retreat shapes metagenomic and metabolomic functioning associated with asynchronous C and N accumulation.

Glacier retreat caused by global warming may result in the variation of soil organic carbon and nutrient cycling. Yet, the dynamic change of soil microbial functional profiles, especially C metabolism-related, with soil development following glacier retreat are still unclear. In the present study, we investigated the soil microbial communities, metagenomic functioning, and metabolomic profiles along the Hailuogou Glacier forefield representing a 120-year chronosequence. The alpha diversity indices of soil bacteria, protozoa and nifH genes showed an upward trend with increased soil ages, and the beta diversity of soil archaea, bacteria, fungi, protozoa, nifH and nirS genes were significantly correlated with soil ages, in which increasing soil C and P while decreased C/N and pH significantly contributed to the differences of soil microbial communities among the analyzed environmental variables. The metagenomic functional genes related to the metabolisms of Glycogen and Cellulosome, Iron Acquisition and Metabolism were significantly decreased with chronosequence, while the utilization of Xylose and Lactate, Potassium Metabolism, Sulfur Metabolism showing an upward trend with soil ages, in which soil C/N ratios and pH were the most influential factors. In addition, soil C and C/N ratios were also significantly correlated to metabolomic compositions, in which the complexity of the metabolite structure increased with soil ages. Our results indicate that glacier retreat may lead to the asynchronous C and N accumulation along the chronosequence, thereby affecting the metagenomic and metabolomic functioning of soil microbial communities related to C metabolisms during soil development following glacier retreat.

Prevalence of depression and anxiety, and associated factors, among Chinese primary and high school students: A cross-sectional, epidemiological study.

INTRODUCTION: This study aimed to investigate the prevalence of depression and anxiety, and associated factors, among Chinese children and adolescents aged 8-18 years who attend primary or high school. METHODS: A total of 23 005 primary and high school students were recruited from February to December, 2019 for this cross-sectional study. The questionnaire included demographic information, questions assessing suicidality, resilience, depression (Center for Epidemiological Studies Depression Scale for Children), and anxiety (Screen for Child Anxiety Related Disorders). Binary logistic regression was used to analyze the independent correlates of depression and anxiety. RESULTS: Overall, 13.06% of participants experienced depressive symptoms, 22.34% experienced anxiety symptoms, 26.34% experienced transient suicidal ideation, 2.23% had serious suicidal ideation, and 1.46% had a history of suicide attempts. Anxiety (odds ratio [OR], 4.935; 95% confidence interval [CI][4.442-5.485]), suicidality (OR, 2.671; 95% CI[2.203-3.237]), skipping breakfast (OR, 1.920; 95% CI[1.348-2.736]), sleep duration (OR, 0.470; 95% CI[0.398-0.556]) and self-expectations (OR, 1.924; 95% CI[1.550-2.389]) were associated with depression (all p < .05). Depression (OR, 4.424; 95% CI[3.983-4.914]), female sex (OR, 1.903; 95% CI[1.759-2.060]), school-based traumatic experience(s) (OR, 1.905; 95% CI[1.747-2.077]), relationships with teachers (OR, 1.575; 95% CI[1.103-2.249]), and suicidality (OR, 1.467; 95% CI[1.218-1.766]) were associated with anxiety symptoms (all p < .05). DISCUSSION: Depression and anxiety are common among school-age children and adolescents in China. Childhood school- and family-based traumatic experience(s), female sex, and lifestyle factors (eating breakfast, sleep duration, exercising, and Internet use) are significantly associated with mental health among children and adolescents. Developing interventions targeting these factors to protect students from depression and anxiety are needed.

Causes of death in female patients with bladder cancer after local tumor excision and radical cystectomy: a contemporary, US population-based analysis.

Surgery is one of the most important treatments for bladder cancer, including local tumor excision and radical cystectomy. At present, studies on the causes of death for contemporary survivors, especially women, who have received different surgical treatments are limited. Therefore, the study used a population-based cohort study in the United States from 2000 to 2017 to analyze causes of death for women who underwent local tumor excision or radical cystectomy stratified by demographics and tumor stage. standardized mortality ratios (SMRs) were calculated based on general population data. In total, 24,040 female patients who underwent surgical treatments were assessed. Of those 20,780 patients undergoing local tumor excision, 36.6% died of bladder cancer, while 63.4% died of other causes. The risk of death from all causes increased in comparation with the general population (SMR 1.85; 95% CI 1.82-1.87), and the most common non-tumor cause of death was from heart diseases (16.2%; SMR 1.13; 95% CI 1.09-1.16). Among women who receive radical cystectomy, 82.3% of deaths occurred within 5 years after surgery. 66.9% deaths resulted from bladder cancer, and the risk of death from all causes significantly higher than that in the general people (SMR 4.67; 95% CI 4.51-4.84). Moreover, the risk of death from non- bladder cancer causes also increased, in particular, such as septicemia (SMR 3.09; 95% CI 2.13-4.34). Causes of death during bladder cancer survivorship after surgery vary by patient and tumor characteristics, and these data provide information regarding primary care for women during postoperative cancer survivorship.

A novel in-situ quantitative profiling approach for visualizing changes in lignin and cellulose by stained micrographs.

There is a strong need for low-cost lignocellulosic composition simultaneous localization methodologies to benefit deeper understandings of crop stalk morphology. This study developed a robust quantitative safranin O-fast green staining-based optical microscopy imaging methodology for in-situ simultaneously generating digital profiles of lignin and cellulose in stalk tissues. Foreground extraction and dye residue removal of stained images were adapted. The ratios of normalized red (R), green (G), and blue (B) channel signal intensity, R/B and G/B, were defined as quantitative indicators of lignin and cellulose, respectively. The method was validated on model rice with known bioinformatics, and the results were consistent with those of fluorescence microscopy and immunogold labeling methods. The high-definition spatial in-situ simultaneous profiles of lignin and cellulose in alkali-treated maize stalk tissues and their variations were visualized. This low-cost, cell-scale method is expected to contribute to new discoveries in many areas of biomass refining and plant science.

Forest gaps alter the soil bacterial community of weeping cypress plantations by modulating the understory plant diversity.

Weeping cypress is an endemic tree species that is widely planted in China, and the simple stand structure and fragile ecosystem of its plantation are common issues. Exploring the effect of different gap sizes on the soil bacterial community structure of weeping cypress plantations can provide a theoretical basis for the near-natural management of forest plantations. We, therefore, constructed three kinds of forest gaps with different sizes in weeping cypress plantations, namely, small (50-100 m2), medium (100-200 m2), and large gaps (400-667 m2), for identifying the key factors that affect soil bacterial communities following the construction of forest gaps. The results suggested that the herb layer was more sensitive than the shrub layer, while the Simpson, Shannon, and richness indices of the herb layer in plots with gaps were significantly higher than those of designated sampling plots without any gaps (CK). The presence of large gaps significantly increased the understory plant diversity and the Shannon and Simpson indices of the soil bacterial alpha diversity. There were obvious changes in the community composition of soil bacteria following the construction of forest gaps. The dominant bacterial phyla, orders, and functions were similar across the plots with different gap sizes. Of the indicator bacterial species, the abundance of the nitrogen-fixing bacteria, Lysobacter_ yangpyeongensis, and Ensifer_meliloti, was significantly different across plots with different gap sizes and accounted for a large proportion of the bacterial population of plots with medium and large gaps. The understory plant diversity was mostly related to the soil bacterial community than to other soil factors. The results of structural equation modeling indicated that the understory plant diversity was the most important environmental factor in driving the composition and diversity of bacterial communities. The construction of forest gaps significantly improved the understory plant diversity, physicochemical properties of the soil, and bacterial diversity in weeping cypress plantations, and the results of the comprehensive evaluation were in the order: large gaps > small gaps > medium gaps > CK. Our results suggested that large gaps are beneficial for the diversity of above-ground plant communities and underground soil bacterial communities.

Serum peptidome profiles immune response of COVID-19 Vaccine administration.

Background: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused significant loss of life and property. In response to the serious pandemic, recently developed vaccines against SARS-CoV-2 have been administrated to the public. Nevertheless, the research on human immunization response against COVID-19 vaccines is insufficient. Although much information associated with vaccine efficacy, safety and immunogenicity has been reported by pharmaceutical companies based on laboratory studies and clinical trials, vaccine evaluation needs to be extended further to better understand the effect of COVID-19 vaccines on human beings. Methods: We performed a comparative peptidome analysis on serum samples from 95 participants collected at four time points before and after receiving CoronaVac. The collected serum samples were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to profile the serum peptides, and also subjected to humoral and cellular immune response analyses to obtain typical immunogenicity information. Results: Significant difference in serum peptidome profiles by MALDI-TOF MS was observed after vaccination. By supervised statistical analysis, a total of 13 serum MALDI-TOF MS feature peaks were obtained on day 28 and day 42 of vaccination. The feature peaks were identified as component C1q receptor, CD59 glycoprotein, mannose-binding protein C, platelet basic protein, CD99 antigen, Leucine-rich alpha-2-glycoprotein, integral membrane protein 2B, platelet factor 4 and hemoglobin subunits. Combining with immunogenicity analysis, the study provided evidence for the humoral and cellular immune responses activated by CoronaVac. Furthermore, we found that it is possible to distinguish neutralizing antibody (NAbs)-positive from NAbs-negative individuals after complete vaccination using the serum peptidome profiles by MALDI-TOF MS together with machine learning methods, including random forest (RF), partial least squares-discriminant analysis (PLS-DA), linear support vector machine (SVM) and logistic regression (LR). Conclusions: The study shows the promise of MALDI-TOF MS-based serum peptidome analysis for the assessment of immune responses activated by COVID-19 vaccination, and discovered a panel of serum peptides biomarkers for COVID-19 vaccination and for NAbs generation. The method developed in this study can help not only in the development of new vaccines, but also in the post-marketing evaluation of developed vaccines.

Synthesis and Characterization of Corn Stover-Based Cellulose Triacetate Catalyzed by Ionic Liquid Phosphotungstate.

Cellulose triacetate (CTA) was successfully synthesized from corn stover cellulose (CSC) in the presence of [PyPS]3PW12O40 (IL-POM). The effects of IL-POM contents, reaction temperature, and reaction time on the yield and degree of substitution of CTA were investigated. The synthesized CTA was characterized by SEM, FTIR, and TGA, and the degree of polymerization and solubility in various organic solvents were evaluated. Results showed that the optimum reaction conditions were as follows: 0.04 g of IL-POM, reaction temperature of 140 °C, and reaction time of 45 min, for 0.4 g of CSC and 9 mL of glacial acetic acid. The yield of CTA under optimum reaction conditions was as high as 79.27%, and the degree of substitution was 2.95. SEM and FTIR results showed that the cellulose acetylation occurred, and CTA was synthesized. The TGA results revealed that the decomposition temperature of CTA increased by about 30 °C when compared with that of CSC. A simple, environment-friendly, and efficient process for the preparation of CTA from CSC was constructed, which provides a new pathway for the high-value utilization of corn stover.

Effects of Forest Gaps on the Structure and Diversity of Soil Bacterial Communities in Weeping Cypress Forest Plantations.

The decline in forest ecological function caused by pure forest plantations planted in the Yangtze River basin is becoming increasingly serious. To investigate this problem, we selected the local low-efficiency weeping cypress plantations for forest gap transformation. Three forest gap sizes, specifically large, medium, and small gaps, were established, and the effects of gap sizes on soil bacterial community structure and diversity in winter and summer were studied compared to no gaps (CK; control). Compared to CK, forest gaps had a significant effect on soil organic carbon (SOC) and soil total nitrogen (TN), and the highest values of SOC and soil TN under two seasons occurred in large forest gaps. The interactions of forest gap sizes and seasons had significant effects on pH, SOC, TN, and alpha diversity indices, including Simpson, Chao1, and ACE indices. Compared to winter, forest gaps significantly increased the soil bacterial community diversity indices in summer. Forest gap sizes significantly affected the composition of the bacterial community, but the composition of the dominant bacteria at the phyla and genera levels was similar. Linear discriminant effect size (LEfSe) analysis showed that there were 32 indicator bacterial species in two seasons. Co-occurrence network analysis revealed that the relationship of the soil bacterial community at the phyla level was complex, and there was a significant positive correlation among bacterial species. Soil bulk density (BD) and soil moisture (SM) significantly affected the soil bacterial alpha diversity indices. The composition of the dominant bacteria at the phyla level was significantly affected by soil microbial carbon (MBC), whereas the composition of dominant bacteria at the genera level was affected by soil hydrolysable nitrogen (AN) and the carbon/nitrogen (C/N) ratio. In this study, compared to the other forest gaps, large forest gaps were more conducive to the accumulation of soil nutrients, thus improving the structure of the soil bacterial community. Importantly, changes in the soil bacterial community structure due to gap formation may have profound effects on soil biogeochemical processes in weeping cypress forest plantations.

Sulfated alginate oligosaccharide exerts antitumor activity and autophagy induction by inactivating MEK1/ERK/mTOR signaling in a KSR1-dependent manner in osteosarcoma.

Alginate oligosaccharide (AOS) has the function to inhibit tumor progression and the sulfated modification can enhance the antitumor activity. To date, the function and mechanism of sulfated AOS (AOS-SO4) in tumors remain largely elusive. We prepared AOS by the enzymatic degradation of alginate, collected AOS-SO4 by sulfating following the canonical procedure. Using these materials, in vitro assays showed that both AOS and AOS-SO4 elicited antitumor effects in osteosarcoma cells. Sulfated modification significantly enhanced the antitumor activity. In addition, AOS-SO4 had obvious effects on cell cycle arrest, apoptosis, and autophagy induction in vitro and in vivo. Mechanistically, we observed that AOS-SO4 treatment triggered proapoptotic autophagy by inhibiting MEK1/ERK/mTOR signaling. The ERK activator reversed AOS-SO4-induced autophagy. More importantly, we found that KSR1 interacted with MEK1 and functioned as a positive regulator of MEK1 protein in osteosarcoma cells. High KSR1 expression was significantly associated with poor survival in osteosarcoma patients. Together, these results suggest that AOS-SO4 has a better antitumor effect in osteosarcoma by inhibiting MEK1/ERK/mTOR signaling, which is KSR1-dependent; thus, AOS-SO4 can be a new potential therapeutic candidate for the treatment of osteosarcoma.

Isothermal gene amplification coupled MALDI-TOF MS for SARS-CoV-2 detection.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been spreading worldwide for more than a year and has undergone several mutations and evolutions. Due to the lack of effective therapeutics and long-active vaccines, accurate and large-scale screening and early diagnosis of infected individuals are crucial to control the pandemic. Nevertheless, the current widely used RT-qPCR-based methods suffer from complicated temperature control, long processing time and the risk of false-negative results. Herein, we present a three-way junction induced exponential rolling circle amplification (3WJ-eRCA) combined MALDI-TOF MS assay for SARS-CoV-2 detection. The assay can detect simultaneously the target nucleocapsid (N) and open reading frame 1 ab (orf1ab) genes of SARS-CoV-2 in a single test within 30 min, with an isothermal process (55 °C). High specificity to discriminate SARS-CoV-2 from other coronaviruses, like SARS-CoV, MERS-CoV and bat SARS-like coronavirus (bat-SL-CoVZC45), was observed. We have further used the method to detect pseudovirus of SARS-CoV-2 in various matrices, e.g. water, saliva and urine. The results demonstrated a great potential of the method for large scale screening of COVID-19, which is an important part of the pandemic control.

A MALDI-TOF mass spectrometry-based haemoglobin chain quantification method for rapid screen of thalassaemia.

BACKGROUND: Thalassaemia is one of the most common inherited monogenic diseases worldwide with a heavy global health burden. Considering its high prevalence in low and middle-income countries, a cheap, accurate and high-throughput screening test of thalassaemia prior to a more expensive confirmatory diagnostic test is urgently needed. METHODS: In this study, we constructed a machine learning model based on MALDI-TOF mass spectrometry quantification of haemoglobin chains in blood, and for the first time, evaluated its diagnostic efficacy in 674 thalassaemia (including both asymptomatic carriers and symptomatic patients) and control samples collected in three hospitals. Parameters related to haemoglobin imbalance (α-globin, ß-globin, γ-globin, α/ß and α-ß) were used for feature selection before classification model construction with 8 machine learning methods in cohort 1 and further model efficiency validation in cohort 2. RESULTS: The logistic regression model with 5 haemoglobin peak features achieved good classification performance in validation cohort 2 (AUC 0.99, 95% CI 0.98-1, sensitivity 98.7%, specificity 95.5%). Furthermore, the logistic regression model with 6 haemoglobin peak features was also constructed to specifically identify ß-thalassaemia (AUC 0.94, 95% CI 0.91-0.97, sensitivity 96.5%, specificity 87.8% in validation cohort 2). CONCLUSIONS: For the first time, we constructed an inexpensive, accurate and high-throughput classification model based on MALDI-TOF mass spectrometry quantification of haemoglobin chains and demonstrated its great potential in rapid screening of thalassaemia in large populations.Key messagesThalassaemia is one of the most common inherited monogenic diseases worldwide with a heavy global health burden.We constructed a machine learning model based on MALDI-TOF mass spectrometry quantification of haemoglobin chains to screen for thalassaemia.

Response of plant diversity and soil physicochemical properties to different gap sizes in a Pinus massoniana plantation.

As one means of close-to-nature management, forest gaps have an important impact on the ecological service function of plantations. To improve the current situation of P. massoniana plantations, three different sizes of forest gaps (large gaps, medium gaps and small gaps) were established to observe whether gap setting can improve the soil fertility and plant diversity of forest plantations. The results showed that compared with the control, the soil organic matter content of different soil layers increased significantly in the medium forest gap and large forest gap. The content of soil organic matter in the surface layer of the middle gap had the largest increase (80.64%). Compared with the control, the content of soil-available potassium between different soil layers decreased significantly by 15.93% to 25.80%. The soil hydrolysable nitrogen reached its maximum under the medium gap. Soil moisture showed significant changes among different gap treatments, different soil layers and their interaction, decreasing significantly in large gaps and small gaps but increasing significantly in medium gaps. The soil bulk density decreased significantly compared with the control, and the surface soil reached the minimum in the medium gap. There were different plant species in forest gaps of different sizes, and shrub layer plants were more sensitive to gap size differences than herb layer plants. The plant diversity indices of the shrub layer increased significantly and showed a maximum under the medium gap. The plant diversity of the herb layer showed the opposite trend, and the Shannon-Wiener index, Simpson index and Pielou index were significantly lower than those of the control. RDA showed that different gap treatments had significant effects on the distribution of plants under the forest. Soil available potassium, soil moisture and soil bulk density affected the distribution and diversity of plants under the forest, serving as the limiting factors of plant growth. In forest management, if we strictly consider the improvement of plant diversity and soil physicochemical properties, these results suggest that a medium gap should be established in a plantation for natural restoration.

Early effects of crop tree management on undergrowth plant diversity and soil physicochemical properties in a Pinus massoniana plantation.

BACKGROUND: Soil and understory vegetation are vital components of forest ecosystems. Identifying the interaction of plantation management to vegetation and soil is crucial for developing sustainable plantation ecosystem management strategies. As one of the main measures of close-to-nature management of forest plantation, few studies have paid attention to the effect of crop tree management on the soil properties and understory vegetation. METHODS: A 36-year-old Pinus massoniana plantation in Huaying city, Sichuan Province was taken as the research object to analyse the changes in undergrowth plant diversity and soil physicochemical properties under three different crop tree densities (100, 150, and 200 N/ha). RESULTS: Our results showed that the contents of available phosphorus, organic matter and hydrolysable nitrogen in the topsoil increased significantly after crop tree management, while content of available potassium decreased. The composition of shrub and herb layer was richer, and the dominant species were obviously replaced after crop tree management. The Shannon-Wiener index and Richness index of shrub layer, and the diversity of herb layer increased significantly after crop tree management. Herb layer diversity indexes and Richness index of shrub layer were closely related to soil organic matter, available phosphorus, hydrolysable nitrogen, available potassium, soil moisture and bulk density. As the main limiting factors for plant growth, nitrogen, phosphorus and potassium were closely related to plant diversity and to the distribution of the dominant species. At the initial stage of crop tree management, each treatment significantly improved the soil physicochemical properties and plant diversity of Pinus massoniana plantation, and the comprehensive evaluation was 200 N/ha >100 N/ha >150 N/ha >CK. Compared with other treatments, 200 N/ha had the best effect on improving the undergrowth environment of the Pinus massoniana plantation in the initial stage of crop tree management.