[Tracing investigation and analysis of a Clostridium botulinum food poisoning incident in Bayingolin Mongolian Autonomous Prefecture, Xinjiang]

To analyze a suspected case of Clostridium botulinum food poisoning in Bayingolin Mongolian Autonomous Prefecture, Xinjiang and to help validating the diagnosis and providing technical support for clinical treatment. The basic information and clinical manifestations of food poisoning cases were investigated by using the epidemiological method of food safety accidents. The botulinum toxin genes in the samples were detected by real-time PCR and inoculation of KM mouse. The enriched bacteria were further purified and validated. PFGE and cluster analysis were performed on five isolates. Clostridium botulinum type A was detected in two homemade fermented bean samples and stool lavage fluid samples of three patients from enriched samples by toxin test and real-time PCR, and were further validated after isolation of Clostridium botulinum. PFGE showed 100% homology among five isolates. Five isolates of bacteria isolated from the stool lavage fluid of three patients and two homemade fermented bean curd were identified as the same source through PFGE. The cause of this food poisoning cases is food pollution of Clostridium botulinum type A.

[Combined application of field epidemiology and laboratory etiology analysis in the investigation of a foodborne disease outbreak in Xinjiang uygur Autonomous Region, 2016]

Objectives: To analyze the causes of a foodborne outbreak in rural areas of Xinjiang between April 2 and April 5 in 2016. Methods: Cases and the relevant background information were obtained by consulting outpatient records of local health centers and regional people's hospitals and interviewing doctors and residents. All samples were collected by the laboratory test through epidemiological and food hygiene investigations. The χ² test (Fisher's exact probability method) was used to compare differences in incidence rates. Molecular typing, virulence genes and single nucleotide polymorphisms (SNPS) were analyzed by using Pulsed Field Gel Electrophoresis (PFGE) and Whole Genome Sequencing (WGS). Results: A total of 142 cases were found in this study, with incidence rate at 5.7‰ (142/24 979). Among all cases, the main symptoms were nausea (94%), vomiting (92%) and abdominal pain (67%), and the incubation period was about 2 h (1-7.5 h). There were 16 Staphylococcus aureus isolates identified and all of them could produce A+C+E mixed enterotoxin. PFGE showed 100% homology. WGS further revealed that there were 9 and 1 strains contained by Sequence Type 1 (ST1) and ST5405, respectively. All ST1 strains were in the same clade on the genome tree. Among these, 7 strains shared close proximity (74 SNPs) and 2 strains shared close relationships as well (127 SNPs). The S. aureus isolates that caused the outbreak were introduced by a mutant isolate from the milk supply station. Conclusions: This foodborne outbreak was mainly caused by Staphylococcus aureus contamination.

Parental education and youth suicidal behaviours: a systematic review and meta-analysis

AIMS

Lower parental education has been linked to adverse youth mental health outcomes. However, the relationship between parental education and youth suicidal behaviours remains unclear. We explored the association between parental education and youth suicidal ideation and attempts, and examined whether sociocultural contexts moderate such associations.

METHODS

We conducted a systematic review and meta-analysis with a systematic literature search in PubMed, PsycINFO, Medline and Embase from 1900 to December 2020 for studies with participants aged 0-18, and provided quantitative data on the association between parental education and youth suicidal ideation and attempts (death included). Only articles published in English in peer-reviewed journals were considered. Two authors independently assessed eligibility of the articles. One author extracted data [e.g. number of cases and non-cases in each parental education level, effect sizes in forms of odds ratios (ORs) or beta coefficients]. We then calculated pooled ORs using a random-effects model and used moderator analysis to investigate heterogeneity.

RESULTS

We included a total of 59 articles (63 study samples, totalling 2 738 374 subjects) in the meta-analysis. Lower parental education was associated with youth suicidal attempts [OR = 1.12, 95% Confidence Interval (CI) = 1.04-1.21] but not with suicidal ideation (OR = 1.05, 95% CI = 0.98-1.12). Geographical region and country income level moderated the associations. Lower parental education was associated with an increased risk of youth suicidal attempts in Northern America (OR = 1.26, 95% CI = 1.10-1.45), but with a decreased risk in Eastern and South-Eastern Asia (OR = 0.72, 95% CI = 0.54-0.96). An association of lower parental education and increased risk of youth suicidal ideation was present in high- income countries (HICs) (OR = 1.14, 95% CI = 1.05-1.25), and absent in low- and middle-income countries (LMICs) (OR = 0.91, 95% CI = 0.77-1.08).

CONCLUSIONS

The association between youth suicidal behaviours and parental education seems to differ across geographical and economical contexts, suggesting that cultural, psychosocial or biological factors may play a role in explaining this association. Although there was high heterogeneity in the studies reviewed, this evidence suggests that the role of familial sociodemographic characteristics in youth suicidality may not be universal. This highlights the need to consider cultural, as well as familial factors in the clinical assessment and management of youth's suicidal behaviours in our increasingly multicultural societies, as well as in developing prevention and intervention strategies for youth suicide.

[Analysis on mortality and premature death rates of 4 major chronic diseases in Ji'nan, 2015-2020]

Objective: To understand the characteristics and trend of the premature death rate of 4 major chronic diseases in Ji'nan from 2015 to 2020. Methods: The death cause surveillance data and population data during 2015-2020 in Ji'nan were collected, and abbreviated life table, Joinpoint regression analysis and other methods were used to analyze the characteristics and change trends of the premature death rates of 4 major chronic diseases. Results: The crude mortality rate and age standardized mortality rate changes for the 4 major chronic diseases from 2015 to 2020 range from 568.65/100 000 to 604.06/100 000 and 366.77/100 000 to 432.48/100 000, respectively. The annual premature death rate of 4 major chronic diseases declined by 3.33% averagely from 2015 to 2020 (95%CI: -6.25%--0.32%), which might be explained by the declines of the premature death rates of cardiovascular and cerebrovascular diseases [average annual percentage change (AAPC)=-3.23%, 95%CI: -6.32%--0.05%] and cancer (AAPC=-3.58%,95%CI:-6.83%--0.21%). The average decline rate in women (AAPC=-4.19%,95%CI:-7.56%- -0.70%) was higher than that in men (AAPC=-2.92%,95%CI: -5.65%--0.11%). Conclusions: The premature death rate of 4 major chronic diseases showed a downward trend in Ji'nan from 2015 to 2020. Men should be considered as a key population in the prevention and control of 4 major chronic diseases, and attention should also be paid to the non-significant declines in the premature death rates of chronic respiratory diseases and diabetes.

[Application of bionics in spinal surgery]

Spinal bionic therapy is the application of bionics concept, by imitating the natural anatomical structure and physiological function of the spine, to treat spinal diseases using various modern technology, materials and equipment .How to repair or preserve the anatomical structure and function of spine to the maximum extent while treating spinal diseases is an important content of spinal bionic therapy.Firstly, the use of movable spinal implants not only preserves the spinal mobility function to a certain extent, reduces the degeneration of adjacent segments, but also reduces the incidence of internal fixation fracture and improves the long-term efficacy.Secondly, with the help of the development of three dimensional printing technology, personalized artificial prostheses can be made to fill the spinal structure with complex defects, and biological scaffolds and functional prostheses with anti-tumor drugs can not only realize the biomimetic and functional spine anatomy, but also become a multiplier of the efficacy of anti-tumor drugs.Thirdly, in the design and manufacture of spinal orthopaedic braces, computer aided design and manufacturing technology can make spinal orthopaedic braces more comfortable with better orthopaedic effect and ergonomic characteristics.How to apply bionics concepts and relate technologies to spinal surgery have not been determined yet, and no relevant diagnosis and treatment guidelines have been formulated.It is foreseeable that with the continuous development of medical technology, the content of spinal bionic therapy will be gradually enriched and improved, and become a powerful measure to overcome difficulties in the diagnosis and treatment of spinal surgery diseases.

[Preliminary study on differentially expressed proteins in a mouse model of secondary cystic echinococcosis based on data independent acquisition proteomics]

OBJECTIVE

To identify the differentially expressed proteins in different liver tissues in the mouse model of cystic echinococcosis (CE), so as to provide insights into the research and development of therapeutic drugs targeting CE.

METHODS

Female Kunming mice at ages of 6 to 8 weeks were randomly assigned into the CE group and the control group. Mice in the CE group were intraperitoneally infected with 2 000 Echinococcus multilocularis protoscoleces, while mice in the control group were injected with the same volume of physiological saline. All mice in both groups were sacrificed after breeding for 350 d, and the lesions (the lesion group) and peri-lesion specimens (the peri-lesion group) were sampled from the liver of mice in the CE group and the normal liver specimens (the normal group) were sampled from mice in the control group for data independent acquisition (DIA) proteomics analysis, and the differentially expressed proteins were subjected to Gene Ontology (GO) term enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis.

RESULTS

A total of 26 differentially expressed proteins were identified between the lesion group and the normal group and between the peri-lesion group and the normal group, including 8 up-regulated proteins and 18 down-regulated proteins. GO term enrichment analysis showed that these differentially expressed proteins were predominantly enriched in endoplasmic reticulum membrane (biological components), oxidoreductase activity (molecular function) and oxoacid metabolic process and monocarboxylic acid metabolic process (biological processes). KEGG pathway enrichment analysis revealed that the differentially expressed protein Acyl-CoA oxidase 1 (Acox1), which contributed to primary bile acid biosynthesis during the fatty acid oxidation, was involved in peroxisome signaling pathway, and the differentially expressed protein fatty acid binding protein 1 (Fabp1), which contributed to fatty acid transport, was involved in the peroxisome proliferator-activated receptor (PPAR) signaling pathway.

CONCLUSIONS

Differentially expressed proteins are identified in the liver specimens between mouse models of CE and normal mice, and some differentially expressed proteins may serve as potential drug targets for CE.

[Preliminary study on differentially expressed proteins in a mouse model of secondary alveolar echinococcosis based on data independent acquisition proteomics]

OBJECTIVE

To identify the differentially expressed proteins in different liver tissues in the mouse model of alveolar echinococcosis using high-resolution mass spectrometry with data independent acquisition (DIA), and to identify the key proteins contributing to the pathogenesis of alveolar echinococcosis.

METHODS

Protoscoleces were isolated from Microtus fuscus with alveolar echinococcosis and the experimental model of alveolar echinococcosis was established in female Kunming mice aged 6 to 8 weeks by infection with Echinococcus multilocularis protoscoleces. Mice were divided into the experimental and control groups, and animals in the experimental group was injected with approximately 3 000 protoscoleces, while mice in the control group were injected with the same volume of physiological saline. Mouse liver specimens were sampled from both groups one year post-infection and subjected to pathological examinations. In addition, the lesions (the lesion group) and peri-lesion specimens (the peri-lesion group) were sampled from the liver of mice in the experimental group and the normal liver specimens (the normal group) were sampled from mice in the control group for DIA proteomics analysis, and the differentially expressed proteins were subjected to bioinformatics analysis.

RESULTS

A total of 1 020 differentially expressed proteins were identified between the lesion group and the normal group, including 671 up-regulated proteins and 349 down-regulated proteins, and 495 differentially expressed proteins were identified between the peri-lesion group and the normal group, including 327 up-regulated proteins and 168 down-regulated proteins. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that these differentially expressed proteins were involved in peroxisome, peroxisome proliferator-activated receptor (PPAR) and fatty acid degradation pathways, and the peroxisome and PPAR signaling pathways were found to correlate with liver injury. Several differentially expressed proteins that may contribute to the pathogenesis of alveolar echinococcosis were identified in these two pathways, including fatty acid binding protein 1 (Fabp1), Acyl-CoA synthetase long chain family member 1 (Acsl1), Acyl-CoA oxidase 1 (Acox1), Enoyl-CoA hydratase and 3-hydroxyacyl CoA dehydrogenase (Ehhadh) and Acetyl-Coenzyme A acyltransferase 1B (Acaa1b), which were down-regulated in mice in the experimental group.

CONCLUSIONS

A large number of differentially expressed proteins are identified in the liver of the mouse model of alveolar echinococcosis, and Fabp1, Acsl1, Acox1, Ehhadh and Acaa1b may contribute to the pathogenesis of alveolar echinococcosis.

[Efficacy and safety of venetoclax combined with azacitidine versus CAG regimen combined with decitabine in elderly patients with relapsed acute myeloid leukemia]

Objective: To compare the efficacy and safety of venetoclax (VEN) combined with azacitidine (AZA) versus CAG regimen combined with decitabine (DAC) in elderly patients with relapsed acute myeloid leukemia (AML). Methods: From January 2018 to August 2020, the clinical data of forty-five elderly patients with relapse AML at the First Affiliated Hospital of Soochow University were retrospectively analyzed, including 31 males and 14 females. The median age was 66 (60-80) years old. Eighteen patients were administrated with VEN and AZA, while the other 27 were in CAG with DAC. The complete remission (CR) rate, partial remission (PR) rate, total remission rate (ORR), adverse events and overall survival (OS) were compared between the two groups. Results: At the end of the treatment, the ORR in VEN with AZA group was 77.8% (14/18); including 11 CR and 3 PR. In CAG with DAC group, the ORR was 37.0% (10/27); including 8 CR and 2 PR (P=0.007). Subgroup analysis suggested that VEN with AZA had a higher ORR in patients stratified as intermediate and poor-risk (P=0.013) or with DNA methylation mutations (P=0.007). Main adverse events in both groups were bone marrow suppression, infections, nausea and vomiting, anorexia and fatigue. Grade Ⅲ-Ⅳ cytopenia developed in lower incidence of VEN with AZA group, such as leukopenia (66.7% vs. 100%, P=0.002), anemia (50.0% vs. 92.6%, P=0.002), thrombocytopenia (72.2% vs. 96.3%, P=0.031) and neutropenia (61.1% vs. 92.6%, P=0.014). In addition, less grade Ⅲ-Ⅳ infections occurred in VEN with AZA group (66.7% vs. 33.3%, P=0.028), as well as grade Ⅲ-Ⅳ gastrointestinal events (40.7% vs. 11.1%, P=0.032), grade Ⅲ-Ⅳ fatigue (55.6% vs.11.1%, P=0.003) compared with CAG with DAC group. The 1-year OS in VEN with AZA group versus CAG with DAC group was 42.9% and 31.6% respectively (P=0.150). Conclusion: VEN combined with AZA proves favorable efficacy and tolerablity in elderly patients with relapsed AML.

Association of High Muscle Mass with Carotid Atherosclerosis: A Community-Based Population Cohort Study

OBJECTIVES

Although low muscle mass may make an under-appreciated contribution to increasing the risk of cardiovascular diseases, no prospective studies have explored the association between low muscle mass and carotid atherosclerosis. We investigated whether muscle mass was related to a higher carotid intima-media thickness (C-IMT) and carotid artery plaque in a community-based population.

METHODS

The study included 1,253 asymptomatic participants without known cardiovascular disease, who underwent carotid ultrasonography at baseline in 2013-2014 and received a re-examination in 2015-2016. The skeletal muscle mass index was estimated using a bioelectrical impedance analyzer. We assessed the relationship between the skeletal muscle mass index and the development of C-IMT and carotid plaque, both, using multivariate-adjusted logistic regression models.

RESULTS

During the follow up, 400 (51.0%) subjects with normal C-IMT at baseline developed elevated C-IMT and 215 (17.2%) subjects developed carotid plaque. The risk of elevated C-IMT occurrence linearly decreased with an increase in skeletal muscle mass index quintiles or its continuous data, after multivariate-adjustment in men and women, respectively (both P for trend < 0.05; both P < 0.05). Subgroup analyses showed that this association was BMI-dependent. Besides, there was an inverse association between a high skeletal muscle mass index and carotid artery plaque in women, but the association disappeared after multivariate adjustment. In men, the skeletal muscle mass index was not associated with the incidence of carotid plaque.

CONCLUSIONS

Skeletal muscle mass was inversely associated with the incidence of carotid atherosclerosis, suggesting muscle mass maintenance may play a role in modifying atherosclerosis.

Huaier Polysaccharide Attenuates Doxorubicin-Induced Acute Cardiotoxicity by Regulating Ferroptosis

We studied the effects of Huaier polysaccharide (HP) in doxorubicin-induced myocardial injury in mice. The content of HP in Trametes robiniophila Murr medicinal fungus determined by the phenol-sulfuric acid method was 85.25%. In the in vitro model, the viability of H9c2 cells was significantly increased after HP treatment compared to the control, while doxorubicin (DOX) decreased this parameter. The inhibitory effect of DOX on cell viability was attenuated after HP treatment. In the in vivo model, the body weight of mice in DOX and DOX+HP groups was significantly decreased compared to the control group. ECG showed significantly elevated ST segment in the DOX group, while in the DOX+HP group, ECG was close to normal. The levels of cardiotoxicity markers cTnI and lactate dehydrogenase in the DOX+HP group were significantly lower than in the DOX group. In the DOX group, the myocardial tissue had obvious structural disorder and interfibrillar vacuoles. In the DOX+HP group, the cardiomyocytes were neatly arranged without interfibrillar vacuoles. The expression of the ferroptosis marker glutathione peroxidase 4 was increased in the DOX+HP group compared to the DOX group. Thus, our study reveals that HP attenuated DOX-induced myocardial injury in mice probably by regulating ferroptosis.

Heterozygous Ins/Del genotype of the CASP8 rs3834129 polymorphism significantly decreases the risk of coal workers' pneumoconiosis in a Chinese Han population: a case-control study

OBJECTIVE

Coal workers' pneumoconiosis (CWP) is a chronic inflammatory and fibrotic pulmonary disease that involves a complex interaction of multiple environmental and genetic factors. Polymorphism, as a genetic factor, may affect the onset of the disease in susceptible populations. The present study investigated the association between the polymorphisms of six genes and CWP risk in a Chinese Han population.

PATIENTS AND METHODS

Six polymorphisms (CASP8 rs3834129, IL1A rs1800587, IL6 rs1800796, IL4 rs2070874, TNFA rs361525, and NLRP3 rs1539019) were examined in 222 CWP subjects and 247 dust-exposed control subjects.

RESULTS

The CASP8 rs3834129 Ins/Del genotype significantly decreased CWP risk (p=0.040; adjusted odds ratio [OR] = 0.586; 95% confidence interval [CI] 0.367-0.935) compared with the Ins/Ins genotype. Stratification analyses revealed a significant interaction between the heterozygous Ins/Del genotype and age. Compared with the Ins/Ins + Del/Del genotype, this was particularly evident among subjects aged 41-60 (p<0.001; adjusted OR = 0.054; 95% CI 0.007-0.420) and those with an exposure time of 20-29 years (p=0.014; adjusted OR = 0.392; 95% CI 0.183-0.842). This decreased risk was also found in the group with former smokers (p=0.012; adjusted OR = 0.448; 95% CI 0.238-0.844). Findings revealed that the heterozygous Ins/Del genotype of CASP8 rs3834129 was related to a significantly decreased risk of stage I CWP (p=0.045; adjusted OR = 0.592; 95% CI 0.353-0.992), but not stage II or III CWP.

CONCLUSIONS

Our study indicated that the heterozygous Ins/Del genotype of CASP8 rs3834129 significantly decreased CWP risk in a Chinese Han population.

[Effects of SGLT2i on 24-hour ambulatory blood pressure in patients with type 2 diabetes complicating hypertension: a meta-analysis]

Objective: To analyze the effects of different types of sodium-glucose cotransporter 2 inhibitors (SGLT2i) on 24-hour ambulatory blood pressure in patients with type 2 diabetes mellitus and hypertension. Method: In this meta-analysis, we searched for randomized controlled trials on the effect of SGLT2i on 24-hour ambulatory blood pressure in patients with type 2 diabetes and hypertension. Three databases, namely PubMed, Web of Science and Cochrane Library, were searched. The search was organized on the concept of 3 conceptual groups: the first group contained terms used to describe SGLT2i, the second group contained terms related to blood pressure, and the third group contained terms used to describe randomized controlled trials. The search time was from the establishment of the database to December 2020. The inclusion and exclusion criteria were formulated in accordance with the requirements of the Cochrane systematic review. According to whether the heterogeneity of the study was significant or not, a random effect model or a fixed effect model were used to conduct the analysis on the impact of different types of SGLT2i on 24-hour ambulatory blood pressure and day and night blood pressure in patients with type 2 diabetes and hypertension. Further subgroup analysis was performed to define potential factors, which might lead to clinical heterogeneity. Results: Seven clinical trials were finally included. The result of the meta-analysis showed that compared with placebo group, SGLT2i could reduce the 24-hour dynamic systolic blood pressure of patients with type 2 diabetes and hypertension by 4.36 mmHg (1 mmHg=0.133 kPa). Reduction was 4.59, 3.74, 5.06, and 3.64 mmHg by canagliflozin, dapagliflozin, empagliflozin, and ertugliflozin respectively; SGLT2i could reduce the 24-hour dynamic diastolic blood pressure of patients with type 2 diabetes and hypertension by 2.20 mmHg, and the reduction was 2.30, 1.22, 2.00, and 2.69 mmHg by canagliflozin, dapagliflozin, empagliflozin and ertugliflozin respectively. SGLT2i could reduce the daytime systolic blood pressure of patients with type 2 diabetes and hypertension by 5.25 mmHg, and reduction was 5.38, 4.87, 6.00, and 4.37 mmHg by canagliflozin, dapagliflozin, empagliflozin and ertugliflozin, respectively. Simultaneously, SGLT2i could reduce the diastolic blood pressure of patients with type 2 diabetes and hypertension by 2.62 mmHg, and the reduction was 2.56, 2.47, and 2.80 mmHg by canagliflozin, empagliflozin and ertugliflozin, respectively. SGLT2i could reduce the nighttime systolic blood pressure of patients with type 2 diabetes and hypertension by 3.62 mmHg, and the reduction was 2.09, 2.06, 3.92, and 2.45 mmHg by canagliflozin, dapagliflozin, empagliflozin and ertugliflozin, respectively. At the same time, SGLT2i could reduce the nighttime diastolic blood pressure of patients with type 2 diabetes and hypertension by 1.60 and 1.51 mmHg, the reduction was 1.53 and 2.58 mmHg by canagliflozin, empagliflozin and ertugliflozin, respectively. Conclusion: SGLT2i can reduce 24-hour ambulatory blood pressure in patients with type 2 diabetes and hypertension.

Modeling Kelvin-Helmholtz Instability at the High-Latitude Boundary Layer in a Global Magnetosphere Simulation

The Kelvin-Helmholtz instability at the magnetospheric boundary plays a crucial role in solar wind-magnetosphere-ionosphere coupling, particle entry, and energization. The full extent of its impact has remained an open question due, in part, to global models without sufficient resolution to capture waves at higher latitudes. Using global magnetohydrodynamic simulations, we investigate an event when the Magnetospheric Multiscale (MMS) mission observed periodic low-frequency waves at the dawn-flank, high-latitude boundary layer. We show the layer to be unstable, even though the slow solar wind with the draped interplanetary magnetic field is seemingly unfavorable for wave generation. The simulated velocity shear at the boundary is thin ( ∼ 0.65 R E ) and requires commensurately high spatial resolution. These results, together with MMS observations, confirm for the first time in fully three-dimensional global geometry that KH waves can grow in this region and thus can be an important process for energetic particle acceleration, dynamics, and transport.

[Controversial issues of chronic ankle instability]

Chronic ankle instability is a chronic sports injury disease characterized by recurrent sprains, feeling of instability, pain, swelling and other symptoms after an initial sprain. Research on the pathological mechanism of chronic ankle instability still cannot explain the diversity of symptoms. In the past, the surgical indications for chronic ankle instability only emphasized mechanical joint laxity. However, most patients with chronic symptoms after a lateral ankle sprain may not have a typical complaint of mechanical instability. More patients presented with persistent pain or functional instability as the chief complaint. Surgical treatment also has a certain effect on the symptoms of functional instability, but the surgical indications of functional instability are mainly based on subjective symptoms. At present, there is a lack of objective indicators for surgery, which is still controversial. Further in-depth research on the mechanism of chronic ankle instability is needed to guide the formulation of diagnosis and treatment strategies.

Organic carbon quantity and quality jointly triggered the switch between dissimilatory nitrate reduction to ammonium (DNRA) and denitrification in biofilters

The effect of organic carbon (OC) quality and quantity on switch between dissimilatory nitrate reduction to ammonium (DNRA) and denitrification (DEN) was studied in biofilter systems. High OC in matrix could promote significantly nitrate (NO₃^--N) removal due to the reinforce of DEN. Sodium acetate (SA) addition in influent further fueled NO₃^--N removal in groups with low OC in matrix but increased ammonium (NH₄⁺-N) and nitrite (NO₂^--N) accumulation in groups with high OC in matrix. This indicated that high OC combined different species, facilitated the DNRA over DEN. Compared to bagasse, corncob was the better suitable OC source in matrix for DEN due to slow and continuous release of OC. Hence, in order to promote NO₃^--N removal and decline NH₄⁺-N accumulation in biofilters, it is very important to screen suitable OC source (mixed utilization of multiple C sources is recommended) and regulate its dosage (below 80 mg L^-1).