Long-term impact of socioeconomic status after acute myocardial infarction in Korea.

BACKGROUND AND AIMS: Socioeconomic status (SES) is known to impact the prognosis of acute myocardial infarction (AMI). However, due to the limited scope of previous studies, this study aimed to investigate the impact of SES on the prognosis of AMI patients within the Korean national healthcare insurance system. METHODS AND RESULTS: A retrospective cohort study included patients who were diagnosed with AMI between 2007 and 2008 from the Korean National Health Insurance Service and underwent a national health check-up program. Primary endpoint was all-cause mortality. The median follow-up duration was 13.5 years. The SES was divided into tertile scale based on insurance premiums and economic status. Tertile 1 (T1) was the lowest SES, and tertile 3 (T3) was the highest SES. A total of 5971 patients were included, of whom 4329 were employed insured (EI), and 1642 were self-employed insured (SI). After adjusted confounding variables, the Cox-regression model showed SI was associated with worse outcome compared with EI (hazard ratio (HR) [95 % confidence intervals (CIs)], 1.11 [1.02-1.22]). Among individuals in EI, lower economic status showed a trend of worse outcome, but it was not significant (lower tertile vs. higher tertile group, HR [95 % CIs], 1.01 [0.88-1.14]). However, compared with T3 in SI, HRs (95 % CIs) for all-cause death in T2 and T1 were 1.33 (1.09-1.63) and 1.34 (1.10-1.64), respectively. CONCLUSION: SES significantly affected the long-term outcome in patients with AMI. SI and lower economic status in SI were associated with a higher mortality rate than EI and higher economic status, respectively. Further investigation of the underlying role of SES in increased mortality after AMI is warranted.

Higher high-density lipoprotein cholesterol levels increased vertebral osteoporotic fracture, but reduced hip fracture in men based on the National Health Insurance Service-National Health Screening Cohort.

BACKGROUND CONTEXT: Lipids are currently known to play an important role in bone metabolism. PURPOSE: This study aimed to investigate the effect of high-density lipoprotein cholesterol (HDL-C) on osteoporotic fractures beyond its beneficial effects on the cardiovascular system. STUDY DESIGN/SETTING: This was a retrospective, observational study that used data from the National Health Insurance Service-Health Screening cohort database. PATIENT SAMPLE: This study included 318,237 participants who were 50 years or older and with HDL-C levels of 10 to 200 mg/dL. OUTCOMES MEASURES: Physiologic measure-Diagnosis of osteoporotic fracture during the follow-up period. METHODS: The study participants were categorized into four quartiles according to baseline HDL-C levels. The Cox proportional hazards model was used to assess osteoporotic fracture risk according to HDL-C levels. RESULTS: After full adjustment and with the Q1 group as the reference group, estimates of hazard ratios (HRs; 95% confidence intervals [CIs]) for any osteoporotic fracture in men were 1.03 (0.94-1.12), 1.02 (0.93-1.11), and 1.07 (0.98-1.18) for the Q2, Q3, and Q4 groups, respectively. After classifying osteoporotic fractures according to the body location, the fully adjusted HRs for vertebral and hip fractures in the men's Q4 groups were 1.16 (1.02-1.31) and 0.74 (0.57-0.96), respectively. In women, fully adjusted HRs (95% CIs) of the female Q4 group for any osteoporotic, vertebral, and hip fractures were 1.03 (0.95-1.11), 0.96 (0.86-1.07), and 1.06 (0.80-1.41), respectively. CONCLUSION: In this study, HDL-C levels were positively associated with vertebral fractures in both men and women but inversely related to hip fractures in men. Therefore, monitoring the lipid profiles of patients with osteoporosis may be beneficial for the prevention of osteoporotic fractures.

Pharmacological Evidence Suggests That Slo3 Channel Is the Principal K+ Channel in Boar Spermatozoa.

Sperm ion channels are associated with the quality and type of flagellar movement, and their differential regulation is crucial for sperm function during specific phases. The principal potassium ion channel is responsible for the majority of K+ ion flux, resulting in membrane hyperpolarization, and is essential for sperm capacitation-related signaling pathways. The molecular identity of the principal K+ channel varies greatly between different species, and there is a lack of information about boar K+ channels. We aimed to determine the channel identity of boar sperm contributing to the primary K+ current using pharmacological dissection. A series of Slo1 and Slo3 channel modulators were used for treatment. Sperm motility and related kinematic parameters were monitored using a computer-assisted sperm analysis system under non-capacitated conditions. Time-lapse flow cytometry with fluorochromes was used to measure changes in different intracellular ionic concentrations, and conventional flow cytometry was used to determine the acrosome reaction. Membrane depolarization, reduction in acrosome reaction, and motility parameters were observed upon the inhibition of the Slo3 channel, suggesting that the Slo3 gene encodes the main K+ channel in boar spermatozoa. The Slo3 channel was localized on the sperm flagellum, and the inhibition of Slo3 did not reduce sperm viability. These results may aid potential animal-model-based extrapolations and help to ameliorate motility and related parameters, leading to improved assisted reproductive methods in industrial livestock production.

Hexane fraction of Prunus japonica thunb. Seed extract enhances boar sperm motility via CatSper ion channel.

Introduction: Mammalian sperm motility is facilitated by flagellar beating, which depends on active ion movement through ion channels and their regulation. Prunus japonica Thunb., also known as oriental bush cherry, is a widely used traditional medicinal plant. However, its significance in improving fertility and sperm quality has not been fully elucidated yet. One of our previous reports revealed that P. japonica seed extract (PJE) can improve human sperm motility through intracellular pH modulation. Aim of the study: The present study was designed to investigate the effects of PJE on boar spermatozoa and potential underlying mechanisms. Materials and methods: Sperm motility changes were examined using a computer-assisted sperm analysis (CASA) system under both capacitated and non-capacitated conditions. Intracellular calcium concentration was measured using either confocal microscopy or a fluorescent microplate reader with Fluo-4AM calcium fluorescent dye. Sperm capacitation-related proteins were analyzed using western blotting. Results: A significant increase in rapid motility, velocity, and linear displacement of sperm was observed in PJE-treated capacitated boar sperm, whereas the effect was insignificant in the non-capacitated counterparts. Intracellular calcium levels were significantly elevated upon PJE treatment (20-100 µg/L) in a concentration-dependent manner. The increase in intracellular calcium levels was inhibited when the sperm were treated with a CatSper (cation channel of sperm) channel inhibitor, 10 µM Mibefradil, indicating the involvement of the ion channel in the PJE modulatory mechanism. In addition, western blotting revealed an increased level of protein phosphorylation (p-tyrosine and p-PKA), which is a hallmark of sperm capacitation. Conclusions: PJE treatment resulted in a combination of increased motility, intracellular calcium concentration, and capacitation, thereby indicating its potential to ameliorate sperm motility parameters and induce capacitation of boar spermatozoa as a result of intracellular calcium elevation via the CatSper channel. Our observations further elaborate ion channel-related underlying mechanisms and show putative implications of the seed extract of traditionally used P. japonica Thunb. in ameliorating sperm quality.

Maternal Bochdalek Hernia during Pregnancy: A Systematic Review of Case Reports.

BACKGROUND: Since the first report of a diaphragmatic hernia from Ambroise Paré's necropsy in 1610, the Bochdalek hernia (BH) of the congenital diaphragmatic hernia (CDH) has been the most common types with high morbidity and mortality in the neonatal period. Due to the nature of the disease, CDH associated with pregnancy is too infrequent to warrant reporting in the literature. Mortality of obstruction or strangulation is mostly due to failure to diagnose symptoms early. DATA SOURCES AND STUDY SELECTION: A systematic literature search of maternal BH during pregnancy was conducted using the electronic databases (PubMed and EMBASE) from January 1941 to December 2020. Because of the rarity of the disease, this review included all primary studies, including case reports or case series that reported at least one case of maternal BH in pregnant. Searches, paper selection, and data extraction were conducted in duplicate. The analysis was performed narratively regardless of the control groups' presence due to their rarity. RESULTS: The search retrieved 3450 papers, 94 of which were deemed eligible and led to a total of 43 cases. Results of treatment showed 16 cases in delayed delivery after hernia surgery, 10 cases in simultaneous delivery with hernia surgery, 3 cases in non-surgical treatment, and 14 cases in hernia surgery after delivery. Of 16 cases with delayed delivery after hernia surgery, 13 (81%) cases had emergency surgery and three (19%) cases had surgery after expectant management. Meanwhile, 10 cases underwent simultaneous delivery with hernia surgery, 6 cases (60%) had emergent surgery, and 4 cases (40%) had delayed hernia surgery after expectant management. 3 cases underwent non-surgical treatment. In this review, the maternal death rate and fetal/neonatal loss rate from maternal BH was 5% (2/43) and 16% (7/43), respectively. The preterm birth rate has been reported in 35% (15/43) of maternal BH, resulting from maternal deaths in 13% (2/15) of cases and 6 fetal loss in 40% (6/15) of cases; 44% (19/43) of cases demonstrated signs of bowel obstruction, ischemia, or perforation of strangulated viscera in the operative field, resulting from maternal deaths in 11% (2/19) of cases and fetal-neonatal loss in 21% (4/19) of cases. CONCLUSION: Early diagnosis and surgical intervention are imperative, as a gangrenous or non-viable bowel resection significantly increases mortality. Therefore, multidisciplinary care should be required in maternal BH during pregnancies that undergo surgically repair, and individualized care allow for optimal results for the mother and fetus.

Cygnus X-1 contains a 21-solar mass black hole-Implications for massive star winds.

The evolution of massive stars is influenced by the mass lost to stellar winds over their lifetimes. These winds limit the masses of the stellar remnants (such as black holes) that the stars ultimately produce. We used radio astrometry to refine the distance to the black hole x-ray binary Cygnus X-1, which we found to be [Formula: see text] kiloparsecs. When combined with archival optical data, this implies a black hole mass of 21.2 ± 2.2 solar masses, which is higher than previous measurements. The formation of such a high-mass black hole in a high-metallicity system (within the Milky Way) constrains wind mass loss from massive stars.

Chemical analysis techniques and investigation of polycyclic aromatic hydrocarbons in fruit, vegetables and meats and their products.

The current investigation was performed to evaluate the chemical analytical techniques for PAHs (organic, carcinogenic and mutagenic compounds) in food. It also determines the content of eight polycyclic aromatic hydrocarbons (PAHs) in frequently consumed fruit, vegetables, meats and their products. The methodology included saponification or ultrasonication, liquid-liquid extraction with solvents like n-hexane, clean-up using a silica solid phase extraction cartridge and a gas chromatography-mass spectrometry technique. A good linearity (R2 > 0.99) was achieved for the PAHs at different concentrations. Recovery results for PAHs extended from 88.75 to ∼100.00%. The limit of detection was 0.08-0.25 µg/kg and the limit of quantification was 0.24-0.75 µg/kg. The mean concentration (n = 3) of benzo[a]pyrene was not identified in fruits, was 0.05 µg/kg in vegetables, and 0.64 µg/kg in meat products. Overall concentration of the eight PAHs was 0.67 µg/kg in fruits, 0.82 µg/kg in vegetables, and 3.37 µg/kg in meat products.

Development and validation of an instrument to assess knowledge and skills of evidence-based nursing.

AIMS AND OBJECTIVES: To develop an objective instrument to measure nurses' entry-level knowledge of and skills in evidence-based practice, and to evaluate the validity and reliability of the instrument. BACKGROUND: To promote evidence-based practice in nursing, nurses should initially receive education about evidence-based practice knowledge and learn the skills, and this should be followed by measurement with an instrument that was developed to evaluate the extent to which they are prepared to use evidence-based practice knowledge and skills. Although some self-report instruments have been developed to measure evidence-based practice in nursing, an objective instrument to evaluate nurses' evidence-based practice knowledge and skills is not available at present. DESIGN: A methodological study. METHODS: This study was conducted in two stages: the instrument development and its psychometric evaluation, including its validity and reliability. An instrument, 'Knowledge and Skills of Evidence-based Nursing,' was developed. Content validity was assessed by five experts in evidence-based nursing, and the construct validity was evaluated by the known-groups method. Reliability was examined with internal consistency reliability and inter-rater reliability. RESULTS: A content validity index >0·80 was achieved. For construct validity, there were statistically significant differences between the evidence-based practice and nonevidence-based practice groups in total scores and in the scores on each subscale of the Knowledge and Skills of Evidence-based Nursing. Cronbach's alpha was 0·96, and the inter-rater reliability was excellent. CONCLUSIONS: The Knowledge and Skills of Evidence-based Nursing is a valid and reliable instrument for objectively assessing nurses' evidence-based practice knowledge and skills; it is quick to complete and to score the answers. RELEVANCE TO CLINICAL PRACTICE: Because the Knowledge and Skills of Evidence-based Nursing objectively assesses nurses' evidence-based practice knowledge and skills, it can be used to examine the effects of evidence-based practice education. Moreover, the Knowledge and Skills of Evidence-based Nursing may contribute to the promotion of evidence-based practice projects in clinical settings because it can measure the extent to which nurses are prepared to use their evidence-based practice knowledge and skills.

Effect of blood volume in standard anaerobic blood culture bottles of the BacT/ALERT 3D system used for the detection of pathogens and time to detection.

BACKGROUND: Blood volume may profoundly affect the isolation of microorganisms in blood cultures. The effect of blood volume in standard anaerobic bottles of the BacT/ALERT 3D system was investigated. METHODS: Adult patients who visited the emergency department and referred for blood culture (n = 824) were enrolled from June to September 2013. Two sets of blood cultures were obtained from each patient. One set consisted of 5 mL that was collected in a standard aerobic bottle (SA5), 5 mL that was collected in a standard anaerobic bottle (SN5), and 10 mL that was collected in a standard anaerobic bottle (SN10). The growth of clinically significant pathogens and the time to detection (TTD) were compared between the SN5 and SN10 samples. RESULTS: Increasing the volume of blood collected from 5 to 10 mL yielded a 14.7% improvement in the isolation of microorganisms. There was a statistically significant difference in the isolation of pathogens (14 vs. 30, P = 0.023) between the SN5 and SN10 samples. Gram-positive microorganisms were detected earlier in the SN10 samples than the SN5 samples (P = 0.052). The mean TTD of all pathogens was 13.5 h for the SN5 samples and 12.9 h for the SN10 samples (P = 0.099). CONCLUSION: Increased blood volume in the SN bottle yielded a significantly higher pathogen detection rate. However, there was no difference in the frequency of earlier detection or TTD between the SN5 and SN10 samples.

Development of a simultaneous lateral flow strip test for the rapid and simple detection of deoxynivalenol and zearalenone.

UNLABELLED: The objective of this study was to develop a 1-step simultaneous lateral flow strip test for the rapid and simple detection of deoxynivalenol (DON) and zearalenone (ZEA) in grains. Two monoclonal antibodies (MAbs) against DON and ZEA were respectively conjugated with gold nanoparticles and used to develop a lateral flow strip test for a single toxin and multiple toxins. First, individual lateral flow strips for a single toxin were optimized, and their conditions were used to develop a simultaneous lateral flow strip for multiple toxins. Limits of detection of both lateral flow strip tests for DON and ZEA were the same (DON: 50 ng/mL, ZEA: 1 ng/mL). Both methods showed cross-reactivity for α-zearalenol and ß-zearalenol, but no cross-reaction to other mycotoxins. The results can be completed obtained within 15 min. The cut-off values of the simultaneous lateral flow strip for the spiked rice and corn were 500 and 10 ng/g for DON and ZEA, respectively. The results demonstrated that the developed simultaneous lateral flow strip test offers a rapid, easy-to-use, and portable analytical system and can be used as a convenient qualitative tool for the on-site detection of DON and ZEA in food and agricultural commodities. PRACTICAL APPLICATION: Simultaneous lateral strip test is useful for a rapid detection of DON and ZEA at a time in food and grain samples.

Rapid and sensitive immunochromatographic strip for on-site detection of sulfamethazine in meats and eggs.

A rapid immunochromatographic (ICG) strip based on a conjugate of colloidal gold and monoclonal antibody (mAb) was developed for the rapid, sensitive, and on-site detection of sulfamethazine in meat and egg samples. The detection limit of the ICG strip is 2 ng/mL, and the assay can be completed in 10 min. A cross-reactivity test indicated that the ICG strip was highly specific to sulfamethazine with no cross-reaction with sulfonamide compounds and other antibiotics. The results of the recovery test from meat and egg samples spiked with sulfamethazine were in good agreement with those obtained by the indirect competitive enzyme-linked immunosorbent assay. These results demonstrated that the ICG strip can be used as a rapid and qualitative tool for on-site screening of sulfamethazine in meat and egg samples.

Antihyperglycemic effects of fruits of privet (Ligustrum obtusifolium) in streptozotocin-induced diabetic rats fed a high fat diet.

The protective effects of freeze-dried privet (Ligustrum obtusifolium) fruits (PFs) were observed in streptozotocin (STZ)-induced diabetic rats on a high fat diet by measuring levels of blood glucose, serum insulin, fructosamine, and hepatic reactive oxygen species generating and scavenging enzyme activities. A PF-supplemented diet was prepared by mixing an AIN-76 diet with powdered PF (final concentration, 1% or 2%). It was fed to STZ-induced diabetic rats on a high fat diet for 6 weeks. Diabetic animals receiving the PF-supplemented diet showed a significant increase in body weight, feed efficiency ratio, liver, kidney, and heart weight, and serum glucose, insulin, and fructosamine levels compared with high fat diet-fed diabetic animals. The treatment with PF showed improved hepatic glutathione S-transferase, superoxide dismutase, and xanthine oxidase activities as well as glutathione and lipid peroxide levels in the diabetic animals. Intracellular swelling and vacuole formation in diabetic pancreatic beta- and delta-cells were ameliorated by the PF-supplemented diet. Furthermore, necrosis of tubular epithelial cells and dilatation of luminal space in diabetic kidneys exhibited near-noninjured condition. This is the first time an antihyperglycemic effect of L. obtusifolium fruit in STZ-induced diabetic rats has been identified.

Antihyperglycemic effect of Fomitopsis pinicola extracts in streptozotocin-induced diabetic rats.

The antihyperglycemic effect of a water extract (WE) and an alkali extract (AE) of the Fomitopsis pinicola fruit body was studied in streptozotocin (STZ)-induced diabetic rats. The STZ-induced diabetes mellitus (DM) control group lost a significant amount of body weight, whereas the normal control group (NC) gained weight; however, the DM-AE group gained a significant amount of weight, with weight gain approaching normal. Feed intake by the DM-AE group was also similar to the NC group. The liver and kidney weights per body weight increased with the STZ treatment; however, the weights were lower in the F. pinicola-treated groups and nearly normalized in the DM-AE group. The weights of the heart, lungs, and spleen were not influenced by the STZ treatment. Blood glucose levels of F. pinicola-treated DM groups were significantly lower than that of the DM group. In particular, STZ-induced hyperglycemia was remarkably inhibited by the AE-supplemented diet. Serum insulin levels were decreased with STZ injection; however, the decreased levels were almost restored to the NC level with F. pinicola supplementation. The increased serum fructosamine levels associated with hyperglycemia were decreased with the F. pinicola treatment. Cells of the pericentral regions were found to have significant swelling, and some necrotic cells were observed in the pancreas of DM animals; however, pancreatic tissue damage by STZ in the F. pinicola-supplemented diet groups was ameliorated. In this study, the AE from F. pinicola showed the highest antidiabetic effect among the treatments. These results indicate that constituents of F. pinicola may regulate hyperglycemia via either increased insulin secretion during recovery or the prevention of STZ-induced pancreatic damage. This is the first report of antihyperglycemic effects of F. pinicola in STZ-induced DM rats.

Electrospun PVA/HAp nanocomposite nanofibers: biomimetics of mineralized hard tissues at a lower level of complexity.

Based on the biomimetic approaches the present work describes a straightforward technique to mimic not only the architecture (the morphology) but also the chemistry (the composition) of the lowest level of the hierarchical organization of bone. This technique uses an electrospinning (ES) process with polyvinyl alcohol (PVA) and hydroxyapatite (HAp) nanoparticles. To determine morphology, crystalline structures and thermal properties of the resulting electrospun fibers with the pure PVA and PVA/HAp nanocomposite (NC) before electrospinning various techniques were employed, including transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). In addition, FT-IR spectroscopy was carried out to analyze the complex structural changes upon undergoing electrospinning as well as interactions between HAp and PVA. The morphological and crystallographic investigations revealed that the rod-like HAp nanoparticles exhibit a nanoporous morphology and are embedded within the electrospun fibers. A large number of HAp nanorods are preferentially oriented parallel to the longitudinal direction of the electrospun PVA fibers, which closely resemble the naturally mineralized hard tissues of bones. Due to abundant OH groups present in PVA and HAp nanorods, they strongly interact via hydrogen bonding within the electrospun PVA/HAp NC fibers, which results in improved thermal properties. The unique physiochemical features of the electrospun PVA/HAp NC nanofibers prepared by the ES process will open up a wide variety of future applications related to hard tissue replacement and regeneration (bone and dentin), not limited to coating implants.

Gadolinium-chlorin is potentially a new tumor specific MRI contrast agent.

In this study, a newly-synthesized metalloporphyrin, Gd-chlorin (PB Chlorin), was investigated by using a simple tissue phantom to test its efficacy as an MRI contrast agent. This study demonstrated the potential activity of Gd-chlorin as not only a MRI contrast agent, but also as a PDT photosensitizer by using a simple tissue phantom and conducting a very brief MRI experiment.

Effectiveness of reality therapy program for schizophrenic patients.

PURPOSE: The present study aims to verify the effectiveness of the reality therapy for patients with schizophrenia. METHODS: It is designed as a quasi-experimental study by which a nonequivalent control group pretest-posttest is conducted. The test was conducted with 30 patients with schizophrenia who were hospitalized at a mental hospital in South Korea. Fifteen of the patients participated in the reality therapy program while another 15 in the control group. The effects are measured by marking scores in the areas of the locus of control, self-esteem, and problem-focused stress coping of each participant. RESULTS: The general characteristics and dependent variables related to outcome variables were controlled to be equal between the two groups. It turns out that the internal locus of control, self-esteem, and problem-focused stress coping are statistically significant. CONCLUSION: Findings show that the reality therapy caused positive changes in terms of the internal locus of control, self-esteem, and problem-focused stress coping of the observed schizophrenic patients.

Polymorphisms in genes coding for enzymes metabolizing smoking-derived substances and the risk of periodontitis.

OBJECTIVES: Although the direct cause for periodontitis is oral bacterial infection, its progression depends upon genetic and environmental factors. Smoking, one of the environmental factors, is a risk factor for the development and severity of periodontitis. Therefore, individual susceptibility to periodontitis may be influenced by the polymorphisms of genes coding for enzymes metabolizing tobacco-derived substances. The object of this study is to investigate roles of genetic polymorphisms of these metabolizing enzymes in the risk for periodontitis. MATERIAL AND METHODS: We investigated three important enzymes: cytochrome P450 (CYP) 1A1, CYP2E1 and glutathione S-transferase (GST) M1, involved in the metabolic activation and detoxification of tobacco-derived substances. The prevalence of the polymorphisms of these genes was examined in 115 patients with periodontitis as well as in 126 control subjects. RESULTS: Significantly increased risk for periodontitis was observed for subjects with the polymorphic CYP1A1 m2 allele (odds ratio (OR)=2.3, 95% confidence interval (CI)=1.2-4.4). A significant risk increase for periodontitis associated with the GSTM1 allele was observed (OR=2.1, 95% CI=1.3-3.6). However, no association was observed between the CYP2E1 Pst1 polymorphism and risk for periodontitis (OR=1.3, 95% CI=0.6-2.5). CONCLUSION: These results suggest that the GSTM1 and CYP1A1 polymorphisms may play an important role in risk for periodontitis.

Effect of Alcaligenes faecalis on nitrous oxide emission and nitrogen removal in three phase fluidized bed process.

Nitrous oxide (N2O), one of the greenhouse effect gases, has not been known that how much N2O is produced from municipal wastewater treatment and what its management should be. In this study, for controlling nitrous oxide emission and removing nitrogen from municipal wastewater, we experimented the three phase fluidized bed process equipped with draft tube along with immobilized Alcaligenes faecalis, a typical heterotrophic nitrifer and a predominant genus. Also we evaluated the optimum treatment condition of the three phase fluidized bed process for emitting nitrous oxide. The results of this study showed that the three phase fluidized bed process was more effective than the activated sludge process for controlling nitrous oxide emission and removing nitrogen. Increasing amount of A. faecalis in reactor should be encouraged for controlling nitrous oxide emission and removing nitrogen. In addition, the activated sludge process using immobilized A. faecalis as a carrier had more nitrogen removal efficiency than conventional activated sludge process. The accumulation of NO2-N, NO3-N resulted in high N2O emission. Therefore, we suggested that it is necessary to reduce NO2-N and NO3-N for both reducing N2O emission and improving nitrogen removal.