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OBJECTIVE: This study aims to investigate the diagnostic value of three-dimensional pelvic ultrasound in the preoperative assessment of anal fistula compared with findings of MRI and surgery. METHODS: A total of 67 patients (62 males) with suspected anal fistula were analyzed retrospectively. Preoperative three-dimensional pelvic ultrasound and magnetic resonance imaging were performed in all patients. The number of internal openings and the type of fistula were recorded. The accuracy of three-dimensional pelvic ultrasound was determined by comparing these parameters with surgical outcomes. RESULTS: At surgery, 5 (6%) were extrasphincteric, 10 (12%) were suprasphincteric, 11 (14%) were intersphincteric, and 55 (68%) were transsphincteric. There was no significant difference in the accuracy of pelvic 3D US and MRI, based on internal openings (97.92%, 94.79%), anal fistulas (97.01%, 94.03%), and those under Parks classification (97.53%, 93.83%). CONCLUSION: Three-dimensional pelvic ultrasound is a reproducible and accurate method for determining the type of fistula and detecting internal openings and anal fistulas.
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Endossonografia , Fístula Retal , Masculino , Humanos , Estudos Retrospectivos , Endossonografia/métodos , Imageamento Tridimensional , Fístula Retal/cirurgia , Ultrassonografia , Canal Anal/diagnóstico por imagemRESUMO
Niclosamide is an FDA-approved anthelmintic drug for the treatment of parasitic infections. However, over the past few years, increasing evidence has shown that niclosamide could treat diseases beyond parasitic diseases, which include metabolic diseases, immune system diseases, bacterial and viral infections, asthma, arterial constriction, myopia, and cancer. Therefore, we systematically reviewed the pharmacological activities and therapeutic prospects of niclosamide in human disease and cancer and summarized the related molecular mechanisms and signaling pathways, indicating that niclosamide is a promising therapeutic player in various human diseases, including cancer.
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Anti-Helmínticos , Neoplasias , Doenças Vasculares , Humanos , Niclosamida/farmacologia , Niclosamida/uso terapêutico , Neoplasias/tratamento farmacológico , Anti-Helmínticos/farmacologia , Anti-Helmínticos/uso terapêutico , Transdução de Sinais , Doenças Vasculares/tratamento farmacológicoRESUMO
OBJECTIVE: The purpose of this study was to evaluate the different components of left atrial (LA) dysfunction predictors in asymptomatic primary systemic hypertension patients with preserved left ventricular (LV) ejection fraction, particularly using LA 4-dimensional (4D) longitudinal and circumferential strain values. METHODS AND RESULTS: Patients with no left ventricular hypertrophy (NLVH) and left ventricular hypertrophy (LVH) are all asymptomatic regarding primary blood hypertension. Thirty NLVH patients and 30 LVH patients according to LV mass index and 40 controls analyzed by 4D echocardiography were prospectively enrolled. LA volumes and longitudinal and circumferential strains were measured using 4D volume-strain echocardiography with a Vivid E95 Version 203 instrument. Correlation analysis indicated a significant relation between LV 4D mass index and LA 4D longitudinal/circumferential strain (r = -0.446 to 0.381, p = 0.000-0.042). LVH patients had a reduced LA emptying fraction compared with NLVH patients and control subjects (p < 0.01). NLVH patients had an impaired LA conduit function and increased contractile function compared with the control group (p < 0.01). LVH patients had increased LA volumes and significantly decreased reservoir, conduit and contractile functions compared with the controls (p < 0.01). LVH patients had increased LA volumes and decreased reservoir and contractile functions compared with NLVH patients (p < 0.01). The clinical utility of LA 4D volume-strain measurement was verified by receiver-operating characteristic curve analysis showing larger net benefits as evaluated with NLVH, LVH and control group comparisons. Interclass correlation coefficients of interobserver and intraobserver assessments in the LV and LA 4D value evaluations were >0.75 and >0.85, respectively. CONCLUSIONS: LVH patients showed increased LA volumes and decreased LA emptying fractions. LA reservoir, conduit and contractile functions were significantly impaired in LVH patients. Decreased LA conduit function and increased contractile function were revealed in NLVH patients. LA volumetric and functional analyses with 4D volume-strain echocardiography may facilitate the recognition of subtle LA and LV dysfunctions in asymptomatic systemic hypertension patients.
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Função do Átrio Esquerdo/fisiologia , Ecocardiografia Quadridimensional/métodos , Átrios do Coração/diagnóstico por imagem , Hipertensão/fisiopatologia , Hipertrofia Ventricular Esquerda/fisiopatologia , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Hipertensão/complicações , Hipertensão/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/etiologia , Masculino , Pessoa de Meia-Idade , Volume Sistólico , Função Ventricular EsquerdaRESUMO
Background and aim: New quantitative ultrasound techniques can be used to quantify hepatic steatosis, including tissue attenuation imaging (TAI), tissue scatter -distribution imaging (TSI), and the hepatorenal index (HRI). However, the measurement norms and the effects of fasting on these measurements remain unclear. The present study performed a methodological exploration and investigated the reliability of these measurements. Methods: In total, 103 participants were prospectively recruited for ultrasonography and magnetic resonance imaging (MRI) scans. For the TAI and TSI data, the upper (2 cm), middle (4 cm) and lower (6 cm) areas determined according to the depth of the region of interest from the liver capsule, were sampled three times. Correlation analyses were performed to compare the measurements of TAI, TSI, and HRI with the controlled attenuation parameter (CAP) or MRI-proton density fat fraction (MRI-PDFF). Intra- and inter-operator repeatability was assessed using intraclass correlation coefficients. The effects of fasting on these measurements were then compared. Results: The TAI and TSI measurements obtained from the upper and middle depths exhibited stronger correlations with the CAP measurements than those obtained from the lower depth. Specifically, the mean TAI had a significant positive correlation with MRI-PDFF (r = 0.753, P < 0.0001). TAI and TSI measurements exhibited excellent intra- (0.933 and 0.925, respectively) and inter- (0.896 and 0.766, respectively) examiner reliability. However, the correlation between HRI and CAP measurements was only 0.281, with no significant correlation with MRI-PDFF, and intra- and inter-examiner reproducibility of 0.458 and 0.343, respectively. Fasting did not affect these measurements. Conclusions: TAI and TSI measurements demonstrated good intra- and interobserver reliability and correlated well with CAP and MRI-PDFF measurements. However, in practice-based clinical applications, the sampling depth should be controlled within 2-4 cm of the hepatic capsule; no fasting is required before the examination.
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Magnetic reconnection, the rearrangement of magnetic field topologies, is a fundamental plasma process throughout the universe, which converts magnetic energy to plasma kinetic energy and results in particle energization. A current sheet is a prerequisite for the occurrence of magnetic reconnection. It has been well documented that reconnecting current sheets are prevalent in turbulent plasmas. However, how these current sheets are formed remains unclear. Among natural plasmas, the region downstream of the Earth's bow shock, the magnetosheath, is one of the most turbulent. Here, we show that the reconnecting current sheets in the turbulent magnetosheath originate from the waves in the region upstream of the shock. Once excited, the upstream waves are transmitted across the shock, compressed, and then transformed into current sheets in the downstream region. Magnetic reconnection subsequently occurs in these downstream current sheets. This process can be generalized to various shocked plasmas in astrophysical and laboratorial environments where turbulent magnetic reconnection should be common.
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Background: The novel echocardiographic parameter of myocardial work incorporates left ventricular pressure into the assessment of left ventricular systolic function and thereby corrects for afterload. We sought to investigate the diagnostic value of myocardial work to identify different grades of stenosis severity in coronary heart disease (CHD) patients with preserved left ventricular ejection fraction and without regional wall motion abnormalities. Methods: One hundred and seventeen consecutive subjects with preserved ejection fraction referred for coronary angiography were randomized and prospectively included in this study. Forty-six in the control group, and 25, 24, and 22 in each of the grade-1, grade-2, and grade-3 CHD groups as classified by the Gensini score. The following indices of myocardial work were assessed with a Vivid E95 Version 203 instrument: global work index (GWI), global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE). Results: Both GWI (P<0.001) and GCW (P<0.001) decreased significantly in CHD grade-1, increased slightly in CHD grade-2 compared with CHD grade-1, and decreased significantly in CHD grade-3. GWW (P<0.001) increased significantly from CHD grade-1 to CHD grade-3, while GWE (P<0.001) decreased significantly from CHD grade-1 to CHD grade-3. Receiver operating characteristic curves analysis revealed good discrimination between the control group and CHD grade-3 for GWI [area under the curve (AUC): 0.810; 95% confidence interval (CI): 0.691-0.930], GCW (AUC: 0.758; 95% CI: 0.631-0.885), GWW (AUC: 0.754; 95% CI: 0.624-0.885) and GWE (AUC: 0.817; 95% CI: 0.709-0.926). The assessment of intraobserver and interobserver variability in the MW echocardiographic data documented good interclass correlation coefficients (all >0.85). Conclusions: Myocardial work incorporates left ventricular pressure into the assessment of left ventricular systolic function and thereby corrects for afterload. It identifies patients with incipient left ventricular dysfunction caused by chronic ischemia due to CHD. A gradual worsening of myocardial work parameters was observed when comparing patients with higher degrees of stenosis severity. Therefore, adding myocardial work when evaluating patients with suspected CHD may help increase diagnostic accuracy.
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BACKGROUND: Viral pneumonia has always been a problem faced by clinicians because of its insidious onset, strong infectivity, and lack of effective drugs. Patients with advanced age or underlying diseases may experience more severe symptoms and are prone to severe ventilation dysfunction. Reducing pulmonary inflammation and improving clinical symptoms is the focus of current treatment. Low-intensity pulsed ultrasound (LIPUS) can mitigate inflammation and inhibit edema formation. We aimed to investigate the efficacy of therapeutic LIPUS in improving lung inflammation in hospitalized patients with viral pneumonia. METHODS: Sixty eligible participants with clinically confirmed viral pneumonia will be assigned to either (1) intervention group (LIPUS stimulus), (2) control group (null stimulus), or (3) self-control group (LIPUS stimulated areas versus non-stimulated areas). The primary outcome will be the difference in the extent of absorption and dissipation of lung inflammation on computed tomography. Secondary outcomes include changes in lung inflammation on ultrasonography images, pulmonary function, blood gas analysis, fingertip arterial oxygen saturation, serum inflammatory factor levels, the sputum excretion volume, time to the disappearance of pulmonary rales, pneumonia status score, and course of pneumonia. Adverse events will be recorded. DISCUSSION: This study is the first clinical study of the efficacy of therapeutic LIPUS in the treatment of viral pneumonia. Given that the current clinical recovery mainly depends on the body's self-limiting and conventional symptomatic treatment, LIPUS, as a new therapy method, might be a major advance in the treatment of viral pneumonia. TRIAL REGISTRATION: ChiCTR2200059550 Chinese Clinical Trial Registry, May 3, 2022.
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COVID-19 , Pneumonia Viral , Humanos , SARS-CoV-2 , Pneumonia Viral/tratamento farmacológico , Inflamação , Ondas Ultrassônicas , Resultado do Tratamento , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
Background: Cardiovascular disease (CVD) is widely observed in modern society. CVDs are responsible for the majority of fatalities, with heart attacks and strokes accounting for approximately 80% of these cases. Furthermore, a significant proportion of these deaths, precisely one-third, occurs in individuals under 70. Metabolic syndrome encompasses a range of diseases characterized by various physiological dysfunctions. These include increased inflammation in adipose tissue, enhanced cholesterol synthesis in the liver, impaired insulin secretion, insulin resistance, compromised vascular tone and integrity, endothelial dysfunction, and atheroma formation. These factors contribute to the development of metabolic disorders and significantly increase the likelihood of experiencing cardiovascular complications.Method: We selected studies that proposed hypotheses regarding metabolic disease syndrome and cardiovascular disease (CVD) and the role of Nrf2/HO-1 and factor regulation in CVD research investigations based on our searches of Medline and PubMed.Results: A total of 118 articles were included in the review, 16 of which exclusively addressed hypotheses about the role of Nrf2 on Glucose regulation, while 16 involved Cholesterol regulation. Likewise, 14 references were used to prove the importance of mitochondria on Nrf2. Multiple studies have provided evidence suggesting the involvement of Nrf2/HO-1 in various physiological processes, including metabolism and immune response. A total of 48 research articles and reviews have been used to highlight the role of metabolic syndrome and CVD.Conclusion: This review provides an overview of the literature on Nrf2/HO-1 and its role in metabolic disease syndrome and CVD.
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Doenças Cardiovasculares , Doenças Metabólicas , Síndrome Metabólica , Humanos , Síndrome Metabólica/complicações , Heme Oxigenase-1/metabolismo , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , ColesterolRESUMO
Niclosamide is a drug used to treat parasitic infections. Recent studies have shown that niclosamide may have a wide range of clinical applications and can be used to treat cancer and other diseases. However, its application is also limited by its water solubility and safety, and drug resistance to cancer. To solve these problems, some studies have shown that niclosamide can be used in combination with chemotherapeutic drugs, targeted drugs, radiotherapy, and immunotherapy to enhance the anti-tumor effect. This review summarizes the drug combination strategies and therapeutic effect of niclosamide, to provide a reference for the combination therapy of niclosamide and wider application of antitumor drugs.
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Antineoplásicos , Neoplasias , Humanos , Niclosamida/farmacologia , Niclosamida/uso terapêutico , Neoplasias/tratamento farmacológico , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Sistemas de Liberação de Medicamentos , ÁguaRESUMO
OBJECTIVE: The objective of this study was to describe the different components of left atrial (LA) dysfunction predictors in nonobstructive and occult obstructive hypertrophy cardiomyopathy (HCM) patients especially with preserved left ventricular (LV) ejection fraction, particularly using LA 4-dimensional (D) longitudinal and circumferential strains. METHODS: Twenty-eight nonobstructive HCM patients and 30 occult obstructive HCM patients according to LV outflow tract gradient at rest and after exercise were prospectively enrolled. 4D echocardiographic evaluation was performed in 58 HCM patients, both nonobstructive and occult obstructive, and 38 control subjects. LA reservoir, conduit, contractile functions were performed by 4D volume-strain with volumes and longitudinal, circumferential strains. RESULTS: Optimal correlation coefficients obtained between LV 4D mass (index) and LA 4D longitudinal/circumferential strain (r=-0.860 to 0.518, all P<0.001). Both nonobstructive and occult obstructive HCM patients had increased volumes and significantly decreased longitudinal, circumferential strain values with lower reservoir, conduit, contractile functions than the controls (all P<0.001). Occult obstructive HCM patients presented incremented volumes compared with nonobstructive ones (P<0.001 to 0.003). Lower conduit function and higher contractile function indicated with lower reservoir function revealed by circumferential strain in occult obstructive HCM patients than nonobstructive ones (P<0.001 to 0.017). Interclass correlation coefficients of intraobserver and interobserver in the LV and LA 4D value evaluations were >0.75 and >0.85, respectively. CONCLUSIONS: LA volumes were significantly increased and LA reservoir, conduit, and contractile functions were significantly impaired in HCM patients. Furthermore, different performances of LA functional analyses in nonobstruction and occult obstruction patients with 4D volume-strain echocardiography may facilitate the recognition of subtle LA dysfunctional differentiation in HCM patients.
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Cardiomiopatia Hipertrófica , Cardiomiopatia Hipertrófica/complicações , Cardiomiopatia Hipertrófica/diagnóstico por imagem , Átrios do Coração/diagnóstico por imagem , Humanos , Função Ventricular EsquerdaRESUMO
OBJECTIVE: Noninvasive measurement of myocardial work (MW) incorporates left ventricular (LV) pressure, and, therefore, allows correction of global longitudinal strain for changing afterload conditions. We sought to investigate MW as a tool to detect early signs of LV dysfunction in primary systemic hypertension patients, particularly with different predictive indices. METHODS AND RESULTS: None left ventricular hypertrophy (NLVH) and left ventricular hypertrophy (LVH) patients established were all primary systemic hypertension with preserved ejection fraction. Forty in NLVH and forty in LVH according to left ventricular end-diastolic mass index (LVEDmassI) were prospectively enrolled. The following indices of MW were assessed: global work index, global constructive work, global wasted work (GWW), and global work efficiency (GWE). Both global work index (P=0.348) and global constructive work (P=0.225) were increased in NLVH and decreased in LVH, and GWW (P<0.001) was increased significantly in NLVH and increased more in LVH, while GWE (P<0.001) was decreased significantly in NLVH and decreased more in LVH. The clinical utility of GWW (95% CI: 0.802-0.951) and GWE (95% CI: 0.811-0.950) were verified by receiver-operating characteristic curve analysis showing larger net benefits as evaluated with LVH and control comparisons. In multivariate linear regression analysis, 4-dimenaional LVEDmassI was independently associated with GWE (P=0.018) in systemic hypertension patients. Assessment of intraobserver and interobserver variability in the MW echocardiographic data documented good interclass correlation coefficients (all >0.85). CONCLUSION: GWW and GWE derived from MW are more accurate, sensitive, and reproducible predictors to detect early LV dysfunction in primary systemic hypertension patients, especially in distinguishing the potential functional abnormality of NLVH and LVH, even though the ejection fraction is preserved.
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By the introduction of the -tBu groups into aza-BODIPY core, di-tert-butyl-substituted aza-BODIPYs at 3,5-sites (tBuazaBDPs) were prepared for the first time. Based on the X-ray analysis of CN-tBuazaBDP, this molecular structure is twisted. Near-infrared dye SMe-tBuazaBDP has the ultra-large Stokes shift (152 ânm) in aza-BODIPY system, combining with the twisted intramolecular charge transfer and the free rotation of the -tBu groups at 3,5-sites. Although the barrier-free rotors of the distal -tBu groups in SMe-tBuazaBDP result in low fluorescence quantum yield, the photothermal conversion efficiency is markedly enhanced. SMe-tBuazaBDP nanoparticles with low power laser irradiation were proven to block cancer cell cycle, inhibit cancer cell proliferation, and induce cancer cell apoptosis in photothermal therapy (PTT). The strategy of "direct attachment of -tBu groups to aza-BODIPY core" gives a new design platform for a photothermal therapy agent.
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Breaking through the traditional 1,7,3,5-aryl substituted aza-BODIPY structure, asymmetric aza-BODIPYs, tBu-azaBDPs, containing non-aryl group at 3-site were prepared for the first time. tBu-azaBDP exhibited a severely twisted configuration. tBu-azaBDPs had a near-infrared fluorescence emission and high molar extinction coefficients. Although the barrier-free rotation of the distal -tBu group in tBu-azaBDP resulted in low fluorescence quantum yield, the photothermal conversion efficiency was markedly enhanced. tBu-azaBDP nanoparticles with laser irradiation were revealed to induce cell apoptosis in photothermal therapy. We consider that development of aza-BODIPYs with the barrier-free rotation of the -tBu group at 3-site provides a strong platform for design of phototherapy agents for cancer treatment in photothermal therapy by apoptosis.
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Neoplasias , Terapia Fototérmica , Apoptose , Compostos de Boro/química , Neoplasias/tratamento farmacológicoRESUMO
Due to high potency and low toxicity, desflurane has been widely used during surgery. Recent evidence that the use of desflurane was associated with colorectal cancer (CRC) tumor metastasis and poor prognosis raising concerns about the safety of desflurane. However, the mechanism was uncovered. CRC cells were exposed to desflurane, the changes in morphology and epithelial-mesenchymal transition (EMT)-related genes were evaluated. Transwell assay was used to study the migration and invasion effect. Xenograft was performed to study the tumor formation ability of desflurane-treated cells in vivo. Dual-luciferase reporter assay was conducted to verify the target of microRNA (miR)-34a. Knockdown or overexpression of LOXL3 was used to investigate the mechanism of desflurane-induced EMT. The association of LOXL3 with CRC molecular subtypes and clinical relevance was studied by analysis of public datasets. Exposure to desflurane induced EMT, migration, and invasion in CRC cells. Mice injected with desflurane-treated cells formed more tumors in the lungs. Downregulation of miR-34a and upregulation of LOXL3 were required for desflurane-induced EMT in CRC cells. LOXL3 was a direct target of miR-34a. Overexpression of LOXL3 rescued miR-34a-repressed EMT after exposure to desflurane. Elevated expression of LOXL3 was enriched in CMS4 and CRIS-B subtypes. Patients with high expression of LOXL3 showed more lymph node metastasis, as well as poor survival. Desflurane induced EMT and metastasis in CRC through deregulation of miR-34a/LOXL3 axis. Clinical miR-34a mimic or inhibitor targeting LOXL3 might have a potential protective role when patients with CRC anesthetized by desflurane.
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Anestesia , Neoplasias Colorretais , MicroRNAs , Aminoácido Oxirredutases/genética , Aminoácido Oxirredutases/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Desflurano , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismoRESUMO
The integration of segmentation and direct quantification on the left ventricle (LV) from the paired apical views(i.e., apical 4-chamber and 2-chamber together) echo sequence clinically achieves the comprehensive cardiac assessment: multiview segmentation for anatomical morphology, and multidimensional quantification for contractile function. Direct quantification of LV, i.e., to automatically quantify multiple LV indices directly from the image via task-aware feature representation and regression, avoids accumulative error from the inter-step target. This integration sequentially makes a stereoscopical reflection of cardiac activity jointly from the paired orthogonal cross views sequences, overcoming limited observation with a single plane. We propose a K-shaped Unified Network (K-Net), the first end-to-end framework to simultaneously segment LV from apical 4-chamber and 2-chamber views, and directly quantify LV from major- and minor-axis dimensions (1D), area (2D), and volume (3D), in sequence. It works via four components: 1) the K-Net architecture with the Attention Junction enables heterogeneous tasks learning of segmentation task of pixel-wise classification, and direct quantification task of image-wise regression, by interactively introducing the information from segmentation to jointly promote spatial attention map to guide quantification focusing on LV-related region, and transferring quantification feedback to make global constraint on segmentation; 2) the Bi-ResLSTMs distributed in K-Net layer-by-layer hierarchically extract spatial-temporal information in echo sequence, with bidirectional recurrent and short-cut connection to model spatial-temporal information among all frames; 3) the Information Valve tailing the Bi-ResLSTMs selectively exchanges information among multiple views, by stimulating complementary information and suppressing redundant information to make the efficient cross-flow for each view; 4) the Evolution Loss comprehensively guides sequential data learning, with static constraint for frame values, and dynamic constraint for inter-frame value changes. The experiments show that our K-Net gains high performance with a Dice coefficient up to 91.44% and a mean absolute error of the major-axis dimension down to 2.74mm, which reveal its clinical potential.
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Ventrículos do Coração , Coração , Ventrículos do Coração/diagnóstico por imagemRESUMO
A novel sulfide-based denitrification and Anammox process was established for simultaneous removal of nitrogen and sulfide in a UBF reactor. The effects of the N/S ratio on reactor performance were investigated under five N/S molar ratios (4.56, 2.38, 0.96, 0.73, and 0.51). The best total nitrogen removal efficiency was 82.8% at a N/S ratio of 2.38. When the N/S ratio exceeded 0.96, Anammox contributed to more than 90% of the N loss. Sulfide was completely removed during the full operational period and S0 accumulation occurred when N/S ratio was less than 1. Thiobacillus (6.1%) and Candidatus Kuenenia (18.8%) were the main functional microorganisms when nitrate was in excess on day 12. As nitrate became limited on day 50, Thiobacillus (21.0%), Sulfurimonas (3.9%), and Candidatus Kuenenia (19.7%) became dominated. In this study, Candidatus Kuenenia was not inhibited by the sulfide.
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Microbiota , Thiobacillus , Reatores Biológicos , Desnitrificação , Nitrogênio , Oxirredução , SulfetosRESUMO
Two different mixed sludges (aerobic nitrifying sludge and ANAMMOX-denitrification sludge:R1, and anaerobic digestion flocculent sludge and ANAMMOX-denitrification sludge:R2), were used as inocula in two UBF reactors to enrich Anammox bacteria. Both kinds of mixed sludge set up the Anammox process successfully. It took 36 days for R1, while R2 required 53 days. Nitrogen removal rates of R1 and R2 were high during the whole operation. During the stable operation stage, the removal rates of NH4+-N, NO2--N, and TN were about 99.92%, 96.64%, and 81.87% for R1; and 97.54%, 94.91%, and 80.98% for R2. Illumina High-throughput Sequencing revealed Candidatus Kuenenia was in the top six taxa in the two reactors with 3.22% relative abundance in R1 and 2.35% in R2 after the successful start-up. Simulation results indicated that the Modified Stover-Kincannon model and the second-order model were appropriate models. It was deduced that the N-removal potential of R1 was a little greater than that of R2 after comparing the projected maximum substrate removal rate Umax of the two reactors.
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The effect of glucose on nitrogen removal and microbial communities in the anammox-denitrification systems was investigated. The optimal nitrogen removal could be achieved when the influent glucose concentration was 56.4mgL-1. The influent nitrite to ammonium ratio of 0.95-1.40 would not obviously affect the nitrogen removal due to the coexistence of anammox, denitrification and partial denitrification. The anammox activity was deteriorated with increasing glucose concentration. When the influent glucose concentration was increased to 374.9mgL-1, the average ammonium removal efficiency decreased from 97% to around 10% and anammox activity was seriously inhibited. The anammox activity quickly recovered with decreasing influent glucose and increasing influent nitrite. High-throughput sequencing analysis suggested that the predominant genus changed from Candidatus Kuenenia to Diaphorobacter with the addition of glucose and then changed to Hydrogenophaga with the decrease of glucose. It indicated that organics concentration had an effect on the microbial communities.
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Reatores Biológicos , Desnitrificação , Compostos de Amônio , Glucose , NitrogênioRESUMO
The performance of biogas generation and sludge degradation was studied under different zero-valent iron/activated carbon (ZVI/AC) ratios in detail in mesophilic anaerobic digestion of sludge. A good enhancement of methane production was obtained at the 10:1 ZVI/AC ratio, and the cumulative methane production was 132.1 mL/g VS, 37.6% higher than the blank. The methane content at the 10:1 ZVI/AC ratio reached 68.8%, which was higher than the blank (55.2%) and the sludge-added AC alone (59.6%). For sludge degradation, the removal efficiencies of total chemical oxygen demand (TCOD), proteins, and polysaccharides were all the highest at the 10:1 ZVI/AC ratio. The concentration of available phosphorus (AP) decreased after anaerobic digestion process. On the other hand, the concentrations of available nitrogen (AN) and available potassium (AK) increased after the anaerobic digestion process and showed a gradually decreasing trend with increasing ZVI/AC ratio. The concentrations of AN and AK were 2303.1-4200.3 and 274.7-388.3 mg/kg, showing a potential for land utilization.