[Two cases of acute methyl acetate poisoning].

This article analyzed the clinical data and on-site occupational health survey results of a patient with occupational acute methyl acetate poisoning in Zhejiang. Based on the pathways of methyl acetate poisoning and the characteristics of target organ damage, diagnosis and treatment experience were summarized, providing reference for the diagnosis and treatment of occupational acute methyl acetate poisoning and occupational health monitoring of methyl acetate.

[Clinical application and analysis of single-port laparoscopic and thoracoscopic McKeown esophagectomy for esophageal cancer].

Objective: To explore the application value of single-port laparoscopic and thoracoscopic McKeown esophagectomy for esophageal cancer. Methods: A retrospective study was conducted to collect clinical data of 34 patients with esophageal cancer who were admitted to the Department of Thoracic Surgery, the First Affiliated Hospital of Fujian Medical University, from August to November 2020. All of them, 24 males and 10 females aged from 43 to 75 with an average of (62±4) years, underwent single-port laparoscopic and thoracoscopic McKeown esophagectomy.In the thoracic part, esophageal separation and mediastinal lymph node dissection were performed with conventional 4-ports thoracoscopy in the left lateral-prone position. In the abdominal part, gastric separation and lymph node dissection were accomplished with single-port laparoscopic retrograde three-step gastric separation: firstly, the lesser omentum was dissociated, the left liver lobe was suspended with purse-string needle and thread, after that the left gastric blood vessel and lymph node was dissected; secondly, the esophageal hiatus was separated, and the gastric cardia was cut off; finally, the spleen and stomach ligaments were dissociated to complete these steps. The operation time,volume of intraoperative blood loss, time for out-of-bed activities, time of postoperative drainage tube removal,volume of thoracic drainage fluid, short-term postoperative commplications,the postoperative pathological diagnoses, the time of their discharge from hospital and results of follow-up were observed. Results: All patients underwent successfully single-port laparoscopic and thoracoscopic esophagectomy without any conversion to open surgery; the operative time of the patients was 194-285 (240±21)min, including 53-105(60±13)min for the thoracic part and 40-73(49±7)min for the abdominal part. The volume of intraoperative blood loss was 15-110(60±20) ml. The numbers of mediastinal lymph node dissected and abdominal lymph nodes harvested were 10-25(13±3), 6-16(9±3)respectively. The 34 patients resumed out-of-bed activities on the 2nd to 3rd day after the operation. The thoracic closed drainage tube and left cervical drainage were removed 2 days after the operation. The thoracic Abel drainage tube was removed 5 days after the operation. The total volume of postoperative thoracic drainage fluid was 100-500(300±100)ml. No obvious sign of anastomotic leakage, anastomotic stenosis, chylothorax or gastric emptying disorder was found after the operation. Eight cases were complicated with temporal hoarseness, and 4 patients with pneumonia which was cured by antibiotics. The mean postoperative hospital stay was 8 days(6, 8), and patients were discharged after they could take a routine semi-liquid diet. The postoperative pathological diagnoses of all patients were squamous cell carcinoma, and the postoperative pathological stage was T1-3N0-1M0. Thirty-four patients were followed up for 60 (40, 75) days after the operation. During the follow-up period, no complication or death occurred. In addition, neither recurrence nor metastasis was observed. Conclusion: Single-port laparoscopic and thoracoscopic McKeown esophagectomy for esophageal carcinoma is safe and feasible, with good short-term efficacy. Therefore we consider it an alternative minimally invasive surgery for esophageal cancer.

microRNA-29b mediates Th17/Treg imbalance in chronic obstructive pulmonary disease by targeting IL-22.

Chronic obstructive pulmonary disease (COPD) represents a chronic inflammatory disorder of the airways induced mainly by cigarette smoking. In the current study, cigarette smoke extract (CSE) was used to develop an in vitro COPD model using human bronchial epithelium (HBE) cells to expound the possible role of microRNA-29b (miR-29b) in COPD. Firstly, miR-29b and interleukin (IL)-22 expression was assessed in serum of 20 healthy non-smokers, 20 healthy smokers and 20 COPD patients as well as CSE-treated HBE cells. Then, miR-29b and IL-22 expression was altered to evaluate their functions in Th17/Treg ratio. miR-29b inhibited Th17/Treg ratio and levels of IL-22; whereas overexpression of IL-22 reversed these trends. Moreover, rescue experiments found that IL-22 neutralized the repressive effects of miR-29b on Th17/Treg ratio and inflammatory response. Finally, we found that miR-29b blocked the JAK/STAT3 pathway in CSE-treated HBE cells. These data highlighted that miR-29bs modulated Th17/Treg imbalance in CSE-induced experimental COPD through inhibition of IL-22-dependent JAK/STAT3 pathway.

[Application of SF-36 scale in the survey of quality of life of occupational disease patients].

Objective: To explore the application of the Short Form of Quality of Life (SF-36) scale in the investigation of quality of life of occupational disease patients. Methods: In May 2019, SF-36 scale was used to investigate the occupational disease patients diagnosed in Hangzhou. The reliability of the scale was evaluated by Cronbach's α coefficient, and the validity of the scale was evaluated by exploratory factor analysis. Results: The Cronbach's α coefficients of PF, RP, BP, GH, VT, SF, RE and MH were 0.937, 0.977, 0.870, 0.908, 0.815, 0.701, 0.967 and 0.863 respectively, and the half reliability coefficient α=0.905. The two factor statistics representing physiological and psychological aspects were 0.870, and the approximate chi square value was 1784.337 (P<0.01) . Compared with the national norm, the scores of each dimension of quality of life of occupational disease patients were significantly lower, and the differences were statistically significant (P<0.01) ; Compared with the scores of each dimension of quality of life of pneumoconiosis patients, the scores of PF, RP and GH of occupational disease patients were significantly higher, and the differences were statistically significant (P<0.05) . Conclusion: SF-36 scale has good reliability and validity in measuring the quality of life of patients with occupational diseases, which can be used to evaluate the quality of life of patients with occupational diseases.

[Study on mechanisms of interleukin-17A regulating the expressions of interleukin-1ß and interleukin-23 in mouse keratinocytes].

Objective: To investigate the mechanisms of interleukin-17A (IL-17A) regulating the expressions of IL-1ß and IL-23 in mouse keratinocytes (KCs). Methods: Primary KCs were isolated from the skin of 400 newborn male and female wild type C57BL/6 mice and cultured in 24-well plates with Roswell Park Memorial Institute 1640 medium containing fetal bovine serum in the volume fraction of 10% for the following experiments. (1) The cells were divided into phosphate buffer solution (PBS) control group and IL-17A stimulation group according to the random number table (the same grouping method below), which were cultured with 10 µL PBS or 10 µL IL-17A in the mass concentration of 100 ng/mL for 6 hours, respectively. The expression levels of IL-1ß and IL-23 mRNA in cells were detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-PCR), with 3 samples in each group. (2) The cells were divided into dimethyl sulfoxide (DMSO) control group, IL-17A+ DMSO group, IL-17A+ nuclear factor κB (NF-κB) inhibitor group, IL-17A+ signal transduction and activator of transcription 3 (STAT3) inhibitor group, IL-17A+ extracellular signal-regulated kinase 1 (ERK1) inhibitor group, IL-17A+ ERK2 inhibitor group, and IL-17A+ c-Jun N-terminal kinase (JNK) inhibitor group. The reagents were added to cells in corresponding groups respectively and cultured for 6 hours. The volume of each reagent was 10 µL, the mass concentration of IL-17A was 100 ng/mL, and the molarity concentrations of NF-κB, STAT3, ERK1, ERK2, JNK signal pathway inhibitors PDTC, S3I-201, SCH772984, SCH772984, SP600125 were 5 µmol/L, 100 µmol/L, 4 nmol/L, 1 nmol/L, and 10 µmol/L, respectively. The expression levels of IL-1ß mRNA and IL-23 mRNA in cells were detected by real-time fluorescence quantitative RT-PCR, with 3 samples in each group. (3) The cells were grouped and treated the same as those in experiment (1). The levels of NF-κB phosphorylation, STAT3 phosphorylation, ERK phosphorylation, and JNK phosphorylation were detected by Western blotting, with 3 samples in each group. Data were statistically analyzed with two-tailed Student t test, one-way analysis of variance, t test, and Bonferroni correction. Results: (1) After culture of 6 hours, compared with those in PBS control group, the expression levels of IL-1ß and IL-23 mRNA in cells in IL-17A stimulation group were significantly increased (t=13.46, 6.72, P<0.01). (2) After culture of 6 hours, the expression levels of IL-1ß and IL-23 mRNA in cells in DMSO control group, IL-17A+ DMSO group, IL-17A+ NF-κB inhibitor group, IL-17A+ STAT3 inhibitor group, IL-17A+ ERK1 inhibitor group, IL-17A+ ERK2 inhibitor group, and IL-17A+ JNK inhibitor group were 1.00±0.11, 4.01±0.32, 0.32±0.06, 1.76±0.43, 3.62±0.24, 3.80±0.43, 4.26±0.74 and 1.03±0.29, 4.08±0.34, 4.76±0.38, 4.70±0.21, 1.06±0.42, 0.92±0.21, 0.39±0.05, respectively. Compared with those in DMSO control group, the expression levels of IL-1ß and IL-23 mRNA in cells in IL-17A+ DMSO group were significantly increased (t=9.24, 12.60, P<0.01). Compared with that in IL-17A+ DMSO group, the expression level of IL-1ß mRNA was significantly decreased in cells in IL-17A+ NF-κB inhibitor group and IL-17A+ STAT3 inhibitor group (t=11.34, 6.91, P<0.01). Compared with that in IL-17A+ DMSO group, the expression level of IL-23 mRNA was significantly decreased in cells in IL-17A+ ERK1 inhibitor group, IL-17A+ ERK2 inhibitor group, and IL-17A+ JNK inhibitor group (t=12.44, 13.03, 15.21, P<0.01). (3) After culture of 6 hours, compared with those in PBS control group, the levels of NF-κB phosphorylation, STAT3 phosphorylation, ERK phosphorylation, and JNK phosphorylation in cells in IL-17A stimulation group were significantly increased. Conclusions: IL-17A promotes the transcription of IL-1ß in mouse KCs through the phosphorylation of NF-κB and STAT3 pathways and IL-23 through the phosphorylation of ERK and JNK pathways.

[Study on quality of life and influeming factors of occupational disease patients in hangzhou].

Objective: To investigate and analyze the quality of life of occupational patients in Hangzhou and its influencing factors, so as to improve their qol. Methods: From January 2007 to June 2018, patients with diagnosed occupational diseases in Hangzhou City were randomly sampled in October 2019. The patients＇basic condition and quality of life were investigated by self-made questionnaire and SF-36, a total of 303 valid questionnaires were collected and the influencing factors were analyzed by correlation analysis and multiple linear regression. Results: The scores of physiological function, physiological function, physical pain, general health status, energy, social function, emotional function and mental health of the patients with occupational diseases in Hangzhou were lower than those of the general population in China, the differences were statistically significant (P<0.01) . The main factors affecting the score of quality of life of occupational patients are the types of occupational diseases, the level of disability and the duration of illness, the condition of suffering from other diseases, age, educational level, whether they are entitled to Work Injury Insurance, economic income, medical security and social support, the difference was statistically significant (P<0.05) . Conclusion: The quality of life of the patients with occupational diseases in Hangzhou City is poor, and the corresponding measures should be established to improve the qulity of life.

[Investigation and analysis of quality of life of some pneumoconiosis patients in Hangzhou].

Objective: To understand the quality of life and influencing factors of patients with pneumoconiosis, and to provide a basis for formulating targeted improvement strategies to improve the quality of life. Methods: From April to December 2018, Questionnaire survey was conducted on patients with pneumoconiosis that diagnosed in Hangzhou Hospital for the Prevention and Treatment of Occupational Disease, using self-made questionnaire and SF-36.237 valid questionnaires were used to investigate the basic conditions, health services, social assistance and quality of life of patients, and analyze the influencing factors of quality of life. Results: Hangzhou city's some pneumoconiosis patients were mostly with monthly income <3000 yuan (72.6%, 172/237) ; more patients with medical expenses of 8000 to 25000 yuan per year (60.3%, 143/237) ; The proportion of patients receiving medical assistance and work-related injury insurance was low, at 2.1% (5/237) and 23.8% (54/227) respectively. The scores of Pneumoconiosis patients in PhysicalFunction (PF) , Role-Physical (RP) , Bodily Pain (BP) , General Health (GH) , Vitality (VT) , Social Function (SF) , Role-Emotional (RE) and Mental Health (MH) were lower than the national norm (P<0.05) . The scores from high to low were BP, SF, MH, PF, VT, RE, RP and GH. There were significant differences in the quality of life scores of pneumoconiosis patients with different ages, work types, education levels and monthly income (P<0.05) . Conclusion: The quality of life of some patients with pneumoconiosis in Hangzhou is lower than that of the general population. Age, work types, and monthly income are factors influencing quality of life.

Determination of Endosulfan Concentrations in Biological Samples by GC-MS/MS.

OBJECTIVES: To establish an analytical method of the endosulfan concentrations （α-endosulfan and ß-endosulfan） in biological samples by GC-MS/MS. To observe the distribution of endosulfan in aquatic animals and provide experimental evidence for forensic identification of relevant cases. METHODS: Acetonitrile was added to the blood and muscle samples for precipitating the protein. The endosulfan concentrations were determined by GC-MS/MS in multiple reaction monitoring mode. Qualitative analysis was performed according to the retention time and ion rate, and quantitative analysis was performed by external standard working curve method. RESULTS: In blood samples, the calibration curves of α-endosulfan and ß-endosulfan ranging from 0.062 5 to 10 µg/mL had good linear relationship, the correlation coefficients （r） of which were >0.99. The limits of detection （LOD） were 1 ng/mL and 2 ng/mL and the limits of quantification （LOQ） were 4 ng/mL and 8 ng/mL, respectively. In muscle samples, the calibration curves of α-endosulfan and ß-endosulfan ranging from 0.062 5 to 10 µg/g, the r of which were >0.98. The LOD were 1 ng/g and 4 ng/g and the LOQ were 4 ng/g and 16 ng/g, respectively. The accuracy of α-endosulfan and ß-endosulfan was 90.76%-108.91% both in blood and muscle samples, the interday and intraday precision were 2.35%-8.71% and 5.44%-10.29%, respectively. In poisoning cases, endosulfan were detected in all parts of fish and crab and the content difference was statistically significant. CONCLUSIONS: The endosulfan detection method based on GC-MS/MS established in the present study is rapid, sensitive and accurate, which can be applied to the endosulfan detection in traces biological samples. The distribution of endosulfan in fish and crab was different, which can provide evidence to the sample collection and analysis for toxicological analysis in relevant forensic identification.

[Interaction of DAXX and human papillomavirus type 16 E2 protein].

The aim of the study was to explore the interactions of human papilloma virus 16 (HPV16) E2 protein and Daxx. The location or co-localization of PML and E2 with Daxx in Caski cells was observed by indirect immunofluorescence test. The interaction of E2 and Daxx was analyzed by co-immunoprecipitation, Western-blot and yeast-two hybrid assay. In Caski cells the fluorescence of Daxx or PML was mainly distributed in the cytoplasm or nucleus, respectively, and in the align image their signals did not overlapped. However, when the red signal of HPV16 E2 and the green signal of Daxx in cyto- plasm of Caski cells were merged, the yellow signals appeared. The yeast co-transformed with pGBKT7/Daxx and pGADT7/E2 or pGADT7/E2 TAD can grow onto SD/-Trp-Leu-His and SD/-Trp-Leu-His-Ade plates. So Daxx wasn't co-located with PML but with HPV16 E2 mainly in the cytoplasm of Caski cells. On the base of the results one can propose that HPV16 E2, in particularly its transcription-activity domain (TAD), interacts with Daxx.

Mosaic SCN1A mutations in familial partial epilepsy with antecedent febrile seizures.

SCN1A is the most relevant epilepsy gene. Mutations of SCN1A generate phenotypes ranging from the extremely severe form of Dravet syndrome (DS) to a mild form of generalized epilepsy with febrile seizures plus (GEFS+). Mosaic SCN1A mutations have been identified in rare familial DS. It is suspected that mosaic mutations of SCN1A may cause other types of familial epilepsies with febrile seizures (FS), which are more common clinically. Thus, we screened SCN1A mutations in 13 families with partial epilepsy with antecedent febrile seizures (PEFS+) using denaturing high-performance liquid chromatography and sequencing. The level of mosaicism was further quantified by pyrosequencing. Two missense SCN1A mutations with mosaic origin were identified in two unrelated families, accounting for 15.4% (2/13) of the PEFS+ families tested. One of the mosaic carriers with ~25.0% mutation of c.5768A>G/p.Q1923R had experienced simple FS; another with ~12.5% mutation of c.4847T>C/p.I1616T was asymptomatic. Their heterozygous children had PEFS+. Recurrent transmission occurred in both families, as noted in most of the families with germline mosaicism reported previously. The two mosaic mutations identified in this study are less destructive missense, compared with the more destructive truncating and splice-site mutations identified in the majority of previous studies. This is the first report of mosaic SCN1A mutations in families with probands that do not exhibit DS, but manifest only a milder phenotype. Therefore, such families with mild cases should be approached with caution in genetic counseling and the possibility of mosaicism origin associated with high recurrence risk should be excluded.

Correlation between local vibrations and metal mass in AlB2-type transition-metal diborides.

Lattice vibrations have been investigated in TiB2, ZrB2 and HfB2 by temperature-dependent extended X-ray absorption fine structure (EXAFS) experiments. Data clearly show that the EXAFS oscillations are characterized by an anomalous behavior of the Debye-Waller factor of the transition-metal-boron pair, which is suggested to be associated with a superposition of an optical mode corresponding to phonon vibrations induced by the B sublattice and an acoustic mode corresponding to the transition-metal (TM) sublattice. Data can be interpreted as a decoupling of the metal and boron vibrations observed in these transition-metal diborides (TMB2), a mechanism that may be responsible for the significant reduction of the superconducting transition temperature observed in these systems with respect to the parent MgB2 compound. The vibrational behavior of TM-TM bonds has also been investigated to study the occurrence of anisotropy and anomalies in the lattice vibrational behavior of TM-TM bonds.

Dynamic distribution of bone marrow-derived mesenchymal stromal cells and change of pathology after infusing into mdx mice.

BACKGROUND: Mesenchymal stromal cells (MSC) are attractive candidates for the treatment of Duchenne muscular dystrophy (DMD) but how the donor MSC distribute in multiple organs and whether the increased dystrophin leads to a change in the pathology of mdx mice is still uncertain. In this research we detected the distribution of MSC and the pathology of mdx mice after MSC infusion. METHODS: MSC were isolated from rat bone marrow (BM) and expanded in proliferation medium. MSC of the fifth passage were delivered intravenously into irradiated mdx mice. The distribution of MSC labeled by [3H]TdR into a recipient's organs was calculated by radioactivity. The expression of dystrophin was detected at weeks 4, 8, 12 and 16 after MSC transplantation by immunofluorescence staining, RT-PCR and Western blot. Serum creatine kinase (CK) and centrally nucleated fiber (CNF) were also detected to assess the change in pathology. RESULTS: 24-48 h after transplantation, MSC were mainly found in the BM, liver and lung. The radioactivity in these organs decreased, whereas skeletal and myocardial muscle radioactivity increased gradually over time. In accordance with the increased radioactivity in skeletal muscle, the amount of dystrophin-positive myofibers increased. Furthermore, serum CK and CNF decreased slightly, suggesting specific pathophysiologic features of the dystrophic muscle were partially restored. DISCUSSION: Upon certification of the distribution of transplanted MSC in irradiated mdx mice, we found evidence of myogenic differentiation of MSC in skeletal muscle. This research may help us understand the mechanism of therapy of MSC transplantation.

Activated beta-catenin induces myogenesis and inhibits adipogenesis in BM-derived mesenchymal stromal cells.

BACKGROUND: Mesenchymal stromal cells (MSC) have been thought to be attractive candidates for the treatment of degenerative muscle diseases. However, little is known about the molecular mechanisms governing the myogenic differentiation in MSC. As the Wnt signaling pathway has been associated with myogenesis in embryogenesis and post-natal muscle regeneration, we hypothesized that the Wnt signaling pathway may be involved in governing the myogenic differentiation in MSC. METHODS: Primary MSC were isolated from Sprague-Dawley rats and expanded in proliferation medium. The rMSC were transfected with a constitutively active hbeta-catenin (S37A) plasmid or control vector by Lipofectamine followed by G418 selection. The transfected rMSC were grown to 80% confluence and then cultured in myogenic or adipogenic differentiation medium. Cells were characterized by light microscopy, immunofluorescence and RT-PCR at different time points after myogenic or adipogenic introduction. RESULTS: Ectopic expression of activated beta-catenin located primarily in the nucleus and activated transcription in rMSC. Overexpression of stabilized beta-catenin induced 27.1 +/- 3.91% rMSC forming long multinucleated cells expressing MyoD, myogenin, desmin and myosin heavy chain (MHC) via evoking the expression of skeletal muscle-specific transcription factors. In addition, overexpression of activated beta-catenin inhibited the adipogenic differentiation in rMSC through down-regulated expressions of C/EBPalpha and PPARgamma. DISCUSSION: To our knowledge, this is the first evidence that activated beta-catenin can induce myogenic differentiation in rMSC. The ability of stabilized beta-catenin to induce myogenic differentiation in rMSC may allow for its therapeutic application.

Human mesenchymal stromal cells ameliorate the phenotype of SOD1-G93A ALS mice.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a progressive, lethal, neurodegenerative disease, currently without any effective therapy. Multiple advantages make mesenchymal stromal cells (MSC) a good candidate for cellular therapy in many intractable diseases such as stroke and brain injury. Until now, no irrefutable evidence exists regarding the outcome of MSC transplantation in the mouse model of ALS. The present study was designed to investigate the therapeutic potential of human MSC (hMSC) in the mouse model of ALS (SOD1-G93A mice). METHODS: hMSC were isolated from iliac crest aspirates from healthy donors and kept in cell cultures. hMSC of the fifth passage were delivered intravenously into irradiated pre-symptomatic SOD1-G93A mice. Therapeutic effects were analyzed by survival analysis, rotarod test, motor neuron count in spinal cord and electrophysiology. The engraftment and in vivo differentiation of hMSC were examined in the brain and spinal cord of hMSC-transplanted mice. RESULTS: After intravenous injection into irradiated pre-symptomatic SOD1-G93A mice, hMSC survived more than 20 weeks in recipient mice, migrated into the parenchyma of brain and spinal cord and showed neuroglia differentiation. Moreover, hMSC-transplanted mice showed significantly delayed disease onset (14 days), increased lifespan (18 days) and delayed disease progression compared with untreated mice. DISCUSSION: Our data document the positive effects of hMSC transplantation in the mouse model of ALS. It may signify the potential use of hMSC in treatment of ALS.

Advanced treatment for taste and odour control in drinking water: case study of a pilot scale plant in Seoul, Korea.

Taste and odour problems of tap water in Seoul are attributed to 2-methylisoborneol (2-MIB) and trans-1,10-dimethyl-trans-9-decalol (geosmin), which are the result of metabolism of algae and chlorine for disinfection. This study was carried out to measure 2-MIB and geosmin in the raw water from the Han River, to investigate removal efficiency of GAC and BAC integrated with post-ozonation, and to minimise and quantify the required chlorine concentration as a final disinfectant through the candidate process.

Electrocoagulation combined with the use of an intermittently aerating bioreactor to enhance phosphorus removal.

Biological Oxygen Demand (BOD), nitrogen, and phosphorus were treated with the use of an intermittently aerating bioreactor combined with electrocoagulation. Experiments consisting of batch reactor tests were conducted to identify the most efficient electrode material and the best condition for electrolysis so that the current density would not impede the biological treatment. The operating conditions needed when using an intermittently aerating bioreactor combined with electrocoagulation to enhance phosphorus removal were also identified. Iron was found to be more efficient than aluminum as an electrode material in terms of electricity requirement. When electrocoagulation was conducted and an intermittently aerating bioreactor was used, the electrolysis of the iron electrode in the aerobic stage was observed to be more favorable compared to continuous electrolysis. Sludge rise occurred at the current density of 5.7 mA cm(-2), and lysis of cell at 11.2 mA cm(-2). The applicable current density was found to be less than 4 mA cm(-2). Based on the results of this study, it can be concluded that the use of an intermittently aerating bioreactor combined with electrocoagulation enhances phosphorus removal in sewage treatment plants.

Characterization of humic substances isolated from Han River water and change in the structural and chemical characteristics by ozonation.

This study investigated the characteristics of extracted humic substances, which are ubiquitous in river waters and affect the treatment of water. Humic substances were extracted from the Han River water and analyzed using the samples obtained before/after ozonation with various analytical items. Ozonation was conducted in a batch-type reactor, and ozone was dosed from 0 to 2.0 mg O3 mg(-1) humic substances. The humic fraction was 56.0% of total organic carbon in the Han River and the ratio of fulvic to humic acids was approximately 3.46, including aromatic ring structures and/or various functional groups. Humic substances could not completely be oxidized to CO2, H2O, etc., but partly oxidized to low molecular weight matter, thus low removal efficiencies in terms of dissolved organic carbon (31% at 1.0 mg O3 mg(-1) humic substances) were observed. For UV absorbance at the wavelength 254 nm, ozone dose at 1.0 mg O3 mg(-1) humic substances showed more than 80% removal efficiencies. The molar ratios of H/C and O/C of the humic substances structure relatively increased by ozonation, indicating the degradation of aromatic groups in the humic substances molecule. The Fourier transform infrared spectra and proton nuclear magnetic resonance spectra of humic substances showed the increase in carboxylic acids and the decrease in aromatic protons through ozonation, respectively. As specific reaction sites in the humic substances including aromatic ring structures were reduced through ozone oxidation, contents of carboxylic acids, ketones and quinones in the humic substances molecule increased.

Evaluation of bipolar electrocoagulation applied to biofiltration for phosphorus removal.

To reduce the residual organic matter and phosphorus contained in secondary effluent, a biofiltration system combined with electrocoagulation using bipolar iron electrodes was evaluated as a supplementary treatment to existing small-community sewage treatment. Based on the results of batch tests, bipolar electrocoagulation (BEC) was found to be more effective on phosphorus removal than monopolar electrocoagulation (MEC) but energy consumption was less in monopolar electrocoagulation. Optimum conditions of BEC to treat the secondary effluent were current density 15 A/m2, electrode spacing 1 cm and pH < 8. The removals of COD(Cr) and phosphorus by biofiltration system without BEC were 69.1% and 9.6%, respectively. However, biofiltration system combined with BEC showed 76.6-83.7% and 70.7-93.0% removal for COD(Cr) and phosphorus respectively. Extraordinary increase in phosphorus could be achieved by introducing electrocoagulation to biofiltration, and BEC/biofiltration system was evaluated to be applicable to existing small-community sewage treatment plants as a supplementary process.

KNT-artificial neural network model for flux prediction of ultrafiltration membrane producing drinking water.

This paper describes the prediction of flux behavior in an ultrafiltration (UF) membrane system using a Kalman neuro training (KNT) network model. The experimental data was obtained from operating a pilot plant of hollow fiber UF membrane with groundwater for 7 months. The network was trained using operating conditions such as inlet pressure, filtration duration, and feed water quality parameters including turbidity, temperature and UV254. Pre-processing of raw data allowed the normalized input data to be used in sigmoid activation functions. A neural network architecture was structured by modifying the number of hidden layers, neurons and learning iterations. The structure of KNT-neural network with 3 layers and 5 neurons allowed a good prediction of permeate flux by 0.997 of correlation coefficient during the learning phase. Also the validity of the designed model was evaluated with other experimental data not used during the training phase and nonlinear flux behavior was accurately estimated with 0.999 of correlation coefficient and a lower error of prediction in the testing phase. This good flux prediction can provide preliminary criteria in membrane design and set up the proper cleaning cycle in membrane operation. The KNT-artificial neural network is also expected to predict the variation of transmembrane pressure during filtration cycles and can be applied to automation and control of full scale treatment plants.

Treatment of taste and odor material by oxidation and adsorption.

Massive blooms of blue-green algae in reservoirs produce the musty-earthy taste and odor, which are caused by compounds such as 2-MIB and geosmin. 2-MIB and geosmin are rarely removed by conventional water treatment. Their presence in the drinking water, even at low levels (ng/L), can be detected and it creates consumer complaints. So those concentrations have to be controlled as low as possible in the drinking water. The removals by oxidation (O3, Cl2, ClO2) and adsorption (PAC, filter/adsorber) were studied at laboratory and pilot plant (50 m3/d) to select suitable 2-MIB and geosmin treatment processes. The following conclusions were derived from the study. Both of the threshold odor levels for 2-MIB and geosmin appeared to be 30 ng/L as a consequence of a lab test. For any given PAC dosage in a jar-test, removal efficiencies of 2-MIB and geosmin were increased in proportion to PAC dosage and were independent of their initial concentration in raw water for the tested PAC dosages. In comparison of geosmin with 2-MIB, the adsorption efficiency of geosmin by PAC was superior to that of 2-MIB. The required PAC dosages to control below the threshold odor level were 30 mg/L for geosmin and 50 mg/L for 2-MIB at 100 ng/L of initial concentration. Removal efficiencies of odor materials by Cl2, ClO2, and O3 were very weak under the limited dosage (1.5 mg/L), however increased ozone dosage (3.8 mg O3/L) showed high removal efficiency (84.8% for 2-MIB) at contact time 6.4 minutes. According to the initial concentrations of 2-MIB and geosmin, their removal efficiencies by filter/adsorber differed from 25.7% to 88.4%. For all those, however, remaining concentrations of target materials in finished waters were maintained below 30 ng/L. The longer run-time given for the filter/adsorber, the higher the effluent concentration generated. So it is necessary that the run-time of the filter/adsorber be decreased, when 2-MIB or geosmin occurs in raw water.