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1.
Leuk Res ; 76: 87-93, 2019 01.
Article in English | MEDLINE | ID: mdl-30503643

ABSTRACT

To analyze the pattern of multiple mutations detected by Sanger sequencing (SS), we performed subcloning sequencing using 218 samples from 45 patients with tyrosine kinase inhibitor resistant chronic myeloid leukemia. At the first time of multiple mutation detection by SS (baseline), a total of 19 major mutations from 45 samples were detected; these mutations were found in the following order: T315I (68.9%), E255 K (33.3%), Y253H (13.3%), G250E (13.3%), and F317 L (11.1%). Subcloning sequencing of 900 baseline colonies identified 556 different mutant types, and 791 among the 900 were colonies with major mutations (87.9%). The mutations were found in the following order: T315I (36.4%), E255 K (16.2%), Y253H (7.0%), G250E (6.7%), M351 T (6.6%), and E255 V (5.3%). In subcloning sequencing with 4357 colonies of 218 serial samples, 2506 colonies (57.5%) had compound mutations, among which 2238 colonies (89.3%) had at least one major mutation. The median number of mutations in compound mutant colonies was 2 (range, 2-7), and most were double (52.9%) or triple (28.7%) mutations. Additionally, some mutations in allosteric binding sites were detected as low level mutation in 13 patients. With the available retrospective samples before baseline, subcloning sequencing identified low-level mutations of various frequencies (median, 10%) to be major mutations in 20 patients. Thus, compound mutations involving T315I and P-loop mutations were the major components of multiple mutations, and some low-level mutations with potential clinical significance were detected by subcloning sequencing. Hence, more sensitive sequencing assays are needed in patients with multiple mutations.


Subject(s)
Drug Resistance, Neoplasm/genetics , Fusion Proteins, bcr-abl/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Mutation , Protein Kinase Inhibitors/pharmacology , Adolescent , Adult , Aged , Alleles , Antineoplastic Agents/pharmacology , Cloning, Molecular , Female , Fusion Proteins, bcr-abl/chemistry , Gene Expression , Humans , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/diagnosis , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Male , Middle Aged , Young Adult
2.
Sci Rep ; 8(1): 13907, 2018 Sep 17.
Article in English | MEDLINE | ID: mdl-30224773

ABSTRACT

Non-magnetic (NM) metals with strong spin-orbit coupling have been recently explored as a probe of interface magnetism on ferromagnetic insulators (FMI) by means of the spin Hall magnetoresistance (SMR) effect. In NM/FMI heterostructures, increasing the spin mixing conductance (SMC) at the interface comes as an important step towards devices with maximized SMR. Here we report on the study of SMR in Pt/Fe3O4 bilayers at cryogenic temperature, and identify a strong dependence of the determined real part of the complex SMC on the interface roughness. We tune the roughness of the Pt/Fe3O4 interface by controlling the growth conditions of the Fe3O4 films, namely by varying the thickness, growth technique, and post-annealing processes. Field-dependent and angular-dependent magnetoresistance measurements sustain the clear observation of SMR. The determined real part of the complex SMC of the Pt/Fe3O4 bilayers ranges from 4.96 × 1014 Ω-1 m-2 to 7.16 × 1014 Ω-1 m-2 and increases with the roughness of the Fe3O4 underlayer. We demonstrate experimentally that the interface morphology, acting as an effective interlayer potential, leads to an enhancement of the spin mixing conductance.

3.
Cancer Med ; 7(10): 5107-5117, 2018 10.
Article in English | MEDLINE | ID: mdl-30171671

ABSTRACT

The present study aimed to assess the clinical impact of BCR-ABL1 transcript levels determined at an earlier time point than the 3-month early molecular response (EMR) in chronic-phase chronic myeloid leukemia (CML-CP) patients. BCR-ABL1 transcript levels of CML-CP patients (n = 258; median age, 43 [range, 18-81] years) treated with various tyrosine kinase inhibitors (TKIs) were determined at 4 weeks (28 ± 3 days) and at every 3 months of treatment initiation. At 4 weeks, receiver operating characteristic curves revealed that cutoff values of BCR-ABL1 transcripts for achieving major molecular responses (MMRs) by 12 and 60 months were 40.89% and 39.16%, respectively (95% CI, 0.658-0.772 and 95% CI, 0.643-0.758; P < 0.0001). With 40% of BCR-ABL1 transcripts at 4 weeks (very early MR; VEMR), patients with VEMR achieved higher 3-month EMR and 4-week VEMR significantly associated with higher cumulative incidences of 5-year MMR (89.1% vs 72.3%; P < 0.001) and 5-year deep molecular response (DMR) (56.5% vs 29.4%; P = 0.001). Furthermore, event-free survival (EFS)-a (93.0% vs 84.8%; P = 0.068) and EFS-b (71.1% vs 57.9%; P = 0.061) by 5 years were also marginally significant. VEMR and 3-month EMR were achieved in 89 patients, with significantly superior outcomes. In multivariate analyses, lower leukocyte count (P = 0.008) and frontline second-generation TKI therapy size (P < 0.001) were significantly associated with VEMR achievement, but not baseline BCR-ABL1 level and CML duration. In conclusion, the 4-week BCR-ABL1 transcript levels including VEMR could be important to predict long-term outcomes and may provide additional information about innate intrinsic sensitivity to CML among individuals.


Subject(s)
Fusion Proteins, bcr-abl/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Protein Kinase Inhibitors/administration & dosage , Adult , Aged , Aged, 80 and over , Female , Gene Expression Regulation, Neoplastic/drug effects , Humans , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Leukocyte Count , Male , Middle Aged , Prognosis , Protein Kinase Inhibitors/pharmacology , Survival Analysis , Treatment Outcome , Young Adult
4.
Leuk Lymphoma ; 59(1): 105-113, 2018 01.
Article in English | MEDLINE | ID: mdl-28540759

ABSTRACT

We conducted this study to identify the factors for predicting poor outcomes in chronic myeloid leukemia patients who failed to achieve a 3-month early molecular response (EMR). Of the 413 newly diagnosed, chronic phase, chronic myeloid leukemia patients receiving imatinib (IM), 120 (29.1%) failed to achieve a 3-month EMR. With a median follow-up of 67.0 months, 39 patients continued IM treatment with at least complete cytogenetic response (CCyR), and 81 patients permanently discontinued IM treatment. The cumulative incidence rates of CCyR and major molecular response (MMR) by 3 years were 90.1 ± 3.9% and 53.7 ± 7.3%, respectively. After adjusting for potential factors, multivariate analyses showed that a transcript type of e13a2, compared with e14a2, and a larger spleen size were independent factors for failure of overall MMR. The predictive factors outlined in this study may provide valuable information for high-risk patients who would benefit from early decision-making regarding therapy change.


Subject(s)
Fusion Proteins, bcr-abl/genetics , Leukemia, Myeloid, Chronic-Phase/genetics , Leukemia, Myeloid, Chronic-Phase/pathology , Splenomegaly , Transcription, Genetic , Adolescent , Adult , Aged , Antineoplastic Agents/therapeutic use , Female , Humans , Imatinib Mesylate/therapeutic use , Leukemia, Myeloid, Chronic-Phase/drug therapy , Leukemia, Myeloid, Chronic-Phase/mortality , Male , Middle Aged , Prognosis , Protein Kinase Inhibitors/therapeutic use , Time Factors , Treatment Failure , Treatment Outcome , Young Adult
5.
ACS Appl Mater Interfaces ; 9(19): 16063-16070, 2017 May 17.
Article in English | MEDLINE | ID: mdl-28443657

ABSTRACT

All-solid-state Li-rechargeable batteries using a 500 nm-thick LiCoO2 (LCO) film deposited on two NASICON-type solid electrolyte substrates, LICGC (OHARA Inc.) and Li1.3Al0.3Ti1.7(PO4)3 (LATP), are constructed. The postdeposition annealing temperature prior to the cell assembly is critical to produce a stable sharp LCO/electrolyte interface and to develop a strong crystallographic texture in the LCO film, conducive to migration of Li ions. Although the cells deliver a limited discharge capacity, the cells cycled stably for 50 cycles. The analysis of the LCO/electrolyte interfaces after cycling demonstrates that the sharp interface, once formed by proper thermal annealing, will remain stable without any evidence for contamination and with minimal intermixing of the constituent elements during cycling. Hence, although ionic conductivity of the NASICON-type solid electrolyte is lower than that of the sulfide electrolytes, the NACSICON-type electrolytes will maintain a stable interface in contact with a LCO cathode, which should be beneficial to improving the capacity retention as well as the rate capability of the all-solid state cell.

6.
Environ Technol ; 38(23): 3007-3015, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28110608

ABSTRACT

Due to its limited recycling or reuse, treatment and disposal of excess waste activated sludge has been a major challenge. As a preemptive method, therefore, uncoupling metabolism for reduced sludge production has been investigated recently. In this study, we operated a pilot-scale A2O-membrane bioreactor (MBR) system incorporating an anaerobic sludge holding tank (SHT) in a sludge recycling line to induce uncoupling metabolism, and investigated sludge production and treatment efficiency. After operation for ≥1 year, the Yobs value was estimated to be 0.041 g mixed liquor suspended solid (MLSS)/g chemical oxygen demand with 198.7 days of solids retention time (SRT). This Yobs value was markedly lower than those reported previously. Since MBR can be operated with a relatively high MLSS and prolonged SRT, the greatest reduction was achieved by combination with uncoupling metabolism. Phosphate fractionation experiments of the MLSS from the pilot MBR suggested the total phosphate content of microorganisms was 47.0 mg P/g mixed liquor volatile suspended solid; 83% higher than that of the activated sludge process and 49% higher than that of the conventional A2O process. Of the increased phosphate contents, that of the acid-insoluble polyphosphate (AISP) fraction was greatest, suggesting that growth inhibition by uncoupling metabolism stimulates AISP synthesis, which can be utilized under growth-limiting conditions. ABBREVIATIONS: AISP: acid-insoluble polyphosphate; ASP: acid-soluble polyphosphate; BNR: biological nutrients removal; EPS: extracellular polymeric substance; LMH: L/m2 h; MBR: membrane bioreactor; OST: oxic-settling-anaerobic; PAO: phosphate accumulation organism; PCA: perchloric acid; SBR: sequencing batch reactor; SHT: sludge holding tank; SRT: solids retention time; TN: total nitrogen; TP: total phosphate; WAS: waste activated sludge.


Subject(s)
Bioreactors , Waste Disposal, Fluid/methods , Biomass , Membranes, Artificial , Phosphorus/metabolism
7.
Korean J Intern Med ; 32(1): 125-136, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27334764

ABSTRACT

BACKGROUND/AIMS: The aim of this study was to identify the role of BCR-ABL1 transcript level as a predictor for post-transplant relapse and outcome in patients who underwent allogeneic stem cell transplantation (SCT) for chronic phase (CP) chronic myeloid leukemia (CML). METHODS: Of 101 patients receiving allograft in CML CP, 85 had available quantitative reverse transcriptase polymerase chain reaction data at post-transplant 3 months. These patients were divided into two groups according to molecular response (MR4.5), defined as a BCR-ABL1 transcript level ≤ 0.0032% on the international scale, at 3 months based on receiver operating characteristic curve analysis of relapse. RESULTS: The 4-year overall survival and event-free survival (EFS) were 80.6% and 57.3%, respectively, and the cumulative incidence of relapse at 4 years was 29.6% after a median follow-up of 126.4 months. We performed multivariate analyses including potential variables to evaluate the early predictive role of MR4.5 at 3 months and found that MR4.5 at 3 months was associated with a higher EFS (p = 0.028) and showed a trend for a lower relapse rate (p = 0.089). CONCLUSIONS: our results imply that frequent molecular monitoring and immune suppressive therapy modulation are required for patients without reduction of BCR-ABL1 transcripts to this level after SCT.


Subject(s)
Biomarkers, Tumor/genetics , Fusion Proteins, bcr-abl/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/surgery , Stem Cell Transplantation , Adolescent , Adult , Area Under Curve , Disease-Free Survival , Drug Therapy, Combination , Female , Graft vs Host Disease/etiology , Humans , Immunosuppressive Agents/therapeutic use , Kaplan-Meier Estimate , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/diagnosis , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism , Male , Middle Aged , Multivariate Analysis , Predictive Value of Tests , Proportional Hazards Models , ROC Curve , Recurrence , Reverse Transcriptase Polymerase Chain Reaction , Risk Factors , Stem Cell Transplantation/adverse effects , Stem Cell Transplantation/mortality , Time Factors , Transplantation, Homologous , Treatment Outcome , Young Adult
8.
Leuk Res ; 39(4): 411-8, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25680524

ABSTRACT

To explore the factors for achieving early molecular responses (EMR; BCR-ABL1 ≤10% at 3 months, ≤1% at 6 months) by imatinib (IM), baseline characteristics including individual BCR-ABL1 transcript level, dose intensity, and IM trough level on day 29 were analyzed in 286 chronic phase chronic myeloid leukemia patients. Distinct predictive factors for achieving EMR at 3 months and 6 months were noted. Blast count at diagnosis and IM trough level on day 29 were significantly associated with an achievement of 3-month EMR. Early decline of BCR-ABL1 transcript, low Sokal risk, and mean daily dose (≥350mg/day) by 6 months were associated with an achievement of 6-month EMR. Understanding the predictive factors for EMR may provide additional information to guide clinical decisions on the changing therapies at each landmark.


Subject(s)
Antineoplastic Agents/therapeutic use , Benzamides/therapeutic use , Biomarkers, Tumor/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Piperazines/therapeutic use , Pyrimidines/therapeutic use , Adolescent , Adult , Aged , Female , Follow-Up Studies , Fusion Proteins, bcr-abl/genetics , Humans , Imatinib Mesylate , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/mortality , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Male , Middle Aged , Neoplasm Staging , Prognosis , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Survival Rate , Time Factors , Young Adult
9.
Water Sci Technol ; 70(1): 82-8, 2014.
Article in English | MEDLINE | ID: mdl-25026583

ABSTRACT

Amongst sludge reduction strategies, the anaerobic side-stream sludge holding tank (SHT) is of particular interest because it has shown significant sludge reduction efficiency. However, due to the anaerobic and starving environment of the SHT, the release of extracellular polymeric substance (EPS) may be stimulated, and it may hamper the application of the SHT to the membrane bioreactor. In order to investigate the effect of sludge storage on EPS release, sludge samples from a pilot-scale sequencing batch reactor coupled with SHT was incubated in a series of bench-scale SHT reactors for different periods of time (0-24 h). The increase in EPS was not significant until 12 h of incubation (9.3%), while 40.9% of the increase was observed in the sample incubated for 24 h. The rapid increase in EPS concentration after 12 h indicates a greater rate of cell lysis than that with EPS consumption as substrate. Since inducing the initial stage of the endogenous phase within microorganisms is a key factor for the successful operation of the SHT for sludge reduction, the retention time for the SHT should be shorter than the time for the sudden increase in EPS release.


Subject(s)
Bioreactors , Sewage/chemistry , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/analysis , Water Purification/methods , Anaerobiosis , Equipment Design , Filtration , Membranes, Artificial , Microscopy, Electron, Scanning , Polymers/analysis , Time Factors , Waste Disposal, Fluid/instrumentation , Water Purification/instrumentation
10.
Water Sci Technol ; 67(12): 2838-44, 2013.
Article in English | MEDLINE | ID: mdl-23787326

ABSTRACT

By evaluating microbial kinetic parameters of a pilot sludge blanket reactor (SBR) plant operated with an anaerobic sludge holding tank (SHT), it was found that the sludge production was reduced by 63.5%. According to the theory of uncoupling metabolism, the microorganisms were induced to the initial stage of the endogenous phase in SHT, which resulted in the reduction of yield coefficient. For the determination of optimal retention time in SHT without causing a significant decay of microorganisms, ammonia concentration was monitored with time at specific temperature and mixed liquor suspended solids concentrations. In a long-term (>1 yr) operation of the pilot plant, no deterioration of the effluent water quality was observed. Considering phosphorus removal, an extended sludge retention time of 60-70 days (due to the reduced yield coefficient) did not significantly affect the efficiency relative to typical biological nutrient removal (BNR) processes. According to the findings of this study, anaerobic SHT can be applied for BNR processes with reduced production of sludge, and this will help to minimize environmental and economic problems pertaining to the final disposal of sludge.


Subject(s)
Bioreactors , Sewage/chemistry , Anaerobiosis , Kinetics , Pilot Projects , Waste Disposal, Fluid/methods
11.
J Knee Surg ; 22(3): 267-9, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19634733

ABSTRACT

Localized pigmented villonodular synovitis involving the posterior intra-articular structures of the knee joint is rare. We report a case of localized pigmented villonodular synovitis arising from the posterior capsule of the knee joint in a patient who presented with a history of repeated joint effusions and loss of terminal knee flexion. After successful, complete removal of the mass through the posteromedial portal, the patient was asymptomatic, with no evidence of recurrence during the 26-month follow-up period.


Subject(s)
Joint Capsule/surgery , Knee Joint/surgery , Synovitis, Pigmented Villonodular/diagnosis , Synovitis, Pigmented Villonodular/surgery , Adult , Arthralgia/physiopathology , Arthralgia/surgery , Arthroscopy , Humans , Joint Capsule/pathology , Knee Joint/physiopathology , Magnetic Resonance Imaging , Male , Range of Motion, Articular/physiology
12.
J Hazard Mater ; 165(1-3): 540-7, 2009 Jun 15.
Article in English | MEDLINE | ID: mdl-19026488

ABSTRACT

In this study, the transformation of 1-naphthol via oxidative-coupling reaction was investigated using Mn oxides. 1-Naphthol was transformed completely by birnessite, which is one of the natural Mn oxides present in soil. The surface area-normalized specific rate constant, k(surf), for 1-naphthol was determined to be 9.66 x 10(-4)L/m(2)min using observed pseudo-first-order rate constants with respect to birnessite loading. The transformation of 1-naphthol was dependent on the solution pH, and the pseudo-first-order rate constants increased from 0.028 at pH 11 to 0.075 at pH 2 at a birnessite loading of 0.625 g/L. GC and LC mass spectroscopic analysis of the supernatants were performed after separating the reaction solution into hydrophobic and hydrophilic fractions by solvent extraction. The major transformation products were found to be 1,4-naphthoquinone(1,4-NPQ) and naphthol polymerized products with a molecular weight (m/z) ranging from 400 to 2000. Transformation of 1,4-NPQ, to the polymerized products by an additional birnessite loading was also verified. The DOC concentrations of the supernatants before and after the reaction were analyzed and the rate of oligomeric precipitate formation was measured.


Subject(s)
Manganese Compounds/chemistry , Naphthols/chemistry , Oxides/chemistry , Chemical Phenomena , Chemical Precipitation , Environmental Restoration and Remediation/methods , Kinetics , Oxidation-Reduction , Solutions
13.
Water Sci Technol ; 58(1): 171-8, 2008.
Article in English | MEDLINE | ID: mdl-18653951

ABSTRACT

In this study, removals of 1-naphthol by oxidative-coupling reaction using birnessite, one of the natural Mn oxides present in soil, was investigated in various experimental conditions (reaction time, Mn oxide loadings, pH). The removal efficiency of 1-naphthol by birnessite was high in all the experimental conditions, and UV-visible and mass spectrometric analyses on the supernatant after reaction confirmed that the reaction products were oligomers formed by oxidative-coupling reaction. Pseudo-first order rate constants, k, for the oxidative transformation of 1-naphthol by birnessite was derived from the kinetic experiments under various amounts of birnessite loadings, and using the observed pseudo-first order rate constants with respect to birnessite loadings, the surface area normalised specific rate constant, k(surf), was also determined to be 9.3 x 10(-4) (L/m(2).min) for 1-naphthol. In addition, the oxidative transformation of 1-naphthol was found to be dependent on solution pH, and the pseudo-first order rate constants were increased from 0.129 at pH 10 to 0.187 at pH 4.


Subject(s)
Manganese Compounds , Oxides , Polycyclic Aromatic Hydrocarbons/isolation & purification , Chromatography, High Pressure Liquid , Chromatography, Liquid , Indicators and Reagents , Kinetics , Mass Spectrometry , Naphthols , Oxidation-Reduction , Spectroscopy, Fourier Transform Infrared , Surface Properties , Water Purification/methods
14.
Knee ; 15(4): 325-9, 2008 Aug.
Article in English | MEDLINE | ID: mdl-18434161

ABSTRACT

Ganglion cysts of the posterior cruciate ligament (PCL) are uncommon lesions found incidentally on MRI and arthroscopy. Twenty patients (11 males and nine females) with the mean age of 35 years presenting with a variety of knee signs and symptoms were found to have PCL cysts on MRI. Out of these, thirteen patients (65%) had isolated symptomatic PCL cysts and seven patients had associated chondral and meniscal lesions. Eight out of the 20 patients (40%) gave a history of antecedent trauma. On arthroscopy, the majority of the cysts were situated at the midsubstance of the ligament with inter-cruciate distension and no involvement of the substance of the ligament. The content of the cysts varied with the majority having yellowish viscous fluid and three containing serous and bloody fluid. All cysts were successfully treated arthroscopically through standard anterior, posteromedial and posterolateral portals with no signs of recurrence on MRI at a mean followup of 24 months. PCL cysts may clinically mimic meniscal or chondral lesions and preoperatively, MRI is essential for the diagnosis of ganglion cysts arising from the PCL. Ganglion cysts of the PCL can be successfully treated arthroscopically using standard portals.


Subject(s)
Ganglion Cysts/diagnosis , Ganglion Cysts/surgery , Posterior Cruciate Ligament , Adolescent , Adult , Arthroscopy , Cohort Studies , Female , Ganglion Cysts/etiology , Humans , Male , Middle Aged , Range of Motion, Articular , Retrospective Studies , Treatment Outcome
15.
Environ Toxicol Chem ; 27(5): 1031-8, 2008 May.
Article in English | MEDLINE | ID: mdl-18419188

ABSTRACT

Phenanthrene and pyrene were not transformed by birnessite (delta-MnO2) in the presence of phenol. The phenoxy radicals generated from phenol by birnessite did not act as a mediator for polycyclic aromatic hydrocarbon radical reaction under the studied conditions. In contrast, 9-hydroxyphenanthrene and 1-hydroxypyrene were remarkably sensitive to birnessite. The disappearance patterns of the test compounds both in the aqueous phase and soil followed first-order kinetics, with a linear relationship found between the rate constants and the surface area of birnessite. Moreover, the data indicated that the reaction was faster in the presence of soil than in the aqueous phase probably because of the presence of hydroxyl groups in soil organic matter. Sequential solvent extraction was not successful in the recovery of 9-hydroxyphenanthrene from the birnessite-treated soil samples, and capillary electrophoresis data suggest the formation of nonextractable residues of the compound in soil. In addition, the acute toxicity determined by Microtox declined approximately 8.3 times in the soil samples treated with birnessite compared to untreated samples, demonstrating that the toxic compound was no longer present as its parent form.


Subject(s)
Oxides/chemistry , Polycyclic Compounds/chemistry , Soil Pollutants/chemistry , Hydroxylation , Kinetics , Oxides/toxicity , Polycyclic Compounds/toxicity , Soil Pollutants/toxicity
16.
Article in English | MEDLINE | ID: mdl-18205056

ABSTRACT

Oxidative coupling reaction of phenol mediated by birnessite was studied in aqueous phase and soil. Phenol was readily transformed by birnessite and almost all phenol disappeared in both samples after 24 hours of reaction. Phenol transformation kinetics was investigated by plotting reaction time against logarithm concentrations of residual phenol, revealing that exponential decrease of phenol was evident both in aqueous phase and soil, and maximum removal rates were 2.31-2.54 times higher in the presence of soil. Reaction products of phenol were identified by LC-MS and capillary electrophoresis. In aqueous phase, polyphenols were formed by self-coupling reaction of phenoxy radicals whereas phenol was found to be present as bound residues in soil, probably due to the cross-coupling reaction between the radicals and soil organic matter. Microtox System was employed to determine the toxicity after birnessite treatment, and the toxicity of phenol-spiked solution and soil samples decreased remarkably compared to that of phenol solution before treatment.


Subject(s)
Oxides/chemistry , Phenol , Soil Pollutants , Aliivibrio fischeri/drug effects , Environmental Restoration and Remediation , Kinetics , Oxidation-Reduction , Phenol/analysis , Phenol/toxicity , Soil Pollutants/analysis , Soil Pollutants/toxicity , Toxicity Tests
17.
Water Res ; 40(5): 903-10, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16490230

ABSTRACT

Abiotic transformation of TNT reduction products via oxidative-coupling reaction was investigated using Mn oxide. In batch experiments, all the reduction products tested were completely transformed by birnessite, one of natural Mn oxides present in soil. Oxidative-coupling was the major transformation pathway, as confirmed by mass spectrometric analysis. Using observed pseudo-first-order rate constants with respect to birnessite loadings, surface area-normalized specific rate constants, ksurf, were determined. As expected, ksurf of diaminonitrotoluenes (DATs) (1.49-1.91L/m2 d) are greater about 2 orders than that of dinitroaminotoluenes (DNTs) (1.15 x 10(-2)-2.09 x 10(-2)L/m2d) due to the increased number of amine group. In addition, by comparing the value of ksurf between DNTs or DATs, amine group on ortho position is likely to be more preferred for the oxidation by birnessite. Although cross-coupling of TNT in the presence of various mediator compounds was found not to be feasible, transformation of TNT by reduction using Fe0 followed by oxidative-coupling using Mn oxide was efficient, as evaluated by UV-visible spectrometry.


Subject(s)
Manganese Compounds/chemistry , Oxides/chemistry , Trinitrotoluene/chemistry , Iron/chemistry , Kinetics , Oxidation-Reduction , Soil Pollutants
18.
Korean J Intern Med ; 20(1): 68-71, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15906956

ABSTRACT

Swallowing is a rare cause of neurally mediated syncope. The mechanism of swallow syncope that contributes to hypotension, bradycardia, or to both is complex. A 59-year-old man had experienced a recurrent loss of consciousness during swallowing of carbonated beverages or sticky foods. Another 59-year-old man had complained of intermittent syncope just after eating foods. These two patients had no significant structural or functional abnormalities in the esophagus or heart. Both cases showed bradycardia when the lower esophagus was stretched by balloon inflation. The activation of mechanoreceptors in the lower esophagus can be regarded as an initiating factor of these cardioinhibitions. The patients were treated with permanent pacemaker implantation and instructed to change eating habits, respectively.


Subject(s)
Deglutition/physiology , Esophagus/innervation , Mechanoreceptors/physiology , Syncope/etiology , Bradycardia/etiology , Humans , Male , Middle Aged
19.
Water Res ; 38(11): 2737-45, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15207604

ABSTRACT

Naturally occurring phenols were evaluated as mediators for the transformation of the fungicide cyprodinil by birnessite. With birnessite alone, cyprodinil transformation was negligible (0.6%). In the presence of mediators, however, it increased considerably (1.5-60.9%). With some exceptions (2,6-dimethoxyphenol, syringic acid), methoxylated phenols showed a substantial capacity for enhancing the transformation. Mass spectrometry indicated that cyprodinil cross-coupled with free radicals of phenols formed at birnessite surfaces. The extent of cyprodinil transformation in the presence of syringaldehyde, m-methoxyphenol, or vanillin increased with the amount of birnessite. In reactions with o- and p-methoxyphenol and vanillic acid, cyprodinil transformation was unaffected by the amount of birnessite, but it increased with increasing phenol concentration. The addition of various humic acids at low concentrations (5-10 mg/L) had little effect on cyprodinil transformation in the presence of o-methoxyphenol or syringaldehyde. At higher concentrations, however, humic acids inhibited the transformation (by 5-20%) when o-methoxyphenol was a mediator, but showed no effect in the presence of syringaldehyde.


Subject(s)
Magnesium Oxide/chemistry , Pyrimidines/metabolism , Water Pollutants, Chemical/metabolism , Biotransformation , Humic Substances , Mass Spectrometry , Oxidation-Reduction , Temperature , Water/chemistry
20.
Water Res ; 36(19): 4907-15, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12448535

ABSTRACT

Xenobiotic chemicals can be transformed or covalently bound to humic materials by oxidoreductive enzymes present in terrestrial systems. Chemicals that are not substrates for oxidoreductive enzymes may undergo transformation in the presence of certain reactive compounds, which are often referred to as mediators. In this study, cyprodinil, a broad-spectrum fungicide, did not show any transformation when incubated alone with a laccase from Trametes villosa. It was transformed to a significant extent, however, when a mediator was present. All of the 13 tested mediators belonged to the group of naturally occurring phenols. With some exceptions (2,6-dimethoxyphenol, syringic acid, and ferulic acid), phenols substituted with one or two methoxy groups were very effective mediators. In experiments with 14C-labeled cyprodinil, the radioactive label was largely associated with brown transformation products that precipitated out of the aqueous solution. As determined by mass spectrometry, the products were mixed oligomers resulting from cross-coupling between cyprodinil and a mediator. The addition of large amounts of humic acid (HA) (400 mg/L) to the reaction mixtures involving the most effective mediators reduced cyprodinil transformation (42.6-68.6%) by 12-48%, probably due to an inhibitory effect. The inhibition decreased with decreasing concentration of HA. The addition of HA (400 mg/L) to the reaction mixtures involving the least effective mediators or no mediators (control) enhanced cyprodinil transformation (0.3-17.6%) by 2.9-17.1%, probably as a result of binding to HA.


Subject(s)
Basidiomycota/enzymology , Fungicides, Industrial/metabolism , Oxidoreductases/pharmacology , Pyrimidines/metabolism , Water Pollutants, Chemical/metabolism , Biotransformation , Humic Substances/chemistry , Laccase , Mass Spectrometry , Oxidation-Reduction , Phenols/chemistry
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