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1.
Br J Dermatol ; 177(3): 708-718, 2017 Sep.
Article in English | MEDLINE | ID: mdl-27878819

ABSTRACT

Vitiligo is a common depigmenting disorder with profound psychosocial impacts. Previous observational studies have suggested a link between vitiligo and psychiatric morbidity, such as depression. However, variability in study design makes it difficult to quantify accurately the relationship between vitiligo and depression. We aimed to investigate the underlying prevalence and risk of depression among patients with vitiligo. A comprehensive search of MEDLINE, Embase and the Cochrane Library was conducted. Cross-sectional, case-control or cohort studies that assessed the prevalence of depression among patients with vitiligo or the relationship between vitiligo and depression were included. DerSimonian and Laird random-effects models were utilized to calculate the pooled prevalence and relative risks. Publication bias was evaluated by funnel plots and Egger's tests. Twenty-five studies with 2708 cases of vitiligo were included. Based on diagnostic codes, the pooled prevalence of depression among patients with vitiligo was 0·253 [95% confidence interval (CI) 0·16-0·34; P < 0·001)]. Using self-reported questionnaires, the pooled prevalence of depressive symptoms was 0·336 (95% CI 0·25-0·42; P < 0·001). The pooled odds ratio of depression among patients with vitiligo was 5·05 vs. controls (95% CI 2·21-11·51; P < 0·001). Moderate-to-high heterogeneity was observed between the studies. Patients with vitiligo were significantly more likely to suffer from depression. Clinical depression or depressive symptoms can be prevalent, with the actual prevalence differing depending on screening instruments or, possibly, geographical regions. Clinicians should actively evaluate patients with vitiligo for signs/symptoms of depression and provide appropriate referrals to manage their psychiatric symptoms accordingly.


Subject(s)
Depressive Disorder/etiology , Vitiligo/psychology , Depressive Disorder/diagnosis , Depressive Disorder/epidemiology , Early Diagnosis , Epidemiologic Methods , Humans , Vitiligo/epidemiology
2.
Water Environ Res ; 89(3): 260-273, 2017 Mar 01.
Article in English | MEDLINE | ID: mdl-28236820

ABSTRACT

The goal of this study was to establish a modeling tool for river water quality with a direct linkage to the water quality index (WQI5) calculation and the river water quality model, the Water Quality Analysis Simulation Program (WASP), for pollutant transport modeling. The integrated WASP and WQI5 tool was field-tested to assess pollutant loadings and their impacts on river environment. Suspended solid (SS) and electric conductivity (EC) correlation equations and the WQI5 calculation tool were included in the water quality model and direct WQI5 calculation. The SS concentration, which was influenced by river flows, had crucial effects on river water quality and WQI5 values. EC value was controlled by dissolution of soil minerals, which was affected by the watershed drainage area and surface runoff. The integrated system could establish a direct correlation for river water quality, river flow, and WQI5.


Subject(s)
Environmental Monitoring , Models, Theoretical , Rivers , Water Pollution , Water Quality , Computer Simulation , Taiwan
4.
Clin Exp Dermatol ; 41(3): 260-6, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26643816

ABSTRACT

BACKGROUND: Psoriasis has been reported to be associated with raised serum uric acid levels and gout, and uric acid has been demonstrated to mediate inflammatory pathways via secretion of pro-inflammatory chemokines. AIM: To evaluate the association between psoriasis, serum uric acid levels and gout in a cross-sectional study using the US National Health and Nutrition Examination Survey (NHANES) database. METHODS: Data on clinical history of psoriasis, gout and other relevant medical conditions from the questionnaire as well as laboratory parameters for serum uric acid and lipid levels in the periods 2003-2006 and 2011-2012 were analysed. Multivariate analysis with logistic regression modelling was performed, with hyperuricaemia as the dependent variable, and age, sex, ethnicity, body mass index, metabolic syndrome, current smoking status, alcohol consumption and history of psoriasis as the independent variables. RESULTS: Of the 11 282 study participants, 297 (2.6%) reported a history of psoriasis and 1493 (13.2%) were found to have hyperuricaemia. Patients with psoriasis were at increased risk of having hyperuricaemia, compared with those without psoriasis (OR = 1.37; P = 0.04). They were also more likely to report a history of gout (OR = 1.83; P < 0.05). However, neither association was significant after adjusting for potential confounders with multivariate logistic regression. CONCLUSION: In conclusion, there was insufficient evidence to show that psoriasis is an independent risk factor of hyperuricaemia or gout. A raised serum uric acid level may be a consequence of metabolic syndrome, which in turn is associated with psoriasis.


Subject(s)
Hyperuricemia/blood , Psoriasis/blood , Uric Acid/blood , Adult , Case-Control Studies , Cross-Sectional Studies , Female , Gout/blood , Humans , Hyperuricemia/etiology , Logistic Models , Male , Metabolic Syndrome/blood , Middle Aged , Psoriasis/complications , Risk Factors
5.
J Eur Acad Dermatol Venereol ; 30(12): 2007-2015, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27599898

ABSTRACT

Bullous pemphigoid (BP) is a chronic, autoimmune vesiculobullous disease that frequently occurs in the elderly population. Previous epidemiological studies have suggested an association between BP and neurological diseases; some studies, however, showed conflicting results. This study aimed to investigate if patients with BP have significantly higher risks for neurological disorders, compared to controls. A comprehensive search was performed using MEDLINE, EMBASE and Cochrane library databases. Case-control and cohort studies that assessed the relationship between BP and neurological diseases were included. DerSimonian and Laird random-effects models were utilized to calculate the pooled relative risks (RRs). Publication bias was evaluated qualitatively by constructing a funnel plot and quantitatively by conducting Egger's test. Fourteen studies, with 23 369 BP cases and 128 697 controls were included in this meta-analysis. Patients with BP were significantly more likely to have stroke (RR 2.68, 95% CI: 2.07-3.46), Parkinson's disease (PD; RR 3.42, 95% CI: 3.01-3.87), dementia (RR 4.46, 95% CI: 3.23-6.16), epilepsy (RR 2.98, 95% CI: 1.42-6.28), multiple sclerosis (RR 12.40, 95% CI: 6.64-23.17) and any aforementioned neurological disease (RR 4.93, 95% CI: 3.62-6.70), compared to controls. Moderate to high heterogeneity were observed for analyses of most neurological diseases, except for PD and multiple sclerosis. This study provided support for a significant association between BP and neurological diseases. Clinicians should be aware of this association and manage modifiable risk factors for neurological diseases accordingly.


Subject(s)
Nervous System Diseases/complications , Aged , Humans , Pemphigoid, Bullous/complications
6.
Arch Gerontol Geriatr ; 126: 105519, 2024 Jun 09.
Article in English | MEDLINE | ID: mdl-38941947

ABSTRACT

OBJECTIVE: To determine country/region-specific mortality (in-hospital, 30-day and 1-year) following hip fracture across the Asia Pacific region. METHODS: Five databases MEDLINE, PUBMED, EMBASE, Web of Science and the Cochrane Library were searched to identify studies that reported mortality following hospitalisation for low-trauma hip fracture in adults aged ≥50 years with data from 2010 to 30 September 2021. There were no restrictions on study design or language. Pooled mortality estimates for countries/regions with ≥2 studies were calculated using random-effects models. RESULTS: In total 244 studies were included in the meta-analysis. 123 studies (1,382,810 patients, 13 countries/regions) reported in-hospital mortality which ranged from 1.4 % in Japan [95 %CI 1.2-1.7], Singapore [95 %CI 1.0-1.6], China [95 %CI 0.8-2.3] and Hong Kong SAR [95 %CI 0.8-2.6] to 5.5 % [95 %CI 4.1-7.2] in New Zealand. 92 studies (628,450 patients, 13 countries/regions) reported 30-day mortality which ranged from 1.2 % in Japan [95 %CI 0.9-1.5] and Thailand [95 %CI 0.7-2.0] to 7.4 % [95 %CI 7.0-7.8] in Australia. 142 studies (1,139,752 patients, 14 countries/regions) reported 1-year mortality which ranged from 10.8 % [95 %CI 9.6-12.1] in Singapore to 23.3 % [95 %CI 22.3-24.5] in Australia and 23.8 % in New Zealand. CONCLUSION: There is substantial variation in mortality across the Asia Pacific region. Short-term mortality rates in Asian countries, notably Japan and Singapore, are up to four-fold lower than for Australia and New Zealand. This difference, although less marked, is sustained at 1-year with a two-fold lower mortality rate in Asia. This meta-analysis is the first to delineate these differences, further studies are required to understand the reasons for this variation.

7.
Diabet Med ; 30(3): 318-25, 2013 Mar.
Article in English | MEDLINE | ID: mdl-22946586

ABSTRACT

AIMS: To evaluate whether homeostasis model assessment and high-sensitivity C-reactive protein improve the prediction of isolated post-load hyperglycaemia. METHODS: The subjects were 1458 adults without self-reported diabetes recruited between 2006 and 2010. Isolated post-load hyperglycaemia was defined as fasting plasma glucose < 7 mmol/l and 2-h post-load plasma glucose ≥ 11.1 mmol/l. Risk scores of isolated post-load hyperglycaemia were constructed by multivariate logistic regression. An independent group (n = 154) was enrolled from 2010 to 2011 to validate the models' performance. RESULTS: One hundred and twenty-three subjects (8.28%) were newly diagnosed as having diabetes mellitus. Among those with undiagnosed diabetes, 64 subjects (52%) had isolated post-load hyperglycaemia. Subjects with isolated post-load hyperglycaemia were older, more centrally obese and had higher blood pressure, HbA(1c), fasting plasma glucose, triglycerides, LDL cholesterol, high-sensitivity C-reactive protein and homeostasis model assessment of insulin resistance and lower homeostasis model assessment of ß-cell function than those without diabetes. The risk scores included age, gender, BMI, homeostasis model assessment, high-sensitivity C-reactive protein and HbA(1c). The full model had high sensitivity (84%) and specificity (87%) and area under the receiver operating characteristic curve (0.91), with a cut-off point of 23.81; validation in an independent data set showed 88% sensitivity, 77% specificity and an area under curve of 0.89. CONCLUSIONS: Over half of those with undiagnosed diabetes had isolated post-load hyperglycaemia. Homeostasis model assessment and high-sensitivity C-reactive protein are useful to identify subjects with isolated post-load hyperglycaemia, with improved performance over fasting plasma glucose or HbA(1c) alone.


Subject(s)
Blood Glucose/metabolism , C-Reactive Protein/metabolism , Homeostasis/physiology , Hyperglycemia/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Diabetes Mellitus, Type 2/diagnosis , Fasting/blood , Female , Glucose Tolerance Test/methods , Glycated Hemoglobin/metabolism , Humans , Male , Middle Aged , Models, Biological , Risk Assessment , Young Adult
9.
Int J Clin Pharmacol Ther ; 49(6): 403-8, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21612748

ABSTRACT

Neuroendocrine tumors (NETs) occur in the bronchopulmonary system. Extrapulmonary NETs are rare and are considered to ac count for 2.5 - 5% of all NETs, with more than 60% of these tumors occurring along the gastro intestinal tract, including primary NET of the gall bladder. Pri mary NETs of the gall bladder have been classified as carcinoid, neuroendocrine carcinoma or heterogeneous carcinoma. Currently, the main treatment of neuroendocrine car ci noma re mains surgery. The role of radiotherapy and chemotherapy is undefined be cause of the paucity of data. In advanced cases, chemotherapy has been prescribed with such effective agents as cisplatin, carboplatin, etoposide and paclitaxel. Here we re port a case of a 64-year-old Taiwanese male patient with neuroendocrine carcinoma of the gall bladder who received combined chemoradiotherapy (CCRT) with cisplatin, 5- fluorouracil and leucovorin (PFL) from June 2009 un til now, and whose disease is stable. CCRT with PFL may be a possible reg i men for high-grade neuroendocrine carcinoma of the gall bladder.


Subject(s)
Carcinoma, Neuroendocrine/therapy , Gallbladder Neoplasms/therapy , Carcinoma, Neuroendocrine/pathology , Combined Modality Therapy , Gallbladder Neoplasms/pathology , Humans , Male , Middle Aged
10.
Int J Clin Pharmacol Ther ; 49(7): 461-6, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21726497

ABSTRACT

Erlotinib, a kind of epidermal growth factor receptor tyrosine kinase inhibitor, is a target therapy and approved for the treatment of metastatic non-small cell lung cancer (NSCLC) and advanced pancreatic cancer. Among these EGFR-TKI agents, including gefitinib and erlotinib, the common dose-limiting toxicities are diarrhea, mucositis and skin rash (Acneform eruptions). In addition to the above adverse effects, infrequent but potentially fatal and lethal entity complications include acute interstitial lung disease (ILD) and acute hepatitis. The incidence of EGFR-TKI agents (gefitinib and erlotinib) induced acute hepatitis is rare and hepatotoxicity of EGFR-TKI agent was rarely discussed. The treatment of EGFR-TKI agents induced acute hepatitis remains uncertain and cessation medication is current policy. Here we reported a case of erlotinib induced interstitial pneumonitis and acute hepatitis with clinical appearance of hypoxemia and general weakness, treated with high dose pulse therapy and showed good recovery.


Subject(s)
Adrenal Cortex Hormones/therapeutic use , Anti-Inflammatory Agents/therapeutic use , Antineoplastic Agents/adverse effects , Chemical and Drug Induced Liver Injury/drug therapy , Lung Diseases, Interstitial/drug therapy , Quinazolines/adverse effects , Adenocarcinoma/complications , Adenocarcinoma/drug therapy , Aged , Alanine Transaminase/blood , Antineoplastic Agents/therapeutic use , Aspartate Aminotransferases/blood , Chemical and Drug Induced Liver Injury/diagnostic imaging , ErbB Receptors/antagonists & inhibitors , Erlotinib Hydrochloride , Humans , Liver Function Tests , Lung Diseases, Interstitial/chemically induced , Lung Diseases, Interstitial/diagnostic imaging , Lung Neoplasms/complications , Lung Neoplasms/drug therapy , Male , Methylprednisolone/therapeutic use , Muscle Weakness/chemically induced , Muscle Weakness/epidemiology , Quinazolines/therapeutic use , Radiography, Thoracic
11.
J Bacteriol ; 192(12): 3144-58, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20382770

ABSTRACT

Sequence analysis of the large virulence plasmid pLVPK in Klebsiella pneumoniae CG43 revealed the presence of another mucoid factor encoding gene rmpA besides rmpA2. Promoter activity measurement indicated that the deletion of rmpA reduced K2 capsular polysaccharide (CPS) biosynthesis, resulting in decreased colony mucoidy and virulence in mice. Introduction of a multicopy plasmid carrying rmpA restored CPS production in the rmpA or rmpA2 mutant but not in the rcsB mutant. Transformation of the rmpA deletion mutant with an rcsB-carrying plasmid also failed to enhance CPS production, suggesting that a cooperation of RmpA with RcsB is required for regulatory activity. This was further corroborated by the demonstration of in vivo interaction between RmpA and RcsB using two-hybrid analysis and coimmunoprecipitation analysis. A putative Fur binding box was only found at the 5' noncoding region of rmpA. The promoter activity analysis indicated that the deletion of fur increased the rmpA promoter activity. Using electrophoretic mobility shift assay, we further demonstrated that Fur exerts its regulatory activity by binding directly to the promoter. As a result, the fur deletion mutant exhibited an increase in colony mucoidy, CPS production, and virulence in mice. In summary, our results suggested that RmpA activates CPS biosynthesis in K. pneumoniae CG43 via an RcsB-dependent manner. The expression of rmpA is regulated by the availability of iron and is negatively controlled by Fur.


Subject(s)
Bacterial Capsules/metabolism , Bacterial Proteins/metabolism , Gene Expression Regulation, Bacterial/physiology , Klebsiella pneumoniae/metabolism , Polysaccharides, Bacterial/biosynthesis , Animals , Bacterial Proteins/genetics , Cloning, Molecular , Culture Media/chemistry , Gene Expression Regulation, Bacterial/drug effects , Iron/chemistry , Iron/pharmacology , Klebsiella pneumoniae/classification , Mice , Mutation , Repressor Proteins/genetics , Repressor Proteins/metabolism , Transcription Initiation Site , Transcription, Genetic
12.
Eur J Clin Microbiol Infect Dis ; 29(6): 689-98, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20383552

ABSTRACT

Klebsiella pneumoniae-caused liver abscess (KLA) is an emerging infectious disease. However, factors other than K1-specific loci that contribute to the pathogenesis of this disease have not been identified. pLVPK is a 219,385-bp plasmid of K. pneumoniae CG43, an invasive K2 strain associated with KLA. We aimed in this study to evaluate the involvement of pLVPK in K. pneumoniae virulence and its clinical significance in abscess formation. A pLVPK-cured CG43 was isolated and its virulence was examined in a mouse model. The prevalence of pLVPK-derived loci terW, iutA, rmpA, silS, and repA was investigated in 207 clinical isolates by screening with specific primers. Loss of pLVPK abolished the ability of K. pneumoniae to disseminate into extraintestinal sites and, consequently, attenuated abscess formation in mice. Primary K. pneumoniae abscess isolates (n = 94) were more likely to be terW (+)-iutA (+)-rmpA (+)-silS (+) than those related to non-abscess infections (n = 113) (62% vs. 27%; p < 0.0001). Logistic regression analysis indicated that the presence of the terW-rmpA-iutA-silS loci was a significant risk factor (odds ratio, 4.12; 95% confidence interval, 2.02-8.4; p < 0.0001) for abscess formation. pLVPK is a determinant for K. pneumoniae virulence and infection with strains carrying the pLVPK-derived terW-rmpA-iutA-silS loci may predispose patients to abscess formation.


Subject(s)
Bacterial Proteins/genetics , Klebsiella Infections/microbiology , Klebsiella pneumoniae/genetics , Klebsiella pneumoniae/pathogenicity , Liver Abscess/microbiology , Plasmids/analysis , Virulence Factors/genetics , Animals , Disease Models, Animal , Female , Humans , Klebsiella pneumoniae/isolation & purification , Male , Mice , Middle Aged , Sequence Deletion
13.
Int J Clin Pharmacol Ther ; 48(7): 425-8, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20557834

ABSTRACT

We report a case of acute interstitial pneumonitis and respiratory failure occurring in a 69-year-old, previously healthy patient receiving FOLFOX regimen plus cetuximab for colon cancer. Association between this chemotherapy regimen and interstitial pneumonitis is rarely reported in the literature. We treated the patient with pulse steroid therapy, and improvement in respiratory function and decreased pulmonary infiltrations demonstrated good response to steroids use. However, the patient ultimately expired from respiratory complications after 98 days from admission, possibly due to secondary infection. Both oxaliplatin and cetuximab have rarely been associated with interstitial pneumonitis, and our case may serve as an important reference for physicians notice in patients receiving these chemotherapeutic agents.


Subject(s)
Adenocarcinoma/drug therapy , Antibodies, Monoclonal/adverse effects , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Colonic Neoplasms/drug therapy , Lung Diseases, Interstitial/chemically induced , Acute Disease , Aged , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal, Humanized , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Cetuximab , Female , Fluorouracil/administration & dosage , Fluorouracil/adverse effects , Humans , Leucovorin/administration & dosage , Leucovorin/adverse effects , Organoplatinum Compounds/administration & dosage , Organoplatinum Compounds/adverse effects
14.
Water Environ Res ; 82(11): 2205-18, 2010 Nov.
Article in English | MEDLINE | ID: mdl-21141382

ABSTRACT

Kaoping River Basin is the largest and most intensively used river basin in Taiwan. In this study, 14 types of land-use patterns in the basin are classified with the aid of the Erdas Imagine process (Erdas, Inc., Atlanta, Georgia) and ArcView geographic information system (GIS) (ESRI, Redlands, California). Results from GIS identification and field verification indicate that orchard gardens, rice paddies, and sugarcane fields dominate the farmland areas in the basin. Investigation results indicate that nonpoint-source (NPS) pollution has significant contributions to the suspended solids load to the Kaoping River during the wet season. The average suspended solids concentrations increased from below 64 mg/ L in dry seasons to more than 1700 mg/L in wet seasons. The Integrated Watershed Management Model (Systech Engineering, Inc., San Ramon, California) was applied to simulate the water quality and evaluate the NPS suspended solids load to the river. Modeling results show that forestation and land-use management are feasible best management practices for NPS suspended solids reduction.


Subject(s)
Rivers , Sanitary Engineering , Water Pollutants , Water Pollution/prevention & control , Environmental Monitoring , Models, Theoretical , Rain , Soil , Taiwan , Time Factors
15.
Water Sci Technol ; 61(10): 2549-55, 2010.
Article in English | MEDLINE | ID: mdl-20453327

ABSTRACT

The Kaoping River Rail Bridge Constructed Wetland, which was commissioned in 2004, is one of the largest constructed wetlands in Taiwan. This multi-function wetland has been designed for the purposes of non-point source (NPS) pollutant removal, wastewater treatment, wildlife habitat, recreation, and education. The major influents of this wetland came from the local drainage trench containing domestic, agricultural, and industrial wastewaters, and effluents from the wastewater treatment plant of a paper mill. Based on the quarterly investigation results from 2007 to 2009, more than 96% of total coliforms (TC), 48% of biochemical oxygen demand (BOD), and 40% of nutrients (e.g. total nitrogen, total phosphorus) were removed via the constructed wetland system. Thus, the wetland system has a significant effect on water quality improvement and is capable of removing most of the pollutants from the local drainage system before they are discharged into the downgradient water body. Other accomplishments of this constructed wetland system include the following: providing more green areas along the riversides, offering more water assessable eco-ponds and eco-gardens for the public, and rehabilitating the natural ecosystem. The Kaoping River Rail Bridge Constructed Wetland has become one of the most successful multi-function constructed wetlands in Taiwan. The experience obtained from this study will be helpful in designing similar natural treatment systems for river water quality improvement and wastewater treatment.


Subject(s)
Fresh Water , Rivers , Water Pollutants/isolation & purification , Water Pollution/prevention & control , Water/standards , Wetlands , Ecosystem , Enterobacteriaceae/isolation & purification , Nitrogen/isolation & purification , Oxygen/isolation & purification , Phosphorus/isolation & purification , Taiwan , Water Microbiology
16.
Water Sci Technol ; 62(7): 1667-75, 2010.
Article in English | MEDLINE | ID: mdl-20935386

ABSTRACT

The Houjing River watershed is one of the three major river watersheds in the Kaohsiung City, Taiwan. Based on the recent water quality analysis, the Houjing River is heavily polluted. Both point and non-point source (NPS) pollutants are the major causes of the poor water quality in the Houjing River. Investigation results demonstrate that the main point pollution sources included municipal, agricultural, and industrial wastewaters. In this study, land use identification in the Houjing River watershed was performed by integrating the skills of geographic information system (GIS) and global positioning system (GPS). Results show that the major land-use patterns in the upper catchment of the Houjing River watershed were farmlands, and land-use patterns in the mid to lower catchment were residential and industrial areas. An integrated watershed management model (IWMM) and Enhanced Stream Water Quality Model (QUAL2K) were applied for the hydrology and water quality modeling, watershed management, and carrying capacity calculation. Modeling results show that the calculated NH3-N carrying capacity of the Houjing River was only 31 kg/day. Thus, more than 10,518 kg/day of NH3-N needs to be reduced to meet the proposed water quality standard (0.3 mg/L). To improve the river water quality, the following remedial strategies have been developed to minimize the impacts of NPS and point source pollution on the river water quality: (1) application of BMPs [e.g. source (fertilizer) reduction, construction of grassy buffer zone, and land use management] for NPS pollution control; (2) application of river management scenarios (e.g. construction of the intercepting and sewer systems) for point source pollution control; (3) institutional control (enforcement of the industrial wastewater discharge standards), and (4) application of on-site wastewater treatment systems for the polishment of treated wastewater for water reuse.


Subject(s)
Conservation of Natural Resources , Rivers/chemistry , Water Pollution/prevention & control , Environmental Restoration and Remediation , Geography , Humans , Models, Theoretical , Rivers/microbiology , Taiwan
17.
Sci Rep ; 10(1): 6153, 2020 Apr 09.
Article in English | MEDLINE | ID: mdl-32273552

ABSTRACT

Abundant earthquakes clustered within a particular zone often reflect an active geological feature, such as clustering seismicity along a fault zone and a huge number of volcanic-earthquakes around the erupting conduit. Herein we perform a double-difference tomographic inversion and relocate the seismicity at the long-resting Tatun volcano group (TVG) in northern Taiwan. A dramatic improvement of the earthquake location model surprisingly show that, from 2014 to 2017, two clustered seismic zones are identified in the TVG. One major group of events (>1000) persistently clustered within a ~500 m diameter vertical conduit with a ~2 km height. The clustering seismicity conduit is just located nearby Dayoukeng, one of the strongest fumaroles in the TVG, and is connected to a fracture zone characterized by low Vp/Vs in the shallow crust. The other group of events is clustered within a sphere-like zone beneath Mt. Chihsin around the depths between 0.5 km and 2 km. Both seismic zones are probably triggered by the significantly volcanic gases and fluids ascending from the deep magma reservoir. Combined with a variety of results from literature, the seismicity conduit near the strong fumarole is the evidence for an active volcano and also identifies a likely pathway for ascending magma if the TVG erupts again in the future. But possibility of developing different magma pathways at other clustered seismic zones such as beneath Mt. Chihsin may not be totally excluded.

18.
Environ Monit Assess ; 158(1-4): 319-31, 2009 Nov.
Article in English | MEDLINE | ID: mdl-18956245

ABSTRACT

In Taiwan, nonpoint source (NPS) pollution is one of the major causes of the impairment of surface waters. I-Liao Creek, located in southern Taiwan, flows approximately 90 km and drains toward the Kaoping River. Field investigation results indicate that NPS pollution from agricultural activities is one of the main water pollution sources in the I-Liao Creek Basin. Assessing the potential of NPS pollution to assist in the planning of best management practice (BMP) is significant for improving pollution prevention and control in the I-Liao Creek Basin. In this study, land use identification in the I-Liao Creek Basin was performed by properly integrating the skills of geographic information system (GIS) and global positioning system (GPS). In this analysis, 35 types of land use patterns in the watershed area of the basin are classified with the aid of Erdas Imagine process system and ArcView GIS system. Results indicate that betel palm farms, orchard farms, and tea gardens dominate the farmland areas in the basin, and are scattered around on both sides of the river corridor. An integrated watershed management model (IWMM) was applied for simulating the water quality and evaluating NPS pollutant loads to the I-Liao Creek. The model was calibrated and verified with collected water quality and soil data, and was used to investigate potential NPS pollution management plans. Simulated results indicate that NPS pollution has significant contributions to the nutrient loads to the I-Liao Creek during the wet season. Results also reveal that NPS pollution plays an important role in the deterioration of downstream water quality and caused significant increase in nutrient loads into the basin's water bodies. Simulated results show that source control, land use management, and grassy buffer strip are applicable and feasible BMPs for NPS nutrient loads reduction. GIS system is an important method for land use identification and waste load estimation in the basin. Linking the information of land utilization with the NPS pollution simulation model may further provide essential information of potential NPS pollution for all subregions in the river basin. Results and experience obtained from this study will be helpful in designing the watershed management and NPS pollution control strategies for other similar river basins.


Subject(s)
Environmental Monitoring/methods , Geographic Information Systems , Water Pollution/analysis , Rivers , Taiwan
19.
Sci Rep ; 9(1): 3223, 2019 Mar 01.
Article in English | MEDLINE | ID: mdl-30824718

ABSTRACT

We combined spectroscopic ellipsometry, Raman scattering spectroscopy, and first-principles calculations to explore the optical properties of YBaCuFeO5 single crystals. Measuring the optical absorption spectrum of YBaCuFeO5 at room temperature revealed a direct optical band gap at approximately 1.41 eV and five bands near 1.69, 2.47, 3.16, 4.26, and 5.54 eV. Based on first-principles calculations, the observed optical excitations were appropriately assigned. Analysis of the temperature dependence of the band gap indicated anomalies in antiferromagnetic phase transition at 455 and 175 K. Additionally, a hardening in the frequency of the Eg phonon mode was observed at 175 K. The value of the spin-phonon coupling constant was 15.7 mRy/Å2. These results suggest a complex nature of spin-charge-lattice interactions in YBaCuFeO5.

20.
Sci Rep ; 9(1): 18586, 2019 Dec 09.
Article in English | MEDLINE | ID: mdl-31819082

ABSTRACT

Temperature-dependent X-ray absorption near-edge structures, X-ray linear dichroism (XLD) and extended X-ray absorption fine structure (EXAFS) spectroscopic techniques were used to investigate the valence state, preferred orbital and local atomic structure that significantly affect the electrical and magnetic properties of a single crystal of YBaCuFeO5 (YBCFO). An onset of increase of resistivity at ~180 K, followed by a rapid increase at/below 125 K, is observed. An antiferromagnetic (AFM)-like transition is close to the temperature at which the resistivity starts to increase in the ab-plane and is also observed with strong anisotropy between the ab-plane and the c-axis. The XLD spectra at the Fe L3,2-edge revealed a change in Fe 3d eg holes from the preferential [Formula: see text] orbital at high temperature (300-150 K) to the [Formula: see text] orbital at/below 125 K. The analysis of the Fe K-edge EXAFS data of YBCFO further revealed an unusual increase in the Debye-Waller factor of the nearest-neighbor Fe-O bond length at/below 125 K, suggesting phonon-softening behavior, resulting in the breaking of lattice symmetry, particularly in the ab-plane of Fe-related square pyramids. These findings demonstrate a close correlation between electrical resistivity and coupling of the preferred Fe 3d orbital with lattice distortion of a single crystal of YBCFO.

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