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1.
Nephrology (Carlton) ; 29(5): 245-258, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38462235

RESUMO

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited cause of end-stage kidney disease (ESKD) worldwide. Guidelines for the diagnosis and management of ADPKD in Taiwan remains unavailable. In this consensus statement, we summarize updated information on clinical features of international and domestic patients with ADPKD, followed by suggestions for optimal diagnosis and care in Taiwan. Specifically, counselling for at-risk minors and reproductive issues can be important, including ethical dilemmas surrounding prenatal diagnosis and pre-implantation genetic diagnosis. Studies reveal that ADPKD typically remains asymptomatic until the fourth decade of life, with symptoms resulting from cystic expansion with visceral compression, or rupture. The diagnosis can be made based on a detailed family history, followed by imaging studies (ultrasound, computed tomography, or magnetic resonance imaging). Genetic testing is reserved for atypical cases mostly. Common tools for prognosis prediction include total kidney volume, Mayo classification and PROPKD/genetic score. Screening and management of complications such as hypertension, proteinuria, urological infections, intracranial aneurysms, are also crucial for improving outcome. We suggest that the optimal management strategies of patients with ADPKD include general medical care, dietary recommendations and ADPKD-specific treatments. Key points include rigorous blood pressure control, dietary sodium restriction and Tolvaptan use, whereas the evidence for somatostatin analogues and mammalian target of rapamycin (mTOR) inhibitors remains limited. In summary, we outline an individualized care plan emphasizing careful monitoring of disease progression and highlight the need for shared decision-making among these patients.


Assuntos
Falência Renal Crônica , Rim Policístico Autossômico Dominante , Humanos , Rim Policístico Autossômico Dominante/diagnóstico , Rim Policístico Autossômico Dominante/terapia , Rim Policístico Autossômico Dominante/complicações , Taiwan/epidemiologia , Tolvaptan , Rim
2.
J Dent Educ ; 87(8): 1113-1122, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37143260

RESUMO

PURPOSE/OBJECTIVE: To assess the impact of local anesthesia (LA) course for physician assistant (PA) and adult gerontology-acute care nurse practitioner (NP) program students on knowledge, attitudes, confidence, and intention to incorporate skills in clinical practice. METHODS: The course was conducted by dental faculty for forty-eight PA and seven NP students and consisted of two lecture hours on anatomy of the oral cavity, anesthesia and pain management, 2 hours of preclinic lab where participants practiced injection technique on mannikins, and a clinical practicum conducted by dental school faculty and residents where students observed dental treatment including administration of LA, and discussed symptom triage by NPs and PAs for patients with dental problems including orofacial pain, initial management including LA, and patient referral to dentists. An online survey was administered to all students before and after the course to assess changes in knowledge, attitudes, confidence, and intention to incorporate LA administration skills into clinical practice and elicit students' perception of program quality. Pre- to post-changes were analyzed by two-tailed t-tests and analysis of variance (ANOVA) with significance at 0.05. RESULTS: The response rate for pre- and post-course assessment was 96.4% and 87.3% respectively. Students' overall scale score for self-assessment of dental knowledge increased significantly from pre- (2.34) to post-assessment (4.19). An increase was seen in students' attitudes regarding management of dental emergencies (t = 2.181; p < 0.05). Furthermore, overall confidence of students related to managing patients with dental problems increased significantly (2.00 to 3.85) after taking the course. CONCLUSION: The LA course was well received by PA and NP students and resulted in increased knowledge and confidence in recognizing common oral health conditions, understanding dental pain management including administration of LA, and making referrals to dentists to optimize patient care.


Assuntos
Profissionais de Enfermagem , Assistentes Médicos , Adulto , Humanos , Anestesia Local , Educação Interprofissional , Atitude do Pessoal de Saúde , Profissionais de Enfermagem/educação , Estudantes de Odontologia
4.
Nat Commun ; 14(1): 21, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36596763

RESUMO

Self-assembled systems have recently attracted extensive attention because they can display a wide range of phase morphologies in nanocomposites, providing a new arena to explore novel phenomena. Among these morphologies, a bicontinuous structure is highly desirable based on its high interface-to-volume ratio and 3D interconnectivity. A bicontinuous nickel oxide (NiO) and tin dioxide (SnO2) heteroepitaxial nanocomposite is revealed here. By controlling their concentration, we fabricated tuneable self-assembled nanostructures from pillars to bicontinuous structures, as evidenced by TEM-energy-dispersive X-ray spectroscopy with a tortuous compositional distribution. The experimentally observed growth modes are consistent with predictions by first-principles calculations. Phase-field simulations are performed to understand 3D microstructure formation and extract key thermodynamic parameters for predicting microstructure morphologies in SnO2:NiO nanocomposites of other concentrations. Furthermore, we demonstrate significantly enhanced photovoltaic properties in a bicontinuous SnO2:NiO nanocomposite macroscopically and microscopically. This research shows a pathway to developing innovative solar cell and photodetector devices based on self-assembled oxides.

5.
ACS Appl Mater Interfaces ; 14(19): 22278-22286, 2022 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-35523210

RESUMO

Relaxor ferroelectric-based energy storage systems are promising candidates for advanced applications as a result of their fast speed and high energy storage density. In the research field of ferroelectrics and relaxor ferroelectrics, the concept of solid solution is widely adopted to modify the overall properties and acquire superior performance. However, the combination between antiferroelectric and paraelectric materials was less studied and discussed. In this study, paraelectric barium hafnate (BaHfO3) and antiferroelectric lead hafnate (PbHfO3) are selected to demonstrate such a combination. A paraelectric to relaxor ferroelectric, to ferroelectric, and to antiferroelectric transition is observed by varying the composition x in the (Ba1-xPbx)HfO3 solid solution from 0 to 100%. It is noteworthy that ferroelectric phases can be realized without primal ferroelectric material. This study creates an original solid solution system with a rich spectrum of competing phases and demonstrates an approach to design relaxor ferroelectrics for energy storage applications and beyond.

6.
Small ; 18(19): e2107540, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35322548

RESUMO

Polar domain walls in centrosymmetric ferroelastics induce inhomogeneity that is the origin of advantageous multifunctionality. In particular, polar domain walls promote charge-carrier separation and hence are promising for energy conversion applications that overcome the hurdles of the rate-limiting step in the traditional photoelectrochemical water splitting processes. Yet, while macroscopic studies investigate the materials at the device scale, the origin of this phenomenon in general and the emergence of polar domain walls during the structural phase transition in particular has remained elusive, encumbering the development of this attractive system. Here, it is demonstrated that twin domain walls arise in centrosymmetric BiVO4 films and they exhibit localized piezoelectricity. It is also shown that during the structural phase transition from the tetragonal to monoclinic, the symmetry reduction is accompanied by an emergence of strain gradient, giving rise to flexoelectric effect and the polar domain walls. These results not only expose the emergence of polar domain walls at centrosymmetric systems by means of direct observation, but they also expand the realm of potential application of ferroelastics, especially in photoelectrochemistry and local piezoelectricity.

7.
Sensors (Basel) ; 23(1)2022 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-36616777

RESUMO

Measuring motor performance in individuals with intellectual disabilities (ID) is quite challenging. The objective of this study was to compare the motor performances of individuals with ID and those with typical development (TD) during soccer dribbling through video-based behavior-coded movement assessment along with a wearable sensor. A cross-sectional research design was adopted. Adolescents with TD (N = 25) and ID (N = 29) participated in the straight-line and zigzag soccer dribbling tests. The dribbling performance was videotaped, and the footage was then analyzed with customized behavior-coding software. The coded parameters were the time for movement completion, the number of kicks, blocks, steps, the number of times the ball went out of bounds, the number of missed cones, and the trunk tilt angle. Participants with ID exhibited significantly poorer performance and demonstrated greater variances in many time and frequency domain parameters. It also revealed that participants with ID kicked with both feet while dribbling, whereas those with TD mainly used the dominant foot. The present findings demonstrated how the ID population differed from their peers in lower-extremity strategic control. The customized video-based behavior-coded approach provides an efficient and effective way to gather behavioral data and calculate performance parameter statistics in populations with intellectual disabilities.


Assuntos
Deficiência Intelectual , Futebol , Humanos , Adolescente , Estudos Transversais , Perna (Membro) , Extremidade Inferior
8.
ACS Appl Mater Interfaces ; 13(18): 21186-21193, 2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-33905241

RESUMO

Flexible electronics has recently captured extensive attention due to its intriguing functionalities and great potential for influencing our daily life. In addition, with the increasing demand for green energy, photoelectrochemical (PEC) water splitting is a clean process that directly converts solar energy to chemical energy in the form of hydrogen. Thus the development of flexible green energy electronics represents a new domain in the research field of energy harvesting. In this work, we demonstrate the BiVO4 (BVO)/WO3/ITO/muscovite heterostructure photoelectrode for water splitting with flexible characteristics. The performance of BVO was modified by specific crystal facets, and the BVO/WO3 bilayer exhibited superior performance of 33% enhanced PEC activity at 1 V vs Ag/AgCl compared with pure BVO due to the proper staggered band alignment. Moreover, excellent mechanical stability was verified by a series of bending modes. This study demonstrates a pathway to a flexible photoelectrode for developing innovative devices for solar fuel generation.

9.
J Biosci Bioeng ; 129(5): 603-612, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31992527

RESUMO

The purpose of this study is to investigate the effect of soil organic matter (SOM) content levels on the biodegradation of total petroleum hydrocarbons (TPH). Batch experiments were conducted with soils with 2% or 10% organic matter that had been contaminated by diesel or fuel oil. In addition to the TPH (diesel or fuel oil) degradation efficiency, a comprehensive investigation was conducted on the TPH-degrading microbial community using molecular tools including oligonucleotide microarray technique and terminal restriction fragment length polymorphism analysis (T-RFLP). TPH was reduced from 10,000 mg/kg to 1849-4352 mg/kg dry weight soil. Higher biodegradation efficiencies and kinetic rate constants were observed in higher SOM contents. Hydrocarbon fractional analyses were conducted to explain the optimal operation with relatively low resin and aromatic fractions detected at the end of the remediation. The bacterial and fungal counts in the 10% SOM were approximately 10 CFU/g to 102 CFU/g above those in the 2% SOM, and the lowest fungal level was found when the least TPH degradability was measured. The internal transcribed spacer microarray identified the microorganisms that were introduced and proved their survival. The associated growth pattern confirmed that different kinds of contamination oils affected the microbial community diversity over time. Both the microarray and T-RFLP profiles indicated that Gordonia alkanivorans, G. desulfuricans, and Rhodococcus erythoropolis were the dominant bacteria, while Fusarium oxysporum and Aspergillus versicolor were the dominant fungi. The T-RFLP-derived nonmetric multidimensional scaling concluded that the dynamics of the microbial communities were impacted by the TPH degradation stages.


Assuntos
Bactérias/metabolismo , Hidrocarbonetos/metabolismo , Petróleo/metabolismo , Poluentes do Solo/metabolismo , Solo/química , Biodegradação Ambiental , Óleos Combustíveis/análise , Gasolina/análise , Bactéria Gordonia/metabolismo , Óleos/metabolismo , Petróleo/análise , Microbiologia do Solo , Poluentes do Solo/análise
10.
Chemosphere ; 233: 843-851, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340410

RESUMO

The bioremediation efficiency of petroleum hydrocarbons in natural soil-water systems is regulated by active microbial populations and other system parameters. Relevant factors include the transfer rate of petroleum contaminants from a medium into microorganisms, the partitioning behavior of contaminants from water into the soil organic matter (SOM), and the influence of the dissolved organic matter (DOM) on the contaminant level in water. The objectives of this study was aimed to determine the correlation among bioavailability of petroleum hydrocarbons, SOM content, and DOM level in soil-water systems. Heptadecane, pristane, and decylcyclohexane were selected as model hydrocarbon contaminants. The bioavailability of target contaminants in soil was examined using soils of different SOM contents (2% and 20%) in slurry bioreactors. In addition, the contaminant bioavailability as affected by various DOM levels (0-100 mgC/L) was also examined. The results showed that the SOM content affected the degrading rate of hydrocarbons significantly, where the rate constant was 4 times higher in 2% SOM microcosm than in the 20% SOM bioreactor for heptadecane degradation. Similarly, the pristane degrading efficiency after 240 h operation was 95% for the 2% SOM microcosm and only 38% for the 20% SOM microcosm. The hydrocarbon degradation rates in water phase were found to be enhanced by the added DOM level. A positive correlation existed between the contaminant bioavailability and the contaminant level in water as impacted by the SOM content in soil and the DOM level in water.


Assuntos
Alcanos/metabolismo , Cicloexanos/metabolismo , Bactéria Gordonia/metabolismo , Petróleo/metabolismo , Poluentes do Solo/análise , Terpenos/metabolismo , Poluentes Químicos da Água/análise , Biodegradação Ambiental , Disponibilidade Biológica , Reatores Biológicos/microbiologia , Solo/química , Microbiologia do Solo , Água/química
11.
ACS Appl Mater Interfaces ; 11(29): 25882-25890, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31257841

RESUMO

With the rise of Internet of Things, the presence of flexible devices has attracted significant attention owing to design flexibility. A ferroelectric field-effect transistor (FeFET), showing the advantages of high speed, nondestructive readout, and low-power consumption, plays a key role in next-generation technology. However, the performance of these devices is restricted since conventional flexible substrates show poor thermal stability to integrate traditional ferroelectric materials, limiting the compatibility of wearable devices. In this study, we adopt flexible muscovite mica as a substrate due to its good thermal properties and epitaxial integration ability. A flexible FeFET composed of oxide heteroepitaxy on muscovite is realized by combining an aluminum-doped zinc oxide film as the semiconductor channel layer and a Pb(Zr0.7Ti0.3)O3 film as the ferroelectric gate dielectric. The excellent characteristics of the transistor together with superior thermal stability and mechanical flexibility are demonstrated through various mechanical bending and temperature measurements. The on/off current ratio of the FeFET is higher than 103, which based on the field effect in the transfer curve. The smallest bending radius that can be achieved is 5 mm with a cyclability of 300 times and a retention of 100 h. This study opens an avenue to use oxide heteroepitaxy to construct a FeFET for next-generation flexible electronic systems.

12.
Chemosphere ; 233: 697-704, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31195274

RESUMO

Trichloroethylene (TCE) is one of the most ubiquitous halogenated organic compounds of concerns of carcinogens in groundwater in Taiwan. Bioremediation has been recognized as a cost-effective approach in reducing TCE concentration. Five pilot-scale wells were constructed to monitor TCE concentrations in contaminated groundwater. With injection of EOS®, TCE was effectively degraded to 42%-93% by the end of 175 days. The biostimulation with EOS® was useful in establishing a micro-site anaerobic but with limited contribution. Dilution of the aquifer movement also caused the TCE reduction among injection and monitoring wells. The degradability was affected by the location and the proximity from the injection well. TCE concentrations found to be negatively correlated with the associated Dehalococcoides spp. and functional genes levels. Dhc concentration of 108 copies L-1 caused the initial 40% of TCE degradation. The well with the optimal degradation owned tceA of 109 cells L-1. T-RFLP results indicate the wells with the superior TCE degradability also performed the highest Shannon index number (means the highest diversity), which occurred on the same day that Dhc levels started to enlarge. Desulfovibrio desulfuricans and Desulfuromonas chloroethenica were predominant species identified in the T-RFLP fingerprint profile. In brief, a variety of different factors including well locations, geochemical indicators, and microbial contribution were useful to explain the site-specific optimal TCE remediation approach. The consistence among TCE degradation, Dhc growing pattern, functional gene levels, and the dynamics of the microbial community structure present the novelty of this study.


Assuntos
Recuperação e Remediação Ambiental/métodos , Tricloroetileno/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Chloroflexi/metabolismo , Água Subterrânea/química , Halogenação , Microbiota , Taiwan , Tricloroetileno/análise , Tricloroetileno/química , Poluentes Químicos da Água/análise
13.
ACS Appl Mater Interfaces ; 11(2): 2205-2210, 2019 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-30408951

RESUMO

Self-assembled heteroepitaxial nanostructures have played an important role for miniaturization of electronic devices, e.g., the ultrahigh density ferroelectric memories, and cause for great concern. Our first principle calculations predict that the materials with low formation energy of the interface ( Ef) tend to form matrix structure in self-assembled heteroepitaxial nanostructures, whereas those with high Ef form nanopillars. Under the guidance of the theoretical modeling, perovskite BiFeO3 (BFO) nanopillars are swimmingly grown into CeO2 matrix on single-crystal (001)-SrTiO3 (STO) substrates by pulsed laser deposition, where CeO2 has a lower formation energy of the interface ( Ef) than BFO. This work provides a good paradigm for controlling self-assembled nanostructures as well as the application of self-assembled ferroelectric nanoscale memory.

14.
ACS Appl Mater Interfaces ; 10(36): 30574-30580, 2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-30118205

RESUMO

In the era of Internet of Things, the demand for flexible and transparent electronic devices has shifted to the forefront of materials science research. However, the radiation damage to key performance of transparent devices under radiative environment remains as a critical issue. Here, we present a promising technology for nonvolatile transparent electronic devices based on flexible oxide heteroepitaxy. A direct fabrication of epitaxial lead lanthanum zirconate titanate on transparent flexible mica substrate with indium tin oxide electrodes is presented. The transparent flexible ferroelectric heterostructures not only retain their superior performance, thermal stability, reliability, and mechanical durability, but also exhibit remarkably robust properties against to a strong radiation exposure. Our study demonstrates an extraordinary concept to realize transparent flexible nonvolatile electronic devices for the design and development of next-generation smart devices with potential application in electronics, automotive, aerospace, and nuclear systems.

15.
ACS Appl Mater Interfaces ; 8(48): 32754-32763, 2016 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-27934128

RESUMO

Understanding of charge transfer processes is determinant to the performance optimization for semiconductor photocatalysts. As a representative model of composite photocatalysts, metal-particle-decorated ZnO has been widely employed for a great deal of photocatalytic applications; however, the dependence of charge carrier dynamics on the metal content and metal composition and their correlation with the photocatalytic properties have seldom been reported. Here, the interfacial charge dynamics for metal-decorated ZnO nanocrystals were investigated and their correspondence with the photocatalytic properties was evaluated. The samples were prepared with a delicate antisolvent approach, in which ZnO nanocrystals were grown along with metal particle decoration in a deep eutectic solvent. By modulating the experimental conditions, the metal content (from 0.6 to 2.3 at%) and metal composition (including Ag, Au, and Pd) in the resulting metal-decorated ZnO could be readily controlled. Time-resolved photoluminescence spectra showed that an optimal Au content of 1.3 at% could effectuate the largest electron transfer rate constant for Au-decorated ZnO nanocrystals, in conformity with the highest photocatalytic efficiency observed. The relevance of charge carrier dynamics to the metal composition was also inspected and realized in terms of the energy level difference between ZnO and metal. Among the three metal-decorated ZnO samples tested, ZnO-Pd displayed the highest photocatalytic activity, fundamentally according with the largest electron transfer rate constant deduced in carrier dynamics measurements. The current work was the first study to present the correlations among charge carrier dynamics, metal content, metal composition, and the resultant photocatalytic properties for semiconductor/metal heterostructures. The findings not only helped to resolve the standing issues regarding the mechanistic foundation of photocatalysis but also shed light on the intelligent design of semiconductor/metal composite systems to consolidate their utility in photocatalytic fields.

16.
Appl Microbiol Biotechnol ; 99(3): 1485-97, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25261128

RESUMO

This study investigated methanogenic communities involved in degradation of tetramethylammonium hydroxide (TMAH) in three full-scale bioreactors treating TMAH-containing wastewater. Based on the results of terminal-restriction fragment-length polymorphism (T-RFLP) and quantitative PCR analyses targeting the methyl-coenzyme M reductase alpha subunit (mcrA) genes retrieved from three bioreactors, Methanomethylovorans and Methanosarcina were the dominant methanogens involved in the methanogenic degradation of TMAH in the bioreactors. Furthermore, batch experiments were conducted to evaluate mcrA messenger RNA (mRNA) expression during methanogenic TMAH degradation, and the results indicated that a higher level of TMAH favored mcrA mRNA expression by Methansarcina, while Methanomethylovorans could only express considerable amount of mcrA mRNA at a lower level of TMAH. These results suggest that Methansarcina is responsible for methanogenic TMAH degradation at higher TMAH concentrations, while Methanomethylovorans may be important at a lower TMAH condition.


Assuntos
Bactérias/metabolismo , Reatores Biológicos/microbiologia , Metano/metabolismo , Compostos de Amônio Quaternário/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Polimorfismo de Fragmento de Restrição , Esgotos/microbiologia
17.
Bioresour Technol ; 113: 303-10, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22456234

RESUMO

This study evaluated biological treatment of TMAH in a full-scale methanogenic up-flow anaerobic sludge blanket (UASB) followed by an aerobic bioreactor. In general, the UASB was able to perform a satisfactory TMAH degradation efficiency, but the effluent COD of the aerobic bioreactor seemed to increase with an increased TMAH in the influent wastewater. The batch test results confirmed that the UASB sludge under methanogenic conditions would be favored over the aerobic ones for TMAH treatment due to its superb ability of handling high strength of TMAH-containing wastewaters. Based on batch experiments, inhibitory chemicals present in TFT-LCD wastewater like surfactants and sulfate should be avoided to secure a stable methanogenic TMAH degradation. Finally, molecular monitoring of Methanomethylovorans hollandica and Methanosarcina mazei in the full-scale plant, the dominant methanogens in the UASB responsible for TMAH degradation, may be beneficial for a stable TMAH treatment performance.


Assuntos
Hidróxidos/metabolismo , Poluentes Químicos da Água/isolamento & purificação , Hidróxido de Amônia , Sequência de Bases , Primers do DNA , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição
18.
Environ Technol ; 33(22-24): 2661-72, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23437667

RESUMO

Bioremediation of diesel-contaminated soil was investigated for the effects of soil organic matter (SOM) and ageing time in two sets of experiments (Batch I and II, respectively). This study examined degradation efficiency in soil artificially contaminated with diesel oil (maximum total petroleum hydrocarbons (TPH) concentration of 9000 mg/kg soil). Batch I data showed that the values of the first-order degradation rate, k, were relatively high in the low-SOM soil batches. The quantity of SOM negatively correlated with the TPH degradation rates and with the total TPH degradation efficiency (%). Introduction of rhamnolipid to the soil proved to be a useful solution to resolve the problem of the residual TPH in the soil with high SOM. In Batch II, the k values decreased with the length of ageing time: 0.0245, 0.0128 and 0.0090 l/d in samples ST0 (freshly contaminated), ST38 (aged for 38 days) and ST101 (aged for 101 days), respectively. The TPH degradation efficiency (%) also decreased along with the ageing time. The research also applied molecular technology to analyse the bacterial community dynamics during the bioremediation course. Multivariate statistics based on terminal-restriction fragment length data indicated: 1) the soils with different SOM resulted in separate bacterial community structures, 2) ageing time created a variety of bacterial communities, 3) the bacterial community dynamics was associated with the hydrocarbon consumption. The SOM content in soils affected the TPH degradation rate and efficiency and the bacterial community structures. Aged soil is more difficult to remediate than freshly contaminated soil, and the resulting bacterial community was less dynamic and showed a lack of succession.


Assuntos
Recuperação e Remediação Ambiental , Gasolina , Poluentes do Solo/isolamento & purificação , Sequência de Bases , Biodegradação Ambiental , Primers do DNA , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição
19.
J Hazard Mater ; 164(2-3): 1045-50, 2009 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-18950937

RESUMO

This study investigated the effects of pH and ammonium concentrations on the potential application of two biosurfactants, surfactin (SF) and rhamnolipid (RL), for enhanced diesel biodegradation with a series of bench-scale experiments. In general, compared to the experiments without biosurfactant addition, adding RL or SF to diesel-water systems at concentrations above their critical micelle concentration (CMC) values benefited diesel emulsification, and therefore enhanced diesel biodegradation. The effects of pH on RL or SF-enhanced biodegradation of diesel were in good agreement with the trends of emulsion index values for RL or SF addition, respectively, under different pH conditions, suggesting that enhanced diesel emulsification by RL or SF addition promoted biodegradation of diesel. In diesel-water systems with 50mg/L of RL addition, an optimum pH condition for microbial growth and diesel biodegradation was found to be at a pH 7.2, while decreasing pH to 5.2 or increasing it to 8.4 reduced those parameters considerably. For the cases where 40 mg/L of SF was added, the enhancing ability shared a general trend with that observed for adding 50mg/L of RL as the pH increased from 5.2 to 7.2. Further increase of pH to 8.4, however, did not seem to negatively influence biodegradation and biomass growth. With respect to the effects of ammonium concentration on diesel biodegradation in diesel-water systems with 50mg/L of RL addition, an optimum ammonium addition for microbial growth and diesel biodegradation was found between 200 and 300 mg-N/L, but a dramatic decrease in growth and biodegradation occurred at ammonium addition up to 450 mg-N/L. For the cases where 40 mg/L of SF was added, an increase of ammonium addition from 50 to 200mg-N/L substantially increased microbial growth and biodegradation of diesel. Further increase of ammonium concentration to 450 mg-N/L, however, did not further improve diesel biodegradation.


Assuntos
Biodegradação Ambiental , Gasolina/microbiologia , Glicolipídeos , Lipopeptídeos , Peptídeos Cíclicos , Compostos de Amônio Quaternário , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Biomassa , Concentração de Íons de Hidrogênio , Tensoativos
20.
Sci Total Environ ; 398(1-3): 154-63, 2008 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-18448149

RESUMO

This study investigates source impacts by airborne volatile organic compounds (VOC) at two sites designated for traffic and industry, in the largest industrial area Kaohsiung, southern Taiwan. The samples were collected at the two sites simultaneously during rush and non-rush hours in summer and autumn seasons. Same pattern of VOC groups were found at both sites: most abundant aromatics (78-95%) followed by alkanes (2-16%) and alkenes (0-6%). The BTEX concentration measured at the two sites ranged from 69 to 301 ppbC. Toluene, isopentane, ethylbenzene, and benzene were found to be the most abundant species. Speciation of VOCs was characterized with several skills including principal component factor analysis and BTEX characteristic ratios. Each of the resulted principal factors at the two sites explained over 80% of the VOCs data variance, and indicated that both of the sampling sites were influenced by both traffic and industrial sources with separately different levels. The remarkable patterns of the first two factors described not only the similarity but also the discrepancy at the two sampling sites, in terms of the source impacts. The high T/B ratios (7.56-14.25) observed at the industrial site implied the important impact from mobile emissions. The indicators, m,p-xylene/benzene and o-xylene/benzene, also confirmed the potential source of motor vehicles at both of the sampling sites. Air age assessment showed that more than half of the total observations located in the domain of fresh air. Low X/E ratios implied somewhat aged air mass transported to the sampling sites. The industrial site might not only encounter emissions from the industry sources, but also under unavoidable impact from the traffic sources.


Assuntos
Poluentes Atmosféricos/análise , Compostos Orgânicos/análise , Cidades , Monitoramento Ambiental , Indústrias , Taiwan , Emissões de Veículos
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