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1.
J Hosp Infect ; 151: 131-139, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39032564

RESUMEN

Midline catheters (MCs) and peripherally inserted central catheters (PICCs) are essential for reliable vascular access in patients. Despite their prevalent use, comparative risk assessments of these catheters, particularly from randomized controlled trials (RCTs), remain scarce. This meta-analysis primarily focuses on RCTs to evaluate and compare the incidence of complications associated with MCs and PICCs. We conducted a comprehensive search of databases including the Cochrane Library, PubMed, Embase, Web of Science, ScienceDirect, Scopus and ProQuest, up to April 2024. The primary outcomes analysed were total complications and catheter-related bloodstream infections (CRBSIs), while secondary outcomes included catheter dwell time and thrombosis incidence. Meta-analyses were performed using a random-effects model. Of 831 initially identified articles, five trials involving 608 patients met the inclusion criteria. MCs exhibited a significantly higher rate of total complications compared with PICCs (relative risk = 1.95, 95% confidence interval = 1.23-3.08, P=0.005, I2= 0%). MCs also had shorter dwell times and a higher incidence of premature removal. However, no significant differences were observed in the rates of CRBSIs or thrombosis between MCs and PICCs. PICCs are associated with fewer total complications and longer dwell times compared with MCs, which tend to be more often removed prematurely. Thrombosis rates were similar between the two catheter types, underscoring the need for careful catheter selection based on specific patient conditions and treatment duration. Further research, particularly additional RCTs, is necessary to confirm these findings and guide optimal catheter selection in clinical practice.


Asunto(s)
Infecciones Relacionadas con Catéteres , Cateterismo Periférico , Ensayos Clínicos Controlados Aleatorios como Asunto , Humanos , Infecciones Relacionadas con Catéteres/epidemiología , Cateterismo Periférico/efectos adversos , Incidencia , Cateterismo Venoso Central/efectos adversos , Trombosis/etiología , Trombosis/epidemiología , Persona de Mediana Edad , Masculino , Femenino , Anciano , Catéteres Venosos Centrales/efectos adversos , Adulto
2.
Chem Commun (Camb) ; 51(73): 13910-3, 2015 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-26239759

RESUMEN

We present a novel approach to remove the structure-directing agent (SDA) from as-synthesized zeolites using an atmospheric pressure plasma jet (APPJ). This reduces the time required to less than 60 seconds as compared to the existing thermal calcination, whose durations range from hours to days. The highly reactive plasma also results in a pronounced Q(3)-to-Q(4) transformation in the pure-silica zeolite MFI.

3.
Med J Malaysia ; 69(2): 95-7, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25241821

RESUMEN

Langerhans Cell Histiocytosis (LCH) is an uncommon neoplastic disorder characterized by accumulation of histiocytes in various tissues. The clinical manifestation is highly variable, ranging from an isolated skin rash or a single bony lesion, to fatal multi-organ failure. Due to its rarity and systemic involvement, the epidemiology of LCH is still not fully understood and most studies focus on the paediatric population. The extent of clinical involvement has important prognostic implications. Treatment options may be local or systemic depending on disease extent. Here we describe a rare case of adult onset LCH who presented with recurrent pneumothoraces, diabetes insipidus and papules and plaques over the scalp and forehead.

4.
J Pediatr Urol ; 10(6): 1227-31, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25214038

RESUMEN

INTRODUCTION: Patients with lower urinary tract anomalies or neurogenic disorders often suffer from voiding difficulties. Clean intermittent catheterization (CIC) is effective for bladder drainage; however, this is often painful. Transurethral catheterization is also impossible in patients with urethral stricture. A Mitrofanoff conduit may solve some of these problems, but a few disadvantages have been reported, including: difficult surgical techniques and frequent operative complications. A vesicostomy is easy to perform but persistent urine leak over the abdomen and diaper rash can be annoying. A better way to achieve continent urinary diversion is indicated. METHOD: Between December 01 1998 and December 31 2013, six patients underwent a vesico-cutaneous fistula for CIC. The etiologies included urethral stricture (n=2) and neurogenic bladder (n=4). The fistula was created at the bladder dome with only the muscle layer of the bladder sutured to the skin. A Foley catheter was left in place for at least two weeks to prevent stoma stricture. After removing the Foley catheter, regular CIC from the fistula was performed every 2 h during the daytime with a Fr. 10-12 feeding tube, depending on the patient's age. Further stenting during the night in the first six months was necessary to prevent early closure of the fistula. Patients were followed with periodic renal ultrasonography, blood tests and urinalysis in the outpatient department. RESULTS: Follow-up ranged from 6 months to 16 years. All patients showed improvements in hydronephrosis. Decreased UTI frequency was seen in five patients. Renal function was normal in five patients, whilst the other suffered from chronic renal failure preoperatively. Only one patient had occasional mild urine leakage from the stoma at night, which was once in two weeks. No patient experienced painful or difficult catheterization and CIC becomes easy, even by young children. CONCLUSIONS: The vesico-cutaneous fistula is a simple, effective and tolerable method for CIC. It may be a substitute for or a transition to a Mitrofanoff conduit in some patients.


Asunto(s)
Estrechez Uretral/cirugía , Vejiga Urinaria Neurogénica/cirugía , Cateterismo Urinario/métodos , Derivación Urinaria/métodos , Procedimientos Quirúrgicos Urológicos/métodos , Adolescente , Niño , Preescolar , Cistostomía , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Resultado del Tratamiento , Adulto Joven
5.
J Appl Phys ; 113(3): 33706, 2013 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-23405036

RESUMEN

The intrinsic oxygen-vacancies and the extrinsic dopants are two major fundamental free-carrier sources for the extrinsic conducting oxides, such as Sn-doped In(2)O(3). Yet, the individual contributions of the above two free-carrier sources to the total carrier concentrations have never been unraveled. A carrier-concentration separation model is derived in this work, which can define the individual contributions to the total carrier concentration from the intrinsic oxygen-vacancies and the extrinsic dopants, separately. The individual contributions obtained from the present carrier-concentration separation model are verified by the two-state trapping model, photoluminescence, and positron annihilation lifetime (PAL) spectroscopy. In addition, the oxygen-vacancy formation energy of the Sn:In(2)O(3) thin film is determined to be 0.25 eV by PAL spectroscopy.

6.
Aliment Pharmacol Ther ; 34(4): 424-31, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21692822

RESUMEN

BACKGROUND: Previous studies suggested that a finite course of peginterferon alfa-2a may offer an alternative rescue therapy for patients with lamivudine resistance. However, because of the limitation of study design and small sample size, it is difficult to make definitive conclusion. AIM: To explore the role of peginterferon alfa-2a, in the rescue treatment of HBeAg-positive chronic hepatitis B patients with lamivudine resistance. METHODS: In this randomised study, chronic hepatitis B patients with lamivudine resistance were treated with peginterferon alfa-2a for 48 weeks (n=155) or adefovir for 72 weeks (n=80). All enrolled patients were treated with lamivudine for the first 12weeks. RESULTS: At 6 months posttreatment, 14.6% (18/123) of peginterferon alfa-2a-treated patients achieved HBeAg seroconversion, in contrast to 3.8% (3/80) of adefovir-treated patients after 72 weeks continuous therapy (P=0.01). For peginterferon alfa-2a-treated patients, the rate of HBeAg seroconversion at week 72 was significantly higher in patients who had HBsAg decline >0.5 Log(10) IU/mL from baseline at week 24, compared with patients with HBsAg decline ≤0.5 Log(10) IU/mL from baseline at week 24 (25.5% vs. 7.7%, P=0.01). After 72 weeks continuous adefovir treatment, 22.5% of patients achieved HBV DNA <80 IU/mL, compared with 10.6% in peginterferon alfa-2a-treated patients at 6months off-treatment (P=0.02). CONCLUSIONS: Overall, the response to peginterferon alfa-2a among patients with lamivudine resistance was suboptimal. HBeAg seroconversion rate at week 72 by 48 weeks peginterferon alfa-2a treatment was higher than continuous adefovir therapy. Monitoring HBsAg levels can help to predict response to peginterferon alfa-2a.


Asunto(s)
Adenina/análogos & derivados , Antivirales/uso terapéutico , Farmacorresistencia Viral/efectos de los fármacos , Hepatitis B Crónica/tratamiento farmacológico , Interferón-alfa/uso terapéutico , Lamivudine/uso terapéutico , Organofosfonatos/uso terapéutico , Polietilenglicoles/uso terapéutico , Adenina/uso terapéutico , Adolescente , Adulto , Anciano , China , Quimioterapia Combinada , Femenino , Humanos , Interferón alfa-2 , Masculino , Persona de Mediana Edad , Proteínas Recombinantes , Factores de Tiempo , Resultado del Tratamiento , Adulto Joven
7.
Hong Kong Med J ; 16(6): 463-9, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21135423

RESUMEN

OBJECTIVE: To test our hypothesis that there is inadequate knowledge and awareness of hepatitis B infection among the general population in Hong Kong. DESIGN: A random telephone survey using a structured multiple-choice questionnaire. SETTING: Hong Kong community. PARTICIPANTS: Hong Kong residents aged 18 years or above. RESULTS: A total of 506 respondents were successfully interviewed in February 2010. Approximately half of respondents (55%) were aware that hepatitis B virus is the most common cause of chronic viral hepatitis in Hong Kong. Regarding knowledge about the mode of transmission, mother-to-infant transmission and blood contact were recognised as risk factors by 67% and 65% of respondents, respectively. Transmission by sexual contact, sharing a razor or toothbrush, and tattooing or body piercing were appreciated by 44%, 41%, and 37% of respondents, respectively. A majority (73%) had the mistaken belief that the virus is transmitted by eating contaminated seafood. Over half of respondents (53%) knew nothing about the clinical presentation of acute hepatitis B. Only 35% of respondents realised that periodic abdominal ultrasonographic examinations are indicated for asymptomatic hepatitis B carriers. While 51% of respondents reported being tested for hepatitis B virus infection, only 36% acknowledged being vaccinated against the infection. Education level, occupation, and marital status were factors associated with both hepatitis B virus screening and vaccination. CONCLUSION: These findings support our hypothesis that there is inadequate knowledge and awareness about hepatitis B infection in the general population in Hong Kong.


Asunto(s)
Conocimientos, Actitudes y Práctica en Salud , Hepatitis B/prevención & control , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Hepatitis B/transmisión , Humanos , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios , Teléfono , Vacunación
8.
Eur J Pediatr Surg ; 20(2): 82-4, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19899040

RESUMEN

INTRODUCTION: Various scales and measurement methods including X-rays and computed tomography (CT) have been used to quantify the degree of deformity in pectus excavatum. This study describes a non-invasive method for recording the deviation of the anterior chest wall (ACW) in pectus excavatum (PE) patients. Data obtained using this non-invasive method were compared with CT data. MATERIALS AND METHODS: Twenty-one patients treated at our institutions between June 2008 and February 2009 were enrolled in this study. All patients underwent CT and thermal plastic strip measurement. A thermal plastic strip was positioned and taped to the supine patient's ACW at the skin level from the posterior axillary line, over the depressed sternum, to the contralateral posterior axillary line and used to create a casting of the ACW. RESULTS: The funnel index (FI) was defined as the width of the ACW divided by its height; the concave index (CI) was defined as the breadth of the depressed area of the funnel chest divided by its depth. Pearson's correlation coefficient was used to compare the FI and CI obtained with the thermal plastic strip method and with CT; measurements obtained with both methods were found to correlate well (FI: r (2)=0.965; CI: r (2)=0.947). CONCLUSIONS: The thermal plastic strip measurement method provides a two-dimensional record of the shape of the anterior chest wall. The measurement can be repeated, does not involve the patient being exposed to radiation, and offers a good longitudinal assessment of chest wall growth in PE patients.


Asunto(s)
Pesos y Medidas Corporales/métodos , Tórax en Embudo/diagnóstico , Tórax en Embudo/cirugía , Pared Torácica/anatomía & histología , Adolescente , Niño , Preescolar , Femenino , Humanos , Masculino , Resultado del Tratamiento
9.
Appl Microbiol Biotechnol ; 85(3): 773-8, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19809812

RESUMEN

Nitrite accumulates during biological denitrification processes when carbon sources are insufficient. Acetate, methanol, and ethanol were investigated as supplementary carbon sources in the nitrite denitrification process using biogranules. Without supplementary external electron donors (control), the biogranules degraded 200 mg l(-1) nitrite at a rate of 0.27 mg NO(2)-N g(-1) VSS h(-1). Notably, 1,500 mg l(-1) acetate and 700 mg l(-1) methanol or ethanol enhanced denitrification rates for 200 mg l(-1) nitrite at 2.07, 1.20, and 1.60 mg NO(2)-N g(-1) VSS h(-1), respectively; these rates were significantly higher than that of the control. The sodium dodecyl sulfate polyacrylamide gel electrophoresis of the nitrite reductase (NiR) enzyme identified three prominent bands with molecular weights of 37-41 kDa. A linear correlation existed between incremental denitrification rates and incremental activity of the NiR enzyme. The NiR enzyme activity was enhanced by the supplementary carbon sources, thereby increasing the nitrite denitrification rate. The capacity of supplementary carbon source on enhancing NiR enzyme activity follows: methanol > acetate > ethanol on molar basis or acetate > ethanol > methanol on an added weight basis.


Asunto(s)
Acetatos/metabolismo , Etanol/metabolismo , Metanol/metabolismo , Nitritos/metabolismo , Nitrógeno/metabolismo , Microbiología del Agua , Electroforesis en Gel de Poliacrilamida , Peso Molecular , Nitrato-Reductasa/química , Nitrato-Reductasa/aislamiento & purificación
10.
Appl Microbiol Biotechnol ; 85(3): 753-62, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19789865

RESUMEN

The aerobic sludge granules cultivated at high organic loading rates could effectively convert 100-700 mg l(-1) nitrite to nitrogen gas with 400 or 1,200 mg l(-1) dosed acetate. The denitrifying microbial community structure of the so-cultivated granules was investigated by 16S rRNA gene sequences and localized using fluorescence in situ hybridization (FISH). The 16S rRNA gene phylotypes in the clone library and FISH probes used exhibited high diversity among the bacteria and denitrifying communities, with the members of Betaproteobacteria predominant that were closely related to families Comamonadaceae, Nitrosomonadaceae, Alcaligenaceae, and Rhodocyclaceae. The confocal laser scanning microscope and staining test revealed that active microbial community principally distributed at 200-250 microm beneath the outer surface, embedded in extracellular polymeric substances.


Asunto(s)
Bacterias Aerobias/clasificación , Bacterias Aerobias/genética , Biodiversidad , Nitritos/metabolismo , Nitrógeno/metabolismo , Aguas del Alcantarillado/microbiología , Bacterias Aerobias/metabolismo , Análisis por Conglomerados , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Hibridación Fluorescente in Situ , Microscopía Confocal , Microscopía Electrónica de Rastreo , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Coloración y Etiquetado
11.
Bioresour Technol ; 100(5): 1734-9, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18990565

RESUMEN

The concept of carbon credit arose out of increasing awareness of the need to reduce emissions of greenhouse gases to combat global warming which was formalized in the Kyoto protocol. In addition to contribution to sustainable development with energy recovery in the form of methane, carbon credits can be claimed by application of advanced anaerobic processes in wastewater treatment for reducing emissions of greenhouse gases. As anaerobic granular systems are capable of handling high organic loadings concomitant with high strength wastewater and short hydraulic retention time, they could render much more carbon credits than other conventional anaerobic systems. This study investigated the potential carbon credit derived from laboratory-scale upflow anaerobic sludge blanket (UASB) reactors based on a carbon balance analysis. Methane emission reduction could be calculated by calculating the difference of UASB reactors and open lagoon treatment systems. Based on the 2.5l bench-scale reactor, the total CH(4) emissions reduction was calculated as 29 kg CO(2)/year. On scaling up to a typical full-scale anaerobic digester, the total CH(4) emissions reduction could achieve 46,420 tons CO(2) reduction/year. The estimated carbon credits would amount to 278,500 US$ per year by assuming a carbon price of 6 US$ per metric ton CO(2) reduction. The analysis postulated that it is financially viable to invest in advanced anaerobic granular treatment system from the revenue generated from carbon credits.


Asunto(s)
Bacterias Anaerobias/metabolismo , Reactores Biológicos , Carbono/metabolismo , Conservación de los Recursos Naturales/métodos , Efecto Invernadero , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos , Metano/metabolismo
12.
Appl Microbiol Biotechnol ; 77(1): 175-82, 2007 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17710392

RESUMEN

Effect of air aeration intensities on granule formation and extracellular polymeric substances content in three identical sequential batch reactors were investigated. The excitation-emission-matrix spectra and multiple staining and confocal laser scanning microscope revealed proteins, polysaccharides, lipids, and humic substances in the sludge and granule samples. Seed sludge flocs were compacted at low aeration rate, with produced extracellular polymeric substances of 50.2-76.7 mg g(-1) of proteins, 50.2-77.3 mg g(-1) carbohydrates and 74 mg g(-1) humic substances. High aeration rate accelerated formation of 1.0-1.5 mm granules with smooth outer surface. The corresponding quantities of extracellular polymeric substances were 309-537 mg g(-1) of proteins, 61-109 mg g(-1) carbohydrates, 49-92 mg g(-1) humic substances, and 49-68 mg g(-1) lipids. Intermediate aeration rate produced 3.0-3.5 mm granules with surface filaments. Reactor failure occurred with overgrowth of filaments, probably owing to the deficiency of nutrient in liquid phase. No correlation was noted between extracellular polymeric substances composition and the proliferation of filamentous microorganisms on granule surface.


Asunto(s)
Fenol/metabolismo , Polímeros/análisis , Aguas del Alcantarillado/microbiología , Aerobiosis , Reactores Biológicos/microbiología , Sustancias Húmicas/análisis , Microscopía Confocal , Polisacáridos/análisis , Proteínas/análisis , Espectrometría de Fluorescencia
13.
Langmuir ; 23(15): 8042-7, 2007 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-17590025

RESUMEN

The spreading dynamics of power-law fluids, both shear-thinning and shear-thickening fluids, that completely or partially wet solid substrate was investigated theoretically and experimentally. An evolution equation for liquid-film thickness was derived using a lubrication approximation, from which the dynamic contact angle versus the contact line moving velocity relationship was evaluated. In the capillary spreading regime, film thickness h is proportional to xi3/(n+2) (xi is the distance from the contact line), whereas in the gravitational regime, h is proportional to xi1/(n+2), relating to the rheological power exponent n. The derived model fit the experimental data well for a shear-thinning fluid (0.2% w/w xanthan solution) or a shear-thickening fluid (7.5% w/w 10 nm silica in polypropylene glycol) on a completely wetted substrate. The derived model was extended using Hoffmann's proposal for partially wetting fluids. Good agreement was also attained between model predictions and the shear-thinning fluid (1% w/w cmc solution) and shear-thickening fluid (10% w/w 15 nm silica) on partially wetted surfaces.

14.
Aliment Pharmacol Ther ; 25(11): 1283-92, 2007 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-17509096

RESUMEN

BACKGROUND: Although chronic hepatitis C virus-infected patients with persistently normal alanine aminotransaminase levels usually have mild liver disease, disease progression can still occur. However, it is uncertain which group of patients is at risk of disease progression. AIM: To examine the severity of liver disease on liver biopsy in Chinese patients with persistently normal alanine aminotransaminase levels, and their disease progression over time. METHODS: Eighty-two patients with persistently normal alanine aminotransaminase levels were followed up longitudinally. The median time of follow-up was 8.1 years. Forty-seven of the 82 patients (57.3%) had a second liver biopsy. RESULTS: At the time of analysis, six of the 82 patients (7.3%) developed decompensated liver cirrhosis. Patients with an initial fibrosis stage F2 or F3 [6/23 (26.1%) vs. 0/59 (0%), P < 0.0001] or inflammatory grade A2 or A3 [5/40 (12.5%) vs. 1/42 (2.4%), P = 0.04] were more likely to develop decompensated liver cirrhosis. On multivariate analysis, initial fibrosis stage F2 or F3 was independently associated with progression to decompensated liver cirrhosis (relative risk 2.3, 95% confidence interval 0.03-2.5, P = 0.02). CONCLUSION: Chinese chronic hepatitis C virus patients with persistently normal alanine aminotransaminase levels with moderate to severe fibrosis at initial evaluation are more likely to develop decompensated liver cirrhosis.


Asunto(s)
Alanina Transaminasa/metabolismo , Hepatitis C Crónica/enzimología , Hígado/patología , Adulto , Biopsia , China/etnología , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Hepatitis C Crónica/etnología , Hepatitis C Crónica/patología , Humanos , Cirrosis Hepática/patología , Cirrosis Hepática/virología , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Prevalencia , Pronóstico , Factores de Riesgo
15.
Appl Microbiol Biotechnol ; 75(3): 685-91, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17294183

RESUMEN

The interior structure of aerobic granules is highly heterogeneous, hence, affecting the transport and reaction processes in the granules. The granule structure and the dissolved oxygen profiles were probed at the same granule in the current work for possible estimation of transport and kinetic parameters in the granule. With the tested granules fed by phenol or acetate as carbon source, most inflow oxygen was consumed by an active layer thickness of less than 125 microm on the granule surface. The confocal laser scanning microscopy scans also revealed a surface layer thickness of approximately 100 microm consisting of cells. The diffusivities of oxygen transport and the kinetic constant of oxygen consumption in the active layers only were evaluated. The theoretical models adopted in literature that ignored the contributions of the layered structure of aerobic granule could have overlooked the possible limitations on oxygen transport.


Asunto(s)
Consumo de Oxígeno , Oxígeno/metabolismo , Aguas del Alcantarillado/microbiología , Acetatos/metabolismo , Aerobiosis , Reactores Biológicos , Difusión , Microscopía Confocal , Oxidación-Reducción , Oxígeno/química , Fenol/metabolismo
16.
J Environ Manage ; 85(4): 1009-14, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17202026

RESUMEN

The Hsinchu Science-based Industrial Park (HSIP) is the hi-tech manufacturing hub of Taiwan. Wastewater from the HSIP contains numerous nano-sized silicate particles whose size distributions peak at 2 and 90 nm. A 3-5 mg l(-1) as Al dose of polyaluminum chloride (PACl) was used in the field to coagulate these particles, but the removal efficiency was low. Laboratory scale tests indicated that although PACl coagulation removed 52% of the turbidity and 48% of the chemical oxygen demand (COD) from water, its effect on nano-particle removal was minimal. About 58% of the soluble COD was associated with colloidal Si particles. A light scattering test and transmission electron microscopy (TEM) demonstrated that the nano-particles agglomerated in approximately linear aggregates of sizes 100-300 nm. Prolonged contact between residual PACl and the nano-particles generated large aggregates with sizes of up to 10 microm and a fractal dimension of 2.24-2.63. The results presented herein should be of interest in the processing of "high-tech" wastewater that contains nanosized silica particles.


Asunto(s)
Hidróxido de Aluminio/química , Residuos Industriales/análisis , Nanopartículas/química , Eliminación de Residuos Líquidos/métodos , Microscopía Electrónica de Transmisión , Nanopartículas/ultraestructura , Taiwán
17.
Water Res ; 41(4): 884-92, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17224172

RESUMEN

High biomass density and large size limit the transfer of dissolved oxygen (DO) in aerobic granules. In the literature, the oxygen diffusivity is often employed as an input parameter for modeling transport processes in aerobic granules. The interior of an aerobic granule was observed to be highly heterogeneous. In this work, the distributions of extracellular polymeric substances (EPS) and cells in the interior of phenol-fed and acetate-fed granules were built up using a five-fold staining scheme, combined with the use of a confocal laser scanning microscope (CLSM). The steady-state and transient DO with step changes in surrounding DO levels at various depths were measured in the granules using microelectrodes. Cells were probed in a surface layer of thickness 125-375 microm. A marked fall in DO was also noted over this surface layer. No aerobic oxidation could occur beneath the active layer, indicating the oxygen transfer limit. Fitting the steady-state and transient DO data over the active surface layer yielded apparent diffusivities of oxygen were (9.5+/-3.5)x10(-10)m(2)s(-1) for the phenol-fed granule and (3.5+/-1.0)x10(-10)m(2)s(-1) for the phenol-fed granule. These values were lower than those adopted in models in the literature.


Asunto(s)
Biomasa , Oxígeno/metabolismo , Eliminación de Residuos Líquidos , Acetatos/metabolismo , Aerobiosis , Reactores Biológicos , Difusión , Cinética , Microscopía Confocal , Oxidación-Reducción , Oxígeno/química , Fenol/metabolismo , Factores de Tiempo
18.
Appl Microbiol Biotechnol ; 74(3): 699-707, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17115206

RESUMEN

This study extracted the soluble microbial products and loosely bound and tightly bound extracellular polymeric substances (EPS) from suspended sludge from a membrane bioreactor, original and aerobically/anaerobically digested, and compared their fouling potentials on a microfiltration membrane. The resistance of cake layer accounts for 95-98% of the total filtration resistances when filtering the whole sludges, with anaerobically digested sludge presenting the highest resistance among the three tested sludges. The tightly bound EPS has the highest potential to foul the membrane; however, the loosely bound EPS contribute most of the filtration resistances of the whole sludges. The foulants corresponding to the irreversible fouling have chemical fingerprints similar to those from loosely bound EPS, which have a greater predilection to proteins and humic substances than to polysaccharides.


Asunto(s)
Biopolímeros/metabolismo , Reactores Biológicos , Análisis de Falla de Equipo , Filtración/instrumentación , Aguas del Alcantarillado/química , Aerobiosis , Anaerobiosis , Filtros Microporos
19.
Environ Sci Technol ; 40(21): 6642-6, 2006 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-17144290

RESUMEN

Membrane biofouling by microbial products adversely impacts the feasibility of adopting membrane bioreactors (MBRs) for treating wastewater. The fouling layer structure determines the pressure drop across the fouling layer. Three-dimensional distributions of nucleic acids, proteins, alpha-D-GLUCOPYRANOSE POLYSACCHARIDES, AND B-D-glucopyranose polysaccharides in the fouling layer formed on a mixed cellulose ester membrane were generated utilizing a quadruple staining protocol combined with confocal laser scanning microscopy (CLSM). For the first time, this study constructed a three-dimensional volumetric grids model representing the fouling layer structure on the basis of a series of CLSM images. Quantitative structural information about the fouling layer was extracted from the CLSM images.


Asunto(s)
Monitoreo del Ambiente/métodos , Membranas Artificiales , Polímeros/análisis , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/instrumentación , Bacterias/metabolismo , Biopelículas/crecimiento & desarrollo , Biopolímeros/análisis , Reactores Biológicos , Monitoreo del Ambiente/instrumentación , Colorantes Fluorescentes/farmacología , Rayos Láser , Microscopía Confocal , Polímeros/química , Aguas del Alcantarillado , Contaminantes Químicos del Agua , Purificación del Agua/métodos
20.
Pediatr Surg Int ; 22(8): 665-9, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16821019

RESUMEN

Colon perforation is an abdominal surgical emergency in the pediatric population, but is seldom reported when occurring from non-traumatic causes in children beyond the neonate. The goal of this study was to identify the clinical characteristics, management, and outcomes of non-traumatic colon perforation in children. Medical records for the 10-year period from September 1994 to September 2004 were reviewed for children beyond the neonate with non-traumatic colon perforation. Data gathered included age, gender, symptoms, duration of symptoms, physical findings, and length of postoperative hospital stay. Diagnostic information included laboratory data, radiographic imaging, and operative findings. Forty-four patients with non-traumatic colon perforation were recruited into this study. The mean age was 2.22 +/- 1.87 years; 91.4% of cases were younger than 5 years old. The most common presenting symptom was fever (97.7%); the most common sign was abdominal distention (93.1%). The mean duration of symptoms prior to admission was 6.19 days. Pneumoperitoneum was presented in 86.3% of patients by plain abdominal radiograph. Ascending and transverse colon were the most common perforation sites. Non-typhoid salmonella was the leading pathogen isolated, causing 20.4% of episodes. One case died due to Clostridium speticum infection. Non-traumatic colon perforation most commonly affects children younger than 5 years of age. It may be secondary to infection, especially non-typhoid salmonella. Plain abdominal radiograph can be an adjuvant tool for the high index of suspicion for colon perforation in children with abdominal distention and history of fever or diarrhea for more than 5 days.


Asunto(s)
Enfermedades del Colon/diagnóstico , Enfermedades del Colon/cirugía , Perforación Intestinal/diagnóstico , Perforación Intestinal/cirugía , Abdomen Agudo , Niño , Preescolar , Enfermedades del Colon/microbiología , Diagnóstico Diferencial , Diarrea , Femenino , Fiebre , Humanos , Lactante , Recién Nacido , Perforación Intestinal/microbiología , Masculino , Neumoperitoneo/etiología , Estudios Retrospectivos
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