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1.
Acta Trop ; 255: 107223, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38642694

RESUMO

Malaria remains a highly prevalent infectious disease worldwide, particularly in tropical and subtropical regions. Effectively controlling of mosquitoes transmitting of Plasmodium spp. is crucial in to control this disease. A promising strategy involves utilizing plant-derived products, such as the Neem tree (Azadirachta indica), known for its secondary metabolites with biological activity against various insect groups of agricultural and public health importance. This study investigated the effects of a nanoformulation prototype Neem on factors linked to the vector competence of Anopheles aquasalis, a malaria vector in Latin America. Different concentrations of the nanoformulation were supplied through sugar solution and blood feeding, assessing impacts on longevity, fecundity, fertility, and transgenerational survival from larvae to adults. Additionally, the effects of the Neem nanoformulation and NeemAZAL® formulation on the sporogonic cycle of P. vivax were evaluated. Overall, significant impacts were observed at 100 ppm and 1,000 ppm concentrations on adult survival patterns and on survival of the F1 generation. A trend of reduced oviposition and hatching rates was also noted in nanoformulation-consuming groups, with fertility and fecundity declining proportionally to the concentration. Additionally, a significant decrease in the infection rate and intensity of P. vivax was observed in the 1,000 ppm group, with a mean of 3 oocysts per female compared to the control's 27 oocysts per female. In the commercial formulation, the highest tested concentration of 3 ppm yielded 5.36 oocysts per female. Concerning sporozoite numbers, there was a reduction of 52 % and 87 % at the highest concentrations compared to the control group. In conclusion, these findings suggest that the A. indica nanoformulation is a potential as a tool for malaria control through reduction in the vector longevity and reproductive capacity, possibly leading to decreased vector population densities. Moreover, the nanoformulation interfered with the sporogonic development of P. vivax. However, further basic research on Neem formulations, their effects, and mechanisms of action is imperative to gain a more specific perspective for safe field implementation.

2.
J Med Virol ; 96(3): e29529, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38516764

RESUMO

Studies on the impact of the COVID-19 pandemic in sub-Saharan Africa have yielded varying results, although authors universally agree the real burden surpasses reported cases. The primary objective of this study was to determine SARS-CoV-2 seroprevalence among patients attending Monkole Hospital in Kinshasa (D.R. Congo). The secondary objective was to evaluate the analytic performance of two chemiluminescence platforms: Elecsys® (Roche) and VirClia® (Vircell) on dried blood spot samples (DBS). The study population (N = 373) was recruited in two stages: a mid-2021 blood donor cohort (15.5% women) and a mid-2022 women cohort. Crude global seroprevalence was 61% (53.9%-67.8%) pre-Delta in 2021 and 90.2% (84.7%-94.2%) post-Omicron in 2022. Anti-spike (S) antibody levels significantly increased from 53.1 (31.8-131.3) U/mL in 2021 to 436.5 (219.3-950.5) U/mL in 2022 and were significantly higher above 45 years old in the 2022 population. Both platforms showed good analytic performance on DBS samples: sensitivity was 96.8% for IgG (antiN/S) (93.9%-98.5%) and 96.0% (93.0%-98.0%) for anti-S quantification. These results provide additional support for the notion that exposure to SARS-CoV-2 is more widespread than indicated by case-based surveillance and will be able to guide the pandemic response and strategy moving forward. Likewise, this study contributes evidence to the reliability of DBS as a tool for serological testing and diagnosis in resource-limited settings.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Feminino , Pessoa de Meia-Idade , Masculino , COVID-19/diagnóstico , COVID-19/epidemiologia , República Democrática do Congo/epidemiologia , Pandemias , Reprodutibilidade dos Testes , Estudos Soroepidemiológicos , Anticorpos Antivirais
3.
Diagnostics (Basel) ; 13(3)2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36766454

RESUMO

Dried blood spots (DBSs) are an economical and convenient alternative to serum/plasma, which allow for the serological and molecular study of different pathogens. Sixty-four blood samples were collected by venipuncture and spotted onto Whatman™ 903 cards to evaluate the utility of DBSs and the effect of the storage temperature for 120 days after sample collection to carry out serological diagnosis. Mumps, measles and rubella IgG were investigated from DBSs and plasma using an automated chemiluminescent immunoassay. Using a calculated optimal cut-off value, the serological evaluation of mumps, measles and rubella using DBSs achieved high sensitivity (100%, 100% and 82.5%, respectively) and specificity (100%, 87.5% and 100%, respectively). The correlation observed between the plasma and the DBSs processed after sample collection was high (0.914-0.953) for all antibodies studied, both considering hematocrit before sample elution or not. For the different storage conditions, the correlation with plasma was high at 4 °C (0.889-0.925) and at -20 °C (0.878-0.951) but lower at room temperature (0.762-0.872). Measles IgG results were more affected than other markers when DBSs were stored at any temperature for 120 days. To summarize, hematocrit does not affect the processing of DBSs in the study of serological markers of mumps, measles and rubella. DBS stability for serological diagnosis of mumps and rubella is adequate when samples are stored at -20 °C or 4 °C, but not at room temperature, for a period of 4 months.

4.
Addict Behav Rep ; 14: 100389, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34938847

RESUMO

INTRODUCTION: Use of Social networking sites (SNSs) is a highly prevalent behavior worldwide and, for some individuals, its use can turn maladaptive. There has been growing interest to identify which variables are associated with problematic use of SNSs. AIM: The present study cross-sectionally examined whether the associations between different features of self-control (i.e., impulsivity-like traits, self-regulation and emotion regulation) indirectly relate to two outcomes of SNSs (hours of use and problematic use) via distress tolerance. METHODS: A sample of 509 Argentinean college students (70.3% female; Mean age = 21.15 ± 5.15) completed an online survey. RESULTS: Two significant indirect effects were found: a) higher negative urgency was associated with higher problematic use of SNSs via lower distress tolerance and b) higher self-regulation was associated with lower problematic use of SNSs via higher distress tolerance. Positive urgency, negative urgency and self-regulation had significant direct associations with problematic use of SNSs while neither component of emotion regulation was significantly associated with SNSs outcomes. No significant direct or indirect effects were found between any of the self-control features and time spent using SNSs. CONCLUSIONS: The results highlight dysfunctional self-control, particularly emotion-driven impulsivity and low self-regulation, as relevant components of maladaptive SNSs that seem to operate by decreasing the perceived capacity to tolerate negative affect. In this context, interventions targeting the development and improvement of distress tolerance abilities might have a positive impact on problematic use of SNS.

5.
Eur J Clin Microbiol Infect Dis ; 40(6): 1343-1349, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33512616

RESUMO

AIM: To evaluate the serological response against SARS-CoV-2 in a multicenter study representative of the Spanish COVID pandemic. METHODS: IgG and IgM + IgA responses were measured on 1466 samples from 1236 Spanish COVID-19 patients admitted to the hospital, two commercial ELISA kits (Vircell SL, Spain) based on the detection of antibodies against the viral spike protein and nucleoprotein, were used. RESULTS: Approximately half of the patients presented antibodies (56.8% were IgM + IgA positive and 43.0% were IgG positive) as soon as 2 days after the first positive PCR result. Serological test positivity increased with time from the PCR test, and 10 days after the first PCR result, 91.5% and 88.0% of the patients presented IgM + IgA and IgG antibodies, respectively. CONCLUSION: The high values of sensitivity attained in the present study from a relatively early period of time after hospitalization support the use of the evaluated serological assays as supplementary diagnostic tests for the clinical management of COVID-19.


Assuntos
Anticorpos Antivirais/sangue , Formação de Anticorpos , COVID-19/imunologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Teste Sorológico para COVID-19 , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Hospitalização , Humanos , Imunoglobulina A , Imunoglobulina G , Imunoglobulina M , Masculino , Pessoa de Meia-Idade , Fosfoproteínas/imunologia , Sensibilidade e Especificidade , Fatores Sexuais , Espanha , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto Jovem
6.
J Clin Microbiol ; 59(2)2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-33127841

RESUMO

Reliable serological tests are required to determine the prevalence of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to characterize immunity to the disease in order to address key knowledge gaps in the coronavirus disease 2019 (COVID-19) pandemic. Quantitative suspension array technology (qSAT) assays based on the xMAP Luminex platform overcome the limitations of rapid diagnostic tests and enzyme-linked immunosorbent assays (ELISAs) with their higher precision, dynamic range, throughput, miniaturization, cost-efficiency, and multiplexing capacity. We developed three qSAT assays for IgM, IgA, and IgG against a panel of eight SARS-CoV-2 antigens, including spike protein (S), nucleocapsid protein (N), and membrane protein (M) constructs. The assays were optimized to minimize the processing time and maximize the signal-to-noise ratio. We evaluated their performances using 128 prepandemic plasma samples (negative controls) and 104 plasma samples from individuals with SARS-CoV-2 diagnosis (positive controls), of whom 5 were asymptomatic, 51 had mild symptoms, and 48 were hospitalized. Preexisting IgG antibodies recognizing N, M, and S proteins were detected in negative controls, which is suggestive of cross-reactivity to common-cold coronaviruses. The best-performing antibody/antigen signatures had specificities of 100% and sensitivities of 95.78% at ≥14 days and 95.65% at ≥21 days since the onset of symptoms, with areas under the curve (AUCs) of 0.977 and 0.999, respectively. Combining multiple markers as assessed by qSAT assays has the highest efficiency, breadth, and versatility to accurately detect low-level antibody responses for obtaining reliable data on the prevalence of exposure to novel pathogens in a population. Our assays will allow gaining insights into antibody correlates of immunity and their kinetics, required for vaccine development to combat the COVID-19 pandemic.


Assuntos
Antígenos Virais/imunologia , Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , Isotipos de Imunoglobulinas/sangue , SARS-CoV-2/imunologia , Adulto , Anticorpos Antivirais/sangue , COVID-19/sangue , Reações Cruzadas , Feminino , Humanos , Imunoensaio , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Proteínas Estruturais Virais/imunologia
7.
Environ Sci Pollut Res Int ; 28(19): 23791-23811, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33140298

RESUMO

Advanced oxidation processes (AOPs) constitute a developing area of particular interest for researchers in different fields due to their broad range of applications. However, there are few studies dedicated to the bibliometric analysis of AOPs. Hence, a systematic literature review of research publications (research articles, review articles, and book chapters) from 1980 to 2018 was carried out to visualize and evaluate research trends on AOPs around the world and, especially in Ibero-America (IA), on the field of wastewater treatment. Using the most extensive databases in literature search, Scopus and Web of Science (WoS), which encompass 95% of the publications in the world, a total of 18,751 records were retrieved by limiting the search results to words associated with AOPs in the titles, keyword, and abstracts. Raw data were manually organized and filtered, standardizing authors and institution names, publication titles, and keywords for the purpose of eliminating double-counted entries. Similarly, homonymous authors and institutions were identified for all records retrieved. The bibliometric dataset was processed using the VantagePoint software. The research trends visualized about AOPs were as follows: number of publications per triennium, publications by country, participation by continent, most important journals and authors, most referenced institutions, global network of co-authors, and keywords network visualization, highlighting the Ibero-American contribution to global research.


Assuntos
Bibliometria , Águas Residuárias , Bases de Dados Factuais , Oxirredução , Estados Unidos
8.
Blood ; 135(26): 2375-2387, 2020 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-32299093

RESUMO

Risk of developing myelodysplastic syndrome (MDS) is significantly increased in both multiple myeloma (MM) and monoclonal gammopathy of undetermined significance, suggesting that it is therapy independent. However, the incidence and sequelae of dysplastic hematopoiesis at diagnosis are unknown. Here, we used multidimensional flow cytometry (MFC) to prospectively screen for the presence of MDS-associated phenotypic alterations (MDS-PA) in the bone marrow of 285 patients with MM enrolled in the PETHEMA/GEM2012MENOS65 trial (#NCT01916252). We investigated the clinical significance of monocytic MDS-PA in a larger series of 1252 patients enrolled in 4 PETHEMA/GEM protocols. At diagnosis, 33 (11.6%) of 285 cases displayed MDS-PA. Bulk and single-cell-targeted sequencing of MDS recurrently mutated genes in CD34+ progenitors (and dysplastic lineages) from 67 patients revealed clonal hematopoiesis in 13 (50%) of 26 cases with MDS-PA vs 9 (22%) of 41 without MDS-PA; TET2 and NRAS were the most frequently mutated genes. Dynamics of MDS-PA at diagnosis and after autologous transplant were evaluated in 86 of 285 patients and showed that in most cases (69 of 86 [80%]), MDS-PA either persisted or remained absent in patients with or without MDS-PA at diagnosis, respectively. Noteworthy, MDS-associated mutations infrequently emerged after high-dose therapy. Based on MFC profiling, patients with MDS-PA have altered hematopoiesis and T regulatory cell distribution in the tumor microenvironment. Importantly, the presence of monocytic MDS-PA at diagnosis anticipated greater risk of hematologic toxicity and was independently associated with inferior progression-free survival (hazard ratio, 1.5; P = .02) and overall survival (hazard ratio, 1.7; P = .01). This study reveals the biological and clinical significance of dysplastic hematopoiesis in newly diagnosed MM, which can be screened with moderate sensitivity using cost-effective MFC.


Assuntos
Hematopoiese Clonal , Mieloma Múltiplo/patologia , Síndromes Mielodisplásicas/etiologia , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Ensaios Clínicos Fase III como Assunto , Terapia Combinada , Feminino , Citometria de Fluxo/métodos , Transplante de Células-Tronco Hematopoéticas , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Hibridização in Situ Fluorescente , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/mortalidade , Mieloma Múltiplo/terapia , Mutação , Prognóstico , Intervalo Livre de Progressão , Estudos Prospectivos , Ensaios Clínicos Controlados Aleatórios como Assunto , Transplante Autólogo , Microambiente Tumoral
9.
PLoS One ; 14(12): e0225833, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31790474

RESUMO

The understanding of factors affecting the gut bacterial communities in malaria vectors is essential for the design of vector control interventions, such as those based on a paratransgenic approach. One of the requirements of this method is the availability of bacteria from the mosquito susceptible to culture. Thus, the aim of this study was to evaluate the composition and structure of the culturable gut bacterial communities in field mosquitoes Anopheles albimanus from Colombia, in addition to generate a bacterial collection to further analyze microbial functional activity. Gut bacteria were isolated from An. albimanus larvae and adult mosquitoes collected in localities of the Atlantic and Pacific Coasts. The bacterial isolates were grouped in 28 morphospecies that corresponded to three phyla, three classes, nine families and 14 genera. The larvae guts from San Antero (Atlantic Coast) and Buenaventura (Pacific Coast) shared the genera Bacillus and Lysinibacillus and in adults, Bacillus and Bacillus cereus Group were registered in both localities. Gut bacterial richness was higher in adults from the Pacific with respect to the Atlantic Coast, while larval richness was similar in samples of both coasts. The Shannon index indicated uniformity in morphospecies abundances in both localities. Finally, the characterization of morphospecies from the gut of Anopheles albimanus mosquitoes from Colombia by culture-dependent methods complemented with 16S rRNA gene sequencing allowed the definition, at a finer resolution, of the composition and structure of these microbial communities. In addition, the obtained bacterial culture collection will allow further evaluation of the microorganisms for their potential as biocontrol agents.


Assuntos
Anopheles/microbiologia , Bactérias/crescimento & desenvolvimento , Microbioma Gastrointestinal , Algoritmos , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Sequência de Bases , Teorema de Bayes , Biodiversidade , Colômbia , Resistência Microbiana a Medicamentos , Geografia , Larva/microbiologia , Filogenia , RNA Ribossômico 16S/genética
10.
Phys Rev Lett ; 107(2): 021301, 2011 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-21797590

RESUMO

We report the first detection of the gravitational lensing of the cosmic microwave background through a measurement of the four-point correlation function in the temperature maps made by the Atacama Cosmology Telescope. We verify our detection by calculating the levels of potential contaminants and performing a number of null tests. The resulting convergence power spectrum at 2° angular scales measures the amplitude of matter density fluctuations on comoving length scales of around 100 Mpc at redshifts around 0.5 to 3. The measured amplitude of the signal agrees with Lambda cold dark matter cosmology predictions. Since the amplitude of the convergence power spectrum scales as the square of the amplitude of the density fluctuations, the 4σ detection of the lensing signal measures the amplitude of density fluctuations to 12%.

11.
Medicina (Guayaquil) ; 11(1): 33-36, abr. 2006.
Artigo em Espanhol | LILACS | ID: lil-652420

RESUMO

Tipo de Estudio: Descriptivo epidemiológico retrospectivo en 644 pacientes ingresados en la Unidad de quemados del hospital “Luis Vernaza” período 2003. Objetivos: Ordenar y presentar la información obtenida en el manejo de las quemaduras por electricidad en esta unidad especializada. Resultados: Pacientes de sexo masculino 86.80%, 59.47%, con edades entre 21 y 40 años. El sitio con mayor ocurrencia de accidentes fue el lugar de trabajo con 351 (54.50%) reportes, en el hogar se produjeron 236 (36.65%) casos, 57 (8.85%) en la calle, automóvil, etc. Generalmente los pacientes presentaron quemaduras de II grado con una media de 9.3% de Superficie Corporal Quemada (SCQ). La secuela más importante fue la amputación; 64.3% de éstas se realizaron en miembros superiores. La estancia hospitalaria media fue de 38 días, la mortalidad 3.1%. Conclusiones: La tendencia del número de casos con quemaduras eléctricas atendidos en el hospital “Luis Vernaza” está elevándose y es importante el grado de discapacidad que producen, lo que puede significar para los sistemas de salud una significativa inversión de recursos.


Type of study: Descriptive, retrospective of 644 patients admitted to the Burn Unit of the “Luis Vernaza” Hospital period 2003.Objectives: To organize the information obtained in managing electrical burn injuries admitted to the unit.Results:We found that electrical burn injuries were most common in males (86.80%) between the age group of 21-40 (59.47%). Percentage of the most common places of injury was:•Place of work – 351 (54.50%)•Household – 236 (36.65%)•Street, automobile, etc 57 cases (8.85%)Most of the patients had 2nd degree burns and a mean burn size of 9.3% total body surface area. The most common sequelae were amputation (64.3%) of superior limbs. The mean hospital stay was of 38 days and a mortality of 3.1%.Conclusions: The number of cases of electrical burn injuries admitted at the Hospital “Luis Vernaza” and rate of disability is increasing.


Assuntos
Masculino , Adulto , Feminino , Pessoa de Meia-Idade , Acidentes de Trabalho , Queimaduras por Corrente Elétrica , Unidades de Queimados , Hidratação , Riscos Ocupacionais
12.
Artigo em Inglês | MEDLINE | ID: mdl-15921294

RESUMO

The objective of this article is to evaluate the effect of water depth on organic matter removal efficiency in horizontal subsurface flow constructed wetlands (SSFs). Experiments were carried out in a pilot plant comprising eight parallel SSF of almost equal surface area (54-56 m2 each) and treating urban wastewater. Each SSF differs from the others in the aspect ratio or the size of the granular medium or the water depth. During a period of two years, the shallow SSFs (0.27 m water depth) removed more chemical oxygen demand (COD) (72-81%), biochemical oxygen demand (BOD)5 (72-85%), ammonia (35-56%), and dissolved reactive phosphorus (DRP) (8-23%) than deep SSFs (0.5 m water depth) (59-64% for COD; 51-57% for BOD5; 18-29% for ammonia; and 0-7% for DRP). Experiments carried out during the summer indicated that sulphate reduction accounted for a clearly higher organic matter removal in the deep SSFs than in the shallow ones. Denitrification seemed to be a significant mechanism for organic matter removal to occur in shallow SSFs. The results suggest that the relative contribution of different metabolic pathways varies with depth.


Assuntos
Ecossistema , Nitrogênio/metabolismo , Eliminação de Resíduos Líquidos/métodos , Compostos Orgânicos , Oxigênio/metabolismo , Fósforo/análise , Fósforo/química , Plantas , Estações do Ano , Movimentos da Água
13.
Chemosphere ; 59(6): 769-77, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15811405

RESUMO

A pilot-scale horizontal flow constructed wetland (HFCW) system planted with common reed (Phragmites sp.) was constructed to study how hydraulic loading rate (HLR), aspect ratio, water depth, and granular medium affect to the fate of several organic matter degradation intermediates namely, acetic acid (HAc), isovaleric acid (Isoval), and dimethylsulfide (DMS). ANOVA statistical analysis performed on the data set of 8 months of operation shows that the HLR and the water depth are two major factors that control the performance of HFCWs for the target analytes. A clear difference in the HFCW effluent concentrations was obtained according to water depth. Effluents of the shallow water depth contained lower DMS (1.05-1.44 microg l-1), HAc (7.91-10.9 mg l-1), and Isoval (0.11-0.15 mg l-1) concentrations than the deeper beds (DMS: 1.68-2.40 microg l-1; HAc: 9.29-14.4 mg l-1, and Isoval: 0.20-0.31 mg l-1). Such differences could be accounted to the different formation and consumption rates of the organic matter degradation intermediates, which is related with the redox potentials (E). Indeed, it could lead to different biochemical reactions of organic matter degradation according with the E value. HLR has a statistically significant influence on the effluent HAc, Isoval, and DMS concentrations. Seasonal variability of effluent HAc concentration shows that it is independent on the HAc loading. While the loading showed no seasonal pattern, the removal efficiency was clearly higher in cold months, which suggests a predominant internal production of HAc in HFCWs in the warm season from the accumulated organic particulate matter. Similar results were also found when Isoval and DMS were considered.


Assuntos
Acetatos/análise , Ácidos Pentanoicos/análise , Sulfetos/análise , Eliminação de Resíduos Líquidos/métodos , Acetatos/metabolismo , Biodegradação Ambiental , Hemiterpenos , Ácidos Pentanoicos/metabolismo , Poaceae , Sulfetos/metabolismo , Movimentos da Água
14.
Environ Sci Technol ; 38(9): 2657-63, 2004 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-15180062

RESUMO

The behavior of linear alkylbenzene sulfonate (LAS) and sulfophenyl carboxylate (SPC) biointermediates in a pilot subsurface flow constructed wetland (SFCW) is reported for the first time. The effects of wetland configuration and operation on their treatment efficiency were investigated. The pilot SFCW constituted by eight beds of 55 m2 with different aspect ratios (1 x 1; 1.5 x 1; 2 x 1; 2.5 x 1), two water depths (i.e., 0.47 and 0.27 cm) at 5 cm below surface and two medium sizes (i.e., D60 = 10 mm and 3.5 mm) planted with Phragmites sp. That SFCW pilottreats urban wastewater (i.e., 200 inhabitants) and was operated at four hydraulic loading rates (HLRs) (20, 27, 36, and 45 mm d(-1)). Influent and effluent sampling was carried out from May 2001 to January 2002 with a weekly pattern. Main results were as follows: (i) water depth has a major influence on the performance of SFCW for the LAS removal, and HLR shows significant effect on SPC evolution; (ii) water temperature has a significant effect on the LAS evolution; (iii) biodegradation of LAS and SPC can occur under sulfate-reducing environment and mixed conditions (i.e., sulfate-reducing and denitrification), but aerobic respiration cannot be excluded; and (iv) C13 LAS homologues were generally removed in higher extent than the shorter alkyl chain counterparts. In the most appropriate conditions, LAS and SPC can be biodegraded up to 71% and 11%, respectively, in the pilot SFCW evaluated.


Assuntos
Ácidos Alcanossulfônicos/isolamento & purificação , Tensoativos/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Ácidos Alcanossulfônicos/metabolismo , Biodegradação Ambiental , Ecossistema , Poaceae , Tensoativos/metabolismo , Movimentos da Água , Poluentes Químicos da Água/metabolismo
15.
Water Res ; 38(7): 1669-78, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15026221

RESUMO

This study evaluates the effect of hydraulic loading rate (HLR), aspect ratio, granular medium size and water depth on the removal of selected contaminants during the start up of horizontal subsurface flow reed beds (HFRBs). Experiments were carried out in a pilot-scale HFRB system comprising four pairs of lined beds of almost equal surface area (54-56 m(2) each bed), with the following aspect ratios: 1:1, 1.5:1, 2:1 and 2.5:1. The size of the granular medium of each pair varied from coarse granitic gravel ( D(60) = 10mm, C(u) = 1.6) to small granitic gravel (D(60) = 3.5 mm, C(u) = 1.7). The beds of the pair with longest aspect ratio were made shallower (0.27 m) than the rest (0.5m) The system was sampled weekly from May 2001 to January 2002. The results indicate that HLR and water depth are determining factors in the performance of the HFRBs. Beds with a water depth of 0.27 m removed more COD (70-80%), BOD(5) (70-85%), ammonia (40-50%) and dissolved reactive phosphorus (DRP) (10-22%) than beds with a depth of 0.5m (60-65% for COD, 50-60% for BOD(5), 25-30% for ammonia, and 2-10% for DRP). The higher efficiency observed shallower beds was related to their less reducing conditions (average redox potential (E) ranging from -351 to -338 mV) than beds with a depth of 0.5m (-390 to -358 mV). The difference in E status between two bed types seems to lead to differences in the biochemical processes. In fact, denitrification was estimated to be a significant reaction in shallower beds.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Biodegradação Ambiental , Cidades , Ecossistema , Filtração , Nitrogênio/análise , Nitrogênio/isolamento & purificação , Oxigênio/análise , Fósforo/análise , Fósforo/isolamento & purificação , Plantas , Movimentos da Água
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