Effects of the Natural Flavonoid Quercetin on Arenavirus Junín Infection.

There is no specific chemotherapy approved for the treatment of pathogenic arenaviruses that cause severe hemorrhagic fever (HF) in the population of endemic regions in America and Africa. The present study reports the effects of the natural flavonoid quercetin (QUER) on the infection of A549 and Vero cells with Junín virus (JUNV), agent of the Argentine HF. By infectivity assays, a very effective dose-dependent reduction of JUNV multiplication was shown by cell pretreatment at 2-6 h prior to the infection at non-cytotoxic concentrations, with 50% effective concentration values in the range of 6.1-7.5 µg/mL. QUER was also active by post-infection treatment but with minor efficacy. Mechanistic studies indicated that QUER mainly affected the early steps of virus adsorption and internalization in the multiplication cycle of JUNV. Treatment with QUER blocked the phosphorylation of Akt without changes in the total protein expression, detected by Western blot, and the consequent perturbation of the PI3K/Akt pathway was also associated with the fluorescence redistribution from membrane to cytoplasm of TfR1, the cell receptor recognized by JUNV. Then, it appears that the cellular antiviral state, induced by QUER treatment, leads to the prevention of JUNV entry into the cell.

Modulation of the Aryl Hydrocarbon Receptor Signaling Pathway Impacts on Junín Virus Replication.

Junín virus (JUNV), a member of the family Arenaviridae, is the etiological agent of the Argentine hemorrhagic fever, an endemic disease in the rural region of Argentina lacking a specific chemotherapy. Aryl hydrocarbon receptor (AHR) is expressed in several mammalian tissues and has been indicated as a sensor of ligands from variable sources and a modulator of the cell immune response. Interestingly, recent studies have suggested that the activation or depression of the AHR signaling pathway may play a role in the outcome of diverse human viral infections. In the present report, the effect of the pharmacological modulation of AHR on JUNV in vitro infection was analyzed. An initial microarray screening showed that the AHR pathway was overexpressed in JUNV-infected hepatic cells. Concomitantly, the infection of Vero and Huh-7 cells with the JUNV strains IV4454 and Candid#1 was significantly inhibited in a dose-dependent manner by treatment with CH223191, a specific AHR antagonist, as detected by infectivity assays, real-time RT-PCR and immunofluorescence detection of viral proteins. Furthermore, the pro-viral role of AHR in JUNV infection appears to be independent of the IFN-I pathway. Our findings support the promising perspectives of the pharmacological modulation of AHR as a potential target for the control of AHF.

Estimating Neonatal Necrotizing Enterocolitis Based on Feeding Practices.

(1) Background: The relationship between enteral nutrition and neonatal necrotizing enterocolitis (NEC) among premature neonates is still unclear. The present work was designed to assess the relationship between NEC and feeding strategies compared to control infants. (2) Methods: A retrospective case-control study of premature infants (<35 weeks' gestation) with or without NEC that examined feeding practices and clinical characteristics at birth and 3, 7, and 14-day hospitalization, with a longitudinal and cross-sectional analysis. (3) Results: A total of 100 newborns with NEC diagnosis and 92 neonates without the disease with similar demographic and clinical characteristics were included. The median day of NEC diagnosis was 15 days (Interquartile Range (IQR) 5-25 days). A significantly higher number of neonates that were fasting on days 7 and 14 developed NEC (p < 0.05). In the longitudinal analysis, generalized linear and mixed models were fit to evaluate NEC association with feeding strategies and showed that exclusive mother's own milk (MM) and fortified human milk (FHM) across time were significantly less likely associated with NEC (p < 0.001) and that enteral fasting was positively related with NEC. In the cross-sectional analysis, a binary logistic regression model was fit and predicted 80.7% of NEC cases. MM was also found to correlate with a reduced risk for NEC (OR 0.148, 95% CI 0.044-0.05, p = 0.02), and in particular, on day 14, several factors were related to a decreased odd for NEC, including birth weight, antenatal steroids, and the use of FHM (p < 0.001). (4) Conclusions: MM and FHM were associated with less NEC compared to fasting on days 7 and 14. Feeding practices in Neonatal Intensive Care Units (NICUs) should promote exclusive MM across the two-week critical period as a potential guideline to improve NEC outcome.

Procesos de vinculación, permanencia y reintegración social de niños y niñas que participaron en grupos armados ilegales en Colombia / Processes of Involvement, Permanence, and Social Reintegration of Children Who Participated in Illegal Armed Groups in Colombia

Resumen El presente trabajo tuvo como objetivo realizar una revisión de la literatura sobre los procesos de vinculación, permanencia y reintegración de niños y niñas que participaron en grupos armados ilegales de Colombia (gai). Se revisaron 51 documentos de bases de datos especializadas y catálogos de universidades colombianas en el periodo entre 2005 y 2018. Los resultados mostraron que la mayoría de los estudios realizados se concentran en los procesos de vinculación y reintegración. Se discuten diferentes perspectivas sobre la denominación de este grupo poblacional, se mencionan las causas identificadas para la vinculación, dinámicas de interacción y ajuste a los gaidurante la permanencia. Así mismo, se analizan las vivencias en los procesos de reintegración y características de los programas de atención y se presentan algunas recomendaciones para los procesos de reintegración.

Abstract The current work aimed to review the literature on the processes of involvement, permanence and reintegration of children who participated in illegal armed groups (iag) in Colombia. Fifty-one (51) documents of specialized databases and catalogs of Colombian universities were reviewed in the period between 2005 and 2018. The results showed that most of the studies on the participation of children in armed groups are focused on the processes of involvement and reintegration. Different perspectives on the denomination of this population group are discussed, as well as the causes identified for the involvement and the dynamics of interaction and adjustment to the iagduring the stay. Besides, the experiences involved during the reintegration processes were analyzed and the characteristics of the care programs are mentioned. Finally, some recommendations for the reintegration process are presented.

Panuveítis asociada a la enfermedad de Lyme en un paciente colombiano. Reporte de caso / Panuveitis due to Lyme disease in a Colombian patient: Case report

RESUMEN La enfermedad de Lyme es una zoonosis transmitida por la picadura de garrapatas del género Ixodes sp. Ha sido descrita con más frecuencia en zonas endémicas de países meridionales. Sus manifestaciones clínicas son muy variables y se presentan de acuerdo con el estadio clínico de la enfermedad, teniendo así el compromiso ocular un espectro clínico muy variado que incluye manifestaciones desde la superficie ocular hasta la inflamación del segmento posterior. Se presenta el caso de un paciente de 72 años con un viaje reciente a los Estados Unidos (EE. UU.), atendido en la consulta particular por un oftalmólogo supraespecialista en uveítis de la ciudad de Medellín. El paciente hacía un mes refería una disminución de la agudeza visual (AV) en su ojo izquierdo y al examen oftalmológico presentó signos clínicos de panuveítis no granulomatosa asociada a un edema macular y vasculitis retinal. Se confirmó la enfermedad de Lyme en fase tardía por la presencia de anticuerpos en sangre por Western blot. Se realizó tratamiento exitoso con antibióticos (doxiciclina), con recuperación de la AV y la mejoría completa de los signos inflamatorios intraoculares.

SUMMARY Lyme Disease is a zoonosis transmitted by arthropods that has been described with more frequency in endemic zones of meridional countries. Its clinical manifestations vary according to the clinical stage of the disease. The eye can be affected in many forms including the involvement of the ocular surface and the posterior segment, with more severe inflammation of the retina and the choroid. We present a case of a 72-year male with a recent trip to EEUU who complained of decreasing vision in his left eye had clinical signs of non-granulomatous panuveitis with macular edema and retinal vasculitis. Lyme disease was confirmed with positive antibodies in blood and Western blot test, and the patient was successfully treated using oral Doxycycline. His visual acuity improved and had a resolution of the intraocular inflammation after the specific treatment.

C-reactive protein (CRP) polymorphisms and haplotypes are associated with SLE susceptibility and activity but not with serum CRP levels in Mexican population.

To evaluate the association of C-reactive protein (CRP) polymorphisms with risk of development SLE in a group of Mexican individuals. Five CRP polymorphisms (rs3093059, rs3093062, rs1800947, rs1130864, and rs1205) were determined by PCR-restriction fragment length polymorphism and SNP rs3093061 by refractory mutation system PCR assay in 126 SLE patients and 131 controls. Four of the polymorphisms showed differences between patients and controls. rs3093061 polymorphism was associated with a lower risk of developing lupus principally in the codominant 2 (OR = 0.219, 95% CI 0.108-0.785, P = 0.015) model. rs1130864 was associated with decreased risk mainly under codominant 1 (OR = 0.288, 95% CI 0.143-0.581, P = 0.001) model. rs1205 was associated under the over-dominant model (OR = 0.504, 95% CI 0.270-0.942, P = 0.032). The rs3091244 polymorphism was associated with decreased risk of SLE mostly under additive (OR = 0.605, 95% CI 0.393-0.931. P = 0.022) model. Our study establishes that rs3093061, rs1130864, rs1205, and rs3091244 polymorphisms are associated with decreased risk of developing SLE.

Environment, trauma and technical innovations: Three links between Donald W. Winnicott and Sándor Ferenczi / Ambiente, trauma e innovaciones técnicas: tres articulaciones entre Donald W. Winnicott y Sándor Ferenczi

Abstract Throughout this paper, the theoretical and clinical approaches of D.W. Winnicott are reviewed in order to reread the written production of Sándor Ferenczi. Winnicott's clinical and theoretical concepts allow returning to Ferenczi and rescuing aspects of his work that had been silenced in the psychoanalytic community. Ferenczi, in turn, is one that holds his presence in Winnicott's thought. Even though there are few times in which he cites Ferenczi in his work, it is possible to draw clear relationships between both theories. Three main issues are addressed: the role of the environment as active; the primitive traumatic event in which there is no one that has experience of it, and psychoanalysis as the place to experience that which happened in the first months of life for the first time; and, finally, severe pathologies and psychoses: technical innovations in Winnicott and Ferenczi for the treatment of psychotic and borderline patients. It is concluded that the theoretical and technical developments of Winnicott serve to illuminate a retrospective reading of Ferenczi.

Resumen A través de este trabajo, se retoman los planteamientos teóricos y clínicos de D.W. Winnicott para releer la producción escrita de Sándor Ferenczi. Los conceptos teóricos y clínicos de Winnicott permiten volver a Ferenczi y rescatar aspectos de su obra que habían quedado silenciados en la comunidad psicoanalítica. Ferenczi, a su vez, conserva su presencia en limítrofe el pensamiento de Winnicott. Si bien son escasas las veces que cita a Ferenczi en su obra, es posible trazar claros puntos de encuentro entre ambas teorías. Se abordan tres puntos principales: el papel del medio como activo, la vivencia traumática primitiva en la cual no hay un alguien que haga experiencia de ello y el psicoanálisis como el lugar para hacer experiencia por primera vez de eso que ocurrió en los primeros meses de vida y, por último, las enfermedades graves y la psicosis: innovaciones técnicas en Winnicott y Ferenczi para el tratamiento de pacientes psicóticos y borderline. Se concluye que los desarrollos teóricos y técnicos de Winnicott sirven para iluminar una lectura retrospectiva de Ferenczi.

[Environment, Trauma and Technical Innovations: Three Links Between Donald W. Winnicott and Sándor Ferenczi]. / Ambiente, trauma e innovaciones técnicas: tres articulaciones entre Donald W. Winnicott y Sándor Ferenczi.

Throughout this paper, the theoretical and clinical approaches of D.W. Winnicott are reviewed in order to reread the written production of Sándor Ferenczi. Winnicott's clinical and theoretical concepts allow returning to Ferenczi and rescuing aspects of his work that had been silenced in the psychoanalytic community. Ferenczi, in turn, is one that holds his presence in Winnicott's thought. Even though there are few times in which he cites Ferenczi in his work, it is possible to draw clear relationships between both theories. Three main issues are addressed: the role of the environment as active; the primitive traumatic event in which there is no one that has experience of it, and psychoanalysis as the place to experience that which happened in the first months of life for the first time; and, finally, severe pathologies and psychoses: technical innovations in Winnicott and Ferenczi for the treatment of psychotic and borderline patients. It is concluded that the theoretical and technical developments of Winnicott serve to illuminate a retrospective reading of Ferenczi.

Rheumatoid Arthritis Disease Activity Is Determinant for ABCB1 and ABCG2 Drug-Efflux Transporters Function.

OBJECTIVE: To compare drug efflux function of ABCB1 and ABCG2 transporters in rheumatoid arthritis (RA) patients with active disease and in remission. METHODS: Twenty two active RA patients (DAS28 ≥3.2) and 22 patients in remission (DAS28<2.6) were selected from an early RA clinic. All patients were evaluated at study inclusion and six months later. ABCB1 and ABCG2 functional activity was measured in peripheral lymphocytes by flow cytometry. The percentage of cells able to extrude substrates for ABCB1 and ABCG2 was recorded. RESULTS: Active patients had higher ABCB1 and ABCG2 activity compared with patients in remission (median [interquartile range]): 3.9% (1.4-22.2) vs (1.3% (0.6-3.2), p = 0.003 and 3.9% (1.1-13.3) vs 0.9% (0.5-1.9) p = 0.006 respectively. Both transporters correlated with disease activity assessed by DAS28, rho = 0.45, p = 0.002 and rho = 0.47, p = 0.001 respectively. Correlation was observed between the time from the beginning of treatment and transporter activity: rho = 0.34, p = 0.025 for ABCB1 and rho = 0.35, p = 0.018 for ABCG2. The linear regression model showed that DAS28 and the time from the onset of treatment are predictors of ABCB1 and ABCG2 functional activity, even after adjustment for treatment. After six months we calculated the correlation between change in DAS28 and change in the functional activity in both transporters and found a moderate and significant correlation for ABCG2 (rho = 0.28, p = 0.04) and a non-significant correlation for ABCB1 (rho = 0.22, p = 0.11). CONCLUSIONS: Patients with active RA have an increased function of ABCB1 and ABCG2, and disease activity is the main determinant of this phenomena.

Endoftalmitis endógena asociada a absceso hepático por Klebsiella pneumoniae. Descripción de tres casos y revisión de la literatura / Endoftalmite endógena associadas com abscesso hepático por Klebsiella Pneumoniae. Descrição de três casos e revisão de literatura / Endogenous endophthalmitis associated with Klebsiella pneumoniae liver abscess. Description of three cases and literature review

Se presentan los casos de tres pacientes con endoftalmitis endógena asociada a absceso hepático por Klebsiella pneumoniae, atendidos en el Hospital Universitario San Vicente Fundación, de Medellín. Esta complicación forma parte del síndrome de absceso hepático criptogénico invasor por K. pneumoniae, entidad descrita hace 25 años y cuya prevalencia parece ir en aumento. Para cada paciente se describen los síntomas y signos, el aislamiento microbiológico, el tratamiento, la evolución y el desenlace visual. Es la primera vez que se informa esta enfermedad en Colombia...

We describe three patients with endogenous endophthalmitis associated with Klebsiella pneumoniae liver abscess, treated at Hospital Universitario San Vicente Fundación (Medellín, Colombia). This complication is part of a syndrome described 25 years ago, whose prevalence seems to be rising: cryptogenic invasive K. pneumoniae liver abscess. Symptoms and signs, microbiological isolates, treatment, evolution and visual outcome are described for each patient.It is the first report of this disease in Colombia...

Apresenta o caso de três pacientes com endoftalmite endógena associadas com abscesso hepático por Klebsiella pneumoniae tratados no Hospital Universitário San Vicente Foundación, de Medellín. Esta complicação faz parte da síndrome, abscesso hepático criptogênica invasora por K. Pneumoniae, entidade descrita há 25 anos e cuja prevalência parece estar aumentando. Para cada paciente descreve os síntomas e sinais, o isolamento microbiológico, o tratamento, a evolução e o resultado visual. Esta é a primeira vez que se informa dessa doença na Colômbia...

Use of Selected Scavengers for the Determination of NF-TiO2 Reactive Oxygen Species during the Degradation of Microcystin-LR under Visible Light Irradiation.

Although UV-induced TiO2 photocatalysis involves the generation of several reactive oxygen species (ROS), the formation of hydroxyl radicals are generally associated with the degradation of persistent organic contaminants in water. In this study, a variety of radical scavengers were employed to discriminate the roles of different ROS during visible light activated (VLA) photocatalysis using nitrogen and fluorine doped TiO2 (NF-TiO2) in the degradation of the hepatotoxin, microcystin-LR (MC-LR) in water. The addition of hydroxyl radical scavengers, methanol and tert-butyl alcohol to the reaction mixture resulted in negligible inhibition of VLA NF-TiO2 photocatalytic degradation of MCLR at pH 3.0 and only partial inhibition at pH 5.7. While hydroxyl radicals generally play the primary role in UV TiO2 photocatalysis, the minimal influence of MeOH and t-BuOH on the degradation process under these experimental conditions indicates hydroxyl radicals (•OH) do not play the primary role in VLA NF-TiO2 photocatalysis. However, strong inhibition was observed in VLA NF-TiO2 photocatalytic degradation of MC-LR in the presence of superoxide dismutase, benzoquinone and catalase at pH 3.0 and 5.7 indicating O2•- and H2O2 play critical roles in the degradation process. Similar degradation rates were observed in the presence of singlet oxygen scavenger, deuterium oxide, which enhances singlet oxygen mediated processes further suggesting singlet oxygen does not play a key role in the degradation of MCLR in these system. Formic acid and cupric nitrate were added to probe the roles of the valence band holes and conduction band electrons, respectively. Under UV+vis light irradiation, almost complete inhibition of MC-LR removal is observed with NF-TiO2 in the presence of •OH scavengers at pH 5.7. These results demonstrate that solution pH plays a major role in the formation and reactivities of ROS during VLA NF-TiO2 photocatalysis. The adsorption strength of the scavengers and MCLR onto NF-TiO2 as well as the speciation of the ROS as a function of pH need to be carefully considered since they also play a key role in the efficiency of the process. These results indicate the reduction of molecular oxygen by photo-generated electrons rather than hydroxyl radicals produced by oxidative reactions of photo-generated holes play a key role in the of VLA NF-TiO2 photocatalytic degradation of MC-LR.

Main causes and risk factors for hospitalisation in patients with primary Sjögren's syndrome.

OBJECTIVES: To identify the causes and risk factors for hospitalisation in primary Sjögren's syndrome (pSS). METHODS: We included 170 pSS patients who regularly attended our Institution (2000-2013) and retrospectively collected demographic, clinical (glandular and extraglandular features) and serological (anti-Ro/SSA, anti-La/SSB, RF, low C3 or C4 and immunoglobulin levels) data. If they were hospitalised, a rheumatologist determined the primary cause. We registered the length of hospitalisation, need for Intensive Care Unit (ICU) admission, number of hospitalisations and death. The Disease Damage Index (SSDDI) (excluding the oral and ocular items) and the Charlson comorbidity Index were assessed. We used a logistic regression analysis and multiple imputation method for missing data. RESULTS: Fifty-five (32%) patients were hospitalised, representing 111 hospitalisations (28 patients had ≥1 hospital admission). The hospitalisation incidence density rate was 6.49/100 patient / years. The median length of hospital stay was 9 days (IQR 6-15), there were 7 ICU admissions and 6 deaths. The main causes of admissions were disease activity (33.3%) and infection (32.4%). At the multivariate analysis, the variables associated with hospitalisation were hepatic involvement (OR=5.4; 95% CI 1.61-18.15; p=0.006), vasculitis (OR=3.8; 95% CI 1.11-13.09; p=0.03), the SSDDI (OR=1.3; 95% CI 1.01-1.66; p=0.03) and the use of antimalarials (OR=0.08; 95% CI 0.02-0.22; p<0.001). CONCLUSIONS: The major causes for hospitalisation were disease activity and infection. Patients with hepatic involvement, vasculitis and more damage accrual had the highest risk for being hospitalised, while the use of antimalarials was protective.

El psicoanálisis de orientación lacaniana en el tratamiento del autismo / The psychoanalysis of lacanian orientation in the treatment of autism

El siguiente trabajo busca introducir los ejes principales del debate actual en torno al abordaje del autismo por parte del psicoanálisis lacaniano. Se retoman diversos escritos autobiográficos de autistas con el fin de desentrañar lo que ellos mismos pueden testimoniar respecto a aquello que les permitió una salida del repliegue autista. La investigación en la que se basa este texto enfatiza la importancia del reconocimiento que hace el psicoanálisis del autista como sujeto de pleno derecho y el papel fundamental que juega en los debates actuales sobre un tratamiento posible del autismo.

The following paper aims to introduce the main axes in the contemporary debate regarding the Lacanian psychoanalytic approach of autism. Different autobiographic writings by autistic people are here referred in order to untangle what they can bear witness to in relation to what allowed them a way out of their autistic withdrawal. The research on which this paper is based emphasizes the importance of the recognition that psychoanalysis makes of the autistic person as a subject with full rights and the fundamental role it plays in the contemporary debates regarding a possible treatment for autism.

Le texte suivant cherche à présenter les grands axes du débat actuel sur l'approche de la psychanalyse lacanienne dans l’étude de l'autisme. Divers récits autobiographiques d’autistes sont repris, afin d'élucider ce qu'eux-mêmes peuvent témoigner concernant ce que leur a permis la sortie du repli autistique. La recherche qui est à la base de ce texte met l'accent sur l'importance de la reconnaissance que fait la psychanalyse de l'autiste en tant que sujet de plein droit et le rôle fondamental que celle-ci joue dans les discussions actuelles sur un traitement possible de l'autisme.

Microcystin-LR removal from aqueous solutions using a magnetically separable N-doped TiO2 nanocomposite under visible light irradiation.

The performance of magnetically separable N-doped TiO2 was found to be significantly improved when compared with non-magnetic N-doped TiO2 for the removal of cyanotoxin microcystin-LR from aqueous medium. The observed enhanced photocatalytic activity may be related to the presence of ferrite nanoparticles in the composition of the magnetically separable composite N-doped TiO2.

A review on cylindrospermopsin: the global occurrence, detection, toxicity and degradation of a potent cyanotoxin.

Cylindrospermopsin is an important cyanobacterial toxin found in water bodies worldwide. The ever-increasing and global occurrence of massive and prolonged blooms of cylindrospermopsin-producing cyanobacteria poses a potential threat to both human and ecosystem health. Its toxicity is associated with metabolic activation and may involve mechanisms that adversely affect a wide variety of targets in an organism. Cylindrospermopsin has been shown to be cytotoxic, dermatotoxic, genotoxic, hepatotoxic in vivo, developmentally toxic, and may be carcinogenic. Human exposure may occur through drinking water, during recreational activities and by consuming foods in which the toxin may have bioaccumulated. Drinking water shortages of sufficient quality coupled with growing human pressures and climate variability and change necessitate an integrated and sustainable water management program. This review presents an overview of the importance of cylindrospermopsin, its detection, toxicity, worldwide distribution, and lastly, its chemical and biological degradation and removal by natural processes and drinking water treatment processes.

Photoinactivation of Escherichia coli by sulfur-doped and nitrogen-fluorine-codoped TiO2 nanoparticles under solar simulated light and visible light irradiation.

Titanium dioxide (TiO2) is one of the most widely used photocatalysts for the degradation of organic contaminants in water and air. Visible light (VL) activated sulfur-doped TiO2 (S-TiO2) and nitrogen-fluorine-codoped TiO2 (N-F-TiO2) were synthesized by sol-gel methods and characterized. Their photoinactivation performance was tested against Escherichia coli under solar simulated light (SSL) and VL irradiation with comparison to commercially available TiO2. Undoped Degussa-Evonik P-25 (P-25) and Sigma-TiO2 showed the highest photocatalytic activity toward E. coli inactivation under SSL irradiation, while S-TiO2 showed a moderate toxicity. After VL irradiation, Sigma-TiO2 showed higher photoinactivation, whereas S-TiO2 and P-25 showed moderate toxicity. Oxidative stress to E. coli occurred via formation of hydroxyl radicals leading to lipid peroxidation as the primary mechanism of bacterial inactivation. Various other biological models, including human keratinocytes (HaCaT), zebrafish liver cells (ZFL), and zebrafish embryos were also used to study the toxicity of TiO2 NPs. In conclusion, N-F-TiO2 did not show any toxicity based on the assay results from all the biological models used in this study, whereas S-TiO2 was toxic to zebrafish embryos under all the test conditions. These findings also demonstrate that the tested TiO2 nanoparticles do not show any adverse effects in HaCaT and ZFL cells.

NF-TiO2 photocatalysis of amitrole and atrazine with addition of oxidants under simulated solar light: emerging synergies, degradation intermediates, and reusable attributes.

In order to investigate sustainable alternatives to current water treatment methods, the effect of NF-titania film thickness and subsequent photocatalysis in combination with oxidants was examined under simulated solar light. Such a combination presents a theoretical possibility for a synergistic interaction between the photocatalyst and the oxidant (activation of the oxidant by the catalyst under conditions under which it may not conventionally be activated). To investigate, peroxymonosulfate (PMS) and persulfate (PS) were used as oxidants, and two pesticides, amitrole and atrazine, were used as target contaminants. In the absence of a film, activation of PMS under simulated solar conditions is demonstrated by removal of atrazine, whereas PS provided minimal removal, suggesting inefficient activation. Combining photocatalytic films with PMS and PS manifested synergies for both oxidants. The effect was most pronounced for PS since PMS already underwent significant activation without the photocatalyst. Amitrole degradation results indicated a lack of removal of amitrole by activated PS alone, suggesting that this sulfate radical-based treatment technology may be ineffective for the removal of amitrole. The NF-TiO2 films demonstrated reusability under solar light both with and without oxidants. Finally, the degradation intermediates were analyzed, and a new intermediate appeared upon incorporating oxidants into the system.

Synthesis, characterization and photocatalytic evaluation of visible light activated C-doped TiO2 nanoparticles.

We have demonstrated heterogeneous photocatalytic degradation of microcystin-LR (MC-LR) by visible light activated carbon doped TiO(2) (C-TiO(2)) nanoparticles, synthesized by a modified sol-gel route based on the self-assembly technique exploiting oleic acid as a pore directing agent and carbon source. The C-TiO(2) nanoparticles crystallize in anatase phase despite the low calcination temperature of 350 °C and exhibit a highly porous structure that can be optimized by tuning the concentration of the oleic acid surfactant. The carbon modified nanomaterials exhibited enhanced absorption in the broad visible light region together with an apparent red shift in the optical absorption edge by 0.5 eV (2.69 eV), compared to the 3.18 eV of reference anatase TiO(2). Carbon species were identified by x-ray photoelectron spectroscopy analysis through the formation of both Ti-C and C-O bonds, indicative of substitution of carbon for oxygen atoms and the formation of carbonates, respectively. Electron paramagnetic resonance spectroscopy revealed the formation of two carbon related paramagnetic centers in C-TiO(2), whose intensity was markedly enhanced under visible light illumination, pointing to the formation of localized states within the anatase band gap, following carbon doping. The photocatalytic activity of C-TiO(2) nanomaterials was evaluated for the degradation of MC-LR at pH 3.0 under visible light (λ > 420 nm) irradiation. The doped materials showed a higher MC-LR degradation rate than reference TiO(2), behavior that is attributed to the incorporation of carbon into the titania lattice.

Efficient removal of microcystin-LR by UV-C/H2O2 in synthetic and natural water samples.

The destruction of the commonly found cyanobacterial toxin, microcystin-LR (MC-LR), in surface waters by UV-C/H(2)O(2) advanced oxidation process (AOP) was studied. Experiments were carried out in a bench scale photochemical apparatus with low pressure mercury vapor germicidal lamps emitting at 253.7 nm. The degradation of MC-LR was a function of UV fluence. A 93.9% removal with an initial MC-LR concentration of 1 µM was achieved with a UV fluence of 80 mJ/cm(2) and an initial H(2)O(2) concentration of 882 µM. When increasing the concentration of MC-LR only, the UV fluence-based pseudo-first order reaction rate constant generally decreased, which was probably due to the competition between by-products and MC-LR for hydroxyl radicals. An increase in H(2)O(2) concentration led to higher removal efficiency; however, the effect of HO scavenging by H(2)O(2) became significant for high H(2)O(2) concentrations. The impact of water quality parameters, such as pH, alkalinity and the presence of natural organic matter (NOM), was also studied. Field water samples from Lake Erie, Michigan and St. Johns River, Florida were employed to evaluate the potential application of this process for the degradation of MC-LR. Results showed that the presence of both alkalinity (as 89.6-117.8 mg CaCO(3)/L) and NOM (as ∼2 to ∼9.5 mg/L TOC) contributed to a significant decrease in the destruction rate of MC-LR. However, a final concentration of MC-LR bellow the guideline value of 1 µg/L was still achievable under current experimental conditions when an initial MC-LR concentration of 2.5 µg/L was spiked into those real water samples.