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1.
Trials ; 20(1): 616, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31665085

RESUMO

BACKGROUND: Investigator-initiated clinical studies (IITs) are crucial to generate reliable evidence that answers questions of day-to-day clinical practice. Many challenges make IITs a complex endeavour, for example, IITs often need to be multinational in order to recruit a sufficient number of patients. Recent studies highlighted that well-trained study personnel are a major factor to conduct such complex IITs successfully. As of today, however, no overview of the European training activities, requirements and career options for clinical study personnel exists. METHODS: To fill this knowledge gap, a survey was performed in all 11 member and observer countries of the European Clinical Research Infrastructure Network (ECRIN), using a standardised questionnaire. Three rounds of data collection were performed to maximize completeness and comparability of the received answers. The survey aimed to describe the landscape of academic training opportunities, to facilitate the exchange of expertise and experience among countries and to identify new fields of action. RESULTS: The survey found that training for Good Clinical Practice (GCP) and investigator training is offered in all but one country. A specific training for study nurses or study coordinators is also either provided or planned in ten out of eleven countries. A majority of countries train in monitoring and clinical pharmacovigilance and offer specific training for principal investigators but only few countries also train operators of clinical research organisations (CRO) or provide training for methodology and quality management systems (QMS). Minimal requirements for study-specific functions cover GCP in ten countries. Only three countries issued no requirements or recommendations regarding the continuous training of study personnel. Yet, only four countries developed a national strategy for training in clinical research and the career options for clinical researchers are still limited in the majority of countries. CONCLUSIONS: There is a substantial and impressive investment in training and education of clinical research in the individual ECRIN countries. But so far, a systematic approach for (top-down) strategic and overarching considerations and cross-network exchange is missing. Exchange of available curricula and sets of core competencies between countries could be a starting point for improving the situation.


Assuntos
Pesquisa Biomédica/educação , Ensaios Clínicos como Assunto , Pesquisadores/educação , Currículo , Europa (Continente) , Humanos , Farmacologia Clínica/educação , Farmacovigilância , Inquéritos e Questionários
2.
Dalton Trans ; 45(29): 11596-605, 2016 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-27397634

RESUMO

General considerations on the differences and similarities between heterogeneous photocatalysis and thermal catalysis are presented. Some research papers are reviewed where a reaction has been carried out in the presence of an inorganic material used both as catalyst and photocatalyst. The existing literature often compares catalytic reactions undertaken with the contemporaneous presence of radiation, showing only that photocatalytic reactions can occur under milder experimental conditions and at much lower temperatures. Nevertheless, differences in mechanistic aspects, conversions and selectivities between catalytic and photocatalytic reactions should also be highlighted. These are due to various reasons, relating to the effects of the interaction of light with the solid surface, adsorption-desorption of species involved in the (photo)reactions, and activation energy.

4.
J Antimicrob Chemother ; 71(4): 1056-62, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26702926

RESUMO

OBJECTIVES: To describe the pattern of drug resistance at virological failure in the NEAT001/ANRS143 trial (first-line treatment with ritonavir-boosted darunavir plus either tenofovir/emtricitabine or raltegravir). METHODS: Genotypic testing was performed at baseline for reverse transcriptase (RT) and protease genes and for RT, protease and integrase (IN) genes for patients with a confirmed viral load (VL) >50 copies/mL or any single VL >500 copies/mL during or after week 32. RESULTS: A resistance test was obtained for 110/805 (13.7%) randomized participants qualifying for resistance analysis (61/401 of participants in the raltegravir arm and 49/404 of participants in the tenofovir/emtricitabine arm). No resistance-associated mutation (RAM) was observed in the tenofovir/emtricitabine plus darunavir/ritonavir arm, and all further analyses were limited to the raltegravir plus darunavir arm. In this group, 15/55 (27.3%) participants had viruses with IN RAMs (12 N155H alone, 1 N155H + Q148R, 1 F121Y and 1 Y143C), 2/53 (3.8%) with nucleotide analogue RT inhibitor RAMs (K65R, M41L) and 1/57 (1.8%) with primary protease RAM (L76V). The frequency of IN mutations at failure was significantly associated with baseline VL: 7.1% for a VL of <100,000 copies/mL, 25.0% for a VL of ≥100,000 copies/mL and <500,000 copies/mL and 53.8% for a VL of ≥500,000 copies/mL (PTREND = 0.007). Of note, 4/15 participants with IN RAM had a VL < 200 copies/mL at time of testing. CONCLUSIONS: In the NEAT001/ANRS143 trial, there was no RAM at virological failure in the standard tenofovir/emtricitabine plus darunavir/ritonavir regimen, contrasting with a rate of 29.5% (mostly IN mutations) in the raltegravir plus darunavir/ritonavir NRTI-sparing regimen. The cumulative risk of IN RAM after 96 weeks of follow-up in participants initiating ART with raltegravir plus darunavir/ritonavir was 3.9%.


Assuntos
Terapia Antirretroviral de Alta Atividade , Farmacorresistência Viral , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , Carga Viral , Adulto , Fármacos Anti-HIV/farmacologia , Fármacos Anti-HIV/uso terapêutico , Contagem de Linfócito CD4 , Feminino , Seguimentos , Infecções por HIV/diagnóstico , HIV-1/genética , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mutação , Falha de Tratamento , Resultado do Tratamento
5.
Eur J Clin Microbiol Infect Dis ; 32(12): 1565-70, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24213914

RESUMO

The purpose of this investigation was to determine the impact on human immunodeficiency virus (HIV) tropism of uncontrolled virus exposure during 2 years of intermittent highly active antiretroviral therapy (HAART). The Istituto Superiore di Sanità-Pulsed Antiretroviral Therapy (ISS-PART) randomized study compared the outcome of 2 years of structured treatment interruptions (STIs) versus standard continuous treatment in first-line HAART responder subjects. The STI schedule consisted of five STIs of 1, 1, 2, 2, and 3 months, respectively, separated by four periods of 3-month therapy. In the present study, coreceptor tropism was assessed in 12 patients of the STI arm at different time points over a period of 2 years. Tropism was determined on DNA and RNA by V3 loop region sequencing. The Geno2pheno algorithm (false-positive rate, FPR: 20%) was used for data interpretation. At baseline, 9/12 subjects (75.0%) had CCR5-tropic viruses in their HIV. Three had a CXCR4-tropic virus. Ten patients maintained the same coreceptor in DNA after 2 years, whereas in two patients, a shift occurred (one R5-X4, one X4-R5). In a patient with an R5 virus at baseline, a transient change to X4 tropism was seen in the rebounding virus during STI. Changes in tropism were not associated with the amplitude and duration of virus exposure during STIs, residual viremia at baseline, or the development of resistance mutations in the RT region. Our preliminary results suggest that viral replication, observed after short periods of treatment interruption, is not enough to drive the evolution of HIV tropism.


Assuntos
Antirretrovirais/uso terapêutico , Infecções por HIV/virologia , HIV-1/fisiologia , Receptores CCR5/metabolismo , Receptores CXCR4/metabolismo , Adulto , Terapia Antirretroviral de Alta Atividade , DNA Viral/sangue , DNA Viral/genética , Feminino , Seguimentos , Infecções por HIV/sangue , Infecções por HIV/tratamento farmacológico , Infecções por HIV/metabolismo , HIV-1/genética , HIV-1/patogenicidade , Humanos , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/virologia , Masculino , Pessoa de Meia-Idade , RNA Viral/sangue , RNA Viral/genética , Resultado do Tratamento , Tropismo Viral
6.
Phys Chem Chem Phys ; 15(32): 13329-42, 2013 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-23703460

RESUMO

Catalytic and catalytic photo-assisted hydration of propene to form 2-propanol in gas-solid regime at atmospheric pressure and 85 °C were carried out by using a heteropolyacid (POM) supported on different oxides. Binary materials were prepared by impregnation of H3PW12O40 on different commercial and home prepared supports (TiO2, SiO2, WO3, ZrO2, ZnO, Al2O3). Some of the composites were active both for catalytic and catalytic photo-assisted reactions. The Keggin type POM was completely and partially degraded, when supported on ZnO and Al2O3, respectively, and these binary solids always resulted as inactive for both catalytic and catalytic photo-assisted reactions. The supported Keggin POM species played a key role both for the catalytic and the photo-assisted catalytic reactions, due to their strong acidity and ability to form strong oxidant species under UV irradiation, respectively. The contemporary presence of heat and UV light improved the activity of almost all POM supported materials. All materials were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM), diffuse reflectance spectroscopy (DRS), determination of the conduction and valence band energy by photovoltage measurements, Fourier transform infrared spectroscopy (FTIR), NH3-TPD experiments and time resolved microwave conductivity (TRMC).


Assuntos
Alcenos/química , Óxidos/química , Tungstênio/química , Catálise , Tamanho da Partícula , Processos Fotoquímicos , Pressão , Propriedades de Superfície , Água/química
7.
J Hazard Mater ; 174(1-3): 707-13, 2010 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-19828242

RESUMO

Silica-supported TiO(2) powders were synthesized by a wet method under mild conditions. The aim of the work was the preparation of TiO(2)/SiO(2) additives for photocatalytic cements. Three types of commercial SiO(2) were used as supports: Cabot, Axim and Fly Ash. Cabot silica was ultra-pure whereas the other two silica contained different percentages of various oxides. The TiO(2)/SiO(2) samples, denoted TiO(2)/Cabot, TiO(2)/Axim and TiO(2)/Fly Ash, were prepared by boiling suspensions obtained by addition of silica to a solution of TiCl(4) in water (volume ratio 1:10). The photocatalytic activity was evaluated in a gas-solid system both in batch and in continuous reactors using 2-propanol as probe molecule. SEM-EDX analysis revealed that titanium dioxide was quantitatively deposited on silica. TiO(2)/Axim and TiO(2)/Fly Ash were scarcely active whereas a good photoactivity was exhibited by the TiO(2)/Cabot sample both in the batch and in the continuous system. Consequently only the last sample was tested for both NO(x) abatement and for 4-nitrophenol photodegradation in a liquid-solid system.


Assuntos
Fotoquímica , Dióxido de Silício/química , Titânio/química , Catálise , Microscopia Eletrônica de Varredura , Difração de Raios X
8.
Phys Chem Chem Phys ; 11(20): 4084-93, 2009 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-19440639

RESUMO

Nanocrystalline N-doped TiO(2) samples were prepared by using TiCl(4) or TiOSO(4) as precursors. The powders were characterized by X-ray diffraction, BET specific surface area measurements, scanning electron microscopy, diffuse reflectance spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The photocatalytic activity was tested using the photodegradation of 4-nitrophenol under UV and visible light.Some samples were more active than commercial Degussa P25. A shift of the absorption edge to a lower energy and a stronger absorption in the visible light region were observed in the samples obtained from TiCl(4). Two absorption edges were observed in the samples derived from TiOSO(4) and calcined at 400 degrees C: the main edge due to TiO(2) and the second one due to the presence of a localised midgap band that induces the visible light activity.

9.
J Hazard Mater ; 151(2-3): 356-63, 2008 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-17618048

RESUMO

The colour changes of 4-(2-pyridylazo)-resorcinol and naphthol green beta as new screening metallochromic indicator in back-titration of EDTA excess with Zn(II) to determine Cr(III)/EDTA complex was investigated with the help of tristimulus colorimetry. Specific colour discrimination (SCD) and L*, a*, b* 1976 parameters were successfully applied to evaluate the quality of colour transition at the end-point in non-alkaline media and in the presence of Zn(II) and Ca(II) which resulted in non-interfering species at 1x10(-3) M and 2x10(-3) M, respectively. The above concentrations are comparable with those used for Cr(III). Validation of the fast and accurate reported method was performed by atomic absorption spectroscopy. Moreover, the method was applied for determining Cr as Cr(III) in a wastewater effluent deriving from a leather industry.


Assuntos
Cromo/química , Corantes/farmacologia , Ácido Edético/química , Naftóis/farmacologia , Resorcinóis/farmacologia , Purificação da Água/métodos , Zinco/análise , Cálcio/química , Resíduos Industriais , Modelos Químicos , Modelos Estatísticos , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água , Zinco/química
10.
Mult Scler ; 10(4): 442-6, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15327043

RESUMO

Caregivers of persons with multiple sclerosis (MS) exhibit less satisfaction with quality of life with respect to the general population. To assess the relationship between depression in caregivers and health status profiles of MS patients, we examined data from 133 patients and their respective caregivers, as a part of a prospective randomized trial aimed to investigate the effectiveness of home-based care. Patients were evaluated at baseline and one year later with measures of physical and psychological impairment and health status (SF-36 Health Survey). Caregivers' psychological morbidity was assessed by the Profile of Mood State (POMS) at the same time points. An improvement of patients' health status as measured in four out of eight SF-36 dimensions was observed over the study period, while psychological morbidity of their caregivers did not change significantly. Depression in caregivers was related to physical, emotional and health status of the patients at baseline and/or at 12-month follow-up. Changes in the degree of depression of caregivers were also associated with changes in disability and health status of the patients. This study confirms and extends in a home-care setting previous findings on relationships between patients' status and depression in caregivers. It suggests that the caregiver is an appropriate and independent target for more focused therapeutic strategies.


Assuntos
Cuidadores/psicologia , Depressão , Nível de Saúde , Serviços de Assistência Domiciliar , Esclerose Múltipla/fisiopatologia , Esclerose Múltipla/terapia , Adulto , Afeto , Idoso , Depressão/psicologia , Pessoas com Deficiência , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/psicologia , Equipe de Assistência ao Paciente
11.
Clin Exp Immunol ; 135(2): 280-5, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14738457

RESUMO

A discordant response to highly active antiretroviral therapy (HAART) occurs when CD4 T cell counts are stable or increased over time despite persistently detectable HIV-RNA levels. In order to identify immunological factors affecting discordant treatment responses, a total of 27 HIV-infected patients were studied: (a) 10 naive patients (mean CD4+ = 101.5 cells/microl; mean HIV-RNA = 4.8 log10 copies/ml); (b) seven responder patients (mean CD4+ = 908.9 cells/microl); and (c) 10 discordant patients (mean CD4+ = 396.1 cells/microl; mean HIV-RNA = 5.4 log10 copies/ml). Five healthy blood donors were included as HIV-seronegative controls. The following parameters were evaluated: interleukin (IL)-15 production by monocyte-derived dendritic cells (MDDC) after stimulation with lypopolysaccaride (LPS) and Candida albicans; recall and HIV-1-specific antigen lymphocyte proliferation (LP). Increased levels of IL-15 production by MDDC after stimulation with LPS and C. albicans were found both in discordant patients and responder patients. Conversely, a strong reduction of IL-15 levels was observed in naive patients. Discordant patients developed positive LP responses to C. albicans and HIV-1 p24. LP in response to C. albicans and HIV-1 p24 was also positive in responder patients. Decreased LP response was found in naive patients. In conclusion, HIV-infected patients with discordant viro-immunological responses to HAART present increased levels of IL-15 production by MDDC and enhanced recall and HIV-1-specific antigen LP responses, suggesting an improvement in indices of immune function.


Assuntos
Terapia Antirretroviral de Alta Atividade/métodos , Células Dendríticas/imunologia , Infecções por HIV/imunologia , Interleucina-15/biossíntese , Linfócitos T/imunologia , Adulto , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Candida albicans/imunologia , Células Dendríticas/metabolismo , Feminino , Antígenos HIV/imunologia , Proteína do Núcleo p24 do HIV/imunologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/metabolismo , HIV-1/imunologia , Humanos , Lipopolissacarídeos/imunologia , Ativação Linfocitária/imunologia , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Monócitos/imunologia , RNA Viral/análise
12.
Antivir Ther ; 9(6): 829-48, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15651743

RESUMO

In most European countries, HIV drug resistance testing has become a routine clinical tool. However, its practical implementation in a clinical context is demanding. The European HIV Drug Resistance Panel was established to make recommendations to clinicians and virologists on this topic and to propose quality control measures. The panel recommends resistance testing for the following indications: i) drug-naive patients with acute or recent infection; ii) therapy failure, including suboptimal treatment response, when treatment change is considered; iii) pregnant HIV-1-infected women and paediatric patients with detectable viral load when treatment initiation or change is considered; and iv) genotype source patient when post-exposure prophylaxis is considered. In addition, for drug-naive patients with chronic infection in whom treatment is to be started, the panel suggests that resistance testing should be strongly considered and recommends testing the earliest sample for drug resistance if suspicion of resistance is high or prevalence of resistance in this population exceeds 10%. The panel does not favour genotyping over phenotype, however it is anticipated that genotyping will be used more often because of its greater accessibility, lower cost and faster turnaround time. For the interpretation of resistance data, clinically validated systems should be used to the greatest extent possible. It is mandatory that laboratories performing HIV resistance tests take regular part in quality assurance programs. Similarly, it is necessary that HIV clinicians and virologists take part in continuous education and meet regularly to discuss problematic clinical cases. Indeed, resistance test results should be used in the context of all other clinically relevant information for predicting therapy response. The panel also encourages the timely collection of epidemiological information to estimate the impact of transmission of resistant HIV and the prevalence of HIV-1 non-B subtypes in the different European countries.


Assuntos
Fármacos Anti-HIV/farmacologia , Farmacorresistência Viral , HIV-1/efeitos dos fármacos , Inibidores da Transcriptase Reversa/farmacologia , Fármacos Anti-HIV/uso terapêutico , Farmacorresistência Viral/genética , Europa (Continente) , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , HIV-1/genética , Humanos , Testes de Sensibilidade Microbiana/métodos , Gravidez , Inibidores da Transcriptase Reversa/uso terapêutico
13.
Anal Bioanal Chem ; 378(1): 214-20, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14598010

RESUMO

The degradation of Methyl Orange (C(14)H(14)N(3)SO(3)Na), chosen as a model sulfonated azo dye, was investigated in aqueous solutions containing suspended polycrystalline TiO(2) particles under irradiation with simulated sunlight. The dye disappearance and the formation of the mineralization end products were monitored; the formation of the main transient intermediates was also examined in detail. Particular attention was devoted to the identification and to the evolution of fragments retaining the chromophoric group. The comparison of data coming from various analytical techniques led to a possible reaction mechanism for the degradation process, giving insight into an aspect of the treatment which has not been considered in previous studies.

14.
Chem Commun (Camb) ; (18): 2350-1, 2003 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-14518909

RESUMO

The functionalisation of various heterocyclic bases induced by sunlight is reported. The photoreaction occurred with higher yield in a liquid-solid heterogeneous system in the presence of polycrystalline TiO2 (anatase) than in a homogeneous system under the same experimental conditions.

15.
J Neurol Neurosurg Psychiatry ; 73(3): 250-5, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12185154

RESUMO

BACKGROUND: Home based medical care is a popular alternative to standard hospital care but there is uncertainty about its cost-effectiveness. OBJECTIVES: To compare the effectiveness and the costs of multidisciplinary home based care in multiple sclerosis with hospital care in a prospective randomised controlled trial with a one year follow up. METHODS: 201 patients with clinically definite multiple sclerosis were studied. They were randomised in a ratio 2:1 to an intervention group (133) or a control group (68). They were assessed at baseline and one year after randomisation with validated measures of physical and psychological impairment and quality of life (SF-36 health survey). The costs to the National Health Service over the one year follow up were calculated by a cost minimisation analysis. RESULTS: There were no differences in functional status between the home based care group and the hospital group. There was a significant difference between the two groups favouring home based management in four SF-36 health dimensions-general health, bodily pain, role-emotional, and social functioning (all p < or = 0.001). The cost of home based care was slightly less (822 euros/patient/year) than hospital care, mainly as a result of a reduction in hospital admissions. CONCLUSIONS: Comprehensive planning of home based intervention implemented by an interdisciplinary team and designed specifically for people with multiple sclerosis may provide a cost-effective approach to management and improve the quality of life.


Assuntos
Serviços Hospitalares de Assistência Domiciliar/economia , Esclerose Múltipla/economia , Adulto , Análise Custo-Benefício , Avaliação da Deficiência , Feminino , Seguimentos , Custos de Cuidados de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/reabilitação , Equipe de Assistência ao Paciente
16.
Haematologica ; 86(10): 1051-9, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11602411

RESUMO

BACKGROUND AND OBJECTIVES: Intensive chemotherapy (CHT) in AIDS-related non-Hodgkin's lymphoma (AIDS-NHL patients) is a vexing problem. Our purpose was to evaluate the feasibility of a high dose idarubicin (HD-IDA)-based regimen in diffuse large cell (DLC) AIDS-NHL patients. DESIGN AND METHODS: Fourteen stage I-IV untreated DLC AIDS-NHL patients with a performance status <3 and no prior AIDS-related diseases received CIOD: cyclophosphamide, HD-IDA (25 mg/m2 in 8 patients, 20 mg/m2 in 6 patients) vincristine and dexamethasone plus granulocyte colony-stimulating factor (G-CSF) and prophylaxis against infections. The outcomes measured were: rate of response, disease-free survival (DFS), overall survival (OS) and the impact of chemotherapy on immunologic and virological parameters. RESULTS: Complete response was achieved in 13/14 cases (response rate: 93%). The median time of response and survival was 33 (range 5-79) and 35.5 (range 6-84) months, respectively. At 60 months the DFS and OS were 71% and 44%, respectively. CIOD with idarubicin 20 mg/m2 was better tolerated than that with 25 mg/m2 and was administered with a higher mean average-relative-dose-intensity (95.38+/-7% vs 83.35+/-15.59%, p=0.0001). Opportunistic infections were more frequent in patients with a baseline CD4 <100 than those with >100 cells/microL (4/5 vs 1/9: p=0.0229). After 3 CIOD courses the mean CD4 cells/microL was significantly lower (p=0.001) and the mean HIV.1 RNA load was significantly higher (p=0.045) than at baseline. INTERPRETATION AND CONCLUSIONS: The proposed chemotherapeutic regimen for AIDS-related non-Hodgkin's lymphoma is feasible in an outpatient setting in selected patients with relatively well-preserved immune function.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Idarubicina/administração & dosagem , Linfoma Relacionado a AIDS/tratamento farmacológico , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Adulto , Antibióticos Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/toxicidade , Feminino , Humanos , Linfoma Relacionado a AIDS/sangue , Linfoma Difuso de Grandes Células B/sangue , Linfoma Difuso de Grandes Células B/virologia , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Resultado do Tratamento
18.
Environ Sci Technol ; 35(5): 971-6, 2001 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-11351544

RESUMO

The photocatalytic degradation of the anthraquinonic dye Acid Blue 80 in aqueous solutions containing TiO2 dispersions has been investigated. The process has been monitored by following either the disappearance of the dye (via HPLC) and the formation of its end-products (via IC, GC, and TOC analysis). Although a relatively fast decolorization of the solutions has been observed, the mineralization is slower, and the presence of residual organic compounds was evidenced even after long term irradiation, confirming the relevant stability of anthraquinone derivatives. The identification of various unstable intermediates formed after low irradiation times was performed by HPLC-MS, allowing us to give insight into the early steps of the degradation process which mainly involve C-N bonds breaking and substrate hydroxylation. Complete and relatively fast mineralization of the substrate was achieved by irradiating the semiconductor dispersions in the presence of added K2S2O8.


Assuntos
Antraquinonas/química , Corantes/química , Titânio/química , Hidroxilação , Fotólise , Poluentes Químicos da Água/análise
19.
Ann Chim ; 91(3-4): 127-36, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11381536

RESUMO

The possibility of entrapping polycrystalline TiO2 in a polymeric support, in order to couple the two unit operations, i.e. ultrafiltration and photodegradation of organic pollutants in aqueous solutions, was investigated. To this aim, polymeric membranes for ultrafiltration with entrapped TiO2 were prepared, characterised and tested. The polymeric support chosen was commercial polysulfone (PSf). The membrane preparation was carried out with the technique referred to as phase inversion. A three-component system, with a polymer, a solvent and a non-solvent was used. The best operative conditions were determined in order to obtain the desired membrane morphology. Permeability measurements and photostability tests were also carried out by using a system under pressure. Finally, a preliminary investigation was performed in order to evaluate the photocatalytic activity of the membranes with entrapped TiO2 for the oxidation of 4-nitrophenol as a model molecule in aqueous solutions.


Assuntos
Membranas Artificiais , Titânio/química , Poluentes Químicos da Água/análise , Catálise , Nitrofenóis/química , Oxirredução , Tamanho da Partícula , Permeabilidade , Fotoquímica , Polímeros/química , Sulfonas/química , Ultrafiltração/métodos
20.
Ann Chim ; 91(3-4): 197-202, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11381545

RESUMO

Degradation tests in a photocatalytic membrane system have been carried out using TiO2 (Degussa P25) as catalyst and humic acid, organic dyes, 4-nitrophenol as pollutants. The influence of UV radiation and initial concentration of pollutant on the photodegradation rate were investigated in discontinuous and continuous systems. Experimental results showed that it is possible to obtain an efficient photocatalytic membrane process, but various parameters (e.g. pH) should be optimised to obtain high reaction rate and high membrane rejection of pollutants and their by-products.


Assuntos
Compostos Orgânicos/química , Titânio/química , Poluentes Químicos da Água , Catálise , Concentração de Íons de Hidrogênio , Resíduos Industriais , Membranas Artificiais
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