2,005 research outputs found

    Direct esterification of cinnamic acids with phenols and imidoalcohols: a simple, heteropolyacid-catalyzed procedure

    Get PDF
    A convenient procedure for the direct esterification of cinnamic acids with phenols or 2-(N-phthalimido) ethanol is described. The method is simple and clean, environmentally friendly and high-yielding for both electron-releasing and electron-withdrawing substituted phenols. The heteropolyacid H 6P2W18O62·24 H2O was employed as catalyst, both bulk and supported on silica. No stoichiometric activation of the carboxyl group or condensing reagents is necessary. The effects of temperature, reaction time, amount of the catalyst used and mole ratio of the reactants on the ester yield were checked. Suitable conditions for the reaction include a 1:1 molar ratio of reactants and a 1 mmol % mass ratio of catalyst to reactant. Eighteen aryl and phthalimidoethyl cinnamates were obtained, yields ranged in 84-95% for most of the esters. The catalyst shown to be reusable for at least three times without occurring an appreciable loss of its activity.Facultad de Ciencias Agrarias y ForestalesCentro de Investigación y Desarrollo en Ciencias Aplicada

    Direct esterification of cinnamic acids with phenols and imidoalcohols: a simple, heteropolyacid-catalyzed procedure

    Get PDF
    A convenient procedure for the direct esterification of cinnamic acids with phenols or 2-(N-phthalimido) ethanol is described. The method is simple and clean, environmentally friendly and high-yielding for both electron-releasing and electron-withdrawing substituted phenols. The heteropolyacid H 6P2W18O62·24 H2O was employed as catalyst, both bulk and supported on silica. No stoichiometric activation of the carboxyl group or condensing reagents is necessary. The effects of temperature, reaction time, amount of the catalyst used and mole ratio of the reactants on the ester yield were checked. Suitable conditions for the reaction include a 1:1 molar ratio of reactants and a 1 mmol % mass ratio of catalyst to reactant. Eighteen aryl and phthalimidoethyl cinnamates were obtained, yields ranged in 84-95% for most of the esters. The catalyst shown to be reusable for at least three times without occurring an appreciable loss of its activity.Facultad de Ciencias Agrarias y ForestalesCentro de Investigación y Desarrollo en Ciencias Aplicada

    Silicagel-supported H6P2W18O 62.24H2O: A reusable catalyst to prepare diphenylmethyl (DPM) ethers

    Get PDF
    In this work, we report an efficient and facile preparation of diphenylmethylethers (benzydryl ethers, DPM-ethers) from benzhydrol and alcohols or phenols. Wells-Dawson heteropolyacid (H6P2W 18O62.24H2O), bulk or supported on silica showed catalytic activity for DPM-ethers preparation in toluene, at 60-80°C, in 0.5-1.5h. In these conditions twelve diphenylmethylethers of alcohols and phenol were obtained which excellent yields (78-96%). The heterogeneous reaction conditions provided a very simple, environmentally friendly, clean, economical and selective protocol, for the preparation of unsymmetrical ethers. The catalyst is easily recycled and reused without loss of the catalytic activity.Facultad de Ciencias Agrarias y ForestalesCentro de Investigación y Desarrollo en Ciencias Aplicada

    Silicagel-supported H6P2W18O 62.24H2O: A reusable catalyst to prepare diphenylmethyl (DPM) ethers

    Get PDF
    In this work, we report an efficient and facile preparation of diphenylmethylethers (benzydryl ethers, DPM-ethers) from benzhydrol and alcohols or phenols. Wells-Dawson heteropolyacid (H6P2W 18O62.24H2O), bulk or supported on silica showed catalytic activity for DPM-ethers preparation in toluene, at 60-80°C, in 0.5-1.5h. In these conditions twelve diphenylmethylethers of alcohols and phenol were obtained which excellent yields (78-96%). The heterogeneous reaction conditions provided a very simple, environmentally friendly, clean, economical and selective protocol, for the preparation of unsymmetrical ethers. The catalyst is easily recycled and reused without loss of the catalytic activity.Facultad de Ciencias Agrarias y ForestalesCentro de Investigación y Desarrollo en Ciencias Aplicada

    Silicagel-supported H6P2W18O 62.24H2O: A reusable catalyst to prepare diphenylmethyl (DPM) ethers

    Get PDF
    In this work, we report an efficient and facile preparation of diphenylmethylethers (benzydryl ethers, DPM-ethers) from benzhydrol and alcohols or phenols. Wells-Dawson heteropolyacid (H6P2W 18O62.24H2O), bulk or supported on silica showed catalytic activity for DPM-ethers preparation in toluene, at 60-80°C, in 0.5-1.5h. In these conditions twelve diphenylmethylethers of alcohols and phenol were obtained which excellent yields (78-96%). The heterogeneous reaction conditions provided a very simple, environmentally friendly, clean, economical and selective protocol, for the preparation of unsymmetrical ethers. The catalyst is easily recycled and reused without loss of the catalytic activity.Facultad de Ciencias Agrarias y ForestalesCentro de Investigación y Desarrollo en Ciencias Aplicada

    Direct esterification of cinnamic acids with phenols and imidoalcohols: a simple, heteropolyacid-catalyzed procedure

    Get PDF
    A convenient procedure for the direct esterification of cinnamic acids with phenols or 2-(N-phthalimido) ethanol is described. The method is simple and clean, environmentally friendly and high-yielding for both electron-releasing and electron-withdrawing substituted phenols. The heteropolyacid H 6P2W18O62·24 H2O was employed as catalyst, both bulk and supported on silica. No stoichiometric activation of the carboxyl group or condensing reagents is necessary. The effects of temperature, reaction time, amount of the catalyst used and mole ratio of the reactants on the ester yield were checked. Suitable conditions for the reaction include a 1:1 molar ratio of reactants and a 1 mmol % mass ratio of catalyst to reactant. Eighteen aryl and phthalimidoethyl cinnamates were obtained, yields ranged in 84-95% for most of the esters. The catalyst shown to be reusable for at least three times without occurring an appreciable loss of its activity.Facultad de Ciencias Agrarias y ForestalesCentro de Investigación y Desarrollo en Ciencias Aplicada

    Treatment of nonmetastatic unilateral retinoblastoma in children

    Get PDF
    IMPORTANCE: Multi-institutional collaborative studies that include large patient populations for the management of retinoblastoma with histopathological risk factors could provide important information for patient management. OBJECTIVE: To evaluate the implementation of a strategy for the management of nonmetastatic unilateral retinoblastoma in children based on standardized diagnostic and treatment criteria. DESIGN, SETTING, AND PARTICIPANTS: This single-arm prospective study applied a strategy based on a single-center experience. The setting was a multicenter study in Latin America (Grupo de America Latina de Oncologia Pediatrica [GALOP]). Participants were children with nonmetastatic unilateral retinoblastoma (staged with the International Retinoblastoma Staging System). The study opened on July 1, 2008, and closed on December 31, 2014. Follow-up was updated until June 30, 2017. INTERVENTIONS: Stage 0 patients (without enucleation) were given conservative therapy without a protocol. Stage I patients (with enucleation and no residual tumor) were divided into a high-risk group (retrolaminar invasion and/or scleral invasion) and a low-risk group (all remaining patients). High-risk children received adjuvant chemotherapy with 4 alternating cycles of regimen 1 (cyclophosphamide [65mg/kg/d] [plus sodium-2-mercaptoethane sulfonate], idarubicin hydrochloride [10mg/m2/d], and vincristine sulfate [0.05mg/kg/d]) and 4 cycles of regimen 2 (carboplatin [500mg/m2/d, days 1 and 2] and etoposide [100mg/m2/d, days 1-3]). Low-risk children did not receive adjuvant therapy. Children with buphthalmia received neoadjuvant and adjuvant chemotherapy for a total of 8 cycles. MAIN OUTCOMES AND MEASURES: Probability of event-free survival (extraocular relapse and death from any cause were considered events). RESULTS: Among 187 children registered in the study, 175 were evaluable (92 [52.5%] female; median age, 22 months; age range, 3-100 months). Forty-two were stage 0 children, 84 were stage I low-risk children, and 42 were stage I high-risk children; there were 7 children in the buphthalmia group. With a median follow-up of 46 months, the 3-year probability of event-free survival was 0.97 (95%CI, 0.94-0.99), and the probability of overall survival was 0.98 (95%CI, 0.94-1.00). Stage 0 patients had no events, stage I low-risk patients had 1 event (orbital relapse treated with second-line therapy), stage I high-risk patients had 2 events (1 central nervous system relapse and 1 death from sepsis), and the buphthalmia group had 1 event (orbital relapse, followed by central nervous relapse and death). CONCLUSIONS AND RELEVANCE: Adjuvant therapymay be effective for high-risk unilateral retinoblastoma but is toxic, and neoadjuvant chemotherapy for buphthalmus appears feasible.Fil: Pérez, Verónica. Hospital San Juan de Dios; ChileFil: Sampor, Claudia. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Rey, Guadalupe. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Parareda Salles, Andreu. Hospital Sant Joan de Déu; EspañaFil: Kopp, Katherine. Hospital Dr. Luis Calvo Mackenna Hospital; ChileFil: Dabezies, Agustín P.. Hospital Pereyra Rossell; UruguayFil: Dufort, Gustavo. Hospital Pereyra Rossell; UruguayFil: Zelter, Marta. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: López, Juan P.. Hospital Calvo Mackenna; ChileFil: Urbieta, Marcelo. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Alcalde Ruiz, Elisa. Hospital Dr. Luis Calvo Mackenna Hospital; ChileFil: Catala Mora, Jaume. Hospital Sant Joan de Déu; EspañaFil: Suñol, Mariona. Hospital Sant Joan de Déu; EspañaFil: Ossandon, Diego. Hospital San Juan de Dios; ChileFil: Fandiño, Adriana Cristina. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Croxatto, Juan Oscar. Fundación Oftalmología Argentina "J. Malbrán"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: De Dávila, María T. G.. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Reaman, Gregory. Center for Drug Evaluation and Research; Estados UnidosFil: Ravindranath, Yaddanapudi. Children’s Hospital of Michigan; Estados UnidosFil: Chantada, Guillermo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentin

    Safety and immediate humoral response of COVID-19 vaccines in chronic kidney disease patients:the SENCOVAC study

    Get PDF
    BACKGROUND: Chronic kidney disease (CKD) patients are at high-risk for severe Covid-19. The multicentric, observational and prospective SENCOVAC study aims to describe the humoral response and safety of SARS-CoV-2 vaccines in CKD patients. Safety and immediate humoral response results are reported here. METHODS: Four cohorts of patients were included: kidney transplant (KT) recipients, haemodialysis (HD), peritoneal dialysis (PD) and non-dialysis CKD patients from 50 Spanish centres. Adverse events after vaccine doses were recorded. At baseline and on day 28 after the last vaccine dose, anti-Spike antibodies were measured and compared between cohorts. Factors associated with development of anti-Spike antibodies were analyzed. RESULTS: 1746 participants were recruited: 1116 HD, 171 PD, 176 non-dialysis CKD patients and 283 KT recipients. Most patients (98%) received mRNA vaccines. At least one vaccine reaction developed after the first dose in 763 (53.5%) and after the second dose in 741 (54.5%) of patients. Anti-Spike antibodies were measured in the first 301 patients. At 28 days, 95% of patients had developed antibodies: 79% of KT, 98% of HD, 99% of PD and 100% of non-dialysis CKD patients (p<0.001). In a multivariate adjusted analysis, absence of an antibody response was independently associated to KT (OR 20.56, p = 0.001) and to BNT162b2 vaccine (OR 6.03, p = 0.023). CONCLUSION: The rate of anti-Spike antibody development after vaccination in KT patients was low but in other CKD patients it approached 100%; suggesting that KT patients require persistent isolation measures and booster doses of a Covid-19 vaccine. Potential differences between Covid-19 vaccines should be explored in prospective controlled studies

    The atmospheric science of JEM-EUSO

    Get PDF
    An Atmospheric Monitoring System (AMS) is critical suite of instruments for JEM-EUSO whose aim is to detect Ultra-High Energy Cosmic Rays (UHECR) and (EHECR) from Space. The AMS comprises an advanced space qualified infrared camera and a LIDAR with cross checks provided by a ground-based and airborne Global Light System Stations. Moreover the Slow Data Mode of JEM-EUSO has been proven crucial for the UV background analysis by comparing the UV and IR images. It will also contribute to the investigation of atmospheric effects seen in the data from the GLS or even to our understanding of Space Weather

    Glutathione S-transferase mu 1 (GSTM1) and theta 1 (GSTT1) genetic polymorphisms and atopic asthma in children from Southeastern Brazil

    Get PDF
    Xenobiotics can trigger degranulation of eosinophils and mast cells. In this process, the cells release several substances leading to bronchial hyperactivity, the main feature of atopic asthma (AA). GSTM1 and GSTT1 genes encode enzymes involved in the inactivation of these compounds. Both genes are polymorphic in humans and have a null variant genotype in which both the gene and corresponding enzyme are absent. An increased risk for disease in individuals with the null GST genotypes is therefore, but this issue is controversial. The aim of this study was to investigate the influence of the GSTM1 and GSTT1 genotypes on the occurrence of AA, as well as on its clinical manifestations. Genomic DNA from 86 patients and 258 controls was analyzed by polymerase chain reaction. The frequency of the GSTM1 null genotype in patients was higher than that found in controls (60.5% versus 40.3%, p = 0.002). In individuals with the GSTM1 null genotype the risk of manifested AA was 2.3-fold higher (95%CI: 1.4-3.7) than for others. In contrast, similar frequencies of GSTT1 null and combined GSTM1 plus GSTT1 null genotypes were seen in both groups. No differences in genotype frequencies were perceived in patients stratified by age, gender, ethnic origin, and severity of the disease. These results suggest that the inherited absence of the GSTM1 metabolic pathway may alter the risk of AA in southeastern Brazilian children, although this must be confirmed by further studies with a larger cohort of patients and age-matched controls from the distinct regions of the country
    • …
    corecore