Química para comprender el mundo: Dos ejemplos ambientales

Vivimos en un mundo de sustancias químicas, muchas son de origen natural y otras sintéticas. Las sustancias químicas están presentes en los alimentos, medicinas, vitaminas, pinturas, pegamentos, productos de limpieza, materiales de construcción, automóviles, equipos electrónicos, equipos deportivos, fibras naturales, fibras sintéticas, entre otros.Fil: Sala, Luis Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentin

Reacciones de eliminación-beta en aldonolactonas : Descarboxilación oxidativa de aldonolactonas con sulfato cérico. Síntesis de 2-Desoxi-azúcares

Fil:Sala, Luis Federico. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Reduction of hypervalent chromium in acidic media by alginic acid

Selective oxidation of carboxylate groups present in alginic acid by CrVI affords CO2, oxidized alginic acid, and CrIII as final products. The redox reaction afforded first-order kinetics in [alginic acid], [CrVI], and [H+], at fixed ionic strength and temperature. Kinetic studies showed that the redox reaction proceeds through a mechanism which combines CrVI →CrIV → CrII and CrVI → CrIV → CrIII pathways. The mechanism was supported by the observation of free radicals, CrO22+ and CrV as reaction intermediates. The reduction of CrIV and CrV by alginic acid was independently studied and it was found to occur more than 103 times faster than alginic acid/CrVI reaction, in acid media. At pH 1–3, oxo-chromate(V)–alginic acid species remain in solution during several hours at 15 °C. The results showed that this abundant structural polysaccharide present on brown seaweeds is able to reduce CrVI/V/IV or stabilize high-valent chromium depending on pH value.Fil: Bertoni, Fernando Ariel. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; ArgentinaFil: Bellú, Sebastián Eduardo. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; ArgentinaFil: González, Juan Carlos. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; ArgentinaFil: Sala, Luis Federico. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; Argentin

Oligo and polyuronic acids interactions with hypervalent chromium

Selective oxidation of galacturonic residues of oligo and polyuronic acids by CrVI affords CO2/HCO2H, oxidized uronic acid, and CrIII as final redox products. Kinetic studies show that the redox reaction proceeds through a mechanism combining CrVI → CrIV → CrII and CrVI → CrIV → CrIII pathways. The mechanism is supported by the observation of free radicals, CrO22+ and CrV as reaction intermediates. The EPR spectra show that five- and six coordinated oxo-CrV intermediates are formed. Penta-coordinated oxo-CrV species are present at any [H+], whereas hexa-coordinated ones are only observed at pH <1. At low pH CrV predominating species are coordinated by carboxylate groups and Oring (giso = 1.9783/5). At pH 7.5, the predominating ones are those coordinated by alcoholate groups of the ligand (giso = 1.9800). Polygal can reduce CrVI and efficiently trap CrIII. This behaviour represents an interesting model for the study of biomaterials, which possess a high proportion of polygal, in order to remove chromium from polluted waters.Fil: González, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: García, Silvia Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Bellú, Sebastián Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Atria, Ana María. Universidad de Chile; ChileFil: Salas Pelegrín, Juan Manuel. Universidad de Granada. Facultad de Ciencias; EspañaFil: Rockenbauer, Antal. Hungary Academy of Sciences. Chemical Research Center; HungríaFil: Korecz, Lazlo. Hungary Academy of Sciences. Chemical Research Center; HungríaFil: Signorella, Sandra Rosanna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Sala, Luis Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentin

Biosorption of Trivalent Chromium from Aqueous Solution by Red Seaweed Polysiphonia nigrescens

This paper presents the biosorption of chromium onto red seaweed (Polysiphonia nigrescens). Batch mode experiments were performed to determine experimental parameters affecting sorption process such as pH, contact time, initial metal ion concentration and biomass dosage. The Cr(III) sorption was dependent on pH and adsorbent dosage. The adsorption kinetic data could be fitted with a pseudo-second-order model and the equilibrium data with a Langmuir model. The maximum sorption capacity was of 16.11 mg/g at pH 4 and 10 g/L of biomass dosage. 0.1 M H2SO4 showed good desorption efficiency (>80%). Spectroscopy analysis showed that Cr(III) sorption on seaweed was mainly through the ion-exchange mechanism. This report indicates that P. nigrescens is an effective and economical sorbent for removal of Cr(III) from wastewaters.Fil: Blanes, Patricia Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Sala, Luis Federico. Universidad Nacional de Rosario. Facultad de Cs.bioquímicas y Farmaceuticas. Departamento de Química y Física. Area Inorganica; ArgentinaFil: García, Silvia I.. Universidad Nacional de Rosario. Facultad de Cs.bioquímicas y Farmaceuticas. Departamento de Química y Física. Area Inorganica; ArgentinaFil: González, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Fracaroli, María I.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Harada, Masafumi. Nara Women’s University; JapónFil: Cong, Cong. High Energy Accelerator Research Organization; JapónFil: Niwa, Yasuhiro. High Energy Accelerator Research Organization; JapónFil: Matulewicz, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Prado, Héctor Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Cortadi, Adriana Amalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Gattuso, Martha. Universidad Nacional de Rosario. Facultad de Cs.bioquímicas y Farmaceuticas. Departamento de Química y Física. Area Inorganica; Argentin

Transdisciplinary studies in socio-ecosystems: Theoretical considerations and its application in Latin American contexts

Debido a limitaciones para abordar la complejidad de la relación sociedad-naturaleza, los esfuerzos para solucionar los problemas ambientales han sido en general infructuosos. Aquí proponemos que el enfoque holístico de “socio-ecosistema” por parte de la academia, podría contribuir a disminuir estas limitaciones desde la adopción de cuatro cambios: i) ontológico, que presenta el concepto de “socio-ecosistemas”; ii) epistemológico, que propone a la transdisciplina como la forma de entenderlos, iii) metodológico, que sugiere intervenir en ellos de forma participativa y adaptativa y, iv) cambios institucionales que facilitarían la adopción de esta propuesta. Este planteamiento se complementa con la descripción de una experiencia transdiciplinaria en la cuenca del río San Juan Zitácuaro, México, en el contexto de un curso internacional de manejo de socio-ecosistemas.Given the difficulties to approach the complex relationship bettween society and nature, efforts to solve environmental problems have generally been unsuccessful. Here we suggest that a hollistic “socio-ecosystem” approach by the sciencies could help diminish these difficulties by embracing four kinds of changes: i) ontological, which introduces the concept of “socio-ecosystem”; ii) epistemological, which proposes transdiscipline as the way to understand them, iii) metholodogical, which suggests that in intervention in them must be participatory and adaptive, iv) institutional changes that would facilitate the adoption of this approach. This is then followed by a description of a transdisciplinary work experience in the Zitácuaro river basin, in Mexico, in the context of an international course on socio-ecosystem management.Fil: Ortega Uribe, Tamara. Universidad de Chile; ChileFil: Mastrangelo, Matias Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Villarroel Torrez, Daniel. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Piaz, Agustín Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Humanidades. Centro de Estudios de Historia de la Ciencia y de la Técnica ; ArgentinaFil: Vallejos, María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Saenz Ceja, Jesús Eduardo. Universidad Nacional Autónoma de México. Centro de Investigaciones en Ecosistemas; MéxicoFil: Gallego, Federico. Universidad de la República. Facultad de Ciencias; UruguayFil: Franquesa Soler, Monserrat. Instituto de Ecología; MéxicoFil: Calzada Peña, Leonardo. Universidad Nacional Autónoma de México; MéxicoFil: Espinosa Mellado, Noelia. Universidad de la Armada; MéxicoFil: Fiestas Flores, Jerico. Instituto de Estudios Peruanos; PerúFil: Gill Mairhofer, Luis R.. Ministerio de la Defensa Pública; ParaguayFil: González Espino, Zarahí. Instituto Superior de Tecnologías y Ciencias Aplicadas. Facultad de Medio Ambiente. Departamento de Meteorología; CubaFil: Luna Salguero, Betsabé Montserrat. Sociedad de Historia Natural Niparajá; MéxicoFil: Martinez Peralta, Claudia María. Comisión de Ecología y Desarrollo Sustentable del Estado de Sonora. Dirección General de Conservación; MéxicoFil: Ochoa, Olivia. Universidad Nacional Autónoma de México; MéxicoFil: Pérez Volkow,Lucía. No especifica;Fil: Sala, Juan Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Sánchez Rose, Isabelle. Universidad Central de Venezuela; VenezuelaFil: Weeks, Madeline. University of Cambridge; Reino UnidoFil: Ávila García, Daniela. Universidad Nacional Autónoma de México; MéxicoFil: García Reyes, Isabel Bueno. Universidad Nacional Autónoma de México. Centro de Investigaciones en Ecosistemas; MéxicoFil: Carmona, Alejandra. Universidad Austral de Chile. Instituto de Economía Agraria; ChileFil: Castro Videla, Fernando Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan; ArgentinaFil: Ferrer Gonzalez, César Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; ArgentinaFil: Frank Buss, María Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Pampa. Facultad de Agronomía; ArgentinaFil: López Carapia, Gabriela. Universidad Nacional Autónoma de México; MéxicoFil: Núñez Cruz, Martha. Universidad Nacional Autónoma de México; MéxicoFil: Taboada Hermoza, Rossi. Universidad Nacional Mayor de San Marcos; PerúFil: Benet, Daniel. Alternare A. C.; MéxicoFil: Venegas, Ysmael. Alternare A. C.; MéxicoFil: Balvanera, Patricia. Universidad Nacional Autónoma de México. Centro de Investigaciones en Ecosistemas; MéxicoFil: Mwampamba, Tuyeni H.. Universidad Nacional Autónoma de México. Centro de Investigaciones en Ecosistemas; MéxicoFil: Lazos Chavero, Elena. Universidad Nacional Autónoma de México. Centro de Investigaciones en Ecosistemas; MéxicoFil: Noellemeyer, Elke Johanna. Universidad Nacional de La Pampa. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Maass, Manuel. Universidad Nacional Autónoma de México. Centro de Investigaciones en Ecosistemas; Méxic

Assessing the impact of COVID-19 on liver cancer management (CERO-19).

BACKGROUND & AIMS: The coronavirus disease 2019 (COVID-19) pandemic has posed unprecedented challenges to healthcare systems and it may have heavily impacted patients with liver cancer (LC). Herein, we evaluated whether the schedule of LC screening or procedures has been interrupted or delayed because of the COVID-19 pandemic. METHODS: An international survey evaluated the impact of the COVID-19 pandemic on clinical practice and clinical trials from March 2020 to June 2020, as the first phase of a multicentre, international, and observational project. The focus was on patients with hepatocellular carcinoma or intrahepatic cholangiocarcinoma, cared for around the world during the first COVID-19 pandemic wave. RESULTS: Ninety-one centres expressed interest to participate and 76 were included in the analysis, from Europe, South America, North America, Asia, and Africa (73.7%, 17.1%, 5.3%, 2.6%, and 1.3% per continent, respectively). Eighty-seven percent of the centres modified their clinical practice: 40.8% the diagnostic procedures, 80.9% the screening programme, 50% cancelled curative and/or palliative treatments for LC, and 41.7% modified the liver transplantation programme. Forty-five out of 69 (65.2%) centres in which clinical trials were running modified their treatments in that setting, but 58.1% were able to recruit new patients. The phone call service was modified in 51.4% of centres which had this service before the COVID-19 pandemic (n = 19/37). CONCLUSIONS: The first wave of the COVID-19 pandemic had a tremendous impact on the routine care of patients with liver cancer. Modifications in screening, diagnostic, and treatment algorithms may have significantly impaired the outcome of patients. Ongoing data collection and future analyses will report the benefits and disadvantages of the strategies implemented, aiding future decision-making. LAY SUMMARY: The coronavirus disease 2019 (COVID-19) pandemic has posed unprecedented challenges to healthcare systems globally. Herein, we assessed the impact of the first wave pandemic on patients with liver cancer and found that routine care for these patients has been majorly disrupted, which could have a significant impact on outcomes

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial

Background: Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke. Methods: We did a double-blind, randomised, placebo-controlled trial in 610 sites across 28 countries. We randomly assigned patients aged 40 years and older with type 2 diabetes and cardiovascular disease (at a 1:1 ratio) to groups that either received a subcutaneous injection of albiglutide (30–50 mg, based on glycaemic response and tolerability) or of a matched volume of placebo once a week, in addition to their standard care. Investigators used an interactive voice or web response system to obtain treatment assignment, and patients and all study investigators were masked to their treatment allocation. We hypothesised that albiglutide would be non-inferior to placebo for the primary outcome of the first occurrence of cardiovascular death, myocardial infarction, or stroke, which was assessed in the intention-to-treat population. If non-inferiority was confirmed by an upper limit of the 95% CI for a hazard ratio of less than 1·30, closed testing for superiority was prespecified. This study is registered with ClinicalTrials.gov, number NCT02465515. Findings: Patients were screened between July 1, 2015, and Nov 24, 2016. 10 793 patients were screened and 9463 participants were enrolled and randomly assigned to groups: 4731 patients were assigned to receive albiglutide and 4732 patients to receive placebo. On Nov 8, 2017, it was determined that 611 primary endpoints and a median follow-up of at least 1·5 years had accrued, and participants returned for a final visit and discontinuation from study treatment; the last patient visit was on March 12, 2018. These 9463 patients, the intention-to-treat population, were evaluated for a median duration of 1·6 years and were assessed for the primary outcome. The primary composite outcome occurred in 338 (7%) of 4731 patients at an incidence rate of 4·6 events per 100 person-years in the albiglutide group and in 428 (9%) of 4732 patients at an incidence rate of 5·9 events per 100 person-years in the placebo group (hazard ratio 0·78, 95% CI 0·68–0·90), which indicated that albiglutide was superior to placebo (p&lt;0·0001 for non-inferiority; p=0·0006 for superiority). The incidence of acute pancreatitis (ten patients in the albiglutide group and seven patients in the placebo group), pancreatic cancer (six patients in the albiglutide group and five patients in the placebo group), medullary thyroid carcinoma (zero patients in both groups), and other serious adverse events did not differ between the two groups. There were three (&lt;1%) deaths in the placebo group that were assessed by investigators, who were masked to study drug assignment, to be treatment-related and two (&lt;1%) deaths in the albiglutide group. Interpretation: In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events. Evidence-based glucagon-like peptide 1 receptor agonists should therefore be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events in patients with type 2 diabetes. Funding: GlaxoSmithKline