Sintesi di acido glucarico da d-glucosio con catalizzatori a base di oro nanoparticellare

L’utilizzo delle biomasse rappresenta oggi una delle vie più interessanti da percorrere nell’ambito di una chimica industriale maggiormente sostenibile, alternativa alla chimica tradizionale basata sulle risorse fossili. I carboidrati sono i costituenti maggioritari della biomassa e potrebbero rappresentare un’alternativa ideale al petrolio per la produzione dei building-blocks, molecole di partenza per lo sviluppo della filiera produttiva della chimica. Fra i building-blocks ottenibili dagli zuccheri vi è l’acido glucarico. I suoi usi sono molteplici ma suscita grande interesse soprattutto per la possibilità di essere utilizzato nella sintesi di diverse tipologie di polimeri. Attualmente la maggior parte dei metodi di sintesi di questa molecola prevedono l’utilizzo di ossidanti tossici o dannosi per l’ambiente come l’acido nitrico. Lo scopo di questo lavoro di tesi è stato lo studio di catalizzatori eterogenei per la sintesi di acido glucarico da D-glucosio utilizzando ossigeno puro come ossidante. Sono stati sintetizzati sistemi monometallici a base di oro e sistemi multimetallici contenenti oro ed altri metalli in lega. Tutti i catalizzatori sono stati preparati depositando i metalli sotto forma di nanoparticelle su carbone attivo. Lo studio dei catalizzatori è stato focalizzato sull’individuazione dei metalli e delle condizioni di reazione ottimali che permettano di aumentare la selettività in acido glucarico. Gli studi condotti hanno portato alla conclusione che è possibile ottenere acido glucarico a partire da D-glucosio con rese fino al 35% utilizzando catalizzatori a base di oro in presenza di ossigeno. Attualmente l’acido glucarico viene prodotto solo su piccola scala ma ulteriori sviluppi in questa direzione potrebbero aprire la strada allo sviluppo di un nuovo processo industriale per la sintesi di acido glucarico sostenibile sia da un punto di vista economico che ambientale.

Il GNSS per il controllo delle deformazioni crostali

Se pensiamo ad un generico punto sulla superficie terreste questo sarà soggetto allo spostamento nel tempo della propria posizione, a causa delle deformazioni della crosta terrestre. Se conosciamo l’intensità e la direzione dello spostamento possiamo esprimere la variazione delle coordinate del punto in un sistema di riferimento geodetico , in funzione del tempo. Varie teorie spiegano la causa di tali deformazioni crostali (ES. La Tettonica a Placche) , attribuendo l’origine a movimenti convettivi del mantello, determinati dalla variazione spaziale della densità ed al progressivo rilascio degli sforzi accumulati nella litosfera a causa del peso delle massi di ghiaccio che, hanno ricoperto parte della superficie terrestre nelle glaciazioni passate. Fin dagli anni’80 il GNSS è divento una tra le tecniche più idonee per andare a valutare lo spostamento della crosta terrestre rispetto ad un sistema di riferimento globale e regionale grazie all’elevato grado di precisione conseguibile.

Re-evaluating adjuvant breast cancer trials: assessing hormone receptor status by immunohistochemical versus extraction assays

BACKGROUND: Tumor levels of steroid hormone receptors, a factor used to select adjuvant treatment for early-stage breast cancer, are currently determined with immunohistochemical assays. These assays have a discordance of 10%-30% with previously used extraction assays. We assessed the concordance and predictive value of hormone receptor status as determined by immunohistochemical and extraction assays on specimens from International Breast Cancer Study Group Trials VIII and IX. These trials predominantly used extraction assays and compared adjuvant chemoendocrine therapy with endocrine therapy alone among pre- and postmenopausal patients with lymph node-negative breast cancer. Trial conclusions were that combination therapy provided a benefit to pre- and postmenopausal patients with estrogen receptor (ER)-negative tumors but not to ER-positive postmenopausal patients. ER-positive premenopausal patients required further study. METHODS: Tumor specimens from 571 premenopausal and 976 postmenopausal patients on which extraction assays had determined ER and progesterone receptor (PgR) levels before randomization from October 1, 1988, through October 1, 1999, were re-evaluated with an immunohistochemical assay in a central pathology laboratory. The endpoint was disease-free survival. Hazard ratios of recurrence or death for treatment comparisons were estimated with Cox proportional hazards regression models, and discriminatory ability was evaluated with the c index. All statistical tests were two-sided. RESULTS: Concordance of hormone receptor status determined by both assays ranged from 74% (kappa = 0.48) for PgR among postmenopausal patients to 88% (kappa = 0.66) for ER in postmenopausal patients. Hazard ratio estimates were similar for the association between disease-free survival and ER status (among all patients) or PgR status (among postmenopausal patients) as determined by the two methods. However, among premenopausal patients treated with endocrine therapy alone, the discriminatory ability of PgR status as determined by immunohistochemical assay was statistically significantly better (c index = 0.60 versus 0.51; P = .003) than that determined by extraction assay, and so immunohistochemically determined PgR status could predict disease-free survival. CONCLUSIONS: Trial conclusions in which ER status (for all patients) or PgR status (for postmenopausal patients) was determined by immunohistochemical assay supported those determined by extraction assays. However, among premenopausal patients, trial conclusions drawn from PgR status differed--immunohistochemically determined PgR status could predict response to endocrine therapy, unlike that determined by the extraction assay.

Quality in emergency departments: a study on 3,285,440 admissions

INTRODUCTION: A multi-centre study has been conducted, during 2005, by means of a questionnaire posted on the Italian Society of Emergency Medicine (SIMEU) web page. Our intention was to carry out an organisational and functional analysis of Italian Emergency Departments (ED) in order to pick out some macro-indicators of the activities performed. Participation was good, in that 69 ED (3,285,440 admissions to emergency services) responded to the questionnaire. METHODS: The study was based on 18 questions: 3 regarding the personnel of the ED, 2 regarding organisational and functional aspects, 5 on the activity of the ED, 7 on triage and 1 on the assessment of the quality perceived by the users of the ED. RESULTS AND CONCLUSION: The replies revealed that 91.30% of the ED were equipped with data-processing software, which, in 96.83% of cases, tracked the entire itinerary of the patient. About 48,000 patients/year used the ED: 76.72% were discharged and 18.31% were hospitalised. Observation Units were active in 81.16% of the ED examined. Triage programmes were in place in 92.75% of ED: in 75.81% of these, triage was performed throughout the entire itinerary of the patient; in 16.13% it was performed only symptom-based, and in 8.06% only on-call. Of the patients arriving at the ED, 24.19% were assigned a non-urgent triage code, 60.01% a urgent code, 14.30% a emergent code and 1.49% a life-threatening code. Waiting times were: 52.39 min for non-urgent patients, 40.26 min for urgent, 12.08 for emergent, and 1.19 for life-threatening patients.

Prognostic value of PCSK9 levels in patients with acute coronary syndromes.

AIMS Proprotein convertase subtilisin kexin 9 (PCSK9) is an emerging target for the treatment of hypercholesterolaemia, but the clinical utility of PCSK9 levels to guide treatment is unknown. We aimed to prospectively assess the prognostic value of plasma PCSK9 levels in patients with acute coronary syndromes (ACS). METHODS AND RESULTS Plasma PCSK9 levels were measured in 2030 ACS patients undergoing coronary angiography in a Swiss prospective cohort. At 1 year, the association between PCSK9 tertiles and all-cause death was assessed adjusting for the Global Registry of Acute Coronary Events (GRACE) variables, as well as the achievement of LDL cholesterol targets of <1.8 mmol/L. Patients with higher PCSK9 levels at angiography were more likely to have clinical familial hypercholesterolaemia (rate ratio, RR 1.21, 95% confidence interval, CI 1.09-1.53), be treated with lipid-lowering therapy (RR 1.46, 95% CI 1.30-1.63), present with longer time interval of chest pain (RR 1.29, 95% CI 1.09-1.53) and higher C-reactive protein levels (RR 1.22, 95% CI 1.16-1.30). PCSK9 increased 12-24 h after ACS (374 ± 149 vs. 323 ± 134 ng/mL, P < 0.001). At 1 year follow-up, HRs for upper vs. lower PCSK9-level tertiles were 1.13 (95% CI 0.69-1.85) for all-cause death and remained similar after adjustment for the GRACE score. Patients with higher PCSK9 levels were less likely to reach the recommended LDL cholesterol targets (RR 0.81, 95% CI 0.66-0.99). CONCLUSION In ACS patients, high initial PCSK9 plasma levels were associated with inflammation in the acute phase and hypercholesterolaemia, but did not predict mortality at 1 year.

Con las mejores intenciones... : Estudio sobre las prácticas políticas de los jóvenes estudiantes en la actual escuela secundaria obligatoria, en un contexto de fragmentación social

Este trabajo de investigación se ha propuesto indagar y comprender las prácticas asociadas con la construcción de una ciudadanía activa y participativa que desarrollan los jóvenes estudiantes en las escuelas secundarias seleccionadas, en la ciudad de Olavarría, durante el período 2009-2011. Iniciado un proceso de reposicionamiento estatal, la Ley de Educación Nacional No 26.206 deposita en la escuela sus expectativas de formación de una ciudadanía activa, construida sobre la base jurídica de "igualdad de derechos". Las escuelas, como parte de un sistema educativo fragmentado, tienen serias dificultades para instituir normas democráticas e igualitarias en el marco del escenario social contemporáneo. En su interior se desarrollan prácticas sociales que revelan la contingencia de lo social caracterizado por la desigualdad y la fragmentación, situación que genera, para los jóvenes, diversas y desiguales posibilidades de producir acciones orientadas a la convivencia, la participación y la generación de demandas ante situaciones de conflictos irresueltos. El formato del curriculum escolar, que mantiene en su desarrollo el peso de la historia de la escuela secundaria tradicional, pareciera, por momentos, constituirse en un obstáculo para sostener las nuevas relaciones pedagógicas y sociales necesarias para educar a los jóvenes como sujetos políticos. Ya sea para comprender las disposiciones de los jóvenes como también la propuesta de la nueva LEN es preciso indicar que -a pesar de los nuevos aires democratizantes que surcan el cono sur del continente- sigue siendo necesario reflexionar sobre las nuevas formas de construcción de hegemonía neoliberal, de acuerdo con los posicionamientos que marcan reconocidos referentes de la Pedagogía Crítica (Apple, Torres, entre otros)

Con las mejores intenciones... : Estudio sobre las prácticas políticas de los jóvenes estudiantes en la actual escuela secundaria obligatoria, en un contexto de fragmentación social

Este trabajo de investigación se ha propuesto indagar y comprender las prácticas asociadas con la construcción de una ciudadanía activa y participativa que desarrollan los jóvenes estudiantes en las escuelas secundarias seleccionadas, en la ciudad de Olavarría, durante el período 2009-2011. Iniciado un proceso de reposicionamiento estatal, la Ley de Educación Nacional No 26.206 deposita en la escuela sus expectativas de formación de una ciudadanía activa, construida sobre la base jurídica de "igualdad de derechos". Las escuelas, como parte de un sistema educativo fragmentado, tienen serias dificultades para instituir normas democráticas e igualitarias en el marco del escenario social contemporáneo. En su interior se desarrollan prácticas sociales que revelan la contingencia de lo social caracterizado por la desigualdad y la fragmentación, situación que genera, para los jóvenes, diversas y desiguales posibilidades de producir acciones orientadas a la convivencia, la participación y la generación de demandas ante situaciones de conflictos irresueltos. El formato del curriculum escolar, que mantiene en su desarrollo el peso de la historia de la escuela secundaria tradicional, pareciera, por momentos, constituirse en un obstáculo para sostener las nuevas relaciones pedagógicas y sociales necesarias para educar a los jóvenes como sujetos políticos. Ya sea para comprender las disposiciones de los jóvenes como también la propuesta de la nueva LEN es preciso indicar que -a pesar de los nuevos aires democratizantes que surcan el cono sur del continente- sigue siendo necesario reflexionar sobre las nuevas formas de construcción de hegemonía neoliberal, de acuerdo con los posicionamientos que marcan reconocidos referentes de la Pedagogía Crítica (Apple, Torres, entre otros)