Thermal boundary resistance from transient nanocalorimetry: a multiscale modeling approach

The Thermal Boundary Resistance at the interface between a nanosized Al film and an Al_{2}O_{3} substrate is investigated at an atomistic level. A room temperature value of 1.4 m^{2}K/GW is found. The thermal dynamics occurring in time-resolved thermo-reflectance experiments is then modelled via macro-physics equations upon insertion of the materials parameters obtained from atomistic simulations. Electrons and phonons non-equilibrium and spatio-temporal temperatures inhomo- geneities are found to persist up to the nanosecond time scale. These results question the validity of the commonly adopted lumped thermal capacitance model in interpreting transient nanocalorimetry experiments. The strategy adopted in the literature to extract the Thermal Boundary Resistance from transient reflectivity traces is revised at the light of the present findings. The results are of relevance beyond the specific system, the physical picture being general and readily extendable to other heterojunctions.Comment: 12 pages, 8 figure

Il trapianto di rene da donatore anziano: "a tailored approach"

In questo studio sono stati analizzati i risultati di 275 trapianti di rene eseguiti da donatori ultrasessantenni sia viventi che cadavere, dal Gennaio 2000 al Dicembre 2012 presso il reparto di Chirurgia Generale e dei Trapianti dell’Università degli Studi di Pisa, con un follow-up massimo di 120 mesi. Abbiamo, inoltre, eseguito dei confronti tra i risultati dei trapianti nelle seguenti sottopopolazioni: - CKT (Cadaveric donors Kidney Transplant; 226 tx) vs LKT (Living donors Kidney Transplant; 49); - SKT (Single Kidney Transplant; 137 tx) vs DKT (Dual Kidney Transplant; 89 tx); - Trapianti effettuati dopo biopsia (183 tx) vs trapianti effettuati senza biopsia (83 tx); - SKT con score bioptico di 4-5 (42 tx) vs DKT con score bioptico di 4-5 (48 tx); - SKT con score bioptico di 4-5 (42 tx) vs SKT con score bioptico inferiore o uguale a 3 (48 tx). La selezione del donatore vivente è stata effettuata sulla base di criteri clinici, di imaging e tramite la valutazione del filtrato renale ottenuto mediante scintigrafia renale. Abbiamo, invece, basato la nostra scelta di utilizzare il rene del donatore cadavere non solo sulla base delle caratteristiche cliniche del donatore (età, BMI, diabete, ipertensione, funzione renale, CMV IgG+) e dello score bioptico del graft pre-trapianto secondo Karpinski (quando è stata effettuata la biopsia) ma anche analizzando attentamente in ogni singolo caso le caratteristiche del ricevente (età, BMI, mesi dialisi pre-trapianto, CMV IgG+) per ottenere il miglior “match” possibile donatore-ricevente. I nostri risultati mostrano, in pieno accordo con la letteratura, che la sopravvivenza del graft e del paziente sia migliore nel gruppo LKT rispetto al gruppo CKT (graft: 92,12% vs 61,59% p=0,004; paziente: 92,12% vs 74,25% p=0,05 paziente). Confrontando, invece, i gruppi SKT e DKT, che risultano omogenei per le principali caratteristiche generali, abbiamo visto come non vi siano differenze statisticamente significative tra i due gruppi in termini di sopravvivenza del graft (55,64% vs 74,82%, p=NS) e del paziente (71,29% vs 80,96%, p=NS). La popolazione dei riceventi un trapianto dopo esecuzione di biopsia pre-trapianto per l’allocazione dell’organo non presenta un miglior outcome di quella in cui non è stata eseguita la biopsia (sopravvivenza del graft: 63,10% vs 56,81% p=NS; sopravvivenza del paziente: 78,12% vs 64,56% p=NS). Risultati interessanti derivano dall’analisi del confronto tra i gruppi SKT 4-5 vs DKT 4-5 e SKT 4-5 vs SKT ≤ 3. In entrambi i confronti non abbiamo riscontrato differenze statisticamente significative per sopravvivenza del graft (SKT 4-5 56,83% vs DKT 4-5 63,10%; SKT 4-5 56,83% vs SKT ≤ 3 50,5%) e del paziente (SKT 4-5 86,31% vs DKT 4-5 86,20%; SKT 4-5 86,31% vs SKT ≤ 3 66,30%). Questi dati sembrano avvalorare il nostro approccio circa la possibilità di eseguire trapianti singoli anche con score bioptico secondo Karpinski di 4 o 5, grazie ad una accurata selezione della coppia donatore-ricevente. In questo modo si riuscirebbe a garantire il trapianto di rene ad un maggior numero di pazienti in lista di attesa per trapianto; questo aspetto, in accordo con la letteratura internazionale, porterebbe direttamente ad un allungamento della sopravvivenza e ad un miglioramento della qualità di vita di questi pazienti. Nel caso del donatore cadavere ultrasessantenne, quindi, un’attenta valutazione dei parametri clinici, accompagnata dalla valutazione istopatologica del rene, quando necessaria, permette di raggiungere buoni risultati anche a lungo termine per quanto riguarda sopravvivenza del graft e del paziente. Questo approccio sembra essere una valida risposta alla carenza di organi, all’invecchiamento della popolazione dei donatori e al sovraffollamento delle liste d’attesa

The use of x-ray CT and MRI in the study of sacroiliac joints in patients with Behcet disease and acute anterior uveitis

Objective: It's controversial if Behcet Disease (BD) must be included in the group of seronegative spondyloarthropathy (SpA). Our aim was to establish the prevalence of sacroiliitis (SI) in patients with BD using X-Ray, CT and MRI, in comparison with patients with Acute Anterior Uveitis (AAU), that is known to belong to the subgroups of SpA. Methods: We considered, in the period from 04/2006 to 04/2009, 21 consecutive patients with BD, positive for HLA B51 and 28 consecutive patients with AAU, positive for HLA B27. These patients were previously selected by our Rheumatological Ward. Altogether we evaluated 98 sacroiliac joints (SIJ); each side of any patient was graded separately. Results: X-ray of the pelvis showed advanced SI (grade 4) in 14% of the cases in patients with AAU; in BD group only 7% CT showed advanced SI in 14% within AAU patients versus 6-12% of advanced SI (right to left) within BD patients. MR showed 14% of advanced SI (bilateral) within AAU versus 6-11% of advanced SI (right to left) in BD patients. Conclusions: This study supports the trend to not consider BD within the SpA, being the prevalence of SI in BD patients not very different from general population and anyway lower than that observed in patients with AAU. On the other side the prevalence of SI in AAU patients is higher than in BD patients and very similar to the one observed in patients with seronegative arthritis, and anyway high enough to consider joint involvement as an important feature of the disease

Memory effects in stock price dynamics: evidences of technical trading

Technical trading represents a class of investment strategies for Financial Markets based on the analysis of trends and recurrent patterns in price time series. According standard economical theories these strategies should not be used because they cannot be profitable. On the contrary, it is well-known that technical traders exist and operate on different time scales. In this paper we investigate if technical trading produces detectable signals in price time series and if some kind of memory effects are introduced in the price dynamics. In particular, we focus on a specific figure called supports and resistances. We first develop a criterion to detect the potential values of supports and resistances. Then we show that memory effects in the price dynamics are associated to these selected values. In fact we show that prices more likely re-bounce than cross these values. Such an effect is a quantitative evidence of the so-called self-fulfilling prophecy, that is the self-reinforcement of agents' belief and sentiment about future stock prices' behavior

Growth Charts for Height,Weight, and BMI (6–18 y) for the Tuscany Youth Sports Population

Overweight during youth is a large-scale public health issue. Engaging in regular physical activity generally reduces weight status. The hypothesis of the study is that organized sport plays an active role in maintaining a correct body weight during youth. The purpose of this study is to trace growth charts by height, weight, and body mass index (BMI) to be applied to the youth sports population. A retrospective study was conducted on 14,700 young athletes (10,469 males and 4231 females) aged between 6 and 18 years from surveillance carried out during the pre-participation screening of sports eligibility. The calculation of the prevalence of overweight and obesity was also performed. The new percentiles for the youth sports population show BMI values at 18 years 21.9 kg/m2 for males and 20.7 kg/m2 for females at the 50th percentile. The male sample shows 12.3% of the subjects were overweight and 1.5% were obese, while the female sample shows 9.8% are overweight and 1.1% obese. The higher prevalence of excess weight is evident up to 12 years old in both sexes and then gradually decreases. The development of the new specific growth charts for the youth sports population could reduce the risk of error in identifying the correct weight status of young athletes

Micro-structured rough surfaces by laser etching for heat transfer enhancement on flush mounted heat sinks

Abstract. The aim of this work is to improve heat transfer performances of ush mounted heat sinks used in electronic cooling. To do this we patterned 1.23 cm2 heat sinks surfaces by micro- structured roughnesses built by laser etching manufacturing technique, and experimentally measured the convective heat transfer enhancements due to dierent patterns. Each roughness diers from the others with regards to the number and the size of the micro-ns (e.g. the micro- n length ranges from 200 to 1100 m). Experimental tests were carried out in forced air cooling regime. In particular fully turbulent ows (heating edge based Reynolds number ranging from 3000 to 17000) were explored. Convective heat transfer coecient of the best micro-structured heat sink is found to be roughly two times compared to the smooth heat sinks one. In addition, surface area roughly doubles with regard to smooth heat sinks, due to the presence of micro-ns. Consequently, patterned heat sinks thermal transmittance [W/K] is found to be roughly four times the smooth heat sinks one. We hope this work may open the way for huge boost in the technology of electronic cooling by innovative manufacturing techniques

Lactate as a marker of energy failure in critically ill patients: hypothesis

Lactate measurement in the critically ill has been traditionally used to stratify patients with poor outcome. However, plasma lactate levels are the result of a finely tuned interplay of factors that affect the balance between its production and its clearance. When the oxygen supply does not match its consumption, organisms such as man who are forced to produce ATP for their integrity adapt in many different ways up to the point when energy failure occurs. Lactate, being part of the adaptive response, may then be used to assess the severity of the supply/demand imbalance. In such a scenario, the time to intervention becomes relevant: early and effective treatment may allow the cell to revert to a normal state, as long as the oxygen machinery (i.e. mithocondria) is intact. Conversely, once the mithocondria are deranged, energy failure occurs even in the presence of normoxia. The lactate increase in critically ill patients may therefore be viewed as an early marker of a potentially reversible state

Leganti monodentati a chiralità assiale in catalisi asimmetrica

La evidente somiglianza strutturale tra il leganti 1-3 e la binaftofosfepina 5, un legante monodentato con un fosforo fortemente elettron donatore e quindi più idoneo all’ottenimento di catalizzatori di idrogenazione di elevata attività catalitica, ci ha spinto ad indagare il comportamento di 5 nell’idrogenazione asimmetrica di olefine con catalizzatori di rodio

É POSSÍVEL EDUCAR PARA AS RELAÇÕES RACIAIS? ANALISAMOS AS POSSIBILIDADES PEDAGÓGICAS EM UM CURSO SUPERIOR DE GESTÃO

The article presents the results of a research that aimed to analyze the pedagogical practices used in a Higher Course in Technology in Management Processes at a Campus of the Federal Institute of Education, Science and Technology of Rio Grande do Sul (IFRS) with a view to relations racial. A structured questionnaire was prepared and submitted to the 11 professors of the course using the Google Forms tool. The theme is of importance in the light of Law nº 10.639/2003, and its addenda, which makes the theme “Afro-Brazilian History and Culture” compulsory in the official curriculum of the education network. The results found show that the current legislation has a fundamental role in the affirmation of marginalized sectors, and, also, the lack of knowledge on the part of the teachers about the legislation in force. We highlight the relevance of the affirmative actions of the Campus of Afro-Brazilian and Indigenous Studies (NEABI) of the Campus and the need for continued teacher training on the theme. Finally, even if Law No. 10,639/2003 only covers Elementary and Secondary Education - Resolution No. 1 (CNE/CP, 2014) extends to Higher Education - we believe it is necessary to discuss the racial theme in all school spheres.El artículo presenta los resultados de una investigación que tuvo como objetivo analizar las prácticas pedagógicas utilizadas en un Curso Superior de Tecnología en Procesos de Gestión en un Campus del Instituto Federal de Educación, Ciencia y Tecnología de Rio Grande do Sul (IFRS) con miras a relaciones raciales. Se elaboró ​​un cuestionario estructurado y se envió a los 11 profesores del curso utilizando la herramienta Google Forms. El tema es de importancia a la luz de la Ley N ° 10.639/2003, y sus adiciones, que hace obligatorio el tema “Historia y cultura afrobrasileña” en el currículo oficial de la red educativa. Los resultados encontrados muestran que la legislación actual tiene un papel fundamental en la afirmación de los sectores marginados, y, también, el desconocimiento por parte de los docentes sobre la legislación vigente. Destacamos la relevancia de las acciones afirmativas del Campus de Estudios Afrobrasileños e Indígenas (NEABI) del Campus y la necesidad de una formación continua docente sobre el tema. Finalmente, aunque la Ley N ° 10.639/2003 solo cubre la Educación Primaria y Secundaria - La Resolución N ° 1 (CNE/CP, 2014) se extiende a la Educación Superior - creemos que es necesario discutir el tema racial en todos los ámbitos escolares.O artigo apresenta os resultados de uma pesquisa que teve como objetivo analisar as práticas pedagógicas utilizadas em um Curso Superior de Tecnologia em Processos Gerenciais de um Campus do Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul (IFRS) com vistas às relações Raciais. Foi elaborado um questionário estruturado e submetido aos 11 docentes do curso utilizando a ferramenta Google Forms. O tema reveste-se de importância à luz da Lei nº 10.639/2003, e seus adendos, que torna compulsória no currículo oficial da rede de ensino a temática “História e Cultura Afro-Brasileira”. Os resultados encontrados evidenciam que a legislação vigente possui papel fundamental na afirmação de setores marginalizados, e, também, o desconhecimento de parte dos docentes sobre a legislação em vigor. Destacamos a relevância das ações afirmativas do Núcleo de Estudos Afro-Brasileiro e Indígena (NEABI) do campus e a necessidade de formação docente continuada sobre a temática. Por fim, mesmo que a Lei nº 10.639/2003 contemple apenas o Ensino Fundamental e Médio – a Resolução nº 1 (CNE/CP, 2014) estende ao Ensino Superior – entendemos ser necessário discutir a temática racial em todas as esferas escolares