Studio del microcircolo della parete gastrica affetta da patologia infiammatoria e neoplastica mediante Color-Power Doppler ed ecografia con mezzo di contrasto endovenoso

Introduzione: Negli ultimi anni, il color-power Doppler si è dimostrato un utile strumento per valutare le alterazioni della vascolarizzazione della parete intestinale nelle patologie del tratto gastro-enterico. Più di recente, i mezzi di contrasto ecografici di II generazione associati all’ecografia real-time con basso indice meccanico (CEUS) hanno permesso di valutare ecograficamente il microcircolo, consentendo la valutazione della vascolarizzazione di parete nelle patologie associate a flogosi e neoangiogenesi. Studi recenti hanno documentato i pattern Doppler e CEUS nella malattia infiammatoria intestinale. Le alterazioni della vascolarizzazione di parete nella patologia neoplastica, invece, sono state finora valutate con sola tecnica Doppler. Recenti studi basati sull’impiego di tale metodica hanno in effetti dimostrato che l’intensità del segnale vascolare di parete correla con la variante istologica della neoplasia e con il suo grado di invasione vascolare costituendo così un parametro di neoangiogenesi tumorale. Pertanto, ottenere mediante CEUS una più accurata definizione del microcircolo di parete potrebbe aiutare nella diagnosi differenziale tra patologia infiammatoria e neoplastica dello stomaco e fornire utili informazioni per valutare l’ aggressività del cancro gastrico.

Circoli collaterali porto-sistemici all'eco-color-Doppler addominale in pazienti con ipertensione portale cirrotica: correlazione con il gradiente porto-epatico e valore prognostico

Background. Abdominal porto-systemic collaterals (APSC) on Color-Doppler ultrasound are a frequent finding in portal hypertensive cirrhotic patients. In patients with cirrhosis, an HVPG ≥ 16mmHg has been shown to be associated with increased mortality in two studies. Non-invasive indicators of HVPG ≥ 16 mmHg might define a subgroup of high-risk patients, but data on this aspect are lacking. Aims. We aimed to investigate whether HVPG predicts mortality in patients with clinically significant portal hypertension, and if APSC may predict a severe portal hypertensive state (i.e. HVPG≥16mmHg) in patients with cirrhosis and untreated portal hypertension. Methods. We analysed paired HVPG and ultrasonographic data of 86 untreated portal hypertensive cirrhotic patients. On abdominal echo-color-Doppler data on presence, type and number of APSC were prospectively collected. HVPG was measured following published guidelines. Clinical, laboratory and endoscopic data were available in all cases. First decompensation of cirrhosis and liver-disease related mortality on follow-up (mean 28±20 months) were recorded. Results. 73% of patients had compensated cirrhosis, while 27% were decompensated. All patients had an HVPG≥10 mmHg (mean 17.8±5.1 mmHg). 58% of compensated patients and 82% of decompensated patients had an HVPG over 16 mmHg. 25% had no varices, 28% had small varices, and 47% had medium/large varices. HVPG was higher in patients with esophageal varices vs. patients without varices (19.0±4.8 vs. 14.1±4.2mmHg, p<0.0001), and correlated with Child-Pugh score (R=0.494,p=0.019). 36 (42%) patients had APSC were more frequent in decompensated patients (60% vs. 35%, p=0.03) and in patients with esophageal varices (52% vs. 9%,p=0.001). HVPG was higher in patients with APSC compared with those without PSC (19.9± 4.6 vs. 16.2± 4.9mmHg, p=0.001). The prevalence of APSC was higher in patients with HVPG≥16mmHg vs. those with HVPG<16mmHg (57% vs. 13%,p<0.0001). Decompensation was significantly more frequent in patients with HVPG≥16mmHg vs. HVPG<16mmHg (35.1% vs. 11.5%, p=0.02). On multivariate analysis only HVPG and bilirubin were independent predictors of first decompensation. 10 patients died during follow-up. All had an HVPG≥16 mmHg (26% vs. 0% in patients with HVPG <16mmHg,p=0.04). On multivariate analysis only MELD score and HVPG ≥16mmHg were independent predictors of mortality. In compensated patients the detection of APSC predicted an HVPG≥16mmHg with 92% specificity, 54% sensitivity, positive and negative likelihood ratio 7.03 and 0.50, which implies that the demonstration of APSC on ultrasound increased the probability of HVPG≥16mmHg from 58% to 91%. Conclusions. HVPG maintains an independent prognostic value in the subset of patients with cirrhosis and clinically significant portal hypertension. The presence of APSC is a specific indicator of severe portal hypertension in patients with cirrhosis. Detection of APSC on ultrasound allows the non-invasive identification of a subgroup of compensated patients with bad prognosis, avoiding the invasive measurement of HVPG.

Color/kinematic duality, double copies and scalar matrix models

In questa tesi presentiamo una descrizione autoconsistente della dualità Colore/Cinematica nelle teorie di gauge e al processo di Double Copy. Particolare attenzione viene data all'approccio alla dualità con il formalismo di cono-luce, in quanto semplifica notevolmente sia il calcolo sia l'interpretazione fisica: vengono indagati i settori duale e self-duale per poi passare al modello di Chalmers e Siegel per l'estensione alla teoria generale. Proponiamo quindi uno Scalar Matrix Model, che può essere un buon modello per generare ampiezze ottenibili da una Double Copy `inversa', e ne studiamo un'eventuale dualità a la Colore/Cinematica. Vengono illustrati alcuni casi particolari di rottura spontanea di simmetria. In appendice riportiamo un notebook di Mathematica per il calcolo di ampiezze tree level di puro gauge, utile per i calcoli necessari allo studio della dualità.

Characterization of the genetic control of fruit flesh color in peach

The analysis of a carotenoid cleavage dioxygenase gene in a pool of peach cultivars revealed the existence of a functional allele (W1), associated with the white flesh trait, and three independent mutations associated with the yellow phenotype: a 2 bp insertion within a repetitive sequence (y1), a large transposable element within the intron (y2) and a single base substitution generating a premature stop codon (y3). Based on these evidences, the yellow flesh phenotype seems to have arisen from at least three independent mutational events.

New design of polyphenylene dendrimers for full-color light-emitting diodes

Dendritic systems, and in particular polyphenylene dendrimers, have recently attracted considerable attention from the synthetic organic chemistry community, as well as from photophysicists, particularly in view of the search for synthetic model analogies to photoelectric materials to fabricate organic light-emitting diodes (OLEDs), and even more advanced areas of research such as light-harvesting system, energy transfer and non-host device. Geometrically, dendrimers are unique systems that consist of a core, one or more dendrons, and surface groups. The different parts of the macromolecule can be selected to give the desired optoelectronic and processing properties. Compared to small molecular or polymeric light-emitting materials, these dendritic materials can combine the benefits of both previous classes. The high molecular weights of these dendritic macromolecules, as well as the surface groups often attached to the distal ends of the dendrons, can improve the solution processability, and thus can be deposited from solution by simple processes such as spin-coating and ink-jet printing. Moreover, even better than the traditional polymeric light-emitting materials, the well-defined monodisperse distributed dendrimers possess a high purity comparable to that of small molecules, and as such can be fabricated into high performance OLEDs. Most importantly, the emissive chromophores can be located at the core of the dendrimer, within the dendrons, and/or at the surface of the dendrimers because of their unique dendritic architectures. The different parts of the macromolecule can be selected to give the desired optoelectronic and processing properties. Therefore, the main goals of this thesis are the design and synthesis, characterization of novel functional dendrimers, e.g. polytriphenylene dendrimers for blue fluorescent, as well as iridium(III) complex cored polyphenylene dendrimers for green and red phosphorescent light emitting diodes. In additional to the above mentioned advantages of dendrimer based OLEDs, the modular molecular architecture and various functionalized units at different locations in polyphenylene dendrimers open up a tremendous scope for tuning a wide range of properties in addition to color, such as intermolecular interactions, charge mobility, quantum yield, and exciton diffusion. In conclusion, research into dendrimer containing OLEDs combines fundamental aspects of organic semiconductor physics, novel and highly sophisticated organic synthetic chemistry and elaborate device technology.rn

Frequency-dependent social dominance in a color polymorphic cichlid fish

A mechanism commonly suggested to explain the persistence of color polymorphisms in animals is negative frequency-dependent selection. It could result from a social dominance advantage to rare morphs. We tested for this in males of red and blue color morphs of the Lake Victoria cichlid, Pundamilia. Earlier work has shown that males preferentially attack the males of their own morph, while red males are more likely to win dyadic contests with blue males. In order to study the potential contribution of both factors to the morph co-existence, we manipulated the proportion of red and blue males in experimental assemblages and studied its effect on social dominance. We then tried to disentangle the effects of the own-morph attack bias and social dominance of red using simulations. In the experiment, we found that red males were indeed socially dominant to the blue ones, but only when rare. However, blue males were not socially dominant when rare. The simulation results suggest that an own-morph attack bias reduces the social dominance of red males when they are more abundant. Thus, there is no evidence of symmetric negative frequency-dependent selection acting on social dominance, suggesting that additional fitness costs to the red morph must explain their co-existence.

America's Shifting Color Line? Reexamining Determinants of Latino Racial Self-Identification

Objectives. Latinos are the nation's largest minority group and will double in size by 2050. Their size coupled with the fact that Latinos do not constitute a separate race raises questions about Latinos' incorporation into the U. S. racial hierarchy. This article explores patterns of Latino racial identity formation, examining the determinants of racial identity. Methods. Using the 2006 Latino National Survey, I estimate multinomial logit and ordered probit models of identification choices. Results. Latino racial identity is strongly associated with several factors, including socioeconomic status, measures of perceived discrimination and commonality, and measures of acculturation/assimilation. Most Latinos have a broader, more complex understanding of race. Furthermore, some Latinos do believe that they occupy a unique position in the racial hierarchy. Conclusions. The results suggest that the color line W. E. DuBois argued has long divided our nation may eventually shift.

An Ethical History of Photography in Combat and of Combat Photography in the United States during World War II

With the United States‘ entry into the Second World War, the word ?censorship? was seen largely as antithetical to, rather than a necessary counterpart to, victory among Americans. People did not want to be censored in their writing, photographs or speech,but it proved to be necessary even before the war began, in order to protect government secrets and the people on the home-front from scenes that were too disturbing. Even before the war had officially begun, there were problems with censorship among journalists and newspapers. The initial response of outrage in reference to censorship in the United States was common among journalists, newspapers, magazines, and radio news; nevertheless, there was a necessity for censorship among Americans, on the home frontand the front lines, and it would be tolerated throughout the war to ensure that enemies of America did not gain access to information that would assist in a defeat of the United States in the Second World War. The research I have conducted has dealt with the censorship of combat photography during World War II, in conjunction with the ethics that were in play at the time that affected the censors. Through exploring the work of three combat photographers — Tony Vaccaro, James R. Stephens and Charles E. Sumners — I wasable to effectively construct an explanatory ethical history of these three men. Research on the censorship and effects it had on the United States brought me to three distinctareas of censorship and ethics that would be explored: (1) the restrictions and limitations enforced by the Office of Censorship, (2) a general overview of war and photography as it influenced the soldiers and their families on the home-front, (3) and the combat photographers and personal and military censorship that influenced their work. Although their work was censored both by the military and the government, these men saw the war in a different light that remained with them long after the battles and war had ceased.Using the narratives of Tony Vaccaro, Charles E. Sumners and James R. Stephens as means for more in depth research, this thesis strives to create lenses through which to view the history and ethics of censorship that shaped combat photography during the Second World War and the images to which we refer as representative of that war today.