1,721,123 research outputs found
An improved device for conversion of mechanical energy from sea waves to electric energy
No full textDevice for converting mechanical energy from sea waves into electric energy including at least a float and two rigid rods. The rods are preferably anchored to the seabed at one end, and to the float at another end. There are also two ballasts that effect their weight towards the sea bed to keep the free ends of the rods constantly in traction and free to rotate around their hinges. The float oscillates up and down along a vertical line due to waves. There are at least two cables that connect the free ends of the rods to a transmission shaft of a generator positioned along the vertical line so that the vertical, horizontal, or rotary oscillatory motion of the float caused by the waves generates an oscillatory motion of the rods which are pivoted on their respective hinges, and thus transfers rotary motion to the transmission shaft of the generator
The influence of depth limited water conditions on the rock slope stability
Full text linkThe hydraulic stability of the armour layer of the rubble mound breakwaters have been widely discussed in the literature and
several empirical formulas have been proposed for design purposes. Nevertheless, few studies focused on the armour
stability in case of water depth limited water conditions.Then, the aim of the present research is to provide more
insights into the stability of the armour layer ranging from intermediate till extremely shallow water conditions. To this end, a 2D physical experiments have been carried out at the EUropean Maritime and Environmental Research (EUMER) laboratory of the University of Salento (Lecce), in presence of a 1V:30H foreshore. Tests aimed to investigate both the nearshore hydrodynamics and the hydraulic armour stability under different irregular waves attack. Experimental results are also compared with the damage evaluated from the empirical formulations available in literature, in order to investigate the predicted damage level in the shallowness
range analyzed
3D numerical modeling of landslide-generated tsunamis around a conical island
No full textThis paper presents numerical computations of tsunamis generated by landslides falling along the flank of a conical island. The model used is the fully three-dimensional commercial code FLOW-3D, based on the VOF technique for the treatment of the free surface. The model results are compared against available experimental data that allow validation of the model, evaluation of its accuracy, and estimation of the computational costs. The main conclusion of this research is that the model is applicable at reasonable costs for a few accurate simulations that may be used for preparing precomputed inundation maps of coasts prone to the risk of tsunamis inundation
Colorectal adenoma-carcinoma. Guidelines and minimal diagnostic criteria. Italian Group for Pathology of the Digestive System.
No full textno abstrac
Adenoma-carcinoma del retto-colon. Linee guida e criteri diagnostici minimi.
No full textIl carcinoma del retto-colon (CRC) è la terza forma tumorale per frequenza e la seconda causa di morte
per neoplasia in molti Paesi occidentali. In Italia, l'incidenza annua é stimata intorno a 20-30 mila nuovi
casi. La storia naturale è fortemente condizionata dallo stadio di malattia. Il CRC é infatti un tumore
con elevata percentuale di guarigione quando ancora limitato alla parete del viscere, mentre diventa
altamente letale, e la sua progressione poco controllabile con la terapia, quando supera i confini della
parete e metastatizza ai linfonodi.
Il CRC prende origine, in oltre il 90% dei casi, da un precursore focale, displastico, polipoide:
l'adenoma o polipo adenomatoso(19). Tale tipo di progressione tumorale, conosciuto come sequenza
adenoma-carcinoma, ha trovato riscontro e validazione clinica ed epidemiologica. Il tasso di
trasformazione maligna degli adenomi è di 2,5 adenomi per 1.000 per anno, con un tempo stimato,
particolarmente per gli adenomi <1 cm, di 10-15 anni: la tempestiva asportazione degli adenomi si è
dimostrata efficace nel ridurre l'incidenza del CRC(27). In una piccola percentuale di casi (5-10%),
soprattutto del colon destro, il carcinoma sembra non essere preceduto da lesioni polipoidi (c.d.
"carcinoma de novo").
E' acquisito che la tumorigenesi colorettale implica l'accumulo sequenziale di mutazioni di oncogeni e
di geni soppressori tumorali (Apc, Ras, DCC, MCC, p53..), eventualmente accelerato da alterazioni dei
meccanismi molecolari che normalmente controllano la stabilità del genoma (geni hMSH2, hMLH1,
hPMS1, h PMS2). Ogni evento mutazionale è in grado di orientare la storia naturale ed anche la
morfogenesi della neoplasia, sicchè alcuni di essi possono essere impiegati come marcatori prognostici
e/o essere correlati con specifiche caratteristiche morfologiche(1, 20, 25), ma le procedure di
validazione sono tutt'ora in corso e l'impiego routinario di tecniche di Patologia Molecolare
relativamente limitato
L'effetto dei natanti ormeggiati sui profili di rigurgito delle correnti a superficie libera
No full textLo sviluppo della portualità turistica in zone fortemente antropizzate e di grande valenza paesaggistica, come nel caso dell’Italia, richiede estrema attenzione nella scelta dei siti idonei ad ospitare nuove strutture per l’ormeggio dei natanti. I tratti terminali di alvei fluviali, sia principali che minori, sia naturali che regolarizzati, rappresentano spesso delle alternative di localizzazione in virtù del riparo naturale dal moto ondoso e dalla facilità di accesso dalle sponde. Si propone una metodologia atta a stimare quantitativamente l’azione dei natanti ormeggiati sull’andamento dei profili di rigurgito negli alvei fluviali. Secondo tale metodologia la presenza dei natanti può essere schematizzata come un incremento della scabrezza dell’alveo; in tal modo si possono utilizzare i metodi per il tracciamento dei profili di rigurgito con un coefficiente di resistenza opportunamente variato. I risultati teorici ottenuti sono confermati dall’evidenza sperimentale di un’indagine appositamente realizzata su modello fisico
Effects of moored boats on the gradually varied free-surface profiles of river flows
No full textThe last mile of rivers often represents an option worth considering for the development of ports. This is particularly true in coastal areas that are densely developed. The simplest form of a port canal, i.e., boats moored along the banks, is an attractive option for the low investment required and the often acceptable residual wave motion. Some of the major rivers have thousands of boats moored along their banks. The effect of these floaters on the river levels during floods must be taken into account. The authors present a methodology based on the computation of the forces on a single boat or an array of boats that yields a quantification of the effect on the river levels. It essentially provides an iterative procedure for computing the value of the resistance coefficient to be used in hydraulic analysis. Theoretical predictions are satisfactorily confirmed by ad hoc experimental investigation
Oxidative DNA damage drives carcinogenesis in MUTYH-associated-polyposis by specific mutations of mitochondrial and MAPK genes.
No full textMUTYH is a DNA-base-excision-repair gene implicated in the activation of nuclear and mitochondrial cell-death pathways. MUTYH germline mutations cause an inherited polyposis, MUTYH-associated-polyposis, characterized by multiple adenomas and increased susceptibility to colorectal cancer. Since this carcinogenesis remains partially unknown, we searched for nuclear and mitochondrial gene alterations that may drive the tumorigenic process. Ninety-six adenomas and 7 carcinomas from 12 MUTYH-associated-polyposis and 13 classical/attenuated adenomatous polyposis patients were investigated by sequencing and pyrosequencing for the presence of mutations in KRAS, BRAF, MT-CO1/MT-CO2 and MT-TD genes. KRAS mutations were identified in 24% MUTYH-associated-polyposis vs 15% classical/attenuated familial polyposis adenomas; mutated MUTYH-associated-polyposis adenomas exhibited only c.34G>T transversions in codon 12, an alteration typically associated with oxidative DNA damage, or mutations in codon 13; neither of these mutations was found in classical/attenuated familial polyposis adenomas (PT transversions, prevalently occurring with BRAFV600E; none of the classical/attenuated familial polyposis carcinomas displayed these alterations. Comparing mitochondrial DNA from lymphocytes and adenomas of the same individuals, we detected variants in 82% MUTYH-associated-polyposis vs 38% classical/attenuated familial polyposis patients (P=0.040). MT-CO1/MT-CO2 missense mutations, which cause aminoacid changes, were only found in MUTYH-associated-polyposis lesions and were significantly associated with KRAS mutations (P=0.0085). We provide evidence that MUTYH-associated-polyposis carcinogenesis is characterized by the occurrence of specific mutations in both KRAS and phylogenetically conserved genes of mitochondrial DNA which are involved in controlling oxidative phosphorylation; this implies the existence of a colorectal tumorigenesis in which changes in mitochondrial functions cooperate with RAS-induced malignant transformation
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