Search results for "GAS"
showing 10 items of 12601 documents
Gastrointestinal Stromal Tumors (GISTs)
2021
Gastrointestinal stromal tumors (GISTs) are a group of tumors that, over the past 15 years, has emerged from a poorly understood neoplasm to a well-defined tumor entity. GISTs are highly resistant to conventional chemotherapy and, in the past, were typically managed surgically.
Advances in the endoscopic management of malignant biliary obstruction
2020
Biliary obstruction is common in pancreatobiliary malignancies and has a negative impact on the patient’s quality of life, postoperative complications, and survival rates. Particularly in the last decade, there has been enormous progress regarding the diagnostic and therapeutic options in patients with malignant biliary obstruction. Endoscopy has given a new insight in this direction and novel techniques have been developed for the better characterization and treatment of malignant strictures. We herein summarize the available data on the different endoscopic techniques, and clarify their role in the diagnosis and treatment of malignant biliary obstructive disease. Finally, we propose an al…
I tumori stromali gastrointestinali: presentazione di sei casi e revisione della letteratura
2005
Gastrointestinal stromal tumours (GISTs) represent the most common kind of mesenchymal tumours that arise from the alimentary tract. GISTs express a growth factor receptor with tyrosine kinase function, which causes cellular proliferation and resistance to apoptosis. GISTs are generally found in the stomach (40-70%), and less commonly in the small intestine, colon-rectum, esophagus and peritoneum. Clinical and instrumental diagnosis is still very difficult to make. Surgery remains the standard treatment for nonmetastatic tumours. For non resectable and metastatic tumours seems to be effective the therapy with Imatinib mesylate, a specific inhibitor of tyrosine kinase receptor (KIT). Are ong…
Gas geochemistry of shallow submarine vents in the Aegean sea (Greece)
2017
The Aegean area, which is geodynamically very active, is characterised by intense seismic activity, presence of active volcanic systems and anomalous geothermal gradients. Like other regions of intense geodynamic activity it is also characterized by extensive geogenic degassing. Gas manifestations are not only widespread on land but are also very frequent underwater. Many of these, as for example those of Milos and Santorini, are known since long time and have been previously studied although the targets were generally the hot waters or the sediments affected by the emissions (Smith and Cronan 1978, Dando et al. 1995, Price et al. 2013, Megalovassilis 2014).The present study aims at produci…
Mazā svilpja Carpodacus erythrinus sastopamību noteicošie faktori un tās prognozēšana mozaīkveida ainavā Madonas novadā
2016
Lauku putnu sugas (tai skaitā mazais svilpis) Eiropā kopš 20. gadsimta beigām līdz pat šim brīdim ir piedzīvojušas būtisku cilvēka saimnieciskās darbības ietekmi uz populācijām. Darba mērķis bija izstrādāt mazā svilpja populācijas sastopamības ierobežojošos faktorus atspoguļojušu matemātisku modeli teritorijā, kur lauksaimniecības zemes nav dominējošās, izmantojot iegūto modeli, veikt sugas sastopamības prognozēšanu pētījumu teritorijā. Pētījuma teritorijā mazā svilpja sastopamības noskaidrošanai nejauši izvēlēti parauglaukumi tika apsekoti divas līdz trīs reizes sezonā, fiksējot arī konstatēšanas varbūtību ietekmējošus mainīgos. Tika analizēta biotopu un ainavas elementu mainīgo saistība a…
Muikun (Coregonus albula) suomun kasvuun ja kasvurenkaiden muodostumiseen vaikuttavia tekijöitä
2016
Muikun kasvunopeudessa on suurta vaihtelua, mikä voi heijastua myös sen luutuvien osien rakenteeseen. Veden lämpötila vaikuttaa ravinnonottoon sekä aineenvaihduntaan ja sitä kautta myös kasvuun. Jos gametogeneesin aikana naaraiden ja koiraiden käyttäytyminen sekä energiankäyttö poikkeavat toisistaan, sukupuolten välisiä eroja voidaan mahdollisesti havaita myös suomun kasvurytmiikassa. Tämän tutkimuksen tavoitteena oli selvittää, miten kasvurenkaiden muodostuminen eroaa sukupuolten ja ikäryhmien välillä sekä millaisia vaikutuksia lämpötilan vaihteluilla on kasvurenkaiden määrään. Näytekalat saatiin Etelä-Konnevedeltä avovesikaudella 2013. Kaikilta kaloilta laskettiin suomun kasvurenkaiden lu…
Superfluid weight and Berezinskii-Kosterlitz-Thouless transition temperature of twisted bilayer graphene
2019
We study superconductivity of twisted bilayer graphene with local and non-local attractive interactions. We obtain the superfluid weight and Berezinskii-Kosterlitz-Thouless (BKT) transition temperature for microscopic tight-binding and low-energy continuum models. We predict qualitative differences between local and non-local interaction schemes which could be distinguished experimentally. In the flat band limit where the pair potential exceeds the band width we show that the superfluid weight and BKT temperature are determined by multiband processes and quantum geometry of the band.
Surfactant self-assembling in the gas phase: bis(2-ethylhexyl)- sulfosuccinate divalent metal ion anionic aggregates
2012
RATIONALE: Investigation of fundamental aspects driving surfactant self-assembling and of the capability of including guest molecules or ions in their micellar aggregates is an exciting research field for theoretical and technological reasons. In this light, assembling and chelating properties of sodium bis(2-ethylhexyl)sulfosuccinate (AOTNa) towards divalent metal ion chlorides have been investigated in the gas phase by electrospray ionization mass spectrometry in negative ion mode, tandem mass spectrometry and energy-resolved mass spectrometry. METHODS:Water/methanol solutions of AOTNa and chloride salts of nickel, magnesium, calcium and manganese, with different AOTNa/metal salt ratios, …
Gas Phase Charged Aggregates of Bis(2-ethylhexyl)sulfo-succinate (AOT) and Divalent Metal Ions. First evidence of AOT solvated aggregates
2011
Assembling and chelating properties of sodium bis(2-ethylhexyl)sulfosuccinate (AOTNa) towards divalent metal ions have been investigated in the gas phase by electrospray ionization mass spectrometry. A variety of positively charged monometallated and mixed metal aggregates are formed. Interestingly, several ions contain solvent (MeOH, H2O) molecules and constitute the most abundant AOT cationic aggregates not containing sodium. These species are the first example of solvated AOT-metal ion aggregates in the gas phase. By increasing the surfactant aggregation number, the abundance of solvated species becomes lower than that of unsolvated ones. Decompositions of ionic species have been studied…
Review: Mass spectrometry of surfactant aggregates
2011
In contrast with the enormous amount of literature produced during many decades in the field of surfactant aggregation in liquid, liquid crystalline and solid phases, only a few investigations concerning surfactant self-assembling in the gas phase as charged aggregates have been carried out until now. This lack of interest is disappointing in view of the remarkable theoretical and practical importance of the inherent knowledge. The absence of surfactant–solvent interactions makes it easier to study the role of surfactant–surfactant forces in determining their peculiar self-assembling features as well as the ability of these assemblies to incorporate selected solubilizate molecules. Thus, th…