University of Palermo

About: University of Palermo is a education organization based out in Palermo, Italy. It is known for research contribution in the topics: Population & Medicine. The organization has 15621 authors who have published 40250 publications receiving 964384 citations. The organization is also known as: Università degli Studi di Palermo & Universita degli Studi di Palermo.

Chemical mapping of a fumarolic field: La Fossa Crater, Vulcano Island (Aeolian Islands, Italy)

Abstract: [1] The performance of a newly-developed portable gas analyzer, capable of real-time measurement of CO2, SO2 and H2S concentrations in volcanic gases, was tested at La Fossa Crater, Vulcano Island. The gas analyzer was used to acquire about 3000 determinations over the fumarolic field, allowing the definition of its chemical structure and heterogeneity. Our high-resolution analysis reveals that, in December 2004, the La Fossa fumarolic field was characterized by an oxidized inner core (SO2/H2S ratios of ∼3), and by more reducing conditions on its northern edge (SO2/H2S ratios of ∼1; range: 0.2–3.3). CO2/(SO2+H2S) molar ratios averaged 35 ± 21, with overlapping compositions for rim and inner crater fumaroles. S-poor compositions (CO2/(SO2+H2S) ≥ 50) characterized the field margins, probably due to deposition of native sulfur. Based on the above data and an SO2 flux of 18 ± 3 t·d−1, we estimate CO2 and H2S output rates from the volcano of 420 ± 250 and 4 ± 2 t·d−1, respectively.

The 13C urea breath test in the diagnosis of Helicobacter pylori infection

Abstract: Summary The urea breath test (UBT) is one of the most important non-invasive methods for detecting Helicobacter pylori infection The test exploits the hydrolysis of orally administered urea by the enzyme urease, which H pylori produces in large quantities Urea is hydrolysed to ammonia and carbon dioxide, which diVuses into the blood and is excreted by the lungs Isotopically labelled CO2 can be detected in breath using various methods Labelling urea with 13 C is becoming increasingly popular because this non-radioactive isotope is innocuous and can be safely used in children and women of childbearing age Breath samples can also be sent by post or courier to remote analysis centres The test is easy to perform and can be repeated as often as required in the same patient A meal must be given to increase the contact time between the tracer and the H pylori urease inside the stomach The test has been simplified to the point that two breath samples collected before and 30 minutes after the ingestion of urea in a liquid form suYce to provide reliable diagnostic information The cost of producing 13 C-urea is high, but it may be possible to reduce the dosage further by administering it in capsule form An isotope ratio mass spectrometer (IRMS) is generally used to measure 13 C enrichment in breath samples, but this machine is expensive In order to reduce this cost, new and cheaper equipment based on non-dispersive, isotope selective, infrared spectroscopy (NDIRS) and laser assisted ratio analysis (LARA) have recently been developed These are valid alternatives to IRMS although they cannot process the same large number of breath samples simultaneously These promising advances will certainly promote the wider use of the 13 C-UBT, which is especially useful for epidemiological studies in children and adults, for screening patients before endoscopy, and for assessing the efficacy of eradication regimens

Coronal Loops: Observations and Modeling of Confined Plasma

Abstract: Coronal loops are the building blocks of the X-ray bright solar corona. They owe their brightness to the dense confined plasma, and this review focuses on loops mostly as structures confining plasma. After a brief historical overview, the review is divided into two separate but not independent sections: the first illustrates the observational framework, the second reviews the theoretical knowledge. Quiescent loops and their confined plasma are considered, and therefore topics such as loop oscillations and flaring loops (except for non-solar ones which provide information on stellar loops) are not specifically addressed here. The observational section discusses loop classification and populations, and then describes the morphology of coronal loops, its relationship with the magnetic field, and the concept of loops as multi-stranded structures. The following part of this section is devoted to the characteristics of the loop plasma, and of its thermal structure in particular, according to the classification into hot, warm and cool loops. Then, temporal analyses of loops and the observations of plasma dynamics and flows are illustrated. In the modeling section starts some basics of loop physics are provided, supplying some fundamental scaling laws and timescales, a useful tool for consultation. The concept of loop modeling is introduced, and models are distinguished between those treating loops as monolithic and static, and those resolving loops into thin and dynamic strands. Then more specific discussions address modeling the loop fine structure, and the plasma flowing along the loops. Special attention is devoted to the question of loop heating, with separate discussion of wave (AC) and impulsive (DC) heating. Finally, a brief discussion about stellar X-ray emitting structures related to coronal loops is included and followed by conclusions and open questions.

Friction stir welding of lap joints: Influence of process parameters on the metallurgical and mechanical properties

Abstract: Aluminum alloys are widely used in the aircraft industries even if such materials present lower ductility with respect to steels, anisotropy phenomena and, more important, they are often “difficult” to be welded or even “non-weldable”. In the last years the friction stir welding process (FSW) was proposed and applied in order to get good mechanical and technological performances of the joints. In this paper, an experimental and numerical investigation on the lap joining of AA2198-T4 aluminum alloy blanks by FSW is presented. In particular the joints strength and metallurgical properties are investigated by varying the joint configuration and the tool geometry and rotational speed. It is found that the use of cylindrical–conical pin tools and the correct choice of the relative sheet positioning increase the welded nugget extension and integrity improving the mechanical performances of the obtained joints.

Effects of resveratrol, curcumin, berberine and other nutraceuticals on aging, cancer development, cancer stem cells and microRNAs

Abstract: Natural products or nutraceuticals have been shown to elicit anti-aging, anti-cancer and other health-enhancing effects. A key target of the effects of natural products may be the regulation of microRNA (miR) expression which results in cell death or prevents aging, diabetes, cardiovascular and other diseases. This review will focus on a few natural products, especially on resveratrol (RES), curcumin (CUR) and berberine (BBR). RES is obtained from the skins of grapes and other fruits and berries. RES may extend human lifespan by activating the sirtuins and SIRT1 molecules. CUR is isolated from the root of turmeric (Curcuma longa). CUR is currently used in the treatment of many disorders, especially in those involving an inflammatory process. CUR and modified derivatives have been shown to have potent anti-cancer effects, especially on cancer stem cells (CSC). BBR is also isolated from various plants (e.g., Coptis chinensis) and has been used for centuries in traditional medicine to treat diseases such as adult- onset diabetes. Understanding the benefits of these and other nutraceuticals may result in approaches to improve human health.