Showing papers by "University of Palermo published in 2008"

Severe Plastic Deformation (SPD) Processes for Metals

Abstract: Processes of severe plastic deformation (SPD) are defined as metal forming processes in which a very large plastic strain is imposed on a bulk process in order to make an ultra-fine grained metal The objective of the SPD processes for creating ultra-fine grained metal is to produce lightweight parts by using high strength metal for the safety and reliability of micro-parts and for environmental harmony In this keynote paper, the fabrication process of equal channel angular pressing (ECAP), accumulative roll-bonding (ARB), high pressure torsion (HPT), and others are introduced, and the properties of metals processed by the SPD processes are shown Moreover, the combined processes developed recently are also explained Finally, the applications of the ultra-fine grained (UFG) metals are discussed

Marine reserves: size and age do matter

Abstract: Marine reserves are widely used throughout the world to prevent overfishing and conserve biodiversity, but uncertainties remain about their optimal design. The effects of marine reserves are heterogeneous. Despite theoretical findings, empirical studies have previously found no effect of size on the effectiveness of marine reserves in protecting commercial fish stocks. Using 58 datasets from 19 European marine reserves, we show that reserve size and age do matter: Increasing the size of the no-take zone increases the density of commercial fishes within the reserve compared with outside; whereas the size of the buffer zone has the opposite effect. Moreover, positive effects of marine reserve on commercial fish species and species richness are linked to the time elapsed since the establishment of the protection scheme. The reserve size-dependency of the response to protection has strong implications for the spatial management of coastal areas because marine reserves are used for spatial zoning.

HER2 regulates the mammary stem/progenitor cell population driving tumorigenesis and invasion.

Abstract: The cancer stem cell hypothesis proposes that cancers arise in stem/progenitor cells through disregulation of self-renewal pathways generating tumors, which are driven by a component of 'tumor-initiating cells' retaining stem cell properties. The HER2 gene is amplified in 20-30% of human breast cancers and has been implicated in mammary tumorigenesis as well as in mediating aggressive tumor growth and metastasis. We demonstrate that HER2 overexpression drives mammary carcinogenesis, tumor growth and invasion through its effects on normal and malignant mammary stem cells. HER2 overexpression in normal mammary epithelial cells (NMEC) increases the proportion of stem/progenitor cells as demonstrated by in vitro mammosphere assays and the expression of stem cell marker aldehyde dehydrogenase (ALDH) as well as by generation of hyperplastic lesions in humanized fat pads of NOD (nucleotide-binding oligomerization domain)/SCID (severe combined immunodeficient) mice. Overexpression of HER2 in a series of breast carcinoma cell lines increases the ALDH-expressing 'cancer stem cell' population which displays increased expression of stem cell regulatory genes, increased invasion in vitro and increased tumorigenesis in NOD/SCID mice. The effects of HER2 overexpression on breast cancer stem cells are blocked by trastuzumab in sensitive, but not resistant, cell lines, an effect mediated by the PI3-kinase/Akt pathway. These studies provide support for the cancer stem cell hypothesis by suggesting that the effects of HER2 amplification on carcinogenesis, tumorigenesis and invasion may be due to its effects on normal and malignant mammary stem/progenitor cells. Furthermore, the clinical efficacy of trastuzumab may relate to its ability to target the cancer stem cell population in HER2-amplified tumors.

Nanostructured rutile TiO2 for selective photocatalytic oxidation of aromatic alcohols to aldehydes in water.

Abstract: Selective photocatalytic oxidation of aromatic alcohols to aldehydes was performed in water in the presence of TiO2 rutile photocatalysts that exhibited a low degree of crystallinity. The nanostructured rutile samples, prepared ex TiCl4 at very low temperature, ensured a selectivity toward the aldehyde 3 to 4-fold higher than the commercial rutile tested (Sigma-Aldrich).

Supported proline and proline-derivatives as recyclable organocatalysts

Abstract: In the last eight years, L-proline and L-proline derivatives, such as substituted prolinamides or pyrrolidines, have been successfully used as organocatalysts in several reactions. In this critical review we summarize the immobilization procedures of such organocatalysts highlighting their application, recoverability and reusability (86 references).

Reproducing Kernel Hilbert Spaces Regression Methods for Genomic Assisted Prediction of Quantitative Traits

Abstract: Reproducing kernel Hilbert spaces regression procedures for prediction of total genetic value for quantitative traits, which make use of phenotypic and genomic data simultaneously, are discussed from a theoretical perspective. It is argued that a nonparametric treatment may be needed for capturing the multiple and complex interactions potentially arising in whole-genome models, i.e., those based on thousands of single-nucleotide polymorphism (SNP) markers. After a review of reproducing kernel Hilbert spaces regression, it is shown that the statistical specification admits a standard mixed-effects linear model representation, with smoothing parameters treated as variance components. Models for capturing different forms of interaction, e.g., chromosome-specific, are presented. Implementations can be carried out using software for likelihood-based or Bayesian inference.

Cancer Stem Cell Analysis and Clinical Outcome in Patients with Glioblastoma Multiforme

Abstract: Purpose: Cancer stem cells (CSC) are thought to represent the population of tumorigenic cells responsible for tumor development. The stem cell antigen CD133 identifies such a tumorigenic population in a subset of glioblastoma patients. We conducted a prospective study to explore the prognostic potential of CSC analysis in glioblastoma patients. Experimental Design: We investigated the relationship between the in vitro growth potential of glioblastoma CSCs and patient death or disease progression in tumors of 44 consecutive glioblastoma patients treated with complete or partial tumorectomy followed by radiotherapy combined with temozolomide treatment. Moreover, we evaluated by immunohistochemistry and immunofluorescence the prognostic value of the relative presence of CD133 + and CD133 + /Ki67 + cells in patient tumors. Results: In vitro CSC generation and the presence of ≥2% CD133 + cells in tumor lesions negatively correlated with overall ( P = 0.0001 and 0.02, respectively) and progression-free ( P = 0.0002 and 0.01, respectively) survival of patients. A very poor overall ( P = 0.007) and progression-free ( P = 0.001) survival was observed among patients whose tumors contained CD133 + cells expressing Ki67. Taking into account symptom duration, surgery type, age, O 6 -methylguanine-DNA methyltransferase promoter methylation, and p53 status, generation of CSCs and CD133/Ki67 coexpression emerged as highly significant independent prognostic factors, with an adjusted hazard ratio of 2.92 (95% confidence interval, 1.37-6.2; P = 0.005) and 4.48 (95% confidence interval, 1.68-11.9; P = 0.003), respectively. Conclusions: The analysis of CSCs may predict the survival of glioblastoma patients. In vitro CSC generation and presence of CD133 + /Ki67 + cells are two considerable prognostic factors of disease progression and poor clinical outcome.

Cancer stem cells – old concepts, new insights

Abstract: Cancer has long been viewed as an exclusively genetic disorder. The model of carcinogenesis, postulated by Nowell and Vogelstein, describes the formation of a tumor by the sequential accumulation of mutations in oncogenes and tumor suppressor genes. In this model, tumors are thought to consist of a heterogeneous population of cells that continue to acquire new mutations, resulting in a highly dynamic process, with clones that out compete others due to increased proliferative or survival capacity. However, novel insights in cancer stem cell research suggest another layer of complexity in the process of malignant transformation and preservation. It has been reported that only a small fraction of the cancer cells in a malignancy have the capacity to propagate the tumor upon transplantation into immuno-compromised mice. Those cells are termed 'cancer stem cells' (CSC) and can be selected based on the expression of cell surface markers associated with immature cell types. In this review, we will critically discuss these novel insights in CSC-related research. Where possible we integrate these results within the genetic model of cancer and illustrate that the CSC model can be considered an extension of the classic genetic model rather than a contradictory theory. Finally, we discuss some of the most controversial issues in this field.

Synthesis and biological properties of benzothiazole, benzoxazole, and chromen-4-one analogues of the potent antitumor agent 2-(3,4-dimethoxyphenyl)-5-fluorobenzothiazole (PMX 610, NSC 721648).

Abstract: New fluorinated 2-aryl-benzothiazoles, -benzoxazoles, and -chromen-4-ones have been synthesized and their activity against MCF-7 and MDA 468 breast cancer cell lines compared with the potent antitumor benzothiazole 5. Analogues such as 9a,b and 12a,d yielded submicromolar GI50 values in both cell lines; however, none of the new compounds approached 5 in terms of antitumor potency. For 5, binding to the aryl hydrocarbon receptor appeared to be necessary but not sufficient for growth inhibition.

Inflammatory Cytokines in Acute Ischemic Stroke

Abstract: Three major cytokines, namely, tumor necrosis factor (TNF-α), interleukin (IL)-1, and IL-6 are produced by cultured brain cells after various stimuli such as ischemia. Neurones, astrocytes, microglia and oligodendrocytes can produce inflammatory mediators, and cytokine receptors are expressed constitutionally throughout the Central Nervous System (CNS), albeit at low levels. Cytokines are involved in virtually every facet of stroke and they have numerous proinflammatory and pro-coagulant effects on endothelium. TNF-α expression after stroke stimulates expression of tissue factor and adhesion molecules for leukocytes, release of interleukin-1 (IL-1), nitric oxide, factor VIII/von Willebrand factor, platelet-activating factor and endothelin, suppression of the thrombomodulin-protein C-protein S system, reduction of tissue-plasminogen activator and release of plasminogen activator inhibitor-1. Research into the actions of IL-1β in the brain initially focused on its role in host defence responses to systemic disease. IL-1β can also elicit an array of responses which could either inhibit, exacerbate or induce neuronal damage and death. IL-6 can be induced by a variety of molecules including IL-1, TNF-α, transforming growth factor-β and prostaglandins (PGs), and many other mediators such as b-amyloid, interferon-g (IFNg) and IL-4 can potentiate these primary inducers, highlighting the complex nature of IL-6 modulation. Several studies reported that plasma levels of TNF-α and IL-6 are associated with prognosis after ischemic stroke and our group showed that plasma levels of cytokines such as TNF-α, IL-1β are different in every diagnostic subtype of ischemic stroke, and how plasma levels of some immunoinflammatory markers and thrombotic-phybrinolitic markers are predictive of acute ischemic stroke diagnosis in the acute setting.

Energy performances and life cycle assessment of an Italian wind farm

Abstract: Renewable energy sources are often presented as “ clean ”. A more correct definition is that they are “cleaner” than ones based on fossil fuel conversion. When the energy consumption and the environmental impacts related to the plant's life-cycle are considered, a more comprehensive assessment of these technologies can be carried out. This paper aims to evaluate the energy and the environmental performances of the electricity production of a wind farm. The impacts related to all the phases of the wind farm construction and operation have been compared to the environmental benefits due to the “green” electricity generation during its useful life. In other terms, the goal is to trace the ecoprofile of the production of 1 kWh of electricity. A life cycle assessment (LCA) has been performed based on data related to an Italian wind farm: production and deliver of energy and raw materials, components manufacturing, transports, installation, maintenance, disassembly and disposal have been analysed. The attention focused to those life cycle steps generally neglected or not adequately investigated as installation, civil works and maintenance. The results can be assumed as representative of the Italian context and they can represent a further incentive to the diffusion of wind farms. In fact, the environmental performances of the wind farm have been compared to other power energy generation systems. The results showed a great environmental convenience of the inquired technology.

Entanglement dynamics of two independent qubits in environments with and without memory

Abstract: Here is analyzed the dynamics of two-qubit entanglement, when the two qubits are initially in a mixed extended Werner-like state and each of them is in a zero temperature non-Markovian environment. The dependence of entanglement dynamics on the purity and degree of entanglement of the initial states and on the amount of non-Markovianity is also given. This extends the previous work about non-Markovian effects on the two-qubit entanglement dynamics for initial Bell-like states [Bellomo et al., Phys. Rev. Lett. 99, 160502 (2007)]. The effect on the two-qubit entanglement dynamics of nonzero temperature in Markovian environments is finally studied.

Tracking the structural dynamics of proteins in solution using time-resolved wide-angle X-ray scattering.

Abstract: We demonstrate tracking of protein structural changes with time-resolved wide-angle X-ray scattering (TR-WAXS) with nanosecond time resolution. We investigated the tertiary and quaternary conformational changes of human hemoglobin under nearly physiological conditions triggered by laser-induced ligand photolysis. We also report data on optically induced tertiary relaxations of myoglobin and refolding of cytochrome c to illustrate the wide applicability of the technique. By providing insights into the structural dynamics of proteins functioning in their natural environment, TR-WAXS complements and extends results obtained with time-resolved optical spectroscopy and X-ray crystallography.

Normal-sodium diet compared with low-sodium diet in compensated congestive heart failure: is sodium an old enemy or a new friend?

Abstract: The aim of the present study was to evaluate the effects of a normal-sodium (120 mmol sodium) diet compared with a low-sodium diet (80 mmol sodium) on readmissions for CHF (congestive heart failure) during 180 days of follow-up in compensated patients with CHF. A total of 232 compensated CHF patients (88 female and 144 male; New York Heart Association class II-IV; 55-83 years of age, ejection fraction <35% and serum creatinine <2 mg/dl) were randomized into two groups: group 1 contained 118 patients (45 females and 73 males) receiving a normal-sodium diet plus oral furosemide [250-500 mg, b.i.d. (twice a day)]; and group 2 contained 114 patients (43 females and 71 males) receiving a low-sodium diet plus oral furosemide (250-500 mg, b.i.d.). The treatment was given at 30 days after discharge and for 180 days, in association with a fluid intake of 1000 ml per day. Signs of CHF, body weight, blood pressure, heart rate, laboratory parameters, ECG, echocardiogram, levels of BNP (brain natriuretic peptide) and aldosterone levels, and PRA (plasma renin activity) were examined at baseline (30 days after discharge) and after 180 days. The normal-sodium group had a significant reduction (P<0.05) in readmissions. BNP values were lower in the normal-sodium group compared with the low sodium group (685+/-255 compared with 425+/-125 pg/ml respectively; P<0.0001). Significant (P<0.0001) increases in aldosterone and PRA were observed in the low-sodium group during follow-up, whereas the normal-sodium group had a small significant reduction (P=0.039) in aldosterone levels and no significant difference in PRA. After 180 days of follow-up, aldosterone levels and PRA were significantly (P<0.0001) higher in the low-sodium group. The normal-sodium group had a lower incidence of rehospitalization during follow-up and a significant decrease in plasma BNP and aldosterone levels, and PRA. The results of the present study show that a normal-sodium diet improves outcome, and sodium depletion has detrimental renal and neurohormonal effects with worse clinical outcome in compensated CHF patients. Further studies are required to determine if this is due to a high dose of diuretic or the low-sodium diet.

Hsp60 expression, new locations, functions, and perspectives for cancer diagnosis and therapy

Abstract: Hsp60 in eukaryotes is considered typically a mitochondrial chaperone (also called Cpn60) but in the last few years it has become clear that it also occurs in the cytosol, the cell surface, the extracellular space, and in the peripheral blood. Studies with prokaryotic models have shown that Hsp60 plays a role in assisting nascent polypeptides to reach a native conformation, and that it interacts with Hsp10 (which also resides in the mitochondria and is also named Cpn10). In addition to its role in polypeptide folding in association with Hsp10, other functions and interacting molecules have been identified for Hsp60 in the last several years. Some of these newly identified functions are associated with carcinogenesis, specifically with tumor cell survival and proliferation. Thus, assessing the levels of Hsp60 in tumor cells and in sera of cancer patients is becoming an attractive area of investigation aiming at the development of means for practical applications in clinical oncology. Since Hsp60 participat...

Lévy flight superdiffusion: an introduction

Abstract: After a short excursion from the discovery of Brownian motion to the Richardson "law of four thirds" in turbulent diffusion, the article introduces the Levy flight superdiffusion as a self-similar Levy process. The condition of self-similarity converts the infinitely divisible characteristic function of the Levy process into a stable characteristic function of the Levy motion. The Levy motion generalizes the Brownian motion on the base of the α-stable distributions theory and fractional order derivatives. Further development on this idea lies on the generalization of the Langevin equation with a non-Gaussian white noise source and the use of functional approach. This leads to the Kolmogorov's equation for arbitrary Markovian processes. As a particular case we obtain the fractional Fokker–Planck equation for Levy flights. Some results concerning stationary probability distributions of Levy motion in symmetric smooth monostable potentials, and a general expression to calculate the nonlinear relaxation time in barrier crossing problems are derived. Finally, we discuss the results on the same characteristics and barrier crossing problems with Levy flights, recently obtained by different approaches.

High concordance of KRAS status between primary colorectal tumors and related metastatic sites: implications for clinical practice.

Abstract: Purpose Several studies have suggested that KRAS somatic mutations may predict resistance to cetuximab- and panitumumab-based treatments in metastatic colorectal cancer (CRC) patients. Nevertheless, most experiences were conducted on samples from primaries. The aim of this study was to evaluate the grade of concordance in terms of KRAS status between primaries and related metastases. Patients and methods We analyzed KRAS codon 12 and 13 mutations from formalin-fixed sections of 107 CRC primaries and related metastases. Eight pairs were excluded from the analysis because of the low amount of tumor tissue in the available samples. The main characteristics were: 50 men, 49 women; median age at diagnosis, 71 years (range, 41-84). The metastatic sites analyzed were the liver in 80 patients (80.8%), lung in seven patients (7.1%), and other sites in 12 patients (12.1%). Results A KRAS mutation was found in 38 (38.4%) primary tumors and in 36 (36.4%) related metastases. The rate of concordance was 96.0% (95% confidence interval, 90.0%-98.9%). Discordance was observed in only four (4%) patients. Conclusions Our results indicate that the detection of KRAS mutations in either primary or metastatic tumors from patients with CRC is concordant and this assessment could be used to predict response to targeted therapies such as cetuximab and panitumumab.

Total oxidation of propene at low temperature over Co3O4-CeO2 mixed oxides: Role of surface oxygen vacancies and bulk oxygen mobility in the catalytic activity

Abstract: Co 3 O 4 , CeO 2 and Co 3 O 4 –CeO 2 mixed oxides with Co/Ce nominal atomic ratio 0.1:5, prepared by co-precipitation method with sodium carbonate, were tested in the oxidation of propene under lean condition and the catalyst stability was checked by performing three consecutive heating–cooling cycles. Characterization of the textural properties were performed by surface area measurement BET, X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements. Among the Co 3 O 4 –CeO 2 mixed oxides, Co 3 O 4 (30 wt%)–CeO 2 (70 wt%) gives the best activity attaining full propene conversion at 250 °C. This sample is characterized by the presence of Co 3 O 4 particles well dispersed and in good contact with ceria according to BET and XRD data and as evidenced by SEM micrographs. Oxygen temperature-programmed desorption (O 2 -TPD) and C 3 H 6 -temperature-programmed reduction (C 3 H 6 -TPR) experiments were carried out in order to study the surface and bulk oxygen mobility and to correlate it to the activity. At temperature around 200 °C, O 2 -TPD experiments showed the desorption of mobile surface oxygen species for the most active samples, Co 3 O 4 and Co 3 O 4 (30 wt%)–CeO 2 (70 wt%). C 3 H 6 -TPR experiments for both of the oxides also evidenced a high reactivity at low temperature, especially, for Co 3 O 4 (30 wt%)–CeO 2 (70 wt%) giving at 345 °C an intense peak of CO 2 formation. Conversely, the ceria sample showed by C 3 H 6 -TPR much less pronounced oxygen bulk mobility, starting to react with propene above 500 °C and forming only CO. In this case, the catalytic activity of ceria was explained in terms of formation of surface oxygen vacancies which are relevant to the propene oxidation in presence of gaseous oxygen.

Splenic marginal zone lymphoma proposals for a revision of diagnostic, staging and therapeutic criteria

Abstract: Since the initial description of splenic marginal zone lymphoma (SMZL) in 1992, an increasing number of publications have dealt with multiple aspects of SMZL diagnosis, molecular pathogenesis and treatment. This process has identified multiple inconsistencies in the diagnostic criteria and lack of clear guidelines for the staging and treatment. The authors of this review have held several meetings and exchanged series of cases with the objective of agreeing on the main diagnostic, staging and therapeutic guidelines for patients with this condition. Specific working groups were created for diagnostic criteria, immunophenotype, staging and treatment. As results of this work, guidelines are proposed for diagnosis, differential diagnosis, staging, prognostic factors, treatment and response criteria. The guidelines proposed here are intended to contribute to the standardization of the diagnosis and treatment of these patients, and should facilitate the future development of clinical trials that could define more precisely predictive markers for histological progression or lack of response, and evaluate new drugs or treatments.

Best proximity points for cyclic Meir–Keeler contractions

Abstract: We introduce a notion of cyclic Meir–Keeler contractions and prove a theorem which assures the existence and uniqueness of a best proximity point for cyclic Meir–Keeler contractions. This theorem is a generalization of a recent result due to Eldred and Veeramani.