60 research outputs found
The role of the vastus lateralis flap in head and neck reconstruction
The Vastus lateralis flap is a very versatile flap, easy to harvest and with a long pedicle. It can be harvested as a muscle, musculo-cutaneous or chimeric flap. It is particularly suit-able for head and neck reconstruction, as it allows for a two-team approach and can be tailored to the complex three-dimensional structure of this district. In this paper, we discuss our experience and a review of the literature on the use of the free Vastus lateralis flap in the head and neck region, analyzing its indications, advan-tages and limitations. We also provide technical tips to minimize donor site morbidity
Multiscale microkinetic modelling of carbon monoxide and methane oxidation over Pt/γ-Al2O3 catalyst
Although compared to conventional diesel and gasoline engines gas engines running on methane-based fuels emit less pollutants, slip of unburnt methane is a hurdle to be overcome. In this regard, particularly noble metal-based catalysts allow for an efficient methane conversion even at low temperatures. Since these catalysts can undergo modifications under the highly dynamic operation [1] affecting activity and stability, the present work aims at creating a multiscale microkinetic model that has a strong link to the structure of the active sites, which change according to the chemical environment they are exposed. A detailed surface reaction mechanism for platinum-catalysed abatement of exhaust gases by Koop et al. [2] was used as a basis for the further development. The model is validated using light-off experiments with a monolithic Pt/Al2O3 catalyst in stoichiometric model gas mixtures. Simulations were carried out using the DETCHEMCHANNEL software [3] and show a remarkable difference, especially regarding the predicted ignition temperature. This different behaviour could be associated to the activation energies of the key reactive steps that need further investigation, i.e. dissociative adsorption of CH4. Along with theoretical considerations, spatially resolved information from experiments are used to improve the model.
[1] P. Lott, O. Deutschmann, “Lean-Burn Natural Gas Engines: Challenges and Concepts for an Efficient Exhaust Gas Aftertreatment System” Emiss. Control Sci. Technol. 7, 1-6 (2021).
[2] J. Koop, O. Deutschmann, “Detailed surface reaction mechanism for Pt-catalyzed abatement of automotive exhaust gases”, Appl. Cat. B 91, 1 (2009)
[3] O. Deutschmann, S. Tischer, C. Correa, D. Chatterjee, S. Kleditzsch, V.M. Janardhanan, N. Mladenov, H. D. Minh, H. Karadeniz, M. Hettel, V. Menon, A. Banerjee, H. Goßler, E. Daymo, DETCHEM Software package, 2.8 ed., www.detchem.com, Karlsruhe 2020
Italian Lycium barbarum L. Berry: Chemical Characterization and Nutraceutical Value:
Lycium barbarum L. has received considerable attention in recent years also in western countries because of the interesting healthy value of these berries. In this paper, goji samples cultivated in Southern Italy were analyzed for their chemical composition and nutritional profile in order to characterize fruits of Italian origin and to increase the awareness about their nutraceutical value. Lipid fraction was characterized by high percentages of unsaturated fatty acids, in particular oleic and linoleic acids, and very low values of atherogenic and thrombogenic indexes (0.1 and 0.2, respectively). In addition, goji berry was an interesting source of phytosterols (41.5 mg/100 g), essentially represented by β-sitosterol. Carotenoid analysis showed the presence of zeaxanthin, in esterified form, with high content of zeaxanthin dipalmitate (277.9 mg/100 g). Finally, in vitro antioxidant capacity and phenolic compounds were investigated. The results suggested that goji hydro-alcoholic extract possessed the ability to scavenge free radicals. Phenolic acids were clearly the most abundant compounds followed by flavonols and favanols. The results reported in this study confirm that Italian L. barbarum berry is a rich source of bioactive molecules with nutraceutical properties
Age-related central regulation of orexin and NPY in the short-lived African killifish Nothobranchius furzeri
Orexin A (OXA) and neuropeptide Y (NPY) are two hypothalamic neuropeptides involved in the regulation of feeding behavior and food intake in all vertebrates. Accumulating evidences document that they undergo age-related modifications, with consequences on metabolism, sleep/wake disorders and progression of neurodegenerations. The present study addressed the age related changes in expression and distribution of orexin A (its precursor is also known as hypocretin\u2014HCRT) and NPY, and their regulation by food intake in the short-lived vertebrate model Nothobranchius furzeri. Our experiments, conducted on male specimens, show that: (a) HCRT and OXA and NPY mRNA and protein are localized in neurons of diencephalon and optic tectum, as well as in numerous fibers projecting through the entire neuroaxis, and are colocalized in specific nuclei; (b) in course of aging, HCRT and NPY expressing neurons are localized also in telencephalon and rhombencephalon; (c) HCRT expressing neurons increased slightly in the diencephalic area of old animals and in fasted animals, whereas NPY increased sharply; (d) central HCRT levels are not regulated neither in course of aging nor by food intake; and (e) central NPY levels are augmented in course of aging, and regulated by food intake only in young. These findings represent a great novelty in the study of central orexinergic and NPY-ergic systems in vertebrates', demonstrating an uncommon and unprecedented described regulation of these two orexigenic neuropeptides
Il contributo di La Volpe alla teoria dinamica dell'economia
The paper presents the dynamic theory proposed by La Volpe in 1936. This analysis has been innovative in many ways: general equilibrium is defined as temporary, the presence and the role of expectations are introduced, the intertemporal choice of the agents is determined in such a way as to anticipate the life-cycle theory, and some important problems that emerge in the dynamic analysis are addressed. The relevance of La Volpe's book led Michio Morishima to publish its English translation
Measurement of the Ge 70 (n,γ) cross section up to 300 keV at the CERN n-TOF facility
©2019 American Physical Society.Neutron capture data on intermediate mass nuclei are of key importance to nucleosynthesis in the weak component of the slow neutron capture processes, which occurs in massive stars. The (n,γ) cross section on Ge70, which is mainly produced in the s process, was measured at the neutron time-of-flight facility n-TOF at CERN. Resonance capture kernels were determined up to 40 keV neutron energy and average cross sections up to 300 keV. Stellar cross sections were calculated from kT=5 keV to kT=100 keV and are in very good agreement with a previous measurement by Walter and Beer (1985) and recent evaluations. Average cross sections are in agreement with Walter and Beer (1985) over most of the neutron energy range covered, while they are systematically smaller for neutron energies above 150 keV. We have calculated isotopic abundances produced in s-process environments in a 25 solar mass star for two initial metallicities (below solar and close to solar). While the low metallicity model reproduces best the solar system germanium isotopic abundances, the close to solar model shows a good global match to solar system abundances in the range of mass numbers A=60-80.Peer reviewedFinal Published versio
TRAP1 regulates stemness through Wnt/β-catenin pathway in human colorectal carcinoma
Colorectal carcinoma (CRC) is a common cause of cancer-related death worldwide. Indeed, treatment failures are triggered by cancer stem cells (CSCs) that give rise to tumor repopulation upon initial remission. Thus, the role of the heat shock protein TRAP1 in stemness was investigated in CRC cell lines and human specimens, based on its involvement in colorectal carcinogenesis, through regulation of apoptosis, protein homeostasis and bioenergetics. Strikingly, co-expression between TRAP1 and stem cell markers was observed in stem cells located at the bottom of intestinal crypts and in CSCs sorted from CRC cell lines. Noteworthy, TRAP1 knockdown reduced the expression of stem cell markers and impaired colony formation, being the CSC phenotype and the anchorage-independent growth conserved in TRAP1-rich cancer cells. Consistently, the gene expression profiling of HCT116 cells showed that TRAP1 silencing results in the loss of the stem-like signature with acquisition of a more-differentiated phenotype and the downregulation of genes encoding for activating ligands and target proteins of Wnt/β-catenin pathway. Mechanistically, TRAP1 maintenance of stemness is mediated by the regulation of Wnt/β-catenin signaling, through the modulation of the expression of frizzled receptor ligands and the control of β-catenin ubiquitination/phosphorylation. Remarkably, TRAP1 is associated with higher expression of β-catenin and several Wnt/β-catenin target genes in human CRCs, thus supporting the relevance of TRAP1 regulation of β-catenin in human pathology. This study is the first demonstration that TRAP1 regulates stemness and Wnt/β-catenin pathway in CRC and provides novel landmarks in cancer biology and therapeutics
Efficacy of a new technique - INtubate-RECruit-SURfactant-Extubate - "IN-REC-SUR-E" - in preterm neonates with respiratory distress syndrome: Study protocol for a randomized controlled trial
Background: Although beneficial in clinical practice, the INtubate-SURfactant-Extubate (IN-SUR-E) method is not successful in all preterm neonates with respiratory distress syndrome, with a reported failure rate ranging from 19 to 69 %. One of the possible mechanisms responsible for the unsuccessful IN-SUR-E method, requiring subsequent re-intubation and mechanical ventilation, is the inability of the preterm lung to achieve and maintain an "optimal" functional residual capacity. The importance of lung recruitment before surfactant administration has been demonstrated in animal studies showing that recruitment leads to a more homogeneous surfactant distribution within the lungs. Therefore, the aim of this study is to compare the application of a recruitment maneuver using the high-frequency oscillatory ventilation (HFOV) modality just before the surfactant administration followed by rapid extubation (INtubate-RECruit-SURfactant-Extubate: IN-REC-SUR-E) with IN-SUR-E alone in spontaneously breathing preterm infants requiring nasal continuous positive airway pressure (nCPAP) as initial respiratory support and reaching pre-defined CPAP failure criteria. Methods/design: In this study, 206 spontaneously breathing infants born at 24+0-27+6 weeks' gestation and failing nCPAP during the first 24 h of life, will be randomized to receive an HFOV recruitment maneuver (IN-REC-SUR-E) or no recruitment maneuver (IN-SUR-E) just prior to surfactant administration followed by prompt extubation. The primary outcome is the need for mechanical ventilation within the first 3 days of life. Infants in both groups will be considered to have reached the primary outcome when they are not extubated within 30 min after surfactant administration or when they meet the nCPAP failure criteria after extubation. Discussion: From all available data no definitive evidence exists about a positive effect of recruitment before surfactant instillation, but a rationale exists for testing the following hypothesis: a lung recruitment maneuver performed with a step-by-step Continuous Distending Pressure increase during High-Frequency Oscillatory Ventilation (and not with a sustained inflation) could have a positive effects in terms of improved surfactant distribution and consequent its major efficacy in preterm newborns with respiratory distress syndrome. This represents our challenge. Trial registration: ClinicalTrials.gov identifier: NCT02482766. Registered on 1 June 2015
Aboveground biomass density models for NASA's Global Ecosystem Dynamics Investigation (GEDI) lidar mission
NASA's Global Ecosystem Dynamics Investigation (GEDI) is collecting spaceborne full waveform lidar data with a primary science goal of producing accurate estimates of forest aboveground biomass density (AGBD). This paper presents the development of the models used to create GEDI's footprint-level (similar to 25 m) AGBD (GEDI04_A) product, including a description of the datasets used and the procedure for final model selection. The data used to fit our models are from a compilation of globally distributed spatially and temporally coincident field and airborne lidar datasets, whereby we simulated GEDI-like waveforms from airborne lidar to build a calibration database. We used this database to expand the geographic extent of past waveform lidar studies, and divided the globe into four broad strata by Plant Functional Type (PFT) and six geographic regions. GEDI's waveform-to-biomass models take the form of parametric Ordinary Least Squares (OLS) models with simulated Relative Height (RH) metrics as predictor variables. From an exhaustive set of candidate models, we selected the best input predictor variables, and data transformations for each geographic stratum in the GEDI domain to produce a set of comprehensive predictive footprint-level models. We found that model selection frequently favored combinations of RH metrics at the 98th, 90th, 50th, and 10th height above ground-level percentiles (RH98, RH90, RH50, and RH10, respectively), but that inclusion of lower RH metrics (e.g. RH10) did not markedly improve model performance. Second, forced inclusion of RH98 in all models was important and did not degrade model performance, and the best performing models were parsimonious, typically having only 1-3 predictors. Third, stratification by geographic domain (PFT, geographic region) improved model performance in comparison to global models without stratification. Fourth, for the vast majority of strata, the best performing models were fit using square root transformation of field AGBD and/or height metrics. There was considerable variability in model performance across geographic strata, and areas with sparse training data and/or high AGBD values had the poorest performance. These models are used to produce global predictions of AGBD, but will be improved in the future as more and better training data become available
VENOUS THROMBOSIS IN FREE FLAPS: A STUDY OF THE PHENOMENOLOGY, HISTORY AND CLINICAL SIGNS IN AN EXPERIMENTAL MODEL OF RATS.
The introduction of free flaps with microsurgical vascular anastomosis has made reconstructions,
that would have been considered impossible forty years ago, possible. The
limitations of this technique are mainly due to necrosis of the transplanted tissue caused
by blockage of the vessels of the flap’s vascular pedicle due to the formation of thrombi
at the level of the surgical anastomosis. Thrombosis is handled by removing the thrombus
in the shortest possible time, thus allowing restoration of the blood flow. Currently
clinical observation is the best way to evaluate the survival of a flap but, being subjective,
it is dependent on the observer’s experience. The purpose of this study is to identify the
first sure sign of venous thrombosis in a murine model of complete venous occlusion of
the pedicle of an inguinal flap, postoperatively and after the restoration of blood flow following
a period of stasis; so as to simulate the monitoring of re-thrombosis after recanalization
of a thrombosed anastomosis
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