627 research outputs found
Mitochondria in the line of fire
In this issue of Cell Death & Differentiation, two papers (a review and a research article) discuss and investigate the importance of targeting mitochondria to arrest cancer cell proliferation and overcome cell death resistance. The review by Sainero-Alcolado et al. summarizes the main metabolic derangements originating from specific mitochondrial defects and presents the mitochondrial enzymes that can be targeted by potential antineoplastic compounds [1]; Quarato et al. explored the mechanistic link between mitochondrial physiology, intracellular Ca2+ unbalance, and cell death
Analytical and experimental FWHM of a gamma camera: theoretical and practical issues
It is well known that resolution on a gamma camera varies as a
function of distance, scatter and the camera\u2019s characteristics (collimator type,
crystal thickness, intrinsic resolution etc). Manufacturers frequently provide only
a few pre-calculated resolution values (using a line source in air, 10\u201315 cm from
the collimator surface and without scattering). However, these are typically not
obtained in situations resembling a clinical setting. From a diagnostic point of view,
it is useful to know the expected resolution of a gamma camera at a given distance
from the collimator surface for a particular setting in order to decide whether it is
worth scanning patients with \u201csmall lesion\u201d or not. When dealing with absolute
quantification it is also mandatory to know precisely the expected resolution and its
uncertainty in order to make appropriate corrections.
Aim. Our aims are: to test a novel mathematical approach, the cubic spline interpolation,
for the extraction of the full width at half maximum (FWHM) from the
acquisition of a line source (experimental resolution) also considering measurement
uncertainty; to compare it with the usually adopted methods such as the gaussian
approach; to compare it with the theoretical resolution (analytical resolution) of a
gamma camera at different distances; to create a web-based educational program
with which to test these theories.
Methods. Three mathematical methods (direct calculation, global interpolation using
gaussian and local interpolation using splines) for calculatingFWHMfroma line
source (planar scintigraphy) were tested and compared. A NEMA Triple Line Source
Phantom was used to obtain static images both in air and with different scattering
levels. An advanced, open-source software (MATLAB/Octave and PHP based) was
created \u201cad hoc\u201d to obtain and compareFWHMvalues and relative uncertainty.
Results and Conclusion. Local interpolation using splines proved faster and more
reliable than the usually-adopted Gaussian interpolation. The proposed freely available
software proved effective in assessing bothFWHMand its uncertainty
Assessing the mechanical stability of trees in artificial plantations of Pinus nigra J. F. Arnold using the LWN tool under different site indexes
In young black pine plantations, the most valuable and interesting thinning scheme is mainly based on the positive selection of dominant and well-shaped trees to be candidates for carbon sequestration, timber production and natural regeneration. The mechanical stability of candidate trees is here a fundamental skill that must be taken into account and the slenderness ratio (HD) is one of the main indicators. HD has been recently proved to be correlated to the living whorl number (LWN) by Cantiani & Chiavetta (2015). In this study, the statistical model was re-calibrated in order to study the influence of soil fertility on the HD - Living whorls number (LWN) relationship.The fertility-balanced models estimated a different LWN threshold. The model for the highest fertility class (Site index 24) estimated 12 LWN (RMSE of 20%). Similarly, a lower value were detected for the other two fertility classes, SI20 and SI16, where 10 LWN were considered enough with an associated RMSE of 16% and 17% respectively. Compared to the general model provided by Cantiani & Chiavetta (11 LWN with 18% of RMSE) the site index approach improved the accuracy and reliability
Interpretazioni dell’affresco della torre abbaziale di San Zeno a Verona
RIASSUNTO: Von Sacken (1865), Gerola (1927) e Zuliani (1992) ritengono che l’affresco della Torre di San Zeno a Verona rappresenti l’omaggio di diversi popoli a Federico II, l’autore vede invece nella scena l’incontro di Salomone con la Regina di Saba: tale iconografia è comunque suscettibile diessere interpretata in senso filoimperiale.PAROLE-CHIAVE: Federico II – Salomone – Regina di SabaABSTRACT: Von Sacken (1865), Gerola (1927) and Zuliani (1992) are convinced that the fresco of the Tower of St Zeno’s cathedral in Verona represents the tribute of different peoples to the emperor Frederick II. On thecontrary, the author thinks that the fresco depicts the meeting between Solomon and the Queen of Sheba: this representation can still be interpreted in a pro-imperial way.KEYWORDS: Frederick II – Solomon – Queen of Sheb
The mitochondrial permeability transition pore is a dispensable element for mitochondrial calcium efflux
AbstractThe mitochondrial permeability transition pore (mPTP) has long been known to have a role in mitochondrial calcium (Ca2+) homeostasis under pathological conditions as a mediator of the mitochondrial permeability transition and the activation of the consequent cell death mechanism. However, its role in the context of mitochondrial Ca2+ homeostasis is not yet clear. Several studies that were based on PPIF inhibition or knock out suggested that mPTP is involved in the Ca2+ efflux mechanism, while other observations have revealed the opposite result.The c subunit of the mitochondrial F1/FO ATP synthase has been recently found to be a fundamental component of the mPTP. In this work, we focused on the contribution of the mPTP in the Ca2+ efflux mechanism by modulating the expression of the c subunit. We observed that forcing mPTP opening or closing did not impair mitochondrial Ca2+ efflux. Therefore, our results strongly suggest that the mPTP does not participate in mitochondrial Ca2+ homeostasis in a physiological context in HeLa cells
Vibration Monitoring in the Compressed Domain with Energy-Efficient Sensor Networks
Structural Health Monitoring (SHM) is crucial for the development of safe infrastructures. Onboard vibration diagnostics implemented by means of smart embedded sensors is a suitable approach to achieve accurate prediction supported by low-cost systems. Networks of sensors can be installed in isolated infrastructures allowing periodic monitoring even in the absence of stable power sources and connections. To fulfill this goal, the present paper proposes an effective solution based on intelligent extreme edge nodes that can sense and compress vibration data onboard, and extract from it a reduced set of statistical descriptors that serve as input features for a machine learning classifier, hosted by a central aggregating unit. Accordingly, only a small batch of meaningful scalars needs to be outsourced in place of long time series, hence paving the way to a considerable decrement in terms of transmission time and energy expenditure. The proposed approach has been validated using a real-world SHM dataset for the task of damage identification from vibration signals. Results demonstrate that the proposed sensing scheme combining data compression and feature estimation at the sensor level can attain classification scores always above 94%, with a sensor life cycle extension up to 350x and 1510x if compared with compression-only and processing-free implementations, respectively
Dothistroma needle blight in natural forests of Corsican pine in La Sila Massif, Calabria, Italy
Genetic correlations between measures of beef quality traits and their predictions by near-infrared spectroscopy in the Piemontese cattle breed.
The aims of this study were to predict beef quality traits (BQ: colour, shear force, drip and cooking losses) of Piemontese cattle using near-infrared spectroscopy (NIRS) and to estimate genetic parameters for measured BQ and their predictions by NIRS. Heritabilities and genetic correlations for measured BQ and their predictions based on NIRS were estimated through bivariate Bayesian analyses. Heritability estimates for measured BQ were of intermediate magnitude (from 0.10 to 0.63) and similar to those for NIRS predictions. The genetic correlations between BQ measures and their predictions by NIRS were very high for colour traits, high for drip loss, and nil for shear force and cooking loss. NIRS predictions can be proposed as indicator traits in breeding programs for enhancement of colour traits and drip loss
Stand structure and influence of climate on growth trends of a marginal forest population of Pinus nigra spp. nigra
The Black pine of Villetta Barrea (Pinus nigra ssp. nigra var italica) is a variety of the nigra subspecies. It is naturally distributed only in the Abruzzo Region, near the village of Villetta Barrea, with a rear-edge marginal population. Â A dendrochronological sampling of the population was implemented with the aim of studying its stand structure and the most probable interactions between growth trends and climate. Mensurational data were used to characterize the stand and, furthermore, the general correlation function (CF) and the moving correlation function (MCF), with a 30 years window, were used to assess the interrelation between the growth of the tree rings and the climate.The results indicated that the past forest management, mainly carried out with thinnings from below and selective cuttings, influenced the current structure of the forest (mean diameter) but no differences in growth trends were detected within the population.The survey on Villetta Barrea Black pine showed a positive and statistically significant correlation between the ring-width and the average temperatures of the months of December (before the ring formation - t-1), February and March; but it also showed a negative correlation with the temperatures of July, September and October of the current year (t).Moreover, the analysis with moving correlation functions suggested that, in the last decades, the population has negatively reacted to very few climate factors and, in particular, to the changes in temperatures (both minimum and maximum temperatures). This is especially true for the shifts occurred in September, the year of the ring formation.</p
Predictive ability of mid-infrared spectroscopy for major mineral composition and coagulation traits of bovine milk by using the uninformative variable selection algorithm
Milk minerals and coagulation properties are important for both consumers and processors, and they can aid in increasing milk added value. However, large-scale monitoring of these traits is hampered by expensive and time-consuming reference analyses. The objective of the present study was to develop prediction models for major mineral contents (Ca, K, Mg, Na, and P) and milk coagulation properties (MCP: rennet coagulation time, curd-firming time, and curd firmness) using mid-infrared spectroscopy. Individual milk samples (n = 923) of Holstein-Friesian, Brown Swiss, Alpine Grey, and Simmental cows were collected from single-breed herds between January and December 2014. Reference analysis for the determination of both mineral contents and MCP was undertaken with standardized methods. For each milk sample, the mid-infrared spectrum in the range from 900 to 5,000 cm 121 was stored. Prediction models were calibrated using partial least squares regression coupled with a wavenumber selection technique called uninformative variable elimination, to improve model accuracy, and validated both internally and externally. The average reduction of wavenumbers used in partial least squares regression was 80%, which was accompanied by an average increment of 20% of the explained variance in external validation. The proportion of explained variance in external validation was about 70% for P, K, Ca, and Mg, and it was lower (40%) for Na. Milk coagulation properties prediction models explained between 54% (rennet coagulation time) and 56% (curd-firming time) of the total variance in external validation. The ratio of standard deviation of each trait to the respective root mean square error of prediction, which is an indicator of the predictive ability of an equation, suggested that the developed models might be effective for screening and collection of milk minerals and coagulation properties at the population level. Although prediction equations were not accurate enough to be proposed for analytic purposes, mid-infrared spectroscopy predictions could be evaluated as phenotypic information to genetically improve milk minerals and MCP on a large scale
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