Experimental accelerated shelf life determination of a ready-to-eat processed food

The most direct way to estimate the shelf life of a product is to conduct simulation tests which are time consuming and expensive. Conversely, accelerated shelf life tests can be successfully used for stable products having long expected shelf life. The aim of the study was directed to verify the possibility to apply an accelerated shelf life test to perishable food products having a short-expected shelf life, such as a new ready-to-eat processed food preparation, composed mainly by cereals, tuna and chicken, packed in thermo-sealed trays and pasteurised. Different samples of the product were stored in thermal abuse conditions, collected periodically and subjected to determinations of TVB-N, pH and sensorial characteristics. Q10 and activation energy were calculated allowing to obtain a predictive evaluation of the product shelf life at the 4°C recommended temperature. The product shelf life was assessed at 26 days vs the 30 days expected by the manufacturer, showing the possibility to apply successfully ASLT for products having short shelf life, saving both time and money

FOOT: a new experiment to measure nuclear fragmentation at intermediate energies

Summary: Charged particle therapy exploits proton or 12C beams to treat deep-seated solid tumors. Due to the advantageous characteristics of charged particles energy deposition in matter, the maximum of the dose is released to the tumor at the end of the beam range, in the Bragg peak region. However, the beam nuclear interactions with the patient tissues induces fragmentation both of projectile and target nuclei and needs to be carefully taken into account. In proton treatments, target fragmentation produces low energy, short range fragments along all the beam range, which deposit a non negligible dose in the entry channel. In 12C treatments the main concern is represented by long range fragments due to beam fragmentation that release their dose in the healthy tissues beyond the tumor. The FOOT experiment (FragmentatiOn Of Target) of INFN is designed to study these processes, in order to improve the nuclear fragmentation description in next generation Treatment Planning Systems and the treatment plans quality. Target (16O and 12C nuclei) fragmentation induced by –proton beams at therapeutic energies will be studied via an inverse kinematic approach, where 16O and 12C therapeutic beams impinge on graphite and hydrocarbon targets to provide the nuclear fragmentation cross section on hydrogen. Projectile fragmentation of 16O and 12C beams will be explored as well. The FOOT detector includes a magnetic spectrometer for the fragments momentum measurement, a plastic scintillator for ΔE and time of flight measurements and a crystal calorimeter to measure the fragments kinetic energy. These measurements will be combined in order to make an accurate fragment charge and isotopic identification. Keywords: Hadrontherapy, Nuclear fragmentation cross sections, Tracking detectors, Scintillating detector

Necessary and sufficient conditions for the stability of microwave amplifiers with variable termination impedances

New criteria to check conditional stability of microwave amplifiers with input and output terminations varying in pre-specified circular regions surrounding complex nominal values are proposed. Necessary and sufficient conditions are provided both in terms of the immittance parameters Lambdaij (i.e., zij , yij , gij or hij) and in terms of the scattering parameters sij. Proposed conditions can be easily implemented in any commercial computer-aided design tool and are suitable to be used as design goals within an optimization routine: this allows to optimize the tradeoff between stability constraints under termination variations and performance in a yield-oriented design flow. A case study, in which a distributed amplifier has been designed, shows the advantages of the proposed approach

A low-voltage class-AB OTA exploiting adaptive biasing

We present a low voltage approach to design an adaptive bias circuit for a class-AB input stage, and exploit it to design a fully-differential 0.6 V class-AB symmetrical OTA that also features cascode dynamic biasing and a class-AB CMFB circuit. Simulations in 0.13 μm CMOS technology show a 42x increase of the bias current when signal is applied, that yields a faster settling time with respect to a class-A OTA designed with the same static current. The OTA provides 43.6 dB gain and good large-signal FOM when compared with sub-1 V OTAs in the literature, and is still operational at 0.4 V supply voltage

Statistical nonlinear model of MESFET and HEMT devices

Accurate statistical models of FET devices are needed for yield-oriented MMIC design. In particular, currently used linear statistical models are not adequate in applications where bias point variations have a strong impact on overall yield. The paper describes a nonlinear statistical model of MESFET and HEMT devices in which statistical parameters are considered as Gaussian multivariate random variables. An automatic procedure is developed to achieve extraction of the statistical model of a FET device from a database of DC Ids and S-parameter measurements, and it is checked on a GaAs HEMT monolithic process. A statistical model has been extracted for Philips PML-D02AH GaAs HEMT devices and accurate evaluation of the S-parameters covariance matrix has been made. Statistical pair-wise tests on mean values, standard deviations and correlation coefficients show that the proposed methodology has the capability of reproducing statistical population distributions

Indicators of protein spoilage in fresh and defrosted crustaceans and cephalopods stored in domestic condition

In relation to consumer demand, crustaceans and cephalopods are sold as both fresh and defrosted. It is well known that total volatile basic nitrogen (TVB-N) and volatile amine values, especially, biogenic amines and biogenic amine index, are expression of freshness of fish products, but there is a lack of knowledge of their acceptability limits, for crustaceans and cephalopods. In order to assess these limits, real-time shelf life tests were carried out, relating the results of TVB-N, biogenic amines and BAI to the sensory evaluation of crustaceans and cuttlefishes, both fresh and defrosted. TVB-N and biogenic amines have been analysed in many shrimp species and cuttlefishes purchased in Perugia (Central Italy), and BAI was calculated as the ratio between different biogenic amines. The results show levels of TVB-N and spermine different between shrimp and cuttlefish (TVB-N: 37 vs. 14 mg/100 g; spermine: 4 vs. 14 mg/kg, respectively) while the other biogenic amines and BAI are close to zero in both. Among biogenic amines, cadaverine and even more putrescine significantly affect BAI values and seem to be the most effective in assessing limits of acceptability during storage

Combined effect of salinity and hypoxia in seedlings of two varieties of Panicum coloratum: Morphology, root system architecture, oxidative damage and antioxidant response

The effect of the combination of salinity and waterlogging may be additive, or alternatively, more or less detrimental than effects of them separately. Our objective was to evaluate the effects of waterlogging, salinity and the combination of both on seedlings of Panicum coloratum, a subtropical forage grass. Seedlings of cultivars Kapivera INTA (KA) and Klein (KL) were exposed to treatments in a controlled hydroponic experiment and several morphological and physiological variables evaluated. The effect of hypoxia was almost null when the plants were already in salinity. KA showed lower reduction than KL in shoot biomass. Both varieties showed synergistic effect of stresses, indicating that biomass production was less affected under the combined treatment than predicted from them separately. Root length, tips, forks and volume were reduced by saline exposure, while no differences in root architecture was noticeable between cultivars. Plants of KA increased leaf temperature in salinity. Nonenzymatic oxidative response and the activity of antioxidant enzymes increased in saline conditions and were lower in KA than in KL. Oxidative damage was equivalent between cultivars and among stress conditions. Proline content was comparable to control in hypoxia but increased significantly in saline conditions, with a higher response in KL than in KA. Increases in Na+ (over 900%) and decreases in K+ (50%) tissue concentration in salinity occurred only in KA. In general, P. coloratum proved more tolerant to hypoxia than to salinity or their combination, KA being more tolerant than KL. Findings provide basis to deepen research into tolerance mechanisms.Fil: Lifschitz, Mauro Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación de la Cadena Láctea. - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea; ArgentinaFil: Tommasino, Exequiel Arturo. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Zabala, Juan Marcelo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Ciencias Agropecuarias del Litoral. - Universidad Nacional del Litoral. Instituto de Ciencias Agropecuarias del Litoral.; ArgentinaFil: Grunberg, Karina Alejandra. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Estudios Agropecuarios - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Estudios Agropecuarios; ArgentinaFil: Ramos, Julio Cesar. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Ciencias Agropecuarias del Litoral. - Universidad Nacional del Litoral. Instituto de Ciencias Agropecuarias del Litoral.; ArgentinaFil: Tomas, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación de la Cadena Láctea. - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea; Argentin

Evaluation of the shelf life and cooking methods of Ascoli-style olives, an Italian specialty food

In recent years, consumers have been increasingly interested in the quality and safety of specialty food products that are perceived as healthy and wholesome. However, few studies have been carried out to assess the effects of domestic cooking on the fate of pathogens in meat-based products. The present study aimed to assess the shelf life of ready-to-cook Ascoli-style olives, an Italian specialty food preparation, through accelerated shelf life tests. A challenge test was also carried out to test the efficacy of cooking methods on the survival of Salmonella Senftemberg strains. Accelerated shelf life assays, including physico-chemical assays (investigating the total volatile basic nitrogen and pH), microbiological counts (Enterobacteriaceae counts) and sensory parameters (appearance, color, odor, flavor and texture) allowed us to obtain sound information on the durability of pre-cooked Ascoli-style olives in an affordable and efficient manner. This is therefore an effective method that could be exploited by food business operators hoping to provide scientific information on product shelf life assessments. The challenge tests demonstrated that fan-baking in an electric oven at 200 °C for 12 min. and deep frying for 4 min. are the more effective treatments needed to inactivate the artificially inoculated Salmonella Senftemberg strains