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result(s) for
"Losio, Paolo A."
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Refractive indices of layers and optical simulations of Cu(In,Ga)Se2 solar cells
by
Bürki, Melanie
,
Bissig, Benjamin
,
Feurer, Thomas
in
204 Optics / Optical applications
,
209 Solar cell / Photovoltaics
,
306 Thin film / Coatings
2018
Cu(In,Ga)Se
2
-based solar cells have reached efficiencies close to 23%. Further knowledge-driven improvements require accurate determination of the material properties. Here, we present refractive indices for all layers in Cu(In,Ga)Se
2
solar cells with high efficiency. The optical bandgap of Cu(In,Ga)Se
2
does not depend on the Cu content in the explored composition range, while the absorption coefficient value is primarily determined by the Cu content. An expression for the absorption spectrum is proposed, with Ga and Cu compositions as parameters. This set of parameters allows accurate device simulations to understand remaining absorption and carrier collection losses and develop strategies to improve performances.
Journal Article
Gravure printed Ag/conductive polymer electrodes and simulation of their electrical properties
by
Schneider, René
,
Losio, Paolo A.
,
Nüesch, Frank A.
in
Artificial loads
,
CAE) and Design
,
Computer architecture
2019
In this paper, some practical issues related to the manufacturing, and design criteria related to the application in devices of a hybrid silver grid/poly (3,4-ethylenedioxythiophene) semi-transparent electrode are discussed. The electrodes are fabricated by gravure printing and screen printing. Experiments showed that defects in the printed grid due to imperfect ink transfer from the gravure roll to the substrate are detrimental to electrode performance. Various parameters like gravure cell design, printing speed, or particle size of the ink were investigated to minimize the fraction of defects and to obtain highly conductive grids. It will be demonstrated that overprinting of the lines is a feasible strategy to minimize the number of defects without noticeably broadening the lines. While a defect-free grid is prerequisite for such a hybrid device, for applications even stronger design criteria hold. That is addressed in the second part of the paper, where the electrical properties of the printed grids are simulated. With two exemplary device architectures, namely an organic light-emitting diode (OLED) and an organic photovoltaic cell, artificial load layers are integrated into the device structure, and potential maps are calculated. The examples show how simulations can be deployed to design and optimize grid electrodes for a specific application.
Journal Article
Refractive indices of layers and optical simulations of Cu(In,Ga)Se 2 solar cells
2018
Cu(In,Ga)Se
based solar cells have reached efficiencies close to 23%. Further knowledge-driven improvements require accurate determination of the material properties. Here, we present refractive indices for all layers in Cu(In,Ga)Se
solar cells with high efficiency. The optical bandgap of Cu(In,Ga)Se
does not depend on the Cu content in the explored composition range, while the absorption coefficient value is primarily determined by the Cu content. An expression for the absorption spectrum is proposed, with Ga and Cu compositions as parameters. This set of parameters allows accurate device simulations to understand remaining absorption and carrier collection losses and develop strategies to improve performances.
Journal Article
Growth Rate Determination of Listeria monocytogenes in Ready-To-Eat Fish Products Under Different Storage Conditions for Possible Shelf-Life Extension
by
Merigo, Daniela
,
Norton, Alessandro
,
Ducoli, Stefania
in
Backup software
,
Contamination
,
Convenience foods
2025
An increasing trend among food business operators (FBOs) to extend the shelf life of Ready-To-Eat (RTE) fish products over 5 days, the duration usually assigned to this kind of product, has been observed recently. In this study, three independent challenge tests (food artificial contamination) were performed on tuna fillet, marinated salmon tartare, and cubed salmon, with the aim of calculating the maximum growth rate (Vmax) of Listeria monocytogenes and estimating the time required to reach the legal limit of 2 log CFU/g, as established by European Regulation 2073/2005. The pathogen counts were fitted by the model of Baranyi and Roberts to calculate the Vmax, which were 0.041, 0.020, and 0.039 log CFU/g·h−1, respectively, for the tuna fillet, marinated salmon tartare, and cubed salmon at 10 °C. These results can help FBOs in assigning the correct shelf life based on hygienic practices during the process, product characteristics, and storage conditions. The time to reach the legal limit greatly depends on the starting concentration of the pathogen and on the storage temperature. The challenges for FBOs and the health authorities include reducing the contamination of L. monocytogenes, controlling the retail temperatures, and implementing the analytical tests for quick responses.
Journal Article
Inactivation of Listeria monocytogenes and Salmonella spp. in Milano-Type Salami Made with Alternative Formulations to the Use of Synthetic Nitrates/Nitrites
2022
During the manufacture of Italian salami, a traditional meat product, a sequence of hurdles like meat fermentation, air-drying, and long ripening processes are generally sufficient to inhibit the growth of most pathogens. Furthermore, Italian salami are traditionally produced by adding synthetic nitrates/nitrites to raw meat with safety and technological aims, even if controversial opinions about their use still remain, particularly in relation to the consumer demand for natural food products. In this context, the aim of the study was to investigate the inactivation of Listeria monocytogenes and Salmonella spp. during the manufacturing process of Milano-type salami made with different formulations to evaluate the contribution of the hurdles and the vegetable or synthetic additives on the inactivation of pathogens. Thus, a challenge study was performed dividing ca. 400 kg of Milano-type salami batter into three batches: Batch (A) without nitrates/nitrites; Batch (B) with vegetable nitrates, and Batch (C) with synthetic nitrates/nitrites. The batches were separately inoculated with L. monocytogenes and Salmonella spp. and the pathogens’ survival was evaluated during the fermentation, draining, and 70-day ripening of the Milano-type salami. The pathogen counts decreased in all tested conditions, even though the highest inactivation of L. monocytogenes and Salmonella spp. (p < 0.05) was observed when nitrates or nitrites were added to the batter. This study shows how the safety of these products cannot exclude the aspect of the hurdle technology during the process, which plays a major role in the reduction of pathogens, but additives like nitrates and nitrites allow for a greater margin of safety. Thus, further studies are needed to validate the use of natural compounds as alternatives to conventional preservatives in meat products. These results may provide new information to support food business operators in producing traditional foods with alternative preservatives and competent authorities in verifying the safety of the products made with natural compounds, and to control the process parameters responsible for the synergistic effect against pathogens such as L. monocytogenes and Salmonella spp.
Journal Article
Foodborne Pathogens in In-Line Milk Filters and Associated On-Farm Risk Factors in Dairy Farms Authorized To Produce and Sell Raw Milk in Northern Italy
by
ARRIGONI, NORMA
,
RIU, RAFFAELA
,
GIACOMETTI, FEDERICA
in
Agriculture
,
Animals
,
Biological and medical sciences
2012
All dairy farms authorized to produce and sell raw milk in a province of Northern Italy were investigated to determine the presence of Campylobacter spp., verocytotoxin-producing Escherichia coli (VTEC), Listeria monocytogenes, and Salmonella spp. in in-line milk filters and to assess their association with suspected risk factors on farms. A logistic regression model was used to analyze data collected describing the characteristics and management practices of 27 farms and the microbiological status of 378 in-line milk filters by both culture-based and molecular methods. Thermotolerant Campylobacter, VTEC, and L. monocytogenes were detected in 24 (6.45%), 32 (8.4%), and 2 (0.5%) samples, respectively. No Salmonella spp. were detected. For risk analysis, data of L. monocytogenes and Salmonella spp. were not included in the model because of the low prevalence or absence of these organisms. The univariate analysis disclosed that the presence of VTEC and/or Campylobacter spp. in milk filters was associated with lack of cleanliness of bedding, water trough, and feed trough; nonevaluation of water hardness; lack of cleanliness of milk tank; and nonapplication of forestripping. After multivariate analysis, an association was observed with inadequate cleanliness of bedding and milk tank and the nonapplication of forestripping. PCR analysis of milk filters was a rapid and sensitive method for the microbiological evaluation of herd contamination status and should be included among the registration requirements for the authorization to produce and sell raw milk. Specific control actions must be incorporated into the farmer's daily practices to ensure the low-risk production of raw milk.
Journal Article
Behavior of Listeria innocua during the manufacturing and pit-ripening of Formaggio di Fossa di Sogliano PDO cheese
2020
Formaggio di Fossa di Sogliano is a traditiol Italian Protected Desigtion of Origin (PDO) cheese ripened for a minimum of 5 months, with the feature of a ripening of at least 80 to at most 100 days in pits, digged into tuffaceous rocks according to medieval tradition of Italy. In this study, a challenge test using Listeria innocua as a surrogate of Listeria monocytogenes was performed, with the aim of increasing knowledge concerning the impact of the Fossa cheese process, and especially of the traditiol ripening process of this PDO, on the behaviour of L. monocytogenes. Pasteurized milk was experimentally inoculated with 4.5 log CFU/mL cocktail by three L. innocua strains, and L. innocua and Mesophilic Lactic Acid Bacteria (LAB) counts as well as the evolution of temperatures, pH and aw values were monitored throughout the manufacturing and ripening processes. Throughout the ripening in maturation room a constant temperature of 8°C was observed reaching a temperature between 10 and 15.5°C during ripening into pit. In the fil products data for LAB concentration, pH and aw values were roughly in accordance with literature, even if some differences were, probably due to variability of artisal cheese productions. The numbers ofL. innocua showed a slight decrease but remained stable until the end of ripening in maturation room, whereas a significant reduction of the microorganism was observed in the fil product, at the end of the ripening into the pit. The findings give scientific evidence that the process of this PDO prevented theL. innocua growth, allowing us to speculate a similar behaviour of L. monocytogenes. Based on this study, the recommendation to extend as much as possible the ripening into pit (from 80 to 100 days) was provided to food business operators as a risk mitigation strategy to be implemented.
Journal Article
One-Day Molecular Detection of Salmonella and Campylobacter in Chicken Meat: A Pilot Study
2021
Salmonella and Campylobacter ssp. are bacterial pathogens responsible for most foodborne infections in EU countries. Poultry serves as a reservoir for these pathogens, and its important role in the meat industry makes it essential to develop a rapid detection assay able to provide results in one day. Indeed, the rapid identification of foodborne pathogens is an important instrument for the monitoring and prevention of epidemic outbreaks. To date, Salmonella and Campylobacter screening is mainly conducted through molecular methods (PCR or real-time PCR) performed after 18–24 h long enrichments. In this study, we evaluated short enrichments (0, 2, 4, and 6 h) combined with a colorimetric loop-mediated isothermal AMPlification (LAMP) or real-time PCR to detect Salmonella and Campylobacter in poultry meat contaminated at different concentration levels (101, 103, and 105 CFU/g). Our results show that real-time PCR allows the detection of Salmonella and Campylobacter, even after shorter enrichment times than prescribed by ISO references; particularly, it detected Salmonella down to 101 CFU/g since T0 and Campylobacter from 103 CFU/g since T0. Detection with LAMP was comparable to real-time PCR without the requirement of a thermal cycler and with shorter execution times. These characteristics make colorimetric LAMP a valid alternative when one-day results are needed, improving the timely identification of positive meat batches, even in the absence of specialized instrumentation.
Journal Article
Field handling conditions of raw milk sold in vending machines: experimental evaluation of the behaviour of Listeria monocytogenes, Escherichia coli O157:H7, Salmonella Typhimurium and Campylobacter jejuni
2012
The direct sale by farmers of raw milk for human consumption has been allowed in Italy since 2004. The aim of this study was to evaluate the behaviour of selected foodborne pathogens in raw milk sold in vending machines, in field handling conditions, and during shelf-life from production to consumption. Temperature of storage of raw milk in 33 farms authorized to produce and sell raw milk were investigated from farm to vending machine delivery, together with consumer habits in one province of the Emilia-Romagna region of northern Italy. Failure to maintain appropriate low temperatures during shelf-life was recorded and 43% of consumers did not boil milk before consumption. Listeria monocytogenes, Escherichia coli O157:H7, Salmonella Typhimurium and Campylobacter jejuni strains were inoculated into raw milk samples, and the best (4°C as established by law) and worst temperature storage conditions detected (variable temperature) were simulated. Boiling tests were performed for each pathogen considered at high and low levels of contamination. Results showed an increase in L. monocytogenes in milk stored at 4°C and at variable temperatures recorded in shelf-life monitoring, an increase in E. coli O157:H7 and S. Typhimurium at variable temperatures but not at 4°C, and a decrease in C. jejuni in all storage conditions. Boiling milk is effective in making it safe for consumers.
This study provides evidence that appropriate handling of raw milk, maintaining low temperatures, together with consumer education concerning boiling raw milk before consumption are key factors in preventing foodborne infections linked to raw milk consumption, and helps assess the risk of foodborne infection linked to raw milk consumption.
Journal Article
MRI versus Mammography plus Ultrasound in Women at Intermediate Breast Cancer Risk: Study Design and Protocol of the MRIB Multicenter, Randomized, Controlled Trial
by
Corcione, Stefano
,
Pediconi, Federica
,
Camera, Lucia
in
Biopsy
,
Breast cancer
,
contrast-enhanced magnetic resonance imaging
2021
In women at high/intermediate lifetime risk of breast cancer (BC-LTR), contrast-enhanced magnetic resonance imaging (MRI) added to mammography ± ultrasound (MX ± US) increases sensitivity but decreases specificity. Screening with MRI alone is an alternative and potentially more cost-effective strategy. Here, we describe the study protocol and the characteristics of enrolled patients for MRIB feasibility, multicenter, randomized, controlled trial, which aims to compare MRI alone versus MX+US in women at intermediate breast cancer risk (aged 40–59, with a 15–30% BC-LTR and/or extremely dense breasts). Two screening rounds per woman were planned in ten centers experienced in MRI screening, the primary endpoint being the rate of cancers detected in the 2 arms after 5 years of follow-up. From July 2013 to November 2015, 1254 women (mean age 47 years) were enrolled: 624 were assigned to MX+US and 630 to MRI. Most of them were aged below 50 (72%) and premenopausal (45%), and 52% used oral contraceptives. Among postmenopausal women, 15% had used hormone replacement therapy. Breast and/or ovarian cancer in mothers and/or sisters were reported by 37% of enrolled women, 79% had extremely dense breasts, and 41% had a 15–30% BC-LTR. The distribution of the major determinants of breast cancer risk profiles (breast density and family history of breast and ovarian cancer) of enrolled women varied across centers.
Journal Article