A refrigerant system (like that of a supermarket) is a complex system if we consider all the stakeholders throughout its lifecycle phases (use, maintenance, technological update, end of life). The lack of stakeholders' interaction during the design and other lifecycle stages of such a system generates issues and leads to sub-optimal system performances. We used the RID methodology to identify the main areas for improvement for these activities related to the refrigerant system. It is precisely designed to analyze, within the scope of activity, the major stakeholders' problems (user profiles) during lifecycle phases (use situations) to deduce areas for improvement (value buckets). Therefore, we built a process of interviews and data collection on existing practices to feed into a RID model. The first results are an archetypal description of the actors and problems encountered according to the lifecycle phases. The second part is a prioritized mapping of the areas to improve despite a certain number of known available solutions but proven insufficient.

This paper presents a review of the various aeronautical air conditioning systems that are currently available and discusses possible system configurations in the context of the aeronautical environmental control systems. Descriptions of the standard vapor compression cycle and air cycles are provided. The latter includes, simple-cycle, bootstrap-cycle, simple-bootstrap cycle (3-wheel) and condensing cycle (4-wheel). Water separation and air recirculation systems are also explored. A comparison between vapor compression cycles and air cycles is provided, as well as a comparison between different air cycles. Air cycle units are far less efficient than vapor compression cycle units, but they are lighter and more reliable for an equivalent cooling capacity. Details regarding the aircraft conceptual design phase along with general criteria for the selection of an air conditioning system are provided. Additionally, industry trends and technological advances are examined. Conclusions are compiled to guide the systems engineer in the search for the most appropriate design for a particular application.

Use of cooled and frozen semen is becoming increasingly prevalent in the equine industry. However, these procedures cause harmful effects in the sperm cell resulting in reduced cell lifespan and fertility rates. Apoptosis and necrosis-related events are increased during semen cryopreservation. However, a third type of cell death, named autophagy, has not been studied during equine semen storage. Light chain (LC)3 protein is a key component of the autophagy pathway. Under autophagy activation, LC3-I is lipidated and converted to LC3-II. The ratio of LC3-II/LC3-I is widely used as a marker of autophagy activation. The main objective of this study was to investigate whether LC3 is processed during cooling, freezing and the stressful conditions associated with these technologies. A secondary objective was to determine if LC3 processing can be modulated and if that may improve the quality of cryopreserved semen. LC3 processing was studied by Western blot with a specific antibody that recognized both LC3-I and LC3-II. Viability was assessed by flow cytometry. Modulation of LC3-I to LC3-II was studied with known autophagy activators (STF-62247 and rapamycin) or inhibitors (chloroquine and 3-MA) used in somatic cells. The results showed that conversion of LC3-I to LC3-II increased significantly during cooling at 4°C, freezing/thawing and each of the stressful conditions tested (UV radiation, oxidative stress, osmotic stress and changes in temperature). STF-62247 and rapamycin increased the LC3-II/LC3-I ratio and decreased the viability of equine sperm, whereas chloroquine and 3-MA inhibited LC3 processing and maintained the percentage of viable cells after 2 h of incubation at 37°C. Finally, refrigeration at 4°C for 96 h and freezing at −196°C in the presence of chloroquine and 3-MA resulted in higher percentages of viable cells. In conclusion, results showed that an ‘autophagy-like’ mechanism may be involved in the regulation of sperm viability during equine semen cryopreservation. Modulation of autophagy during these reproductive technologies may result in an improvement of semen quality and therefore in higher fertility rates.

Many articles have summarized the changing epidemiology of Clostridium difficile infections (CDI) in humans, but the emerging presence of C. difficile in foods and animals and possible measures to reduce human exposure to this important pathogen have been infrequently addressed. CDIs have traditionally been assumed to be restricted to health-care settings. However, recent molecular studies indicate that this is no longer the case; animals and foods might be involved in the changing epidemiology of CDIs in humans; and genome sequencing is disproving person-to-person transmission in hospitals. Although zoonotic and foodborne transmission have not been confirmed, it is evident that susceptible people can be inadvertently exposed to C. difficile from foods, animals, or their environment. Strains of epidemic clones present in humans are common in companion and food animals, raw meats, poultry products, vegetables, and ready-to-eat foods, including salads. In order to develop science-based prevention strategies, it is critical to understand how C. difficile reaches foods and humans. This review contextualizes the current understanding of CDIs in humans, animals, and foods. Based on available information, we propose a list of educational measures that could reduce the exposure of susceptible people to C. difficile. Enhanced educational efforts and behavior change targeting medical and non-medical personnel are needed.

Introduction. Films act as semi-permeable gaseous barriers capable of maintaining fruit postharvest quality; thus coatings consisting of non-traditional sources may represent an alternative tool for producers. The objective of our work was to investigate the effect of a galactomannan coating on postharvest quality and physiology of ‘Tommy Atkins’ mangoes. Materials and methods. Physiologically mature mangoes were divided into four lots and stored for 16 d. Control uncoated fruits (lot 1) were stored at ambient temperature (25 °C), the second lot was uncoated and refrigerated (14 °C), the third lot was coated and stored at ambient temperature, and the fourth lot was coated and refrigerated. Fruit were analyzed for physicochemical quality parameters, antioxidant enzymatic activity and lipid peroxidation. Results and discussion. Control fruit (lot 1) lost almost twice the weight of uncoated refrigerated (lot 2) and coated mangoes at both temperatures (lots 3 and 4); the fruit of lot 1 softened faster. Regarding the antioxidant enzymes, the activity of superoxide dismutase decreased throughout storage without statistical differences between treatments and catalasic activity was significantly inhibited under refrigeration. At ambient temperature, coating delayed the catalasic activity peak to day 12, which was coincident with the lowest lipid peroxidation degree, evidencing the association of free radical production and scavenging mechanisms. The galactomannan coating was efficient in reducing weight loss and delaying softening; thus, it maintained quality of ‘Tommy Atkins’ mangoes for a longer period of time than the control treatment during storage at ambient temperature. Refrigeration (14 °C) enhanced the performance of the galactomannan coating; it was effective in slowing down the metabolism and delaying softening to day 12.

Cette étude présente une machine frigorifique fonctionnant suivant un cycle à compression-absorption. Le système proposé utilise le couple ammoniac-eau comme fluide frigorigène et opère à trois niveaux de pression. L’absorbeur fonctionne à une pression intermédiaire Pint, prise entre la pression de l’évaporateur (PEV) et celle du condenseur (PCD). Les principaux éléments du système proposé sont modélisés. Les résultats de la simulation numérique sont comparés à ceux relatifs au système conventionnel. L’étude comparative met en évidence les avantages du système objet de cette étude. Elle prouve le double avantage de la pression intermédiaire non seulement dans l’amélioration des performances de la machine à absorption mais aussi dans la réduction de la température du fonctionnement du générateur. Nous avons montré que pour des températures d’évaporation et de condensation prises respectivement à –10 °C et 40 °C, le cycle frigorifique fonctionne à une température du générateur TGE = 75 °C avec un COP de l’ordre de 0,56. La présente étude révèle que pour les mêmes conditions de fonctionnement, la machine frigorifique simple étage, présente un COP qui ne dépasse pas 0,51 avec une température du générateur de l’ordre de 135 °C. Le système hybride présente ainsi le privilège de fonctionner à basse température et de présenter des performances relativement améliorées.

Introduction. Figs of the variety ‘Roxo de Valinhos’ are currently cooled in a cold room at a temperature between (1 and 3) °C, and it is unknown how long it takes to cool the fruits to that temperature. The work was based on the need to determine the parameters of forced-air precooling of figs packed in a carton box used for exportation and commercialization in São Paulo State, Brazil. Materials and methods. The fruits were harvested at the harvest rami stage (3/4 of maturity) and at size “type 8”, corresponding to eight fruits per box, making up a total of 24 fruits per package. Forty-eight packages were utilized, 24 on each side to form a Californian tunnel. The airflow was 2.8 L·s–1 per kg of product, with an average velocity of the air of 2.0 m·s–1. The initial interior temperature of the fruits was 20 °C and the final temperature was 1 °C. The evolution of the fig interior temperature was registered. Results. The cooling curve was drawn and the exponential analytical model to predict the precooling parameters was made based on the experimental data. The cooling curve of fig showed a typical behavior; the average fruit temperature during precooling presented a rapid fall at the beginning of the cooling, and slowly declined when it was close to the final temperature. Conclusion. The cooling time was 110 min, the cooling coefficient was 0.0344 min–1, the Biot number was 1.3 and the convective heat transference coefficient was 23.8 °C·W–1·m–2.

Kefir is an acidic, mildly alcoholic dairy beverage produced by the fermentation of milk with a grain-like starter culture (Koroleva, 1988). These grains usually contain a relatively stable and specific balance of microbes that exist in a complex symbiotic relationship (Obermann & Libudzisz, 1998; Witthuhn et al. 2004). The different groups of microbes present in the grains are active at different stages of the fermentation (Koroleva, 1982). The lactococci, including Lactococcus lactis subsp. lactis, Lc. lactis subsp. cremoris and Lc. lactis subsp. diacetilactis provide rapid acid development during the first hours of the fermentation (Litopoulou-Tzanetaki & Tzanetakis, 2000). As the acidity of the milk increases it provides favourable conditions for the growth of the lactobacilli (Rea et al. 1996). The yeasts, acetic acid bacteria and the aroma-producing microbes, mainly leuconostocs, have a much slower growth rate than the lactic acid producers, resulting in the slow production of the aroma compounds and the gradual increase in the concentration of these substances in the later stages of the fermentation (Koroleva, 1982).