Exergy analysis of a cooling system: experimental investigation on the consequences of the retrofit of R22 with R422D

In this article, the performances of a walk-in air cooler working with R22 and its substitute R422D are experimentally studied. To define a full comparison on the performance characteristics of R22 and R422D, both an energetic and an exergetic analyses are proposed. The experimental investigation was carried out considering four levels of refrigeration capacity: 920, 1340, 1925 and 2250 W. All tests were run at steady-state conditions and by keeping the value of the external air temperature equal to 22°C. The experimental analysis allowed the determination of the COP, the exergetic efficiency, the exergy flow destroyed in each component and other variables characterizing the working of the plant. The results demonstrated that COP of R422D is, on average, 20% lower than that of R22. Furthermore, for plant whose condenser is air cooled, R422D could lead to increase the fan speed or to adopt bigger blowers

Latent Space Autoregression for Novelty Detection

Novelty detection is commonly referred to as the discrimination of observations that do not conform to a learned model of regularity. Despite its importance in different application settings, designing a novelty detector is utterly complex due to the unpredictable nature of novelties and its inaccessibility during the training procedure, factors which expose the unsupervised nature of the problem. In our proposal, we design a general framework where we equip a deep autoencoder with a parametric density estimator that learns the probability distribution underlying its latent representations through an autoregressive procedure. We show that a maximum likelihood objective, optimized in conjunction with the reconstruction of normal samples, effectively acts as a regularizer for the task at hand, by minimizing the differential entropy of the distribution spanned by latent vectors. In addition to providing a very general formulation, extensive experiments of our model on publicly available datasets deliver on-par or superior performances if compared to state-of-the-art methods in one-class and video anomaly detection settings. Differently from prior works, our proposal does not make any assumption about the nature of the novelties, making our work readily applicable to diverse contexts

Endoscopic findings and psychometric abnormalities: what is the relationship in upper endoscopic outpatients?

Background. Psychological disorders are often associated with diseases of the upper digestive tract. Although emotions can influence gastrointestinal function in healthy individuals, psychological setting in upper gastrointestinal patients are unclear. We evaluate the psychological alterations prevalence in outpatients submitted to upper endoscopy. Materials and Methods. A total of 130 patients (50 males and 80 females; mean age 54±17 years) submitted to upper gastrointestinal endoscopy, were enrolled over the period May 2009 - September 2010. Subjects were asked to complete questionnaires before endoscopic examination. Alexithymia, anxiety, depression and coping style were assessed using the Toronto Alexithymia Scale, Spielberger Trait Anxiety Inventory, Beck Depression Inventory and Coping Inventory for Stressful Situations, respectively. Results. Coping impairment, Alexithymia, Anxiety and Depression were found respectively in 80.3%, 25.4%, 24.6% and 17.2%, often in association. Task-oriented, emotion-oriented and avoidance-oriented alterations were found in 41.8%, 40% and 30.6%, respectively. No correlations were demonstrated between diagnosis of upper gastrointestinal disease and psychometric results. Conclusions. In our study, a high prevalence of psychometric alterations in gastrointestinal outpatients was unconnected with endoscopic findings, especially considering coping style alterations. This aspect should be taken into account in patients management and a long-term follow-up should clarify a possible role of these factors in patients prognosis and compliance

Endoscopic Submucosal Dissection of Gastric Neoplastic Lesions. An Italian, Multicenter Study

Endoscopic submucosal dissection (ESD) allows removing neoplastic lesions on gastric mucosa, including early gastric cancer (EGC) and dysplasia. Data on ESD from Western countries are still scanty. We report results of ESD procedures performed in Italy. Data of consecutive patients who underwent ESD for gastric neoplastic removal were analyzed. The en bloc resection rate and the R0 resection rates for all neoplastic lesions were calculated, as well as the curative rate (i.e., no need for surgical treatment) for EGC. The incidence of complications, the one‐month mortality, and the recurrence rate at one‐year follow‐up were computed. A total of 296 patients with 299 gastric lesions (80 EGC) were treated. The en bloc resection was successful for 292 (97.6%) and the R0 was achieved in 266 (89%) out of all lesions. In the EGC group, the ESD was eventually curative in 72.5% (58/80) following procedure. A complication occurred in 30 (10.1%) patients. Endoscopic treatment was successful in all 3 perforations, whereas it failed in 2 out of 27 bleeding patients who were treated with radiological embolization (1 case) or surgery (1 case). No procedure‐related deaths at one‐month follow‐up were observed. Lesion recurrence occurred in 16 (6.2%) patients (6 EGC and 10 dysplasia). In conclusion, the rate of both en bloc and R0 gastric lesions removal was very high in Italy. However, the curative rate for EGC needs to be improved. Complications were acceptably low and amenable at endoscopy

Evaluating growth and intrinsic water-use efficiency in hardwood and conifer mixed plantations

Abstract Key message Juglans, Fraxinus, Quercus and Pinus species seem to better maximize the carbon–water ratio providing useful indications on species selection for forestry plantations in areas with increasing drought risk. Abstract Maximizing carbon sequestration for a given water budget is extremely important in the contest of climate change in the Mediterranean region, which is characterized by increasing temperatures and rising water stress. This issue is fundamental for plantation stands, where limited water availability during the growing season reduces CO2 assimilation and, consequently, tree growth. In this study, the main objective was to investigate the performances in terms of carbon–water balance of conifer (Pinus halepensis and Cupressus sempervirens) and hardwood (Quercus robur, Juglans regia, Fraxinus excelsior and Populus spp.) mixed plantations. To this aim, we used carbon isotope signatures to evaluate the intrinsic water-use efficiency (iWUE) and the species-specific relationship between basal area increments (BAI) and iWUE. At the species level, the highest iWUE values corresponded to the lowest carbon accumulation in terms of BAI, for water-saving species such as Cupressus. Conversely, Populus had the lowest iWUE and the highest BAI accumulation. Juglans, Fraxinus, and Pinus showed the most balanced ratio between BAI and iWUE. Overall, no clear correlation of iWUE and BAI was evident within all species, except for Populus and Cupressus. Considering projected aridification and increased temperatures that will negatively impact the growth, our data suggest that Pinus, for conifers, and Quercus, Juglans, Fraxinus for hardwood species should be preferred when choosing species for forestry plantation, as they performed better in terms of BAI and iWUE ratio

A comparison of melatonin and α-lipoic acid in the induction of antioxidant defences in L6 rat skeletal muscle cells.

Aging is characterized by a progressive deterioration in physiological functions and metabolic processes. The loss of cells during aging in vital tissues and organs is related to several factors including oxidative stress and inflammation. Skeletal muscle degeneration is common in elderly people; in fact, this tissue is particularly vulnerable to oxidative stress since it requires large amounts of oxygen, and thus, oxidative damage is abundant and accumulates with increasing age. Melatonin (N-acetyl-5-methoxytryptamine) is a highly efficient scavenger of reactive oxygen species and it also exhibits beneficial anti-inflammatory and anti-aging effects. This study investigated the susceptibility of rat L6 skeletal muscle cells to an induced oxidative stress following their exposure to hydrogen peroxide (50 μM) and evaluating the potential protective effects of pre-treatment with melatonin (10 nM) compared to the known beneficial effect of alpha-lipoic acid (300 μM). Hydrogen peroxide-induced obvious oxidative stress; it increased the expression of tumour necrosis factor-alpha and in turn promoted nuclear factor kappa-B and overrode the endogenous defence mechanisms. Conversely, pre-treatment of the hydrogen peroxide-exposed cells to melatonin or alpha-lipoic acid increased endogenous antioxidant enzymes, including superoxide dismutase-2 and heme oxygenase-1; moreover, they ameliorated significantly oxidative stress damage and partially reduced alterations in the muscle cells, which are typical of aging. In conclusion, melatonin was equally effective as alpha-lipoic acid; it exhibited marked antioxidant and anti-aging effects at the level of skeletal muscle in vitro even when it was given in a much lower dose than alpha-lipoic acid

Holistic health: Predicting our data future (from inter-operability among systems to co-operability among people)

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