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Fungemia is a life-threatening condition associated with high mortality; the most frequently isolated genus is Candida. Candida glabrata is of particular concern because of its increasing resistance to azoles. We evaluated common lab tests accessible by almost all healthcare professionals to estimate the post-test probability of recovery of C. glabrata from a blood culture collected by venipuncture, positive for fungi identified by microscopic examination. Patients with blood cultures positive for C. glabrata had significantly higher median values of serum creatinine (P=0.006), and a value of ≥1.45 mg/dL was the best cut-off in discriminating C. glabrata from other Candida spp., with 0.67 [95% Confidence Interval (CI): 0.49-0.85] sensitivity and 0.75 (95% CI: 0.66-0.84) specificity; Youden's J statistic: 0.42. The receiver operator characteristic curve analysis showed an area under the curve of 0.718 (95% CI: 0.603-0.833); P=0.001. Therefore, given a pre-test probability of 24% and applying the Bayes' theorem, the post-test probability of C. glabrata fungemia with creatinine values ≥1.45 mg/dL increased to 45.8%. In conclusion, we showed how the probability of recovery of C. glabrata from blood cultures collected by venipuncture and positive for fungi can be better estimated using concurrent creatinine values.

Objectives Given the ongoing pandemic emergency, there is a need to identify SARS CoV-2 infection in various community settings. Rapid antigen testing is spreading worldwide, but diagnostic accuracy is extremely variable. Our study compared a microfluidic rapid antigen test with a reference molecular assay in patients admitted to the emergency department (ED) of a general hospital from October 2020 to January 2021. Methods Nasopharyngeal swabs collected in patients with suspected COVID-19 and in patients with no symptoms suggesting COVID-19, but requiring hospitalization, were obtained. Results 792 patients of median age 71 years were included. With a prevalence of 21%, the results showed: 68.7% (95% confidence interval [CI]: 60.9–75.5) sensitivity; 95.2% (95% CI: 93.1–96.7) specificity; 79.2% (95% CI: 71.4–85.3) positive predictive value (PPV); 91.9% (95% CI: 89.5–93.9) negative predictive value; 3.8 (95% CI: 2.7–5.3) positive likelihood ratio (LR+); and 0.09 (95% CI: 0.07–0.1) negative likelihood ratio (LR−). In the symptomatic subgroup, sensitivity increased to 81% (95% CI: 70.3–88.6) and PPV to 96.9% (95% CI: 88.5–99.5), along with an LR+ of 32 (95% CI: 8.2–125.4). Conclusions The new rapid antigen test showed an overall excellent diagnostic performance in a challenging situation, such as that of an ED during the COVID-19 emergency.

A prototype ejector chiller with nominal cooling power of 40 kW, designed according to the “CRMC” criterion, has been tested by our research group since 2011. The prototype has undergone several refinements and finally has been upgraded to R1233zd(E), which is non-flammable, has low-GWP and favourable thermodynamic properties, i.e. “dry-expansion” and moderate pressure at generator. In terms of saturation pressure curve, the new fluid is similar to R245fa, which was previously used in the prototype. Hence, R1233zd(E) has been basically used as a “drop-in” replacement. The ejector chiller was tested at different evaporation temperatures (2.5 to 10°C), typical of air conditioning applications. Saturation temperatures at generator from 95 to 105°C have been selected as representative of waste-heat recovery. The experimental findings prove that the CRMC ejector has a satisfactory performance with the new working fluid.

This paper numerically investigates the performance of a high capacity, industrial ejector chiller working with the non-flammable, low GWP refrigerant R1233zd(E). The test procedures adopted to acquire the experimental data are explained in part 1 of this work. Different turbulence models were examined in order to accurately predict the ejector off-design transition and critical pressure. A peculiar difference has been noticed between the numerical results obtained when initializing the CFD simulation from the solution of a case with lower or higher condenser pressure. This difference may partly explain the difficulties in the accurate predictions of the critical conditions reported by this and other works in the literature. A detailed discussion is presented on the nature and possible cause of this phenomenon, which is identified as typical of non-linear fluid dynamics.

Objectives: to evaluate the effectiveness of a blood culture management intervention consisting of the implementation of an incubator in a rehabilitation setting, 4 km from the Alessandria hospital and remotely connected to the central laboratory.Methodology: the Borsalino Rehabilitation Center of Alessandria is 4 km far from the Microbiology laboratory, so the estimated time between collection and incubation is often greater than the recommended 4 hours, a factor that can compromise blood culture sensitivity and response times. To improve the diagnostic process, in June 2017 an incubator connected remotely with the Microbiology laboratory was introduced in the rehabilitation center.Results: the microbiological results of two equivalent time periods were compared: 1st July 2017 – 1st July 2019, after the management intervention, 1st May 2015 – 1st May 2017, before the installation of the instrument.Conclusions: placing an incubator in a "strategic" area for the timely incubation of blood cultures makes it possible to reduce the workload and improve results in terms of timing and quality

Background: the study of vaginal microbiota is mainly performed by molecular methods. Nevertheless, they are expensive and not easily available in clinical microbiology laboratories. MALDI-TOF MS is being increasingly adopted for fast and accurate identification of pathogens from clinical samples. Aim of this study was to evaluate MALDI-TOF MS for identification of culturable bacterial species directly from plates streaked with vaginal swabs from a population of patients in childbearing age.Methods: We included women of childbearing age evaluated from October 2020 to October 2021. Identification was performed by means of Vitek® MS system.Results: A total of 381 patients were included in the study. Mean age was 33.3 years (±7.7) and 218/381 (57.2%) were pregnant. The most frequent isolates were: Lactobacillus crispatus 85/381 (22.3%), Lactobacillus acidophilus/gasseri 77/381 (20.2%) and Lactobacillus iners 64/381 (16.8%), identified with a confidence value of 99.9%. Gardnerella vaginalis was identified in 74/381 (19.4%) patients.Conclusions: In this proof-of-concept study we found that MALDI-TOF MS has the potential to be used to identify main Lactobacillus species directly from plates streaked with vaginal swabs.

SARS-CoV-2 is a newly-discovered positive-sense RNA virus, the cause of coronavirus disease 2019 (COVID-19) currently spreading worldwide. The SARS-CoV-2 S glycoprotein is considered a main target for neutralizing antibodies. In order to better understand the kinetics of the antibody response, we evaluated the relation between two consecutive antibody titers determined over an average period of four months. A total of 628 subjects were included in the study. A significant reduction of the antibody titers over time was found: Ab Titer 1: 8.1 Arbitrary Units (AU)/mL (IQR: 4.8-29.3); Ab Titer 2: 6.2 AU/mL (IQR: 0-28.5); p0.0001. A Receiver Operator Characteristic curve analysis showed an Area Under the Curve (AUC) of 0.973 (95% CI: 0.962-0.984; p0.0001) with an Ab titer 1 threshold of 110 AU/mL to predict an Ab Titer 2 ≥50 AU/mL with 100% specificity. Likewise, an AUC of 0.952 (95% CI: 0.930-0.974; p0.0001) with an Ab titer 1 threshold of 185 AU/mL was found to predict an Ab Titer 2 ≥100 AU/mL. This study showed that the SARS-CoV-2 S1/S2 IgG median titer declined over an average period of four months and that the first IgG determination thresholds found can help predict IgG values after the same interval.

Obiettivi: analizzare i dati di resistenza agli antibiotici raccolti dal Laboratorio di Microbiologia e Virologia dell'Azienda Ospedaliera SS. Antonio e Biagio e Cesare Arrigo di Alessandria per gli anni 2019 e 2020. Metodi: negli ultimi decenni, l’antibiotico resistenza è aumentata a livello globale, diventando una delle maggiori sfide per la salute pubblica dei giorni nostri. Il fenomeno attualmente è inserito nella lista dell’Unione Europea dei problemi sanitari speciali ed è monitorato tramite il sistema di sorveglianza EARSNet. In Italia, il sistema di sorveglianza dell’antibiotico resistenza AR-ISS, coordinato dall'Istituto Superiore di Sanità, è uno strumento essenziale per studiare e descrivere la comparsa e la diffusione del fenomeno. Il sistema di si basa su una rete di laboratori ospedalieri presenti su tutto il territorio nazionale, che inviano dati di routine sulla suscettibilità agli antibiotici per patogeni selezionati da infezioni invasive. In questo lavoro, nell'ambito della rete AR-ISS, vengono presentati i report di sorveglianza annuali 2019 e 2020 dell'Azienda Ospedaliera di Alessandria tramite statistiche riassuntive ed istogrammi. Risultati: sono state analizzate le specie batteriche sotto sorveglianza e i dati del 2020 confrontati con quelli del 2019. Inoltre, viene valutata la tendenza europea ed italiana del quinquennio 2015-2019 per quattro combinazioni farmaco/batterio. Particolare attenzione è stata rivolta a possibili previsioni di resistenza agli antibiotici. Conclusioni: i programmi di sorveglianza forniscono informazioni attuali e storiche indispensabili per una corretta stewardship antibiotica; inoltre, possibili previsioni future della resistenza agli antibiotici potrebbero essere utili per guidare le decisioni sulle strategie di mitigazione.

In Italy, a large stock of public housing was built during the 1970s and 1980s with industrialized/prefabricated techniques. These buildings have envelopes characterized by the presence of many thermal bridges and low transmittance values. In addition, they feature inefficient single heating systems in residential units and no cooling/ventilation systems. As a result, these buildings require urgent energy retrofitting actions, and it is therefore necessary to define procedures that will guarantee effective results. The possible interventions must be compatible with building construction techniques as well as be minimally invasive and inexpensive. There are only a limited number of technical solutions, considering that residents should not have to move out during the renovations. In most Italian climatic zones, current interventions are usually linked to external insulation and window replacement, leading to an improvement in energy performance and comfort only during winter. Internal comfort conditions tend to worsen in summer months because seasonal temperatures tend to increase by a few degrees. Therefore, solutions should be proposed that will improve both summer and winter conditions. This work proposes an energy recovery procedure applied to a representative building from the abovementioned period located in the Florence area and constructed with an industrialized system named the “tunnel system” (great panels structure). The procedure used in this study provides for the redevelopment of the envelope and the application of a simple mechanical ventilation system to achieve substantial energy savings and improved indoor comfort conditions.

Objectives: Evaluation of the analytical performance of the Novodiag Stool Parasites biomolecular assay for the detection of intestinal parasites in faeces of the faecal microbiota transplant donor. Methodology: Comparison between the gold standard for the diagnosis of intestinal parasites, light microscopy, and the Novodiag Stool Parasites biomolecular assay through the use of 22 fecal samples. Results: Twelve out of 22 samples were positive on microscopic examination. In order to assess the overlapping between the results obtained through parasitological examination and the molecular methodology, all samples were tested to the Novodiag Stool Parasites assay. Positive samples detected by biomolecular assay were 11 out of 22. Conclusion: The preliminary evaluation of the analytical performance of the Novodiag Stool Parasites kit can be considered promising. The Novodiag Stool Parasites kit can be effectively used as a tool in the fast diagnosis of intestinal parasitoses on the faecal microbiota transplant donor faeces.

Viruses are frequent causal agents of acute respiratory infections and the most common are influenza virus, respiratory syncytial virus (RSV), human parainfluenza virus (HPIV), human metapneumovirus (HMPV), rhinovirus (RV), adenovirus (AdV) and the four endemic human coronaviruses (HCoV) -229E, -NL63, -OC43, -HKU1. Multiplex real-time PCR platforms are becoming increasingly common in laboratories mostly in relation to the increased diagnostic sensitivity and reduced turnaround time. The aim of our study was to determine the prevalence of respiratory viruses in a population of patients within the S.S. Antonio e Biagio e Cesare Arrigo General Hospital catchment area of Alessandria, Italy, from January 2016 to June 2020. Therefore, we retrospectively analyzed the results of multiplex real-time PCR performed on nasopharyngeal swabs collected from consecutive patients with symptoms of respiratory infection. A total of 572 patients were included in the study subdivided as follows: pediatric 197/572 (34.4%), adults 200/572 (35%) and elderly 175/572 (30.6%). Among all samples, 235/572 (41.1%) were positive for a respiratory virus, of whom 189/235 (80.4%) were monomicrobial. The prevalence was: 15.5% (89/572) of rhinovirus/enterovirus (RV/EV); 9.4% (54/572) of RSV; 8.9% (51/572) of influenza virus; 5.4% (31/572) of AdV; 3.1% (18/572) of HCoV; 2.8% (16/572) of HPIV; and 2.3% (13/572) of HMPV. RV/EV were the pathogens most frequently involved in coinfections (34.7%, 16/46), followed by AdV (19.6%, 9/46) and influenza virus (19.6%, 9/46). Samples collected from the pediatric group were more frequently positive. The prevalence of positive pediatric samples compared to adults and elderly, respectively was: 28.4% (56/197) for RV/EV vs 10.5% (21/200) vs 6.9% (12/175), p0.0001; 18.8% (37/197) for RSV vs 2% (4/200) vs 7.4% (13/175), p0.0001; 13.7% (27/197) for AdV vs 1% (2/200) vs 1.1% (2/175), p0.0001; and 6.6% (13/197) for HPIV vs 0.5% (1/200) vs 1.1% (2/175), (p0.0001). With regard to seasonality, a significantly higher prevalence of influenza virus (p0.0001) and RSV (p=0.029) was found during winter, with peaks in January-February. AdV peaked during winter 2018-2019 (p=0.004), while HCoV were detected with a significantly higher prevalence during winter 2019-2020 (p=0.037). With regard to HPIV, a significant peak from summer to fall 2018 was observed (p=0.016). Most viral respiratory infections have seasonal patterns and the prevalence of respiratory viruses varies according to the method, geographic area and population considered. Knowledge of local epidemiology is therefore crucial for implementation of prevention and treatment strategies.

Light microscopy, immunochromatographic rapid diagnostic tests and molecular methods are widely used to diagnose malaria. The aim of this study was to find variables among commonly available urgent blood tests to identify patients with low probability of having malaria in small-scale healthcare facilities in which none of the described methods is feasible within a short time. Diagnosis of malaria was made by examining both stained thick and thin blood films by light microscopy. Two hundred and eleven samples were included. Reduced platelet count and increased values of C-reactive protein (CRP) and total bilirubin were the variables most strongly associated with malaria (P0.0001). The best screening cut-off values obtained by receiver operating characteristic curve analysis for a negative result for malaria were: platelets ≥185,000 cells/μl; CRP ≤2 mg/dl; total bilirubin ≤0.28 mg/dl. The logistic regression model of log-transformed variables showed how platelet count was the only independent variable related to the odds of having a negative blood film result for malaria (odds ratio: 2.621; 95% confidence interval: 1.441-4.768; P=0.002). A platelet count of ≥185,000 cells/μl can be considered a screening value to identify patients with high-probability of a negative blood film result for malaria.

Detailed, reliable, and time-saving methods to predict the transfer characteristics of horizontal-tube falling-film absorbers are critical to control system operability, such that it is closer to its technical limitations, and to optimise increasingly complex configurations. In this context, analytical approaches continue to hold their fundamental importance. This study presents an analytical solution of the governing transport equations of film absorption around a partially wetted tube. A film stability criterion and a wettability model extend the validity range of the resulting solution and increase its accuracy. Temperature and mass fraction fields are analytically expressed as functions of Prandtl, Schmidt, and Reynolds numbers as well as tube dimensionless diameter and wetting ratio of the exchange surface. Inlet conditions are arbitrary. The Lewis number and a dimensionless heat of absorption affect the characteristic equation and the corresponding eigenvalues. Consequently, local and average transfer coefficients are estimated and discussed with reference to the main geometrical and operative parameters. Finally, a first comparison with the numerical solution of the problem and experimental data from previous literature is presented to support the simplifying assumptions, which are introduced and as a first model validation.

This work presents a two-dimensional analytical solution of the governing differential equation for falling film vapour-absorption around a plain horizontal tube. The solution of the species transport equation gives the LiBr mass fraction distribution within the liquid absorptive film flowing along the tube surface and can be used to characterize the mass transfer performance of falling film absorbers or generators. By means of the inclusion of partial wetting effects at reduced solution mass flowrates, this study obtains an analytical expression of the mass transfer coefficient of these devices applicable over an extended range of operative conditions. The hypotheses of small penetration for physical absorption and constant heat flux condition are applied at the film interface to reach a closed-form solution. Fourier method is used to solve the problem and the eigenvalues obtained from the characteristic equation depend on Lewis number, Biot number and the dimensionless heat of absorption. Given the boundary condition at the wall, the two-dimensional mass fraction field of the laminar film can be expressed analytically as a function of Schmidt, Reynolds numbers, the tube dimensionless diameter and the ratio of the wetted area to the total exchange surface. Finally, mass transfer coefficient and absorbed mass flux are locally and globally investigated as functions of the influent dimensionless groups to clarify their effects on the physical process and screen the potentiality of the model. Results show notable qualitative and quantitative agreement with previous numerical solutions and experimental results from previous literature. This model constitutes a widely applicable and time-saving tool for actual system simulations, design and control.

Staphylococcus aureus is a pathogen causing infections that range from skin lesions to life threatening conditions. Methicillin resistance development in S. aureus strains represents a huge problem worldwide. The inhibition efficacy of twelve different essential oils (laurel, anise, oregano, basil, lavender, mint, rosemary, tea tree, bergamot, grapefruit, ginger and winter savory) and of the antibiotic Vancomycin was tested against S. aureus NCTC6571 and clinical isolates using paper disk diffusion assay and broth microdilution test methods. Forty-four S. aureus strains isolated from different human sample were characterized for antibiotic resistance and 41% of them were methicillin resistant. Among the twelve tested oils basil, oregano and savory showed stronger inhibition effect on S. aureus growth than Vancomycin. These results can be useful for the formulation of topical gel containing selected essential oils active against S. aureus strains.

Infectious meningitis and encephalitis are potentially life-threatening conditions caused mostly by bacterial and viral agents. Rapid diagnosis and prompt treatment are associated with a more favorable outcome. In recent years nucleic acid amplification tests have been developed to speed detection and identification of pathogens directly from cerebrospinal fluid (CSF). The aim of this study was to compare the diagnostic accuracy of a commercially available multiplex PCR assay for etiological diagnosis of infectious meningitis directly from CSF samples with culture. A secondary endpoint was to look for a possible screening threshold based on main CSF indices and urgent blood test results, to define CSF samples with low pre-test probability of PCR and/or culture-positive result. We performed a secondary analysis of results of CSF samples already processed as part of routine clinical care from February 2016 to December 2018. In all, 109 CSF samples were included in the study and a total of 14 bacteria were identified by either PCR, culture or both methods, along with nine samples positive for viruses. The comparison of PCR results with culture showed no significant difference: 7/109 (6.4%) vs 13/109 (11.9%) respectively, p=0.07. After exclusion of the isolates not detectable by the multiplex PCR panel, the diagnostic accuracy was: 100% (95% confidence interval (CI): 54.1% to 100%) sensitivity; 98.9% (95% CI: 93.5% to 99.9%) specificity; 85.7% (95% CI: 42% to 99.2%) positive predictive value; 100% (95% CI: 95.1% to 100%) negative predictive value; 96 (95% CI: 13.6 to 674.6) LR+; Zero LR-; Cohen's kappa: 0.918, p0.0001. CSF protein value ≤ 28 mg/dl and CSF glucose/blood glucose ratio ≥0.78 were associated with both PCR-negative result for bacteria or viruses and culture-negative result. The multiplex PCR evaluated in this study showed a very good diagnostic performance compared to culture, and the thresholds found can be a useful tool to best choose which samples to test.

Research activity on ejectors is ongoing at the University of Florence since the late nineties. The most important achievement is a 40 kW ejector chiller designed according to the “CRMC” criterion. The experimentally validated CFD simulations have given some hints about some possible improvements, i.e. refine the surface finish of the ejector, study the effect of heat transfer and improve the final part of the diffuser, which in its present shape does not produce a measurable compression. The prototype has been recently filled with low-GWP refrigerant R1233zd, as a drop-in replacement of previously used R245fa. Both fluids are “dry-expanding” and hence significantly easier to model in CFD simulations. Synthetic low-GWP refrigerants may be an option for ejector chillers, due to their ability to reach below-zero temperature and high volumetric refrigerant capacity. Some lessons learned with synthetic refrigerants can be transferred to the project of a steam ejector chiller, which remains one of our future targets. Herein we resume the principal findings gathered by means of experimental and numerical activity on our prototype and propose a few ideas for the future research.

In the context of “2030 climate & energy framework” and “2050 low-carbon economy” it is essential to understand which the elements that affect most buildings energy needs are. The main aim of this study is to identify and to optimize these factors in order to improve energy performance of schools by minimizing energy consumption. The study presented was carried out through a sensitivity analysis in order to determine which factors most affect energy consumption with respect a school typological model adopted as the reference model considering climate zones D and B. The analysis evaluated: shape, different materials for insulation, thickness of insulation layer for façade and for roof, window to wall ratio (WWR) for each orientation, type of solar shading for south orientation, integration of vertical solar shading for east and west orientation, contribution of ventilation and some parameters related to systems. Results pointed out that for this type of buildings the ventilation requirements for air changes is the factor that most affects the energy demand both for heating and cooling. At the same time also the variation of shape, of thickness insulation layer for roof and of WWR influence is significant.

A new general thermodynamic mapping of desiccant systems&rsquo, performance is conducted to estimate the potentiality and determine the proper application field of the technology. This targets certain room conditions and given outdoor temperature and humidity prior to the selection of the specific desiccant material and technical details of the system configuration. This allows the choice of the operative state of the system to be independent from the limitations of the specific design and working fluid. An expression of the entropy balance suitable for describing the operability of a desiccant system at steady state is obtained by applying a control volume approach, defining sensible and latent effectiveness parameters, and assuming ideal gas behaviour of the air-vapour mixture. This formulation, together with mass and energy balances, is used to conduct a general screening of the system performance. The theoretical advantage and limitation of desiccant dehumidification air conditioning, maximum efficiency for given conditions constraints, least irreversible configuration for a given operative target, and characteristics of the system for a target efficiency can be obtained from this thermodynamic mapping. Once the thermo-physical properties and the thermodynamic equilibrium relationship of the liquid desiccant mixture or solid coating material are known, this method can be applied to a specific technical case to select the most appropriate working medium and guide the specific system design to achieve the target performance.

Risk assessment, environmental monitoring, and the disinfection of water systems are the key elements in preventing legionellosis risk. The Italian Study Group of Hospital Hygiene of the Italian Society of Hygiene, Preventive Medicine, and Public Health and the Italian Multidisciplinary Society for the Prevention of Health Care-Associated Infections carried out a national cross-sectional survey to investigate the measures taken to prevent and control legionellosis in Italian hospitals. A multiple-choice questionnaire was developed, comprising 71 questions regarding hospital location, general characteristics, clinical and environmental surveillance, and control and preventive measures for legionellosis in 2015. Overall, 739 hospitals were enrolled from February to June 2017, and 178 anonymous questionnaires were correctly completed and evaluated (response rate: 24.1%). The survey was conducted using the SurveyMonkey® platform, and the data were analyzed using Stata 12 software. Of the participating hospitals, 63.2% reported at least one case of legionellosis, of which 28.2% were of proven nosocomial origin. The highest case numbers were reported in the Northern Italy, in hospitals with a pavilion structure or cooling towers, and in hospitals with higher numbers of beds, wards and operating theaters. Laboratory diagnosis was performed using urinary antigen testing alone (31.9%), both urinary antigen testing and single antibody titer (17.8%), or with seroconversion also added (21.5%). Culture-based or molecular investigations were performed in 28.8% and 22.1% of the clinical specimens, respectively. The water systems were routinely tested for Legionella in 97.4% of the hospitals, 62% of which detected a positive result (> 1000 cfu/L). Legionella pneumophila serogroup 2–15 was the most frequently isolated species (58.4%). The most common control measures were the disinfection of the water system (73.7%), mostly through thermal shock (37.4%) and chlorine dioxide (34.4%), and the replacement (69.7%) or cleaning (70.4%) of faucets and showerheads. A dedicated multidisciplinary team was present in 52.8% of the hospitals, and 73% of the hospitals performed risk assessment. Targeted training courses were organized in 36.5% of the hospitals, involving nurses (30.7%), physicians (28.8%), biologists (21.5%), technicians (26.4%), and cleaners (11%). Control and prevention measures for legionellosis are present in Italian hospitals, but some critical aspects should be improved. More appropriate risk assessment is necessary, especially in large facilities with a high number of hospitalizations. Moreover, more sensitive diagnostic tests should be used, and dedicated training courses should be implemented.

Based on a numerical study of the water vapour absorption process in LiBr–H 2 O solution, for a laminar, gravity driven, viscous, incompressible liquid film, flowing over a horizontal cooled tube, irreversibilities related to fluid friction, heat transfer, mass transfer and their coupling effects have been locally and globally examined. The hydrodynamic description is based on Nusselt boundary layer assumptions. The tangential and normal velocity components, respectively obtained from momentum and continuity equations, have been used for the numerical solution of mass and energy transport equations in the two-dimensional domain defined by the film thickness and the position along the tube surface. Local entropy generation calculation can be performed referring to the calculated velocity, temperature and concentration fields. Results have been explored in different operative conditions, in order to examine comprehensively the impact of the various irreversibility sources and to identify the least irreversible solution mass flow-rate for the absorber. As a parallel, a refined understanding of the absorption process can be obtained. Considering absorption at the film interface and cooling effect at the tube wall, the analysis thermodynamically characterises the absorption process which occurs inside actual falling film heat exchangers and establishes a criterion for their thermodynamic optimisation. Results suggest the importance to operate at reduced mass flow rates with a thin uniform film. Meanwhile, tension-active additives are required to realise this condition.

The Constant Rate of Momentum Change (CRMC) criterion attempts to improve the design of supersonic ejectors, that can be used in heat-powered chillers for industrial or air-conditioning use. Moving from its original formulation, the CRMC design method can be advanced accounting for friction irreversibilities and real gas behaviour, as done in a previous work by our research group. Here we present an upgraded version of this analysis, supported by experimental data from a prototype chiller using R245fa as working fluid. The analysis is extended to other fluids (water, isobutane, 5 HFCs and 3 HFOs) whose performance is calculated on a wide range of heat source/sink temperatures. The existing literature, based generally on ideal gas simulations, suggests that water yields poor results in terms of COP. This paper shows that this result may be argued. Low GWP fluid HFO1233zd also gives good results.

Ejector refrigeration has been studied at DIEF (Dipartimento di Ingegneria Industriale Firenze) since the ‘90s. Use of environmentally safe fluids (steam) was addressed. A two-stage prototype with cooling capacity 5 kW was optimized and built. Later, the CRMC prescription for the design of the supersonic diffuser was focused. By a gradual reduction of the fluid velocity and a continuous profile, the CRMC design promises a reduction of the normal shock that usually develops in the mixing chamber. A second 40 kWf prototype was designed in 2010 for an industrial partner (Frigel Firenze s.p.a.). The design procedure used a thermodynamic code accounting for real gas behavior. This code gives a first design of the mixing chamber and diffuser according to the CRMC criterion. It also gives an estimation of the friction loss along the diffuser. A comparison between different operating fluids was performed and resulted in the selection of R245fa. A first design of the ejector was manufactured in carbon fiber. The primary nozzle is mounted on a movable support, in order to change its axial position with respect to the mixing chamber. In terms of COP, first results were below the values predicted by the simulation code. Meanwhile a numerical simulation was in progress with FLUENT. From the first CFD results it was decided that the diffuser throat had to be moved forward from the primary nozzle exit, in order to allow a complete mixing between the primary and secondary flows, and enlarged, the losses encountered in the mixing process being higher than expected and hence the fluid density lower. This produced a second ejector design, which was manufactured and tested in 2012, showing improved performance. These results suggested a third design, with a further lengthened diffuser, which has undergone a complete testing campaign, allowing validation of the CFD results. The activity performed till now suggests that ejector refrigeration plants have a robust operation and can be easily manufactured at relatively low cost with off-the-shelf components, a part from the ejector itself, which however represents a small fraction of the system cost. However, the COP is lower with respect to absorption refrigeration and hence needs substantial improvement through detailed thermodynamic and CFD design optimization.

Salmonella bongori 48:z35:– is considered endemic to Sicily (Italy) due to its epidemiological peculiarity. To our knowledge, no previous cases of human infection caused by S. bongori 48:z35:– have ever been reported in mainland Italy. Here we describe the isolation of S. bongori 48:z35:– from a 1-year-old symptomatic child in northwest Italy (Piedmont Region). The strain showed no antimicrobial resistance. Reporting of S. bongori 48:z35:– in a previously safe area is important to identify epidemiological changes.

A local entropy generation analysis, for water vapor absorption in LiBr-H 2 O solution, is performed referring to velocity, temperature and concentration fields obtained from the numerical solution of mass and energy transport equations. The hydrodynamic description is based on Nusselt boundary layer assumption and the actual amount of irreversibility introduced is determined for an absorptive falling film over a cooled horizontal tube inside the absorber. Results are explored in different operative conditions in order to examine the impact of the various irreversibility sources in a wide operative range. A least irreversible solution mass flow-rate can always be identified. Furthermore, a simple and general thermodynamic analysis, carried out regarding a refrigerating and a heat boosting applications, makes evidence of a dimensionless group “Q/σT” that separates the weight of the irreversibilities and gives the way to an optimization criterion applied to the absorber in order to improve the whole system efficiency. Both thermodynamic equilibrium and sub-cooling conditions of the solution at the inlet are considered for typical temperature and concentration of refrigerators' absorbers and heat transformers' absorbers. Results suggest the importance to work at reduced mass flow-rates with a thin uniform film. In practice, tension-active additives are required to realize this condition. Also, it is highlighted that the two parameters defined with reference to the dimensionless group “Q/σT” can be maximized by specific values of the tube radius, operative Reynolds number, solution sub-cooling and temperature difference between the wall and the inlet solution.

To investigate the role of suPAR in patients with sepsis admitted to the Emergency Department (ED). We performed multicentre prospective trial including patients admitted to the ED of three different Italian hospitals. Patients were studied upon admission on day 1, 2, 4 and 7. They were subdivided into two groups: sepsis (group 1) and severe sepsis or septic shock (group 2). The two groups were comparable for age, gender and CRP level on day 1. Patients with severe sepsis or septic shock displayed significantly higher baseline levels of suPAR, PCT and lactate. In both groups, suPAR decreased across the time (p < 0.0005). Group 1 was not different from group 2 (p = 0.545) in mortality at 7 days, while group 2 had higher mortality at 30 days than group 1 (p = 0.022). At the multivariate analysis, lactate1 (p = 0.012) and age (p = 0.019) were independent predictors of mortality at 7 days, whereas suPAR1 (p = 0.023) and age (p = 0.032) were independent predictors of mortality at 30 days. Lactate and suPAR resulted the most predictive biomarkers in the risk stratification of patients with suspected infection initially admitted to the ED, according to their role in predicting 7- and 30-day mortality, respectively.

The authors evaluated the performance of the MycArray™ Yeast ID (Myconostica Ltd, UK) assay in the identification of a total of 88 yeast isolates recovered in culture as compared to that obtained through routine methods. The turn-around time for species identification directly from cultures by the MycArray was 6 hours, much quicker than classical methods and all yeasts were correctly identified. In two cases a double identification including Saccharomyces cerevisiae was noted, but it was not confirmed by culture. The results show that MycArray Yeast ID can be a potential tool for rapid detection and identification of Candida species.

Absorption heat transformers extend the possibilities for efficient and environment-friendly energy conversion processes. Based on a general thermodynamic model of three-thermal cycles with finite thermal capacity of the heat sources, this paper is intent upon analyzing and optimizing the performance of absorption heat transformers, by including the influence of irreversibility in the analytical expression of the system efficiency. Dimensionless parameters for an overall optimization are defined and a first screening is performed to clarify their influence. Dependence on the main factors is highlighted to suggest how to change them in order to enhance the whole system performance. Under this point of view, the analysis evaluates coefficient of performance (COP) improvements and can be used to perform existing plant diagnostics, besides predicting the system performance. The use of this criterion is exemplified for specific heat transformers data from literature. This approach identifies the limitations imposed to the physical processes by accounting for the inevitable dissipation due to their constrained duration and intensity, and constitutes a general thermodynamic criterion for the optimization of three-thermal irreversible systems.