An evaluation of R22 substitutes performances regulating continuously the compressor refrigeration capacity

This paper presents the results of an experimental analysis which compares in terms of energetic performances the refrigeration capacity control obtained by means of a variable-speed compressor with the on/off control deriving from a classical thermostatic device. The compressor considered is semi-hermetic reciprocating and is a component of a vapour compression refrigeration plant subjected to a commercially available cold store. The compressor working with the fluids R22, R507 and R407C and designed for a revolution speed corresponding to the compressor supply current nominal frequency of 50 Hz, has been tested varying the frequency in the range 30–50 Hz. In this range, the most suitable working fluids proposed as substitutes of the R22 as the R407C (R32/R125/R134a 23/25/52% in mass), the R507 (R125/R143A 50/ 50% in mass) and the R417A (R125/R134a/R600 46.6/50/3.4% in mass) have been tested. The results show that, using the R407C, it is possible an average an electric energy consumption about 12% smaller when an inverter is employed to control the compressor refrigeration capacity instead of the thermostatic control which imposes on/off cycles on the compressor, working at the nominal frequency of 50 Hz. So the R407C confirms its superiority in comparison with the R417A and R507; only the R22 shows a better performance

Hydrodynamic Characterization of GULF STREAM Circulation in a Pilot Scale Fluidized Bed Combustor

The present study addresses the hydrodynamics of a pilot-scale fluidized bed combustor with a focus on the establishment of "Gulf Stream" circulation patterns as a solids mixing promoter. Time-resolved pressure signals measured at different locations in the bed and in the plenum were analyzed in the time, frequency and phase-space domains. Results were matched against qualitative characterization of fluidization patterns by visual observation of the bed surface

Zeolite-based monoliths for water softening by ion exchange/precipitation process

In this work, the design of a monolithic softener obtained by geopolymer gel conversion is proposed. The softener used consists in a geopolymeric macroporous matrix functionalized by the co-crystallization of zeolite A and X in mixture. The dual nature of the proposed material promotes a softening process based on the synergistic effect of cation exchange and alkaline precipitation. A softening capacity of 90% and 54% for Ca2+ and Mg2+ respectively was attained in 24 h. In fact, the softener reported a Cation Exchange Capacity (CEC) value of 4.43 meq g−1. Technical features such as density, porosity and mechanical resistance were also measured. The use of this monolithic softener can improve performance and sustainability of hardness removal from tap water, reducing the production of sludge and adding the possibility to partially regenerate or reuse it

Phylogeographyc inferences from the mtDNA variation of the three-toed skink, Chalcides chalcides (Reptilia: Scincidae)

Genetic diversity was analyzed in Chalcides chalcides populations from peninsular Italy, Sardinia, Sicily and Tunisia by sequencing 400 bp at the 50 end of the mitochondrial gene encoding cytochrome b (cyt b) and by restriction fragment length polymorphism (RFLP) analysis of two mitochondrial DNA segments (ND-1/2 and ND-3/4). The results of the phylogenetic analysis highlighted the presence of three main clades corresponding with three of the four main geographical areas (Tunisia, Sicily and the Italian peninsula), while Sardinia proved to be closely related to Tunisian haplotypes suggesting a colonization of this island from North Africa by human agency in historical times. On the contrary, the splitting times estimated on the basis of cyt b sequence data seem to indicate a more ancient colonization of Sicily and the Italian Peninsula, as a consequence of tectonic and climatic events that affected the Mediterranean Basin during the Pleistocene. Finally, the analysis of the genetic variability of C. chalcides populations showed a remarkable genetic homogeneity in Italian populations when compared to the Tunisian ones. This condition could be explained by a rapid post-glacial expansion from refugial populations that implied serial bottlenecking with progressive loss of haplotypes, resulting in a low genetic diversity in the populations inhabiting the more recently colonized areas

Plasma-arc-flow technology for sustainable treatment of high-impact fluid waste. A graphene-based material for industrial-wastewater purification

The research presented aimed to address the treatment of fluid waste with significant environmental impact by utilizing plasma technology, specifically plasma arc flow (PAF). The goal was to develop a novel purification material based on graphene for industrial applications and to optimize the treatment process. Analysis and monitoring of a submerged arc plasma reactor were the main goals of this research. This entailed a careful examination of the incoming wastewater that needed to be treated with the goal of identifying its precise composition characteristics with the relative tolerances needed for the reactions that were to follow in the reactor. The focus of the analysis was on input-parameter optimization, production of characteristic curves, and analysis of the factors affecting hydrogen evolution in syngas. Additionally, the study investigated how to determine the best viscosity for a particular input matrix by carrying out an evaluation study. The effects of this parameter were thought to be reduced by preheating the incoming wastewater through heat recovery. The long-term objective of the research is to create filters that can purify the water used and produced in gasification processes as well as to characterize the fixed reside from the gasifier for potential conversion into graphene-based material. In addition, this work acknowledges that additional experiments are required to validate its purifying capacity on wastewater produced by various industrial processes. Moreover, the inclusion of plans to model the evolution of hydrogen in PAF using the CHEMCAD software® and defining guidelines for optimizing parameters for enhanced energy efficiency showcased the research’s ambition to expand and refine its scope. Finding the best plant solutions that can significantly reduce electricity consumption is the ultimate goal. In summary, the study demonstrated significant advancement in the analysis and optimization of fluid-waste treatment with high environmental impact through the use of plasma technology, specifically PAF. A thorough and forward-looking approach was demonstrated by the use of modeling software, experimental studies, and plans for future research. The potential creation of graphene-based filters and the use of the fixed residue as a useful material further highlight the innovativeness of this research

Polypoid vascular malformation of the small intestine.

A 56-year-old man underwent capsule endoscopy because of obscure GI bleeding. Capsule endoscopy showed a pink and somewhat nodular polypoid lesion of the small bowel partially obstructing the intestinal lumen (A). The patient underwent an ileal resection and the operative specimen showed loss of mucosal folds and the presence of an erythematous area with a polypoid formation of 3.5 × 3 cm (B). Histologic examination revealed the presence of numerous ectatic thin-walled blood vessels and a small number of thick-walled vessels in the submucosa (C and D, arrows; H&E, orig. mag. ×4), surrounded by hypertrophic muscularis mucosae and a chronic inflammatory infiltrate that infiltrated the muscularis propria; the diagnosis of polypoid angiodysplasia was suggested. There has been no recurrence of GI bleeding 14 months after the ileal resection

Tailoring chitosan/lta zeolite hybrid aerogels for anionic and cationic dye adsorption

Chitosan (CS) is largely employed in environmental applications as an adsorbent of anionic dyes, due to the presence in its chemical structure of amine groups that, if protonated, act as adsorbing sites for negatively charged molecules. Efficient adsorption of both cationic and anionic dyes is thus not achievable with a pristine chitosan adsorbent, but it requires the combination of two or more components. Here, we show that simultaneous adsorption of cationic and anionic dyes can be obtained by embedding Linde Type A (LTA) zeolite particles in a crosslinked CS‐based aerogel. In order to optimize dye removal ability of the hybrid aerogel, we target the crosslinker concentration so that crosslinking is mainly activated during the thermal treatment after the fast freezing of the CS/LTA mixture. The adsorption of isotherms is obtained for different CS/LTA weight ratios and for different types of anionic and cationic dyes. Irrespective of the formulation, the Langmuir model was found to accurately describe the adsorption isotherms. The optimal tradeoff in the adsorption behavior was obtained with the CS/LTA aerogel (1:1 weight ratio), for which the maximum uptake of indigo carmine (anionic dye) and rhodamine 6G (cationic dye) is 103 and 43 mg g−1, respectively. The behavior observed for the adsorption capacity and energy cannot be rationalized as a pure superposition of the two components, but suggests that reciprocal steric effects, chemical heterogeneity, and molecular interactions between CS and LTA zeolite particles play an important role

Peripheral blood mono-nuclear cells implantation in patients with Peripheral Arterial Disease: a pilot study for clinical and biochemical outcome of neoangiogenesis.

BACKGROUND: Substantial progresses in the management of peripheral arterial disease (PAD) have been made in the past two decades. Progress in the understanding of the endothelial-platelet interaction during health and disease state has resulted in better antiplatelet drugs that can prevent platelet aggregation, activation and thrombosis during angioplasty and stenting. A role in physiological and pathological angiogenesis in adults has been recently shown in bone marrow–derived circulating endothelial progenitors (BM-DCEPs) identified in the peripheral blood. These findings have paved the way for the development of therapeutic neovascularization techniques using endothelial progenitors. METHODS: This pilot study includes five patients, aged 60 to 75, with a history of claudication and recruited from September 2010 to February 2011 at the A.O.U. Federico II of Naples. PBMNCs have been implanted three times in the limb with the worst ABI value in all the patients included in the study. The clinical follow up was performed during the subsequent 12 months from the beginning of the treatment. RESULTS: In four patients there was a regression of ulcerative lesions. One patient’s condition improved after the first implantation but later did not respond to the further treatments. All patients achieved a pain relief as judged by the numeric pain scale. Pain relief remained satisfactory in three patients for one year. Pain gradually returned to the pre-treatment level in two patients. All patients referred an ameliorating in their quality of life expressed even by an improvement in claudication free walking distance. These improvements are reflected also by intra-arterial digital subtraction angiography (IADSA) that shows an improvement of arterial vascularization. CONCLUSIONS: The data from this study suggest an efficacy of BM-DCEPs implantation in terms of improvement of the vascularization and quality of life in patients affected by Peripheral Arterial Disease. Nevertheless a double-blind placebo-controlled study is needed to confirm our findings

Economic burden of diverticular disease : an observational analysis based on real world data from an Italian region

INTRODUCTION: Diverticular disease (DD), a herniation of the colonic mucosa through the muscle layer, covers a wide variety of conditions associated with the presence of diverticula in the colon. The most serious form is an acute episode of diverticulitis, which can lead to hospitalization and surgery with various types of consequences. The main aim of this study is to evaluate the economic burden of hospitalizations arising from acute episodes of diverticulitis using data from the administrative databases used in the Marche region in Italy and, as a secondary objective of this real-world data analysis, to study patient outcome variables following initial hospitalization for diverticulitis. METHOD: A deterministic linkage was performed at individual user level between the different administrative sources of the Marche region through anonymous ID number for a period of analysis between 1 January, 2008 and 31 December, 2014. We enrolled all patients with at least one hospitalization for "diverticulitis of the colon without mention of haemorrhage" (ICD-9-CM code 562.11) or "diverticulitis of the colon with haemorrhage" (ICD-9-CM code 562.13) as primary or secondary diagnosis. For each patient we assessed the cost of hospitalization, of medicines and of specialist services considering a time-scale of one year or cohort analysis 365days after first admission. RESULTS: The total number of residents in the Marche region who had at least one hospitalization for diverticulitis in the period 2008-2014 was 2987 (427 patients a year, corresponding to about 35 patients per 100,000 adult residents); the total number of admissions was 3453 (just over 490 a year). The direct healthcare costs incurred by the Marche region for episodes of diverticulitis in 2008-2014 amounted to approximately €11.4 million (€1.6 million a year), of which €10.9 million (95.5%) for the hospitalizations, € 246,000 (2.1%) for pharmaceutical treatment and €270,000 (2.4%) for specialist outpatient services. The average annual cost per patient was €3826, of which €3653 was for hospitalization, while pharmaceutical expenditure and specialist services accounted for €83 and €90, respectively. The cohort of patients undergoing a first admission for diverticulitis between 2010 and 2013 was made up of 1729 people (54.4% women, mean age 68.9 years), of whom 1500 (86.8%) did not undergo surgery while in hospital. Hospital mortality, recorded only for the over-65 age class, averaged 1.2%; for patients not receiving surgery during the initial hospitalization it was 0.5%, reaching 5.2% in patients undergoing surgery. The percentage of patients with one or more readmissions for diverticulitis within a year of the first was on average 7.8% and in 48% of cases this resulted in surgery. CONCLUSIONS: Our study is the first analysis in Italy to use real-world data to measure the financial impact of diverticular disease. Assuming that the diagnostic and therapeutic behaviour identified in the Marche region could be representative of the situation nationwide, the estimated annual number of hospitalizations in Italy for acute episodes of diverticulitis is 19,000. The total amount of economic resources needed to treat patients suffering from acute episodes of diverticulitis is estimated at €63.5 million a year

Robotic colorectal cancer surgery. How to reach expertise? a single surgeon-experience

The complexity associated with laparoscopic colorectal surgery requires several skills to overcome the technical difficulties related to this procedure. To overcome the technical challenges of laparoscopic surgery, a robotic approach has been introduced. Our study reports the surgical outcomes obtained by the transition from laparoscopic to robotic approach in colorectal cancer surgery to establish in which type of approach the proficiency is easier to reach. Data about the first consecutive 15 laparoscopic and the first 15 consecutive robotic cases are extracted, adopting as a comparator of proficiency the last 15 laparoscopic colorectal resections for cancer. The variables studied are operative time, number of harvested nodes, conversion rate, postoperative complications, recovery outcomes. Our analysis includes 15 patients per group. Our results show that operative time is significantly longer in the first 15 laparoscopic cases (p = 0.001). A significantly lower number of harvested nodes was retrieved in the first 15 laparoscopic cases (p = 0.003). Clavien Dindo I complication rate was higher in the first laparoscopic group, but without a significant difference among the three groups (p = 0.09). Our results show that the surgeon needed no apparent learning curve to reach their laparoscopic standards. However, further multicentric prospective studies are needed to confirm this conclusion