Search

Two hundred thirty-seven patients were eligible for the study; however 47 of them were excluded (30 patients did not undergo LUS at admission and 17 underwent LUS but incomplete reports made them not suitable for attribution of LUS scores). As shown, literature on LUS in COVID-19 patients is rapidly growing; however few studies evaluated the prognostic value of LUS in COVID-19 patients [[20]]. These data together with the known practical advantages of being repeatable and quickly performed at bedside (thus limiting infectious patient transportation) confirm the potentiality of LUS in aiding the clinician in the risk stratification of the patient with COVID-19 pneumonia. [Extracted from the article]

Background: Attacks of Hereditary Angioedema due to C1-inhibitor deficiency (C1-INH-HAE)are often triggered by stressful events/hormonal changes. Objective: Our study evaluates the relationship between autonomic nervous system (ANS) and contact/complement system activation. Methods: Twenty-three HAE patients (6 males, mean age 47.5±11.4 years) during remission and 24 healthy controls (8 males, mean age 45.3±10.6 years) were studied. ECG, beat-by-beat blood pressure, respiratory activity were continuously recorded during rest (10’) and 75-degrees-head-up tilt (10’). C1-INH, C4, cleaved high molecular weight kininogen (cHK) were assessed; in 16 patients and 11 controls plasma catecholamines were also evaluated. Spectral analysis of heart rate variability allowed extraction of low-(LF) and high-(HF) frequency components, markers of sympathetic and vagal modulation respectively. Results: HAE patients showed higher mean systolic arterial pressure (SAP) than controls during both rest and tilt. Tilt induced a significant increase in SAP and its variability only in controls. Although sympathetic modulation (LFnu) increased significantly with tilt in both groups, LF/HF ratio, index of sympathovagal balance, increased significantly only in controls. At rest HAE patients showed higher noradrenaline values (301.4±132.9 pg/ml vs 210.5±89.6pg/ml, p = 0.05). Moreover, in patients tilt was associated with a significant increase in cHK, marker of contact system activation (49.5 ± 7.5% after T vs 47.1 ± 7.8% at R, p = 0.01). Conclusions: Our data are consistent with altered ANS modulation in HAE patients, i.e. increased sympathetic activation at rest and blunted response to orthostatic challenge. Tilt test-induced increased HK cleavage suggests a link between stress and bradykinin production. [ABSTRACT FROM AUTHOR]

In conventional aircraft energy systems, self-regulating pneumatic valves (SRPVs) are used to control the pressure and mass flow of the bleed air. The dynamic behaviour of these valves is complex and dependent on several physical phenomena. In some cases, limit cycles can occur, deteriorating performance. This article presents a complex multi-physical model of SRPVs implemented in Modelica. First, the working principle is explained, and common challenges in control-system design-problems related to these valves are illustrated. Then, a Modelica-model is presented in detail, taking into account several physical domains. It is shown, how limit cycle oscillations occurring in aircraft energy systems can be reproduced with this model. The sensitivity of the model regarding both solver options and physical parameters is investigated. [ABSTRACT FROM AUTHOR]

Inview of the increasing share of electricity produced by renewableenergy sources, transient operation of decarbonized power plants isgaining more relevance. This is due to the inherent fluctuating operationof wind or solar plants. Accurate physically based dynamic modelsare important tools to study the interaction between power plant andCO2capture unit during dynamic operation. Moreover, suchmodels are indispensable to design appropriate control systems aimedat improvement of dynamic performance. This paper documents the developmentof dynamic components as well as system models of a precombustionCO2capture unit applied to integrated gasification combinedcycle (IGCC) systems following an object-oriented modeling approach.The models have been implemented by means of the Modelica languageinto an open source software library. The fluid properties are computedwith accurate thermodynamic models implemented within an in-houseproperty package which is interfaced with the Modelica process models.Comprehensive model validation has been performed at component, subsystem,and system level by comparison against experimental measurements obtainedfrom various open- and closed-loop transient tests at the CO2capture pilot plant situated at the Buggenum IGCC power station.Results are in satisfactory agreement, considering the main processmass flow and temperature variables. To demonstrate the use of validated,dynamic process models, a control design study is presented wherebya control strategy based on feed-forward, feed-back, and cascade controlhas been implemented and tested with the aim to improve dynamic performanceof the capture unit. It can be concluded that prompt syngas load variationis a feasible operating mode for precombustion CO2captureunits featuring sophisticated control systems. The software librarycontaining the validated component and system models serves as a reliablefoundation for the development of large-scale precombustion captureunit models. [ABSTRACT FROM AUTHOR]

New promising applications of organic Rankine cycle (ORC) technology, e.g., concentrated solar power, automotive heat recovery and off-grid distributed electricity generation, demand for more dynamic operation of ORC systems. Accurate physically-based dynamic modeling plays an important role in the development of such systems, both during the preliminary design as an aid for configuration and equipment selection, and for control design and optimization purposes. A software library of modular reusable dynamic models of ORC components has been developed in the MODELICA language and is documented in the paper. The model of an exemplary ORC system, namely the 150 kWe Tri-O-Gen ORC turbogenerator is validated using fen, carefully conceived experiments. The simulations are able to reproduce steady-state and dynamic measurements of key variables, both in nominal and in off-design operating conditions. The validation of the library opens doors to control-related studies, and to the development of more challenging dynamic applications of ORC power plants. [ABSTRACT FROM AUTHOR]

Abstract: In this paper the development of an adequate modelling and simulation tool for Dynamics and Control tasks is presented. The key features of the developed simulator are: “Modularity” – the system model is built by connecting the models of its components, which are written independently of their boundary conditions; “Openness” – the code of each component model is clearly readable and close to the original equations and easily customised by the experienced user; “Efficiency” – the simulation code is fast; “Tool support” – the simulation tool is based on reliable, tested and well-documented software. To achieve these objectives, the Modelica language was used as a basis for the development of the simulator. The Modelica language is the result of recent advances in the field of object-oriented, multi-physics, dynamic system modelling. The language definition is open-source and it has already been successfully adopted in several industrial fields. The test bed for the application of the object-oriented approach has been the new generation, integral type, IRIS nuclear reactor. IRIS (International Reactor Innovative and Secure) is a pressurized light water cooled, small/medium power (335 MWe) reactor reactor, under development by an international consortium of nineteen organizations from ten countries. The preliminary design has been completed and the pre-application licensing process with the US-Nuclear Regulatory Commission (NRC) is underway. To provide the required capabilities for the analysis, specific models for the nuclear reactor components have been developed, to be applied for the dynamic simulation of the IRIS integral reactor, albeit keeping general validity for PWR plants. The following Modelica models have been written to satisfy the IRIS modelling requirements and are presented in this paper: point reactor kinetic, fuel heat transfer, control rods model, and a once-through type steam generator, thus obtaining a specific library of nuclear models and components. As far as other classical power generation plant components are concerned, the Thermo Power open library, developed at Politecnico di Milano as well, has been adopted and is briefly presented in the paper. Originally conceived for conventional, fossil-fired plants, the highly modular approach allowed to effectively reuse the models of the balance of plant systems, which have been connected to the models of the nuclear power generation process, to obtain a system simulator for the IRIS reactor. Finally, preliminary results of the code validation process and the reactor dynamics are presented. [Copyright &y& Elsevier]

Background: Between 1987 and 1994, several studies demostrated transthoracic echocardiography (TTE) to be less sensitive than transesophageal echocardiography (TEE) in detecting native valve endocarditis. Recent technologic advances, especially the introduction of harmonic imaging and digital processing and storage, have improved TTE image quality. The aim of this study was to determine the diagnostic accuracy of contemporary TTE. Methods: Between 2003 and 2007, 75 patients underwent both TTE and TEE for clinically suspected infective endocarditis. The diagnostic accuracy of TTE was assessed using transesophageal echocardiography as the gold standard for diagnosis of endocarditis. Results: Of the 75 patients in this study, 33 were found to be positive by TEE. The sensitivity for detection of infective endocarditis by TTE was 81.8%. It provided good image quality in 81.5% of cases; in these patients sensitivity was even greater (89.3%). Conclusion: Contemporary TTE has improved the diagnostic accuracy of infective endocarditis by ameliorating image quality; it provides an accurate assessment of endocarditis and may reduce the need for TEE. [ABSTRACT FROM AUTHOR]

Abstract: The use of Keplerian or Equinoctial parameters instead of Cartesian coordinates as state variables in object-oriented spacecraft models is introduced in this paper. The rigid body model of the standard MultiBody library is extended by adding transformation equations from Keplerian or Equinoctial parameters to Cartesian coordinates, and by setting the former as preferred states, instead of the latter. The remaining parts of the model are left untouched, thus ensuring maximum re-usability of the model itself. The results shown in the paper demonstrate the superior accuracy and speed of computation both in the case of a point-mass gravity field, and in the case of more accurate gravity field models. [Copyright &y& Elsevier]

Abstract: In this paper, model predictive control (MPC) is applied to the Italian 80MWth experimental accelerator driven system (XADS), referring to a simple, non-linear model for the dynamic simulation of the plant, which has been developed and described in a previous work [A. Cammi, L. Luzzi, A.A. Porta, M.E. Ricotti, Prog. Nucl. Energ. 48 (2006) 578], in order to describe the interactions among the different subsystems: i.e., the accelerator-core coupling, the lead bismuth eutectic (LBE) primary system, the secondary system with diathermic oil and air coolers batteries, which reject the thermal power to the environment. Hereinafter, a model predictive controller is proposed, with the objective to minimize the difference between the average temperature of the diathermic oil and its reference value, while also minimizing the variations of the control input, which is the air coolers mass flow rate. The dynamic response of the LBE–XADS has been evaluated with reference to a reduction of 20% in the reactor power from nominal load conditions: this transient is very demanding for the overall plant, nevertheless the obtained results indicate the effectiveness of the proposed controller. [Copyright &y& Elsevier]

The paper describes the derivation of finite-element models of one-dimensional fluid flows with heat transfer in pipes, using the Galerkin/least-squares approach. The models are first derived for one-phase flows, and then extended to homogeneous two-phase flows. The resulting equations have then been embedded in the context of object-oriented system modelling; this allows one to combine the fluid flow model with a model for other phenomena such as heat transfer, as well as with models of other discrete components such as pumps or valves, to obtain complex models of heat exchangers. The models are then validated by simulating a typical heat exchanger plant. [ABSTRACT FROM AUTHOR]

The paper discusses current approaches to the modelling and simulation of thermo-hydraulic processes, to be used as a tool for system studies in thermal power plant control. After reviewing the desirable features of simulation environments, an approach based on the Modelica language is presented and motivated. Finally, the general concepts presented above are exemplified by modelling a simple process based on a heat exchanger. [ABSTRACT FROM AUTHOR]

The main results of the simulation study of a double-flash geothermal plant, including a steam-CO2 re-boiler-based separation process, are presented. Dynamic models of two-phase, H2O-CO2 components are derived, and their use for dynamic simulation and operating point optimization is discussed. Control system issues are then considered. On one hand, the simulator is used as an aid to design and test standard level and pressure control loops, whose actual performance would otherwise be difficult to predict due to the high degree of interconnection of the plant components. On the other hand, the control concept for the innovative part of the plant is discussed, recognizing that the control problem and the operating point optimization problems have to be tackled simultaneously. A simple, yet effective, solution for this problem is proposed. [ABSTRACT FROM AUTHOR]

• Only the initial guesses of variables affecting the Jacobian of a nonlinear system of equations influence the convergence of Newton's method. • Sufficient conditions for the reduction of the residuals after the first iteration of Newton's method are given. • Numerical indicators are defined to highlight which initial guesses of Newton's method are farthest from the solution. • Criteria based on those indicators are given to identify which initial guesses should be corrected in case of convergence failure of Newton's method • The criteria require the computation of the Jacobians and Hessians of the nonlinear equation residuals and are applicable to any system of equations. The initialization of equation-based differential-algebraic system models, and more in general the solution of many engineering and scientific problems, require the solution of systems of nonlinear equations. Newton-Raphson's method is widely used for this purpose; it is very efficient in the computation of the solution if the initial guess is close enough to it, but it can fail otherwise. In this paper, several criteria are introduced to analyze the influence of the initial guess on the evolution of Newton-Raphson's algorithm and to identify which initial guesses need to be improved in case of convergence failure. In particular, indicators based on first and second derivatives of the residual function are introduced, whose values allow to assess how much the initial guess of each variable can be responsible for the convergence failure. The use of such criteria, which are based on rigorously proven results, is successfully demonstrated in three exemplary test cases. [ABSTRACT FROM AUTHOR]

Deglutition syncope refers to an uncommon cause of neurally mediated syncope induced by swallowing. We briefly review a case of a 66-year-old man who experienced recurrent syncope episodes during ingestion of beverages, mainly water. Our investigations documented several short asymptomatic episodes of asystole and one prolonged complete atrioventricular block of around 15 seconds associated with the syncopal events, during swallowing. Barium x-ray and manometry evaluations revealed only a nonspecific esophageal dysmotility. An underlying sick-sinus syndrome was found on electrophysiologic study. A DDD pacemaker implantation was performed leading to total disappearance of patient's symptoms. [ABSTRACT FROM AUTHOR]

Equation-based modelling is a powerful approach to tame the complexity of large-scale simulation problems. Equation-based tools automatically translate models into imperative languages. When confronted with nowadays' problems, however, well assessed model translation techniques exhibit scalability issues that are particularly severe when models contain very large arrays. In fact, such models can be made very compact by enclosing equations into looping constructs, but reflecting the same compactness into the translated imperative code is nontrivial. In this paper, we face this issue by concentrating on a key step of equations-to-code translation, the equation/variable matching. We first show that an efficient translation of models with (large) arrays needs awareness of their presence, by defining a figure of merit to measure how much the looping constructs are preserved along the translation. We then show that the said figure of merit allows to define an optimal array-aware matching, and as our main result, that the so stated optimal array-aware matching problem is NP-complete. As an additional result, we propose a heuristic algorithm capable of performing array-aware matching in polynomial time. The proposed algorithm can be proficiently used by model translator developers in the implementation of efficient tools for large-scale system simulation. [ABSTRACT FROM AUTHOR]

The author expresses doubt on the conclusions by P. Schuetz et al in their review "Procalcitonin Algorithms for Antibiotic Therapy Decisions: A Systematic Review of Randomized Controlled Trials and Recommendations for Clinical Algorithms." He cites belief that meta-analysis is underpowered to provide evidence that pro-calcitonin (PCT) can affect mortality and inquires whether global adherence to the protocols can be a bias that affects the results of the meta-analysis.

Simple Summary: Peritoneal metastases (PMs), arising from gastric cancer (GC), are one of the most common patterns of synchronous and metachronous dissemination and are generally associated with a poor prognosis. New therapeutic modalities are being increasingly employed for such patients. Here, we provide an overview of the recent literature on this topic, along with two studies currently underway: one at Sapienza University of Rome and the other at the University of Verona, focusing on the use of neoadjuvant intraperitoneal chemotherapy in combination with a classical neoadjuvant systemic chemotherapy (SC). This overview emphasizes the results obtained using neoadjuvant intraperitoneal treatment, which may find a place not only in the Eastern world, where it now represents a standard of care, but also among Western practitioners. Gastric cancer (GC) continues to be one of the leading types of malignancies worldwide, despite an ongoing decrease in incidence. It is the fifth most frequent type of cancer in the world and the fourth leading cause of cancer death. Peritoneal metastases (PMs) occur in 20–30% of cases during the natural history of the disease. Systemic chemotherapy (SC) is undoubtedly the standard of care for patients with GC and PMs. However, with the development of highly effective regimens (SC combined with intraperitoneal chemotherapy), significant tumor shrinkage has been observed in many patients with synchronous GC and PMs, allowing some to undergo curative resection "conversion surgery" with long-term survival. In recent years, there has been growing interest in intraperitoneal chemotherapy for PMs, because the reduced drug clearance associated with the peritoneal/plasma barrier allows for direct and prolonged drug exposure with less systemic toxicity. These procedures, along with other methods used for peritoneal surface malignancies (PSMs), can be used in GCs with PMs as neoadjuvant chemotherapy or adjuvant treatments after radical surgery or as palliative treatments delivered either laparoscopically or—more recently—as pressurized intraperitoneal aerosol chemotherapy. The great heterogeneity of patients with stage IV gastric cancer did not allow us to carry out a systemic review; therefore, we limited ourselves to providing readers with an overview to clarify the indications and outcomes of integrated treatments for GCs with PMs by analyzing reports from the international clinical literature and the specific experiences of our oncoteam. [ABSTRACT FROM AUTHOR]

Simple Summary: In recent years, pressurized intraperitoneal aerosol chemotherapy (PIPAC) has emerged as a feasible method of intraperitoneal drug administration in patients affected by peritoneal cancer of primary or secondary origin. We performed a systematic review and meta-analysis with the aim of assessing the feasibility, safety, and efficacy of PIPAC. Background: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a novel intraperitoneal drug delivery method of low-dose chemotherapy as a pressurized aerosol in patients affected by peritoneal cancer of primary or secondary origin. We performed a systematic review and meta-analysis with the aim of assessing the feasibility, safety, and efficacy of PIPAC. Methods: A systematic literature search was performed using Medline and Web of Science databases from 1 January 2011, to inception, to 31 December 2021. Data were independently extracted by two authors. The Newcastle-Ottawa Scale was used to assess the quality and risk of bias of studies. Meta-analysis was performed for pathological response, radiological response, PCI variation along treatment, and for patients undergoing three or more PIPAC. Pooled analyses were performed using the Freeman–Tukey double arcsine transformation, and 95% CIs were calculated using Clopper–Pearson exact CIs in all instances. Results: A total of 414 papers on PIPAC were identified, and 53 studies considering 4719 PIPAC procedure in 1990 patients were included for analysis. The non-access rate or inability to perform PIPAC pooled rate was 4% of the procedures performed. The overall proportion of patients who completed 3 or more cycles of PIPAC was 39%. Severe toxicities considering CTCAE 3–4 were 4% (0% to 38.5%). In total, 50 studies evaluated deaths within the first 30 postoperative days. In the included 1936 patients were registered 26 deaths (1.3%). The pooled analysis of all the studies reporting a pathological response was 68% (95% CI 0.61–0.73), with an acceptable heterogeneity (I2 28.41%, p = 0.09). In total, 10 papers reported data regarding the radiological response, with high heterogeneity and a weighted means of 15% (0% to 77.8%). PCI variation along PIPAC cycles were reported in 14 studies. PCI diminished, increased, or remained stable in eight, one and five studies, respectively, with high heterogeneity at pooled analysis. Regarding survival, there was high heterogeneity. The 12-month estimated survival from first PIPAC for colorectal cancer, gastric cancer, gynecological cancer and hepatobiliary/pancreatic cancer were, respectively, 53%, 25%, 59% and 37%. Conclusions: PIPAC may be a useful treatment option for selected patients with PM, with acceptable grade 3 and 4 toxicity and promising survival benefit. Meta-analysis showed high heterogeneity of data among up-to-date available studies. In a subset analysis per primary tumor origin, pathological tumor regression was documented in 68% of the studies with acceptable heterogeneity. Pathological regression seems, therefore, a reliable outcome for PIPAC activity and a potential surrogate endpoint of treatment response. We recommend uniform selection criteria for patients entering a PIPAC program and highlight the urgent need to standardize items for PIPAC reports and datasets. [ABSTRACT FROM AUTHOR]

Simple Summary: Mini-invasive surgery represents an interesting yet challenging technical evolution for treating peritoneal metastases. This retrospective study aims to present the experience of the Italian Peritoneal Surface Malignancies Oncoteam with laparoscopic cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), including a detailed description of the technique and a systematic review of the literature. The study shows the feasibility and safety of laparoscopic CRS-HIPEC and its association with favorable outcomes in properly selected patients. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has gained increasing acceptance in clinical practice. Performing CRS and HIPEC laparoscopically represents a challenging and intriguing technical evolution. However, the experiences are limited, and the evidence is low. This retrospective analysis was performed on patients treated with laparoscopic CRS-HIPEC within the Italian Peritoneal Surface Malignancies Oncoteam. Clinical, perioperative, and follow-up data were extracted and collected on prospectively maintained databases. We added a systematic review according to the PRISMA method for English-language articles through April 2022 using the keywords laparoscopic, hyperthermic, HIPEC, and chemotherapy. From 2016 to 2022, fourteen patients were treated with Lap-CRS-HIPEC with curative intent within the Italian centers. No conversion to open was observed. The median duration of surgery was 487.5 min. The median Peritoneal Cancer Index (PCI) was 3, and complete cytoreduction was achieved in all patients. Two patients (14.3%) had major postoperative complications, one requiring reintervention. After a median follow-up of 16.9 months, eleven patients were alive without disease (78.6%), two patients developed recurrence (14.3%), and one patient died for unrelated causes (7.1%). The literature review confirmed these results. In conclusion, current evidence shows that Lap-CRS-HIPEC is feasible, safe, and associated with a favorable outcome in selected patients. An accurate patient selection will continue to be paramount in choosing this treatment. [ABSTRACT FROM AUTHOR]

The advent of portable equipment in the last years has brought ultrasound (US) technology available at patient bedside, giving the opportunity to non-cardiologists to extend cardiac assessment based on physical examination. Bedside echocardiography is a question-driven examination, where simple and often dichotomous answers are searched. It is performed using phased-array probes and bi-dimensional images are visually evaluated to obtain information regarding cardiac size and function, presence of pericardial effusion, gross valvular diseases. Although this approach cannot in any case substitute a standard 2D color-Doppler echocardiography, bedside echocardiography has been demonstrated to maintain a good diagnostic accuracy when limited to basic questions, even in the hands of short-trained non cardiologist physicians. At present the bedside US approach is widely used in different settings and focused echocardiography takes part together with US explorations of lung, abdomen and deep veins in an integrated perspective that perfectly fits with the holistic approach of the internist. In this context we address two typical scenarios encountered in the internal medicine divisions - the patient presenting with dyspnea or nonpost-traumatic hypotension - showing the main questions we can ask to bedside echocardiography for a rapid identification of the determinants of symptoms and consequently for a therapeutic choice based on more objective evidence. [ABSTRACT FROM AUTHOR]

Abstract: This article presents a methodology to help in the definition of the optimal design of power generation systems. The innovative element is the integration of requirements on dynamic performance into the system design procedure. Operational flexibility is an increasingly important specification of power systems for base- and part-load operation. Thus, it is crucial to discard, in an early phase of the design process, plant configurations which feature unacceptable dynamic performance. The test case is the preliminary design of an off-grid power plant serving an off-shore platform where one of the three gas turbines is combined with an organic Rankine cycle turbogenerator to increase the overall energy efficiency. The core of the procedure is a stationary model, capable of performing the on-design thermodynamic cycle calculation, and the design of the components of the system. The results of these simulations are used within the framework of a multi-objective optimization procedure to identify a number of equally optimal system configurations. A dynamic model of each of these systems is automatically parameterized, by inheriting its parameters values from the design model. Dynamic simulations allow then to discriminate among the initial set of solutions, thus providing the designs that also comply with dynamic requirements. [Copyright &y& Elsevier]

Background: The association between compliance to an enhanced recovery protocol (ERAS) and outcome after surgery for gastric cancer has been poorly investigated, particularly in Western patients. The aim of the study was to evaluate whether the rate of adherence to the ERAS program was correlated with outcome and time of discharge. Methods: A prospective, observational, multicenter study was designed to be performed at Italian referral centers for gastric surgery. The protocol was discussed and approved by the Italian Research Group on Gastric Cancer. Twenty-three ERAS domains were applied. A multivariate logistic regression was used to assess the association between ERAS compliance and overall and major complication rates. The Poisson regression model (measured as mean ratios) was used to assess the association of ERAS compliance rate and length of stay (LOS). Results: Eight centers participated and 290 subjects with a median age of 73 years were enrolled. The overall rates of adherence to pre-, intra-, and postoperative ERAS items were 69.8%, 60.3%, and 82.5%, respectively. At the multivariate model, there was an association between overall rate of morbidity and an overall ERAS compliance rate greater than 70% (OR 0.413; 95% CI 0.235–0.7240; P 0.002). A similar association was found for major complications (OR 0.328; 95% CI 0.151–0.709; P 0.005). The Poisson regression showed that in patients with ERAS compliance rate >70%, LOS was reduced of approximately 20% (mean ratio 0.812; 95% CI 0.694–0.950; P 0.009). Conclusions: These results suggest a moderate compliance to an ERAS program and a significant association between adherence and outcomes. [ABSTRACT FROM AUTHOR]

Introduction: Laparoscopy is used increasingly to treat malignant and benign colorectal surgical diseases. However, this practice is still not offered to all patients. Many barriers halt the widespread use of laparoscopic colorectal surgery. Both surgeon's and patient's factors contribute to limit a wider use of laparoscopy in colorectal surgery.Materials and Methods: We retrospectively analyzed 408 consecutive colorectal resections in a 4-year period, to find out if a selection bias exists in using laparotomy or laparoscopy for colorectal surgical diseases, and which factors are associated with a poor use of laparoscopy or to a preferred laparotomy.Results: In our practice, advanced disease, American Society of Anesthesiologist class III and IV, and emergency status are all patient-related factors associated with laparotomy. Surgeon's age more than 52 years and lack of laparoscopic training are surgeon-related factors that negatively affect the chance of being operated on with the laparoscopic technique.Conclusions: An extensive laparoscopic colorectal training and a supporting environment, especially during the night shift, are needed to facilitate the use of laparoscopy in colorectal surgery avoiding a bias in selecting surgical candidates to one technique or another. [ABSTRACT FROM AUTHOR]

An experimental research was managed in the framework of the PASSAM European Project to measure the efficiency of high-pressure sprays in capturing aerosols when applied to a filtered containment venting system in case of severe accident. The campaign was carried out in a purposely built facility composed by a scrubbing chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls to permit the complete view of the aerosol removal process, where the aerosol was injected to form a cloud of specific particle concentration. The chamber was equipped with a high pressure water spray system with a single nozzle placed on its top. The test matrix consisted in the combination of water pressure injections, in the range 50–130 bar, on a cloud of monodispersed SiO 2 particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m 3 . The spray was kept running for 2 min and the efficiency of the removal was evaluated, along the test time, using an optical particle sizer. With respect to low-pressure sprays, the removal efficiency turned out much more significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure spray system. The highest removal rate was detected with 1 μm particles at the highest water injection pressure, mainly because of the high concentration of droplets with high velocity, while lower removal was measured for 0.5 μm particles. No influence of the initial aerosol concentration was observed for both particle sizes. [ABSTRACT FROM AUTHOR]

Osteoporosis (OP) is a silent disease unless a fracture occurs; it is a major health problem, mainly due to fragility fractures, that occur at vertebral and peripheral sites. Vertebral fractures (VF) are probably the most common fragility fractures, but they go often unrecognized. The main clinical symptoms of VF are acute and chronic back pain, spinal deformity, reduced mobility and impaired quality of life. They are frequently associated with other fragility fractures. We examined 478 patients at our outpatient clinic, who were referred for fragility fracture occurrence. The most common fragility fractures was hip fractures. However, after execution of spine X-rays in patients who had sustained hip fracture, we found that a large proportion of them had VF, which had not been reported in their medical history. [ABSTRACT FROM AUTHOR]

Osteonecrosis of the femoral head is a destructive disease that usually affects young adults with high functional demands and can have devastating effects on hip joint. The treatment depends on extent and location of the necrosis lesion and on patient's factors, that suggest disease progression, collapse probability and also implants survival. Non-idiopathic osteonecrosis patients had the worst outcome. There is not a gold standard treatment and frequently it is necessary a multidisciplinary approach. Preservation procedures of the femoral head are the first choice and can be attempted in younger patients without head collapse. Replacement procedure remains the main treatment after failure of preserving procedures and in the late-stage ONFH, involving collapse of the femoral head and degenerative changes to the acetabulum. Resurfacing procedure still has good results but the patient selection is a critical factor. Total hip arthroplasties had historically poor results in patients with osteonecrosis. More recently, reports have shown excellent results, but implant longevity and following revisions are still outstanding problems. [ABSTRACT FROM AUTHOR]

A blow-down wind tunnel for real-gas applications has been designed, validated by means of dynamic simulation, and then built. The facility is aimed at characterizing an organic vapor stream, representative of the expansion taking place in organic Rankine cycle (ORC) turbines, by independent measurements of pressure, temperature, and velocity. The characterization of such flows and the validation of design tools with experimental data, which are still lacking in the scientific literature, is expected to strongly benefit the performance of future ORC turbines. The investigation of flow fields within industrial ORC turbines has been strongly limited by the unavailability of calibration tunnels for real-gas operating probes, by the limited availability of plants, and by restricted access for instrumentation. As a consequence, it has been decided to design and realize a dedicated facility, in partnership with a major" ORC manufacturer. The paper thoroughly discusses the design and the dynamic simulation of the apparatus, presents its final layout, and shows the facility "as built". A straight-axis planar convergent-divergent nozzle represents the test section for early tests, but the test rig can also accommodate linear blade cascades. The facility implements a blow down operating scheme, due to high fluid density and operating temperature, which prevent continuous operation because of the prohibitive thermal power required. A wide variety of working fluids can be tested, with adjustable operating conditions up to maximum temperature and pressure of 400 °C and 50 bar, respectively. Despite the fact that the test rig operation is unsteady, the inlet nozzle pressure can be kept constant by a control valve. In order to estimate the duration of the setup and experimental phase, and to describe the time evolution of the main process variables, the dynamic plant operation, including the control system, has been simulated. Design and simulation have been performed with both lumped-parameter and ID models, using siloxane MDM and hydrofluorocarbon R245fa as the reference working fluids, described by state-of-the-art thermodynamic models. Calculations show how experiments may last from 12 seconds up to several minutes (depending on the fluid and test pressure), while reaching the experimental conditions requires few hours, consistently with the performance of daily-based experiments. Moreover, the economic constraints have been met by the technical solutions adopted for the plant, allowing the construction of the facility. [ABSTRACT FROM AUTHOR]

Abstract: Inability to maintain the upright position is manifested by a number of symptoms shared by either human pathophysiology and conditions following weightlessness or bed rest. Alterations of the neural sympathetic cardiovascular control have been suggested to be one of the potential underlying etiopathogenetic mechanisms in these conditions. We hypothesize that the study of the autonomic profile of human orthostatic intolerance syndromes may furnish a valuable insight into the complexity of the sympathetic alterations leading to a reduced gravitational tolerance. In the present paper we describe abnormalities both in the magnitude and in the pattern of the sympathetic neural firing observed in patients affected by orthostatic intolerance, attending the upright position. Also, we discuss similarity and differences in the neural sympathetic mechanisms regulating the cardiovascular system during the gravitational stimulus both in clinical syndromes and in subjects returning from space. [Copyright &y& Elsevier]

Background: Syncope is a clinical event characterized by a transient loss of consciousness, estimated to affect 6.2/1000 person-years, resulting in remarkable health care and social costs. Human pathophysiology suggests that heat may promote syncope during standing. We tested the hypothesis that the increase of air temperatures from January to July would be accompanied by an increased rate of syncope resulting in a higher frequency of Emergency Department (ED) visits. We also evaluated the role of maximal temperature variability in affecting ED visits for syncope. Methodology/Principal Findings: We included 770 of 2775 consecutive subjects who were seen for syncope at four EDs between January and July 2004. This period was subdivided into three epochs of similar length: 23 January-31 March, 1 April-31 May and 1 June-31 July. Spectral techniques were used to analyze oscillatory components of day by day maximal temperature and syncope variability and assess their linear relationship. There was no correlation between daily maximum temperatures and number of syncope. ED visits for syncope were lower in June and July when maximal temperature variability declined although the maximal temperatures themselves were higher. Frequency analysis of day by day maximal temperature variability showed a major non-random fluctuation characterized by a ∼23-day period and two minor oscillations with ∼3- and ∼7-day periods. This latter oscillation was correlated with a similar ∼7-day fluctuation in ED visits for syncope. Conclusions/Significance: We conclude that ED visits for syncope were not predicted by daily maximal temperature but were associated with increased temperature variability. A ∼7-day rhythm characterized both maximal temperatures and ED visits for syncope variability suggesting that climate changes may have a significant effect on the mode of syncope occurrence. [ABSTRACT FROM AUTHOR]

This study was designed to analyze the prognostic significance of the staging system based on the ratio of metastatic lymph nodes (TRM) compared with the TNM staging system in patients with gastric cancer. We reviewed the data of 219 patients who underwent gastrectomy for node-positive M0 cancer. Node Ratio (NR) categories (NR1: 1–15%; NR2: 16–40%; NR3: >40%) were determined by the best cutoff approach at log-rank test. After confirming the prognostic validity of NR in a collinearity-free Cox regression analysis, among different combinations of pT and NR categories we selected five prognostically homogeneous TRM classes. To compare the prognostic power of the TRM vs. TNM systems, we plotted TRM and TNM classes against the mortality estimates. Both of the TRM and TNM classifications significantly stratified patients outcomes ( p < 0.0001), but the TRM system identified prognostic subgroups more homogeneous than the TNM system. The TRM staging system is a simple and reliable tool to stratify patients with gastric cancer and has a higher prognostic power than the current system. [ABSTRACT FROM AUTHOR]

Abdominal aortic aneurysm (AAA) is a focal dilatation of the aorta, caused by both genetic and environmental factors. Although vascular endothelium plays a key role in AAA progression, the biological mechanisms underlying the mechanical stress involvement are only partially understood. In this study, we developed an in vitro model to characterize the role of mechanical stress as a potential trigger of endothelial deregulation in terms of inflammatory response bridging between endothelial cells (ECs), inflammatory cells, and matrix remodeling. In AAA patients, data revealed different degrees of calcification, inversely correlated with wall stretching and also with inflammation and extracellular matrix degradation. In order to study the role of mechanical stimulation, endothelial cell line (EA.hy926) has been cultured in healthy (10% strain) and pathological (5% strain) dynamic conditions using a bioreactor. In presence of tumor necrosis factor alpha (TNF-α), high levels of matrix metalloproteinase-9 (MMP-9) expression and inflammation are obtained, while mechanical stimulation significantly counteracts the TNF-α effects. Moreover, physiological deformation also plays a significant role in the control of the oxidative stress. Overall our findings indicate that, due to wall calcification, in AAA there is a significant change in terms of decreased wall stretching. [ABSTRACT FROM AUTHOR]