Acid-Base Disorders in Patients with Chronic Obstructive Pulmonary Disease: A Pathophysiological Review

The authors describe the pathophysiological mechanisms leading to development of acidosis in patients with chronic obstructive pulmonary disease and its deleterious effects on outcome and mortality rate. Renal compensatory adjustments consequent to acidosis are also described in detail with emphasis on differences between acute and chronic respiratory acidosis. Mixed acid-base disturbances due to comorbidity and side effects of some drugs in these patients are also examined, and practical considerations for a correct diagnosis are provided

Modelling of 3-Phase p-q Theory-Based Dynamic Load for Real-Time Simulation

This article proposes a new method of modelling dynamic loads based on instantaneous p-q theory, to be employed in large powers system network simulations in a digital real-time environment. Due to the use of computationally heavy blocks such as phase-locked-loop (PLL), mean calculation,and coordinate transformation blocks (e.g., abc–dq0), real-time simulation of large networks with dynamic loads can be challenging. In order to decrease the computational burden associated to the dynamic load modelling, a p-q theory-based approach for load modelling is proposed in this paper. This approach is based on the well-known p-q instantaneous theory developed for power electronics converters, and it consists only of linear controllers and of a minimal usage of control loops, reducing the required computational power. This improves real-time performance and allows larger scale simulations. The introduced p-q theory-based load (PQL) model has been tested on standard networks implemented in a digital real time simulator, such as the SimBench semi-urban medium voltage network and the 118-bus Distribution System, showing significant improvement in terms of computational capability with respect to standard load models (e.g., MATLAB/Simulink dynamic load)

METHODOLOGICAL FRAMEWORK TO IMPROVE PPP PROJECTS

The Public–Private Partnership (PPP) plays a significant role in the construction industry. It is of special importance because of its weight in the global economy and the lack of funding for major projects. The PPP concept, as a procurement strategy, is successful only if the major stakeholders, namely the public sector, private consortium, and end–users are all satisfied with project outcomes. There have been reported cases of problems associated with the initial stages of the PPP process in terms of bidding costs and anticipated costs of construction and operation. The banks’ attention is currently centered on the promotors’ financial stability rather than on project quality. The key issue is to improve the efficiency for the whole building lifecycle. In this context, BIMM philosophy (not just Building Information Modeling but also Information Management) may be a powerful tool. In other words, is there room to put this concept in practice without jeopardizing service quality, innovation and efficiency? The answer to this question is explored in this paper. The use of Technical Sheets for PPP procurement like policy models may enhance systematic and integrated management of the whole building process. This technical framework allows one to collect project data, grouped into three areas: design, construction, and operation. In so doing, a Public Agency may assess project quality

Analysis of Flat Plate Honeycomb Seals Aerodynamic Losses: Effects of Clearance☆

Abstract Among the various type of seals used in gas turbine secondary air system to guarantee sufficient confinement of the main gas path, honeycomb seals well perform in terms of enhanced stability and reduced leakage flow. Reliable estimates of the sealing performance of honeycomb packs employed in industrial gas and steam turbines, are however missing in literature, thus, in order to evaluate the complete characteristic curve of the seals in the wide range of working conditions, an experimental campaign was planned. This work reports the findings of an experimental campaign aimed at evaluating aerodynamic losses within honeycomb seals. Due to the generally large amount of honeycomb cells typically present in real seals, it would be convenient to treat the sealing effect of the honeycomb pack as an increased distributed friction factor on the plain top surface that is why the simplest config- uration, the honeycomb facing a flat plate, is employed in this paper. The geometry of the hexagonal cell and the investigated clearances were chosen to well represent actual honeycomb packs employed in industrial compressors. First the pressure distribu- tion within the seal was analysed verifying that downstream the first 5 rows of cells, where entrance effects are predominant, the relative pressure drop is almost constant thus the use of an equivalent friction factor is appropriate to characterize the seal. Subse- quent analysis focused on the characterization of the friction factor as function of the Reynolds number with the aim of establishing the proper geometrical scaling to achieve flow conditions similar to real turbine most critical ones. The different behaviour of the honeycomb sealing depending on the hexagonal cell arrangement and dimensions was evaluated in terms of friction factor. Comparison with results coming from a previous CFD investigation is also presented and discussed in this paper

Mandibular advancement devices vs nasal-continuous positive airway pressure in the treatment of obstructive sleep apnoea. Systematic review and meta-analysis

Obstructive sleep apnoea (OSA) is a common disorder that may affect at least 2 to 4% of the adult population. Nasal-Continuous Positive Airway Pressure (N-CPAP) is today considered the gold standard for the treatment of OSA. The development of oral appliances (OAs) represents a new approach for the management of this pathology. The aim of this systematic review is to compare the efficacy of OAs and N-CPAP in the treatment of patients with mild to severe OSA. A PubMed-MEDLINE and Cochrane databases search of articles published between 1982 and 2016 comparing the effect of N-CPAP and OAs in OSA patients was conducted during July 2016. The studies were selected and stratified according to PRISMA and SORT criteria. The main outcome measure was post-treatment Apnoea-Hypopnoea Index (AHI) while secondary outcomes included post-treatment Epworth Score Scale (ESS) score and lowest Oxygen Saturation level. N-CPAP was significantly more effective in suppressing AHI than OA. Moreover, N- CPAP was significantly more effective in increasing post-treatment lowest Oxygen Saturation level than OA. However, no significant different in decreasing ESS values was found between the two treatments. On the basis of evidence in this review it would appear appropriate to offer OA therapy to those who are unwilling or unable to persist with CPAP therapy. N-CPAP still must be considered the gold standard treatment for OSA and, therefore, OAs may be included in the list of alternative options

Necrotizing Panniculitis as an Uncommon Manifestation of Acute Pancreatitis

Pancreatic panniculitis is a rare disorder affecting 2–3% of patients with pancreatic disease. The findings are characterized by tender, erythematous, subcutaneous nodules which may undergo spontaneous ulceration with discharge of brownish and viscous material derived from colliquative necrosis of adipocytes. The lesions are usually localized in the lower limbs, although they may also extend to the buttocks and also involve the trunk, upper limbs and scalp. They can precede overt pancreatic disease in 40% of cases. The typical histological features observed in these lesions are characterized by necrotic adipocytes with absent nuclei (better known as ‘ghost cells’) in the context of a predominantly lobular panniculitis. We describe the case of a 78-year-old cirrhotic woman admitted to our department with abdominal pain affecting the upper abdomen and a 3-day fever. On physical examination, multiple tender erythematous nodules, with irregular margins, were present on the pretibial regions of both lower legs, ranging in size from 0.8 to 1.5 cm. Pancreatic amylase and lipase were elevated and abdominal computed tomography revealed acute pancreatitis with oedema, focal gland enlargement of the pancreatic tail and perivisceral inflammation. Histological examination of the lesions was consistent with a diagnosis of necrotizing granulomatous panniculitis

Effusion Cooling Plates for Combustor Liners: Experimental and Numerical Investigations on the Effect of Density Ratio

AbstractEffusion cooling represents the state-of-the-art of liner cooling technology for modern combustors. The present paper describes experimental tests aiming at evaluating the cooling performance of a multi-perforated plate in real engine representative fluid- dynamic conditions. Adiabatic effectiveness maps were obtained following the mass transfer analogy by the use of Pressure Sensitive Paint. In addition, a CFD campaign was performed in order to benchmark the reliability in estimating the cooling performance of effusion cooling liners. In order to include anisotropic diffusion effects, the k − ω SST turbulence model was corrected considering a tensorial definition of the eddy viscosity with an algebraic correction to dope its stream-span components

TERT Promoter Mutations in Papillary Thyroid Microcarcinomas

Small papillary thyroid carcinomas have contributed to the worldwide increased incidence of differentiated thyroid cancer observed over the past decades. However, the mortality rate has not changed over the same period of time, raising questions about the possibility that thyroid cancer patients, especially those with small tumors, are overdiagnosed and overtreated. Molecular prognostic marker able to discriminate aggressive thyroid cancers from those with an indolent course would be of great relevance to tailor the therapeutic approach and reduce overtreatment. Mutations in the TERT promoter were recently reported to correlate strongly with aggressiveness in advanced forms of thyroid cancer, holding promise for a possible clinical application. The occurrence and potential clinical relevance of TERT mutations in papillary thyroid microcarcinomas (mPTCs) is currently unknown. This study aimed to analyze the occurrence of two TERT promoter mutations (-124C>T and -146C>T) and their potential association with unfavorable clinical features in a large cohort of mPTCs