Estimation accuracy vs. engineering significance of contact parameters for solid dampers

Abstract All numerical models of friction-damped bladed arrays require knowledge or information of contact-friction parameters. In the literature, these parameters are typically tuned so that the experimental Frequency Response Function (FRF) of a damped blade matches its numerical counterpart. It is well known that there exist multiple combinations of contact parameters capable of satisfying a given experimental-numerical FRF match. A better approach towards a finer tuning could be based on directly measuring contact forces transmitted between blade platforms through the damper: in this case friction coefficients are estimated through tangential over normal force components during those hysteresis segments which are safely identified as being in a slip condition. This has been applied by these authors to rigid bar (solid) dampers. Unfortunately, the four contact stiffness values (left and right damper-platform contact, normal and tangential) are more than the measurements available in the technique presented by these authors. Therefore, the problem is underdetermined. The purpose of this paper is twofold, i.e., to propose an alternative way to estimate contact stiffness values (i.e. thus solving the under-determinacy mentioned above) and to check the effective significance of such estimates from a practical engineering point of view. The contact parameter estimation technique proposed by these authors produces, for each contact parameter, a best-fit value and an uncertainty band. It will be shown that the uncertainty affecting each contact parameter results in an uncertainty on the equivalent damping and stiffness indicators at blade level which is lower than 5%

Constraining the origin of UHECRs and astrophysical neutrinos

We explore the possibility of a common origin of ultrahigh energy cosmic rays (UHECRs) and astrophysical neutrinos and further constrain sources which are consistent with this possibility. We show that the common origin hypothesis can be satisfied for the Sibyll2.3c hadronic interaction model but is difficult to accommodate for EPOS-LHC, showing that multimessenger analyses have the power to also constrain hadronic physics beyond LHC energies. We constrain properties of UHECR source environments (and potentially astrophysical neutrino sources), including their photon temperature, gas density, size, magnetic field strength and coherence length, using UHECR and neutrino spectra and composition. Our analysis represents a new type of information on UHECR sources, independent of the mechanism responsible for the UHECR acceleration

Infodemiological patterns in searching medication errors: Relationship with risk management and shift work

INTRODUCTION: Western world health care systems have been trying to improve their efficiency and effectiveness in order to respond properly to population aging and non-communicable diseases epidemic. Treatment of the elderly population is becoming complex due to the high number of prescribed drugs because of multimorbidity. Errors in drugs administration in different health care related settings are an actual important issue due to different causes. Aim of this observational study is to measure the online interest in seeking medication errors information related to risk management and shift work. MATERIALS AND METHODS: We investigated Google Trends® for popular search relating to medication errors, risk management and shift work. Relative search volumes (RSVs) were evaluated from 2008 to 2018. A comparison between RSV curves related to medication errors, risk management and shift work was carried out. Then, we compared the world to Italian search. RESULTS: RSVs were persistently higher for risk management than for medication errors (mean RSVs 069 vs. 48%) and RSVs were stably higher for medication errors than shift work (mean RSVs 48 vs. 22%). In Italy, RSVs were much lower compared to the rest of the world, and RSVs for medication errors during the study period were negligible. Mean RSVs for risk management and shift work were 3 and 25%, respectively. RSVs related to medication errors and clinical risk management were correlated (r=0.520, p<0.0001). CONCLUSIONS: Google Trends® search query volumes related to medication errors, risk management and shift work are different. RSVs for risk management are higher, and they are correlated with medication errors. Also, shift work search appears to be lower. These results should be interpreted in order to correctly evaluate how to decrease the number of medication errors in different health care related setting

Lo studio FAST: FAringotonsillite STreptococcica in età pediatrica Impatto farmacoeconomico delle Linee Guida dell'American Academy of Pediatrics sulla pratica clinica di 600 pediatri italiani

The American Academy of Pediatrics (AAP) has recently published its new guidelines for the treatment of pediatric tonsillopharyngitis; a diagnostic test for the detection of streptococci is recommended, followed by a treatment with penicillins (10 days) or cephalosporins (5 days) in case of positivity, and by no treatment otherwise. The success of a guideline, in general, depends on its diffusion in practice and on its adaptability to different local settings. The aim of the present study (FAST) was the evaluation of the clinical and economical impact of the application of the AAP guidelines in the Italian reality. The study was conducted with the cooperation of 600 pediatricians, uniformly distributed on the Italian territory, and involved 3072 patients. The pediatricians were left free to decide whether to follow the guidelines or not. The results of the analysis indicate that only some 20% of the pediatricians adhered to the suggested protocol; the total cost (calculated in the perspective of the National Health System, with a time horizon of about 3 months) per patient, nonetheless, resulted inferior in the group treated according to the proposed protocol (50,45 • vs. 53,30 •). Furthermore, a lower incidence of complications occurred in these patients. Among the "off-protocol" behaviors, two showed particularly evident misuse of health resources: inappropriate treatment after test positivity (59,15 •/patient), and treatment after test negativity (14% of the total population). Another interesting, although not surprising, result of this study was the evidence that penicillins are as effective as cephalosporins in the short-term, but significantly inferior in terms of complications, positivity for streptococci at the control test, and complications detected at follow-up

Paraneoplastic Acanthosis Nigricans Maligna

Acanthosis Nigricans Maligna (ANM) is a paraneoplastic syndrome, defined as a condition that arises in association with a malignancy elsewhere in the body but without malignant nature per se. It’s a rare dermatopathy that occurs in men and women over age 40, without racial predilection or known familial association. Clinically, ANM showed symmetric,hyperpigmented plaques with variable amounts of epidermal hypertrophy, ranging in color from yellow to brown or black, often with overlaid papillomas. The most common affected sites are body flexures and the posterior neck, but also mucosal surface involvement is frequent and may be the only clinical symptom present. Any mucosal surface can be involved, and as regards the oral cavity, disease affects the lips, tongue, palate, buccal and gingival mucosa.ANM is primarily associated with adenocarcinomas, mostly of gastric origin. Accordingly, the progression of the tumor will lead to a worsening of the ANM, while regress in case of tumour treatment, and resurface with recurrence and metastases. A 62-year-old man was referred for evaluation of papillomatous lesions of the oral mucosa, appeared in previous months. The patient was diagnosed a gastric adenocarcinoma at an advanced stage 6 months before. Clinical examination showed diffuse papillomatous or wart-like areas of normal mucosal color and soft consistency involving lips,oral mucosa and hard palate. The tongue and the vestibular mucosa were thickened and furrowed. The lesions are asymptomatic. A biopsy was performed, and histopathological analysis revealed acanthosis and papillomatosis, hyperkeratosis,and lymphohistiocytic infiltrate. The patient was clinically diagnosed with ANM, according to clinical and histologic findings, and the patient’s medical history. Isotretinoin 0,05% was prescribed for local therapy. The patient did not return to follow-up due to complications of gastric adenocarcinoma, and died 6 months late

Dietary fiber and gut microbiota in renal diets

Nutrition is crucial for the management of patients affected by chronic kidney disease (CKD) to slow down disease progression and to correct symptoms. The mainstay of the nutritional approach to renal patients is protein restriction coupled with adequate energy supply to prevent malnutrition. However, other aspects of renal diets, including fiber content, can be beneficial. This paper summarizes the latest literature on the role of different types of dietary fiber in CKD, with special attention to gut microbiota and the potential protective role of renal diets. Fibers have been identified based on aqueous solubility, but other features, such as viscosity, fermentability, and bulking effect in the colon should be considered. A proper amount of fiber should be recommended not only in the general population but also in CKD patients, to achieve an adequate composition and metabolism of gut microbiota and to reduce the risks connected with obesity, diabetes, and dyslipidemia

Possible link between Hashimoto's thyroiditis and oral lichen planus: a novel association found

none5Lo Muzio L.; Santarelli A.; Campisi G.; Lacaita MG.; Favia G.Lo Muzio, L.; Santarelli, Andrea; Campisi, G.; Lacaita, M. G.; Favia, G