Is simulation the only keystone of surgical training?

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A Dirichlet process model for change‐point detection with multivariate bioclimatic data

Motivated by real-world data of monthly values of precipitation, minimum, and maximum temperature recorded at 360 monitoring stations covering the Italian territory for 60 years (12 × 60 months), in this work we propose a change-point model for multiple multivariate time series, inspired by the hierarchical Dirichlet process. We assume that each station has its change-point structure and, as main novelties, we allow unknown subsets of the parameters in the data likelihood to stay unchanged before and after a change-point, that stations possibly share values of the same parameters and that the unknown number of weather regimes is estimated as a random quantity. Owing to the richness of the formalization, our proposal enables us to identify clusters of spatial units for each parameter, evaluate which parameters are more likely to change simultaneously, and distinguish between abrupt changes and smooth ones. The proposed model provides useful benchmarks to focus monitoring programs regarding ecosystem responses. Results are shown for the whole data, and a detailed description is given for three monitoring stations. Evidence of local behaviors includes highlighting differences in the potential vulnerability to climate change of the Mediterranean ecosystems from the Temperate ones and locating change trends distinguishing between continental plains and mountain ranges

Optical response of strongly absorbing inhomogeneous materials: Application to paper degradation

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Experimental and theoretical study of the yellowing of ancient paper

Paper is the most widely used writing support due to the remarkable properties of its principal component - cellulose - one of the most abundant biomaterials present on Earth. However, due to the complexity of the material, an exhaustive picture of its degradation pathways is still missing. In this paper, we will present recent results and progresses obtained in the comprehension of the role of cellulose oxidation in the yellowing of ancient paper. Visible and ultraviolet spectra of cellulose in ancient paper samples and reference modern samples artificially aged have been interpreted with the aid of ab-initio Time-Dependent Density Functional Theory calculations. Through the comparison of measured and calculated absorption spectra, several oxidized forms of cellulose polymers, acting as chromophores, and responsible for ancient paper yellowing were identified. The relative concentration of ketones and aldehydic groups depends on the environmental conditions in which samples were stored along their life

Ultrasound-guided erector spinae plane block versus intercostal nerve block for post-minithoracotomy acute pain management: a randomized controlled trial

Objective: Several nerve block procedures are available for post-thoracotomy pain management.Design: In this randomized trial, the authors aimed to determine whether the analgesic effect of preoperative ultrasound-guided erector spinae plane block (ESPB) might be superior to that of intraoperative intercostal nerve block (ICNB) in pain control in patients undergoing minithoracotomy.Setting: University hospital.Participants: Sixty consecutive adult patients scheduled to undergo minithoracotomy for lung resection were enrolled.Interventions: Patients were allocated randomly in a 1:1 ratio to receive either single-shot ESPB or ICNB.Measurements and Main Results: The primary outcome was the intensity of postoperative pain at rest, assessed with the numeric rating scale (NRS). The secondary outcomes were (1) dynamic NRS values (during cough); (2) perioperative analgesic requirements; (3) patient satisfaction, on the basis of a verbal scale (Likert scale); and (4) respiratory muscle strength, considering the maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) variation from baseline. The ESPB group showed lower postoperative static and dynamic NRS values than the ICNB group (p < 0.05). Total remifentanil consumption and requirements for additional analgesics were lower in the ESPB group (p < 0.05). Patient satisfaction was higher in the ESPB group (p < 0.001). A significant overall time effect was found in MIP and MEP variation (p < 0.001); ESPB values were higher at all points, reaching a statistically significant level at the first and sixth hours for MIP, and at the first, 12th, 24th, and 48th hours for MEP (p < 0.05).Conclusions: ESPB was demonstrated to provide superior analgesia, lower perioperative analgesic requirements, better patient satisfaction, and less respiratory muscle strength impairment than ICNB in patients undergoing minithoracotomy. (C) 2020 Elsevier Inc. All rights reserved

Quantitative diagnostics of ancient paper using THz time-domain spectroscopy

In this work we have studied the terahertz spectra of modern artificially aged and ancient paper samples using terahertz time-domain spectroscopy. Hydrothermal artificial ageing was performed in closed and open reactors. Ancient paper samples were produced during the 15th century in European countries. The main aim of the work is the quantitative assessment of spectral feature observed by terahertz spectroscopy as a function of degradation. To this goal, the state of degradation of paper samples was characterized by crystallinity measurements obtained by using X-ray diffraction and by the degree of polymerization of cellulose polymers obtained by size exclusion chromatography. The behavior of the terahertz spectra was formerly investigated as a function of the hydration of paper samples. This allowed discriminating between the spectral features induced by the presence of water and those induced by degradation of paper. Results indicate clear dependences of spectral parameters from the evolution of crystallinity and the degree of polymerization. They can be used as a nondestructive analytical method to assess the state of degradation of ancient paper by terahertz spectroscopy

Timing of surgery following SARS‐CoV‐2 infection: an international prospective cohort study

Peri-operative SARS-CoV-2 infection increases postoperative mortality. The aim of this study was to determine the optimal duration of planned delay before surgery in patients who have had SARS-CoV-2 infection. This international, multicentre, prospective cohort study included patients undergoing elective or emergency surgery during October 2020. Surgical patients with pre-operative SARS-CoV-2 infection were compared with those without previous SARS-CoV-2 infection. The primary outcome measure was 30-day postoperative mortality. Logistic regression models were used to calculate adjusted 30-day mortality rates stratified by time from diagnosis of SARS-CoV-2 infection to surgery. Among 140,231 patients (116 countries), 3127 patients (2.2%) had a pre-operative SARS-CoV-2 diagnosis. Adjusted 30-day mortality in patients without SARS-CoV-2 infection was 1.5% (95%CI 1.4–1.5). In patients with a pre-operative SARS-CoV-2 diagnosis, mortality was increased in patients having surgery within 0–2 weeks, 3–4 weeks and 5–6 weeks of the diagnosis (odds ratio (95%CI) 4.1% (3.3–4.8), 3.9% (2.6–5.1) and 3.6% (2.0–5.2), respectively). Surgery performed ≥ 7 weeks after SARS-CoV-2 diagnosis was associated with a similar mortality risk to baseline (odds ratio (95%CI) 1.5% (0.9– 2.1%)). After a ≥ 7 week delay in undertaking surgery following SARS-CoV-2 infection, patients with ongoing symptoms had a higher mortality than patients whose symptoms had resolved or who had been asymptomatic (6.0% (95%CI 3.2–8.7) vs. 2.4% (95%CI 1.4–3.4) vs. 1.3% (95%CI 0.6–2.0%), respectively). Where possible, surgery should be delayed for at least 7 weeks following SARS-CoV-2 infection. Patients with ongoing symptoms ≥ 7 weeks from diagnosis may benefit from further delay

Association of kidney disease measures with risk of renal function worsening in patients with type 1 diabetes

Background: Albuminuria has been classically considered a marker of kidney damage progression in diabetic patients and it is routinely assessed to monitor kidney function. However, the role of a mild GFR reduction on the development of stage 653 CKD has been less explored in type 1 diabetes mellitus (T1DM) patients. Aim of the present study was to evaluate the prognostic role of kidney disease measures, namely albuminuria and reduced GFR, on the development of stage 653 CKD in a large cohort of patients affected by T1DM. Methods: A total of 4284 patients affected by T1DM followed-up at 76 diabetes centers participating to the Italian Association of Clinical Diabetologists (Associazione Medici Diabetologi, AMD) initiative constitutes the study population. Urinary albumin excretion (ACR) and estimated GFR (eGFR) were retrieved and analyzed. The incidence of stage 653 CKD (eGFR < 60 mL/min/1.73 m2) or eGFR reduction > 30% from baseline was evaluated. Results: The mean estimated GFR was 98 \ub1 17 mL/min/1.73m2 and the proportion of patients with albuminuria was 15.3% (n = 654) at baseline. About 8% (n = 337) of patients developed one of the two renal endpoints during the 4-year follow-up period. Age, albuminuria (micro or macro) and baseline eGFR < 90 ml/min/m2 were independent risk factors for stage 653 CKD and renal function worsening. When compared to patients with eGFR > 90 ml/min/1.73m2 and normoalbuminuria, those with albuminuria at baseline had a 1.69 greater risk of reaching stage 3 CKD, while patients with mild eGFR reduction (i.e. eGFR between 90 and 60 mL/min/1.73 m2) show a 3.81 greater risk that rose to 8.24 for those patients with albuminuria and mild eGFR reduction at baseline. Conclusions: Albuminuria and eGFR reduction represent independent risk factors for incident stage 653 CKD in T1DM patients. The simultaneous occurrence of reduced eGFR and albuminuria have a synergistic effect on renal function worsening