Consolidation of a collar truss with a steel cable system

Post-tensioning techniques for strengthening existing timber elements have been used throughout history with excellent results. Former applications on wooden trusses have already shown some of the advantages of such a consolidating system, but very few tests were performed on the topic. During an experimental campaign, a full-scale historical timber truss was deeply analysed and tested in its original (unreinforced) condition, reaching a considerable level of damage. It was later repaired with a steel cable system, using prestresses to recover the structure bearing capacity, and tested again. The results show that the repair allowed a recovery of at least the 80% of the ultimate load-carrying capacity. The complete failure was not achieved, but it is likely to be presumed that the structure could have regained the totality of its strength. The data acquired in both tests were later compared in order to understand in detail the behavior of the truss.The present work was made within a Master thesis of the Erasmus Mundus Advanced Masters course in Structural Analysis of Monuments and Historical Constructions. The authors acknowledge also the support and assistance of Augusto de Oliveira Ferreira e Companhia Lda (AOF)

Human protein C concentrates in adult septic patients

Some case reports and case series suggest that protein C concentrates may improve the outcome in patients with congenital or acquired protein C deficiency (not only in those with sepsis induced purpura fulminans). We reviewed the published literature on the use of protein C concentrates in adult septic patients and found that it is limited to less than 70 patients reported in observational studies with a 70% survival, and added our personal experience (two adult patients with sepsis and contraindications to recombinant activated protein C)

Continuous vs Intermittent Meropenem Administration in Critically Ill Patients With Sepsis

Importance: Meropenem is a widely prescribed β-lactam antibiotic. Meropenem exhibits maximum pharmacodynamic efficacy when given by continuous infusion to deliver constant drug levels above the minimal inhibitory concentration. Compared with intermittent administration, continuous administration of meropenem may improve clinical outcomes. Objective: To determine whether continuous administration of meropenem reduces a composite of mortality and emergence of pandrug-resistant or extensively drug-resistant bacteria compared with intermittent administration in critically ill patients with sepsis. Design, setting, and participants: A double-blind, randomized clinical trial enrolling critically ill patients with sepsis or septic shock who had been prescribed meropenem by their treating clinicians at 31 intensive care units of 26 hospitals in 4 countries (Croatia, Italy, Kazakhstan, and Russia). Patients were enrolled between June 5, 2018, and August 9, 2022, and the final 90-day follow-up was completed in November 2022. Interventions: Patients were randomized to receive an equal dose of the antibiotic meropenem by either continuous administration (n = 303) or intermittent administration (n = 304). Main outcomes and measures: The primary outcome was a composite of all-cause mortality and emergence of pandrug-resistant or extensively drug-resistant bacteria at day 28. There were 4 secondary outcomes, including days alive and free from antibiotics at day 28, days alive and free from the intensive care unit at day 28, and all-cause mortality at day 90. Seizures, allergic reactions, and mortality were recorded as adverse events. Results: All 607 patients (mean age, 64 [SD, 15] years; 203 were women [33%]) were included in the measurement of the 28-day primary outcome and completed the 90-day mortality follow-up. The majority (369 patients, 61%) had septic shock. The median time from hospital admission to randomization was 9 days (IQR, 3-17 days) and the median duration of meropenem therapy was 11 days (IQR, 6-17 days). Only 1 crossover event was recorded. The primary outcome occurred in 142 patients (47%) in the continuous administration group and in 149 patients (49%) in the intermittent administration group (relative risk, 0.96 [95% CI, 0.81-1.13], P = .60). Of the 4 secondary outcomes, none was statistically significant. No adverse events of seizures or allergic reactions related to the study drug were reported. At 90 days, mortality was 42% both in the continuous administration group (127 of 303 patients) and in the intermittent administration group (127 of 304 patients). Conclusions and relevance: In critically ill patients with sepsis, compared with intermittent administration, the continuous administration of meropenem did not improve the composite outcome of mortality and emergence of pandrug-resistant or extensively drug-resistant bacteria at day 28. Trial registration: ClinicalTrials.gov Identifier: NCT03452839

Repair techniques used in two existing collar beam trusses: experimental results of full size scale tests

Pre-print versionStructural strengthening and repair of old timber structures may be necessary due to new needs of use or due to the past history of the structure. In both cases, a thorough understanding of the present structure must be available in order to ascertain the best form of intervention. Depending on the performance and social parameters, some intervention solutions may be more adequate than others. In this work, two collar beam trusses were studied regarding their performance on full scale laboratory tests. The trusses were tested with their original conditions and after different interventions. The interventions consisted on the strengthening of the support region, local repairs using timber elements and screwed metal plates and finally on a global intervention with post-tensioned steel cables. The strengthening of the support region allowed to obtain a higher load level, while the local retrofitting of elements allowed to regain at least 80% of the original load level. The global intervention also allowed a recovery of more than 80%.FEDER funds through the Competitivity Factors Operational Programme-COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-00763

Identification of bone marrow edema of the knee: diagnostic accuracy of dual-energy CT in comparison with MRI

To assess the diagnostic accuracy of dual-energy computed tomography (DECT) in diagnosing bone marrow edema (BME) of the knee in traumatic and non-traumatic patients

32-Channel silicon strip detection module for combined X-ray fluorescence spectroscopy and X-ray diffractometry analysis

A compact detection module for the simultaneous measurement of XRF and XRD in portable analytical applications, in particular in the mining sector, is presented. The detector head is based on 32 silicon strip detectors, fabricated with a low-leakage technology by FBK and readout by two 16-channel low noise CUBE charge-sensitive amplifiers. The design of the module and its characterization are reported. Multiple configurations are experimentally compared in terms of strip length, spacing, collimation and charge sharing effects. The optimal configuration for a strip length of 6mm and pitch 0.2mm is thus identified. It offers an energy resolution of better than 200 eV at 5.9 keV with moderate cooling (−10°C) and peaking time of 14 μs

Characteristics, treatment, outcomes and cause of death of invasively ventilated patients with COVID-19 ARDS in Milan, Italy

OBJECTIVE: Describe characteristics, daily care and outcomes of patients with coronavirus disease 2019 (COVID-19) acute respiratory distress syndrome (ARDS). DESIGN: Case series of 73 patients. SETTING: Large tertiary hospital in Milan. PARTICIPANTS: Mechanically ventilated patients with confirmed COVID-19 admitted to the intensive care unit (ICU) between 20 February and 2 April 2020. MAIN OUTCOME MEASURES: Demographic and daily clinical data were collected to identify predictors of early mortality. RESULTS: Of the 73 patients included in the study, most were male (83.6%), the median age was 61 years (interquartile range [IQR], 54-69 years), and hypertension affected 52.9% of patients. Lymphocytopenia (median, 0.77 x 103 per mm3; IQR, 0.58-1.00 x 103 per mm3), hyperinflammation with C-reactive protein (median, 184.5 mg/dL; IQR, 108.2-269.1 mg/dL) and pro-coagulant status with D-dimer (median, 10.1 μg/m; IQR, 5.0-23.8 μg/m) were present. Median tidal volume was 6.7 mL/kg (IQR, 6.0-7.5 mL/kg), and median positive end-expiratory pressure was 12 cmH2O (IQR, 10-14 cmH2O). In the first 3 days, prone positioning (12-16 h) was used in 63.8% of patients and extracorporeal membrane oxygenation in five patients (6.8%). After a median follow-up of 19.0 days (IQR, 15.0-27.0 days), 17 patients (23.3%) had died, 23 (31.5%) had been discharged from the ICU, and 33 (45.2%) were receiving invasive mechanical ventilation in the ICU. Older age (odds ratio [OR], 1.12; 95% CI, 1.04-1.22; P = 0.004) and hypertension (OR, 6.15; 95% CI, 1.75-29.11; P = 0.009) were associated with mortality, while early improvement in arterial partial pressure of oxygen (PaO2) to fraction of inspired oxygen (FiO2) ratio was associated with being discharged alive from the ICU (P = 0.002 for interaction). CONCLUSIONS: Despite multiple advanced critical care interventions, COVID-19 ARDS was associated with prolonged ventilation and high short term mortality. Older age and pre-admission hypertension were key mortality risk factors. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04318366

High-Resolution Photoemission Study of Neutron-Induced Defects in Amorphous Hydrogenated Silicon Devices

In this paper, by means of high-resolution photoemission, soft X-ray absorption and atomic force microscopy, we investigate, for the first time, the mechanisms of damaging, induced by neutron source, and recovering (after annealing) of p-i-n detector devices based on hydrogenated amorphous silicon (a-Si:H). This investigation will be performed by mean of high-resolution photoemission, soft X-Ray absorption and atomic force microscopy. Due to dangling bonds, the amorphous silicon is a highly defective material. However, by hydrogenation it is possible to reduce the density of the defect by several orders of magnitude, using hydrogenation and this will allow its usage in radiation detector devices. The investigation of the damage induced by exposure to high energy irradiation and its microscopic origin is fundamental since the amount of defects determine the electronic properties of the a-Si:H. The comparison of the spectroscopic results on bare and irradiated samples shows an increased degree of disorder and a strong reduction of the Si-H bonds after irradiation. After annealing we observe a partial recovering of the Si-H bonds, reducing the disorder in the Si (possibly due to the lowering of the radiation-induced dangling bonds). Moreover, effects in the uppermost coating are also observed by spectroscopies

Fabrication of a hydrogenated amorphous silicon detector in 3-d geometry and preliminary test on planar prototypes

Hydrogenated amorphous silicon (a-Si:H) can be produced by plasma-enhanced chemical vapor deposition (PECVD) of SiH4 (silane) mixed with hydrogen. The resulting material shows outstanding radiation hardness properties and can be deposited on a wide variety of substrates. Devices employing a-Si:H technologies have been used to detect many different kinds of radiation, namely, minimum ionizing particles (MIPs), X-rays, neutrons, and ions, as well as low-energy protons and alphas. However, the detection of MIPs using planar a-Si:H diodes has proven difficult due to their unsatisfactory S/N ratio arising from a combination of high leakage current, high capacitance, and limited charge collection efficiency (50% at best for a 30 µm planar diode). To overcome these limitations, the 3D-SiAm collaboration proposes employing a 3D detector geometry. The use of vertical electrodes allows for a small collection distance to be maintained while preserving a large detector thickness for charge generation. The depletion voltage in this configuration can be kept below 400 V with a consequent reduction in the leakage current. In this paper, following a detailed description of the fabrication process, the results of the tests performed on the planar p-i-n structures made with ion implantation of the dopants and with carrier selective contacts are illustrated