Influence of vibratory stress relief on residual stresses in weldments and mechanical properties of struktural steel joint

The welding process can join two similar materials with a bond that has mechanical properties comparable to the original material. Unfortunately, this process induces residual stresses in the weldment, which, if left untreated, can cause distortion of the part, premature fatigue failure or cracking along the weld. A post-weld heat treatment is the traditional method of relieving these stresses, but is costly and a time consuming process. Heat treatment is required for weldments, which have heavy fatigue loading since the post-weld heat treatment reduces the residual stresses in the weldment and generates more uniform mechanical properties. Vibratory stress relief (VSR) techniques could be used to substitute the heat treatment for these types of weldments and save time and money. The purpose of this paper is to provide a brief overview of the generation, measurement, and reduction of residual stresses. Residual stresses in the weld bead were measured by means of X-ray diffraction, ultrasonic technique and hole drilling methods. In addition, welded specimens were subjected to mechanical testing with purpose of determination of VSR effect on weld and heat-affected zone meta

Pediatric antibiotic stewardship programs in Europe: a pilot survey among delegates of The European Academy of Pediatrics

BackgroundAntimicrobial resistance (AMR) is one of the leading causes of morbidity and mortality worldwide. Efforts to promote the judicious use of antibiotics and contain AMR are a priority of several medical organizations, including the WHO. One effective way to achieve this goal is the deployment of antibiotic stewardship programs (ASPs). This study aimed to survey the current situation of pediatric ASPs in European countries and establish a baseline for future attempts to harmonize pediatric ASPs and antibiotic use in Europe.MethodsA web-based survey was conducted among national delegates of the European Academy of Paediatrics (EAP). The survey assessed the presence of pediatric ASPs in the representatives’ countries in the inpatient and outpatient settings, the staff included in the programs, and their detailed activities regarding antibiotic use.ResultsOf the 41 EAP delegates surveyed, 27 (66%) responded. Inpatient pediatric ASPs were reported in 74% (20/27) countries, and outpatient programs in 48% (13/27), with considerable variability in their composition and activities. Guidelines for managing pediatric infectious diseases were available in nearly all countries (96%), with those for neonatal infections (96%), pneumonia (93%), urinary tract (89%), peri-operative (82%), and soft tissue (70%) infections being the most common. Pediatric ASPs were reported at the national (63%), institutional (41%), and regional/local (<15%) levels. Pediatricians with infectious disease training (62%) and microbiologists (58%) were the most common members of the program personnel, followed by physician leaders (46%), infectious disease/infection control physicians (39%), pharmacists (31%), and medical director representatives (15%). Activities of the pediatric ASPs included educational programs (85%), monitoring and reporting of antibiotic use (70%) and resistance (67%), periodic audits with feedback (44%), prior approval (44%), and post-prescription review of selected antibiotic agents (33%).ConclusionAlthough pediatric ASPs exist in most European countries, their composition and activities vary considerably across countries. Initiatives to harmonize comprehensive pediatric ASPs across Europe are needed

Three-Wave Modulational Stability and Dark Solitons in a Quadratic Nonlinear Waveguide with Grating

We consider continuous-wave (CW) states and dark solitons (DSs) in a system of two fundamental-frequency (FF) and one second-harmonic (SH) waves in a planar waveguide with the quadratic nonlinearity, the FF components being linearly coupled by resonant reflections on the Bragg grating. We demonstrate that, in contrast with the usual situation in quadratic spatial-domain models, CW states with the phase shift between the FF and SH components are modulationally stable in a broad parameter region in this system, provided that the CW wavenumber does not belong to the system's spectral gap. Stationary fundamental DSs are found numerically, and are also constructed by means of a specially devised analytical approximation. Bound states of two and three DSs are found too. The fundamental DSs and two-solitons bound states are stable in all the cases when the CW background is stable, which is shown by dint of calculation of the corresponding eigenvalues, and verified in direct simulations. Tilted DSs are found too. They attain a maximum contrast at a finite value of the tilt, that does not depend on the phase mismatch. At a maximum value of the tilt, which grows with the mismatch, the DS merges into the CW background. Interactions between the tilted solitons are shown to be completely elastic.Comment: 10 pages, 12 figures; Journal of Optics A, in pres

Available and affordable complementary treatments for COVID-19 : From hypothesis to pilot studies and the need for implementation

Vaccination is a highly effective preventive measure against COVID-19. However, complementary treatments are needed to better control the disease. Fermented vegetables and spices, agonists of the antioxidant transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and TRPA1/V1 channels (Transient Receptor Potential Ankyrin 1 and Vanillin 1), may help in the control of COVID-19. Some preliminary clinical trials suggest that curcumin (spice) can prevent some of the COVID-19 symptoms. Before any conclusion can be drawn and these treatments recommended for COVID-19, the data warrant confirmation. In particular, the benefits of the foods need to be assessed in more patients, through research studies and large trials employing a double-blind, placebo-controlled design.Peer reviewe

Filamentation and Pulse Self-compression in the Anomalous Dispersion Region of Glasses

International audienceThe propagation of near-infrared ultra-short laser pulses in the regime of anomalous dispersion of transparent solids is associated with a host of self-induced effects including a significant spectral broadening extending from the ultraviolet into the infrared region, pulse self-compression down to few-cycle pulse durations, free and driven third harmonic generation, conical emission and the formation of stable filaments over several cm showing the emergence of conical light bullets. We review measurements performed in different experimental conditions and results of numerical simulations of unidirectional propagation models showing that the interpretation of all these phenomena proceed from the formation of non-spreading conical light bullets during filamentation

Vilnius Declaration on chronic respiratory diseases : multisectoral care pathways embedding guided self-management, mHealth and air pollution in chronic respiratory diseases

Correction: Volume: 10 Issue: 1 Article Number: 49 DOI: 10.1186/s13601-020-00357-4 Published: DEC 17 2020Background: Over 1 billion people suffer from chronic respiratory diseases such as asthma, COPD, rhinitis and rhinosinusitis. They cause an enormous burden and are considered as major non-communicable diseases. Many patients are still uncontrolled and the cost of inaction is unacceptable. A meeting was held in Vilnius, Lithuania (March 23, 2018) under the patronage of the Ministry of Health and several scientific societies to propose multisectoral care pathways embedding guided self-management, mHealth and air pollution in selected chronic respiratory diseases (rhinitis, chronic rhinosinusitis, asthma and COPD). The meeting resulted in the Vilnius Declaration that was developed by the participants of the EU Summit on chronic respiratory diseases under the leadership of Euforea. Conclusion: The Vilnius Declaration represents an important step for the fight against air pollution in chronic respiratory diseases globally and has a clear strategic relevance with regard to the EU Health Strategy as it will bring added value to the existing public health knowledge.Peer reviewe

Efficacy of broccoli and glucoraphanin in COVID-19: From hypothesis to proof-of-concept with three experimental clinical cases

COVID-19 is described in a clinical case involving a patient who proposed the hypothesis that Nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-interacting nutrients may help to prevent severe COVID-19 symptoms. Capsules of broccoli seeds containing glucoraphanin were being taken before the onset of SARS-CoV-2 infection and were continued daily for over a month after the first COVID-19 symptoms. They were found to reduce many of the symptoms rapidly and for a duration of 6-12 h by repeated dosing. When the patient was stable but still suffering from cough and nasal obstruction when not taking the broccoli capsules, a double-blind induced cough challenge confirmed the speed of onset of the capsules (less than 10 min). A second clinical case with lower broccoli doses carried out during the cytokine storm confirmed the clinical benefits already observed. A third clinical case showed similar effects at the onset of symptoms. In the first clinical trial, we used a dose of under 600 mmol per day of glucoraphanin. However, such a high dose may induce pharmacologic effects that require careful examination before the performance of any study. It is likely that the fast onset of action is mediated through the TRPA1 channel. These experimental clinical cases represent a proof-of-concept confirming the hypothesis that Nrf2interacting nutrients are effective in COVID-19. However, this cannot be used in practice before the availability of further safety data, and confirmation is necessary through proper trials on efficacy and safety.Peer reviewe

Pulsed quadrature-phase squeezing of solitary waves in chi((2)) parametric waveguides

It is shown that coherent quantum simultons (simultaneous solitary waves at two different frequencies) can undergo quadrature-phase squeezing as they propagate through a dispersive chi((2)) waveguide. This requires a treatment of the coupled quantized fields including a quantized depleted pump field. A technique involving nonlinear stochastic parabolic partial differential equations using a nondiagonal coherent state representation in combination with an exact Wigner representation on a reduced phase space is outlined. We explicitly demonstrate that group-velocity matched chi((2)) waveguides which exhibit collinear propagation can produce quadrature-phase squeezed simultons. Quasi-phase-matched KTP waveguides, even with their large group-velocity mismatch between fundamental and second harmonic at 425 nm, can produce 3 dB squeezed bright pulses at 850 nm in the large phase-mismatch regime. This can be improved to more than 6 dB by using group-velocity matched waveguides