A method to replace lightning strike tests by ball impacts in the design process of lightweight composite aircraft panels

Composite material aircrafts are protected against lightning on the basis of complex and expansive lightning strike experimental plans aiming at designing optimal protections. The paper aims at reducing the number of lightning strike tests on protected and painted composite panels. An analytical calculation is presented that gives the characteristics of an equivalent mechanical impact configuration based on an assessment of the typical time scale of energy deposit and kinematic behaviour during a lightning strike test. The paper presents our analytical hypotheses and calculations, as well as experimental lighting strikes and mechanical impact settings and results. The method is shown to give an acceptable approximation of both the kinematics and the delamination surface

Experimental investigation of the repeatability of direct damage induced by lightning strikes on metallic panels

Metallic parts of aircrafts used for fuel tanks areas or even for the fuselage can suffer from severe direct damage due to lightning strikes. Metallic aircrafts are naturally protected against current flows because of their high electrical conductivity. But at the arc attachment location, there is a major risk of perforation which can result in a dramatic explosion due to fuel tank ignition. A lightning strike is a current discharge between opposite charge locations inside clouds and on the ground. Currents under considerations here are D+B+C* current waveforms prescribed by the standard regulations and reproduced in by specific current delivery devices at DGA-Ta lightning lab. It is well known that the risk to perforate a metallic panel directly increases with the duration of the C* component, mainly because of heat transfer at the arc root. But it is nevertheless not well understood how the variability of the test parameters of the electrical charge and the electro-thermo-mechanical behaviour of the structure influence the variability of the critical perforation point. This paper presents the analysis synthesis of experimental investigations on the risk of perforation of a metallic panel to a laboratory prescribed D+B+C* lightning strike. A sensitivity analysis compares different tests campaigns and gives insight into the damage patterns related to perforation risk grades. The effect of the variability of some lab test parameters is reported. It is shown that a linear but not monotonously increasing relationship exists between the damaged zone in the panel and the delivered current charge. The perforation risk is shown to be not proportional to the current charge but rather to damage instability

Functional genomic analysis unravels a metabolic-inflammatory interplay in adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is an inherited disorder characterized by axonopathy and demyelination in the central nervous system and adrenal insufficiency. Main X-ALD phenotypes are: (i) an adult adrenomyeloneuropathy (AMN) with axonopathy in spinal cords, (ii) cerebral AMN with brain demyelination (cAMN) and (iii) a childhood variant, cALD, characterized by severe cerebral demyelination. Loss of function of the ABCD1 peroxisomal fatty acid transporter and subsequent accumulation of very-long-chain fatty acids (VLCFAs) are the common culprits to all forms of X-ALD, an aberrant microglial activation accounts for the cerebral forms, whereas inflammation allegedly plays no role in AMN. How VLCFA accumulation leads to neurodegeneration and what factors account for the dissimilar clinical outcomes and prognosis of X-ALD variants remain elusive. To gain insights into these questions, we undertook a transcriptomic approach followed by a functional-enrichment analysis in spinal cords of the animal model of AMN, the Abcd1− null mice, and in normal-appearing white matter of cAMN and cALD patients. We report that the mouse model shares with cAMN and cALD a common signature comprising dysregulation of oxidative phosphorylation, adipocytokine and insulin signaling pathways, and protein synthesis. Functional validation by quantitative polymerase chain reaction, western blots and assays in spinal cord organotypic cultures confirmed the interplay of these pathways through IkB kinase, being VLCFA in excess a causal, upstream trigger promoting the altered signature. We conclude that X-ALD is, in all its variants, a metabolic/inflammatory syndrome, which may offer new targets in X-ALD therapeutics

Gain-of-function human STAT1 mutations impair IL-17 immunity and underlie chronic mucocutaneous candidiasis

Chronic mucocutaneous candidiasis disease (CMCD) may be caused by autosomal dominant (AD) IL-17F deficiency or autosomal recessive (AR) IL-17RA deficiency. Here, using whole-exome sequencing, we identified heterozygous germline mutations in STAT1 in 47 patients from 20 kindreds with AD CMCD. Previously described heterozygous STAT1 mutant alleles are loss-of-function and cause AD predisposition to mycobacterial disease caused by impaired STAT1-dependent cellular responses to IFN-γ. Other loss-of-function STAT1 alleles cause AR predisposition to intracellular bacterial and viral diseases, caused by impaired STAT1-dependent responses to IFN-α/β, IFN-γ, IFN-λ, and IL-27. In contrast, the 12 AD CMCD-inducing STAT1 mutant alleles described here are gain-of-function and increase STAT1-dependent cellular responses to these cytokines, and to cytokines that predominantly activate STAT3, such as IL-6 and IL-21. All of these mutations affect the coiled-coil domain and impair the nuclear dephosphorylation of activated STAT1, accounting for their gain-of-function and dominance. Stronger cellular responses to the STAT1-dependent IL-17 inhibitors IFN-α/β, IFN-γ, and IL-27, and stronger STAT1 activation in response to the STAT3-dependent IL-17 inducers IL-6 and IL-21, hinder the development of T cells producing IL-17A, IL-17F, and IL-22. Gain-of-function STAT1 alleles therefore cause AD CMCD by impairing IL-17 immunity

Autoantibodies against type I IFNs in patients with critical influenza pneumonia

In an international cohort of 279 patients with hypoxemic influenza pneumonia, we identified 13 patients (4.6%) with autoantibodies neutralizing IFN-alpha and/or -omega, which were previously reported to underlie 15% cases of life-threatening COVID-19 pneumonia and one third of severe adverse reactions to live-attenuated yellow fever vaccine. Autoantibodies neutralizing type I interferons (IFNs) can underlie critical COVID-19 pneumonia and yellow fever vaccine disease. We report here on 13 patients harboring autoantibodies neutralizing IFN-alpha 2 alone (five patients) or with IFN-omega (eight patients) from a cohort of 279 patients (4.7%) aged 6-73 yr with critical influenza pneumonia. Nine and four patients had antibodies neutralizing high and low concentrations, respectively, of IFN-alpha 2, and six and two patients had antibodies neutralizing high and low concentrations, respectively, of IFN-omega. The patients' autoantibodies increased influenza A virus replication in both A549 cells and reconstituted human airway epithelia. The prevalence of these antibodies was significantly higher than that in the general population for patients 70 yr of age (3.1 vs. 4.4%, P = 0.68). The risk of critical influenza was highest in patients with antibodies neutralizing high concentrations of both IFN-alpha 2 and IFN-omega (OR = 11.7, P = 1.3 x 10(-5)), especially those <70 yr old (OR = 139.9, P = 3.1 x 10(-10)). We also identified 10 patients in additional influenza patient cohorts. Autoantibodies neutralizing type I IFNs account for similar to 5% of cases of life-threatening influenza pneumonia in patients <70 yr old

Traditionally trained acupuncturists’ views on the World Health Organization traditional medicine ICD-11 codes: A Europe wide mixed methods study

Introduction: The diagnostic categories used in Traditional Medicine (TM) that originated in China and are now used around the world have been classified for inclusion as a chapter within the World Health Organization's International Classification of Diseases (ICD). As a new chapter in ICD, the TM ICD codes were subject to international field testing. A pilot field test of the TM ICD codes was conducted to investigate their clinical utility in the European context. Design: A mixed methods approach, including a Europe wide survey of practitioner views on TM ICD codes; and investigating the coding process of case study vignettes to explore coders’ experiences of using TM ICD codes. Results: Survey: The majority of participants felt TM ICD codes provide a meaningful way to classify TM disorders and patterns; felt their patients’ diagnoses could be represented within the codes; and felt the codes would be important in their clinical practice. Coding of vignettes: In 60.7% of cases the specificity of the assigned code was perceived as ‘just right’. Participants experienced difficulties assigning a single TM ICD disorder and pattern code, due to multiple codes being viewed as appropriate for the case. Conclusions: The European TM practitioners who participated in this study largely perceive the TM ICD codes as valuable, conceptually accurate, and incorporating the range of TM diagnoses utilized within clinical practice. The TM ICD codes could be improved for European TM practitioners by expanding the scope of TM ICD codes, and adopting a multidimensional approach whereby more than one disorder and/or pattern code can be applied to single patients.</p

Experimental investigation of the repeatability of direct damage induced by lightning strikes on metallic panels

International audienceMetallic parts of aircrafts used for fuel tanks areas or even for the fuselage can suffer from severe direct damage due to lightning strikes. Metallic aircrafts are naturally protected against current flows because of their high electrical conductivity. But at the arc attachment location, there is a major risk of perforation which can result in a dramatic explosion due to fuel tank ignition. A lightning strike is a current discharge between opposite charge locations inside clouds and on the ground. Currents under considerations here are D+B+C* current waveforms prescribed by the standard regulations and reproduced in by specific current delivery devices at DGA-Ta lightning lab. It is well known that the risk to perforate a metallic panel directly increases with the duration of the C* component, mainly because of heat transfer at the arc root. But it is nevertheless not well understood how the variability of the test parameters of the electrical charge and the electro-thermo-mechanical behaviour of the structure influence the variability of the critical perforation point. This paper presents the analysis synthesis of experimental investigations on the risk of perforation of a metallic panel to a laboratory prescribed D+B+C* lightning strike. A sensitivity analysis compares different tests campaigns and gives insight into the damage patterns related to perforation risk grades. The effect of the variability of some lab test parameters is reported. It is shown that a linear but not monotonously increasing relationship exists between the damaged zone in the panel and the delivered current charge. The perforation risk is shown to be not proportional to the current charge but rather to damage instability

Experimental investigation of the repeatability of direct damage induced by lightning strikes on metallic panels

International audienceMetallic parts of aircrafts used for fuel tanks areas or even for the fuselage can suffer from severe direct damage due to lightning strikes. Metallic aircrafts are naturally protected against current flows because of their high electrical conductivity. But at the arc attachment location, there is a major risk of perforation which can result in a dramatic explosion due to fuel tank ignition. A lightning strike is a current discharge between opposite charge locations inside clouds and on the ground. Currents under considerations here are D+B+C* current waveforms prescribed by the standard regulations and reproduced in by specific current delivery devices at DGA-Ta lightning lab. It is well known that the risk to perforate a metallic panel directly increases with the duration of the C* component, mainly because of heat transfer at the arc root. But it is nevertheless not well understood how the variability of the test parameters of the electrical charge and the electro-thermo-mechanical behaviour of the structure influence the variability of the critical perforation point. This paper presents the analysis synthesis of experimental investigations on the risk of perforation of a metallic panel to a laboratory prescribed D+B+C* lightning strike. A sensitivity analysis compares different tests campaigns and gives insight into the damage patterns related to perforation risk grades. The effect of the variability of some lab test parameters is reported. It is shown that a linear but not monotonously increasing relationship exists between the damaged zone in the panel and the delivered current charge. The perforation risk is shown to be not proportional to the current charge but rather to damage instability