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In this work, the syntheses and characterization by mechanical and dielectric spectroscopies of (1-x) Bi0.5Na0.5TiO3-xBaTiO3 (BNT-100xBT), with x = 0.05, 0.06 and 0.07, lead-free piezoelectric ceramics is reported. Ceramic samples of BNT-BT have been prepared by mixed-oxide method and then conventionally sintered. X-ray diffraction patterns of sintered samples, indicated for BNT-7BT the presence of tetragonal (P4mm) complex perovskite structure, whereas for BNT-5BT and BNT-6BT the samples exhibit a mixture of tetragonal (P4mm) and rhombohedral (R3c) crystalline phases, which reveal the presence of a morphotropic phase boundary (MPB) in the BNT-BT system. Measurements of internal friction, Q-1, and the storage modulus, E’, as a function of temperature at various frequencies were carried out in a Dynamic Mechanical Analyzer (DMA), in the temperature range from 0ºC to 600ºC. Dielectric profiles are recorded in the frequency range from 1kHz to 100kHz and the temperature range from room temperature to 475ºC. Mechanical loss spectra obtained for investigated compositions of BNT-BT samples showed different frequency-independent anomalies. Two main anomalies for BNT-5BT and BNT-6BT, observed around 100ºC and 430ºC were associated with the ferroelectric-antiferroelectric and antiferroelectricparaelectric phase transitions, respectively. The results obtained from mechanical loss measurements were supported by dielectric relaxation spectra. For BNT-7BT, outside the MPB, four different frequency-independent processes were observed.

A study was conducted to analyze the dielectric behavior of lead niobate ferroelectric, Pb[Nb.sub.2][O.sub.6] (PN) ceramics in the frequency range of 20 Hz-2 GHz. The two dielectric dispersion processes, the low- and high-frequency dispersions were found to be associated with the contribution of the point defects, related to the lead losses during the sintering process and to the dynamics of polar regions boundaries, respectively.

Characteristics of phase transitions of lead barium niobate compositions around the morphotropic phase boundary were investigated. Using structural characterizations, it was found that the morphotropic phase boundary extends toward a wide composition range, in which both tetragonal (4mm) and orthorhombic (m2m) tungsten bronze phases coexist. In addition, on heating, two phase transitions were observed for all the studied compositions. First, the fraction with m2m symmetry phase transforms into the 4mm symmetry one and, second, the 4mm symmetry phase, which represents the whole material, transforms into the paraelectric phase (4/mmm symmetry). The phase transition temperatures were determined from dielectric characterizations. These results helped to improve the phase diagram of the pseudobinary PbNb2O6–BaNb2O6 system around the morphotropic phase boundary region. [ABSTRACT FROM AUTHOR]

High Curie temperature ferroelectrics are promising materials to construct transducers for high-temperature piezoelectric applications. Among them, the lead niobate system is one that displays such characteristic. In this work, the dielectric behavior of lead niobate ferroelectric ceramics was analyzed in the frequency range of 20 Hz-2 GHz. Ceramic samples with nominal formula PbNb2O6 (PN) were prepared by the solid-state reaction method. The phase transition was investigated with the Santos-Eiras’ phenomenological model. The values of the parameter, which determine the phase transition character (ξ), are close to 1, indicating a conventional ferroelectric phase transition. The PN materials showed two different dispersion processes: (1) a typical high-frequency dispersion process, which may be associated with the polar region boundaries dynamics, as observed in ferroelectric materials in the microwave frequency region, and (2) that associated with the charge carrier conduction, observed in the lowest frequencies and high-temperature region. An additional dispersion process, in the intermediate frequency range (around 2 MHz), was identified, which may be related to the overlapping between both the normal dipolar process (characteristic of the dipolar materials) and the strong low-frequency conductive process. [ABSTRACT FROM AUTHOR]

The characteristics of phase transitions of lead barium niobate compositions around the morphotropic phase boundary are examined. The phase transition temperatures are determined from dielectric characterizations and the results have improved the phase diagram of the pseudobinary Pb[Nb.sub.2][O.sub.6]-Ba[Nb.sub.2][O.sub.6] system around the morphotropic phase boundary region.

Ceramic composites based on Pb(Zr,Ti)O3/NiFe2O4 (PZT–NFO) have been synthesized from the conventional solid-state reaction method. The ferroelectric and magnetic properties have been investigated at room temperature. The obtained results revealed excellent characteristics of both ferroic responses, which suggest the studied ceramic composite as a promising material for practical applications in magneto-electric related devices. [ABSTRACT FROM AUTHOR]

The low-temperature sintering and electric properties of Pb0.99( Zr0.95 Ti0.05)0.98 Nb0.02 O3 ( PZTN 95/5) ferroelectric ceramics with CuO addition was investigated. The CuO addition significantly promoted the densification and reduced the sintering temperature of PZTN 95/5 ceramics by more than 200°C. The 0.2 wt% CuO-added sample sintered at 1150°C exhibited the optimum relative density of 96.7% and excellent electric properties with values of Pr = 37.80 μC/cm2, TC = 223°C, εr = 329, and tan δ = 0.016, which were superior to that of PZTN 95/5 ceramics sintered at 1350°C. [ABSTRACT FROM AUTHOR]

The article presents a study on the development of an equipment for non-destructive characterization of elastic moduli that is applicable to ceramics, concretes, and brittle materials based on American Society for Testing Materials (ASTM) standard. The study used the sonic resonance spectroscopy to measure the natural torsional and flexural vibration frequencies of the sample. The result shows that the equipment is more versatile than the current options to the measurement of the elastic moduli.

The processing of a PbNb2O6 (PN) ceramic was investigated and optimized. Through thermal gravimetric and X-ray diffraction analysis the optimal calcination condition and the starting firing temperature were estimated. The powders were submitted to thermal treatments to obtain PN ceramic powders with an orthorhombic ferroelectric phase. The effect of PbO excess addition to compensate the PbO losses, during the calcination and the firing, was also studied. The highest density value was found to be 96% of the theoretical density. The temperature dependence of the dielectric properties, for samples sintered at different temperatures, allowed the study of the sintering kinetic. [ABSTRACT FROM AUTHOR]

The FeAlO 3 phase presents an orthorhombic symmetry (Pna21 space group) with a double combination of hexagonal and cubic closed packing of oxygen ions. In this phase, there are four distorted different cationic sites, promoting piezoelectricity, ferrimagnetism and magnetoelectric effects at low temperatures. In this work, high-energy ball milling was employed to produce the FeAlO 3 multiferroic compound. Its structural (Rietveld refinement), dielectric and magnetic properties were carefully investigated. [ABSTRACT FROM AUTHOR]

Multiferroic BiFeO 3 ceramic powders were synthesized through high-energy ball milling. The structural, microstructural and magnetic properties of the obtained samples were carefully determined. The obtained samples were very fractured and strained due to the employed milling conditions, motivating the agglomeration of the nanopowders. The unit cell, Mössbauer and magnetic parameters presented considerable alterations in comparison with those for bulk materials, as a consequence of mechanosynthesis. The modification of BiFeO 3 with 5 mol% of Mn ions do not induces significant microstructural or structural alterations in as-milled or annealed samples. However, an intense magnetization decreasing was observed. [ABSTRACT FROM AUTHOR]

In this work, pure and La 3+ -doped PBN56 ceramics (La 3+ added from 0 wt% to 4 wt%) were fabricated and studied concerning its structure, microstructure and dielectric properties. The analysis of the microstructure of the ceramics showed a change of the grain morphology for ceramics with La content higher than 1.0 wt%. X-ray diffraction and Raman spectroscopy were performed to study the structure of the PBN56 ceramics. The results showed the presence of an orthorhombic phase, whose concentration is increased with the increasing of the La 3+ content. The analysis of the results was performed to investigate the presence of the orthorhombic phase and the composition where its formation begins. [ABSTRACT FROM AUTHOR]

Abstract: Ferroelectric materials with high Curie temperature are highly desirable to construct transducers for high temperature piezoelectric applications. Among the ferroelectric materials PbNb2O6 (PN) is one that display such characteristic. However, the fabrication of high density PN ceramics is very difficult, which limited the use in piezoelectric transducers. In this paper high density (∼95%) Ti- and Ba-doped PN ceramics were prepared through the conventional ceramic method. The electromechanical coefficients, such as coupling (k 31, k 33) and quality factors (Q m), were measured and compared in the investigated materials. The properties of “pure” PN were comparable to those observed in Ti- and Ba-modified PN ceramics. The addition of Ba to the PN ceramics decreased the Curie temperature (as compared to the pure PN), limiting the applicability in piezoelectric transducers for temperatures below 350°C. On the other hand, the addition of titanium not only increases the Curie temperature, but also contributes to the increase of the densification of the PN ceramics. Results showed that Ti doped PN ceramics present a high potential to be used in high temperature applications as piezoelectric transducers. [Copyright &y& Elsevier]

All-trans-retinoic acid is a potent inhibitor of cell proliferation and inducer of differentiation. However, the clinical use of all-trans-retinoic acid in the treatment of cancer is significantly hampered by its toxicity and the prompt emergence of resistance, believed to be caused by increased all-trans-retinoic acid metabolism. Inhibitors of all-trans-retinoic acid metabolism may therefore prove valuable in the treatment of cancer. In this study, we characterize R116010 as a new anticancer drug that is a potent inhibitor of all-trans-retinoic acid metabolism. In vitro, R116010 potently inhibits all-trans-retinoic acid metabolism in intact T47D cells with an IC(50)-value of 8.7 nM. In addition, R116010 is a selective inhibitor as indicated by its inhibition profile for several other cytochrome P450-mediated reactions. In T47D cell proliferation assays, R116010 by itself has no effect on cell proliferation. However, in combination with all-trans-retinoic acid, R116010 enhances the all-trans-retinoic acid-mediated antiproliferative activity in a concentration-dependent manner. In vivo, the growth of murine oestrogen-independent TA3-Ha mammary tumours is significantly inhibited by R116010 at doses as low as 0.16 mg kg(-1). In conclusion, R116010 is a highly potent and selective inhibitor of all-trans-retinoic acid metabolism, which is able to enhance the biological activity of all-trans-retinoic acid, thereby exhibiting antitumour activity. R116010 represents a novel and promising anticancer drug with an unique mechanism of action. [ABSTRACT FROM AUTHOR]

Complex dielectric permittivity measurements in PbNb2O6 ceramics were performed in a frequency and temperature range of 1 kHz–1 MHz and from 15 to 900 K, respectively. The results revealed two dielectric anomalies showing typical characteristics of relaxor ferroelectric materials at cryogenic temperatures. Comparison with other tetragonal tungsten bronze (TTB) structure-type materials suggests the existence of successive phase transitions, which until now were not reported. The observed low temperature dielectric behaviors seem to be due to intrinsic physical characteristics related to the TTB structure. [ABSTRACT FROM AUTHOR]

Abstract: Ferroelectric materials with high Curie temperature are highly desirable to construct transducers for high temperature piezoelectric applications. Among them, the lead niobate system is one that displays such characteristic. In this work, the dielectric behavior of lead niobate ferroelectric ceramics was analyzed in the frequency range of 20Hz to 2GHz. Ceramic samples with nominal formula PbNb2O6 (PN) were prepared by the solid-state reaction method. The diffuse phase transition was investigated with the Santos–Eiras’ phenomenological model. The values of ξ are close to 1, indicating a conventional ferroelectric phase transition. A low frequency dispersion process, which may be associated to a conduction mechanism, was observed up to 50kHz. The PN materials show a typical high frequency dispersion process, which may be associated to the domain wall dynamic, as observed in ferroelectric materials in the microwave frequency region, rather than the nano-clusters relaxation process or low frequency dispersion. [Copyright &y& Elsevier]

Abstract: A lead-free FeAlO3 multiferroic magnetoelectric compound was obtained through the sol–gel technique with subsequent annealing in an oxidative atmosphere. Dielectric investigations revealed a frequency- and temperature-dependent dielectric anomaly, which can be probably coupled to the sample magnetic ordering at around 220 K. These results indicate that the lead-free FeAlO3 magnetoelectric compound, which has a lower environmental impact in comparison to other multiferroics, is a potential candidate to be employed in areas where the magnetoelectric effect can be exploited. [Copyright &y& Elsevier]

Ferroelectric polymorphic phase coexistence, associated with either the presence of a morphotropic phase boundary or a temperature-driven polymorphic phase transition, is currently acknowledged as the key to high piezoelectric activity and is searched when new perovskite materials are developed, like lead-free alternatives to state-of-the-art Pb(Zr,Ti)O3. This requires characterization tools that allow phase coexistence and transitions to be readily identified, among which measurements of the temperature dependences of Young's modulus and mechanical losses by dynamical mechanical analysis stand out as a powerful technique to complement standard electrical characterizations. We report here the application of this technique to (K1-xNax)NbO3-based materials, which are under extensive investigation as environmentally friendly high sensitivity piezoelectrics. The elastic anomalies associated with the different phase transitions are identified and are shown to be distinctively shifted in relation to the dielectric ones. The origin of this discrepancy is discussed with the help of temperature-dependent Raman spectroscopy and is proposed to be a characteristic of diffuse phase transitions. [ABSTRACT FROM AUTHOR]

Competing Interests: Conflicts of Interest None.

Background: Right ventricular (RV) hemodynamic performance determines the prognosis of patients with RV pressure overload. Using ultrafast ultrasound, natural wave velocity (NWV) induced by cardiac valve closure was proposed as a new surrogate to quantify myocardial stiffness., Objectives: This study aimed to assess RV NWV in rodent models and children with RV pressure overload vs control subjects and to correlate NWV with RV hemodynamic parameters., Methods: Six-week-old rats were randomized to pulmonary artery banding (n = 6), Sugen hypoxia-induced pulmonary arterial hypertension (n = 7), or sham (n = 6) groups. They underwent natural wave imaging, echocardiography, and hemodynamic assessment at baseline and 6 weeks postoperatively. The authors analyzed NWV after tricuspid and after pulmonary valve closure (TVC and PVC, respectively). Conductance catheters were used to generate pressure-volume loops. In parallel, the authors prospectively recruited 14 children (7 RV pressure overload; 7 age-matched control subjects) and compared RV NWV with echocardiographic and invasive hemodynamic parameters., Results: NWV significantly increased in RV pressure overload rat models (4.99 ± 0.27 m/s after TVC and 5.03 ± 0.32 m/s after PVC in pulmonary artery banding at 6 weeks; 4.89 ± 0.26 m/s after TVC and 4.84 ± 0.30 m/s after PVC in Sugen hypoxia at 6 weeks) compared with control subjects (2.83 ± 0.15 m/s after TVC and 2.72 ± 0.34 m/s after PVC). NWV after TVC correlated with both systolic and diastolic parameters including RV dP/dt max (r = 0.75; P < 0.005) and RV Ees (r = 0.81; P < 0.005). NWV after PVC correlated with both diastolic and systolic parameters and notably with RV end-diastolic pressure (r = 0.65; P < 0.01). In children, NWV after both right valves closure in RV pressure overload were higher than in healthy volunteers (P < 0.01). NWV after PVC correlated with RV E/E' (r = 0.81; P = 0.008) and with RV chamber stiffness (r = 0.97; P = 0.03)., Conclusions: Both RV early-systolic and early-diastolic myocardial stiffness show significant increase in response to pressure overload. Based on physiology and our observations, early-systolic myocardial stiffness may reflect contractility, whereas early-diastolic myocardial stiffness might be indicative of diastolic function., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024. Published by Elsevier Inc.)

Background: Pediatric hypertrophic cardiomyopathy (HCM) is associated with adverse events. The contribution of diastolic dysfunction to adverse events is poorly understood. The aim of this study was to explore the association between diastolic phenotype and outcomes in pediatric patients with HCM., Methods: Children <18 years of age with diagnosed with HCM were included. Diastolic function parameters were measured from the first echocardiogram at the time of diagnosis, including Doppler flow velocities, tissue Doppler velocities, and left atrial volume and function. Using principal-component analysis, key features in echocardiographic parameters were identified. The principal components were regressed to freedom from major adverse cardiac events (MACE), defined as implantable cardioverter-defibrillator insertion, myectomy, aborted sudden cardiac death, transplantation, need for mechanical circulatory support, and death., Results: Variables that estimate left ventricular filling pressures were highly collinear and associated with MACE (hazard ratio, 0.86; 95% CI, 0.75-1.00), though this was no longer significant after controlling for left ventricular thickness and genetic variation. Left atrial size parameters adjusted for body surface area were independently associated with outcomes in the covariate-adjusted model (hazard ratio, 0.69; 95% CI, 0.5-0.94). The covariate-adjusted model had an Akaike information criterion of 213, an adjusted R 2 value of 0.78, and a concordance index of 0.82 for association with MACE., Conclusion: Echocardiographic parameters of diastolic dysfunction were associated with MACE in this population study, in combination with the severity of left ventricular hypertrophy and genetic variation. Left atrial size parameters adjusted for body surface area were independently associated with adverse events. Additional study of diastolic function parameters adjusted for patient size could facilitate the prediction of adverse events in pediatric patients with HCM., Competing Interests: Conflicts of Interest None., (Copyright © 2023 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)

Recent studies in adults suggested that extended-interval dosing of rituximab/ocrelizumab (RTX/OCR) larger than 12 months was safe and could improve safety. This was an observational cohort study of very active pediatric-onset multiple sclerosis (PoMS) (median (range) age, 16 (12-17) years) treated with RTX/OCR with 6 month standard-interval dosing ( n = 9) or early extended-interval dosing ( n = 12, median (range) interval 18 months (12-25)). Within a median (range) follow-up of 31 (12-63) months after RTX/OCR onset, one patient (standard-interval) experienced relapse and no patient showed disability worsening or new T2-weighted lesions. This study suggests that the effectiveness of RTX/OCR is maintained with a median extended-interval dosing of 18 months in patients with very active PoMS., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Although contemporary outcomes of initial surgical repair of tetralogy of Fallot (TOF) are excellent, the survival of adult patients remains significantly lower than that of the normal population due to the high incidence of heart failure, ventricular arrhythmias, and sudden cardiac death. The underlying mechanisms are only partially understood but involve an adverse biventricular response, so-called remodelling, to key stressors such as right ventricular (RV) pressure-and/or volume-overload, myocardial fibrosis, and electro-mechanical dyssynchrony. In this review, we explore risk factors and mechanisms of biventricular remodelling, from histological to electro-mechanical aspects, and the role of imaging in their assessment. We discuss unsolved challenges and future directions to better understand and treat the long-term sequelae of this complex congenital heart disease., (Copyright © 2024. Published by Elsevier Inc.)

Background: Diastolic myocardial stiffness (MS) can serve as a key diagnostic parameter for congenital or acquired heart diseases. Using shear modulus and shear-wave velocity (SWV), shear-wave elastography (SWE) is an emerging ultrasound-based technique that can allow noninvasive assessment of MS. However, MS extrinsic parameters such as left ventricular geometric characteristics could affect shear-wave propagation. The aims of this study were to determine a range of normal values of MS using SWE in age groups of healthy children and young adults and to explore the impact of left ventricular geometric characteristics on SWE., Methods: Sixty healthy volunteers were recruited in the study and divided into 2 groups: neonates (0-1 months old, n = 15) and >1 month old (1 month to 45 years of age, n = 45). SWE was performed using the Verasonics Vantage systems with a phased-array ultrasound probe. The anteroseptal basal segment was assessed in two views. SWE was electrocardiographically triggered during the end-diastolic phase. Conventional echocardiography was performed to assess ventricular function and anatomy. Results are presented as stiffness values along with mean velocity measurements and SDs. Simple and multivariate linear regression analyses were performed., Results: For neonates, mean MS was 1.87 ± 0.79 kPa (range, 0.59-2.91 kPa; mean SWV, 1.37 ± 0.57 m/sec), with high variability and no correlation with age (P = .239). For this age group, no statistically significant correlation was found between MS and any demographic or echocardiographic parameters (P > .05). For the >1 month old group, a mean MS value of 1.67 ± 0.53 kPa was observed (range, 0.6-3 kPa; mean SWV, 1.29 ± 0.49 m/sec) for healthy volunteers. When paired for age, no sex-related difference was observed (P = .55). In univariate linear regression analysis, age (r = 0.83, P < .01), diastolic interventricular septal thickness (r = 0.72, P < .01), and left ventricular end-diastolic diameter (r = 0.67, P < .01) were the parameters with the highest correlation coefficients with MS. In a multiple linear regression analysis incorporating these three parameters as cofounding factors, age was the only statistically significant parameters (r = 0.81, P = .02)., Conclusion: Diastolic MS increases linearly in children and young adults. Diastolic MS correlates more robustly with age than with myocardial and left ventricular geometric characteristics. However, the geometry affects SWV, implying the need to determine well-established boundaries in future studies for the clinical application of SWE., (Copyright © 2023 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)

Background: There is conflicting literature regarding the long-term effect of anthracycline treatment on arterial stiffness. This study assessed local arterial stiffness using ultrafast ultrasound imaging (UUI) in anthracycline treated childhood cancer survivors, at rest and during exercise., Methods: 20 childhood cancer survivors (mean age 21.02 ± 9.45 years) treated with anthracyclines (mean cumulative dose 200.7 ± 126.80 mg/m 2 ) and 21 healthy controls (mean age 26.00 ± 8.91 years) were included. Participants completed a demographic survey, fasting bloodwork for cardiovascular biomarkers, and performed a submaximal exercise test on a semi-supine bicycle. Pulse wave velocity (PWV) was measured in the left common carotid artery by direct pulse wave imaging using UUI at rest and submaximal exercise. Both PWV at the systolic foot (PWV-SF) and dicrotic notch (PWV-DN) were measured. Central (carotid-femoral) PWV was obtained by applanation tonometry. Carotid measurements were taken by conventional ultrasound. Measures were compared using two-tailed Students t -test or Chi-squared test, as appropriate., Results: There was no statistically significant difference ( p  > 0.05) between childhood cancer survivors and healthy controls in demographic parameters (age, sex, weight, height, BMI), blood biomarkers (total cholesterol, triglycerides, LDL-c, HDL-c, hs-CRP, fasting glucose, insulin, Hb A1c), cardiovascular parameters (intima media thickness, systolic and diastolic blood pressure, heart rate, carotid diameters, distensibility) or PWV measured by UUI at rest or at exercise. There was also no difference in the cardiovascular adaptation between rest and exercise in the two groups ( p  > 0.05). Multivariate analysis revealed age ( p  = 0.024) and LDL-c ( p  = 0.019) to be significant correlates of PWV-SF in childhood cancer survivors, in line with previously published data., Conclusion: We did not identify a significant impact of anthracycline treatment in young survivors of childhood cancer on local arterial stiffness in the left common carotid artery as measured by UUI., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Rasouli, Baranger, Slorach, Hui, Venet, Nguyen, Henry, Gopaul, Nathan, Mertens and Villemain.)

Sepsis-acquired immunosuppression may play a major role in patients' prognosis through increased risk of secondary infections. Triggering receptor expressed on myeloid cells 1 (TREM-1) is an innate immune receptor involved in cellular activation. Its soluble form (sTREM-1) has been described as a robust marker of mortality in sepsis. The objective of this study was to evaluate its association with the occurrence of nosocomial infections alone or in combination with human leucocyte antigen-DR on monocytes (mHLA-DR)., Design: Observational study., Setting: University Hospital in France., Patients: One hundred sixteen adult septic shock patients as a post hoc study from the IMMUNOSEPSIS cohort (NCT04067674)., Interventions: None., Measurements and Main Results: Plasma sTREM-1 and monocyte HLA-DR were measured at day 1 or 2 (D1/D2), D3/D4, and D6/D8 after admission. Associations with nosocomial infection were evaluated through multivariable analyses. At D6/D8, both markers were combined, and association with increased risk of nosocomial infection was evaluated in the subgroup of patients with most deregulated markers in a multivariable analysis with death as a competing risk. Significantly decreased mHLA-DR at D6/D8 and increased sTREM-1 concentrations were measured at all time points in nonsurvivors compared with survivors. Decreased mHLA-DR at D6/D8 was significantly associated with increased risk of secondary infections after adjustment for clinical parameters with a subdistribution hazard ratio of 3.61 (95% CI, 1.39-9.34; p = 0.008). At D6/D8, patients with persistently high sTREM-1 and decreased mHLA-DR presented with a significantly increased risk of infection (60%) compared with other patients (15.7%). This association remained significant in the multivariable model (subdistribution hazard ratio [95% CI], 4.65 [1.98-10.9]; p < 0.001)., Conclusions: In addition to its prognostic interest on mortality, sTREM-1, when combined with mHLA-DR, may help to better identify immunosuppressed patients at risk of nosocomial infections., Competing Interests: Drs. Derive and Jolly are employed by Inotrem. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the Society of Critical Care Medicine.)

Type I and III interferons (IFN-I/λ) are important antiviral mediators against SARS-CoV-2 infection. Here, we demonstrate that plasmacytoid dendritic cells (pDC) are the predominant IFN-I/λ source following their sensing of SARS-CoV-2-infected cells. Mechanistically, this short-range sensing by pDCs requires sustained integrin-mediated cell adhesion with infected cells. In turn, pDCs restrict viral spread by an IFN-I/λ response directed toward SARS-CoV-2-infected cells. This specialized function enables pDCs to efficiently turn-off viral replication, likely via a local response at the contact site with infected cells. By exploring the pDC response in SARS-CoV-2 patients, we further demonstrate that pDC responsiveness inversely correlates with the severity of the disease. The pDC response is particularly impaired in severe COVID-19 patients. Overall, we propose that pDC activation is essential to control SARS-CoV-2-infection. Failure to develop this response could be important to understand severe cases of COVID-19., (© 2023. The Author(s).)

Dendritic cells (DCs) are key regulators of both innate and adaptive immunity via varied functions, including cytokine production and antigen presentation. Plasmacytoid DC (pDC) is a DC subset specialized in the production of type I and III interferons (IFNs). They are thus pivotal players of the host antiviral response during the acute phase of infection by genetically distant viruses. The pDC response is primarily triggered by the endolysosomal sensors Toll-like receptors, which recognize nucleic acids from pathogens. In some pathologic contexts, pDC response can also be triggered by host nucleic acids, hereby contributing to the pathogenesis of autoimmune diseases, such as, e.g., systemic lupus erythematosus. Importantly, recent in vitro studies from our laboratory and others uncovered that pDCs sense viral infections when a physical contact is established with infected cells. This specialized synapse-like feature enables a robust type I and III IFN secretion at the infected site. Therefore, this concentrated and confined response likely limits the correlated deleterious impacts of excessive cytokine production to the host, notably due to tissue damages. Here we provide a pipeline of methods for ex vivo studies of pDC antiviral functions, designed to address how pDC activation is regulated by cell-cell contact with virally infected cells and the current approaches enabling to decipher the underlying molecular events leading to an efficient antiviral response., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)