Clusterization-Triggered Emission Enhanced by Energy Transfer in the Layered Metal Halide Hybrid Material (TET)2[Pb4Cl16].

Clusterization-triggered emission (CTE) of nonconventional chromophores has recently attracted increased interest for its synergetic photophysical properties and promising applications, such as optical anticounterfeiting, white-light emission devices, or molecular sensing. Many studies have been conducted on pure organic clusteroluminogens (CLgens), but very few have explored organic-inorganic hybrid (OIH) materials. This work deals with optical properties of a new OIH compound (TET)2[Pb4Cl16] (TET = N,N'-bis(2-aminoethyl)-1,3-propanediamine (C7N4H24)), which presents an unprecedented two-dimensional perovskitoid structure formed by strongly distorted [Pb4Cl16] layers of corner and edge-sharing [PbCl6] octahedra, separated by TET tetra-ammonium cations. Under UV-visible excitations, (TET)2[Pb4Cl16] exhibits white-light emission, tunable excitation-wavelength-dependent emission, and green afterglow room temperature phosphorescence (RTP) lasting for more than 0.63 s, all of which are direct signatures of CTE. The optical interpretations are supported by density functional theory (DFT) calculations of the band structure. Two mechanisms are involved in the emission process: resonant energy transfer (RET) between the organic and the inorganic components, and clusteroluminescence (CL) governed by a rigid conformation of the organic cations and extended electron delocalization over supramolecular organic clusters confined within the interlayer spacing. The different features of CLgens in (TET)2[Pb4Cl16] are discussed, and the role of the organic nonconjugated molecule in the emission process is emphasized.

[Virological diagnosis of lower respiratory tract infections]. / Diagnostic virologique des infections respiratoires basses.

INTRODUCTION: The etiological diagnosis of bronchopulmonary infections cannot be assessed with clinical, radiological and epidemiological data alone. Viruses have been demonstrated to cause a large proportion of these infections, both in children and adults. BACKGROUND: The diagnosis of viral bronchopulmonary infections is based on the analysis of secretions, collected from the lower respiratory tract when possible, by techniques that detect either influenza and respiratory syncytial viruses, or a large panel of viruses that can be responsible for respiratory disease. The latter, called multiplex PCR assays, allow a syndromic approach to respiratory infection. Their high cost for the laboratory raises the question of their place in the management of patients in terms of antibiotic economy and isolation. In the absence of clear recommendations, the strategy and equipment are very unevenly distributed in France. OUTLOOK: Medico-economic analyses need to be performed in France to evaluate the place of these tests in the management of patients. The evaluation of the role of the different viruses often detected in co-infection, especially in children, also deserves the attention of virologists and clinicians. CONCLUSIONS: The availability of new diagnostic technologies, the recent emergence of SARS-CoV-2, together with the availability of new antiviral drugs are likely to impact future recommendations for the management of viral bronchopulmonary infections.

COVID-19 outpatient management: Shorter time to recovery in Healthcare workers according to an electronic daily symptoms assessment.

OBJECTIVES: Our aim is to compare the course of the disease between healthcare workers (HCWs) and non-HCWs suffering from covid-19 and eligible for outpatient management. METHODS: Single-center prospective cohort of outpatients with covid-19, diagnosed between the 10th March and the 2nd April, 2020 with a daily collection of symptoms by an on-line auto-questionnaire. RESULTS: A total of 186 patients were included (median age, 41 years [interquartile range, 19-78 years]; 74.2% female), of whom 132 (71%) were HCWs. The median follow-up after symptom onset was 14 (min 4-max 24) days. HCWs were significantly younger than non-HCWs (median age 40.3 years vs. 47.2 years [P<0.005]), and 81.8% were women. Four patients (2.2%) were hospitalized including one HCW. The median time to recovery was 9 days after symptom onset (95% CI 8-11) in the global population and respectively 8 (95% CI 8-9) and 13 (95% CI 11-15) days in HCWs and in non-HCWs (P<0.005). After adjusting for age, co-morbidities, and gender, the instantaneous risk ratio for symptom absence in HCWs was 1.76 compared with non-HCWs (95% CI [1.16-2.67], P=0.037). CONCLUSION: HCWs suffering from covid-19 had favorable outcomes and had a shorter time to recovery than non HCWs.

SARS-CoV-2 infection: advocacy for training and social distancing in healthcare settings.

This article reports the observed rate of infection with severe acute respiratory syndrome coronavirus-2 in healthcare workers (HCWs) who worked on wards dedicated to care of patients with coronavirus disease 2019 (COVID-19) compared with HCWs who worked on non-COVID-19 wards. The infection rate was significantly higher among HCWs who worked on non-COVID-19 wards (odds ratio 2.3, P=0.005), illustrating the need to strengthen social distancing measures and training.

Impact of bedside diagnosis of influenza in the paediatric emergency ward.

OBJECTIVES: This prospective study performed in the paediatric emergency department of the University Hospital of Saint-Etienne aimed to measure the impact of the 24/7 bedside use of the Veritor™ System (Becton Dickinson) on the reduction of supplementary investigations, hospital stay and antimicrobial use. METHODS: Influenza virus A and B antigens were detected with a rapid influenza digital immunoassay (DIA) on nasopharyngeal aspirates (NPAs) sampled from the children consulting at the paediatric emergency department between January and March 2016 for influenza-like illness. The same NPA was tested by immunofluorescence and/or molecular routine assays. Before performing the DIA, the clinician filled in a questionnaire listing the tests that he/she would have prescribed in the absence of the rapid testing. The prescription of complementary investigations, antimicrobial treatments and hospital stay were also compared to those of the 3 previous years. RESULTS: A total of 514 children with flu-like symptoms were included. The use of the DIA at bedside decreased the prescription of blood puncture by 47.9% (21.2% to 6.6%), of chest X-rays by 69.0% (33.3% to 10.3%), of lumbar puncture by 77.8% (7.0% to 1.6%), of urine culture by 79.2% (23.3% to 4.9%), of antibiotic treatments by 70.1% (16.9% to 5.1%), and of hospital stay by 25.0% (27.2% to 20.4%), resulting in a reduction of medical costs estimated to more than €69 000 in a season. CONCLUSIONS: In addition to delivering a rapid aetiological diagnosis, this strategy saves medical costs and favours an antimicrobial stewardship strategy. However, further prospective studies are needed to confirm our findings.

Predominance of G9P[8] rotavirus strains throughout France, 2014-2017.

OBJECTIVES: Group A rotavirus is a major cause of acute gastroenteritis in young children worldwide. A prospective surveillance network has been set up in France to investigate rotavirus infections and to detect the emergence of potentially epidemic strains. METHODS: From 2014 to 2017, rotavirus-positive stool samples were collected from 2394 children under 5 years old attending the paediatric emergency units of 13 large hospitals. Rotaviruses were genotyped by RT-PCR with regard to their outer capsid proteins VP4 and VP7. RESULTS: Genotyping of 2421 rotaviruses showed that after a marked increase in G9P[8] (32.1%) during the 2014-2015 season, G9P[8] became the predominant genotype during the 2015-2016 and 2016-2017 seasons with detection rates of 64.1% and 77.3%, respectively, whereas G1P[8] were detected at low rates of 16.8% and 6.6%, respectively. Phylogenetic analysis of the partial rotavirus VP7 and VP4 coding genes revealed that all of these G9P [8] strains belonged to the lineage III and the P [8]-3 lineage, respectively, and shared the same genetic background (G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1) as did most of previously detected G9P[8] strains and particularly the emerging G9P[8] strains from the 2004-2005 season in France. CONCLUSIONS: G9P[8] rotaviruses have become the predominant circulating genotype for the first time since their emergence a decade ago. In the absence of rotavirus immunization programmes in France, our data give an insight into the natural fluctuation of rotavirus genotypes in a non-vaccinated population and provide a base line for a better interpretation of data in European countries with routine rotavirus vaccination.

Hypoxia inducible factor one alpha and human viral pathogens.

If the oxygen tension level is 21% in ambient air, it is only between 14% and 1% in vivo. Consequently, viral pathogens are exposed and must adapt to these fluctuating oxygen levels to colonize the host and cause diseases. The problem is that for many years, the virological studies have been performed at 21% oxygen levels and consequently this is a real handicap to have a correct view of the mechanistic aspects of human viral infections. In this brief review, we describe for some selected examples the interactions of human viruses with this relative hypoxia observed in vivo.

Clinical severity and molecular characteristics of circulating and emerging rotaviruses in young children attending hospital emergency departments in France.

Group A rotavirus (RVA) is the leading cause of acute gastroenteritis in young children worldwide. A prospective surveillance network has been set up to investigate the virological and clinical features of RVA infections and to detect the emergence of potentially epidemic strains in France. From 2009 to 2014, RVA-positive stool samples were collected from 4800 children <5 years old attending the paediatric emergency units of 16 large hospitals. Rotaviruses were then genotyped by RT-PCR with regard to their outer capsid proteins VP4 and VP7. Genotyping of 4708 RVA showed that G1P[8] strains (62.2%) were predominant. The incidence of G9P[8] (11.5%), G3P[8] (10.4%) and G2P[4] (6.6%) strains varied considerably, whereas G4P[8] (2.7%) strains were circulating mostly locally. Of note, G12P[8] (1.6%) strains emerged during the seasons 2011-12 and 2012-13 with 4.1% and 3.0% prevalence, respectively. Overall, 40 possible zoonotic reassortants, such as G6 (33.3%) and G8 (15.4%) strains, were detected, and were mostly associated with P[6] (67.5%). Analysis of clinical records of 624 hospitalized children and severity scores from 282 of them showed no difference in clinical manifestations or severity in relation to the genotype. The relative stability of RVA genotypes currently co-circulating and the large predominance of P[8] type strains may ensure vaccine effectiveness in France. The surveillance will continue to monitor the emergence of new reassortants that might not respond to current vaccines, all the more so as all genotypes can cause severe infections in infants.

Contamination of healthcare workers' mobile phones by epidemic viruses.

Mobile phones (MPs) are potential reservoirs of nosocomial bacteria, but few data are available concerning viruses. We aimed to evaluate the presence of virus RNA from epidemic viruses including metapneumovirus, respiratory syncytial virus, influenza viruses, rotavirus (RV) and norovirus on the MPs used by healthcare workers (HCWs) and to relate it to hygiene measures. An anonymous behavioural questionnaire about MP use at hospital was administered to the HCWs of four adult and paediatric departments of a university hospital. After sampling personal (PMP) and/or professional MPs (digital enhanced cordless telephone, DECT), virus RNAs were extracted and amplified by one-step real-time reverse transcription-quantitative PCR. The molecular results were analysed in a masked manner in relation to the behavioural survey. Questionnaires from 114 HCWs (25 [corrected] senior physicians, 30 residents, 32 nurses, 27 nurses' assistants) working either in adult (n = 58) or paediatric (n = 56) departments were analysed. Medical personnel used their PMP more frequently than paramedical HCWs (33/65 vs. 10/59, p <0.001). MPs were used during care more frequently in adult wards than in paediatric ones (46/58 vs. 27/56, p <0.001). Virus RNA was detected on 42/109 (38.5%) collected MPs, with RV found on 39, respiratory syncytial virus on three and metapneumovirus on one. The presence of virus RNA was significantly associated with MPs from the paediatric HCWs (p <0.001). MPs routinely used in hospital, even during care, can host virus RNA, especially RV. Promotion of frequent hand hygiene before and after MP use, along with frequent cleaning of MPs, should be encouraged.

Structural phase transition causing anomalous photoluminescence behavior in perovskite (C6H11NH3)2[PbI4].

Optical and structural properties of the organic-inorganic hybrid perovskite-type (C6H11NH3)2[PbI4] (abbreviated as C6PbI4) were investigated using optical absorption, photoluminescence (PL), and x-ray diffraction measurements. Room temperature, optical absorption measurements, performed on spin-coated films of C6PbI4, revealed two absorption bands at 2.44 and 3.21 eV. Upon 325 nm (3.815 eV) laser irradiation, strong green PL emission peaks were observed at 2.41 eV (P1) and 2.24 eV (P2) and assigned to free and localized excitons, respectively. The exciton binding energy was estimated at 356 meV. At low temperature, two additional emission bands were detected at 2.366 eV (P3) and a large band (LB) at 1.97 eV. The former appeared only below 40 K and the latter emerged below 130 K. The thermal dependence of the PL spectra revealed an abnormal behavior accompanied by singularities in the peak positions and intensities at 40 and 130 K. X-ray diffraction studies performed on powder and single crystals as a function of temperature evidenced significant changes of the interlayer spacing at 50 K and ∼138 K. Around 138 K, a commensurate to incommensurate structural phase transition occurred on cooling. It involves a symmetry breaking leading to a distortion of the PbI6 octahedron. The resulting incommensurate spatial modulation of the Pb-I distances (and Pb-I-Pb angles) causes a spatial modulation of the band gap, which is at the origin of the emergence of the LB below ∼130 K and the anomalous behavior of the position of P1 below 130 K. The change of the interlayer spacing in the 40-50 K range may in turn be related to the significant decrease of the intensity of P2 and the maximum emission of the LB. These results underline the intricate character of the structural and the PL properties of the hybrid perovskites; understanding such properties should benefit to the design of optoelectronic devices with targeted properties.

Plant-derived H7 VLP vaccine elicits protective immune response against H7N9 influenza virus in mice and ferrets.

In March 2013, the Chinese Centre for Disease Control and Prevention confirmed the first reported case of human infection with an avian influenza A H7N9 virus. Infection with this virus often caused severe pneumonia and acute respiratory distress syndrome resulting in a case fatality rate >35%. The risk of pandemic highlighted, once again, the need for a more rapid and scalable vaccine response capability. Here, we describe the rapid (19 days) development of a plant-derived VLP vaccine based on the hemagglutinin sequence of influenza H7N9 A/Hangzhou/1/2013. The immunogenicity of the H7 VLP vaccine was assessed in mice and ferrets after one or two intramuscular dose(s) with and without adjuvant (alum or GLA-SE™). In ferrets, we also measured H7-specific cell-mediated immunity. The mice and ferrets were then challenged with H7N9 A/Anhui/1/2013 influenza virus. A single immunization with the adjuvanted vaccine elicited a strong humoral response and protected mice against an otherwise lethal challenge. Two doses of unadjuvanted vaccine significantly increased humoral response and resulted in 100% protection with significant reduction of clinical signs leading to nearly asymptomatic infections. In ferrets, a single immunization with the alum-adjuvanted H7 VLP vaccine induced strong humoral and CMI responses with antigen-specific activation of CD3(+) T cells. Compared to animals injected with placebo, ferrets vaccinated with alum-adjuvanted vaccine displayed no weight loss during the challenge. Moreover, the vaccination significantly reduced the viral load in lungs and nasal washes 3 days after the infection. This candidate plant-made H7 vaccine therefore induced protective responses after either one adjuvanted or two unadjuvanted doses. Studies are currently ongoing to better characterize the immune response elicited by the plant-derived VLP vaccines. Regardless, these data are very promising for the rapid production of an immunogenic and protective vaccine against this potentially pandemic virus.

First evidence of light-induced spin transition in molybdenum(IV).

Photo-induced spin transition in a molybdenum-zinc complex has been evidenced and fully characterized by Squid magnetometry and several spectroscopies performed under irradiation (IR, EPR, etc.). The phenomenon has been confirmed by X-ray diffraction and DFT calculations yielding a Light-Induced Excited Spin State Trapping Effect (LIESST) on a 4d transition metal ion.

First identification of the herpes simplex virus by skin-dedicated ex vivo fluorescence confocal microscopy during herpetic skin infections.

BACKGROUND: Skin-dedicated ex vivo fluorescence confocal microscopy (FCM) has so far been used to identify cutaneous tumours on freshly excised samples using acridine orange as fluorochrome. AIM: To use FCM for a new indication, namely, the identification of the herpes simplex virus (HSV) in skin lesions, using fluorescent antibodies. METHODS: Six roof samples from skin vesicles suspicious for HSV lesions were incubated with anti-HSV-1 and anti-HSV-2 antibodies coupled with fluorescein isothiocyanate, and examined under skin-dedicated ex vivo FCM. The positive controls were swabs taken from the floor of each vesicle and observed under conventional direct fluorescence assay (DFA) and by viral cultures. Roof samples from three bullae of bullous pemphigoid were the negative controls. RESULTS: Using ex vivo FCM, the samples from the lesions clinically suspicious for HSV infection were seen to be fluorescent after incubation with anti-HSV-1, and were negative after incubation with anti-HSV-2 antibodies. Conventional DFA with an optical microscope and cultures confirmed the presence of HSV-1 infection. CONCLUSIONS: By using fluorescent antibodies to identify precise structures, ex vivo FCM can be used for indications other than tumour identification. More specifically, it can be an additional diagnostic tool for HSV infection.

The impact of cytomegalovirus reactivation and its treatment on the course of inflammatory bowel disease.

BACKGROUND: Consequences of latent cytomegalovirus (CMV) infection reactivation on inflammatory bowel disease (IBD) flare, as a flare-worsening factor or simple bystander, are debated. Impact of anti-viral treatment on IBD course is poorly known. AIM: To assess the impact of CMV reactivation on patients hospitalised for IBD flare and the effect of anti-viral treatment on IBD flare in patients with CMV reactivation. METHODS: First, a population of UC patients from Saint-Antoine hospital, in flare with positive blood CMV PCR without anti-viral treatment (n = 26), were compared to matched patients with negative blood CMV PCR in a case-control study. Secondly, a total of 110 hospitalisations between October 2003 and May 2012 for IBD flare-up with CMV reactivation (80 diagnosed on blood PCR, 33 on tissue PCR) were identified in three French referral centres. Evolution following CMV reactivation diagnosis was compared between patients receiving anti-viral treatment and those who did not. RESULTS: In the case-control study, no differences were observed between the two groups regarding length of hospital stay and colectomy rate. Comparing treated and untreated patients, no differences were observed at inclusion regarding age, gender, IBD type, immunosuppressant, CRP and haemoglobin level. No differences were observed regarding CRP level decrease at 10 days and colectomy rate at 3 months. Anti-viral treatment was associated with lower serum albumin level at inclusion and longer hospitalisation. CONCLUSIONS: CMV reactivation does not appear to alter the course of IBD flare. CMV treatment does not seem to impact the course of IBD. These results should be confirmed prospectively.