Lung abscess following ventilator-associated pneumonia during COVID-19: a retrospective multicenter cohort study.

BACKGROUND: Patients undergoing mechanical ventilation (MV) for COVID-19 exhibit an increased risk of ventilator-associated pneumonia (VAP). The occurrence of lung abscesses following VAP in these patients has been poorly studied. We aimed to describe the incidence, characteristics, risk factors and prognosis of lung abscesses complicating VAP after COVID-19. METHODS: We conducted an observational, retrospective study in three French intensive care units. Patients admitted for acute respiratory failure with a confirmed SARS-CoV-2 PCR and requiring MV for more than 48 h were included. RESULTS: Among the 507 patients included, 326 (64%) had a documented VAP. Of these, 23 (7%) developed a lung abscess. Enterobacterales (15/23, 65%) were the main documentation, followed by non-fermenting Gram-negative bacilli (10/23, 43%) and Gram-positive cocci (8/23, 35%). Lung abscesses were mainly plurimicrobial (15/23, 65%). In multivariate analysis, a plurimicrobial 1st VAP episode (OR (95% CI) 2.93 (1.16-7.51); p = 0.02) and the use of hydrocortisone (OR (95% CI) 4.86 (1.95-12.1); p = 0.001) were associated with lung abscess development. Intensive care unit (ICU) mortality of patients with lung abscesses reached 52%, but was not significantly higher than for patients with VAP but no lung abscess. Patients with lung abscesses had reduced ventilator-free days at day 60, a longer duration of MV and ICU stay than patients with VAP but no lung abscess (respectively, 0 (0-3) vs. 16 (0-42) days; p < 0.001, 49 (32-73) vs. 25 (11-41) days; p < 0.001, 52 (36-77) vs. 28 (16-47) days; p < 0.001). CONCLUSIONS: Lung abscessing pneumonia is not uncommon among COVID-19 patients developing VAP. A plurimicrobial first VAP episode and the use of hydrocortisone are independently associated with this complication. In COVID-19 patients with persistent VAP, a chest CT scan investigating the evolution toward lung abscess should be considered.

Influence of salivary acquired pellicle on colour changes and minerals content of dentine after application of silver diamine fluoride followed by potassium iodide.

PURPOSE: This study evaluated whether the presence of the salivary acquired pellicle (AP) had any effect on the dentin's darkening and on the caries arresting effect after the use of SDF + KI, in a cariogenic challenge. METHODS: Human dentin specimens were standardised, submitted to artificial caries lesion formation, and divided into five groups (n = 20): C: control group-no treatment, SDF: 38% SDF, APSDF: SDF 38% and AP, KISDF: 38% SDF and KI, and APKISDF: 38% SDF, KI and AP, that were submitted to pH cycling. Colour evaluation (CIE L*a*b* system) and surface hardness were performed before and after the treatments/pH cycling. RESULTS: SDF and APSDF groups showed no difference in colour. KISDF and APKISDF groups showed significantly different colours than the groups without KI. SDF, APSDF, and APKISDF groups had less mineral loss than C and KISDF. SDF, APSDF, and APKISDF revealed significantly greater mineral recovery, compared to KISDF and C. CONCLUSION: The AP did not influence the dentin´s colour after SDF + KI, but had a protective role in modulating the dentin´s mineral gain/loss. KI used after SDF decreased the dentin´s darkening, and did not interfere with the dentin de/remineralization process.

Wannier excitons confined in hexagonal boron nitride triangular quantum dots.

With the ever-growing interest in quantum computing, understanding the behavior of excitons in monolayer quantum dots has become a topic of great relevance. In this paper, we consider a Wannier exciton confined in a triangular quantum dot of hexagonal boron nitride. We begin by outlining the adequate basis functions to describe a particle in a triangular enclosure, analyzing their degeneracy and symmetries. Afterwards, we discuss the excitonic Hamiltonian inside the quantum dot and study the influence of the quantum dot dimensions on the excitonic states.

Excitonic instability in transition metal dichalcogenides.

When transition-metal dichalcogenide monolayers lack inversion symmetry, their low-energy single particle spectrum near some high-symmetry points can, in some cases, be described by tilted massive Dirac Hamiltonians. The so-called Janus materials fall into that category. Inversion symmetry can also be broken by the application of out-of-plane electric fields, or by the mere presence of a substrate. Here we explore the properties of excitons in TMDC monolayers lacking inversion symmetry. We find that exciton binding energies can be larger than the electronic band gap, making such materials promising candidates to host the elusive exciton insulator phase. We also investigate the excitonic contribution to their optical conductivity and discuss the associated optical selection rules.

Laser induced enhanced coupling between photons and squeezed magnons in antiferromagnets.

In this paper we consider a honeycomb antiferromagnet subject to an external laser field. Obtaining a time-independent effective Hamiltonian, we find that the external laser renormalizes the exchange interaction between the in-plane components of the spin-operators, and induces a synthetic Dzyaloshinskii-Moria interaction (DMI) between second neighbors. The former allows the control of the magnon dispersion's bandwidth and the latter breaks time-reversal symmetry inducing non-reciprocity in momentum space. The eigen-excitations of the system correspond to squeezed magnons whose squeezing parameters depend on the properties of the laser. When studying how these spin excitations couple with cavity photons, we obtain a coupling strength which can be enhanced by an order of magnitude via careful tuning of the laser's intensity, when compared to the case where the laser is absent. The transmission plots through the cavity are presented, allowing the mapping of the magnons' dispersion relation.

Enhancing the hybridization of plasmons in graphene with 2D superconductor collective modes.

We explore ways in which the close proximity between graphene sheets and monolayers of 2D superconductors can lead to hybridization between their collective excitations. We consider heterostructures formed by combinations of graphene sheets and 2D superconductor monolayers. The broad range of energies in which the graphene plasmon can exist, together with its tunability, makes such heterostructures promising platforms for probing the many-body physics of superconductors. We show that the hybridization between the graphene plasmon and the Bardasis-Schrieffer mode of a 2D superconductor results in clear signatures on the near-field reflection coefficient of the heterostructure, which in principle can be observed in scanning near-field microscopy experiments.

Fungal and bacterial coinfections increase mortality of severely ill COVID-19 patients.

BACKGROUND: SARS-CoV-2 predisposes patients to secondary infections; however, a better understanding of the impact of coinfections on the outcome of hospitalized COVID-19 patients is still necessary. AIM: To analyse death risk due to coinfections in COVID-19 patients. METHODS: The odds of death of 212 severely ill COVID-19 patients were evaluated, with detailed focus on the risks for each pathogen, site of infection, comorbidities and length of hospitalization. FINDINGS: The mortality rate was 50.47%. Fungal and/or bacterial isolation occurred in 89 patients, of whom 83.14% died. Coinfected patients stayed hospitalized longer and had an increased odds of dying (odds ratio (OR): 13.45; R2 = 0.31). The risk of death was increased by bacterial (OR: 11.28) and fungal (OR: 5.97) coinfections, with increased levels of creatinine, leucocytes, urea and C-reactive protein. Coinfections increased the risk of death if patients suffered from cardiovascular disease (OR: 11.53), diabetes (OR: 6.00) or obesity (OR: 5.60) in comparison with patients with these comorbidities but without pathogen isolation. The increased risk of death was detected for coagulase-negative Staphylococcus (OR: 25.39), Candida non-albicans (OR: 11.12), S. aureus (OR: 10.72), Acinetobacter spp. (OR: 6.88), Pseudomonas spp. (OR: 4.77), and C. albicans (OR: 3.97). The high-risk sites of infection were blood, tracheal aspirate, and urine. Patients with coinfection undergoing invasive mechanical ventilation were 3.8 times more likely to die than those without positive cultures. CONCLUSION: Severe COVID-19 patients with secondary coinfections required longer hospitalization and had higher risk of death. The early diagnosis of coinfections is essential to identify high-risk patients and to determine the right interventions to reduce mortality.

Harnessing ultraconfined graphene plasmons to probe the electrodynamics of superconductors.

We show that the Higgs mode of a superconductor, which is usually challenging to observe by far-field optics, can be made clearly visible using near-field optics by harnessing ultraconfined graphene plasmons. As near-field sources we investigate two examples: graphene plasmons and quantum emitters. In both cases the coupling to the Higgs mode is clearly visible. In the case of the graphene plasmons, the coupling is signaled by a clear anticrossing stemming from the interaction of graphene plasmons with the Higgs mode of the superconductor. In the case of the quantum emitters, the Higgs mode is observable through the Purcell effect. When combining the superconductor, graphene, and the quantum emitters, a number of experimental knobs become available for unveiling and studying the electrodynamics of superconductors.

Optical absorption of single-layer hexagonal boron nitride in the ultraviolet.

In this paper we theoretically describe the absorption of hexagonal boron nitride (hBN) single layer. We develop the necessary formalism and present an efficient method for solving the Wannier equation for excitons. We give predictions for the absorption of hBN on quartz and on graphite. We compare our predictions with recently published results (Elias et al 2019 Nat. Commun. 10 2639) for a monolayer of hBN on graphite. The spontaneous radiative lifetime of excitons in hBN is also computed. We argue that the optical properties of hBN in the ultraviolet are very useful for the study of peptides and other biomolecules.

Potential Impact of Populations Drift on Botrytis Occurrence and Resistance to Multi- and Single-Site Fungicides in Florida Southern Highbush Blueberry Fields.

Incidence of blossom blight and Botrytis fruit rot (BFR), caused by Botrytis cinerea, on two southern highbush blueberry cultivars was evaluated in several blueberry fields grown in the vicinity (BB-Str(+)) or not (BB-Str(-)) of strawberry fields in central Florida. Blossom blight and BFR incidence were higher in BB-Str(+) fields in 2014 and significantly higher in 2015 compared to BB-Str(-) fields. In total, 613 B. cinerea isolates (i.e., 181 and 432 isolates from BB-Str(-) and BB-Str(+) fields, respectively) were collected. The isolates were evaluated for sensitivity to eight single-site and one multisite fungicides using a spore germination and a germ tube elongation assay. Overall, 5, 15, 24, 28, 54, and 93% of isolates collected from BB-Str(-) were resistant to penthiopyrad, cyprodinil, boscalid, fenhexamid, pyraclostrobin, and thiophanate-methyl, respectively. Respective resistance frequencies in BB-Str(+) isolates were 10, 30, 65, 66, 89, and 99%. Resistance frequencies for all fungicides were always higher in BB-Str(+) fields compared to BB-Str(-) fields. Isolates exhibiting resistance to six or five fungicides simultaneously were predominant (50 to 70%) in blueberry fields regardless if they were grown in the vicinity of strawberry fields or not. Among 308 and 305 B. cinerea isolates tested in 2014 and 2015, 41.8 and 47.1%, respectively, showed reduced sensitivity to the multisite fungicide captan. The lower label rate of captan applied preventively did not control isolates with reduced sensitivity on detached blueberry fruit. These findings suggest a potential population flow between strawberry and blueberry fields that may impact blossom blight and gray mold development in blueberry fields. The relatively lower fungicide input applied to blueberry fields compared with strawberry fields seems to be sufficient to select for resistance and multiple-resistant phenotypes in B. cinerea populations in blueberry.

[Systemic sclerosis and occupational difficulties: Results of a prospective study]. / Sclérodermie systémique et difficultés professionnelles : résultats d'une enquête prospective.

Between 9000 and 14000 people have systemic sclerosis (ScS) in France. The work is often affected. Our study aims to assess the frequency of professional difficulties (DP) of scleroderma patients, identify these DP, the symptoms involved and the solutions used. A heteroquestionnaire was offered to scleroderma patients the Lille University Hospital. Data were cross-checked with the clinical database of the National Observatory of scleroderma patients. We used 104 questionnaires of which 84% are women. A total of 62.5%, (95% CI [52.5 to 71.8]) patients had experienced DP related to SSc, 55% reported symptoms worsened at work, 41% lower efficiency and a 19% job loss. Symptoms responsible for their DP were mainly asthenia, Raynaud syndrome, arthralgias and finger ulcerations. Only 40% of patients in difficulty were initiating steps with the county home for disabled people and 45% in informing their doctor at work (MT). The MT information absence was related to a misunderstanding of possible aid in 45% of cases, 57% of patients had not found a solution, 41% of them have lost their jobs and 31% of patients in the cohort experienced a drop in income. The impact of SSc the work is important. The aid job retention devices are under-used due to lack of knowledge of steps to take and the role of MT. Taking into account the symptoms responsible for PD must be improved to participate in this retention.

Graphene field-effect transistor array with integrated electrolytic gates scaled to 200 mm.

Ten years have passed since the beginning of graphene research. In this period we have witnessed breakthroughs both in fundamental and applied research. However, the development of graphene devices for mass production has not yet reached the same level of progress. The architecture of graphene field-effect transistors (FET) has not significantly changed, and the integration of devices at the wafer scale has generally not been sought. Currently, whenever an electrolyte-gated FET (EGFET) is used, an external, cumbersome, out-of-plane gate electrode is required. Here, an alternative architecture for graphene EGFET is presented. In this architecture, source, drain, and gate are in the same plane, eliminating the need for an external gate electrode and the use of an additional reservoir to confine the electrolyte inside the transistor active zone. This planar structure with an integrated gate allows for wafer-scale fabrication of high-performance graphene EGFETs, with carrier mobility up to 1800 cm(2) V(-1) s(-1). As a proof-of principle, a chemical sensor was achieved. It is shown that the sensor can discriminate between saline solutions of different concentrations. The proposed architecture will facilitate the mass production of graphene sensors, materializing the potential of previous achievements in fundamental and applied graphene research.

Detection of Colletotrichum acutatum Sensu Lato on Strawberry by Loop-Mediated Isothermal Amplification.

Colletotrichum acutatum, one of the most economically damaging pathogens of strawberry, is the primary causal agent of anthracnose fruit rot (AFR). A key challenge in managing AFR is detecting the pathogen on asymptomatic plants. To meet this need, a loop-mediated isothermal amplification (LAMP) assay was developed that incorporated two sets of primers: LITSG1, targeted on the intergenic transcribed spacer (ITS) region of ribosomal DNA, and Ltub2, on the ß-tubulin 2 gene. In pure culture assays, Ltub2 was specific for detection of C. acutatum, whereas LITSG1 detected C. acutatum and two additional anthracnose pathogens, C. gloeosporioides and C. fragariae. LITSG1 had 10-fold lower detection threshold (20 pg of mycelial DNA) than Ltub2 (200 pg mycelial DNA) in detection of C. acutatum from pure culture. For detection on asymptomatic leaves, two protocols for dislodging C. acutatum for DNA extraction were compared: i) the sonicate-agitate (SA) method and ii) the freeze-incubate-sonicate-agitate (FISA) method, which initially freezes tissues, followed by 2 days of incubation at 26°C in darkness, and then, sonication and agitation. Both methods were used for greenhouse-grown plant leaves that had been spray inoculated with serial dilutions ranging from 1.5 × 106 to 1.5 conidia ml-1. The FISA method produced more repeatable results than the SA method. For the FISA method, detection limits (expressed as initial inoculum concentrations) using LITSG1 and Ltub2 were 1.5 × 101 and 1.5 × 102 conidia ml-1, respectively. For composite samples comprised of inoculated (1.5 × 106 conidia ml-1) and noninoculated leaves of greenhouse-grown strawberry, the two sets of LAMP primers were compared using the SA method. Primer set LITSG1 consistently detected the pathogen from a single inoculated leaf in bulk samples of 50 or fewer pathogen-free leaves, whereas Ltub2 consistently detected one inoculated leaf in 20 or fewer pathogen-free leaves. Using primer set LITSG1, FISA was more sensitive than SA for detecting C. acutatum on leaves of field-grown plants from Florida. In an Iowa field trial using the FISA method, both primer sets detected C. acutatum in samples of asymptomatic leaves 6 days before fruit symptoms appeared. The results indicate that the LAMP assay has potential to provide a simplified method for detection of C. acutatum on asymptomatic strawberry plants.

Analytical solution of electronic transport through a benzene molecule using lattice Green's functions.

Using a Green's function formalism we derive analytical expressions for electronic transmittance through a benzene ring. To motivate the approach we first solve the resonant level system and then extend the method to the benzene case. These results can be used to validate numerical methods.

Optical conductivity of ABA stacked graphene trilayer: mid-IR resonance due to band nesting.

The band structure and the optical conductivity of an ABA (Bernal-type) stacked graphene trilayer are calculated. It is shown that, under appropriate doping, a strong resonant peak develops in the optical conductivity, located at the frequency corresponding to approximately 1.4 times the interlayer hopping energy and caused by the 'nesting' of two nearly parabolic bands in the electronic spectrum. The intensity of this resonant absorption can be controlled by adjusting the gate voltage. The effect is robust with respect to increasing temperature.

La incidencia de márgenes quirúrgicos positivos tras prostatectomía radical asistida por robot: ¿tiene la experiencia del cirujano influencia en todos los estadios patológicos? / Incidence of positive surgical margins after robotic assisted radical prostatectomy: Does the surgeon's experience have an influence on all pathological stages?

Objetivo: Analizar las características clínico-quirúrgicas de 300 pacientes con cáncer de próstata operados con cirugía robótica y el impacto de la experiencia del cirujano en los resultados oncológicos. Material y métodos: Se realizó un análisis retrospectivo de 300 prostatectomías radicales asistidas con robot realizadas todas por el mismo cirujano. Se dividieron los pacientes en 3 grupos de 100 en orden cronológico, de acuerdo a fecha de la cirugía. Todos los pacientes presentaban estadio clínico órgano-confinado. Ningún paciente recibió hormonobloqueo neoadyuvante. Se analizan en cada grupo las variables que, a priori, impactarían en la presencia de márgenes quirúrgicos positivos (MQP). Finalmente se subdividió cada grupo en pacientes con enfermedad órgano-confinada y pacientes con enfermedad extraprostática y se analizaron los MQP. Resultados: Los grupos fueron homogéneos entre sí. La incidencia de pT2 y pT3 o más fue similar entre grupos (p = 0,691). La incidencia global de MQP fue del 21%, 28% en el primer grupo, del 20% en el segundo grupo y del 16% en el tercer grupo (p = 0,108). Se observó una tendencia de descenso lineal significativa (p = 0,024). En pacientes pT2 la incidencia global de MQP fue de 16,6%, con un descenso significativo entre los grupos (p = 0,009). La diferencia significativa fue hallada entre el grupo 1 y el grupo 3 (p = 0,004). En pacientes pT3 o más la incidencia global de MQP fue del 27,7% sin evidencia de descenso significativo (p = 0,978). Conclusiones: Hemos encontrado una reducción significativa de los MQP relacionados con la experiencia del cirujano para los pacientes con enfermedad órgano-confinada, y no así para los pacientes pT3

Objective: The aim of this study is to analyze the clinical and surgical features of patients who underwent robotic-assisted radical prostatectomy (RARP) at our institution, and the impact of the surgeon's experience in the oncological results related to pathological stage. Material and methods: An analysis of 300 RARP consecutively performed by the same urologist was conducted. Patients were divided into 3 groups of 100 patients in chronological order, according to surgery date. All patients had organ-confined clinical stage. Variables which could impact in positive margins rates were analyzed. Finally, positive surgical margins (PSM) in regard to pathological stage and surgeon's experience were compared and analyzed. Results: No significant differences were found in variables which could impact in PSM rates. The overall PSM rate was 21%, with 28% in the first group, 20% in the second, and 16% in the third (P = 0.108). Significant lineal decreasing tendency was observed (P = 0.024). In pT2 patients, the overall PSM rate was 16.6%, with 27%, 13.8%, and 7.3% in each group respectively (P = .009). A significant difference was found between group 1 and group 3 (P = 0.004). In pT3 patients, the surgeon's experience was not significantly associated with margin reductions with an overall PSM rate of 27.7% (28.2%, 28.6%, and 26.7% in each group respectively). Conclusions: Clinical and surgical features in our patients did not vary over time. We found a significant reduction of PSM related to surgeon's experience in pT2 patients. Contrariwise, the margin status remained stable despite increasing experience in pT3 patients

Incidence of positive surgical margins after robotic assisted radical prostatectomy: Does the surgeon's experience have an influence on all pathological stages?

OBJECTIVE: The aim of this study is to analyze the clinical and surgical features of patients who underwent robotic-assisted radical prostatectomy (RARP) at our institution, and the impact of the surgeon's experience in the oncological results related to pathological stage. MATERIAL AND METHODS: An analysis of 300 RARP consecutively performed by the same urologist was conducted. Patients were divided into 3 groups of 100 patients in chronological order, according to surgery date. All patients had organ-confined clinical stage. Variables which could impact in positive margins rates were analyzed. Finally, positive surgical margins (PSM) in regard to pathological stage and surgeon's experience were compared and analyzed. RESULTS: No significant differences were found in variables which could impact in PSM rates. The overall PSM rate was 21%, with 28% in the first group, 20% in the second, and 16% in the third (P = .108). Significant lineal decreasing tendency was observed (P = .024). In pT2 patients, the overall PSM rate was 16.6%, with 27%, 13.8%, and 7.3% in each group respectively (P = .009). A significant difference was found between group 1 and group 3 (P = .004). In pT3 patients, the surgeon's experience was not significantly associated with margin reductions with an overall PSM rate of 27.7% (28.2%, 28.6%, and 26.7% in each group respectively). CONCLUSIONS: Clinical and surgical features in our patients did not vary over time. We found a significant reduction of PSM related to surgeon's experience in pT2 patients. Contrariwise, the margin status remained stable despite increasing experience in pT3 patients.

Genetic variation and gains in resistance of strawberry to Colletotrichum gloeosporioides.

Anthracnose crown rot is an important disease of strawberry primarily caused by Colletotrichum gloeosporioides in Florida and North Carolina. Information on the magnitude of additive and nonadditive genetic variation is required to define breeding strategies and to estimate potential genetic gains. However, little is known about the genetic control of resistance and its utility in breeding. Our objectives were to obtain estimates of heritabilities and of components of genetic variances, genotype-environment interactions, and gains for resistance, and to examine the effects of locations and transplant types on the estimates. An incomplete diallel mating design generated 42 full-sib families, which were propagated in plugs from seed (seedling tests) and as bare-root runner plants (clonal tests) of different genotypes of the same families. Both seedlings and clones were inoculated with C. gloeosporioides under field conditions in North Carolina and Florida during the 2010-11 season. Narrow-sense heritability (h(2)) and broad-sense heritability (H(2)) for both clones and seedlings were higher at the North Carolina location (h(2) = 0.34 to 0.62 and H(2) = 0.46 to 0.85) than at the Florida location (h(2) = 0.16 to 0.22 and H(2) = 0.37 to 0.46). Likewise, the seedling tests showed higher genetic control than the clonal tests at both locations. Estimates of dominance variance were approximately one-third of the additive variance at North Carolina and were even larger at Florida. Epistasis was negative at both locations and assumed zero for heritability (H(2)) calculations. Genotype-environment interactions were different by transplant type, suggesting rank changes across locations. 'Pelican' was the most resistant parent at both locations, followed by 'NCH09-68' at the NC location and 'Winter Dawn' at the Florida location. Selection and deployment of the most resistant clone within each of the five best families is estimated to produce average genetic gains of 53.0 and 73.7% at the North Carolina and Florida locations, respectively.